铝合金表面有机硅环氧涂层的腐蚀电化学行为

研究了铝合金/有机硅环氧涂层电极在5%NaCl(质量分数)溶液中的腐蚀电化学行为,提出了涂层体系在浸泡过程中的不同阻抗模型。结果表明,该涂层体系的作用过程可分为3个阶段:浸泡初期为涂层吸水,中期为烷氧基硅烷的水解和缩聚,后期主要为阻挡层保护。阻抗参数解析表明,涂层中硅烷的水解与缩聚增强了涂层的致密度和交联度,从而使涂层体系在浸泡过程中可实现修复和自愈(或逆损伤)。

Electrochemical Corrosion Behavior of Silicone-epoxy Hybrid Coatings on LY12 Aluminum Alloy Electrode

Corrosion behavior of LY12 aluminum alloy electrodes coated with silicone-epoxy hybrid coating in 5%NaCl solution was investigated by means of electrochemical impedance spectroscopy (EIS) measurement, while impedance models related to different immersion stages were also proposed. The results indicated that the reaction process of the coating during immersion presented three stages: the initial stage, water was absorbed in the silicone-epoxy hybrid coating; the middle stage, the hydrolysis and poly-condensation of alkoxy-silicone occurred in the coating; and then the coating acted as a protective barrier in the third stage. Analysis of the impedance parameters revealed that the silicone hydrolysis and poly-condensation enhanced the density and the degree of crosslinking of the coating. Therefore, during immersion the coating systems exhibited characteristics of inherent repairing or re-healing.