Abstract
MR (Magnetorheological) fluids are the suspensions composed of micron-sized ferromagnetic particles dispersed into carrier oil, and are one of smart fluids which can be changed their rheological properties in reversible manner by applying magnetic field. From the viewpoint of the applications, the no-field initial viscosity of the MR fluids should be regulated as low as possible to minimize the energy loss, and the operating temperature should be higher. However, since the carrier medium is a liquid, the limits of the viscosity minimization and the operating temperature exist. In this research, in order to develop of the MR fluid of extremely low no-field viscosity and higher operating temperature, novel "dry MR fluids" have been fabricated, and the fluidity and MR properties have been measured and evaluated. The dry MR fluid is a novel MR fluidic powder, which is mainly composed of micron-sized carbonyl iron particles coated with nano-sized particles without liquid medium.
