Structural phase relationship, sintering behavior and conducting property of Ba1 − xSrxZr0.9Y0.1O3 − δ

• The density of Ba1-xSrxZr0.9Y0.1O3-δ ceramics increases with increasing x.
• Electrical conductivity at grain boundary increases by increasing the density.
• Electrical conductivity in grain also increases with increasing Sr content.

Crystal structure, sinterability and electrical conductivity of proton conducting Ba1 − xSrxZr0.9Y0.1O3 − δ were investigated. Crystal structure varies from cubic, tetragonal, body-centered orthorhombic to primitive orthorhombic with increasing Sr content, which shows the same tendency with Ba1 − xSrxZrO3. With Sr substitution, sinterability and grain growth of Ba1 − xSrxZr0.9Y0.1O3 − δ increase and sintering density more than 92% is realized for the ceramic specimens with x ≥ 0.4 even at sintering temperature of 1600 °C. Due to improvement of sinterability and grain growth, the electrical conductivity at grain boundary is enhanced by Sr substitution, resulting in total electrical conductivity of Ba0.6Sr0.4Zr0.9Y0.1O3 − δ high. The improvement of bulk electrical conductivity is also observed by Sr substitution, suggesting high potential as superior proton conductor in Ba0.6Sr0.4Zr0.9Y0.1O3 − δ.