JP6423705B2 - Metal magnetic powder, method for producing the same, and device - Google Patents
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本発明は、数百ＭＨｚ〜数ＧＨｚ帯域で使用されるデバイス（電子部品）の構成材料として有用な金属磁性粉末、およびその製造方法に関する。また、その金属磁性粉末を用いたデバイスに関する。上記デバイスの代表例として、アンテナ、インダクタ、ＥＭＩフィルタが挙げられる。 The present invention relates to a metal magnetic powder useful as a constituent material of a device (electronic component) used in a band of several hundred MHz to several GHz, and a manufacturing method thereof. The present invention also relates to a device using the metal magnetic powder. Typical examples of the device include an antenna, an inductor, and an EMI filter.
近年、各種携帯端末をはじめ、数百ＭＨｚ〜数ＧＨｚの電波を通信手段に用いる電子機器が普及している。これらの機器に適した小型アンテナとして、金属磁性粉末を樹脂で固めた成形体と、薄い板状の放射体とを組み合わせたタイプの平面アンテナが知られている。ある周波数に適合するアンテナ長は、比透磁率の実数部μ’と比誘電率の実数部ε’の積（μ’×ε’）の１／２乗に反比例することから、アンテナの小型化を図るためには、使用される周波数域で高いμ’が得られる磁性材料を選択することが有利である。このような観点から、ＧＨｚ域の周波数に対応する小型アンテナ用の磁性材料として、金属Ｆｅや金属Ｃｏを主体とする金属磁性粉末が提案されている（特許文献１〜３）。 In recent years, electronic devices that use radio waves of several hundred MHz to several GHz as communication means have become widespread, including various portable terminals. As a small antenna suitable for these devices, a planar antenna of a type in which a molded body obtained by solidifying metal magnetic powder with a resin and a thin plate-like radiator is known. The antenna length suitable for a certain frequency is inversely proportional to the 1/2 power of the product (μ ′ × ε ′) of the real part μ ′ of the relative permeability and the real part ε ′ of the relative permittivity. In order to achieve this, it is advantageous to select a magnetic material that provides a high μ ′ in the frequency range used. From such a viewpoint, metal magnetic powders mainly composed of metal Fe and metal Co have been proposed as magnetic materials for small antennas corresponding to frequencies in the GHz range (Patent Documents 1 to 3).
アンテナ用磁性材料の特性として、アンテナの小型化を図る上では上述のようにμ’が大きいことが有利となる。また、磁性体の損失を低減する上で損失係数ｔａｎδ（μ）、ｔａｎδ（ε）が小さいことが望ましい。さらに、リターンロス（反射損失）を低減する観点からはμ’／ε’比ができるだけ１に近づいて大きいことが望ましい。しかしながら、金属磁性粉末においてこれら全ての特性を同時に向上させることは容易でない。例えば、特許文献１、２に開示の金属磁性粉末では高いμ’が得られ、それに伴ってμ’／ε’比も比較的良好であるが、損失係数ｔａｎδ（μ）が大きい。特許文献３に開示の金属磁性粉末はｔａｎδ（μ）が小さく、磁気損失の低減が図られたが、この文献にμ’／ε’比を改善する手法は開示されておらず、磁気損失低減とリターンロス低減を高レベルで両立させるには至っていない。 As a characteristic of the magnetic material for the antenna, it is advantageous that μ ′ is large as described above in order to reduce the size of the antenna. In order to reduce the loss of the magnetic material, it is desirable that the loss coefficients tan δ (μ) and tan δ (ε) are small. Furthermore, from the viewpoint of reducing the return loss (reflection loss), it is desirable that the μ ′ / ε ′ ratio is as close to 1 as possible. However, it is not easy to improve all these characteristics simultaneously in the metal magnetic powder. For example, the metal magnetic powders disclosed in Patent Documents 1 and 2 obtain a high μ ′, and accordingly, the μ ′ / ε ′ ratio is relatively good, but the loss coefficient tan δ (μ) is large. The metal magnetic powder disclosed in Patent Document 3 has a small tan δ (μ) and a reduction in magnetic loss. However, this document does not disclose a method for improving the μ ′ / ε ′ ratio and reduces magnetic loss. And return loss reduction have not been achieved at a high level.
本発明は、樹脂と混合した成形体において、高いμ’を維持した状態で、リターンロスの指標であるμ’／ε’比の向上、および磁気損失の指標であるｔａｎδ（μ）の低減をハイレベルで両立させることができる金属磁性粉末を提供することを目的とする。また、そのような金属磁性粉末を安定して製造する技術を提供することを目的とする。μ’／ε’比の向上やｔａｎδ（μ）の低減は、アンテナのみならず、インダクタ、ＥＭＩフィルタ等のデバイスにおいても有効となる。これは、インダクタ、ＥＭＩフィルタ等のデバイスでは、高いμ’を維持しつつε’を低減することが、浮遊容量に起因する損失を低減させるために有効となるためである。本発明では、上記特性が改善された材料で構成されるアンテナ、インダクタ、ＥＭＩフィルタを提供する。 The present invention improves the μ ′ / ε ′ ratio, which is an index of return loss, and reduces tan δ (μ), which is an index of magnetic loss, while maintaining a high μ ′ in a molded body mixed with a resin. It aims at providing the metal magnetic powder which can be made compatible in high level. Moreover, it aims at providing the technique which manufactures such a metal magnetic powder stably. Improvement of the μ ′ / ε ′ ratio and reduction of tan δ (μ) are effective not only in the antenna but also in devices such as inductors and EMI filters. This is because, in devices such as inductors and EMI filters, reducing ε ′ while maintaining a high μ ′ is effective for reducing loss due to stray capacitance. The present invention provides an antenna, an inductor, and an EMI filter that are made of a material with improved characteristics.
上記目的を達成するために、本発明では、Ｆｅ−Ｃｏ合金磁性相の周囲にＳｉを含有する非磁性相を有する粒子からなる平均粒子径１００ｎｍ以下の金属磁性粉末であって、ＦｅとＣｏの総量に対するＳｉ含有量が２.０〜１５.０モル％であり、保磁力Ｈｃが７９.６ｋＡ／ｍ以下好ましくは５９.５ｋＡ／ｍ以下、飽和磁化σｓが１４７Ａｍ2／ｋｇ以上好ましくは１５３Ａｍ2／ｋｇ以上である粉末磁気特性を有する金属磁性粉末が提供される。この金属磁性粉末は、当該金属磁性粉末とエポキシ樹脂を９０：１０の質量割合で混合して作製した成形体を磁気測定および誘電測定に供したとき、１ＧＨｚにおいて、複素比透磁率の実数部μ’が２.５０以上、かつ前記μ’と複素比誘電率の実数部ε’の比で表されるμ’／ε’比が０.２５以上１.０未満となる性質を有する。また、前記成形体の前記磁気測定において、透磁率の損失係数ｔａｎδ（μ）が０.０５未満となる性質を有する。ここで、複素比透磁率の虚数部をμ”とするとき、損失係数ｔａｎδ（μ）＝μ”／μ’である。上記磁気測定および誘電測定に供する成形体の樹脂としては、エポキシ樹脂を適用すればよい。 In order to achieve the above object, the present invention provides a metal magnetic powder having an average particle diameter of 100 nm or less, comprising particles having a nonmagnetic phase containing Si around the magnetic phase of Fe-Co alloy, and comprising Fe and Co. The Si content with respect to the total amount is 2.0 to 15.0 mol%, the coercive force Hc is 79.6 kA / m or less, preferably 59.5 kA / m or less, and the saturation magnetization σs is 147 Am 2 / kg or more, preferably 153 Am 2. A metal magnetic powder having powder magnetic properties of at least / kg is provided. This metal magnetic powder has a real part μ of complex relative permeability at 1 GHz when a molded body prepared by mixing the metal magnetic powder and an epoxy resin at a mass ratio of 90:10 is subjected to magnetic measurement and dielectric measurement. 'Is 2.50 or more, and the μ ′ / ε ′ ratio expressed by the ratio of the μ ′ and the real part ε ′ of the complex relative dielectric constant is 0.25 or more and less than 1.0. Further, in the magnetic measurement of the molded body, the loss factor tan δ (μ) of magnetic permeability is less than 0.05. Here, when the imaginary part of the complex relative permeability is μ ″, the loss coefficient tan δ (μ) = μ ″ / μ ′. An epoxy resin may be applied as the resin of the molded body used for the magnetic measurement and dielectric measurement.
上記金属磁性粉末の製造方法として、ＦｅイオンおよびＣｏイオンを含む水溶液に酸化剤を導入して、ＦｅおよびＣｏを成分に持つ前駆体を析出成長させる工程（前駆体形成工程）、
前記前駆体を含む水溶媒中に水溶性のケイ素化合物を添加して混合し、Ｓｉ含有物質を被着した前駆体（以下「Ｓｉ被着前駆体」という）を得る工程（前駆体へのＳｉ被着工程）、
Ｓｉ被着前駆体の乾燥物を還元性ガス雰囲気中で２５０〜６５０℃に加熱することにより、Ｆｅ−Ｃｏ合金磁性相を持つ金属粉末を得る工程（還元工程）、
還元後の金属粉末を酸化雰囲気中２０〜３００℃に保持して金属粉末粒子表層部の酸化反応を進行させ、Ｓｉ酸化物を含む酸化物被覆層を有する粒子で構成される金属粉末を得る工程（徐酸化工程）、
Ｓｉ酸化物を含む酸化物被覆層を有する粒子で構成される金属粉末に対して、還元性ガス雰囲気中での２５０〜６５０℃の加熱処理と、それに続く前記徐酸化工程に従う処理を１回以上実施する工程（還元・徐酸化反復工程）、
を有する製造方法が提供される。
As a method for producing the metal magnetic powder, a step of introducing an oxidizing agent into an aqueous solution containing Fe ions and Co ions to precipitate and grow a precursor having Fe and Co as components (precursor forming step),
A step of adding a water-soluble silicon compound to an aqueous solvent containing the precursor and mixing to obtain a precursor having a Si-containing material deposited thereon (hereinafter referred to as “Si deposition precursor”) (Si to the precursor) Deposition process),
A step of obtaining a metal powder having a Fe—Co alloy magnetic phase by heating the dried Si deposition precursor to 250 to 650 ° C. in a reducing gas atmosphere (reduction step);
The process of obtaining the metal powder comprised by the particle | grains which hold | maintain the metal powder after reduction | restoration in 20-300 degreeC in oxidizing atmosphere, and advance the oxidation reaction of a metal powder particle surface layer part, and have an oxide coating layer containing Si oxide (Slow oxidation process),
One or more times of heat treatment at 250 to 650 ° C. in a reducing gas atmosphere and subsequent treatment according to the gradual oxidation step on the metal powder composed of particles having an oxide coating layer containing Si oxide Steps to be performed (reduction / gradual oxidation repeated step),
A manufacturing method is provided.
また本発明では、ＦｅイオンおよびＣｏイオンを含む水溶液に酸化剤を導入して、ＦｅおよびＣｏを成分に持つ前駆体を析出成長させる工程（前駆体形成工程）、
前駆体の乾燥物を還元性ガス雰囲気中で２５０〜６５０℃に加熱することにより、Ｆｅ−Ｃｏ合金磁性相を持つ金属粉末を得る工程（還元工程）、
還元後の金属粉末を酸化雰囲気中２０〜３００℃に保持して金属粉末粒子表層部の酸化反応を進行させ、酸化物被覆層を有する粒子で構成される金属粉末を得る工程（徐酸化工程）、
前記酸化物被覆層を有する粒子で構成される金属粉末に対して、還元性ガス雰囲気中での２５０〜６５０℃の加熱処理と、それに続く前記徐酸化工程に従う処理を１回以上実施する工程（還元・徐酸化反復工程）、
還元・徐酸化反復工程後の金属粉末と水溶性のケイ素化合物を水溶媒中で混合することにより、粉末粒子表面にＳｉ含有物質を被着させる工程（金属粉へのＳｉ被着工程）
を有する金属磁性粉末の製造方法が提供される。
In the present invention, a step of introducing an oxidizing agent into an aqueous solution containing Fe ions and Co ions to precipitate and grow a precursor having Fe and Co as components (precursor forming step),
A step of obtaining a metal powder having an Fe—Co alloy magnetic phase by heating the dried precursor to 250 to 650 ° C. in a reducing gas atmosphere (reduction step);
The process of obtaining the metal powder comprised by the particle | grains which have an oxide coating layer by advancing the oxidation reaction of the metal powder particle | grain surface layer part by hold | maintaining the metal powder after reduction | restoration at 20-300 degreeC in oxidizing atmosphere (gradual oxidation process) ,
A step of performing at least one heat treatment at 250 to 650 ° C. in a reducing gas atmosphere and subsequent treatment according to the gradual oxidation step on the metal powder composed of particles having the oxide coating layer ( Reduction / slow oxidation repeated process),
A process of depositing a Si-containing substance on the surface of powder particles by mixing the metal powder and water-soluble silicon compound after the reduction and slow oxidation repeated processes in an aqueous solvent (Si deposition process on metal powder)
A method for producing a metal magnetic powder having the following is provided.
上記の前駆体は、オキシ水酸化鉄構造あるいはオキシ水酸化鉄のＦｅサイトの一部をＣｏで置換した構造を持つ。徐酸化工程における前記酸化雰囲気中での処理は、例えば還元後の金属粉末が曝される雰囲気を不活性ガス雰囲気としたのち、当該雰囲気中の酸素濃度を増大させながら２０〜３００℃で金属粉末粒子表層部の酸化反応を進行させる手法が適用できる。 The above precursor has an iron oxyhydroxide structure or a structure in which a part of Fe site of iron oxyhydroxide is substituted with Co. The treatment in the oxidizing atmosphere in the gradual oxidation step is, for example, an atmosphere in which the reduced metal powder is exposed to an inert gas atmosphere, and then the metal powder at 20 to 300 ° C. while increasing the oxygen concentration in the atmosphere. A technique for advancing the oxidation reaction of the particle surface layer can be applied.
上記の前駆体形成工程において、ＦｅイオンおよびＣｏイオンが存在しており、更に希土類元素（Ｙも希土類元素として扱う）、Ａｌ、Ｍｇの１種以上が存在している水溶液に酸化剤を導入して、ＦｅおよびＣｏ、並びに希土類元素、Ａｌ、Ｍｇの１種以上を成分に持つ前駆体を析出成長させるようにしてもよい。 In the precursor forming step, an oxidant is introduced into an aqueous solution in which Fe ions and Co ions are present, and one or more of rare earth elements (Y is also treated as a rare earth element), Al, and Mg are present. Then, a precursor having one or more of Fe and Co, and rare earth elements, Al and Mg as components may be deposited and grown.
また、本発明では、上記金属磁性粉末を使用して形成されたアンテナ、インダクタ、ＥＭＩフィルタが提供される。アンテナとしては、例えば上記の金属磁性粉末を樹脂組成物と混合した成形体を構成部材に有する周波数４３０ＭＨｚ以上の電波を受信、送信または送受信するものが特に好適な対象となる。 The present invention also provides an antenna, an inductor, and an EMI filter that are formed using the metal magnetic powder. As an antenna, for example, an antenna that receives, transmits, or transmits / receives a radio wave having a frequency of 430 MHz or more having a molded body obtained by mixing the above metal magnetic powder with a resin composition as a constituent member is particularly suitable.
本発明によれば、磁気損失の低減とリターンロスの低減を高レベルで両立させることのできる磁性粉末が提供された。本発明は、数百ＭＨｚから数ＧＨｚ帯域で使用されるアンテナの小型化、高性能化に寄与しうる。 According to the present invention, a magnetic powder capable of achieving both a reduction in magnetic loss and a reduction in return loss at a high level has been provided. The present invention can contribute to miniaturization and high performance of an antenna used in a band of several hundred MHz to several GHz.
発明者らは詳細な研究の結果、前駆体を還元焼成して金属磁性粉を得るに際し、
（i）還元焼成前の前駆体に適正量のＳｉ含有物質を被着させておくこと、
（ii）還元焼成後に、徐酸化処理を、途中に還元処理を挟んで繰り返して実施すること、
によって、当該金属磁性粉末を樹脂に混合して得られる成形体において、数百ＭＨｚから数ＧＨｚの周波数域で比誘電率の実数部ε’を低くすることができ、かつ保磁力Ｈｃを下げながら、飽和磁化σｓを向上させることが可能となることにより、当該金属磁性粉末を樹脂に混合して得られる成形体において、数百ＭＨｚから数ＧＨｚの周波数域で比透磁率の実数部μ’が大きく増大し、その結果、μ’／ε’比が増大することを見出した。μ’／ε’比はリターンロスの指標となるパラメータであり、μ’／ε’比の増大はリターンロスの低下を意味する。上記（i）の手法がε’の低下をもたらし、（ii）の手法がσｓの向上によるμ’の向上をもたらす。（ii）の手法がσｓの向上をもたらすメカニズムは現時点で未解明であるが、以下のようなことが考えられる。易酸化性元素であるＳｉは、ＦｅやＣｏなどの金属元素と比べ途中の還元処理でも酸化物として残存しやすい。還元処理と徐酸化処理を繰り返すことにより、粒子表層部の酸化皮膜は次第に非磁性成分であるＳｉ酸化物に富んだ安定した皮膜に改質され、粒子内部は強磁性成分であるＦｅ−Ｃｏ合金に富んだ相に改質されると考えられる。これらの現象が磁気特性の改善に影響しているのではないかと推察される。また、上記（i）（ii）の手法は、上記成形体の損失係数ｔａｎδ（μ）を低く維持する上でも有効であることがわかった。
As a result of detailed studies, the inventors obtained a metal magnetic powder by reducing and firing the precursor,
(I) depositing an appropriate amount of Si-containing material on the precursor before reduction firing;
(Ii) After the reduction firing, the gradual oxidation treatment is repeatedly performed with the reduction treatment in the middle,
Thus, in the molded body obtained by mixing the metal magnetic powder with the resin, the real part ε ′ of the relative permittivity can be lowered in the frequency range of several hundred MHz to several GHz, and the coercive force Hc is lowered. Since it becomes possible to improve the saturation magnetization σs, in the molded body obtained by mixing the metal magnetic powder with the resin, the real part μ ′ of the relative permeability in the frequency range of several hundred MHz to several GHz is It was found that the ratio increased greatly, and as a result, the ratio μ ′ / ε ′ increased. The μ ′ / ε ′ ratio is a parameter that serves as an index of return loss, and an increase in the μ ′ / ε ′ ratio means a decrease in return loss. The method (i) above reduces ε ′, and the method (ii) improves μ ′ by improving σs. The mechanism by which the method (ii) brings about the improvement of σs is not yet elucidated, but the following can be considered. Si, which is an easily oxidizable element, is likely to remain as an oxide even during reduction treatment in the middle compared to metal elements such as Fe and Co. By repeating the reduction treatment and the gradual oxidation treatment, the oxide film on the surface layer of the particle is gradually modified into a stable film rich in Si oxide, which is a nonmagnetic component, and the inside of the particle is a Fe-Co alloy that is a ferromagnetic component. It is thought that it is modified to a rich phase. It is presumed that these phenomena may affect the improvement of magnetic properties. Further, it has been found that the above methods (i) and (ii) are effective in keeping the loss factor tan δ (μ) of the molded body low.
また、前駆体を（ii）の手法によって金属に還元した後に、金属粉末粒子表面にＳｉ含有物質を被着させる手法も、ε’を低くするうえで有効であり、かつ保磁力Ｈｃを下げながら飽和磁化σｓを向上させ、μ’／ε’比を増大させるうえで有効であることがわかった。この場合、上記（i）の手法（前駆体へのＳｉ被着）は省略してもよい。 Moreover, after reducing the precursor to a metal by the method (ii), a method of depositing a Si-containing substance on the surface of the metal powder particles is also effective in lowering ε ′ and lowering the coercive force Hc. It was found that this is effective in improving the saturation magnetization σs and increasing the μ ′ / ε ′ ratio. In this case, the method (i) (Si deposition on the precursor) may be omitted.
《金属磁性粉末》
本発明に従う金属磁性粉末は、Ｆｅ−Ｃｏ合金磁性相の周囲にＳｉを含有する非磁性相の被覆層を有する平均粒子径１００ｎｍ以下の粒子からなる。
〔化学組成〕
ＦｅとＣｏの総量に対するＳｉ含有量（Ｓｉ／（Ｆｅ＋Ｃｏ）モル比）は２.０〜１５.０モル％の範囲に調整されている必要がある。Ｓｉは上述のようにμ’／ε’比を向上させる作用を発揮する。またＳｉが濃化した被覆層は金属磁性粉末の電気抵抗を増大させ、渦電流損に起因するｔａｎδ（μ）を低く維持するうえで有効となる。Ｓｉ含有量が低すぎるとμ’／ε’比の向上作用が十分に発揮されず、リターンロス低減効果が得られない。Ｓｉ含有量が過剰になると非磁性成分の増大に伴い透磁率が低下する。なお、従来から金属磁性粉末には、焼結防止や絶縁性付与などの目的でＡｌを添加することがある。ＡｌとＳｉはともに易酸化性元素である点で共通する。しかし、上述のｔａｎδ（μ）を低く維持しつつ、μ’／ε’比を向上させる効果はＡｌ添加によっては顕在化せず、Ｓｉ添加に特有の効果であるといえる。
《Metallic magnetic powder》
The metal magnetic powder according to the present invention comprises particles having an average particle diameter of 100 nm or less having a coating layer of a nonmagnetic phase containing Si around the Fe—Co alloy magnetic phase.
[Chemical composition]
The Si content (Si / (Fe + Co) molar ratio) with respect to the total amount of Fe and Co needs to be adjusted to a range of 2.0 to 15.0 mol%. Si exhibits the effect of improving the μ ′ / ε ′ ratio as described above. The coating layer enriched with Si is effective in increasing the electrical resistance of the metal magnetic powder and maintaining tan δ (μ) due to eddy current loss low. If the Si content is too low, the effect of improving the μ ′ / ε ′ ratio is not sufficiently exhibited, and the return loss reducing effect cannot be obtained. When the Si content is excessive, the magnetic permeability decreases with an increase in the nonmagnetic component. Conventionally, Al is sometimes added to metal magnetic powder for the purpose of preventing sintering and imparting insulation properties. Al and Si are common in that both are oxidizable elements. However, the effect of improving the μ ′ / ε ′ ratio while maintaining the above-mentioned tan δ (μ) low is not manifested by Al addition, and can be said to be an effect specific to Si addition.
Ｆｅに対するＣｏの含有量（Ｃｏ／Ｆｅモル比）は５〜５５モル％であることが好ましい。
Ｆｅ、Ｃｏ、Ｓｉ以外の金属元素として、希土類元素（Ｙも希土類元素として扱う）、Ａｌ、Ｍｇの１種以上を含有することができる。希土類元素、Ａｌ、Ｍｇは、従来公知の金属磁性粉末の製造工程において必要に応じて添加されるものであり、本発明においてもこれらの元素の含有が許容される。ＦｅとＣｏの総量に対して、希土類元素は１０モル％以下、Ａｌは２０モル％以下、Ｍｇは２０モル％以下の範囲で含有させることが望ましい。また、Ｆｅ、Ｃｏ、Ｓｉ以外の金属元素の総量はＦｅとＣｏの総量に対して２０.０モル％以下とすることが望ましく、１５.０モル％以下とすることがより好ましい。
The content of Co relative to Fe (Co / Fe molar ratio) is preferably 5 to 55 mol%.
As metal elements other than Fe, Co, and Si, one or more of rare earth elements (Y is also treated as a rare earth element), Al, and Mg can be contained. The rare earth elements, Al and Mg are added as necessary in the production process of conventionally known metal magnetic powders, and the inclusion of these elements is allowed in the present invention. It is desirable that rare earth elements be contained in a range of 10 mol% or less, Al 20 mol% or less, and Mg 20 mol% or less with respect to the total amount of Fe and Co. The total amount of metal elements other than Fe, Co, and Si is preferably 20.0 mol% or less, and more preferably 15.0 mol% or less with respect to the total amount of Fe and Co.
〔粒子径〕
金属磁性粉末を構成する粒子の粒子径は、透過型電子顕微鏡（ＴＥＭ）観察により求めることができる。ＴＥＭ画像上である粒子を取り囲む最小円の直径をその粒子の径（長径）と定める。その径は、金属コアの周囲を覆う被覆層を含めた径を意味する。ランダムに選択した３００個の粒子について径を測定し、その平均値を当該金属磁性粉末の平均粒子径とすることができる。本発明では、平均粒子径が１００ｎｍ以下のものを対象とする。平均粒子径が１００ｎｍを超えると渦電流損が増大し、ｔａｎδ（μ）が増大するため好ましくない。平均粒子径は７０ｎｍ以下であることが好ましく、５０ｎｍ以下であることがより好ましい。一方、平均粒子径が１０ｎｍ未満の超微細粉末は、製造コストの上昇や取り扱い性の低下を伴うので、通常、平均粒子径は１０ｎｍ以上とすればよい。平均粒子径は１５ｎｍ以上であることが好ましく、２０ｎｍ以上であることがより好ましい。ＴＥＭ画像上のある粒子について、長径に対して直角方向に測った最も長い部分の長さを短径と呼び、長径／短径の比を軸比と呼ぶ。上記３００個の粒子についての長径の平均値（すなわち平均粒子径）を平均長径、短径の平均値を平均短径と呼ぶとき、平均長径／平均短径で表される平均軸比は、通常、１.０〜２.５の範囲となる。
〔Particle size〕
The particle diameter of the particles constituting the metal magnetic powder can be determined by observation with a transmission electron microscope (TEM). The diameter of the smallest circle surrounding the particle on the TEM image is defined as the particle diameter (major axis). The diameter means a diameter including a coating layer covering the periphery of the metal core. The diameter of 300 randomly selected particles can be measured, and the average value can be used as the average particle diameter of the metal magnetic powder. In the present invention, the average particle size is 100 nm or less. If the average particle diameter exceeds 100 nm, eddy current loss increases and tan δ (μ) increases, which is not preferable. The average particle size is preferably 70 nm or less, and more preferably 50 nm or less. On the other hand, since an ultrafine powder having an average particle diameter of less than 10 nm is accompanied by an increase in production cost and a decrease in handleability, the average particle diameter is usually 10 nm or more. The average particle diameter is preferably 15 nm or more, and more preferably 20 nm or more. For a certain particle on the TEM image, the length of the longest portion measured in the direction perpendicular to the major axis is called the minor axis, and the ratio of major axis / minor axis is called the axial ratio. When the average value of the major axis (that is, the average particle diameter) of the 300 particles is referred to as the average major axis, and the average value of the minor axis is referred to as the average minor axis, the average axial ratio represented by the average major axis / average minor axis is usually The range is 1.0 to 2.5.
〔粉末の磁気特性〕
粉末の磁気特性としては、本発明で対象とするアンテナ用途の場合、保磁力Ｈｃは大きいほどｔａｎδ（μ）が小さくなるため望ましいが、大きすぎるとμ’が低下するため、７９.６ｋＡ／ｍ以下であることが望ましく、通常、３９.８〜７９.６ｋＡ／ｍであればよい。３９.８〜７１.６ｋＡ／ｍであることがより望ましい。飽和磁化σｓは大きいほどμ’が大きくなるため有利となる。種々検討の結果、σｓは１４７Ａｍ2／ｋｇ以上であることが望ましく、通常、１４７〜１７０Ａｍ2／ｋｇであれば実用範囲内である。σｓが１４７Ａｍ2／ｋｇを下回るとμ’の低下が大きくなり、アンテナに使用した際に顕著な小型化を図ることが難しくなる。Ｓｉ酸化物を含む酸化物被覆層を有し、かつＳｉ／（Ｆｅ＋Ｃｏ）モル比が上述のように調整されている金属磁性粉末において、上記のような保磁力Ｈｃおよび飽和磁化σｓを有するものは、後述の成形体評価により、μ’が大きく、リターンロスが小さく、磁気損失が小さい、アンテナに好適な磁気特性が得られる。
[Magnetic properties of powder]
As the magnetic properties of the powder, in the case of the antenna application targeted by the present invention, the larger the coercive force Hc, the smaller the tan δ (μ), which is desirable. The following is desirable, and it may be 39.8-79.6 kA / m normally. More preferably, it is 39.8-71.6 kA / m. As the saturation magnetization σs increases, μ ′ increases, which is advantageous. As a result of various studies, it is desirable that σs is 147 Am 2 / kg or more. Usually, 147 to 170 Am 2 / kg is within the practical range. When σs is less than 147 Am 2 / kg, the decrease in μ ′ increases, making it difficult to achieve a significant downsizing when used in an antenna. A metal magnetic powder having an oxide coating layer containing Si oxide and having a Si / (Fe + Co) molar ratio adjusted as described above has a coercive force Hc and a saturation magnetization σs as described above. According to the molded body evaluation described later, magnetic characteristics suitable for an antenna with a large μ ′, a small return loss, and a small magnetic loss can be obtained.
その他の粉末特性として、ＢＥＴ比表面積は３０〜１００ｍ2／ｇ、ＴＡＰ密度は０.８〜１.５ｇ／ｃｍ3、角形比ＳＱは０.３〜０.６、ＳＦＤは３.５以下の範囲にそれぞれあることが好ましい。耐候性については、金属磁性粉末を温度６０℃、相対湿度９０％の空気環境に１週間保持する試験前後のσｓの変化量率を表すΔσｓは２０％以下であることが好ましい。ここで、Δσｓ（％）は（試験前のσｓ−試験後のσｓ）／試験前のσｓ×１００によって算出される。絶縁性については、ＪＩＳ Ｋ６９１１に準拠した二重リング電極方法により、金属磁性粉末１.０ｇを電極間に挟んで２５ＭＰａ（８ｋＮ）の垂直荷重を付与しながら印加電圧１０Ｖにて測定した場合の体積抵抗率が１.０×１０10Ω・ｃｍ以上であることが好ましい。 Other powder properties include a BET specific surface area of 30 to 100 m 2 / g, a TAP density of 0.8 to 1.5 g / cm 3 , a squareness ratio SQ of 0.3 to 0.6, and an SFD of 3.5 or less. Each is preferably in the range. Regarding the weather resistance, Δσs representing the rate of change in σs before and after the test in which the metal magnetic powder is kept in an air environment at a temperature of 60 ° C. and a relative humidity of 90% for one week is preferably 20% or less. Here, Δσs (%) is calculated by (σs before test−σs after test) / σs × 100 before test. For insulation, the volume when measured at an applied voltage of 10 V while applying a vertical load of 25 MPa (8 kN) by sandwiching 1.0 g of metal magnetic powder between the electrodes by a double ring electrode method according to JIS K6911. The resistivity is preferably 1.0 × 10 10 Ω · cm or more.
〔透磁率・誘電率〕
本発明に従う金属磁性粉末の交流磁気・誘電特性は、当該金属磁性粉末とエポキシ樹脂を９０：１０の質量割合で混合して作製した成形体の磁気特性によって評価される。この成形体による１ＧＨｚにおいて、複素比透磁率の実数部μ’が２.５０以上、かつ前記μ’と複素比誘電率の実数部ε’の比で表されるμ’／ε’比が０.２５以上となる性質を有する金属磁性粉末は、透磁率が高いため十分な小型化効果を発揮することができ、かつリターンロスの小さいアンテナの構築に極めて有用である。μ’／ε’比はできるだけ１.０に近い大きい値を示すことが望ましいが、通常、０.５０以下の範囲であれば十分であり、０.４０以下であっても構わない。
また、２ＧＨｚにおいて、複素比透磁率の実数部μ’が２.６０以上、かつ前記μ’と複素比誘電率の実数部ε’の比で表されるμ’／ε’比が０.２７以上となる性質を有することがより好ましい。さらに、３ＧＨｚにおいて、複素比透磁率の実数部μ’が２.７０以上、かつ前記μ’と複素比誘電率の実数部ε’の比で表されるμ’／ε’比が０.２８以上となる性質を有することがより好ましい。
磁気損失については、この成形体による１ＧＨｚのｔａｎδ（μ）が０.０５０以下であることが好ましく、０.０２０以下であることがより好ましい。また、２ＧＨｚのｔａｎδ（μ）が０.１０以下であることがより好ましく、３ＧＨｚのｔａｎδ（μ）が０.２０以下であることがさらに好ましい。これらのｔａｎδ（μ）は小さければ小さいほど好ましいが、通常０.００５以上の範囲で調整されていればよい。
[Permeability / dielectric constant]
The AC magnetic / dielectric properties of the metal magnetic powder according to the present invention are evaluated by the magnetic properties of a molded body prepared by mixing the metal magnetic powder and the epoxy resin at a mass ratio of 90:10. At 1 GHz with this molded body, the real part μ ′ of the complex relative permeability is 2.50 or more, and the μ ′ / ε ′ ratio expressed by the ratio of the μ ′ and the real part ε ′ of the complex relative permittivity is 0. A metal magnetic powder having a property of .25 or more has a high magnetic permeability, so that it can exhibit a sufficient miniaturization effect and is extremely useful for construction of an antenna with a small return loss. It is desirable that the μ ′ / ε ′ ratio be as large as possible as close to 1.0 as possible, but usually it is sufficient if it is in the range of 0.50 or less, and it may be 0.40 or less.
Further, at 2 GHz, the real part μ ′ of the complex relative permeability is 2.60 or more, and the μ ′ / ε ′ ratio expressed by the ratio of the μ ′ and the real part ε ′ of the complex relative permittivity is 0.27. It is more preferable to have the above properties. Further, at 3 GHz, the real part μ ′ of the complex relative permeability is 2.70 or more, and the μ ′ / ε ′ ratio expressed by the ratio of the μ ′ and the real part ε ′ of the complex relative permittivity is 0.28. It is more preferable to have the above properties.
Regarding the magnetic loss, the 1 GHz tan δ (μ) of the molded body is preferably 0.050 or less, and more preferably 0.020 or less. Further, tan δ (μ) at 2 GHz is more preferably 0.10 or less, and tan δ (μ) at 3 GHz is further preferably 0.20 or less. These tan δ (μ) are preferably as small as possible, but they may be adjusted in the range of usually 0.005 or more.
《製造方法》
リターンロスの低減および磁気損失の低減を上記のように高レベルで両立させることのできる金属磁性粉末は、以下のような工程で製造することができる。
〔前駆体形成工程〕
鉄イオンを含有する水溶液に酸化剤を導入してオキシ水酸化鉄の核晶を生成および成長させる。鉄イオンを含有する水溶液としては、水溶性の鉄化合物（硫酸鉄、硝酸鉄、塩化鉄など）を、水酸化アルカリ（ＮａＯＨ、ＫＯＨなど）水溶液や炭酸アルカリ（炭酸ナトリウム、炭酸アンモニウムなど）水溶液で中和して得られる２価のＦｅイオンを含む水溶液が好適である。酸化剤としては、空気などの酸素含有ガスや、過酸化水素などが使用できる。前記鉄イオンを含有する水溶液に酸素含有ガスを通気させるか、過酸化水素などの酸化剤物質を添加することにより、オキシ水酸化鉄の核晶を生成させる。その後、さらに酸化剤の導入を継続して、前記核晶の表面にオキシ水酸化鉄を析出させる。オキシ水酸化鉄粒子の成長が終了するまでの間に、水溶性のコバルト化合物を添加し、Ｆｅ、Ｃｏを含有する前駆体を形成する。水溶性のコバルト化合物としては、硫酸コバルト、硝酸コバルト、塩化コバルトなどが使用できる。コバルトの添加を開始する時期は、核晶の生成開始前（すなわち酸化剤の導入前）とすることが好ましい。この初期段階でコバルトの全量を添加してもよいし、核晶が生成したのちにコバルトを追加投入してもよい。添加方法は、一挙添加、分割添加、連続添加を適宜選択すればよい。
"Production method"
A metal magnetic powder capable of achieving both a reduction in return loss and a reduction in magnetic loss at a high level as described above can be produced by the following process.
[Precursor forming step]
An oxidizing agent is introduced into an aqueous solution containing iron ions to produce and grow iron oxyhydroxide nuclei. As an aqueous solution containing iron ions, a water-soluble iron compound (iron sulfate, iron nitrate, iron chloride, etc.) is used in an alkali hydroxide (NaOH, KOH, etc.) aqueous solution or an alkali carbonate (sodium carbonate, ammonium carbonate, etc.) aqueous solution. An aqueous solution containing divalent Fe ions obtained by neutralization is preferred. As the oxidizing agent, an oxygen-containing gas such as air, hydrogen peroxide, or the like can be used. An oxygen-containing gas is passed through the aqueous solution containing iron ions, or an oxidant substance such as hydrogen peroxide is added to produce iron oxyhydroxide nuclei. Thereafter, the introduction of an oxidizing agent is continued to deposit iron oxyhydroxide on the surface of the nuclei. Until the growth of the iron oxyhydroxide particles is completed, a water-soluble cobalt compound is added to form a precursor containing Fe and Co. As the water-soluble cobalt compound, cobalt sulfate, cobalt nitrate, cobalt chloride and the like can be used. The timing for starting the addition of cobalt is preferably before the start of nucleation generation (that is, before the introduction of the oxidizing agent). In this initial stage, the entire amount of cobalt may be added, or cobalt may be additionally charged after the nuclei are formed. As the addition method, one-time addition, divided addition, and continuous addition may be appropriately selected.
また、核晶の成長が終了するまでに、水溶性の希土類元素（Ｙも希土類元素として扱う）化合物、水溶性のアルミニウム化合物、水溶性のマグネシウム化合物の１種以上を添加して、Ｆｅ、Ｃｏを含有し、更に希土類元素、Ａｌ、Ｍｇの１種以上を含有する前駆体を得ることもできる。これらの添加方法は、一挙添加、分割添加、連続添加を適宜選択すればよい。水溶性の希土類元素化合物としては、例えばイットリウム化合物の場合、硫酸イットリウム、硝酸イットリウム、塩化イットリウムなどが挙げられる。水溶性のアルミニウム化合物としては、硫酸アルミニウム、塩化アルミニウム、硝酸アルミニウム、アルミン酸ナトリウム、アルミン酸カリウムなどが挙げられる。水溶性のマグネシウム化合物としては、硫酸マグネシウム、塩化マグネシウム、硝酸マグネシウムなどが挙げられる。これら添加元素を含有させる場合の含有量に関し、希土類元素／（Ｆｅ＋Ｃｏ）モル比は１０モル％以下の範囲とすることが好ましく、０.１〜５モル％の範囲に管理してもよい。Ａｌ／（Ｆｅ＋Ｃｏ）モル比は２０モル％以下の範囲とすることが好ましく、１〜１５モル％の範囲に管理してもよい。Ｍｇ／（Ｆｅ＋Ｃｏ）モル比は２０モル％以下の範囲とすることが好ましく、１〜１５モル％の範囲に管理してもよい。 Further, before the growth of the nucleus crystal is completed, at least one of a water-soluble rare earth element (Y is also treated as a rare earth element) compound, a water-soluble aluminum compound, and a water-soluble magnesium compound is added, and Fe, Co In addition, a precursor containing one or more of rare earth elements, Al, and Mg can also be obtained. These addition methods may be appropriately selected from one-time addition, divided addition, and continuous addition. Examples of the water-soluble rare earth element compound include yttrium sulfate, yttrium nitrate, and yttrium chloride in the case of an yttrium compound. Examples of the water-soluble aluminum compound include aluminum sulfate, aluminum chloride, aluminum nitrate, sodium aluminate, and potassium aluminate. Examples of the water-soluble magnesium compound include magnesium sulfate, magnesium chloride, and magnesium nitrate. Regarding the content when these additive elements are contained, the rare earth element / (Fe + Co) molar ratio is preferably in the range of 10 mol% or less, and may be controlled in the range of 0.1 to 5 mol%. The Al / (Fe + Co) molar ratio is preferably in the range of 20 mol% or less, and may be controlled in the range of 1 to 15 mol%. The Mg / (Fe + Co) molar ratio is preferably in the range of 20 mol% or less, and may be controlled in the range of 1 to 15 mol%.
必要に応じて、希土類元素（Ｙも希土類元素として扱う）が水溶液中に存在している状態で前記核晶を生成させることができる。核晶を生成する前に添加する希土類元素の添加量を変化させることで、得られる前駆体や最終的に得られる金属磁性粉末を構成する粒子の軸比を制御することができる。さらに、希土類元素（Ｙも希土類元素として扱う）、Ａｌ、Ｓｉ、Ｍｇの１種以上が水溶液中に存在している状態で前記析出成長を進行させることができる。 If necessary, the nuclei can be generated in the state where a rare earth element (Y is also treated as a rare earth element) is present in the aqueous solution. By changing the addition amount of the rare earth element added before the nucleation crystal is generated, the axial ratio of the particles constituting the obtained precursor and the finally obtained metal magnetic powder can be controlled. Furthermore, the above-described precipitation growth can be advanced in a state where one or more of rare earth elements (Y is also treated as a rare earth element), Al, Si, and Mg are present in the aqueous solution.
〔前駆体へのＳｉ被着工程〕
前記前駆体を含む水溶媒（スラリー）中に水溶性のケイ素化合物を添加して混合し、Ｓｉ元素を粒子表面に有する前駆体を得る。この表面処理された前駆体を本明細書では「Ｓｉ被着前駆体」と呼んでいる。水溶性のケイ素化合物としては、例えば珪酸ソーダが好適である。添加するケイ素化合物の量は、ＦｅとＣｏの総モル量に対しＳｉの量が１.０〜２０.０モル％となるように調整することが好ましい。ケイ素化合物が溶解したスラリーを撹拌する。撹拌時のスラリー温度は１０〜１００℃とすることが好ましく、撹拌時間は０.１〜２４ｈの範囲で設定すればよい。この撹拌混合により、前駆体の粒子表面にＳｉ含有物質が被着される。その後、濾過、水洗、乾燥の過程を経て、Ｓｉ被着前駆体が得られる。粒子表面に存在するＳｉの量（以下「Ｓｉ被着量」という）は、添加するケイ素化合物の量、スラリー温度、スラリーｐＨ、撹拌時間などによってコントロールできる。
なお、後述の「金属粉へのＳｉ被着工程」を実施する場合は、この「前駆体へのＳｉ被着工程」を省略することができる。
[Si deposition process to precursor]
A water-soluble silicon compound is added and mixed in an aqueous solvent (slurry) containing the precursor to obtain a precursor having Si elements on the particle surfaces. This surface treated precursor is referred to herein as a “Si deposition precursor”. As the water-soluble silicon compound, for example, sodium silicate is suitable. The amount of the silicon compound to be added is preferably adjusted so that the amount of Si is 1.0 to 20.0 mol% with respect to the total molar amount of Fe and Co. The slurry in which the silicon compound is dissolved is stirred. The slurry temperature during stirring is preferably 10 to 100 ° C., and the stirring time may be set in the range of 0.1 to 24 h. By this stirring and mixing, the Si-containing substance is deposited on the surface of the precursor particles. Then, Si deposition precursor is obtained through the process of filtration, water washing, and drying. The amount of Si present on the particle surface (hereinafter referred to as “Si deposition amount”) can be controlled by the amount of silicon compound to be added, slurry temperature, slurry pH, stirring time, and the like.
In addition, when implementing the below-mentioned "Si deposition process to metal powder", this "Si deposition process to a precursor" can be abbreviate | omitted.
〔還元工程〕
前駆体の乾燥物を還元性ガス雰囲気中で加熱することにより、Ｆｅ−Ｃｏ合金磁性相を持つ金属粉末を得る。還元性ガスとしては、代表的には水素ガスが挙げられる。加熱温度は２５０〜６５０℃の範囲とすることができ、５００〜６５０℃がより好ましい。加熱時間は１０〜１２０ｍｉｎの範囲で調整すればよい。前駆体として上記の「Ｓｉ被着前駆体」を使用した場合、この還元で得られた粉末を構成する粒子の表面にはＳｉ濃化層が形成されている。
[Reduction process]
The dried precursor is heated in a reducing gas atmosphere to obtain a metal powder having an Fe—Co alloy magnetic phase. A typical example of the reducing gas is hydrogen gas. The heating temperature can be in the range of 250 to 650 ° C, more preferably 500 to 650 ° C. The heating time may be adjusted in the range of 10 to 120 min. When the above-mentioned “Si deposition precursor” is used as the precursor, a Si concentrated layer is formed on the surface of the particles constituting the powder obtained by this reduction.
〔徐酸化工程〕
還元工程を終えた金属磁性粉末は、そのまま大気に曝すと急速に酸化するおそれがある。徐酸化工程は、急激な酸化を回避しながら粒子表面に酸化物被覆層を形成させる工程である。還元後の金属粉末が曝される雰囲気を不活性ガス雰囲気とし、当該雰囲気中の酸素濃度を増大させながら２０〜３００℃、より好ましくは５０〜３００℃で金属粉末粒子表層部の酸化反応を進行させる手法が採用できる。前駆体として上記の「Ｓｉ被着前駆体」を使用した場合、Ｓｉ酸化物を含む酸化物被覆層を有する粒子で構成される金属粉末が得られる。上記還元工程と同じ炉中で徐酸化工程を実施する場合は、還元工程を終了後、炉内の還元性ガスを不活性ガスで置換し、上記温度範囲において当該不活性ガス雰囲気中に酸素含有ガスを導入しながら粒子表層部の酸化反応を進行させるとよい。金属粉末を別の熱処理装置に移して徐酸化工程を実施してもよい。また、還元工程後に金属粉末をコンベア等で移動させながら連続的に徐酸化工程を実施することもできる。いずれの場合も、還元工程後に、金属粉末を大気に曝すことなく、徐酸化工程に移行させることが重要である。不活性ガスとしては、希ガスおよび窒素ガスから選ばれる１種以上のガス成分が適用できる。酸素含有ガスとしては、純酸素ガスや空気が使用できる。酸素含有ガスとともに、水蒸気を導入してもよい。水蒸気は酸化皮膜を緻密化させる効果がある。金属磁性粉末を３０〜３００℃好ましくは５０〜３００℃に保持するときの酸素濃度は、最終的には０.１〜２１体積％とする。酸素含有ガスの導入は、連続的または間欠的に行うことができる。徐酸化工程の初期の段階で、酸素濃度が１.０体積％以下である時間を５ｍｉｎ以上キープすることがより好ましい。
[Slow oxidation process]
The metal magnetic powder that has undergone the reduction process may be rapidly oxidized when exposed to the air as it is. The gradual oxidation step is a step of forming an oxide coating layer on the particle surface while avoiding rapid oxidation. The atmosphere to which the reduced metal powder is exposed is an inert gas atmosphere, and the oxidation reaction of the surface layer of the metal powder particles proceeds at 20 to 300 ° C., more preferably 50 to 300 ° C. while increasing the oxygen concentration in the atmosphere. Can be used. When the above-mentioned “Si deposition precursor” is used as a precursor, a metal powder composed of particles having an oxide coating layer containing Si oxide is obtained. When carrying out the gradual oxidation process in the same furnace as the above reduction process, after the reduction process is completed, the reducing gas in the furnace is replaced with an inert gas, and oxygen is contained in the inert gas atmosphere in the above temperature range. It is preferable to advance the oxidation reaction of the particle surface layer while introducing the gas. The slow oxidation process may be performed by transferring the metal powder to another heat treatment apparatus. Moreover, a slow oxidation process can also be continuously implemented, moving a metal powder with a conveyor etc. after a reduction process. In any case, it is important to shift the metal powder to the gradual oxidation step after the reduction step without exposing the metal powder to the atmosphere. As the inert gas, one or more gas components selected from a rare gas and a nitrogen gas can be applied. Pure oxygen gas or air can be used as the oxygen-containing gas. Steam may be introduced together with the oxygen-containing gas. Water vapor has the effect of densifying the oxide film. The oxygen concentration when the metal magnetic powder is kept at 30 to 300 ° C., preferably 50 to 300 ° C., is finally 0.1 to 21% by volume. The introduction of the oxygen-containing gas can be performed continuously or intermittently. More preferably, at the initial stage of the gradual oxidation step, the time during which the oxygen concentration is 1.0% by volume or less is kept for 5 minutes or more.
〔還元・徐酸化反復工程〕
上記の徐酸化工程を終えた金属粉末に対して、再度、還元処理および徐酸化処理を１回以上施す。具体的には、還元性ガス雰囲気中での２５０〜６５０℃の加熱処理と、それに続く前記徐酸化工程に従う処理を１回以上実施する。この還元・徐酸化反復工程が、本発明では極めて重要である。この工程を採用することによってリターンロスが小さく、かつ磁気損失の小さい金属磁性粉末を得ることが可能となる。そのメカニズムは上述のように推察される。還元・徐酸化反復工程での還元処理では、２５０〜６５０℃での保持時間を１０〜１２０ｍｉｎの範囲で設定すればよい。
[Reduction / Slow oxidation repeat process]
The reduction treatment and the gradual oxidation treatment are again performed once or more on the metal powder after the gradual oxidation step. Specifically, the heat treatment at 250 to 650 ° C. in a reducing gas atmosphere and the subsequent treatment according to the gradual oxidation step are carried out once or more. This repeated reduction / slow oxidation process is extremely important in the present invention. By adopting this process, it is possible to obtain a metal magnetic powder with a small return loss and a small magnetic loss. The mechanism is inferred as described above. In the reduction treatment in the reduction / slow oxidation repetitive step, the holding time at 250 to 650 ° C. may be set in the range of 10 to 120 min.
〔金属粉へのＳｉ被着工程〕
Ｓｉ含有物質の被着は、前駆体に還元処理および徐酸化処理を施して作製した金属磁性粉末に対して行うこともでき、前駆体に還元・徐酸化工程処理を施して作製した金属磁性粉末に、さらに還元処理および徐酸化処理を１回以上施すことにより作製した還元・徐酸化反復工程処理後の金属磁性粉末に対して行うこともできる。水などの溶媒中に金属磁性粉末を分散させて、水溶性のケイ素化合物を添加して混合し、その後、濾過、水洗、乾燥の過程を経ることにより、Ｓｉ被着金属磁性粉末が得られる。金属粉へのＳｉ被着工程におけるＳｉ被着量についても、前駆体へのＳｉ被着工程におけるＳｉ被着量と同様に、添加するケイ素化合物の量、スラリー温度、スラリーｐＨ、撹拌時間などによってコントロールできる。
[Si deposition process on metal powder]
The deposition of the Si-containing material can also be performed on the metal magnetic powder produced by subjecting the precursor to reduction treatment and gradual oxidation treatment, and the metal magnetic powder produced by subjecting the precursor to reduction / gradual oxidation treatment. Furthermore, it can also be performed on the metal magnetic powder after the reduction / gradual oxidation repetitive step treatment produced by performing the reduction treatment and the gradual oxidation treatment at least once. A metal magnetic powder is dispersed in a solvent such as water, a water-soluble silicon compound is added and mixed, and then a Si-coated metal magnetic powder is obtained through filtration, washing with water, and drying. Similarly to the Si deposition amount in the Si deposition step on the precursor, the Si deposition amount in the Si deposition step on the metal powder also depends on the amount of silicon compound to be added, slurry temperature, slurry pH, stirring time, etc. You can control.
《デバイス》
本発明に従う金属磁性粉末は、アンテナ、インダクタ、ＥＭＩフィルタ等のデバイス（電子部品）の構成材料として有用である。例えばアンテナを例に挙げると、導体板と、それに平行に配置される放射板とを有する平面アンテナへの適用が効果的である。当該金属磁性粉末は、平面アンテナに限らず種々の形状、構成のアンテナに使用できる。平面アンテナの構成は例えば特許文献３の図１に開示されている。平面アンテナの小型化手法の１つとして、導体板と放射板との間に高透磁率の磁性体を配置することが有効である。しかし、従来の磁性体は数百ＭＨｚ以上の高周波帯域における損失が大きいため、磁性体を用いるタイプの平面アンテナの普及は遅れている。本発明に従う金属磁性粉末は、４３０ＭＨｚ以上の電波を受信、送信、または送受信するアンテナ用の磁性体素材として極めて有用である。特に７００ＭＨｚ〜６ＧＨｚの周波数帯域で使用されるアンテナへの適用がより効果的である。
"device"
The metal magnetic powder according to the present invention is useful as a constituent material for devices (electronic parts) such as antennas, inductors, and EMI filters. For example, when an antenna is taken as an example, application to a planar antenna having a conductor plate and a radiation plate arranged in parallel thereto is effective. The metal magnetic powder can be used not only for planar antennas but also for antennas of various shapes and configurations. The configuration of the planar antenna is disclosed in FIG. As one of the miniaturization methods of the planar antenna, it is effective to arrange a magnetic material having a high permeability between the conductor plate and the radiation plate. However, since the conventional magnetic material has a large loss in a high frequency band of several hundred MHz or more, the spread of the planar antenna using the magnetic material is delayed. The metal magnetic powder according to the present invention is extremely useful as a magnetic material for an antenna that receives, transmits, or transmits / receives radio waves of 430 MHz or higher. In particular, application to antennas used in the frequency band of 700 MHz to 6 GHz is more effective.
本発明に従う金属磁性粉末を樹脂組成物と混合した成形体とし、これをアンテナ、インダクタ、ＥＭＩフィルタ等のデバイスを構成する磁性体に使用する。樹脂としては、公知の熱硬化性樹脂または熱可塑性樹脂を適用すればよい。例えば、熱硬化性樹脂としては、フェノール樹脂、エポキシ樹脂、不飽和ポリエステル樹脂、イソシアネート化合物、メラミン樹脂、尿素樹脂、シリコーン樹脂などから選択することができる。エポキシ樹脂としては、モノエポキシ化合物、多価エポキシ化合物のいずれか又はそれらの混合物を用いることができる。モノエポキシ化合物や、多価エポキシ化合物は、特許文献３に種々のものが例示されており、それらを適宜選択して使用することができる。熱可塑性樹脂としては、ポリ塩化ビニル樹脂、ＡＢＳ樹脂、ポリプロピレン樹脂、ポリエチレン樹脂、ポリスチレン樹脂、アクニロニトリルスチレン樹脂、アクリル樹脂、ポリエチレンテレフタレート樹脂、ポリフェニレンエーテル樹脂 、ポリサルフォン樹脂、ポリアリレート樹脂、ポリエーテルイミド樹脂、ポリエーテルエーテルケトン樹脂、ポリエーテルサルフォン樹脂、ポリアミド樹脂、ポリアミドイミド樹脂、ポリカーボネート樹脂、ポリアセタール樹脂、ポリブチレンテレフタレート樹脂、ポリフェニレンサルファイド樹脂、ポリエーテルエーテルケトン樹脂、ポリエーテルスルホン樹脂、液晶ポリマー（ＬＣＰ）、フッ素樹脂、ウレタン樹脂などから選択することができる。 The metal magnetic powder according to the present invention is mixed with a resin composition to form a molded body, which is used as a magnetic body constituting a device such as an antenna, an inductor, or an EMI filter. A known thermosetting resin or thermoplastic resin may be applied as the resin. For example, the thermosetting resin can be selected from phenol resin, epoxy resin, unsaturated polyester resin, isocyanate compound, melamine resin, urea resin, silicone resin, and the like. As the epoxy resin, either a monoepoxy compound, a polyvalent epoxy compound, or a mixture thereof can be used. Various monoepoxy compounds and polyvalent epoxy compounds are exemplified in Patent Document 3, and they can be appropriately selected and used. As thermoplastic resins, polyvinyl chloride resin, ABS resin, polypropylene resin, polyethylene resin, polystyrene resin, acrylonitrile styrene resin, acrylic resin, polyethylene terephthalate resin, polyphenylene ether resin, polysulfone resin, polyarylate resin, polyetherimide Resin, polyether ether ketone resin, polyether sulfone resin, polyamide resin, polyamide imide resin, polycarbonate resin, polyacetal resin, polybutylene terephthalate resin, polyphenylene sulfide resin, polyether ether ketone resin, polyether sulfone resin, liquid crystal polymer ( LCP), fluororesin, urethane resin and the like.
金属磁性粉末と樹脂の混合の割合は、金属磁性粉末／樹脂の質量比で表すと、３０／７０以上９９／１以下が好ましく、５０／５０以上９５／５以下がより好ましく、７０／３０以上９０／１０以下がさらに好ましい。樹脂が少なすぎると成形体にならず、多すぎると所望の磁気特性が得られない。 The mixing ratio of the metal magnetic powder and the resin is preferably 30/70 or more and 99/1 or less, more preferably 50/50 or more and 95/5 or less, and more preferably 70/30 or more when expressed by the mass ratio of the metal magnetic powder / resin. 90/10 or less is more preferable. If the amount of the resin is too small, the molded body is not formed.
《実施例１》
〔反応元液の作成〕
１ｍｏｌ／Ｌの硫酸第一鉄水溶液と１ｍｏｌ／Ｌの硫酸コバルト水溶液をＦｅ：Ｃｏのモル比が１００：１０となるように混合して約９００ｍＬの溶液とし、これに０.２ｍｏｌ／Ｌの硫酸イットリウム水溶液をＹ／（Ｆｅ＋Ｃｏ）モル比が２.６モル％となるように加えて、約１ＬのＦｅ、Ｃｏ、Ｙ含有溶液を用意した。５０００ｍＬビーカーに、純水２６００ｍＬと、前記Ｆｅ、Ｃｏ、Ｙ含有溶液中のＦｅ2+に対しＣＯ3 2-が３当量となる量の炭酸アンモニウムを含有する炭酸アンモニウム溶液３５０ｍＬを添加し、温調機で４０℃に維持しながら撹拌し、炭酸アンモニウム水溶液を得た。この炭酸アンモニウム水溶液中に前記Ｆｅ、Ｃｏ、Ｙ含有溶液を全量加え、反応元液とした。
Example 1
[Preparation of reaction source solution]
A 1 mol / L ferrous sulfate aqueous solution and a 1 mol / L cobalt sulfate aqueous solution were mixed so that the Fe: Co molar ratio was 100: 10 to obtain a solution of about 900 mL, and 0.2 mol / L sulfuric acid was added thereto. An aqueous yttrium solution was added so that the Y / (Fe + Co) molar ratio was 2.6 mol% to prepare an approximately 1 L Fe, Co, Y-containing solution. To a 5000 mL beaker, add 2600 mL of pure water and 350 mL of an ammonium carbonate solution containing ammonium carbonate in such an amount that CO 3 2− is 3 equivalents to Fe 2+ in the Fe, Co, Y-containing solution. The mixture was stirred while maintaining the temperature at 40 ° C. to obtain an aqueous ammonium carbonate solution. The total amount of the Fe, Co, and Y-containing solution was added to the aqueous ammonium carbonate solution to obtain a reaction source solution.
〔前駆体形成〕
上記の反応元液に３ｍｏｌ／ＬのＨ2Ｏ2水溶液を５ｍＬ添加しオキシ水酸化鉄の核晶を生成させた。その後、この液を６０℃に昇温し、反応元液中に存在していた全Ｆｅ2+の４０％が酸化するまで液中に空気を通気した。このときに必要な通気量は、予め予備実験により把握してある。その後、反応元液中のＦｅの総量に対しＣｏ／Ｆｅモル比が１５モル％となる量のＣｏを含有する１ｍｏｌ／Ｌの硫酸コバルト水溶液を追加で添加した。このように、核晶生成後、Ｆｅの酸化が完結する前の途中段階でＣｏを添加する操作を、以下において「Ｃｏ途中添加」という。Ｃｏ途中添加後、０.３ｍｏｌ／Ｌの硫酸アルミニウム水溶液を反応元液中のＦｅとＣｏの総量に対しＡｌ／（Ｆｅ＋Ｃｏ）モル比が５.８モル％となるように添加し、酸化が完結するまで（すなわち前駆体の形成反応が終了するまで）空気を通気した。このようにして前駆体含有スラリーを得た。
(Precursor formation)
5 mL of a 3 mol / L H 2 O 2 aqueous solution was added to the reaction source solution to produce iron oxyhydroxide nuclei. Thereafter, this liquid was heated to 60 ° C., and air was passed through the liquid until 40% of the total Fe 2+ present in the reaction source liquid was oxidized. The amount of ventilation required at this time is previously determined by preliminary experiments. Thereafter, a 1 mol / L cobalt sulfate aqueous solution containing Co in such an amount that the Co / Fe molar ratio was 15 mol% with respect to the total amount of Fe in the reaction source solution was added. In this way, the operation of adding Co in the middle stage after the nucleation and before the oxidation of Fe is completed is referred to as “Co intermediate addition”. After the intermediate addition of Co, an aqueous solution of 0.3 mol / L of aluminum sulfate was added so that the Al / (Fe + Co) molar ratio was 5.8 mol% with respect to the total amount of Fe and Co in the reaction source solution, and the oxidation was completed. Air was aerated until the reaction was completed (ie until the precursor formation reaction was completed). In this way, a precursor-containing slurry was obtained.
〔前駆体へのＳｉ被着処理〕
上記前駆体含有スラリーに、１.６ｍｏｌ／Ｌの珪酸ソーダ（ＪＩＳ規格３号のものを希釈して使用）を当該スラリー中のＦｅとＣｏの総量に対しＳｉ／（Ｆｅ＋Ｃｏ）モル比が５.０モル％となるように添加し、６０℃で１ｈ撹拌したのち、濾過、水洗、空気中１１０℃での乾燥を経て、Ｓｉ被着前駆体の乾燥物（粉末）を得た。
[Si deposition to precursor]
In the above precursor-containing slurry, 1.6 mol / L sodium silicate (diluted JIS standard 3) is used, and the Si / (Fe + Co) molar ratio is 5. with respect to the total amount of Fe and Co in the slurry. After adding at 0 mol% and stirring at 60 ° C. for 1 h, a dried Si powder precursor (powder) was obtained through filtration, washing with water and drying in air at 110 ° C.
〔還元処理〕
上記のＳｉ被着前駆体の乾燥物を通気可能なバケットに入れ、そのバケットを貫通型還元炉内に装入し、炉内に水素ガスを流しながら６３０℃で４０ｍｉｎ保持することにより還元処理を施した。
[Reduction treatment]
The dried material of the Si deposition precursor is put into a bucket that can be vented, the bucket is placed in a through-type reduction furnace, and a reduction treatment is performed by holding at 630 ° C. for 40 minutes while flowing hydrogen gas into the furnace. gave.
〔徐酸化処理〕
還元処理後、炉内の雰囲気ガスを水素から窒素に変換し、窒素ガスを流した状態で炉内温度を降温速度２０℃／ｍｉｎで８０℃まで低下させた。その後、徐酸化処理を行う初期のガスとして、窒素ガス／空気の体積割合が１２５／１となるように窒素ガスと空気を混合したガス（酸素濃度約０.１７体積％）を炉内に導入し、当該混合ガス雰囲気中で金属粉末粒子表層部の酸化反応を進行させた。初期の混合ガス導入開始後、約２０ｍｉｎ経過時点から徐々に空気の混合割合を増大させ、最終的に窒素ガス／空気の体積割合が２５／１となる混合ガス（酸素濃度約０.８０体積％）を炉内に連続的に導入した。徐酸化処理時間は４０ｍｉｎであり、その間、温度は８０℃に維持し、ガスの導入流量もほぼ一定に保った。
[Slow oxidation treatment]
After the reduction treatment, the atmospheric gas in the furnace was converted from hydrogen to nitrogen, and the temperature in the furnace was lowered to 80 ° C. at a temperature lowering rate of 20 ° C./min in a state where nitrogen gas was allowed to flow. Thereafter, a gas (oxygen concentration of about 0.17 vol%) in which nitrogen gas and air are mixed so that the volume ratio of nitrogen gas / air is 125/1 is introduced into the furnace as the initial gas for performing the gradual oxidation treatment. Then, the oxidation reaction of the surface part of the metal powder particles was advanced in the mixed gas atmosphere. After the start of the introduction of the mixed gas, the air mixing ratio is gradually increased from about 20 minutes, and finally the mixed gas (the oxygen concentration is about 0.80% by volume) in which the volume ratio of nitrogen gas / air becomes 25/1. ) Was continuously introduced into the furnace. The slow oxidation treatment time was 40 min. During that time, the temperature was maintained at 80 ° C., and the gas introduction flow rate was also kept substantially constant.
〔還元・徐酸化反復処理〕
上記徐酸化処理を終えたのち、炉内温度を再び上昇させ、上記還元処理と同様条件で２回目の還元処理を施し、その後、上記徐酸化処理と同様条件で２回目の徐酸化処理を施した。以上の工程により、金属磁性粉末の供試粉末を得た。
[Reduction / Slow oxidation repeated treatment]
After finishing the gradual oxidation treatment, the furnace temperature is raised again, and the second reduction treatment is performed under the same conditions as the reduction treatment, and then the second gradual oxidation treatment is performed under the same conditions as the gradual oxidation treatment. did. The test powder of metal magnetic powder was obtained by the above process.
〔粒子径〕
各供試粉末について、ＴＥＭ観察による上述の方法で平均長径（すなわち平均粒子径）、平均短径、平均軸比を求めた。結果を表１中に示す。
〔Ｓｉ含有量〕
供試粉末の組成分析を、Ｓｉについては重量法、その他の元素についてはＩＣＰ発光分析法により行った。分析組成を表１中に示す。
〔Ｓｉ酸化物〕
供試粉末におけるＳｉＯ2を主体とするＳｉ酸化物の存在については、透過型電子顕微鏡（ＴＥＭ）観察によるコントラストで判別できる。また、組成分析によってもＳｉ酸化物の存在を確認することができ、例えばＥＳＣＡ、ＴＥＭ−ＥＤＸ、ＸＰＳ、ＳＩＭＳなどの方法を挙げることができる。特に、ＥＳＣＡによれば粒子表面から深さ方向への組成の変化を確認することができ、Ｓｉ酸化物被覆層を判別することができる。また、ＴＥＭ−ＥＤＸによれば粒子にビームを絞ってＥＤＸを照射し、半定量することにより、粒子の大体の組成を確認でき、Ｓｉ酸化物被覆層を判別することができる。Ｓｉ被着処理で被着させたＳｉは、Ｓｉ酸化物として酸化物被覆層を構成しているものと考えられる（前駆体へのＳｉ被着処理を行った以下の各例において同じ）。
〔Particle size〕
For each sample powder, the average major axis (that is, the average particle diameter), the average minor axis, and the average axial ratio were determined by the above-described method by TEM observation. The results are shown in Table 1.
[Si content]
The composition of the sample powder was analyzed by a gravimetric method for Si and by ICP emission analysis for other elements. The analytical composition is shown in Table 1.
[Si oxide]
The presence of Si oxide mainly composed of SiO 2 in the test powder can be determined by contrast by observation with a transmission electron microscope (TEM). The presence of Si oxide can also be confirmed by composition analysis, and examples thereof include ESCA, TEM-EDX, XPS, SIMS, and the like. In particular, according to ESCA, a change in composition from the particle surface in the depth direction can be confirmed, and the Si oxide coating layer can be identified. Further, according to TEM-EDX, the particle is focused to irradiate EDX, and semi-quantified, whereby the rough composition of the particle can be confirmed and the Si oxide coating layer can be discriminated. It is considered that Si deposited by the Si deposition process constitutes an oxide coating layer as a Si oxide (the same applies to the following examples in which the Si deposition process is performed on the precursor).
〔透磁率・誘電率〕
供試粉末とビスフェノールＦ型エポキシ樹脂（株式会社テスク製；一液性エポキシ樹脂Ｂ−１１０６）を９０：１０の質量割合で秤量し、真空撹拌・脱泡ミキサー（ＥＭＥ社製；Ｖ−ｍｉｎｉ３００）を用いてこれらを混練し、供試粉末がエポキシ樹脂中に分散したペーストとした。このペーストをホットプレート上で６０℃、２ｈ乾燥させて金属粉末と樹脂の複合体としたのち、粉末状に解粒して、複合体粉末とした。この複合体粉末０.２ｇをドーナッツ状の容器内に入れて、ハンドプレス機により９８００Ｎ（１Ｔｏｎ）の荷重をかけることにより、外径７ｍｍ、内径３ｍｍのトロイダル形状の成形体を得た。この成形体について、ネットワーク・アナライザー（アジレント・テクノロジー社製；Ｅ５０７１Ｃ）と同軸型Ｓパラメーター法サンプルホルダーキット（関東電子応用開発社製；ＣＳＨ２−ＡＰＣ７、試料寸法：φ７.０ｍｍ−φ３.０４ｍｍ×５ｍｍ）を用い、０.１〜４.５ＧＨｚにおける複素比透磁率の実数部μ’および虚数部μ”、並びに複素比誘電率の実数部ε’および虚数部ε”を測定し、μ’／ε’比、複素比透磁率の損失係数ｔａｎδ（μ）＝μ”／μ’および複素比誘電率の損失係数ｔａｎδ（ε）＝ε”／ε’を求めた。表３〜表５に、１ＧＨｚ、２ＧＨｚおよび３ＧＨｚにおけるこれらの結果を例示する（以下の各例において同じ）。本例では、μ’が大きく、μ’／ε’比が高く、かつｔａｎδ（μ）が低いという磁気特性・誘電特性を呈し、リターンロスおよび磁気損失の両方を改善することができた。
[Permeability / dielectric constant]
The test powder and bisphenol F type epoxy resin (manufactured by Tesque, Inc .; one-component epoxy resin B-1106) are weighed at a mass ratio of 90:10, and a vacuum agitation / defoaming mixer (manufactured by EME; V-mini300). These were kneaded using a paste to obtain a paste in which the test powder was dispersed in an epoxy resin. This paste was dried on a hot plate at 60 ° C. for 2 hours to form a composite of metal powder and resin, and then pulverized into a powder form to obtain a composite powder. By putting 0.2 g of this composite powder in a donut-shaped container and applying a load of 9800 N (1 Ton) with a hand press machine, a toroidal shaped body having an outer diameter of 7 mm and an inner diameter of 3 mm was obtained. About this molded body, a network analyzer (manufactured by Agilent Technologies; E5071C) and a coaxial S-parameter method sample holder kit (manufactured by Kanto Electronics Application Development Co., Ltd .; CSH2-APC7, sample dimensions: φ7.0 mm-φ3.04 mm × 5 mm) ) To measure the real part μ ′ and imaginary part μ ″ of the complex relative permeability at 0.1 to 4.5 GHz, and the real part ε ′ and imaginary part ε ″ of the complex relative permittivity, and μ ′ / ε The loss factor tan δ (μ) = μ ″ / μ ′ of the ratio and complex relative permeability and the loss coefficient tan δ (ε) = ε ″ / ε ′ of the complex relative permittivity were determined. Tables 3 to 5 illustrate these results at 1 GHz, 2 GHz, and 3 GHz (same in each example below). In this example, μ ′ was large, μ ′ / ε ′ ratio was high, and tan δ (μ) was low, and magnetic characteristics and dielectric characteristics were exhibited, and both return loss and magnetic loss could be improved.
〔体積抵抗率〕
供試粉末の体積抵抗率は、ＪＩＳ Ｋ６９１１に準拠した二重リング電極方法により、供試粉末１.０ｇを電極間に挟んで１３〜６４ＭＰａ（４〜２０ｋＮ）の垂直荷重を付与しながら印加電圧１０Ｖにて測定する方法により求めた。測定には、三菱化学アナリテック社製粉体抵抗測定ユニット（ＭＣＰ―ＰＤ５１）、同社製高抵抗抵抗率計ハイレスタＵＰ（ＭＣＰ−ＨＴ４５０）、同社製高抵抗粉体測定システムソフトウェアを用いた。表２中に結果を示す。本例では、荷重２５ＭＰａ（８ｋＮ）での体積抵抗率が１.０×１０8Ω・ｃｍ以上であり、良好な絶縁性を有していた。
[Volume resistivity]
The volume resistivity of the test powder was determined by applying a vertical load of 13 to 64 MPa (4 to 20 kN) with 1.0 g of the test powder sandwiched between the electrodes by a double ring electrode method according to JIS K6911. It calculated | required by the method of measuring at 10V. For the measurement, a powder resistance measurement unit (MCP-PD51) manufactured by Mitsubishi Chemical Analytech, a high resistance resistivity meter Hiresta UP (MCP-HT450) manufactured by Mitsubishi Chemical, and a high resistance powder measurement system software manufactured by the company were used. Table 2 shows the results. In this example, the volume resistivity at a load of 25 MPa (8 kN) was 1.0 × 10 8 Ω · cm or more, and it had good insulating properties.
〔ＢＥＴ比表面積〕
ＢＥＴ比表面積は、ユアサアイオニクス社製の４ソーブＵＳを用いて、ＢＥＴ一点法により求めた。
〔ＴＡＰ密度〕
ＴＡＰ密度は、ガラス製のサンプルセル（５ｍｍ径×４０ｍｍ高さ）に供試粉末を入れ、タップ高さ１０ｃｍとして、２００回タッピングを行って測定した。
[BET specific surface area]
The BET specific surface area was determined by the BET single point method using 4 Sorb US manufactured by Yuasa Ionics.
[TAP density]
The TAP density was measured by putting the test powder in a glass sample cell (5 mm diameter × 40 mm height) and tapping 200 times with a tap height of 10 cm.
〔粉末の磁気特性および耐候性〕
供試粉末の磁気特性（バルク特性）として、ＶＳＭ装置（東英工業社製；ＶＳＭ−７Ｐ）を使用して、外部磁場７９５.８ｋＡ／ｍ（１０ｋＯｅ）で、保磁力Ｈｃ（ｋＡ／ｍ）、飽和磁化σｓ（Ａｍ2／ｋｇ）、角形比ＳＱを測定した。耐候性については、金属磁性粉末を温度６０℃、相対湿度９０％の空気環境に１週間保持する試験前後のσｓの変化量率Δσｓにより評価した。Δσｓは（試験前のσｓ−試験後のσｓ）／試験前のσｓ×１００によって算出される。これらの結果を表２中に示す。本例では、Ｈｃが７９.６ｋＡ／ｍ以下、σｓが１４７Ａｍ2／ｋｇ以上であり、アンテナ用素材として好適な磁気特性を有していた。耐候性も良好であった。
[Magnetic properties and weather resistance of powder]
As a magnetic property (bulk property) of the test powder, using a VSM apparatus (manufactured by Toei Kogyo Co., Ltd .; VSM-7P), an external magnetic field of 795.8 kA / m (10 kOe) and a coercive force Hc (kA / m) The saturation magnetization σs (Am 2 / kg) and the squareness ratio SQ were measured. The weather resistance was evaluated by the change rate Δσs of σs before and after the test in which the metal magnetic powder was kept in an air environment at a temperature of 60 ° C. and a relative humidity of 90% for 1 week. Δσs is calculated by (σs before test−σs after test) / σs × 100 before test. These results are shown in Table 2. In this example, Hc was 79.6 kA / m or less, and σs was 147 Am 2 / kg or more, which had magnetic characteristics suitable as an antenna material. The weather resistance was also good.
《実施例２、３》
前駆体へのＳｉ被着処理において、珪酸ソーダの添加量をスラリー中のＦｅとＣｏの総量に対しＳｉ／（Ｆｅ＋Ｃｏ）モル比が１０.０モル％（実施例２）および１５.０モル％（実施例３）としたことを除き、実施例１と同様の条件で実験を行った。表２〜表５に示すように、これらの例では実施例１と同様に各特性において良好な結果が得られた。
<< Examples 2 and 3 >>
In the Si deposition treatment on the precursor, the amount of sodium silicate added was 10.0 mol% (Example 2) and 15.0 mol% with respect to the total amount of Fe and Co in the slurry. The experiment was performed under the same conditions as in Example 1 except that (Example 3) was used. As shown in Tables 2 to 5, in these examples, good results were obtained in each characteristic as in Example 1.
《比較例１》
前駆体へのＳｉ被着処理を行わなかったこと、および還元・徐酸化処理を１回のみとし還元・徐酸化反復処理を行わなかったことを除き、実施例１と同様の条件で実験を行った。表１、表２に示すように、本例ではσｓが高いにもかかわらず、μ’／ε’比が低くなり、リターンロスの改善が不十分であった。
<< Comparative Example 1 >>
The experiment was performed under the same conditions as in Example 1 except that the Si deposition treatment on the precursor was not performed and that the reduction / gradual oxidation treatment was performed only once and no reduction / gradual oxidation treatment was performed. It was. As shown in Tables 1 and 2, in this example, although the σs was high, the μ ′ / ε ′ ratio was low, and the return loss was insufficiently improved.
《比較例２〜４》
還元・徐酸化処理を１回のみとし還元・徐酸化反復処理を行わなかったことを除き、比較例２、３および４はそれぞれ実施例１、２および３と同様の条件で実験を行った。表２〜表５に示すように、これらの例ではσｓが低く、比較例２はμ’／ε’比が低くなり、比較例３、４ではμ’値が低かった。
<< Comparative Examples 2-4 >>
Comparative Examples 2, 3 and 4 were tested under the same conditions as in Examples 1, 2 and 3, except that the reduction / gradual oxidation treatment was performed only once and the reduction / gradual oxidation repeated treatment was not performed. As shown in Tables 2 to 5, in these examples, σs was low, Comparative Example 2 had a low μ ′ / ε ′ ratio, and Comparative Examples 3 and 4 had a low μ ′ value.
《比較例５》
前駆体へのＳｉ被着処理を行わなかったことを除き、実施例１と同様の条件で実験を行った。表１、表２に示すように、本例ではσｓが高いにもかかわらず、μ’／ε’比が低くなり、リターンロスの改善が不十分であった。
<< Comparative Example 5 >>
The experiment was performed under the same conditions as in Example 1 except that the Si deposition treatment on the precursor was not performed. As shown in Tables 1 and 2, in this example, although the σs was high, the μ ′ / ε ′ ratio was low, and the return loss was insufficiently improved.
《実施例４》
Ｃｏ途中添加を行わず、Ｃｏ／Ｆｅ比を１０モル％としたことを除き、実施例１と同様の条件で実験を行った。表２〜表５に示すように、本例では実施例１と同様に各特性において良好な結果が得られた。
Example 4
The experiment was performed under the same conditions as in Example 1 except that Co was not added in the middle and the Co / Fe ratio was 10 mol%. As shown in Tables 2 to 5, in this example, good results were obtained in each characteristic as in Example 1.
《比較例６》
前駆体へのＳｉ被着処理を行わなかったこと、および還元・徐酸化処理を１回のみとし還元・徐酸化反復処理を行わなかったことを除き、実施例４と同様の条件で実験を行った。表２〜表５に示すように、本例ではσｓが高いにもかかわらず、μ’／ε’比が低くなり、リターンロスの改善が不十分であった。
<< Comparative Example 6 >>
The experiment was performed under the same conditions as in Example 4 except that the Si deposition treatment on the precursor was not performed and that the reduction / gradual oxidation treatment was performed only once and the reduction / gradual oxidation repeated treatment was not performed. It was. As shown in Tables 2 to 5, in this example, although the σs was high, the μ ′ / ε ′ ratio was low, and the return loss was insufficiently improved.
《比較例７》
前駆体へのＳｉ被着処理を行わなかったことを除き、実施例４と同様の条件で実験を行った。表２〜表５に示すように、本例ではσｓが高いにもかかわらず、μ’／ε’比が低くなり、リターンロスの改善が不十分であった。
<< Comparative Example 7 >>
An experiment was performed under the same conditions as in Example 4 except that the Si deposition treatment on the precursor was not performed. As shown in Tables 2 to 5, in this example, although the σs was high, the μ ′ / ε ′ ratio was low, and the return loss was insufficiently improved.
《比較例８》
還元・徐酸化処理を１回のみとし還元・徐酸化反復処理を行わなかったことを除き、実施例４と同様の条件で実験を行った。表２〜表５に示すように、本例ではσｓが低く、μ’／ε’比が低くなり、μ’値そのものも低かった。
<< Comparative Example 8 >>
The experiment was performed under the same conditions as in Example 4 except that the reduction / gradual oxidation treatment was performed only once and the reduction / gradual oxidation repeated treatment was not performed. As shown in Tables 2 to 5, in this example, σs was low, the μ ′ / ε ′ ratio was low, and the μ ′ value itself was also low.
《実施例５》
〔反応元液の作成〕
１ｍｏｌ／Ｌの硫酸第一鉄水溶液と１ｍｏｌ／Ｌの硫酸コバルト水溶液をＦｅ：Ｃｏのモル比が１００：１０となるように混合して約９００ｍＬの溶液とし、これに０.２ｍｏｌ／Ｌの硫酸イットリウム水溶液をＹ／（Ｆｅ＋Ｃｏ）モル比が２.６モル％となるように加えて、約１ＬのＦｅ、Ｃｏ、Ｙ含有溶液を用意した。５０００ｍＬビーカーに、純水２６００ｍＬと、前記Ｆｅ、Ｃｏ、Ｙ含有溶液中のＦｅ2+に対しＣＯ3 2-が３当量となる量の炭酸アンモニウムを含有する炭酸アンモニウム溶液３５０ｍＬを添加し、温調機で４０℃に維持しながら撹拌し、炭酸アンモニウム水溶液を得た。この炭酸アンモニウム水溶液中に前記Ｆｅ、Ｃｏ、Ｙ含有溶液を全量加え、反応元液とした。
Example 5
[Preparation of reaction source solution]
A 1 mol / L ferrous sulfate aqueous solution and a 1 mol / L cobalt sulfate aqueous solution were mixed so that the Fe: Co molar ratio was 100: 10 to obtain a solution of about 900 mL, and 0.2 mol / L sulfuric acid was added thereto. An aqueous yttrium solution was added so that the Y / (Fe + Co) molar ratio was 2.6 mol% to prepare an approximately 1 L Fe, Co, Y-containing solution. To a 5000 mL beaker, add 2600 mL of pure water and 350 mL of an ammonium carbonate solution containing ammonium carbonate in such an amount that CO 3 2− is 3 equivalents to Fe 2+ in the Fe, Co, Y-containing solution. The mixture was stirred while maintaining the temperature at 40 ° C. to obtain an aqueous ammonium carbonate solution. The total amount of the Fe, Co, and Y-containing solution was added to the aqueous ammonium carbonate solution to obtain a reaction source solution.
〔前駆体形成〕
上記の反応元液に３ｍｏｌ／ＬのＨ2Ｏ2水溶液を５ｍＬ添加しオキシ水酸化鉄の核晶を生成させた。その後、この液を６０℃に昇温し、反応元液中に存在していた全Ｆｅ2+の４０％が酸化するまで液中に空気を通気した。このときに必要な通気量は、予め予備実験により把握してある。その後、反応元液中のＦｅの総量に対しＣｏ／Ｆｅモル比が２５モル％となる量のＣｏを含有する１ｍｏｌ／Ｌの硫酸コバルト水溶液を追加で添加した。Ｃｏ途中添加後、０.３ｍｏｌ／Ｌの硫酸アルミニウム水溶液を反応元液中のＦｅとＣｏの総量に対しＡｌ／（Ｆｅ＋Ｃｏ）モル比が５.８モル％となるように添加し、酸化が完結するまで（すなわち前駆体の形成反応が終了するまで）空気を通気した。このようにして前駆体含有スラリーを得た。前駆体スラリー、濾過、水洗、空気中１１０℃での乾燥を経て、前駆体の乾燥物（粉末）を得た。
(Precursor formation)
5 mL of a 3 mol / L H 2 O 2 aqueous solution was added to the reaction source solution to produce iron oxyhydroxide nuclei. Thereafter, this liquid was heated to 60 ° C., and air was passed through the liquid until 40% of the total Fe 2+ present in the reaction source liquid was oxidized. The amount of ventilation required at this time is previously determined by preliminary experiments. Thereafter, a 1 mol / L cobalt sulfate aqueous solution containing Co in such an amount that the Co / Fe molar ratio was 25 mol% with respect to the total amount of Fe in the reaction source solution was added. After the intermediate addition of Co, an aqueous solution of 0.3 mol / L of aluminum sulfate was added so that the Al / (Fe + Co) molar ratio was 5.8 mol% with respect to the total amount of Fe and Co in the reaction source solution, and the oxidation was completed. Air was aerated until the reaction was completed (ie until the precursor formation reaction was completed). In this way, a precursor-containing slurry was obtained. A precursor dried product (powder) was obtained through precursor slurry, filtration, washing with water, and drying at 110 ° C. in air.
〔還元処理〕
上記の前駆体の乾燥物を通気可能なバケットに入れ、そのバケットを貫通型還元炉内に装入し、炉内に水素ガスを流しながら６３０℃で４０ｍｉｎ保持することにより還元処理を施した。
[Reduction treatment]
The dried product of the precursor was put in a bucket that can be ventilated, and the bucket was placed in a through-type reduction furnace, and reduced at 40 ° C. for 40 minutes while flowing hydrogen gas into the furnace.
〔徐酸化処理〕
還元処理後、炉内の雰囲気ガスを水素から窒素に変換し、窒素ガスを流した状態で炉内温度を降温速度２０℃／ｍｉｎで８０℃まで低下させた。その後、徐酸化処理を行う初期のガスとして、窒素ガス／空気の体積割合が１２５／１となるように窒素ガスと空気を混合したガス（酸素濃度約０.１７体積％）を炉内に導入し、当該混合ガス雰囲気中で金属粉末粒子表層部の酸化反応を進行させた。初期の混合ガス導入開始後、約２０ｍｉｎ経過時点から徐々に空気の混合割合を増大させ、最終的に窒素ガス／空気の体積割合が２５／１となる混合ガス（酸素濃度約０.８０体積％）を炉内に連続的に導入した。徐酸化処理時間は４０ｍｉｎであり、その間、温度は８０℃に維持し、ガスの導入流量もほぼ一定に保った。
[Slow oxidation treatment]
After the reduction treatment, the atmospheric gas in the furnace was converted from hydrogen to nitrogen, and the temperature in the furnace was lowered to 80 ° C. at a temperature lowering rate of 20 ° C./min in a state where nitrogen gas was allowed to flow. Thereafter, a gas (oxygen concentration of about 0.17 vol%) in which nitrogen gas and air are mixed so that the volume ratio of nitrogen gas / air is 125/1 is introduced into the furnace as the initial gas for performing the gradual oxidation treatment. Then, the oxidation reaction of the surface part of the metal powder particles was advanced in the mixed gas atmosphere. After the start of the introduction of the mixed gas, the air mixing ratio is gradually increased from about 20 minutes, and finally the mixed gas (the oxygen concentration is about 0.80% by volume) in which the volume ratio of nitrogen gas / air becomes 25/1. ) Was continuously introduced into the furnace. The slow oxidation treatment time was 40 min. During that time, the temperature was maintained at 80 ° C., and the gas introduction flow rate was also kept substantially constant.
〔還元・徐酸化反復処理〕
上記徐酸化処理を終えたのち、炉内温度を再び上昇させ、上記還元処理と同様条件で２回目の還元処理を施し、その後、上記徐酸化処理と同様条件で２回目の徐酸化処理を施した。以上の工程により、金属磁性粉末の供試粉末を得た。
[Reduction / Slow oxidation repeated treatment]
After finishing the gradual oxidation treatment, the furnace temperature is raised again, and the second reduction treatment is performed under the same conditions as the reduction treatment, and then the second gradual oxidation treatment is performed under the same conditions as the gradual oxidation treatment. did. The test powder of metal magnetic powder was obtained by the above process.
〔金属粉へのＳｉ被着〕
５０００ｍＬビーカーに、純水４５００ｍＬと上記の金属磁性粉末３００ｇを添加し、温調機で６０℃に維持しながら撹拌し、次いで１.６ｍｏｌ／Ｌの珪酸ソーダ（ＪＩＳ規格３号のものを希釈して使用）を当該スラリー中のＦｅとＣｏの総量に対しＳｉ／（Ｆｅ＋Ｃｏ）モル比が５.０モル％となるように添加し、３０℃で１ｈ撹拌したのち、濾過、水洗、空気中１１０℃での乾燥を経て、Ｓｉ被着金属磁性粉末の乾燥物（粉末）の供試粉体を得た。
得られた供試粉体について、実施例１と同様の手法で各測定を行った。表２〜表５に示すように、本例では実施例１と同様に各特性において良好な結果が得られた。
[Si deposition on metal powder]
Add 4500 mL of pure water and 300 g of the above metal magnetic powder to a 5000 mL beaker, stir while maintaining the temperature at 60 ° C. with a temperature controller, and then dilute 1.6 mol / L sodium silicate (JIS standard 3) Used) so that the Si / (Fe + Co) molar ratio becomes 5.0 mol% with respect to the total amount of Fe and Co in the slurry, and after stirring at 30 ° C. for 1 h, filtration, washing with water, and 110 in air After drying at ° C., a test powder of a dried product (powder) of the Si-coated metal magnetic powder was obtained.
The obtained sample powder was measured in the same manner as in Example 1. As shown in Tables 2 to 5, in this example, good results were obtained in each characteristic as in Example 1.
《実施例６》
Ｃｏ／Ｆｅ比を２０モル％とし、硫酸アルミニウム水溶液の添加量をスラリー中のＦｅとＣｏの総量に対しＡｌ／（Ｆｅ＋Ｃｏ）モル比が１５.０モル％となるように添加したことを除き、実施例４と同様の条件で実験を行った。表２〜表５に示すように、本例では実施例１と同様に各特性において良好な結果が得られた。
Example 6
Except that the Co / Fe ratio was 20 mol%, and the addition amount of the aluminum sulfate aqueous solution was added so that the Al / (Fe + Co) molar ratio was 15.0 mol% with respect to the total amount of Fe and Co in the slurry, The experiment was performed under the same conditions as in Example 4. As shown in Tables 2 to 5, in this example, good results were obtained in each characteristic as in Example 1.
《比較例９》
還元・徐酸化処理を１回のみとし還元・徐酸化反復処理を行わなかったことを除き、実施例６と同様の条件で実験を行った。表２〜表５に示すように、本例ではμ’／ε’比が低くなり、μ’値そのものも低かった。
<< Comparative Example 9 >>
The experiment was performed under the same conditions as in Example 6 except that the reduction / gradual oxidation treatment was performed only once and the reduction / gradual oxidation repeated treatment was not performed. As shown in Tables 2 to 5, in this example, the μ ′ / ε ′ ratio was low, and the μ ′ value itself was also low.
Claims (13)
前記前駆体を含む水溶媒中に水溶性のケイ素化合物を添加して混合し、Ｓｉ含有物質を被着した前駆体（以下「Ｓｉ被着前駆体」という）を得る工程（前駆体へのＳｉ被着工程）、
Ｓｉ被着前駆体の乾燥物を還元性ガス雰囲気中で２５０〜６５０℃に加熱することにより、Ｆｅ−Ｃｏ合金磁性相を持つ金属粉末を得る工程（還元工程）、
還元後の金属粉末を酸化雰囲気中２０〜３００℃に保持して金属粉末粒子表層部の酸化反応を進行させ、Ｓｉ酸化物を含む酸化物被覆層を有する粒子で構成される金属粉末を得る工程（徐酸化工程）、
Ｓｉ酸化物を含む酸化物被覆層を有する粒子で構成される金属粉末に対して、還元性ガス雰囲気中での２５０〜６５０℃の加熱処理と、それに続く前記徐酸化工程に従う処理を１回以上実施する工程（還元・徐酸化反復工程）、
を有する金属磁性粉末の製造方法。 Introducing an oxidant into an aqueous solution containing Fe ions and Co ions to precipitate and grow a precursor having Fe and Co as components (precursor forming step);
A step of adding a water-soluble silicon compound to an aqueous solvent containing the precursor and mixing to obtain a precursor having a Si-containing material deposited thereon (hereinafter referred to as “Si deposition precursor”) (Si to the precursor) Deposition process),
A step of obtaining a metal powder having a Fe—Co alloy magnetic phase by heating the dried Si deposition precursor to 250 to 650 ° C. in a reducing gas atmosphere (reduction step);
The process of obtaining the metal powder comprised by the particle | grains which hold | maintain the metal powder after reduction | restoration in 20-300 degreeC in oxidizing atmosphere, and advance the oxidation reaction of a metal powder particle surface layer part, and have an oxide coating layer containing Si oxide (Slow oxidation process),
One or more times of heat treatment at 250 to 650 ° C. in a reducing gas atmosphere and subsequent treatment according to the gradual oxidation step on the metal powder composed of particles having an oxide coating layer containing Si oxide Steps to be performed (reduction / gradual oxidation repeated step),
The manufacturing method of the metal magnetic powder which has this.
前駆体の乾燥物を還元性ガス雰囲気中で２５０〜６５０℃に加熱することにより、Ｆｅ−Ｃｏ合金磁性相を持つ金属粉末を得る工程（還元工程）、
還元後の金属粉末を酸化雰囲気中２０〜３００℃に保持して金属粉末粒子表層部の酸化反応を進行させ、酸化物被覆層を有する粒子で構成される金属粉末を得る工程（徐酸化工程）、
前記酸化物被覆層を有する粒子で構成される金属粉末に対して、還元性ガス雰囲気中での２５０〜６５０℃の加熱処理と、それに続く前記徐酸化工程に従う処理を１回以上実施する工程（還元・徐酸化反復工程）、
還元・徐酸化反復工程後の金属粉末と水溶性のケイ素化合物を水溶媒中で混合することにより、粉末粒子表面にＳｉ含有物質を被着させる工程（金属粉へのＳｉ被着工程）
を有する金属磁性粉末の製造方法。 Introducing an oxidant into an aqueous solution containing Fe ions and Co ions to precipitate and grow a precursor having Fe and Co as components (precursor forming step);
A step of obtaining a metal powder having an Fe—Co alloy magnetic phase by heating the dried precursor to 250 to 650 ° C. in a reducing gas atmosphere (reduction step);
The process of obtaining the metal powder comprised by the particle | grains which have an oxide coating layer by advancing the oxidation reaction of the metal powder particle | grain surface layer part by hold | maintaining the metal powder after reduction | restoration at 20-300 degreeC in oxidizing atmosphere (gradual oxidation process) ,
A step of performing at least one heat treatment at 250 to 650 ° C. in a reducing gas atmosphere and subsequent treatment according to the gradual oxidation step on the metal powder composed of particles having the oxide coating layer ( Reduction / slow oxidation repeated process),
A process of depositing a Si-containing substance on the surface of powder particles by mixing the metal powder and water-soluble silicon compound after the reduction and slow oxidation repeated processes in an aqueous solvent (Si deposition process on metal powder)
The manufacturing method of the metal magnetic powder which has this.
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