| 摘要 |
PURPOSE:To contrive improvement in magnetic characteristics using compositionally deviated alloy powder by a method wherein the time, at which inert gas will be introduced for the purpose of converting a vacuum atmosphere into an inert atmosphere, is judged from the linear relation between the composition after performance of an aging treatment and the time when inert gas is introduced. CONSTITUTION:The molded product obtained by molding the compositionally deviated alloy powder of the light rare-earth elements such as Nd, Pr and the like in a magnetic field is sintered in a vacuum atmosphere. Subsequently, said sintered product is cooled down slowly, and an aging treatment is conducted in the inert atmosphere such as Ar gas and the like. The time at which the inert gas will be introduced is arbitrarily set at least at twice between the period when the sintering operation is finished and the starting of the aging treatment. Other condition required when the title permanent magnet is fixed is that a decision is given so as to obtain the desirable composition from the linear relation between the composition obtained after the aging treatment has been finished and the time when the inert gas is introduced. The linear relation can be obtained if there are at least two sets of data on composition and gas introducing time. The heat-treated material is quenched from the aging temperature, and after a sintered body is obtained, it is magnetized and a permanent magnet is formed. |
