2010 年 57 巻 1 号 p. 8-11
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.