Applications

Closeup of a tungsten filament inside a halogen lamp.

Because of its ability to produce hardness at high temperatures and its high melting point, elemental tungsten is used in many high-temperature applications.^[15] These include light bulb, cathode-ray tube, and vacuum tube filaments, as well as heating elements and nozzles on rocket engines.^[3] The high melting point also makes tungsten suitable for aerospace and high temperature uses which include electrical, heating, and welding applications, notably in the gas tungsten arc welding process (also called TIG welding).

Due to its conductive properties, as well as its relative chemical inertia, tungsten is also used in electrodes, and in the emitter tips of field emission electron-beam instruments, such as focused ion beam (FIB) and electron microscopes. In electronics, tungsten is used as an interconnect material in integrated circuits, between the silicon dioxide dielectric material and the transistors. Additionally, it is used in the manufacture of metallic films, which replace the wiring used in conventional electronics with a coat of tungsten (or molybdenum) on silicon.^[16]

In World War I, steel was put under restricted commercial uses, so Victor developed a tungsten gramophone needle. Called the "Tungs-tone" stylus (as Victor called it), this needle could withstand about 50 to 100 uses before wearing out the record. Victor claimed the needle could be used 300 times, but this would likely cause excessive wear/damage to a record. Victor stated that the needle be tested in the run-off (near the label) grooves and be rotated a quarter turn periodically, and then be tested in the run-off grooves. Victor stated that a Tungs-tone should be a used one for playing a record.^[17]

The electronic structure of tungsten makes it one of the main sources for X-ray targets,^[18] and also for shielding from high-energy radiations (such as in the radiopharmaceutical industry for shielding radioactive samples of FDG). Tungsten powder is used as a filler material in plastic composites, which are used as a nontoxic substitute for lead in bullets, shot, and radiation shields. Since this element's thermal expansion is similar to borosilicate glass, it is used for making glass-to-metal seals.^[7]

The hardness and density of tungsten are applied in obtaining heavy metal alloys. A good example is high speed steel, which may contain as much as 18% tungsten.^[19] Superalloys containing tungsten, like Hastelloy and Stellite, are used in turbine blades and wear resistant parts and coatings. Applications requiring its high density include heat sinks, weights, counterweights, ballast keels for yachts, tail ballast for commercial aircraft, and as ballast in high level race cars in series, such as NASCAR and Formula 1. It is an ideal material to use as a bucking bar for riveting, where the mass necessary for good results can be achieved in a small, easy to wield bar. In armaments, tungsten, usually alloyed with nickel and iron or cobalt to form heavy alloys, is used in kinetic energy penetrators as an alternative to depleted uranium but may also be used in cannon shells, grenades and missiles to create supersonic shrapnel. High-density alloys of tungsten may be used in darts (to allow for a smaller diameter and thus tighter groupings) or for fishing lures (tungsten bead heads allow the fly to sink rapidly). Some types of strings for musical instruments are wound with tungsten wires. Its density, similar to that of gold, allows tungsten to be used in jewelry as an alternative to gold or platinum.^[3] Its hardness makes it ideal for rings that will resist scratching, and are hypoallergenic and will not need polishing, which is especially useful in designs with a brushed finish.^[20]

Tungsten chemical compounds are used in catalysts, inorganic pigments (e.g. tungsten oxides), and also as high-temperature lubricants (tungsten disulfide). Tungsten carbide (WC) is used to make wear-resistant abrasives and cutters and knives for drills, circular saws, milling and turning tools used by the metalworking, woodworking, mining, petroleum and construction industries^[2] and accounts for about 60% of current tungsten consumption.^[21] Tungsten oxides are used in ceramic glazes and calcium/magnesium tungstates are used widely in fluorescent lighting. Crystal tungstates are used as scintillation detectors in nuclear physics and nuclear medicine. Other salts that contain tungsten are used in the chemical and tanning industries.^[7]

Lately, tungsten is used for jewelry because of its longevity and extremely high durability.