Effect of reduced graphene oxide and MnFe2O4 nanoparticles on carbonyl iron for magnetorheological fluids

This study introduces magnetic MnFe2O4 nanoparticles and graphene oxide (GO) nanosheets to enhance magnetorheological (MR) properties and dispersion stability of the carbonyl iron (CI)-based MR fluid. The prepared CI/MnFe2O4/GO was transformed into CI/MnFe2O4/rGO through an annealing process and was used as an additive of the MR fluid. The shape, crystallinity, and magnetic properties of the composite were analyzed via SEM, TEM, EDS, XRD, and vibrating sample magnetometer. In addition, rotational rheometer and Turbiscan were used to examine the MR properties and dispersion stability of the MR fluid, respectively. The CI/MnFe2O4/rGO-based MR fluid exhibited higher shear stress, shear viscosity, and storage modulus than the CI-based MR fluid. The dispersion stability was enhanced due to GO with its low density and a large specific surface area, and the sedimentation ratio was improved approximately by 17% after 24 h owing to the reduced difference in the density between the magnetic particles and oil medium. (C) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.

Automated summary

This study introduced magnetic MnFe2O4 nanoparticles and graphene oxide to enhance the magnetorheological properties and dispersion stability of carbonyl iron-based MR fluid. The prepared CI/MnFe2O4/GO was transformed into CI/MnFe2O4/rGO through an annealing process and used as an additive for the MR fluid. The CI/MnFe2O4/rGO-based MR fluid exhibited improved shear stress, shear viscosity, and storage modulus compared to the CI-based MR fluid, with enhanced dispersion stability attributed to the properties of GO.