Understanding the rapid reoxidation process and the electrical properties of Spark Plasma sintered pyrochlores

Pyrochlore structures with composition Pr2−xSmxZr2O7 (x = 0, 1, and 2) were synthetized and studied. Spark Plasma Sintering (SPS) was employed to produce ceramics with over 95% of relative density. The reoxidation behavior and the influence of the sintering process on the electrical properties were studied by Electrochemical Impedance Spectroscopy. The overall conductivity of the materials is higher for the samples with Pr, while the introduction of Sm induced an additional electrical contribution. The reoxidation of the samples presented fast kinetics and increased conductivity, particularly in the PrSmZr2O7 (PSZO) sample. PSZO also exhibits a total conductivity comparable to that of the reference materials used as ionically conductive solid electrolytes. The prepared ceramics, especially the PSZO sample, demonstrate excellent relative density, good conductivity, and fast oxidation, holding promise for applications such as Solid Oxide Fuel Cells, gas sensors, and clean energy technologies that require thermal and physical stability, as well as rapid oxidation-reduction processes.