JP4074437B2 - Magnetic oxide sintered body and high-frequency circuit component using the same - Google Patents
Magnetic oxide sintered body and high-frequency circuit component using the same Download PDFInfo
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- JP4074437B2 JP4074437B2 JP2001056152A JP2001056152A JP4074437B2 JP 4074437 B2 JP4074437 B2 JP 4074437B2 JP 2001056152 A JP2001056152 A JP 2001056152A JP 2001056152 A JP2001056152 A JP 2001056152A JP 4074437 B2 JP4074437 B2 JP 4074437B2
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
- H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
- H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
- H01F1/34—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials non-metallic substances, e.g. ferrites
- H01F1/342—Oxides
- H01F1/344—Ferrites, e.g. having a cubic spinel structure (X2+O)(Y23+O3), e.g. magnetite Fe3O4
- H01F1/348—Hexaferrites with decreased hardness or anisotropy, i.e. with increased permeability in the microwave (GHz) range, e.g. having a hexagonal crystallographic structure
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Description
【０００１】
【発明の属する技術分野】
本発明は、高周波回路部品用に使用される磁性酸化物焼結体およびそれを用いた高周波回路部品に関する。
【０００２】
【従来の技術】
近年、電子機器の小型化や高周波化に伴い、高周波帯域において高いインダクタンス、インピーダンスを持つ電子部品の需要が高まっている。小型で高いインダクタンス、インピーダンスを得るためには、いわゆる印刷工法やシート工法によって磁性体中に導電体を内蔵した積層構造のコイルを作製することが望ましい。
積層構造とすることでコイルの巻数を多くすることができ、構造も閉磁路となるため高いインダクタンス、インピーダンスが得られる。
【０００３】
焼結体に内蔵される導電体材料としては、電気抵抗率、融点、コストなどの点を考慮して一般に銀（Ａｇ）が多く用いられている。銀の融点は１０００℃以下であるため，積層構造用の磁性体材料としては、従来より一般に、９００℃の焼成でも高い焼結密度が得られるＮｉＺｎ系フェライトが用いられてきた。
【０００４】
しかしながら、ＮｉＺｎ系フェライトは磁気異方性が低いために数百ＭＨｚの周波数で自然共鳴を起こしてしまい、ＧＨｚの周波数帯域で使用することができなかった。
【０００５】
高周波仕様として、非磁性体を用いた空心コイルが用いられることもあるが、非磁性体を用いると高いインダクタンスやインピーダンスを得ることが困難になる。
【０００６】
この一方で六方晶フェライトは、六角板状結晶の面内方向とこの面に垂直な方向とでは磁気的異方性が異なっているため、自然共鳴を起こしにくく、ＧＨｚの周波数帯域まで高い透磁率を持つという特徴をもっている。しかしながら、このものは、所望の焼結密度や磁気特性を得るためには焼成温度を高くする必要がある。
【０００７】
これまで生成温度の高い六方晶フェライトにおいて、低融点酸化物を用いることでＡｇの融点以下で焼成するという試みもなされているが、軟磁性相生成率が低く、六方晶フェライトの磁気特性を十分に発揮することは困難であった。
【０００８】
本願に関連する類似の先行技術の一つに特開平９−１６７７０３号公報がある。当該公報では、Ｚ型六方晶フェライト（Ｂａ，Ｓｒ，Ｐｂ）3（Ｃｏ1-xＣｕx）2Ｆｅ24Ｏ42を中心に検討がなされ、低温焼成を試みるためにＶ2Ｏ5，ＣｕＯ，Ｂｉ2Ｏ3，ＭｏＯ3，ＷＯ3，ＰｂＯの添加を行っている。
【０００９】
また、当該公報においては主要相が、Ｍ型、Ｙ型、Ｗ型、Ｘ型、Ｕ型の六方晶フェライトの低温焼成についても報告がなされている。特に、具体的な実施例で開示されている主要相をＹ型とするもの、すなわち（Ｂａ）2（Ｃｏ1-XＣｕx）2Ｆｅ12Ｏ22については、Ｙ型六方晶フェライトの占有率の記載がなく、不明であるものの、仮焼温度が７００℃と極めて低いために占有率はたかだか５０％程度、添加物を加えればその占有率はさらに低下し、本願のごとく８０％を超えるものではないと言える。そのため、得られる磁気特性は決して満足のいくものではない。すなわち、当該公報における組成および物質の添加は、低温焼結を可能にするが、仮焼き温度の検討が十分になされておらず、焼結後における軟磁性相の生成率が低いために焼成後の磁気特性を十分に発揮することができない。そのため、高いインダクタンスやインピーダンスを得ることが困難であるという問題があると言える。
【００１０】
また、当該公報におけるＣｕＯの含有量も本願と比べて少なく、添加物の効果を考慮したとしても９００℃程度の焼成でＹ型六方晶フェライトの生成率を高めて、高い特性を得ることができないという問題があった。
【００１１】
【発明が解決しようとする課題】
このような実状のもとに本発明は創案されたものであり、その目的は、上記の課題を解決し、数百ＭＨｚ〜ＧＨｚといった高周波帯域まで磁気特性が良好で使用可能であり、かつＹ型六方晶フェライト以外の異相をできるだけ含まず１０００℃以下特に、９００℃付近で焼成可能である磁性酸化物焼結体およびこれを用いた高周波回路部品を提供することにある。
【００１２】
【課題を解決するための手段】
このような課題を解決するために、本発明は、Ｙ型六方晶フェライトで８０％以上占有されてなる磁性酸化物焼結体であって、該磁性酸化物焼結体は、主成分として酸化コバルトをＣｏＯ換算で３〜１５モル％、酸化銅をＣｕＯ換算で５．５〜１７モル％、酸化鉄をＦｅ2Ｏ3換算で５７〜６１モル％、残部をＡＯ（ＡＯは、ＢａＯまたはＳｒＯの少なくとも１種）として含み、副成分として酸化ビスマス（Ｂｉ2Ｏ3）を０．５〜７ｗｔ％を含有し、５００ＭＨｚおよび２ＧＨｚの周波数における透磁率が２．０以上の物性を備えてなるように構成される。
【００１３】
また、本発明は、磁性酸化物焼結体中に導電体が埋設された構造を備える高周波回路部品であって、前記磁性酸化物焼結体は、Ｙ型六方晶フェライトで８０％以上占有され、かつ、該磁性酸化物焼結体は、主成分として酸化コバルトをＣｏＯ換算で３〜１５モル％、酸化銅をＣｕＯ換算で５．５〜１７モル％、酸化鉄をＦｅ2Ｏ3換算で５７〜６１モル％、残部をＡＯ（ＡＯは、ＢａＯまたはＳｒＯの少なくとも１種）として含み、副成分として酸化ビスマス（Ｂｉ2Ｏ3）を０．５〜７ｗｔ％を含有し、５００ＭＨｚおよび２ＧＨｚの周波数における透磁率が２．０以上の物性を備えてなるように構成される。
【００１４】
また、本発明の好ましい態様として、前記磁性酸化物焼結体の製造における仮焼温度は、８５０℃〜１０００℃として構成される。
【００１５】
また、本発明の高周波回路部品の好ましい態様として、前記導電体は、銀（Ａｇ）を主成分としてなるように構成される。
【００１６】
【発明の実施の形態】
以下、本発明の磁性酸化物焼結体について詳細に説明する。
【００１７】
本発明の磁性酸化物焼結体はセラミック焼結体であるために通常のセラミック作製プロセスで製造することができる。
【００１８】
本発明の磁性酸化物焼結体は、主成分として酸化コバルトをＣｏＯ換算で３〜１５モル％（好ましくは、５〜１０モル％）、酸化銅をＣｕＯ換算で５．５〜１７モル％（好ましくは、１０〜１５モル％）、酸化鉄をＦｅ2Ｏ3換算で５７〜６１モル％（好ましくは、５９〜６０モル％）、残部をＡＯ（ＡＯは、ＢａＯまたはＳｒＯの少なくとも１種）として含んでいる。ＡＯの形態は、ＢａＯあるいはＳｒＯの単独形態、またはＢａＯとＳｒＯの混在形態である。
【００１９】
また、本発明の磁性酸化物焼結体は、副成分として酸化ビスマスＢｉ2Ｏ3を０．５〜７ｗｔ％（好ましくは０．６〜５ｗｔ％）、含有している。
【００２０】
このような酸化ビスマスＢｉ2Ｏ3は、後述する実施例からもわかるように添加時に当該酸化物の形態で混入され、焼結後も一般に当該酸化物の形態で残存する。
上記主成分の含有割合において、ＣｏＯが３モル％未満となると、例えば２ＧＨｚにおける透磁率が低下する（例えば２．０未満）という不都合が生じる傾向にあり、ＣｏＯが１５モル％を超えると、例えば５００ＭＨｚにおける透磁率が低下する（例えば２．０未満）という不都合が生じる傾向にある。
【００２１】
また、ＣｕＯが５．５モル％未満となると、仮焼き温度が１０００℃を超えるという不都合が生じる傾向にあり、ＣｕＯが１７モル％を超えると、透磁率が低下する（例えば２．０未満）という不都合が生じる傾向にある。
【００２２】
また、Ｆｅ2Ｏ3が５７モル％未満となったり、Ｆｅ2Ｏ3が６１モル％を超えたりすると透磁率が低下するという不都合が生じる傾向にある。
【００２３】
上記の副成分の含有割合において、上記Ｂｉ2Ｏ3の含有量が０．５ｗｔ％未満となると、１０００℃以下の焼成で理論密度の９０％以上が得られなくなるという不都合が生じる傾向にあり、上記Ｂｉ2Ｏ3の含有量が７ｗｔ％を超えると、透磁率が低下するという不都合が生じる傾向にある。
【００２４】
このようなＢｉ2Ｏ3副成分の添加は、特に、上記のＣｕＯ量の含有と相俟って低温焼結を顕著に実現させることができる。磁気特性向上の相乗効果もある。焼成温度が低くなると、安価で電気抵抗の低いＡｇのような低融点の電極材料を内蔵した形で同時焼成し、電極一体型の閉磁路構成の素子を容易に製造できる。このようにして製造された素子は、例えば、小型でかつ高いＱ値を持つインダクタ、あるいは小型で高周波帯の特に特定周波数でのインピーダンスが大きいノイズフィルター等の高周波素子（高周波回路部品）として利用される。
【００２５】
さらに本発明における磁性酸化物焼結体は、その８０％以上、特に好ましくは、９０％以上がＹ型六方晶フェライトで形成されている。ここに言う「％」は、エックス線回折強度のメインピーク比から算出したものである。
【００２６】
Ｙ型六方晶フェライトの占有割合が８０％未満となると、高周波において高い透磁率を得ることができくなるという不都合が生じる。これにより、高いインダクタンスやインピーダンスを持つ高周波回路部品を得ることが困難となる。
【００２７】
銀（Ａｇ）のような低融点電極材料と同時焼成する場合、本焼成温度が低くなるため、焼結後のＹ型六方晶フェライトを８０％以上とするためには、仮焼時にＹ型六方晶フェライトを８０％以上生成しておく必要がある。組成によって異なるが、８５０℃付近からＢａＦｅ12Ｏ19およびＢａＦｅ2Ｏ4の分解が始まり、Ｙ型六方晶フェライトの生成が始まる。
【００２８】
しかしながら、ＢａＦｅ12Ｏ19およびＢａＦｅ2Ｏ4の分解が十分に進まなければＹ型六方晶フェライトの生成が進まない。従って、Ｙ型六方晶フェライトを８０％以上とするために、仮焼温度を８５０℃以上、特に、８５０〜１０００℃とする必要がある。さらに、ＣｕＯ量を５．５〜１７モル％含有させることが必要となる。仮焼温度が８５０℃未満となったり、ＣｕＯ量が上記の範囲を外れると、８０％を超えるＹ型六方晶フェライトの生成が困難となる。また、仮焼き温度が１０００℃を超えて高くなり過ぎると、細かい粉砕粉が得られなくなってしまう。細かい粉砕粉の作製は、低温焼成には極めて重要な技術である。
【００２９】
このような観点から、上述のごとく仮焼温度を８５０〜１０００℃において、Ｙ型六方晶フェライトの生成率を高くするためには、主成分としての前記ＣｕＯ量を５．５〜１７モル％含有させることが必要となる。
【００３０】
このような本発明における磁性酸化焼結体は、磁性酸化物焼結体中に導電体が埋設された構造を備える高周波回路部品、例えば、インピーダ、インダクタとして用いられる。
【００３１】
【実施例】
以下、具体的実施例を挙げて本発明をさらに詳細に説明する。
【００３２】
[実験例Ｉ]
（実施例サンプルおよび比較例サンプルの作製）
焼結後の組成が下記表１に示すような組成となるように各原料を秤量し、鋼鉄製ボールミルで１５時間湿式混合した。次に、この混合粉を大気中、表１に記載された温度で２時間仮焼きした。次いで、表１に示されるごとく副成分としてＢｉ2Ｏ3を所定量添加した後、鉄鋼製ボールミルで１５時間粉砕した。
【００３３】
このようにして得られた六方晶フェライト粉を造粒して、１００ＭＰａの圧力で所望の形状に成形した。
【００３４】
この成形体を大気中、表１に示される焼成温度で２時間焼結した。六方晶フェライト焼結体の組成は下記表１に示すとおりであり、これらの各サンプルについて、密度、並びに２５℃における周波数５００ＭＨｚおよび２ＧＨｚの透磁率をそれぞれ測定して表１に示した。透磁率は周波数５００ＭＨｚおよび２ＧＨｚの周波数において、それぞれ２．０以上の値を目標としている。
【００３５】
なお、Ｙ型六方晶フェライトによる占有率は、焼結体の粉砕粉を用いて、Ｘ線回折ピークの強度比より算出した。
【００３６】
【表１】
[実験例II]
次に、本発明の磁性体を用いてインピーダンス素子を作製した。すなわち、焼結後の組成が上記表１の実施例７サンプルに示されるような組成となるように各原料を秤量し、鋼鉄製ボールミルで１５時間湿式混合した。次に、この混合粉を大気中、９５０℃で２時間仮焼きした。次いで、副成分としてＢｉ2Ｏ3を５ｗｔ％添加した後、鉄鋼製ボールミルで１５時間粉砕した。
【００３８】
この仮焼き粉末に有機バインダーを混合し、ドクターブレード法により均一なグリーンシートを形成した。
【００３９】
比較のためにＮｉＣｕＺｎ系スピネルフェライト粉末（ＮｉＯ＝４５モル％、ＣｕＯ＝５モル％、ＺｎＯ＝１．５モル％、Ｆｅ2Ｏ3＝４８モル％、ＣｏＯ＝０．５モル％）を用いて作製したグリーンシートも準備した。
【００４０】
この一方で、銀を混合してなる導電性ペーストを用意し、先のグリーンシート上にコイルをスパイラル状となるように積層した。厚み方向に圧力を加えて圧着し、磁性体に電極がサンドイッチされたグリーンシート積層体を作製した。これを９３０℃で２時間焼成した。得られた焼結体の側面の内部導電体の位置に銀ペーストを塗布し、外部電極を焼き付け、図１に概略的に示されるインピーダンス素子（高周波回路部品）とした。なお、図１は素子内部構造の理解を容易にするためにモデル図として描かれている。図１において、符号１１はインナーコンダクタ（Ａｇコイル）であり、符号１０はターミナルコンダクタであり、符号２０はフェライトを示している。
【００４１】
このようにして得られたインピーダンス素子のインピーダンスおよび透磁率を周波数２ＧＨｚで測定したところ、従来のＮｉＣｕＺｎ系スピネルフェライトではインピーダンスが１３５Ω（透磁率は１．２）であったのに対して、本発明のものではインピーダンスが２０８Ω（透磁率は３．７）と約５４％以上改善されていた。
【００４２】
【発明の効果】
上記の結果より本発明の効果は明らかである。すなわち、本発明は、Ｙ型六方晶フェライトで８０％以上占有されてなる磁性酸化物焼結体であって、該磁性酸化物焼結体は、主成分として酸化コバルトをＣｏＯ換算で３〜１５モル％、酸化銅をＣｕＯ換算で５．５〜１７モル％、酸化鉄をＦｅ2Ｏ3換算で５７〜６１モル％、残部をＡＯ（ＡＯは、ＢａＯまたはＳｒＯの少なくとも１種）として含み、副成分として酸化ビスマス（Ｂｉ2Ｏ3）を０．５〜７ｗｔ％を含有してなるように構成されているので、数百ＭＨｚ〜ＧＨｚといった高周波帯域まで磁気特性が良好で使用可能であり、かつＹ型六方晶フェライト以外の異相をできるだけ含まず１０００℃以下特に、９００℃付近で焼成可能である磁性酸化物焼結体およびこれを用いた高周波回路部品を提供することができる。
【図面の簡単な説明】
【図１】実施例で用いたインダクタンス素子（高周波回路部品）の概略図面である。
【符号の説明】
１０…ターミナルコンダクタ
１１…インナーコンダクタ
２０…フェライト[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a magnetic oxide sintered body used for a high-frequency circuit component and a high-frequency circuit component using the same.
[0002]
[Prior art]
In recent years, with the miniaturization and high frequency of electronic devices, there is an increasing demand for electronic components having high inductance and impedance in a high frequency band. In order to obtain a small and high inductance and impedance, it is desirable to produce a coil having a laminated structure in which a conductor is incorporated in a magnetic material by a so-called printing method or sheet method.
With the laminated structure, the number of turns of the coil can be increased, and the structure also becomes a closed magnetic circuit, so that high inductance and impedance can be obtained.
[0003]
In general, silver (Ag) is often used as a conductive material incorporated in the sintered body in consideration of electrical resistivity, melting point, cost, and the like. Since the melting point of silver is 1000 ° C. or lower, NiZn-based ferrite that can obtain a high sintered density even when fired at 900 ° C. has been generally used as a magnetic material for a laminated structure.
[0004]
However, since NiZn ferrite has low magnetic anisotropy, it causes natural resonance at a frequency of several hundred MHz and cannot be used in the GHz frequency band.
[0005]
As a high-frequency specification, an air-core coil using a nonmagnetic material may be used. However, when a nonmagnetic material is used, it is difficult to obtain high inductance and impedance.
[0006]
On the other hand, since hexagonal ferrite has different magnetic anisotropy in the in-plane direction of the hexagonal plate crystal and the direction perpendicular to this plane, it does not easily cause natural resonance and has high magnetic permeability up to the GHz frequency band. It has the characteristic of having. However, this requires a high firing temperature in order to obtain a desired sintered density and magnetic properties.
[0007]
Up to now, attempts have been made to fire hexagonal ferrite with a high production temperature below the melting point of Ag by using a low melting point oxide, but the soft magnetic phase formation rate is low and the magnetic properties of hexagonal ferrite are sufficient. It was difficult to demonstrate.
[0008]
One similar prior art related to the present application is JP-A-9-167703. In this publication, Z-type hexagonal ferrite (Ba, Sr, Pb) 3 (Co 1-x Cu x ) 2 Fe 24 O 42 is mainly studied, and V 2 O 5 , CuO, Bi 2 O 3 , MoO 3 , WO 3 and PbO are added.
[0009]
In this publication, the main phase is also reported for low-temperature firing of M-type, Y-type, W-type, X-type, and U-type hexagonal ferrites. In particular, in the case where the main phase disclosed in the specific example is Y-type, that is, (Ba) 2 (Co 1-X Cu x ) 2 Fe 12 O 22 , the occupation ratio of Y-type hexagonal ferrite Although there is no description and is unknown, the calcination temperature is extremely low at 700 ° C, so the occupancy rate is at most about 50%. If an additive is added, the occupancy rate is further reduced and exceeds 80% as in this application. Not so. Therefore, the magnetic properties obtained are never satisfactory. That is, the composition and addition of substances in the publication allow low-temperature sintering, but the calcining temperature has not been sufficiently studied, and the rate of formation of the soft magnetic phase after sintering is low. The magnetic properties cannot be fully exhibited. Therefore, it can be said that there is a problem that it is difficult to obtain high inductance and impedance.
[0010]
In addition, the content of CuO in the publication is small compared to the present application, and even if the effect of the additive is taken into consideration, the yield of Y-type hexagonal ferrite can be increased by firing at about 900 ° C. and high characteristics cannot be obtained. There was a problem.
[0011]
[Problems to be solved by the invention]
The present invention has been devised based on such a situation, and its purpose is to solve the above-mentioned problems and to have good magnetic properties up to a high frequency band such as several hundred MHz to GHz and to be usable. An object of the present invention is to provide a magnetic oxide sintered body that does not contain foreign phases other than type hexagonal ferrite as much as possible and can be fired at 1000 ° C. or less, particularly near 900 ° C., and a high-frequency circuit component using the same.
[0012]
[Means for Solving the Problems]
In order to solve such problems, the present invention provides a magnetic oxide sintered body that is occupied by 80% or more of Y-type hexagonal ferrite, and the magnetic oxide sintered body is oxidized as a main component. Cobalt is 3 to 15 mol% in terms of CoO, copper oxide is 5.5 to 17 mol% in terms of CuO, iron oxide is 57 to 61 mol% in terms of Fe 2 O 3 , and the balance is AO (AO is BaO or SrO) And at least one kind of bismuth oxide (Bi 2 O 3 ) as a subcomponent and containing 0.5 to 7 wt% of magnetic properties at a frequency of 500 MHz and 2 GHz of 2.0 or more. Configured.
[0013]
The present invention is a high-frequency circuit component having a structure in which a conductor is embedded in a magnetic oxide sintered body, and the magnetic oxide sintered body is occupied by Y-type hexagonal ferrite by 80% or more. and magnetic sintered oxide, cobalt oxide as the main component 3-15 mol% in terms of CoO, 5.5 to 17 mol% of copper oxide in terms of CuO, an iron oxide in terms of Fe 2 O 3 57 to 61 mol%, the balance is contained as AO (AO is at least one of BaO or SrO), bismuth oxide (Bi 2 O 3 ) is contained as an accessory component in an amount of 0.5 to 7 wt% , 500 MHz and 2 GHz The magnetic permeability at the frequency is configured to have a physical property of 2.0 or more .
[0014]
As a preferred embodiment of the present invention, the calcining temperature in the production of the magnetic oxide sintered body is configured as 850 ° C. to 1000 ° C.
[0015]
Moreover, as a preferable aspect of the high-frequency circuit component of the present invention, the conductor is configured to have silver (Ag) as a main component.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the magnetic oxide sintered body of the present invention will be described in detail.
[0017]
Since the magnetic oxide sintered body of the present invention is a ceramic sintered body, it can be produced by an ordinary ceramic production process.
[0018]
In the magnetic oxide sintered body of the present invention, cobalt oxide as a main component is 3 to 15 mol% (preferably 5 to 10 mol%) in terms of CoO, and copper oxide is 5.5 to 17 mol% in terms of CuO ( preferably, 10 to 15 mol%), the iron oxide 57-61 mole% calculated as Fe 2 O 3 (preferably, 59-60 mol%), the remainder AO (AO is at least one of BaO or SrO) Includes as. The form of AO is a single form of BaO or SrO, or a mixed form of BaO and SrO.
[0019]
Moreover, the magnetic oxide sintered body of the present invention contains 0.5 to 7 wt% (preferably 0.6 to 5 wt%) of bismuth oxide Bi 2 O 3 as a subcomponent.
[0020]
Such bismuth oxide Bi 2 O 3 is mixed in the form of the oxide at the time of addition, as will be understood from Examples described later, and generally remains in the form of the oxide even after sintering.
If the CoO content is less than 3 mol% in the content ratio of the main component, there is a tendency that, for example, the permeability at 2 GHz is reduced (for example, less than 2.0), and when CoO exceeds 15 mol%, for example, There is a tendency for the inconvenience that the magnetic permeability at 500 MHz decreases (for example, less than 2.0).
[0021]
Further, when CuO is less than 5.5 mol%, there is a tendency that the calcining temperature exceeds 1000 ° C., and when CuO exceeds 17 mol%, the magnetic permeability decreases (for example, less than 2.0). The inconvenience tends to occur.
[0022]
Further, when Fe 2 O 3 is less than 57 mol% or Fe 2 O 3 exceeds 61 mol%, there is a tendency that the magnetic permeability is lowered.
[0023]
In the content ratio of the subcomponent, when the content of Bi 2 O 3 is less than 0.5 wt%, there is a tendency that 90% or more of the theoretical density cannot be obtained by firing at 1000 ° C. or less, When the content of Bi 2 O 3 exceeds 7 wt%, there is a tendency for the disadvantage that the magnetic permeability is lowered.
[0024]
Addition of such a Bi 2 O 3 subcomponent can realize remarkably low temperature sintering, especially in combination with the above-mentioned CuO content. There is also a synergistic effect of improving magnetic properties. When the firing temperature is lowered, it is possible to easily produce an element with an integrated electrode and a closed magnetic circuit structure by simultaneously firing in a form incorporating a low melting point electrode material such as Ag having low electric resistance. The element manufactured in this way is used as, for example, a high-frequency element (high-frequency circuit component) such as a small-sized inductor having a high Q value, or a noise filter having a small impedance and high impedance in a specific frequency in a high-frequency band. The
[0025]
Further, 80% or more, particularly preferably 90% or more, of the magnetic oxide sintered body in the present invention is formed of Y-type hexagonal ferrite. Here, “%” is calculated from the main peak ratio of X-ray diffraction intensity.
[0026]
When the occupation ratio of the Y-type hexagonal ferrite is less than 80%, there is a disadvantage that it becomes difficult to obtain a high magnetic permeability at a high frequency. This makes it difficult to obtain a high-frequency circuit component having high inductance and impedance.
[0027]
In the case of co-firing with a low melting point electrode material such as silver (Ag), the main firing temperature is lowered. Therefore, in order to make the Y-type hexagonal ferrite after sintering 80% or more, It is necessary to produce 80% or more of crystal ferrite. Although it depends on the composition, decomposition of BaFe 12 O 19 and BaFe 2 O 4 starts from around 850 ° C., and generation of Y-type hexagonal ferrite begins.
[0028]
However, if the decomposition of BaFe 12 O 19 and BaFe 2 O 4 does not proceed sufficiently, the production of Y-type hexagonal ferrite will not proceed. Therefore, in order to make the Y-type hexagonal ferrite 80% or more, the calcining temperature needs to be 850 ° C. or more, particularly 850 to 1000 ° C. Furthermore, it is necessary to contain 5.5 to 17 mol% of the CuO amount. When the calcining temperature is less than 850 ° C. or the CuO amount is out of the above range, it is difficult to produce Y-type hexagonal ferrite exceeding 80%. On the other hand, if the calcining temperature exceeds 1000 ° C. and becomes too high, fine pulverized powder cannot be obtained. Production of fine pulverized powder is an extremely important technique for low-temperature firing.
[0029]
From such a viewpoint, as described above, at a calcining temperature of 850 to 1000 ° C., in order to increase the yield of Y-type hexagonal ferrite, the CuO content as a main component is contained in an amount of 5.5 to 17 mol%. It is necessary to make it.
[0030]
Such a magnetic oxidation sintered body in the present invention is used as a high-frequency circuit component having a structure in which a conductor is embedded in a magnetic oxide sintered body, for example, an impedancer or an inductor.
[0031]
【Example】
Hereinafter, the present invention will be described in more detail with reference to specific examples.
[0032]
[Experimental Example I]
(Production of Example Sample and Comparative Example Sample)
Each raw material was weighed so that the composition after sintering was as shown in Table 1 below, and wet mixed in a steel ball mill for 15 hours. Next, this mixed powder was calcined in the atmosphere at the temperature described in Table 1 for 2 hours. Next, as shown in Table 1, a predetermined amount of Bi 2 O 3 was added as an auxiliary component, and then pulverized with a steel ball mill for 15 hours.
[0033]
The hexagonal ferrite powder thus obtained was granulated and formed into a desired shape at a pressure of 100 MPa.
[0034]
The molded body was sintered in the atmosphere at the firing temperature shown in Table 1 for 2 hours. The composition of the hexagonal ferrite sintered body is as shown in Table 1 below. The density and the permeability at frequencies of 500 MHz and 2 GHz at 25 ° C. were measured for each of these samples and shown in Table 1. The magnetic permeability targets a value of 2.0 or more at frequencies of 500 MHz and 2 GHz, respectively.
[0035]
In addition, the occupation rate by the Y-type hexagonal ferrite was calculated from the intensity ratio of the X-ray diffraction peak using the pulverized powder of the sintered body.
[0036]
[Table 1]
[Experimental example II]
Next, an impedance element was produced using the magnetic material of the present invention. That is, each raw material was weighed so that the composition after sintering was as shown in the sample of Example 7 in Table 1 above, and wet-mixed for 15 hours in a steel ball mill. Next, this mixed powder was calcined at 950 ° C. for 2 hours in the air. Next, 5 wt% of Bi 2 O 3 was added as an accessory component, and then pulverized with a steel ball mill for 15 hours.
[0038]
An organic binder was mixed with the calcined powder, and a uniform green sheet was formed by a doctor blade method.
[0039]
For comparison, NiCuZn spinel ferrite powder (NiO = 45 mol%, CuO = 5 mol%, ZnO = 1.5 mol%, Fe 2 O 3 = 48 mol%, CoO = 0.5 mol%) was used. A prepared green sheet was also prepared.
[0040]
On the other hand, a conductive paste formed by mixing silver was prepared, and the coil was laminated on the previous green sheet so as to have a spiral shape. Pressure was applied in the thickness direction and pressure bonded to produce a green sheet laminate in which electrodes were sandwiched between magnetic materials. This was calcined at 930 ° C. for 2 hours. Silver paste was applied to the position of the internal conductor on the side surface of the obtained sintered body, and the external electrode was baked to obtain an impedance element (high-frequency circuit component) schematically shown in FIG. FIG. 1 is drawn as a model diagram for easy understanding of the internal structure of the element. In FIG. 1,
[0041]
When the impedance and magnetic permeability of the impedance element thus obtained were measured at a frequency of 2 GHz, the impedance of the conventional NiCuZn spinel ferrite was 135Ω (the magnetic permeability was 1.2), whereas the present invention Impedance was 208Ω (permeability is 3.7), an improvement of about 54% or more.
[0042]
【The invention's effect】
The effects of the present invention are clear from the above results. That is, the present invention is a magnetic oxide sintered body that is 80% or more occupied by Y-type hexagonal ferrite, and the magnetic oxide sintered body contains cobalt oxide as a main component in an amount of 3 to 15 in terms of CoO. Mol%, copper oxide 5.5 to 17 mol% in terms of CuO, iron oxide 57 to 61 mol% in terms of Fe 2 O 3 , and the remainder as AO (AO is at least one of BaO or SrO), Since it is configured to contain 0.5 to 7 wt% of bismuth oxide (Bi 2 O 3 ) as a subcomponent, it can be used with good magnetic properties up to a high frequency band of several hundred MHz to GHz, In addition, it is possible to provide a magnetic oxide sintered body that does not contain foreign phases other than Y-type hexagonal ferrite as much as possible and can be fired at 1000 ° C. or less, particularly near 900 ° C., and a high-frequency circuit component using the same.
[Brief description of the drawings]
FIG. 1 is a schematic drawing of an inductance element (high frequency circuit component) used in an example.
[Explanation of symbols]
10 ...
Claims (5)
該磁性酸化物焼結体は、主成分として酸化コバルトをＣｏＯ換算で３〜１５モル％、酸化銅をＣｕＯ換算で５．５〜１７モル％、酸化鉄をＦｅ2Ｏ3換算で５７〜６１モル％、残部をＡＯ（ＡＯは、ＢａＯまたはＳｒＯの少なくとも１種）として含み、
副成分として酸化ビスマス（Ｂｉ2Ｏ3）を０．５〜７ｗｔ％を含有し、
５００ＭＨｚおよび２ＧＨｚの周波数における透磁率が２．０以上の物性を備えてなることを特徴とする磁性酸化物焼結体。A magnetic oxide sintered body occupied by 80% or more of Y-type hexagonal ferrite,
In the magnetic oxide sintered body, cobalt oxide as a main component is 3 to 15 mol% in terms of CoO, copper oxide is 5.5 to 17 mol% in terms of CuO, and iron oxide is 57 to 61 in terms of Fe 2 O 3. Mol%, and the balance as AO (AO is at least one of BaO or SrO),
Containing 0.5 to 7 wt% of bismuth oxide (Bi 2 O 3 ) as an accessory component ,
A magnetic oxide sintered body having a physical property of magnetic permeability of 2.0 or more at frequencies of 500 MHz and 2 GHz .
前記磁性酸化物焼結体は、Ｙ型六方晶フェライトで８０％以上占有され、かつ、
該磁性酸化物焼結体は、主成分として酸化コバルトをＣｏＯ換算で３〜１５モル％、酸化銅をＣｕＯ換算で５．５〜１７モル％、酸化鉄をＦｅ2Ｏ3換算で５７〜６１モル％、残部をＡＯ（ＡＯは、ＢａＯまたはＳｒＯの少なくとも１種）として含み、
副成分として酸化ビスマス（Ｂｉ2Ｏ3）を０．５〜７ｗｔ％を含有し、
５００ＭＨｚおよび２ＧＨｚの周波数における透磁率が２．０以上の物性を備えてなることを特徴とする高周波回路部品。A high-frequency circuit component having a structure in which a conductor is embedded in a magnetic oxide sintered body,
The magnetic oxide sintered body is occupied by 80% or more of Y-type hexagonal ferrite, and
In the magnetic oxide sintered body, cobalt oxide as a main component is 3 to 15 mol% in terms of CoO, copper oxide is 5.5 to 17 mol% in terms of CuO, and iron oxide is 57 to 61 in terms of Fe 2 O 3. Mol%, and the balance as AO (AO is at least one of BaO or SrO),
Containing 0.5 to 7 wt% of bismuth oxide (Bi 2 O 3 ) as an accessory component ,
A high-frequency circuit component comprising a physical property having a magnetic permeability of 2.0 or more at frequencies of 500 MHz and 2 GHz .
Priority Applications (8)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001056152A JP4074437B2 (en) | 2001-03-01 | 2001-03-01 | Magnetic oxide sintered body and high-frequency circuit component using the same |
| PCT/JP2001/006691 WO2002070432A1 (en) | 2001-03-01 | 2001-08-03 | Magnetic oxide sinter and high-frequency circuit part employing the same |
| CNB018087744A CN1232471C (en) | 2001-03-01 | 2001-08-03 | Magnetic oxide sinter and high frequency circuit part employing same |
| DE60136223T DE60136223D1 (en) | 2001-03-01 | 2001-08-03 | SINTERED MAGNETIC OXIDE AND HIGH FREQUENCY CIRCUIT UNIT USING THIS |
| US10/070,706 US6660179B2 (en) | 2001-03-01 | 2001-08-03 | Sintered body and high-frequency circuit component |
| KR10-2001-7016331A KR100423961B1 (en) | 2001-03-01 | 2001-08-03 | Sintered body and high-frequency circuit component |
| EP01954432A EP1364927B1 (en) | 2001-03-01 | 2001-08-03 | Magnetic oxide sinter and high-frequency circuit part employing the same |
| TW90119381A TW572864B (en) | 2001-03-01 | 2001-08-08 | Magnetic oxide sinter and high-frequency circuit part employing the same |
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| JP2001056152A JP4074437B2 (en) | 2001-03-01 | 2001-03-01 | Magnetic oxide sintered body and high-frequency circuit component using the same |
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| WO2007148438A1 (en) * | 2006-06-21 | 2007-12-27 | Hitachi Metals, Ltd. | Magnetic material antenna and ferrite sinter |
| JP5311183B2 (en) * | 2008-01-17 | 2013-10-09 | 日立金属株式会社 | Ferrite sintered body and magnetic antenna |
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| JPH09129433A (en) * | 1995-10-31 | 1997-05-16 | Tokin Corp | Soft magnetic hexagonal ferrite |
| JP3693398B2 (en) * | 1995-12-15 | 2005-09-07 | 松下電器産業株式会社 | Ceramic magnetic material and high frequency circuit component using the same |
| JPH09246031A (en) * | 1996-03-11 | 1997-09-19 | Osamu Kimura | Magnetic material for high frequency |
| JP3683680B2 (en) * | 1997-05-30 | 2005-08-17 | 東光株式会社 | Magnetic material for high frequency multilayer inductors |
| JP3939476B2 (en) * | 1999-01-18 | 2007-07-04 | 東光株式会社 | High frequency magnetic materials |
| JP3735228B2 (en) * | 1999-03-09 | 2006-01-18 | Ｔｄｋ株式会社 | Method for producing soft magnetic ferrite powder and method for producing multilayer chip inductor |
| JP3457576B2 (en) * | 1999-06-23 | 2003-10-20 | 修 木村 | Magnetic material for high frequency |
| JP4069284B2 (en) * | 2001-02-23 | 2008-04-02 | Ｔｄｋ株式会社 | Magnetic ferrite materials and multilayer ferrite parts |
| JP2002015913A (en) * | 2000-04-28 | 2002-01-18 | Tdk Corp | Magnetic ferrite powder, magnetic ferrite sintered body, laminated ferrite part and its manufacturing method |
| JP2002068830A (en) * | 2000-09-01 | 2002-03-08 | Murata Mfg Co Ltd | Hexagonal y type oxide magnetic material and inductor element |
| JP4683174B2 (en) * | 2001-02-14 | 2011-05-11 | 戸田工業株式会社 | Soft magnetic sheet |
| JP2004143042A (en) * | 2003-12-16 | 2004-05-20 | Matsushita Electric Ind Co Ltd | Magnetic material for micro wave, manufacturing method therefor, and high-frequency circuit parts |
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