WO2016143664A1 - Poudre magnétique à base de mnbi, son procédé de production, composé pour aimants liés, aimant lié et aimant métallique - Google Patents

Poudre magnétique à base de mnbi, son procédé de production, composé pour aimants liés, aimant lié et aimant métallique Download PDF

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WO2016143664A1
WO2016143664A1 PCT/JP2016/056609 JP2016056609W WO2016143664A1 WO 2016143664 A1 WO2016143664 A1 WO 2016143664A1 JP 2016056609 W JP2016056609 W JP 2016056609W WO 2016143664 A1 WO2016143664 A1 WO 2016143664A1
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mnbi
powder
hexagonal
magnet
magnetic powder
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PCT/JP2016/056609
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English (en)
Japanese (ja)
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信宏 片山
森本　耕一郎
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戸田工業株式会社
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Priority to CN201680013880.3A priority Critical patent/CN107408438A/zh
Priority to JP2017505280A priority patent/JPWO2016143664A1/ja
Publication of WO2016143664A1 publication Critical patent/WO2016143664A1/fr

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C12/00—Alloys based on antimony or bismuth
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
    • H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
    • H01F1/06—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys in the form of particles, e.g. powder
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
    • H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
    • H01F1/06—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys in the form of particles, e.g. powder
    • H01F1/08—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys in the form of particles, e.g. powder pressed, sintered, or bound together
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F7/00—Magnets
    • H01F7/02—Permanent magnets [PM]

Definitions

  • the present invention relates to a MnBi-based magnetic powder, a manufacturing method thereof, a bonded magnet compound, a bonded magnet, and a metal magnet.
  • MnBi magnet powder Since MnBi magnet powder has relatively high saturation magnetization and large crystal magnetic anisotropy, it is expected to be industrially used as a magnet for various motors. However, the oxidation resistance is low, and there is a drawback in that saturation magnetization decreases due to rapid oxidative corrosion particularly in an atmosphere containing water. Therefore, in order to eliminate such drawbacks, methods of coating with a binding resin or using a rust inhibitor have been attempted.
  • Patent Document 1 proposes a method of adding another metal element.
  • Patent Document 2 proposes to improve the corrosion resistance by adding an alkaline earth metal such as Sr to MnBi magnetic powder.
  • Patent Document 3 proposes to adsorb a cationic activator or amphoteric activator containing nitrogen atoms such as amine, amide, imide, etc. to MnBi magnetic powder to prevent oxidative degradation and to suppress a decrease in saturation magnetization. ing.
  • JP-A-9-139304 JP 2001-257110 A Japanese Patent Laid-Open No. 9-7163
  • the present invention provides a MnBi-based magnetic powder that can maintain high saturation magnetization even when stored in a high-temperature, high-humidity environment for a long period of time, and a method for producing such a MnBi-based magnetic powder. For the purpose.
  • the present invention provides a bonded magnet that can maintain high saturation magnetization even when stored in a high-temperature and high-humidity environment for a long period of time, and a bonded magnet that can manufacture such a bonded magnet.
  • the purpose is to provide a compound.
  • Another object of the present invention is to provide a metal magnet that can maintain high saturation magnetization even when stored in a high temperature and high humidity environment for a long period of time.
  • the present invention includes a hexagonal MnBi magnetic phase, and the content of Zn in the hexagonal MnBi magnetic phase is 0.5 to 8% by mass.
  • An MnBi magnetic powder is provided.
  • the above MnBi magnetic powder contains 0.5 to 8% by mass of Zn in the hexagonal MnBi magnetic phase having low oxidation resistance. This is presumed to improve the oxidation resistance of the hexagonal MnBi magnetic phase in a high temperature and high humidity environment. As a result, the MnBi magnetic powder can maintain high saturation magnetization even when stored for a long time in a high temperature and high humidity environment.
  • the present invention provides a hexagonal MnBi magnetic material containing Zn by mixing MnBi alloy powder and Zn powder and heat-treating them at 280 to 380 ° C. in an inert gas atmosphere under vacuum or reduced pressure.
  • a method for producing an MnBi-based magnetic powder comprising a step of obtaining a MnBi-based magnetic powder containing a phase, wherein the content of Zn in the hexagonal MnBi magnetic phase is 0.5 to 8% by mass.
  • MnBi-based magnetic powder manufacturing method a mixture of MnBi alloy powder and Zn powder is heated to 280 to 380 ° C. in a vacuum or in an inert gas atmosphere under reduced pressure. Thereby, Zn is vaporized, Zn is diffused into the hexagonal MnBi magnetic phase, and a hexagonal MnBi magnetic phase having a Zn content of 0.5 to 8% by mass is obtained.
  • the hexagonal MnBi magnetic phase thus obtained is presumed to have improved oxidation resistance in a high temperature and high humidity environment.
  • the MnBi-based magnetic powder obtained by the above production method can maintain high saturation magnetization even when stored for a long time in a high temperature and high humidity environment.
  • the present invention provides a process for obtaining a MnBi-based magnetic powder containing a hexagonal MnBi magnetic phase containing Zn by performing heat treatment and pulverization of a quenched ribbon obtained by melting and quenching an MnBiZn alloy. And a method for producing MnBi-based magnetic powder, wherein the content of Zn in the hexagonal MnBi magnetic phase is 0.5 to 8% by mass.
  • MnBi magnetic powder having a Zn content of 0.5 to 8% by mass in the hexagonal MnBi magnetic phase is obtained by melting and quenching, followed by heat treatment and pulverization. Yes.
  • Such MnBi-based magnetic powder can maintain high saturation magnetization even when stored for a long time in a high temperature and high humidity environment.
  • Either heat treatment or pulverization may be performed first.
  • the heat treatment is preferably performed at 280 to 380 ° C. in an inert gas atmosphere.
  • the present invention provides a bonded magnet compound comprising a kneaded material containing the above-described MnBi-based magnetic powder and a resin binder, and a bonded magnet including the above-described MnBi-based magnetic powder and a resin binder. . Since such a compound and bond magnet contain the MnBi magnetic powder having the above-described characteristics, high saturation magnetization can be maintained even if stored for a long time in a high temperature and high humidity environment.
  • the present invention includes a hexagonal MnBi magnetic phase containing Zn, and the content of Zn in the hexagonal MnBi magnetic phase is 0.5 to 8 mass relative to the total of Mn, Bi and Zn. %, Provide a metal magnet.
  • This metal magnet can be obtained by heat-treating or sintering a molded body produced by pressure-molding the above-described MnBi-based magnetic powder.
  • Such a metal magnet contains 0.5 to 8% by mass of Zn in a hexagonal MnBi magnetic phase having low oxidation resistance. This is presumed to improve the oxidation resistance of the hexagonal MnBi magnetic phase in a high temperature and high humidity environment. As a result, the metal magnet can maintain high saturation magnetization even if stored for a long time in a high temperature and high humidity environment.
  • the present invention it is possible to provide a MnBi-based magnetic powder capable of maintaining high saturation magnetization even when stored in a high-temperature and high-humidity environment for a long period of time, and a method for producing such MnBi-based magnetic powder.
  • the present invention also provides a bonded magnet that can maintain a high saturation magnetization even when stored in a high temperature and high humidity environment for a long period of time, and a bonded magnet compound capable of producing such a bonded magnet. Can do.
  • the present invention can provide a metal magnet that can maintain high saturation magnetization even when stored in a high temperature and high humidity environment for a long period of time.
  • FIG. 1A is an example of an electron micrograph showing an enlarged part of the cross section of the MnBi-based magnetic powder.
  • FIG. 1B is a diagram schematically showing a cross-sectional structure shown in the electron micrograph of FIG.
  • FIG. 2A is another example of an electron micrograph showing an enlarged part of a cross section of the MnBi-based magnetic powder.
  • FIG. 2B is a diagram showing a result of performing line analysis (EDX analysis) in the electron micrograph of FIG.
  • FIG. 3 is a flowchart showing a specific example of a method for producing an MnBi-based magnetic powder, a bonded magnet, and a metal magnet.
  • FIG. 1A is an example of an electron micrograph showing an enlarged part of the cross section of the MnBi-based magnetic powder.
  • FIG. 1B is a diagram schematically showing a cross-sectional structure shown in the electron micrograph of FIG.
  • FIG. 2A is another example of an electron micrograph showing an enlarged part of
  • FIG. 4 is a flowchart showing another specific example of a method for producing an MnBi-based magnetic powder, a bonded magnet, and a metal magnet.
  • FIG. 5 is a flowchart showing still another specific example of a method for producing an MnBi-based magnetic powder, a bond magnet, and a metal magnet.
  • FIG. 6 is a perspective view showing an embodiment of the MnBi-based metal magnet.
  • the MnBi magnetic powder of the present embodiment contains a hexagonal MnBi magnetic phase as a main component.
  • a hexagonal MnBi magnetic phase in addition to the hexagonal MnBi magnetic phase, at least one of a Bi phase and a Mn phase may be contained as a subcomponent.
  • the Mn phase is formed from Mn and Mn oxide.
  • the Bi phase is formed from Bi.
  • the total content of Mn and Bi in the MnBi magnetic powder may be, for example, 90% by mass or more, or 94% by mass or more.
  • the content ratio of Mn to the total of Mn and Bi is preferably 35 to 65 mol%, more preferably 37.5 to 50 mol%.
  • Mn the ratio of the hexagonal MnBi magnetic phase decreases, and the magnetization value tends to decrease.
  • the content ratio of Mn becomes too high, Bi is insufficient, the ratio of the hexagonal MnBi magnetic phase decreases, and the magnetization value tends to decrease.
  • the proportion of the Bi phase decreases, and the anisotropy in the heat treatment in the magnetic field tends to be insufficient.
  • excess Mn it will become easy to form MnZn and it exists in the tendency for Zn content in a MnBi magnetic phase to reduce.
  • the Zn content in the MnBi-based magnetic powder may be, for example, 0.3 to 5% by mass, or 0.4 to 4% by mass. Good.
  • the average particle diameter of the MnBi magnetic powder is, for example, 3 to 150 ⁇ m.
  • FIG. 1 (A) is an example of an electron micrograph showing an enlarged part of a cross section obtained by embedding a MnBi-based magnetic powder of the present embodiment in a resin and polishing it with a cross section polisher.
  • FIG. 1B is a diagram schematically showing a cross-sectional structure shown in the electron micrograph of FIG.
  • the MnBi-based magnetic powder contains a hexagonal MnBi magnetic phase 10 and a Bi phase 20 adjacent thereto. 1A and 1B also show the resin 30 used for embedding the MnBi magnetic powder.
  • the hexagonal MnBi magnetic phase 10 contains Zn in addition to Mn and Bi.
  • the content of Zn in the hexagonal MnBi magnetic phase 10 is 0.5 to 8% by mass, preferably 0.9 to 6% by mass.
  • excellent corrosion resistance tends to be impaired.
  • the Zn content is excessive, the nonmagnetic component increases and the magnetization value tends to decrease.
  • FIG. 2 (A) is another example of an electron micrograph showing an enlarged part of a cross section obtained by embedding the MnBi-based magnetic powder of the present embodiment in a resin and polishing it with a cross section polisher.
  • FIG. 2B is a diagram illustrating a result of performing line analysis (EDX analysis) along the line segment with the point a as a starting point in the electron micrograph of FIG.
  • EDX analysis line analysis
  • the MnBi-based magnetic powder contains a hexagonal MnBi magnetic phase 10 and Bi phases 20 and 20 so as to sandwich this.
  • the hexagonal MnBi magnetic phase 10 contains Mn, Bi, and Zn.
  • the Bi phase 20 is substantially free of Mn and Zn.
  • the hexagonal MnBi magnetism is maintained while keeping the ratio of nonmagnetic components low by allowing Zn to be unevenly distributed in the hexagonal MnBi magnetic phase 10 of the MnBi-based magnetic powder.
  • the corrosion resistance of the phase 10 can be effectively improved.
  • the Zn content in the Bi phase 20 is, for example, 0.01% by mass or less.
  • the Zn content in the Mn phase is, for example, 10% by mass or less.
  • the ratio of the hexagonal MnBi magnetic phase 10 in the MnBi-based magnetic powder may be, for example, 60 to 98% as an area ratio in a cross-sectional electron micrograph as shown in FIGS. 1 (A) and 2 (A). 70-95%. If the area ratio is too low, the ratio of the nonmagnetic phase tends to increase and the saturation magnetization value tends to decrease. On the other hand, if this area ratio becomes too high, for example, when the particles are larger than the size of the single magnetic domain, the Bi phase 20 that dissolves when the magnetic powder is obtained by performing the heat treatment in the magnetic field decreases. This tends to make it difficult for the hexagonal MnBi magnetic phase 10 to be oriented during heat treatment in a magnetic field. However, when the particles are substantially the same as the single magnetic domain size, the ratio of the hexagonal MnBi magnetic phase 10 may be high because it is not necessary to orient the hexagonal MnBi magnetic phase 10 within the particle.
  • the MnBi magnetic powder of this embodiment may be a magnet powder that has been heat-treated in a magnetic field.
  • the hexagonal MnBi magnetic phase has high oxidation resistance.
  • the MnBi-based magnetic powder can reduce the decrease in saturation magnetization even when stored for a long time in a high temperature and high humidity environment. Bond magnets and metal magnets formed using such MnBi-based magnetic powder can reduce the decrease in saturation magnetization even when stored for a long time in a high temperature and high humidity environment.
  • a method for producing an MnBi-based magnetic powder includes a step of obtaining an MnBi alloy powder, and heating a mixed powder containing the MnBi alloy powder and the Zn powder to 280 to 380 ° C. under reduced pressure to obtain a hexagonal MnBi Forming a magnetic phase and diffusing Zn inside the hexagonal MnBi magnetic phase to obtain a MnBi-based magnetic powder having a Zn content of 0.5 to 8 mass% in the hexagonal MnBi magnetic phase.
  • magnetic powder containing MnBi as a main component and Zn or the like as a subcomponent is referred to as MnBi-based magnetic powder in this specification.
  • MnBi alloy powder is obtained by (i) powder metallurgy method for obtaining MnBi alloy powder by crushing and sintering Mn and Bi, and (ii) obtaining MnBi alloy powder by melting and atomizing MnBi alloy.
  • Atomizing method (iii) Melting method to obtain MnBi alloy powder by pulverizing MnBi alloy lump obtained by melting in an arc furnace, (iv) Quenching the molten MnBi alloy with a roll, It can be manufactured using a liquid quenching method in which MnBi alloy powder is obtained by pulverization.
  • a chip, a shot, a powder, or the like can be appropriately selected and used as the Mn raw material and the Bi raw material.
  • a Zn raw material a chip, a shot, a powder, or the like can be appropriately selected and used.
  • the liquid quenching method (iv) is preferable.
  • an MnBi alloy powder having a sufficiently small particle size can be obtained by pulverizing a quenched ribbon obtained by quenching a molten alloy with a roll.
  • Zn can be sufficiently diffused into the hexagonal MnBi magnetic phase in the heat treatment step.
  • FIG. 3 is a flowchart showing a specific example of a method for producing MnBi-based magnetic powder, a compound for bonded magnet, a bonded magnet, and a metal magnet.
  • the MnBi alloy powder is prepared using the above (iv) liquid quenching method. That is, first, a Mn raw material and a Bi raw material are prepared, and a melting step S1 for melting (melting casting) the MnBi alloy by, for example, arc melting or the like is performed. Thereafter, a liquid quenching step S2 for obtaining a quenched ribbon by a liquid quenching method is performed. Subsequently, a coarse pulverization step S3 for coarsely pulverizing the obtained quenched ribbon is performed to obtain an MnBi alloy powder.
  • the MnBi alloy powder and the Zn powder obtained as described above are mixed.
  • the mixing ratio at this time is such that 1 to 10% by mass of Zn powder is mixed with MnBi alloy powder.
  • Zn powder since Zn powder is vaporized, it is preferable to mix more Zn powder than the Zn content of the target MnBi magnetic powder.
  • the mixed powder of the MnBi alloy powder and the Zn powder is 280 to 380 ° C. (preferably 300 to 370 ° C.) in vacuum or in an inert gas atmosphere under reduced pressure (preferably 10 Pa or less). Heat for 30-200 minutes.
  • the inert gas include argon gas and nitrogen gas.
  • the heating temperature under the above heating conditions is less than 280 ° C.
  • Zn is not sufficiently vaporized, so that the heat treatment step S5 tends to be long.
  • the hexagonal MnBi magnetic phase tends not to be generated sufficiently.
  • the heating temperature exceeds 380 ° C.
  • the structural phase transition of the hexagonal MnBi magnetic phase from the ferromagnetic low temperature phase to the paramagnetic high temperature phase occurs, and the ferromagnetism tends to disappear.
  • Bi dissolves and the Bi phase precipitates the ratio of the hexagonal MnBi magnetic phase tends to decrease and the saturation magnetization value tends to decrease.
  • the treatment time under the above heating conditions is too short, Zn diffusion does not proceed sufficiently, and a sufficient corrosion resistance improvement effect may not be obtained. Further, the hexagonal MnBi magnetic phase tends not to be generated sufficiently. On the other hand, if the treatment time is too long, the hexagonal MnBi magnetic phase grows and the coercive force tends to decrease.
  • the hexagonal MnBi magnetic phase in the MnBi-based magnetic powder obtained by the above-described manufacturing method has high oxidation resistance. For this reason, the MnBi-based magnetic powder can reduce the decrease in saturation magnetization even when stored for a long time in a high temperature and high humidity environment.
  • a magnetic field heat treatment step S6 is performed.
  • the magnetic field heat treatment step S6 is performed by heating the MnBi magnetic powder at a temperature of 260 to 380 ° C. for 30 to 600 minutes while applying a magnetic field of 0.4 to 0.8 T (4000 to 8000 G), for example. it can. By performing such a heat treatment step S6 in a magnetic field, anisotropic magnet powder can be obtained.
  • the heating temperature in the heat treatment step S6 in a magnetic field is too low, there is a tendency that it is difficult to be anisotropic enough. On the other hand, if the heating temperature is too high, a structural phase transition of the hexagonal MnBi magnetic phase from the ferromagnetic low temperature phase to the paramagnetic high temperature phase occurs, and the ferromagnetism tends to disappear. If the heating time in the heat treatment step S6 in the magnetic field is too short, there is a tendency that it is difficult to be anisotropic enough. On the other hand, it is sufficient that the heating time is about 600 minutes.
  • anisotropic magnet powder which has desired particle size by performing crushing process S7 after heat processing process S6 in a magnetic field.
  • the present invention is not limited to such a procedure.
  • the particles are reduced to a single domain size in the pulverization step S7 without performing the heat treatment step S6 in the magnetic field.
  • An anisotropic magnet powder may be obtained by pulverization.
  • an in-magnetic field forming step S8 is performed in which anisotropic magnet powder is formed in a magnetic field to produce a compact.
  • the applied magnetic field is, for example, 0.4 to 0.8 T (4000 to 8000 G), and the molding pressure is, for example, 1 to 10 t / cm 2 .
  • a heat treatment step S9 is performed in which the obtained molded body is heated at a temperature of 200 to 380 ° C. for 1 to 10 hours in an inert gas atmosphere.
  • a hot compression step of applying pressure while heating may be performed.
  • an anisotropic MnBi-based metal magnet can be manufactured.
  • the MnBi-based metal magnet obtained using the MnBi-based magnetic powder can maintain high saturation magnetization even when used in a high-temperature and high-humidity environment.
  • a molding step S20 is performed in which the MnBi-based magnetic powder is molded to produce a molded body.
  • the molding can be performed by a known method such as compression molding or injection molding at a molding pressure of 1 to 10 t / cm 2 .
  • the in-magnetic field sintering step S21 is performed using the obtained molded body. Thereby, an anisotropic MnBi-based metal magnet can be obtained. Sintering in a magnetic field can be performed by heating at a temperature of 280 to 380 ° C.
  • MnBi-based metal magnet obtained by this manufacturing method is also obtained using the MnBi-based magnetic powder, high saturation magnetization can be maintained even when used in a high temperature and high humidity environment.
  • a bonded magnet can be manufactured by performing a molding step S11 in which a compound for a bonded magnet obtained by kneading is molded in a magnetic field of, for example, 0.4 to 0.8 T (4000 to 8000 G).
  • the molding can be performed by a known method such as compression molding or injection molding at a molding pressure of 1 to 10 t / cm 2 .
  • the resin binder may be a thermosetting resin such as an epoxy resin.
  • the magnet powder and the resin binder are kneaded and molded by pressure molding or the like, and then a heat treatment is performed to manufacture a bonded magnet.
  • the bond magnet obtained by using the MnBi-based magnetic powder can suppress a decrease in saturation magnetization even when used in a high temperature and high humidity environment.
  • the manufacturing method of the MnBi-based magnetic powder of this embodiment is a method of melting and quenching a Mn raw material, a Bi raw material, and a Zn raw material, followed by a melt quenching method in which a rapidly cooled ribbon is obtained, and then subjecting the quenched ribbon to heat treatment and pulverization
  • a MnBi-based magnetic powder containing a hexagonal MnBi magnetic phase and having a Zn content of 0.5 to 8% by mass in the hexagonal MnBi magnetic phase is a method of melting and quenching a Mn raw material, a Bi raw material, and a Zn raw material.
  • FIG. 4 is a flowchart showing another specific example of a method for producing a MnBi magnetic powder and a method for producing a bonded magnet compound, a bonded magnet, and a metal magnet using the MnBi magnetic powder obtained by the production method.
  • a preparation step S31 for preparing a MnBi alloy by any one of the methods (i) to (iv) of the above embodiment is performed using a Mn raw material and a Bi raw material.
  • MnBiZn alloy an alloy containing MnBi as a main component and Zn or the like as a subcomponent.
  • the melting step S32 since a part of the evaporated Zn is scattered, it is preferable to add more Zn than the target Zn content of the MnBi-based magnetic powder. For example, 1 to 10% by mass of Zn is added to the MnBi alloy.
  • a liquid quenching step S33 for quenching the melted MnBiZn alloy by a melt quenching method and a coarse pulverizing step S34 are performed.
  • the quenched ribbon is roughly pulverized by a known method to obtain MnBi-based alloy powder.
  • This MnBi-based alloy powder is a nonmagnetic powder containing MnBi as a main component and Zn or the like as a subcomponent.
  • a heat treatment step S6 in a magnetic field and a pulverization step S7 can be performed to obtain an MnBi-based magnetic powder (magnet powder).
  • the heat treatment step S6 in the magnetic field and the pulverization step S7 can be performed in the same manner as the flowchart shown in FIG. In this case, the procedure is not limited to this.
  • the particles are made into a single domain size in the pulverization step S7 without performing the heat treatment step S6 in the magnetic field.
  • an anisotropic magnet powder is obtained after the hexagonal MnBi magnetic phase is sufficiently generated in the heat treatment step S5, the particles are made into a single domain size in the pulverization step S7 without performing the heat treatment step S6 in the magnetic field.
  • the MnBi-based metal magnet can be manufactured by performing the forming step S8 in the magnetic field and the heat treatment step S9 in the same manner as the flowchart shown in FIG.
  • the MnBi-based metal magnet may be manufactured by performing the molding step S20 and the magnetic field sintering step S21 using the MnBi-based magnetic powder.
  • the bonded magnet may be manufactured by performing the kneading step S10 and the forming step S11 using the MnBi-based magnetic powder and the resin binder.
  • the hexagonal MnBi magnetic phase in the MnBi magnetic powder obtained by this production method has high oxidation resistance. For this reason, the MnBi-based magnetic powder can reduce the decrease in saturation magnetization even when stored for a long time in a high temperature and high humidity environment.
  • FIG. 5 is a flowchart showing still another specific example of a method for producing a MnBi-based magnetic powder and a method for producing a compound for a bonded magnet, a bonded magnet, and a metal magnet using the MnBi-based magnetic powder obtained by this manufacturing method. is there.
  • the heat treatment step S34 is performed after the preparation step S31, the dissolution step S32, and the liquid quenching step S33, as in the flowchart shown in FIG.
  • the quenched ribbon after liquid quenching is heated at 280 to 380 ° C. (preferably 300 to 370 ° C.) for 30 to 200 minutes in an inert gas atmosphere.
  • the heat treatment step S34 may be performed, for example, in an inert gas atmosphere under a reduced pressure of 10 Pa or less, or in a vacuum.
  • an MnBi-based alloy having a hexagonal MnBi magnetic phase containing a predetermined amount of Zn is obtained.
  • the MnBi magnetic powder can be obtained.
  • each powder is pulverized using a ball mill or the like until it reaches a single magnetic domain level of about 10 ⁇ m (single crystal size). If pulverized to this extent, anisotropic MnBi magnet powder can be obtained without applying a magnetic field.
  • the MnBi metal magnet can be obtained by performing the forming step S8 in the magnetic field and the heat treatment step S9. Similar to the flowchart shown in FIG. 4, the MnBi-based metal magnet and the bonded magnet can be manufactured by performing the steps in the magnetic field forming step S8 or the kneading step S10 and the subsequent steps.
  • FIG. 6 is a perspective view of the MnBi-based metal magnet 50.
  • the shape of the MnBi-based metal magnet is not limited to the cylindrical shape as shown in FIG. 6, and may be, for example, a prismatic shape or a spherical shape.
  • the bonded magnet may also have a cylindrical shape as shown in FIG. 6, a prismatic shape, or a spherical shape.
  • the composition of the MnBi-based metal magnet 50 includes a hexagonal MnBi magnetic phase containing Zn.
  • the content of Zn in the hexagonal MnBi magnetic phase is 0.5 to 8% by mass with respect to the total of Mn, Bi and Zn. This content may be, for example, 0.3 to 5% by mass or 0.4 to 4% by mass from the viewpoint of improving corrosion resistance while maintaining high magnetic properties.
  • the contents of Mn, Bi and Zn in the hexagonal MnBi magnetic phase of the MnBi-based metal magnet 50 may be the same as those described in the embodiment of the MnBi-based magnetic powder.
  • the MnBi-based metal magnet 50 can be obtained by heat-treating or sintering a molded body produced by pressure-molding the above-described MnBi-based magnetic powder.
  • the compound for bond magnet is composed of a kneaded product of the above-described MnBi-based magnetic powder and a resin binder.
  • the bonded magnet is obtained by molding such a bonded magnet compound.
  • the bonded magnet includes the MnBi-based magnetic powder and the resin binder according to the above-described embodiment.
  • the composition of the bonded magnet compound and the MnBi-based magnetic powder contained in the bonded magnet may be the same as described in the above embodiment.
  • Example 1 ⁇ Production of magnet powder>
  • the Mn chip and Bi shot were melted in an arc melting furnace to prepare a MnBi alloy.
  • 5 g of the MnBi alloy obtained in the arc melting furnace was put into a hot water discharge nozzle of a transparent quartz tube having an orifice diameter of ⁇ 0.45 mm at the bottom. After evacuating the chamber of the liquid quenching apparatus, the MnBi alloy in the hot water nozzle was melted by high frequency melting in an argon gas atmosphere of 50 kPa.
  • a MnBi molten metal was sprayed onto a copper roll at a molten metal injection pressure of 10 kPa to obtain a quenched ribbon.
  • the rotational speed of the roll was 20 m / s, and the distance between the roll and the hot water nozzle was 0.4 mm.
  • the obtained quenched ribbon was pulverized to obtain a MnBi alloy powder having a particle size of 150 ⁇ m or less.
  • a mixed powder was prepared by mixing Zn powder (3.0% by mass) with MnBi alloy powder (100% by mass).
  • the mixed powder was heat-treated in an inert gas (nitrogen gas) atmosphere of 10 Pa or less at a temperature of 320 ° C. for 120 minutes to diffuse Zn into MnBi.
  • the temperature at this time is shown as “heat treatment temperature” in Table 1.
  • an MnBi magnetic powder was obtained.
  • MnBi magnetic powder is subjected to heat treatment in a magnetic field in which a magnetic field of 0.6 T (6000 G) is applied, and the magnet powder is obtained. Obtained.
  • Example 2 A magnetic powder was obtained by preparing a MnBi magnetic powder in the same manner as in Example 1 except that a mixed powder was prepared by mixing a Zn powder (5.0% by mass) with an MnBi alloy powder (100% by mass). It was. Evaluations 1 and 2 were performed in the same manner as in Example 1. The evaluation results are as shown in Tables 1 and 2.
  • Example 3 A magnetic powder was obtained by preparing a MnBi magnetic powder in the same manner as in Example 1 except that the temperature during heat treatment of the mixed powder was 360 ° C. Evaluations 1 and 2 were performed in the same manner as in Example 1. The evaluation results are as shown in Tables 1 and 2.
  • Example 4 A magnetic powder was obtained by preparing a MnBi magnetic powder in the same manner as in Example 3 except that a mixed powder was prepared by mixing a Zn powder (5.0 mass%) with an MnBi alloy powder (100 mass%). It was. The magnet powder was evaluated in the same manner as in Example 3. The evaluation results are as shown in Tables 1 and 2.
  • Example 6 The Mn chip and Bi shot were melted in an arc melting furnace to prepare a MnBi alloy.
  • 1% by mass of Zn was added to the MnBi alloy (100% by mass) obtained in the arc melting furnace, and again melted in the arc melting furnace.
  • 5 g of the obtained MnBiZn alloy was put into a hot water nozzle of a transparent quartz tube having an orifice diameter of ⁇ 0.45 mm at the bottom.
  • the MnBiZn alloy in the hot water nozzle was melted by high-frequency melting in an argon gas atmosphere of 50 kPa. Then, a MnBiZn molten metal was sprayed onto a copper roll at a molten metal injection pressure of 10 kPa to obtain a quenched ribbon.
  • the rotational speed of the roll was 20 m / s, and the distance between the roll and the hot water nozzle was 0.4 mm.
  • the obtained quenched ribbon was coarsely pulverized to obtain a MnBi alloy powder having a particle size of 150 ⁇ m or less.
  • MnBi-based alloy powder is subjected to heat treatment in a magnetic field in which a magnetic field of 0.6 T (6000 G) is applied, and MnBi-based magnetic powder ( Magnet powder) was obtained.
  • Table 1 shows the temperature of the heat treatment in the magnetic field at this time. Evaluations 1 and 2 were performed in the same manner as in Example 1. The evaluation results are as shown in Tables 1 and 2.
  • Example 7 A MnBi-based alloy powder was prepared in the same manner as in Example 6 except that 2% by mass of Zn was added to the MnBi alloy (100% by mass) obtained in the arc melting furnace to obtain a magnet powder. Evaluations 1 and 2 were performed in the same manner as in Example 1. The evaluation results are as shown in Tables 1 and 2.
  • Example 8 In the same manner as in Example 6, a MnBiZn molten metal was sprayed onto the roll to obtain a quenched ribbon.
  • the quenched ribbon was heat treated (atmosphere: argon gas, temperature: 300 ° C., time: 240 minutes). This heat treatment was performed in an inert gas atmosphere of 10 Pa or less. Table 1 shows the temperature of the heat treatment at this time.
  • the quenched ribbon was pulverized using a ball mill (conditions: 50 rpm, 2 hours) until the particle size became 63 ⁇ m or less to obtain MnBi-based magnetic powder (magnet powder). The average particle size of the magnet powder was 15 ⁇ m.
  • Evaluations 1 and 2 were performed in the same manner as in Example 1. The evaluation results are as shown in Tables 1 and 2.
  • Example 1 A magnetic powder was obtained by preparing a MnBi magnetic powder in the same manner as in Example 1 except that the Zn powder was not mixed. Evaluations 1 and 2 were performed in the same manner as in Example 1. The evaluation results are as shown in Tables 1 and 2.
  • Example 2 A magnetic powder was obtained by preparing a MnBi magnetic powder in the same manner as in Example 1 except that a mixed powder was prepared by mixing a Zn powder (8.0% by mass) with MnBi alloy powder (100% by mass). It was. Evaluations 1 and 2 were performed in the same manner as in Example 1. The evaluation results are as shown in Tables 1 and 2.
  • Table 2 shows the saturation magnetization deterioration rate calculated by the following equation from the values of saturation magnetization before and after storage for 4 days in air at a temperature of 40 ° C. and a relative humidity of 50%.
  • Saturation magnetization deterioration rate (%) 100 ⁇ [saturation magnetization after storage] / [saturation magnetization before storage] ⁇ 100
  • the Zn content (2) of the magnet powder of each example was in the range of 0.5 to 8% by mass.
  • the magnet powder of each example had a saturation magnetization deterioration rate of 5% or less even after being stored in air at a temperature of 40 ° C. and a relative humidity of 50% for 4 days.
  • oxygen content was 3000 ppm or less. From this, it was confirmed that the magnet powders of the respective examples contain a predetermined amount of Zn in the hexagonal MnBi magnetic phase, thereby suppressing oxidative deterioration and reducing the deterioration rate of saturation magnetization.
  • Comparative Example 1 since the hexagonal MnBi magnetic phase did not contain Zn, it was confirmed that the deterioration rate of saturation magnetization increased due to the progress of oxidation deterioration.
  • the oxygen content of the magnet powder of Comparative Example 1 was higher than that of the example.
  • the saturation magnetization deterioration rate of Examples 1, 6, 7, and 8 when stored under condition (1) is 15% or less, and the saturation magnetization deterioration rate is significantly higher than that of Comparative Example 1. It was getting smaller.
  • the deterioration rate of saturation magnetization of Examples 1, 6, 7, and 8 when stored under the condition (2) is 20% or less, and the deterioration rate of saturation magnetization is significantly higher than that of Comparative Example 1. It was getting smaller.
  • Example 9 Comparative Examples 3 to 12
  • Magnet powder was obtained in the same manner as in Example 6 except that the elements added to the MnBi alloy were as shown in Table 5.
  • a magnetic powder was prepared by heat-treating MnBi alloy powder containing no additive element under the same conditions as in Example 6 (Comparative Example 3).
  • the prepared magnet powder was stored at normal temperature (about 20 ° C.) in the air.
  • the saturation sample (4 ⁇ I max ), residual magnetic flux density (Br), and coercive force (Hcj) before storage and after storage (after 4 days and 15 days) were measured using a vibrating sample magnetometer (VSM: VSM manufactured by Toei Industry Co., Ltd.). -5 type). Table 5 shows the measurement results.
  • the magnet powder of Example 9 to which Zn was added had high saturation magnetization even after storage for 15 days. That is, it was confirmed that by using Zn, oxidation is sufficiently suppressed and high saturation magnetization can be maintained.
  • Comparative Examples 9 to 12 since the saturation magnetization at the initial stage (before storage) was too low, evaluation after storage was not performed.
  • the present invention it is possible to provide a MnBi-based magnetic powder capable of maintaining high saturation magnetization even when stored in a high-temperature and high-humidity environment for a long period of time, and a method for producing such MnBi-based magnetic powder.
  • the present invention also provides a bonded magnet that can maintain high saturation magnetization even when stored in a high temperature and high humidity environment for a long period of time, a compound for bonded magnet that can produce such a bonded magnet, and a metal magnet. Can be provided.

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Abstract

L'invention concerne une poudre magnétique à base de MnBi qui contient une phase magnétique de MnBi hexagonale, et dans laquelle la teneur en Zn dans la phase magnétique de MnBi hexagonale est de 0,5 à 8 % en masse. L'invention concerne également un aimant lié qui contient cette poudre magnétique à base de MnBi et un liant résineux. L'invention concerne également un aimant métallique qui contient une phase magnétique de MnBi hexagonale contenant du Zn, et dans lequel la teneur en Zn par rapport à la teneur totale en Mn, Bi et Zn dans la phase magnétique de MnBi hexagonale est de 0,5 à 8 % en masse.
PCT/JP2016/056609 2015-03-06 2016-03-03 Poudre magnétique à base de mnbi, son procédé de production, composé pour aimants liés, aimant lié et aimant métallique WO2016143664A1 (fr)

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CN201680013880.3A CN107408438A (zh) 2015-03-06 2016-03-03 MnBi系磁性粉末以及其的制造方法、以及粘结磁体用混合物、粘结磁体、以及金属磁体
JP2017505280A JPWO2016143664A1 (ja) 2015-03-06 2016-03-03 ＭｎＢｉ系磁性粉末及びその製造方法、並びに、ボンド磁石用コンパウンド、ボンド磁石、及び金属磁石

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08138921A (ja) * 1994-04-14 1996-05-31 Hitachi Maxell Ltd 磁性粉末およびその製造方法、並びにこの製造方法で得られた磁性粉末を用いた磁気記録媒体とこの磁気記録媒体の記録再生方法および記録再生装置
JPH1167511A (ja) * 1997-08-11 1999-03-09 Hitachi Maxell Ltd 磁気材料
JP2000040611A (ja) * 1998-07-23 2000-02-08 Hitachi Maxell Ltd 樹脂結合型永久磁石材料、これを利用したエンコーダ、および樹脂結合型永久磁石材料の着磁方法

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CN1149174A (zh) * 1995-06-19 1997-05-07 日立马库塞鲁株式会社 磁记录载体以及其记录、重写的方法
JP3490201B2 (ja) * 1995-11-14 2004-01-26 日立マクセル株式会社 ＭｎＮｉＢｉ合金磁性粉末
JP2001257110A (ja) * 2000-03-09 2001-09-21 Hitachi Maxell Ltd 磁性材料と、これを利用した磁気記録媒体

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08138921A (ja) * 1994-04-14 1996-05-31 Hitachi Maxell Ltd 磁性粉末およびその製造方法、並びにこの製造方法で得られた磁性粉末を用いた磁気記録媒体とこの磁気記録媒体の記録再生方法および記録再生装置
JPH1167511A (ja) * 1997-08-11 1999-03-09 Hitachi Maxell Ltd 磁気材料
JP2000040611A (ja) * 1998-07-23 2000-02-08 Hitachi Maxell Ltd 樹脂結合型永久磁石材料、これを利用したエンコーダ、および樹脂結合型永久磁石材料の着磁方法

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