| 摘要 |
<p>Provided is a permanent magnet producing method whereby a high ratio of utilization of an evaporation material can be achieved. In the present invention, at least two evaporation material (RM) plates containing at least one selected from Dy, Tb, and Ho are placed in a treatment chamber (3) so as to face each other with a distance therebetween, and a plurality of iron-boron-rare earth-based sintered magnets (S) are arranged between the evaporation material plates. The inside of the treatment chamber is heated under a reduced pressure so that the sintered magnets are heated to a predetermined temperature and the evaporation material is evaporated. The at least one selected from Dy, Tb and Ho, which is thus evaporated, is caused to adhere to surfaces of the sintered magnets in such a manner that the amount of supply of the same is adjusted. The at least one selected from Dy, Tb and Ho, which thus adheres to the surfaces, is diffused over grain boundaries and/or grain boundary phases of the sintered magnets. The ratio of a sum of areas of surfaces of the sintered magnets facing the evaporation material plates to a sum of areas of surfaces of the evaporation material plates facing the sintered magnets is set in a range of 20% to 120%.</p> |
