Ni 기지 초내열합금의 고온산화 저항성에 미치는 Ti의 영향

The effects of Ti on the high temperature oxidation of Ni-based superalloys were investigated by cyclic oxidation at 850 °C and 1000 °C. The oxide scale formed at 850 °C consists of Cr2O3, Al2O3, and NiCr2O4 layers, while a continuous Al2O3 layer was formed at 1000 °C. The oxidation rate of the alloy with higher Ti content was higher than the alloy with less Ti content at 850 °C, possibly due to the increase in the metal vacancy concentration in the Cr2O3 layer involved by incorporation of Ti4+. However, Ti improved the oxidation resistance of the superalloy at 1000 °C by reducing oxygen vacancy concentration in Al2O3 layer.