Growth of ternary oxides in the Gd2O3–Fe2O3 system. A diffusion couple study

Buscaglia, Vincenzo; Buscaglia, María Teresa; Giordano, Livia; Martinelli, A.; Viviani, Massimo; Bottino, C.

doi:10.1016/s0167-2738(01)01021-9

Cited by 22 publications

(19 citation statements)

References 31 publications

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“…This suggests that Fe 2 O 3 may have been dissolved in LaFeO 3 through a solid state reaction working in parallel with gas phase transport. For similar diffusion couple experiments between Y 2 O 3 /Fe 2 O 3 [15] and Gd 2 O 3 /Fe 2 O 3 [16] it has been demonstrated that gas phase transport of iron is an important transport mechanism at the product phase/Fe 2 O 3 interface.…”

Section: Methodsmentioning

confidence: 81%

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Cation self-diffusion in LaFeO3 measured by the solid state reaction method

Smith

Norby

2006

Solid State Ionics

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Section: Methodsmentioning

confidence: 81%

“…The technique based on the solid state reaction has also been used to determine the cation diffusion in GdFeO 3 [16], LaCrO 3 [14], YCrO 3 [24] and BaTiO 3 [25]. While GdFeO 3 showed predominant B-site diffusion, the three others had the growth kinetics controlled by A-site diffusion.…”

Section: Discussionmentioning

confidence: 99%

Cation self-diffusion in LaFeO3 measured by the solid state reaction method

Smith

Norby

2006

Solid State Ionics

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“…The STEM-EDX quantification results also revealed that the GFCCO phases were rich in Gd and Fe. Simultaneous growth of GdFeO 3 (perovskite) and Gd 3 Fe 5 O 12 (garnet) was observed in Gd 2 O 3 –Fe 2 O 3 diffusion couples at 1,200–1,400 °C with activation energies of ∼400 and ∼550 kJ mol −1 , respectively44. Among the potential GFCCO phases, GdFeO 3 is thermodynamically more favoured to form than Gd 3 Fe 5 O 12 .…”

Section: Resultsmentioning

confidence: 96%

Enhancing grain boundary ionic conductivity in mixed ionic–electronic conductors

et al. 2015

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Mixed ionic–electronic conductors are widely used in devices for energy conversion and storage. Grain boundaries in these materials have nanoscale spatial dimensions, which can generate substantial resistance to ionic transport due to dopant segregation. Here, we report the concept of targeted phase formation in a Ce0.8Gd0.2O2−δ–CoFe2O4 composite that serves to enhance the grain boundary ionic conductivity. Using transmission electron microscopy and spectroscopy approaches, we probe the grain boundary charge distribution and chemical environments altered by the phase reaction between the two constituents. The formation of an emergent phase successfully avoids segregation of the Gd dopant and depletion of oxygen vacancies at the Ce0.8Gd0.2O2−δ–Ce0.8Gd0.2O2−δ grain boundary. This results in superior grain boundary ionic conductivity as demonstrated by the enhanced oxygen permeation flux. This work illustrates the control of mesoscale level transport properties in mixed ionic–electronic conductor composites through processing induced modifications of the grain boundary defect distribution.

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“…Gas-phase transport can occur by direct vaporization of the oxides or by formation of gaseous hydroxides, as observed in the systems MgO-Al 2 O 3 , 25 NiO-Al 2 O 3 , 26 ZnO-Al 2 O 3 27 and Gd 2 O 3 -Fe 2 O 3 . 28 The formation of gaseous Ba(OH) 2 was previously proposed by Ubaldini et al 29 to explain the more rapid formation of BaZrO 3 in humid air atmosphere than in dry air atmosphere. The volatility of alkaline-earth monoxides is greatly increased by the presence of water vapor because of the forma- tion of volatile hydroxide vapors given as follows:…”

Section: Effect Of Water Vapor On the Formation Of Mtiomentioning

confidence: 88%

“…In accordance with the Refs. [28,29], a rough estimate of the mass flux of barium, J g , through the gas-phase can be obtained by means of Fick's law as follows:…”

Section: Effect Of Water Vapor On the Formation Of Mtiomentioning

confidence: 99%