Preparation of M-Type Ferrite Fine Particles by Mechanical Compounding Method and Those Characteristic Evaluation

研究了用机械复合法制备的Sr(Ba)-La-Co M型铁氧体微粉制备的块体磁体的磁性能。在块体磁体的制造中，各向异性磁体采用普通烧结工艺，各向同性磁体采用放电等离子烧结和热压工艺。结果表明，在Sr-La-Co M型铁氧体中获得了高性能各向异性磁体{over(BH)max=32kJ/m^3}。在各向同性磁体中，获得了高性能的磁体{over(BH)max=18kJ/m^3}。然而，尽管在制造过程中没有进行各向异性处理，各向异性磁体还是被制造出来了。通过各种方法对这些原因进行分析，发现这些细小的颗粒形状平坦，粒度分布均匀。因此，它似乎将机械取向附加到磁铁上。

This study was carried out to investigate the magnetic properties of the bulk magnets manufactured using Sr(Ba)-La-Co M-type ferrite fine particles prepared by mechanical compounding method. In the manufacture of bulk magnets, anisotropic magnets were made by general sintering process, and isotropic magnets were made by spark plasma sintering and hotpressing process. As the result, it was obtained the high-performance anisotropic magnets {over (BH)max=32 kJ/m^3}with high coercivity in Sr-La-Co M-type ferrite. In the isotropic magnets, the high-performance magnets{over (BH)max=18 kJ/m^3} was obtained. However the anisotropic magnets were made in spite of without anisotropic treatment in the manufacture. As the results of examining these causes by various methods, it was found that the shape of these fine particles was flat, and the particle size distribution was uniform. Therefore, it seem to attach the mechanical orientation to the magnet.