Table 1 Composition of the four materials phases in the CGO-CFO MIEC system and their crystalline structure.

From: Three-dimensional imaging of grain boundaries via quantitative fluorescence X-ray tomography analysis

Material phase

Volume fraction

Composition ranges

Mean Composition

Crystalline Structure

CFO

34%

Ce0.03 Gd1.51–4x Co3x Fe1.44+x O4.52–1.5x

Ce0.03 Gd0.23 Co0.97 Fe1.76 O4.03

CoFe2O4, spinel

  

(0.275 < x < 0.373)

  

CGO

51%

Ce0.88–3x Gd0.12 Cox Fe2x O1.94–2x

Ce0.57 Gd0.12 Co0.10 Fe0.2 O1.74

CeO2, cubic F-type

  

(0 < x < 0.19)

  

EP1

2%

Ce0.78–3x Gd1.22–3x Co2x Fe4x O3.39–2.5x

Ce0.47 Gd0.90 Co0.21 Fe0.42 O3.13

Gd2O3 cubic C-type

  

(0.05 < x < 0.16)

  

EP2

13%

Ce0.60 −3x Gd0.82–2x Co2x Fe0.56+3x O3.3–2.5x

Ce0.33 Gd0.64 Co0.18 Fe0.83 O3.05

GdFeO3 orthorhombic

  

(0.02 < x < 0.16)

  
  1. The volume fraction of each phase is determined by the segmentation of the volumetric tomography dataset. The quintenary compositions defined in the text (CewGdxCoyFez with w + x + y + z=1) are converted into the conventional bulk compositions based on the crystalline structure of these material phases. The mean composition is taken at the middle of the composition range. The oxygen stoichiometry is estimated by assuming the oxidation states: Ce = 4, Gd = 3, Fe = 3, and Co = 2.
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