Research on the formation of nano-size hydroxyapatite in glass based bone cement

In this experiment glass based bone cement (GBC) was synthesized by mixing CaO-SiO_2-P_2O_5 based glass powder with ammonium phosphate liquid. Phase compositions, chemical compositions and microstructure of the final products of GBC were measured and observed using X-ray diffraction(XRD), Fourier transform infrared spectroscopy(FTIR) and scanning electronic microscope (SEM) respectively. The experiment shows that with a longer immersion time in simulated body fluid (SBF) the glass phase in GBC gradually changed to hydroxyapatite (HAP). It also indicates that the crystal formed in GBC belongs to a bone-like hydroxya-canbonate apatite crystallite with the end plane granularity 30～50nm. Mechanical testing results show that the compressive strength of GBC increases with the proceeding of immersion in SBF, reaching 80MPa after 30days. It was evident that GBC was a desirable biomedical material for the repairing of bone defects with an excellent biocompability and high mechanical strength.