JP2001107104A - High permeability iron-base magnetic metal powder for powder magnetic core - Google Patents
High permeability iron-base magnetic metal powder for powder magnetic coreInfo
- Publication number
- JP2001107104A JP2001107104A JP28427599A JP28427599A JP2001107104A JP 2001107104 A JP2001107104 A JP 2001107104A JP 28427599 A JP28427599 A JP 28427599A JP 28427599 A JP28427599 A JP 28427599A JP 2001107104 A JP2001107104 A JP 2001107104A
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- Prior art keywords
- primary particles
- iron
- metal powder
- powder
- particles
- Prior art date
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- Pending
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- 239000000843 powder Substances 0.000 title claims abstract description 72
- 239000002184 metal Substances 0.000 title claims abstract description 57
- 229910052751 metal Inorganic materials 0.000 title claims abstract description 57
- 230000035699 permeability Effects 0.000 title claims abstract description 42
- 239000011164 primary particle Substances 0.000 claims abstract description 101
- 239000011163 secondary particle Substances 0.000 claims abstract description 46
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 103
- 239000000428 dust Substances 0.000 claims description 47
- 229910052742 iron Inorganic materials 0.000 claims description 37
- 239000002245 particle Substances 0.000 claims description 17
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 claims description 8
- 238000005520 cutting process Methods 0.000 claims description 6
- 239000000463 material Substances 0.000 claims description 5
- 229910000831 Steel Inorganic materials 0.000 claims description 4
- 239000010959 steel Substances 0.000 claims description 4
- 239000006247 magnetic powder Substances 0.000 claims 1
- 238000005054 agglomeration Methods 0.000 abstract 1
- 230000002776 aggregation Effects 0.000 abstract 1
- 230000000052 comparative effect Effects 0.000 description 22
- 238000000034 method Methods 0.000 description 10
- 229920005989 resin Polymers 0.000 description 9
- 239000011347 resin Substances 0.000 description 9
- 230000004907 flux Effects 0.000 description 6
- 238000010586 diagram Methods 0.000 description 5
- 238000000635 electron micrograph Methods 0.000 description 5
- 230000005415 magnetization Effects 0.000 description 5
- 238000005498 polishing Methods 0.000 description 5
- 238000005245 sintering Methods 0.000 description 5
- 229910000859 α-Fe Inorganic materials 0.000 description 5
- 230000007423 decrease Effects 0.000 description 4
- 239000007789 gas Substances 0.000 description 4
- 238000000465 moulding Methods 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 3
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- 230000001070 adhesive effect Effects 0.000 description 3
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 230000006835 compression Effects 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 230000005389 magnetism Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 229910044991 metal oxide Inorganic materials 0.000 description 2
- 150000004706 metal oxides Chemical class 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 238000004663 powder metallurgy Methods 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- 238000010298 pulverizing process Methods 0.000 description 2
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- ZZSNKZQZMQGXPY-UHFFFAOYSA-N Ethyl cellulose Chemical compound CCOCC1OC(OC)C(OCC)C(OCC)C1OC1C(O)C(O)C(OC)C(CO)O1 ZZSNKZQZMQGXPY-UHFFFAOYSA-N 0.000 description 1
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- 239000004571 lime Substances 0.000 description 1
- 239000000696 magnetic material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
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Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
- H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
- H01F41/0206—Manufacturing of magnetic cores by mechanical means
- H01F41/0246—Manufacturing of magnetic circuits by moulding or by pressing powder
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、チョークコイルな
どに用いられる、高周波領域での透磁率が高い圧粉磁芯
の材料となる鉄基磁性金属粉に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an iron-based magnetic metal powder used as a material for a dust core having a high magnetic permeability in a high frequency range, used for a choke coil or the like.
【０００２】[0002]
【従来の技術】高周波領域（１０kHz 〜1MHz）で用いら
れるチョークコイルなどには、フェライト焼結体磁芯、
圧粉磁芯などが用いられている。これらのうち、フェラ
イト焼結体磁芯は、飽和磁束密度が小さい。これに対し
て、磁性金属粉を接着剤と混合し圧縮成形して製造され
る圧粉磁芯は、フェライト焼結体磁芯より飽和磁束密度
が大きく、高温での焼結を必要としないため、製造コス
トがフェライト焼結体磁芯に比較して安価であるという
特徴を有している。2. Description of the Related Art A choke coil used in a high frequency range (10 kHz to 1 MHz) includes a ferrite sintered body magnetic core,
A dust core or the like is used. Among them, the ferrite sintered body core has a low saturation magnetic flux density. On the other hand, a dust core manufactured by mixing and compressing magnetic metal powder with an adhesive has a higher saturation magnetic flux density than a ferrite sintered body core and does not require sintering at high temperatures. In addition, the manufacturing cost is lower than that of the ferrite sintered body magnetic core.
【０００３】チョークコイルに用いる磁芯は、外部磁場
が作用する環境下で使用される。チョークコイルの磁芯
となるフェライト焼結体や圧粉磁芯内部の磁性金属粉な
どの磁性体は、外部磁場の向きに磁化されることが求め
られる。この時の磁化され易さが、透磁率( 透磁率＝磁
束密度／外部磁場の強さとして定義される）であり、高
い透磁率が要求されている。ところで、一般に磁性体内
に生じた磁化によって磁性体周辺に外部磁場と反対の方
向の磁場（反磁場）が形成される結果、外部磁場が弱め
られ、磁性体自体の磁化が妨げられ、磁性体内の磁束密
度が低下し、透磁率が低くなる問題がある。透磁率の改
善には、反磁場の低減が必要となる。A magnetic core used for a choke coil is used in an environment where an external magnetic field acts. A magnetic material such as a ferrite sintered body serving as a magnetic core of a choke coil or a magnetic metal powder inside a dust core is required to be magnetized in the direction of an external magnetic field. The ease of magnetization at this time is the magnetic permeability (permeability = magnetic flux density / the strength of the external magnetic field), and a high magnetic permeability is required. By the way, generally, as a result of the magnetization generated in the magnetic body, a magnetic field (reverse magnetic field) in the direction opposite to the external magnetic field is formed around the magnetic body, so that the external magnetic field is weakened, the magnetization of the magnetic body itself is hindered, There is a problem that the magnetic flux density decreases and the magnetic permeability decreases. To improve the magnetic permeability, it is necessary to reduce the demagnetizing field.
【０００４】この反磁場は、磁性金属粉の形状によって
変化し、針状や扁平状などの異方性が高い形状で、かつ
磁性体内の磁化の方向が、その長軸方向に一致した場合
に低下する。このような形状の磁性金属粉を用いて、長
軸が一方向に揃うように配向させて成形して得た圧粉磁
芯の場合、個々の金属粉の長軸方向に磁場を印加する条
件で使用すると圧粉磁芯内部での反磁場も小さくなり、
圧粉磁芯の透磁率は高くなる。The demagnetizing field varies depending on the shape of the magnetic metal powder. When the demagnetizing field has a highly anisotropic shape such as a needle shape or a flat shape, and the direction of magnetization in the magnetic body coincides with the major axis direction. descend. In the case of a dust core obtained by molding a magnetic metal powder having such a shape and orienting the major axis so as to be aligned in one direction, conditions for applying a magnetic field in the major axis direction of each metal powder When used in, the demagnetizing field inside the dust core becomes smaller,
The magnetic permeability of the dust core becomes higher.
【０００５】磁性金属粉を扁平化する方法として、特開
平１１−１４０５１２号公報に開示されている、溶融し
た金属をアトマイズ法によって粉末化し、金属粉がまだ
溶融しているうちに回転体の冷却体に衝突させて金属粉
を扁平化する方法（１）、特許第１６４７６０８号公報
に開示されている、磁性金属粉を振動ボールミルで粉砕
処理して扁平加工する方法（２）などが知られている。
これらの扁平状の磁性金属粉を用いて製造された圧粉磁
芯は、透磁率が改善されるが、高周波領域での透磁率が
低いという問題があった。As a method of flattening a magnetic metal powder, a molten metal is powdered by an atomizing method disclosed in Japanese Patent Application Laid-Open No. H11-140512, and cooling of a rotating body is performed while the metal powder is still molten. There are known a method of flattening a metal powder by colliding with a body (1), a method of flattening a magnetic metal powder by crushing with a vibrating ball mill, and a method of flattening the metal powder disclosed in Japanese Patent No. 1647608. I have.
Powder magnetic cores manufactured using these flat magnetic metal powders have improved magnetic permeability, but have a problem that magnetic permeability in a high-frequency region is low.
【０００６】[0006]
【発明が解決しようとする課題】本発明は、高周波領域
に至るまで、高い透磁率を維持する圧粉磁芯を製造でき
る磁性金属粉を得ることを目的とするものである。SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic metal powder capable of producing a dust core maintaining a high magnetic permeability up to a high frequency range.
【０００７】[0007]
【課題を解決するための手段】本発明の第一の発明は、
複数の一次粒子が集合した二次粒子からなる鉄基磁性金
属粉において、二次粒子が、（１）複数の扁平状一次粒
子の集合体、（２）複数の針状一次粒子の集合体、また
は（３）複数のひも状一次粒子が絡まってスポンジ状に
形成された集合体であることを特徴とする高透磁率の圧
粉磁芯用鉄基磁性金属粉である。Means for Solving the Problems The first invention of the present invention is:
In an iron-based magnetic metal powder comprising secondary particles in which a plurality of primary particles are aggregated, the secondary particles are (1) an aggregate of a plurality of flat primary particles, (2) an aggregate of a plurality of needle-like primary particles, Or (3) an iron-based magnetic metal powder for a dust core having a high magnetic permeability, which is an aggregate in which a plurality of string-like primary particles are entangled to form a sponge.
【０００８】好ましい第一の発明は、前記二次粒子の平
均粒径が４０〜１００μｍであることを特徴とする高透
磁率の圧粉磁芯用鉄基磁性金属粉である。A preferred first invention is an iron-based magnetic metal powder for a dust core having a high magnetic permeability, wherein the secondary particles have an average particle diameter of 40 to 100 μm.
【０００９】また、好ましい第一の発明は、前記一次粒
子の断面の平均短軸長が１〜５μｍ，平均アスペクト比
が２〜１００であることを特徴とする高透磁率の圧粉磁
芯用鉄基磁性金属粉である。A first aspect of the present invention is a powder magnetic core having a high magnetic permeability, characterized in that the primary particles have an average minor axis length of 1 to 5 μm in cross section and an average aspect ratio of 2 to 100. It is an iron-based magnetic metal powder.
【００１０】さらに、好ましい第一の発明は、前記スポ
ンジ状鉄基磁性金属粉が酸化鉄を還元して得たものであ
ることを特徴とする高透磁率の圧粉磁芯用鉄基磁性金属
粉である。[0010] Furthermore, a preferred first invention is the iron-based magnetic metal for dust cores having a high magnetic permeability, wherein the sponge-like iron-based magnetic metal powder is obtained by reducing iron oxide. Powder.
【００１１】また、好ましい第一の発明は、前記扁平状
一次粒子が、アトマイズ鉄粉を扁平加工することによっ
て得たものであることを特徴とする高透磁率の圧粉磁芯
用鉄基磁性金属粉である。In a preferred first invention, the flat primary particles are obtained by flattening atomized iron powder, and the iron-based magnetism for a dust core having a high magnetic permeability is provided. Metal powder.
【００１２】さらに、好ましい第一の発明は、前記針状
一次粒子が、溶製した鋼材を切削することによって得た
ものであることを特徴とする高透磁率の圧粉磁芯用鉄基
磁性金属粉である。Further, a preferred first invention is characterized in that the needle-like primary particles are obtained by cutting a smelted steel material, and the iron-based magnetism for a dust core having a high magnetic permeability is provided. Metal powder.
【００１３】[0013]
【発明の実施の形態】複数の一次粒子が集合してなる二
次粒子状鉄基磁性金属粉は、篩にかけて、その大きさを
一定値以下に調整できる。その平均粒径は４０〜１００
μｍ、好ましくは６０〜８０μｍである。平均粒径が１
００μｍを越えると、これを成形して得た圧粉磁芯は、
二次粒子内部での渦電流が過大になり、初透磁率（μi
/ μ0）が低下し、鉄損が増加するため、チョークコイ
ルなどの用途に不向きになる。平均粒径が４０μｍ未満
になると、二次粒子状磁性金属粉は圧縮成形性が低下す
る結果、圧粉磁芯の密度が低下し、透磁率が低下するの
で、これもチョークコイルなどの用途には不向きにな
る。BEST MODE FOR CARRYING OUT THE INVENTION A secondary particulate iron-based magnetic metal powder obtained by assembling a plurality of primary particles can be sieved to adjust its size to a certain value or less. Its average particle size is 40-100
μm, preferably 60 to 80 μm. Average particle size is 1
If it exceeds 00 μm, the dust core obtained by molding this
The eddy current inside the secondary particles becomes excessive, and the initial permeability (μ i
/ μ 0 ) decreases and iron loss increases, making it unsuitable for applications such as choke coils. When the average particle size is less than 40 μm, the secondary particulate magnetic metal powder has a reduced compression moldability, resulting in a reduced density of the dust core and a reduced magnetic permeability, which is also used in applications such as choke coils. Becomes unsuitable.
【００１４】本発明の一次粒子は、扁平状、針状、また
はひも状であるが、これらの形状は、一次粒子断面の平
均長軸長と、それに対して直交する平均短軸長の比で定
義される平均アスペクト比によって規定される。一次粒
子の長軸長および短軸長は、二次粒子状金属粉を樹脂製
品に埋め込んだ後、樹脂製品を切断し、さらにその切断
面を研磨し、切断面上に観察される任意の二次粒子状金
属粉断面を光学顕微鏡で観察し、二次粒子状金属粉断面
を構成する複数の一次粒子の断面を観察することにより
測定される。The primary particles of the present invention are flat, needle-like or cord-like, and these shapes are defined by the ratio of the average major axis length of the primary particle cross section to the average minor axis length orthogonal to the primary particle section. Defined by the defined average aspect ratio. The major axis length and the minor axis length of the primary particles are determined by embedding the secondary particulate metal powder in the resin product, cutting the resin product, further polishing the cut surface, and arbitrarily measuring the length of the secondary particle observed on the cut surface. It is measured by observing the cross section of the secondary particulate metal powder with an optical microscope and observing the cross section of a plurality of primary particles constituting the secondary particulate metal powder cross section.
【００１５】図１ａに、扁平状一次粒子が複数集合して
なる二次粒子の断面、図１ｂに、針状一次粒子が複数集
合してなる二次粒子の断面、および図１ｃに、ひも状一
次粒子が複数絡まってなる二次粒子の断面を表す模式図
を示す。各図に示されるように、二次粒子を構成する複
数の一次粒子１０個の各々について、長軸長と短軸長を
測定し、その平均を求めたものが、平均長軸長および平
均短軸長である。ひも状一次粒子については、長軸が直
線でないため、図１ｃに示したように、最長の長さを長
軸長、最短の幅を短軸長とした。FIG. 1a shows a cross section of a secondary particle formed by a plurality of flat primary particles, FIG. 1b shows a cross section of a secondary particle formed by a plurality of acicular primary particles, and FIG. The schematic diagram showing the cross section of the secondary particle which a plurality of primary particles are entangled is shown. As shown in each figure, the major axis length and the minor axis length were measured for each of a plurality of primary particles constituting the secondary particles, and the average was obtained. The axis length. For the cord-like primary particles, the long axis was not a straight line, so the longest length was the long axis length and the shortest width was the short axis length, as shown in FIG. 1c.
【００１６】好ましい一次粒子の平均アスペクト比は２
〜１００である。平均アスペクト比が２未満であると、
二次粒子状金属粉を加圧成形して得られる圧粉磁芯は、
内部反磁場の低下が十分でなくなる。一方平均アスペク
ト比が１００を越えると、一次粒子の均一な加工（扁平
加工・針状加工）が困難となり、加工コストが高くなる
ため好ましくない。The preferred primary particles have an average aspect ratio of 2
~ 100. If the average aspect ratio is less than 2,
The dust core obtained by press-molding the secondary particulate metal powder,
The internal demagnetizing field is not sufficiently reduced. On the other hand, if the average aspect ratio exceeds 100, uniform processing (flattening / needle processing) of the primary particles becomes difficult, and processing costs increase, which is not preferable.
【００１７】前記平均短軸長は１〜５μｍ、好ましくは
２〜５μｍである。平均短軸長が５μｍを越えると、こ
れを成形してなる圧粉磁芯は、十分な内部反磁場の低下
が得られない。一方平均短軸長が１μｍ未満であると、
一次粒子の加工がコスト高になり、好ましくない。The average minor axis length is 1 to 5 μm, preferably 2 to 5 μm. If the average short axis length exceeds 5 μm, the dust core obtained by molding the same cannot have a sufficient reduction in the internal demagnetizing field. On the other hand, if the average short axis length is less than 1 μm,
Processing of primary particles is not preferable because it increases costs.
【００１８】前記一次粒子の平均長軸長は、前記一次粒
子の平均短軸長の範囲（１〜５μｍ）と前記一次粒子の
平均アスペクト比の好ましい範囲（２〜１００）から２
〜５００μｍとなる。しかし、図１ａ〜ｃに示した二次
粒子の模式図から明らかなように、前記二次粒子の平均
粒径の好ましい範囲を実現するためには、一次粒子の平
均長軸長は、二次粒子の平均粒径以下になる必要があ
る。したがって、二次粒子内部の一次粒子の平均長軸長
の上限は二次粒子の平均粒子径によって限定されるた
め、その範囲は２〜１００μｍにならざるを得ないこと
がわかる。さらに好ましくは２〜８０μｍの範囲であ
る。一次粒子の平均長軸長は一次粒子を篩分級して調整
する。The average major axis length of the primary particles is 2 from the average minor axis length range of the primary particles (1 to 5 μm) and the preferred range of the average aspect ratio of the primary particles (2 to 100).
５００500 μm. However, as is apparent from the schematic diagrams of the secondary particles shown in FIGS. 1A to 1C, in order to realize a preferable range of the average particle size of the secondary particles, the average major axis length of the primary particles is It is necessary that the average particle size of the particles be equal to or smaller than the average particle size. Therefore, since the upper limit of the average major axis length of the primary particles inside the secondary particles is limited by the average particle diameter of the secondary particles, it is understood that the range must be 2 to 100 μm. More preferably, it is in the range of 2 to 80 μm. The average major axis length of the primary particles is adjusted by sieving the primary particles.
【００１９】複数の一次粒子が集合してなる二次粒子
は、一般的には以下のように製造される。扁平状の一次
粒子は、アトマイズ鉄粉をボールミル、アトライタ、デ
ィスクミルなどの粉砕処理を施すことにより、あるいは
圧延処理を施すことにより、機械的に扁平加工して製造
される。そのアトマイズ鉄粉は、溶鋼に気体または水ジ
ェットを吹き付け、粉末化することにより製造される、
内部が稠密で、外形は球状に近い粉末である。アトマイ
ズ鉄粉は、Ｃ、Ｃｏ、Ｎｉ、Ｓｉ，Ａｌとその他の不可
避的不純物を含有する。金属粉の圧縮性を低下させない
範囲で、これらの成分を、鉄損を下げ、透磁率を向上さ
せることを目的として、粉末化の前に溶鋼に添加しても
よい。The secondary particles formed by assembling a plurality of primary particles are generally produced as follows. The flat primary particles are manufactured by mechanically flattening atomized iron powder by subjecting it to a pulverizing process such as a ball mill, an attritor, or a disk mill, or by performing a rolling process. The atomized iron powder is manufactured by spraying gas or water jet on molten steel and pulverizing,
The inside is dense and the outer shape is a nearly spherical powder. Atomized iron powder contains C, Co, Ni, Si, Al and other unavoidable impurities. To the extent that the compressibility of the metal powder is not reduced, these components may be added to molten steel before powderization for the purpose of reducing iron loss and improving magnetic permeability.
【００２０】扁平状一次粒子は、例えば、造粒などによ
り粒子同士を結着させ、二次粒子に形成される。図２は
扁平状のアトマイズ鉄粉（一次粒子）同士が結着し、二
次粒子を形成している様子を示す電子顕微鏡写真（倍率
４００倍）である。The flat primary particles are formed into secondary particles by binding the particles together by, for example, granulation. FIG. 2 is an electron micrograph (400 times magnification) showing a state in which flat atomized iron powder (primary particles) are bound together to form secondary particles.
【００２１】前記の結着とは、力を加えないと一次粒子
間が相互に離れないようにすることである。これは、一
次粒子が点状（図４に示すように、面全体あるいは線全
体ではなく、点状の広がりしか持たない状態）に粘着し
ている状態である。これは、（１）圧着、（２）個々の
一次粒子間を接着剤などにより接着、（３）一次粒子間
を一次粒子を構成する物質を仮焼結させ、拡散させるこ
とで接合する方法などにより実現される。ここで圧着と
は、例えば、多数の一次粒子をガスを用いた流動層で高
速流動させ、粒子相互を衝突させ、その際に粒子相互の
形状を変形、噛みこみを起こさせて結着する方法などを
例示することができる。The above-mentioned binding is to prevent the primary particles from separating from each other unless a force is applied. This is a state in which the primary particles are adhered in a point-like manner (as shown in FIG. 4, not in the entire surface or in the entire line, but in the point-like spread). This involves (1) pressure bonding, (2) bonding between individual primary particles with an adhesive or the like, (3) temporary sintering of the material constituting the primary particles between the primary particles and bonding by diffusing. Is realized by: Here, press bonding means, for example, a method in which a large number of primary particles are made to flow at high speed in a fluidized bed using gas, and the particles collide with each other. And the like.
【００２２】接着剤としては、水溶性物質であるポリビ
ニルアルコール、メチルセルロース、ポリアクリルアミ
ドなど、非水溶性物質であるパラフィンワックス、ポリ
エチレングリコール、ポリビニルピロリドン、ヒドロキ
シプロピルセルロース、エチルセルロース、アセチルセ
ルロース、ニトロセルロース、酢酸ビニル樹脂などが好
適である。また、エポキシ樹脂、フェノール樹脂、イミ
ド樹脂などの熱硬化性樹脂、ポリアミド、ふっ素樹脂な
どの熱可塑性樹脂なども好適である。Examples of the adhesive include water-insoluble substances such as polyvinyl alcohol, methylcellulose, and polyacrylamide, and water-insoluble substances such as paraffin wax, polyethylene glycol, polyvinylpyrrolidone, hydroxypropylcellulose, ethylcellulose, acetylcellulose, nitrocellulose, and acetic acid. Vinyl resins and the like are preferred. Further, thermosetting resins such as epoxy resin, phenol resin and imide resin, and thermoplastic resins such as polyamide and fluororesin are also suitable.
【００２３】仮焼結とは、温度、雰囲気、露点を適切に
制御して熱処理を行い、粒子面ではなく、点でしか結着
しておらず、かつ粒子の結着していない部分は表面が酸
化されていることで、加圧による接触が起きても面の間
は互いに絶縁されるように、結着させることである。図
２は、扁平状のアトマイズ鉄粉（一次粒子）同士を仮焼
結後、解砕することによって得た二次粒子の電子顕微鏡
写真（倍率４００倍）である。The term “temporary sintering” means that heat treatment is performed by appropriately controlling the temperature, atmosphere, and dew point. Is oxidized so that the surfaces are insulated from each other even if contact by pressure occurs. FIG. 2 is an electron micrograph (400-fold magnification) of secondary particles obtained by sintering and flattening flat atomized iron powders (primary particles).
【００２４】針状一次粒子からなる二次粒子は、扁平状
一次粒子からなる二次粒子の製造と同様に、針状一次粒
子を前記方法で結着させることにより製造するのが好ま
しい。針状一次粒子は、溶製した金属材を切削して得る
か、線材を切断加工して得ることができる。The secondary particles composed of the acicular primary particles are preferably produced by binding the acicular primary particles in the same manner as in the production of the secondary particles composed of the flat primary particles. The needle-like primary particles can be obtained by cutting a molten metal material or by cutting a wire material.
【００２５】ひも状一次粒子からなる二次粒子は、鉄基
金属酸化物をＣＯ還元することによって得られる。鉄基
金属酸化物を還元すると、還元された金属結晶が複数の
ひも状に成長し、これが成長の過程で絡み合ってスポン
ジ状二次粒子を形成する。The secondary particles composed of string-like primary particles can be obtained by reducing an iron-based metal oxide with CO. When the iron-based metal oxide is reduced, the reduced metal crystals grow into a plurality of strings, which are entangled during the growth to form sponge-like secondary particles.
【００２６】還元を急速に進行させると、ひも状一次粒
子の径方向への成長を抑制し、平均アスペクト比を増大
させることができる。急速還元には、還元温度を高くす
る手段か、ＣＯガス濃度を高くする手段が有効である。
還元鉄粉は、通常Ｃ、Ｃｏ、Ｎｉ、Ｍｎ，Ｓｉ，Ａｌと
その他の不可避的不純物を含有している。When the reduction proceeds rapidly, it is possible to suppress the growth of the string-like primary particles in the radial direction and increase the average aspect ratio. For rapid reduction, means for increasing the reduction temperature or means for increasing the CO gas concentration are effective.
The reduced iron powder usually contains C, Co, Ni, Mn, Si, Al and other unavoidable impurities.
【００２７】なおスポンジ状磁性金属粉は、すでに本発
明で云う一次粒子が集合した二次粒子を構成している形
態であり、さらなる結着のための処置・加工を行なわず
とも、所望の磁気特性を得ることができる。勿論、結着
のための処理をすることは差支えない。図３は、本発明
で得られたスポンジ状磁性金属粉（二次粒子）の電子顕
微鏡写真（倍率５００倍）である。ひも状一次粒子が複
数絡まって二次粒子を形成している様子が観察される。The sponge-like magnetic metal powder is in the form of secondary particles in which the primary particles are aggregated as described in the present invention, and the desired magnetic metal powder can be obtained without further treatment or processing for binding. Properties can be obtained. Of course, processing for binding may be performed. FIG. 3 is an electron micrograph (500 times magnification) of the sponge-like magnetic metal powder (secondary particles) obtained in the present invention. It is observed that a plurality of string-like primary particles are entangled to form secondary particles.
【００２８】前記の方法で得られた複数の一次粒子が結
着してなる二次粒子からなる磁性金属粉は、圧縮成形に
より圧粉磁芯に成形されるが、圧縮圧は２８６〜６８６
MPaが好ましい。純鉄系の金属粉を用いる場合は、圧粉
磁芯の密度が６．０Ｍｇ／ｍ 3 以上、好ましくは６．９
Ｍｇ／ｍ3 以上であると特に高い透磁率を示す。The plurality of primary particles obtained by the above method are combined.
Magnetic metal powder consisting of secondary particles adhered to
It is more compacted into a dust core, but the compression pressure is 286-686.
MPa is preferred. When using pure iron-based metal powder,
Magnetic core density of 6.0 Mg / m ThreeAbove, preferably 6.9
Mg / mThreeIf it is above, a particularly high magnetic permeability is exhibited.
【００２９】次に、平均アスペクト比の高い複数の一次
粒子が結着してなる二次粒子状磁性金属粉から作られた
圧粉磁芯において、透磁率が向上する理由を述べる。ス
ポンジ状金属粉から得た圧粉磁芯の断面を研磨し、観察
すると、ひも状一次粒子が加圧方向に対して垂直方向に
良く配向している。扁平状磁性金属粉や針状磁性金属粉
を一次粒子とする二次粒子を用いた圧粉磁芯の断面から
も、扁平状一次粒子や針状一次粒子の長軸が加圧方向に
対して垂直方向に配向していることが観察される。これ
は、ひも状、針状や扁平状の一次粒子が加圧によって容
易に変形し、長軸が加圧方向に対し垂直方向に配向する
ためと推考される。Next, the reason why the magnetic permeability of a dust core made of a secondary particulate magnetic metal powder formed by binding a plurality of primary particles having a high average aspect ratio is improved will be described. When the cross section of the dust core obtained from the sponge-like metal powder is polished and observed, the string-like primary particles are well oriented in the direction perpendicular to the pressing direction. From the cross section of the dust core using the secondary particles having the flat magnetic metal powder or the needle-shaped magnetic metal powder as the primary particles, the long axis of the flat primary particles or the needle-shaped primary particles is in the pressing direction. It is observed that it is vertically oriented. This is presumed to be because the cord-like, needle-like, or flat primary particles are easily deformed by pressurization, and the major axis is oriented in a direction perpendicular to the pressurization direction.
【００３０】加えて、ノイズフィルターコアなどに多用
されるリングコアからなるトロイダルコアでは、内部の
磁場は円周方向に発生する。そのため、円の中心軸方向
に沿って加圧すると、圧粉磁芯を構成する磁性金属粉
（二次粒子）を構成する複数の一次粒子の長軸が円周方
向に配向して、トロイダルコアの内部磁場の方向と一致
し、よって内部反磁場が低下するのである。In addition, in a toroidal core composed of a ring core often used for a noise filter core or the like, an internal magnetic field is generated in a circumferential direction. Therefore, when pressure is applied along the center axis direction of the circle, the major axes of a plurality of primary particles constituting the magnetic metal powder (secondary particles) constituting the dust core are oriented in the circumferential direction, and the toroidal core is formed. , And the internal demagnetizing field decreases.
【００３１】[0031]
【実施例】（発明例１〜２、比較例１）酸化鉄に炭材と
石灰を配合調整し、加熱して発生するＣＯガスにより酸
化鉄を急速還元し、スポンジ状二次粒子からなる磁性鉄
粉を得た（発明例１、２）。また、従来の還元速度で還
元して粉末冶金用還元鉄粉（比較例１）を得た。これら
を篩分級して、表１に示す平均粒径の鉄粉を得た。EXAMPLES (Examples 1 and 2 and Comparative Example 1) A carbon material and lime were mixed and adjusted with iron oxide, and the iron oxide was rapidly reduced by CO gas generated by heating. Iron powder was obtained (Inventive Examples 1 and 2). In addition, reduction was performed at a conventional reduction rate to obtain reduced iron powder for powder metallurgy (Comparative Example 1). These were sieved and classified to obtain iron powder having an average particle size shown in Table 1.
【００３２】上記鉄粉を樹脂製品に埋め込み、切断し、
断面を研磨後、光学顕微鏡を用いて鉄粉の二次粒子断面
の観察を行ない、スポンジ状二次粒子を構成する、ひも
状一次粒子の断面平均長軸長と平均短軸長を測定した。
ひも状一次粒子の平均アスペクト比は、上記の平均長軸
長と平均短軸長の比として求めた。上記二次粒子の平均
粒径、一次粒子の平均短軸長、平均アスペクト比および
見掛密度を表１に示した。The above iron powder is embedded in a resin product, cut, and
After polishing the cross section, the cross section of the secondary particles of the iron powder was observed using an optical microscope, and the average long major axis length and the average short minor axis length of the string primary particles constituting the sponge secondary particles were measured.
The average aspect ratio of the cord-like primary particles was determined as the ratio of the average major axis length to the average minor axis length. Table 1 shows the average particle size of the secondary particles, the average minor axis length of the primary particles, the average aspect ratio, and the apparent density.
【００３３】次に、鉄粉をそれぞれ、圧縮圧６８６MPa
で圧縮成形することにより、外径を３８ｍｍ、内径２５
ｍｍ、厚さ６．２ｍｍのリング状圧粉磁芯を成形した。
得られた圧粉磁芯の周波数１０kHz での、交流初透磁率
をμi / μo （μo ：真空透磁率）と圧粉体密度を測定
した。なお交流初透磁率は初磁化曲線の原点近傍におい
て、下記式（式中、Ｈ：交流磁界強さ、Ｂ：交流磁束密
度）によって与えられる極限値である。Next, each of the iron powders was compressed at a pressure of 686 MPa.
The outer diameter is 38 mm and the inner diameter is 25
A ring-shaped dust core having a thickness of 6.2 mm and a thickness of 6.2 mm was formed.
At the frequency of 10 kHz, the obtained powder magnetic core was measured for its initial AC permeability μ i / μ o (μ o : vacuum permeability) and green compact density. The AC initial permeability is a limit value given by the following equation (where H: AC magnetic field strength, B: AC magnetic flux density) near the origin of the initial magnetization curve.
【００３４】[0034]
【数１】 (Equation 1)
【００３５】交流初透磁率は、上記の圧粉磁芯に直径
０．６ｍｍのホルマル被覆電線を均等間隔で１１周巻き
付けたコアについて、インピーダンスメーター（Hewlet
t-Packard 社製 HP-4284A) を用い、ＪＩＳ Ｃ２５６
１に準拠した手法で測定した。交流初透磁率が１０kHz
での交流初透磁率の８０％になる周波数を、臨界周波数
ｆcrとして算出した。臨界周波数は、高周波数領域での
鉄損が小さいほど高い値を示すため、高周波数領域での
鉄損を示す指標となる。The initial AC permeability was measured by using an impedance meter (Hewlet) for a core obtained by winding a formal-coated wire having a diameter of 0.6 mm around the powder magnetic core 11 times at equal intervals.
t-Packard HP-4284A) using JIS C256
It measured by the method based on No. 1. AC permeability is 10kHz
Was calculated as the critical frequency fcr . Since the critical frequency shows a higher value as the iron loss in the high frequency region is smaller, it becomes an index indicating the iron loss in the high frequency region.
【００３６】鉄損は、上記交流初透磁率を測定する際に
使用した圧粉磁芯に、直径０．６ｍｍのホルマル被覆導
線を均等間隔に１次側線、２次側線として各々４０回巻
線した試料について、Ｂ−Ｈアナライザー（Hewlett-Pa
ckard 社製 E-5060A)を用い、周波数１０kHz 、磁束密
度０．１Ｔの条件で測定した。The iron loss is determined by winding a formal-coated conductor having a diameter of 0.6 mm on the dust core used for measuring the AC initial permeability as a primary side wire and a secondary side wire at equal intervals 40 times each. About the sample thus obtained, use a BH analyzer (Hewlett-Pa
The measurement was carried out under the conditions of a frequency of 10 kHz and a magnetic flux density of 0.1 T using a Cckard E-5060A).
【００３７】圧粉磁芯の密度は、秤によって求められた
重量を、マイクロメータにより測定した外径、内径、厚
さを用いて求められる体積で除すことで算出した。上記
の圧粉磁芯の特性を表１に示した。The density of the dust core was calculated by dividing the weight determined by the scale by the volume determined using the outer diameter, inner diameter, and thickness measured by a micrometer. Table 1 shows the characteristics of the dust cores.
【００３８】発明例１、２および比較例１の磁性鉄粉
は、いずれの場合も、粒子の内部が、複数のひも状一次
粒子が絡まって二次粒子を形成しているように観察され
た。In each case, the magnetic iron powders of Inventive Examples 1 and 2 and Comparative Example 1 were observed such that a plurality of string-like primary particles were entangled to form secondary particles inside the particles. .
【００３９】発明例１、２のひも状一次粒子の平均短軸
長は５．０μｍ以下であり、比較例１の１１．０μｍ以
下より小さい。それぞれのひも状一次粒子の平均アスペ
クト比は、順に６、５、３である。The average minor axis length of the cord-like primary particles of Invention Examples 1 and 2 is 5.0 μm or less, and is smaller than 11.0 μm or less of Comparative Example 1. The average aspect ratio of each cord-like primary particle is 6, 5, and 3, respectively.
【００４０】発明例１、２のひも状一次粒子の交流初透
磁率は８０以上であり、比較例１の７６より大きい。発
明例１、２のひも状一次粒子の鉄損はそれぞれ、３６Ｗ
／ｋｇ、３５Ｗ／ｋｇであり、比較例１の４１Ｗ／ｋｇ
より低下していた。発明例１、２のひも状一次粒子の臨
界周波数は、それぞれ０．８０MHz 、０．６０MHz であ
り、比較例１の０．４８MHz を上回っている。The AC initial permeability of the cord-like primary particles of Invention Examples 1 and 2 is 80 or more, which is larger than 76 of Comparative Example 1. The core loss of the string-like primary particles of Invention Examples 1 and 2 was 36 W, respectively.
/ Kg, 35 W / kg, 41 W / kg of Comparative Example 1
Was lower. The critical frequencies of the string-like primary particles of Inventive Examples 1 and 2 are 0.80 MHz and 0.60 MHz, respectively, which is higher than 0.48 MHz of Comparative Example 1.
【００４１】以上から、本発明のひも状一次粒子の平均
短軸長が５．０μｍ以下になっている鉄粉を用いた発明
例１、２の圧粉磁芯は、従来技術である比較例１の圧粉
磁芯に比べ、高交流初透磁率、低鉄損、高臨界周波数で
あり、高周波特性が優れている圧粉磁芯であることが分
かる。As described above, the dust cores of Invention Examples 1 and 2 using iron powder in which the average short-axis length of the string-like primary particles is 5.0 μm or less are comparative examples of the prior art. As compared with the dust core of No. 1, the dust core has a high AC initial permeability, a low iron loss, a high critical frequency, and is excellent in high frequency characteristics.
【００４２】鉄損が低下し、また臨界周波数が上昇した
理由としては、一次粒子の径が小さくなることで、一次
粒子内部の渦電流損が小さくなったことと、一次粒子の
表面に形成される酸化膜によって互いに絶縁されること
で、一次粒子間の渦電流損が小さくなったためと推測さ
れる。The iron loss was reduced and the critical frequency was increased because the diameter of the primary particles was reduced, so that the eddy current loss inside the primary particles was reduced and that the primary particles were formed on the surface of the primary particles. It is presumed that the eddy current loss between the primary particles was reduced by being insulated from each other by the oxide films.
【００４３】 [0043]
【００４４】（発明例３〜４、比較例２）水アトマイズ
鉄粉をボールミルで扁平加工し、目開きが４５μｍの篩
で分級し、扁平状一次粒子を得た。さらに、水蒸気含有
水素雰囲気（水蒸気露点６０℃）中で、８００℃で１時
間、仮焼結した。この後、得られたケーキの鉄粉を解砕
し、目開き１８０μｍの篩で分級して、扁平状一次粒子
が結着した二次粒子の鉄粉を得た（発明例３）。(Inventive Examples 3 to 4, Comparative Example 2) Water atomized iron powder was flattened with a ball mill and classified with a sieve having a mesh size of 45 μm to obtain flat primary particles. Furthermore, presintering was performed at 800 ° C. for 1 hour in a hydrogen atmosphere containing water vapor (steam dew point: 60 ° C.). Thereafter, the iron powder of the obtained cake was crushed and classified with a sieve having an opening of 180 μm to obtain iron powder of secondary particles to which flat primary particles were bound (Invention Example 3).
【００４５】軟鋼の溶製棒材を切削して、平均直径４．
０μｍの針状一次粒子を得た。これを発明例３と同様の
条件で仮焼結し、針状一次粒子が結着した二次粒子を得
た（発明例４）。鉄粉（二次粒子）の粉体特性と、一次
粒子の平均アスペクト比を表２に示した。比較のため、
粉末冶金用アトマイズ鉄粉（比較例２）およびその鉄粉
を扁平加工した鉄粉（比較例３）の特性を表２に示し
た。なお比較例３の鉄粉は振動ボールミルで、加工の
上、目開き１８０μｍの篩で分級し、さらに水蒸気含有
水素雰囲気（水蒸気露点６０℃）中で、８００℃で１時
間熱処理した。これらの鉄粉を、発明例１の時と同様の
手順で圧粉磁芯に成形し、同様に特性を測定した。結果
を表２に示した。An average diameter of a wrought bar of mild steel was cut to 4.
Acicular primary particles of 0 μm were obtained. This was pre-sintered under the same conditions as in Invention Example 3 to obtain secondary particles to which needle-like primary particles were bound (Invention Example 4). Table 2 shows the powder characteristics of the iron powder (secondary particles) and the average aspect ratio of the primary particles. For comparison,
Table 2 shows the characteristics of atomized iron powder for powder metallurgy (Comparative Example 2) and iron powder obtained by flattening the iron powder (Comparative Example 3). The iron powder of Comparative Example 3 was processed by a vibration ball mill, classified with a sieve having an opening of 180 μm, and further heat-treated at 800 ° C. for 1 hour in a hydrogen atmosphere containing water vapor (steam dew point: 60 ° C.). These iron powders were formed into a dust core in the same procedure as in Inventive Example 1, and the characteristics were measured in the same manner. The results are shown in Table 2.
【００４６】二次粒子内部の観察から、発明例３の鉄粉
には、扁平状一次粒子の断面が観察された。この扁平状
一次粒子の平均径は３．６μｍであり、平均アスペクト
比は５であった。また、発明例４の鉄粉には、針状一次
粒子が確認された。この針状一次粒子の平均径は４．０
μｍであり、平均アスペクト比は１０であった。比較例
２、３の鉄粉では、鉄粉内部がさらに分断した構造は確
認されなかった。比較例２、３の鉄粉の幅を一次粒子径
と見なしたときの値はそれぞれ２０．０μｍおよび１
７．０μｍであった。またアスペクト比はそれぞれ１お
よび６であった。From the observation of the inside of the secondary particles, a cross section of flat primary particles was observed in the iron powder of Invention Example 3. The average diameter of the flat primary particles was 3.6 μm, and the average aspect ratio was 5. Further, needle-like primary particles were confirmed in the iron powder of Invention Example 4. The average diameter of the acicular primary particles is 4.0.
μm, and the average aspect ratio was 10. In the iron powders of Comparative Examples 2 and 3, a structure in which the inside of the iron powder was further divided was not confirmed. When the width of the iron powder in Comparative Examples 2 and 3 was regarded as the primary particle diameter, the values were 20.0 μm and 1 respectively.
It was 7.0 μm. The aspect ratios were 1 and 6, respectively.
【００４７】次に、それぞれの圧粉磁芯の密度を測定し
た。発明例３の圧粉磁芯は、比較例２、３の圧粉磁芯に
比べ、密度が０．０７〜０．０９Ｍｇ／ｍ3 低くなっ
た。発明例４の圧粉磁芯のそれは比較例２と同等であっ
た。発明例３の圧粉磁芯の交流初透磁率は、比較例２、
３の圧粉磁芯に比べ、密度が低かったにもかかわらず、
８０と相当に大きく、発明例４の圧粉磁芯のそれは８８
と一層大きかった。Next, the density of each dust core was measured. The dust core of Inventive Example 3 had a density lower by 0.07 to 0.09 Mg / m 3 than the dust cores of Comparative Examples 2 and 3 . The dust core of Inventive Example 4 was equivalent to Comparative Example 2. The AC initial magnetic permeability of the dust core of Invention Example 3 was the same as Comparative Example 2,
Despite having a lower density than the dust core of No.3,
80, and that of the dust core of Invention Example 4 is 88
It was even bigger.
【００４８】圧粉磁芯の密度を大きくするだけでなく、
圧粉体内部の粒子の内部反磁場を小さくするような構造
をもたせるのが好ましいが、それは、比較例２と発明例
３、４の比較から明瞭である。アトマイズ鉄粉を扁平化
して得た扁平状一次粒子、あるいは溶製材を切削するこ
とで得た針状一次粒子のような内部反磁場を低減させる
形状を有する一次粒子が、結着してできる二次粒子構造
を持ち、その扁平状あるいは針状一次粒子の平均径が
５．０μｍ以下である鉄粉を用いると、より高い交流初
透磁率を持つ圧粉磁芯が得られることが分かる。In addition to increasing the density of the dust core,
It is preferable to provide a structure that reduces the internal demagnetizing field of the particles inside the green compact, which is clear from a comparison between Comparative Example 2 and Invention Examples 3 and 4. Flat primary particles obtained by flattening atomized iron powder, or primary particles having a shape that reduces the internal demagnetizing field, such as needle-shaped primary particles obtained by cutting an ingot, are formed by binding. It can be seen that a powder magnetic core having a higher AC initial permeability can be obtained by using iron powder having a secondary particle structure and having an average diameter of the flat or acicular primary particles of 5.0 μm or less.
【００４９】また、比較例３と発明例３、４の比較から
分かるように、平均アスペクト比の高い一次粒子からな
る二次粒子構造を持たせると、従来公知であったアトマ
イズ法で製造した鉄粉よりも高い透磁率をもつ圧粉磁芯
が得られた。Further, as can be seen from the comparison between Comparative Example 3 and Invention Examples 3 and 4, when a secondary particle structure composed of primary particles having a high average aspect ratio is provided, iron produced by a conventionally known atomizing method is provided. A dust core having a higher magnetic permeability than the powder was obtained.
【００５０】発明例３、４の鉄損は、それぞれ３６Ｗ／
ｋｇ、３５Ｗ／ｋｇで、比較例２の４５Ｗ／ｋｇ、比較
例３の４１Ｗ／ｋｇより低い。発明例３、４の臨界周波
数は、比較例２の場合より高い値を示したことから、二
次粒子構造が臨界周波数の向上に有効であることが分か
る。The iron losses of Invention Examples 3 and 4 were 36 W /
kg, 35 W / kg, lower than 45 W / kg in Comparative Example 2 and 41 W / kg in Comparative Example 3. The critical frequencies of Inventive Examples 3 and 4 were higher than those of Comparative Example 2, indicating that the secondary particle structure is effective for improving the critical frequency.
【００５１】すなわち、原料が内部稠密な鉄粉でも、内
部反磁場が小さくなるような形状に賦形した上で、それ
らを仮焼結により結着させて二次粒子構造を持たせるこ
とで、原料の鉄粉そのままを用いた場合よりも、鉄損が
低くなり、かつ交流初透磁率も高い圧粉磁芯が得られ
た。That is, even if the raw material is an internal dense iron powder, it is shaped into such a shape that the internal demagnetizing field is reduced, and then they are bound by temporary sintering to have a secondary particle structure. As compared with the case of using the raw iron powder as it is, a dust core having a lower iron loss and a higher AC initial permeability was obtained.
【００５２】 [0052]
【００５３】[0053]
【発明の効果】本発明の磁性金属粉は、反磁場が小さい
ので、高周波領域での透磁率が高い圧粉磁芯に成形さ
れ、チョークコイルなどに好適である。Since the magnetic metal powder of the present invention has a small demagnetizing field, it is formed into a dust core having a high magnetic permeability in a high frequency range, and is suitable for a choke coil or the like.
【図１】 （ａ）は、複数の扁平状一次粒子が集合して
なる二次粒子状磁性金属粉を樹脂製品に埋め込み、研磨
して得られる断面の模式図である。（ｂ）は、複数の針
状一次粒子が集合してなる二次粒子状磁性金属粉を樹脂
製品に埋め込み、研磨して得られる断面の模式図であ
る。（ｃ）は、複数のひも状一次粒子が絡まってなる二
次粒子状磁性金属粉を樹脂製品に埋め込み、研磨して得
られる断面の模式図である。FIG. 1A is a schematic view of a cross section obtained by embedding and polishing a secondary particulate magnetic metal powder formed by assembling a plurality of flat primary particles in a resin product. (B) is a schematic diagram of a cross section obtained by embedding and polishing a secondary particulate magnetic metal powder composed of a plurality of needle-like primary particles in a resin product. (C) is a schematic diagram of a cross section obtained by embedding and polishing a secondary particulate magnetic metal powder in which a plurality of string-like primary particles are entangled in a resin product.
【図２】 複数の扁平状一次粒子が集合して二次粒子を
形成している磁性金属粉の電子顕微鏡写真（倍率４００
倍）である。FIG. 2 is an electron micrograph (magnification: 400) of a magnetic metal powder in which a plurality of flat primary particles are aggregated to form secondary particles.
Times).
【図３】 複数のひも状一次粒子が絡みあって、スポン
ジ状二次粒子を形成している磁性金属粉の電子顕微鏡写
真（倍率５００倍）である。FIG. 3 is an electron micrograph (500 × magnification) of magnetic metal powder in which a plurality of string-like primary particles are entangled to form sponge-like secondary particles.
【図４】 一次粒子同士の結着を説明する模式図であ
る。FIG. 4 is a schematic diagram illustrating the binding between primary particles.
───────────────────────────────────────────────────── フロントページの続き Ｆターム(参考） 4K017 AA03 BA06 CA03 DA04 EA04 EA06 EB01 EH18 FB05 4K018 BA15 BB01 BB04 BC08 BC11 BD01 KA44 5E041 AA11 AA19 CA02 HB05 HB08 NN06 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4K017 AA03 BA06 CA03 DA04 EA04 EA06 EB01 EH18 FB05 4K018 BA15 BB01 BB04 BC08 BC11 BD01 KA44 5E041 AA11 AA19 CA02 HB05 HB08 NN06
Claims (6)
る鉄基磁性金属粉において、二次粒子が、（１）複数の
扁平状一次粒子の集合体、（２）複数の針状一次粒子の
集合体、または（３）複数のひも状一次粒子が絡まって
スポンジ状に形成された集合体であることを特徴とする
高透磁率の圧粉磁芯用鉄基磁性金属粉。An iron-based magnetic metal powder comprising secondary particles in which a plurality of primary particles are aggregated, wherein the secondary particles are (1) an aggregate of a plurality of flat primary particles, and (2) a plurality of acicular primary particles. An iron-based magnetic metal powder for a dust core having a high magnetic permeability, wherein the iron-based magnetic powder is an aggregate of particles or (3) an aggregate in which a plurality of string-like primary particles are entangled to form a sponge.
ｍであることを特徴とする請求項１に記載の高透磁率の
圧粉磁芯用鉄基磁性金属粉。2. The secondary particles have an average particle size of 40 to 100 μm.
2. The iron-based magnetic metal powder for a dust core having a high magnetic permeability according to claim 1, wherein m is m.
μｍ，平均アスペクト比が２〜１００であることを特徴
とする請求項１または２に記載の高透磁率の圧粉磁芯用
鉄基磁性金属粉。3. An average minor axis length of a cross section of the primary particles is 1 to 5.
The iron-based magnetic metal powder for a dust core having a high magnetic permeability according to claim 1 or 2, wherein the average magnetic aspect ratio is 2 to 100 µm.
還元して得たものであることを特徴とする請求項１〜３
のいずれかに記載の高透磁率の圧粉磁芯用鉄基磁性金属
粉。4. The sponge-like iron-based magnetic metal powder is obtained by reducing iron oxide.
The iron-based magnetic metal powder for a dust core having a high magnetic permeability according to any one of the above.
扁平加工することによって得たものであることを特徴と
する請求項１〜３のいずれかに記載の高透磁率の圧粉磁
芯用鉄基磁性金属粉。5. The dust core having a high magnetic permeability according to claim 1, wherein said flat primary particles are obtained by flattening atomized iron powder. For iron-based magnetic metal powder.
することによって得たものであることを特徴とする請求
項１〜３のいずれかに記載の高透磁率の圧粉磁芯用鉄基
磁性金属粉。6. The dust core having a high magnetic permeability according to claim 1, wherein the needle-like primary particles are obtained by cutting a smelted steel material. For iron-based magnetic metal powder.
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|---|---|---|---|
| JP28427599A JP2001107104A (en) | 1999-10-05 | 1999-10-05 | High permeability iron-base magnetic metal powder for powder magnetic core |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28427599A JP2001107104A (en) | 1999-10-05 | 1999-10-05 | High permeability iron-base magnetic metal powder for powder magnetic core |
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| Publication Number | Publication Date |
|---|---|
| JP2001107104A true JP2001107104A (en) | 2001-04-17 |
Family
ID=17676432
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| JP2006049625A (en) * | 2004-08-05 | 2006-02-16 | Denso Corp | Manufacturing method of soft magnetic material |
| JP4548035B2 (en) * | 2004-08-05 | 2010-09-22 | 株式会社デンソー | Method for producing soft magnetic material |
| CN102049516A (en) * | 2009-10-30 | 2011-05-11 | Tdk株式会社 | Surface-treated reduced iron powder and method for manufacturing the same, and powder magnetic core |
| JP2011179077A (en) * | 2010-03-02 | 2011-09-15 | Seiko Epson Corp | Granulated powder, sintered compact, and metallic filter |
| JP2011187568A (en) * | 2010-03-05 | 2011-09-22 | Toshiba Corp | Nanoparticle composite material, antenna device using the same, and electromagnetic wave absorber |
| JP2011216745A (en) * | 2010-03-31 | 2011-10-27 | Hitachi Powdered Metals Co Ltd | Dust core and method of manufacturing the same |
| JP2014131054A (en) * | 2011-08-31 | 2014-07-10 | Toshiba Corp | Magnetic material |
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