Preparation and Characterization of Al_2O_3/TiO_2 Hyperthermophilic Nanometer Powders by Precipitation Process

Al_2O_3/TiO_2 nanometer powders are prepared by a precipitation method from TiCl_4 and Al_2(SO_4)_3. The phase transition and the growth procedure of the nano material grain size are analyzed.The results shows the nano- meter TiO_2 powder composited with Al_2O_3 resists high temperature remarkably. The crystal growth of anatase is suppressed and the phase transition from anatase-type to rutile-type structure is shifted to a high temperature. When the calcining temperature of nanometer Al_2O_3/TiO_2 is 950℃, it exhibites small crystallite sizes of 20 nm and the content of anatase is 77%. The temperature of transition from anatase-type to rutile-type structure is at high temperature of 950～1100℃. UV-Vis absorption suggests that the optical absorption properties of Al_2O_3/TiO_2 are enhanced.