MnFe2O4 Nanoparticles Anchored on the Surface of MgAl-layered Double Hydroxide Nanoplates for Stable Magnetorheological Fluids

In the present study, the manganese ferrite (MnFe2O4) nanoparticles were controllably anchored on the surface of MgAl-layered double hydroxide (MgAl-LDH) using a facile two-step hydrothermal method, and the as-prepared MnFe2O4/MgAl-LDH nanocomposites were adopted as the magnetic dispersed phase to prepare a stable and uniform magnetorheological (MR) suspension. The obtained MnFe2O4/MgAl-LDH nanocomposites were deeply characterized by XRD, TEM, XPS, BET and SQUID, and the viscoelastic properties of MnFe2O4/MgAl-LDH based MR fluid were investigated in detail under the action of different magnetic fields. More importantly, the results of sedimentation tests showed that the sedimentation stability of MnFe2O4/MgAl-LDH based MR fluid was much higher than that of carbonyl iron (CI) particles based MR fluid. The improved sedimentation stability can be attributed to the special plate-like structure, high specific surface area and reduced density difference.