碳钢表面置换铜镀层的生长机理及其耐蚀性

Growth Mechanism and Corrosion Resistance of Replacement Copper Coating on Carbon Steel Surface

采用自研的置换镀铜液,在20号碳钢表面制备了铜镀层。通过电化学测试,研究了置换镀铜时间对铜镀层耐蚀性的影响,并分析了铜镀层的生长规律。结果表明:随着置换镀铜时间的延长,铜镀层的自腐蚀电位正移,自腐蚀电流密度减小,电荷转移电阻(Rct)显著增大;当置换镀铜时间为16h时,Rct值最大,铜镀层的耐蚀性最好;置换铜镀层的生长过程分为3个阶段,初期形成阻挡层和多孔层,中期形成阻挡层、致密层和多孔层,后期形成阻挡层和致密层。

Copper coating was prepared on surface of the 20#carbon steel by self-developed displacement copper plating solution.The effect of replacement copper plating time on the corrosion resistance of copper coating was studied by electrochemical test,and the growth regulation of copper coating was analyzed.The results show that with the increase of replacement copper plating time,the free corrosion potential of the coating shifted positively,the free corrosion current density decreased,and the charge transfer resistance(Ret)increased significantly.When the replacement copper plating time was 16 h,Ret value was the largest,and the corrosion resistance of copper coating was the best.The growth of the replacement copper coating was divided into three stages.In the early stage,a barrier layer and a porous layer were formed.In the middle stage,a barrier layer,a dense layer and a porous layer were formed.In the later stage,a barrier layer and a dense layer were formed.