Enhanced sintering and conductivity study of cobalt or nickel doped solid solution of barium cerate and zirconate

BaZr(0.9 − x)CexY(0.1 − y)CoyO(3 − δ) (with x = 0 and 0.2; y = 0.01; 0.02; 0.05) and BaZr(0.9 − x)CexY(0.1 − y)NiyO(3 − δ) (with x = 0 and 0.2; y = 0.01; 0.02) compounds have been synthesized by solid state reaction at 1400 °C and obtained as dense pellets after sintering at 1450 °C. Cobalt or nickel doping reduces the sintering temperature by about 250 °C.

The samples are stable in a CO2 rich atmosphere at 600 °C but the 5% B site Co doped samples are aging in wet atmosphere. The conductivity has been measured for the 1 and 2% doped samples (both cobalt and nickel), in different wet atmospheres and compared to the undoped compounds. The ionic and p-type conductivities have been determined, as well as the activation energy in wet reducing atmospheres, in which protonic conduction is dominant.

A decrease of the ionic conductivity is noticeable for the cobalt or nickel doped barium zirconate (x = 0), while not for cobalt or nickel solid solution of barium cerate and zirconate (x = 0.2).