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研究了不同铝含量的Fe-25Cr-20Ni在900℃、1 000℃和1 100℃的高温氧化行为。其中,Fe-25Cr-20Ni-4.72Al在900℃、1 000℃和1 100℃时的平均氧化速度比Fe-25Cr-20Ni分别降低47.14%、58.14%和17.49%。X射线衍射分析结果表明,氧化膜主要为Fe、Cr的氧化物和尖晶石(NiCr2O4、FeCr2O4),其中在Fe-25Cr-20Ni-4.72Al合金中检测到了Al2O3。对氧化后试样截面进行扫描电镜观察和能谱分析,结果表明,不含铝以及铝的质量分数为1.68%和7.10%的试样氧化后氧化膜分为两层:即厚度较为均匀,存在较多的破碎、剥落的外层和外层与基体之间的较为致密,但存在空穴的内层;铝的质量分数为4.72%的试样氧化膜较为致密,基本无剥落,分层现象不明显,生成的Al2O3存在于氧化膜的最外层,有效防止了材料的进一步氧化。
The oxidation behavior of Fe-25Cr-20Ni with different aluminum contents at 900 ℃, 1 000 ℃ and 1 100 ℃ was studied. Among them, the average oxidation rate of Fe-25Cr-20Ni-4.72Al at 900 ℃, 1 000 ℃ and 1 100 ℃ decreased by 47.14%, 58.14% and 17.49% respectively than Fe-25Cr-20Ni. X-ray diffraction analysis showed that the oxide films were mainly Fe, Cr oxides and spinel (NiCr2O4, FeCr2O4), in which Al2O3 was detected in Fe-25Cr-20Ni-4.72Al alloy. Scanning electron microscope (SEM) observation and energy spectrum analysis of the cross-section of the samples after oxidation show that the oxide film without oxidation of aluminum and aluminum with the mass fraction of 1.68% and 7.10% is divided into two layers: that is, the thickness is relatively uniform and exists More broken, exfoliated outer layer and the outer layer and the matrix between the more dense, but there is a hole in the inner layer; aluminum mass fraction of 4.72% of the sample oxide film is more dense, almost no spalling, stratification Obviously, the generated Al2O3 is present in the outermost layer of the oxide film, effectively preventing the further oxidation of the material.