Measurements were made of the conductivity and transport numbers of ceramic samples in an O or water-vapor atmosphere. The appearance of proton conductivity in structures of perovskite type in proton-containing media at high temperatures was noted. It was found that, for all of the compositions which were investigated, the apparent H transport number decreased with increases in temperature or Nd content. Arrhenius plots of the temperature dependences of the total electrical conductivities were usually non-linear. As the temperature was decreased, the slope of the curves also decreased. The total electrical conductivity of BaCe0.9Nd0.1O3 in air at 900C was equal to 0.06S/cm. A decrease in the O partial pressure was accompanied by a decrease in the electrical conductivity. This implied the existence of hole conductivity. In a reducing atmosphere at 900C, a decrease in O activity caused an increase in the total electrical conductivity. However, this was attributed to an increase in ionic conductivity rather than to the appearance of electron conductivity. In this region, the conductivity was due only to ion transport. At temperatures below 800C, in a reducing atmosphere, the electrical conductivity was found to be independent of the O partial pressure. At 600C, the conductivity remained unchanged over the entire range of O partial pressures.

N.V.Arestova, V.P.Gorelov: Elektrokhimiya, 1994, 30[8], 988-90 (Russian Journal of Electrochemistry, 1994, 30[8], 892-4)