JP2006137653A - Hexagonal magnetoplumbite-type ferrite and electromagnetic wave absorber using the same - Google Patents
Hexagonal magnetoplumbite-type ferrite and electromagnetic wave absorber using the same Download PDFInfo
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本発明は、ＧＨｚ帯域用の電波吸収体に適したマグネトプランバイト型六方晶フェライト、およびそれを用いた電波吸収体に関する。 The present invention relates to a magnetoplumbite type hexagonal ferrite suitable for a radio wave absorber for the GHz band, and a radio wave absorber using the same.
近年、情報通信技術の高度化に伴い、ＧＨｚ帯域の電波が種々の用途で使用されるようになってきた。例えば、携帯電話、無線ＬＡＮ、衛生放送、高度道路交通システム、ノンストップ自動料金徴収システム（ＥＴＣ）、自動車走行支援システム（ＡＨＳ）などが挙げられる。このように高周波域での電波利用形態が多様化すると、電子部品同士の干渉による故障、誤動作、機能不全などが懸念され、その対策が重要となってくる。その１つとして、電波吸収体を用いて不要な電波を吸収し、電波の反射および侵入を防ぐ方法が有効である。昨今、ＧＨｚ帯域用の電波吸収体は需要が増大しつつある。 In recent years, with the advancement of information communication technology, radio waves in the GHz band have been used for various purposes. For example, a mobile phone, wireless LAN, sanitary broadcasting, intelligent road traffic system, non-stop automatic toll collection system (ETC), automobile driving support system (AHS), and the like can be mentioned. Thus, when radio wave usage forms in a high frequency range are diversified, there is a concern about failure, malfunction, malfunction or the like due to interference between electronic components, and countermeasures are important. As one of them, a method of absorbing unnecessary radio waves using a radio wave absorber and preventing reflection and intrusion of radio waves is effective. Recently, the demand for radio wave absorbers for the GHz band is increasing.
従来、高周波帯域用の電波吸収体には、主としてフェライト等の酸化物系磁性材料が多く用いられている。フェライトの中でも、ＭＨｚ帯域では主としてスピネル系のものが使用されるが、ＧＨｚ以上の高周波帯域において優れた特性を発揮するものとしてマグネトプランバイト型六方晶フェライトが有望視されており、例えばＦe3+の一部を４価の陽イオンと２価の陽イオンで置換したマグネトプランバイト型六方晶フェライトが知られている（特許文献１、非特許文献１）。
Conventionally, oxide-based magnetic materials such as ferrite are often used for radio wave absorbers for high frequency bands. Among ferrites, spinel type is mainly used in the MHz band, but magnetoplumbite type hexagonal ferrite is promising as a material that exhibits excellent characteristics in a high frequency band of GHz or higher. For example, Fe 3+ There is known a magnetoplumbite type hexagonal ferrite in which a part of is substituted with a tetravalent cation and a divalent cation (
フェライトを用いた電波吸収体は「インピーダンス整合型」であり、材料定数が定まると整合周波数と整合厚さが決定される。発明者らは、Ｆe3+の一部を置換したタイプのマグネトプランバイト型六方晶フェライトを用いた電波吸収体について、電波吸収特性を種々調査してきた。その結果、この種の電波吸収体の場合、厚さによる整合周波数の変化が大きいことが明らかになった。すなわち、シート厚さが変動すると整合周波数が大きく変化してしまうため、厚さの微妙な違いによって目的周波数領域の電波が的確に吸収できないといった問題が生じやすい。つまり、工業生産において安定した品質を得るためには、厚さについて高い寸法精度が要求され、これは生産コストを増大させる一因となる。 A radio wave absorber using ferrite is an “impedance matching type”, and when a material constant is determined, a matching frequency and a matching thickness are determined. The inventors have investigated various radio wave absorption characteristics of a radio wave absorber using a magnetoplumbite type hexagonal ferrite in which a part of Fe 3+ is substituted. As a result, in the case of this type of wave absorber, it became clear that the change of the matching frequency with the thickness is large. That is, when the sheet thickness varies, the matching frequency changes greatly, and a problem that radio waves in the target frequency region cannot be accurately absorbed due to a subtle difference in thickness tends to occur. That is, in order to obtain stable quality in industrial production, high dimensional accuracy is required for the thickness, which contributes to an increase in production cost.
本発明はこのような問題に鑑み、電波吸収体に使用したとき、その厚さが変動しても整合周波数が変化しにくい性質を発揮するマグネトプランバイト型六方晶フェライトを開発し提供しようというものである。 In view of these problems, the present invention intends to develop and provide a magnetoplumbite type hexagonal ferrite that exhibits the property that the matching frequency hardly changes even when the thickness of the absorber is changed. It is.
上記目的は、組成式ＡＦe(12-x)(Ｂ10.5Ｂ20.5)xＯ19で表され、ＡはＢa、Ｓrの１種または２種、Ｂ1はＴi、Ｚrの１種または２種、Ｂ2は２価金属元素であり、Ｂ2としてＣo、Ｍn、Ｃu、Ｍg、Ｚn、Ｎiのうち２種以上を含有するマグネトプランバイト型六方晶フェライトによって達成される。上記Ｂ2として少なくともＺnを含有し、特にＣoとＺn、あるいはＭnとＺnを含有するものが好適な対象となる。 The object is represented by the composition formula AFe (12-x) (B1 0.5 B2 0.5 ) x O 19 , A is one or two of Ba and Sr, B1 is one or two of Ti and Zr, B2 Is a divalent metal element, and is achieved by a magnetoplumbite type hexagonal ferrite containing two or more of Co, Mn, Cu, Mg, Zn, Ni as B2. B2 contains at least Zn, particularly those containing Co and Zn, or Mn and Zn.
具体的には、例えば以下のi)ii)に示すものが挙げられる。
i) 組成式ＡＦe(12-x)(Ｂ10.5(Ｃo(1-y)Ｚny)0.5)xＯ19で表され、ＡはＢa、Ｓrの１種または２種、Ｂ1はＴi、Ｚrの１種または２種であり、ｘは１.８〜３.０、ｙは０.２〜０.８であるマグネトプランバイト型六方晶フェライト。
ii) 組成式ＡＦe(12-x)(Ｂ10.5(Ｍn(1-y)Ｚny)0.5)xＯ19で表され、ＡはＢa、Ｓrの１種または２種、Ｂ1はＴi、Ｚrの１種または２種であり、ｘは３.６〜４.８、ｙは０.５±０.１であるマグネトプランバイト型六方晶フェライト。
Specific examples include the following i) ii).
i) represented by the composition formula AFe (12-x) (B1 0.5 (Co (1-y) Zn y ) 0.5 ) x O 19 , A is one or two of Ba and Sr, B1 is Ti and Zr Magnetoplumbite type hexagonal ferrite, which is one or two, x is 1.8 to 3.0, and y is 0.2 to 0.8.
ii) represented by the composition formula AFe (12-x) (B1 0.5 (Mn (1-y) Zn y ) 0.5 ) x O 19 , A is one or two of Ba and Sr, B1 is Ti and Zr Magnetoplumbite type hexagonal ferrite, which is one or two, x is 3.6 to 4.8, and y is 0.5 ± 0.1.
また本発明では、上記のマグネトプランバイト型六方晶フェライトの粉末を用いた電波吸収体が提供される。 The present invention also provides a radio wave absorber using the above-described magnetoplumbite type hexagonal ferrite powder.
本発明によれば、マグネトプランバイト型六方晶フェライトにおいて、電波吸収体の厚さ変動による整合周波数の変化を小さく抑えたものが提供可能になった。この改良されたマグネトプランバイト型六方晶フェライトを用いると、電波吸収体の製造において、従来ほど厳格な厚さの寸法精度を要求しなくても、所定周波数領域に対する優れた電波吸収性能を安定して得ることができる。また、厚さが変動しやすい塗料や射出成形品においても、整合周波数を所望の周波数領域に合致させることが容易になる。したがって本発明は、マグネトプランバイト型六方晶フェライトを用いた電波吸収体の工業生産コスト低減により、その普及に寄与し、ひいてはＧＨｚ帯域の電波障害防止に貢献するものである。 According to the present invention, it is possible to provide magnetoplumbite type hexagonal ferrite in which a change in matching frequency due to a thickness variation of a radio wave absorber is suppressed to be small. Using this improved magnetoplumbite-type hexagonal ferrite, stable radio wave absorption performance in a specified frequency range can be stabilized without requiring strict dimensional accuracy as in the conventional manufacturing of radio wave absorbers. Can be obtained. In addition, it becomes easy to match the matching frequency to a desired frequency region even in a paint or injection molded product whose thickness is likely to fluctuate. Therefore, the present invention contributes to the spread of the radio wave absorber using magnetoplumbite type hexagonal ferrite by reducing the industrial production cost, and further contributes to prevention of radio wave interference in the GHz band.
本発明では、Ｆe3+の一部を他の元素で置換したマグネトプランバイト型六方晶フェライトのうち、以下の組成式で表されるものを対象とする。
ＡＦe(12-x)(Ｂ10.5Ｂ20.5)xＯ19
ここで、ＡはＢa、Ｓrの１種または２種、Ｂ1はＴi、Ｚrの１種または２種、Ｂ2は２価金属元素である。
ただし本発明では、上記組成式のＢ2元素として、Ｃo、Ｍn、Ｃu、Ｍg、Ｚn、Ｎiのうち２種以上を含有させる。このとき、電波吸収体の厚さ変動による整合周波数の変化を顕著に減少させることができるのである。その理由は現時点で不明な点も多いが、多種元素を複合添加することで結晶歪が小さくなり、結晶構造上安定してくることによって、その歪に起因する周波数変動がより小さく抑えられることが考えられる。
In the present invention, among the magnetoplumbite type hexagonal ferrites in which part of Fe 3+ is substituted with another element, the one represented by the following composition formula is used.
AFe (12-x) (B1 0.5 B2 0.5 ) x O 19
Here, A is one or two of Ba and Sr, B1 is one or two of Ti and Zr, and B2 is a divalent metal element.
However, in the present invention, two or more of Co, Mn, Cu, Mg, Zn and Ni are contained as the B2 element in the composition formula. At this time, the change of the matching frequency due to the thickness variation of the radio wave absorber can be remarkably reduced. The reason for this is not clear at this point, but the addition of multiple elements reduces the crystal strain and stabilizes the crystal structure, which can reduce the frequency fluctuations caused by the strain. Conceivable.
その実用的な組成を例示すると、例えばＢ2元素としてＣoとＺnを複合添加した組成式ＢaＦe(12-x)(Ｔi0.5(Ｃo(1-y)Ｚny)0.5)xＯ19で表されるものが挙げられる。検討の結果、ＣoとＺnのモル比については少なくとも上記ｙが０.２〜０.８の範囲で厚さによる整合周波数の変化が顕著に減少する効果が得られる。ｙは０.３〜０.８の範囲とすることが好ましく、０.４〜０.８の範囲で特に大きな効果が得られる。置換量ｘにより吸収周波数領域をコントロールすることができ、例えばｘは１.８〜３.０の範囲とすることができる。 An example of its practical composition is represented by the composition formula BaFe (12-x) (Ti 0.5 (Co (1-y) Zn y ) 0.5 ) x O 19 in which Co and Zn are added as B2 elements. Things. As a result of the study, the molar ratio of Co and Zn has an effect that the change of the matching frequency due to the thickness is remarkably reduced at least when y is in the range of 0.2 to 0.8. y is preferably in the range of 0.3 to 0.8, and a particularly large effect is obtained in the range of 0.4 to 0.8. The absorption frequency region can be controlled by the substitution amount x. For example, x can be in the range of 1.8 to 3.0.
別の実用的な組成を例示すると、例えばＢ2元素としてＭnとＺnを複合添加した組成式ＢaＦe(12-x)(Ｔi0.5(Ｍn(1-y)Ｚny)0.5)xＯ19で表されるものが挙げられる。検討の結果、少なくともＭnとＺnのモル比が１：１付近（上記ｙが０.５±０.１）において、厚さによる整合周波数の変化が顕著に減少する効果が得られる。この場合、ｘは例えば３.６〜４.８の範囲とすることができる。 Another practical composition is exemplified by the composition formula BaFe (12-x) (Ti 0.5 (Mn (1-y) Zn y ) 0.5 ) x O 19 in which Mn and Zn are added as B2 elements. Can be mentioned. As a result of the study, at least when the molar ratio of Mn to Zn is around 1: 1 (the above y is 0.5 ± 0.1), the effect of significantly reducing the change in the matching frequency due to the thickness is obtained. In this case, x can be in the range of 3.6 to 4.8, for example.
本発明のマグネトプランバイト型六方晶フェライトは、一般的なソフトフェライトの製造方法に準じて製造することができる。例えば、原料として酸化物や炭酸塩の粉体を用い、これらを所定のフェライト組成となるように秤量し、混合、造粒したのち、焼成することにより所定組成のマグネトプランバイト型六方晶フェライトが得られる。これを粉砕して粉末とすればよい。 The magnetoplumbite type hexagonal ferrite of the present invention can be manufactured according to a general soft ferrite manufacturing method. For example, oxide or carbonate powder is used as a raw material, and these are weighed so as to have a predetermined ferrite composition, mixed, granulated, and then fired to obtain magnetoplumbite type hexagonal ferrite of a predetermined composition. can get. This may be pulverized into powder.
得られたマグネトプランバイト型六方晶フェライトの粉末は、高分子基材とともに混練することにより電波吸収体素材（混練物）が得られる。混練物中におけるマグネトプランバイト型六方晶フェライト粉末の配合量は６０質量％以上とすることが好ましい。ただし９５質量％を超えると高分子基材との混練が難しくなる。マグネトプランバイト型六方晶フェライト粉末の混合割合は８０〜９５質量％とすることがより好ましく、８５〜９５質量％が一層好ましい。 The obtained magnetoplumbite type hexagonal ferrite powder is kneaded with a polymer base material to obtain a radio wave absorber material (kneaded product). The blending amount of magnetoplumbite type hexagonal ferrite powder in the kneaded product is preferably 60% by mass or more. However, if it exceeds 95% by mass, kneading with the polymer substrate becomes difficult. The mixing ratio of the magnetoplumbite type hexagonal ferrite powder is more preferably 80 to 95% by mass, and still more preferably 85 to 95% by mass.
高分子基材としては、使用環境に応じて、耐熱性、難燃性、耐久性、機械的強度、電気的特性を満足する各種のものが使用できる。例えば、樹脂（ナイロン等）、ゲル（シリコーンゲル等）、熱可塑性エラストマー、ゴムなどから適切なものを選択すれば良い。また２種以上の高分子化合物をブレンドして基材としてもよい。 As the polymer substrate, various materials satisfying heat resistance, flame retardancy, durability, mechanical strength, and electrical characteristics can be used depending on the use environment. For example, an appropriate material may be selected from resin (nylon or the like), gel (silicone gel or the like), thermoplastic elastomer, rubber or the like. Two or more polymer compounds may be blended to form a base material.
高分子基材との相溶性や分散性を改善するために、マグネトプランバイト型六方晶フェライト粉末には予めシランカップリング剤、チタネートカップリング剤等による表面処理を施すことができる。また、マグネトプランバイト型六方晶フェライト粉末と高分子化合物との混合に際し、可塑剤、補強剤、耐熱向上剤、熱伝導性充填剤、粘着剤などの各種添加剤を添加することができる。 In order to improve the compatibility and dispersibility with the polymer substrate, the magnetoplumbite type hexagonal ferrite powder can be subjected to surface treatment with a silane coupling agent, a titanate coupling agent or the like in advance. In addition, when the magnetoplumbite type hexagonal ferrite powder and the polymer compound are mixed, various additives such as a plasticizer, a reinforcing agent, a heat resistance improver, a heat conductive filler, and an adhesive can be added.
上記電波吸収体素材（混練物）を圧延により所定のシート厚に成形することで電波吸収体が得られる。また、本発明のマグネトプランバイト型六方晶フェライトを用いると電波吸収体の厚さ寸法精度の許容量が緩和されるので、圧延の代わりに射出成形を施すこともできる。マグネトプランバイト型六方晶フェライト粉末を直接塗料中に分散させて、基体表面に塗布することにより、塗膜としての電波吸収体を形成することもできる。 A radio wave absorber can be obtained by forming the above radio wave absorber material (kneaded material) into a predetermined sheet thickness by rolling. Further, when the magnetoplumbite type hexagonal ferrite of the present invention is used, the allowable amount of thickness dimensional accuracy of the radio wave absorber is relaxed, and therefore, injection molding can be performed instead of rolling. The electromagnetic wave absorber as a coating film can also be formed by dispersing the magnetoplumbite type hexagonal ferrite powder directly in the paint and applying it to the surface of the substrate.
〔実施例１〕
原料粉として、α−Ｆe2Ｏ3、ＢaＣＯ3、ＴiＯ2、Ｃo3Ｏ4およびＺnＯを用い、これらを下記組成に対応する量比で秤量した。
組成：ＢaＦe(12-x)(Ｔi0.5(Ｃo0.5Ｚn0.5)0.5)xＯ19、ｘ＝２.４
秤量後の原料粉をハイスピードミキサーで混合し、更に振動ミルにより乾式法で混合強化した。得られた混合粉をペレット状に造粒成形し、この成形体をローラーハース型電気炉に装入し、大気中１２５０℃で２時間保持することにより焼成した。得られた焼成品をハンマーミルで粗粉砕して粒径１ｍｍ以下とした後、更にボールミルを用いて乾式法で微粉砕して平均粒径１０μｍ以下とした。
Ｘ線回折の結果、この微粉砕品はマグネトプランバイト型六方晶フェライトであることが確認された。
[Example 1]
Α-Fe 2 O 3 , BaCO 3 , TiO 2 , Co 3 O 4 and ZnO were used as raw material powders, and these were weighed at a quantitative ratio corresponding to the following composition.
Composition: BaFe (12-x) (Ti 0.5 (Co 0.5 Zn 0.5 ) 0.5 ) x O 19 , x = 2.4
The raw material powder after weighing was mixed with a high speed mixer, and further mixed and strengthened by a dry method using a vibration mill. The obtained mixed powder was granulated and formed into pellets, and the formed body was placed in a roller hearth type electric furnace and fired by holding at 1250 ° C. in the atmosphere for 2 hours. The obtained fired product was coarsely pulverized with a hammer mill to a particle size of 1 mm or less, and further pulverized by a dry method using a ball mill to an average particle size of 10 μm or less.
As a result of X-ray diffraction, it was confirmed that the finely pulverized product was a magnetoplumbite type hexagonal ferrite.
上記微粉砕品の含有量が８５質量％となるように、当該粉末と合成ゴム（ＪＳＲ（日本合成ゴム）製、Ｎ２１５ＳＬ）を混練して電波吸収体素材（混練物）を作製した。この電波吸収体素材を圧延ロールにより厚さ２ｍｍに圧延し、電波吸収体シートを得た。このシートを後述の電波吸収特性の測定に供した。 The powder and synthetic rubber (JSR (Nippon Synthetic Rubber), N215SL) were kneaded so that the content of the finely pulverized product was 85% by mass to prepare a radio wave absorber material (kneaded material). The radio wave absorber material was rolled to a thickness of 2 mm with a rolling roll to obtain a radio wave absorber sheet. This sheet was subjected to the measurement of the radio wave absorption characteristics described later.
〔実施例２〕
実施例１と同じ原料粉を用い、これらを下記組成に対応する量比で秤量した。
組成：ＢaＦe(12-x)(Ｔi0.5(Ｃo0.67Ｚn0.33)0.5)xＯ19、ｘ＝２.２
その後、実施例１と同様のプロセスを経て平均粒径１０μｍ以下の微粉砕粉末を得た。Ｘ線回折の結果、この微粉砕品はマグネトプランバイト型六方晶フェライトであることが確認された。この微粉砕品を用いて実施例１と同様の方法で厚さ２ｍｍのシートとし、後述の電波吸収特性の測定に供した。
[Example 2]
The same raw material powder as in Example 1 was used and weighed at a quantitative ratio corresponding to the following composition.
Composition: BaFe (12-x) (Ti 0.5 (Co 0.67 Zn 0.33 ) 0.5 ) x O 19 , x = 2.2
Thereafter, a finely pulverized powder having an average particle size of 10 μm or less was obtained through the same process as in Example 1. As a result of X-ray diffraction, it was confirmed that the finely pulverized product was a magnetoplumbite type hexagonal ferrite. Using this finely pulverized product, a sheet having a thickness of 2 mm was prepared in the same manner as in Example 1 and subjected to measurement of radio wave absorption characteristics described later.
〔実施例３〕
実施例１と同じ原料粉を用い、これらを下記組成に対応する量比で秤量した。
組成：ＢaＦe(12-x)(Ｔi0.5(Ｃo0.25Ｚn0.75)0.5)xＯ19、ｘ＝２.４
その後、実施例１と同様のプロセスを経て平均粒径１０μｍ以下の微粉砕粉末を得た。Ｘ線回折の結果、この微粉砕品はマグネトプランバイト型六方晶フェライトであることが確認された。この微粉砕品を用いて実施例１と同様の方法で厚さ２ｍｍのシートとし、後述の電波吸収特性の測定に供した。
Example 3
The same raw material powder as in Example 1 was used and weighed at a quantitative ratio corresponding to the following composition.
Composition: BaFe (12-x) (Ti 0.5 (Co 0.25 Zn 0.75 ) 0.5 ) x O 19 , x = 2.4
Thereafter, a finely pulverized powder having an average particle size of 10 μm or less was obtained through the same process as in Example 1. As a result of X-ray diffraction, it was confirmed that the finely pulverized product was a magnetoplumbite type hexagonal ferrite. Using this finely pulverized product, a sheet having a thickness of 2 mm was prepared in the same manner as in Example 1 and subjected to measurement of radio wave absorption characteristics described later.
〔比較例１〕
原料粉として、α−Ｆe2Ｏ3、ＢaＣＯ3、ＴiＯ2およびＣo3Ｏ4を用い、これらを下記組成に対応する量比で秤量した。
組成：ＢaＦe(12-x)(Ｔi0.5Ｃo0.5)xＯ19、ｘ＝１.８
その後、実施例１と同様のプロセスを経て平均粒径１０μｍ以下の微粉砕粉末を得た。Ｘ線回折の結果、この微粉砕品はマグネトプランバイト型六方晶フェライトであることが確認された。この微粉砕品を用いて実施例１と同様の方法で厚さ２ｍｍのシートとし、後述の電波吸収特性の測定に供した。
[Comparative Example 1]
As raw material powder, α-Fe 2 O 3 , BaCO 3 , TiO 2 and Co 3 O 4 were used and weighed at a quantitative ratio corresponding to the following composition.
Composition: BaFe (12-x) (Ti 0.5 Co 0.5 ) x O 19 , x = 1.8
Thereafter, a finely pulverized powder having an average particle size of 10 μm or less was obtained through the same process as in Example 1. As a result of X-ray diffraction, it was confirmed that the finely pulverized product was a magnetoplumbite type hexagonal ferrite. Using this finely pulverized product, a sheet having a thickness of 2 mm was prepared in the same manner as in Example 1 and subjected to measurement of radio wave absorption characteristics described later.
〔比較例２〕
原料粉として、α−Ｆe2Ｏ3、ＢaＣＯ3、ＴiＯ2およびＺnＯを用い、これらを下記組成に対応する量比で秤量した。
組成：ＢaＦe(12-x)(Ｔi0.5Ｚn0.5)xＯ19、ｘ＝２.４
その後、実施例１と同様のプロセスを経て平均粒径１０μｍ以下の微粉砕粉末を得た。Ｘ線回折の結果、この微粉砕品はマグネトプランバイト型六方晶フェライトであることが確認された。この微粉砕品を用いて実施例１と同様の方法で厚さ２ｍｍのシートとし、後述の電波吸収特性の測定に供した。
しかし、この組成のものは目的範囲で電波吸収性能を発現しなかった。
[Comparative Example 2]
Α-Fe 2 O 3 , BaCO 3 , TiO 2 and ZnO were used as raw material powders, and these were weighed at a quantitative ratio corresponding to the following composition.
Composition: BaFe (12-x) (Ti 0.5 Zn 0.5 ) x O 19 , x = 2.4
Thereafter, a finely pulverized powder having an average particle size of 10 μm or less was obtained through the same process as in Example 1. As a result of X-ray diffraction, it was confirmed that the finely pulverized product was a magnetoplumbite type hexagonal ferrite. Using this finely pulverized product, a sheet having a thickness of 2 mm was prepared in the same manner as in Example 1 and subjected to measurement of radio wave absorption characteristics described later.
However, this composition did not exhibit radio wave absorption performance in the target range.
〔実施例４〕
原料粉として、α−Ｆe2Ｏ3、ＢaＣＯ3、ＴiＯ2、ＭnＯ2およびＺnＯを用い、これらを下記組成に対応する量比で秤量した。
組成：ＢaＦe(12-x)(Ｔi0.5(Ｍn0.5Ｚn0.5)0.5)xＯ19、ｘ＝４.０
その後、実施例１と同様のプロセスを経て平均粒径１０μｍ以下の微粉砕粉末を得た。Ｘ線回折の結果、この微粉砕品はマグネトプランバイト型六方晶フェライトであることが確認された。この微粉砕品を用いて実施例１と同様の方法で厚さ２ｍｍのシートとし、後述の電波吸収特性の測定に供した。
Example 4
Α-Fe 2 O 3 , BaCO 3 , TiO 2 , MnO 2 and ZnO were used as raw material powders, and these were weighed at a quantitative ratio corresponding to the following composition.
Composition: BaFe (12-x) (Ti 0.5 (Mn 0.5 Zn 0.5 ) 0.5 ) x O 19 , x = 4.0
Thereafter, a finely pulverized powder having an average particle size of 10 μm or less was obtained through the same process as in Example 1. As a result of X-ray diffraction, it was confirmed that the finely pulverized product was a magnetoplumbite type hexagonal ferrite. Using this finely pulverized product, a sheet having a thickness of 2 mm was prepared in the same manner as in Example 1 and subjected to measurement of radio wave absorption characteristics described later.
〔比較例３〕
原料粉として、α−Ｆe2Ｏ3、ＢaＣＯ3、ＴiＯ2およびＭnＯ2を用い、これらを下記組成に対応する量比で秤量した。
組成：ＢaＦe(12-x)(Ｔi0.5Ｍn0.5)xＯ19、ｘ＝４.０
その後、実施例１と同様のプロセスを経て平均粒径１０μｍ以下の微粉砕粉末を得た。ただし、焼成温度は１２５０℃とした。Ｘ線回折の結果、この微粉砕品はマグネトプランバイト型六方晶フェライトであることが確認された。この微粉砕品を用いて実施例１と同様の方法で厚さ２ｍｍのシートとし、後述の電波吸収特性の測定に供した。
[Comparative Example 3]
Α-Fe 2 O 3 , BaCO 3 , TiO 2 and MnO 2 were used as raw material powders, and these were weighed at a quantitative ratio corresponding to the following composition.
Composition: BaFe (12-x) (Ti 0.5 Mn 0.5 ) x O 19 , x = 4.0
Thereafter, a finely pulverized powder having an average particle size of 10 μm or less was obtained through the same process as in Example 1. However, the firing temperature was 1250 ° C. As a result of X-ray diffraction, it was confirmed that the finely pulverized product was a magnetoplumbite type hexagonal ferrite. Using this finely pulverized product, a sheet having a thickness of 2 mm was prepared in the same manner as in Example 1 and subjected to measurement of radio wave absorption characteristics described later.
〔電波吸収特性の評価〕
得られた電波吸収体シートについてＳパラメーター法により電波吸収特性を調べた。シートから切り出した小片を外径７ｍｍ、内径３ｍｍの円筒状測定ピースに成形し、これをφ７ｍｍ×φ３.０４ｍｍの同軸管に挿入し、同軸管の端をショートホルダーで短絡し、ネットワークアナライザー（ヒュレットパッカード社製、ＨＰ８７２０Ｄ）を用いて１〜２０ＧＨｚにおける反射量（Ｓ１１）を測定した。試料を挿入した場合の反射量から、試料を挿入しない場合の反射量を引いた値を吸収量（反射減衰量）と定義し、これにより電波吸収特性を評価した。測定されたＳパラメーターから、１〜４ｍｍの種々の厚さのシートにおける電波吸収特性をシミュレートした。
[Evaluation of radio wave absorption characteristics]
The obtained radio wave absorber sheet was examined for radio wave absorption characteristics by the S parameter method. A small piece cut out from the sheet is formed into a cylindrical measuring piece having an outer diameter of 7 mm and an inner diameter of 3 mm, which is inserted into a φ7 mm × φ3.04 mm coaxial tube, and the end of the coaxial tube is short-circuited with a short holder. The amount of reflection (S11) at 1 to 20 GHz was measured using a HP 8720D manufactured by Ret Packard. A value obtained by subtracting the reflection amount when the sample was not inserted from the reflection amount when the sample was inserted was defined as an absorption amount (reflection attenuation amount), and thereby the radio wave absorption characteristics were evaluated. From the measured S-parameters, radio wave absorption characteristics of sheets having various thicknesses of 1 to 4 mm were simulated.
このシミュレート結果を基に、目標周波数付近におけるシート厚さと整合周波数の関係調べ、電波吸収体の厚さ変動による整合周波数の変化の程度を評価した。その評価手法を以下に説明する。 Based on the simulation results, the relationship between the sheet thickness near the target frequency and the matching frequency was investigated, and the degree of change in the matching frequency due to the thickness variation of the wave absorber was evaluated. The evaluation method will be described below.
図１に、実施例１および比較例１の各シート厚さにおける周波数と吸収量の関係（シミュレート結果）を例示する。これらの例は概ね１２ＧＨｚ前後の周波数を目標としたものである。図１に示される各シート厚さの曲線のうち、約−１５ｄＢ以下の吸収量が得られるシート厚さの曲線を選択し、その頂点（図１における下向きの頂点）の周波数と吸収量を読み取る。各頂点のプロットを結ぶと図２のようになる。図２のプロットを、頂点の周波数とシート厚さの関係に直してプロットすると、図３（実施例１）および図４（比較例１）のように、整合周波数とシート厚さの関係は概ね直線状の関係になる。そこで最小二乗法により各プロットの並びを直線で近似する。図３、図４中、「線形」と記載したものがこの近似直線である。この近似直線の傾きの絶対値が大きいほど、電波吸収体厚さの変動に対する整合周波数の変化量が小さくなり、所定の周波数領域に適用可能な厚さの許容範囲が拡大することになる。 FIG. 1 illustrates the relationship between the frequency and the amount of absorption (simulation results) in each sheet thickness of Example 1 and Comparative Example 1. These examples are targeted for frequencies around 12 GHz. From the sheet thickness curves shown in FIG. 1, a sheet thickness curve that provides an absorption amount of about −15 dB or less is selected, and the frequency and absorption amount at the apex (downward apex in FIG. 1) are read. . The plots of the vertices are connected as shown in FIG. When the plot of FIG. 2 is plotted by revising the relationship between the peak frequency and the sheet thickness, the relationship between the matching frequency and the sheet thickness is almost as shown in FIG. 3 (Example 1) and FIG. 4 (Comparative Example 1). It becomes a linear relationship. Therefore, the arrangement of each plot is approximated by a straight line by the least square method. In FIG. 3 and FIG. 4, what is described as “linear” is this approximate straight line. As the absolute value of the slope of the approximate line increases, the amount of change in the matching frequency with respect to fluctuations in the thickness of the radio wave absorber is reduced, and the allowable range of thickness applicable to a predetermined frequency region is expanded.
他の実施例、比較例についても上記と同様の手法により、電波吸収体の厚さ変動による整合周波数の変化の程度を評価した。各実施例、比較例についての整合周波数とシート厚さの関係を図３〜図８に示した。ただし、比較例２では電波吸収特性が確認できなかったため評価不能であった。 For other examples and comparative examples, the degree of change in the matching frequency due to the thickness variation of the radio wave absorber was evaluated by the same method as described above. The relationship between the matching frequency and the sheet thickness for each example and comparative example is shown in FIGS. However, in Comparative Example 2, since the radio wave absorption characteristics could not be confirmed, the evaluation was impossible.
図３（実施例１）、図４（比較例１）、図５（実施例２）、図６（実施例３）から判るように、比較例１のグラフの傾きの絶対値は０.１２０２であるのに対し、実施例１、実施例２および実施例３のグラフの傾きの絶対値はそれぞれ０.８４５２、０.４２６８および０.７７２６と大きかった。すなわち、２価の金属元素としてＣoとＺnを複合添加した実施例１〜３のマグネトプランバイト型六方晶フェライトは、Ｃo単独添加の比較例１ものと比べ、電波吸収体の厚さ変動による整合周波数の変化の程度が顕著に小さくなっていることがわかる。 As can be seen from FIG. 3 (Example 1), FIG. 4 (Comparative Example 1), FIG. 5 (Example 2), and FIG. 6 (Example 3), the absolute value of the slope of the graph of Comparative Example 1 is 0.1022. On the other hand, the absolute values of the slopes of the graphs of Example 1, Example 2 and Example 3 were as large as 0.8852, 0.4268 and 0.7726, respectively. That is, the magnetoplumbite type hexagonal ferrites of Examples 1 to 3 in which Co and Zn are added together as a divalent metal element are matched by the variation in the thickness of the radio wave absorber as compared with Comparative Example 1 in which only Co is added. It can be seen that the degree of frequency change is significantly reduced.
また、図７（実施例５）、図８（比較例３）は概ね１５ＧＨｚ前後の周波数を目標としたものであるが、これらの図から判るように、比較例３のグラフの傾きの絶対値は０.０９１０であるのに対し、実施例５では０.３７４９と大きかった。すなわち、２価の金属元素としてＭnとＺnを複合添加した実施例５のマグネトプランバイト型六方晶フェライトは、Ｍn単独添加の比較例３ものと比べ、電波吸収体の厚さ変動による整合周波数の変化の程度が顕著に小さくなっていることがわかる。 Further, FIG. 7 (Example 5) and FIG. 8 (Comparative Example 3) are aimed at a frequency of approximately 15 GHz. As can be seen from these figures, the absolute value of the slope of the graph of Comparative Example 3 is shown. Was 0.0910, whereas in Example 5, it was as large as 0.3749. That is, the magnetoplumbite type hexagonal ferrite of Example 5 in which Mn and Zn are added together as a divalent metal element has a matching frequency due to the fluctuation of the thickness of the radio wave absorber as compared with Comparative Example 3 in which Mn alone is added. It can be seen that the degree of change is significantly reduced.
図９は、実施例１〜３および比較例１、２について、Ｚn／(Ｃo＋Ｚn)のモル比を表すｙの値と、近似直線の傾きの絶対値の関係をプロットしたものである。ｙ＝１（比較例２）では目標の周波数領域（１２ＧＨｚ付近）で電波吸収特性を示さなかったため、傾き＝０（最も悪い評価）として表示してある。図９から、２価の金属元素を複合添加することにより「電波吸収体の厚さ変動による整合周波数の変化の程度が小さくなる効果」が得られることが判る。 FIG. 9 is a plot of the relationship between the value of y representing the molar ratio of Zn / (Co + Zn) and the absolute value of the slope of the approximate line for Examples 1 to 3 and Comparative Examples 1 and 2. Since y = 1 (Comparative Example 2) did not show radio wave absorption characteristics in the target frequency region (near 12 GHz), it is displayed as slope = 0 (worst evaluation). From FIG. 9, it can be seen that the “effect of reducing the degree of change in the matching frequency due to the thickness variation of the radio wave absorber” can be obtained by adding the divalent metal element in combination.
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008169378A (en) * | 2006-12-12 | 2008-07-24 | Asahi Kasei Chemicals Corp | Resin composition |
| US8263224B2 (en) | 2006-11-29 | 2012-09-11 | Asahi Kasei Chemicals Corporation | Resin composition |
| JP2013115089A (en) * | 2011-11-25 | 2013-06-10 | Tdk Corp | Magnetic oxide sintered compact, and antenna and radio communication device, both using the same |
| JP2014192344A (en) * | 2013-03-27 | 2014-10-06 | Tdk Corp | Magnetic oxide sintered body and high-frequency magnetic component using the same |
| JP2016086112A (en) * | 2014-10-28 | 2016-05-19 | Tdk株式会社 | Hexagonal ferrite composite magnetic material, and high-frequency magnetic part arranged by use thereof |
| CN109574083A (en) * | 2018-12-04 | 2019-04-05 | 浙江安特磁材有限公司 | A kind of rubber ferromagnetic oxide powder and preparation method thereof, magnetic product and application |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11354972A (en) * | 1998-06-10 | 1999-12-24 | Tdk Corp | Radio wave absorber |
| JP2003146739A (en) * | 2001-08-27 | 2003-05-21 | Murata Mfg Co Ltd | Magnetic material for high frequency and high frequency circuit element using the same |
-
2004
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11354972A (en) * | 1998-06-10 | 1999-12-24 | Tdk Corp | Radio wave absorber |
| JP2003146739A (en) * | 2001-08-27 | 2003-05-21 | Murata Mfg Co Ltd | Magnetic material for high frequency and high frequency circuit element using the same |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8263224B2 (en) | 2006-11-29 | 2012-09-11 | Asahi Kasei Chemicals Corporation | Resin composition |
| JP2008169378A (en) * | 2006-12-12 | 2008-07-24 | Asahi Kasei Chemicals Corp | Resin composition |
| JP2013115089A (en) * | 2011-11-25 | 2013-06-10 | Tdk Corp | Magnetic oxide sintered compact, and antenna and radio communication device, both using the same |
| JP2014192344A (en) * | 2013-03-27 | 2014-10-06 | Tdk Corp | Magnetic oxide sintered body and high-frequency magnetic component using the same |
| JP2016086112A (en) * | 2014-10-28 | 2016-05-19 | Tdk株式会社 | Hexagonal ferrite composite magnetic material, and high-frequency magnetic part arranged by use thereof |
| CN109574083A (en) * | 2018-12-04 | 2019-04-05 | 浙江安特磁材有限公司 | A kind of rubber ferromagnetic oxide powder and preparation method thereof, magnetic product and application |
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