Vibration spectroscopy study of hydrolyzed precursors for sintering calcium phosphate bio-ceramics

Diffuse reflectance infrared Fourier transform and Raman spectroscopy is ap plied to investigate the structure of hydrolyzed CaHPO4 . 2H(2)O (DCPD) pro cessed to non-stoichiometric apatite to be used as starting material for pr eparing sintered calcium phosphate materials. The spectra of hydrolyzed DCP D samples, obtained under differing experimental conditions, are analyzed t o check how the sintered phase composition correlates with the structure of the hydrolyzed precursor. It is shown that the addition of extra Ca2+ ions in the alkaline solution during the process of hydrolyzing affects strongl y the degree of disorder in the structure of the hydrolyzed materials, thus increasing the relative amount of hydroxyapatite in the final sintered pro duct. The addition of F- ions to the synthesis mixture strengthens slightly the P-O bonds in the precursors and increases the content of hydroxyapatit e phase in the sintered material. As a result bi-phase ceramics of highest content of hydroxyapatite can be produced using both fluorine additives and calcium compensators in the synthesis suspension. (C) 2001 Kluwer Academic Publishers.