Corrosion behavior of HA containing ceramic coated magnesium alloy in Hank's solution

As a novel alternative biodegradable metal, magnesium possesses great potential and feasibility for bone fracture fixation due to its suitable mechanical properties, high degradability and biocompatibility. However, poor corrosion resistance in physiological fluids restricts their practical applications. In this study, HA contained coating on AZ31 Mg alloy substrate is prepared by MAO technique under various treatment times. The effect of treatment time on microstructure, composition, mechanical and corrosion properties is systematically investigated. The results indicate that MAO treatment is an effective route to improve the corrosion resistance. The enhanced corrosion is attributed to the barrier effect of the coatings. The failure mechanism of the MAO samples in Hank's solution is studied by long time immersion. A model for corrosion mechanism and corrosion process of the MAO coating on AZ31 Mg alloy in Hank's solution is proposed.