| 摘要 |
PROBLEM TO BE SOLVED: To obtain an R-T-B anisotropic bond magnet showing an excellent square demagnetization curve by improving the secular change of the magnetic characteristic in a method for manufacturing the magnet by hydrogenation and recrystallization. SOLUTION: When an R-T-B alloy ingot is directly hydrogenated and recrystallized, the shape of the ingot changes before and after the ingot is treated by a hydrogen occluding disintegration method while the temperature of the alloy rises, because the temperature of the ingot is raised in a hydrogen atmosphere. However, when the alloy powder obtained by the disintegration method is molded after the powder is kneaded with an inorganic binder and the molded body is hydrogenated and recrystallized, the secular change of the magnetic characteristic of the molded body is improved as compared with the conventional example and, when alloy powder which is not subjected to the hydrogenation and recrystallization and has an extremely weak coercive force is molded in a magnetic field, the molded body has a high degree of orientation as compared with a molded body obtained by molding powder which is not subjected to the hydrogenation and recrystalliztion and has a high coercive force in a magnetic field. Therefore, when the molded body is hydrogenated and recrystallized, an R-T-B anisotropic bond magnet showing a square demagnetization curve much better than that of the conventional example can be manufactured, because the excellent degree of orientation which is given to the molded body before the treatment does not change. |
