Preparation of Nd-doped barium cerate through different routes

Abstract

BaCe 0.9Nd 0.1O 3 − δ was prepared through different routes: oxalate coprecipitation (OP), carbonate-oxide mixed by ball-milling (COB) and carbonate-oxide mixed by mortar/pestle (COM). The reaction process studied by DTA-TG and XRD showed that calcination of the precursor powders at T ≥ 1000 °C could produce a single perovskite phase for all the three routes. The densification process studied by constant heating rate dilatometry revealed that the shrinkage behaviours for OP and COB were quite similar, but they differed significantly from that for COM. The sintered density and open porosity indicated that the calcination temperature had a major influence on the sintering process for all the three routes. The calcined powders from OP and COB had small particle size, large surface area and good sinterability, while those from COM had large particle size, small surface area and poor sinterability. Nearly dense materials could be obtained at a sintering temperature of 1400 °C from OP and at a sintering temperature as low as 1300 °C from COB. However, for samples from COM, even when sintered at 1500 °C, only porous microstructure could be obtained. Electrical measurements in hydrogen atmosphere showed that, at a given temperature, samples from OP had the highest conductivity, and the conductivity of the samples from COB was a little bit lower than that of the samples from OP, while samples from COM had the lowest conductivity.