STABILIZATION OF ALUMINA TOWARD THERMAL SINTERING BY SILICON ADDITION

The thermal stability of gamma alumina toward sintering at high temperatures (in the 1050-1220°C range) in the presence of steam has been studied from both structural and textural points of view. Improvement of the stabilization of alumina has been found be grafting silicon-containing compounds on the alumina surface. A reaction between the hydroxyl groups of alumina and the silicon-containing precursor was found to occur. The silicon-modified alumina is constituted by a layer of silica firmly bonded to the alumina support. The stabilization increases with increasing silicon loadings and reaches a plateau for ca. 3 wt% silicon. © 1991.