Compositions of (ZrO2)0.92(Y2O3)0.08 (zirconia: 8 mol % yttria???8YSZ) and (CeO2)0.8(Sm2O3)0.2 (ceria: 20 mol % samaria???SDC20) ceramic powders were prepared by attrition milling to form an equimolar powder mixture, followed by uniaxial and isostatic pressing. The pellets were quenched to room temperature from 1200 ??C, 1300 ??C, 1400 ??C and 1500 ??C to freeze the defects configuration attained at those temperatures. X-ray diffraction analyses, performed in all quenched pellets, show the evolution of the two (8YSZ and SDC20) cubic fluorite structural phases to a single phase at 1500 ??C, identified by Rietveld analysis as a tetragonal phase. Impedance spectroscopy analyses were carried out in pellets either quenched or slowly cooled from 1500 ??C. Heating the quenched pellets to 1000 ??C decreases the electrical resistivity while it increases in the slowly cooled pellets; the decrease is ascribed to annealing of defects created by lattice micro-tensions during quenching while the increase to partial destabilization of the tetragonal phase.Conselho Nacional de Desenvolvimento Cient??fico e Tecnol??gico (CNPq)Funda????o de Amparo ?? Pesquisa do Estado de S??o Paulo (FAPESP)CNPq: 470952/2013-0; 303483/2013-0; 311803/2015-6FAPESP: 13/07296-2