Agglomeration of magnetic fine particles in fluid dispersion

Publisher Website
Google Scholar
Abstract
Agglomeration of γ‐Fe2O3 acicular magnetic particles in concentrations of approximately 0.005% by weight in water was studied by measuring light transmission through the dispersions while they were subjected to a stepwise rotating magnetic field of 15‐Oe magnitude. Transmitted light intensity varies synchronously with rotation, having its minimum when particles are aligned with their long axes parallel to the light and its maximum when particles are perpendicular to the beam. With time, the minimum light level diminishes, whereas the maximum light condition remains constant. This behavior is attributed to the formation and growth of particle chains. The chaining idea is supported by the observation that the response time of particles to the changing field increases with time and by other optical effects which are observed in high‐speed rotation of the field. The effect of milling time on particle mobility is also observed. The observations are discussed in terms of a model of the attraction and attachment behavior of dilutely dispersed magnetic particles in a fluid.

This publication has 8 references indexed in Scilit: