Electrical conductivity of polycrystalline 3Y2O3·WO3 at high temperatures

The electrical conductivity of polycrystalline Y₆WO₁₂ (3Y₂O₃·WO₃) and of polycrystalline Y₆WO₁₂ doped with alkaline earth oxides or ZrO₂ were measured over the temperature range from 800 to 1400°C under oxygen partial pressures of 10⁻⁵ to 10⁰ atmospheres. Y₆WO₁₂ showed a p-type conductivity at higher oxygen pressures and an n-type conductivity at lower oxygen pressures. Additions of alkaline earth oxides increased the conductivity of Y₆WO₁₂ in the higher oxygen pressure region. The conductivity of alkaline earth oxides-doped Y₆WO₁₂ decreased monotonically with decreasing oxygen partial pressures and approached constant values at lower oxygen partial pressures. The ZrO₂ addition caused a decrease in the conductivity of Y₆WO₁₂ in the higher oxygen pressure region. The variations of the conductivity with oxygen pressure are discussed assuming various defects models.