Synthesis of calcium ferrite nanocrystal clusters for magnetorheological fluid with enhanced sedimentation stability

In this study, we prepared calcium ferrite (CaFe2O4) nanocrystal clusters by a solvothermal method and evaluated their application potential in magnetorheological (MR) fluid. The morphology, composition, microstructure and magnetic properties of the CaFe2O4 nanocrystal clusters were investigated in detail. The as-prepared CaFe2O4-based MR fluid showed typical Bingham fluid behavior, changing from a liquid-like to a solid-like structure under an external magnetic field. Compared with carbonyl iron (CI) particles, the MR fluid based on CaFe2O4 nanocrystal clusters showed enhanced sedimentation stability, which can be mainly due to the reduced density mismatch between dispersed phase and carrier fluid. In conclusion, the as-prepared CaFe2O4 nanocrystal clusters are considered as a promising candidate for high-performance MR fluid.