Enhanced corrosion resistance of hydroxyapatite/magnesium-phosphate-composite-coated AZ31 alloy co-deposited by electrodeposition method

Magnesium-phosphate-doped hydroxyapatite (HAMP, Mg3(PO4)2-Ca10(PO4)6(OH)2) and magnesium-hydrogen-phosphate-doped dicalcium-phosphate-dehydrate (DCPD-MHP, MgHPO4-CaHPO4) composite coatings were successfully electrodeposited onto an AZ31 alloy, and their corrosion behaviour was evaluated via electrochemical and in vitro degradation tests. In addition, the stability of the coatings was evaluated via these electrochemical tests. The results showed that the corrosion resistance and stability of the composite coatings were both significantly higher than those of single coatings; this greater resistance and stability resulted from the denser and more uniform structures of the composite coatings.