天然海水中铜离子的添加对EH40钢腐蚀的影响

目的 研究天然海水中添加1.5、15 mmol/L铜离子对EH40钢腐蚀速率、腐蚀产物形貌及成分的影响规律,并揭示其作用机制.方法 采用天然海水实验室挂片的方式进行4周的腐蚀实验,定期对试样进行表征,并检测海水环境参数.结果 在海水中添加1.5、15 mmol/L铜离子后,EH40钢的腐蚀速率加快,同时表面腐蚀产物出现特殊分层现象,并包含铜单质层.结论 海水中添加1.5、15 mmol/L铜离子,对EH40钢腐蚀的促进作用主要通过三种机制,铜离子水解形成酸性腐蚀环境、铁和铜离子的置换反应消耗试样基体、Fe-Cu电偶腐蚀池加速阳极铁的溶解.

Effect of Adding Copper Ion on Corrosion of EH40 Steel in Natural Seawater

The purpose of this paper is to study the effect of adding 1.5, 15 mmol/L copper ion in natural seawater on the corrosion rate, corrosion product appearance and composition of EH40 steel systematically and propose the influence mechanism. The corrosion experiment of natural seawater was carried out by coupon method in the laboratory for 4 weeks, and the samples were characterized regularly and seawater environmental parameters were detected. After 1.5, 15 mmol/L copper ions are added into seawater, the corrosion rate of EH40 steel is accelerated. Meanwhile, surface corrosion products are stratified and one copper layer appears. The addition of 1.5, 15 mmol/L copper ions promotes the corrosion of EH40 steel in seawater mainly through three mechanisms:the acidic corrosive environment formed by the hydrolysis of copper ions, the consumption of sample matrix by the replacement reaction between iron and cooper ions, and anodic dissolution of iron accelerated by Fe-Cu galvanic corrosion.