Prediction and evaluation of sintering aids for Cerium Gadolinium Oxide

This paper presents dilatometry results for Ce0.9Gd0.1O1.95, a common intermediate temperature solid oxide fuel cell electrolyte material, doped at the 1, 3, and 5 mol% level using nitrates. The results indicate that across all dopant nitrate levels, Cu, Co, Fe, Mn, Li, and Zn reduce the Ce0.9Gd0.1O1.95 sintering temperature, while Ca, Mg, and Ni have little effect, and Al and K increase the sintering temperature. These results can be interpreted in terms of a Vegard's Slope quality factor analysis which uses a dopant's charge and size to rank its propensity to heterogeneous dope the material and/or segregate to the grain boundary as a separate phase. Further, this work shows that Ce0.9Gd0.1O1.95 can be sintered to 99% density at a record-low temperature of 800 °C, using as little as 3 mol% lithium as a dopant.