Structural Characteristics and Electrical Conductivity of Spark Plasma Sintered Ytterbia Co‐doped Scandia Stabilized Zirconia

The effect of replacing Sc 2 O 3 with Yb 2 O 3 on the structural and electrical properties of x Y b 2 O 3 –(12– x )Sc 2 O 3 –88ZrO 2 has been investigated. Spark plasma sintering technique is employed to fabricate dense bulk samples from the nano‐sized powders. X‐ray diffraction and transmission electron microscopy performed on pellets indicate the existence of cubic and rhombohedral phases in 12Sc SZ , and a single cubic phase in all the co‐doped compositions. However, Raman spectroscopic studies suggest the presence of a metastable tetragonal t ″‐phase along with rhombohedral phases in 12Sc SZ , whereas a single cubic phase in all the co‐doped compositions. Significant enhancement in the conductivity of grain and grain boundary is observed on replacing Sc 2 O 3 with Yb 2 O 3 . In the intermediate temperature range, 1Yb11Sc SZ exhibits the highest, while 12Sc SZ shows the lowest conductivity values, which is attributed to corresponding phases present in that range. Through co‐doping with >1 mol% Yb 2 O 3 leads to conductivity decrease, but the value remains higher than that of 12Sc SZ . A sharp conductivity change is observed in 12Sc SZ and 1Yb11Sc SZ samples, which is attributed to partial phase transition as well to the formation of cation‐vacancy complexes. In this work, the beneficial effect of Yb 2 O 3 co‐doping in 12Sc SZ on the phase and conductivity has been highlighted.