Synthesis and characterization of sintered hydroxyapatite: a comparative study on the effect of preparation route

Hydroxyapatite (HAp) is prepared synthetically by three different routes—wet chemical coprecipitation, sol–gel, and solution combustion routes. Different characterizations of the powders obtained from different routes were done for comparative analysis. The as-prepared powders were calcined between 600 and 1300 °C and studied for phase stability using X-ray diffraction (XRD). The thermal analysis and Fourier transform infrared (FTIR) spectroscopy analysis were also studied. The calcined powders were observed for microstructural changes at different temperatures using field emission scanning electron microscope (FESEM). The powders were then pressed to form pellets for analyzing the different sintering behavior such as dilatometry, bulk density, and apparent porosity. The sintered pellets were also examined under FESEM. It was observed that the HAp obtained from coprecipitation route (HCop) achieved the highest bulk density as well as hardest among all. Bioactivity test was also done for HCop samples for 7, 14, 21, and 28 days and observed under FESEM.