JP2013187480A - Powder for dust magnetic core - Google Patents
Powder for dust magnetic core Download PDFInfo
- Publication number
- JP2013187480A JP2013187480A JP2012053335A JP2012053335A JP2013187480A JP 2013187480 A JP2013187480 A JP 2013187480A JP 2012053335 A JP2012053335 A JP 2012053335A JP 2012053335 A JP2012053335 A JP 2012053335A JP 2013187480 A JP2013187480 A JP 2013187480A
- Authority
- JP
- Japan
- Prior art keywords
- powder
- less
- molding
- iron
- magnetic
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Abstract
Description
本発明は、高い密度を有し、かつ低鉄損である圧粉磁芯を製造するための圧粉磁芯用粉末に関するものである。 The present invention relates to a dust core powder for producing a dust core having a high density and low iron loss.
モーターやトランスなどに用いられる磁芯には、磁束密度が高くて鉄損が低いという特性が要求される。
従来、モーターなどの磁芯には、電磁鋼板を積層したものが用いられてきた。しかしながら、近年、モーター用磁芯材料として、圧粉磁芯が注目されている。
Magnetic cores used in motors and transformers are required to have high magnetic flux density and low iron loss.
Conventionally, laminated magnetic steel sheets have been used for magnetic cores such as motors. However, in recent years, a dust core has attracted attention as a magnetic core material for motors.
圧粉磁芯の最大の特徴は、三次元的な磁気回路が形成可能な点である。電磁鋼板は積層することによって磁芯を成形する為、形状の自由度に限界があるが、圧粉磁芯は絶縁被覆された軟磁性粒子をプレスして成形する為、金型を変更することで、電磁鋼板を上回る形状の自由度を得ることができる。 The biggest feature of the dust core is that a three-dimensional magnetic circuit can be formed. Magnetic steel sheets form a magnetic core by laminating, so there is a limit to the degree of freedom of shape, but dust cores are formed by pressing soft magnetic particles with insulation coating, so changing the mold Thus, the degree of freedom of the shape exceeding that of the electromagnetic steel sheet can be obtained.
また、プレス成形は、鋼板を積層する工程に比べて、必要な工程が短く、かつコストが安い為、ベースとなる粉末の安さも相まって、優れたコストパフォーマンスを発揮する。 In addition, press forming has a short cost and low cost compared to the process of laminating steel sheets, and exhibits excellent cost performance in combination with the low cost of the base powder.
ここに、電磁鋼板は、鋼板表面が絶縁されたものを積層する為、鋼板の表面方向と表面に垂直な方向とでは、それぞれ磁気特性が異なるだけでなく、表面に垂直な方向の磁気特性が悪いという欠点を有しているものの、圧粉磁芯は粒子一つ一つが絶縁被膜に覆われている為、あらゆる方向に対して磁気特性が均一となり、上述したように、三次元的な磁気回路を構成するのに適している。 Here, the magnetic steel sheets are laminated with the steel sheet surfaces insulated, so that not only the magnetic characteristics differ between the surface direction of the steel sheet and the direction perpendicular to the surface, but also the magnetic characteristics in the direction perpendicular to the surface. Although it has the disadvantage of being bad, the dust core has a uniform magnetic property in all directions because each particle is covered with an insulating coating. Suitable for constructing a circuit.
上述したように、圧粉磁芯は、三次元磁気回路を設計する上で不可欠な素材であると同時にコストパフォーマンスに優れることから、近年要求されている、モーターの小型化、レアアースフリー化、低コスト化などを実現する為に、圧粉磁芯を利用した三次元磁気回路を有するモーターの研究開発が盛んに行われている。 As described above, the dust core is an indispensable material for designing a three-dimensional magnetic circuit, and at the same time has excellent cost performance. In order to realize cost reduction and the like, research and development of a motor having a three-dimensional magnetic circuit using a dust core has been actively conducted.
このような粉末冶金技術により高性能の磁性部品を製造する場合、高密度の部品が得られる様に一定の成形圧力で加圧成形したとき、より高密度となる高圧縮性と、成形後の優れた損失特性（低ヒステリシス損、低渦電流損）が要求される。圧縮性の改善には、粉末の金型への充填率を高めること及び塑性変形し易くすることが、鉄損の低減のためには、成形後の結晶粒を粗大化させること、粉末平均粒子径を適切（モーター用途を想定した場合、75〜150μｍ）に調整すること、成形後も粒子間の絶縁性を保持することが重要である。
また、特に、モーターの小型化に伴う高速回転化により、中高周波（800Hz〜３kHz）における鉄損の低減が重要になってきている。
When manufacturing high-performance magnetic parts by such powder metallurgy technology, high-compressibility that becomes higher density when molded under pressure at a constant molding pressure so that high-density parts can be obtained, and after molding Excellent loss characteristics (low hysteresis loss, low eddy current loss) are required. In order to improve compressibility, it is necessary to increase the filling rate of the powder into the mold and facilitate plastic deformation. In order to reduce iron loss, the crystal grains after forming are coarsened, and the powder average particle It is important to adjust the diameter appropriately (75 to 150 μm when a motor application is assumed) and to maintain the insulation between the particles even after molding.
In particular, reduction in iron loss at medium and high frequencies (800 Hz to 3 kHz) has become important due to high-speed rotation accompanying miniaturization of motors.
これらの現状に対し、例えば、特許文献１では、粉末の保磁力、つまりはヒステリシス損を低減するために、75μｍ以下の微粉を20％以下とし、粒子内の結晶粒径を粗大化させる技術が開示されている。この技術により、粉末の保磁力は減少し、付帯的な効果ではあるが粒子が軟化して圧締性も改善する。 In order to reduce the coercive force of the powder, that is, the hysteresis loss, for example, Patent Document 1 discloses a technique for reducing the fine particle size of 75 μm or less to 20% or less and increasing the crystal grain size in the particle. It is disclosed. With this technique, the coercive force of the powder is reduced, and although it is an incidental effect, the particles are softened and the pressability is improved.
また、特許文献２および３では、粒度分布に２つのピークを持たせることにより金型への充填率を高める技術が開示されている。 Patent Documents 2 and 3 disclose a technique for increasing the filling rate of a mold by providing two peaks in the particle size distribution.
しかしながら、特許文献１に記載の技術では、粒子の金型への充填率を上げる試みが全くなされていない。粒子の圧縮性を改善するためには鉄粉を軟化させると同時に金型への充填率を上げ、粒子の塑性変形による硬化を最小限に抑えることが重要である。また、金型への粉末の充填率が低く、塑性変形量が増大した場合、粒子の硬化だけでなく成形体内部の結晶粒の微細化を招き、ヒステリシス損が増加する。圧粉磁芯として用いる場合に重要なのは成形後の保磁力の低減であり、粉末の状態でいくら保磁力を下げたところで、成形によって粉末が大きく塑性変形してしまっては粉末の保磁力を低減した効果は半減してしまう。粉末の金型への充填率を上げるためには、ある程度の微粉が必要であり、75μｍ以下の微粉を20％以下としてしまっては、かえってヒステリシス損の増加を招く。
以上の点で、特許文献１における鉄損低減、圧縮性改善の試みは、未だ十分なものとは言えない。
However, in the technique described in Patent Document 1, no attempt has been made to increase the filling rate of particles into the mold. In order to improve the compressibility of the particles, it is important to soften the iron powder and at the same time increase the filling rate in the mold to minimize hardening due to plastic deformation of the particles. Further, when the filling rate of the powder into the mold is low and the amount of plastic deformation increases, not only the particles are cured but also the crystal grains inside the compact are refined, and the hysteresis loss increases. When using it as a dust core, it is important to reduce the coercive force after molding. When the coercive force is lowered in the powder state, the coercive force of the powder is reduced if the powder is greatly plastically deformed by molding. The effect will be halved. In order to increase the filling rate of the powder into the mold, a certain amount of fine powder is required. If the fine powder of 75 μm or less is made 20% or less, the hysteresis loss is increased instead.
From the above points, the attempt of reducing iron loss and improving compressibility in Patent Document 1 is still not sufficient.
一方、特許文献２に記載の技術では、250〜350μｍという粗大な粒度の粉末を利用する技術であるが、300μｍを超えるような粉末を用いることは、渦電流損低減の観点からは好ましくない。また、特許文献３は、成形加工前の充填率を高めるための技術であって、成形後の鉄損についての検討は不十分である。 On the other hand, the technique described in Patent Document 2 uses a powder having a coarse particle size of 250 to 350 μm, but using a powder exceeding 300 μm is not preferable from the viewpoint of reducing eddy current loss. Moreover, patent document 3 is a technique for raising the filling rate before a shaping | molding process, Comprising: The examination about the iron loss after shaping | molding is inadequate.
従って、上述したような従来の技術では、いずれも圧縮性に優れかつ成形後に低鉄損を呈するような軟磁性粉末を得ることは困難であった。また、いずれに示された技術も、中高周波（800Hz〜３kHz）における鉄損の低減について言及されていない。 Therefore, it has been difficult to obtain a soft magnetic powder that is excellent in compressibility and exhibits low iron loss after molding with the conventional techniques as described above. In addition, none of the techniques shown in this publication mentions reduction of iron loss at medium and high frequencies (800 Hz to 3 kHz).
本発明は、上記の実情に鑑み開発されたものであり、圧縮性に優れ、かつ成形後に低鉄損を呈するような圧粉磁芯用粉末を提供することを目的とする。 The present invention has been developed in view of the above circumstances, and an object thereof is to provide a powder for a dust core that has excellent compressibility and exhibits low iron loss after molding.
発明者らは、前述の課題を解決するために、上記した３つの先行技術を踏まえて、圧粉磁芯用粉末の粒度、硬度に関して検討を重ねてきた。その結果、圧粉磁芯用粉末中の結晶粒を粗大化し、不純物を低減することによって粉末を軟化させること、および鉄損特性に優れる75μｍ以上150μｍ以下の粒度の粉末を最も多くしつつ、150μｍ超300μｍ以下の粗粉末を、75μｍよりも微細な粉末よりも多くなるように粒度を調整することにより、圧縮性に優れると同時に成形後も低鉄損となるような粉末が得られることを見出した。 In order to solve the above-mentioned problems, the inventors have repeatedly studied the particle size and hardness of the powder for powder magnetic core based on the above three prior arts. As a result, it is possible to soften the powder by coarsening the crystal grains in the powder for the dust core and reducing impurities, and to increase the powder with a particle size of 75 μm to 150 μm, which is excellent in iron loss characteristics, while increasing the powder to 150 μm It was found that by adjusting the particle size of coarse powder of ultra 300μm or less to be larger than fine powder of 75μm, a powder with excellent compressibility and low iron loss after molding can be obtained. It was.
本発明は、上記した知見に基づき完成したものであって、本発明の要旨構成は次のとおりである。
１．表面に絶縁被膜をそなえる、粒度が300μｍ以下の圧粉磁芯用粉末であって、
該粉末の粒度を、300μｍ以下150μｍ超、150μｍ以下75μｍ以上、75μｍ未満に３分割した時、150μｍ以下75μｍ以上の質量比率が最も高く、ついで300μｍ以下150μｍ超の質量比率であり、75μｍ未満の質量比率が最も低く、
かつ、該粉末の見掛け密度は3.5g／cm3以上であり、
さらに、任意の40個以上の該粉末の粉末内平均結晶粒径が50μｍ以上であることを特徴とする圧粉磁芯用粉末。
The present invention has been completed based on the above-described findings, and the gist of the present invention is as follows.
1. A powder for a powder magnetic core having an insulating coating on the surface and a particle size of 300 μm or less,
When the particle size of the powder is divided into 300 μm or less and more than 150 μm, 150 μm or less and 75 μm or more and less than 75 μm, the mass ratio of 150 μm or less and 75 μm or more is the highest, then the mass ratio is 300 μm or less and more than 150 μm, and the mass is less than 75 μm The lowest ratio,
And the apparent density of the powder is 3.5 g / cm 3 or more,
Further, the powder for powder magnetic core, wherein the average crystal grain size in the powder of any 40 or more powders is 50 μm or more.
本発明によれば、圧縮性に優れ、かつ成形後に低鉄損を呈するような圧粉磁芯用粉末を得ることができる。また、特に中高周波（800Hz〜３kHz）における鉄損特性に優れる圧粉磁芯用粉末を得ることができる。 ADVANTAGE OF THE INVENTION According to this invention, the powder for powder magnetic cores which is excellent in compressibility and exhibits a low iron loss after shaping | molding can be obtained. Moreover, the powder for powder magnetic cores which is excellent in the iron loss characteristic especially in a medium high frequency (800 Hz-3 kHz) can be obtained.
以下、本発明について具体的に説明する。
圧粉磁芯用粉末（以下、単に粉末と言った場合は、圧粉磁芯用粉末を意味する）内の結晶粒径は、粉末の圧縮性や、成形後のヒステリシス損などに影響を及ぼす。
そこで、前述したように、発明者らが粉末の結晶粒径や不純物などを鋭意検討した結果、粉末の平均結晶粒径が50μｍよりも細かい場合は、圧縮性を阻害するだけでなく、成形後の結晶粒径が細かくなってヒステリシス損が増加してしまうことが判明した。また、その際の粉末のサンプル数は、任意の40個以上とすることが肝要である。
Hereinafter, the present invention will be specifically described.
The crystal grain size in the powder for the dust core (hereinafter simply referred to as the powder for the dust core) affects the compressibility of the powder and the hysteresis loss after molding. .
Therefore, as described above, the inventors have intensively studied the crystal grain size and impurities of the powder. As a result, when the average crystal grain size of the powder is smaller than 50 μm, not only the compressibility is hindered but also after molding. It has been found that the crystal grain size becomes smaller and the hysteresis loss increases. In addition, it is important that the number of powder samples at that time be 40 or more.
従って、本発明では、粉末の結晶粒径は、任意の40個以上の粉末の粉末内結晶粒径を断面観察した際に、その平均結晶粒径を50μｍ以上とする。より好ましく60μｍ以上である。また、任意の40個以上の粉末の粉末内平均結晶粒径を50μｍとすると、粒界の面積が減少するため、粒内不純物が減少する。そのため、成形後のヒステリシス損がさらに良好になるという効果もある。
なお、本発明において、上記結晶粒径は、以下の方法によって求めることができる。
まず、被測定物である鉄粉（粉末）を、熱可塑性樹脂粉に混合して混合粉としたのち、該混合粉を適当な型に装入後、加熱し樹脂を溶融させたのち冷却固化させ、鉄粉含有樹脂固形物とする。ついで、該鉄粉含有樹脂固形物を任意の断面で切断し、該切断した面を研磨しエッチングしたのち、光学顕微鏡または走査型電子顕微鏡（100倍）を用いて鉄粉粒子の断面組織を観察及び／又は撮像する。撮像した視野内の任意の鉄粉に対して、該鉄粉を横切るように線を引く。このとき、線は鉄粉の中心近傍を横切るように引く。鉄粉内に含まれる線の全長を、該線が横切った結晶粒の個数で割ることにより各鉄粉の結晶粒径を求める。１視野に対し、１０個以上の鉄粉の結晶粒径を求めるが、各鉄粉を横切る線は互いに非平行となるようにする。上記の様な結晶粒径の測定を、４視野以上で行なうことで４０個以上の鉄粉の結晶粒径を求め、それを平均して粉末内平均結晶粒径とする。
Therefore, in the present invention, the crystal grain size of the powder is set to an average crystal grain size of 50 μm or more when the crystal grain size in the powder of any 40 or more powders is observed in cross section. More preferably, it is 60 μm or more. Further, if the average crystal grain size in the powder of any 40 or more powders is 50 μm, the area of the grain boundary is reduced, so that the intragranular impurities are reduced. Therefore, there is an effect that the hysteresis loss after molding is further improved.
In the present invention, the crystal grain size can be determined by the following method.
First, iron powder (powder), which is the object to be measured, is mixed with a thermoplastic resin powder to make a mixed powder, and after charging the mixed powder into an appropriate mold, the resin is heated to melt and then cooled and solidified. To make an iron powder-containing resin solid. Next, the iron powder-containing resin solid material is cut in an arbitrary cross section, the cut surface is polished and etched, and then the cross-sectional structure of the iron powder particles is observed using an optical microscope or a scanning electron microscope (100 times) And / or image. A line is drawn across the iron powder for any iron powder in the field of view. At this time, the line is drawn so as to cross the vicinity of the center of the iron powder. The crystal grain size of each iron powder is determined by dividing the total length of the wire contained in the iron powder by the number of crystal grains crossed by the wire. The crystal grain size of 10 or more iron powders is determined for one field of view, but the lines crossing each iron powder are made non-parallel to each other. Measurement of the crystal grain size as described above is performed with four or more fields of view to determine the crystal grain size of 40 or more iron powders, which are averaged to obtain the average crystal grain size in the powder.
本発明に従う上記粉末は、75μｍ未満、75μｍ以上150μｍ以下、150μｍ超300μｍ以下の３段階の粒度に分割し、mass％でそれぞれの比率を表した場合、75〜150μｍの範囲に存在する質量比率が最も高く、次いで150μｍ超300μｍ以下の質量比率となり、75μｍ未満の質量比率が最も低くなることが重要である。 The powder according to the present invention is divided into three stages of particle sizes of less than 75 μm, 75 μm or more and 150 μm or less, and more than 150 μm and 300 μm or less, and when expressed in mass%, the mass ratio existing in the range of 75 to 150 μm It is important that the mass ratio is the highest, then more than 150 μm and not more than 300 μm, and the mass ratio less than 75 μm is the lowest.
75〜150μｍの粒度を有する粉末は、モーター用途における磁束密度（１〜２Ｔ）および周波数（800Hz〜３kHz）の範囲で、ヒステリシス損と渦電流損のバランスが良く、結果的に最も低損失となる粉末であるため、粉末中の比率を最も高くするのが好ましい。具体的には、40％を下限とし、好ましくは50％以上とするのが良い。なお、上限は、60％とすることが好ましい。 Powder having a particle size of 75 to 150 μm has a good balance between hysteresis loss and eddy current loss in the range of magnetic flux density (1 to 2 T) and frequency (800 Hz to 3 kHz) in motor applications, and the lowest loss is obtained as a result. Since it is a powder, it is preferable to make the ratio in the powder the highest. Specifically, 40% is the lower limit, preferably 50% or more. The upper limit is preferably 60%.
150μｍより粗粉は、ヒステリシス損が低く、塑性変形が容易であるため、粉末中にある程度の比率で添加することによりヒステリシス損の改善及び圧縮性の改善が見込める。しかしながら、粒径が300μｍを超える粗粉が含まれると、渦電流損の増加が顕著になる。
従って、本発明における粉末の粒度は300μｍ以下とし、粉末中の粗粉の粒度は、150μｍ超300μｍ以下の範囲とする。また、粉末中における上記粗粉の比率が75μｍ以上150μｍ以下の粒度の比率を超えると、渦電流損の増加が顕著になるため、150μｍ超300μｍ以下の粗粉の比率は75〜150μｍの粒度の比率を超えないことが重要である。なお、具体的には、40％未満程度とするのが良い。
Coarse powders of less than 150 μm have a low hysteresis loss and are easily plastically deformed. Therefore, an improvement in hysteresis loss and an improvement in compressibility can be expected by adding them to the powder at a certain ratio. However, when coarse particles having a particle size exceeding 300 μm are included, an increase in eddy current loss becomes significant.
Therefore, the particle size of the powder in the present invention is 300 μm or less, and the particle size of the coarse powder in the powder is in the range of more than 150 μm and 300 μm or less. In addition, when the ratio of the coarse powder in the powder exceeds the ratio of the particle size of 75 μm or more and 150 μm or less, the increase in eddy current loss becomes remarkable. Therefore, the ratio of the coarse powder of more than 150 μm and 300 μm or less has a particle size of 75 to 150 μm. It is important not to exceed the ratio. Specifically, it should be less than 40%.
75μｍ未満の微粉は、渦電流損が低く、粗粉の隙間に入り込み、粉末の金型への充填率を上げる効果がある。従って、隙間を埋めるためにある程度存在しなければならないものの、多すぎるとヒステリシス損の増加を招くことになるため、その比率は他の２つの粒度よりも少ないものとする。そのような観点から、75μｍ未満の微粉の比率は20％以上30％未満程度とするのが好ましい。
なお、本発明における粉末の粒度とは、JIS Z 8801−1：2006に規定された飾を用いて分級して得られた値である。
Fine powder of less than 75 μm has a low eddy current loss, enters into the gaps of the coarse powder, and has the effect of increasing the filling rate of the powder into the mold. Therefore, although it must exist to some extent in order to fill the gap, if it is too large, an increase in hysteresis loss will be caused, so that the ratio is smaller than the other two granularities. From such a viewpoint, the ratio of fine powders of less than 75 μm is preferably about 20% or more and less than 30%.
In addition, the particle size of the powder in this invention is the value obtained by classifying using the decoration prescribed | regulated to JIS Z 8801-1: 2006.
また、本発明に従う結晶粒径および粒度分布を有する粉末は、その見掛け密度が3．5g／cm3以上とする。好ましくは4.0g／cm3以上、更に好ましくは4.2g／cm3以上とするのが良い。見掛け密度が3.5g／cm3未満では、金型への充填率が低くなるため、成形時の粉末の変形量が多くなって、ヒステリシス損が増大するうえ、十分な成形体密度が得られないからである。 In addition, the powder having a crystal grain size and a particle size distribution according to the present invention has an apparent density of 3.5 g / cm 3 or more. It is preferably 4.0 g / cm 3 or more, more preferably 4.2 g / cm 3 or more. When the apparent density is less than 3.5 g / cm 3 , the filling rate into the mold is low, so that the amount of powder deformation during molding increases, hysteresis loss increases, and sufficient molded body density cannot be obtained. Because.
更に追記すれば、見掛け密度が3．5g／cm3未満では、成形時における粉末の塑性変形量が大きくなるために、絶縁被覆が剥離しやすくなって、粒子間の絶縁性が低下するため、成形後の渦電流損の増加を招いてしまう。なお、見掛け密度が3．5g／cm3以上の粉末は、水アトマイズ法、ガスアトマイズ法などによって得られる。 In addition, if the apparent density is less than 3.5 g / cm 3 , the amount of plastic deformation of the powder at the time of molding increases, so the insulating coating is easily peeled off, and the insulation between the particles decreases. This leads to an increase in eddy current loss after molding. A powder having an apparent density of 3.5 g / cm 3 or more can be obtained by a water atomizing method, a gas atomizing method, or the like.
本発明の圧粉磁芯用粉末の表面には、絶縁被覆が施されている。この絶縁被覆は、粉末を成形した後の粒子間の絶縁を確保するために必要であり、粒子間の絶縁が可能であれば特に制限はない。しかし、上記圧粉磁芯用粉末を用いて作製される成形体は、成形後に600〜800℃の熱処理を施されるのが一般的であるため、この温度域の熱処理に耐え得る材質のものが好ましく、そのような絶縁被覆としては、シリコーン樹脂、リン酸金属塩やホウ酸金属塩をベースとしたガラス質の絶縁性アモルファス層や、MgO、フォルステライト、タルク、Al203などの金属酸化物、SiO2をベースとした結晶質の被覆などがある。 An insulating coating is applied to the surface of the powder for a dust core according to the present invention. This insulation coating is necessary to ensure insulation between particles after the powder is formed, and there is no particular limitation as long as insulation between particles is possible. However, since the molded body produced using the above powder for powder magnetic core is generally heat-treated at 600 to 800 ° C. after molding, it is made of a material that can withstand heat treatment in this temperature range. preferably, as such an insulating coating, a silicone resin, insulating amorphous layer of glassy which is based on phosphoric acid metal salt and boric acid metal salts and, MgO, forsterite, talc, metal such Al 2 0 3 There are oxides, crystalline coatings based on SiO 2 and the like.
なお、絶縁被覆の被覆量は、粉末全体に対し、0．05〜５mass％の範囲の添加率とすることが好ましい。被覆量が0.05mass％以上であれば被覆が不均一とならず、絶縁性の低下を招くことがないからであり、一方５mass％以下であれば、圧粉磁芯中の圧粉磁芯用粉末の占める割合が少なくならず、成形体の密度が著しく低下することがないからである。また、粉末に絶縁被覆を形成するためには、粉末に絶縁被覆剤を添加し、混合し、絶縁被覆剤中の溶媒を乾燥させた後、さらに200℃程度の加熱を行い、絶縁被覆の焼付け処理を行うことが好ましい。 In addition, it is preferable that the coating amount of insulation coating shall be the addition rate of the range of 0.05-5 mass% with respect to the whole powder. This is because if the coating amount is 0.05 mass% or more, the coating does not become non-uniform and does not cause a decrease in insulation. On the other hand, if the coating amount is 5 mass% or less, for the dust core in the dust core. This is because the proportion of the powder does not decrease and the density of the molded body does not significantly decrease. In addition, in order to form an insulating coating on the powder, an insulating coating is added to the powder, mixed, and after drying the solvent in the insulating coating, further heating at about 200 ° C. is performed to bake the insulating coating. It is preferable to carry out the treatment.
上記した方法で表面に絶縁被覆を施された圧粉磁芯用粉末は、金型に装入され、所望の寸法形状（圧粉磁芯形状）に加圧成形され、圧粉磁芯とされる。ここで、加圧成形方法は、常温成形法や、金型潤滑成形法など、通常の粉末成形方法がいずれも適用できる。なお、成形圧力は用途に応じて適宜決定されるが、成形圧力を増加すれば、圧粉密度が高くなるため、成形圧力は981MPa（10t／cm2）以上であることが好ましい。より好ましい成形圧力は1471MPa（15t／cm2）以上である。 The powder for the powder magnetic core whose surface is coated with the insulating coating by the above-described method is inserted into a mold and press-molded into a desired dimensional shape (powder magnetic core shape) to obtain a powder magnetic core. The Here, as the pressure molding method, any of ordinary powder molding methods such as a room temperature molding method and a die lubrication molding method can be applied. The molding pressure is appropriately determined depending on the application. However, if the molding pressure is increased, the green density becomes higher. Therefore, the molding pressure is preferably 981 MPa (10 t / cm 2 ) or more. A more preferable molding pressure is 1471 MPa (15 t / cm 2 ) or more.
なお加圧成形に際しては、必要に応じ潤滑材を金型壁面に塗布するか、あるいは粉末に添加することができる。これにより、加圧成形時に金型と粉末との間の摩擦を低減することができ、成形体密度の低下を抑制するとともに、金型から抜出す際の摩擦も低減でき、取出時の成形体（圧粉磁芯）の割れを防止できる。好ましい潤滑材としては、ステアリン酸リチウム、ステアリン酸亜鉛、ステアリン酸カルシウムなどの金属石鹸や、脂肪酸アミド等のワックスなどが挙げられる。 In press molding, if necessary, a lubricant can be applied to the mold wall surface or added to the powder. As a result, the friction between the mold and the powder during pressure molding can be reduced, the decrease in the density of the molded body can be suppressed, and the friction during extraction from the mold can also be reduced. (Dust core) can be prevented from cracking. Preferred lubricants include metal soaps such as lithium stearate, zinc stearate and calcium stearate, and waxes such as fatty acid amides.
成形された圧粉磁芯は、加圧成形後に、歪取りによるヒステリシス損の低減や成形体強度の増加を目的とした熱処理を行っても良い。熱処理条件は、600℃以上で５〜120分程度とすることが好ましい。なお、加熱雰囲気としては、大気中、不活性雰囲気中、還元雰囲気中あるいは真空中が考えられるが、いずれの雰囲気でもなんら問題はない。また雰囲気露点は、用途に応じ適宜決定すればよい。更に、熱処理中の昇温、あるいは降温時に一定の温度で保持する段階を設けても良い。 The molded powder magnetic core may be subjected to heat treatment for the purpose of reducing hysteresis loss due to strain removal and increasing the strength of the molded body after pressure molding. The heat treatment conditions are preferably 600 ° C. or higher and about 5 to 120 minutes. The heating atmosphere may be air, inert atmosphere, reducing atmosphere, or vacuum, but there is no problem in any atmosphere. Moreover, what is necessary is just to determine an atmospheric dew point suitably according to a use. Furthermore, a step of holding at a constant temperature when the temperature is raised or lowered during the heat treatment may be provided.
以下、実施例に基づいて本発明を具体的に述べる。
見掛け密度の異なる４種のベース鉄粉Ａ、Ｂ、Ｃ、Ｄを用意した。Ａ〜Ｄは1000℃で90分の仕上げ還元を行った後、JIS Z 8801−1：2006に規定された篩で分級した。Ｂについては、分級条件の異なるB1〜B7のものを作製した。また、Ｂの一部は仕上げ還元温度をそれぞれ950℃および850℃としたB8およびB9も準備した。
Hereinafter, the present invention will be specifically described based on examples.
Four types of base iron powders A, B, C, and D having different apparent densities were prepared. A to D were subjected to final reduction at 1000 ° C. for 90 minutes, and then classified with a sieve defined in JIS Z 8801-1: 2006. Regarding B, B1 to B7 having different classification conditions were prepared. A part of B was also prepared as B8 and B9 with final reduction temperatures of 950 ° C. and 850 ° C., respectively.
全ての試料の粒度分布、結晶粒径及び見掛け密度は表１に記載したとおりである。
また、ベース鉄粉Ａ、Ｂ、Ｃ、Ｄは、焼鈍後、シリコーン樹脂による絶縁被覆を施した。シリコーン樹脂はトルエンに溶解させて、シリコーン樹脂が0.9mass％となる希釈溶液を作製し、その後粉末に対する添加率が0.15mass％となるように粉末と希釈溶液を混合し、大気中で乾燥させた。
The particle size distribution, crystal grain size and apparent density of all samples are as described in Table 1.
Moreover, the base iron powders A, B, C, and D were subjected to insulation coating with a silicone resin after annealing. The silicone resin was dissolved in toluene to prepare a diluted solution in which the silicone resin was 0.9 mass%, and then the powder and the diluted solution were mixed so that the addition rate with respect to the powder was 0.15 mass% and dried in the air. .
さらに、上記乾燥後に、大気中、200℃で120分のシリコーン樹脂による絶縁被覆の焼付け処理を行うことにより被覆鉄基軟磁牲粉末である圧粉磁芯用粉末をそれぞれ得た。ついで、これらの粉末を、成形圧1471MPa（15t／cm2）として、潤滑剤（ステアリン酸亜鉛）を金型壁面に塗布する金型潤滑で成形し、外形：38mm、内径：25mm、高さ：６mmのリング状試験片を作製した。作製した試験片は窒素中で、700℃、45分の熱処理を行い、四端子法により比抵抗を測定した。
また、比抵抗測定後は、巻き線を行い（１次巻300ターン、２次巻40ターン）、10000Ａ／ｍにおける磁束密度（メトロン技研製直流磁化測定装置にて測定）と、1.OＴ、１kHzにおける鉄損（アジレント・テクノロジー（株）社製5060A型にて測定）を測定した。
以上の測定により得られた、各試料の成形体密度、磁束密度、比抵抗および鉄損の測定結果をそれぞれ表２に示す。
Further, after the drying, an insulating coating was baked with a silicone resin for 120 minutes at 200 ° C. in the air to obtain powdered magnetic core powders as coated iron-based soft magnetic powders. Next, these powders were molded by mold lubrication with a molding pressure of 1471 MPa (15 t / cm 2 ) and a lubricant (zinc stearate) applied to the mold wall surface. External shape: 38 mm, internal diameter: 25 mm, height: A 6 mm ring-shaped test piece was produced. The prepared test piece was heat-treated in nitrogen at 700 ° C. for 45 minutes, and the specific resistance was measured by a four-terminal method.
After measuring the specific resistance, winding was performed (primary volume 300 turns, secondary volume 40 turns), and the magnetic flux density at 10000 A / m (measured with a DC magnetization measuring device manufactured by Metron Giken), 1.OT, The iron loss at 1 kHz (measured with Agilent Technology Co., Ltd. 5060A type) was measured.
Table 2 shows the measurement results of the compact density, magnetic flux density, specific resistance, and iron loss of each sample obtained by the above measurement.
表２に示したとおり、本発明に従う粉末から作製したリング状試験片は、磁束密度が1.65Ｔ以上と高く、かつ鉄損が100Ｗ／kg以下と低く良好な磁気特性を示していた。これに対し、本発明の条件を外れた比較例は、磁束密度と鉄損の少なくともいずれかに劣っていた。なお、試料Ｎｏ．Ｄは、鉄損（We）値が極めて高く、測定できなかった。 As shown in Table 2, the ring-shaped test piece prepared from the powder according to the present invention had a magnetic flux density as high as 1.65 T or more and an iron loss as low as 100 W / kg or less, which showed good magnetic properties. On the other hand, the comparative example which deviated from the conditions of the present invention was inferior to at least one of magnetic flux density and iron loss. Sample No. D had an extremely high iron loss (We) value and could not be measured.
Claims (1)
該粉末の粒度を、300μｍ以下150μｍ超、150μｍ以下75μｍ以上、75μｍ未満に３分割した時、150μｍ以下75μｍ以上の質量比率が最も高く、ついで300μｍ以下150μｍ超の質量比率であり、75μｍ未満の質量比率が最も低く、
かつ、該粉末の見掛け密度は3.5g／cm3以上であり、
さらに、任意の40個以上の該粉末の粉末内平均結晶粒径が50μｍ以上であることを特徴とする圧粉磁芯用粉末。 A powder for a powder magnetic core having an insulating coating on the surface and a particle size of 300 μm or less,
When the particle size of the powder is divided into 300 μm or less and more than 150 μm, 150 μm or less and 75 μm or more and less than 75 μm, the mass ratio of 150 μm or less and 75 μm or more is the highest, then the mass ratio is 300 μm or less and more than 150 μm, and the mass is less than 75 μm The lowest ratio,
And the apparent density of the powder is 3.5 g / cm 3 or more,
Further, the powder for powder magnetic core, wherein the average crystal grain size in the powder of any 40 or more powders is 50 μm or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2012053335A JP6035788B2 (en) | 2012-03-09 | 2012-03-09 | Powder for dust core |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2012053335A JP6035788B2 (en) | 2012-03-09 | 2012-03-09 | Powder for dust core |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2013187480A true JP2013187480A (en) | 2013-09-19 |
| JP6035788B2 JP6035788B2 (en) | 2016-11-30 |
Family
ID=49388636
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2012053335A Active JP6035788B2 (en) | 2012-03-09 | 2012-03-09 | Powder for dust core |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP6035788B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20170106415A (en) | 2015-02-09 | 2017-09-20 | 제이에프이 스틸 가부시키가이샤 | Raw material powder for soft magnetic powder, and soft magnetic powder for dust core |
| US10109406B2 (en) | 2013-04-19 | 2018-10-23 | Jfe Steel Corporation | Iron powder for dust core and insulation-coated iron powder for dust core |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH062007A (en) * | 1992-06-19 | 1994-01-11 | Kobe Steel Ltd | Pure iron powder for powder metallurgy excellent in compressibility and magnetic characteristic |
| JP2002043125A (en) * | 1999-12-09 | 2002-02-08 | Sumitomo Electric Ind Ltd | Electromagnetic actuator and valve opening/closing mechanism for internal combustion engine using the same |
| JP2005232535A (en) * | 2004-02-19 | 2005-09-02 | Jfe Steel Kk | Iron powder for powder magnetic core, and powder magnetic core |
| JP2005325373A (en) * | 2004-05-12 | 2005-11-24 | Jfe Steel Kk | Method for casting iron powder for magnetic material |
| JP2007092162A (en) * | 2005-02-03 | 2007-04-12 | Jfe Steel Kk | Highly compressive iron powder, iron powder for dust core using the same and dust core |
| JP2008063650A (en) * | 2006-09-11 | 2008-03-21 | Kobe Steel Ltd | Dust core, and iron based powder for dust core |
| JP2010047788A (en) * | 2008-08-19 | 2010-03-04 | Kobe Steel Ltd | Iron base alloy water atomized powder and method for producing the iron base alloy water atomized powder |
-
2012
- 2012-03-09 JP JP2012053335A patent/JP6035788B2/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH062007A (en) * | 1992-06-19 | 1994-01-11 | Kobe Steel Ltd | Pure iron powder for powder metallurgy excellent in compressibility and magnetic characteristic |
| JP2002043125A (en) * | 1999-12-09 | 2002-02-08 | Sumitomo Electric Ind Ltd | Electromagnetic actuator and valve opening/closing mechanism for internal combustion engine using the same |
| JP2005232535A (en) * | 2004-02-19 | 2005-09-02 | Jfe Steel Kk | Iron powder for powder magnetic core, and powder magnetic core |
| JP2005325373A (en) * | 2004-05-12 | 2005-11-24 | Jfe Steel Kk | Method for casting iron powder for magnetic material |
| JP2007092162A (en) * | 2005-02-03 | 2007-04-12 | Jfe Steel Kk | Highly compressive iron powder, iron powder for dust core using the same and dust core |
| JP2008063650A (en) * | 2006-09-11 | 2008-03-21 | Kobe Steel Ltd | Dust core, and iron based powder for dust core |
| JP2010047788A (en) * | 2008-08-19 | 2010-03-04 | Kobe Steel Ltd | Iron base alloy water atomized powder and method for producing the iron base alloy water atomized powder |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10109406B2 (en) | 2013-04-19 | 2018-10-23 | Jfe Steel Corporation | Iron powder for dust core and insulation-coated iron powder for dust core |
| KR20170106415A (en) | 2015-02-09 | 2017-09-20 | 제이에프이 스틸 가부시키가이샤 | Raw material powder for soft magnetic powder, and soft magnetic powder for dust core |
Also Published As
| Publication number | Publication date |
|---|---|
| JP6035788B2 (en) | 2016-11-30 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP5501970B2 (en) | Powder magnetic core and manufacturing method thereof | |
| JP4134111B2 (en) | Method for producing insulating soft magnetic metal powder compact | |
| JP5739348B2 (en) | Reactor and manufacturing method thereof | |
| JP5522173B2 (en) | Composite magnetic body and method for producing the same | |
| JP2010251696A (en) | Soft magnetic powder core and method of manufacturing the same | |
| JP2016171167A (en) | Magnetic sheet material arranged by use of powder compact, and method for manufacturing the same | |
| JP2004288983A (en) | Dust core and method for manufacturing same | |
| JP2008172257A (en) | Method for manufacturing insulating soft magnetic metal powder molding | |
| JP6578083B2 (en) | Low noise reactor, dust core and manufacturing method thereof | |
| CA2891206C (en) | Iron powder for dust cores | |
| JPWO2010038441A1 (en) | Composite magnetic material and manufacturing method thereof | |
| JP6056862B2 (en) | Iron powder for dust core and insulation coated iron powder for dust core | |
| JP5023041B2 (en) | Powder magnetic core and manufacturing method thereof | |
| WO2015151486A1 (en) | Iron powder for dust core, and sorting method for iron powder for dust core | |
| JP2011243830A (en) | Powder magnetic core and method for manufacturing the same | |
| JP4750471B2 (en) | Low magnetostrictive body and dust core using the same | |
| JP6035788B2 (en) | Powder for dust core | |
| JP4849500B2 (en) | Powder magnetic core and manufacturing method thereof | |
| JP6111524B2 (en) | Manufacturing method of dust core | |
| JP2006183121A (en) | Iron based powder for powder magnetic core and powder magnetic core using the same | |
| JP7418194B2 (en) | Manufacturing method of powder magnetic core | |
| JP6757548B2 (en) | Low noise reactor, dust core and its manufacturing method | |
| JP2015015364A (en) | Low-noise reactor, powder-compact magnetic core, and method for manufacturing the same | |
| WO2022196315A1 (en) | Powder for magnetic core, method for manufacturing same, and dust core | |
| JP5929819B2 (en) | Iron powder for dust core |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20150120 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20151228 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20160105 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20160304 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20161004 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20161017 |
|
| R150 | Certificate of patent or registration of utility model |
Ref document number: 6035788 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |