Effect of slurry properties on anode cermets for solid oxide fuel cells

The influence of the initial slurry properties on the resulting Ni-YSZ (yttria-stabilized zirconia) cermet structure that constitutes the solid oxide fuel cell anode has been examined. Rheological study of the slurry has been conducted as a function of powder concentration. The powder consisted of Ni (80 wt.%) and YSZ (20 wt.%) particles, and the slurry was prepared by mixing the powders in polyvinyl alcohol (PVA) solution. This suspension was shown to be pseudoplastic without a yield point and a model based on the Ostwald-de Waele power law has been developed. Porous structures resulting from slurry coating, sintering and infiltration were examined utilizing microprobe, scanning electron microscopy (SEM) and X-ray techniques. The resulting structure was shown to be inadequate when the slurry suspensions contained less than 12 or more than 13 vol.% of the powders.