Thermal and ultrasonic influence in the formation of nanometer scale hydroxyapatite bio-ceramic

Abstract

GJE Poinern1, R Brundavanam1, X Thi Le1, S Djordjevic1, M Prokic2, D Fawcett1 1Murdoch Applied Nanotechnology Research Group, Department of Physics, Energy Studies and Nanotechnology, School of Engineering and Energy, Murdoch University, Murdoch, Western Australia, Australia; 2MP Inter Consulting, Le Locle, Switzerland Abstract: Hydroxyapatite (HAP) is a widely used biocompatible ceramic in many biomedical applications and devices. Currently nanometer-scale forms of HAP are being intensely investigated due to their close similarity to the inorganic mineral component of the natural bone matrix. In this study nano-HAP was prepared via a wet precipitation method using Ca(NO3)2 and KH2PO4 as the main reactants and NH4OH as the precipitator under ultrasonic irradiation. The Ca/P ratio was set at 1.67 and the pH was maintained at 9 during the synthesis process. The influence of the thermal treatment was investigated by using two thermal treatment processes to produce ultrafine nano-HAP powders. In the first heat treatment, a conventional radiant tube furnace was used to produce nano-particles with an average size of approximately 30 nm in diameter, while the second thermal treatment used a microwave-based technique to produce particles with an average diameter of 36 nm. The crystalline structure and morphology of all nanoparticle powders produced were investigated using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR). Both thermal techniques effectively produced ultrafine powders with similar crystalline structure, morphology and particle sizes. Keywords: nano-hydroxyapatite, chemical synthesis, ultrasonic irradiation, microwave irradiation