VIBRATION SPECTROSCOPY STUDY OF PYROLYSED PRECURSORS FOR SINTERING CALCIUM PHOSPHATE BIO-CERAMICS

Diffuse reflectance infrared Fourier transform and Raman spectroscopy were used to investigate the structure of hydrolysed CaHPO4.2H2O (DCPD) processed to non-stoichiometric apatite to be used for preparing sintered calcium phosphate materials. The spectra of hydrolysed DCPD samples, obtained under differing experimental conditions, were analysed to check how the sintered phase composition correlated with the structure of the hydrolysed precursor. Addition of extra Ca2+ ions in the alkaline solution during the process of hydrolysing affected strongly the degree of disorder in the structure of the hydrolysed materials, thus increasing the relative amount of hydroxyapatite in the final sintered product. The addition of F- ions to the synthesis mixture strengthened slightly the P-O bonds in the precursors and increased the content of hydroxyapatite phase in the sintered material. As a result, bi-phase ceramics of highest content of hydroxyapatite could be produced using both fluorine additives and calcium compensators in the synthesis suspension. 15 refs.