Characterisation of BaZr_0.9Y_0.1O_3-δ prepared by three different synthesis methods: Study of the sinterability and the conductivity

BaZr_0.9Y_0.1O_3-δ has been synthesised by three different methods: the solid-state reaction, the spray pyrolysis and the spray drying. Significantly different apparent lattice parameters (between 0.4192 nm for the sample prepared by the solid-state reaction method and sintered at 1,500 °C and 0.4206 nm for the sample prepared by the solid-state reaction method and sintered at 1,720 °C) are observed after calcination and sintering, depending on the synthesis method and the sintering temperature. The bulk conductivity values also vary over several orders of magnitude (-7.2> log rb >-3.6 at 300 °C) depending on the synthesis method and the sintering temperature. These variations of the bulk conductivity and also the activation energy are correlated with variations of the apparent lattice parameter. The influence of the preparation method on the electrical properties is discussed. The grain boundaries are more resistive than the bulk. The variation of the grain boundary conductivity could be correlated to the microstructure in terms of the grain size.