Thermodynamic description of the nonstoichiometric defect structure in Ce1−xZrxO2 solid solution powders

Abstract : Equilibria between gaseous oxygen (from 870 to 20 000 Pa) and several high surface area Ce1−xZrxO2 powders (0≤x≤0.36) were studied by means of thermogravimetry in order to get a better insight into the nature and behaviour of the point defects in these solid solutions. By measuring the weight changes between two different oxygen pressures, we could obtain the variations of the oxygen vacancy concentration at the surface of the solutions as a function of the oxygen pressure and zirconium concentration. The anionic sublattice was shown to follow an ideal thermodynamic behaviour, the oxygen vacancy concentration being proportional to PO2−1/6. By comparing the experimental and theoretical variations of the oxygen vacancy concentration versus the zirconium concentration, we found that the cationic sublattice was well described by a nonideal (regular) model in which the activity coefficients of the structural elements CeCex, ZrCex and of the associated defect (ZrCe, CeCe′)′ are different from 1.
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Solid State Ionics, Elsevier, 2000, 127 (3-4), pp.207-222. 〈10.1016/S0167-2738(99)00289-1〉
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https://hal-emse.ccsd.cnrs.fr/emse-00609172
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Soumis le : lundi 18 juillet 2011 - 14:26:04
Dernière modification le : jeudi 11 janvier 2018 - 06:21:23

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Catherine Janvier, Michèle Pijolat, Françoise Valdivieso, Michel Soustelle. Thermodynamic description of the nonstoichiometric defect structure in Ce1−xZrxO2 solid solution powders. Solid State Ionics, Elsevier, 2000, 127 (3-4), pp.207-222. 〈10.1016/S0167-2738(99)00289-1〉. 〈emse-00609172〉

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