Study of Magnetorheological Grease’s Thermomagnetic Coupling Rheology

Abstract

The controllable rheological properties of magnetorheological grease offer significant application prospects in regulating the lubrication behavior of frictional substrates. A novel nano-magnetorheological grease was prepared using nanoscale manganese ferrite as magnetic particles. The prepared magnetorheological grease underwent magnetic field scanning and rate scanning studies under thermomagnetic coupling, and we investigated the variation patterns of rheological parameters under different temperatures and magnetic field intensities. The Herschel–Bulkley rheological model was utilized for data fitting to determine the shear yield stress of the magnetorheological grease. Furthermore, the variation patterns of shear yield stress with increasing magnetic field intensity were explored. The results demonstrated that the apparent viscosity and shear stress of the magnetorheological grease decreased with increasing temperature, while they increased with enhanced magnetic field intensity. The apparent viscosity of the magnetorheological grease decreased with increasing shear rate. Additionally, the shear yield stress of the magnetorheological grease decreased with a temperature rise, but increased when an external magnetic field was applied. The adverse effects of high temperature on the magnetorheological grease could be mitigated by the application of an external magnetic field.