MAUVY, Fabrice; BASSAT, Jean-Marc.; BOEHM, Emmanuelle; DORDOR, Patrice; LOUP, J. P.

doi:10.1016/S0167-2738(02)00903-7

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MAUVY, Fabrice
Institut de Chimie de la Matière Condensée de Bordeaux [ICMCB]

BASSAT, Jean-Marc.
Institut de Chimie de la Matière Condensée de Bordeaux [ICMCB]

BOEHM, Emmanuelle
Institut de Chimie de la Matière Condensée de Bordeaux [ICMCB]

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Solid State Ionics. 2003, vol. 158, n° 3-4, p. 395-407

Elsevier

Résumé en anglais

In mixed electronic and ionic conductors O2−/e− (MIEC), where the electronic conductivity is dominant, the determination of the oxygen diffusion coefficient is an essential feature. In the present paper, the oxygen chemical diffusion coefficient O of a MIEC oxide has been evaluated using the conductivity relaxation method, in the temperature range 773–1173 K. Samples of La2Cu0.5Ni0.5O4+δ were selected because of the high value of their surface exchange coefficient. In addition, the oxygen diffusion coefficient D* was determined from the 18O tracer diffusion profile. Finally, the oxygen partial pressure dependence of this compound was determined by thermogravimetric analysis (TGA). On the basis of these three independent experiments, the model of ambipolar diffusion, which describes the diffusion in mixed oxide, has been experimentally verified. For such a determination of the intrinsic diffusion characteristics, dense samples are required.< Réduire

Mots clés en anglais

Conductivity relaxation

Chemical diffusion coefficient

Tracer diffusion

Wagner model

Mixed conductors

La2Cu0.5Ni0.5O4+δ

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Measurement of chemical and tracer diffusion coefficients of oxygen in La2Cu0.5Ni0.5O4+δ

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