在HCO₃^-浓度为0.08 mol/L及不同浓度配比的SO₄^2-和Cl^-混合溶液中, 利用循环极化电化学测试方法和SEM, 对Cu工作电极的循环极化行为和点蚀表面形貌进行了系统的研究. 结果表明, SO₄^2-或Cl^-均能促进Cu的阳极溶解, 且二者间存在交互作用. Cl^-能降低Cu电极的腐蚀电位, 增强其电化学活性. 在点蚀敏感区域图中, Cu发生点蚀的临界Cl^-浓度为0.02 mol/L. 当Cl^-浓度较低时, SO₄^2-对点蚀敏感性无影响; 当Cl^-浓度为中等时, SO₄^2-抑制点蚀; 当Cl^-浓度较高时, SO₄^2-使Cu点蚀敏感性先升高后降低. 无论SO₄^2-浓度的高低, Cl^-都能促进点蚀. 在本研究体系中, Cu的点蚀敏感性强烈地受到Cl^-和SO₄^2-的影响.

In this work, the pitting corrosion behavior of Cu in the mixed solution of HCO₃^-, Cl^- and SO₄^2- simulating groundwater was investigated by means of cyclic polarization test and SEM microscopy. The results showed that both SO₄^2- and Cl^- can synergistically promote the anodic dissolution of Cu electrode. Cl^- can decrease the corrosion potential of Cu to enhance its electrochemical activity. The plot of pitting sensitivity of Cu showed that the pitting critical concentration of Cl^- was 0.02 mol/L. When the concentration of Cl^- was low, SO₄^2- did not affect the pitting susceptibility; when the concentration of Cl^- was in the middle, SO₄^2- strongly inhibited the pitting corrosion of Cu; when the concentration of Cl^- was high, the pitting susceptibility will first increase and then reduce with increasing the concentration of SO₄^2-. Regardless of what concentration of SO₄^2-, Cl^- can promote the pitting corrosion of Cu. In the current solution system, it is found that the pitting corrosion of Cu was sorely sensitive to SO₄^2- and Cl^-.