Abstract
Ce 0.9Gd 0.1O 2− δ powder was prepared by oxalate coprecipitation. Fe 2O 3 (0.5 at.%) was loaded into the powder through two approaches—mechanical mixing and wet chemical loading. The densification behavior, microstructure and electrical properties of the unloaded and Fe-loaded Ce 0.9Gd 0.1O 2− δ ceramics, sintered at temperatures ranging from 1000 to 1550 °C for 5 h, were investigated. Both the Fe loading and the loading method exhibited a remarkable effect on the densification of Ce 0.9Gd 0.1O 2− δ ceramics. The Fe loading by chemical way was more effective in promoting densification in the temperature range less than 1300 °C, as compared to that by mechanical mixing. However, the two different ways for Fe loading led to a very similar way in affecting the grain boundary (GB) conduction of the Ce 0.9Gd 0.1O 2− δ ceramics. The GB conductance of the Fe-doped Ce 0.9Gd 0.1O 2− δ ceramics experienced a rapid increase from 1100 to 1250 °C, reached a relatively broad maximum over 1250–1500 °C, and finally decreased at >1500 °C. This was completely different from the variation in the GB conduction of the unloaded samples with temperature, which decreased consistently with increasing sintering temperature. The Fe 2O 3 dopant exhibited the optimal scavenging effect in the temperature range of 1250–1500 °C, in which a higher total conductivity and a lower activation energy for the total conduction were achieved for Ce 0.9Gd 0.1O 2− δ ceramics. Finally, the possible mechanisms related to the enhanced densification behavior and the improved GB conduction of the Ce 0.9Gd 0.1O 2− δ ceramics due to Fe loading were discussed.
Published Version
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