关键词: 水性涂层, 铝粉, 腐蚀, 自修复, 电化学阻抗谱, 扫描振动电极技术

Abstract: The corrosion electrochemical behavior of a water-borne epoxy coating pigmented with aluminum flake on carbon steel with artificial scratch defect was studied in 3.5% NaCl solution using electrochemical impedance spectroscopy(EIS)and scanning vibrating electrode technique(SVET).The results indicated that the defect presented anodic electroactivity at the initial stage of immersion,which extended gradually with time from the scratch into the neighboring coating,lowering the coating impedance.With further immersion,however,the electroactivity of the coating/steel interface decreased significantly due to the self-repairing of the corrosion products,causing an obvious increase of the coating impedance.In the later period of immersion,more scattered electroactive areas appeared under the coating because of the penetrating of corrosive species to the surface of substrate,which led to the decrease of coating impedance,showing the delamination and damage of the coating.

Key words: water-borne coating, aluminum flake, corrosion, self-repairing, EIS, SVET