Synthesis and sintering of Gd-doped CeO2 nanopowders prepared by ultrasonic spray pyrolysis

Ultrasonic spray pyrolysis (USP) of nitrate-based precursors was used to fabricate fine and polycrystalline Ce_0.8Gd_0.2O_1.9 (CGO) powders with controlled microstructure in a one-step process varying four spray-pyrolysis parameters: precursor solution concentration, atomizing frequency, carrier gas flow rate, and pyrolysis temperature. A design of experiment (DOE) was used to understand the independent and combined influences of these process parameters on the particle size, particle size distribution and crystallite size. In this study, smaller CGO particles with narrower particle size distribution and finer grain size showed a full densification starting at a low temperature. CGO densification was found to be strongly dependent on CGO powder microstructural properties.