候选材料在650℃超临界水中的腐蚀行为研究

摘要

研究了3种候选材料（347、H R3C和In-718）在650℃、25 M Pa去离子水中的均匀腐蚀行为，使用场发射扫描电镜（FEG-SEM ）和能谱（EDS）观察了不同腐蚀时间的表面氧化膜形貌与合金元素分布，使用掠入射X射线衍射（G IX RD ）分析了氧化膜相结构。结果表明，3种材料腐蚀失重均符合抛物线规律，347的失重为 HR3C和In-718的40倍以上；3种材料氧化膜均以 Ni（Cr ，Fe）2 O4为主，In-718点蚀严重，347氧化膜明显脱落，H R3C氧化膜较均匀致密；高温超临界水中，提高合金的C r含量有助于增强均匀腐蚀性能，添加Nb有损合金的点蚀抗力。%The general corrosion behavior of three candidate materials (347 ,HR3C and In-718 ) was investigated in 650 ℃ /25 MPa deionized water . Morphology and composition of the surface oxide film with different exposure time were observed through FEG-SEM and EDS .The phase constitute was analyzed by GIXRD .For all the test materials ,the weight loss follows typical parabolic law and the weight loss of 347 shows more than 40 times higher than that of HR3C and In-718 .The oxide film of three alloys mainly consists of Ni(Cr, Fe)2O4 .In-718 shows severe pitting and the oxide film of 347 appears significant spalling ,while HR3C has compact oxide film .In the high temperature supercritical water ,the high Cr content may enhance the general corrosion property of the alloys ,while addition of Nb may be detrimental to the pitting resistance of alloys .