A pyrochlore-related Ce2Zr2O8-x phase was prepared, via a reduction re-oxidation process, from Ce0.5Zr0.5O2 powders. The Ce2Zr2O8-x, based upon cubic symmetry with a = 1.053nm, decomposed in N at 800C, but remained stable up to 900C in air. It exhibited mixed O ionic and electronic conductivity. The bulk conductivity at 700C was found to be 4 x 10-4S/cm in air and 10-2S/cm in N, and the activation energy was 1.27eV in air. The Arrhenius law was not obeyed in N, and a curved plot was observed from 400 to 700C. The conductivity then decreased rapidly, due to the thermal decomposition of Ce2Zr2O8-x.

Preparation and Electrical Properties of a Pyrochlore-Related Ce2Zr2O8-x Phase. H.Zhao, N.Guillet, F.Valdivieso, M.Pijolat: Solid State Ionics, 2003, 160[3-4], 317-26