WO2018235856A1 - Permanent magnet - Google Patents

Permanent magnet Download PDF

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Publication number
WO2018235856A1
WO2018235856A1 PCT/JP2018/023430 JP2018023430W WO2018235856A1 WO 2018235856 A1 WO2018235856 A1 WO 2018235856A1 JP 2018023430 W JP2018023430 W JP 2018023430W WO 2018235856 A1 WO2018235856 A1 WO 2018235856A1
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permanent magnet
phase
concentration
feni
alloy
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PCT/JP2018/023430
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French (fr)
Japanese (ja)
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小室　又洋
雅史 能島
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株式会社日立製作所
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Publication of WO2018235856A1 publication Critical patent/WO2018235856A1/en

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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C19/00—Alloys based on nickel or cobalt
    • C22C19/03—Alloys based on nickel or cobalt based on nickel
    • 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
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C10/00—Solid state diffusion of only metal elements or silicon into metallic material surfaces
    • C23C10/28—Solid state diffusion of only metal elements or silicon into metallic material surfaces using solids, e.g. powders, pastes
    • C23C10/34—Embedding in a powder mixture, i.e. pack cementation
    • C23C10/36—Embedding in a powder mixture, i.e. pack cementation only one element being diffused
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/60—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using solids, e.g. powders, pastes
    • C23C8/62—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using solids, e.g. powders, pastes only one element being applied
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/60—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using solids, e.g. powders, pastes
    • C23C8/62—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using solids, e.g. powders, pastes only one element being applied
    • C23C8/64—Carburising
    • C23C8/66—Carburising of ferrous surfaces
    • 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

Definitions

  • the present invention relates to permanent magnets that do not use rare earth elements.
  • rare earth elements there are neodymium permanent magnets and samarium cobalt permanent magnets. Since rare earth elements (rare earth elements, also simply referred to as rare earths) are used for these permanent magnet materials, technology for reducing their usage has been studied from the viewpoint of resource stability, resource security assurance, and price stability. The As a result, FeNi alloys have been developed as permanent magnet materials that do not use rare earth elements.
  • Patent Document 1 describes a method of producing FeNi alloy powder as a powder for permanent magnet without using rare earth. Further, Patent Document 2 describes a method of manufacturing an L10 type FeNi ordered alloy and a L10 type FeNi ordered alloy. Further, Patent Document 3 describes a Cu 3 Au type ordered alloy.
  • an object of the present invention is to provide a low cost permanent magnet which does not contain a rare earth element as a constituent element and has higher magnetic properties (for example, maximum energy product, heat resistance, coercivity) than conventional ordered alloy permanent magnets. To provide.
  • One aspect of the present invention is a permanent magnet containing no rare earth element, containing a FeNi ordered phase in which a third element other than iron (Fe) and nickel (Ni) is diffused, and the third element is Carbon (C), nitrogen (N) or cobalt (Co), the concentration of the third element decreases from the surface to the inside of the permanent magnet, and / or the grains of the FeNi ordered phase It is an object of the present invention to provide a permanent magnet characterized by decreasing from the surface to the inside.
  • the present invention can make the following improvements and changes in the above-mentioned permanent magnet.
  • the degree of order of the FeNi ordered phase is in the range of 0.05 or more and 1.0 or less.
  • the third element is carbon, and the carbon concentration of the surface is 0.5% by weight or more and 2% by weight or less.
  • the third element is nitrogen, and the nitrogen concentration of the surface is 1.0% by weight or more and 2% by weight or less.
  • the third element is cobalt, and the cobalt concentration on the surface is 0.2% by weight or more and 10% by weight or less.
  • the present invention provides a low cost permanent magnet which does not contain a rare earth element as a constituent element and has higher magnetic properties (for example, maximum energy product, heat resistance, coercivity) than conventional ordered alloy permanent magnets. can do.
  • L10 type FeNi ordered alloy is expected as a material of the rare earth free permanent magnet.
  • the permanent magnet of the conventional ordered alloy system has reached the level to which the magnet characteristic (for example, maximum energy product, heat resistance, coercive force) is expected enough.
  • conventional ordered alloy materials have not been developed into materials suitable for mass production of permanent magnets.
  • the coercive force of the permanent magnet is improved by increasing the magnetocrystalline anisotropic energy
  • the heat resistance temperature of the permanent magnet is improved by increasing the magnetic transformation point ( 3) It is generally known that increasing the saturation flux density and residual flux density improves the maximum energy product of the permanent magnet.
  • the present inventors introduce a third element other than Fe and Ni into the L10 type FeNi ordered phase to give distortion to the crystal lattice. I thought.
  • a third element other than Fe and Ni into the L10 type FeNi ordered phase to give distortion to the crystal lattice.
  • the conventional technology of a regular alloy based permanent magnet there is no example of a technology for causing the third element to actively infiltrate the crystal lattice of the regular phase.
  • the inventors of the present invention have intensively studied a technique (a technique for introducing a strain into the ordered phase) in which the third element is caused to enter the L10 type FeNi ordered phase at low cost.
  • C, N, or Co is used as the third element, and the third element is introduced into the FeNi crystal grains by a method using grain boundary diffusion / bulk diffusion to FeNi crystal grains and phase transformation of FeNi crystal grains.
  • the inventors have found a technique for applying strain to the crystal lattice of the FeNi ordered phase (increasing the magnetocrystalline anisotropy energy of the ordered phase).
  • the present invention has been completed based on the findings.
  • C, N, Co or the like as the third element to be introduced into the L10 type FeNi ordered phase.
  • C atoms and N atoms easily intrude into interstitial sites in a disordered phase crystal lattice, and increase the internal energy of the crystal lattice.
  • C atoms and N atoms have a smaller atomic radius and a larger diffusion coefficient than metal atoms such as Fe atoms and Ni atoms, so they easily enter the crystal lattice composed of the metal atoms. Strain the crystal lattice. When the increase of the internal energy of the crystal is increased by the introduction of lattice strain, a driving force of atomic diffusion (atomic rearrangement) is generated.
  • tempering at a low temperature of about 200 ° C. causes a change in crystal structure (phase transformation).
  • phase transformation atomic diffusion causing phase transformation at low temperature is induced by atomic penetration of interstitial elements (realignment (atomic diffusion) of Fe and Ni atoms is accelerated by the penetration of C and N atoms). It can be said.
  • the permanent magnet of the present invention contains an FeNi ordered phase having a predetermined degree of order or more.
  • the degree of order is a value calculated from the peak intensity of (001) plane of FeNi phase by X-ray diffraction (XRD) measurement, and the sum of FeNi ordered phase and FeNi disordered phase Defined as the ratio of FeNi ordered phase to.
  • XRD X-ray diffraction
  • a degree of order less than 0.5 means that the FeNi disordered phase is more than the FeNi ordered phase
  • a degree of order greater than 0.5 means that the FeNi ordered phase is greater than the FeNi disordered phase.
  • the degree of order in the range of 0.05 or more and 1.0 or less.
  • the anisotropic magnetic field (coercive force) of the permanent magnet becomes 10 kOe ( ⁇ 796 kA / m) or more, and the maximum energy product becomes 20 MGOe ( ⁇ 159 kJ / m 3 ) or more. If the degree of order is less than 0.05, the coercivity of the permanent magnet will be less than 10 kOe, making it easy to carry out thermal demagnetization.
  • the FeNi crystal lattice constituting the FeNi ordered phase expands.
  • the unit cell volume expands by 0.5 to 10%.
  • the unit cell volume can be calculated from the spacing of the FeNi phase by XRD measurement.
  • the penetration of C atoms and N atoms into the FeNi alloy can be achieved, for example, by diffusing atoms generated by the decomposition of acetylene gas and amine gas into the interior of the permanent magnet.
  • a concentration difference of C atoms and N atoms occurs between the surface and the inside of the permanent magnet.
  • a difference in concentration of C atoms and N atoms occurs between the grain boundaries of the austenite phase present inside the permanent magnet and the grain boundaries (grain surfaces).
  • Example 1 is an example of a permanent magnet using an Fe-25 wt% Ni alloy.
  • a separately prepared Fe-25 wt% Ni alloy base material is rolled at a working ratio of 50% to obtain a plate of 1 mm thickness.
  • an Fe 3 C powder (particle size 15 ⁇ m or less) is applied to a surface of the Fe-25 wt% Ni alloy plate to a thickness of 100 ⁇ m, and heated to 1000 ° C. in an argon (Ar) gas atmosphere. After holding at 1000 ° C. for 100 minutes, quenching is performed in an Ar gas atmosphere.
  • the Fe-25 wt% Ni alloy becomes an austenitic phase ( ⁇ phase) at 1000 ° C.
  • ⁇ phase an austenitic phase
  • the C component diffuses into the ⁇ phase from the Fe 3 C powder, and the C component forms a solid solution in the ⁇ phase (for example, 1 wt% solid solution).
  • ⁇ phase a metastable phase containing 1% by weight of the C component.
  • the amount of carbon to be dissolved can be adjusted by adjusting the heating temperature and / or the holding time in the diffusion and infiltration process.
  • the plate material in which the C component is dissolved is tempered (held at 100 ° C. for 2 hours), the FeNi ordered phase is formed and grown.
  • X-ray diffraction measurement is performed on the obtained sample, a diffraction peak indicating the formation and growth of the FeNi ordered phase can be confirmed.
  • the difference in carbon concentration between grain boundaries and intragrains affects the microstructure during cooling. Since the carbon concentration is high at grain boundaries, a martensitic phase ( ⁇ ′ phase) of high carbon concentration is formed in the vicinity of grain boundaries (grain boundary region) in the cooling process. For this reason, in the formation and growth of the FeNi ordered phase in the tempering step, a difference occurs between the carbon concentration of the FeNi ordered phase near the grain boundaries and the carbon concentration of the FeNi ordered phase in the grains.
  • the degree of order of the FeNi ordered phase near the grain boundaries with high C concentration is the FeNi order in the grains. Higher than the regularity of the phase.
  • the degree of order can be adjusted by adjusting the heating temperature and / or the holding time in the tempering step.
  • FIG. 1 is an example of a graph showing the relationship between the degree of order and the anisotropic magnetic field.
  • the degree of order is a value calculated from the peak intensity of the (001) plane of the FeNi phase by XRD measurement, and the ratio of the FeNi ordered phase to the total of the FeNi ordered phase and the FeNi disordered phase Is an indicator of
  • a degree of order less than 0.5 means that the FeNi disordered phase is greater than the FeNi ordered phase
  • a degree of order greater than 0.5 means that the FeNi ordered phase is greater than the FeNi disordered phase.
  • the degree of order of 1.0 corresponds to the state in which there is no FeNi irregular phase (all in the state of being an FeNi ordered phase).
  • FIG. 1 shows the results of examining the relationship between the degree of order and the anisotropic magnetic field using a sample having a C concentration of 0.1 wt% and a sample having a C concentration of 1.0 wt%.
  • the degree of order is less than 0.01
  • the anisotropic magnetic field is 5 kOe or less in both the 0.1 wt% C sample and the 1.0 wt% C sample. If the anisotropic magnetic field of the permanent magnet is less than 10 kOe, heat demagnetization is likely to occur. In other words, in the present invention, 10 kOe or more is determined as a pass as the anisotropic magnetic field of the permanent magnet.
  • the anisotropic magnetic field reaches 10 kOe in both the 0.1 wt% C sample and the 1.0 wt% C sample. As the degree of order increases, the anisotropic magnetic field also tends to increase, and it has been found that the range of the degree of order preferred in the present embodiment is 0.05 or more.
  • the anisotropic magnetic field should be 10 kOe or more in both the sample with a C concentration of 0.1 wt% and the sample with a 1.0 wt% C even when the degree of order exceeds 0.3. Have confirmed.
  • a sample with a 1.0 wt% C and an order of 0.05 has an anisotropic magnetic field of 30 kOe, a coercive force of 10 to 15 kOe, and a maximum energy product of 20 to 21 MGOe. It is considered that this is because in the FeNi ordered phase having a high carbon concentration, the fcc (face-centered cubic) structure changes to a bct (body-centered tetragonal) structure due to distortion of the crystal lattice due to interstitial carbon.
  • FIG. 2 is an example of a graph showing the relationship between C concentration and coercivity. This is the result of examining the coercivity of the obtained permanent magnet by adjusting the C concentration by adjusting the conditions of the diffusion / infiltration step and the tempering step of Example 1.
  • the coercivity of the 0.1 wt% C sample is 0.3 kOe.
  • the coercivity of the 0.5 wt% C sample is 0.5 kOe.
  • the coercivity increases as the C concentration increases up to 1.2 wt% C, and the coercivity decreases as it exceeds 1.2 wt% C.
  • the coercive force is increased in the range of 0.5 to 2% by weight C as compared with the case of less than 0.5% by weight C.
  • the range of 1 to 1.5 wt% C is particularly preferable, and a coercive force of 5 kOe or more can be confirmed.
  • the maximum energy product is 20 MGOe or more.
  • FIG. 3 is a schematic view showing an example of the microstructure of the cross section of the permanent magnet of the present invention.
  • the permanent magnet of the present invention has a microstructure in which a large number of crystal grains 1 are in contact via grain boundaries (abbreviated as grain boundaries) 2.
  • the C concentration in grain boundary 2 is 1.5 to 20 times the C concentration in crystal grain 1 and the FeNi order in the region (referred to as grain boundary region) within 100 nm thickness from grain boundary 2 to crystal grain 1 is the crystal It is higher than the FeNi periodicity inside grain 1. Since the FeNi order in the grain boundary region is high, the magnetocrystalline anisotropy energy becomes large, and high coercivity can be expressed.
  • Example 1 As a comparative material of Example 1, instead of using an Fe-25 wt% Ni-1 wt% C alloy base material containing 1 wt% of carbon from the beginning, a sample not subjected to Fe 3 C powder coating was prepared. Specifically, a rolling process is carried out at a working ratio of 50% with respect to an Fe-25 wt% Ni-1 wt% C alloy base material to obtain a plate having a thickness of 1 mm. Next, after heating to 1000 ° C. and holding for 2 hours, quenching is performed in an Ar gas atmosphere.
  • the Fe-25 wt% Ni-1 wt% C alloy becomes an austenitic phase at 1000 ° C. and becomes a martensitic phase upon quenching. Thereafter, the plate material is tempered at 100 ° C. to form and grow an FeNi ordered phase.
  • the C component When the C component is solid-solved at the stage of the alloy base material, the C component is distributed substantially equally in the inside of the alloy base material, so that there is no difference in C concentration between the inside of the crystal grain and the grain boundary. As a result, the degree of order becomes almost the same in the interior of the crystal grain and the grain boundary, and a large magnetocrystalline anisotropy energy can not be obtained. Therefore, it is considered that the coercivity and the maximum energy product did not improve.
  • Example 2 is an example in which the influence of the Ni concentration of the alloy base material on the anisotropic magnetic field of the permanent magnet was investigated.
  • FIG. 4 is an example of a graph showing the relationship between the Ni concentration and the anisotropic magnetic field. As shown in FIG. 4, when the Ni concentration is in the range of 25 to 55% by weight, it can be confirmed that the anisotropic magnetic field is 15 kOe or more and strong magnetic anisotropy can be obtained. In this case, the maximum energy product is 21 MGOe or more.
  • Example 3 describes an example of a powder for a permanent magnet using an Fe-30 wt% Ni alloy and a permanent magnet using the powder.
  • a separately prepared Fe-30% by weight Ni alloy base material is rolled at a working ratio of 50% to obtain a plate having a thickness of 1 mm.
  • Fe 3 C powder particle size 15 ⁇ m or less
  • the particle size of the Fe 3 C powder is 15 ⁇ m or less.
  • the coating thickness is 100 ⁇ m.
  • quenching is performed in an Ar gas atmosphere.
  • the cooling rate of the quenching is 20 to 50 ° C./second. Oxidation in the material can be prevented by cooling in an Ar gas atmosphere, and the oxygen concentration at the grain boundary of the alloy crystal can be made 100 ppm or less. This promotes the diffusion of the C component.
  • the Fe-30 wt% Ni alloy becomes an austenitic single phase at 1000 ° C.
  • the C component diffuses into the ⁇ phase from the Fe 3 C powder, and the C component dissolves in the ⁇ phase.
  • rapid cooling after temperature rising and holding it is not transformed into the ⁇ phase in the cooling process, and the ⁇ phase is obtained as a single phase.
  • the C concentration in the grain boundary is higher than the C concentration in the grain, and the grain boundary is mechanically more brittle than the grain. Then, when the rapidly cooled plate material is crushed, a powder having a particle diameter of 5 to 10 ⁇ m is obtained.
  • the powder is subjected to a tempering step (after being kept at 200 ° C. for 10 hours, and then cooling) to obtain a powder for permanent magnet.
  • each atom of Fe, Ni and C rearranges in the direction of the magnetic field so as to maximize the magnetization, and the easy magnetization direction of the powder becomes parallel to the direction of the magnetic field. It is thus possible to increase the maximum energy product.
  • the surface of the powder particle has a C concentration higher than that of the inside of the particle and is 1.5 to 2% by weight.
  • the C concentration distribution has a decreasing distribution from the surface to the inside with a concentration gradient of 0.01 to 1 wt% C ⁇ m ⁇ 1 .
  • the degree of order near the surface of the powder particles is higher than the average degree of order inside the particles.
  • the crystal structure of the powder particles is fcc, bct or mixed phases thereof.
  • the Curie point is 540 ° C., and the decomposition temperature of the FeNi ordered phase is below this temperature.
  • the powder is oriented in a magnetic field (for example, in 10 kOe) and then pressurized at a pressure of 10 t / cm 2 to form a compact.
  • the molded body is heated to 250 ° C. in a magnetic field of 1.0 T and held for 10 hours, and then slowly cooled (for example, cooled at 1 ° C./min or less) in the magnetic field to produce a permanent magnet.
  • the applied magnetic field direction is parallel to the orientation magnetic field direction of the powder.
  • the magnetic properties of the obtained permanent magnet at 20 ° C. are a residual magnetic flux density of 1.2 T, a coercive force of 9 kOe, and a maximum energy product of 22 MGOe.
  • Example 4 is an example of a permanent magnet using Fe 4 N powder instead of the Fe 3 C powder used in Example 1.
  • Example 2 The same Fe-25% by weight Ni alloy base material as in Example 1 is rolled at a working ratio of 50% to obtain a plate having a thickness of 0.5 mm.
  • an Fe 4 N powder (particle size of 15 ⁇ m or less) is applied to a surface of the Fe-25 wt% Ni alloy plate to a thickness of 100 ⁇ m, and heated to 900 ° C. in an Ar gas atmosphere. After holding at 900 ° C. for 100 minutes, quenching is performed in an Ar gas atmosphere.
  • the Fe-25 wt% Ni alloy becomes austenite single phase at 900 ° C.
  • the N component diffuses into the ⁇ phase from the Fe 4 N powder, and the N component forms a solid solution in the ⁇ phase (for example, 0.8 wt% solid solution).
  • a solid solution in the ⁇ phase for example, 0.8 wt% solid solution.
  • the amount of nitrogen to be dissolved can be adjusted by adjusting the heating temperature and / or the holding time in the diffusion and infiltration process.
  • the plate material in which the N component is dissolved is tempered (held at 100 ° C. for 2 hours), the FeNi ordered phase is formed and grown.
  • XRD measurement of the obtained sample it is possible to confirm a diffraction peak indicating the formation and growth of the FeNi ordered phase.
  • the grain boundary has a nitrogen concentration higher than that in the grain.
  • the concentration of nitrogen at grain boundaries reaches 1.5 to 20 times the concentration of nitrogen in grains.
  • the difference in nitrogen concentration between grain boundaries and intragrains affects the microstructure during cooling. Since the nitrogen concentration is high at grain boundaries, a martensitic phase of high nitrogen concentration is formed in the vicinity of grain boundaries in the cooling process. For this reason, in the formation and growth of the FeNi ordered phase in the tempering step, a difference occurs between the nitrogen concentration of the FeNi ordered phase near the grain boundaries and the nitrogen concentration of the FeNi ordered phase in the grains.
  • the degree of order of the FeNi ordered phase near the grain boundary where the N concentration is high is the FeNi ordered phase within the grains. Higher than the regularity of.
  • the degree of order can be adjusted by adjusting the heating temperature and / or the holding time in the tempering step.
  • a sample with 0.8 wt% N and a regularity of 0.05 exhibits an anisotropic magnetic field of 25 kOe. This is considered to be because in the FeNi ordered phase having a high nitrogen concentration, the fcc structure is changed to the bct structure due to the strain of the crystal lattice due to interstitial nitrogen.
  • the permanent magnet After heating at 250 ° C. in a magnetic field of 1.0 T and holding for 10 hours with respect to a plate material sample of 0.8 wt% N and regularity 0.05, the permanent magnet is manufactured by slow cooling in the magnetic field. As a result of evaluating the maximum energy product of the permanent magnet, it was 21 MGOe. Moreover, the Curie point was 570 ° C.
  • FIG. 5 is an example of a graph showing the relationship between the N concentration and the coercivity. This is the result of examining the coercivity of the obtained permanent magnet by adjusting the N concentration by adjusting the conditions of the diffusion / infiltration step and the tempering step.
  • the coercivity increases as the N concentration increases up to 1.5 wt% N, and the coercivity decreases as it exceeds 1.5 wt% N.
  • the coercive force is increased in the range of 0.4 to 2% by weight N more than the case of less than 0.4% by weight N.
  • the range of 1 to 2 wt% N is preferable, and the coercivity is 5 kOe or more.
  • the range of 1.2 to 1.5 wt% N is more preferable, and the coercive force is 10 kOe or more.
  • the maximum energy product is 20 to 25 MGOe.
  • the same magnetizing step as described above is performed on a plate material sample having 1% by weight N and a regularity of 0.05 to produce a permanent magnet.
  • the maximum energy product of the permanent magnet it was 10 MGOe.
  • the Curie point was 540 degreeC.
  • the FeNiN permanent magnet Since the Curie point of the FeNiN permanent magnet is considerably higher than the Curie point (310 ° C.) of the neodymium permanent magnet, it can be said that the FeNiN permanent magnet has high heat resistance.
  • Example 4 As a comparative material of Example 4, a sample without Fe 4 N powder coating was prepared instead of using an Fe-25 wt% Ni-1 wt% N alloy base material containing 1 wt% nitrogen from the beginning. Specifically, rolling is performed at a working ratio of 50% with respect to an Fe-25 wt% Ni-1 wt% N alloy base material to obtain a plate having a thickness of 1 mm. Next, after heating to 900 ° C. and holding for 2 hours, quenching is performed in an Ar gas atmosphere.
  • the Fe-25 wt% Ni-1 wt% N alloy becomes an austenitic phase at 900 ° C. and a martensitic phase upon quenching. Thereafter, the plate material is tempered at 100 ° C. to form and grow an FeNi ordered phase.
  • the N component When the N component is solid-solved at the stage of the alloy base material, the N component is distributed substantially equally in the inside of the alloy base material, so that there is no difference in N concentration between the inside of the crystal grains and the grain boundaries. In other words, the N component is not localized at grain boundaries. It is considered that the driving force of atomic diffusion (rearrangement) of Fe atoms and Ni atoms due to the penetration of N atoms is also reduced, and the coercivity and the maximum energy product have not been improved, since the overall N concentration is low.
  • a grain boundary is defined as a boundary in which the difference in crystal orientation between adjacent crystal grains is 15 degrees or more.
  • the crystal lattice in the range of 0.1 ⁇ m or less in thickness from this boundary (grain boundary) is susceptible to the grain boundary. Therefore, a region having a thickness of 0.1 ⁇ m or less from the grain boundary to the crystal grain center side is defined as a grain boundary region.
  • the diffusion speed is different between the crystal grain and the grain boundary of the polycrystal, and the grain boundary diffusion is the inside of the grain. Diffusion rate is faster than diffusion (ie, the amount of diffusion is increased).
  • concentration of the diffusion element on the grain boundary becomes high, a concentration gradient is generated between the grain boundary and the inside of the grain, so that the concentration of the diffusion element easily rises in the grain boundary region. Then, a difference occurs in the diffusion element concentration between the grain boundary region and the inside of the grain (the region from the grain boundary to a thickness of more than 0.1 ⁇ m).
  • the difference in the concentration of the diffusion element means the difference in strain of the crystal lattice, which leads to the difference in driving force of rearrangement of atoms constituting the crystal lattice.
  • a difference in generation / growth of regular phases that is, a difference in regularity
  • the difference in degree of order can be confirmed from the analysis of the electron beam diffraction image of the electron microscope.
  • the degree of order converted from the intensity ratio of the superlattice diffraction point showing the ordered structure of the electron beam diffraction image or the intensity ratio of the diffraction point corresponding to the FeNi disordered phase differs between the grain boundary region and the inside of the grain There is.
  • the intensity of the diffraction point of the (001) plane of the ordered phase in the grain boundary region becomes higher than that in the grain, and the grain boundary region It has been confirmed that the ratio of the intensity of the diffraction point of the (001) plane of the ordered phase to that of the diffraction spot of the (1 1 1) plane of the FeNi disordered phase is higher than that in the grain. .
  • FIG. 6 is an example of a graph showing the relationship between the degree of order (hereinafter referred to as the order of grain boundaries) and the coercivity of grain boundary regions in a Fe-25 wt% Ni alloy. As shown in FIG. 6, there is a strong correlation between the grain boundary order degree and the coercivity, and it is understood that when the grain boundary order degree is 0.7 or more, a coercivity of 20 kOe or more is exhibited.
  • the intragranular order degree is 0.02 and the average order degree of the whole crystal grain is 0.05, but the maximum energy product is 40 MGOe, and the maximum energy product at 150 ° C. It has been confirmed to exceed that of an NdFeB-based sintered permanent magnet (35 MGOe). That is, if the grain boundary order is high, good magnetic properties can be obtained even if the intragranular order and the average order are low.
  • the grain boundary order degree in the FeNi-based alloy is 10 times or more higher than the intra-grain order degree, and the crystal magnetic anisotropy in the grain boundary region is high.
  • the performance of the permanent magnet such as the coercivity and the maximum energy product can be enhanced by enhancing the magnetocrystalline anisotropy in the grain boundary region.
  • Example 6 In Example 6, an example of a cobalt-added permanent magnet will be described with respect to an Fe-35 wt% Ni alloy. Although the examples in which the interstitial elements of carbon and nitrogen are added have been described in the above-described first to fifth embodiments, the same effect can be obtained by adding cobalt. This is because addition of cobalt (Co) increases the magnetocrystalline anisotropy of the Fe-35 wt% Ni alloy.
  • a single roll liquid rapid solidification method in which a separately prepared Fe-35 wt% Ni alloy base material is high-frequency melted in an Ar gas atmosphere and the molten alloy is jetted onto a rotating roll (for example, a roll rotational speed of 3000 rpm)
  • a rotating roll for example, a roll rotational speed of 3000 rpm
  • a 35 wt% Ni alloy powder for example, flat particle powder with a major axis diameter of about 30 ⁇ m
  • the aspect ratio (major axis diameter / minor axis length) of the flat particles is 2 to 10.
  • Co powder for example, a particle size of 10 to 50 nm
  • the mixed powder is oriented in a magnetic field (for example, in a static magnetic field of 10 kOe) and then pressurized at a pressure of 1 t / cm 2 to obtain a porous molded body (for example, bulk density 3 g / cm 3 ) Form.
  • a porous molded body for example, bulk density 3 g / cm 3
  • acetylene gas is introduced and held for 30 minutes, and then quenching is performed, whereby the Co component diffuses and permeates from the surface of the Fe-35 wt% Ni alloy crystal grain A body is obtained.
  • a permanent magnet in which the C component is further diffused and permeated is manufactured.
  • the amount of Co to be diffused and infiltrated can be adjusted by adjusting the heating temperature and / or the holding time in the diffusion and infiltration step.
  • FIG. 7 is an example of a graph showing the relationship between the Co concentration and the maximum energy product. As shown in FIG. 7, it can be seen that the maximum energy product increases in the sample with Co concentration in the range of 0.2 to 10% by weight as compared to the sample without Co.

Abstract

The purpose of the present invention is to provide a low-cost permanent magnet which has higher magnet characteristics than conventional ordered alloy-based permanent magnets, while containing no rare earth element as a constituent element. A permanent magnet according to the present invention contains no rare earth element, and is characterized by containing an FeNi ordered phase in which a third element is diffused. This permanent magnet is also characterized in that: the third element is C, N or Co; and the concentration of the third element decreases from the surface of the permanent magnet toward the inner side thereof and/or the concentration of the third element decreases from the surfaces of crystal grains of the FeNi ordered phase toward the inner sides thereof.

Description

永久磁石permanent magnet
　本発明は、希土類元素を使用しない永久磁石に関するものである。 The present invention relates to permanent magnets that do not use rare earth elements.
　希土類元素を使用する永久磁石の中には、ネオジム永久磁石やサマリウムコバルト永久磁石などがある。これらの永久磁石材料には希土類元素（レアアース元素、単にレアアースとも言う）が使用されているため、資源の安定性、資源セキュリテイ確保、価格安定性の観点から、その使用量低減技術が研究されてきた。その結果、希土類元素を使用しない永久磁石材料としてFeNi合金が開発されている。 Among permanent magnets using rare earth elements, there are neodymium permanent magnets and samarium cobalt permanent magnets. Since rare earth elements (rare earth elements, also simply referred to as rare earths) are used for these permanent magnet materials, technology for reducing their usage has been studied from the viewpoint of resource stability, resource security assurance, and price stability. The As a result, FeNi alloys have been developed as permanent magnet materials that do not use rare earth elements.
　例えば、レアアースを使用しない永久磁石用の粉末としてFeNi合金粉末の製造方法が特許文献１に記載されている。また、特許文献２にはL10型FeNi規則合金の製造方法とL10型FeNi規則合金に関する記載がある。さらに、特許文献３にはCu3Au型規則合金に関する記載がある。 For example, Patent Document 1 describes a method of producing FeNi alloy powder as a powder for permanent magnet without using rare earth. Further, Patent Document 2 describes a method of manufacturing an L10 type FeNi ordered alloy and a L10 type FeNi ordered alloy. Further, Patent Document 3 describes a Cu 3 Au type ordered alloy.
特開２０１４－２３１６２４号公報JP, 2014-231624, A 特開２０１４－１０５３７６号公報JP, 2014-105376, A 特開２００９－０５４７７６号公報JP, 2009-054776, A
　しかしながら、希土類元素を全く使用せずに十分な最大エネルギー積（例えば、20 MGOe）を有する永久磁石は、量産に適した安価な製造プロセスでは残念ながら実現できていない。言い換えると、従来の規則合金系の永久磁石は、製造プロセスが非常に高コストであることに加えて、最大エネルギー積が不十分である、耐熱性が低い、保磁力が小さい等の課題が残っている。したがって、本発明の目的は、構成元素として希土類元素を含まず、従来の規則合金系の永久磁石よりも磁石特性（例えば、最大エネルギー積、耐熱性、保磁力）が高く、低コストの永久磁石を提供することにある。 However, permanent magnets having a sufficient maximum energy product (for example, 20 MGOe) without using any rare earth element are unfortunately not realized in an inexpensive manufacturing process suitable for mass production. In other words, in addition to the very high cost of the manufacturing process, the conventional ordered alloy permanent magnet has problems such as insufficient maximum energy product, low heat resistance, and low coercivity. ing. Therefore, an object of the present invention is to provide a low cost permanent magnet which does not contain a rare earth element as a constituent element and has higher magnetic properties (for example, maximum energy product, heat resistance, coercivity) than conventional ordered alloy permanent magnets. To provide.
　本発明の一態様は、希土類元素を含有しない永久磁石であって、鉄（Fe）およびニッケル（Ni）以外の第３の元素が拡散したFeNi規則相を含有し、前記第３の元素は、炭素（C）、窒素（N）またはコバルト（Co）であり、前記第３の元素の濃度は、前記永久磁石の表面から内部に向かって減少する、および／または前記FeNi規則相の結晶粒の表面から内部に向かって減少することを特徴とする永久磁石、を提供するものである。 One aspect of the present invention is a permanent magnet containing no rare earth element, containing a FeNi ordered phase in which a third element other than iron (Fe) and nickel (Ni) is diffused, and the third element is Carbon (C), nitrogen (N) or cobalt (Co), the concentration of the third element decreases from the surface to the inside of the permanent magnet, and / or the grains of the FeNi ordered phase It is an object of the present invention to provide a permanent magnet characterized by decreasing from the surface to the inside.
　本発明は、上記の永久磁石において、以下のような改良や変更を加えることができる。
（i）前記FeNi規則相の規則度が0.05以上1.0以下の範囲である。
（ii）前記第３の元素が炭素であり、前記表面の炭素濃度が0.5重量％以上2重量％以下である。
（iii）前記第３の元素が窒素であり、前記表面の窒素濃度が1.0重量％以上2重量％以下である。
（iv）前記第３の元素がコバルトであり、前記表面のコバルト濃度が0.2重量％以上10重量％以下である。 The present invention can make the following improvements and changes in the above-mentioned permanent magnet.
(I) The degree of order of the FeNi ordered phase is in the range of 0.05 or more and 1.0 or less.
(Ii) The third element is carbon, and the carbon concentration of the surface is 0.5% by weight or more and 2% by weight or less.
(Iii) The third element is nitrogen, and the nitrogen concentration of the surface is 1.0% by weight or more and 2% by weight or less.
(Iv) The third element is cobalt, and the cobalt concentration on the surface is 0.2% by weight or more and 10% by weight or less.
　本発明によれば、構成元素として希土類元素を含まず、従来の規則合金系の永久磁石よりも磁石特性（例えば、最大エネルギー積、耐熱性、保磁力）が高く、低コストの永久磁石を提供することができる。 According to the present invention, the present invention provides a low cost permanent magnet which does not contain a rare earth element as a constituent element and has higher magnetic properties (for example, maximum energy product, heat resistance, coercivity) than conventional ordered alloy permanent magnets. can do.
規則度と異方性磁場との関係を示すグラフの一例である。It is an example of the graph which shows the relationship between a degree of order and an anisotropic magnetic field. C濃度と保磁力との関係を示すグラフの一例である。It is an example of the graph which shows the relationship between C density | concentration and coercive force. 本発明の永久磁石の断面の微細組織の一例を示す模式図である。It is a schematic diagram which shows an example of the microstructure of the cross section of the permanent magnet of this invention. Ni濃度と異方性磁場との関係を示すグラフの一例である。It is an example of the graph which shows the relationship between Ni concentration and anisotropic magnetic field. N濃度と保磁力との関係を示すグラフの一例である。It is an example of the graph which shows the relationship between N density | concentration and coercive force. Fe-25重量％Ni合金における粒界領域の規則度と保磁力との関係を示すグラフの一例である。It is an example of the graph which shows the relationship between the degree of order of the grain boundary area | region and coercive force in a Fe-25 weight% Ni alloy. Co濃度と最大エネルギー積との関係を示すグラフの一例である。It is an example of the graph which shows the relationship between Co density | concentration and the maximum energy product.
　（本発明の基本思想）
　前述したように、レアアースフリー永久磁石の材料としてL10型FeNi規則合金が期待されている。しかしながら、L10型FeNi規則合金の規則相は単相として作製することが難しいため、現在のところ高コストな化学合成法しか提案されていない。また、従来の規則合金系の永久磁石は、その磁石特性（例えば、最大エネルギー積、耐熱性、保磁力）が期待されるレベルに十分到達しているとは言えない。言い換えると、従来の規則合金材料は永久磁石の量産に適した材料開発には至っていない。 (Basic thought of the present invention)
As described above, L10 type FeNi ordered alloy is expected as a material of the rare earth free permanent magnet. However, since it is difficult to prepare an ordered phase of L10 type FeNi ordered alloy as a single phase, only high cost chemical synthesis methods have been proposed at present. Moreover, it can not be said that the permanent magnet of the conventional ordered alloy system has reached the level to which the magnet characteristic (for example, maximum energy product, heat resistance, coercive force) is expected enough. In other words, conventional ordered alloy materials have not been developed into materials suitable for mass production of permanent magnets.
　一方、永久磁石材料においては、（１）結晶磁気異方性エネルギーを増加させると永久磁石の保磁力が向上する、（２）磁気変態点を上昇させると永久磁石の耐熱温度が向上する、（３）飽和磁束密度および残留磁束密度を増加させると永久磁石の最大エネルギー積が向上する、ことが一般的に知られている。 On the other hand, in the permanent magnet material, (1) the coercive force of the permanent magnet is improved by increasing the magnetocrystalline anisotropic energy, (2) the heat resistance temperature of the permanent magnet is improved by increasing the magnetic transformation point ( 3) It is generally known that increasing the saturation flux density and residual flux density improves the maximum energy product of the permanent magnet.
　本発明者等は、L10型FeNi規則相の結晶磁気異方性エネルギーを増加させるために、L10型FeNi規則相にFeおよびNi以外の第３の元素を浸入させて結晶格子に歪を与えることを考えた。ただし、従来の規則合金系永久磁石の技術において、規則相の結晶格子に積極的に第３の元素を浸入させる技術例はない。 In order to increase the crystal magnetic anisotropy energy of the L10 type FeNi ordered phase, the present inventors introduce a third element other than Fe and Ni into the L10 type FeNi ordered phase to give distortion to the crystal lattice. I thought. However, in the conventional technology of a regular alloy based permanent magnet, there is no example of a technology for causing the third element to actively infiltrate the crystal lattice of the regular phase.
　そこで、本発明者等は、低コストでL10型FeNi規則相に第３の元素を浸入させる技術（規則相への歪導入技術）について鋭意研究した。その結果、第３の元素としてC、NまたはCoを用い、FeNi結晶粒に対する粒界拡散・バルク拡散およびFeNi結晶の相変態を利用する手法によって、該FeNi結晶粒中に第３の元素を導入してFeNi規則相の結晶格子に歪を与える（該規則相の結晶磁気異方性エネルギーを高める）技術を見出した。本発明は当該知見に基づいて完成されたものである。 Therefore, the inventors of the present invention have intensively studied a technique (a technique for introducing a strain into the ordered phase) in which the third element is caused to enter the L10 type FeNi ordered phase at low cost. As a result, C, N, or Co is used as the third element, and the third element is introduced into the FeNi crystal grains by a method using grain boundary diffusion / bulk diffusion to FeNi crystal grains and phase transformation of FeNi crystal grains. Then, the inventors have found a technique for applying strain to the crystal lattice of the FeNi ordered phase (increasing the magnetocrystalline anisotropy energy of the ordered phase). The present invention has been completed based on the findings.
　以下、図面を参照しながら、本発明に係る実施形態をより詳細に説明する。ただし、本発明はここで取り上げた実施形態に限定されることはなく、発明の技術的思想を逸脱しない範囲で、公知技術と適宜組み合わせたり公知技術に基づいて改良したりすることが可能である。また、「重量％」は「wt%」と表記する場合がある。 Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings. However, the present invention is not limited to the embodiments described herein, and can be appropriately combined with the known technology or improved based on the known technology without departing from the technical concept of the invention. . Moreover, "weight%" may be described as "wt%."
　歪導入規則相の形成容易化（すなわち低コスト化）の観点から、L10型FeNi規則相へ侵入させる第３の元素としては、C、N、Co等を用いることが有効である。例えば、C原子およびN原子は、不規則相の結晶格子において格子間位置に浸入し易く、該結晶格子の内部エネルギーを高くする。 From the viewpoint of facilitating formation of a strain introduction ordered phase (that is, cost reduction), it is effective to use C, N, Co or the like as the third element to be introduced into the L10 type FeNi ordered phase. For example, C atoms and N atoms easily intrude into interstitial sites in a disordered phase crystal lattice, and increase the internal energy of the crystal lattice.
　より具体的に言うと、C原子およびN原子は、Fe原子やNi原子などの金属原子よりも原子半径が小さく拡散係数が大きくため、当該金属原子から構成される結晶格子の中に浸入し易く該結晶格子に歪を与える。格子歪の導入により結晶の内部エネルギー増加が増加すると、原子拡散（原子の再配列）の駆動力が発生する。 More specifically, C atoms and N atoms have a smaller atomic radius and a larger diffusion coefficient than metal atoms such as Fe atoms and Ni atoms, so they easily enter the crystal lattice composed of the metal atoms. Strain the crystal lattice. When the increase of the internal energy of the crystal is increased by the introduction of lattice strain, a driving force of atomic diffusion (atomic rearrangement) is generated.
　例えば、C原子やN原子が侵入したマルテンサイト相は準安定相であるため、200℃程度の低温の焼戻しにより結晶構造の変化（相変態）が生じる。言い換えると、低温で相変態を生じさせる原子拡散が侵入型元素の原子浸入によって誘導される（Fe原子およびNi原子の再配列（原子拡散）がC原子やN原子の浸入により加速される）と言うことができる。 For example, since the martensitic phase into which C atoms and N atoms have penetrated is a metastable phase, tempering at a low temperature of about 200 ° C. causes a change in crystal structure (phase transformation). In other words, atomic diffusion causing phase transformation at low temperature is induced by atomic penetration of interstitial elements (realignment (atomic diffusion) of Fe and Ni atoms is accelerated by the penetration of C and N atoms). It can be said.
　Fe原子およびNi原子の再配列（原子拡散）の促進により、永久磁石内でFeNi規則相の成長が促進される。その結果、本発明の永久磁石は、所定の規則度以上のFeNi規則相を含有する。なお、本発明において、規則度とは、Ｘ線回折（XRD）測定によるFeNi相の(0 0 1)面のピーク強度から算出される値であり、FeNi規則相とFeNi不規則相との合計に対するFeNi規則相の割合を示すものと定義する。例えば、規則度0.5未満は、FeNi不規則相がFeNi規則相よりも多いことを意味し、規則度0.5超はFeNi規則相がFeNi不規則相よりも多いことを意味する。 The promotion of the rearrangement (atomic diffusion) of Fe atoms and Ni atoms promotes the growth of the FeNi ordered phase in the permanent magnet. As a result, the permanent magnet of the present invention contains an FeNi ordered phase having a predetermined degree of order or more. In the present invention, the degree of order is a value calculated from the peak intensity of (001) plane of FeNi phase by X-ray diffraction (XRD) measurement, and the sum of FeNi ordered phase and FeNi disordered phase Defined as the ratio of FeNi ordered phase to. For example, a degree of order less than 0.5 means that the FeNi disordered phase is more than the FeNi ordered phase, and a degree of order greater than 0.5 means that the FeNi ordered phase is greater than the FeNi disordered phase.
　本発明者等の種々の研究の結果、規則度を0.05以上1.0以下の範囲とすることが好ましい。それにより永久磁石の異方性磁場（保磁力）が10 kOe（≒796 kA/m）以上となり、最大エネルギー積が20 MGOe（≒159 kJ/m3）以上となる。規則度0.05未満では、永久磁石の保磁力が10 kOe未満となり、熱減磁し易くなる。 As a result of various studies by the present inventors, it is preferable to set the degree of order in the range of 0.05 or more and 1.0 or less. As a result, the anisotropic magnetic field (coercive force) of the permanent magnet becomes 10 kOe (≒ 796 kA / m) or more, and the maximum energy product becomes 20 MGOe (≒ 159 kJ / m 3 ) or more. If the degree of order is less than 0.05, the coercivity of the permanent magnet will be less than 10 kOe, making it easy to carry out thermal demagnetization.
　FeNi合金にC原子および／またはN原子を浸入させることにより、FeNi規則相を構成するFeNi結晶格子が膨張する。例えば、単位格子体積は0.5～10％膨張する。単位格子体積は、XRD測定によるFeNi相の面間隔から算出することができる。 By causing C atoms and / or N atoms to enter the FeNi alloy, the FeNi crystal lattice constituting the FeNi ordered phase expands. For example, the unit cell volume expands by 0.5 to 10%. The unit cell volume can be calculated from the spacing of the FeNi phase by XRD measurement.
　FeNi合金へのC原子やN原子の浸入は、例えば、アセチレンガスやアミンガスの分解によって生じる原子を永久磁石の内部に拡散させることによって成すことができる。C原子やN原子が浸入したFeNi合金永久磁石は、巨視的には、永久磁石の表面と内部との間でC原子やN原子の濃度差が生じる。また、微視的には、永久磁石の内部に存在するオーステナイト相の結晶粒内と粒界（結晶粒表面）との間でC原子やN原子の濃度差が生じる。すなわち、巨視的な永久磁石の表面と内部、および／または微視的な結晶粒の表面（粒界）と内部とでは、C原子やN原子の濃度差が生じ、深さ方向にC原子やN原子の濃度が低下する濃度勾配が認められるようになる。 The penetration of C atoms and N atoms into the FeNi alloy can be achieved, for example, by diffusing atoms generated by the decomposition of acetylene gas and amine gas into the interior of the permanent magnet. Macroscopically, in the FeNi alloy permanent magnet into which C atoms and N atoms have entered, a concentration difference of C atoms and N atoms occurs between the surface and the inside of the permanent magnet. Also, microscopically, a difference in concentration of C atoms and N atoms occurs between the grain boundaries of the austenite phase present inside the permanent magnet and the grain boundaries (grain surfaces). That is, there is a concentration difference between C atoms and N atoms between the surface and the inside of the macroscopic permanent magnet and / or the surface (grain boundaries) and the inside of the microscopic crystal grains, and the C atoms and A concentration gradient in which the concentration of N atoms decreases is observed.
　以下、実施例により本発明の具体例をより詳細に説明する。 Hereinafter, specific examples of the present invention will be described in more detail by way of examples.
　［実施例１］
　実施例１は、Fe-25重量％Ni合金を用いた永久磁石の一例である。 Example 1
Example 1 is an example of a permanent magnet using an Fe-25 wt% Ni alloy.
　別途用意したFe-25重量％Ni合金母材に対し、加工率50％で圧延加工して厚さ1 mmの板材とする。次に、このFe-25重量％Ni合金板の表面にFe3C粉末（粒径15μm以下）を厚さ100μmで塗布し、アルゴン（Ar）ガス雰囲気中において1000℃に加熱する。1000℃で100分間保持した後、Arガス雰囲気中で急冷する。 A separately prepared Fe-25 wt% Ni alloy base material is rolled at a working ratio of 50% to obtain a plate of 1 mm thickness. Next, an Fe 3 C powder (particle size 15 μm or less) is applied to a surface of the Fe-25 wt% Ni alloy plate to a thickness of 100 μm, and heated to 1000 ° C. in an argon (Ar) gas atmosphere. After holding at 1000 ° C. for 100 minutes, quenching is performed in an Ar gas atmosphere.
　Fe-25重量％Ni合金は、1000℃でオーステナイト相（γ相）となる。この熱処理中にFe3C粉末からC成分がγ相に拡散浸透し、γ相中にC成分が固溶する（例えば、1重量％固溶する）。昇温保持後に急冷することにより、冷却過程でフェライト相（α相）に変態せず、γ相が単相として得られる。このγ相は、C成分を1重量％含有する準安定相である。 The Fe-25 wt% Ni alloy becomes an austenitic phase (γ phase) at 1000 ° C. During this heat treatment, the C component diffuses into the γ phase from the Fe 3 C powder, and the C component forms a solid solution in the γ phase (for example, 1 wt% solid solution). By rapid cooling after temperature elevation holding, it does not transform to the ferrite phase (α phase) in the cooling process, and the γ phase is obtained as a single phase. This γ phase is a metastable phase containing 1% by weight of the C component.
　なお、拡散浸透工程における加熱温度および／または保持時間を調整することにより、固溶させる炭素量を調整することができる。 In addition, the amount of carbon to be dissolved can be adjusted by adjusting the heating temperature and / or the holding time in the diffusion and infiltration process.
　次に、C成分が固溶した板材を焼戻し（100℃で2時間保持）すると、FeNi規則相が生成・成長する。得られた試料をＸ線回折測定すると、FeNi規則相の生成・成長を示す回折ピークを確認することができる。 Next, when the plate material in which the C component is dissolved is tempered (held at 100 ° C. for 2 hours), the FeNi ordered phase is formed and grown. When X-ray diffraction measurement is performed on the obtained sample, a diffraction peak indicating the formation and growth of the FeNi ordered phase can be confirmed.
　拡散浸透工程において、炭素はオーステナイト相結晶に対して粒内拡散（バルク拡散とも言う）および粒界拡散する。拡散速度は、通常、粒界拡散の方が大きいことから、粒界拡散が先行した後、粒内拡散が進行する。そのため、粒界の炭素濃度は粒内の炭素濃度よりも高くなる。例えば、粒界の炭素濃度は、粒内の炭素濃度に比較して1.5～20倍に達する。 In the diffusion and infiltration process, carbon diffuses intragranularly (also referred to as bulk diffusion) and grain boundaries into austenite phase crystals. Since the diffusion rate is generally higher at grain boundary diffusion, intragranular diffusion proceeds after grain boundary diffusion precedes. Therefore, the carbon concentration in grain boundaries is higher than the carbon concentration in grains. For example, the carbon concentration at grain boundaries reaches 1.5 to 20 times as much as the carbon concentration in grains.
　粒界と粒内との炭素濃度の差異は、冷却時の微細組織に影響する。粒界では炭素濃度が高いため、冷却過程において粒界付近（粒界領域）で高炭素濃度のマルテンサイト相（α’相）が形成される。このため、焼戻し工程におけるFeNi規則相の生成・成長において、粒界付近のFeNi規則相の炭素濃度と粒内のFeNi規則相の炭素濃度とは差異が生じる。 The difference in carbon concentration between grain boundaries and intragrains affects the microstructure during cooling. Since the carbon concentration is high at grain boundaries, a martensitic phase (α ′ phase) of high carbon concentration is formed in the vicinity of grain boundaries (grain boundary region) in the cooling process. For this reason, in the formation and growth of the FeNi ordered phase in the tempering step, a difference occurs between the carbon concentration of the FeNi ordered phase near the grain boundaries and the carbon concentration of the FeNi ordered phase in the grains.
　また、Fe原子およびNi原子の原子拡散（再配列）はC原子やN原子の浸入により加速されることから、C濃度が高い粒界付近のFeNi規則相の規則度は、粒内のFeNi規則相の規則度よりも高くなる。 In addition, since the atomic diffusion (rearrangement) of Fe atoms and Ni atoms is accelerated by the infiltration of C atoms and N atoms, the degree of order of the FeNi ordered phase near the grain boundaries with high C concentration is the FeNi order in the grains. Higher than the regularity of the phase.
　なお、焼戻し工程における加熱温度および／または保持時間を調整することにより、規則度を調整することができる。 The degree of order can be adjusted by adjusting the heating temperature and / or the holding time in the tempering step.
　図１は、規則度と異方性磁場との関係を示すグラフの一例である。前述したように、規則度とは、XRD測定によるFeNi相の(0 0 1)面のピーク強度から算出される値であり、FeNi規則相とFeNi不規則相との合計に対するFeNi規則相の割合を示すものである。例えば、規則度0.5未満は、FeNi不規則相がFeNi規則相よりも多いことを意味し、規則度0.5超は、FeNi規則相がFeNi不規則相よりも多いことを意味する。規則度1.0は、FeNi不規則相がない状態（全てFeNi規則相である状態）に相当する。 FIG. 1 is an example of a graph showing the relationship between the degree of order and the anisotropic magnetic field. As described above, the degree of order is a value calculated from the peak intensity of the (001) plane of the FeNi phase by XRD measurement, and the ratio of the FeNi ordered phase to the total of the FeNi ordered phase and the FeNi disordered phase Is an indicator of For example, a degree of order less than 0.5 means that the FeNi disordered phase is greater than the FeNi ordered phase, and a degree of order greater than 0.5 means that the FeNi ordered phase is greater than the FeNi disordered phase. The degree of order of 1.0 corresponds to the state in which there is no FeNi irregular phase (all in the state of being an FeNi ordered phase).
　図１は、C濃度が0.1重量％の試料およびC濃度が1.0重量％の試料を用いて、規則度と異方性磁場との関係を調べた結果である。図１に示したように、規則度が0.01未満の場合、0.1重量％Cの試料および1.0重量％Cの試料の両方において、異方性磁場が5 kOe以下である。永久磁石の異方性磁場が10 kOe未満であると熱減磁し易くなる。言い換えると、本発明では、永久磁石の異方性磁場として10 kOe以上を合格と判定する。 FIG. 1 shows the results of examining the relationship between the degree of order and the anisotropic magnetic field using a sample having a C concentration of 0.1 wt% and a sample having a C concentration of 1.0 wt%. As shown in FIG. 1, when the degree of order is less than 0.01, the anisotropic magnetic field is 5 kOe or less in both the 0.1 wt% C sample and the 1.0 wt% C sample. If the anisotropic magnetic field of the permanent magnet is less than 10 kOe, heat demagnetization is likely to occur. In other words, in the present invention, 10 kOe or more is determined as a pass as the anisotropic magnetic field of the permanent magnet.
　規則度が0.05になると、0.1重量％Cの試料および1.0重量％Cの試料の両方において、異方性磁場が10 kOeに達する。規則度が大きくなるほど、異方性磁場も大きくなる傾向があり、本実施形態において好ましい規則度の範囲は0.05以上であることが分かった。 When the degree of order is 0.05, the anisotropic magnetic field reaches 10 kOe in both the 0.1 wt% C sample and the 1.0 wt% C sample. As the degree of order increases, the anisotropic magnetic field also tends to increase, and it has been found that the range of the degree of order preferred in the present embodiment is 0.05 or more.
　なお、図１には示していないが、規則度が0.3超の場合も、C濃度が0.1重量％の試料および1.0重量％Cの試料の両方において、異方性磁場が10 kOe以上となることを確認している。 Although not shown in FIG. 1, the anisotropic magnetic field should be 10 kOe or more in both the sample with a C concentration of 0.1 wt% and the sample with a 1.0 wt% C even when the degree of order exceeds 0.3. Have confirmed.
　ここで、1.0重量％Cで規則度0.05の試料は、異方性磁場が30 kOeであり、保磁力が10～15 kOe、最大エネルギー積が20～21 MGOeとなる。これは、炭素濃度が高いFeNi規則相では、侵入炭素による結晶格子の歪により、fcc（面心立方晶）構造からbct（体心正方晶）構造になったためと考えられる。 Here, a sample with a 1.0 wt% C and an order of 0.05 has an anisotropic magnetic field of 30 kOe, a coercive force of 10 to 15 kOe, and a maximum energy product of 20 to 21 MGOe. It is considered that this is because in the FeNi ordered phase having a high carbon concentration, the fcc (face-centered cubic) structure changes to a bct (body-centered tetragonal) structure due to distortion of the crystal lattice due to interstitial carbon.
　図２は、C濃度と保磁力との関係を示すグラフの一例である。これは、実施例１の拡散浸透工程および焼戻し工程の条件を調整することによってC濃度を調整して、得られた永久磁石の保磁力を調べたものである。 FIG. 2 is an example of a graph showing the relationship between C concentration and coercivity. This is the result of examining the coercivity of the obtained permanent magnet by adjusting the C concentration by adjusting the conditions of the diffusion / infiltration step and the tempering step of Example 1.
　図２に示したように、0.1重量％Cの試料における保磁力は0.3 kOeである。0.5重量％Cの試料における保磁力は0.5 kOeである。1.2重量％CまではC濃度の増加に伴って保磁力が増加し、1.2重量％Cを超えると保磁力が低下している。言い換えると、0.5～2重量％Cの範囲において、0.5重量％C未満の場合よりも保磁力が増加していると言える。特に1～1.5重量％Cの範囲が好ましく、5 kOe以上の保磁力が確認できる。この場合、最大エネルギー積は20 MGOe以上となる。 As shown in FIG. 2, the coercivity of the 0.1 wt% C sample is 0.3 kOe. The coercivity of the 0.5 wt% C sample is 0.5 kOe. The coercivity increases as the C concentration increases up to 1.2 wt% C, and the coercivity decreases as it exceeds 1.2 wt% C. In other words, it can be said that the coercive force is increased in the range of 0.5 to 2% by weight C as compared with the case of less than 0.5% by weight C. The range of 1 to 1.5 wt% C is particularly preferable, and a coercive force of 5 kOe or more can be confirmed. In this case, the maximum energy product is 20 MGOe or more.
　図３は、本発明の永久磁石の断面の微細組織の一例を示す模式図である。図３に示したように、本発明の永久磁石は、多数の結晶粒1が結晶粒界（粒界と略す）2を介して接する微細組織を有している。粒界2のC濃度は結晶粒1内部のC濃度の1.5～20倍となり、粒界2から結晶粒1内部へ厚さ100 nm以内の領域（粒界領域と称す）におけるFeNi規則度が結晶粒1内部のFeNi期則度よりも高くなっている。粒界領域のFeNi規則度が高いため、結晶磁気異方性エネルギーが大きくなり、高い保磁力を発現することができる。 FIG. 3 is a schematic view showing an example of the microstructure of the cross section of the permanent magnet of the present invention. As shown in FIG. 3, the permanent magnet of the present invention has a microstructure in which a large number of crystal grains 1 are in contact via grain boundaries (abbreviated as grain boundaries) 2. The C concentration in grain boundary 2 is 1.5 to 20 times the C concentration in crystal grain 1 and the FeNi order in the region (referred to as grain boundary region) within 100 nm thickness from grain boundary 2 to crystal grain 1 is the crystal It is higher than the FeNi periodicity inside grain 1. Since the FeNi order in the grain boundary region is high, the magnetocrystalline anisotropy energy becomes large, and high coercivity can be expressed.
　実施例１の比較材として、始めから炭素を1重量％含有させたFe-25重量％Ni-1重量％C合金母材を用いる代わりに、Fe3C粉末塗布を行わない試料を用意した。具体的には、Fe-25重量％Ni-1重量％C合金母材に対し、加工率50％で圧延加工して厚さ1 mmの板材とする。次に、1000℃に加熱して2時間保持した後、Arガス雰囲気中で急冷する。 As a comparative material of Example 1, instead of using an Fe-25 wt% Ni-1 wt% C alloy base material containing 1 wt% of carbon from the beginning, a sample not subjected to Fe 3 C powder coating was prepared. Specifically, a rolling process is carried out at a working ratio of 50% with respect to an Fe-25 wt% Ni-1 wt% C alloy base material to obtain a plate having a thickness of 1 mm. Next, after heating to 1000 ° C. and holding for 2 hours, quenching is performed in an Ar gas atmosphere.
　Fe-25重量％Ni-1重量％C合金は、1000℃でオーステナイト相となり、急冷によりマルテンサイト相となる。その後、該板材を100℃で焼戻しを行って、FeNi規則相を生成・成長させる。 The Fe-25 wt% Ni-1 wt% C alloy becomes an austenitic phase at 1000 ° C. and becomes a martensitic phase upon quenching. Thereafter, the plate material is tempered at 100 ° C. to form and grow an FeNi ordered phase.
　得られた比較試料に対して、先と同様の調査を行った。その結果、粒界領域と粒内との間でFeNi相の規則度に有意差は認められない。規則度は0.01であり、保磁力が1 kOe、最大エネルギー積が4 MGOeであった。 The same examination as described above was performed on the obtained comparative samples. As a result, no significant difference is observed in the order of FeNi phase between the grain boundary region and the intragranular region. The degree of order was 0.01, the coercivity was 1 kOe, and the maximum energy product was 4 MGOe.
　合金母材の段階でC成分を固溶させた場合、C成分は合金母材の内部でほぼ均等に分布するため、結晶粒内部と粒界との間でC濃度の差異は生じない。その結果、結晶粒内部と粒界とで規則度がほぼ同じとなり、大きな結晶磁気異方性エネルギーを得ることができない。それ故、保磁力および最大エネルギー積が向上しなかったと考えられる。 When the C component is solid-solved at the stage of the alloy base material, the C component is distributed substantially equally in the inside of the alloy base material, so that there is no difference in C concentration between the inside of the crystal grain and the grain boundary. As a result, the degree of order becomes almost the same in the interior of the crystal grain and the grain boundary, and a large magnetocrystalline anisotropy energy can not be obtained. Therefore, it is considered that the coercivity and the maximum energy product did not improve.
　［実施例２］
　実施例２は、合金母材のNi濃度が永久磁石の異方性磁場に与える影響を調査した例である。 Example 2
Example 2 is an example in which the influence of the Ni concentration of the alloy base material on the anisotropic magnetic field of the permanent magnet was investigated.
　合金母材のNi濃度を調整した以外は実施例１と同様にして、1.0重量％Cの試料を用意した。図４は、Ni濃度と異方性磁場との関係を示すグラフの一例である。図４に示したように、Ni濃度が25～55重量％の範囲において、異方性磁場が15kOe以上となり強い磁気異方性が得られることが確認できる。この場合、最大エネルギー積は21 MGOe以上となる。 A 1.0 wt% C sample was prepared in the same manner as in Example 1 except that the Ni concentration of the alloy base material was adjusted. FIG. 4 is an example of a graph showing the relationship between the Ni concentration and the anisotropic magnetic field. As shown in FIG. 4, when the Ni concentration is in the range of 25 to 55% by weight, it can be confirmed that the anisotropic magnetic field is 15 kOe or more and strong magnetic anisotropy can be obtained. In this case, the maximum energy product is 21 MGOe or more.
　［実施例３］
　実施例３では、Fe-30重量％Ni合金を用いた永久磁石用粉末および該粉末を用いた永久磁石の一例を説明する。 [Example 3]
Example 3 describes an example of a powder for a permanent magnet using an Fe-30 wt% Ni alloy and a permanent magnet using the powder.
　別途用意したFe-30重量％Ni合金母材に対し、加工率50％で圧延加工して厚さ1 mmの板材とする。次に、このFe-30重量％Ni合金板の表面にFe3C粉末（粒径15μm以下）を厚さ100μmで塗布し、Arガス雰囲気中において1000℃に加熱する。Fe3C粉末の粒径は15μm以下である。塗布厚さは100μmである。1000℃で100分間保持した後、Arガス雰囲気中で急冷する。急冷の冷却速度は20～50℃/秒である。Arガス雰囲気中の冷却により材料の酸化が防止でき、合金結晶の粒界での酸素濃度を100 ppm以下にすることができる。これによりC成分の拡散が促進される。 A separately prepared Fe-30% by weight Ni alloy base material is rolled at a working ratio of 50% to obtain a plate having a thickness of 1 mm. Next, Fe 3 C powder (particle size 15 μm or less) is applied to a surface of the Fe-30 wt% Ni alloy plate with a thickness of 100 μm, and heated to 1000 ° C. in an Ar gas atmosphere. The particle size of the Fe 3 C powder is 15 μm or less. The coating thickness is 100 μm. After holding at 1000 ° C. for 100 minutes, quenching is performed in an Ar gas atmosphere. The cooling rate of the quenching is 20 to 50 ° C./second. Oxidation in the material can be prevented by cooling in an Ar gas atmosphere, and the oxygen concentration at the grain boundary of the alloy crystal can be made 100 ppm or less. This promotes the diffusion of the C component.
　Fe-30重量％Ni合金は、1000℃でオーステナイト相単相となる。この熱処理中にFe3C粉末からC成分がγ相に拡散浸透し、γ相中にC成分が固溶する。昇温保持後に急冷することにより、冷却過程でα相に変態せず、γ相が単相として得られる。急冷した板材は、結晶粒界のC濃度が結晶粒内部のC濃度よりも高く、粒界が粒内よりも機械的に脆い状態になっている。そこで、急冷した板材を粉砕すると、粒径5～10μmの粉末が得られる。 The Fe-30 wt% Ni alloy becomes an austenitic single phase at 1000 ° C. During this heat treatment, the C component diffuses into the γ phase from the Fe 3 C powder, and the C component dissolves in the γ phase. By rapid cooling after temperature rising and holding, it is not transformed into the α phase in the cooling process, and the γ phase is obtained as a single phase. In the rapidly cooled plate material, the C concentration in the grain boundary is higher than the C concentration in the grain, and the grain boundary is mechanically more brittle than the grain. Then, when the rapidly cooled plate material is crushed, a powder having a particle diameter of 5 to 10 μm is obtained.
　次に、当該粉末に対して焼戻し工程（200℃で10時間保持した後、冷却）を行うことにより、永久磁石用粉末を得る。 Next, the powder is subjected to a tempering step (after being kept at 200 ° C. for 10 hours, and then cooling) to obtain a powder for permanent magnet.
　当該焼戻し工程を磁場中（例えば、20 kOe中）で行うことはより好ましい。磁場中の焼戻しにより、Fe、NiおよびCの各原子は、磁場方向に磁化が最大となるように再配列し、粉末の容易磁化方向が磁場方向に平行となる。このため最大エネルギー積を増加させることが可能である。 It is more preferable to carry out the tempering step in a magnetic field (for example, in 20 kOe). By tempering in a magnetic field, each atom of Fe, Ni and C rearranges in the direction of the magnetic field so as to maximize the magnetization, and the easy magnetization direction of the powder becomes parallel to the direction of the magnetic field. It is thus possible to increase the maximum energy product.
　得られた永久磁石用粉末の特徴を次に説明する。粉末粒子の表面は、粒子内部よりもC濃度が高く1.5～2重量％である。該C濃度の分布は、0.01～1重量％C μm-1の濃度勾配で表面から内部にかけて減少する分布をもつ。粉末粒子の表面近傍の規則度は、粒子内部の平均の規則度よりも高い。粉末粒子の結晶構造は、fcc、bctまたはこれらの混相である。キュリー点は540℃であり、FeNi規則相の分解温度はこの温度以下である。 The characteristics of the obtained permanent magnet powder will be described below. The surface of the powder particle has a C concentration higher than that of the inside of the particle and is 1.5 to 2% by weight. The C concentration distribution has a decreasing distribution from the surface to the inside with a concentration gradient of 0.01 to 1 wt% C μm −1 . The degree of order near the surface of the powder particles is higher than the average degree of order inside the particles. The crystal structure of the powder particles is fcc, bct or mixed phases thereof. The Curie point is 540 ° C., and the decomposition temperature of the FeNi ordered phase is below this temperature.
　上記粉末を用いて、該粉末を磁場中（例えば、10 kOe中）で配向させた後に10 t/cm2の圧力で加圧して成形体を形成する。次に、成形体に対して、1.0 Tの磁場中で250℃に加熱して10時間保持した後、該磁場中で徐冷（例えば、1℃/min以下で冷却）して永久磁石を作製する。印加した磁場方向は、粉末の配向磁場方向と平行である。 Using the above powder, the powder is oriented in a magnetic field (for example, in 10 kOe) and then pressurized at a pressure of 10 t / cm 2 to form a compact. Next, the molded body is heated to 250 ° C. in a magnetic field of 1.0 T and held for 10 hours, and then slowly cooled (for example, cooled at 1 ° C./min or less) in the magnetic field to produce a permanent magnet. Do. The applied magnetic field direction is parallel to the orientation magnetic field direction of the powder.
　得られた永久磁石の20℃における磁気特性は、残留磁束密度1.2 T、保磁力9 kOe、最大エネルギー積22 MGOeである。 The magnetic properties of the obtained permanent magnet at 20 ° C. are a residual magnetic flux density of 1.2 T, a coercive force of 9 kOe, and a maximum energy product of 22 MGOe.
　［実施例４］
　実施例４は、実施例１で用いたFe3C粉末の代わりにFe4N粉末を用いた永久磁石の一例である。 Example 4
Example 4 is an example of a permanent magnet using Fe 4 N powder instead of the Fe 3 C powder used in Example 1.
　実施例１と同じFe-25重量％Ni合金母材に対し、加工率50％で圧延加工して厚さ0.5 mmの板材とする。次に、このFe-25重量％Ni合金板の表面にFe4N粉末（粒径15μm以下）を厚さ100μmで塗布し、Arガス雰囲気中において900℃に加熱する。900℃で100分間保持した後、Arガス雰囲気中で急冷する。 The same Fe-25% by weight Ni alloy base material as in Example 1 is rolled at a working ratio of 50% to obtain a plate having a thickness of 0.5 mm. Next, an Fe 4 N powder (particle size of 15 μm or less) is applied to a surface of the Fe-25 wt% Ni alloy plate to a thickness of 100 μm, and heated to 900 ° C. in an Ar gas atmosphere. After holding at 900 ° C. for 100 minutes, quenching is performed in an Ar gas atmosphere.
　Fe-25重量％Ni合金は、900℃でオーステナイト単相となる。この熱処理中にFe4N粉末からN成分がγ相に拡散浸透し、γ相中にN成分が固溶する（例えば、0.8重量％固溶する）。昇温保持後に急冷することにより、冷却過程でα相に変態せず、γ相が単相として得られる。このγ相は、N成分を0.8重量％含有する準安定相である。 The Fe-25 wt% Ni alloy becomes austenite single phase at 900 ° C. During this heat treatment, the N component diffuses into the γ phase from the Fe 4 N powder, and the N component forms a solid solution in the γ phase (for example, 0.8 wt% solid solution). By rapid cooling after temperature rising and holding, it is not transformed into the α phase in the cooling process, and the γ phase is obtained as a single phase. This γ phase is a metastable phase containing 0.8% by weight of the N component.
　なお、拡散浸透工程における加熱温度および／または保持時間を調整することにより、固溶させる窒素量を調整することができる。 In addition, the amount of nitrogen to be dissolved can be adjusted by adjusting the heating temperature and / or the holding time in the diffusion and infiltration process.
　次に、N成分が固溶した板材を焼戻し（100℃で2時間保持）すると、FeNi規則相が生成・成長する。得られた試料をXRD測定すると、FeNi規則相の生成・成長を示す回折ピークを確認することができる。 Next, when the plate material in which the N component is dissolved is tempered (held at 100 ° C. for 2 hours), the FeNi ordered phase is formed and grown. By XRD measurement of the obtained sample, it is possible to confirm a diffraction peak indicating the formation and growth of the FeNi ordered phase.
　拡散浸透工程において、窒素はオーステナイト相結晶に対して粒内拡散および粒界拡散する。拡散速度は、粒界拡散の方が大きいことから、粒界拡散が先行した後、粒内拡散が進行する。そのため、粒界は粒内よりも窒素濃度が高くなる。例えば、粒界の窒素濃度は、粒内の窒素濃度に比較して1.5～20倍に達する。 In the diffusion and infiltration process, nitrogen diffuses into the austenite phase crystals and diffuses at grain boundaries. Since the diffusion speed is higher at grain boundary diffusion, intragranular diffusion proceeds after grain boundary diffusion precedes. Therefore, the grain boundary has a nitrogen concentration higher than that in the grain. For example, the concentration of nitrogen at grain boundaries reaches 1.5 to 20 times the concentration of nitrogen in grains.
　粒界と粒内との窒素濃度の差異は、冷却時の微細組織に影響する。粒界では窒素濃度が高いため、冷却過程において粒界付近で高窒素濃度のマルテンサイト相が形成される。このため、焼戻し工程におけるFeNi規則相の生成・成長において、粒界付近のFeNi規則相の窒素濃度と粒内のFeNi規則相の窒素濃度とは差異が生じる。 The difference in nitrogen concentration between grain boundaries and intragrains affects the microstructure during cooling. Since the nitrogen concentration is high at grain boundaries, a martensitic phase of high nitrogen concentration is formed in the vicinity of grain boundaries in the cooling process. For this reason, in the formation and growth of the FeNi ordered phase in the tempering step, a difference occurs between the nitrogen concentration of the FeNi ordered phase near the grain boundaries and the nitrogen concentration of the FeNi ordered phase in the grains.
　前述したように、Fe原子およびNi原子の原子拡散はC原子やN原子の浸入により加速されることから、N濃度が高い粒界付近のFeNi規則相の規則度は、粒内のFeNi規則相の規則度よりも高くなる。 As described above, since atomic diffusion of Fe atoms and Ni atoms is accelerated by the penetration of C atoms and N atoms, the degree of order of the FeNi ordered phase near the grain boundary where the N concentration is high is the FeNi ordered phase within the grains. Higher than the regularity of.
　なお、焼戻し工程における加熱温度および／または保持時間を調整することにより、規則度を調整することができる。 The degree of order can be adjusted by adjusting the heating temperature and / or the holding time in the tempering step.
　例えば、0.8重量％Nで規則度0.05の試料は、25 kOeの異方性磁場を示す。これは、窒素濃度が高いFeNi規則相では、侵入窒素による結晶格子の歪により、fcc構造からbct構造になったためと考えられる。 For example, a sample with 0.8 wt% N and a regularity of 0.05 exhibits an anisotropic magnetic field of 25 kOe. This is considered to be because in the FeNi ordered phase having a high nitrogen concentration, the fcc structure is changed to the bct structure due to the strain of the crystal lattice due to interstitial nitrogen.
　0.8重量％Nで規則度0.05の板材試料に対して、1.0 Tの磁場中で250℃に加熱して10時間保持した後、該磁場中で徐冷して永久磁石を作製する。該永久磁石の最大エネルギー積を評価した結果、21 MGOeであった。また、キュリー点は570℃であった。 After heating at 250 ° C. in a magnetic field of 1.0 T and holding for 10 hours with respect to a plate material sample of 0.8 wt% N and regularity 0.05, the permanent magnet is manufactured by slow cooling in the magnetic field. As a result of evaluating the maximum energy product of the permanent magnet, it was 21 MGOe. Moreover, the Curie point was 570 ° C.
　図５は、N濃度と保磁力との関係を示すグラフの一例である。これは、拡散浸透工程および焼戻し工程の条件を調整することによってN濃度を調整して、得られた永久磁石の保磁力を調べたものである。 FIG. 5 is an example of a graph showing the relationship between the N concentration and the coercivity. This is the result of examining the coercivity of the obtained permanent magnet by adjusting the N concentration by adjusting the conditions of the diffusion / infiltration step and the tempering step.
　図５に示したように、1.5重量％NまではN濃度の増加に伴って保磁力が増加し、1.5重量％Nを超えると保磁力が低下している。言い換えると、0.4～2重量％Nの範囲において、0.4重量％N未満の場合よりも保磁力が増大していると言える。1～2重量％Nの範囲が好ましく、保磁力が5 kOe以上となる。また、1.2～1.5重量％Nの範囲がより好ましく、保磁力が10 kOe以上となる。1.2～1.5重量％Nの範囲の場合、最大エネルギー積は20～25 MGOeとなる。 As shown in FIG. 5, the coercivity increases as the N concentration increases up to 1.5 wt% N, and the coercivity decreases as it exceeds 1.5 wt% N. In other words, it can be said that the coercive force is increased in the range of 0.4 to 2% by weight N more than the case of less than 0.4% by weight N. The range of 1 to 2 wt% N is preferable, and the coercivity is 5 kOe or more. Further, the range of 1.2 to 1.5 wt% N is more preferable, and the coercive force is 10 kOe or more. In the range of 1.2 to 1.5 wt% N, the maximum energy product is 20 to 25 MGOe.
　1重量％Nで規則度0.05の板材試料に対して、上記と同様の着磁工程を行って、永久磁石を作製する。該永久磁石の最大エネルギー積を評価した結果、10 MGOeであった。また、キュリー点は540℃であった。 The same magnetizing step as described above is performed on a plate material sample having 1% by weight N and a regularity of 0.05 to produce a permanent magnet. As a result of evaluating the maximum energy product of the permanent magnet, it was 10 MGOe. Moreover, the Curie point was 540 degreeC.
　FeNiN系永久磁石のキュリー点がネオジム永久磁石のキュリー点（310℃）よりもかなり高いことから、FeNiN系永久磁石は耐熱性が高いと言える。 Since the Curie point of the FeNiN permanent magnet is considerably higher than the Curie point (310 ° C.) of the neodymium permanent magnet, it can be said that the FeNiN permanent magnet has high heat resistance.
　実施例４の比較材として、始めから窒素を1重量％含有させたFe-25重量％Ni-1重量％N合金母材を用いる代わりに、Fe4N粉末塗布を行わない試料を用意した。具体的には、Fe-25重量％Ni-1重量％N合金母材に対し、加工率50％で圧延加工して厚さ1 mmの板材とする。次に、900℃に加熱して2時間保持した後、Arガス雰囲気中で急冷する。 As a comparative material of Example 4, a sample without Fe 4 N powder coating was prepared instead of using an Fe-25 wt% Ni-1 wt% N alloy base material containing 1 wt% nitrogen from the beginning. Specifically, rolling is performed at a working ratio of 50% with respect to an Fe-25 wt% Ni-1 wt% N alloy base material to obtain a plate having a thickness of 1 mm. Next, after heating to 900 ° C. and holding for 2 hours, quenching is performed in an Ar gas atmosphere.
　Fe-25重量％Ni-1重量％N合金は、900℃でオーステナイト相となり、急冷によりマルテンサイト相となる。その後、該板材を100℃で焼戻しを行って、FeNi規則相を生成・成長さらる。 The Fe-25 wt% Ni-1 wt% N alloy becomes an austenitic phase at 900 ° C. and a martensitic phase upon quenching. Thereafter, the plate material is tempered at 100 ° C. to form and grow an FeNi ordered phase.
　得られた比較試料に対して、先と同様の調査を行った。その結果、しかし比較例では粒界領域と粒内との間でFeNi相の規則度に有意差は認められない。規則度は0.01であり、保磁力が1.5 kOe、最大エネルギー積が5 MGOeであった。 The same examination as described above was performed on the obtained comparative samples. As a result, however, in the comparative example, no significant difference is observed in the order of the FeNi phase between the grain boundary region and the intragranular region. The degree of order was 0.01, the coercivity was 1.5 kOe, and the maximum energy product was 5 MGOe.
　合金母材の段階でN成分を固溶させた場合、N成分は合金母材の内部でほぼ均等に分布するため、結晶粒内部と粒界との間でN濃度の差異は生じない。言い換えると、N成分が粒界に偏在しない。全体的にN濃度が希薄であることから、N原子の浸入によるFe原子およびNi原子の原子拡散（再配列）の駆動力も小さくなり、保磁力および最大エネルギー積が向上しなかったと考えられる。 When the N component is solid-solved at the stage of the alloy base material, the N component is distributed substantially equally in the inside of the alloy base material, so that there is no difference in N concentration between the inside of the crystal grains and the grain boundaries. In other words, the N component is not localized at grain boundaries. It is considered that the driving force of atomic diffusion (rearrangement) of Fe atoms and Ni atoms due to the penetration of N atoms is also reduced, and the coercivity and the maximum energy product have not been improved, since the overall N concentration is low.
　［実施例５］
　実施例５では、規則度と保磁力との関係について考察する。 [Example 5]
In the fifth embodiment, the relationship between the degree of order and the coercivity is considered.
　まず、本発明において、粒界とは、隣り合う結晶粒間での結晶方位の角度差が15度以上である境界と定義する。この境界（粒界）から厚さ0.1μm以内の範囲にある結晶格子は粒界の影響を受け易い。そこで、粒界から結晶粒中心部側に厚さ0.1μｍ以内の領域を粒界領域と定義する。 First, in the present invention, a grain boundary is defined as a boundary in which the difference in crystal orientation between adjacent crystal grains is 15 degrees or more. The crystal lattice in the range of 0.1 μm or less in thickness from this boundary (grain boundary) is susceptible to the grain boundary. Therefore, a region having a thickness of 0.1 μm or less from the grain boundary to the crystal grain center side is defined as a grain boundary region.
　前述したように、炭素や窒素などの侵入型元素を多結晶体中に拡散浸透させる場合、多結晶体の結晶粒内と結晶粒界とでは拡散速度が異なり、粒界拡散の方が粒内拡散よりも拡散速度が速い（すなわち、拡散量が多くなる）。粒界上で拡散元素の濃度が高くなると、粒界上と粒内との間で濃度勾配が生じるため、粒界領域で拡散元素濃度が容易に上昇する。すると、粒界領域と粒内（粒界から厚さ0.1μm超の領域）との間で拡散元素濃度に差異が生じる。 As described above, when the interstitial element such as carbon or nitrogen is diffused and infiltrated into the polycrystal, the diffusion speed is different between the crystal grain and the grain boundary of the polycrystal, and the grain boundary diffusion is the inside of the grain. Diffusion rate is faster than diffusion (ie, the amount of diffusion is increased). When the concentration of the diffusion element on the grain boundary becomes high, a concentration gradient is generated between the grain boundary and the inside of the grain, so that the concentration of the diffusion element easily rises in the grain boundary region. Then, a difference occurs in the diffusion element concentration between the grain boundary region and the inside of the grain (the region from the grain boundary to a thickness of more than 0.1 μm).
　拡散元素濃度の差異は、結晶格子の歪差を意味し、結晶格子を構成する原子の再配列の駆動力差につながる。その結果、規則相の生成・成長の差異（すなわち、規則度の差異）が生じる。規則度の差異は、電子顕微鏡の電子線回折像の解析から確認することができる。 The difference in the concentration of the diffusion element means the difference in strain of the crystal lattice, which leads to the difference in driving force of rearrangement of atoms constituting the crystal lattice. As a result, a difference in generation / growth of regular phases (that is, a difference in regularity) occurs. The difference in degree of order can be confirmed from the analysis of the electron beam diffraction image of the electron microscope.
　電子線回折像の規則構造を示す超格子回折点の強度あるいはFeNi不規則相に対応する回折点の強度比から換算される規則度は、粒界領域と粒内とで異なることが確認されている。具体的には、炭素や窒素などの侵入型元素を拡散浸透させると、粒界領域における規則相の(0 0 1)面の回折点の強度が粒内のそれよりも高くなり、粒界領域における規則相の(0 0 1)面の回折点の強度とFeNi不規則相の(1 1 1)面の回折点の強度との比が粒内のそれよりも高くなることが確認されている。 It is confirmed that the degree of order converted from the intensity ratio of the superlattice diffraction point showing the ordered structure of the electron beam diffraction image or the intensity ratio of the diffraction point corresponding to the FeNi disordered phase differs between the grain boundary region and the inside of the grain There is. Specifically, when an interstitial element such as carbon or nitrogen is diffused and permeated, the intensity of the diffraction point of the (001) plane of the ordered phase in the grain boundary region becomes higher than that in the grain, and the grain boundary region It has been confirmed that the ratio of the intensity of the diffraction point of the (001) plane of the ordered phase to that of the diffraction spot of the (1 1 1) plane of the FeNi disordered phase is higher than that in the grain. .
　図６は、Fe-25重量％Ni合金における粒界領域の規則度（以下、粒界規則度と称す）と保磁力との関係を示すグラフの一例である。図６に示すように、粒界規則度と保磁力とは強い相関関係にあり、粒界規則度が0.7以上であれば、20 kOe以上の保磁力を示すことがわかる。 FIG. 6 is an example of a graph showing the relationship between the degree of order (hereinafter referred to as the order of grain boundaries) and the coercivity of grain boundary regions in a Fe-25 wt% Ni alloy. As shown in FIG. 6, there is a strong correlation between the grain boundary order degree and the coercivity, and it is understood that when the grain boundary order degree is 0.7 or more, a coercivity of 20 kOe or more is exhibited.
　粒界規則度が0.9の試料では、粒内規則度が0.02であり、結晶粒全体としての平均規則度が0.05であったが、最大エネルギー積が40 MGOeであり、150℃における最大エネルギー積ではNdFeB系焼結永久磁石のそれ（35 MGOe）を超えることを確認している。すなわち、粒界規則度が高ければ、たとえ粒内規則度および平均規則度が低くても、良好な磁石特性が得られる。 In the sample with the grain boundary order degree of 0.9, the intragranular order degree is 0.02 and the average order degree of the whole crystal grain is 0.05, but the maximum energy product is 40 MGOe, and the maximum energy product at 150 ° C. It has been confirmed to exceed that of an NdFeB-based sintered permanent magnet (35 MGOe). That is, if the grain boundary order is high, good magnetic properties can be obtained even if the intragranular order and the average order are low.
　以上説明したように、本発明の永久磁石は、FeNi系合金における粒界規則度が粒内規則度よりも10倍以上高く、粒界領域での結晶磁気異方性が高くなっている。言い換えると、粒界領域での結晶磁気異方性を高めることにより、保磁力や最大エネルギー積などの永久磁石の性能高められることが分かる。 As described above, in the permanent magnet of the present invention, the grain boundary order degree in the FeNi-based alloy is 10 times or more higher than the intra-grain order degree, and the crystal magnetic anisotropy in the grain boundary region is high. In other words, it is understood that the performance of the permanent magnet such as the coercivity and the maximum energy product can be enhanced by enhancing the magnetocrystalline anisotropy in the grain boundary region.
　［実施例６］
　実施例６では、Fe-35重量％Ni合金に関し、コバルトを添加した永久磁石の一例を説明する。前述の実施例１～５では炭素や窒素の侵入型元素を添加した例を説明したが、コバルト添加でも同様の作用効果がある。これは、コバルト（Co）を添加することでFe-35重量％Ni合金の結晶磁気異方性が増加するためである。 [Example 6]
In Example 6, an example of a cobalt-added permanent magnet will be described with respect to an Fe-35 wt% Ni alloy. Although the examples in which the interstitial elements of carbon and nitrogen are added have been described in the above-described first to fifth embodiments, the same effect can be obtained by adding cobalt. This is because addition of cobalt (Co) increases the magnetocrystalline anisotropy of the Fe-35 wt% Ni alloy.
　別途用意したFe-35重量％Ni合金母材をArガス雰囲気中で高周波溶解し、合金溶湯を回転するロール（例えば、ロール回転速度3000 rpm）に噴射する単ロール液体急冷凝固法により、Fe-35重量％Ni合金粉末（例えば、長軸径約30μmの扁平粒子粉末）が得られる。扁平粒子のアスペクト比（長軸径/短軸長）は、2～10である。 A single roll liquid rapid solidification method in which a separately prepared Fe-35 wt% Ni alloy base material is high-frequency melted in an Ar gas atmosphere and the molten alloy is jetted onto a rotating roll (for example, a roll rotational speed of 3000 rpm) A 35 wt% Ni alloy powder (for example, flat particle powder with a major axis diameter of about 30 μm) is obtained. The aspect ratio (major axis diameter / minor axis length) of the flat particles is 2 to 10.
　この合金粉末とCo粉末（例えば、粒径10～50 nm）とを所定の重量比率（例えば、Fe-35重量％Ni合金粉末：Co粉末＝10：1）で混合して混合粉末を用意する。これにより、Fe-35重量％Ni合金粉末粒子の表面にCo粒子が付着する。 A mixed powder is prepared by mixing the alloy powder and a Co powder (for example, a particle size of 10 to 50 nm) at a predetermined weight ratio (for example, Fe-35 wt% Ni alloy powder: Co powder = 10: 1) . As a result, Co particles adhere to the surface of the Fe-35 wt% Ni alloy powder particles.
　次に、混合粉末を磁場中（例えば、10 kOeの静磁場中）で配向させた後に1 t/cm2の圧力で加圧して多孔質成形体（例えば、かさ密度3 g/cm3）を形成する。次に、1000℃に加熱して1時間保持した後、アセチレンガスを導入して30分間保持した後に急冷することにより、Co成分がFe-35重量％Ni合金結晶粒の表面から拡散浸透した焼結体が得られる。その後、実施例１と同様にして、C成分を更に拡散浸透させた永久磁石を作製する。 Next, the mixed powder is oriented in a magnetic field (for example, in a static magnetic field of 10 kOe) and then pressurized at a pressure of 1 t / cm 2 to obtain a porous molded body (for example, bulk density 3 g / cm 3 ) Form. Next, after heating to 1000 ° C. and holding for 1 hour, acetylene gas is introduced and held for 30 minutes, and then quenching is performed, whereby the Co component diffuses and permeates from the surface of the Fe-35 wt% Ni alloy crystal grain A body is obtained. Thereafter, in the same manner as in Example 1, a permanent magnet in which the C component is further diffused and permeated is manufactured.
　なお、拡散浸透工程における加熱温度および／または保持時間を調整することにより、拡散浸透させるCo量を調整することができる。 Note that the amount of Co to be diffused and infiltrated can be adjusted by adjusting the heating temperature and / or the holding time in the diffusion and infiltration step.
　作製した永久磁石の保磁力は11-20 kOeであった。図７は、Co濃度と最大エネルギー積との関係を示すグラフの一例である。図７に示したように、Co濃度が0.2～10重量％の範囲の試料において、最大エネルギー積はCo無添加の試料よりも増加することが分かる。 The coercive force of the manufactured permanent magnet was 11-20 kOe. FIG. 7 is an example of a graph showing the relationship between the Co concentration and the maximum energy product. As shown in FIG. 7, it can be seen that the maximum energy product increases in the sample with Co concentration in the range of 0.2 to 10% by weight as compared to the sample without Co.
　上述した実施形態や実施例は、本発明の理解を助けるために説明したものであり、本発明は、記載した具体的な構成のみに限定されるものではない。例えば、実施形態の構成の一部を当業者の技術常識の構成に置き換えることが可能であり、また、実施形態の構成に当業者の技術常識の構成を加えることも可能である。すなわち、本発明は、本明細書の実施形態や実施例の構成の一部について、発明の技術的思想を逸脱しない範囲で、削除・他の構成に置換・他の構成の追加をすることが可能である。 The embodiments and examples described above are described in order to help the understanding of the present invention, and the present invention is not limited to only the specific configurations described. For example, it is possible to replace part of the configuration of the embodiment with the configuration of the common sense of the person skilled in the art, and it is also possible to add the configuration of the common sense of the person skilled in the art to the configuration of the embodiment. That is, the present invention may delete, add, or substitute other configurations to other configurations without departing from the technical concept of the invention with respect to a part of the configurations of the embodiments and examples of the present specification. It is possible.
　1…結晶粒、2…粒界。 1 ... grain, 2 ... grain boundary.

Claims (5)

  1. 　希土類元素を含有しない永久磁石であって、
    第３の元素が拡散したFeNi規則相を含有し、
    前記第３の元素は、炭素、窒素またはコバルトであり、
    前記第３の元素の濃度は、前記永久磁石の表面から内部に向かって減少する、および／または前記FeNi規則相の結晶粒の表面から内部に向かって減少することを特徴とする永久磁石。     It is a permanent magnet containing no rare earth element,
    Contains the FeNi ordered phase in which the third element is diffused,
    The third element is carbon, nitrogen or cobalt,
    A permanent magnet characterized in that the concentration of the third element decreases from the surface of the permanent magnet toward the inside and / or decreases from the surface of the crystal grains of the FeNi ordered phase toward the inside.
  2. 　請求項１に記載の永久磁石において、
    前記FeNi規則相の規則度が0.05以上1.0以下の範囲であることを特徴とする永久磁石。     In the permanent magnet according to claim 1,
    A permanent magnet characterized in that the degree of order of the FeNi ordered phase is in the range of 0.05 or more and 1.0 or less.
  3. 　請求項１または請求項２に記載の永久磁石において、
    前記第３の元素が炭素であり、
    前記表面の炭素濃度が0.5重量％以上2重量％以下であることを特徴とする永久磁石。     The permanent magnet according to claim 1 or 2
    The third element is carbon,
    A permanent magnet having a carbon concentration of 0.5% by weight or more and 2% by weight or less on the surface.
  4. 　請求項１または請求項２に記載の永久磁石において、
    前記第３の元素が窒素であり、
    前記表面の窒素濃度が1.0重量％以上2重量％以下であることを特徴とする永久磁石。     The permanent magnet according to claim 1 or 2
    The third element is nitrogen,
    A permanent magnet having a nitrogen concentration of 1.0% by weight or more and 2% by weight or less on the surface.
  5. 　請求項１または請求項２に記載の永久磁石において、
    前記第３の元素がコバルトであり、
    前記表面のコバルト濃度が0.2重量％以上10重量％以下であることを特徴とする永久磁石。     The permanent magnet according to claim 1 or 2
    The third element is cobalt,
    A permanent magnet having a cobalt concentration of 0.2% by weight or more and 10% by weight or less on the surface.
PCT/JP2018/023430 2017-06-21 2018-06-20 Permanent magnet WO2018235856A1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2014105376A (en) * 2012-11-29 2014-06-09 Kyushu Univ METHOD OF MANUFACTURING L10 TYPE FeNi REGULAR ALLOY AND L10 TYPE FeNi REGULAR ALLOY
WO2016036856A1 (en) * 2014-09-02 2016-03-10 Northeastern University Rare-earth-free permanent magnetic materials based on fe-ni
WO2016171232A1 (en) * 2015-04-23 2016-10-27 国立大学法人東北大学 FeNi ALLOY COMPOSITION CONTAINING L10-TYPE FeNi ORDERED PHASE, METHOD FOR PRODUCING FeNi ALLOY COMPOSITION INCLUDING L10-TYPE FeNi ORDERED PHASE, FeNi ALLOY COMPOSITION HAVING AMORPHOUS MAIN PHASE, PARENT ALLOY OF AMORPHOUS MEMBER, AMORPHOUS MEMBER, MAGNETIC MATERIAL, AND METHOD FOR PRODUCING MAGNETIC MATERIAL
JP2017075388A (en) * 2015-10-14 2017-04-20 株式会社デンソー FeNi REGULAR ALLOY, MANUFACTURING METHOD OF FeNi REGULAR ALLOY AND MAGNETIC MATERIAL CONTAINING FeNi REGULAR ALLOY

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2014105376A (en) * 2012-11-29 2014-06-09 Kyushu Univ METHOD OF MANUFACTURING L10 TYPE FeNi REGULAR ALLOY AND L10 TYPE FeNi REGULAR ALLOY
WO2016036856A1 (en) * 2014-09-02 2016-03-10 Northeastern University Rare-earth-free permanent magnetic materials based on fe-ni
WO2016171232A1 (en) * 2015-04-23 2016-10-27 国立大学法人東北大学 FeNi ALLOY COMPOSITION CONTAINING L10-TYPE FeNi ORDERED PHASE, METHOD FOR PRODUCING FeNi ALLOY COMPOSITION INCLUDING L10-TYPE FeNi ORDERED PHASE, FeNi ALLOY COMPOSITION HAVING AMORPHOUS MAIN PHASE, PARENT ALLOY OF AMORPHOUS MEMBER, AMORPHOUS MEMBER, MAGNETIC MATERIAL, AND METHOD FOR PRODUCING MAGNETIC MATERIAL
JP2017075388A (en) * 2015-10-14 2017-04-20 株式会社デンソー FeNi REGULAR ALLOY, MANUFACTURING METHOD OF FeNi REGULAR ALLOY AND MAGNETIC MATERIAL CONTAINING FeNi REGULAR ALLOY

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