Superplastic Phenomenon and Electric Properties of Sc{sub}2O{sub}3 Doped Zirconla-Based Ceramics

摘要

Scandia-doped zirconia has been found to be a very promising material for an electrolyte of solid oxide fuel cells (SOFC). If superplasticity occurs in the Sc{sub}2O{sub}3 doped ZrO{sub}2 polycrystals, then they can be formed into suitable shapes for the SOFC by plastic working. There have been, however, few studies on the superplasticity and its influence on the electric properties. In this study, five types of Sc{sub}2O{sub}3 doped ZrO{sub}2 specimens were prepared and were first deformed in bending and then in tension at elevated temperatures to examine whether superplasticity could occur. The flexural tests revealed that all specimens could show m-values larger than 0.5. The 4 mol% Sc{sub}2O{sub}3 doped ZrOz showed elongation no less than 200% in tension, while other specimens including 10Sc{sub}2O{sub}3-lCeO{sub}2-89ZrO{sub}2 showed limited elongations. The effect of the deformations on the ionic conductivity of the specimens was studied by the AC impedance method. It was found that the deformations had only a little effect on the conductivity.