What is Tungsten Powder
Tungsten powder is pure tungsten in powder, apparent black powder. The regular tungsten powder fearture with 2~10um, 99.90% or 99.95%. Tungsten powder used as material for tungsten product usually.
Chemical properties: Purity. The purity of tungsten powder is of particular importance in PM manufacturing of tungsten metal, since during subsequent sintering further purification through evaporation is only possible to a certain extent. The demand for purity of tungsten powder has increased steadily during the last three decades. Considerable improvements in hydrometallurgy have led to concentrations fairly below 10 µg/g for most of the elements. This trend with time can be demonstrated by comparing today's usual specifications with those given in the last book on "Tungsten" by Yih and Wang, published in 1979.
Physical properties. The relevant physical properties are average particle size, particle size distribution, apparent, tap, and compact or green density, specific surface other and can be influenced by the oxide properties and reduction conditions. They represent the important criteria for further processing and are responsible for the compactability, sintering behavior, dissolution reactions during liquid-phase sintering, and carburization reaction.
Agglomeration. The different between "as supplied" and "lab milled" (deagglomerated) particle sizes is measure of the degree of agglomeration. Agglomeration is very important for the strength of the green compacts and is therefore a necessary property for powder going into ductile tungsten production.
Compressibility. This is the ratio of green density to apparent density. The ratio increasing with increasing pressure until a limit is reached. Compressibility of a powder is an important criterion for press and die design.
Much effort was expended in the past to elucidate the dependence of the compactability of tungsten powders on grain size and grain size distribution. Low grain sizes result in too low green densities due to high friction between the particles. The closer the grain size distribution, the poorer the particle packing. So it is evident that broader grain size distributions, or even blends of powders having different average grain sizes, result in better packing and higher strength of the green compacts.
Compaction and green strength is also influenced by the particle morphology. More irregular shapes, which cause interlocking, improve the strength.