Comparative study on effects of different coatings on biodegradable and wear properties of Mg-2Zn-1Gd-0.5Zr alloy

Coating is one of the effective methods to improve the corrosion resistance of the biodegradable Mg alloys. In this work, comparative study on the effects of micro-arc oxidation (MAO) coating, SrP coating and CaP coating on the biodegradable and wear properties of Mg-2Zn-1Gd-0.5Zr alloy were investigated. The results showed that the degradation deposition contained Gd on the surfaces of both MAO coating and SrP coating, which stabilized the coating, thereby increasing the degradation resistance of the alloy. The wear test showed that MAO coating and CaP coating exhibited good wear resistance. For a 5 N loading, the sliding distances of MAO coating, SrP coating and CaP coating were 2.24 m, 0.29 m and 9.00 m respectively, before the coatings were completely destroyed. This investigation revealed that the MAO coating exhibits the best degradation resistance and the CaP coating exhibits the best wear resistance.