TAPE CASTING OF ZIRCONIA FOR ION CONDUCTING MEMBRANES - A STUDY OF DISPERSANTS

Powders of fully yttria stabilized zirconium oxide have been studied i n order to identify efficient dispersants for zirconia in tape casting slurries, and to verify that they do not impair the oxygen ion conduc tivity of the final-membrane. Of eleven screened dispersants, only thr ee were shown to be efficient. Sintered plates prepared with these dis persants had high and about equal oxygen ion conductivity (0.16-0.19 S cm-1 at 1000-degrees-C). The use of a phosphate ester as dispersant, possibly leaving traces of phosphorus in the sintered plate, did not i mpair the oxygen ion conductivity. Fish oils, common dispersants for t ape casting slurries, were not efficient for zirconia in the solvent s ystem that was studied. The addition of binder and plasticizers to the dispersions to form tape casting slurries did not cause reagglomerati on.