Facile synthesis of monodisperse α-alumina nanoparticles via an isolation-medium-assisted calcination method

Monodisperse and spherical α-alumina nanoparticles with a narrow size distribution in range of 11–18 nm have been prepared via the simple chemical precipitation and a new heat-treatment method, namely isolation-medium-assisted calcination. As-prepared α-alumina nanoparticles were characterized by means of X-ray diffraction analyses (XRD), thermogravimetry and differential thermal analyzer (TG–DTA), Fourier transform infrared spectroscopy, and field emission transmission electron microscope (TEM). XRD results confirm that the α-alumina in corundum structure is obtained by heating at 1,000 °C for 3 h. And TEM observations reveal the additional isolation medium surrounded α-alumina precursor forms the lamella, which effectively reduces direct contacts between precursor particles and prevents the agglomerating of the aluminum hydroxides during drying process and then the sintering and growth of the alumina nanoparticles are avoided during calcination. The highly uniform and monodisperse α-alumina nanoparticles are obtained.