WO2015079981A1 - Powder mixture for powder magnetic core and powder magnetic core - Google Patents

Powder mixture for powder magnetic core and powder magnetic core Download PDF

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WO2015079981A1
WO2015079981A1 PCT/JP2014/080548 JP2014080548W WO2015079981A1 WO 2015079981 A1 WO2015079981 A1 WO 2015079981A1 JP 2014080548 W JP2014080548 W JP 2014080548W WO 2015079981 A1 WO2015079981 A1 WO 2015079981A1
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powder
iron
soft magnetic
based soft
mass
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PCT/JP2014/080548
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French (fr)
Japanese (ja)
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三谷　宏幸
北条　啓文
祐司 谷口
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株式会社神戸製鋼所
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    • 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
    • H01F1/12—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 soft-magnetic materials
    • H01F1/14—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 soft-magnetic materials metals or alloys
    • H01F1/20—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 soft-magnetic materials metals or alloys in the form of particles, e.g. powder
    • H01F1/22—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 soft-magnetic materials metals or alloys in the form of particles, e.g. powder pressed, sintered, or bound together
    • H01F1/24—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 soft-magnetic materials metals or alloys in the form of particles, e.g. powder pressed, sintered, or bound together the particles being insulated
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/09—Mixtures of metallic powders
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/16—Metallic particles coated with a non-metal
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
    • H01F41/0206—Manufacturing of magnetic cores by mechanical means
    • H01F41/0246—Manufacturing of magnetic circuits by moulding or by pressing powder
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C2202/00—Physical properties
    • C22C2202/02—Magnetic
    • 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
    • H01F1/12—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 soft-magnetic materials
    • H01F1/14—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 soft-magnetic materials metals or alloys
    • H01F1/20—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 soft-magnetic materials metals or alloys in the form of particles, e.g. powder
    • H01F1/22—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 soft-magnetic materials metals or alloys in the form of particles, e.g. powder pressed, sintered, or bound together
    • H01F1/24—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 soft-magnetic materials metals or alloys in the form of particles, e.g. powder pressed, sintered, or bound together the particles being insulated
    • H01F1/26—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 soft-magnetic materials metals or alloys in the form of particles, e.g. powder pressed, sintered, or bound together the particles being insulated by macromolecular organic substances

Definitions

  • the present invention improves the compressibility at the time of molding, and enables to suppress the powder within a predetermined iron loss (hysteresis loss + eddy current loss), and a powder using the mixed powder. It is about magnetic core.
  • the dust core is used as an iron core for devices such as reactors and motors that are used in alternating current.
  • this iron core is excited with an alternating current (for example, a frequency of 1 to 10 kHz), iron loss (hysteresis loss + eddy current loss) occurs.
  • an alternating current for example, a frequency of 1 to 10 kHz
  • iron loss hysteresis loss + eddy current loss
  • the ratio of eddy current loss to iron loss also increases.
  • Patent Documents 2 to 6 a technique for covering the surface of the soft magnetic powder particles with an insulating material is also disclosed with the aim of improving the density of the green compact while enhancing the insulation of the electrically insulating layer formed on the surface of the soft magnetic powder particles.
  • Patent Document 2 Patent Document 5, and Patent Document 6, as compared with the technique disclosed in Patent Document 1, an electrical insulating layer formed on the surface of the soft magnetic powder particles is used.
  • the amount of organic insulating material used is reduced. Therefore, the density of the molded body is also slightly improved (that is, the compressibility is also slightly improved), and the magnetic properties (permeability and magnetic flux density) are improved.
  • the electrically insulating layer formed on the surface of the soft magnetic powder particles is an inorganic insulating material, the load applied to the mold during molding is reduced.
  • the raw material powder has a low compressibility, and it is difficult to reduce the molding pressure to obtain a predetermined density as a molded body.
  • An object of the present invention is to use a mixed powder for a powder magnetic core, which can improve the compressibility during molding and can be suppressed within a predetermined iron loss (hysteresis loss + eddy current loss), and the mixed powder.
  • the object is to provide a dust core.
  • the powder mixture for a powder magnetic core comprises: Including iron-based soft magnetic powder A coated with an insulating coating and iron-based soft magnetic powder B not coated with an insulating coating, A mixed powder for a dust core, wherein a mixing ratio of the iron-based soft magnetic powder A and the iron-based soft magnetic powder B satisfies the following formula (1). 1% by mass ⁇ [mass of iron-based soft magnetic powder B / (mass of iron-based soft magnetic powder A + mass of iron-based soft magnetic powder B)] ⁇ 100 ⁇ 5% by mass --- (1)
  • the powder mixture for a dust core according to the second invention is: An iron-based soft magnetic powder in which an iron-based soft magnetic powder having a particle size of 600 ⁇ m or less and a particle size of less than 75 ⁇ m is 2% by mass or less is coated with an insulating coating. Including powder C and iron-based soft magnetic powder D not coated with an insulating coating, A mixed powder for a dust core, wherein a mixing ratio of the iron-based soft magnetic powder C and the iron-based soft magnetic powder D satisfies the following formula (2). 1 mass% ⁇ [mass of iron-based soft magnetic powder D / (mass of iron-based soft magnetic powder C + mass of iron-based soft magnetic powder D)] ⁇ 100 ⁇ 30 mass% ⁇ (2)
  • the powder mixture for powder magnetic core according to the third invention is the powder mixture for powder magnetic core according to the first or second invention, wherein the insulating coating is at least an inorganic insulating coating.
  • the powder mixture for powder magnetic core according to the fourth invention is the powder mixture for powder magnetic core according to any one of the first to third inventions, wherein a lubricant is mixed in the powder mixture for powder magnetic core. It is characterized by.
  • the mixed powder for a powder magnetic core according to the fifth invention is An iron-based soft magnetic powder having a particle diameter of 600 ⁇ m or less is used, and an iron-based soft magnetic powder E in which an inorganic insulating coating and a heat-resistant resin coating are coated in this order on the surface of the iron-based soft magnetic powder and the inorganic insulating And iron-based soft magnetic powder F not coated with a heat-resistant resin film, A mixed powder for a dust core, wherein a mixing ratio of the iron-based soft magnetic powder E and the iron-based soft magnetic powder F satisfies the following expression (3). 3% by mass ⁇ [mass of iron-based soft magnetic powder F / (mass of iron-based soft magnetic powder E + iron-based soft magnetic powder F Mass)] ⁇ 100 ⁇ 10 mass% --- (3)
  • the powder mixture for powder magnetic core according to the sixth invention is the powder mixture for powder magnetic core according to the fifth invention, wherein a lubricant is applied to the inner wall surface of a mold for compression molding, and the powder mixture for powder magnetic core Is characterized in that no lubricant is added.
  • a powder magnetic core according to a seventh aspect of the present invention is obtained by compression molding the powder mixture for a powder magnetic core according to any one of the first to sixth aspects, and the molded body obtained by the compression molding is annealed at a predetermined temperature. It is a dust core characterized by
  • the powder mixture for a dust core according to the first invention is Including iron-based soft magnetic powder A coated with an insulating coating and iron-based soft magnetic powder B not coated with an insulating coating, A mixed powder for a dust core, wherein a mixing ratio of the iron-based soft magnetic powder A and the iron-based soft magnetic powder B satisfies the following formula (1). 1% by mass ⁇ [mass of iron-based soft magnetic powder B / (mass of iron-based soft magnetic powder A + mass of iron-based soft magnetic powder B)] ⁇ 100 ⁇ 5% by mass --- (1)
  • the powder mixture for a dust core according to the second invention is: An iron-based soft magnetic powder in which an iron-based soft magnetic powder having a particle size of 600 ⁇ m or less and a particle size of less than 75 ⁇ m is 2% by mass or less is coated with an insulating coating. Including powder C and iron-based soft magnetic powder D not coated with an insulating coating, A mixed powder for a dust core, wherein a mixing ratio of the iron-based soft magnetic powder C and the iron-based soft magnetic powder D satisfies the following formula (2). 1 mass% ⁇ [mass of iron-based soft magnetic powder D / (mass of iron-based soft magnetic powder C + mass of iron-based soft magnetic powder D)] ⁇ 100 ⁇ 30 mass% ⁇ (2)
  • the powder mixture for powder magnetic cores according to the fifth invention is An iron-based soft magnetic powder having a particle diameter of 600 ⁇ m or less is used, and an iron-based soft magnetic powder E in which an inorganic insulating coating and a heat-resistant resin coating are coated in this order on the surface of the iron-based soft magnetic powder and the inorganic insulating And iron-based soft magnetic powder F not coated with a heat-resistant resin film, A mixed powder for a dust core, wherein a mixing ratio of the iron-based soft magnetic powder E and the iron-based soft magnetic powder F satisfies the following expression (3).
  • 3% by mass ⁇ [mass of iron-based soft magnetic powder F / (mass of iron-based soft magnetic powder E + mass of iron-based soft magnetic powder F)] ⁇ 100 ⁇ 10% by mass --- (3)
  • the powder magnetic core according to the present invention is characterized in that the powder mixture for powder magnetic core is compression molded, and a molded body obtained by the compression molding is annealed at a predetermined temperature.
  • FIG. 1 is an explanatory diagram for explaining a relationship between a molding pressure and a compact density when the raw powder mixing ratio of the powder mixture for a powder magnetic core according to the first embodiment of the present invention is changed.
  • FIG. 2 is a characteristic diagram (forming pressure 800 MPa, excitation magnetic field 0.1 T, excitation frequency 10 kHz) showing the relationship between the raw powder mixing ratio and the iron loss in the powder magnetic core according to the first embodiment of the present invention.
  • FIG. 3 is a characteristic diagram (forming pressure 1200 MPa, excitation magnetic field 0.1 T, excitation frequency 10 kHz) showing the relationship between the raw powder mixing ratio and the iron loss in the powder magnetic core according to Embodiment 1 of the present invention.
  • FIG. 1 is an explanatory diagram for explaining a relationship between a molding pressure and a compact density when the raw powder mixing ratio of the powder mixture for a powder magnetic core according to the first embodiment of the present invention is changed.
  • FIG. 2 is a characteristic diagram (forming pressure 800 MPa, excitation magnetic field 0.1
  • FIG. 4 is a characteristic diagram (forming pressure 800 MPa, excitation magnetic field 0.2 T, excitation frequency 1 kHz) showing the relationship between the raw powder mixing ratio and the iron loss in the powder magnetic core according to Embodiment 1 of the present invention.
  • FIG. 5 is a characteristic diagram (forming pressure 1200 MPa, excitation magnetic field 0.2 T, excitation frequency 1 kHz) showing the relationship between the raw powder mixing ratio and the iron loss in the powder magnetic core according to Embodiment 1 of the present invention.
  • FIG. 6 is a characteristic diagram (forming pressure 800 MPa, excitation magnetic field 0.2 T, excitation frequency 5 kHz) showing the relationship between the raw powder mixing ratio and the iron loss in the powder magnetic core according to the first embodiment of the present invention.
  • FIG. 7 is a characteristic diagram (forming pressure 1200 MPa, excitation magnetic field 0.2 T, excitation frequency 5 kHz) showing the relationship between the raw powder mixing ratio and the iron loss in the powder magnetic core according to the first embodiment of the present invention.
  • FIG. 8 is an explanatory diagram for explaining the relationship between the molding pressure and the compact density in the iron-based soft magnetic powder D according to the second embodiment of the present invention.
  • FIG. 9 is a characteristic diagram (forming pressure 900 MPa, excitation magnetic field 0.1 T, excitation frequency 10 kHz) showing the relationship between the raw powder mixing ratio and the iron loss in the powder magnetic core according to the second embodiment of the present invention.
  • FIG. 10 is a characteristic diagram (forming pressure 900 MPa, excitation magnetic field 0.2 T, excitation frequency 1 kHz) showing the relationship between the raw powder mixing ratio and the iron loss in the powder magnetic core according to the second embodiment of the present invention.
  • FIG. 11 is a characteristic diagram (forming pressure 900 MPa, excitation magnetic field 0.2 T, excitation frequency 5 kHz) showing the relationship between the raw powder mixing ratio and the iron loss in the powder magnetic core according to the second embodiment of the present invention.
  • FIG. 12 is an explanatory diagram for explaining the relationship between the compact density and the magnetic flux density when the raw powder mixing ratio of the powder mixture for powder magnetic core according to the second embodiment of the present invention is changed.
  • FIG. 10 is a characteristic diagram (forming pressure 900 MPa, excitation magnetic field 0.2 T, excitation frequency 1 kHz) showing the relationship between the raw powder mixing ratio and the iron loss in the powder magnetic core according to the second embodiment of the present invention.
  • FIG. 11 is a characteristic diagram (forming pressure 900 MPa, excitation
  • FIG. 13 is an explanatory diagram for explaining the relationship between the raw powder mixing ratio and the compact density when the particle size of the raw powder F contained in the powder mixture for powder magnetic core according to Embodiment 3 of the present invention is changed.
  • (A) is a molding pressure of 800 MPa
  • (b) is a molding pressure of 1000 MPa
  • (c) is a molding pressure of 1200 MPa.
  • FIG. 14 is a characteristic diagram (molding pressure 1200 MPa) showing the relationship between the raw powder mixing ratio and the magnetic flux density in the powder magnetic core (when the particle size of the raw powder F is changed) according to Embodiment 3 of the present invention.
  • FIG. 1200 MPa characteristic diagram showing the relationship between the raw powder mixing ratio and the magnetic flux density in the powder magnetic core (when the particle size of the raw powder F is changed) according to Embodiment 3 of the present invention.
  • FIG. 15 is an explanatory diagram (molding pressure 1200 MPa) for explaining the relationship between the compact density and the magnetic flux density in the dust core according to the third embodiment of the present invention (when the particle size of the raw powder F is changed). is there.
  • FIG. 16 is a characteristic diagram (forming pressure 1200 MPa, excitation magnetic field 0) showing the relationship between the raw powder mixing ratio and the iron loss in the powder magnetic core (when the particle size of the raw powder F is changed) according to Embodiment 3 of the present invention.
  • (1T, excitation frequency 10 kHz) (a) is raw powder F1, (b) is raw powder F2, and (c) is raw powder F3.
  • FIG. 1T excitation frequency 10 kHz
  • FIG. 17 is a characteristic diagram (forming pressure 1200 MPa, excitation magnetic field 0) showing the relationship between the raw powder mixing ratio and the iron loss in the powder magnetic core (when the particle size of the raw powder F is changed) according to Embodiment 3 of the present invention.
  • (2T, excitation frequency 1 kHz) (a) is raw powder F1, (b) is raw powder F2, and (c) is raw powder F3.
  • FIG. 18 is a characteristic diagram (forming pressure 1200 MPa, excitation magnetic field 0) showing the relationship between the raw powder mixing ratio and the iron loss in the powder magnetic core (when the particle size of the raw powder F is changed) according to Embodiment 3 of the present invention.
  • (2T, excitation frequency 5 kHz) (a) is raw powder F1, (b) is raw powder F2, and (c) is raw powder F3.
  • the powder mixture for powder magnetic core according to Embodiment 1 of the present invention (that is, the powder mixture for powder magnetic core according to the first invention) is coated with an iron-based soft magnetic powder A coated with an insulation coating and an insulation coating.
  • Iron-based soft magnetic powder B that has not been made,
  • the mixing ratio of the iron-based soft magnetic powder A and the iron-based soft magnetic powder B satisfies the following formula (1). 1% by mass ⁇ [mass of iron-based soft magnetic powder B / (mass of iron-based soft magnetic powder A + mass of iron-based soft magnetic powder B)] ⁇ 100 ⁇ 5% by mass --- (1)
  • the compressibility at the time of forming into a compact as a powder magnetic core is improved ⁇ for example, in the conventional case (iron-based soft magnetic powder coated with an inorganic insulating coating)
  • the molding density is improved as compared with the conventional case while employing the same molding pressure (hereinafter sometimes referred to as molding pressure) as in the case of only A). Therefore, the magnetic permeability and magnetic flux density are improved as compared with the conventional case.
  • a predetermined iron loss ⁇ hysteresis loss (hereinafter referred to as “loss loss”) in the powder magnetic core can be improved even though it is possible to improve the compressibility at the time of forming into a compact. ),
  • the iron-based soft magnetic powder used in the present invention is a ferromagnetic metal powder. Specific examples thereof include pure iron powder, iron-based alloy powder (Fe—A1 alloy, Fe—Si alloy, Sendust, Permalloy, etc.). ) And amorphous powder. Such a soft magnetic powder can be produced, for example, by reducing it into fine particles by the atomizing method, reducing it, and then pulverizing it. In the present invention, in principle, any particle size used in ordinary powder metallurgy exhibits its effects without depending on the particle size distribution.
  • a component having a large particle size for example, 250 ⁇ m or more and 600 ⁇ m or less
  • An iron-based soft magnetic powder is more preferred (see Table 1 below for details).
  • the iron-based soft magnetic powder is first sieved using a sieve having an aperture of 600 ⁇ m in accordance with “Metal Powder Sieve Analysis Test Method” (JPMA PO2-1992) prescribed by the Japan Powder Metallurgy Industry Association. After that, sieving was sequentially performed using a sieve having an opening of 250 ⁇ m to 45 ⁇ m corresponding to the particle size shown in Table 1 below.
  • the iron-based soft magnetic powder B in the present invention refers to a material in which the surface of the iron-based soft magnetic powder is not coated with an insulating film as described later. This is also called raw powder.
  • the iron-based soft magnetic powder A in the present invention refers to a material obtained by coating the surface of the iron-based soft magnetic powder with the following insulating coating.
  • the said insulating film in this invention is an inorganic type insulating film at least.
  • the phosphoric acid-based chemical conversion coating as the inorganic insulating coating is more preferable because it has good wettability with respect to the iron-based soft magnetic powder and can uniformly coat the surface of the iron-based soft magnetic powder with this coating. .
  • water 50 parts (meaning parts by mass; the same applies hereinafter), NaH 2 PO 4 : 30 parts, H 3 PO 4 as the phosphoric acid-based chemical film treatment solution.
  • 10 parts, (NH 2 OH) 2 ⁇ H 2 SO 4 : 10 parts, Co 3 (PO 4 ) 2 : 10 parts were mixed, and a treatment solution diluted 20 times with water was used. Further, 5 parts of this treatment liquid was mixed with 100 parts of the iron-based soft magnetic powder and dried at 200 ° C. in the atmosphere.
  • the thickness of the phosphoric acid-based chemical conversion film is 10 to 100 nm.
  • FIG. 1 is an explanatory diagram for explaining a relationship between a molding pressure and a compact density when the raw powder mixing ratio of the powder mixture for a powder magnetic core according to the first embodiment of the present invention is changed.
  • the mixed powder for the powder magnetic core ⁇ mixed powder of iron-based soft magnetic powder A and iron-based soft magnetic powder B (raw powder) ⁇ that forms a compact uses pure iron powder as the iron-based soft magnetic powder. ing. Moreover, the particle size distribution of the pure iron powder used is as shown in Table 1 above. Moreover, the insulating coating which coat
  • the powder mixture for powder magnetic core After adding 0.3% by mass of stearamide as a lubricant to the powder mixture for powder magnetic core, it is put in a mold (outside diameter ⁇ 45 mm ⁇ inside diameter ⁇ 33 mm ⁇ height 5 mm), and the molding pressure is 800 at room temperature. , 1000 and 1200 MPa, and each was press-molded into a toroidal shape to obtain a molded body.
  • This molded body is annealed in the atmosphere at a predetermined temperature (for example, 350 ° C., 30 minutes) to obtain a dust core.
  • the raw powder mixing ratio of this powder mixture for powder magnetic core is 0% by mass for each molding pressure ⁇ that is, iron-based soft magnetic powder A (pure iron coated with a phosphate chemical conversion coating).
  • the raw powder mixing ratio is defined as [mass of iron-based soft magnetic powder B / (mass of iron-based soft magnetic powder A + mass of iron-based soft magnetic powder B)] ⁇ 100.
  • the present invention shows that a low molding pressure is sufficient to obtain a predetermined molded body density. Therefore, even at a low molding pressure, the magnetic permeability and the magnetic flux density are improved as compared with the conventional one, and the technical significance thereof is very large.
  • a predetermined iron loss ⁇ hysteresis loss (hereinafter sometimes referred to as hiss loss) in the dust core + Eddy current loss (hereinafter also referred to as eddy loss) ⁇ (for example, within 5% of iron loss when composed only of iron-based soft magnetic powder A coated with an inorganic insulating coating) It is necessary to confirm the range of the raw powder mixing ratio that can be suppressed to an increase). This will be described in detail in Example 2 below.
  • the raw powder mixing ratio in the range of 1% by mass to 5% by mass, the raw powder mixing ratio is 0% by mass ⁇ that is, iron-based soft magnetic powder A (phosphate-based chemical conversion). It was proved that the increase was within 5% of the iron loss in only the pure iron powder coated with the coating.
  • the iron-based soft magnetic powder A coated with the insulating coating and the iron-based soft magnetic powder B not coated with the insulating coating are included, and the iron-based soft magnetic powder A and the iron-based soft magnetic powder B.
  • a mixed powder for a powder magnetic core in which the mixing ratio of B satisfies the following formula (1) is used, the compressibility at the time of molding is improved, and it is suppressed within a predetermined iron loss (hysteresis loss + eddy current loss). It is speculated that the following reasons can be considered to make this possible.
  • 1% by mass ⁇ [mass of iron-based soft magnetic powder B / (mass of iron-based soft magnetic powder A + mass of iron-based soft magnetic powder B)] ⁇ 100 ⁇ 5% by mass --- (1)
  • the iron-based soft magnetic powder A coated with the insulating coating appropriately surrounds the iron-based soft magnetic powder B not coated with the insulating coating. It is assumed that it is caused by presenting. That is, “the effect of improving the compressibility at the time of molding due to the presence of the iron-based soft magnetic powder B having good deformability” and “the effect of ensuring appropriate separability between the iron-based soft magnetic powders B” were confounded together. I guess that.
  • the powder mixture for powder magnetic core according to Embodiment 2 of the present invention (that is, the powder mixture for powder magnetic core according to the second invention) has a particle size of 600 ⁇ m or less and a particle size ratio of less than 75 ⁇ m is 2.
  • iron-based soft magnetic powder having a mass% or less, an iron-based soft magnetic powder C coated with an insulating coating and an iron-based soft magnetic powder D not coated with an insulating coating.
  • the specific surface area of the powder is further reduced, and the powder in the compression process Friction and work hardening in between are reduced, and the density of the molded body is further improved even at the same molding pressure. Therefore, compared to the case of the first embodiment, not only the amount of the iron-based soft magnetic powder in the molded body is increased but also the voids are reduced as compared with the case where the powder adopted in the first embodiment is adopted. Thus, the magnetic flux density and the magnetic permeability are further improved.
  • the structure of the powder magnetic core according to the present embodiment that is, the structure in which the iron-based soft magnetic powder D not coated with the insulating coating surrounds the iron-based soft magnetic powder C coated with the insulating coating
  • the predetermined iron loss ⁇ that is, the increase in iron loss relative to the iron loss when the raw powder mixing ratio is 0% by mass is 5% or less ⁇
  • the improvement of the magnetic flux density can be expected more than in the case where the
  • the material of the iron-based soft magnetic powder in the present embodiment can be the same as that of the iron-based soft magnetic powder employed in the first embodiment.
  • it since it is intended to further improve the compressibility at the time of forming into a molded body while suppressing to a predetermined iron loss, it contains more components with a large particle size (for example, 106 ⁇ m or more and 600 ⁇ m or less),
  • iron-based soft magnetic powder having a particle size of less than 75 ⁇ m of 2% or less is more preferable (see Table 4 below for details).
  • the iron-based soft magnetic powder is first sieved using a sieve having an aperture of 600 ⁇ m in accordance with “Metal Powder Sieve Analysis Test Method” (JPMA PO2-1992) prescribed by the Japan Powder Metallurgy Industry Association. After that, sieving was sequentially performed using a sieve having an opening of 250 ⁇ m to 106 ⁇ m corresponding to the particle sizes shown in Table 4 below.
  • the iron-based soft magnetic powder defined in the present embodiment ⁇ roughened iron-based soft magnetic powder (that is, the abundance ratio of a particle size of substantially 75 ⁇ m to 600 ⁇ m and less than 75 ⁇ m). Of iron-based soft magnetic powder) is 2 mass% or less.
  • the iron-based soft magnetic powder C in this embodiment is obtained by coating the surface of the iron-based soft magnetic powder with the above-described insulating coating (that is, the same insulating coating as used in Embodiment 1). Point to and say.
  • the said insulation film in this embodiment is an inorganic insulation film at least similarly to Embodiment 1.
  • the phosphoric acid-based chemical conversion coating as the inorganic insulating coating is more preferable because it has good wettability with respect to the iron-based soft magnetic powder and can uniformly coat the surface of the iron-based soft magnetic powder with this coating. .
  • the same treatment liquid as in Embodiment 1 was used. Further, 5 parts of this treatment liquid was mixed with 100 parts of the iron-based soft magnetic powder and dried at 200 ° C. in the atmosphere. As a result, the thickness of the phosphoric acid-based chemical conversion film becomes 10 to 100 nm.
  • FIG. 8 is an explanatory diagram for explaining the relationship between the molding pressure and the compact density of the iron-based soft magnetic powder D according to the second embodiment of the present invention.
  • FIG. 8 when the iron-based soft magnetic powder D (that is, the coarse-grained iron-based soft magnetic powder D) is used, only the raw powder shown in FIG. 1 (shown simultaneously in FIG. 8). 3), it can be seen that the density of the molded body is higher in the low molding pressure region (for example, 900 MPa or less). This is because, as already described above, the specific surface area of the powder is further reduced, and friction between the powder and work hardening are reduced during the compression process. Therefore, as compared with the case where the powder employed in the first embodiment is employed, not only the amount of iron-based soft magnetic powder in the molded body is increased even in a lower molding pressure region, but also in a lower molding pressure region.
  • the low molding pressure region for example, 900 MPa or less
  • the magnetic flux density (see FIG. 12 for details) and the magnetic permeability (not shown) are further improved in the region of lower molding pressure than in the case of the first embodiment. Suggests. Since this can be expected to reduce the size of electromagnetic components, its technical significance is very large.
  • FIG. 9 to 11 are characteristic diagrams showing the relationship between the raw powder mixing ratio and the iron loss in the dust core according to the present embodiment.
  • the iron-based soft magnetic powder used for the dust core (measurement sample) for measuring the iron loss is the one detailed in Table 4 above.
  • a dust core using the iron-based soft magnetic powder shown in Table 4 that is, an iron-based soft magnetic powder having a particle size of 600 ⁇ m or less and a particle size of less than 75 ⁇ m is 2% by mass or less).
  • the mold After adding 0.3% by mass of ethylenebislauric acid amide as a lubricant to the mixed powder ⁇ mixed powder of iron-based soft magnetic powder C and iron-based soft magnetic powder D (raw powder) ⁇ , the mold (outer diameter ( ⁇ 45 mm ⁇ inner diameter ⁇ 33 mm ⁇ height 5 mm) and press molded into a toroidal shape at a molding pressure of 900 MPa at room temperature to obtain a molded body. This molded body is annealed in the atmosphere at a predetermined temperature (for example, 350 ° C., 30 minutes) to obtain a dust core. As shown in FIG. 9 to FIG.
  • the raw powder mixing ratio of this powder mixture for powder magnetic cores is 0% by mass ⁇ that is, iron-based soft magnetic powder C (pure iron powder coated with a phosphate chemical conversion coating). ) Only ⁇ , 5% by mass, 10% by mass, 20% by mass, 30% by mass, 50% by mass, 75% by mass and 100% by mass (that is, iron-based soft magnetic powder D only).
  • the raw powder mixing ratio is defined as [mass of iron-based soft magnetic powder D / (mass of iron-based soft magnetic powder C + mass of iron-based soft magnetic powder D)] ⁇ 100.
  • An AC BH analyzer was used to measure the iron loss.
  • Table 5 below shows the measurement conditions and various specifications of the molding pressure (molding pressure) when the dust core was formed.
  • the raw powder mixing ratio is in the range of 0% by mass to 30% by mass.
  • a predetermined iron loss when using the iron-based soft magnetic powder employed in Embodiment 1 that is, iron when the raw powder mixing ratio is 0% by mass
  • the raw powder mixing ratio excludes 0% by mass, that is, at least 1% by mass or more, the effect of the present invention is exhibited, and the compact density due to the improvement in compressibility is further improved. An improvement is observed.
  • the raw powder mixing ratio is at least 1% by mass or more, the magnetic flux density is equal to or higher than the level when the raw powder mixing ratio is 0% by mass.
  • the mixed powder for a dust core according to Embodiment 3 of the present invention uses an iron-based soft magnetic powder having a particle diameter of 600 ⁇ m or less.
  • Including A mixed powder for a dust core wherein a mixing ratio of the iron-based soft magnetic powder E and the iron-based soft magnetic powder F satisfies the following expression (3).
  • 3% by mass ⁇ [mass of iron-based soft magnetic powder F / (mass of iron-based soft magnetic powder E + mass of iron-based soft magnetic powder F)] ⁇ 100 ⁇ 10% by mass --- (3)
  • the mixed ratio of the double-coated iron-based soft magnetic powder E and the non-double-coated iron-based soft magnetic powder F satisfies the above formula (3), a double-coated film is used.
  • the friction and work-hardening between the powders during the compression process are less than or equal to those of the mixed powder adopted in Embodiment 2, and the compact density Will improve to the same or better level. That is, not only the amount of the iron-based soft magnetic powder in the molded body is increased more than the mixed powder employed in the first embodiment, but also the gap is reduced, so that the magnetic flux is smaller than that in the first embodiment. The density is further improved.
  • a structure exhibited by a powder magnetic core prepared by compression molding using a mixed powder as in the present embodiment ⁇ that is, an iron-based soft magnetic powder not coated with a double-coated iron-based soft magnetic powder E F (structure presumed to be surrounded by raw powder F) ⁇ , the predetermined iron loss when the iron-based soft magnetic powder employed in Embodiment 1 is used ⁇ ie, the raw powder mixing ratio is 0 mass %,
  • the iron-based soft magnetic powder F is incorporated into the compact as a dust core (ie, the iron-based soft magnetic powder F).
  • the addition ratio of the magnetic powder F) can be further increased.
  • the improvement of the magnetic flux density can be expected more than in the case where the iron-based soft magnetic powder employed in the first embodiment is used.
  • this effect is relatively small in the particle size dependence of the raw powder F.
  • the material of the iron-based soft magnetic powder in this embodiment can be the same as the iron-based soft magnetic powder employed in the first embodiment.
  • the mixed powder contains the double-coated iron-based soft magnetic powder E, while suppressing the predetermined iron loss, while aiming to further improve the compressibility when molding into a molded body, Compared with Embodiments 1 and 2, the particle size distribution of the iron-based soft magnetic powder is distributed over a wide range of particle sizes of 600 ⁇ m or less (see Table 6 below for details).
  • the iron-based soft magnetic powder is first sieved using a sieve having an aperture of 600 ⁇ m in accordance with “Metal Powder Sieve Analysis Test Method” (JPMA PO2-1992) prescribed by the Japan Powder Metallurgy Industry Association.
  • F1 raw powder coarse powder
  • F2 raw flour fines
  • F3 raw powder full particle size
  • the iron-based soft magnetic powder E in the present embodiment refers to the surface of the iron-based soft magnetic powder and the above-described inorganic insulating coating (that is, the same insulating coating as that employed in Embodiment 1) and heat resistance.
  • a resin film (described in detail later) refers to what is coated in this order.
  • the phosphoric acid-based chemical conversion coating (lower layer) as the inorganic insulating coating in this embodiment has good wettability to the iron-based soft magnetic powder, and the surface of the iron-based soft magnetic powder is uniformly coated with this coating. It is more preferable because it is possible.
  • the same treatment liquid as that in Embodiment 1 was used. Further, 5 parts of this treatment liquid was mixed with 100 parts of the iron-based soft magnetic powder and dried at 200 ° C. in the atmosphere. Thereby, the thickness of the phosphoric acid-based chemical conversion film (lower layer) becomes 10 to 100 nm.
  • a silicone resin coating as the following heat-resistant resin coating is further formed on the surface. Formed. Below, this silicone resin film (upper layer) is explained in full detail.
  • the silicone resin coating (upper layer) was formed by forming a silicone resin solution in which a silicone resin was dissolved in a petroleum-based organic solvent such as alcohols, toluene, and xylene, and the above-described phosphoric acid-based chemical conversion coating (lower layer) on the surface. This was performed by mixing with iron-based soft magnetic powder and then evaporating the organic solvent or the like as necessary. Thereby, the thickness of a predetermined silicone resin film (upper layer) is obtained.
  • the thickness of the silicone resin coating (upper layer) is preferably 1 to 200 nm, more preferably 20 to 150 nm.
  • silicone resin used in the present invention a conventionally known silicone resin can be used.
  • a conventionally known silicone resin can be used as commercially available products.
  • Methyl phenyl silicone resin for example, KR300 manufactured by Shin-Etsu Chemical Co., Ltd.
  • methyl silicone resin having no phenyl group for example, SR2400 manufactured by Toray Dow Corning Co., Ltd., KR251, KR400 manufactured by Shin-Etsu Chemical Co., Ltd.
  • KR220L, KR242A, KR240, KR500, KC89, etc. are more preferable.
  • KR220L and SR2400 are particularly preferable.
  • FIG. 13 is a view for explaining the relationship between the raw powder mixing ratio and the compact density when the particle size of raw powder F contained in the powder mixture for powder magnetic core according to Embodiment 3 of the present invention is changed. It is explanatory drawing, Comprising: (a) is a forming pressure of 800 MPa, (b) is a forming pressure of 1000 MPa, and (c) is a forming pressure of 1200 MPa.
  • a lubricant for example, a material in which ethylenebisamide is suspended in alcohol
  • a mold for compression molding outer diameter ⁇ 31.75 mm ⁇ inner diameter ⁇ 12.7 mm ⁇ height 5 mm.
  • the surface of the iron-based soft magnetic powder is coated with the iron-based soft magnetic powder E in which the phosphoric acid-based chemical conversion coating (lower layer) and the silicone resin coating (upper layer) are coated in this order on the mold.
  • a mixed powder composed of non-iron-based soft magnetic powder F was added, and the molding pressure was changed in the range of 800, 1000 and 1200 MPa at room temperature, and each was press-molded into a toroidal shape to obtain a molded body. Note that no lubricant is added to the mixed powder.
  • the raw powder mixing ratio is 0% by mass (that is, only the double-coated iron-based soft magnetic powder E), 3% by mass, 5% by mass, and 10% by mass. %, 20% by mass, 30% by mass, and 50% by mass.
  • the raw powder F contained in the mixed powder is molded in any case of F1 (raw powder coarse powder), F2 (raw powder fine powder), and F3 (raw powder total particle size). It can be seen that the density of the compact increases as the pressure increases. Therefore, as in the case of the second embodiment, the magnetic flux density is further improved as the molding pressure is increased, which suggests that the particle size dependency of the raw powder F is relatively small (details are shown in FIG. 14 described later). And FIG. 15).
  • FIG. 14 is a characteristic diagram (molding pressure 1200 MPa) showing the relationship between the raw powder mixing ratio and the magnetic flux density in the powder magnetic core (when the particle size of the raw powder F is changed) according to the embodiment.
  • the powder magnetic core for measuring the magnetic flux density was obtained by annealing the compact for compact density measurement (molding pressure: 1200 MPa) shown in FIG. 13C in nitrogen at a predetermined temperature (for example, 500 ° C., 30 minutes). We used what we did.
  • a DC BH tracer was used as in the case of the second embodiment.
  • the magnetic flux density was further improved as in the case of the second embodiment, which showed that the particle size dependence of the raw powder F was relatively small. (See FIG. 14). Moreover, as shown in FIG. 14, when the raw powder mixing ratio is at least 3% by mass or more, the effect of the present invention is more exhibited particularly in the case of F1 (raw coarse powder) and F3 (raw powder total particle size). It can be seen that the magnetic flux density is also improved compared to the level when the raw powder mixing ratio is 0 mass%.
  • FIG. 15 is an explanatory diagram for collectively explaining the relationship between the compact density and the magnetic flux density at the compacting pressure of 1200 MPa as described above. It can be seen from FIG. 15 that there is a substantially linear relationship between the compact density and the magnetic flux density, and the particle size dependence of the raw powder F is small.
  • FIG. 16 to 18 are characteristic diagrams showing the relationship between the raw powder mixing ratio and the iron loss in the dust core according to the present embodiment.
  • FIG. 16 is a characteristic diagram (forming pressure 1200 MPa, excitation magnetic field) showing the relationship between the raw powder mixing ratio and the iron loss in the powder magnetic core (when the particle size of the raw powder F is changed) according to the embodiment.
  • 0.1T, excitation frequency 10 kHz) (a) is raw powder F1
  • (b) is raw powder F2
  • (c) is raw powder F3
  • FIG. 17 shows the green compact according to the embodiment.
  • FIG. 17 shows the green compact according to the embodiment.
  • FIG. 6 is a characteristic diagram (molding pressure 1200 MPa, excitation magnetic field 0.2 T, excitation frequency 1 kHz) showing the relationship between the raw powder mixing ratio and iron loss in a magnetic core (when the particle size of raw powder F is changed), and (a) Is the raw powder F1, (b) is the raw powder F2, (c) is the raw powder F3, and FIG. 18 is the powder magnetic core according to the embodiment (when the particle size of the raw powder F is changed).
  • Characteristic diagram showing the relationship between raw powder mixing ratio and iron loss (molding pressure 1200 MPa, excitation magnetic field 0.2 T, excitation A frequency 5kHz), (a) is Namakona F1, (b) is Namakona F2, (c) is Namakona F3.
  • the iron-based soft magnetic powder used for the dust core (measurement sample) for measuring the iron loss is the same as in Examples 6 and 7, as detailed in Table 6 above.
  • the mixed powder is also the same as in Examples 6 and 7.
  • the raw powder mixing ratio in FIGS. 16 to 18 was also 0% by mass (that is, only the iron-based soft magnetic powder E double-coated), 3% by mass, as in Examples 6 and 7. The change was made to 5% by mass, 10% by mass, 20% by mass, 30% by mass, and 50% by mass.
  • the dust cores for measuring iron loss are all the same except that the above-described dust core for measuring magnetic flux density is different from the molding die for compression molding. That is, the mold of the powder magnetic core for measuring iron loss has an outer diameter of 45 mm, an inner diameter of 33 mm, and a height of 5 mm, as in the second embodiment. Further, in the measurement of iron loss, an AC BH analyzer was used as in the case of the second embodiment. Table 7 below collectively shows the measurement conditions and the specifications of the molding pressure (molding pressure) when the dust core was formed.
  • the predetermined iron loss ⁇ that is, the increase in iron loss with respect to the iron loss when the raw powder mixing ratio is 0% by mass is within about 5% ⁇ It turned out that it was suppressed enough. It can also be seen from FIGS. 16 to 18 that the iron loss is less dependent on the particle size of the raw powder F.
  • inorganic insulating films such as boric acid and sodium silicate, oxide-based insulating films such as SiO 2 and MgO, and the like can be appropriately selected and used as the insulating film. it can.
  • a heat resistant resin film besides a silicone resin film, a film made of a heat-resistant resin such as an imide resin or an engineering plastic resin can be appropriately selected and used.
  • the lubricant in addition to ethylene bisamide such as ethylene bislauric acid amide, it is possible to appropriately select and use a conventionally used lubricant during compression molding of a dust core such as a metal soap or a linear fatty acid amide. .

Abstract

One embodiment of the present invention relates to a powder mixture for a powder magnetic core, said powder mixture being characterized by: comprising an iron-based soft magnetic powder (A) that is coated with an insulating film and an iron-based soft magnetic powder (B) that is not coated with an insulating film; and by the mixture ratio of the iron-based soft magnetic powder (A) and the iron-based soft magnetic powder (B) satisfying formula (1) that is indicated below. The present invention makes it possible to achieve a powder mixture for a powder magnetic core that improves compressibility at the time of molding and that makes it possible to keep iron loss (hysteresis loss + eddy current loss) within a predetermined amount. Formula (1): 1 mass% ≤ [mass of iron-based soft magnetic powder (B)/(mass of iron-based soft magnetic powder (A) + mass of iron-based soft magnetic powder (B))] × 100 ≤ 5 mass%.

Description

圧粉磁心用混合粉末および圧粉磁心Mixed powder for dust core and dust core
　本発明は、成形時の圧縮性向上が図られるとともに、所定の鉄損（ヒステリシス損＋渦電流損）内に抑えることを可能にする圧粉磁心用混合粉末およびこの混合粉末を用いた圧粉磁心に関するものである。 The present invention improves the compressibility at the time of molding, and enables to suppress the powder within a predetermined iron loss (hysteresis loss + eddy current loss), and a powder using the mixed powder. It is about magnetic core.
　圧粉磁心は、リアクトルやモータなど交流で使用する機器の鉄心として使用される。この鉄心が交流（例えば、周波数が１～１０kHz）で励磁されると、鉄損（ヒステリシス損＋渦電流損）が発生する。特に、周波数が高くなるに伴って、鉄損に占める渦電流損の割合も高くなってくる。 圧 The dust core is used as an iron core for devices such as reactors and motors that are used in alternating current. When this iron core is excited with an alternating current (for example, a frequency of 1 to 10 kHz), iron loss (hysteresis loss + eddy current loss) occurs. In particular, as the frequency increases, the ratio of eddy current loss to iron loss also increases.
　上記渦電流損を低減させるために、古くは単純に圧粉磁心の原料となる軟磁性粉末粒子と樹脂粉末を混合し、軟磁性粉末粒子の表面に電気的絶縁層を形成するような技術が用いられていた（例えば、特許文献１）。 In order to reduce the eddy current loss, in the old days, there has been a technique in which soft magnetic powder particles that are simply used as a raw material for a powder magnetic core and resin powder are mixed to form an electrically insulating layer on the surface of the soft magnetic powder particles. (For example, patent document 1).
　さらに、軟磁性粉末粒子の表面に形成された電気的絶縁層の絶縁性を高めつつ圧粉体の密度の向上も狙って、軟磁性粉末粒子の表面に絶縁材料を被覆するような技術も開示されている（例えば、特許文献２～６）。 Furthermore, a technique for covering the surface of the soft magnetic powder particles with an insulating material is also disclosed with the aim of improving the density of the green compact while enhancing the insulation of the electrically insulating layer formed on the surface of the soft magnetic powder particles. (For example, Patent Documents 2 to 6).
日本国特開２００２－２８０２０９号公報Japanese Unexamined Patent Publication No. 2002-280209 日本国特開２００４－３１９７４９号公報Japanese Unexamined Patent Publication No. 2004-319749 日本国特許第４１８７２６６号公報Japanese Patent No. 4187266 日本国特開２００６－３０７３１２号公報Japanese Laid-Open Patent Publication No. 2006-307312 日本国特許第４０４４５９１号公報Japanese Patent No. 4044591 日本国特許第５０７８９３２号公報Japanese Patent No. 5078932
　しかしながら、上記特許文献１に開示された技術では、渦電流損を低減させるための電気的絶縁層形成に過剰な樹脂粉末が用いられ、そもそも成形圧が高い割には成形体の密度も低く（すなわち、圧縮性が低く）、磁気特性（透磁率や磁束密度）が中々向上しないという課題を有していた。 However, in the technique disclosed in Patent Document 1, excessive resin powder is used to form an electrical insulating layer for reducing eddy current loss, and the density of the molded body is low for a high molding pressure in the first place ( That is, there is a problem that the compressibility is low) and magnetic characteristics (permeability and magnetic flux density) are not improved moderately.
　また、上記特許文献２、特許文献５および特許文献６に開示された技術の場合は、上記特許文献１に開示された技術に比べると、軟磁性粉末粒子の表面に形成する電気的絶縁層としての有機系絶縁材料の使用量が低減する。よって、成形体の密度も多少向上し（すなわち、圧縮性も多少向上し）、磁気特性（透磁率や磁束密度）の改善が図られる。しかし、この有機系絶縁材料の厚さを制御し、均一に塗布するのは難しく、渦電流損を所定値以下にバラツキなく安定させるのが容易でないという課題を有していた。 Further, in the case of the techniques disclosed in Patent Document 2, Patent Document 5, and Patent Document 6, as compared with the technique disclosed in Patent Document 1, an electrical insulating layer formed on the surface of the soft magnetic powder particles is used. The amount of organic insulating material used is reduced. Therefore, the density of the molded body is also slightly improved (that is, the compressibility is also slightly improved), and the magnetic properties (permeability and magnetic flux density) are improved. However, it is difficult to control the thickness of the organic insulating material and apply it uniformly, and there is a problem that it is not easy to stabilize the eddy current loss to a predetermined value or less.
　また、上記特許文献３および特許文献４に開示された技術の場合は、軟磁性粉末粒子の表面に形成された電気的絶縁層が無機系絶縁材料であるため、成形時の金型にかかる負担が高いばかりか、原料粉末の圧縮性が低く、成形体としての所定密度を得るための成形圧の低減が困難であるという課題を有していた。 Further, in the case of the techniques disclosed in Patent Document 3 and Patent Document 4, since the electrically insulating layer formed on the surface of the soft magnetic powder particles is an inorganic insulating material, the load applied to the mold during molding is reduced. However, the raw material powder has a low compressibility, and it is difficult to reduce the molding pressure to obtain a predetermined density as a molded body.
　本発明の目的は、成形時の圧縮性向上が図られるとともに、所定の鉄損（ヒステリシス損＋渦電流損）内に抑えることを可能にする圧粉磁心用混合粉末およびこの混合粉末を用いた圧粉磁心を提供することを目的とする。 An object of the present invention is to use a mixed powder for a powder magnetic core, which can improve the compressibility during molding and can be suppressed within a predetermined iron loss (hysteresis loss + eddy current loss), and the mixed powder. The object is to provide a dust core.
　この目的を達成するために、第１発明に係る圧粉磁心用混合粉末は、
　絶縁被膜で被覆処理された鉄基軟磁性粉末Ａと絶縁被膜で被覆処理されていない鉄基軟磁性粉末Ｂとを含み、
　前記鉄基軟磁性粉末Ａと前記鉄基軟磁性粉末Ｂの混合割合が下記（１）式を満足することを特徴とする圧粉磁心用混合粉末である。
　１質量％≦［鉄基軟磁性粉末Ｂの質量／（鉄基軟磁性粉末Ａの質量＋鉄基軟磁性粉末Ｂの質量）］×１００≦５質量％　－－－（１） In order to achieve this object, the powder mixture for a powder magnetic core according to the first invention comprises:
Including iron-based soft magnetic powder A coated with an insulating coating and iron-based soft magnetic powder B not coated with an insulating coating,
A mixed powder for a dust core, wherein a mixing ratio of the iron-based soft magnetic powder A and the iron-based soft magnetic powder B satisfies the following formula (1).
1% by mass ≦ [mass of iron-based soft magnetic powder B / (mass of iron-based soft magnetic powder A + mass of iron-based soft magnetic powder B)] × 100 ≦ 5% by mass --- (1)
　第２発明に係る圧粉磁心用混合粉末は、
　６００μｍ以下の粒径で、かつ、７５μｍ未満の粒径の存在比率が２質量％以下である鉄基軟磁性粉末を用い、この鉄基軟磁性粉末が絶縁被膜で被覆処理された鉄基軟磁性粉末Ｃと絶縁被膜で被覆処理されていない鉄基軟磁性粉末Ｄとを含み、
　前記鉄基軟磁性粉末Ｃと前記鉄基軟磁性粉末Ｄの混合割合が下記（２）式を満足することを特徴とする圧粉磁心用混合粉末である。
　１質量％≦［鉄基軟磁性粉末Ｄの質量／（鉄基軟磁性粉末Ｃの質量＋鉄基軟磁性粉末Ｄの質量）］×１００≦３０質量％　－－－（２） The powder mixture for a dust core according to the second invention is:
An iron-based soft magnetic powder in which an iron-based soft magnetic powder having a particle size of 600 μm or less and a particle size of less than 75 μm is 2% by mass or less is coated with an insulating coating. Including powder C and iron-based soft magnetic powder D not coated with an insulating coating,
A mixed powder for a dust core, wherein a mixing ratio of the iron-based soft magnetic powder C and the iron-based soft magnetic powder D satisfies the following formula (2).
1 mass% ≦ [mass of iron-based soft magnetic powder D / (mass of iron-based soft magnetic powder C + mass of iron-based soft magnetic powder D)] × 100 ≦ 30 mass% −−− (2)
　第３発明に係る圧粉磁心用混合粉末は、第１または第２発明に係る圧粉磁心用混合粉末において、絶縁被膜は、少なくとも無機系絶縁被膜であることを特徴とする。 The powder mixture for powder magnetic core according to the third invention is the powder mixture for powder magnetic core according to the first or second invention, wherein the insulating coating is at least an inorganic insulating coating.
　第４発明に係る圧粉磁心用混合粉末は、第１～第３のいずれか１つの発明に係る圧粉磁心用混合粉末において、前記圧粉磁心用混合粉末に潤滑剤が混合されていることを特徴とする。 The powder mixture for powder magnetic core according to the fourth invention is the powder mixture for powder magnetic core according to any one of the first to third inventions, wherein a lubricant is mixed in the powder mixture for powder magnetic core. It is characterized by.
　第５発明に係る圧粉磁心用混合粉末は、
　６００μｍ以下の粒径の鉄基軟磁性粉末を用い、この鉄基軟磁性粉末の表面に無機系絶縁被膜と耐熱性樹脂被膜がこの順で被覆処理された鉄基軟磁性粉末Ｅと無機系絶縁被膜と耐熱性樹脂被膜で被覆処理されていない鉄基軟磁性粉末Ｆとを含み、
　前記鉄基軟磁性粉末Ｅと前記鉄基軟磁性粉末Ｆの混合割合が下記（３）式を満足することを特徴とする圧粉磁心用混合粉末である。
　３質量％≦［鉄基軟磁性粉末Ｆの質量／（鉄基軟磁性粉末Ｅの質量＋鉄基軟磁性粉末Ｆ
の質量）］×１００≦１０質量％　－－－（３） The mixed powder for a powder magnetic core according to the fifth invention is
An iron-based soft magnetic powder having a particle diameter of 600 μm or less is used, and an iron-based soft magnetic powder E in which an inorganic insulating coating and a heat-resistant resin coating are coated in this order on the surface of the iron-based soft magnetic powder and the inorganic insulating And iron-based soft magnetic powder F not coated with a heat-resistant resin film,
A mixed powder for a dust core, wherein a mixing ratio of the iron-based soft magnetic powder E and the iron-based soft magnetic powder F satisfies the following expression (3).
3% by mass ≦ [mass of iron-based soft magnetic powder F / (mass of iron-based soft magnetic powder E + iron-based soft magnetic powder F
Mass)] × 100 ≦ 10 mass% --- (3)
　第６発明に係る圧粉磁心用混合粉末は、第５発明に係る圧粉磁心用混合粉末において、圧縮成形を行う成形型の内壁面に潤滑剤が塗布され、前記圧粉磁心用混合粉末中には潤滑剤が添加されていないことを特徴とする。 The powder mixture for powder magnetic core according to the sixth invention is the powder mixture for powder magnetic core according to the fifth invention, wherein a lubricant is applied to the inner wall surface of a mold for compression molding, and the powder mixture for powder magnetic core Is characterized in that no lubricant is added.
　第７発明に係る圧粉磁心は、第１～第６発明のいずれか１つの発明に係る圧粉磁心用混合粉末を圧縮成形し、この圧縮成形により得られた成形体が所定温度で焼鈍されていることを特徴とする圧粉磁心である。 A powder magnetic core according to a seventh aspect of the present invention is obtained by compression molding the powder mixture for a powder magnetic core according to any one of the first to sixth aspects, and the molded body obtained by the compression molding is annealed at a predetermined temperature. It is a dust core characterized by
　以上のように、第１発明に係る圧粉磁心用混合粉末は、
　絶縁被膜で被覆処理された鉄基軟磁性粉末Ａと絶縁被膜で被覆処理されていない鉄基軟磁性粉末Ｂとを含み、
　前記鉄基軟磁性粉末Ａと前記鉄基軟磁性粉末Ｂの混合割合が下記（１）式を満足することを特徴とする圧粉磁心用混合粉末である。
　１質量％≦［鉄基軟磁性粉末Ｂの質量／（鉄基軟磁性粉末Ａの質量＋鉄基軟磁性粉末Ｂの質量）］×１００≦５質量％　－－－（１） As described above, the powder mixture for a dust core according to the first invention is
Including iron-based soft magnetic powder A coated with an insulating coating and iron-based soft magnetic powder B not coated with an insulating coating,
A mixed powder for a dust core, wherein a mixing ratio of the iron-based soft magnetic powder A and the iron-based soft magnetic powder B satisfies the following formula (1).
1% by mass ≦ [mass of iron-based soft magnetic powder B / (mass of iron-based soft magnetic powder A + mass of iron-based soft magnetic powder B)] × 100 ≦ 5% by mass --- (1)
　また、第２発明に係る圧粉磁心用混合粉末は、
　６００μｍ以下の粒径で、かつ、７５μｍ未満の粒径の存在比率が２質量％以下である鉄基軟磁性粉末を用い、この鉄基軟磁性粉末が絶縁被膜で被覆処理された鉄基軟磁性粉末Ｃと絶縁被膜で被覆処理されていない鉄基軟磁性粉末Ｄとを含み、
　前記鉄基軟磁性粉末Ｃと前記鉄基軟磁性粉末Ｄの混合割合が下記（２）式を満足することを特徴とする圧粉磁心用混合粉末である。
　１質量％≦［鉄基軟磁性粉末Ｄの質量／（鉄基軟磁性粉末Ｃの質量＋鉄基軟磁性粉末Ｄの質量）］×１００≦３０質量％　－－－（２） Further, the powder mixture for a dust core according to the second invention is:
An iron-based soft magnetic powder in which an iron-based soft magnetic powder having a particle size of 600 μm or less and a particle size of less than 75 μm is 2% by mass or less is coated with an insulating coating. Including powder C and iron-based soft magnetic powder D not coated with an insulating coating,
A mixed powder for a dust core, wherein a mixing ratio of the iron-based soft magnetic powder C and the iron-based soft magnetic powder D satisfies the following formula (2).
1 mass% ≦ [mass of iron-based soft magnetic powder D / (mass of iron-based soft magnetic powder C + mass of iron-based soft magnetic powder D)] × 100 ≦ 30 mass% −−− (2)
　また、第５発明に係る圧粉磁心用混合粉末は、
　６００μｍ以下の粒径の鉄基軟磁性粉末を用い、この鉄基軟磁性粉末の表面に無機系絶縁被膜と耐熱性樹脂被膜がこの順で被覆処理された鉄基軟磁性粉末Ｅと無機系絶縁被膜と耐熱性樹脂被膜で被覆処理されていない鉄基軟磁性粉末Ｆとを含み、
　前記鉄基軟磁性粉末Ｅと前記鉄基軟磁性粉末Ｆの混合割合が下記（３）式を満足することを特徴とする圧粉磁心用混合粉末である。
　３質量％≦［鉄基軟磁性粉末Ｆの質量／（鉄基軟磁性粉末Ｅの質量＋鉄基軟磁性粉末Ｆの質量）］×１００≦１０質量％　－－－（３） Moreover, the powder mixture for powder magnetic cores according to the fifth invention is
An iron-based soft magnetic powder having a particle diameter of 600 μm or less is used, and an iron-based soft magnetic powder E in which an inorganic insulating coating and a heat-resistant resin coating are coated in this order on the surface of the iron-based soft magnetic powder and the inorganic insulating And iron-based soft magnetic powder F not coated with a heat-resistant resin film,
A mixed powder for a dust core, wherein a mixing ratio of the iron-based soft magnetic powder E and the iron-based soft magnetic powder F satisfies the following expression (3).
3% by mass ≦ [mass of iron-based soft magnetic powder F / (mass of iron-based soft magnetic powder E + mass of iron-based soft magnetic powder F)] × 100 ≦ 10% by mass --- (3)
　これらにより、成形時の圧縮性向上が図られるとともに、所定の鉄損（ヒステリシス損＋渦電流損）内に抑えることを可能にする圧粉磁心用混合粉末を実現できる。 Thus, it is possible to improve the compressibility at the time of molding and to realize a mixed powder for a dust core that can be suppressed within a predetermined iron loss (hysteresis loss + eddy current loss).
　また、本発明に係る圧粉磁心は、上記圧粉磁心用混合粉末を圧縮成形し、この圧縮成形により得られた成形体が所定温度で焼鈍されていることを特徴とする。 The powder magnetic core according to the present invention is characterized in that the powder mixture for powder magnetic core is compression molded, and a molded body obtained by the compression molding is annealed at a predetermined temperature.
　これにより、所定の鉄損（ヒステリシス損＋渦電流損）内に抑えることを可能にする。 This makes it possible to suppress within a predetermined iron loss (hysteresis loss + eddy current loss).
図１は、本発明の実施形態１に係る圧粉磁心用混合粉末の生粉混合割合を変化させた場合における、成形圧と成形体密度の関係を説明するための説明図である。FIG. 1 is an explanatory diagram for explaining a relationship between a molding pressure and a compact density when the raw powder mixing ratio of the powder mixture for a powder magnetic core according to the first embodiment of the present invention is changed. 図２は、本発明の実施形態１に係る圧粉磁心における、生粉混合割合と鉄損の関係を示す特性図（成形圧力８００ＭＰａ、励磁磁界０．１Ｔ、励磁周波数１０ｋＨｚ）である。FIG. 2 is a characteristic diagram (forming pressure 800 MPa, excitation magnetic field 0.1 T, excitation frequency 10 kHz) showing the relationship between the raw powder mixing ratio and the iron loss in the powder magnetic core according to the first embodiment of the present invention. 図３は、本発明の実施形態１に係る圧粉磁心における、生粉混合割合と鉄損の関係を示す特性図（成形圧力１２００ＭＰａ、励磁磁界０．１Ｔ、励磁周波数１０ｋＨｚ）である。FIG. 3 is a characteristic diagram (forming pressure 1200 MPa, excitation magnetic field 0.1 T, excitation frequency 10 kHz) showing the relationship between the raw powder mixing ratio and the iron loss in the powder magnetic core according to Embodiment 1 of the present invention. 図４は、本発明の実施形態１に係る圧粉磁心における、生粉混合割合と鉄損の関係を示す特性図（成形圧力８００ＭＰａ、励磁磁界０．２Ｔ、励磁周波数１ｋＨｚ）である。FIG. 4 is a characteristic diagram (forming pressure 800 MPa, excitation magnetic field 0.2 T, excitation frequency 1 kHz) showing the relationship between the raw powder mixing ratio and the iron loss in the powder magnetic core according to Embodiment 1 of the present invention. 図５は、本発明の実施形態１に係る圧粉磁心における、生粉混合割合と鉄損の関係を示す特性図（成形圧力１２００ＭＰａ、励磁磁界０．２Ｔ、励磁周波数１ｋＨｚ）である。FIG. 5 is a characteristic diagram (forming pressure 1200 MPa, excitation magnetic field 0.2 T, excitation frequency 1 kHz) showing the relationship between the raw powder mixing ratio and the iron loss in the powder magnetic core according to Embodiment 1 of the present invention. 図６は、本発明の実施形態１に係る圧粉磁心における、生粉混合割合と鉄損の関係を示す特性図（成形圧力８００ＭＰａ、励磁磁界０．２Ｔ、励磁周波数５ｋＨｚ）である。FIG. 6 is a characteristic diagram (forming pressure 800 MPa, excitation magnetic field 0.2 T, excitation frequency 5 kHz) showing the relationship between the raw powder mixing ratio and the iron loss in the powder magnetic core according to the first embodiment of the present invention. 図７は、本発明の実施形態１に係る圧粉磁心における、生粉混合割合と鉄損の関係を示す特性図（成形圧力１２００ＭＰａ、励磁磁界０．２Ｔ、励磁周波数５ｋＨｚ）である。FIG. 7 is a characteristic diagram (forming pressure 1200 MPa, excitation magnetic field 0.2 T, excitation frequency 5 kHz) showing the relationship between the raw powder mixing ratio and the iron loss in the powder magnetic core according to the first embodiment of the present invention. 図８は、本発明の実施形態２に係る鉄基軟磁性粉末Ｄにおける、成形圧と成形体密度の関係を説明するための説明図である。FIG. 8 is an explanatory diagram for explaining the relationship between the molding pressure and the compact density in the iron-based soft magnetic powder D according to the second embodiment of the present invention. 図９は、本発明の実施形態２に係る圧粉磁心における、生粉混合割合と鉄損の関係を示す特性図（成形圧力９００ＭＰａ、励磁磁界０．１Ｔ、励磁周波数１０ｋＨｚ）である。FIG. 9 is a characteristic diagram (forming pressure 900 MPa, excitation magnetic field 0.1 T, excitation frequency 10 kHz) showing the relationship between the raw powder mixing ratio and the iron loss in the powder magnetic core according to the second embodiment of the present invention. 図１０は、本発明の実施形態２に係る圧粉磁心における、生粉混合割合と鉄損の関係を示す特性図（成形圧力９００ＭＰａ、励磁磁界０．２Ｔ、励磁周波数１ｋＨｚ）である。FIG. 10 is a characteristic diagram (forming pressure 900 MPa, excitation magnetic field 0.2 T, excitation frequency 1 kHz) showing the relationship between the raw powder mixing ratio and the iron loss in the powder magnetic core according to the second embodiment of the present invention. 図１１は、本発明の実施形態２に係る圧粉磁心における、生粉混合割合と鉄損の関係を示す特性図（成形圧力９００ＭＰａ、励磁磁界０．２Ｔ、励磁周波数５ｋＨｚ）である。FIG. 11 is a characteristic diagram (forming pressure 900 MPa, excitation magnetic field 0.2 T, excitation frequency 5 kHz) showing the relationship between the raw powder mixing ratio and the iron loss in the powder magnetic core according to the second embodiment of the present invention. 図１２は、本発明の実施形態２に係る圧粉磁心用混合粉末の生粉混合割合を変化させた場合における、成形体密度と磁束密度の関係を説明するための説明図である。FIG. 12 is an explanatory diagram for explaining the relationship between the compact density and the magnetic flux density when the raw powder mixing ratio of the powder mixture for powder magnetic core according to the second embodiment of the present invention is changed. 図１３は、本発明の実施形態３に係る圧粉磁心用混合粉末の含有させる生粉Ｆの粒度を変化させた場合における、生粉混合割合と成形体密度の関係を説明するための説明図であって、（ａ）は成形圧８００ＭＰａ、（ｂ）は成形圧１０００ＭＰａ、（ｃ）は成形圧１２００ＭＰａである。FIG. 13 is an explanatory diagram for explaining the relationship between the raw powder mixing ratio and the compact density when the particle size of the raw powder F contained in the powder mixture for powder magnetic core according to Embodiment 3 of the present invention is changed. (A) is a molding pressure of 800 MPa, (b) is a molding pressure of 1000 MPa, and (c) is a molding pressure of 1200 MPa. 図１４は、本発明の実施形態３に係る圧粉磁心（生粉Ｆの粒度を変化させた場合）における、生粉混合割合と磁束密度の関係を示す特性図（成形圧力１２００ＭＰａ）である。FIG. 14 is a characteristic diagram (molding pressure 1200 MPa) showing the relationship between the raw powder mixing ratio and the magnetic flux density in the powder magnetic core (when the particle size of the raw powder F is changed) according to Embodiment 3 of the present invention. 図１５は、本発明の実施形態３に係る圧粉磁心（生粉Ｆの粒度を変化させた場合）における、成形体密度と磁束密度の関係を説明するための説明図（成形圧力１２００ＭＰａ）である。FIG. 15 is an explanatory diagram (molding pressure 1200 MPa) for explaining the relationship between the compact density and the magnetic flux density in the dust core according to the third embodiment of the present invention (when the particle size of the raw powder F is changed). is there. 図１６は、本発明の実施形態３に係る圧粉磁心（生粉Ｆの粒度を変化させた場合）における、生粉混合割合と鉄損の関係を示す特性図（成形圧力１２００ＭＰａ、励磁磁界０．１Ｔ、励磁周波数１０ｋＨｚ）であって、（ａ）は生粉Ｆ１、（ｂ）は生粉Ｆ２、（ｃ）は生粉Ｆ３である。FIG. 16 is a characteristic diagram (forming pressure 1200 MPa, excitation magnetic field 0) showing the relationship between the raw powder mixing ratio and the iron loss in the powder magnetic core (when the particle size of the raw powder F is changed) according to Embodiment 3 of the present invention. (1T, excitation frequency 10 kHz), (a) is raw powder F1, (b) is raw powder F2, and (c) is raw powder F3. 図１７は、本発明の実施形態３に係る圧粉磁心（生粉Ｆの粒度を変化させた場合）における、生粉混合割合と鉄損の関係を示す特性図（成形圧力１２００ＭＰａ、励磁磁界０．２Ｔ、励磁周波数１ｋＨｚ）であって、（ａ）は生粉Ｆ１、（ｂ）は生粉Ｆ２、（ｃ）は生粉Ｆ３である。FIG. 17 is a characteristic diagram (forming pressure 1200 MPa, excitation magnetic field 0) showing the relationship between the raw powder mixing ratio and the iron loss in the powder magnetic core (when the particle size of the raw powder F is changed) according to Embodiment 3 of the present invention. (2T, excitation frequency 1 kHz), (a) is raw powder F1, (b) is raw powder F2, and (c) is raw powder F3. 図１８は、本発明の実施形態３に係る圧粉磁心（生粉Ｆの粒度を変化させた場合）における、生粉混合割合と鉄損の関係を示す特性図（成形圧力１２００ＭＰａ、励磁磁界０．２Ｔ、励磁周波数５ｋＨｚ）であって、（ａ）は生粉Ｆ１、（ｂ）は生粉Ｆ２、（ｃ）は生粉Ｆ３である。FIG. 18 is a characteristic diagram (forming pressure 1200 MPa, excitation magnetic field 0) showing the relationship between the raw powder mixing ratio and the iron loss in the powder magnetic core (when the particle size of the raw powder F is changed) according to Embodiment 3 of the present invention. (2T, excitation frequency 5 kHz), (a) is raw powder F1, (b) is raw powder F2, and (c) is raw powder F3.
（実施形態１）
　以下、本発明の実施形態１に係る圧粉磁心用混合粉末およびこの混合粉末を用いた圧粉磁心の構成について、実施形態を例示しつつ、詳細に説明する。 (Embodiment 1)
Hereinafter, the mixed powder for a powder magnetic core according to the first embodiment of the present invention and the structure of the powder magnetic core using the mixed powder will be described in detail while illustrating the embodiment.
　本発明の実施形態１に係る圧粉磁心用混合粉末（すなわち、第１発明に係る圧粉磁心用混合粉末）は、絶縁被膜で被覆処理された鉄基軟磁性粉末Ａと絶縁被膜で被覆処理されていない鉄基軟磁性粉末Ｂとを含み、
　前記鉄基軟磁性粉末Ａと前記鉄基軟磁性粉末Ｂの混合割合が下記（１）式を満足することを特徴とする。
　１質量％≦［鉄基軟磁性粉末Ｂの質量／（鉄基軟磁性粉末Ａの質量＋鉄基軟磁性粉末Ｂの質量）］×１００≦５質量％　－－－（１） The powder mixture for powder magnetic core according to Embodiment 1 of the present invention (that is, the powder mixture for powder magnetic core according to the first invention) is coated with an iron-based soft magnetic powder A coated with an insulation coating and an insulation coating. Iron-based soft magnetic powder B that has not been made,
The mixing ratio of the iron-based soft magnetic powder A and the iron-based soft magnetic powder B satisfies the following formula (1).
1% by mass ≦ [mass of iron-based soft magnetic powder B / (mass of iron-based soft magnetic powder A + mass of iron-based soft magnetic powder B)] × 100 ≦ 5% by mass --- (1)
　上記圧粉磁心用混合粉末を用いた場合、圧粉磁心としての成形体に成形する際の圧縮性が向上する｛例えば、従来の場合（無機系絶縁被膜で被覆処理された鉄基軟磁性粉末Ａのみから構成された場合）と同一の成形圧力（以下、成形圧と称する場合もある）を採用しながらも、従来の場合に比して成形体密度が向上する｝。よって、透磁率や磁束密度が従来の場合に比して向上する。また、上記圧粉磁心用混合粉末を用いたならば、成形体に成形する際の圧縮性を向上させることが可能であるにも拘らず、圧粉磁心において所定の鉄損｛ヒステリシス損（以下、ヒス損と称する場合もある）＋渦電流損（以下、渦損と称する場合もある）｝内｛例えば、無機系絶縁被膜で被覆処理された鉄基軟磁性粉末Ａのみから構成された場合（上記混合割合（以下、生粉混合割合と称する場合もある）が０質量％の場合）の鉄損に対して５％以内の増加｝に抑えることが可能となる。 When the above mixed powder for a powder magnetic core is used, the compressibility at the time of forming into a compact as a powder magnetic core is improved {for example, in the conventional case (iron-based soft magnetic powder coated with an inorganic insulating coating) The molding density is improved as compared with the conventional case while employing the same molding pressure (hereinafter sometimes referred to as molding pressure) as in the case of only A). Therefore, the magnetic permeability and magnetic flux density are improved as compared with the conventional case. In addition, if the powder mixture for powder magnetic core is used, a predetermined iron loss {hysteresis loss (hereinafter referred to as “loss loss”) in the powder magnetic core can be improved even though it is possible to improve the compressibility at the time of forming into a compact. ), And eddy current loss (hereinafter also referred to as eddy loss)} inside {for example, when composed only of iron-based soft magnetic powder A coated with an inorganic insulating coating It is possible to suppress an increase within 5% with respect to the iron loss of the above mixing ratio (hereinafter also referred to as raw powder mixing ratio is 0% by mass).
　本発明において使用される鉄基軟磁性粉末は、強磁性体の金属粉末であり、具体例としては、純鉄粉、鉄基合金粉末（Ｆｅ－Ａ１合金、Ｆｅ－Ｓｉ合金、センダスト、パーマロイなど）およびアモルファス粉末等が挙げられる。こうした軟磁性粉末は、例えば、アトマイズ法によって微粒子とした後還元し、その後粉砕すること等によって製造できる。本発明においては、原理的に通常の粉末冶金に用いられる粒度であれば、粒度分布に依存せずその作用効果を発揮する。ただし、所定の鉄損に抑えながら、同時に成形体に成形する際の圧縮性を向上させることを意図しているため、粒度の大きな成分（例えば、２５０μｍ以上６００μｍ以下）を通常より多少多く含んだ鉄基軟磁性粉末がより好ましい（詳細は、下記表１参照）。なお、上記鉄基軟磁性粉末は、日本粉末冶金工業会で規定される「金属粉のふるい分析試験方法」（ＪＰＭＡ　　ＰＯ２－１９９２）に準拠して、まず目開き６００μｍの篩を用いて篩い分けした後、さらに下記表１に示す粒度に対応する目開き２５０μｍから４５μｍの篩を用いて順次篩い分けした。 The iron-based soft magnetic powder used in the present invention is a ferromagnetic metal powder. Specific examples thereof include pure iron powder, iron-based alloy powder (Fe—A1 alloy, Fe—Si alloy, Sendust, Permalloy, etc.). ) And amorphous powder. Such a soft magnetic powder can be produced, for example, by reducing it into fine particles by the atomizing method, reducing it, and then pulverizing it. In the present invention, in principle, any particle size used in ordinary powder metallurgy exhibits its effects without depending on the particle size distribution. However, since it is intended to improve the compressibility when molding into a molded body at the same time while suppressing to a predetermined iron loss, a component having a large particle size (for example, 250 μm or more and 600 μm or less) is included a little more than usual. An iron-based soft magnetic powder is more preferred (see Table 1 below for details). The iron-based soft magnetic powder is first sieved using a sieve having an aperture of 600 μm in accordance with “Metal Powder Sieve Analysis Test Method” (JPMA PO2-1992) prescribed by the Japan Powder Metallurgy Industry Association. After that, sieving was sequentially performed using a sieve having an opening of 250 μm to 45 μm corresponding to the particle size shown in Table 1 below.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　また、本発明における鉄基軟磁性粉末Ｂとは、上記鉄基軟磁性粉末の表面を、後述するような絶縁被膜で被覆処理してないものを指して言う。これを称して、生粉とも言う。 Further, the iron-based soft magnetic powder B in the present invention refers to a material in which the surface of the iron-based soft magnetic powder is not coated with an insulating film as described later. This is also called raw powder.
　また、本発明における鉄基軟磁性粉末Ａとは、上記鉄基軟磁性粉末の表面を、下記のような絶縁被膜で被覆処理したものを指して言う。また、本発明における上記絶縁被膜は、少なくとも無機系絶縁被膜であることが好ましい。この無機系絶縁被膜としてのリン酸系化成被膜は、上記鉄基軟磁性粉末に対する濡れ性が良く、この被膜で鉄基軟磁性粉末の表面を均一に被覆することが可能である点からより好ましい。 Further, the iron-based soft magnetic powder A in the present invention refers to a material obtained by coating the surface of the iron-based soft magnetic powder with the following insulating coating. Moreover, it is preferable that the said insulating film in this invention is an inorganic type insulating film at least. The phosphoric acid-based chemical conversion coating as the inorganic insulating coating is more preferable because it has good wettability with respect to the iron-based soft magnetic powder and can uniformly coat the surface of the iron-based soft magnetic powder with this coating. .
　上述したリン酸系化成被膜の形成には、リン酸系化成被膜用処理液として、水：５０部（質量部を意味する。以下同じ。）、ＮａＨ2ＰＯ4：３０部、Ｈ3ＰＯ4：１０部、（ＮＨ2ＯＨ）2・Ｈ2ＳＯ4：１０部、Ｃｏ3（ＰＯ4）2：１０部を混合して、更に水で２０倍に希釈した処理液を用いた。また、上記鉄基軟磁性粉末１００部に対して、この処理液を５部混合し、大気中２００℃で乾燥させた。このリン酸系化成被膜の厚みは、１０～１００ｎｍとなる。 In the formation of the phosphoric acid-based chemical conversion film, water: 50 parts (meaning parts by mass; the same applies hereinafter), NaH 2 PO 4 : 30 parts, H 3 PO 4 as the phosphoric acid-based chemical film treatment solution. : 10 parts, (NH 2 OH) 2 · H 2 SO 4 : 10 parts, Co 3 (PO 4 ) 2 : 10 parts were mixed, and a treatment solution diluted 20 times with water was used. Further, 5 parts of this treatment liquid was mixed with 100 parts of the iron-based soft magnetic powder and dried at 200 ° C. in the atmosphere. The thickness of the phosphoric acid-based chemical conversion film is 10 to 100 nm.
（本発明の実施形態１に係る圧粉磁心用混合粉末の成形圧と成形体密度の関係）
　図１は、本発明の実施形態１に係る圧粉磁心用混合粉末の生粉混合割合を変化させた場合における、成形圧と成形体密度の関係を説明するための説明図である。 (Relationship between molding pressure and compact density of powder mixture for powder magnetic core according to Embodiment 1 of the present invention)
FIG. 1 is an explanatory diagram for explaining a relationship between a molding pressure and a compact density when the raw powder mixing ratio of the powder mixture for a powder magnetic core according to the first embodiment of the present invention is changed.
　図１において、成形体を形成する圧粉磁心用混合粉末｛鉄基軟磁性粉末Ａと鉄基軟磁性粉末Ｂ（生粉）の混合粉末｝は、鉄基軟磁性粉末として純鉄粉を用いている。また、この使用する純鉄粉の粒度分布は、上述した表１に示す通りである。また、鉄基軟磁性粉末Ａとして、純鉄粉の表面に被覆処理した絶縁被膜は、上述したリン酸系化成被膜である。 In FIG. 1, the mixed powder for the powder magnetic core {mixed powder of iron-based soft magnetic powder A and iron-based soft magnetic powder B (raw powder)} that forms a compact uses pure iron powder as the iron-based soft magnetic powder. ing. Moreover, the particle size distribution of the pure iron powder used is as shown in Table 1 above. Moreover, the insulating coating which coat | covered the surface of the pure iron powder as the iron base soft magnetic powder A is the phosphoric acid type | system | group chemical conversion film mentioned above.
　上記圧粉磁心用混合粉末に潤滑剤としてのステアリン酸アミドを０．３質量％添加した後、金型（外径φ４５ｍｍ×内径φ３３ｍｍ×高さ５ｍｍ）内に入れ、室温下で成形圧を８００、１０００および１２００ＭＰａの範囲で変化させ、それぞれトロイダル形状にプレス成形し成形体を得た。この成形体を所定温度（例えば、３５０℃、３０分）で大気中焼鈍し、圧粉磁心とする。この圧粉磁心用混合粉末の生粉混合割合は、図１に示すように、各成形圧とも、０質量％｛すなわち、鉄基軟磁性粉末Ａ（リン酸系化成被膜で被覆処理した純鉄粉）のみ｝、１質量％、２質量％、３質量％、４質量％、５質量％、１０質量％、２０質量％および鉄基軟磁性粉末Ｂ｛すなわち、生粉（リン酸系化成被膜で被覆処理されてない純鉄粉）のみ｝である。なお、ここで生粉混合割合とは、［鉄基軟磁性粉末Ｂの質量／（鉄基軟磁性粉末Ａの質量＋鉄基軟磁性粉末Ｂの質量）］×１００と定義される。 After adding 0.3% by mass of stearamide as a lubricant to the powder mixture for powder magnetic core, it is put in a mold (outside diameter φ45 mm × inside diameter φ33 mm × height 5 mm), and the molding pressure is 800 at room temperature. , 1000 and 1200 MPa, and each was press-molded into a toroidal shape to obtain a molded body. This molded body is annealed in the atmosphere at a predetermined temperature (for example, 350 ° C., 30 minutes) to obtain a dust core. As shown in FIG. 1, the raw powder mixing ratio of this powder mixture for powder magnetic core is 0% by mass for each molding pressure {that is, iron-based soft magnetic powder A (pure iron coated with a phosphate chemical conversion coating). Only) 1% by mass, 2% by mass, 3% by mass, 4% by mass, 5% by mass, 10% by mass, 20% by mass and iron-based soft magnetic powder B {ie, raw powder (phosphoric acid-based chemical conversion coating) Only pure iron powder that is not coated with a). Here, the raw powder mixing ratio is defined as [mass of iron-based soft magnetic powder B / (mass of iron-based soft magnetic powder A + mass of iron-based soft magnetic powder B)] × 100.
　図１において、いずれの成形圧の場合も、生粉混合割合が高い程、成形体密度が高くなる。すなわち、生粉混合割合が高い程、成形時の圧縮性が向上することを示している。言い換えるならば、本発明は、所定の成形体密度を得るために、低い成形圧で済むことを示している。したがって、低い成形圧でも、従来に比して透磁率や磁束密度が向上するため、その技術的な意義は、非常に大きい。 In FIG. 1, in any of the molding pressures, the higher the raw powder mixing ratio, the higher the compact density. That is, the higher the raw powder mixing ratio, the better the compressibility during molding. In other words, the present invention shows that a low molding pressure is sufficient to obtain a predetermined molded body density. Therefore, even at a low molding pressure, the magnetic permeability and the magnetic flux density are improved as compared with the conventional one, and the technical significance thereof is very large.
　よって、成形体に成形する際の圧縮性を向上させることが可能でありながらも（図１参照）、圧粉磁心において所定の鉄損｛ヒステリシス損（以下、ヒス損と称する場合もある）＋渦電流損（以下、渦損と称する場合もある）｝内（例えば、無機系絶縁被膜で被覆処理された鉄基軟磁性粉末Ａのみから構成された場合の鉄損に対して５％以内の増加）に抑えることが可能な生粉混合割合が如何なる範囲にあるのか確証する必要がある。これについて、以下の実施例２で詳述する。 Therefore, while it is possible to improve the compressibility at the time of molding into a molded body (see FIG. 1), a predetermined iron loss {hysteresis loss (hereinafter sometimes referred to as hiss loss) in the dust core + Eddy current loss (hereinafter also referred to as eddy loss)} (for example, within 5% of iron loss when composed only of iron-based soft magnetic powder A coated with an inorganic insulating coating) It is necessary to confirm the range of the raw powder mixing ratio that can be suppressed to an increase). This will be described in detail in Example 2 below.
（生粉混合割合と鉄損の関係）
　図２～図７は、本実施の形態に係る圧粉磁心における、生粉混合割合と鉄損の関係を示す特性図である。鉄損を測定する圧粉磁心（測定試料）は、上記実施例１に詳述したものを使用する。なお、鉄損の測定には、交流Ｂ－Ｈアナライザーを用いた。また、測定条件および圧粉磁心を形成した際の成形圧力（成形圧）の各諸元を下記表２にまとめて示す。 (Relationship between raw powder mixing ratio and iron loss)
2 to 7 are characteristic diagrams showing the relationship between the raw powder mixing ratio and the iron loss in the powder magnetic core according to the present embodiment. As the dust core (measurement sample) for measuring the iron loss, the one detailed in Example 1 is used. An AC BH analyzer was used to measure the iron loss. Table 2 below collectively shows the measurement conditions and the specifications of the molding pressure (molding pressure) when the dust core was formed.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　図２～図７のいずれの場合も、生粉混合割合が１質量％～５質量％の範囲においては、生粉混合割合が０質量％｛すなわち、鉄基軟磁性粉末Ａ（リン酸系化成被膜で被覆処理した純鉄粉）のみ｝における鉄損に対して５％以内の増加に抑えられていることが判明した。 2 to 7, in the case where the raw powder mixing ratio is in the range of 1% by mass to 5% by mass, the raw powder mixing ratio is 0% by mass {that is, iron-based soft magnetic powder A (phosphate-based chemical conversion). It was proved that the increase was within 5% of the iron loss in only the pure iron powder coated with the coating.
　このように、絶縁被膜で被覆処理された鉄基軟磁性粉末Ａと絶縁被膜で被覆処理されていない鉄基軟磁性粉末Ｂとを含み、前記鉄基軟磁性粉末Ａと前記鉄基軟磁性粉末Ｂの混合割合が下記（１）式を満足する圧粉磁心用混合粉末を用いた場合、成形時の圧縮性向上が図られるとともに、所定の鉄損（ヒステリシス損＋渦電流損）内に抑えることを可能にしたのは、以下の理由が考えられるものと推察している。
　１質量％≦［鉄基軟磁性粉末Ｂの質量／（鉄基軟磁性粉末Ａの質量＋鉄基軟磁性粉末Ｂの質量）］×１００≦５質量％　－－－（１） As described above, the iron-based soft magnetic powder A coated with the insulating coating and the iron-based soft magnetic powder B not coated with the insulating coating are included, and the iron-based soft magnetic powder A and the iron-based soft magnetic powder B. When a mixed powder for a powder magnetic core in which the mixing ratio of B satisfies the following formula (1) is used, the compressibility at the time of molding is improved, and it is suppressed within a predetermined iron loss (hysteresis loss + eddy current loss). It is speculated that the following reasons can be considered to make this possible.
1% by mass ≦ [mass of iron-based soft magnetic powder B / (mass of iron-based soft magnetic powder A + mass of iron-based soft magnetic powder B)] × 100 ≦ 5% by mass --- (1)
　上記作用効果を奏することになったのは、絶縁被膜で被覆処理されていない鉄基軟磁性粉末Ｂの周囲を絶縁被膜で被覆処理された鉄基軟磁性粉末Ａが適当に取り囲むような構造を呈していることに起因していると推察している。すなわち、「変形性が良い鉄基軟磁性粉末Ｂの存在による成形時の圧縮性向上効果」と「鉄基軟磁性粉末Ｂ同士の適切な分離性確保の効果」が相俟って齎されたものと推察している。 The above-mentioned effects were achieved because the iron-based soft magnetic powder A coated with the insulating coating appropriately surrounds the iron-based soft magnetic powder B not coated with the insulating coating. It is assumed that it is caused by presenting. That is, “the effect of improving the compressibility at the time of molding due to the presence of the iron-based soft magnetic powder B having good deformability” and “the effect of ensuring appropriate separability between the iron-based soft magnetic powders B” were confounded together. I guess that.
　このような推察に至ったのは、上記実施例１および２で述べた成形体（圧粉磁心）の成形後の端面を肉眼および顕微鏡で観察した結果、並びに、前記端面に炭素（Ｃ）蒸着を施した後、指定元素（Ｆｅ、Ｐ）に対するＥＰＭＡ（Ｘ線マイクロアナリシス）マッピングを行った結果に基づく。なお、ＥＰＭＡの装置、分析条件およびマッピング条件を下記表３にまとめて記載する。 The reason for this inference is that the end face after molding of the molded body (powder magnetic core) described in Examples 1 and 2 was observed with the naked eye and a microscope, and carbon (C) deposition was performed on the end face. Based on the result of EPMA (X-ray microanalysis) mapping to the specified elements (Fe, P). The EPMA apparatus, analysis conditions, and mapping conditions are summarized in Table 3 below.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
（実施形態２）
　以下、本発明の実施形態２に係る圧粉磁心用混合粉末およびこの混合粉末を用いた圧粉磁心の構成について、実施形態を例示しつつ、詳細に説明する。 (Embodiment 2)
Hereinafter, the mixed powder for a powder magnetic core according to the second embodiment of the present invention and the structure of the powder magnetic core using the mixed powder will be described in detail while illustrating the embodiment.
　本発明の実施形態２に係る圧粉磁心用混合粉末（すなわち、第２発明に係る圧粉磁心用混合粉末）は、６００μｍ以下の粒径で、かつ、７５μｍ未満の粒径の存在比率が２質量％以下である鉄基軟磁性粉末を用い、この鉄基軟磁性粉末が絶縁被膜で被覆処理された鉄基軟磁性粉末Ｃと絶縁被膜で被覆処理されていない鉄基軟磁性粉末Ｄとを含み、
　前記鉄基軟磁性粉末Ｃと前記鉄基軟磁性粉末Ｄの混合割合が下記（２）式を満足することを特徴とする圧粉磁心用混合粉末である。
　１質量％≦［鉄基軟磁性粉末Ｄの質量／（鉄基軟磁性粉末Ｃの質量＋鉄基軟磁性粉末Ｄの質量）］×１００≦３０質量％　－－－（２） The powder mixture for powder magnetic core according to Embodiment 2 of the present invention (that is, the powder mixture for powder magnetic core according to the second invention) has a particle size of 600 μm or less and a particle size ratio of less than 75 μm is 2. Using iron-based soft magnetic powder having a mass% or less, an iron-based soft magnetic powder C coated with an insulating coating and an iron-based soft magnetic powder D not coated with an insulating coating. Including
A mixed powder for a dust core, wherein a mixing ratio of the iron-based soft magnetic powder C and the iron-based soft magnetic powder D satisfies the following formula (2).
1 mass% ≦ [mass of iron-based soft magnetic powder D / (mass of iron-based soft magnetic powder C + mass of iron-based soft magnetic powder D)] × 100 ≦ 30 mass% −−− (2)
　上記鉄基軟磁性粉末を用いた場合、実施形態１で採用した鉄基軟磁性粉末に比べて粉末がより粗粒化されているため、粉末の比表面積がより減少し、圧縮過程での粉末間の摩擦や加工硬化がより少なくなり、同一の成形圧力でも成形体密度がより向上する。したがって、実施形態１で採用した粉末を採用した場合に比して、成形体内の鉄基軟磁性粉末の量がより増加するばかりでなく、空隙もより減少するため、実施形態１の場合に比して磁束密度や透磁率がそれぞれより向上する。 When the iron-based soft magnetic powder is used, since the powder is more coarsened than the iron-based soft magnetic powder employed in Embodiment 1, the specific surface area of the powder is further reduced, and the powder in the compression process Friction and work hardening in between are reduced, and the density of the molded body is further improved even at the same molding pressure. Therefore, compared to the case of the first embodiment, not only the amount of the iron-based soft magnetic powder in the molded body is increased but also the voids are reduced as compared with the case where the powder adopted in the first embodiment is adopted. Thus, the magnetic flux density and the magnetic permeability are further improved.
　また、本実施形態のような、より粗粒化した鉄基軟磁性粉末を用いた場合は、実施形態１で採用した鉄基軟磁性粉末を用いた場合に比べて、同一重量当たりの生粉（上記鉄基軟磁性粉末Ｄ）の個数が少なくなる。そのため、本実施形態に係る圧粉磁心が呈する構造（すなわち、絶縁被膜で被覆処理された鉄基軟磁性粉末Ｃを絶縁被膜で被覆処理されていない鉄基軟磁性粉末Ｄが取り囲むような構造と推察される構造）の場合、実施形態１で採用した鉄基軟磁性粉末を用いた場合における所定の鉄損｛すなわち、生粉混合割合が０質量％の場合の鉄損に対する鉄損の増加が５％以内｝程度に抑えるためであるならば、圧粉磁心としての成形体内に上記鉄基軟磁性粉末Ｄを取り込む割合（すなわち、上記鉄基軟磁性粉末Ｄの添加割合）をより増加可能である。このことからも、本実施形態の場合は、実施形態１で採用した鉄基軟磁性粉末を用いた場合に比べて、より磁束密度の向上が期待できる。 In addition, when using a coarser iron-based soft magnetic powder as in the present embodiment, raw flour per weight is greater than when using the iron-based soft magnetic powder employed in the first embodiment. The number of (the iron-based soft magnetic powder D) is reduced. Therefore, the structure of the powder magnetic core according to the present embodiment (that is, the structure in which the iron-based soft magnetic powder D not coated with the insulating coating surrounds the iron-based soft magnetic powder C coated with the insulating coating) (Inferred structure) In the case of using the iron-based soft magnetic powder employed in Embodiment 1, the predetermined iron loss {that is, the increase in iron loss relative to the iron loss when the raw powder mixing ratio is 0% by mass is 5% or less}, it is possible to further increase the ratio of the iron-based soft magnetic powder D taken into the molded body as the dust core (that is, the ratio of the iron-based soft magnetic powder D added). is there. Also from this fact, in the case of the present embodiment, the improvement of the magnetic flux density can be expected more than in the case where the iron-based soft magnetic powder employed in the first embodiment is used.
　なお、本実施形態における鉄基軟磁性粉末の材質は、実施形態１で採用した鉄基軟磁性粉末と同様のものを用いることが可能である。また、所定の鉄損に抑えながら、同時に成形体に成形する際の圧縮性をより向上させることを意図しているため、粒度の大きな成分（例えば、１０６μｍ以上６００μｍ以下）を通常より多く含み、かつ、７５μｍ未満の粒径の存在が２％以下である鉄基軟磁性粉末がより好ましい（詳細は、下記表４参照）。
　なお、上記鉄基軟磁性粉末は、日本粉末冶金工業会で規定される「金属粉のふるい分析試験方法」（ＪＰＭＡ　　ＰＯ２－１９９２）に準拠して、まず目開き６００μｍの篩を用いて篩い分けした後、さらに下記表４に示す粒度に対応する目開き２５０μｍから１０６μｍの篩を用いて順次篩い分けした。これにより、本実施形態において定義される鉄基軟磁性粉末｛粗粒化した鉄基軟磁性粉末（すなわち、実質７５μｍ以上～６００μｍ以下の粒径であり、かつ、７５μｍ未満の粒径の存在比率が２質量％以下である鉄基軟磁性粉末）｝が得られる。なお、目開き１０６μｍの篩を用いて篩い分けしているにも拘らず、下記表４に示すように、１０６μｍ未満の粒径が含まれている。これは、篩網の上には、篩い目よりも細かい粒径の粉末が若干量だけ残るためである。 The material of the iron-based soft magnetic powder in the present embodiment can be the same as that of the iron-based soft magnetic powder employed in the first embodiment. In addition, since it is intended to further improve the compressibility at the time of forming into a molded body while suppressing to a predetermined iron loss, it contains more components with a large particle size (for example, 106 μm or more and 600 μm or less), In addition, iron-based soft magnetic powder having a particle size of less than 75 μm of 2% or less is more preferable (see Table 4 below for details).
The iron-based soft magnetic powder is first sieved using a sieve having an aperture of 600 μm in accordance with “Metal Powder Sieve Analysis Test Method” (JPMA PO2-1992) prescribed by the Japan Powder Metallurgy Industry Association. After that, sieving was sequentially performed using a sieve having an opening of 250 μm to 106 μm corresponding to the particle sizes shown in Table 4 below. As a result, the iron-based soft magnetic powder defined in the present embodiment {roughened iron-based soft magnetic powder (that is, the abundance ratio of a particle size of substantially 75 μm to 600 μm and less than 75 μm). Of iron-based soft magnetic powder) is 2 mass% or less. In addition, although it sifts using the sieve of 106 micrometers of mesh openings, as shown in following Table 4, the particle size of less than 106 micrometers is contained. This is because a small amount of powder having a particle size finer than the sieve mesh remains on the sieve mesh.
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
　また、本実施形態における鉄基軟磁性粉末Ｃとは、上記鉄基軟磁性粉末の表面を、上述した絶縁被膜（すなわち、実施形態１で採用したものと同様の絶縁被膜）で被覆処理したものを指して言う。また、本実施形態における上記絶縁被膜は、実施形態１と同様に少なくとも無機系絶縁被膜であることが好ましい。この無機系絶縁被膜としてのリン酸系化成被膜は、上記鉄基軟磁性粉末に対する濡れ性が良く、この被膜で鉄基軟磁性粉末の表面を均一に被覆することが可能である点からより好ましい。 Further, the iron-based soft magnetic powder C in this embodiment is obtained by coating the surface of the iron-based soft magnetic powder with the above-described insulating coating (that is, the same insulating coating as used in Embodiment 1). Point to and say. Moreover, it is preferable that the said insulation film in this embodiment is an inorganic insulation film at least similarly to Embodiment 1. The phosphoric acid-based chemical conversion coating as the inorganic insulating coating is more preferable because it has good wettability with respect to the iron-based soft magnetic powder and can uniformly coat the surface of the iron-based soft magnetic powder with this coating. .
　上述したリン酸系化成被膜の形成には、実施形態１と同様の処理液を用いた。また、上記鉄基軟磁性粉末１００部に対して、この処理液を５部混合し，大気中２００℃で乾燥させた。これにより、このリン酸系化成被膜の厚みは、１０～１００ｎｍとなる。 For the formation of the above-described phosphoric acid-based chemical conversion film, the same treatment liquid as in Embodiment 1 was used. Further, 5 parts of this treatment liquid was mixed with 100 parts of the iron-based soft magnetic powder and dried at 200 ° C. in the atmosphere. As a result, the thickness of the phosphoric acid-based chemical conversion film becomes 10 to 100 nm.
（本発明の実施形態２に係る鉄基軟磁性粉末Ｄ（すなわち、粗粒化した鉄基軟磁性粉末Ｄ）の成形圧と成形体密度の関係）
　図８は、本発明の実施形態２に係る鉄基軟磁性粉末Ｄの成形圧と成形体密度の関係を説明するための説明図である。 (Relationship between molding pressure and compact density of iron-based soft magnetic powder D (ie, coarse-grained iron-based soft magnetic powder D) according to Embodiment 2 of the present invention)
FIG. 8 is an explanatory diagram for explaining the relationship between the molding pressure and the compact density of the iron-based soft magnetic powder D according to the second embodiment of the present invention.
　図８において、上記鉄基軟磁性粉末Ｄに潤滑剤としてのエチレンビスラウリン酸アミドを０．３質量％添加した後、金型（外径φ３１．７５ｍｍ×内径φ１２．７ｍｍ×高さ５ｍｍ）内に入れ、室温下で成形圧を５００、６５０、８００、９００および１１００ＭＰａの範囲で変化させ、それぞれトロイダル形状にプレス成形し成形体を得た。 In FIG. 8, after adding 0.3% by mass of ethylenebislauric acid amide as a lubricant to the iron-based soft magnetic powder D, inside the mold (outer diameter φ31.75 mm × inner diameter φ12.7 mm × height 5 mm) The molding pressure was changed in the range of 500, 650, 800, 900 and 1100 MPa at room temperature, and each was press-molded into a toroidal shape to obtain a molded body.
　図８において、上記鉄基軟磁性粉末Ｄ（すなわち、粗粒化した鉄基軟磁性粉末Ｄ）を用いた場合には、図１に示す生粉のみの場合（図８内には同時に表示せず）と比べても、低い成形圧の領域（例えば、９００ＭＰａ以下）でより成形体密度が高くなっていることが分かる。これは、すでに上述したように、粉末の比表面積がより減少し、圧縮過程での粉末間の摩擦や加工硬化がより少なくなるためである。したがって、実施形態１で採用した粉末を採用した場合に比して、より低い成形圧の領域でも成形体内の鉄基軟磁性粉末の量がより増加するばかりでなく、より低い成形圧の領域でも空隙もより減少するため、実施形態１の場合に比して、より低い成形圧の領域でも磁束密度（詳細は、後記図１２参照）や透磁率（図示せず）がそれぞれより向上することを示唆している。このことは、電磁気部品の小型化が期待できるため、その技術的な意義は、非常に大きい。 In FIG. 8, when the iron-based soft magnetic powder D (that is, the coarse-grained iron-based soft magnetic powder D) is used, only the raw powder shown in FIG. 1 (shown simultaneously in FIG. 8). 3), it can be seen that the density of the molded body is higher in the low molding pressure region (for example, 900 MPa or less). This is because, as already described above, the specific surface area of the powder is further reduced, and friction between the powder and work hardening are reduced during the compression process. Therefore, as compared with the case where the powder employed in the first embodiment is employed, not only the amount of iron-based soft magnetic powder in the molded body is increased even in a lower molding pressure region, but also in a lower molding pressure region. Since the air gap is also reduced, the magnetic flux density (see FIG. 12 for details) and the magnetic permeability (not shown) are further improved in the region of lower molding pressure than in the case of the first embodiment. Suggests. Since this can be expected to reduce the size of electromagnetic components, its technical significance is very large.
　よって、成形体に成形する際の圧縮性をより向上させることが可能でありながらも（図８参照）、同時に圧粉磁心において所定の鉄損｛すなわち、生粉混合割合が０質量％の場合の鉄損に対する鉄損の増加が５％以内｝程度に抑えるためには、圧粉磁心としての成形体内に上記鉄基軟磁性粉末Ｄを取り込む割合（すなわち、上記鉄基軟磁性粉末Ｄの添加割合）を如何なる範囲まで増加させることが可能であるのか確証する必要がある。これについて、以下の実施例４で詳述する。 Therefore, while it is possible to further improve the compressibility during molding into a molded body (see FIG. 8), at the same time, a predetermined iron loss in the dust core {ie, when the raw powder mixing ratio is 0% by mass In order to suppress the increase in the iron loss with respect to the iron loss within 5%}, the ratio of incorporating the iron-based soft magnetic powder D into the compact as the dust core (that is, the addition of the iron-based soft magnetic powder D) It is necessary to confirm to what extent it is possible to increase the ratio). This will be described in detail in Example 4 below.
（生粉混合割合と鉄損の関係）
　図９～図１１は、本実施の形態に係る圧粉磁心における、生粉混合割合と鉄損の関係を示す特性図である。鉄損を測定する圧粉磁心（測定試料）に使用する鉄基軟磁性粉末は、上記表４に詳述したものを使用する。また、表４に示す鉄基軟磁性粉末（すなわち、６００μｍ以下の粒径で、かつ、７５μｍ未満の粒径の存在比率が２質量％以下である鉄基軟磁性粉末）を用いた圧粉磁心用混合粉末｛鉄基軟磁性粉末Ｃと鉄基軟磁性粉末Ｄ（生粉）の混合粉末｝に潤滑剤としてのエチレンビスラウリン酸アミドを０．３質量％添加した後、金型（外径φ４５ｍｍ×内径φ３３ｍｍ×高さ５ｍｍ）内に入れ、室温下で成形圧９００ＭＰａにてトロイダル形状にプレス成形し成形体を得た。この成形体を所定温度（例えば、３５０℃、３０分）で大気中焼鈍し、圧粉磁心とする。この圧粉磁心用混合粉末の生粉混合割合は、図９～図１１に示す通り、いずれも０質量％｛すなわち、鉄基軟磁性粉末Ｃ（リン酸系化成被膜で被覆処理した純鉄粉）のみ｝、５質量％、１０質量％、２０質量％、３０質量％、５０質量％、７５質量％および１００質量％（すなわち、鉄基軟磁性粉末Ｄのみ）である。なお、ここで生粉混合割合とは、［鉄基軟磁性粉末Ｄの質量／（鉄基軟磁性粉末Ｃの質量＋鉄基軟磁性粉末Ｄの質量）］×１００と定義される。また、鉄損の測定には、交流Ｂ－Ｈアナライザーを用いた。また、測定条件および圧粉磁心を形成した際の成形圧力（成形圧）の各諸元を下記表５にまとめて示す。 (Relationship between raw powder mixing ratio and iron loss)
9 to 11 are characteristic diagrams showing the relationship between the raw powder mixing ratio and the iron loss in the dust core according to the present embodiment. The iron-based soft magnetic powder used for the dust core (measurement sample) for measuring the iron loss is the one detailed in Table 4 above. Further, a dust core using the iron-based soft magnetic powder shown in Table 4 (that is, an iron-based soft magnetic powder having a particle size of 600 μm or less and a particle size of less than 75 μm is 2% by mass or less). After adding 0.3% by mass of ethylenebislauric acid amide as a lubricant to the mixed powder {mixed powder of iron-based soft magnetic powder C and iron-based soft magnetic powder D (raw powder)}, the mold (outer diameter (φ45 mm × inner diameter φ33 mm × height 5 mm) and press molded into a toroidal shape at a molding pressure of 900 MPa at room temperature to obtain a molded body. This molded body is annealed in the atmosphere at a predetermined temperature (for example, 350 ° C., 30 minutes) to obtain a dust core. As shown in FIG. 9 to FIG. 11, the raw powder mixing ratio of this powder mixture for powder magnetic cores is 0% by mass {that is, iron-based soft magnetic powder C (pure iron powder coated with a phosphate chemical conversion coating). ) Only}, 5% by mass, 10% by mass, 20% by mass, 30% by mass, 50% by mass, 75% by mass and 100% by mass (that is, iron-based soft magnetic powder D only). Here, the raw powder mixing ratio is defined as [mass of iron-based soft magnetic powder D / (mass of iron-based soft magnetic powder C + mass of iron-based soft magnetic powder D)] × 100. An AC BH analyzer was used to measure the iron loss. In addition, Table 5 below shows the measurement conditions and various specifications of the molding pressure (molding pressure) when the dust core was formed.
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
　図９～図１１のいずれの場合も、生粉混合割合が０質量％～３０質量％の範囲（よって、後記詳述する、圧縮性の向上による成形体密度のより一層の向上を考慮に入れると、少なくとも１質量％～３０質量％の範囲）において、実施形態１で採用した鉄基軟磁性粉末を用いた場合における所定の鉄損｛すなわち、生粉混合割合が０質量％の場合の鉄損に対する鉄損の増加が５％以内｝程度に十分抑えられていることが判明した。 In any of the cases shown in FIGS. 9 to 11, the raw powder mixing ratio is in the range of 0% by mass to 30% by mass. And a predetermined iron loss when using the iron-based soft magnetic powder employed in Embodiment 1 (that is, iron when the raw powder mixing ratio is 0% by mass) It was found that the increase in iron loss relative to loss was sufficiently suppressed to within 5%}.
（生粉混合割合と成形体密度および磁束密度の関係）
　図１２において、上記圧粉磁心用混合粉末に潤滑剤としてのエチレンビスラウリン酸アミドを０．３質量％添加した後、金型（外径φ３１．７５ｍｍ×内径φ１２．７ｍｍ×高さ５ｍｍ）内に入れ、室温下で成形圧１１００ＭＰａにて、トロイダル形状にプレス成形し成形体を得た。なお、磁束密度の測定には、直流Ｂ－Ｈトレーサーを用いた。 (Relationship between raw powder mixing ratio, compact density and magnetic flux density)
In FIG. 12, after adding 0.3% by mass of ethylenebislauric acid amide as a lubricant to the powder mixture for powder magnetic core, inside the mold (outer diameter φ31.75 mm × inner diameter φ12.7 mm × height 5 mm) And pressed into a toroidal shape at a molding pressure of 1100 MPa at room temperature to obtain a molded body. A DC BH tracer was used for measuring the magnetic flux density.
　その結果、図１２に示すように生粉混合割合が０質量％を除き、すなわち少なくとも１質量％以上になると、本願発明の作用効果が発揮され、圧縮性の向上による成形体密度のより一層の向上が認められる。また、生粉混合割合が、少なくとも１質量％以上になると、磁束密度も生粉混合割合が０質量％の時のレベルに比して同等以上が得られる。 As a result, as shown in FIG. 12, when the raw powder mixing ratio excludes 0% by mass, that is, at least 1% by mass or more, the effect of the present invention is exhibited, and the compact density due to the improvement in compressibility is further improved. An improvement is observed. When the raw powder mixing ratio is at least 1% by mass or more, the magnetic flux density is equal to or higher than the level when the raw powder mixing ratio is 0% by mass.
（実施形態３）
　以下、本発明の実施形態３に係る圧粉磁心用混合粉末およびこの混合粉末を用いた圧粉磁心の構成について、実施形態を例示しつつ、詳細に説明する。 (Embodiment 3)
Hereinafter, the mixed powder for a powder magnetic core according to the third embodiment of the present invention and the structure of the powder magnetic core using the mixed powder will be described in detail while illustrating the embodiment.
　本発明の実施形態３に係る圧粉磁心用混合粉末（すなわち、第５発明に係る圧粉磁心用混合粉末）は、６００μｍ以下の粒径の鉄基軟磁性粉末を用い、この鉄基軟磁性粉末の表面に無機系絶縁被膜と耐熱性樹脂被膜がこの順で被覆処理された鉄基軟磁性粉末Ｅと無機系絶縁被膜と耐熱性樹脂被膜で被覆処理されていない鉄基軟磁性粉末Ｆとを含み、
　前記鉄基軟磁性粉末Ｅと前記鉄基軟磁性粉末Ｆの混合割合が下記（３）式を満足することを特徴とする圧粉磁心用混合粉末である。
　３質量％≦［鉄基軟磁性粉末Ｆの質量／（鉄基軟磁性粉末Ｅの質量＋鉄基軟磁性粉末Ｆの質量）］×１００≦１０質量％　－－－（３） The mixed powder for a dust core according to Embodiment 3 of the present invention (that is, the mixed powder for a dust core according to the fifth invention) uses an iron-based soft magnetic powder having a particle diameter of 600 μm or less. An iron-based soft magnetic powder E in which an inorganic insulating coating and a heat-resistant resin coating are coated in this order on the surface of the powder; an iron-based soft magnetic powder F that is not coated with an inorganic insulating coating and a heat-resistant resin coating; Including
A mixed powder for a dust core, wherein a mixing ratio of the iron-based soft magnetic powder E and the iron-based soft magnetic powder F satisfies the following expression (3).
3% by mass ≦ [mass of iron-based soft magnetic powder F / (mass of iron-based soft magnetic powder E + mass of iron-based soft magnetic powder F)] × 100 ≦ 10% by mass --- (3)
　上記二重被膜された鉄基軟磁性粉末Ｅと上記二重被膜されていない鉄基軟磁性粉末Ｆの混合割合が上記（３）式を満足する混合粉末を採用しているため、二重被膜を構成する特に耐熱性樹脂被膜の働きと相俟って、実施形態２で採用した混合粉末に対しても、圧縮過程での粉末間の摩擦や加工硬化が同等以下に少なくなり、成形体密度も同等以上に向上する。すなわち、実施形態１で採用した混合粉末に比して、成形体内の鉄基軟磁性粉末の量がより増加するばかりでなく、空隙もより減少するため、実施形態１の場合に比して磁束密度がさらに向上する。 Since the mixed ratio of the double-coated iron-based soft magnetic powder E and the non-double-coated iron-based soft magnetic powder F satisfies the above formula (3), a double-coated film is used. In combination with the action of the heat-resistant resin film that constitutes the composition, the friction and work-hardening between the powders during the compression process are less than or equal to those of the mixed powder adopted in Embodiment 2, and the compact density Will improve to the same or better level. That is, not only the amount of the iron-based soft magnetic powder in the molded body is increased more than the mixed powder employed in the first embodiment, but also the gap is reduced, so that the magnetic flux is smaller than that in the first embodiment. The density is further improved.
　また、本実施形態のような混合粉末を採用し、圧縮成形により作成した圧粉磁心が呈する構造｛すなわち、二重被膜された鉄基軟磁性粉末Ｅを被覆処理されていない鉄基軟磁性粉末Ｆ（生粉Ｆ）が取り囲むような構造と推察される構造｝の場合、実施形態１で採用した鉄基軟磁性粉末を用いた場合における所定の鉄損｛すなわち、生粉混合割合が０質量％の場合の鉄損に対する鉄損の増加が５％以内｝程度に抑えるためであるならば、圧粉磁心としての成形体内に上記鉄基軟磁性粉末Ｆを取り込む割合（すなわち、上記鉄基軟磁性粉末Ｆの添加割合）をより増加可能である。このことからも、本実施形態の場合は、実施形態１で採用した鉄基軟磁性粉末を用いた場合に比べて、より磁束密度の向上が期待できる。また、この作用効果は、後記詳述するように、生粉Ｆの粒度依存性も比較的少ない。 Further, a structure exhibited by a powder magnetic core prepared by compression molding using a mixed powder as in the present embodiment {that is, an iron-based soft magnetic powder not coated with a double-coated iron-based soft magnetic powder E F (structure presumed to be surrounded by raw powder F)}, the predetermined iron loss when the iron-based soft magnetic powder employed in Embodiment 1 is used {ie, the raw powder mixing ratio is 0 mass %, The iron-based soft magnetic powder F is incorporated into the compact as a dust core (ie, the iron-based soft magnetic powder F). The addition ratio of the magnetic powder F) can be further increased. Also from this fact, in the case of the present embodiment, the improvement of the magnetic flux density can be expected more than in the case where the iron-based soft magnetic powder employed in the first embodiment is used. In addition, as described in detail later, this effect is relatively small in the particle size dependence of the raw powder F.
　なお、本実施形態における鉄基軟磁性粉末の材質は、実施形態１で採用した鉄基軟磁性粉末と同様のものを用いることが可能である。また、混合粉末の中に二重被膜された鉄基軟磁性粉末Ｅを含むため、所定の鉄損に抑えながら、同時に成形体に成形する際の圧縮性をより向上させることを目指しながらも、鉄基軟磁性粉末の粒度分布は実施形態１や２の場合に比べると、６００μｍ以下の粒径の広い範囲に分布している（詳細は、下記表６参照）。なお、上記鉄基軟磁性粉末は、日本粉末冶金工業会で規定される「金属粉のふるい分析試験方法」（ＪＰＭＡ　　ＰＯ２－１９９２）に準拠して、まず目開き６００μｍの篩を用いて篩い分けした後、さらに目開き１５０μｍの篩を用いて、この篩の網上に残った粗い粉粒の生粉Ｆ１｛以下、Ｆ１（生粉粗粉）と称す｝と網を通過した微粒の生粉Ｆ２｛以下、Ｆ２（生粉微粉）と称す｝に篩い分けした。また、このＦ１（生粉粗粉）とＦ２（生粉微粉）をすべて含むものをＦ３（生粉全粒度）と称す。これにより、本実施形態において定義される鉄基軟磁性粉末が得られる。なお、上記被覆処理されていない鉄基軟磁性粉末Ｆ（生粉Ｆ）とは、このＦ１（生粉粗粉）、Ｆ２（生粉微粉）とＦ３（生粉全粒度）のいずれかを指す。この中でも、Ｆ１（生粉粗粉）とＦ３（生粉全粒度）を用いた場合が、より好ましい作用効果を発揮する。 It should be noted that the material of the iron-based soft magnetic powder in this embodiment can be the same as the iron-based soft magnetic powder employed in the first embodiment. In addition, because the mixed powder contains the double-coated iron-based soft magnetic powder E, while suppressing the predetermined iron loss, while aiming to further improve the compressibility when molding into a molded body, Compared with Embodiments 1 and 2, the particle size distribution of the iron-based soft magnetic powder is distributed over a wide range of particle sizes of 600 μm or less (see Table 6 below for details). The iron-based soft magnetic powder is first sieved using a sieve having an aperture of 600 μm in accordance with “Metal Powder Sieve Analysis Test Method” (JPMA PO2-1992) prescribed by the Japan Powder Metallurgy Industry Association. After that, using a sieve having an opening of 150 μm, coarse powder F1 {hereinafter referred to as F1 (raw powder coarse powder)} remaining on the screen and fine raw powder passed through the mesh Sieve into F2 {hereinafter referred to as F2 (raw flour fines)}. Moreover, what contains all this F1 (raw powder coarse powder) and F2 (raw powder fine powder) is called F3 (raw powder full particle size). Thereby, the iron-based soft magnetic powder defined in this embodiment is obtained. The iron-based soft magnetic powder F (raw powder F) that has not been coated is any one of F1 (raw powder coarse powder), F2 (raw powder fine powder), and F3 (raw powder full particle size). . Among these, the case where F1 (raw powder coarse powder) and F3 (raw powder whole particle size) are used exhibits a more preferable effect.
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000006
　また、本実施形態における鉄基軟磁性粉末Ｅとは、上記鉄基軟磁性粉末の表面を、上述した無機系絶縁被膜（すなわち、実施形態１で採用したものと同様の絶縁被膜）と耐熱性樹脂被膜（後記詳述する）でこの順に被覆処理したものを指して言う。また、本実施形態における上記無機系絶縁被膜としてのリン酸系化成被膜（下層）は、上記鉄基軟磁性粉末に対する濡れ性が良く、この被膜で鉄基軟磁性粉末の表面を均一に被覆することが可能である点からより好ましい。 Further, the iron-based soft magnetic powder E in the present embodiment refers to the surface of the iron-based soft magnetic powder and the above-described inorganic insulating coating (that is, the same insulating coating as that employed in Embodiment 1) and heat resistance. A resin film (described in detail later) refers to what is coated in this order. Further, the phosphoric acid-based chemical conversion coating (lower layer) as the inorganic insulating coating in this embodiment has good wettability to the iron-based soft magnetic powder, and the surface of the iron-based soft magnetic powder is uniformly coated with this coating. It is more preferable because it is possible.
　上述したリン酸系化成被膜（下層）の形成には、実施形態１と同様の処理液を用いた。また、上記鉄基軟磁性粉末１００部に対して、この処理液を５部混合し，大気中２００℃で乾燥させた。これにより、このリン酸系化成被膜（下層）の厚みは、１０～１００ｎｍとなる。 For the formation of the phosphoric acid-based chemical conversion film (lower layer) described above, the same treatment liquid as that in Embodiment 1 was used. Further, 5 parts of this treatment liquid was mixed with 100 parts of the iron-based soft magnetic powder and dried at 200 ° C. in the atmosphere. Thereby, the thickness of the phosphoric acid-based chemical conversion film (lower layer) becomes 10 to 100 nm.
　上記鉄基軟磁性粉末の表面に無機系絶縁被膜としてのリン酸系化成被膜（下層）を形成した後、さらにその表面に、下記のような耐熱性樹脂被膜としてのシリコーン樹脂被膜（上層）を形成した。以下に、このシリコーン樹脂被膜（上層）について、詳述する。 After forming a phosphoric acid-based chemical conversion coating (lower layer) as an inorganic insulating coating on the surface of the iron-based soft magnetic powder, a silicone resin coating (upper layer) as the following heat-resistant resin coating is further formed on the surface. Formed. Below, this silicone resin film (upper layer) is explained in full detail.
　シリコーン樹脂被膜（上層）の形成は、シリコーン樹脂をアルコール類やトルエン、キシレン等の石油系有機溶剤等に溶解させたシリコーン樹脂溶液と、上述したリン酸系化成被膜（下層）を表面に形成した鉄基軟磁性粉末とを混合し、次いで必要に応じて前記有機溶剤等を蒸発させることによって行った。これにより、所定のシリコーン樹脂被膜（上層）の厚みが得られる。このシリコーン樹脂被膜（上層）の厚みは、１～２００ｎｍが好ましく、より好ましくは２０～１５０ｎｍである。 The silicone resin coating (upper layer) was formed by forming a silicone resin solution in which a silicone resin was dissolved in a petroleum-based organic solvent such as alcohols, toluene, and xylene, and the above-described phosphoric acid-based chemical conversion coating (lower layer) on the surface. This was performed by mixing with iron-based soft magnetic powder and then evaporating the organic solvent or the like as necessary. Thereby, the thickness of a predetermined silicone resin film (upper layer) is obtained. The thickness of the silicone resin coating (upper layer) is preferably 1 to 200 nm, more preferably 20 to 150 nm.
　本発明で用いられる上記シリコーン樹脂は、従来から公知のシリコーン樹脂を用いることができ、例えば市販品として、信越化学工業社製のＫＲ２６１、ＫＲ２７１、ＫＲ２７２、ＫＲ２７５、ＫＲ２８０、ＫＲ２８２、ＫＲ２８５、ＫＲ２５１、ＫＲ１５５、ＫＲ２２０、ＫＲ２０１、ＫＲ２０４、ＫＲ２０５、ＫＲ２０６、ＫＲ２２５、ＫＲ３１１、ＫＲ７００、ＳＡ－４、ＥＳ－１００１、ＥＳＩ ＯＯＩ Ｎ、ＥＳＩＯＯ２Ｔ、ＫＲ３０９３や東レ・ダウコーニング社製のＳＲ２１００、ＳＲ２１０１、ＳＲ２１０７、ＳＲ２１１０、ＳＲ２１０８、ＳＲ２１０９、ＳＲ２１１５、ＳＲ２４００、ＳＲ２４１０、ＳＲ２４１１、ＳＨ８０５、ＳＨ８０６Ａ、ＳＨ８４０などが挙げられる。また、熱的安定性の観点から、メチル基が５０モル％以上のメチルフェニルシリコーン樹脂（例えば、信越化学工業社製のＫＲ２２５、ＫＲ３１１等）を用いることが好ましく、メチル基が７０モル％以上のメチルフェニルシリコーン樹脂（例えば、信越化学工業社製のＫＲ３００等）がより好ましく、フェニル基を全く持たないメチルシリコーン樹脂（例えば、東レ・ダウコーニング社製のＳＲ２４００、信越化学工業社製のＫＲ２５１、ＫＲ４００、ＫＲ２２０Ｌ、ＫＲ２４２Ａ、ＫＲ２４０、ＫＲ５００、ＫＣ８９等）がさらに好ましい。中でもＫＲ２２０Ｌ、ＳＲ２４００が特に好ましい。 As the silicone resin used in the present invention, a conventionally known silicone resin can be used. For example, as commercially available products, KR261, KR271, KR272, KR275, KR280, KR282, KR285, KR251, KR155 manufactured by Shin-Etsu Chemical Co., Ltd. , KR220, KR201, KR204, KR205, KR206, KR225, KR311, KR700, SA-4, ES-1001, ESI OOI N, ESIOO2T, KR3093 and SR2100, SR2101, SR2107, SR2110, SR2108, manufactured by Toray Dow Corning SR2109, SR2115, SR2400, SR2410, SR2411, SH805, SH806A, SH840 and the like. From the viewpoint of thermal stability, it is preferable to use a methylphenyl silicone resin having a methyl group of 50 mol% or more (for example, KR225, KR311, etc. manufactured by Shin-Etsu Chemical Co., Ltd.), and the methyl group is 70 mol% or more. Methyl phenyl silicone resin (for example, KR300 manufactured by Shin-Etsu Chemical Co., Ltd.) is more preferable, and methyl silicone resin having no phenyl group (for example, SR2400 manufactured by Toray Dow Corning Co., Ltd., KR251, KR400 manufactured by Shin-Etsu Chemical Co., Ltd.) KR220L, KR242A, KR240, KR500, KC89, etc.) are more preferable. Of these, KR220L and SR2400 are particularly preferable.
（本発明の実施の形態３に係る圧粉磁心用混合粉末の生粉混合割合と成形体密度の関係）
　図１３は、本発明の実施の形態３に係る圧粉磁心用混合粉末の含有される生粉Ｆの粒度を変化させた場合における、生粉混合割合と成形体密度の関係を説明するための説明図であって、（ａ）は成形圧８００ＭＰａ、（ｂ）は成形圧１０００ＭＰａ、（ｃ）は成形圧１２００ＭＰａである。 (Relationship between raw powder mixing ratio and compact density of powder mixture for powder magnetic core according to Embodiment 3 of the present invention)
FIG. 13 is a view for explaining the relationship between the raw powder mixing ratio and the compact density when the particle size of raw powder F contained in the powder mixture for powder magnetic core according to Embodiment 3 of the present invention is changed. It is explanatory drawing, Comprising: (a) is a forming pressure of 800 MPa, (b) is a forming pressure of 1000 MPa, and (c) is a forming pressure of 1200 MPa.
　図１３においては、圧縮成形を行う成形型（外径φ３１．７５ｍｍ×内径φ１２．７ｍｍ×高さ５ｍｍ）の内壁面に潤滑剤（例えば、エチレンビスアミドをアルコールに懸濁させた物）を予め刷毛で塗布し、この成形型に上記鉄基軟磁性粉末の表面にリン酸系化成被膜（下層）とシリコーン樹脂被膜（上層）がこの順で被覆処理された鉄基軟磁性粉末Ｅと被覆処理されていない鉄基軟磁性粉末Ｆとからなる混合粉末を入れ、室温下で成形圧を８００、１０００および１２００ＭＰａの範囲で変化させ、それぞれトロイダル形状にプレス成形し成形体を得た。なお、前記混合粉末中には潤滑剤を添加しない。 In FIG. 13, a lubricant (for example, a material in which ethylenebisamide is suspended in alcohol) is brushed in advance on the inner wall surface of a mold for compression molding (outer diameter φ31.75 mm × inner diameter φ12.7 mm × height 5 mm). The surface of the iron-based soft magnetic powder is coated with the iron-based soft magnetic powder E in which the phosphoric acid-based chemical conversion coating (lower layer) and the silicone resin coating (upper layer) are coated in this order on the mold. A mixed powder composed of non-iron-based soft magnetic powder F was added, and the molding pressure was changed in the range of 800, 1000 and 1200 MPa at room temperature, and each was press-molded into a toroidal shape to obtain a molded body. Note that no lubricant is added to the mixed powder.
　また、上記３種類の成形圧において、いずれの場合も生粉Ｆとして、Ｆ１（生粉粗粉）、Ｆ２（生粉微粉）、Ｆ３（生粉全粒度）の３種類について、それぞれ検討した。 Moreover, in each of the three types of molding pressures, three types of F1 (raw powder coarse powder), F2 (raw powder fine powder), and F3 (raw powder total particle size) were examined as raw powder F in each case.
　また、上記３種類の成形圧において、いずれの場合も生粉混合割合は、０質量％（すなわち、二重被膜された鉄基軟磁性粉末Ｅのみ）、３質量％、５質量％、１０質量％、２０質量％、３０質量％、５０質量％と変化させて検討した。 In each of the three types of molding pressures, the raw powder mixing ratio is 0% by mass (that is, only the double-coated iron-based soft magnetic powder E), 3% by mass, 5% by mass, and 10% by mass. %, 20% by mass, 30% by mass, and 50% by mass.
　図１３（ａ）～（ｃ）より、混合粉末中に含まれる生粉ＦがＦ１（生粉粗粉）、Ｆ２（生粉微粉）、Ｆ３（生粉全粒度）のいずれの場合も、成形圧が増加するに従って、成形体密度が高くなっていることが分かる。したがって、実施形態２の場合と同様に、成形圧の増加とともに、磁束密度がさらに向上し、それは生粉Ｆの粒度の依存性も比較的少ないことを示唆している（詳細は、後記図１４および図１５参照）。 From FIGS. 13 (a) to 13 (c), the raw powder F contained in the mixed powder is molded in any case of F1 (raw powder coarse powder), F2 (raw powder fine powder), and F3 (raw powder total particle size). It can be seen that the density of the compact increases as the pressure increases. Therefore, as in the case of the second embodiment, the magnetic flux density is further improved as the molding pressure is increased, which suggests that the particle size dependency of the raw powder F is relatively small (details are shown in FIG. 14 described later). And FIG. 15).
（生粉混合割合と磁束密度の関係）
　図１４は、同実施の形態に係る圧粉磁心（生粉Ｆの粒度を変化させた場合）における、生粉混合割合と磁束密度の関係を示す特性図（成形圧力１２００ＭＰａ）である。 (Relationship between raw powder mixing ratio and magnetic flux density)
FIG. 14 is a characteristic diagram (molding pressure 1200 MPa) showing the relationship between the raw powder mixing ratio and the magnetic flux density in the powder magnetic core (when the particle size of the raw powder F is changed) according to the embodiment.
　なお、磁束密度測定用の圧粉磁心は、図１３（ｃ）に示した成形体密度測定用の成形体（成形圧：１２００ＭＰａ）を所定温度（例えば、５００℃、３０分）で窒素中焼鈍した物を使用した。なお、磁束密度の測定には、実施形態２の場合と同様に、直流Ｂ－Ｈトレーサーを用いた。 The powder magnetic core for measuring the magnetic flux density was obtained by annealing the compact for compact density measurement (molding pressure: 1200 MPa) shown in FIG. 13C in nitrogen at a predetermined temperature (for example, 500 ° C., 30 minutes). We used what we did. For measurement of the magnetic flux density, a DC BH tracer was used as in the case of the second embodiment.
　その結果、上述した成形体密度の項でも示唆されたように、実施形態２の場合と同様に、磁束密度がさらに向上し、それは生粉Ｆの粒度の依存性も比較的少ないことを示した（図１４参照）。また、図１４に示すように、生粉混合割合が少なくとも３質量％以上になると、特にＦ１（生粉粗粉）とＦ３（生粉全粒度）の場合に、本願発明の作用効果がより発揮され、磁束密度も生粉混合割合が０質量％の時のレベルに比して向上しているのが分かる。 As a result, as suggested in the above-mentioned compact density, the magnetic flux density was further improved as in the case of the second embodiment, which showed that the particle size dependence of the raw powder F was relatively small. (See FIG. 14). Moreover, as shown in FIG. 14, when the raw powder mixing ratio is at least 3% by mass or more, the effect of the present invention is more exhibited particularly in the case of F1 (raw coarse powder) and F3 (raw powder total particle size). It can be seen that the magnetic flux density is also improved compared to the level when the raw powder mixing ratio is 0 mass%.
　図１５は、上述した成形圧力１２００ＭＰａにおける成形体密度と磁束密度の関係を一つの図にまとめて説明するための説明図である。成形体密度と磁束密度の間には、略線形な関係があり、かつ、生粉Ｆの粒度の依存性が少ないことが、この図１５からも良く分かる。 FIG. 15 is an explanatory diagram for collectively explaining the relationship between the compact density and the magnetic flux density at the compacting pressure of 1200 MPa as described above. It can be seen from FIG. 15 that there is a substantially linear relationship between the compact density and the magnetic flux density, and the particle size dependence of the raw powder F is small.
（生粉混合割合と鉄損の関係）
　図１６～図１８は、本実施の形態に係る圧粉磁心における、生粉混合割合と鉄損の関係を示す特性図である。ここで、図１６は、同実施の形態に係る圧粉磁心（生粉Ｆの粒度を変化させた場合）における、生粉混合割合と鉄損の関係を示す特性図（成形圧力１２００ＭＰａ、励磁磁界０．１Ｔ、励磁周波数１０ｋＨｚ）であって、（ａ）は生粉Ｆ１、（ｂ）は生粉Ｆ２、（ｃ）は生粉Ｆ３であり、図１７は、同実施の形態に係る圧粉磁心（生粉Ｆの粒度を変化させた場合）における、生粉混合割合と鉄損の関係を示す特性図（成形圧力１２００ＭＰａ、励磁磁界０．２Ｔ、励磁周波数１ｋＨｚ）であって、（ａ）は生粉Ｆ１、（ｂ）は生粉Ｆ２、（ｃ）は生粉Ｆ３であり、図１８は、同実施の形態に係る圧粉磁心（生粉Ｆの粒度を変化させた場合）における、生粉混合割合と鉄損の関係を示す特性図（成形圧力１２００ＭＰａ、励磁磁界０．２Ｔ、励磁周波数５ｋＨｚ）であって、（ａ）は生粉Ｆ１、（ｂ）は生粉Ｆ２、（ｃ）は生粉Ｆ３である。 (Relationship between raw powder mixing ratio and iron loss)
16 to 18 are characteristic diagrams showing the relationship between the raw powder mixing ratio and the iron loss in the dust core according to the present embodiment. Here, FIG. 16 is a characteristic diagram (forming pressure 1200 MPa, excitation magnetic field) showing the relationship between the raw powder mixing ratio and the iron loss in the powder magnetic core (when the particle size of the raw powder F is changed) according to the embodiment. 0.1T, excitation frequency 10 kHz), (a) is raw powder F1, (b) is raw powder F2, (c) is raw powder F3, and FIG. 17 shows the green compact according to the embodiment. FIG. 6 is a characteristic diagram (molding pressure 1200 MPa, excitation magnetic field 0.2 T, excitation frequency 1 kHz) showing the relationship between the raw powder mixing ratio and iron loss in a magnetic core (when the particle size of raw powder F is changed), and (a) Is the raw powder F1, (b) is the raw powder F2, (c) is the raw powder F3, and FIG. 18 is the powder magnetic core according to the embodiment (when the particle size of the raw powder F is changed). Characteristic diagram showing the relationship between raw powder mixing ratio and iron loss (molding pressure 1200 MPa, excitation magnetic field 0.2 T, excitation A frequency 5kHz), (a) is Namakona F1, (b) is Namakona F2, (c) is Namakona F3.
　また、鉄損を測定する圧粉磁心（測定試料）に使用する鉄基軟磁性粉末は、実施例６および７と同様に、上記表６に詳述したものを使用する。また、その混合粉末も、実施例６および７と同様である。また、図１６～図１８における生粉混合割合も、実施例６および７と同様に、いずれの場合も０質量％（すなわち、二重被膜された鉄基軟磁性粉末Ｅのみ）、３質量％、５質量％、１０質量％、２０質量％、３０質量％、５０質量％と変化させて検討した。 Further, the iron-based soft magnetic powder used for the dust core (measurement sample) for measuring the iron loss is the same as in Examples 6 and 7, as detailed in Table 6 above. The mixed powder is also the same as in Examples 6 and 7. In addition, the raw powder mixing ratio in FIGS. 16 to 18 was also 0% by mass (that is, only the iron-based soft magnetic powder E double-coated), 3% by mass, as in Examples 6 and 7. The change was made to 5% by mass, 10% by mass, 20% by mass, 30% by mass, and 50% by mass.
　また、鉄損測定用の圧粉磁心は、上述した磁束密度測定用の圧粉磁心と圧縮成形を行う成形型の寸法が異なる以外、すべて同じである。すなわち、鉄損測定用の圧粉磁心の成形型は、実施形態２の場合と同様に、外径φ４５ｍｍ×内径φ３３ｍｍ×高さ５ｍｍである。また、鉄損の測定には、実施形態２の場合と同様に、交流Ｂ－Ｈアナライザーを用いた。また、測定条件および圧粉磁心を形成した際の成形圧力（成形圧）の各諸元を下記表７にまとめて示す。 Further, the dust cores for measuring iron loss are all the same except that the above-described dust core for measuring magnetic flux density is different from the molding die for compression molding. That is, the mold of the powder magnetic core for measuring iron loss has an outer diameter of 45 mm, an inner diameter of 33 mm, and a height of 5 mm, as in the second embodiment. Further, in the measurement of iron loss, an AC BH analyzer was used as in the case of the second embodiment. Table 7 below collectively shows the measurement conditions and the specifications of the molding pressure (molding pressure) when the dust core was formed.
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000007
　図１６～図１８のいずれの場合も、生粉混合割合が３質量％～１０質量％の範囲（３質量％は上述した磁束密度を考慮に入れている）において、実施形態２の場合と同様に、実施形態１で採用した鉄基軟磁性粉末を用いた場合における所定の鉄損｛すなわち、生粉混合割合が０質量％の場合の鉄損に対する鉄損の増加が５％以内｝程度に十分抑えられていることが判明した。また、鉄損に関しては、生粉Ｆの粒度の依存性が少ないことが、図１６～図１８からも良く分かる。 16 to 18, in the case where the raw powder mixing ratio is in the range of 3% by mass to 10% by mass (3% by mass takes the above magnetic flux density into consideration), the same as in the case of the second embodiment. In addition, when the iron-based soft magnetic powder employed in Embodiment 1 is used, the predetermined iron loss {that is, the increase in iron loss with respect to the iron loss when the raw powder mixing ratio is 0% by mass is within about 5%} It turned out that it was suppressed enough. It can also be seen from FIGS. 16 to 18 that the iron loss is less dependent on the particle size of the raw powder F.
　以上の結果より、本実施形態のように、混合粉末中には潤滑剤を添加せず、成形型の内壁面に潤滑剤を塗布する型潤滑成形でも、本願発明の作用効果を奏することが証明された。 From the above results, it is proved that the effect of the present invention can be obtained even in the mold lubrication molding in which the lubricant is not added to the mixed powder and the lubricant is applied to the inner wall surface of the mold as in this embodiment. It was done.
　なお、絶縁被膜としては、リン酸系化成被膜以外にも、ホウ酸、ケイ酸ナトリウム等の無機系絶縁被膜や、ＳｉＯ２やＭｇＯ等の酸化物系絶縁被膜等を適宜選択して用いることもできる。また、耐熱性樹脂被膜としては、シリコーン樹脂被膜以外にも、イミド樹脂やエンジニアリングプラスチック樹脂等の耐熱性を有する樹脂からなる被膜等を適宜選択して用いることもできる。また、潤滑剤としては、エチレンビスラウリン酸アミド等のエチレンビスアミド以外にも、金属石鹸や直鎖脂肪酸アミド等、圧粉磁心の圧縮成形時に従来用いられる潤滑剤を適宜選択して用いることもできる。 In addition to phosphoric acid-based chemical conversion films, inorganic insulating films such as boric acid and sodium silicate, oxide-based insulating films such as SiO 2 and MgO, and the like can be appropriately selected and used as the insulating film. it can. Moreover, as a heat resistant resin film, besides a silicone resin film, a film made of a heat-resistant resin such as an imide resin or an engineering plastic resin can be appropriately selected and used. Further, as the lubricant, in addition to ethylene bisamide such as ethylene bislauric acid amide, it is possible to appropriately select and use a conventionally used lubricant during compression molding of a dust core such as a metal soap or a linear fatty acid amide. .
　本発明を特定の態様を参照して詳細に説明したが、本発明の精神と範囲を離れることなく様々な変更および修正が可能であることは、当業者にとって明らかである。
　なお、本出願は、２０１３年１１月２９日付けで出願された日本特許出願（特願２０１３－２４７６４７）及び２０１４年４月１８日付けで出願された日本特許出願（特願２０１４－０８６７４８）に基づいており、その全体が引用により援用される。 Although the invention has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
Note that this application is based on a Japanese patent application filed on November 29, 2013 (Japanese Patent Application No. 2013-247647) and a Japanese patent application filed on April 18, 2014 (Japanese Patent Application No. 2014-086748). Which is incorporated by reference in its entirety.

Claims (9)

  1. 　絶縁被膜で被覆処理された鉄基軟磁性粉末Ａと絶縁被膜で被覆処理されていない鉄基軟磁性粉末Ｂとを含み、
    　前記鉄基軟磁性粉末Ａと前記鉄基軟磁性粉末Ｂの混合割合が下記（１）式を満足することを特徴とする圧粉磁心用混合粉末。
    　１質量％≦［鉄基軟磁性粉末Ｂの質量／（鉄基軟磁性粉末Ａの質量＋鉄基軟磁性粉末Ｂの質量）］×１００≦５質量％　－－－（１）     Including iron-based soft magnetic powder A coated with an insulating coating and iron-based soft magnetic powder B not coated with an insulating coating,
    A mixed powder for a dust core, wherein a mixing ratio of the iron-based soft magnetic powder A and the iron-based soft magnetic powder B satisfies the following formula (1):
    1% by mass ≦ [mass of iron-based soft magnetic powder B / (mass of iron-based soft magnetic powder A + mass of iron-based soft magnetic powder B)] × 100 ≦ 5% by mass --- (1)
  2. 　６００μｍ以下の粒径で、かつ、７５μｍ未満の粒径の存在比率が２質量％以下である鉄基軟磁性粉末を用い、この鉄基軟磁性粉末が絶縁被膜で被覆処理された鉄基軟磁性粉末Ｃと絶縁被膜で被覆処理されていない鉄基軟磁性粉末Ｄとを含み、
    　前記鉄基軟磁性粉末Ｃと前記鉄基軟磁性粉末Ｄの混合割合が下記（２）式を満足することを特徴とする圧粉磁心用混合粉末。
    　１質量％≦［鉄基軟磁性粉末Ｄの質量／（鉄基軟磁性粉末Ｃの質量＋鉄基軟磁性粉末Ｄの質量）］×１００≦３０質量％　－－－（２）     An iron-based soft magnetic powder in which an iron-based soft magnetic powder having a particle size of 600 μm or less and a particle size of less than 75 μm is 2% by mass or less is coated with an insulating coating. Including powder C and iron-based soft magnetic powder D not coated with an insulating coating,
    A mixed powder for a dust core, wherein a mixing ratio of the iron-based soft magnetic powder C and the iron-based soft magnetic powder D satisfies the following formula (2):
    1 mass% ≦ [mass of iron-based soft magnetic powder D / (mass of iron-based soft magnetic powder C + mass of iron-based soft magnetic powder D)] × 100 ≦ 30 mass% −−− (2)
  3. 　前記絶縁被膜は、少なくとも無機系絶縁被膜であることを特徴とする請求項１に記載の圧粉磁心用混合粉末。 The mixed powder for a dust core according to claim 1, wherein the insulating coating is at least an inorganic insulating coating.
  4. 　前記絶縁被膜は、少なくとも無機系絶縁被膜であることを特徴とする請求項２に記載の圧粉磁心用混合粉末。 The mixed powder for a dust core according to claim 2, wherein the insulating coating is at least an inorganic insulating coating.
  5. 　前記圧粉磁心用混合粉末に潤滑剤が混合されていることを特徴とする請求項１に記載の圧粉磁心用混合粉末。 The powder mixture for dust core according to claim 1, wherein a lubricant is mixed in the powder mixture for dust core.
  6. 　前記圧粉磁心用混合粉末に潤滑剤が混合されていることを特徴とする請求項２に記載の圧粉磁心用混合粉末。 3. The powder mixture for dust core according to claim 2, wherein a lubricant is mixed in the powder mixture for dust core.
  7. 　６００μｍ以下の粒径の鉄基軟磁性粉末を用い、この鉄基軟磁性粉末の表面に無機系絶縁被膜と耐熱性樹脂被膜がこの順で被覆処理された鉄基軟磁性粉末Ｅと無機系絶縁被膜と耐熱性樹脂被膜で被覆処理されていない鉄基軟磁性粉末Ｆとを含み、
    　前記鉄基軟磁性粉末Ｅと前記鉄基軟磁性粉末Ｆの混合割合が下記（３）式を満足することを特徴とする圧粉磁心用混合粉末。
    　３質量％≦［鉄基軟磁性粉末Ｆの質量／（鉄基軟磁性粉末Ｅの質量＋鉄基軟磁性粉末Ｆの質量）］×１００≦１０質量％　－－－（３）     An iron-based soft magnetic powder having a particle diameter of 600 μm or less is used, and an iron-based soft magnetic powder E in which an inorganic insulating coating and a heat-resistant resin coating are coated in this order on the surface of the iron-based soft magnetic powder and the inorganic insulating And iron-based soft magnetic powder F not coated with a heat-resistant resin film,
    A mixed powder for a dust core, wherein a mixing ratio of the iron-based soft magnetic powder E and the iron-based soft magnetic powder F satisfies the following expression (3).
    3% by mass ≦ [mass of iron-based soft magnetic powder F / (mass of iron-based soft magnetic powder E + mass of iron-based soft magnetic powder F)] × 100 ≦ 10% by mass --- (3)
  8. 　圧縮成形を行う成形型の内壁面に潤滑剤が塗布され、前記圧粉磁心用混合粉末中には潤滑剤が添加されていないことを特徴とする請求項７に記載の圧粉磁心用混合粉末。 The mixed powder for dust core according to claim 7, wherein a lubricant is applied to an inner wall surface of a molding die for compression molding, and no lubricant is added to the mixed powder for dust core. .
  9. 　請求項１～８のいずれか１項に記載の圧粉磁心用混合粉末を圧縮成形し、この圧縮成形により得られた成形体が所定温度で焼鈍されていることを特徴とする圧粉磁心。 A powder magnetic core, wherein the powder mixture for powder magnetic core according to any one of claims 1 to 8 is compression molded, and a molded body obtained by the compression molding is annealed at a predetermined temperature.
PCT/JP2014/080548 2013-11-29 2014-11-18 Powder mixture for powder magnetic core and powder magnetic core WO2015079981A1 (en)

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