Enhanced magnetorheological response of magnetic chromium dioxide nanoparticle added carbonyl iron suspension

Hard-magnetic chromium dioxide nanoparticles with a rod-like shape were introduced as an additive to a soft-magnetic carbonyl iron (CI)-based magnetorheological (MR) fluid. The magnetic stimuli-response of the MR fluid in terms of the steady shear and dynamic oscillation tests was examined using a rotational rheometer. While the Bingham fluid model fitted the flow curves, the dynamic yield stress followed the universal yield stress scale function quite well. Compared to the CI-based MR fluid without chromium dioxide nanoparticles, the MR fluid with the chromium dioxide additive exhibited remarkably higher yield behavior with increasing magnetic field strength, enhancing its MR performance and dispersion stability.