Effects of Yb-Concentration on the Proton Conductivities of Low Temperature Sinterable Barium Zirconate Ceramics

Abstract

The 10~25 mol% Yb-doped BaZrO₃ ceramics having relative densities higher than 98% were obtained by the stoichiometric addition of 4 mol% ZnO as a sintering aid and then sintering at 1300°C for 10 hours. The crystal structure of the 10 mol% Yb-doped BaZrO₃ ceramics was monoclinic (space group: Pm), while the crystal structures of the 15~25 mol% Yb-doped BaZrO₃ ceramics were cubic (space group: Pm3m). When the crystal structures were cubic, the activation energy of the proton conductivities increased as the Yb-concentration increased. Due to the high activation energy, the proton conductivities of the 25 mol% Yb-doped BaZrO₃ ceramics were significantly lower than those of the 10~20 mol% Yb-doped BaZrO₃ ceramics, especially as the temperature decreased.