SYNTHESIS AND SINTERING OF ZIRCONIUM-OXIDE AEROGEL

Crystalline zirconium oxide aerogel was synthesised by supercritical d rying of a precursor gel prepared in the zirconium n-propoxide, n-prop anol, acetylacetone and water system;This aerogel retained the initial fractal structure of the gel state. Aerogel samples were heated at mo derate temperatures and studied by X-ray diffraction and small angle X -ray scattering. Small angle X-ray scattering results strongly suggest ed that the structural modifications follow the linear Cahn's theory f or spinodal decomposition. Upon higher temperature annealing, the low- ri intensity maximum, present on small angle X-ray scattering curves, began to move towards higher-q vectors before moving back. to smaller angles. The aerogel sintering mechanism changed and crossed from sinte ring of crystalline mass fractal aggregates towards the conventional b ehaviour. (C) 1998 Elsevier Science B.V. All rights reserved.