Abstract A novel environment-friendly composite coating (P/P'-Ch-P/P') was prepared by layer-by-layer assembly of polyvinyl butyral (PVB), polymethylhydrosiloxane (PMHS) and chitosan (Ch) on AA 2024 substrate to improve the corrosion resistance of AA 2024 sample. The properties of the coatings were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM) and laser confocal microscope. The results showed that the addition of PMHS increased the hydrophobicity of composite coating；as the intermediate layer, Ch also crosslinked other components while forming the film. At the same time, the corrosion resistance of the coating in 3.5 wt.% NaCl solution was characterized by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization. Compared with the bare aluminum substrates, the impedance modulus of the composite coating was increased by 3 orders of magnitude; the corrosion current density (Icorr) of the composite coating was reduced by 5 orders of magnitude. The results of long-term immersion test showed that the composite coating still had good anticorrosion ability after 60 days. This study provides a simple and environment-friendly method for corrosion protection of aluminum alloy in marine environment.

中文翻译：

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聚乙烯醇缩丁醛（PVB）/聚甲基氢硅氧烷（PMHS）/壳聚糖（Ch）环保组装涂料的防腐性能

摘要 通过聚乙烯醇缩丁醛（PVB）、聚甲基氢硅氧烷（PMHS）和壳聚糖（Ch）在AA 2024基材上逐层组装制备了一种新型环保复合涂层（P/P'-Ch-P/P'）。提高AA 2024样品的耐腐蚀性。通过傅里叶变换红外光谱（FT-IR）、扫描电子显微镜（SEM）和激光共聚焦显微镜对涂层的性能进行了表征。结果表明，PMHS的加入提高了复合涂层的疏水性；Ch作为中间层，在成膜的同时也交联了其他组分。同时，通过电化学阻抗谱（EIS）和动电位极化表征了涂层在 3.5 wt.% NaCl 溶液中的耐腐蚀性能。与裸铝基板相比，复合涂层的阻抗模量提高了3个数量级；复合涂层的腐蚀电流密度 (Icorr) 降低了 5 个数量级。长期浸泡试验结果表明，复合涂层在60天后仍具有良好的防腐能力。该研究为铝合金在海洋环境中的腐蚀防护提供了一种简单、环保的方法。