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Spark Plasma Sintering and Hot Pressing of Hetero-Doped LaNbO4

Syvertsen, Guttorm E. and Estournès, Claude and Fjeld, Harald and Haugsrud, Reidar and Einarsrud, Mari-Ann and Grande, Tor Spark Plasma Sintering and Hot Pressing of Hetero-Doped LaNbO4. (2012) Journal of the American Ceramic Society, 95 (5). 1563-1571. ISSN 0002-7820

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Official URL: http://dx.doi.org/10.1111/j.1551-2916.2012.05101.x

Abstract

LaNbO4/La3NbO7 and LaNbO4/LaNb3O9 cer-cer composites were prepared by impregnating Ca-doped LaNbO4 powder, synthesized by spray pyrolysis, with La- or Nb-precursor solutions. The sintering of the calcined powders was investigated by dilatometry, and dense composites were prepared by conventional sintering, hot pressing, and spark plasma sintering. The particle size of the starting powders was about 50 nm, and the average grain size of the dense materials ranged from 100 nm and upwards, depending on the sintering temperature, sintering procedure, and the phase composition. The unit cell parameters of LaNbO4 showed a finite size effect and approached the cell parameters of tetragonal LaNbO4 with decreasing crystallite size, both for the single-phase material and the composites. The minority phase (La3NbO7 or LaNb3O9) were observed as isolated grains and accumulated at triple points and not along the grain boundaries, pointing to a large dihedral angle between the phases. The calcium-solubility in the minority phases was larger than in LaNbO4, which corresponds well with previous reports. The electrical conductivity of the heterodoped materials was similar to, or lower than, that for Ca-doped LaNbO4.

Item Type:Article
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT (FRANCE)
Other partners > Norwegian University of Science and Technology - NTNU (NORWAY)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UPS (FRANCE)
Other partners > University of Oslo (NORWAY)
Laboratory name:
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Deposited By: cirimat webmestre
Deposited On:21 Aug 2013 12:38

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