Preparation of Doped Ceria Powder

Abstract

The alleged poor sinterability of (doped) ceria was studied for the application as a fuel cell solid electrolyte, and a solution has been proposed. Yttria doped ceria (YDC) powder Ce{sub 0.667}Y{sub 0.333}O{sub 1.833} was prepared by oxalate coprecipitation through addition of a concentrated yttrium-cerium nitrate solution to a dilute aqueous on of a concentrated oxalic acid solution at neutral pH. The precipitate was washed with alcohol and calcined at 700 C. Coprecipitation conditions were critical for the quality of the resulting oxide powder, of which the average particle size was a key parameter. Compacted into pellets, relative densities attained >95% and >98% of theoretical after firing for 4 hours at 1,300 C and 1,500 C respectively. Sample ``embedding`` with YDC powder further improved the final density. Standard conductivity behavior of the samples was observed. The powder could equally be tape cast and sintered to dense films.