Characterization of YSZ electrolyte membrane tubes prepared by a vacuum casting method

Eight mol% YSZ electrolyte membrane tubes with a thickness of 0.2 mm were made using a vacuum casting method. The sintered densities, microstructure and electrical conductivity of the YSZ electrolyte membrane tubes were studied using the Archimedes water immersion technique, SEM and complex impedance, respectively. The sintering temperature corresponding to optimal sinterability for the YSZ electrolyte membrane tubes was determined. The research results show that vacuum casting is a simple way of preparing YSZ electrolyte membrane tubes with high density and high electrical conductivity. YSZ electrolyte membrane tubes with a relative density of 98.1% and 254 mm in length are fabricated using this method. The range of sintering temperatures is 190-200°C lower than that of the conventional slip casting. The densification and the electrical conductivity of the samples increase gradually with the increase of the sintering temperature. The density and electrical conductivity of the samples reach an optimum value at a sintered temperature of 1600°C for 2 h. As the sintering temperatures are raised further, both the density and the electrical conductivity of the samples decrease.