Influence of Cu on the properties of gadolinium-doped barium cerate

In the present work the effect of copper oxide addition on the densification behavior and electrical conductivity of BaCe1−xGdxO3−δ (BCG) type ceramics is investigated. Small addition (1 mol%) of this sintering additive reduces both the calcination temperature (by ~250 °C) and the sintering temperature (by ~150 °C) and promotes at the same time the densification process. According to the X-ray diffraction analysis the BaCe1−xGdxO3−δ samples with 0 ≤ x ≤ 0.2 and the BaCe0.9−yGd0.1CuyO3−δ samples with 0.0075 ≤ y ≤ 0.07 are single-phase. It was found that the samples with Cu, when sintered at 1450 °C for 3 h, have ~95% of relative density compared with pure BaCe0.9Gd0.1O3−δ samples that have ~86%. It was also found that the electrical conductivity of Cu-containing samples sintered at 1450 °C is comparable to those without Cu sintered at 1600 °C in oxidizing and reducing atmospheres. Cu-containing samples exhibit significantly higher conductivity in both air and hydrogen atmosphere.