The properties of tungsten powder have direct influence on the production of tungsten materials and the quality of tungsten powder metallurgical products, especially on the purity and particle size. Tungsten powder is classified according to its purity, particle size and different uses.
Tungsten powder is the main raw material for processing powder metallurgy tungsten products and tungsten alloys. Pure tungsten powder can be made into wire, rod, tube, plate and other processing materials and certain shape products. Tungsten powder mixed with other metal powders can be made In particular tungsten alloys, such as tungsten-molybdenum alloy, tungsten-rhenium alloy, tungsten-copper alloy and high density tungsten alloy. Another important application of tungsten powder is to make tungsten carbide powder, and then to prepare cemented carbide tools, such as Turning tools, milling cutters, drills and dies.
It is a gray ferrous metal with metallic luster (body-centered cubic crystallization). Melting point 3400 C. Boiling point 5555 C. The hardness of tungsten is the hardest in metal. The hardness of sintered tungsten bars is 200-250, and that It is slightly soluble in nitric acid, sulfuric acid and aqua regia, but insoluble in water, hydrofluoric Acid and potassium hydroxide.
There are two variants of tungsten, A and B. At standard temperature and atmospheric pressure, type A is a stable body-centered cubic structure. Type B tungsten can only occur in the presence of oxygen. It is stable below 630 C and converts to Tungsten a above 630 C, and this process is irreversible.
In addition to the requirement of impurity content, the oxygen content of tungsten powder should be controlled within a certain range. The particle size of commonly used tungsten powders is generally 2-10 micron in average Feldspar size. Tungsten powder is polygonal particle shape. Addition, the specific surface area, bulk density and shaking density of tungsten powder also change in a certain range.