Sintering and stability issues of yttrium and ytterbium co-doped barium zirconium cerium oxide, BaZr0-1 Ce0.7Y0.1 Yb0.1O3-6 (BZCYYb), powders and electrolyte disks were investigated under conditions relevant to solid oxide fuel cell (SOFC) fabrication and operation. Conventional solid-state reaction method was used to synthesize BZCYYb powder. Effects of sintering temperature and BZCYYb contact with alumina (Al2O3) crucible during sintering were studied in details. Chemical stability was also studied by exposing the BZCYYb powder and disk to pure CO2 as well as 100 ppm H2S contaminated atmospheres. XRD, SEM, and TGA-DSC analysis were performed to characterize the BZCYYb powders and disks. Results showed BZCYYb material reacts significantly with alumina crucible during high temperature (> ∼1450 °C sintering, causing disintegration of perovskite structure and formation of doped cerium oxide on the side of the BZCYYb disk in direct contact with alumina crucible. By using a protective layer of BZCYYb powder, reaction of BZCYYb disks with the alumina crucible can be moderated. In addition, some weight loss was observed for BZCYYb disk during sintering process at above ∼1400 °C, which was attributed to BaO loss to the atmosphere and the alumina substrate. The amount of weight-loss is higher if the sintering temperature is higher or if the disk was sintered without protective powder cover layer. Results also showed BZCYYb is not chemically stable under pure CO2 as well as 100 ppm H2S contaminated atmospheres at typical fuel cell operating temperature of 750 °C, while good stability was observed at 450 °C in both atmospheres.
