椰油酸二乙醇酰胺对冷轧钢在二氯乙酸溶液中的缓蚀性能

Corrosion inhibition of coconut diethanolamide on cold rolled steel in dichloroacetic acid solution

采用失重法、动电位极化曲线法研究了非离子型表面活性剂椰油酸二乙醇酰胺对冷轧钢在二氯乙酸(Cl_(2)CHCOOH)溶液中的缓蚀作用;测定各条件下溶液的电导率和表面张力探究加入缓蚀剂后所引起溶液构效性的变化,通过扫描电子显微镜(SEM)、原子力显微镜(AFM)和接触角测试对钢表面微观形貌和亲/疏水性进行了表征分析。结果表明:CDEA对冷轧钢在0.10 mol·L^(-1) Cl_(2)CHCOOH溶液中具有良好的缓蚀作用90 mg·L^(-1) 时最大缓蚀率为95.1%(40 ℃)。CDEA在钢表面的吸附服从Langmuir吸附等温式,其标准吸附Gibbs自由能为-31~-40 kJ·mol^(-1) 。动电位极化曲线表明CDEA为“几何覆盖效应”的混合抑制型缓蚀剂。随着CDEA浓度的增加,表面张力下降,临界胶束浓度(CMC)值为30 mg/L;含CDEA的Cl_(2)CHCOOH水溶液的电导率在钢片腐蚀浸泡后有所下降。缓蚀钢表面表现为疏水性,接触角为95.06°。SEM和AFM微观形貌进一步表明添加CDEA后冷轧钢表面粗糙程度减小,腐蚀程度明显下降。

The corrosion inhibition of the non-inoic surfactant of coconut diethanolamide on cold rolled steel in dichloroacetic acid(Cl_(2)CHCOOH)solution was studied by weight loss and electrochemical methods.The conductivity and surface tension of the solution under various conditions were measured to explore the changes of structure-activity of the solution caused by the addition of corrosion inhibitor.The micro morphology and hydrophilicity/hydrophobicity of steel surface were characterized and analyzed by scanning electron microscope(SEM),atomic force microscope(AFM)and contact angle measurements.The results show that CDEA behaves as a good inhibitor against the corrosion of cold rolled steel in 0.10 mol·L^(-1) Cl_(2)CHCOOH solution.The maximum inhibition efficiency is 95.1%(40℃)at 90 mg·L^(-1) .The adsorption of CDEA on steel follows Langmuir adsorption isotherm,and the standard adsorption free energy is -31~-40 kJ·mol^(-1) .The potentiodynamic polarization curves show that CDEA is a mixed inhibitor via"geometric blocking effect".Along with the increase of CDEA concentration,the surface tension of inhibited solution gradually decreases,and the critical micelle concentration(CMC)is 30 mg·L^(-1) .The conductivity decreases to some extent for the inhibited solution of CDEA after steel immersion.The inhibited steel surface is of hydrophobic with the contact angle of 95.06°.SEM and AFM reveals that after adding inhibitor CDEA,the surface roughness and corrosion degree of cold rolled steel drastically reduced.