Scandia-stabilized zirconia doped with yttria: Synthesis, properties, and ageing behavior

Abstract

Synthesis, ionic conductivity, and ageing behavior of [x Y2O3–(10−x) Sc2O3]–90 ZrO2 (x=2, 3, 4, and 5mol%) as well as 10–11mol% Sc2O3–ZrO2 electrolytes are presented. High dense homogeneous ceramic samples with fine microstructure were prepared from laser synthesized mixed nanopowders 10YSZ and 10ScSZ using low sintering temperatures of 1010–1300°C. Stabilization of cubic fluorite-type phase has been achieved for Y-doped ScSZ composites at these temperatures. It is shown that the DC conductivity of the Y-doped ScSZs decreases proportionally to the yttria content throughout the temperature range studied, from 500 to 900 °C. Ageing behavior of the electrolytes was studied at 850°C for 1200–2700h. Low resistivity degradation of Y-doped ScSZ not exceeded 10% during extended annealing for 2700h has been obtained for the samples sintered below 1100°C. High and stable conductivity has been obtained for 10ScSZ and 11ScSZ. Any decrease in their conductivity during extended annealing was not detected.