Microwave assisted deposition of hydroxyapatite coating on a magnesium alloy with enhanced corrosion resistance

• A thick and uniform hydroxyapatite coating was deposited on Mg alloy by microwave.
• Rod-like hydroxyapatite crystals were formed under microwave irradiation.
• The obtained hydroxyapatite coating offered high corrosion resistance for Mg alloy.
• The thickness of hydroxyapatite coating derived by microwave heating was ∼9.9 μm.

In this work, a thick, dense and uniform microstructural hydroxyapatite coating was deposited on a magnesium alloy in an aqueous solution under microwave irradiation at 100 °C in a short time of 10 min. The results showed that the high driving force of interfacial growth under microwave irradiation greatly promoted the growth of hydroxyapatite nuclei into rod-like crystals, and the thickness of obtained hydroxyapatite coating was ∼9.9 μm, larger than that of ∼6.3 μm derived by water-bath heating. The coating derived by microwave heating offered preferable corrosion resistance for the magnesium alloy compared with the coating derived by water-bath heating. The corrosion current density of the coated magnesium alloy was reduced by 100-fold as compared to the naked magnesium alloy.