Effect of MXene nanosheets attached to carbonyl iron microspheres on the performance and stability of magnetorheological fluid

To improve the sedimentation stability of carbonyl iron (CI)-based magnetorheological fluid (MRF), a novel MRF with CI/MXene particles as dispersed phase was prepared. CI/MXene particles were prepared by attaching the lightweight MXene nanosheets onto the surface of CI particles (CIPs) as an additive. The micro-morphology, crystal structure and element composition of CI/MXene particles were analyzed by SEM, XRD and XPS characterization respectively, which confirmed the successful synthesis of CI/MXene particles. CI/MXene-based MRF possessed considerable high magnetorheological (MR) effect, and the magneto-induced shear stress was up to 49 kPa. More importantly, the sedimentation ratio of CI/MXene-based MRF was further characterized to evaluate its stability. Experimental results showed that the sedimentation ratio of MRF increased from 75.7% to 98.0% after mixing CIPs with 3 wt% MXene nanosheets. The sedimentation ratio of CI/MXene-based MRF increased by 29.5% compared to CI-based MRF. As a result, the addition of MXene nanosheets significantly improved the sedimentation stability of MRF while maintained high MR effect.