ABSTRACT
The system TiO2-Y2O3-ZrO2 was studied to establish the stability range of the tetragonal phase. The materials were prepared by the coprecipitation method in order to obtain fine, homogeneous and sinteractive powders. 1 - 30 mol%TiO2 was added systematically to 1, 2, 3 and 4 mol%Y2O3-doped ZrO2. The ionic conductivity of the ternary tetragonal ZrO2 was investigated using impedance spectroscopy at temperatures between 250 and 700 °C. The ionic conductivity decreases with increasing TiO2 content. Hole and electron transport properties as a function of temperature between 500 and 700 °C and oxygen partial pressure between 102 and 105 Pa using the Hebb-Wagner polarization technique show an increase of the electron conductivity with increasing TiO2 content whereas the hole conductivity remains unchanged. As in the case of undoped samples, the hole conductivity follows a 1/4 power law dependence on the oxygen partial pressure which indicates a large concentration of ionic defects.
