Fabrication and characterization of highly crystalline Hydroxyapatite used for bone joining, replacement and reconstruction

This work focuses on studying the effect of sintering temperature ,pressing pressure and sintering time (soaking time) on phases generated, porosity and fracture strength of sintered HA powder compact at a range of (800-1200) ̊C , (38.378-153.513)Mpa and (1-5)hr respectively, and evaluation of sintered HA powder compact in synthetic body fluids(SBF), to indicate the biological bioactivity . Both Ca/P ratio and crystallinity were increased after calcination, where the Ca/P ratio raised from 1.7 to 1.9 and the height of Hydroxyapatite peak intensity was also increased .An important Secondary phases were appeared especially the Ca2P2O7 phase. X-ray diffraction patterns and electrical microscopic pictures of polished surfaces of the Hydroxyapatite compact after sintering had revealed the process of densification and crystallization of Hydroxyapatite . The increase of temperature leads to grain growth ,while surface cracking and other defects became lower i.e. porosity and surface voids .The maximum content of Hydroxyapatite and Ca2P2O7 were found seen at pressing pressure of (76.756)Mpa. Fracture strength was reached its maximum amount at(1200) oC, (115.134)Mpa and after (3)hrs of soaking time.Radiographic X-ray pictures ,XRD test and electron microscopy photographs of sintered samples before and after incubation in vitro shows an alteration in sample morphology i.e. (surface erosion) and a decrease in sample diameter and the utilization of β-Ca2P2O7 indicates the chemical reactivity of prepared Hydroxyapatite powder compact .