采用电化学阻抗谱(EIS)对有机硅环氧树脂涂层/LY12铝合金在海水中的腐蚀行为进行了研究, 并提出了涂层/金属体系在不同浸泡阶段的阻抗模型, 同时采用电容法分析了失效过程中水分的吸收问题及水分的扩散系数。结果表明, 在海水环境中, 有机硅环氧树脂涂层表面覆盖了一层致密的腐蚀产物, 有效地阻止了腐蚀介质向涂层内部的进一步渗透。涂层的吸水过程可分为两个阶段, 即线性增加阶段和缓慢增加并趋于平稳阶段, 并计算出有机硅环氧涂层中海水的扩散系数D=0.605 22×10-9 cm2·s-1。

The corrosion behavior of LY12 aluminum alloy based silicone-epoxy hybrid coating in seawater was investigated by using electrochemical impedance spectroscopy (EIS) and the impedance model which adapted coating/metal systems at different phase of immersion was proposed. The absorption and the diffusion coefficient of moisture in the failure process were studied by the method of capacitance analysis. The results showed that in the sea water environment, silicone epoxy coating surface can be covered with a layer of dense corrosion products, which can prevent the corrosion medium to penetrate into the internal coating effectively. Absorbent coating process can be divided into two phases: the linear increase phase and the increased and stabilized phase. Finally, the diffusion coefficient D of water of the silicon-epoxy hybrid coatings in seawater was calculated, D=0.605 22×10-9 cm2·s-1.