SiO2-Tolerant Grain-Boundary Conduction in Sr- and Mg-Doped Lanthanum Gallate

摘要

The effect of SiO2 impurity on the grain-boundary conduction in Sr- and Mg-doped lanthanum gallate La0.8Sr0.2Ga0.8Mg0.2O3, LSGM was studied. The grain-boundary conduction of LSGM was slightly affected, even by the addition of 500–2000 ppm SiO2, while the apparent grain-boundary resistivity was increased up to 780 times in gadolinia-doped ceria by the doping of 500–2000 ppm SiO2. The high tolerance of the grain-boundary conduction against siliceous impurity in the LSGM specimen was explained by the gathering of the acidic siliceous phase near the basic SrO component