WO2024106188A1 - Anisotropic rare earth magnet and method for producing same - Google Patents

Anisotropic rare earth magnet and method for producing same Download PDF

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Publication number
WO2024106188A1
WO2024106188A1 PCT/JP2023/039047 JP2023039047W WO2024106188A1 WO 2024106188 A1 WO2024106188 A1 WO 2024106188A1 JP 2023039047 W JP2023039047 W JP 2023039047W WO 2024106188 A1 WO2024106188 A1 WO 2024106188A1
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magnetic phase
phase
rare earth
atomic
earth magnet
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PCT/JP2023/039047
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French (fr)
Japanese (ja)
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卓也 田村
明軍 李
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国立研究開発法人産業技術総合研究所
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Publication of WO2024106188A1 publication Critical patent/WO2024106188A1/en

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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
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • 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
    • B22F1/05—Metallic powder characterised by the size or surface area of the particles
    • 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
    • B22F1/06—Metallic powder characterised by the shape of the particles
    • 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
    • B22F1/14—Treatment of metallic powder
    • 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
    • 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
    • B22F3/10—Sintering only
    • 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
    • B22F3/12—Both compacting and sintering
    • B22F3/14—Both compacting and sintering simultaneously
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C28/00—Alloys based on a metal not provided for in groups C22C5/00 - C22C27/00
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C30/00—Alloys containing less than 50% by weight of each constituent
    • C22C30/02—Alloys containing less than 50% by weight of each constituent containing copper
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C9/00—Alloys based on copper
    • 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
    • H01F1/047—Alloys characterised by their composition
    • H01F1/053—Alloys characterised by their composition containing rare earth metals
    • H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
    • H01F1/057—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B
    • 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 an anisotropic rare earth magnet and a method for manufacturing the same.
  • rare earth magnets have a high maximum energy product, they are used in energy-saving home appliances such as refrigerators and washing machines, drive motors for fuel-efficient hybrid and electric vehicles, and power steering motors, making them an essential material in modern society.
  • Rare earth magnets are broadly divided into sintered magnets and bonded magnets.
  • patent documents 1-3 propose methods for obtaining sintered magnets.
  • Patent Document 1 describes a method for producing a rare earth magnet, which includes a melting step for preparing a molten alloy of an R-T-B alloy, a first cooling step for cooling the molten alloy to generate crystal nuclei and solidify at least a portion of the molten alloy, and a second cooling step for further cooling the alloy containing the crystal nuclei to obtain alloy flakes.
  • Patent Document 2 describes a method for producing alloy powder for R-Fe-B rare earth magnets, which includes a first crushing step in which a raw alloy for rare earth magnets is coarsely crushed by a hydrogen crushing method, and a second crushing step in which the raw alloy is finely crushed.
  • Patent document 3 describes a method for manufacturing an R-Fe-B rare earth magnet, which includes a pressing step in which rare earth alloy powder is compressed and molded by a dry pressing method to produce a molded body, a step in which an oil agent is impregnated into the molded body from the surface of the molded body, and a step in which the molded body is sintered.
  • Patent Document 4 describes a method for producing anisotropic magnet powder, which includes a mixing step of mixing a hydride (RFeBH x ) powder of an RFeB-based material with a diffusion powder made of a hydride of a simple substance, alloy, or compound of a rare earth element, a diffusion heat treatment step of uniformly diffusing the rare earth element on the surface and inside of the RFeBH x powder after the mixing step, and a dehydrogenation step (second evacuation step) of removing hydrogen from the mixed powder after the diffusion heat treatment step.
  • RFeBH x hydride
  • Non-Patent Document 1 an anisotropic cast rare earth magnet consisting of an R2T14B magnetic phase and an RCu nonmagnetic phase (where R represents a transition metal element including Nd and T represents Fe, for example), in which the R2T14B magnetic phase accounts for 49 volume % (50 weight %), can be produced by an electromagnetic vibration process.
  • Patent Documents 1-4 require a large number of manufacturing steps to obtain a rare earth magnet (sintered magnet or bonded magnet).
  • Non-Patent Document 1 only rare earth magnets with an R2T14B magnetic phase content of 49 volume % or less can be produced, resulting in a saturation magnetization of less than 0.8 T, which is difficult to say has sufficient functionality as a strong magnet.
  • the present invention was made in consideration of the above circumstances, and aims to provide a method for producing an anisotropic rare earth magnet that can produce an anisotropic rare earth magnet with excellent magnetization properties in a small number of steps, and an anisotropic rare earth magnet with a new composition and excellent magnetization properties.
  • An anisotropic rare earth magnet consisting of a plate-shaped magnetic phase and a non-magnetic phase
  • the magnetic phase has a composition represented by R2T14B (where R represents one or more rare earth elements, one or both of which are Nd and/or Pr, and T represents one or more transition metal elements including Fe, or Fe and Co, when the total amount of R is taken as 100 atomic %)
  • the non-magnetic phase has a composition represented by RCu (where R represents one or more rare earth elements, one or both of which are Nd and Pr, and each of which accounts for 50 atomic % or more when the total amount of R is taken as 100 atomic %), and Cu is 6 atomic % or more and 80 atomic % or less;
  • the ratio of the magnetic phase is 51% by volume or more and less than 69% by volume,
  • An anisotropic rare earth magnet having a saturation magnetization of 0.8 T or more.
  • a method for producing an anisotropic rare earth magnet having a saturation magnetization of 0.8 T or more comprising the steps of:
  • the method includes a step of subjecting a mixture of a plate-like magnetic phase and a non-magnetic phase to an orientation treatment under heating, the magnetic phase having a composition represented by R2T14B (where R represents one or more rare earth elements, one or both of which are Nd and/or Pr, and T represents one or more transition metal elements including Fe, or Fe and Co, when the total amount of R is taken as 100 atomic %);
  • the non-magnetic phase has a composition represented by RCu (where R represents one or more rare earth elements, one or both of which are Nd and Pr, and each of which accounts for 50 atomic % or more when the total amount of R is taken as 100 atomic %), and Cu is 6 atomic % or more and 80 atomic % or less;
  • the anisotropic rare earth magnet of the present invention has a new composition and has excellent magnetization properties.
  • the manufacturing method of the anisotropic rare earth magnet of the present invention can produce an anisotropic rare earth magnet with excellent magnetization properties with fewer steps.
  • 1 is an optical micrograph of a mixture of magnetic (R 2 T 14 B) and non-magnetic (RCu) phases produced by casting, the magnetic phase being 54% by volume. 1 shows optical micrographs of anisotropic cast rare earth magnets produced by an electromagnetic vibration process, where (a) the proportion of the magnetic phase ( R2T14B ) in the mixture is 49% by volume, and (b) the proportion of the magnetic phase ( R2T14B ) in the mixture is 54 % by volume.
  • 2A is a cross-sectional photograph of the oriented plate-like magnetic phase as viewed from the side (thickness direction), and FIG.
  • FIG. 2B is a cross-sectional photograph of the oriented plate-like magnetic phase as viewed from above (front), showing the structure of an anisotropic cast rare earth magnet after pressing (orientation treatment).
  • FIG. 1 is a diagram showing a JH curve showing the characteristics of the magnet of the sample of Example 1-3.
  • FIG. 13 is a diagram illustrating an example of pressing (orientation treatment) a round-bar-shaped mixture in a mold in Example 4.
  • FIG. 13 is a diagram showing a JH curve showing the characteristics of the magnet of the sample of Example 4.
  • This article describes one embodiment of the anisotropic rare earth magnet and its manufacturing method of the present invention.
  • the manufacturing method of the present invention is a method for producing an anisotropic rare earth magnet with a saturation magnetization of 0.8 T or more.
  • This manufacturing method includes a step of orienting a mixture of magnetic and non-magnetic phases in a heated state.
  • the magnetic phase has a composition represented by R 2 T 14 B.
  • R represents one or more rare earth elements, with one or both of Nd and Pr being contained at 50 atomic % or more when the total amount is taken as 100 atomic %. More specifically, R may be one or both of Nd and Pr, and may be 50 atomic % or more, 60 atomic % or more, 70 atomic % or more, 80 atomic % or more, 90 atomic % or more, or may be 100 atomic %.
  • the magnetic phase (R 2 T 14 B phase) includes a form having a composition of R 2 Fe 14 B or R 2 (Fe, Co) 14 B, for example.
  • examples of the magnetic phase include Nd-Fe-B based alloys, Pr-Fe-B based alloys, Nd-Pr-Fe-B based alloys, Nd-Ce-Fe-B based alloys, Nd-Pr-Ce-Fe-B based alloys, and Nd-Pr-Ce-Fe-B based alloys, in which part of the Fe is replaced by other transition metals such as Co and Ni.
  • the ratio (volume ratio) of the magnetic phase (R 2 T 14 B phase) in the mixture is 51% by volume or more and less than 69% by volume.
  • the lower limit of the ratio of the magnetic phase (R 2 T 14 B phase) in the mixture is preferably 54% by volume or more, 59% by volume or more, or 64% by volume or more.
  • the upper limit of the ratio of the magnetic phase (R 2 T 14 B phase) in the mixture may be 68% by volume or less.
  • the magnetic phase (R 2 T 14 B phase) has a plate-like shape, and the magnetic phase (R 2 T 14 B phase) preferably has an average thickness of 7 to 12 ⁇ m and an average plate width of 10 to 35 ⁇ m.
  • the magnetic phase (R 2 T 14 B phase) preferably has a melting point of 1000° C. or more and 1300° C. or less, and more preferably has a melting point of 1100° C. or more and 1300° C. or less.
  • the magnetic phase (R 2 T 14 B phase) exhibits such a melting point by having the above composition.
  • the non-magnetic phase has a composition represented by RCu.
  • R represents one or more rare earth elements, with one or both of Nd and Pr being 50 atomic % or more when the total amount is taken as 100 atomic %.
  • R may be one or both of Nd and Pr, and may be 50 atomic % or more, 60 atomic % or more, 70 atomic % or more, 80 atomic % or more, 90 atomic % or more, or may be 100 atomic %.
  • the Cu content in the non-magnetic phase is 6 atomic % or more and 80 atomic % or less, and preferably 20 atomic % or more and 53 atomic % or less.
  • the magnetic phase is oriented by the orientation process, and the saturation magnetization (0.8 T or more) is sufficient for a powerful magnet.
  • the melting point of the non-magnetic phase is preferably 400 to 900°C, and more preferably 400 to 700°C.
  • the non-magnetic phase may contain other elements as long as they do not impair the effects of the present invention.
  • any element that does not exhibit magnetism may be used, and specific examples of such elements include Al, Mg, C, and O.
  • the mixing of the magnetic phase (R 2 T 14 B phase) and the non-magnetic phase (RCu phase) is not particularly limited, and known methods such as casting and powder metallurgy techniques can be adopted.
  • the raw materials of the magnetic phase (R 2 T 14 B phase) and the non-magnetic phase (RCu phase) are all placed in a crucible, and the mixture can be prepared by melting and casting in an inert atmosphere.
  • the magnetic phase (R 2 T 14 B phase) and the non-magnetic phase (RCu phase) can be separately melted and cast, and then crushed, mixed, and pressed into powder to prepare a mixture.
  • the ratio of the magnetic phase in the mixture can be adjusted to 51 volume % or more and less than 69 volume %.
  • the means of orientation treatment is not particularly limited, but examples include hot processing (pressing, rolling, forging, extrusion, etc.).
  • the orientation treatment aligns (anisotropizes) the direction of the easy magnetization axis.
  • the temperature during the orientation treatment (the heating temperature of the mixture of the magnetic phase and the nonmagnetic phase) is equal to or higher than the melting point of the nonmagnetic phase (RCu phase) and equal to or lower than the melting point of the magnetic phase (R 2 T 14 B phase). More preferably, the temperature during the orientation treatment is equal to or higher than the melting point of the nonmagnetic phase (RCu phase) and equal to or lower than the temperature at which the magnetic phase (R 2 T 14 B phase) starts to melt.
  • the magnetic phase (R 2 T 14 B phase) when the orientation treatment is performed, the magnetic phase (R 2 T 14 B phase) is in a solid phase state (including a solid-liquid coexistence state) and the nonmagnetic phase (RCu phase) is in a liquid phase state.
  • the orientation treatment on the mixture of the magnetic phase (R 2 T 14 B phase) and the nonmagnetic phase (RCu phase) in this solid-liquid coexistence state, the magnetic phase (R 2 T 14 B phase) is easily oriented, and the saturation magnetization (0.8 T or more) sufficient for a strong magnet is obtained.
  • the orientation temperature (heating temperature of the mixture of magnetic and non-magnetic phases) depends on the composition of the magnetic phase (R 2 T 14 B phase) and the non-magnetic phase (RCu phase), but for example, the lower limit may be 400° C. or more and the upper limit may be 1100° C. or less, 1000° C. or less, 900° C. or less, or 700° C. or less. Considering the energy during the orientation treatment and the mold life, it is preferable to prepare the composition of the mixture so that it becomes a solid-liquid coexistent state at 400 to 700° C., and to perform the orientation treatment at this temperature.
  • the pressure applied to the mixture may be, for example, 50 MPa or more, 100 MPa or more, 200 MPa or more, or 500 MPa or more.
  • the magnetic phase (R 2 T 14 B phase) is preferably plate-shaped, with an average thickness of 7 to 12 ⁇ m and an average plate width of 10 to 35 ⁇ m.
  • the magnetic phase has a sufficient saturation magnetization (0.8 T or more) as a strong magnet.
  • the method for measuring the average thickness and average plate width of the magnetic phase (R 2 T 14 B phase) may be a known method, but for example, they can be calculated based on the average domain width and average domain length of the magnetic phase (R 2 T 14 B phase) according to the measurement method described in the examples below.
  • the average plate width of the magnetic phase (R 2 T 14 B phase) does not necessarily have to be 10 to 35 ⁇ m before the orientation treatment, and the magnetic phase (R 2 T 14 B phase) is easily crushed during the orientation treatment such as hot working, and the average plate width can be adjusted to 10 to 35 ⁇ m.
  • the average thickness of the magnetic phase (R 2 T 14 B phase) is desirably 7 to 12 ⁇ m before the orientation treatment.
  • the ratio of the average plate width to the average thickness of the magnetic phase ( R2T14B phase ) is preferably 1.5 to 15.
  • the saturation magnetization 0.8 T or more is sufficient for a strong magnet.
  • the magnetic phase (R 2 T 14 B phase) and the non-magnetic phase (RCu phase) have a predetermined composition, and the ratio of the magnetic phase (R 2 T 14 B phase) is 51 volume % or more and less than 69 volume %.
  • the magnetic phase (R 2 T 14 B phase) is oriented by simply performing an orientation treatment such as hot treatment on a mixture of the magnetic phase (R 2 T 14 B phase) and the non-magnetic phase (RCu phase) at a temperature equal to or higher than the melting point of the non-magnetic phase (RCu phase) and equal to or lower than the melting point of the magnetic phase (R 2 T 14 B phase), so that an anisotropic rare earth magnet with excellent magnetization characteristics can be easily obtained.
  • this manufacturing method does not require the complicated steps required in the conventional method, and an anisotropic rare earth magnet with excellent magnetization characteristics (saturation magnetization of 0.8 T or more) can be obtained by the orientation treatment step under the above conditions.
  • anisotropic rare earth magnet (anisotropic rare earth magnet)
  • the anisotropic rare earth magnet of the present invention can be obtained by the manufacturing method of the anisotropic rare earth magnet of the present invention described above. Some of the explanations of the anisotropic rare earth magnet of the present invention that overlap with the explanations of the manufacturing method described above will be omitted.
  • the anisotropic rare earth magnet of the present invention consists of a magnetic phase and a non-magnetic phase, with the magnetic phase oriented in one direction.
  • the magnetic phase has a composition represented by R 2 T 14 B.
  • R is at least either Nd or Pr, and is one or more rare earth elements that are 50 atomic % or more of either or both of Nd and Pr. More specifically, R may be either or both of Nd and Pr that are 50 atomic % or more, 60 atomic % or more, 70 atomic % or more, 80 atomic % or more, 90 atomic % or more, or may be 100 atomic %.
  • T is one or more transition metal elements including Fe or Fe and Co. That is, the magnetic phase includes a form having a composition of R 2 Fe 14 B or R 2 (Fe, Co) 14 B.
  • the proportion (volume fraction) of the magnetic phase ( R2T14B phase) in the anisotropic rare earth magnet is 51 volume% or more and less than 69 volume%.
  • the lower limit of the proportion of the magnetic phase ( R2T14B phase ) is, in order of preference, 51 volume% or more, 54 volume% or more, 59 volume% or more, and 64 volume% or more.
  • the upper limit of the proportion of the magnetic phase ( R2T14B phase ) is, for example, 68 volume% or less.
  • the proportion (volume fraction) of the magnetic phase ( R2T14B phase) of an anisotropic rare earth magnet can be determined, for example, by the average area fraction (area % ) of the magnetic phase in multiple observation planes from at least three or more fields of view in which a cross section parallel to the pressure direction of the orientation treatment (hot working such as pressing) can be observed.
  • the magnet When the proportion of the magnetic phase (R 2 T 14 B phase) in the anisotropic rare earth magnet is within this range, the magnet has sufficient saturation magnetization (0.8 T or more) to function as a strong magnet.
  • the magnetic phase (R 2 T 14 B phase) is plate-shaped.
  • the magnetic phase in the anisotropic rare earth magnet preferably has an average thickness of 7 to 12 ⁇ m and an average plate width of 10 to 35 ⁇ m. If the average thickness and average plate width of the magnetic phase (R 2 T 14 B phase) are within these ranges, the anisotropic rare earth magnet will have sufficient saturation magnetization (0.8 T or more) to function as a strong magnet.
  • the ratio of the average plate width to the average thickness of the magnetic phase ( R2T14B phase ) (average plate width/average thickness) is preferably from 1.5 to 15.
  • the anisotropic rare earth magnet has sufficient saturation magnetization (0.8 T or more) to function as a strong magnet.
  • the magnetic phase (R 2 T 14 B phase) preferably has a melting point of 1000°C or higher and 1300°C or lower, and more preferably 1100°C or higher and 1300°C or lower.
  • the magnetic phase may contain elements other than R, T and B as long as the effects of the present invention are not impaired.
  • the non-magnetic phase has a composition represented by RCu.
  • R represents one or more rare earth elements, with one or both of Nd and Pr being 50 atomic % or more when the total amount is 100 atomic %.
  • R may be one or both of Nd and Pr, and may be 50 atomic % or more, 60 atomic % or more, 70 atomic % or more, 80 atomic % or more, 90 atomic % or more, or may be 100 atomic %.
  • the Cu content in the non-magnetic phase is 6 atomic % or more and 80 atomic % or less, and preferably 20 atomic % or more and 53 atomic % or less. When the Cu content in the non-magnetic phase is in this range, it has sufficient saturation magnetization (0.8 T or more) to function as a strong magnet.
  • the melting point of the non-magnetic phase is preferably 400 to 900°C, and more preferably 400 to 700°C.
  • the non-magnetic phase may contain other elements as long as they do not impair the effects of the present invention.
  • any element that does not exhibit magnetism may be used, and specific examples of such elements include Al, Mg, C, and O.
  • the anisotropic rare earth magnet of the present invention is composed of a magnetic phase ( R2T14B phase ) having the above-mentioned composition and a non-magnetic phase (RCu phase), and has excellent magnetic properties.
  • the anisotropic rare earth magnet of the present invention has a saturation magnetization of 0.8 T or more, preferably 0.9 T or more, and more preferably 1.0 T or more.
  • the anisotropic rare earth magnet and its manufacturing method of the present invention are not limited to the above embodiments.
  • the manufacturing method of the anisotropic rare earth magnet of the present invention may include known steps other than those described above.
  • the anisotropic rare earth magnet of the present invention may contain unavoidable impurities that arise during the manufacturing process.
  • anisotropic rare earth magnet of the present invention and its manufacturing method will be described below with examples, but the anisotropic rare earth magnet of the present invention and its manufacturing method are not limited to the following examples.
  • Nd2Fe14B was selected as the magnetic phase
  • Nd-30 atomic % Cu alloy was selected as the non-magnetic phase.
  • the master alloys constituting the magnetic and non-magnetic phases were weighed out so that the ratios of the magnetic phase were 49 volume % and 54 volume %, respectively, and melted by high-frequency melting in an inert atmosphere (molten metal temperature 1600°C), and cast into a carbon steel mold thickly coated with a BN mold release agent to produce a ⁇ 6 mm round bar-shaped mixture.
  • Magnetic phase ( Nd2Fe14B ): 54 volume %, non-magnetic phase (Nd-30 atomic % Cu alloy)) is shown in Figure 1.
  • the white phase is the magnetic phase (Nd2Fe14B ) and the other phases are the non-magnetic phase (Nd-30 atomic % Cu alloy).
  • This rod-shaped mixture was cut into 15 mm pieces, then set in a superconducting magnet.
  • the magnetic field was raised to 10 T under Ar flow and the sample temperature was heated to 700°C.
  • an alternating current of 250 Hz and 90 A was applied for 120 s.
  • an alternating current of 1000 Hz and 90 A was applied for 120 s, followed by air cooling to 400°C (approximately 200 s) and lowering the magnetic field to 0 T. This was a two-step electromagnetic vibration process.
  • Nd 2 Fe 14 B was selected as the magnetic phase (R 2 T 14 B), and Nd-30 atomic % Cu alloy was selected as the non-magnetic phase (RCu).
  • the mother alloy was weighed so that the ratio of the magnetic phase (Nd 2 Fe 14 B) and the non-magnetic phase (Nd-30 atomic %) was a predetermined ratio (Example 1: magnetic phase 54 volume %, Example 2: magnetic phase 59 volume %, Example 3: magnetic phase 64 volume %, Comparative Example 1: magnetic phase 69 volume %), melted by high-frequency melting in an inert atmosphere (molten metal temperature 1600 ° C.), and cast into a carbon steel mold thickly coated with a BN mold release agent to produce a ⁇ 6 mm mixture round bar. By this casting, a round bar-shaped mixture consisting of the magnetic phase (Nd 2 Fe 14 B) and the non-magnetic phase (Nd-30 atomic % Cu) was prepared.
  • the rod-shaped mixture was cut into a length of 5 mm, heated to 700° C. in air, and pressed into a plate by placing a weight of 11 kg on it (orientation treatment). Note that the sample of Comparative Example 1, which contains 69 volume % of the magnetic phase (Nd 2 Fe 14 B), could not be pressed.
  • Figure 3 shows optical microscope photographs of the samples of Examples 1-3 after pressing.
  • Figure 3(a) is a cross-sectional photograph of the oriented plate-like magnetic phase viewed from the side (thickness direction (a))
  • Figure 3(b) is a cross-sectional photograph of the oriented plate-like magnetic phase viewed from above (front (press) direction (b)).
  • Table 1 shows the average thickness, average plate width, and average plate width/average thickness of the magnetic phase (Nd 2 Fe 14 B) measured at various locations of the samples of Examples 1-3.
  • the measurement method of the average thickness and the average plate width is as follows. First, the sample is cut and polished so that the cross section parallel to the pressing direction can be observed. The mirror-finished observation surface is photographed with an optical microscope at any location so that one pixel of the image is 0.564 x 0.564 ⁇ m, and the image is 1280 x 960 pixels. At this time, the photograph is taken so that the pressing direction is the vertical axis of the image. The photographed image is measured with Image-Pro Premier Ver9.3. First, in the "Morphological" tab, a filter is applied with "Shrinkage, shape 2 x 2 square, number of times 4". Then, binarization is performed so that only the magnetic phase is selected, and the average region length and average region width are measured.
  • the ratio ( volume fraction) of the magnetic phase (R2T14B phase ) in the samples after pressing was calculated from the average area fraction (area %) of the magnetic phase in a plurality of observation planes of at least three fields of view in which a cross section parallel to the pressing direction could be observed.
  • the ratio (volume fraction) of the magnetic phase ( R2T14B phase ) in the samples after pressing was 54 volume % for the sample of Example 1, 59 volume % for the sample of the Example, and 64 volume % for the sample of Example 3.
  • the average thickness was 7 to 12 ⁇ m and the average plate width was within the range of 10 to 35 ⁇ m.
  • the ratio of the average plate width to the average thickness was 1.5 or more.
  • Example 1 magnetic phase 54% by volume
  • Example 2 magnetic phase 59% by volume
  • Example 3 magnetic phase 64% by volume
  • Nd 2 Fe 14 B was selected as the magnetic phase (R 2 T 14 B), and Nd-30 atomic % Cu alloy was selected as the non-magnetic phase (RCu).
  • the master alloy was weighed so that the ratio of the magnetic phase (Nd 2 Fe 14 B) and the non-magnetic phase (Nd-30 atomic %) was 64 volume % of the magnetic phase. Then, this was melted by high-frequency melting in an inert atmosphere (molten metal temperature 1600 ° C.) and cast into a carbon steel mold thickly coated with a BN mold release agent to produce a round bar-shaped mixture of ⁇ 6 mm. By this casting, a round bar-shaped mixture consisting of the magnetic phase (Nd 2 Fe 14 B) and the non-magnetic phase (Nd-30 atomic % Cu) was prepared.
  • This rod-shaped mixture was cut to a length of 5 mm, then heated to 620°C in air and pressed into a plate of 1 mm thickness with a load of 450 MPa using a mold as shown in Figure 5 (orientation treatment).
  • the part used as the magnet was the bottom part with a diameter of 6 mm.
  • the ratio ( volume fraction) of the magnetic phase ( R2T14B phase) in the sample after pressing was calculated from the average area fraction (area %) of the magnetic phase in three observation fields where a cross section parallel to the pressing direction could be observed.
  • the ratio (volume fraction) of the magnetic phase ( R2T14B phase) in the sample after pressing was 67.6 volume %.
  • the average thickness, average plate width, and average plate width/average thickness of the magnetic phase (Nd 2 Fe 14 B) measured at various locations on the sample of Example 4 are shown in Table 2.
  • the average thickness and average plate width are measured as follows. First, the sample is cut and polished so that a cross section parallel to the pressing direction can be observed. A scanning electron microscope photograph is taken of an arbitrary location of the mirror-finished observation surface so that one pixel of the image is 0.1 x 0.1 ⁇ m in the backscattered electron image of the scanning electron microscope, resulting in a 1280 x 960 pixel image. At this time, the photograph is taken so that the pressing direction is the vertical axis of the image. The captured image is measured using Image-Pro Premier Ver9.3. First, a filter is applied in the "Morphological" tab with "Expansion, shape 2 x 2 square, number of times 4".
  • binarization is performed so that only the magnetic phase is selected, and the average region length and average region width are measured. However, objects with a region width value of 2 pixels (0.2 ⁇ m) or less are excluded.
  • the values obtained by adding 0.8 ⁇ m, the reduction due to the expansion filter, to these values is taken as the average plate width, i.e., (average region length + 0.8 ⁇ m) is the average plate width, and (average region width + 0.8 ⁇ m) is the average thickness.
  • the average ratio of the average plate width to the average thickness was calculated using the average plate width and average thickness of one captured image; 20 images were processed, and the range of these values is shown in Table 2.
  • the average thickness was 7 to 12 ⁇ m and the average plate width was within 10 to 35 ⁇ m.
  • the ratio of the average plate width to the average thickness was 1.5 or more.
  • Example 6 shows the JH curve indicating the magnetic properties of the sample of Example 4. It was confirmed that Example 4 (magnetic phase 67.6% by volume) had high remanent magnetization, exhibited coercive force, and was an anisotropic magnet with a saturation magnetization of 0.8 T or more.

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Abstract

An anisotropic rare earth magnet comprising a magnetic phase and a non-magnetic phase, wherein: the magnetic phase has a composition represented by R2T14B (if the total amount is 100 at.%, R represents one or more rare earth elements which include Nd and/or Pr in an amount greater than or equal to 50 at.%, and T represents one or more transition metal elements which include Fe, or Fe and Co); the non-magnetic phase has a composition represented by RCu (if the total amount is 100 at.%, R represents one or more rare earth elements which include Nd and/or Pr in an amount greater than or equal to 50 at.%); Cu constitutes 6-80 at.%, inclusive; the proportion which the magnetic phase constitutes is at least 51 vol.% and less than 69 vol.%; and the saturation magnetization is at least 0.8T.

Description

異方性希土類磁石およびその製造方法Anisotropic rare earth magnet and its manufacturing method
　本発明は、異方性希土類磁石およびその製造方法に関する。 The present invention relates to an anisotropic rare earth magnet and a method for manufacturing the same.
　希土類磁石は、高い最大エネルギー積を有していることから、冷蔵庫・洗濯機等の省エネ家電や高燃費自動車であるハイブリッド自動車・電気自動車等の駆動用モーター、パワーステアリング用モーター等に使用されており、現代社会に必要不可欠な材料となっている。 Because rare earth magnets have a high maximum energy product, they are used in energy-saving home appliances such as refrigerators and washing machines, drive motors for fuel-efficient hybrid and electric vehicles, and power steering motors, making them an essential material in modern society.
　希土類磁石は、焼結磁石とボンド磁石に大別される。 Rare earth magnets are broadly divided into sintered magnets and bonded magnets.
　焼結磁石を得る方法として、例えば、特許文献１－３の方法が提案されている。 For example, patent documents 1-3 propose methods for obtaining sintered magnets.
　特許文献１には、Ｒ－Ｔ－Ｂ系合金の合金溶湯を調製する溶融工程と、合金溶湯を冷却して結晶核を生成させ、合金溶湯の少なくとも一部を凝固させる第１の冷却工程と、結晶核を含む合金をさらに冷却して合金薄片を得る第２の冷却工程と、を有する希土類磁石の製造方法が記載されている。 Patent Document 1 describes a method for producing a rare earth magnet, which includes a melting step for preparing a molten alloy of an R-T-B alloy, a first cooling step for cooling the molten alloy to generate crystal nuclei and solidify at least a portion of the molten alloy, and a second cooling step for further cooling the alloy containing the crystal nuclei to obtain alloy flakes.
　特許文献２には、希土類磁石用原料合金を水素粉砕法により粗粉砕を行う第１粉砕工程と、前記原料合金の微粉砕を行う第２粉砕工程とを含むＲ－Ｆｅ－Ｂ系希土類磁石用合金粉末の製造方法が記載されている。 Patent Document 2 describes a method for producing alloy powder for R-Fe-B rare earth magnets, which includes a first crushing step in which a raw alloy for rare earth magnets is coarsely crushed by a hydrogen crushing method, and a second crushing step in which the raw alloy is finely crushed.
　特許文献３には、希土類合金粉末を乾式プレス法によって圧縮成形することによって成形体を作製するプレス工程と、前記成形体の表面から油剤を前記成形体に含浸させる工程と、前記成形体を焼結させる工程と、を包含するＲ－Ｆｅ－Ｂ系希土類磁石の製造方法が記載されている。 Patent document 3 describes a method for manufacturing an R-Fe-B rare earth magnet, which includes a pressing step in which rare earth alloy powder is compressed and molded by a dry pressing method to produce a molded body, a step in which an oil agent is impregnated into the molded body from the surface of the molded body, and a step in which the molded body is sintered.
　ボンド磁石を得る方法として、例えば、特許文献４の方法が提案されている。特許文献４には、ＲＦｅＢ系材料の水素化物（ＲＦｅＢＨＸ）粉末と、希土類元素の単体、合金、化合物の水素化物からなる拡散粉末とを混合する混合工程と、混合工程後に希土類元素をＲＦｅＢＨＸ粉末の表面および内部に均一に拡散させる拡散熱処理工程と、該拡散熱処理工程後の混合粉末から水素を除去する脱水素工程（第２排気工程）と、からなる異方性磁石粉末の製造方法が記載されている。 As a method for obtaining a bonded magnet, for example, the method of Patent Document 4 has been proposed. Patent Document 4 describes a method for producing anisotropic magnet powder, which includes a mixing step of mixing a hydride (RFeBH x ) powder of an RFeB-based material with a diffusion powder made of a hydride of a simple substance, alloy, or compound of a rare earth element, a diffusion heat treatment step of uniformly diffusing the rare earth element on the surface and inside of the RFeBH x powder after the mixing step, and a dehydrogenation step (second evacuation step) of removing hydrogen from the mixed powder after the diffusion heat treatment step.
　さらに、本発明者は、非特許文献１において、Ｒ２Ｔ１４Ｂ磁性相とＲＣｕ非磁性相からなり（例えば、ＲはＮｄ、ＴはＦｅを含む遷移金属元素を示す）、Ｒ２Ｔ１４Ｂ磁性相が４９体積％（５０重量％）である異方性鋳造希土類磁石が電磁振動プロセスにて作製可能であることを報告している。 Furthermore, the present inventors have reported in Non-Patent Document 1 that an anisotropic cast rare earth magnet consisting of an R2T14B magnetic phase and an RCu nonmagnetic phase (where R represents a transition metal element including Nd and T represents Fe, for example), in which the R2T14B magnetic phase accounts for 49 volume % (50 weight %), can be produced by an electromagnetic vibration process.
ＷＯ２０１３－５４８４５WO2013-54845 特開２００２－３３２０６号公報JP 2002-33206 A 特開２００２－１７０７２８号公報JP 2002-170728 A 特開２００２－９３６１０号公報JP 2002-93610 A
　しかしながら、特許文献１－４の製造方法の場合、上述したように、希土類磁石（焼結磁石またはボンド磁石）を得るために非常に多数の製造工程を経る必要がある。 However, as mentioned above, the manufacturing methods described in Patent Documents 1-4 require a large number of manufacturing steps to obtain a rare earth magnet (sintered magnet or bonded magnet).
　一方、非特許文献１の製造方法の場合、Ｒ２Ｔ１４Ｂ磁性相の含有量が４９体積％以下の希土類磁石しか作製することができないため、飽和磁化が０．８Ｔ未満となり、強力磁石として十分な機能を有しているとは言い難かった。 On the other hand, in the case of the manufacturing method described in Non-Patent Document 1, only rare earth magnets with an R2T14B magnetic phase content of 49 volume % or less can be produced, resulting in a saturation magnetization of less than 0.8 T, which is difficult to say has sufficient functionality as a strong magnet.
　本発明は、以上のような事情に鑑みてなされたものであり、少ない工程で、磁化特性に優れた異方性希土類磁石を得ることができる異方性希土類磁石の製造方法と、新しい組成を有し、磁化特性に優れた異方性希土類磁石を提供することを課題としている。 The present invention was made in consideration of the above circumstances, and aims to provide a method for producing an anisotropic rare earth magnet that can produce an anisotropic rare earth magnet with excellent magnetization properties in a small number of steps, and an anisotropic rare earth magnet with a new composition and excellent magnetization properties.
　上記の課題を解決するため、以下の異方性希土類磁石が提供される。
［１］板状の磁性相と、非磁性相とからなる異方性希土類磁石であって、
　前記磁性相は、Ｒ２Ｔ１４Ｂで表される組成を有し（ただし、Ｒは、その総量を１００原子％としたときに、ＮｄまたはＰｒのうちの一方または両方が５０原子％以上含まれる１種または２種以上の希土類元素を示し、Ｔは、Ｆｅ、または、ＦｅおよびＣｏを含む１種または２種以上の遷移金属元素を示す）、
　前記非磁性相は、ＲＣｕで表される組成を有し（ただし、Ｒは、その総量を１００原子％としたときに、ＮｄまたはＰｒのうちの一方または両方が５０原子％以上含まれる１種または２種以上の希土類元素を示す）、かつ、Ｃｕが６原子％以上８０原子％以下 であり、
　前記磁性相の割合が５１体積％以上６９体積％未満であり、
　飽和磁化が０．８Ｔ以上である
ことを特徴とする異方性希土類磁石。
［２］前記磁性相は、平均厚みが７～１２μｍであり、かつ、平均板幅が１０～３５μｍである
ことを特徴とする前記［１］の異方性希土類磁石。
［３］前記磁性相の平均板幅と平均厚みの比（平均板幅／平均厚み）が１．５以上１５以下である
ことを特徴とする前記［１］または［２］の異方性希土類磁石。
［４］前記磁性相の融点が１０００℃以上１３００℃以下であり、前記非磁性相の融点が４００℃～９００℃である
ことを特徴とする前記［１］から［３］の異方性希土類磁石。 In order to solve the above problems, the following anisotropic rare earth magnet is provided.
[1] An anisotropic rare earth magnet consisting of a plate-shaped magnetic phase and a non-magnetic phase,
The magnetic phase has a composition represented by R2T14B (where R represents one or more rare earth elements, one or both of which are Nd and/or Pr, and T represents one or more transition metal elements including Fe, or Fe and Co, when the total amount of R is taken as 100 atomic %);
The non-magnetic phase has a composition represented by RCu (where R represents one or more rare earth elements, one or both of which are Nd and Pr, and each of which accounts for 50 atomic % or more when the total amount of R is taken as 100 atomic %), and Cu is 6 atomic % or more and 80 atomic % or less;
The ratio of the magnetic phase is 51% by volume or more and less than 69% by volume,
An anisotropic rare earth magnet having a saturation magnetization of 0.8 T or more.
[2] The anisotropic rare earth magnet according to [1], wherein the magnetic phase has an average thickness of 7 to 12 μm and an average plate width of 10 to 35 μm.
[3] The anisotropic rare earth magnet according to [1] or [2], characterized in that the ratio of the average plate width to the average thickness of the magnetic phase (average plate width/average thickness) is 1.5 or more and 15 or less.
[4] The anisotropic rare earth magnet according to any one of [1] to [3], characterized in that the melting point of the magnetic phase is 1000°C or higher and 1300°C or lower, and the melting point of the non-magnetic phase is 400°C to 900°C.
　上記の課題を解決するため、以下の異方性希土類磁石の製造方法が提供される。
［５］飽和磁化が０．８Ｔ以上である異方性希土類磁石の製造方法であって、
　板状の磁性相と、非磁性相とからなる混合物を加熱状態で配向処理する工程を含み、　前記磁性相は、Ｒ２Ｔ１４Ｂで表される組成を有し（ただし、Ｒは、その総量を１００原子％としたときに、ＮｄまたはＰｒのうちの一方または両方が５０原子％以上含まれる１種または２種以上の希土類元素を示し、Ｔは、Ｆｅ、または、ＦｅおよびＣｏを含む１種または２種以上の遷移金属元素を示す）、
　前記非磁性相は、ＲＣｕで表される組成を有し（ただし、Ｒは、その総量を１００原子％としたときに、ＮｄまたはＰｒのうちの一方または両方が５０原子％以上含まれる１種または２種以上の希土類元素を示す）、かつ、Ｃｕが６原子％以上８０原子％以下であり、
　前記磁性相の割合が５１体積％以上６９体積％未満であり、
　前記混合物の加熱温度は、前記非磁性相の融点以上、かつ、前記磁性相の融点以下である
　ことを特徴とする異方性希土類磁石の製造方法。
［６］前記配向処理後において、前記磁性相は、平均厚みが７～１２μｍであり、かつ、平均板幅が１０～３５μｍである
ことを特徴とする前記［５］の異方性希土類磁石の製造方法。
［７］前記配向処理後において、前記磁性相は、平均板幅と平均厚みの比（平均板幅／平均厚み）が１．５以上１５以下である
ことを特徴とする前記［５］または［６］の異方性希土類磁石の製造方法。
［８］前記磁性相の融点が１０００℃以上１３００℃以下であり、前記非磁性相の融点が４００℃～９００℃である
ことを特徴とする前記［５］から［７］の異方性希土類磁石の製造方法。 In order to solve the above problems, the following method for producing an anisotropic rare earth magnet is provided.
[5] A method for producing an anisotropic rare earth magnet having a saturation magnetization of 0.8 T or more, comprising the steps of:
The method includes a step of subjecting a mixture of a plate-like magnetic phase and a non-magnetic phase to an orientation treatment under heating, the magnetic phase having a composition represented by R2T14B (where R represents one or more rare earth elements, one or both of which are Nd and/or Pr, and T represents one or more transition metal elements including Fe, or Fe and Co, when the total amount of R is taken as 100 atomic %);
The non-magnetic phase has a composition represented by RCu (where R represents one or more rare earth elements, one or both of which are Nd and Pr, and each of which accounts for 50 atomic % or more when the total amount of R is taken as 100 atomic %), and Cu is 6 atomic % or more and 80 atomic % or less;
The ratio of the magnetic phase is 51 volume % or more and less than 69 volume %,
a heating temperature of the mixture is equal to or higher than the melting point of the nonmagnetic phase and equal to or lower than the melting point of the magnetic phase.
[6] The method for producing an anisotropic rare earth magnet according to [5], wherein after the orientation treatment, the magnetic phase has an average thickness of 7 to 12 μm and an average plate width of 10 to 35 μm.
[7] The method for producing an anisotropic rare earth magnet according to [5] or [6], characterized in that after the orientation treatment, the ratio of the average plate width to the average thickness (average plate width/average thickness) of the magnetic phase is 1.5 or more and 15 or less.
[8] The method for producing an anisotropic rare earth magnet according to any one of [5] to [7], characterized in that the melting point of the magnetic phase is 1000°C or higher and 1300°C or lower, and the melting point of the non-magnetic phase is 400°C to 900°C.
　本発明の異方性希土類磁石は、新しい組成を有し、磁化特性に優れている。本発明の異方性希土類磁石の製造方法は、少ない工程で、磁化特性に優れた異方性希土類磁石を得ることができる。 The anisotropic rare earth magnet of the present invention has a new composition and has excellent magnetization properties. The manufacturing method of the anisotropic rare earth magnet of the present invention can produce an anisotropic rare earth magnet with excellent magnetization properties with fewer steps.
鋳造によって作製した磁性相（Ｒ２Ｔ１４Ｂ）および非磁性相（ＲＣｕ）の混合物の光学顕微鏡写真である。混合物中の磁性相は、５４体積％である。1 is an optical micrograph of a mixture of magnetic (R 2 T 14 B) and non-magnetic (RCu) phases produced by casting, the magnetic phase being 54% by volume. 電磁振動プロセスにて作製した異方性鋳造希土類磁石の光学顕微鏡写真である。（ａ）は、混合物中の磁性相（Ｒ２Ｔ１４Ｂ）の割合が４９体積％であり、（ｂ）は、混合物中の磁性相（Ｒ２Ｔ１４Ｂ）の割合が５４体積％である。1 shows optical micrographs of anisotropic cast rare earth magnets produced by an electromagnetic vibration process, where (a) the proportion of the magnetic phase ( R2T14B ) in the mixture is 49% by volume, and (b) the proportion of the magnetic phase ( R2T14B ) in the mixture is 54 % by volume. プレス（配向処理）後の異方性鋳造希土類磁石の組織を示した光学顕微鏡写真である。（ａ）は、配向した板状の磁性相を横（厚み方向）から見た断面写真であり、図２（ｂ）は、配向した板状の磁性相を上（正面）から見た断面写真である。2A is a cross-sectional photograph of the oriented plate-like magnetic phase as viewed from the side (thickness direction), and FIG. 2B is a cross-sectional photograph of the oriented plate-like magnetic phase as viewed from above (front), showing the structure of an anisotropic cast rare earth magnet after pressing (orientation treatment). 実施例１－３の試料の磁石の特性を示すＪＨ曲線を示す図である。FIG. 1 is a diagram showing a JH curve showing the characteristics of the magnet of the sample of Example 1-3. 実施例４において、丸棒状の混合物を金型にてプレス（配向処理）する形態を例示した図である。FIG. 13 is a diagram illustrating an example of pressing (orientation treatment) a round-bar-shaped mixture in a mold in Example 4. 実施例４の試料の磁石の特性を示すＪＨ曲線を示す図である。FIG. 13 is a diagram showing a JH curve showing the characteristics of the magnet of the sample of Example 4.
　本発明の異方性希土類磁石およびその製造方法の一実施形態について説明する。 This article describes one embodiment of the anisotropic rare earth magnet and its manufacturing method of the present invention.
（異方性希土類磁石の製造方法）
　本発明の製造方法は、飽和磁化が０．８Ｔ以上である異方性希土類磁石を製造する方法である。 (Method of manufacturing anisotropic rare earth magnets)
The manufacturing method of the present invention is a method for producing an anisotropic rare earth magnet with a saturation magnetization of 0.8 T or more.
　この製造方法は、磁性相と非磁性相とからなる混合物を加熱状態で配向処理する工程を含む。 This manufacturing method includes a step of orienting a mixture of magnetic and non-magnetic phases in a heated state.
　磁性相は、Ｒ２Ｔ１４Ｂで表される組成を有している。 The magnetic phase has a composition represented by R 2 T 14 B.
　ここで、Ｒは、その総量を１００原子％としたときに、ＮｄまたはＰｒのうちの一方または両方が５０原子％以上含まれる１種または２種以上の希土類元素を示している。より具体的には、Ｒは、ＮｄまたはＰｒのうちの一方または両方で、５０原子％以上、６０原子％以上、７０原子％以上、８０原子％以上、９０原子％以上であってよく、１００原子％であってもよい。 Here, R represents one or more rare earth elements, with one or both of Nd and Pr being contained at 50 atomic % or more when the total amount is taken as 100 atomic %. More specifically, R may be one or both of Nd and Pr, and may be 50 atomic % or more, 60 atomic % or more, 70 atomic % or more, 80 atomic % or more, 90 atomic % or more, or may be 100 atomic %.
　Ｔは、Ｆｅ、または、ＦｅおよびＣｏを含む１種または２種以上の遷移金属元素である。すなわち、磁性相（Ｒ２Ｔ１４Ｂ相）は、例えば、Ｒ２Ｆｅ１４ＢまたはＲ２（Ｆｅ、Ｃｏ）１４Ｂの組成を有する形態が含まれる。 T is Fe, or one or more transition metal elements including Fe and Co. That is, the magnetic phase (R 2 T 14 B phase) includes a form having a composition of R 2 Fe 14 B or R 2 (Fe, Co) 14 B, for example.
　より具体的には、磁性相（Ｒ２Ｔ１４Ｂ相）の例としては、Ｎｄ－Ｆｅ－Ｂ系合金、Ｐｒ－Ｆｅ－Ｂ系合金、Ｎｄ－Ｐｒ－Ｆｅ－Ｂ系合金、Ｎｄ－Ｃｅ－Ｆｅ－Ｂ系合金、Ｎｄ－Ｐｒ－Ｃｅ－Ｆｅ－Ｂ系合金、これらにおけるＦｅの一部をＣｏ、Ｎｉ等の他の遷移金属で置換したもの等が挙げられる。 More specifically, examples of the magnetic phase (R 2 T 14 B phase) include Nd-Fe-B based alloys, Pr-Fe-B based alloys, Nd-Pr-Fe-B based alloys, Nd-Ce-Fe-B based alloys, Nd-Pr-Ce-Fe-B based alloys, and Nd-Pr-Ce-Fe-B based alloys, in which part of the Fe is replaced by other transition metals such as Co and Ni.
　混合物中の磁性相（Ｒ２Ｔ１４Ｂ相）の割合（体積率）は、５１体積％以上６９体積％未満である。また、優れた飽和磁化を実現する観点からは、混合物中の磁性相（Ｒ２Ｔ１４Ｂ相）の割合の下限値は、５４体積％以上、５９体積％以上、６４体積％以上であることが好ましい。混合物中の磁性相（Ｒ２Ｔ１４Ｂ相）の割合の上限値は、６８体積％以下であってよい。混合物中の磁性相（Ｒ２Ｔ１４Ｂ相）の割合がこの範囲であると、後述する配向処理によって、磁性相（Ｒ２Ｔ１４Ｂ相）が配向し、強力磁石として十分な飽和磁化（０．８Ｔ以上）になる。 The ratio (volume ratio) of the magnetic phase (R 2 T 14 B phase) in the mixture is 51% by volume or more and less than 69% by volume. In addition, from the viewpoint of realizing excellent saturation magnetization, the lower limit of the ratio of the magnetic phase (R 2 T 14 B phase) in the mixture is preferably 54% by volume or more, 59% by volume or more, or 64% by volume or more. The upper limit of the ratio of the magnetic phase (R 2 T 14 B phase) in the mixture may be 68% by volume or less. When the ratio of the magnetic phase (R 2 T 14 B phase) in the mixture is within this range, the magnetic phase (R 2 T 14 B phase) is oriented by the orientation treatment described later, and the saturation magnetization (0.8 T or more) sufficient for a strong magnet is obtained.
　また、磁性相（Ｒ２Ｔ１４Ｂ相）の形状は、板状である。磁性相（Ｒ２Ｔ１４Ｂ相）は、平均厚みが７～１２μｍであり、かつ、平均板幅が１０～３５μｍであることが好ましい。 The magnetic phase (R 2 T 14 B phase) has a plate-like shape, and the magnetic phase (R 2 T 14 B phase) preferably has an average thickness of 7 to 12 μm and an average plate width of 10 to 35 μm.
　磁性相（Ｒ２Ｔ１４Ｂ相）は、融点が１０００℃以上１３００℃以下であることが好ましく、１１００℃以上１３００℃以下であることがより好ましい。磁性相（Ｒ２Ｔ１４Ｂ相）は、上記の組成を有していることで、このような融点を示す。 The magnetic phase (R 2 T 14 B phase) preferably has a melting point of 1000° C. or more and 1300° C. or less, and more preferably has a melting point of 1100° C. or more and 1300° C. or less. The magnetic phase (R 2 T 14 B phase) exhibits such a melting point by having the above composition.
　非磁性相は、ＲＣｕで表される組成を有している。磁性相と同様に、Ｒは、その総量を１００原子％としたときに、ＮｄまたはＰｒのうちの一方または両方が５０原子％以上含まれる１種または２種以上の希土類元素を示している。Ｒは、ＮｄまたはＰｒのうちの一方または両方で、５０原子％以上、６０原子％以上、７０原子％以上、８０原子％以上、９０原子％以上であってよく、１００原子％であってもよい。 The non-magnetic phase has a composition represented by RCu. As with the magnetic phase, R represents one or more rare earth elements, with one or both of Nd and Pr being 50 atomic % or more when the total amount is taken as 100 atomic %. R may be one or both of Nd and Pr, and may be 50 atomic % or more, 60 atomic % or more, 70 atomic % or more, 80 atomic % or more, 90 atomic % or more, or may be 100 atomic %.
　非磁性相（ＲＣｕ相）中のＣｕは、６原子％以上８０原子％以下であり、２０原子％以上５３原子％であることが好ましい。非磁性相中のＣｕがこの範囲であると、配向処理によって磁性相が配向し、強力磁石として十分な飽和磁化（０．８Ｔ以上）になる。 The Cu content in the non-magnetic phase (RCu phase) is 6 atomic % or more and 80 atomic % or less, and preferably 20 atomic % or more and 53 atomic % or less. When the Cu content in the non-magnetic phase is within this range, the magnetic phase is oriented by the orientation process, and the saturation magnetization (0.8 T or more) is sufficient for a powerful magnet.
　非磁性相（ＲＣｕ相）は、融点が４００～９００℃であることが好ましく、４００～７００℃であることがより好ましい。 The melting point of the non-magnetic phase (RCu phase) is preferably 400 to 900°C, and more preferably 400 to 700°C.
　なお、非磁性相（ＲＣｕ相）は、本発明の効果を損なわない範囲で、他の元素が含有されていてもよい。すなわち、磁性を示さないもの（非磁性）であればよく、具体的には、例えば、Ａｌ、Ｍｇ、Ｃ、Ｏなどの元素を例示することができる。 The non-magnetic phase (RCu phase) may contain other elements as long as they do not impair the effects of the present invention. In other words, any element that does not exhibit magnetism (non-magnetic) may be used, and specific examples of such elements include Al, Mg, C, and O.
　磁性相（Ｒ２Ｔ１４Ｂ相）と非磁性相（ＲＣｕ相）との混合は、特に限定されず、鋳造や粉末冶金技術などの公知の方法を採用することができる。例えば、鋳造の場合は、磁性相（Ｒ２Ｔ１４Ｂ相）と非磁性相（ＲＣｕ相）の原料を全てルツボ内に入れ、不活性雰囲気中にて溶解・鋳造することにより混合物を作製することができる。別の方法としては、例えば、磁性相（Ｒ２Ｔ１４Ｂ相）と非磁性相（ＲＣｕ相）を別々に溶解・鋳造し、その後、粉砕・混合・圧粉するなどして混合物を作製することができる。この際、上述したように、混合物における磁性相の割合を、５１体積％以上６９体積％未満に調整することができる。 The mixing of the magnetic phase (R 2 T 14 B phase) and the non-magnetic phase (RCu phase) is not particularly limited, and known methods such as casting and powder metallurgy techniques can be adopted. For example, in the case of casting, the raw materials of the magnetic phase (R 2 T 14 B phase) and the non-magnetic phase (RCu phase) are all placed in a crucible, and the mixture can be prepared by melting and casting in an inert atmosphere. As another method, for example, the magnetic phase (R 2 T 14 B phase) and the non-magnetic phase (RCu phase) can be separately melted and cast, and then crushed, mixed, and pressed into powder to prepare a mixture. In this case, as described above, the ratio of the magnetic phase in the mixture can be adjusted to 51 volume % or more and less than 69 volume %.
　配向処理の手段は、特に限定されないが、熱間加工（プレス、圧延、鍛造、押出加工など）を例示することができる。配向処理によって、磁化容易軸方向が配向（異方化）する。 The means of orientation treatment is not particularly limited, but examples include hot processing (pressing, rolling, forging, extrusion, etc.). The orientation treatment aligns (anisotropizes) the direction of the easy magnetization axis.
　そして、本発明の製造方法では、配向処理の際の温度（磁性相と非磁性相との混合物の加熱温度）は、非磁性相（ＲＣｕ相）の融点以上、かつ、磁性相（Ｒ２Ｔ１４Ｂ相）の融点以下である。さらに、好ましくは、配向処理の際の温度は、非磁性相（ＲＣｕ相）の融点以上、かつ、磁性相（Ｒ２Ｔ１４Ｂ相）の溶解が始まる温度以下である。すなわち、この製造方法においては、配向処理を行う際、磁性相（Ｒ２Ｔ１４Ｂ相）が固相状態（固液共存状態を含む）であり、かつ、非磁性相（ＲＣｕ相）が液相状態である。磁性相（Ｒ２Ｔ１４Ｂ相）と非磁性相（ＲＣｕ相）との混合物について、この固液共存状態で配向処理を行うことで、容易に磁性相（Ｒ２Ｔ１４Ｂ相）が配向し、強力磁石として十分な飽和磁化（０．８Ｔ以上）になる。 In the manufacturing method of the present invention, the temperature during the orientation treatment (the heating temperature of the mixture of the magnetic phase and the nonmagnetic phase) is equal to or higher than the melting point of the nonmagnetic phase (RCu phase) and equal to or lower than the melting point of the magnetic phase (R 2 T 14 B phase). More preferably, the temperature during the orientation treatment is equal to or higher than the melting point of the nonmagnetic phase (RCu phase) and equal to or lower than the temperature at which the magnetic phase (R 2 T 14 B phase) starts to melt. That is, in this manufacturing method, when the orientation treatment is performed, the magnetic phase (R 2 T 14 B phase) is in a solid phase state (including a solid-liquid coexistence state) and the nonmagnetic phase (RCu phase) is in a liquid phase state. By performing the orientation treatment on the mixture of the magnetic phase (R 2 T 14 B phase) and the nonmagnetic phase (RCu phase) in this solid-liquid coexistence state, the magnetic phase (R 2 T 14 B phase) is easily oriented, and the saturation magnetization (0.8 T or more) sufficient for a strong magnet is obtained.
　具体的には、配向処理の温度（磁性相と非磁性相との混合物の加熱温度）は、磁性相（Ｒ２Ｔ１４Ｂ相）と非磁性相（ＲＣｕ相）の組成によるが、例えば、下限値は、４００℃以上であり、上限値は、１１００℃以下、１０００℃以下、９００℃以下、７００℃以下であってよい。配向処理時のエネルギーや型寿命を考慮すると、４００～７００℃で固液共存状態となるように混合物の組成を調製し、この温度で配向処理することが好ましい。 Specifically, the orientation temperature (heating temperature of the mixture of magnetic and non-magnetic phases) depends on the composition of the magnetic phase (R 2 T 14 B phase) and the non-magnetic phase (RCu phase), but for example, the lower limit may be 400° C. or more and the upper limit may be 1100° C. or less, 1000° C. or less, 900° C. or less, or 700° C. or less. Considering the energy during the orientation treatment and the mold life, it is preferable to prepare the composition of the mixture so that it becomes a solid-liquid coexistent state at 400 to 700° C., and to perform the orientation treatment at this temperature.
　また、配向処理が熱間加工である場合、混合物に対して加える圧力は、例えば、５０ＭＰａ以上、１００ＭＰａ以上、２００ＭＰａ以上、５００ＭＰａ以上であってよい。 In addition, when the orientation treatment is hot working, the pressure applied to the mixture may be, for example, 50 MPa or more, 100 MPa or more, 200 MPa or more, or 500 MPa or more.
　また、配向処理後において、磁性相（Ｒ２Ｔ１４Ｂ相）は、板状であり、平均厚みが７～１２μｍであり、かつ、平均板幅が１０～３５μｍであることが好ましい。磁性相（Ｒ２Ｔ１４Ｂ相）の平均厚みおよび平均板幅がこの範囲であると、強力磁石として十分な飽和磁化（０．８Ｔ以上）になる。磁性相（Ｒ２Ｔ１４Ｂ相）の平均厚みおよび平均板幅の測定方法については、公知の方法であってよいが、例えば、後述する実施例に記載の測定方法に従い、磁性相（Ｒ２Ｔ１４Ｂ相）の平均領域幅および平均領域長さに基づいて算出することができる。 Moreover, after the orientation treatment, the magnetic phase (R 2 T 14 B phase) is preferably plate-shaped, with an average thickness of 7 to 12 μm and an average plate width of 10 to 35 μm. When the average thickness and average plate width of the magnetic phase (R 2 T 14 B phase) are within this range, the magnetic phase has a sufficient saturation magnetization (0.8 T or more) as a strong magnet. The method for measuring the average thickness and average plate width of the magnetic phase (R 2 T 14 B phase) may be a known method, but for example, they can be calculated based on the average domain width and average domain length of the magnetic phase (R 2 T 14 B phase) according to the measurement method described in the examples below.
　なお、磁性相（Ｒ２Ｔ１４Ｂ相）の平均板幅は、配向処理前の状態においては、必ずしも１０～３５μｍである必要はなく、熱間加工などの配向処理時に磁性相（Ｒ２Ｔ１４Ｂ相）は容易に破砕され、平均板幅を１０～３５μｍに調整することができる。一方、磁性相（Ｒ２Ｔ１４Ｂ相）の平均厚みは、配向処理前の状態において平均厚み７～１２μｍであることが望ましい。 The average plate width of the magnetic phase (R 2 T 14 B phase) does not necessarily have to be 10 to 35 μm before the orientation treatment, and the magnetic phase (R 2 T 14 B phase) is easily crushed during the orientation treatment such as hot working, and the average plate width can be adjusted to 10 to 35 μm. On the other hand, the average thickness of the magnetic phase (R 2 T 14 B phase) is desirably 7 to 12 μm before the orientation treatment.
　さらに、磁性相（Ｒ２Ｔ１４Ｂ相）の平均板幅と平均厚みの比（平均板幅／平均厚み）は、１．５以上１５以下であることが好ましい。磁性相（Ｒ２Ｔ１４Ｂ相）の平均板幅と平均厚みの比（平均板幅/平均厚み）がこの範囲であると、強力磁石として十分な飽和磁化（０．８Ｔ以上）になる。 Furthermore, the ratio of the average plate width to the average thickness of the magnetic phase ( R2T14B phase ) (average plate width/average thickness) is preferably 1.5 to 15. When the ratio of the average plate width to the average thickness of the magnetic phase ( R2T14B phase) (average plate width/average thickness) is within this range, the saturation magnetization ( 0.8 T or more) is sufficient for a strong magnet.
　以上のように、この製造方法では、磁性相（Ｒ２Ｔ１４Ｂ相）と非磁性相（ＲＣｕ相）が所定の組成を有し、磁性相（Ｒ２Ｔ１４Ｂ相）の割合が５１体積％以上６９体積％未満である。そして、磁性相（Ｒ２Ｔ１４Ｂ相）と非磁性相（ＲＣｕ相）との混合物を、非磁性相（ＲＣｕ相）の融点以上、かつ、磁性相（Ｒ２Ｔ１４Ｂ相）の融点以下で熱間処理などの配向処理をするのみで、磁性相（Ｒ２Ｔ１４Ｂ相）が配向するため、磁化特性に優れた異方性希土類磁石を容易に得ることができる。すなわち、この製造方法では、従来の方法で必要とされていた複雑な工程が不要であり、上記の条件による配向処理の工程により、優れた磁化特性を有する（飽和磁化が０．８Ｔ以上である）異方性希土類磁石を得ることができる。 As described above, in this manufacturing method, the magnetic phase (R 2 T 14 B phase) and the non-magnetic phase (RCu phase) have a predetermined composition, and the ratio of the magnetic phase (R 2 T 14 B phase) is 51 volume % or more and less than 69 volume %. Then, the magnetic phase (R 2 T 14 B phase) is oriented by simply performing an orientation treatment such as hot treatment on a mixture of the magnetic phase (R 2 T 14 B phase) and the non-magnetic phase (RCu phase) at a temperature equal to or higher than the melting point of the non-magnetic phase (RCu phase) and equal to or lower than the melting point of the magnetic phase (R 2 T 14 B phase), so that an anisotropic rare earth magnet with excellent magnetization characteristics can be easily obtained. In other words, this manufacturing method does not require the complicated steps required in the conventional method, and an anisotropic rare earth magnet with excellent magnetization characteristics (saturation magnetization of 0.8 T or more) can be obtained by the orientation treatment step under the above conditions.
（異方性希土類磁石）
　本発明の異方性希土類磁石は、上述した本発明の異方性希土類磁石の製造方法によって得ることができる。本発明の異方性希土類磁石について、上記の製造方法において説明した内容と重複する内容については、説明を一部省略する。 (anisotropic rare earth magnet)
The anisotropic rare earth magnet of the present invention can be obtained by the manufacturing method of the anisotropic rare earth magnet of the present invention described above. Some of the explanations of the anisotropic rare earth magnet of the present invention that overlap with the explanations of the manufacturing method described above will be omitted.
　本発明の異方性希土類磁石は、磁性相と非磁性相とからなり、磁性相が一方向に配向している。 The anisotropic rare earth magnet of the present invention consists of a magnetic phase and a non-magnetic phase, with the magnetic phase oriented in one direction.
　磁性相は、Ｒ２Ｔ１４Ｂで表される組成を有している。 The magnetic phase has a composition represented by R 2 T 14 B.
　ここで、Ｒは、ＮｄまたはＰｒのうちの少なくともいずれかであり、Ｎｄ、Ｐｒのうちの一方または両方で、５０原子％以上となる１種または２種以上の希土類元素である。より具体的には、Ｒは、ＮｄまたはＰｒのうちの一方または両方で、５０原子％以上、６０原子％以上、７０原子％以上、８０原子％以上、９０原子％以上であってよく、１００原子％であってもよい。 Here, R is at least either Nd or Pr, and is one or more rare earth elements that are 50 atomic % or more of either or both of Nd and Pr. More specifically, R may be either or both of Nd and Pr that are 50 atomic % or more, 60 atomic % or more, 70 atomic % or more, 80 atomic % or more, 90 atomic % or more, or may be 100 atomic %.
　Ｔは、Ｆｅ、または、ＦｅおよびＣｏを含む１種または２種以上の遷移金属元素である。すなわち、磁性相は、Ｒ２Ｆｅ１４ＢまたはＲ２（Ｆｅ、Ｃｏ）１４Ｂの組成を有する形態が含まれる。 T is one or more transition metal elements including Fe or Fe and Co. That is, the magnetic phase includes a form having a composition of R 2 Fe 14 B or R 2 (Fe, Co) 14 B.
　異方性希土類磁石における磁性相（Ｒ２Ｔ１４Ｂ相）の割合（体積率）は、５１体積％以上６９体積％未満である。磁性相（Ｒ２Ｔ１４Ｂ相）の割合の下限値は、好ましい順に、５１体積％以上、５４体積％以上、５９体積％以上、６４体積％以上が例示される。磁性相（Ｒ２Ｔ１４Ｂ相）の割合の上限値は、６８体積％以下が例示される。異方性希土類磁石における磁性相の割合がこの範囲であると、強力磁石として十分な飽和磁化（０．８Ｔ以上）になる。
　なお、異方性希土類磁石の磁性相（Ｒ２Ｔ１４Ｂ相）の割合（体積率）は、例えば、配向処理（プレスなどの熱間加工）の加圧方向と平行となる断面が観察できるような最低３視野以上の複数の観察面における磁性相の平均面積率（面積％）を体積率（体積％）とすることができる。 The proportion (volume fraction) of the magnetic phase ( R2T14B phase) in the anisotropic rare earth magnet is 51 volume% or more and less than 69 volume%. The lower limit of the proportion of the magnetic phase ( R2T14B phase ) is, in order of preference, 51 volume% or more, 54 volume% or more, 59 volume% or more, and 64 volume% or more. The upper limit of the proportion of the magnetic phase ( R2T14B phase ) is, for example, 68 volume% or less. When the proportion of the magnetic phase in the anisotropic rare earth magnet is in this range, the magnet has sufficient saturation magnetization (0.8 T or more) to function as a strong magnet.
The proportion (volume fraction) of the magnetic phase ( R2T14B phase) of an anisotropic rare earth magnet can be determined, for example, by the average area fraction (area % ) of the magnetic phase in multiple observation planes from at least three or more fields of view in which a cross section parallel to the pressure direction of the orientation treatment (hot working such as pressing) can be observed.
　異方性希土類磁石における磁性相（Ｒ２Ｔ１４Ｂ相）の割合がこの範囲であることで、強力磁石として十分な飽和磁化（０．８Ｔ以上）になる。 When the proportion of the magnetic phase (R 2 T 14 B phase) in the anisotropic rare earth magnet is within this range, the magnet has sufficient saturation magnetization (0.8 T or more) to function as a strong magnet.
　また、磁性相（Ｒ２Ｔ１４Ｂ相）は、板状である。具体的には、異方性希土類磁石中の磁性相は、平均厚みが７～１２μｍであり、かつ、平均板幅が１０～３５μｍであることが好ましい。磁性相（Ｒ２Ｔ１４Ｂ相）の平均厚みおよび平均板幅がこの範囲であると、異方性希土類磁石は、強力磁石として十分な飽和磁化（０．８Ｔ以上）になる。 Furthermore, the magnetic phase (R 2 T 14 B phase) is plate-shaped. Specifically, the magnetic phase in the anisotropic rare earth magnet preferably has an average thickness of 7 to 12 μm and an average plate width of 10 to 35 μm. If the average thickness and average plate width of the magnetic phase (R 2 T 14 B phase) are within these ranges, the anisotropic rare earth magnet will have sufficient saturation magnetization (0.8 T or more) to function as a strong magnet.
　さらに、磁性相（Ｒ２Ｔ１４Ｂ相）の平均板幅と平均厚みの比（平均板幅／平均厚み）は、１．５以上１５以下であることが好ましい。磁性相（Ｒ２Ｔ１４Ｂ相）の平均板幅と平均厚みの比（平均板幅/平均厚み）がこの範囲であると、異方性希土類磁石は、強力磁石として十分な飽和磁化（０．８Ｔ以上）になる。 Furthermore, the ratio of the average plate width to the average thickness of the magnetic phase ( R2T14B phase ) (average plate width/average thickness) is preferably from 1.5 to 15. When the ratio of the average plate width to the average thickness of the magnetic phase ( R2T14B phase) (average plate width/average thickness) is within this range, the anisotropic rare earth magnet has sufficient saturation magnetization (0.8 T or more) to function as a strong magnet.
　磁性相（Ｒ２Ｔ１４Ｂ相）は、融点が１０００℃以上１３００℃以下であることが好ましく、１１００℃以上１３００℃以下であることがより好ましい。 The magnetic phase (R 2 T 14 B phase) preferably has a melting point of 1000°C or higher and 1300°C or lower, and more preferably 1100°C or higher and 1300°C or lower.
　さらに、磁性相は、本発明の効果を損なわない範囲において、Ｒ、ＴおよびＢ以外の元素を含み得る。 Furthermore, the magnetic phase may contain elements other than R, T and B as long as the effects of the present invention are not impaired.
　非磁性相は、ＲＣｕで表される組成を有している。磁性相（Ｒ２Ｔ１４Ｂ相）と同様に、Ｒは、その総量を１００原子％としたときに、ＮｄまたはＰｒのうちの一方または両方が５０原子％以上含まれる１種または２種以上の希土類元素を示している。Ｒは、ＮｄまたはＰｒのうちの一方または両方で、５０原子％以上、６０原子％以上、７０原子％以上、８０原子％以上、９０原子％以上であってよく、１００原子％であってもよい。 The non-magnetic phase has a composition represented by RCu. As with the magnetic phase ( R2T14B phase), R represents one or more rare earth elements, with one or both of Nd and Pr being 50 atomic % or more when the total amount is 100 atomic %. R may be one or both of Nd and Pr, and may be 50 atomic % or more, 60 atomic % or more, 70 atomic % or more, 80 atomic % or more, 90 atomic % or more, or may be 100 atomic %.
　非磁性相（ＲＣｕ相）中のＣｕは、６原子％以上８０原子％以下であり、２０原子％以上５３原子％であることが好ましい。非磁性相中のＣｕの含有量がこの範囲であると、強力磁石として十分な飽和磁化（０．８Ｔ以上）になる。 The Cu content in the non-magnetic phase (RCu phase) is 6 atomic % or more and 80 atomic % or less, and preferably 20 atomic % or more and 53 atomic % or less. When the Cu content in the non-magnetic phase is in this range, it has sufficient saturation magnetization (0.8 T or more) to function as a strong magnet.
　非磁性相（ＲＣｕ相）は、融点が４００～９００℃であることが好ましく、４００～７００℃であることがより好ましい。 The melting point of the non-magnetic phase (RCu phase) is preferably 400 to 900°C, and more preferably 400 to 700°C.
　なお、非磁性相（ＲＣｕ相）は、本発明の効果を損なわない範囲で、他の元素が含有されていてもよい。すなわち、磁性を示さないもの（非磁性）であればよく、具体的には、例えば、Ａｌ、Ｍｇ、Ｃ、Ｏなど元素を例示することができる。 The non-magnetic phase (RCu phase) may contain other elements as long as they do not impair the effects of the present invention. In other words, any element that does not exhibit magnetism (non-magnetic) may be used, and specific examples of such elements include Al, Mg, C, and O.
　本発明の異方性希土類磁石は、上述した組成を有する磁性相（Ｒ２Ｔ１４Ｂ相）と非磁性相（ＲＣｕ相）とからなり、優れた磁気特性を有している。具体的には、本発明の異方性希土類磁石は、飽和磁化が０．８Ｔ以上であり、好ましくは０．９Ｔ以上であり、より好ましくは、１．０Ｔ以上である。 The anisotropic rare earth magnet of the present invention is composed of a magnetic phase ( R2T14B phase ) having the above-mentioned composition and a non-magnetic phase (RCu phase), and has excellent magnetic properties. Specifically, the anisotropic rare earth magnet of the present invention has a saturation magnetization of 0.8 T or more, preferably 0.9 T or more, and more preferably 1.0 T or more.
　本発明の異方性希土類磁石およびその製造方法は、以上の実施形態に限定されるものではない。例えば、本発明の異方性希土類磁石の製造方法は、上述した以外の公知の工程を含むこともできる。また、例えば、本発明の異方性希土類磁石には、製造過程で生じる不可避不純物を含んでいてもよい。 The anisotropic rare earth magnet and its manufacturing method of the present invention are not limited to the above embodiments. For example, the manufacturing method of the anisotropic rare earth magnet of the present invention may include known steps other than those described above. Also, for example, the anisotropic rare earth magnet of the present invention may contain unavoidable impurities that arise during the manufacturing process.
　以下、本発明の異方性希土類磁石およびその製造方法について、実施例とともに説明するが、本発明の異方性希土類磁石およびその製造方法は、以下の実施例に何ら限定されるものではない。 The anisotropic rare earth magnet of the present invention and its manufacturing method will be described below with examples, but the anisotropic rare earth magnet of the present invention and its manufacturing method are not limited to the following examples.
　＜参考例＞
　非特許文献１の記載に従って、電磁振動プロセスによって異方性希土類磁石を作製した。 <Reference Example>
Anisotropic rare earth magnets were fabricated by an electromagnetic vibration process according to the description in Non-Patent Document 1.
　具体的には、磁性相としてＮｄ２Ｆｅ１４Ｂ、非磁性相としてＮｄ-３０原子％Ｃｕ合金を選択した。磁性相の割合が４９体積％、５４体積％となるように、磁性相および非磁性相を構成する母合金を秤量し、不活性雰囲気中高周波溶解（溶湯温度１６００℃）にて溶解、ＢＮ離型剤を厚く塗布した炭素鋼鋳型に鋳込むことによりφ６ｍｍ丸棒状の混合物を作製した。 Specifically, Nd2Fe14B was selected as the magnetic phase, and Nd-30 atomic % Cu alloy was selected as the non-magnetic phase. The master alloys constituting the magnetic and non-magnetic phases were weighed out so that the ratios of the magnetic phase were 49 volume % and 54 volume %, respectively, and melted by high-frequency melting in an inert atmosphere (molten metal temperature 1600°C), and cast into a carbon steel mold thickly coated with a BN mold release agent to produce a φ6 mm round bar-shaped mixture.
　この混合物（磁性相（Ｎｄ２Ｆｅ１４Ｂ）：５４体積％、非磁性相（Ｎｄ-３０原子％Ｃｕ合金））の光学顕微鏡写真を図１に示す。白い相が磁性相（Ｎｄ２Ｆｅ１４Ｂ）、その他の相が非磁性相（Ｎｄ-３０原子％Ｃｕ合金）である。 An optical microscope photograph of this mixture (magnetic phase ( Nd2Fe14B ): 54 volume %, non-magnetic phase (Nd-30 atomic % Cu alloy)) is shown in Figure 1. The white phase is the magnetic phase (Nd2Fe14B ) and the other phases are the non-magnetic phase (Nd-30 atomic % Cu alloy).
　この丸棒状の混合物を１５ｍｍに切断後、超電導マグネットにセットし、Ａｒフロー下にて磁場を１０Ｔまで上昇・試料温度を７００℃まで加熱、１段階目：２５０Ｈｚ、９０Ａの交流電流を１２０ｓ印加、２段階目：１０００Ｈｚ、９０Ａの交流電流を１２０ｓ印加、４００℃まで空冷（約２００ｓ）、磁場を０Ｔまで降下、という２段階の電磁振動プロセスにて行った。 This rod-shaped mixture was cut into 15 mm pieces, then set in a superconducting magnet. The magnetic field was raised to 10 T under Ar flow and the sample temperature was heated to 700°C. In the first step, an alternating current of 250 Hz and 90 A was applied for 120 s. In the second step, an alternating current of 1000 Hz and 90 A was applied for 120 s, followed by air cooling to 400°C (approximately 200 s) and lowering the magnetic field to 0 T. This was a two-step electromagnetic vibration process.
　その結果、混合物中の磁性相（Ｎｄ２Ｆｅ１４Ｂ）の割合が４９体積％である場合、図２(a)のように完全に配向化が行うことができたが、飽和磁化が０．８Ｔ未満（０．７９Ｔ）であり、強力磁石として十分な機能を有していないことが確認された。一方、混合物中の磁性相（Ｎｄ2Ｆｅ14Ｂ）の割合が５４体積％の場合、図２（ｂ）のように大半は粉砕できず、磁石として機能しないことが確認された。 As a result, when the ratio of the magnetic phase (Nd 2 Fe 14 B) in the mixture was 49% by volume, complete orientation was achieved as shown in Figure 2(a), but the saturation magnetization was less than 0.8 T (0.79 T), and it was confirmed that it did not have sufficient functionality as a strong magnet. On the other hand, when the ratio of the magnetic phase (Nd 2 Fe 14 B) in the mixture was 54% by volume, most of it could not be crushed as shown in Figure 2(b), and it was confirmed that it did not function as a magnet.
　＜実施例１－３、比較例１＞
　磁性相（Ｒ２Ｔ１４Ｂ）としてＮｄ２Ｆｅ１４Ｂ、非磁性相（ＲＣｕ）としてＮｄ－３０原子％Ｃｕ合金を選択した。磁性相（Ｎｄ２Ｆｅ１４Ｂ）および非磁性相（Ｎｄ－３０原子％）の割合が所定の割合（実施例１：磁性相５４体積％、実施例２：磁性相５９体積％、実施例３：磁性相６４体積％、比較例１：磁性相６９体積％）となるように母合金を秤量し、不活性雰囲気中高周波溶解（溶湯温度１６００℃）にて溶解、BN離型剤を厚く塗布した炭素鋼鋳型に鋳込むことによりφ６ｍｍ混合体丸棒を作製した。この鋳造により、磁性相（Ｎｄ２Ｆｅ１４Ｂ）および非磁性相（Ｎｄ－３０原子％Ｃｕ）からなる丸棒状の混合物を準備した。 <Examples 1 to 3, Comparative Example 1>
Nd 2 Fe 14 B was selected as the magnetic phase (R 2 T 14 B), and Nd-30 atomic % Cu alloy was selected as the non-magnetic phase (RCu). The mother alloy was weighed so that the ratio of the magnetic phase (Nd 2 Fe 14 B) and the non-magnetic phase (Nd-30 atomic %) was a predetermined ratio (Example 1: magnetic phase 54 volume %, Example 2: magnetic phase 59 volume %, Example 3: magnetic phase 64 volume %, Comparative Example 1: magnetic phase 69 volume %), melted by high-frequency melting in an inert atmosphere (molten metal temperature 1600 ° C.), and cast into a carbon steel mold thickly coated with a BN mold release agent to produce a φ6 mm mixture round bar. By this casting, a round bar-shaped mixture consisting of the magnetic phase (Nd 2 Fe 14 B) and the non-magnetic phase (Nd-30 atomic % Cu) was prepared.
　この丸棒状の混合物を長さ５ｍｍに切断後、大気中で７００℃まで加熱、１１ｋｇの重りをのせることにより丸棒を板状にプレスした（配向処理）。なお、ただし、磁性相（Ｎｄ2Ｆｅ14Ｂ）が６９体積％である比較例１の試料はプレスすることができなかった。 The rod-shaped mixture was cut into a length of 5 mm, heated to 700° C. in air, and pressed into a plate by placing a weight of 11 kg on it (orientation treatment). Note that the sample of Comparative Example 1, which contains 69 volume % of the magnetic phase (Nd 2 Fe 14 B), could not be pressed.
　実施例１－３の試料について、プレス後の試料の光学顕微鏡写真を図３に示す。図３（ａ）は配向した板状の磁性相を横（厚み方向（ａ））から見た断面写真、図３（ｂ）は、配向した板状磁性相を上（正面（プレス）方向（ｂ））から見た断面写真である。 Figure 3 shows optical microscope photographs of the samples of Examples 1-3 after pressing. Figure 3(a) is a cross-sectional photograph of the oriented plate-like magnetic phase viewed from the side (thickness direction (a)), and Figure 3(b) is a cross-sectional photograph of the oriented plate-like magnetic phase viewed from above (front (press) direction (b)).
　実施例１－３の試料の様々な場所で測定した磁性相（Ｎｄ２Ｆｅ１４Ｂ）の平均厚み、平均板幅、平均板幅/平均厚みの値を表１に示す。 Table 1 shows the average thickness, average plate width, and average plate width/average thickness of the magnetic phase (Nd 2 Fe 14 B) measured at various locations of the samples of Examples 1-3.
　なお、平均厚みおよび平均板幅の測定方法は以下の通りである。まず、プレス方向と平行になる断面が観察できるように試料を切断、研磨を行う。鏡面仕上げを行った観察面を光学顕微鏡にて画像の１ピクセルが０．５６４×０．５６４μｍであり、１２８０×９６０ピクセルの画像となるように任意場所の光学顕微鏡写真を撮影する。この時、プレス方向が画像の縦軸となるように写真撮影を行う。その撮影画像をImage- Pro Premier Ver9.3にて測定を行う。まず、「モフォロジカル」タブ中にて「収縮、形状２×２正方形、回数４」にてフィルタをかける。そして、磁性相のみが選択されるように２値化を行い、平均領域長さ、平均領域幅を測定する。ただし、領域幅の値が２ピクセル（１．１２８μｍ）以下の対象物は除外する。それらの値に収縮フィルタ分の減少分４．５１２μｍを加算した値、つまり、（平均領域長さ＋４．５１２μｍ）が平均板幅、（平均領域幅＋４．５１２μｍ）が平均厚みとした。また、平均板幅と平均厚みの比（平均板幅/平均厚み）の平均は、撮影画像１枚の平均板幅と平均厚みを用いて算出した値であり、実施例１では２５枚、実施例２では２７枚、実施例３では３５枚の画像を処理し、表１にはこれらの値の範囲を示した。
　また、プレス後の試料の磁性相（Ｒ２Ｔ１４Ｂ相）の割合（体積率）は、プレス方向と平行となる断面が観察できるような最低３視野以上の複数の観察面における磁性相の平均面積率（面積％）より算出した。プレス後の試料の磁性相（Ｒ２Ｔ１４Ｂ相）の割合（体積率）は、実施例１の試料は５４体積％であり、実施例の試料は５９体積％であり、実施例３の試料は６４体積％であった。 The measurement method of the average thickness and the average plate width is as follows. First, the sample is cut and polished so that the cross section parallel to the pressing direction can be observed. The mirror-finished observation surface is photographed with an optical microscope at any location so that one pixel of the image is 0.564 x 0.564 μm, and the image is 1280 x 960 pixels. At this time, the photograph is taken so that the pressing direction is the vertical axis of the image. The photographed image is measured with Image-Pro Premier Ver9.3. First, in the "Morphological" tab, a filter is applied with "Shrinkage, shape 2 x 2 square, number of times 4". Then, binarization is performed so that only the magnetic phase is selected, and the average region length and average region width are measured. However, objects with a region width value of 2 pixels (1.128 μm) or less are excluded. The values obtained by adding the reduction of 4.512 μm due to the shrinkage filter to these values, that is, (average region length + 4.512 μm) is the average plate width, and (average region width + 4.512 μm) is the average thickness. In addition, the average ratio of the average plate width to the average thickness (average plate width/average thickness) was calculated using the average plate width and average thickness of one captured image. 25 images were processed in Example 1, 27 images in Example 2, and 35 images in Example 3, and the ranges of these values are shown in Table 1.
The ratio ( volume fraction) of the magnetic phase (R2T14B phase ) in the samples after pressing was calculated from the average area fraction (area %) of the magnetic phase in a plurality of observation planes of at least three fields of view in which a cross section parallel to the pressing direction could be observed. The ratio (volume fraction) of the magnetic phase ( R2T14B phase ) in the samples after pressing was 54 volume % for the sample of Example 1, 59 volume % for the sample of the Example, and 64 volume % for the sample of Example 3.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　実施例１－３の試料では、平均厚みが７～１２μｍ、平均板幅が１０～３５μｍ以内であることが確認された。また、平均板幅と平均厚みの比（平均板幅／平均厚み）は、１．５以上であることが確認された。 In the samples of Examples 1-3, it was confirmed that the average thickness was 7 to 12 μm and the average plate width was within the range of 10 to 35 μm. In addition, it was confirmed that the ratio of the average plate width to the average thickness (average plate width/average thickness) was 1.5 or more.
　実施例１－３の試料の磁石の特性を示すＪＨ曲線を図４に示す。実施例１（磁性相５４体積％）、実施例２（磁性相５９体積％）、実施例３（磁性相６４体積％）は、高残留磁化を有しており、保磁力も出ており、飽和磁化が０．８Ｔ以上の異方性磁石となっていることが確認された。 The JH curves showing the magnetic properties of the samples of Examples 1-3 are shown in Figure 4. Example 1 (magnetic phase 54% by volume), Example 2 (magnetic phase 59% by volume), and Example 3 (magnetic phase 64% by volume) were confirmed to have high residual magnetization, coercive force, and to be anisotropic magnets with saturation magnetization of 0.8 T or more.
　＜実施例４＞
　磁性相（Ｒ２Ｔ１４Ｂ）としてＮｄ２Ｆｅ１４Ｂ、非磁性相（ＲＣｕ）としてＮｄ－３０原子％Ｃｕ合金を選択した。磁性相（Ｎｄ2Ｆｅ14Ｂ）および非磁性相（Ｎｄ－３０原子％）の割合が、磁性相６４体積％となるように母合金を秤量した。そして、これを不活性雰囲気中高周波溶解（溶湯温度１６００℃）にて溶解させ、BN離型剤を厚く塗布した炭素鋼鋳型に鋳込むことによりφ６ｍｍの丸棒状の混合物を作製した。この鋳造により、磁性相（Ｎｄ２Ｆｅ１４Ｂ）および非磁性相（Ｎｄ－３０原子％Ｃｕ）からなる丸棒状の混合物を準備した。 Example 4
Nd 2 Fe 14 B was selected as the magnetic phase (R 2 T 14 B), and Nd-30 atomic % Cu alloy was selected as the non-magnetic phase (RCu). The master alloy was weighed so that the ratio of the magnetic phase (Nd 2 Fe 14 B) and the non-magnetic phase (Nd-30 atomic %) was 64 volume % of the magnetic phase. Then, this was melted by high-frequency melting in an inert atmosphere (molten metal temperature 1600 ° C.) and cast into a carbon steel mold thickly coated with a BN mold release agent to produce a round bar-shaped mixture of φ 6 mm. By this casting, a round bar-shaped mixture consisting of the magnetic phase (Nd 2 Fe 14 B) and the non-magnetic phase (Nd-30 atomic % Cu) was prepared.
　この丸棒状の混合物を長さ５ｍｍに切断後、大気中で６２０℃まで加熱し、図５に例示するような金型にて４５０ＭＰａの荷重により丸棒状の混合物を１ｍｍ厚の板状にプレスした（配向処理）。磁石として使用した部分は底の直径６ｍｍの部分である。 This rod-shaped mixture was cut to a length of 5 mm, then heated to 620°C in air and pressed into a plate of 1 mm thickness with a load of 450 MPa using a mold as shown in Figure 5 (orientation treatment). The part used as the magnet was the bottom part with a diameter of 6 mm.
　プレス後の試料の磁性相（Ｒ２Ｔ１４Ｂ相）の割合（体積率）は、プレス方向と平行となる断面が観察できるような観察面３視野における磁性相の平均面積率（面積％）より算出した。プレス後の試料の磁性相（Ｒ２Ｔ１４Ｂ相）の割合（体積率）は６７．６体積％であった。 The ratio ( volume fraction) of the magnetic phase ( R2T14B phase) in the sample after pressing was calculated from the average area fraction (area %) of the magnetic phase in three observation fields where a cross section parallel to the pressing direction could be observed. The ratio (volume fraction) of the magnetic phase ( R2T14B phase) in the sample after pressing was 67.6 volume %.
　実施例４の試料の様々な場所で測定した磁性相（Ｎｄ２Ｆｅ１４Ｂ）の平均厚み、平均板幅、平均板幅／平均厚みの値を表２に示す。 The average thickness, average plate width, and average plate width/average thickness of the magnetic phase (Nd 2 Fe 14 B) measured at various locations on the sample of Example 4 are shown in Table 2.
　なお、平均厚みおよび平均板幅の測定方法は以下の通りである。まず、プレス方向と平行になる断面が観察できるように試料を切断、研磨を行う。鏡面仕上げを行った観察面を走査電子顕微鏡の反射電子像にて画像の１ピクセルが０．１×０．１μｍであり、１２８０×９６０ピクセルの画像となるように任意場所の走査電子顕微鏡写真を撮影する。この時、プレス方向が画像の縦軸となるように写真撮影を行う。その撮影画像をImage- Pro Premier Ver9.3にて測定を行う。まず、「モフォロジカル」タブ中にて「膨張、形状２×２正方形、回数４」にてフィルタをかける。そして、磁性相のみが選択されるように２値化を行い、平均領域長さ、平均領域幅を測定する。ただし、領域幅の値が２ピクセル（０．２μｍ）以下の対象物は除外する。それらの値に膨張フィルタ分の減少分０．８μｍを加算した値、つまり、（平均領域長さ＋０．８μｍ）が平均板幅、（平均領域幅＋０．８μｍ）が平均厚みとした。また、平均板幅と平均厚みの比（平均板幅／平均厚み）の平均は、撮影画像１枚の平均板幅と平均厚みを用いて算出した値であり、２０枚の画像を処理し、表２にはこれらの値の範囲を示した。 The average thickness and average plate width are measured as follows. First, the sample is cut and polished so that a cross section parallel to the pressing direction can be observed. A scanning electron microscope photograph is taken of an arbitrary location of the mirror-finished observation surface so that one pixel of the image is 0.1 x 0.1 μm in the backscattered electron image of the scanning electron microscope, resulting in a 1280 x 960 pixel image. At this time, the photograph is taken so that the pressing direction is the vertical axis of the image. The captured image is measured using Image-Pro Premier Ver9.3. First, a filter is applied in the "Morphological" tab with "Expansion, shape 2 x 2 square, number of times 4". Then, binarization is performed so that only the magnetic phase is selected, and the average region length and average region width are measured. However, objects with a region width value of 2 pixels (0.2 μm) or less are excluded. The values obtained by adding 0.8 μm, the reduction due to the expansion filter, to these values is taken as the average plate width, i.e., (average region length + 0.8 μm) is the average plate width, and (average region width + 0.8 μm) is the average thickness. In addition, the average ratio of the average plate width to the average thickness (average plate width/average thickness) was calculated using the average plate width and average thickness of one captured image; 20 images were processed, and the range of these values is shown in Table 2.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　実施例４の試料では、平均厚みが７～１２μｍ、平均板幅が１０～３５μｍ以内であることが確認された。また、平均板幅と平均厚みの比（平均板幅／平均厚み）は、１．５以上であることが確認された。 In the sample of Example 4, it was confirmed that the average thickness was 7 to 12 μm and the average plate width was within 10 to 35 μm. In addition, it was confirmed that the ratio of the average plate width to the average thickness (average plate width/average thickness) was 1.5 or more.
　実施例４の試料の磁石の特性を示すＪＨ曲線を図６に示す。実施例４（磁性相６７．６体積％）は、高残留磁化を有しており、保磁力も出ており、飽和磁化が０．８Ｔ以上の異方性磁石となっていることが確認された。
 
  6 shows the JH curve indicating the magnetic properties of the sample of Example 4. It was confirmed that Example 4 (magnetic phase 67.6% by volume) had high remanent magnetization, exhibited coercive force, and was an anisotropic magnet with a saturation magnetization of 0.8 T or more.

Claims (8)

  1. 　板状の磁性相と、非磁性相とからなる異方性希土類磁石であって、
    　前記磁性相は、Ｒ２Ｔ１４Ｂで表される組成を有し（ただし、Ｒは、その総量を１００原子％としたときに、ＮｄまたはＰｒのうちの一方または両方が５０原子％以上含まれる１種または２種以上の希土類元素を示し、Ｔは、Ｆｅ、または、ＦｅおよびＣｏを含む１種または２種以上の遷移金属元素を示す）、
    　前記非磁性相は、ＲＣｕで表される組成を有し（ただし、Ｒは、その総量を１００原子％としたときに、ＮｄまたはＰｒのうちの一方または両方が５０原子％以上含まれる１種または２種以上の希土類元素を示す）、かつ、Ｃｕが６原子％以上８０原子％以下であり、
    　前記磁性相の割合が５１体積％以上６９体積％未満であり、
    　飽和磁化が０．８Ｔ以上である
    ことを特徴とする異方性希土類磁石。     An anisotropic rare earth magnet consisting of a plate-shaped magnetic phase and a non-magnetic phase,
    The magnetic phase has a composition represented by R2T14B (where R represents one or more rare earth elements, one or both of which are Nd and/or Pr, and T represents one or more transition metal elements including Fe, or Fe and Co, when the total amount of R is taken as 100 atomic %);
    The non-magnetic phase has a composition represented by RCu (where R represents one or more rare earth elements, one or both of which are Nd and Pr, and each of which accounts for 50 atomic % or more when the total amount of R is taken as 100 atomic %), and Cu is 6 atomic % or more and 80 atomic % or less;
    The ratio of the magnetic phase is 51% by volume or more and less than 69% by volume,
    An anisotropic rare earth magnet having a saturation magnetization of 0.8 T or more.
  2. 　前記磁性相は、平均厚みが７～１２μｍであり、かつ、平均板幅が１０～３５μｍである
    ことを特徴とする請求項１の異方性希土類磁石。     2. The anisotropic rare earth magnet according to claim 1, wherein the magnetic phase has an average thickness of 7 to 12 μm and an average plate width of 10 to 35 μm.
  3. 　前記磁性相の平均板幅と平均厚みの比（平均板幅／平均厚み）が１．５以上１５以下である
    ことを特徴とする請求項１の異方性希土類磁石。     2. The anisotropic rare earth magnet according to claim 1, wherein the ratio of the average plate width to the average thickness of said magnetic phase (average plate width/average thickness) is 1.5 or more and 15 or less.
  4. 　前記磁性相の融点が１０００℃以上１３００℃以下であり、前記非磁性相の融点が４００℃～９００℃である
    ことを特徴とする請求項１の異方性希土類磁石。     2. The anisotropic rare earth magnet according to claim 1, wherein the melting point of said magnetic phase is from 1000°C to 1300°C, and the melting point of said non-magnetic phase is from 400°C to 900°C.
  5. 　飽和磁化が０．８Ｔ以上である異方性希土類磁石の製造方法であって、
    　板状の磁性相と、非磁性相とからなる混合物を加熱状態で配向処理する工程を含み、
    　前記磁性相は、Ｒ２Ｔ１４Ｂで表される組成を有し（ただし、Ｒは、その総量を１００原子％としたときに、ＮｄまたはＰｒのうちの一方または両方が５０原子％以上含まれる１種または２種以上の希土類元素を示し、Ｔは、Ｆｅ、または、ＦｅおよびＣｏを含む１種または２種以上の遷移金属元素を示す）、
    　前記非磁性相は、ＲＣｕで表される組成を有し（ただし、Ｒは、その総量を１００原子％としたときに、ＮｄまたはＰｒのうちの一方または両方が５０原子％以上含まれる１種または２種以上の希土類元素を示す）、かつ、Ｃｕが６原子％以上８０原子％以下であり、
    　前記磁性相の割合が５１体積％以上６９体積％未満であり、
    　前記混合物の加熱温度は、前記非磁性相の融点以上、かつ、前記磁性相の融点以下である
    ことを特徴とする異方性希土類磁石の製造方法。     A method for producing an anisotropic rare earth magnet having a saturation magnetization of 0.8 T or more, comprising the steps of:
    The method includes a step of subjecting a mixture of a plate-like magnetic phase and a non-magnetic phase to an orientation treatment under heating,
    The magnetic phase has a composition represented by R2T14B (where R represents one or more rare earth elements, one or both of which are Nd and/or Pr, and T represents one or more transition metal elements including Fe, or Fe and Co, when the total amount of R is taken as 100 atomic %);
    The non-magnetic phase has a composition represented by RCu (where R represents one or more rare earth elements, one or both of which are Nd and Pr, and each of which accounts for 50 atomic % or more when the total amount of R is taken as 100 atomic %), and Cu is 6 atomic % or more and 80 atomic % or less;
    The ratio of the magnetic phase is 51 volume % or more and less than 69 volume %,
    A method for producing an anisotropic rare earth magnet, wherein the mixture is heated to a temperature equal to or higher than the melting point of the nonmagnetic phase and equal to or lower than the melting point of the magnetic phase.
  6. 　前記配向処理後において、前記磁性相は、平均厚みが７～１２μｍであり、かつ、平均板幅が１０～３５μｍである
    ことを特徴とする請求項５の異方性希土類磁石の製造方法。     6. The method for producing an anisotropic rare earth magnet according to claim 5, wherein after the orientation treatment, the magnetic phase has an average thickness of 7 to 12 μm and an average plate width of 10 to 35 μm.
  7. 　前記配向処理後において、前記磁性相は、平均板幅と平均厚みの比（平均板幅／平均厚み）が１．５以上１５以下である
    ことを特徴とする請求項５の異方性希土類磁石の製造方法。     6. The method for producing an anisotropic rare earth magnet according to claim 5, wherein after the orientation treatment, the magnetic phase has a ratio of average plate width to average thickness (average plate width/average thickness) of 1.5 or more and 15 or less.
  8. 　前記磁性相の融点が１０００℃以上１３００℃以下であり、前記非磁性相の融点が４００℃～９００℃である
    ことを特徴とする請求項５の異方性希土類磁石の製造方法。
     
          6. The method for producing an anisotropic rare earth magnet according to claim 5, wherein the melting point of said magnetic phase is from 1000°C to 1300°C, and the melting point of said non-magnetic phase is from 400°C to 900°C.
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JP2005093731A (en) * 2003-09-17 2005-04-07 Daido Steel Co Ltd Anisotropic magnet, its manufacturing method, and motor using it
WO2012114530A1 (en) * 2011-02-21 2012-08-30 トヨタ自動車株式会社 Production method for rare-earth magnet
JP2013149862A (en) * 2012-01-20 2013-08-01 Toyota Motor Corp Method of manufacturing rare earth magnet
JP2013175705A (en) * 2012-01-26 2013-09-05 Toyota Motor Corp Method of manufacturing rare earth magnet
JP2018073873A (en) * 2016-10-25 2018-05-10 株式会社豊田中央研究所 Rare earth magnet and method for manufacturing the same
JP2019047021A (en) * 2017-09-05 2019-03-22 住友電気工業株式会社 Method for manufacturing rare earth magnet

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005093731A (en) * 2003-09-17 2005-04-07 Daido Steel Co Ltd Anisotropic magnet, its manufacturing method, and motor using it
WO2012114530A1 (en) * 2011-02-21 2012-08-30 トヨタ自動車株式会社 Production method for rare-earth magnet
JP2013149862A (en) * 2012-01-20 2013-08-01 Toyota Motor Corp Method of manufacturing rare earth magnet
JP2013175705A (en) * 2012-01-26 2013-09-05 Toyota Motor Corp Method of manufacturing rare earth magnet
JP2018073873A (en) * 2016-10-25 2018-05-10 株式会社豊田中央研究所 Rare earth magnet and method for manufacturing the same
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