JPH08269501A - High frequency dust core, iron powder therefor and manufacture of the same - Google Patents
High frequency dust core, iron powder therefor and manufacture of the sameInfo
- Publication number
- JPH08269501A JPH08269501A JP7073715A JP7371595A JPH08269501A JP H08269501 A JPH08269501 A JP H08269501A JP 7073715 A JP7073715 A JP 7073715A JP 7371595 A JP7371595 A JP 7371595A JP H08269501 A JPH08269501 A JP H08269501A
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- iron powder
- powder
- frequency
- dust core
- high frequency
- Prior art date
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、電源装置用チョークコ
イル等に用いられる高周波圧粉磁心および高周波圧粉磁
心用鉄粉とそれらの製造方法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency powder magnetic core used for a choke coil for a power supply device, an iron powder for a high-frequency powder magnetic core, and a manufacturing method thereof.
【０００２】[0002]
【従来の技術】従来、圧粉磁心用鉄粉には、鉄粉をボー
ルミル等で偏平加工した鉄粉、焼結用アトマイズ鉄粉、
還元鉄粉、その他電解鉄粉が用いられている。この内、
偏平鉄粉と電解鉄粉は偏平加工することにより各々の鉄
粉の反磁界係数を下げ、磁気特性を向上できることが知
られている。2. Description of the Related Art Conventionally, iron powder for dust cores includes iron powder obtained by flattening iron powder with a ball mill, atomizing iron powder for sintering,
Reduced iron powder and other electrolytic iron powder are used. Of this,
It is known that flat iron powder and electrolytic iron powder can be flattened to reduce the demagnetizing factor of each iron powder and improve the magnetic characteristics.
【０００３】しかし、現実の粉末成形機において、各々
の鉄粉の偏平面を圧粉面にそろえることが不可能であっ
たため、特に、低周波側 (100kHz以下) で交流初透磁率
(μ iac ) が高い値が要求される分野において、μiac
は10％程度低くなり、偏平鉄粉の特性が十分活かしきれ
ない状態であった。However, in the actual powder molding machine,
It was impossible to align the flat surface of the iron powder of
Therefore, especially the AC initial permeability on the low frequency side (100 kHz or less)
(μ iac) Is required in a field requiring a high value, μiac
Is 10% lower, and the characteristics of flat iron powder cannot be fully utilized.
There was no state.
【０００４】また、高純度鉄粉に比べて不純物量が多い
普通の圧粉磁心用偏平鉄粉は、６〜８時間ボールミル等
で偏平加工されたのち、 800℃以上の温度で還元焼鈍さ
れ、250μm 以下に解粒されて用いられる。一方、高純
度鉄粉は普通鉄粉と同様に 800℃以上の温度で還元焼鈍
される方が酸素量は低くなるが、偏平鉄粉同士の焼結が
進み過ぎ解粒が不十分になる。このように、普通鉄粉と
高純度鉄粉に解粒に差が生じるのは、表１に一例を示す
ように、高純度鉄粉は普通鉄粉に比べてMn、P、S 、O
が低くなっているからである。還元焼鈍温度が低い場合
は、酸素量が高くなるが解粒は容易である。しかし、還
元焼鈍温度が低く酸素量が多い場合も、還元焼鈍温度が
高く解粒が不十分の場合も交流磁気特性が劣化し問題と
なる。Ordinary flat iron powder for dust cores, which has more impurities than high-purity iron powder, is flattened by a ball mill for 6 to 8 hours and then reduced and annealed at a temperature of 800 ° C. or higher. It is used after being crushed to 250 μm or less. On the other hand, high-purity iron powder has a lower oxygen content when it is subjected to reduction annealing at a temperature of 800 ° C or higher, like ordinary iron powder, but the sintering of flat iron powder progresses too much and granulation becomes insufficient. In this way, the difference in the disintegration between the ordinary iron powder and the high-purity iron powder is that the high-purity iron powder is Mn, P, S, O as compared with the ordinary iron powder as shown in Table 1.
Is low. When the reduction annealing temperature is low, the amount of oxygen is high, but disintegration is easy. However, even when the reduction annealing temperature is low and the amount of oxygen is large, or when the reduction annealing temperature is high and the disintegration is insufficient, the AC magnetic characteristics are deteriorated, which causes a problem.
【０００５】[0005]
【表１】 [Table 1]
【０００６】さらに、圧粉磁心の製造は、鉄粉に樹脂、
水ガラス等の絶縁バインダーを混ぜてプレス成形したも
のを 200℃以下の温度で硬化焼鈍して製造していた。 2
00℃以下の温度では、鉄粉と絶縁バインダーである樹
脂、水ガラス等は雰囲気が大気であっても酸化されるこ
ともなく、圧粉磁心の磁気特性も劣化されない。しか
し、 200℃以下の温度では、成形時に受けた鉄粉の歪み
はほとんど除去できないため、本来鉄粉の持つ磁気特性
を十分引き出せないままである。Further, in the manufacture of dust cores, iron powder is used as a resin,
It was manufactured by press-molding a mixture of insulating binders such as water glass that was press-annealed at a temperature below 200 ° C. 2
At a temperature of 00 ° C. or less, iron powder, resin as an insulating binder, water glass, etc. are not oxidized even in the atmosphere, and the magnetic characteristics of the dust core are not deteriorated. However, at temperatures below 200 ° C, the distortion of the iron powder received during molding can hardly be removed, so the magnetic properties inherent to the iron powder cannot be fully extracted.
【０００７】[0007]
【発明が解決しようとする課題】圧粉磁心の磁気特性は
鉄粉粒度に強く依存するので、前記の100kHz以下で高い
μiac が要求される圧粉磁心には、粗粉の偏平鉄粉を用
いることにより磁気特性を向上することが有効である。
また、本発明者は当研究において、これらの粗偏平鉄粉
の偏平面を圧粉面にそろえるのに圧粉速度（成形速度）
が強く影響し、成形体全体において偏平面を圧粉面にそ
ろえるのに必要な圧粉限界速度が存在することを明らか
にした。Since the magnetic characteristics of the dust core strongly depend on the iron powder particle size, a coarse flat iron powder is used for the dust core requiring a high μ iac at 100 kHz or less. It is effective to improve the magnetic properties by using them.
In addition, in the present research, the present inventor used a compacting speed (forming speed) to align the flat surfaces of these coarse flat iron powders with the compacting surface.
Has a strong influence, and it has been clarified that there exists a dust limit velocity necessary for aligning the flat surface with the dust surface in the whole compact.
【０００８】しかし、一般に鉄粉を成形する粉末成形機
には、クランクプレス、カムプレス、ロータリプレス等
が用いられている。これらの機械プレスは下限回転数が
あり、粗偏平鉄粉において、偏平面を圧粉面にそろえる
ことが不可能である。一方、成形速度が自由に変えられ
る油圧プレスは低速度成形が可能であるので、前記粗偏
平鉄粉の成形に適しているといえる。しかし、油圧プレ
スは成形速度が機械プレスに比べて遅いため、小物圧粉
磁心等を成形するのに適していない面があるが、これに
対しては複数個同時成形技術を用いれば工業的に生産で
きると推定される。However, a crank press, a cam press, a rotary press, etc. are generally used for a powder molding machine for molding iron powder. These mechanical presses have a lower limit number of rotations, and it is impossible to align the flat surface with the powder surface in the rough flat iron powder. On the other hand, since a hydraulic press whose molding speed can be freely changed is capable of low speed molding, it can be said that it is suitable for molding the above-mentioned rough flat iron powder. However, since the hydraulic press has a slower forming speed than the mechanical press, it has some aspects that are not suitable for forming small powder magnetic cores, etc. It is estimated that it can be produced.
【０００９】基本的に、偏平鉄粉の交流磁気特性は還元
焼鈍後の酸素量と解粒のされ方によって決まる。従っ
て、解粒の容易さは還元焼鈍温度が低い程良いので、酸
素量を低めるには、還元焼鈍前の酸素量を低めてやるこ
とが重要である。すなわち、ボールミルでの偏平加工中
に増加する酸素量を低い側で制御するとともに、解粒性
の良い還元焼鈍温度を選択することが大事となる。[0009] Basically, the AC magnetic characteristics of flat iron powder are determined by the amount of oxygen after reduction annealing and the manner of disintegration. Therefore, the easier the pulverization is, the lower the reduction annealing temperature is. Therefore, in order to reduce the oxygen amount, it is important to reduce the oxygen amount before the reduction annealing. That is, it is important to control the amount of oxygen that increases during flattening in a ball mill on the low side and select a reduction annealing temperature with good disaggregation.
【００１０】また、成形時に受けた鉄粉の歪みを除去し
てやることは、本来鉄粉の持つ磁気特性を十分引き出す
ために重要なことである。このため、絶縁バインダーを
樹脂、水ガラス等から無機系のりん酸系ガラス絶縁バイ
ンダーに変えることにより、焼鈍温度は 500℃まで高め
られるが、大気雰囲気中では鉄粉や絶縁バインダーは酸
化され、磁気特性が劣化する。このため、大気雰囲気中
での焼鈍では耐熱絶縁バインダーの効果が十分に発揮で
きない。また、歪み取り焼鈍雰囲気中の酸素量が増加す
ると100kHz以下でのμiac の低下が大きくなり、質量の
大きい高周波圧粉磁心の歪み取り焼鈍が不可能になる。
そこで、高純度のアルゴンや窒素ガスを用いることによ
り圧粉磁心の酸化を防ぎ、磁気特性の劣化を防ぐことが
考えられるが、高純度のアルゴンや窒素ガスは高価で、
工場で生産する場合、生産コストを上げるため問題にな
る。Further, it is important to remove the distortion of the iron powder received at the time of molding in order to sufficiently bring out the magnetic characteristics originally possessed by the iron powder. Therefore, by changing the insulating binder from resin, water glass, etc. to inorganic phosphoric acid glass insulating binder, the annealing temperature can be increased to 500 ° C, but iron powder and insulating binder are oxidized in the air atmosphere and The characteristics deteriorate. Therefore, the effect of the heat-resistant insulating binder cannot be sufficiently exhibited by annealing in the air atmosphere. Further, when the amount of oxygen in the strain relief annealing atmosphere increases, the decrease of μ iac at 100 kHz or less becomes large, and the strain relief annealing of the high-frequency high-frequency powder magnetic core becomes impossible.
Therefore, it is possible to prevent oxidation of the dust core by using high-purity argon or nitrogen gas and prevent deterioration of magnetic characteristics, but high-purity argon or nitrogen gas is expensive,
When producing in a factory, it becomes a problem because it raises the production cost.
【００１１】本発明は、上記の問題点を解決するために
なされたもので、圧粉磁心用鉄粉の粒度を限定し、成形
時の圧縮速度を限定することによって、偏平鉄粉の偏平
面を圧粉面にそろえた100kHz以下で高いμiac を有する
高周波圧粉磁心とその製造方法を、また、偏平加工後の
酸素量と還元焼鈍温度を限定することによって、交流磁
気特性を安定化した高周波圧粉磁心用鉄粉とその製造方
法を、さらに、歪み取り焼鈍時の雰囲気中の酸素量を限
定することによって、交流磁気特性の優れた質量の大き
い高周波圧粉磁心が得られる製造方法を提供することを
目的とする。The present invention has been made in order to solve the above-mentioned problems, and limits the particle size of the iron powder for dust cores and the compression speed at the time of molding so that the flat surface of the flat iron powder is flat. A high-frequency powder magnetic core with a high μ iac of 100 kHz or less aligned with the powder surface and its manufacturing method, and by stabilizing the oxygen content and the reduction annealing temperature after flattening, the AC magnetic characteristics were stabilized. Iron powder for high-frequency powder magnetic core and its manufacturing method, further, by limiting the amount of oxygen in the atmosphere at the time of strain relief annealing, a manufacturing method that can obtain a high-frequency powder magnetic core of excellent mass with excellent AC magnetic characteristics The purpose is to provide.
【００１２】[0012]
【課題を解決するための手段】その要旨は、(1) ボール
ミルで偏平加工した 106μm 〜 250μm のアトマイズ鉄
粉の偏平面を、圧粉面に平行にそろえて成形した高周波
圧粉磁心である。[Means for Solving the Problems] The gist is (1) a high-frequency powder magnetic core formed by aligning flat surfaces of atomized iron powder of 106 μm to 250 μm flattened by a ball mill in parallel to the powder surface.
【００１３】(2) 粉末成形機のパンチ圧縮速度を50mm/s
以下の速度で成形する上記(1) の高周波圧粉磁心の製造
方法である。(2) The punch compression speed of the powder molding machine is 50 mm / s.
The method for producing a high-frequency powder magnetic core according to the above (1), which is performed at the following speed.
【００１４】(3) 還元焼鈍後の 250μm 以下の高純度鉄
粉において、 106μm 以上の偏平鉄粉の偏平面の一部ま
たは全面に 106μm 未満の鉄粉が２層以上重なって付着
していない高周波圧粉磁心用鉄粉である。(3) In high-purity iron powder of 250 μm or less after reduction annealing, a high frequency in which two or more layers of iron powder of less than 106 μm do not adhere to part or all of the flat surface of flat iron powder of 106 μm or more Iron powder for dust core.
【００１５】(4) ボールミルで偏平加工後の酸素量が
0.2質量％以下のアトマイズ鉄粉を、700℃〜 780℃の温
度で還元焼鈍する上記(3) の高周波圧粉磁心用鉄粉の製
造方法である。(4) The amount of oxygen after flattening with a ball mill is
The method for producing an iron powder for a high-frequency dust core according to (3) above, wherein 0.2% by mass or less of atomized iron powder is reduction-annealed at a temperature of 700 ° C to 780 ° C.
【００１６】(5) プレス成形した高周波圧粉磁心を、20
ppm 以下の酸素を含む窒素または不活性ガス気流中で歪
み取り焼鈍する高周波圧粉磁心の製造方法である。(5) The press-molded high-frequency powder magnetic core was
This is a method for producing a high-frequency powder magnetic core, in which strain relief annealing is performed in a nitrogen or inert gas stream containing ppm or less oxygen.
【００１７】(6) 高周波圧粉磁心の質量が30g 以上であ
る上記(5) の高周波圧粉磁心の製造方法である。(6) The method for producing a high-frequency powder magnetic core according to the above (5), wherein the mass of the high-frequency powder magnetic core is 30 g or more.
【００１８】[0018]
【作用】ボールミルで偏平加工した 106μm 〜 250μm
の粗粉アトマイズ鉄粉の偏平面を圧粉面に平行にそろえ
て成形しているため100kHz以下で高いμiac を有する高
周波圧粉磁心を得ることができ、同一インダクタンスを
得るのにコイルターン数を減少させた低ターン数磁心
と、また同一ターン数においてはより高いインダクタン
スの磁心を得ることができる。鉄粉の粒度については、
従来からの限定値である 250μm を上限値とし、下限は
図２に示すように高いμiac を確保するために 106μm
以上に限定した。[Operation] 106 μm ~ 250 μm flattened by ball mill
Coarse powder atomized Since the flat surface of the iron powder is aligned in parallel with the dust surface, it is possible to obtain a high frequency dust core with a high μ iac at 100 kHz or less, and the number of coil turns to obtain the same inductance. It is possible to obtain a low-turn-number magnetic core with a reduced value and a higher-inductance magnetic core with the same number of turns. Regarding the particle size of iron powder,
The conventional limit value of 250 μm is set as the upper limit, and the lower limit is 106 μm in order to secure high μ iac as shown in FIG.
Limited to the above.
【００１９】成形時、圧粉面に平行にアトマイズ鉄粉の
偏平面をそろえるために、粉末成形機のパンチ圧縮速度
を50mm/s以下の速度で成形する。パンチ圧縮速度を50mm
/s以下の速度にすることによって、成形過程で鉄粉の偏
平面が圧粉面に平行になるように移動して、偏平面が圧
粉面に平行にそろうようになる。しかし、パンチ圧縮速
度が50mm/sを超えて速くなると、偏平面が圧粉面に平行
にそろうように移動し終わる前に成形が終わり、偏平面
が圧粉面に平行にそろわなくなる。At the time of molding, in order to align the flat surfaces of the atomized iron powder in parallel with the surface of the powder compact, the punching speed of the powder molding machine is 50 mm / s or less. Punch compression speed is 50mm
By setting the speed to be equal to or less than / s, the flat surface of the iron powder moves so as to be parallel to the powder surface in the molding process, and the flat surface comes to be parallel to the powder surface. However, when the punch compression speed becomes higher than 50 mm / s, the molding is finished before the flat surface moves so as to be parallel to the powder surface, and the flat surface is not aligned parallel to the powder surface.
【００２０】ボールミルで偏平加工後の酸素量が 0.2質
量％以下のアトマイズ鉄粉を、 700℃〜 780℃の温度で
還元焼鈍することによって、酸素量の低い高周波圧粉磁
心用鉄粉が得られる。また、還元焼鈍時の酸素量を低く
抑えているため、焼鈍温度を800℃以下の 700℃〜 780
℃にすることができるので、鉄粉同士の焼結が進み過ぎ
ることはなく、還元焼鈍後の鉄粉の解粒は容易である。
このため、還元焼鈍後の 250μm 以下の高純度鉄粉にお
いて、 106μm 以上の偏平鉄粉の偏平面の一部または全
面に 106μm 未満の鉄粉が２層以上重なって付着するこ
とはない。したがって、酸素量の低い、かつ偏平鉄粉厚
が制限された高純度鉄粉が得られるため、従来の偏平鉄
粉に比べてより高周波特性が優れた低鉄損の高周波圧粉
磁心用鉄粉を得ることができる。By ironing atomized iron powder having an oxygen content of 0.2 mass% or less after flattening with a ball mill at a temperature of 700 ° C to 780 ° C by reduction annealing, iron powder for high-frequency dust cores having a low oxygen content can be obtained. . In addition, since the amount of oxygen during reduction annealing is kept low, the annealing temperature should be kept below 800 ° C from 700 ° C to 780 ° C.
Since the temperature can be set to 0 ° C., the sintering of the iron powders does not proceed too much, and the iron powders after reduction annealing are easily disintegrated.
Therefore, in the high-purity iron powder of 250 μm or less after reduction annealing, the iron powder of 106 μm or more does not overlap and adhere to a part or the entire flat surface of the flat iron powder of 106 μm or more. Therefore, since high-purity iron powder with low oxygen content and flat iron powder thickness is obtained, high iron powder for high-frequency dust cores with low iron loss and superior high-frequency characteristics compared to conventional flat iron powder. Can be obtained.
【００２１】20ppm 以下の酸素を含む窒素または不活性
ガス気流中で歪み取り焼鈍を行うため、高純度のアルゴ
ンや窒素ガスを使用する焼鈍よりも生産コストが下が
り、かつ酸素量を限定しているため、無酸化の高周波圧
粉磁心を得ることができる。また、酸素量を20ppm 以下
に低く抑えることで質量が30g 以上の高周波圧粉磁心ま
でこの気流中で歪み取り焼鈍が可能となり、100kHz以下
でのμiac の低下がなくなり優れた磁気特性を有する高
周波圧粉磁心を得ることができる。従って、従来よりも
安価な磁気特性に優れた質量の大きい高周波圧粉磁心が
製造可能になる。Since strain relief annealing is performed in nitrogen or an inert gas stream containing 20 ppm or less of oxygen, the production cost is lower than that of annealing using high-purity argon or nitrogen gas, and the amount of oxygen is limited. Therefore, a non-oxidized high frequency powder magnetic core can be obtained. In addition, by suppressing the oxygen content to 20ppm or less, strain relief annealing can be performed in this air flow even for high-frequency powder magnetic cores with a mass of 30g or more, and there is no decrease in μ iac at 100kHz or less. A dust core can be obtained. Therefore, it is possible to manufacture a high-frequency powder magnetic core having a large mass, which is less expensive than the conventional one and has excellent magnetic characteristics.
【００２２】[0022]
実施例１ 供試粉は 250μm 以下のアトマイズ鉄粉を用いて、ボー
ルミルで偏平加工後還元焼鈍を行い、その後解粒・篩分
けして 250μm 以下を素粉とした。さらに、素粉は 150
μm 以上、 106μm 以上、 106μm 未満に篩分けして、
鉄粉表面を絶縁するためにりん酸系の絶縁液と混合し乾
燥した。絶縁処理した鉄粉は油圧プレスを用いて密度7.
05g/cm3 、外径36mm、内径24mm、長さ10mmに成形した。
成形体は窒素雰囲気中で 475℃で１時間焼鈍し、ＬＣＲ
メータを用いてインダクタンスを測定しμiac を評価し
た。Example 1 Atomized iron powder having a particle size of 250 μm or less was used as a test powder, flattening was performed by a ball mill, reduction annealing was performed, and thereafter, disintegration and sieving were performed to obtain a powder having a particle size of 250 μm or less. In addition, the powder is 150
Sieve to more than μm, more than 106 μm, less than 106 μm,
In order to insulate the iron powder surface, it was mixed with a phosphoric acid-based insulating solution and dried. Insulated iron powder has a density of 7.
It was molded into 05g / cm 3 , outer diameter 36mm, inner diameter 24mm, and length 10mm.
The molded body was annealed at 475 ° C for 1 hour in a nitrogen atmosphere, and LCR
The inductance was measured using a meter and μ iac was evaluated.
【００２３】図１は、油圧プレスのパンチ圧縮速度を20
mm/s〜150mm/s に変えた場合の成形体内部の鉄粉の配列
状態を示す図である。図に示すように、パンチ圧縮速度
が50mm/s以下の場合は、各々の偏平鉄粉の偏平面が圧粉
面に平行になる。一方、パンチ圧縮速度が 100mm/s以上
の場合は、各々の鉄粉が成形時に流れが起こったように
乱れたままの状態で成形されている。パンチ圧縮速度を
50mm/s〜100mm/s では、圧粉面側（図では下側）は比較
的圧粉面に平行であるが、パンチ側（図では上側）が乱
れた状態になる。この乱れる傾向は圧縮速度が速くなる
ほど領域が増していく。すなわち、成形時の偏平鉄粉の
乱れは、パンチ側に起こり易く、パンチ圧縮速度が速い
ほど起こりやすい。FIG. 1 shows a punch compression speed of a hydraulic press of 20.
It is a figure which shows the arrangement | positioning state of the iron powder inside a molded object when changing into mm / s-150 mm / s. As shown in the figure, when the punch compression speed is 50 mm / s or less, the flat surface of each flat iron powder is parallel to the powder surface. On the other hand, when the punch compression speed is 100 mm / s or more, each iron powder is molded in a state of being disturbed as if a flow had occurred during molding. Punch compression speed
At 50 mm / s to 100 mm / s, the dust surface side (lower side in the figure) is relatively parallel to the dust surface, but the punch side (upper side in the figure) is disturbed. This turbulent tendency increases in area as the compression speed increases. That is, the disorder of the flat iron powder during molding is likely to occur on the punch side, and is more likely to occur as the punch compression speed is higher.
【００２４】図２は、パンチ圧縮速度とμiac との関係
を示す図である。図に示すように、偏平鉄粉が 106μm
以上および 150μm 以上の場合は、パンチ圧縮速度が50
mm/sを超えるとμiac が低下し始め、 100mm/sまで低下
し続ける。一方、偏平鉄粉が106μm 未満の場合は、パ
ンチ圧縮速度にあまり依存することなく、μiac はほぼ
一定になっている。FIG. 2 is a diagram showing the relationship between the punch compression speed and μ iac . As shown in the figure, the flat iron powder is 106 μm
Punch punch speed of 50 μm and above and 150 μm and above.
When it exceeds mm / s, μ iac begins to decrease and continues to decrease to 100 mm / s. On the other hand, when the flat iron powder is less than 106 μm, μ iac is almost constant without much depending on the punch compression speed.
【００２５】図３は、パンチ圧縮速度が50mm/s以下の場
合の偏平鉄粉中の 106μm 以上の鉄粉量とμiac との関
係を示す図である。図に示すように、パンチ圧縮速度が
50mm/s以下であれば、μiac は 106μm 以上の鉄粉量に
比例して大きくなっている。これは複合則に従っている
ことがわかる。このように、高周波圧粉磁心用鉄粉には
粗偏平鉄粉が優れていることがわかる。FIG. 3 is a diagram showing the relationship between the iron powder amount of 106 μm or more in the flat iron powder and μ iac when the punch compression speed is 50 mm / s or less. As shown in the figure, the punch compression speed is
Below 50 mm / s, μ iac increases in proportion to the amount of iron powder above 106 μm. It can be seen that this follows a compound rule. Thus, it is understood that the rough flat iron powder is excellent as the iron powder for the high-frequency dust core.
【００２６】以上の結果からも明らかなように、 106μ
m 以上、 250μm 以下の偏平鉄粉を、50mm/s以下のパン
チ圧縮速度で成形することによって、鉄粉の偏平面が圧
粉面に平行にそろったμiac の大きい高周波圧粉磁心を
得ることができる。As is clear from the above results, 106 μ
By molding flat iron powder of m or more and 250 μm or less at a punch compression speed of 50 mm / s or less, a high-frequency dust core with a large μ iac in which the flat surfaces of the iron powder are aligned parallel to the dust surface is obtained. You can
【００２７】実施例２ 供試鉄粉は 250μm 以下のアトマイズ鉄粉を用いて、ボ
ールミルでの偏平加工後還元焼鈍を行い、その後解粒を
行った。表２にボールミルでの偏平加工時間、偏平加工
後の酸素量、還元焼鈍温度、還元焼鈍後の酸素量を示
す。図４に還元焼鈍後に解粒された鉄粉の形状例を示
す。実施例１と同様に、これらの鉄粉をりん酸系の絶縁
液で絶縁処理し、油圧プレスを用いて密度6.95g/cm3 、
外径36mm、内径24mm、長さ 5mmに成形後、窒素雰囲気中
で 475℃で１時間焼鈍した。このようにして得られた高
周波圧粉磁心のμiac の周波数依存性を図５に示す。Example 2 As the iron powder to be tested, atomized iron powder having a size of 250 μm or less was used, and reduction annealing was carried out after flattening with a ball mill, followed by disintegration. Table 2 shows the flattening time in the ball mill, the amount of oxygen after flattening, the reduction annealing temperature, and the amount of oxygen after reduction annealing. FIG. 4 shows an example of the shape of iron powder disintegrated after reduction annealing. In the same manner as in Example 1, these iron powders were insulated with a phosphoric acid-based insulating liquid, and the density was 6.95 g / cm 3 using a hydraulic press.
After molding to have an outer diameter of 36 mm, an inner diameter of 24 mm and a length of 5 mm, it was annealed at 475 ° C for 1 hour in a nitrogen atmosphere. FIG. 5 shows the frequency dependence of μ iac of the high-frequency dust core thus obtained.
【００２８】[0028]
【表２】 [Table 2]
【００２９】表２において、No.1、2 、3 を比較すると
還元焼鈍後の酸素量は、偏平加工後の酸素量に依存し、
特に、No.3では還元焼鈍後の酸素量が多い。従って、偏
平加工後の酸素量は 0.2質量％以下であることが重要で
ある。また、No.1、4 、5 を比較すると還元焼鈍温度が
高いほど、還元焼鈍後の酸素量は低くなっているが、図
４に示すように、No.5は還元焼鈍温度が高いため鉄粉同
士の焼結が進み、解粒できない。従って、還元焼鈍温度
は 700℃〜 780℃が望ましい。In Table 2, comparing Nos. 1, 2, and 3, the amount of oxygen after reduction annealing depends on the amount of oxygen after flattening,
Especially, in No. 3, the amount of oxygen after reduction annealing is large. Therefore, it is important that the oxygen content after flattening is 0.2 mass% or less. Also, comparing Nos. 1, 4, and 5, the higher the reduction annealing temperature, the lower the oxygen content after reduction annealing. However, as shown in FIG. Sintering of the powders progresses and the particles cannot be disintegrated. Therefore, the reduction annealing temperature is preferably 700 ° C to 780 ° C.
【００３０】図４において、No.1と 2の 106μm 以上の
鉄粉の偏平面には、 106μm 未満の微粉は付着せず、偏
平加工されたままの厚さを保っている。No.4は 106μm
以上の鉄粉の偏平面の一部に 106μm 未満の微粉が付着
している。No.5は 106μm 以上の鉄粉の偏平面の全面に
２層以上重なって 106μm 未満の微粉が付着している。
これら付着した微粉は機械的に解粒できないことから、
かなり強固に 106μm以上の鉄粉表面に焼結しているも
のと推察される。一方、No.1、2 、3 、4 、5におい
て、 106μm 未満の微粉は 106μm 以上の偏平鉄粉のよ
うに微粉の付着はない。前記理由として、一般に粉末は
接触する粉末の大きさの差が大きい程、焼結速度が大き
いことが熱力学的に言える。前述の場合、 106μm 以上
の粗粉と微粉の焼結速度は微粉同士の場合に比べて大き
い。従って、焼結速度は粉末同士の接着力に等しいと考
えられるので、焼結後の機械的な解粒において粗粉／微
粉の場合は、微粉／微粉に比べて解粒されにくいと推定
される。In FIG. 4, fine powder of less than 106 μm does not adhere to the flat surfaces of No. 1 and 2 iron powder of 106 μm or more, and the flattened thickness is maintained. No. 4 is 106 μm
Fine powder of less than 106 μm adheres to part of the above flat surface of iron powder. In No. 5, two or more layers were stacked on the entire flat surface of iron powder of 106 μm or more, and fine powder of less than 106 μm was attached.
Since these fine powders that adhere cannot be mechanically disintegrated,
It is presumed that it is fairly strongly sintered on the iron powder surface of 106 μm or more. On the other hand, in Nos. 1, 2, 3, 4, and 5, the fine powder of less than 106 μm does not adhere to it, unlike the flat iron powder of 106 μm or more. For the above reason, it can be said thermodynamically that the greater the difference in the size of the powders that come into contact with each other, the higher the sintering rate. In the above case, the sintering speed of coarse powder and fine powder of 106 μm or more is higher than that of the fine powders. Therefore, since the sintering speed is considered to be equal to the adhesive force between the powders, it is presumed that in mechanical disintegration after sintering, coarse powder / fine powder is less likely to be disintegrated than fine powder / fine powder. .
【００３１】図５において、No.1、2 、4 のμiac は良
好な周波数依存性を示す。還元焼鈍後の酸素量が高いN
o.3のμiac は周波数が低い側でもNo.1、2 、4 に比べ
て低く、低下も早い。還元焼鈍温度が最も高いNo.5のμ
iac は周波数が低い側で著しく高いが、No.3と同じく低
下が早い。このようにNo.5のμiac の低下が早い理由
は、図４に示すように、 106μm 以上の偏平鉄粉の偏平
面への微粉の付着が著しいことが原因である。従って、
還元焼鈍温度は、 106μm 以上の偏平鉄粉の偏平面の一
部または全面に２層以上重なって 106μm 未満の微粉が
付着しない 780℃が上限と考えられる。In FIG. 5, No. 1, 2, and 4 μ iac show good frequency dependence. High oxygen content after reduction annealing N
The μ iac of o.3 is lower than that of Nos. 1, 2, and 4 even on the low frequency side, and it drops quickly. No. 5 with the highest reduction annealing temperature
iac is remarkably high on the low frequency side, but drops rapidly like No. 3. The reason why μ iac of No. 5 declines quickly is that, as shown in FIG. 4, the adhesion of fine powder to the flat surface of flat iron powder of 106 μm or more is remarkable. Therefore,
The upper limit of reduction annealing temperature is considered to be 780 ° C, at which two or more layers of flat iron powder with a flatness of 106 μm or more are partially or entirely overlapped and fine powder of less than 106 μm does not adhere.
【００３２】以上の結果からも明らかなように、偏平加
工後の酸素量を 0.2質量％以下に限定し、還元焼鈍温度
を 700℃〜 780℃に限定することによって、低周波側で
のμ iac の低下が少ない高周波圧粉磁心用鉄粉を得るこ
とができる。As is clear from the above results, the flatness addition
Limit the amount of oxygen after processing to 0.2 mass% or less, and reduce the annealing temperature.
On the low frequency side by limiting the temperature to 700 ℃ ~ 780 ℃
Of μ iacTo obtain iron powder for high frequency dust core
You can
【００３３】実施例３ 供試鉄粉には、アトマイズ法で製造し、ボールミルで偏
平加工後還元焼鈍した250μm 以下の鉄粉を用いた。鉄
粉は MgO、 Ba(OH)3を含むりん酸水溶液を鉄粉100g当た
り 5mlの割合で混合後、 200℃で乾燥して絶縁処理し
た。成形は絶縁処理した鉄粉に潤滑剤（Ca-ST 0.65mass
％）を添加混合し、密度6.95g/cm3 で表３に示す質量の
高周波圧粉磁心に成形した。成形後の高周波圧粉磁心は
15l/minの窒素気流中で 475℃で１時間焼鈍した。表３
に窒素気流中の酸素濃度および成形後の高周波圧粉磁心
の質量を示す。図６に270gの高周波圧粉磁心のμiac と
周波数との関係を示す。Example 3 As the iron powder to be tested, iron powder having a size of 250 μm or less, which was produced by an atomizing method, flattened by a ball mill and then reduction-annealed, was used. The iron powder was prepared by mixing an aqueous phosphoric acid solution containing MgO and Ba (OH) 3 at a ratio of 5 ml per 100 g of the iron powder, followed by drying at 200 ° C. for insulation treatment. Molding is done by insulating iron powder with lubricant (Ca-ST 0.65mass
%) Were added and mixed, and formed into a high-frequency dust core mass density 6.95 g / cm 3 are shown in Table 3. The high frequency dust core after molding
It was annealed at 475 ° C for 1 hour in a nitrogen stream of 15 l / min. Table 3
Shows the oxygen concentration in the nitrogen stream and the mass of the high-frequency powder magnetic core after molding. FIG. 6 shows the relationship between μ iac and frequency of a 270 g high-frequency powder magnetic core.
【００３４】[0034]
【表３】 [Table 3]
【００３５】No.1は酸素濃度1ppm以下の場合で、正常に
焼鈍されている。No.2、3 は酸素濃度を 10ppmと 20ppm
に上げた場合で、μiac はNo.1に比べてやや低くなって
いるが問題のない範囲である。一方、No.4は酸素濃度を
50ppmまで上げた場合で、μ iac が著しく低下してい
る。従って、焼鈍する場合の酸素濃度は 20ppmまで許さ
れる。No. 1 is normal when the oxygen concentration is 1 ppm or less.
It has been annealed. No.2 and 3 have oxygen concentration of 10ppm and 20ppm
When raised to μiacIs slightly lower than No. 1.
However, there is no problem. On the other hand, No. 4 shows the oxygen concentration
When increased to 50ppm, μ iacIs significantly reduced
It Therefore, the maximum oxygen concentration allowed for annealing is 20ppm.
Be done.
【００３６】図７に高周波圧粉磁心の質量と100kHzから
1000kHz 間のμiac 低下率との関係を示す。なお、この
場合の焼鈍時の窒素気流中の酸素濃度は 50ppmである。
100kHzから1000kHz 間のμiac 低下率は下記式で求め
る。FIG. 7 shows the mass of the high frequency powder magnetic core and 100 kHz.
The relationship with the μ iac decrease rate during 1000 kHz is shown. The oxygen concentration in the nitrogen stream during annealing in this case is 50 ppm.
The μ iac reduction rate between 100kHz and 1000kHz is calculated by the following formula.
【００３７】低下率(%)=［〔μiac (100kHz)−μiac (1
000kHz) 〕／μiac (100kHz)］×100Reduction rate (%) = [[μ iac (100 kHz) −μ iac (1
000kHz)] / μ iac (100kHz)] × 100
【００３８】図７に示すように、高周波圧粉磁心の質量
がNo.7の 30gまではμiac 低下率は僅かであるが、No.6
の 50gになると低下率は増加し始め、質量が増すととも
に低下率は増加し、No.4の270gになると低下率は著しく
増加している。この理由は以下のとおりである。すなわ
ち、鉄粉に磁束が起こると鉄粉に渦電流が発生する。こ
の渦電流は鉄粉粒内を流れる粒内電流と、鉄粉の粒子か
ら粒子へと流れる粒子間電流とがある。高周波圧粉磁心
の質量が大きくなると粒子間電流の割合が多くなり、こ
の結果μiac 低下率が顕著になるものと思われる。As shown in FIG. 7, when the mass of the high frequency powder magnetic core is No. 7 up to 30 g, the μ iac decrease rate is slight, but No. 6
The rate of decrease started to increase at 50 g, and the rate of decrease increased as the mass increased. At 270 g of No. 4, the rate of decrease markedly increased. The reason for this is as follows. That is, when a magnetic flux is generated in the iron powder, an eddy current is generated in the iron powder. This eddy current has an intragranular current flowing in the iron powder particles and an interparticle current flowing from one iron powder particle to another. As the mass of the high-frequency dust core increases, the ratio of the interparticle current increases, and as a result, the μ iac decrease rate becomes prominent.
【００３９】以上の結果からも明らかなように、酸素量
を20ppm 以下に抑えた窒素または不活性ガス気流中で歪
み取り焼鈍することによって、安価に焼鈍できるととも
に、μiac 低下の少ない質量30g 以上の高周波圧粉磁心
を得ることができる。As is clear from the above results, strain relief annealing can be carried out at low cost in a nitrogen or inert gas stream in which the amount of oxygen is suppressed to 20 ppm or less, and a mass of 30 g or more with a small decrease in μ iac can be obtained. It is possible to obtain a high frequency powder magnetic core.
【００４０】[0040]
【発明の効果】以上、述べたところから明らかなよう
に、本発明によれば、交流磁気特性を安定化した高周波
圧粉磁心用鉄粉が得られ、また、この鉄粉を用いること
によって、100kHz以下で高いμiac を有する高周波圧粉
磁心を得ることができる。As is apparent from the above description, according to the present invention, an iron powder for a high frequency powder magnetic core having stabilized AC magnetic characteristics can be obtained, and by using this iron powder, A high frequency powder magnetic core having a high μ iac at 100 kHz or less can be obtained.
【図１】油圧プレスのパンチ圧縮速度を20mm/s〜150mm/
s に変えた場合の成形体内部の鉄粉の配列状態を示す図
である。[Fig.1] Punch compression speed of hydraulic press is 20mm / s ~ 150mm /
It is a figure which shows the arrangement | positioning state of the iron powder inside a molded object when changing to s.
【図２】パンチ圧縮速度とμiac との関係を示す図であ
る。FIG. 2 is a diagram showing a relationship between a punch compression speed and μ iac .
【図３】パンチ圧縮速度が50mm/s以下の場合の偏平鉄粉
中の 106μm 以上の鉄粉量とμ iac との関係を示す図で
ある。[Fig. 3] Flat iron powder when the punch compression speed is 50 mm / s or less
The amount of iron powder of 106 μm or more and μ iacIn the figure showing the relationship with
is there.
【図４】実施例２における還元焼鈍後に解粒された鉄粉
の形状例を示す図である。FIG. 4 is a diagram showing an example of the shape of iron powder disintegrated after reduction annealing in Example 2.
【図５】実施例２における高周波圧粉磁心の交流初透磁
率の周波数依存性を示す図である。FIG. 5 is a diagram showing the frequency dependence of the AC initial magnetic permeability of the high-frequency dust core in Example 2.
【図６】実施例３における270gの高周波圧粉磁心の交流
初透磁率と周波数との関係を示す図である。FIG. 6 is a diagram showing a relationship between AC initial permeability and frequency of a 270 g high-frequency powder magnetic core in Example 3;
【図７】実施例３における高周波圧粉磁心の質量と100k
Hzから1000kHz 間の交流初透磁率低下率との関係を示す
図である。FIG. 7: Mass of high-frequency dust core and 100 k in Example 3
It is a figure which shows the relationship with the alternating current initial magnetic permeability fall rate between Hz and 1000kHz.
Claims (6)
50μm のアトマイズ鉄粉の偏平面を、圧粉面に平行にそ
ろえて成形したことを特徴とする高周波圧粉磁心。1. Flattening with a ball mill, 106 μm to 2
A high-frequency powder magnetic core, which is formed by aligning a flat surface of atomized iron powder of 50 μm parallel to the powder surface.
下の速度で成形することを特徴とする請求項１記載の高
周波圧粉磁心の製造方法。2. The method for producing a high-frequency powder magnetic core according to claim 1, wherein the punch compression speed of the powder molding machine is molded at a speed of 50 mm / s or less.
において、 106μm以上の偏平鉄粉の偏平面の一部また
は全面に 106μm 未満の鉄粉が２層以上重なって付着し
ていないことを特徴とする高周波圧粉磁心用鉄粉。3. In the high-purity iron powder of 250 μm or less after reduction annealing, it is confirmed that two or more layers of iron powder of less than 106 μm do not adhere to part or all of the flat surface of the flat iron powder of 106 μm or more. Iron powder for high-frequency powder magnetic cores.
質量％以下のアトマイズ鉄粉を、 700℃〜 780℃の温度
で還元焼鈍することを特徴とする請求項３記載の高周波
圧粉磁心用鉄粉の製造方法。4. The amount of oxygen after flattening with a ball mill is 0.2.
The method for producing an iron powder for a high-frequency dust core according to claim 3, wherein the atomized iron powder in an amount of not more than mass% is reduction-annealed at a temperature of 700 ° C to 780 ° C.
m 以下の酸素を含む窒素または不活性ガス気流中で歪み
取り焼鈍することを特徴とする高周波圧粉磁心の製造方
法。5. The press-molded high-frequency powder magnetic core is set to 20 pp.
A method for producing a high-frequency powder magnetic core, which comprises performing strain relief annealing in a stream of nitrogen or an inert gas containing m or less oxygen.
請求項５記載の高周波圧粉磁心の製造方法。6. The method for producing a high frequency powder magnetic core according to claim 5, wherein the mass of the high frequency powder magnetic core is 30 g or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7073715A JPH08269501A (en) | 1995-03-30 | 1995-03-30 | High frequency dust core, iron powder therefor and manufacture of the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7073715A JPH08269501A (en) | 1995-03-30 | 1995-03-30 | High frequency dust core, iron powder therefor and manufacture of the same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH08269501A true JPH08269501A (en) | 1996-10-15 |
Family
ID=13526202
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|---|---|---|---|
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| JP2002316050A (en) * | 2001-04-24 | 2002-10-29 | Kawasaki Steel Corp | Iron powder for decomposing organic chlorine compound and method for purifying soil, water and gas stained with the same compound |
| JP2003522298A (en) * | 2000-02-11 | 2003-07-22 | ホガナス アクチボラゲット | Iron powder and method for producing the same |
| WO2005095030A1 (en) * | 2004-03-30 | 2005-10-13 | Sumitomo Electric Industries, Ltd. | Method for producing soft magnetic material, soft magnetic powder and 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 |
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1995
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003522298A (en) * | 2000-02-11 | 2003-07-22 | ホガナス アクチボラゲット | Iron powder and method for producing the same |
| JP2002316050A (en) * | 2001-04-24 | 2002-10-29 | Kawasaki Steel Corp | Iron powder for decomposing organic chlorine compound and method for purifying soil, water and gas stained with the same compound |
| JP4660958B2 (en) * | 2001-04-24 | 2011-03-30 | Ｊｆｅスチール株式会社 | Purification of soil, water and gas contaminated with organochlorine compounds |
| WO2005095030A1 (en) * | 2004-03-30 | 2005-10-13 | Sumitomo Electric Industries, Ltd. | Method for producing soft magnetic material, soft magnetic powder and dust core |
| US7674342B2 (en) | 2004-03-30 | 2010-03-09 | Sumitomo Electric Industries, Ltd. | Method of producing soft magnetic material, soft magnetic powder, and 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 |
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