Influence of Processing Parameters on the Microstructure and Oxidation Behavior of Hot Pressed Ni-20Cr + WC Metal Matrix Composites

Ni20Cr+WC composites with a gradient in the volume fraction of hard WC particles are ideal materials for applications where high temperature oxidation and erosion resistance are desired properties. The WC particles impart erosion resistant and the Cr content of the alloy, oxidation resistance. This paper presents the influence of WC particle content and consequently the extent of densification, on the oxidation behavior of hot pressed Ni20Cr+WC composites. Oxidation measurements in the range 700-1000°C revealed overall parabolic behavior. The increase in oxidation rate with WC content has been attributed to formation of islands of WO 3 globules protruding through the Cr 2 O 3 .