RGO/epoxy composite coatings as a dual barrier: Microstructural insights into superior wear and corrosion resistance

This study investigates the enhancement of wear resistance, corrosion protection, and long-term stability of epoxy resin coatings on steel through the incorporation of reduced graphene oxide (RGO) nanosheets. RGO/epoxy composite coatings with varying RGO contents (0, 0.05, 0.1, 0.5, and 1.0 wt%) were fabricated and systematically evaluated. Among them, the coating containing 0.1 wt% RGO exhibited the best wear resistance, achieving the lowest wear rate (3.17 × 10⁻⁸ mm³ N⁻¹ s⁻¹), attributed to the synergistic effects of lubrication and enhanced crosslinking. In addition, the 0.1 wt% RGO coating demonstrated superior corrosion resistance, with a significantly improved corrosion potential (Ecorr = −0.285 V). This improvement was ascribed to the uniform dispersion of RGO within the epoxy matrix and the “maze effect,” which enhanced both barrier performance and interfacial adhesion. Long-term immersion tests in saline and simulated marine environments confirmed that the 0.1 wt% RGO coating maintained excellent protective performance and structural integrity over 10 weeks, significantly outperforming the pure epoxy coating. However, higher RGO contents (≥ 0.5 wt%) led to nanosheet aggregation, resulting in microcrack formation and performance degradation, highlighting the critical importance of optimizing both RGO content and dispersion. These findings provide valuable insights into the application of two-dimensional nanomaterials in protective composite coatings and offer practical guidance for the development of high-performance, corrosion-resistant, and wear-resistant coating systems.