Rheological Behavior of Modified Starch-Alumina Oxide Suspensions

A modified starch was employed to be the pore former in the in-situ consolidation forming process of porous alumina ceramic. In order to prepare ceramic slurry with high dispersion, high stabilization and high solid volume loading, the effects of modified starch content, dispersant content, alumina solid volume loading, pH value of the slurry and ball milling time on the rheological behavior of alumina ceramic slurry were investigated. The results indicated that the viscosity of the slurry increased with the modified starch content, alumina solid volume loading and ball milling time. When the pH value of the slurry was 9.0, the modified starch-alumina slurry exhibited high fluidity. The modified starch-alumina slurry was a pseudoplastic fluid exhibiting shear thinning behavior. The slurry possessed a desirable plasticity to enable shape forming when adding 50 vol% modified starch and 1.0 wt% dispersant to the alumina slurry at pH 9.0 after 14 h ball milling treatment.