Liquid phase sintering and oxidation resistance of WC–Ni–Co–Cr cemented carbides

Fully dense WC–Ni–Co–Cr alloys have been consolidated via sinter HIP processing. Dilatometric tests show that shrinkage undergoes several accelerations and decelerations during heating, a phenomenon likely associated to the heterogeneous distribution of Cr in the binder phase. WC grain growth follows trends similar to those described for WC–Co hardmetals, increasing with the C activity and the amount of liquid phase of the cermets. Finally, the oxidation resistance of WC–Ni–Co–Cr cemented carbides is observed to improve as the metal content increases and the C content decreases. In both cases, the oxide layers present a higher proportion of (Co, Ni)WO4 tungstates. The oxide scales formed on compositions with low metal content contain a higher amount of WO3 oxide.