| 摘要 |
There is a two-alloy method in the production methods of sintered alloy, in which the R2Fe14B phase is the main magnetic phase. In this method, the main phase alloy having lower R content than R2Fe14B phase and the boundary phase having rich R content for feeding the liquid phase in the sintering are mixed and used as the raw material. The conventional main-phase alloy has a structure which contains, in addition to the R2Fe14B phase, a large amount of lamellar R-rich phase which is easily oxidizable, and also a detrimental alpha phase. The main-phase alloy provided by the present invention contains a lamellar alpha phase, while the dendritic alpha phase and lamellar R-rich phase are decreased. The oxidation resistance is therefore improved, and hence the properties of a magnet are enhanced. In addition, when the sintered magnet is produced by the two-alloy method by means of mixing the main-phase alloy and the boundary phase alloy according to the present invention, the abnormal growth of crystal grains can be suppressed. <IMAGE> |
