核级不锈钢和铁素体-马氏体耐热钢在400℃/25 MPa超临界水中的腐蚀行为

CORROSION BEHAVIORS OF NUCLEAR-GRADE STAINLESS STEEL AND FERRITIC-MARTENSITIC STEEL IN SUPERCRITICAL WATER

利用腐蚀增重法,XRD,Raman光谱和SEM研究了核级304不锈钢和铁素体-马氏体耐热钢P92在400℃/25 MPa超临界水中的腐蚀行为.结果表明,2种材料都以均匀腐蚀为主,增重曲线遵循幂指数规律.304不锈钢的腐蚀增重比P92钢低近一个数量级,其氧化膜很薄,局部存在少量的疖状腐蚀.氧化膜主要由Cr_2O_3,α-Fe_2O_3,Fe_3O_4和尖晶石结构氧化物组成.P92钢的氧化膜主要由α-Fe_2O_3,Fe_3O_4和尖晶石结构氧化物组成,表层主要含α-Fe_2O_3.延长腐蚀时间.P92钢表面氧化膜在超临界水中溶解,导致氧化膜形貌由致密的多面体颗粒演化为相互连通的多孔网络结构.

The corrosion behaviors of nuclear-grade 304 stainless steel （304SS） and ferritic martensitic steel P92 exposed to 400℃/25 MPa supercritical water were investigated. The exposed specimens were characterized by weight gain measurement, XRD, Raman spectroscopy and SEM. It is found that both materials show general corrosion and exponential kinetics in mass gain, and the mass gain of 304SS is approximately an order of magnitude less than that of steel P92. The oxide film on 304SS is rather thin and composed of Cr2O3, α-Fe2O3, Fe3O4 and spinel, some nodules were observed on the surface. While the oxide film on steel P92 consists of α-Fe2O3, Fe3O4 and spinel, more α-Fe2O3 exist in the outer surface of the oxide film. The surface morphology of oxide film on steel P92 changes from dense particles to porous network structure with increasing exposure time, which may be relative to the dissolution of oxide.