High-temperature oxidation behavior of Mar-M247 and Mar-M247LC for aero-engines at 800–950 °C in air

Abstract

The isothermal oxidation behavior of Mar-M247 and Mar-M247LC was investigated in air at 800–950 °C for 500 h. The oxidation activation energies of 327.7 kJ/mol and 281.4 kJ/mol were obtained, respectively. The oxidation kinetics and oxide layer evolution indicated that the Cr3+ outward diffusion dominated the oxide film growth. Firstly, NiO replaced Cr2O3 as the outer layer above 900 °C. Next, the formation of the internal Al2O3 was closely related to the γ' phase dissolution. The size of the γ' and the γ/γ' interfacial area may be one of the possible reasons for the minor differences in the Mar-M247 and Mar-M247LC oxidation properties. And finally, it is speculated that the oxide pegs in the oxide layer enhance the adherence of the oxide film to the substrate.