新型含铝奥氏体不锈钢在超临界水环境下的腐蚀行为

Corrosion Behavior of a Novel Alumina-forming-austenitic Stainless Steel Exposed to Supercritical Water

为了丰富含铝奥氏体不锈钢(AFAs)在超临界水环境下的腐蚀行为研究数据,支持超临界水冷堆(SCWR)包壳材料评估工作,本研究对自主设计的AFAs进行600℃/25 MPa的超临界水腐蚀实验,结合微观分析表征手段分析其腐蚀行为。结果表明,本研究所用AFAs在腐蚀1000 h后的增重达34 mg/dm^(2),约为相同条件下的310S钢的腐蚀增重的一半。AFAs表面形成了双层氧化物,外层主要为Fe_(2)O_(3)和富Ni尖晶石,内层主要为Cr_(2)O_(3)。氧化铝以离散的颗粒形式存在于内层,阻碍扩散过程的同时可以作为Cr_(2)O_(3)的形核位点,促进Cr_(2)O_(3)的形成。因此,本研究所用AFAs在该实验条件下表现出优异的耐腐蚀性能。

In order to enrich the research data on the corrosion behavior of alumina-formingaustenitic stainless steel(AFAs) in the supercritical water environment and provide support for SCWR cladding material evaluation,this study conducted the supercritical water corrosion test at600℃/25 MPa for the independently designed AFAs,and analyzed its corrosion behavior by combining the microscopic analysis and characterization methods.The results show that the corrosion weight gain of AFAs exposed for 1000 h is 34 mg/dm~2,about half of that of 310S steel under the same conditions.There is a double-layer oxide forming on surface of AFAs.The outer layer mainly consists of Fe_2O_(3) and Ni-rich spinel,and the inner layer is mainly composed of Cr_2O_3.Alumina exists in the layer as discrete particles,hindering the diffusion process and promoting the formation of Cr_2O_3.Therefore,AFAs in this study showed excellent corrosion resistance.