Electrical Properties of Beryllium-Doped Gd2Zr2O7

— Dense Gd 2 Zr 2 O 7 -based ceramics with the composition Gd 2 Zr 1.9 Be 0.1 O 6.9 , containing heterovalently substituted beryllium on the zirconium site, have been prepared for the first time via mechanical activation of an oxide mixture, followed by annealing of green compacts at 1500°C. The use of mechanical activation has been shown to enable the preparation of dense ceramics (relative density of 88%) by annealing for 5 min and gas-tight ceramics (relative density of 97.3%) by annealing for 4 h. Gd 2 Zr 1.9 Be 0.1 O 6.9 has a pure oxygen ion conductivity of 4.0 × 10 –3 S/cm at 800°C. The main advantage of partial beryllium substitution on the zirconium site in Gd 2 Zr 2 O 7 is the formation of a material having negligible electron and hole conductivities in wide ranges of oxygen partial pressures and temperatures.