Effect of Cr and W addition on the oxidation behavior of Ni–8%Al alloy at 1000 °C

Abstract

The effect of (6 wt%) Cr and (6 wt%) W on the oxidation behavior of Ni–8%Al alloy at 1000 °C in air was investigated. The oxidation-affected zones of Ni–8%Al–6%Cr/W alloys consist of outer oxidation zone (NiO layer) and mixed internal oxidation zone. The addition of Cr promotes the formation of the intermediate Ni(Al, Cr)2O4 layer and internal Al2O3 in internal oxidation zone, which provides a blocking effect and reduces the oxidation rate of Ni–8%Al–6%Cr alloy. However, the addition of W element facilitates the development of non-protective NiO and NiWO4 oxides, which accelerates the oxidation of alloy. As a result, Ni–8%Al–6%W alloy shows poor oxidation performance.