High temperature oxidation behavior of Ni-based superalloy Nimonic95 and the effect of pre-oxidation treatment

The high-temperature oxidation behaviors of Nimonic95 alloy at 800 °C, 900 °C and 1000 °C were studied. The diffusion process of alloying elements in different stages of oxidation was studied and analyzed, and the pre-oxidation process was established. The results showed that multilayer oxide films formed in the air at 800 °C, 900 °C and 1000 °C, the outer layer was mainly Cr2O3 with a small amount of Al2O3, TiO2 and composite oxides such as CrTi spinel. The inner layer was mainly Al2O3. Nimonic95 alloy has excellent oxidation resistance at 800 °C and 900 °C, but poor oxidation resistance at 1000 °C and the oxide film peeled off in a short time. The oxidation resistance of Nimonic95 alloy at 1000 °C can be improved significantly by pre-oxidation at 800 °C for 140 h. •The oxidation behavior of Nimonic95 alloy at 800 °C, 900 °C and 1000 °C was studied.•The diffusion mechanism of the alloy elements during different stages of oxidation was revealed.•The mechanism of improving the oxidation resistance of Nimonic95 alloy at 1000 °C by pre-oxidation process was revealed.