NONHYDROLYTIC SOL-GEL PROCESS - ALUMINUM TITANATE GELS

The efficiency of the nonhydrolytic sol-gel process based on the conde nsation between metal chlorides and metal alkoxides has been studied i n the preparation of aluminum titanate gels. Solutions of aluminum and titanium precursors in the ratio Al/Ti = 2 gave gels with the same me tal ratio. The structural evolution of the samples is unusual; they di rectly crystallize at T > 600 degrees C into metastable pseudo-brookit e beta-Al2TiO5 and are reluctant to decompose into stable TiO2 (rutile ) and alpha-Al2O3 at 1150 degrees C. This behavior must be connected t o the high homogeneity of the samples originating from the nonhydrolyt ic sol-gel process.