Preparation of uniform tungsten powder by wet hydrogen reduction and its process regulation

Tungsten powders with uniform particles were prepared by wet hydrogen and dynamic reduction. The effects of the dew point of hydrogen and reduction temperature on the size of tungsten particles were investigated. The results showed that the increase in reduction temperature increased the nucleation and growth rate of tungsten particles. The particle size distribution interval increased from 1-4 mu m to 1-6 mu m. The high hydrogen dew point led to the enhancement of the chemical vapor transport(CVT) process, which accelerated the growth rate of fine particles and ultimately improved the tungsten powder uniformity. However, wet hydrogen increases the equilibrium constant of the reaction, resulting in a lower reduction rate.