R-FE-B SINTERED MAGNET AND PRODUCTION METHOD THEREFOR

This R-Fe-B sintered magnet has a main phase containing R(Fe,(Co))B intermetallic compound and a grain boundary phase, and is characterized in that: the inter-particle grain boundary of the grain boundary phase includes an expanded width part that is surrounded by a narrow width part at which the in...

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Bibliographic Details
Main Authors OHASHI, Tetsuya, HIROTA, Koichi, NAKAMURA, Hajime
Format Patent
LanguageEnglish
French
German
Published 20.09.2023
Subjects
ALLOYS
BASIC ELECTRIC ELEMENTS
CASTING
CHEMISTRY
ELECTRICITY
FERROUS OR NON-FERROUS ALLOYS
GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUSMETALS OR ALLOYS
INDUCTANCES
MAGNETS
MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS
MAKING METALLIC POWDER
MANUFACTURE OF ARTICLES FROM METALLIC POWDER
METALLURGY
METALLURGY OF IRON
MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS
PERFORMING OPERATIONS
POWDER METALLURGY
SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
TRANSFORMERS
TRANSPORTING
TREATMENT OF ALLOYS OR NON-FERROUS METALS
WORKING METALLIC POWDER
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Summary:This R-Fe-B sintered magnet has a main phase containing R(Fe,(Co))B intermetallic compound and a grain boundary phase, and is characterized in that: the inter-particle grain boundary of the grain boundary phase includes an expanded width part that is surrounded by a narrow width part at which the inter-particle width is 10 nm or less and that has a structure distended in the inter-particle width direction as compared with the grain boundary width of the narrow width part; the inter-particle width at the expanded width part is at least 30 nm; Fe/R which is the atomic ratio of Fe with respect to R in the expanded width part is 0.01-2.5; the main phase includes, in the surface part thereof, an HR-rich phase represented by (R',HR)(Fe,(Co))B (R' represents one or more elements that are selected from rare-earth elements including Y but excluding Dy, Tb, and Ho, and that essentially include Nd; and HR represents one or more elements selected from among Dy, Tb, and Ho); the contained amount of HR in the HR-rich phase is higher than that in the central part of the main phase. The R-Fe-B sintered magnet according to the present invention has a high magnetic coercive force even when the contained amount of Dy, Tb, and Ho is small.
Bibliography:Application Number: EP20170875271