Four hydroxyapatite samples were synthesized by mean of different precipitation methods from aqueous solutions The reactants used for hydroxyapatite precipitation were: CaCl{sub}2-(NH{sub}4){sub}2HPO{sub}4, Ca(NO{sub}3){sub}2-(NH{sub}4){sub}2HPO{sub}4 and CaCl{sub}2-K{sub}2HPO{sub}4. The effects of varying synthesis conditions on stoichiometry and morphology of the obtained products were studied both for precipitated and dried HA powder and for burned at 1150°C powder. By chemical analysis, complexometric titration for Ca and gravimetry for P, was determined the stoichiometry of the products, or Ca/P molar ratio. The values varying between 1.5 and 1,67 were obtained. X-ray diffraction (XRD), IR-spectroscopy (IR) and Scanning electron microscopy (SEM) investigated the structure of the dried precipitates and the structural evolution upon the thermal treatment. Both, the IR spectra and XRD patterns indicate a high percentage of HA in all four samples. The crystallinity of the products increases upon thermal treatment for three hours at 1050°Cand 1200°C. SEM micrographs for one of the obtained HA showed that particles in the submicrometric size range were obtained.
展开▼
