Sintering Behavior of In Situ Cobalt Oxide‐Doped Cerium–Gadolinium Oxide Prepared by Flame Spray Pyrolysis

Ce 0.9 Gd 0.1 O 1.95 (CGO10) and in situ cobalt oxide‐doped CGO10 were prepared by pilot‐scale flame spray synthesis, yielding powders with an average particle size of 40 nm. Cobalt oxide was shown to be a very effective sintering aid for CGO10 and lowered the maximum sintering temperature from 1450° to about 1200°C. Sintering studies revealed that in situ cobalt oxide‐doped CGO10 exhibited a temperature of maximum shrinkage rate of 880°C for a dopant concentration of 1 mol% CoO 1− x , whereas for conventionally cobalt oxide‐doped CGO10, this temperature was 914°C. This decrease is believed to be a result of a more homogeneous dopant distribution of the in situ cobalt oxide‐doped CGO nanopowders as compared with the powders in which the doping was introduced as nitrates.