In this study, the electrorheological (ER) behavior of suspensions prepared from d(50) = 7 mu m kaolin particulate, dispersed in insulating silicone oil (SO) medium, was investigated. ER activity of all the suspensions was observed to increase with increasing electric field strength (E), concentration (c), and decreasing shear rate (gamma). Shear stress (gamma) of kaolin suspensions increased linearly with increasing concentrations of the particles and with the applied electric field strength. The viscosity (eta) of all suspensions was decreased sharply with increasing shear rate and showing a typical shear thinning non-Newtonian viscoelastic behavior. It was observed that kaolin/silicone oil system studied in the present work was sensitive to high temperature. (c) 2006 Wiley Periodicals, Inc.