Combustion synthesis of WC powder in the presence of alkali salts

This paper deals with the formation of tungsten carbide sub-micrometer powders from WO3 + Mg + C + sodium salts (NaCl, Na2CO3) system by combustion synthesis technique. The powders were characterized by XRD and FESEM. X-ray data demonstrate the superiority of the NaCl + Na2CO3 combined mixture in the WC formation process. Single phase, sub-micrometer WC powders were synthesized at temperatures as low as 1600 °C. The roles of sodium salts in combustion process were discussed and chemical mechanism of WC formation was proposed. WC powder produced by salt-assisted combustion synthesis technique has a size 0.2–3 μm, crystalline shape and low agglomeration degree.