Tungsten crucible chemical properties
Tungsten crucible is one of the tungsten metal products. It is mainly divided into sintering molding (applied to powder metallurgy technology), stamping molding, and spinning type. It is formed by turning tungsten rods (generally smaller in size) and welded into various shapes. It is made of pure tungsten plates, tungsten sheets and pure tungsten rods processed by corresponding processes. Tungsten crucible can be used in vacuum inert gas below 2600 degrees. Tungsten has a high melting point and boiling point, good high-temperature strength, wear resistance and corrosion resistance, high thermal conductivity, small thermal expansion coefficient, and good hardenability. Tungsten crucibles are widely used in rare earth smelting, quartz glass, electronic spraying, crystal growth and other industries.
Tungsten is a rare high-melting point metal that can improve the high-temperature hardness of steel. It belongs to the VIB group in the sixth period (the second longest period) of the periodic table of elements. Tungsten is a silver-white metal that looks like steel. Tungsten has a high melting point, low vapor pressure, and low evaporation rate. The chemical properties of tungsten are very stable. It does not react with air and water at room temperature. Without heating, any concentration of hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid and aqua regia has no effect on tungsten. When the temperature rises to 80°-100 At °C, among the various acids mentioned above, except for hydrofluoric acid, other acids have a weak effect on tungsten. At room temperature, tungsten can be quickly dissolved in a mixed acid of hydrofluoric acid and concentrated nitric acid, but it does not work in an alkaline solution. In the presence of air, molten alkali can oxidize tungsten into tungstate. In the presence of oxidants (NaNO3, NaNO2, KClO3, PbO2), the reaction to form tungstate is more violent. It can combine with chlorine, bromine, iodine, carbon, nitrogen, sulfur, etc. at high temperatures, but not with hydrogen.
