Optimization of a graphene oxide–zinc oxide composite in epoxy resin as a corrosion protection material

Using nanomaterials such as graphene and zinc derivatives in epoxy coatings has shown increased corrosion resistance, durability, and barrier properties. However, their real-world application is limited due to their limited lifespan, high conductivity rate, high sacrificial rate, and complex formulation, resulting in high costs. This study focused on determining the optimal graphene oxide (GO) and zinc oxide (ZnO) contents in an epoxy coating with higher anti-corrosive properties and the lowest cost. A range of GO mass was synthesized with a constant mass of ZnO, epoxy, and a hardener to find the optimal GO content, which was then applied to a range of ZnO masses. The composites were applied on carbon steel plates by the airless spray method to a thickness between 50 and 90 µm, adhering to ASTM standards. The test has indicated an optimum mass ratio of 1:10 for GO: ZnO. The electrochemical behavior of the coated plates was measured with electrochemical impedance spectroscopy/Tafel tests. The results confirmed the optimum combination with a corrosion rate of 2.19 × 10−5 mm/y and a polarization resistance of 21.498 mΩ controlling the degree of oxidation. Incorporating nanoparticles into the epoxy coating significantly increased barrier properties and enhanced corrosion resistance. This optimized GO-ZnO epoxy composite is a promising solution with enhanced durability and reduced cost as a protective coating in corrosive environments for industrial applications.