用电化学阻抗谱(EIS)研究环氧树脂涂层的防腐蚀性能

测试了环氧树脂/钢体系在3.5%NaCl溶液中的电化学阻抗谱,并结合激光拉曼光谱测量和扫描电镜观察,系统地研究了有机涂层/金属体系性能与失效过程。重点在于涂层内部腐蚀性介质的传输以及涂层/金属界面发生的变化。结果表明:浸泡初期阻抗减小,中期阻抗增大,后期阻抗又减小,这与界面处生成的腐蚀产物膜有关。随着涂层在电解质溶液中浸泡时间的延长,涂层中Cl-浓度增加,破坏了界面处的腐蚀产物膜。

AN EIS STUDY OF THE ANTICORROSION PERFORMANCE OF EPOXY RESIN COATING

The performance and failure process of organic coating/metal system was studied.The samples with coating immerged in 3.5% NaCl solution were tested by means of electrochemical impedance spectoscopy(EIS),combined with laser lanman spectroscopy(EIS) and scanning electron microscopy(SEM). The emphasis was put on the corrosive medium transportion and the transformation at the interface between coating and metal.The impedance decreased at the beginning of immersion,then increascd in the metaphase of immersion,and again became minished at last,which was related to the formation of corrosion product films.The concentration of Cl-in the coating increased with the immersion going on,resulting in damage of corrosion product.