WC-Co 초경합금의 산화거동

Abstract

The oxidation behavior of 91WC-9Co hardmetal in weight percentage has been studied in the present work as a part of the development of recycling process. The morphological and compositional changes of the WC-Co hardmetal with oxidation time at 900℃ were analyzed by using surface observation and X-ray diffraction, respectively. As the oxidation time increased, the WC-Co hardmetal was continuously expanded to form porous oxide mixtures of CoWO4 and WO3. The morphology of porous oxide mixture was basically dependent on initial shape of the WC-Co hardmetal. From thermo-gravimetric (TG) analysis, it was found that the oxidation rate was increased with increasing oxidation temperature and oxygen content in the flowing atmospheric gas. The fraction of oxidation versus time curves showed S-curve relationship at a given oxidation temperature. These oxidation behaviors of the WC-Co hardmetal were discussed in terms of previously proposed kinetic models.