Segregation effects in sol-gel zirconia-silica materials analyzed through their radial distribution functions

A novel method to characterize segregation effects in silica-zirconia materials prepared by the sol-gel method through the alkoxide route is reported. These segregation effects were studied by using the Radial Distribution Function obtained from the X-ray diffractograms. The information obtained by this technique allows one to predict the spatial distribution of one of the oxides into the other as a function of the annealing temperature and the relative concentration of both constituents. Silica and Zirconia were chosen for preparing the alloys since Si and Zr have the same oxidation state and, in spite of both ions being of different atomic radius, they do not produce distortion in the oxygen sub-lattice (due to an oxygen deficiency) which could influence the spatial distribution of both cations into the lattice. Received: 4 May 1999 / Reviewed and accepted: 14 September 1999