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Poor corrosion and wear resistances of Mg alloys have severely restricted their extensive applications. Here we report a comparative study of bioinspired graphene oxide(GO)/reduced graphene oxide (rGO)-polyvinyl alcohol (PVA) composite films with nacre-like architectures on Mg alloys, via a facile reduction process. GO-PVA film remarkably deteriorates the corrosion resistance of Mg alloy, with an increased corrosion rate of 3.657 × 10−5 from 2.038 × 10−5 A/cm2, due to its loose microstructure and typical cathodic reaction. In contrast, the removal of oxygen-containing groups by chemical reduction leads to a recovery of conjugated structure and reduces the intrinsic capillaries, and the corrosion rate of rGO-PVA film is 18 times lower than that of GO-PVA film, through hindering the galvanic corrosion and weakening the cathodic reaction. Additionally, the wear rate of Mg alloys protected by GO/rGO-PVA films remarkably decreases by 98.6% and 98.2%, respectively. The chemical reduction effectively decreases the cluster-stacked structure on the surface of the GO-PVA film and restricts its exfoliation behavior, which promotes the puckering effect and results in a slightly enhanced wear behavior of the rGO-PVA film. The current study demonstrates a potential prospect of the bioinspired graphene-based film, which is beneficial to achieving the integrated anti-corrosive/wearable performances of metallic materials. Image 1 [ABSTRACT FROM AUTHOR]

The poor corrosion and wear resistances hinder the industrial applications of magnesium and its alloys. In this paper, a new graphene oxide (GO) coating is fabricated on the surface of extruded Mg-Zn-Ca alloy, via the silane coupling agent. The GO coating has fully covered the Mg substrate through the chemical reactions, and formed an overlapped multilayer structure by interlocked effects. Electrochemical measurements indicate that the anti-corrosion performance can be remarkably improved by silane/GO coating, because the stable covalent bonds within the coating effectively restrict the penetration of electrolyte into the Mg surface, representing an excellent corrosion barrier effect. The GO coating drastically promotes the wear resistance, due to the superior bonding between the Mg substrate and GO sheets with high hardness and good lubricant effect. [ABSTRACT FROM AUTHOR]