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WO2018193900A1 - Matériau magnétique composite, moteur et procédé de production de matériau magnétique composite - Google Patents

Matériau magnétique composite, moteur et procédé de production de matériau magnétique composite Download PDF

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Publication number
WO2018193900A1
WO2018193900A1 PCT/JP2018/014945 JP2018014945W WO2018193900A1 WO 2018193900 A1 WO2018193900 A1 WO 2018193900A1 JP 2018014945 W JP2018014945 W JP 2018014945W WO 2018193900 A1 WO2018193900 A1 WO 2018193900A1
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Prior art keywords
magnetic material
composite
composite magnetic
particles
soft magnetic
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English (en)
Japanese (ja)
Inventor
笹栗　大助
西村　直樹
達夫 岸川
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Canon Inc
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Canon Inc
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Priority claimed from JP2018023556A external-priority patent/JP2018182302A/ja
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G49/00—Compounds of iron
    • C01G49/02—Oxides; Hydroxides
    • C01G49/06—Ferric oxide [Fe2O3]
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G49/00—Compounds of iron
    • C01G49/02—Oxides; Hydroxides
    • C01G49/08—Ferroso-ferric oxide [Fe3O4]
    • 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
    • H01F1/09—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 mixtures of metallic and non-metallic particles; metallic particles having oxide skin
    • 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
    • H01F1/10—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 non-metallic substances, e.g. ferrites, e.g. [(Ba,Sr)O(Fe2O3)6] ferrites with hexagonal structure
    • H01F1/11—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 non-metallic substances, e.g. ferrites, e.g. [(Ba,Sr)O(Fe2O3)6] ferrites with hexagonal structure in the form of particles
    • 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

Definitions

  • the present invention relates to a composite magnetic material, a motor, and a method for manufacturing the composite magnetic material.
  • a neodymium magnet As a high-performance magnet, a neodymium magnet (composition: Nd 2 Fe 14 B or the like) is known. Neodymium magnets are widely used because of their large residual magnetic flux density and coercive force.
  • Neodymium magnets contain neodymium, a rare earth element, as an essential component. Since rare earth elements are expensive and may be unstable in supply, there is a demand for suppressing the amount of rare earth elements used. Therefore, attempts have been made to produce high-performance magnets while suppressing the amount of rare earth elements used.
  • Patent Document 1 JP 2011-35006 A discloses a hard magnetic phase core containing epsilon iron oxide ( ⁇ -Fe 2 O 3 ), alpha iron ( ⁇ -Fe), and at least one of the cores.
  • ⁇ -Fe 2 O 3 epsilon iron oxide
  • ⁇ -Fe alpha iron
  • Patent Document 1 JP 2011-35006 A discloses a hard magnetic phase core containing epsilon iron oxide ( ⁇ -Fe 2 O 3 ), alpha iron ( ⁇ -Fe), and at least one of the cores.
  • a core-shell type magnetic material having a soft magnetic phase shell covering the portion is described.
  • ⁇ -Fe 2 O 3 is used as a hard magnetic phase having a high coercive force
  • ⁇ -Fe is used as a soft magnetic phase having a high saturation magnetic flux density, and both are magnetically coupled by an exchange coupling action.
  • a composite magnet is manufactured.
  • iron or iron alloy may be exposed on the surface of the magnetic material. This is particularly noticeable when iron or an iron alloy is used as a shell of a core-shell type magnetic material as described in Patent Document 1.
  • Iron and iron alloys are easily oxidized by air and moisture. Therefore, if the iron or iron alloy constituting the magnetic material is exposed on the surface, it is oxidized by air or moisture, and the magnetic properties of the magnetic material are deteriorated. That is, the composite magnetic material containing iron or an iron alloy has a problem of low stability over time.
  • an object of the present invention is to provide a magnetic material having high temporal stability, which is a composite magnetic material containing iron or an iron alloy.
  • a composite magnetic material as one aspect of the present invention is a composite magnetic material containing a soft magnetic material and a hard magnetic material, wherein the soft magnetic material contains iron or an iron alloy, and at least a surface of the soft magnetic material A part is covered with crystalline iron oxide.
  • the composite magnetic material according to the present embodiment includes a soft magnetic material and a hard magnetic material, the soft magnetic material includes iron or an iron alloy, and at least a part of the surface of the soft magnetic material is coated with crystalline iron oxide. Has been.
  • the “soft magnetic material” refers to a material having a small coercive force and a large saturation magnetic flux density.
  • hard magnetic material refers to a material having a large coercive force.
  • the composite magnetic material according to the present embodiment has a fine structure in which two phases of a soft magnetic material phase (soft magnetic phase) and a hard magnetic material phase (hard magnetic phase) are adjacent to each other in the order of nm (nanometer).
  • a fine mixed structure By having such a fine mixed structure, an exchange coupling action can be exerted between the soft magnetic phase and the hard magnetic phase.
  • an exchange coupling action is acting between the soft magnetic phase and the hard magnetic phase, when the switching magnetic field is applied, the magnetization reversal of the soft magnetic phase is suppressed by the magnetization of the exchanged hard magnetic phase.
  • the magnetization curve behaves as if the soft magnetic phase and the hard magnetic phase are single-phase magnets due to the exchange coupling action.
  • BH high energy product
  • FIG. 1 is a diagram schematically showing a structural example of a composite magnetic material according to the first embodiment.
  • the composite magnetic material 101 according to the present embodiment has a sea-island structure having an island portion containing a hard magnetic material H in a sea portion containing a soft magnetic material S.
  • the composite magnetic material 101 includes crystalline iron oxide O that covers at least a part of the surface of the soft magnetic material S.
  • the soft magnetic material S includes iron or an iron alloy.
  • the soft magnetic material S preferably contains ⁇ -Fe (alpha iron) or an FeM alloy.
  • M represents at least one element selected from the group consisting of Co, Ni, Al, Ga, and Si, and the composition ratio of each element in the FeM alloy can be arbitrarily selected.
  • the soft magnetic material S preferably contains ⁇ -Fe, and is particularly preferably made of ⁇ -Fe. Note that the iron or iron alloy included in the soft magnetic material S does not necessarily have crystallinity.
  • the soft magnetic material S is a material having a saturation magnetic flux density larger than that of the hard magnetic material H.
  • the saturation magnetic flux density of the soft magnetic material S is not particularly limited, but is preferably 50 emu / g or more, and more preferably 100 emu / g or more.
  • the hard magnetic material H is a material having a larger coercive force than the soft magnetic material S.
  • the coercive force of the hard magnetic material H is not particularly limited, but is preferably 500 Oe or more, and more preferably 1000 Oe or more.
  • the hard magnetic material H preferably contains ⁇ -Fe 2 O 3 (epsilon iron oxide). Since ⁇ -Fe 2 O 3 is a material having a particularly large coercive force among iron-based oxide materials, the hard magnetic material H contains ⁇ -Fe 2 O 3 , so that the energy product of the composite magnetic material 101 ( BH) max can be further increased.
  • ⁇ -Fe 2 O 3 epsilon iron oxide
  • hard magnetic material H comprises ⁇ -Fe 2 O 3
  • a portion of the Fe atoms in the ⁇ -Fe 2 O 3 may be substituted by other metal elements.
  • a part of Fe atoms in ⁇ -Fe 2 O 3 may be substituted with at least one element selected from the group consisting of Co, Ni, Al, and Ga.
  • the content of ⁇ -Fe 2 O 3 in the hard magnetic material H is preferably 100 vol% or less than 50 vol%, 70 vol% More preferably, it is 100 volume% or less.
  • the crystalline iron oxide O covers at least a part of the surface of the soft magnetic material S.
  • the crystalline iron oxide O preferably covers 50% to 100% of the surface of the soft magnetic material S, more preferably 70% to 100%, more preferably 90% to 100%. % Or less is particularly preferred.
  • the surface of the soft magnetic material S here refers to the surface portion of the soft magnetic material S exposed to the outside in a state where the crystalline iron oxide O is removed.
  • the above-mentioned “surface of the soft magnetic material S” can be rephrased as “the surface of the sea part”.
  • the soft magnetic material S contains iron or an iron alloy as described above, it is easily oxidized or corroded by oxygen, moisture, etc. in the atmosphere when placed in contact with the atmosphere. The characteristics will deteriorate.
  • the saturation magnetic flux density of the soft magnetic material S decreases, the saturation magnetic flux of the composite magnetic material 101 as a whole.
  • the coercive force also decreases because the exchange coupling force decreases.
  • at least a part of the surface of the soft magnetic material S is covered with crystalline iron oxide O. Crystalline iron oxide O acts as a protective layer and can suppress the oxidation or corrosion of the soft magnetic material S. Thereby, the fall of the magnetic characteristic of the soft magnetic material S can be suppressed, and the temporal stability of the composite magnetic material 101 can be improved.
  • the crystalline iron oxide O preferably forms a dense film that covers the surface of the soft magnetic material S. Thereby, the penetration
  • the thickness of the crystalline iron oxide O is preferably 5 nm or more and 500 nm or less, more preferably 5 nm or more and 200 nm or less, and further preferably 5 nm or more and 100 nm or less.
  • the thickness of the crystalline iron oxide O is preferably 5 nm or more and 500 nm or less, more preferably 5 nm or more and 200 nm or less, and further preferably 5 nm or more and 100 nm or less.
  • the crystalline iron oxide O is not particularly limited as long as it has crystallinity, but is preferably Fe 3 O 4 (magnetite).
  • Fe 3 O 4 has a particularly high effect of blocking the intrusion of oxygen and moisture in the atmosphere among crystalline iron oxides, and can suppress the deterioration of the magnetic properties of the soft magnetic material S more effectively.
  • ⁇ -Fe (alpha iron) or an FeM alloy is preferably used as the soft magnetic material S, but Fe 3 O 4 which is crystalline iron oxide O obtained by oxidizing this from the surface. (Magnetite) also functions as a soft magnetic material. Therefore, the crystalline iron oxide O has a function of protecting the soft magnetic material S and suppressing oxidation or corrosion, and magnetically couples with the hard magnetic material H, thereby exhibiting magnetic properties as a whole of the composite magnetic material. It also has a function to When a protective layer for suppressing oxidation is formed on the surface with silica or resin as in the past, silica and resin do not have a function as a magnetic material, so the magnetic characteristics of the composite magnetic material as a whole are large. It will decline.
  • the protective layer can also have a function as a magnetic material, and a composite magnetic material having a high stability over time can be realized without greatly degrading the magnetic properties of the entire composite magnetic material. can do.
  • the composite magnetic material 101 includes not only the soft magnetic material S that contains iron or an iron alloy and is easily oxidized or corroded, but also is typically an oxide that is hard to be oxidized or corroded. H is also included. Therefore, the progress of oxidation and corrosion is slower than in the case of a magnetic material composed of only the soft magnetic material S that is easily oxidized or corroded. As a result, a composite magnetic material with high stability over time can be realized even with crystalline iron oxide O having a relatively thin thickness of 5 nm to 500 nm as described above.
  • the softness can be increased. Only the vicinity of the outermost surface of the magnetic material S can be efficiently oxidized. Therefore, the crystallinity of the crystalline iron oxide O to be formed and the denseness of the film can be further increased, and a composite magnetic material having high transit stability can be realized.
  • the content of the Nd element is preferably 0% by mass or more and 3% by mass or less, and 0% by mass or more. More preferably, it is 1 mass% or less. It is particularly preferable that the composite magnetic material 101 does not substantially contain an Nd element. Thus, the cost of the composite magnetic material 101 can be reduced by reducing the content of the Nd element in the composite magnetic material 101.
  • the composite magnetic material 101 according to the present embodiment has a sea-island structure having a sea part including the soft magnetic material S and an island part including the hard magnetic material H.
  • the sea portion includes the soft magnetic material S and the island portion includes the hard magnetic material H.
  • the sea portion includes the hard magnetic material H and the island portion includes the soft magnetic material S. Good.
  • the soft magnetic material S and the hard magnetic material H are magnetically coupled by an exchange coupling action. Therefore, when the distance at which the exchange coupling action works from the interface between the island and the sea (hereinafter referred to as “exchange coupling distance”) is a, in the composite magnetic material 101, the average between two adjacent islands
  • the distance d preferably satisfies d ⁇ 2a. That is, it is preferable that the average distance between two adjacent islands is not more than twice the exchange coupling distance.
  • the average distance d between two adjacent islands is preferably 2 nm or more and 20 nm or less.
  • the average particle size of the particulate island portion including the hard magnetic material H is so large that the coercive force of the hard magnetic material H does not decrease.
  • the hard magnetic material H comprises ⁇ -Fe 2 O 3
  • an average particle size of the particulate island portion comprising hard magnetic material H is the extent to which ⁇ -Fe 2 O 3 it is possible to maintain the epsilon structure Small is preferable.
  • the average particle diameter of the particulate island portion containing the hard magnetic material H is preferably 5 nm or more and 60 nm or less, and more preferably 10 nm or more and 40 nm or less.
  • FIG. 2 is a flowchart showing a method for manufacturing a composite magnetic material according to this embodiment.
  • a first step (S201) for forming a precursor material having a soft magnetic material S and a hard magnetic material H and a second step for oxidizing the precursor material (S201). S202).
  • S201 a first step for forming a precursor material having a soft magnetic material S and a hard magnetic material H
  • a second step for oxidizing the precursor material S201.
  • Step 1 First Step of Forming Precursor Material Having Soft Magnetic Material S and Hard Magnetic Material H
  • This step is a precursor material having a soft magnetic material S containing iron or an iron alloy and a hard magnetic material H. Is a step of forming.
  • This step may be a step of preparing particles of the soft magnetic material S and particles of the hard magnetic material H, and mixing them at an appropriate mixing ratio.
  • the precursor material may be formed by heat-treating (or firing) after mixing and compression molding these.
  • the heat treatment is preferably performed in any of an inert gas atmosphere, a reducing atmosphere, and a vacuum.
  • ⁇ -Fe When ⁇ -Fe is used as the soft magnetic material S, iron oxide or iron hydroxide nanoparticles are generated using a chemical process in solution, and the generated nanoparticles are heat-treated in a reducing atmosphere to form ⁇ -Fe nanoparticles can be synthesized relatively easily. Further, ⁇ -Fe nanoparticles can be directly synthesized without passing through iron oxide or iron hydroxide by adding a reducing agent such as NaBH 4 to a solution containing iron ions to reduce iron ions.
  • a reducing agent such as NaBH 4
  • ⁇ -Fe 2 O 3 When ⁇ -Fe 2 O 3 is used as the hard magnetic material H, iron oxide or iron hydroxide nanoparticles are generated using a chemical process in solution, and the generated nanoparticles are heated in an oxidizing atmosphere. Thus, ⁇ -Fe 2 O 3 particles can be synthesized relatively easily.
  • a reverse micelle method or a sol-gel method using iron nitrate hydrate as a starting material can be used.
  • the surface of the ⁇ -Fe 2 O 3 particles may be added step of coating with silica (SiO 2).
  • a dispersion in which the particles of the other material are dispersed in a solution in which the raw material of one of the soft magnetic material S and the hard magnetic material H is dissolved is prepared.
  • a method of precipitating magnetic material particles or precursor particles thereof may be used. Thereafter, the obtained composite particle powder may be heat-treated.
  • particles of hard magnetic material H are dispersed in a solution in which at least one transition metal element contained in the soft magnetic material S is ionized and dissolved to obtain a dispersion. Thereafter, while stirring the dispersion, an additive such as a pH adjusting agent (typically a basic solution) or a reducing agent is added to the dispersion to precipitate the particles containing the transition metal.
  • the particles to be precipitated may be particles of the intended soft magnetic material S, or may be precursor particles that can be converted into the soft magnetic material S by a subsequent heat treatment or the like. Since the hard magnetic particles are dispersed in the dispersion, the ions are present around the hard magnetic particles in the dispersion so as to surround the hard magnetic particles.
  • the ions react to precipitate particles or precipitates containing the transition metal element in the ions, so that the particles or precipitates are deposited around the hard magnetic particles. Even if the soft magnetic material S and the hard magnetic material H are interchanged, the composite magnetic material can be formed by the same method.
  • ammonia which is a pH adjuster in an aqueous solution containing Fe 3+ ions obtained by dissolving a raw material containing trivalent iron such as iron (III) chloride, iron (III) sulfate, or iron (III) nitrate in water.
  • iron hydroxide Fe (OH) 3
  • the average particle size of the precipitated iron hydroxide particles depends on the deposition conditions, but is generally about 5 nm to 15 nm.
  • This step is a step of oxidizing the precursor material obtained in the first step. Thereby, the soft magnetic material S exposed on the surface of the precursor material is oxidized to generate crystalline iron oxide.
  • a method of heat-treating in an oxidizing atmosphere can be mentioned.
  • the oxidizing atmosphere any one of air, water vapor, oxygen, and a mixed gas of oxygen and an inert gas (argon, nitrogen, helium) can be used.
  • Soft magnetic material S is easily oxidized because it contains iron or an iron alloy. Therefore, when it is taken out into the atmosphere, there is a possibility that oxidation starts to proceed at that time. Therefore, this step is preferably performed continuously from the first step.
  • the temperature range in the heat treatment in the second step is preferably 200 ° C. or higher and 800 ° C. or lower, and more preferably 250 ° C. or higher and 700 ° C. or lower.
  • the composite magnetic material according to the present embodiment can be formed into a desired shape into a nanocomposite magnet.
  • the nanocomposite magnet according to the present embodiment includes a soft magnetic material and a hard magnetic material, the soft magnetic material includes iron or an iron alloy, and the surface of the soft magnetic material is coated with crystalline iron oxide.
  • the nanocomposite magnet according to the present embodiment may be a sintered magnet or a bonded magnet.
  • Sintered magnet A composite magnet material according to the present embodiment is formed into a desired shape, and the obtained molded body is heat-treated in an inert atmosphere or under vacuum to obtain a sintered magnet. Moreover, a sintered magnet can be obtained also by sintering a molded object by plasma activated sintering (PAS: Plasma Activated Sintering) or discharge plasma sintering (SPS: Spark Plasma Sintering). Moreover, an anisotropic sintered magnet is obtained by shaping in a magnetic field.
  • PAS Plasma Activated Sintering
  • SPS Spark Plasma Sintering
  • an anisotropic sintered magnet is obtained by shaping in a magnetic field.
  • a bonded magnet is obtained by blending and molding the composite magnetic material according to the present embodiment and a binder (binder).
  • a binder a resin material such as a thermoplastic resin or a thermosetting resin, a low melting point metal such as Al, Pb, Sn, Zn, or Mg, or an alloy made of these low melting point metals can be used.
  • the composite magnetic material can be formed into a desired shape by compression molding or injection molding the mixture of the composite magnetic material and the binder.
  • An anisotropic bonded magnet can be obtained by molding the composite magnetic material in a magnetic field.
  • the composite magnetic material according to the present embodiment can be suitably used as a material for forming a rotor (rotor) in a motor. That is, the motor according to the present embodiment includes a magnet, and the magnet includes the composite magnetic material according to the present embodiment.
  • FIG. 3 is a diagram schematically showing an example of the structure of the composite magnetic material according to the second embodiment.
  • the composite magnetic material 301 according to the present embodiment includes a core portion including the hard magnetic material H, a shell portion including the soft magnetic material S covering at least a part of the core portion, A core-shell structure.
  • the composite magnetic material 301 includes crystalline iron oxide O that covers at least a part of the surface of the soft magnetic material S. Descriptions similar to those in the first embodiment, such as the hard magnetic material H, the soft magnetic material S, and the crystalline iron oxide O included in the composite magnetic material 301, are omitted as appropriate.
  • the composite magnetic material 301 has a core-shell structure having a core portion including the hard magnetic material H and a shell portion including the soft magnetic material S that covers at least a part of the core portion.
  • the composite magnetic material 301 may be an aggregate of a plurality of core-shell particles.
  • a closed gap that does not communicate with the outside may be formed inside the composite magnetic material 301.
  • the composite magnetic material 301 may have a crystalline oxide O also on the surface of the void.
  • the soft magnetic material S and the hard magnetic material H are magnetically coupled by an exchange coupling action. Therefore, when the distance at which the exchange coupling action works from the interface between the core portion and the shell portion (hereinafter referred to as “exchange coupling distance”) is a, the thickness t of the shell portion satisfies t ⁇ a. preferable. That is, the thickness of the shell part is preferably equal to or less than the exchange coupling distance.
  • the thickness t of the shell portion is preferably 1 nm or more and 20 nm or less, and more preferably 1 nm or more and 10 nm or less.
  • the average particle diameter of the core portion including the hard magnetic material H is large so that the coercive force of the hard magnetic material H does not decrease.
  • the average particle size of the core portion containing the hard magnetic material H is so small that ⁇ -Fe 2 O 3 can maintain the epsilon structure.
  • the average particle size of the core portion including the hard magnetic material H is preferably 5 nm or more and 60 nm or less, and more preferably 10 nm or more and 40 nm or less.
  • the composite magnetic material 301 according to the present embodiment can also be manufactured by the same method as in the first embodiment.
  • the first step (the first step of forming a precursor material having the soft magnetic material S and the hard magnetic material H) is to prepare particles of the hard magnetic material H and process the particles. It may be a step of forming a shell of the soft magnetic material S on the surface of the hard magnetic material H.
  • the synthesized ⁇ -Fe 2 O 3 particles may be heat-treated in a reducing atmosphere after the ⁇ -Fe 2 O 3 particles are synthesized. Thereby, a part of ⁇ -Fe 2 O 3 is reduced from the surface, and ⁇ -Fe which is the soft magnetic material S is formed.
  • Comparative Example 1 In Comparative Example 1, ⁇ -Fe nanoparticles and ⁇ -Fe 2 O 3 particles were respectively prepared, mixed, and heat-treated, so that a composite magnetic material containing ⁇ -Fe and ⁇ -Fe 2 O 3 was used. 1 was produced.
  • ⁇ Fe nanoparticles which are soft magnetic materials, were prepared by the following procedure.
  • iron nitrate hydrate Fe (NO 3) 3 ⁇ 9H 2 O
  • 6g weighed and dissolved in pure water 75 mL, to obtain a nitric acid aqueous solution of iron.
  • an aqueous iron nitrate solution was added to the aqueous ammonia to precipitate iron hydroxide (Fe (OH) 3 ).
  • the precipitated iron hydroxide was collected by filtration, washed thoroughly with pure water, and then vacuum dried to obtain iron hydroxide nanoparticles.
  • the volume-based average particle size was 8 nm.
  • the obtained iron hydroxide nanoparticles were put in an alumina crucible, and the iron hydroxide nanoparticles were heat-treated in a reducing atmosphere to obtain ⁇ -Fe nanoparticles.
  • a mixed gas of 2% hydrogen-98% nitrogen was used as the atmospheric gas during the heat treatment, and the flow rate of the mixed gas was 300 sccm.
  • the temperature during the heat treatment was 500 ° C., held at 500 ° C. for 5 hours, and then cooled to room temperature.
  • the volume-based average particle diameter was 25 nm.
  • ⁇ -Fe 2 O 3 particles which are hard magnetic materials, were prepared by the following procedure.
  • micelle solution (A) and micelle solution (B)) were prepared as follows.
  • TEOS tetraethoxysilane
  • the heat-treated powder was dispersed in a 2 mol / L NaOH aqueous solution and stirred for 24 hours to remove the silica layer on the particle surface. Thereafter, filtration, washing with water and drying were performed to obtain ⁇ -Fe 2 O 3 particles. Further, as a result of analyzing the crystal structure of the obtained ⁇ -Fe 2 O 3 particles by XRD, a diffraction peak of ⁇ -Fe 2 O 3 was confirmed, and a diffraction peak derived from other crystal structures was not confirmed. .
  • the obtained molded body was set in an electric furnace and heat-treated at 260 ° C. for 5 hours in an atmosphere of a mixed gas of hydrogen and nitrogen (2% H 2 -98% N 2 ). After cooling to room temperature, it was coarsely pulverized under a nitrogen gas atmosphere using a planetary ball mill. The powder obtained by coarse pulverization was set again in an electric furnace, and was heat-treated at 260 ° C. for 3 hours in an atmosphere of a mixed gas of hydrogen and nitrogen (2% H 2 -98% N 2 ). Got.
  • Example 1 In Example 1, the composite magnetic material 1 of Comparative Example 1 was used as a precursor material, and the precursor material was oxidized to include ⁇ -Fe and ⁇ -Fe 2 O 3 and have Fe 3 O 4 on the surface. A composite magnetic material 2 was produced.
  • the composite magnetic material 1 obtained in the same manner as in Comparative Example 1 was set in an electric furnace, heat-treated at 350 ° C. for 2 hours while flowing air, and ⁇ -Fe exposed on the particle surface of the particulate composite magnetic material 1 A crystalline iron oxide layer was formed on the surface layer.
  • Comparative Example 2 In Comparative Example 2, ⁇ -Fe 2 O 3 particles were produced in the same manner as in Comparative Example 1, and the produced ⁇ -Fe 2 O 3 particles were subjected to a reduction treatment, whereby ⁇ -Fe and ⁇ -Fe 2 O 3 The composite magnetic material 3 containing these was produced.
  • ⁇ -Fe 2 O 3 particles obtained in the same manner as in Comparative Example 1 were set in an electric furnace and heat-treated at 350 ° C. for 30 minutes in an atmosphere of a mixed gas of hydrogen and nitrogen (2% H 2 -98% N 2). . After cooling to room temperature, it was coarsely pulverized under a nitrogen gas atmosphere using a planetary ball mill. The powder obtained by the coarse pulverization was set again in an electric furnace, and was heat-treated at 350 ° C. for 30 minutes in a mixed gas atmosphere of hydrogen and nitrogen (2% H2-98% N2) to obtain a composite magnetic material 3 .
  • a core-shell structure composed of an ⁇ -Fe 2 O 3 core and an ⁇ -Fe shell was confirmed.
  • amorphous iron oxide was formed with a thickness of about 3 nm.
  • Example 2 the composite magnetic material 3 of Comparative Example 2 is used as a precursor material, and the precursor material is oxidized to include ⁇ -Fe and ⁇ -Fe 2 O 3 and have Fe 3 O 4 on the surface. A composite magnetic material 4 was produced.
  • the composite magnetic material 3 obtained in the same manner as in Comparative Example 2 was set in an electric furnace, heat-treated at 300 ° C. for 10 minutes while flowing air, and ⁇ -Fe exposed on the particle surface of the particulate composite magnetic material 1 A crystalline iron oxide layer was formed on the surface layer.
  • a core-shell structure composed of an ⁇ -Fe 2 O 3 core and an ⁇ -Fe shell was confirmed.
  • a protective layer of crystalline iron oxide having a thickness of about 10 nm was formed on the surface layer of the ⁇ -Fe shell.
  • Comparative Example 3 In Comparative Example 3, the composite magnetic material 1 of Comparative Example 1 was used as a precursor material, and the precursor material was subjected to silica coating treatment, thereby containing ⁇ -Fe and ⁇ -Fe 2 O 3 and having a silica on the surface. Material 5 was produced.
  • Examples 3 to 5 the composite magnetic material 1 of Comparative Example 1 was used as a precursor material in the same manner as in Example 1 except that the oxidation treatment conditions were changed as shown in Table 1, and the precursor material was oxidized. .
  • composite magnetic materials 6 to 8 containing ⁇ -Fe and ⁇ -Fe 2 O 3 and having Fe 3 O 4 on the surface were produced.
  • Example 6 Fe (OH) 3 particles are precipitated in a dispersion liquid in which ⁇ -Fe 2 O 3 particles are dispersed, and this is heat-treated in a reducing atmosphere, so that ⁇ -Fe and ⁇ -Fe 2 O 3 are treated.
  • the precursor material containing was produced. Thereafter, this was oxidized to produce a composite magnetic material containing ⁇ -Fe and ⁇ -Fe 2 O 3 and having Fe 3 O 4 on the surface.
  • Fe (OH) 3 particles were reduced and converted to ⁇ -Fe to prepare a precursor material.
  • 1 g of powder of composite particles of Fe (OH) 3 particles and ⁇ -Fe 2 O 3 particles was processed with a pressure molding machine to produce a molded body.
  • the obtained molded body was set in an electric furnace and heat-treated at 500 ° C. for 5 hours in a mixed gas of hydrogen and nitrogen (2% H 2 -98% N 2 ) (primary firing).
  • the flow rate of the mixed gas was 300 sccm.
  • the powder obtained by coarse pulverization was set again in an electric furnace, and was heat-treated at 260 ° C. for 3 hours in a mixed gas of hydrogen and nitrogen (2% H 2 -98% N 2 ) (secondary firing).
  • a precursor material was obtained.
  • Example 7 Fe 3 O 4 particles were precipitated with a dispersion solution in which ⁇ -Fe 2 O 3 particles were dispersed, and this was heat-treated in a reducing atmosphere, whereby ⁇ -Fe, ⁇ -Fe 2 O 3 and A precursor material containing was prepared. Thereafter, this was oxidized to produce a composite magnetic material containing ⁇ -Fe and ⁇ -Fe 2 O 3 and having Fe 3 O 4 on the surface.
  • the obtained molded body was set in an electric furnace and heat-treated at 470 ° C. for 5 hours in a mixed gas of hydrogen and nitrogen (2% H 2 -98% N 2 ) (primary firing).
  • the flow rate of the mixed gas was 300 sccm.
  • the powder obtained by coarse pulverization was set again in an electric furnace, and was heat-treated at 260 ° C. for 3 hours in a mixed gas of hydrogen and nitrogen (2% H 2 -98% N 2 ) (secondary firing).
  • a precursor material was obtained.
  • Example 8 In Example 8, as in Example 7, Fe 3 O 4 particles were precipitated in a dispersion liquid in which ⁇ -Fe 2 O 3 particles were dispersed, and this was heat-treated in a reducing atmosphere, whereby ⁇ -Fe And a precursor material containing ⁇ -Fe 2 O 3 was prepared. Thereafter, this was oxidized to produce a composite magnetic material containing ⁇ -Fe and ⁇ -Fe 2 O 3 and having Fe 3 O 4 on the surface. In this example, the Fe 3 O 4 particles were precipitated such that the particle size of the precipitated Fe 3 O 4 particles was smaller than that in Example 7.
  • the Fe 3 O 4 particles were reduced and converted to ⁇ -Fe to prepare a precursor material.
  • 0.5 g of composite particles of Fe 3 O 4 particles and ⁇ -Fe 2 O 3 particles were processed with a pressure molding machine to prepare a compact.
  • the obtained molded body was set in an electric furnace and heat-treated at 450 ° C. for 5 hours in a mixed gas of hydrogen and nitrogen (2% H 2 -98% N 2 ) (primary firing).
  • the flow rate of the mixed gas was 300 sccm.
  • the powder obtained by coarse pulverization was set again in an electric furnace, and was heat-treated at 260 ° C. for 3 hours in a mixed gas of hydrogen and nitrogen (2% H 2 -98% N 2 ) (secondary firing).
  • a precursor material was obtained.
  • the obtained precursor material was set in an electric furnace, heat-treated at 350 ° C. for 2 hours while flowing air, and a crystalline iron oxide layer was formed on the surface layer of ⁇ -Fe exposed on the particle surface of the particulate precursor material. Thus, the composite magnetic material 11 was produced.
  • Example 9 a precursor material containing ⁇ -Fe and ⁇ -Fe 2 O 3 was formed by precipitating ⁇ -Fe particles in a dispersion solution in which ⁇ -Fe 2 O 3 particles were dispersed. Thereafter, this was oxidized to produce a composite magnetic material containing ⁇ -Fe and ⁇ -Fe 2 O 3 and having Fe 3 O 4 on the surface.
  • Precursor material production 1 g of composite particles of ⁇ -Fe particles and ⁇ -Fe 2 O 3 particles were processed with a pressure molding machine to produce a compact.
  • the obtained molded body was set in an electric furnace and heat-treated at 400 ° C. for 5 hours in a nitrogen gas atmosphere (primary firing).
  • the flow rate of nitrogen gas was 300 sccm.
  • the powder obtained by coarse pulverization was set again in an electric furnace, and was heat-treated at 260 ° C. for 3 hours in a mixed gas of hydrogen and nitrogen (2% H 2 -98% N 2 ) (secondary firing).
  • a precursor material was obtained.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Powder Metallurgy (AREA)

Abstract

L'invention concerne un matériau magnétique composite qui contient un matériau à aimantation temporaire S et un matériau à aimantation permanente H, et qui est caractérisé en ce que : le matériau à aimantation temporaire S contient du fer ou un alliage de fer ; et au moins une partie de la surface du matériau à aimantation temporaire S est recouverte d'un oxyde de fer cristallin.
PCT/JP2018/014945 2017-04-17 2018-04-09 Matériau magnétique composite, moteur et procédé de production de matériau magnétique composite Ceased WO2018193900A1 (fr)

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JP2017-081522 2017-04-17
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JP2018-023556 2018-02-13
JP2018023556A JP2018182302A (ja) 2017-04-17 2018-02-13 複合磁性材料、モータ、および複合磁性材料の製造方法

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006278470A (ja) * 2005-03-28 2006-10-12 Toyota Motor Corp ナノコンポジット磁石
JP2012209376A (ja) * 2011-03-29 2012-10-25 Tdk Corp 酸化鉄粒子分散液及びナノコンポジット磁石
JP2013102122A (ja) * 2011-10-17 2013-05-23 Sumitomo Electric Ind Ltd 磁性部材及び磁性部材の製造方法
JP2015034343A (ja) * 2013-08-07 2015-02-19 ローベルト ボツシユ ゲゼルシヤフト ミツト ベシユレンクテル ハフツングＲｏｂｅｒｔ Ｂｏｓｃｈ Ｇｍｂｈ 軟磁性金属粉末複合材料およびかかる材料の製造方法
WO2016092744A1 (fr) * 2014-12-12 2016-06-16 ソニー株式会社 Poudre magnétique, procédé de production de celle-ci, et support d'enregistrement magnétique

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006278470A (ja) * 2005-03-28 2006-10-12 Toyota Motor Corp ナノコンポジット磁石
JP2012209376A (ja) * 2011-03-29 2012-10-25 Tdk Corp 酸化鉄粒子分散液及びナノコンポジット磁石
JP2013102122A (ja) * 2011-10-17 2013-05-23 Sumitomo Electric Ind Ltd 磁性部材及び磁性部材の製造方法
JP2015034343A (ja) * 2013-08-07 2015-02-19 ローベルト ボツシユ ゲゼルシヤフト ミツト ベシユレンクテル ハフツングＲｏｂｅｒｔ Ｂｏｓｃｈ Ｇｍｂｈ 軟磁性金属粉末複合材料およびかかる材料の製造方法
WO2016092744A1 (fr) * 2014-12-12 2016-06-16 ソニー株式会社 Poudre magnétique, procédé de production de celle-ci, et support d'enregistrement magnétique

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