ZrO2-anchored rGO nanohybrid for simultaneously enhancing the wear resistance and anticorrosion performance of multifunctional epoxy coatings

ZrO2 nanoparticles were controllably anchored on the surface of rGO nanosheets via an environmentally friendly single-step hydrothermal reaction and then incorporated into epoxy coatings to simultaneously improve the wear resistance and anticorrosion performance of the coatings. Based on the structural characterization and analysis, ZrO2 nanoparticles were homogeneously anchored on the surface of rGO through the charge attraction between GO and the Zr(IV) complex ions in the precursor. The addition of 0.5 wt% ZrO2@rGO nanohybrids to the epoxy resin coating (ZrO2@rGO/EP) significantly improved the adhesion strength, impact resistance and surface hardness. Tribological investigation revealed that the average friction coefficient of ZrO2@rGO/EP decreased by 41.96% and the wear resistance improved by 57.69%. Characterization of the worn surface indicated that the main wear mechanism of ZrO2@rGO/EP was abrasive wear with smooth and slightly damaged surface morphology. The anti-wear improvement is attributed to the filling effect of small wear debris of ZrO2@rGO/EP on the groove and the loading effect of hard ZrO2@rGO nanohybrid debris. SEM images and EDS line scan of worn surfaces of the friction counterparts confirmed the friction transfer effect of ZrO2@rGO/EP. After the ZrO2@GO/EP was soaked in 3.5 wt% NaCl solution for 7 days, the impedance modulus reached 2.50 × 106 Ωcm2, one order of magnitude higher than that of pure EP. The phase angle (105 Hz) was close to 90°, almost twice that of pure EP. The Rc value fitted via Zview software was two orders of magnitude higher. Electrical equivalent circuit models indicated the enhanced anti-corrosion performance. The as-prepared ZrO2@rGO hybrid in EP coatings could effectively prevent electrolyte penetration, and ZrO2 nanoparticles played a synergistic role with rGO nanosheets in alleviating corrosion. It provides a controllable and effective strategy for developing multifunctional ceramic/graphene/organic coatings with enhanced wear resistance and anti-corrosion performance.