2A12铝合金表面有机复合涂层的耐蚀性能研究

Corrosion Resistance of Organic Composite Coatings on 2A12 Aluminum Alloy

以氟碳面漆、丙烯酸聚氨酯面漆、环氧玻璃鳞片胶泥中间漆、铝合金防腐底漆和底面合一铝合金专用防腐漆为原料,采用不同的配套方案在2A12铝合金表面制备了有机复合涂层,通过扫描电子显微镜(SEM)、中性盐雾实验、极化曲线测试和电化学阻抗谱(EIS)测试对有机复合涂层的耐蚀性能和耐蚀机理进行了研究。结果表明:有机复合涂层与2A12铝合金基体之间,以及有机复合涂层中各层之间均结合良好;中性盐雾腐蚀30 d后各有机复合涂层仍具有表面光泽,没有出现开裂和剥落;(底漆+中间漆+氟碳面漆)方案的有机复合涂层耐蚀性能最佳,使腐蚀电流密度下降了3个数量级,极化电阻上升了3个数量级,阻抗值提升约2个数量级。

Organic composite coatings were prepared on the surface of 2A12 aluminum alloy with fluorocarbon paint, acrylic polyurethane paint, epoxy glass flake paint, acrylic polyurethane paint, anti-corrosion primer and aluminum alloy-specific paint as ingredients according to different combinations of paints. The corrosion behavior of the prepared organic composite coatings was assessed by means of neutral salt spray accelerated corrosion test, polarization curve measurement, electrochemical impedance spectroscopy（EIS） and scanning electron microscopy（SEM）. The results showed that the adhesion between the organic composite coatings and the Al-alloy substrate was excellent as well as the adhesion between each layer of organic composite coating. After 30 d neutral salt spray corrosion, every organic composite coating still kept the surface gloss fairly well, and there was no cracking and spalling to be detected on the coating surface. The organic composite coating consisted of fluorocarbon paint, epoxy glass flake paint and anti-corrosion primer had the best corrosion resistance, and the corrosion current density decreased by 3 orders of magnitude, the polarization resistance increased by 3 orders of magnitude and the impedance value roughly enhanced by 2 orders of magnitude, compared with 2A12 aluminum alloy.