Rheological Behavior of Alumina Suspensions

The effect of various contents of dispersant on the rheological behavior of alumina suspensions stabilized with TAC (Tri-Ammonium Citrate) was studied. Based on analyzing the interaction potential among particles in the suspensions, the rheological behavior of suspensions, such as shear thinning and shear thickening, was elucidated. It was considered that there exists particle clusters caused by the collision between particles due to Brownian motion in the static suspensions, and shear thinning is the result of decomposition of thermodynamic clusters while shear thickening is the result of formation of hydrodynamic clusters. The viscosity of alumina . suspensions at low and high shear rate is respectively determined by zeta and Stern potential near the particle surface, and shear thickening behavior can be suppressed with excess TAC amount. At the same time, the critical shear ratesγC (the onset of shear thickening) dependence on the particle size was quantified with a simple shear model.