Magnetorheological (MR) materials are smart composite materials that are typically made of highly magnetizable micron-sized particles (up to 50% by volume) dispersed in a non-magnetizable fluid medium. This arrangement causes the fluid to exhibit a reversible and virtually instantaneous transition from a low-viscosity liquid to a virtually solid state with exact controllability when placed under an external magnetic field. In general, MR fluid particulates must have a high saturation magnetization and small remanent magnetization, as well as be active over a wide temperature range and be stable against sedimentation, irreversible flocculation, and chemical degradation. Based on these criteria for the magnetic constituents of an MR fluid, carbonyl iron particles are commonly used for MR fluids due to their high saturation magnetization (M = 2.216[4]) (cobalt and nickel are also commonly used ). Along with magnetizable particulates, the other 3 main constituents of MR fluids are: the carrier fluid (mineral or silicone oil), dispersants (to minimize particle coagulation), and gelling additives. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an original essay Due to the nature of the magnetorheological effect, an incredible level of precision in the controllability of their viscosity as the magnetic field strength can be manipulated down to the most minute level. This controllability, along with the low energy demand and wide temperature range, makes them incredibly desirable for numerous engineering applications, particularly those requiring active vibration control and torque transfer, typical examples include: shock absorbers, brakes, clutches and control valves; Despite their attractiveness in many applications, a challenge remains for their commercialization, namely achieving the highest possible performance stress with the lowest input energy. Due to the inherent nature of current MR fluids, the suboptimal yield stress, and the value of the strongest MR fluids, any improvements are highly sought after. A well-documented feature of MR fluids is that as the spherical particles become larger, the yield stress of the MR fluid also increases; However, the huge disadvantage of increasing the size of the dispersant is the increased instability of the fluid since the difference in density between the dispersant and its suspension causes exponentially increasing sedimentation rates, thus making the use of larger particles impractical. . A potential solution to this problem is the use of microwire structures. Typically around 200 to 300 nm in diameter and 3 to 13 micrometers long, they show the same increase in yield stress but markedly reduced sedimentation rates compared to their spherical analogue or potentially using a mixture of sizes in a bidisperse MR or poly dispersing fluid.Microwire StructureBell et al 2008 conducted research on this topic. Their method consisted of using two distinct length distributions of pure iron microwires of 5.4 ± 5.2 μm and 7.6 ± 5.1 μm each with a diameter of 260 ± 30 nm. Using spherical iron particles with diameters of 1–3 μm in a silicone oil suspension were used to replicate conventional MR fluids as a control. Their experiment method was to use an Anton-Paar Physica MCR300 parallel plate rheometer equipped with an MRD180 for rheological measurements with a gap of 1 mm 4.