LOW-TEMPERATURE FABRICATION OF (Y,GD,SM)-DOPED CERIA ELECTROLYTE

A general procedure based on the oxalate coprecipitation route was dev eloped 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-C eO2 could be fired translucent dense (97% relative to theoretical) at 1300 degrees C (4 h) already, as pressed compacts. This compares to ty pical values of 95% relative density obtained after firing at 1500-160 0 degrees C in the standard literature. Cast tapes from the intensivel y milled powders were fired equally dense at 1400 degrees C (2 h), amo ng the best results yet reported for tape cast doped ceria. Owing to t heir high density, excellent ionic conductivity values were observed f or the doped ceria electrolytes, on the order of 5-7 S m(-1) at 750 de grees C in air.