Pure Tungsten, WK, WTh, WCe and WLa

Tungsten exhibits the highest operating temperature of all metals at around 3420°C. Its physical, chemical, and mechanical properties can be widely varied by the adding of suitable alloying elements. Pure and doped tungsten is used in the lighting industry, electronics, medical applications and thin-film technology as well as for welding electrodes and in the construction of high-temperature furnaces.

Tungsten as a pure metal exhibits the following properties:

• High melting point of 3420 °C (3693K)

• Low vapor pressure

• High hot strength

• Low thermal expansion

• High thermal conductivity

• High Young‘s modulus

• High density

• High shielding capacity of radiation

• High corrosion resistance against acids and molten metals

• high recrystallization temperature

WTh20 (thoriated Tungsten)

Doping with a combination of aluminium potassium silicate and thoria (ThO2) gives rise to increased high-temperature sag resistance and a reduction of the electron work function. This makes   these materials ideally suited for highly loaded cathodes. WVMT, which is doped with 1 weight percent ThO2, can be drawn to wire with diameter ≤ 0.5 mm. The more highly doped WVMWT is used for larger-diameter rods. 

WC20 (Ceriated Tungsten)

WC20 is an alternative to the WT20 lamp and welding electrode. Doping with 2 weight-percent cerium oxide reduces the electron work function and improves the ignition behaviour and the lifetime by reducing the rate of arcing erosion. 

WL10 / WL15 (Lanthanated Tungsten)

Doping with 1 - 1.5 weight % lanthanum oxide increases the creep strength and recrystallization temperature in comparison to pure tungsten. In addition the oxide particles in the structure help to eliminate the poor machinability associated with pure tungsten. The addition of lanthanum oxide also signifi cantly reduces the electron work function. WL10 is preferred for machined components in a wide variety of applications (e.g. ion source components, lamp electrodes) whereas WL15 is used for welding electrodes.