Preparation of tungsten carbides by reducing and carbonizing WO2 with CO

Tungsten carbides, which can be widely used as cutting and drilling tools, chemical catalysts and aerospace coatings, have attracted widespread attentions. The present work reported a simple method to prepare tungsten carbides by using WO2 as the raw materials and CO as the reduction and carbonization agent. It was found that at lower and moderate temperatures, all the final product was WC, while at higher temperatures, the final products were W2C or W. The reduction and carbonization mechanism was also studied theoretically and experimentally. WO2 was reduced and carburized to WC in one step at lower temperatures; WO2 was first reduced and carburized to W2C and then to WC at moderate temperatures; while at higher temperatures, WO2 was first reduced to metallic W and then carbonized to WC or W2C, but with the temperature increasing, the carbonization became difficult and required much higher CO content.