Carbonyl iron based magnetorheological effects with silver nanoparticles via green-assisted coating

Abstract

Carbonyl iron (CI) particles are widely used in magnetorheological (MR) fluids due to their excellent magnetic properties, i.e., high saturation magnetization and low coercivity. However, pristine CI-based MR fluids have major shortcomings, which restrict their applications: abrasion of device surfaces during operation, redispersion difficulties after caking, iron oxidation, and severe sedimentation of CI particles due to higher density compared to the carrier liquid. As a remedy, the CI particles were coated with Ag shell by green-assisted method and stabilized with honey. The CI and CI-Ag particles were separately dispersed in Polyalphaolefin (PAO) oil, and the subsequent rheological effects were evaluated. Although the MR effects, e.g., yield stress and shear viscosity of CI-Ag-based MR fluids, varied slightly compared to the original one, the dispersion qualities, e.g., sedimentation stability, were remarkably improved.