ABSTRACT: It is a great challenge to make a balance between magnetorheological (MR) effect and sedimentation stability for magnetorheological (MR) fluids. Iron nanoparticle would be a good candidate to achieve this balance, but it lacks efficient preparation method. In this study, a DC arc discharge method was used to prepare iron nanoparticles. Their morphology, magnetic properties, crystal structures and surfaces chemical composition were examined, which confirmed their nano size (~40 nm), high saturation magnetization (~146 emu/g), and high purity. The iron nanoparticles and commercial carbonyl iron micro-sized particles were used as the dispersing phase to prepare MR fluids, respectively. Their magnetorheological effect and sedimentation stability were measured for comparison. The results indicate that the iron nanoparticles-based MR fluids present a slight lower MR effect, but much better sedimentation stability with respect to the MR fluids with carbonyl iron micro-sized particles

DOI: 10.1016/j.jmmm.2019.165556