ANISOTROPIC RARE EARTH SINTERED MAGNET AND METHOD FOR PRODUCING SAME

• Main Authors: NOMURA, Tadao, OTSUKA, Kazuki, KAMATA, Masayuki
• Format: Patent
• Language: English; French; German
• Published: 08.02.2023
• 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

Provided is an anisotropic rare earth sintered magnet represented by the formula (R1-aZra)x(Fe1-bCob)100-x-y(M11-cM2c)y (wherein R is at least one element selected from rare earth elements and Sm is essential; M1 is at least one element selected from the group consisting of V, Cr, Mn, Ni, Cu, Zn, Ga, Al, and Si; M2 is at least one element selected from the group consisting of Ti, Nb, Mo, Hf, Ta, and W; x, y, a, b, and c each satisfy 7 ≤ x ≤ 15 at%, 4 ≤ y ≤ 20 at%, 0 ≤ a ≤ 0.2, 0 ≤ b ≤ 0.5, and 0 ≤ c ≤ 0.9). The anisotropic rare earth sintered magnet includes 80% by volume or more of a main phase composed of a compound of a ThMn12 type crystal, the main phase having an average crystal grain size of 1 pm or more, and an intergranular grain boundary phase being formed between adjacent main phase grains. Also provided is a method for producing the anisotropic rare earth sintered magnet, including pulverizing an alloy containing a compound phase of a ThMn12 type crystal; compacting the pulverized alloy under application of a magnetic field to form a compact; and then sintering the compact at a temperature of 800°C or higher and 1400°C or lower. According to the present invention, it is possible to provide an anisotropic rare earth sintered magnet having a compound of a ThMn12 type crystal as a main phase and exhibiting good magnetic properties, and a method for producing the same.