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The Thickness Dependence of Oxygen Permeability in Sol-Gel Derived Ce0.8Gd0.2O2-δ-CoFe2O4 Thin Films on Porous Ceramic Substrates: A Sputtered “Blocking Layer” for Thickness Control

Published online by Cambridge University Press:  01 February 2011

Kyle S. Brinkman
Affiliation:
[email protected], Savannah River National Laboratory (SRNL), Materials Science and Technology Directorate, Aiken, South Carolina, United States
Takashi Iijima
Affiliation:
[email protected], National Institute of Advanced Industrial Science and Technology (AIST), Research Center for Hydrogen Industrial Use and Strage, Tsukuba, Ibaraki, Japan
Hitoshi Takamura
Affiliation:
[email protected], Tohoku University, Department of Materials Science, Sendai, Japan
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Abstract

Mixed conductive oxides are a topic of interest for applications in oxygen separation membranes as well as use in producing hydrogen fuel through the partial oxidation of methane. The oxygen flux through the membranes is governed both by the oxygen ionic conductivity as well as the material's electronic conductivity; composite membranes like Ce0.8Gd0.2O2-δ(CGO)-CoFe2O4 (CFO) use gadolinium doped ceria oxides as the ionic conducting material combined with cobalt iron spinel which serves as the electronic conductor. In this study we employ ˜ 50 nm sputtered CeO2 layers on the surface of porous CGO ceramic substrates which serve as solution ‘blocking’ layers during the thin film fabrication process facilitating the control of film thickness. Films with thickness of ˜ 2 and 4 microns were prepared by depositing 40 and 95 separate sol-gel layers respectively. Oxygen flux measurements indicated that the permeation increased with decreasing membrane thickness; thin film membrane with thickness on the micron level showed flux values an order of magnitude greater (0.03μmol/cm2 s) at 800oC as compared to 1mm thick bulk ceramic membranes (0.003 μmol/cm2).

Type
Research Article
Copyright
Copyright © Materials Research Society 2009

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References

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