Comparative Research on the Synthesis of Aluminum Titanate Powders by Nonhydrolytic and Hydrolytic Sol-Gel Method

Aluminum titanate powder was synthesized by nonhydrolytic and hydrolytic sol-gel method, respectively. The sol-gel process, the phase transformation and the sintering properties of powders were studied by TG-DTA, XRD, FT-IR and SEM analysis. The results show that during the hydrolytic sol-gel process, the Al3+ ions mostly exist in the interspace of Ti-O-Ti network. As a result, only rutile and corundum are separated from the hydrolytic gel, the Al2TiO5 has to be synthesized at 1350 degrees C. Comparatively, the gel network is formed through the polymerization reaction of Al3+ and Ti4+ ions in nonhydrolytic sol-gel process, these ions occupy the similar position to build the gel network together. Therefore, the armorphous phase is directly crystallized at 750 degrees C as aluminum titanate. The particle size and specific surface area of Al2TiO5 powders prepared by hydrolytic sol-gel method are 1 - 2 mu m and 3.2 m(2)/g. It is dropped to 0.1 - 0.3 mu m under nonhydrolytic sol-gel method, while the specific surface area of the powders is 35 times of hydrolytic sol-gel sample. The bending strength of the sintered Al2TiO5 ceramic prepared by nonhydrolytic sol-gel method is 2.3 times of hydrolytic sol-gel sample, which is only 7.2MPa. It indicates that the properties of Al2TiO5 powders prepared by nonhydrolytic sol-gel method are better than that of hydrolytic sol-gel sample.