Combustion synthesis of gadolinia doped ceria powder

Gadolinia doped ceria (GDC) powders with different gadolinia content in the range 0-15 mol% were prepared by solution combustion route using a solution of cerium nitrate, gadolinium nitrate and citric acid. In the experiments citric acid to metal nitrate molar ratio was taken as 5:6. The solution on heating formed gel before combustion. Thermal analysis of the gel precursors containing different mol% gadolinia showed single step combustion reaction and the initiation temperature of the combustion reaction increased with gadolinia content. Surface area of the combustion synthesized powder was found to increase with increase in gadolinia content. In correlation with surface area results finer crystallite size was obtained in higher gadolinia content compositions. Particle agglomeration in high gadolinia content powders, when calcined at 600 deg. C, was observed and this was attributed to high reactivity of nano-crystalline powders. The combustion synthesized powders when sintered at 1250 deg. C resulted in pellets with density in the range 94-97% of theoretical density