Preparation and Rheology of Magnetorheological Fluid Using Six Kinds of Fumed Silica as Stabilizing Additives

Abstract

In this study, magnetorheological fluid (MRF) was prepared with several kinds of hydrophobic fumed silica in order to improve MRF stability while maintaining desirable fluidity. We conducted steady flow measurements and oil separation tests under gravity and centrifugal conditions. The linkage of fumed silica particles was also observed morphologically by transmission electron microscopy. We found that the MRF sedimentation stability correlated with viscosity in the lower shear rate range. The oil separation ratio improved with the addition of the fumed silicas examined in this study. The surface characteristics of the silica particles affected the stabilization ability. The addition of hydrophobic fumed silica can desirably increase MRF magnetic properties.