Behaviour of magnetic particles in compaction

A purpose of this study is to perform a compaction process of ferromagnetic powder for optimizing magnetic characteristics in producing a magnetic recording medium or a permanent magnet. The magnetic powder is treated as an assembly of particles. A circular disk and an elliptical disk are employed as particle models. To simulate the behavior of the particles, a particle dynamics simulation is proposed, where Coulomb's law for magnetized particles, torque by an applied magnetic field, elastic repulsive force due to Hertzian contact and friction force are considered. A relationship between the direction of the applied magnetic field and motion of the punch is examined. It is commonly considered that easy directions of magnetization are oriented constantly in the direction of an applied magnetic field. However, the simulated results show that the particles are not aligned so because of the interaction forces between the magnetized particles.