PROCESS FOR PRODUCTION OF SURFACE-MODIFIED RARE EARTH SINTERED MAGNETS AND SURFACE-MODIFIED RARE EARTH SINTERED MAGNETS

The invention provides a rare earth sintered magnet which is improved in corrosion resistance by oxidizing heat treatment to such a level as to exhibit satisfactory corrosion resistance even in an atmosphere of varying humidity and which is reduced in the deterioration of magnetic characteristics du...

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Bibliographische Detailangaben
Hauptverfasser:	KIKUGAWA ATSUSHI, FUJIHARA MAHORO, YOSHIMURA KOSHI
Format:	Patent
Sprache:	eng ; kor
Schlagworte:	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
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Beschreibung
Zusammenfassung:	The invention provides a rare earth sintered magnet which is improved in corrosion resistance by oxidizing heat treatment to such a level as to exhibit satisfactory corrosion resistance even in an atmosphere of varying humidity and which is reduced in the deterioration of magnetic characteristics due to oxidizing heat treatment and a process for the production of the magnet. A surface-modified rare earth sintered magnet characterized in that the surface modified part is an at least three-layered surface modification layer which comprises a main layer containing R, Fe, B and oxygen, an amorphous layer containing at least R, Fe and oxygen, and an outermost layer containing hematite-base iron oxide as the main constituent in this order from the inside of the magnet; and a process for the production of the magnet, characterized by comprising the step of subjecting a magnet body to heat treatment in an atmosphere of oxygen partial pressure of 1 × 10to 1 × 10Pa and water vapor partial pressure of 0.1 to 1000Pa (exclusive of 1000Pa) at 200 to 600°C.