缝隙几何尺寸对闭塞区化学环境及腐蚀行为的影响  

Effect of Crevice Geometry on Chemical Environment of Crevice Solution and Corrosion Behavior of 2205 Duplex Stainless Steel

作　　者：许志昱 胡骞[1] 黄峰[1] 刘静[1] 卢献忠 XU Zhiyu;HU Qian;HUANG Feng;LIU Jing;LU Xianzhong(Hubei Engineering Technology Research Center of Marine Materials and Service Safety,State Key Laboratory of Refractories and Metallurgy,Wuhan University of Science and Technology,Wuhan 430081,China;Shanghai Baosteel Casting Co.,Ltd.,Shanghai 201900,China)

机构地区：[1]武汉科技大学、省部共建耐火材料与冶金国家重点实验室、湖北省海洋工程材料及服役安全工程技术研究中心,武汉430081 [2]上海宝钢铸造有限公司,上海201900

出　　处：《中国腐蚀与防护学报》2024年第6期1581-1588,共8页Journal of Chinese Society For Corrosion and Protection

基　　金：湖北省重大攻关项目(JD)(2023BAA003)。

摘　　要：针对2205双相不锈钢在NaCl溶液中的缝隙腐蚀行为,设计缝内溶液化学环境测试及电化学实验装置,研究了缝隙腐蚀孕育期内Cl~-和H^(+)的富集规律,以及发展期缝内电极的阳极溶解行为,探讨了缝隙高度和闭塞区体积对闭塞区化学环境和腐蚀行为的影响。结果表明,随着缝隙高度或闭塞区体积减小,在缝隙腐蚀孕育期,Cl~-和H^(+)富集速率明显上升,H^(+)浓度增加2个数量级。而在缝隙腐蚀发展期,OH^(-)浓度显著增大;而缝内电位降越小,缝内电极的阳极溶解速率就越大。The chemical composition of the solution inside the crevice influences the initiation and development of crevice corrosion significantly,and the crevice geometry is an important factor which determines the chemical composition of the solution inside the crevice.Herein,the crevice corrosion behavior of 2205 duplex stainless steel in a NaCl solution was investigated by means of a home-made set for measurement of the solution composition and electrochemistry inside the crevice.The variation of Cl^(-)and H^(+)concentration during the crevice corrosion incubation period,and the anodic dissolution behavior of the electrode inside the crevice during the development period were characterized.Further,the effect of crevice gap size and solution volume of occluded area on the solution composition and corrosion behavior of occluded area were revealed.Results show that with the decrease of crevice gap or solution volume of occluded area,the enrichment rate of Cl^(-)and H^(+)increase significantly and the concentration of H^(+)increases by 2 orders of magnitude.The anodic dissolution rate of electrode inside crevice increases with the decrease of the potential drop inside the crevice.

关 键 词：缝隙腐蚀 不锈钢 闭塞区 

分 类 号：TG172[金属学及工艺—金属表面处理]