ABSTRACT
The thermal stabilities of a variety of hydroxyapatite (HAp), Ca10(PO4)6(OH)2, samples prepared by different wet-chemical methods have been studied. The results show that the thermal stability of a HAp is intrinsically dependent on its stoichiometry and the crystal structure. The stoichiometry and crystal structure are, in turn, related to both the precursor and the synthesis conditions. The optimum thermal stability up to 1370°C (in air with 50% relative humidity) was observed in the HAp samples prepared by a hydrothermal method and by the hydrolysis of brushite followed by proper ripening.
