Synthesis and characterization of hydroxyapatite obtained from different organic precursors by sol-gel method

The synthesis of four types of hydroxyapatite synthesized from calcium chloride and four different organic phosphites is presented. The method of synthesis chosen is the sol-gel route, which has a number of advantages compared to other methods, like the intimate contact between reactants and the milder synthesis conditions. The samples were thermally treated, the TG/DTG/DTA curves being obtained at four heating rates, namely: 7, 10, 12 and 15 A degrees C min(-1). The samples were characterized before and after the thermal treatment using FT-IR analysis. The FT-IR spectra certified that the formed compounds represent hydroxyapatite. Based on the information from the TG curves and IR spectra interpretation, a reaction mechanism was proposed.