| Abstract Scope |
The formation of atomic imperfections within oxide scales during high-temperature oxidation of heat-resistant alloys severely compromises the self-protective nature of the surface oxide layer. Directly investigating the dynamics of these atomic defects is challenging due to the extreme thermochemical conditions involved. CO2, a byproduct of petrochemical fuel combustion, is highly corrosive and leads to significant oxidation of critical components in power systems. Through environmental transmission electron microscopy, we observe the atomic-scale dynamics of vacancies in growing Cr2O3 films during high-temperature oxidation of NiCr alloy in CO2. Coordinated with atomistic modeling, we delineate how interstitial carbon derived from CO2 promotes the formation, migration, and clustering of atomic vacancies, thereby accelerating alloy oxidation. |