Electrical properties and chemical stability of BaCe0.9Y0.1O3-BaWO4 composites synthesized by co-sintering and impregnation method

Abstract BaCeO 3 -based materials exhibit high electrical conductivity, however undergo degradation in CO 2 and H 2 O containing atmospheres. In this work the BaCe 0.9 Y 0.1 O 3 -BaWO 4 composites were prepared by co-sintering and via impregnation methods. The main motivation was to locate the barium tungstate on the grain boundary of Y-doped barium cerate and enhance the functional properties of final material comparing to single phase BaCe 0.9 Y 0.1 O 3 − δ . It was found that used synthesis procedures lead to two phase materials with doped barium cerate as the main phase and BaWO 4 as the second one. The Electrochemical Impedance Spectroscopy (EIS) measurements performed at dry air, 100% HR air and 5% H 2 in Ar atmospheres for temperature range 200–700 °C allowed to determine the electrical conductivity of synthesized materials. Introduction of BaWO 4 second phase into host BaCe 0.9 Y 0.1 O 3 − δ modified the electrical properties of bulk and grain boundary for materials synthesized by both co-sintering and for impregnation method. However, the effect of synthesis procedure was observed mainly for grain boundary contribution. Chemical resistance of composites toward CO 2 and water vapour was estimated based on the CO 2 /H 2 O exposure test in which samples were exposed to CO 2 and H 2 O rich atmosphere at 25 °C for 700 h. It was observed that chemical stability of composites in corrosive atmosphere was significantly higher comparing to single phase BaCe 0.9 Y 0.1 O 3 − δ regardless to the synthesis procedure.