FTIR and XRD investigations on the thermal stability of hydroxyapatite during hot pressing and pressureless sintering processes

Performance of hydroxyapatite material in a living body depends on a number of factors. Stability of hydroxyapatite structure, which is influenced by both, preparation conditions of the starting precursor powders and fabrication method of the implant materials, is an important one. Inappropriate preparation conditions of synthesis, calcination of powder and sintering of formed samples result in dehydroxylation and even in decomposition of HAp which lead to the change in the physicochemical properties of implants. In the work samples of hydroxyapatite ceramics have been obtained by two methods, i.e. by hot pressing and by pressureless sintering in the temperature range of 1150–1300 °C. The materials prepared have been studied using FTIR and XRD in order to identify the dehydroxylation processes and the possible hydroxyapatite decomposition during thermal treatment. The usefulness of both methods in identification of thermal stability of hydroxyapatite was confirmed.