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Boriding
Boriding, also called boronizing, is the process by which boron is added to a metal or alloy. It is a type of surface hardening. In this process boron atoms are diffused into the surface of a metal component. The resulting surface contains metal borides, such as iron borides, nickel borides, and cobalt borides, As pure materials, these borides have extremely high hardness and wear resistance. Their favorable properties are manifested even when they are a small fraction of the bulk solid.Helmut Kunst, Brigitte Haase, James C. Malloy, Klaus Wittel, Montia C. Nestler, Andrew R. Nicoll, Ulrich Erning and Gerhard Rauscher "Metals, Surface Treatment" in Ullmann's Encyclopedia of Industrial Chemistry, 2006, Wiley-VCH, Weinheim. Boronized metal parts are extremely wear resistant and will often last two to five times longer than components treated with conventional heat treatments such as hardening, carburizing, nitriding, nitrocarburizing or induction hardening. Most borided steel surf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iron Boride
Iron boride refers to various inorganic compounds with the formula FexBy. Two main iron borides are FeB and Fe2B. Some iron borides possess useful properties such as magnetism, electrical conductivity, corrosion resistance and extreme hardness. Some iron borides have found use as hardening coatings for iron. Iron borides have properties of ceramics such as high hardness, and properties of metal properties, such as thermal conductivity and electrical conductivity. Boride coatings on iron are superior mechanical, frictional, and anti-corrosive. Iron monoboride (FeB) is a grey powder that is insoluble in water. FeB is harder than Fe2B, but is more brittle and more easily fractured upon impact. Formation Thermochemical Formation Iron borides can be formed by thermochemically reacting boron rich compounds on an iron surface to form a mixture of iron borides, in a process known as boriding. There are a number of ways of forming boride coatings, including gas boriding, molten salt bo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boron
Boron is a chemical element with the symbol B and atomic number 5. In its crystalline form it is a brittle, dark, lustrous metalloid; in its amorphous form it is a brown powder. As the lightest element of the ''boron group'' it has three valence electrons for forming covalent bonds, resulting in many compounds such as boric acid, the mineral borax, sodium borate, and the ultra-hard crystals of boron carbide and boron nitride. Boron is synthesized entirely by cosmic ray spallation and supernovae and not by stellar nucleosynthesis, so it is a low-abundance element in the Solar System and in the Crust (geology), Earth's crust. It constitutes about 0.001 percent by weight of Earth's crust. It is concentrated on Earth by the water-solubility of its more common naturally occurring compounds, the borate minerals. These are mined industrially as evaporites, such as borax and kernite. The largest known deposits are in Turkey, the largest producer of boron minerals. Elemental b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surface Hardening
Case-hardening or surface hardening is the process of hardening the surface of a metal object while allowing the metal deeper underneath to remain soft, thus forming a thin layer of harder metal at the surface. For iron or steel with low carbon content, which has poor to no hardenability of its own, the case-hardening process involves infusing additional carbon or nitrogen into the surface layer. Case-hardening is usually done after the part has been formed into its final shape, but can also be done to increase the hardening element content of bars to be used in a pattern welding or similar process. The term face hardening is also used to describe this technique, when discussing modern armour. Hardening is desirable for metal components that are subject to sliding contact with hard or abrasive materials, as the hardened metal is more resistant to surface wear. However, because hardened metal is usually more brittle than softer metal, through-hardening (that is, hardening the m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metal
A metal (from Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typically ductile (can be drawn into wires) and malleable (they can be hammered into thin sheets). These properties are the result of the ''metallic bond'' between the atoms or molecules of the metal. A metal may be a chemical element such as iron; an alloy such as stainless steel; or a molecular compound such as polymeric sulfur nitride. In physics, a metal is generally regarded as any substance capable of conducting electricity at a temperature of absolute zero. Many elements and compounds that are not normally classified as metals become metallic under high pressures. For example, the nonmetal iodine gradually becomes a metal at a pressure of between 40 and 170 thousand times atmospheric pressure. Equally, some materials regarded as metals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alloy
An alloy is a mixture of chemical elements of which at least one is a metal. Unlike chemical compounds with metallic bases, an alloy will retain all the properties of a metal in the resulting material, such as electrical conductivity, ductility, opacity (optics), opacity, and lustre (mineralogy), luster, but may have properties that differ from those of the pure metals, such as increased strength or hardness. In some cases, an alloy may reduce the overall cost of the material while preserving important properties. In other cases, the mixture imparts synergistic properties to the constituent metal elements such as corrosion resistance or mechanical strength. Alloys are defined by a metallic bonding character. The alloy constituents are usually measured by mass percentage for practical applications, and in Atomic ratio, atomic fraction for basic science studies. Alloys are usually classified as substitutional or interstitial alloys, depending on the atomic arrangement that forms the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boride
A boride is a compound between boron and a less electronegative element, for example silicon boride (SiB3 and SiB6). The borides are a very large group of compounds that are generally high melting and are covalent more than ionic in nature. Some borides exhibit very useful physical properties. The term boride is also loosely applied to compounds such as B12As2 (N.B. Arsenic has an electronegativity higher than boron) that is often referred to as icosahedral boride. Ranges of compounds The borides can be classified loosely as boron rich or metal rich, for example the compound YB66 at one extreme through to Nd2Fe14B at the other. The generally accepted definition is that if the ratio of boron atoms to metal atoms is 4:1 or more, the compound is boron rich; if it is less, then it is metal rich. Boron rich borides (B:M 4:1 or more) The main group metals, lanthanides and actinides form a wide variety of boron-rich borides, with metal:boron ratios up to YB66. The properties of this g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heat Treatment
Heat treating (or heat treatment) is a group of industrial, thermal and metalworking processes used to alter the physical, and sometimes chemical, properties of a material. The most common application is metallurgical. Heat treatments are also used in the manufacture of many other materials, such as glass. Heat treatment involves the use of heating or chilling, normally to extreme temperatures, to achieve the desired result such as hardening or softening of a material. Heat treatment techniques include annealing, case hardening, precipitation strengthening, tempering, carburizing, normalizing and quenching. Although the term ''heat treatment'' applies only to processes where the heating and cooling are done for the specific purpose of altering properties intentionally, heating and cooling often occur incidentally during other manufacturing processes such as hot forming or welding. Physical processes Metallic materials consist of a microstructure of small crystals called "gr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Superalloy
A superalloy, or high-performance alloy, is an alloy with the ability to operate at a high fraction of its melting point. Several key characteristics of a superalloy are excellent mechanical strength, resistance to thermal creep deformation, good surface stability, and resistance to corrosion or oxidation. The crystal structure is typically face-centered cubic (FCC) austenitic. Examples of such alloys are Hastelloy, Inconel, Waspaloy, Rene alloys, Incoloy, MP98T, TMS alloys, and CMSX single crystal alloys. Superalloy development has relied heavily on both chemical and process innovations. Superalloys develop high temperature strength through solid solution strengthening and precipitation strengthening from secondary phase precipitates such as gamma prime and carbides. Oxidation or corrosion resistance is provided by elements such as aluminium and chromium. Superalloys are often cast as a single crystal—while grain boundaries may provide strength at low temperatures, th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inconel
Inconel is a registered trademark of Special Metals Corporation for a family of austenitic nickel-chromium-based superalloys. Inconel alloys are oxidation-corrosion-resistant materials well suited for service in extreme environments subjected to pressure and heat. When heated, Inconel forms a thick, stable, passivating oxide layer protecting the surface from further attack. Inconel retains strength over a wide temperature range, attractive for high-temperature applications where aluminium and steel would succumb to creep as a result of thermally-induced crystal vacancies. Inconel's high-temperature strength is developed by solid solution strengthening or precipitation hardening, depending on the alloy.INCONEL alloy 718 Special Metals Corporation Inconel alloys are typical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hastalloy
Haynes International, Inc., headquartered in Kokomo, Indiana, is one of the largest producers of corrosion-resistant and high-temperature alloys. In addition to Kokomo, Haynes has manufacturing facilities in Arcadia, Louisiana, and Mountain Home, North Carolina. The Kokomo facility specializes in flat products, the Arcadia facility in tubular products, and the Mountain Home facility in wire products. In fiscal year 2018, the company's revenues were derived from the aerospace (52.1%), chemical processing (18.2%), industrial gas turbine (12.0%) and other (12.3%) industries. The company's alloys are primarily marketed under the Hastelloy and the Haynes brands. They are based on nickel, but also include cobalt, chromium, molybdenum, tungsten, iron, silicon, manganese, carbon, aluminum, and/or titanium. History The company was founded by Elwood Haynes in 1912 in Kokomo, Indiana, as Haynes Stellite Works. Haynes had recently received a patent for a metal he created, which he named Stel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boron Carbide
Boron carbide (chemical formula approximately B4C) is an extremely hard boron–carbon ceramic, a covalent material used in tank armor, bulletproof vests, engine sabotage powders, as well as numerous industrial applications. With a Vickers hardness of >30 GPa, it is one of the hardest known materials, behind cubic boron nitride and diamond. History Boron carbide was discovered in the 19th century as a by-product of reactions involving metal borides, but its chemical formula was unknown. It was not until the 1930s that the chemical composition was estimated as B4C. Controversy remained as to whether or not the material had this exact 4:1 stoichiometry, as, in practice the material is always slightly carbon-deficient with regard to this formula, and X-ray crystallography shows that its structure is highly complex, with a mixture of C-B-C chains and B12 icosahedra. These features argued against a very simple exact B4C empirical formula. Because of the B12 structural unit, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steel
Steel is an alloy made up of iron with added carbon to improve its strength and fracture resistance compared to other forms of iron. Many other elements may be present or added. Stainless steels that are corrosion- and oxidation-resistant typically need an additional 11% chromium. Because of its high tensile strength and low cost, steel is used in buildings, infrastructure, tools, ships, trains, cars, machines, electrical appliances, weapons, and rockets. Iron is the base metal of steel. Depending on the temperature, it can take two crystalline forms (allotropic forms): body-centred cubic and face-centred cubic. The interaction of the allotropes of iron with the alloying elements, primarily carbon, gives steel and cast iron their range of unique properties. In pure iron, the crystal structure has relatively little resistance to the iron atoms slipping past one another, and so pure iron is quite ductile, or soft and easily formed. In steel, small amounts of carbon, other ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
