Structural evolution in polyolysed hybrid organic-inorganic alumina gels

New material gels obtained by reaction of the aluminum sec-butoxide with pr opan-1,2-diol at room temperature without using a catalyst or adding water, have been pyrolyzed at different temperatures under argon and in air. The obtained products have been characterised by various methods (X-ray, IR and Raman spectroscopies, SEM and density measurements) to determine their str uctures. Corundum is formed at 1450 degrees C when the material is heat-tre ated under argon, but this phase is obtained rapidly at temperatures above 1000 degrees C for the xerogel pyrolysed in the air. (C) 2000 Kluwer Academ ic Publishers.