目的 获得奥氏体不锈钢HR3C在605 ℃-26 MPa和640 ℃-26 MPa超临界水环境中的抗氧化性能，为燃煤电站锅炉管材料损伤机理研究提供数据支撑。方法 在超临界水氧化实验平台开展了奥氏体钢HR3C在605 ℃-26 MPa和640 ℃-26 MPa超临界水中氧化2 000 h实验。为探究氧化膜生长机理，进一步开展了奥氏体钢HR3C在含H2¹⁸O超临界水中的氧化实验。利用电子天平、场发射电子显微镜、能谱仪、X射线衍射仪、X射线光电子能谱仪以及二次离子质谱仪对试样氧化动力学、氧化膜微观形貌、元素组成、物相成分以及¹⁸O分布进行了检测。结果 奥氏体钢HR3C氧化动力学在605 ℃下遵循抛物线规律，640 ℃下偏离抛物线规律。HR3C表面形成的氧化膜主要为Fe3O4/尖晶石、Fe2O3、Cr2O3以及MnO。外层主要为富铁氧化物，内层为富铬氧化物。¹⁸O主要分布于氧化膜外层。640 ℃下氧化2 000 h后氧化膜发生明显剥落。结论 温度的升高增加了HR3C的氧化速率和剥落倾向，氧化初期金属离子的扩散导致氧化膜生长，长时氧化过程金属离子和氧离子扩散导致双层氧化膜的形成。较高的富铬氧化物含量，是HR3C具有较高抗氧化性能的主要原因。

High main steam parameters can effectively improve the generation efficiency of coal-fired power stations. However, once the temperature and pressure of water vapor exceed the critical point, it shows strong oxidation. Austenitic steel HR3C is widely used in superheaters and reheaters of power stations. It is very important to evaluate the high temperature oxidation property of HR3C in supercritical water. Oxidation experiments of austenitic stainless steel HR3C in supercritical water environments at 605, 640 ℃ and 26 MPa are performed to investigate the oxidation resistance of HR3C steel. The supercritical water oxidation experimental system can withstand the maximum temperature and pressure of 700 ℃ and 27 MPa. The samples are suspended in the constant temperature section of the reactor. The experiment adopts the method of interrupt experiment at interrupt time points of 300, 500, 800, 1 500 and 2 000 h respectively. The sample is weighed before and after the experiment. It provides a data support for the research on the damage mechanism of boiler tube material in coal-fired power stations. In order to explore the mechanism of oxide film growth, the oxidation experiment of austenitic steel HR3C in supercritical water containing H218O is further carried out in a static autoclave. For the oxygen isotope labeling experiment, it is carried out in supercritical water (H216O) for 100 h in a static reactor, followed by oxygen-containing isotope supercritical water (H216O+H218O). Based on the distribution of oxygen isotopes, it can reveal the diffusion path of oxygen and the growth process of the oxide film. The oxidation kinetics, surface oxide morphology and structure, elemental composition and phase composition are identified by electronic balance, scanning electron microscope (SEM) equipped with energy dispersive X-ray spectrometer, X-ray diffraction, X-ray photoelectron spectrometer and secondary ion mass spectrometer. The oxidation kinetics of austenitic steel HR3C follows near the parabolic law at 605 ℃ and deviates from the parabolic law at 640 ℃. It indicates that the oxidation process is controlled by ion diffusion. The oxide formed on HR3C is mainly Fe3O4/spinel, Fe2O3, Cr2O3 and MnO. The oxide films consist of a Fe-rich outer layer and a Cr-rich inner layer. The oxygen isotope 18O located at the outer oxide film is detected. Scale spallation from HR3C is observed after 2 000 hours at 640 ℃. The oxidation rate and spalling tendency of HR3C increase with the increase of temperature, the outward diffusion of metal ions in the initial oxidation stage leads to the growth of the oxide film, and the diffusion of metal ions and oxygen ions lead to the formation of the double-layer oxide film in the long-term oxidation process. The high chromium-rich oxide content formed on the surface of HR3C due to the high metal chromium content. It can effectively prevent the outward diffusion of metal cations and the inward diffusion of oxygen. Thus, HR3C shows high oxidation resistance. The approximate service environment and the use of the isotope tracer method can effectively evaluate the oxidation resistance of HR3C stainless steel. The results of this paper can provide a data support for the oxidation resistance evaluation of austenitic steel HR3C.