To improve the oxidation properties of ferritic heat-resistant steels, an Al-bearing 9Cr-5Si-3Al ferritic heat-resistant steel was designed. We then conducted cyclic oxidation tests to investigate the high-temperature oxidation behavior of 9Cr-5Si and 9Cr-5Si-3Al ferritic heat-resistant steels at 900 and 1000°C. The characteristics of the oxide layer were analyzed by X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy. The results show that the oxidation kinetics curves of the two tested steels follow the parabolic law, with the parabolic rate constant k_p of 9Cr-5Si-3Al steel being much lower than that of 9Cr-5Si steel at both 900 and 1000°C. The oxide film on the surface of the 9Cr-5Si alloy exhibits Cr₂MnO₄ and Cr₂O₃ phases in the outer layer after oxidation at 900 and 1000°C. However, at oxidation temperatures of 900 and 1000°C, the oxide film of the 9Cr-5Si-3Al alloy consists only of Al₂O₃ and its oxide layer is thinner than that of the 9Cr-5Si alloy. These results indicate that the addition of Al to the 9Cr-5Si steel can improve its high-temperature oxidation resistance, which can be attributed to the formation of a continuous and compact Al₂O₃ film on the surface of the steel.

为了改善铁素体耐热钢的氧化性能，设计了一种含铝9Cr-5Si-3Al铁素体耐热钢。然后，我们进行了循环氧化试验，以研究9Cr-5Si和9Cr-5Si-3Al铁素体耐热钢在900和1000°C下的高温氧化行为。通过X射线衍射，扫描电子显微镜和能量色散光谱分析了氧化物层的特性。结果表明，两种测试钢的氧化动力学曲线均符合抛物线规律，在900℃和1000℃下，9Cr-5Si-3Al钢的抛物线速率常数k _p均远低于9Cr-5Si钢。9Cr-5Si合金表面的氧化膜显示Cr ₂ MnO ₄在900和1000℃下氧化后，外层中的Cr ₂ O ₃相和Cr ₂ O ₃相。然而，在900和1000℃的氧化温度下，9Cr-5Si-3Al合金的氧化膜仅由Al ₂ O _3组成，并且其氧化层比9Cr-5Si合金的氧化膜薄。这些结果表明，向9Cr-5Si钢中添加Al可以改善其高温抗氧化性，这可以归因于在钢表面上形成连续且致密的Al ₂ O ₃膜。