Characterization of Electrolytic Al[sub 2]O[sub 3]/CaP Composite Coatings on Pure Titanium

Electrolytic composite coatings of calcium phosphate (CaP) and were successfully deposited on titanium substrates in the mixed solution of and and subsequently in aqueous solution, respectively. After annealing at 400°C for 4 h in air, the coated specimens were evaluated by electrochemical polarization and immersion tests in Hank's solution, hardness test, scratch test, surface morphology observations, and X-ray diffraction analyses. The corrosion resistance, hardness, and adhesion strength of the CaP-coated film were improved, and the oxidation of Ti was also effectively retarded in air by the subsequent electrolytic deposition of Phase transformations of CaP-coated and -coated specimens were further identified in detail. The initial dissolution of hydroxyapatite (HA) with (002) preferred orientation and final reprecipitation of randomly oriented HA were found after immersion tests in Hank's solution.