【０００１】
【産業上の利用分野】
この発明は、モータ、アクチュエータ、磁気センサなどの製造に使用される
高密度、高抵抗および高磁束密度を有する複合軟磁性焼結材の製造方法に関するものである。
【０００２】
【従来の技術】
一般に、モータ、アクチュエータ、磁気センサなどの磁心にはＦｅ−Ｃｏ系鉄基軟磁性合金粉末を燒結して得られた軟磁性焼結材料が用いられることは知られており、さらに、この軟磁性焼結材料の一つとしてフェライトが知られている。前記Ｆｅ−Ｃｏ系鉄基軟磁性合金粉末などを燒結して得られた軟磁性焼結材料は、飽和磁束密度が高いが、高周波特性が悪く、一方、フェライトなど鉄酸化物粉末を焼結して得られた酸化物軟磁性焼結材料は、抵抗が高いために高周波特性に優れ、初透磁率が比較的高いが、飽和磁束密度が低い欠点があり、これらを改善するために、Ｆｅ−Ｃｏ系鉄基軟磁性合金粉末の表面にフェライト膜を被覆してなるフェライト膜被覆Ｆｅ−Ｃｏ系鉄基軟磁性合金粉末が提案されており、このフェライト膜被覆鉄軟磁性粉末を焼結して得られた焼結材料は高抵抗を有し、飽和磁束密度および高周波特性に共に優れると言われている。
【０００３】
このフェライト膜被覆Ｆｅ−Ｃｏ系鉄基軟磁性合金粉末を製造するための方法として、Ｆｅ−Ｃｏ系鉄基軟磁性合金粉末の表面に湿式フェライトメッキによりフェライト膜を形成する方法（特許文献１または２参照）、
Ｆｅ−Ｃｏ系鉄基軟磁性合金粉末およびフェライト粉末をメカノフュージョン装置に入れて高速回転させることによりＦｅ−Ｃｏ系鉄基軟磁性合金粉末の表面にフェライト粉末を埋め込み、それによってＦｅ−Ｃｏ系鉄基軟磁性合金粉末の表面にフェライト膜を形成する方法（特許文献３参照）などが知られており、これらフェライト膜被覆Ｆｅ−Ｃｏ系鉄基軟磁性合金粉末を圧粉、成形し、焼結することにより複合軟磁性焼結材を製造する方法も知られている。
【０００４】
【特許文献１】
特開昭５６−３８４０２号公報
【特許文献２】
特開平１１−１７０２号公報
【特許文献３】
特開平４−２２６００３号公報
【０００５】
【発明が解決しようとする課題】
しかし、前記Ｆｅ−Ｃｏ系鉄基軟磁性合金粉末の表面にフェライト膜を被覆してなるフェライト膜被覆Ｆｅ−Ｃｏ系鉄基軟磁性合金粉末を原料粉末とし、これを圧粉、成形、焼結して複合軟磁性焼結材を製造すると、焼結時に、芯部のＦｅ−Ｃｏ系鉄基軟磁性合金粉末とフェライト間でフェライトの還元反応が起こり、フェライト（Ｆｅ３Ｏ４）層はウスタイト（ＦｅＯ）層に変化するなどして酸素不足のフェライト膜がＦｅ−Ｃｏ系鉄基軟磁性合金粉末表面に形成され、この酸素不足のフェライト膜は固有抵抗値が低く、したがって得られた複合軟磁性焼結材の抵抗値が十分なものではない。
【０００６】
【課題を解決するための手段】
そこで、本発明者らは、かかる課題を解決すべく研究を行った結果、
Ｆｅ−Ｃｏ系鉄基軟磁性合金粉末の表面に電解メッキまたは無電解メッキにより第１層としてＮｉ層が形成し、このＮｉ層が形成されたＦｅ−Ｃｏ系鉄基軟磁性合金粉末の表面に第２層としてフェライト層を被覆して積層膜被覆Ｆｅ−Ｃｏ系鉄基軟磁性合金粉末を作製し、この積層膜被覆Ｆｅ−Ｃｏ系鉄基軟磁性合金粉末を原料粉末として圧粉、成形した後、非酸化雰囲気中または酸素分圧制御雰囲気中、温度：７００〜１１００℃で焼結すると、Ｆｅ−Ｃｏ系鉄基軟磁性合金粉末とフェライト層の間にＮｉ層が介在することによりフェライトの還元が防止され、したがって酸素不足のフェライト膜が形成されないために高抵抗を有する複合軟磁性焼結材が得られ、さらにこの積層膜被覆Ｆｅ−Ｃｏ系鉄基軟磁性合金粉末を原料粉末として作製した複合軟磁性焼結材は密度が一層向上する、という研究結果が得られたのである。
【０００７】
この発明は、かかる研究結果に基づいてなされたものであって、
Ｆｅ−Ｃｏ系鉄基軟磁性合金粉末の表面に、第１層としてＮｉ層、第２層としてフェライト層を被覆してなる積層膜被覆Ｆｅ−Ｃｏ系鉄基軟磁性合金粉末を作製し、この積層膜被覆Ｆｅ−Ｃｏ系鉄基軟磁性合金粉末を圧粉、成形した後、非酸化雰囲気中または酸素分圧制御雰囲気中、温度：７００〜１１００℃で焼結する高密度および高抵抗を有する複合軟磁性焼結材の製造方法、に特徴を有するものである。
【０００８】
この発明の高密度および高抵抗を有する複合軟磁性焼結材の製造方法をさらに一層具体的に説明する。
この発明の高密度および高抵抗を有する複合軟磁性焼結材の製造方法において使用するＦｅ−Ｃｏ系鉄基軟磁性合金粉末は、従来から一般に知られているＣｏ：２５〜６０質量％を含有し、残部がＦｅおよび不可避不純物からなる組成、またはＣｏ：２５〜６０質量％、Ｖ：０．５〜５質量％を含有し、残部がＦｅおよび不可避不純物からなる組成を有するＦｅ−Ｃｏ系軟磁性合金粉末を使用することが好ましい。しかし、この発明の高密度および高透磁性を有する複合軟磁性焼結材の製造方法において使用する前記Ｆｅ−Ｃｏ系軟磁性合金粉末は、前記成分組成を有するＦｅ−Ｃｏ系軟磁性合金粉末に限定されるものではなく、その他のＦｅ−Ｃｏ系軟磁性合金粉末を使用することができる。そして、これらＦｅ−Ｃｏ系鉄基軟磁性合金粉末は平均粒径：５〜１５０μｍの範囲内にあるＦｅ−Ｃｏ系鉄基軟磁性合金粉末を使用することが好ましい。その理由は、平均粒径が５μｍよりも小さすぎると、粉末の圧縮性が低下し、Ｆｅ−Ｃｏ系鉄基軟磁性合金の体積割合が低くなるために飽和磁束密度の値が低下するので好ましくなく、一方、平均粒径が１５０μｍより大きすぎると、Ｆｅ−Ｃｏ系鉄基軟磁性合金粉末内部の渦電流が増大して高周波における透磁率が低下するので好ましくないことによるものである。
【０００９】
これらＦｅ−Ｃｏ系鉄基軟磁性合金粉末の表面に電解メッキまたは無電解メッキにより第１層として厚さ：２〜５μｍのＮｉ層を被覆し、このＮｉ層の上に第２層としてのフェライト層を被覆することによりＮｉ層およびフェライト層で構成された積層膜を形成してなる積層膜被覆Ｆｅ−Ｃｏ系鉄基軟磁性合金粉末を作製することができる。このＮｉ膜の上に形成するフェライト層は、化学メッキ法、高速衝撃撹拌被覆法またはバインダー被覆法など一般に知られている方法で作製することができる。
【００１０】
このようにして得られた積層膜被覆Ｆｅ−Ｃｏ系鉄基軟磁性合金粉末を圧粉、成形した後、非酸化雰囲気中または酸素分圧制御雰囲気中、温度：７００〜１１００℃（好ましくは、７００〜９００℃）で焼結すると高密度および高抵抗を有する複合軟磁性焼結材が得られる。かかる温度で焼結すると、ＮｉはＦｅ−Ｃｏ系鉄基軟磁性合金粉末に拡散してＦｅ−Ｃｏ−Ｎｉ合金を形成し、軟磁性合金としての特性を向上させ、さらにＮｉ層の介在によりＦｅ−Ｃｏ系鉄基合金とフェライトの還元反応を防止し、磁気特性を向上させ、高密度および高抵抗を有する複合軟磁性焼結材が得られる。この場合、焼結温度が７００℃未満ではＮｉが芯材であるＦｅ−Ｃｏ系軟磁性合金粉末に十分拡散されずにＮｉ層として残存するので磁気特性が低下するので好ましくなく、一方、１１００℃を越える温度で焼結すると、Ｆｅ−Ｃｏ相とフェライト相の反応により比抵抗の低下が起こるので好ましくない。また、この発明において非酸化雰囲気とは水素ガス、Ｃｏガスなどの還元ガス雰囲気、またはＡｒガスもしくは窒素ガスなどの不活性ガス雰囲気を言い、また酸素分圧制御雰囲気とは窒素がスと酸素ガスとの混合ガスあるいは炭酸ガス雰囲気を言う。
【００１１】
【発明の実施の形態】
原料粉末として、いずれも平均粒径：７０μｍを有するＣｏ：３０質量％を含有し、残部がＦｅおよび不可避不純物からなる組成を有するアトマイズＦｅ−Ｃｏ系軟磁性合金粉末、並びにＣｏ：４９質量％、Ｖ：２質量％を含有し、残部がＦｅおよび不可避不純物からなる組成を有するアトマイズＦｅ−Ｃｏ−Ｖ系軟磁性合金粉末を用意した。
【００１２】
実施例１〜５および比較例１〜２
このＦｅ−Ｃｏ系軟磁性合金粉末に対して電解メッキを施すことによりＦｅ−Ｃｏ系軟磁性合金粉末の表面にＮｉ層を形成し、Ｎｉ被覆Ｆｅ−Ｃｏ系軟磁性合金粉末を作製した。
さらに平均粒径：０．７μｍのフェライト粉末を１〜５質量％分散被覆することによりこのＮｉ被覆Ｆｅ−Ｃｏ系合金粉末のＮｉ層の上にフェライト層を形成して積層膜被覆Ｆｅ−Ｃｏ系合金粉末を作製した。
得られた積層膜被覆Ｆｅ−Ｃｏ系合金粉末を金型に入れ、プレス成形することにより外径：３５ｍｍ、内径：２５ｍｍ、高さ：５ｍｍのリング状圧粉体を成形し、得られたリング状圧粉体を不活性ガス雰囲気中、表１に示される温度で焼結することによりリング状焼結体からなる複合軟磁性焼結材を作製した。このようにして得られた複合軟磁性焼結材の密度および比抵抗を測定してその結果を表１に示した。さらに複合軟磁性焼結材に巻き線を施し、ＢＨトレーサにて磁束密度を測定し、その結果を表１に示した。
【００１３】
従来例１
高速衝撃撹拌法により作製した市販のフェライト膜被覆純Ｆｅ−Ｃｏ系鉄基軟磁性合金粉末を用意し、この粉末を用いて実施例１と同様にしてリング焼結体からなる複合軟磁性焼結材を得た。このようにして得られた複合軟磁性焼結材の密度および比抵抗を測定してその結果を表１に示した。さらに複合軟磁性焼結材に巻き線を施し、ＢＨトレーサにて磁束密度を測定し、その結果を表１に示した。
【００１４】
【表１】
【００１５】
表１に示される結果から、実施例１〜５で作製した複合軟磁性焼結材は、従来例１で製造した複合軟磁性焼結材と比べて密度及び比抵抗に優れた特性を示すことが分かる。しかし、比較例１〜２で作製した複合軟磁性焼結材は密度、比抵抗および磁束密度のうちの少なくともいずれか一つが劣るので好ましくないことが分かる。
【００１６】
実施例６〜１０および比較例３〜４
先に用意したアトマイズＦｅ−Ｃｏ−Ｖ系鉄基軟磁性合金粉末に対して電解メッキを施すことによりＦｅ−Ｃｏ−Ｖ系軟磁性合金粉末の表面にＮｉ層を形成し、Ｎｉ被覆Ｆｅ−Ｃｏ−Ｖ系軟磁性合金粉末を作製した。
さらに平均粒径：０．７μｍのフェライト粉末を１〜５質量％分散被覆することによりこのＮｉ被覆Ｆｅ−Ｃｏ−Ｖ系合金粉末のＮｉ層の上にフェライト層を形成して積層膜被覆Ｆｅ−Ｃｏ−Ｖ系合金粉末を作製した。
得られた積層膜被覆Ｆｅ−Ｃｏ−Ｖ系合金粉末を金型に入れ、プレス成形により外径：３５ｍｍ、内径：２５ｍｍ、高さ：５ｍｍのリング状圧粉体を成形し、得られたリング状圧粉体を不活性ガス雰囲気中、表１に示される温度で焼結することによりリング状焼結体からなる複合軟磁性焼結材を作製した。このようにして得られた複合軟磁性焼結材の密度および比抵抗を測定してその結果を表２に示した。さらに複合軟磁性焼結材に巻き線を施し、ＢＨトレーサにて磁束密度を測定し、その結果を表２に示した。
【００１７】
従来例２
高速衝撃撹拌法により作製した市販のフェライト膜被覆純Ｆｅ−Ｃｏ−Ｖ系鉄基軟磁性合金粉末を用意し、この粉末を用いて実施例６と同様にしてリング焼結体からなる複合軟磁性焼結材を得た。このようにして得られた複合軟磁性焼結材の密度および比抵抗を測定してその結果を表２に示した。さらに複合軟磁性焼結材に巻き線を施し、ＢＨトレーサにて磁束密度を測定し、その結果を表２に示した。
【００１８】
【表２】
【００１９】
表２に示される結果から、実施例６〜１０で作製した複合軟磁性焼結材は、従来例２で作製した複合軟磁性焼結材と比べて密度及び比抵抗に優れた特性を示すことが分かる。しかし、比較例３〜４で作製した複合軟磁性焼結材は密度、比抵抗および磁束密度の少なくともいずれか一つが劣るので好ましくないことが分かる。
【００２０】
【発明の効果】
この発明によると、簡単な方法により高密度、高抵抗および高磁束密度を有する複合軟磁性焼結材を提供することができ、電気および電子産業において優れた効果をもたらすものである。[0001]
[Industrial applications]
The present invention relates to a method for manufacturing a composite soft magnetic sintered material having a high density, a high resistance and a high magnetic flux density used for manufacturing a motor, an actuator, a magnetic sensor and the like.
[0002]
[Prior art]
In general, it is known that a soft magnetic sintered material obtained by sintering Fe-Co based iron-based soft magnetic alloy powder is used for a magnetic core of a motor, an actuator, a magnetic sensor, and the like. Ferrite is known as one of the sintered materials. The soft magnetic sintered material obtained by sintering the Fe-Co-based iron-based soft magnetic alloy powder or the like has a high saturation magnetic flux density, but has poor high frequency characteristics. The resulting oxide soft magnetic sintered material has excellent high frequency characteristics due to high resistance and relatively high initial permeability, but has a drawback of low saturation magnetic flux density. A ferrite film-coated Fe-Co-based iron-based soft magnetic alloy powder in which a ferrite film is coated on the surface of a Co-based iron-based soft magnetic alloy powder has been proposed. It is said that the obtained sintered material has high resistance and is excellent in both saturation magnetic flux density and high frequency characteristics.
[0003]
As a method for producing the ferrite film-coated Fe-Co-based iron-based soft magnetic alloy powder, a method of forming a ferrite film on the surface of the Fe-Co-based iron-based soft magnetic alloy powder by wet ferrite plating (Patent Document 1 or 2),
The ferrite powder is embedded in the surface of the Fe-Co-based iron-based soft magnetic alloy powder by putting the Fe-Co-based iron-based soft-magnetic alloy powder and the ferrite powder in a mechanofusion device and rotating at a high speed, whereby the Fe-Co-based iron A method of forming a ferrite film on the surface of a base soft magnetic alloy powder (see Patent Document 3) and the like are known. These ferrite film-coated Fe—Co iron-based soft magnetic alloy powders are compacted, molded, and sintered. There is also known a method of producing a composite soft magnetic sintered material.
[0004]
[Patent Document 1]
JP-A-56-38402 [Patent Document 2]
JP-A-11-1702 [Patent Document 3]
JP-A-4-226003
[Problems to be solved by the invention]
However, a ferrite film-coated Fe-Co-based iron-based soft magnetic alloy powder obtained by coating a surface of the Fe-Co-based iron-based soft magnetic alloy powder with a ferrite film is used as a raw material powder, which is compacted, molded, and sintered. When the composite soft magnetic sintered material is manufactured by the above method, a reduction reaction of ferrite occurs between the Fe—Co-based iron-based soft magnetic alloy powder of the core and the ferrite during sintering, and the ferrite (Fe 3 O 4 ) layer becomes wustite. An oxygen-deficient ferrite film is formed on the surface of the Fe—Co-based iron-based soft magnetic alloy powder by changing to a (FeO) layer, and the oxygen-deficient ferrite film has a low specific resistance value. The resistance value of the magnetic sintered material is not sufficient.
[0006]
[Means for Solving the Problems]
Therefore, the present inventors have conducted research to solve this problem,
A Ni layer is formed as a first layer on the surface of the Fe-Co-based iron-based soft magnetic alloy powder by electrolytic plating or electroless plating, and the Ni-layer is formed on the surface of the Fe-Co-based iron-based soft magnetic alloy powder. A ferrite layer was coated as a second layer to produce a laminated film-coated Fe-Co-based iron-based soft magnetic alloy powder, and the laminated film-coated Fe-Co-based iron-based soft magnetic alloy powder was pressed and molded as a raw material powder. Thereafter, when sintering is performed in a non-oxidizing atmosphere or an oxygen partial pressure control atmosphere at a temperature of 700 to 1100 ° C., the Ni-layer intervenes between the Fe—Co-based iron-based soft magnetic alloy powder and the ferrite layer. Since reduction is prevented, and thus an oxygen-deficient ferrite film is not formed, a composite soft magnetic sintered material having high resistance can be obtained. Further, this laminated film-coated Fe-Co-based iron-based soft magnetic alloy powder is used as a raw material powder. Composite soft magnetic sintered material is the density is further improved, finding that were obtained.
[0007]
The present invention has been made based on such research results,
On the surface of the Fe-Co-based iron-based soft magnetic alloy powder, a Ni-layer as a first layer and a ferrite layer as a second layer are coated to produce a laminated film-coated Fe-Co-based iron-based soft magnetic alloy powder. After laminating and molding the laminated film-coated Fe—Co-based iron-based soft magnetic alloy powder, it is sintered at a temperature of 700 to 1100 ° C. in a non-oxidizing atmosphere or an oxygen partial pressure control atmosphere. The method is characterized by a method for producing a composite soft magnetic sintered material.
[0008]
The method for producing a composite soft magnetic sintered material having high density and high resistance according to the present invention will be described more specifically.
The Fe—Co-based iron-based soft magnetic alloy powder used in the method for producing a composite soft magnetic sintered material having a high density and a high resistance according to the present invention contains 25 to 60% by mass of Co, which is conventionally generally known. And a balance composed of Fe and unavoidable impurities, or a Fe-Co-based soft alloy containing Co: 25 to 60% by mass and V: 0.5 to 5% by mass and a balance composed of Fe and unavoidable impurities. It is preferable to use a magnetic alloy powder. However, the Fe-Co-based soft magnetic alloy powder used in the method for producing a composite soft magnetic sintered material having high density and high magnetic permeability of the present invention is different from the Fe-Co-based soft magnetic alloy powder having the component composition described above. It is not limited, and other Fe—Co-based soft magnetic alloy powders can be used. It is preferable that the Fe-Co-based iron-based soft magnetic alloy powder has an average particle diameter of 5 to 150 µm. The reason is that when the average particle size is smaller than 5 μm, the compressibility of the powder is reduced, and the volume ratio of the Fe-Co-based iron-based soft magnetic alloy is reduced, so that the value of the saturation magnetic flux density is reduced. On the other hand, if the average particle size is too large, the eddy current inside the Fe-Co-based iron-based soft magnetic alloy powder increases and the magnetic permeability at high frequencies decreases, which is not preferable.
[0009]
The surface of these Fe—Co-based iron-based soft magnetic alloy powders is coated with a Ni layer having a thickness of 2 to 5 μm as a first layer by electrolytic plating or electroless plating, and a ferrite as a second layer is formed on the Ni layer. By coating the layers, a laminated film-coated Fe—Co-based iron-based soft magnetic alloy powder formed by forming a laminated film composed of a Ni layer and a ferrite layer can be produced. The ferrite layer formed on the Ni film can be manufactured by a generally known method such as a chemical plating method, a high-speed impact stirring coating method or a binder coating method.
[0010]
After the thus-obtained laminated film-coated Fe—Co-based iron-based soft magnetic alloy powder is compacted and formed, the temperature is 700 to 1100 ° C. (preferably, in a non-oxidizing atmosphere or an oxygen partial pressure controlling atmosphere). (700-900 ° C.), a composite soft magnetic sintered material having high density and high resistance is obtained. When sintering at such a temperature, Ni diffuses into the Fe-Co-based iron-based soft magnetic alloy powder to form an Fe-Co-Ni alloy, thereby improving the characteristics as a soft magnetic alloy, and further, by interposing a Ni layer, -A composite soft magnetic sintered material having a high density and a high resistance can be obtained by preventing a reduction reaction between a Co-based iron-based alloy and ferrite, improving magnetic properties, and having a high density. In this case, if the sintering temperature is less than 700 ° C., Ni is not sufficiently diffused into the core material, ie, the Fe—Co-based soft magnetic alloy powder, and remains as a Ni layer. If the sintering is performed at a temperature higher than the above, the specific resistance is lowered due to the reaction between the Fe-Co phase and the ferrite phase, which is not preferable. In the present invention, the non-oxidizing atmosphere refers to a reducing gas atmosphere such as a hydrogen gas or a Co gas, or an inert gas atmosphere such as an Ar gas or a nitrogen gas, and the oxygen partial pressure control atmosphere refers to a nitrogen gas and an oxygen gas. Gas atmosphere or carbon dioxide gas atmosphere.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Atomized Fe—Co-based soft magnetic alloy powder containing 30% by mass of Co having an average particle diameter of 70 μm and the balance of Fe and unavoidable impurities, and 49% by mass of Co as raw material powders; V: An atomized Fe—Co—V soft magnetic alloy powder containing 2% by mass and having a balance of Fe and inevitable impurities was prepared.
[0012]
Examples 1 to 5 and Comparative Examples 1 and 2
By subjecting the Fe-Co-based soft magnetic alloy powder to electrolytic plating, a Ni layer was formed on the surface of the Fe-Co-based soft magnetic alloy powder to prepare a Ni-coated Fe-Co-based soft magnetic alloy powder.
Further, a ferrite layer having an average particle size of 0.7 μm is dispersed and coated in an amount of 1 to 5% by mass to form a ferrite layer on the Ni layer of the Ni-coated Fe—Co alloy powder, thereby forming a laminated film-coated Fe—Co alloy. An alloy powder was produced.
The obtained laminated film-coated Fe—Co-based alloy powder was put into a mold and press-molded to form a ring-shaped green compact having an outer diameter of 35 mm, an inner diameter of 25 mm, and a height of 5 mm, and the obtained ring was formed. By sintering the green compact in an inert gas atmosphere at the temperature shown in Table 1, a composite soft magnetic sintered material composed of a ring-shaped sintered body was produced. The density and specific resistance of the composite soft magnetic sintered material thus obtained were measured, and the results are shown in Table 1. Further, the composite soft magnetic sintered material was wound, and the magnetic flux density was measured with a BH tracer. The results are shown in Table 1.
[0013]
Conventional example 1
A commercially available ferrite film-coated pure Fe-Co iron-based soft magnetic alloy powder prepared by a high-speed impact stirring method was prepared, and a composite soft magnetic sinter comprising a ring sintered body was prepared using this powder in the same manner as in Example 1. Wood was obtained. The density and specific resistance of the composite soft magnetic sintered material thus obtained were measured, and the results are shown in Table 1. Further, the composite soft magnetic sintered material was wound, and the magnetic flux density was measured with a BH tracer. The results are shown in Table 1.
[0014]
[Table 1]
[0015]
From the results shown in Table 1, the composite soft magnetic sintered materials produced in Examples 1 to 5 show characteristics superior in density and specific resistance as compared with the composite soft magnetic sintered material produced in Conventional Example 1. I understand. However, it can be seen that the composite soft magnetic sintered materials produced in Comparative Examples 1 and 2 are not preferable because at least one of density, specific resistance and magnetic flux density is inferior.
[0016]
Examples 6 to 10 and Comparative Examples 3 to 4
An Ni layer is formed on the surface of the Fe-Co-V-based soft magnetic alloy powder by subjecting the previously prepared atomized Fe-Co-V-based iron-based soft magnetic alloy powder to electrolytic plating, and the Ni-coated Fe-Co A -V soft magnetic alloy powder was produced.
Further, a ferrite powder having an average particle size of 0.7 μm is dispersed and coated in an amount of 1 to 5% by mass to form a ferrite layer on the Ni layer of the Ni-coated Fe—Co—V-based alloy powder so that the laminated film-coated Fe— A Co-V alloy powder was produced.
The obtained laminated film-coated Fe—Co—V-based alloy powder is put into a mold, and a ring-shaped green compact having an outer diameter of 35 mm, an inner diameter of 25 mm, and a height of 5 mm is formed by press molding, and the obtained ring is formed. By sintering the green compact in an inert gas atmosphere at the temperature shown in Table 1, a composite soft magnetic sintered material composed of a ring-shaped sintered body was produced. The density and specific resistance of the composite soft magnetic sintered material thus obtained were measured, and the results are shown in Table 2. Further, the composite soft magnetic sintered material was wound, and the magnetic flux density was measured with a BH tracer. The results are shown in Table 2.
[0017]
Conventional example 2
A commercially available ferrite film-coated pure Fe-Co-V-based iron-based soft magnetic alloy powder prepared by a high-speed impact stirring method was prepared, and a composite soft magnetic material comprising a ring sintered body was prepared using this powder in the same manner as in Example 6. A sintered material was obtained. The density and specific resistance of the composite soft magnetic sintered material thus obtained were measured, and the results are shown in Table 2. Further, the composite soft magnetic sintered material was wound, and the magnetic flux density was measured with a BH tracer. The results are shown in Table 2.
[0018]
[Table 2]
[0019]
From the results shown in Table 2, the composite soft magnetic sintered materials manufactured in Examples 6 to 10 show characteristics superior in density and specific resistance as compared with the composite soft magnetic sintered material manufactured in Conventional Example 2. I understand. However, it can be seen that the composite soft magnetic sintered materials produced in Comparative Examples 3 and 4 are not preferable because at least one of the density, the specific resistance and the magnetic flux density is inferior.
[0020]
【The invention's effect】
According to the present invention, it is possible to provide a composite soft magnetic sintered material having a high density, a high resistance and a high magnetic flux density by a simple method, and to provide excellent effects in the electric and electronic industries.
