On the minimum oxygen impurity content in tungsten powders

A theoretical assessment of the minimum oxygen content in tungsten powder was carried out and compared with experimental results for passivated powder. The assumption of particles being spherical in size and distributed according to a lognormal law was used. Using this method, the thickness of the oxide layer in tungsten powders recovered at temperatures of 650, 800 and 950 °С (and with average size 1.53, 2.26 and 4.54 μm) was estimated and it turns out to be much larger than the monomolecular layer: 50, 10, 5 nm, respectively.