ABSTRACT
The solid solution powders of the Sc2O3–ZrO2 system have been prepared by a sol–gel method. The phases and the electrical conductivity of the sintered Sc2O3–ZrO2 (ScSZ) and ScSZ-Al2O3 have been examined. ZrO2 with 3 mol% (3ScSZ) and 8 mol% (8ScSZ) Sc2O3 showed the single phase of the tetragonal (t) and cubic (c) structure, respectively. The samples with 11 mol% (HScSZ) and 12 mol% (12ScSZ) Sc2O3 showed the rhombohedral structure. The com posites of these zirconias had the cubic structure in a content range 0.7–30 wt% Al2O3. The electrical conductivity of 8ScSZ and 12 ScSZ was 0.34 S/cm at 1000 °C. The cubic stabilized zirconia with low content of Sc2O3 showed a significant aging effect and the conductivity of 8ScSZ decreased to 0.14 S/cm after annealing at 1000 °C for 1000h. The conductivity of the ScSZ and Al2O3 composites decreased with increasing Al2O3 content. The conductivity of 11ScSZ–20 wt% Al2O3 was 0.15 S/cm at 1000°C and no change with annealing at 1000°C was observed.
