Oxygen stoichiometry, unit cell volume, and thermodynamic quantities of perovskite-type oxides

Girdauskaite, E.; Ullmann, H.; Daroukh, Mahmoud Al; Vashook, V.; Bülow, Martin; Guth, U.

doi:10.1007/s10008-006-0175-2

Cited by 23 publications

(21 citation statements)

References 20 publications

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“…[30][31][32][33] The value of d has a similar dependence on the oxygen partial pressure and temperature, typically found in the range of 0.35-0.65. Here, d ¼ 0.5 was adopted to calculate the kinetic constants in the investigated temperatures without causing significant errors.…”

Section: Kinetic Parametersmentioning

confidence: 83%

Permeation model and experimental investigation of mixed conducting membranes

Zhu

Liu

et al. 2011

AIChE Journal

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A simple oxygen permeation model was developed based on the theoretical analysis of the role of interfaces of mixed conducting membranes. The developed model equations contain three resistance constants, which can be determined by correlating oxygen permeation flux to oxygen partial pressure on each side. A series of experimental measurements of oxygen fluxes of Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3À membranes over a wide range of temperature and oxygen partial pressures were tested for the regression of three resistance constants with good correlation (R > 0.997). With this model, the interfacial exchange resistances of each side can be well distinguished from the bulk-diffusion resistance under a wide-temperature range. The kinetics parameters, including interfacial exchange coefficients on each side and ionic diffusion coefficient, can be obtained through the three resistance constants. Parametric studies can predict the influences of membrane thickness, oxygen partial pressures on oxygen flux, distribution of permeation resistances, and characteristic thickness.

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Section: Kinetic Parametersmentioning

confidence: 83%

Permeation model and experimental investigation of mixed conducting membranes

Zhu

Liu

et al. 2011

AIChE Journal

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“…Initially developed as an oxygen separation membrane [2], BSCF is a mixed ionic electronic conductor (MIEC) deriving its high oxygen ion conductivity from its oxygen-deficient perovskite structure. The oxygen nonstoichiometry of BSCF5582 has been measured by several researchers with the reported values of δ ranging from ∼0.2 to 0.8 depending on temperature, oxygen partial pressure, and method of measurement [3][4][5][6]. Chen et al [7] reported roomtemperature δ values ranging from 0.17 to 0.32 for BSCF with varying Co:Fe ratios.…”

Section: Introductionmentioning

confidence: 97%

The electronic conductivity of Ba0.5Sr0.5Co x Fe1−x O3−δ (BSCF: x = 0 ∼ 1.0) under different oxygen partial pressures

2009

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The electronic conductivity of sintered BSCF ceramics (Ba 0.5 Sr 0.5 Co x Fe 1−x O 3−δ , 0≤x≤1) was measured as a function of temperature up to 1273 K in air. The conductivity of BSC is thermally activated over 298-1273 K with an activation energy of 0.21 eV. The conductivity of BSF and BSCF (0.2≤x≤0.8) is thermally activated below ∼673 K with activation energies of 0.21 eV-0.40 eV. Above 673 K, the formation of oxygen vacancies results in a decrease in p-type carrier concentration and a decrease in electronic conductivity. Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3−δ (BSCF5582) was also measured under 10 −5 atm≤pO 2 ≤1 atm. Below ∼673 K, the electronic conductivity of BSCF 5582 shows no dependence on pO 2 . Above 673 K, the conductivity of BSCF5582 increases with increasing pO 2 for pO 2 ≥0.01 (p-type conduction) and decreases slightly with increasing pO 2 for pO 2 ≤0.01 atm. The activation energy for conduction above ∼673 K and at pO 2 ≥0.1 is ∼0.07 eV. Above ∼823K and at pO 2 ≥0.01 atm, the activation energy for conduction is ∼0.2 eV.

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“…Oxygen uptake and release were measured during heating from room temperature to 800 • C by a micro-thermo balance [4]. The ceramic samples were suspended by a platinum wire attached to a quartz spring and placed in the heating zone.…”

Section: Methodsmentioning

confidence: 99%

“…Different compositions with lanthanides, Sr, Ca, Ba on the A-site and with Mn, Fe, Co, Ni on the B-site have been proposed and investigated [1][2][3][4]. Oxide ceramic materials for high-temperature applications should satisfy a number of requirements, including high oxygen transport, chemical and structural integrity, suitable thermomechanical properties within a wide range of temperature and oxygen partial pressure.…”

Section: Introductionmentioning

confidence: 99%