Abstract:

The corrosion electrochemical behavior of composite coatings system composed of inorganic zinc-rich primer，epoxy middle paste and chlorinated rubber top coating in 3.5% NaCl solution was studied with electrochemical impedance spectroscopy（EIS）.The effect of UV irradiation on the electrochemical behavior was investigated.The results showed that the corrosion process of the composite coatings in 3.5% NaCl solution could be described in the form of four equivalent circuits.The R_c of composite coatings decreased linearly at a rate of 2.2×10⁷ Ω·h^-1 and 808 Ω·h^-1 before and after 120 h respectively，but the C_c of the coatings increased linearly.UV irradiation could accelerate the aging of the coatings but did not affect the electrochemical behavior in the solution.

Key words:

复合涂层, EIS, 老化失效, 紫外辐射

摘要：

采用电化学阻抗谱（EIS）研究了无机富锌底漆/环氧云铁中间漆/氯化橡胶面漆复合涂层体系在3.5%NaCl溶液中的腐蚀电化学行为，考察了紫外辐射对其电化学行为的影响。结果表明：复合涂层体系在3.5%NaCl介质中的腐蚀失效过程可以用4种等效电路来等效。浸泡失效前120 h，电解质溶液电阻R_c从开始的5×10⁹ Ω·cm²以大约2.2×10⁷ Ω·h^-1的速度迅速下降到4×10⁵ Ω·cm²，到浸泡120 h后R_c则以较小的速度808 Ω·h^-1下降，涂层电容C_c是按线性增加。紫外辐射不改变复合涂层体系在3.5% NaCl溶液中的电化学行为，仅仅加速复合涂层的失效。

关键词:

复合涂层, EIS, 老化失效, 紫外辐射