Rheological Characterization of Alumina Ceramic Suspensions in Presence of a Dispersant and a Binder

The rheological responses of aqueous alumina suspensions, stabilized with an organic polyvalent salt dispersant called “Aluminon,” and including a poly(vinyl) alcohol (PVA) binder, are described in this study. It is observed that the addition of PVA, without any dispersant does not significantly influence the rheology. However, in the presence of the dispersant the rheology is affected significantly. At a given concentration of the dispersant, the viscosity, the storage and loss modulii all increase with the PVA concentration. Also, for a given concentration of the PVA, the viscosity, the storage and loss modulii values increases as the concentration of the dispersant is increased. At relatively low PVA concentrations, an excess concentration of the dispersant, causes flocculation of the particles in the suspension by a reduction of the electrostatic (double layer) effect. On the contrary, at higher concentrations of the PVA the flocculation of the suspension occurs via a depletion mechanism.