Plasma synthesis of nanosized W-Co composite powder followed by carburization with a methane-hydrogen mixture

Abstract

Nanosized tungsten carbide and cobalt composite powder was synthesized by a two-step reaction via a thermal plasma process. Ammonium paratungstate (APT) and cobalt oxide were used as the precursors. The injected precursors were vaporized in the plasma flame and the subsequent reduction of the vaporized precursors produced uniformly mixed nanosized tungsten and cobalt composite powder. The subsequent carburization of this powder by CH4-H-2 mixture resulted in the formation of nanosized WC-Co composite powder with a particle size < 110 nm. This new method represents an alternative route that avoids the post-treatment required for the WC1-x produced when methane was used for direct carburization in the powder production step.