Size control of tungsten powder synthesized by self-propagating high temperature synthesis process

Abstract

Tungsten powder was prepared by self-propagating high temperature synthesis (SHS) from a mixture of WO 3 and Mg. The MgO in the product was leached with an HCl solution. The complete reduction of WO 3 required a 33% excess of magnesium over the stoichiometric molar ratio Mg/WO 3 of 3. The tungsten product had a purity of 99.98%, which was higher than that of the reactants. The high purity resulted because the impurities in the reactants were volatilized during the highly exothermic reaction and dissolved during leaching of the product. Size distribution and the shape of the tungsten particles produced was affected by compaction pressure on the green pellet.