Evaluation of calcium phosphate coating on biodegradable Mg–Al–Zn–Ca alloy formed under ordinary conditions on temperature and pressure

Abstract

Octacalcium phosphate (OCP) coating was formed on the surface of Mg–Al–Zn–Ca alloy (AZX612) by anodically oxidized and subsequently immersed in a supersaturated aqueous solution containing phosphate and calcium ion under ordinary temperature and pressure. The formed OCP layer consisted of both the inner layer of the fine crystallites and the outer layer of the large crystallites, and the inner layer remained on the alloy even after the ultrasonication process. In simulated body fluid, AZX612 treated with both anodic oxidization and subsequent OCP coating process showed higher corrosion resistance than those treated with only anodic oxidization.