Strontium doped hydroxyapatite film formed by micro-arc oxidation

A porous strontium-doped hydroxyapatite (Sr-HA) film was prepared on titanium substrates by an electrochemical oxidation method, i.e. micro-arc oxidation (MAO). The reaction was processed using a pulse power supply with titanium substrate acted as the anode in electrolytic solution containing calcium acetate, strontium acetate and β-glycerol phosphate disodium salt pentahydrate (β-GP). The thickness, phase, composition and morphology of the coatings were investigated with X-ray diffraction (XRD), electron probe microanalysis (EPMA) and scanning electron microscopy (SEM) with energy dispersive X-ray spectrometer (EDS). The thickness of the film was about 20 µm with the porous and uneven surfaces. XRD showed that the film was mainly made up of hydroxyapatite doped with strontium and the (Sr/(Sr + Ca) ratios ranged from 0–100%, which could be expressed as the general formula of Ca10 − XSrX(PO4)6(OH)2, 0 ≤ X ≤ 10). Such films are expected to have significant medical applications as dental implants and artificial bone joints.