Aging and Raman scattering study of scandia and yttria doped zirconia

The changes of electrical conductivity during annealing at 1273 K in stabilized zirconia with 8 mol% Y2O3 (8YSZ), 8 mol% Sc2O3 (8ScSZ) and 11 mol% Sc2O3 (11ScSZ) have been examined. 8YSZ and 8ScSZ showed significant decrease in conductivity during the initial stage of annealing, whereas 11ScSZ showed no conductivity decrease. The Raman scattering technique was used to analyze the phase change in the annealed samples. The observed Raman spectrum suggested that the conductivity decrease in 8YSZ and 8ScSZ was caused by a local ordering toward the formation of tetragonal phase in the cubic matrix by annealing at 1273 K.