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

Synthesis, ionic conductivity, and ageing behavior of [ x Y 2 O 3 –(10 − x ) Sc 2 O 3 ]–90 ZrO 2 ( x = 2, 3, 4, and 5 mol%) as well as 10–11 mol% Sc 2 O 3 –ZrO 2 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 1200–2700 h. Low resistivity degradation of Y-doped ScSZ not exceeded 10% during extended annealing for 2700 h 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.