吐温-60对钢在Cl_(2)CHCOOH溶液中的缓蚀性能

Inhibition action of tween-60 on the corrosion of steel in Cl_(2)CHCOOH solution

通过失重法、动电位极化曲线和电化学阻抗谱(EIS)研究了非离子表面活性剂吐温-60在0.10 mol·L^(-1)二氯乙酸(Cl_(2)CHCOOH)溶液中对冷轧钢的缓蚀性能,并且采用扫描电子显微镜(SEM)、原子力显微镜(AFM)和接触角测试对冷轧钢表面的微观形貌和亲水/疏水性进行了表征分析。结果表明:20℃时100 mg·L^(-1)吐温-60的缓蚀率可达89.6%,6~48 h内缓蚀效果稳定;20~50℃时吐温-60在冷轧钢表面的吸附符合Langmuir吸附等温式,标准吸附Gibbs自由能为-42.92~-47.41 kJ·mol^(-1),吸附过程中伴随着熵增加。动电位极化曲线表明吐温-60为“几何覆盖效应”的混合抑制型缓蚀剂;随着吐温-60浓度的增大,Nyquist图的容抗弧半径增大,电荷转移电阻增大,而界面双电层电容值下降。SEM和AFM的微观表面形貌进一步证实了吐温-60能有效减缓钢表面的腐蚀程度;缓蚀后钢表面接触角增大,表面疏水性增强,可有效屏蔽酸介质对钢表面的腐蚀。

The corrosion inhibition performance of nonionic surfactant of tween-60 on cold rolled steel in 0.10 mol·L^(-1)dichloroacetic acid(Cl_(2)CHCOOH)solution was studied by weight loss method,potentiodynamic polarization curves and electrochemical impedance spectroscopy(EIS).Scanning electron microscopy(SEM),atomic force microscopy(AFM),and contact angle measurements were used to fully characterize the microscopic morphology and hydrophilic/hydrophobic property of the cold rolled steel surface.The results showed that the inhibition efficiency of 100 mg·L^(-1)tween-60 at 20℃can reach as high as 89.6%.The inhibition performance remains stable in 6~48 h.The adsorption of tween-60 on steel surface obeys Langmuir adsorption isotherm at 20~50℃,and the standard adsorption Gibbs free energy was-42.92~-47.14 kJ·mol^(-1).The adsorption process was accompanied by the increase of entropy.Potentiodynamic polarization curves showed that tween-60 was a mixed-type inhibitor via“geometric coverage effect”.Along with the increase of the concentration of tween-60,the capacitive arc radius of the Nyquist diagram and the charge transfer resistance increased,but the electric double layer capacitance decreased.SEM and AFM microscopic graphs of CRS surfaces further confirmed that tween-60 could efficiently retard the corrosion of steel surface.The contact angle of the inhibited steel surface increased,and the surface hydrophobicity was strengthened,which could effectively shield the corrosion of the steel surface by the acid medium.