PERMANENT MAGNET AND PROCESS FOR PRODUCING THE SAME

• Main Authors: MUKAE, ICHIROU, ITOU, MASAMI, KATOU, TAKEO, NAKAMURA, KYUZO, NAKATSUKA, ATSUSHI, NAGATA, HIROSHI, YOSHIIZUMI, RYOU, SHINGAKI, YOSHINORI
• Format: Patent
• Language: English; French; Japanese
• Published: 20.03.2008
• Subjects: BASIC ELECTRIC ELEMENTS; CHEMICAL SURFACE TREATMENT; CHEMISTRY; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATIONOR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY IONIMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING MATERIAL WITH METALLIC MATERIAL; COATING METALLIC MATERIAL; DIFFUSION TREATMENT OF METALLIC MATERIAL; ELECTRICITY; INDUCTANCES; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; MAGNETS; METALLURGY; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THESURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; TRANSFORMERS

A permanent magnet obtained through forming of a film of Dy and/or Tb on a surface of iron-boron-rare earth sintered magnet with given configuration and diffusion thereof in crystal grain boundary phase, which permanent magnet has an enhanced coercive force. There is provided a process for producing a permanent magnet, comprising the film forming step of evaporating a metal evaporation material containing at least either Dy or Tb and adhering evaporated metal molecules onto a surface of iron-boron-rare earth sintered magnet; and the diffusion step of diffusing the metal atoms having been adhered to the surface by heat treatment into the crystal grain boundary phase of the sintered magnet, wherein the metal evaporation material contains at least either Nd or Pr. L'invention concerne un aimant permanent obtenu par la formation d'un film de Dy et/ou de Tb sur la surface d'un aimant fritté en terres rares fer-bore avec une configuration donnée et une diffusion de celui-ci dans la phase de limite des grains cristallins, cet aimant permanent possédant une force coercitive renforcée. Cette invention concerne aussi le processus de production d'aimant permanent, comprenant l'étape de formation de film qui consiste à évaporer un matériau d'évaporation métallique contenant Dy ou Tb au moins et à coller des molécules métalliques évaporées sur une surface d'aimant fritté en terres rares fer-bore, et l'étape de diffusion qui consiste à diffuser des atomes métalliques collés à la surface par un traitement thermique dans la phase de limites des grains cristallins de l'élément fritté, ce matériau d'évaporation métallique contenant Nd ou Pr au moins.