目的 考察NiCr/Cr3C2?BaF2/CaF2涂层在高温氧化环境下成分与结构变化，着重研究氧化对涂层机械和摩擦学性能影响。方法 采用超音速火焰喷涂(HVOF)制备出NiCr/Cr3C2?BaF2/CaF2涂层，对涂层进行700、800、850 ℃氧化处理，借助扫描电镜、X射线衍射仪、显微硬度计、力学性能试验机和高温摩擦磨损试验机等设备，比较了喷涂态涂层与氧化处理后涂层的微观结构、物相成分及机械和摩擦学性能。结果 涂层在700 ℃以上氧化环境中，会发生氧化诱导下以氟化物润滑相表面迁移和表面Cr选择性氧化等行为构成的铬酸盐反应。该反应在850 ℃时会使涂层性能形成“嬗变”，在该温度下氧化处理后涂层的结合强度由喷涂态的75 MPa急剧下降至20 MPa，涂层近表显微硬度由735HV下降至190HV;此外，涂层在300 ℃时体积磨损率由喷涂态的2.19×10⁵ mm³/N.m剧增至16.3×10⁵ mm³/N.m。结论 高温氧化诱导下的铬酸盐反应，不仅会破坏涂层中粘结相、耐磨相和润滑相的分布均匀性，而且会使涂层孔洞、裂纹等缺陷显著增加，由此导致涂层的机械和摩擦磨损性能大幅下降。对于工作时摩擦闪温超过800 ℃的含氟化物刷式封严涂层而言，涂层在经历闪点后所发生的性能“嬗变”是其短期失效的重要因素。提高涂层的抗氧化性能、降低高温下铬酸盐反应烈度将会是改善涂层失效的有效方法。

The work investigates the compositional and structural changes of NiCr/Cr3C2- BaF2/CaF2 coatings under high temperature oxidation, with emphasis on the effect of oxidation on the mechanical and tribological properties of the coatings which were prepared by HVOF and oxidized at 700，800 and 850 ℃. With the aid of scanning electron microscopy, X-ray diffractometer, microhardness tester, tensile tester and high temperature tribometer, the microstructure, composition and mechanical and tribological properties of the as-sprayed coating were compared with those of the oxidized coatings. One specific, frictional wear test was carried out on a high temperature ball-on-disk tribotester (UMT-Tribolab). The results of previous studies have shown that the coating wears most severely when tested near 300 ℃. This temperature point was chosen to investigate the frictional wear performance of the coating before and after the oxidation treatment, based on the most demanding frictional wear environment.