Abstract: In this paper, candidate materials of supercritical and ultra-supercritical utility boiler water wall T23 and T24 were chosen as the experimental samples, and exposed to an oxidizing atmosphere, reducing atmosphere and oxidizing/reducing alternating atmosphere respectively. The corrosion temperature was 450℃. Besides, the effect of oxygen content and temperature on the corrosion in reducing atmosphere and alternating atmosphere was studied respectively. The scanning electron microscope (SEM) and Energy Dispersive Spectrometer (EDS) were used to analyze the corroded samples. The results show that the corrosion kinetics of T23 and T24 can be described by the double logarithmic equation and parabolic equation respectively. To describe the corrosion of materials accurately it is not sufficient to just analyze the macro-weight gain and the macro-thickness of the corroded layer, the ESD must be applied at the same time to analyze the depth of the migration of the corrosive elements O and S in the corrosion. It is revealed that corrosion becomes more severe when there is H2S in the corrosive gas. S is more active than O, and Cr can disappoint the migration of oxygen instead of S. The combination corrosion of S and O and pure [S] has a stronger corrodibility than pure H2S. T24 suffers the most severe corrosion in the oxygen content of 0.8%. Corrosion is aggravated when the corrosion temperature is above 450℃ in the alternating atmosphere. T23 has a stronger corrosion resistance than T24 and W contributes a lot to the corrosion resistance of T23.

摘要： 本文以电站锅炉水冷壁候选材料T23、T24为研究对象，对两种材料在450℃，氧化性气氛、还原性气氛以及氧化——还原交替气氛三种工况下进行高温腐蚀实验研究，且研究了氧含量在还原性气氛中的作用以及温度对交替气氛下腐蚀量的影响，通过电镜和能谱对结果进行分析。研究发现：T23的腐蚀规律符合双对数方程，而T24的腐蚀规律符合抛物线方程；宏观腐蚀增重、腐蚀层厚度及迁移深度三者结合起来才能正确表征材料的腐蚀程度；有H2S存在时高温腐蚀明显加重；S的迁移能力比O强，Cr能够抑制O的迁移，却不能够有效抑制S的迁移；O与S相互促进的腐蚀模式比单纯H2S腐蚀更严重；还原气氛中O含量在0.8%时T24的腐蚀最严重，[S]的腐蚀能力强于H2S的腐蚀能力；交替气氛下T24在450℃以上时腐蚀明显增强；T23的抗腐蚀能力明显强于T24；W在增强T23抗腐蚀能力方面起到了重要作用。

关键词: 不锈钢, 高温腐蚀, 元素迁移, 增重