Corrosion protection coating of three-dimensional metal structure by electrophoretic deposition of graphene oxide

Corrosion protection of metals is of great importance in many applications. Electrophoretic deposition (EPD) is one of the most effective techniques to produce anticorrosive graphene coatings on metals. However, EPD coating on complex shaped surfaces, such as three-dimensional (3D) structures, has rarely been reported, despite its importance in practical applications of metal anti-corrosion. In this study, we prepared three kinds of graphene oxide (GO) nanosheets with large, medium, and small lateral sizes through simple dispersion methods, such as stirring, sonication, and homogenizer, respectively, and coated them on the surface of two-dimensional (2D) steel (Fe) plates and 3D Fe rods by the cathodic EPD process. As the lateral size of the coated GO sheets increased, a smoother and thicker coating layer was formed on the Fe plate, which resulted in better corrosion resistance. In addition, novel EPD equipment with multi-electrodes has been developed to coat GO sheets onto 3D metal structures. The GOs were successfully coated on 3D Fe rod using the EPD equipment with multiple electrodes, leading to improvement of the corrosion resistance while maintaining the high electrical conductivity. This approach provides a viable and scalable route for using graphene oxide coatings to protect metal surfaces from corrosion.