Properties of Electrical Conductivity in Y-Doped CaZrO₃

Abstract

To clarify the high temperature electrochemical properties of Y-doped CaZrO₃, the electrical conductivity of the poly-crystalline specimen was measured for various kinds of hydrogen and oxygen-containing atmospheres by employing the two-terminal AC method. The H/D isotope effect of the electrical conductivity was examined in detail in order to specify the conditions in which the proton conduction was dominant. In the temperature range from 973 to 1273 K, it was found that protons are the dominant charge carrier both in hydrogen-rich and oxygen-rich atmospheres. At higher temperatures of 1373 to 1673 K, the dominant charge carrier is estimated to be the positive hole in oxygen-rich atmospheres, whereas to be the oxide ion vacancy in hydrogen-rich atmospheres by the analysis of the atmospheric dependence of the electrical conductivity. These results were almost the same as those of Al-doped CaZrO₃ which were reported previously by the present authors.