Preparation and Characterization of Microcrystalline Hydroxyapatite Using Sol Gel Method

Hydroxyapatite ceramics have been recognized as substitute materials for bone and teeth in orthopaedic and dentistry field due to their chemical and biological similarity to human hard tissue. On implantation, the bioactive materials induce specific tissue response which results in the formation of a bonding interface between the implant and the natural bone tissue. Calcium phosphate is used as biomaterials such as synthetic bone graft, drug carrier and coating on metal prosthesis (in hip endoprosthesis and dental implants). Sol Gel technique has been developed and employed to prepare various materials because it has main advantage of easy control of chemical composition and low temperature synthesis that are very important for thin film formation. In this work, microcrystalline hydroxyapatite powder was synthesized from calcium acetate and tri ethyl phosphate in water and ethanol medium. The hydrolysis rate of tri ethyl phosphate in water and alcoholic medium was examined. The pH and gelation time of the batch containing with and without water was examined. The effect of calcinations on powder properties was studied. The XRD analysis was used to examine the phase transformation of hydroxyapatite at different temperature. At particular temperature calcium carbonate was observed and upon acid treatment the calcium carbonate peak at 29.399o was minimized and a stoichiometric hydroxyapatite was examined. The functional group change of hydroxyapatite at different temperature was observed by FT- IR spectroscopy. The morphological feature of the raw and sintered samples was examined. The synthesized powder was characterized through FT-IR, XRD and SEM analysis.