DIFFUSE-SCATTERING IN YTTRIA-STABILIZED CUBIC ZIRCONIA

We have used a position-sensitive detector (PSD) system to make measurements of the diffuse X-ray scattering on a cubic Y2O3-stabilized zirconia, Zr0.61Y0.39O1.805, in far greater detail than has hitherto been reported. In addition to the fairly prominent diffuse peaks visible in 〈1 1 0〉 sections that have been the center of discussion in many previous studies we see a number of other characteristic diffraction features. We report results of some Monte Carlo simulations in which we attempt to find the origins of these various features. We believe one feature, in the form of sets of dark planes normal to 〈1 1 0〉, occurs because of size-effect-like strains induced along 〈1 1 0〉 intermetal vectors, and is only visible because of the similarity of the scattering factors for Zr and Y. A second feature, in the form of bow-tie-shaped regions of scattering, originates from the same basic strains but the symmetry of these requires that displacements in the [1 1 0] direction are out of phase with those in the [1 - 1 0], implying a distortion of the basic metal coordination such that an expansion along [1 1 0] is accompanied by a contraction along [1 - 1 0]. © 1992.