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Schlagwörter:
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Zusammenfassung:
Electrical conductivities of Gd-doped (0.15 mol %) and
nominally pure nanocrystalline CeO2-x ceramics (similar to30 nm
grain size) were measured by impedance spectroscopy in the
temperature range of 673-773 K under various oxygen partial
pressures (1-10(5) Pa). The ionic and electronic contributions
were separated using electrochemical polarization with an
electronically blocking electrode, yttria-stabilized zirconia.
The results allow for a clear distinction between potential
explanations. It is shown that the space charge model (space
charge zones with potential of similar to0.3 V resulting in
depletion of oxygen vacancies and accumulation of conduction
electrons) explains all the experimental features. (C) 2002 The
Electrochemical Society.
