Microwave assisted deposition of strontium doped hydroxyapatite coating on AZ31 magnesium alloy with enhanced mineralization ability and corrosion resistance

Abstract Strontium has been suggested to have beneficial effects on bone remolding when incorporated at a suitable dose in apatite. In this work, strontium doped hydroxyapatite coating was prepared on magnesium (Mg) alloy substrates via microwave assisted deposition method for the purpose of improving the corrosion resistance and bioactivity of the substrates. A homogeneous and crack-free strontium doped hydroxyapatite (SrHA) coating with a special dual-layer structure was successfully fabricated on Mg alloy substrates in a short time of 10 min under microwave irradiation. Immersion tests in simulated body fluid (SBF) revealed that SrHA coatings could provide protection for Mg alloys in the initial stage and simultaneously induce new apatite precipitation to form a dense layer on the coating surface, suggesting that the SrHA coatings could accelerate the apatite precipitation and thus improve the bioactivity of Mg alloy substrates. The long-term immersion and electrochemical tests revealed that the deposited apatite layer could markedly improve the corrosion resistance of the coated samples over the immersion period of 32 days.