Size Effect of Graphite Nanosheet-Induced Anti-Corrosion of Hydrophobic Epoxy Coatings

In order to broaden the selectivity of graphite nanosheet additives on epoxy resin-based coatings and verify the size effect, this work aims to dope graphite nanosheets of different sizes into the three-dimensional structure produced by cross-linking and curing epoxy resin and polyamide resin. In addition, a micro-nano level secondary structure and a surface with special roughness are constructed to obtain the composite epoxy hydrophobic coating. The influence of the size effect of graphite nanosheets on the hydrophobic performance and corrosion resistance of the coating is summarized as well. Among them, the optimized doping size (2.2 μm) of graphite nanosheets in the epoxy coating showed the largest impedance arc of 2.58 × 108Ω cm2, which could form an excellent nano-network covering the micropores to impede the diffusion of corrosive medium. Through simulation calculation analysis, we also found that the edge site of graphene is more effective in capturing H2O and O2; therefore, a smaller size of graphene with a large edge can be more favorable. This work will be used as a reference for the industrial application of graphite anti-corrosive coating.