Titanium plates were treated in [Ti(O-2)EDTA](2-)-Ca(EDTA)(2-) mixed solutions and/or Ca(EDTA)(2-) solutions (where EDTA is ethylene diamine tetra acetic acid) at pH 9-13 and 150-250 degrees C for 0.5-12 h. The fi Im, about 50 mu m thick, a nd consisting of mixtures of CaTiO3 and TiO2 was formed in 0.01M [Ti(O-2)EDTA](2-)-0.01 M Ca(EDTA)(2-) mixed solution at pH 13 and 250 degrees C for 6 h. The film consisted of large icosahedral and hexagonal particles, of about 10 mu m diameter, and small aggregated particles, of about 1 mu m diameter. On the other hand, the film, about 20 mu m thick, consisted of hexagonal plate-like CaTiO3 particles, of about 1 Cim diameter, was formed in 0.01M Ca(EDTA)2- solution at pH 13 and 250 degrees C for 6 h. The thickness of both films increased with time, where the film formation rate in 0.01 M [Ti(O-2)E DTA](2-) -0.01 M Ca(E DTA)(2-) mixed solution was much faster. The CaTiO3 film formed on the surface of titanium promoted the precipitation of hydroxyapatite on the substrate by the hydrothermal reactions in Ca(EDTA)(2-)-PO43- mixed solutions.
