Outstanding high-temperature oxidation- and wear-resistance of WC based cermets

Abstract

The interaction between oxidation and frictional load can greatly deteriorate the performance of ceramic-metal composites. In this work, we used WC-Co cermet as a representative of ceramic-metal composites to study its wear failure behavior and protection effectiveness. It is found that a transition of wear mechanism from mechanical wear to oxidative wear occurs with increasing temperature. The addition of zirconia can significantly improve the anti-oxidation performance and load-bearing capacity of the cermet under the frictional load. This is mainly attributed to the modulation of the tribo-oxide layer constitutions and changes in surface morphology. The zirconia component facilitates the formation of a dense protective oxide layer and reduces the content of brittle oxides on the worn surface. Based on the understanding of the temperature- and oxidation-induced compositional and microstructural evolutions at the sliding contact surface and subsurface, a promising approach is proposed for developing ceramic-metal composites with high wear resistance and anti-oxidation capability.