METHOD FOR MANUFACTURING RARE-EARTH PERMANENT MAGNETIC MATERIAL

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A method for manufacturing a rare-earth permanent magnetic material comprises manufacturing a NdFeB magnetic from NdFeB alloy powder by two consecutive compression molding processes. An oriented magnetic field is applied in the first molding process to obtain an anisotropic NdFeB green body, and heating and pressing are applied in the second molding process to obtain a dense NdFeB magnetic having a size close to that of a final product. The performance of the magnetic is enhanced through a special thermal treatment process, which involves a low densification temperature that suppresses the enlargement of crystals, and thus provides crystals that are smaller compared to those of a sintered magnet and that have high magnetic performance. By adopting the molding processes, the size of a magnet is close to that of a final product, and the material utilization rate is much greater than that of a conventional sintered NdFeB magnet. Further, the method does not require a dedicated fast-quench magnetic powder or thermal deformation, providing a simple process, high production efficiency, production costs far lower than those of a thermal pressed/thermal deformed magnetic, and high magnetic performance achieving a maximum magnetic energy product above 200 kJm-3, much higher than that of a bonded NdFeB magnet.