MANUFACTURING OF ND-Fe-B MAGNET USING HOT PRESSING WITH REDUCED DYSPROSIUM OR TERBIUM

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PROBLEM TO BE SOLVED : To provide a method for increasing the uniformity of Dy distribution by not adding a heavy rare earth metal such as Dy or Tb which is a rare and expensive material, but increasing Dy distributed along a grain boundary in order to reduce an amount of Dy used for the purpose of improving a permanent magnet in thermal stability and high-temperature magnetic property. SOLUTION : A method for manufacturing a magnetic material for a permanent magnet using one of hot-pressing and die-upset methods, or both, by combining two kinds of powder and optimizing grain boundary diffusion of Dy or Tb comprises : using hot pressing using core powder containing Nd, Fe and B and surface powder containing Dy or Tb in metallic alloy form; combining the materials; forming a solid material in a shaping die under a magnetic field in vacuum; heating the solid material; hot pressing the solid material to form a magnetic material in the die; performing a heat-treatment on the magnetic material if necessary; and then cooling it. COPYRIGHT : (C)2015, JPO&INPIT