The development of atomic imperfections within oxide films from high-temperature oxidation of heat-resistant alloys significantly limits the self-protectiveness of the surface oxide, contributing to the failure of energy generating system components such as turbines, engines, and heat exchanges. Directly probing the dynamics of such atomic defects is challenging because of the extreme thermochemical conditions of high-temperature oxidation. Using environmental transmission electron microscopy observations, here we directly capture atomic-scale dynamics of vacancies in growing Cr₂O₃ film during high-temperature oxidation of NiCr alloy in CO₂. Coordinated with theory modeling, we delineate the atomistic mechanisms associated with the effect of interstitial carbon derived from CO₂ on promoting the formation, migration and clustering of atomic vacancies to result in the enhanced alloy oxidation. The identified oxidation mechanism can find broader applicability in utilizing the atmosphere to tune the formation and evolution of atomic-scale defects, thereby affecting the mass transport properties of the growing oxide film.

耐热合金的高温氧化导致氧化膜内原子缺陷的形成，极大地限制了表面氧化物的自我保护能力，从而导致涡轮机、发动机和热交换器等发电系统部件的故障。由于高温氧化的极端热化学条件，直接探测此类原子缺陷的动力学具有挑战性。利用环境透射电子显微镜观察，我们直接捕获了_{NiCr 合金在 CO 2}中高温氧化过程中₂O₃。结合理论模型，我们描述了源自CO₂促进原子空位的形成、迁移和聚集从而增强合金氧化的作用相关的原子机制。所确定的氧化机制可以在利用大气来调节原子级缺陷的形成和演化方面找到更广泛的适用性，从而影响生长的氧化膜的质量传输特性。