MAGNETORHEOLOGICAL CHARACTERIZATION OF CARBONYL IRON BASED SUSPENSION STABILIZED BY FUMED SILICA

초록

Magnetorheological (MR) fluids are suspensions consisting of magnetic particles and non-magnetic liquid medium, and soft ferromagnetic materials such as magnetite and iron are generally used to MR materials. Using carbonyl iron (CI) suspended MR fluid, the flow behaviors were investigated in both steady and oscillatory shear modes and analyzed in terms of the internal structure formation by a precise control of the external magnetic fields, in which 30.8 vol % of CI was dispersed in mineral oil similar as electrorheological fluid.1 At the same time, we also prepared the CI-MR fluid with the addition of fumed silica to enhance the stabilization of MR fluid, and compared the overall rheological properties and sedimentation characteristics with those of CI-MR fluid without an additive using a rotational rheometer (MCR-300, Physica, Germany) equipped with a magnetic field generator.