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采用热重分析(TGA)方法研究了离子注镧对Co-40Cr合金在1000℃空气中的恒温氧化和循环氧化行为的影响.用扫描电镜(SEM)和透射电镜(TEM)对表面氧化膜的微观形貌和结构进行了研究.用二次离子质谱(SIMS)对合金表面元素铬结合能的变化情况以及氧化膜中元素镧的深度分布进行了测试,并用激光拉曼谱(Raman)对掺杂镧引起的氧化膜内应力改变进行了测量研究.结果表明,离子注镧后Co-40Cr合金在1000℃空气中的恒温氧化速率显著降低,表面Cr2O3氧化膜的抗开裂与抗剥落性能明显增强.原因主要是镧细化了Cr2O3氧化膜的晶粒尺寸、降低了氧化膜内应力水平并增加了氧化膜的高温塑性.稀土镧主要以La2O3和LaCrO3的形式存在于Cr2O3氧化膜的外侧,通过阻碍膜内阳离子扩散影响膜的生长规律,进而改善氧化膜的黏附性能.
The effect of ion-injection lanthanum on the isothermal oxidation and cyclic oxidation of Co-40Cr alloy in air at 1000 ℃ was investigated by thermogravimetric analysis (TGA). The surface oxide film was characterized by scanning electron microscopy (SEM) and transmission electron microscopy The microstructure and morphology of the alloy were investigated by SIMS. The changes of the chromium binding energy of the alloy surface and the depth distribution of lanthanum in the oxide film were studied. Lanthanum-doped oxide film.The results showed that the oxidation rate of Co-40Cr alloy at 1000 ℃ in the atmosphere after ion-injection of La was significantly decreased, and the anti-cracking and anti-spalling properties of Cr2O3 oxide film on the surface were significantly enhanced . The main reason is that the grain size of the Cr2O3 oxide film is refined by lanthanum and the stress level in the oxide film is reduced and the high temperature plasticity of the oxide film is increased.Repadite lanthanum is mainly present on the outside of the Cr2O3 oxide film in the form of La2O3 and LaCrO3 Hindered the membrane cation diffusion affect the growth of the film, thereby improving the adhesion of oxide film.