SHORT-RANGE STRUCTURE OF ZIRCONIA XEROGEL AND AEROGEL, DETERMINED BY WIDE-ANGLE X-RAY-SCATTERING

The short-range structure of amorphous zirconia, investigated by X-ray diffraction, has been found to bear more resemblance to the monoclinic ZrO2 structure than it does to the tetragonal structure. This result was achieved in two zirconia samples (xerogel and aerogel) by analyzing both the positions of the maxima of the experimental (Fourier-transformed) 'reduced' radial correlation function, G(r), and the experimental radial atom (number) density distribution, p(r). This latter function was simulated as a weighted sum of three partial atom density distributions, ρ{variant}′ZrO, ρ{variant}′ZrZr, and τ′OO, based on the monoclinic or the tetragonal coordination frame and limited inside a sphere of 9 Å in radius. The coordination statistics are described in terms of sums of Gaussian functions into which distortion effects (first-type and second-type disorder) were introduced. © 1993.