Brazing and soldering [PDF|TXT] (2023)

Brazing and Aggregate Soldering By: Paul Morrissette

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solder content

filler metal

capillary action

fluid

welding

idle

Phosphor

Nickel

Lead

Zink

Messing

Talk

copper

110

Liga

128

Lata

137

welding

151

ductility

163

Gold

166

Eisen

187

Redox

205

Aluminium

215

Mineral

230

Money

235

Stahl

251

Chemical element

263

Isotope

281

atomic number

292

half-life

296

oxygen

301

Sopormetall

323

List of hard solders

324

Induction soldering

375

amorphous solder sheet

377

soldering

378

flow (metallurgy)

379

Cuprimage

389

filling

395

solder code list

396

Specification of the welding process

402

List the DIN standard there

404

mokume-gane

442

nanofolha

444

References Article sources and contributors

446

Image sources, licenses and contributors

458

Item Licenses License

465

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Brazing Brazing is a metal joining process in which a filler metal is heated above its melting point and distributed between two or more joined parts by capillary action. The filler metal is brought slightly above its melting (liquidus) temperature while protected with a suitable atmosphere, usually a flux. It then flows over the base metal (known as wetting) and then cools to join the workpieces together.[] It is similar to brazing except the temperatures used to melt the filler metal are higher.

Basics In order to achieve quality welds, parts must be tight and the base metals exceptionally clean and free of oxides. In most cases, joint spacing of 0.03 to 0.08 mm (0.0012 to 0.0031 inch) is recommended for better capillary action and bond strength. 0.024 inches). The cleanliness of soldered surfaces is also important as any contamination can result in poor wetting (flow). The two main methods of cleaning parts before soldering are chemical cleaning and abrasive or mechanical cleaning. When cleaning mechanically, care must be taken to ensure that the surface is sufficiently rough, since wetting occurs much more easily on a rough surface than on a smooth surface of the same geometry. [] Another consideration that should not be neglected is the influence of temperature and time on the quality of welded joints. The alloying effect and wettability of the solder also increase as the temperature of the solder rises. In general, the soldering temperature should be above the melting point of the solder. However, there are several factors that influence the joint designer's choice of temperature. The best temperature is generally chosen to: (1) be the lowest possible soldering temperature, (2) minimize the effects of heat on the assembly, (3) keep filler metal-metal interactions to a minimum, and (4) to maximize the useful life of used devices or devices. [ ] In some cases, a higher temperature may be selected to accommodate other design factors (e.g., to allow the use of a different filler metal, or to control metallurgical effects, or to adequately remove surface contamination). The influence of time on the welded joint mainly influences the extent to which the above effects occur; In general, however, most production processes are chosen to minimize soldering time and associated costs. However, this is not always the case as in some non-production environments time and cost are secondary to other associated attributes (e.g. strength, appearance).

Flux For soldering operations that do not take place in an inert or reducing atmosphere environment (e.g. a furnace), a flux is required to prevent the formation of oxides during the heating of the metal. The flux also serves to remove any contamination left on the solder pads. Flux can be applied in a variety of forms including flux slurry, liquid, powder, or pre-made solder pastes that combine flux with filler metal powder. Flux can also be applied with flux-coated or flux-cored soldering irons. In both cases, flux flows into the joint when applied to the heated joint and is displaced by molten filler metal entering the joint. Excess flux must be removed when the cycle is complete as flux left in the joint can cause corrosion, make inspection of the joint difficult and prevent further finishing operations. Phosphorous brazing alloys can be self-fluxing when joining copper to copper.[1] Fluxes are generally selected based on their performance on specific base metals. To be effective, the

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The flux must be chemically compatible with both the base metal and the filler material used. Self-fluxing phosphorus addition alloys produce brittle phosphides when used on iron or nickel.[] As a general rule, longer soldering cycles should use less active flux than short soldering operations.[2]

Brazing materials Different alloys are used as brazing materials depending on the intended use or application process. Generally, braze alloys are made from 3 or more metals to form an alloy with the desired properties. The filler metal for a given application is selected based on its ability: to wet the base metals, withstand the required service conditions, and melt at a lower temperature than the base metals or at a very specific temperature. Braze is generally available in rod, ribbon, powder, paste, cream, wire, and preforms (such as stamped washers). [] Depending on the application, the filler material can be pre-placed at the desired location or applied during welding. cycle. Wire and rod forms are generally used in hand soldering because they are the easiest to apply when heating. In furnace brazing, the alloy is usually placed first as the process is usually highly automated. [] Some of the more common types of filler metals are: • Aluminum-Silicon • Copper • Copper-Silver • • • • •

Copper-Zinc (Brass) Gold-Silver Nickel Alloy Silver[][3] Amorphous Solder Sheet with Nickel, Iron, Copper, Silicon, Boron, Phosphorus etc.

Atmosphere Since soldering requires high temperatures, the oxidation of the metal surface takes place in an atmosphere containing oxygen. This may require the use of an atmospheric environment other than air. Commonly used atmospheres are[4][5] • Air: Simple and economical. Many materials are susceptible to oxidation and deposits. An acidic cleaning bath or a power cleaner can be used to remove rust after work. Flux is usually used to neutralize rust, but it can weaken the bond. • Combusted fuel gas (low-hydrogen, AWS Type 1, “exothermically generated atmospheres”): 87% N2, 11–12% CO2, 5–1% CO, 5–1% H2. For silver, copper-phosphorus and copper-zinc filler metals. For soldering copper and brass. • Combustible gas (decarburization, AWS Type 2, "Endothermic Generated Atmospheres"): 70-71% N2, 5-6% CO2, 9-10% CO, 14-15% H2. For copper, silver, copper-phosphorus and copper-zinc filler metals. For brazing copper, brass, nickel alloys, monel, medium carbon steels. • Flared fuel gas (dry, AWS Type 3, "Endothermic Generated Atmospheres"): 73-75% N2, 10-11% CO, 15-16% H2. For copper, silver, copper-phosphorus and copper-zinc filler metals. For brazing copper, brass, low nickel alloys, monel, medium and high carbon steels. • Flared fuel gas (dry, decarburized, AWS Type 4): 41-45% N2, 17-19% CO, 38-40% H2. For copper, silver, copper-phosphorus and copper-zinc filler metals. For brazing copper, brass, low nickel alloys, medium and high carbon steels. • Ammonia (AWS Type 5, also called forming gas): Dissociated ammonia (75% hydrogen, 25% nitrogen) can be used for many types of soldering and annealing. Cheap. For copper, silver, nickel, copper-phosphorus and copper-zinc filler metals. For brazing copper, brass, nickel alloys, monel, medium and high carbon steels and chromium alloys.

Brazing • Nitrogen+Hydrogen, cryogenic or purified (AWS Type 6A): 70-99% N2, 1-30% H2. For copper, silver, nickel, copper-phosphorus and copper-zinc filler metals. • Nitrogen+hydrogen+carbon monoxide, cryogenic or purified (AWS Type 6B): 70-99% N2, 2-20% H2, 1-10% CO. For filling copper, silver, nickel, phosphor-copper and copper-zinc busbars. For brazing copper, brass, low nickel alloys, medium and high carbon steels. • Nitrogen, cryogenic or purified (AWS Type 6C): Non-oxidizing, economical. At high temperatures it can react with some metals, e.g. certain steels that form nitrides. For copper, silver, nickel, copper-phosphorus and copper-zinc filler metals. For brazing copper, brass, low nickel alloys, monel, medium and high carbon steels. • Hydrogen (AWS Type 7): Powerful deoxidizer, high thermal conductivity. It can be used for soldering copper and annealed steel. Can cause hydrogen embrittlement in some alloys. For copper, silver, nickel, copper-phosphorus and copper-zinc filler metals. For brazing copper, brass, nickel alloys, monel, medium and high carbon steels and chromium alloys, cobalt alloys, tungsten alloys and carbides. • Inorganic vapors (various volatile fluorides, AWS Type 8): Special Purpose. Can be mixed with AWS 1-5 atmospheres to replace flux. It is used for soldering brass and silver. • Inert gas (usually argon, AWS Type 9): Non-oxidizing, more expensive than nitrogen. idle. The parts must be very clean, the gas must be pure. For copper, silver, nickel, copper-phosphorus and copper-zinc filler metals. For brazing copper, brass, nickel alloys, monel, medium and high carbon steels, chromium alloys, titanium, zirconium, hafnium. • Inert Gas+Hydrogen (AWS Type 9A) • Vacuum: Requires evacuation of working chamber. Expensive. Not suitable (or requires special care) for metals with high vapor pressure, e.g. silver, zinc, phosphorus, cadmium and manganese. It is used for the highest quality seals, e.g. aerospace applications.

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Common Techniques Flame Brazing Flame brazing is by far the most widely used mechanized brazing process. It is best used in small production runs or specialized operations and accounts for most soldering work in some countries. There are three main categories of torch brazing: [ ] manual, mechanical and automatic torch brazing. Hand torch soldering is a process that applies heat using a gas flame placed on or near the joint to be soldered. The torch can be held manually or in a fixed position, depending on whether the process is entirely manual or has some level of automation. Hand soldering is most commonly used in low volume manufacturing or in applications where the size or configuration of the part precludes other soldering methods. [] The main disadvantages are the high labor costs associated with the process, as well as the skill required of the operator. [6] Classification table of brazing and soldering process to obtain high quality welded joints. The use of flux or self-fluxing material is necessary to prevent oxidation. Soldering copper with a flame can be done without using flux when soldering with a hydrogen-oxygen gas torch instead of oxygen and other combustible gases. Mechanized torch brazing is commonly used when performing a repetitive brazing operation. This method is a combination of automatic and manual operations in which an operator typically places the solder, flux and assembly parts while the actual soldering is performed by the machine mechanism. [] The advantage of this method is that it reduces costs. Personnel and qualification requirements. manual soldering. This process also requires the use of fluxing agents as there is no protective atmosphere and it is best suited for small to medium production runs. Automated torch brazing is a method that virtually eliminates the need for manpower in the brazing process, except for loading and unloading the machine. The main advantages of this process are: high production rate, uniform weld quality and reduced operating costs. The equipment used is essentially the same as brazing with a mechanical torch, with the main difference being that the machine replaces the operator in preparing the part.[]

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Furnace Brazing Furnace brazing is a semi-automated process that is widely used in industrial brazing operations due to its adaptability to mass production and the use of unskilled labor. Furnace brazing has many advantages over other heating methods that make it ideal for mass production. One of the main advantages is the simplicity of the furnace soldering scheme, which allows you to make a large number of small parts that easily fit together or stand alone. local heating) and without the need for post-soldering cleaning. Commonly used atmospheres include: inert, reducing, or vacuum atmospheres, all of which protect the part from oxidation. Some other advantages are: low unit cost when used in mass production, accurate temperature control and the ability to weld multiple joints at the same time. Furnaces are typically heated with electricity, gas or oil, depending on the furnace type and application. However, the disadvantages of this method include: high investment costs, more difficult design considerations and high energy consumption. [] There are four main types of furnaces used in brazing operations: brazing-type batch; continually; controlled atmosphere autoclaves; and empty. Batch furnaces have relatively low acquisition costs and heat each batch separately. It can be turned on and off at will, reducing running costs when not in use. These furnaces are suitable for medium to high volume production and offer a high degree of flexibility in the type of parts to be welded. [ ] Controlled atmospheres or flows can be used to control oxidation and cleanliness of parts. Continuous furnaces are best suited for a constant flow of similarly sized parts through the furnace. [ ] These furnaces are typically belt fed, allowing parts to move through the hot zone at a controlled speed. It is common to use controlled atmosphere or pre-applied flux in continuous furnaces. In particular, these furnaces offer the advantage of very low personnel costs and are therefore ideally suited for large-scale production. Retort furnaces differ from other batch furnaces in that they use a sealed lining called a "retort". The retort is usually sealed or brazed and completely filled with the desired atmosphere and then externally heated by conventional heating elements. [ ] Because of the high temperatures, the retort is usually made of heat-resistant alloys that resist oxidation. . Retort furnaces are often used in batch or semi-batch designs. Vacuum furnaces are a relatively inexpensive method of rust prevention and are most commonly used to weld materials with very stable oxides (aluminum, titanium, and zirconium) that cannot be welded in atmospheric furnaces. Vacuum brazing is also commonly used on refractories and other exotic alloy combinations not amenable to atmospheric furnaces. Due to the lack of flow or reducing atmosphere, part cleanliness is critical in vacuum brazing. The three main types of vacuum furnaces are: single-walled hot autoclave, double-walled hot autoclave and cold-walled autoclave. Typical vacuum levels for brazing range from pressures of 1.3 to 0.13 pascals (unit) pascals (10-2 to 10-3 torr) to 0.00013 Pa (10-6 torr) or less. [ ] Furnace vacuum machines are generally of the discontinuous type, and are adapted to medium and high production volumes.

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Silver Brazing Silver brazing, sometimes called brazing or silver brazing, is brazing using a silver alloy based filler. These silver alloys are made up of many different percentages of silver and other metals such as copper, zinc and cadmium. Brazing is widely used in the tool industry to attach hard metal tips (carbide, ceramic, cermet, and the like) to tools such as saw blades. "Pre-tinning" is often carried out: the hard solder is melted onto the hard metal tip, which is placed next to the steel and remelted. Pre-tinning solves the problem that hard metals are difficult to wet. Brazed carbide seals are typically two to seven thousandths of an inch thick. The solder joins the materials and compensates for the different rates of expansion. In addition, it provides cushioning between the carbide tip and hard steel, which cushions impact and prevents tip loss and damage, much like a vehicle's suspension helps prevent damage to tires and the vehicle. Finally, the solder alloy bonds the other two materials together to create a composite structure, much like layers of wood and glue create plywood. The standard for welded joint strength in many industries is a joint that is stronger than one of the base materials such that when stressed, one or the other of the base materials will fail prior to the joint. A special process for brazing silver is called brazing or brazing. It was specially developed for connection cables on railways or for cathodic protection systems. The process uses a solder pin containing silver and flux that is melted into the eyelet of a cable lug. The device is normally powered by batteries.

Brazing Brazing is the use of a flux-coated brass or bronze filler rod to join steel parts together. The equipment needed for soldering is essentially identical to the equipment used in soldering. Since brazing generally requires more heat than brazing, acetylene or methyl acetylene propadiene (MAP) fuel gas is commonly used. The name comes from the fact that no capillary action is used. Brazing has many advantages over fusion welding. It allows dissimilar metals to be joined, minimizes thermal distortion and can reduce the need for extensive preheating. Since the alloyed metals are not melted, the components also retain their original shape; Edges and contours are not corroded or altered by the formation of a fillet weld T-joint. Another effect of brazing is the removal of built-up stresses that are often present in fusion welding. This is extremely important when repairing large castings. Disadvantages are the loss of strength at high temperatures and the inability to withstand high stresses. Carbide, cermet, and ceramic tips are coated and then bonded to steel to make sharp band saws. The coating acts as a hard solder.

'Brazing' of cast iron 'Brazing' of cast iron is usually a brazing operation with a filler rod composed primarily of nickel, although true welding of cast iron rods is also possible. Ductile iron pipe can also be 'cadmium brazed', a process in which the joints are joined by a small copper wire cast into the iron as it is pre-ground to bare metal, parallel to the iron joints being shaped to match Center pipe with neoprene gasket. stamps. The purpose behind this process is to use current along the copper to keep underground pipes warm in cold weather.

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Vacuum Brazing Vacuum brazing is a material joining technique that offers significant advantages: extremely clean, superior, flux-free brazed joints with high integrity and strength. The process can be expensive as it must be performed in a vacuum chamber vessel. Temperature uniformity is maintained throughout the workpiece when heated under vacuum, greatly reducing residual stresses due to slow heating and cooling cycles. This, in turn, can significantly improve the thermal and mechanical properties of the material, providing unique heat treatment capabilities. One of these possibilities is to heat treat or age the part while a metal joining process is being performed, all in a single furnace heat cycle. Vacuum brazing is usually done in an oven; This means that multiple connections can be made at the same time as the entire part reaches soldering temperature. Heat is transferred by radiation since many other methods are not applicable in a vacuum.

Dip soldering Dip soldering is particularly suitable for aluminum soldering, as it excludes air and thus prevents the formation of oxides. The parts to be joined are clamped and the solder is applied to the mating surfaces, usually in the form of a paste. The assemblies are then immersed in a bath of molten salt (typically NaCl, KCl, and other compounds) that serves as a heat transfer and flow medium.

Heating Methods There are many heating methods available to perform soldering operations. The most important factor in selecting a heating method is to achieve efficient heat transfer across the joint and this within the heat capacity of each base metal used. The geometry of the welded joint is also a crucial factor, as is the required production speed and quantity. The easiest way to categorize soldering processes is to group them by heating process. Here are some of the most common:[][7]

Torch brazing Furnace brazing Induction brazing Dip brazing Resistance brazing Infrared brazing Blank brazing E-beam and laser brazing Soldering

Pros and Cons Brazing has many advantages over other metal joining techniques such as soldering. Because soldering does not melt the base metal of the joint, it allows for much tighter control of tolerances and creates a clean joint without the need for post-processing. In addition, different metals and non-metals (e.g. metallized ceramics) can be welded. In general, brazing also produces less thermal distortion than soldering due to the uniform heating of a brazed part. Complex, multi-part assemblies can be welded at low cost. Soldered joints sometimes require leveling, an expensive secondary operation that soldering does not require as it produces a clean joint. Another advantage is that solder joints can be coated or plated for protection. Finally, soldering can be easily adapted to mass production and is easy to automate, since individual process parameters are less sensitive to fluctuations. [][8] One of the main disadvantages is: lack of bond strength compared to a brazed joint due to softer filler metals used.[]Wikipedia: Controversial statement The strength of the welded joint is probably lower than that of the base

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Metal(s) but larger than the filler metal. [citation needed] Another disadvantage is that soldered connections can be damaged at high operating temperatures. [] Brazed joints require a high level of cleaning of the base metal when made in an industrial setting. Some brazing applications require the use of appropriate fluxes to control cleanliness. The grout color often differs from that of the base metal, which is an aesthetic disadvantage.

Filler Metals Some solders come in the form of trefoils, which are laminated sheets of a base metal coated with a layer of solder on each side. The core metal is usually copper; its function is to act as a support for the alloy to withstand the mechanical stresses due to e.g. differential thermal expansion of different materials (e.g. a cemented carbide tip and a steel backing) and to act as a diffusion barrier (e.g. to prevent the diffusion of aluminum bronze to aluminum and carbon steel). solder these two).

Braze Families Braze alloys form several distinct groups; Alloys of the same group have similar properties and uses.[9] • Pure unalloyed metals. Often precious metals: silver, gold, palladium. • Ag-Cu Good melting properties. Silver improves flow. Eutectic alloy for furnace brazing. Copper rich alloys prone to ammonia stress cracking. • Ag-Zn Similar to Cu-Zn, used to fulfill marking in jewelry due to high silver content. The color matches the silver. Resistant to silver cleaning liquids containing ammonia. • Cu-Zn (brass) general purpose, used to join steel and cast iron. In the case of copper, silicon bronze, copper-nickel and stainless steel, the corrosion resistance is generally insufficient. Pretty ductile. High vapor pressure due to volatile zinc, unsuitable for furnace soldering. Copper rich alloys prone to ammonia stress cracking. • Ag-Cu-Zn Lower melting point than Ag-Cu with the same Ag content. It combines the advantages of Ag-Cu and Cu-Zn. Above 40% Zn, ductility and strength decrease, so only such low zinc alloys are used. Above 25% zinc, less ductile copper-zinc and silver-zinc phases occur. A copper content above 60% produces reduced strength and a liquidus above 900°C. Silver content above 85% leads to reduced strength, high liquidus and high cost. Copper rich alloys prone to ammonia stress cracking. Silver-rich embers (over 67.5% Ag) can be branded and used in jewelry; Alloys with lower silver content are used for technical purposes. Alloys with a copper to zinc ratio of about 60:40 contain the same phases as brass and correspond to its colour; They are used to join brass together. A small amount of nickel improves strength and corrosion resistance and promotes carbide wetting. The addition of manganese along with nickel increases fracture toughness. The addition of cadmium produces Ag-Cu-Zn-Cd alloys with better fluidity and wettability and a lower melting point; However, cadmium is toxic. Adding tin can play basically the same role. • Cu-P Widely used for copper and copper alloys. No copper flux required. It can also be used with silver, tungsten and molybdenum. Copper rich alloys prone to ammonia stress cracking. • Ag-Cu-P Like Cu-P, more liquid. Best for larger spaces. More ductile, better electrical conductivity. Copper rich alloys prone to ammonia stress cracking.

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• Au-Ag precious metals. Used in jewelry. • Au-Cu Continuous series of solid solutions. Easily wet many metals, including refractories. Narrow melting ranges, good flowability.[] Commonly used in jewelry. Alloys containing 40 to 90% gold harden on cooling but remain ductile. Nickel improves ductility. Silver lowers the melting point but degrades corrosion resistance; In order to maintain corrosion resistance, the gold grade must be maintained above 60%. The high temperature resistance and corrosion resistance can be improved by additional alloys, e.g. with chromium, palladium, manganese and molybdenum. The addition of vanadium enables the ceramic to be wetted. Low vapor pressure. • Au-Ni Continuous series of solid solutions. Broader melting range than Au-Cu alloys, but better corrosion resistance and wetting. Often alloyed with other metals to reduce the gold content and preserve its properties. Copper can be added to reduce gold content, chromium to compensate for loss of corrosion resistance, and boron to improve chromium-impaired wettability. Usually no more than 35% Ni is used since higher Ni/Au ratios have a very wide melting range. Low vapor pressure. • Au-Pd Greater corrosion resistance compared to Au-Cu and Au-Ni alloys. It is used to join superalloys and refractory metals for high-temperature applications, e.g. jet engines. Expensive. It can be replaced with cobalt-based solders. Low vapor pressure. • Pd Good high temperature performance, high corrosion resistance (less than gold), high strength (more than gold). usually alloyed with nickel, copper or silver. Forms solid solutions with most metals, does not form brittle intermetallic compounds. Low vapor pressure. • No nickel alloys, more numerous than silver alloys. High resistance. Lower cost than silver alloys. Good high temperature performance, good corrosion resistance in moderately aggressive environments. Commonly used for stainless steels and heat resistant alloys. Brittle sulfur and some low melting point metals, e.g. Zinc. Boron, phosphorus, silicon and carbon have a lower melting point and easily diffuse into base metals; this enables diffusion soldering and allows the joint to be used above the soldering temperature. Borides and phosphides form brittle phases; amorphous preforms can be made by rapid solidification. • Co-Cobalt alloys. Good corrosion resistance at high temperatures, possible alternative to Au-Pd solders. Poor processability at low temperatures, preforms made by rapid solidification. • Al-Si for brazing aluminium. • For example active alloys containing active metals. titanium or vanadium. It is used for welding non-metallic materials, e.g. graphite or ceramic.

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Role of element elements

profession

Volatility Corrosion Resistance volatile

cost

incompatibility

Talk

textural, moisturizing

copper

structurally

Zink

Structure, fusion, wetting

Aluminium

structural, active

Gold

textural, moisturizing

Super

very expensive

Excellent corrosion resistance. Very expensive. Wettes most metals.

Palladium

structurally

Super

very expensive

Excellent corrosion resistance, although lower than gold. Higher mechanical resistance than gold. Good resistance to high temperatures. Very expensive, although less than gold. Makes the joint less prone to failure due to intergranular penetration when welding [] nickel, molybdenum or tungsten alloys. Increases [ ] the high temperature resistance of gold-based alloys. It improves the high temperature resistance and corrosion resistance of gold and copper alloys. Forms solid solutions with most engineering metals, does not form brittle intermetallic compounds. High resistance to oxidation at high temperatures, especially Pd-Ni alloys.

Cadmium

structural, wetting, melting

Lead

Structure, Fusion

volatile

wasteful

description

under

AFFORDABLE PRICES

Improves capillary flow, improves corrosion resistance of less noble alloys, degrades corrosion resistance of gold and palladium. Relative expensive. High vapor pressure, problematic in vacuum brazing. Dampen the copper. Does not wet nickel and iron. Decreases the melting point of many alloys including gold-copper. ammonia

Good mechanical properties. Often used with silver. Dissolves and wets nickel. Something dissolves and wets the iron. Copper-rich alloys susceptible to stress cracking in the presence of ammonia.

Lowers the melting point. Often used with copper. Vulnerable to corrosion. Improves wetting on ferrous metals and nickel alloys. aluminum compatible. High vapor pressure, produces some toxic fumes, requires ventilation; very volatile above 500 °C. At high temperatures, it can boil over and form cavities. Vulnerable to selective leaching in some environments, which can lead to link failure. Traces of bismuth and beryllium along with tin or zinc in aluminium-based solder destabilize the oxide film on aluminum and facilitate its wetting. High affinity for oxygen, promotes the wetting of copper in air and reduces the surface film of copper oxide. Minus this advantage when soldering in a controlled atmosphere furnace. It weakens the nickel. High levels of [ ] zinc can result in a brittle alloy.

trust

Common base for heavy duty welding of aluminum and its alloys. Weakens iron alloys.

poisonous

Lowers the melting point, improves flowability. Poisonous. Produces toxic fumes, requires ventilation. High affinity for oxygen, promotes the wetting of copper in air and reduces the surface film of copper oxide. Minus this advantage when soldering in a controlled atmosphere furnace. Allows reducing the silver content of Ag-Cu-Zn alloys. Replaced by tin in more modern alloys. Lowers the melting point. Poisonous. Produces toxic fumes, requires ventilation.

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Lata

Structure, fusion, wetting

Lowers the melting point, improves flowability. Extends the range of fusion. It can be used with copper, with which it forms bronze. Improves the wetting of many difficult-to-wet metals, e.g. stainless steels and tungsten carbide. Traces of bismuth and beryllium along with tin or zinc in aluminium-based solder destabilize the oxide film on aluminum and facilitate its wetting. Low solubility [ ] in zinc, which limits its content in zinc-containing alloys.

bismuth

additive property

Lowers the melting point. May alter surface oxides. Traces of bismuth and beryllium along with tin or zinc in aluminium-based solder destabilize the oxide film on aluminum and facilitate its wetting.

Beryllium

additive property

Traces of bismuth and beryllium along with tin or zinc in aluminium-based solder destabilize the oxide film on aluminum and facilitate its wetting.

Nickel

textural, moisturizing

contralto

Chrom

structurally

contralto

Mangan

structurally

volatile

geb

Zn, S

Strong, corrosion resistant. Prevents melt flow. The addition of gold and copper alloys improves ductility and creep resistance [ ] at high temperatures. The addition of silver allows the silver and tungsten alloys to be wetted and improves adhesion. Improves the wetting of copper-based solders. Improves the ductility of gold and copper filler metals. Improves the mechanical properties and corrosion resistance of silver, copper and zinc solders. The nickel content compensates for the embrittlement caused by aluminum diffusion when welding alloys containing aluminum, e.g. aluminum bronzes. In some alloys it increases mechanical properties and corrosion resistance through a combination of solid solution strengthening, grain refinement and segregation at the valley surface and grain boundaries where it forms a corrosion resistant layer. Wide intersolubility with iron, chromium, manganese and others; such alloys can corrode severely. Embrittled by zinc, many other low melting point metals and sulphur. Corrosion resistant. Increases high temperature corrosion and strength of gold base alloys. Added to copper and nickel to increase the corrosion resistance of these and their alloys. Wets oxides, carbides and graphite; often a major component of the alloy for high temperature brazing of such materials. Impairs the wettability of gold and nickel alloys, which can be compensated for by adding boron [].

AFFORDABLE PRICES

High-pressure steam, not suitable for vacuum brazing. Ductility increases in gold-based alloys. Increases the corrosion resistance [] of copper and nickel alloys. It improves the high temperature resistance and corrosion resistance of gold and copper alloys. A higher manganese content can increase the tendency to liquefy. The manganese in some alloys tends to cause porosity in the fillets. Tends to react with graphite molds and jigs. Rusts easily, requires flux. Lowers the melting point of solders with a high copper content. Improves the mechanical properties and corrosion resistance of silver, copper and zinc solders. Cheap, even cheaper than zinc. Part of the Cu-Zn-Mn system is brittle,[] some proportions cannot be used. In some alloys it increases mechanical properties and corrosion resistance through a combination of solid solution strengthening, grain refinement and segregation at the valley surface and grain boundaries where it forms a corrosion resistant layer. Facilitates wetting of cast iron due to its ability to dissolve carbon.

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structural molybdenum

geb

Increases high temperature corrosion and strength of [ ] gold base alloys. It increases the ductility of gold-based alloys, promotes wetting of refractory materials, namely carbides and graphite. When present in alloys to be joined, it can destabilize the surface oxide layer (through oxidation and volatilization) and facilitate wetting.

Cobalt

structurally

geb

Good high temperature properties and corrosion resistance. In nuclear applications, it can absorb neutrons and enrich cobalt-60, a powerful emitter of gamma rays.

Magnesium

volatile O2 scrubber for volatiles

Indonesian

melt, wet

Money

Melt

silicon

melt, wet

Deutschland

Structure, Fusion

Boro

melt, wet

Metal misto

additive property

at a level of about 0.08% it can be used to replace boron where boron would have adverse effects.

Cer

additive property

in small amounts it improves the fluidity of welds. Particularly useful for four or more component alloys where other additives affect flow and dispersion.

Strontium

additive property

in small amounts it refines the grain structure of aluminium-based alloys.

The addition of aluminum makes the alloy suitable for vacuum brazing. Volatile, but less than zinc. Steaming promotes wetting by removing surface oxides, the fumes act as oxygen scavengers in the furnace atmosphere. expensive

Lowers the melting point. Improves the wetting of ferrous alloys by copper-silver alloys. Lowers the melting point. Can form carbides. It can diffuse into the base metal, resulting in a higher melting temperature, which can enable step brazing with the same alloy. Above 0.1%, the corrosion resistance of nickel alloys deteriorates. Traces present in stainless steel can facilitate surface chromium(III) oxide reduction in vacuum and allow flux-free soldering. Diffusion away from the braze increases its reflow temperature; [ ] exploited in diffusion soldering. Yet

wasteful

Lowers the melting point. May form silicides. Improves the wetting of copper-based solders. Encourages the flow. Causes intergranular embrittlement of nickel alloys. Diffusion rapidly into base metals. Diffusion away from the braze increases its reflow temperature; explored in diffusion soldering. Lowers the melting point. Expensive. For special applications. You can create fragile phases.

Lowers the melting point. Can form hard and brittle borides. It is not suitable for nuclear reactors. Fast diffusion for base metals. It can diffuse into the base metal, resulting in a higher melting temperature, which can enable step brazing with the same alloy. It can corrode some base materials or penetrate between the grain boundaries of many heat-resistant structural alloys and degrade their mechanical properties. Because of its interaction with neutrons, it should be avoided in nuclear applications. Causes intergranular embrittlement of nickel alloys. Improves wettability of/by some alloys, can be added to Au-Ni-Cr alloy to compensate for the loss of wettability caused by the addition of chromium. In low concentrations it improves wettability and lowers the melting point of nickel solders. Diffuses quickly into base materials, can lower melting point; especially a problem when welding thin materials. Diffusion away from the braze increases its reflow temperature; explored in diffusion soldering.

welding

Phosphor

Desoxidationsmittel

H2S, SO2, Ni, Fe, Co

Lithium

Desoxidationsmittel

deoxidizer. Eliminates the need for flux on some materials. Lithium oxide formed by reaction with surface oxides is [ ] easily displaced by the molten braze alloy.

Titan

structural, active

Most commonly used active metal. Small additions to [] Ag-Cu alloys facilitate the wetting of ceramics, e.g. silicon nitride. Most metals, with the exception of a few (i.e. silver, copper and gold), form brittle phases with titanium. When soldering ceramics, titanium, like other active metals, reacts with them and forms a complex layer on its surface, which in turn is wettable by soldering silver and copper. Wets oxides, carbides and graphite; often a major component of the alloy for high temperature brazing[] of such materials.

Zirconium

structural, active

Wets oxides, carbides and graphite; often an important alloying ingredient[] for high-temperature brazing of such materials.

We stayed

attachment

Vanadium

structural, active

Promotes wetting of alumina ceramics with gold-based alloys.

sulfur

pollution

It affects the integrity of nickel alloys. It can get into the joints through residues of lubricant, grease or paint. Forms brittle nickel sulphide (Ni3S2) which segregates at grain boundaries and causes intergranular defects.

Lowers the melting point. deoxidizer, breaks down copper oxide; Phosphorous alloys can be used on copper without flux. It does not degrade zinc oxide, so flux is required for brass. Forms brittle phosphides with some metals, e.g. Nickel (Ni3P) and iron, phosphorus alloys unsuitable for soldering with iron, nickel or cobalt content over 3%. Phosphides segregate at grain boundaries and cause intergranular embrittlement. (However, a brittle joint is sometimes desired. Frag grenades can be brazed with a phosphorus-containing alloy to produce joints that break easily on detonation.) Avoid environments where sulfur dioxide (e.g. paper mills) and hydrogen sulfide (e.g. sewers or near volcanoes); the phosphorus-rich phase corrodes rapidly in the presence of sulfur and the joint fails. Phosphorus can also be present as an impurity of [], e.g. galvanizing baths. In low concentrations it improves wettability and lowers the melting point of nickel solders. Diffusion away from the braze increases its reflow temperature; explored in diffusion soldering.

[]

Some additives and impurities work in very small amounts. Both positive and negative effects can be observed. Strontium in a concentration of 0.01% refines the grain structure of aluminium. Beryllium and bismuth in similar amounts help break down the alumina passivation layer and promote wetting. 0.1% carbon affects the corrosion resistance of nickel alloys. Aluminum can embrittle 0.001% mild steel, 0.01% phosphorus.[] In some cases, particularly vacuum brazing, high purity metals and alloys are used. Purities of 99.99% and 99.999% are commercially available. Care must be taken not to introduce harmful impurities through contamination of the joint or through dissolution of the base metals during soldering.

welding

Melting Behavior Alloys with a larger solidus/liquidus temperature range tend to melt through a "soft" state in which the alloy is a mixture of solid and liquid material. Some alloys tend to liquify and separate the liquid from the solid; for these, heating in the melting range must be fast enough to avoid this effect. Some alloys have an extended plastic range when only a small portion of the alloy is liquid and most of the material melts in the upper temperature range; these are suitable for bridging large gaps and forming fillets. High fluidity alloys are good for deep penetration into tight spaces and welding tight joints to tight tolerances, but are not good for filling larger gaps. Alloys with a wider melting range are less sensitive to uneven gaps. With a correspondingly high soldering temperature, soldering and heat treatment can be carried out simultaneously in one operation. Eutectic alloys melt at a single temperature with no soft spot. Eutectic alloys have superior dispersion; the non-eutectic ones in the soft area are highly viscous and at the same time attack the base material with a correspondingly lower expansion force. The fine grain size gives eutectics greater strength and greater ductility. Due to the high-precision melting temperature, the joining process takes place just above the melting point of the alloy. On solidification, there is no soft state in which the alloy looks solid but isn't; the possibility of disturbing the joint by handling in such a state is reduced (provided the alloy does not change its properties significantly by dissolving the base metal). The eutectic behavior is particularly advantageous for solders. [ ] Metals with a fine-grained structure before melting offer better wetting than large-grained metals. Alloy additives (e.g. strontium for aluminum) can be added to refine the grain structure and preforms or sheets can be produced by quenching. Very rapid cooling can yield an amorphous metal structure, which has other advantages.[]

Interaction with base metals For successful wetting, the base metal must be at least partially soluble in at least one component of the solder alloy. Therefore, the molten alloy tends to attack and dissolve the base metal, slightly changing its composition during the process. The change in composition is reflected in the change in the melting point of the alloy and the corresponding change in fluidity. For example, some alloys dissolve silver and copper; dissolved silver lowers its melting point and increases fluidity, copper has the opposite effect. You can take advantage of the change in melting point. Since the remelting temperature can be increased by enriching the alloy with dissolved base metal, step soldering with the same solder is possible. Alloys that do not significantly attack base metals are best for welding thin sections. The inhomogeneous microstructure of the embers can cause uneven melting and local erosion of the base metal. Wetting of base metals can be improved by adding a suitable metal to the alloy. Tin facilitates the wetting of iron, nickel and many other alloys. Copper will wet ferrous metals that silver will not attack, so copper and silver alloys can weld steels that silver alone will not wet. Zinc improves the wetting of ferrous metals, as does indium. Aluminum improves the wettability of aluminum alloys. To wet the ceramic, reactive metals can be added to the solder, which can form chemical bonds with the ceramic (e.g. titanium, vanadium, zirconium...). Dissolving base metals can cause adverse changes in the braze alloy. For example, dissolved aluminum from aluminum bronzes can weaken soldering; Adding nickel to the solder can compensate for this. The effect works both ways; Detrimental interactions between the solder and the base metal can occur. The presence of phosphorus in the solder leads to the formation of brittle iron and nickel phosphides, therefore alloys containing phosphorus are not suitable for brazing nickel and iron alloys. Boron tends to diffuse into base metals, particularly along grain boundaries, and can form brittle borides. Carbon can adversely affect some steels.

Brazing Care must be taken to avoid galvanic corrosion between the braze and the base metal and especially between different base metals that are being welded together. The formation of brittle intermetallic compounds at the alloy interface can lead to bond failure. This will be discussed later with welds. Potentially harmful phases may be evenly distributed throughout the alloy volume or concentrated at the solder base interface. A thick intermetallic interface layer is generally considered detrimental because of its low fracture toughness and other inferior mechanical properties. In some situations, e.g. This doesn't matter much since silicon chips are not usually subjected to mechanical stress. [ ] When wet, welds can release elements from the base metal. For example, aluminum-silicon brazing wets the silicon nitride, dissociates the surface to allow it to react with the silicon, and releases nitrogen, which can create voids along the junction interface and reduce its strength. Brazing nickel-gold containing titanium wets the silicon nitride and reacts with its surface, forming titanium nitride and liberating silicon; the silicon then forms brittle nickel silicides and a silicon-gold eutectic phase; The resulting compound is weak and melts at a much lower temperature than expected. [ ] Metals can diffuse from one base alloy to another causing embrittlement or corrosion. An example is the diffusion of aluminum from bronze to aluminum to an iron alloy, bonding them together. A diffusion barrier such as a copper layer may be used (e.g. in a trimet strip). A sacrificial layer of a noble metal over the base metal can be used as an oxygen barrier, preventing oxide formation and facilitating fluxless soldering. During soldering, the precious metal layer dissolves into the solder. Plating stainless steels with copper or nickel performs the same function. [] In copper brazing, a reducing atmosphere (or even a reducing flame) can react with residual oxygen in the metal, present as copper oxide inclusions, and cause hydrogen embrittlement. . The hydrogen present in the flame or in the atmosphere at high temperature reacts with the oxide and produces metallic copper and water vapor, water vapor. Vapor pockets exert high pressure on the metal structure, causing cracks and porosity in the joints. Oxygen-free copper is not sensitive to this effect, but more readily available grades, e.g. They are electrolytic copper or highly conductive copper. The brittle joint can then fail catastrophically with no prior evidence of deformation or deterioration.[10]

Preform A braze preform is a high quality, precision metal stamping used for a variety of interconnect applications in the manufacture of electronic devices and systems. Typical uses for braze preforms include connecting electronic circuits, packaging electronic devices, providing good thermal and electrical conductivity, and providing an interface for electronic connections. Square, rectangular, and disc-shaped braze preforms are commonly used to connect electronic components containing silicon dies to a substrate such as a printed circuit board. Rectangular, frame-shaped preforms are often required for the construction of electronic housings, while grommet-shaped braze preforms are typically used to connect lead wires and cable glands to circuits and electronic housings. Some preforms are also used in diodes, rectifiers, optoelectronic devices, and component packaging.[11]

fifteen

welding

sixteen

References [1] Lucas-Milhaupt SIL-FOS 18 Copper/Silver/Phosphorus Alloy (http://www.matweb.com/search/datasheet.aspx?matguid=2d38b7e2323d4f33a3916976d6c54375&ckck=1) [4] The Brazing Guide (http: / / www.inductionatmospheres.com/pdf/BrazingGuide.pdf) [6] AWS A3.0:2001, Standard Welding Terms and Definitions, including terms for bonding, brazing, soldering, thermal cutting and thermal spraying, American Welding Society (2001 ) , p. 118. ISBN 0-87171-624-0 [11] http://www. Embossing with/preforms. asp

References • Groover, Mikell P. (2007). Fundamentals of Modern Manufacturing: Processes and Material Systems (2nd ed.). John Wiley & Sons. ISBN978-81-265-1266-9. • Schwartz, Mel M (1987). Welding. ASM International. ISBN978-0-87170-246-3.

Weiterführende Literatur • Fletcher, M.J. (1971). Vakuumschweißen. London: Mills and Boon Limited. ISBN0-263-51708-X. • PN. Roberts, „Industrial Brazing Practice“, CRC Press, Boca Raton, Florida, 2004. • Kent White, „Authentic Aluminium Gas Brazing: Plus Brasing and Soldering“. Herausgeber: TM Technologies, 2008. • Andrea Cagnetti „Experimental Study on Fluid Brazing in the Art of Ancient Goldsmithing“ – International Journal of Material Research (2009) DOI 10.3139/146.101783 (http://www.ijmr.de/ijmr/o_archiv . asp ?o_id=25112811648-50&ausgabe_id=2912131822-237&artikel_id=2912131825-6865&task=03&j=2009&h=01&nav_id=0)

Externe Links • • • •

The Brazing Guide (http://www.inductionatmospheres.com/brazing.html) Brazing and Brazing Aluminum, Copper, Brass etc. (http://www.tinmantech.com/html/faq_brazing.php) European Brazing and Soldering Association (http://www.brazingandsolding.org) Brazing (http://www.tpub.com/content/construction/14250 /css/14250_126.htm)

filler metal

Filler Metal A filler metal is a metal that is added when making a joint by soldering, brazing, or brazing. There are four types of filler metals: covered electrodes, bare electrode wire or rod, tubular electrode wire, and flux. Non-consumable electrodes are also sometimes included, but since these metals are not consumed in the welding process, they are generally excluded.

Use of Covered Electrodes Covered electrodes are commonly used in shielded metal arc welding and are a major factor in the popularity of this process.

Bare electrode wires Bare electrode wires are used in gas metal arc welding and bare electrode rods in gas tungsten arc welding.

Electrode core wires Electrode core wires are used in flux cored arc welding.

Welding flux Welding fluxes are used in SAW.

References • Cary, Howard B. and Scott C. Helzer (2005). Modern welding technology. Upper Saddle River, New Jersey: Pearson Formation. ISBN 0-13-599290-7

capillary action

Capillary Action Capillary action (sometimes capillarity, capillary movement, or absorption) is the ability of a liquid to flow in confined spaces unaided and against external forces such as gravity. The effect can be observed when liquids are drawn between the bristles of a brush, in a thin tube, in porous materials such as paper, in some non-porous materials such as liquefied carbon fibers, or in a cell. It occurs due to intermolecular forces between the surrounding liquid and solid surfaces. If the pipe diameter is small enough, the combination of surface tension (caused by cohesion within the liquid) and the forces of adhesion between the liquid and the vessel will cause the liquid to rise.[1]

History The first work by Albert Einstein[2], presented in the Annals of Physics in 1900, concerned capillarity. It was entitled Conclusions of the capillarity phenomena, which translated as Conclusions of the capillarity phenomena, found in Volume 4, page 513 (published 1901).

Capillary action of water with respect to mercury, each related to a polar surface, e.g. Glass

Capillary Action Phenomena and Physics A common device used to demonstrate the first phenomenon is the capillary tube. When the lower end of a vertical glass tube is immersed in a liquid such as water, a concave meniscus forms. Adhesive forces between the liquid and the inner wall of the solid push the liquid column up until there is enough liquid mass for the gravitational forces to overcome these intermolecular forces. The contact length (at the edge) between the top of the liquid column and the pipe is proportional to the pipe diameter, while the weight of the liquid column is proportional to the square of the pipe diameter, so a narrow pipe pulls a liquid column higher than a wide pipe.

Capillary Flow Experiment to study capillary flows and phenomena onboard the International Space Station

In plants and trees, capillary action in trees is enhanced by branching, evaporation in the leaves leading to depressurization, and likely additional osmotic pressure in the roots and possibly other parts of the plant, particularly as moisture accumulates in the aerial roots.[ 3] [4]

capillary action

Examples Capillary action is essential to drain the tear fluid constantly produced by the eye. In the inner corner of the eyelid are two small-diameter tubules, also called tear ducts. their openings can be seen with the naked eye in the lachrymal sacs when the eyelids are everted. The wick is the absorption of a liquid by a material in the form of a candle wick. Paper towels absorb liquid through capillarity, which allows liquid to transfer from a surface to the towel. The tiny pores of a sponge act like tiny capillaries, allowing it to absorb a comparatively large amount of liquid. Some fabrics are said to use capillary action to wick sweat away from the skin. These are often referred to as wicking fabrics due to the wicking action of candle and lamp wicks. Capillary action is observed in thin layer chromatography, where a solvent moves vertically up a plate by capillary action. In this case, the pores are spaces between very small particles. For some pairs of materials, such as mercury and glass, the intermolecular forces within the liquid exceed those between the solid and the liquid, resulting in a convex meniscus and reverse capillary action. In hydrology, capillary action describes the attraction of water molecules to soil particles. Capillary action is responsible for the movement of groundwater from moist soil areas to dry areas. Differences in soil potential ( ) drive capillary action in the soil.

Height of a meniscus The height h of a liquid column is given by:[5]

where is the liquid-air surface tension (force/unit length), θ is the contact angle, ρ is the density of the liquid (mass/volume), g is the intensity of the local gravitational field (force/unit mass), and r is the pipe radius (length). For a glass tube filled with water in air under standard laboratory conditions, γ = 0.0728 N/m at 20°C, θ = 0° (cos(0) = 1), ρ is 1000 kg/m3 and g = 9, 81m/s2. The height of the water column applies to these values

Thus, for a 4 m (13 ft) diameter glass tube under the above laboratory conditions (2 m (6.6 ft) radius), the water would imperceptibly rise 0.007 mm (0.00028 in). However, a 4 cm (1.6 in) diameter (2 cm (0.79 in) radius) pipe would increase the water by 0.7 mm (0.028 in) and a 0.028 in diameter pipe would increase the water by 4 mm (0.016 inches) (radius 0.2 mm (0.0079 in)), the water would rise 70 mm (2.8 in).

Fluid Transport in Porous Media When a dry porous medium, such as a brick or wick, comes into contact with a liquid, it begins to absorb the liquid at a rate that decreases over time. For a rod of material with cross-sectional area A that is wet on one side, the cumulative liquid volume V is recorded after a time t

where S is the sorption of the medium with dimensions m/s1/2 or mm/min1/2. The sum

Capillary flow in bricks with a sorption of 5.0 mmmin-1/2 and a porosity of 0.25.

capillary action

is referred to as cumulative fluid intake, with the dimension of length. The wet length of the rod, i.e. the distance between the wet end of the rod and the so-called wet front, depends on the fraction f of the volume occupied by the liquid. This f-number is the porosity of the medium; the wet length is then

Some authors use the S/f value as sorption.[6] The above description applies to the case where gravity and evaporation are not involved. Sorption is a relevant property of building materials because it affects the amount of rising moisture. Some building material sorption values can be found in the table below. material

Sorcery source (mm min-1/2)

Aerated concrete 0.54

[7]

and this is

3,50

[7]

brick

1.16

[7]

References [3] [4] [5] [6]

Tree Physics (http://npand.wordpress.com/2008/08/05/tree-physics-1/ ) on the Neat, Plausible And scholarly talk page. Water in Redwood and Other Trees, Primarily Through Evaporation (http://www.wonderquest.com/Redwood.htm) Article on the Wonderquest website. G K. BS, "Introduction to Fluid Dynamics", Cambridge University Press (1967) ISBN 0-521-66396-2 C. Hall, WD Hoff, Water transport in brick, stone and concrete. (2002) Page 131 at Google Books (http://books.google.com/books?id=q-QOAAAAQAAJ& lpg=PA131& ots=tq5JxlmMUe& pg=PA131#v=onepage& q& f=false) [7] Hall and Hoff , p. 122

fluid

Liquidus The liquidus temperature, TL or Tliq, is used primarily for glasses, alloys, and rocks. Indicates the maximum temperature at which the crystals can coexist with the melt in thermodynamic equilibrium. Above the liquidus temperature, the material is homogeneous and liquid in equilibrium. Depending on the material, more and more crystals can form in the melt below the liquidus temperature if you wait long enough. However, homogeneous glasses can also be obtained below the liquidus temperature by sufficiently rapid cooling, ie by kinetic inhibition of the crystallization process.

Liquidus temperature curve in the SiO2-Li2O binary glass system, [1] based on 91 published data collected in SciGlass; Model adaptation from [2] Glassproperties.com

The crystalline phase that crystallizes first when a substance is cooled to its liquidus temperature is called the primary crystalline phase or primary phase. The compositional range within which the primary phase remains constant is known as the primary crystal phase field. The liquidus temperature is important in the glass industry because crystallization can cause serious problems during the glass forming and melting processes and can also lead to product failure. The liquidus temperature can be compared to the solidus temperature. The solidus temperature quantifies the point at which a material completely solidifies (crystallizes). The liquidus and solidus temperatures do not necessarily match or overlap; When there is a gap between the liquidus and solidus temperatures, the material within that gap is composed of solid and liquid phases simultaneously (like a suspension). For pure substances, e.g. pure metal, pure water, etc. liquidus and solidus have the same temperature and the term "melting point" can be used. For impure substances, e.g. alloys, tap water, cola, ice etc. instead the melting point is extended into a melting range. If the temperature is in the melting range, "slurries" can be seen in equilibrium, i.e. the slurries solidify or do not melt completely. As a result, high-purity fresh snow melts or stays solid, while dirty snow tends to form slush on the ground at certain temperatures. Weld puddles with high sulfur content, either from molten impurities in the base metal or the welding electrode, often have very large melting areas, leading to an increased risk of hot cracking.

welding

Welding White welding is a process of joining two or more metal members by melting and flowing a filler metal (weld) in union, where the filler metal has a melting point lower than the pieza of the work. Welding differs from brazing in that brazing does not fuse the workpieces together. In brazing, the filler metal melts at a higher temperature, but the metal of the workpiece does not. Almost all solder used to contain lead, but environmental concerns have increasingly dictated the use of lead-free alloys for electronic and plumbing purposes. Unsolder one cable contact.

Origins There is evidence that welding was used in Mesopotamia 5,000 years ago.[1] Soldering and brazing are believed to have appeared very early in the history of metallurgy, probably before 4000 BC. C [2]. Sumerian swords from about 3000 BC C. were assembled by hard welding. Historically, solder has been used to make jewelry, cookware, and tools, as well as for other purposes such as assembling stained glass.

Applications Solder is used in plumbing, electronics and metallurgy for everything from lightning to jewelry. Brazing provides reasonably permanent but reversible connections between copper tubing in plumbing systems, as well as connections in sheet metal objects such as food cans, roofs, rain gutters, and car radiators.

Small figure made by welding.

Jewelry components, machine tools, and some refrigeration and plumbing components are typically assembled and repaired using the high temperature silver soldering process. Small mechanical parts are also often soldered or brazed. Solder is also used to join sheets of lead and copper in stained glass. It can also be used as a semi-permanent patch for a leak in a pot or container. Electronic soldering involves connecting electrical wires and electronic components to printed circuit boards (PCBs).

Solder fillers are available in many different alloys for different applications. When assembling electronic components, the eutectic alloy of 63% tin and 37% lead (or 60/40, which has an almost identical melting point) was the alloy of choice. Other alloys are used for plumbing, mechanical assembly, and other applications. Some examples of solder are tin-lead for general purpose, tin-zinc for joining aluminum, lead-silver for room temperature resistance, cadmium-silver for high temperature resistance, zinc-aluminum for aluminum and corrosion resistance. and tin silver and tin bismuth for electronics.

Brazing A eutectic formulation has advantages in brazing: the liquidus and solidus temperatures are the same, so there is no plastic phase and it has the lowest possible melting point. The lowest possible melting point minimizes the thermal stress on the electronics during soldering. And because it has no plastic phase, it allows for faster wetting as the solder heats up and faster curing as the solder cools. A non-eutectic formulation must remain immobile while the temperature is reduced by the liquidus and solidus temperatures. Any movement during the plastic phase can cause cracks, resulting in an unreliable connection. Common tin and lead based solder formulations are listed below. The fraction represents the percentage of tin first, then lead, totaling 100%: • 63/37: melts at 183°C (361°F) (eutectic: the only mixture that melts at one point and not in a band) • 60 /40: melts between 183 and 190 °C (361 and 374 °F) • 50/50: melts between 185 and 215 °C (365 and 419 °F) For environmental reasons (and implementing regulations such as the European RoHS Directive ( Restriction of Hazardous Substances Regulation)), lead-free solders are increasingly being used. They are also recommended anywhere small children might come into contact with them (since small children are likely to put things in their mouths) or for outdoor use where rain and other precipitation could wash lead into waterways. . Unfortunately, most lead-free solders are not eutectic formulations, they melt at around 482°F (250°C), making them difficult to make reliable connections with. Other common solders include low-temperature formulations (often containing bismuth), which are often used to join previously soldered assemblies without loosening previous joints, and high-temperature formulations (often containing silver), used for high-temperature operations. or for the initial assembly of elements that must not be desoldered during further operation. Alloying silver with other metals changes its melting point, adhesive and wetting properties, and tensile strength. Of all brazing alloys, silver brazing alloys have the highest strength and the broadest applications.[2] Specialty alloys are available with properties such as increased strength, weldability of aluminum, better electrical conductivity and greater corrosion resistance.[]

Flux The purpose of flux is to make the soldering process easier. One of the obstacles to a successful solder joint is contamination at the joint, such as dirt, oil, or oxidation. Contaminants can be removed by mechanical cleaning or chemical means, but the high temperatures required to melt the filler metal (the weld) promote re-oxidation of the workpiece (and the weld). This effect accelerates with increasing soldering temperatures and can completely prevent the solder from adhering to the workpiece. One of the first fluxes was charcoal, which acts as a reducing agent, preventing oxidation during the soldering process. Some fluxes go beyond simple rust prevention and also offer some form of chemical (corrosion) cleaning. For many years the most common flux used in electronics (soldering) was resin-based, using the resin of selected pine trees. It was ideal because it was non-corrosive and non-conductive at normal temperatures, but became slightly reactive (corrosive) at elevated soldering temperatures. Plumbing, automotive and other applications often use an acid-based flux (muriatic acid) that allows grout cleaning. These fluxes cannot be used in electronics because they are conductive and will eventually dissolve small diameter wires. Many fluxes also act as wetting agents in the soldering process[3] by reducing the surface tension of the molten solder, allowing it to flow and wet parts more easily. Soldering fluxes are currently available in three basic formulations: 1. Water-soluble fluxes: Higher activity fluxes that can be washed off after soldering (no VOCs are required for removal). 2. No-Clean Flux: Soft enough not to be removed due to its non-conductive, non-corrosive residue.[4] These fluxes are referred to as "no-clean" because the residue left after the soldering process is not and will not be conductive

welding causes a short circuit; However, they leave behind a clearly visible white residue, similar to diluted bird droppings. Unclean flux residues are acceptable on all 3 classes of PCBs per IPC-610 provided they do not impede visual inspection, access to test points, or have wet, tacky, or excessive residue that can spread to other areas. The contact surfaces of the connectors must also be free of flux residues. Clean, residue-free fingerprints are a Class 3 error[5] 3. Conventional rosin fluxes: Available in unactivated (R), slightly activated (RMA) and activated (RA) formulations. RA and RMA fluxes contain resin in combination with an activating agent, usually an acid, which increases the wettability of the metals to which it is applied and removes any oxides present. Residues from the use of RA flux are corrosive and must be removed. RMA flux is formulated to leave a residue that is not significantly corrosive, cleaning is preferred but optional. Flow performance must be carefully evaluated; A very smooth "dirty" flow may be perfectly acceptable for production equipment, but would not provide adequate performance for a poorly controlled manual soldering operation.

Processes There are three types of soldering, each requiring increasingly higher temperatures and yielding an increasingly stronger joint: 1. Solder, which originally used an alloy of tin and lead as the filler metal, 2. Silver solder, which used an alloy containing silver, 3. Brazing , in which a brass alloy is used as a filler. The filler metal alloy for each weld type can be adjusted to modify the melting temperature of the filler material. Brazing differs significantly from bonding in that filler metals are bonded to the workpiece at the joint to form a gas- and liquid-tight bond.[4] Brazing is characterized by a filler metal melting point below about 400 °C (752 °F), [7] while silver brazing and soldering uses higher temperatures, often requiring a flame or [6] Carbon arc brazing and torch classification table welding process to achieve a filler melt. Braze filler metals are typically alloys (often with lead) that have liquidus temperatures below 350°C. In this soldering process, heat is applied to the parts to be joined, causing the solder to melt and adhere to the workpieces in an alloying process called wetting. With stranded wire, solder is drawn into the wire by capillary action in a process called “wicking”. Capillary action also occurs when workpieces are close together or in contact. The connection tensile strength depends on the filler metal used. Welding creates electrically conductive, watertight and gas-tight connections.

Welding Each type of welding has advantages and disadvantages. Soft solder is named for the soft lead that is its main ingredient. Welding uses the lowest temperatures but does not form a strong bond and is not suitable for mechanically demanding applications. It is also not suitable for high temperature applications as it will soften and melt. Silver solder, used by jewelers, mechanics, and in some plumbing applications, requires the use of a torch or other high temperature source and is much stronger than solder. Brazing offers the strongest bond, but it also requires higher temperatures to melt the filler metal, requiring a flashlight or other high-temperature source and sunglasses to protect your eyes from the bright light produced by hot-hot work. It is often used to repair cast iron items, wrought iron furniture, etc. Welding can be done with hand tools, one joint at a time, or in bulk on a production line. Hand soldering is usually done with a soldering iron, soldering gun, or blowtorch, or occasionally with a hot air gun. Sheet metal work was traditionally done with "solders" heated directly by a flame, with enough heat stored in the bulk of the solder to make a connection. Flashlights or electric soldering irons are more convenient. All brazed joints require the same elements of cleaning the metal parts to be joined, assembling the joint, heating the parts, applying flux, applying putty, dissipating heat, and holding the assembly steady until the filler metal is fully solidified. Depending on the type of flux used, it may be necessary to clean the joints after they have cooled. Each alloy has properties that are best suited for specific applications, most notably strength and conductivity, and each type of solder and alloy has different melting temperatures. The term silver solder also indicates the type of solder used. Some solders are "silver-containing" alloys used to solder silver-plated items together. Lead based solders should not be used on precious metals as lead will dissolve and mar the metal.

Soldering and Soldering The distinction between soldering and brazing is based on the melting temperature of the solder alloy. A temperature of 450°C is normally used as a practical point of demarcation between soldering and brazing. Soldering can be done with a hot iron, while the other methods require a higher temperature torch or oven to melt the filler metal. Because a soldering iron cannot reach high enough temperatures for soldering or soldering, different equipment is often needed. Solder filler metal is stronger than silver solder which is stronger than lead based solder. Solder solders are primarily designed for strength, silver solder is used by jewelers to protect precious metals and by mechanics and refrigeration technicians for its tensile strength but lower melting temperature than silver. Brazing, and the main advantage of soldering is the low temperature used (to avoid heat damage to electronics and insulation). Because the joint is made using a metal with a lower melting temperature than the workpiece, the joint weakens as the ambient temperature approaches the melting point of the filler metal. Because of this, processes at higher temperatures result in bonds that are effective at higher temperatures. Solder joints can be as strong or nearly as strong as the parts they connect,[8][9] even at elevated temperatures. [10]

Silver solder "hard solder" or "silver solder" is used to join precious and semi-precious metals such as gold, silver, brass and copper. Welding is usually labeled as light, medium or heavy. This refers to the melting temperature, not the strength of the joint. Extra Easy Solder contains 56% silver and has a melting point of 618°C (1145°F). The extra braze is 80% silver and melts at 740°C (1370°F). If multiple joints are required, the jeweler will start with a hard or extra hard solder and move to lower temperature solders for subsequent joints. The silver solder absorbs into the surrounding metal, resulting in a bond that is actually stronger than the metal being joined. The metal to be joined must be perfectly flat as silver solder usually cannot be used as a filler and gaps will remain.

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Another difference between soldering and brazing is how the solder is applied. Soldering generally uses rods that touch the joint while being heated. With silver solder, small pieces of soldering wire are placed on the metal before it is heated. A flux, usually made from boric acid and denatured alcohol, is used to keep the metal and solder clean and to stop the solder from moving before it melts. When silver solder melts, it tends to flow into the area of highest heat. Jewelers can somewhat control the direction the plumb bob moves by guiding it with a flashlight; it even runs the length of a seam.

Induction Brazing Induction brazing uses high frequency AC induction heating on a surrounding copper coil. This induces currents in the part to be welded, which generate heat due to the increased resistance of a connection compared to the surrounding metal (resistance heating). These copper coils can be shaped to more closely fit the connection. A filler metal (solder) is placed between the shell surfaces and this solder melts at a reasonably low temperature. Fluxes are commonly used in induction brazing. This technique is particularly useful for continuous welding, where these coils wrap around a cylinder or pipe to be welded. Some metals are easier to weld than others. Copper, silver and gold are easy. Iron, mild steel and nickel are the next difficulties. Due to their strong and thin oxide layers, stainless steel and aluminum are even more difficult to weld. Titanium, magnesium, cast iron, some high-carbon steels, ceramics and graphite can be welded, but it requires a similar process to joining carbides: they are first coated with a suitable metallic element that induces interfacial joining.

Electronic Components (PCBs) Today, in mass production, printed circuit boards (PCBs) are most commonly wave or reflow soldered, although hand soldering of production electronics is still standard. In wave soldering, parts are temporarily held in place with small drops of glue, then the assembly is passed over the solder, which flows into a bulk reservoir. This solder is moved in waves so that the entire circuit board is not immersed in the solder but is touched by these waves. The end result is that solder remains on the pins and pads but not on the circuit board. Reflow soldering is a process that uses solder paste (a mixture of pre-bonded solder powder and a flux with a consistency similar to peanut butter[4]) to connect components to their pads. Gasket, after which the bracket is mounted. heated by an infrared lamp, a hot air pen, or more commonly by a carefully controlled oven. Because different components are best assembled using different techniques, it is common to use two or more processes for a given circuit board. For example, surface mount parts can be reflow soldered first, followed by a wave soldering process for the through-hole mount components, and the bulkier parts are hand soldered last. When hand soldering, the heat source tool must be selected to provide adequate heat for the size of joint to be made. A 100 watt soldering iron can deliver a lot of heat to circuit boards,

A multi-core electronic soldering pipe for manual soldering

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while a 25-watt iron doesn't provide enough heat for large electrical outlets, the flashing copper roof joint, or the lead of a large stained-glass window. Using a tool that's too hot can damage sensitive components, but prolonged heating from a tool that's too cold or underpowered can also cause major heat damage. Hand soldering techniques require great skill to be used in so-called fine soldering of chip packages. Ball Grid Array (BGA) devices in particular are notoriously difficult, if not impossible, to rework by hand.

A poorly welded “cold” joint

When connecting electronic components to a circuit board, the correct selection and use of flux helps prevent oxidation during soldering, which is essential for good wetting and heat transfer. The soldering iron tip must be clean and pre-tinned with solder to ensure rapid heat transfer. Components that give off large amounts of heat during operation are sometimes raised above the circuit board to prevent the circuit board from overheating. After inserting an assembled component into a through hole, the excess lead is trimmed off, leaving a length approximately equal to the radius of the pad. Plastic or metal mounting clips can be used on large devices to help dissipate heat and reduce stress on the connections. A heat sink can be used on the leads of heat-sensitive components to reduce heat transfer to the component. This applies in particular to broken solder joints on germanium parts of a printed circuit board. (Note that heat sink means more heat is required to complete the joint.) If all metal surfaces are not properly fluxed and not raised above the melting temperature of the solder used, the result is a "cold joint", which is unreliable. To make soldering easier, beginners are often advised to position the soldering iron and solder separately onto the joint instead of applying the solder directly to the soldering iron. When a sufficient amount of solder has been applied, the solder wire is withdrawn. If the surfaces are properly heated, the solder will flow around the joint. The iron is then removed from the joint. Because non-eutectic solder alloys have a small band of plastic, the joint should not move until the solder is cooled by liquidus and solidus temperatures. On visual inspection, a good solder joint will appear smooth and shiny with the outline of the soldered wire clearly visible. A dull gray surface is a good indicator of a joint that moved during welding. Other soldering defects can also be detected visually. Too little solder will result in a dry, unreliable connection; Too much solder (the familiar "solder bubble" for beginners) isn't necessarily a bad thing, but it does tend to mean some moisture. With some fluxes, it may be necessary to remove flux residue from the joint with water, alcohol, or other solvent compatible with the parts involved. Excess solder and flux and uneaten residue are sometimes removed by the soldering iron tip between joints. The tip of the iron is kept wet with solder ("tin") when hot to minimize oxidation and corrosion of the tip itself. Environmental legislation in many countries and throughout the European Community (see RoHS) has resulted in a change in the formulation of solders and fluxes. Non-resin based water soluble fluxes have been used increasingly since the 1980's to allow soldered boards to be cleaned with water or water based cleaners. This removes hazardous solvents from the production environment and plant effluent.

Hot-bar reflow soldering Hot-bar reflow soldering is a selective soldering process in which two parts coated with pre-melted solder are heated with a heating element (called a thermode) to a temperature sufficient to melt the solder. Pressure is applied throughout the process (usually 15 seconds) to ensure the components stay in place while they cool. The heating element heats and cools for each port. Up to 4000W can be used on the heating element, allowing for fast soldering and good results on power-hungry joints.[11] Laser Laser welding is a technique that uses a ~30-50W laser to melt and weld an electrical joint. For this purpose, diode laser systems based on semiconductor junctions are used.[12] The wavelengths typically range from 808 nm to 980 nm. With fiber diameters of 800 µm and smaller, the beam is guided to the workpiece via an optical fiber. Because the beam exiting the end of the fiber is rapidly diverging, lenses are used to create an appropriate spot size on the workpiece at an appropriate working distance. A wire feeder is used to feed solder.[13] Both lead-tin and silver-tin materials can be soldered. The process recipes differ depending on the composition of the alloy. To solder 44-pin chip carriers to a board using solder preforms, power levels were on the order of 10 watts and soldering times were approximately 1 second. Low power levels can lead to incomplete wetting and cavitation, which can weaken the connection.

Fiber Focused Infrared Soldering Fiber focused infrared soldering is a technique where many infrared sources are passed through fibers and then focused to a single point where the joint is soldered.[14]Wikipedia: Verifiability

Brazing Tubing Copper tubing or "tube" is usually joined by brazing. In commercial plumbing applications, soldering is more commonly referred to as brazing, and a pipe joint made in this manner is known as a brazed joint. Copper tubing conducts heat much faster than a soldering iron or soldering gun can supply it, so a propane torch is most commonly used to provide the necessary power; For large pipe and fittings, use a MAPP torch, acetylene or propylene with atmospheric air as the oxidizer; MAPP†/oxygen or acetylene/oxygen brazed copper tubing is rarely used because the flame temperature is much higher than the melting point of copper. Too much heat destroys the condition of hardened copper tubing and can burn flux out of a joint before solder is added, resulting in a poor joint. For larger pipe sizes, a torch fitted with various sizes of interchangeable swirl tips is used to provide the power required. Most experienced installers rarely use propane. In the hands of a skilled craftsman, the hottest acetylene, MAPP or propylene flame can make more connections per hour.

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Brazed fittings, also known as capillary fittings, are short lengths of plain tubing designed to slide over the outside of connecting tubing and are typically used for copper connections. Commonly used joints include straight, reducer, bend, and T-joints. There are two types of solder connections: feeder end connections, which do not contain solder, and solder ring connections (commonly known as Yorkshire connections), in which ring solder resides in a small circular recess inside the connection. As with all soldered joints, all parts to be joined must be clean and rust-free. Internal and external wire brushes are available for common pipe and fitting sizes; Emery cloth and steel wool are also commonly used, although metal wool products are discouraged as they may contain oil which would contaminate the bond.

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Sanitary fluxes are often more chemically active and acidic than electronic fluxes due to the size of the parts involved and the high activity and tendency to flame fouling. Because plumbing connections can be made at any angle, including upside down, plumbing fluxes are often formulated as pastes that hold in place better than liquids. Flux should be applied to all surfaces of the joint, inside and out. Residual flux must be removed after the joint is completed or it can eventually corrode the copper substrates and cause joint failure. There are many solder formulations for plumbing solders with different properties such as e.g. B. higher or lower melting temperature available depending on the specific work requirements. Lead-free solder building codes now almost universally mandate the use of lead-free solder for potable water pipes, although traditional tin-lead solder is still available. Studies have shown that plumbing pipes soldered with lead can produce elevated levels of lead in drinking water.[15][16] Because copper tubing quickly conducts heat away from a joint, great care must be taken to ensure the joint is properly heated to obtain a good bond. After the joint has been cleaned, fused and properly assembled, the torch flame is applied to the thickest part of the joint, usually the joint to the inside of the pipe, applying the solder to the gap between the pipe and the fitting. When all parts are heated, the solder melts and flows into the joint by capillary action. It may be necessary to move the torch around the joint to ensure all areas are wet. However, the fitter must be careful not to overheat the areas to be soldered. If the tube starts to discolor, it means the tube has overheated and is beginning to oxidize, stopping the solder flow and not sealing the joint properly. Before oxidizing, the molten solder follows the heat of the torch around the joint. When the joint is properly wetted the solder is removed and then the heat removed and while the joint is still very hot it is usually wiped clean with a dry cloth. This will remove excess solder and flux residue before it cools and hardens. In a solder ring joint, the joint is heated until a ring of molten solder is visible around the edge of the joint and allowed to cool. Brazed joints are generally considered the most difficult of the three methods of joining copper tubing, but brazing copper is a very simple process as long as a few basic conditions are met:

Soldering • Pipes and fittings must be cleaned to a bare metal surface and spotless • Any pressure built up by heating the pipe must have a vent • The joint must be dry (making soldering water pipe repairs difficult and time consuming) Copper is just a Material that is connected in this way. Brass fittings are often used for valves or as a connection between copper and other metals. Brass tubing is soldered in this way in the manufacture of brass and some wind instruments (saxophone and flute).

Aluminum and mechanical welding Various welding materials are used to weld aluminum and alloys, and to a lesser extent steel and zinc, mainly zinc alloys. This mechanical welding is similar to a low temperature brazing process as the mechanical properties of the joint are quite good and it can be used for structural repairs of these materials. The American Welding Society defines brazing as the use of filler metals with melting points above 450 °C (842 °F) or, in the traditional US definition, above 800 °F (427 °C). ). Aluminum brazing alloys generally have melting temperatures around 730°F (388°C).[17] This soldering process can use a propane torch heat source.[18] These materials are often advertised as "aluminum welding," but the process does not involve melting the base metal and is therefore not a weld per se. The US Military Standard or MIL-SPEC MIL-R-4208 defines a standard for these zinc-based solder/solder alloys.[19] Several products meet this specification.[18][20][21] or very similar performance patterns.[17] Resistance welding is welding in which the heat required to flow the solder is generated by passing an electric current through the solder. When current is passed through a resistive material, some heat is generated. By regulating the amount of current conducted and the level of resistance encountered, the amount of heat generated can be predetermined and controlled. Electrical resistance (often referred to as the resistance of a material to the flow of an electric current) is used to convert electrical energy into thermal energy when an electric current (I) passed through a material of resistance (R) has energy (P ) equals to : P = I² R where P is power measured in watts, I is current measured in amperes and R is resistance measured in ohms.

Resistance Soldering Resistance soldering differs from the use of a thermal iron, in which heat is generated within an element and then passed through a thermally conductive tip to the joint area. A cold soldering iron takes time to warm up and needs to be kept warm between solder joints. Heat transfer can be inhibited if the tip is not kept sufficiently wet during use. In resistance welding, intense heat can be developed directly in the joint area, quickly and in a tightly controlled manner. This allows for a faster increase in the required solder melt temperature and minimizes thermal displacement away from the solder joint, minimizing the potential for thermal damage to surrounding materials or components. Heat is only generated while each joint is being made, making resistance welding more energy efficient. Resistance soldering equipment, unlike conduction irons, can be used for difficult soldering and brazing applications where significantly higher temperatures may be required. As a result, the resistance is comparable to flame welding in some situations. If the required temperature can be reached by flame or resistance methods, the resistance heat is more localized due to direct contact while the flame spreads and heats a potentially larger area.

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Soldering Stained Glass Historically, stained glass soldering tips were made of copper that was heated by placing it in a brazier. Various clues were used; When one end became cold from use, it was returned to the charcoal pan and the next end used. Recently, electrically heated soldering irons have been used. These are heated by a coil or ceramic heating element in the tip of the iron. Various power levels are available and the temperature can be regulated electronically. These features allow you to run longer cables without stopping to change tips. Soldering irons designed for electronic use are often effective, although sometimes too weak for the heavy copper and lead used in stained glass work. Oleic acid is the classic flux used to improve solderability. Tiffany-type stained glass is made by gluing copper foil around the edges of pieces of glass and then soldering them together. This method allows you to create three-dimensional stained glass.

Weldability The weldability of a substrate is a measure of the ease with which a weld can be made with that material.

Desoldering and resoldering Used solder contains some dissolved base metals and is not suitable for reuse in making new connections. Once the weld has reached base metal capability, it will no longer bond properly to the base metal, usually resulting in a cold, brittle brazed joint with a crystalline appearance. It is good practice to desolder a connection before re-soldering; Desoldering braids or vacuum desoldering devices (soldering cups) can be used. The desoldering wicks contain enough flux to remove contaminants from the copper trace and any existing equipment wiring. This leaves a bright, shiny, clean joint for re-soldering. Solder's lower melting point means that it can be melted away from the base metal, leaving it virtually intact, although the outer layer is "tinned" by the solder. Flux is left behind, which can be easily removed by abrasive or chemical processes. This tinned layer allows the solder to flow to a new connection, resulting in a new connection, and allows the new solder to flow very quickly and easily.

Lead Free Electronic Solder Recent environmental legislation has specifically focused on the widespread use of lead in the electronics industry. The RoHS directives in Europe since July 1, 2006 stipulate that many new electronic circuit boards must be lead-free, mainly in the consumer goods industry but also in some others. In Japan, manufacturers have phased out lead before legislation due to the additional cost of recycling lead-containing products.[22] However, even without the presence of lead, solder can give off fumes that are harmful and/or toxic to humans. It is strongly recommended that equipment be used that can remove fumes from the work area through outdoor ventilation or air filtration.[23] It is a common misconception that lead-free solder requires higher soldering temperatures than lead/tin solder; The wetting temperature in lead/tin solder is higher than the melting point and is the controlling factor: wave soldering can be performed at the same temperature as older lead/tin solder.[22] However, with this effort came many new technical challenges; To lower the melting point of tin-based solder alloys, several new alloys had to be investigated, with copper, silver, and bismuth additives as typical secondary additives to lower the melting point and control other properties. Also, tin is a more corrosive metal and can eventually cause soldering kits etc. to fail. [22]

The lead-free construction has also been extended to components, pins and connectors. Most of these pens used frames made of copper and lead, tin, gold, or other finishes. Tin finishes are the most popular lead-free finishes. However, this raises the question of how to treat tin whiskers. The current movement is taking the electronics industry back to the problems solved in the 1960s with the addition of lead. JEDEC has developed a rating system to help lead-free electronics manufacturers decide what action to take against mustaches based on their application.

Soldering Defects When joining copper tubing, if a joint is not properly heated and filled, a “void” can form. This is usually the result of improper flame placement. If the heat from the flame is not directed at the back of the fitting cup and the solder wire is applied 180 degrees from the flame, the solder will quickly fill the fitting gap and trap some flux in the joint. This bubble of trapped flow is the vacuum; An area within a solder joint where solder cannot completely fill the terminal cup because flux has sealed in the solder joint, preventing solder from filling that space.

Electronics Various problems can arise in the soldering process, which can result in connections not working immediately or after a period of time. The most common mistake in hand soldering is due to the parts being joined not exceeding the temperature of the liquid solder, resulting in a "cold solder joint". This is usually the result of using the soldering iron to heat the solder directly rather than the parts themselves. Done correctly, the iron heats the parts to be joined which in turn melts the solder and provides sufficient heat in the joined parts for complete wetting cares. In electronic hand soldering, flux is incorporated into the solder. Therefore, the initial heating of the solder can cause the flux to evaporate before the surfaces to be soldered are cleaned. A cold-welded connection must not conduct at all or only intermittently. Cold welded joints also occur in mass production and are a common cause of equipment passing tests but failing after a few years of operation. A "dry joint" occurs when the temper solder moves, and usually occurs because the joint moves when the soldering iron is removed from the joint. Improperly selected or applied flux can lead to joint failure. If not properly cleaned, flux can corrode the seal and eventually cause seal failure. Without flux, the joint may not be clean or may oxidize, resulting in a weak joint. Non-corrosive fluxes are commonly used in electronics. Therefore, flux cleaning can be simply a matter of aesthetics or to facilitate visual inspection of joints in specialized "mission-critical" applications such as aerospace, military, and medical devices. For satellites also to reduce the weight a bit, but it makes sense. In high humidity conditions, even a non-corrosive flux can remain slightly active, so the flux can be removed to reduce corrosion over time. In some applications, the circuit board may also be coated with some type of protective material, such as varnish, to protect it and any exposed solder joints from the environment. The movement of the metals to be welded before the weld cools leads to a very unreliable cracked joint. In electronic soldering terminology, this is known as a "dry" joint. It has a characteristic matte or grainy appearance immediately after gluing, instead of being smooth, glossy and glossy. This appearance is caused by crystallization of the liquid solder. A dry spot is mechanically weak and electrically conductive. In general, a good weld is a good joint. As already mentioned, it should be smooth, glossy and shiny. If the solder joint has clumps or balls of light-colored solder, the metal has not been "wetted" properly. If it is not bright and shiny, this indicates a weak and "dry" joint. However, technicians attempting to apply this guideline when using lead-free solder formulations can become frustrated as these types of solders cool easily and acquire a matte finish even with good bonding. Solder appears shiny on melting and suddenly becomes cloudy on solidification, although it was undisturbed on cooling.

Soldering In electronics, a "concave" fillet is ideal. This indicates good wetting and minimal solder consumption (therefore minimal heating of heat-sensitive components). A joint can be good, but if a lot of unnecessary solder is used then obviously more heating is required. Overheating a PCB can cause "delamination", the copper trace can separate from the PCB, especially on single-sided PCBs without a continuous coating.

Tools In principle, any type of soldering tool can do any job with solder at the temperatures it can produce. In practice, different tools are better suited for different applications. Soldering hand tools widely used for electronic work include the electric soldering iron, which can be fitted with a variety of tips ranging from blunt to very fine, to chisel heads for hot cutting plastics in place of soldering. . The simplest irons have no temperature control; Small irons cool down quickly when used to solder a metal case, for example, while large irons have tips that are too fiddly to work on circuit boards and similar fine work. Temperature-controlled irons have a power reserve and can maintain the temperature for a variety of tasks. The soldering gun heats up faster but has a larger and heavier body. Gas cooktops, which use a catalytic tip to heat easily without a flame, are used for portable applications. Hot air guns and pens allow you to rework component packages that are not as easily possible with irons and heat guns. For non-electronic applications, soldering torches use a flame instead of a soldering tip to heat the solder. Soldering torches are usually butane fueled[24] and come in sizes ranging from very small butane/oxygen units suitable for very fine, high-temperature jewelry work, to large oxy-fuel torches suitable for heavy-duty work. , like copper. Pipeline. Conventional general-purpose propane torches of the same type used for paint stripping and pipe de-icing can be used for welding pipe and other fairly large objects with or without a soldering tip attachment. Pipes are usually welded with a torch that directly applies an open flame. A soldering iron is a tool with a large copper head and long handle that is heated in a forge and is used to heat sheets of metal for soldering. Typical solder coppers have heads that weigh between one and four pounds. The head offers a large thermal mass to store enough heat to weld large areas before reheating in the fire is required; The bigger the head, the longer the working time. Soldering irons were once standard body shop tools, although body welding has largely been replaced by spot welding for mechanical connections and non-metallic fillers for contours. Hobbyists have used toaster ovens and portable infrared lights to replicate production welding processes on a much smaller scale. Bristle brushes are typically used to apply flux for plumbing jobs. Flux core solder is typically used for electronic work, but additional flux can be used from a flux pen or dispensed from a small vial with a syringe-like needle. Wire brush, steel wool, and emery cloth are commonly used to prepare plumbing connections for plumbing. Electronic splices are usually made between tinned surfaces and rarely require mechanical cleaning, although conductors from tarnished components and copper traces will show a dark layer of oxide passivation (due to aging), just like a new circuit board. If they are on the shelf for a year or more, they may need to be mechanically cleaned. Some electronic fluxes are designed to be stable and inactive upon cooling and do not require cleaning, although they can still be cleaned if desired, while other fluxes are acidic and must be removed after soldering to prevent circuit corrosion impede. For PCB assembly and reconditioning, alcohol or acetone is used with cotton swabs or bristle brushes to remove flux residue after soldering. Typically, a rough rag is used to remove flux from a plumbing joint before it cools and hardens. A glass fiber brush can also be used. A heat sink such as an alligator clip can be used to prevent damage to heat-sensitive components during hand soldering. The heatsink limits the body temperature of the component by absorbing and dissipating heat (reducing the thermal resistance between the component and the air), while the thermal resistance of the cables maintains the temperature difference between the part of the cable to be soldered and the component. body with it

When soldering, the wires get hot enough to melt the solder while the component body stays cooler.

References [2] [3] [4] [5] [6]

Differences between Brazing and Brazing (http://www.tinmantech.com/html/faq_brazing_versus_soldering.php) Solder Fluxes (http://www.indium.com/products/soldfabrications/fluxes.php) Lot 101: Overview (http:// /www.indium.com/ _dynamo/ download.php?docid=27) IPC-A-610 Revision E Section 10.6.4 AWS A3.0:2001, Standard welding conditions and definitions, including conditions for bonding, brazing, soldering, thermal Cutting and Thermal Spraying, American Welding Society (2001), p. 118. ISBN 0-87171-624-0 [8] Brazing Tips (http://www.bellmanmelcor.com/brazing_tips1.htm) [9] Factors Affecting Joint Strength (http://www.NicrobrazNewsArchives/WCC_Article_Joint_Strength .htm) [10] Properties of solder joints made of gold-nickel alloys in high-temperature materials; Prof. Jakob Colbus and Karl Zimmermann. (http://www.goldbulletin.org/assets/file/ goldbulletin/ downloads/ Colbus_2_7.pdf) [12] 0204 www.coherent.com [13] 070927 ma-info.de [14] 070927 vincenc.com.tw (mentioned as technical) [15] (http://www.plumbingpages.com/featurepages/ Pipeworkfluxsolder.cfm) [16] http://www. Questions. com/html/10/T110211. asp [17] Alumaloy (http://www.alumaloy.net/alumaloy1.htm), retrieved on 04.03.2009 [18] Alumiweld FAQ (http://www.alumaloy1.com/faq.html), retrieved 2009 - 04-03 [19] MIL-R-4208 (http://www.tpub.com/content/logistics/34/39/10/00-580-0585.htm), accessed 2009-04-03 [20 ] Aladdin 3-in-1 (http://www.aladdin3in1.com/catalog.htm) accessed April 3, 2009 [21] HTS-2000 (http://www.aluminiumrepair.com/more_info.asp) accessed on 9 March 2009 [22] FACT AND FICTION IN LEAD-FREE SOLDER (http://www.dklmetals.co.uk/PDF Files/Factorfiction.pdf) from www.dkmetals.co.uk/PDF Files/Factorfiction. pdf) from www.dkmetals. co.uk [23] Dangers of solder fumes (http://www.senryair.com/solder-fumes.htm) [24] What is the definition of a welding torch? (http://www.toolingu.com/definition-660130-28677-soldering-torch.html)

External links • Desoldering Guide (http://www.epemag.wimborne.co.uk/desolderpix.htm) • A short video explanation of how soldering works (http://vega.org.uk/video/programme /166) • RoHS Directive 2002/95/EC (http://europa.eu/eur-lex/pri/en/oj/dat/2003/l_037/l_03720030213en00190023.pdf) – the restriction of the use of certain hazardous substances in electrical equipment and electronic Equipment • A useful table of various liquidus temperatures of solder alloys can be found in an article hosted on the EMPF (http://www.empf.org/empfasis/jan05/lfaudit.htm).

idle

Inert To be inert means to be in a state of doing little or nothing.

Chemistry In chemistry, the term inert is used to describe a substance that is not chemically reactive. Noble gases used to be called inert gases because it was assumed that they did not take part in any chemical reactions. This is because their outer shells of electrons (valence shells) are completely filled, so they have little tendency to gain or lose electrons. It is now known that these gases actually react to form chemical compounds such as xenon tetrafluoride. Therefore, they were renamed noble gases. However, driving such reactions requires a large amount of energy, usually in the form of heat, pressure, or radiation, often with the help of catalysts. The resulting compounds must generally be stored under moisture-free conditions at low temperatures to prevent rapid decomposition into their elements. The term inert can also be used relatively. For example, molecular nitrogen is inert under normal conditions because it exists as a diatomic molecule, N 2 . The presence of a strong triple covalent bond in the N 2 molecule makes it unreactive under normal circumstances. However, even under normal conditions, nitrogen gas reacts with alkali metal lithium to form the compound lithium nitride (Li3N). Under high pressures and temperatures and with the right catalysts, nitrogen becomes more reactive; the Haber process uses such conditions to produce ammonia from atmospheric nitrogen. Inert atmospheres consisting of gases such as argon, nitrogen, or helium are commonly used in chemical reaction chambers and in storage vessels for air- or water-sensitive substances to prevent unwanted side reactions of these substances with air and water.

Pesticides The federal Insecticides, Fungicides and Rodenticides Act divides the ingredients in pesticides into two groups: active and inert. An inert chemical product in this context is one that does not have a toxic effect on the species that the pesticide is intended to control, but does not preclude it from still having biological activity on other species, including toxicity to humans. . "Inert ingredients"[1] in pesticides include solvents, propellants, preservatives.[2] Since 1997, the US Environmental Protection Agency has recommended that pesticide manufacturers label non-active ingredients as "other ingredients" rather than "inert" to avoid misinformation to the public.[2]

Number Theory In the branch of mathematics known as algebraic number theory, a prime ideal is said to be inert if it is still prime when viewed in an extension field. Such a prime could have split as a product of other prime ideals, but since it is inert it remains essentially unchanged.

Ammunition In the field of weapons and explosives, inert ammunition is ammunition in which all energetic materials such as detonators, detonators and explosives or incendiary materials contained therein have been removed or rendered harmless. Inert ammunition is used in military and naval training and is also collected and displayed by public museums or by individuals. See also military doll. US and NATO carrier munitions are usually painted entirely light blue and/or bear the word "INERT" in prominent places.

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References [1] EPA (2010), FIFRA Eligible Inert Ingredients 25(b) Pesticide Products, updated December 20, 2010 (http://www.epa.gov/opprd001/inerts/section25b_inerts.pdf), Office of Prevention, pesticides and toxic substances [2] Inert ingredients in pesticide products (http://www.epa.gov/opprd001/inerts/ ). US Environmental Protection Agency, Office of Pesticide Programs.

Phosphide In chemistry, a phosphide is a compound of phosphorus with one or more less electronegative elements. Binary compounds are formed with most of the less electronegative elements, with the exception of Hg, Pb, Sb, Bi, Te, Po.[1] Typically, there are a number of stoichiometries for each element; For example, potassium has nine phosphides (K3P, K4P3, K5P4, KP, K4P6, K3P7, K3P11, KP10.3, KP15) and nickel has eight (Ni3P, Ni5P2, Ni12P5, Ni2P, Ni5P4, NiP, NiP2, NiP3). [1] The classification of these compounds is difficult.[2] In terms of structure and reactivity, they can be roughly classified[1] as: • mainly ionic with P3– ions. Examples are Group 1 (e.g. Na 3 P) and Group 2 (e.g. Ca 3 P 2 ) metal phosphides. • Polyphosphides with, for example, P4-2 dumbbell ions; group P3− 11 ions; Polymer chain anions (e.g. the helical (P-)n ion) and complex sheets or three-dimensional anions. • Compounds with single P atoms in a metal lattice whose electrical conductivity can range from semiconducting (eg GaP) to metallic (eg TaP).[3] Two polyphosphide ions, P4− 3 in K 4P 3 and P5− 4 in K P , are radical anions with an odd number of valence electrons that render both 5 4 compounds paramagnetic.[1]

Production There are many ways to produce phosphide compounds. The most general and common way to do this is to heat the metal to be joined with phosphorus and red phosphorus (P) under inert atmospheric conditions or under vacuum. In principle, all metal phosphides and polyphosphides can be synthesized from elemental phosphorus and the respective metallic element in stoichiometric forms. However, the synthesis is complicated due to several problems. Exothermic reactions are usually explosive due to local overheating. Oxidized metals, or even just an oxidized layer on the outside of the metal, require extreme and unacceptably high temperatures to initiate phosphorization.[4] Hydrothermal reactions to generate nickel phosphides produced pure and well-crystallized nickel phosphide compounds, Ni2P and Ni12P5. These compounds were synthesized by solid–liquid reactions between NiCl2∙12H2O and red phosphorus at 200 °C for 24 and 48 hours, respectively.[5]

Phosphor

Examples • • • • •

Aluminiumphosphid (AlP) Indiumphosphid (InP) Calciumphosphid (Ca3P2) Kupferphosphid (Cu3P) Magnesiumphosphid (Mg3P2)

Natural Examples Schreibersite (Fe,Ni)3P is a common mineral in some meteorites.[6][7]

References [1] H.G. Von Schnering, W. Hönle Phosphores - Solid State Chemistry Encyclopedia of Inorganic Chemistry Ed. R. Bruce King (1994) John Wiley & Sons ISBN 0-471-93620-0 [6] Handbook of Mineralogy (http://www.handbookofmineralogy.com). )

Nickel

Nickel Nickel Ni 28

cobalt ← nickel → copper ↑

Ni ↓ Pd Nickel on the Periodic Table Shiny, metallic, silvery appearance with golden tinges

General Properties Name, Symbol, Number

Nickel, Nickel,

pronunciation

/ˈnɪkəl/ NIK-mano

item category

transition metal

group, period, block

10, 4, too

standard atomic weight

58.6934(4)(2)

Nickel

39 Electronic configuration

[Ar] 4s2 3d8 or [Ar] 4s1 3d9 (see text) 2, 8, 16, 2 or 2, 8, 17, 1

discovery of history

Axel Fredrik Cronstedt (1751)

first isolation

Axel Fredrik Cronstedt (1751) Propriedades físicas

Phase

fest

Density (near room temperature)

8,908 g·cm−3

Density of the liquid in m.p.

7,81 g·cm−3

fusion point

1728K, 1455°C, 2651°F

boiling point

3186K, 2913°C, 5275°F

heat of fusion

17.48 kJ·mol−1

heat of vaporization

377.5 kJ·mol-1

molar heat capacity

26.07 J mol-1 K-1 vapor pressure

P (Pa)

100

1 k

10 thousand 100 thousand

at T (K) 1783 1950 2154 2410 2741 3184 Atomic properties [1]

[2]

oxidation states

4, 3, 2, 1, -1 (slightly basic oxide)

electronegativity

1.91 (Pauling Scale)

Ionization energies (more)

1°: 737.1 kJ·mol−1 2°: 1753.0 kJ·mol−1 3°: 3395 kJ·mol−1

Atomic func

124 hours

covalent ray

124±16h

Radio Van der Waals

163h Miscellaneous

Nickel

40 crystalline structure

face-centered cubic

magnetic request

ferromagnetic

Electrical resistance

(20 °C) 69,3 nΩ·m

thermal conductivity

90,9 W·m−1·K−1

thermal expansion

(25 °C) 13,4 µm·m−1·K−1

Speed of sound (thin bar) (r.t.) 4900m s−1 Modulus of elasticity

200 GPa

Schneidmodul

76 GPa

Volumenmodul

180 GPa

poison ratio

0,31

Mohs hardness

4.0

Dureza Vickers

638 MPa

Brinell hardness

700 MPa

CAS registration number

7440-02-0 Stabilste Isotope

Main article: Nickel isotopes iso

THE

half-life

DM OF (MeV)

Ni 68.077% >7×1020e β+β+

58 59

path

Al 26.223 %

60 61

1,14%

TO 3.634 %

62 63

sin

Al 0,926 %

7.6 × 104 years

1,9258

trust

company

Ni is stable with 32 neutrons

Ni is stable with 33 neutrons

Ni is stable with 34 neutrons

100.1 years

b−

0,0669

copper

Ni is stable with 36 neutrons

Nickel is a chemical element with the chemical symbol Ni and atomic number 28. It is a lustrous, silvery-white metal with a slight gold tinge. Nickel belongs to the transition metals and is hard and ductile. Pure nickel exhibits significant chemical activity, which can be observed when nickel is sprayed to maximize exposed surface area for reactions to take place, but larger portions of the metal slowly react with air under ambient conditions due to the formation of a protective oxide. Pop up. Despite this, nickel is so reactive with oxygen that native nickel is rarely found on Earth's surface, being mainly confined to the interiors of the largest nickel-iron meteorites, which were shielded from radiation and oxidation during their time in space. On Earth, this native nickel is always found in combination with iron, reflecting the origin of these elements as major end products of supernova nucleosynthesis. A mixture of iron and nickel is believed to make up the Earth's inner core.[3] The use of nickel (as a natural nickel-iron meteoric alloy) dates back to 3500 BC. back. Nickel was first isolated and classified as a chemical element in 1751 by Axel Fredrik Cronstedt, who initially confused its mineral with a

copper-nickel ore. The element's name comes from a mischievous spirit in German mining mythology, Nickel (similar to Old Nick), who embodied the fact that copper-nickel ores resisted refining into copper. An economically important source of nickel is limonite iron ore, which generally contains 1-2% nickel. Other important nickel minerals are garnierite and pentlandite. Major manufacturing bases include the Sudbury region of Canada (believed to be meteoric in origin), New Caledonia in the Pacific, and Norilsk in Russia. Because of nickel's slow rate of oxidation at room temperature, it is considered resistant to corrosion. Historically, this has led to its use for plating metals such as iron and brass, its use for chemical devices, and its use in certain alloys that retain a high silver polish, such as silver. B. German silver. Approximately 6% of world nickel production is still used for plating corrosion resistant pure nickel. Nickel was once a common component of coins, but has been largely replaced by cheaper iron for this purpose, especially since the metal is an allergen to some people's skin. Despite objections from dermatologists, it was reintroduced on British coins in 2012. [ ] Nickel is one of four elements that are ferromagnetic at room temperature. Partial nickel based alnico permanent magnets have an intermediate strength between iron based permanent magnets and rare earth magnets. The metal is valuable in the modern world primarily because of the alloys it forms; About 60% of world production is used for nickel steels (especially stainless steel). Other common alloys, as well as some new super alloys, account for the majority of nickel consumption in the rest of the world, with chemical uses of nickel compounds consuming less than 3% of production. [ ] As a compound, nickel has several chemical manufacturing niches. used as a catalyst for hydrogenation. The enzymes of some microorganisms and plants contain nickel as an active site, making the metal an essential nutrient for them.

Properties Atomic and Physical Properties Nickel is a silvery white metal with a slight golden hue that requires a mirror finish. It is one of four elements that are magnetic at or near room temperature, the others being iron, cobalt, and gadolinium. Its Curie temperature is 355 °C, which means that bulk nickel is not magnetic above this temperature.[4] The nickel unit cell is a face-centered cube with a lattice parameter of 0.352 nm, giving an atomic radius of 0.124 nm. Nickel belongs to the transition metals and is hard and ductile. Controversy over the electron configuration The nickel atom has two electron configurations, [Ar] 4s2 3d8 and [Ar] 4s1 3d9, which are energetically very similar, with the symbol [Ar] referring to the central structure similar to argon. There is some disagreement as to what the lowest power setting should be.[6] Chemistry textbooks give the electronic configuration of nickel as [Ar] 4s2 3d8[5] or equivalently as [Ar] 3d8 4s2.[6] This configuration conforms to Madelung's power order rule, which predicts that 4s will fill before 3d. This is supported by the experimental fact that the lowest energy state of the nickel atom is a 4s2 3d8 energy level, specifically the 3d8(3F) 4s2 3F, J=4 level.[7] However, each of these two configurations leads to a range of states at different energies.[7] The two sets of energies overlap, and the average energy of the states with the [Ar] 4s1 3d9 configuration is actually less than the average energy of the states with the [Ar] 4s2 3d8 configuration. For this reason, in the research literature on atomic calculations, the ground-state configuration of nickel is given as 4s1 3d9.[6]

Nickel

Isotopes Natural nickel consists of 5 stable isotopes; 58Ni, 60Ni, 61Ni, 62Ni and 64Ni, with 58Ni being the most abundant (68.077% of natural abundance). 62Ni is the most stable nuclide of all existing elements, with a higher binding energy than 56Fe, which is often mistakenly called the most stable, and 58Fe.[8] Eighteen radioisotopes have been characterized, the most stable being 59Ni with a half-life of 76,000 years, 63Ni with a half-life of 100.1 years, and 56Ni with a half-life of 6,077 days. All of the remaining radioactive isotopes have half-lives less than 60 hours, and most of them have half-lives less than 30 seconds. This element also has a metastate. [ ] Nickel-56 is produced by the silicon combustion process and then released in large quantities in Type Ia supernovae. The shape of the light curve of these intermediate to late supernovae corresponds to the electron capture decay from nickel-56 to cobalt-56 and finally to iron-56. [ ] Nickel-59 is a long-lived cosmogenic radionuclide with a half-life of 76,000 years. 59Ni has found many applications in isotopic geology. 59Ni has been used to date meteorites and to determine the abundance of extraterrestrial dust in ice and sediments. Nickel-60 is the by-product of the extinct radionuclide 60Fe, which decays with a half-life of 2.6 million years. Because 60Fe has such a long half-life, its persistence in Solar System materials at sufficiently high concentrations may have resulted in observable variations in the isotopic composition of 60Ni. Therefore, the abundance of 60Ni in extraterrestrial material may shed light on the origin of the solar system and its early history. Nickel-62 has the highest binding energy per nucleus of any isotope for any element (8.7946 MeV/nucleon).[9] Isotopes heavier than 62Ni cannot be formed by nuclear fusion without energy loss. 48Ni, discovered in 1999, is the most proton-rich isotope of a heavy element known. With 28 protons and 20 neutrons, 48Ni is "double magic" (like 208Pb) and therefore exceptionally stable. The half-life of nickel-78 was recently measured to be 110 milliseconds, and it is believed to be an important isotope in supernova nucleosynthesis of elements heavier than iron.[11]

Occurrence On Earth, nickel is most commonly found in combination with sulfur and iron in pentlandite, with sulfur in millerite, with arsenic in the mineral nickel, and with arsenic and sulfur in bright nickel.[12] Nickel is commonly found in iron meteorites such as kamacite and taenite alloys.

Widmanstätten pattern showing the two forms of nickel-iron, kamacite and taenite, in an octahedrite meteorite

Most nickel mined comes from two types of ore deposits. The first are the laterites, where the main minerals are nickel-bearing limonite: (Fe,Ni)O(OH) and garnierite (a hydrated nickel silicate): (Ni,Mg)3Si2O5(OH)4. The latter are magmatic sulphide deposits where the main mineral is pentlandite: (Ni,Fe)9S8. Australia and New Caledonia have the highest estimated reserves (45% combined).[]

In terms of world resources, identified land resources averaging 1% nickel or greater contain at least 130 million tonnes of nickel (approximately double the known reserves). About 60% is in laterites and 40% in sulphide deposits. [] Based on geophysical evidence, it is postulated that most of the nickel on Earth is concentrated in the Earth's outer and inner core. Kamazite and Taenite are natural alloys of iron and nickel. Kamacite typically has an alloy ratio of 90:10 to 95:5, although impurities such as cobalt or carbon may be present, while taenite has a nickel content of between 20% and 65%. Kamacite and taenite are found in nickel-iron meteorites.[13]

Nickel

Compounds The most common oxidation state of nickel is +2, but compounds of Ni0, Ni+, and Ni3+ are well known, and Ni4+ has been demonstrated.[]

Nickel(0) tetracarbonyl nickel (Ni(CO)4), discovered by Ludwig Mond,[] is a volatile liquid and highly toxic at room temperature. When heated, the complex breaks down again into nickel and carbon monoxide: Ni(CO)4

A + 4CO

Nickeltetracarbonyl

This behavior is exploited in the Mond process to purify nickel as described above. The related nickel(0)bis(cyclooctadiene)nickel(0) complex is a useful catalyst in organonickel chemistry because of the readily displaceable cod ligand.

Nickel(I) Nickel(I) compounds and complexes are rare. The diamagnetic dark red K4 [Ni2(CN)6] is a representative example of Ni(I). It is made by reducing K2[Ni2(CN)6] with sodium amalgam. This compound is unstable and releases H2 gas from water.[]

[]

Structure of [Ni2(CN)6]2-Ions

Nickel (II)

Color of various Ni(II) complexes in aqueous solution. From left to right: [Ni(NH3)6]2+, [Ni(en)3]2+, [NiCl4]2-, [Ni(H2O)6]2+

Nickel(II) forms compounds with all common anions, ie sulfide, sulfate, carbonate, hydroxide, carboxylates and halides. Nickel(II) sulfate is produced in large quantities by dissolving nickel metal or oxides in sulfuric acid. It exists as hexa- and heptahydrate.[14] This connection is suitable for galvanic nickel plating.

All four halogens form nickel compounds, all of which adopt octahedral geometries. Nickel(II) chloride is the most common and its behavior is exemplary of the other halides. Nickel(II) chloride is produced by dissolving nickel residues

Nickel

Nickelsulfatkristalle

Hydrochloric acid. The dichloride is usually found as the green hexahydrate, but it can be dehydrated to give the yellow anhydrous NiCl2. Some four-coordinate nickel(II) complexes form tetrahedral and square-planar geometries. Tetrahedral complexes are paramagnetic and planar square complexes are diamagnetic. This equilibrium and the formation of octahedral complexes is in contrast to the behavior of the divalent complexes of the heaviest Group 10 metals, palladium(II) and platinum(II), which tend to adopt only square-planar complexes. []

Nickelocene is known; it has an electron count of 20, making it relatively unstable.

Nickel (III) and (IV)

nickel antimony (III)

For simple compounds, nickel(III) and nickel(IV) occur only with fluorine and oxides, with the exception of KNiIO6, which can be considered as a formal salt of the [IO6]5 ion. []Ni(IV) is present in the mixed oxide BaNiO3 while Ni(III) is present in nickel(III) oxide used as cathode in many rechargeable batteries including nickel-cadmium, nickel-iron, nickel-hydrogen and nickel-metal hydride, and used by some lithium-ion battery manufacturers.[15] Nickel(III) can be stabilized by σ-donor ligands such as thiols and phosphines.[]

History Because nickel ores can easily be confused with silver ores, knowledge of this metal and its uses dates back to very recent times. However, the inadvertent use of nickel is ancient, dating back to 3500 BC. back. Bronzes from today's Syria contained up to 2% nickel.[16] In addition, there are Chinese manuscripts that indicate that between 1700 and 1400 B.C. "White copper" (cupronickel, known as baitong) was used. This Paktong white copper was exported to Britain as early as the 17th century, but the nickel content of this alloy was not discovered as a copper ore until 1822. . However, when the miners failed to extract copper from it, they accused a mischievous goblin from German mythology, Nickel (similar to old Nick), of bullying the copper. They named this mineral Kupfernickel from German Kupfer for copper. In 1751, Baron Axel Fredrik Cronstedt attempted to extract copper from cupronickel and instead produced a white metal that gave its name to the eponymous spirit nickel.[18] In modern German, copper-nickel or copper-nickel refers to the copper-nickel alloy. After its discovery, the only source of nickel was the rare cupronickel, but from 1824 nickel was being extracted as a by-product in the manufacture of cobalt blue. The first major nickel producer was Norway, which mined nickel-rich pyrrhotite from 1848. The introduction of nickel into steel production in 1889 increased the demand for nickel, and the nickel deposits in New Caledonia discovered in 1865 provided most of the world supply between 1875 and 1915. The discovery of large deposits in the Sudbury Basin, Canada, 1883, at Norilsk -Talnakh, Russia, 1920, and at Merensky Reef, South Africa, 1924 enabled the large-scale production of nickel. []

Nickel

Nickel has been part of coins since the mid-19th century. In the United States, the term "nickel" or "nick" was originally applied to the copper-nickel flying eagle penny, which replaced copper with 12% nickel between 1857 and 1858, then out between 1859 and the Indian Head penny the same alloy in 1864. Later still, in 1865, the term came to denote the three-cent nickel, increasing the nickel to 25%. In 1866, the nickel-nickel shield (25% nickel, 75% copper) took over the designation. Along with the alloy ratio, this term has previously been used in the United States. Almost pure nickel coins were first used in 1881 for Dutch pure nickel coins in Switzerland, and most importantly, 99.9% nickel-nickel was minted in Canada (the world's largest nickel producer). Years from 1922 to 1981, and their metal content made these coins magnetic.[19] During the 1942–1945 wartime period, most or all nickel was removed from Canadian and US coins due to the critical use of nickel in armor. ceased manufacturing pure nickel "Nickel" in 1981, reserving the 99.9% pure nickel alloy after 1968 for only the highest denomination coins. Finally, in the 21st century, as nickel prices soar, most countries that previously used nickel in their coins have abandoned the metal due to cost concerns, and the US nickel remains one of the few coins that still uses the metal for anything other than abroad use . plated.[21]

world production

World nickel production in tons, 2005. The largest producer is the Russian Federation, followed by Canada.

[]

Mine Production and Reserves

2010

2011

Australia

170.000

180.000 24.000.000

botsuana

28.000

32.000

490.000

Brazil

59.100

83.000

8.700.000

You have

158.000

200.000

3.300.000

porcelain

79.000

80.000

3.000.000

Colombia

72.000

720.000

Because

70.000

74.000

5.500.000

14.000

1.000.000

232.000

230.000

3.900.000

15.000

25.000

1.600.000

Dominican Republic Indonesia Madagascar

reservations

Nickel

46 in Neucaledonia

130.000

140.000 12.000.000

Filipinas

173.000

230.000

1.100.000

Russia

269.000

280.000

6.000.000

South Africa

40.000

42.000

3.700.000

Other countries

99.000

100.000

4.600.000

World total (metric tons, rounded) 1,590,000 1,800,000 80,000,000

In 2011, Russia was the top nickel producer with about a fifth of the world's share, closely followed by Canada, Australia and Indonesia and the Philippines, according to the US Geological Survey. [] The largest nickel deposits in the non-Russian countries of Europe are in Finland, and the second largest in Greece. A nickel deposit was mined in western Turkey, this location is particularly favorable for foundries, steelworks and European factories. Land resources identified averaging 1% nickel or greater contain at least 130 million tonnes of nickel. About 60% is in laterites and 40% in sulphide deposits. In addition, extensive seafloor nickel resources are found in manganese crusts and nodules covering large areas of the seafloor, particularly in the Pacific Ocean. [ ] The only place in the United States where nickel has been mined commercially is Riddle, Oregon, which hosts several square miles of surface occurrences of nickel-bearing garnierite. The mine closed in 1987.[22][23] The Eagle Mine Project is a proposed new nickel mine in Michigan's Upper Peninsula.

Extraction and purification Nickel is obtained by extractive metallurgy. Nickel is extracted from its ores through traditional roasting and reduction processes that produce a metal with a purity in excess of 75%. In many stainless steel applications, 75% pure nickel can be used without further purification, depending on the composition of the impurities. Most sulfide ores have traditionally been processed using pyrometallurgical techniques to produce a rock for further refining. Recent advances in hydrometallurgy have resulted in significant nickel purification using these processes. Most sulphide showings have traditionally been processed by concentration through a flotation process followed by pyrometallurgical pickling. In hydrometallurgical processes, nickel sulfide ores are subjected to flotation (differential flotation at a very low Ni/Fe ratio) and then smelted. After the production of the nickel mat, it is further processed using the Sherritt-Gordon process. First, the copper is removed by the addition of hydrogen sulfide, leaving a concentrate of only cobalt and nickel. A solvent extraction is then used to separate cobalt and nickel, with a final nickel concentration in excess of 99%.

Electrorefining A second common form of further refining involves leaching the metal matte into a nickel salt solution, followed by electrowinning the nickel from the solution, depositing it as electroless nickel on a cathode.

Electrolytically refined nickel nodules with green crystallized nickel electrolyte salts visible in the pores.

Nickel

overall process

High purity nickel spheres manufactured using the Mond process.

The purification of nickel oxides to obtain the purest metal is done using the Mond process, which increases the nickel concentrate to a purity of over 99.99%.[24] This process was patented by L. Mond and has been used industrially since the beginning of the 20th century. Here, nickel reacts with carbon monoxide at about 40 to 80 °C in the presence of a sulfur catalyst to form nickel carbonyl. Iron also gives pentacarbonyl iron, but this reaction is slow. If necessary, it can be separated by distillation. Dicobalt octacarbonyl is also formed in this process, but this decomposes to tetracobalt dodecacarbonyl at the reaction temperature, giving a non-volatile solid.[ ]

Nickel is derived from nickel carbonyl by one of two processes. It can pass through a large, high-temperature chamber in which tens of thousands of nickel globules, so-called granules, are constantly agitated. It then decomposes and deposits pure nickel on the nickel spheres. Alternatively, nickel carbonyl can be decomposed in a smaller chamber at 230°C to produce a fine nickel powder. The resulting carbon monoxide is recycled and reused throughout the process. The high-purity nickel produced by this process is known as "carbonyl nickel".[25]

Metal Value The market price of nickel skyrocketed throughout 2006 and the first few months of 2007; On April 5, 2007, the metal was trading at $52,300/ton or $1.47/ounce. The US nickel coin contains 0.04 ounces (1.25 g) of nickel, which was worth 6.5 cents at April 2007 prices, along with 3.75 grams of copper, worth about 3 cents, making the metal more than 9 is worth cents. Since the face value of a nickel is 5 cents, it's an attractive target for smelters for people who want to sell the metals for a profit. However, the United States Mint anticipated this practice and introduced new interim rules on December 14, 2006, subject to a 30-day public comment, making it a crime to issue and export pennies and nickels.[26] Violators may be subject to a fine of up to $10,000 and/or imprisonment for a maximum of five years. On September 16, 2011, the melting point of a US nickel was $0.0600409, 20% higher than face value.[27]

Applications The proportion of world nickel production currently used for various applications is as follows: 46% for the manufacture of nickel steel; 34% in non-ferrous alloys and super alloys; 14% electroplating and 6% for other uses. [][] Nickel is used in many specific and recognizable industrial and consumer products including stainless steel, alnico magnets, coins, rechargeable batteries, electric guitar strings, pickups, microphones and specialty alloys. . It is also used for electroplating and as a nickel superalloy (RB199) for green-on-glass jet engine turbine blades. Nickel is primarily an alloying metal, its main uses being in nickel steels and nickel castings, of which there are many varieties. It is also used in many other alloys such as nickel, brass, and bronze, and in alloys with copper, chromium, aluminum, lead, cobalt, silver, and gold (Inconel, Incoloy, Monel, Nimonic).[28]

Nickel

48 Because of its resistance to corrosion, nickel has sometimes been used in the past as a substitute for decorative silver. Nickel was also occasionally used as a cheap coinage metal in some countries after 1859 (see above), but was mostly replaced by cheaper stainless steel (i.e. ferrous) alloys in the latter years of the 20th century, except mainly in the United States. US.

A "horseshoe magnet" made of a nickel-alnico alloy. The composition of alnico alloys is typically 8-12% Al, 15-26% Ni, 5-24% Co, up to 6% Cu, up to 1% Ti, the balance is Fe. Alnico development began in 1931 when it was discovered that an alloy of iron, nickel and aluminum had a coercivity twice that of the best magnetic steels of the time. Alnico magnets are now being replaced by rare earth magnets in many applications.

Nickel is an excellent alloying agent for other precious metals, which is why it is used in the so-called fire test as a collector of platinum group elements (PGE). As such, Nickel is capable of fully collecting all 6 PGE elements from ores as well as partially collecting gold. High-yield nickel mines may also be involved in the production of PGE (mainly platinum and palladium); Examples are Norilsk in Russia and the Sudbury Basin in Canada. Nickel foam or nickel mesh are used in gas diffusion electrodes for alkaline fuel cells.[29][30] Nickel and its alloys are widely used as catalysts for hydrogenation reactions. Raney nickel, a finely divided alloy of nickel and aluminum, is a common form; however, related catalysts are also commonly used, including "Raney-type" catalysts.

Nickel is an inherently magnetostrictive material, which means that the material will undergo a small change in length in the presence of a magnetic field.[31] For nickel, this change in length is negative (material contraction), known as negative magnetostriction, and is of the order of 50 ppm. Nickel is used as a binder in the cemented carbide or cemented carbide industry and is used in proportions of 6 to 12% by weight. Nickel can make tungsten carbide magnetic and impart corrosion-resistant properties to cemented tungsten carbide parts, although the hardness is lower than parts made with cobalt binder.[32]

Biological Role Although not recognized until the 1970s, nickel plays an important role in the biology of microorganisms and plants.[33][34] The plant enzyme urease (an enzyme that helps hydrolyze urea) contains nickel. In addition to iron and sulfur groups, NiFe hydrogenases also contain nickel. Such [NiFe]hydrogenases characteristically oxidize H2. A nickel tetrapyrrole coenzyme, Cofactor F430, is present in methyl coenzyme M reductase that drives methanogenic archaea. One of the carbon monoxide dehydrogenase enzymes consists of an Fe-Ni-S cluster.[35] Other nickel-containing enzymes include a rare bacterial class of superoxide dismutase [36] and glyoxalase I enzymes in bacteria and various parasitic eukaryotic trypanosomal parasites [37] (this enzyme in higher organisms, including yeast and mammals, uses divalent zinc, Zn2+). [][][38][39][40]

Toxicity In the US, the minimum risk level for nickel and its compounds is set at 0.2 µg/m3 for inhalation for 15 to 364 days.[41] Nickel sulfide fumes and dust are believed to be carcinogenic, and several other nickel compounds may also be carcinogenic.[42][43] Nickel carbonyl, [Ni(CO)4], is an extremely toxic gas. The toxicity of metallic carbonyls is a function of both the toxicity of the metal and the ability of the carbonyl to give off highly toxic carbon monoxide gas, and this is no exception; Carbonyl nickel is also explosive in air.[44][45] Sensitized individuals may have a nickel allergy that affects the skin, also known as dermatitis. Nickel sensitivity may also be present in patients with

Pompholyx Nickel. Nickel is a leading cause of contact allergies, in part due to its use in jewelry for pierced ears.[46] Nickel allergies affecting pierced ears are often characterized by itching and redness of the skin. Because of this problem, many earrings are now made without nickel. The allowable amount of nickel in products that come into contact with human skin is regulated by the European Union. In 2002, researchers found levels of nickel emitted from €1 and €2 coins well above these standards. This is believed to be due to a galvanic reaction.[47] Nickel was named allergen of the year in 2008 by the Contact Dermatitis Society of America.[48] The reports also showed that both nickel-induced hypoxia-inducible factor (HIF-1) activation and upregulation of hypoxia-inducible genes are due to a reduction in intracellular ascorbate levels. The addition of ascorbate to the culture medium increased the level of intracellular ascorbate and reversed the metal-induced stabilization of HIF-1 and HIF-1α-dependent gene expression.[49][50]

References [5] G.L. Miessler and DA Tarr, "Inorganic Chemistry" (2nd ed., Prentice-Hall 1999), p.38 [6] R.H. Petrucci et al. "General Chemistry" (8th ed., Prentice-Hall 2002) p.950 [7] NIST Atomic Spectrum Database (http://physics.nist.gov/PhysRefData/ASD/levels_form.html) For reading levels B. the nickel atom, enter "Ni I" in the "Spectrum" field and click "Get Data". [8] Fewell, M. P. The atomic nuclide with the highest average binding energy. American Journal of Physics 63(7): 653–58. . URL: http://adsabs. Harvard. edu/abs/1995AmJPh. . 63. . 653F. Accessed: 2011-03-22. (Archived by WebCite® at http://www.webcitation.org/5xNHry2gq) [12] National Pollutant Inventory - Nickel and Compounds Fact Sheet (http://www.npi.gov.au/substances/nickel/index.html ). npi.gov.au. Accessed 09/01/2012. [14] Keith Lascelles, Lindsay G. Morgan, David Nicholls, Detmar Beyersmann "Nickel Compounds" in Ullmann's Encyclopedia of Industrial Chemistry 2005, Wiley-VCH, Weinheim. [17] Chambers Twentieth Century Dictionary, p. 888, W&R Chambers Ltd, 1977. [20] Canada used nickel plating on its nickels in 1945 [21] (http://realcent.forumco.com/topic.asp?TOPIC_ID=15946 ) partial list of world coins that used nickel. [26] United States Mint Moves to Limit Export and Melting of Coins (http://www.usmint.gov/pressroom/index.cfm?action=press_release& ID=724), United States Mint United States, press release, December 14 , 2006 [31] UCLA: Overview of Magnetostrictive Materials (http://aml.seas.ucla.edu/research/areas/magnetostrictive/Overview.htm). Aml.seas.ucla.edu. Accessed 09/01/2012. [34] E-Book ISBN 978-94-007-5561-1 E-Book[41] ToxGuideTM for Nickel (http://www.atsdr.cdc.gov/toxguides/toxguide-15.pdf). US Department of Health and Human Services Agency for Toxic Substances and Disease Registry

External Links • Nickel (http://www.periodicvideos.com/videos/028.htm) on Periodic Table of Videos (University of Nottingham) • CDC – Nickel – NIOSH Health and Safety Topic (http://www.cdc.gov/niosh/ topics/nickel/) • An occupational hygiene assessment of exposure to dermal nickel in the primary manufacturing industry (http://www.iom-world.org/pubs/IOM_TM0405.pdf) by GW Hughson. Institute for Occupational Medicine Research Report TM/04/05 • An occupational hygiene assessment of exposure to dermal nickel in the primary production and consumer industries. Phase 2 report (http://www.iom-world.org/pubs/IOM_TM0506.pdf) by GW Hughson. Institute for Occupational Health Research Report TM/05/06 • Norilsk Nickel, Norilsk, Russia (http://www.nornik.ru/en/) • Vale Nickel, Sudbury, Ontario, Canada (formerly known as INCO) ( http: / /nickel.vale.com/countries/canada/sudbury/default.aspx) • Xstrata Nickel, Sudbury Operations (formerly known as Falconbridge) (http://www.xstratanickel.com/EN/Operations/Pages/SudburyOperations .aspx )

Lead

Diaper Diaper Pb 82

Thallium ← Lead → BismuthSn ↑

Pb ↓ Fl Lead on the periodic table Metallic gray appearance

General Properties Name, Symbol, Number

Blei, Blei, 82

pronunciation

/lɛd/ LED

item category

Metal weapons

group, period, block

14, 6, p.

standard atomic weight

207.2

Lead

51 Electronic configuration

[Vehicle] 4f14 5d10 6s2 6p2 2, 8, 18, 32, 18, 4

discovery of history

Middle East (7000 BC) Physical Properties

Phase

fest

Density (near room temperature)

11,34 g·cm−3

Density of the liquid in m.p.

10,66 g·cm−3

fusion point

600,61 K, 327,46 °C, 621,43 °F

boiling point

2022K, 1749°C, 3180°F

heat of fusion

4.77 kJ·mol-1

heat of vaporization

179.5 kJ·mol-1

molar heat capacity

26,650 J mol-1 K-1 vapor pressure

P (Pa)

100

1 k

10 thousand 100 thousand

in T (K) 978 1088 1229 1412 1660 2027 Atomic Properties Oxidation States

4, 3, 2, 1 (amphoteres Oxid)

electronegativity

1.87 (Pauling Scale)

ionization energies

1st: 715.6 kJ mol-1 2nd: 1450.5 kJ mol-1 3rd: 3081.5 kJ mol-1

Atomic func

175 hours

covalent ray

146±17h

Radio Van der Waals

202h Miscellaneous

Lead

52 crystal structure

face-centered cubic

magnetic request

diamagnetic

Electrical resistance

(20 °C) 208 nΩ·m

thermal conductivity

35,3 W·m−1·K−1

thermal expansion

(25 °C) 28,9 µm·m−1·K−1

Speed of sound (thin bar) (r.t.) (annealed) 1190m s−1 Modulus of elasticity

16 GPa

Schneidmodul

5,6 GPa

Volumenmodul

46 GPa

poison ratio

0,44

Mohs hardness

1,5

Brinell hardness

5,0 HB = 38,3 MPa

CAS registration number

7439-92-1 Stabilste Isotope

Main article: Isotopes of lead iso

THE

Diapers 1.4%

204 205

sin

half-life

1.972

200

0,051

205

1.53×107 years 206

Diapers 22.1%

207

>1.4 × 1017 years

Diapers 24.1%

206

DM OF (MeV)

HgTl

Pb is stable at 124 neutrons Pb is stable at 125 neutrons

Diapers 52.4%

>2×1019 years

0,5188

204

bp-Spur

22.3 years

3.792

206

b−

0,064

210

208 210

Hg-Hg-Bi

Lead is a chemical element of the carbon group with the symbol Pb (from Latin: plumbum) and atomic number 82. Lead is a soft and malleable metal that is considered a heavy and bad metal. Metallic lead is bluish-white in color when freshly cut, but soon becomes a dull grayish color when exposed to air. Lead has a brilliant chrome-silver luster when melted in a liquid. Lead is used in construction, lead-acid batteries, bullets, weights, solder, tin, fusible alloys, and radiation protection. Lead has the highest atomic number of any stable element, although the second highest element, bismuth, has such a long half-life (much longer than the age of the universe) that it can be considered stable. Its four stable isotopes all have 82 protons, a magic number in the nuclear shell model of atomic nuclei. Lead is a toxic substance to animals, including humans, at certain levels of contact. It damages the nervous system and causes brain disorders. Excess lead also causes blood disorders in mammals. as an item

Lead

Like mercury, another heavy metal, lead is a neurotoxin that accumulates in both soft tissue and bone. Lead poisoning has been documented as far back as ancient Rome, ancient Greece, and ancient China.

Properties Lead is a lustrous, silvery metal with a faint blue tinge in a dry atmosphere.[1] Upon contact with air, it begins to darken and, depending on the conditions, forms a complex mixture of compounds. The color of the compounds may vary. The colored layer can contain significant amounts of carbonates and hydroxycarbonates.[2][3] It has some distinctive properties: high density, softness, ductility and malleability, low electrical conductivity compared to other metals, high corrosion resistance, and the ability to react with organic chemicals.[1] Various traces of other metals change its properties significantly: adding small amounts of antimony or copper to lead increases the hardness of the newly solidified (molten) lead alloy and improves its resistance to corrosion by sulfuric acid.[1] Some other metals also only improve hardness and fight metal fatigue, such as cadmium, tin, or tellurium; Metals such as sodium or calcium also have this ability, but they weaken chemical stability.[1] Finally, zinc and bismuth simply reduce corrosion resistance (0.1% bismuth content is the limit for industrial use).[1] In contrast, lead contamination degrades the quality of industrial materials, although there are exceptions: for example, small amounts of lead improve the ductility of steel.[1] Lead has only one common allotrope, which is face-centered cubic with a lead-to-lead distance of 349 pm.[4] At 327.5 °C (621.5 °F)[5] lead melts; the melting point is higher than that of tin (232 °C, 449.5 °F)[5] but significantly lower than that of germanium (938 °C, 1721 °F).[6] The boiling point of lead is 1749 °C (3180 °F),[7] which is lower than that of tin (2602 °C, 4716 °F)[5] and germanium (2833 °C, 5131 °F). 6 ] The densities increase in the group: The values of Ge and Sn (5.23[8] and 7.29 g cm−3,[9] respectively) are well below lead: 11.32 g cm−3 .[8th] A lead atom has 82 electrons with an electron configuration of [Xe]4f145d106s26p2. In its compounds, lead (unlike the other group 14 elements) normally loses its two outer electrons instead of four and becomes lead(II) ions, Pb2+. This unusual behavior is explained by considering the inert pair effect, which occurs due to the stabilization of the 6s orbital due to relativistic effects, which are stronger near the end of the periodic table.[10] Tin shows a weaker effect: tin(II) is still a reducing agent.[10] Electrode potential numbers show that lead is only slightly more easily oxidized than hydrogen. Therefore, lead can be dissolved in acids, but this is often not possible due to specific problems (e.g. formation of insoluble salts).[11] Powdered lead burns with a bluish-white flame. As with many metals, finely divided lead powder shows pyrophoricity.[12] Toxic fumes are released when lead is burned.

Isotopes Lead occurs naturally on earth only in the form of four isotopes: lead-204, -206, -207 and -208.[13] All four could be radioactive since the hypothetical alpha decay of each would be exothermic, but the lower half-life has been established for lead-204 alone: more than 1.4 × 1017 years. [ ] However, this effect is so weak that natural lead does not pose a radiation hazard. Three isotopes are also found in three of the four main decay chains: lead-206, -207, and -208 are end products of uranium-238, uranium-235, and thorium-232, respectively. Since its amounts in nature also depend on the presence of other elements, the isotopic composition of natural lead varies depending on the sample: in particular, the relative amount of lead-206 varies between 20.84% and 27.78%.[ 13 ] In addition to the Thirty-four radioisotopes have been synthesized stable: they have mass numbers from 178-215. [ ] Lead-205 is the most stable radioisotope of lead with a half-life of over 107 years. 47 nuclear isomers (long lifetime

Lead

54 nuclear excited states corresponding to 24 lead isotopes have been characterized. The longest-lived isomer is lead-204m2 (half-life approximately 1.1 hours).[]

Chemical Reactivity Lead is classified as a post-transition metal and is also a member of the carbon group. Lead forms only a protective oxide layer, although finely powdered high purity lead can ignite in air. Molten lead oxidizes to lead monoxide in air. All chalcogens oxidize lead when heated.[14] Fluorine does not oxidize cold lead. Hot lead can be oxidized, but the formation of a protective halide layer reduces the intensity of the reaction above 100°C (210°F). The situation is similar with chlorine: thanks to the chloride layer, lead is more resistant to chlorine up to 300 °C than copper or steel.[14] Water in the presence of oxygen attack leads to starting an accelerating reaction. The presence of carbonates or sulfates leads to the formation of insoluble lead salts that protect the metal from corrosion. The same thing happens with carbon dioxide as insoluble lead carbonate is formed; however, excess gas leads to the formation of soluble bicarbonate; this makes the use of lead pipes dangerous.[11] Lead, thanks to complexation, dissolves in organic acids (in the presence of oxygen) and concentrated sulfuric acid (≥80%); however, it is only weakly attacked by hydrochloric acid and is stable to hydrofluoric acid, since the corresponding halides are poorly soluble. Due to the amphoteric character and the solubility of plumbites, lead also dissolves in very concentrated alkalis (≥10%).[11]

Compounds Lead compounds exist primarily in two main oxidation states, +2 and +4. The former is more common. Inorganic lead(IV) compounds are usually strong oxidizing agents or only exist in strongly acidic solutions.[10]

Oxides and sulfides Three oxides are known: lead(II) oxide or lead monoxide (PbO), lead troxide (Pb3O4) (sometimes called "lead") and lead dioxide (PbO2). The monoxide exists in two allotropes: α-PbO and β-PbO, both with layered structures and four-coordinate lead. The alpha polymorph is red in color and has a Pb-O distance of 230 pm; the beta polymorph is yellow in color and has a PbÀO distance of 221 and 249 pm (due to the asymmetry).[15] Both polymorphs can exist under standard conditions (beta with small impurities (10-5 relative) like Si, Ge, Mo, etc.). PbO reacts with acids to form salts and with alkali to form plumbites, [Pb(OH)3]− or [Pb(OH)4]2−.[16] The monoxide oxidizes in air to triple tetroxide, which decomposes back to PbO at 550°C (1020°F). Carbon dioxide can be produced, for example, by halogenating lead(II) salts. Regardless of the polymorph, it is brown-black in color. The alpha allotrope is rhombohedral and the beta allotrope is tetragonal.[16] Both allotropes are black-brown in color and always contain some water which cannot be removed as decomposition also occurs on heating (in the case of PbO and Pb3O4). Carbon dioxide is a strong oxidizing agent: it can oxidize hydrochloric and sulfuric acid. It does not react with alkaline solutions, but reacts with solid alkali to form hydroxyplumbates or with basic oxides to form plumbates.[16] The reaction of lead salts with hydrogen sulfide produces lead monosulfide. The solid has a simple cubic structure, similar to rock salt, which holds up to the melting point of 2037°F (1114°C). When heated in air, it oxidizes to sulfate and then monoxide.[17] Lead monosulfide is nearly insoluble in water, weak acids and the (NH4)2S/(NH4)2S2 solution is key to the separation of lead from analytical Group I through III ions, tin, arsenic and antimony. However, it dissolves in nitric and hydrochloric acid to form elemental sulfur and hydrogen sulfide, respectively.[17] When heated to high pressure with sulfur, it gives the disulfide. In the compound, the lead atoms are connected octahedrally to the sulfur atoms.[18] It is also a semiconductor.[19] A mixture of monooxide and monosulfide forms the metal when heated.[] 2 PbO + PbS → 3 Pb + SO2

Lead

Halides and Other Salts Heating lead carbonate with hydrogen fluoride produces hydrofluoride, which when molten decomposes to form difluoride. This white crystalline powder is more soluble than diiodide but less soluble than dibromide and dichloride.[20] Tetrafluoride, a yellow crystalline powder, is unstable. Other dihalides are obtained by heating lead(II) salts with halides of other metals; Lead dihalides precipitate to give white orthorhombic crystals (diiodide forms yellow hexagonal crystals). It could also be a 3 kg lead weight used in a diving weight obtained by direct reaction of its components to the temperature of the belt. exceed the melting points of dihalides. Its solubility increases with temperature; the addition of further halides initially reduces the solubility, but then increases as a result of complexation, with the maximum coordination number 6 being the ionic strength of the solution. [21] Tetrachloride is obtained by dissolving the dioxide in hydrochloric acid; it is kept under concentrated sulfuric acid to avoid exothermic decomposition. Tetrabromide may not exist, and tetraiodide definitely does not exist.[22] Diastatide was also prepared.[23] The metal is not attacked by sulfuric or hydrochloric acid. It dissolves in nitric acid with evolution of nitrous oxide gas and forms dissolved Pb(NO3)2.[20] It is a solid that is highly soluble in water; is therefore a key to obtaining the precipitates of halides, sulfates, chromates, carbonates and basic carbonated lead salts of Pb3(OH)2(CO3)2.[] |

Organols The most well-known compounds are the two simplest derivatives of lead: tetramethyl lead (TML) and tetraethyl lead (TEL). Homologues of it as well as hexaethyldiplom (HEDL) are less stable. Tetraalkyl derivatives contain lead(IV) where the Pb-C bonds are covalent. Therefore, they resemble typical organic compounds.[24] Lead readily forms an equimolar alloy with sodium metal, which reacts with alkyl halides to form organometallic lead compounds such as tetraethyllead.[25] The Pb-C bond energies in TML and TEL are only 167 and 145 kJ/mol; Therefore, the compounds decompose upon heating and the first signs of TEL composition are seen at 100°C (210°F). During pyrolysis, elemental lead and alkyl radicals are formed; their interaction causes HEDL synthesis.[24] TML and TEL also degrade under sunlight or ultraviolet light.[26] In the presence of chlorine, alkyls begin to be replaced by chlorides; R2PbCl2 in the presence of HCl (a by-product of the above reaction) leads to complete mineralization to yield PbCl2. The reaction with bromine follows the same principle.[26]

History Lead has been widely used for thousands of years because it is widely available, easily mined, and easy to process. It is very malleable and easy to smell. Metallic lead beads dating back to 6400 BC have been found. found. C. near Çatalhöyük, in present-day Turkey.[27] In the early Bronze Age, lead was used with antimony and arsenic.[28] World lead production peaked in Roman times[] and the growing Industrial Revolution

The largest pre-industrial producer of lead was the Roman economy, with an estimated annual production of 80,000 tons, usually obtained as a by-product of extensive silver smelting. [][][29] Roman mining.

Lead

56 Activities took place in Central Europe, Roman Britain, the Balkans, Greece, Asia Minor and Hispania, which alone accounted for 40% of world production. Lead installation in the Latin West may have continued beyond the time of Theodoric the Great into the Middle Ages.[30] Many Roman lead pigs (ingots) figured in Derbyshire's lead mining history and in the history of industry in other English centres. The Romans also used molten lead to attach iron pins that held together large blocks of limestone in certain monumental buildings.[31] In alchemy, lead was considered the oldest metal and associated with the planet Saturn. Consequently, alchemists used the symbol of Saturn (the sickle, ♄) to refer to lead.[32] Up until the 17th century, tin was often indistinguishable from lead: lead was called Plumbum nigrum (literally "black lead"), while tin was called Plumbum candidum (literally "bright lead").[33] Its legacy throughout history can also be seen in other languages: the word "olovo" means lead in Czech, but in Russian ("олово") means tin.[34] The lead symbol Pb is an abbreviation of its Latin name plumbum for soft metal; the English words "plumbing", "plumber", "plumb-bob" and "plumb-bob" are also derived from this Latin root.[35]

Ingots of lead from Roman Britain on display at the Wells and Mendip Museum

Lead mining in the upper Mississippi region of the United States in 1865

Lead production in the United States began in the late 16th century by Native Americans in southeastern Missouri's Lead District, commonly called the Lead Belt, is a lead-mining region in southeastern Missouri. Notable among Missouri's lead mining companies in the district were the Desloge family and the Desloge Consolidated Lead Company of Desloge, Missouri and Bonne Terre, engaged in lead trading, mining and smelting from 1823 in Potosí to 1929.

Occurrence Metallic lead occurs naturally but is rare. Lead is normally found in ores containing zinc, silver and (most commonly) copper and is mined along with these metals. The most important lead ore is galena (PbS), which contains 86.6% lead by weight. Other common varieties are cerussite (PbCO3) and anglesite (PbSO4).[] Lead- and zinc-bearing carbonate and clastic deposits. Source: USGS

Lead

Mineral Processing Most ores contain less than 10% lead, and ores with as little as 3% lead can be mined economically. The ores are crushed and concentrated by froth flotation, typically to 70% or more. Sulfide ores are roasted and yield mainly lead oxide and a mixture of sulfates and silicates of lead and other metals contained in the ore.[36] Lead oxide from the roasting process is reduced to metal in a coke blast furnace. [ ] In the process, further layers are dissolved and float on the metallic lead. These are slag (silicates with 1.5% lead), stone (sulfides with 15% lead) and food (iron and copper arsenides). These wastes contain concentrations of copper, zinc, cadmium and bismuth that can be economically recovered, as well as their unreduced lead content.[36] galena, lead ore

Metallic lead resulting from roasting and blast furnace processes still contains significant arsenic, antimony, bismuth, zinc, copper, silver and gold impurities. The melt is treated with air, steam and sulfur in a reverberating furnace, which oxidizes impurities other than silver, gold and bismuth. Oxidized contaminants are removed by the slag where they float to the top and are removed. [36][] Since lead ores contain significant concentrations of silver, the molten metal is also often contaminated with silver. Both metallic silver and gold are economically extracted and recovered by the Parkes process. [][36][] Unsilvered lead is liberated from bismuth by the Betterton-Kroll process, in which it is treated with metallic calcium and magnesium, which form a skimmable bismuth slag. [36][] Very pure lead can be obtained by electrolytic processing of molten lead by the Betts process. The process uses impure lead anodes and pure lead cathodes in a silica fluoride electrolyte.[36][]

Production and Recycling Production and consumption of lead is increasing worldwide. The total annual production is around 8 million tons; about half is made from recycled scrap. Since 2008, the most important production countries have been Australia, China, USA, Peru, Canada, Mexico, Sweden, Morocco, South Africa and North Korea. [] Australia, China and the United States account for more than half of primary production. .[] In 2010[37] 9.6 million tons of lead were mined, of which 4.1 million tons were from mining.[37] At current consumption rates, it is estimated that the supply of lead will be exhausted in 42 years.[38] Environmental analyst Lester Brown suggested that lead could be exhausted in 18 years, based on an extrapolation of 2% annual growth. According to the International Resource Panel report “Metal Stocks in Society”, the world per capita stock of lead in society is 8 kg. Much of this occurs in more developed countries (20 to 150 kg per capita) than in less developed countries (1 to 4 kg per capita).[39]

Lead

Applications Elemental Form Contrary to popular belief, wooden pencil leads were never made from graphite. The term comes from the Roman style, called penicillus, a small brush used for painting.[40] When the pencil originated as a wrapped graphite writing tool, the specific type of graphite used was called plumbago (literally lead act or lead model). Lead is used where its low melting point, ductility and high density are beneficial. Lead's low melting point makes it easy to fire, allowing small arms ammunition and buckshot to be fired with a minimum of technical equipment. It is also inexpensive and denser than other base metals.[43]

Lead bricks are commonly used as a radiation shield.

Due to its high density and resistance to corrosion, lead is used as keel ballast on sailing ships.[44] Its high density allows to neutralize the effect of the wind pitch on the sails, occupies a small volume and therefore offers the least resistance under water. For the same reason, it is used in diving weight belts to counteract the natural buoyancy of the diver and his gear.[45] It does not have the weight/volume ratio of many heavy metals, but its low cost increases its use in these and other applications. More than half of US lead production (at least 1.15 million tons in 2000) is used in automobiles, primarily as electrodes in lead-acid batteries, which are widely used as automotive batteries.[46] Cathode (reduction) PbO2 + 4 H+ + SO2− – 4 + 2e → PbSO + 2 HO 4 2 Anode (oxidation) Pb + SO2− –[47][48] 4 → PbSO + 2e 4

Roman lead water pipes with taps

Lead is used as an electrode in the electrolysis process. It is used in soldering for electronics, although some countries are phasing out this use to reduce the amount of environmentally hazardous waste, and in high-voltage power cables as a jacketing material to prevent water from diffusing into the insulation. Lead is one of three metals used in the Museum Materials Oddy Test, which helps detect organic acids, aldehydes and acid gases. It is also used as a radiation shield (e.g. in X-ray rooms).[49] Molten lead is used as a coolant (e.g. for lead-cooled fast reactors).[50] Lead is added to brass to reduce machine tool wear. In the form of strips or ribbons, lead is used to personalize tennis rackets. Tennis racquets of the past sometimes had lead added by the manufacturer to increase weight.[51] It is also used to form glass rods for stained glass or other multi-light windows. The practice has become

Lead

59 less often, not because of the danger, but for stylistic reasons. Lead or lead foil is used in some areas in the design of walls, floors and ceilings in recording studios as a sound deadening layer where mechanically generated and airborne noise levels are reduced or virtually eliminated.[52] [53] It is the traditional base metal for organ pipes, mixed with varying amounts of tin to control the pipe's tone.[54][55] Lead has many uses in the construction industry (for example, lead sheet is used as a structural metal in roofing materials, siding, flashing, gutters and gutter joints, and roof parapets). Detailed lead frames serve as decorative motifs for attaching lead sheeting. Lead is still commonly used in statues and sculptures. Lead is often used to balance a car's wheels; This use is being phased out in favor of other materials for environmental reasons. Because of its half-life of 22.20 years, the radioactive isotope 210Pb is used to date marine sediments with radiometric methods.[56][57][58]

Lead pipes in Roman baths

Compounds Lead compounds are used as a coloring element in ceramic glazes, especially red and yellow colors.[59] Lead is commonly used in polyvinyl chloride (PVC) plastic that encases electrical wires.[60][61] Lead is used in some candles to treat the wick to ensure a longer and more even burn. Because of the hazards, European and North American manufacturers use more expensive alternatives such as zinc.[62][63] Lead glass consists of 12 to 28% lead oxide. It changes the optical properties of the glass and reduces the transmission of radiation.[64] Some artists using oil-based paints continue to use white lead carbonate, citing its properties versus alternatives. Tetraethyl lead is used as an anti-knock additive for jet fuel in piston-powered aircraft. Lead-based semiconductors such as lead telluride, lead selenide, and lead antimonide find applications in photovoltaic cells (solar energy) and infrared detectors.[]

Multicolored lead enamel on an 8th-century AD Tang Dynasty Chinese Sancai pottery cup.

Lead, pure or alloyed with tin, or antimony is the traditional material for bullets and shot in firearms.

Perforated cast lead on the wall of a bridge in Venice to attach the hard metal connecting rod

Lead

Earlier uses Lead pigments were used in lead paints for white, yellow, orange and red. Most uses have been discontinued due to the dangers of lead poisoning. Effective April 22, 2010, US federal law requires contractors to undertake renovation, repair, and painting projects that disrupt more than 6 square feet of paint in homes, daycares, and schools built before 1978. They must be certified and trained for certain professions. Lead Pollution Prevention Practices. Lead chromate is still used industrially. Lead carbonate (white) is the traditional pigment for the primary medium for oil painting, but has been largely replaced by zinc and titanium oxide pigments. It was also quickly replaced in water-based painting media. White lead carbonate was used by the Japanese Geisha and in the West to whiten the face, which was harmful to health.[65][66][67] Lead was the main component of the alloy used in the compounding of pig iron. It was used for plumbing (hence the name) as well as preserving food and drink in ancient Rome. Until the early 1970s, lead was used to join cast iron water pipes and as a material for small diameter water pipes.[68] Tetraethyl lead was used in leaded fuels to reduce engine knock, but this practice has been phased out in many countries around the world to reduce toxic pollution that affects people and the environment.[69][70][][71] Lead was used to make slingshots. Lead was used in shotgun pellets in the United States until about 1992, when it was banned (for waterfowl hunting only) and replaced with non-toxic ammunition, mostly steel ammunition. In the Netherlands, the use of lead for hunting and sport shooting was banned in 1993, leading to a sharp drop in lead emissions, from 230 tons in 1990 to 47.5 tons in 1995, two years after the ban.[72] Lead was a component of paints used in children's toys and is now banned in the US and throughout Europe (ROHS Directive). Lead was used in body filler used in many custom builds in the 1940s and 1960s, hence the term lead slide. Lead is a superconductor with a transition temperature of 7.2 K, which is why IBM tried to make a lead alloy Josephson effect computer.[73] Lead was also used in pesticides prior to the 1950s when orchards were specifically treated against cod.[74] Sailors used a lead cylinder attached to a long line for the vital navigational task of determining water depth by periodically lifting the lead. An insertion of soft tallow at its base allowed determination of the seabed's composition, further aiding in localizing the position.[75]

Health Effects Lead is a highly toxic metal (whether inhaled or ingested) that attacks nearly every organ and system in the body. The primary target of lead poisoning is the nervous system, in both adults and children. Prolonged exposure in adults can result in decreased performance of some tests that measure nervous system function.[76] Prolonged exposure to lead or its salts (especially soluble salts or the strong oxidizer PbO2) can lead to kidney disease and abdominal cramps. It can also cause weakness in the fingers, wrists, or ankles. Exposure to lead also causes a slight increase in blood pressure, particularly in middle-aged and elderly people, and can cause anemia. Exposure to high levels of lead can cause severe brain and kidney damage and death in adults and children. In pregnant women, high levels of lead can cause miscarriage. Chronic exposure to high concentrations has been shown to reduce male fertility.[77] Lead also damages nerve connections (especially in young children) and causes blood and brain disorders. Lead poisoning usually results from eating lead-contaminated food or water; but can also occur after accidental ingestion of contaminated soil, dust, or lead-based paint.[78] It is rapidly absorbed into the bloodstream and is reported to have adverse effects on the central nervous system, cardiovascular system, kidneys, and immune system.[79] The lead component limit (1.0 μg/g) is a benchmark for drug testing and represents the maximum daily intake that a person should consume. But even at this low level, prolonged ingestion can be dangerous for humans.[80][81] Treatment for lead poisoning consists of dimercaprol and succimer.[82]

Lead

NFPA-704

"Fire Diamond" for lead pellets

Concern about lead's role in cognitive deficits in children has led to widespread reductions in its use (lead exposure has been associated with learning disabilities).[83] Most cases of elevated blood lead in adults are work-related.[84] Elevated blood levels are associated with delayed puberty in girls.[85] Lead has often been shown to permanently reduce children's cognitive abilities at extremely low levels of exposure.[86] During the 20th century, the use of lead in color pigments was drastically reduced due to the risk of lead poisoning, particularly in children.[87][88] The mid-1980s saw a significant shift in lead end-use patterns. Much of this change was a result of consumer compliance with EE springs. UU. of environmental regulations that have significantly reduced or eliminated the use of lead in non-battery products such as gasoline, paint, sweat and water systems. The use of lead is further restricted by the EU RoHS directive.[89] Lead can still be found in harmful amounts in earthenware,[90] vinyl[] (such as is used for pipe and electrical wire insulation), and Chinese brass. Older homes can still contain significant amounts of lead paint. [ ] White lead paint has been phased out in developed countries, but yellow lead chromate is still used. Old paint should not be removed by sanding as this creates respirable dust.[91] Lead salts used in ceramic glazes have occasionally caused lead poisoning when acidic beverages such as fruit juice have leached lead ions from the glaze.[92] It has been suggested that what is known as "Devonian colic" arose from the use of lead-lined presses to extract apple juice in cider making. Lead is considered to be particularly harmful to female fertility. Lead(II) acetate (also known as lead sugar) was used as a sweetener for wine in the Roman Empire, which some believe to be a plausible explanation for the insanity of many Roman emperors and chronic lead poisoning. destruction of the empire. slow decrease. (see Fall of the Roman Empire #Lead Poisoning) [93]

Biochemistry of intoxication In the human body, lead inhibits porphobilinogen synthase and ferrochelatase, preventing both the formation of porphobilinogen and the incorporation of iron into protoporphyrin IX, the final step in heme synthesis. This leads to ineffective heme synthesis and subsequent microcytic anemia.[94] At lower concentrations, it acts as a calcium analog and disrupts ion channels during nerve conduction. This is one of the mechanisms by which it interferes with perception. Acute lead poisoning is treated with edetate calcium disodium: the calcium chelate of the disodium salt of ethylenediaminetetraacetic acid (EDTA). This chelating agent has a greater affinity for lead than for calcium, so lead chelate is formed by exchange. This is then excreted in the urine, leaving the calcium harmless.[95] According to the Agency for Toxic Substances and Disease Registry, a small amount (1%) of ingested lead is stored in the bones and the remainder is excreted in urine and feces by an adult within a few weeks of exposure. However, only about 32% of lead is excreted by a child.[96] Exposure to lead and bleaching chemicals can occur through inhalation, ingestion, and skin contact. Most exposure is through ingestion or inhalation; Skin exposure is unlikely in the US because leaded gasoline is no longer used. Exposure to lead is a global concern as lead mining and smelting is common in many countries. Most countries phased out the use of leaded gasoline in 2007. [ ] Lead exposure is primarily through ingestion. Lead paint is the main source of lead exposure for children. As lead paint deteriorates, it flakes off, crumbles into dust, and enters the body through hand-to-mouth contact or through contaminated food, water, or alcohol.

Lead

62 The use of certain home remedies can also expose people to lead or lead compounds.[] Lead can be ingested through fruits and vegetables that are contaminated by high levels of lead in the soil in which they are grown. The soil is contaminated by the accumulation of lead particles in pipes. , lead paint and residual emissions from leaded gasoline used before the Environmental Protection Agency issued the regulation circa 1980.[97] Using lead for water pipes is problematic in areas with soft or (and) acidic water. Hard water forms insoluble deposits on pipes, while soft, acidic water dissolves lead pipes.[98] Inhalation is the second most important route of exposure, particularly for workers in lead-related occupations. Almost all inhaled lead is absorbed by the body, for ingested lead it is 20-70%; Children absorb more than adults.[] Dermal exposure can be significant for a limited group of people who work with organic lead compounds, but is of minor concern for the general population. The skin absorption rate is also low for inorganic lead.[]

References [1] [4] [5] [6] [7] [8]

Polyanskiy 1986, S.18. Polyanskiy 1986, S.14. Lead 2004, S.12-220. Lead 2004, S.4-13. Lead 2004, S.12-219. Lead 2004, S.12-35.

[9] Lide 2004, pp.12-37. [10] Polyanskiy 1986, pp. 14-15. [11] Polyanskiy 1986, p.20. [13] Polyanskiy 1986, p.16. [14] Polyanskiy 1986, p.19. [15] Polyanskiy 1986, p.21. [16] Polyanskiy 1986, p.22. [17] Polyanskiy 1986, p.28. [20] Polyanskiy 1986, p.32. [21] Polyanskiy 1986, p.33. [22] Polyanskiy 1986, p.34. [24] Polyanskiy 1986, p.43. [26] Polyanskiy 1986, p.44. [29] see 1170f. [33] Polyanskiy 1986, p.8. [36] Charles A. Sutherland, Edward F. Milner, Robert C. Kerby, Herbert Teindl, Albert Melin Hermann M. Bolt "Lead" in Ullmann's Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH, Weinheim. [37] “Mining production: 4,117,000 tons; Metal production: 9,604,000 tons; Metal Use: 9,569,000 tons” by (See also their definitions of terms (http://www.ilzsg.org/static/generaldef.aspx).) [ 46] Getting the Lead Out: Impacts of and Alternatives For Automotive Lead Uses (http ://www.ecocenter.org/sites/default/files/publications/docs/GettingLeadOut.pdf), a report by Environmental Defense, Ecology Center, Clean Car Campaign (July 2003) [56] http://www. nrresearchpress. com/doi/abs/ 10. 1139/f83-069 [80] Heavy-Metals-Testing-USP/ (http://www.caspharma.com/Heavy-Metals-Testing-USP/). Kaspharma. with. Accessed on 01/23/2012. [81] Pharmaceuticals - Britannica Online Encyclopedia (http://www.britannica.com/EBchecked/topic/455151/pharmaceutical). British. with. Accessed on 01/23/2012.

Lead

Bibliography • Lide, R.D., ed. (2004). CRC Manual of Chemistry and Physics (84th ed.). Boca Raton (FL): CRC Press. ISBN978-0-8493-0484-2. • Polyanskiy, N.G. (1986). Fillipova, N.A., ed. Analytical Chemistry of the Elements: Lead (in Russian). Science.

Further Reading • Keisch, B.; Feller, R.L.; Levine, AS; Edwards, R.R. (1967). "Dating and Authenticating Artwork Measuring Natural Alpha Emitters". Science 155 (3767): 1238-1242. Bib Code: 1967Sci...155.1238K (http://adsabs.harvard.edu/abs/1967Sci...155.1238K). doi: 10.1126/science.155.3767.1238 (http://dx.doi.org/10.1126/science.155.3767.1238). PMID 17847535 (http://www.ncbi.nlm.nih.gov/pubmed/17847535). • Keisch, B. (1968). "Dating Works of Art by Their Natural Radioactivity: Improvements and Applications". Science 160 (3826): 413-415. Bib Code: 1968Sci...160..413K (http://adsabs.harvard.edu/abs/1968Sci...160..413K). doi: 10.1126/science.160.3826.413 (http://dx.doi.org/10.1126/science.160.3826.413). PMID 17740234 (http://www.ncbi.nlm.nih.gov/pubmed/17740234). • Keisch, B. (1968). "Discrimination of Lead Radioactivity Measurements: New Tool for Authentication". Curator 11(1): 41-52. doi: 10.1111/j.2151-6952.1968.tb00884.x (http://dx.doi.org/10.1111/j.2151-6952.1968.tb00884.x). • Casas, Jose S.; Surdo, José, ed. (2006). Lead chemistry, analytical aspects. Environmental and Health Impacts (http://www.google.com/books?id=D9nYWCv_FE4C&printsec=frontcover). Elsevier. ISBN 0-444-52945-4.

Externe Links • Leader (http://www.dmoz.org/Science/Chemistry/Elements/Lead//) im Open Directory Project • Podcast „Chemistry in Its Element“ (http://www.rsc.org/chemistryworld/podcast /element.asp) (MP3) aus der World of Chemistry der Royal Society of Chemistry: Blei (http://www.rsc.org/images/CIIE_lead_48kbps_tcm18-126010.mp3) • Blei (http://www.periodicvideos .com/videos/082.htm) im Periodensystem der Videos (University of Nottingham) • Lead Freewheels (http://www.leadfreewheels.org/) • National Lead Free Wheel Weight Initiative| Abfallminimierung|Abfall|US EPA (http://www.epa.gov/waste/hazard/wastemin/nlfwwi.htm) • CDC – NIOSH Pocket Guide to Chemical Hazards: Lead (http://www.cdc.gov/ niosh/npg/npgd0368.html)

Zink

Zink Zink Zn 30

copper ← zinc → gallium ↑

Zn ↓ Cd Zinc in the periodic table Appearance silver-grey

General Properties Name, Symbol, Number

Zinko, Zn, 30

pronunciation

/ˈzɪŋk/ ZINGK

item category

Transition metal alternatively considered post-transition metal

group, period, block

12, 4, diam

standard atomic weight

65.38(2)

Zink

65 Electronic configuration

[Ar] 3d10 4s2 2, 8, 18, 2

discovery of history

Indian metallurgists (before 1000 BC)

first isolation

Andreas Sigismund Marggraf (1746)

Recognized as a unique metal by Rasaratna Samuccaya (800) Physical Properties Phase

fest

Density (near room temperature)

7,14 g·cm−3

Density of the liquid in m.p.

6,57 g·cm−3

fusion point

692,68 K, 419,53 °C, 787,15 °F

boiling point

1180K, 907°C, 1665°F

heat of fusion

7.32 kJ·mol−1

heat of vaporization

123.6 kJ·mol-1

molar heat capacity

25.470 J mol-1 K-1 vapor pressure

P (Pa)

10 100 1 thousand 10 thousand 100 thousand

in T (K) 610 670 750 852 990 1179 Atomic Properties Oxidation States

+2, +1, 0 (amphoteres Oxid)

electronegativity

1.65 (Pauling scale)

Ionization energies (more)

1st: 906.4 kJ mol-1 2nd: 1733.3 kJ mol-1 3rd: 3833 kJ mol-1

Atomic func

134 hours

covalent ray

122±16h

Radio Van der Waals

139 hours

Zink

66 Different crystal structure

hexagonal compact

magnetic request

diamagnetic

Electrical resistance

(20 °C) 59,0 nΩ·m

thermal conductivity

116W·m−1·K−1

thermal expansion

(25 °C) 30,2 µm·m−1·K−1

Speed of Sound (thin bar)

(r.) (laminado) 3850m·s-1

modulus of elasticity

108 GPa

Schneidmodul

43 GPa

Volumenmodul

70 GPa

poison ratio

0,25

Mohs hardness

2.5

Brinell hardness

412 MPa

CAS registration number

7440-66-6 More stable isotopes Main article: Zinc isotopes

You are so

THE

half-life

DM OF (MeV)

Zn 48.6 % > 2.3 x 10¹&sup8; e b+b+

1.096

1,3519

Sixty-five

1.1155

64 65

Zink

sin

Zink 27,9 %

66 67

Zink

4,1%

cinco 18,8%

68 69

Zink

69m

Zink

243.8 dia

DP-Ni

Cu-

Zn is stable with 36 neutrons.

Zn is stable with 37 neutrons.

Zn is stable with 38 neutrons.

sin

56 minutes

b−

0,906

sin

1:76 p.m

b−

0,906

0,998

0.6 % >1.3×1016 e β-β-

Ga-ga-ge

sin

2.4 minutes

b−

2.82

71m

sin

3.97 dia

b−

2.82

sin

46.5 hours

b−

0,458

Zn Zn

Zink

Ga-ga-ga

Zinc, also spelled commercially, is a metallic chemical element; It has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is somewhat chemically similar to magnesium in that its ion is of a similar size and its only common oxidation state is +2. Zinc is the twenty-fourth most abundant element in the earth's crust and has five stable isotopes. The most common zinc mineral is sphalerite (zinc compound), a zinc sulfide

Zink

67 minerals. The largest recoverable amounts are in Australia, Asia and the United States. Zinc production includes ore flotation, torrefaction and final extraction with electricity (electro-extraction). Brass, an alloy of copper and zinc, has been used since at least the 10th century BC. used. Metallic zinc was not produced on a large scale in India until the 12th century, while the metal was unknown in Europe until the late 16th century. Mines in Rajasthan have provided definitive evidence of zinc production dating back to the 6th century BC. dating back to 300 BC.[1] To date, the earliest evidence of pure zinc comes from Zawar, Rajasthan, dating back to the 9th century AD, when the distillation process was used to produce pure zinc.[2] Alchemists burned zinc in air to form what they called "philosopher's wool". or snow.” The element was probably named by the alchemist Paracelsus after the German word zinc. The German chemist Andreas Sigismund Marggraf is usually credited with discovering pure metallic zinc in 1746. The work of Luigi Galvani and Alessandro Volta discovered the electrochemical properties of zinc in 1800. Corrosion resistant galvanizing (hot dip galvanizing) is the main application for zinc. Other applications are found in batteries, small non-structural castings and alloys such as brass. A variety of zinc compounds are commonly used, such as zinc carbonate and zinc gluconate (as dietary supplements), zinc chloride (in deodorants), zinc pyrithione (anti-dandruff shampoos), zinc sulfide (in fluorescent paints), and zinc methyl or zinc. Zinc is an essential mineral of “outstanding biological and health importance. " over two billion people in the developing world and is associated with many diseases, susceptibility to infections, and diarrhea that contribute to the death of an estimated 800,000 children worldwide each year. Zinc excess intake can lead to ataxia, lethargy and copper deficiency.

Properties Physical Properties Zinc, also known as spelt in nonscientific contexts,[4] is a lustrous, blue-white diamagnetic metal,[] although the more common commercial grades of the metal have an opaque surface.[] It is slightly less dense. . . than iron and has a hexagonal crystal structure.[] The metal is hard and brittle at most temperatures, but becomes malleable between 100 and 150 °C.[][] Above 210 °C the metal again becomes malleable, brittle and can penetrate Beating pulverizes.[5] Zinc is a good conductor of electricity. [ ] For a metal, zinc has relatively low melting (419.5 °C, 787.1 °F) and boiling (907 °C) points. [ ] Its melting point is the lowest of all transition metals except mercury and cadmium. [ ] Many alloys contain zinc, including brass, an alloy of copper and zinc. Other metals that have long been known to form binary alloys with zinc include aluminum, antimony, bismuth, gold, iron, lead, mercury, silver, tin, magnesium, cobalt, nickel, tellurium, and sodium.[6] Although neither zinc nor zirconium are ferromagnetic, their alloy ZrZn[]2 shows ferromagnetism below 35 K.

Zink

Occurrence Zinc makes up about 75 ppm (0.0075%) of the earth's crust, making it the 24th most common element. The soil contains 5 to 770 ppm zinc with an average of 64 ppm. Seawater has only 30 ppb zinc and the atmosphere contains 0.1 to 4 µg/m3.[] The element is normally found in ores in association with other base metals such as copper and lead.[7] Zinc is a chalcophile, meaning the element has a low affinity for oxides, preferring to associate with sulfides. Chalcophiles formed as the crust solidified under the reducing conditions of Earth's early atmosphere. [] Sphalerite, a form of zinc sulfide, is the most commonly extracted zinciferous ore as its concentrate contains 60-62% zinc. [7]

Sphalerit (ZnS)

Other minerals from which zinc is derived include smithsonite (zinc carbonate), hemimorphite (zinc silicate), wurtzite (another zinc sulfide), and sometimes hydrozincite (basic zinc carbonate).[] With the exception of wurtzite, all of these other minerals form as a result of weathering processes in early times

Zinc sulphides.[] Globally identified zinc resources are approximately 1.9 billion tons.[] The largest deposits are in Australia, Canada and the United States, with the largest reserves in Iran.[][8][9] On the face at the current rate of consumption, it is estimated that these reserves will be depleted sometime between 2027 and 2055.[10][11] About 346 million tons were mined throughout history up to 2002, and one estimate indicated that about 109 million tons are still in use.[12]

Isotopes Five isotopes of zinc occur naturally. 64Zn is the most abundant isotope (48.63% natural occurrence).[] This isotope has such a long half-life of 4.3 × 1018a[13] that its radioactivity can be neglected.[] Likewise, 70 Zn (0 .6%) with a half-life of 1.3 × 1016a, is not generally considered to be radioactive. The other naturally occurring isotopes are 66 Zn (28%), 67 Zn (4%) and 68 Zn (19%). Several dozen radioisotopes have been characterized. 65 Zn is the longest-lived radioisotope with a half-life of 243.66 days, followed by 72 Zn with a half-life of 46.5 hours.[] Zinc has 10 nuclear isomers. 69mZn has the longest half-life at 13.76 h.[] The superscript m indicates a metastable isotope. The nucleus of a metastable isotope is in an excited state and returns to the ground state by emitting a photon in the form of a gamma ray. 61 Zn has three excited states and 73 Zn has two.[14] The isotopes 65 Zn, 71 Zn, 77 Zn, and 78 Zn each have a single excited state.[] The most common decay mode of a zinc radioisotope with a mass number less than 66 is electron capture. The decay product resulting from electron capture is a copper isotope.[] n 30Zn + e− → n 29Cu

Zink

69 The most common mode of decay of a radioisotope of zinc with a mass number greater than 66 is beta decay (β–), which produces an isotope of gallium.[] n 30Zn → n 31Ga + e− + ν e

Compounds and Chemical Reactivity Zinc has an electronic configuration of [Ar]3d104s2 and is a member of Group 12 of the Periodic Table. It is a moderately reactive metal and a strong reducing agent. [] The bare metal surface quickly darkens and eventually forms a passive protective layer of basic zinc carbonate, Zn 5 (OH) 6 (CO ) 3 [15] 2 , upon reaction with atmospheric carbon dioxide. This layer helps prevent further reactions with air and water. Zinc burns in air with a bright blue-green flame and emits zinc oxide fumes.[] Zinc reacts readily with acids, bases, and other nonmetals.[16] High purity zinc reacts slowly with acids at room temperature. [ ] Strong acids such as hydrochloric or sulfuric acid can remove the passivation layer and subsequent reaction with water releases hydrogen gas. [ ] Zinc chemistry is dominated by the +2 oxidation state. When compounds are formed in this oxidation state, electrons are lost from the outer shell, yielding a naked zinc ion with the electronic configuration [Ar]3d10.[17] In aqueous solution, an octahedral complex, [Zn(H 2O) ]2+ 6 , is the predominant species.[18] The volatilization of zinc in conjunction with zinc chloride at temperatures above 285°C indicates the formation of Zn 2Cl [] 2 , a zinc compound with the +1 oxidation state. Zinc compounds in oxidation states other than +1 or +2 are not known.[19] Calculations show that it is unlikely that a zinc compound with the +4 oxidation state exists.[20] Zinc's chemistry is similar to the chemistry of the later first-stage transition metals, nickel and copper, although it has a filled D-layer, so its compounds are diamagnetic and mostly colorless. [ ] The ionic radii of zinc and magnesium are almost identical. Therefore, some of their salts have the same crystal structure [21] and in circumstances where ionic radius is a determining factor, the chemistries of zinc and magnesium have much in common. [ ] Otherwise there is little resemblance. Zinc tends to form bonds with a higher degree of covalency and forms much more stable complexes with N- and S-donors.[ ] Zinc complexes are mostly 4- or 6-coordinate, although 5-coordinate complexes are known. [] See also Clemmensen's reduction.

Zinc(I) Compounds Zinc(I) compounds are rare and require bulky binders to stabilize the low oxidation state. Most zinc(I) compounds formally contain the [Zn2]2+ nucleus, which is analogous to the dimeric [Hg2]2+ cation present in mercury(I) compounds. The diamagnetic nature of the ion confirms its dimeric structure. The first zinc(I) compound with a ZnАZn bond, (η5-C5Me5)2Zn2, is also the first dimetallocene. The [Zn2]2+ ion rapidly disproportionates into zinc metal and zinc(II) and has only been obtained as a yellow glass formed by cooling a solution of zinc metal in molten ZnCl2.[22]

Zink

zinc(II) compounds

Zinc Acetate

Zinkchlorid

Binary zinc compounds are known for most semimetals and all nonmetals except the noble gases. ZnO oxide is a white powder that is almost insoluble in neutral aqueous solutions, but it is amphoteric and soluble in both strongly acidic and basic solutions.[] The other chalcogenides (ZnS, ZnSe, and ZnTe) have different applications in electronics and optics. [23] Pnictogenides (Zn 3N 2, Zn 3P 2, Zn 3As 2, and Zn 3Sb [24][25] 2), peroxide (ZnO 2), hydride (ZnH 2), and carbide (ZnC [26] 2) are also available available known. Of the four halides, ZnF 2 has the strongest ionic character, while the others (ZnCl

ZnBr and ZnI[] 2) have relatively low melting points and are considered to be more covalent. two,

In weakly basic solutions containing Zn2+ ions, Zn(OH)2 hydroxide forms as a white precipitate. In more alkaline solutions, this hydroxide dissolves to form zincates ([Zn(OH)4]2− ).[] Zn(NO3) 2 nitrate, Zn(ClO) 3 chlorate 2, ZnSO 4 sulfate, Zn 3 phosphate (PO ) 4 2, ZnMoO 4 molybdate, Zn(CN) 2 cyanide, Zn(AsO ) 2 2 arsenite, Zn(AsO ) 4 2 8H 2O arsenate, and ZnCrO [27][] 4 chromate (one of the few zinc compounds) are some examples for other common inorganic zinc compounds. One of the simplest examples of an organic zinc compound is acetate (Zn(O 2CCH ) 3 2). Organozinc compounds are those containing zinc-carbon covalent bonds. Diethylzinc ((C 2H) 5 2Zn) is a reagent in synthetic chemistry. It was first described in 1848 from the reaction of zinc and ethyl iodide and was the first known compound to contain a metal–carbon sigma bond.[28]

Zink

History Ancient Uses Several isolated examples of the ancient use of impure zinc have been discovered. Zinc ores were used as a separate element to make copper-zinc alloy brass many centuries before the discovery of zinc. Judean brass from the 14th to 10th centuries BC. C. contains 23% zinc.[] Knowledge of the production of brass spread in the 7th century BC. in ancient Greece. C., but only a few varieties have been produced.[29] Ornaments made from alloys containing 80-90% zinc and lead, with iron, antimony and other metals making up the remainder, have been found to be 2,500 years old. [7] A possibly prehistoric figure containing 87.5% zinc was found at an archaeological site in Dacia. [ ] The Romans knew about the year 30 BC. from the manufacture of brass. together in a crucible. [ ] The resulting calamine brass was shaped or hammered into shape and used in weapons. [30] Some coins minted by the Romans in the Christian era are probably made of calamine brass.[]

Late Roman brass bucket: the Hemmoor bucket from Warstade, Germany, 2nd-3rd cent. century AD

Strabo, in a passage belonging to an earlier writer of the 4th century B.C. is taken. C., Wikipedia: Avoid Weasel Words mentions "drops of fake silver" which when mixed with copper make brass. This may refer to small amounts of zinc as a by-product of smelting sulfide ore.[31] Zinc in such scraps in smelting furnaces was usually discarded as it was considered useless. [] The Bern zinc tablet is a votive tablet from Roman Gaul made of an alloy consisting mainly of zinc. [32] The Charaka Samhita, believed to be around 500 B.C. was written. C. or earlier, Wikipedia: The disputed statement mentions a metal that when oxidized produces pushpanjan, believed to be zinc oxide.[33] Zinc mines at Zawar, near Udaipur, India have been active since the Maurya period. However, the smelting of metallic zinc seems to have started here around the 12th century AD.[34][32] According to one estimate, this site produced one million tons of zinc metal and zinc oxide between the 12th and 16th centuries.[] Another estimate gives a total production of 60,000 tons of zinc metal during this period.[34] The Rasaratna Samuccaya, written around the 13th century AD C., names two types of minerals containing zinc; one for metal extraction and the other for medicinal use.[32]

Early Studies and Names Zinc was clearly recognized as a metal under the designation Yasada or Jasada in the medical lexicon attributed to the Hindu king Madanapala and written around 1374.[35] The smelting and extraction of impure zinc by reducing calamine with wool and other organic matter was practiced in India in the 13th century.[][] The Chinese only learned the technique in the 17th century.[]

Various alchemical symbols attributed to the element zinc.

Alchemists burned metallic zinc in air and collected the resulting zinc oxide in a condenser. Some alchemists called this zinc oxide lana philosophica, Latin for "philosopher's wool" because it accumulated in tufts of wool, while others thought it looked like white snow and called it nix album.[36] The metal's name was probably first documented by Paracelsus, a Swiss-born German alchemist, who referred to the metal as "zinc".

or "tine" in his book Liber Mineralium II in the 16th century. a needle

Zink

72 appearance).[38] Zinc can also mean "like tin" due to its relationship to the German zinn, which means tin.[39] Another possibility is that the word derives from the Persian word ﺳﻨﮓseng, meaning stone.[40] The metal has also been called Indian tin, tutanego, calamine, and spinneret.[7] The German metallurgist Andreas Libavius received a quantity of what he called the Malabar "Calay" from a freighter captured by the Portuguese in 1596.[41] Libavius described the properties of the sample, which may have been zinc. Zinc was regularly imported into Europe from the East in the 17th and early 18th centuries[] but it was sometimes very expensive.[42]

Insulation Metallic zinc insulation in the West may have been done independently by several people. Postlewayt's Universal Dictionary, a contemporary source providing information on technology in Europe, did not mention zinc until 1751, but the element was studied before that.[32][43] The Flemish metallurgist P.M. de Respour reported that he extracted metallic zinc from zinc oxide in 1668. [] In the early 18th century, Étienne François Geoffroy described zinc oxide condensing as yellow crystals on iron rods placed on a zinc ore smelter. [] In Britain, John Lane is said to have carried out zinc smelting experiments, probably in Landore, before his bankruptcy in 1726.[44] In 1738, William Champion in Great Britain patented a process for extracting zinc from calamine in a vertical retort casting.[45] Its technology was similar to that at the Zawar zinc mines in Rajasthan, but there is no evidence that it ever visited the East.[46] The Champion process was used until 1851.[]

Andreas Sigismund Marggraf is credited with the first insulating pure zinc

The German chemist Andreas Marggraf is usually credited with discovering pure metallic zinc, although the Swedish chemist Anton von Swab distilled zinc from calamine four years earlier. [] In his 1746 experiment, Marggraf heated a mixture of calamine and charcoal in a closed vessel without copper to obtain a metal. [ ] This process became commercially viable in 1752. [47]

work later

Electroplating is named after Luigi Galvani.

In 1758, William Champion's brother, John, patented a process for calcining zinc sulfide to an oxide usable in the retort process.[7] Before that, only calamine could be used to make zinc. In 1798, Johann Christian Ruberg improved the casting process by building the first horizontal retort foundry.[48] Jean-Jacques Daniel Dony built another type of horizontal zinc smelter in Belgium that processed even more zinc. [] Italian physician Luigi Galvani discovered in 1780 that attaching the spinal cord of a freshly dissected frog to an iron splint held by a brass hook caused the frog's leg to tremble. [ ] He mistakenly believed to have discovered an ability of nerves and muscles to generate electricity and called the effect "animal electricity". [] The galvanic cell and plating process were named after Luigi Galvani, and these discoveries paved the way for electric batteries, plating, and cathodic protection.[]

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73 Galvani's friend Alessandro Volta studied this effect further and invented the voltaic battery in 1800.[] The basic unit of Volta's battery was a simplified galvanic cell consisting of a copper plate and a zinc plate bonded together. external and separated by an electrolyte. These were stacked in series to make the voltaic cell, which in turn produced electricity by conducting electrons from the zinc to the copper, causing the zinc to corrode. [] The non-magnetic character of zinc and its colorlessness in solution delayed its discovery. its importance in biochemistry and nutrition.[] This changed in the 1940s when it was shown that carbonic anhydrase, an enzyme that removes carbon dioxide from the blood, contained zinc in its active site.[] The digestive enzyme carboxypeptidase became the second known Substance containing zinc. enzyme in 1955.[]

Production Mining and Processing Major Zinc Producing Countries 2010[] Ranking

Land

Staple

porcelain

3.500.000

Peru

1.520.000

Australia

1.450.000

750.000

United States of America

720.000

You have

670.000

Zinc is the fourth most used metal after iron, aluminum and copper with an annual production of around 12 million tonnes.[] The world's largest producer of zinc is Nyrstar, a merger of Australia's OZ Minerals and Australia's OZ Minerals. from the Belgian Umicore. [49] Approximately 70% of the world's zinc comes from mining, while the remaining [] 30% comes from recycling. Percentage of zinc production in 2006 by country [50] secondary zinc. Commercially pure zinc is known as Special High Grade, often abbreviated SHG, and is 99.995% pure.[51] Globally, 95% of zinc is mined from sulphide ore deposits where ZnS sphalerite is almost always mixed with copper, lead and iron sulphides.[] Zinc is mined worldwide and the main mining areas are China, Australia and Peru. China produced 29% of global zinc production in 2010. [] Metallic zinc is produced by extractive metallurgy. its hydrophobicity to obtain a mineral concentrate. [] This process results in a final zinc concentration of approximately 50%, with the remainder of the concentrate being sulfur (32%), iron (13%) and SiO 2 (5%). Roasting converts the zinc sulfide concentrate produced during processing into zinc oxide:[]

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74 2 ZnS + 3 O 2 → 2 ZnO + 2 SO 2

Sulfur dioxide is used to produce sulfuric acid, which is needed for the leaching process. If zinc carbonate, zinc silicate or zinc spinel deposits such as the Skorpion deposit in Namibia are used for zinc extraction, roasting can be dispensed with. [] Two basic methods are used for further processing: pyrometallurgy or electrowinning. Pyrometallurgical processing reduces zinc oxide with carbon or carbon monoxide at 950 °C (1740 °F) in the metal, which is distilled as zinc vapor. Zinc vapor is collected in a condenser.[] The following set of equations demonstrates this process:[] 2 ZnO + C → 2 Zn + CO 2

ZnO + CO → Zn + CO2

The electrolytic extraction process dissolves zinc from the ore concentrate by sulfuric acid:[53] ZnO + H 2SO 4 → ZnSO 4+ H 2O After this step, electrolysis is used to produce metallic zinc[] 2 ZnSO 4+ 2 H 2O → 2Zn + 2H2SO4+ O2

The regenerated sulfuric acid is returned to the leaching stage.

Impact on the environment The production of zinc sulphide ores generates large amounts of sulfur dioxide and cadmium fumes. Foundry slag and other process residues also contain significant amounts of heavy metals. Between 1806 and 1882, approximately 1.1 million tons of metallic zinc and 130,000 tons of lead were mined in the Belgian towns of La Calamine and Plombières, and when smelted, the Geul river sediments contain significant amounts of heavy metals. [] About 2,000 years ago, zinc emissions from mining and smelting were 10,000 tons per year. After a tenfold increase since 1850, zinc emissions peaked at 3.4 million tons per year in the 1980s and fell to 2.7 million tons in the 1990s, although a 2005 study of the Arctic troposphere found that the concentrations did not reflect the decline. Anthropogenic and natural emissions occur in a 20 to 1 ratio.[] Zinc levels in rivers flowing through industrial or mining areas can be as high as 20 ppm.[] Effective wastewater treatment reduces this level significantly; For example, treatment along the Rhine reduced zinc levels to 50 ppb. [ ] Zinc levels as low as 2 ppm negatively affect the amount of oxygen that fish can carry in their blood. [54]

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Historically responsible for high concentrations of heavy metals in the Derwent River,[55] the Lutana Zinc Works is Tasmania's largest exporter, generating 2.5% of the state's GDP and producing over 250,000 tonnes of zinc annually.[56] Soils contaminated with zinc from mining of zinciferous ores, refining, or use of zinciferous sludge as fertilizer can contain several grams of zinc per kilogram of dry soil. Zinc levels above 500 ppm in soil impair the ability of plants to take up other essential metals such as iron and manganese. Zinc levels from 2,000 ppm to 180,000 ppm (18%) were found in some soil samples.[]

Applications Major applications of zinc include (numbers are for US)[] 1st 2nd 3rd 4th

Electroplating (55%) Alloys (21%) Brass and Bronze (16%) Other (8%)

Corrosion Prevention and Batteries Metal is most commonly used as a corrosion inhibitor. [ ] Galvanizing, which is the coating of iron or steel to protect metals from corrosion, is the most well-known way of using zinc in this way. In 2009, 55% or 893,000 tons of metallic zinc was used for galvanizing in the United States. of oxide and carbonate (Zn 5(OH) Crystalline surface of hot-dip galvanized handrail 6(CO 3)[] 2) forms as the zinc corrodes. This protection continues even after the zinc layer has been scratched, but will deteriorate over time as the zinc corrodes.[] Zinc is applied electrochemically or as molten zinc by hot dip galvanizing or spraying. Electroplating is used on wire fences, railings, suspension bridges, poles, metal roofs, heat exchangers, and auto bodies. [] The relative reactivity of zinc and its ability to attract oxidation make it an efficient sacrificial anode in cathodic processes. Protection (PC). For example, cathodic protection of a buried pipe can be achieved by bonding anodes of zinc to the pipe.[] The zinc acts as an anode (negative terminal) and slowly corrodes when an electric current is passed through the steel pipe.[ ][57] Zinc becomes also used to cathodically protect metals exposed to seawater from corrosion.[58] A zinc disk attached to a ship's iron rudder will slowly corrode as long as the rudder remains intact. With a standard electrode potential (SEP) of -0.76 volts, zinc is used as an anode material for batteries. (More reactive lithium (SEP -3.04 V) is used for the anodes in lithium batteries.) Powdered zinc is used in this way in alkaline batteries, and zinc sheets form the cases and act as anodes in zinc-zinc batteries. 59][60] Zinc is used as an anode or fuel in the zinc-air battery/fuel cell.[61][62][63]

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Alloys A widespread alloy containing zinc is brass, in which copper is alloyed with 3% to 45% zinc, depending on the type of brass. [ ] Brass is generally more ductile and stronger than copper and has superior corrosion resistance. [ ] These properties make it useful in communications devices, hardware, musical instruments, and water valves.[ ]

Cast brass microstructure at 400x magnification

Other widely used zinc-containing alloys include German silver, typewriter metal, solder, and commercial aluminum and bronze. [ ] Zinc is also used in modern pipe organs as a replacement for the traditional alloy of lead and tin in pipes. Alloys of 85 to 88% zinc, 4 to 10% copper and 2 to 8% aluminum have limited use in certain types of machine bearings. Zinc has been the primary metal used in the manufacture of US pennies since 1982. [ ] The zinc core is covered with a thin layer of copper to give the appearance of a copper coin. In 1994, 33,200 tons (36,600 short tons) of zinc were used to produce 13.6 billion US cents.[]

Zinc alloys, mainly with small amounts of copper, aluminum, and magnesium, are useful in die and centrifugal casting, particularly in the automotive, electrical, and hardware industries.[65] These alloys are marketed under the name Zamak.[65] An example of this is aluminum zinc. The low melting point together with the low viscosity of the alloy enables the production of small and intricate shapes. The low working temperature leads to a rapid cooling of the cast products and thus a quick assembly is possible. like steel but as malleable as plastic.[][67] This superplasticity of the alloy allows it to be cast in ceramic and cement forms.[] Similar alloys with the addition of a small amount of lead can be cold rolled. in leaves. An alloy of 96% zinc and 4% aluminum is used to make stamping tools for low production applications where ferrous metal tools would be too expensive.[36] Alloys of zinc with titanium and copper are used in the construction of facades, roofs or other applications where zinc is used as sheet metal and for processes such as deep drawing, profiling or bending. [ ] Unalloyed zinc is too fragile for this type of production. Legal action. [ ] A dense, inexpensive, and easy-to-work material, zinc is used as a substitute for lead. After lead problems, zinc is popping up in weights for a variety of applications from fishing[68] to tire scales and steering wheels.[] Zinc cadmium telluride (CZT) is a semiconductor alloy that can be broken down into several small sensor devices. [ ] These devices resemble an integrated circuit and can detect the energy of incident gamma-ray photons. [ ] Placed behind an absorbing mask, the CZT sensor array can also be used to determine the direction of the beam. []

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Other Industrial Uses Approximately one quarter of all zinc production in the United States (2009) is consumed in the form of zinc compounds; [ ] many of which are used industrially. Zinc oxide is widely used as a white pigment in paints and as a catalyst in rubber manufacture. It is also used as a heat sink for rubber and protects its polymers from ultraviolet radiation (the same UV protection is given to plastics containing zinc oxide). Zinc oxide's semiconducting properties make it useful for varistors and photocopying products. [69] The zinc-zinc oxide cycle is a two-step thermochemical process based on zinc and zinc oxide to produce hydrogen.[70] Zinc oxide is used as a white pigment in paints.

Zinc chloride is often added to wood as a flame retardant[] and can be used as a wood preservative.[71] It is also used to make other chemicals. [] Zinc methyl (Zn(CH3)[72]2) is used in various organic syntheses. Zinc sulfide (ZnS) is used in luminescent pigments such as clock hands, X-ray and television screens, and luminescent paints.[] ZnS crystals are used in lasers that operate in the mid-infrared region of the spectrum. [73] Zinc sulfate is a chemical in dyes and pigments.[] Zinc pyrithione is used in antifouling paints.[74] Zinc dust is sometimes used as a propellant in model rockets. Gas. , heat, and light.[] Zinc sheet is used to make zinc ingots.[75] 64

Zn, the most abundant isotope of zinc, is highly susceptible to neutron activation as it is converted to the highly radioactive 65 Zn, which has a half-life of 244 days and produces intense gamma radiation. For this reason, zinc oxide, which is used in nuclear reactors as a corrosion inhibitor, is depleted to 64 Zn before use, this is known as depleted zinc oxide. Zinc has been proposed as a salt material for nuclear weapons for the same reason (cobalt is another well-known salt material). explosive thermonuclear weapon that forms a large amount of 65 Zn and significantly increases the radioactivity of the weapon fallout. [ ] None of these weapons were ever built, tested or used. Investigate how zinc-containing alloys wear out, or the pathway and role of zinc in organisms.[76] Zinc dithiocarbamate complexes are used as agricultural fungicides; these include zineb, metiram, propineb, and ziram.[77] Zinc naphthenate is used as a wood preservative.[78] Zinc is also used in the form of ZDDP as an anti-wear additive for metal parts in engine oil.[79]

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Dietary Supplements Zinc is found in individual tablets in most over-the-counter daily vitamin and mineral supplements. [ ] Preparations include zinc oxide, zinc acetate, and zinc gluconate. [ ] It is believed to have antioxidant properties that may protect against accelerated aging. the skin and muscles of the body; Studies differ on its effectiveness.[] Zinc also helps speed the healing process after an injury.[] It is also thought to be beneficial for the body's immune system. In fact, zinc deficiency can affect virtually every part of the human immune system.[80] The effectiveness of zinc compounds in reducing the duration or severity of cold symptoms is controversial.[81] A 2011 systematic review concludes that supplementation results in a modest reduction in the duration and severity of cold symptoms.[82] The optimal dosage and formulation has not been determined. Studies included in the 2011 review used a variety of forms and dosages of zinc, including zinc gluconate or zinc acetate lozenges and zinc sulfate syrup. Doses ranged from 30 to 160 milligrams per day. The researchers reported the following: Given the variability in the studied populations (there are no studies from low- and middle-income countries), dose, formulation and duration, GNC Zinc Zinc 50 mg (AU) tablets were used used in the included studies. More research is needed to account for these variables and to determine the optimal duration of treatment, dose, and zinc formulations that provide clinical benefit without increasing side effects before making a general recommendation for zinc treatment. Zinc serves as a simple, inexpensive, and essential treatment for diarrheal diseases in children in developing countries. Zinc is used up in the body during diarrhea, but recent studies suggest that zinc replacement with a 10- to 14-day treatment cycle can reduce the duration and severity of diarrheal episodes and also prevent future episodes for up to three months.[83]

Zinc gluconate is a compound used to deliver zinc as a dietary supplement.

The Age-Related Eye Disease Study found that zinc could be part of an effective treatment for age-related macular degeneration.[84] Zinc supplementation is an effective treatment for acrodermatitis enteropathica, a genetic condition that affects zinc absorption and was previously fatal to babies born with it.[]

Gastroenteritis is greatly attenuated by zinc intake, and this effect may be due to the direct antimicrobial action of zinc ions in the gastrointestinal tract or the uptake and release of zinc by immune cells (zinc is secreted by all granulocytes). , or both.[85][86][87] In 2011, researchers at the John Jay College of Criminal Justice reported that zinc supplements can mask the presence of drugs in urine. Similar claims have been made on the subject on web forums.[88] Although it has not yet been tested as a therapy in humans, a growing body of evidence suggests that zinc preferentially kills prostate cancer cells. Because zinc is naturally housed in the prostate and the prostate is accessible by relatively noninvasive procedures, its potential as a chemotherapeutic agent in this type of cancer has shown promise.[89] However, other studies have shown that chronic use of zinc supplements in excess of the recommended dose may actually increase the likelihood of developing prostate cancer, probably also due to the natural accumulation of this heavy metal in the prostate.[90]

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Topical Application Topical administration of zinc preparations includes those used on the skin, often in the form of zinc oxide. Zinc supplements can protect against sunburn in summer and windburn in winter. Toothpaste to prevent bad breath.[91] Zinc pyrithione is often used in shampoos because of its antidandruff function.[92] Zinc ions are effective antimicrobial agents even at low concentrations.[93]

Organic Chemistry There are many important organic zinc compounds. Organozinc chemistry is the science of organozinc compounds that describes their physical properties, synthesis, and reactions.[94][95][96][97] Important applications are the Frankland-Duppa reaction, in which an oxalate ester (ROCOCOOR) reacts with an alkyl halide R'X, zinc and hydrochloric acid to form RR'COHCOOR-α-hydroxycarboxylic acid esters, [98] the Reformatskii reaction for the conversion of α-halo esters and aldehydes to β-hydroxyesters, addition of diphenylzinc to an aldehyde Simmons-Smith reaction in which zinc iodide (iodomethyl)carbenoid reacts with alkene (or alkyne) and converts them to cyclopropane, addition reaction of organozinc compounds to carbonyl compounds. The Barbier reaction (1899), which is the zinc equivalent of the magnesium Grignard reaction and is the better of the two. In the presence of almost any water, organomagnesium halide formation fails, while the Barbier reaction can take place even in water. On the other hand, organozincs are much less nucleophilic than Grignard, expensive, and difficult to handle. Commercially available diorganozinc compounds are dimethylzinc, diethylzinc and diphenylzinc. In one study [99][100] the active organic zinc compound is obtained from much cheaper organobromine precursors: the Negishi coupling is also an important reaction for the formation of new carbon–carbon bonds between unsaturated carbon atoms in alkenes, arenes, and alkynes. The catalysts are nickel and palladium. A key step in the catalytic cycle is a transmetalation, in which a zinc halide exchanges its organic substituent for another halogen containing a palladium (nickel) metal center. The Fukuyama coupling is another coupling reaction, but this one with a thioester reactant that forms a ketone.

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Biological role Zinc is an essential trace element necessary for plants,[] animals[101] and microorganisms[102]. Zinc is found in almost 100 specific enzymes[] (other sources speak of 300), serves as structural ions in transcription factors, and is stored and transferred in metallothioneins. [ ] It is "typically the second most abundant transition metal in organisms" after iron and the only metal found in all classes of enzymes. [ ] In proteins, Zn ions normally coordinate to the amino acid side chains of aspartic acid, glutamic acid, cysteine, and histidine. The theoretical and computational description of this binding of zinc in proteins (like that of other transition metals) is difficult.[103] 2-4 grams [zinc] are distributed in the human body. Most zinc is found in the brain, muscle, bone, kidney and liver, with the highest concentrations in the prostate and parts of the eye.[104] Sperm is particularly rich in zinc, which is a key factor in prostate function and reproductive organ growth. [ ] In humans, zinc performs "ubiquitous biological functions." organic ligands",[] and has functions in RNA and DNA metabolism, signaling, and gene expression. It also regulates apoptosis. A 2006 study estimated that about 10% of human proteins (2,800) potentially contain zinc bind, in addition to the hundreds that transport it and traffic zinc; a similar in silico study in the plant Arabidopsis thaliana found 2,367 zinc-related proteins.[] In the brain, zinc is stored via glutamatergic neurons in specific synaptic vesicles[] and can affect the Brain excitability "modulates" the normal functioning of the brain and central nervous system.[]

Enzymes Zinc is an efficient Lewis acid, making it a useful catalyst in hydroxylations and other enzymatic reactions.[] The metal also has a flexible coordination geometry that allows proteins that use it to rapidly change conformation to carry out reactions. [106] Two examples of the zinc-containing enzymes are carbonic anhydrase and carboxypeptidase, which are crucial for the regulation of carbon dioxide (CO [] 2 ) and protein digestion, respectively. In vertebrate blood, carbonic anhydrase converts CO 2 to bicarbonate, and the same enzyme converts the bicarbonate strand diagram of human carbonic anhydrase II back to CO [107] with a zinc atom visible in center 2 for exhalation from the lungs. Without this enzyme, this [ ] conversion would occur approximately a million times slower at a normal blood pH of 7, or would require a pH of 10 or higher. [ ] The unrelated β-carbonic anhydrase is required in plants for leaf formation, the synthesis of indoleacetic acid (auxin), and alcoholic fermentation.[108] Carboxypeptidase cleaves peptide bonds during protein digestion. A coordinated covalent bond is formed between the terminal peptide and a C=O group attached to the zinc, conferring a positive charge on the carbon. This helps create a hydrophobic pocket in the enzyme near the zinc that attracts the non-polar portion of the protein being digested.[]

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other proteins

Zinc fingers help read DNA sequences.

Zinc plays a purely structural role in zinc fingers, loops, and clusters.[] Zinc fingers are part of some transcription factors, which are proteins that recognize DNA base sequences during DNA replication and transcription. Each of the nine or ten Zn2+ ions in a zinc finger helps maintain the structure of the finger by coordinating to four amino acids in the transcription factor DNA sequence.

In the blood plasma, zinc is bound and transported to albumin (60%, low affinity) and transferrin (10%)[] since transferrin also transports iron, excess iron reduces zinc absorption and vice versa. A similar reaction occurs with copper.[] The concentration of zinc in the blood plasma remains relatively constant regardless of zinc intake.[] Signaling is used by cells in the salivary glands, prostate, immune system, and zinc in the gut as a means of communication with other cells . [109] Zinc can be retained in metallothionein stores in microorganisms or in the intestine or liver of animals.[] Metallothionein in intestinal cells is able to adjust zinc absorption by 15-40%.[] Inadequate or excessive intake of Zinc can be harmful; Excess zinc particularly impairs copper absorption since metallothionein absorbs both metals.[]

Dietary Intake In the US, the Recommended Dietary Allowance (RDA) is 8 mg/day for women and 11 mg/day for men.[] The average intake in the US around the year 2000 was 9 mg/day for women and 14 mg/day for men.[] Oysters, lobster[] and red meat, particularly beef, lamb and liver have some of the highest zinc concentrations in foods.[] The zinc concentration in plants varies with the zinc content of the soil. When there is enough zinc in the soil, wheat (germ and bran) and various seeds (sesame, poppy, alfalfa, celery, mustard) are the food crops that contain the most zinc. [ ] Zinc is also found in beans, nuts, almonds, whole grains, pumpkin seeds, sunflower seeds, and black currants. [ ] Other sources include fortified foods and dietary supplements, which come in a variety of forms. A 1998 review concluded that zinc oxide, one of the most common dietary supplements in the United States, and zinc carbonate are nearly insoluble foods and spices that contain zinc and are poorly absorbed by the body. [] This review cited studies that found lower plasma zinc concentrations after consuming zinc oxide and zinc carbonate compared to those observed after consuming zinc acetate and sulfate salts. [ ] However, harmful over-supplementation is a problem in relatively affluent people and should probably not exceed 20 mg/day in healthy people, [110] although the US National Research Council has set a tolerable maximum intake of 40 mg/day.[ 111 ] However, for fortification, a 2003 review recommended zinc oxide in grain as inexpensive, stable, and as easily absorbable as more expensive forms.[112] A 2005 study found that various zinc compounds, including the oxide and sulfate, did not show statistically significant differences in absorption when added to corn tortillas as a tonic.[113] A 1987 study found that zinc picolinate was better absorbed than either zinc gluconate or zinc citrate.[114] However, a study

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82, published in 2008, found zinc glycinate to be the best absorbed of the four available types of dietary supplements.[115]

Deficiency Zinc deficiency is usually due to inadequate dietary intake, but it can be associated with malabsorption, acrodermatitis enteropathica, chronic liver disease, chronic kidney disease, sickle cell disease, diabetes, malignancies, and other chronic diseases. [] Mild zinc deficiency symptoms are multifaceted.[] Clinical findings include reduced growth, diarrhea, impotence and delayed sexual maturity, alopecia, eye and skin lesions, anorexia, impaired cognition, impaired defenses, defects in carbohydrate utilization, and reproductive teratogenesis.[] Milder Zinc deficiency depressed . immunity,[116] although excess zinc does as well.[] Animals on a zinc-depleted diet require twice as much feed to achieve the same weight gain as animals receiving adequate zinc.[] Groups at risk for zinc deficiency include the elderly, Children in developing countries and people with kidney failure. Zinc-chelating phytate found in grain seeds and bran cereals may contribute to zinc malabsorption.[] Despite some concerns[117], Western vegetarians and vegans are not deficient. ] Major vegetable sources of zinc include dried cooked beans, sea vegetables, fortified grains, soy products, nuts, peas, and seeds.[117] However, the phytates in many whole grains and the fiber in many foods can interfere with zinc absorption, and minor zinc intake has little-known effects. There is evidence that more than the US RDA (15 mg) of zinc per day is required by individuals whose diets are high in phytates, such as: B. some vegetarians.[117] These considerations must be balanced against the fact that there is a lack of suitable biomarkers for zinc and that the most widely used indicator, plasma zinc, has poor sensitivity and specificity.[119] Diagnosing zinc deficiency is an ongoing challenge.[] Nearly two billion people in the developing world suffer from zinc deficiency.[] In children, it causes increased infections and diarrhea, contributing to the deaths of an estimated 800,000 children worldwide each year. [] The World Health Organization recommends zinc supplementation for severe malnutrition and diarrhea.[] Zinc supplementation helps prevent disease and reduce mortality, particularly in children with low birth weight or birth retardation.[] However, zinc supplements should not be given alone, as many in are deficient in various ways in developing countries and zinc interacts with other micronutrients.[120] Agriculture Zinc deficiency is the most common micronutrient deficiency in crops; it is particularly common in soils with a high pH.[121] Zinc-deficient soils are grown on farmland in about half of Turkey and India, a third of China and most of Western Australia, and significant responses to zinc fertilization have been reported in these areas. [ ] Plants growing in zinc-poor soil are more susceptible to disease. Zinc is added to soil primarily through the weathering of rocks, but humans have added zinc through the burning of fossil fuels, mine waste, phosphate fertilizers, limestone, manure, sewage sludge, and particles from galvanized surfaces. Excess zinc is toxic to plants, although zinc toxicity is much less common.[]

Precautions Toxicity Although zinc is essential for good health, excess zinc can be harmful. Excessive zinc absorption suppresses copper and iron absorption.[] Free zinc ion in solution is highly toxic to plants, invertebrates, and even vertebrate fish.[122] The free ion activity model is well established in the literature and shows that only micromolar amounts of the free ion kill some organisms. A recent example showed that 6 micromolar killed 93% of all daphnia in the water.[123]

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83 The free zinc ion is a strong Lewis acid to the point of being corrosive. Stomach acid contains hydrochloric acid, in which metallic zinc easily dissolves into corrosive zinc chloride. Swallowing a post-1982 US penny (97.5% zinc) can damage the gastric mucosa due to the high solubility of zinc ion in gastric acid.[124] There is evidence of copper deficiency caused by low intakes of 100 to 300 mg Zn/day; A recent study found a higher number of hospitalizations for urinary tract complications compared to placebo in elderly men taking 80 mg/day.[125] The USDA RDA is 11 and 8 mg Zn/day for males and females, respectively.[] Even lower levels, closer to the RDA, may impair copper and iron utilization or adversely affect cholesterol levels.[] Zinc above 500 ppm in the soil interferes with the ability of plants to take up other essential metals such as iron and manganese. when welding galvanized materials. [ ] Zinc is a common ingredient in toothpaste that can contain anywhere from 17 to 38 mg of zinc per gram. There have been cases of disability or even death due to excessive use of these products.[126] The US Food and Drug Administration (FDA) has determined that zinc damages nerve receptors in the nose, which can cause anosmia. Reports of anosmia were also seen in the 1930s when zinc supplements were used in an unsuccessful attempt to prevent polio infections.[127] On June 16, 2009, the FDA said consumers should refrain from using zinc-based intranasal cold products and ordered that they be removed from store shelves. The FDA said smell loss can be deadly because people with smell problems can't detect gas leaks or smoke, and can't tell if food has gone bad before eating it. [] Recent research suggests that topical antimicrobial zinc pyrithione is a potent inducer of the heat shock response, which can compromise genomic integrity by inducing a PARP-dependent energy crisis in cultured human keratinocytes and melanocytes.[128]

Poisoning In 1982, the United States Mint began minting copper-coated pennies, but these were made primarily of zinc. New zinc coins have the potential for zinc poisoning, which can be fatal. One reported case of chronic ingestion of 425 cents (over 1 kg of zinc) resulted in death from gastrointestinal bacterial and fungal sepsis, while another patient ingesting 12 grams of zinc experienced only lethargy and ataxia (major lack of muscle coordination of movements ) had ).[129] Several other cases of people suffering from zinc poisoning due to ingestion of zinc coins have been reported.[130][131] Dogs sometimes ingest pennies and other small coins and need medical attention to remove the foreign object. The zinc content of some coins can cause zinc toxicity, which is often fatal in dogs, where it causes severe hemolytic anemia and also liver or kidney damage. Vomiting and diarrhea are possible symptoms.[132] Zinc is highly toxic to parrots and poisoning can often be fatal.[133] Consumption of fruit juice stored in galvanized cans has resulted in massive zinc poisoning of parrots.[]

Notes [1] http://www. infinite foundation. com/ mandala/ t_es/ t_es_agraw_zinc_frameset. htm[2] http://www. Old Asia newspaper. com/article/view/aa. 06112/ 23 [3] electronic book ISBN 978-94-007-5561-1 electronic[34] p. 46, Ancient Mining and Metallurgy in Rajasthan, SM Gandhi, Chapter 2 in Crustal Evolution and Metallogeney in the North West Indian Shield: A Festschrift for Asoke Mookherjee, M. Deb, ed., Alpha Science Int'l Ltd., 2000, ISBN 1-84265-001-7. [35] (Public domain text) [42] An East India Company ship carrying a cargo of nearly pure zinc metal from the Orient sank off the coast of Sweden in 1745. [57] Electric current will of course flow between zinc and steel, but inert anodes may be used with an external source of direct current. [87] In clinical studies, both zinc gluconate and zinc gluconate and glycine (the formulation used in lozenges) have been shown to shorten the duration of cold symptoms. The amount of glycine can vary from two to twenty moles per mole of zinc gluconate. A review of the research found that of nine controlled trials of zinc lozenges, the results were positive in four and no better than placebo in five. This review also suggested that the research is characterized by methodological issues, including differences in dosage amounts.

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84 used, and the use of self-report data. There is some evidence that zinc supplements may be more effective if taken at the first sign of cold symptoms. [100] In this one-pot reaction, bromobenzene is converted to phenyllithium by reaction with 4 equivalents of n-butyllithium, then transmetalation with zinc chloride forms diphenylzinc, which undergoes an asymmetric reaction first with the ligand MIB and then with 2-naphthylaldehyde in alcohol. In this reaction, the formation of diphenylzinc is accompanied by that of lithium chloride, which uncontrollably catalyzes the reaction to racemic alcohol without the participation of MIB. The salt is effectively removed by chelation of tetraethylenediamine (TEEDA), resulting in 92 % enantiomeric excess. [102] The role of zinc in microorganisms is discussed in particular in: [117] "Position of the American Dietetic Association and Dietitians of Canada: Vegetarian Diets". Journal of the American Dietetic Association, 2003, 06. Accessed January 4, 2007.

References Bibliography • Chambers, William and Robert (1901). Chambers' Encyclopedia: Dictionary of Universal Knowledge (http://books.google.com/?id=Rz8oAAAAAYAAJ&printsec=toc) (revised edition). London and Edinburgh: JB Lippincott Company. • Cotton, F. Albert; Wilkinson, Geoffrey; Murillo, Carlos A.; Bochmann, Manfred (1999). Advanced Inorganic Chemistry (6th ed.). New York: John Wiley & Sons, Inc. ISBN 0-471-19957-5. • CRC Contributors (2006). David R. Lide, ed. Handbook of Chemistry and Physics (http://books.google.com/?id=WDll8hA006AC&pg=PT893) (87th edition). Boca Raton, Florida: CRC Press, Taylor & Francis Group. ISBN0-8493-0487-3. • Emsley, John (2001). "Zinc" (http://books.google.com/?id=j-Xu07p3cKwC). The Building Blocks of Nature: An A to Z Guide to the Elements. Oxford, England, UK: Oxford University Press. pp. 499-505. ISBN0-19-850340-7. • Greenwood, N.N.; Earnshaw, A. (1997). Chemistry of the Elements (2nd ed.). Oxford: Butterworth-Heinemann. ISBN0-7506-3365-4. • Heiserman, David L. (1992). "Element 30: Zinc" (http://books.google.com/?id=24l-Cpal9oIC). Research into chemical elements and their compounds. New York: TAB Books. ISBN0-8306-3018-X. • Lehto, RS (1968). "Zinc". In Clifford A. Hampel. The Encyclopedia of the Chemical Elements. New York: Reinhold Book Corporation. pp. 822-830. ISBN0-442-15598-0. LCCN 68-29938 (http://lccn.loc.gov/68-29938). • US National Research Council, Institute of Medicine. (2000). Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc (http://www.nap.edu/catalog.php?record_id= 10026). National Academies Press. pp. 442-455. • Stwertka, Albert (1998). "Zinc". Guide to the Elements (Revised Edition). Oxford University Press. ISBN0-19-508083-1. • Weeks, Maria Elvira (1933). "III. Some Metals of the Eighteenth Century". The discovery of the elements. Easton, PA: Journal of Chemical Education. ISBN0-7661-3872-0.

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External Links • US National Institutes of Health Zinc Fact Sheet (http://ods.od.nih.gov/factsheets/zinc/) • Zinc History and Etymology (http://elements.vanderkrogt.net/element.php? sym=Zn) • US Geological Survey statistics and information (http://minerals.usgs.gov/minerals/pubs/commodity/zinc/index.html) • Reducing agents > Zinc (http://www.organic-chemistry. org/chemicals/reductions/zinc-zn.shtm) • American Zinc Association (http://www.zinc.org) Information on the uses and properties of zinc. • Summarize zinc safety data (http://ptcl.chem.ox.ac.uk/MSDS/ZI/zinc.html) • International Society for the Biology of Zinc (http://www.iszb.org) founded 2008 an international match. non-profit organization that brings together scientists working on the biological effects of zinc. • Zinc-UK (http://zinc-uk.org) established in 2010 to bring together UK scientists working on zinc. • Zinc (http://www.periodicvideos.com/videos/030.htm) from the Periodic Table of Videos (University of Nottingham)

Brass Brass is an alloy of copper and zinc; The proportions of zinc and copper can be varied to produce a variety of brasses with different properties.[1] In comparison, bronze is primarily an alloy of copper and tin.[2] Bronze does not necessarily contain tin, and a variety of copper alloys, including alloys containing arsenic, phosphorus, aluminum, manganese, and silicon, are commonly referred to as "bronze". The term is applied to a variety of brass instruments and the distinction is largely historical, both terms sharing a common ancestor in the term batten.

Brass matrix, along with zinc and copper samples.

Brass is a substitute alloy. It is used for decoration due to its shiny golden appearance; For applications requiring low friction such as locks, gears, bearings, handles, ammo boxes and valves; for plumbing and electrical applications; and widely used in musical instruments such as horns and bells for their acoustic properties. It is also used in zippers. Brass is commonly used in situations where non-sparking is important such as: B. in devices and tools in the vicinity of explosive gases.[4]

characteristics

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Brass's malleability and acoustic properties have made it the metal of choice for musical instruments such as trombone, tuba, trumpet, cornet, baritone horn, euphonium, tenor horn, and French horn, collectively referred to as brass. Orchestra. Although the saxophone is counted among the woodwind instruments and the harmonica among the free-reed aerophones, both are mostly also made of brass. In organ pipes of the reed family, strips of brass (called reeds) are used as reeds, striking against the shallot (or, in the case of a "free" reed, striking "through" the shallot). Although not part of the brass section, drums are sometimes made of brass as well.

Laminated and annealed brass microstructure (400x magnification)

Brass is more malleable than bronze or zinc. Brass's relatively low melting point (900 to 940 °C, 1652 to 1724 °F, depending on composition) and its flow properties make it a relatively easy material to melt. By varying the proportions of copper and zinc, the properties of brass can be changed, resulting in hard and soft brasses. The density of brass is approximately 0.303 lb/cubic inch, 8.4 to 8.73 grams per cubic centimeter.[5] Today almost 90% of all brass alloys are recycled.[6] Because brass is not ferromagnetic, it can be separated from ferrous scrap by passing the scrap near a strong magnet. Scrap brass is collected and transported to the foundry where it is melted down and made into billets. Ingots are heated and extruded to the desired shape and size. Aluminum makes brass stronger and more resistant to corrosion. Aluminum also causes a very beneficial hard layer of aluminum oxide (Al2O3) to form on the surface, which is thin, transparent and self-healing. Tin has a similar effect and is mainly used in seawater applications (ship's brass). Combinations of iron, aluminum, silicon and manganese make brass wear resistant.[7]

Lead content To improve the machinability of brass, lead is often added in concentrations of around 2%. Because lead has a lower melting point than the other components of brass, it tends to migrate to the grain boundaries in the form of globules as it cools after melting. The pattern that the globules form on the surface of the brass increases the available lead surface area, which in turn affects the degree of leaching. In addition, lead globules can be scattered over the surface during cutting operations. These effects can result in significant lead leaching from cans with comparatively low lead content.[8] Silicon is an alternative to lead; However, when silicon is used in a brass alloy, the scrap should never be mixed with leaded brass scrap due to contamination and safety concerns.[9] In October 1999, the California Attorney sued 13 major manufacturers and distributors for lead content. In laboratory tests, state investigators found that the average brass key, new or old, exceeded California's Proposition 65 limits by an average factor of 19, assuming it was handled twice a day.[10] In April 2001, manufacturers agreed to either reduce lead to 1.5% or accept a duty to warn consumers about lead levels. Faucets lined with other metals are unaffected by sedimentation and can continue to use brass alloys with a higher lead content.[11][12] Also in California, lead-free materials must be used for "all components that come in contact with the wet surface of pipe and pipe fittings, pipework and fittings". On January 1, 2010, the maximum amount of lead in "lead-free brass" in California was reduced from 4% to 0.25% lead. The common practice of using conduit for electrical grounding is discouraged as it accelerates lead corrosion.[13][14]

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Corrosion-resistant brass for harsh environments So-called dezincification-resistant brasses (DZR or DR) are used where there is a high risk of corrosion and normal brasses do not meet the standards. Applications with high water temperatures, the presence of chlorides or deviating water qualities (soft water) play an important role. DZR brass excels in water boiler systems. This brass alloy must be manufactured with great care, paying particular attention to compositional balance and the right production temperatures and parameters to avoid long-term failure.

Germicidal and antimicrobial applications

Brass sampling tap with stainless steel handle.

The copper in the brass makes the brass germicidal. Depending on the type and concentration of pathogens and the environment in which they are found, brass will kill these microorganisms within minutes to hours of contact.[15][][] The bactericidal properties of brass have been observed and confirmed in the laboratory for centuries in 1983.[16] Subsequent experiments by research groups around the world have reconfirmed the antimicrobial effectiveness of brass, as well as copper and other copper alloys (see Antimicrobial Tactile Copper Alloy Surfaces).[15][][] Copper exposed. In 2007, the US Department of Defense Telemedicine and Advanced Technology Research Center (TATRC) began studying the antimicrobial properties of copper alloys, including four types of brass (C87610, C69300, C26000, C46400), in an in-hospital clinical study conducted at several Memorial sites were Sloan-Kettering Cancer Center (New York), Medical University of South Carolina and Ralph H. Johnson VA Medical Center (South Carolina).[13][17] High-touch objects such as bed rails, bed trays, armrests, nurse call buttons, IV poles, etc. have been fitted with antimicrobial copper alloys in designated patient rooms (i.e. the “copper” rooms) in the ICU (ICU). Early results published in 2011 show that copper rooms showed a 97% reduction in surface pathogens compared to rooms without copper. This reduction is equivalent to the same level achieved by "final" cleaning programs performed after patients leave their rooms. Also, preliminary results, which are extremely important to healthcare professionals, showed that patients in copper-lined ICU rooms had a 40.4% lower risk of contracting a hospital-acquired infection than patients in copper-lined ICU rooms intensive care unit.[13] 18 [19 ] The ongoing U.S. Department of Defense research contract will also evaluate the effectiveness of copper alloy tactile surfaces in preventing the transmission of microbes to patients and the transmission of microbes from patients to touch surfaces, as well as the potential effectiveness of touching copper surfaces. alloyed components to improve indoor air quality. In the United States, the Environmental Protection Agency regulates the registration of antimicrobial products. After extensive antimicrobial testing in accordance with the agency's rigorous testing protocols, 355 copper alloys, including many brasses, killed more than 99.9% of methicillin-resistant Staphylococcus aureus (MRSA), E. coli O157:H7, Pseudomonas aeruginosa, Staphylococcus aureus, and Enterobacter aerogenes Vancomycin-resistant enterococci (VRE) within two hours of contact.[15][] Normal tanning was found not to impair antimicrobial efficacy. Antimicrobial testing also showed a significant reduction in MRSA as well as two epidemic MRSA strains (EMRSA-1 and EMRSA-16) in brass (C24000 with 80% Cu) at room temperature (22°C) within three hours. Complete killing of pathogens was observed within 4 1/2 hours. These tests were conducted under wet conditions. Removal times, while impressive, are longer than pure copper, where removal times range from 45 to 90 minutes. [ ] A new assay that mimics exposure of touch surfaces to dry bacteria was developed as this test method is believed to more closely mimic real touch surface conditions. Under these conditions, the copper alloy

Brass surfaces have been found to kill several million colony forming units of Escherichia coli within minutes. [ ] This observation, and the fact that removal times decrease as the proportion of copper in an alloy increases, is evidence that copper is the germicidal ingredient in brass and other copper alloys.[twenty] Mechanisms of antimicrobial action of copper and its alloys, including brass, are the subject of intensive and ongoing research. [][][] Mechanisms are believed to be diverse and include: 1) potassium or glutamate leakage through the outer membrane of bacteria; 2) osmotic imbalances; 3) binding to proteins that do not require or use copper; 4) Oxidative stress due to the formation of hydrogen peroxide. Research is ongoing to determine whether brass, copper and other copper alloys can help reduce cross-contamination in public facilities and reduce the incidence of nosocomial (hospital) infections in healthcare facilities. Additionally, brass alloy net cages are used in commercial aquaculture operations in Asia, South America and the USA for their antimicrobial/algicidal properties that prevent biofouling, along with their strong structural and corrosion-resistant advantages for marine environments.

Seasonal Cracking Brass is susceptible to stress corrosion cracking, particularly from ammonia or substances that contain or emit ammonia. The problem is sometimes referred to as seasonal cracking after it was first discovered in brass cartridges used for rifle ammunition in the Indian Army in the 1920s. The problem was caused by high residual stresses from the cold forming of the housings. Cracks in brass caused by ammonia attack during manufacture, along with chemical attack from trace amounts of ammonia in the atmosphere. The cartridges were stored in stables and the ammonia concentration rose during the hot summer months, causing brittle cracks. The issue was addressed by annealing the cases and storing the cartridges elsewhere.

Types of Brass • Admiralty brass contains 30% zinc and 1% tin, which inhibits zinc loss in many environments. • Each alloy typically contains 60.66% copper, 36.58% zinc, 1.02% tin and 1.74% iron. Designed for marine use due to its corrosion resistance, hardness and toughness. A typical application is the protection of ship bottoms, but more modern methods of cathodic protection have made its use less common. Its appearance resembles that of gold.[21] • Alpha brass with less than 35% zinc is malleable, cold workable and used for stamping, forging or similar applications. They contain a single phase with a face-centered cubic crystal structure. • Prince's Metal or Prince Rupert's Metal is a type of alpha brass containing 75% copper and 25% zinc. Because of its beautiful yellow color, it is used as an imitation of gold.[22] The league is named after Prince Rupert of the Rhine. • Alpha-beta brass (Muntz metal), also known as duplex brass, is 35-45% zinc and is suitable for hot work. Contains α and β' phase; Phase β' is body-centered cubic and is harder and stronger than α. Alpha-Beta brass is generally hot worked. • Aluminum Brass contains aluminum which improves its resistance to corrosion. It is used for sea water service[23] and also on euro coins (also known as 'Nordic Gold') - (see also 'Nordic Gold' below).

Brass • Arsenic brass contains added arsenic and often aluminum and is used for boiler furnaces. • Beta brass with a zinc content of 45% to 50% can only be hot worked and is harder, stronger and more suitable for casting. • Bullet brass is a brass with 30% zinc and good cold forming properties. It is used for ammo boxes. • Plain brass or riveted brass is an inexpensive standard brass containing 37% zinc for cold work. • DZR brass is a dezincification-resistant brass with a low proportion of arsenic. • Gold metal is the softest type of brass commonly available. The gold-plated metal is an alloy of 95% copper and 5% zinc and is often used for the "covers" of ammunition rounds, e.g. full metal jacket bullets. • High brass contains 65% copper and 35% zinc, has high tensile strength and is used for springs, screws and rivets. • Leaded brass is an alpha-beta brass with lead added. It has excellent machinability. • Lead-free brass, as defined by the California Assembly Bill AB 1953, contains "not more than 0.25 percent lead."[13] • Low brass is a copper-zinc alloy containing 20% zinc with a light gold color and excellent ductility; It is used for flexible metal hoses and metal bellows. • Manganese brass is a brass used primarily to make gold coins in the United States. It contains about 70% copper, 29% zinc and 1.3% manganese.[24] • Consisting of approximately 60% copper, 40% zinc and a trace amount of iron, Muntz metal is used as a coating on ships. • Marine brass, similar to military brass, contains 40% zinc and 1% tin. • Nickel brass consists of 70% copper, 24.5% zinc and 5.5% nickel and is used to make sterling coins. • Nordic gold used in the 10, 20 and 50 cent coins contains 89% copper, 5% aluminium, 5% zinc and 1% tin. • Red brass is an American term for the alloy of copper, zinc and tin known as gunmetal, and an alloy that is considered both brass and bronze. It typically contains 85% copper, 5% tin, 5% lead, and 5% zinc. and lead and the balance copper.[26] It can also refer to an ounce of metal, another alloy of copper, zinc, and tin. • Low-fat brass (tombak) contains 15% zinc. Commonly used in jewelry applications. • Tonval Brass (also called CW617N or CZ122 or OT58) is an alloy of copper, lead and zinc. Its use in seawater is not recommended as it is susceptible to dezincification.[27][28] • White brass contains over 50% zinc and is too brittle for general use. The term can also refer to certain types of German silver alloys, such as Cu-Zn-Sn alloys with high levels (typically 40%+) of tin and/or zinc, and predominantly zinc cast alloys with an addition of copper. • Yellow Brass is an American term for brass containing 33% zinc.

History Although forms of brass have been used since prehistoric times,[29] its true nature as an alloy of copper and zinc was not understood until after the Middle Ages because zinc vapor, which reacts with copper to form brass, was not recognized. . [30] The King James Bible contains many references to "bronze."[31] Shakespeare's Anglicized form of the word "bronze" can mean any alloy of bronze or copper, rather than the strict modern definition of brass. [citation needed] Early brasses may have been natural alloys produced by smelting zinc-rich copper ores.[32] In Roman times, brass was intentionally produced from metallic copper and zinc ores by the cementing process, and variations on this method continued through the mid-19th century.[33] Eventually it was replaced by cast iron, the direct alloy of copper and zinc, introduced to Europe in the 16th century.[32]

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The first copper-zinc alloys In western Asia and the eastern Mediterranean, the first copper-zinc alloys are found in small quantities from various localities in the 3rd millennium BC. known. C. Aegean, Iraq, United Arab Emirates, Kalmykia, Turkmenistan and Georgia and from the 2nd millennium B.C. Locations in West Indies, Uzbekistan, Iran, Syria, Iraq and Israel.[34] However, isolated examples of copper-zinc alloys have been known since the 5th millennium BC. known in China. it is smaller than brass produced by cementation.[35] These can be "natural alloys" produced by smelting zinc-rich copper ores under redox conditions. Many have similar tin contents to contemporary bronze artefacts, and some copper-zinc alloys may have been accidental and perhaps indistinguishable from copper.[35] However, the large number of copper-zinc alloys known today suggests that at least some were intentionally produced, and many have zinc contents in excess of 12 wt%, which would have resulted in a characteristic gold color.[35] [36] Between the 8th and 7th centuries BC C. Assyrian cuneiform tablets mention the mining of "mountain copper" and this may refer to "natural" brass.[37] Orichalcus, the ancient Greek translation of this term, was later adapted from the Latin auricalcum, meaning "golden copper," which became the standard term for brass.[38] In the fourth century B.C. C., Plato knew that orichalcum was rare and almost as valuable as gold[] and Pliny describes how aurichalcum came from Cypriot ore deposits that were exhausted by the 1st century AD. C [39]

Brass Manufacturing in the Roman World During the second half of the 1st millennium BC From about 1000 BC, the use of brass spread over a wide geographical area, from Great Britain[] and Spain[40] in the west to Iran and India in the east.[41] ] This appears to have been encouraged by exports and influences from the Middle East and the Eastern Mediterranean, where the conscious manufacture of brass from metallic copper and zinc ores was introduced.[42] The 4th century BC writer C., Theopompus, quoted by Strabo, describes how heating the land of Andeira in Turkey produced "drops of false silver", probably metallic zinc, which could be used to convert copper into Oreihalkos.[43] In the first century B.C. C. the Greek Dioscorides seems to have recognized a connection between zinc and brass ores, describing how cadmium (zinc oxide) was found in the walls of furnaces used to heat zinc or copper ore, and stating that it brass could later be used to make it.[44] In the first century B.C. C. bronze was available in sufficient quantity to mint coins in Phrygia and Bithynia [45] and after the Augustan currency reform of 23 BC. C. it was also used to make Roman dupondii and sesterces. [46] The uniform use of brass for coinage and military equipment throughout the Roman world may indicate some degree of state involvement in the industry, [47][] and brass appears to have been deliberately boycotted by Palestinian Jewish communities for its association with to be Roman culture. Authority. [] Brass was made by the cementation process, in which copper and zinc ore are heated together until zinc vapor is formed, which reacts with the copper. There is good archaeological evidence for this process and crucibles used to produce brass by cementing have been found at Roman-era sites including Xanten[] and Nidda[] in Germany, Lyon in France[48] and various locations in Great Britain. [49] Their size ranges from the size of a small acorn to large amphora-like containers, but all have high zinc content inside and are covered.[48] They show no evidence of dross or metal globules, suggesting that the zinc ores were heated to produce zinc vapor, which reacted with metallic copper in a solid state reaction. The fabric of these crucibles is porous, probably designed to prevent pressure build-up, and many have small holes in the lids that may be designed to relieve pressure [48] or to add additional zinc ores towards the end of the process. Dioscorides mentioned that zinc ores were used for both working and finishing brass, possibly indicating minor additions. Brass made during the early Roman period appears to have contained between 20 and 28 percent by weight zinc.[51] The high zinc content in coins and brass declined after the first century AD. C. and it has been suggested that this reflects the loss of zinc during recycling and therefore an interruption in the production of new brass.[52] However, it is now believed that this was probably an intentional change in composition[] and in general the use of brass increased during this period to compensate for this.

Brass made up about 40% of all copper alloys used in the Roman world by the 4th century AD.[53]

Brass Manufacturing in the Middle Ages Little is known about brass manufacturing in the centuries immediately following the fall of the Roman Empire. The disruption of the Western European trade of tin for bronze may have contributed to the growing popularity of brass in the East and between the 6th and 7th centuries AD. C. Over 90% of the copper alloy artefacts in Egypt were made of brass.[54] However, other alloys such as low-tin bronze were also used, which varied depending on local cultural attitudes, the purpose of the metal, and access to zinc, particularly between the 12th-century baptism of Christ in the baptismal font in the church. of Saint Bartholomew, Islam and the Byzantine world.[] On the contrary, Liège. The use of real brass seems to have declined in western Europe during this period in favor of weapon metals and other mixed alloys [55], however by the end of the 1st millennium AD brass artefacts are found in Scandinavian tombs in Scotland, brass was used for coin making in Northumbria used and there is archaeological and historical evidence of brass production in Germany and the Netherlands areas which would remain important centers of brass production around the world. the Middle Ages,[60] particularly Dinant: brassware is still commonly known in French as dinanterie. The baptismal font in the Church of St. Bartholomew in Liège, Belgium (before 1117) is a remarkable masterpiece of Romanesque bronze casting. The carburizing process continued to be used, but literary sources from Europe and the Islamic world seem to describe variants of a high-temperature liquid process that took place in open crucibles.[61] In Islamic cementing, zinc oxide, known as tutiya or tutty, appears to have been used instead of zinc ores to make brass, resulting in a metal with fewer iron impurities.[62] Several Islamic writers and the 13th-century Italian Marco Polo describe how it was obtained by sublimation of zinc ores and condensed into clay or iron rods, archaeological examples of which have been identified at Kush, Iran.[63] It could then be used for brass making or for medicinal purposes. In the 10th century, Yemen al-Hamdani described how spraying al-iglimiya, probably zinc oxide, onto the surface of molten copper produced tutiya vapor, which then reacted with the metal.[64] The 13th-century Iranian writer al-Kashani describes a more complex process in which tutiya was mixed with raisins and gently roasted before being placed on the surface of molten metal. A temporary lid was placed at this point, presumably to minimize the escape of zinc vapor.[65] In Europe, a similar liquid process was carried out in open crucibles, which was probably less efficient than the Roman process, and Albertus Magnus' use of the term tutty in the 13th century suggests an influence of Islamic technology.[66] The 12th-century German monk Theophilus described how preheated crucibles were filled with one-sixth calamine and powdered charcoal, then covered with copper and charcoal before being melted down, stirred, and refilled. The final product was melted and then remelted with calamine. It has been suggested that this second melting may have occurred at a lower temperature to allow more zinc to be absorbed.[67] Noting that calamine and tutty's "power" could evaporate, Albertus Magnus described how the addition of glass powder could create a film to bond it to the metal.[68] German brass crucibles from the 10th century AD are known from Dortmund. and from Soest and Schwerte in Westphalia, dated to about the 13th century, confirm the depiction of Theophilus as being open at the top, although Soest's pottery discs may have served as loose lids. what can you have

Brass was used to reduce the evaporation of zinc and has slags inside as a result of a liquid process.[69]

Brass Making in the Renaissance and in Post-Medieval Europe The Renaissance brought about major changes in both the theory and practice of brass making in Europe. From the 15th century there is evidence of renewed use of lidded cement crucibles in Zwickau, Germany.[70] These large crucibles could produce about 20 kg of brass.[71] Inside there are traces of slag and metal parts. Its irregular composition suggests that it was a low-temperature process that was not entirely liquid.[72] The crucible lids had small holes that were plugged with clay plugs towards the end of the process, presumably to maximize zinc absorption in the final stages.[73] Then triangular crucibles were used to melt the brass for casting.[74] Technical writers of the 16th century such as Biringuccio, Ercker and Agricola described a variety of techniques for carburizing brass and came closer to understanding the true nature of the process by noting that copper became heavier as it became brass and with additional Calamine became more golden . . was added.[75] Metallic zinc also became more and more common. By 1513 ingots of metallic zinc were arriving in London from India and China, and by 1550 zinc pellets condensed in the chimneys of Rammelsberg furnaces in Germany were being used to make cement brass.[76] Eventually it was discovered that metallic zinc could be alloyed with copper to make brass; a process known as popping[77] and in 1657 the German chemist Johann Faithr recognized calamine as "nothing but infusible zinc" and that zinc was a "semi-mature metal".[78] Brass, such as the 1530 brass plaque of Wightman from England, may have been made by alloying copper with zinc and contains traces of cadmium similar to those found in some zinc ingots from China. However, the cementation process was not abandoned, and as late as the early 19th century there are reports of solid-state cementation in a vaulted furnace at around 900–950 °C for up to 10 hours.[79] The European brass industry continued to thrive in the post-medieval period, fueled by innovations such as the introduction of water-powered hammers for battery manufacture in the 16th century.[80] In 1559, the German city of Aachen alone was able to produce 300,000 brass quintans annually.[80] After several false starts during the 16th and 17th centuries, the brass industry was also established in England, taking advantage of ample supplies of cheap copper, smelted in the new coal-fired reverberant furnaces.[81] In 1723, Bristol metalworker Nehemiah Champion patented the use of granulated copper, made by pouring molten metal into cold water.[82] This increased the surface area of the copper, which aided its reaction, and zinc contents of up to 33 wt% have been reported using this new technique.[83] In 1738, Nehemiah's son, William Champion, patented a technique for the first industrial-scale distillation of metallic zinc, known as down-distillation or "the English process." of brass and the production of high-zinc copper alloys, which would have been difficult or impossible to produce by cementing, for use in expensive items such as scientific instruments, clocks, brass buttons, and costume jewelry.[85] However, Champion continued to use the cheaper calamine carburizing method to produce low-zinc brass [85] and archaeological remains of honeycomb carburizing furnaces were identified in his work at Warmley in the late 18th century. Developments in cheaper zinc distillation, such as the horizontal furnaces of John-Jaques Dony in Belgium and lower zinc tariffs[86], as well as the demand for corrosion-resistant high-zinc alloys, increased the popularity of distillation and , as a result, cementing was abandoned in the mid-19th century largely abandoned.

Messing

References [1] Engineering Designer 30(3): 6-9, May-June 2004 [2] Machinery Handbook, Industrial Press Inc, New York, Issue 24, p. 501 [4] SST replies: Non-sparking tools/ non-sparking. html (http://www.ccohs.ca/oceanswers/safety_haz/hand_tools/non-sparking.html). CCOHS.CA (2011-06-02). Accessed 9/12/2011. [9] Chase Brass & Copper Company, Inc. (https://www.chasebrass.com/productline/index_greendot.jsp). Chase bass. with. Accessed 9/12/2011. [10] News and Alerts - California Department of Justice - Office of the Attorney General (http://ag.ca.gov/newsalerts/print_release.php?id=529), 12 October 1999 [11] News and Alerts Alerts – California Department of Justice – Office of the Attorney General (http://ag.ca.gov/newsalerts/print_release.php?id=1077), April 27, 2001 [12] San Francisco Superior Court, People v . State of California. Ilco Unican Corp. et al. (#307102) and Mateel Environmental Justice Foundation v. US. Ilco Unican Corp. et al. (No. 305765) [13] Assembly Bill AB 1953 – Bill Analysis (http:// info. sen. ca. gov/ pub/ 05-06/ bill/ asm/ ab_1951-2000/ ab_1953_cfa_20060818_134053_sen_floor . html). Info.sen.ca.gov. Accessed 9/12/2011. [14] Requirements for California Low-Lead Plumbing Products (http://www.dtsc.ca.gov/PollutionPrevention/upload/Lead-in-Plumbing-Fact-Sheet.pdf), data sheet, Dept. Toxic Substance Control Office, State of California, February 2009 [15] EPA Registers Copper-Based Alloy Products (http://www.epa.gov/opp00001/factsheets/copper-alloy-products.htm), May 2008 [16] Kuhn, Phyllis J (1983) Porta poms: a source of nosocomial infections? (http://members.vol.at/schmiede/MsgverSSt.html) Diagnostic Medicine [17] Copper touch surfaces. Congress funds testing of copper's ability to kill harmful pathogens (http://www.coppertouchsurfaces.org) [18] TouchSurfaces Clinical Trials: Research Proves (http://www.coppertouchsurfaces.org/press/releases/20110701). html) . Coppertouchsurfaces.org. Accessed 9/12/2011. [19] First World Health Organization International Conference on Infection Prevention and Control (ICPIC) in Geneva, Switzerland, 1 July 2011 [20] Michels, H.T., Wilks, S.A., Noyce, J.O. and Keevil, C.W., 2005, Copper Alloys for the Control of Human Infectious Diseases, Materials Science and Technology Conference: Copper for the 21st Century Symposium, 25-28. September, Pittsburgh, PA [21] Simons, EN. (1970). A Dictionary of Alloys, Cornell University [22] National Pollutant Inventory - Copper and Compounds Data Sheet (http://www.npi.gov.au/database/substance-info/profiles/27.html). npi.gov.au. Accessed 9/12/2011. [23] Material property data: aluminum brass (http://www.makeitfrom.com/data/?material=Aluminum_Brass). Makeitfrom. with. Accessed 9/12/2011. [24] Manganese brass: definition from (http://www.answers.com/topic/manganese-brass). Answer. with. Accessed 9/12/2011. [28] Print Design 1 (http://www.aquafax.co.uk/aquafax_v2/html/images/aceimages/TechData.pdf). (PDF) Accessed on 09/12/2011. [29] Thornton, C.P. (2007) "Made of Brass and Bronze in Prehistoric Southwest Asia" in La Niece, S. Hook, D. and Craddock, P.T. (Ed.) Metals and Mines: Studies in Archaeometallurgy London: Archetype Publications. ISBN 1-904982-19-0 [30] by Ruette, M. (1995) "From Contrefei and Speauter to Zinc: Developing Understanding of the Nature of Zinc and Brass in Post-Medieval Europe" in Hook, DR. and Gaimster, D.R.M (ed.) Trade and Discovery: The Scientific Study of Artifacts from Post-Medieval Europe and Beyond London: Occasional Documents of the British Museum 109 [31] Cruden's Complete Concordance p. 55 [32] Craddock, P.T. and Eckstein, K (2003) "Production of Brass in Antiquity by Direct Reduction" in Craddock, P.T. and Lang, J. (eds.) Mining and metal production through the ages London: British Museum pp. 226-7 [33] Rehren and Martinon Towers 2008, pp. 226-7. 170–5 [34] Thornton 2007, p. 189–201 [35] Craddock and Eckstein 2003 p. 217 [36] Thornton, CP and Ehlers, CB (2003) "Early Brass in the Ancient Near East" in IAMS Newsletter 23, p. 27–36 [37] Bayley 1990, p. 8 [38] Rehren and Martinon Towers 2008, p. 169 [39] Pliny the Elder Historia Naturalis XXXIV 2 [40] Montero-Ruis, I and Perea, A (2007) "Brass in the early metallurgy of the Iberian Peninsula" in La Niece, S. Hook, D. y Craddock, P.T. (ed.) Metals and Mines: Studies in Archaeometallurgy London: Archetype: p. 136–40 [41] Craddock and Eckstein 2003, p. 216–7 [42] Craddock and Eckstein 2003, p. 217 [43] Bayley 1990, p. 9 [44] Craddock and Eckstein 2003, p. 222-4. Bayley 1990, p. 10. [45] Craddock, PT. Burnett, A. and Preston K. (1980) "Hellenistic Copper-Based Conage and the Origins of Brass" in Oddy, WA (eds.) Scientific Studies in Numismatics Occasional Documents from the British Museum 18 p. 53–64 [46] Caley, ER (1964) Orichalcum and Related Old Leagues New York; American Numismatic Society

Brass [47] Bayley 1990, p. 21 [48] Rehren and Martinon Towers 2008, p. 170–1 [49] Bayley 1990 [50] Craddock and Eckstein 2003, p. 224 [51] Craddock and Eckstein 2003, 224 [52] Caley 1964 [53] Craddock 1978, p. 14 [54] Craddock, P.T. La Niece, SC and Hook, D. (1990) "Brass in the Medieval Islamic World" in Craddock, PT (eds.) 2000 Zinc and Brass Years London: British Museum p. 73 [55] Bayley 1990, p. 22 [56] Eremin, K. Graham-Campbell, J. and Wilthew, P. (2002) "Analysis of Copper Alloy Artifacts from Pagan Norse Graves in Scotland" in Biro, K.T. and Eremin, K. (eds.) Proceedings of the 31 International Symposium on Archaeometry Oxford: Archaeopress BAR pp. 342-9 [57] Gilmore, G.R. and Metcalf, DM (1980) "A league of coins from Northumbria até Meads of the ninth century" in Metcalf, D and Oddy, W. Metallurgy in Numismatics 1 p. 83–98 [58] Rehren 1999 [59] Dia 1990, p. 123–150 [60] Dia 1990, p. 124–33 [61] Craddock and Eckstein 2003, p. 124-33. 224-5 [62] Craddock et al. 73-6 [64] Craddock et al. 75 [65] Craddock et al. 76 [66] Rehren, T. (1999) "Same... but different: a justaposition of Roman and Medieval Brass in Europe" in Young, S.M.M. (Eds.) Metais and Antiquity Oxford: Archaeopress pgs. 252–7 [67] Craddock and Eckstein 2003, 226 [68] Rehren and Martinon Towers 2008, p. 176–8 [69] Rehren and Martinon Towers 2008, p. 176-8. 173 -5 [70] Martinon Towers and Rehren 2002, p. 95–111 [71] Martinon Towers and Rehren 2002, p. 105–6 [72] Martinon Towers and Rehren 2002, p. 103 [73] Martinon Towers and Rehren 2002, p. 104 [74] Martinon Towers and Rehren 2002, p. 100 [75] Martinon Towers and Rehren 2008, 181–2, de Ruette 1995 [76] de Ruette 1995, 198 [77] Craddock and Eckstein 2003, 228 [78] de Ruette 1995, 198–9 2003, 226–7. [80] Day 1990, p. 131 [81] Dia 1991, p. 135–44 [82] Dia 1990, p. 138 [83] Craddock and Eckstein 2003, p. 227 [84] Dia 1991, p. 179-81 [85] Dia 1991, p. 183 [86] Dia 1991, p. 186-9 [87]. 186-9. 192–3, Craddock and Eckstein 2003, p. 228

Bibliografia • Bayley, J. (1990) „The Production of Brass in Antiquity with Particular Reference to Roman Britain“ von Craddock, P.T. (Hrsg.) 2000 Jahre Zink und Messing London: British Museum • Craddock, P.T. e Eckstein, K (2003) „Produção de latão antigo por redução direta“ em Craddock, P.T. e Lang, J. (Hrsg.) Bergbau und Metallproduktion im Wandel der Zeit London: British Museum • Day, J. (1990) „Brass and Zinc in Europe from the Middle Ages to the Nineteenth Century“ in Craddock, P.T. (Hrsg.) 2000 Years of Zinc and Brass London: British Museum • Day, J (1991) „Copper, Zinc and Brass Production“ in Day, J und Tylecote, R.F (Hrsg.) The Industrial Revolution in Metals London: The Institute of Metais • Martinon Torres, M. und Rehren, T. (2002). Metalurgia Histórica 36 (2): 95–111.

Lettland • Rehren, T. und Martinon Torres, M. (2008) „Imitating nature: European brassmaking between craft and science“ in Martinon-Torres, M. und Rehren, T. (Hrsg.) Material: Short Coast Press

Externe Links • Brass.org (http://www.brass.org)

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Payment AG 47 payment

Palladium ← Silber → CadmiumCu ↑

Ag ↓ Au Silver on the periodic table Appearance bright white metal

Electrolytically refined silver General characteristics Name, symbol, number

payment, payment, 47

pronunciation

/sɪlvar/

item category

transition metal

group, period, block

11, 5, diam

standard atomic weight

107.8682

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97 Electronic configuration

[Kr] 4d10 5s1 2, 8, 18, 18, 1

discovery of history

before 5000 BC Chr. C. Physical properties

Phase

fest

Density (near room temperature)

10,49 g·cm−3

Density of the liquid in m.p.

9,320 g·cm−3

fusion point

1234,93 K, 961,78 °C, 1763,2 °F

boiling point

2435K, 2162°C, 3924°F

heat of fusion

11.28 kJ·mol−1

heat of vaporization

250.58 kJ·mol−1

molar heat capacity

25,350 J mol-1 K-1 vapor pressure

P (Pa)

100

1 k

10 thousand 100 thousand

in T (K) 1283 1413 1575 1782 2055 2433 Atomic Properties Oxidation States

1, 2, 3 (amphoteres Oxid)

electronegativity

1.93 (Pauling Scale)

ionization energies

1st: 731.0 kJ mol-1 2nd: 2070 kJ mol-1 3rd: 3361 kJ mol-1

Atomic func

144 hours

covalent ray

145±17h

Radio Van der Waals

172h Miscellaneous

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98 crystal structure

face-centered cubic

magnetic request

diamagnetic

Electrical resistance

(20°C) 15,87 nΩ·m

thermal conductivity

429W·m−1·K−1

thermal conductivity

(300 K) 174 mm²/s

thermal expansion

(25 °C) 18,9 µm·m−1·K−1

[1]

Speed of sound (thin bar) (r.t.) 2680m s−1 Modulus of elasticity

83 GPa

Schneidmodul

30 GPa

Volumenmodul

100 GPa

poison ratio

0,37

Mohs hardness

2.5

Dureza Vickers

251 MPa

Brinell hardness

206 MPa

CAS registration number

7440-22-4 Stabilste Isotope

Main article: Isotopes of silver iso 105

Agriculture

106m

Agriculture

take care of yourself

sin

Silber 51.839 %

107

108m

Agriculture

sin

Silber 48.161 %

109 111

Agriculture

sin

Half-life MD SD (MeV) 41.2 d

8.28 dia

0,344, 0,280, 0,644, 0,443

0,511, 0,717, 1,045, 0,450

DP105

106

107

Ag is stable at 60 neutrons

418 years

108

THE

0,109

108

0,433, 0,614, 0,722

Agriculture

109

Ag is stable with 62 neutrons.

7.45 dia

b−

1.036, 0.694

0,342

111

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Silver is a chemical element with the chemical symbol Ag (Greek: άργυρος arguros, Latin: argentum, both from the Indo-European root *arg- for "grey" or "bright") and atomic number 47. A soft, white, and lustrous transition metal It has the highest electrical conductivity of any element and the highest thermal conductivity of any metal. The metal occurs naturally in its pure, free form (native silver), as an alloy with gold and other metals, and in minerals such as argentite and chloroargyrite. Most silver is a by-product of refining copper, gold, lead, and zinc. Silver has long been prized as a precious metal, used in coins to make high quality ornaments, jewellery, cutlery and utensils (hence the term cutlery) and as a financial investment in the form of gold coins and bullion. The silver metal is used industrially in electrical contacts and conductors, in mirrors and in the catalysis of chemical reactions. Its compounds are used in photographic films and dilute solutions of silver nitrate and other silver compounds as disinfectants and microbicides (oligodynamic action). Although many of silver's antimicrobial medicinal uses have been replaced by antibiotics, research into its clinical potential continues.

Properties Silver is made from the lightest elements in the universe by the r-process, a form of nuclear fusion thought to occur in certain types of supernova explosions. This creates many elements heavier than iron, including silver.[2] Silver is a very ductile, malleable (slightly harder than gold), monovalent coinage metal with a brilliant white metallic luster that can be highly polished from 1000 oz t (~31 kg) of silver bullion. It has the highest electrical conductivity of any metal, even better than copper, but its higher cost has prevented it from being widely used in place of copper for electrical purposes. An exception to this is in high frequency engineering, particularly at VHF and higher frequencies, where silver plating is widely used to improve the electrical conductivity of parts including cables. During World War II, 13,540 tons were used in electromagnets to enrich uranium in the US, primarily due to wartime copper shortages.[3][4][5] Of the metals, pure silver has the highest thermal conductivity (nonmetallic diamond-shaped carbon and superfluid helium II are the highest) and one of the highest optical reflectivities. [ ] (Aluminum slightly outperforms silver in parts of the visible spectrum, and silver is a poor UV reflector.) Silver is the best conductor of heat and electricity of any metal on the periodic table. Silver also has the lowest contact resistance of any metal. Silver halides are light sensitive and are known for their ability to record a latent image that can be chemically developed. Silver is stable in pure air and water, but darkens when exposed to air or water containing ozone or hydrogen sulfide, the latter forming a black layer of silver sulfide that can be cleaned with dilute hydrochloric acid.[3] The most common oxidation state of silver is +1 (e.g. silver nitrate, AgNO3); the rarer +2 compounds (e.g. silver(II) fluoride, AgF2) and the even rarer +3 (e.g. potassium(III) tetrafluoroargentate, KAgF4) and even +4 compounds (e.g. B. Potassium(IV), K2AgF6)[6] are also known.

Isotopes Natural silver consists of two stable isotopes, 107Ag and 109Ag, with 107Ag being slightly more abundant (51.839% of natural abundance). Silver isotopes are almost equally common, something rare on the periodic table. The atomic weight of silver is 107.8682(2) g/mol.[7][8] 28 radioisotopes were characterized, the most stable being 105Ag with a half-life of 41.29 days, 111Ag with a half-life of 7.45 days and 112Ag with a half-life of 3.13 hours. This element has numerous metastases, the most stable being 108mAg (t1/2 = 418 years), 110mAg (t1/2 = 249.79 days) and 106mAg (t1/2 = 8.28 days). All of the remaining radioactive isotopes have half-lives of less than one hour, and most of them have half-lives of less than three minutes.

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The relative atomic mass of silver isotopes ranges from 93.943 (94 Ag) to 126.936 (127 Ag); [9] The main decay mode before the most abundant stable isotope, 107Ag, is electron capture and the main mode after is beta decay. The primary decay products before 107Ag are isotopes of palladium (element 46) and the primary decay products after that are isotopes of cadmium (element 48). The palladium isotope 107Pd decays by beta emission to 107Ag with a half-life of 6.5 million years. Iron meteorites are the only objects with a high enough palladium to silver ratio to produce measurable fluctuations in 107Ag abundance. Radiogenic 107Ag was first detected in the Santa Clara meteorite in 1978.[10] The discoverers suggest that the coalescence and differentiation of small iron-core planets may have occurred 10 million years after a nucleosynthetic event. The 107Pd-107Ag correlations observed in bodies that have clearly melted since the formation of the Solar System must reflect the presence of unstable nuclides in the early Solar System.[11]

Compounds Metallic silver readily dissolves in nitric acid (HNO 3 ) to form silver nitrate (AgNO 3 ), a clear crystalline solid that is sensitive to light and readily soluble in water. Silver nitrate is used as a starting point for the synthesis of many other silver compounds, as an antiseptic, and as a yellow stain for glass in stained glass. Silver metal does not react with sulfuric acid, which is used in jewelry making to clean and remove copper oxide deposits from silver items after silver has been soldered or annealed. Silver readily reacts with sulfur or hydrogen sulfide H 2 S to produce silver sulfide, a dark-colored compound known to tarnish silver coins and other items. Ag 2S silver sulfide also forms silver filaments when silver electrical contacts are used in a hydrogen sulfide rich atmosphere. 4Ag + O2 + 2H2S → 2Ag2S + 2H2O Silver chloride (AgCl) is precipitated from silver nitrate solutions in the presence of chloride ion, and the other silver halides used in the preparation of photographic emulsions are obtained similarly. B. using bromide or iodide salts. Silver chloride is used in glass electrodes for pH testing and potentiometric measurements and as a clear putty for glass. Silver iodide has been used in attempts to seed clouds to produce rain.[3] Silver halides are very insoluble in aqueous solutions and are used in gravimetric analysis methods. Cessna 210 equipped with a cloud seeding silver iodide generator

Silver oxide (Ag 2 O), formed when silver nitrate solutions are treated with a base, is used as the positive electrode (anode) in watch batteries. silver carbonate

(Ag 2CO 3) precipitates when silver nitrate is treated with sodium carbonate (Na 2CO[] 3). 2 AgNO3 + 2 OH− → Ag2O + H2O + 2 NO3− 2 AgNO3 + Na2CO3 → Ag2CO3 + 2 NaNO3 Silver fulminate (AgONC), a powerful touch-sensitive explosive used in detonators, is made by reacting metal coated with acidic nitric acid is, manufactured. Acid in the presence of ethanol (C 2H 5OH). Other dangerously explosive silver compounds are silver azide (AgN

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3),

formed by the reaction of silver nitrate with sodium azide (NaN 3) and silver acetylide formed when silver reacts with acetylene gas. [12]

Latent images formed in silver halide crystals are revealed by treatment with alkaline solutions of reducing agents such as hydroquinone, methol (4-(methylamino)phenol sulfate) or ascorbate which reduce the halide exposed to metallic silver. Alkaline silver nitrate solutions can be reduced to metallic silver by reducing sugars such as glucose, and this reaction is used in silver-plated glass mirrors and in glass Christmas ornaments. Silver halides are soluble in sodium thiosulfate (Na 2 S 2 O 3 ) solutions, which is used as a photographic fixer to remove excess silver halide from photographic emulsions after image development. [] Metallic silver is attacked by strong oxidizing agents such as potassium permanganate (KMnO 4) and potassium dichromate (K 2Cr 2O 7) and in the presence of potassium bromide (KBr); These compounds are used in photography to lighten silver images, converting them to silver halides that can be fixed with thiosulfate or redeveloped to intensify the original image. In the presence of an excess of cyanide ions, silver forms water-soluble cyanide complexes (silver cyanide). Silver cyanide solutions are used in silver electroplating.[]

Applications Many known uses of silver relate to its precious metal properties, including currency, ornaments and mirrors. The contrast between its bright white color and other supports makes it very useful for fine arts. It has also long been used to add monetary value to objects (such as silver coins and bullion bars) or to create objects that symbolize high social or political status. Silver salts have been used since the Middle Ages to create yellow or orange colors in stained glass, and more complex decorative color reactions can be created by incorporating silver metal into blown, kiln-formed, or flame-worked glass.[13]

Currency Silver in the form of electrum (an alloy of gold and silver) was minted around 700 BC. minted to make money. C. From the Lydians. Later, silver was refined and minted in its pure form. Many nations used silver as the basic unit of monetary value. In the modern world, silver bullion has the ISO currency code XAG. The name of the pound sterling (£) reflects the fact that it originally represented the value of a sterling silver tower weight; other historical currencies such as the French pound have similar etymologies. During the 19th century, the bimetallism that prevailed in most countries was shaken by the discovery of large silver deposits in America; Fearing a sharp fall in the value of silver, and with it the currency, most states switched to the gold standard in 1900. In some languages like Sanskrit, Spanish, French and Hebrew, the same word means both silver and money. The 20th century saw a gradual move toward fiat money, with most of the world's monetary system losing its connection to precious metals after Richard Nixon removed the US dollar from the gold standard in 1971; The last gold-backed currency was the Swiss franc, which became a fiat-only currency on May 1, 2000. During the same period, silver gradually fell out of use in circulation coins. In 1964, the United States stopped minting silver coins and coins. They minted their last circulating silver coin in 1970 at 40% half dollars. The Royal Canadian Mint still produces many collectible silver coins in various dollar denominations.

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Silver is used as currency by many people and is legal tender in the US state of Utah.[14] Silver coins and gold bullion are also used as investments to hedge against inflation and devaluation.

Jewelery and cutlery Jewelery and cutlery are traditionally made from sterling silver (standard silver), an alloy of 92.5% silver and 7.5% copper. In the US, only an alloy of at least 90.0% fine silver may be marketed as "silver" (hence often stamped 900). Sterling silver (stamped 925) is harder than pure silver and has a lower melting point (893°C) than pure silver or pure copper.[3] Britannia silver is an alternative standard of superior quality at 95.8% silver and is commonly used in the manufacture of silver cutlery and forged plates. The addition of germanium creates the patented modified alloy Argentium Sterling Silver with improved properties, including fire resistance. Sterling silver jewelry is usually plated with a thin layer of 0.999 fine silver to give the item a shiny finish. This process is called "blinking". Silver jewelry can also be plated with rhodium (for a shiny look) or gold (to create gold plated silver). Silver is a component of almost all karat gold alloys and karat gold solders, giving the alloys a lighter color and greater hardness. 8.3% silver or copper or other metals. [ ] The training and organization of the goldsmith's guild historically included goldsmiths, and the two trades still overlap extensively. Unlike blacksmiths, goldsmiths do not shape metal while it is still glowing, but rather work at room temperature with carefully placed and gently placed hammer blows. The essence of goldsmithing is taking a flat piece of metal and turning it into a useful object using various hammers, stakes, and other simple tools.[15]

Flat silver bowl, Persian, 6th century B.C. C. (Achaemenid). The deeper indentations represent lotus flowers, an Egyptian motif. Collections of the Walters Art Museum.

Silver plate with the goddess Minerva from the Treasury of Hildesheim, 1st century BC.

Although goldsmiths are specialized and work primarily with silver, they also work with other metals such as gold, copper, steel and brass. They make jewelry, silverware, armor, vases, and other artistic items. Because silver is such a malleable metal, silversmiths have a wide range of choices in how they prefer to work the metal. Historically, goldsmiths were mostly known as goldsmiths, usually belonging to the same guild. There are no guilds in the Western Canadian silver tradition; However, peer mentoring is becoming a method of professional learning within a craft community.[16] Traditionally, goldsmiths mainly made "cutlery" (silverware, dishes, bowls, candlesticks, etc.). It is only more recently that goldsmithing has evolved primarily into a jewelry profession as there is much less handmade solid silver tableware being produced today.

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Dentistry Silver can be alloyed with mercury at room temperature to produce amalgams, which are often used for dental fillings. To create dental amalgam, a mixture of silver powder and other metals such as tin and gold is mixed with mercury to form a hard paste that can be molded into the shape of a cavity. Dental amalgam reaches its initial hardness within a few minutes and hardens within hours.

Photography and Electronics Photography consumed 30.98% of silver in 1998 in the form of silver nitrate and silver halides. In 2001, 23.47% was used for photography, while 20.03% was used for jewelry, 38.51% for industrial purposes, and only 3.5% for coins and medals. The use of silver in photography quickly declined due to reduced consumer demand for color film due to the advent of digital technology. since 2007, of the 907 million ounces of silver on offer, only 117.6 million ounces (13%) have been consumed by the photographic industry, approximately 50% of the amount used in photography in 1998. In 2010 supply increased by approximately 10% to 1,056.8 million ounces, of which 72.7 million ounces were used in the photographic industry, a 38% decrease from 2007.[17] Some electrical and electronic products use silver even when blackened because of its excellent conductivity. The prime example of this are high-quality HF connectors. The increased conductivity is also used in HF technology at VHF and higher frequencies, where conductors often cannot be dimensioned within 6% due to fitting requirements, e.g. B. cavity filter. As another example, circuit boards and RFID antennas can be made with silver inks,[3] [18] and computer keyboards use silver electrical contacts. Silver Cadmium Oxide is used in high voltage contacts because of its ability to resist arcing. Some manufacturers produce audio interconnect cables, speaker cables and power cables with silver conductors, which have 6% higher conductivity than traditional copper conductors of identical dimensions, but cost much more. Although controversial, many hi-fi enthusiasts believe that silver-plated cables improve sound quality. Another use is in high capacity silver-zinc and silver-cadmium batteries.

Mirrors and optics Mirrors that require excellent visible light reflectivity are usually made with silver as the reflective material in a process called plating, although traditional mirrors have an aluminum backing. Silver is sputtered onto the glass along with other optically transparent layers, creating low-E coatings used in high-performance insulating glass. The amount of silver used per window is small because the silver layer is only 10 to 15 nanometers thick.[19] However, the amount of silver coated glass worldwide is in the hundreds of millions of square meters per year, resulting in silver consumption on the order of 10 cubic meters or 100 tons/year. The silver color seen in architectural glass and tinted vehicle windows is created by sputtering chrome, stainless steel or other alloys. Silver is rarely used as a reflector in telescope mirrors, where aluminum is generally preferred because it is cheaper and less prone to tarnishing and corrosion.[20] Silver is the reflective coating of choice for solar reflectors.[21]

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Other Industrial and Commercial Uses Silver and silver alloys are used in the construction of many types of high quality brass instruments.[22] Flutes in particular are commonly made of silver alloy or plated, both for their appearance and for the surface friction properties of silver. Silver's catalytic properties make it ideal for use as a catalyst in oxidation reactions, for example the production of formaldehyde from methanol and air using silver sieves or crystallites containing at least 99.95 percent by weight silver. Silver (on a suitable support) is probably the only currently available catalyst for converting ethylene to ethylene oxide (later hydrolyzed to ethylene glycol used to make polyesters), an important industrial reaction. It is also used in the Oddy test to detect reduced sulfur compounds and carbonyl sulfides.

This Yanagisawa A9932J Alto Saxophone features a solid silver bell and neck with a solid phosphor bronze body. Bell, neck and key bell are elaborately engraved. It was manufactured in 2008.

Because silver readily absorbs free neutrons, it is commonly used to make fission chain reaction control rods in pressurized water nuclear reactors, usually in the form of an alloy containing 80% silver, 15% indium, and 5% cadmium. Used in the manufacture of solders and brazing alloys, silver as a thin layer on bearing surfaces can provide a significant increase in abrasion resistance and reduce wear under heavy loads, especially versus steel.

Biology Silver stains are used in biology to increase the contrast and visibility of cells and organelles under the microscope. Camillo Golgi used silver stains to study cells in the nervous system and Golgi apparatus.[24] Silver stains are used to stain proteins in gel electrophoresis and polyacrylamide gels as primary stains or to improve the visibility and contrast of the colloidal gold stain.[25]

Medicinal Medicinal uses of silver include incorporation into wound dressings and use as an antibiotic coating on medical devices. Dressings containing silver sulfadiazine or silver nanomaterials can be used to treat external infections. Silver is also used in some medical applications such as urinary catheters and endotracheal breathing tubes, where preliminary evidence shows that it is effective in reducing catheter-related UTIs and ventilator-associated pneumonia, respectively.[26] The silver ion (Ag+) is bioactive and in sufficient concentration easily kills bacteria in vitro. Silver and silver nanoparticles are used as antimicrobial agents in a variety of industrial, healthcare, and household applications.[27]

Investing Silver coins and gold bars are used for investing. Mints sell a wide range of silver products to investors and collectors. Several institutions offer safekeeping for large physical silver investments, and many types of silver investments can be made in the stock markets, including mining stocks. Silver bars are sold in a variety of ounces and come from various mints and mines around the world. Silver coins and gold bars are typically 99.9% pure and are marked ".999".

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Clothing Silver inhibits the growth of bacteria and fungi in clothing such as socks, so it is sometimes added to reduce odor and the risk of bacterial and fungal infections. It is incorporated into clothing or shoes by incorporating or silver-coating silver nanoparticles into the polymer that makes up the threads.[28][29] Silver loss during laundering varies between textile technologies and the resulting environmental impact is not yet fully understood.[30][31]

History Silver has been used in jewelry and utensils, in commerce and as the basis of many monetary systems for thousands of years. For a long time, its value as a precious metal was only surpassed by gold. The word "silver" appears in Anglo-Saxon in several spellings, such as B. Seolfor and Siolfor. A similar form is seen in all Germanic languages (compare the Old High German syllable and whistle). The chemical symbol Ag comes from the Latin word for "silver", argentum (compare Greek άργυρος, árgyros), from the Indo-European root *arg-, meaning "white" or "bright". Silver has been known since ancient times. Slag heaps mentioned in the book of Genesis found in Asia Minor and on the Aegean islands indicate that as early as the fourth millennium BC BC silver was separated from lead by open pit mining.[3]

The crescent moon has been used to represent silver since ancient times.

The stability of Roman currency depended in large part on the supply of bullion, which Roman miners produced on an unprecedented scale prior to the discovery of the New World. With peak production of 200 t per year, an estimated 10,000 t of silver was circulating in the Roman economy by the mid-2nd century AD, five to ten times the combined amount of silver available in medieval Europe and the Caliphate. around. 800 AD [32] [33] Treasury officials in the Roman Empire were concerned about the loss of silver to pay for the much-demanded silk from Sinica (China). In Laureion 483 B.C. BC mines made. [34] In the Gospels, Jesus' disciple Judas Iscariot is famous for accepting a bribe of 30 pieces of silver from the religious leaders of Jerusalem in order to hand Jesus of Nazareth over to the soldiers of the high priest Caiaphas.[35] The Imperial Chinese For most of its history, silver was used primarily as a medium of exchange. In the 19th century, threats to Britain's balance of payments from Chinese merchants demanding silver for tea, silk and china led to the Opium War as Britain had to find a way to resolve the payment imbalance. , and decided to do this by selling opium produced in their colony of British India to China.[36] The recorded use of silver to prevent infection dates back to ancient Greece and Rome; It was rediscovered in the Middle Ages when it was used for various purposes, such as disinfecting water and food during storage, and treating burns and wounds as a dressing. In the 19th century, seafarers on long sea voyages placed silver coins in barrels of water and wine to keep the liquid drinkable. Pioneers in America used the same idea as they advanced from coast to coast. Silver solutions were approved by the US Food and Drug Administration for use as an antibacterial agent in the 1920s. [citation needed] Under certain circumstances, Islam allows Muslim men to wear silver jewelry. 37] In the Americas, high-temperature silver and lead cupellation technology was developed by pre-Inca civilizations from 60 to 120 AD.[38]

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Folklore In European folklore, silver was considered a mystical object and, like cold iron, was considered somewhat abominable in terms of supernatural aspects. The myth of silver's mystical properties is deeply rooted in human history. Silver is believed to have purifying effects, a belief that probably arose from the observation that water stored in a silver jug took longer to form foam; In modern times, silver has been shown to have antibacterial properties. As a precious metal similar to gold, it is often credited with something like the "pure incorruptible purity" of silver. Because of this, silver is almost always thought of as the good side of magic (and items made from it can also be Made of Goodness). In some Neo-Pagan traditions, silver is the metal associated with the powers of the moon, symbolizing the light of the moon and representing the feminine energies of the triple goddess. According to Francis Barrett's The Magician, it makes the wearer "gentle, agreeable, cheerful, and honest, removing all malice and malevolence; it gives security in a journey, increases the body's wealth and health, wards off enemies.” In ritual, silver is believed to promote harmonious energy and a sense of peace. In folklore, and now in later fiction, the metal is said to do many things from channeling magic to stopping evil (including repelling or harming vampires and werewolves), making magic mirrors, and transmuting water into a "healing potion". . Throughout mythology and subsequent fiction, silver has been a common protection against evil. Since the Middle Ages, it was believed that silver, especially when blessed, repelled or harmed certain supernatural beings (including vampires).

World War II During World War II, copper shortages led to silver being replaced in many industrial applications. The United States government loaned silver from its vast reserves in the West Point vaults to a wide range of industrial users. A very important use was the power rails of the new aluminum factories needed for the manufacture of airplanes. During the war, many electrical connections and switches were silver-plated. Another use was for aircraft main rod bearings and other types of bearings. Because silver can replace tin in solder in smaller quantities, a large amount of tin has been freed up for other uses, replacing state silver. Silver was also used as a reflector in headlights and other types of lights. A high tech application of silver was for conductors at Oak Ridge National Laboratory used in calutrons to isolate uranium as part of the Manhattan Project. (After the war ended, silver was returned to the coffers.) [39] Silver was used in nickel during the war to preserve that metal for use in steel alloys. []

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Occurrence and extraction Silver occurs natively, as an alloy with gold (electro) and in ores containing sulphur, arsenic, antimony or chlorine. Minerals include argentite (Ag2S), chlorargyrite (AgCl), including horn silver, and pyrargyrite (Ag3SbS3). The main sources of silver are copper, cupro-nickel, lead and lead-zinc ores mined in Peru, Bolivia, Mexico, China, Australia, Chile, Poland and Serbia.[3] Peru, Bolivia and Mexico have been mining silver since 1546 and remain the world's top producers. The main silver producing mines are Cannington (Australia), Fresnillo (Mexico), San Cristóbal (Bolivia), Antamina (Peru), Rudna (Poland) and Peñasquito (Mexico). 2015 are Pascua Lama (Chile), Navidad (Argentina), Jaunicipio (Mexico), Malku Khota (Bolivia)[40] and Hackett River (Canada).[]

Time trend of silver production.

The metal is produced primarily as a by-product of electrolytic copper refining, refining of native silver, gold, nickel and zinc, and by application of the Parkes process to metallic lead, which is derived from lead ores containing small amounts of silver. Commercial grade fine silver has a minimum purity of 99.9% and purities greater than 99.999% are available. In 2011, Mexico was the top silver producer (4,500 tons or 19% of the world total), closely followed by Peru (4,000 tons) and China (4,000 tons).[41]

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At $19.53 per troy ounce on July 19, 2013[42], silver is about 1/66th the price of gold. The ratio has changed from 1/15 to 1/100 in the last 100 years. [citation needed] Physical silver bullion prices are higher than paper prices and premiums rise when demand is high and there is a local shortage. [43] In 1980 the price of silver rose to a modern high of $49.45 per troy ounce (ozt) due to market manipulation by Nelson Bunker Hunt and Herbert Hunt. Silver Price History 1960-2011 Adjusted for inflation in 2012, this is approximately $138 per troy ounce. Sometime after Silver Thursday, the price returned to $10/oz.[44] From 2001 to 2010 the price increased from $4.37 to $20.19 (average of $/ounce in London). [ ] In late April 2011, silver hit an all-time high of $49.76/ozt. Silver fetched much higher prices in earlier times. In the early 15th century, silver was estimated to have been priced at over $1,200 an ounce based on 2011 dollars.[45] It has been pointed out that the discovery of vast deposits of silver in the New World led to a significant fall in its price over the following centuries. The price of silver is important in Jewish law. The lowest amount of tax a Jewish court or Beth Din can ask to adjudicate a case is one Pruta Shova (value of one Babylonian Pruta coin). [citation needed] This is defined as 0.025 grams (0.00088 ounces) of pure unrefined silver at market price. In a Jewish tradition that continues to this day, on the first birthday of an eldest son, parents pay a kohen (priest) the price of five pieces of pure silver. Today, the Mint of Israel sets coins at 117 grams (4.1 ounces) of silver. The kohen usually give these silver coins back to the child as a gift for them to inherit.[46]

Human exposure and consumption Silver has no known natural biological role in humans, and the potential health effects of silver are controversial. Silver itself is not toxic to humans, but most silver salts are. In large doses, silver and silver-containing compounds can be absorbed into the circulatory system and deposited in various body tissues, causing argyria, resulting in a blue-gray discoloration of the skin, eyes, and mucous membranes. Argyria is rare, and while this condition is not known to affect a person's health, it is disfiguring and usually permanent. Mild forms of argyria are sometimes confused with cyanosis.[3]

Exposure controls Excessive exposure to silver can occur in workers in the metal fabricating industry, those taking dietary supplements containing silver, patients being treated with silver sulfadiazine, and those accidentally or intentionally ingesting silver salts. Silver concentrations in whole blood, plasma, serum, or urine can be measured to monitor the safety of exposed workers, to confirm the diagnosis in potential poisoning victims, or to aid in forensic investigation in the event of a fatal overdose.[47]

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Food use Silver is used in food coloring; It bears the designation E174 and is approved in the European Union. The safety of silver for food use has been questioned. [] Traditional Indian dishes sometimes involve the use of decorative silver foil known as vark, [] and in various cultures silver dragees are used to decorate cakes, biscuits and other desserts. [ ] Silver is not approved as a food additive in the United States. [citation required]

References [1] Magnetic Susceptibility of Elements and Inorganic Compounds (http://www-d0.fnal.gov/hardware/cal/lvps_info/engineering/elementmagn.pdf) in [14] Law of Utah makes coins worth their weight in gold (or silver) (https://www.nytimes.com/2011/05/30/us/30gold.html), New York Times, May 29, 2011 [19] Hill, Russ (1999). Applications and markets for coated glass. Fairfield, CA: BOC Coating Technology. pp. 1 to 4. ISBN 0-914289-01-2. [25] Oliver, C. (1994) Use of Immunogold with Silver Enhancement Methods in Molecular Biology. 34, 211-216. doi=10.1385/0-89603285-X:211 [26] Beattie, M.; Taylor, J (August 2011). "Silver alloy versus uncoated urinary catheters: a systematic review of the literature". Journal of Clinical Nursing 20(15–16): 2098–108. doi:10.1111/j.1365-2702.2010.03561.x. PMID 21418360. name=Bou2012> [31] Nanofabric washing: Can nanosilver escape from clothing? (http://ec.europa.eu/environment/integration/research/newsalert/pdf/178na5.pdf), European Commission, 17 December 2009 [34] T. Amemiya (p. 7) Economics and Economics of Ancient Greece (http : / / books. google. co. uk/ books?id=DcTj4AUFemAC& printsec=frontcover& dq=ancient+ history+ of+ Foreign+ Exchange& hl=en#v=onepage& q=old exchange history& f=false) Taylor & Francis, 2007 Access 2012 - 01-18 [36] White, Matthew The Great Big Book of Horrible Things" New York: 2012 W.W. Norton "The Opium War" pages 285-286 [41] Silver Statistics and Information (http://minerals.usgs. gov/ minerals/ pubs/ commodities/ silver/ ), USGS [42] Retrieved 2013-07-20 (http://www.kitcosilver.com/ ) [43] Precious metal premiums will exceed spot price - International Business Times (http://www .ibtimes.com/articles/342907/20120518/will-precious-metal-premiums-one-day-trump.htm).ibtimes.com (2012-05-18), retrieved on 2012-05-28 [45 ] Live Silver prices, Prices of millions of silver and 650 years of syllable rpreise (http://goldinfo. Network / Silver 600. html). goldinfo.net. Retrieved 2011-05-02. [46] Judaism Alive: The Complete Guide to Jewish Beliefs and Traditions, Wayne D. Dosick – 1995 “The price was fixed at five shekalim (plural of shekel, the currency of the time) for each of the 273 firstborn (numbers 3: 47) that Money was given to Aaron the high priest, chief of the tribe of Levi.” [47] Baselt, R. Disposition of Toxic Drugs and Chemicals in Man, 8th edition, Biomedical Publications, Foster City, CA, 2008, ISBN 0-9626523 -7-7 pp. 1429–1431.

External Links • Chemistry in Your Element Podcast (http://www.rsc.org/chemistryworld/podcast/element.asp) (MP3) from Chemistry World of the Royal Society of Chemistry: Silver (http://www.rsc .org ) /images/ CIIE_silver_48kbps_tcm18-118748.mp3) • Silver (http://www.periodicvideos.com/videos/047.htm) in the Periodic Table of Videos (University of Nottingham) • Society of American Silversmiths (http:// www.silversmithing.com/) • The Silver Institute (http://www.silverinstitute.org/) A silver industry website • A collection of silverware (http://www.theodoregray.com/PeriodicTable/Elements/047/index . html) Silver samples • Transportation, fate and environmental impact of silver (http://digital.library.wisc.edu/1711.dl/EcoNatRes. Argentum) • CDC – NIOSH Pocket Guide to Chemical Hazards – Silver ( http: //www.cdc.gov/niosh/npg/npgd0557.html) • Image from Heinrich Pniok's Element Collection (http://www.pniok.de/ag.htm)

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copper

110

copper copper with 29

Nickel ← Copper → Zinc ↑

Cu ↓ Ag Copper in the periodic table Appearance Red-orange metallic luster

Native copper (approx. 4 cm in size) General characteristics Name, symbol, number

includes with 29

pronunciation

/ˈkɒpər/ COP

item category

transition metal

group, period, block

11, 4, diam

standard atomic weight

63.546(3)

copper

111 Electronic configuration

[Ar] 3d10 4s1 2, 8, 18, 1

story name

to Cyprus, most important mining site in Roman times (Cyprus)

discovery

Middle East (9000 BC) Physical Properties

Phase

fest

Density (near room temperature)

8,96 g·cm−3

Density of the liquid in m.p.

8,02 g·cm−3

fusion point

1357,77 K, 1084,62 °C, 1984,32 °F

boiling point

2835K, 2562°C, 4643°F

heat of fusion

13.26 kJ·mol-1

heat of vaporization

300.4 kJ·mol−1

molar heat capacity

24,440 J mol-1 K-1 vapor pressure

P (Pa)

100

1 k

10 thousand 100 thousand

in T (K) 1509 1661 1850 2089 2404 2834 Atomic Properties Oxidation States

+1, +2, +3, +4 (slightly basic oxide)

electronegativity

1.90 (Pauling scale)

Ionization energies (more)

1°: 745.5 kJ·mol−1 2°: 1957.9 kJ·mol−1 3°: 3555 kJ·mol−1

Atomic func

128 S. m.

covalent ray

132±16h

Radio Van der Waals

140 hours of miscellaneous

copper

112 crystal structure

face-centered cubic

magnetic request

diamagnetic

Electrical resistance

(20°C) 16,78 nΩ·m

thermal conductivity

401W·m−1·K−1

thermal expansion

(25 °C) 16,5 µm·m−1·K−1

[1]

Speed of sound (thin bar) (r.t.) (annealed) 3810m s−1 Modulus of elasticity

110–128 GPa

Schneidmodul

48 GPa

Volumenmodul

140 GPa

poison ratio

0,34

Mohs hardness

3.0

Dureza Vickers

369 MPa

Brinell hardness

35 HB = 874 MPa

CAS registration number

7440-50-8 More stable isotopes Main article: Copper isotopes

You are so

THE

covers 69.15%

63 64

copper

sin

covers 30.85%

65 67

copper

sin

Half-life DM SD (MeV) SD 63

Cu is stable with 34 neutrons.

12,700 hours

b−

Zink

Sixty-five

Cu is stable with 36 neutrons

61.83 hours

b−

Zink

Copper is a chemical element with the symbol Cu (from Latin: cuprum) and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; a newly exposed surface is reddish-orange in color. It is used as a conductor of heat and electricity, a building material and a component of various metal alloys. The metal and its alloys have been used for thousands of years. In Roman times, copper was mainly mined on Cyprus, hence the metal's name as сyprium (Cyprus metal), later shortened to сuprum. Its compounds are commonly found as copper(II) salts, which often impart blue or green colors to minerals such as azurite and turquoise, and historically have been widely used as pigments. Architectural structures built with copper will corrode and develop verdigris (or patina). Decorative arts highlight copper, both alone and as part of pigments. Copper is essential as a dietary trace element for all living organisms as it is a key component of the cytochrome c oxidase respiratory enzyme complex. In mollusks and crustaceans, copper is a component of the blood pigment hemocyanin, which is replaced by the iron complex hemoglobin in fish and other vertebrates. The most important areas

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Where copper is found in humans is the liver, muscles, and bones.[2] Copper compounds are used as bacteriostatic substances, fungicides and wood preservatives.

Physical Properties

A copper disc (99.95% pure) made by continuous casting and etching.

Copper, just above its melting point, retains its light pink color when enough light dulls the bright orange color.

Belonging to group 11 of the periodic table, copper, silver and gold share some properties in common: they have an s orbital electron on a shell filled with d electrons and are characterized by high ductility and electrical conductivity. The filled d shells of these elements do not contribute much to interatomic interactions, which are dominated by s electrons through metallic bonds. Unlike metals with incomplete d shells, metallic bonds in copper are not covalent in character and are relatively weak. This explains the low hardness and high ductility of copper single crystals. [] At the macroscopic level, the introduction of extensive defects into the crystal lattice, such as B. grain boundaries, the flow of the material under applied stress, which increases its hardness. For this reason, copper is commonly supplied in a fine-grained polycrystalline form, which has greater strength than monocrystalline forms.[3] The softness of copper partly explains its high electrical conductivity (59.6 × 106 S/m) and hence its high thermal conductivity, which is the second highest among pure metals at room temperature.[3] This is because the resistance to electron transport in metals at room temperature is mainly caused by the scattering of electrons in the thermal modes of the lattice, which are relatively weak for a soft metal. [ ] The maximum allowable current density of copper outdoors is about 3.1 × 106 A/m2 cross-sectional area, above that it starts to get excessively hot.[4] As with other metals, galvanic corrosion occurs when copper is placed against another metal.[5]

Along with cesium and gold (both yellow) and osmium (blue), copper is one of four elemental metals with a natural color other than gray or silver.[6] Pure copper is reddish-orange in color and becomes reddish in air. The characteristic color of copper results from electronic transitions between the filled 3d and semi-empty 4s atomic layers; the energy difference between these layers is so great that it corresponds to orange light. The same mechanism explains the yellow color of gold and cesium.[]

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Chemical

Unoxidized copper wire (left) and oxidized copper wire (right).

Copper forms a variety of compounds in the +1 and +2 oxidation states, often referred to as copper(I) and copper(II), respectively.[93] It does not react with water, but slowly reacts with atmospheric oxygen to form a dark brown copper oxide layer. In contrast to the oxidation of iron by moist air, this oxide layer stops massive corrosion. A green coating of verdigris (copper carbonate) is often seen on older copper structures such as the Statue of Liberty, the largest copper statue in the world, built with scraps and chisels.[7] Copper darkens when exposed to hydrogen sulfide and other sulfides, which react with it to form various copper sulfides on the surface.[8] Oxygenated solutions of ammonia form water-soluble complexes with copper and oxygen and hydrochloric acid to form copper chlorides and acidified hydrogen peroxide to form copper(II) salts. Copper(II) chloride and copper content to form copper(I) chloride.[9]

Isotope

The east tower of the Royal Observatory in Edinburgh. The contrast between the refurbished copper installed in 2010 and the green color of the original 1894 copper can clearly be seen.

There are 29 copper isotopes. 63Cu and 65Cu are stable, with 63Cu comprising about 69% native copper; both have spin 3/2.[] The other isotopes are radioactive, the most stable being 67Cu with a half-life of 61.83 hours.[] Seven metastable isotopes have been characterized, with 68mCu being the longest-lived with a half-life of 3.8 minutes . Isotopes with a mass number greater than 64 decay to β-, while those with a mass number less than 64 decay to β+. 64Cu, which has a half-life of 12.7 hours,

decays in both directions.[10] 62

Cu and 64Cu have important applications. 64Cu is an X-ray contrast agent for X-ray imaging and can be used in complex with a chelate to treat cancer. 62Cu is used in 62Cu-PTSM, a radioactive tracer for positron emission tomography.[11]

Occurrence Copper is synthesized in massive stars[12] and is present in the Earth's crust at a concentration of approximately 50 parts per million (ppm)[] where it occurs as native copper or in minerals such as chalcopyrite and chalcocite copper sulfides, carbonates, and azurite - and malachite copper and the copper(I) oxide mineral cuprite.[3] The largest mass of elemental copper ever discovered weighed 420 tons and was found in 1857 on the Keweenaw Peninsula in Michigan, USA. [] Native copper is a polycrystal, with the largest single crystal described measuring 4.4 × 3.2 × 3.2 cm. [13]

Copper native to the Keweenaw Peninsula, Michigan, about 2.5 inches (6.4 cm) long

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Production

Chuquicamata in Chile is one of the largest open pit copper mines in the world.

Most copper is mined or mined as copper sulphide in large open pit mines in porphyry copper deposits at 0.4 to 1.0% copper. Examples are Chuquicamata in Chile, the Bingham Canyon mine in Utah, USA, and the El Chino mine in New Mexico, USA. According to the British Geological Survey, Chile was the leading producer of copper mines in 2005 with at least a third of the world share, followed by the United States, Indonesia and Peru.[3] Copper can also be recovered by the in situ leach process. Several locations in the state of Arizona are considered prime candidates for this method.[14] The amount of copper used is increasing and the amount available is barely sufficient to allow all countries to match the consumption levels of the developed world.[15]

reservations

Copper production in 2005

Copper has been used for at least 10,000 years, but over 96% of all mined and smelted copper has been mined since 1900, with over half being mined in the last 24 years alone. As with many natural resources, the total amount of copper on earth is enormous (about 1,014 tons in the top kilometer of the earth's crust alone, or about 5 million years at current mining rates). However, only a small fraction of these reserves are commercially viable given current prices and technology. Various estimates of existing copper reserves available for mining range from 25 to 60 years depending on basic assumptions such as growth rate.[16] Recycling is an important source of copper in the modern world. [] Because of these and other factors, the future of copper production and supply is the subject of much debate, including the concept of peak copper, analogous to peak oil.

Copper prices 2003-2011 in USD per ton

Historically, the price of copper has been volatile[17], rising from a 60-year low of $0.60/lb ($1.32/kg) in June 1999 to $3.75/lb.lb (8.27 $/kg) in May 2006 fell fivefold in February 2007 to US$2.40/lb (US$5.29/kg) and then recovered to US$3.50/lb in April 2007 ( $7.71/kg).[18] In February 2009, weaker global demand and a sharp drop in commodity prices from last year's highs left the copper price at $1.51/lb.[19]

world production trend

Methods The average concentration of copper in ores is only 0.6%, and most commercial ores are sulphides, particularly chalcopyrite (CuFeS2) and to a lesser extent chalcocite (Cu2S).[] These ores are concentrated from copper ores ground to a grade of 10– 15% copper by froth flotation or bioleaching.[20] Heating this material with silica during rapid casting removes much of the iron as slag. The process takes advantage of the facile conversion of iron sulfides into their oxides, which in turn react with the silica to form siliceous slag that floats on the heated mass. The resulting copper matte, composed of Cu2S, is roasted to convert all sulfides into oxides: [] 2 Cu2S + 3 O2 → 2 Cu2O + 2 SO2

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116

Copper oxide turns into bubbly copper when heated: 2 Cu2O → 4 Cu + O2 Sudbury's frosting process converted only half of the sulfide to oxide and then used that oxide to remove the rest of the sulfur as oxide. It was then electrolytically refined and the anode slurry extracted for the platinum and gold contained. This step takes advantage of the relatively easy reduction of copper oxides to metallic copper. Natural gas is bubbled through the flask to remove most of the remaining oxygen, and the resulting material is electrorefined to produce pure copper:[21] Cu2+ + 2 e– → Cu

Recycling Copper, like aluminium, is 100% recyclable with no loss of quality, whether in the raw state or in an industrial product. Copper is the third most recycled metal by volume, after iron and aluminum. An estimated 80% of all copper ever mined is still in use today.[22] According to the International Resource Panel report “Metal Stocks in Society”, the world per capita stock of copper used in society is 35 to 55 kg. Much of this is more likely to occur in more developed countries (140–300 kg per capita) than in less developed countries (30–40 kg per capita). The copper recycling process follows roughly the same steps used to extract copper, but requires fewer steps. High-purity copper scrap is melted down in a furnace and then crushed and formed into billets and ingots; Scrap of lower purity is refined by electroplating in a sulfuric acid bath.[23]

Alloys There are numerous copper alloys, many of which have important uses. Brass is an alloy of copper and zinc. Bronze usually refers to copper and tin alloys but can refer to any copper alloy such as bronze and aluminum. Copper is one of the key ingredients in karat silver and gold alloys and karat solders used in the jewelry industry, and modifies the color, hardness, and melting point of the resulting alloys. [ ] The alloy made of copper and nickel, called copper-nickel, is used. often for the outer coating of small change coins. US nickel coins are 75% copper and 25% nickel and have a homogeneous composition. The 90% copper/10% nickel alloy is characterized by its corrosion resistance and is used in various parts that are exposed to sea water. Copper-aluminum alloys (about 7%) have a pleasing golden color and are used for decoration.[] Some lead-free solders are made from an alloy of tin with small amounts of copper and other metals.[24]

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Connections Binary Connections As with the other elements, the simplest copper connections are binary connections, ie those consisting of only two elements. The most important are oxides, sulfides and halides. Both copper(I) and copper(II) oxides are known. Among the numerous copper sulfides, copper(I) sulfide and copper(II) sulfide are important examples. Known are copper halides with chlorine, bromine and iodine and copper halides with fluorine, chlorine and bromine. Attempts to prepare copper(II) iodide yield copper(I) iodide and iodine.[93] 2 Cu2+ + 4 I− → 2 CuI + I2

A sample of cuprous oxide.

Coordination chemistry Like all metals, copper forms coordination complexes with ligands. In aqueous solution, copper(II) is present as [Cu(H2O)6]2+. This complex shows the fastest rate of water exchange (rate of binding and separation of water ligands) of any aqueous transition metal complex. Addition of aqueous sodium hydroxide causes precipitation of a light blue solid cupric hydroxide. A simplified equation is: Cu2+ + 2 OH− → Cu(OH)2 Aqueous ammonia gives the same precipitate. With the addition of excess ammonia, the precipitate dissolves, forming tetraaminocopper(II):

Copper(II) gives a deep blue color in the presence of ammonia ligands. The one used here is tetraamino copper(II) sulfate.

Cu(H2O)4(OH)2 + 4 NH3 → [Cu(H2O)2(NH3)4]2+ + 2 H2O + 2 OH−

Many other oxyanions form complexes; these include copper(II) acetate, copper(II) nitrate and copper(II) carbonate. Copper(II) sulfate forms a blue crystalline pentahydrate, which is the most familiar copper compound in the laboratory. It is used in a fungicide called Bordeaux broth.[]

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Polyols, compounds containing more than one alcoholic functional group, generally interact with copper salts. For example, copper salts are used to test reducing sugars. In particular, when using Benedikt's reagent and Fehling's solution, the presence of sugar is indicated by a color change from blue Cu(II) to reddish copper(I) oxide.[25] Schweizer's reagent and related complexes with ethylenediamine and other amines dissolve cellulose.[26] Amino acids form very stable chelate complexes with copper(II). There are many wet chemical tests for copper ions, one using potassium ferrocyanide which gives a brown precipitate with copper(II) salts.

Organokupferchemie

Ball-and-stick model of the [Cu(NH3)4(H2O)2]2+ complex illustrating the common octahedral coordination geometry for copper(II).

Compounds that contain a carbon-copper bond are referred to as organocopper compounds. They are highly reactive with oxygen to form cuprous oxide and have many uses in chemistry. They are synthesized by treating copper(I) compounds with Grignard reagents, terminal alkynes, or organolithium reagents;[27] in particular, the latter reaction generates a Gilman reagent. These can be substituted with alkyl halides to form coupling products; as such they are important in the field of organic synthesis. Copper(I) acetylide is very shock sensitive, but is an intermediate in reactions such as the Cadiot-Chodkiewicz coupling [28] and the Sonogashira coupling. [29] The addition of conjugates to enones[30] and the carbocupration of alkynes[31] are also possible with organocopper compounds. Copper(I) forms a variety of weak complexes with alkenes and carbon monoxide, particularly in the presence of amine ligands.[32]

Copper(III) and Copper(IV) Copper(III) occurs most characteristically in oxides. A simple example is potassium cuprate, KCuO2, a dark blue solid. The best-studied copper(III) compounds are the cuprate superconductors. Yttrium barium copper oxide (YBa2Cu3O7) consists of Cu(II) and Cu(III) centers. Like the oxide, fluorine is a strongly basic anion and is known to stabilize metal ions in high oxidation states. In fact, copper(III) and even copper(IV) fluorides, K3CuF6 and Cs2CuF6, respectively, are known.[93] Some copper proteins form oxo complexes that also contain copper(III).[33] In the case of di- and tripeptides, violet copper(III) complexes are stabilized by deprotonated amide ligands.[34] Copper(III) complexes are also observed as intermediates in reactions of organocopper compounds.

copper

Copper Age History Copper occurs naturally as native copper and was known to some of the earliest recorded civilizations. It has a history of use of at least 10,000 years, with estimates of its discovery as early as 9,000 BC. C. Middle East; [ ] A copper pendant dating from 8700 BC was discovered in northern Iraq. found. C. [35] There is evidence that gold and meteoric iron (but not cast iron) were the only metals used by humans, before copper. [] The history of copper metallurgy is believed to have followed the following sequence: 1) native cold-work copper, 2) an eroded copper ingot from Zakros, Crete, annealed, 3) smelting, and 4) the lost-wax process. In the form of the southeast in the form of a typical Anatolian animal skin, these four metallurgical techniques appear in this period. at least simultaneously in the early Neolithic c. 7500 BC C. [] Just as agriculture was invented independently in different parts of the world (including Pakistan, China, and America), so copper smelting was invented locally in many different places. It was probably made before 2800 BC. Independently discovered in China. C., in Central America perhaps around 600 AD C. and in West Africa around 9th or 10th century AD C. [36] Investment casting was practiced between 4500 and 4000 BC. invented. in Southeast Asia[] and carbon dating has placed mining at Alderley Edge in Cheshire, UK, between 2280 and 1890 BC. C. [37] Ötzi the Iceman, a man from the years 3300–3200 BC. C., was found with an ax Mineral copper (chrysocolla) in Cambrian sandstone with a copper head with a purity of 99.7%; high levels of arsenic in your hair from copper mines in the Timna Valley of southern Israel. indicate his participation in the copper smelter. [] Experience with copper helped develop other metals; the smelting of copper in particular led to the discovery of the smelting of iron. [] Production at the Old Copper Complex in Michigan and Wisconsin dates from 6000 to 3000 BC. Natural bronze, a type of copper from ores rich in silicon, arsenic and (rarely) tin, became widespread around 5500 BC. in the Balkans.

Bronze Age Alloying of copper with tin to produce bronze was first practiced some 4,000 years after the discovery of copper smelting and some 2,000 years after "natural bronze" became widespread. Bronze artifacts from Sumerian cities and Egyptian artifacts made from copper and bronze alloys date back to 3000 BC. C. [] The Bronze Age began in Southeastern Europe around 3700-3300 BC. C., in northwestern Europe around 2500 BC. It ended with the beginning of the Iron Age, 2000-1000 BC. C. Near East, 600 AD in Northern Europe. The transition between the Neolithic and the Bronze Age was formerly called the Chalcolithic (Copperstone Age), using copper tools with stone tools. This term has gradually fallen out of use as the Chalcolithic and Neolithic meet at both extremes in some parts of the world. Brass, an alloy of copper and zinc, is of much more recent origin. It was known to the Greeks but became an important complement to bronze during the Roman Empire.[]

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Antiquity and the Middle Ages

In alchemy, the copper symbol was also the symbol of the goddess and the planet Venus.

In Greece, copper was known under the name Chalkos (χαλκός). It was an important resource for the Romans, Greeks and other ancient peoples. In Roman times it was known as aes cyprium, aes being the Latin generic term for copper alloys, and cyprium from Cyprus, where much copper was mined. The term was simplified to cuprum, hence the English copper. Aphrodite and Venus represented copper in mythology and alchemy due to its radiant beauty, its ancient use in making mirrors, and its association with Cyprus, sacred to the goddess. The seven celestial bodies known to the ancients were associated with the seven known ancient metals, and Venus was attributed to copper.[40] Brass was first used in Britain around the 3rd century BC. In North America, copper mining began with menial labor by Native Americans. Native copper is known to have been mined at Isle Royale sites between 800 and 1600 using primitive stone tools. [41] Copper metallurgy flourished in South America, particularly Peru, around AD 1000. On other continents, progress was much slower. Copper funerary decorations from the 15th century were discovered, but commercial production of the metal did not begin until the early 20th century.

Chalcolithic copper mine in Timna Vale, Negev desert, Israel.

The cultural role of copper was important, especially in relation to currencies. The Romans between the 6th and 3rd centuries B.C. C. used copper pieces as money. Initially, copper itself was valued, but gradually the shape and appearance of copper became important. Julius Caesar had his own coins made out of brass, while Octavian Augustus Caesar's coins were made out of Cu-Pb-Sn alloys. With an estimated annual production of around 15,000 t, Roman copper mining and smelting activities reached unprecedented levels by the time of the Industrial Revolution; the most mined provinces were Hispania, Cyprus and Central Europe.[42][43] The doors of the Temple of Jerusalem used Corinthian bronze made by exhaust gilding. It was most widespread in Alexandria, where alchemy is thought to have begun.[44] In ancient India, copper was used in the holistic medical science of Ayurveda for surgical instruments and other medical devices. The ancient Egyptians (circa 2400 BC) used copper to sterilize wounds and drink water, and later for headaches, burns and itching. The Baghdad Battery, with copper cylinders soldered with lead, dates from 248 BC. C. to 226 d. C. and resembles a galvanic cell, leading people to believe that this was the first battery; the claim has not been verified.[45]

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Modern times The Great Copper Mine was a mine in Falun, Sweden that operated from the 10th century to 1992. It produced two-thirds of Europe's copper needs in the 17th century and helped finance many of Sweden's wars during the period.46 It was known as the nation's treasure; Sweden had a copper-backed currency.[47] The use of copper in art was not limited to coinage: it was used by Renaissance sculptors, in the photographic technology known as daguerreotype, and on the Statue of Liberty. Copper plating and copper plating of ships' hulls were common; Christopher Columbus' ships were among the first to have this feature.[48] The Norddeutsche Affinerie in Hamburg was the first modern electroplating shop to start production in 1876.[49] German scientist Gottfried Osann invented powder metallurgy in 1830 when he determined the atomic mass of metal; It was then discovered that the amount and type of alloying element (e.g. tin) to copper would affect the tones of bells. Flash Casting was developed by Outokumpu in Finland and first applied in Harjavalta in 1949; The energy-efficient process accounts for 50% of global primary copper production.[50]

Acid mine drainage affecting the creek leaving the disused Parys Mountain copper mines

The Intergovernmental Council of Copper Exporting Countries, formed in 1967 with Chile, Peru, Zaire and Zambia, played a role for copper similar to that played by OPEC for oil. It never achieved the same influence, mainly because the second largest producer, the United States, was never a member; Disbanded in 1988.[51]

Applications The main uses of copper are electrical wiring (60%), roofing and plumbing (20%) and industrial machinery (15%). Copper is mostly used as a pure metal, but when higher hardness is required it is combined with other elements to make an alloy (5% of total usage) such as brass and bronze. [] A small portion of the copper supply is used to make compounds for agricultural nutritional supplements and fungicides. [][] Machining of copper is possible, although it is often necessary to use an alloy for intricate parts to achieve a maintain good machinability properties.

various copper accessories

Wire and Cable Despite competition from other materials, copper remains the preferred electrical conductor in almost every category of electrical wiring, with the major exception in overhead wire, where aluminum is often preferred. [52][53] ] Copper wire is used in power generation, power transmission, power distribution, telecommunications, electronic circuits, and numerous types of electrical appliances.[54] Electrical wiring is the most important market for the copper industry.[55] These include construction cables, communication cables, power distribution cables, appliance cables, automotive cables and wires, and magnetic cables. About half of all copper mined is used to make electrical wire and cable conductors.[56] Many electrical devices rely on copper wiring for its host of inherent beneficial properties such as high electrical conductivity, tensile strength, ductility, creep (strain) resistance, corrosion resistance, low thermal expansion, high thermal conductivity, solderability,

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and easy installation.

Electronic and related devices Integrated circuits and printed circuit boards are increasingly using copper instead of aluminum due to its superior electrical conductivity (see main article under copper interconnects); Heat sinks and heat exchangers use copper due to its superior heat dissipation ability over aluminum. Electromagnets, vacuum tubes, cathode ray tubes, and microwave magnetrons use copper, as do waveguides for microwave radiation.[57]

Electric motors The higher conductivity of copper compared to other metallic materials improves the electric power efficiency of motors.[58] This is important as motors and engine-driven systems account for 43-46% of all electricity consumption worldwide and 69% of all industry electricity consumption.[59] Increasing the mass and cross-section of copper in a coil increases the electrical power efficiency of the motor. A new large-scale design technology developed for motor applications where energy savings[60][61] are the primary design goals, copper motor rotors enable general-purpose induction motors to meet and exceed industry standards. National Electrical Manufacturers Association (NEMA) premium efficiency rating.[62]

Architecture Copper has been used since ancient times as a durable, corrosion and weather resistant architectural material.[63][64][65][66] Roofs, sheet metal, downspouts, gutters, domes, battlements, vaults, and doors have been made of copper for hundreds or thousands of years. Architectural uses of copper in modern times have expanded to include interior and exterior wall cladding, building expansion joints, radio frequency shielding, and interior antimicrobial products such as attractive handrails, bathroom fixtures, and countertops. Other important advantages of copper as a building material include its low thermal movement, light weight, lightning protection, and recyclability.

Patinated copper ceiling at Minneapolis City Hall

The metal's distinctive natural green patina has long been coveted by architects and designers. The final patina is a particularly durable layer that is highly resistant to atmospheric corrosion, thereby protecting the underlying metal from further deterioration.[67][68][69] It can be a mixture of carbonate and sulphate compounds in varying amounts depending on environmental conditions such as: sulphurous acid rain.[70][71][72][73][74] Architectural copper and its alloys can also be "refined" to obtain a specific look, feel and/or color. Surface treatments include mechanical surface treatments, chemical coloring, and coatings.[75]

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Copper has excellent brazing and soldering properties and can be soldered; The best results are achieved with gas metal arc welding.[76]

Antifouling Applications Copper has long been used as a biostatic surface to coat marine components to protect against barnacles and mussels. It was originally used properly but has since been replaced by Muntz metal. Bacteria will not grow on a copper surface as it is biostatic. Likewise, as discussed under Copper alloys in aquaculture, copper alloys have become important netting materials in the aquaculture industry due to the fact that they are antimicrobial and prevent biofouling even under extreme conditions. [77] and have strong structural and corrosion resistant [78] properties in marine environments.

Old copper utensils in a restaurant in Jerusalem

Antimicrobial Uses Numerous antimicrobial efficacy studies have been conducted over the last 10 years on the effectiveness of copper in killing a variety of bacteria, as well as influenza A viruses, adenoviruses, and fungi.[79] Copper alloy contact surfaces have intrinsic natural properties to kill a variety of microorganisms (e.g. E. coli O157:H7, methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus, Clostridium difficile, influenza A virus, adenovirus and fungi). [79] Some 355 copper alloys have been shown to kill over 99.9% of disease-causing bacteria in just two hours when regularly cleaned.[80] The U.S. Environmental Protection Agency (EPA) has approved registrations for these copper alloys as “antimicrobial materials with public health benefits”[80], allowing manufacturers to make legal claims about the positive public health benefits of products made from registered antimicrobial materials materials are made. Copper Alloys In addition, the EPA has approved a long list of antimicrobial copper products made from these alloys, including railings, handrails, nightstands, sinks, faucets, doorknobs, plumbing fixtures, computer keyboards, gymnasium, shopping cart handles, and more. Plumbing systems.[81] Copper alloy antimicrobial products are installed in healthcare facilities in the UK, Ireland, Japan, Korea, France, Denmark and Brazil. l and the underground transportation system in Santiago, Chile, where copper-zinc alloy handrails will be installed at about 30 stations between 2011 and 2014.[82][83][84]

Other uses Copper compounds in liquid form are used as a wood preservative, particularly in the treatment of original components when cleaning up dry rot damage. Along with zinc, copper wire can be placed over non-conductive roofing materials to discourage moss growth. Textile fibers use copper to make antimicrobial protectants,[85] as do ceramic glazes, stained glass, and musical instruments. In electroplating, copper is often used as a base for other metals such as nickel. Along with lead and silver, copper is one of three metals used in a museum materials testing procedure called the Oddy test. In this method, copper is used to detect chlorides, oxides and sulfur compounds.

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Copper is commonly used in jewelry, and folklore has it that copper bracelets relieve symptoms of arthritis.[86] Copper is the main alloying metal in silver and gold alloys. It can also be used alone or as a component of brass, bronze, gold metal and many other base metal alloys. Copper is used as a printing plate in engraving, etching, and other forms of intaglio engraving. Copper oxide and carbonate are used in the manufacture of glass and ceramic glazes to impart green and brown colors.

Biological Role Copper proteins play diverse roles in the biological transport of electrons and oxygen, processes that take advantage of the facile interconversion of Cu(I) and Cu(II).[87] [88] [89] The biological role of copper began with the appearance of oxygen in the Earth's atmosphere.[90] The protein hemocyanin is the oxygen carrier in most molluscs and some arthropods, such as the horseshoe crab (Limulus polyphemus). Because hemocyanin is blue, these organisms have blue blood, not the red blood found in organisms that rely on hemoglobin for this purpose. . Structurally related to hemocyanin are laccases and tyrosinases. Instead of reversibly binding oxygen, these proteins hydroxylate substrates, as demonstrated by their role in varnish formation.[89]

Rich sources of copper are oysters, beef and lamb liver, Brazil nuts, molasses, cocoa and black pepper. Good sources include lobster, nuts and sunflower seeds, green olives, avocados, and wheat bran.

Copper is also a component of other proteins related to oxygen processing. In cytochrome c oxidase, which is necessary for aerobic respiration, copper and iron work together to reduce oxygen. Copper is also found in many superoxide dismutases, proteins that catalyze the breakdown of superoxides and convert them (through disproportionation) to oxygen and hydrogen peroxide: 2 HO2 → H2O2 + O2 Various copper proteins, such as B. "blue copper proteins", do not interact directly with substrates, so are not enzymes. These proteins pass electrons through a process called electron transfer.[89]

Nutritional requirements Copper is an essential trace element in plants and animals, but not in some microorganisms. The human body contains copper in an amount of about 1.4 to 2.1 mg per kg of body weight. [ ] In other words, the RDA for copper in normal healthy adults is 0.97 mg/day and 3.0 mg/day.[91] Copper is absorbed in the gut and then bound to albumin and transported to the liver.[92] After processing in photosynthesis, it acts through an elaborate electron transport chain within the thylakoid membrane. A central "link" in this chain is plastocyanin, a blue copper protein. Liver, copper is distributed to other tissues in a second phase. Copper transport involves the protein ceruloplasmin, which transports most of the copper in the blood. Ceruloplasmin also transports copper, which is excreted in milk and is particularly well absorbed as a source of copper.[93] copper in the body

(Video) Difference between Welding, Brazing, and Soldering.

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is normally subject to enterohepatic circulation (about 5 mg per day versus about 1 mg per day ingested with food and eliminated from the body), and the body can excrete some excess copper as needed via the bile, which carries some copper out of the Body. the liver, which is then not resorbed by the intestine.[94][95]

Copper-Based Disorders Because of its role in facilitating iron absorption, copper deficiency can produce related symptoms such as anemia, neutropenia, bone abnormalities, hypopigmentation, growth failure, increased incidence of infections, osteoporosis, hyperthyroidism, and abnormalities in copper metabolism, glucose, and cholesterol. In contrast, Wilson's disease causes accumulation of copper in body tissues. Severe deficiency can be detected by testing for low levels of plasma or serum copper, low levels of ceruloplasmin, and low levels of superoxide dismutase in red blood cells; these are insensitive to the edge state of copper. "Leukocyte and platelet cytochrome C oxidase activity" was reported as another deficiency factor, but the results were not confirmed by replication.[] NFPA 704

Fire diamond for copper metal

Gram amounts of various copper salts have been ingested in suicide attempts and have resulted in acute copper toxicity in humans, possibly due to the redox cycle and the formation of DNA-damaging reactive oxygen species.[96] Equivalent amounts of copper salts (30 mg/kg) are toxic to animals.[97] It has been reported that a minimum dietary level for healthy growth in rabbits is at least 3 ppm in the diet.[98] However, higher concentrations of copper (100 ppm, 200 ppm, or 500 ppm) in rabbit chow can favorably affect feed conversion efficiency, growth rates, and percentage of carcass cleaning.[99] Chronic copper toxicity does not normally occur in humans because transport systems regulate uptake and excretion. Autosomal recessive mutations in copper transport proteins can disable these systems, resulting in Wilson's disease with copper accumulation and liver cirrhosis in people who have inherited two defective genes.[]

References [1] Magnetic Susceptibility of Elements and Inorganic Compounds (http://www-d0.fnal.gov/hardware/cal/lvps_info/engineering/elementmagn.pdf) in [14] http://www. azcentral. com/arizonarepublic/business/articles/2011/06/19/20110619 cover-new-method-fight. html [23] "Recycled Copper Overview" Copper.org (http://www.copper.org/publications/newsletter/innovations/1998/06/recycle_overview.html). Kupfer.org (2010-08-25). Accessed 11/08/2011. [24] Balver Zinn Solder Sn97Cu3 (http://www.balverzinn.com/downloads/Solder_Sn97Cu3.pdf). (PDF). balvertin. with. Accessed 11/08/2011. [25] Ralph L. Shriner, Christine KF Hermann, Terence C. Morrill, David Y. Curtin, Reynold C. Fuson "The Systematic Identification of Organic Compounds", 8th Edition, J. Wiley, Hoboken. ISBN 0-471-21503-1 [26] Kay Saalwächter, Walther Burchard, Peter Klüfers, G. Kettenbach and Peter Mayer, Dieter Klemm, Saran Dugarmaa "Cellulose solutions in water with metal complexes" Macromolecules 2000, 33, 4094-4107. [27] "The modern chemistry of organocupper" Norbert Krause, ed., Wiley-VCH, Weinheim, 2002. ISBN 978-3-527-29773-3. [38] Pleger, Thomas C. "A Brief Introduction to the Ancient Copper Complex of the Western Great Lakes: 4000–1000 BC." BCE,” Proceedings of the Twenty-Seventh Annual Meeting of the Wisconsin Forest History Association (http://books.google.com/books?id=6NUQNQAACAAJ), Oconto, Wisconsin, October 5, 2002, pp. 10-18 . [39] Emerson, Thomas E. and McElrath, Dale L. Archaic Societies: Diversity and Complexity Across the Midcontinent (http://books.google.com/books?id=awsA08oYoskC& pg=PA709), SUNY Press, 2009 ISBN 1 -4384-2701-8.

Copper [52] Pops, Horace, 2008, Wire Processing from Antiquity to the Future, Wire Journal International, junho, S. 58–66 [53] The Metallurgy of Copper Wire, http://www. fio litz. com/pdf%20files/ Metallurgy_Copper_Wire. pdf [54] Joseph, Günter, 1999, Copper: Its Trade, Manufacture, Use, and Environmental Status, herausgegeben von Kundig, Konrad J.A., ASM International, S. 141–192 e S. 331–375. [56] Joseph, Günter, 1999, Copper: Its Trade, Manufacture, Use, and Environmental Status, herausgegeben von Kundig, Konrad J.A., ASM International, S.348 [58] IE3 Energy Saving Motors, Engineer Live, http: // www. engheiro vivo. com/ Design-Engineer/ Motors_and_Drives/ IE3_energy-saving_motors/ 22687/ [59] Energy Efficiency Policy Opportunities for Systems Driven by Electric Motors, International Energy Agency, 2011 Working Paper in the Energy Efficiency Series, de Paul Waide e Conrad U. Brunner, OECD/IEA 2011 [60] Fuchsloch, J. e E. F. Brush, (2007), „Systematic Design Approach for a New Series of Ultra-NEMA Premium Copper Rotor Motors“, in Proceedings of the EEMODS 2007 conference, June 10-15, Peking . [61] Projeto de Rotor de Motor em Cobre; Associação de Promoção do Cobre; http://www. cobre. org/ aplicações/ elétrica/ motor-rotor [62] NEMA Premium Motors, Medical Imaging and Electrical Equipment Manufacturers Association; http://www. nein. org/ gov/ energia/ eficiência/ prêmio/ [63] Seale, Wayne (2007). O papel do cobre, latão e bronze na arquitetura e design; Arquitetura Metalica, Mai 2007 [64] Telhados de cobre em detalhe; Cobre na Arquitetura; Copper Development Association, Reino Unido, www.cda.org.uk/arch [65] Arquitetura, European Copper Institute; http://eurocobre. org/ cobre/ arquitetura de cobre. html [66] Kronborg concluído; Agentur für Schlösser und Kulturgüter, København, http://www. slke dk/ en/ slotteoghaver/ slotte/ kronborg/ kronborgshistorie/ kronborgfaerdigbygget. aspx?highlight=kupfer [68] Considerações arquitetônicas; Manual de Project de Cobre em Arquitetura, http://www. cobre. org/ aplicativos/ arquitetura/ arch_dhb/ fundamentos/ arch_considerations. htm [69] Peters, Larry E. (2004). Prevenção de corrosão em sistemas de coberturas de cobre; Professional Roofing, Ende 2004, http://www. coberturas profissionais. net [70] Reação de oxidação: Por que a Estátua da Liberdade é verde-azuda? Envolver os alunos na engenharia; www.EngageEngineering.org; Chun Wu, Ph.D., Universität Mount Marty; Financiado pela National Science Foundation (NSF) Sob Grant Nr. 083306. http:/ / www. wepanwissenszentrum. org/ c/ document_library/ get_file?folderId=517& name=DLFE-2454. pdf [71] Yahoo! Respostas – De que é feita a pátina de uma moeda de cobre oxidado? http://sg. Repostas tun Yahoo. com/ question/ index?qid=20090726064632AAiDf2k [72] K.P. Fitzgerald, J. Nairn, A. Atrens (1998). A química da patinação de cobre; ScienceDirect.com – Corrosion Science – Band 40, Número 12, Dezember 1998, Seiten 2029–2050; http://www. ciência reta. com/ ciência/ artigo/ pii/ S0010938X98000936 [73] Anwendungsgebiete: Arquitetura – Acabamentos – pátina; http://www. cobre. org/ aplicações/ arquitetura/ acabamentos. html [74] Glossário de termos de cobre, Copper Development Association (Reino Unido): http://www. cobreinfo. co. uk/ recursos/ glossário. shtml [75] Acabamentos: envelhecimento natürlich; Copper in Architecture Design Handbook, Copper Development Association Inc., http://www. cobre. org/applications/architecture/arch_dhb/finishing/finishing. html [77] Edding, Mario E., Flores, Hector und Miranda, Claudio, (1995), Uso experimental de malha de liga de cobre-níquel na maricultura. Teil 1: Viabilidade de utilização em zona temperada; Teil 2: Demonstração de uso em área fria; Relatório final para a International Copper Association Ltd. [78] Comportamento de corrosão de ligas de cobre usadas na aquicultura marinha (http://www.copper.org/applications/cuni/pdf/marine_aquaculture.pdf). (PDF) . cobre.org. Zugang am 11-08-2011. [79] Kupfer-Touch-Oberflächen (http://coppertouchsurfaces.org/antimicrobial/bacteria/index.html). Superfícies táteis de cobre. Zugang am 11-08-2011. [80] Ein EPA-Registra produtos de liga contendo cobre (http://www.epa.gov/ pesticides/factsheets/ copper-alloy-products.htm), Mai 2008 [82] Metrô chileno protegido com cobre antimicrobiano – Noticias ferroviarias de (http :/ / www.rail.co/ 2011/ 07/ 22/ metro-de-chile-protegido-con-cobre-antimicrobialo). Rail.co. Zugang am 11-08-2011. [83] Codelco fornecerá cobre antimicrobiano para novas linhas de metrô (Chile) (http://construpages.com.ve/nl/noticia_nl.php?id_noticia=3032& language=en). Construpages.com.ve. Zugang am 11-08-2011. [84] PR 811 Metro de Chile installiert cobre antimicrobiano (http://www.microbialcopper.com/media/149689/pr811-chilean-subway-installs-antimicrobial-copper.pdf). (PDF). mikrobisches Kupfer. com. Zugang am 11-08-2011. [87] livro eletrônico ISBN 978-94-007-5561-1 eletrônico[88] livro eletrônico ISBN 978-94-007-5561-1 eletrônico[89] S. J. Lippard, J. M. Berg "Princípios de Química Bioinrias de Cinica" Livros : Mill Valley, Kalifornien; 1994. ISBN 0-935702-73-3.

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Notes Pourbaix diagrams for copper

in pure water or in acidic or alkaline conditions. Copper in neutral water is nobler than hydrogen.

in sulphurous water

in 10 M Ammoniaklösung

in a chloride solution

Further Reading • Massaro, Edward J., ed. (2002). Manual of Copper Pharmacology and Toxicology. human press. ISBN 0-89603-943-9. • "Copper: Technology and Competitiveness (Summary) Chapter 6: Copper Production Technology" (http://www.princeton.edu/~ota/disk2/1988/8808/880808.PDF). Technology Assessment Office. 2005. • Current Medicinal Chemistry, Vol. 12, Number 10, May 2005, pp. 1161–1208(48) Metals, toxicity and oxidative stress • William D. Callister (2003). Materials Science and Engineering: An Introduction, 6th ed. Table 6.1, pg. 137: Wiley, New York. ISBN 0-471-73696-1. • Material: Copper (Cu), Bulk (http://www.memsnet.org/material/coppercubulk/), MEMS and Nanotechnology Clearinghouse. • Kim BE, Nevitt T, Thiele DJ (2008). "Copper Acquisition, Distribution and Regulation Mechanisms" (http://www.nature.com/nchembio/journal/v4/n3/abs/nchembio.72.html). Chemical Nat. biol. 4(3): 176-85. doi: 10.1038/nchembio.72 (http://dx.doi.org/10.1038/nchembio.72). PMID 18277979 (http://www.ncbi.nlm.nih.gov/pubmed/18277979). • Copper transport perturbations (http://www.rsc.org/Publishing/Journals/cb/Volume/2009/1/Copper.asp): A snapshot from the Royal Society of Chemistry

copper

External Links • Copper (http://www.periodicvideos.com/videos/029.htm) in the Periodic Table of Videos (University of Nottingham) • National Pollutant Inventory – Fact Sheet on Copper and Compounds (http://www. .npi .gov .au/substances/copper/index.html) • Copper resource page. (http://www.weldaloy.com/resource_center.php) Includes 12 PDF files detailing the material properties of different types of copper, as well as numerous guides and tools for the copper industry. • CDC: NIOSH Pocket Guide to Chemical Hazards: Copper (Posts and Mists) (http://www.cdc.gov/niosh/npg/npgd0150.html) • CDC: NIOSH Pocket Guide to Chemical Hazards: Copper Fume (http: //www.cdc.gov/niosh/npg/npgd0151.html) • The Copper Development Association (http://www.copper.org) has an extensive website on the properties and uses of copper; also maintains a website dedicated to brass (http://www.brass.org), an alloy of copper. • The Third Millennium Copper Online site (http://www.3rd1000.com/elements/Copper.htm) • IMF Copper Price History (http://www.indexmundi.com/commodities /?commodity =copper&months =300)

Alloy An alloy is a solid metallic mixture or solution composed of two or more elements.[1] An alloy contains one or more of three: a solid solution of the elements (a single phase); a mixture of metallic phases (two or more solutions); an intermetallic compound with no defined boundary between phases. Solid solution alloys provide a single solid phase microstructure, while partial solutions provide two or more phases that may or may not be homogeneously distributed depending on the thermal history (heat treatment) of the material. An intermetallic compound has another alloy or pure metal embedded in another pure metal. Alloys are used because their properties are superior to pure component elements. Examples of alloys are solder, brass, tin, phosphor bronze and amalgam. Alloy components are usually measured by mass. The alloys are steel cables, a metallic alloy, generally classified as substitute or interstitial alloy, depending on which the main component is iron, with a carbon content between 0.02 and 2.14% by mass. the atomic arrangement that forms the alloy. They can be further classified as homogeneous (consisting of a single phase), heterogeneous (consisting of two or more phases), or intermetallic (where there is no sharp boundary between the phases).

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Introduction An alloy is a mixture of pure or very pure chemical elements that form an impure substance (mixture) that retains the properties of a metal. An alloy differs from an impure metal such as wrought iron because in an alloy, added impurities are often desirable and usually have a useful benefit. Alloys are made by mixing two or more elements; at least one of which is a metal. This is often referred to as the primary metal or base metal, and the name of this metal can also be the name of the alloy. The other ingredients may or may not be metals, but when mixed with the molten base they are soluble and will dissolve in the mixture. As the alloy cools and solidifies (crystallizes), its mechanical properties often differ significantly from those of its individual components. A normally very soft and malleable metal like aluminum can be modified by joining it to another soft metal like copper. While both metals are very soft and ductile, the resulting aluminum alloy will be much harder and stronger. Adding a small amount of non-metallic carbon to iron creates an alloy called steel. Due to its high strength and toughness (which is much higher than pure iron) and its ability to be greatly altered by heat treatment, steel is one of the most common alloys in modern use. Adding chromium to steel can improve its corrosion resistance, creating stainless steel, while adding silicon changes its electrical properties, creating silicon steel.

Liquid bronze poured into molds during casting.

A gate valve made of Inconel.

Although elements are generally required to be soluble in the liquid state, they are not always required to be soluble in the solid state. If the metals remain soluble in the solid state, the alloy forms a solid solution and becomes a homogeneous structure of identical crystals called a phase. When the mixture is cooled and the components become insoluble, they can separate to form two or more different types of crystals, creating a heterogeneous microstructure of different phases. However, in other alloys, insoluble elements cannot separate out until crystallization occurs. These alloys are called intermetallic alloys because if they cool down too quickly, they initially crystallize as a homogeneous phase, but then become supersaturated with the secondary components. Over time, the atoms of these supersaturated alloys separate within the crystals, forming intermetallic phases that serve to strengthen the crystals internally. Some natural alloys such as electro, an alloy of silver and gold native to Earth. Meteors are sometimes made from natural iron and nickel alloys, but they are not native to Earth. One of the first man-made alloys was bronze, made from a mixture of tin and copper. Bronze was an extremely useful alloy to the ancients, being much stronger and harder than any of its constituents. Steel was another common alloy. In ancient times, however, it could only be produced as an accidental by-product of heating iron ore in (smelter) fires during iron production. Other ancient alloys are tin, brass and pig iron. In modern times, steel can be processed in many ways. Carbon steel can be made simply by varying the carbon content, resulting in soft alloys like mild steel or hard alloys like spring steel. Steel alloys can be made by adding other elements such as molybdenum, vanadium, or nickel, resulting in alloys such as high-speed steel or tool steel. Small amounts of manganese are usually alloyed with most modern steels because of its ability to remove unwanted impurities such as phosphorus, sulfur and oxygen that can adversely affect the alloy. However, most alloys were not produced until around 1900, such as various aluminum, titanium, nickel and magnesium alloys.

Alloy Some modern superalloys such as Incoloy, Inconel and Hastelloy can be composed of several different components.

Terminology The term alloy denotes a mixture of atoms whose main component is a metal. The primary metal is called the base, matrix or solvent. Minor components are often referred to as solutes. If there is a mixture of only two types of atoms, not counting impurities, such as B. an alloy of copper and nickel, one speaks of a binary alloy. When there are three types of atoms that make up the mixture, such as iron, nickel, and chromium, it is called a ternary alloy. A four component alloy is referred to as a quaternary alloy while a five component alloy is referred to as a quinary alloy. Because the percentage of each ingredient in each mix can vary, the full range of possible variations is called a system. In this context, all the different forms of an alloy containing only two components, such as iron and carbon, are called the binary system, while all possible alloy combinations with a ternary alloy, such as alloys of iron, carbon and chromium, are called the binary system. is called the ternary system.[2] Although an alloy is an impure metal, the term "impurities" when referring to alloys generally denotes those elements that are not desired. These impurities are often found in base metals or solutes, but they can also be introduced during the alloying process. For example, sulfur is a common impurity in steel. Sulfur easily combines with iron to form iron sulfide, which is very brittle and creates weak points in steel.[3] Lithium, sodium, and calcium are common impurities in aluminum alloys that can compromise the structural integrity of castings. On the other hand, pure metals that simply contain unwanted impurities are often referred to as "impure metals" and are not generally referred to as alloys. Oxygen present in air readily combines with most metals to form metal oxides; especially at the higher temperatures encountered in alloying. During the alloying process, great care is often taken to remove excess impurities using fluxes, chemical additives, or other extractive metallurgical methods.[4] In practice, some alloys are so prevalently used in relation to their base metals that the designation of the main constituent is also used to designate the alloy. For example, 14k gold is an alloy of gold with other elements. Likewise, silver used in jewelry and aluminum used as a structural building material are also alloys. The term "alloy" is sometimes used in everyday language as a synonym for a specific alloy. For example, automobile wheels made of aluminum alloy are commonly referred to simply as "alloy wheels", when in actuality steels and most other metals are also alloys in practical use.

theory

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A metal is alloyed by combining it with one or more metals or non-metals, often increasing its properties. For example, steel is stronger than iron, its main element. An alloy's physical properties such as density, reactivity, elastic modulus, and electrical and thermal conductivity may not differ significantly from those of its elements, but engineering properties such as tensile strength[5] and shear strength may differ significantly from those of its elements. those of the constituent materials. Sometimes this is a result of the size of the atoms in the alloy, since larger atoms exert a compressive force on neighboring atoms and smaller atoms exert a tensile force on neighbors, which helps the alloy resist deformation. Alloys can sometimes show significant differences in behavior even when small amounts of an element are present. For example, impurities in ferromagnetic semiconductor alloys result in different properties, as first predicted by White, Hogan, Suhl, Tian Abrie, and Nakamura.[6][7] Some alloys are made by melting and mixing two or more metals. Bronze, an alloy of copper and tin, was the first alloy discovered during the prehistoric period now known as the Bronze Age; Harder than pure copper, it was originally used to make tools and weapons, but was later replaced by metals and alloys with better properties. In later times bronze was used for ornaments, bells, statues and bearings. Brass is an alloy of copper and zinc. Unlike pure metals, most alloys do not have a single melting point but instead have a melting range where the material is a mixture of solid and liquid phases. The temperature at which melting begins is called the solidus, and the temperature at which melting is just completed is called the liquidus. However, in most alloys there is a certain proportion of constituents (rarely two), the eutectic mixture, which gives the alloy a unique melting point.

replacement and intermediate alloys

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When a molten metal is mixed with another substance, there are two mechanisms that can lead to the formation of an alloy, called the atomic exchange and the interstitial mechanism. The relative size of each atom in the mixture plays an important role in determining which mechanism occurs. When the atoms are relatively similar in size, the atom exchange method usually occurs, in which some of the atoms that make up the metal crystals are replaced with atoms of the other constituent. This is called a replacement alloy. Examples of substitutional alloys are bronze and brass where some of the copper atoms are replaced with tin, or various atomic alloying mechanisms that have pure metal substitution zinc atoms. With the Interstitial Interstitial and a combination of both. mechanism, one atom is usually much smaller than the other, so it cannot successfully replace an atom in the base metal crystals. The smallest atoms are trapped in the spaces between atoms in the crystalline matrix, called interstices. This is known as interstitial alloying. Steel is an example of an interstitial alloy because very small carbon atoms fit into the interstices of the iron matrix. Stainless steel is an example of a combination of interstitial and substitutional alloys because the carbon atoms fit into the interstices but some of the iron atoms are replaced with nickel and chromium atoms.[8]

Heat Treatable Alloys Alloys are often made to alter the mechanical properties of the base metal to induce hardness, toughness, ductility, or other desired properties. Most metals and alloys can be hardened, creating defects in their crystal structure. These defects arise from plastic deformation such as hammering or bending and are permanent unless the metal is recrystallized. However, the properties of some alloys can also be modified by heat treatment. Almost all metals can be allotropes of iron (alpha iron and gamma iron) that are softened by annealing, which recrystallizes the alloy and repairs differences in atomic arrangement. Defects, but not many, can be hardened with controlled heating and cooling. Many aluminum, copper, magnesium, titanium, and nickel alloys can be strengthened to some degree by heat treatment processes, but few respond like steel.[8] At a certain temperature (usually between 820 °C (1500 °F) and 870 °C (1600 °F)), the base metal of steel (iron) undergoes a change in the arrangement of the atoms in its crystalline matrix called allotropy. This allows small carbon atoms to penetrate into the interstices of the crystal,

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Diffusion into the iron matrix. When this happens, the carbon atoms are said to be in solution or mixed with the iron, forming a single homogeneous crystalline phase called austenite. As steel slowly cools, iron gradually changes to its low-temperature allotrope. When this happens, the carbon atoms are no longer soluble with the iron and are forced to fall out of solution, nucleating in the interstices between the crystals. The steel then becomes heterogeneous and consists of two phases; the carbon phase (carbide) cementite and ferrite (iron). This type of heat treatment produces a very soft and flexible steel. However, if the steel cools quickly, the carbon atoms don't have time to separate. On rapid cooling, a non-diffusive transformation (martensite) occurs, trapping carbon atoms in solution. This causes iron crystals to inherently warp as the crystal structure attempts to transition to its low temperature state, making them very hard and brittle.

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Steel photomicrographs. The top photo shows an annealed steel (slowly cooled) forming a heterogeneous lamellar microstructure called pearlite, composed of cementite (light) and ferrite (dark) phases. The bottom photo is hardened (rapidly cooled) steel in which carbon remains trapped in martensite crystals, creating internal stresses.

On the other hand, most heat treatable alloys are precipitation hardened, which produces the opposite effects of steel. When these alloys are heated to form a solution and then rapidly cooled, they become much softer than normal during the non-diffusing transformation and then harden as they age. Solutes in these alloys will precipitate over time, forming intermetallic phases that are difficult to distinguish from the base metal. Unlike steel, where the solid solution separates to form different crystalline phases, precipitation hardening alloys separate to form different phases within the same crystal. These intermetallic alloys appear to have a homogeneous crystal structure but tend to behave heterogeneously, becoming hard and somewhat brittle.[8]

History Meteoric Iron Man's use of alloys began with the use of meteoric iron, a natural alloy of nickel and iron. Since no metallurgical process was used to separate the iron from the nickel, the alloy was used unmodified.[9] Meteorite Iron can be forged from Red Ember to create items such as tools, weapons, and nails. In many cultures it was cold hammered into knives and arrowheads. They were often used as anvils. Meteoritic iron was very rare and valuable, and difficult for ancient people to work with.[10]

bronze and brass

A meteorite is depicted beneath an ax forged from meteoric iron.

Iron is generally found as iron ore on Earth, with the exception of an indigenous iron deposit in Greenland that was exploited by the Inuit.[11] However, native copper has been found all over the world, along with silver, gold, and platinum, which has also been used to make tools, jewelry, and other items since Neolithic times. Copper was the hardest of these metals and the most common. It has become one of the most important.

Liga

metals for the elderly. Eventually, humans learned to smelt metals like copper and tin from ores, and around 2500 B.C. C. began combining the two metals into bronze, which is much harder than its component parts. However, pewter was rare and found mainly in Britain. In the Middle East, copper began to be alloyed with zinc to form brass.[12] Ancient civilizations took into account mixing and the various properties it produced, such as hardness, toughness, and melting point, under different temperature and hardening conditions, and developed much of the information contained in the phase diagrams of modern alloys.[13]

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Bronzeaxt 1100 v

Mercury amalgams have been fused from cinnabar for thousands of years. Mercury dissolves many metals such as gold, silver and tin to form amalgams (an alloy in the form of a slurry or liquid at room temperature). Amalgams have been made since 200 BC. used. C. In China, for plating objects with precious metals called gold, such as armor and mirrors. The ancient Romans used mercury and tin amalgams to gild their armor. The amalgam was applied as a paste and then heated until the mercury evaporated, leaving behind gold, silver, or tin.[14] Mercury was often used in mining to extract precious metals such as gold and silver from their ores.[15] A brass lamp.

Alloys of Precious Metals Many ancient civilizations alloyed metals for purely aesthetic reasons. In ancient Egypt and Mycenae, gold was often mixed with copper to make pink gold, or with iron to make a bright burgundy gold. Silver was often found mixed with gold. These metals were also used to reinforce each other for more practical purposes. Precious metals were often mixed with less valuable substances to fool buyers.[16] Around 250 BC In BC, the king commissioned Archimedes to find a way to check the purity of gold in a crown, leading to the famous cry "Eureka!". on the discovery of the Archimedean principle.[17]

Electro, a natural alloy of silver and gold, was often used to make coins.

Steel and pig iron The first known iron smelting began in Anatolia around 1800 BC. Called the flowering process, it produced very soft but ductile wrought iron, and around 800 B.C. C. the technology had spread to Europe. Already 1200 BC Pig iron, a very hard but brittle alloy of iron and carbon, was produced in China. C., but only reached Europe in the Middle Ages. Pig iron has a lower melting point than iron and was used to make cast iron. However, these metals were found until the introduction of crucible steel around 300 BC. little practical use. These steels were of poor quality and the introduction of standard welding occurred around the 1st century AD. C. attempted to compensate for the extreme properties of alloys by rolling them into a stronger metal. Around AD 700, the Japanese began bending steel and cast iron in alternating layers to increase the strength of their swords, and used clay fluxes to remove slag and impurities. This Japanese method of forging swords produced one of the purest steel alloys of antiquity.[13]

Alloy Although the use of iron began to spread around the year 1200. C., largely due to disruptions in the trade routes for tin, the metal is much softer than bronze. However, very small amounts of steel (an alloy of iron and about 1% carbon) are always a by-product of the blooming process. The ability to change the hardness of steel through heat treatment has been around since 1100 BC. known. C., and the rare material was valued for its use in the manufacture of tools and weapons. Since the ancients could not generate temperatures high enough to melt iron completely, adequate steel production did not occur until the introduction of hollow-core steel in the Middle Ages. In this process, carbon was introduced into carbon by heating wrought iron for a long time, but the penetration of carbon was not very deep, so the alloy was not homogeneous. In 1740, Benjamin Huntsman began melting honeycomb steel in a crucible to offset the carbon content, creating the first process for mass-producing tool steel. The Huntsman process was used to make steel tools well into the early 20th century.[18] With the introduction of the blast furnace in Europe in the Middle Ages, pig iron could be produced in much larger quantities than wrought iron. Because pig iron could be melted, people began to develop methods to reduce the carbon in liquid pig iron to make steel. Casting was introduced in the 17th century, where molten pig iron was stirred while exposed to air to remove carbon through oxidation. In 1858, Sir Henry Bessemer developed a steelmaking process in which hot air was blown through molten pig iron to reduce the carbon content. The Bessemer process was able to produce the first large-scale steel manufacture.[18] As the Bessemer process became widespread, other steel alloys began to follow. Mangalloy, an alloy of steel and manganese that exhibits extreme hardness and toughness, was one of the first steel alloys and was developed by Robert Hadfield in 1882.[19]

Precipitation Hardening Alloys In 1906 Alfred Wilm discovered precipitation hardening alloys. Precipitation hardening alloys, such as certain aluminum, titanium, and copper alloys, are heat-treatable alloys that soften (quickly cool) upon cooling and then harden over time. After quenching an aluminium-copper-magnesium ternary alloy, Wilm found that the hardness of the alloy increased as it was aged at room temperature. Although no explanation for the phenomenon was provided until 1919, duralumin was one of the first "age-hardening" alloys used, and many others soon followed. Because they often offer a combination of high strength and low weight, these alloys have found widespread use in many industries, including modern aircraft construction.[20]

References [1] [2] [3] [4] [5]

(http://www.thefreedictionary.com/liga) Michael Bauccio (2005) ASM Metals Reference Book, ASM International 2005 Steel Metalurgy for the Non-Metallurgist By John D. Verhoeven - ASM International 2007 Page 56 ASM Expert Handbook: Aluminum and Aluminum Alloys By Joseph R. Davis - ASM International Page 211 Adelbert Phillo Mills, (1922) Building Materials: Their Manufacture and Properties, John Wiley & Sons, Inc., originally published by the University of Wisconsin, Madison [8] Jon L. Dossett , Howard E. Boyer (2006) Practical Heat Treatment, ASM International, pp. 1-14 [10] Vagn Fabritius Buchwald Iron and Steel in Antiquity, Det Kongelige Danske Videnskabernes Selskab 2005 pp. 13–22 [11] Vagn Fabritius Buchwald Iron and Steel in Antiquity, Royal Danish Society for Science 2005 pp. 35-37 [12] Vagn Fabritius Buchwald Iron and Steel in Antiquity, Royal Danish Society for Science 2005 pp. 39-41 [13] Cyril Smith (1960) History of Metal lographie and, MIT Press, ISBN 0-262-69120-5 pp. 2-4 [14] George Rapp (2009) Archaeomineralogy (http:///books.Google.com/books?id=ed0yC98aAKYC&pg=PA180), Springer , page 180 ISBN 3-540-78593-0 [15] Harry A Miskimin (1977) The Economics of Later Renaissance Europe, 1460–1600 (http://books.google.com/books?id=QE04AAAAIAAJ& pg=PA31) , Cambridge University Press, ISBN 0-521-29208-5, p. . 31 [16] Paul T Nicholson, Ian Shaw (2000) Ancient Egypt materials and technology (http://books.google.com/books?id=Vj7A9jJrZP0C&pg=PA164), Cambridge University Press, ISBN 0-521-45257 - 0 pp. 164–167 [17] Melvyn Kay (2008) Practical Hydraulics (http://books.google.com/books?id=xCtAV_MCD1EC& pg=PA45), Taylor and Francis, ISBN 0-415-35115-4 p . 45 [18] George Adam Roberts, George Krauss, Richard Kennedy, Richard L. Kennedy (1998) Tool steels (http://books.google.com/books?id=ScphevR_eP8C& pg=PA2), ASM International, ISBN 0 - 87170 -599-0pp. 2–3 [19] Cast steel: Austenitic manganese steels (http://www.keytometals.com/Articles/Art69.htm)

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League [20] http://www. comparative slides. Mesh/ Core Materials/ Talat-lecture-1204-precipitation-hardening-2318135

External links • Chisholm, Hugh, ed. (1911). "Leagues" Encyclopædia Britannica (11th ed.). Cambridge University Press. • Surface bands (http://www.uni-ulm.de/~hhoster/staff/surface_alloys.html)

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Lata

137

1950s Sn 1950s

Indium ← Zinn → AntimonGe ↑

Sn ↓ Pb tin on the periodic table appearance silvery (left, beta) or gray (right, alpha)

General Properties Name, Symbol, Number

Tin, Sn, 50

pronunciation

/tɪn/

item category

Metal weapons

group, period, block

14, 5, p.

standard atomic weight

118.710

Lata

138 Electronic configuration

[Kr] 4d10 5s2 5p2 2, 8, 18, 18, 4

discovery of history

around 3500 BC C. Physical Properties

Phase

fest

Density (near room temperature)

(branco) 7,365 g·cm−3

Density (near room temperature)

(gris) 5,769 g·cm−3

Density of the liquid in m.p.

6,99 g·cm−3

fusion point

505,08 K, 231,93 °C, 449,47 °F

boiling point

2875K, 2602°C, 4716°F

heat of fusion

(branco) 7,03 kJ·mol−1

heat of vaporization

(branco) 296,1 kJ·mol-1

molar heat capacity

(white) 27.112 J mol-1 K-1 vapor pressure

P (Pa)

100

1 k

10 thousand 100 thousand

at T (K) 1497 1657 1855 2107 2438 2893 Atomic properties [1]

[2]

oxidation states

4, 3

electronegativity

1.96 (Pauling Scale)

ionization energies

1.: 708.6 kJ mol-1

, 2, 1

, -4 (amphoteres Oxid)

2.: 1411,8 kJ mol−1 3.: 2943,0 kJ mol−1 Atomradius

140 hours

covalent ray

139±16h

Radio Van der Waals

217h Miscellaneous

Lata

139 crystal structure

tetragonal

cubic white diamond

grau [3]

magnetic request

(grey) diamagnetic

Electrical resistance

(0 °C) 115 nΩ·m

thermal conductivity

66,8 W·m−1·K−1

thermal expansion

(25 °C) 22,0 µm·m−1·K−1

, (white) paramagnetic

Speed of sound (thin bar) (r.t.) (wrapped) 2730m s−1 Modulus of elasticity

50 GPa

Schneidmodul

18 GPa

Volumenmodul

58 GPa

poison ratio

0,36

Mohs hardness

1,5

Brinell hardness

~350 MPa

CAS registration number

7440-31-5 More stable isotopes Main article: Tin isotopes

You are so

THE

half-life

Sn 0,97%

112

Sn 0,66 %

114

Sn 0,34 %

115

SN 14,54 %

116

Sn 7,68%

117

Sn 24,22%

118

Sn 8,59%

119

Sn 32,58%

120

Sn 4,63%

122

112 114 115 116 117 118 119 120 122

Sn 5,79%

124 126

nice

path

DM OF (MeV)

Sn is stable at 62 neutrons Sn is stable at 64 neutrons Sn is stable at 65 neutrons Sn is stable at 66 neutrons Sn is stable at 67 neutrons Sn is stable at 68 neutrons Sn is stable at 69 neutrons Sn is stable at 70 neutrons Sn is stable with 72 neutrons

>1×1017 e β−β−

2,2870

124

2.3 × 105 years

0,380 +

126

b−

Him

Lata

140

Tin is a chemical element with the symbol Sn (Latin: stannum) and the atomic number 50. It is a main group metal of the 14th group of the periodic table. Tin shows chemical resemblance to its two neighboring Group 14 elements, germanium and lead, and has two possible oxidation states, +2 and the slightly more stable +4. Tin is the 49th most common element and has the highest number of stable isotopes on the periodic table with 10 stable isotopes. Tin is primarily extracted from cassiterite ore, where it occurs as tin dioxide, SnO2. This malleable, silvery post-transition metal does not readily rust in air and is used to coat other metals to prevent corrosion. The first alloy to be used extensively from the year 3000 AD. C., was bronze, an alloy of tin and copper. After 600 BC C. Pure metallic tin was produced. An alloy of 85 to 90% tin, with the balance usually being copper, antimony and lead. Tin was used for cutlery from the Bronze Age through the 20th century. Today, tin is used in many alloys, particularly tin/lead solders, which typically contain 60% or more tin. Another major use for tin is in the tinning of stainless steel. Due to its low toxicity, tinned metal is also used for packaging food and gives its name to cans, which are mostly made of steel.

Properties Physical Properties Tin is a malleable, ductile, highly crystalline, silvery-white metal. When a tin ingot is bent, a sound known as tinning can be heard due to the twinning of the crystals. [] Tin melts at a low temperature of about 232 °C (449.6 °F), which drops to 177.3 °C (351 °F) for 11 nm particles.[4] β-Tin (the metallic form or white tin), which is stable at and above room temperature, is malleable. In contrast, α-tin (nonmetallic form or gray tin), which is stable below 13.2 °C (56 °F), is brittle. α-Tin has a cubic diamond crystal structure, similar to diamond, silicon, or germanium. α-Tin has no metallic properties as its atoms form a covalent structure in which the electrons cannot move freely in the solidified molten tin. It is an opaque, gray powder material that has no common uses beyond a few specialized semiconductor applications. [ ] These two allotropes, α-tin and β-tin, are better known as gray tin and white tin, respectively. Two other allotropes, γ and σ, exist at temperatures above 161 °C (322 °F) and pressures above several GPa.[5] Under cold conditions, β-tin tends to spontaneously convert to α-tin, a phenomenon known as "tin plague".[6] Although the α-β transformation temperature is nominally 13.2 °C, impurities (e.g. Al, Zn, etc.) lower the transformation temperature well below 0 °C (32 °F) and the addition of Sb or Bi can enhance the transformation stay away at all, which increases the durability of tin. [] Commercial grades (99.8%) of tin resist conversion due to the inhibiting effect of small amounts of bismuth, antimony, lead and silver present as impurities. Alloying elements such as copper, antimony, bismuth, cadmium and silver increase its hardness. Tin tends to form hard and brittle intermetallic phases which are often undesirable. It does not generally form wide ranges of solid solutions in other metals, and few elements have appreciable solid solubility in tin. However, simple eutectic systems occur with bismuth, gallium, lead, thallium, and zinc. [ ] Tin becomes a superconductor below 3.72 K. [7] In fact, tin was one of the first superconductors studied; The Meissner effect, one of the hallmarks of superconductors, was first discovered in superconducting tin crystals.[]

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141

Chemical properties Tin resists corrosion by water but can be attacked by acids and alkalis. Tin can be highly polished and serves as a protective layer for other metals. [ ] In this case, the formation of a protective oxide layer is used to prevent further oxidation. This oxide layer forms on tin and other tin alloys.[8] Tin acts as a catalyst when oxygen is in solution and helps accelerate corrosion.[ ]

Isotopes Tin is the element with the highest number of stable isotopes, ten, with atomic masses 112, 114–120, 122, and 124. Of these, the most common are 120Sn (almost a third of all tin), 118Sn, and 116Sn, while 115Sn comes in the least Before. Even isotopes have no nuclear spin, while odd have +1/2 spin. Tin, with its three common isotopes 115Sn, 117Sn, and 119Sn, is among the easiest elements to detect and analyze using NMR spectroscopy, and its chemical shifts are comparable to those of SnMe[9][10]4 which can be a direct result of tin with an atomic number of 50, which is a "magic number" in nuclear physics. Another 28 unstable isotopes are known, including all others with atomic masses between 99 and 137. With the exception of 126Sn, which has a half-life of 230,000 years, all radioactive isotopes have half-lives of less than one year. The radioactive 100Sn is one of the few nuclides with a "double magic" nucleus and was only discovered relatively recently, in 1994.[11] Another 30 metastable isomers have been characterized for isotopes between 111 and 131, the most stable being 121mSn with a half-life of 43.9 years.

Etymology The English word "zinn" is Germanic; related words are found in the other Germanic languages (German zinn, Swedish tenn, Dutch tin, etc.) but not in other branches of Indo-European except through borrowing (e.g. Irish tinne). Its origin is unknown.[12] The Latin name Stannum originally meant an alloy of silver and lead and was used in the 4th century BC. to "tin". C [13]; the former Latin word for it was plumbum candidum "white lead". Stannum apparently came from an earlier stāgnum (meaning the same substance),[12] the origin of the Roman and Celtic terms for "tin".[12][14] The origin of Stannum/Stāgnum is unknown; may be pre-Indo-European.[15] The Meyers Konversationslexikon, on the contrary, speculates that pewter came from Cornish steel and is evidence that in the early centuries AD Cornish was the main source of pewter.

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142

History The mining and use of tin dates back to the early Bronze Age around 3000 BC. back. C. when it was observed that copper objects formed from polymetallic minerals with different metal contents had different physical properties.[16] Early bronze objects had less than 2% tin or arsenic content and are therefore probably the result of inadvertent alloying due to the residual metal content in the copper ore. [] Adding a second metal to copper increases its hardness, lowers its melting temperature, and improves the casting process, creating a more fluid melt that cools to a denser, less spongy metal.[] This was an important innovation, cooling a denser, less spongy metal. less spongy metal. [] This was an important innovation, allowing much more complex shapes to be cast in closed Bronze Age moulds. Arsenic bronze objects first appear in the Middle East, where arsenic is often found associated with copper ore, but health hazards were quickly identified as Plougrescant-Ommerschans, Plougrescant, France, 1500–1300 BC type. and the search for much less dangerous sources of tin ore [17] began in the early Bronze Age. This created a demand for rare metallic tin and formed a trade network linking distant sources of tin to the markets of Bronze Age cultures.

Cassiterite (SnO2), the tin oxide form of tin, was probably the original source of tin in ancient times. Other forms of tin ores are the less abundant sulfides, such as stannite, which require a more complex smelting process. Cassiterite commonly accumulates in alluvial channels such as alluvial deposits because it is harder, heavier, and more chemically resistant than the granite in which it normally forms.[18] These deposits are easy to see on riverbanks, as cassiterite is usually black, purple, or some other dark color, a property exploited by Bronze Age prospectors. It is likely that the earliest deposits were alluvial in nature and may have been mined using the same methods used to pan for gold in alluvial deposits. [citation required]

Compounds and chemistry Tin has oxidation state II or IV in most of its compounds.

Inorganic compounds Halogen compounds are known for both oxidation states. For Sn(IV) the four halides are well known: SnF4, SnCl4, SnBr4 and SnI4. The three heaviest members are volatile molecular compounds while tetrafluoride is polymeric. The four halides are also known for Sn(II): SnF2, SnCl2, SnBr2 and SnI2. They are all polymeric solids. Of these eight compounds, only iodides are colored. [ ] Stannous chloride (also known as stannous chloride) is the most commercially important tin halide. To illustrate the pathways for such compounds, chlorine reacts with metallic tin to give SnCl4, while the reaction of hydrochloric acid and tin gives SnCl2 and hydrogen gas. Alternatively, SnCl4 and Sn combine to form tin chloride through a process called partitioning:[19] SnCl4 + Sn → 2 SnCl2 Tin can form many oxides, sulfides, and other chalcogenide derivatives. SnO2 dioxide (kasiterite) is formed when tin is heated in the presence of air.[] SnO2 is amphoteric, meaning that it dissolves in both acidic and basic solutions.[20] There are also stannates with the structure [Sn(OH)6]2−, such as K2[Sn(OH)6], although the free stannic acid H2[Sn(OH)6] is unknown. Tin sulfides exist in the +2 and +4 oxidation states: tin(II) sulfide and tin(IV) sulfide (mosaic gold).

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Stannous anhydrides (SnH4), where tin is in the +4 oxidation state, are unstable. However, organotin hydrides are well known, for example tributyltin hydride (Sn(C4H9)3H).[] These compounds liberate transient tributyltin radicals, rare examples of tin(III) compounds.[22]

organotin compounds

Ball and stick models of the structure of solid tin chloride [21] (SnCl2).

Organotin compounds, sometimes called stannanes, are chemical compounds containing tin–carbon bonds.[23] Of the tin compounds, the organic derivatives are the most commercially useful.[24] Some organotin compounds are highly toxic and have been used as biocides. The first known organotin compound was diethyltin diiodide ((C2H5)2SnI2), reported by Edward Frankland in 1849.[25] Most organotin compounds are colorless liquids or solids that are stable in air and water. They adopt a tetrahedral geometry. Tetraalkyl and tetraaryltin compounds can be prepared using the Grignard reagents:[24] SnCl 4 + 4 RMgBr → R 4Sn + 4 MgBrCl Mixed halide alkyls, which are more common and commercially more important than tetraorgan derivatives, are prepared by rearrangement reactions: SnCl 4+ R 4Sn → 2 SnCl R 2 2 Divalent organotin compounds are uncommon, although more common than related divalent organosilicon and organogermanium compounds. The greater stabilization of Sn(II) is attributed to the "inert pair effect". Organotin(II) compounds include stanylenes (formula: R2Sn, as in singlet carbenes) and disthalenes (R4Sn2), which are roughly equivalent to alkenes. Both classes show unusual reactions.[26]

Occurrence Tin is produced by the long S-process in low to intermediate mass stars (with masses from 0.6 to 10 solar masses). It is formed by the beta decay of heavy indium isotopes.[27] Tin is the 49th most abundant element in the earth's crust, accounting for 2 ppm compared to 75 ppm for zinc, 50 ppm for copper, and 14 ppm for lead.[28] Tin does not occur as a natural element, but has to be extracted from various ores. Cassiterite (SnO2) is the only commercial specimen of cassiterite, the principal tin ore. Important source of tin, although small quantities of tin are recovered from complex sulphides such as stannite, cylindrite, frankite, canfieldite and thealite. Tin-bearing minerals are almost always associated with granitic rock, typically at 1% tin oxide content.[]

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144 Due to the higher specific gravity of tin dioxide, approximately 80% of the mined tin comes from secondary deposits downstream of the primary veins. Tin is often obtained from pellets that have historically been extracted downstream and deposited in valleys or on the seabed. The cheapest methods of extracting tin are dredging, hydraulic methods or open pit mining. Most of the world's tin is extracted from alluvial deposits, which can contain as little as 0.015% tin.[29]

Granular pieces of cassiterite collected by alluvial mining.

World Tin Mine Reserves (tonnes, 2011)[] Country China

Reserves 1,500,000

Malaysia 250,000 Peru

310.000

Indonesia 800,000 Brazil

590.000

Bolivia

400.000

Russia

350.000

Thailand

170.000

Australia 180,000 Others

180.000

In total

4.800.000

Around 253,000 tons of tin were mined in 2011, mainly in China (110,000 tons), Indonesia (51,000 tons), Peru (34,600 tons), Bolivia (20,700 tons) and Brazil (12,000 tons). historically it has varied with the dynamics of economic viability and development of mining technologies, but it is estimated that at current consumption rates and technologies the earth will run out of mineable tin within 40 years.[30] However, Lester Brown has suggested that tin could be depleted within 20 years based on a very conservative extrapolation of 2% annual growth.[]

Economically recoverable tin reserves[] year million tons 1965 4,265 1970 3,930 1975 9,060 1980 9,100 1985 3,060 1990 7,100 2000 7,100[]

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145 2010 5.200[]

Secondary tin or scrap is also an important source of the metal. The recovery of tin through secondary production or scrap tin recycling is increasing rapidly. Although the United States has not mined tin since 1993 or smelted tin since 1989, it was the largest secondary producer, recycling nearly 14,000 tons of tin in 2006. It was discovered in Colombia, South America by Grupo Seminole Colombia CI, SAS.[32][ 33]

Production Tin is produced by carbothermal reduction of the oxidic ore with charcoal or coke. Both flame furnaces and electric furnaces can be used.[34][35][36]

Industry The top ten companies produced most of the world's tin in 2007. It is not clear which of these companies owns tin smelted at the Bisie mine in the Democratic Republic of the Congo, which is controlled by a renegade militia and produces 15,000 tons. Most of the world's tin is traded on the London Metal Exchange (LME) from 8 countries under 17 brands.[37]

Pewter chandelier

Largest Tin Producing Companies (tonnes)[38] companies

government

2006

2007

%To change

Download von Yunnan

porcelain

52.339 61.129 16,7

PT Thymus

Indonesia 44,689 58,325 30.5

Minsur

Peru

40.977 35.940 −12,3

until now

porcelain

52.339 61.129 16,7

Malaysia Smelting Corp. Malaysia 22,850 25,471 11.5 Thaisarco

Thailand

27.828 19.826 −28,8

Yunnan Chengfeng

porcelain

21.765 18.000 −17,8

Lata China von Liuzhou

porcelain

13.499 13.193 −2,3

VITO

Bolivia

11.804 9.448

−20,0

Golden bell group

porcelain

4.696

70,9

8.000

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146

Price and Trade Tin is unique among other mineral products in complex "agreements" between producing and consuming countries dating back to 1921. Early arrangements were rather informal and sporadic; led to the First International Tin Agreement in 1956, the first of a sequentially numbered series that essentially collapsed in 1985. The ITC has supported the tin price in times of low prices due to world production and the (US exchange) price of tin. by buying tin for its reserve stocks and managed to contain the price during periods of high prices by selling tin from the reserve. This was an anti-market approach aimed at ensuring an adequate flow of tin to consuming countries and a reasonable profit for producing countries. However, the reserve pool was not large enough, and for most of those 29 years, tin prices rose, sometimes sharply, particularly between 1973 and 1980 when runaway inflation devastated many of the world's economies.[39] In the late 1970's and early 1980's, the US government's tin reserves were in an aggressive sale mode, in part to take advantage of historically high tin prices. The severe recession of 1981-1982 proved quite difficult for the tin industry. Tin consumption has been drastically reduced. ITC managed to avoid really big declines by accelerating purchases of its reserve holdings; This activity required the ITC to borrow heavily from banks and metal trading companies to increase its resources. ITC continued to borrow until late 1985, when it reached its credit limit. A major "tin crisis" immediately followed: tin was withdrawn from the London Metal Exchange for about 3 years, the ITC was dissolved soon after and the price of tin, now in a free market environment, plummeted sharply to US$4 per pound moved around this level in the 1990s.[39] It rose again in 2010 due to a recovery in consumption after the 2008-2009 global economic crisis, resupply and continued consumption growth in the world's developing countries.[] The London Metal Exchange (LME) is the leading trading venue for metals. Tin.[ ] Other markets for tin contracts are the Kuala Lumpur Tin Market (KLTM) and the Indonesian Tin Exchange (INATIN).[40]

Applications In 2006 about half of the tin produced was used for soldering. The remainder was divided between tinning chemicals, tin, brass, bronze and niche applications.[41]

World consumption of refined tin by end use, 2006

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Solder Tin has long been used as a solder in the form of an alloy with lead, with tin accounting for 5 to 70% by weight. Tin forms a eutectic mixture with lead, containing 63% tin and 37% lead. These solders are mainly used for soldering pipes or electrical circuits. Since the EU's Waste Electrical and Electronic Equipment (WEEE) Directive and Restriction of Hazardous Substances Directive came into force on July 1, 2006, the use of lead in such alloys has declined. Lead substitutes have many problems, including a higher melting point and the formation of tin filaments that cause electrical problems. Tin plague Lead-free solder wire can coil up on lead-free solder, resulting in loss of solder joints. Replacement alloys are being found quickly, although bond integrity issues remain.[42]

Tinning Tin adheres easily to iron and is used to coat lead or zinc and steel to prevent corrosion. Tinned steel containers are commonly used for food preservation and make up a large portion of the metallic tin market. A tin container for preserving food was first made in London in 1812.[43] British English speakers call them "cans", while American English speakers call them "cans" or "tin cans". Such usage derives from the slang "tinnie" or "tinny", meaning "beer can". The tin whistle is so named because it was the first to be mass-produced from tinned steel.[44][45]

specialized leagues

Tinplate

Tin in combination with other elements forms a variety of useful alloys. Tin is usually alloyed with copper. Tin contains 85–99% tin;[46] Babbitt is also rich in tin.[47][48] Bronze consists primarily of copper (12% tin), while the addition of phosphorus results in phosphor bronze. Bell metal is also an alloy of copper and tin containing 22% tin. Sometimes pewter was also used for coinage; for example, it has already made a single-digit percentage of US[49] and Canadian[50] cents. Since copper is often the main metal in such coins, and zinc is also sometimes present, they could technically be referred to as bronze and/or brass alloys. The niobium-tin-Nb3Sn compound is used commercially as wires for superconducting magnets due to the material's high critical temperature (18 K) and critical magnetic field (25 T). A superconducting magnet weighing only a few kilograms is capable of generating magnetic fields comparable to those produced by a conventional electromagnet weighing several tons.[] The addition of a small percentage of tin is commonly used in zirconium alloys for fuel plating.[51 ]

Most metal pipes in a pipe organ are made from varying amounts of a tin/lead alloy, with 50%/50% being the most common. The amount of tin in the tube determines the tuning of the tube since tin is the most resonant of all metals.

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148 statement. When an alloy of tin and lead is cooled, the lead will cool slightly faster, creating a tarnished or mottled effect. This metallic alloy is known as tarnished metal. The main advantages of using tin for tubing include its appearance, workability, and resistance to corrosion.[52][53]

Other applications Punched tin, also known as perforated tin, is a craft technique originating from Central Europe for the production of both functional and decorative household items. Decorative perforation designs come in a wide variety depending on geography or the personal creations of the craftsman. Cut tin lanterns are the most common use of this craft technique. Light from a candle shining through the perforated design creates a decorative light pattern in the room where it is placed. Perforated tin lanterns and other perforated pewter items have been made in the New World since the early European settlements. A well-known example is the Revere-type lantern, named after Paul Revere.[54] Before modern times, in some areas of the Alps, the horn of a goat or sheep was sharpened and a tin plate pierced with the alphabet and the numbers one through nine. This learning tool was aptly referred to as "the horn". Modern reproductions are decorated with motifs such as hearts and tulips.

A reproduction of a 21st century barn lantern

In the United States, cake and food safes were used before the perforated can. Cooling. These were wooden cabinets of various styles and sizes, standing or hanging, designed to keep vermin and insects out and to keep dust out of perishable foods. These cabinets had pewter hardware on the doors and sometimes on the sides, drilled in various designs by the owner, carpenter or hobbyist to allow air circulation. Modern reproductions of these items remain popular in North America.[55] Window glass is usually made by floating molten glass over molten tin (making float glass) to create a flat surface. This is called the "Pilkington process".[56] Tin is also used as the negative electrode in advanced lithium-ion batteries. Its application is somewhat limited by the fact that some tin surfaces catalyze the decomposition of carbonate-based electrolytes used in lithium-ion batteries.[57] Tin(II) fluoride is added to some dental products[58] as tin(II) fluoride (SnF2). Stannous fluoride can be mixed with calcium abrasives, while the more common sodium fluoride gradually becomes biologically inactive when combined with calcium compounds.[59] It has also been shown to be more effective than sodium fluoride in fighting gingivitis.[60]

Organotin compounds Of all the chemical compounds of tin, the organotin compounds are the most commonly used. World industrial production is expected to exceed 50,000 tons.[61] PVC Stabilizers The most important commercial application of organotin compounds is the stabilization of PVC plastics. Without such stabilizers, PVC would rapidly degrade under heat, light and atmospheric oxygen, resulting in brittle and discolored products. Tin removes labile chloride (Cl-) ions that would otherwise cause HCl loss from the plastic material.[] Typical tin compounds are those derived from the carboxylic acid of dibutyltin dichloride, such as B. dilaurate.[62]

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149 Biocidal organotin compounds can exhibit relatively high toxicity, which is beneficial and problematic. They have been used in/as fungicides, pesticides, algaecides, wood preservatives and antifouling agents for their biocidal activity.[] Tributyltin oxide is used as a wood preservative.[63] Tributyltin was used as an additive in marine paints to prevent the growth of marine organisms on ships, and its use declined after organotin compounds were identified as persistent organic pollutants with extremely high toxicity to some marine organisms, e.g. [64] The EU banned the use of organotin compounds in 2003,[65] due to concerns about the toxicity of these compounds to marine life and their effects on the reproduction and growth of some marine species[] (some reports describe biological effects on marine life in a concentration of 1 nanogram per liter) led to a worldwide ban by the International Maritime Organization.[66] Many nations now restrict the use of organotin compounds to containers longer than 25 meters.[] Organic Chemistry Some tin reagents are useful in organic chemistry. In its greatest application, tin chloride is a common reducing agent for converting nitro and oxime groups to amines. The Stille reaction couples organic tin compounds with organic halides or pseudohalides.[67] Li-Ion Batteries Tin forms several intermetallic phases with metallic lithium, making it a potentially attractive material. The large volumetric expansion of tin in combination with lithium and the instability of the tin-organic electrolyte interface at low electrochemical potentials are the main challenges when used in commercial cells. Sony has partially solved the problem. Sony implemented a tin-cobalt intermetallic compound mixed with carbon in its Nxelion cells released in the late 2000s. The composition of the active materials is close to Sn0.3Co0.4C0.3. Recent research has shown that only a few crystal faces of tetragonal (beta) Sn are responsible for the undesired electrochemical activity.[68]

Prevention Cases of poisoning by metallic tin, its oxides and its salts are "almost unknown". On the other hand, certain organotin compounds are almost as toxic as cyanide.[24]

Notes [3] Magnetic susceptibility of elements and inorganic compounds (http://www-d0.fnal.gov/hardware/cal/lvps_info/engineering/elementmagn.pdf), in [4] Tin nanoparticle ink can future plates Print Circuit (http://www.physorg.com/news/2011-04-ink-tin-nanoparticles-future-circuit.html), Physorg, April 12, 2011; [6] This transformation is known as tin disease or tin rot. Tin rot was a particular problem in northern Europe in the 18th century, as organ pipes made from tin alloy were sometimes affected during the long, cold winters. Some sources also say that during Napoleon's Russian campaign in 1812, temperatures were so cold that the pewter buttons on soldiers' uniforms disintegrated over time, contributing to the defeat of the Grande Armée. [9] Only H, F, P, Tl, and Xe are better suited for NMR analysis of samples containing isotopes in their natural abundance. [12] Oxford English Dictionary, 2nd edition, 1989. [13] Encyclopædia Britannica, 11th edition, 1911, s.v. 'Zinn' citing H. Kopp [15] American Heritage Dictionary [20] Inorganic and Theoretical Chemistry, F. Sherwood Taylor, Heineman, 6th edition (1942) [23] Elschenbroich, C. "Organometallics" (2006) Wiley -VCH : Weinheim. ISBN 978-3-527-29390-2 [24] Graf, G. G. (2000) "Tin, Tin Alloys and Tin Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, 2005 Wiley-VCH, Weinheim [39] Carlin, James F., Jr (1998). Significant events affecting tin prices since 1958 (http://minerais.usgs.gov/minerais/pubs/commodities/tin/660798.pdf). USGS.

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References Bibliography •

• •

• • •

This article incorporates text from a publication now in the public domain: Carlin, James F., Jr. (1998). "Significant Events Affecting Tin Prices Since 1958" (http://minerals.usgs.gov/minerals/pubs/commodity/tin/660798.pdf). United States National Geodetic Survey CRC contributors (2006). David R. Lide (editor), ed. Handbook of Chemistry and Physics (87th ed.). Boca Raton, Florida: CRC Press, Taylor & Francis Group. ISBN0-8493-0487-3. Emsley, John (2001). "Tin" (http://books.google.com/?id=j-Xu07p3cKwC&printsec=frontcover). The Building Blocks of Nature: An A to Z Guide to the Elements. Oxford, England, UK: Oxford University Press. pp. 445-450. ISBN0-19-850340-7. Greenwood, N.N.; Earnshaw, A. (1997). Chemistry of the Elements (2nd ed.). Oxford: Butterworth-Heinemann. ISBN0-7506-3365-4. Heisermann, David L. (1992). "Item 50: tin." Research into chemical elements and their compounds. New York: TAB Books. ISBN0-8306-3018-X. Macintosh, Robert M. (1968). "Tin". In Clifford A. Hampel (editor). The Encyclopedia of the Chemical Elements. New York: Reinhold Book Corporation. pp. 722-732. LCCN 68-29938 (http://lccn.loc.gov/68-29938).

• Stwertka, Albert (1998). "Tin". Guide to the Elements (Revised Edition). Oxford University Press. ISBN0-19-508083-1.

External Links • Tin (http://www.periodicvideos.com/videos/050.htm) at The Periodic Table of Videos (University of Nottingham) • Theodore Gray's Wooden Periodic Table (http://www.theodoregray.com/ ) Periodic Table/Elements/050/ index.s7.html): Tin samples and castings • Base metals: Tin (http://www.basemetals.com/html/sninfo.htm)

welding

WARNING: Unable to process item; Plain text is generated. Possible causes of the problem are: (a) a bug in the PDF writing software (b) problematic Mediawiki markup (c) the table is too wide A solder joint used to connect a wire to a component pin on the back of the PCB to connect the shield. Solder (/ˈsoʊldə/, /ˈsɒldə/ or sometimes in the US /ˈsɒdər/Oxford American Dictionary) is a fusible metal alloy used to join metal parts that has a melting point lower than the part(s). Soldering is usually considered when mentioning soldering or brazing, with a typical melting range of 90 to 450 °C (190 to 840 °F). Frank Oberg, Franklin D. Jones, Holbrook L. Horton, Henry H. Ryffel (eds.) Machinery's Handbook 23rd Edition Industrial Press Inc., 1988, ISBN 0-8311-1200-X, page 1203 Assembly of sheet metal parts. Hand soldering uses a soldering iron or soldering gun. Alloys that melt between 180 and 190 °C (360 and 370 °F) are most commonly used. Soldering with alloys with a melting point greater than 840°F (450°C) is referred to as "brand soldering", "silver soldering" or brazing. At certain ratios, an alloy becomes eutectic and melts at a single temperature; Non-eutectic alloys have significantly different solidus and liquidus (chemical) temperatures and exist within this range as a slurry of solid particles in a lower melt phase melt. In electrical work, if the connection is disturbed in a pasty state before it is fully solidified, it may result in poor electrical connection; the use of eutectic solder reduces this problem. The pasty state of a non-eutectic solder can be used in plumbing as it allows the solder to be shaped as it cools, e.g. to ensure the tightness of pipe joints, resulting in the so-called "clean joint". Solder wire is available in various gauges for hand soldering and fluxed (metallurgy) flux for electrical and electronic work. It is also available as a paste or as a pre-formed sheet to suit the workpiece, best suited for mechanized mass production. Lead and tin alloys were universally used in the past and are still available; they are particularly suitable for hand soldering. Lead-free solder, which is a little less convenient to solder by hand, is widely used to avoid the environmental impact of lead. Plumbers often use soldering irons that are much thicker than the wire used for electrical applications. Jewelers often use thin sheets of solder that they cut into pieces. The word solder comes from Middle English soudur, via Old French solduree, and soulder, from Latin solidare, meaning to make firm. As the size of the circuit board features is reduced, the size of the interconnects is also reduced. Current densities in excess of 104 A/cm2 are often achieved and electromigration becomes a problem. At such current densities, the Sn63Pb37 solder bumps form bumps on the anode side and voids on the cathode side; the higher lead content on the anode side indicates that lead is the main migratory species. Contact with molten solder can cause material "weld embrittlement", a type of liquid metal embrittlement. They are commercially available as so-called solders with tin concentrations of between 5 and 70% by weight. The higher the tin concentration, the higher the tensile and shear strength of the solder. Alloys commonly used for electrical soldering are 60/40 tin/lead (Sn/Pb), which melts at 370°F or 188°C, and 63/37 Sn/Pb, which is primarily used in electrical/electronic work will. 63/37 is a eutectic point alloy that: has the lowest melting point (183°C or 361.4°F) of any tin/lead alloy; and the melting point is really a point, not a range. A higher proportion of lead was used in plumbing, typically 50/50. The advantage of this was that the alloy solidified more slowly, so it could be rubbed over the joint to ensure tightness and the tubes physically joined before welding. Although lead-containing water pipes were replaced by copper as the importance of lead poisoning began to be fully appreciated, lead solder continued to be used well into the 1980's because it was believed that the amount of lead that could get into solder water was negligible be suitable place, put. soldier

151

Solder Joint The electrochemical couple of copper and lead promotes corrosion of lead and tin, but tin is protected by insoluble oxides. Since even small amounts of lead were considered unhealthy, lead in sanitary solder was replaced by silver (food applications) or antimony, copper was often added and the tin content was increased (see #free soldering soda). The addition of tin, more expensive than lead, improves the alloy's wetting properties; Lead itself has poor wetting properties. High tin lead-tin alloys are of limited use because the machinability range can be provided by a cheaper high lead alloy. welded joints. Solder paste has largely replaced solid solder in miniaturized circuit board connections with surface mount components. Lead and tin solders readily dissolve gold plating and form brittle intermetallic compounds. Sn60Pb40 solder oxidizes on the surface and forms a complex 4-layer structure: tin(IV) oxide on the surface, below a tin(II) oxide layer with finely dispersed lead, followed by a tin(II) oxide layer with finely divided tin and lead and the solder itself underneath. Radioisotopes that undergo alpha decay are of concern because they tend to introduce small errors. Polonium-210 is particularly problematic; Beta lead-210 decays to bismuth-210, which beta then decays to polonium-210, a powerful emitter of alpha particles. Uranium-238 and Thorium-232 are other significant impurities in lead alloys. ) and the Restriction of Hazardous Substances Directive (RoHS) came into effect, banning the intentional addition of lead to most consumer electronics manufactured in the EU. US manufacturers can obtain tax benefits by reducing the use of lead-based solder. Commercial lead-free solders can contain tin, copper, silver, bismuth, indium, zinc, antimony, and traces of other metals. Most lead-free substitutes for conventional Sn60/Pb40 and Sn63/Pb37 solders have melting points that are 5 to 20 °C higher, Ganesan and Pecht p. 110, although there are solders with much lower melting points. Direct replacement for screen printing with solder paste operations is available. Minor modifications to solder pots (eg, titanium coatings or sliders) used in wave soldering operations may be desirable to reduce maintenance costs associated with increased detinning effects of high-tin solders. Because the properties of lead-free solders are not well known, they may be considered less desirable for critical applications such as certain aerospace or medical projects. "Tin (metallurgical) whiskers" were a problem with early electronic solders, and lead was initially partially added to the alloy to eliminate them. Sn-Ag-Cu (tin-silver-copper) solders are used by two-thirds of Japanese manufacturers for reflow and wave soldering and about 75% of companies for hand soldering. The widespread use of this popular family of lead-free solder alloys is due to the low melting point of the Sn-Ag-Cu ternary eutectic (217˚C), which is lower than that of Sn-3.5Ag (wt%). eutectic. ) of 221°C and the eutectic Sn-0.7Cu of 227°C (recently changed to Sn-0.9Cu by P. Snugovsky). The ternary eutectic behavior of Sn-Ag-Cu and its application in electronic component assembly was discovered (and patented) by a research team from Iowa State University's Ames Laboratory and Sandia National Laboratories in Albuquerque. Much of the recent research has focused on the selection of fourth element additions to Sn-Ag-Cu to ensure compatibility with the reduced cooling rate of solder bump reflow for mounting ball grid arrays, e.g. Sn-3, 5Ag-0.74Cu-0.21Zn (melting range 217-220˚C) and Sn-3.5Ag-0.85Cu-0.10Mn (melting range 211-215˚C). Tin-based solders readily dissolve gold and form brittle intermetallic compounds; For Sn-Pb alloys, the critical gold concentration to weaken the bond is around 4%. Indium-rich solders (generally indium-lead) are best for soldering thicker layers of gold, as the rate of dissolution of gold in indium is much slower. Tin-rich solders also readily dissolve silver; Alloys with added silver are suitable for soldering metallization or silver surfaces; Tin-free alloys are also possible, but with lower wettability. If the soldering time is long enough to form intermetallics, the tin finish of a gold joint will be too dull. Flux-Cored Solder Electrical solder with an embedded resin core, visible as a dark spot on the cut end of the solder wire. Flux (Metallurgy) Flux is a reducing agent designed to aid in redox reduction (returning oxidized metals to their normal state). metallic) metal oxides at contact points to improve the electrical connection and mechanical strength. The two main types of flux are acid fluxes, used for metal and plumbing repairs, and rosin fluxes, used in electronics where the corrosiveness of acid fluxes and

152

Solder fumes released when the solder heats up can damage sensitive circuits. Due to concerns about air pollution and hazardous waste disposal, the electronics industry has gradually transitioned from rosin fluxes to water-soluble fluxes that can be removed with deionized water and detergents rather than hydrocarbon solvents. As opposed to using traditional all-metal soldering rods or coiled wire and manually applying flux to the parts to be joined, many hand solderers have used flux cored solder since the mid-20th century. This is manufactured as a coiled solder wire in which one or more continuous, non-acidic flux bodies are embedded lengthwise. As the solder melts into the joint, it releases and releases the flux as well. Brazing alloys Brazing alloys are used for soldering and melting at higher temperatures. The most common are copper alloys with zinc or silver. Special hard solders that pass the metallurgical test are used in cutlery and jewellery. They contain a high proportion of the soldered metal and lead is not used in these alloys. These welds vary in hardness and are referred to as "glazed", "hard", "medium" and "light". Vitreous Enamel Enamel solder has a high melting point, close to that of the material itself, to prevent unsoldering of the joint during firing in the enameling process. The remaining types of solder are used during the manufacturing process of an item in order of decreasing hardness to prevent a previously soldered seam or joint from being desoldered while additional locations are being soldered. For the same reason, light soldering is also popular for repair work. Jeweler's flux or blush is also used to keep the compounds from unraveling. Silver solder is also used in manufacturing to join metal parts that cannot be soldered. Alloys used for these purposes contain a high percentage of silver (up to 40%) and may also contain cadmium. Composition of the solder alloys Melting point M.P. °CSolid (Chemical)S/LiquidL Eutectic Toxic Remarks Sn Pb Ag Cu Sb Bi In Zn Cd Au oth. ! Sn50Zn49Cu1 200/300 Galvanite Free Lead free electroplating solder specially developed for high quality repairs on galvanized steel surfaces. Simple, efficient and user-friendly in both manufacturing and field applications. Metallurgically bonds to steel to form a continuous protective barrier. 50 1 49 Sn90Zn7Cu3 200/222 no Kapp Eco-Babbitt Commonly used in capacitor manufacture as a protective coating to protect against Electromotive Force (EMF) and Electromagnetic Interference (EMI) with specified capacitor performance to prevent current leakage and charging from and within the capacitor Capacitor layers and to prevent the development of electron flows within the plating material itself, which would reduce capacitor performance, plating and capacitor life. 90 3 7 Pb90Sn10 268/302 275/302 Pb Non-Sn10 Alloy Information, UNS L54520, ASTM10B. Balls for ceramic ball grid array CBGA components replaced by Sn95.5Ag3.9Cu0.6. Low cost and good adhesive properties. Dissolves gold and silver quickly, not recommended for them. It is used in the manufacture of car radiators (engine cooling), radiators and fuel tanks, for coating and bonding metals for medium operating temperatures. body sweating. ALLOY TABLE FOR BRAZE. (PDF). Accessed on 06/07/2010. It has low thermal emf, can be used as an alternative to Cd70 when thermocouple stray voltages need to be avoided. 296 Pb not Used in the manufacture of car radiators and fuel tanks, for coating and joining metals for moderate service temperatures. body sweating. 12 88 Pb85Sn15 227/288 Pb no It is used in the coating of pipes and plates and in the manufacture of car radiators. body sweating. 15 85 Pb80Sn20 183/280 Pb without Sn20, UNS L54711. It is used to cover the radiator tubes to connect the fins. 20 80 Pb75Sn25 183/266 Pb no Solder blank for construction plumbing, flame cast. It is used for welding radiators for car engines. It is used for machine, immersion and manual welding of plumbing fixtures and fittings. Welded seam on the upper body. 25 75 Pb70Sn30 185/255 183/257 Pb Non Sn30, UNS L54280 Coarse filler metal for construction pipe, flame casting, good for machine and torch brazing. It is used for welding radiators for car engines. It is used for machine, immersion and manual welding of plumbing fixtures and fittings. Welded seam on the upper body. 30 70 Pb68Sn32 253 Pb in Plumbing Solder, for Construction Plumbing 32 68 Pb68Sn30Sb2 185/243 Pb in Pb68 30 68 2 Sn30Pb50Zn20 177/288 Pb in Kapp GalvRepair Economical solder for repairing and joining most metals including aluminum and cast iron. They were used to repair cast iron and galvanized surfaces. 30 50 20 Sn33Pb40Zn28 230/275 Pb no Economical solder for repairing and joining most metals including aluminum and cast iron. They were used to repair cast iron and galvanized surfaces. 33 40 28 Pb67Sn33 187-230 Pb in PM 33, brazing filler metal for construction plumbing, flame casting, temperature dependent additives 33 67 Pb65Sn35 183/250 Pb in Sn35. It is used as a cheaper alternative to Sn60Pb40 for cleaning and sweating joints. 35 65 Sc60Sn40 183/238 183/247 Sc no

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Lot Sn40, UNS L54915. For soldering brass and car radiators. For bulk solder and where a wider melting point range is desired. For connecting cables. For cleaning and connecting lead pipes. For repairs to radiators and electrical systems. 40 60 Pb55Sn45 183/227 Pb no For welding radiator cores, ceiling joints and decorative joints. 45 55 Sn50Pb50 183/216 183-212 Sb without Sn50, UNS L55030. "Ordinary soldering", for soldering brass, electricity meters, gas meters, formerly also cans. Universally applicable, for standard sheet metal and sheet metal work. Below -150°C it becomes brittle. Low cost and good adhesive properties. Dissolves gold and silver quickly, not recommended for them. For cleaning and assembling pipe connections for non-potable water. 50 50 Sn50Pb48.5Cu1.5 183/215 3439-00-577-7594 Solder, tin alloy. tpub. with. Accessed on 06/07/2010. Pb in Savbit, Savbit1, Sav1. Minimizes copper dissolution. Originally developed to reduce soldering iron tip erosion. Copper erodes about 100 times slower than traditional tin and lead alloys. Suitable for soldering thin copper sheets and very thin copper wires. msl747.PDF. (PDF). Accessed on 06/07/2010. 50 48.5 1.5 Sn60Pb40 183/190 183/188 Pb similar to Sn60, ASTM60A, ASTM60B. Common in electronics, the most popular lead alloy for immersion. Low cost and good adhesive properties. It is used in both SMT electronics and through hole electronics. Dissolves gold and silver quickly, not recommended for them. Slightly cheaper than Sn63Pb37, it is often used for cost reasons, since the melting point difference is negligible in practice. On slow cooling it gives slightly more opaque compounds than Sn63Pb37. 60 40 Sn60Pb38Cu2 183/190 Pajky_vkladanylist_Cze_ang_2010.indd. (PDF). Accessed on 06/07/2010. PbCu2. The copper content increases the hardness of the alloy and prevents soldering iron tips and strands from dissolving in molten solder. 60 38 2 Sn60Pb39Cu1 Pb no 60 39 1 Sn62Pb38 183 Pb near "tin solder" used for tinplate manufacture. 62 38 Sn63Pb37 182 183 Balver Zinn Solder Sn63Pb37 Pb yes Sn63, ASTM63A, ASTM63B. Common in electronics; excellent tinning and wetting properties, also good for stainless steel. One of the most common solders. Low cost and good adhesive properties. It is used in both SMT electronics and through hole electronics. Dissolves gold and silver quickly, not recommended for them. Sn60Pb40 is slightly cheaper and is often used for cost reasons, since the melting point difference is negligible in practice. With slow cooling it gives slightly brighter transitions than Sn60Pb40. 63 37 Sn63Pb37P0.0015–0.04 183 Balver Tin Solder Sn63PbP Pb Yes Sn63PbP. A special alloy for HASL machines. The addition of phosphorus reduces oxidation. Not suitable for wave soldering as metal foaming is possible. 63 37 P Sn62Pb37Cu1 183 Pb yes Similar to Sn63Pb37. The copper content increases the hardness of the alloy and prevents soldering iron tips and strands from dissolving in molten solder. 62 37 1 Sn70Pb30 183/193 Pb not Sn70 70 30 Sn90Pb10 183/213 Pb not previously used for joints in the food industry 90 10 Sn95Pb5 238 Pb without plumbing and heating 95 5 Pb92Sn5.5Ag2.5 286/301 Pb no For higher temperatures high Applications 5.5 92 2.5 Pb80Sn12Sb8 Pb no Used for welding iron and steel 12 80 8 Pb80Sn18Ag2 252/260 Pb no Used for welding iron and steel 18 80 2 Pb79Sn20Sb1 184/270 Pb not Sb1 20 79 1 Pb55Sn43 , 5Sb1 no universal welding 5.5 scp . Antimony content improves mechanical properties but causes brittleness when welding cadmium, zinc or galvanized metals. 43.5 55 1.5 Sn43Pb43Bi14 144/163 bp without Bi14. Good fatigue strength combined with low melting point. Contains tin and lead bismuth phases. Useful for step welding. 43 43 14 Sn46Pb46Bi8 120/167 bp no Bi8 46 46 8 Bi52Pb32Sn16 96 bp yes? Bi52. Good fatigue strength combined with low melting point. Adequate shear strength and fatigue properties. Combination with tin-lead solder can drastically lower the melting point and cause joint failure. 16 32 52 Bi46Sn34Pb20 100/105 bp no Bi46 34 20 46 Sn62Pb36Ag2 179 bp yes Sn62. Common in electronics. The strongest tin-lead solder. Identical appearance as Sn60Pb40 or Sn63Pb37. Ag3Sn crystals grow out of the solder. Prolonged heat treatment leads to the formation of binary alloy crystals. The silver content reduces the solubility of silver, making the alloy suitable for soldering silver-plated surfaces, e.g. SMD capacitors and other silver ceramics. Not recommended for gold. general purpose. 62 36 2 Sn62.5Pb36Ag2.5 179 Pb yes 62.5 36 2.5 Pb88Sn10Ag2 268/290 267/299 Indalloy 228 Pb-Sn-Ag Alloy Solder Pb on Sn10, Pb88. The silver content reduces the solubility of silver coatings in solder. Not recommended for gold. Forms a eutectic phase, not recommended for service above 120°C. 10 88 2 Pb90Sn5Ag5 292 Pb yes 5 90 5 Pb92.5Sn5Ag2.5 287/296 299/304 Pb no Pb93. 5 92.5 2.5 Pb93.5Sn5Ag1.5 296/301 305/306 Pb not Pb94, binds HMP, HMP. Operating temperatures up to 255 °C. Useful for step welding. It can also be used at extremely low temperatures as it remains ductile down to -200°C, while solders with more than 20% tin become brittle below -70°C. greater power and

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Solder better wetting than Pb95Sn5. 5 93.5 1.5 Pb95.5Sn2Ag2.5 299/304 Pb no 2 95.5 2.5 In97Ag3 143 Indium Corp. Indalloy Braze Alloy 290 In-Ag – Yes Indium wettability and low temperature formability, strength enhanced by addition of silver. Especially good for cryogenic applications. It is used to package photonic devices. 3 97 In90Ag10 143/237 Indalloy 3 In-Ag solder alloy – no Almost as wettable and ductile as indium at low temperatures. Large selection of plastic. It can weld silver, fired glass and ceramics. 10 90 In75Pb25 156/165 Pb no Less soluble in gold and more ductile than lead-tin alloys. It is used for fixing dies, assembling general circuits and sealing packages. 25 75 In70Pb30 160/174 165/175 Indalloy 204 In-Pb Solder Alloy Pb not In70. Suitable for gold, low gold leach. Good thermal fatigue properties. 30 70 In60Pb40 174/185 173/181 Pb not In60. Low Gold Leach. Good thermal fatigue properties. 40 60 In50Pb50 180/209 178/210 Pb not In50. Just a phase. Soldering with tin-lead solder forms the indium-tin and indium-lead phases and leads to interphase cracking, weakening of the joints and failure. Indium-gold intermetallics tend to form on the gold surfaces and then the connection fails in the gold-depleted zone and the gold-rich intermetallic. Less gold dissolution and more ductile than lead-tin alloys. Good thermal fatigue properties. 50 50 In50Sn50 118/125 Indalloy 1 Indium Tin Solder Alloy - Cerroseal Free 35. Wets glass, quartz and many ceramics reasonably well. Malleable, can accommodate some differences in thermal expansion. Low vapor pressure. It is used in low-temperature physics as a glass-wetting solder. 50 50 In70Sn15Pb9.6Cd5.4 125 Indalloy 13 Indium Pb Solder,Cd 15 9.6 70 5.4 Pb75In25 250/264 240/260 Indalloy 10 Pb-In Pb Solder Non-In25. Low Gold Leach. Good thermal fatigue properties. It is used to fix arrays of e.g. GaAs dies. It is also used to assemble circuits in general and to seal containers. Less gold dissolution and more ductile than tin-lead alloy. 75 25 Sn70Pb18In12 162154/167 Indalloy 9 Sn-Pb-In Solder Pb alloy yes general purpose. Good physical properties. 70 18 12 Sn37.5Pb37.5In25 134/181 Pb no Good wettability. Not recommended for gold. 37.5 37.5 25 Pb90In5Ag5 290/310 Pb at 90 5 5 Pb92.5In5Ag2.5 300/310 Pb at UNS L51510. Minimal gold leaching, good thermal fatigue properties. Reduced atmosphere with frequent use. UNS L50180 Pb No. Ag5.5, UNS L50180 94.5 5.5 Pb95Ag5 305/364 Indalloy 175 Lead Solder Alloy Pb No. 95 5 Pb97.5Ag2.5 303 304 304/579 97.5Pb-2.5Ag Lead Silver solder, class ASTM 2.5S UNS L50132 Pb otherwise Ag2.5, UNS L50132. Used during WWII to preserve pewter. Low corrosion resistance; Seals that corroded under atmospheric and subsurface conditions all had to be replaced with Sn-Pb alloy seals. Welding with a torch. 97.5 2.5 Sn97.5Pb1Ag1.5 305 Pb si Important for the construction of hybrid circuits. 97.5 1 1.5 Pb97.5Ag1.5Sn1 309 Pb se Ag1.5, ASTM1.5S. High melting point, used for commutators, armatures and first solder joints where melting is not desired when working closely. Silver content reduces the solubility of silver coatings in molten solder. Not recommended for gold. PbAgSn standard eutectic solder widely used in semiconductor assembly. Reducing protective atmosphere (e.g. 12% hydrogen) is often used. High creep resistance, for use at elevated and cryogenic temperatures. 1 97.5 1.5 Pb54Sn45Ag1 177-210 Pb Exceptional strength, silver provides a bright, durable finish; ideal for stainless steel 45 54 1 Pb96Ag4 305 Pb high temperature joints 96 4 Pb96Sn2Ag2 252/295 Pb Pb96 2 96 2 Sn61Pb36Ag3 Pb 61 36 3 Sn56Pb39Ag5 Pb 56 39 5 Sn98Ag2 – 98 2 –Sn39 High strength. Motorola matrix mounting solder very fragile. 65 25 10 Sn96.5Ag3.0Cu0.5 217/220 217/218 Balver Zinn Weld SN97C (SnAg3.0Cu0.5) – next to SAC305. It is JEITA's recommended alloy for wave and reflow soldering, with alternatives SnCu for wave soldering and SnAg and SnZnBi for reflow soldering. Can also be used for selective soldering and dip soldering. At high temperatures it tends to dissolve copper; Accumulations of copper in the bath have a detrimental effect (e.g. enlarged bridges). The copper content should be kept between 0.4 and 0.85%, e.g. Filling the bath with Sn97Ag3 alloy. Nitrogen atmosphere can be used to reduce slag losses. The opaque surface shows the formation of dendritic tin crystals. 96.5 3 0.5 Sn95.8Ag3.5Cu0.7 217–218 – similar to SN96C-Ag3.5 A commonly used alloy. It is used for wave soldering. Can also be used for selective soldering and dip soldering. At high temperatures it tends to dissolve copper; Accumulations of copper in the bath have a detrimental effect (e.g. enlarged bridges). The copper content should be kept between 0.4 and 0.85%, e.g. Fill the bath with the alloy Sn96.5Ag3.5 (referred to as SN96Ce for example). Nitrogen atmosphere can be used to reduce slag losses. The opaque surface shows the formation of dendritic tin crystals. 95.8 3.5 0.7 Sn95.6Ag3.5Cu0.9 217 - yes Determined by NIST to be a true eutectic. 95.6 3.5 0.9 Sn95.5Ag3.8Cu0.7

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Lot 217 Balver Zinn Solder SN96C (SnAg3.8Cu0.7) – almost SN96C. Preferred by the European IDEALS consortium for reflow soldering. Can also be used for selective soldering and dip soldering. At high temperatures it tends to dissolve copper; Accumulations of copper in the bath have a detrimental effect (e.g. enlarged bridges). The copper content should be kept between 0.4 and 0.85%, e.g. Fill the bath with a Sn96.2Ag3.8 alloy (designated as SN96Ce for example). Nitrogen atmosphere can be used to reduce slag losses. The opaque surface shows the formation of dendritic tin crystals. 95.5 3.8 0.7 Sn95.25Ag3.8Cu0.7Sb0.25: preferred by the European IDEALS consortium for wave soldering. 95.25 3.8 0.7 0.25 Sn95.5Ag3.9Cu0.6 217 Indalloy 252 95.5Sn/3.9Ag/0.6Cu Lead-free solder alloy: Yes Recommended by US NEMI Consortium for reflow soldering. Used as balls for Ball Grid ArrayBGA/Chip Scale PackageCSP and CBGA components, a replacement for Sn10Pb90. Solder paste for reworking BGA boards. Alloy of choice for general SMT assembly. 95.5 3.9 0.6 Sn95.5Ag4Cu0.5 217 Indalloy 246 95.5Sn/4.0Ag/0.5Cu Lead Free Solder Alloy - Yes Lead and cadmium free formulation specially formulated to weld lead solder in copper and To replace stainless steel and in electrical and electronic applications 95.5 4 0.5 Sn96.5Ag3.5 221 – yes Sn96, Sn96.5, 96S. Fine lamellar structure of densely distributed Ag3Sn. Annealing at 125°C thickens the structure and softens the solder. It sneaks through the rise in discord as a result of network diffusion. Used as rework wire in hand soldering; compatible with SnCu0.7, SnAg3Cu0.5, SnAg3.9Cu0.6 and similar alloys. Used as a solder ball for BGA/CSP components. It is used for staggered soldering and chip fixing in high power devices. Consolidated history in the industry. Widespread. Strong lead-free compounds The silver content minimizes the solubility of silver coatings. Not recommended for gold. edge wetting. Good for step welding. It is used for welding stainless steel because it wets stainless steel better than other soft welds. The silver content does not suppress the dissolution of silver metallization. The high tin content allows it to hold a significant amount of gold without embrittlement. Solder selection for Photonic Packing 96.5 3.5 Sn96Ag4 221-229 - without ASTM96TS. "Silver Lot". Equipment for gastronomy, cooling, heating, air conditioning, sanitary. Widespread. Strong lead-free compounds The silver content minimizes the solubility of silver coatings. Not recommended for gold. 96 4 Sn95Ag5 221/254 – no Widespread. Strong lead-free compounds The silver content minimizes the solubility of silver coatings. Not recommended for gold. Creates strong, ductile joints in copper and stainless steel. The resulting joints have a high tolerance to vibration and stress with tensile strengths up to 30,000 psi in stainless steel. 95 5 Sn94Ag6 221/279 – no Creates strong, ductile joints in copper and stainless steel. The resulting joints have a high tolerance to vibration and stress with tensile strengths up to 30,000 psi in stainless steel. 94 6 Sn93Ag7 221/302 – no Creates strong, ductile joints in copper and stainless steel. The resulting connections have a high tolerance to vibration and stress with tensile strengths up to 31,000 psi in stainless steel. Audio industry standard for vehicle and home theater speaker installations. Its 7% silver content requires a higher temperature range but produces superior strength and vibration resistance. 93 7 Sn95Ag4Cu1 – 95 4 1 Sn 232 – Pure Sn99. Good durability, does not dull. Used in food processing equipment, tinning of wire and alloys. Vulnerable to tin rot. 99.99 Sn99.3Cu0.7 227 – yes Sn99Cu1. Also referred to as Sn99Cu1. Economical alternative to wave soldering, recommended by the American company NEMI. Coarse microstructure with ductile fractures. Thinly distributed Cu6Sn5. Ganesan and Pecht p. 404 It forms large dendritic ß-tin crystals in a eutectic network with finely distributed Cu6Sn5. High melting point unfavorable for SMT use. Low strength, high ductility. Vulnerable to tin rot. The addition of a small amount of nickel increases fluidity; the largest increase occurs at 0.06% Ni. These alloys are known as nickel modified or nickel stabilized. Flux of lead-free Sn-Cu eutectic solder modified with Ni 99.3 0.7 (Ni) Sn99Cu0.7Ag0.3 217/228 Balver Zinn SCA solder (SnCu0.7Ag0.3) - without SCA, SAC or SnAgCu. Tin-silver-copper alloy. Relatively inexpensive lead-free alloy for simple applications. It can be used for wave, selective and dip soldering. At high temperatures it tends to dissolve copper; Accumulations of copper in the bath have a detrimental effect (e.g. enlarged bridges). The copper content should be kept between 0.4 and 0.85%, e.g. Fill the bath with a Sn96.2Ag3.8 alloy (designated as SN96Ce for example). Nitrogen atmosphere can be used to reduce slag losses. The opaque surface shows the formation of dendritic tin crystals. 99 0.3 0.7 Sn97Cu3 227/250 Balver Zinn Solder Sn97Cu3 232/332 – For use at high temperatures. Allows stripping insulation from an enameled wire and applying a layer of solder in a single operation. For repairs to radiators, stained glass and drinking water pipes. 97 3 Sn97Cu2.75Ag0.25 228/314 – High hardness, heat resistant. For radiators, stained glass and drinking water

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Weld water pipe. Excellent high strength solder for radiator repairs. Large selection of patinas and colors. 97 0.25 2.75 Zn100 419 – pure For welding aluminium. Good aluminum wettability, relatively good corrosion resistance. 100 Bi100 271 - pure Used as a non-superconducting solder in low temperature physics. Does not wet metals well, forms a mechanically weak bond. 100 Sn91Zn9 199 – yes KappAloy9 Specially developed for welding aluminum to aluminum and aluminum to copper. It has good corrosion resistance and tensile strength. It sits between soft solder and silver solder alloys, preventing damage to critical electronics and substrate warping and segregation. Best solder for aluminum wire to copper bars or copper wire to aluminum bars or contacts. UNS#: L91090 91 9 Sn85Zn15 199/260 – without KappAloy15 Specially developed for welding aluminum to aluminum and aluminum to copper. It has good corrosion resistance and tensile strength. It sits between soft solder and silver solder alloys, preventing damage to critical electronics and substrate warping and segregation. It has a wide range of plastics ideal for manual welding of aluminum plates and parts, allowing manipulation of the parts as the weld cools. 85 15 Zn95Al5 382 – yes For welding aluminium. Good hydration. 95 Al5 Sn91.8Bi4.8Ag3.4 211/213 Indalloy 249 91.8Sn/3.4Ag/4.8Bi Lead Free Solder Alloy - No Do not use on leaded metallizations. US Patent 5,439,639 (Sandia patent licensed by ICA). 91.8 3.4 4.8 Sn70Zn30 199/316 – without KappAloy30 For welding aluminium. Good hydration. Widely used in the form of powdered wire for capacitors and other electronic parts. Higher temperature and higher tensile strength compared to 85Sn/15Zn and 91Sn/9Zn. 70 30 Sn80Zn20 199/288 – without KappAloy20 For welding aluminium. Good hydration. Widely used in the form of powdered wire for capacitors and other electronic parts. Higher temperature and higher tensile strength compared to 85Sn/15Zn and 91Sn/9Zn. 80 20 Sn60Zn40 199/343 – no KappAloy40 For welding aluminium. Good hydration. Widely used in the form of powdered wire for capacitors and other electronic parts. Higher temperature and higher tensile strength compared to 85Sn/15Zn and 91Sn/9Zn. 60 40 Pb63Sn35Sb2 185/243 Pb no Sb2 35 63 2 Pb63Sn34Zn3 170/256 Pb no Poor wettability of aluminium. Low corrosion rate. 34 63 3 Pb92Cd8 310? Lead CD? For welding aluminum. U.S. Patent 1,333,666. Composition and physical properties of alloys. Csudh.edu (2007-08-18). Accessed on 06/07/2010. 92 8 Sn48Bi32Pb20 140/160 Pb no For low-temperature welding of heat-sensitive parts and for welding close to weld seams without post-melting. 48 20 32 Sn89Zn8Bi3 191–198 – Prone to corrosion and oxidation due to zinc content. On copper surfaces it forms a brittle Cu-Zn intermetallic layer that reduces the fatigue strength of the joint; the copper-nickel plating prevents this. 89 3 8 Sn83.6Zn7.6In8.8 181/187 Indalloy 226 Tin Solder Alloy: No high dross through zinc. Protected by US Patent No. 5,242,658. 83.6 8.8 7.6 Sn86.5Zn5.5In4.5Bi3.5 174/186 Indalloy Solder Alloy 231 Sn-Zn-In-Bi - Lead Free. Corrosion problems and high dross formation due to zinc content. 86.5 3.5 4.5 5.5 Sn86.9In10Ag3.1 204/205 Indalloy 254 86.9Sn/10.0In/3.1Ag Lead-free solder alloy: Possible use in flip chip assembly, no problems with the eutectic tin-indium phase. 86.9 3.1 10 Sn95Ag3.5Zn1Cu0.5 221L - no 95 3.5 0.5 1 Sn95Sb5 235/240 232/240 - no Sb5, ASTM95TA. The US standard for the plumbing industry features good resistance to thermal fatigue and good shear strength. It forms thick dendrites from tin-rich solid solution with intermetallic SbSn dispersed in between. Ductility at very high ambient temperature. It is entrained by viscous sliding of diffusional dislocations in the pipe. More creep resistant than SnAg3.5. Antimony can be toxic. Used for sealing chip packages, connecting I/O pins to ceramic substrates, and chip bonding; a possible replacement for AuSn at lower temperature. High strength and glossy surface. Used in air conditioning, refrigeration, some food containers and high temperature applications. Good wettability, good long-term shear strength at 100°C. Suitable for drinking water systems. It is used for stained glass, plumbing and radiator repairs. 95 5 Sn97Sb3 232/238 Indalloy 131 97Sn/3Sb Lead Free Solder – No 97 3 Sn99Sb1 232/235 Indalloy 129 99Sn/1Sb Lead Free Solder – No 99 1 Sn99Ag0.3Cu0.7 – 99 0.3 0.7 Sn29 .2Sb0g .5 .2Sb0g .81Cu0g – 225 217 - Ag03A. Patented by the AIM Alliance. 96.2 2.5 0.8 0.5 Sn88In8.0Ag3.5Bi0.5 197-208: Patented by Panasonic Corporation Matsushita/Panasonic. 88 3.5 0.5 8 Bi57Sn42Ag1 137/139 139/140 Indalloy 282 57Bi/42Sn/1Ag Lead-free solder alloy: The addition of silver improves mechanical strength. Established usage history. Good thermal fatigue behavior. Patented by Motorola. 42 1 57 Bi58Sn42 138 – yes Bi58. Adequate shear strength and fatigue properties. Combination with tin-lead solder can drastically lower the melting point and cause joint failure. Eutectic low temperature solder with high strength. Particularly strong, very brittle. widespread in

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Solder through-hole assemblies on IBM mainframe computers that required low-temperature soldering. Can be used as a coating for copper particles to facilitate pressure/heat bonding and create a conductive metallurgical bond. Cutting speed sensitive. Good for electronics. Used in thermoelectric applications. Good thermal fatigue behavior. Indalloy 281 Bi-Sn Solder Alloy Established history of use. It expands slightly during casting, so it shrinks or expands very little, unlike many other low-temperature alloys, which continue to change size for a few hours after solidification. 42 58 Bi58Pb42 124/126 Indalloy 67 Lead-Bismuth Pb Solder Alloy 42 58 In80Pb15Ag5 142/149149/154 Indalloy 2 In-Pb-Ag Pb Solder Alloy Non-In80. Gold compatible, minimal gold leaching. Resistant to thermal fatigue. Can be used in step welding. 15 5 80 Pb60In40 195/225 Pb not In40. Low Gold Leach. Good thermal fatigue properties. 60 40 PB70IN30 245/260 PB NO IN30 70 30 SN37.5PB37.5IN26 134/181 PB NO IN26 37.5 37.5 26 SN54PB26IN20 130/154 INDALY 532 ALOY ALOY PB IN20 54 20 PB81 PB81 PB81 EG202 LEGBEUNG LEGBEUNG LANGO5 LANGO4 20 EG202 LANGOBEUNG 20 PB81ING81ING 80 PB81 INGB81 INGB81 INGB81 INGB81 INGB81 IN20 PB81ING 0.50 PB81ING 0.50 PB81ING 80 PB81in. /280 260 260 260 232 Indalloy 150 Pb-In Solder Alloy Pb to In19. Low Gold Leach. Good thermal fatigue properties. 81 19 In52Sn48 118—yes In52. Suitable for cases where low temperature soldering is required. Can be used for glass sealing. Sharp melting point. Good wettability of glass, quartz and many ceramics. Good low temperature deformability, can accommodate different thermal expansion coefficients of composite materials. . It retains creep resistance well. It is not suitable for gold. 51.2 30.6 18.2 Sn77.2In20Ag2.8 175/187 Indalloy 227 Sn-In-Ag Solder Alloy - no mechanical properties similar to Sn63Pb37, Sn62Pb36Ag2 and Sn60Pb40, lead free replacement. Contains Sn-In eutectic phase with melting point at 118°C, avoid use above 100°C. 77.2 2.8 20 in74cd26 123 Indium CD Braze Yes 74 in61.7Bi30.8cd7.5 62 Indium CD Braze Yes 30.8 61.5 BI47.5PB25.6cd9.5in5 57/645 Inda Billoy 47.5 BI48pb25 .4SN12.8CD9.6IN4 61/65 INDALY 147 BISMUTH SOLDER ALLO 136. Expands slightly on cooling and shows a slight contraction a few hours later. It is used as a solder in low temperature physics. . It is used in low temperature physics as soldering. 13.3 26.7 50 10 Bi44.7Pb22.6In19.1Cd5.3Sn8.3 47 Cd,Pb yes Cerrolow 117. Used as a solder in low-temperature physics. LIPOWITZ 1. .4 1 4.5 13.1 ME IB50. 0Pb25.0Sn12.5Cd12.5 71 Pb,Cd yes Wood metal mainly used for foundries. 12.5 25 50 12.5 Bi50.0Pb31.2Sn18.8 97 Pb nonmetal from Newton 18.8 31.2 50 Bi50Pb28Sn22 109 Pb nonmetal from Rose. It was used to fasten cast iron railings and balusters into recesses in stone steps and bases. Does not shrink when cooled. 22 28 50 Cd95Ag5 338/393 Cd in KappTec Universal weld that joins all weldable metals except aluminium. High temperature and high strength welding. It is used in applications where alloys with a higher melting point than solder are required but do not require the cost and strength of silver solder alloys. 5 95 Cd82.5Zn17.5 265 Cd yes Medium temperature alloy offering strong, corrosion resistant bonds to most metals. Also for aluminum welding and die-casting of die-cast zinc alloys. It is used in low-temperature physics to connect electrical potential wires to metal samples, since this alloy does not become superconductive at liquid helium temperatures. 17.5 82.5 Cd70Zn30 265/300 Cd No Medium temperature alloy offering strong, corrosion resistant bonds to most metals. It is particularly well suited for aluminium-to-aluminium and aluminium-to-copper joints, with excellent corrosion resistance and superior strength in high-vibration and high-voltage electrical, lighting and electronic applications. 30 70 Cd60Zn40 265/316 Cd no Medium temperature alloy offering strong, corrosion resistant bonds to most metals. It is particularly well suited for aluminium-to-aluminium and aluminium-to-copper joints, with excellent corrosion resistance and superior strength in high-vibration and high-voltage electrical, lighting and electronic applications. 40 60 Cd78Zn17Ag5 249/316 Cd in KappTecZ High temperature, high strength solder that can be used on most metals but works very well on aluminium, copper and stainless steel. It has high vibration and stress tolerance and good elongation for use on dissimilar metals. Above its 600°F liquidus, this solder is extremely fluid and penetrating

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Weld the tightest connections. 5 17 78 Sn40Zn27Cd33 176/260 Cd on KappRad Specially developed for connecting and repairing aluminum and aluminum/copper radiators and heat exchangers. A lower melting point makes delicate repair work easier. 40 27 33 Zn90Cd10 265/399 Cd For welding aluminium. Good hydration. 90 10 Zn60Cd40 265/335 Cd For welding aluminium. Very good hydration. 60 40 Cd70Sn30 140/160 Cd not Cd70, no heat soldering. Generates copper low-temperature EMF connections, does not form parasitic thermocouples. It is used in low temperature physics. 29.56 70.44 Sn50Pb32Cd18 145 Cd,Pb Cd18 50 32 18 Sn40Pb42Cd18 145 Soft solder. www.cupalloys.co.uk (2009-01-20). Accessed on 06/07/2010. Cd, Pb Low melting point allows repair of tin and zinc objects, including cast toys. 40 42 18 Zn70Sn30 199/376 – no For welding aluminium. Excellent moisturizer. Good resistance 30 70 Zn60Sn40 199/341 – no For welding aluminium. Good hydration. 40 60 Zn95Sn5 382 – yes? For welding aluminum. Excellent moisturizer. 5 95 Sn90Au10 217 Indalloy 238 Sn-Au Braze – yes 90 10 Au80Sn20 280 – yes Au80. Good wetting, high strength, low creep, high corrosion resistance, high thermal conductivity, high surface tension, zero wetting angle. Suitable for step welding. The original alloy without flux, no flux required. It is used to attach metal chips and caps to semiconductor packages, such as Kovar caps for ceramic chip holders. Expansion coefficient that matches many common materials. Because the wetting angle is zero, pressure is required to form a void-free bond. Alloy of choice for joining gilded and gilded surfaces. Since soldering removes some of the gold from the surfaces and changes the composition to a non-eutectic state (a 1% increase in Au content can increase the melting point by 30°C), subsequent desoldering requires a higher temperature. Gold-Tin: The unique eutectic solder alloy forms a mixture of two intermetallic phases composed of brittle intermetallic compounds, AuSn and Au5Sn. Fragile. Good wetting is generally achieved by using nickel finishes with a layer of gold on both sides of the joint. Fully tested through military standard environmental conditions. Good long-term electrical performance, history of reliability. Low pressure steam suitable for vacuum work. It is generally used in applications that require a melting temperature greater than 150°C. Indalloy 182 tin-gold solder paste. Good ductility. Also classified as brazing. 20 80 Au98Si2 370/800 - Au98. A non-eutectic alloy used for bonding silicon dies (integrated circuits). Ultrasonic assistance is required to rub the surface of the chip so that a eutectic (3.1% Si) is achieved on reflow. 98 Si2 Au96.8Si3.2 370 363 Indalloy 184 Gold Solder Alloy - yes Au97. AuSi3.2 is a eutectic with a melting point of 363°C. Unlike AuSn, AuSi forms a meniscus at the edge of the chip because AuSi reacts with the surface of the chip. It forms a composite structure of submicron silicon wafers in a soft gold matrix. Slow and sustained crack propagation. 96.8 Si3.2 Au87.5Ge12.5 361 356 - yes Au88. It is used for fixing dies of some chips. High temperatures can be detrimental to chips and limit reworkability. 87.5 Ge12.5 Au82In18 451/485 - without Au82. High temperature, extremely hard, very stiff. 18 82 IndianIn100 157—Pure In99. It is used for fixing dies of some chips. Best for soldering gold, gold dissolves 17 times slower than tin based solders and up to 20% gold can be tolerated without significant embrittlement. Good behavior at cryogenic temperatures. Will wet many surfaces including quartz, glass and many ceramics. Under load, it deforms indefinitely. It does not become brittle even at low temperatures. Used as a solder in low-temperature physics, it bonds to aluminum. It can be used to weld thin metal or glass foils with an ultrasonic welder. 99.99 Notes on the above table The temperature ranges for solidus and liquidus (the soft state limits) are listed as solidus/liquidus. With Sn-Pb alloys, the tensile strength increases with increasing tin content. Indium-indium-tin alloys with high indium content have very low tensile strength. For soldering semiconductor materials, e.g. when joining silicon, germanium and gallium arsenide, it is important that the solder contains no impurities that could cause doping (semiconductor doping) in the wrong direction. For soldering n-type semiconductors, the solder can be doped with antimony; Indium can be added for soldering p-type semiconductors. Pure tin and pure gold can be used. Various fusible alloys can be used as solders with very low melting points; Examples are Fields metal, Lipowitz alloy, Woods metal and Roses metal. Properties The thermal conductivity of common solders varies between 32 and 94 W/(m·K) and the density between 9.25 and 15.00 g/cm3. Thermal properties of metals, conductivity, thermal expansion, specific heat Material Thermal conductivity [W/(m*K)] Melting point [°C] Sn-37Pb (eutectic) 50.9 183 Sn-2.8Ag-20.0In 53.5 175 – 186 Sn -2.5Ag-0.8Cu-0.5Sb 57.26 215 – 217 Pb-5Sn 63 310 Lead (Pb) 35.0 327.3 Tin (Sn) 73.0 231.9 Aluminum (Al) 240 660.1 Copper (Cu) 393 - 401 1083 FR-4 1.7 Solidification The solidification behavior depends on the alloy

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solder composition. Pure metals solidify at a well-defined temperature and form single-phase crystals. Eutectic alloys also solidify at a single temperature, with all components precipitating simultaneously in what is known as coupled growth. Upon cooling, non-eutectic compositions begin to precipitate the non-eutectic phase first; Dendrites if metal, large crystals if intermetallic. This mixture of solid particles in a molten eutectic is called the soft state. Even a relatively small proportion of solids in the liquid can drastically reduce its flowability. The overall solidification temperature is the solidus of the alloy, the temperature at which all components melt is the liquidus. The soft state is desirable where a certain degree of plasticity is beneficial to the joint making, to fill larger gaps or to clean the joint (e.g. when welding pipes). This can be disadvantageous when soldering electronic components by hand, as the connection can appear solid when it is not. Premature manipulation of the seal changes its internal structure and compromises the mechanical integrity. Functions of Alloying Elements Different elements play different roles in the solder alloy: Antimony is added to increase strength without affecting wettability. Prevents tin rot. Avoid zinc, cadmium, or electroplated metals as the resulting bond is brittle. Bismuth significantly lowers the melting point and improves wettability. In the presence of sufficient lead and tin, bismuth forms Sn16Pb32Bi52 crystals with a melting point as low as 95 °C, which diffuse along the grain boundaries and can lead to bond failure at relatively low temperatures. Therefore, a high performance part pre-tinned with a lead alloy may desolder under load when soldered with a solder containing bismuth. These seals are also prone to cracking. Alloys with more than 47% Bi expand on cooling, which can be used to compensate for thermal expansion misfit stresses. Slows the growth of Tin Whiskers. Relatively expensive, limited availability. Copper lowers the melting point, improves thermal fatigue resistance, and improves the wetting properties of molten solder. It also reduces the rate of dissolution of copper from the board and some of the conductors in liquid solder. It forms intermetallic compounds. It can promote the growth of tin whiskers. A supersaturated (about 1%) solution of copper in tin can be used to prevent the dissolution of the thin film metallization under the warp of bead grid array BGA chips, e.g. as Sn94Ag3Cu3.King-Ning-Tu Solder Joint Technology: Materials, Properties, and Reliability (Springer 2007) Nickel can be added to the solder alloy to form a supersaturated solution to prevent the dissolution of the thin film metallization under the bump. melting point and improves ductility. In the presence of lead, it forms a ternary compound that changes phase at 114 °C. Very high cost (several silvers), low availability. It rusts easily, causing problems in repairs and rework, especially where flux cannot be used to remove rust, for example. during fixation of the GaAs template. Indium alloys are used for cryogenic applications and for soldering gold because gold is much less soluble in indium than in tin. Indium can also weld many non-metals (e.g. glass, mica, alumina, magnesia, titania, zirconia, porcelain, brick, concrete and marble). Tends to diffuse in semiconductors and causes unwanted doping. At elevated temperatures it readily diffuses through metals. Low vapor pressure, suitable for use in vacuum systems. Forms brittle intermetallics with gold; Indium-rich solders on coarse gold are unreliable. Indium-based solders are susceptible to corrosion, especially in the presence of chloride ions. Lead is cheap and has suitable properties. Poorer wetting than tin. Toxic, will be eliminated. Slows the growth of tin whiskers, inhibits tin pests. Reduces the solubility of copper and other metals in tin. Silver offers mechanical strength but has poorer ductility than lead. In the absence of lead, it improves resistance to fatigue due to temperature changes. When using SnAg solders with HASL-SnPb sheathed conductors, the SnPb36Ag2 phase forms with a melting point of 179 °C, which migrates to the solder interface of the board, finally solidifies and detaches from the board. The addition of silver to tin significantly reduces the solubility of silver coatings in the tin phase. In the eutectic tin-silver alloy (3.5%Ag), it tends to form Ag3Sn platelets which, if formed near a point of high stress, can serve as sites of crack initiation; the silver content must be kept below 3% to prevent such problems. Tin is the usual main structural metal in the alloy. It has good resistance and wetting. Alone it is susceptible to rust, tin and tin whisker growth. Easily dissolves silver, gold and to a lesser extent, but still significantly, many other metals e.g. Copper; this is a particular problem with tin-rich alloys with higher melting points and reflux temperatures. Zinc lowers the melting point and is inexpensive. However, it is very susceptible to corrosion and oxidation in air, making zinc-containing alloys unsuitable for some purposes, for example wave soldering, and solder pastes that contain zinc have a shorter service life than those that do not contain zinc. In contact with copper, it can form brittle Cu-Zn intermetallic layers. It oxidizes easily, makes it difficult to wet and requires an appropriate flux. The germanium in tin-based lead-free solders affects the formation of oxides; under

160

Welding 0.002% increases the formation of oxides. The optimum concentration to suppress oxidation is 0.005%. Balver Zinn Desoxy RSNI Weld Impurities Impurities generally enter the weld metal by dissolving metals present in the assemblies being brazed. Dissolution of process equipment is not common as materials are generally chosen to be insoluble in the solder. Aluminum: Low solubility, causes slow soldering and a dull, grainy appearance due to oxide formation. The addition of antimony to solders forms Al-Sb intermetallic compounds which segregate into slag. Antimony: intentionally added, up to 0.3% improves wetting, larger amounts slowly worsen wetting Arsenic: forms fine intermetallic compounds with adverse effects on mechanical properties, causes drying of brass surfaces Cadmium: causes slow soldering, forms oxides and tarnishes Copper - most common impurity, forms acicular intermetallic compounds, causes slow welds, graining in alloys, reduced wetting Gold - dissolves easily, forms brittle intermetallic compounds, impurities above 0.5% slow down and reduce wetting. Lowers the melting point of tin-based solders. Alloys with high tin content can hold more gold without becoming brittle. Iron: forms intermetallic compounds, causes granulation, but dissolution rate is very slow; easily dissolves in lead-tin above 1000°F. Nickel: causes sand, very low solubility in Sn-Pb Phosphorus: forms tin and lead phosphides, causes sand and desiccation, present in electroless nickel plating Silver: often added intentionally, forms intermetallic compounds in large quantities, which form sand and tar grains on the surface surface cause weld surface Sulfur – forms lead and tin sulphides, causes rewetting Zinc – forms excessive slag when molten, oxidizes quickly at surface in solidified compounds; Zinc oxide is insoluble in fluxes, which affects repairability; When soldering brass, barrier layers of copper and nickel may be required to prevent nickel migration to the surface. B. a ductile solid solution matrix, but can also form the matrix itself with metallic inclusions or form crystalline matter with various intermetallics. Intermetallics are generally hard and brittle. Finely divided intermetallics in a ductile matrix produce a hard alloy, while the coarse structure produces a softer alloy. As a rule, various intermetallic compounds are formed between the metal and the weld seam as the proportion of metal increases; B. form a Cu-Cu3Sn-Cu6Sn5-Sn structure. Layers of intermetallic compounds can form between the weld and the welded material. These layers can cause weakening and brittleness in mechanical reliability, increased electrical resistance or electromigration and cavitation. The gold-tin intermetallic layer is responsible for the poor mechanical reliability of soldered gold plated surfaces where the gold plating has not completely dissolved into the solder. Gold and palladium dissolve easily in solder. Copper and nickel tend to form intermetallic layers during normal profile welding. Indium also forms intermetallics. Indium-gold intermetallics are brittle and occupy about 4 times the volume of the original gold. Bond wires are particularly vulnerable to indium attack. This intermetallic growth, along with thermal cycling, can lead to bond wire failure. The cable results in brittle gold and indium connections and an unreliable condition that leads to breakage of the cable connection. Nickel-plated and gold-plated copper is commonly used. The thin layer of gold promotes the good weldability of the nickel, as it protects the nickel from oxidation; The layer must be thin enough to dissolve quickly and completely to expose the bare nickel to the solder. Tin-lead solder layers on copper conductors can form tin-copper intermetallics; then the solder alloy is locally tin-free and forms a lead-rich layer. Sn-Cu intermetallic compounds may be subject to oxidation, resulting in poor weldability. Two processes are involved in the formation of a solder joint: the interaction between the substrate and the molten solder and the solid-state growth of intermetallic compounds. The base metal dissolves in the molten solder in an amount dependent on its solubility in the solder. The active component in the solder reacts with the base metal at a rate that depends on the solubility of the active components in the base metal. Solid state reactions are more complex: the formation of intermetallic compounds can be prevented by changing the composition of the base metal or solder alloy, or by using an appropriate barrier layer to prevent the diffusion of metals. EstañoPlomoIndioCobre Cu4Sn, Cu6Sn5, Cu3Sn, Cu3Sn8 Cu3In, Cu9In4Nickel Ni3Sn, Ni3Sn2, Ni3Sn4 NiSn3 Ni3In, NiIn Ni2In3, Ni3In7Iron FeSn, FeSn2Indium In3Sn, InSn4 In3Pb – Antimony SbSn Bismuth BiPb3Silver Ag6Sn, Ag3Sn Ag3In, AgIn2GoldAu5Sn, AuSn AuSn2, AuSn4 Au2Pb, AuPb2 AuIn , AuIn2Palladium Pd3Sn, Pd2Sn, Pd3Sn2 , PdSn, PdSn2, PdSn4 Pd3In, Pd2In, PdIn Pd2In3Platinum Pt3Sn, Pt2Sn,

161

Solder PtSn, Pt2Sn3, PtSn2, PtSn4 Pt3Pb, PtPb PtPb4 Pt2In3, PtIn2, Pt3In7 Cu6Sn5: common at the solder-copper interface, preferably formed with excess tin; in the presence of nickel (Cu,Ni)6Sn5 the compound Cu3Sn can be formed – often at the solder-copper interface, preferentially formed when excess copper is present, more thermally stable than Cu6Sn5, often present in high temperature soldering Ni3Sn4 – often at the solder -Nickel interface FeSn2- very slow formation Ag3Sn- forms at higher concentrations of silver (more than 3%) in tin platelets that can serve as crack initiation sites. AuSn4– β-phase– brittle, formed with excess tin. Impairment of the properties of tin-based solders for gold-plated layers. AuIn2 - forms at the interface between gold and indium-lead solder, acts as a barrier to further dissolution of gold Glass Solder Glass solders are used to join glass to other glasses, ceramics, metals, semiconductors, mica and other materials in a process called frit binding. The glass solder must flow and wet the soldered surfaces well below the temperature at which deformation or degradation of any of the bonded materials or nearby structures (e.g., plating layers on chips or ceramic substrates) will occur. The usual flow and wetting temperature is between 450 and 550°C. Two types of glass solder are used: glass solder and devitrification. Glassy solders retain their amorphous structure when remelted, can be reworked again and again and are relatively transparent. Devitrification solders partially crystallize during solidification and form a glass ceramic, a composite of glass and crystalline phases. Devitrification welds tend to create a stronger mechanical bond, but are more temperature sensitive and the seal is more likely to leak; Because of their polycrystalline structure, they tend to be translucent or opaque. Devitrification solders are often "thermoset" since their melting temperature becomes significantly higher after recrystallization; This allows the parts to be welded together at a lower temperature than the subsequent drying, without later remelting the joint. Devitrification solders usually contain up to 25% zinc oxide. In the manufacture of cathode ray tubes, devitrifying solders based on PbO-B2O3-ZnO are used. Very low melting glasses, liquid at 200-400°C, were developed for electronic sealing applications. They can consist of binary or ternary mixtures of thallium, arsenic and sulfur. Zinc silicoborate glasses can also be used to passivate electronic components; their coefficient of thermal expansion must correspond to that of silicon (or other semiconductors used) and they must not contain any alkali metals, as these would migrate into the semiconductor and lead to failure. The bond between the glass or ceramic and the glass solder may be a covalent-covalent bond or, more commonly, a van der Waals-Force van der Waals bond. The seal can be hermetic; Glass welding is often used in vacuum technology. Glass solders can also be used as sealants; A layer of vitreous enamel over iron reduced its hydrogen permeability tenfold. Glass solders are commonly used for glass-to-metal seals and glass-ceramic-to-metal seals. Glass solders are available as powder frits with a grain size of less than 60 microns. They can be mixed with water or alcohol to form an easy-to-apply paste, or with dissolved nitrocellulose or other suitable binder to adhere to surfaces until melted. Any binder must be fired before proceeding with melting, which requires a careful ceramic firing regime. Welding glass can also be applied in the molten state in the area of the subsequent joint during the manufacture of the component. Due to their low viscosity in the molten state, lead glasses with a high content of lead (II) oxide PbO (typically 70-85%) are often used. The most common compositions are based on lead borates (lead borate glass or borosilicate glass). A small amount of zinc oxide or aluminum oxide may be added to increase chemical stability. Phosphate glasses can also be used. Zinc oxide, bismuth trioxide and cupric oxide can be added to influence thermal expansion; unlike alkali oxides, they lower the softening point without increasing thermal expansion. Glass solders are widely used in electronic packaging. The CERDIP package is an example. Solder glass outgassing during encapsulation was one of the causes of the high failure rates of early CERDIP integrated circuits. Removal of glass-bonded ceramic coatings, for example to reach the chip for failure analysis or reverse engineering, is best done by shear (physical); if it's too risky, the deck will be polished. Because seals can be made at a much lower temperature than when joining pieces of glass directly and without the use of a flame (using a temperature-controlled oven or kiln), glass solders are useful. B. in applications such as subminiature vacuum tubes or for connecting mica windows to vacuum tubes and instruments (e.g. Geiger tube). The coefficient of thermal expansion must match the materials to be joined and is usually chosen from the coefficients of expansion of the materials. In the case where compromises must be made, it is more desirable to subject the connection to compressive stress than to tensile stress. The expansion game is not

162

welding

163

critical in applications where thin layers are used in small areas, e.g. B. in the case of burn-through paints, or where the connection is exposed to permanent compression (e.g. by an outer steel jacket) in order to compensate for thermally introduced tensile stresses. Glass solder can be used as an intermediate layer when joining materials (glass, ceramics) with significantly different thermal expansion coefficients; such materials cannot be joined directly by diffusion bonding. Vacuum glazing windows consist of glass panes welded together. A glass solder is used, for example, to join parts of cathode ray tubes and plasma screens. Recent compositions have reduced the service temperature from 450 to 390°C by reducing the lead(II) oxide content by 70%, increasing the zinc oxide content, adding titanium dioxide and bismuth(III) oxide and some other components. The high thermal expansion of this glass can be reduced by a suitable ceramic filler (material). Lead-free solder lenses with a soldering temperature of 450°C have also been developed. Low melting temperature phosphate glasses have been developed. One such composition is phosphorus pentoxide, lead(II) oxide and zinc oxide, with the addition of lithium and some other oxides. Conductive glass solders can also be made. Preform A preform is a ready-made weld shape specifically designed for the application in which it is to be used. Welding Preforms Many methods are used to make the solder preforms, with stamping being the most common. The solder preform may contain solder flux required for the soldering process. It can be internal flux within the solder preform or external where the solder preform is coated. References Bibliography Sanka Ganesan, Michael Pecht (2006). Lead-free electronics. wiley. International Standard Book Number ISBN0-471-78617-9. External links Table of physical properties of solder Lead-free solder alloys Common solder alloys and their melting ranges Phase diagrams of different types of solder alloys Phase diagrams for lead-free solders Lead Lead

Ductility In materials science, ductility is the ability of a solid material to deform under tension; This is usually characterized by the material's ability to stretch into a thread. Formability, a related property, is the ability of a material to deform under compressive stress; this is usually characterized by the material's ability to be formed into a thin sheet by hammering or rolling. Both mechanical properties are aspects of plasticity, the extent to which a solid material can be plastically deformed without breaking. In addition, these material properties are dependent on temperature and pressure (studied by Percy Williams Bridgman as part of his Nobel Prize-winning work on high pressures). Ductility and formability are not always equally extended; For example, while gold is ductile and malleable, lead is only malleable.[1] The word ductility is sometimes used to encompass both types of plasticity.[2]

Tensile test of an AlMgSi alloy. Goblet and cone shaped local crush and fracture surfaces are typical of ductile metals.

ductility

164

This tensile test of a ductile iron shows poor ductility.

Materials Science Ductility is particularly important in metallurgy because materials that crack or fracture under stress cannot be manipulated by metal forming processes such as hammering, rolling, and drawing. Malleable materials can be formed by stamping or pressing, while fragile metals and plastics must be formed. High levels of ductility occur because of metallic bonds, which are predominantly found in metals and lead to the general perception that metals are generally ductile. In metallic bonds, the valence shell electrons are delocalized and shared by many atoms. Delocalized electrons allow metal atoms to slide past one another without being subjected to the strong repulsive forces that would cause other materials to be pulled apart. Ductility can be quantified by breaking stress

Gilding is possible due to the malleability of gold.

, that is the technical load to which a sample is exposed.

Fractures during a uniaxial tensile test. Another frequently used measure is the reduction of the fracture surface.

.[3]

The ductility of steel varies depending on the alloy components. Increasing carbon levels reduce ductility. Many plastics and amorphous solids like Play-Doh are also malleable. The most ductile metal is platinum and the most malleable metal is gold [4][5]

ductility

165

Ductile-brittle transition temperature The ductile-brittle transition temperature (DBTT), zero ductility temperature (NDT) or zero ductility transition temperature of a metal represents the point at which the fracture energy falls below a specified point (for steels typically 40 J[ 6 ] for a standard Charpy impact test). The DBTT is important because once the material cools below the DBTT, it has a much greater tendency to fracture on impact than it does to bend or warp. For example, Zamak 3 shows good ductility at room temperature, but cracks when loaded at sub-zero temperatures. DBTT is a very important consideration in material selection when the material in question will be subjected to mechanical stress. A similar phenomenon, the glass transition temperature, occurs in glasses and polymers, although the mechanism is different in these amorphous materials.

Schematic appearance of metallic rods after the tensile test. (a) brittle fracture (b) ductile fracture (c) fully ductile fracture

With some materials this transition is more pronounced than with others. For example, the transition is generally more pronounced in body-centered cubic (BCC) lattice materials than in those with a face-centered cubic (FCC) lattice. DBTT can also be affected by external factors such as neutron radiation, leading to an increase in internal lattice defects and a corresponding decrease in ductility and an increase in DBTT. The most accurate method of measuring the BDT or DBT temperature of a material is the fracture test. Typically, the four-point bend test is performed over a range of temperatures on pre-cracked bars of polished material. In experiments performed at higher temperatures, the displacement activity increases. Above a certain temperature, the dislocations protect the crack tip so strongly that the applied strain rate is not sufficient for the stress intensity at the crack tip to reach the critical fracture value (KiC). The temperature at which this occurs is the ductile-brittle transition temperature. If the tests are run at a higher strain rate, more dislocation protection is required to avoid brittle fracture and the transition temperature is increased.

References [1] . [2] Includes definitions from the American Heritage Dictionary of the English Language, Collins English Dictionary: Complete and Unabridged, American Heritage Science Dictionary, and WordNet [3] G. Dieter, Mechanical Metallurgy, McGraw-Hill, 1986, ISBN 978-0- 07-016893-0 [4] Manual of Materials, Mc Graw-Hill Manuals, by John Vaccaro, Fifteenth Edition, 2002 [5] CRC Encyclopedia of Materials, Parts and Finishes, Second Edition, 2002, M. Schwartz [6] John , Vernon. Introduction to Technical Materials, 3rd Ed.(?) New York: Industrial Press, 1992. ISBN 0-8311-3043-1.

External Links • Definition of ductility on Engineersedge.com (http://www.engineersedge.com/material_science/ductility.htm) • DoITPoMS teaching and learning package: “The Ductile-Fragile Transition” (http://www.doitpoms . ac.uk/tlplib/ductile-brittle-transition/index.php)

Gold

166

Goldgold Au 79

Platinum ← Gold → MercuryAg ↑

Au ↓ Rg Gold on the Periodic Table Yellow metallic appearance

General Properties Name, Symbol, Number

Gold, Au, 79

pronunciation

/ˈɡoʊld/

item category

transition metal

group, period, block

11, 6, gest

standard atomic weight

196.966569(4)

Gold

167 Electronic configuration

[Vehicle] 4f14 5d10 6s1 2, 8, 18, 32, 18, 1

story name

aurum in Latin, meaning brightness of dawn

discovery

Middle East (before 6000 BC) Physical Properties

Phase

fest

Density (near room temperature)

19,30 g·cm−3

Density of the liquid in m.p.

17,31 g·cm−3

fusion point

1337,33 K, 1064,18 °C, 1947,52 °F

boiling point

3129K, 2856°C, 5173°F

heat of fusion

12.55 kJ·mol-1

heat of vaporization

324 kJ·mol-1

molar heat capacity

25.418 J mol-1 K-1 vapor pressure

P (Pa)

100

1 k

10 thousand 100 thousand

in T (K) 1646 1814 2021 2281 2620 3078 Atomic Properties Oxidation States

5, 4, 3, 2, 1, -1, -2 (amphoteres Oxid)

electronegativity

2.54 (Pauling Scale)

ionization energies

1st: 890.1 kJ mol-1 2nd: 1980 kJ mol-1

Atomic func

144 hours

covalent ray

136±18:00

Radio Van der Waals

166h Miscellaneous

Gold

168 crystal structure

face-centered cubic lattice

magnetic request

diamagnetic

Electrical resistance

(20°C) 22,14 nΩ·m

thermal conductivity

318W·m−1·K−1

thermal expansion

(25 °C) 14,2 µm·m−1·K−1

[1]

Speed of sound (thin bar) (r.t.) 2030m s−1 Tensile strength

120 MPa

modulus of elasticity

79 GPa

Schneidmodul

27 GPa

Volumenmodul

180 [citation needed] GPa

poison ratio

0,44

Mohs hardness

2.5

Dureza Vickers

216 MPa

Brinell hardness

25 HP = ?? MPa

CAS registration number

7440-57-5 Stabilste Isotope

Main article: Isotopes of isogold

THE

half-life

195

sin

186,10 Euro

0,227

195

196

sin

6,183 diam

1.506

196

b−

0,686

196

same same same

Au 100%

197

DM OF (MeV)

Pt Pt Pt

197

Au is stable with 118 neutrons

198

sin

2.69517 dia

b−

1.372

198

199

sin

3,169 diam

b−

0,453

199

same same same

Hg Hg

Gold is a chemical element with the symbol Au and atomic number 79. It is a dense, soft, malleable, and ductile metal with a pale yellow color and an attractive luster that remains unstained in air or water. Chemically, gold is a transition metal and a Group 11 element. It is one of the least reactive chemical elements and is solid under standard conditions. Thus, the metal is normally found in free (native) elemental form as nuggets or grains in rocks, in veins, and in alluvial deposits. Less commonly, it is found in minerals such as gold compounds, usually with tellurium. Gold also dissolves in alkaline cyanide solutions used in mining. It dissolves in mercury and forms amalgam alloys; It is insoluble in nitric acid, which dissolves silver and base metals, a property long used to confirm the presence of gold in objects, giving rise to the term acid test.

Gold

169 Long before recorded history began, this metal was a valuable and coveted precious metal for coins, jewelry, and other handicrafts. Gold standards were sometimes monetary policy, but were largely supplanted by fiat money beginning in the 1930s. The last gold certificates and gold coins were issued in the United States in 1932. In Europe most countries gave up the gold standard after World War I in 1914 and with huge war debts I did not return to gold as currency. Exchange. According to GFMS in 2012, a total of 174,100 tons of gold have been mined in human history.[2] This is equivalent to about 5.6 billion troy ounces, or about 9,261 m3 by volume, or a 21.0 m cube. World consumption of newly produced gold is about 50% in jewellery, 40% in investments and 10% in industry. [] In addition to its broad monetary and symbolic functions, gold has many practical uses in dentistry, electronics, and other fields. Its high malleability, ductility, resistance to corrosion and most other chemical reactions, and electrical conductivity have led to many uses including electrical wiring, the manufacture of colored glass, and gold leaf. Most of the Earth's gold is in its core, and the metal's high density causes it to sink there in the planet's youth. It is believed that virtually all gold discovered was later deposited by meteorites containing the element,[3][4][5][6][7] and the cratering asteroid Vredefort has been implicated in the formation of newer gold . Great. Land mine region, Witwatersrand Basin.[8][9][10][11]

Etymology "Gold" is related to similar words in many Germanic languages and derives from Proto-Germanic *gulþą from Proto-Germanic *gʰel- ("yellow/green").[12][13] The symbol Au derives from Latin: aurum, which according to some sources means "bright dawn",[14] from Sabine ausum "bright dawn"[15], although according to the definitions of the Latin dictionaries, the meaning of the word aurum is extended only to the same as the current reference to metal.[16] The disagreement between the definitions is possibly due to the accumulation of evidence from archeology for the metal's original age in civilization; in relation to the "dawn of civilization"[17] and in this sense has become the accepted modern meaning, detached from the original etymological Latin.[18]

Properties Gold is the most malleable of all metals; A single gram can hit a 1 square foot leaf or an ounce to 300 square feet. Gold leaf can be beaten thin enough to become transparent. Transmitted light appears blue-green because gold strongly reflects yellow and red.[19] These semi-transparent films are also highly reflective of infrared light, making them useful as infrared (radiant heat) shields in heat-resistant suit visors and space suit sun visors.[20] Gold easily forms alloys with many other metals. These alloys can be made to modify hardness and other metallurgical properties, control the melting point, or create exotic colors.[] Gold is a good conductor of heat and electricity, and highly reflective of infrared radiation. Chemically unaffected by air, moisture and most corrosive reagents, it is excellent for use on coins and jewelry, and as a protective coating on other more reactive metals. However, it is not chemically inert. Gold is almost insoluble but can be dissolved in aqua regia. Common oxidation states of gold are +1 (gold(I) or gold compounds) and +3 (gold(III) or gold compounds). Gold ions in solution are easily reduced and precipitated as a metal by adding any other metal as a reducing agent. The added metal oxidizes and dissolves, allowing the gold to come out of solution and be recovered as a solid precipitate. In addition, gold is very dense, one cubic meter weighs 19,300 kg. For comparison: the density of lead is 11,340 kg/m3 and that of the densest element osmium is 22,610 kg/m3.

Gold

170

Color While most other pure metals are gray or silvery white, gold is yellow. This color is determined by the density of weakly bound (valence) electrons; these electrons oscillate as a collective "plasma" medium, described in terms of a quasiparticle called a plasmon. The frequency of these oscillations is in the ultraviolet for most metals, but falls into the visible for gold due to subtle relativistic effects affecting the orbitals around gold atoms. Similar effects give metallic cesium a golden hue. Gold alloys in common colors such as rose gold can be made by adding varying amounts of copper and silver as indicated in the triangle diagram to the left. Various colors of Ag-Au-Cu alloys. Alloys containing palladium or nickel are also important for commercial jewelry as they produce white gold alloys. Less commonly, the addition of manganese, aluminum, iron, indium, and other elements can produce more unusual gold colors for many applications.[]

Isotopes Gold has only one stable isotope, 197Au, which is also its only natural isotope. 36 radioisotopes with atomic masses from 169 to 205 were synthesized. The most stable of these is 195Au with a half-life of 186.1 days. The least stable is 171Au, which decays by proton emission with a half-life of 30 µs. Most gold radioisotopes with atomic masses less than 197 decay by a combination of proton emission, α-decay, and β+-decay. Exceptions are 195Au, which decays by electron capture, and 196Au, which decays more frequently by electron capture (93%) and has a shorter β-decay pathway (7%).[23] All radioisotopes of gold with atomic masses greater than 197 decay by β-decay. 188Au has no isomers. The most stable gold isomer is 198m2Au with a half-life of 2.27 days. The least stable isomer of gold is 177 m2Au with a half-life of only 7 ns. 184 m1Au has three decay pathways: β+ decay, isomeric transition, and alpha decay. No other isomer or isotope of gold has three decay pathways.[ ]

Applications Currency Exchange Gold is widely used around the world as a vehicle for currency exchange, either through the issuance and recognition of gold coins or other amounts of pure metal, or through paper instruments that can be converted to gold through the adoption of gold standards. The total value of coins issued in cash is converted into shown in a depot of gold reserves. The first Greek gold coins were minted around 700 BC. minted in Lydia. c.[24] Talented gold coin used in periods of Greek history before and during Homer's lifetime. Gold is commonly converted into bullion for use in currency exchange. it weighed between 8.42 and 8.75 grams.[25] Based on an earlier preference for the use of silver, European economies reintroduced gold coins in the 13th and 14th centuries.[]

Gold

171 However, production has not grown relative to the global economy. Today, gold mine production is declining.[26] With the rapid growth of economies in the 20th century and the rise of currencies, the world's gold reserves and trading market have become a small fraction of all markets, and fixed exchange rates of currencies for gold are no longer maintained. At the start of World War I, the warring nations switched to a fractional gold standard and inflated their currencies to fund the war effort. After World War II, gold was replaced by a convertible currency system based on the Bretton Woods system. Gold standards and the direct convertibility of currencies into gold have been abandoned by world governments and replaced with fiat currencies. Switzerland was the last country to peg its currency to gold; until Switzerland joined the International Monetary Fund in 1999, it secured 40% of its value.[27] The gold content of alloys is measured in carats (k). Pure gold is referred to as 24k. English gold coins intended to be circulated from 1526 to 1930 were typically a 22 karat standard alloy called crown gold [28] because of their hardness (US gold coins circulated after 1837 contained slightly less). 0.900 fine gold or 21.6 kt) [29] Although the prices of some platinum group metals can be much higher, gold has long been considered the most desirable of the precious metals and its value has been used as a benchmark for many coins. Gold has been used as a symbol of purity, value, royalty, and especially papers that combine these qualities. Gold as a sign of wealth and prestige was ridiculed by Thomas More in his treatise Utopia. Gold is so plentiful on this imaginary island that it is used to make slave chains, dishes and toilet seats. When ambassadors from other lands arrive, clad in ostentatious jewels and golden insignia, the utopians regard them as lowly servants and pay homage to the humblest of their group.

Investment Many gold owners store it in the form of gold or bullion as a hedge against inflation or other economic disruptions. However, economist Martin Feldstein does not believe that gold serves as a hedge against inflation or currency depreciation.[30] The ISO 4217 gold coin code is XAU. Modern gold coins for investment or collector purposes do not require good mechanical wear properties; are gold prices (US$ per troy ounce), in nominal US$ and inflation-adjusted US$. typically 24k fine gold, although the American Gold Eagle and British Gold Sovereign continue to be minted in 22k metal in the historical tradition and the South African Krugerrand, first cast in 1967, is also 22k. The Canada Maple Leaf Special Edition gold coin contains the purest gold of any gold coin at 99.999% or 0.99999, while the popular Canadian Maple Leaf gold coin is 99.99% pure. Several other 99.99% pure gold coins are available. In 2006, the United States Mint began producing American Buffalo gold coins that are 99.99% pure. Australian gold kangaroos were first minted as an Australian gold nugget in 1986, but changed the reverse design in 1989. Other modern coins include the Vienna Philharmonic gold coin of Austria and the Chinese gold panda.

Gold

172

Jewelry Because of the softness of pure gold (24k), for use in jewelry it is often alloyed with base metals, altering its hardness and ductility, melting point, color, and other properties. Lower karat alloys, typically 22k, 18k, 14k or 10k, contain higher percentages of copper or other base metal or silver or palladium in the alloy. Copper is the most commonly used base metal and produces a redder color.[32] 18k gold with 25% copper is found in antique and Russian jewelry and has a distinctive, though not dominant, copper cast moche gold collar depicting cat heads. making rose gold. The 14k gold and copper alloy is almost identical to the Museo Larco collection. Lima-Peru in color for certain bronze alloys, both of which can be used to make police and other insignia. Blue gold can be made by gluing iron, and purple gold can be made by gluing aluminum, although this is rarely done except for specialty jewelry. Blue gold is more fragile and therefore more difficult to process in jewelry.[32] Alloying 14 and 18 karat gold with silver alone appears greenish yellow in color and is referred to as green gold. White gold alloys can be made with palladium or nickel. 18k white gold with 17.3% nickel, 5.5% zinc and 2.2% copper has a silvery appearance. However, nickel is toxic and its release from nickel white gold is controlled by European legislation.[32] Alternative white gold alloys based on palladium, silver, and other white metals are available,[32] but palladium alloys are more expensive than nickel alloys. High quality white gold alloys are significantly more resistant to corrosion than pure silver or sterling silver. The Japanese craft of Mokume-gane uses color contrasts between colored gold alloys that are rolled to create decorative wood grain effects.

Medicine Conceived as perhaps the oldest drug administered (apparently according to a source of shamanic practitioners)[33] and known to Dioscurides,[34][35] however the apparent paradoxes of the substance's actual toxicology suggest the possibility of what serious gaps in the understanding of the effect in physiology.[36] In the Middle Ages, gold was often considered to be good for health, in the belief that something so rare and beautiful could only be healthy. Even some modern esotericists and forms of alternative medicine attribute healing powers to metallic gold.[37] Some gold salts have anti-inflammatory properties and are used as medicines to treat arthritis and related conditions. Gold-based injections have been studied as a means of reducing pain and inflammation in rheumatoid arthritis and tuberculosis. [] However, only gold salts and radioisotopes have any pharmacological value, since as elemental (metallic) gold it is inert to all chemicals it contains. encounters in the body. Gold alloys are used in restorative dentistry, particularly in tooth restorations such as permanent crowns and bridges. The easy malleability of gold alloys facilitates the creation of a superior mating surface of molars with other teeth and generally produces more satisfactory results than those obtained by fabricating porcelain crowns. The use of gold crowns on more prominent teeth, such as B. incisors, is preferred in some cultures and not recommended in others. Colloidal gold preparations (suspensions of gold nanoparticles) in water are dark red in color and can be prepared by reduction of gold chloride with citrate or ascorbate ions with strictly controlled particle sizes down to tens of nanometers. Colloidal gold is used in research applications in medicine, biology and materials science. The immunogold labeling technique utilizes the ability of gold particles to adsorb protein molecules onto their surfaces. Colloidal gold particles coated with specific antibodies can be used as probes to detect the presence and location of antigens on cell surfaces.[38] In electron microscopic ultrathin tissue sections, immunogold markers appear as extremely dense round dots at the antigen position.[39]

Gold

173 Gold or alloys of gold and palladium are applied as a conductive coating to biological specimens and other nonconductive materials such as plastics and glass for viewing under a scanning electron microscope. The coating, normally applied by argon plasma spray, plays a triple role in this application. Gold's very high electrical conductivity directs electrical charge back into the earth, and its very high density provides stopping power to the electrons in the electron beam and helps limit the depth of the electron beam in the earth. This improves the definition of the position and topography of the sample surface and increases the spatial resolution of the image. Gold also generates a large number of secondary electrons when irradiated with an electron beam, and these low-energy electrons are the most commonly used signal source in the scanning electron microscope.[40] The isotope gold-198 (half-life 2.7 days) is used in nuclear medicine, some cancer treatments, and to treat other diseases.[41][42]

Food and Beverage • Gold can be used in food and has the E number 175.[] • Gold bread, flakes or powder is used as a decorative ingredient in some deli products, particularly candies and beverages.[43] The gold flake was used by the nobility of medieval Europe to decorate food and drink in the form of leaves, flakes or powder, either to demonstrate the richness of the Host or in the belief that something so precious and rare should be beneficial to health . . • Danziger Goldwasser (German: Goldwasser von Danzig) or Goldwasser (English: Goldwater) is a traditional German herbal liqueur[44] made in present-day Danzig, Poland, and Schwabach, Germany, containing flakes of gold leaf. There are also some expensive cocktails (around $1,000) that contain gold leaf flakes.[45] However, because metallic gold is inert to all body chemistry, it is tasteless, non-nutrient, and non-disruptive to the body.[46]

Industry • Gold solder is used to join gold jewelry components by soldering or high temperature soldering. If the work is to be of distinctive quality, the gold solder must match the karat weight of the work, and alloy formulas are made in most industry standard karat weights to match the color of the gold, yellow and white. Gold soldering is usually done in at least three melting point ranges labeled as light, medium and hard. By using high melting point braze, followed by progressively lower melting point solder, goldsmiths can assemble complex items with multiple separate solder joints.

The 220 kg gold bar on display at Jinguashi Gold Museum, Taiwan, ROC.

• Gold can be processed into thread and used for embroidery. • Gold produces a rich, deep red color when used as a colorant in cranberry jar. • In photography, gold toners are used to change the color of black and white prints to brown or blue tones or to increase their stability with silver bromide. Gold toners are used in sepia tone prints and produce red tones. Kodak has published formulas for several types of gold toner that use gold as the chloride.[47] • Gold is a good reflector of electromagnetic radiation such as visible and infrared light and radio waves. It serves the

Gold

174 Protective coatings on many artificial satellites, on infrared shields on astronauts' thermal suits and helmets, and on electronic warfare aircraft such as the EA-6B Prowler. • Gold is used as a reflective layer on some high-end CDs. • Cars can use gold as thermal protection. McLaren uses gold leaf in the engine compartment of its F1 model.[48] • Gold can be so thin that it appears transparent. It is used in some aircraft cabin windows for de-icing or anti-icing by passing electricity through it. The heat generated by the resistance of the gold is sufficient to prevent ice formation.[]

Electronics The concentration of free electrons in metallic gold is 5.90×1022 cm−3. Gold is a very conductive conductor of electricity and has been used for electrical wiring in some high energy applications (only silver and copper are more conductive by mass, but gold has the benefit of corrosion resistance). For example, electrical gold wires were used during some of the Manhattan Project's atomic experiments, but large, high-current silver wires were used in the project's Calutron isotope separation magnets.

The largest gold bar in the world has a mass of 250 kg. Toi Museum, Japan.

Although gold is attacked by free chlorine, its good conductivity and general resistance to oxidation and corrosion in other environments (including resistance to non-chlorinated acids) led to its widespread industrial use in the electronics age as a thin layer covering electrical connectors, thus ensuring a good connection. For example, gold is used in the connectors of more expensive electronic cables such as audio, video, and USB cables. The advantage of using a 5mm diameter gold nugget over other connecting metals such as tin in these applications (below) can be expanded upon by discussion; Often criticized by audiovisual experts for hammering away unnecessary gold leaf for most consumers, gold plated connectors are simply seen as a marketing ploy. However, 0.5 square meters. Toi Museum, Japan. The use of gold in other applications in electronic sliding contacts in highly humid or corrosive atmospheres and in the use of contacts with very high failure costs (certain computers, communications equipment, spacecraft, jet aircraft engines) remains very common[ 49] in addition to sliding electrical contacts, gold is also used in electrical contacts because of its corrosion resistance, electrical conductivity, ductility, and lack of toxicity.[50] Switching contacts are generally subject to higher corrosion stress than sliding contacts. Thin gold wires are used to connect semiconductor devices to their packages through a process known as wire bonding.

Commercial Chemistry Gold is attacked and dissolved in alkaline solutions of potassium or sodium cyanide to form saline gold cyanide, a technique that has been used to extract metallic gold from ores in the cyanide process. Gold cyanide is the electrolyte used in commercial gold plating on base metals and electroforming. Gold chloride (chloroauric acid) solutions are used to produce colloidal gold by reduction with citrate or ascorbate ions. Gold chloride and gold oxide are used to produce red or red glass containing uniformly sized spherical gold nanoparticles like colloidal gold suspensions.[51]

Gold

175

Cultural history Gold artefacts found in the Nahal Kana cave cemetery from the 1980s indicate their belonging to the Chalcolithic and are considered to be the oldest finds from the Levant (Gopher et al. 1990).[] Artefacts also occur. Balkans. from the fourth millennium BC. B.C. as found in the Varna necropolis near Lake Varna in Bulgaria and considered by one source (La Niece 2009) to be the oldest "well dated" find of gold artefacts. [] Gold artefacts, such as the Gold Hats and the Nebra Disc, began to appear in Central Europe from the 2nd millennium BC. C. Bronze Age.

The Papyrus Map of Turin

Egyptian hieroglyphs from 2600 BC describe gold that King Tushratta of Mitanni claimed there was "more than dirt" in Egypt.[52] Egypt and especially Nubia had the resources to make them major gold producing areas for much of history. The oldest known map is known as the Turin Papyrus Map and shows the plan of a gold mine in Nubia along with notes on the local geology. Primitive working methods are described by Strabo and Diodorus Siculus and involve the setting of fires. Large mines also existed beyond the Red Sea in present-day Saudi Arabia. The legend of the Golden Fleece may refer to the ancient use of wool to capture gold dust from alluvial deposits. Gold is mentioned frequently in the Old Testament beginning with Genesis 2:11 (in Havilah), the story of the golden calf and many parts of the temple including the menorah and the golden altar. In the New Testament it is included in the gifts of the wise men in the first chapters of Matthew. The book of Revelation 21:21 describes the city of New Jerusalem as having streets "of pure gold shining like crystal." Gold mining in the south-east corner of the Black Sea is said to date back to the time of Midas, and this gold was important in the establishment of what is believed to be the world's oldest coinage in Lydia around 610 BC. From the sixth or fifth century B.C. C., Chu (state) introduced the ying yuan, a type of square gold coin.

Grab mask of the Tutanchamun

In Roman metallurgy, the introduction of hydraulic mining methods, particularly in Hispania from 25 B.C. BC, new methods of large-scale gold mining were developed. and in Dacia from AD 106. Jason returns with the Golden Fleece One of his largest mines was at Las Medulas in León (Spain), where an Apulian red-figure calyx crater, c. In BC, seven long aqueducts channeled most of a large alluvial deposit. The mines of Roşia Montană in Transylvania were also very large and until recently they were still open pit. They have also mined smaller deposits in Britain, such as the hard rock and placer deposits at Dolaucothi. The various methods they used are well described by Pliny the Elder in his encyclopedia Naturalis Historia, written in the late 1st century AD.

Gold

176 During the Hajj to Mecca by Mansa Musa (ruler of the Mali Empire from 1312 to 1337) in 1324, he passed through Cairo in July 1324 and is said to have been accompanied by a caravan of camels carrying thousands of people and nearly a hundred camels wherever he went he took so much gold that it depressed the price in Egypt for over a decade.[54] A contemporary Arab historian commented: Until that year, gold was expensive in Egypt. The mithqal did not fall below 25 dirhams and was usually above it, but since then it has fallen in value and become cheaper and has remained cheap until now. The mithqal does not exceed 22 dirhams or less. This has been the state of affairs for some twelve years to the present day, due to the large amount of gold brought into and spent in Egypt [...] —Chihab Al-Umari,[55] Portuguese overseas expansion began in 1415 with the capture of Ceuta to control the gold trade that came from the desert. Although the caravan trade routes were diverted, the Portuguese continued to expand south along the coast, eventually buying gold directly (or less indirectly) from Africans in the Gulf of Guinea.

Ancient Greek crown decorated with gold, funerary or marriage material, 370–360 BC. From a tomb in Armmento, Campania

European exploration of the Americas was prompted in large part by reports of gold ornaments being exhibited in great abundance by Native American peoples, particularly in Central America, Peru, Ecuador, and Colombia. The Aztecs literally regarded gold as the product of the gods, calling it "God's excrement" (teocuitlatl in Nahuatl), and after Moctezuma was killed, most of this gold was shipped to Spain.[56] For the indigenous peoples of North America, however, gold was considered worthless and they saw far greater value in other minerals directly related to its utility, such as obsidian, flint, and slate.[57] Gold has played a role in Western culture as a motive for lust and corruption, as told in children's fairy tales like Rumpelstiltskin, where the farmer's daughter turns hay into gold when she gives up her son when she becomes a princess and steals. the goose that lays the golden eggs in Jack and the Beanstalk. The highest award at the Olympic Games is the gold medal. There is an old tradition of biting gold to test its authenticity. While this is certainly not a professional method of testing gold, the bite test was not intended to see if the coin was gold (90% of gold coins are quite strong) but rather to see if the coin was gold plated. A lead coin would be too soft and would therefore show teeth marks. Counterfeit gold coins were a common problem before 1932, so it was common to weigh a coin and also put it through a "counterfeit detector" slot (making a lead coin thicker would add weight, so why bother putting it through a push measured slot?) . Most establishments (particularly Western US saloons) would never accept a high value gold (or silver) coin until they weighed such an item. that all the gold ever refined would form a single cube 20 m (66 ft) on a side (equivalent to 8,000 m3). [] One of the main goals of alchemists was to create gold from other substances such as lead, presumably by interacting with a mythical substance called the Philosopher's Stone. Although they never succeeded in this attempt, the alchemists aroused interest in substances and thus laid the foundation for today's chemistry. Its symbol for gold was the circle with a dot in the center (☉), which was also the astrological symbol and ancient Chinese character for the sun.

Gold

177 Rumor has it that golden treasures have been found in various places after tragedies, such as the treasures of the Jewish Temple in the Vatican after the destruction of the Temple in AD 70 C., a gold stash on the Titanic, the Nazi gold train, after the Second World War world war. The Dome of the Rock on the grounds of the Temple of Jerusalem is covered in ultra-fine gold glaze. Wikipedia: Please clarify. The golden Sikh temple, the Harmandir Sahib, is a building covered in gold. Similarly, the emerald temple of Wat Phra Kaew Budha in Thailand has walls and ceilings decorated with golden statues. Some crowns of European kings and queens were made of gold, and gold had been used in the bridal crown since ancient times. An ancient Talmudic text from around AD 100 describes Rachel, the wife of Rabbi Akiba, asking for a "Golden Jerusalem" (crown). A Greek grave wreath made of gold was found around 370 BC. found in a tomb.

Occurrence Gold's atomic number of 79 makes it one of the highest atomic numbered naturally occurring elements. Like all elements with atomic numbers greater than iron, gold is believed to have formed from a supernova nucleosynthetic process, although a more recent theory suggests that it is formed from neutrons by the collision of stars. [58] In any case, the resulting explosions scattered dust containing metals (including heavy elements such as gold) into the region of space where it later condensed in our solar system and on Earth.[59] Since the earth was molten when it was formed, almost all of the gold present on earth sank into the core. Most of the gold found in the Earth's crust and mantle today was brought to Earth by asteroid impacts during later heavy bombardments.[60]

This 156 troy ounce (4.9 kg) nugget, known as the Mojave nugget, was found by a lone prospector using a metal detector in the Southern California desert.

On Earth, gold is found in minerals in rocks that date back to the Precambrian. [ ] Most commonly found as the native metal, usually in a solid solution of silver metal (i.e., as an alloy of gold and silver). These alloys typically have a silver content of 8-10%. Electrum is elemental gold with more than 20% silver. The color of Electrum ranges from silver-gold to silver depending on the silver content. The more silver, the lower the specific gravity. Native gold occurs as very small to microscopic particles embedded in the rock, usually along with quartz or sulfide minerals such as "fool's gold," which is a pyrite.[61] These are called vein deposits. The metal in its pristine state is also found in the form of free flakes, grains, or larger nuggets[] that have eroded from rocks and ended up in alluvial deposits called placer deposits. This free gold is always richer at the surface of the gold veins. seed

Gold

178 Gold sometimes occurs in combination with tellurium in the minerals calaverite, krennerite, nagyagite, petzite, and sylvanite, as well as the rare bismuth-maldonite (Au2Bi) and antimonide aurostibite (AuSb2). Gold is also found in rare alloys with copper, lead and mercury: the minerals auricupride (Cu3Au), novodneprite (AuPb3) and weishanite ((Au,Ag)3Hg2). Recent research suggests that microbes can sometimes play an important role in the formation of gold deposits, transporting and precipitating gold to form grains and nuggets that accumulate in alluvial deposits.[62] Another recent study claimed that water at fault lines evaporates during an earthquake and deposits gold. When an earthquake occurs, it moves along a fault line. Water often lubricates faults, fills fractures and landslides. About 10 kilometers below the surface, under incredible temperatures and pressures, the water carries high concentrations of carbon dioxide, silica and gold. During an earthquake, the fault channel suddenly opens wider. The water within the vacuum immediately evaporates, turning to steam, forcing the silica that forms the mineral quartz and gold out of the liquids and onto nearby surfaces.[63]

Relative sizes of an 860kg block of gold ore and the 30g of gold that can be mined from it. Toi Gold Mine, Japan.

Seawater The world's oceans contain gold. Measured gold concentrations in gold remaining after oxidation of a pyrite cube in the NE Atlantic and Pacific are 50 to 150 fmol/L, or 10 to 30 parts in hematite. Note the cubic shape of the cavity. 3 per quadrillion (about 10 to 30 g/km). In general, the gold concentrations for the Atlantic and Pacific samples are the same (~50 fmol/L) but less certain. The deep waters of the Mediterranean contain higher concentrations of gold (100-150 fmol/L) due to windblown dust and/or rivers. At 10 parts per quadrillion, Earth's oceans would contain 15,000 tons of gold.[64] These numbers are three orders of magnitude lower than those reported in the literature prior to 1988, indicating contamination issues with earlier data. Several people have claimed to be able to economically extract gold from seawater, but so far they have all been wrong or intentionally misled. Prescott Jernegan carried out a seawater gold scam in the United States in the 1890s. A British crook carried out the same scam in England in the early 1900s.[65] Fritz Haber (the German inventor of the Haber process) researched the extraction of gold from seawater to fund Germany's post-World War I reparations.[66] Commercially successful mining appeared possible based on published values ranging from 2 to 64 ppb gold in seawater. After analyzing 4,000 water samples, which averaged 0.004 ppb, it became clear that extraction would not be possible and the project was shelved.[67] No commercially viable mechanism for extracting gold from seawater has been identified. Gold synthesis is not economical and will not be in the foreseeable future.

Gold

179

Crystalline native gold specimens

native gold nuggets

"Golden Rope" of the Lena River, Sakha Republic, Russia. Size: 2.5 × 1.2 × 0.7cm.

Kristallines Gold aus der Zapata-Mine, Santa Elena de Uairén, Venezuela. Size: 3.7 × 1.1 × 0.4 cm.

Gold leaf from Harvard Mine, Jamestown, California, USA. Size 9.3 × 3.2 × > 0.1cm.

Production At the end of 2009 it was estimated that all gold ever mined was 165,000 tonnes.[2] This can be represented by a cube with a side length of about 20.28 meters. At $1,600 an ounce, Wikipedia: Clarify that 165,000 tons of gold would be worth $8.8 trillion. World production in 2011 was 2,700 tons, compared to 2,260 tons in 2008. Since the 1880s, South Africa has been the source of much of the world's gold supply, accounting for about 50% of all gold produced in South Africa's history. . Production in 1970 accounted for 79% of world supply and produced around 1,480 tons. In 2007, China (at 276 tons) overtook South Africa as the world's largest gold producer, the first time South Africa was not the largest since 1905.[68]

The entrance to an underground gold mine in Victoria, Australia

Mining Located in South Africa, the city of Johannesburg was founded as a result of the Witwatersrand Gold Rush which led to the discovery of some of the largest gold deposits the world has ever seen. The goldfields within the basin in the Free State and Gauteng provinces are extensive in direction and dip and require some of the world's deepest pure gold precipitation produced by mines in the aqua refining process, with the Savuka and TauTona mines being the deepest gold mines in the world today. at 3,777 m. The Second Boer War of 1899-1901 between the British Empire and the Afrikaner Boers was at stake, at least in part, over miners' rights and ownership of South Africa's gold wealth. Other important producers are the United States, Australia, Russia and Peru, as well as Ghana, Burkina Faso, Mali, Indonesia and Uzbekistan. Mines in South Dakota and Nevada provide two-thirds of the gold used in the United States.

Gold

180 In South America, the controversial Pascua Lama project aims to explore fertile grasslands in the high mountains of the Atacama Desert on the Chilean-Argentina border. It is currently estimated that about a quarter of the world's gold production comes from artisanal or small-scale mining.[69]

Prospecting During the 19th century there was always a gold rush when large gold deposits were discovered. The first documented discovery of gold in the United States was in 1803 at the Reed Gold Mine near Georgeville, North Carolina.[70] The first major gold discovery in the United States was in a small town in northern Georgia called Dahlonega.[71] Other gold digs took place in California, Colorado, Black Hills, Otago in New Zealand, Australia, Witwatersrand in South Africa and Klondike in Canada.

Extraction Extraction of gold is most economical in deposits that are large and easily mined. Ore grades as low as 0.5 mg/kg (0.5 parts per million, ppm) can be economical. Typical ore grades in open pit mines are 1 to 5 mg/kg (1 to 5 ppm); Ore grades in hard rock or underground mines are typically at least 3 mg/kg (3 ppm). Because ore grades of 30 mg/kg (30 ppm) are typically required before gold is visible to the naked eye, gold is invisible in most gold mines. Average 2007 mining and gold mine costs were approximately US$317/oz, but can vary widely depending on extraction method and ore grade; World mining production was 2,471.1 tons.[72]

Refining After the first extraction, gold is usually refined industrially, either by the Wohlwill process, which is based on electrolysis, or by the Miller process, i.e. chlorination in the melt. The Wohlwill process leads to higher purity, but is more complex and only applicable in small plants.[73][74] Other methods for analyzing and refining smaller amounts of gold include splitting and quarting, and cupellation, or refining methods based on the dissolution of gold in aqua regia.[75]

Synthesis of Other Elements Gold was synthesized from mercury by neutron bombardment in 1941, but the gold isotopes produced were all radioactive.[76] In 1924, a Japanese physicist, Hantaro Nagaoka, accomplished the same feat.[77] Currently, gold can be made in a nuclear reactor by irradiating platinum or mercury. Only the mercury isotope 196Hg, which occurs in natural mercury at an abundance of 0.15%, can be converted to gold by neutron capture and decay to 197Au after electron capture with slow neutrons. Other mercury isotopes are converted when irradiated with slow neutrons towards each other, or mercury isotopes are formed that decay to thallium. Using fast neutrons, the mercury isotope 198Hg, which makes up 9.97% of natural mercury, can be converted by fissioning a neutron and converting it to 197Hg, which then decays into stable gold. However, this reaction has a smaller activation cross section and can only be carried out with unmoderated reactors. It is also possible to emit several very high energy neutrons into the other isotopes of mercury at 197 Hg. However, these high-energy neutrons can only be produced by particle accelerators. Wikipedia: Please clarify.

Gold

181

Consumption About 50% of the world's gold production is used in jewellery, 40% in investments and 10% in industry. [citation needed] India is the world's largest consumer of gold, with Indians buying about 25% of the gold,[78] buying about 800 tons of gold each year, mostly for jewelry. India is also the largest importer of gold; In 2008 India imported around 400 tons of gold.[79] Indian households own 18,000 tons of gold, which accounts for 11% of the world's stocks and is valued at over US$950 billion.[80]

Consumption of gold jewelry by country in tons[81][82] Country

2009

2010

2011

2012

442,37

745,70

986,3

864

376,96

428,00

921,5

817,5

150,28

128,61

199,5

161

leaves

75.16

74.07

143

118

saudi arabian

77,75

72,95

69.1

58,5

Russia

60.12

67,50

76,7

81,9

United Arab Emirates

67,60

63,37

60,9

58.1

Egypt

56,68

53,43

47,8

Indonesia

41,00

32,75

52.3

United Kingdom

31,75

27h35

22.6

21.1

24.10

21.97

19.9

Japan

21.85

18h50

-30,1

7.6

South Korea

18.83

15.87

15,5

12.1

Vietnam

15.08

14.36

100,8

Thailand

7.33

6.28

107.4

80,9

390,4

393,5

India Greater China United States

Other countries in the Persian Gulf

Total Other countries Total world

1508,70 1805,60 251,6 1760,3

254,0

2059,6 3487,5 3163,6

Pollution Gold production is associated with a contribution to hazardous environmental pollution.[83] The ore, which typically contains less than 1 ppm metallic gold, is ground and mixed with sodium cyanide or mercury to react with the gold in the ore and separate the gold. Cyanide is a highly toxic chemical that can kill living things if exposed to traces. There have been numerous releases of cyanide[84] from gold mines in both developed and developing countries, killing marine life in large parts of the affected rivers. Environmentalists view these events as major environmental disasters.[85][86] When mercury is used in gold production, the smallest amounts of mercury compounds get into water and cause heavy metal pollution. Mercury can then enter the human food chain in the form of methylmercury. Mercury poisoning causes irreversible damage to brain function and severe intellectual disability in humans. Thirty tons of used ore are discarded to produce 1 ounce (28 g) of gold.[87] Gold ore deposits are the source of many heavy elements such as cadmium, lead, zinc, copper, arsenic, selenium and mercury. When the sulfide ores from these deposits are exposed to air and water, the sulfide is converted to sulfuric acid, which is

Gold

182 in turn dissolves these heavy metals and facilitates their transfer to surface and ground water. This process is known as acid mine drainage. These gold ore deposits are highly hazardous long-term waste second only to nuclear waste sites.[87] Gold mining is also an energy-intensive industry, extracting ore from deep mines and crushing the large amount of ore for further chemical extraction, which requires 25 kWh of electricity per gram of gold produced.[88]

Chemistry Although gold is the noblest of the noble metals, [89] [90] it still forms many different compounds. The oxidation state of gold in its compounds ranges from -1 to +5, but Au(I) and Au(III) dominate its chemistry. Au(I), the so-called aurorion, is the most common oxidation state in soft ligands such as thioethers, thiolates, and tertiary phosphines. Au(I) compounds are typically linear. A good example is Au(CN)2−, the soluble form of gold found in mining. Interestingly, aurora water complexes are rare. Binary gold halides such as AuCl form zigzag polymer chains, again with linear coordination in Au. Most gold-based drugs are derived from Au(I).[91]

Gold(III) chloride solution in water

Au(III) (auric) is a common oxidation state and is exemplified by gold(III) chloride, Au2Cl6. The centers of the gold atoms in Au(III) complexes, as in other d8 compounds, are usually planar squares with chemical bonds of both covalent and ionic character. Aqua regia, a 1:3 mixture of nitric acid and hydrochloric acid, dissolves gold. Nitric acid oxidizes metal to +3 ions, but only in minute amounts not normally detectable in pure acid due to the chemical equilibrium of the reaction. However, the ions are unbalanced by hydrochloric acid, forming AuCl4 ions or chloroauric acid, allowing further oxidation. Some free halogens react with gold.[92] Gold also reacts in alkaline potassium cyanide solutions. It forms an amalgam with mercury.

Less Common Oxidation States The less common oxidation states of gold include -1, +2, and +5. The −1 oxidation state occurs in compounds containing the anion Au−, called aurides. For example, cesium aureus (CsAu) crystallizes into the cesium chloride motif.[] Other aurides include those of Rb+, K+, and tetramethylammonium (CH3)4N+.[93] Gold has the highest Pauling electronegativity of any metal with a value of 2.54, making the auride anion relatively stable. Gold(II) compounds are generally diamagnetic with Au-Au bonds such as [Au(CH2)2P(C6H5)2]2Cl2. Evaporation of a solution of Au(OH) 3 in concentrated H 2SO 4 produces red crystals of gold(II) sulfate, Au(SO). Originally thought to be a mixed-valence compound, it has been shown to contain 2 4 2 Au4+ cations [94][95] 2. A notable and legitimate gold(II) complex is the tetraxene gold(II) cation, which contains xenon as a Ligand found in [AuXe4](Sb2F11) 2. [96] Gold pentafluoride, along with its derived anion AuF-6 and its difluoride complex gold heptafluoride, is the only example of gold(V), the highest observed oxidation.

Gold

183 states.[97] Some gold compounds exhibit aurophilic bonding, which describes the tendency of gold ions to interact over distances too long to be a traditional Au-Au bond but shorter than van der Waals bonds. The interaction is estimated to be comparable in strength to that of a hydrogen bond.

Compounds with Mixed Valences There are numerous compounds with well-defined groups.[93] In these cases, gold is in a fractional oxidation state. A representative example is the octahedral species {Au(P(C6H5)3)}62+. Gold chalcogenides, like gold sulfide, have equal amounts of Au(I) and Au(III).

Toxicity Pure metallic (elemental) gold is not toxic or irritating by ingestion[98] and is sometimes used in the form of gold leaf as food decoration. Metallic gold is also part of the alcoholic beverages Goldschläger, Gold Strike and Goldwasser. Metallic gold is approved as a food additive in the EU (E175 in Codex Alimentarius). Although the gold ion is toxic, the acceptance of metallic gold as a food additive rests on its relative chemical inertness and its resistance to corrosion or conversion to soluble sales (gold compounds) by any known chemical processes that would be found in its being. Body. Soluble compounds (gold salts) such as gold chloride are toxic to the liver and kidneys. Conventional gold cyanide salts such as potassium gold cyanide used in gold plating are toxic due to their cyanide and gold content. There have been rare cases of fatal gold poisoning with potassium gold cyanide.[99][100] Gold toxicity can be ameliorated by chelation therapy with an agent such as dimercaprol. Gold metal was named Allergen of the Year in 2001 by the American Contact Dermatitis Society. Gold contact allergies mainly affect women.[101] Despite this, gold is a relatively weak contact allergen compared to metals such as nickel.[102]

Price Like other precious metals, gold is measured in fines and grams. When associated with other metals, the term carat or carat is used to indicate the purity of the gold present, with 24k pure gold and lower grades being proportionally smaller. The purity of a gold bar or coin can also be expressed as a decimal number from 0 to 1, known as thousandths of fineness, with 0.995 being very pure. Gold prices are determined by trading in the gold and derivatives markets, the history of gold prices from 1960 to 2011, but a procedure known as the London Gold Fixing, which originated in September 1919, provides an industry diary for reference prices. Overnight binding was introduced in 1968 to provide a price when US markets are open.[103] Historically, gold coins have been widely used as currency; When paper money was introduced, it was usually a receipt redeemable for gold coins or bullion. On a monetary system known as the gold standard, there was a certain weight of gold

Gold

184 given the name of a currency unit. For a long time the US government set the value of the US dollar as $20.67 per troy ounce ($664.56/kg), but in 1934 the dollar was valued at $35.00 per troy ounce ($1125.27 /kg) devalued. By 1961, this price was becoming difficult to maintain, and a group of American and European banks agreed to manipulate the market to prevent further currency devaluations amid increased demand for gold.[104] On March 17, 1968, due to economic circumstances, the gold pool collapsed and a two-tier pricing system was introduced, with gold still being used to settle international bills at the former $35.00 per troy ounce (US$1.13/g), but the price of gold in the private market was allowed to fluctuate; This two-tier pricing system was abandoned in 1975 when gold prices were allowed to find their level on the open market. Central banks still hold historical gold reserves as a store of value, although levels have generally fallen. The largest gold deposit in the world is that of the US Federal Reserve in New York, which owns about 3%[] of all gold ever mined and a 1-piece gold bar melted in Switzerland. kg has the US Bullion Depository of similar cargo at Fort Knox. In 2005, the World Gold Council estimated that total world gold supply was 3,859 tons and demand was 3,754 tons, resulting in a surplus of 105 tons.[105] Around 1970 the price began to rise sharply[106] and since 1968 the price of gold has fluctuated widely, from a high of $850/oz ($27,300/kg) on January 21, 1980 to a low of $252.90/oz ($8,131/kg) on June 21, 1999 (London Gold Fixing).[107] The period from 1999 to 2001 marked the "brown bottom" after a 20-year bear market.[108] Prices have risen rapidly since 2001, but the 1980 high was not broken until January 3, 2008, when a new high of $865.35 per troy ounce was set. $32,900/kg). ).[] In late 2009, the gold markets experienced renewed bull momentum due to increased demand and the weakening of the US dollar. Gold hit a new closing high of $1,217.23 on December 2, 2009.[109] Gold rallied again, hitting new highs in May 2010 after the European Union debt crisis prompted increased buying of gold as a safe haven asset.[110][111] On March 1, 2011, gold hit a new all-time high of $1,432.57, building on investor concerns about ongoing unrest in North Africa and the Middle East.[112] Since April 2001, the price of gold has more than quintupled against the US dollar, hitting a new all-time high of $1,913.50 on August 23, 2011,[113] prompting speculation that this long market has ended and a bull market has followed. returned.[114]

Symbolism Great human achievements are often rewarded with gold, in the form of gold medals, gold trophies, and other awards. Winners of sporting events and other qualifying competitions are usually awarded a gold medal. Many awards, such as the Nobel Prize, are also made of gold. Other awards and prize statues are depicted in gold or gilded (such as the Academy Awards, Golden Globes, Emmy Awards, Palme d'Or, and British Academy Film Awards). Aristotle used the symbolism of gold in his Ethics when referring to the bullion in the Emperor's casino in Macau, now commonly known as the golden mean. Likewise, gold is associated with perfect or divine principles, as in the case of the golden ratio and the golden rule.

Gold

185 Gold is also associated with the wisdom of aging and fertility. The fiftieth wedding anniversary is golden. Our precious final years are sometimes referred to as the "golden years." The pinnacle of a civilization is referred to as the "golden age." In some forms of Christianity and Judaism, gold has been associated with both holiness and evil. In the book of Exodus, the golden calf is a symbol of idolatry, while in the book of Genesis, Abraham is described as rich in gold and silver and Moses was assigned to cover the mercy seat of the Ark of the Covenant. with pure water. prayed In Byzantine iconography, the halos of Christ, Mary, and Christian saints are often gilded. Medieval kings were sworn in under the signs of holy oil and a golden crown, the latter symbolizing the eternally shining light of heaven and thus the divinely inspired authority of a Christian king [citation needed]. According to Christopher Columbus, those who had some gold possessed something of great value on earth and substance to carry even souls to paradise.[115] Wedding rings have long been made of gold. It is durable and unaffected by time and can aid in the ring's symbolism for perpetual vows to God and/or the sun and moon and the perfection that marriage signifies. In Orthodox Christian wedding ceremonies, the couple is adorned with a gold crown (although some opt for wreaths) during the ceremony, an amalgamation of symbolic rites. In popular culture, gold has many connotations, but it is usually associated with terms like good or great, as in the phrases: "He has a heart of gold", "This is gold!", "Golden moment", "So du It's golden!" and "golden child". Gold continues to assert its place as a symbol of wealth and thus in many societies of success.

State Emblem In 1965, the California Legislature designated gold as "the mineral and mineralogical emblem of the State."[116] In 1968, the Alaska Legislature named gold "the official state mineral."[117]

References [1] Magnetic Susceptibility of Elements and Inorganic Compounds (http://www-d0.fnal.gov/hardware/cal/lvps_info/engineering/elementmagn.pdf) in [2] World Gold Council FAQ (http://www .gold.org/investment/ why_how_and_where/ faqs/ #q022). www.gold.org [3] http://www. bb co. uk/news/science-environment-14827624 [4] http://www. daily science. com/releases/2011/09/110907132044.htm [5] http://www. Yes. rochester edu/ ees119/ reading2. pdf [6] http://www. Huffington Post. com/2011/09/10/Meteorschauer-oro_n_955448. html [7] http://www. Nature. com/ nature/ diary/ v477/ n7363/ complete/ nature10399. html#/ access [8] http:// Superiormining. com/properties/south africa/mangalisa/geology/ [9] http://articles. To sue. Harvard. edu/ / complete/ 1997M%26PS. . . 32. . . 71T/ 0000071. 000. html Actual size of the Vredefort Structure: Implications for the Geological Evolution of the Witwatersrand Basin [10] http://www. cosmo magazine. com/news/2101/ meteor-craters-may-contain-unexplored-riches Meteor craters can contain unexplored-riches. Cosmos Magazine 2008 [11] http://www. pure science. com/ science/article/pii/ 004019519090089Q [12] Oxford English Dictionary [13] Hesse, R W. Jewelrymaking Through History: An Encyclopedia (http://books.google.com/books?id=DIWEi5Hg93gC& pg=PA103), Greenwood Publishing Group, 2007 ISBN 0313335079 [14] Supporting references: "Shining Dawn" Google-scholar (http://academic.google.5&as_sdtp=) & Google-books (https://www.google.com/search?q =Au+ -+ gold+ etymology& btnG=search+ books& tbm=bks& tbo=1#hl=en& tbo=1& tbm=bks& sclient= psy-ab& q=etymology+ of+ Au+ chemical+ symbol+ bright+ sunrise& oq=etymology+ of+ Au+ chemical+ symbol+ bright+ dawn& aq =f&aqi=&aql=&gs_l=serp 12 ... 42262 56773 2 58184 29 26 0 0 0 0 972 6330 0j15j8j1j0j1j1 26 0 ... 0 . 0. eiq2tKECEYY& pbx=1& bav=on.2, o.r_gc.r_pw.r_cp.r_qf.,cf.osb&fp=d95a9e9054f7730a&biw=1280&bih=897) Retrieved 7 June 2012 [15] Christie, A. and Brathwaite, R. Mineral Commodity Report (http://scholar user content or do g oogle.com/scholar ?q=cache:f2hCjL2EyqUJ:scholar. Google. com/ + gulth& hl=en& as_sdt=0.5), Institute of Geological and Nuclear Sciences Ltd - Accessed 7 June 2012

Gold

186 [16] University of Notre Dame Latin Dictionary (http://www.archives.nd.edu/cgi-bin/lookup.pl?stem=Aurum&ending=) Accessed 7 June 2012 [17] Maspero, G, and Sayce, AH (1910) The Dawn of Civilization: Egypt and Chaldæa (http://archive.org/details/dawnofcivilizati00masp) [18] Crooks, G R; Ingersley, C F and Schem, A J. A new Latin-English school lexicon: based on Dr. C.F. Ingerslev (http://books.google.com/books?id=gfQsAAAAAYAAJ& pg=PA113), J.B. Lippincott, 1861 Accessed 7 June 2012 [32] World Gold Council, Jewelery Technology, Jewelery Alloys (http://www.utilegold.com/jewelery_technology/colours/colour_alloys/) [35] Mortier, Tom. An Experimental Study on the Preparation of Gold Nanoparticles and their Properties (https://lirias.kuleuven.be/bitstream/1979/254/2/thesis_finaal.pdf), doctoral thesis, University of Leuven (May 2006) [ 45 ] Guinness Book of World Records 2008 [47] Kodak (2006) Toning of Black and White Materials (http://www.kodak.com/global/en/professional/support/techPubs/g23/g23.pdf). Technical Data/G-23 Reference Sheet, May 2006. [54] Mansa Musa (http://blackhistorypages.net/pages/mansamusa.php). Black History Pages [57] Sierra Nevada Virtual Museum (http://www.sierranevadavirtualmuseum.com/docs/galeries/history/culture/shadows.htm). Virtual Museum of the Sierra Nevada. Accessed 05/04/2012. [62] This is a PhD thesis conducted by Frank Reith at the Australian National University and published in 2004. [65] Plazak, Dan A Hole in the Ground with a Liar at the Top (Salt Lake: Univ. of Utah Press, 2006) ISBN 0-87480-840-5 (includes a chapter on seawater gold strokes) [77] A Miethe, "The decay of the mercury atom", Naturwissenschaften, 12(1924): 597-598 [82] http://www. prayed org/investment/research/regular_reports/ gold_demand_trends/ [83] Summit Declaration, Peoples Gold Summit, San Juan Ridge, California, June 1999 (http://www.pdfcookie.com/doc/82418790/Goldproduction-and-your-environmental -A hit). Scribd.com (2012-02-22). Accessed 05/04/2012. [84] Cyanide spill from a gold mine compared to the Chernobyl nuclear disaster (http://www.deseretnews.com/article/810435/Cyanide-spill-compared-to-Chernobyls---N-disaster.html). Deseretnews.com (2000-02-14). Accessed 05/04/2012. [85] The Death of a River (http://news.bbc.co.uk/2/hi/europe/642880.stm). BBC News (2000-02-15). Accessed 05/04/2012. [86] Cyanide spill second only to Chernobyl (http://www.abc.net.au/am/stories/s98890.htm). abc.net.au 11 February 2000. Accessed 04/05/2012. [87] Behind Gold's Glitter, Torn Lands, and Pointy Questions (http://www.latrobefinancialmanagement.com/Research/Commodities/Behind Gold's Glitter NYTimes Piece.pdf), New York Times, October 24, 2005. (PDF) . Accessed 05/04/2012. [93] Holleman, A.F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5. [101] MacNeil, Jane Salodof The henna tattoo ingredient is the allergen of the year. (Clinical rounds). 3 January 2006. [107] Kitco.com (http://kitco.com/LFgif/au75-pres.gif), Gold–London PM Fix 1975–present (GIF), accessed 22 July 2006. [116 ] California Government Code Selection 420-429.8 (http://www.leginfo.ca.gov/cgi-bin/displaycode?section=gov&group=00001-01000&file=420-429.8) (see § 425.1) [117] Alaska Statutes ( http://www.legis.state.ak.us/cgi-bin/folioisa.dll/stattx08/query=*/doc/{@17998}?) (see §44.09.110)

External Links • Chemistry in Your Element Podcast (http://www.rsc.org/chemistryworld/podcast/element.asp) (MP3) from Chemistry World: Gold by the Royal Society of Chemistry (http://www. rsc.org ) /images/ CIIE_Gold_48k_tcm18-118269.mp3) www.rsc.org • Gold (http://www.periodicvideos.com/videos/079.htm) in the Periodic Table of Videos (University of Nottingham) • Got Gold Book 1898 (http://www.lateralscience.co.uk/gold/auriferous.html), www.lateralscience.co.uk • White Paper on Gold Extraction and Mining (http://web.archive.org/web/20080307000911/ http://www.epa.gov/epaoswer/other/mining/techdocs/gold.pdf), www.epa.gov • Picture in the element collection by Heinrich Pniok (http://www.pniok.de/au . htm ), www.pniok.de • The Art of Pre-Columbian Gold: The Jan Mitchell Collection (http://libmma.contentdm.oclc.org/cdm/compumbleobject/collection/p15324coll10/id/119785/rec/1) , a catalog of the Metropolitan Museum of Art exhibition (fully available online as PDF)

Eisen

187

Ferro Ferro Fe 26

Manganese ← Iron → Cobalt ↑

Fe ↓ Ru Iron on the Periodic Table Shiny metallic appearance with a greyish tint

Iron Spectral Lines General Properties Name, Symbol, Number

Ferro, Fe, 26

pronunciation

/ˈaɪ.ərn/

item category

transition metal

group, period, block

8, 4, d

standard atomic weight

55.845(2)

Eisen

188 Electronic configuration

[Ar] 3d6 4s2 2, 8, 14, 2

discovery of history

before 5000 BC Chr. C. Physical properties

Phase

fest

Density (near room temperature)

7,874 g·cm−3

Density of the liquid in m.p.

6,98 g·cm−3

fusion point

1811K, 1538°C, 2800°F

boiling point

3134K, 2862°C, 5182°F

heat of fusion

13.81 kJ·mol-1

heat of vaporization

340 kJ·mol-1

molar heat capacity

25.10 J mol-1 K-1 vapor pressure

P (Pa)

100

1 k

10 thousand 100 thousand

at T (K) 1728 1890 2091 2346 2679 3132 Atomic properties [1]

[2]

oxidation states

6, 5, 4, 3, 2, 1, -1, -2 (amphoteres Oxid)

electronegativity

1.83 (Pauling Scale)

Ionization energies (more)

1st: 762.5 kJ mol-1 2nd: 1561.9 kJ mol-1 3rd: 2957 kJ mol-1

Atomic func

126 S. m.

covalent ray

132±3 (low idle), 152±6 (high idle) pm Miscellaneous

Eisen

189 crystal structure

centered cubic body

a = 286.65 pm; face-centered cubic

Between 1185-1667K Magnetic Sort

ferromagnetic 1043 K

Electrical resistance

(20 °C) 96,1 nΩ·m

thermal conductivity

80,4 W·m−1·K−1

thermal expansion

(25 °C) 11,8 µm·m−1·K−1

Speed of Sound (thin bar)

(r.) (electrolytic) 5120 m s-1

modulus of elasticity

211 GPa

Schneidmodul

82 GPa

Volumenmodul

170 GPa

poison ratio

0,29

Mohs hardness

Dureza Vickers

608 MPa

Brinell hardness

490 MPa

CAS registration number

7439-89-6 Most stable isotopes Main article: Iron isotopes

You are so

THE

5,8%

sin

zb zb

Eisen 91,72 %

56 57

trust

2,2%

Fe 0,28 %

half-life

DM OF (MeV)

>3.1 × 1022 years β+β+ 2.73 years

0,6800

0,231

Minnesota

Fe is stable with 30 neutrons

Fe is stable with 31 neutrons

Fe is stable with 32 neutrons

sin

44,503 diam

b−

1.565

sin

2.6 × 106 years

b−

3.978

zb zb

was was

Iron is a chemical element with the symbol Fe (Latin: ferrum) and atomic number 26. It is a first transition series metal. It is the most common element (by mass) that makes up planet Earth as a whole, making up much of the Earth's outer and inner core. It is the fourth most abundant element in the earth's crust. Very frequent presence of iron.

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190 on rocky planets like Earth is due to its abundant production as a result of fusion in massive stars, where the production of nickel-56 (which decays into the more common iron isotope) is the final reaction of nuclear fusion. it is exothermic. . This makes radioactive nickel the last element to be produced before a supernova collapse leads to explosive events that disperse this iron-precursor radionuclide abundantly in space. Like other Group 8 elements, iron occurs in a variety of oxidation states, from -2 to +6, although +2 and +3 are the most common. Elemental iron is found in meteorites and other low-oxygen environments, but it reacts with oxygen and water. Fresh iron surfaces appear lustrous silver-grey, but will oxidize in normal air to form hydrated iron oxides, commonly known as rust. Unlike many other metals that form passivation oxide layers, iron oxides occupy more volume than ferrous metal and therefore iron oxides flake off, exposing fresh surfaces to corrosion. Metallic iron has been used since ancient times, although copper alloys, which have lower melting temperatures, were used for the first time in history. Pure iron is soft (softer than aluminum) but cannot be melted. Impurities from the casting process, such as As carbon, the material is significantly hardened and strengthened. A certain amount of carbon (between 0.002% and 2.1%) produces steel, which can be up to 1,000 times harder than pure iron. Crude metallic iron is produced in blast furnaces, where coke reduces the ore into high-carbon pig iron. Additional oxygen refining reduces the carbon content to the right ratio for steelmaking. Low carbon steels and alloys of iron with other metals (alloy steels) are by far the most common metals in industrial use due to their wide range of desirable properties and abundance of iron. Iron chemical compounds, which include ferrous and ferric iron compounds, have many uses. Iron oxide mixed with aluminum powder can be ignited to produce a thermite reaction, used for welding and cleaning minerals. It forms binary compounds with halogens and chalcogens. Among its organometallic compounds is ferrocene, the first sandwich compound discovered. Iron plays an important role in biology by forming complexes with molecular oxygen in hemoglobin and myoglobin; both of these compounds are common oxygen transport proteins in vertebrates. Iron is also the metal used in the active site of many important redox enzymes involved in cellular respiration and oxidation and reduction in plants and animals.

Properties Mechanical properties Characteristic tensile strength (TS) and Brinell hardness (BH) values of various forms of iron.[][] Material

TS BH (MPa) (Brinell)

iron whiskers

11000

Formed Steel (Hardened)

2930

850–1200

maraging steel

2070

600

bainitic steel

1380

400

pearlitic steel

1200

350

cold worked iron

690

200

small-grained iron

340

100

Iron with carbon 140

Pure monocrystalline iron 10

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191 The mechanical properties of iron and its alloys can be evaluated using a variety of tests, including the Brinell test, the Rockwell test, and the Vickers hardness test. Iron data is so consistent that it is often used to calibrate measurements or compare tests.[][3] However, the mechanical properties of iron are significantly affected by sample purity: the pure individual iron crystals are used for research purposes in fact softer than aluminum,[] and the purest manufactured iron (99.99%) has a hardness of 20-30 Brinell.[4] An increase in the carbon content of the iron initially causes a correspondingly significant increase in the hardness and tensile strength of the iron. The maximum hardness of 65 Rc is reached at a carbon content of 0.6%, but this results in a metal with low tensile strength.[5]

Phase and allotrope diagram Iron is an example of allotropy in a metal. There are at least four allotropic forms of iron known as α, γ, δ, and ε; at very high pressures there is some controversial experimental evidence for a stable β-phase at very high pressures and temperatures. crystal structure. As it cools further, its crystal structure changes to face-centered cubic (fcc) at 1394 °C when it is known as γ-iron or austenite. At 912°C the crystal structure reverts to bcc as forms of α-iron or ferrite, and at 770°C (Curie point, Tc) iron becomes magnetic. When the iron goes through the Curie temperature there is no change in the structure of the crystal, but there is a change in the "domain structure" where each domain contains iron atoms with a specific electron spin. In unmagnetized iron, all electron spins of atoms within a domain have the same direction; adjacent domains point in multiple directions and hence the low-pressure phase diagram of pure iron cancels out. In magnetized iron, the electronic spins of all domains are aligned, so the magnetic effects of neighboring domains are mutually reinforcing. Although each domain contains billions of atoms, they are very small, about 10 micrometers in diameter. which is also known as ε-iron; the higher temperature γ-phase also converts to ε-iron, but at a higher pressure. The β-phase, if present, would occur at pressures of at least 50 GPa and temperatures of at least 1500 K; it is believed to have an orthorhombic or double hcp structure. [ ] Iron is of great importance when mixed with other metals and carbon to form steel. There are many types of steels, all with different properties, and understanding the properties of iron allotropes is critical to producing high-quality steels. Alpha-iron, also called ferrite, is the most stable form of iron at normal temperatures. It is a fairly soft metal that can only dissolve a small concentration of carbon (no more than 0.021% by mass at 910 °C).[6] Above 912 °C and up to 1400 °C, α-iron undergoes a phase transition from the bcc to the fcc configuration of γ-iron, also called austenite. This is just as soft and metallic, but can dissolve significantly more carbon (up to 2.04% by mass at 1146 °C). This form of iron is used in the type of stainless steel used in the manufacture of cutlery and equipment for hospitals and hospitality establishments. [ ] The high pressure phases of iron are important as end member models for the solid parts of planetary cores. It is generally believed that the Earth's inner core consists essentially of an iron-nickel alloy with an ε (or β) structure.

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192 The melting point of iron is well defined experimentally for pressures up to about 50 GPa. For higher pressures, various studies have placed the triple point of the γ-ε fluid at pressures differing by tens of gigapascals and have found differences of more than 1000 K for the melting point. In general, computer simulations of iron melting molecular dynamics and shock wave experiments suggest higher melting points and a much steeper slope of the melting curve than static experiments performed in iron cells. Diamond Anvil.[]

Isotopes Natural iron consists of four stable isotopes: 5.845% 54Fe, 91.754% 56Fe, 2.119% 57Fe and 0.282% 58Fe. Of these stable isotopes, only 57Fe has nuclear spin (-1/2). The nuclide 54Fe is predicted to undergo double beta decay, but this process has never been observed experimentally for these nuclei, and only the lower half-life limit has been established: t1/2 > 3.1 × 1022 years. 60

Fe is an extinct radionuclide with a long half-life (2.6 million years).[7] It does not occur on Earth, but its ultimate decay product is the stable nuclide nickel-60. Much of the previous work measuring the isotopic composition of Fe has focused on determining changes in 60Fe due to processes accompanying nucleosynthesis (i.e. meteorite studies) and mineral formation. However, in the last decade, advances in mass spectrometry technology have enabled the detection and quantification of small natural variations in the proportions of stable iron isotopes. Much of this work has been done by Earth and planetary scientists, although applications to biological and industrial systems are beginning to emerge.[8] The most abundant iron isotope, 56Fe, is of particular interest to nuclear scientists because it is the most common endpoint of nucleosynthesis. It is often erroneously referred to as the isotope with the highest binding energy, a distinction that actually belongs to nickel-62.[9] Since 56Ni is easily produced from lighter nuclei in the alpha process in supernova nuclear reactions (see silicon combustion process), nickel-56 (14 alpha particles) is the endpoint of fusion chains within extremely hot stars much more energy required. This nickel-56, which has a half-life of about 6 days, is abundantly produced in these stars but soon decays through two consecutive positron emissions within the supernova decay products in the gas cloud. Supernova remnant, first in radioactive cobalt-56 and then in stable iron-56. This last nuclide is therefore common in the Universe compared to other stable metals of roughly the same atomic weight. In the phases of the Semarkona and Chervony-Kut meteorites, a correlation was found between the concentration of 60Ni, the daughter product of 60Fe, and the abundance of stable iron isotopes, proving the existence of 60Fe at the time of formation. Sun. System. It is possible that the energy released from the decay of 60Fe, together with the energy released from the decay of the radionuclide 26Al, contributed to the remelting and differentiation of asteroids after their formation 4.6 billion years ago. The abundance of 60Ni in extraterrestrial material could also provide more information about the origin of the solar system and its early history.[10] The nuclei of iron atoms have some of the highest binding energies per nucleus, surpassed only by the nickel isotope 62 Ni. This is created by nuclear fusion in stars. Although a small additional energy gain can be gained from the synthesis of 62Ni, the conditions in stars are not suitable for this process. The element distribution on Earth strongly favors iron over nickel, and presumably also in the production of supernova elements.[11] Iron-56 is the heaviest stable isotope produced by the alpha process in stellar nucleosynthesis; Elements heavier than iron and nickel require a supernova to form. Iron is the most abundant element in the cores of red giants and the most abundant metal in iron meteorites and in the dense metallic cores of planets like Earth.

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Nucleosynthesis Iron is produced by extremely large and extremely hot stars (over 2.5 billion Kelvin) through the process of burning silicon. It is the heaviest stable element made in this way. The process begins with the second largest stable nucleus produced by burning silicon, which is calcium. A stable calcium core fuses with a helium core, creating unstable titanium. Before the titanium decays, it can fuse with another helium nucleus, creating unstable chromium. Before the chromium breaks down, it can fuse with another helium nucleus, creating unstable iron. Before the iron decays, it can fuse with another helium nucleus, creating unstable nickel-56. Each subsequent smelting of nickel-56 consumes energy instead of producing it; Therefore, after producing nickel-56, the star does not produce enough energy to prevent the core from collapsing. Eventually, nickel-56 breaks down into unstable cobalt-56, which in turn breaks down into stable iron-56. When the core of the star collapses, a supernova occurs. Supernovae also produce additional forms of stable iron through the r-process.

Occurrence Planetary Occurrence Iron is the sixth most abundant element in the universe and the most common refractory element. [ ] It forms as the final exothermic stage of stellar nucleosynthesis through the melting of silicon in massive stars. Natural or metallic iron is rarely found on the earth's surface because it tends to rust, but its oxides are ubiquitous and constitute the most important minerals. Although it makes up about 5% of the earth's crust, the inner and outer core is believed to be composed mostly of a iron-nickel alloy, which makes up 35% of the earth's total mass. Consequently, iron is the most abundant element on earth, but iron meteorites of similar composition are the fourth most abundant element in the earth's crust.[12][13] Most of the iron in the inner and outer core of the crust is found in association with oxygen in the form of iron oxide minerals such as hematite and magnetite. Large iron deposits are found in banded iron formations. These geological formations are a rock type composed of repeated thin layers of iron oxides, magnetite (Fe3O4) or hematite (Fe2O3) alternating with iron-poor shale and chert bands. The iron band formations were deposited between 3700 [14] million years and 1800 [15] million years [14][15]. % iron) and kamacite (90-95% iron). Although rare, iron meteorites are the most important naturally occurring form of metallic iron on Earth's surface.[16] Mössbauer spectroscopy showed that the red color of the Martian surface originates from an iron oxide-rich regolith.[17] Stocks used in society According to the International Resource Panel's report 'Metal Stocks in Society', the world per capita stock of iron used in society is 2200 kg. Much of this occurs in more developed countries (7,000 to 14,000 kg per capita) than in less developed countries (2,000 kg per capita).

chemistry and compounds

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Oxidation state -2

representative connection

Dinatriumtetracarbonylferrat (Collmans Reagenz)

−1 0

Eisenpentacarbonyl

Cyclopentadienyleisendicarbonyldimer ("Fp2")

iron sulfate, ferrocene

Eisenchlorid, Ferroceniumtetrafluorborat

barium ferrate (IV)

5 6

Potassium swings

Iron mainly forms compounds in the +2 and +3 oxidation states. Traditionally, ferrous compounds are referred to as ferrous iron and ferric compounds as ferric iron. Iron also occurs in higher oxidation states, an example is purple potassium ferrate (K2FeO4), which contains iron in its +6 oxidation state. Iron(IV) is a common intermediate in many biochemical oxidation reactions.[18][] Numerous organometallic compounds contain formal oxidation states of +1, 0, -1, or even -2. Oxidation states and other bonding properties are commonly determined using the Mössbauer spectroscopy technique.[19] There are also many mixed-valence compounds containing iron(II) and iron(III) centers, such as magnetite and Prussian blue (Fe4(Fe[CN]6)3).[] The latter is used as “traditional blue”. " in the plans.[20] The iron compounds produced industrially on the largest scale are ferrous sulfate (FeSO4 7H2O) and ferric chloride (FeCl3). The former is one of the most readily available sources of ferrous iron ) compounds, but is less stable to air oxidation than Mohr's salt ((NH4)2Fe(SO4)2 6H2O). Iron(II) compounds tend to oxidize to ferric(III) compounds in air. [ ] Im Unlike many other metals, iron does not form amalgams with mercury, and as a result mercury is sold in standard 34 kg iron vials.[21]

binary connections

Ferric chloride hydrate, also known as ferric chloride

Iron reacts with atmospheric oxygen to form various oxide and hydroxide compounds; the most common are iron(II,III) oxide (Fe3O4) and iron(III) oxide (Fe2O3). Iron(II) oxide also exists, although it is unstable at room temperature. These oxides are the main ores for iron production (see Bloomery and Blast Furnace). They are also used in the manufacture of ferrites, magnetic storage media useful in computers, and pigments. The best-known sulfide is iron pyrite (FeS2), also known as fool's gold because of its golden luster. [ ] Binary ferrous and ferric halides are well known, with the exception of ferric iodide. Iron halides are generally formed by treating metallic iron with the corresponding binary haloacid to give the corresponding hydrated salts. most common are:

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195 2 Fe + 3 X2 → 2 FeX3 (X = F, Cl, Br)

Coordination and Organometallic Compounds Several cyanide complexes are known. The best-known example is Prussian blue, (Fe4(Fe[CN]6)3). Potassium ferricyanide and potassium ferrocyanide are also known; The formation of Prussian blue when Prussian blue reacts with iron(II) or iron(III) forms the basis of a "wet" chemical test. Prussian blue is also used as an antidote for radioactive thallium and cesium poisoning. Prussian Blue can be used on blue clothing to correct the yellow cast left by iron salts in the water. Several carbonyl compounds of iron are known. The most important iron(0) compound is iron pentacarbonyl, Fe(CO)5, which is used to produce iron carbonyl powder, a highly reactive form of metallic iron. Thermolysis of iron pentacarbonyl gives the trinuclear cluster triferrododecacarbonyl. Collman's reagent, disodium tetracarbonyl ferrate, is a useful reagent in organic chemistry; Contains iron in the -2 oxidation state. Cyclopentadienilirondicarbonyl dimer contains iron in the rare +1 oxidation state.[24] Ferrocene is an extremely stable complex. The first sandwich compound contains an iron(II) center with two cyclopentadienyl ligands on the ten carbon atoms. This arrangement was a shocking novelty when first discovered, [25] but the discovery of ferrocene ushered in a whole new branch of organometallic chemistry. Ferrocene itself can be used as the backbone of a ligand, e.g. dppf. Ferrocene itself can be oxidized to the ferrocene cation (Fc+); the ferrocene/ferrocene couple is often used as a reference in electrochemistry.[26] ferrocene

History of wrought iron Very old items made of iron are much rarer than items made of gold or silver, since iron corrodes easily.[27] G.A. Wainwright found 3500 B.C. B.C. Meteoric iron beads. C. or earlier at Gerzah, Egypt.[28] The beads contain 7.5% nickel, indicating a meteoric origin as the iron found in the earth's crust has very little or no nickel content. Highly valued for its celestial origin, meteoritic iron was often used to forge weapons and tools, or entire specimens to be displayed in churches.[28] Elements probably dating from 2500 to 3000 B.C. The Mars symbol made of iron by the Egyptians. Iron had a distinct advantage over that used since ancient times to represent bronze in instruments of war. It was much harder and more durable than bronze even though it was iron. prone to rust. However, this is controversial. Hititologist Trevor Bryce argues that prior to the development of advanced ironworking techniques in India, meteoritic iron weapons used by early Mesopotamian armies had a tendency to break apart in combat due to their high carbon content. ] Iron production first began in the Middle Bronze Age, but it took several centuries for iron to replace bronze. Cast iron specimens.

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196 from Asmar, Mesopotamia and the Tall Chagar Bazaar in northern Syria were found sometime between 2700 and 3000 BC. manufactured.[30] The Hittites seem to have been the first to understand the extraction of iron from their ores and considered it very important to their society. They began between 1500 and 1200 BC. with the smelting of iron. C. and the practice spread to the rest of the Middle East after his empire collapsed in 1180 B.C. Chr. c.[30] The later period is called the Iron Age. Iron smelting, and with it the Iron Age, came to Europe two hundred years later and reached Zimbabwe, Africa in the eighth century.[30] Iron does not appear in China until between 700 and 500 BC. before. C. [31] Iron smelting may have been introduced to China via Central Asia.[32] The oldest evidence of the use of a blast furnace in China dates back to the 1st century AD. C., [] and cupola furnaces have been used since the Warring States period (403-221 BC). The use of the blast furnace and dome remained widespread throughout the Song and Tang dynasties. [ ] The Delhi Iron Pillar is an example of Indian methods of iron mining and iron processing. Delhi's Iron Pillar has withstood corrosion over the past 1,600 years.

Cast iron artifacts are found in India from 1800 to 1200 BC. found. C.,[] and in the Levant from about 1500 BC. C. (indicating a foundry in Anatolia or the Caucasus).[34][35] The book of Genesis, fourth chapter, verse 22 contains the first mention of iron in the Old Testament of the Bible; "Tubal-Cain, master of all craftsmen of bronze and iron".[27] Other verses allude to the mining of iron (Job 28:2), iron as a needle (Job 19:24), and furnaces (Deuteronomy 4:20). ), chariots (Joshua 17:16), nails (1 Chronicles 22:3), saws and axes (2 Sam. 12:31), and cooking implements (Ezekiel 4:3).[36] Metal is also mentioned in the New Testament, for example in Acts chapter 12 verse 10, "[Peter went through] the iron gate that leads into the city" of Antioch.[37] Ironwork was made at the end of the 11th century BC. introduced into Greece. C. [38] The expansion of ironworks in central and western Europe is linked to Celtic expansion. According to Pliny the Elder, the use of iron was common in Roman times.[28] The annual iron production of the Roman Empire is estimated at 84,750 t,[39] while the equally populous Han China produced about 5,000 t.[40] During the Industrial Revolution in Britain, Henry Cort began using innovative production systems to refine pig iron into wrought (or bar) iron. In 1783 he patented the puddle process for refining iron ore. It was later improved by others including Joseph Hall.

Cast iron Cast iron was first used in the 5th century BC. Made in China. C.,[41] but it hardly reached Europe until the Middle Ages.[42][48] The first cast iron artifacts were discovered by archaeologists in what is now Luhe County, Jiangsu, China. Cast iron was used in ancient China for war, agriculture, and architecture. [] Means were found in Europe in the Middle Ages to produce wrought iron from cast iron (known as pig iron in this context) using fine forges. Charcoal was needed as fuel for all these processes.

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197 Medieval blast furnaces were about 3 meters high and made of refractory brick; Forced air was usually provided by hand bellows. Modern blast furnaces have become much larger. In 1709 Abraham Darby I built a coke-fired blast furnace for the production of cast iron. The consistent availability of cheap iron was one of the factors that led to the industrial revolution. In the late 18th century, cast iron began to replace wrought iron for certain purposes because it was cheaper. It was not until the 18th century that the carbon content in iron was mentioned as the reason for the differences in the properties of wrought iron, cast iron and steel.[30]

Coalbrookdale by night, 1801. Blast furnaces illuminate the steel town of Coalbrookdale.

Because iron became cheaper and more common, it also became an important structural material after the first iron bridge was built in 1778.

Steel Steel (having a lower carbon content than pig iron but higher than wrought iron) was first produced in ancient times through the use of a bloomery. Blacksmiths in Luristan in western Iran made around 1000 BC. good steel. c.[30] Around 300 BC Improved versions, Wootz steel from India and Damascus steel from China were then developed. c. and 500 d. C or These methods were specialized so that steel did not become an important commodity until the 1850s.[43] In the 17th century, new methods were developed to make it by cementing iron bars in the cementing process. During the Industrial Revolution, new methods were developed to produce carbon-free iron bars, which were later used to make steel. In the late 1850s, Henry Bessemer invented a new steelmaking process that involved blowing air through molten pig iron to produce mild steel. This made steel much cheaper, resulting in wrought iron not being made.[44]

Foundations of modern chemistry Antoine Lavoisier used the reaction of water vapor with metallic iron in a red-hot iron tube to produce hydrogen in his experiments, which led to the demonstration of mass conservation. The anaerobic oxidation of iron at high temperature can be represented schematically by the following reactions: Fe + H2O → FeO + H2 2 Fe + 3 H2O → Fe2O3 + 3 H2 3 Fe + 4 H2O → Fe3O4 + 4 H2

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Industrial production The production of iron or steel is a process consisting of two main steps, unless the desired product is cast iron. The first stage is the production of pig iron in a blast furnace. Alternatively, it can be reduced directly. The second is to make wrought iron or steel from pig iron through an additional process. For some limited purposes, such as B. the cores of electromagnets, pure iron is produced by electrolysis of a solution of iron sulfate.

Blast Furnace Ninety percent of all metal ore mining is for iron production [citation needed]. Industrially, iron ores, mainly hematite (nominally Fe2O3) and magnetite (Fe3O4), are produced in a carbothermic reaction (carbon reduction) in a blast furnace at temperatures around 2000 °C. In a blast furnace, iron ore, coal in the form of coke, and a flux such as limestone (which is used to remove silica impurities in the ore that would otherwise clog the furnace with solids) are fed into the top of the blast furnace. Oven . Furnace while a massive blast of hot air, about 4 tons per ton of iron, [48] is forced into the furnace at the bottom.

The process of refining molten iron ore to produce wrought iron from pig iron, with the illustration at right showing men working in a blast furnace, from Tiangong Kaiwu Encyclopedia published by Song Yingxing in 1637.

In the blast furnace, coke reacts with compressed air oxygen to form carbon monoxide: 2 C + O2 → 2 CO Carbon monoxide reduces iron ore (hematite in the chemical equation below) to molten iron, thereby converting it to carbon dioxide: Fe2O3 + 3 CO → 2 Fe + 3 CO2 A part of the iron in the lower high-temperature area of the furnace reacts directly with the coke:

How iron was mined in the 19th century

2 Fe2O3 + 3 C → 4 Fe + 3 CO2 fluxes are present to melt impurities in the mineral, mainly silica sand and other silicates. Common fluxes are limestone (mainly calcium carbonate) and dolomite (calcium and magnesium carbonate). Other fluxes can be used depending on the impurities that need to be removed from the mineral. In the heat of the furnace, the limestone breaks down into calcium oxide (also called quicklime): CaCO3 → CaO + CO2 Calcium oxide then combines with silicon dioxide to form a liquid slag. CaO + SiO2 → CaSiO3 The slag melts with the furnace heat. At the bottom of the furnace, the molten slag floats on top of the denser cast iron, and openings are made in the sides of the furnace to allow the iron and slag to escape separately. The cooled iron is called pig iron, while the slag can be used as a material in road construction or to improve mineral-poor soils for agriculture[48].

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Direct Iron Reduction As coke becomes increasingly regulated due to environmental concerns, alternative iron processing methods have been developed. Direct Iron Reduction[48] reduces iron ore to a powder called "spongy" iron or "straight" iron, suitable for steelmaking. There are two main reactions that take place in the direct reduction process: Natural gas is partially oxidized (with heat and a catalyst): 2 CH4 + O2 → 2 CO + 4 H2

This pile of iron ore pellets is used in steel production.

These gases are then treated with iron ore in a furnace, resulting in solid sponge iron: Fe2O3 + CO + 2H2 → 2Fe + CO2 + 2H2O Silica is removed by adding a limestone flux.

Other Processes Pig iron is not pure iron but contains 4-5% dissolved carbon with small amounts of other impurities such as sulphur, magnesium, phosphorus and manganese. Since carbon is the main impurity, iron (pig iron) becomes brittle and hard. Also known as cast iron, this form of iron is used to cast items in foundries such as stoves, pipes, radiators, lamp posts and rails. Alternatively, pig iron can be processed into steel (containing up to 2% carbon) or wrought iron (technically pure iron). Various methods have been used for this, including fine forging, puddle furnaces, Bessemer converters, open furnaces, basic oxygen furnaces and electric arc iron-carbon phase diagram, various stable solid-form furnaces. In all cases, the goal is to oxidize some or all of the carbon along with other impurities. On the other hand, other metals can be added to make steel alloys. The hardness of steel depends on its carbon content: the higher the carbon content, the greater the hardness and the lower the ductility. Steel properties can also be modified by various methods. During annealing, a steel part is heated to 700–800 °C for several hours and then gradually cooled. It makes steel softer and more malleable. Steel can be hardened by cold working. The metal is bent or hammered into its final shape at a relatively low temperature. Cold forging involves punching a piece of steel with a heavy press. Keys are commonly made by cold forging. cold rolling, which consists of making a thinner but harder plate, and cold drawing, what

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200 produces a finer but stronger wire, are two other cold working methods. To harden steel, it is heated over glowing coals and then cooled by immersion in water. It becomes harder and brittle. If it is too hard, it is heated to the required temperature and allowed to cool. The steel thus formed is less brittle. Heat treatment is another way to harden steel. Steel becomes red hot and then cools down quickly. Iron carbide molecules are broken down by heat but don't have time to reform. Because the free carbon atoms are bonded together, the steel becomes much harder and stronger than before.[48] Sometimes both tenacity and tenacity are desired. A process called cementing can be used. The steel is heated to around 900°C and then immersed in oil or water. The carbon in the oil can diffuse into the steel, making the surface very hard. The surface cools quickly, but the interior cools slowly, creating an extremely hard surface and a tough, durable inner layer. Iron can be passivated by immersion in a concentrated nitric acid solution. This forms a protective oxide layer on the metal, protecting it from further corrosion.[45]

Applications Metallurgical iron production 2009 (million tons)[46] Country

Iron ore Pig iron Direct iron

Stahl

porcelain

1.114,9

549,4

573,6

Australia

393,9

4.4

5.2

Brazil

305,0

25.1

Japan

0,011

66,9

26,5 87,5

257,4

38.2

23.4

63,5

Russia

92.1

43,9

4.7

60,0

Ukraine

65,8

25.7

29,9

South Korea 0.1

27.3

48,6

Deutschland

20.1

Welt

0,4 1.594,9

914,0

0,38 64,5

32,7 1.232,4

Iron is the most common of all metals, accounting for 95% of global metal production. [citation needed] Its low cost and high strength make it indispensable for engineering applications such as the construction of machinery and machine tools, large ships, and structural components for buildings. Because pure iron is fairly soft, it is more common to combine it with alloying elements to form steel. Commercially available iron is graded for purity and abundance of additives. Pig iron contains between 3.5 and 4.5% carbon[] and varying amounts of impurities such as sulphur, silicon and phosphorus. Pig iron is not a marketable product but an intermediate step in the production of cast iron and steel. By reducing impurities in pig iron that negatively affect material properties, such as sulfur and phosphorus, cast iron is produced that contains 2-4% carbon, 1-6% silicon and small amounts of manganese. It has a melting point in the 1420-1470K range, lower than either of its two main components, making it the first product to melt when carbon and iron are heated together. Their mechanical properties are very different and depend on the form that the carbon takes in the alloy. "White" cast iron contains its carbon in the form of cementite or iron carbide. This hard, brittle compound dominates the mechanical properties of white cast iron, making it tough but not impact resistant. the broken one

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The 201 surface of a white cast iron is filled with fine facets of broken iron carbide, a very clear, silvery lustrous material, hence the name. In gray iron, the carbon exists as fine discrete graphite flakes and also makes the material brittle because the sharp-edged graphite flakes create stress concentration points within the material. A newer variety of gray iron, known as ductile iron, is specially treated with traces of magnesium to change the shape of the graphite into spheroids or nodules, reducing stress concentrations and greatly increasing the material's toughness and strength. Wrought iron contains less than 0.25% carbon but large amounts of slag that give it a fibrous character.[] It is a hard and malleable product, but not as fusible as pig iron. If you upgrade it to the brim, you'll lose it quickly. Wrought iron is characterized by the presence of fine slag fibers trapped within the metal. Wrought iron is more corrosion resistant than steel. It has been almost completely replaced by mild steel for traditional "wrought iron" and forged products. Mild steel corrodes more easily than wrought iron, but is cheaper and more readily available. Carbon steel contains 2.0% carbon or less[] with small amounts of manganese, sulfur, phosphorus, and silicon. Steel alloys contain varying amounts of carbon and other metals such as chromium, vanadium, molybdenum, nickel, tungsten, etc. Their alloy content adds to their cost, so they are generally only used for specific purposes. However, a common steel alloy is stainless steel. Recent developments in ferrous metallurgy have produced an ever-growing range of micro-alloy steels, also known as "HSLA" or low-alloy high-strength steels, which contain small additions to achieve high strength and often spectacular hardness at minimal cost. In addition to traditional applications, iron is also used to protect against ionizing radiation. Although lighter than another traditional protective material, lead, it is mechanically much more resistant. The diagram shows the radiation attenuation as a function of energy. The main disadvantage of iron and steel is that pure iron and most of its alloys will rust if not protected in some way. Painting, galvanizing, passivating, plastic coating and burnishing serve to protect iron from oxidation by excluding water and oxygen or by cathodic protection against corrosion.

Photon mass attenuation coefficient for iron.

Iron compounds Although their metallurgical role is quantitatively dominant, iron compounds are ubiquitous in industry and are used in many niche applications. Iron catalysts are traditionally used in the Haber–Bosch process to produce ammonia and in the Fischer–Tropsch process to convert carbon monoxide to hydrocarbons for fuel and lubricants.[47] Powdered iron in an acidic solvent was used in the Bechamp reduction, the reduction of nitrobenzene to aniline.[48] Ferric chloride is used in water purification and wastewater treatment, in textile dyeing, as a colorant in paints, as an additive in animal feed, and as a copper corrosion agent in the manufacture of copper plate. printed circuit board.[49]] It can also be dissolved in alcohol to form iron dye. The other halides are typically limited to laboratory applications. Ferrous sulfate is used as a precursor to other iron compounds. It is also used to reduce chromate in cement. It is used to fortify foods and to treat iron deficiency anemia. These are its main uses. Iron(III) sulphate is used to settle the smallest waste water particles in the pool water. Ferrous chloride is used as a reducing flocculant, in the formation of iron complexes and magnetic iron oxides, and as a reducing agent in organic synthesis.

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Biological function Iron is abundant in biology.[50] Iron proteins are found in all living organisms, from evolutionarily primitive archaea to humans. The color of blood is due to hemoglobin, an iron-rich protein. As shown by hemoglobin, iron is often bound to cofactors, e.g. in we have. Iron and sulfur groups are ubiquitous and include nitrogenase, the enzymes responsible for biological nitrogen fixation. Influential evolutionary theories have cited a role for iron sulfides in the global iron-sulfur theory. Iron is a necessary trace element found in almost all living organisms. Iron-containing enzymes and proteins, often with prosthetic heme groups, are involved in many biological oxidations and transports. Examples of proteins in higher organisms are hemoglobin, cytochrome (see high-valent iron), and catalase.[51]

Bioinorganic Compounds The most commonly known and studied "bioinorganic" iron compounds (i.e. iron compounds used in biology) are the hemeproteins: examples are hemoglobin, myoglobin and cytochrome P450. These compounds can transport gases, build enzymes, and be used to transfer electrons. Metalloproteins are a group of proteins with metal ion cofactors. Some examples of iron metalloproteins are ferritin and rubredoxin. Many vital enzymes contain iron, such as catalase, lipoxygenases and IRE-BP.

Structure of heme b, in the protein the additional ligand(s) would be bound to Fe.

Health and Nutrition Iron is ubiquitous, but particularly rich sources of iron include red meat, lentils, beans, poultry, fish, leafy greens, watercress, tofu, chickpeas, black-eyed peas, molasses, fortified breads and fortified breakfast cereals. . Iron is found in small amounts in molasses, teff, and flour. Iron from meat (heme iron) is absorbed more easily than iron from vegetables.[52] Although some studies suggest that heme/hemoglobin in red meat has effects that may increase the likelihood of colon cancer,[][] there is still some controversy,[53] and some studies even suggest that there is not enough Evidence exists to support such claims [54] Iron supplied via dietary supplements is commonly found as ferrous fumarate, although ferrous sulfate is less expensive and is just as well absorbed. Elemental iron or reduced iron, although absorbed with only one-third to two-thirds the efficiency (relative to ferrous sulfate),[55] is commonly added to foods such as breakfast cereals or fortified wheat flour. Iron is more available to the body when chelated into amino acids[] and is also available as a regular iron supplement. Often the amino acid chosen for this purpose is the cheaper and more common amino acid glycine, leading to "ferrous glycinate" supplements. Iron (heme-based iron has higher bioavailability).[56] Infants may need iron supplementation when bottle-fed with cow's milk.[57] Blood donors and pregnant women are at particular risk of low iron levels and are generally advised to supplement their iron intake.[58]

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Absorption and storage Iron uptake poses a problem for aerobic organisms because iron is poorly soluble in the neutral pH range. Therefore, the bacteria developed high-affinity sequestrants, so-called siderophores.[59][60][61] Once ingested, cellular iron storage is carefully regulated; "Free" iron ions do not exist as such. An important component of this regulation is the protein transferrin, which binds iron ions absorbed from the duodenum and transports them to the cells in the blood.[62] In animals, plants, and fungi, iron is often the metal ion incorporated into the heme complex. Heme is an essential component of cytochrome proteins that mediate redox reactions and of oxygen-carrying proteins such as hemoglobin, myoglobin, and leghemoglobin. Inorganic iron contributes to redox reactions on the iron and sulfur groups of many enzymes such as nitrogenase (which is involved in the synthesis of ammonia from nitrogen and hydrogen) and hydrogenase. Non-heme iron proteins include the enzymes methane monooxygenase (oxidizes methane to methanol), ribonucleotide reductase (reduces ribose to deoxyribose; DNA biosynthesis), hemerythrins (oxygen transport and fixation in marine invertebrates), and purpuric phosphatase (hydrolysis of phosphate esters). ). . Iron distribution in mammals is tightly regulated, in part because iron ions have a high potential for biological toxicity.[63]

Regulation of Absorption Iron absorption is tightly regulated by the human body, which has no regulated physiological means of iron elimination. Only small amounts of iron are lost daily due to detachment of skin and mucosal epithelial cells, so iron levels are mainly controlled by regulation of absorption.[64] In some people, the regulation of iron absorption is impaired by a genetic defect that maps to the HLA-H gene region on chromosome 6. In these people, excessive iron intake can lead to iron overload disorders. hemochromatosis. Many people have a genetic susceptibility to iron overload without knowing it or having a family history of the problem. For this reason, it is recommended that people do not take iron supplements unless they are iron deficient and have consulted a doctor. It is estimated that hemochromatosis causes disease in 0.3% to 0.8% of Caucasians.[65] MRI finds that iron accumulates in the hippocampus of the brain of people with Alzheimer's disease and in the substantia nigra of people with Parkinson's disease.[66]

Permeable Reactive Barriers Zero-valent iron is the most important reactive material for permeable reactive barriers.[67]

NFPA 704 Precautions

Fire diamond for powder iron metal

Large amounts of ingested iron can lead to excessive levels of iron in the blood. Elevated levels of free iron(II) in the blood react with peroxides to produce free radicals, which are highly reactive and can damage DNA, proteins, lipids, and other cellular components. Therefore, iron toxicity occurs when free iron is present in the cell, which usually occurs when iron levels exceed transferrin's ability to bind iron. Damage to cells in the gastrointestinal tract can also prevent them from regulating iron absorption, causing blood levels to rise further. Iron usually does harm

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204 in the heart, liver, and other sites, which can lead to significant side effects including coma, metabolic acidosis, shock, liver failure, coagulopathy, adult respiratory distress syndrome, long-term organ damage, and even death. [ ] People perceive iron. Toxicity above 20 milligrams of iron per kilogram of body mass, with 60 milligrams per kilogram considered the lethal dose. toxicological causes of death in children under the age of six.[] The Dietary Reference Intake (DRI) lists the Tolerable Upper Intake Level (UL) for adults as 45 mg/day. For children under 14 years of age, the UL is 40 mg/day. Medical management of iron toxicity is complicated and may involve the use of a specific chelating agent called deferoxamine to bind and eliminate excess iron from the body.[][68]

References [7] G Rugel, T Faestermann, K Knie, G Korschinek, M Poutivtsev, D Schumann, N Kivel, I Günther-Leopold, R Weinreich, M Wohlmuther: New Measurement of 60 half-life. In: Physical Review Letters. 103, 2009, p., [24]. [27] Weeks of 1968, p.29. [28] Weeks of 1968, p. 31. [30] Weeks of 1968, p. 32. [31] Sawyer, Ralph D. and Mei-chun Sawyer. The Seven Military Classics of Ancient China. Rock: Westview, (1993), p. 10. [32] Pigott, Vincent C. (1999). p. 8. [33] Pigott, Vincent C. (1999). Archaeometallurgy of the Asian Old World. Philadelphia: University of Pennsylvania Museum of Archeology and Anthropology. ISBN 0-924171-34-0, p. 191. [36] weeks of 1968, p. 29-30. [37] Weeks from 1968, p. 30. [38] Riederer, Josef; Wartke, Ralf B.: "Iron", Cancik, Hubert; Schneider, Helmuth (ed.): Brill's New Pauly, Brill 2009 [39] Craddock, Paul T. (2008): "Mining and Metallurgy" and: Oleson, John Peter (ed.): The Oxford Handbook of Engineering and Technology in Classical World, Oxford University Press, ISBN 978-0-19-518731-1, p. 108 [40] Wagner, Donald B.: "The State and the Iron Industry in Han China", NIAS Publishing, Copenhagen 2001, ISBN 87-87062-77-1, p. 73 [41] originally published in [42] Giannichedda, Enrico (2007): "Metal Production in Late Antiquity" (http://books.google.com/books?id=LAgxAJNXhFwC& pg=PA200), in Technology in Transition AD 300-650 Lavan, L.; Zanini, E. and Sarantis, A. (eds.), Brill, Leiden; ISBN 90-04-16549-5, p. 200. [43] Spoerl, Joseph S. A Brief History of Iron and Steel Production (http://www.anselm.edu/homepage/dbanach/h-carnegie-steel.htm). Saint Anselm College [46] Steel Statistical Yearbook 2010 (http://www.worldsteel.org/statistics/statistics-archive/yearbook-archive.html). World Steel Association [50] e-book ISBN 978-94-007-5561-1 electronic[52] Food Standards Agency - Eating Well, Staying Well - Iron Deficiency (http://www.eatwell.gov.uk/healthissues/ iron deficiency / ). Eatwell.gov.uk (2012-03-05). Accessed on 06/27/2012.

Bibliography • Weeks, María Elvira; Totenter, Henry M. (1968). "Elements Known to the Ancients". discovery of the elements. Easton, PA: Journal of Chemical Education. pp. 29-40. ISBN0-7661-3872-0. LCCN 68-15217 (http://lccn.loc.gov/68-15217).

Leitura Adicional • H.R. Schubert, History of the British Iron and Steel Industry...to AD 1775 (Routledge, Londres, 1957) • R.F. Tylecote, History of Metallurgy (Instituto de Materiais, Londres 1992). • R F Tylecote, “Iron in the Industrial Revolution” in J Day and R F Tylecote, The Industrial Revolution in Metals (Materials Institute 1991), 200–60.

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Externe Links • Elemental: Iron (http://education.jlab.org/itselemental/ele026.html) • The Most Tightly Bound Nuclei (http://hyperphysics.phy-astr.gsu.edu/hbase/nucene/nucbin2 . html) • Chemistry in Your Element Podcast (http://www.rsc.org/chemistryworld/podcast/element.asp) (MP3) von Chemistry World der Royal Society of Chemistry: Iron (http://www.rsc.org / images/ CIIE_iron_48kbps_tcm18-120046.mp3) • Eisen (http://www.periodicvideos.com/videos/026.htm) im Periodensystem der Videos (University of Nottingham) • Metallurgie für Nichtmetallarbeiter (http:// books.google .com/books?id=brpx-LtdCLYC&pg=frontcover&d#v=onepage&q&f=true)

Redox Redox reactions (reduction-oxidation) encompass all chemical reactions in which atoms change their oxidation state, ie redox reactions involve the transfer of electrons between species. It can be as simple as the oxidation of carbon to produce carbon dioxide (CO2) or the reduction of carbon by hydrogen to produce methane (CH4), or it can be as complex as the oxidation of glucose (C6H12O6) in humans body through a series of complex electron transfer processes.

Sodium and fluorine combine ionically to form sodium fluoride. Sodium loses its outer electron to give it a stable electronic configuration, and that electron enters the fluorine atom exothermically. Ions with opposite charges attract each other. Sodium is oxidized and fluorine is reduced.

The term “redox” comes from two concepts related to electron transfer: reduction and oxidation.[1] It's easy to explain: • Oxidation is the loss of electrons, or an increase in the oxidation state of a molecule, atom, or ion. • Reduction is the acquisition of electrons or a reduction in the oxidation state of a molecule, atom, or ion.

The two parts of a redox reaction.

Although oxidation reactions usually involve the formation of oxides from oxygen molecules, these are just specific examples of a more general concept of reactions involving electron transfer. Redox reactions, or oxidation-reduction reactions, have several similarities to acid-base reactions. Like acid-base reactions, redox reactions are a combined set, meaning there cannot be an oxidation reaction without a reduction reaction occurring at the same time. Oxidation alone and reduction alone are called half-reactions because any two half-reactions together form a complete reaction. When writing half-reactions, electrons gained or lost are usually explicitly included so that the half-reaction is balanced in terms of electric charge.

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While these descriptions are sufficient for many purposes, they are not exactly accurate. Oxidation and reduction correctly refer to a change in oxidation state: the actual transfer of electrons may never occur. Therefore, oxidation is best defined as an increase in oxidation state and reduction as a decrease in oxidation state. In practice, electron transfer always results in a change in oxidation state, but there are many reactions that are classified as "redox" even though no electron transfer occurs (e.g. those involving covalent bonds).

Etymology "Redox" is a made-up word from "oxidation" "reduction", better known as oxidation-reduction.

It's like

The word oxidation originally implied a reaction with oxygen to form an oxide, since (di)oxygen was historically the first recognized oxidizing agent. The term was later extended to include oxygen-like substances that perform parallel chemical reactions. Eventually the meaning was generalized to include all processes in which electrons are lost. The word reduction originally referred to weight loss by heating a metallic ore, such as a metal oxide, to extract the metal. In other words, the ore has been "reduced" to metal. Antoine Lavoisier (1743-1794) showed that this weight loss was due to the loss of oxygen in gaseous form. Later, scientists realized that the metal atom gains electrons in this process. The meaning of reduction was later generalized to include all processes involving electron acquisition. Although "reduction" seems contradictory when it comes to gaining electrons, it can be helpful to think of reduction in terms of oxygen loss, which had its historical significance.

rusty iron

A campfire. Combustion consists of redox reactions involving electronization and deelectronization to describe the reduction and oxidation processes, respectively, as they occur at the electrodes. These words are analogous to protonation and deprotonation, but they have not been widely used by chemists.

The term “hydrogenation” could also be used instead of reduction, since hydrogen is the reducing agent in a large number of reactions, especially in organic chemistry and biochemistry. But unlike oxidation, which has been generalized beyond its root element, hydrogenation retained its specific connection to reactions that add hydrogen to another substance (e.g., the hydrogenation of unsaturated fats to saturated fats, R-CH=CH- R + H2 → R -CH2 -CH2 -R).

Redox

Oxidizing and reducing agents In redox processes, the reducing agent transfers electrons to the oxidizing agent. Thus, in the reaction, the reducing or reducing agent loses electrons and is oxidized, and the oxidizing or oxidizing agent gains electrons and is reduced. The oxidizing and reducing agent pair involved in a particular reaction is called a redox couple. A redox couple is a reducing species and its corresponding oxidized form, e.g. B. Fe2+/Fe3+.

Oxidants Substances that have the ability to oxidize other substances (make them donate electrons) are called oxidants or oxidants and are known as oxidants, oxidants, or oxidants. That is, the oxidizing agent (oxidizing agent) withdraws electrons from another substance, thereby reducing. And because it “picks up” electrons, the oxidizing agent is also known as an electron acceptor. Hence the name, oxygen is the ultimate oxidizing agent. Oxidizing agents are typically chemicals with elements in high oxidation states (e.g. H 2 O 2 , MnO− 4, CrO 3, Cr 2O2− 7, OsO 4) or strongly electronegative elements (O, F, Cl, Br) that have electrons can absorb oxidation of another substance 2 2 2 2.

Reducing substances that have the ability to reduce other substances (make them gain electrons) are considered reducing agents or reducing agents and are known as reducing agents, reducing agents, or reducing agents. The reducing agent (reducing agent) transfers electrons to another substance, thereby being oxidized. And because it "donates" electrons, the reducing agent is also known as an electron donor. Electron donors can also form charge-transfer complexes with electron acceptors. Reducing agents in chemistry are very diverse. Electropositive elemental metals such as lithium, sodium, magnesium, iron, zinc and aluminum are good reducing agents. These metals donate or donate electrons easily. Hydride transfer agents such as NaBH4 and LiAlH4 are used extensively in organic chemistry,[3][4] mainly in the reduction of carbonyl compounds to alcohols. Another reduction method involves the use of hydrogen (H2) gas with a palladium, platinum, or nickel catalyst. These catalytic reductions are mainly used in the reduction of carbon-carbon double or triple bonds.

Standard Electrode Potentials (Reduction Potentials) Each half-reaction has a standard electrode potential (E0cell) which, under standard conditions, is equal to the equilibrium potential (or voltage) difference (E0cell) of an electrochemical cell in which the reaction is considered a half-reaction, and the cathode the anode is a standard hydrogen electrode where hydrogen is oxidized: ½ H2 → H+ + e-. The electrode potential of each half-reaction is also known as the reduction potential E0red or potential when the half-reaction occurs at a cathode. The reduction potential is a measure of the tendency of the oxidizing agent to reduce. Its value is by definition zero for H+ + and − → ½ H2, positive for oxidants stronger than H+ (e.g. +2.866 V for F2) and negative for oxidants weaker than H+ (e.g. -0.763V for Zn2+). . [5] For a redox reaction occurring in a cell, the potential difference E0cell = E0cathode – E0anode Historically, however, the reaction potential at the anode was sometimes expressed in terms of oxidation potential, E0ox = –E0 . The oxidation potential is a measure of the reducing agent's tendency to oxidize, but it is not

207

Redox

208

represent the physical potential at an electrode. With this notation, the cell voltage equation is written with a plus sign E0cell = E0cathode + E0ox (anode)

Examples of redox reactions A good example is the reaction between hydrogen and fluorine, in which hydrogen is oxidized and fluorine is reduced: H 2+ F 2 → 2 HF We can write this general reaction as two half-reactions:

Illustration of a redox reaction

the oxidation reaction: H + − 2 → 2H + 2e and the reduction reaction: F 2

+ 2e− → 2F−

The isolated analysis of each half-reaction can often provide information about the entire chemical process. Since there is no net change in charge during a redox reaction, the number of excess electrons in the oxidation reaction must equal the number consumed by the reduction reaction (as shown above). Even in molecular form, elements always have an oxidation state of zero. In the first half of the reaction, hydrogen is oxidized from a zero oxidation state to a +1 oxidation state. In the second half of the reaction, fluorine is reduced from a zero oxidation state to a −1 oxidation state. The addition of the reactions annihilates the electrons: H → 2 H+ + 2 e− 2

F → 2 F− − 2+2e H → 2 H+ + 2 F− 2+F 2

And the ions combine to form hydrogen fluoride: 2 H+ + 2 F− → 2 HF The general reaction is: H 2+ F 2 → 2 HF

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209

Metal displacement In this type of reaction, a metal atom in a compound (or in a solution) is replaced by an atom of another metal. For example, copper is precipitated when metallic zinc is placed in a copper(II) sulfate solution: Zn(s)+ CuSO4(aq) → ZnSO4(aq) + Cu(s) In the above reaction, zinc O displaces metal copper(II) from the copper sulphate solution, thereby releasing free metallic copper. The ionic equation for this reaction is: Zn + Cu2+ → Zn2+ + Cu

A redox reaction is the force behind an electrochemical cell such as the galvanic cell pictured. The battery consists of a zinc electrode in a ZnSO4 solution connected to a copper electrode in a CuSO4 solution via a wire and a porous disc.

As two half-reactions we see that zinc is oxidized: Zn → Zn2+ + 2 e− and copper is reduced: Cu2+ + 2 e− → Cu

Further examples • The oxidation of iron(II) to iron(III) by hydrogen peroxide in the presence of an acid: Fe2+ → Fe3+ + e− H2O2 + 2 e− → 2 OH− General equation: 2 Fe2+ + H2O2 + 2 H+ → 2 Fe3+ + 2 H2O • The reduction of nitrate to nitrogen in the presence of an acid (denitrification): 2 NO3− + 10 e− + 12 H+ → N2 + 6 H2O • The combustion of hydrocarbons as in an internal combustion engine containing water, carbon dioxide, some partially produces oxidized forms such as carbon monoxide and thermal energy. Complete oxidation of carbonaceous materials produces carbon dioxide. • In organic chemistry, the gradual oxidation of a hydrocarbon with oxygen produces water and, in turn, an alcohol, an aldehyde or ketone, a carboxylic acid, and finally a peroxide. Rusty iron on pyrite cubes

Redox Reactions in Industry The main process of reducing ore at high temperatures to produce metals is known as smelting. Oxidation is used in a variety of industries, e.g. B. in the manufacture of cleaning products and the oxidation of ammonia to produce nitric acid, which is used in most fertilizers. Redox reactions are the basis of electrochemical cells.

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The electroplating process uses redox reactions to coat objects with a thin layer of material, such as B. chrome-plated car parts, gold-plated silverware and jewelry. The manufacture of compact discs depends on a redox reaction that coats the disc with a thin layer of metallic film.Wikipedia:Clarify

Redox reactions in biology.

Above: ascorbic acid (reduced form of vitamin C) Below: dehydroascorbic acid (oxidized form of vitamin C)

Many important biological processes involve redox reactions. For example, cellular respiration is the oxidation of glucose (C6H12O6) to CO2 and the reduction of oxygen to water. The summary equation for cellular respiration is: C6H12O6 + 6 O2 → 6 CO2 + 6 H2O The process of cellular respiration is also heavily dependent on the reduction of NAD+ to NADH and the reverse reaction (the oxidation of NADH to NAD+). Photosynthesis and cellular respiration complement each other, but photosynthesis is not the opposite of the redox reaction in cellular respiration: 6 CO2 + 6 H2O + light energy → C6H12O6 + 6 O2 Biological energy is often stored and released through redox reactions. Photosynthesis involves the reduction of carbon dioxide to sugars and the oxidation of water to molecular oxygen. The reverse reaction, respiration, oxidizes the sugar into carbon dioxide and water. As intermediate steps, reduced carbon bonds are used to reduce nicotinamide adenine dinucleotide (NAD+), which then contributes to the formation of a proton gradient that drives the synthesis of adenosine triphosphate (ATP) and is maintained by the reduction of oxygen. In animal cells, mitochondria perform similar functions. See the article membrane potential. Free radical reactions are redox reactions that occur as part of the homeostasis and elimination of microorganisms, in which an electron is separated from a molecule and then reconnected almost immediately. Free radicals are part of redox molecules and can become harmful to the human body if they are not bound back to the redox molecule or an antioxidant. Unsaturated free radicals can stimulate mutation in the cells they encounter and are therefore causes of cancer. The term redox state is often used to describe the balance of NAD+/NADH and NADP+/NADPH in a biological system such as a cell or an organ. The redox state is reflected in the balance of different sets of metabolites (e.g. lactate and pyruvate, beta-hydroxybutyrate and acetoacetate), the interconversion of which depends on these ratios. An abnormal redox state can develop in a variety of harmful situations, such as hypoxia, shock, and sepsis. The redox mechanism also controls some cellular processes. According to the CoRR hypothesis, redox proteins and their genes must be colocalized for DNA function in mitochondria and chloroplasts for redox regulation.

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211

Redox Cycle A large number of aromatic compounds are enzymatically reduced to free radicals, which contain one more electron than their parent compounds. In general, the electron donor is one of a wide variety of flavoenzymes and their coenzymes. Once formed, these anionic free radicals reduce molecular oxygen to superoxide and regenerate the original compound unaltered. The net reaction is the oxidation of the flavoenzyme coenzymes and the reduction of molecular oxygen to form superoxide. This catalytic behavior has been described as a useless cycle or redox cycle. Examples of molecules that induce the redox cycle are the herbicide paraquat and other vilogens and quinones such as menadione.[6]

Redox Reactions in Geology In geology, redox is important in mineral formation, mineral mobilization, and in some depositional environments. In general, the redox state of most rocks can be identified by the color of the rock. Red is associated with oxidizing formation conditions, and green is typically associated with reducing conditions. White can also be associated with reducing conditions. Famous examples of redox conditions affecting geological processes are uranium deposits and Moqui marble.

Equilibrium of Redox Reactions The description of the general electrochemical reaction of a redox process requires the equilibrium of the oxidation and reduction half-reactions of components. In general, for reactions in aqueous solutions, this involves the addition of H+, OH-, H2O, and electrons to compensate for changes in oxidation.

Acidic medium In acidic medium, H+ ions and water are added halfway through the reactions to balance the overall reaction. For example, when manganese(II) reacts with sodium bismuthate: Unbalanced reaction: Mn2+ (aq) + NaBiO 3(s) → Bi3+ (aq) + MnO − 4 (aq) oxidation:

4H 2O(l) + Mn2+ (aq) → MnO− 4(aq) + 8 H+ (aq) + 5 e−

A uranium mine near Moab, Utah. Note the alternation of red and white/green sandstone. This corresponds to oxidized and reduced conditions in groundwater redox chemistry. The rock forms under oxidizing conditions and is then "bleached" to a white/green state when a reducing fluid flows through the rock. Reduced fluid can also transport uranium-bearing ores.

Redox

212 Reduction:

2 e− + 6 H+ + BiO− 3(s) → Bi3+ (aq) + 3 H 2O(l)

The reaction is balanced by scaling the two half-cell reactions to involve the same number of electrons (multiplying the oxidation reaction by the number of electrons in the reduction step and vice versa): 8H 2O(l) + 2 Mn2+ (aq) → 2 MnO − 4(aq) + 16 H+ (aq) + 10 e− 10 e− + 30 H+ + 5 BiO− 3(s) → 5 Bi3+ (aq) + 15 H 2O(l) The sum of these two reactions eliminates the electron terms and produces the balanced reaction: 14 H+ (aq) + 2 Mn2+ (aq) + 5 NaBiO 3(s) → 7 H 2O(l) + 2 MnO− 4(aq) + 5 Bi3+ (aq) + 5Na+ (aqueous)

Basic medium In basic medium, OH and water ions are added halfway through the reactions to balance the overall reaction. For example, in the reaction between potassium permanganate and sodium sulfite: imbalance reaction: KMnO 4 + Na 2SO 3 + H 2O → MnO 2 + Na 2SO 4 + KOH reduction:

3 e− + 2 H 2O + MnO − 4 → MnO − 2 + 4 OH

Redox

213 Oxidation:

2 OH− + SO 2− 3 → SO 2− 4 + H 2 O + 2 e−

Balancing the number of electrons in the two half-cell reactions gives: 6 e− + 4 H 2O + 2 MnO − 4 → 2 MnO − 2 + 8 OH 6 OH− + 3 SO 2− 3 → 3 SO 2− 4 + 3H 2O + 6 e− The sum of these two half-cell reactions gives the balanced equation: 2 KMnO 4 + 3 Na 2SO 3+ H 2O → 2 MnO 2 + 3 Na 2SO 4 + 2 KOH

Memory Aids The most important redox terms are often confusing for students. [][] For example, an element that is oxidized loses electrons; however, this element is referred to as a reducing agent. Likewise, a reduced element gains electrons and is called an oxidizing agent.[] Acronyms or mnemonics are often used[] to remember what is happening: • “Oil”: oxidation is electron loss, reduction is electron gain.[][ ][][] • "LEO the lion says GER": Electron loss is oxidation, electron acceptance is reduction.[][][][] • "LEORA says GEROA": Electron loss is oxidation (reducing agent) and the acceptance of electrons is reduced (Oxidant).[]

References [5] Potential values of the electrode from

• Schuering, J., Schulz, H.D., Fischer, W.R., Böttcher, J., Duijnisveld, WH. (eds.) (1999). Redox: Fundamentals, Processes and Applications, Springer-Verlag, Heidelberg, 246 pp. ISBN 978-3-540-66528-1 (pdf 3.6 MB) (http://hdl.handle.net/10013/epic.31694 .d001 ) • Tratnyek, Paul G.; Grundl, Timothy J.; Haderlein, Stefan B., eds. (2011). Quimica redox aquática. ACS 1071 Symposium Series. doi: 10.1021/bk-2011-1071 (http://dx.doi.org/10.1021/bk-2011-1071). ISBN9780841226524.

Redox

External links • Chemical Equation Balancer (http://www.berkeleychurchill.com/software/chembal.php): An open source chemical equation balancer that handles redox reactions. • Video – Synthesis of Copper(II) Acetate (http://www.youtube.com/watch?v=rF1ls-v7puQ) February 20, 2009 • Calculator for Redox Reactions (http://www.shodor.org /UNCchem/ advanced/redox/redoxcalc.html) • Redox reactions in Chemguide (http://www.chemguide.co.uk/inorganic/redox/definitions.html#top) • Online balancing of redox reaction equations, balance the equations of each half cell and complete Reactions (http://www.webqc.org/balance.php)

214

Aluminium

215

Aluminium Aluminium Al 13

Magnesium ← Aluminium → SiliziumB ↑

Al ↓ Ga Aluminum on the periodic table Silver-grey metallic appearance

Aluminum Spectral Lines General Properties Name, Symbol, Number

Aluminium, Aluminium, 13

pronunciation

United Kingdom i/ˌæljʉˈmɪniəm/ AL-ew-MIN-ee-am; AND IS. UU. a-LEW-my-name

item category

Metal weapons

group, period, block

13, 3, p.

standard atomic weight

26.9815386(13)

/əˈljuːmɨnəm/

Aluminium

216 Electronic configuration

[Ne] 3s2 3p1 2, 8, 3

history [1]

forecast

Antonio Lavoisier

first isolation

Friedrich Woehler

named after

Humphry Davy

[1]

(1787)

(1827)

(1807)

Phase of physical properties

fest

Density (near room temperature)

2,70 g·cm−3

Density of the liquid in m.p.

2,375 g·cm−3

fusion point

933,47 K, 660,32 °C, 1220,58 °F

boiling point

2792K, 2519°C, 4566°F

heat of fusion

10.71 kJ·mol-1

heat of vaporization

294.0 kJ·mol-1

molar heat capacity

24,200 J mol-1 K-1 vapor pressure

P (Pa)

100

1 k

10 thousand 100 thousand

at T (K) 1482 1632 1817 2054 2364 2790 Atomic properties [2]

[3]

oxidation states

3, 2, 1 (amphoteres Oxid)

electronegativity

1.61 (Pauling Scale)

Ionization energies (more)

1st: 577.5 kJ mol-1 2nd: 1816.7 kJ mol-1 3rd: 2744.8 kJ mol-1

Atomic func

143 hours

covalent ray

121±16h

Aluminium

217 Radio Van der Waals

184h Miscellaneous

crystal structure

face-centered cubic

magnetic request

paramagnetic

Electrical resistance

(20 °C) 28,2 nΩ·m

thermal conductivity

237W·m−1·K−1

thermal expansion

(25 °C) 23,1 µm·m−1·K−1

Speed of Sound (thin bar)

(r.) (rolled) 5,000m s−1

modulus of elasticity

70 GPa

Schneidmodul

26 GPa

Volumenmodul

76 GPa

poison ratio

0,35

Mohs hardness

2,75

Dureza Vickers

167 MPa

Brinell hardness

245 MPa

CAS registration number

7429-90-5

[4]

More stable isotopes Main article: Aluminum isotopes iso

THE

half-life

For the dash 7.17×105y

Al 100%

DM OF (MeV)

1.17

1.8086

magnsio magnsio -

Al is stable with 14 neutrons.

Aluminum (or aluminium) is a chemical element of the boron group with the symbol Al and atomic number 13. It is a soft, ductile, silvery-white metal. Aluminum is the third most abundant element (after oxygen and silicon) and the most abundant metal in the earth's crust. It makes up about 8% by weight of the solid surface of the earth. Metallic aluminum is so chemically reactive that native specimens are rare and restricted to extremely reducing environments. Instead, it is found combined in over 270 different minerals.[5] The most important aluminum ore is bauxite. Aluminum is characterized by its low metal density and its resistance to corrosion due to the phenomenon of passivation. Structural components made from aluminum and its alloys are vital to the aerospace industry and play important roles in other areas of transportation and structural materials. The most useful aluminum compounds, at least by weight, are the oxides and sulfates. Despite their widespread presence in the environment, aluminum salts are not used by any life form. Due to its ubiquity, plants and animals tolerate aluminum well.[6] Because of their prevalence, the potentially beneficial (or otherwise) biological roles of aluminum compounds remain of interest.

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218

Physical Properties

Engraved surface of high purity (99.9998%) aluminum ingot, size 55×37 mm

Aluminum is a relatively soft, durable, lightweight, ductile, and malleable metal with an appearance ranging from silver to dull gray depending on surface roughness. It is non-magnetic and does not light up easily. A cold aluminum film serves as a good reflector (about 92%) of visible light and an excellent reflector (up to 98%) of mid- and far-infrared radiation. The yield strength of pure aluminum is 7 to 11 MPa, while aluminum alloys have a yield strength of 200 MPa to 600 MPa.[7] Aluminum is about a third of the density and rigidity of steel. It's easy to edit, pour,

stretched and extruded. The aluminum atoms are arranged in a face-centered cubic (FCC) structure. Aluminum has a stacking fault energy of about 200 mJ/m2.[8] Aluminum is a good thermal and electrical conductor, it has 59% of copper's conductivity, both thermally and electrically, while only 30% of copper's density. Aluminum can be a superconductor, with a superconducting critical temperature of 1.2 Kelvin and a critical magnetic field of about 100 gauss (10 millitesla).[9]

Resistance to chemical corrosion can be excellent due to a thin surface layer of aluminum oxide that forms when the metal is exposed to air, effectively preventing further oxidation. Stronger aluminum alloys are less resistant to corrosion due to galvanic reactions with bound copper.[7] This corrosion resistance is also often greatly reduced by aqueous salts, particularly in the presence of dissimilar metals. Because of its resistance to corrosion, aluminum is one of the few metals that retains the reflectivity of silver in fine powder form, making it an important ingredient in silver paints. Highly polished aluminum has the highest reflectivity of any metal in the 200-400 nm (UV) and 3000-10,000 nm (far infrared) ranges; in the visible range from 400 to 700 nm it is easily outperformed by tin and silver, and in the range from 700 to 3000 (near IR) by silver, gold, and copper.[10] Aluminum is oxidized with water to hydrogen and heat: 2 Al + 3 H2O → Al2O3 + 3 H2 This conversion is interesting for the production of hydrogen. Challenges include bypassing the formed oxide layer that inhibits the reaction and the associated cost of energy storage through Al-metal regeneration.[11]

Isotopes Aluminum has many known isotopes with mass numbers from 21 to 42; naturally only 27Al (stable isotope) and 26Al (radioactive isotope, t1/2= 7.2×105 y) occur. 27Al has a natural abundance greater than 99.9%. 26Al is produced from argon in the atmosphere by spallation caused by cosmic ray protons. Aluminum isotopes have found practical uses in dating marine sediments, manganese nodules, glacial ice, quartz in rock outcrops, and meteorites. The 26Al to 10Be ratio was used to study the role of sediment transport, deposition, storage, embedment time, and erosion on timescales of 105 to 106 years.[12] Cosmogenes 26Al was first used in studies of the moon and meteorites. Meteor fragments, after leaving their original bodies, are subjected to intense cosmic ray bombardment during their journey through space, resulting in significant production of 26Al. after a fall

Aluminum to Earth, atmospheric shielding drastically reduces the production of 26Al, and its decay can be used to determine the terrestrial age of the meteorite. Meteorite research has also shown that 26Al was relatively abundant at the time our planetary system formed. Most meteorite scientists believe that the energy released by the decay of 26Al was responsible for the melting and differentiation of some asteroids after their formation 4.55 billion years ago.[13]

Naturally occurring stable aluminum is formed when hydrogen fuses with magnesium in large stars or in supernovae.[14] In the Earth's crust, aluminum is the most common metallic element (8.3% by weight) and the third most common of all elements (after oxygen and silicon).[] Due to its strong affinity for oxygen, it is almost never found in the element; instead it is found in oxides or silicates. Feldspars, the most common group of minerals in the earth's crust, are aluminosilicates. Native aluminum metal can only be found as a minor phase in environments with low oxygen volatility, such as B. inside certain volcanoes.[15] Native aluminum has been reported in cold leachate on the northeastern continental slope of the South China Sea, and Chen et al. (2011)[] proposed a theory of its origin as the result of bacterial reduction of tetrahydroxoaluminate Al(OH)4- to metallic aluminum.[] It is also found in the minerals beryl, cryolite, garnet, spinel, and turquoise. Impurities in Al2O3, such as chromium or iron, produce ruby and sapphire gemstones, respectively. Although aluminum is an extremely common and widespread element, common aluminum ores are not cheap sources of the metal. Almost all metallic aluminum is produced from bauxite ore (AlOx(OH)3–2x). Bauxite occurs as a product of weathering of iron-poor and siliceous bedrock under tropical climate conditions.[16] Large deposits of bauxite are located in Australia, Brazil, Guinea and Jamaica, and the main mining areas of the mineral are in Australia, Brazil, China, India, Guinea, Indonesia, Jamaica, Russia and Suriname.

Manufacturing and processing Aluminum forms strong chemical bonds with oxygen. Compared to most other metals, aluminum's high reactivity and the high melting point of most of its ores make it difficult to extract from ores such as bauxite. For example, direct reduction with coal, which is used to make iron, is chemically impossible because aluminum is a stronger reducing agent than coal. Indirect carbothermal reduction can be performed using carbon and Al2O3, forming an Al4C3 intermediate that can produce metallic aluminum at a temperature of 1900-2000 °C. This process is still under development; Bauxite, an important aluminum ore. The rusty red color requires less energy and generates less CO2 than the Hall-Hérout color due to the presence of iron minerals. Process, the most important industrial process for aluminum production.[17] The electrolytic smelting of alumina was originally expensive, in part due to the high melting point of alumina or alumina (about 2,000 °C (3,600 °F)). However, many minerals will dissolve in a second mineral that is already molten, even if the melting temperature is significantly lower than the melting point of the first mineral. Molten cryolite has been found to dissolve alumina at temperatures well below the melting point of pure alumina without interfering with the casting process. In the Hall-Héroult process, alumina is first dissolved in molten cryolite with calcium fluoride and then electrolytically reduced to aluminum at a temperature between 950 and 980 °C (1740 to 1800 °F). Cryolite is a chemical compound of aluminum and sodium fluoride: (Na3AlF6). Although cryolite is found as a mineral in Greenland, its synthetic form is used in industry. Alumina itself is obtained by refining bauxite using the Bayer process.

219

Aluminium

220

The electrolytic process replaced the Wöhler process, in which anhydrous aluminum chloride was reduced with potassium. Both electrodes used in alumina electrolysis are made of carbon. Once refined alumina dissolves in the electrolyte, it dissociates and its ions are free to move. The reaction at the cathode is: Al3+ + 3 e− → Al Here the aluminum ion is reduced. The aluminum metal is then sunk and mined, and usually cast into large blocks called aluminum billets for further processing. Oxygen is produced at the anode: 2 O2− → O2 + 4 e− The carbon in the anode is partially consumed by the subsequent reaction with oxygen to form carbon dioxide. Therefore, the anodes of a reduction cell have to be replaced regularly as they are consumed in the process. Cathodes erode primarily due to electrochemical processes and metal movement. After five to ten years, depending on the current used in electrolysis, a cell has to be rebuilt due to cathode wear. Aluminum electrolysis using the Hall-Héroult process is very energy-intensive, but alternative processes have always proven to be less economical and/or ecological. The world average specific energy consumption is about 15 ± 0.5 kilowatt hours per kilogram of aluminum produced (52 to 56 MJ/kg). Most modern huts achieve around 12.8 kWh/kg (46.1 MJ/kg). (Compare this with the heat of reaction of 31 MJ/kg and the Gibbs free energy of reaction of 29 MJ/kg.) Reduction line currents for older technologies are typically 100 to 200 kiloamps; modern foundries work with about 350 kA. Assays using 500 kA cells have been reported [cit

World trends in aluminum production.

necessary]

The Hall-Heroult process produces aluminum with a purity of more than 99%. Additional purification can be done by the Hoope process. The process involves the electrolysis of molten aluminum with sodium, barium and aluminum fluoride electrolytes. The resulting aluminum is 99.99% pure.[18][19] Depending on the location of the smelter, electrical energy accounts for around 20% to 40% of aluminum production costs. Aluminum production consumes approximately 5% of the electricity generated in the US[20]. Shacks tend to be located where electricity is plentiful and cheap, as in the United Arab Emirates with an oversupply of natural gas and Iceland and Norway with energy from renewable sources. The largest alumina smelters in the world are the People's Republic of China, Russia, Quebec and British Columbia in Canada.[20][21][22] In 2005, the People's Republic of China was the top aluminum producer with nearly a fifth of the world's share, followed by Russia, Canada and the United States, reports the British Geological Survey. Over the past 50 years, Australia has become a major producer of bauxite ore and a major producer and exporter of alumina (before being overtaken by China in 2007).[21][23] Australia produced 68 million tonnes of bauxite in 2010. Australian deposits have some refining problems, some are silica rich but have the advantage of being shallow and relatively easy to mine.[24]

Aluminum spot price 1987 2012

Aluminium

221

Recycling Aluminum is theoretically 100% recyclable without losing its natural properties. According to the International Resource Panel's Metal Stocks in Society report, the global per capita stock of aluminum used in society (ie in cars, buildings, electronics, etc.) is 80 kg. Much of this is more likely to occur in more developed countries (350-500 kg per capita) than in less developed countries (35 kg per capita). For recycling planning, it is important to know the per capita stock and its approximate useful life. Metal recovery through recycling has become an important application in the aluminum industry. Recycling was a quiet activity until the late 1960s, when the increasing use of aluminum beverage cans brought it to the fore.

Aluminium-Recycling-Code

Recycling involves smelting scrap, a process that uses only 5% of the energy used to produce aluminum from ore, although a significant portion (up to 15% of the input) is lost in the form of slag (an iron-like oxide). ash).[25] The slag can be further processed to obtain the aluminum. In Europe, aluminum has high recycling rates, ranging from 42% for beverage cans to 85% for building materials and 95% for transport vehicles.[26] Recycled aluminum is known as secondary aluminum but retains the same physical properties as primary aluminum. Manufactured in a variety of forms, secondary aluminum is used in 80% of alloy injection molding. Another important use is extrusion. White slag from primary aluminum production and secondary recycling still contains reasonable amounts of industrially recoverable aluminum.[27] The process produces aluminum billets along with a very complex waste material. This waste is difficult to manage. Reacts with water to liberate a gas mixture (including but not limited to hydrogen, acetylene, and ammonia) that spontaneously ignites on contact with air;[28] Exposure to moist air results in the release of large amounts of ammonia gas. Despite these difficulties, the waste has found use as a filler in asphalt and concrete.[29]

Compounds in the +3 Oxidation State The vast majority of compounds, including all Al-bearing minerals and all commercially important aluminum compounds, contain aluminum in the 3+ oxidation state. The coordination number of such compounds varies, but Al3+ generally has six or four coordinates. Almost all aluminum(III) compounds are colorless. [ ] Halides All four trihalides are well known. In contrast to the structures of the three heaviest trihalides, aluminum fluoride (AlF3) has six-coordinate Al. The octahedral coordination environment for AlF3 is related to the compactness of the fluoride ion, six of which can fit around the small Al3+ center. AlF3 sublimes (with cracks) at 1291 °C (2356 °F). The coordination numbers are lower for heavier halides. The other trihalides are dimeric or polymeric with tetrahedral Al centers. These materials are made by treating aluminum metal with halogen, although other methods exist. Acidification of oxides or hydroxides produces hydrates. In aqueous solution, halides often form mixtures, often containing hexacoordinate Al centers that are halide and aquo ligands. When aluminum and fluorine are present together in an aqueous solution, they easily form complex ions such as [AlF(H 2 O) 5]2+

Aluminium

222

, AlF 3(H 2O) 3 and [AlF 6]3− . With chloride, polyaluminum agglomerates such as [Al13O4(OH)24(H2O)12]7+ form. Oxides and Hydroxides Aluminum forms a stable oxide known by its mineral name, corundum. Sapphire and ruby are impure corundums contaminated with traces of other metals. The two oxide hydroxides AlO(OH) are boehmite and diaspore. There are three trihydroxides: bayerite, gibbsite and nordstrandite, which differ in their crystal structure (polymorphs). Most are made from ores through a variety of wet processes using acids and bases. Heating the hydroxides leads to the formation of corundum. These materials are central to aluminum production and extremely useful. Carbide, Nitride and Related Materials Aluminum Carbide (Al4C3) is made by heating a mixture of the elements to over 1000°C (1832°F). The light yellow crystals consist of tetrahedral aluminum centers. It reacts with water or diluted acids to form methane. Acetylide, Al2(C2)3, is produced by passing acetylene over heated aluminum. Aluminum nitride (AlN) is the only known nitride for aluminum. Unlike oxides, it has tetrahedral Al centers. Can be made from elements at 800 °C (1472 °F). It's an air-stable material with a usefully high thermal conductivity. Aluminum phosphide (AlP) is similarly produced and hydrolyzed to phosphine: AlP + 3 H2O → Al(OH)3 + PH3

Organoaluminum Compounds and Related Hydrides There are numerous compounds with the molecular formulas AlR3 and AlR1.5Cl1.5.[30] These species generally have tetrahedral Al centers, e.g. "Trimethylaluminum" has the formula Al2(CH3)6 (see figure). For large organic groups, triorganoaluminum exists as three-coordinate monomers such as triisobutylaluminum. Such compounds are widely used in industrial chemistry, although they are often highly pyrophoric. Aside from the large organic groups, there are few analogues between organoaluminum and organoboron compounds. Structure of trimethylaluminum, a five-coordinate compound with carbon.

The most important aluminum hydride is lithium aluminum hydride (LiAlH4), which is used as a reducing agent in organic chemistry. Can be made from lithium hydride and aluminum trichloride:

4 LiH + AlCl3 → LiAlH4 + 3 LiCl Various useful derivatives of LiAlH4 are known, e.g. Sodium bis(2-methoxyethoxy)dihydroaluminate. The simplest hydride, aluminum or alanide, remains a laboratory curiosity. It is a polymer of formula (AlH3)n, in contrast to the corresponding borohydride of formula (BH3)2.

Aluminium

223

+1 and +2 oxidation states Although the vast majority of aluminum compounds have Al3+ centers, compounds with lower oxidation states are known and sometimes important as precursors to Al3+ species. Aluminum(I)AlF, AlCl, and AlBr are present in the gas phase when the trihalide is heated with aluminum. The AlI composition is unstable towards triiodide at room temperature:[31] 3 AlI → AlI3 + 2 Al A stable derivative of aluminum monoiodide is the cyclic adduct Al4I4(NEt3)4 formed with triethylamine. Also of theoretical interest, but of transient existence, are Al2O and Al2S. Al2O is obtained by heating the normal oxide Al2O3 with silicon to 1800 °C (3272 °F) in vacuo.[31] These materials quickly disproportionate with respect to the starting materials. Aluminum(II) Very simple Al(II) compounds are reported or observed in the reactions of Al metal with oxidizing agents. For example, aluminum monoxide, AlO, has been detected in the gas phase after an explosion[32] and in stellar absorption spectra[33]. Compounds of the formula R4Al2, in which R is a large organic ligand, are under further investigation.[34]

Analysis The presence of aluminum can be detected in a qualitative analysis using aluminum.

Applications General purpose Aluminum is the most common nonferrous metal.[35] World aluminum production in 2005 was 31.9 million tons. It surpassed that of any other metal except iron (837.5 million tons).[36] The forecast for 2012 is 42-45 million tons, driven by increased Chinese production.[37] Aluminum is almost always alloyed, which greatly improves its mechanical properties, especially when hardened. For example, aluminum foil and ordinary beverage cans are made up of 92% to 99% aluminum alloys.[38] The most important alloying elements are copper, zinc, magnesium, manganese and silicon (e.g. duralumin), and the contents of these other metals are in the range of a few percent by weight.[39] Some of the many uses of aluminum metal are: • Transportation (automobiles, airplanes, trucks, railcars, watercraft, bicycles, etc.) such as sheet, pipe, castings, etc. • Packaging (cans, foil, frames, etc.) • Construction (windows, doors , panels, building cables, etc.).[40] • A wide variety of household items, from kitchen utensils to baseball bats and clocks.[41] • Public lighting masts, sailboat masts, walking sticks, etc. • Outer casing for entertainment electronics, eg also device boxes. Photographic Equipment, MacBook Pro Case • Electrical transmission lines for power distribution

Aluminum foil for household use

• MKM and Alnico steel magnets • High purity aluminum (SPA, 99.980% to 99.999% Al) used in electronics and CDs.

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224

• Heatsinks for electronic devices such as transistors and CPUs. • Metal core copper laminate substrate used in high brightness LED lighting. • Aluminum powder is used in paint and fireworks, and as a solid fuel for rockets and termites. • Aluminum can react with hydrochloric acid or sodium hydroxide to produce hydrogen gas. • Several countries, including France, Italy, Poland, Finland, Romania, Israel and the former Yugoslavia, have issued coins minted from aluminum or aluminum-copper alloys.[42][43]

Austin "A40 Sports" with aluminum body (circa 1951)

• Some guitar models have aluminum diamond plates on the face of the instruments, usually chrome or black. Kramer Guitars and Travis Bean are known to have made guitars with aluminum necks, which give the instrument a very distinctive sound. Aluminum is generally alloyed: it is only used as a pure metal when corrosion resistance and/or machinability are more important than strength or hardness. A thin layer of aluminum can be applied to a flat surface by physical vapor deposition or (very rarely) chemical vapor deposition or other chemical means to form optical coatings and mirrors.

Transport of aluminum sheets from a foundry

Aluminum Compounds Because aluminum is abundant and most of its derivatives have low toxicity, aluminum compounds enjoy wide and sometimes industrial applications. Alumina Aluminum oxide (Al2O3) and its associated oxyhydroxides and trihydroxides are produced or extracted from ores on a large scale. Most of this material is converted into metallic aluminium. About 10% of the production capacity is used for other applications. A major use is as an absorbent, for example alumina removes water from hydrocarbons to enable downstream processes poisoned by moisture. Aluminum oxides are common catalysts for industrial processes, e.g. the Claus process for converting hydrogen sulfide to sulfur in refineries and for alkylating amines. Many industrial catalysts are "supported", which usually means that an expensive catalyst (e.g. platinum) is contained in a high surface area material such as metal. B. alumina, is dispersed. A very hard material (Mohs hardness 9), alumina is widely used as an abrasive and in the manufacture of applications that take advantage of its inertia, such as in high-pressure sodium lamps. Sulphates Various aluminum sulphates are used. Aluminum sulphate (Al2(SO4)3(H2O)18) is produced on an annual scale of several billion kilograms. About half of the production is used for water treatment. The next big application is papermaking. It is also used as a mordant, fire extinguisher, food additive, flame retardant, and leather tanning agent. Ammonium aluminum sulfate, also called ammonium alum, (NH4)Al(SO4)2 12H2O, is used as a mordant and for tanning leather.[6] Potassium aluminum sulfate ([Al(K)](SO4)2)(H2O)12 is used in a similar way. Consumption of both alums is declining.

Aluminum Chlorides Aluminum chloride (AlCl3) is used in petroleum refining and in the manufacture of synthetic rubber and polymers. Despite sharing a similar name, aluminum hydrochloride has fewer and very different uses, such as a hardener and antiperspirant. It is an intermediate product in the production of metallic aluminum. Niche Composites Given the scale of aluminum composites, a small-scale application can still be in the thousands of tons. One of the many compounds used at this intermediate stage is aluminum acetate, a salt used in solution as an astringent. Aluminum borate (Al2O3 B2O3) is used in the manufacture of glass and ceramics. Aluminofluorosilicate (Al2(SiF6)3) is used in the manufacture of synthetic gemstones, glass and ceramics. Aluminum phosphate (AlPO4) is used in the manufacture of glass and ceramic products, pulp and paper, cosmetics, paints and varnishes, and in the manufacture of dental cement. Aluminum hydroxide (Al(OH)3) is used as an antacid, mordant, in water purification, in the manufacture of glass and ceramics, and for impregnating fabrics. Lithium aluminum hydride is a powerful reducing agent used in organic chemistry. Organoaluminum compounds are used as Lewis acids and cocatalysts. For example, methylaluminoxane is a cocatalyst for the polymerization of Ziegler-Natta olefins to produce vinyl polymers such as polyethylene.

Aluminum Alloys in Structural Applications Aluminum alloys with a wide range of properties are used in engineering structures. Alloy systems are classified according to a numerical system (ANSI) or by names that indicate their main alloying components (DIN and ISO). The strength and durability of aluminum alloys varies greatly not only due to specific alloying ingredients, but also due to heat treatments and manufacturing processes. A lack of awareness of these issues has at times resulted in poorly engineered designs and given aluminum a bad name. An important structural limitation of aluminum alloys is their resistance to fatigue. Unlike steels, aluminum alloys do not have a well-defined fatigue limit, which means that even under very low cyclic loads, fatigue failure will eventually occur. This means that engineers must assess these stresses and design for a fixed life rather than an infinite life. Another important property of aluminum alloys is their sensitivity to aluminum foam heat. Heating in the workshop is made more difficult because, unlike steel, aluminum melts without first turning bright red. Therefore, flame forming requires a certain level of expertise as there is no visual indication of how close the material is to the melt. Like all construction alloys, aluminum alloys are also subject to internal stresses after heating processes such as welding and casting. The problem with aluminum alloys in this regard is their low melting point, which makes them more susceptible to warping caused by thermally induced stress relaxation. Controlled stress relief can be achieved during manufacture by heat treating parts in a furnace followed by gradual cooling, effectively annealing stresses. The low melting point of aluminum alloys has not prevented their use in rockets; including for use in building combustors where gases can reach 3500K. The Agena upper stage engine used a regeneratively cooled aluminum design for some parts of the nozzle, including the thermally critical area of the throat. Another alloy of some value is aluminum bronze (Cu-Al alloy).

225

Aluminium

History The ancient Greeks and Romans used aluminum salts as a mordant for dyes and as an astringent to heal wounds; Alum is still used as an astringent. In 1761, Guyton de Morveau suggested calling alum the base of alumina. In 1808, Humphry Davy identified the existence of a metallic base of alum, which he first named aluminum and later aluminum (see Etymology section below). The metal was first produced in an impure form in 1825 by Danish physicist and chemist Hans Christian Ørsted. He reacted anhydrous aluminum chloride with potassium amalgam and produced a tin-like piece of metal.[44] Friedrich Wöhler was aware of these experiments and cited them, but after repeating Ørsted's experiments he concluded that this metal was pure potassium. He performed a similar experiment in 1827 by mixing anhydrous aluminum chloride with potassium and producing aluminum.[44] Wöhler is generally credited with insulating aluminum (lat. alumen, alum). Furthermore, Pierre Berthier discovered aluminum in the mineral bauxite and successfully extracted it.[45]WP:NOTRS The French Henri Etienne Sainte-Claire de Wöhler described them in 1846 and described them at Piccadilly Circus, London, 1893, improvements were made in a book 1859 which most important of them there and one of the first statues to be cast with much more expensive aluminum instead of sodium. Potassium.[46] Presumably, Deville also had the idea of electrolyzing alumina dissolved in cryolite; Charles Martin Hall and Paul Héroult developed perhaps the most practical procedure after Deville. Before commercial power generation in the early 1880s and the Hall-Héroult process in the mid-1880s, aluminum was extremely difficult to extract from its various ores. This made pure aluminum more valuable than gold.[47] Aluminum bars were exhibited at the 1855 World's Fair.[48] Napoleon III of France is said to have held a banquet at which the distinguished guests received aluminum crockery while the others were content with gold.[49][50] Aluminum was chosen as the material for the 100 ounce (2.8 kg) foundation stone of the Washington Monument in 1884, at a time when an ounce (30 grams) was the daily wage of an average worker on the project.[51] Cast on December 6, 1884 in a lavish dedication ceremony, the cornerstone was the largest single piece of cast aluminum at a time when aluminum was as expensive as silver.[51] The Cowles companies shipped quantities of aluminum alloys to the United States and England in 1886 using foundries such as the Carl Wilhelm Siemens furnace. Charles Martin Hall of Ohio in the United States and Paul Héroult of France independently developed the Hall-Héroult electrolysis process, which made it cheaper to extract aluminum from ores and is now the most widely used process in the world. The Hall Trial, [55] started in 1888 with the financial support of Alfred E. Hunt, the Pittsburgh Reduction Company, now known as Alcoa. Héroult's process was produced in Switzerland by Aluminum Industrie, now Alcan, and British Aluminum, now Luxfer Group and Alcoa, in Switzerland from 1889 until 1896 in Scotland. Sydney, Australia, in the dome of the Secretary General's building. Many navies used aluminum superstructure for their ships; The 1975 fire aboard USS Belknap which destroyed her aluminum superstructure, as well as observation of battle damage to British ships during the Falklands War, prompted many navies to switch to steel superstructure. The Arleigh Burke class was the first American ship of its kind

226

Aluminum built entirely of steel. Aluminum wire was once widely used in household electrical wiring. Due to corrosion-related failures, there were several fires.

Etymology Two variants of the metal's name are in use today, aluminum and aluminum (in addition to the obsolete aluminum). The International Union of Pure and Applied Chemistry (IUPAC) adopted aluminum as the international standard name for the element in 1990, but three years later recognized aluminum as an acceptable variant. Therefore, your periodic table contains both.[56] IUPAC prefers the use of aluminum in its internal publications, although almost as many IUPAC publications use the notation aluminum.[57] Most countries use the aluminum notation. In the United States and Canada, the spelling aluminum predominates.[][58] The Canadian Oxford Dictionary prefers aluminum, while the Australian Macquarie Dictionary prefers aluminum. In 1926, the American Chemical Society officially decided to use aluminum in their publications; American dictionaries often refer to the spelling of aluminum as "mainly British".[59][60] The name aluminum derives from its status as an alum base. It is borrowed from Old French; its ultimate source, alum, in turn is a Latin word literally meaning "bitter salt."[61] The first citation in the Oxford English Dictionary for any word used as a name for this element is aluminum, which British chemist and inventor Humphry Davy used in 1808 for the metal he was attempting to electrolytically isolate from the mineral alumina. The quote is from the Philosophical Transactions of the Royal Society of London: "Had I been fortunate enough to obtain firmer evidence on the subject and the metallic substances sought, I would have suggested them silicon, aluminium, zirconium and glycium". [62] [63] Davy settled on aluminum when he published his Chemische Philosophie in 1812: it has not been obtained in a perfectly free state, although alloys have been obtained with other metallic substances sufficiently different to indicate the probable nature of aluminium. ' [64] But that same year, in a review of Davy's book, an anonymous contributor to the literary magazine Quarterly Review rejected aluminum and suggested the name aluminum, "so we take liberty to spell the word , versus aluminum, which one less." classical sound." Davy isolated himself.) However, the spelling was - one of the elements was not un then known, such as platinum, known to Europeans since the 16th century, molybdenum, discovered in 1778, and tantalum, discovered to be true in 1802. The -um suffix agrees with the universal spelling alumina for the oxide (as opposed to alumina), as lantana is the oxide of lanthanum, and magnesia, ceria, and thoria are the oxides of magnesium, cerium, and thorium, respectively new electrolytic process for making the Metal, Charles Martin Hall used the notation -um, despite his consistent use of the notation -ium in all patents. 55], which he presented between 1886 and 1903[67]. Therefore, it was suggested on Wikipedia: Avoid weasel words, that the spelling reflects an easier-to-pronounce word with one syllable less, or that the spelling in the leaflet is an error. Hall's mastery of metalworking ensured that aluminum spelling became the standard in North America.

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NFPA 704 health issues

Fire diamond for aluminum shot

Despite its natural occurrence, aluminum has no known function in biology. It is a remarkably non-toxic aluminum sulfate with an LD50 of 6207 mg/kg (oral, mouse), which is equivalent to 500 grams for an 80 kg person.[6] Despite its extremely low acute toxicity, the health effects of aluminum are of concern due to the element's widespread environmental and commercial presence. Some toxicity can be attributed to bone and central nervous system deposition, which is particularly increased in patients with renal impairment. Because aluminum competes with calcium for absorption, increased amounts of dietary aluminum may contribute to a reduction in skeletal mineralization (osteopenia) seen in preterm and stunted infants. At very high doses, aluminum can cause neurotoxicity and has been linked to impairment of blood-brain barrier function.[68] A small percentage of people are allergic to aluminum and experience contact dermatitis, indigestion, vomiting, or other symptoms when they come in contact with or ingest aluminum-containing products such as deodorants or antacids. In people without allergies, aluminum is not as toxic as heavy metals, but there is evidence of some toxicity when consumed in excess.[69] Although the use of aluminum cookware has not been shown to lead to aluminum toxicity in general, overconsumption of antacids containing aluminum compounds and overuse of aluminum-containing antiperspirants result in greater exposure. Studies have shown that consumption of acidic foods or aluminum-containing liquids significantly increases aluminum absorption,[70] and maltol has been shown to increase aluminum accumulation in nerve and bone tissue.[71] In addition, aluminum increases estrogen-related gene expression in laboratory-grown human breast cancer cells.[72] The estrogen-like effects of these salts led to their classification as metalloestrogens. The effect of aluminum in antiperspirants has been studied for decades with little evidence of skin irritation.[6] However, its presence in antiperspirants, colorants (such as aluminum lacquer) and food additives is controversial in some circles. While there is little evidence that normal aluminum exposure poses a risk for healthy adults,[73] some studies indicate risks associated with increased exposure to the metal.[74] Aluminum from food can be more readily absorbed than aluminum from water.[] Some researchers have expressed concerns that aluminum in antiperspirants may increase the risk of breast cancer,[] and aluminum has been controversially implicated as a factor in Alzheimer's disease.[] In water pollution in Camelford, several people consuming aluminum sulfate were involved. Research into long-term health effects is ongoing, but post-mortem scans of victims have found elevated levels of aluminum in the brain and further research has been commissioned to determine if there is an association with cerebral amyloid angiopathy [75] according to the Alzheimer's Society is the medical and scientific opinion that studies have not convincingly established a causal relationship between aluminum and Alzheimer's disease.[76] However, some studies, such as that from the PAQUID cohort,[] cite aluminum exposure as a risk factor for Alzheimer's disease. Some brain plaques have been found to contain higher concentrations of the metal. [ ] Research in this area has been inconclusive; Aluminum accumulation can be a consequence of the disease, and not a causative agent. In any case, if aluminum is toxic, it must be through a very specific mechanism, since total human exposure to the element in the form of natural soil clay and dust over a lifetime is enormous.[77][78] There is still no scientific consensus as to whether aluminum exposure can directly increase the risk of Alzheimer's disease.[76]

Aluminium

Effect on plants Aluminum is the main factor that reduces plant growth in acidic soils. Although generally benign for plant growth in neutral pH soils, the concentration of toxic Al3+ cations in acidic soils increases and disrupts root growth and function.[79][80][81][82] Most acidic soils are saturated with aluminum rather than hydrogen ions. Soil acidity is therefore a result of hydrolysis of aluminum compounds.[83] This concept of “corrected lime potential”[84] to determine the degree of base saturation in soils became the basis of methods used today in soil analysis laboratories to determine the “lime demand”[85] of soils.[86] The adaptation of wheat to aluminum tolerance is such that aluminum induces the release of organic compounds that bind harmful aluminum cations. Sorghum is believed to have the same tolerance mechanism. The first aluminum tolerance gene was identified in wheat. It has been shown that aluminum tolerance in sorghum is controlled by a single gene, as is the case in wheat.[87] This is not the case with all plants.

References [2] Aluminum monoxide [3] Aluminum iodide [56] IUPAC Periodic Table of the Elements (http://www.iupac.org/highlights/period-table-of-the-elements.html). iupac.org [57] Search for “aluminum” on the IUPAC website publication (http://www.google.com/search?q=aluminum&sitesearch=iupac.org). [58] Bremner, John Words About Words: A Dictionary for Writers and Others Who Care about Words, pp. 22–23. ISBN 0-231-04493-3. [62] "Aluminium", Oxford English Dictionary. ed. ALREADY. Simpson and ESC Weiner, Second Oxford Edition: Clarendon Press, 1989. OED Online Oxford University Press. Retrieved October 29, 2006. The citation appears as "1808 SIR H. DAVY in Phil. Trans. XCVIII. 353". The ellipsis in the citation is as it appears in the OED citation. [66], “In the United States the situation was more complicated. Noah Webster's 1828 dictionary contains only aluminum, although the standard spelling among American chemists during most of the nineteenth century was aluminum; it was the preferred version in The Century Dictionary of 1889 and is the only spelling in Webster's Unabridged Dictionary of 1913". [73] Gitelman, H.J. "Physiology of Aluminum in Man" (http://books.google.com/books? id=wRnOytsi8boC&pg=PA90), in Aluminum and Health, CRC Press, 1988, ISBN 0-8247-8026-4, p. 90 [76] Aluminum and Alzheimer's disease (http://alzheimers.org.uk/site/scripts /documents_info.php?documentID=99), The Alzheimer's Society, Accessed 30 January 2009. [86] Soil liming reduces aluminum toxicity to plants.

External Links • Aluminum (http://www.periodicvideos.com/videos/013.htm) to Periodic Table Videos (University of Nottingham) • CDC – NIOSH Pocket Guide to Chemical Hazards – Aluminum (http://www.cdc . gov/niosh/npg/npgd0022.html) • Electrolytic production (http://electrochem.cwru.edu/encycl/art-a01-al-prod.htm) • World primary aluminum production by country (http:// / www.indexmundi .com/en/commodities/minerals/aluminium/aluminum_table12.html) • Historical aluminum prices according to the IMF (http://www.indexmundi.com/commodities/?commodity=alumum&months= 300 ) • History of aluminum (http://www .world-aluminium.org/About+Aluminium/Story+of/In+history) - from the International Aluminum Institute website • Emedicine - Aluminum (http://www .emedicine .com/med/topic113.htm) • Der Short film ALUMINUM (1941) (http://www.archive.org/details/gov.archives.arc.38661) is available for free download from the Internet Archive [more]

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Mineral

230

Ore An ore is a type of rock that contains minerals with important elements, including metals. Minerals are obtained through mining; They are then refined to extract the valuable elements. The grade or concentration of a mineral or metal, as well as its mode of occurrence, directly affects the costs associated with extracting the mineral. Therefore, the cost of mining must be weighed against the value of the metal contained in the rock to determine which ore can be processed and which ore is too low grade to be worth mining. Metallic minerals are usually oxides, sulfides, silicates, or "native" metals (such as native copper) not typically concentrated in the earth's crust, or "noble metals" (which do not typically form compounds), such as e.g. gold. Ores must be processed to extract the metals of interest from waste rock and ores. Orebodies are formed by a variety of geological processes. The process of mineral formation is called mineral genesis.

Iron Ore (Banded Iron Formation)

Ore Occurrence An ore occurrence is an accumulation of ore. However, this is distinct from a mineral resource as defined by the classification criteria for mineral resources. An ore deposit is a deposit of a specific type of mineral. Most ore deposits are named after their location (e.g. Witswatersrand, South Africa) or an explorer (e.g. Kambalda nickel shoots are named after drill bits) or on a whim after a historical figure. , a prominent person, something from mythology (phoenix, octopus, snake leopard, etc.), or the codename of the resource company that found it (e.g. MKD-5 is the internal name of the five dollar coin). Mount Keith cents).

Manganese Mineral - Psilomel (Size: 6.7 x 5.8 x 5.1 cm)

Classification of Mineral Occurrences Mineral occurrences are classified according to various criteria developed through the study of economic geology or mineral genesis. The following reviews are typical.

Lead Ore - Galena and Winkelsite (Size: 4.8 x 4.0 x 3.0 cm)

Hydrothermal Epigenetic Deposits • Mesothermal vein gold deposits typical of Golden Mile, Kalgoorlie • Archean conglomerate gold and uranium deposits typical of Elliot Lake, Canada and Witwatersrand, South Africa • Carlin-style gold deposits, including; • Stockwork epithermal vein deposits

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• Granite-related hydrothermal deposits • IOCG or iron oxide copper-gold deposits typical of the Olympic Dam supergiant Cu-Au-U deposit • Porphyry copper +/- gold +/- molybdenum +/- silver -Deposits • Copper-Gold +/- related intrusives (tin-tungsten) typical of the Tombstone, Arizona deposits • Hydromagmatic magnetite iron ore deposits and skarns • Copper-lead-zinc-tungsten scoff ore deposits etc. Nickel-Cobalt-Platinum -Deposits

Gold Ore (Size: 7.5 x 6.1 x 4.1 cm)

• nickel-copper-iron-PGE magmatic deposits, including: • accumulated vanadiferous or platinum-bearing magnetite or chromite • accumulated hard-rock titanium (ilmenite) deposits • komatiite-hosted Ni-Cu-PGE deposits • subvolcanic feeder subtype, typified by Noril 'sk-Talnakh and Thompson Belt, Canada • Ni-Cu-PGE related intrusives typical of Voisey's Bay, Canada and Jinchuan, China • Lateritic nickel ore deposits, examples include Goro and Acoje (Philippines) and Ravensthorpe, Western Australia. Volcanic deposits • Volcanic-hosted bulk sulphides (VHMS) Cu-Pb-Zn including; • Examples are Teutonic Bore and Golden Grove, Western Australia • Besshi type • Kuroko type

Wagon used to transport ore from a mine on display at the Historical Archives and Mining Museum in Pachuca, Mexico.

Metamorphic revised deposits • Paramagmatic iron-chromium oxide deposits in podiform serpentinite typical of Savage River, Tasmanian iron ore, Coobina chromite deposit • Broken Hill type Pb-Zn-Ag, considered a class of revised SEDEX deposits carbonatite-alkaline-igneous • Phosphorus-Tantalite-Vermiculite (Phalaborwa, South Africa) • Rare earth elements: Mount Weld, Australia and Bayan Obo, Mongolia • Diamond embedded in diatremes in kimberlite, lamproite or lamprophyre

Mineral

232 Sedimentary deposits • Iron ore deposits from banded iron formation, including • Channel or pisolite iron ore deposits • Heavy mineral sands and other sand dune deposits • Alluvial deposits of gold, diamonds, tin, platinum, or sand black • Alluvial zinc oxide deposit type: Single example Scorpion Zinc Sedimentary Hydrothermal Deposits • SEDEX

Close-up of a sample from the Upper Michigan Banded Iron Formation. The scale bar is 5.0 mm.

• Lead-zinc-silver typical of Red Dog, McArthur River, Mount Isa, etc. • Stratiform copper in arkoses and shales typical of the Zambian Copper Belt. • Layered tungsten typical of the Ore Mountain deposits, Czechoslovakia • Gold deposits in exhaling spilite chert • Mississippi Valley-type zinc-lead (MVT) deposits • Hematite-iron ore deposits with altered banded iron formation Astrobleme-related minerals • Sudbury Basin nickel and copper , Ontario, Canada

Extraction The basic extraction of mineral deposits follows the steps below; 1. Prospecting or exploration to find and define the extent and value of the mineral where it is found ("mineral bodies"). 2. Complete a resource estimate to mathematically estimate the size and grade of the deposit

Some mineral deposits of the world

3. Complete a Pre-Feasibility Study to determine the theoretical economics of the mineral deposit. This will determine early on whether additional investment in estimates and engineering studies is warranted and will identify key risks and areas for future work. 4. Conduct a feasibility study to assess the financial feasibility, technical and financial risks and project viability and make a decision to develop or abandon a proposed mine project. This includes mine planning to assess the economically mineable portion of the deposit, metallurgy and ore mineability, marketing and payment of ore concentrates, engineering, milling and infrastructure costs, capital and financial requirements, and a cradle to grave analysis of the mine. Potential. from the first excavation to the salvage. 5. Development to provide access to an ore deposit and construction of mine works and equipment 6. Active operation of the mine 7. Reclamation to recover land where a mine was suitable for future use

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Trade Minerals (metals) are traded internationally and make up a significant part of international commodity trading in terms of both value and quantity. This is because the global distribution of minerals is uneven and crowded out by peak demand locations and smelting infrastructure. Most base metals (copper, lead, zinc, nickel) are traded internationally on the London Metal Exchange, with smaller stocks and metals exchanges overseen by the COMEX and NYMEX exchanges in the US and the Shanghai Futures Exchange in China.

Imports of minerals and metals in 2005

Iron ore is negotiated between the customer and the producer, although different reference prices are set between large miners and large consumers on a quarterly basis, which sets the stage for smaller players. For other smaller commodities, there are no international clearinghouses or reference prices, and most prices are negotiated between individual suppliers and customers. This often makes the pricing of minerals of this type opaque and difficult. Such metals include lithium, niobium tantalum, bismuth, antimony and rare earths. Most of these commodities are also dominated by one or two major suppliers with >60% of world reserves. The London Metal Exchange intends to add uranium to its list of collateralised metals. The World Bank reports that China was the top importer of minerals and metals in 2005, followed by the United States and Japan. [citation required]

Important minerals • • • • • • • • • • • • • • • • • •

Argentite: Ag2S for silver extraction Barite: BaSO4 Bauxite Al(OH)3 and AlOOH dried to Al2O3 for aluminum extraction Beryl: Be3Al2(SiO3)6 Bornite: Cu5FeS4 Cassiterite: SnO2 Chalcocite: Cu2S for copper extraction Chalcopyrite: CuFeS2 Chromite : (Fe , Mg) Cr2O4 to produce chromium Cinnabar: HgS to produce mercury Cobaltite: (Co,Fe)AsS Columbite-Tantalite or Coltan: (Fe,Mn)(Nb,Ta)2O6 Dolomite: CaMg(CO3 )2 Galena: PbS Gold: Au , typically associated with quartz or as placer deposits Hematite: Fe2O3 Ilmenite: FeTiO3 Magnetite: Fe3O4 Malachite: Cu2CO3(OH)2 Molybdenite: MoS2 Pentlandite:(Fe,Ni)9S8 Pyrolusite: MnO2 Scheelite: CaWO4

• Sphalerite: ZnS • Uraninite (pitchblende): UO2 for the production of metallic uranium

Mineral

234 • Wolframita: (Fe, Mn)WO4

References Further reading DILL, H.G. (2010) The Mineral Occurrence Classification Scheme in "Checkerboard: Aluminum to Zirconium Mineralogy and Geology", Earth-Science Reviews, Volume 100, Numbers 1-4, June 2010, Pages 1-420 (http://www.hgeodill.de/ Card-Checkerboard-Classification-Scheme.htm)

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carbon carbon C 6

Boron ← carbon → nitrogen ↑

C ↓ Si Carbon on the periodic table Appearance clear (diamond) and black (graphite)

General Properties of Carbon Spectral Lines Name, Symbol, Number

carbon, C, 6

pronunciation

/kɑrbən/

item category

polyatomic nonmetal

group, period, block

14, 2, p.

standard atomic weight

12.011(1)

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236 Electronic configuration

[Kante] 2s2 2p2 2, 4

history [1]

discovery

Egyptians and Sumerians

Recognized as item by

Antonio Lavoisier

[2]

(3750 aC)

(1789)

Phase of physical properties

fest

Density (near room temperature)

amorphous:

Density (near room temperature)

Diamant: 3,515 g·cm−3

Density (near room temperature)

Graphit: 2,267 g cm-3

sublimation point

3915K, 3642°C, 6588°F

triple point

4600K (4327°C), 10800

heat of fusion

117 (Graphite) kJ mol−1

molar heat capacity

6.155 (Diamond) 8.517 (Graphite) J mol−1 K−1

[3]

1,8–2,1 g·cm−3

[][]

kPa

Atomic properties [4]

[5]

oxidation states

4, 3

electronegativity

2.55 (Pauling Scale)

Ionization energies (more)

1.: 1086.5 kJ mol-1

, 2, 1

2.: 2352,6 kJ mol-1 3.: 4620,5 kJ mol-1 Kovalenter Radius

77 (sp³), 73 (sp²), 69 (sp) pm

Radio Van der Waals

170 hours of miscellaneous

crystal structure

[6]

, 0, −1, −2, −3, −4

Diamond

(diamond of course)

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237 hexagonal simples

(graphite, black) [7]

magnetic request

diamagnetic

thermal conductivity

900–2300 (Diamant) 119–165 (Graphit)W·m–1·K–1

thermal expansion

(25°C) 0.8 (Diamond)

Speed of Sound (thin bar)

(20 °C) 18350 (Diamant) m·s−1

modulus of elasticity

1050 (Diamond)

Schneidmodul

478 (Diamond)

Volumenmodul

442 (Diamond)

poison ratio

0.1 (Diamond)

Mohs hardness

10 (Diamond) 1-2 (Graphite)

CAS registration number

7440-44-0

[8]

[8] [8]

µm·m−1·K−1

GPa

GPa GPa

[8]

More stable isotopes Main article: Iso-carbon isotopes

THE

Half-life DM SD (MeV) SD

sin

20 minutes

C 98,9%

K 1,1 %

12 13

course c

0,96

C is stable at 6 neutrons C is stable at 7 neutrons

5730 years

−

0,15 0

Norte

Carbon (Latin: carbo "carbon") is the chemical element with the symbol C and atomic number 6. As a member of the 14th group of the periodic table, it is non-metallic and tetravalent and provides four electrons to form bonds. There are three naturally occurring isotopes, 12C and 13C are stable, while 14C is radioactive and decays with a half-life of about 5730 years.[] Carbon is one of the few elements known from ancient times.[] There are several allotropes of Carbon, the best known of which are graphite, diamond, and amorphous carbon. [ ] The physical properties of carbon vary greatly with the allotrope. For example, diamond is highly transparent while graphite is opaque and black. Diamond is the hardest known natural material, while graphite is soft enough to form a line on paper (hence its name, from the Greek word "γράφω" meaning "to write"). Diamond has a very low electrical conductivity, while graphite is a very good conductor. Under normal conditions, diamond, carbon nanotubes, and graphene have the highest thermal conductivities of any known material. All carbon allotropes are solid under normal conditions, with graphite being the thermodynamically most stable form. They are chemically stable and require high temperatures to react with oxygen as well. The most common oxidation state of carbon in inorganic compounds is +4, while +2 is found in carbon monoxide and other carbonyl complexes of transition metals. The main sources of inorganic carbon are limestone, dolomites, and carbon dioxide, but significant amounts are found in organic deposits of coal, peat, petroleum, and methane clathrates. The carbon is formed more

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compounds than any other element, with nearly ten million pure organic compounds described to date, which in turn are a small fraction of such compounds that are theoretically possible under standard conditions. [ ] Carbon is the 15th most abundant element in the earth's crust and the fourth most abundant element in the universe after hydrogen, helium and oxygen. It is present in all known forms of life, and in the human body, carbon is the second most abundant element by mass (about 18.5%), after oxygen.[9] This abundance, along with its unique variety of organic compounds and its unusual ability to form polymers at temperatures common on Earth, make this element the chemical basis of all known life.

features

Theoretically predicted carbon phase diagram

The various forms, or allotropes, of carbon (see below) include the hardest naturally occurring substance, diamond, and one of the softest known substances, graphite. In addition, it has an affinity for bonding to other small atoms, including other carbon atoms, and is capable of forming multiple stable covalent bonds with such atoms. As a result, carbon is known to form nearly ten million different compounds; the vast majority of all chemical compounds. [ ] Carbon also has the highest sublimation point of any element. At atmospheric pressure it has no melting point as its triple point is 10.8 ± 0.2 MPa and 4600 ± 300 K (~4330 °C or 7820 °F),[][] then sublimes at around 3900 K. [][10]

The carbon sublimes in a carbon arc at a temperature of approximately 5,800 K (5,530 °C; 9,980 °F). Therefore, regardless of its allotropy, carbon remains solid at higher temperatures than metals with higher melting points such as tungsten or rhenium. Although thermodynamically susceptible to oxidation, carbon resists oxidation more effectively than elements such as iron and copper, which are weaker reducing agents at room temperature. Carbon compounds form the basis of all known life on Earth, and the carbon-nitrogen cycle provides some of the energy produced by the Sun and other stars. Although it forms an extraordinary variety of compounds, most forms of carbon are relatively unreactive under normal conditions. At standard temperature and pressure, it resists all but the strongest oxidants. It does not react with sulfuric acid, hydrochloric acid, chlorine or alkali. At elevated temperatures, carbon reacts with oxygen to form carbon oxides and reduces metal oxides, such as iron oxide, to metal. This exothermic reaction is used in the steel industry to control the carbon content of steel: Fe 3O 4+ 4 C → 3 Fe(s) + 4 CO(g)(s) with sulfur to form carbon disulfide and with water vapor in coal - gaseous reaction: C (s) + H2O(g) → CO(g) + H2(g). Carbon combines with some metals at high temperatures to form metal carbides such as iron carbide, cementite in steel and tungsten carbide, which are widely used as abrasives and to create hard edges for cutting tools. As of 2009, graphene appears to be the strongest material ever tested. [] However, the graphite separation process will require some technological developments before it is cost effective enough to be used in industrial processes. extremes:

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Synthetic nanocrystalline diamond is the hardest known material [11].

Graphite is one of the softest known materials.

Diamond is the ultimate abrasive.

Graphite is a very good lubricant that has excellent lubricity.

[13] Diamond is an excellent electrical insulator and has the highest electrical breakdown field of any known material.

Graphite is an electrical conductor.

[12]

[14]

Diamond is the best-known natural conductor of heat.

Some forms of graphite are used for thermal insulation (e.g. firebreaks and heat shields), but some other forms are good conductors of heat.

The diamond is very transparent.

Graphite is opaque.

Diamond crystallizes in the cubic system.

Graphite crystallizes in the hexagonal system.

Amorphous carbon is completely isotropic.

Carbon nanotubes are among the most anisotropic materials ever made.

[fifteen]

Allotropes Atomic carbon is a very short-lived species and therefore carbon is stabilized in various polyatomic structures with different molecular configurations called allotropes. The three relatively well-known allotropes of carbon are amorphous carbon, graphite, and diamond. Fullerenes, once considered exotic, are now commonly synthesized and used in research. these include buckyballs,[][] carbon nanotubes,[] carbon nanosprouts[] and nanofibers.[16][17] Several other exotic allotropes have also been discovered, such as B. Lonsdaleit,[] glassy carbon,[] carbon nanofoam,[18] and linear acetylenic carbon (carbine).[] The amorphous form is a multitude of carbon atoms in a noncrystalline form., irregular glassy state that is essentially graphite but none crystalline macrostructure supported. It is in powder form and is the main component of substances such as charcoal, soot (soot) and activated carbon. At normal pressure, carbon takes the form of graphite, in which each atom is trigonally bonded to three others in a plane formed by fused hexagonal rings, as in aromatic hydrocarbons.[19] The resulting network is two-dimensional and the resulting flat sheets are loosely stacked and held together by weak van der Waals forces. This gives graphite its smoothness and cutting properties (blades slide easily over each other). Due to the delocalization of one of the outer electrons of each atom to form a π cloud, graphite conducts electricity, but only in the plane of each covalently bonded layer. As a result, carbon has a lower electrical conductivity than most metals. The delocalization also explains the energetic stability of graphite compared to diamond at room temperature.

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At very high pressures, carbon forms the most compact allotrope of diamond and is almost twice the density of graphite. Here, each atom is tetrahedrally connected to four others, forming a three-dimensional network of folded six-membered atomic rings. Diamond has the same cubic structure as silicon and germanium and is the hardest natural material in terms of scratch resistance due to the strength of the carbon-carbon bonds. Contrary to popular belief that “diamonds are eternal”, under normal conditions they are thermodynamically unstable and turn into graphite. . Under certain conditions, carbon crystallizes as lonsdaleite. This form has a hexagonal crystal lattice in which all the atoms are covalently bonded. Therefore, all properties of Lonsdaleit are similar to those of diamond.[]

240

Some carbon allotropes: a) diamond; b) graphite; c) Lonsdaleit; d–f) fullerenes (C60, C540, C70); g) amorphous carbon; h) carbon nanotubes.

Fullerenes have a structure similar to graphite, but instead of a purely hexagonal package, they also contain pentagons (or even heptagons) of carbon atoms that bend the plate into spheres, ellipses, or cylinders. The properties of fullerenes (divided into buckyballs, buckytubes, and nanobuds) have not yet been fully analyzed and represent an intense area of research on nanomaterials of fullerenes are similar. Bucky Balls are fairly large molecules made entirely of trigonally bonded carbon, forming spheroids (the most famous and simplest is the football-shaped buckminsterfullerene C60). [] Carbon nanotubes are structurally similar to bucky balls, except that each atom is trigonally bonded in a curved layer that forms a hollow cylinder (the spheres are covalently bonded to the outer wall of a nanotube), combining the properties of both into a single structure. [] Of the other allotropes discovered, carbon nanofoam is a ferromagnetic allotrope discovered in 1997. It consists of a collection of low-density clumps of carbon atoms bound together in a loose three-dimensional network in which the atoms are linked trigonally to six- and seven-membered rings. It is one of the lightest solids known, with a density of about 2 kg/m3.[20] Likewise, glassy carbon contains a high proportion of closed porosity,[] but unlike normal graphite, graphite layers do not stack like book pages, but rather are arranged randomly. Linear acetylenic carbon[] has the chemical structure[] -(C:::C)n-. The carbon in this modification is linear with sp orbital hybridization and is a polymer with alternating single and triple bonds. This type of carabiner is of great interest for nanotechnology because its modulus of elasticity is forty times greater than that of the hardest known material: diamond.[21]

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Occurrence Carbon is the fourth most common chemical element in the universe after hydrogen, helium and oxygen. Carbon is abundant in the sun, stars, comets, and in the atmosphere of most planets. Some meteorites contain microscopic diamonds that formed when the solar system was still a protoplanetary disk. Microscopic diamonds can also be formed by the intense pressure and high temperature at meteorite impact sites.[22] Along with the oxygen in carbon dioxide, carbon is found in the Earth's atmosphere (about 810 gigatonnes of carbon) and is dissolved in all bodies of water (about 36,000 gigatons of carbon). About 1,900 gigatonnes of carbon are present in the biosphere. Hydrocarbons (such as coal, oil, and natural gas) also contain carbon: coal "reserves" (not "resources") are about 900 gigatons and oil reserves are about 150 gigatons. Proven sources of natural gas are about 1751012 cubic meters (equivalent to about 105 gigatons of carbon), but it is estimated that there are also about 9001012 cubic meters of "unconventional" gas such as shale gas, which represents about 540 gigatons of carbon.[23 ] Carbon is also identified as methane hydrate in included in the polar regions and under the seas. Various estimates have been made of the amount of carbon this represents: 500 to 2,500 Gt[24] or 3,000 Gt.[25] (In the past, levels of hydrocarbons were higher. Between 1751 and 2008, about 347 gigatonnes of carbon were released into the atmosphere as carbon dioxide from burning fossil fuels.[26])

Graphiterz

Raw diamond crystal.

Carbon is an important component in very large masses of carbonate rocks (limestone, dolomite, marble, etc.). Coal is the largest commercial source of mineral carbon, accounting for 4,000 gigatonnes or 80% of fossil carbon fuel.[27] It is also rich in carbon; for example, anthracite contains between 92 and 98%.[28] "Today" (1990s) dissolved sea surface In terms of individual carbon allotropes, graphite occurs in large concentrations of inorganic carbon (from amounts in the United States (mainly New York and Texas), GLODAP climatology), Russia, Mexico, Greenland and India Natural diamonds are found in kimberlite rock found in ancient volcanic "necks" or "tubes". Most diamond deposits are in Africa, particularly in South Africa, Namibia, Botswana, the Republic of the Congo and Sierra Leone. There are also deposits in Arkansas, Canada, the Russian Arctic, Brazil, and northern and western Australia. Diamonds are now also being recovered from the seabed at the Cape of Good Hope. Although diamonds occur naturally, approximately 30% of all industrial diamonds used in the US are synthetically produced.

Carbon-14 is formed in the upper troposphere and stratosphere at altitudes of 9 to 15 km by a cosmic ray-triggered reaction.[29] Thermal neutrons are produced, which collide with the nitrogen-14 nuclei, forming carbon-14 and a proton.

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Isotopes Carbon isotopes are atomic nuclei that contain six protons plus a number of neutrons (ranging from 2 to 16). Carbon has two stable natural isotopes.[] The isotope carbon-12 (12C) makes up 98.93% of the carbon on earth, while carbon-13 (13C) makes up the remaining 1.07%.[] The concentration of 12C is uniformly larger in biological materials because biochemical reactions discriminate against 13C.[30] In 1961, the International Union of Pure and Applied Chemistry (IUPAC) adopted the carbon-12 isotope as the basis for atomic weights.[31] Carbon is identified in NMR experiments using the 13C isotope. Carbon 14 (14C) is a naturally occurring radioisotope found on Earth in trace amounts up to 1 part per trillion (0.0000000001%), primarily in the atmosphere and in surface deposits, particularly peat and other organic materials.[32] This isotope decays by β emission of 0.158 MeV. Because of its relatively short half-life of 5,730 years, 14C is virtually absent in ancient rocks, but is formed in the upper atmosphere (lower stratosphere and upper troposphere) through the interaction of nitrogen with cosmic rays.[33] The abundance of 14C in the atmosphere and in living organisms is nearly constant, but predictably decreases in their bodies after death. This principle is used in radiocarbon dating, invented in 1949 and widely used to age carbonaceous materials up to about 40,000 years.[34][35] There are 15 known carbon isotopes and the shortest-lived is 8C, which decays by proton emission and alpha decay and has a half-life of 1.98739 x 10−21 s.[36] Exotic 19C has a nuclear halo, meaning that its radius is significantly larger than would be expected if the nucleus were a constant-density sphere.[37]

Star Formation The formation of the atomic nucleus from carbon requires an almost simultaneous triple collision of alpha particles (helium nuclei) in the core of a giant or supergiant star, known as the triple alpha process, as a product of other nuclear energy reactions. . Fusing helium with hydrogen or another helium nucleus produces lithium-5 and beryllium-8, respectively, which are very unstable and break down into smaller nuclei almost immediately. [ ] It is under conditions of temperatures above 100 megakelvins and helium concentration that the rapid expansion and cooling of the early Universe was prevented and therefore no significant carbon was produced during the Big Bang. Instead, the interiors of the stars in the horizontal branch convert three helium nuclei to carbon through this triple alpha process. [] In order to be available for the formation of life as we know it, this carbon must then spread into space. as dust, in supernova explosions, as part of the material that later forms second and third generation star systems that formed planets from that dust.[38] The solar system is one of those third generation star systems. Another fusion mechanism that powers stars is the CNO cycle, in which carbon acts as a catalyst to allow the reaction to take place. Rotational transitions of different isotopic forms of carbon monoxide (e.g. 12CO, 13CO, and C18O) are detectable in the submillimetre wavelength range and are used to study newly formed stars in molecular clouds.[39]

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Carbon cycle Under terrestrial conditions, the conversion of one element into another is very rare. Therefore, the amount of carbon on Earth is effectively constant. So processes that use carbon have to get it somewhere and dispose of it somewhere else. The paths taken by carbon in the environment form the carbon cycle. For example, plants absorb carbon dioxide from their environment and use it to create biomass, as in carbon respiration or the Calvin cycle, a process of carbon fixation. Animals eat some of this biomass, while animals exhale some of the carbon in the form of carbon dioxide. The carbon cycle is much more complicated than this short circuit; For example, some carbon dioxide dissolves in the oceans; Dead plant or animal matter can be turned into oil or charcoal, which can be burned to release carbon when not consumed by bacteria.[40][41]

Carbon cycle diagram. The black numbers indicate how much carbon is stored in billions of tons in different reservoirs ("GtC" stands for gigatons of carbon; numbers are around 2004). The purple numbers indicate how much carbon is moved between pools each year. The sediments defined in this diagram do not include the ~70 million GtC of carbonate and kerogen rocks.

Compounds Organic Compounds Carbon has the ability to form very long chains of interconnected C-C bonds. This property is called concatenation. Carbon-carbon bonds are strong and stable. This property allows carbon to form an almost infinite number of compounds; In fact, there are more known carbon-containing compounds than all other chemical elements combined except hydrogen (because almost all organic compounds also contain hydrogen).

Structural formula of methane, the simplest organic compound.

The simplest form of an organic molecule is the hydrocarbon, a large family of organic molecules composed of hydrogen atoms bonded to a chain of carbon atoms. Chain length, side chains and functional groups affect the properties of organic molecules.

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Carbon is found in all known organic life and is the basis of organic chemistry. When bound to hydrogen, it forms several important hydrocarbons for industry as refrigerants, lubricants, solvents, as a chemical feedstock for the manufacture of plastics and petrochemicals, and as fossil fuels. In combination with oxygen and hydrogen, carbon can form many groups of important biological compounds, including sugars, lignans, chitins, alcohols, fats and aromatic esters, carotenoids, and terpenes. With nitrogen it forms alkaloids, with sulfur also antibiotics, amino acids and rubber products. The addition of phosphorus to these other elements creates DNA and RNA, the carriers of life's chemical code, and adenosine triphosphate (ATP), the primary energy transfer molecule in all living cells.

Inorganic Compounds

Relationship between the carbon cycle and the formation of organic compounds. In plants, carbon dioxide formed by carbon fixation can combine with water during photosynthesis (green) into organic compounds that can be used and converted by plants and animals.

Usually, carbonaceous compounds associated with minerals or that do not contain hydrogen or fluorine are treated separately from classical organic compounds; however, the definition is not rigid (see previous reference articles). Among them are the simple carbon oxides. The best-known oxide is carbon dioxide (CO2). This was once a major component of the paleoatmosphere, but is now a minor component of Earth's atmosphere.[42] When dissolved in water, it forms carbonic acid (H 2 CO [43] 3), but like most compounds with multiple oxygen single bonds at a carbon, it is unstable. However, this intermediate generates resonance-stabilized carbonate ions. Some important minerals are carbonates, mainly calcite. Carbon disulfide (CS 2) is similar. The other common oxide is carbon monoxide (CO). It is produced by incomplete combustion and is a colorless and odorless gas. Each of the molecules contains a triple bond and is quite polar, resulting in a tendency to permanently bind to hemoglobin molecules and displace oxygen, which has a lower binding affinity. Cyanide (CN–) has a similar structure but behaves very much like a halide (pseudohalogen) ion. For example, it can form the molecule cyanogen nitride ((CN)2), similar to diatomic halides. Other rare oxides are carbon suboxide (C 3O [46] 2), unstable dicarbonate monoxide (C2O),[47][48] carbon trioxide (CO3),[49][50] cyclopentanepentone (C5O5)[51 ] cyclohexanehexone (C6O6). ),[51] and methyl anhydride (C12O9). Carbon forms carbides (C4-) or acetylides (C2-2) with reactive metals such as tungsten to form alloys with high melting points. These anions are also associated with methane and acetylene, both of which are very weak acids. With an electronegativity of 2.5,[52] carbon preferentially forms covalent bonds. Some carbides are covalent.

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reticulated, like carborundum (SiC), which resembles diamond.

Organometallic Compounds Organometallic compounds are defined as containing at least one carbon-metal bond. There is a wide range of such connections; Major classes include simple metal alkyls (e.g. tetraethyllead), η2-alkene compounds (e.g. Zeise salt) and η3-allyl compounds (e.g. allylpalladium chloride dimer); metallocenes containing cyclopentadienyl ligands (e.g. ferrocene); and transition metal carbene complexes. There are many metallic carbonyls (e.g. tetracarbonyl nickel); Some researchers consider the carbon monoxide ligand to be purely inorganic rather than organometallic. Although it is clear that carbon forms exclusively four bonds, an interesting compound containing a six-coordinate octahedral carbon atom has been reported. The cation of the compound is [(Ph3PAu)6C]2+. This phenomenon has been attributed to the aurophilicity of gold ligands.[53]

History and Etymology The English name carbon derives from the Latin carbo for charcoal and charcoal,[54] from which also derives the French charbon, meaning charcoal. In German, Dutch and Danish, the names for carbon are carbon, koolstof and kulstof, which literally means carbon substance. Carbon was discovered in prehistoric times and was known to early human civilizations in the form of soot and coal. Diamonds were probably already 2500 BC. known. C. China, while carbon in the form of charcoal was produced in Roman times using the same chemistry as today, by heating wood in a clay-covered pyramid to exclude air.[][55] Antoine Lavoisier in his youth

In 1722, René Antoine Ferchault de Réaumur showed that iron is converted into steel by the incorporation of a substance now known as carbon.[56] In 1772, Antoine Lavoisier proved that diamonds are a form of carbon; when he burned samples of coal and diamonds and found that neither produced water and both emitted the same amount of carbon dioxide per gram. In 1779 [57] Carl Wilhelm Scheele showed that graphite, thought to be a form of lead, was identical to carbon, but with a small admixture of iron, and that it gave "atmospheric acid" (his name for carbon). dioxide) when oxidized with nitric acid.[58] In 1786, French scientists Claude Louis Berthollet, Gaspard Monge, and CA Vandermonde confirmed that graphite was composed primarily of carbon by oxidizing it to oxygen in the same way Carl Wilhelm Scheele Lavoisier had done diamond.[59] Again some iron remained, which the French scientists thought was necessary for the structure of graphite. However, in their publication they suggested the name carbone (lat. carbonum) for the element graphite, which escapes in gaseous form when graphite is burned. Antoine Lavoisier later included carbon as an element in his 1789 book.[60] A new allotrope of carbon, fullerene, discovered in 1985[61] includes nanostructured shapes such as buckyballs and nanotubes.[] Its discoverers, Robert Curl, Harold Kroto, and Richard Smalley, were awarded the 1996 Nobel Prize in Chemistry.[ 62 ] The resulting renewed interest in new forms led to the discovery of more exotic allotropes, including glassy carbon, and the realization that "amorphous carbon" is not strictly amorphous.[]

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Production Graphite Commercially exploitable natural deposits of graphite exist in many parts of the world, but the economically most important sources are in China, India, Brazil and North Korea. Graphite deposits are metamorphic in origin, found associated with quartz, mica and feldspars in shales, gneisses and sandstones and limestones that have been altered into a lens or vein form, sometimes a meter or more thick. The graphite deposits at Borrowdale, Cumberland, England were originally so large and pure that up until the 19th century pencils were made simply by cutting blocks of natural graphite into strips before wrapping them in wood. Today, the smallest deposits of graphite are mined by crushing the parent rock and floating the lighter graphite on water.[63] There are three types of natural graphite: amorphous, flake, or crystalline flakes and veins or lumps. Amorphous graphite is the lowest quality and most common. Contrary to science, "amorphous" in industry refers to a very small crystal size rather than a complete lack of crystalline structure. Amorphous is used for low-grade graphite products and is the cheapest graphite. Large deposits of amorphous graphite are found in China, Europe, Mexico and the United States. Flake graphite is rarer and of higher quality than amorphous; occurs as separate plates crystallized in metamorphic rock. Flake graphite can cost four times the price of amorphous graphite. Good quality flakes can be processed into expandable graphite for many applications, such as flame retardants. The most important deposits are in Austria, Brazil, Canada, China, Germany and Madagascar. Grain or granular graphite is the rarest, most valuable and highest quality type of natural graphite. It occurs in veins along intrusive contacts in solid floes and is mined commercially only in Sri Lanka.[63] According to USGS, the world production of natural graphite in 2010 was 1.1 million tons, of which China contributed 800,000 tons, India 130,000 tons, Brazil 76,000 tons, North Korea 30,000 tons and Canada 25,000 tons. No natural graphite mining has been reported in the United States, but 118,000 tons of synthetic graphite were produced in 2009 with an estimated value of US$998 million.[63]

Diamond The diamond supply chain is controlled by a limited number of powerful corporations and is also highly concentrated in a few locations around the world (see figure). Only a very small part of diamond ore consists of real diamonds. The ore is crushed, taking care not to destroy larger diamonds in the process. Diamond production in 2005, and then the particles are sorted by density. Today, diamonds are located in the diamond-rich density fraction using X-ray fluorescence, after which the last sorting steps are carried out manually. Before the widespread use of X-rays, separation was done with grease tape; Diamonds have a greater tendency to stick to fat than the other minerals in the ore.[64] Historically, diamonds have only been found in alluvial deposits in southern India.[65] Since its discovery in the 9th century BC, India has been Chr. World leader in diamond production. c.[66] to the mid-18th century AD C., but the commercial potential of these sources had been exhausted by the late 18th century, by which time India was eclipsed by Brazil, where the first non-Indian diamonds were found in 1725 .[67] The production of diamonds from primary deposits (kimberlites and lamproites) only began in the 1870s after the discovery of diamond fields in South Africa. Production has increased over time and a total of 4.5 billion carats have been mined since then. [] Approximately 20% of this amount was mined in the last 5 years alone and in the last 10 years 9 new mines have started production with another 4 due to open soon. Most of these mines are located in Canada, Zimbabwe, Angola and one in Russia.[]

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In the United States, diamonds have been found in Arkansas, Colorado, and Montana.[][68] In 2004, a surprise discovery of a microscopic diamond in the United States[69] led to a January 2008 bulk sampling of kimberlite tubes in a remote Part of Montana.[70] Today, most economically viable diamond deposits are in Russia, Botswana, Australia and the Democratic Republic of the Congo.[71] In 2005, Russia produced almost a fifth of the world's diamond production, reports the British Geological Survey. Australia has the most prolific diamond pipeline with production of 42 tonnes (41 long tons; 46 short tons) per year in the 1990s (B. Mir Pipeline and Udachnaya Pipeline), Brazil and Northern and Western Australia.

Applications Carbon is essential to all known living systems and without it life as we know it could not exist (see alternative biochemistry). Besides food and wood, carbon is mainly used in the form of hydrocarbons, mainly methane gas as a fossil fuel and crude oil (petroleum). Crude oil is used by the petrochemical industry to produce gasoline and kerosene, among other things, through a distillation process in refineries. Cellulose is a naturally occurring carbonaceous polymer produced by plants in the form of cotton, flax and hemp. Cellulose is mainly used to maintain the structure of plants. Commercially valuable carbon polymers of animal origin include wool, cashmere and silk. Plastics are made from synthetic carbon polymers, often with oxygen and nitrogen atoms contained at regular intervals in the main polymer chain. The raw materials for many of these synthetic substances come from petroleum.

Mechanical pencil leads are made of graphite (often mixed with clay or a synthetic binder).

The use of carbon and its compounds is very diverse. It can form alloys with iron, the most common of which is carbon steel. Graphite combines with alumina to form "lead" which is used in pencils used for writing and drawing. It is also used as a lubricant and pigment, as a molding material in glass manufacture, in electrodes for dry batteries and in electroplating and electroforming, in brushes for electric motors, and as a neutron moderator in nuclear reactors. Charcoal is used as a drawing material in artwork, for grilling, and for many other uses including cast iron. Wood, coal and oil are used as fuels for power generation and space heating. Gem-quality diamonds are used in jewelry, and industrial diamonds are used in drilling, cutting, and polishing tools for working metals and stones. Plastics are made from fossil hydrocarbons, and carbon fibers, produced by the pyrolysis of synthetic polyester fibers, are used to reinforce plastics and form advanced lightweight composites. Carbon fiber is made from pyrolysis of extruded and drawn filaments of polyacrylonitrile (PAN) and other organic substances. The crystallographic structure and the mechanical properties of the fiber depend on the type of charge

Vines and compressed charcoal.

A fabric made of braided carbon threads.

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materials and further processing. Carbon fibers made from PAN have a structure similar to narrow graphite filaments, but thermal processing can rearrange the structure into a continuous laminated sheet. The result is fibers with a higher tensile strength than steel.[] Carbon black is used as a black pigment in printing inks, oil paints, watercolors, carbon paper, automotive paints, ink and toners for laser printers. Carbon black is also used as a filler in rubber products such as tires and in plastic compounds. Activated carbon is used as an absorbent and adsorbent in filter media in applications as diverse as gas masks, water purification, and kitchen hoods, as well as in medicine to absorb toxins, poisons, or gases from the digestive system. Carbon is used in chemical reduction at high temperatures. Coke is used to reduce iron ore to iron. Steel hardening is achieved by heating finished steel components with carbon powder. Silicon, tungsten, boron and titanium carbides are among the hardest materials known and are used as abrasives in cutting and grinding tools. Carbon composites make up most of the materials used in clothing, such as glass, stone, and metal, along with glass, stone, and metal. B. natural and synthetic fabrics and leather, and almost all interior surfaces in the built environment.

diamonds

Single Crystal Silicon Carbide

Fullerene C60 in kristalliner Form

The diamond industry can be broadly divided into two fundamentally different categories: one that deals with quality diamonds and another that deals with industrial quality diamonds. Although both types of diamonds are widely traded, the two markets operate in radically different ways. There is a large trade in gem quality diamonds. Unlike precious metals such as gold or platinum, diamonds are not traded as commodities: there is a significant margin when selling diamonds and there is not a very active market for diamond resale.

carbide drill

The industrial quality diamond market works very differently than its gem quality counterpart. Industrial diamonds are valued primarily for their hardness and thermal conductivity, rendering many of a diamond's gemological characteristics irrelevant, including clarity and color. This helps explain why 80% of the diamonds mined (equivalent to about 100 million carats or 20 tons per year) unfit for use as gemstones and known as Bort are destined for industrial purposes.[72] In addition to mined diamonds, synthetic diamonds found industrial applications almost immediately after their invention in the 1950s; Another 3 billion carats (600 tons) of synthetic diamonds are produced annually for industrial use. [] The predominant industrial use of diamonds is cutting, drilling, grinding and polishing. Most uses of diamonds in these technologies do not require large diamonds; In fact, despite their small size, most gem-quality diamonds can find industrial uses. Diamonds are embedded in drill bits or saw blades, or ground into powder for grinding and polishing applications.[73] Specialty applications include use in laboratories as containment for high pressure experiments (see diamond anvil cell), heavy duty bearings and limited use in specialty windows. With continued advances in the manufacture of synthetic diamonds, future applications become feasible. The possible use of diamond as a semiconductor, suitable for the construction of microchips, or the use of

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Diamond as a heat sink in electronics.[76]

Precautions Pure carbon has extremely low toxicity to humans and can be safely handled and even ingested in the form of graphite or carbon. It is resistant to dissolution or chemical attack, including in acidic contents of the digestive tract. Consequently, once it enters the tissues of the body, it is likely to remain there indefinitely. Carbon black was probably one of the first pigments used for tattooing, and Ötzi the Iceman has been noted to have had carbon tattoos that survived into his lifetime and 5,200 years after his death.[77] However, inhaling large amounts of coal dust or soot (soot) can be dangerous, irritating lung tissue and causing coalworkers' pneumoconiosis, a congestive lung disease. Likewise, diamond dust used as an abrasive can cause damage if swallowed or inhaled. Carbon microparticles are produced in diesel engine exhaust and can accumulate in the lungs.[78] In these examples, the adverse effects may be due to contamination of the carbon particles, such as with organic chemicals or heavy metals, rather than the carbon itself.

Workers at the Sunray, Texas carbon black plant (photo by John Vachon, 1942)

Carbon in general has low toxicity to almost all life on earth; However, it can still be poisonous to some creatures. For example, carbon nanoparticles are lethal to Drosophila.[79] Carbon can also burn violently and intensely in the presence of high-temperature air, as in the Windscale fire caused by the sudden release of Wigner energy stored in the graphite core. Large accumulations of coal that have remained inert without oxygen for hundreds of millions of years can spontaneously ignite when exposed to air, for example in coal mine deposits. The numerous carbon compounds include deadly toxins such as tetrodotoxin, the ricin lectin from the seeds of the castor bean plant Ricinus communis, cyanide (CN−) and carbon monoxide; and vital elements such as glucose and proteins.

CHCl carbon bond

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CNa CMg

California

CSI

ccl auto

CCa CSc CTi

CRb

rsc

CCs CBa Fr

Royal Academy of Fine Arts

CCr CMn CFe

CCo

CNi

CCu CZn CGa Cge CaS

CZr CNb CMo CTc

CRu

CRh

CPd CAg CCd CIn

CHf CTa-Rf

Database

CRE

CIr

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Monte

CSn CSb

CAu CHg CTl CPb Rg

Not

Florida

CBi

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CPo KAT

above

CNd CPm CSm CEu

CTh CPa

CGd CTb CDy CHO CEr CTm CYb CLu

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See.

Maryland

basic organic chemistry

Many uses in chemistry.

Academic research but not widespread use

unknown connection

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Carbon |+ Chemical bonds to carbon

References [7] Magnetic Susceptibility of Inorganic Elements and Compounds (http://www-d0.fnal.gov/hardware/cal/lvps_info/engineering/elementmagn.pdf), in Handbook of Chemistry and Physics, 81st Edition, CRC Press. [8] Properties of diamonds (http://www.ioffe.ru/SVA/NSM/ Semicond/Diamond), database of the Ioffe Institute [23] "Wonderfuel: Welcome to the era of unconventional gas" (http://www .newscientist .com/article/mg20627641.100-wonderfuel-welcome-to-the-age-of-unconventional-gas.html?full=true) by Helen Knight, New Scientist, 12 June 2010, p. [24] "Exaggerated" ocean methane stocks (http://news.bbc.co.uk/2/hi/science/nature/3493349.stm), BBC, 17 Feb 2004. [25] "Ice on fire: The next fossil fuel” (http://www.newscientist.com/article/mg20227141.100) by Fred Pearce, New Scientist, June 27, 2009, pp. 30-33. [26] Calculated from the global.1751_2008.csv file at (http://cdiac.ornl.gov/ftp/ndp030/CSV-FILES) of the Carbon Dioxide Information Analysis Center. [29] Formation of Carbon-14 (http://www.acad.carleton.edu/curricular/BIOL/classes/bio302/pages/carbondatingback.html) [54] Shorter Oxford English Dictionary, Oxford University Press [63] USGS Annual Minerals: Graphite, 2009 (http://minerals.usgs.gov/minerals/pubs/commodity/graphite) and Graphite: Mineral Commodity Summaries 2011 [65] page 159 Debate on alluvial diamonds in India and elsewhere and ancient discoveries [66] Ball was a British service geologist. Chapter I, page 1 [72] Internet Archive (http://www.archive.org/details/turningmechanica02holtuoft) [79] Carbon nanoparticles toxic to adult fruit flies but harmless to juveniles (http://www.sciencedaily.com /releases/2009/08/090807103921.htm) ScienceDaily (08/17/2009)

External links • Carbon (http://www.bbc.co.uk/programmes/p003c1cj) in In Our Time on the BBC. (Listen now (http://www.bbc.co.uk/iplayer/console/p003c1cj/In_Our_Time_Carbon)) • Carbon (http://www.periodicvideos.com/videos/006.htm) in the Periodic Table of Videos (University Nottingham) • Carbon on Britannica (http://www.britannica.com/eb/article-80956/carbon-group-element) • Extensive carbon page on asu.edu (http://invsee.asu.edu/nmodules/Carbonmod /everywhere.html) • Electrochemical Use of Carbon (http://electrochem.cwru.edu/ed/encycl/art-c01-carbon.htm) • Carbon – Super Stuff. Animation with sound and interactive 3D models. (http://www.forskning.no/Artikler/2006/juni/1149432180.36)

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The steel cable of a winding tower

Iron and carbon alloy phases •

Hell •

Ferrite allotropes include: α-iron (alpha ferrite) δ-iron (delta ferrite) β-iron (beta ferrite) ε-iron (hexaferrum) γ-iron (gamma ferrite)

• • • • •

Austenite (γ-iron + carbon in solid solution) Cementite (iron carbide, Fe3C) Graphite (carbon allotrope) Martensite (metastable phase) ε-Carbon (transition carbide, FeC) 24

Microstructures • • • • •

Spheroidite Pearlite (88% ferrite, 12% cementite) Bainite Ledeburite (eutectic austenite-cementite, 4.3% carbon) Hardened martensite (martensite + ferrite + ε-carbon or cementite or both) Steel grades

•

steel crucible

•

Carbon steel (≤ 2.1% carbon; low alloy)

•

spring steel (low-alloy or unalloyed)

•

Alloy steel (contains non-carbon elements)

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Martensitic steel (contains nickel)

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Stainless steel (contains ≥ 10.5% chromium)

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weather-resistant steel

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Tool steel (alloy tool steel) Other iron-based materials

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Cast iron (> 2.1% carbon)

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ductile iron

•

gray iron

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malleable iron

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white iron

•

Wrought Iron (contains Slag)

(Video) Brazing & Soldering

Steel is an alloy of iron and other elements including carbon. When carbon is the main alloying element, its content in steel varies between 0.002 and 2.1% by weight. The following elements are always present in steel: carbon, manganese, phosphorus, sulphur, silicon and traces of oxygen, nitrogen and aluminium. Alloying elements that are intentionally added to modify the properties of steel include: manganese, nickel, chromium, molybdenum, boron, titanium, vanadium and niobium. passed each other. Varying the amount of alloying elements and the form of their presence in the steel (solute elements, precipitated phase) controls properties such as hardness, ductility and tensile strength of the resulting steel. Higher carbon steel can be harder and stronger than iron, but this steel is also less ductile than iron. Alloys with a carbon content of more than 2.1% (depending on the content of other elements and possible processing) are referred to as cast iron. Since they are not deformable even when hot, they can only be worked by casting, they have a lower melting point and good castability. [ ] Steel also differs from wrought iron, which may contain a small amount of carbon. Although steel has been made in a forge for thousands of years, its use spread after more efficient production methods were developed in the 17th century. With the invention of the Bessemer process in the middle of the 19th century, steel became an inexpensive mass-produced material. Other process improvements such as B. the production of basic oxygen steel (BOS), reduced production costs and improved metal quality. Today, steel is one of the most used materials in the world, with over 1.3 billion tons produced annually. It is an important component in buildings, infrastructure, tools, ships, cars, machines, household appliances and weapons. Modern steel is generally identified by different grades defined by a variety of standards organizations.

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Material Properties Iron is only found in the earth's crust in the form of one mineral, mostly as iron oxide such as magnetite, hematite etc. Iron is obtained from iron ore by removing oxygen and combining the ore with a preferred chemical partner such as coal. This process, known as smelting, was first applied to metals with lower melting points, such as tin, which melts at around 250 °C (482 °F), and copper, which melts at around 1,100 °C (2010 °F). For comparison, cast iron melts at about 1375 °C (2507 °F).[] In ancient times, small amounts of solid-state iron were melted by heating buried ore over a coal fire and welding the metal together with a hammer, breaking the iron Compresses the carbon phase diagram and shows the conditions required to form different phases. impurities. With care, the carbon content can be controlled by agitating it in the fire. All of these temperatures could be achieved using ancient methods used since the Bronze Age. Because the oxidation rate of iron increases rapidly above 800°C (1470°F), it is important that smelting take place in an oxygen-poor environment. Unlike copper and tin, liquid or solid iron dissolves carbon quite easily. Casting produces an alloy (pig iron) that contains too much carbon to be called steel. [ ] Excess carbon and other impurities are removed in a later step. Other materials are often added to the mixture of iron and carbon to produce steel with the desired properties. Nickel and manganese in steel increase its tensile strength and make the austenitic form of iron and carbon solution more stable, chromium increases hardness and melting temperature, and vanadium also increases strength, hardness and reduces the effects of metal fatigue.[] To prevent corrosion. , at least 11% chromium is added to the steel so that a hard oxide is formed on the surface of the metal; This is referred to as stainless steel. Tungsten interferes with cementite formation, allowing martensite to form preferentially at slower cooling rates, resulting in high speed steel. On the other hand, sulphur, nitrogen and phosphorus make steel more brittle, so these common elements must be removed from the ore during processing. [ ] The density of steel varies depending on the alloying ingredient, but is generally between 7750 and 8050 kg. /m3 (484 and 503 lb/cu ft) or 7.75 and 8.05 g/cm3 (4.48 and 4.65 oz/cuin).[1] Even in the narrow range of concentrations that make up steel, mixtures of carbon and iron can form many different structures with vastly different properties. Understanding these properties is essential for producing quality steel. At room temperature, body-centered cubic α-ferrite (BCC) is the most stable form of iron. It is a relatively soft metal that can only dissolve a small concentration of carbon, no more than 0.021% by weight at 1333°F (723°C) and only 0.005% at 32°F (0°C). When the steel contains more than 0.021% carbon at steelmaking temperatures, it transforms to a face centered cubic (FCC) structure called austenite or gamma iron. It is also soft and metallic, but can dissolve significantly more carbon, up to 2.1%[2] carbon at 1148°C (2098°F), reflecting the higher carbon content of steel.[3]

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254 When steels with less than 0.8% carbon, known as hypoeutectoid steels, are cooled, the austenitic phase of the mixture attempts to revert to the ferrite phase, resulting in excess carbon. One way for carbon to leave austenite is by precipitating out of solution as cementite, leaving iron with a low enough carbon content to take the form of ferrite, resulting in a ferrite matrix with cementite inclusions. Cementite is a hard, brittle intermetallic compound with the chemical formula Fe3C. In the eutectoid, 0.8% carbon, the cooled structure takes the form of pearlite, so named for its resemblance to nacre. For steels with more than 0.8% carbon, the hardened structure takes the form of pearlite and cementite.[4] Perhaps the most important polymorph of steel is martensite, a metastable phase that is significantly stronger than other steel phases. When steel is in an austenitic phase and then cools rapidly, it becomes martensite as the atoms 'freeze' in place as the cell structure changes from FCC to BCC. Depending on the carbon content, the martensitic phase takes on different forms. Below about 0.2% carbon it adopts a BCC crystal form of α-ferrite, but at higher carbon content it adopts a body centered tetragonal (BCT) structure. There is no thermal activation energy for transforming austenite to martensite. Also, the composition does not change, so atoms generally keep their neighbors the same.[5] Martensite has a lower density than austenite, so the transformation between them creates a change in volume. In this case, expansion occurs. The internal stresses from this expansion generally take the form of compression in the martensite crystals and stresses in the remaining ferrite, with a significant amount of shear in both components. In the case of improper temperature control, internal stresses during cooling can lead to a part breaking. At the very least, they cause internal hardening and other microscopic imperfections. It is common for temper cracks to form when steel is water quenched, although these are not always visible.[6]

Heat Treatment There are many types of heat treatment processes for steel. The most common are annealing, quenching and tempering. Annealing is the process of heating steel to a high enough temperature to soften it. This process occurs in three phases: recovery, recrystallization and grain growth. The temperature required to temper steel depends on the tempering method and the alloy components.[7] During quenching and tempering, the steel is first heated to the austenite phase and then cooled in water or oil. This rapid cooling results in a hard, brittle martensite structure.[5] The steel is then tempered, which is just a special type of anneal. In this application, the annealing (tempering) process converts some of the martensite to cementite or spheroid to reduce internal stresses and defects, resulting in a more ductile and fracture-resistant metal.[8]

steel production

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255 When iron is smelted from its ore by commercial processes, it contains more carbon than is desirable. In order to become steel, it must be melted down and reprocessed to reduce the carbon to the right amount, at which point other elements can be added. This liquid is then continuously poured into long slabs or cast into ingots. Approximately 96% of steel is continuously cast while only 4% is produced as ingots.[9] The ingots are then heated in a dip pit and hot rolled into slabs, billets or billets. The plates are hot or cold rolled into sheet or sheet metal. Billets are hot pellets or iron ore used to make steel. Bars, rebars and cold rolled wires. Blocks are hot or cold rolled from structural steel such as I-beams and rails. In modern steel mills, these processes usually take place on assembly lines, with the ore entering and the finished steel exiting.[10] Sometimes, after a steel has been finished rolling, it is heat treated to increase its strength, but this is relatively rare.[11]

History of Steelmaking Ancient Steel Steel was known in ancient times and may have been made by foundries or iron smelters where the grain contained carbon.[12] The oldest known steel production is a piece of iron unearthed at an archaeological site in Anatolia (Kaman-Kalehoyuk) and is around 4,000 years old.[13] Another ancient steel comes from East Africa and dates back to 1400 BC. C. [14] In the 4th century B.C. C., Steel weapons such as the falcata were manufactured in the Iberian Peninsula, while the Roman army used Norse steel.[15] Steel was made in Sparta around 650 BC. produced in large quantities. c.[16][17] The Chinese of the Warring States (403–221 BC) had hardened steel,[18] while the Chinese of the Han Dynasty (202 BC–220 AD) made steel by fusing wrought iron with cast iron and a final product of an intermediate obtained carbon steel in the 1st century AD[][19] The Haya of East Africa invented a type of furnace almost 2000 years ago, which they used to produce carbon steel at 1802 °C (3276 °F).[20 ]

Flower Foundry in the Middle Ages.

Wootz Steel and Damascus Steel Evidence of the first production of carbon steel in the Indian subcontinent was found in the Samanalawewa area of Sri Lanka.[21] Wootz steel was made around 300 BC. Manufactured in India. C. [22] However, steel was an old technology.

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256 in India, when King Porus 326 BC. BC Emperor Alexander presented a steel sword. Apparently, steel technology existed before 326 BC. C., since steel was then exported to the Arab world. Since the technology was acquired by the Tamils of southern India, the origin of steel technology in India can be conservatively dated to 400-500 BC. be estimated. In addition to their original methods of forging steel, the Chinese also adopted production methods to create wootz steel, an idea imported to China from India in the 5th century AD.[23] In Sri Lanka, this early method of steelmaking used a unique wind furnace powered by monsoon winds, capable of producing high-carbon steel. It was originally made from several different materials, including various trace elements. It was essentially an intricate alloy with iron as the main ingredient. Recent studies suggest that carbon nanotubes were included in its structure, which could explain some of its legendary properties, although these occurred more accidentally than intended given the technology available at the time.[24] Natural wind was used where ferrous soil was heated through the use of wood. The ancient Sinhalese managed to extract one ton of steel for every 2 tons of earth, [] a remarkable feat at the time. Such a furnace was found at Samanalawewa, and archaeologists were able to make steel as the ancients did. made at Merv between the 9th and 10th centuries AD [22] In the 11th century there is evidence of steelmaking in Song China using two techniques: a "Berganesque" method which produced inferior, inhomogeneous steel, and a Forerunner of the modern Bessemer process, which used partial decarburization by repeated forging. Air. .[26]

Modern Steelmaking Since the 17th century, the first step in steelmaking in Europe was the smelting of iron ore into pig iron in a blast furnace.[27] Originally using charcoal, modern methods use coke, which has proven to be more economical.[28][29][30] Bar iron process In this process, pig iron was "refined" in a fine forge into iron bars (wrought iron), which were then used to produce steel.[27] The manufacture of steel by the cementing process was described in a treatise published in Prague in 1574 and had been in use in Nuremberg since 1601. A similar process for cementing armor and files, described in a book published in Naples in 1589, was introduced to England around 1614 and used in the 1610s by Sir Basil Brooke of Coalbrookdale to make such steel.[31] The raw material for this process was wrought iron bars. In the 17th century it was discovered that the best steel came from iron deposits in a region north of Stockholm, Sweden. This continued to be the usual source of raw materials well into the 19th century, almost as long as the process was in use.[32][]

A Bessemer converter in Sheffield, England

Crucible steel is steel that has been melted in a crucible rather than forged, making it more homogeneous. Most early furnaces could not reach temperatures high enough to melt steel. The modern crucible steel industry was the result of Benjamin Huntsman's invention in the 1740s. Blister steel (made as above) was melted in a crucible or furnace and (usually) cast into ingots. [] [33]

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257 Pig Iron Process The modern era of steelmaking began with the introduction of the Bessemer process by Henry Bessemer in 1858, the starting material for which was pig iron.[34] His method enabled him to produce steel in large quantities at a low cost, so that mild steel was used for most of the purposes that wrought iron was once used for.[35] The Gilchrist-Thomas process (or basic Bessemer process) was an improvement on the Bessemer process, in which the converter was coated with a base material to remove phosphorus. Another improvement in steelmaking was the Siemens-Martin process, which complemented the Bessemer process. manufacturing methods. Simple oxygen steelmaking is superior to previous steelmaking methods because the oxygen pumped into the furnace limits contaminants that had previously entered from the spent air.[36] Electric arc furnaces (EAFs) are now a common method of reprocessing scrap into new steel. They can also be used to convert pig iron into steel, but they consume a lot of electricity (about 440 kWh per tonne) and are therefore usually only economical when cheap electricity is plentiful.[37]

A Siemens-Martin steel furnace from the Brandenburg Industrial Museum.

Glowing steel comes out of an electric arc furnace.

Steel Industry It is common nowadays to speak of the “steel industry” as if it were a single entity, but historically they were separate products. The steel industry is often viewed as an indicator of economic progress because of the critical role steel plays in infrastructure and overall economic development.[38] In 1980 there were over 500,000 American steelworkers. In 2000, the number of metallurgists dropped to 224,000.[39]

Steel production by country in 2007

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258 The economic boom in China and India has led to a massive increase in demand for steel in recent years. Between 2000 and 2005, global steel demand increased by 6%. Since 2000, several Indian and Chinese steel companies have risen to prominence, including Tata Steel (which bought Corus Group in 2007), Shanghai Baosteel Group Corporation and Shagang Group. However, ArcelorMittal is the largest steel producer in the world. In 2005, the British Geological Survey stated that China was the top steel producer, accounting for about a third of the world's share; Japan, Russia and the United States followed respectively.[41]

A steel mill in the UK.

Steel has been traded as a commodity on the London Metal Exchange since 2008. In late 2008, the steel industry faced a severe recession that led to many cutbacks.[42] The global steel industry peaked in 2007. That year, ThyssenKrupp spent $12 billion to build the world's two most advanced plants in Calvert, Alabama, and Sepetiba, Rio de Janeiro, Brazil. However, the global Great Recession that began in 2008 drastically reduced demand and new construction, causing prices to fall. ThyssenKrupp lost $11 billion on its two new plants selling steel below production costs. Finally, in 2013, ThyssenKrupp put the plants up for sale for less than $4 billion.[43]

Contemporary Steel Modern steels are made from various combinations of metal alloys for many purposes.[] Carbon steel, being simply iron and carbon, accounts for 90% of steel production.[] Low-alloy, high-strength steel has small additions (generally < 2% by weight) of other elements, typically 1.5 percent manganese, to provide additional strength for a modest price increase.[44] Low-alloy steel is alloyed with other elements, usually molybdenum, manganese, chromium, or nickel, in amounts up to 10% by weight, to improve hardenability of thick sections. of the world's largest steel producers before the closure in 2003 and later surgical stainless steel contain at least 11% conversion in a casino. Chromium often combined with nickel to resist corrosion (rusting). Some stainless steels such as B. ferritic stainless steels are magnetic, while others, such. B. austenitic stainless steels, are not magnetic.[45] Corrosion-resistant steels are abbreviated as CRES. Some newer steels include tool steels alloyed with large amounts of tungsten and cobalt or other elements to maximize solution hardening. This also enables the use of precipitation hardening and improves the temperature resistance of the alloy. [ ] Tool steel is commonly used in axes, drills and other implements that require a durable sharp edge. Other specialty alloys include weather-resistant steels such as Corten, which wear down to a stable, oxidized finish so they can be used without painting.[46]

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259 There are many other high strength alloys such as B. Two-phase steel that is heat treated to obtain a ferritic and martensitic microstructure to increase strength.[47] Transformation Induced Plasticity (TRIP) steel includes special alloys and heat treatments to stabilize the austenite levels at room temperature in low-alloy ferritic steels that are normally austenite-free. By applying stress to the metal, the austenite undergoes a phase transition to martensite without the addition of heat.[48] Maraging steel is alloyed with nickel and other elements, but unlike most steels, contains almost no carbon. This creates a very strong yet malleable metal.[49] Twin Induced Plasticity (TWIP) steel uses a specific type of deformation to increase the effectiveness of work hardening in the alloy.[50] Eglin Steel uses a combination of over a dozen different elements in varying amounts to create a relatively inexpensive metal for use in bunker-busting weapons. Hadfield steel (named after Sir Robert Hadfield) or manganese steel contains 12-14% manganese, which when used forms an incredibly tough skin that resists wear and tear. Examples include tank tracks, bulldozer blade edges, and blades in the jaws of life.[51] Most of the most commonly used steel alloys are divided into different classes by standards organizations. For example, the Society of Automotive Engineers has a number of classes that define many types of steel. [] The American Society for Testing and Materials has a separate set of standards that define alloys such as A36 steel, the most commonly used structural steel in the United States.[52] Although not an alloy, galvanized steel is a commonly used type of steel that has been hot-dipped or zinc-plated to protect it from rusting.[53]

Iron and steel are widely used in the construction of roads, railroads, other infrastructure, household appliances, and buildings. Most large modern structures such as stadiums and skyscrapers, bridges and airports are supported by a steel skeleton. Even those with a concrete structure use steel as reinforcement. In addition, it is widely used in home appliances and automobiles. Despite the increasing use of aluminum, it remains the main body material. Steel is used in a variety of other building materials such as screws, nails, and screws.[54] Other common uses include shipbuilding, pipeline transportation, mining a roll of steel wool, offshore construction, aerospace, home appliances (e.g. washing machines), heavy equipment such as excavators, office furniture, steel wool, tools and armor in the form of personal gear. Vests or vehicle armor (better known as rolled homogeneous armor in this role). Steel was the metal of choice for sculptor Jim Gary and a common choice for sculpture by many other modern sculptors.

Background Before the advent of the Bessemer process and other modern production techniques, steel was expensive and only used where there was no cheaper alternative, particularly for sharpening knives, razors, swords and other items where a hard edge was needed. Sharp. . It was also used for springs, among other things for clocks. [ ] With the advent of faster and cheaper production methods, steel became more readily available and much cheaper. wrought iron replaced.

A carbon steel knife

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260 for a variety of purposes. However, the availability of plastics in the late 20th century allowed these materials to replace steel in some applications due to their lower manufacturing cost and lighter weight.[55] Carbon fiber is replacing steel in some cost-insensitive applications such as airplanes, sports equipment and high-end automobiles.

Long bars • As reinforcing bars and mats in reinforced concrete • Railway tracks • Structural steel in modern buildings and bridges • Wires • Use for reinforcement applications

Carbon Steel Flat Bar • Large Household Appliances • Core Magnets

A steel pole hanging overhead power lines

• The interior and exterior body of cars, trains and ships.

Stainless Steel • Cutlery • Rulers • Surgical Instruments • Watches

Low-bottom steel Steel made after World War II was contaminated with radionuclides due to nuclear weapons testing. Low-bottom steel, steel manufactured before 1945, is used for certain radiation-sensitive applications such as Geiger counters and radiation shielding.

A sauce boat made of stainless steel

References [2] Sources differ on this number, so it has been rounded to 2.1%. The exact value is quite academic, however, as ordinary carbon steel is rarely made with this carbon content. See: • -2.08%. • —2.11%. • —2.14%. [3] . [4] . [5] . [7] . [8th] . [10] . [15] "Noricus ensis", Horace, Odes, i. 16.9 [19] Gernet, 69. [20] The Ancient Steelmakers of Africa (http://www.time.com/time/revista/article/0,9171,912179,00.html?promoid=googlep). Time Magazine, September 25, 1978. [22] Ann Feuerbach, “An Examination of Various Technologies Found in Swords, Sabers, and Blades from the Russian North Caucasus,” IAMS 25, 2005, pp. 27–43 (p. 29) (https://www.es.ucl.ac.uk/iams/jour_25/iams25_Feuerbach.pdf), apparently from the writings of Zosimos of Panopolis. [23] Needham, Volume 4, Part 1, p. 282

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261 [27] Tylecote, R. F. A History of Metallurgy, 2. Aufl., Institute of Materials, Londres 1992, S. 95–99 und 102–105. [28] Raistrick, A. A Dynasty of Ironfounders (1953; York 1989) [29] Hyde, C. K. Technological Change and the British Iron Industry (Princeton 1977) [30] Trinder, B. A Revolução Industrial em Shropshire (Chichester 2000) . ) [31] Barraclough, K. C. Steel vor Bessemer: I Blister Steel: the Birth of an Industry (The Metals Society, London, 1984), S. 48–52. [33] K. C. Barraclough, Steel antes de Bessemer: II Crucible Steel: The Growth of Technology (The Metals Society, Londres, 1984). [37] Jones, J.A.T. ; Bowman, B. und Lefrank, P.A. Fabricação de aço em forno elétrico, in The Making, Shaping and Treating of Steel, S. 525–660. R. J. Fruehan, Herausgeber. 1998, AISE Steel Foundation: Pittsburgh. [39] „Congress Record V. 148, Pt. 4, 11 de abril de 2002 a 24 de abril de 2002 (http://books. google. com/books?id=iOgfSDKecCcC& pg=PA4557& dq& hl=en#“ v= onepage& q=&f=false)“ Escritório de impressão do governanceo dos EUA. [43] John W. Miller und Ike Henning, „Thiessen recebe ofertas para siderúrgicas: ofertas finais para complexos siderúrgicos no Alabama, Brasil provavelmente não atenderão às esperanças da empresa", Wall Street Journal, 1. März 2013 [51] Manganese Steel Hadfield . (http://answers.com/topic/hadfield-manganese-steel) Answers.com. McGraw-Hill Dictionary of Scientific and Technical Terms , McGraw-Hill Companies, Inc., 2003. Konsultiert am 28. Februar 2007. [52] Steel Construction Manual, 8. Ausgabe, spätere überarbeitete Ausgabe, American Institute of Steel Construction, 1986, Kapitel 1, Seiten 1-5

Literature • Ashby, Michael F.; Jones, David Rayner Hunkin (1992). An introduction to microstructures, processing and design. Butterworth-Heinemann. • Bugayev, K.; Konovalov, Y.; Bychkov, Y.; Tretyakov, E.; Savin, Ivan V. (2001). Iron and Steel Production (http://books.google.com/?id=MJdIVtmwuUsC). Minerva Group, Inc. ISBN978-0-89499-109-7. Retrieved July 19, 2009. • Degarmo, E. Paul; Black, JT.; Kohser, Ronald A (2003). Materials and Methods of Manufacture (9th ed.). wiley. ISBN 0-471-65653-4. • Gernet, Jacques (1982). A History of Chinese Civilization. Cambridge: Cambridge University Press. • Smith, William F.; Hashemi, Javad (2006). Foundations of Materials Science and Engineering (4th ed.). McGraw-Hill. ISBN0-07-295358-6.

Leitura additional • Duncan Burn; A história econômica da siderurgia, 1867–1939: um estudo sobre a concorrência (http://questia.com/PM.qst?a=o&d=3914930). Cambridge University Press, 1961. • Harukiyu Hasegawa, The Steel Industry in Japan: A Comparison with Britain (http://questia.com/PM.qst?a=o&d=108742046). 1996. • JC Carr and W Taplin, History of the British Steel Industry (http://questia.com/PM.qst?a=o&d=808791). Harvard University Press, 1962. • H. Lee Scamehorn, Mill & Mine: The Cf&I in the Twentieth Century (http://questia.com/PM.qst?a=o&d=94821694). University of Nebraska Press, 1992. • Needham, Joseph (1986). Science and Civilization in China: Volume 4, Part 1 and Part 3. Taipei: Caves Books, Ltd. • Warren, Kenneth, Big Steel: The First Century of the United States Steel Corporation, 1901–2001 (http://eh.net/bookreviews/library/0558). University of Pittsburgh Press, 2001.

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Externe Links • World Steel Association (worldsteel) (http://www.worldsteel.org/) • steeluniversity.org: Online-Stahlbildungsressourcen von worldsteel und der University of Liverpool (http://steeluniversity.org/) • Great Archive on Steels, University of Cambridge (http://www.msm.cam.ac.uk/phase-trans/2005/Fealloys.html) • Cooking with Steels (http://www.wastedtalent.ca/comic/cooking- Stahl) • Metalworking for Non-Metalworkers von der American Metal Society (http://books.google.com/books?id=brpx-LtdCLYC&pg=PA26&lpg=PA26&d#v=onepage&q&f=true,)

Chemical element

Above: the periodic table of the chemical elements. Bottom: Examples of specific chemical elements. From left to right: hydrogen, barium, copper, uranium, bromine and helium.

A chemical element is a pure chemical substance made up of one type of atom, distinguished by their atomic number, which is the number of protons in their nucleus. Elements are divided into metals, semimetals and nonmetals. Well-known examples of elements are carbon, oxygen (non-metals), silicon, arsenic (semi-metals), aluminum, iron, copper, gold, mercury and lead (metals). The lightest chemical elements, including hydrogen, helium (and smaller amounts of lithium, beryllium, and boron), are believed to have been formed by various cosmic processes during the Big Bang and cosmic ray spallation. The production of heavier elements, from carbon to the heavier elements, proceeded from stellar nucleosynthesis, and these were made available for later formation of solar and planetary systems by planetary nebulae and supernovae, which hurl these elements into space.[1 ] The great abundance of oxygen, silicon and iron on Earth reflects their joint production in these stars after the lighter gaseous elements and their compounds have been stripped away. Although most elements are generally considered stable, a small amount of natural conversion from one element to another occurs today through the decay of radioactive elements and other natural nuclear processes. The history of the discovery and use of elements began with the first human societies finding native elements such as copper and gold and extracting (molten) iron and some other metals from their ores. Many more were later identified by alchemists and chemists, and by 1900 almost all natural elements were known. The properties of chemical elements are often summarized using the periodic table, which organizes elements into series ("periods") by increasing atomic number. the columns ("clusters") sharing recurring ("periodic") physical and chemical properties. With the exception of the short-lived radioactive elements, all elements are industrially available, most of them in high purity. Hydrogen and helium are by far the most abundant elements in the universe. However, iron is the most abundant element (by mass) that makes up the earth, and oxygen is the most abundant element in the earth's crust. [] Although all known chemical matter consists of these elements, it is believed that chemical matter consists only of itself

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Chemical element about 15% of the matter in the universe. The rest is believed to be dark matter, a mysterious substance that is not made up of chemical elements because it lacks protons, neutrons, or electrons.[2] When two or more different elements are combined chemically, with the atoms held together by chemical bonds, the result is called a chemical compound. Two-thirds of the chemical elements occur on Earth only as compounds, and for the remaining third, compound forms of the element are often the most common. [citation needed] Chemical compounds can be composed of elements combined in precise proportions of whole atomic numbers, as in water, common salt, and minerals such as quartz, calcite, and some minerals. However, the chemical bonding of many types of elements results in crystalline solids and metallic alloys for which precise chemical formulas do not exist. Relatively pure samples of isolated elements are rare in nature. Although all 98 natural elements have been identified in mineral samples from the earth's crust, only a small minority of the elements are found as relatively pure and recognizable minerals. The most common of these "native elements" include copper, silver, gold, carbon (such as coal, graphite, or diamonds), sulfur, and mercury. Almost all less reactive elements such as noble gases and noble metals generally occur on earth in chemically bound form as chemical compounds. Although about 32 of the chemical elements on earth occur in native, uncombined forms, most of them occur as mixtures. For example, atmospheric air is primarily a mixture of nitrogen, oxygen, and argon, and the natural solid elements are found in alloys such as iron and nickel. As of November 2011, 118 elements have been identified, the last being Ununseptium in 2010. [] Of the 118 known elements, only the first 98 are known to occur naturally on Earth; 80 of them are stable, while the rest are radioactive and decay into lighter elements over various timescales from fractions of a second to billions of years. These elements, which do not occur naturally on Earth, have been man-made as synthetic products of man-made nuclear reactions.

Description The lightest chemical elements are hydrogen and helium, both produced by the Big Bang nucleosynthesis during the first 20 minutes of the universe[3] in a ratio of about 3:1 by mass (roughly 12:1 by number of atoms). [4][5] Almost all other naturally occurring elements, including some of the hydrogen and helium produced since then, have been produced by various natural or (sometimes) artificial methods of nucleosynthesis.[6] On Earth, a small number of new atoms are created naturally in nucleogenic reactions or in cosmogenic processes such as cosmic ray spallation. New atoms also occur naturally on Earth as radiogenic isotopes, children of ongoing radioactive decay processes such as alpha decay, beta decay, spontaneous fission, cluster decay, and other rarer types of decay. Of the 98 natural elements, those with atomic numbers from 1 to 40 are considered stable. Elements atomic number 41 through 82 are apparently stable (except technetium, element 43, and promethium, element 61, which are unstable), but are theoretically unstable and therefore possibly slightly radioactive. However, the half-lives of elements 41 to 82 are so long that their radioactive decay cannot be demonstrated in experiments. These "theoretical radionuclides" have half-lives at least 100 million times longer than the estimated age of the universe. Elements with atomic numbers from 83 to 98 are so unstable that their radioactive decay can be detected. Some of these elements, most notably thorium (atomic number 90) and uranium (atomic number 92), have one or more isotopes with half-lives long enough to survive as remnants of the explosive stellar nucleosynthesis that produced the heavy elements before formation our solar system. For example, bismuth-209 (atomic number 83) has the longest known alpha-decay half-life of any element at over 1.9 × 1019 years, more than billion times the current estimated age of the universe. of course.[][] The heaviest elements (other than californium, atomic number 98) decay radioactively with half-lives so short that they do not occur naturally and must be synthesized. As of 2010, there are 118 known elements (in this context, "known" means observed well enough, even by some decay products, to be distinguished from every other element). [9][] Of these 118 elements, 98 occur naturally on Earth.[10] Ten of these occur in trace amounts: technetium, atomic number 43; Prometheus,

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chemical element number 61; status, number 85; francium, number 87; Neptunium, number 93; plutonium, number 94; Americium, number 95; curiosity, number 96; Berkelium, number 97; and Californium, number 98. These 98 elements have been found throughout the universe, in the spectra of stars and also in supernovae, where short-lived radioactive elements form. The first 98 elements were detected directly on Earth as primordial nuclides from the formation of the solar system or as natural fission or transformation products of uranium and thorium. The remaining 24 heaviest elements, found neither on Earth nor in astronomical spectra today, were derived artificially. All heavy elements that are exclusively man-made are radioactive and have very short half-lives; If any atoms of these elements were present when the Earth was formed, it is very likely that they were already decayed, and if present in novae, they were present in too small quantities to be noticed. Technetium was the first supposedly unnatural element to be synthesized in 1937, although traces of technetium have been found in nature since then (and it's also possible that the element was discovered naturally in 1925).[11] This pattern of artificial production and subsequent natural discovery has been repeated with several other naturally occurring rare radioactive elements.[12] Lists of elements are available by name, symbol, atomic number, density, melting point and boiling point, and by element ionization energies. Nuclides of stable and radioactive elements are also available as a list of nuclides sorted by half-life for the unstable ones. One of the most convenient, and certainly most traditional, representations of elements is the periodic table, which groups together elements with similar chemical properties (and usually similar electronic structures as well).

Atomic Number The atomic number of an element is equal to the number of protons that define the element.[13] For example, all carbon atoms contain 6 protons in their nucleus; the atomic number of carbon is therefore 6.[14] Carbon atoms can have different numbers of neutrons; Atoms of the same element that have different numbers of neutrons are called the isotopes of the element.[15] The number of protons in the nucleus also determines its electrical charge, which in turn determines the number of electrons in the atom in the unionized state. Electrons are placed in atomic orbitals that determine the various chemical properties of the atom. The number of neutrons in a nucleus generally has very little effect on the chemical properties of an element (except in the case of hydrogen and deuterium). Therefore, all carbon isotopes have almost identical chemical properties as they all have six protons and six electrons, although carbon atoms can differ in the number of neutrons. For this reason, atomic number and not mass number or atomic weight is considered the identifying characteristic of a chemical element. The atomic number symbol is Z.

Atomic Mass and Atomic Weight The mass number of an element, A, is the number of nucleons (protons and neutrons) in the nucleus of an atom. The different isotopes of a given element are distinguished by their mass numbers, which are usually written in superscript to the left of the atomic symbol (e.g. 238U). The mass number is always a simple integer and has units of "nuclei". An example of a reference to a mass number is "mg-24", which is an atom with 24 nuclei (12 protons and 12 neutrons). While the mass number simply counts the total number of neutrons and protons and is therefore a natural (or integer) number, the atomic mass of a single atom is a real number for the mass of a particular isotope of the element. , the unit is you . When expressed as u, it generally differs slightly in value from the mass number of a given nuclide (or isotope), since the mass of protons and neutrons is not exactly 1 u, since electrons contribute less to atomic mass than the number of u .Neutrons exceed the number of protons and is (ultimately) due to nuclear binding energy. For example, the atomic weight of chlorine-35 is 34.969 u to five significant digits and that of chlorine-37 is 36.966 u.

265

However, the atomic mass in u of atoms of pure isotopes is very close to their simple mass number (always within 1%). The only exception to the atomic mass of an isotopic atom that is not a natural number is 12C, which by definition has a mass exactly 12 because u is defined as 1/12 the mass of a neutral carbon-12 atom. the ground state. The relative atomic mass (historically and also commonly referred to as "atomic weight") of an element is the average of the atomic masses of all isotopes of the chemical element found in a given environment, weighted by isotopic abundance, relative to the atomic mass unit ( Sie). This number may be a fraction, not close to a whole number, due to the averaging process. For example, the relative atomic mass of chlorine is 35.453 u, which is very different from an integer since it is composed, on average, of 76% chlorine-35 and 24% chlorine-37. Whenever a relative atomic mass value deviates from an integer by more than 1%, it is due to this averaging effect resulting from significant amounts of more than one naturally occurring isotope in the sample of that element.

Isotopes Isotopes are atoms of the same element (that is, with the same number of protons in the nucleus), but with a different number of neutrons. Most natural elements (66 out of 94) have more than one stable isotope. For example, there are three main isotopes of carbon. All carbon atoms have 6 protons in their nucleus but can have 6, 7, or 8 neutrons. Because their mass numbers are 12, 13, and 14, respectively, the three carbon isotopes are known as carbon-12, carbon-13, and carbon-14, often abbreviated as 12C, 13C, and 14C. Carbon in everyday life and in chemistry is a mixture of 12C, 13C and (a very small fraction) 14C atoms. With the exception of hydrogen isotopes (which differ widely in relative mass, enough to cause chemical effects), isotopes of a given element are almost indistinguishable chemically. All elements have some isotopes that are radioactive (radioisotopes), although not all of these radioisotopes occur naturally. Radioisotopes usually decay into other elements by emitting an alpha or beta particle. When an element has isotopes that are not radioactive, they are called "stable" isotopes. All known stable isotopes occur naturally (see primordial isotope). The many non-naturally occurring radioisotopes have been characterized after their artificial generation. Certain elements have no stable isotopes and consist only of radioactive isotopes: elements without stable isotopes are notably technetium (atomic number 43), promethium (atomic number 61) and all observed elements with atomic numbers greater than 82 of the 80 elements with at least one stable isotope, 26 only one stable isotope. The average number of stable isotopes for the 80 stable elements is 3.1 stable isotopes per element. The largest number of stable isotopes found for a single element is 10 (for tin, element 50).

Allotropes of atoms of pure elements can be chemically bound in more than one way, allowing the pure element to exist in multiple structures (spatial arrangements of atoms) known as allotropes, which differ in their properties. For example, carbon can be found in the form of a diamond, which has a tetrahedral structure around each carbon atom; graphite having layers of stacked hexagonal carbon atoms; graphene, which is a single layer of very tough graphite; fullerenes, which are nearly spherical; and carbon nanotubes, which are tubes having a hexagonal structure (even these may differ in electrical properties). The ability of an element to exist in one of many structural forms is called "allotropy". The standard state, also called reference state, of an element is defined as its most thermodynamically stable state at 1 bar at a given temperature (typically 298.15 K). In thermochemistry, an element is defined as having zero enthalpy of formation in its standard state. For example, graphite is the reference state for carbon because graphite's structure is more stable than other allotropes.

266

Chemical element

Properties Various types of descriptive categorization can be applied to elements in general, including consideration of their general physical and chemical properties, their states of matter under familiar conditions, their melting and boiling points, their densities, their crystalline structures as solids, and their origin. . . General Properties Several terms are commonly used to characterize the general physical and chemical properties of chemical elements. A first distinction is made between metals, which readily conduct electricity, nonmetals, which do not, and a small group (the metalloids) which have intermediate properties and often behave like semiconductors. A more refined classification is usually shown in color representations of the periodic table. This system limits the terms "metal" and "nonmetal" to just a few of the broader metals and nonmetals and adds additional terms for specific groups of metals and nonmetals that are considered more broadly. The version of this classification used in the periodic tables presented here includes: actinides, alkali metals, alkaline earth metals, halogens, lanthanides, post-transition metals (or "other metals"); Semi-metals, noble gases, non-metals (or "other non-metals"); and transition metals. In this system, special metal groups in the broader sense are the alkali metals, alkaline earth metals and transition metals as well as the lanthanides and actinides. Likewise, halogens and noble gases are nonmetals in the broadest sense. In some presentations, the halogens are indistinguishable, with astatine identified as a semimetal and others as nonmetals. Physical States Another commonly used basic distinction between elements is their physical state (phase), whether solid, liquid, or gas, at a selected standard temperature and pressure (STP). Most elements are solid at standard atmospheric temperature and pressure, while many are gases. Only bromine and mercury are liquid at 0 degrees Celsius (32 degrees Fahrenheit) and normal atmospheric pressure; Cesium and gallium are solid at this temperature but melt at 28.4 °C (83.2 °F) and 29.8 °C (85.6 °F) respectively. Melting and Boiling Points Melting and boiling points, typically expressed in degrees Celsius at one atmosphere of pressure, are commonly used to characterize the various elements. Although known for most elements, for some of the radioactive elements present only in trace amounts, one or both measurements have yet to be determined. Because helium remains a liquid at atmospheric pressure, even at absolute zero, it only has a boiling point and no melting point in conventional forms. Densities Density at a selected standard temperature and pressure (STP) is often used to characterize elements. Density is usually expressed in grams per cubic centimeter (g/cm3). Because many elements are gases at commonly encountered temperatures, their densities are generally given for their gaseous forms; When liquefied or solidified, gaseous elements have densities similar to other elements. When an element has allotropes of different densities, a representative allotrope is usually selected in the summary presentations, while the densities of each allotrope can be given where further details are provided. For example, the three known allotropes of carbon (amorphous carbon, graphite, and diamond) have densities of 1.8-2.1, 2.267, and 3.515 g/cm3, respectively.

267

Chemical element

268

Crystal Structures The elements studied so far as solid samples have eight types of crystal structures: cubic, body-centered cubic, face-centered cubic, hexagonal, monoclinic, orthorhombic, rhombohedral, and tetragonal. For some of the synthetically produced transuranic elements, the available samples were too small to determine crystalline structures. Occurrence and Origin on Earth Chemical elements can also be categorized according to their terrestrial origin, with the first 98 considered natural, while those with atomic numbers above 98 are man-made as synthetic products of man-made nuclear reactions. Of the 98 natural elements, 84 are considered pristine and stable or metastable (apparently stable but theoretically unstable or radioactive). The remaining 14 natural elements have half-lives too short to be present in the early solar system and are therefore considered transient elements. Of these 14 transient elements, 7 (polonium, astatine, radon, francium, radium, actinium, and protactinium) are relatively common decay products of thorium, uranium, and plutonium. The remaining 7 transient elements (technetium, promethium, neptunium, americium, curium, berkelium, and californium) are rare because they are products of rare nuclear reaction processes involving uranium or other heavy elements. Elements with atomic numbers 1 through 40 are all stable, while elements with atomic numbers 41 through 82 (except technetium and promethium) are metastable. The half-lives of these metastable “theoretical radionuclides” are so long (at least 100 million times longer than the estimated age of the Universe) that their radioactive decay has yet to be verified experimentally. Elements with atomic numbers from 83 to 98 are so unstable that their radioactive decay can be detected. Some of these elements, most notably thorium (atomic number 90) and uranium (atomic number 92), have one or more isotopes with half-lives long enough to survive as remnants of the explosive stellar nucleosynthesis that produced the heavy elements before formation our solar system. For example, bismuth-209 (atomic number 83) has the longest known alpha-decay half-life of any element at over 1.9 × 1019 years, more than billion times the current estimated age of the universe. of course.[][] The heaviest elements (other than californium, atomic number 98) decay radioactively with half-lives so short that they do not occur naturally and must be synthesized.

The periodic table Periodic table 4

fifteen

The pnictogen

cha

Boro

Money

nitrogen

Norte

Aluminium

silicon

Phosphor

fifteen

Alabama

PAG

Metro

Chemical element

269

Titan

Vanadium

Chrom

Mangan

Eisen

Cobalt

Nickel

copper

Zink

Gallium

Deutschland

Arsenic

Von

Minnesota

trust

company

copper

Zink

Georgia

Zirconium

niobium

Palladium

Talk

Cadmium

Indonesian

Lata

antimony

Mes

Agriculture

nice

We stayed

Tantalus

Wolfram

guide

eight

irídio

platinum

Gold

mercury

Cut

Lead

bismuth

H.f.

For

Eras

point it out

Rutherfordio

I do not know

seeborgio

bohrio

104

105

106

107

108

109

110

111

112

113

114

115

Radiofrequenz

Database

Monte

Not

Florida

above

Cer

Molybdenum Technetium Ruthenium Rhodium

Praseodymium Neodymium Promethium Samaritan Europeans

Gadolinium

Terbio

Dysprosium

holmio

coelho

we're still

Sixty-five

public relation

Dakota do Norte

little bit

Di-s

Tuberculosis

to die

Thorium

Protactinium

Career

cut

Berkelio

fermio

Mendelejew

100

101

Pennsylvania

Public notary

Military

Negro

See.

Maryland

America's Plutonium Neptune

California Einstenio

Physical state (at 0 °C and 1 atm): black = solid green = liquid red = gaseous gray = unknown

Das Element: Primordial Decay Synthetic

Metalloid

Inner transition metal Transition metal Thin metal

PAG

Hassium Meitnerium Darmstadtium Roentgenium Copernicium Ununtrium Flerovium Ununpentium Li

Metal

i was metal

Unknown Chemical Substance Polyatomic Nonmetal Diatomic nonmetallic properties of noble gases

Actins Antans

The properties of chemical elements are often summarized using the periodic table, which organizes elements powerfully and elegantly by increasing atomic number in rows ("periods") where columns ("groups") share physical and recurring properties ("periods") . chemical properties. The current standard table contains 118 items confirmed on April 10, 2010. Although precursors existed before this presentation, their invention is generally credited to the Russian chemist Dmitri Mendeleev in 1869, who intended the table to illustrate recurring trends in the properties of objects. . The layout of the table has been refined and expanded over time as new elements were discovered and new theoretical models to explain chemical behavior were developed. The use of the periodic table is now ubiquitous in the academic discipline of chemistry and provides an extremely useful framework for classifying, systematizing, and comparing all different forms of chemical behavior. The table has also found wide applications in physics, geology, biology, materials science, engineering, agriculture, medicine, nutrition, environmental health, and astronomy. Its principles are particularly important in chemical engineering.

Norte

Chemical element

Nomenclature and Symbols The various chemical elements are formally identified by their unique atomic numbers, their accepted names, and their symbols.

Atomic numbers Well-known elements have atomic numbers from 1 to 118, which are conventionally represented as Arabic numerals. Since elements can be ordered unambiguously by atomic number, usually from smallest to largest (as in a periodic table), sets of elements are sometimes indicated by notations such as "to", "beyond", or "from...to". , as in "through iron", "beyond uranium", or "from lanthanum to lutetium". The terms "light" and "heavy" are also sometimes used informally to indicate relative atomic numbers (not densities!), as in "lighter than carbon" or "heavier than lead", although technically the weight or mass of an element's atoms (its atomic weights or atomic masses) do not always increase monotonically with its atomic numbers.

Naming Elements The naming of various substances known today as elements predates the atomic theory of matter, as different cultures gave local names to various minerals, metals, compounds, alloys, mixtures, and other materials even though these were not known at the time. you knew. which chemicals were elements and which were compounds. Because they are identified as elements, the names for elements (e.g., gold, mercury, iron) known in ancient times have been retained in most countries. National differences arose over the names of the elements, whether due to convenience, linguistic subtleties, or nationalism. To illustrate, German speakers use "hydrogen" (aqueous substance) for "hydrogen", "oxygen" (acidic substance) for "oxygen", and "nitrogen" (suffocating substance) for "nitrogen", while English and some Romance languages use "sódio " for "sodium" and "potassium" for "kalio", and French, Italian, Greek, Portuguese and Polish prefer "azote/azot/azoto" (from roots meaning "lifeless") for "nitrogen". . . For purposes of international communication and commerce, the official names of chemical elements, both ancient and modern, are established by the International Union of Pure and Applied Chemistry (IUPAC), which has opted for a sort of international English language by using in traditional English names, even if an element's chemical symbol is based on a Latin or other traditional word, for example, accept "gold" instead of "aurum" as the name of element 79 (Ow). IUPAC prefers the British spellings "aluminum" and "cesium" to the American spellings "aluminum" and "cesium" and the American spelling "sulphur" to the British "sulphur". However, items that can be practically sold in large quantities in many countries still have national names that are used locally, and countries whose national language does not use the Latin alphabet are likely to use the IUPAC item names. According to IUPAC, chemical elements are not proper English names; Consequently, the full name of an element is generally not capitalized in English, even when derived from a proper noun, as in Californium and Einsteinium. The names of isotopes of chemical elements are also written without capital letters, e.g. B. carbon-12 or uranium-235. Chemical element symbols are always capitalized (see below). In the second half of the 20th century, physics laboratories were able to produce nuclei of chemical elements with half-lives too short for any appreciable number to exist simultaneously. These are also named by the IUPAC, which usually adopts the name chosen by the discoverer. This practice can lead to contention as to which research group actually discovered an element, an issue that has delayed naming elements with atomic number 104 or higher for a considerable time. (See Element name controversy.) The forerunners of such controversies were nationalist article names in the late 19th century. For example, lutetium was named after Paris, France. The Germans were reluctant to cede the naming rights to the French and often called it Cassiopeium. Likewise, the British discoverer of niobium originally called it columbium, referring to the New World. It was widely used as such by American publications prior to international standardization.

270

Chemical element

Chemical Symbols Specific Chemical Elements Before chemistry became a science, alchemists created obscure symbols for metals and common compounds. However, these were used as abbreviations in diagrams or procedures; there was no concept of atoms combining to form molecules. With his advances in the atomic theory of matter, John Dalton created his own simpler symbols based on circles to represent molecules. The current chemical notation system was invented by Berzelius. In this typographic system, the chemical symbols are not mere abbreviations, although each one is made up of letters from the Latin alphabet. They are designed as universal symbols for people of all languages and alphabets. The first of these symbols should be completely universal. Since Latin was the common language of science at the time, they were abbreviations based on the Latin names of metals. Cu comes from Cuprum, Fe comes from Ferrum, Ag from Argentum. Symbols were not followed by a period (period) as in abbreviations. Later chemical elements were also given unique chemical symbols based on the element's name, though not necessarily in English. For example, sodium has the chemical symbol "Na" after the Latin sodium. The same applies to “W” (wolfram) for tungsten, “Fe” (iron) for iron, “Hg” (hydragyre) for mercury, “Sn” (tin) for tin, “K” (potassium) for potassium, “Au ' (Aurum) for gold, 'Ag' (Argentum) for silver, 'Pb' (Plumbum) for lead, 'Cu' (Cuprum) for copper and 'Sb' (Stibium) for antimony. Chemical symbols are understood internationally when element names need to be translated. Sometimes there are differences. For example, the Germans used "J" instead of "I" for Jod so that the character would not be confused with a Roman numeral. The first letter of a chemical symbol is always capitalized, as in the examples above, and subsequent letters, if any, are always lowercase (lower case). Hence the symbols for Californium or Einsteinium are Cf and Es. General chemical symbols There are also symbols for series of chemical elements, for comparative formulas. They are capitalized and the letters are reserved so they cannot be used for specific item names. For example, an "X" denotes a group of variables within a class of compounds (although usually a halogen), while "R" is a radical denoting a compound structure such as a hydrocarbon chain. The letter "Q" is reserved for "heat" in a chemical reaction. "Y" is also often used as a general chemical symbol, although it is also the symbol for yttrium. "Z" is also often used as a group of general variables. "L" is used to represent a general ligand in inorganic and organometallic chemistry. "M" is also often used in place of a generic metal. At least two additional generic two-letter chemical symbols also have informal usage, "Ln" for any lanthanide element and "An" for any actinide element. Isotope Symbols Isotopes are distinguished by the atomic mass number (sum of protons and neutrons) for a given isotope of an element, combining that number with the appropriate element symbol. IUPAC prefers the superscript notation of isotopic symbols when practicable, e.g. B. 12C and 235U. However, other terms are also used, such as B. Carbon-12 and Uranium-235 or C-12 and U-235. As a special case, the three natural isotopes of the element hydrogen are often given as H for 1H (protium), D for 2H (deuterium) and T for 3H (tritium). This convention is easier to use in chemical equations and replaces the need to write the mass number of each atom. For example, the formula for heavy water could be written D2O instead of 2H2O.

271

Chemical element

272

Origin of the elements Only about 4% of the total mass of the universe consists of atoms or ions and is thus represented by chemical elements. This fraction makes up about 15% of all matter, with the rest of the matter (85%) being dark matter. The nature of dark matter is unknown, but it is not made up of atoms of chemical elements because it contains no protons, neutrons or electrons. (The remaining non-matter portion of the universe's mass is made up of the even more mysterious dark energy.) The 94 naturally occurring chemical elements in the universe are believed to have formed through at least four cosmic processes. Most of the hydrogen and helium in the universe was mainly produced in the first few minutes of the Big Bang. It is believed that three consecutive recurring processes produced the remaining elements. Stellar nucleosynthesis, a continuous process, produces every element from carbon to iron in atomic number, but little lithium, beryllium, or boron. Elements heavier in atomic number than iron, such as uranium and plutonium, are produced by explosive nucleosynthesis in supernovae and other catastrophic cosmic events. The spallation (fragmentation) of carbon, nitrogen, and oxygen by cosmic rays is important for the production of lithium, beryllium, and boron.

Estimated distribution of dark matter and dark energy in the Universe. Only that fraction of the mass and energy of the universe called "atoms" is made up of chemical elements.

During the early stages of the Big Bang, nucleosynthesis of hydrogen nuclei resulted in the production of hydrogen-1 (protonium, 1H) and helium-4 (4He), as well as a smaller amount of deuterium (2H) and very small amounts (since magnitude 10−10) of lithium and beryllium. Possibly even smaller amounts of boron were produced at the Big Bang, as observed in some very old stars, while carbon was not.[16] It is generally accepted that no elements heavier than boron were formed during the Big Bang. As a result, the original abundance of atoms (or ions) consisted of about 75% 1H, 25% 4He, and 0.01% deuterium, with only traces of lithium, beryllium, and perhaps boron.[17] Subsequent enrichment of galactic halos occurred due to stellar nucleosynthesis and supernova nucleosynthesis. [ ] However, the abundance of elements in intergalactic space can still resemble primordial conditions unless enriched by some means. On Earth (and elsewhere) small amounts of various elements continue to be produced from other elements as products of natural conversion processes. These include some produced by cosmic rays or other nuclear reactions (see cosmogenic and nucleogenic nuclides), and others produced as decay products of long-lived primordial nuclides. [ ] For example, traces (but detectable) of carbon-14 (14C). . ) are continuously produced in the atmosphere by cosmic rays hitting nitrogen atoms, and argon-40 (40Ar) is continuously produced by the decay of pristine but unstable potassium-40 (40K). In addition, three pristine but radioactive actinides, thorium, uranium, and plutonium, decay through a series of recurring but unstable radioactive elements, such as radium and radon, transiently present in any sample of these metals or their minerals or compounds.

Chemical element Seven other radioactive elements, technetium, promethium, neptunium, americium, curium, berkelium, and californium, are found only incidentally in natural materials, which arise as single atoms through the natural fission of the nuclei of various heavy elements or in other rare processes. Human technology has produced several additional elements beyond those first 98, and those up to atomic number 118 are now known.

Abundance The graph below (note the logarithmic scale) shows the abundance of the elements in our solar system. The table shows the twelve most common elements in our galaxy (estimated spectroscopically), measured in parts per million, by mass. [ ] Nearby galaxies that evolved in a similar fashion show a corresponding enrichment of elements heavier than hydrogen and helium. More distant galaxies look like they did in the past, so their richness of elements is closer to the original mix. However, because physical laws and processes appear to be common throughout the visible universe, scientists expect these galaxies to have evolved elements in similar abundance. The abundance of elements in the Solar System is consistent with their origin from Big Bang nucleosynthesis and several supernova progenitor stars. Hydrogen and helium are very common products of the Big Bang, but the next three elements are rare, having had little time to form at the Big Bang and are not produced in stars (they are, however, produced in small quantities by the decay of heavier ones elements) in interstellar dust as a result of cosmic ray impact). Beginning with carbon, elements in stars are created by the accumulation of alpha particles (helium nuclei), resulting in an alternating greater abundance of elements with uniform atomic numbers (these are also more stable). In general, such elements, up to and including iron, are formed in large stars in the process of supernovae. Iron-56 is particularly common because it is the most stable element that can be easily made from alpha particles (a decay product of radioactive nickel-56 made from 14 helium nuclei). Elements heavier than iron form in large stars in energy-absorbing processes, and their abundance in the Universe (and on Earth) generally decreases with atomic number. The abundance of chemical elements on Earth varies from air to crust and ocean to different types of life. The element abundance of the Earth's crust differs from that of the Universe (and also the Sun and heavy planets such as Jupiter) primarily in the selective loss of the lighter elements (hydrogen and helium) as well as the volatile neon, carbon, nitrogen and sulphur. B. by solar heating in the early formation of the solar system. Aluminum is also much more common on Earth and the Earth's crust than in the Universe and Solar System, but the composition of Earth's mantle (which contains more magnesium and iron than aluminum) tends to reflect that of the Universe, except as noted. loss of volatile elements. The composition of the human body, on the other hand, more closely follows the composition of seawater, except that the human body has additional stores of carbon and nitrogen needed to form the proteins and nucleic acids characteristic of living organisms. Certain types of organisms require certain additional elements, for example magnesium in the chlorophyll of green plants, calcium in the shells of molluscs, or iron in the hemoglobin in the red blood cells of vertebrates.

273

Chemical element

274

Abundance of chemical elements in the solar system. Hydrogen and helium are the most common since the Big Bang. The next three elements (Li, Be, B) are rare because they are poorly synthesized in the Big Bang and also in stars. The two general trends in the remaining stellar elements produced are: (1) a change in the abundance of even- and odd-numbered elements, and (2) an overall decrease in abundance as the elements become heavier. Iron is particularly common because it is the lowest energy nuclide that can be produced by helium fusion in supernovae.

elements in our galaxy

Parts per million by mass

hydrogen

739.000

Helium

240.000

oxygen

10.400

Money

4.600

Neon

1.340

Eisen

1.090

nitrogen

960

silicon

650

Magnesium

580

sulfur

440

Potassium

210

Nickel

100

Chemical element

275

History Evolving definitions The concept of "element" as an indivisible substance evolved through three main historical phases: classical definitions (such as those of the ancient Greeks), chemical definitions, and atomic definitions. Classical Definitions Ancient philosophy posited a number of classical elements to explain the patterns observed in nature. These elements originally referred to earth, water, air, and fire rather than the chemical elements of modern science. The term "elements" (stoicheia) was first used around 360 BC. used by the Greek philosopher Plato. C. in his Timaeus dialogue, which contains a discussion of the composition of inorganic and organic bodies and is a speculative treatise on chemistry. Plato believed that the elements introduced by Empedocles a century earlier were composed of small polyhedral forms: tetrahedron (fire), octahedron (air), icosahedron (water), and cube (earth).[18][19]

Mendeleev's periodic table of 1869

Aristotle, c. 350 BC Chr. C. also used the term Stoicheia and added a fifth element called ether, which formed the sky. Aristotle defined an element as: Element – one of those bodies into which other bodies can be divided and which itself cannot be divided into others.[20] Chemical definitions In 1661 Robert Boyle proposed his theory of corpuscularism, which favored the analysis of matter as made up of irreducible units of matter (atoms), choosing not to side with Aristotle's view of the four elements or Paracelsus' view of the three Placing elements on basic elements left open the question of the number of elements. [] The first modern list of chemical elements was provided by Antoine Lavoisier's Elements of Chemistry in 1789, which included thirty-three elements, including light and calories. [21] In 1818, Jöns Jakob Berzelius determined the atomic weights of 45 of the then accepted 49 elements. Dmitri Mendeleev had 66 elements in his 1869 periodic table.

Chemical element

276 From Boyle until the early 20th century, an element was defined as a pure substance that could not be broken down into a simpler substance.[] In other words, a chemical element cannot be transformed into other chemical elements by chemical processes. Elements during this period were generally distinguished by their atomic weights, a property that is fairly accurately measurable with available analytical techniques.

Dimitri Mendelejew

Atomic Definitions The discovery in 1913 by the English physicist Henry Moseley that the nuclear charge is the physical basis for an atom's atomic number was further refined when the nature of protons and neutrons was recognized and eventually led to the current definition of an element, the atomic based number (number of protons per nucleus). Using atomic numbers instead of atomic weights to distinguish elements has greater predictive value (since these numbers are integers) and also resolves some ambiguity in the chemistry-based view due to different properties of isotopes and allotropes within the same element. Currently, IUPAC defines the existence of an element as having isotopes with a lifetime greater than the 10-14 seconds it takes for the nucleus to form an electron cloud.[22] By 1914, 72 elements were known, all of natural origin.[23] The remaining natural elements were discovered or isolated in later decades, and several additional Henry Mosley elements were also made synthetically, much of this work being initiated by Glenn T. Seaborg. In 1955 element 101 was discovered and named after D.I. named Mendelevium. Mendeleev, who was the first to periodically arrange elements. Recently, the synthesis of element 118 was reported in October 2006 and the synthesis of element 117 in April 2010.[24]

Discovery and Recognition of Various Elements Ten materials known to various prehistoric cultures are known today as chemical elements: carbon, copper, gold, iron, lead, mercury, silver, sulfur, tin and zinc. Three other materials now accepted as elements, arsenic, antimony, and bismuth, were recognized as distinct substances before AD 1500. Phosphorus, cobalt, and platinum were isolated before 1750. Most remaining naturally occurring chemical elements had been identified and characterized by the 1900s, including: • Industrial materials known today such as aluminum, silicon, nickel, chromium, magnesium and tungsten • Reactive metals such as lithium, sodium, potassium and calcium • The halogens fluorine, chlorine, bromine and iodine • Gases such as hydrogen, oxygen, nitrogen, helium, argon, and neon • Most rare earth elements, including cerium, lanthanum, gadolinium, and neodymium and

Chemical Element • The most common radioactive elements, including uranium, thorium, radium and radon. Elements isolated or produced since 1900 include: • The three remaining undiscovered and regularly encountered stable natural elements: hafnium, lutetium and rhenium • Plutonium, first synthesized by Glenn T. Seaborg in 1940 but now also recognized as a long-lived natural element Occurring elements • The three incidental natural elements (neptunium, promethium, and technetium) that were first produced synthetically but were later discovered in small amounts in certain geological samples • Three rare decay products of uranium or thorium (astatine, francium, and protactinium), and • Various synthetic transuranic elements starting with americium, curium, berkelium and californium

Newly Discovered Elements The first transuranium element (an element with an atomic number greater than 92) to be discovered in 1940 was neptunium. Since 1999, the IUPAC/IUPAP Joint Working Group has been examining claims for the discovery of new elements. As of May 2012, only elements up to 112, copernicium, as well as element 114 flerovium and element 116 livermorium have been confirmed as discovered by IUPAC, while the synthesis of elements 113, 115 has been claimed. the discovery of element 112 was acknowledged in 2009, and the name “copernicium” and the atomic symbol “Cn” were proposed.[25] The name and symbol were officially approved by IUPAC on February 19, 2010.[26] The heaviest element believed to have been synthesized to date is element 118, ununocio, on October 9, 2006 by the Flerov Nuclear Reactions Laboratory in Dubna, Russia. , in 2009. [] IUPAC officially recognized flerovium and liver, elements 114 and 116 in June 2011 and approved their names in May 2012. [28]

List of 118 Known Chemical Elements The sortable table below lists all 118 known chemical elements, with names linked to Wikipedia articles for each. • The ordinal number, name, and symbol serve independently as unique identifiers. • names are those accepted by IUPAC; Working names for newly produced items that have not yet been officially named are in parentheses. • Group, point and block refer to the position of an element in the periodic table. • The state of aggregation (solid, liquid or gaseous) applies to standard temperature and pressure conditions (STP). they have been engineered but are not known to occur naturally. • The description summarizes the properties of an element using the broad categories commonly represented in the periodic table: actinides, alkali metals, alkaline earth metals, halogens, lanthanides, metals, metalloids, noble gases, nonmetals, and transition metals.

277

Chemical element

278

List of elements atomic number

Name

Period block of the symbol group

Stated in STP

Idea

description

hydrogen

Gas

Originally

i was metal

Helium

Him

Gas

Originally

Forerunner

Lithium

Fest

Originally

Alkalimetall

Beryllium

His

Fest

Originally

alkaline earth metal

Boro

Page

Fest

Originally

Metalloid

Money

Page

Fest

Originally

i was metal

nitrogen

Norte

fifteen

Page

Gas

Originally

i was metal

oxygen

sixteen

Page

Gas

Originally

i was metal

Fluor

Page

Gas

Originally

Halogen

Neon

Sim

Page

Gas

Originally

Forerunner

Sodium

Von

Fest

Originally

Alkalimetall

Magnesium

Fest

Originally

alkaline earth metal

Aluminium

Alabama

Page

Fest

Originally

Metal

silicon

Page

Fest

Originally

Metalloid

fifteen

Phosphor

PAG

fifteen

Page

Fest

Originally

i was metal

sixteen

sulfur

sixteen

Page

Fest

Originally

i was metal

Chlor

Page

Gas

Originally

Halogen

Argon

Arkansas

Page

Gas

Originally

Forerunner

Potassium

Fest

Originally

Alkalimetall

Soccer

California

Fest

Originally

alkaline earth metal

Scandium

Caroline all on

Fest

Originally

transition metal

Titan

Von

Fest

Originally

transition metal

Vanadium

Fest

Originally

transition metal

Chrom

Fest

Originally

transition metal

Mangan

Minnesota

Fest

Originally

transition metal

Eisen

trust

Fest

Originally

transition metal

Cobalt

company

Fest

Originally

transition metal

Nickel

Fest

Originally

transition metal

copper

Fest

Originally

transition metal

Zink

Fest

Originally

transition metal

Gallium

Georgia

Page

Fest

Originally

Metal

Deutschland

Page

Fest

Originally

Metalloid

Arsenic

fifteen

Page

Fest

Originally

Metalloid

Selenium

sixteen

Page

Fest

Originally

i was metal

Brom

Brothers

Page

Fluid

Originally

Halogen

Krypton

Page

Gas

Originally

Forerunner

Chemical element

279 37

Rubidium

Fest

Originally

Alkalimetall

Strontium

Herr

Fest

Originally

alkaline earth metal

Itrio

Fest

Originally

transition metal

Zirconium

Fest

Originally

transition metal

niobium

Fest

Originally

transition metal

molybdenum

Mes

Fest

Originally

transition metal

technician

Fest

in the interim

transition metal

Brunft

Fest

Originally

transition metal

we were born

Fest

Originally

transition metal

Palladium

Fest

Originally

transition metal

Talk

Agriculture

Fest

Originally

transition metal

Cadmium

Fest

Originally

transition metal

Indonesian

Page

Fest

Originally

Metal

Lata

nice

Page

Fest

Originally

Metal

antimony

fifteen

Page

Fest

Originally

Metalloid

Tellurium

Him

sixteen

Page

Fest

Originally

Metalloid

Iodine

she

Page

Fest

Originally

Halogen

Xenon

Auto

Page

Gas

Originally

Forerunner

cesium

Fest

Originally

Alkalimetall

Barium

Bachelor of Arts

Fest

Originally

alkaline earth metal

Lantano

Fest

Originally

Lanthanid

Cer

Fest

Originally

Lanthanid

praseodimio pr

Fest

Originally

Lanthanid

neodymium

Dakota do Norte

Fest

Originally

Lanthanid

Prometheus

Fest

in the interim

Lanthanid

Samaria

little bit

Fest

Originally

Lanthanid

Europa

Fest

Originally

Lanthanid

Gadolinium

Di-s

Fest

Originally

Lanthanid

Sixty-five

Terbio

Tuberculosis

Fest

Originally

Lanthanid

Dysprosium

to die

Fest

Originally

Lanthanid

holmio

Fest

Originally

Lanthanid

coelho

Fest

Originally

Lanthanid

we're still

Fest

Originally

Lanthanid

Ytterbium

Fest

Originally

Lanthanid

Paris

Fest

Originally

Lanthanid

We stayed

H.f.

Fest

Originally

transition metal

Tantalus

For

Fest

Originally

transition metal

Wolfram

Fest

Originally

transition metal

guide

Eras

Fest

Originally

transition metal

Chemical element

280 76

eight

Fest

Originally

transition metal

irídio

Fest

Originally

transition metal

platinum

point it out

Fest

Originally

transition metal

Gold

Fest

Originally

transition metal

mercury

Fluid

Originally

transition metal

Cut

Page

Fest

Originally

Metal

Lead

Page

Fest

Originally

Metal

bismuth

fifteen

Page

Fest

Originally

Metal

Polonium

After

sixteen

Page

Fest

in the interim

Metal

Astato

Page

Fest

in the interim

Halogen

Radon

Page

Gas

in the interim

Forerunner

France

Fest

in the interim

Alkalimetall

Radio

Royal Academy of Fine Arts

Fest

in the interim

alkaline earth metal

action

Fest

in the interim

Actin

Thorium

Fest

Originally

Actin

Protactinium

Pennsylvania

Fest

in the interim

Actin

Career

Fest

Originally

Actin

Neptune

Public notary

Fest

in the interim

Actin

Plutonium

Fest

Originally

Actin

American

Military

Fest

in the interim

Actin

cut

Fest

in the interim

Actin

Berkelio

Negro

Fest

in the interim

Actin

California

See.

Fest

in the interim

Actin

einstenio

Fest

synthetic

Actin

100

fermio

Fest

synthetic

Actin

101

Mendelejew

Maryland

Fest

synthetic

Actin

102

Edel

Not

Fest

synthetic

Actin

103

Lawrence

Fest

synthetic

Actin

104

RutherfordioRf

synthetic

transition metal

105

I do not know

Database

synthetic

transition metal

106

seeborgio

synthetic

transition metal

107

bohrio

synthetic

transition metal

108

Hassio

synthetic

transition metal

109

Meitner

Monte

synthetic

110

Darmstadtio

synthetic

111

Röntgenio

synthetic

112

Copernicus

synthetic

113

(on one)

Not

Page

synthetic

114

fleróvio

Florida

Page

synthetic

transition metal

Chemical element

281 115

(A penny) Whoops

fifteen

Page

synthetic

116

Livermorio

sixteen

Page

synthetic

117

(One-seven) New

Page

synthetic

118

(one night)

Page

synthetic

need

Literature [3] See chronology on page 10 of [22] Transactinide-2 (http://www.kernchemie.de/Transactinides/Transactinide-2/transactinide-2.html). www.kernchemie.de

Additional Reading • Ball, P (2004). The Elements: A Very Brief Introduction. Oxford University Press. ISBN0-19-284099-1. • Emsley, J (2003). The Building Blocks of Nature: An A to Z Guide to the Elements. Oxford University Press. ISBN0-19-850340-7. • Grau, T. (2009). The Elements: A Visual Exploration of Every Known Atom in the Universe. Black Dog and Leventhal Publishers Inc. ISBN1-57912-814-9. • Scerri, ER (2007). The periodic table, its history and meaning. Oxford University Press. • Strathern, P (2000). Mendeleev's Dream: The Search for the Elements. Hamish Hamilton Ltd. ISBN0-241-14065-X.

External Links • Videos for each article (http://periodicvideos.com/) from the University of Nottingham

Nuclear physics isotopes

Nucleus Nuclei(p,n) nuclear force nuclear reaction

Isotope

Isotopes are variants of a particular chemical element, such that while all isotopes of a particular element share the same number of protons and electrons, each isotope differs from the others in its number of neutrons. The term isotope is composed of the Greek roots isos (ἴσος "same") and topos (τόπος "place") and means "the same place". Thus, different isotopes of a single element occupy the same position in the three natural isotopes of hydrogen. The fact that every isotope has a periodic table. The number of protons in a proton makes them all variants of hydrogen: the isotopic identity is given within the atomic nucleus and is uniquely identified by the number of neutrons. From left to right, the isotopes are protium (1H) with zero neutrons, deuterium (2H) with one neutron, and tritium (3H) with two elements, but a given element can have neutrons. basically have any number of neutrons. The number of nucleons (protons and neutrons) in the nucleus is the mass number, and each isotope of a given element has a different mass number. For example, carbon-12, carbon-13, and carbon-14 are three isotopes of the element carbon with mass numbers 12, 13, and 14, respectively. The atomic number of carbon is 6, meaning that each carbon atom has 6 protons, so the number of neutrons in these isotopes is 6, 7 and 8, respectively.

Isotope vs. Nuclide A nuclide is an atom with a certain number of protons and neutrons in the nucleus, eg carbon-13 with 6 protons and 7 neutrons. The nuclide concept (which refers to individual nuclear species) emphasizes nuclear properties over chemical properties, while the isotope concept (which summarizes all the atoms of each element) emphasizes chemical properties over nuclear properties. The number of neutrons has a dramatic effect on nuclear properties, but their effect on chemical properties is negligible for most elements and still quite small for the lightest elements, although it does matter in some circumstances (for hydrogen, the lightest of all ). elements, the isotope effect is large enough to strongly affect biology). As isotope is the older term, it is better known as nuclide and is sometimes still used in contexts where nuclide might be more appropriate, such as B. in nuclear technology and nuclear medicine.

Notation An isotope and/or nuclide is specified by the name of the specific element (this implicitly indicates the atomic number) followed by a hyphen and the mass number (e.g. helium-3, helium-4, carbon-12, carbon- 14 , uranium-235 and uranium-239).[1] When a chemical symbol is used, for example "C" for carbon, the standard notation (now known as "AZE notation" because A is the mass number, Z is the atomic number, and E for the element) is intended to indicate the number of nucleons with a superscript in the upper left corner of the chemical symbol and to indicate the atomic number with a subscript in the lower left corner (e.g. 3 2He, 4 2He, 12 6C, 14 6C, 235 92U and 239 [ 2 ] 92U ). Because the element symbol implies the atomic number, it is common to specify only the mass number in the superscript and omit the subscript (e.g. 3He, 4He, 12C, 14C, 235U, and 239U, respectively). The letter m is sometimes added after the mass number to indicate a nuclear isomer, a metastable one

282

Isotope or energetically excited nuclear state (instead of the lower-energy ground state), e.g. 180m 73Ta (tantalum-180m).

Radioactive, pristine and stable isotopes Some isotopes are radioactive and are therefore referred to as radioisotopes or radionuclides, while others never decay radioactively and are referred to as stable isotopes. For example, 14C is a radioactive form of carbon, while 12C and 13C are stable isotopes. There are about 339 natural nuclides on earth, [] of which 288 are primordial nuclides, ie they have existed since the formation of the solar system. The primordial nuclides include 35 nuclides with very long half-lives (more than 80 million years) and 254 which are formally considered "stable isotopes" [] since no decays have been observed. In most cases, for obvious reasons, when an element has stable isotopes, those isotopes dominate the element abundance found on Earth and in the solar system. However, in the case of three elements (tellurium, indium, and rhenium), the most abundant isotope in nature is actually one (or two) extremely long-lived radioisotopes of the element, even though these elements have one or more stable isotopes. . The theory predicts that many apparently "stable" isotopes are radioactive, with extremely long half-lives (this does not account for the possibility of proton decay, which would render all nuclides unstable). Of the 254 nuclides whose decay has never been observed, only 90 of them (all of the first 40 elements) are theoretically stable to all known decay forms. Element 41 (niobium) is theoretically unstable by spontaneous fission, but this has never been demonstrated. In theory, many other stable nuclides are energetically susceptible to other known forms of decay, such as alpha decay or double beta decay, but decay products have not yet been observed, hence these isotopes are referred to as "observation-stable". The predicted half-lives for these nuclides often far exceed the estimated age of the universe, and in fact there are also 27 known radionuclides (see primordial nuclide) with half-lives longer than the age of the universe. If one adds up the artificially generated radioactive nuclides, over 3,100 nuclides are currently known.[3] These include 905 nuclides that are stable or have half-lives longer than 60 minutes. See the list of nuclides for more information.

History Radioactive isotopes The existence of isotopes was first suggested by radiochemist Frederick Soddy in 1912 based on studies of radioactive decay chains, which indicate about 40 different species described as radioelements (ie radioactive elements) between uranium and lead. , although the periodic table only allowed 11 elements from uranium to lead.[4][5] Several attempts to chemically separate these new radio elements failed.[6] For example, in 1910 Soddy had shown that mesothorium (later shown to be 228Ra), radium (226Ra, the longest-lived isotope), and thorium X (224Ra) cannot be separated. [] Attempts to include radio elements in the periodic table led Soddy and Kazimierz Fajans to independently propose their law of radioactive shift in 1913, according to which alpha decay produced an element two places to the left of the table, while beta decay emitted one generated element one place to the right.[7] Soddy realized that the emission of an alpha particle followed by two beta particles resulted in the formation of an element that was chemically identical to the original element but had a four-unit lighter mass and different radioactive properties. Soddy suggested that several types of atoms (with different radioactive properties) could occupy the same place in the table. For example, the alpha decay of uranium-235 forms thorium-231 while the beta decay of actinium-230 forms thorium-230". by Margaret Todd, a

283

Isotope Scottish doctor and family friend, during a conversation explaining his ideas.[][8][9][][10][11] In 1914, T. W. Richards found differences between the atomic weight of lead and various mineral sources, which are due to variations in isotopic composition due to different radioactive sources.[6][12]

Stable Isotopes The first evidence of isotopes of a stable (non-radioactive) element was found by J.J. Thomson in 1913 as part of his research on the composition of canal rays (positive ions).[13][14] Thomson passed streams of neon ions through an electric and magnetic field and measured their deflection by placing a photographic plate in their path. Each ray created a bright spot on the disk where it struck. Thomson observed two separate points of light on the photographic plate (see picture), indicating two different deflection parabolas. Thomson eventually concluded that some of the atoms in neon gas have a greater mass than the rest. Below J.J. Thomson's right, F.W. Aston later discovered that different stable isotopes for photographic plates are the separate impact traces of different elements using a mass spectrograph . In 1919 Aston studied the two isotopes of neon: neon-20 and neon with sufficient resolution to show that the two isotopic masses are neon-22. very close to the integers 20 and 22, and neither equals the known molar mass (20.2) of neon gas. This is an example of Aston's integer rule for isotopic masses, which states that large deviations from integer elemental molar masses are primarily due to the element being a mixture of isotopes. Aston also showed that the molar mass of chlorine (35.45) is a weighted average of the near-integer masses of the two isotopes Cl-35 and Cl-37.[15]

Different Properties Between Isotopes Chemical and Molecular Properties A neutral atom has the same number of electrons and protons. Therefore, different isotopes of a given element all have the same number of protons and a similar electronic structure. Since the chemical behavior of an atom is largely determined by its electronic structure, different isotopes show almost identical chemical behavior. The main exception to this is the kinetic isotope effect: due to their greater mass, heavier isotopes tend to react slightly more slowly than lighter isotopes of the same element. This is more pronounced with protium (1H) and deuterium (2H) since deuterium has twice the mass of protium. The mass effect between deuterium and the relatively light protium also affects the behavior of their respective chemical bonds, changing the center of gravity (reduced mass) of atomic systems. However, for heavier elements, which have more neutrons than lighter elements, the ratio of nuclear mass to collective electronic mass is much larger and the relative mass difference between isotopes is much smaller. For these two reasons, the impact of the mass difference on chemistry is generally negligible.

284

Isotope

Likewise, two molecules that differ only in the isotopic nature of their atoms (isotopologues) have identical electronic structure and therefore almost indistinguishable physical and chemical properties (again, deuterium is the major exception to this rule). The vibrational modes of a molecule are determined by its shape and the masses of its constituent atoms. As a result, isotopologues will have different sets of vibrational modes. Because the vibrational modes allow a molecule to absorb photons of appropriate energy, isotopologues have different optical properties in the infrared.

Nuclear Properties and Stability Atomic nuclei consist of protons and neutrons held together by the remaining strong force. Since protons are positively charged, they repel each other. Neutrons, half-lives of isotopes. Note that the stable isotope diagram deviates from the Z=N line as the number of Z elements becomes electrically neutral. They stabilize the core in two ways. Their joint presence separates the protons easily, reducing the electrostatic repulsion between the protons, and they exert the nuclear attraction on each other and on the protons. For this reason, one or more neutrons are needed for two or more protons to unite to form an atomic nucleus. As the number of protons increases, so does the ratio of neutrons to protons, which is required for a stable nucleus (see graphic on the right). For example, although the neutron:proton ratio of 3 2He is 1:2, the neutron:proton ratio of 238 92U is greater than 3:2. Some lighter elements have stable nuclides with a 1:1 (Z=N) ratio. Nuclide 40 20Ca (calcium-40) is observed to be the heaviest stable nuclide with the same number of neutrons and protons; (In theory, the heaviest stall is Sulphur-32). All stable nuclides heavier than Calcium-40 contain more neutrons than protons.

Isotope Numbers per Element Of the 80 elements with a stable isotope, the largest number of stable isotopes observed for any element is ten (for the element tin). No element has nine stable isotopes. Xenon is the only element with eight stable isotopes. Four elements have seven stable isotopes, eight have six stable isotopes, ten have five stable isotopes, nine have four stable isotopes, five have three stable isotopes, 16 have two stable isotopes (counting 180m73Ta as stable), and 26 elements have only one single stable isotope (of which 19 are the so-called mononucleotide elements, which have a single original stable isotope that dominates and fixes the atomic weight of the natural element with high precision; there are also 3 radioactive mononucleotide elements).[] In total , there are 254 radioactive elements, nuclides whose decay has not been observed. For the 80 elements that have one or more stable isotopes, the average number of stable isotopes is 254/80 = 3.2 isotopes per element.

285

Isotope

286

Number of even and odd nucleons Z, N (containing hydrogen-1 as OE) p,n EE OO EO OE Total Stable 148

254

All original 170

289

long lasting

The proton:neutron ratio is not the only factor affecting nuclear stability. It also depends on the similarity or strangeness of their atomic number Z, the number of neutrons N and consequently their sum, the mass number A. The strangeness of Z and N tends to reduce the core binding energy, making them odd cores, generally less stable. This marked difference in nuclear binding energy between neighboring nuclei, particularly of odd A isobars, has important consequences: unstable isotopes with suboptimal neutron or proton numbers decay by beta decay (including positron decay), electron capture, or other exotic means, such as spontaneous nuclear fission and cumulus cloudburst. The most stable nuclides are proton and neutron pairs where all Z, N, and A numbers are even. Stable odd A-nuclides are divided (more or less evenly) into odd proton-neutron nuclides and even proton-odd neutron nuclides. Nuclei with odd protons and odd neutrons are the rarest. Even nuclides with atomic number proton pair, neutron pair (EE), comprising 148/254 = ~58% of all stable nuclides, necessarily have spin 0 due to pairing. There are 148 stable pair-pair nuclides, representing ~58% of the 254 stable nuclides turn off. There are also 22 long-lived primordial pair-pair nuclides. As a result, each of the 41 even elements 2 through 82 has at least one stable isotope, and most of these elements have multiple ancestral isotopes. Half of these even elements have six or more stable isotopes. The extreme stability of helium-4, due to a double pairing of 2 protons and 2 neutrons, prevents nuclides with five or eight nuclei from existing long enough to serve as a platform for the accumulation of heavier elements by fusion. ).

Long-term odd-even decay

half-life

113 beta 48Cd

7,7 × 1015 z

123 beta 52Te

6,0 × 1014 z

147 beta 62Sm

1,06 × 1011 z

235 92U

7,04 × 108 e

Alpha

These 53 stable nuclides have an even number of protons and an odd number of neutrons. They are outnumbered by the even isotopes, which are about three times more numerous. Among the 41 even-Z elements that have a stable nuclide, only three elements (argon, cerium, and lead) do not have stable odd nuclides. One element (tin) has three. There are 24 elements with one odd even nuclide and 13 with two odd even nuclides. Of the 35 primordial radionuclides, there are four odd and even nuclides (see table at right), including the fissile 235 92U. Because of their odd number of neutrons, odd-numbered nuclides tend to have large neutron capture cross-sections due to the energy resulting from neutron pairing effects. These stable nuclides of even protons and odd neutrons are rather rare in nature, usually because, in order to form and enter primordial abundance,

The isotope must have escaped neutron capture to form other stable paired isotopes, both during the s-neutron capture process and during the r-process during nucleosynthesis in stars. Because of this, only 195 78Pt and 9 4Be are the most abundant isotopes of their element. Stable nuclides of even protons and odd neutrons of atomic number 48, stabilized by their even number of paired neutrons, form the most stable isotopes of odd elements; the few foreign nuclides include the others. There are 41 odd elements with Z = 1 to 81, 39 of which have stable isotopes (elements technetium (43Tc) and promethium (61Pm) have no stable isotopes). Of these 39 odd-Z elements, 30 elements (including hydrogen-1, where 0 neutrons are even) have a stable odd-even isotope and nine elements: chlorine (17Cl), potassium (19K), copper (29Cu), gallium (31Ga ) , bromine (35Br), silver (47Ag), antimony (51Sb), iridium (77Ir), and thallium (81Tl), each with two stable odd and even isotopes. That makes a total of 30 + 2(9) = 48 stable odd and even isotopes. There are also five long-lived primordial radioactive odd-numbered isotopes, 87 37Rb, 115 49In, 187 75Re, 151 63Eu, and 209 18 83Bi. The last two have been declining recently, with half-lives in excess of 10 years. Only five stable nuclides contain an odd number of protons and an odd number of neutrons. The first four "odd" nuclides occur in low-mass nuclides, where the conversion of a proton into a neutron or vice versa would lead to a strongly asymmetric proton-neutron ratio (2 1H, 6 3Li, 10 5B and 14 7N; spins 1 , 1, 3, 1). The only other fully "stable" odd nuclide is 180m 73Ta (spin 9), the only primordial nuclear isomer whose decay has not yet been observed despite experimental attempts.[16] Therefore, all observably stable odd nuclides have non-zero integer spin. This is because the single unpaired neutron and unpaired proton have a stronger nuclear attraction to each other when their spins are aligned (giving a total spin of at least 1 unit) rather than anti-aligned. See deuterium for the simplest case of this nuclear behavior. Many rare radionuclides (such as tantalum-180) with relatively short half-lives are known. They usually decay to their almost uniform isobars, which have paired protons and neutrons. Of the nine original odd nuclides (five stable and four radioactive with long half-lives), only 14 7N is the most common isotope of a common element. This is because it is part of the CNO cycle. The nuclides 6 3Li and 10 5B are minor isotopes of elements that are rare compared to other light elements, while the other six

287

Isotope

288

Isotopes represent only a small percentage of the natural abundance of their elements. For example, 180m 73Ta is believed to be the rarest of the 254 stable isotopes. odd number of neutrons

Neutron number parity (1H with 0 neutrons included as pairs) N

from odd

Stable

196

long lasting

All original 223

Actinides with an odd number of neutrons are generally fissile (with thermal neutrons), while those with an even number of neutrons are generally not, although fissile with fast neutrons. Only 195 78Pt, 9 4Be and 14 7N have an odd number of neutrons and are the most abundant isotopes of their element.

Naturally occurring elements consist of one or more naturally occurring isotopes. Unstable (radioactive) isotopes are either primordial or postprimordial. The original isotopes were the product of stellar nucleosynthesis or some other type of nucleosynthesis such as B. the spallation of cosmic rays, and persist to this day because their rate of decay is so slow (e.g. uranium-238 and potassium-40). . Postprimordial isotopes have been generated by cosmic ray bombardment as cosmogenic nuclides (e.g. tritium, carbon-14) or by the decay of a radioactive primordial isotope to a radiogenic radioactive daughter nuclide (e.g. uranium to radium). Some isotopes also continue to be naturally synthesized as nucleogenic nuclides by another natural nuclear reaction, such as when neutrons from natural nuclear fission are absorbed by another atom. As discussed above, only 80 elements have stable isotopes and 26 of them have only one stable isotope. Therefore, about two-thirds of the stable elements on Earth occur naturally in multiple stable isotopes, with ten being the highest number of stable isotopes for any element, for tin (50Sn). There are approximately 94 elements that occur naturally on earth (up to and including plutonium), although some are only detectable in very small amounts, such as: B. Plutonium-244. Scientists estimate that naturally occurring elements on Earth (some only as radioisotopes) exist in a total of 339 isotopes (nuclides).[17] Only 254 of these naturally occurring isotopes are stable in the sense that their decay has never been observed today. Another 35 primordial nuclides (up to a total of 289 primordial nuclides) are radioactive with known half-lives, but have half-lives greater than 80 million years, allowing them to have existed since the beginning of the solar system. See the list of nuclides for more information. All known stable isotopes occur naturally on Earth; the other naturally occurring isotopes are radioactive, but they are present on Earth because of their relatively long half-lives or because of other ongoing natural means of production. These include the aforementioned cosmogenic nuclides, nucleogenic nuclides, and any radiogenic radioisotopes formed by the continuous decay of a primordial radioactive isotope, such as radon and radium from uranium. About 3,000 additional radioactive isotopes not found in nature have been created in nuclear reactors and particle accelerators. Many short-lived isotopes not found naturally on Earth have also been observed by spectroscopic analysis to form naturally in stars or supernovae. An example is aluminum-26, which does not occur naturally on Earth but is found in abundance at astronomical levels.

Isotope The tabulated atomic masses of the elements are average values that explain the presence of several isotopes with different masses. Before the discovery of isotopes, empirically determined non-integer values of atomic masses puzzled scientists. For example, a chlorine sample contains 75.8% chlorine-35 and 24.2% chlorine-37, giving an average atomic mass of 35.5 atomic mass units. According to the generally accepted theory of cosmology, only hydrogen and helium isotopes, trace amounts of some lithium and beryllium isotopes and perhaps some boron were produced at the big bang, while all other isotopes were later synthesized in stars and supernovae and in interactions between energetic particles such as cosmic rays and before produced isotopes. (See Nucleosynthesis for details of the various processes thought to be responsible for isotope production.) After the Solar System's initial coalescence, the isotopes were reallocated according to their mass, and the isotopic composition of the elements varies slightly from planet to planet . This sometimes makes it possible to trace the origin of meteorites.

Atomic Mass of Isotopes The atomic mass (mr) of an isotope is primarily determined by its mass number (ie the number of nucleons in its nucleus). The small corrections are due to the binding energy of the nucleus (see mass defect), the small mass difference between proton and neutron and the mass of the electrons associated with the atom, the latter due to the electron:nucleon ratio. differs between isotopes. The mass number is a dimensionless quantity. Atomic mass, on the other hand, is measured using the atomic mass unit based on the mass of the carbon-12 atom. It is indicated by the symbols "u" (for Unified Atomic Mass Unit) or "Da" (for Dalton). The atomic masses of an element's natural isotopes determine the element's atomic mass. If the element contains N isotopes, the following expression for the average atomic mass applies:

where m1, m2, ..., mN are the atomic masses of each individual isotope and x1, ..., xN are the relative abundances of these isotopes.

Isotopic Purification Applications There are several applications that take advantage of the properties of different isotopes of a given element. Isotope separation is a significant technological challenge, especially for heavy elements such as uranium or plutonium. Lighter elements such as lithium, carbon, nitrogen and oxygen are usually separated from their compounds such as CO and NO by gas diffusion. The separation of hydrogen and deuterium is unusual in that it is based on chemical rather than physical properties, as in the Girdler sulfide process. Uranium isotopes have been separated by mass by gas diffusion, gas centrifugation, laser ionization separation, and (in the Manhattan Project) a type of production mass spectrometry.

Using Chemical and Biological Properties • Isotopic analysis is the determination of the isotopic signature, the relative abundance of isotopes of a given element in a given sample. Significant isotope variations of C, N and O can occur, particularly in the case of biogenic substances. The analysis of these has a wide range of applications, for example to detect adulteration of food [ ] or the geographical origin of products using isoscapes. The identification of certain meteorites as originating from Mars is based in part on the isotopic signature of the residual gases they contain.[] • Isotopic substitution can be used to determine the mechanism of a chemical reaction through the kinetic isotope effect.

289

Isotope

290

• Another common application is isotope tagging, the use of unusual isotopes as tracers or markers in chemical reactions. Normally, the atoms of a given element are indistinguishable from each other. However, using isotopes of different masses, even different stable non-radioactive isotopes can be distinguished using mass spectrometry or infrared spectroscopy. For example, “stable isotope labeling with amino acids in cell culture (SILAC)” uses stable isotopes to quantify proteins. When radioactive isotopes are used, they can be detected by the radiation they emit (this is called radioisotope labeling).

Using nuclear properties • A technique similar to radioisotope labeling is radiometric dating: using the known half-life of an unstable element, one can calculate the time that has elapsed since a known isotopic level was present. The best-known example is radiocarbon dating, used to determine the age of carbonaceous materials. • Different forms of spectroscopy are based on the unique nuclear properties of specific isotopes, both more radioactive and more stable. For example, nuclear magnetic resonance (NMR) spectroscopy can only be used for isotopes with a non-zero nuclear spin. The most commonly used isotopes in NMR spectroscopy are 1H, 2D, 15N, 13C, and 31P. • Mössbauer spectroscopy is also based on nuclear transitions of certain isotopes, such as e.g. B. 57Fe. • Radionuclides also have important uses. The development of nuclear power and nuclear weapons requires relatively large amounts of specific isotopes. Nuclear medicine and radiation oncology each use radioisotopes for medical diagnosis and treatment.

Notes • Isotopes are nuclides that have the same number of protons; compare: • Isotones are nuclides that have the same number of neutrons. • Isobars are nuclides that have the same mass number, ie the sum of protons plus neutrons. • Nuclear isomers are different excited states of the same nuclear type. The transition from one isomer to another is accompanied by the emission or absorption of a gamma ray or by the process of internal conversion. Isomers are by definition isotopic and isobaric. (Not to be confused with chemical isomers.) • Isodiaphers are nuclides that have the same neutron excess, ie the number of neutrons minus the number of protons. • Bainbridge mass spectrometer

Literature [1] IUPAC (Connelly, NG; Damhus, T.; Hartshorn, RM; and Hutton, A.T.), Nomenclature of Inorganic Chemistry – IUPAC Recommendations 2005 (http://old.iupac.org/publications/books/rbook/ Red_Book_2005.pdf), Royal Society of Chemistry, 2005; IUPAC (McCleverty, J.A.; and Connelly, N.G.), Nomenclature of Inorganic Chemistry II. Recommendations 2000, Royal Society of Chemistry, 2001; IUPAC (Leigh, G.J.), Nomenclature of Inorganic Chemistry (1990 Recommendations), Blackwell Science, 1990; IUPAC, Nomenclature of Inorganic Chemistry, Second Edition (http://pac.iupac.org/publications/pac/pdf/1971/pdf/2801x0001.pdf), 1970; probably also in the first edition from 1958 [2] This notation seems to have been introduced in the second half of the 1930s, before that different notations were used, like Ne(22) for Neon-22 (1934) (http : // books . google.ca/ books?id=jkMcAQAAIAAJ& q=isotope& hl=en), Ne22 for Neon-22 (1935) (http:// books. google.ca/ books?id=7KQOAAAAIAAJ& q=neon-22 + Ne22& hl = en) or even Pb210 to Lead-210 (1933) (http://books.google.ca/books?id=HD7OAAAAMAAJ& q=isotope& hl=en). [4] Chopin, G.; Liljenzin, J. O. and Rydberg, J. (1995) Radiochemistry and Nuclear Chemistry (2nd ed.) Butterworth-Heinemann, pp. 3–5 [5] Others have also suggested the possibility of isotopes; for example., • •

Strömholm, Daniel and Svedberg, Theodor (1909) "Investigations into the chemistry of basic radioactive materials II". (Studies in the chemistry of radioactive elements, part 2), Journal of Inorganic Chemistry, 63: 197-206; see in particular page 206.

Alexander Thomas Cameron, Radiochemistry (London, England: J.M. Dent & Sons, 1910), p. 141. (Cameron also anticipated the displacement law.) [6] Scerri, Eric R. (2007) The Periodic Table Oxford University Press, pp. 176–179 ISBN 0195305736 [7] See:

Isotope

291 •

Kasimir Fajans (1913) "On a relation between the nature of a radioactive transformation and the electrochemical behavior of the relevant radio elements", Physikalische Zeitung, 14: 131-136. • Soddy promulgated his "law of displacement" in: . • Soddy worked out his law of displacement in: Soddy, Frederick (1913) “Radioactivity”, Annual Report of the Chemical Society, 10: 262–288. • Alexander Smith Russell (1888–1972) also published a displacement law: Russell, Alexander S. (1913) "The Periodic System and the Radium Elements", Chemical News and Journal of Industrial Science, 107: 49–52. [8] Soddy first used the word "isotope" in: [10] Scerri, Eric R. (2007) The Periodic Table, Oxford University Press, ISBN 0195305736, chap. 6, footnote 44 (p. 312) with a quote from Alexander Fleck, who is described as a former student of Soddy. [11] In his 1893 book, William T. Preyer also used the word "isotope" to denote similarities between elements. from p. 9 (http://books.google.com/books?id=8zDsAAAAMAAJ& pg=PA9) by William T. Preyer, The genetic system of the chemical elements (Berlin, Germany: R. Friedländer & Sohn, 1893): "The former I have called isotopes of elements for the sake of brevity, because they acquire the same place, viz. the same things, in each of the seven tribes." (For brevity I have called the first elements "isotopes" because they occupy the same place in each of the seven families [i.e. the columns of the periodic table], i.e. the same step [i.e. the row of the periodic table.] [In other words , each element in a given row of the periodic table has similar ("isotopic") chemical properties to the other elements in the same column of the periodic table. ]) [12] Origin of isotopic conceptions (http://www.nobelprize.org/nobel_prizes/ chemical/laureates/1921/soddy-lecture.html) Frederick Soddy, Nobel Prize Lecture [15] Mass Spectra and Isotopes (http://www.nobelprize.org/nobel_prizes/chemical/ laureates/ 1922/aston-lecture.html) Francis W. Aston, Nobel Prize Lecture 1922

External links • Nucleonica Nuclear Science Web Portal (http://www.nucleonica.com/) • Karlsruhe Nuclide Chart (http://www.nucleonica.com/wiki/index.php?title=Category: KNC) • National Nuclear Data Center (http://www.nndc.bnl.gov/) Portal to a vast collection of free NNDC data and analysis programs • National Isotope Development Center (http://isotopes.gov/) Coordination and management of isotope production, availability and distribution and reference information for the isotope community • Isotope Development and Production for Research and Applications (IDPRA) (http://science.energy.gov/np/research/idpra/) US Department of Energy Research and Development Isotope Production and Production Program • International Atomic Energy Agency (http://www.IAEA.org) Homepage of the International Atomic Energy Agency (IAEA), a United Nations (UN) agency • Atomic weights and composition Isotopic compositions per all elements (http://phys ics.nist.gov/cgi-bin/Compositions/ stand_alon e.pl?ele=&ascii=html&isotype=some) Static table, from NIST (National Institute of Standards and Technology) • Atomic weights, decay energies and half-lives of all isotopes (http:/ /atom.kaeri.re.kr/) • Exploring the Isotope Table (http://ie.lbl.gov/education/isotopes.htm) at LBNL • Research and information about isotopes. info/) isotope.info • Emergency Preparedness and Response: Radioactive Isotopes (http://www.bt.cdc.gov/radiation/isotopes/) from CDC (Centers for Disease Control and Prevention) • Table of Nuclides (http:// www.bt.cdc.gov/radiation/isotopes/) / www.nndc.bnl.gov/chart /) Interactive Table of Nuclei (National Nuclear Data Center) • Interactive Table of Nuclei, Isotopes and Periodicals (http://www .yoix.org/elements.html) • The Nuclide LIVEChart – IAEA (http://www-nds.iaea.org/livechart) with isotope data. • Isotope Annotated Bibliography (http://alsos.wlu.edu/adv_rst.aspx?keyword=isotope&creator=&title=& media=all&genre=all&disc=all&level=all&sortby=relevance&results=10&period=15) from the Alsos Digital Library for Nuclear Studies . Affairs

atomic number

292

Atomic number In chemistry and physics, the atomic number (also known as the proton number) is the number of protons in the atomic nucleus and is therefore identical to the charge number of the atomic nucleus. It is conventionally represented by the symbol Z. The atomic number uniquely identifies a chemical element. In a neutrally charged atom, the atomic number is also equal to the number of electrons. The atomic number Z should not be confused with the mass number A, which is the number of nucleons, the total number of protons and neutrons in the nucleus of an atom. The number of neutrons, N, is known as the number of neutrons in the atom; so A = Z + N (these quantities are always integers). Since protons and neutrons have approximately the same mass (and the mass of electrons is negligible for most purposes) and the mass defect of nucleon bonding is always small compared to nucleon mass, the atomic mass of any atom when expressed in unitary atomic mass units ( giving a quantity called "relative isotopic mass") is approximately (within 1%) equal to the integer A.

An explanation of the superscripts and subscripts seen in ordinal notation. The atomic number is the number of protons and thus also the total positive charge in the atomic nucleus.

Isotopes are atoms that have the same atomic number Z but different neutron numbers N and therefore different atomic masses. A little over three quarters of the Rutherford-Bohr model of the hydrogen atom (Z=1) or hydrogen-like ion are naturally occurring elements such as (Z>1). In this model, a key feature is that the mixture of photon energy (or frequency) isotopes (see monoisotopic electromagnetic radiation emitted (shown) when an electron jumps from one element) and the average isotopic mass of the orbital to another are proportional to the quadratic mathematician of the atomic charge (Z2). Henry Moseley's experimental measurement of this radiation for many isotopic mixtures of an element (called elements (from Z = 13 to 92) showed the results predicted by Bohr. Both relative atomic masses) in a clear notion of atomic number and Bohr's model were the scientific environment so given on earth determines credibility. Standard atomic weight of the element. Historically, these atomic weights of the elements (compared to hydrogen) were the quantities chemists could measure in the 19th century. The conventional symbol Z comes from the German word Zahl meaning number/digit/number, which before the modern synthesis of ideas in chemistry and physics simply denoted the numerical position of an element in the periodic table, a property that is more or less atomically determined weights. . , but not in all cases (see below). Only from 1915, with

atomic number

293

The suggestion and proof that this Z number was also the nuclear charge and a physical property of atoms brought the word atomic number and its English equivalent atomic number into common use.

History The Periodic Table and a Natural Number for Each Element Generally speaking, the existence or construction of a periodic table of elements creates an order for the elements. Such ordering is not necessarily numbering, but can be used to construct numbering per fiat (i.e. simply deciding that elements are given integers based on their position in the table, starting with hydrogen as "number one") . Dmitri Mendeleev claimed that he ordered his first periodic tables by atomic weight (weight 127.6). Weight 126.9).[1][2] This placement is consistent with the modern practice of ordering elements by the number of protons Z, but that number was neither known nor conjectured at the time. However, simple numbering based on position on the periodic table has never been entirely satisfactory. In addition to iodine and tellurium, the later Russian chemist Dmitri Mendeleev created other pairs of elements (such as argon and potassium, cobalt and nickel) in a periodic table of elements known to have near-identical or inverse atomic weights, sometimes in order numerically by them Atomic weight, however, they occasionally use chemicals that leave their position in the periodic table by chemical properties to contradict properties by weight. Violation of known physical properties. Another problem was that the gradual identification of more and more chemically similar and indistinguishable lanthanides, the number of which was uncertain, led to inconsistencies and uncertainties in the periodic numbering of the elements, at least starting with lutetium (element 71) (hafnium was not known at the time ). this time).

O modelo de Rutherford-Bohr and van den Broek

Ernest Rutherford's 1911 interpretation of the work in his laboratory identified the atomic nucleus and suggested that the number of charges in the gold nucleus (79 on the periodic table) was about 100.

In 1911, Ernest Rutherford presented a model of the atom in which a central nucleus contained most of the atomic mass and a positive charge which, in terms of electronic charge, would be approximately equal to half the atomic weight of the atom. Atom. , expressed in the number of hydrogen atoms. This central charge would therefore be about half the atomic weight (although it differs by almost 25% from the atomic number of gold (Z=79, A=197), the only element Rutherford conjectured). Despite Rutherford's estimate that gold had a central charge of about 100 (but it was element Z = 79 on the periodic table), Antonius van den Broek first officially proposed a month after Rutherford's article appeared that the central charge and the number of Electrons in an atom was exactly equal to its place in the periodic table (also known as element number, atomic number and symbolized Z). This turned out.

atomic number

294

Moseley's experiment in 1913 The experimental situation improved dramatically after the research of Henry Moseley in 1913.[3] Moseley, after discussing with Bohr that he was in the same laboratory (and that he had used the van den Broek hypothesis in his model of the Bohr atom), decided the van den Broek and Bohr theories -To test the hypothesis directly by checking that the lines The spectral lines emitted by excited atoms correspond to Bohr's theory that the frequency of the spectral lines is proportional to a measure of the square of Z. To do this, Moseley measured the wavelengths of the innermost photon transitions (K and L lines) produced by elements ranging from aluminum (Z=13) to gold (Z=79) used as a series of moving anode targets in an X-ray tube.[ 4] The square root of the frequency of these photons (X-rays) increased linearly from one target to the next. This led to the conclusion (Mosley's law) that the atomic number (with a unit shift to the K-lines in Moseley's work) corresponds very well to the calculated electric charge of the nucleus, i.e. the element number Z. Among other things, Moseley showed that the lanthanide series (from lanthanum up to and including lutetium) must have 15 members, neither less nor more, which was anything but self-evident in chemistry at the time.

Henry Moseley helped develop the concept of atomic number by showing experimentally (1913) that Van den Broek's 1911 hypothesis combined with Bohr's model predicted atomic X-ray emissions almost correctly.

The Proton and the Idea of Nuclear Electrons In 1915 it was not clear why nuclear charge was quantified in units of Z, now recognized as equal to element number. An old idea called the Prout hypothesis posited that all elements are made up of residues (or "protiles") of the lightest element, hydrogen, which in the Bohr-Rutherford model had a single electron and a nuclear charge of one. However, as early as 1907 Rutherford and Thomas Royds showed that alpha particles, which had a +2 charge, were the nuclei of helium atoms, which had four times the mass of hydrogen, not twice the mass of hydrogen. If Prout's hypothesis were true, something would have to neutralize some of the charge on the hydrogen nuclei in the nuclei of the heavier atoms. In 1917, Rutherford succeeded in creating hydrogen nuclei from a nuclear reaction between alpha particles and nitrogen gas, and he believed he had proved Prout's law. In 1920 he named the new heavy nuclear particles protons (alternative names are protons and protyles). It was immediately apparent from Moseley's work that the nuclei of heavy atoms have more than twice the mass that would be expected if they consisted of hydrogen nuclei, and hence a hypothesis for the neutralization of hydrogen was required. present in all heavy nuclei. A helium nucleus should consist of four protons plus two "core electrons" (bound electrons within the nucleus) to cancel out two of the charges. At the other end of the periodic table, a gold nucleus with a mass 197 times that of hydrogen was thought to have 118 core electrons in the nucleus to give it a residual charge of +79, consistent with its atomic number.

atomic number

The discovery of the neutron makes Z the number of protons. With Chadwick's discovery of the neutron in 1932, all consideration of nuclear electrons ended. A gold atom now contained 118 neutrons instead of 118 core electrons, and its positive charge now came entirely from containing 79 protons. After 1932, therefore, the atomic number Z of an element was considered identical to the number of protons in its nucleus.

The Symbol for Z The traditional symbol Z probably derives from the German word atomic number.[5] Before 1915, however, the word number (simply number) was used for the number assigned to an element on the periodic table.

Chemical Properties Each element has a specific set of chemical properties due to the number of electrons present in the neutral atom, which is Z (atomic number). The configuration of these electrons follows the principles of quantum mechanics. The number of electrons in each element's electron shells, especially in the outermost valence shell, is the main factor in determining its chemical bonding behavior. Therefore, only the atomic number determines the chemical properties of an element; and for this reason an element can be defined as consisting of any mixture of atoms with a certain atomic number.

New elements The search for new elements is often described with ordinal numbers. Elements with atomic numbers from 1 to 118 have been observed since 2010. New elements are synthesized by bombarding target atoms of heavy elements with ions, so that the sum of the atomic numbers of the target and the ions of the elements is equal to the atomic number of the element to be produced. In general, half-life decreases with increasing atomic number, although an "island of stability" can exist for undiscovered isotopes with a certain number of protons and neutrons.

References [1] The Periodic Table of the Elements (http://www.aip.org/history/curie/periodical.htm), American Institute of Physics [2] The Evolution of the Periodic Table (http://www.rsc.org/ chemsoc/visualelements/pages/history_ii.html), Chemsoc [3] Ordering Elements in the Periodic Table (http://www.rsc.org/Education/Teachers/Resources/periodictable/pre16/order.doc), Royal Chemical Society [4] Moseley article with illustrations (http://www.chemical.co.nz/henry_moseley_article.htm)101/atoms/faq/why-is-the-atomic-number-Z.shtml)

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half-life

296

Half-life Number of elapsed half-lives

Fraction Remaining Percentage remaining

100

(Video) The Difference Between Soldering Aluminum and Brazing Aluminum

12 .5

6 .25

3 .125

1.563

0,781

...

Norte

100/(2n)

/1 /2 /4 /8 /16 /32 /64 /128

/2n

The half-life (t½) is the time it takes for a quantity to fall to half its measured value at the beginning of the period. In physics it is usually used to describe some property of radioactive decay, but it can be used to describe any quantity that follows exponential decay. The original term, dating back to Ernest Rutherford's discovery of the principle in 1907, was "half-life", which was shortened to "half-life" in the early 1950s.[1] Half-life is used to describe a quantity that decays exponentially and is constant over the lifetime of the decaying quantity. It is a characteristic unit for the exponential decay equation. The term "half-life" can be used generically to refer to any period of time during which a quantity is halved, even if the decrease is not exponential. For a general introduction and description of exponential decay, see exponential decay. For a general introduction and description of non-exponential decay, see the rate law. The opposite of half-life is doubling time. The table on the right shows the reduction of an amount in relation to the number of half-lives elapsed.

half-life

297

Probabilistic Nature of Half-Life A half-life generally describes the decay of discrete entities, such as radioactive atoms, that have unstable nuclei. In this case, using the definition "Half-life is the time it takes for exactly half of the entities to decay" doesn't work. For example, if there is only one radioactive atom with a half-life of one second, there will be no "half atom" left after one second. There will be zero or one atom left, depending on whether that atom has decayed or not. Instead, the half-life is defined as a probability. It is the moment when the expected value of the number of decayed units is equal to half of the original number. For example, one could start with a single radioactive atom, wait for its half-life, and then see whether or not it has decayed. If this experiment is repeated, we see that on average it decays within half-life 50% of the time. The probability that a radioactive atom will decay during its half-life is 0.5; fifty%. In some experiments (e.g. the synthesis of a superheavy element) only one radioactive atom is actually produced at a time, the lifetime of which is measured individually. In this case, statistical analysis is required to infer the half-life. In other cases, very many identical radioactive atoms decay in the measured time interval. In this case, the law of large numbers ensures that the number of atoms actually decaying is approximately equal to the number of atoms expected to decay. In other words, with a large enough number of decaying atoms, the probabilistic aspects of the process can be neglected.

Simulating many identical atoms in radioactive decay, starting with 4 atoms per box (left) or 400 (right). The number at the top indicates how many half-lives have passed. Remember the law of large numbers: with more atoms, the overall decay is more regular and predictable.

There are several simple exercises that demonstrate probabilistic decay, such as tossing coins or running a statistical computer program.[2][3][4] For example, the image on the right is a simulation of many identical atoms undergoing radioactive decay. Note that after a half-life, due to random variations in the process, there aren't exactly half the atoms left, only approximately. However, with more atoms (right boxes), the overall decay is smoother and less random than with fewer atoms (left boxes), in accordance with the law of large numbers.

Half-life formulas for exponential decay An exponential decay process can be described by one of the following three equivalent formulas:

where • N0 is the initial amount of substance that will decompose (this amount can be measured in grams, moles, number of atoms, etc.), • N(t) is the amount that is left after a and has not yet decayed Time t, • t1/2 is the half-life of the diminishing magnitude, • τ is a positive number called the half-life of the diminishing magnitude, • λ is a positive number called the decay constant of the diminishing magnitude. the three parameters

, and λ are all directly related as follows:

half-life

298

where ln(2) is the natural logarithm of 2 (about 0.693). Click View to see a detailed derivation of the relationship between half-life, decay time, and decay constant. Start with the three equations.

We want to find a relationship between

, and λ, so that these three equations describe exactly the same exponential decay process.

Comparing the equations, we find the following condition:

Next we take the natural logarithm of each of these quantities.

Using the properties of logarithms, this simplifies to:

Since the natural logarithm of e is 1, we get:

Unfactor t and replace

, the end result is:

Connecting and manipulating these relationships, we get all of the following equivalent descriptions of exponential decay in terms of half-life:

Regardless of how it is written, we can enter the formula to get:

as expected (this is the definition of "initial value")

•

as expected (that's the definition of half-life)

•

, that is, the quantity approaches zero as t approaches infinity, as expected (the longer we wait, the less remains).

Decay through two or more processes Some quantities decay simultaneously through two exponential decay processes. The real half-life T1/2 can be related to the half-lives t1 and t2 that the quantity would have if each of the decomposition processes acted on its own:

For three or more processes, the analogous formula is:

For a proof of these formulas, see Exponential Decay# Decay by Two or More Processes.

half-life

299

Examples There is a half-life that describes every exponential decay process. For example: • Current flowing through an RC circuit or an RL circuit decays with a half-life of

respectively For this example, the term half-life could be used instead of "half-life", but they mean the same thing. • In a first-order chemical reaction, the half-life of the reactant is , where λ is the rate constant of the reaction. • In radioactive decay, the half-life is the length of time after which there is a 50% chance that an atom has undergone nuclear decay. It varies depending on the type of atom and isotope and is usually determined experimentally. See list of nuclides. The half-life of a species is the time it takes for the concentration of the substance to drop to half its initial value

Half-life of non-exponential decay The decay of many physical quantities is not exponential; for example the evaporation of water from a puddle or (often) the chemical reaction of a molecule. In these cases, half-life is defined as before: as the time it takes for half of the original amount to decay. However, unlike an exponential decay, the half-life depends on the initial quantity, and the future half-life changes over time as the quantity decreases. For example, the radioactive decay of carbon-14 is exponential with a half-life of 5730 years. A lot of carbon-14 decays to half its original amount after 5,730 years (on average), no matter how large or small the original amount is. After another 5,730 years, a quarter of the original will remain. On the other hand, the time it takes for a puddle to evaporate halfway depends on the depth of the puddle. Perhaps a puddle of a certain size will evaporate to half its original volume in a day. But on day two, there's no reason to expect a quarter of the puddle to remain; In fact, it will likely be a lot less. This is an example where half-life decreases over time. (For other non-exponential decays, it may increase.) The decay of a mixture of two or more materials, each decaying exponentially but with different half-lives, is non-exponential. Mathematically, the sum of two exponentials is not a single exponential. A common example of this situation is waste from nuclear power plants, which is a mixture of substances with very different half-lives. Consider a sample containing fast-decaying element A with a half-life of 1 second and slow-decaying element B with a half-life of 1 year. After a few seconds, after repeatedly halving the initial total number of atoms, almost all of the atoms of element A have decayed; but very few of the atoms of element B will have decayed since only a small fraction of the half-life has elapsed. Thus, the mixture as a whole does not break in half.

Half-life in biology and pharmacology The biological half-life or elimination half-life is the time it takes for a substance (drug, radioactive nuclide or other) to lose half of its pharmacological, physiological or radiological activity. In a medical context, half-life can also describe the time it takes for the concentration of a substance in the blood plasma to reach half of its steady-state value (the "plasma half-life"). The relationship between the biological half-life and the plasma half-life of a substance can be complex due to factors such as tissue accumulation, active metabolites, and receptor interactions.[] While a radioactive isotope follows what is known as the "first kinetic order," where the rate constant is a fixed number the removal of a substance from a living organism generally involves more complex chemical kinetics.For example, the biological half-life of water in a human is about 7 to 14 days, although it can be altered by your behavior.The biological half-life of cesium in humans is one to four months. That can be

The half-life is shortened by the addition of Prussian blue, which acts as a solid ion exchanger, taking up cesium and releasing potassium ions in the process.

References [1] John Ayto, "Words of the Twentieth Century" (1989), Cambridge University Press.

External links • Nucleonica.net (http://www.nucleonica.net), Nuclear Science Portal • Nucleonica.net (http://www.nucleonica.net/wiki/index.php/Help:Decay_Engine), Wiki: Decay Engine • Bucknell.edu (http://www.facstaff.bucknell.edu/mastascu/elessonshtml/SysDyn/SysDyn3TCBasic.htm), System Dynamics - Time Constants • Subotex.com (http://www.subotex.com/ SuboxoneTaperChart .aspx ), Elimination Half-Life of Blood Plasma Drugs - Simple Charting Tool

300

oxygen

301

oxygen oxygen O 8

nitrogen ← oxygen → fluorine ↑

O ↓ S oxygen in the periodic table aspect colorless gas; light blue liquid. Bubbles of oxygen rise in this photo of liquid oxygen.

General Properties of Oxygen Spectral Lines Name, Symbol, Number

oxygen, O, 8

pronunciation

/ˈɒksɨdʒən/ OK-si-jən

item category

diatomic nonmetal, chalcogen

group, period, block

16 (Chalkogene), 2, p.

standard atomic weight

15.999(4)

oxygen

302 electronic configuration

[Kante] 2s2 2p4 2, 6

discovery of history

Carl Wilhelm Scheele (1772)

named after

Antoine Lavoisier (1777) Physical Properties

Phase

Gas

density

(0 °C, 101,325 kPa) 1,429 g/l

liquid density in p.b.

1,141 g·cm−3

fusion point

54,36 K, -218,79 °C, -361,82 °F

boiling point

90,20 K, -182,95 °C, -297,31 °F

Critical point

154,59 K, 5,043 MPa

heat of fusion

(O2) 0.444 kJ·mol−1

heat of vaporization

(O2) 6.82 kJ·mol−1

molar heat capacity

(O2) 29.378 J mol−1 K−1 vapor pressure

P (Pa)

1 10 100 1 thousand 10 thousand 100 thousand

andT (K)

90 atomic properties

oxidation states

2, 1, −1, −2

electronegativity

3.44 (Pauling Scale)

Ionization energies (more)

1st: 1313.9 kJ mol-1 2nd: 3388.3 kJ mol-1 3rd: 5300.5 kJ mol-1

covalent ray

66±14:00

Radio Van der Waals

152 hours

oxygen

303 miscellaneous crystal structure

cubic

magnetic request

paramagnetic

thermal conductivity

26,58x10-3W·m−1·K−1

speed of sound

(Gas, 27 °C) 330 m·s-1

CAS registration number

7782-44-7 Most stable isotopes Main article: Oxygen isotopes

You are so

THE

Half-life DM SD (MeV) SD

99,76%

sixteen

0,039 %

16 17

0,201%

O is stable at 8 neutrons O is stable at 9 neutrons

Or is it stable with 10 neutrons

Oxygen is a chemical element with the symbol O and atomic number 8. Its name derives from the Greek roots ὀξύς (oxys) ("acid", literally "pungent", referring to the sour taste of acids) and -γόνος (-gοnos ) ("producer", lit. "producer"), because at the time of naming it was wrongly assumed that all acids in their composition require oxygen. In the usual bluish-white glow of an oxygen discharge tube. Temperature and pressure combine two atoms of the element to form dioxygen, a colorless, odorless, and tasteless diatomic gas with the formula O2. This substance is an important part of the atmosphere and necessary for most life on Earth. Oxygen belongs to the group of chalcogens in the periodic table and is a highly reactive nonmetallic element that readily forms compounds (especially oxides) with most elements except the noble gases helium and neon. Oxygen is a strong oxidizing agent, and only fluorine has greater electronegativity.[1] Oxygen is the third most abundant element by mass in the universe after hydrogen and helium[2] and the most abundant element by mass in the Earth's crust, accounting for nearly half the mass of the Earth's crust.[] Oxygen is chemically very strong. reactive. remain a free element in Earth's atmosphere without being constantly replenished by the photosynthetic activity of living organisms, which use the energy of sunlight to create elemental oxygen from water. Free elemental O 2 did not begin to accumulate in the atmosphere until about 2.5 billion years ago (see Great Oxygenation Event), about a billion years after these organisms first appeared.[3] Gaseous diatomic oxygen makes up 20.8% of the volume of air.[4] Oxygen makes up most of the mass of living organisms, since water is its main component (e.g. about two-thirds the mass of the human body[5]). Many major classes of organic molecules in living organisms, such as proteins, nucleic acids, carbohydrates, and fats, contain oxygen, as do the major inorganic compounds that make up animal shells, teeth, and bones. Elemental oxygen is produced by cyanobacteria, algae and plants and used by all complex living beings for cellular respiration. Oxygen is toxic to obligately anaerobic organisms, which were the first dominant organisms on Earth until O 2 began to accumulate in the atmosphere. Another form (allotrope) of oxygen, ozone (O

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3),

It strongly absorbs UVB radiation and consequently the high-altitude ozone layer helps protect the biosphere from ultraviolet radiation, but it is a pollutant near the surface where it is a by-product of smog. At altitudes even higher than low Earth orbit, atomic oxygen is a significant presence and a cause of spacecraft erosion.[6] Oxygen was discovered independently by Carl Wilhelm Scheele at Uppsala in or before 1773 and Joseph Priestley at Wiltshire in 1774, but Priestley is usually given priority because his work was published first. The name oxygen was coined in 1777 by Antoine Lavoisier,[] whose experiments with oxygen helped discredit the then-popular phlogiston theory of combustion and corrosion. Oxygen is produced industrially by fractional distillation of liquefied air, use of zeolites in the pressure cycle to concentrate oxygen in the air, electrolysis of water, and other means. Uses of elemental oxygen include the manufacture of steel, plastics, and textiles, brazing, welding, and cutting of steels and other metals, rocket fuel, oxygen therapy, and life support systems in aircraft, submarines, space travel, and scuba diving.

Properties Structure At normal temperature and pressure, oxygen is a colorless and odorless gas with the molecular formula O 2 in which the two oxygen atoms are chemically bonded to each other in a spin triplet electron configuration. This bond has a bond order of two and is often described simply as a double bond [7] or as a combination of one two-electron bond and two three-electron bonds. [] The triplet oxygen (not to be confused with ozone, O 3 ) is the ground state of the molecule O oxygen O2. [] 2 molecules. The electronic configuration of the molecule consists of two unpaired electrons occupying two degenerate molecular orbitals.[8] These orbitals are classified as antibonding (weakening the bonding order from three to two), so the oxygen diatomic bond is weaker than the nitrogen diatomic triple bond, in which all bonding molecular orbitals are filled but some orbitals are filled. Antibonding orbitals are not filled. .[] In the normal triplet form, O 2 molecules are paramagnetic. That is, they form a magnet in the presence of a magnetic field due to the spin magnetic moments of the unpaired electrons in the molecule and the exchange of negative energy between neighboring O[9]2 molecules. Liquid oxygen is so attracted to a magnet that in laboratory demonstrations a liquid oxygen bridge can support its own weight between the poles of a strong magnet.[10][11]

A stream of liquid oxygen is deflected by a magnetic field, illustrating its paramagnetic property.

Singlet oxygen is a name for several high-energy O 2 molecular species in which all electron spins are paired. It is much more reactive with common organic molecules than molecular oxygen per se. In nature, singlet oxygen is commonly formed from water during photosynthesis using energy from sunlight.[12] It is also produced in the troposphere by photolysis of ozone by short-wavelength light[] and by the immune system as a source of active oxygen.[] Carotenoids play a role in photosynthetic organisms (and possibly animals). Role in absorbing energy from singlet oxygen and converting it to the unexcited ground state before it can cause tissue damage.[13]

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Allotrope

Ozone is a rare gas on earth, found mainly in the stratosphere.

The common allotrope of elemental oxygen on Earth is called dioxygen O −1 [14] 2 . It has a bond length of 121 pm and a bond energy of 498 kJ mol. This is the form used by complex life forms such as animals in cellular respiration (see Biological Role) and the form that makes up most of the Earth's atmosphere (see Occurrence). Other aspects of O 2 are covered in the rest of this article.

Trioxygen (O 3 ) is commonly known as ozone and is a highly reactive oxygen allotrope that damages lung tissue. Ozone is formed in the upper atmosphere when O 2 combines with atomic oxygen produced by O[] 2 decomposition by ultraviolet (UV) radiation. Because ozone is highly absorbed in the ultraviolet region of the spectrum, the ozone layer in the upper atmosphere acts as a radiation shield for the planet. .[] The metastable molecule tetraoxygen (O[][]4) was discovered in 2001 and is believed to exist in one of the six phases of solid oxygen. In 2006 it was shown that this phase, formed by pressurizing O 2 to 20 GPa, is in fact a rhombohedral cluster of O[15] 8 . This cluster has the potential to be a much more powerful oxidizer than O 2 or O [ ] [ ] 3 and can therefore be used as rocket fuel. A metallic phase was discovered in 1990 when solid oxygen was subjected to pressures in excess of 96 GPa[16] and in 1998 this phase was shown to become superconducting at very low temperatures.[17]

Physical Properties Oxygen is more soluble in water than nitrogen. Water in equilibrium with air contains about 1 dissolved O 2 molecule for every 2 N 2 molecules, compared to an atmospheric ratio of about 1:4. The solubility of oxygen in water is temperature dependent, with about twice as much dissolving at 0 °C (14.6 mg L-1) as at 20 °C (7.6 mg L-1).[18] [19] At 25 °C and 1 standard atmosphere (101.3 kPa) of air, fresh water contains about 6.04 milliliters (mL) of oxygen per liter, while seawater contains about 4.95 mL per liter.[twenty] At 5 °C, the Solubility increases to 9.0 ml (50% more than at 25°C) per liter of water and 7.2 ml (45% more) per liter of seawater. Oxygen condenses at 90.20 K (−182.95 °C, −297.31 °F) and freezes at 54.36 K (−218.79 °C, −361.82 °F).[21 ] Both liquid as well as solid O 2 are transparent substances with light sky-blue color caused by absorption in red (as opposed to sky-blue, due to Rayleigh scattering of blue light). The high-purity liquid O[22]2 is usually obtained by the fractional distillation of liquefied air. Liquid oxygen can also be produced by condensing air using liquid nitrogen as a refrigerant. It is a highly reactive substance and must be separated from combustible materials.[23]

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Isotopes and Stellar Origin Natural oxygen consists of three stable isotopes, 16O, 17O, and 18O, with 16O being the most abundant (99.762% natural abundance).[] Most 16O is synthesized at the end of the fusion process. in massive stars, but part is produced in the neon burning process. 14N (abundant from CNO combustion) traps a 4He nucleus, making 18O common in helium-rich regions of evolved massive stars.[] Fourteen radioisotopes have been characterized. The most stable are at the end of a massive star's life, 16O is concentrated in 15O with a half-life of 122.24 seconds and 14O with a half-life of the O layer, 17O in the H layer and 18O at 70.606 seconds. [ ] All remaining radioactive isotopes have a He shell. Half-lives less than 27 s and most of these have half-lives less than 83 milliseconds. The common mode for isotopes heavier than 18O is beta decay to produce fluorine.[]

Occurrence The ten most common elements in the Milky Way estimated spectroscopically[] Z

Element

Mass fraction in parts per million

hydrogen

739,000 71 × oxygen mass (red bar)

Helium

240,000 23 × oxygen mass (red bar)

oxygen

10.400

Money

4.600

10 Neon

1.340

26 Hierro

1.090

nitrogen

960

14 silicon

650

12 Magnesium

580

16 Sulfur

440

Oxygen is the most abundant chemical element by mass in the biosphere, air, sea and land on earth. Oxygen is the third most abundant chemical element in the universe after hydrogen and helium.[2] About 0.9% of the sun's mass is oxygen.[4] Oxygen makes up 49.2% of the mass of the earth's crust[] and is the main component of the world's oceans (88.8% by mass).[4] Oxygen gas is the second most abundant component of the Earth's atmosphere, occupying 20.8% of its volume and 23.1% of its mass (about 1015 tons).[4][24][25] Earth is unusual among planets in the solar system for having such a high concentration of oxygen gas in its atmosphere: Mars (with 0.1% O 2 by volume) and Venus have much lower concentrations. However, the O 2 surrounding these other planets is only produced by ultraviolet radiation striking oxygen-containing molecules such as carbon dioxide.

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The unusually high concentration of gaseous oxygen on Earth is a result of the oxygen cycle. This biogeochemical cycle describes the movement of oxygen within and between its three main reservoirs on Earth: atmosphere, biosphere, and lithosphere. The main driver of the oxygen cycle is photosynthesis, which is responsible for the modern earth's atmosphere. Photosynthesis releases oxygen into the atmosphere, while respiration and decomposition remove it from the atmosphere. At the current equilibrium, production and consumption occur at the same rate of about 1/2,000 of all atmospheric oxygen per year. Free oxygen is also found in dissolved form in the world's waters. The greater solubility of O 2 at lower temperatures (see Physical Properties) has important implications for ocean life, since the polar oceans support a much higher density of life due to their higher oxygen content.[26] Water contaminated with plant nutrients such as nitrates or phosphates can stimulate algal growth through a process called eutrophication, and the breakdown of these organisms and other biomaterials can reduce O 2 levels in eutrophic waters. Scientists assess this aspect of water quality by measuring the water's biochemical demand for oxygen, or the amount of O[27]2 needed to restore normal levels.

Cold water retains more dissolved O2.

Biological function of O2 photosynthesis and respiration In nature, free oxygen is produced by light-driven water splitting during oxygenic photosynthesis. According to some estimates, green algae and cyanobacteria in marine environments provide about 70% of the free oxygen produced on Earth, with the rest being produced by terrestrial plants.[28] Other estimates of the ocean's contribution to atmospheric oxygen are higher, while some estimates are lower, suggesting that the oceans produce about 45% of Earth's atmospheric oxygen each year.[29] A simplified general formula for photosynthesis is:[30]

Photosynthesis splits water to release O 2 and binds CO 2 into sugars in what is known as the Calvin cycle.

6 CO2 + 6 H 2O + Fotones → C 6H 12O 6+ 6 O 2

or simply

Carbon dioxide + water + sunlight → glucose + dioxygen Photolytic oxygen evolution occurs in the thylakoid membranes of photosynthetic organisms and requires the energy of four photons.[31] Many steps are involved, but the result is the formation of a proton gradient across the thylakoid membrane, which is used to synthesize ATP through photophosphorylation.[32] The O[33]2 remaining after the oxidation of the water molecule is released into the atmosphere.

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Molecular oxygen, O 2 , is essential for cellular respiration in all aerobic organisms. Oxygen is used in mitochondria to help form adenosine triphosphate (ATP) during oxidative phosphorylation. The aerobic respiratory response is essentially the reverse of photosynthesis and is simplified as: C 6H 12O 6+ 6 O 2 → 6 CO + 6 H 2 −1 2O + 2880 kJ mol In vertebrates, O 2 diffuses through the membranes of the lungs and in red ones blood cells. Hemoglobin binds to O[] 2 and changes color from blue-red to bright red (CO 2 is released from another part of hemoglobin by the Bohr effect). Other animals use hemocyanin (molluscs and some arthropods) or hemerythrin (spiders and lobsters).[24] A liter of blood can dissolve 200 cm3 O[24] 2 . Reactive oxygen species, such as superoxide ions (O−2) and hydrogen peroxide (H 2O [24] 2), are dangerous byproducts of oxygen consumption in organisms. . . However, parts of the immune system of higher organisms produce peroxide, superoxide and singlet oxygen to destroy invading microbes. Reactive oxygen species also play an important role in the hypersensitive response of plants to pathogen attack.[32] At rest, an adult human breathes in 1.8 to 2.4 grams of oxygen per minute.[34] This corresponds to more than 6 billion tons of oxygen that mankind breathes in every year.[35]

Content in the body Partial pressure of oxygen in the human body (PO2) Unit

kPa

alveolar lung gas pressures

Arterial oxygenation Venous blood gases

[36]

14.2

mmHg 107

[36]

-13

[37]

-100

[36]

4.0

[38]

[36]

-5,3

[38]

-40

The partial pressure of free oxygen in the body of a living vertebrate organism is greatest in the respiratory system and decreases along each arterial system, peripheral tissues and venous system. The partial pressure is the pressure that oxygen would have if it alone occupied the volume.[39]

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accumulates in the atmosphere

Accumulation of O 2 in the Earth's atmosphere: 1) O 2 is not produced; 2) O 2 produced but absorbed in oceans and deep-sea rocks; 3) O 2 begins to leave the oceans as a gas but is absorbed by the Earth's surface and forms

ozone layer; 4–5) 2 sinks and gas builds up

Free oxygen gas was almost non-existent in the Earth's atmosphere prior to the evolution of archaea and photosynthetic bacteria, probably about 3.5 billion years ago. Free oxygen first appeared in significant quantities during the Paleoproterozoic (2.5–1.6 billion years ago). During the first billion years, free oxygen produced by these organisms combined with dissolved iron in the oceans to form iron ribbon formations. When these oxygen sinks became saturated, free oxygen began to outgas from the oceans 2.7 billion years ago, reaching 10% of its present level about 1.7 billion years ago.[]

The presence of large amounts of free and dissolved oxygen in the oceans and atmosphere may have driven most living anaerobic organisms to extinction during the great oxygen event (oxygen catastrophe) about 2.4 billion years ago. However, cellular respiration using O 2 allows aerobic organisms to produce much more ATP than anaerobic organisms, helping the former to dominate the Earth's biosphere. [] Photosynthesis and cellular respiration of O 2 enabled the evolution of eukaryotic cells and eventually complex multicellular organisms, plants, and animals. The concentrations varied between 15 and 30% by volume. Towards the end of the Carboniferous period (about 300 million years ago), atmospheric O[] 2 levels reached a maximum of 35% by volume, which may have contributed to the large sizes of insects and amphibians at that time.[ ] Human activities, including . Burning 7 billion tons of fossil fuels per year has very little impact on the amount of free oxygen in the atmosphere.[9] At the current rate of photosynthesis, it would take about 2000 years to regenerate all the O[40] 2 in the current atmosphere.

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History Early Experiments One of the earliest known experiments on the relationship between combustion and air was carried out by the 2nd century BC Greek writer. carried out via mechanics. C., Philo of Byzantium. In his work Pneumatica, Philo observed that by inverting a vessel over a lit candle and filling the neck of the vessel with water, some of the water would rise up the neck.[41] Philo wrongly assumed that part of the air in the vessel had been transformed into the classical element fire and was therefore able to escape through the pores of the glass. Many centuries later, Leonardo da Vinci built on Philo's work by noting that some of the air is consumed during combustion and respiration.[42] In the late 17th century Robert Boyle showed that air is necessary for combustion. The English chemist John Mayow (1641–1679) improved on this work by showing that fire requires only a portion of air, which he called Spiritus nitroaereus, or simply Nitroaereus.[] In one experiment, he discovered that putting a mouse or a lit candle A closed container vessel above water allowed the water to rise and replace one fourteenth of the air volume before the subjects were extinguished. [] From this he concluded that Nitroaereus is consumed in both respiration and combustion. Philo's experiment later inspired Mayow's observation that antimony gained weight when heated, and the researchers concluded as much. that the Nitroaereus must have connected to it. [] He also thought that the lungs separate the nitroaereus from the air and direct it into the blood, and that animal heat and muscular movement result from the reaction of the nitroaereus with certain substances in the body. [] Accounts of these and other experiments and ideas were published in his work Tractatus duo in the treatise De respiratione in 1668.[]

Phlogiston theory Robert Hooke, Ole Borch, Mikhail Lomonosov, and Pierre Bayen (fr) produced oxygen in experiments in the 17th and 18th centuries, but none of them recognized it as a chemical element.[18] This may be due in part to the dominance of the combustion and corrosion philosophy known as the phlogiston theory, which was the preferred explanation of these processes at the time. The phlogiston theory, proposed by the German alchemist J.J. Becher in 1667 and modified by the chemist Georg Ernst Stahl in 1731,[] states that all combustible materials consist of two parts. A part, called phlogiston, came out when the substance containing it was burned, while the dephlogistic part was considered its true form or calx.[42] It was believed that highly combustible materials that leave little residue, such as wood or charcoal, are mainly made from phlogiston. while non-combustible substances that corrode, such as iron, contained very little. Air played no part in the phlogiston theory, nor were early quantitative experiments conducted to test the idea; Instead, it was based on observations of what happens when something burns that most ordinary objects seem to get lighter and lose something in the process.[42] That a substance like wood actually increased in total weight as it burned was obscured by the buoyancy of the gaseous products of combustion. In fact, one of the Stahls helped develop and popularize the phlogiston theory.

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The first clues that the phlogiston theory was wrong were that metals also gain weight through oxidation (when they supposedly lose phlogiston).

Discovery Oxygen was first discovered by Swedish pharmacist Carl Wilhelm Scheele. He produced gaseous oxygen around 1772 by heating mercuric oxide and various nitrates.[4][42] Scheele called the gas "air of fire" because he was the only known proponent of combustion, and he wrote an account of this discovery in a manuscript entitled A Treatise Concerning Air and Fire, which he sent to his publisher in 1775 and not until 1777 published.[43]

Carl Wilhelm Scheele was ahead of Priestley in the discovery but later published it.

Joseph Priestley is often given priority in the discovery.

Meanwhile, on August 1, 1774, an experiment by British clergyman Joseph Priestley concentrated sunlight on mercuric oxide (HgO) in a glass tube, releasing a gas he called "dephlogisticated air". He observed that candles glowed brighter in the gas and that a mouse was more active and lived longer while breathing it. After inhaling the gas himself, he wrote: "The feeling in my lungs was not much different from ordinary air, but I imagined that for some time afterwards my chest seemed particularly light and calm."[18] Priestley published his results in 1775. in an article entitled "An Account of Further Discoveries in the Air" contained in the second volume of his book entitled "Experiments and Observations on Various Kinds of Air". Because he published his findings first, Priestley is usually given discovery priority.

Renowned French chemist Antoine Laurent Lavoisier later claimed to have independently discovered the new substance. However, Priestley visited Lavoisier in October 1774 and told him about his experiment and how it released the new gas. Scheele also sent a letter to Lavoisier on September 30, 1774, describing his own discovery of the previously unknown substance, but Lavoisier never confirmed that he had received it (a copy of the letter was found in Scheele's possession after his death).

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Lavoisier's contribution What Lavoisier arguably did (although this was controversial at the time) was to perform the first proper quantitative experiments on oxidation and to provide the first correct explanation of how combustion works.[4] He used these and similar experiments, all beginning in 1774, to discredit the phlogiston theory and to prove that the substance discovered by Priestley and Scheele was a chemical element.

Antoine Lavoisier discredited the phlogiston theory.

In one experiment, Lavoisier observed that there was no general increase in weight when tin and air were heated in a closed vessel.[4] He noticed air being sucked in when the container was opened, indicating that some of the trapped air had been consumed. He also noted that the weight of the can had increased and that this increase in weight was equal to the weight of the air flowing back. This and other combustion experiments were documented in his book Sur la combust en général, published in 1777. [4] In this work he demonstrated that air is a mixture of two gases; 'vital air', essential for combustion and respiration, and whip (gr. ἄζωτον "lifeless"), which was also not maintained. Scourge later became nitrogen in English, although it retained the name in French and several other European languages.[4]

Lavoisier in 1777 changed the name "living air" to Oxygène from the Greek roots ὀξύς (oxys) (acid, literally "pungent", from the taste of acids) and -γενής (-genēs) (producer, lit that oxygen is a component of all acids. [] Chemists (particularly Sir Humphry Davy in 1812) eventually found that Lavoisier was wrong on this point (indeed hydrogen forms the basis of the chemistry of acids), but by then it was too late; took the name. Oxygen made its way into the English language despite opposition from English scientists and the fact that the Englishman Priestley was the first to isolate and write about the gas. This is partly due to a poem praising the gas entitled "Oxygen" in the popular book The Botanic Garden (1791) by Erasmus Darwin, Charles Darwin's grandfather.[43]

Later history John Dalton's original atomic hypothesis assumed that all elements were monatomic and that atoms in compounds usually have the simplest atomic proportions to one another. For example, Dalton assumed the formula for water to be HO and gave the atomic mass of oxygen as eight times that of hydrogen, rather than the modern value of about 16.[45] In 1805, Joseph Louis Gay-Lussac and Alexander von Humboldt showed that water consists of two volumes of hydrogen and one volume of oxygen; and in 1811 Amedeo Avogadro arrived at the correct interpretation of the composition of water based on what is now called Avogadro's law and the assumption of diatomic elementary molecules. In the late 19th century, scientists realized that air could be liquefied and its components isolated by compressing and cooling it. Using a cascade method, Swiss chemist and physicist Raoul Pierre Pictet Robert H. Goddard and liquid oxygen gasoline vaporized liquid sulfur dioxide to liquefy carbon dioxide, which in turn vaporized to cool the gaseous oxygen enough to liquefy it. He sent a telegram on December 22, 1877 to the French Academy of Sciences in Paris announcing his discovery of liquid oxygen.[] Just two days later, French physicist Louis Paul Cailletet announced his own method of liquefying molecular oxygen .[] Few drops of liquid were produced in each case, so a meaningful analysis could not be performed.

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accomplished. Oxygen was first liquefied in the steady state on March 29, 1883 by Polish scientists at Jagiellonian University, Zygmunt Wróblewski and Karol Olszewski.[48] In 1891, the Scottish chemist James Dewar managed to produce enough liquid oxygen for research.[9] The first commercially viable process for producing liquid oxygen was independently developed in 1895 by German engineer Carl von Linde and British engineer William Hampson. The two men lowered the temperature of the air until it liquefied, then distilled the component gases by boiling and trapping them one at a time. [] Later, in 1901, oxyfuel welding was first demonstrated by burning a mixture of acetylene and compressed O[] 2 . This method of welding and cutting metal later became common. In 1923, American scientist Robert H. Goddard was the first to develop a rocket engine that burned liquid fuel; The engine used gasoline as a fuel and liquid oxygen as an oxidizer. Goddard successfully flew a small 180-foot (56 m) liquid-fueled rocket at 60 mph (97 km/h) from Auburn, Massachusetts, USA, on March 16, 1926.[49]

Industrial Production Two main methods are used to extract 100 million tons of O[43] 2 from the air annually for industrial purposes. The most common method is to fractionally distill the liquefied air into its various components, with N 2 distilling as a vapor while O[43] 2 remains as a liquid. The other main method of producing O 2 gas is to pass a stream of clean, dry air through a bed of two identical zeolite molecular sieves that absorb nitrogen and provide a gas stream containing between 90% and 93% O [43 ] 2 Simultaneously, nitrogen gas is released from the other bed of nitrogen-saturated zeolites, reducing the operating pressure of the chamber and diverting some of the oxygen gas from the producing bed through it in the opposite direction to the flow. After a defined cycle time, the operation of the two beds is switched so that a continuous supply of gaseous oxygen can be pumped through a pipeline. This is known as pressure swing adsorption. Gaseous oxygen is increasingly being obtained by these non-cryogenic technologies (see also related vacuum swing adsorption).[50]

Hofmann electrolyser for the electrolysis of water.

Oxygen gas can also be produced by the electrolysis of water into molecular oxygen and hydrogen. Direct current must be used: when alternating current is used, the gases in each limb consist of hydrogen and oxygen in an explosive ratio of 2:1. Contrary to popular belief, the 2:1 ratio observed in DC electrolysis of acidified water does not prove that the molecular formula of water is H2O unless certain assumptions are made about the molecular formulas of hydrogen and oxygen. a similar

The method is the electrocatalytic evolution of O 2 from oxides and oxo acids. Chemical catalysts can also be used, such as in chemical oxygen generators or oxygen sails used as part of submarine life support equipment, and are still standard equipment on commercial aircraft in the event of depressurization emergencies. Another air separation technology involves dissolving air through zirconia-based ceramic membranes by high pressure or electric current to produce nearly pure O[27]2 gas.

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In bulk, the price of liquid oxygen was about $0.21/kg in 2001.[51] Since the main cost of production is the cost of energy to liquefy the air, the cost of production will change as the cost of energy changes. For economic reasons, oxygen is usually transported in bulk as a liquid in specially insulated tankers, since one liter of liquefied oxygen at atmospheric pressure and 20 °C (68 °F) is equivalent to 840 liters of gaseous oxygen.[43] These tanks are used to refill liquid oxygen storage tanks outside of hospitals and other facilities that require large volumes of pure oxygen gas. The liquid oxygen passes through heat exchangers that convert the cryogenic liquid to a gas before entering the building. Oxygen is also stored and transported in smaller cylinders that contain the compressed gas; a shape useful in certain portable medical applications and in oxy-fuel welding and cutting.[43]

Medical Applications The absorption of O 2 from the air is the main purpose of respiration, which is why supplemental oxygen is used in medicine. The treatment not only increases the oxygen levels in the patient's blood, but also has the side effect of reducing resistance to blood flow in many types of diseased lungs, thereby reducing the heart's workload. Oxygen therapy is used to treat emphysema, pneumonia, some heart diseases (congestive heart failure), some diseases that cause increased pressure in the pulmonary artery, and any disease that affects the body's ability to take up and use gaseous oxygen. [52]

An oxygen concentrator in the home of an emphysema patient

Treatments are flexible enough to be used in hospitals, in the patient's home, or increasingly with portable devices. Oxygen tents were once commonly used for oxygen supplementation, but have now been largely superseded by the use of oxygen masks or nasal cannulas.[]

Hyperbaric (high pressure) medicine uses special oxygen chambers to increase the partial pressure of O[] 2 around the patient and, if necessary, the medical staff. Carbon monoxide poisoning, gas gangrene, and decompression sickness (the "wrinkles") are sometimes treated with these devices.[53] The increased concentration of O[54][]2 in the lungs helps displace carbon monoxide from the heme group of hemoglobin. Gaseous oxygen is toxic to the anaerobic bacteria that cause gas gangrene, so increasing their partial pressure helps kill them.[55][56] Decompression sickness occurs in divers who decompress too quickly after a dive, resulting in the formation of inert gas bubbles, mainly nitrogen and helium, in the blood. Increasing the O[52][57][58]2 pressure as quickly as possible is part of the treatment. Oxygen is also used clinically for patients requiring mechanical ventilation, usually at concentrations greater than 21% in room air.

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Life Support and Recreational Use A notable application of O 2 as a low-pressure breathing gas is in modern space suits, which surround the occupants' bodies with pressurized air. These devices use near-pure oxygen at approximately one-third normal pressure, resulting in a normal partial blood pressure of O[][] 2 . This compromise between higher oxygen concentration and lower pressure is necessary to keep spacesuits flexible. Recreational divers and scuba divers also rely on artificially administered O 2 , but more commonly they use atmospheric pressure and/or air-oxygen mixtures. The use of pure or near-pure O 2 in diving at pressures above sea level is generally limited to the use of rebreather, decompression, or emergency treatment at relatively shallow depths (~6 meters deep or less). [][] Deeper diving requires significant dilution of O[] 2 with other gases such as nitrogen or helium to prevent oxygen toxicity.

In space suits, pure O 2 is used at low pressure.

People who climb mountains or fly in non-pressurized flat-wing aircraft sometimes have extra cabin O[59] 2. supplies. The sudden drop in cabin pressure activates the chemical oxygen generators above each seat, causing the oxygen masks to drop. Donning the masks "to initiate the flow of oxygen," as required by cabin safety procedures, forces sodium chlorate iron filings into the canister.[27] The exothermic reaction then creates a constant flow of oxygen gas. Oxygen, believed to be a mild euphoric, has a history of recreational use in oxygen bars and in sports. Oxygen bars are establishments found in Japan, California, and Las Vegas, Nevada since the late 1990s that offer above-normal exposure to O[] 2 for a fee. Professional athletes, particularly in football, also sometimes go off the field between games to wear oxygen masks to boost performance. The pharmacological effect is questionable; a placebo effect is a more likely explanation. [] Available studies demonstrate the enhanced performance of O[60]2-enriched blends only when inhaled during aerobic exercise. Other recreational uses where the gas is not inhaled include pyrotechnic uses, such as the five-second ignition of George Goble's barbecue grills.

The industrial smelting of iron ore into steel consumes 55% of the oxygen produced commercially.[27] In this process, O 2 is injected into the molten iron through a high-pressure lance, removing sulfur impurities and excess carbon as the corresponding oxides SO 2 and CO 2 . The reactions are exothermic, so the temperature rises to 1,700 °C [27] Another 25% of the commercially produced oxygen is used by the chemical industry.[27] Ethylene is reacted with O

Most commercially produced O 2 is used to smelt iron into steel.

oxygen to produce ethylene oxide, which in turn is converted to ethylene glycol; the primary raw material used to manufacture a range of products including antifreeze and polyester polymers (the precursors to many plastics and fabrics).[27] two

Most of the remaining 20% of commercially produced oxygen is used in medical applications, metal cutting and welding, as an oxidizer in rocket fuel, and water treatment.[27] Oxygen is used in oxyfuel welding, which burns acetylene with O 2 to produce a very hot flame. Metal up to 60 cm thick is first heated with a small acetylene-oxygen flame and then quickly sheared off with a large O2 jet [62] 2. Larger rockets use liquid oxygen as an oxidant, which is mixed with fuel and ignited for propulsion. [citation required]

Paleoclimatologists measure the ratio of oxygen-18 to oxygen-16 in the shells and skeletons of marine organisms to determine what the climate was like millions of years ago (see oxygen isotope ratio cycle). Seawater molecules, which contain the lighter isotope oxygen-16, evaporate slightly faster than water molecules, which contain the heavier 12% oxygen-18; this disparity increases at lower temperatures.[63] During times of lower global temperatures, snow and rain from this evaporated water tend to have more oxygen-16, and remaining seawater tends to have more oxygen-18. Marine organisms incorporate more oxygen-18 into their skeletons and shells in the face of 18O after 500 million years of climate change than in a warmer climate.[63] Paleoclimatologists also measure this connection directly in water molecules from ice samples several hundred thousand years old. Planetary geologists have measured different oxygen isotopic abundances in samples from Earth, the Moon, Mars, and meteorites, but have long been unable to obtain reference values for isotopic ratios in the Sun that are believed to be the same as those of the Sun as the the primeval sun. Fog. However, analysis of a silicon wafer exposed to the solar wind in space and brought back by the crashed Genesis spacecraft has shown that the sun has a higher percentage of oxygen-16 than Earth. The measurement suggests that an unknown process depleted the solar disk's oxygen-16 of protoplanetary material before the dust grains that formed Earth merged.[64] Oxygen has two spectrophotometric absorption bands with peaks at wavelengths of 687 and 760 nm. Some remote sensing scientists have proposed using irradiance measurements from tree canopies in these areas to characterize the health status of plants from a satellite platform.[65] This approach exploits the fact that in these bands it is possible to distinguish the reflection of vegetation from its fluorescence, which is much weaker. The measurement is technically difficult due to the low signal-to-noise ratio and the physical structure of the vegetation; However, it has been proposed as a possible method for monitoring the carbon cycle from satellites on a global scale.

316

oxygen

317

Compounds The oxidation state of oxygen is -2 in almost all known oxygen compounds. The -1 oxidation state is found in some compounds such as peroxides.[66] Oxygen-containing compounds in other oxidation states are very rare: -1/2 (superoxides), -1/3 (ozonides), 0 (elemental acid, hypofluorinated), +1/2 (dioxygenyl), +1 (dioxygen difluoride), and +2 (oxygen difluoride).

Oxides and other inorganic compounds Water (H 2 O) is the most well-known combination of oxygen and hydrogen oxide. Hydrogen atoms are covalently bonded to oxygen in a water molecule, but also have an additional attraction (ca. 23.3 kJ mol-1 per hydrogen atom) for an adjacent oxygen atom in a separate molecule.[ 67] These hydrogen bonds between water molecules hold them for about 15 % closer together than would be expected in a simple liquid with only van der Waals forces.[68][69]

Oxides such as iron oxide or rust are formed when oxygen combines with other elements.

Water (H 2 O) is the best known oxygen

composed.

Due to its electronegativity, oxygen forms chemical bonds with almost all other elements to form the corresponding oxides at elevated temperatures. However, some elements readily form oxides under normal temperature and pressure conditions; the oxidation of iron is an example. The surface of metals such as aluminum and titanium oxidizes in the presence of air and is covered by a thin oxide film that passivates the metal and retards corrosion. Some of the transition metal oxides occur naturally as non-stoichiometric compounds, with slightly less metal than the chemical formula would indicate. For example, natural FeO (wustite) is actually written as Fe[70] 1−xO, where x is usually about 0.05.

Oxygen as a compound is present in the atmosphere in trace amounts in the form of carbon dioxide (CO 2 ). The rocks of the earth's crust mainly consist of silicon oxides (silicic acid SiO 2, present in granite and sand), aluminum (aluminium oxide Al 2O 3, in bauxite and corundum), iron (ferric oxide Fe 2O 3, in hematite and rust) and calcium carbonate (in limestone). The rest of the earth's crust also consists of oxygen compounds, in particular various complex silicates (in silicate minerals). The Earth's mantle, much larger than the Earth's crust, is composed largely of silicates of magnesium and iron. Water-soluble silicates in the form of Na 4SiO 4 , Na 2SiO 3 and Na 2Si 2O [71] 5 are used as detergents and adhesives.

oxygen

318

Oxygen also acts as a ligand for transition metals, forming metal-O bonds [72] 2 with the iridium atom in the Vaska complex, with platinum in PtF [73] 6 and with the iron center of the heme group of hemoglobin.

Organic Compounds and Biomolecules The major classes of organic compounds containing oxygen include (where "R" is an organic group): alcohols (R-OH); ether (R-O-R); ketones (R-CO-R); aldehydes (R-CO-H); carboxylic acids (R-COOH); ester (R-COO-R); acid anhydrides (R-CO-O-CO-R); and amides (R-C(O)-NR 2 ). There are many important organic solvents that contain oxygen including: acetone, methanol, ethanol, isopropanol, furan, THF, diethyl ether, dioxane, ethyl acetate, DMF, DMSO, acetic acid, and formic acid. Acetone ((CH 3) 2CO) and phenol (C 6H 5OH) are used as raw materials in the synthesis of many different substances. Other important oxygen-containing organic compounds are: glycerin, formaldehyde, glutaraldehyde, citric acid, acetic anhydride and acetamide. Epoxies are ethers where the oxygen atom is part of a three-atom ring. Oxygen spontaneously reacts with many organic compounds at or below room temperature in a process termed autoxidation.[74] Most oxygenated organic compounds are not obtained by direct exposure to O 2 . Important industrial and commercial organic compounds obtained by direct oxidation of a precursor are ethylene oxide and peracetic acid.[71] ]

Acetone is an important ingredient in the chemical industry. OxygenCarbonHydrogen|alt=A spherical structure of a molecule. Its backbone is a zigzag chain of three carbon atoms connected to an oxygen atom in the middle and 6 hydrogen atoms at the end.

Oxygen makes up more than 40% of the molecular mass of the ATP molecule.

The element is found in almost all biomolecules essential to (or produced by) life. Only a few common complex biomolecules such as squalene and carotenes do not contain oxygen. Of the biologically relevant organic compounds, carbohydrates contain the highest mass fraction of oxygen. All fats, fatty acids, amino acids and proteins contain oxygen (due to the presence of carbonyl groups in these acids and their ester residues). Oxygen is also found in the phosphate groups (PO3-4) in the biologically important energy carrier molecules ATP and ADP, in the skeleton and in purines (except adenine) and pyrimidines of RNA and DNA, and in bone as calcium phosphate and hydroxyapatite.

oxygen

319

Safety and Precautions NFPA 704 standard classifies compressed oxygen gas as non-hazardous, non-flammable, and non-reactive but oxidizing. Refrigerated liquid oxygen (LOX) receives a health hazard rating of 3 (for increased risk of hyperoxia from condensed vapors and for hazards common to cryogenic liquids such as freezing), and all other ratings are the same as compressed gas form.

toxicity

[75]

Main symptoms of oxygen poisoning

Gaseous oxygen (O2) can be toxic at high partial pressures, leading to seizures and other health problems.[][76][77] Oxygen toxicity usually begins at partial pressures greater than 50 kilopascals (kPa), composition 50% oxygen equals standard pressure or 2.5 times the normal partial pressure of O 2 at sea level of about 21 kPa. This is not a problem, except in the case of mechanically ventilated patients, since the gas supplied through oxygen masks in medical applications usually contains only 30 to 50% by volume of O 2 (approx. 30 kPa at normal pressure).[18] (However, this value is also subject to strong fluctuations depending on the mask type). In the past, premature babies were placed in incubators with oxygen-rich air, but this practice was discontinued after some babies went blind because the oxygen levels were too high.[18]

Breathing pure O 2 in space applications such as some modern space suits or early spacecraft such as Apollo is not hazardous due to the low total pressures used. [][78] For space suits partial O 2 The pressure in the inhaled gas is usually about 30 kPa (1.4 times normal). Oxygen toxicity occurs when oxygen is absorbed by the lungs and the resulting O 2 is greater than the normal O 2 partial pressure at the astronaut's partial arterial pressure 2 , which can occur during deep dives. the blood is only slightly higher than the normal O 2 partial pressure at sea level (see Space suit and arterial blood gases for more on this). Oxygen toxicity to the lungs and central nervous system can also occur during deep dives and in water with a supply.[18][] Prolonged inhalation of a mixture of air and O

oxygen

320

partial pressures greater than 60 kPa can eventually lead to permanent pulmonary fibrosis.[] Exposure to O 2 partial pressures greater than 160 kPa (about 1.6 atm) can cause seizures (often fatal to divers). Acute oxygen toxicity (which causes seizures, the effect most feared by divers) can occur when a 21% O 2 -air mixture is breathed at 66 m (200 ft) or more; The same thing can happen if you inhale 100% O[][][][] 2 in just 20 feet. two

Combustion and Other Hazards Highly concentrated sources of oxygen promote rapid combustion. There is a risk of fire and explosion when encountering concentrated oxidizers and combustibles; however, an ignition event such as heat or a spark is required to initiate combustion. [ ] Oxygen itself is not the fuel, but the oxidizing agent. Combustion hazards also apply to oxygen compounds with high oxidizing potential such as peroxides, chlorates, nitrates, perchlorates and dichromates as they can add oxygen to the fire. The interior of the Apollo 1 command module.

Concentrate O Pure O [] 2 enables rapid and powerful combustion. Steel 2 with above-average pressure and a spark caused a fire and the loss of the crew of Apollo 1. Pipes and storage tanks used to store and transfer gaseous and liquid oxygen serve as fuel; Therefore, the design and manufacture of O[] 2 systems require special training to ensure ignition sources are minimized. The fire that killed the Apollo 1 crew in a launch pad test spread so quickly because the capsule was pressurized with pure O 1 2 , but at a pressure slightly above atmospheric pressure, rather than normal Pressure ⁄ that would be used on a mission 3 . [ 79][] Spilled liquid oxygen, when penetrating organic materials such as wood, petrochemicals and asphalt, can cause these materials to explode unpredictably upon subsequent mechanical impact. [] As with other cryogenic liquids when in contact with it. The human body can cause skin and eye burns.

Notes [2] Emsley 2001, p.297 [4] Cook & Lauer 1968, p.500 [5] Distribution of elements in the human body (by weight) (http://www.daviddarling.info/encyclopedia/E/elbio .html) Retrieved 2012-07-09 [8] An orbital is a quantum mechanical concept that models an electron as a wave-like particle that has a spatial distribution around an atom or molecule. [9] Emsley 2001, p. 303 [11] Oxygen paramagnetism can be used analytically in paramagnetic oxygen gas analyzers that determine the purity of oxygen gas. ("Oxygen Analyzer Company (Triplet) Literature" (http://www.servomex.com/oxigen_gas_analyser.html). Servomex. Retrieved 15 December 2007.) [18] Emsley 2001, p. 299 [24] Emsley 2001 , p.298 [25] The values given refer to values above the surface [26] From The Chemistry and Fertility of Sea Waters by H.W. Harvey, 1955, citing C.J.J. Fox, "On the absorption coefficients of atmospheric gases in sea water", Publ. Circle Disadvantages Explore Mer, no. 41, 1907. However, Harvey points out that later articles in Nature found the values to be 3% too high. [27] Emsley 2001, p.301 [31] Thylakoid membranes are part of chloroplasts in algae and plants, while in cyanobacteria they are just one of many membrane structures. In fact, chloroplasts are thought to have evolved from cyanobacteria that were once symbiotic partners with plant progenerators

oxygen algae. [32] Raven 2005, 115–27 [33] The oxidation of water is catalyzed by a manganese-containing enzyme complex known as the oxygen-evolving complex (OEC) or water-splitting complex associated with the luminal side of thylakoid membranes. Manganese is an important cofactor, and calcium and chloride are also needed for the reaction to take place. (Raven 2005) [34] "For humans, the normal volume is 6 to 8 liters per minute." (http://www.patentstorm.us/patents/6224560-description.html) [35] (1.8 grams /min/person) × (60 min/h) × (24 h/day) × (365 days) / year )×(6.6 billion people)/1 000 000 g/t=6.24 billion tons [36 ] Derived from mmHg values using 0.133322 kPa/mmHg [37] Normal Reference Range Table (http://pathcuric1.swmed.edu/PathDemo/nrrt.htm) from the University of Texas Southwestern Medical Center at Dallas. Used in an interactive case study add-on for the pathological basis of the disease. [38] The Medical Education Division of the Brookside Associates--> ABG (Arterial Blood Gas) (http://www.brooksidepress.org/Products/OperationalMedicine/DATA/operatingmed/Lab/ABG_ArterialBloodGas.htm) Accessed 6 December 2009 [ 42] Cook & Lauer 1968, p.499. [43] Emsley 2001, p. 300 [47] However, these results were largely ignored until the 1860s. Part of this rejection was based on the assumption that atoms of one element would have no chemical affinity for atoms of the same element, and in part it was due to obvious exceptions to Avogadro's law, which were only later explained in relation to the dissociation of molecules. [48]Poland – culture, science and media. Condensation of oxygen and nitrogen (http://www.poland.gov.pl/Karol,Olszewski,and,Zygmunt,Wroblewski:,condensation,of,oxygen,and,nitrogen,1987.html). Accessed on 04/10/2008. [52] Cook & Lauer 1968, p. 510 [59] The reason for this is that increasing the fraction of oxygen in the low-pressure breathing gas causes the inspired partial pressure to increase closer to that found at sea level. [62] Cook & Lauer 1968, p.508 [63] Emsley 2001, p.304 [66], p. 28 [69] Since oxygen also has a higher electronegativity than hydrogen, the charge difference makes it a polar molecule. The interactions between the different dipoles of each molecule cause a net attractive force. [71] Cook & Lauer 1968, p. 507 [73] Cook & Lauer 1968, p. 505 [74] Cook & Lauer 1968, p. 506 [76] Since the partial pressure is the fraction times the total pressure, elevated partial pressures can result from a high fraction in the breathing gas or a high pressure of the breathing gas or a combination of both. [77] Cook & Lauer 1968, p.511 [79] No ignition source for the fire has been positively identified, although some evidence suggests an arc from an electrical spark.

(Apollo Review Board Report 204 NASA Historical References Collection, NASA History Office, NASA Headquarters, Washington, DC)

Quotations References • Cook, Gerhard A.; Lauer, Carol M. (1968). "Oxygen". In Clifford A. Hampel. The Encyclopedia of the Chemical Elements. New York: Reinhold Book Corporation. pp. 499-512. LCCN 68-29938 (http://lccn.loc.gov/68-29938). • Emsley, John (2001). "Oxygen". The Building Blocks of Nature: An A to Z Guide to the Elements. Oxford, England, UK: Oxford University Press. pp. 297-304. ISBN0-19-850340-7. • Rabe, Peter H.; Ray F Evert, Susan E Eichhorn (2005). Plant Biology, 7th Edition. New York: WH Freeman and Company Publishers. pp. 115-27. ISBN0-7167-1007-2.

321

oxygen

Further Reading • Walker, J. (1980). "The Oxygen Cycle". In Hutzinger O. Handbook of Environmental Chemistry. Volume 1. Part A: The natural environment and biogeochemical cycles. Silk; Heidelberg; New York: Springer Verlag. p.258. ISBN0-387-09688-4.

External links • Oxygen (http://www.periodicvideos.com/videos/008.htm) at The Periodic Table of Videos (University of Nottingham) • Oxidants > Oxygen (http://www.organic-chemistry.org/chemist /oxidations/oxygen.shtm) • Properties, uses and applications of oxygen (O2) (http://www.uigi.com/oxygen.html) • Article by Roald Hoffmann on “The History of O” (http:// www.americanscientist.org/template/AssetDetail/assetid/29647/page/1) • WebElements.com - Oxygen (http://www.webelements.com/webelements/elements/text/O/index.html) • Chemistry in his Elements podcast (http://www.rsc.org/chemistryworld/podcast/element.asp) (MP3) from Chemistry World: Oxygen by the Royal Society of Chemistry (http://www.rsc.org/images/ CIIE_oxygen_48k_tcm18 - 117681).mp3) • Oxygen (http://www.bbc.co.uk/programmes/b0088nql) via In Our Time on the BBC. (Listen now (http://www.bbc.co.uk/iplayer/console/b0088nql/In_Our_Time_Oxygen)) • Scripps Institute: Atmospheric oxygen has been declining for 20 years (http://scrippso2.ucsd.edu/)

322

Sopormetall

323

Sopormetal Sopormetal – Sociedade Portuguesa de Metais, Lda.

He writes

welding

Founded

February 2, 1985

Headquarters Portugal products

Soldering, soldering, joining metals, soft soldering, silver hard solders, phosphorus-copper alloys, solders, fluxes

Website-Web

www.sopormetal.com

[1]

Sopormetal Internacional Group was founded on February 2, 1985. It was born in the Portuguese market with the aim of manufacturing and supplying solutions for soldering materials, silver and copper solders. During its long journey, this company has defined several stages that have contributed to a sustainable and continuous development, including consolidating its position in the Portuguese market and achieving the status of leader. Also, the Nobel Prize in Portugal for “SME Leader”[1] by IAPMEI was attributed to companies that achieve high financial and quality performance. With a production unit headquartered in Albergaria-a-Velha that manufactures soldering consumables (with different compositions and preforms) for various industries – automotive, aeronautics and marine, gas and electronics, etc. – this company could not sustain its strategy solely on the Portuguese to be active in the market and thus to have developed an international expansion strategy.

Production SOPORMETAL produces hard solders such as silver, copper-phosphorus solders, soft solders and flux. Cadmium-free silver solder, special alloys and trimetallic alloys for all industries, as well as various special alloys in the form of rods, strips, rings and various semi-finished products. Silver-coated solders with different proportions, taking into account the soldering technology used and the technical melting parameters. Phosphorus-copper alloys with and without silver for all industries, as well as with different types of profiles such as rods, plates, strips, wires. Powder, gel and liquid soldering fluxes for any type of alloy or soldering technology.[2]

Internationalization Sopormetal's globalization strategy starts with the acquisition of a Spanish company, which leads to the installation in Madrid of Sopormetal Spain, today considered a major “player” in the industrial sector in the Spanish market, covering it completely and including large companies such as Airbus, Vasca Mondragón Corporation and Siemens. In this context, the company begins its expansion, which currently supplies almost the entire European continent and the Maghreb, with the establishment of a “commercial office” in Dubai to serve the Middle East market and

Sopormetall

324

also entering the North American market with the aim of consolidating a strategic position worldwide. This internationalization strategy resulted in the project for a new production unit - Sopormetal Brasil - which is to be put into operation shortly. This investment is an important step towards consolidation in the South American market and a commitment to the supply of raw materials that is vital for the entire group.[3] The company also exhibited continuously at trade fairs such as Chillventa,[4] BiemH,[5] BIG5,[6] Schweissen & Schneiden[7].

Renewal The investment policy of this company would not be sufficient if the Sopormetal Internacional Group did not invest in its current capacities and in the creation of a new production unit in Portugal, a priority in its expansion plan. This new production unit, already operational, will be equipped with the latest technology in accordance with current international standards and will have a much higher production capacity than the current one and is expected to be operational within three months.

references

List of brazing alloys composition in % by weight

family

solid-liquid

Poisonous

Remarks

copper

Zink

Agriculture

point it out

Von

Mes

Minnesota

trust

company

nice

Alabama

Ponto (°C) Al94,75Si5,25

Alabama

Al92.5Si7.5

Alabama

Al90Si10

Alabama

Al88Si12

Alabama

[]

–

BAlSi-1, AL 101

94,75

5.25

[]

–

AL102cu

92,5

7.5

[]

–

BAlSi-5, AL 103

[] [1]

–

BAlSi-4, AL 104, AL 718,

575/630

575/615

575/590

575/585

L-ALSi12, BrazeTec

577/582

L88/12. Most aluminum solders are pourable. General purpose filler metal, can be used with weldable aluminum in all types of brazing. For joining aluminum and its alloys. Can be used to join aluminum and titanium to dissimilar metals; then the risk of galvanic corrosion must be considered. Excellent corrosion resistance when joining aluminum metals. Off-white color. It can be used for both flame brazing and furnace brazing.

PAG

From others

List of hard solders

Al86Si10Cu4

Alabama

325 []

–

4. BAlSi-3, AL 201, AL 716

88,75

9,75

Mg1.5

88,65

9,75

Mg1,5Bi0,1

520/585

General purpose filler metal, can be used with weldable aluminum in all types of brazing. For joining aluminum and its alloys. Good corrosion resistance. Can be used to join aluminum and titanium to dissimilar metals; then the risk of galvanic corrosion must be considered. Tends to liquify, must be heated quickly to melting point. Off-white color. Al88.75Si9.75Mg1.5

Alabama

[]

–

AL 301. Suitable for

555/590

Vakuumlöten. Al88.65Si9.75Mg1.5Bi0.1

Alabama

[]

–

AL 302. Suitable for

555/590

Vakuumlöten. Al76Cu4Zn10Si10

Alabama

[2]

–

AL 719. Join

516/560

Aluminum and its alloys. It can be used to weld aluminum that cannot be welded in any other way, e.g. Casting Used with flux. Not suitable for vacuum brazing due to the high zinc content. Worse corrosion resistance due to higher alloy. Tends to liquify, must be heated quickly to melting point. Off-white color.

[3]

Zn98Al2

–

AL 802. Allzweck

382/392

Filler metal for welding/brazing aluminium. Off-white color. Al73Cu20Si5Ni2Bi0.01Be0.01Sr0.01

Al-Cu-Si

[]

–

For soldering aluminium.

Bi, Ser, Sr

1.2

61.3

4.5

Bi–Be–Sr

515/535

Traces of bismuth and beryllium decompose the surface of alumina. Strontium refines the granular structure of the brazing alloy and improves ductility and toughness. Al61.3Cu22.5Zn9.5Si4.5Ni1.2Bi0.01Be0.01Sr0.01 Al–Cu–Si

[]

–

For soldering aluminium.

495/505

Traces of bismuth and beryllium decompose the surface of alumina. Strontium refines the granular structure of the brazing alloy and improves ductility and toughness.

22,5

9.5

List of hard solders

Al71Cu20Si7Sn2

Al-Cu-Si

Al70Cu20Si7Sn2Mg1

Al-Cu-Si

326 []

–

For soldering aluminium.

[]

–

For soldering aluminium.

[4]

–

AL 815. Allzweck

505/525

mg1

501/522

Zn85Al15

fifteen

381/452

Filler metal for welding/brazing aluminium. Off-white color.

[5]

Zn78Al22

–

AL 822. High durability,

426/482

low temperature. For aluminum with aluminum and aluminum with copper. Cu80Ag15P5

Cu-Ag-P

[] [] 645/700 []

–

BCup-5, CP 102, CP1,

643/802

Sil-Fos, Silvaloy 15, Matti-phos 15. Duktil,

645/800

Slow flow Void filling. It withstands torsional loads, shock loads and bending. For copper, copper alloys, brass, bronze. Mainly for copper to copper. It can also be used on silver, tungsten and molybdenum. Low resistance to vibration. Light copper color. It is used in sanitary engineering. It is commonly used for resistance soldering. It is used where ductility is important and tight tolerances cannot be achieved. Ductile copper-copper connections. It is used in electrical assemblies, e.g. motors or contacts. Used in refrigeration and air conditioning systems and in the assembly of brass and copper pipes. More liquid than BCuP-3 due to higher phosphorus content. Mutually soluble with copper and copper alloys. Strong tendency to liquefaction. Also available in tape and sheet form. Clearance 0.051-0.127mm (0.05-0.2mm). Pour point 705°C. Maximum use temperature 149°C (flashing 204°C).

fifteen

List of hard solders

Cu75,75Ag18P6,25

327 [6]

Cu-Ag-P

–

Silvaloy 18M. above

75,75

6.25

45,75 36

75,9

17.6

6.5

643/668

eutectic, narrow melting range, suitable for low heating rates, e.g. in a soldering oven. Very liquid, for firm joints. For copper, copper alloys, brass, bronze. It can also be used on silver, tungsten and molybdenum. Due to the low melting point, it is suitable for joining copper to brass, since the loss of zinc from brass is less pronounced. Light copper color. Maximum use temperature 204°C (flashing 260°C). Cu45.75Ag18Zn36Si0.25

[7]

Ag-Cu-Zn

–

Mattisil 18Yes. more economical

0,25

784/816

Alternative to high silver content alloys. Suitable for the automotive industry for brazing steel components where high temperature bronze alloys cannot be used. Gap 0.075-0.2mm. Cu75.9Ag17.6P6.5

[8]

Cu-Ag-P

–

Sil-Fos 18. Eutectic. For

643

Copper, brass and bronze alloys. copper self-fluxing. Extremely liquid. A good fit is required. Clearance 0.025-0.075mm. Grey colour. Cu89Ag5P6

Cu-Ag-P

[] [] 645/825 []

–

BCuP-3, CP104, CP4,

643/813

Sil-Fos 5, Silvaloy 5, Matti-phos 5.

645/815

Slow flow, very fluid. Cheaper than BCup-5. It can fill holes and form fillets. Strong tendency to liquefaction. For soldering copper pipes used in plumbing. It is used for fluxless brazing in refrigeration, air conditioning, medical gas lines and heat exchangers. Gap 0.051-0.127mm. Pour point 720 °C. Light copper color. Maximum use temperature 149°C (flashing 204°C).

List of hard solders

Cu88Ag6P6

Cu-Ag-P

328 [9]

–

Silvaloy 6. Fließpunkt 720 88

86,75

7.25

90,5

643/807

ºC For copper, copper alloys, brass, bronze. Mainly for copper to copper. It can also be used on silver, tungsten and molybdenum. Low resistance to vibration. Light copper color. Maximum use temperature 149°C (flashing 204°C). Cu86.75Ag6P7.25

Cu-Ag-P

[] [10] 645/750 [11]

–

BCuP-4, Sil-Fos 6,

645/720

Matti-phos 6. Very fluid, fast flow, for tight areas

641/718

Seals Low melting range. Pour point 690 °C. The lowest melting point of low silver content alloys. Inexpensive. It is used for fluxless brazing in refrigeration, air conditioning, medical gas lines and heat exchangers. It tends to liquefy. Extremely fluid above pour point, easily penetrates tight spaces. Clearance 0.025-0.076mm (0.05-0.2mm). Less ductile than BCuP-1 or BCuP-5. Cu90.5Ag2P7

Cu-Ag-P

[]

–

PC202, PC3. Fill gaps.

705/800

It is used in sanitary engineering. Cu91Ag2P7

Cu-Ag-P

[] [][12] 645/875 [13] 643/788 [14]

–

BCuP-6, CP 105, Sil-Fos

643/802

2, Silvaloy 2, Matti-phos 2. Middle Current. Pour point 704-720°C. a lot of

641/780

Liquid, can enter confined spaces. Clearance 0.025 to 0.127mm (0.05 to 0.2mm). Comparable to Fos-Flo 7. For copper, copper alloys, brass, bronze. Mainly for copper to copper. It can also be used on silver, tungsten and molybdenum. Low resistance to vibration. It tends to liquefy. Light copper color. Maximum use temperature 149°C (flashing 204°C).

List of hard solders

Cu91.5Ag2P6.5

Cu-Ag-P

329 [15]

–

Silvaloy 2M. Average

91,5

6.5

1,5

6.8

643/796

Flow. Pour point 718°C. Very fluid, can penetrate tight spaces. For copper, copper alloys, brass, bronze. Mainly for copper to copper. It can also be used on silver, tungsten and molybdenum. Low resistance to vibration. Light copper color. Maximum use temperature 149°C (flashing 204°C). Cu91.7Ag1.5P6.8

Cu-Ag-P

[sixteen]

–

silvalite. For copper, brass 91.7

643/799

and bronze. copper self-fluxing. It can also be used on silver, tungsten and molybdenum. Mainly for copper to copper connections. Low resistance to vibration. Good for narrow copper tubes and pipes. Extremely fluid, penetrates even the thinnest joints. Light copper color. Maximum use temperature 149°C (flashing 204°C). Pour point 732°C. Ideal soldering temperature just above the flow point. Slow at low temperature, suitable for plugging holes. Very fluid at high temperatures, suitable for deep penetration into very narrow joints. Cu92.85Ag1P6Sn0.15

Cu-Ag-P

[17]

–

Silvabraze 33830. Para

92,85

0,15

643/821

copper, brass and bronze. copper self-fluxing. It can also be used on silver, tungsten and molybdenum. Mainly for copper to copper connections. Low resistance to vibration. Good for narrow copper tubes and pipes. Extremely fluid, penetrates even the thinnest joints. Light copper color. Maximum use temperature 149°C (flashing 204°C). Cu93.5P6.5

Taxes

[]

–

PC105, PC2. Fill gaps.

645/740

It is used in sanitary engineering.

93,5

6.5

List of hard solders

Cu92.8P7.2

Taxes

330 [][18] []

–

BCup-2, Fos-Flo 7,

92,8

7.2

93,85

6.15

710/793

Silvaloy 0, Copper-flo.

710/795

Fast flow, very fluid. It can withstand moderate vibration and is not very ductile. For copper, brass and bronze. Mainly for copper to copper. It can also be used on silver, tungsten and molybdenum. For connecting tight fittings and pipes, it penetrates into narrow spaces. Not suitable for larger spaces, should only be used where a good fit can be guaranteed. For heat exchanger return bends, hot water tanks, cooling tubes. Pour point 730 °C. Spacing 0.051-0.127mm (0.075-0.2mm, 0.025-0.076). It tends to liquefy. Maximum operating temperature 149 °C, short term 204 °C. Steel gray color. Cu93.85P6.15

Taxes

[]

–

Fos-Flo 6. Ductile,

710/854

moderate flow. Economically. Wide melting range. Used where joint tolerances are greatest and ductility is important. Pour point 746°C. Gap 0.076-0.127mm. Cu97Ni3B0.02-0.05

[]

copper

–

CU 105. Liquid. capable of 97

0,05

1085/1100

Fill gaps larger than pure copper (up to 0.7 mm in extreme cases). Cu99Ag1

[]

copper

–

CU 106. Slightly lower

1070/1080

Melting point than pure copper. More expensive due to silver content. Rarely used now. Can be used according to CU 105 for step soldering. Cu95Sn4.7P0.3

[]

Com-Sn

–

CDA 510. Bronze. For

4.7

0,3

93,5

6.3

0,2

953/1048

Steels that require a lower temperature than pure copper. Cu93.5Sn6.3P0.2

[]

Com-Sn

–

CU 201. Bronze. require

910/1040

Fast heating to avoid problems with a large melting range.

List of hard solders

Cu92Sn7.7P0.3

331 []

Com-Sn

–

CDA 521. Bronze. For

7.7

0,3

87,8

0,2

86,5

6.5

86,8

6.2

881/1026

Steels that require a lower temperature than pure copper. Cu87.8Sn12P0.2

Com-Sn

[]

–

GE 202. Bronze. requires

825/990

Fast heating to avoid problems with a large melting range. Cu86.5Sn7P6.5

Com-Sn

[19]

–

Silvacap 35490. Bronze.

649/700

copper self-fluxing. Generally offers stronger bonds than base metals. It is used to join tight tolerance copper assemblies. Maximum operating temperature 204°C, short term 316°C. Cu86.8Sn7P6.2

Com-Sn

[20]

–

Fos-Flo 670. Scattered.

657/688

Useful for joining copper to copper or copper alloys where strong shock and vibration are not encountered. Requires good assembly. copper self-fluxing. Cashless Extremely fluid above the pour point, for tight connections. Clearance 0.025-0.075mm. light brown. Cu85.3Sn7P6.2Ni1.5

Com-Sn

[21]

–

Fos-Flo 671. Low cost.

85,3

1,5

612/682

Cu-Zn

[][]

–

CU 301. Brass. cans

58,5

41.3

CU 302. Latin. For carbon 58.5

41.1

0,2

875/895

They are often used on mild steel sets. For use on brass, bronze and low carbon steel. It is used in sanitary engineering. Cu58.5Zn41.1Sn0.2Si0.2

Cu-Zn

[][]

–

0,2

875/895

steel and galvanized steel. It is used in sanitary engineering. Cu60Zn39.55Si0.3Mn0.15

Cu-Zn

[]

870/900

–

CU 303. Messing.

39,55

0,15

0,3

List of hard solders

Cu60Zn39.8Ni10Si0.2

Cu-Zn

332 [22]

–

BrazeTec 60/40. steam

39,8

0,2

875/890

Brazing of galvanized pipes. Similar to CU 303. Cu60Zn29.35Sn0.35Si0.3

Cu-Zn

Cu60Zn40

Cu-Zn

[]

–

CU 304. Messing.

29.35

[]

–

RBCuZn-C, CDA 681.

45.4

41,8

38,25

0,35

0,3

0,5

0,1

870/900

865/887

Brass. Fluid. For iron, copper and nickel alloys. Cu46Zn45.4Sn0.5Si0.1Ni8

Cu-Zn

[][]

–

CU 305. Brass. to use in it

890/920

Carbon and galvanized steel, tensile strength slightly higher than CU 302. Used in plumbing. Cu48Zn41.8Ni10Si0.2

Cu-Zn

[22]

–

BrazeTec 48/10. steam

0,2

890/920

Tubular steel frame for brazing. Cu56Zn38.25Sn1.5Si0.5Mn0.2Ni0.2

Cu-Zn

[][]

–

CU 306. Brass. to use in it

0,2

9.5

23,5

1,5

0,5

870/890

Cast iron and malleable iron. It is used in sanitary engineering. Cu54.85Zn25Mn12Ni8Si0.15

Cu-Zn

[]

–

high temperature 080

54,85 25

855/915

Economically. High resistance. For joining hard metals with steel alloys. Light yellow joint. Cu52.5Mn38Ni9.5

Cu–Mn

[] [23]

–

AMS 4764, high temperature 095, 52.5

855/915

Nicoman 38.

879/927

High resistance. For hard metals, steels, stainless steels, cast iron and high-melting nickel alloys. Ideal for combined brazing/heat treating. Good for materials where soldering copper would require too high a temperature or where boron alloys would be detrimental. Relatively free flow; the melting point can be raised as more nickel is leached from the base metal. Fluxless soldering requires a vacuum, argon, or dry hydrogen atmosphere. Red gray color. Cu67.5Mn23.5Ni9

Cu–Mn

925/955

–

Nicoman 23.

67,5

0,15

List of hard solders

Cu55Zn35Ni6Mn4

Cu-Zn

333 [] [24]

–

High Temp 548, Silvaloy

880/920

X55. changed

866/885

nickel silver. Moderate resistance, hardy. Excellent plasticity in the molten state. Fill gaps. Excellent strength and ductility on cooling, which is an advantage over silver filler metals when joining materials with different thermal expansions. For hard metals, stainless steels, tool steels and nickel alloys. Used to connect carbide tool tips to steel holders. Pale yellow color. May contain 0.2% silicone for better flow. For induction, torch and furnace soldering. Cu87Mn10Co2

[]

Cu–Mn

–

High temperature 870.

960/1030

High temperature resistance. It flows freely. For hard metals, stainless steels, tool steels and nickel alloys. Excellent wetting of hard metals, stainless steel and copper. Good void filling at low soldering temperatures. Flux-free soldering is possible in a vacuum or in a suitable atmosphere. Brazing is usually done in conjunction with a heat treatment. Cu87.75Ge12Ni0.25

copper

[]

880/975

–

Gemco. Used for special purposes, e.g. Brazing of CFC (carbon fiber composite materials), pure copper, copper and zirconium alloys

[25]

and molybdenum.

Since brazing contains no active elements, carbon-based material may need to be surface treated to sufficiently wet it, e.g. by a solid state reaction with

[26]

Chrom.

87,5

0,25

Ge12

List of hard solders

Ag38Cu32Zn28Sn2

Ag-Cu-Zn

334 [] [] 650/720 [27]

–

BAg-34, AMS 4761,

649/721

Braze 380, Silvaloy A38T. free flow to

660/720

Iron alloys, nickel, copper and their alloys and combinations. The tin content improves the wetting of cemented carbide, stainless steel and other difficult metals. The absence of lead and cadmium allows the use of long heating cycles. Cheaper BAg-28 alternative with similar characteristics. Suitable for controlled atmosphere brazing without flux. It is mainly used in furnace brazing. Best for tight spaces. General purpose air conditioning alloy for bonding steels, copper and copper-nickel alloys. Gap 0.075-0.2mm. Pale yellow color. Maximum operating temperature 204°C (flashing 316°C). Ag40Cu30Zn30

Ag-Cu-Zn

[] []

–

Brasagem 401, AMS 4762.

674/727

low temperature, enough

675/725

it flows freely. Narrow melting range. For ferrous and non-ferrous metals. For copper, brass, nickel silver, bronze, mild steel, stainless steel, nickel and monel alloys. Cadmium-free replacement for BAg-2a. Moderate liquefaction, but can be used to fill larger gaps. Pale yellow color.

List of hard solders

Ag45Cu30Zn25

Ag-Cu-Zn

335 [][28] [] 665/745 [29]

–

BAG-5, Messing 450,

18.3

25,62 45,75

1,93

663/743

Silvaloy A45, Matti-sil 45. Low temperature. front

675/735

Ferrous, non-ferrous and dissimilar metals. For band instruments, brass lamps, ship tubes, oil coolers for aircraft engines. It can be used in the food industry. Allows for larger joint spacing. Sufficient melting range for welding spaced joints commonly found in commercial pipe and fittings. Yellow-white color. Maximum operating temperature 204°C (flashing 316°C). Gap 0.075-0.2mm. Ag45.75Cu18.3Zn25.62Ni1.93

Ag-Cu-Zn

Ag50Cu20Zn28Ni2

Ag-Cu-Zn

–

[] []

–

BAG-24, AMS 4788,

660/707

Solder 505, Silvaloy

660/705

A50N, Argo Hard Solder 502. For most metals including stainless steel and carbides. Highly recommended. Recommended for 300 series stainless steel. Well suited for food processing applications with tight joint tolerances. Clearance from 0.1 to 0.25mm. Alloy specially formulated for welding carbide tips to steel tools and wear parts. Easily wets nickel and iron alloys. Nickel compensates for the diffusion embrittlement of aluminum when soldering aluminum bronzes. Delays interfacial corrosion where base metals can resist. Zinc-free alloys are recommended where there is a risk of zinc loss, e.g. Contact with high temperature salt water. Very fluid, quickly fills long and narrow joints. It tends to liquefy. White-yellow color. Cadmium-free replacement for BAg-3.

List of hard solders

Ag54Cu40Zn5Ni1

Ag-Cu-Zn

336 [] [30]

–

BAG-13, AMS 4772,

725/855

Solder 541, Silvaloy

718/857

A54N. Brazing in an atmospheric furnace. Melts pasty, tends to liquefy. Wider melting range, suitable for uneven gaps. Suitable for hand feeding joints with large gaps as soft alloy can be formed. For joining ferrous, non-ferrous and mixed metals. Due to its low zinc content, it is used in furnace brazing. For high temperature applications, e.g. in jet engines, especially in stainless steel; maximum service temperature 371 °C. Used in many jet engine subassemblies for the US Air Force. Color is white. Ag56Cu42Ni2

Ag-Cu

[] [31]

–

Bolsa-13a, AMS 4765,

770/895

Brasagem 559. Atmosfera

771/893

furnace brazing. For high-temperature applications (up to 370 °C), e.g. in jet engines. zinc free; Used in place of BAg-13 when zinc fumes are not allowed in the furnace. Similar to BAg-13. It tends to liquefy. Can be used for wide joints. Can be used with flux but is primarily used for fluxless furnace brazing of stainless steel in dry hydrogen. The white color. Ag49Cu16Zn23Mn7.5Ni4.5

Ag-Cu-Zn

[] [32]

–

BAg-22, AG 502, brasagem

680/700

495, Silvaloy A49NM,

682/699

Argo welding 49H. Low temperature. For carbide and all types of carbon steel and stainless steel. For bonding carbide tips to steel beams. Excellent wetting properties, widely used for securing tungsten carbide bits to cutting tools and drills. It tends to liquefy.

sixteen

7.5

4.5

List of hard solders

Ag49Cu27,5Zn20,5Mn2,5Ni0,5

Ag-Cu-Zn

337 [33]

–

Argo 49LM welding. For

27,5

20,5

fifteen

Sixty-five

2.5

0,5

670/710

Fixation of carbide tips on steel beams. Supplied as a trifoil: copper foil sandwiched between sheets of solder alloy. The copper layer helps absorb stress caused by differential heating. Ag65Cu20Zn15

Ag-Cu-Zn

[]

–

BAg-9, soldering 650th paragraph

670/720

Iron, silver and nickel alloys. Slight tendency to liquefy. silvery white; used in jewelry because of the color combination. Corrosion resistant. Changed remelting temperature when dissolving the base metal; increased by silver, decreased by copper. Often used for step soldering. Ag65Cu28Mn5Ni2

Ag-Cu

[]

–

Braze 655. For leagues like

Sixty-five

750/850

Kovar and Invar for copper, for vacuum tubes. Like friction seals in jet engines. Ag70Cu20Zn10

Ag-Cu-Zn

[]

–

BAg-10, Braze 700. Single paragraph

690/740

Cutlery. Wet iron and nickel alloys. For step soldering with BAg-9 as the next step. Slight tendency to liquefy. silvery white; used in jewelry because of the color combination. Corrosion resistant. Changed remelting temperature when dissolving the base metal; increased by silver, decreased by copper. Often used for step soldering.

List of hard solders

Ag56Cu22Zn17Sn5

Ag-Cu-Zn

338 [] [][][34] 618/652 []

–

620/655

BAg-7, AG 102,

L-Ag55Sn, Ag 1, AMS 4763, Lot 560, Silvaloy

620/650

A56T, Matti-sil 56Sn, BrazeTec 5600. Low melting point. Excellent for general soldering of tight tolerance joints. Cadmium-free silver alloy with the lowest melting point. Low zinc content minimizes problems with prolonged or repeated heating. Slight tendency to liquefy. It is used in sanitary engineering. Used in food equipment. Clearance 0.05-0.15mm. The white color; Due to the excellent color match, it is often chosen for silver or stainless steel. Maximum operating temperature 204°C (flashing 316°C). For soldering steel, copper and its alloys, nickel and its alloys. Good alternative to solder containing cadmium. Good absorption. It can be used for induction brazing and flame brazing. Used in electrical engineering, automotive industry and

[35]

tool manufacture.

For

For higher corrosion resistance on stainless steel, use a nickel-containing alloy, e.g. BAg-24 or BAg-21. Ag57.5Cu32.5Sn7Mn3

Ag-Cu

[]

–

Braze 580. Free flow.

32,5

57,5

605/730

For brazing with carbide. Will wet some metals that are difficult to wet with standard alloys e.g. chromium and tungsten carbides. Despite the manganese content, it does not tend to become porous fillets. Excellent wetting of high manganese stainless steels in vacuum brazing. Gast not enough with the titanium nitride coating. Ag68Cu27Sn5

Ag-Cu

743/760

–

Cusiltin 5. Low vapor pressure. More powerful than BAg-8.

List of hard solders

Ag60Cu25Zn15

Ag-Cu-Zn

339 []

–

Solder 600. For nickel

fifteen

675/720

Alloys (e.g. Monel). For cutlery instead of BAg-9 if only one seal is required. Due to the dissolution of the base metal, the flowability decreased for copper and increased for silver. Easily wets nickel and iron alloys due to the zinc content. eutectic color white, slightly yellower than BAg-9. Ag71.5Cu28Ni0.5

Ag-Cu

[]

–

BAg-8b, BVAg-8b, AMS

780/795

4766, Braze 715, Braze 716 (VTG quality, for vacuum systems, with reduced volatile impurities) For ferrous and non-ferrous alloys. For atmospheric brazing of nickel and iron alloys. High electrical and thermal conductivity. Nickel modified silver-copper eutectic. The addition of nickel retards alloy formation but improves wetting of ferrous alloys. The dissolution of copper, silver or nickel from the base metal increases the remelting temperature. silver white.

71,5

0,5

List of hard solders

Ag72Cu28

340 [] [36]

Ag-Cu

–

BAg-8, BVAg-8, Silvaloy

71,7

780

B72, Messing 720, Messing

779,4

721 (VTG quality, for vacuum systems, with reduced volatile impurities). Eutectic For non-ferrous alloys. The remelting temperature is increased by dissolving copper or silver from base metals. High electrical and thermal conductivity. For flux-free soldering in a controlled atmosphere. Very liquid when melted. Limited wetting on nickel and ferrous metals, low wetting on carbon steel; in these cases the wetting is mediated by copper, since iron and nickel are not soluble in silver but are soluble in copper. Hydrogen wetting is superior to flux wetting. It is mainly used on copper and nickel alloys. Used with reducing, inert or vacuum atmospheres. Widely used for joining metallized ceramics to metals in vacuum. The white color. Maximum operating temperature 204°C (flashing 316°C). Ag71.7Cu28Li0.3

[]

Ag-Cu-Li 760

–

BAg-8a, Lithobraze 720, Lithobraze BT. high fluidity For ferrous and non-ferrous alloys. Particularly suitable for thin stainless steel. General purpose fluxless furnace brazing of stainless steels. Requires hydrogen or inert

[37]

The atmosphere.

Li0,3

List of hard solders

Ag92,5Cu7,3Li0,2

Ag-Cu-Li

341 []

–

760/890

BAg-19, Litobraze 925.

7.3

92,5

Li0,3

28,5

2.5

28.1

71,15

0,75

Good for precipitation hardened steel. It is commonly used to bond skins to honeycomb cores of precipitation hardened steel hull structures. General purpose fluxless furnace brazing of stainless steels. Not suitable for flame soldering. Requires hydrogen or an inert atmosphere, most often argon. White silver

[38]

Kor. Ag63Cu28,5Sn6Ni2,5

Ag-Cu

[] [39]

–

BAG-21, AMS 4774,

690/800

Hartlöten 630, Nicusilestanho 6.

691/802

For 400 series stainless steels. Resistant to chloride corrosion and dezincification; Resistant to chlorine solutions, salt spray, etc. Very slow, can save large spaces. It tends to liquefy. The combination brazing/heat treatment at over 925°C improves the fluidity of the alloy. Can be used in a protective atmosphere (e.g. hydrogen-nitrogen) or in a vacuum for flux-free soldering. It is used in food handling and in surgical equipment. It is used in connections that require higher corrosion resistance than alternative alloys offer. Used in vacuum applications. The white color. High strength, low vapor pressure. Ag71.15Cu28.1Ni0.75

Ag-Cu

780/795

–

Nicusil 3. Better durability and wetting than BAg-8.

List of hard solders

Ag75Cu22Zn3

Ag-Cu-Zn

342 []

–

Brazing 750. For cutlery. 22

sixteen

BAg-6b, BVAg-6b, Brasagem 17

740/790

For step soldering. Glaze; The low zinc content causes only a very small change in the enamel luster. Corrosion resistant. Changed remelting temperature when dissolving the base metal; increased by silver, decreased by copper. For iron or nickel alloys. silvery white; used in jewelry because of the color combination. The low zinc content minimizes zinc evaporation, especially in controlled atmospheres during fluxless soldering. Ag50Cu34Zn16

Ag-Cu-Zn

[] [40]

–

BAg-6, Messing 501, Messing

675/775

502, 503 Hartlöten, Silvaloy

677/774

A50. For steam turbine blades. For heavy duty galvanized steel, aluminum and brass tubing. Widely used in the electrical industry. Used in the dairy industry. Large melting range, can round and fill large gaps. Ag50Cu17Zn33

Ag-Cu-Zn

[]

–

780/870

502, Braze 503 (VTG quality for vacuum systems, with reduced volatile impurities). For non-ferrous alloys. High electrical and thermal conductivity. Greater gap-fill capability than the equivalent BAg-8. (DOUBT, see the other BAg-6b entry) Ag50Cu50

Ag-Cu

[]

–

BVAg-6b, Lotm 503.

779/870

degree of vacuum. For electronics where cadmium and zinc should be avoided.

List of hard solders

Ag61.5Cu24In14.5

Ag-Cu

343 []

–

BAG-29, BVAg-29,

61,5

a 14.5

she 10

625/705

Premabraze 616, Incusil 15. Vacuum quality. For ferrous and non-ferrous alloys in moderate temperature vacuum systems. a bit slow. It tends to liquefy. Can be used without flux in hydrogen, inert gas or vacuum. Indium improves the wettability of iron alloys. silver white. Lower melting point of ductile, low vapor pressure alloys. Ag63Cu27In10

Ag-Cu

[]

–

Premabraze 631, Incusil

685/730

10. Low vapor pressure. For ferrous and non-ferrous alloys. Ag65Cu20Zn15

Ag-Cu-Zn

Ag55Cu21Zn22Sn2

Ag-Cu-Zn

[]

–

[]

–

DP103.

fifteen

Sixty-five

27,75 25

2.25

850/900

630/660

AG 103, L-Ag55Sn, BrazeTec 5507. For brazing steel, copper and its alloys, nickel and its alloys. Good alternative to solder containing cadmium. Good absorption. It can be used for induction brazing and flame brazing. Used in electrical engineering, automotive industry and in

[35]

tool manufacture. Ag45Cu27.75Zn25Sn2.25

Ag-Cu-Zn

[][]

640/680

–

AG 104, L-Ag45Sn, Ag 2, BrazeTec 4576. Low temperature, free flowing. It is used in sanitary engineering. For soldering steel, copper and its alloys, nickel and its alloys. Good alternative to solder containing cadmium. Good absorption. It can be used for induction brazing and flame brazing. Used in construction, electrical engineering and automotive industries.

[35]

Industry.

List of hard solders

Ag45Cu27Zn25Sn3

Ag-Cu-Zn

344 [] [41]

–

BAg-36, Brasagem 452,

26,8

640/680

Silvaloy A45T, Mattisil

646/677

453. Low temperature, free flow. general purpose. Good replacement for alloys containing cadmium. Narrow melting range, suitable for manual or machine feeding into the joint. Good for narrow gaps. Clearance 0.025-0.15mm. Pale yellow color. Similar to AG 104. Maximum operating temperature 204 °C, short term 316 °C. To improve the corrosion resistance of stainless steel, use an alloy containing nickel, e.g. BAG-24. Ag45Cu25Zn26.8Sn3Si0.2

Ag-Cu-Zn

[42]

–

Matisil 453S. similar to

643/671

BAg-36, the addition of silicone promotes flow and creates smoother threads. Ag40Cu30Zn28Ni2

Ag-Cu-Zn

[]

–

BAG-4, Messing 403,

660/780

Argo welding 40N. slow flow. For tungsten carbide. For stainless steel food handling equipment. Economical alloy for brazing carbide tool tips to stainless steels. For brazing stainless steel, mild steel, cast iron, malleable iron and many non-ferrous alloys. Particularly well suited for stainless steel containers and food handling equipment. It tends to liquefy. Clearance from 0.1 to 0.25mm. Pale yellow color. Ag40Cu30Zn25Ni5

Ag-Cu-Zn

[]

–

Hartlöten 404. Para-Tungsten

660/860

Carbides for stainless steel.

0,2

List of hard solders

Ag40Cu30Zn28Sn2

Ag-Cu-Zn

345

650/710

[][][][43]

–

BAg-28, AG 105, L-Ag40Sn, Ag 3, Braze 402, Silvaloy A40T, Matti-sil 40Sn, BrazeTec 4076. Free flow. Fill gaps. Often chosen for its low temperature, good wetting and good flowability. Suitable for hand torch soldering where heating may be uneven. For steel, copper and copper alloys, nickel and nickel alloys; For joining ferrous, non-ferrous and mixed alloys with tight tolerances. General purpose, commonly used in refrigeration applications. It is used in sanitary engineering. Ideal for tight joints. Maximum operating temperature 204°C, short term 316°C. Gap 0.075-0.2mm. Pale yellow color. Good alternative to solder containing cadmium. Good absorption. It can be used for induction brazing and flame brazing. Used in construction, electrical engineering and automotive industries.

[35]

Industry.

List of hard solders

Ag34Cu36Zn27,5Sn2,5

Ag-Cu-Zn

346 []

–

630/730

AG 106, L-Ag34Sn,

27,5

2.5

Silvaloy A34T, BrazeTec 3476. Tin offers good wetting of difficult metals, e.g. tungsten carbide and stainless steel. For copper and its alloys, nickel and its alloys and iron alloys. The absence of lead and cadmium allows the use of long heating cycles. Can be used for flux-free controlled atmosphere soldering. It is mainly used for furnace soldering. Pale yellow color. Maximum operating temperature 204°C, short term 316°C. Good alternative to solder containing cadmium. Good absorption. It can be used for induction brazing and flame brazing. Use in electrical and automotive engineering.

[35]

Industrie. Ag30Cu36Zn32Sn2

Ag-Cu-Zn

[]

–

665/755

AG 107, L-Ag30Sn, BrazeTec 3076. For brazing steel, copper and its alloys, nickel and its alloys. Good alternative to solder containing cadmium. Good absorption. It can be used for induction brazing and flame brazing. Use in electrical and automotive engineering.

[35]

Industrie. Ag25Cu40Zn33Sn2

Ag-Cu-Zn

[] []

–

680/760

BAg-37, AG 108, brasagem

690/780

255, L-Ag25Sn, BrazeTec 2576. Inexpensive. For ferrous and non-ferrous alloys. For connections that do not require high impact strength or high ductility. For soldering steel, copper and its alloys, nickel and its alloys. Good alternative to solder containing cadmium. Good absorption. It can be used for induction brazing and flame brazing. Use in electrical and automotive engineering.

[35]

Industry.

List of hard solders

Ag24Cu43Zn33

Ag-Cu-Zn

347 [44]

–

Silvaloy A24.

688/810

BAg-20 low grade silver modification; a higher melting temperature gives greater mechanical strength at elevated temperatures. For copper, brass, silver, nickel and iron alloys. Commonly used for ferrous, non-ferrous and other close tolerance metals. Pale yellow color. Maximum operating temperature 260 °C, short term 371 °C. Ag56Cu19Zn17Sn5Ga3

Ag-Cu-Zn

[35]

–

BrazeTec 5662. Para

608/630

Brazing steel, copper and its alloys, nickel and its alloys, high-speed steel, diamond, tungsten carbide. Good alternative to solder containing cadmium. Good absorption, very low melting point. Ag63Cu24Zn13

Ag-Cu-Zn

Ag60Cu26Zn14

Ag-Cu-Zn

Ag44Cu30Zn26

Ag-Cu-Zn

[]

–

AG201

[]

–

AG202

[]

–

690/730

695/730

675/735

AG 203, L-Ag44, BrazeTec 4404. For brazing steel, copper and its alloys, nickel and its alloys. Good alternative to solder containing cadmium. Good absorption. It can be used for induction brazing and flame brazing. used in electrical engineering

[35]

and facilities.

Ga3

List of hard solders

Ag30Cu38Zn32

Ag-Cu-Zn

348 [] [] 695/770 [45] 677/766 [][46]

–

BAg-20, AG 204,

680/765

L-Ag30, Ag 4, Braze 300, Silvaloy A30, Matti-sil 30, BrazeTec 3075. Used

675/765

in the sanitary area. For steel and non-ferrous alloys with a melting point above 790 °C. For knife handles made of nickel silver. For electronic devices. Fill gaps; A wide melting range enables the production of fillets. For kits that come into contact with food and dairy products. General purpose soldering widely used to join copper, brass, bronze, nickel silver, steel and non-ferrous alloys. Suitable for dip soldering wires in electronics; the pour point corresponds to the melting point of borax, which is used as a flux to coat the surface of the molten metal in the pot. Pale yellow color. Maximum operating temperature 204°C, short term 316°C. Ag35Cu32Zn33

Ag-Cu-Zn

[]

–

BAg-35, Brasagem 351,

685/755

Silvaloy A35. Good all-purpose alloy. It can be used in the food industry. For ferrous and non-ferrous alloys. It is used in the electrical industry and for welding ship parts, lamps, tubes, band instruments, etc. Yellow-white color. Maximum operating temperature 204°C, short term 316°C. Ag25Cu40Zn35

Ag-Cu-Zn

[]

700/790

–

AG 205, L-Ag 25, BrazeTec 2500. For brazing steel, copper and its alloys, nickel and its alloys. Good alternative to solder containing cadmium. Good absorption. It can be used for induction brazing and flame brazing. Use in electrical and automotive engineering.

[35]

Industry.

List of hard solders

Ag20Cu44Zn36Si0,05–0,25

Ag-Cu-Zn

349 []

–

690/810

AG 206, L-AG 20,

0,25

BrazeTec 2009. For brazing steel, copper and its alloys, nickel and its alloys. Good alternative to solder containing cadmium. Good absorption. It can be used for induction brazing and flame brazing. Use in electrical and automotive engineering.

[35]

Industry. Ag12Cu48Zn40Si0.05-0.25

Ag-Cu-Zn

Ag5Cu55Zn40Si0,05–0,25

Ag-Cu-Zn

Ag50Cu15Zn16Cd19

Ag-Cu-Zn

Ag45Cu15Zn16Cd24

Ag-Cu-Zn

[]

–

AG207

0,25

[]

–

AG208

0,25

[]

AG301

fifteen

sixteen

[][] []

BAG-1, AMS 4769, AG

fifteen

sixteen

800/830

820/870

620/640

605/620

302, EasyFlo 45,

607/618

Mattibraze 45. Very ductile, good flow properties. High resistance. For ferrous, non-ferrous and dissimilar alloys. For narrow joints. Lowest melting point of Ag-Cu-Zn-Cd alloys. Suitable for most metals, e.g. steel, stainless steel, copper, nickel and their alloys. Not suitable for aluminum and magnesium. Narrow melting range, good capillary flow. Wide acceptance by industrial users. Pale yellow color. Maximum operating temperature 204°C (flashing 316°C).

List of hard solders

Ag50Cu15,5Zn16,5Cd18

Ag-Cu-Zn

350 [][47]

BOLSA-1a, AMS 4770,

15,5

16.5

625/635

Easy-Flo, Easy-Flo 50, Silvaloy 50, Mattibraze 50. Nearly eutectic. Same applications as BAg-1. Suitable for most metals, e.g. steel, stainless steel, copper, nickel and their alloys. Not suitable for aluminum and magnesium. For ferrous, non-ferrous and dissimilar alloys. Narrow melting range, no liquefaction. High fluidity, for strong connections. Very fluid, used where minimum soldering temperatures are required. When welding cast iron, graphite must be removed from the surface to ensure good wetting. May facilitate stress cracking of some alloys by embrittlement of the liquid metal; then a stress relieving anneal is required or the use of a higher melting point alloy which will not melt until the stress relieving temperature of the base metal is reached. Pale yellow color. Maximum operating temperature 204°C (flashing 316°C). Ag30Cu27Zn23Cd20

Ag-Cu-Zn

[] [48] 608/710 [49]

BAg-2a, Easy-Flo 30,

605/710

Silvaloy 30, Mattibraze 30. Similar to BAg-2,

605/745

more economical. For ferrous, non-ferrous and dissimilar alloys. For larger rooms where fillets are desired. For steel, stainless steel, copper, copper alloys, nickel, nickel alloys and combinations. For larger gaps where fillets are desired and the gaps are not uniform. Pale yellow color. Maximum operating temperature 204°C, short term 316°C.

List of hard solders

Ag25Cu35Zn26,5Cd13,5

Ag-Cu-Zn

351 []

BOLSA-27, Easy-Flo 25,

26,5

13.5

605/745

Silvaloy 25. Similar to BAg-2a, cheaper due to lower silver content; higher melting point and melting range result. For steel, stainless steel, copper, copper alloys, nickel, nickel alloys and combinations. It melts due to the soft state. For larger gaps where fillets are desired and the gaps are not uniform. Pale yellow color. Maximum operating temperature 204°C, short term 316°C. Ag25Cu40Zn33Sn2

Ag-Cu-Zn

[50]

–

BAg-37, Silvaloy A25T.

685/771

Similar to BAg-28, cheaper due to lower silver content; less active flux, higher melting point, higher melting range. For ferrous and non-ferrous alloys. For connections that do not require ductility and impact resistance. It is not ductile on cooling, it must be able to cool without mechanical and thermal shocks. Ag42Cu17Zn16Cd25

Ag-Cu-Zn

Ag40Cu19Zn21Cd20

Ag-Cu-Zn

Ag35Cu26Zn21Cd18

Ag-Cu-Zn

[]

AG303

sixteen

[]

AG304

BAG-2, AMS 4768, AG

610/620

595/630

[] [] 605/700 [51] 610/700

305, Easy Flo 35, Silvaloy 35, Mattibraze

607/701

35. Similar to BAg-1, cheaper. For ferrous, non-ferrous and dissimilar alloys. Free flow, for larger spaces where fillets are desired. For steel, stainless steel, copper, copper alloys, nickel, nickel alloys and combinations. Pale yellow color. Maximum operating temperature 204°C, short term 316°C. Ag30Cu28Zn21Cd21

Ag-Cu-Zn

[]

600/690

AG306

List of hard solders

Ag25Cu30Zn27,5Cd17,5

Ag-Cu-Zn

352 [] []

BAg-33, AG 307,

27,5

17.5

(Video) How to Braze Air Conditioning Copper

605/720

Simply Flo 25HC. Similar

640/715

for BAg-2a, cheaper. For ferrous, non-ferrous and dissimilar alloys. For larger rooms where fillets are desired. Ag21Cu35.5Zn26.5Cd16.5Si0.5

Ag-Cu-Zn

Ag20Cu40Zn25Cd15

Ag-Cu-Zn

Ag50Cu15,5Zn15,5Cd16Ni3

Ag-Cu-Zn

[]

AG308

35,5

26,5

16.5

[]

AG309

fifteen

BAG-3, AMS 4771, AG

15,5

610/750

605/765

[] [] 630/690 [52] 635/655

351, Easy-Flo 3, Silvaloy 50N, Mattibraze 50N. Meer

632/688

300 series stainless steel. For bonding tungsten carbide, beryllium copper and bronze to steel on aluminum. Introduced as a replacement for BAg-1a due to its higher corrosion resistance under certain conditions. Resistant to chloride corrosion. Used in marine applications. It is used in dairy facilities exposed to strong chlorine-based cleaning solutions. It is widely used for welding carbide tips in wood cutting, metal cutting and mining tools. Recommended for aluminum bronze as the nickel content compensates for the harmful effects of aluminum diffusion. Smooth during melting, most of the volume melts at the high end of the melting range. It can be used to fillet and fill large gaps. Fillets can be used to fill large gaps or distribute stress in the assembly. tendency to liquefaction. Pale yellow color. Maximum operating temperature 204°C (flashing 316°C). Clearance from 0.1 to 0.25mm. The cadmium-free alternative is BAg-24.

sixteen

0,5

List of hard solders

Ag44Cu27Zn13Cd15P1

Ag-Cu-Zn

353 []

Brazing 440. For electricity

fifteen

595/660

Copper-tungsten contacts and electrodes. Low melting point filling. Cd95Ag5

Cd-Ag

[]

Lot 053, Lot 53. A

340/395

high temperature solder For medium strong joints. It can join copper, brass and steel. It is used when the strength of the joint needs to be greater than can be achieved by welding and the temperature needs to be low, e.g. Thermostatic bellows that operate at temperatures too high to braze and need to be bonded below their annealing temperature. Excellent for small electric motors where overheating would cause the solder to fail. It is used for soldering gun parts instead of brazing because of its high resistance to alkaline solutions used for blackening and because of its greater resistance to high temperatures. Grey colour. Cu58Zn37Ag5

Ag-Cu-Zn

[]

–

Solder 051. Para-nichrome

840/880

resistance elements; The brazing temperature enables simultaneous stress relieving, which prevents grain boundary cracks. For simultaneous brazing and heat treatment of steels. For various ferrous and non-ferrous alloys. The zinc content and the high temperature required cause rapid alloying with non-ferrous metals, so the contact time of the liquid alloy with the base metals must be limited. In furnace brazing, the heating cycles must be short, otherwise the zinc can volatilize and leave small holes in the alloy. Brass yellow colour.

List of hard solders

Cu57Zn38Mn2Co2

354 [53]

Cu-Zn

–

Bronze F. for soldering

890/930

Tungsten carbide for steels. It is mainly used for rock drilling or where simultaneous heat treatment is required. Cu86Zn10Co4

[54]

Cu-Zn

–

Bronze D. Paralutes

960/1030

Tungsten carbide for steels. It is mainly used for rock drilling or where simultaneous heat treatment is required. Cu85Sn8Ag7

[]

Ag-Cu

–

Brazing 071. For vacuum

665/985

Systems As a low-temperature alternative to copper. For soldering with subsequent heat treatment. Cu85Sn15

Con-Sn

Cu60,85Ag36Si3Sn0,15

Ag-Cu

[]

–

Cut.

–

Developed as

60,85

fifteen

789/960

[]

0,15

Replacement of the Ag72Cu28 eutectic, with half the silver content and consequently lower material costs. Very similar mechanical, physical and application temperature properties. Cu53Zn38Cd18Ag9

Ag-Cu-Zn

[]

Solder 090. For copper

765/850

leagues, e.g. on band instruments. Also for brazing steels with simultaneous cyanide cementing. Cu45Zn35Ag20

Ag-Cu-Zn

[] [55]

–

Solder 202, Silvaloy A20.

710/815

It has a wide variety of uses

713/816

However, due to the high melting point, it is rarely used. Tight temperature matching for carbon steel heat treatment, enables brazing and heat treatment in one step. Generally higher strength than base metals. Maximum operating temperature 149 °C, short term 260 °C.

List of hard solders

Cu52,5Zn22,5Ag25

355 [] [56]

Ag-Cu-Zn

–

Braze 250. Join in

52,5

22,5

675/855

ferrous and non-ferrous

677/857

leagues. Tends to liquefy, rapid heating is preferred. The long melting range is advantageous for joints with large gaps. Specific use in jet engine compressors as a bearing surface material in friction seals. Brass yellow colour. Ag72Cu28

[][]

Ag-Cu

–

AG 401, BrazeTec 7200.

780

eutectic Good ductility, moderate temperature. Widespread. It can be used for welding metallic ceramics. It can be used for both flame and furnace brazing with protective atmosphere and vacuum. Silver can evaporate in a vacuum from 900°C. Ag60Cu30Sn10

Ag-Cu

[] [][] 600/720 []

–

AG 402, BAg-18,

600/730

BVAg-18, AMS 4773, Solder 603, Solder 604

602/718

(VTG quality for vacuum systems, with reduced volatile impurities), Cusilitin 10, BrazeTec 6009. For sealing vacuum tubes, for alloyed steels. It can weld some ferrous and non-ferrous alloys without flux. For marine heat exchangers (which come into contact with seawater at elevated temperatures where zinc would tend to leach). Some tendency to liquify. The tin content improves the wetting of ferrous alloys. Useful for sealing vacuum tube components and soldering without a flux controlled atmosphere. The white color. It can be used for both flame and furnace brazing with protective atmosphere and vacuum. Silver can evaporate in a vacuum from 900°C. Ag56Cu27.25In14.5Ni2.25

Ag-Cu

Ag55Cu30Pd10Ni5

Ag-Cu

[]

–

AG403

27.25

[]

–

Premabraze 550. Para

2.25

600/710

827/871

corrosion-resistant stainless steel seals.

a 14.5

List of hard solders

Ag85Mn15

Agriculture

356 [][]

–

960/970

BAg-23, AMS 4766, AG

fifteen

501, Braze 852. For high temperature applications where good strength is required. For complex chrome titanium carbides, stainless steel, stellite, inconel. For burner and furnace soldering. High melting point advantageous for subsequent heat treatments. It is used for carbide tools exposed to high temperatures. The white color. Can be used to infiltrate porous components produced by powder metallurgy ("infiltration brazing"); Silver's lubricity and resistance to friction make it attractive for bearings. It can be hardened by cold mechanical working.

[57]

Work. Ag49Cu16Zn23Mn7.5Ni4.5

Ag-Cu-Zn

Ag27Cu38Zn20Mn9,5Ni5,5

Ag-Cu-Zn

Ag25Cu38Zn33Mn2Ni2

Ag-Cu-Zn

[]

–

AG502

sixteen

7.5

4.5

[]

–

AG503

9.5

5.5

[]

–

BAg-26, Soldadura 252.

680/705

680/830

710/815

Economically. For carbide, stainless steel and steel. Ag90Pd10

[] []

Ag-Pd

–

Premabraze 901, Palsil

48,5

22,5

1002/1065

10. For stainless steels,

1025/1070

Nickel, molybdenum, tungsten and titanium fast soldering cycles. Ag48.5Pd22.5Cu19Ni10

Ag-Pd

910/1179

–

Palnikusil. Economically.

Ductile, for stainless steels. Wide spaces. Ni57.1Pd30Cr10.5B2.4

Pd-Ni

[]

–

Palnicro 30. Better

10.5

57.1

2.4

941/977

High temperature creep strength than BAu-4. Ni47Pd47Si6

Pd-Ni

[]

–

Palnisi-47. To enhance

810/851

High temperature creep strength than BAu-4. Ni50Pd36Cr10.5B3Si0.5

Pd-Ni

[]

–

Palnikro-36-M. To enhance

820/960

High temperature creep strength than BAu-4.

10.5

0,5

List of hard solders

Cu62,5Au37,5

357 [] []

have with

–

BAu-1, Premabraze 399.

62,5

37,5

990/1015

For copper, nickel, kovar,

991/1016

and metallic molybdenum-manganese ceramics. Au80Cu20

[]

Au-Con 891

–

[]

908/910

Build-2. Eutectic Loses ductility above 200°F.

[]

List of hard solders

Au80Sn20

358 []

280 Dollar

–

Au80, Indalloy 182, Premabraze 800, Orotin. Good wetting, high strength, low creep, high corrosion resistance, high thermal conductivity, high surface tension, zero wetting angle. Limited ductility. Suitable for step welding. The original alloy without flux, no flux required. It is used to attach metal chips and caps to semiconductor packages, such as Kovar caps for ceramic chip holders. Expansion coefficient that matches many common materials. Because the wetting angle is zero, pressure is required to form a void-free bond. Alloy of choice for joining gilded and gilded surfaces. Since some gold detaches from the surfaces during soldering, rendering the composition in a non-eutectic state (a 1% increase in Au content can increase the melting point by 30°C), subsequent desoldering is required

[58]

highest temperature

It forms a mixture of two brittle intermetallic phases,

[59]

AuSn and Au5Sn.

Fragile. Good wetting is generally achieved by using nickel finishes with a layer of gold on both sides of the joint. Fully tested through military standard environmental conditions. Good long-term electrical performance, history of

[60]

Reliability.

Under

Vapor pressure, suitable for vacuum work. Good ductility. Also classified as welding. Alloy with lower melting point and low vapor pressure.

List of hard solders

Au88Ge12

359 []

–

Au88, Indalloy 183,

Ge12

356

Premabraze 880, Georo. eutectic Low ductility. It is used for fixing dies of some chips. High temperatures can be detrimental to chips and limit reworkability. Vapor pressure too low. Ag90Ge10

Agriculture

[]

–

Low vapor pressure.

Ge10

651/790

without copper. Much lower thermal conductivity than silver. Low discoloration due to germanium content; Transparent germanium oxide passivation layer protects against silver sulphide formation. May be precipitation hardened. See also Argentium sterling silver. Ag82Pd9Ga9

Ag-Pd

[]

–

Capacity 9. Ductile.

Ga9

845/880

Corrosion resistant. For welding titanium to titanium and titanium to stainless steel. Cu62Au35Ni3

[][]

have with

–

BAu-3, Premabraze 127,

31,5

974/1029

Nicoro. For metallic nickel, kovar, stainless steel, molybdenum and molybdenum-manganese ceramics. Excellent wetting, low base metal erosion. Au35Cu31.5Ni14Pd10Mn9.5

[]

Au-PD

–

RI-46. for tungsten

971/1004

Carbide and super alloys.

9.5

List of hard solders

Au82Ni18

360 [] []

Oh me

–

BAu-4, BVAu-4, AU 105,

950

Vormabrasion 130,

955

Premabraze 131 (vacuum grade), AMS 4787, Nioro. eutetic Excellent moisturizer. stretchy. Oxidation resistance surpasses palladium containing alloys. High mechanical resistance at high temperatures. Nickel gray color. For stainless steel, tungsten, all common refractory irons and nickel alloys, Inconel X, A286, Kovar and similar alloys. Not normally used for copper or silver base alloys; Flux point near the melting point of silver and bonds well with copper. Low penetration of the base metal, suitable for welding thin parts, e.g. thin-walled tubes or vacuum tubes. Does not produce severe intergranular penetrations characteristic of boron nickel braze alloys. Widely used in the nuclear industry except in regions of high neutron flux and in contact with liquid sodium or potassium. Oxidation and incrustation resistance up to 815 °C. Brazing in an inert atmosphere or under vacuum. Au82In18

451/485

–

Au82, Indalloy 178.

at 18

she 3

she 2

High temperature welding, extremely hard, very stiff. Au60Cu37In3

have with

[]

–

Repeat 60. Bottom weld

860/900

Temperature als andere Au-Cu. Au20Cu68In2

[]

have with

–

I spend 20 Cheaper

975/1025

Replacement for BAu-3 and other gold-rich copper and gold alloys. Au72Pd22Cr6

[]

Au-PD

–

Chrono. for soldering

975/1000

Diamond for stainless steel Minimizes chromium depletion in base metals. High corrosion resistance.

List of hard solders

Au75Ni25

Oh me

361 []

–

UA 106. Oxidation

73,8

26.2

950/990

Strength exceeds palladium containing alloys. High mechanical resistance at high temperatures. Au73.8Ni26.2

[]

Oh me

–

Nioro-Ni von Solo

980/1010

Tolerances for stainless steel and super alloys. Excellent process. Au81.25Ni18Ti0.75

Oh me

[]

–

Nioro-Ti.

81,25

0,75

945/960

hard-to-wet metals. Au70Ni30

[]

Oh me

–

ductile, Oxidation

960/1050

resistant. flow force. Excellent moisturizer. Au75Cu20Ag5

have with

[]

–

Premabraze 051, Silcoro

885/895

75. Narrow melting range, suitable for step soldering. Au80Cu19Fe1

have with

Au62,5Cu37,5

have with

Au60Ag20Cu20

Au-Ag-Cu

[]

–

AU101

[]

–

AU102

37,5

62,5

[]

–

Premabraze 408, Silcoro

905/910

930/940

835/845

60. Narrow melting range, good for step soldering. Au81.5Cu16.5Ni2

have with

[]

–

Premabraze 409, Nicoró

16.5

81,5

62,5

37,5

Sixty-five

955/970

80. Remains ductile when solid. Low vapor pressure. For copper, nickel, molybdenum manganese. Au50Cu50

have with

[]

–

Preamble 402nd paragraph

955/970

Metallized copper, nickel, kovar and molybdenum manganese ceramics. Au37.5Cu62.5

[] []

have with

–

AU 103. For copper,

980/1000

Nickel, Kovar u

985/1005

Metallized molybdenum manganese ceramic. Au35Cu65

[]

have with

–

Preamble 407. Paragraph

990/1010

Metallized copper, nickel, kovar and molybdenum manganese ceramics. Au30Cu70

have with

Ni36Pd34Au30

Au-Pd-Ni

Au70Ni22Pd8

Au-Pd-Ni

[]

–

AU104

[]

–

Bau-5.

[] [61]

–

BAu-6, AMS 4786,

995/1020

1135/1166

1007/1046

Premabraze 700, Palniro

1005/1037

7. High strength and ductility. For stainless steels and super alloys.

List of hard solders

Au50Pd25Ni25

362 []

Au-Pd-Ni

–

BVA Au-7, AMS 4784,

fifteen

1102/1121

Premabraze 500, Palniro 1. High strength, good oxidation resistance. Suitable for joining super alloys. Like Au30Pd34Ni36, lower soldering temperature. Au30Pd34Ni36

[62]

Au-Pd-Ni

–

AMS 4785, Palniro 4.

1135/1169

High resistance. Corrosion resistant. For super alloys. Au92Pd8

[]

Au-Pd

–

BAu-8, BVAu-8, Paloro.

1199/1241

Ductile, not rusty. Wet tungsten, molybdenum, tantalum and super alloys. Au25Cu31Ni18Pd15Mn11

[]

Au-Pd-Ni

–

Palnicurom 25. Para

1017/1052

Tungsten Carbide and Super Alloys. Au25Cu37Ni10Pd15Mn13

[]

Au-Pd-Ni

–

Palnicurom 10. Para

970/1013

Tungsten Carbide and Super Alloys. Ag68Cu27Pd5

Ag-Cu

[]

–

BVAg-30, pre-embraced

807/810

680, Palcusil 5. Narrow melting range. For Kovar and Molybdenum-Manganese punches, it's better to wet here than Cusil. Ag59Cu31Pd10

Ag-Cu

[]

–

BVAg-31, pre-hosted

824/852

580, Palcusil 10. (Ag58Cu32Pd10?) Excellent for vacuum tight connections. For soldering nickel, kovar, copper and molybdenum-manganese. Ag54Pd25Ni21

Ag-Pd

[] []

–

BAG-32, BVAg-32,

899/949

Premabraze 540, Palcusil

900/950

25. Similar to Au-Ni, cheaper, lower density. Does not weaken the Kovar. Pd65Co35

[]

–

BVPd-1, Premabraze

Sixty-five

1229/1235

180. Narrow melting range, low erosion of substrates. Ag54Cu21Pd25

Ag52Cu28Pd20

Ag65Cu20Pd15

[]

–

DP101.

[]

–

DP102.

[][]

–

PD 103, Prembraze 265, 20

Sixty-five

fifteen

900/950

875/900

850/900

Palcusil 15. For copper-free metallized ceramics, stainless steel, Kovar and manganese/molybdenum.

List of hard solders

Ag67,5Cu22,5Pd10

Ag58,5Cu31,5Pd10

Ag68,5Cu26,5Pd5

Pd60Ni40

363 []

–

PS 104.

22,5

67,5

[]

–

DP105.

31,5

58,5

[]

–

PS 106.

26,5

68,5

–

PD 201, Palni. eutectic

830/860

825/850

805/810

[]

1235

It does not flow well due to the high Ni content. Wet tungsten, nickel, stainless steel, super alloys. Ag75Pd20Mn5

[] []

Ag-Pd

–

PD 202, Palmansil 5. For

1000/1120

Wolframcarbid u

1008/1072

Super Liga. Cu82Pd18

Cu-Pd

Ag95PD5

Ag-Pd

Ag95Al5

[]

–

PD203

–

PD204

–

stretchy. for titanium

1080/1090

[]

970/1010

[]

780/830

Ligen. Au75,5Ag12,4Cu9,5Zn2,5Ir0,1

[63]

–

Wieland Porta Optimum 9.5

2.5

12.4

75,5

Ir0.1

14.5

12.4

Ir0.1

1,5

73,5

6.2

88,7

Ir0.1

Ir0.3

860/882

880. Tooth welding. Yellow COLOUR. Au73Ag12.4Zn14.5Ir0.1

[64]

–

The Wieland Gate is the best

680/700

710. Dental welding. Yellow COLOUR. Au73.5Ag25Zn1.5

[Sixty-five]

–

Wieland Bio Porta 1020.

960/1010

dental welding. Yellow COLOUR. Au88.7Ag3Zn6.2Pt2Ir0.1

[66]

–

The Wieland Gate is the best

830/890

900. Tooth welding. Yellow COLOUR. Au89Zn5.7Pt5Ir0.3

[67]

–

The Wieland Gate is the best

5.7

850/930

940. Tooth welding. Yellow COLOUR. Au49.7Ag32.5Zn4.5Pd13Ir0.3

[68]

–

Wieland Porta-1090W.

4.5

32,5

49,7

Ir0.3

17.5

1.9

34,9

0,5

980/1090

dental welding. The white color. Au80Ag17.5Sn0.2In0.3Pt1.9Ir0.1

[69]

–

Wieland PortaIP V-1.

1015/1055

0,2

Ir0.1In0.3

dental welding. Yellow COLOUR. Au64Ag34.9In0.6Pt0.4Ir0.1

[70]

–

Wieland PortaIP V-2.

1015/1030

Ir0.1In0.6

dental welding. Yellow COLOUR. Au62Ag17Cu7Zn6In5Pd3

[71]

–

Wieland Europa M-1.

17.5

71,5

710/770

dental welding. Yellow COLOUR. Au62Ag22Cu4Zn12

[72]

–

Wieland W-2 European.

720/750

dental welding. Yellow COLOUR. Au71.5Ag17.5Zn10Pt1

[73]

–

Wieland Porta OP M-1.

750/810

dental welding. Yellow COLOUR.

List of hard solders

364 [74]

Au68Ag19Zn12Pt1

–

Porta Wieland ON W-2.

710/765

verkauft dental. Cor amarillo. Ni73,25Cr14Si4,5B3Fe4,5C0,75

[] []

Ni-Cr

–

980/1060

BNi-1, AMS 4775, NI

977/1038

101, high temperature 720.

4.5

73,25

4.5

73,25

4.5

73,25

4.5

C0.75

Relatively aggressive to the base metal. good flow. Good corrosion properties. Limited applications, typically brazing heavier sections. Recommended for light exertions in high temperatures. Distance from 0.05 to 0.12 mm. When joining martensitic stainless steels, fillet cracks occur on cooling (due to the volumetric deformation caused by the martensitic transition of the base metal) and can reduce joint fatigue. This can be avoided by time-consuming stress relief heating just above the martensitic transition of the base metal, or by using BNi-1A, a reduced-carbon version that reduces the modulus of the filler alloy enough to prevent cracking.

[]

Education. Ni73.25Cr14Si4.5B3Fe4.5

[] []

Ni-Cr

–

BNi-1A, AMS 4776, NI

980/1070

101A, high temperature 721.

977/1077

<0.06%C. Low carbon version of BNi-1, used where the carbon content of BNi-1 would be harmful. Low flow, slower than BNi-1. Oxidation resistant seals. It is used in some gas turbine applications. Clearances of 0.05-0.15mm. Ni73.25Cr7Si4.5B3Fe3C0.75

[]

Ni-Cr

–

NI 102. Nearly eutectic.

970/1000

Alloy for general use. Relatively low temperature. Good flow at fast heating rates. Gaps from 0.03 to 0.10 mm.

C0.75

List of hard solders

Ni82.4Cr7Si4.5Fe3B3.1

Ni-Cr

365 [75] []

–

BNi-2, AMS 4777,

82,4

3.1

4.5

92,5

4.5

94,5

3.5

966/1040

High Temperature 820. <0.06%C

971/999

Good flow, good fillets, low base metal erosion. Widespread. For food handling components, medical devices and aircraft parts. For furnace soldering. Ni92.5Si4.5B3

[] []

–

BNi-3, AMS 4778, NI

980/1040

103, high temperature 910. <0.5%

982/1066

Fe, < 0.06% C. Relatively fluid, liquid. chrome free. Limited use in special applications. Good for narrow and long joints. Relatively insensitive to the dryness of the furnace atmosphere. Ni94.5Si3.5B2

[]

–

BNi-4, AMS 4779, NI

970/1000

104, Hi-Temp 930. <1.5% Fe, <0.06% C. Rather hypoeutectic version of BNi-3. Wider use than BNi-3. relatively slow. relatively stretchy. Often more resilient than other nickel-based metals. Spacing 0.05-0.10mm. For stainless steels as well as cobalt and nickel alloys. Suitable for welding thin sections, eg on chemical devices and engine parts. Ni71Cr19Si10

Ni-Cr

[]

–

BNi-5, AMS 4782, NI

1080/1135

105. High melting point, reduced only by silicon. Good flow, limited void fill. Avoid fillets, these tend to be crack starters. Avoid larger rooms. Small, hard seals can be made that are very resistant to oxidation. Gaps from 0.03 to 0.1 mm.

List of hard solders

Ni89P11

366 [] []

cut

–

BNi-6, NI 106, High temp

875

932. < 0,06 % C. Eutecticum.

877

Extremely fluid, therefore limited bridge. Good behavior in nitrogenous atmospheres. It can be bathed from electrolytic baths. It is used for low voltage connections. Not much used. Can be used to braze stainless steel with OFHC or phosphorus deoxidized copper. Intervals of about 0.03 mm. For stainless steels as well as cobalt and nickel alloys. Suitable for welding thin sections, eg on chemical devices and engine parts. It offers high temperature properties and good corrosion resistance at relatively low processing temperatures. Ni76Cr14P10

[] []

Ni-Cr-P

–

BNi-7, NI 107, High temp

890

933. < 0,06 % C. Eutecticum.

888

Chrome containing version of the BNi-6. Originally developed for brazing parts for nuclear reactor cores. Extended flow at higher temperatures. Good results for low voltage hermetic connections. It is used, for example, in immersion heaters and wiring harnesses for thermocouples. Suitable for continuous furnace brazing in a dissociated ammonia atmosphere. Apertures less than 0.03 mm. It is widely used for welding honeycomb structures and thin-walled pipes. Used in nuclear applications due to the lack of boron. The chromium content offers better high temperature properties and better corrosion resistance than BNi-6.

List of hard solders

Ni65,5Si7Cu4,5Mn23

367 []

–

NI 108. Special Use,

4.5

65,5

980/1010

for very thin cuts. Very low diffusion, low interaction with the base metal. The volatility of manganese requires special handling when vacuum brazing. Apertures less than 0.03 mm. Ni81.5Cr15B3.5

Ni-Cr

[]

–

Nr. 109. Eutecticum. <1.5%

fifteen

81,5

3.5

1055

Trust. Good initial penetration. Special use in the aerospace industry. Good choice for gap filler powder. Ni62.5Cr11.5Si3.5B2.5Fe3.5C0.5W16

[]

Ni-Cr-W

–

NI 110. Moderate Flow.

11.5

sixteen

3.5

62,5

2.5

3.5

C0.5

10.5

12.1

3.25

67,25

2.7

3.8

C0.5

970/1105

Use in the aerospace industry. It almost always requires follow-up. Gaps from 0.1 to 0.25 mm. Ni67.25Cr10.5Si3.8B2.7Fe3.25C0.4W12.1

[]

Ni-Cr-W

–

NI 111. Reduced Tungsten

970/1095

Version NI 110, improved flow. It can have better fatigue strength than other nickel alloys. Ni65Cr25P10

[]

Ni-Cr-P

–

DAY 112. Reich and Chrom

Sixty-five

880/950

Version of NI 107, similar process; not eutectic but penetrates well. Excellent corrosion resistance in many weak electrolytes. Co67.8Cr19Si8B0.8C0.4W4

[]

Co-Cr

–

1120/1150

CO 101. Suitable for gas

67,8

0,8

turbine operation. In some cases it can withstand temperature fluctuations above the soldering temperature. Suitable for new and

[]

parts repaired by brazing. Co50Cr19Ni17Si8W4B0.8

Co-Cr

100€

rein

[76]

–

BCo-1, AMS 4783.

–

pure metal. very stretchy,

1107/1150

[]

1064

wets most metals.

100

C0.4

List of hard solders

Ag100

rein

368 962

–

BAg-0, BVAg-0, soldering

100

999. Pure metal. League VTG. For semiconductor ceramics. Good mechanical properties, compatible with most metals, low vapor pressure, excellent melt flowability. It is mainly used for soldering reactive metals, e.g. beryllium and titanium. Even with a wet iron, it doesn't bind significantly. Due to the relatively high cost, it is rarely used alone. pd100

rein

[]

pure metal.

100

1555

High temperature brazing of refractory metals. pt100

rein

1767

–

very high temperature

100

Welding. For refractory metals for high temperature applications. 100 cu

rein

[]

–

pure metal; COM101

1085

(99.90%), CU 102 or CDA 102 (99.95%), CU 103 (99%), CU 104 (99.90%, 0.015-0.040% P), BCu-1 or CDA 110 (99, 99%). It flows freely. Can be used for pressure connections. For iron alloys, nickel alloys and copper-nickel alloys. BVCu-1x is OFHC, vacuum grade, for furnace brazing of steels, stainless steels and nickel alloys. Oxygen-containing copper is not compatible with hydrogen-containing atmospheres and becomes brittle. Cheaper than silver but requires higher processing temperatures and is prone to oxidation. It is used in flux-free vacuum brazing of stainless steels. High fluidity, low base metal removal, very good steel wetting. Relatively soft, which benefits stress relief but affects joint strength.

100

List of hard solders

Ni100

369

rein

–

pure metal. rarely used

100

because of the high melting point. It is used to join molybdenum and tungsten for high temperature applications. Ti100

rein

1670

–

Fe40Ni38B18Mo4

–

pure metal.

100 4

Amorphous metal. To

Brazing and soft magnetic applications. Crystallization at 410 °C. maximum service

[77]

Temperature 125 °C.

[]

Ti60Cu20Ni20

–

Recommended for soldering 20

?/950

titanium alloys; Composition similar to many engineering titanium alloys. Ti54Cr25V21

[]

attachment

–

High temperature. closely

V21

?/1500

melting range. Excellent ceramic wettability; Penetrates and seals surface pores and cracks, increasing fracture toughness. Ti91.5Si8.5

[]

–

High temperature. welding

91,5

8.5

Temperature 1400°C. Can be used for soldering molybdenum. Ti70V30

[]

–

High temperature. welding

V30

Temperature 1650°C. Can be used for soldering molybdenum. V65Nb35

[]

–

High temperature. welding

V65Nb35

Temperature 1870°C. Can be used for soldering molybdenum. Nb97.8B2.2

Nb80Ti20

Pt85W11B4

[]

–

High temperature. It could be

2.2

Nb97.8

used for welding tungsten. –

High temperature. It could be

WOMEN 80th

used for welding tungsten. –

High temperature. articulation

Reflux temperature 2200°C. It can be used for soldering tungsten. W75Os25

[]

–

Temperature too high. Requires very intensive heating, e.g. Electric arc. It can be used for soldering tungsten.

Os25

List of hard solders

W47Mo50Re3

370 –

[]

Temperature too high.

Te3

Requires very intensive heating, e.g. Electric arc. It can be used for soldering tungsten. Mo95Os5

–

[]

Temperature too high.

Os5

Requires very intensive heating, e.g. Electric arc. It can be used for soldering tungsten.

[]

Ti70Cu15Ni15

–

for super alloys and

fifteen

Zr20

Zr83

902/932

Technical Ceramics. Available as an amorphous film.

[]

Ti60Zr20Ni20

–

for super alloys and

848/856

Technical Ceramics. Available as an amorphous film.

[]

Zr83Ni17

–

welding titanium

961

leagues. Available as an amorphous film.

[]

Zr56V28Ti16

–

welding titanium

sixteen

1193/1250

leagues. Available as an amorphous film. Ag57Cu38Ti5

attachment

[]

–

775/790

active league. This can be used

26,7

68,8

4.5

for brazing ceramics, e.g. silicone nitride. Titanium forms an interfacial layer with Si3N4, producing TiN,

[]

TiSi and Ti5Si3.

For

Brazing of technical ceramics. Available as an amorphous film. Ag68.8Cu26.7Ti4.5

attachment

[]

780/900

–

Ticusil. active league. Can be used for ceramic soldering, e.g. silicon nitride. Titanium forms a boundary layer with Si3N4, whereby TiN, TiSi,

[]

and Ti5Si3.

for soldering

Technical Ceramics. Available as an amorphous film.

Zr56V28

List of hard solders

Ag72.5Cu19.5In5Ti3

371 [78]

attachment

–

BrazeTec CB1. attachment

19.5

72,5

26,5

70,5

34.2

1.8

730/760

To turn on. Can be used for brazing ceramics, metal ceramics, graphite, diamond, corundum, sapphire, ruby. You need at least 850°C to wet the ceramic, higher temperatures improve the wetting. For use under argon or vacuum, silver can evaporate in a vacuum from 900°C. Ag96Ti4

[78]

attachment

–

BrazeTec CB2. attachment

970

attachment

[78]

–

BrazeTec CB4. attachment

780/805

attachment

[78]

–

BrazeTec CB5. attachment

780/810

To turn on. Can be used for brazing ceramics, metal ceramics, graphite, diamond, corundum, sapphire, ruby. Similar to Cusil-ABA. You need at least 850°C to wet the ceramic, higher temperatures improve the wetting. For use under argon or vacuum, silver can evaporate in a vacuum from 900°C.

List of hard solders

Ag98,4Ti0,6

attachment

372 [78]

–

BrazeTec CB6. attachment

98,4

0,6

948/959

To turn on. It can be used for soldering silicon nitride. (Someone check the composition, one percent of something is missing.) For use under argon or vacuum, silver can be evaporated in vacuo. Au97.5Ni0.75V1.75

attachment

Au96,4Ni3Ti0,6

attachment

Cu92,75Si3Al2Ti2,25

attachment

Au82Ni15,5V1,75Mo0,75

attachment

Ag92.75Cu5Al1Ti1.25

attachment

[]

–

Oro-ABA-V.

97,5

[]

–

Gold-ABA.

96,4

–

Kupfer-ABA.

[]

–

Nioro-ABA.

[]

–

Prata-ABA.

0,75

V1.75

1045/1090

0,6

1003/1030

[]

92,75

2.25

958/1024

0,75

15,5

V1.75

940/960

92,75

1.25

860/912

BRAND COMPLIANT - Specially designed to meet the standard of sterling silver used in jewelry. zinc free. Preforms made by rapid solidification. Ag63Cu35.25Ti1.75

attachment

Ag63Cu34.25Sn1Ti1.75

attachment

Ag59Cu27.25In12.5Ti1.25

attachment

Ti67Ni33

attachment

Ti70Cu15Ni15

attachment

Pd54Ni38Si8

[]

–

Cusil-ABA.

35,25

1,75

[]

–

Cusin-1-ABA.

34.25

1,75

[]

–

Incusil-ABA.

27.25

1.25

[]

–

Tine 67.

[]

–

ticks

[]

–

For soldering stainless steel

780/815

775/805

am 12.5

605/715

fifteen

942/980

fifteen

910/960

830/875

Steels, super alloys and hard metals. ta60w30zr10

attachment

–

Can be used for soldering graphite. For use at temperatures up to

[]

2700 Grad.

Ta60Zr10

List of hard solders

Referenzen [1] AL 718 Füllmetall für das Aluminiumlöten (http://www.matweb.com/search/DataSheet.aspx?MatGUID=073c6ecdeb844133b32beb023fafe5f9) [2] AL 719 Füllmetall für das Aluminiumlöten (http://www.matweb .com/search/DataSheet.aspx?MatGUID=a1330fcba9114a43bb50ca8ff9808538) [3] AL 802 Aluminiumhartlot Metall (http://www.matweb.com/search/DataSheet.aspx?MatGUID=a0112e9baa9b4155a85526d8a5a7e1e7) [6] Silvaloy Hartlot (http://18M/www.matweb.com/search/DataSheet.aspx?MatGUID=3a7c6587cad1484b98c650c2a4555 ) 7] Matti-sil 18Si cadmiumfreies Lot (http://www.matweb.com/search/DataSheet.aspx?MatGUID=c094d5c69b7f4b50a1d9d517) [8] SIL-FOS Copper 18 Alloy /match (http:// www .matweb.com/search/ Data Sheet.aspx?MatGUID=2d38b7e2323d4f33a3916976d6c54375) [9] Silvaloy 6 Lotlegierung (http :/ / www. matweb. com/search/datasheet. aspx?MatGUID=0c9102917c7b42029f5982b17a8058b2) [10] Matti-phos Fluxing / Copper Forz (http: matweb. com/search/ DataSheet. aspx?MatGUID=b0013b73dc684e07946295733d5ec5ed) [11] / Phosphorus Alloy (http: www.mat.com.com.com. DataSheet.aspx?MatGUID=e05a318f44704428a91501edab9) [12] Mattiforphos 2 Alloy Copper Fluxless Hartlöten (http://www.matweb.com/search/DataSheet.aspx?MatGUID=f80bee42c4404a41b07b308291c04ed9) [13] Lotlegierung (Silvaloy) http:// www.matweb.com/search/DataSheet.aspx?MatGUID=e870ba2f9fd040bc9a68e2bcf7057f13) [14] SIL-FOS 2 Silber/Phosphorlegierung (http://www.matweb.com/search/DataSheet.com/search/ DataSheet.aspx? MatGUID=f5b3309f780645f7af ada38bb4d816d16) [15] ] Silvalite Hartlot (http://www.web.com/search/DataSheet.aspx?MatGUID=65f4d3ad7dad4f87b2adfb04ea80fa5c) [17] Silvabraze 33830 /Brazing/Alloy www.matweb.com/search/search/search/search/search/ datasheet.aspx?MatGUID=4c1777b931a645eca1d1167d0de6f70b) [18] Silvaloy 0 Lötlegierung / matweb/ suche / www. / DataSheet.aspx?MatGUID=3fba36c0af4c40d79851bcf08576958a) [19] Silvacap 35490 Brazing Alloy (webhttp.com/search/DataSheet.aspx?MatGUID=7ef55bc8e2da475f8625c393d3a) by Metal2FLO70FLO contribution to tin and copper brazing/web. /DataSheet.aspx?MatGUID=4a2e3300c76542269922130987b682cd ://www.Insis.cz/classification.php?cat=21&subcat=34#[23]HANDY HI-TEMP 095 Carbide Lotlegierung (http://www.matweb.com/search/DataSheet.aspx?MatGUID=889b863019d6423e8cb267fed3d2d3a8 ) [24] Silvaloy X55 Lotlegierung (http://www.matweb.com/search/DataSheet.aspx?MatGUID=29aa54ae936f4a3db69843e47ff8dcae) [25] Journal of Nuclear MaterialsDirect: -Step Brazing Process for Joining CFC Compounds to Copper and Copper Alloys (http://www.sciencedirect.com/science?_ob=ArticleURL& _udi=B6TXN-4PFW6JC-D& _user=10& _coverDate=02/29/2008& _rdoc=1& _fmt =high& _orig=search& _sort=d& _docanchor=& view= c& _acct=C000050221& _version=1& _urlVersion=0& _use rid=10& md5=fe2113591dc57022f569268d15afc2f2) [26] ScienceDirect – Journal of Nuclear Materials: One-Step Brazing Process for CFC Monoblock Joints and Mechanical Testing (http://www.sciencedirect.com/science?_ob= ArticleURL& _udi= B6TXN-4WK440G -2& _user=10& _coverDate=01.09.2009& _rdoc=1& _fmt=high& _orig=search& _sort=d& _docanchor=& view=c& _acct =C000050221& _version=1& _urlVersion=0& _userid=10& md5 1f11e261a609f709f 8] http://www. matweb. com/search/datasheet. aspx?MatGUID=772518c55fbe4860b1099491e3a6a735) [28] Silvalo A4 Lotlegierung (http://www.matweb.com/search/DataSheet.aspx?MatGUID=66fc2af22c214bf4a92ceb28a544bec5) [29] Matti-sil 45 Cadmium-Free Lotlegierung Alea www. matweb.com/search/ DataSheet.aspx?MatGUID=de6aee37d97943e991be34e18b3245ac) [30] Silvaloy Hartlot A54N (http://www.matweb.com/search/DataSheet.aspx?MatGUID=9794a5643e884062bac5e43a06c1f562) auf Cadmiumbasis (http://www .matweb.com/search/DataSheet.aspx?MatGUID=936e346b8740457d9659b9af8e7fbe0c) [32] BRAZE 495 Carlobi / www. .aspx ?MatGUID=0466c35f87334e9ea278de02db095fee) [33] Argo-braze 49LM Silberlötlegierung zum Hartlöten mit Wolframcarbid (http://www.matweb.com/search/DataSheet.aspx? MatGUID=1ed9ece76b614742a3e3a10e6ec73ciumSis) FreeCam Alloy (http://www .matweb.com/search/DataSheet.aspx?MatGUID=be6d6025ce174457838942f3236df298) [35] http://www. darauf bestehen. cz/ Bewertung. php?cat=21&subcat=22#

373

List of Solder Alloys [36] Silvaloy Solder Alloy B72 (http://www.matweb.com/search/DataSheet.aspx?MatGUID=79e9263d65514894b9b91136c5cd6e75) [38] Lithobraze 925 Cadmium Free Silver Based Solder (http ://www .matweb.com/ search/datasheet.aspx?matguid=cc0bc234c69d4b6bad4327106aef336c&ckck=1) [39] BRAZE 630 cadmium-free silver-based solder (http://www.matweb.com/search/ DataSheet .aspx?MatGUID=85ac77fd68b9484b909b15261275 ) 40] Silvaloy Alot Hart (http: //www.matweb.com/search/DataSheet.aspx?MatGUID=ae30fa44c8514ce3b422b2548b49c980] Matti cadmium free braze -sil 4 www.matweb.com search./DataSheet.aspx?MatGUID= c2006c653087457c8d95b1cd9b7f3bce) [42] Matti-sil cadmium free braze 4533bce) http://www.matweb.com/search/DataSheet.aspx?MatGUID=12e1c669cb6a414a8399e039662) // .m atweb.com/search/DataSheet.aspx?MatGUID.aspx =b75c67b854ba46f6ae262c040cf3a882) [44] Sil Valoy A24 braze (http: //www.web.com/search/datasheet.aspx?MatGUID=61d0d9f5465a43ea9e53f2d78f4a0f0a) [45] A complete one Assortment of high quality brazing alloys, silver, solders and fluxes (http://www.thermadyne.com/IM_Uploads/DocLib_2678_66-2826.pdf) [46] Mattisil 30 cadmium free solder (http://www.matweb.com/search/DataSheet. aspx?MatGUID=a0fdd85b391944838f22595c3549bf32) [47] Mattibraze 50 Cadmium-Containing Silver Lot (http://www.matweb.com/search/datatasheet.aspx? Matguid = C00FF2A5359A450492ACABC480B776D1) [48] SILVALOY 30 HOT SOLDER (http://www.matweb.com/search/ DataSheet. [50] Silvaloy A25T HOT SOLDER (http://www.matweb.com/search/ DataSheet.aspx?MatGUID= e52072d0fd1b4860afc5b385b614b5 Silvaloy Hartlot /32072d0fd1b4860afc5b385b614b5 Silvaloy Hartlot /3/ dataSheet/ search http:5) .com/? MatGUID=6164bdf5b25a41 118ad801fa7bba4eda) [52] EASY FLO 3 Carbide Brazin g Legierung (http://www. matweb. com/search/datasheet . aspx?MatGUID=4fdaa8f9cc8346b2ac0c8c855c198d7d) [53] F high-temperature bronze solder (tungsten carbide http://www.matweb.com/search/DataSheet.aspx?MatGUID=c9a1a6ce2bb84368af2aea7ed178c13e) [54] D hard solder high-temperature soldering tungsten carbidewww.löten matweb.com/search/DataSheet.aspx? MatGUID=989dbe032e0c4c679bfa1eac4ef52a8c) [55] Silvaloy A20 braze (http://www.matweb.com/search/DataSheet.aspx?MatGUID=c6afc124280c453eb14c9e 762c7f6b7b) [56] Cadmium free solder.BRAZE 250 Silver Base (http://www.web.com/search/DataSheet.aspx?MatGUID=9 89f71b6d9444f919cbef104b682bda8]gold) [56] Tin: the only eutectic solder alloy (http://www.indium.com/ _dynamo/ download.php?docid=298) [61] Au-Pd-Ni (AMS 4786) filler metal for gold soldering ( http://www.matweb.com/search/ DataSheet.aspx ?MatGUID=a68557d61ef844f2bbb3f2b594b3a3de ) [62] BAu-5 (AMS 4785) Hard Solder in Gold (http://www.matweb.com/search/DataSheet.aspx? Mat GUID=4f53a027f6cf4d2faac4e76a7b4986f5) [63] Wieland Porta Optimum 880 Welding (http://www.matweb.com/search/datasheet.aspx? MatGUID=6f3253def7234846bebf361f) [ ] Wieland Porta Oprimum 710 / / www.matweb.com/search/ DataSheet.aspx?MatGUID=312f43ac0e99489991cccba9363a893c) [65] Wieland Bio Porta 1020 / www. matweb.com/search/DataSheet. aspx?MatGUID=7842114a585b446c85aa8f66426e3b91) [66] Wieland Porta Optimum 900 Solder (http://www.matweb.com/search/DataSheet.aspx?MatGUID=c7213 Optia1589984008a14eland Porta Optimum 900 [4e9] Wiumad7.] /4mum / DataSheet.aspx?MatGUID=74620b6bb40b4da98aa02bdb7935bf0d) [68] Wieland Port 1090-W Soldering (http://www.matweb.com/search/DataSheet.aspx?MatGUID=fcfbb83e633c4bbf474bab6fe900) Wieland Port IP V-1 Soldering (http: / /www.matweb.com/search/DataSheet.aspx?MatGUID=d5d4ce1d1e5a4fdebf5afdc0c3f522c7) [70] Wieland Solder IP Port V-2 (http://www.matweb.com/search/DataSheet.aspx?MatGUID= fa0dcb7481df4e628db3802b62440a7f) [ 71 ] Wieland Auropal M-1 Welding (http://www.matweb.com/search/datasheet.aspx?MatGUID=8d293f5567e746a3a1f37db9f3fb4 Welding Wieland2) [72] (http:///www.matweb.com./DataSheet.aspx ? MatGUID=58107aa56f6d4d7e860c1991c47845c4) [73] Wieland Welding ( OP:/1 / www.web.com/search/DataSheet.aspx?MatGUID=8f26be6f864d42ffb1 2e8db574c32a78) [74] Wieland Port OP W-2 Welder ( http://www. matweb. com/search/DataSheet. aspx? MatGUID=268cf1bb22ff421aa4ddd7001b063f51) [75] BNi-2 7AMS solder (7) Solder for brazing based on (http://www.matweb.com/search/DataSheet.aspx?MatGUID=c64846fc5cf049de83a0c02f376393b6) [76] BCo -1 ( AMS 4783 ) Nickel-based solder (http://www.matweb.com/search/DataSheet.aspx?MatGUID=1a75661b63544bbe89352fbb504404ab) [77] Goodfellow Iron 40/Nickel 38/Boron 18 Alloy ( http://www.matweb.com/search /DataSheet.aspx?MatGUID=9344c7b3297d4056bd09cac4c14)

374

List of hard solders [78] http://www. insist. cz/ rating. php?cat=21& subcat=35#

Induction Brazing Induction brazing is a process in which two or more materials are joined by induction heating with a solder that has a lower melting point than the base materials. In induction heating, ferrous materials are generally rapidly heated by the electromagnetic field created by alternating current from an induction coil.

Materials and Applications “Induction brazing is suitable for many metallic materials and magnetic materials heat up more easily. With ceramic materials, heating occurs more by conduction from surrounding metal parts or through the use of a susceptor” (Sue Dunkerton, 1). According to Ambrell Group Application Labs talking about filler metals: Silver is commonly used for induction brazing because of its low melting point. Eutectic silver and copper solders have melting temperatures between 1100°F and 1650°F. Aluminum solder, the least common, has a melting point of 1050°F to 1140°F. Copper solder, the cheapest, has a melting point of 1300°F to 2150°F. (p1) Putty can be applied by hand, but due to more semi-automated production, pre-filled joint is more commonly used to speed up the process and get a smoother joint.

Benefits There are specific reasons for using induction heating in industrial brazing. These include selective heating, better bond quality, reduced oxidation and acid cleaning, faster heating cycles, more consistent results, and suitability for mass production.

Selective Heating Induction heating can be tailored to deliver heat to very small areas within tight production tolerances. Only the areas of the part that are very close to the joint are heated; the rest of the part remains untouched. Since there is no direct contact with the part, there is no risk of breakage. Fastener life is significantly increased by eliminating repetitive heat exposure problems (such as distortion and metal fatigue). This advantage becomes particularly important in high temperature soldering processes. With an efficient coil design, careful clamping, and even positioning of the parts, it is possible to deliver heat to different areas of the same part at the same time.

Better Quality Joints Induction heating creates clean, leak-proof joints and prevents putty from flowing into areas where it shouldn't. This ability to create clean, controllable connections is one of the reasons why induction soldering is widely used for high-precision, high-reliability applications.

Rust Reduction and Cleaning Flame Heating in normal atmosphere causes rust, chipping and carbon deposits on parts. Parts cleaning has traditionally required the application of fluxes to weaken the joints and expensive acidic cleaning baths. Batch vacuum furnaces solve these problems, but have their own significant limitations due to their size, low efficiency, and lack of quality control. Induction brazing reduces oxidation and costly cleaning requirements, especially when using a quench cycle.

375

Induction soldering

376

Fast Heating Cycles Because the induction heating cycle is very short compared to flame brazing, more parts can be processed in the same amount of time and less heat is lost to the environment. “An induction brazing system quickly delivers highly localized heat to minimize part warpage and warping. Brazing in a controlled vacuum or inert atmosphere can significantly improve overall part quality and eliminate costly part cleaning processes” (Induction Atmospheres, 1).

Consistent Results Induction brazing is a highly repeatable process because variables such as time, temperature, alloy, fixture and part placement are highly controllable. The internal power supply of the RF power supply can be used to control cycle time, and temperature control can be performed using pyrometers, visual temperature sensors, or thermocouples. Processes with medium to high production runs of the same parts often use an automated parts handling system to further improve consistency and maximize productivity. Brazing and induction brazing are most often done outdoors, but they can also be done in a controlled atmosphere if needed to keep parts sparkling clean and free from oxidation. Induction brazing generally works best with two pieces of similar metal. Dissimilar metals can also be joined using induction heating, but this requires special attention and techniques. This is due to differences in resistivity, relative magnetic permeability, and thermal expansion coefficients of the materials. (p1)

General Temperatures and Times According to Turnkey Induction Heating Solutions: Process

Hour

Temperature (°F)

Brazing of stainless steel pipes

20 seconds 1330°F

Soldering orthodontic stainless steel parts

1 Second