Graphene oxide-chitosan-silver composite coating on Cu-Ni alloy with enhanced anticorrosive and antibacterial properties suitable for marine applications

We present a novel ternary composite coating consisting of graphene oxide (G0)-chitosan -silver on Cu-Ni Alloy with enhanced anticorrosive and antibacterial properties, produced using inexpensive and industrially scalable electrophoretic deposition (EPD) technique. Electrochemical studies showed a corrosion protection efficiency of similar to 99 % and a two order decrease in corrosion current density, with an optimum GO concentration of 0.025 wt% (0.5 g/l of chitosan and 1 mM silver nitrate). The results indicate that the GO retards the diffusion of corrosive ions to the substrate by increasing the detour path and minimizes the electron transport between the electrolyte and metal specimen while chitosan prevents the galvanic coupling of GO with metal surface. The amide linkage between the GO and chitosan matrix gave a good mechanical interlocking, with a crack free compact film. AFM images of composite film surface showed a wrinkled morphology, with an enhanced surface roughness of 56 +/- 6 nm. Microbiological analysis revealed an excellent antibacterial activity of the ternary composite, which offer promising applications in marine environment.