Microstructure and transport properties of Y-doped zirconia and Gd-doped ceria

Transmission electron microscopy (TEM) characterization has allowed us to show the influence of the microstructure on the grain boundary electrical conductivity (σgb) of Y-doped zirconia (YSZ) and Gd-doped ceria. For the Y2O3 (9 mol%)-doped zirconia samples, σgb increases with the grain size and the results depend on the powder elaboration process and sintering conditions. These effects are due to wettability changes of the glassy phases at the grain boundaries. On the contrary, for the Gd2O3 (10 mol%)-doped ceria samples, σgb decreases when the grain size increases and the results are not influenced by the batch of powder likely due to grain boundaries free of detectable glassy phases.