Effects of strontium gallate addition on sintering behavior and electrical conductivity of yttria-doped ceria

The densification behavior and electrical conductivity of Ce 0.8 Y 0.2 O 1.9 ceramics with strontium gallate concentrations ranging from 0 to 5 mol. % were investigated. The sintered density was found to increase rapidly for concentrations up to 0.5 mol. % Sr 2 Ga 2 O 5 and then to decrease upon further Sr 2 Ga 2 O 5 addition. It was possible to obtain dense Ce 0.8 Y 0.2 O 1.9 ceramics with 95% of the theoretical density using a 0.5 mol. % Sr 2 Ga 2 O 5 -added specimen sintered at 1250°C for 5 h, whereas pure Ce 0.8 Y 0.2 O 1.9 ceramics needed to be sintered at 1550°C in order to obtain an equivalent theoretical density. The electrical conductivity was measured as a function of the dopant content over the temperature range of 450°C–700°C in air. The conductivity of the 0.5 mol. % Sr 2 Ga 2 O 5 -added specimen showed a maximum value of 4.43 × 10 −3 Ω −1 ·cm −1 at 700°C. The addition of Sr 2 Ga 2 O 5 was found to promote the sintering properties and electrical conductivities of Y 2 O 3 -doped CeO 2 .