Tungsten General Electric's attempt to patent it, overturning granted in 1913 to William D. Coolidge. Tungsten Tungsten, or wolfram, is a chemical element with symbol W and atomic number 74. The name "tungsten" comes from the former Swedish name for the tungstate mineral "scheelite", "tung sten" or "heavy stone". Tungsten is a rare metal found naturally on Earth almost exclusively combined with other elements in chemical compounds rather than alone. It was identified as a new element in 1781 and first isolated as a metal in 1783. Its important ores include wolframite and scheelite. The free element is remarkable for its
Melting-point depression and thermal properties. This article focuses on nanoparticles because researchers have compiled a large amount of size-dependent melting data for near spherical nanoparticles. Nanoparticles are easiest to study due their ease of fabrication and simplified conditions for theoretical modeling. The melting temperature of a nanoparticle decreases sharply as the particle reaches critical diameter, usually < 50 nm for common engineering metals. Figure 1 shows the shape of a typical melting curve for a metal nanoparticle as a function of its diameter. Melting point depression is a very important issue for applications involving nanoparticles, as it decreases the functional range of