Electronic conduction mechanism in yttria-stabilized zirconia-titania under reducing atmospheres
- Univ. of Pennsylvania, Philadelphia, PA (United States). Dept. of Materials Science and Engineering
Yttria [12 mole percent (m/o)] stabilized zirconia with 5 to 10 m/o titania (YZTi) exhibits oxygen-ion and n-type conductivity under reducing atmospheres at elevated temperatures. Electron paramagnetic resonance (EPR) measurements reveal that the Ti{sup 3+} concentration of YZTi increases with increasing temperature, increasing TiO{sub 2} content, and decreasing oxygen pressures below 10{sup {minus}10} atm at 830 C. Impedance measurements show that the total electrical (oxygen-ion plus n-type) conductivity of YZTi having 10 m/o TiO{sub 2} follows the same behavior and increases at oxygen pressures below 10{sup {minus}15} atm at 838 C. The EPR and impedance results support an electron hopping mechanism between the 3{sup +} and 4{sup +} oxidation states of titanium. Modeling of the impedance data verifies that the n-type conductivity occurs in the YZTi lattice and is not restricted to the grain boundaries. A percolation model shows that electron hopping can occur in YZTi when titanium ions occupy as few as 3 to 4% of the cation sites.
- Sponsoring Organization:
- National Science Foundation, Washington, DC (United States); Gas Research Inst., Chicago, IL (United States)
- OSTI ID:
- 428176
- Journal Information:
- Journal of the Electrochemical Society, Vol. 143, Issue 11; Other Information: PBD: Nov 1996
- Country of Publication:
- United States
- Language:
- English
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