Internal distortion in ZrO2-CeO2 solid solutions:: Neutron and high-resolution synchrotron x-ray diffraction study

Neutron and high-resolution synchrotron x-ray diffraction measurements have indicated a tetragonal zirconia phase with both an axial ratio of unity and internal shear deformation: The oxygen displacements from ideal fluorite positions of 0.088 and 0.078 Angstrom are observed for 65 and 70 mol % CeO2-ZrO2 samples, respectively, although both c/a values are 1.000+/-0.001, The c/a ratio decreases with increasing of CeO2 content and decreases discontinuously to unity around a 60 mol % CeO2 composition, while the oxygen displacement decreases continuously up to about 90 mol % CeO2. (C) 1998 American Institute of Physics.