Rheological behavior of TiO2/water suspensions

The rheological properties of TiO2/water suspensions were examined by means of Brabender rheometer with rheological method. It was observed that yield stress and steady shear viscosity of TiO2/water suspensions with narrow PSD is higher than those of TiO2/water suspensions with wide PSD. When volume fraction of particle Phi is very low, the suspension exhibits Newtonian behavior. All tested pastes exhibit shear-thinning behavior when volume fraction of particle Phi is higher than a certain value; when Phi beyond a critical value, the pastes have yield stress and exhibit more obvious shear-thinning behavior. The shear viscosity of TiO2/water suspensions follows a generalized Quemada model and parameters were obtained by simulating. When the temperature is below 40 degrees C, the shear viscosity and yield stress decrease with the increasing of temperature; when the temperature is higher than 40 degrees C, yield stress increases with the increasing of temperature while shear viscosity exhibits complex behavior. The temperature dependence of shear viscosity and yield stress can be explained by collision theory of fine particles in suspending mediums.