Preparation of a nano-sized α-Al2O3 powder from a supersaturated sodium aluminate solution

Nano-sized α-Al2O3 particles with an average size of 30–40 nm were prepared successfully from supersaturated sodium aluminate solution with liquid-attached aluminum hydroxide and nano-sized α-Al2O3 as seeds as well as a reasonable amount of PEG20000 as surfactant. The powders were characterized by differential scanning calorimetry (DSC)/thermogravimetry (TG), scanning electron microscopy (SEM) and X-ray diffraction (XRD). It was found that liquid-attached Al(OH)3 and nano-sized α-Al2O3 seeds can accelerate the precipitating process and reduce the α-Al2O3 particles size.