When aluminum alloy is present in a Cl−-rich environment, the surface oxide film is easily damaged, resulting in faster dissolution of the substrate. The application of graphene-modified anticorrosion coating can effectively prevent the occurrence of corrosion. In this study, to explore the corrosion resistance of graphene-modified anticorrosion coating on the surface of aluminum alloy, we prepared graphene-modified anticorrosion coating on the surface of aluminum alloy and investigated the corrosion resistance mechanism. Epoxy resin primer and polyurethane top coat were modified by predispersed reduced graphene oxide (rGO). Scanning electron microscope (SEM) and Raman spectrum were used to investigate the microstructure of graphene-modified anticorrosion coating, and it was found that the addition of rGO could effectively improve the porosity defect of epoxy resin primer. Electrochemical workstation was used to quickly characterize the corrosion resistance of graphene-modified anticorrosion coating, and the change of the electrochemical curve during soaking in 3.5% NaCl was investigated every 5 hours. It was found that the application of rGO to modify the anticorrosion coating could improve the corrosion resistance of the anticorrosion coating, and as the soaking time increased, the corrosion resistance of graphene-modified anticorrosion coating changed regularly. The study results indicated that when the content of rGO was 0.4%, the porosity of epoxy coating decreased from 1.54% to 0.33%, the porosity dropped by an order of magnitude, and the self-corrosion voltage was relatively positive (-0.72434 V). The self-corrosion current density was the lowest ( ), and at the low frequency, the impedance modulus was the highest (103). After the equivalent circuit fitting, the dispersion index was relatively high, the dispersion effect was relatively weak, and the corrosion resistance of the coating was improved. For graphene-modified anticorrosion coating, in the early stage of corrosion protection, the existence of pores and other defects in the coating might increase the dispersion effect, resulting in greatly decreased corrosion resistance of the coating. In the middle stage of corrosion protection, the pores in the coating would be completely filled by corrosive ions, resulting in a weakened dispersion effect. Therefore, the decrease in the corrosion resistance of the coating was slowed down and became stable.

中文翻译：

---

石墨烯改性防腐涂料的制备及其耐腐蚀机理研究

当铝合金存在于富Cl-环境中时，表面氧化膜容易损坏，导致基体更快溶解。石墨烯改性防腐涂层的应用可以有效防止腐蚀的发生。本研究为探究铝合金表面石墨烯改性防腐涂层的耐腐蚀性能，在铝合金表面制备了石墨烯改性防腐涂层，并研究了其防腐机理。环氧树脂底漆和聚氨酯面漆通过预分散还原氧化石墨烯 (rGO) 进行改性。使用扫描电子显微镜（SEM）和拉曼光谱研究石墨烯改性防腐涂层的微观结构，发现加入rGO可以有效改善环氧树脂底漆的气孔缺陷。采用电化学工作站快速表征石墨烯改性防腐涂层的耐腐蚀性能，每5小时考察一次在3.5% NaCl浸泡过程中电化学曲线的变化。发现应用rGO对防腐涂层进行改性可以提高防腐涂层的耐腐蚀性能，并且随着浸泡时间的增加，石墨烯改性防腐涂层的耐腐蚀性能有规律地变化。研究结果表明，当rGO含量为0.4%时，环氧涂层的孔隙率由1.54%下降到0.33%，孔隙率下降一个数量级，自腐蚀电压相对正(-0.72434 V) . 自腐蚀电流密度最低（ ），在低频时，阻抗模量最高（103）。等效电路拟合后，分散指数较高，分散作用较弱，涂层的耐腐蚀性能有所提高。对于石墨烯改性防腐涂层，在腐蚀防护的早期，涂层中气孔等缺陷的存在可能会增加分散效应，导致涂层的耐腐蚀性能大大降低。在腐蚀防护的中期，涂层中的孔隙会被腐蚀性离子完全填满，导致分散作用减弱。因此，涂层耐蚀性的下降减缓并趋于稳定。