The Knowledge of Tungsten

Aug. 22, 2010 - PRLog -- Although tungsten is more and more popular, people are also not familiar with it. Thus, I will give the detailed description about tungsten. At first, we will talk about the characteristics of the tungsten.
Characteristics:
Tungsten is a very hard, dense, silvery-white, lustrous metal that tarnishes in air, forming a protective oxide coating. In powder form tungsten is gray in color.
The metal has the highest melting point of all metals, and at temperatures over 1650 oC also has the highest tensile strength. Pure tungsten is ductile, and tungsten wires, even of a very small diameter, have a very high tensile strength.
Tungsten is highly resistant to corrosion. It forms tungstic acid (H2WO4), or wolframic acid from the hydrated oxide (WO3) and its salts are called tungstates, or wolframates.
Tungsten is one of the five major refractory metals (metals with very high resistance to heat and wear). The other refactory metals are molybdenum, tantalum, rhenium and niobium.
Uses:
Tungsten and its alloys are widely used for filaments in older style (not energy saving) electric bulbs and electronic tubes. It is used for making heavy metal alloys because of its hardness. Tungsten is used for high-temperature applications such as welding.
High speed steel (which can cut material at higher speeds than carbon steel), contains up to 18% tungsten.
Tungsten carbide (WC or W2C) is extremely hard and is used to make drills. It is also used for jewelry because of its hardness and wear resistance.
Discovered:
In 1779 Peter Woulfe deduced the existence of a new element - Tungsten - from his analysis of the mineral wolframite (an iron manganese tungstate mineral). Tungsten was isolated by Fausto and Juan Jose de Elhuyar in 1783 by reduction acidified wolframite with charcoal. The element name comes from the Swedish words 'tung sten', meaning heavy stone. The chemical symbol, W, comes from the original name of the element, Wolfram.
Harmful effects:Tungsten is considered to be of low toxicity.
Source:
Tungsten is not found free in nature. The principal ores of tungsten are wolframite (an iron manganese tungstate) and scheelite (calcium tungstate, CaWO3). Comercially, the metal is obtained by reducing tungsten oxide with hydrogen or carbon
Isotopes:
Tungsten has 33 isotopes whose half-lives are known with mass numbers from 158 to 190. Of these, three are stable: 180W, 182W, and 186W.
To sum up, we know the tungsten’s characteristics, uses, discovery, source and istopes. In my opinion, you may have a better understanding of tungsten.