In vitro degradation, wear property and biocompatibility of nano-Y2O3-containing micro-arc oxidation coating on ZK60 alloy

In order to further improve the degradation resistance and wear property of micro-arc oxidation (MAO) coating on magnesium alloys, nano-Y2O3 was added into the electrolyte to fabricate a nano-Y2O3-containing MAO coating. Microstructural characterization, wear test, electrochemical test, immersion test and cytotoxicity test were carried out. The results showed that there were mainly Ca8MgY(PO4)7 and Y2O3 particles in the MAO coating. Ca8MgY(PO4)7 could stabilize the coating and the nano-Y2O3 could seal the micro-pores. Therefore, both the degradation resistance and wear property of the coating were improved. The degradation rate decreased from 0.14 to 0.06 mm/a in Hank's solution. The volume loss decreased from 0.46 to 0.27 mm3 at the same slip distance. MAO coating exhibited good biocompatibility with the cell relative growth rate (RGR) value of more than 90%. The nano-Y2O3-containing MAO coating thus has a good promising biomedical application.