Dependency of the Magnetic Particles' Alignment on Relative Density in Applied Magnetic Field
Hidetoshi KOTERA, Susumu SHIMA and Harunori KITAHARA
Abstract:The effect of the relative density of magnetic powder on particles' rotation in an applied magnetic field during compaction is studied. For producing permanent magnets, magnetic powder is compressed in a magnetic field to impart a high residual strength for@magnetization. The magnetic particles are aligned in the magnetic field, and the magnetic powder is subjected to plastic deformation during compression. The magnetic particles are forced to rotate and transform both by the mechanical force and magnetic force. Although it is commonly known that the relative density of the powder affects the rotation and deformation of the constituent particles, a quantitative study of the effect of powder density on the particles' alignment has not been undertaken with a view to application for designing the compaction process in magnetic field. In this study, we carry out magnetic powder compaction in magnetic field after pre-compression without a magnetic field. We also calculate the particles' alignment by the magnetic Cosserat continuum theory. Both the calculated and experimental results show the dependency of the particles' alignment on the relative density at which the magnetic field is applied. Key Words:Magnetic particle, Magnetic powder, Compaction, Particles' alignment, Cosserat continuum theory