Preparation And Characterization Of SED3A/CI Composite Magnetic Particles And Oil Based Magentorheological Fluids

Magnetorheological (MR) fluids are substances that exhibit rather unique properties of being able to reversibly change their apparent viscosity through the application magnetic field. MR fluids have wide application in vibration damper devices such as, shock absorbers, vibration dampers, force/torque transfer (clutch) devices ect, However, since most of the magnetic particles used for the MR fluids have sizably high densities compared to the suspending medium, the sedimentation stability of MR fluids needs to be improved in order for the application of MR fluid devices to be practicable. In this study, a new method was designed for preparing novel MR fluids with better dispersion stability, magnetorheological effect. First , SED3A, which has pro-oil groups and chelating groups, was synthesized, and used to modify the surface characteristics of carbonyl iron (CI) particles and prepare composite magnetic particles CMPs. Then oil-based MR fluids based on the composite magnetic particles were prepared.The structure and properties of SED3A and CMPs were characterized by FT-IR, the contact angle test, SEM, XRD, VSM ; The anti-oxidization and anti-acidification experiments were designed to investigate the anti-oxidization and anti-acidification properties of CMPs. The results show that SED3A had been successfully synthesized; CMPs which possessing excellent soft magnetic proerties, better anti-oxidization and dispersion stability in oil were successfully prepared,The Magnetization of MR fluids were synthesized, the result show that the Magnetization of MR fluids have a relationship with the Magnetization of CMPs and the volume of MR fluids; The disperison stability, zero field viscosity, field-induced shear stress and dynamic modulus of oil based MR fluids had been investigated by sedimentation experiment, magnetorheological effect analysis. The results show that oil MR fluids have better dispersion stability, lower zero field viscosity, higher switch factor and larger dynamic modulus.The resluts in this study showed that the CMPs, made by chelating surfactant modifying the surface of CI particles, have better dispersion stability in oil. Using these CMPs preparation oil-based MR fluids can improve dispersion stability and magnetorheological effect. This method designed for preparing oil MR Fluids is an easy way to put it into practical.