Role of material processing on the thermal stability and sinterability of nanocrystalline hydroxyapatite

Hydroxyapatite (HA) resembles natural bone mineral in its major composition and is widely applied for various biomedical applications in different forms. Wet chemical precipitation is an economic and simple route to synthesize HA. But the thermal stability and other related properties of synthesized HA depend on various factors. Here we demonstrate that when ultrasonication is coupled with synthesis and specimen is dried via sublimation (freeze drying) instead of the conventional hot air drying the thermal stability, densification and sinterability are improved.

Graphical abstractUltrasonic irradiation and freeze drying assisted wet precipitation method are found to offer HA with reduced particle size, low crystallinity and less agglomeration. Sintering of this HA exhibited high crystallinity, enhanced sinterability and thermal stability (up to 1100 °C) than the HA obtained by the conventional route.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Ultrasonic irradiation and freeze drying play significant role in HA synthesis. ► Synthesized HA displayed enhanced thermal stability. ► HA with high sinterability is achieved.