Synthesis of nanostructured tungsten carbide via metal-organic chemical vapor deposition and carburization process

Abstract

Nanostructured tungsten carbide particles were successfully synthesized by metal-organic chemical vapor deposition in a spouted bed followed by carburization in CH4/H2 atmosphere in the temperature range 700–900°C. The carburization process was a little bit complex, which involved the coating of carbon on the outer surface of the decomposed W(CO)6 precursor particles and then followed by carbon diffusion into the particles, leading to the formation of nanostructured WC via an intermediate metastable phase W2C. The carbon deficient phase W2C was formed initially at lower carburization temperature and then transformed to stable WC phase by increasing the temperature and holding time.