Performance Tests and Microchain Model Validation of a Novel Kind of MR Fluid with GO-Coated Iron Particles

Abstract

Magnetorheological (MR) fluids are suspensions of microparticles or nanoparticles dispersed in carrier fluids, which contain iron particles, carrier fluids and additives. In this study, a novel kind of composite iron particle—graphene oxide (GO)-coated magnetic particles was adopted to prepare MR fluids together with surfactants-modified iron particles. The influence of dosage proportions of the two composite iron particles, volume fraction of iron particles, and the dosage of liquid paraffin on the performances of MR fluids was investigated through sedimentation stability, viscosity, and shear yield stress tests. The test results presented that GO-coated iron particles with low density and high-saturation magnetization were beneficial to the improvement of stability and adjustability. Additionally, dosage proportions of the two composite iron particles, volume fraction of iron particles, and the dosage of liquid paraffin all had significant influence on the performances of MR fluids. Finally, the mathematical model of shear yield stress of the MR fluid was deduced, and the calculated results were compared with the tested data, which had verified the correctness of the mathematical model.