Rheophysical study of dispersed alumina suspensions

This paper studies the rheological behavior of aqueous suspensions of fine grained (d(50) = 200 nm) alumina. Rheological measurements were performed on suspensions containing various amounts of solid and 0.26 wt% of ammonium polymethacrylate in order to ensure a good state of dispersion. Brownian motions, colloidal interactions and hydrodynamic interactions dictate the behavior. The viscosity is mainly influenced by the shear rate and by the solid volume fraction. A Maron and Pierce model was used to describe this last effect in the hydrodynamic regime. The maximum packing fraction was found to be 40 vol%. This value is related to the colloidal stability as described by the DLVO theory. In fact, the maximum packing fraction leads to a surface-to-surface separation distance of about 46 nm because of the repulsive potential. Finally, a dimensionless approach was achieved to quantitatively identify, on the rheogram, the different flow regimes associated to each dominant interaction type. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

This paper investigates the rheological behavior of aqueous suspensions of fine grained alumina. The viscosity is mainly influenced by the shear rate and solid volume fraction. The maximum packing fraction is related to colloidal stability.