2003 Volume 10 Issue 306 Pages 316-321
Calcium phosphate films were deposited on stainless steel plate under various pH conditions of electrolytic solution of CaHPO4·2H2O by electrochemical procedure at room temperature. The pH at electrolyte dissolution was adjusted by nitric acid and the subsequent pH was adjusted by ammonium hydroxide. Calcium-deficient hydroxyapatite film a-DAp was deposited with pH 0.96 at the electrolyte dissolution and with pH 5.82 at the electrolysis initiation. The pH of the electrolytic solution was nearly constant from start to about 200 min and gradually decreased to about 3 after 400 min. The a-DAp had a feature of broccoli-like mass of which crystallinity was very low and the molar ratio Ca/P of 0.98. The low molar ratio was explained by substitution of H+ for Ca2+ during long time electrolysis in the bath of pH about 3.
