Effect of high-energy ball milling on the formation and microstructural features of carbonated chlorapatite nanopowders

Carbonated chlorapatite nanopowders (n-CCAp) were synthesized by mechanochemical process from calcite (CaCO3), phosphorus pentoxide (P2O5), and calcium chloride (CaCl2) as raw materials. Results demonstrated that the formation of n-CCAp was influenced strongly by the milling time. At the beginning of milling (up to 15 min), CaCO3 and CaCl2 were the dominant phases, while P2O5 disappeared entirely due to its very high deliquescent nature. With increasing the milling time to 600 min, the progressive mechanochemical reaction was completed which resulted in the formation of nanostructured carbonated chlorapatite. According to the X-ray diffraction data, crystallite size of the product decreased from 24±1 to 21±2 nm when the milling time increased from 180 to 600 min, respectively. Microscopic observations illustrated that the final product had a cluster-like structure which was composed of polygonal particles with an average particle size of approximately 15±10 nm. To our knowledge, this is the first report of the production of pure n-CCAp; the synthesis reported here can be a promising candidate for use in biomedical applications. Structure and morphology evolution of product are reported here and have been studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM).