聚吡咯/聚多巴胺的电化学合成及其对铝合金耐蚀性的影响

为了提高铝合金有机涂层的耐蚀性，通过电化学方法在7075铝合金表面制备了海岛结构的聚吡咯（PPy）/聚多巴胺（PDA）复合涂层，利用FE-SEM、原子力显微镜、FTIR分析了PPy/PDA涂层的表面形貌、表面粗糙度和化学成分，并通过交流阻抗图谱分析了涂层的阻抗特性，通过极化曲线分析了具有PPy/PDA涂层的铝合金的极化电压和极化电流，研究其耐蚀特性。结果显示，通过一步法电化学聚合方法，吡咯和多巴胺在铝合金表面同时发生电化学聚合，生成PPy/PDA复合涂层，PPy/PDA涂层具有海岛结构，纯PPy和PPy/PDA涂层的粗糙度分别是（74.582±7.227）nm和（73.740±7.811）nm。交流阻抗和极化曲线说明PPy/PDA涂层相比于纯PPy涂层具有更大的阻抗力，PPy/PDA涂层的腐蚀电流和腐蚀电压分别是4.1825×10-6 Acm-2和-0.6919 V，相对于纯PPy（腐蚀电流和腐蚀电压分别是7.618×10-6 Acm-2和-0.7403 V）具有更好的防腐特性。 

Electrochemical synthesis of polypyrrole/polydopamine for aluminum alloy corrosion inhibition

Polypyrrole(PPy)/polydopamine(PDA) coating was prepared on the surface of 7075 aluminum alloy through electrochemical polymerization to improve the corrosion resistance of aluminum alloy organic coatings. FE-SEM, atomic force microscope and FTIR were used to analyze the surface morphology, surface roughness and chemical composition of PPy/PDA coating, respectively. AC impedance spectroscopy was applied to study the impedance characteristics of the coating. The polarization voltage and polarization current of the aluminum alloy coated with PPy/PDA were analyzed by polarization curves to study the corrosion resistance. The research shows that pyrrole and dopamine simultaneously electrochemically polymerize on the aluminum alloy surface by one-step electrochemical polymerization. PPy molecular chains and PDA molecular chains form network interpenetrating structure. PPy/PDA coating has a sea-island structure with a surface roughness of (73.740±7.811) nm, which is close to the roughness of the pure PPy coating (74.582±7.227) nm. The polarization curves indicate that the corrosion current and corrosion voltages of the coated PPy/PDA coating are 4.1825×10^-6 Acm^-2 and -0.6919 V, respectively. And the corrosion current and corrosion voltages of the pure PPy are 7.618×10^-6 Acm^-2 and -0.7403 V, respectively.