Preparation and Characterization of Hydroxyapatite/Alumina Nanocomposites by High-Energy Vibratory Ball Milling

Hydroxyapatite/alpha-alumina composites were prepared by means of high-energy vibratory ball milling. The effect of the addition of alumina, from 5 to 25 wt%, was investigated. x-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) results indicated that hydroxyapatite and alumina were the major phases after mechanical milling and only small peak shifts were observed. Transmission electron microscope (TEM) photomicrographs revealed that the powder obtained after mechanical milling was composed of nanoparticles in the size of similar to 40 nm. After 3h of air sintering at 1000-1200 degrees C, beta-tricalcium phosphate and alumina phases were found. The additional calcium aluminum phosphate phase might be formed during the sintering process at 1200 degrees C. The mechanical properties (compressive strength and Rockwell hardness) of the hydroxyapatite/alumina composites were improved with sintering temperatures and concentrations of alumina and the maximum value was found with 15 wt % alumina.