Oxygen ionic conduction in brownmillerite CaAl0.5Fe0.5O2.5+

Хартон, В.В.; Marozau, Ivan; Vyshatko, N. P.; Shaula, A.L.; Viskup, A.P.; Naumovich, E.N.; Marques, F.M.B.

doi:10.1016/s0025-5408(03)00069-2

Cited by 39 publications

(20 citation statements)

References 22 publications

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“…The oxygen ionic conductivity under oxidising conditions was estimated from the data on total conductivity and oxygen permeability, as described elsewhere. 6,[17][18][19] All data on oxygen permeation presented in this work correspond to the membrane feed-side oxygen partial pressure (p 2 ) fixed at 0.21 atm (atmospheric air).…”

Section: Methodsmentioning

confidence: 99%

“…Indeed, XRD analysis of samples quenched from 800-950 • C showed no essential changes in the phase composition, in agreement with data on CaFe 0.5 Al 0.5 O 2.5+δ . 17 Such a behaviour might be advantageous for membrane applications, although further studies are necessary in order to reveal contributions of the constituent phases to total expansion of the ceramic materials.…”

Section: Thermal Expansionmentioning

confidence: 99%

“…The data on SrFeO 3−δ and CaFe 0.5 Al 0.5 O 2.5+δ , used in this work for comparison, were partly published elsewhere. [15][16][17] …”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Oxygen ionic transport in SrFe1−yAlyO3−δ and Sr1−xCaxFe0.5Al0.5O3−δ ceramics

Shaula

Хартон

Vyshatko

et al. 2005

Journal of the European Ceramic Society

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Section: Methodsmentioning

confidence: 99%

Section: Thermal Expansionmentioning

confidence: 99%

See 1 more Smart Citation

Oxygen ionic transport in SrFe1−yAlyO3−δ and Sr1−xCaxFe0.5Al0.5O3−δ ceramics

Shaula

Хартон

Vyshatko

et al. 2005

Journal of the European Ceramic Society

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“…In general, this type of improvement should mostly enhance the ionic conductivity, as the electronic conductivity is usually less sensitive to such microstructural features. In fact, the presence of ionblocking grain boundaries usually provides underestimated ionic transport numbers (14).…”

Section: Resultsmentioning

confidence: 99%

Conducción iónica del oxígeno en óxidos: mecanismos básicos y algunos ejemplos

Traqueia¹,

Marques²,

Хартон³

2006

Bol. Soc. Esp. Ceram. Vidr.

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Oxygen ion conductors with most symmetrical structures such as fluorite-and perovskite-related phases, rely on the mobility of oxygen vacancies. High-performance electrolytes, namely with the apatite type structure, recently developed, show dominant interstitial transport. In order to assess basic composition-conductivity relationships in a fluorite-derived C-type cubic structure with high tolerance to different types of oxygen defects, a series of Y 2 O 3 -based materials were studied by impedance spectroscopy in air in the range 700-1000 o C. Yttria doped with CaO exhibits reasonably high ionic conduction via the vacancy mechanism. Samples doped with ZrO 2 and HfO 2 possess oxygen interstitials as dominant defects, but show poor ionic conductivity when compared to Ca-doped materials. These tendencies, known for other fluorite-related phases such as pyrochlores, are opposite to those observed for apatite-and K 2 NiF 4 -type structures. Comparison of ionic conductivity levels in various oxide materials suggests that fast interstitial migration may be expected for complex multicomponent materials where the ion transport occurs in lattice fragments with high bond ionicity. Furthermore, conduction-affecting stereological parameters, to a great extent, depend on the relaxation of covalent fragments.Keywords: oxygen ion conductors, defect mobility, C-type cubic structure, yttria, apatite. Conducción iónica del oxígeno en óxidos: mecanismos básicos y algunos ejemplos.Los conductores iónicos de oxígeno con estructuras más simétricas como fluorita y perovsquita dependen de la movilidad de las vacantes de oxígeno. Se han desarrollado recientemente electrolitos con elevadas prestaciones, los llamados de estructura tipo apatito, que muestran transporte intersticial dominante. Con el objeto de establecer las relaciones básicas entre composición y conductividad en una estructura cúbica tipo-C derivada de la fluorita con alta tolerancia a diferentes defectos de oxígeno, se han estudiado materiales basados en Y 2 O 3 por espectroscopía de impedancia en el rango de temperaturas entre 700 y 1000ºC. La ytria dopada con CaO exhibe una conductividad iónica razonablemente alta vía mecanismo de vacantes. Las muestras dopadas con ZrO 2 y HfO 2 poseen oxígenos intersticiales como defectos dominantes pero presentan una conductividad iónica poble comparada con los materiales dopados con CaO. Estas tendencias, conocidas para otras fases relacionadas con la estructura fluorita como los pirocloros, son opuestas a las que se observan en estructura de tipo apatito y K 2 NiF 4 . La comparación de los niveles de conduccion iónica entre varios materiales oxídicos apunta a la existencia de un mecanismo rápido de migración intersticial. Este mecanismo cabría expresarse en materiales multicomponente complejos en los que el transporte iónico tiene lugar en partes de la red con elevada ionicidad del enlace. Más aún, los parámetros estereológicos que afectan a la conducción, en gran medida dependen de la relajación de las partes covalentes.Palabras cl...

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“…Oxide ion conduction in the Brownmillerite structure type has been studied since 1990, when Goodenough et al [28] reported an order-disorder transformation in Ba 2 In 2 O 5 leading to fast ion conduction above ∼925 • C. Ba 2 In 2 O 5 and its analogs have since been the subject of many studies linking the structures to the temperature dependence of the conductivity and behavior in the presence of water, CO 2 , and under reducing conditions. (see for example [29][30][31][32][33]) Figure 8 shows the in-situ XRD data for Ba 2 In 2 O 5 up to 1105 • C, in which the orthorhombic to tetragonal to cubic phase transformations are obvious. Although the XRD method is insensitive to the oxygen sublattice, the in-situ XRD measurements show the phase transformations clearly, and unambiguously provide the time dependence of the phase transformations.…”

Section: Applications In Electroceramicsmentioning

confidence: 99%

In situ X-ray diffraction studies of electroceramics

Misture

2006

J Electroceram

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In-situ high temperature powder X-ray diffraction is in the midst of a renaissance enabled by new X-ray optics, detectors, computational methods, and furnace designs. In-situ diffraction, under controlled temperature, atmosphere, pressure, electric and magnetic field, etc. has enabled many studies of materials systems that are not easily studied using the more traditional quenching methods. A brief overview of the current capabilities of high temperature diffraction in the laboratory is presented. Examples center on ionic and electronic conductors and capabilities for controlling temperature and oxygen partial pressure that are so often critical in the study of electroceramics.

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Oxygen ionic conduction in brownmillerite CaAl0.5Fe0.5O2.5+

Cited by 39 publications

References 22 publications

Oxygen ionic transport in SrFe1−yAlyO3−δ and Sr1−xCaxFe0.5Al0.5O3−δ ceramics

Oxygen ionic transport in SrFe1−yAlyO3−δ and Sr1−xCaxFe0.5Al0.5O3−δ ceramics

Conducción iónica del oxígeno en óxidos: mecanismos básicos y algunos ejemplos

In situ X-ray diffraction studies of electroceramics

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