Characterization of Magnetorheological Fluidsproduced Using Selected Carbonyl Iron Powders

Carbonyl iron powders (CIP) are characterized by high purity, uniformity of particle shape and size,high saturation magnetization, and resistance to oxidation. These properties, as well as good stability andavailability, make them particularly useful for producing fluids with controllable rheological properties.Among such substances are magnetorheological (MR) fluids, which are heterogeneous mixtures of particlesof material with ferromagnetic properties in a non-magnetic carrier fluid. Interaction of MR fluids with amagnetic field enables an almost instantaneous and fully reversible change in the consistency of this type offluid, ranging from a thin fluid state to complete solidification into a structure with a shear strength of severalhundred kPa. The paper presents the results of studies of MR fluids produced on the basis of carbonyl ironpowders offered by BASF. The authors determine the influence of the physical properties of selected types ofCIP powders, i.e. particle size and their magnetic properties, on the magnetorheological effect and conducta comparative analysis of the characteristics of the developed MR fluids and to evaluate their suitability fortechnical applications.