Enhancing corrosion resistance of Q355B steel in marine environments using graphene doped inorganic zinc-rich coatings

Prolonged exposure of Q355B steel to the marine environment renders it susceptible to corrosion from seawater salt spray. In this study, inorganic zinc-rich coatings incorporating different components of graphene and calcium carbonate as anti-corrosion strategy were designed and aimed to improving their corrosion resistance. The anti-corrosion performance of these coating on Q355B was evaluated using scanning electron microscopy (SEM), X-ray diffraction (XRD), Potentiodynamic polarization tests and electrochemical impedance spectroscopy. Results indicated that the coating of 2G-1.5CaCO₃-ZRC exhibited a corrosion current density of 1.565 × 10⁻⁵A cm⁻² and an impedance value of 734.6 Ω after immersion in simulated seawater solution for seven days. Compared with the untreated coating, this formulation demonstrated reduced corrosion current density and increased impedance values, indicating that the incorporation of graphene and calcium carbonate effectively mitigated corrosion rates while prolonging the materials protection duration. This work delivers the potential application in the field of protection for metal structures in seaport areas.