Low Temperature Synthesis of Ultrafine Al<sub>2</sub>TiO<sub>5</sub> Powders by Hydrolytic Sol-Gel Method
Abstract
Aluminum titanate (AT) ultrafine powder with high productivity ratio was prepared via hydrolytic sol-gel (HSG) method at 1250 °C, using aluminum nitrate (Al (NO 3 ) 3 ·9H 2 O) and titanium tetrachloride (TiCl 4 ) as precursors, ethanol as solvent through solvothermal treatment process. Water required for hydrolysis reaction was supplied by the crystal water of aluminum nitrate itself. The effect of process parameters including filling ratio, solvothermal temperature and soaking time on the synthesis of AT powder was investigated by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The cause of low temperature synthesis of AT was investigated. The result showed that excessive or insufficient filling ratio, too high or low solvothermal temperature, too long soaking time was not beneficial for the preparation of AT. The optimized ultrafine AT powder appeared at the decomposition temperature of 1250 °C with average particle size less than 1μm at a relatively high productivity ratio of 98 % with filling ratios of 60 %, solvothermal temperatures of 130 °C and soaking time of 30 min. The refinement of particles in the AT xerogel through solvothermal treatment process, and increasing reactivity of precursor, plays the key role in the low temperature synthesis of AT.