Physico-Chemical Characterization of Animal Bone-Derived Hydroxyapatite Sintered at Different Temperatures

This study describes the effect of sintering temperature on mechanical properties, microstructure, chemical functional groups, and in-vitro bioactivity of hydroxyapatite (HA) extracted from bovine (BHA), galline (GHA) and porcine (PHA) bone. The HA was subjected to various sintering temperatures of 800, 1000, and 1200 ℃. At 1200 ℃, galline bone produces HA with maximum mechanical hardness (70.73 ± 8.49 N), which is higher than bovine HA (25.33 ± 5.27 N), the most common natural HA source, and the other samples. In addition, the morphology and particle size variations of HA samples are observed by scanning electron microscope (SEM). The results show that the average grain sizes become significantly more extensive and compact as temperatures increased from 800 to 1200 ℃. In addition, the morphology of the HA-sintered body was also evaluated after soaking in simulated body fluid (SBF) for seven days to assess the bioactivity. It shows that a new apatite structure formed on all HA samples except GHA sintered at 1000 ℃ and PHA sintered at 1000 ℃ and 1200 ℃. Thus, the sintering temperature can significantly affect the microstructure, hardness, and bioactivity of HA-derived animal sources.