The oxidation behavior of a new Ni-Cr-Mo-Si alloy has been evaluated from 1000°C to 1200°C in air plus 5% water vapor and in oxygen at 1200°C, under cyclic conditions. For comparison, two commercial and two experimental Ni-Cr-Si-Nb alloys and alloys HX, 600 and MA758 were included. The experimental results show that the Ni-Cr-Mo-Si material has excellent resistance to oxidation attack, provided by both a continuous chromium oxide scale, a discontinuous silicon oxide sub-scale, and rare-earth additions. Sample characterization methods include light and SEM microscopy and EPMA.
Keywords: Nickel-base alloys, oxidation, silicon oxide, chromium oxide, rare earth addition