飞机结构铝合金PPy/rGO复合镀层及其防腐蚀性能

Corrosion Resistance of PPy/rGO Composite Coating on Aluminum Alloy for Aircraft Structure

为研究氧化石墨烯(GO)与聚吡咯(PPy)复合镀层的防腐性能,采用恒电位法在铝合金片上电化学聚合吡咯单体,形成PPy镀层,再在PPy镀层表面电镀GO形成聚吡咯/还原氧化石墨烯(PPy/rGO)复合镀层。采用SEM、Raman以及FTIR对镀层的微观形貌与结构成分进行表征,采用接触角测量仪测试镀层的疏水性能,通过极化曲线、电化学阻抗谱(EIS)分析镀层的防腐蚀性能。结果表明:PPy/rGO复合镀层表面的rGO镀层覆盖PPy镀层表面的针孔、凹槽等缺陷,使复合镀层表面光滑、平整,屏蔽性能增强;疏水性能也得到提高。PPy/rGO复合镀层腐蚀电流密度比PPy镀层、铝合金小,表明其腐蚀速率低。PPy/rGO复合镀层比PPy镀层与铝合金拥有更大的阻抗弧,说明PPy/rGO复合镀层对溶液中电解质离子有更强的阻碍作用。铝合金和PPy镀层出现不同程度的腐蚀现象,而PPy/rGO复合镀层并未发生明显的腐蚀现象,说明PPy/rGO复合镀层防腐蚀性能更好。

To study the corrosion resistance of the composite coating between GO and polypyrrole, a polypyrrole(PPy)coating was prepared by electrochemical polypyrrole monomer on Al sheet through potentiostatic method. The polypyrrole/reduced graphene oxide(PPy/rGO) composite coating was then formed by electroplating graphene oxide solution on the surface of the PPy coating. SEM, Raman and FTIR were used to characterize the microstructure and composition of the coating. Hydrophobicity of the coating was tested by using the contact angle measuring instrument. The corrosion resistance of the coating was analyzed by polarization curve and EIS. The results show that the rGO coating covers the defects on the surface of the PPy coating, which makes the surface of composite coating level and smooth. PPy/rGO composite coating shows good hydrophobicity than the PPy coating. The corrosion current density of the PPy/rGO composite coating is smaller than that of the PPy coating and Al, indicating that the corrosion rate is lower. Compared with the PPy coating and Al,PPy/rGO composite coating has larger impedance arc, which indicates the PPy/rGO composite coating has stronger hindrance to electrolyte ion in solution. Al and PPy coatings are corroded to different degrees, however, the PPy/rGO composite coatings has no obvious corrosion Phenomenon. Therefore, the PPy/rGO composite coating has better corrosion resistance.