Solution Treatment as Pretreatment for Corrosion Resistance and Cytocompatibility of Micro-Arc Oxidation Coating on Biodegradable Mg Alloy

The effects of solution treatment on the corrosion resistance and cytocompatibility of micro-arc oxidation (MAO) coating on biodegradable Mg-2Zn-1Gd-0.5Zr alloy were studied in this work. Microstructural characterization, coating adhesion, electrochemical, immersion and cytocompatibility tests were carried out. The results demonstrated that the MAO coating was much more uniform after solution treatment with coating adhesion enhanced by about 30% compared with the as-extruded + MAO coated. Moreover, the corrosion resistance of the solution treated + MAO coated samples was respectively improved by more than 20% and twice, compared with as-extruded + MAO coated and as-extruded samples. In addition, solution treatment further improved the cell viability of the MAO coating of the alloy with the RGR exceeding 90% during the entire culture period with MG63 cells. Consequently, solution treatment is recommended as a preferred pretreatment for improving the corrosion resistance and cytocompatibity of MAO-coated Mg alloys.