Phase Stability and Electrical Conductivity in Gd2Ti2O7-Gd2Mo2O7 Solid Solutions |
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| Authors: | Ofer Porat Catherine Heremans Harry L Tuller |
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| Affiliation: | Crystal Physics and Electroceramics Laboratory, Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 |
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| Abstract: | Solid solutions in the Gd2(Ti1-yMoy)2O7 pyrochlore system, with y = 0.1, 0.3, 0.5, and 0.7, have been investigated as potential candidates for the anode material of solid-oxide fuel cells. The electrical conductivity, stability range, and optimal synthesis conditions of the pyrochlore phase have been explored by electrical, coulometric titration, and X-ray diffractometry techniques. As the molybdenum content increases, the maximum conductivity increases to a value of 70 S/cm for y = 0.7 at 1000°C, whereas the stability range in the oxygen partial pressure (pO2) decreases to just over two orders of magnitude in pO2 in the temperature range of 600°-1000°C. A decomposition reaction that leads to decreased conductivity in oxidizing atmospheres is proposed. |
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