Preparation and properties of bioactive coralline hydroxyapatite/fluoroapatite-zirconia composites

Hydroxyapatite/fluoroapatite-zirconia composites were prepared by two different methods using Indian coast corals. In the "low temperature method" 10 mol.% zirconia is mixed with the coral and a exchange reaction with di-ammonium phosphate is carried out to form apatite at 250/spl deg/C under pressure. The coralline derived hydroxyapatite/fluoroapatite by the above method is reacted with zirconia at 900/spl deg/C in the "high temperature method". The X-ray powder diffraction, infrared spectroscopy and thermal analysis were employed to characterise the formation of the composites. In-vitro solubility tests in the phosphate buffer solution of pH 7.2, indicated the stability of the composites. The low temperature method of preparation seems to be advantages due to better in-vitro stability and absence of impurity phases.