Monel K-500合金在人造海水中的点蚀特征的研究  

Pitting Corrosion Characteristics of Monel K-500 Alloy in the Artificial Seawater

作　　者：秦明花 郑文杰[1] 王娟[2] 朱玉亮[1] QIN Ming-hua;ZHENG Wen-jie;WANG Juan;ZHU Yu-liang(Institute for Special Steels,Central Iron and Steel Research Institute,Beijing 100081,China;Wuhan Second Ship Design and Research Institute,Wuhan 430064,China)

机构地区：[1]钢铁研究总院特殊钢研究所,北京100081 [2]武汉第二船舶设计研究所,武汉430064

出　　处：《装备环境工程》2022年第6期106-112,共7页Equipment Environmental Engineering

摘　　要：目的研究Monel K-500合金在海水环境中的点蚀特征。方法采用扫描振动电极技术(SVET)中的恒电流模式,研究Monel K-500合金点蚀的萌生及生长过程,通过扫描电镜(SEM)表征点蚀区域的形貌特征。结果SVET结果显示,负电位会从点蚀中心位置向其边界区域转移,且更负的大阳极区能够吞并电位高的小阳极区。SEM结果显示,点蚀附近会发生TiC表面腐蚀产物的堆积、TiC周围基体的溶解及TiC的脱落。结论钝化膜具有优异的自我修复能力,这是点蚀扩展缓慢的主要原因,且Monel K-500合金能够通过相互吞并、贯通的方式生长。Monel K-500合金点蚀的萌生主要与TiC的析出有关,可通过成分及工艺的优化来控制TiC的数量及分布,进一步提高合金的耐点蚀性能。Research on pitting corrosion characteristics of marine materials have been conducted wildly,however,Monel K-500 alloy,as one of the most important marine corrosion resistant alloys,there is a little research on its pitting characteristics.In order to research the pitting characteristics of Monel K-500 alloy in the seawater,the initiation and growth process of pitting corrosion was studied by scanning vibrating electrode technique(SVET)under constant current mode,and morphology of pit-ting area was characterized by scanning electron microscopy(SEM).SVET results showed that the anodic potential was trans-ferred from the pitting center to the boundary area,and the smaller anode area with more positive potential could be absorbed by larger negative anode area.The SEM results showed that the accumulation of corrosion product on TiC surface,the dissolution of matrix around TiC and the shedding of TiC will appear near the pitting corrosion area.SVET results indicated that passive film of Monel K-500 alloy was with good ability to self-repair,leading to slow expansion of pitting depth.Besides,the growth of Monel K-500 alloy could be in the way to annex and penetrate each other.The SEM results suggested that the pitting corro-sion of Monel K-500 alloy was mainly induced by the precipitation of TiC,so the performance of pitting corrosion resistance of Monel K-500 alloy could be optimized by controlling the amount and distribution of TiC on the aspect of composition and process.

关 键 词：Monel K-500合金 点蚀 SVET SKP 自修复 TIC 

分 类 号：TG172.5[金属学及工艺—金属表面处理]