Powder Technology, Vol.228, 187-192, 2012
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 mu m were obtained from polyhedral W particles with an average particle size of 7.5 mu m. 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. (C) 2012 Elsevier B.V. All rights reserved.
Keywords:Tungsten particles;Localized preferential oxidation;Shape modification;Spheroidizing process