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

Abstract

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℃.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℃ as aluminum titanate.The particle size and specific surface area of Al2TiO5 powders prepared by hydrolytic sol-gel method are 1-2μm and 3.2m2/g.It is dropped to 0.1-0.3μm 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.