F-substituted hydroxyapatites were synthesized by chemical precipitation method using Ca(CH3COO)2·H2O and KH2PO4 as reactants and KF·2H2O as fluorination agent. Fourier transform infrared spectrometer (FTIR), X-ray diffraction (XRD) and X-ray fluorescence spectrometer (XRF) were used to characterize samples. The results showed that the more fluorine was added the more OH ions replaced by F. Moreover, OH-F bond was formed between crystalline, and the bond was stronger than that of original OH-OH, so the grains of hydroxyapatite grew larger and the crystallinity increased as F content increased.

Keywords: Hydroxyapatite, Fluoride-substituted, OH-F bond, Crystallinity