MANUFACTURE OF COMPOSITE MAGNET

摘要

PURPOSE:To enhance anti-stress-cracking qualities of a mold by adding a non- magnetic inorganic compound having its enhanced degree of sphere to a kneaded material composed of ferromagnetic powder and a polymeric compound to decrease change in dimension, warpage and the like of the mold. CONSTITUTION:Kneaded material composed of 80-96wt% of ferromagnetic powder and 3.90-19.98wt% of a polymeric compound is filled with 0.02-5wt% of non-magnetic inorganic filling material of which degree of sphere is enhanced. The kneaded material is injection-molded in a magnetic field. Such addition of the filling material lightens shrinkable anisotropy of the mold caused by making the magnetic field anisotropic and orientation of resin components caused by injection molding in the magnetic field. Enhancement of the degree of sphere of the filling material allows the filling material to be uniformly spreaded and filled without lowering filling density of ferromagnetic powder.