Deterioration behavior of graphene-modified epoxy-primer-coated aluminum alloy in a UVA acidic alternation immersion environment

The modification of epoxy primers with graphene can significantly improve their anticorrosion properties and reduce environmental pollution. In this study, the modified epoxy primers with different graphene contents were prepared and tested in a UVA acidic alternation immersion environment. The deterioration characteristics under different corrosion times were analyzed in terms of their microscopic morphology, electrochemical characteristics, and molecular structure. It was shown that graphene nanoplates can impede the penetration of corrosive media, promote the cathodic protection of fillers, and easily cross-link with amino radicals to improve the binding force at the interface. The coated surface of graphene nanoplates with a content of 1.0 wt% was flatter than those with a content of 0.5 wt% and 2.0 wt%. After corrosion, the roughness of the surfaces all increased significantly. Especially, the coatings with graphene contents of 0.5 wt% increased nearly three times. And the impedance improvement of the coatings with graphene contents of 0.5 wt% and 1.0 wt% is more significant, both reaching more than 6 × 1011 Ω·cm2. The most obvious corrosion inhibiting effect was the coatings with a graphene content of 1.0% wt.