This title appears in the Scientific Report : 2003 

Grain size dependent grain boundary defect structure: case of doped zirconia
Guo, X.
Zhang, Z.
Elektrokeramische Materialien; IFF-EKM
Acta materialia, 51 (2003) S. 2539 - 2547
Amsterdam [u.a.] Elsevier Science 2003
2539 - 2547
10.1016/S1359-6454(03)00052-1
Journal Article
Kondensierte Materie
Acta Materialia 51
J
Please use the identifier: http://dx.doi.org/10.1016/S1359-6454(03)00052-1 in citations.
The electrical properties of 3 mol% Y2O3 doped ZrO2 were measured by impedance spectroscopy as a function of grain size, and the microstructure studied by SEM and HREM. In spite of the very clean grain boundaries, the grain boundary conductivity was still found to be similar to2 orders of magnitude lower than the bulk conductivity, while it increased with decreasing grain size. The low grain boundary conductivity, according to the Schottky barrier model, is due to the depletion of oxygen vacancies in the grain boundary space charge layers. Within this framework, the grain boundary space charge potential and the concentration of oxygen vacancies in the space charge layers were calculated; it was found that the space charge potential decreased, but the oxygen vacancy concentration increased with decreasing grain size. Analyses of literature results for 8.2 mol% Y2O3 and 15 mol% CaO doped ZrO2, respectively, revealed similar phenomena. (C) 2003 Published by Elsevier Science Ltd on behalf of Acta Materialia Inc.