MAO-DCPD composite coating on Mg alloy for degradable implant applications

Magnesium (Mg) is a promising metallic material for use as degradable orthopedic implants. The density and Young's modulus of Mg are close to those of human bone, and it is non-toxic and degradable in body fluids. However, the realization of Mg as an implant material is hampered by its high corrosion rate. The present article aims at improving the corrosion resistance and bioactivity of a Mg alloy AZ80 via surface treatment. AZ80 was coated with a composite coating consisting of an oxide layer formed by micro-arc oxidation (MAO) and a top layer of dicalcium phosphate dihydrate (DCPD, CaHPO4·2H2O) fabricated by electrodeposition. The corrosion behavior and apatite-forming ability in simulated body fluids (SBFs) were studied using hydrogen evolution measurements and SEM. The results show that the MAO-DCPD composite coating significantly reduces the corrosion rate of AZ80 and at the same time enhances the deposition of apatite on the coating.

Hydrogen evolution rate and evolution of pH during immersing in SBF.Figure optionsDownload as PowerPoint slideResearch Highlights
► A composite coating of MgO/DCPD was successfully fabricated on a Mg alloy.
► The composite coating significantly enhances the corrosion resistance in SBFs.
► The apatite-forming ability in SBFs is improved by the composite coating.