超超临界电站国产奥氏体钢C-HRA-5在超临界水中的氧化特性

Oxidation Behavior in Supercritical Water of Domestic Austenitic Steel C-HRA-5 for Uultra-supercritical Power Stations

研究了奥氏体不锈钢C-HRA-5,在650℃/25 MPa和700℃/25 MPa超临界水环境中的氧化性能,借助SEM、EDS、XRD及Raman光谱等手段分析了C-HRA-5钢的氧化膜形貌、分布及成分,并探讨了奥氏体钢在超临界水中的氧化机理。结果表明,C-HRA-5钢在超临界水中生成了富Fe/富Cr双层结构氧化膜,氧化膜与基体间存在较薄的内氧化过渡区。随着温度的升高,C-HRA-5钢的氧化增重速率逐渐增大,且700℃的氧化增重速率大于650℃的氧化增重速率。氧化动力学规律在650与700℃时分别呈现近似抛物线和立方规律。

The oxidation behavior of austenitic stainless steel C-HRA-5 was studied in 650℃/25 MPa and 700℃/25 MPa supercritical water.Then its oxidation products were characterized by means of SEM,EDS,XRD and Raman spectroscopy in terms of the morphology and composition.Results show that a double layered oxide scale rich in Fe and Cr was formed on C-HRA-5 steel after oxidation test in the supercritical water,while a thin internal oxidation transition zone was also formed between the outer oxide scale and the matrix.As the temperature increases,the oxidation weight gain rate of C-HRA-5 increases gradually,and the oxidation weight gain rate at 700℃is greater than the that at 650℃.The oxidation kinetics follows approximately parabolic and cubic law at 650 and 700℃,respectively.