Corrosion Behavior and Biocompatibility of Graphene Oxide-Plasma Electrolytic Oxidation Coating on Magnesium Alloy

Due to its high deterioration rate in the physiological environment, the clinical application of magnesium (Mg) in bone repair has been restricted. Graphene oxide (GO)-plasma electrolytic oxidation (PEO) coatings were effectively applied to Mg alloy to enhance corrosion resistance and biocompatibility. The structure, biocompatibility, electrochemical characteristics, and long-term corrosion performance of composite coatings were studied in the present paper. The incorporation of GO to the PEO layer decreased wettability of all samples, resulting in hydrophobic behavior. The amount of GO incorporated in the PEO layer had a minor effect on the film thickness, but the pore size of the PEO coating decreased as the amount of GO increased. PEO/GO coatings have better corrosion resistance than counterpart PEO coatings and bare samples, according to electrochemical tests. The results also demonstrated that corrosion resistance increases significantly as GO concentration increases, owing to the fact that GO nanosheets in the coating operate as a barrier to the electrolyte diffusion route, preventing aggressive electrolytes from accessing the substrate. Because of dramatically decreased Mg ion release and changes in pH value in the culture medium, all of the PEO and PEO/GO coatings could improve MG63 cell attachment and differentiation compared to the bare Mg alloy sample. The as-prepared PEO/GO coating on Mg alloy is attractive for medical applications due to its satisfactory corrosion resistance and biocompatibility.