木薯淀粉接枝共聚物在HCl溶液中对Al的缓蚀性能研究

Corrosion Inhibition of Cassava Starch Graft Copolymer for Al in HCl Solution

采用失重法、开路电位(OCP)-时间曲线、动电位极化曲线、电化学阻抗谱(EIS)和扫描电子显微镜(SEM)研究了木薯淀粉接枝共聚物(CSGC)在1.0 mol/L HCl溶液中对Al的缓蚀性能。结果表明:CSGC对Al具有良好的缓蚀作用,当用量仅为50 mg/L时缓蚀率可高达90%以上,且在铝表面的吸附符合Langmuir吸附等温式;极化曲线表明CSGC为抑制阴极为主的混合抑制型缓蚀剂;EIS谱在高频区呈容抗弧,在低频区亦出现大段感抗弧,阻抗值随缓蚀剂浓度的增加而增大。SEM表明添加CSGC后Al表面的腐蚀程度会显著降低。

The inhibition effect of cassava starch graft copolymer（CSGC） on the corrosion of Al in solution of 1.0 mol/L HCl was studied by means of methods such as weight loss, open circuit potential（OCP）- time curves, potentiodynamic polarization, electrochemical impedance spectroscopy（EIS） and scanning electron microscope（SEM）. The results show that CSGC acts as a good inhibitor for Al, and the inhibition efficiency is higher than 90% even when the inhibitor concentration is as low as 50 mg/L. The adsorption of CSGC on Al surface obeys Langmuir adsorption isotherm.Polarization curves show that CSGC is a mixed-type inhibitor, while mainly retards the cathodic reaction. EIS spectra consist of large capacitive loop at high frequencies followed by also a large inductive one at low frequencies, while the impedance increases with the concentration of inhibitor.SEM observation confirms the corrosion of Al decreases prominently after the addition of CSGC to the media.