Effects of synthesis conditions on the morphology of hydroxyapatite nanoparticles produced by wet chemical process

Nanoparticles of hydroxyapatite (HAP) were synthesized by means of wet chemical precipitation method, under atmospheric pressure. HAP powders with various morphologies, such as sphere-, rod-, needle-, wire- and bamboo-leaf-like, were obtained by controlling the synthesis conditions. It was found that the solvent systems, dispersant species and drying methods had effects on the particle size and dispersibility. The initial pH values and reaction temperatures both played important roles in the morphology of HAP, as well as the phase formation and degree of crystallinity. The possible influence process of initial pH values and reaction temperatures was discussed in details. The crystal morphology and particle size were analyzed by transmission electron microscopy (TEM) and scanning electron microscope (SEM), and the compositions and chemical structures were identified by X-ray diffractions (XRD) and Fourier transform infrared spectroscopy (FTIR).