Effects of strontium substitution on the structural distortion of hydroxyapatite by rietveld refinement and Raman Spectroscopy

The strontium (Sr) substitution plays critical roles in physical-chemical-biological properties of hydroxyapatite (HA) bioceramics due to the structural distortion induced by doping. Herein, the effects of Sr substitution on the structural distortion of HA were investigated systematically by Rietveld refinement and Raman spectroscopy. We compared the occupation possibility of Sr in the lattice and pointed out its preferred occupancy. The effects of doping on lattice parameters, bond length, bond angle and crystallite size were also studied. The evidence, that doping will give rise to the distorted structure, has been shown. In addition, the PO43-, Ca-PO4 and OH- vibrations were further studied to verify the structural evolution and distortion. This work may be helpful in further studying on the structure-property relationship of Sr substitution HA.