Manufacturing of Nano-sized WC Powder by Direct Carburization of WO3

Nano-sized WC powder that is expected as the raw material for nano-sized WC-Co hardmetals with high hardness and strength was developed. The reaction path and morphological change in the reaction process of WO3 with carbon powder (direct carburization) were firstly investigated by thermogravimetric analysis. The proper reaction condition examined by the thermogravimetric analysis was developed to trial production by direct carburization facilities.The direct carburization reaction from WO3 to WC occurred through the generation of several intermediate products in the order of WO3 → WO2.72 → WO2 → W → W2C → WC. The nano-sized particles were generated at the stage from WO2.72 to WO2. We succeeded in the development of nano-sized WC powder less than 100 nm by controlling the reaction conditions for each intermediate products.