Microstructures and proton conductivities of BaZrO3 modified by BaCeO3

Abstract

The dense sintered bodies with >95% theoretical densities were successfully obtained from the BaZrO3, BaCeO3, Ba(Zr 0.7Ce0.3)O3 solid solution, and core-shell structured 0.7BaZrO3-0.3BaCeO3 composite powders prepared by sol-gel methods. The activation energy of Ba(Zr0.7Ce 0.3)O3 solid solution calculated from the Arrhenius plot of the proton conductivities was similar to that of BaZrO3. The activation energy of core-shell structured 0.7BaZrO3-0.3BaCeO 3 composite, however, was much lower than that of BaZrO3 or Ba(Zr0.7Ce0.3)O3 solid solution, and was very similar to that BaCeO3. These results could be assigned to the Ce-rich grain boundary which was clearly observed by EDX in core-shell structured 0.7BaZrO3-0.3BaCeO3 composite.