DEFECT STRUCTURE AND DIFFUSE-SCATTERING OF ZIRCONIA SINGLE-CRYSTALS WITH 10-MOL-PERCENT AND 15-MOL-PERCENT CAO AT TEMPERATURES UP TO 1750-K

Disorder diffuse scattering of CaO-stabilized zirconia was measured fo r two different CaO concentrations at temperatures up to 1750 K. There is no qualitative difference between the two samples at any temperatu re. Within the limits of an energy resolution of 0.1 THz, the diffuse scattering is of static origin. A quantitative interpretation is given in terms of two basic types of microdomains. Correlations exist along the [111] directions. The correlation lengths are independent of conc entration and temperature, which only affect the relative amounts of u ncorrelated to correlated microdomains. A pronounced change was observ ed at temperatures between 1150 and 1350 K. According to the published phase diagrams phase changes occur in this temperature regime. The di ffuse scattering at very high temperatures seems to be in conflict wit h other interpretations based on precipitations of the CaZr4O9 (PHI1) structure.