Abstract
High-energy-compaction-molded bonded magnets, composed of anisotropic Nd-Fe-B powder and epoxy resin, were developed. The influence of the binder on the magnetic properties and the degree of magnetic orientation was investigated. The results show that the frictional force between powders is decreased by warm-compaction molding and by using a binder with low melt viscosity. Magnets made by this method have a powder volume fraction and degree of magnetic orientation of 78.1% and 97.6%, respectively; these values are significantly higher than those for a cold-compaction-molded magnet. In order to suppress thermal degradation of the magnetic powder in the curing process, an epoxy resin that can be cured at 120°C was used for bonding. The (BH)max of a typical bonded magnet is 20.3 MGOe, which is 58.5% of the value for the powder.
