ABSTRACT In this study, the oxidation behaviour of alloy 617, alloy 740, alloy HR6W and Sanicro 25 was investigated in SCW and vapour environment at 650°C for 320 h. The weight gain and the thickness of the oxide films of samples after exposure in SCW are higher than that in vapour. Inner oxidation phenomena were observed on alloy HR6W and Sanicro 25, which have higher content of Fe. The structure of the oxide films formed on alloy 617, alloy 740, alloy HR6W and Sanicro 25 after exposure in SCW at 650°C for 320 h is composed by a Fe-rich (mainly hematite) outer layer and a Cr-rich inner layer. The thickness of the outer Fe-rich layer is related with the Fe content in alloy matrix. Oxide films spallation phenomena were found on alloy HR6W after exposure in SCW.

中文翻译：

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合金 617、740、HR6W 和 Sanicro 25 在 650°C 超临界水中的高温氧化

摘要 在本研究中，研究了 617 合金、740 合金、HR6W 合金和 Sanicro 25 合金在 650°C 和蒸汽环境中 320 小时的氧化行为。样品在SCW中暴露后的增重和氧化膜厚度均高于蒸气中的增重和氧化膜厚度。在合金 HR6W 和 Sanicro 25 上观察到内部氧化现象，它们具有较高的 Fe 含量。合金617、合金740、合金HR6W和Sanicro 25在650°C的SCW中暴露320小时后形成的氧化膜结构由富铁（主要是赤铁矿）外层和富铬内层组成. 外富铁层的厚度与合金基体中的铁含量有关。合金HR6W在SCW中暴露后发现氧化膜散裂现象。