In the ZrO2sngbnd;CaO system cubic solid solutions of the fluoritehyphen;type structure are formed between 12 and 22 mole CaO for specimens fired at 2000deg;C and subsequently quenched from 1400deg;C. The lattice parameter increased linearly from 5.125 to 5.144 Aring; with increasing CaO content. Results of xhyphen;ray diffraction intensity studies favored the oxygenhyphen;ion vacancy model over the cation interstitial model for these solid solutions. As the CaO content was increased from 13 to 20 mole , the electrical conductivity at 1000deg;C decreased from 5times;10mdash;2to 6times;10mdash;3OHgr;mdash;1cmmdash;1and the activation energy increased from 1.11 to 1.35 eV. Specimens heated at 1000deg;C for one week showed extra xhyphen;ray diffraction lines. These data coupled with accompanying changes in electrical conductivity are discussed in terms of an ordermdash;disorder transition.
展开▼
