LOW-TEMPERATURE SINTERING OF SEEDED ALUMINUM TITANATE PRECURSOR GELS

Aluminium titanate has been prepared by thermal decomposition of a pre cursor gel formed by the controlled flocculation of a homogeneous mixt ure of boehmite and titanium isopropoxide sols. The effect of aluminiu m titanate seed nuclei, with average size less than 0.25 mm, on the ph ase formation, densification and microstructure development is reporte d. The results indicate enhanced densification kinetics for the seeded precursor. Such gels after calcination at 1000 degrees C for 2 h were sintered to densities of similar to 96% at 1300 degrees C for 30 min. Nearly complete formation of the aluminium titanate phase was achieve d under the present experimental conditions. A simultaneous densificat ion and phase formation from a liquid phase assisted titania rich prec ursor is suggested. On the other hand the unseeded gels could achieve only < 85% densification under identical conditions. (C) 1997 Elsevier Science B.V.