摘要
采用动电位极化曲线和电化学阻抗谱研究了酸性红壤模拟液中单宁酸对纯铜接地材料腐蚀行为的影响.结果表明:当单宁酸质量浓度为0.1～4.0 g/L时,随着单宁酸质量浓度的增加,其对铜的缓蚀效率增大;添加单宁酸可有效抑制铜的腐蚀反应过程;在该土壤模拟溶液体系中,单宁酸属于一种阴极缓蚀剂.Mott-Schottky曲线分析结果表明,在酸性红壤模拟液中,铜表面生成的膜具有p型半导体性质,随着单宁酸质量浓度增加,受主浓度降低,铜表面膜层的耐蚀性更强.单宁酸分子在铜表面的吸附最趋向Langmuir吸附模型,当单宁酸质量浓度为0.1～4.0 g/L时,其在铜表面的吸附自由能小于0,大于-40 kJ/mol,单宁酸在铜表面发生的是自发进行的物理吸附过程.
Abstract
The effect of tannic acid on the corrosion behavior of pure copper grounding materials in an acidic red soil simulation solution was studied using potentiodynamic polarization curves and electrochemical impedance spectroscopy.The results show that when the mass concentration of tannic acid was 0.1-4.0 g/L,its corrosion inhibition efficiency on copper increased with the increase of tannic acid mass concentration.Adding tannic acid could effectively inhibit the corrosion reaction of copper.In the soil simulated solution system,tannic acid belonged to a cathodic corrosion inhibitor.The results of the Mott Schottky curve analysis indicat that in the acidic red soil simulation solution,the film formed on the copper surface had p-type semiconductor properties.As the concentration of tannic acid increased,the acceptor concentration decreased,and the corrosion resistance of the film layer on the copper surface was strong.The adsorption of tannic acid molecules on the copper surface tended to follow the Langmuir adsorption model.When the mass concentration of tannic acid was 0.1-4.0 g/L,its adsorption free energy on the copper surface was less than 0 and greater than-40 kJ/mol.Tannic acid undergoed a spontaneous physical adsorption process on the copper surface.
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