Redox processes in highly yttrium-doped barium titanate

The changes of microstructure occurring during oxidation of the reduced form of yttrium-doped barium titanate image have been studied. Samples were sintered under reduction conditions at image and oxidized by annealing at high temperatures (1150 and 1350 °C) in air. Depending on yttrium concentration, the oxidation of the reduced form of the yttrium-doped BaTiO3 caused precipitation of the phase Ba6Ti17O40 or the phases Ba6Ti17O40 and Y2Ti2O7. The precipitates had well-defined orientational relationships with the perovskite matrix. Oxidation of the reduced form of doped barium titanate results in formation of the phase image responsible for increase in the resistance of outer grain layers, which lie between grain boundaries and grain.