Tungsten

Thanks to its exceptional refractory property and high structural behaviors, tungsten is the most promising base for materials and products that operate under high temperatures and radiation levels.

Tungsten is marked by maximal interatomic bond strength, a high melting temperature (3420 ºС), a high density of 19.3 g/cm³, a high tensile strength, heat conductivity, hardness (HV30 >460), resistance to creep and stress rupture (significantly higher than with molybdenum, tantalum, or niobium at a temperature, for example, of 1100 °С). Compared to molybdenum, pure tungsten has a higher recrystallization temperature, of approximately 1350 °С, a 4-5 times less vapor pressure and vaporization rate and a lower thermal expansion coefficient (4.2 х 10^-6 at 20 °С) and electric resistance (0.05 х 10^-6 Om х m).

Since 1965, JSC POLEMA has been actively developing production of high-purity tungsten powder and rolled stock, as well as tungsten-based composite materials.

The cutting-edge powder metallurgy technologies used at JSC POLEMA ensure that our tungsten is largely free from metallic and interstitial impurities (C, N, O, H) and has a small-grained structure necessary for application in the electronics manufacturing industry and as a heat-resistant construction material in electrical engineering and other devices that work at extremely high temperatures.

JSC POLEMA produces a wide range of tungsten products that boast outstanding properties and meet the most stringent requirements.

Our tungsten products are made from in-house manufactured tungsten powder.

Tungsten oxide with a mass fraction of WO₃ 99.99 % is used as the starting material, which guarantees a high level of purity in the resulting powder and, as a result, high purity in the products made from it.

Tungsten-based products include the following:

Tungsten powder
Tungsten sheets, plates and sputtering targets
Tungsten crucibles
Tungsten-based composites W-Cu, W-Ni-Cu

Typical chemical composition of tungsten powder PW 99.95 used in production
Element	Ppm	Element	Ppm	Element	Ppm
Li	< 0.01	Cr	≤ 2	Ru	< 0.01
Be	< 0.01	Mn	≤ 0.1	Cd	< 0.1
B	< 0.1	Fe	≤ 15	In	< 0.01
C	≤ 30	Co	< 0.2	Sn	< 0.2
N	≤ 11	Ni	≤ 12	Sb	≤ 1.6
O	≤ 170	Cu	≤ 1	Cs	< 0.1
Na	≤ 6	Zn	< 0.1	Ba	< 0.1
Mg	≤ 0.3	Ge	< 0.01	Ta	≤ 4
Al	≤ 7	As	≤ 7	W	matrix
Si	< 5	Se	< 0.1	Pt	< 0.1
P	< 10	Rb	< 0.1	Tl	< 0.1
K	≤ 10	Sr	< 0.1	Pb	≤ 0.3
Ca	≤ 6	Y	< 0.01	Bi	< 0.1
Sc	≤ 0.1	Nb	≤ 1	U	≤ 2.2
Ti	≤ 0.6	Mo	≤ 38	S	≤ 30
V	≤ 0.3	Rh	< 0.01	S	≤ 30
Ga, Zr, Pd, Ag, Te, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Re, Ir, Au, Th in each					<0.05

Various equipment for high-temperature vacuum and hydrogen furnaces (heat screens, heaters, trays, racks, and other fastening components) are made from pure tungsten, as are crucibles for melting corundum in sapphire growing technologies, crucibles for thermal vaporization of substances in technologies for vacuum deposition of thin films, plasmatron electrodes, igniter systems in internal combustion engines and devices for measuring the concentration of acid solutions in electrochemical processes.

Tungsten sputtering targets made from high-grade tungsten are used to deposit thin barrier films during the metallization of semiconducting components of integrated circuits.

Heat-resistant parts operating under extremely high temperatures and intense gas erosion are made from tungsten and its alloys.

Tungsten's low vapor pressure allows it to be used at high temperatures (up to 2300 °C) as an electron emitter in thermoionic convertors.

In the nuclear power industry, tungsten is used in the form of screens for weakening the flow of radiation, ensuring the functionality of elements facing the plasma under high radiation and thermal-cycle stresses (the divertor in a thermonuclear reactor).

Porous, sintered tungsten is a promising material for use in ionizers in plasma-ion engines.