Magnetic liquids are a kind of nano-scale functional material with fluidity and superparamagneticity, which is mainly composed of nano-magnetic particles, base liquids and surfactants. Its characteristics mainly include magnetization, levitation, magnetoviscous effect. Compared with the traditional vibration damper, the vibration damper used in spacecraft based on these features has the peculiarity of small volume, low quality, sensitive to inertial force, and does not rely on spacecraft to provide additional energy. There are successful application cases in foreign aerospace and other fields, while the domestic is limited to some theory and experiment, the practical application is less, the lack of in-depth study. More than half of spacecraft failures are caused by vibration, so it is necessary to reduce the vibration of spacecraft. This paper briefly introduces the composition, preparation and characteristics of magnetic liquids, and reviews the typical applications of magnetic liquids in vibration reduction from the 20th century to the present, including the research on vibration reduction of spacecraft, loudspeakers and workbenches.

A mathematical model of a mutual inductance magnetic fluid inclination sensor is established. The sensing element of the sensor is magnetic fluid. The composite magnetic core suspended in the magnetic fluid increases the permeability of the medium in the winding. The total magnetic induction intensity B in the winding is composed of two parts: the excitation magnetic induction intensity Bl and the additional magnetic induction intensity Ba generated by the magnetization of pure iron. The sensitivity S of the sensor and its influencing factors are derived. The output characteristics of the sensor are analyzed using ANSYS Maxwell simulation software. The results show that the variable resistance of the measuring circuit can eliminate the residual voltage at zero point, and the output voltage carrier after filtering and rectification is positive half cycle; The addition of pure iron to the magnetic core greatly increases the mutual inductance variation between the primary and secondary windings, and the inclination angle in a small range is linear with the mutual inductance variation; The recovery force of the composite core is proportional to the displacement.