Structural characterization of silicon-substituted hydroxyapatite synthesized by a hydrothermal method

Silicon-substituted hydroxyapatite (Si-HA) was prepared successfully by hydrothermal method. The crystalline phase, microstructure, chemical composition, morphology and thermal stability of Si-HA were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). The results show that the substitution of the silicate groups for the phosphate groups causes some OH- loss to maintain the charge balance and changes the lattice parameters of HA. Furthermore, the substitution of the silicate groups restrains the growth of Si-HA crystal. DSC analysis shows that the small amount of silicon incorporates into HA lattice does not influence the thermal stability of HA.