| 摘要 |
This invention, using finely ground powders obtained by either a ingot grinding method, a Ca reduction diffusion method or a strip casting method, proposes a fabrication method for high-performance R-Fe-B permanent magnets with excellent press packing characteristics, a high degree of orientation of the magnetization direction of each crystallite and a total sum of A, (BH)max (MGOe) and B, iHc (kOe), A+B greater than 59.5. Here, cast alloys or ground alloys are coarse ground by mechanical grinding or by a H2 absorption and decomposition method, and then fine ground by either mechanical grinding or by a jet mill grinding process to yield R-Fe-B fine powders with an average particle size of 1.0 mu m DIFFERENCE 10 mu m. These powders are then packed into a mold at a packing density of 1.4 DIFFERENCE 3.5 g/cm3, a pulsed magnetic field with a field intensity greater than 10 kOe is applied so as to repeatedly invert the magnetization direction, and finally cold isostatic pressing is performed in a static magnetic field.
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