Rapid synthesis of hydroxyapatite nanopowders by a microwave-assisted combustion method

Nano bioactive hydroxyapatite (Ca-10(PO4)(6)(OH)(2), HAp) ceramic powders have been synthesized by a microwave-assisted combustion method. The powders were synthesized using calcium nitrate tetrahydrate (as the source of calcium) and sodium phosphate dibasic anhydrous (as the source of phosphate ions). Glycine, citric acid and urea were used as fuesl. The influence of the fuel type on the structure and morphology of the samples was studied. Results by X-ray diffraction and Fourier-transform infrared spectroscopy showed the formation of hydroxyapatite as a major phase for all the samples. Using the Scherrer formula, the average crystallite size was found to be in the range of 10 to 28 nm. SEM-EDX results showed highly crystalline nano-powders with an elemental composition of Ca and P in the HAp phase. The morphology of the particles was dependent an the fuel type and changed from semi-spherical to elongated. Smaller particles were obtained with glycine as the fuel.