Bio-inspired graphene-based coatings on Mg alloy surfaces and their integrations of anti-corrosive/wearable performances.

Abstract Mg and its alloys generally exhibit the poor corrosion and wear resistances, which greatly limits their industrial applications. Inspired from an ordered layered structure within natural nacre, the homogeneous reduced graphene oxide/poly (vinyl alcohol) (RGO/PVA) coating is successfully fabricated on Mg alloy surface in the current study, through a facile spin-assisted layer-by-layer assembly (SA-LBL) technology. The hybrid hydrogen/covalent bond networks form between PVA chains and RGO sheets, resulting in a compact lamellar "bricks-and-mortar" structure. The microstructure of hybrid coating is strongly influenced by the cross-linking effect of PVA molecule, whose suitable content is beneficial to generating the densely stacked lamellar coating with excellent binding strength and reduced intrinsic defects, which can significantly improve its corrosion resistance. And the water molecules can hardly diffuse into the hybrid coating, leading to a long-term stability of samples in aqueous solution, ethanol and N, N-dimethylformamide. Besides, the high hardness and good lubricant effect of RGO sheets confer the hybrid coatings outstanding wear-resistant properties. Therefore, the bio-inspired RGO coating with a certain amount of PVA allows it to have a superior barrier effect and maintain the lubrication, which can provide an integrated protection for the corrosion and wear behaviors of Mg alloy. Graphical abstract Image [ABSTRACT FROM AUTHOR]