Tribological Performance of Magnetorheological Fluid in Compliant Contact

Abstract The current challenge with magnetorheological (MR) damper technology lies in its limited durability, primarily due to the abrasive nature of ferromagnetic particles. The critical component appears to be the seal, representing a soft contact. This comparative study focuses on testing the friction coefficient (COF) and wear loss of compliant contacts immersed in magnetorheological fluid. This article presents wear loss and the coefficient of friction for six selected sealing materials flooded by MR fluid. Furthermore, the effect of particle concentration on wear loss is also tested. Finally, the effect of long-term loading of MR fluid on tribological properties is presented. The results show that the polyurethane-based sealing material exhibited the lowest wear, while polytetrafluoroethylene (PTFE) exhibited the lowest COF. Polyurethane materials were found to be approximately 3.5 times more resistant to abrasion than nitrile butadiene rubber seals and 2.5 times more resistant than PTFE. The concentration of particles in MR fluids within the tested range (22–40 vol%) did not significantly affect abrasiveness. It was found that MR fluid subjected to long-term mechanical loading exhibited nearly a threefold increase in abrasiveness compared to new MR fluid. Consequently, it can be concluded that long-term mechanical loading of MR fluid has a substantial impact on its tribological properties. However, a more detailed study of tribological properties changes with long-term loading is the subject of further research.