JP2012017251A - MnZnAlCo-BASED FERRITE - Google Patents
MnZnAlCo-BASED FERRITE Download PDFInfo
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本発明は、数十ｋＨｚ〜数十ＭＨｚの高周波帯域で使用される表面実装パワーインダクタなどに好適に用いられるＭｎＺｎＡｌＣｏ系フェライトに関し、特に初透磁率μｉおよび飽和磁束密度Ｂｓが高く、比抵抗が１０４Ωｍ以上であり、１０ｋＨｚ〜１ＭＨｚまでのμｉが平坦な周波数特性を有する高抵抗高飽和磁束密度のＭｎＺｎＡｌＣｏ系フェライトに関する。 The present invention relates to a MnZnAlCo-based ferrite suitably used for a surface mount power inductor used in a high frequency band of several tens of kHz to several tens of MHz, and particularly has a high initial magnetic permeability μi and a saturation magnetic flux density Bs and a specific resistance of 10 The present invention relates to a MnZnAlCo ferrite having a high resistance and a high saturation magnetic flux density of 4 Ωm or more and having a frequency characteristic in which μi from 10 kHz to 1 MHz is flat.
表面実装パワーインダクタ用磁芯としては、従来から、電気抵抗の高いＮｉＺｎ系フェライトの低背型ドラムコアが広く用いられている。しかし、近年のＣＰＵ駆動電圧低下に伴う大電流化の進展により、飽和磁束密度Ｂｓが低いＮｉＺｎ系フェライトでは、磁気飽和を起こし易いという問題が生じている。そのため、ＮｉＺｎ系フェライトをよりＢｓの高いＭｎＺｎ系フェライトへ置き換えることが検討されている。 As a surface mount power inductor magnetic core, a low profile drum core of NiZn ferrite having a high electric resistance has been widely used. However, due to the recent increase in current accompanying the decrease in CPU drive voltage, NiZn ferrite having a low saturation magnetic flux density Bs has a problem that magnetic saturation is likely to occur. Therefore, replacement of NiZn-based ferrite with MnZn-based ferrite having higher Bs has been studied.
ＮｉＺｎ系フェライトの比抵抗は１０４Ωｍ以上であり絶縁性が高いため、これを表面実装パワーインダクタ用磁芯として使用する場合には、ドラム形状のコアに直接巻線を施したり、ドラムの鍔部（フランジ部）に直接電極端子を付けたりすることができる。しかし、ＭｎＺｎ系フェライトの比抵抗は１０Ωｍ以下と低いため、直接巻線を施したり、直に電極を形成したりすることは難しく、何らかの絶縁処理が必要となっていた。そのため、ＮｉＺｎ系フェライトコアをそのままＭｎＺｎ系フェライトコアに置き換えることは従来困難とされていた。そこで、ＭｎＺｎ系フェライトの高い飽和磁束密度Ｂｓと初透磁率μｉを維持しつつ、ＮｉＺｎ系フェライト並みの比抵抗（１０４Ωｍ以上）を有する高抵抗高飽和磁束密度のＭｎＺｎ系フェライトの開発が求められていた。 Since the specific resistance of NiZn ferrite is 10 4 Ωm or more and has high insulation, when this is used as a magnetic core for a surface mount power inductor, the drum-shaped core is directly wound, An electrode terminal can be directly attached to the portion (flange portion). However, since the specific resistance of MnZn-based ferrite is as low as 10 Ωm or less, it is difficult to directly wind or form an electrode directly, and some kind of insulation treatment is necessary. Therefore, it has been conventionally difficult to replace the NiZn ferrite core with the MnZn ferrite core as it is. Therefore, development of a MnZn ferrite having a high resistance and a high saturation magnetic flux density having a specific resistance (10 4 Ωm or more) equivalent to that of a NiZn ferrite while maintaining the high saturation magnetic flux density Bs and initial permeability μi of the MnZn ferrite is required. It was done.
ここで、ＭｎＺｎ系フェライトの比抵抗を高める従来技術としては、ＭｎＺｎＣｏフェライトのＦｅ２Ｏ３配合比を５０ｍｏｌ％未満の鉄欠乏組成とする方法が開示されている（特許文献１，２参照）。 Here, as a conventional technique for increasing the specific resistance of MnZn-based ferrite, a method is disclosed in which the Fe 2 O 3 blending ratio of MnZnCo ferrite is set to an iron-deficient composition of less than 50 mol% (see Patent Documents 1 and 2).
特許文献１，２の技術によれば、１０２Ωｍ程度まで比抵抗を高め、２ＭＨｚ程度の高周波のコアロスの低減効果や１００ｋＨｚにおける初透磁率μｉの増大効果を得ることができる。しかし、フェライトコアに直接巻線を施すためには、さらに２桁以上の比抵抗の増大が必要とされる。また、コアロス低減やμｉ増大に特化した上記従来技術では、昨今の表面実装インダクタ用磁芯に求められている電磁気特性、すなわち、Ｂｓ≧４５０ｍＴで、比抵抗≧１０４Ωｍであり、かつ、１０ｋＨｚ〜１ＭＨｚの高周波帯域において高く平坦なμｉの周波数特性を有するという電磁気特性を全て満たすフェライトコアを得ることはできなかった。 According to the techniques of Patent Documents 1 and 2, the specific resistance can be increased to about 10 2 Ωm, and the effect of reducing the high-frequency core loss of about 2 MHz and the effect of increasing the initial permeability μi at 100 kHz can be obtained. However, in order to directly wind the ferrite core, it is necessary to further increase the specific resistance by two digits or more. In the above-mentioned conventional technology specialized in core loss reduction and μi increase, the electromagnetic characteristics required for the recent surface mount inductor magnetic core, that is, Bs ≧ 450 mT, specific resistance ≧ 10 4 Ωm, and It has not been possible to obtain a ferrite core satisfying all the electromagnetic characteristics of having a high and flat frequency characteristic of μi in a high frequency band of 10 kHz to 1 MHz.
特許文献３には、初透磁率が広い周波数帯域で維持されたＭｎＺｎ系フェライトとして、基本成分が、Ｆｅ２Ｏ３：４４．０〜５０．０ｍｏｌ％（ただし、５０．０ｍｏｌ％は除く）、ＺｎＯ：４．０〜２６．５ｍｏｌ％、残部ＭｎＯからなり、１ｋＨｚにおける複素比誘電率実数部ε´が２００００以下でかつ１ＭＨｚにおける複素比誘電率実数部ε´が５０以下であることを特徴とするＭｎＺｎ系フェライトが開示されている。 In Patent Document 3, as the MnZn-based ferrite whose initial permeability is maintained in a wide frequency band, the basic component is Fe 2 O 3 : 44.0 to 50.0 mol% (excluding 50.0 mol%), ZnO: 4.0 to 26.5 mol%, remaining MnO, characterized in that the complex relative permittivity real part ε ′ at 1 kHz is 20000 or less and the complex relative permittivity real part ε ′ at 1 MHz is 50 or less. An MnZn based ferrite is disclosed.
しかし、特許文献３の技術によっても、１０２Ωｍ程度まで比抵抗を高められるに過ぎない。 However, even with the technique of Patent Document 3, the specific resistance can only be increased to about 10 2 Ωm.
そこで本発明は、上記課題に鑑み、Ｂｓ≧４５０ｍＴで、比抵抗≧１０４Ωｍであり、かつ、１０ｋＨｚ〜１ＭＨｚの高周波帯域において高く平坦なμｉの周波数特性を有するという電磁気特性を全て満たす、表面実装インダクタ磁芯に適した高抵抗高飽和磁束密度のＭｎＺｎＡｌＣｏ系フェライトを提供することを目的とする。 In view of the above problems, the present invention satisfies all the electromagnetic characteristics of Bs ≧ 450 mT, specific resistance ≧ 10 4 Ωm, and high and flat μi frequency characteristics in a high frequency band of 10 kHz to 1 MHz. An object of the present invention is to provide a MnZnAlCo ferrite having a high resistance and a high saturation magnetic flux density suitable for a mounting inductor magnetic core.
発明者らは、基本成分の中でも配合量の多いＦｅ２Ｏ３，ＭｎＯおよびＺｎＯの配合比を決定するために、比抵抗の高いＦｅ２Ｏ３＜５０ｍｏｌ％の組成域で、ＭｎＯとＺｎＯの配合比を種々に変化させてフェライトコアを作製し、それぞれの成分が飽和磁束密度Ｂｓ、比抵抗、初透磁率μｉに及ぼす影響を調べた。その結果、高い比抵抗の得られるＦｅ２Ｏ３＜５０ｍｏｌ％の組成域では、１０ｋＨｚ付近の低周波帯域では周波数に依存しない一定のμｉ値が得られるが、１００ｋＨｚ付近から徐々にμｉが低下し始め、１ＭＨｚ程度の高周波域まで平坦なμｉの周波数特性を得ることができないことがわかった。 In order to determine the compounding ratio of Fe 2 O 3 , MnO and ZnO, which is a large amount among the basic components, the inventors of the present invention have a composition range of Fe 2 O 3 <50 mol% with high specific resistance. Ferrite cores were produced with various blending ratios, and the influence of each component on the saturation magnetic flux density Bs, specific resistance, and initial permeability μi was examined. As a result, in a composition region of Fe 2 O 3 <50 mol% where high specific resistance is obtained, a constant μi value independent of frequency is obtained in the low frequency band near 10 kHz, but μi gradually decreases from around 100 kHz. Initially, it was found that a flat frequency characteristic of μi could not be obtained up to a high frequency range of about 1 MHz.
そこで、発明者らは、μｉが高周波域で低下する原因を詳細に調べた結果、Ｆｅ２Ｏ３＜５０ｍｏｌ％の組成域では、周波数と温度に依存する損失成分ｔａｎδのピークが１００ｋＨｚを超える高周波帯域に存在し、その影響で１００ｋＨｚを超える高周波帯域のμｉ値が低下することが明らかになった。この高周波損失が発生する原因について、発明者らは以下のように推測している。Ｆｅ２Ｏ３＜５０ｍｏｌ％の組成域では、Ｆｅ２Ｏ３が５０ｍｏｌ％の化学量論組成よりもＦｅ含有量が少ないために、スピネル構造のＢサイトのＦｅ３＋が欠乏しており、本来はＭｎ２＋としてＢサイトに分布しているＭｎイオンの一部が電気的中性を維持するためにＭｎ３＋となり、１００ｋＨｚを超える高周波帯域で励磁されたときに、Ｍｎ２＋−Ｍｎ３＋間の電子の拡散現象が起こり、この結果として、周波数と温度に依存した高周波損失が発生するものと考えられる。 Therefore, the inventors have investigated in detail the cause of the decrease in μi in the high frequency range, and as a result, in the composition range of Fe 2 O 3 <50 mol%, the peak of the loss component tan δ depending on the frequency and temperature exceeds 100 kHz. It has been clarified that the μi value in the high frequency band exceeding 100 kHz is lowered due to the influence. The inventors presume the cause of this high-frequency loss as follows. In the composition range of Fe 2 O 3 <50 mol%, Fe 2 O 3 has a lower Fe content than the stoichiometric composition of 50 mol%, and therefore Fe 3+ at the B site of the spinel structure is deficient. A part of Mn ions distributed at the B site as Mn 2+ becomes Mn 3+ to maintain electric neutrality, and when excited in a high frequency band exceeding 100 kHz, electrons between Mn 2+ and Mn 3+ It is considered that a diffusion phenomenon occurs, and as a result, high frequency loss depending on frequency and temperature occurs.
そこで、本発明者らは、Ｆｅ２Ｏ３＜５０ｍｏｌ％の組成域におけるＭｎ３＋の生成を抑制する方法を検討した。その結果、Ｍｎ３＋よりもＢサイト選択性が高い成分として、スピネル構造の名前の由来であるスピネルＭｇＡｌ２Ｏ４のＢサイトに位置するＡｌをＭｎＺｎ系フェライトに導入すれば、Ｍｎ２＋−Ｍｎ３＋間の電子の拡散現象を抑え、高周波磁気損失を低減できることを見出した。 Therefore, the present inventors examined a method for suppressing the production of Mn 3+ in the composition range of Fe 2 O 3 <50 mol%. As a result, if Al located at the B site of the spinel MgAl 2 O 4 derived from the name of the spinel structure is introduced into the MnZn-based ferrite as a component having higher B site selectivity than Mn 3+ , Mn 2+ −Mn 3+ It was found that the high-frequency magnetic loss can be reduced by suppressing the phenomenon of electron diffusion between the two.
さらに、Ｆｅ２Ｏ３＜５０ｍｏｌ％の組成域では比抵抗が高いとはいえ、１０２Ωｍ程度であり、これを１０４Ωｍ以上とするべく鋭意検討した。その結果、Ｆｅ２Ｏ３＜５０ｍｏｌ％の鉄欠乏組成に対して、上記の所定量Ａｌ添加に加えて、ＳｉＯ２およびＣａＯを副成分として所定量添加することで、１０４Ωｍ以上の比抵抗が得られることを見出した。さらに、このような副成分を添加する場合でも、ＡｌをＭｎＺｎ系フェライトに導入することで高周波磁気損失を低減する効果は維持できることを見出し、本発明を完成させるに至った。 Furthermore, although the specific resistance is high in the composition range of Fe 2 O 3 <50 mol%, it is about 10 2 Ωm, and intensive studies were conducted to make this 10 4 Ωm or more. As a result, a specific resistance of 10 4 Ωm or more can be added to the iron-deficient composition of Fe 2 O 3 <50 mol% by adding a predetermined amount of SiO 2 and CaO as subcomponents in addition to the above-mentioned predetermined amount of Al addition. It was found that can be obtained. Furthermore, even when such subcomponents are added, it has been found that the effect of reducing high-frequency magnetic loss can be maintained by introducing Al into MnZn-based ferrite, and the present invention has been completed.
すなわち、上記課題に鑑み、本発明の要旨構成は以下の通りである。
（１）酸化鉄（Ｆｅ２Ｏ３換算）：４６．０〜４９．８ｍｏｌ％、
酸化亜鉛（ＺｎＯ換算）：２．０〜１８．０ｍｏｌ％、
酸化アルミニウム（Ａｌ２Ｏ３換算）：０．１〜１．５ｍｏｌ％、
酸化コバルト（ＣｏＯ換算）：０．１〜３．０ｍｏｌ％、
酸化マンガン（ＭｎＯ換算）：残部
からなる基本成分中に、さらに副成分として、
酸化ケイ素（ＳｉＯ２換算）と酸化カルシウム（ＣａＯ換算）を、合計で１００〜２５００質量ｐｐｍ含有し、かつ、酸化ケイ素（ＳｉＯ２換算）と酸化カルシウム（ＣａＯ換算）の混合比率を、モル％にして、酸化ケイ素（ＳｉＯ２換算）：０超え４０以下に対し、酸化カルシウム（ＣａＯ換算）：６０以上１００未満とすることを特徴とするＭｎＺｎＡｌＣｏ系フェライト。
That is, in view of the above problems, the gist of the present invention is as follows.
(1) Iron oxide (Fe 2 O 3 conversion): 46.0 to 49.8 mol%,
Zinc oxide (ZnO equivalent): 2.0-18.0 mol%,
Aluminum oxide (Al 2 O 3 conversion): 0.1 to 1.5 mol%,
Cobalt oxide (CoO equivalent): 0.1 to 3.0 mol%,
Manganese oxide (in terms of MnO): In addition to the remaining basic components,
Silicon oxide (SiO 2 equivalent) and calcium oxide (CaO equivalent) are contained in a total of 100 to 2500 mass ppm, and the mixing ratio of silicon oxide (SiO 2 equivalent) and calcium oxide (CaO equivalent) is set to mol%. And MnZnAlCo-based ferrite, characterized in that silicon oxide (SiO 2 equivalent): 0 to 40 or less, calcium oxide (CaO equivalent): 60 to less than 100.
（２）前記基本成分として、酸化マンガンの一部に代えて、酸化スズ（ＳｎＯ２換算）、酸化チタン（ＴｉＯ２換算）および酸化ゲルマニウム（ＧｅＯ２換算）から選ばれる少なくとも１種を合計で０．０５〜２．２ｍｏｌ％含有する上記（１）に記載のＭｎＺｎＡｌＣｏ系フェライト。 (2) As a basic component, instead of a part of manganese oxide, at least one selected from tin oxide (SnO 2 equivalent), titanium oxide (TiO 2 equivalent) and germanium oxide (GeO 2 equivalent) is 0 in total. The MnZnAlCo-based ferrite according to (1) above, containing 0.05 to 2.2 mol%.
本発明によれば、Ｂｓ≧４５０ｍＴで、比抵抗≧１０４Ωｍであり、かつ、１０ｋＨｚ〜１ＭＨｚの高周波帯域において高く平坦なμｉの周波数特性を有するという電磁気特性を全て満たす、表面実装インダクタ磁芯に適した高抵抗高飽和磁束密度のＭｎＺｎＡｌＣｏ系フェライトを提供することができる。 According to the present invention, a surface-mount inductor core satisfying all the electromagnetic characteristics of Bs ≧ 450 mT, specific resistance ≧ 10 4 Ωm, and high and flat μi frequency characteristics in a high frequency band of 10 kHz to 1 MHz. MnZnAlCo-based ferrite having high resistance and high saturation magnetic flux density suitable for the above can be provided.
以下、本発明をより詳細に説明する。
まず、本発明のＭｎＺｎＡｌＣｏ系フェライトは、基本組成を酸化鉄（Ｆｅ２Ｏ３換算）：４６．０〜４９．８ｍｏｌ％、酸化亜鉛（ＺｎＯ換算）：２．０〜１８．０ｍｏｌ％、酸化アルミニウム（Ａｌ２Ｏ３換算）：０．１〜１．５ｍｏｌ％、酸化コバルト（ＣｏＯ換算）：０．１〜３．０ｍｏｌ％、酸化マンガン（ＭｎＯ換算）：残部とすることで、Ｂｓ，比抵抗，μｉの優れたＭｎＺｎＡｌＣｏ系フェライトを実現する。以下、本発明のＭｎＺｎＡｌＣｏ系フェライトの基本成分組成について説明する。なお、基本成分の含有量はｍｏｌ％で示すものとし、これらの含有量の合計は１００ｍｏｌ％である。
Hereinafter, the present invention will be described in more detail.
First, the basic composition of the MnZnAlCo ferrite of the present invention is based on iron oxide (Fe 2 O 3 conversion): 46.0 to 49.8 mol%, zinc oxide (ZnO conversion): 2.0 to 18.0 mol%, aluminum oxide (Al 2 O 3 conversion): 0.1-1.5 mol%, cobalt oxide (CoO conversion): 0.1-3.0 mol%, manganese oxide (MnO conversion): the balance, Bs, specific resistance , Μi of MnZnAlCo-based ferrite is realized. Hereinafter, the basic component composition of the MnZnAlCo ferrite of the present invention will be described. In addition, content of a basic component shall be shown by mol% and the sum total of these content is 100 mol%.
酸化鉄（Ｆｅ２Ｏ３換算）：４６．０〜４９．８ｍｏｌ％
Ｆｅ２Ｏ３は、飽和磁束密度Ｂｓおよび比抵抗に大きく影響する成分である。Ｆｅ２Ｏ３の配合量が４６．０ｍｏｌ％未満では高周波帯域のμｉ値が低下し、４９．８ｍｏｌ％を超えると比抵抗が急激に低下する。そのため、Ｆｅ２Ｏ３の配合量は、４６．０〜４９．８ｍｏｌ％の範囲内とする。より好ましくは４７．０〜４９．６ｍｏｌ％である。
Iron oxide (Fe 2 O 3 conversion): 46.0 to 49.8 mol%
Fe 2 O 3 is a component that greatly affects the saturation magnetic flux density Bs and the specific resistance. When the compounding amount of Fe 2 O 3 is less than 46.0 mol%, the μi value in the high frequency band decreases, and when it exceeds 49.8 mol%, the specific resistance decreases rapidly. Therefore, the amount of Fe 2 O 3 is in the range of 46.0 to 49.8 mol%. More preferably, it is 47.0-49.6 mol%.
酸化亜鉛（ＺｎＯ換算）：２．０〜１８．０ｍｏｌ％
ＺｎＯは、Ｂｓ，初透磁率μｉおよびキュリー温度Ｔｃに大きく影響する成分である。ＺｎＯの配合量が２．０ｍｏｌ％未満では、全帯域を通して初透磁率μｉの値自体が小さくなり、一方、１８．０ｍｏｌ％を超えるとＢｓ≧４５０ｍＴを得ることができない。また、ＴｃはＺｎＯの配合量が多いほど低下し、ＺｎＯが１８．０ｍｏｌ％を超えると１５０℃以下となり、１００℃におけるＢｓが低下してしまう。よって、ＺｎＯの配合量は、２．０〜１８．０ｍｏｌ％の範囲内とする。より好ましくは６．０〜１３．０ｍｏｌ％であり、最も好ましくは８．０〜１３．０ｍｏｌ％である。
Zinc oxide (ZnO conversion): 2.0-18.0 mol%
ZnO is a component that greatly affects Bs, initial permeability μi, and Curie temperature Tc. If the blending amount of ZnO is less than 2.0 mol%, the value of the initial permeability μi itself is small throughout the entire band. On the other hand, if it exceeds 18.0 mol%, Bs ≧ 450 mT cannot be obtained. Further, Tc decreases as the blending amount of ZnO increases, and when ZnO exceeds 18.0 mol%, it becomes 150 ° C. or lower, and Bs at 100 ° C. decreases. Therefore, the compounding quantity of ZnO shall be in the range of 2.0-18.0 mol%. More preferably, it is 6.0-13.0 mol%, Most preferably, it is 8.0-13.0 mol%.
酸化コバルト（ＣｏＯ換算）：０．１〜３．０ｍｏｌ％
少量のＣｏＯを含有することでＢｓを大きく増大させる効果がある。ＣｏＯの配合量が０．１ｍｏｌ％未満ではＢｓの改善効果が小さく、一方、３．０ｍｏｌ％を超えると全帯域を通してμｉ値自体が低下する傾向があるため好ましくない。よって、ＣｏＯの配合量は、０．１〜３．０ｍｏｌ％の範囲内とする。より好ましくは０．２〜２．５ｍｏｌ％である。
Cobalt oxide (CoO equivalent): 0.1-3.0 mol%
By containing a small amount of CoO, there is an effect of greatly increasing Bs. If the blending amount of CoO is less than 0.1 mol%, the effect of improving Bs is small. On the other hand, if it exceeds 3.0 mol%, the μi value itself tends to decrease throughout the entire band, which is not preferable. Therefore, the blending amount of CoO is set in the range of 0.1 to 3.0 mol%. More preferably, it is 0.2-2.5 mol%.
なお、Ｃｏ２＋の磁気モーメントは３μＢであり、Ｍｎ２＋の５μＢより小さいため、理論上はＣｏＯの添加によるＢｓの増大効果は期待できない。しかしながら、本発明者らの検討によれば、少量のＣｏＯ添加でＢｓ増大効果が確認された。この原因は、現時点ではまだ十分に明らかではないが、Ｃｏ２＋は他の２価金属イオンと比べて著しく結晶磁気異方性が大きいため、周囲の金属イオンと磁気的に強く相互作用することで、２価金属イオンの磁気モーメントから推算する理論値よりも高い磁化が得られるものと考えられる。 The magnetic moment of Co 2+ is 3.mu. B, smaller than 5 [mu] B of Mn 2+, theoretically the effect of increasing the Bs by the addition of CoO can not be expected. However, according to the study by the present inventors, the effect of increasing Bs was confirmed with the addition of a small amount of CoO. The cause of this is not yet clear at this time, but Co 2+ has a significantly higher magnetocrystalline anisotropy than other divalent metal ions, and thus interacts strongly with surrounding metal ions. It is considered that magnetization higher than the theoretical value estimated from the magnetic moment of the divalent metal ion can be obtained.
酸化アルミニウム（Ａｌ２Ｏ３換算）：０．１〜１．５ｍｏｌ％
さらに、本発明のＭｎＺｎＡｌＣｏ系フェライトは、基本成分としてＡｌ２Ｏ３を０．１〜１．５ｍｏｌ％含有することで、高周波磁気損失ｔａｎδを低減してμｉの高周波特性を平坦化する効果と、粒界の絶縁性を改善して比抵抗を増大させる相乗効果が得られる。Ａｌ２Ｏ３の含有量が０．１ｍｏｌ％未満ではｔａｎδを低減する効果が十分でなく、１．５ｍｏｌ％を超えると、焼結密度が低下してＢｓが低下し、さらに比抵抗も低下する。よって、Ａｌ２Ｏ３の配合量は、０．１〜１．５ｍｏｌ％の範囲内とする。より好ましくは０．２〜１．０ｍｏｌ％である。
Aluminum oxide (Al 2 O 3 conversion): 0.1 to 1.5 mol%
Further, the MnZnAlCo-based ferrite of the present invention contains 0.1 to 1.5 mol% of Al 2 O 3 as a basic component, thereby reducing the high-frequency magnetic loss tan δ and flattening the high-frequency characteristics of μi, A synergistic effect of improving the resistivity of the grain boundaries and increasing the specific resistance is obtained. If the content of Al 2 O 3 is less than 0.1 mol%, the effect of reducing tan δ is not sufficient, and if it exceeds 1.5 mol%, the sintered density decreases, Bs decreases, and the specific resistance also decreases. . Therefore, the amount of Al 2 O 3 is in the range of 0.1~1.5mol%. More preferably, it is 0.2-1.0 mol%.
本発明のＭｎＺｎＡｌＣｏ系フェライトは、上記の基本成分中に、さらに副成分として、酸化ケイ素（ＳｉＯ２換算）と酸化カルシウム（ＣａＯ換算）を、合計で１００〜２５００質量ｐｐｍ含有し、かつ、酸化ケイ素（ＳｉＯ２換算）と酸化カルシウム（ＣａＯ換算）の混合比率を、モル％にして、酸化ケイ素（ＳｉＯ２換算）：０超え４０以下に対し、酸化カルシウム（ＣａＯ換算）：６０以上１００未満とすることで、６００℃以上の昇温速度≧５００℃／ｈｒ、最高温度１３００℃以上の高速連続炉で焼成しても、均一かつ緻密な結晶組織を得ることができる。よって、ＳｉＯ２とＣａＯを上記適正範囲で複合添加することによって、表面実装インダクタ用磁芯に適した電磁気特性を有するＭｎＺｎＡｌＣｏ系フェライトを、従来のＭｎＺｎ系フェライトと同様、生産性よく製造することが可能となる。 The MnZnAlCo ferrite of the present invention contains silicon oxide (SiO 2 equivalent) and calcium oxide (CaO equivalent) in a total amount of 100 to 2500 mass ppm as subcomponents in the above basic component, and silicon oxide. The mixing ratio of (SiO 2 equivalent) and calcium oxide (CaO equivalent) is mol%, and silicon oxide (SiO 2 equivalent): 0 to 40 or less, while calcium oxide (CaO equivalent): 60 to less than 100. Thus, even when fired in a fast continuous furnace having a temperature rising rate of 600 ° C. or higher ≧ 500 ° C./hr and a maximum temperature of 1300 ° C. or higher, a uniform and dense crystal structure can be obtained. Therefore, MnZnAlCo ferrite having electromagnetic characteristics suitable for a surface mount inductor magnetic core can be produced with high productivity, as with conventional MnZn ferrite, by adding SiO 2 and CaO in the appropriate range. It becomes possible.
また、これらの副成分は粒界に偏析して、粒界絶縁層を形成するため、比抵抗を増大させる効果がある。よって、主成分においてＦｅ２Ｏ３配合量を４６．０〜４９．８ｍｏｌ％（５０ｍｏｌ％未満）とし、上記所定量のＡｌ２Ｏ３を添加するのと併せて、上記の副成分を複合添加することによって、１０４Ωｍ以上の高い比抵抗を得ることができる。なお、酸化ケイ素および酸化カルシウムは、単独で添加された場合でも、粒界に偏析して、粒界絶縁層を形成する性質であり、若干比抵抗を増大させる効果があるが、１０４Ωｍ以上の比抵抗を得ることはできず、２つの副成分をともに添加することにより、初めて１０４Ωｍ以上の比抵抗を得ることができる。 In addition, these subcomponents segregate at the grain boundaries to form a grain boundary insulating layer, which has the effect of increasing the specific resistance. Therefore, the additive amount of Fe 2 O 3 in the main component is 46.0 to 49.8 mol% (less than 50 mol%), and the above-mentioned auxiliary component is added in combination with the addition of the predetermined amount of Al 2 O 3. By doing so, a high specific resistance of 10 4 Ωm or more can be obtained. Silicon oxide and calcium oxide have the property of segregating at the grain boundary to form a grain boundary insulating layer even when added alone, and have the effect of slightly increasing the specific resistance, but are not less than 10 4 Ωm. The specific resistance of 10 4 Ωm or more can be obtained for the first time by adding two subcomponents together.
ＳｉＯ２とＣａＯの合計添加量を１００〜２５００質量ｐｐｍの範囲とする理由は、以下の通りである。まず、１００質量ｐｐｍ未満では、高速焼成で緻密かつ均一な結晶組織を得る効果が不十分なために、高周波帯域でのμｉ値が低下する。また、添加量が少ないと粒界絶縁層が薄くなるため、比抵抗≧１０４Ωｍが得られず、コアに直接巻線や電極形成をすることができない。一方、２５００質量ｐｐｍを超えると、異常粒が発生するようになり、全帯域を通してμｉ値自体が低下する。上記の観点からより好ましい合計添加量は１０００〜２０００質量ｐｐｍである。なお、副成分の含有量は質量ｐｐｍで示すものとし、これは、基本成分の合計量を１００質量％とした場合の添加量を意味する。 The reason why the total amount of SiO 2 and CaO is in the range of 100 to 2500 ppm by mass is as follows. First, if it is less than 100 mass ppm, since the effect of obtaining a dense and uniform crystal structure by high-speed firing is insufficient, the μi value in the high frequency band decreases. Further, if the added amount is small, the grain boundary insulating layer becomes thin, so that the specific resistance ≧ 10 4 Ωm cannot be obtained, and the winding or electrode cannot be directly formed on the core. On the other hand, if it exceeds 2500 ppm by mass, abnormal grains will be generated, and the μi value itself will decrease throughout the entire band. From the above viewpoint, the more preferable total addition amount is 1000 to 2000 mass ppm. In addition, content of a subcomponent shall be shown by mass ppm, and this means the addition amount when the total amount of a basic component shall be 100 mass%.
ＳｉＯ２とＣａＯの混合比率は、モル％にして、酸化ケイ素（ＳｉＯ２換算）：０超え４０以下に対し、酸化カルシウム（ＣａＯ換算）：６０以上１００未満として、ＳｉＯ２とＣａＯを複合添加する必要がある。ＳｉＯ２とＣａＯが共存することで、昇温過程および焼成中に粒界に液相を生成して結晶組織を均一化する効果が得られるが、ＳｉＯ２の比率が４０ｍｏｌ％を超えると、異常粒が発生しやすくなり、特に高周波帯域でのμｉ値が低下し、比抵抗も小さくなるからである。好ましい混合比は、ＳｉＯ２：ＣａＯ＝５〜３５：９５〜７０（ｍｏｌ％）である。 The mixing ratio of SiO 2 and CaO is mol%, and silicon oxide (SiO 2 conversion): 0 to 40 or less, calcium oxide (CaO conversion): 60 to less than 100, and SiO 2 and CaO are added in combination. There is a need. The coexistence of SiO 2 and CaO provides the effect of generating a liquid phase at the grain boundary during the temperature raising process and firing, and uniforming the crystal structure, but if the SiO 2 ratio exceeds 40 mol%, abnormalities This is because grains are likely to be generated, and the μi value particularly in a high frequency band is lowered and the specific resistance is also reduced. A preferable mixing ratio is SiO 2 : CaO = 5 to 35:95 to 70 (mol%).
このようにして、本発明のＭｎＺｎＡｌＣｏ系フェライトは、昨今の表面実装インダクタ用磁芯に求められている電磁気特性として、以下の４つの条件を満たすものである。
１．室温での印加磁場１．２ｋＡ／ｍにおけるＢｓ≧４５０ｍＴ
２．比抵抗≧１０４Ωｍ
３．１０ｋＨｚ〜１ＭＨｚにおけるμｉ≧７８０
４．μｉ（１ＭＨｚ）≧０．９６×μｉ（１０ｋＨｚ）
条件４は、１ＭＨｚにおける初透磁率が、１０ｋＨｚにおける初透磁率を基準とした減少幅が、４％以内であることを意味する。
As described above, the MnZnAlCo ferrite of the present invention satisfies the following four conditions as the electromagnetic characteristics required for the recent surface mount inductor magnetic core.
1. Bs ≧ 450 mT at an applied magnetic field of 1.2 kA / m at room temperature
2. Specific resistance ≧ 10 4 Ωm
3. μi ≧ 780 at 10 kHz to 1 MHz
4). μi (1 MHz) ≧ 0.96 × μi (10 kHz)
Condition 4 means that the initial permeability at 1 MHz is within 4% of a decrease width based on the initial permeability at 10 kHz.
さらに、本発明のＭｎＺｎＡｌＣｏ系フェライトは、基本成分として、酸化マンガンの一部に代えて、酸化スズ（ＳｎＯ２換算）、酸化チタン（ＴｉＯ２換算）および酸化ゲルマニウム（ＧｅＯ２換算）から選ばれる少なくとも１種を合計で０．０５〜２．２ｍｏｌ％含有することで、さらにＢｓ，μｉおよび比抵抗を改善することができる。ＳｎＯ２はμｉおよびＢｓを増大させる効果があり、ＴｉＯ２はμｉを増大させ、μｉの周波数特性を平坦化する効果があり、ＧｅＯ２は比抵抗を増大させる効果がある。上記の効果を発現させるためには、かつ、合計添加量が０．０５ｍｏｌ％以上とするのが好ましい。しかし、合計添加量が２．２ｍｏｌ％を超えると、比抵抗が１０４Ωｍ未満に低下したり、高周波帯域でのμｉ値が低下したりするため好ましくない。より好ましい合計添加量は０．１〜１．５ｍｏｌ％である。 Further, the MnZnAlCo ferrite of the present invention is at least selected from tin oxide (converted to SnO 2 ), titanium oxide (converted to TiO 2 ), and germanium oxide (converted to GeO 2 ) as a basic component instead of a part of manganese oxide. Bs, μi and specific resistance can be further improved by adding 0.05 to 2.2 mol% of one kind in total. SnO 2 has the effect of increasing μi and Bs, TiO 2 has the effect of increasing μi and flattening the frequency characteristics of μi, and GeO 2 has the effect of increasing the specific resistance. In order to exhibit the above effects, the total addition amount is preferably 0.05 mol% or more. However, if the total addition amount exceeds 2.2 mol%, the specific resistance decreases to less than 10 4 Ωm, and the μi value in the high frequency band decreases, which is not preferable. A more preferable total addition amount is 0.1 to 1.5 mol%.
次に、本発明のＭｎＺｎＡｌＣｏ系フェライトの製造方法について説明する。
本発明のＭｎＺｎＡｌＣｏ系フェライトは、焼成後の成分組成が上記適正範囲となるように出発原料を配合しさえすれば、特に限定されるものではなく、通常のフェライト製造方法を適用することができる。好ましい製造方法としては、例えば、出発原料となるＦｅ２Ｏ３，Ｍｎ３Ｏ４またはＭｎＣＯ３，ＺｎＯ，ＣｏＯまたはＣｏ３Ｏ４，Ａｌ２Ｏ３，（必要によりＳｎＯ２，ＴｉＯ２，ＧｅＯ２）を適正量秤量し、これらをアトライターやボールミルなどの混合機を用いて、湿式または乾式で混合した後、８００〜１０００℃で仮焼する。その後、その仮焼粉に上記適正範囲の副成分を添加し、アトライターやボールミルなどの混合機を用いて、湿式または乾式で混合し、粉砕して粒径が０．８〜１．６μｍ程度の原料粉とする。その後、その原料粉にＰＶＡ（ポリビニルアルコール）などの結合剤（バインダー）を添加し、スプレードライヤーや篩を用いて造粒した後、その造粒粉を所定形状の金型に充填してプレス成形する。その後、その成形体を焼成することによって、本発明のＭｎＺｎＡｌＣｏ系フェライトを製造することができる。なお、上記の焼成は、鉄過剰組成を有する一般的なＭｎＺｎ系フェライトと同様のヒートパターンおよび雰囲気で行うことができ、特別な条件は必要とされない。したがって、従来のＭｎＺｎ系フェライトと同様、高い生産性で製造することが可能である。
Next, a method for producing the MnZnAlCo ferrite of the present invention will be described.
The MnZnAlCo-based ferrite of the present invention is not particularly limited as long as the starting material is blended so that the component composition after firing is within the above-described appropriate range, and a normal ferrite production method can be applied. Preferable production methods include, for example, Fe 2 O 3 , Mn 3 O 4 or MnCO 3 , ZnO, CoO or Co 3 O 4 , Al 2 O 3 , (SnO 2 , TiO 2 , GeO 2 as necessary) as starting materials. ) Is weighed in an appropriate amount, and these are mixed by a wet or dry method using a mixer such as an attritor or a ball mill, and then calcined at 800 to 1000 ° C. Then, the auxiliary component in the appropriate range is added to the calcined powder, mixed using a mixer such as an attritor or a ball mill, wet or dry, and pulverized to have a particle size of about 0.8 to 1.6 μm. The raw material powder. After that, a binder (binder) such as PVA (polyvinyl alcohol) is added to the raw material powder, granulated using a spray dryer or sieve, and then the granulated powder is filled into a mold having a predetermined shape and press-molded. To do. Then, the MnZnAlCo-based ferrite of the present invention can be manufactured by firing the compact. In addition, said baking can be performed by the heat pattern and atmosphere similar to the general MnZn type ferrite which has an iron excess composition, and special conditions are not required. Therefore, as with conventional MnZn ferrite, it can be manufactured with high productivity.
なお、ＣｏＯまたはＣｏ３Ｏ４，Ａｌ２Ｏ３などの比較的少量の基本成分は、仮焼粉の粉砕時に、他の副成分と同時に添加しても良い。また、上記製造方法は、一般的なフェライトの製造方法であるが、本発明のＭｎＺｎＡｌＣｏ系フェライトの製造方法は、上記方法に限定されるものではなく、例えば、成形前の原料粉の製造方法として、混合焙焼法や共沈法などの特殊な方法を用いてもよい。また、成形方法についても、プレス成形に限定されるものではなく、例えば、射出成形法、フェライトペースト印刷法、グリーンシート法など、種々の方法を適用することができる。 A relatively small amount of basic components such as CoO, Co 3 O 4 , and Al 2 O 3 may be added simultaneously with other subcomponents when the calcined powder is pulverized. Moreover, although the said manufacturing method is a general manufacturing method of a ferrite, the manufacturing method of the MnZnAlCo type ferrite of this invention is not limited to the said method, For example, as a manufacturing method of the raw material powder before shaping | molding Alternatively, a special method such as a mixed roasting method or a coprecipitation method may be used. Further, the molding method is not limited to press molding, and various methods such as an injection molding method, a ferrite paste printing method, and a green sheet method can be applied.
（実施例１）
焼成後のＭｎＺｎＡｌＣｏ系フェライトの基本成分組成が表１に示した値となるように、基本成分の原料であるＦｅ２Ｏ３，ＺｎＯ，Ｍｎ３Ｏ４，ＣｏＯ，Ａｌ２Ｏ３を秤量し、これをボールミルで湿式混合した後、９００℃で仮焼した。次いで、上記仮焼粉に、副成分としてＳｉＯ２，ＣａＣＯ３を、基本成分中への不純物としての混合量とも併せてＳｉＯ２＝１５０質量ｐｐｍ，ＣａＯ＝１８００質量ｐｐｍとなるように添加し、ボールミルでさらに湿式粉砕して平均粒径１．１μｍ（空気透過法で測定）の原料粉を得た。これにバインダーとしてＰＶＡを加え、目開き５００μｍの篩を通して造粒した後、リング型試料に成形した。その後、上記成形体を、電気炉を用いて、酸素分圧を制御した雰囲気中で１３４０℃×３時間の焼成を行い、外径３１ｍｍ、内径１９ｍｍ、高さ７ｍｍのＭｎＺｎＡｌＣｏ系フェライトコアを得た。
Example 1
The basic component raw materials Fe 2 O 3 , ZnO, Mn 3 O 4 , CoO, Al 2 O 3 are weighed so that the basic component composition of the MnZnAlCo-based ferrite after firing becomes the value shown in Table 1. This was wet-mixed with a ball mill and then calcined at 900 ° C. Next, to the calcined powder, SiO 2 and CaCO 3 are added as subcomponents together with the mixing amount as an impurity in the basic component so that SiO 2 = 150 mass ppm and CaO = 1800 mass ppm, It was further wet pulverized by a ball mill to obtain a raw material powder having an average particle size of 1.1 μm (measured by an air permeation method). PVA was added to this as a binder, granulated through a sieve having an opening of 500 μm, and then molded into a ring type sample. Thereafter, the molded body was fired at 1340 ° C. for 3 hours in an atmosphere with controlled oxygen partial pressure using an electric furnace to obtain an MnZnAlCo ferrite core having an outer diameter of 31 mm, an inner diameter of 19 mm, and a height of 7 mm. .
上記のようにして得られたフェライトコアについて、高抵抗計（アドバンテスト社製Ｒ８３４０Ａ）を用いて、印加電圧１０Ｖで比抵抗を測定した。また、フェライトコアに０．６ｍｍφの被覆銅線を１０回巻き、ＬＣＲメータ（アジレント・テクノロジー社製４２８４Ａおよび４２８５Ａ）を用いて、室温での１ｋＨｚ〜３０ＭＨｚにおけるμｉの周波数特性を測定した。さらに、直流ＢＨアナライザー（理研電子社製）を用いて、室温での印加磁場強度１．２ｋＡ／ｍにおける飽和磁束密度Ｂｓを測定した。 With respect to the ferrite core obtained as described above, the specific resistance was measured at an applied voltage of 10 V using a high resistance meter (R8340A manufactured by Advantest Corporation). Further, a 0.6 mmφ coated copper wire was wound around the ferrite core 10 times, and the frequency characteristic of μi at 1 kHz to 30 MHz at room temperature was measured using an LCR meter (Agilent Technology 4284A and 4285A). Furthermore, the saturation magnetic flux density Bs at an applied magnetic field strength of 1.2 kA / m at room temperature was measured using a DC BH analyzer (manufactured by Riken Denshi Co., Ltd.).
上記測定の結果を表１中に併記して示した。なお、μｉについては、１０ｋＨｚと１ＭＨｚの値を代表値として示した。表１から、本発明に適合した発明例のフェライトコアは、いずれも、以下の条件を満たしていることがわかる。
１．Ｂｓ≧４５０ｍＴ
２．比抵抗≧１０４Ωｍ
３．１０ｋＨｚおよび１ＭＨｚにおけるμｉ≧７８０
４．μｉ（１ＭＨｚ）≧０．９６×μｉ（１０ｋＨｚ）
The results of the above measurements are shown together in Table 1. For μi, values of 10 kHz and 1 MHz are shown as representative values. From Table 1, it can be seen that all of the ferrite cores of the inventive examples suitable for the present invention satisfy the following conditions.
1. Bs ≧ 450mT
2. Specific resistance ≧ 10 4 Ωm
3. μi ≧ 780 at 10 kHz and 1 MHz
4). μi (1 MHz) ≧ 0.96 × μi (10 kHz)
（実施例２）
実施例１とは異なる比率と量の副成分として、実施例１と同様の実験を行った。具体的には、焼成後のＭｎＺｎＡｌＣｏ系フェライトの基本成分組成が表２に示した値となるように、基本成分の原料であるＦｅ２Ｏ３，ＺｎＯ，Ｍｎ３Ｏ４，ＣｏＯ，Ａｌ２Ｏ３を秤量し、ボールミルで湿式混合した後、９５０℃で仮焼した。次いで、上記仮焼粉に、副成分としてＳｉＯ２，ＣａＣＯ３を、基本成分中への不純物としての混合量とも併せてＳｉＯ２＝２００質量ｐｐｍ，ＣａＯ＝１５００質量ｐｐｍとなるように添加し、ボールミルで湿式粉砕して平均粒径１．２μｍ（空気透過法）の原料粉を得た。実施例１と同様にリング型試料に成形した後、電気炉を用いて、酸素分圧を制御した雰囲気中で１３３０℃×５時間の焼成を行い、外径３１ｍｍ、内径１９ｍｍ、高さ７ｍｍのＭｎＺｎＡｌＣｏ系フェライトコアを得た。
(Example 2)
Experiments similar to those in Example 1 were performed as subcomponents having ratios and amounts different from those in Example 1. Specifically, the basic component raw materials Fe 2 O 3 , ZnO, Mn 3 O 4 , CoO, Al 2 O so that the basic component composition of the MnZnAlCo-based ferrite after firing has the values shown in Table 2. 3 was weighed and wet mixed with a ball mill, and then calcined at 950 ° C. Next, SiO 2 and CaCO 3 are added to the calcined powder as subcomponents together with the mixing amount as an impurity in the basic component so that SiO 2 = 200 mass ppm and CaO = 1500 mass ppm, A raw powder having an average particle size of 1.2 μm (air permeation method) was obtained by wet pulverization with a ball mill. After forming into a ring-shaped sample in the same manner as in Example 1, firing was performed at 1330 ° C. for 5 hours in an atmosphere with controlled oxygen partial pressure using an electric furnace, and the outer diameter was 31 mm, the inner diameter was 19 mm, and the height was 7 mm. An MnZnAlCo ferrite core was obtained.
比抵抗、μｉ、Ｂｓの測定は実施例１と同様にして行った。 The specific resistance, μi, and Bs were measured in the same manner as in Example 1.
上記測定の結果を表２中に併記して示した。表２から、本発明に適合した発明例のフェライトコアは、いずれも、以下の条件を満たしていることがわかる。
１．Ｂｓ≧４５０ｍＴ
２．比抵抗≧１０４Ωｍ
３．１０ｋＨｚおよび１ＭＨｚにおけるμｉ≧７８０
４．μｉ（１ＭＨｚ）≧０．９６×μｉ（１０ｋＨｚ）
The measurement results are shown together in Table 2. From Table 2, it can be seen that all of the ferrite cores of the inventive examples suitable for the present invention satisfy the following conditions.
1. Bs ≧ 450mT
2. Specific resistance ≧ 10 4 Ωm
3. μi ≧ 780 at 10 kHz and 1 MHz
4). μi (1 MHz) ≧ 0.96 × μi (10 kHz)
（実施例３）
主成分を固定し、副成分の添加量を種々の値として、実施例１と同様の実験を行った。具体的には、焼成後のＭｎＺｎＡｌＣｏ系フェライトの基本成分組成がＦｅ２Ｏ３：ＺｎＯ：ＭｎＯ：ＣｏＯ：Ａｌ２Ｏ３＝４７．５：１０：４１：１：０．５（ｍｏｌ％）の組成となるように、基本成分の原料であるＦｅ２Ｏ３，ＺｎＯ，Ｍｎ３Ｏ４，ＣｏＯ，Ａｌ２Ｏ３を秤量し、ボールミルで湿式混合した後、９５０℃で仮焼した。次いで、上記仮焼粉に、副成分としてＳｉＯ２，ＣａＣＯ３を、基本成分中への不純物としての混合量とも併せて表３に示す含有量となるように添加し、ボールミルで湿式粉砕して平均粒径１．２μｍ（空気透過法）の原料粉を得た。実施例１と同様にリング型試料に成形した後、電気炉を用いて、酸素分圧を制御した雰囲気中で１３２０℃×２時間の焼成を行い、外径３１ｍｍ、内径１９ｍｍ、高さ７ｍｍのＭｎＺｎＡｌＣｏ系フェライトコアを得た。
(Example 3)
Experiments similar to those of Example 1 were performed with the main component fixed and the amount of subcomponent added to various values. Specifically, the basic component composition of the MnZnAlCo-based ferrite after firing is Fe 2 O 3 : ZnO: MnO: CoO: Al 2 O 3 = 47.5: 10: 41: 1: 0.5 (mol%). Fe 2 O 3 , ZnO, Mn 3 O 4 , CoO, Al 2 O 3 which are raw materials of the basic components were weighed so as to have a composition, wet-mixed with a ball mill, and then calcined at 950 ° C. Next, SiO 2 and CaCO 3 as subcomponents are added to the calcined powder so as to have the content shown in Table 3 together with the mixing amount as an impurity in the basic component, and wet pulverized with a ball mill. A raw material powder having an average particle size of 1.2 μm (air permeation method) was obtained. After forming into a ring-shaped sample in the same manner as in Example 1, firing was performed at 1320 ° C. for 2 hours in an atmosphere with controlled oxygen partial pressure using an electric furnace, and the outer diameter was 31 mm, the inner diameter was 19 mm, and the height was 7 mm. An MnZnAlCo ferrite core was obtained.
比抵抗、μｉ、Ｂｓの測定は実施例１と同様にして行った。 The specific resistance, μi, and Bs were measured in the same manner as in Example 1.
上記測定の結果を表３中に併記して示した。表３から、本発明に適合した発明例のフェライトコアは、いずれも、以下の条件を満たしていることがわかる。
１．Ｂｓ≧４５０ｍＴ
２．比抵抗≧１０４Ωｍ
３．１０ｋＨｚおよび１ＭＨｚにおけるμｉ≧７８０
４．μｉ（１ＭＨｚ）≧０．９６×μｉ（１０ｋＨｚ）
The results of the above measurements are shown together in Table 3. From Table 3, it can be seen that all of the ferrite cores of the inventive examples suitable for the present invention satisfy the following conditions.
1. Bs ≧ 450mT
2. Specific resistance ≧ 10 4 Ωm
3. μi ≧ 780 at 10 kHz and 1 MHz
4). μi (1 MHz) ≧ 0.96 × μi (10 kHz)
（実施例４）
主成分の比率を実施例３とは異ならせ、副成分の添加量を種々の値として、実施例３と同様の実験を行った。具体的には、焼成後のＭｎＺｎＡｌＣｏ系フェライトの基本成分組成がＦｅ２Ｏ３：ＺｎＯ：ＭｎＯ：ＣｏＯ：Ａｌ２Ｏ３＝４８．８：９．５：３９．３５：１．６：０．７５（ｍｏｌ％）の組成となるように、基本成分の原料であるＦｅ２Ｏ３，ＺｎＯ，Ｍｎ３Ｏ４，ＣｏＯ，Ａｌ２Ｏ３を秤量し、ボールミルで湿式混合した後、９００℃で仮焼した。次いで、上記仮焼粉に、副成分としてＳｉＯ２，ＣａＣＯ３を、基本成分中への不純物としての混合量とも併せて表４に示す含有量となるように添加し、ボールミルで湿式粉砕して平均粒径１．１μｍ（空気透過法）の原料粉を得た。実施例１と同様にリング型試料に成形した後、電気炉を用いて、酸素分圧を制御した雰囲気中で１３５０℃×１時間の焼成を行い、外径３１ｍｍ、内径１９ｍｍ、高さ７ｍｍのＭｎＺｎＡｌＣｏ系フェライトコアを得た。
Example 4
Experiments similar to those in Example 3 were performed with the ratio of the main component different from that in Example 3 and various addition amounts of subcomponents. Specifically, the basic component composition of the MnZnAlCo-based ferrite after firing is Fe 2 O 3 : ZnO: MnO: CoO: Al 2 O 3 = 48.8: 9.5: 39.35: 1.6: 0. Fe 2 O 3 , ZnO, Mn 3 O 4 , CoO, Al 2 O 3 which are raw materials of basic components are weighed so as to have a composition of 75 (mol%), wet-mixed with a ball mill, and then at 900 ° C. It was calcined. Next, SiO 2 and CaCO 3 as subcomponents are added to the calcined powder so as to have the content shown in Table 4 together with the mixing amount as an impurity in the basic component, and wet pulverized with a ball mill. A raw material powder having an average particle size of 1.1 μm (air permeation method) was obtained. After forming into a ring-shaped sample in the same manner as in Example 1, firing was performed at 1350 ° C. for 1 hour in an atmosphere with controlled oxygen partial pressure using an electric furnace, and the outer diameter was 31 mm, the inner diameter was 19 mm, and the height was 7 mm. An MnZnAlCo ferrite core was obtained.
比抵抗、μｉ、Ｂｓの測定は実施例１と同様にして行った。 The specific resistance, μi, and Bs were measured in the same manner as in Example 1.
上記測定の結果を表４中に併記して示した。表４から、本発明に適合した発明例のフェライトコアは、いずれも、以下の条件を満たしていることがわかる。
１．Ｂｓ≧４５０ｍＴ
２．比抵抗≧１０４Ωｍ
３．１０ｋＨｚおよび１ＭＨｚにおけるμｉ≧７８０
４．μｉ（１ＭＨｚ）≧０．９６×μｉ（１０ｋＨｚ）
The results of the above measurements are shown together in Table 4. From Table 4, it can be seen that all of the ferrite cores of the inventive examples suitable for the present invention satisfy the following conditions.
1. Bs ≧ 450mT
2. Specific resistance ≧ 10 4 Ωm
3. μi ≧ 780 at 10 kHz and 1 MHz
4). μi (1 MHz) ≧ 0.96 × μi (10 kHz)
（実施例５）
主成分として、ＭｎＯの一部に代えてＳｎＯ２，ＴｉＯ２，ＧｅＯ２から選ばれる少なくとも１種を含めて、同様の実験を行った。具体的には、焼成後のＭｎＺｎＡｌＣｏ系フェライトの基本成分組成がＦｅ２Ｏ３：ＺｎＯ：ＭｎＯ：ＣｏＯ：Ａｌ２Ｏ３＝４７．５：１０：（残部）：１：０．５（ｍｏｌ％）の組成となるように、基本成分の原料であるＦｅ２Ｏ３，ＺｎＯ，Ｍｎ３Ｏ４，ＣｏＯ，Ａｌ２Ｏ３を秤量し、ボールミルで湿式混合した後、９５０℃で仮焼した。次いで、上記仮焼粉に、副成分として表３のＮｏ．３−３と同じＳｉＯ２＝１８０質量ｐｐｍ，ＣａＯ＝２０００質量ｐｐｍとなるように、ＳｉＯ２，ＣａＣＯ３を加えて、表５に示す量のＳｎＯ２，ＴｉＯ２，ＧｅＯ２を添加し、ボールミルで湿式粉砕して平均粒径１．２μｍ（空気透過法）の原料粉を得た。実施例３と同じ条件で成形、焼成を行い、外径３１ｍｍ、内径１９ｍｍ、高さ７ｍｍのＭｎＺｎＡｌＣｏ系フェライトコアを得た。なお、上記のＭｎＯ：残部とは、ＳｎＯ２，ＴｉＯ２，ＧｅＯ２をも含めたものである。
(Example 5)
The same experiment was performed including at least one selected from SnO 2 , TiO 2 , and GeO 2 as a main component instead of a part of MnO. Specifically, the basic component composition of the MnZnAlCo ferrite after firing is Fe 2 O 3 : ZnO: MnO: CoO: Al 2 O 3 = 47.5: 10: (remainder): 1: 0.5 (mol%) ) Fe 2 O 3 , ZnO, Mn 3 O 4 , CoO, Al 2 O 3 which are raw materials of basic components were weighed and wet-mixed with a ball mill, and then calcined at 950 ° C. Subsequently, No. of Table 3 was added to the said calcined powder as a subcomponent. In addition, SiO 2 and CaCO 3 were added so that SiO 2 = 180 ppm by mass and CaO = 2000 ppm by mass as in 3-3, and SnO 2 , TiO 2 and GeO 2 in amounts shown in Table 5 were added. To obtain a raw material powder having an average particle size of 1.2 μm (air permeation method). Molding and firing were performed under the same conditions as in Example 3 to obtain a MnZnAlCo ferrite core having an outer diameter of 31 mm, an inner diameter of 19 mm, and a height of 7 mm. Note that the above MnO: balance includes SnO 2 , TiO 2 , and GeO 2 .
比抵抗、μｉ、Ｂｓの測定は実施例１と同様にして行った。 The specific resistance, μi, and Bs were measured in the same manner as in Example 1.
上記測定の結果を表５中に併記して示した。表５から、本発明に適合した発明例のフェライトコアは、いずれも、以下の条件を満たしていることがわかる。
１．Ｂｓ≧４５０ｍＴ
２．比抵抗≧１０４Ωｍ
３．１０ｋＨｚおよび１ＭＨｚにおけるμｉ≧７８０
４．μｉ（１ＭＨｚ）≧０．９６×μｉ（１０ｋＨｚ）
The results of the above measurements are shown together in Table 5. From Table 5, it can be seen that all of the ferrite cores of the inventive examples suitable for the present invention satisfy the following conditions.
1. Bs ≧ 450mT
2. Specific resistance ≧ 10 4 Ωm
3. μi ≧ 780 at 10 kHz and 1 MHz
4). μi (1 MHz) ≧ 0.96 × μi (10 kHz)
（実施例６）
ＳｎＯ２，ＴｉＯ２，ＧｅＯ２から選ばれる追加の基本成分の比率を実施例５と同様にして、それ以外の主成分の比率と副成分の添加量を実施例５とは異ならせ、実施例５と同様の実験を行った。具体的には、焼成後のＭｎＺｎＡｌＣｏ系フェライトの基本成分組成がＦｅ２Ｏ３：ＺｎＯ：ＭｎＯ：ＣｏＯ：Ａｌ２Ｏ３＝４８．８：９．５：（残部）：１．６：０．７５（ｍｏｌ％）の組成となるように、基本成分の原料であるＦｅ２Ｏ３，ＺｎＯ，Ｍｎ３Ｏ４，ＣｏＯ，Ａｌ２Ｏ３を秤量し、ボールミルで湿式混合した後、９００℃で仮焼した。次いで、上記仮焼粉に、副成分として表４のＮｏ．４−１と同じＳｉＯ２＝２００質量ｐｐｍ，ＣａＯ＝６００質量ｐｐｍとなるように、ＳｉＯ２，ＣａＣＯ３を加えて、表６に示す量のＳｎＯ２，ＴｉＯ２，ＧｅＯ２を添加し、ボールミルで湿式粉砕して平均粒径１．１μｍ（空気透過法）の原料粉を得た。実施例５と同じ条件で成形、焼成を行い、外径３１ｍｍ、内径１９ｍｍ、高さ７ｍｍのＭｎＺｎＡｌＣｏ系フェライトコアを得た。なお、上記のＭｎＯ：残部とは、ＳｎＯ２，ＴｉＯ２，ＧｅＯ２をも含めたものである。
(Example 6)
The ratio of the additional basic component selected from SnO 2 , TiO 2 , and GeO 2 is set in the same manner as in the fifth embodiment, and the ratio of the other main components and the added amount of the subcomponents are different from those in the fifth embodiment. The same experiment as 5 was performed. Specifically, the basic component composition of the sintered MnZnAlCo ferrite is Fe 2 O 3 : ZnO: MnO: CoO: Al 2 O 3 = 48.8: 9.5: (remainder): 1.6: 0. Fe 2 O 3 , ZnO, Mn 3 O 4 , CoO, Al 2 O 3 which are raw materials of basic components are weighed so as to have a composition of 75 (mol%), wet-mixed with a ball mill, and then at 900 ° C. It was calcined. Subsequently, No. of Table 4 was added to the said calcined powder as a subcomponent. In addition, SiO 2 and CaCO 3 were added so that the same SiO 2 = 200 mass ppm and CaO = 600 mass ppm as in 4-1, and the amounts of SnO 2 , TiO 2 , and GeO 2 shown in Table 6 were added. To obtain a raw material powder having an average particle size of 1.1 μm (air permeation method). Molding and firing were performed under the same conditions as in Example 5 to obtain a MnZnAlCo ferrite core having an outer diameter of 31 mm, an inner diameter of 19 mm, and a height of 7 mm. Note that the above MnO: balance includes SnO 2 , TiO 2 , and GeO 2 .
比抵抗、μｉ、Ｂｓの測定は実施例１と同様にして行った。 The specific resistance, μi, and Bs were measured in the same manner as in Example 1.
上記測定の結果を表６中に併記して示した。表６から、本発明に適合した発明例のフェライトコアは、いずれも、以下の条件を満たしていることがわかる。
１．Ｂｓ≧４５０ｍＴ
２．比抵抗≧１０４Ωｍ
３．１０ｋＨｚおよび１ＭＨｚにおけるμｉ≧７８０
４．μｉ（１ＭＨｚ）≧０．９６×μｉ（１０ｋＨｚ）
The results of the above measurements are shown together in Table 6. From Table 6, it can be seen that all of the ferrite cores of the inventive examples suitable for the present invention satisfy the following conditions.
1. Bs ≧ 450mT
2. Specific resistance ≧ 10 4 Ωm
3. μi ≧ 780 at 10 kHz and 1 MHz
4). μi (1 MHz) ≧ 0.96 × μi (10 kHz)
以上の実施例で示した通り、本発明により、μｉが高く、Ｂｓ≧４５０ｍＴで、比抵抗≧１０４Ωｍであり、周波数１０ｋＨｚ〜１ＭＨｚで平坦なμｉの周波数特性を有する、表面実装インダクタ用磁芯に適したＭｎＺｎＡｌＣｏ系フェライトを生産性良く製造できる。 As shown in the above embodiments, according to the present invention, the magnetic field for a surface mount inductor having a high μi, Bs ≧ 450 mT, specific resistance ≧ 10 4 Ωm, and a flat μi frequency characteristic at a frequency of 10 kHz to 1 MHz. MnZnAlCo ferrite suitable for the core can be produced with high productivity.
本発明によれば、Ｂｓ≧４５０ｍＴで、比抵抗≧１０４Ωｍであり、かつ、１０ｋＨｚ〜１ＭＨｚの高周波帯域において高く平坦なμｉの周波数特性を有するという電磁気特性を全て満たす、表面実装インダクタ磁芯に適した高抵抗高飽和磁束密度のＭｎＺｎＡｌＣｏ系フェライトを提供することができる。
According to the present invention, a surface-mount inductor core satisfying all the electromagnetic characteristics of Bs ≧ 450 mT, specific resistance ≧ 10 4 Ωm, and high and flat μi frequency characteristics in a high frequency band of 10 kHz to 1 MHz. MnZnAlCo-based ferrite having high resistance and high saturation magnetic flux density suitable for the above can be provided.
Claims (2)
酸化亜鉛（ＺｎＯ換算）：２．０〜１８．０ｍｏｌ％、
酸化アルミニウム（Ａｌ２Ｏ３換算）：０．１〜１．５ｍｏｌ％、
酸化コバルト（ＣｏＯ換算）：０．１〜３．０ｍｏｌ％および
酸化マンガン（ＭｎＯ換算）：残部
からなる基本成分中に、さらに副成分として、
酸化ケイ素（ＳｉＯ２換算）と酸化カルシウム（ＣａＯ換算）を、合計で１００〜２５００質量ｐｐｍ含有し、かつ、酸化ケイ素（ＳｉＯ２換算）と酸化カルシウム（ＣａＯ換算）の混合比率を、モル％にして、酸化ケイ素（ＳｉＯ２換算）：０超え４０以下に対し、酸化カルシウム（ＣａＯ換算）：６０以上１００未満とすることを特徴とするＭｎＺｎＡｌＣｏ系フェライト。 Iron oxide (Fe 2 O 3 conversion): 46.0-49.8 mol%,
Zinc oxide (ZnO equivalent): 2.0-18.0 mol%,
Aluminum oxide (Al 2 O 3 conversion): 0.1 to 1.5 mol%,
Cobalt oxide (CoO equivalent): 0.1 to 3.0 mol% and manganese oxide (MnO equivalent): In the basic component consisting of the balance,
Silicon oxide (SiO 2 equivalent) and calcium oxide (CaO equivalent) are contained in a total of 100 to 2500 mass ppm, and the mixing ratio of silicon oxide (SiO 2 equivalent) and calcium oxide (CaO equivalent) is set to mol%. And MnZnAlCo-based ferrite, characterized in that silicon oxide (SiO 2 equivalent): 0 to 40 or less, calcium oxide (CaO equivalent): 60 to less than 100.
As the basic component, instead of a part of manganese oxide, at least one selected from tin oxide (converted to SnO 2 ), titanium oxide (converted to TiO 2 ) and germanium oxide (converted to GeO 2 ) is 0.05 to The MnZnAlCo-based ferrite according to claim 1, containing 2.2 mol%.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JPH06310320A (en) * | 1993-04-22 | 1994-11-04 | Matsushita Electric Ind Co Ltd | Oxide magnetic substance material |
| JP2003257724A (en) * | 2002-03-04 | 2003-09-12 | Hitachi Metals Ltd | Mn-Zn-BASED FERRITE |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| KR20180122229A (en) * | 2017-05-02 | 2018-11-12 | 엘지전자 주식회사 | Ferrite composition for shielding magnetic field and method for manufacturing the same |
| KR102344888B1 (en) | 2017-05-02 | 2021-12-30 | 엘지전자 주식회사 | Ferrite composition for shielding magnetic field and method for manufacturing the same |
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