MANUFACTURING METHOD FOR RARE EARTH MAGNET POWDER AND RARE EARTH BOND MAGNET

PROBLEM TO BE SOLVED : To provide a manufacturing method for Sm-Fe-N isotropic magnet powder having excellent magnetic characteristics. SOLUTION : In this method, a raw material containing Sm and Fe is dissolved and the melt is sprayed on a roll to be rapidly cooled to manufacture a ribbon. This ribbon is pulverized to manufacture magnet powder. This magnet powder is heated in nitrogen atmosphere to introduce nitrogen into the crystal lattice of the magnet powder to manufacture the Sm-Fe-N isotropic magnet powder. The surface layer of this magnet powder is removed by a dilute nitric acid solution. Thus, manufactured ribbon by spraying the melt on the roll to rapidly cool it, has magnetic characteristics at the roll surface and the free surface thereof inferior than those at the interior of the ribbon. However, because the surface layer of the magnet powder is removed by the dilute nitric acid aqueous solution, the surface layers at the roll surface and the free surface of the ribbon are removed, so that the Sm-Fe-N isotropic magnet powder having excellent magnetic characteristics can be manufactured.