abstract
Minor additions of manganese oxide and cobalt oxide are both shown to be good sintering, aids for a Ce0.8Pr0.2O2-delta promising ceramic membrane material with comparable values Of partial oxygen-ionic and electronic conductivities, to offer dense ceramics with submicron grain under 1150 degrees C. Transmission electron microscopy and X-ray energy dispersive spectroscopy suggest the transition-metal oxide addition to be located in the grain boundary regions. The smallest grain size is observed in the case of materials with Mn additions. Whereas the addition of cobalt oxide radically improves the transport properties boosting, the level of electronic conductivity by two to three times and leaving the ionic conductivity intact, the addition of manganese oxide is Shown to he detrimental, increasing the activation energy for ionic Conductivity while offering no benefit to electronic conductivity. These characteristic transport properties impact oil levels of oxygen permeation. The flux is significantly improved ill the case of Co additions due to an increased ambipolar conductivity and improved oxygen surface kinetics, whereas no improvement ill oxygen permeation flux is observed for Mn additions in comparison to the base composition It has been suggested that a very slight increase ill solubility Of the transition oxide addition in the grain bulk in the Mn-doped case may offer all explanation of the resultant properties. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3068396] All rights reserved.
keywords
CERIA SOLID-SOLUTIONS; THERMAL-EXPANSION; DOPED CERIA; ELECTRICAL-CONDUCTIVITY; MIXED CONDUCTORS; ELECTRONIC TRANSPORT; FUEL-CELLS; CEO2; PERMEABILITY; AIDS
subject category
Electrochemistry; Materials Science
authors
Fagg, DP; Garcia-Martin, S; Pascual, MJ; Kharton, VV; Frade, JR
our authors
Jorge Ribeiro Frade
Retired Professor
Vladislav Kharton
Invited Principal Researcheracknowledgements
This work was supported by the Fundacao para a Ciencia e a Tecnologia (FCT), Portugal (project no. PTDC/CTM/66243/2006, no. SFRH/BPD/3529/2000, no. REEQ/CTM/2005), the Ministerio de Educacion y Ciencia (MEC), Spain (project no. MAT2007-64486-C07-04), and Autonomous Community of Madrid (CAM), Spain (project no. MATERYENER S 505/PPQ/0358). The authors also thank the Microscopy Center Luis Bru from Universidad Complutense Madrid (UCM) for technical assistance.