9Cr低活化马氏体钢在超临界水中的腐蚀行为

摘要

利用扫描电子显微镜(SEM)、电子能谱(EDS)以及X射线衍射(XRD)技术研究了9Cr低活化马氏体钢在650℃/25MPa超临界水中的腐蚀行为.结果表明,9Cr低活化马氏体钢腐蚀产物的晶粒随腐蚀时间的延长而长大,晶粒尺寸从200h的5.7μm长大到1000h的10.1μm.表面形成的氧化膜为双层结构,外层为Fe3O4,内层由Fe3O4和FeCr2O4共同组成.由氧化增重结果获得了9Cr低活化马氏体钢在超临界水中腐蚀的氧化动力学表达式,同时其腐蚀机理表现为吸氧腐蚀.%Corrosion behaviour of 9Cr low activation martensitic steel in supercritical water(SCW) at 650℃ and 25MPa was investigated by scanning electron microscopy(SEM), energy dispersive spectrometer(EDS) and X-ray diffraction(XRD) analysis. The results indicate that the grain size of corrosion product of 9Cr low activation martensitic increases with the exposure time expanding in SCW, and a double layer oxide structure develops on samples. The outer layer is magnetite(Fe3 O4 ) and the inner layer consists of magnetite and spinel phase(FeCr2 O4 ). The weight gain show that the oxidation rates of 9Cr low activation martensitic steel follow the power law expression and only oxidation instead of metal dissolution occurred under SCW condition.