Preparation of Magnetic Compound Fluids Containing Needle-like Magnetic Particles and Its Damping Property

Abstract

　Needle-like magnetic particles were added to magnetic compound fluids containing both 10 nm-size magnetic particles and several micrometer-size magnetic particles, and damping properties of these fluids were investigated experimentally by using a simple prototype damper. Damping force depends on the mixing ratio of three kinds of magnetic particles: 100 nm-size needle-like magnetic particles, 10 nm-size spherical magnetic particles and 1 micrometer-size spherical magnetic particles. Magnetic compound fluid containing needle-like magnetic particles behaves like a dilatant fluid basically even in the presence of magnetic field, while the fluid can be treated as a Bingham fluid or a pseudoplastic fluid in the presence of strong magnetic field.