XPS study of WC formation process

Abstract The surface composition and chemical bonding state of WO 3 carburized in CO at 700°C have been investigated with X-ray photoelectron spectroscopy, in order to clarify the mechanism of WC formation. The experimental results show that the carburization process is based on a direct reaction of WO x ( x ≦3) with free carbon which accumulates on the WO x surface by the disproportionation of CO. A model for the WC formation process is also presented.