PROCESS FOR PRODUCING NDFEB-BASED SINTERED MAGNET

• Main Authors: UNE YASUHIRO, MIZOGUCHI TETSUHIKO, SAGAWA MASATO
• Format: Patent
• Language: English; Korean
• Published: 23.12.2014
• Subjects: ALLOYS; BASIC ELECTRIC ELEMENTS; CASTING; CHEMISTRY; ELECTRICITY; FERROUS OR NON-FERROUS ALLOYS; INDUCTANCES; MAGNETS; MAKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; METALLURGY; PERFORMING OPERATIONS; POWDER METALLURGY; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES; TRANSFORMERS; TRANSPORTING; TREATMENT OF ALLOYS OR NON-FERROUS METALS; WORKING METALLIC POWDER

An objective of the present invention is to provide a method for producing a NdFeB system sintered magnet which, when used as a base material in a grain boundary diffusion method, allows R H to easily diffuse through a rare-earth rich phase, and whose base material itself has high coercive force. The method includes: a hydrogen pulverization process (Step S1), in which coarse powder of a NdFeB system alloy is prepared by coarsely pulverizing a lump of NdFeB system alloy by making this lump occlude hydrogen; a fine pulverization process (Step S2), in which fine powder is prepared by performing fine pulverization for further pulverizing the coarse powder; a filling process (Step S3), in which the fine powder is put into a filling container; an orienting process (Step S4), in which the fine powder as held in the filling container is oriented; and a sintering process (Step S5), in which the fine powder after the orienting process is sintered as held in the filling container. The processes from hydrogen pulverization through orienting are performed with neither dehydrogenation heating nor evacuation each for desorbing hydrogen occluded in the hydrogen pulverization process. The processes from hydrogen pulverization through sintering are performed in an oxygen-free atmosphere.