Enhanced magnetorheology of soft magnetic carbonyl iron suspension with binary mixture of Ni-Zn ferrite and Fe3O4 nanoparticle additive

Fe3O4 and Ni0.5Zn0.5Fe2O4 nanoparticles were synthesized via precipitation and mechanical alloying, respectively, and assessed as a potential magnetorheogical (MR) additive. X-ray diffraction and transmission electron microscopy were employed to evaluate the phase formation and structural and morphological changes. Vibrating sample magnetometer (VSM) was used to measure magnetic characteristics of the samples. The MR characteristics of carbonyl iron (CI)-based and 1 wt.% (Ni0.5Zn0.5Fe2O4 + Fe3O4) CI-based suspensions were measured from a steady and rotational rheometry by applying magnetic field strengths ranging from 0 to 558.39 kA/m with 79.77-kA/m increments. The results indicated that the MR effect of the micron-sized, CI-based MR fluid significantly improved in the presence of nanoparticle additives, e.g., having higher-yield characteristics. Chain-like structure formed in the presence of nanoscale additives improved the MR performance and sedimentation stability of the CI particles

Properties of plate-like carbonyl iron particle for magnetorheological fluid

This work experimentally discussed the characterization, magnetic, and rheological properties of plate-like carbonyl iron particle (CIP) in comparison with conventional spherical CIP. Plate-like CIP was produced by using ball milling method. The effect of plate-like shape on the magnetic behavior of CIP was firstly investigated by vibrating sample magnetometer (VSM). The results indicated that the plate-like CIP obtained higher saturation magnetization (about 8%) than that of the spherical particles. In addition, the field-dependent rheological properties such as yield stress were investigated and the results are compared between two particles as a function of the magnetic field intensity

A comparison of field-dependent rheological properties between spherical and plate-like carbonyl iron particles-based magneto-rheological fluids

This work proposes different sizes of the plate-like particles from conventional spherical carbonyl iron (CI) particles by adjusting milling time in the ball mill process. The ball mill process to make the plate-like particles is called a solid-state powder processing technique which involves repeated welding, fracturing and re-welding of powder particles in a high-energy ball mill. The effect of ball milling process on the magnetic behavior of CI particles is firstly investigated by vibrating sample magnetometer. It is found form this investigation that the plate-like particles have higher saturation magnetization (about 8%) than that of the spherical particles. Subsequently, for the investigation on the sedimentation behavior the cylindrical measurement technique is used. It is observed from this measurement that the plate-like particles show slower sedimentation rate compared to the spherical particles indicating higher stability of the MR fluid. The field-dependent rheological properties of MR fluids based on the plate-like particles are then investigated with respect to the milling time which is directly connected to the size of the plate-like particles. In addition, the field-dependent rheological properties such as the yield stress are evaluated and compared between the plate-like particles based MR fluids and the spherical particles based MR fluid. It is found that the yield shear stress of the plate-like particles based MR fluid is increased up to 270% compared to the spherical particles based MR fluid

Investigation on magnetic field dependent modulus of epoxidized natural rubber based magnetorheological elastomer

This paper presents an investigation on the use of epoxidized natural rubber (ENR) as a matrix of magnetorheological elastomers (MREs). Isotropic ENR-based MRE samples were synthesized by homogeneously mixed the ENR compound with carbonyl iron particles (CIPs). The microstructure of the sample was observed, and the magnetic field-dependent moduli were analyzed using rheometer. The influences of excitation frequency, CIPs content and magnetic field on the field-dependent moduli of ENR-based MREs were evaluated through dynamic shear test. The microstructure of MRE samples demonstrated the dispersed CIPs in the ENR matrix. The remarkable increment of storage and loss moduli of the ENR-based MREs has exhibited the magnetically controllable storage and loss moduli of the samples when exposed to the magnetic field. Consequently, the CIPs content, frequency and magnetic field were significantly influenced the dynamic moduli of the ENR-based MREs