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Nanocrystalline gadolinium doped ceria: Combustion synthesis and electrical characterization
, S. Patra, V. Bedekar, A.K. Tyagi, R.N. Basu
Published in
Volume: 9
Issue: 5
Pages: 3075 - 3083
Twenty mol% gadolinium doped ceria powders were prepared by citrate-nitrate combustion synthesis technique. Two different sources of cerium viz. cerium nitrate and ammonium eerie nitrate were used in different oxidant-to-fuel ratios. The crystallite size of the synthesized powders ranged 5-27 nm was obtained depending on the preparation conditions with average particle size in the range 0.64-1.26 pm. Although, the powders were found to be agglomerated in nature, these powders were highly sinter-active as they showed very high sintered density (>95%) when sintered at 1250 °C having grain size in the range of 200-500 nm. The electrical conductivity was found to depend on the temperature with two distinct regimes at a transition point of 350 "C. The grain boundary showed a significant role in the total conductivity with its activation energy dependent on the material preparation conditions. The activation energy of total conduction was found to be significantly low (~0.5 eV) in the temperature range of 400-700 °C, this property is unique for application as an electrolyte for solid oxide fuel cell operating in the low temperature range. It was found that a fuel-deficient combustion reaction using cerium nitrate as the oxidant yielded the best quality powder which showed a maximum electrical conductivity of ~1.74 x 10~2 S/cm at 600 °C. Copyright © 2009 American Scientific Publishers All rights reserved.
About the journal
JournalJournal of Nanoscience and Nanotechnology