Electro-brush plating Ni-Graphene oxide composite coating enhanced corrosion resistance of fluoride ion

Abstract

Ni-Graphene Oxide(GO) composite coating was prepared on Q235 steel plate by electro-brush plating technique to reduce the corrosion of fluoride ion. In this study, SEM, XRD and Raman tests were performed to analyze the morphologies and structures of the coatings, then electrochemical characterization was evaluated to determine the corrosion resistance. The results showed that GO provided more nucleation sites, and the surface of coatings looked more uniform and much denser because GO and Ni atoms were co-deposited on coating surface. The composite coating showed a better corrosion resistance than the pure nickel and there was an optimal addition amount of GO (Ni-GO/0.75 coating). In detail, the corrosion voltage increased from-0.61187 V to-0.52542 V, and the corrosion current correspondingly decreased from 26.6 μA•cm-2 to 6.8 μA•cm-2, correspondingly. The charge transfer resistance was also increased from 558.6 Ω to 1769.0 Ω. Moreover, the immersion testing demonstrated that the weight loss of Ni-GO/0.75 composite coating was only 22.2% of the pure nickel. In addition, XPS spectra indicated that the fluoride ions in the corrosive medium preferentially bonded with nickel atoms, preventing the medium from entering the active area. In conclusion, Ni-GO composite coating exhibited excellent corrosion resistance to fluoride ion due to the impermeability and high conductivity of GO.