Abstract: 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 rates γ_c (the onset of shear thickening) dependence on the particle size was quantified
with a simple shear model.

Key words: Al₂O₃ suspension, tri-ammonium citrate, rheological behavior, cluster-forming barrier