Influence of Perpendicular Magnetic Field on Apparent Density and Microstructure of Magnetic Fluid

Abstract

The formula for a magnetic fluid's apparent density is derived based on Bernoulli's equation of magnetic fluid, and the distribution of the magnetic fluid's apparent density is measured by the intelligent apparatus of measuring a magnetic fluid's apparent density in an applied perpendicular magnetic field. Magnetic particle chain-like alignments are observed by a transmission electron microscope (TEM). Without an applied magnetic field, the magnetic fluid's density is equal everywhere and the distribution of magnetic particles is homogeneous and unordered. When magnetic induction and magnetic induction gradient gather strength in an applied perpendicular magnetic field, the magnetic fluid's apparent density increases gradually, and more chain-like structures are formed and aligned with the direction of the magnetic field. The results of magnetic particle alignments are correspondent with the distribution of the magnetic fluid's apparent density. Both of them result from particle-particle interactions and particle-carrier liquid interactions, which are eventually controlled by the applied magnetic induction and magnetic induction gradient distribution.