WO2024143050A1 - Soft magnetic metal powder, powder magnetic core, and electronic component - Google Patents

Soft magnetic metal powder, powder magnetic core, and electronic component Download PDF

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WO2024143050A1
WO2024143050A1 PCT/JP2023/045347 JP2023045347W WO2024143050A1 WO 2024143050 A1 WO2024143050 A1 WO 2024143050A1 JP 2023045347 W JP2023045347 W JP 2023045347W WO 2024143050 A1 WO2024143050 A1 WO 2024143050A1
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soft magnetic
powder
magnetic metal
coating
coating portion
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French (fr)
Japanese (ja)
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智子 森
和宏 吉留
裕之 松元
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Tdk株式会社
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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
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/24—Magnetic cores
    • H01F27/255—Magnetic cores made from particles

Definitions

  • the present invention relates to soft magnetic metal powders, dust cores, and electronic components.
  • This soft magnetic alloy has good soft magnetic properties, including a high saturation magnetic flux density compared to commercially available Fe amorphous alloys.
  • Patent Document 2 describes metal particles in which an insulating layer containing silicon and oxygen is formed on the surface of the metal magnetic particles, and an insulating layer containing phosphorus is formed on top of that, improving the insulation between the metal particles.
  • the present invention was made in consideration of these circumstances, and its purpose is to provide a soft magnetic metal powder that has high powder resistance while maintaining good soft magnetic properties, and to provide a dust core and electronic component that has excellent DC bias characteristics while maintaining good soft magnetic properties in order to accommodate the miniaturization of magnetic elements.
  • the powder resistance can be improved, and the DC superposition characteristics of the powder core and electronic components obtained using the soft magnetic metal powder are improved. Furthermore, the magnetic properties such as magnetic permeability are also excellent.
  • the reason why the DC superposition characteristics are improved is not necessarily clear, but it is thought that this is because the coating can effectively protect the soft magnetic metal particles even if pressure is applied to the powder when applying pressure to the soft magnetic metal powder to mold it.
  • the adhesion of the coating is improved in this soft magnetic metal powder, and damage to the coating is reduced, and it is possible to provide a powder core and electronic components with excellent DC superposition characteristics and voltage resistance characteristics.
  • the relationships 1.1 ⁇ Fe1/Fe2 ⁇ 34.0 and 1.1 ⁇ Fe3/Fe2 ⁇ 41.0 are satisfied.
  • the powder resistivity of the soft magnetic powder is further improved.
  • the relationships 1.2 ⁇ Fe1/Fe2 ⁇ 32.0 and 1.2 ⁇ Fe3/Fe2 ⁇ 35.0 are further satisfied.
  • the powder resistivity of the soft magnetic powder is further improved.
  • the relationships 1.7 ⁇ Fe1/Fe2 ⁇ 20.0 and 1.3 ⁇ Fe3/Fe2 ⁇ 20.0 are further satisfied.
  • the powder resistivity of the soft magnetic powder is further improved.
  • the second coating portion has a lower Fe concentration than the Si concentration, and the first coating portion has a higher Fe concentration than the Si concentration.
  • the electronic component contains any of the soft magnetic metal powders described above.
  • FIG. 4A is a graph showing the results of EELS analysis performed along line IVA-IVA shown in FIG. 2, illustrating the element concentration profile versus distance from the particle center.
  • FIG. 4B is a graph showing an element concentration profile versus distance from the particle center for a soft magnetic metal powder according to another embodiment of the present invention, similar to FIG. 4A.
  • the material of the soft magnetic metal particles is not particularly limited as long as it contains Fe and exhibits soft magnetism.
  • materials containing Fe and exhibiting soft magnetism include pure iron, Fe-based alloys, Fe-Si-based alloys, Fe-Al-based alloys, Fe-Ni-based alloys, Fe-Co-based alloys, Fe-Si-Al-based alloys, Fe-Si-Cr-based alloys, Fe-Ni-Si-Co-based alloys, Fe-based amorphous alloys, Fe-Co-based amorphous alloys, Fe-based nanocrystalline alloys, and Fe-Co-based amorphous alloys.
  • the soft magnetic metal particles contain Si
  • the Si content in the particles is preferably 0.5 atomic % or more and 20 atomic % or less.
  • the average crystallite size of the soft magnetic metal particles composed of an Fe-based nanocrystalline alloy is preferably 1 nm or more and 50 nm or less, and more preferably 5 nm or more and 30 nm or less.
  • Fe-based nanocrystalline alloys include Fe-Nb-B system, Fe-Co-Nb-B system, Fe-Si-Nb-B-Cu system, Fe-Co-Si-Nb-B-Cu system, Fe-Si-P-B-Cu system, Fe-Co-Si-P-B system, etc.
  • the coating portion 10 of this embodiment has, from the surface of the soft magnetic metal particle 2 toward the outside, a first coating portion 11, a second coating portion 12, and a third coating portion 13, in this order.
  • the first coating portion 11 covers the surface of the soft magnetic metal particle 2
  • the second coating portion 12 covers the surface of the first coating portion 11
  • the third coating portion 13 covers the surface of the second coating portion 12.
  • Fe is contained in the first coating portion 11 at preferably 55 atomic % or more, more preferably 65 atomic % or more, even more preferably 68 atomic % or more, and even more preferably 75 atomic % or more, based on 100 atomic % of the total amount of elements excluding oxygen.
  • the first coating portion 11 may contain elements other than Fe and O, such as elements constituting soft magnetic powder, and may contain other elements such as one or more of Si, Cu, Cr, B, Al, Ni, Co, and P.
  • the other elements may be contained in the first coating portion 11 in the form of a complex oxide with Fe, or may be contained in the first coating portion 11 as an oxide other than iron oxide or other compound.
  • the second covering portion 12 is formed continuously with the first covering portion 11.
  • the second covering portion contains an oxide of Si.
  • the oxide of Si may exist as an amorphous SiO2 , or may exist as a crystalline or amorphous complex oxide with other elements.
  • the first coating portion 11 and the second coating portion 12 are configured to satisfy the relationship Fe1>Fe2.
  • the relationship 1.1 ⁇ Fe1/Fe2 ⁇ 34.0 is satisfied, more preferably 1.2 ⁇ Fe1/Fe2 ⁇ 32.0, and even more preferably 1.7 ⁇ Fe1/Fe2 ⁇ 20.0 is satisfied.
  • the powder resistance of the soft magnetic powder is further improved.
  • the second covering portion 12 may also contain other elements, as in the first covering portion 11.
  • the third coating portion 13 is preferably formed continuously with the second coating portion 12 and has a different composition ratio from that of the second coating portion.
  • the second coating portion 12 is mainly composed of an oxide having a low Fe content
  • the third coating portion 13 is composed of an oxide having a higher Fe content than the second coating portion.
  • the relationship 35.0 ⁇ Fe3 ⁇ 95.0 is satisfied, more preferably 37.0 ⁇ Fe3 ⁇ 93.0, even more preferably 40 ⁇ Fe3 ⁇ 92.0, and even more preferably 55.0 ⁇ Fe3 ⁇ 70.0 is satisfied.
  • the powder resistance of the soft magnetic powder is further improved.
  • the third covering portion 13 may also contain other elements, as in the first covering portion 11.
  • the dust core 100 can be manufactured using the soft magnetic metal powder described above. There are no particular limitations on the specific manufacturing method, and any known method can be used. First, a soft magnetic metal powder containing soft magnetic metal particles forming a coating portion is mixed with a known resin as a binder to obtain a mixture. If necessary, the resulting mixture may be made into a granulated powder. The mixture or granulated powder is then filled into a mold and compression molded to obtain a molded body having the shape of the dust core to be manufactured.
  • the powder resistance of the soft magnetic powder is further improved when the range is 35.0 ⁇ Fe3 ⁇ 95.0, more preferably 37.0 ⁇ Fe3 ⁇ 93.0, even more preferably 40.0 ⁇ Fe3 ⁇ 92.0, and even more preferably 55.0 ⁇ Fe3 ⁇ 70.0.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Dispersion Chemistry (AREA)
  • Soft Magnetic Materials (AREA)
  • Powder Metallurgy (AREA)

Abstract

[Problem] To provide: a soft magnetic metal powder having high powder resistance while maintaining good soft magnetic properties; a powder magnetic core having excellent DC superposition characteristics and maintaining good soft magnetic characteristics; and an electronic component. [Solution] This soft magnetic metal powder has soft magnetic metal particles containing Fe. The surface of the soft magnetic metal particles is covered by a coating. The coating has, at least: a first coating section; a second coating section; and a third coating section, in this order, from the surface of the soft magnetic metal particle toward the outside. The relationships Fe1>Fe2 and Fe3>Fe2 are satisfied when the concentration of Fe in the first coating section is Fe1, the concentration of Fe in the second coating section is Fe2, and the concentration of Fe in the third coating section is Fe3.

Description

軟磁性金属粉末、圧粉磁心および電子部品Soft magnetic metal powders, dust cores and electronic components
　本発明は、軟磁性金属粉末、圧粉磁心および電子部品に関する。 The present invention relates to soft magnetic metal powders, dust cores, and electronic components.
　近年、電子・情報・通信機器などにおいて、低消費電力化および高効率化が求められている。さらに、低炭素化社会へ向け、上記の要求が一層強くなっている。そのため、電子・情報・通信機器などの電源回路にも、エネルギー損失の低減や電源効率の向上が求められており、磁性素子においてはより一層の小型化が求められている。そして、電源回路に使用される磁性素子の磁心にはコアロス（磁心損失）の低減や小型化に対応すべく飽和磁束密度の向上などが求められている。 In recent years, there has been a demand for lower power consumption and higher efficiency in electronic, information, and communication devices. Furthermore, these demands are becoming even stronger as we move towards a low-carbon society. As a result, there is a demand for reduced energy loss and improved power efficiency in the power supply circuits of electronic, information, and communication devices, and there is a demand for magnetic elements to be even more compact. There is also a demand for the magnetic cores of the magnetic elements used in power supply circuits to reduce core loss (magnetic core loss) and improve saturation magnetic flux density to accommodate miniaturization.
　たとえば下記の特許文献１には、Ｆｅ－Ｂ－Ｍ（Ｍ＝Ｔｉ，Ｚｒ，Ｈｆ，Ｖ，Ｎｂ，Ｔａ，Ｍｏ，Ｗ）系の軟磁性合金が記載されている。この軟磁性合金は、市販のＦｅ非晶質合金と比べて高い飽和磁束密度を有するなど、良好な軟磁気特性を有する。 For example, the following Patent Document 1 describes a Fe-B-M (M = Ti, Zr, Hf, V, Nb, Ta, Mo, W) based soft magnetic alloy. This soft magnetic alloy has good soft magnetic properties, including a high saturation magnetic flux density compared to commercially available Fe amorphous alloys.
　また、下記の特許文献２では、金属磁性粒子表面にシリコンと酸素を含む絶縁層を形成し、その上にリンを含む絶縁層を有する金属粒子が記載されており、金属粒子間の絶縁性を向上させている。 In addition, the following Patent Document 2 describes metal particles in which an insulating layer containing silicon and oxygen is formed on the surface of the metal magnetic particles, and an insulating layer containing phosphorus is formed on top of that, improving the insulation between the metal particles.
　しかし、現在では、車等における自動運転等の発展で磁性素子において一層の耐電圧特性が求められており、磁性素子に使用される磁性粉末においても良好な軟磁気特性を有しつつ、さらに粉体抵抗が高い軟磁性粉末が求められている。 However, with the current development of autonomous driving in automobiles and other vehicles, there is a demand for magnetic elements with even higher voltage resistance, and there is a demand for soft magnetic powders used in magnetic elements that have good soft magnetic properties while also having high powder resistance.
特許第３３４２７６７号公報Patent No. 3342767 特開２０１７－３４２２８号公報JP 2017-34228 A
　本発明は、このような実状に鑑みてなされ、その目的は、良好な軟磁気特性を保ちながら粉体抵抗の高い軟磁性金属粉末を提供すること、ならびに磁性素子の小型化に対応するべく良好な軟磁気特性を保ちながら直流重畳特性に優れた圧粉磁心および電子部品を提供することである。 The present invention was made in consideration of these circumstances, and its purpose is to provide a soft magnetic metal powder that has high powder resistance while maintaining good soft magnetic properties, and to provide a dust core and electronic component that has excellent DC bias characteristics while maintaining good soft magnetic properties in order to accommodate the miniaturization of magnetic elements.
　上記目的を達成するために、本発明に係る軟磁性金属粉末は、
Ｆｅを含む軟磁性金属粒子を有する軟磁性金属粉末であって、
前記軟磁性金属粒子の表面は被覆部により覆われており、
前記被覆部は、前記軟磁性金属粒子の表面から外側に向かって、少なくとも第１の被覆部と、第２の被覆部と、第３の被覆部とをこの順で有し、
前記第１の被覆部におけるＦｅの濃度をＦｅ１、前記第２の被覆部におけるＦｅの濃度をＦｅ２、前記第３の被覆部におけるＦｅの濃度をＦｅ３とした場合に、
Ｆｅ１＞Ｆｅ２およびＦｅ３＞Ｆｅ２の関係を満足する。 In order to achieve the above object, the soft magnetic metal powder according to the present invention comprises:
A soft magnetic metal powder having soft magnetic metal particles containing Fe,
The surface of the soft magnetic metal particle is covered with a coating portion,
The coating portion has at least a first coating portion, a second coating portion, and a third coating portion in this order from the surface of the soft magnetic metal particle toward the outside,
When the concentration of Fe in the first coating portion is Fe1, the concentration of Fe in the second coating portion is Fe2, and the concentration of Fe in the third coating portion is Fe3,
The relationships Fe1>Fe2 and Fe3>Fe2 are satisfied.
　この軟磁性金属粉末では、Ｆｅ１＞Ｆｅ２およびＦｅ３＞Ｆｅ２とすることで、粉体抵抗を向上させることができると共に、軟磁性金属粉末を用いて得られる圧粉磁心および電
子部品の直流重畳特性が向上する。さらに、透磁率などの磁気特性にも優れている。直流重畳特性が向上する理由としては、必ずしも明らかではないが、たとえば軟磁性金属粉末に圧力を加えて成形する際に粉末に圧力が印加されても被覆部が軟磁性金属粒子を有効に保護することができるからではないかと考えられる。また、この軟磁性金属粉末では被覆部の密着性が向上していると考えられ、被覆部の破損が低減され、直流重畳特性や耐電圧特性に優れた圧粉磁心および電子部品を提供することができる。 In this soft magnetic metal powder, by making Fe1>Fe2 and Fe3>Fe2, the powder resistance can be improved, and the DC superposition characteristics of the powder core and electronic components obtained using the soft magnetic metal powder are improved. Furthermore, the magnetic properties such as magnetic permeability are also excellent. The reason why the DC superposition characteristics are improved is not necessarily clear, but it is thought that this is because the coating can effectively protect the soft magnetic metal particles even if pressure is applied to the powder when applying pressure to the soft magnetic metal powder to mold it. In addition, it is thought that the adhesion of the coating is improved in this soft magnetic metal powder, and damage to the coating is reduced, and it is possible to provide a powder core and electronic components with excellent DC superposition characteristics and voltage resistance characteristics.
　好ましくは１．１≦Ｆｅ１／Ｆｅ２≦３４．０　かつ　１．１≦Ｆｅ３／Ｆｅ２≦４１．０の関係をさらに満足する。このような範囲にあるときに、軟磁性粉末の粉体抵抗がさらに向上する。 Preferably, the relationships 1.1≦Fe1/Fe2≦34.0 and 1.1≦Fe3/Fe2≦41.0 are satisfied. When these ranges are satisfied, the powder resistivity of the soft magnetic powder is further improved.
　好ましくは、１．２≦Ｆｅ１／Ｆｅ２≦３２．０　かつ　１．２≦Ｆｅ３／Ｆｅ２≦３５．０の関係をさらに満足する。このような範囲にあるときに、軟磁性粉末の粉体抵抗がさらに向上する。 Preferably, the relationships 1.2≦Fe1/Fe2≦32.0 and 1.2≦Fe3/Fe2≦35.0 are further satisfied. When these ranges are satisfied, the powder resistivity of the soft magnetic powder is further improved.
　好ましくは、１．７≦Ｆｅ１／Ｆｅ２≦２０．０　かつ　１．３≦Ｆｅ３／Ｆｅ２≦２０．０の関係をさらに満足する。このような範囲にあるときに、軟磁性粉末の粉体抵抗がさらに向上する。 Preferably, the relationships 1.7≦Fe1/Fe2≦20.0 and 1.3≦Fe3/Fe2≦20.0 are further satisfied. When these ranges are satisfied, the powder resistivity of the soft magnetic powder is further improved.
　好ましくは、前記第２の被覆部では、Ｆｅの濃度がＳｉの濃度よりも低く、前記第１の被覆部では、Ｆｅの濃度がＳｉの濃度よりも高い。 Preferably, the second coating portion has a lower Fe concentration than the Si concentration, and the first coating portion has a higher Fe concentration than the Si concentration.
　第１の被覆部、第２の被覆部および第３の被覆部を有する被覆部の平均厚みは、特に限定されないが、好ましくは５～２５０ｎｍ程度に薄く、均一な厚みの膜であることが好ましい。被覆部の厚みにおいては薄い場合は圧粉磁心の透磁率が上がりやすく、また厚い場合は耐電圧特性が向上する。これら被覆部の厚みは磁性素子の設計により制御が可能である。本発明の一観点に係る軟磁性金属粉末では、従来と比較して、被覆部の厚みが同じ場合、粉末抵抗が高く制御できる。 The average thickness of the coating portion having the first coating portion, the second coating portion, and the third coating portion is not particularly limited, but is preferably a thin, uniform film of about 5 to 250 nm. If the coating portion is thin, the magnetic permeability of the powder core is likely to increase, and if it is thick, the voltage resistance characteristics improve. The thickness of these coating portions can be controlled by the design of the magnetic element. With the soft magnetic metal powder according to one aspect of the present invention, the powder resistance can be controlled to be high when the coating portion has the same thickness, compared to conventional cases.
　好ましくは、圧粉磁心は、上記のいずれかに記載の軟磁性金属粉末を有する。 Preferably, the powder magnetic core contains any of the soft magnetic metal powders described above.
上記のいずれかに記載の軟磁性金属粉末を用いて圧粉磁心を作製した場合、同じ被覆部厚みを有する従来の軟磁性粉末と比較して直流重畳特性を良好にすることが可能である。 When a dust core is produced using any of the soft magnetic metal powders described above, it is possible to improve the DC bias characteristics compared to conventional soft magnetic powders having the same coating thickness.
　好ましくは、電子部品は、上記のいずれかに記載の軟磁性金属粉末を有する。 Preferably, the electronic component contains any of the soft magnetic metal powders described above.
図１Ａは、本発明の一実施形態に係る軟磁性金属粒子の断面模式図である。FIG. 1A is a schematic cross-sectional view of a soft magnetic metal particle according to one embodiment of the present invention. 図１Ｂは、本発明の別の実施形態に係る変形例を示す断面模式図である。FIG. 1B is a schematic cross-sectional view showing a modified example according to another embodiment of the present invention. 図１Ｃは、本発明のさらに別の実施形態に係る変形例を示す断面模式図である。FIG. 1C is a schematic cross-sectional view showing a modified example according to still another embodiment of the present invention. 図２は、図１に示すII部分を拡大して撮影したＨＡＡＤＦ－ＳＴＥＭ像である。FIG. 2 is an enlarged HAADF-STEM image of the portion II shown in FIG. 図３Ａは、本発明の一実施形態に係る圧粉磁心の断面模式図である。FIG. 3A is a schematic cross-sectional view of a powder magnetic core according to one embodiment of the present invention. 図３Ｂは、図３Ａに示す圧粉磁心の変形例を示す断面模式図である。FIG. 3B is a schematic cross-sectional view showing a modification of the powder magnetic core shown in FIG. 3A. 図３Ｃは、図３Ａに示す圧粉磁心のさらに別の変形例を示す断面模式図である。FIG. 3C is a schematic cross-sectional view showing yet another modified example of the powder magnetic core shown in FIG. 3A. 図４Ａは、図２に示すIVＡ－IVＡ線に沿ってＥＥＬＳ分析を行った結果を示し、粒子中心部からの距離に対する元素濃度プロファイルを示すグラフである。FIG. 4A is a graph showing the results of EELS analysis performed along line IVA-IVA shown in FIG. 2, illustrating the element concentration profile versus distance from the particle center. 図４Ｂは、本発明の他の実施例に係る軟磁性金属粉末について、図４Ａと同様にして粒子中心部からの距離に対する元素濃度プロファイルを示すグラフである。FIG. 4B is a graph showing an element concentration profile versus distance from the particle center for a soft magnetic metal powder according to another embodiment of the present invention, similar to FIG. 4A.
　以下、本発明の実施形態を説明する。 The following describes an embodiment of the present invention.
　第１実施形態
（軟磁性金属粉末）
本実施形態に係る軟磁性金属粉末は、図１Ａに示すように、複数の被覆粒子１を含む。本実施形態では、被覆粒子１は、軟磁性金属粒子２の表面に被覆部１０を持つ被覆粒子であり、軟磁性金属粉末に含まれる粒子の個数割合を１００％とした場合、被覆粒子１の個数割合が８０％以上であることが好ましく、５０％以上であることが好ましい。なお、軟磁性金属粒子２の形状は特に制限されないが、好ましくは球形である。 First embodiment (soft magnetic metal powder)
As shown in Fig. 1A, the soft magnetic metal powder according to this embodiment includes a plurality of coated particles 1. In this embodiment, the coated particles 1 are coated particles having a coating portion 10 on the surface of the soft magnetic metal particle 2, and when the number ratio of the particles contained in the soft magnetic metal powder is 100%, the number ratio of the coated particles 1 is preferably 80% or more, and more preferably 50% or more. The shape of the soft magnetic metal particle 2 is not particularly limited, but is preferably spherical.
　本実施形態に係る軟磁性金属粉末の平均粒子径（Ｄ５０）は、用途および材質に応じて選択すればよい。本実施形態では、軟磁性金属粉末の平均粒子径（Ｄ５０）は、０．３～１００μｍの範囲内であることが好ましい。軟磁性金属粉末の平均粒子径を上記の範囲内とすることにより、十分な成形性あるいは所定の磁気特性を維持することが容易となる。平均粒子径の測定方法としては、特に制限されないが、レーザー回折散乱法を用いることが好ましい。 The average particle diameter (D50) of the soft magnetic metal powder according to this embodiment may be selected according to the application and material. In this embodiment, the average particle diameter (D50) of the soft magnetic metal powder is preferably within the range of 0.3 to 100 μm. By setting the average particle diameter of the soft magnetic metal powder within the above range, it becomes easier to maintain sufficient moldability or predetermined magnetic properties. There are no particular limitations on the method for measuring the average particle diameter, but it is preferable to use a laser diffraction scattering method.
　本実施形態では、軟磁性金属粒子の材質は、Ｆｅを含み軟磁性を示す材料であれば特に制限されない。Ｆｅを含み軟磁性を示す材料としては、純鉄、Ｆｅ系合金、Ｆｅ－Ｓｉ系合金、Ｆｅ－Ａｌ系合金、Ｆｅ－Ｎｉ系合金、Ｆｅ－Ｃｏ系合金、Ｆｅ－Ｓｉ－Ａｌ系合金、Ｆｅ－Ｓｉ－Ｃｒ系合金、Ｆｅ－Ｎｉ－Ｓｉ－Ｃｏ系合金、Ｆｅ系非晶質合金、Ｆｅ-Ｃｏ系非晶質合金、Ｆｅ系ナノ結晶合金、Ｆｅ-Ｃｏ系非晶質合金、などが例示される。軟磁性金属粒子がＳｉを含む場合には、粒子中には、Ｓｉが好ましくは０．５原子％以上、２０原子％以下である。 In this embodiment, the material of the soft magnetic metal particles is not particularly limited as long as it contains Fe and exhibits soft magnetism. Examples of materials containing Fe and exhibiting soft magnetism include pure iron, Fe-based alloys, Fe-Si-based alloys, Fe-Al-based alloys, Fe-Ni-based alloys, Fe-Co-based alloys, Fe-Si-Al-based alloys, Fe-Si-Cr-based alloys, Fe-Ni-Si-Co-based alloys, Fe-based amorphous alloys, Fe-Co-based amorphous alloys, Fe-based nanocrystalline alloys, and Fe-Co-based amorphous alloys. When the soft magnetic metal particles contain Si, the Si content in the particles is preferably 0.5 atomic % or more and 20 atomic % or less.
　Ｆｅ系非晶質合金は、合金を構成する原子の配列がランダムであり、合金全体として結晶性を有していない非晶質合金である。Ｆｅ系非晶質合金としては、たとえば、Ｆｅ－Ｓｉ－Ｂ系、Ｆｅ－Ｓｉ－Ｂ－Ｃｒ－Ｃ系、Ｆｅ―Ｃｏ－Ｓｉ－Ｂ－Ｃｒ－Ｃ系等が例示される。 Fe-based amorphous alloys are amorphous alloys in which the atoms that make up the alloy are arranged randomly and the alloy as a whole does not have crystallinity. Examples of Fe-based amorphous alloys include Fe-Si-B, Fe-Si-B-Cr-C, and Fe-Co-Si-B-Cr-C systems.
　Ｆｅ系ナノ結晶合金は、Ｆｅ系非晶質合金、または、初期微結晶が非晶質中に存在するナノヘテロ構造を有するＦｅ系合金を熱処理することにより、非晶質中にナノメートルオーダーの微結晶が析出した合金である。 An Fe-based nanocrystalline alloy is an alloy in which nanometer-sized microcrystals are precipitated in the amorphous phase by heat treating an Fe-based amorphous alloy or an Fe-based alloy with a nanoheterostructure in which primary microcrystals exist in the amorphous phase.
　本実施形態では、Ｆｅ系ナノ結晶合金から構成される軟磁性金属粒子における平均結晶子径は、１ｎｍ以上５０ｎｍ以下であることが好ましく、５ｎｍ以上３０ｎｍ以下であることがより好ましい。Ｆｅ系ナノ結晶合金としては、たとえば、Ｆｅ－Ｎｂ－Ｂ系、Ｆｅ－Ｃｏ－Ｎｂ－Ｂ系、Ｆｅ－Ｓｉ－Ｎｂ－Ｂ－Ｃｕ系、Ｆｅ－Ｃｏ－Ｓｉ－Ｎｂ－Ｂ－Ｃｕ系、Ｆｅ－Ｓｉ－Ｐ－Ｂ－Ｃｕ系、Ｆｅ－Ｃｏ-Ｓｉ－Ｐ－Ｂ系等が例示される。 In this embodiment, the average crystallite size of the soft magnetic metal particles composed of an Fe-based nanocrystalline alloy is preferably 1 nm or more and 50 nm or less, and more preferably 5 nm or more and 30 nm or less. Examples of Fe-based nanocrystalline alloys include Fe-Nb-B system, Fe-Co-Nb-B system, Fe-Si-Nb-B-Cu system, Fe-Co-Si-Nb-B-Cu system, Fe-Si-P-B-Cu system, Fe-Co-Si-P-B system, etc.
　また、本実施形態では、軟磁性金属粉末は、材質が同じ軟磁性金属粒子のみを含んでいてもよいし、材質が異なる軟磁性金属粒子が混在していてもよい。たとえば、軟磁性金属粉末は、複数のＦｅ系合金粒子と、複数のＦｅ－Ｓｉ系合金粒子との混合物であってもよい。なお、異なる材質とは、金属または合金を構成する元素が異なる場合、構成する元素が同じであってもその組成が異なる場合、結晶系が異なる場合等が例示される。 In addition, in this embodiment, the soft magnetic metal powder may contain only soft magnetic metal particles of the same material, or may contain a mixture of soft magnetic metal particles of different materials. For example, the soft magnetic metal powder may be a mixture of a plurality of Fe-based alloy particles and a plurality of Fe-Si-based alloy particles. Examples of different materials include metals or alloys made of different elements, metals or alloys made of the same elements but with different compositions, and metals with different crystal systems.
　図１Ａに示すように、本実施形態の被覆部１０は、軟磁性金属粒子２の表面から外側に向かって、第１の被覆部１１と、第２の被覆部１２と、第３の被覆部１３とを、この順で有する。第１の被覆部１１は、軟磁性金属粒子２の表面を覆っており、第２の被覆部１２は、第１の被覆部１１の表面を覆っており、第３の被覆部１３は、第２の被覆部１２の表面を覆っている。 As shown in FIG. 1A, the coating portion 10 of this embodiment has, from the surface of the soft magnetic metal particle 2 toward the outside, a first coating portion 11, a second coating portion 12, and a third coating portion 13, in this order. The first coating portion 11 covers the surface of the soft magnetic metal particle 2, the second coating portion 12 covers the surface of the first coating portion 11, and the third coating portion 13 covers the surface of the second coating portion 12.
　本実施形態では、被覆部が表面を覆っているとは、被覆部が表面に接触して接触した部分を覆うように固定されている形態をいうが、被覆部が表面に形成される方法は特に限定されない。また、軟磁性金属粒子２または被覆部の表面を被覆する被覆部は、粒子の表面の少なくとも一部を覆っていればよいが、表面の全体を覆っていることが好ましい。さらに、被覆部は粒子の表面を連続的に覆っていてもよいし、断続的に覆っていてもよい。 In this embodiment, the coating covering the surface refers to a form in which the coating comes into contact with the surface and is fixed so as to cover the contacted portion, but the method by which the coating is formed on the surface is not particularly limited. Furthermore, the coating that covers the surface of the soft magnetic metal particle 2 or the coating may cover at least a portion of the surface of the particle, but it is preferable that it covers the entire surface. Furthermore, the coating may cover the surface of the particle continuously or intermittently.
　第１の被覆部１１は、好ましくは、酸化物で構成してある。本実施形態では、第１の被覆部１１は、Ｆｅの酸化物を含んでいる。鉄酸化物は、ＦｅＯ、Ｆｅ2Ｏ3、Ｆｅ3Ｏ4などの結晶として存在してもよいし、その他の元素との複合酸化物の結晶または非晶質として存在していてもよい。 The first covering portion 11 is preferably made of an oxide. In this embodiment, the first covering portion 11 contains an oxide of Fe. The iron oxide may exist as a crystal such as FeO, Fe2O3 , or Fe3O4 , or may exist as a crystal or amorphous complex oxide with other elements.
　本実施形態では、Ｆｅは、酸素を除いた元素の合計量１００原子％に対して、好ましくは５５原子％以上、さらに好ましくは６５原子％以上、さらに好ましくは６８原子％以上、さらに好ましくは７５原子％以上で、第１の被覆部１１に含まれる。第１の被覆部１１には、ＦｅおよびＯ以外の元素として、たとえば軟磁性粉末を構成する元素を含んでいてもよく、Ｓｉ、Ｃｕ、Ｃｒ、Ｂ、Ａｌ、Ｎｉ、Ｃｏ、またはＰなどのいずれか一つ以上で、その他の元素が含まれていてもよい。その他の元素は、Ｆｅとの複合酸化物の形態で、第１の被覆部１１に含まれていてもよいし、鉄酸化物とは別の酸化物あるいはその他の化合物として第１の被覆部１１に含まれていてもよい。 In this embodiment, Fe is contained in the first coating portion 11 at preferably 55 atomic % or more, more preferably 65 atomic % or more, even more preferably 68 atomic % or more, and even more preferably 75 atomic % or more, based on 100 atomic % of the total amount of elements excluding oxygen. The first coating portion 11 may contain elements other than Fe and O, such as elements constituting soft magnetic powder, and may contain other elements such as one or more of Si, Cu, Cr, B, Al, Ni, Co, and P. The other elements may be contained in the first coating portion 11 in the form of a complex oxide with Fe, or may be contained in the first coating portion 11 as an oxide other than iron oxide or other compound.
　第２の被覆部１２は、第１の被覆部１１に連続して形成してある。本実施形態では、第２の被覆部はＳｉの酸化物を含んでいる。Ｓｉの酸化物は、ＳｉＯ2の非晶質として存在
していてもよいし、その他の元素との複合酸化物の結晶または非晶質として存在していてもよい。 The second covering portion 12 is formed continuously with the first covering portion 11. In this embodiment, the second covering portion contains an oxide of Si. The oxide of Si may exist as an amorphous SiO2 , or may exist as a crystalline or amorphous complex oxide with other elements.
　また第１の被覆部におけるＦｅの濃度（原子％）をＦｅ１、第２の被覆部におけるＦｅの濃度（原子％）をＦｅ２とした場合に、Ｆｅ１＞Ｆｅ２の関係を満足するように、第１の被覆部１１および第２の被覆部１２が構成してある。好ましくは、１．１≦Ｆｅ１／Ｆｅ２≦３４．０、さらに好ましくは１．２≦Ｆｅ１／Ｆｅ２≦３２．０、さらに好ましくは１．７≦Ｆｅ１／Ｆｅ２≦２０．０の関係を満足する。このような範囲にあるときに、軟磁性粉末の粉体抵抗がさらに向上する。 Furthermore, when the Fe concentration (atomic %) in the first coating portion is Fe1 and the Fe concentration (atomic %) in the second coating portion is Fe2, the first coating portion 11 and the second coating portion 12 are configured to satisfy the relationship Fe1>Fe2. Preferably, the relationship 1.1≦Fe1/Fe2≦34.0 is satisfied, more preferably 1.2≦Fe1/Fe2≦32.0, and even more preferably 1.7≦Fe1/Fe2≦20.0 is satisfied. When it is within such a range, the powder resistance of the soft magnetic powder is further improved.
　また好ましくは、２．０≦Ｆｅ２≦６５．０、さらに好ましくは４．０≦Ｆｅ２≦５０．０、さらに好ましくは５．０≦Ｆｅ２≦３０、さらに好ましくは９．０≦Ｆｅ２≦１８．０の関係をさらに満足する。このような範囲にあるときに、軟磁性粉末の粉体抵抗がさらに向上する。なお、第２の被覆部１２においても、第１の被覆部１１と同様に、その他の元素が含まれていてもよい。 Furthermore, it is preferable that the relationship 2.0≦Fe2≦65.0 is satisfied, more preferably 4.0≦Fe2≦50.0, even more preferably 5.0≦Fe2≦30, and even more preferably 9.0≦Fe2≦18.0 is satisfied. When it is within such a range, the powder resistance of the soft magnetic powder is further improved. Note that the second covering portion 12 may also contain other elements, as in the first covering portion 11.
　第３の被覆部１３は、第２の被覆部１２に連続して形成してあり、しかも第２の被覆部とは異なる組成比であることが好ましい。たとえば第２の被覆部１２が主として、Ｆｅ含有量が小さく、第３の被覆部１３は、第２の被覆部よりもＦｅの含有割合が多い酸化物で構成してあることが好ましい。 The third coating portion 13 is preferably formed continuously with the second coating portion 12 and has a different composition ratio from that of the second coating portion. For example, it is preferable that the second coating portion 12 is mainly composed of an oxide having a low Fe content, and the third coating portion 13 is composed of an oxide having a higher Fe content than the second coating portion.
　たとえば第２の被覆部におけるＦｅの濃度（原子％）をＦｅ２、第３の被覆部における
Ｆｅの濃度（原子％）をＦｅ３とした場合に、Ｆｅ３＞Ｆｅ２の関係を満足するように、第２の被覆部１２および第３の被覆部１３が構成してある。好ましくは、１．１≦Ｆｅ３／Ｆｅ２≦４１．０、さらに好ましくは１．２≦Ｆｅ３／Ｆｅ２≦３５．０、さらに好ましくは１．３≦Ｆｅ３／Ｆｅ２≦２０．０の関係をさらに満足する。このような範囲にあるときに、軟磁性粉末の粉体抵抗がさらに向上する。 For example, when the Fe concentration (atomic %) in the second covering portion is Fe2 and the Fe concentration (atomic %) in the third covering portion is Fe3, the second covering portion 12 and the third covering portion 13 are configured to satisfy the relationship Fe3>Fe2. Preferably, the relationship 1.1≦Fe3/Fe2≦41.0 is satisfied, more preferably 1.2≦Fe3/Fe2≦35.0, and even more preferably 1.3≦Fe3/Fe2≦20.0 is satisfied. When the relationship is within such a range, the powder resistivity of the soft magnetic powder is further improved.
　また好ましくは３５．０≦Ｆｅ３≦９５．０、さらに好ましくは３７．０≦Ｆｅ３≦９３．０、さらに好ましくは４０≦Ｆｅ３≦９２．０、さらに好ましくは５５．０≦Ｆｅ３≦７０．０の関係をさらに満足する。このような範囲にあるときに、軟磁性粉末の粉体抵抗がさらに向上する。なお、第３の被覆部１３においても、第１の被覆部１１と同様に、その他の元素が含まれていてもよい。 Furthermore, it is preferable that the relationship 35.0≦Fe3≦95.0 is satisfied, more preferably 37.0≦Fe3≦93.0, even more preferably 40≦Fe3≦92.0, and even more preferably 55.0≦Fe3≦70.0 is satisfied. When it is within such a range, the powder resistance of the soft magnetic powder is further improved. Note that the third covering portion 13 may also contain other elements, as in the first covering portion 11.
　第１の被覆部、第２の被覆部および第３の被覆部に含まれる成分は、透過型電子顕微鏡（Transmission Electron Microscope）を用いたエネルギー分散型Ｘ線分光法（Energy Dispersive X-ray Spectroscopy：EDS）による元素分析、電子エネルギー損失分光法（Electron Energy Loss Spectroscopy：EELS）による元素分析から同定することができる。 The components contained in the first coating part, the second coating part and the third coating part can be identified by elemental analysis using Energy Dispersive X-ray Spectroscopy (EDS) with a Transmission Electron Microscope and elemental analysis using Electron Energy Loss Spectroscopy (EELS).
　また、軟磁性金属粒子２と第１の被覆部１１との境界、第１の被覆部１１と第２の被覆部１２との境界、および第２の被覆部１２と第３の被覆部１３との境界は、たとえば図２に示すように、ＨＡＡＤＦ－ＳＴＥＭ（High-Angle Annular Dark Field Scanning TEM）像による明度の差異により判断することができる。なお、第１の被覆部１１に関しては、ＴＥＭ試料の厚み方向の重なりの影響で金属層の鉄と第２の被覆部１２の酸素が重なって見えている可能性も考えられるため、ＥＥＬＳスペクトルも確認し、ＦｅのLエッジ形状
が酸化物と同様になっているかでＦｅの酸化物が存在するかを確認することが好ましい。 The boundaries between the soft magnetic metal particles 2 and the first coating portion 11, the boundaries between the first coating portion 11 and the second coating portion 12, and the boundaries between the second coating portion 12 and the third coating portion 13 can be determined by the difference in brightness in a High-Angle Annular Dark Field Scanning TEM (HAADF-STEM) image, for example, as shown in Fig. 2. Regarding the first coating portion 11, it is possible that the iron of the metal layer and the oxygen of the second coating portion 12 are overlapping due to the influence of overlapping in the thickness direction of the TEM sample, so it is preferable to also check the EELS spectrum and confirm whether or not an oxide of Fe is present by checking whether the L edge shape of Fe is similar to that of an oxide.
　第１の被覆部１１、第２の被覆部１２および第３の被覆部１３を有する被覆部１０の平均厚みは、特に限定されないが、好ましくは５～２５０ｎｍ、さらに好ましくは６～１２５ｎｍ、さらに好ましくは１０ｎｍ～１１０ｎｍ程度に薄く、均一な厚みの膜であることが好ましい。本実施形態に係る軟磁性金属粉末では、被覆部１０の厚みが仮に５０ｎｍ以下、４０ｎｍ以下、３０ｎｍ以下であっても、１０の５乗以上、１０の６乗以上、１０の７乗以上あるいは１０の８乗以上の抵抗率（Ω・ｃｍ）を有する軟磁性金属粉末を得ることができる。 The average thickness of the coating 10, which includes the first coating 11, the second coating 12, and the third coating 13, is not particularly limited, but is preferably a thin, uniform film of 5 to 250 nm, more preferably 6 to 125 nm, and even more preferably 10 to 110 nm. With the soft magnetic metal powder according to this embodiment, even if the thickness of the coating 10 is 50 nm or less, 40 nm or less, or 30 nm or less, it is possible to obtain a soft magnetic metal powder having a resistivity (Ω·cm) of 10 to the power of 5 or more, 10 to the power of 6 or more, 10 to the power of 7 or more, or 10 to the power of 8 or more.
　なお、第１の被覆部１１の厚みは、特に制限されないが、本実施形態では、好ましくは０．８ｎｍ以上、さらに好ましくは１．１ｎｍ以上である。第２の被覆部１２の厚みは、特に制限されないが、本実施形態では、好ましくは１ｎｍ以上、さらに好ましくは１．７ｎｍ以上、さらに好ましくは２．４ｎｍ以上である。第３の被覆部１３の厚みは、特に制限されないが、本実施形態では、好ましくは１ｎｍ以上、さらに好ましくは１．５ｎｍ以上である。 The thickness of the first covering portion 11 is not particularly limited, but in this embodiment, it is preferably 0.8 nm or more, and more preferably 1.1 nm or more. The thickness of the second covering portion 12 is not particularly limited, but in this embodiment, it is preferably 1 nm or more, and more preferably 1.7 nm or more, and more preferably 2.4 nm or more. The thickness of the third covering portion 13 is not particularly limited, but in this embodiment, it is preferably 1 nm or more, and more preferably 1.5 nm or more.
　（軟磁性金属粉末の製造方法）
本実施形態では、被覆部が形成される前の軟磁性金属粉末は、公知の軟磁性金属粉末の製造方法と同様の方法を用いて得ることができる。具体的には、カルボニル法、噴霧熱分解法、ＣＶＤ法、ＰＶＤ法、ガスアトマイズ法、水アトマイズ法、回転ディスク法等を用いて製造することができる。また、単ロール法により得られる薄帯を機械的に粉砕して製造してもよい。また目的の粒子径にするため、気流分級や湿式分級、乾式分級などを用いてもよい。 (Method of manufacturing soft magnetic metal powder)
In this embodiment, the soft magnetic metal powder before the coating portion is formed can be obtained using a method similar to the known method for producing soft magnetic metal powder. Specifically, it can be produced using the carbonyl method, spray pyrolysis method, CVD method, PVD method, gas atomization method, water atomization method, rotating disk method, etc. Also, it may be produced by mechanically pulverizing a thin ribbon obtained by a single roll method. Also, air classification, wet classification, dry classification, etc. may be used to obtain the desired particle size.
　次に、軟磁性金属粒子に対して被覆部を形成する。被覆部を形成する方法としては、特に制限されず、公知の方法を採用することができる。軟磁性金属粒子に対して湿式処理を
行って被覆部を形成してもよいし、乾式処理を行って被覆部を形成してもよい。 Next, a coating is formed on the soft magnetic metal particles. The method for forming the coating is not particularly limited, and a known method can be used. The coating may be formed by performing a wet treatment on the soft magnetic metal particles, or may be formed by performing a dry treatment on the soft magnetic metal particles.
　粒子を構成する金属軟磁性材料がＦｅ系磁性材料の場合には、粒子の表面酸化により第１の被覆部１１を形成できる。第１の被覆部１１の形成は、弱い酸化雰囲気中で熱処理（第１の熱処理）することで行われる。熱処理条件は特に限定はされないが、たとえば低酸素濃度の雰囲気下、約３００～８００°Ｃで行うことができる。熱処理雰囲気を調整することで、第１の被覆部１１の厚みを制御できる。なお、Ｆｅを含有する溶液を金属磁性材料に噴霧し熱処理することでも、第１の被覆部１１を形成できる。 When the metallic soft magnetic material constituting the particles is an Fe-based magnetic material, the first coating portion 11 can be formed by oxidizing the surface of the particles. The first coating portion 11 is formed by heat treatment (first heat treatment) in a weakly oxidizing atmosphere. The heat treatment conditions are not particularly limited, but can be performed, for example, in an atmosphere with a low oxygen concentration at about 300 to 800°C. The thickness of the first coating portion 11 can be controlled by adjusting the heat treatment atmosphere. The first coating portion 11 can also be formed by spraying a solution containing Fe onto the metallic magnetic material and then heat treating it.
　第２の被覆部１２は、粉末スパッタ法、ゾルゲル法、メカノケミカルを利用したコーティング方法等により形成することができる。ゾルゲル法では、酸または塩基触媒条件下にて、たとえばＴＥＯＳなどのアルコキシシランを加水分解して、さらに縮合重合させることにより、軟磁性金属粒子の表面にＳｉリッチな第２の被覆部を形成させることができる。第２の被覆部１２の厚みは、アルコキシシランの量などにより調整することができる。 The second coating portion 12 can be formed by a powder sputtering method, a sol-gel method, a coating method using mechanochemicals, or the like. In the sol-gel method, an alkoxysilane such as TEOS is hydrolyzed under acid or base catalytic conditions, and then condensation polymerized to form a Si-rich second coating portion on the surface of the soft magnetic metal particles. The thickness of the second coating portion 12 can be adjusted by the amount of alkoxysilane, etc.
　第３の被覆部１３は、酸化雰囲気中での熱処理、あるいは第２の被覆部１２と同様に粉末スパッタ法等により形成することができる。酸化雰囲気中での熱処理では、第２の被覆部１２が形成された軟磁性金属粒子を酸化雰囲気中で所定の温度で熱処理（第２の熱処理）を行うことにより、軟磁性金属粒子を構成するＦｅが第２の被覆部１２を通り抜けて第２の被覆部１２の表面まで拡散し、表面で雰囲気中の酸素と結合して、Ｆｅの酸化物が形成される。このようにすることにより、第３の被覆部１３を形成することができる。軟磁性金属粒子を構成する他の金属元素が拡散しやすい元素である場合には、当該金属元素の酸化物も第３の被覆部１３に含まれる。第３の被覆部１３の厚みは、熱処理時間等により調整することができる。 The third coating portion 13 can be formed by heat treatment in an oxidizing atmosphere, or by powder sputtering, as in the case of the second coating portion 12. In the heat treatment in an oxidizing atmosphere, the soft magnetic metal particles on which the second coating portion 12 is formed are heat-treated (second heat treatment) at a predetermined temperature in an oxidizing atmosphere, so that the Fe constituting the soft magnetic metal particles passes through the second coating portion 12 and diffuses to the surface of the second coating portion 12, where it combines with oxygen in the atmosphere to form an oxide of Fe. In this way, the third coating portion 13 can be formed. If the other metal element constituting the soft magnetic metal particles is an element that is easily diffused, the oxide of that metal element is also included in the third coating portion 13. The thickness of the third coating portion 13 can be adjusted by the heat treatment time, etc.
　（実施形態のまとめ）
本実施形態の軟磁性金属粉末では、Ｆｅ１＞Ｆｅ２およびＦｅ３＞Ｆｅ２とすることで、粉体抵抗を向上させることができると共に、軟磁性金属粉末を用いて得られる圧粉磁心および電子部品の直流重畳特性が向上する。さらに、透磁率などの磁気特性にも優れている。直流重畳特性が向上する理由としては、必ずしも明らかではないが、たとえば軟磁性金属粉末に圧力を加えて成形する際に粉末に圧力が印加されても被覆部１０が軟磁性金属粒子２を有効に保護することができるからではないかと考えられる。また、この軟磁性金属粉末では被覆部１０の密着性が向上していると考えられ、被覆部１０の破損が低減され、直流重畳特性や耐電圧特性に優れた圧粉磁心および電子部品を提供することができる。 (Summary of the embodiment)
In the soft magnetic metal powder of this embodiment, by making Fe1>Fe2 and Fe3>Fe2, the powder resistance can be improved, and the DC superposition characteristics of the powder core and electronic components obtained using the soft magnetic metal powder are improved. Furthermore, the magnetic properties such as magnetic permeability are also excellent. The reason why the DC superposition characteristics are improved is not necessarily clear, but it is thought that this is because the coating portion 10 can effectively protect the soft magnetic metal particles 2 even if pressure is applied to the powder when applying pressure to the soft magnetic metal powder to mold it. In addition, it is thought that the adhesion of the coating portion 10 is improved in this soft magnetic metal powder, and damage to the coating portion 10 is reduced, and it is possible to provide a powder core and electronic components with excellent DC superposition characteristics and voltage resistance characteristics.
　本実施形態に係る軟磁性金属粉末では、被覆部の厚みは、特に限定されないが、好ましくは５～２５０ｎｍ、さらに好ましくは６～１２５ｎｍ、さらに好ましくは１０ｎｍ～１１０ｎｍ程度に薄い膜である。被覆部１０の厚みが仮に５０ｎｍ以下であっても、１０の５乗以上、１０の６乗以上、１０の７乗以上あるいは１０の８乗以上の抵抗率（Ω・ｃｍ）を有する軟磁性金属粉末を得ることができる。 In the soft magnetic metal powder according to this embodiment, the thickness of the coating is not particularly limited, but is preferably a thin film of about 5 to 250 nm, more preferably 6 to 125 nm, and even more preferably 10 nm to 110 nm. Even if the thickness of the coating 10 is 50 nm or less, it is possible to obtain a soft magnetic metal powder having a resistivity (Ω cm) of 10 to the power of 5 or more, 10 to the power of 6 or more, 10 to the power of 7 or more, or 10 to the power of 8 or more.
　第２実施形態
被覆部１０は、軟磁性金属粒子２の表面から外側に向かって、第１の被覆部１１、第２の被覆部１２、第３の被覆部１３の順で構成されていれば、第１の被覆部１１、第２の被覆部１２、第３の被覆部１３以外の被覆部を有していてもよい。 Second embodiment The coating part 10 may have coating parts other than the first coating part 11, the second coating part 12, and the third coating part 13, so long as the coating part 10 is configured in the order of the first coating part 11, the second coating part 12, and the third coating part 13 from the surface of the soft magnetic metal particle 2 toward the outside.
　たとえば、図１Ｂに示すように、軟磁性金属粒子２と第１の被覆部１１との間に第４の被覆部１４を有していてもよい。第４の被覆部１４は、Ｆｅを実質的に含まなくてもよく、あるいは、第１の被覆部よりもＦｅの含有量が少ない酸化物の層であってもよい。 For example, as shown in FIG. 1B, a fourth coating portion 14 may be present between the soft magnetic metal particle 2 and the first coating portion 11. The fourth coating portion 14 may be substantially free of Fe, or may be an oxide layer having a lower Fe content than the first coating portion.
　また、たとえば図１Ｃに示すように、第３の被覆部１３のさらに外側に、第５の被覆部１５を有していてもよい。第５の被覆部１５は、Ｆｅを実質的に含まなくてもよく、あるいは、第３の被覆部よりもＦｅの含有量が少ない酸化物の層であってもよい。 Furthermore, as shown in FIG. 1C, for example, a fifth coating portion 15 may be provided on the outer side of the third coating portion 13. The fifth coating portion 15 may be substantially free of Fe, or may be an oxide layer having a lower Fe content than the third coating portion.
　図１Ｂに示す第４の被覆部１４を形成するためには、たとえば第１の被覆部１１を形成する前に、必要に応じて内側被覆部（第４の被覆部１４）を形成する。内側被覆部は、粉末スパッタ法、ゾルゲル法、メカノケミカルを利用したコーティング方法等により形成することができる。たとえばアトマイズ法により金属磁性粒子を用意する場合には、アトマイズ時の乾燥雰囲気を調整することにより、内側被覆部を形成することができる。内側被覆部の厚みは、乾燥時のガス種やガス分圧等により調整することができる。 To form the fourth coating portion 14 shown in FIG. 1B, for example, an inner coating portion (fourth coating portion 14) is formed as necessary before forming the first coating portion 11. The inner coating portion can be formed by a powder sputtering method, a sol-gel method, a coating method using mechanochemistry, or the like. For example, when preparing metal magnetic particles by an atomization method, the inner coating portion can be formed by adjusting the drying atmosphere during atomization. The thickness of the inner coating portion can be adjusted by the type of gas and partial gas pressure during drying, etc.
　また、図１Ｃに示す第５の被覆部１５を形成するには、たとえば第３の被覆部１３を形成した後に、必要に応じて外側被覆部（第５の被覆部１５）を形成する。外側被覆部は、粉末スパッタ法、ゾルゲル法、メカノケミカルを利用したコーティング方法等により形成することができる。外側被覆部の厚みは、スパッタリング時間等により調整することができる。 To form the fifth coating portion 15 shown in FIG. 1C, for example, the third coating portion 13 is formed, and then an outer coating portion (fifth coating portion 15) is formed as necessary. The outer coating portion can be formed by a powder sputtering method, a sol-gel method, a coating method using mechanochemicals, or the like. The thickness of the outer coating portion can be adjusted by the sputtering time, etc.
　第３実施形態
（圧粉磁心）
図３Ａに示すように、本実施形態に係る圧粉磁心１００は、前述した第１または第２実施形態の軟磁性金属粉末を用いて形成され、所定の形状を有するように形成されていれば、その外形の形状は特に制限されない。本実施形態の圧粉磁心１００は、複数の被覆粒子１を含む軟磁性金属粉末と、結合剤としての樹脂（図示せず）とを含み、当該軟磁性金属粉末を構成する被覆粒子１同士が樹脂を介して結合することにより所定の形状に固定されている。 Third embodiment (powder core)
3A, the dust core 100 according to this embodiment is formed using the soft magnetic metal powder of the first or second embodiment described above, and the external shape is not particularly limited as long as it is formed to have a predetermined shape. The dust core 100 of this embodiment contains a soft magnetic metal powder containing a plurality of coated particles 1 and a resin (not shown) as a binder, and the coated particles 1 constituting the soft magnetic metal powder are fixed into a predetermined shape by being bonded to each other via the resin.
　圧粉磁心１００は、上記の軟磁性金属粉末を用いて製造することができる。具体的な製造方法としては、特に制限されず、公知の方法を採用することができる。まず、被覆部を形成した軟磁性金属粒子を含む軟磁性金属粉末と、結合剤としての公知の樹脂とを混合し、混合物を得る。また、必要に応じて、得られた混合物を造粒粉としてもよい。そして、混合物または造粒粉を金型内に充填して圧縮成形し、作製すべき圧粉磁心の形状を有する成形体を得る。 The dust core 100 can be manufactured using the soft magnetic metal powder described above. There are no particular limitations on the specific manufacturing method, and any known method can be used. First, a soft magnetic metal powder containing soft magnetic metal particles forming a coating portion is mixed with a known resin as a binder to obtain a mixture. If necessary, the resulting mixture may be made into a granulated powder. The mixture or granulated powder is then filled into a mold and compression molded to obtain a molded body having the shape of the dust core to be manufactured.
　得られた成形体に対して、たとえば５０～２００°Ｃで熱処理を行うことにより、樹脂が硬化し軟磁性金属粒子が樹脂を介して固定され、たとえば図３Ａに示す所定形状の圧粉磁心１００が得られる。得られた圧粉磁心に、ワイヤを所定回数だけ巻回することにより、インダクタなどの電子部品が得られる。 The resulting compact is then subjected to a heat treatment at, for example, 50 to 200°C, which hardens the resin and fixes the soft magnetic metal particles via the resin, resulting in a powder core 100 of a predetermined shape, for example, as shown in Figure 3A. An electronic component such as an inductor can be obtained by winding a wire around the resulting powder core a predetermined number of times.
　第４実施形態
（圧粉磁心）
図３Ｂに示すように、圧粉磁心１００は、第１の粒子１ａを含む軟磁性金属粉末と、第１の粒子１ａ以外のその他の粒子、たとえば第１の粒子１ａよりも平均粒径（Ｄ５０）が小さい第２の粒子１ｂを含むその他の磁性粉末との混合粉末から構成され、所定の形状に形成されていてもよい。 Fourth embodiment (powder core)
As shown in FIG. 3B , the powder core 100 may be composed of a mixed powder of a soft magnetic metal powder including first particles 1a and other particles other than the first particles 1a, such as other magnetic powder including second particles 1b having an average particle size (D50) smaller than that of the first particles 1a, and may be formed into a predetermined shape.
　この実施形態では、第１の粒子１ａは、圧粉磁心１００の断面において、粒度分布のピークが６μｍ以上１００μｍ以下の範囲内にあり、比較的に平均粒径（Ｄ５０）が大きな大径粒子であり、第２の粒子１ｂは、粒度分布のピークが２μｍ以上６μｍ未満かつ第１の粒子１aよりも小さい範囲内にあり、平均粒径（Ｄ５０）の比較的小さい中程度の中径
粒子である。大径粒子と中径粒子とは、第１実施形態と同様な組成の軟磁性金属粒子で構
成してあり、組成が同じでも異なっていてもよい。 In this embodiment, the first particles 1a are large-diameter particles having a relatively large average particle size (D50) with a particle size distribution peak in the range of 6 μm to 100 μm in the cross section of the powder core 100, and the second particles 1b are medium-diameter particles having a relatively small average particle size (D50) with a particle size distribution peak in the range of 2 μm to less than 6 μm, which is smaller than that of the first particles 1a. The large and medium-diameter particles are composed of soft magnetic metal particles having the same composition as in the first embodiment, and may have the same or different compositions.
　本実施形態では、第１の粒子１ａおよび第２の粒子１ｂの内の少なくとも一方が、第１実施形態または第２実施形態の被覆粒子１と同様な被覆部１０を有する。 In this embodiment, at least one of the first particle 1a and the second particle 1b has a coating portion 10 similar to the coated particle 1 of the first or second embodiment.
　あるいはまた、図３Ｃに示すように、圧粉磁心１００は、第１の粒子１ａを含む軟磁性金属粉末と、第１の粒子１ａ以外のその他の粒子、たとえば第１の粒子１ａよりも平均粒径（Ｄ５０）が小さい第２の粒子１ｂと、第２の粒子１ｂよりも平均粒径（Ｄ５０）が小さい第３の粒子１ｃとを含むその他の磁性粉末との混合粉末から構成され、所定の形状に形成されていてもよい。 Alternatively, as shown in FIG. 3C, the powder core 100 may be made of a mixed powder of soft magnetic metal powder containing first particles 1a and other magnetic powder containing particles other than the first particles 1a, such as second particles 1b having a smaller average particle size (D50) than the first particles 1a and third particles 1c having a smaller average particle size (D50) than the second particles 1b, and formed into a predetermined shape.
　第３の粒子１ｃは、たとえば粒度分布のピークが２μｍ以下の範囲内にあり、比較的に平均粒径（Ｄ５０）が小さい小径粒子である。本実施形態では、第１の粒子１ａ、第２の粒子１ｂおよび第３の粒子１ｃの内の少なくとも一つが、第１実施形態または第２実施形態の被覆粒子１と同様な被覆部１０を有する。大径粒子と中径粒子と小径粒子とは、第１実施形態と同様な組成の軟磁性金属粒子で構成してあり、組成が相互に同じでも異なっていてもよい。 The third particles 1c are small-diameter particles with a relatively small average particle size (D50), for example with a particle size distribution peak in the range of 2 μm or less. In this embodiment, at least one of the first particles 1a, the second particles 1b, and the third particles 1c has a coating portion 10 similar to that of the coated particles 1 of the first or second embodiment. The large, medium, and small particles are composed of soft magnetic metal particles with the same composition as in the first embodiment, and may have the same or different compositions.
　本実施形態の圧粉磁心１００は、第３実施形態の圧粉磁心と同様にして製造することができる。 The powder magnetic core 100 of this embodiment can be manufactured in the same manner as the powder magnetic core of the third embodiment.
　第５実施形態
（電子部品）
また、本実施形態に係る電子部品は、前述した被覆部を有する軟磁性金属粒子を含む電子部品であれば特に制限されない。たとえば、所定形状の圧粉磁心内部に、空芯コイルが埋設された磁性部品を有するインダクタなどの電子部品であってもよいし、所定形状の圧粉磁心の表面にワイヤが所定の巻き数だけ巻回されてなるトランスなどの電子部品であってもよい。 Fifth embodiment (electronic component)
The electronic component according to the present embodiment is not particularly limited as long as it is an electronic component containing soft magnetic metal particles having the above-mentioned coating portion. For example, it may be an electronic component such as an inductor having a magnetic component in which an air-core coil is embedded inside a powder magnetic core of a predetermined shape, or an electronic component such as a transformer in which a wire is wound a predetermined number of times around the surface of a powder magnetic core of a predetermined shape.
　さらに、本実施形態に係る電子部品は、たとえば電源回路に用いられるインダクタ、リアクトル、ＤＣ―ＤＣコンバータなどであってもよい。また、本実施形態に係る軟磁性金属粉末を有する電子部品としては、コア以外の電子部品、たとえば磁性シートなどであってもよい。 Furthermore, the electronic component according to this embodiment may be, for example, an inductor, a reactor, a DC-DC converter, etc., used in a power supply circuit. Furthermore, the electronic component having the soft magnetic metal powder according to this embodiment may be an electronic component other than a core, such as a magnetic sheet.
　以上、本発明の実施形態について説明してきたが、本発明は上記の実施形態に何ら限定されるものではなく、本発明の範囲内において種々の態様で改変しても良い。たとえば上述した実施形態の各構成要素を組み合わせた実施形態も考えられる。 Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and may be modified in various ways within the scope of the present invention. For example, embodiments that combine the components of the above-mentioned embodiments are also possible.
　以下、本発明の実施例および比較例について、実験例に基づき説明するが、本発明は、これら実施例に限定されない。 Below, examples and comparative examples of the present invention will be explained based on experimental examples, but the present invention is not limited to these examples.
　実験１
金属軟磁性材料として、原子数比でＳｉ／Ｆｅ＝２：９８のＦｅ－Ｓｉ系合金粒子を水アトマイズ法で作製した。このときの乾燥は窒素ガス雰囲気下で行った。当該Ｆｅ－Ｓｉ系合金粒子の粒子径のＤ５０は６μｍであった。 Experiment 1
As the metallic soft magnetic material, Fe-Si alloy particles with an atomic ratio of Si/Fe=2:98 were prepared by a water atomization method. Drying was performed under a nitrogen gas atmosphere. The particle diameter D50 of the Fe-Si alloy particles was 6 μm.
　Ｆｅ－Ｓｉ系合金粒子を酸素濃度５００ｐｐｍの雰囲気下８００°Ｃ０．２時間で第１の熱処理を行い、粒子の表面に第１の被覆部を形成した。 The Fe-Si alloy particles were subjected to a first heat treatment at 800°C for 0.2 hours in an atmosphere with an oxygen concentration of 500 ppm, forming a first coating portion on the surface of the particles.
　次に、第１の被覆部を形成したのち、ＴＥＯＳを用いたゾルゲル法により、Ｓｉを含む酸化物からなる第２の被覆部を粒子の表面に形成した。 Next, after forming the first coating, a second coating made of an oxide containing Si was formed on the surface of the particle by a sol-gel method using TEOS.
　続いて、第２の被覆部が形成された粉末を、酸素濃度１０ｐｐｍの雰囲気下にて、３００°Ｃで４時間の熱処理（第２の熱処理）を行った。このような第２の熱処理を行うことにより、軟磁性金属粒子を構成するＦｅおよびその他の金属元素が、第２の被覆部内を拡散して、第２の被覆部の表面において酸素と結合し、Ｆｅの酸化物を含む第３の被覆部を形成した。 The powder with the second coating formed thereon was then subjected to a heat treatment (second heat treatment) at 300°C for 4 hours in an atmosphere with an oxygen concentration of 10 ppm. By carrying out such a second heat treatment, the Fe and other metal elements constituting the soft magnetic metal particles diffused within the second coating and bonded with oxygen on the surface of the second coating, forming a third coating containing oxides of Fe.
　このようにして得られた被覆部を有する軟磁性金属粒子の試料１について、その表面近くの分析を、たとえば以下のようにして行ったが、その他の方法を用いてもよい。 Analysis of the surface of sample 1 of soft magnetic metal particles having a coating thus obtained was carried out, for example, as follows, but other methods may also be used.
　まず、軟磁性金属粒子の表面に、Ｐｔスパッタを行い厚みが３０ｎｍのＰｔ保護下地膜を形成した。その後、集束イオンビーム加工観察装置（ＦＩＢ：Focused Ion Beam）に金属粒子試料を入れ、その表面に電子線デポジションを行い、約１００ｎｍのＰｔ保護中間膜を形成し、さらにその表面にＧａイオンビームでＰｔデポジションを行い、厚み約２μｍのＰｔ保護表面膜を形成した。これらの表面保護膜を含む軟磁性金属粒子の表面からイオンビームによってマイクロサンプルを切り出し、その後薄膜化して厚み約５０ｎｍのサンプル薄膜を準備した。得られたサンプル薄膜を、ＴＥＭにより観察し、図２に示すような被覆部１０を含む粒子２の表面のＨＡＡＤＦ－ＳＴＥＭ像を得た。 First, Pt sputtering was performed on the surface of the soft magnetic metal particles to form a Pt protective undercoat film with a thickness of 30 nm. After that, the metal particle sample was placed in a focused ion beam processing and observation device (FIB: Focused Ion Beam) and electron beam deposition was performed on the surface to form a Pt protective intermediate film with a thickness of approximately 100 nm. Pt was then deposited on the surface with a Ga ion beam to form a Pt protective surface film with a thickness of approximately 2 μm. Microsamples were cut out from the surfaces of the soft magnetic metal particles including these surface protective films using an ion beam, and then thinned to prepare sample thin films with a thickness of approximately 50 nm. The obtained sample thin films were observed using a TEM, and a HAADF-STEM image of the surface of particle 2 including the coating portion 10 as shown in Figure 2 was obtained.
　被覆部１０には、粒子２から外側に、明暗のコントラストが異なる第１の被覆部１１、第２の被覆部１２および第３の被覆部１３が、この順で積層してあることが観察された。なお、層の厚みが０．８ｎｍ以下の層に関しては、被覆部としてはカウントしなかった。また、幅１００ｎｍの視野を２０視野以上確認し、粒子２の観察した視野の周囲長の半分以上の個所で３層構造が生成していることを確認した。 It was observed that the coating portion 10 had a first coating portion 11, a second coating portion 12, and a third coating portion 13, which have different light and dark contrasts, layered in this order from the particle 2 outward. Note that layers with a thickness of 0.8 nm or less were not counted as coating portions. In addition, more than 20 fields of view with a width of 100 nm were observed, and it was confirmed that a three-layer structure was formed in more than half of the perimeter of the observed fields of view of the particle 2.
　また、ＨＡＡＤＦ－ＳＴＥＭ像を観察した同じ箇所に関して、ＳＴＥＭ－ＥＤＸ分析もしくはＳＴＥＭ－ＥＥＬＳ分析によって、Ｆｅ濃度が各被覆部１１～１３で異なっていることを確認した。特に、ＦｅとＳｉとＯに関して、被覆部１１～１３での濃度分布を示した結果の一例を図４Ａに示す。図４Ａにおいて、横軸は、粒子２の中心部からの距離を示し、縦軸は、各元素の濃度を原子％で示したものを規格化している。 Furthermore, it was confirmed by STEM-EDX analysis or STEM-EELS analysis of the same locations where the HAADF-STEM images were observed that the Fe concentration differed in each of the coating parts 11 to 13. In particular, Figure 4A shows an example of the concentration distribution of Fe, Si, and O in the coating parts 11 to 13. In Figure 4A, the horizontal axis shows the distance from the center of the particle 2, and the vertical axis shows the normalized concentration of each element in atomic %.
　各被覆部１１～１３の各部について、たとえば図２中の点線に示す観察範囲（０．６ｎｍ×１００ｎｍ）でＥＤＸ分析を行い、Ｆｅ原子とＳｉ原子の存在割合の合計を１００原子％として、定量を行った。そして第１の被覆部１１におけるＦｅ原子の存在割合をＦｅ１、第２の被覆部１２におけるＦｅ原子の存在割合をＦｅ２、第３の被覆部１３におけるＦｅ原子の存在割合をＦｅ３とした。なお、Ｆｅ原子の存在割合は、１０視野について測定し、それらの平均として求めた。結果を表１に示す。 EDX analysis was performed on each of the coated portions 11 to 13 in the observation range (0.6 nm x 100 nm) shown by the dotted line in Figure 2, for example, and quantification was performed with the sum of the abundance ratios of Fe atoms and Si atoms set to 100 atomic %. The abundance ratio of Fe atoms in the first coated portion 11 was set to Fe1, the abundance ratio of Fe atoms in the second coated portion 12 to Fe2, and the abundance ratio of Fe atoms in the third coated portion 13 to Fe3. The abundance ratio of Fe atoms was measured in 10 fields of view and calculated as the average. The results are shown in Table 1.
　また、第１の被覆部の厚みｔ１、第２の被覆部の厚みｔ２および第３の被覆部の厚みｔ３は、図２に示すＨＡＡＤＦ－ＳＴＥＭ像を用いて、各被覆部１１～１３で明暗のコントラストが変化する境界相互間の距離の平均として求めた。平均の計算に際しては、各被覆部１１～１３の長手方向に沿って１００ｎｍの距離を一つの観察範囲とし、各観察範囲の長手方向に沿って２０ｎｍ毎に測定し、さらに、１０視野について同様に測定し、平均を求めた。また、各被覆部１１～１３の厚みｔ１～ｔ３の合計値を、被覆部１０の厚み合計Ｔとした。結果を表１に示す。 The thickness t1 of the first coating portion, the thickness t2 of the second coating portion, and the thickness t3 of the third coating portion were calculated as the average of the distances between the boundaries where the light-dark contrast changes in each of the coating portions 11-13, using the HAADF-STEM image shown in Figure 2. When calculating the average, a distance of 100 nm along the longitudinal direction of each of the coating portions 11-13 was set as one observation range, and measurements were made every 20 nm along the longitudinal direction of each observation range, and further measurements were made in the same manner for 10 visual fields to calculate the average. The sum of the thicknesses t1-t3 of each of the coating portions 11-13 was taken as the total thickness T of the coating portion 10. The results are shown in Table 1.
　粉末の抵抗率は、粉体抵抗測定装置を用いて、粉末に０．６ｔ／ｃｍ2の圧力を印加した状態での抵抗率を測定して求めた。結果を表１に示す。 The resistivity of the powder was determined by measuring the resistivity of the powder with a powder resistivity measuring device while applying a pressure of 0.6 t/cm 2 to the powder. The results are shown in Table 1.
　続いて、圧粉磁心の評価を行った。上記のようにして得られた軟磁性金属粉末１００ｗｔ％に対して樹脂量が３ｗｔ％となるように秤量し、アセトンに加えて溶液化し、その溶液と軟磁性金属粉末とを混合した。混合後、アセトンを揮発させて得られた顆粒を、３５５μｍのメッシュで整粒した。これを外径１１ｍｍ、内径６．５ｍｍのトロイダル形状の金型に充填し、透磁率が約２０になるように成形圧を調整し、圧粉磁心を得た。得られた圧粉磁心の成形体を１８０°Ｃで１時間熱処理し、樹脂を硬化させて圧粉磁心（磁気コア）のサンプルを得た。 Next, the powder magnetic core was evaluated. The resin was weighed out so that the amount was 3 wt% relative to 100 wt% of the soft magnetic metal powder obtained as described above, and added to acetone to form a solution, and the solution was mixed with the soft magnetic metal powder. After mixing, the acetone was evaporated to obtain granules, which were then sized using a 355 μm mesh. This was filled into a toroidal mold with an outer diameter of 11 mm and an inner diameter of 6.5 mm, and the molding pressure was adjusted so that the magnetic permeability was approximately 20, obtaining a powder magnetic core. The obtained molded body of the powder magnetic core was heat-treated at 180°C for 1 hour to harden the resin and obtain a sample of the powder magnetic core (magnetic core).
　作製した圧粉磁心のサンプルに対して、透磁率（μ０）および透磁率（μ８ｋ）を測定した。まず、トロイダル形状の磁気コアに対して、ワイヤを巻回した。そして、ＬＣＲメータおよび直流バイアス電源を用いて、周波数１ＭＨｚにおける磁気コアのインダクタンスを測定した。 The magnetic permeability (μ0) and magnetic permeability (μ8k) of the powder core samples were measured. First, wire was wound around a toroidal magnetic core. Then, the inductance of the magnetic core at a frequency of 1 MHz was measured using an LCR meter and a DC bias power supply.
　より具体的には、直流磁界を印加していない条件（０ｋＡ／ｍ）でのインダクタンスと、８ｋＡ／ｍの直流磁界を印加した条件でのインダクタンスと、を測定し、これらインダクタンスからμ０（０Ａ／ｍでの透磁率）およびμ８Ｋ（８ｋＡ／ｍでの透磁率）を算出した。直流重畳特性は、直流磁界を印加した際の透磁率の変化率に基づいて評価した。つまり、透磁率の変化率（単位％）は、（μ０－μ８Ｋ）／μ０で表され、この透磁率の変化率が小さいほど、直流重畳特性が良好であると判断できる。結果を表１に示す。 More specifically, the inductance was measured when no DC magnetic field was applied (0 kA/m) and when a DC magnetic field of 8 kA/m was applied, and μ0 (magnetic permeability at 0 A/m) and μ8K (magnetic permeability at 8 kA/m) were calculated from these inductances. The DC superposition characteristics were evaluated based on the rate of change in magnetic permeability when a DC magnetic field was applied. In other words, the rate of change in magnetic permeability (unit: %) is expressed as (μ0-μ8K)/μ0, and it can be determined that the smaller this rate of change in magnetic permeability is, the better the DC superposition characteristics are. The results are shown in Table 1.
　試料２では、第１の熱処理の酸素濃度を１０ｐｐｍとしたことと、第２の熱処理を行わなかったこと以外は試料１と同様にして、試料２に係る軟磁性粉末と圧粉磁心を作製し、試料１と同様な測定を行った。結果を表１に示す。試料２では、第１の被覆部も第３の被覆部も形成されていなかった。 For sample 2, the soft magnetic powder and dust core for sample 2 were prepared in the same manner as for sample 1, except that the oxygen concentration in the first heat treatment was set to 10 ppm and the second heat treatment was not performed, and measurements were performed similarly to those for sample 1. The results are shown in Table 1. For sample 2, neither the first coating portion nor the third coating portion was formed.
　試料３では、第２の被覆部の形成後に第２の熱処理を行わなかった以外は、試料１と同様にして、試料３に係る軟磁性金属粉末と圧粉磁心を作製し、試料１と同様な測定を行った。結果を表１に示す。試料３では、第３の被覆部が形成されなかった。 For sample 3, the soft magnetic metal powder and powder magnetic core for sample 3 were prepared in the same manner as for sample 1, except that the second heat treatment was not performed after the formation of the second coating portion, and measurements were performed in the same manner as for sample 1. The results are shown in Table 1. For sample 3, the third coating portion was not formed.
　試料４では、第１の熱処理時の酸素濃度を１０ｐｐｍとした以外は、試料１と同様にして、試料４に係る軟磁性金属粉末と圧粉磁心を作製し、試料１と同様な測定を行った。結果を表１に示す。試料４では、第１の被覆部が形成されていない状態で、第２の被覆部および第３の被覆部が形成された。 For sample 4, the soft magnetic metal powder and powder magnetic core for sample 4 were prepared in the same manner as for sample 1, except that the oxygen concentration during the first heat treatment was set to 10 ppm, and measurements were performed similarly to those for sample 1. The results are shown in Table 1. For sample 4, the second coating portion and the third coating portion were formed without the first coating portion being formed.
　表１に示すように、実施例である試料１の軟磁性金属粉末は、比較例である試料２および３および４の軟磁性金属粉末と比較して、高い粉体抵抗を有することが判明した。そして、実施例の軟磁性金属粉末を使用して作製した圧粉磁心は、比較例に対して優れた直流重畳特性を有していることが判明した。 As shown in Table 1, it was found that the soft magnetic metal powder of sample 1, which is an embodiment of the present invention, has a higher powder resistance than the soft magnetic metal powders of samples 2, 3, and 4, which are comparative examples. It was also found that the dust cores made using the soft magnetic metal powder of the embodiment of the present invention have superior DC bias characteristics compared to the comparative examples.
　実験２－１
試料５～１２では、第２の被覆部を形成したのちの第２の熱処理の温度を、表２に記載した温度に変更した以外は、試料１と同様にして、軟磁性金属粉末および圧粉磁心を作製して、試料１と同様の評価を行った。結果を表２－１に示す。表２－１に示すように、第１の被覆部のＦｅ濃度（Ｆｅ１）、第２の被覆部のＦｅ濃度（Ｆｅ２）および第３の被覆部のＦｅ濃度（Ｆｅ３）を調整することができることが判明した。 Experiment 2-1
For Samples 5 to 12, soft magnetic metal powders and dust cores were prepared in the same manner as Sample 1, except that the temperature of the second heat treatment after forming the second covering portion was changed to the temperatures shown in Table 2, and evaluations were performed in the same manner as Sample 1. The results are shown in Table 2-1. As shown in Table 2-1, it was found that the Fe concentration of the first covering portion (Fe1), the Fe concentration of the second covering portion (Fe2), and the Fe concentration of the third covering portion (Fe3) could be adjusted.
　また、表２－１に示すように、試料５～１２の各実施例の軟磁性金属粉末は、いずれも１．０×１０5Ω・ｃｍ以上の高い粉体抵抗を有しており、さらに実施例の軟磁性金属粉末を使用して作製した圧粉磁心は、直流重畳特性にも優れていることが判明した。 Furthermore, as shown in Table 2-1, the soft magnetic metal powders of each embodiment, samples 5 to 12, all have a high powder resistivity of 1.0 x 105 Ω·cm or more, and it was found that the dust cores made using the soft magnetic metal powders of the embodiments also have excellent DC bias characteristics.
　実験２－２
　試料１３～１８では、第２の熱処理時の酸素濃度を表２－２に記載の濃度へと変更したこと以外は、試料１と同様にして、軟磁性金属粉末および圧粉磁心を作製し、試料１と同様な評価を行った。結果を表２－２に示す。表２－２に示すように、第２の熱処理時の酸素濃度を変化させることで第２の被覆部のＦｅ濃度を調整できることが確認できた。 Experiment 2-2
For Samples 13 to 18, soft magnetic metal powders and powder magnetic cores were produced in the same manner as Sample 1, except that the oxygen concentration during the second heat treatment was changed to the concentrations shown in Table 2-2, and evaluations were performed in the same manner as Sample 1. The results are shown in Table 2-2. As shown in Table 2-2, it was confirmed that the Fe concentration of the second coating portion could be adjusted by changing the oxygen concentration during the second heat treatment.
　また、表２－２に示すように、試料１３～１８の各実施例の軟磁性金属粉末は、第２の被覆部のＦｅ濃度が第２の被覆部のＳｉ濃度よりも低い場合だけでなく、高い場合であっても、Ｆｅ１、Ｆｅ２、Ｆｅ３が所定の関係を満足することにより、いずれも１．０×１０5Ω・ｃｍ以上の高い粉体抵抗を有しており、さらに実施例の軟磁性金属粉末を使用して作製した圧粉磁心は、直流重畳特性にも優れていることが判明した。 Furthermore, as shown in Table 2-2, the soft magnetic metal powders of each embodiment of samples 13 to 18 have high powder resistivity of 1.0 x 105 Ω-cm or more, not only when the Fe concentration of the second coating portion is lower than the Si concentration of the second coating portion, but also when it is higher, because Fe1 , Fe2, and Fe3 satisfy a specified relationship, and it was further found that the powder cores made using the soft magnetic metal powders of the embodiments also have excellent DC superposition characteristics.
　実験３
試料１９～２４では、Ｓｉの濃度が表３－１に記載の数値となる軟磁性金属粉末を用いたこと以外は試料２と同様にして、軟磁性金属粉末および圧粉磁心を作製して、試料１と同様な評価を行った。試料２５～３０では、Ｓｉの濃度が表３－１に記載の数値となる軟磁性金属粉末を用いたこと以外は試料３と同様にして、軟磁性金属粉末および圧粉磁心を作製して、試料１と同様な評価を行った。試料３１～６０では、Ｓｉの濃度が表３－１および表３－２に記載の数値となる軟磁性金属粉末を用いたことと、第２熱処理の温度を表３－１および表３－２に記載の温度に変えたこと以外は試料１と同様にして、軟磁性金属粉末および圧粉磁心を作製して、試料１と同様な評価を行った。結果を表３―１および表３―２に示す。 Experiment 3
For samples 19 to 24, soft magnetic metal powders and powder magnetic cores were prepared in the same manner as sample 2, except that soft magnetic metal powders having a Si concentration as shown in Table 3-1 were used, and evaluations were performed in the same manner as sample 1. For samples 25 to 30, soft magnetic metal powders and powder magnetic cores were prepared in the same manner as sample 3, except that soft magnetic metal powders having a Si concentration as shown in Table 3-1 were used, and evaluations were performed in the same manner as sample 1. For samples 31 to 60, soft magnetic metal powders and powder magnetic cores were prepared in the same manner as sample 1, except that soft magnetic metal powders having a Si concentration as shown in Tables 3-1 and 3-2 were used, and the temperature of the second heat treatment was changed to the temperature shown in Tables 3-1 and 3-2, and evaluations were performed in the same manner as sample 1. The results are shown in Tables 3-1 and 3-2.
　表３―１および表３―２に示すように、試料３１～６０の各実施例の軟磁性金属粉末は、試料１９～２４および試料２５～３０の比較例に比較して、高い粉体抵抗を有しており、また、直流重畳特性に優れた圧粉磁心が得られることが判明した。 As shown in Tables 3-1 and 3-2, the soft magnetic metal powders of the examples, Samples 31 to 60, have higher powder resistivity than the comparative examples, Samples 19 to 24 and Samples 25 to 30, and it was found that a dust core with excellent DC bias characteristics was obtained.
　実験４
試料６１～６５では、第１の熱処理時の酸素濃度を表４に記載の濃度へと変更したこと以外は、試料１と同様にして、軟磁性金属粉末および圧粉磁心を作製し、試料１と同様な評価を行った。結果を表４に示す。表４に示すように、第１の熱処理時の酸素濃度を変化させることで第１の被覆部の厚みｔ１を調整することができることが確認できた。 Experiment 4
For Samples 61 to 65, soft magnetic metal powders and powder magnetic cores were produced in the same manner as Sample 1, except that the oxygen concentration during the first heat treatment was changed to the concentrations shown in Table 4, and evaluations were performed in the same manner as Sample 1. The results are shown in Table 4. As shown in Table 4, it was confirmed that the thickness t1 of the first covering portion could be adjusted by changing the oxygen concentration during the first heat treatment.
　表４に示すように、第１の被覆部の厚みｔ１が変化しても、Ｆｅ１、Ｆｅ２、Ｆｅ３が所定の関係を満足することにより、実施例である軟磁性金属粉末（試料６１～６５）は、高い粉体抵抗を有することが判明した。また、実施例の軟磁性金属粉末を使用して作製した圧粉磁心は、優れた直流重畳特性を有していることが判明した。 As shown in Table 4, even if the thickness t1 of the first coating portion changes, Fe1, Fe2, and Fe3 satisfy a predetermined relationship, and it was found that the soft magnetic metal powders of the examples (samples 61 to 65) have high powder resistance. In addition, it was found that the dust cores made using the soft magnetic metal powders of the examples have excellent DC superposition characteristics.
　実験５―１
試料６６～８９では、第１の熱処理時の酸素濃度を表５に記載の値に変更したことと、金属材料１００ｇあたりのＴＥＯＳの添加量（ｇ）及び第２の熱処理の時間を表５に記載の値に変更した以外の条件は、試料１と同様にして、軟磁性金属粉末および圧粉磁心を作製し、試料１と同様な評価を行った。結果を表５―１に示す。表５―１に示すように、それぞれの被覆部の厚みｔ１～ｔ３を調整することができることが確認できた。 Experiment 5-1
For Samples 66 to 89, soft magnetic metal powders and dust cores were produced under the same conditions as Sample 1, except that the oxygen concentration during the first heat treatment was changed to the value shown in Table 5, and the amount of TEOS added (g) per 100 g of metal material and the time of the second heat treatment were changed to the values shown in Table 5. The results are shown in Table 5-1. As shown in Table 5-1, it was confirmed that the thicknesses t1 to t3 of the respective coating portions could be adjusted.
　表５―１に示すように、それぞれの被覆部の厚みを変量した場合においても、Ｆｅ１、Ｆｅ２、Ｆｅ３が所定の関係を満足することにより、実施例である軟磁性金属粉末（試料６６～８９）は、高い粉体抵抗を与えることが判明した。そして、実施例の軟磁性金属粉末を使用して作製した圧粉磁心は、優れた直流重畳特性を有していることが判明した。 As shown in Table 5-1, even when the thickness of each coating was varied, Fe1, Fe2, and Fe3 satisfied the specified relationship, and it was found that the soft magnetic metal powders of the examples (samples 66-89) provided high powder resistance. It was also found that the dust cores made using the soft magnetic metal powders of the examples had excellent DC bias characteristics.
　実験５―２
試料９０～９７では、軟磁性粒子のＳｉ濃度を１５原子％としたことと、金属材料１００ｇあたりのＴＥＯＳの添加量（ｇ）及び第２の熱処理の時間を表５に記載の値に変更した以外の条件は、試料１と同様にして、軟磁性金属粉末および圧粉磁心を作製し、試料１と同様な評価を行った。結果を表５―２に示す。表５―２に示すように、それぞれの被覆部の厚みｔ１～ｔ３を調整することができることが確認できた。 Experiment 5-2
In samples 90 to 97, the Si concentration of the soft magnetic particles was set to 15 atomic %, and the amount of TEOS added (g) per 100 g of metal material and the time of the second heat treatment were changed to the values shown in Table 5. Except for this, soft magnetic metal powders and powder magnetic cores were produced under the same conditions as sample 1, and evaluations were performed in the same manner as sample 1. The results are shown in Table 5-2. As shown in Table 5-2, it was confirmed that the thicknesses t1 to t3 of the respective coating portions could be adjusted.
　表５―２に示すように、軟磁性粒子のＳｉ濃度を１５原子％とした系においても、それぞれの被覆部の厚みを変量した場合において、Ｆｅ１、Ｆｅ２、Ｆｅ３が所定の関係を満足することにより、実施例である軟磁性金属粉末（試料９０～９７）は、高い粉体抵抗を与えることが判明した。そして、実施例の軟磁性金属粉末を使用して作製した圧粉磁心は、優れた直流重畳特性を有していることが判明した。 As shown in Table 5-2, even in a system where the Si concentration of the soft magnetic particles is 15 atomic %, when the thickness of each coating is varied, Fe1, Fe2, and Fe3 satisfy a specified relationship, and it was found that the soft magnetic metal powders of the examples (samples 90-97) provide high powder resistance. It was also found that the dust cores made using the soft magnetic metal powders of the examples have excellent DC bias characteristics.
　実験６
試料９８～１０６では、軟磁性金属粉末の平均粒子径Ｄ５０を、表６に記載の値となるように調整したことと、ＴＥＯＳコート厚みが約２０ｎｍになるよう、ＢＥＴ比表面積から必要なＴＥＯＳ添加量を計算してＴＥＯＳ添加量を変更した以外は、試料３と同様に、軟磁性金属粉末および圧粉磁心を作製し、試料１と同様な評価を行った。結果を表６に示す。 Experiment 6
For samples 98 to 106, soft magnetic metal powders and dust cores were prepared in the same manner as sample 3, and evaluations were performed in the same manner as sample 1, except that the average particle diameter D50 of the soft magnetic metal powder was adjusted to the value shown in Table 6, and the amount of TEOS added was changed by calculating the amount of TEOS required from the BET specific surface area so that the TEOS coat thickness would be about 20 nm. The results are shown in Table 6.
　試料１０７～１１０では、軟磁性金属粉末の平均粒子径Ｄ５０を、表６に記載の値となるように調整したことと、ＴＥＯＳコート厚みが約１００ｎｍになるよう、ＢＥＴ比表面積から必要なＴＥＯＳ添加量を計算してＴＥＯＳ添加量を変更した以外は、試料３と同様に、軟磁性金属粉末および圧粉磁心を作製し、試料１と同様な評価を行った。結果を表６に示す。 For samples 107 to 110, the average particle diameter D50 of the soft magnetic metal powder was adjusted to the value shown in Table 6, and the amount of TEOS added was changed by calculating the amount of TEOS required from the BET specific surface area so that the TEOS coating thickness would be approximately 100 nm. Except for this, soft magnetic metal powders and dust cores were produced in the same manner as sample 3, and evaluated in the same manner as sample 1. The results are shown in Table 6.
試料１１１～１１９では、軟磁性金属粉末の平均粒子径Ｄ５０を、表６に記載の値となるように調整したことと、ＴＥＯＳコート厚みが約２０ｎｍになるよう、ＢＥＴ比表面積から必要なＴＥＯＳ添加量を計算してＴＥＯＳ添加量を変更した以外は、試料１と同様に、軟磁性金属粉末および圧粉磁心を作製し、試料１と同様な評価を行った。結果を表６に示す。 For samples 111 to 119, the average particle diameter D50 of the soft magnetic metal powder was adjusted to the value shown in Table 6, and the amount of TEOS added was changed by calculating the amount of TEOS required from the BET specific surface area so that the TEOS coating thickness would be approximately 20 nm. Except for this, soft magnetic metal powders and dust cores were produced in the same manner as sample 1, and evaluations were performed in the same manner as sample 1. The results are shown in Table 6.
　試料１２０～１２３では、軟磁性金属粉末の平均粒子径Ｄ５０を、表６に記載の値となるように調整したことと、ＴＥＯＳコート厚みが約１００ｎｍになるよう、ＢＥＴ比表面積から必要なＴＥＯＳ添加量を計算してＴＥＯＳ添加量を変更した以外は、試料１と同様に、軟磁性金属粉末および圧粉磁心を作製し、試料１と同様な評価を行った。結果を表６に示す。 For samples 120 to 123, the average particle diameter D50 of the soft magnetic metal powder was adjusted to the value shown in Table 6, and the amount of TEOS added was changed by calculating the amount of TEOS required from the BET specific surface area so that the TEOS coating thickness would be approximately 100 nm. Except for this, soft magnetic metal powders and dust cores were produced in the same manner as sample 1, and evaluations were performed in the same manner as sample 1. The results are shown in Table 6.
　表６に示されるように、Ｆｅ－Ｓｉ系合金粒子の粒子径を変量した場合にも、Ｆｅ１、Ｆｅ２、Ｆｅ３が所定の関係を満足することにより、実施例である軟磁性金属粉末（試料１１１～１２３）を使用して作製した圧粉磁心は、比較例（試料９８～１１０）とくらべて、優れた直流重畳特性を有していることが判明した。 As shown in Table 6, even when the particle size of the Fe-Si alloy particles is varied, Fe1, Fe2, and Fe3 satisfy the specified relationship, and it has been found that the powder magnetic cores made using the soft magnetic metal powders of the examples (samples 111-123) have superior DC bias characteristics compared to the comparative examples (samples 98-110).
　実験７
試料１２４～１４３では、軟磁性金属粒子の組成を、表７に記載の組成の粒子へと変更した。それ以外は試料１２４～１３３では試料３と同様に、試料１３４～１４３では試料1と同様に、軟磁性金属粉末および圧粉磁心を作製し、試料１と同様な評価を行った。結
果を表７に示す。 Experiment 7
In samples 124 to 143, the composition of the soft magnetic metal particles was changed to particles having the composition shown in Table 7. Otherwise, soft magnetic metal powders and dust cores were prepared in the same manner as sample 3 for samples 124 to 133, and in the same manner as sample 1 for samples 134 to 143, and were evaluated in the same manner as sample 1. The results are shown in Table 7.
　表７に示すように、軟磁性合金粒子の組成を変更した場合にも、Ｆｅ１、Ｆｅ２、Ｆｅ３が所定の関係を満足することにより、実施例である軟磁性金属粉末（試料１３４～１４３）を使用して作製した圧粉磁心は、比較例（試料１２４～１３３）とくらべて、優れた直流重畳特性を有していることが判明した。 As shown in Table 7, even when the composition of the soft magnetic alloy particles was changed, Fe1, Fe2, and Fe3 satisfied the specified relationship, and it was found that the powder magnetic cores made using the soft magnetic metal powders of the examples (samples 134-143) had superior DC bias characteristics compared to the comparative examples (samples 124-133).
　実験８
試料１４４～１５１では、軟磁性金属粒子として、表８に記載のナノ結晶粒子を用意し、それらの表面に被覆部を形成した。また、第１の熱処理温度は４００℃とした。その他の点は試料１４４～１４７では試料３と同様に、試料１４８～１５１では試料１と同様に、軟磁性金属粉末および圧粉磁心を得て、試料１と同様の評価を行った。結果を表８に示す。 Experiment 8
For samples 144 to 151, nanocrystalline particles as shown in Table 8 were prepared as the soft magnetic metal particles, and coating portions were formed on the surfaces of these particles. The first heat treatment temperature was 400° C. In other respects, soft magnetic metal powders and dust cores were obtained in the same manner as sample 3 for samples 144 to 147, and in the same manner as sample 1 for samples 148 to 151, and evaluations were performed in the same manner as for sample 1. The results are shown in Table 8.
試料１５２～１７１では、軟磁性金属粒子として、表９に記載の非晶質粒子を用意し、それらの表面に被覆部を形成した。また、第１の熱処理温度を３００℃とした。その他の点は試料１５２～１６１では試料３と同様に、試料１６２～１７１では試料１と同様に、軟磁性金属粉末および圧粉磁心を得て、試料１と同様の評価を行った。結果を表９に示す。 For samples 152 to 171, the amorphous particles shown in Table 9 were prepared as soft magnetic metal particles, and coatings were formed on their surfaces. The first heat treatment temperature was set to 300°C. In other respects, soft magnetic metal powder and dust cores were obtained in the same manner as sample 3 for samples 152 to 161, and in the same manner as sample 1 for samples 162 to 171, and evaluations were performed in the same manner as for sample 1. The results are shown in Table 9.
　表８および表９に示すように、軟磁性合金粒子の組成および構造を変更した場合にも、Ｆｅ１、Ｆｅ２、Ｆｅ３が所定の関係を満足することにより、実施例である軟磁性金属粉末を使用して作製した圧粉磁心（試料１４８～１５１および１６２～１７１）は、比較例（試料１４４～１４７および１５２～１６１）とくらべて、優れた直流重畳特性を有していることが判明した。 As shown in Tables 8 and 9, even when the composition and structure of the soft magnetic alloy particles were changed, Fe1, Fe2, and Fe3 satisfied the specified relationship, and it was found that the powder cores made using the soft magnetic metal powders of the examples (samples 148-151 and 162-171) had superior DC bias characteristics compared to the comparative examples (samples 144-147 and 152-161).
　実験９
試料１７２では、軟磁性金属粒子を水アトマイズ法にて作製する際に、粒子の乾燥を真空条件下で行うとともに、第１の熱処理時の酸素濃度を３００ｐｐｍとした以外は試料１と同様の操作を行い、軟磁性金属粉末および圧粉磁心を作製し、試料１と同様の評価を行った。結果を表１０－１に示す。第１の被覆部よりもさらに内側に、内側被覆部を形成することができることが確認できた。 Experiment 9
For sample 172, the same operations as those of sample 1 were carried out except that when the soft magnetic metal particles were produced by the water atomization method, the particles were dried under vacuum conditions and the oxygen concentration during the first heat treatment was set to 300 ppm, to produce a soft magnetic metal powder and a powder magnetic core, which were then evaluated in the same manner as sample 1. The results are shown in Table 10-1. It was confirmed that an inner coating portion could be formed further inside than the first coating portion.
　表１０－１に示すように、第１の被覆部よりも内部にＦｅ濃度がＦｅ１より低い内側被覆部が形成されている場合であっても、Ｆｅ１、Ｆｅ２、Ｆｅ３が所定の関係を満足することにより、実施例である軟磁性金属粉末（試料１７２）は、高い粉体抵抗を与えることが判明した。そして、実施例の軟磁性金属粉末を使用して作製した圧粉磁心は、優れた直流重畳特性を有していることが判明した。 As shown in Table 10-1, even if an inner coating portion with a lower Fe concentration than Fe1 is formed inside the first coating portion, Fe1, Fe2, and Fe3 satisfy a predetermined relationship, and it was found that the soft magnetic metal powder of the embodiment (sample 172) provides high powder resistance. It was also found that the dust core made using the soft magnetic metal powder of the embodiment has excellent DC superposition characteristics.
　なお、試料１７２に係る被覆粒子について、試料１と同様にして、Ｆｅ、ＳｉおよびＯの濃度プロファイルを取得した結果、図４Ｂに示すような濃度分布を有しており、第１の被覆部のさらに内側に、第１の被覆部とは組成の異なる内側被覆部が形成されていることが確認できた。 Furthermore, the concentration profiles of Fe, Si, and O were obtained for the coated particles of sample 172 in the same manner as for sample 1. The results showed that the coated particles had the concentration distribution shown in Figure 4B, and it was confirmed that an inner coating layer with a different composition from the first coating layer was formed further inside the first coating layer.
　実験１０
試料１７３～１８４では、第３の被覆部を形成した後にさらに絶縁コーティングを行い、第３の被覆部の外側に、表１０－２に記載の厚み（ｔ５）および組成を有する外側被覆部を形成したこと以外は、試料１と同様にして軟磁性金属粉末および圧粉磁心を作製し、試料１と同様な評価を行った。結果を表１０－２に示す。 Experiment 10
For Samples 173 to 184, soft magnetic metal powders and dust cores were prepared in the same manner as Sample 1, except that after the formation of the third covering portion, an insulating coating was further performed, and an outer covering portion having the thickness (t5) and composition shown in Table 10-2 was formed on the outside of the third covering portion, and evaluations were performed in the same manner as Sample 1. The results are shown in Table 10-2.
　表１０－２に示すように、第３の被覆部の外側に外側被覆部が形成されている場合であっても、Ｆｅ１、Ｆｅ２、Ｆｅ３が所定の関係を満足することにより、実施例である軟磁性金属粉末（試料１７３～１８４）は、高い粉体抵抗を有することが判明した。そして、
絶縁コーティングを行って外側被覆部を形成した各実施例は、外側被覆部を形成していない実施例と比較して、さらに良好な粉体抵抗を有していることが判明した。また、外側被覆部をさらに形成した軟磁性金属粉末を使用して作製した圧粉磁心は、外側被覆部を形成していない例とくらべて、さらに優れた直流重畳特性を有していることが判明した。 As shown in Table 10-2, even when an outer coating portion is formed on the outside of the third coating portion, it was found that the soft magnetic metal powders of the examples (samples 173 to 184) have high powder resistivity because Fe1, Fe2, and Fe3 satisfy a predetermined relationship.
It was found that each of the examples in which an outer coating was formed by performing an insulating coating had better powder resistance than the examples in which an outer coating was not formed. Also, it was found that the dust core produced using the soft magnetic metal powder further having an outer coating had better DC bias characteristics than the examples in which an outer coating was not formed.
　実験１１
試料１８５、１８７、１８９、１９１では、圧粉磁心を作製する際に、試料３で得られた軟磁性金属粉末（平均粒径６μｍの被覆粒子）に加えて、表１１に記載の組成および平均粒子径（Ｄ５０）を有するその他の粒子を、平均粒子径の大きい順に質量比で８０：２０の存在割合となるように混合した粉末を使用した以外は、試料１と同様にして、圧粉磁心を作製した。試料１８６、１８８、１９０、１９２では、圧粉磁心を作製する際に、被覆粒子として、試料１で得られた軟磁性金属粉末（平均粒径６μｍの被覆粒子）に加えて、表１１に記載の組成および平均粒子径（Ｄ５０）を有するその他の粒子を、平均粒子径の大きい順に質量比で８０：２０の存在割合となるように混合した粉末を使用した以外は、試料１と同様にして、圧粉磁心を作製した。得られた圧粉磁心について、試料１と同様にして直流重畳特性を評価した。結果を表１１に示す。 Experiment 11
In samples 185, 187, 189, and 191, in addition to the soft magnetic metal powder (coated particles with an average particle size of 6 μm) obtained in sample 3, other particles having the composition and average particle size (D50) described in Table 11 were used in a mass ratio of 80:20 in descending order of average particle size. In samples 186, 188, 190, and 192, in addition to the soft magnetic metal powder (coated particles with an average particle size of 6 μm) obtained in sample 1, other particles having the composition and average particle size (D50) described in Table 11 were used in a mass ratio of 80:20 in descending order of average particle size. In the same manner as in sample 1, except that a powder was used in which a powder was mixed ...
　表１１に示すように、Ｆｅ１、Ｆｅ２、Ｆｅ３が所定の関係を満足する軟磁性金属粉末を含む２種類の金属粉末を混合して圧粉磁心（試料１８６，１８８，１９０，１９２）を作製した場合であっても、実験１と同様に、第３の被覆部が形成されていない各比較例（試料１８５，１８７，１８９，１９１）と比較して、優れた直流重畳特性を与えることが判明した。 As shown in Table 11, even when dust cores (samples 186, 188, 190, and 192) were made by mixing two types of metal powder, including soft magnetic metal powder in which Fe1, Fe2, and Fe3 satisfy a specified relationship, it was found that, as in Experiment 1, they provided superior DC bias characteristics compared to the comparative examples (samples 185, 187, 189, and 191) in which the third coating portion was not formed.
　実験１２
試料１９３では、圧粉磁心を作製する際に、試料３で得られた軟磁性金属粉末（平均粒径６μｍの被覆粒子）に加えて、その他の粒子として、平均粒径が約２０μｍであるＦｅ－Ｃｏ－Ｂ－Ｐ－Ｓｉ－Ｃｒ系の非晶質粒子と、さらにその他の粒子として、平均粒径が１μｍ以下であるＦｅ粒子を、平均粒子径の大きい順に質量比で８０：１０：１０の存在割合となるように混合した粉末を使用した以外は、試料１と同様にして、圧粉磁心を作製した。試料１９４では、圧粉磁心を作製する際に、被覆粒子として、試料１で得られた軟磁性金属粉末（平均粒径６μｍの被覆粒子）を使用した以外は試料１９３と同様にして、圧粉磁心を作製した。得られた圧粉磁心について、試料１と同様にして直流重畳特性を評価した。結果を表１２に示す。 Experiment 12
In sample 193, in addition to the soft magnetic metal powder (coated particles with an average particle size of 6 μm) obtained in sample 3, other particles were mixed with Fe-Co-B-P-Si-Cr amorphous particles with an average particle size of about 20 μm and Fe particles with an average particle size of 1 μm or less as other particles in a mass ratio of 80:10:10 in descending order of average particle size. A powder core was produced in the same manner as sample 193, except that a powder was used when the soft magnetic metal powder (coated particles with an average particle size of 6 μm) obtained in sample 1 was used as the coated particles. The obtained powder core was evaluated for DC superposition characteristics in the same manner as sample 1. The results are shown in Table 12.
　表１２に示すように、Ｆｅ１、Ｆｅ２、Ｆｅ３が所定の関係を満足する被覆粒子を含む３種類の粒子を混合して圧粉磁心（試料１９４）を作製した場合であっても、実験１と同様に、比較例（試料１９３）と比較して、優れた直流重畳特性を与えることが判明した。 As shown in Table 12, even when a powder magnetic core (sample 194) was produced by mixing three types of particles, including coated particles in which Fe1, Fe2, and Fe3 satisfy a specified relationship, it was found to have superior DC bias characteristics compared to the comparative example (sample 193), just as in Experiment 1.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000008
Figure JPOXMLDOC01-appb-T000008
Figure JPOXMLDOC01-appb-T000009
Figure JPOXMLDOC01-appb-T000009
Figure JPOXMLDOC01-appb-T000010
Figure JPOXMLDOC01-appb-T000010
Figure JPOXMLDOC01-appb-T000011
Figure JPOXMLDOC01-appb-T000011
Figure JPOXMLDOC01-appb-T000012
Figure JPOXMLDOC01-appb-T000012
Figure JPOXMLDOC01-appb-T000013
Figure JPOXMLDOC01-appb-T000013
Figure JPOXMLDOC01-appb-T000014
Figure JPOXMLDOC01-appb-T000014
Figure JPOXMLDOC01-appb-T000015
Figure JPOXMLDOC01-appb-T000015
Figure JPOXMLDOC01-appb-T000016
Figure JPOXMLDOC01-appb-T000016
　総合評価
　表１～表５に示すように、好ましくは、１．１≦Ｆｅ１／Ｆｅ２≦３４．０、さらに好ましくは１．２≦Ｆｅ１／Ｆｅ２≦３２．０、さらに好ましくは１．７≦Ｆｅ１／Ｆｅ２≦２０．０の関係を満足する場合に、軟磁性粉末の粉体抵抗がさらに向上することが確認できた。 As shown in the overall evaluation tables 1 to 5, it was confirmed that the powder resistance of the soft magnetic powder is further improved when the relationship of 1.1≦Fe1/Fe2≦34.0, more preferably 1.2≦Fe1/Fe2≦32.0, and even more preferably 1.7≦Fe1/Fe2≦20.0 is satisfied.
　また、表１～表５に示すように、好ましくは、２．０≦Ｆｅ２≦６５．０、さらに好ましくは４．０≦Ｆｅ２≦５０．０、さらに好ましくは５．０≦Ｆｅ２≦３０．０、さらに好ましくは９．０≦Ｆｅ２≦１８．０の範囲にあるときに、軟磁性粉末の粉体抵抗がさらに向上することが確認できた。 Furthermore, as shown in Tables 1 to 5, it was confirmed that the powder resistance of the soft magnetic powder is further improved when the range is preferably 2.0≦Fe2≦65.0, more preferably 4.0≦Fe2≦50.0, even more preferably 5.0≦Fe2≦30.0, and even more preferably 9.0≦Fe2≦18.0.
　さらに表１～表５に示すように、好ましくは、１．１≦Ｆｅ３／Ｆｅ２≦４１．０、さらに好ましくは１．２≦Ｆｅ３／Ｆｅ２≦３５．０、さらに好ましくは１．３≦Ｆｅ３／Ｆｅ２≦２０．０の範囲にあるときに、軟磁性粉末の粉体抵抗がさらに向上することが確認できた。 Furthermore, as shown in Tables 1 to 5, it was confirmed that the powder resistance of the soft magnetic powder is further improved when the range is preferably 1.1≦Fe3/Fe2≦41.0, more preferably 1.2≦Fe3/Fe2≦35.0, and even more preferably 1.3≦Fe3/Fe2≦20.0.
　また表１～表５に示すように、３５．０≦Ｆｅ３≦９５．０、さらに好ましくは３７．０≦Ｆｅ３≦９３．０、さらに好ましくは４０．０≦Ｆｅ３≦９２．０、さらに好ましくは５５．０≦Ｆｅ３≦７０．０の範囲にあるときに、軟磁性粉末の粉体抵抗がさらに向上することが確認できた。 Also, as shown in Tables 1 to 5, it was confirmed that the powder resistance of the soft magnetic powder is further improved when the range is 35.0≦Fe3≦95.0, more preferably 37.0≦Fe3≦93.0, even more preferably 40.0≦Fe3≦92.0, and even more preferably 55.0≦Fe3≦70.0.
　また表１～表５に示すように、第１の被覆部１１、第２の被覆部１２および第３の被覆部１３を有する被覆部１０の合計厚みＴは、好ましくは５～２５０ｎｍ、さらに好ましくは６～１２５ｎｍ、さらに好ましくは１０ｎｍ～１１０ｎｍ程度に薄く、被覆部１０の厚みが仮に５０ｎｍ以下、４０ｎｍ以下、３０ｎｍ以下であっても、１０の５乗以上、１０の６乗以上、１０の７乗以上あるいは１０の８乗以上の抵抗率（Ω・ｃｍ）を有する軟磁性金属粉末を得ることができることが確認できた。 As shown in Tables 1 to 5, the total thickness T of the coating 10 including the first coating 11, the second coating 12, and the third coating 13 is preferably thin, about 5 to 250 nm, more preferably 6 to 125 nm, and even more preferably 10 nm to 110 nm. Even if the thickness of the coating 10 is 50 nm or less, 40 nm or less, or 30 nm or less, it has been confirmed that a soft magnetic metal powder having a resistivity (Ω-cm) of 10 to the power of 5 or more, 10 to the power of 6 or more, 10 to the power of 7 or more, or 10 to the power of 8 or more can be obtained.
　また表１～表５に示すように、第１の被覆部１１の厚みｔ１は、好ましくは０．８ｎｍ以上、さらに好ましくは１．１ｎｍ以上であり、第２の被覆部１２の厚みｔ２は、好ましくは１ｎｍ以上、さらに好ましくは１．７ｎｍ以上、さらに好ましくは２．４ｎｍ以上であり、第３の被覆部１３の厚みは、好ましくは１ｎｍ以上、さらに好ましくは１．５ｎｍ以上であることが確認できた。 As shown in Tables 1 to 5, it was confirmed that the thickness t1 of the first coating portion 11 is preferably 0.8 nm or more, and more preferably 1.1 nm or more, the thickness t2 of the second coating portion 12 is preferably 1 nm or more, and more preferably 1.7 nm or more, and more preferably 2.4 nm or more, and the thickness of the third coating portion 13 is preferably 1 nm or more, and more preferably 1.5 nm or more.
　１…被覆粒子
　　１ａ…第１の粒子
　　１ｂ…第２の粒子
　　１ｃ…第３の粒子
　２…軟磁性金属粒子
　１０…被覆部
　　１１…第１の被覆部
　　１２…第２の被覆部
　　１３…第３の被覆部
　　１４…第４の被覆部（内側被覆部）
　　１５…第５の被覆部（外側被覆部）
１００…圧粉磁心 REFERENCE SIGNS LIST 1... Coated particle 1a... First particle 1b... Second particle 1c... Third particle 2... Soft magnetic metal particle 10... Coating portion 11... First coating portion 12... Second coating portion 13... Third coating portion 14... Fourth coating portion (inner coating portion)
15...Fifth covering portion (outer covering portion)
100...Powder core

Claims (6)

  1. 　Ｆｅを含む軟磁性金属粒子を有する軟磁性金属粉末であって、
    前記軟磁性金属粒子の表面は被覆部により覆われており、
    前記被覆部は、前記軟磁性金属粒子の表面から外側に向かって、少なくとも第１の被覆部と、第２の被覆部と、第３の被覆部とをこの順で有し、
    前記第１の被覆部におけるＦｅの濃度をＦｅ１、前記第２の被覆部におけるＦｅの濃度をＦｅ２、前記第３の被覆部におけるＦｅの濃度をＦｅ３とした場合に、
    Ｆｅ１＞Ｆｅ２およびＦｅ３＞Ｆｅ２
    の関係を満足する軟磁性金属粉末。     A soft magnetic metal powder having soft magnetic metal particles containing Fe,
    The surface of the soft magnetic metal particle is covered with a coating portion,
    The coating portion has at least a first coating portion, a second coating portion, and a third coating portion in this order from the surface of the soft magnetic metal particle toward the outside,
    When the concentration of Fe in the first coating portion is Fe1, the concentration of Fe in the second coating portion is Fe2, and the concentration of Fe in the third coating portion is Fe3,
    Fe1>Fe2 and Fe3>Fe2
    Soft magnetic metal powder that satisfies the relationship.
  2. 　１．１≦Ｆｅ１／Ｆｅ２≦３４．０　かつ　１．１≦Ｆｅ３／Ｆｅ２≦４１．０の関係をさらに満足する請求項１に記載の軟磁性金属粉末。 The soft magnetic metal powder according to claim 1, further satisfying the relationships 1.1≦Fe1/Fe2≦34.0 and 1.1≦Fe3/Fe2≦41.0.
  3. 　１．２≦Ｆｅ１／Ｆｅ２≦３２．０　かつ　１．２≦Ｆｅ３／Ｆｅ２≦３５．０の関係をさらに満足する請求項２に記載の軟磁性金属粉末。 The soft magnetic metal powder according to claim 2, further satisfying the relationships 1.2≦Fe1/Fe2≦32.0 and 1.2≦Fe3/Fe2≦35.0.
  4. 　前記第２の被覆部では、Ｓｉの濃度がＦｅの濃度よりも高く、前記第１の被覆部では、Ｓｉの濃度がＦｅの濃度よりも低い請求項１に記載の軟磁性金属粉末。 The soft magnetic metal powder according to claim 1, wherein the second coating portion has a higher Si concentration than the Fe concentration, and the first coating portion has a lower Si concentration than the Fe concentration.
  5. 　請求項１から４のいずれかに記載の軟磁性金属粉末を有する圧粉磁心。 A dust core comprising the soft magnetic metal powder according to any one of claims 1 to 4.
  6. 　請求項１から４のいずれかに記載の軟磁性金属粉末を有する電子部品。 An electronic component comprising the soft magnetic metal powder according to any one of claims 1 to 4.
PCT/JP2023/045347 2022-12-27 2023-12-18 Soft magnetic metal powder, powder magnetic core, and electronic component WO2024143050A1 (en)

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Publication number Priority date Publication date Assignee Title
JP2019009307A (en) * 2017-06-26 2019-01-17 太陽誘電株式会社 Magnetic material, electronic component, and manufacturing method of magnetic material
JP2021158261A (en) * 2020-03-27 2021-10-07 株式会社村田製作所 Metal magnetic particle, inductor, manufacturing method of metal magnetic particle, and manufacturing method of metal magnetic core

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2019009307A (en) * 2017-06-26 2019-01-17 太陽誘電株式会社 Magnetic material, electronic component, and manufacturing method of magnetic material
JP2021158261A (en) * 2020-03-27 2021-10-07 株式会社村田製作所 Metal magnetic particle, inductor, manufacturing method of metal magnetic particle, and manufacturing method of metal magnetic core

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