The influence of the sintering temperature on BaZr0·7Ce0·2Y0·1O3-δ proton conductors prepared by Spark Plasma Sintering

Abstract BaZr0.7Ce0.2Y0.1O3-δ (BZCY72) proton-conducting ceramics were prepared by Spark Plasma Sintering. The effect of the sintering temperature (1150-1650°C) on the microstructural, crystallographic, and electrochemical properties of BZCY72 as well as long-term stability was investigated. From X-ray diffraction, rhombohedral BZCY72 was observed at all sintering temperatures. Specimen with the highest relative densities of around 99.5 % were obtained at 1450°C, also exhibiting high stability in ambient laboratory air over a period of six months. Total conductivities of 1.01 ×10-3 S∙cm-1 were obtained at 600°C in moist 5%H2/Ar. With increasing temperature the samples were denser, exhibited larger crystallite and grain sizes and consequently higher GB conductivities. A small increase in bulk conductivity was discussed in terms of decrease of degree of octahedra tilting and increase of B-O bond lengths.