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. (C) 2010 Elsevier Ltd. All rights reserved.