Solution combustion method for synthesis of nanostructured hydroxyapatite, fluorapatite and chlorapatite

•We report a synthesis of HA, Fap and Clap vio a modified solution combustion method. The nucleation of β-TCP was inhibited in the abundant-calcium system (Ca/P=2.3>>1.67) in this study. F− brushed into the structure of HA and replace the position of OH− is easier than that of Cl−. Hydroxyapatite (HAP), fluorapatite (Fap) and chlorapatite (Clap) were prepared by solution combustion method with further annealing at 800°C. The characterization and structural features of the synthesized powders were evaluated by the powder X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM) and transmission electron microscopy (TEM) techniques. Characterization results from XRD and Rietveld analysis revealed that OH− in the HAP lattice were gradually substituted with the increase of F− and Cl− content and totally substituted at the molar concentration of 0.28 and 0.6, respectively. The results from FI-IR have also confirmed the incorporation of substituted anions in the apatite structure.