海水中Al(OH)_3对稀土铝热浸镀层腐蚀行为的影响  

Effect of Aluminum Hydroxide in Seawater on Corrosion Behavior of Hot-Dipped Rare Earth-Aluminum Coating

作　　者：臧贝妮[1,2] 孙虎元[1] 王巍[1,2] 孙立娟[1] 

机构地区：[1]中国科学院海洋研究所,山东青岛266071 [2]中国科学院研究生院,北京100049

出　　处：《材料保护》2011年第7期18-19,34,共3页Materials Protection

基　　金：国家自然科学基金项目(40776044)资助

摘　　要：目前有关热浸镀铝层在海水中形成的初级腐蚀产物Al(OH)3对镀层后续腐蚀影响的研究较少。向海水中添加Al(OH)3使其饱和,将Q235钢稀土铝热浸镀试样浸入其中,采用失重法、扫描电镜(SEM)、极化曲线和交流阻抗谱研究了海水中Al(OH)3对稀土铝热浸镀层腐蚀行为的影响。结果表明:热浸镀试样在添加了Al(OH)3的海水中的腐蚀速率比在未添加Al(OH)3的海水中的大,表面腐蚀严重;Al(OH)3使阴极反应阻力减小,诱导点蚀反应,加速腐蚀,导致被Cl-破坏的钝化膜无法及时修复,从而加重镀层的腐蚀。Al(OH)3 was added into seawater to form a saturated solution,and then Q235 steel coated with hotdipped rare earth-Al(RE-Al)coating was immersed into the resultant seawater.The corrosion behavior of the coating was investigated based on weight loss tests,scanning electron microscopic observation and electrochemical tests(polarization curve and electrochemical impedance spectroscopy).It was found that hotdipped RE-Al coating had a higher corrosive rate and experienced severer surface corrosion in seawater containing saturated Al(OH)3 than in common seawater.Al(OH)3 added in seawater decreased resistance of cathodic reaction,induced pitting corrosion,accelerated corrosion and retarded repair of the passivation film destructed by Cl-,causing severe corrosion of the coating.

关 键 词：海水腐蚀 AL(OH)3 热浸镀 稀土铝 

分 类 号：TG172.5[金属学及工艺—金属表面处理]