| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1605149 | Journal of Alloys and Compounds | 2016 | 9 Pages |
•Th1-xYxO2-x/2 ceramics were successfully prepared from oxalate precursors.•Precursors and final oxides were extensively characterized.•Sintering conditions to achieve complete densification of the samples were investigated.•First evaluation of the electrical conductivity was undertaken by impedance spectroscopy.
The preparation of Th1-xYxO2-x/2 ceramics, to be used as electrolyte in oxygen sensors for sodium-cooled nuclear reactors, was successfully undertaken from oxalate precursors. Such method was found to provide quantitative precipitation of the cations into (Th,Y)(C2O4)2·2H2O solid solutions up to x = 0.15 while a polyphase system was obtained for x = 0.22. The corresponding oxides were obtained through heat treatment in air at 500 °C and characterized by the means of PXRD, SEM and statistical X-EDS measurements. The conditions for the densification of Th1-xYxO2-x/2 ceramics were further determined by dilatometry (T = 1575 °C, t = 8 h) resulting in densification rates up to 99%. Finally, a first estimation of the electrical properties of the solids was undertaken by impedance spectroscopy. Electrical conductivity was found to increase linearly with the incorporation of Y3+ content while the associated values of activation energy decreased, with a minimum value of 1.1 eV for Th0.85Y0.15O1.925.
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