Influence of Graphite Flakes on the Strength of Magnetorheological Fluids at High Temperature and its Rheology

Magnetorheological fluid (MRF)-based rotating torque transmission devices are gaining popularity such as MR brake and MR clutch. The effectiveness of the developed devices reduces due to thermal thinning behavior such as a decrease in strength at high temperature of MRF. To design MR devices such as MR clutch and MR brakes, it is necessary to maintain the strength of MRF at the higher temperature. Since MRF is the main component of MR devices, the synthesis of good quality MRF is a prime concern. In this research article, the role of graphite flakes on the strength of MRF at high temperature and its rheology is investigated. In this article, the effectiveness of graphite flakes is tested on MRF by selecting different weight fractions. MRF and MRF with graphite flakes (MRFG) have been synthesized with carbonyl iron particles (80 wt%) and graphite flakes (0.5, 1, 2, 3, 4, and 5 wt%). MRF and MRFG are characterized or evaluated by the rheometer. The rheological properties of MRF and MRFG have been examined using rotational tests. Results show the effective use of graphite flakes in MRF. MRFG has a higher value of shear stress than the MRF at high temperature and shear rate.