Tungsten is extracted from wolframite (named after the German wolfram for the element), scheelite (calcium tungstate, CaWO4), and other minerals. Tungsten and its alloys are used in high-temperature structural materials, electrical elements, especially light filaments, and instruments requiring thermally compatible glass-to-metal seals. When added to steel, tungsten increases its strength. It is alloyed other metals to make "superalloys" which have special physical properties of high strength and heat resistance. Some of the applications for such superalloys are in turbine engines for jet aircraft and energy generation. Other alloys bearing tungsten are used for armaments, heat sinks, radiation shielding, weights and counterweights, wear-resistant parts and coatings.
Tungsten is relatively inert, and resembles molybdenum. Tungsten carbide is used to make cutting tools and wear-resistant tools for metalworking, drilling for oil and gas, mining, and construction.
Tungsten was discovered in 1758 by Axel Fredrik Cronstadt; in 1781 Carl Wilhelm Scheele isolated a tungsten oxide, and in 1783 the Spanish chemists (and brothers) Fausto and Juan Jose de Elhuyar, working in Vergara, first separated tungsten from the mineral wolframite. The name comes from the Swedish tung sten, meaning "heavy stone".
Tungsten carbideAn extremely hard, inert, gray powder used for making abrasives, dyes, drill tips, and armor-piercing shells. Tungsten carbide (WC) is made by heating tungsten and lamp-black (powdered carbon) in an electric furnace. Relative density 15.6; melting point 2,780°C (5,036°F).
Related category INORGANIC CHEMISTRY
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