Procédé de fabrication d'aimants Nd-Fe-B totalement denses à microstructure à gradient et coercivité améliorée

摘要

The present invention relates to a method of manufacturing fully dense Nd-Fe-B magnets by mixing Nd-Fe-B ribbons with a powder containing a heavy rare earth metal. The mixture comprises 1-4 wt% of the heavy rare earth metal and is in the first step spark plasma sintered to a fully dense nanocrystalline Nd-Fe-B magnet and subsequently in a second step annealed to allow the diffusion of the heavy rare earth metal. With this method an enhancement of coercivity of approximately 30 % can be achieved.