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

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• 作者：Vandana Shukla ; Ashutosh Kumar ; Ishamol Labbaveettil Basheer ; Kantesh Balani ; Anandh Subramaniam and Shobit Omar
• 刊名：Journal of the American Ceramic Society
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：100
• 期：1
• 页码：204-214
• 全文大小：1974K
• ISSN：1551-2916

文摘

The effect of replacing Sc₂O₃ with Yb₂O₃ on the structural and electrical properties of xYb₂O₃–(12–x)Sc₂O₃–88ZrO₂ 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 12ScSZ, 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 12ScSZ, 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 Sc₂O₃ with Yb₂O₃. In the intermediate temperature range, 1Yb11ScSZ exhibits the highest, while 12ScSZ shows the lowest conductivity values, which is attributed to corresponding phases present in that range. Through co-doping with >1 mol% Yb₂O₃ leads to conductivity decrease, but the value remains higher than that of 12ScSZ. A sharp conductivity change is observed in 12ScSZ and 1Yb11ScSZ samples, which is attributed to partial phase transition as well to the formation of cation-vacancy complexes. In this work, the beneficial effect of Yb₂O₃ co-doping in 12ScSZ on the phase and conductivity has been highlighted.