Preparation of WC Powders by SHS Process in the Presence of Alkali Salts

Tungsten carbide powder was synthesized by SHS (self-propagating high-temperature synthesis). Except WO₃, each concentration of raw material (WO₃, Mg, NaCl, Na₂CO₃, C) was investigated. Final product was characterized by XRD and SEM. X-ray data demonstrated that the NaCl+Na₂CO₃ combined mixture has superiority in the WC formation process. Single phase and submicrometer WC powder was synthesized at the temperature below 1600℃. The role of sodium salts in combustion process was discussed, and chemical mechanism of WC formation was proposed. WC powder prepared by salt-assisted combustion synthesis has a size 0.2~3 μm and low agglomeration degree.