| Tungsten is also called Wolframite. In
1779 Peter Wolfe examined the mineral wolframite and concluded that it
must have substance in it. Scheele, in 1781 found that a new
acid could be made out of Wolframite. Tungsten was discovered
in 1783. It was originally known as wolfram because the mineral,
wolframite, played an important role in the discovery of this element.
Some German journals still prefer to refer to tungsten by its original
name.
Pure tungsten is relatively soft and can be cut
with a hacksaw. But small amounts of impurities render the metal
hard and brittle. Therefore, its ductility depends a lot on the purity
of the samples. Tungsten has the highest melting point (3410oC)of
all the elements. At high temperature, when most other metals vaporize,
tungsten glows with a brilliant white light. Because of its strong
electrical conductivity, tungsten is well-known as a metal used for making
filaments in incandescent light bulbs.
Tungsten is also an alloying element in steel.
Tungsten steel is noted for its strength and stability at high temperatures.
Nozzles for rocket engines are made from tungsten steel. Tungsten
is also a component of cathodes in electronic devices and of welding electrodes.
Tungsten carbide, WC, is used in machine tools and metal-cutting dies.
Various alloys are also used in electric circuitry. |
