Corrosion of the Fe-25Ni-15Cr superalloy under the combined effects of marine atmospheric exposure and high-temperature oxidation

Corrosion of Fe-25Ni-15Cr under the combined effects of marine atmospheric exposure and subsequent high-temperature oxidation was investigated in the present work. The results indicated that the high-temperature oxidation rate of the superalloy following field exposure was significantly accelerated due to the deposited salts and corrosion products. The oxidation kinetic process of the superalloy was clearly divided into two stages, resulting in changes in the morphology, structure and composition of the oxide film. Additionally, the sponta-neous passive state of the superalloy was changed to active dissolution by high-temperature oxidation, indicating a substantial deterioration in corrosion resistance. A damage model for superalloys under the combined effects of electrochemical corrosion and high-temperature oxidation was proposed.