Alumina phase transformation behavior on titania-doped nano α-Al2O3 powder by a solid liquid process was investigated under various conditions, such as different solvent concentrations and calcining temperatures. Three batches of the precursor powders were calcined at three different temperatures of 600 oC, 750 oC and 900 oC for 5 h and a final product of titania-doped nano α-Al2O3 powder was obtained. The product has been identified by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The XRD results show that the alumina phases of the powders were determined to be γ-Al2O3 and α-Al2O3. The optimum calcination temperature of the precursor powder for crystallization of nano α-Al2O3 was found to be 900 oC for 5 h. A higher concentration of solvent used for the sample preparation leads to the formation of a uniform and very smooth particle morphology, and smaller particle grains. The TEM images indicate that the average size of α-Al2O3 grains was ≤ 50 nm and larger grains of TiO2 with 50-250 nm sizes.

Keywords: Alumina, Phase transformation, Titania, Doping, Calcining temperature, Solvent concentration