Sphericizing tungsten particles by means of localized preferential oxidation and alkaline washing

A novel technique has been developed to sphericize polyhedral tungsten (W) particles by means of localized preferential oxidation and alkaline washing. Near spherical W particles with an average particle size of 6.10 μm were obtained from polyhedral W particles with an average particle size of 7.5 μm. The study showed oxidation temperature and time affected the spheroidization of W powder particles and the mass loss. The alkaline washing process showed critical effectiveness on the removal of oxide layer from the particle. A model based on the oxidizing kinetics of spherical W particles was proposed for optimizing oxidation process of polyhedral W particles, which provides a good interpretation for the process at the test temperatures.