Low temperature fabrication of (Y,Gd,Sm)-doped ceria electrolyte
A general procedure based on the oxalate coprecipitation route was developed to produce very sinterable ceria (CeO2) powder doped with Gd2O3, Sm2O3 or Y2O3. The method is simple, reliable and very reproducible. Without any milling step, powder of 20 mol% GdO1.5, SmO1.5 or YO1.5-CeO2 could be fired translucent dense (97% relative to theoretical) at 1300 °C (4 h) already, as pressed compacts. This compares to typical values of 95% relative density obtained after firing at 1500–1600 °C in the standard literature. Cast tapes from the intensively milled powders were fired equally dense at 1400 °C (2 h), among the best results yet reported for tape cast doped ceria. Owing to their high density, excellent ionic conductivity values were observed for the doped ceria electrolytes, on the order of 5–7 S m−1 at 750 °C in air.