Microstructure and magnetic properties of anisotropic NdFeB powders from hot rolled ingots by HD process

Hot rolling of cast Nd/sub 16.5/Fe/sub 77.5/B/sub 6/ ingots wrapped in iron was used to produce anisotropic magnets as starting material for anisotropic powder. After application of the HD process the NdFeB powder could be easily removed from the sheath. Metallographic and SEM investigations showed a great variety of particle shapes and sizes. Predominantly needle- and shell-shaped particles with medium particle sizes of about 160 /spl mu/m were formed with their magnetically easy axis perpendicular to the great half axis. To produce anisotropic bonded magnets the aligning magnetic field has to be applied parallel to the pressure direction.<
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