10: Review of Magnetorheological Fluids as Smart Materials

Chapter 10 reviews magnetorheological fluids (MRFs), which are suspensions of micron-sized magnetic particles such as iron carbonyl powder in a host liquid which is usually a type of oil with some additives to minimize particle sedimentation and particle wear and tear. When the MRF suspension is placed in a magnetic field, the suspended colloidal particles reconfigure to form chains in the direction of the magnetic flux and make the solution more solid-like than liquid. This new particle configuration, which shows some microstructure within the suspension sharply increases the apparent viscosity and the yield stress of the MRFs within milliseconds.