JP2000200990A - High corrosion resistant microwave absorber - Google Patents
High corrosion resistant microwave absorberInfo
- Publication number
- JP2000200990A JP2000200990A JP11002297A JP229799A JP2000200990A JP 2000200990 A JP2000200990 A JP 2000200990A JP 11002297 A JP11002297 A JP 11002297A JP 229799 A JP229799 A JP 229799A JP 2000200990 A JP2000200990 A JP 2000200990A
- Authority
- JP
- Japan
- Prior art keywords
- electromagnetic wave
- rubber
- soft magnetic
- resin
- powder
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- 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
- H01F1/14—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 metals or alloys
- H01F1/20—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 metals or alloys in the form of particles, e.g. powder
- H01F1/22—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 metals or alloys in the form of particles, e.g. powder pressed, sintered, or bound together
- H01F1/24—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 metals or alloys in the form of particles, e.g. powder pressed, sintered, or bound together the particles being insulated
- H01F1/26—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 metals or alloys in the form of particles, e.g. powder pressed, sintered, or bound together the particles being insulated by macromolecular organic substances
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は高耐食性電磁波吸収
体に関する。The present invention relates to a high corrosion resistant electromagnetic wave absorber.
【０００２】[0002]
【従来の技術】近年、パソコンや携帯電話等の電子機器
の小型化・高性能化の進展に伴い、これらの機器に用い
られる回路（ＩＣやＬＳＩ）やＣＰＵも高周波化されて
きており、これらの素子から発生するＧＨｚ帯での電磁
波ノイズについての対策が必要となってきている。例え
ば、病院等の医療現場においては、上述の高周波ノイズ
が医療用の電子機器の誤作動を招くおそれがあるため、
ＧＨｚ帯での電磁波を遮蔽することのできる材料が要望
されている。2. Description of the Related Art In recent years, with the advance of miniaturization and high performance of electronic devices such as personal computers and mobile phones, circuits (ICs and LSIs) and CPUs used in these devices have been used at higher frequencies. It is becoming necessary to take measures against the electromagnetic wave noise in the GHz band generated from the element. For example, in a medical site such as a hospital, the above-described high-frequency noise may cause malfunction of a medical electronic device,
There is a need for a material that can shield electromagnetic waves in the GHz band.
【０００３】ところで、上述のＧＨｚ帯での電磁波ノイ
ズは、その波長が電子機器の大きさと同程度（数ｃｍ）
になっており、この電磁波が機器の内部で輻射や干渉を
生じる恐れがある。そのため、電磁波を吸収する材料の
開発が必要になってくる。このような電磁波吸収体とし
て、軟磁性材料の粉末をゴムや樹脂に分散させた電磁波
吸収用シートが提案されている（特開平１０−５６２９
２号、同２６１５１６号参照）。この電磁波吸収用シー
トは、以下のようにして電磁波を吸収するものである。
まず、低周波の電磁波ノイズが加わった場合には、軟磁
性粉末が持つ微小磁石が外部磁界の方向に向きを変える
ので、外部磁界の抵抗とはならず、電磁波を吸収しな
い。ところが、ノイズ周波数が増大すると、微小磁石の
方向を変えるのが磁界の時間的変動に対して遅れ、磁石
が外部磁界の抵抗となって電磁波を吸収するようにな
る。一方、外部磁界の周波数がさらに増大した場合に
は、微小磁石は外部磁界に対して静止しているのと同等
となるため、外部磁界に抵抗することはできず、電磁波
を吸収することができなくなる。すなわち、この電磁波
吸収用シートは、特定の周波数の電磁波を吸収するとい
う特性を有している。Meanwhile, the electromagnetic wave noise in the above-mentioned GHz band has a wavelength approximately equal to the size of electronic equipment (several cm).
This electromagnetic wave may cause radiation or interference inside the device. Therefore, it is necessary to develop a material that absorbs electromagnetic waves. As such an electromagnetic wave absorber, an electromagnetic wave absorbing sheet in which powder of a soft magnetic material is dispersed in rubber or resin has been proposed (JP-A-10-5629).
Nos. 2, 261516). This sheet for absorbing electromagnetic waves absorbs electromagnetic waves as follows.
First, when low frequency electromagnetic wave noise is added, the small magnet of the soft magnetic powder changes its direction in the direction of the external magnetic field, so that it does not become the resistance of the external magnetic field and does not absorb the electromagnetic wave. However, when the noise frequency increases, changing the direction of the minute magnet is delayed with respect to the temporal fluctuation of the magnetic field, and the magnet becomes a resistance of the external magnetic field and absorbs the electromagnetic wave. On the other hand, if the frequency of the external magnetic field further increases, the micromagnet is equivalent to being stationary with respect to the external magnetic field, and therefore cannot resist the external magnetic field and can absorb electromagnetic waves. Disappears. That is, the electromagnetic wave absorbing sheet has a characteristic of absorbing an electromagnetic wave of a specific frequency.
【０００４】これらの技術においては、ＧＨｚ帯の電磁
波を有効に吸収するために、高周波での電磁波吸収能に
優れる金属（Ｆｅ、Ｎｉ，Ｃｏ等）やこれらの合金、あ
るいはＦｅ−Ｃｒ系合金を所定の大きさに粉状化したも
のを用いている。そして、高周波における粉末の透磁率
の低下を防止するため適宜、粉末を偏平化している。ま
た、これらのシートはその基体として軟質なゴムやプラ
スチックを用いているため絶縁性に優れ、従来のパーマ
ロイ等の電磁波遮蔽板に比べて、電子機器や素子に直接
貼り付けが可能となる。また、個々の電子機器等をより
完全に被覆できるので、電磁波を効果的に吸収できると
いう利点がある。[0004] In these techniques, in order to effectively absorb electromagnetic waves in the GHz band, metals (Fe, Ni, Co, etc.) excellent in electromagnetic wave absorption at high frequencies, alloys thereof, or Fe-Cr alloys are used. A powdered one having a predetermined size is used. The powder is appropriately flattened in order to prevent a decrease in the magnetic permeability of the powder at a high frequency. Further, since these sheets use soft rubber or plastic as their base, they have excellent insulation properties, and can be directly attached to electronic devices and elements as compared with conventional electromagnetic wave shielding plates such as permalloy. Further, since individual electronic devices and the like can be more completely covered, there is an advantage that electromagnetic waves can be effectively absorbed.
【０００５】[0005]
【発明が解決しようとする課題】しかしながら、上記し
た電磁波吸収用シートの場合、金属や合金の粉末を用い
るためにシートの耐食性が良好ではなく、金属粉末が腐
食して電磁波吸収能が低下する可能性がある。特に、医
療用の機器にこのシートを用いる場合、病院内における
生理食塩水等を含む腐食雰囲気に、シートが曝される可
能性が高くなる。また、携帯電話や屋外に取付ける電子
機器等にこのシートを用いる場合も、屋外の腐食環境に
曝されることが多いと考えられる。However, in the case of the above-mentioned electromagnetic wave absorbing sheet, since the metal or alloy powder is used, the corrosion resistance of the sheet is not good, and the metal powder is corroded and the electromagnetic wave absorbing ability may be reduced. There is. In particular, when this sheet is used for medical equipment, the possibility that the sheet is exposed to a corrosive atmosphere containing a physiological saline solution or the like in a hospital increases. Also, when this sheet is used for a mobile phone or an electronic device to be installed outdoors, it is considered that the sheet is often exposed to an outdoor corrosive environment.
【０００６】特に、Ｆｅ系の金属粉末を用いた場合、粉
末のコストが低いためにシート自体も極めて安価となる
が、シートの耐食性に劣るという欠点があり、製品寿命
が短くなるため、結局コスト上昇を招くことにもなって
いる。そこで、耐食性に優れるＦｅ系合金として、ステ
ンレス鋼等のＦｅ−Ｃｒ合金を用いることも考えられる
が、Ｆｅ−Ｃｒ合金は隙間腐食を生じ易いという問題が
あり、これを粉末にしてゴムや樹脂に分散させた場合、
シートとしての耐食性がどのようになるかは不明であ
る。そして、従来品と同様の周波数の電磁波を吸収する
ことができ、さらにシートの耐食性及びコストの双方を
満足するようなＦｅ−Ｃｒ合金の合金組成については、
従来の技術において何ら開示されていない。[0006] In particular, when Fe-based metal powder is used, the sheet itself is extremely inexpensive due to the low cost of the powder. However, there is a disadvantage that the corrosion resistance of the sheet is poor, and the product life is shortened. It will also lead to a rise. Therefore, as an Fe-based alloy having excellent corrosion resistance, it is conceivable to use an Fe-Cr alloy such as stainless steel. However, the Fe-Cr alloy has a problem that crevice corrosion easily occurs. If dispersed,
It is unknown how the corrosion resistance of the sheet will be. And about the alloy composition of the Fe-Cr alloy which can absorb the electromagnetic wave of the same frequency as the conventional product, and further satisfies both the corrosion resistance and the cost of the sheet,
Nothing is disclosed in the prior art.
【０００７】本発明は、電磁波吸収体における上記した
問題を解決することができ、製品コストが低く、かつ耐
食性に優れた電磁波吸収体の提供を目的とする。An object of the present invention is to provide an electromagnetic wave absorber which can solve the above-mentioned problems in the electromagnetic wave absorber, has a low product cost, and is excellent in corrosion resistance.
【０００８】[0008]
【課題を解決するための手段】上記した目的を達成する
ために、請求項１記載の本発明においては、Ｃｒ：５〜
３５重量％を含むＦｅ基合金から成る軟磁性粉末がゴム
又は樹脂に分散して成ることを特徴とする高耐食性電磁
波吸収体が提供される。好ましくは、前記軟磁性粉末
は、Ｃｒ含有量が１０〜３５重量％のフェライト系ステ
ンレス鋼又はマルテンサイト系ステンレス鋼の粉末であ
るのがよい（請求項２）。In order to achieve the above object, in the present invention according to claim 1, Cr: 5 to 5 is used.
A highly corrosion-resistant electromagnetic wave absorber characterized in that soft magnetic powder composed of an Fe-based alloy containing 35% by weight is dispersed in rubber or resin. Preferably, the soft magnetic powder is a powder of ferritic stainless steel or martensitic stainless steel having a Cr content of 10 to 35% by weight (claim 2).
【０００９】また、前記軟磁性粉末が５〜６５体積％の
割合で含有されているのがよい（請求項３）。It is preferable that the soft magnetic powder is contained in a ratio of 5 to 65% by volume.
【００１０】[0010]
【発明の実施の形態】本発明は、ゴムや樹脂中に分散さ
れた状態においても隙間腐食等を生じることのない金属
粉末として、後述する成分組成を有するＦｅ−Ｃｒ合金
粉末を用い、電磁波吸収体としての耐食性の向上を図っ
たものである。以下、本発明の電磁波吸収体を、図１に
基づいて説明する。DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention uses an Fe-Cr alloy powder having a component composition described below as a metal powder that does not cause crevice corrosion or the like even when dispersed in rubber or resin, It is intended to improve the corrosion resistance of the body. Hereinafter, the electromagnetic wave absorber of the present invention will be described with reference to FIG.
【００１１】図１において、電磁波吸収体１は、軟磁性
粉末２がゴム（樹脂）４に分散されて構成されている。
この場合、後述するように粉末２が偏平化され、その長
径方向が電磁波Ｐの伝搬方向にほぼ直交するようにゴム
(樹脂)４中に分散されていると、電磁波吸収能が向上す
るので、比較的周波数の低い領域において好ましい。ま
た、金属粉末２同士が接触しないようにゴム(樹脂)４中
に一様に分散されていると、同様に電磁波吸収能が向上
し、絶縁性も向上するので好ましい。In FIG. 1, an electromagnetic wave absorber 1 is composed of a soft magnetic powder 2 dispersed in a rubber (resin) 4.
In this case, the powder 2 is flattened as described later, and the rubber 2 is set so that its major axis direction is substantially perpendicular to the propagation direction of the electromagnetic wave P.
When dispersed in the (resin) 4, the electromagnetic wave absorbing ability is improved, so that it is preferable in a relatively low frequency region. It is also preferable that the metal powders 2 are uniformly dispersed in the rubber (resin) 4 so as not to come into contact with each other, because the electromagnetic wave absorbing ability is similarly improved and the insulating property is also improved.
【００１２】軟磁性粉末は、Ｃｒ：５〜３５重量％を含
むＦｅ基合金の粉末から成っている。Ｃｒが５重量％未
満であるとシート等にした場合の耐食性が低下し、又、
３５重量％を超えると飽和磁束密度が低下するとともに
コストが上昇するからである。例えば、成分組成とし
て、Ｃｒ含有量：５〜３５重量％、Ｓｉ含有量：０．０
０１〜１．５未満重量％、Ａｌ含有量：０．０１〜２０
重量％、残部Ｆｅ及び不可避不純物となっているものを
あげることができる。ここで、Ｓｉは電気抵抗を高くす
る元素であり、０．００１％重量未満であるとその効果
が発揮されず、０．５重量％以上であると後述する偏平
化を阻害するため上記の範囲とするのがよい。Ａｌは偏
平加工性、電気抵抗、及び耐食性をともに高くする元素
であり、０．０１重量％未満であるとその効果が発揮さ
れず、２０重量％を超えると偏平化を阻害するため上記
の範囲とするのがよい。さらに好ましくは、Ｃｒ含有
量：５〜２０重量％、Ｓｉ含有量：０．０５〜１．０重
量％、Ａｌ含有量：４〜１５重量％であるとよい。The soft magnetic powder is composed of an Fe-based alloy powder containing 5 to 35% by weight of Cr. If the Cr content is less than 5% by weight, the corrosion resistance of a sheet or the like is reduced, and
If the content exceeds 35% by weight, the saturation magnetic flux density decreases and the cost increases. For example, as the component composition, Cr content: 5-35% by weight, Si content: 0.0
01 to less than 1.5% by weight, Al content: 0.01 to 20
% By weight, the balance being Fe and unavoidable impurities. Here, Si is an element that increases the electric resistance. If the content is less than 0.001% by weight, the effect is not exhibited. If the content is 0.5% by weight or more, flattening described later is inhibited, so that Si is in the above range. It is good to do. Al is an element that increases both flat workability, electrical resistance, and corrosion resistance. If the content is less than 0.01% by weight, the effect is not exhibited. If the content exceeds 20% by weight, flattening is hindered. It is good to do. More preferably, the Cr content is 5 to 20% by weight, the Si content is 0.05 to 1.0% by weight, and the Al content is 4 to 15% by weight.
【００１３】また、不可避不純物としては、例えばＣ、
Ｍｎ、Ｃｕ、Ｎｉ、Ｐ、Ｓなどをあげることができる
が、これらは以下の量に規制されているのが好ましい。
Ｃは飽和磁束密度を低下させる元素であるため、０．１
５重量％以下とするのがよい。Ｍｎも同様な理由から、
０．３重量％以下とするのがよい。Ｃｕ、Ｎｉ、及びＭ
ｏも、同様に０．６重量％以下とするのがよい。Ｐ及び
Ｓは偏平加工性や耐食性を低下させるため、０．０４重
量％以下とするのがよい。The inevitable impurities include, for example, C,
Mn, Cu, Ni, P, S and the like can be mentioned, and these are preferably regulated to the following amounts.
C is an element that lowers the saturation magnetic flux density.
The content is preferably 5% by weight or less. For the same reason, Mn also
The content is preferably not more than 0.3% by weight. Cu, Ni, and M
Similarly, o is preferably set to 0.6% by weight or less. P and S are preferably set to 0.04% by weight or less in order to reduce flat workability and corrosion resistance.
【００１４】特に、Ｃｒ含有量が１０〜３５重量％のフ
ェライト系又はマルテンサイト系ステンレス鋼の粉末で
あるのが好ましい。このようなステンレス鋼としては、
ＪＩＳに規格するＳＵＳ４１０鋼、ＳＵＳ４１０Ｌ鋼、
ＳＵＳ４３０鋼、及びＳＵＳ４３０Ｌ鋼を例示すること
ができる。粉末の大きさは、例えば、平均粒径１００μ
ｍ以下とすることが好ましい。なお、平均粒径とは、全
粒子重量に対する累積重量が５０％となる粒子径をいう
（通常Ｄ５０と称される）。また、粒子形状は特に限定
されないが、所望の電磁波吸収特性を得るため適宜、粉
末の偏平化を行う。例えば、アスペクト比が１０以上、
さらに好ましくは２５以上とすることにより、１０ＧＨ
ｚ以下の周波数で良好な吸収能が得られる。In particular, it is preferable to use a powder of ferritic or martensitic stainless steel having a Cr content of 10 to 35% by weight. As such stainless steel,
JIS SUS410 steel, SUS410L steel,
SUS430 steel and SUS430L steel can be exemplified. The size of the powder is, for example, 100 μm in average particle size.
m or less. The average particle size means a particle size at which the cumulative weight with respect to the total particle weight becomes 50% (usually referred to as D50). Although the particle shape is not particularly limited, the powder is appropriately flattened to obtain desired electromagnetic wave absorption characteristics. For example, if the aspect ratio is 10 or more,
More preferably, it is set to 25 or more, so that 10 GH
Good absorption capacity is obtained at a frequency equal to or lower than z.
【００１５】そして、この粉末は、上述した金属原料を
溶解したものを例えば水噴霧法、ガス噴霧法、真空噴霧
法等によってアトマイズ粉とし、さらに、このアトマイ
ズ粉をアトライタ等を用いて押し潰して偏平化すること
により、製造することができる。また、偏平化処理をし
た後、さらに所定の熱処理（例えば温度５００〜１１０
０℃、加熱時間１０〜１００分）を施してもよい。The powder is obtained by dissolving the above-mentioned metal raw material into atomized powder by, for example, a water spray method, a gas spray method, a vacuum spray method, or the like, and further crushing the atomized powder using an attritor or the like. It can be manufactured by flattening. After the flattening process, a predetermined heat treatment (for example, at a temperature of 500 to 110) is performed.
(0 ° C., heating time 10 to 100 minutes).
【００１６】本発明の電磁波吸収体に用いるゴムとして
は、例えば、天然ゴムや、クロロプレンゴム、ポリブタ
ジエンゴム、ポリイソプレンゴム、エチレンプロピレン
ゴム、ブタジエンアクリロニトリルゴム、イソブチレン
イソプレンゴム、及びスチレンブタジエンゴム等の合成
ゴムを用いることができる。また樹脂としては、ポリア
ミド樹脂、エポキシ樹脂、各種ポリエステル樹脂、アク
リル樹脂、ポリ酢酸ビニル樹脂、ポリスチレン樹脂、ポ
リプロピレン樹脂、ポリウレタン樹脂、及びポリカーボ
ネート樹脂等を用いることができる。さらに、塩素化ポ
リエチレン等の熱可塑性エラストマを用いることもでき
る。Examples of the rubber used in the electromagnetic wave absorber of the present invention include synthetic rubbers such as natural rubber, chloroprene rubber, polybutadiene rubber, polyisoprene rubber, ethylene propylene rubber, butadiene acrylonitrile rubber, isobutylene isoprene rubber, and styrene butadiene rubber. Rubber can be used. As the resin, a polyamide resin, an epoxy resin, various polyester resins, an acrylic resin, a polyvinyl acetate resin, a polystyrene resin, a polypropylene resin, a polyurethane resin, a polycarbonate resin, or the like can be used. Further, a thermoplastic elastomer such as chlorinated polyethylene can be used.
【００１７】そして、本発明の電磁波吸収体は、例え
ば、上述のゴム原料や樹脂を軟磁性粉末と混合し、さら
に所定の可塑剤や安定剤等を添加して攪拌したものを、
一対のロールの隙間に装入し、これを圧延することによ
り製造することができる。この場合に電磁波吸収体はシ
ート状に成形されるが、この他に、上述した混合物を押
出成形、圧縮成形、あるいは射出成型等して、所定の形
態に成形することもできる。また、加硫剤を添加するこ
とによって加硫を行ってもよい。なお、この電磁波吸収
体には、軟磁性粉末が５〜６５体積％の割合で含有され
ていることが好ましい。軟磁性末の含有量が５体積％以
下であると、電磁波吸収体の電磁波吸収能が低下するか
らであり、６５体積％を超えると粉末を基体のゴムや樹
脂に保持できなくなるからである。The electromagnetic wave absorber of the present invention is obtained, for example, by mixing the above rubber material or resin with a soft magnetic powder, further adding a predetermined plasticizer or stabilizer, and stirring the mixture.
It can be manufactured by charging a gap between a pair of rolls and rolling the roll. In this case, the electromagnetic wave absorber is formed into a sheet shape. Alternatively, the above-described mixture can be formed into a predetermined form by extrusion molding, compression molding, injection molding, or the like. In addition, vulcanization may be performed by adding a vulcanizing agent. The electromagnetic wave absorber preferably contains soft magnetic powder at a ratio of 5 to 65% by volume. If the content of the soft magnetic powder is 5% by volume or less, the electromagnetic wave absorbing ability of the electromagnetic wave absorber decreases, and if it exceeds 65% by volume, the powder cannot be held by the base rubber or resin.
【００１８】[0018]
【実施例】実施例１〜４、比較例１、２ １．軟磁性粉末の製造 表１に示す成分組成を有するＣｒを含むＦｅ基合金を溶
解し、水噴霧法によりアトマイズ粉を製造し球状粉とし
た。また、一部の試料については、球状粉をアトライタ
に装入して押し潰し、所定のアスペクト比を有する偏平
な鱗片状粉末とした。さらに、これらの球状粉や鱗片状
粉末について、不活性ガス雰囲気中で７００℃×６０分
の焼鈍処理を施した。なお、実施例３はＪＩＳに規格す
るＳＵＳ４１０Ｌを、実施例４はＳＵＳ４３０Ｌをそれ
ぞれ用いた。EXAMPLES Examples 1 to 4 and Comparative Examples 1 and 2 Production of Soft Magnetic Powder A Fe-based alloy containing Cr having the component composition shown in Table 1 was dissolved, and atomized powder was produced by a water spray method to obtain spherical powder. For some of the samples, spherical powder was charged into an attritor and crushed to obtain a flat scale-like powder having a predetermined aspect ratio. Further, these spherical powders and scale-like powders were annealed at 700 ° C. for 60 minutes in an inert gas atmosphere. In Example 3, SUS410L conforming to JIS was used, and in Example 4, SUS430L was used.
【００１９】比較のため、センダストを用いて上記と同
様にして鱗片状粉末を製造した。これを比較例１とす
る。また、カルボニル法により製造したＦｅ球状粉を用
いた。これを比較例２とする。なお、上記各粉末の平均
粒径（Ｄ５０値：全粒子に対する累積個数が５０％とな
るときの平均粒径）は表１に示す値になっている。For comparison, flaky powder was produced using Sendust in the same manner as described above. This is referred to as Comparative Example 1. In addition, Fe spherical powder produced by the carbonyl method was used. This is referred to as Comparative Example 2. The average particle size (D50 value: average particle size when the cumulative number with respect to all particles is 50%) of each of the powders is a value shown in Table 1.
【００２０】[0020]
【表１】 [Table 1]
【００２１】２．電磁波吸収シートの成形 塩素化ポリエチレンと軟磁性粉末を混合し、さらに少量
の可塑剤と安定剤を添加して、これらの混合物をニーダ
で混練した。軟磁性粉末の含有量は、混合物全体に対し
て５５体積％となるように調整した。次いで、この混合
物を、回転する双ロールのロール隙間に装入して圧延
し、厚さ１．０ｍｍの電磁波吸収シートに成形した。2. Formation of Electromagnetic Wave Absorbing Sheet Chlorinated polyethylene and soft magnetic powder were mixed, and a small amount of a plasticizer and a stabilizer were further added, and the mixture was kneaded with a kneader. The content of the soft magnetic powder was adjusted so as to be 55% by volume based on the whole mixture. Next, the mixture was charged into the gap between the rotating twin rolls and rolled to form an electromagnetic wave absorbing sheet having a thickness of 1.0 mm.
【００２２】３．電磁波吸収特性の評価 外径７ｍｍφ×内径３．０４ｍｍφの金属製同軸管の両
端面に、７ｍｍφに加工したシートを貼付し、さらにシ
ートの外側から７ｍｍφの金属板を貼付して裏打ちし
た。この管をネットワークアナライザに装着し、１ポー
トにてＳ11を測定し、ＲL＝−２０×ｌｏｇＳ11の関係
式によって反射減衰量（ＲL）を求めた。3. Evaluation of Electromagnetic Wave Absorption Characteristics A sheet processed to 7 mmφ was attached to both end surfaces of a metal coaxial tube having an outer diameter of 7 mmφ and an inner diameter of 3.04 mmφ, and a 7 mmφ metal plate was attached from the outside of the sheet and backed. Mounting the tube to the network analyzer, the S 11 was measured with 1-port, was determined return loss (R L) by the relationship equation R L = -20 × logS 11.
【００２３】４．電磁波吸収シートの耐食性評価 上記シートについて、ＪＩＳ（Ｚ２３７１）に規定する
塩水噴霧試験を行い、試験後６時間、２４時間、４８時
間、及び９６時間経過後のシートを外観目視して、錆の
発生の有無を判定した。錆の発生がない場合を評価Ａ、
シート表面の一部に錆が発生した場合を評価Ｂ、シート
表面の半分以上に錆が発生した場合を評価Ｃ、シート表
面の全体に錆が発生した場合を評価Ｄとした。評価結果
を表１に示す。4. Evaluation of Corrosion Resistance of Electromagnetic Wave Absorbing Sheet The above sheet was subjected to a salt spray test specified in JIS (Z2371), and after 6 hours, 24 hours, 48 hours, and 96 hours after the test, the sheets were visually observed and rust was generated. Was determined. A case where no rust is generated is evaluated A,
The case where rust occurred on a part of the sheet surface was evaluated as B, the case where rust occurred on at least half of the sheet surface was evaluated as C, and the case where rust occurred on the entire sheet surface was evaluated as D. Table 1 shows the evaluation results.
【００２４】５．電磁波吸収シートのコスト評価 カルボニルＦｅ粉を用いた場合のシートのコストを１０
０とした場合の、各実施例のシートのコストを評価し
た。評価結果を表２に示す。5. Cost evaluation of electromagnetic wave absorbing sheet Cost of sheet when carbonyl Fe powder is used is 10
When set to 0, the cost of the sheet of each example was evaluated. Table 2 shows the evaluation results.
【００２５】[0025]
【表２】 [Table 2]
【００２６】図２、図３及び表１、表２から次のことが
明らかである。 (１)本発明の電磁波吸収体は、球状粉末を用いた場合は
周波数６ＧＨｚ近傍の電磁波を吸収し、鱗片状粉末を用
いた場合は周波数１．８ＧＨｚ近傍の電磁波を吸収し、
いずれの場合も従来品とほぼ同じ周波数の電磁波を吸収
することが可能となっている。その一方で、本発明の電
磁波吸収体は、塩水噴霧試験を９６時間行っても錆の発
生が全くなく、電磁波吸収体の耐食性が大幅に向上して
いる。また、電磁波吸収体のコストは従来品より低下す
るか、あるいはわずかに上昇したにとどまっている。こ
のようなことから、軟磁性粉末としてＣｒ：５〜３５重
量％を含むＦｅ基合金粉末を用いた本発明の優位性が明
らかである。The following is clear from FIGS. 2 and 3 and Tables 1 and 2. (1) The electromagnetic wave absorber of the present invention absorbs electromagnetic waves having a frequency of about 6 GHz when spherical powder is used, and absorbs electromagnetic waves at a frequency of about 1.8 GHz when flaky powder is used,
In each case, it is possible to absorb electromagnetic waves having substantially the same frequency as the conventional product. On the other hand, the electromagnetic wave absorber of the present invention has no rust even when the salt spray test is performed for 96 hours, and the corrosion resistance of the electromagnetic wave absorber is greatly improved. In addition, the cost of the electromagnetic wave absorber is lower than that of the conventional product or slightly increased. From this, the superiority of the present invention using the Fe-based alloy powder containing 5 to 35% by weight of Cr as the soft magnetic powder is apparent.
【００２７】(２)軟磁性粉末として、センダスト粉末を
用いた比較例１、及びＦｅ粉を用いた比較例２の場合
は、塩水噴霧試験を４８時間行ったところ、少なくとも
シート表面の半分以上に錆が発生し、電磁波吸収体の耐
食性が大幅に低下した。(2) In the case of Comparative Example 1 using Sendust powder as the soft magnetic powder and Comparative Example 2 using Fe powder, the salt spray test was performed for 48 hours. Rust was generated, and the corrosion resistance of the electromagnetic wave absorber was significantly reduced.
【００２８】[0028]
【発明の効果】以上の説明で明らかなように、本発明に
よれば、従来の電磁波吸収体に比べて、製品コストをほ
とんど上昇させることなく、電磁波吸収体の耐食性を大
幅に向上させることができる。As is apparent from the above description, according to the present invention, the corrosion resistance of the electromagnetic wave absorber can be significantly improved with almost no increase in product cost as compared with the conventional electromagnetic wave absorber. it can.
【図１】本発明に係る電磁波吸収体を示す断面図であ
る。FIG. 1 is a sectional view showing an electromagnetic wave absorber according to the present invention.
【図２】球状粉末を用いた場合の電磁波吸収体の反射減
衰量と電磁波の周波数との関係を示すグラフである。FIG. 2 is a graph showing the relationship between the return loss of an electromagnetic wave absorber and the frequency of an electromagnetic wave when a spherical powder is used.
【図３】鱗片状粉末を用いた場合の電磁波吸収体の反射
減衰量と電磁波の周波数との関係を示すグラフである。FIG. 3 is a graph showing the relationship between the return loss of an electromagnetic wave absorber and the frequency of an electromagnetic wave when a flaky powder is used.
１ 電磁波吸収体 ２ 軟磁性粉末 ４ ゴム又は樹脂 DESCRIPTION OF SYMBOLS 1 Electromagnetic wave absorber 2 Soft magnetic powder 4 Rubber or resin
───────────────────────────────────────────────────── フロントページの続き Ｆターム(参考） 4F100 AB02A AB04A AB04K AB13A AB31A AK01A AN00A BA01 CA20H CA20K DE01 DE01A GB41 JB02 JD08 YY00A 5E040 AA11 AA19 BB03 BB06 CA13 NN01 NN04 5E041 AA11 AA19 BB03 BB06 CA06 NN01 NN04 5E321 BB32 BB33 BB51 BB53 GG11 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F100 AB02A AB04A AB04K AB13A AB31A AK01A AN00A BA01 CA20H CA20K DE01 DE01A GB41 JB02 JD08 YY00A 5E040 AA11 AA19 BB03 BB06 CA13 NN01 NN04 5E041 AA11 BB03 BB03 BB03 BB03 GG11
Claims (3)
から成る軟磁性粉末がゴム又は樹脂に分散して成ること
を特徴とする高耐食性電磁波吸収体。1. A highly corrosion-resistant electromagnetic wave absorber comprising a soft magnetic powder composed of an Fe-based alloy containing 5 to 35% by weight of Cr dispersed in rubber or resin.
３５重量％のフェライト系ステンレス鋼又はマルテンサ
イト系ステンレス鋼の粉末であることを特徴とする請求
項１に記載の高耐食性電磁波吸収体。2. The soft magnetic powder has a Cr content of 10 to 10.
The high corrosion resistant electromagnetic wave absorber according to claim 1, wherein the powder is 35% by weight of ferrite stainless steel or martensitic stainless steel powder.
で含有されていることを特徴とする請求項１又は２に記
載の高耐食性電磁波吸収体。3. The high corrosion resistant electromagnetic wave absorber according to claim 1, wherein the soft magnetic powder is contained at a ratio of 5 to 65% by volume.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11002297A JP2000200990A (en) | 1999-01-07 | 1999-01-07 | High corrosion resistant microwave absorber |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11002297A JP2000200990A (en) | 1999-01-07 | 1999-01-07 | High corrosion resistant microwave absorber |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2000200990A true JP2000200990A (en) | 2000-07-18 |
Family
ID=11525443
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11002297A Withdrawn JP2000200990A (en) | 1999-01-07 | 1999-01-07 | High corrosion resistant microwave absorber |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2000200990A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003068510A (en) * | 2001-08-29 | 2003-03-07 | Sanyo Special Steel Co Ltd | Powder for electromagnetic wave absorbing material |
| JP2007008982A (en) * | 2005-06-28 | 2007-01-18 | Fujikura Kasei Co Ltd | Electric wave absorbing coating composition and coated article |
| US7544427B2 (en) | 2004-01-19 | 2009-06-09 | Incorporated National University Iwate University | Woody electric-wave-absorbing building material |
| KR101007462B1 (en) | 2007-03-23 | 2011-01-12 | 가부시키가이샤 고베 세이코쇼 | Electrically conductive resin painted metal sheet |
| CN106957985A (en) * | 2017-04-28 | 2017-07-18 | 桂林电子科技大学 | A kind of DyHoFe electromagnetic wave absorbing materials and preparation method thereof |
-
1999
- 1999-01-07 JP JP11002297A patent/JP2000200990A/en not_active Withdrawn
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003068510A (en) * | 2001-08-29 | 2003-03-07 | Sanyo Special Steel Co Ltd | Powder for electromagnetic wave absorbing material |
| US7544427B2 (en) | 2004-01-19 | 2009-06-09 | Incorporated National University Iwate University | Woody electric-wave-absorbing building material |
| JP2007008982A (en) * | 2005-06-28 | 2007-01-18 | Fujikura Kasei Co Ltd | Electric wave absorbing coating composition and coated article |
| KR101007462B1 (en) | 2007-03-23 | 2011-01-12 | 가부시키가이샤 고베 세이코쇼 | Electrically conductive resin painted metal sheet |
| CN106957985A (en) * | 2017-04-28 | 2017-07-18 | 桂林电子科技大学 | A kind of DyHoFe electromagnetic wave absorbing materials and preparation method thereof |
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