The selective oxidation behaviour of WC–Co cemented carbides during the early oxidation stage

The oxidation experimental of WC–Co cemented carbides was carried out at 500 °C in air. Selective oxidation phenomenon of Co phase in WC–Co cemented carbides was observed and proved by EPMA and AFM. At first, the O content in Co phase increases quickly, and then tends to be stable after oxidation of 20 min. In sharp contrast, no change of O content in WC phase was observed. Moreover, it was found that the oxide scales thickness of Co phase increased parabolically with oxidation time. And thermodynamic and kinetic analysis of oxidation was done.