Characterization of single-crystal fluorapatite nanoparticles synthesized via mechanochemical method

The synthesis of nanostructured fluorapatite (FA; Ca(10)(PO(4))(G)F(2)) was explored from the starting materials of CaHPO(4), Ca(OH)(2), CaO, P(2)O(5) and CaF(2) via a mechanochemical process. In this research, the suitability of using the mechanochemical process to prepare a high crystalline phase of FA was studied. The characterization and structural features of the synthesized powders were evaluated using powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques. The results from the structural studies indicate that the maximum lattice disturbance in the apatite structure after the mechanochemical process was at the (0 0 2) plane. Furthermore, the maximum particle size was below the crystallite size after 60h of milling and subsequent thermal treatment at 600 degrees C for 1 h (heated up to 600 degrees C and kept for 1 h at this temperature). We determined that this method gives rise to the single-crystal FA with an average size in the range of 25 +/- 5 to 29 +/- 9 nm. The present findings suggest that the solid-state reaction and appropriate thermal process simultaneously lead to the formation of nanostructured FA with spheroidal shape. (C) 2011 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.