A binder-free Graphene-Al2O3 composite coating for dual-Function metal protection

Conductive anticorrosion coatings are critical for protecting metal infrastructure in power systems. However, integrating high conductivity with durable corrosion resistance—especially in binder-free systems—remains challenging, as conventional polymer binders often hinder charge transport and degrade structural stability. Here, we present a binder-free graphene-Al₂O₃ composite coating prepared via a synergistic electrodeposition–electrophoresis strategy. In this architecture, graphene nanosheets form a continuous conductive network on Q235 carbon steel, while Al₂O₃ nanoparticles enhance corrosion resistance by strengthening the barrier effect. Electrochemical analysis reveals that the optimized coating (1000 s deposition) lowers corrosion current density by 66 % and increases polarization resistance nearly fourfold, compared to bare steel. Notably, the coating maintains metallic-level conductivity (3.72 × 10⁶ S/m), with only a 2.26 % reduction from the uncoated substrate. These results highlight the dual-functional performance of the graphene-Al₂O₃ system and offer a promising route toward next-generation conductive anticorrosion coatings for energy and infrastructure applications.