A systematic investigation of Y-doped BaZrO3 was performed with regard to the relationship between dopant concentration, microstructures and grain-boundary conductivity. As the Y concentration increased, the average grain diameter increased 4-fold but the trend in grain-boundary character was not changed. Random boundaries were predominant in all samples. The grain-boundary conductivity increased by 3 orders of magnitude, and the activation energy decreased with increasing Y concentrations from 5 to 15mol%. No secondary phase was observed in 5mol%Y-doped BaZrO3. The results confirmed that the contributions of the observed parameters to grain-boundary conductivity were low. Therefore, the contribution of space charge layers was probably high in Y-doped BaZrO3.

Microstructures and Grain Boundary Conductivity of BaZr1−xYxO3 (x = 0.05, 0.10, 0.15) Ceramics. F.Iguchi, N.Sata, T.Tsurui, H.Yugami: Solid State Ionics, 2007, 178[7-10], 691-5