Hydroxyapatite formation on oxide films containing Ca and P by hydrothermal treatment

Oxide films were formed on titanium by means of microarc oxidation (MAO) using a direct current power supply. The oxide films containing Ca and P were obtained in an electrolyte containing beta-glycerophosphate sodium salt pentahydrate (P-GP) and calcium acetate (CA). The surfaces of the oxide films were rough and porous, and the concentration of Ca and P were 7.3 mol% and 6.4 mol%, respectively, when MAO was performed in an electrolyte containing 0.04 M beta-GP and 0.10 M CA at 200 A/m(2) current density and 430 V final voltage. The oxide film consists of anatase, rutile and an amorphous phase. After hydrothermal treatment at 190 degrees C, the hydroxyapatite crystals were precipitated on the oxide film surfaces. The amount of hydroxyapatite crystals increased by increasing the hydrothermal treatment time and the Ca/P ratio in the oxide film. (c) 2005 Elsevier Ltd and Techna Group S.r.l. All rights reserved.