FLOW PROPERTIES OF AQUEOUS PEROVSKITE-TYPE OXIDE LA0.6SR0.4COO3 SUSPENSION

The perovskite-type oxide La0.6Sr0.4CoO3(LSCO) is noted as a material for electrodes or catalysts. In order to form LSCO powder into a green product using colloid processing such as slip casting, tape casting, extrusion moulding, etc., aqueous LSCO suspensions were prepared and t heir flow properties were investigated in comparison with those of aqu eous YSZ (yttria-stabilized-zirconia) suspensions in this study. The a queous LSCO suspensions were prepared with LSCO powder synthesized fro m acetates, ammonium polyacrylate as the deflocculant, and distilled w ater. The viscosity of the LSCO suspensions system was so similar to t hat of YSZ system, i.e., a minimum value was obtained in the relations hip between viscosity and deflocculant concentration. The Bingham yiel d stress of the LSCO suspensions increased with aging time. It was fou nd that the amount of Sr ions leached from LSCO powder increased with aging time, too. Consequently, it was revealed that the flow propertie s are remarkably influenced by the concentration of leached Sr ions. I n addition, it was suggested that washing process of LSCO powder is ef fective in depressing the change of flow properties with aging time of aqueous LSCO suspension. (C) 1998 Elsevier Science B.V. All rights re served.