Influence of Aging Time of the Sol on the Synthesis of Hydroxyapatite Powders Using Ca(NO3)(2)center dot 4H(2)O and H3PO4 as Precursors

Abstract

In this paper, hydroxyapatite (Ca-5(PO4)(3)(OH)) was synthesized by sol-gel method. Calcium nitrate (Ca(NO3)(2) center dot 4H(2)O) and phosphoric acid (H3PO4) were used as calcium and phosphate precursors in methyl alcohol solvent. The influence of the aging time (24 h, 240 hours, 480 hours and 720 hours) of the sol on the crystal structure and stability of the CaP powders were evaluated. The effect of calcination temperature on composition of the HA phase were characterized by FTIR, XRD and SEM. These techniques confirmed the presence of the hydroxyapatite phase and CaO. The formation of CaO which was attributed to phosphorous volatilization The stability of the sol during long-term storage was also investigated, indicating potential use as bioactive coating for dentistry and orthopedic implants.