Different compositions in a solid solution of general formula Dy 2(Ti1-yZry)2O 7, showing high oxygen ion conductivity, have been successfully prepared at room temperature via mechanochemical synthesis. Stoichiometric mixtures of the constituent oxides were dry milled together in a planetary ball mill by using zirconia vials and balls. Chemical changes in the powder mixtures as a function of composition and milling time were followed by X-ray diffraction and revealed that, in all cases and after milling for 19 h, the powder mixtures consisted of a single phase. Electrical properties were measured on sintered pellets as a function of frequency, temperature and zirconium content, revealing an increase in conductivity of more than one order of magnitude for y≥0.4, which, as observed in the similar Y2(Ti1- yZry)2O7, has been related with the onset of disordering of the anion sublattice. Despite increasing structural disorder with increasing Zr content, conductivity remains almost constant for y>0.6, reaching a maximum value of ∼5×10-3 for Dy 2Zr2O7 at 900 °C.
Bibliographical noteFunding Information:
This work has been carried out with the financial assistance of CONACYT (SEP-2003-C02-44075) and CAM (GR/MAT/0250/2004). Helpful discussions with U. Amador are greatly appreciated.
- Dysprosium titanate-zirconate
- Ionic conduction
- Mechanochemical synthesis
- Phase transition