JPH0534401B2

JPH0534401B2 -

Info

Publication number: JPH0534401B2
Application number: JP60195582A
Authority: JP
Inventors: Kunio Okimoto; Tomio Sato; Toshio Yamakawa
Original assignee: Agency of Industrial Science and Technology
Current assignee: National Institute of Advanced Industrial Science and Technology AIST
Priority date: 1985-09-05
Filing date: 1985-09-05
Publication date: 1993-05-24
Also published as: JPS6270503A

Description

[Detailed description of the invention]

［産業上の利用分野］本発明は、Zn−22Al超塑性合金粉末とフエラ
イト粉末との混合物にプラスチツクを含浸させて
成る複合磁性材料及びその成形方法に関するもの
である。［従来の技術］磁性材料は、一般に100Oe程度以上の抗磁力を
有する硬磁性材料と、それ以下の抗磁力を有する
軟磁性材料に区別される。硬磁性材料は、磁石材
料とも呼ばれ、フエライト磁石、燒結アルニコ磁
石、希土類コバルト磁石等がある。用途として
は、電気機器、各種計測器、通信機器、オーデイ
オ機器等の他、付着用磁石や玩具類などに広く使
用されている。一方、軟磁性材料は、トランス、磁気ヘツド、
制振材、電磁波吸収材などとして使用されてい
る。近年、重厚長大よりも軽薄短小であることに趣
が置かれるようになり、硬磁性材料の分野におい
ても製品の小型化、高性能化、複雑形状化に対す
る要請が高まつている。この要請をかなえるため
の硬磁性材料の製造方法の一つとして、プラスチ
ツク磁石やゴム磁石成形において代表される射出
成形法がある。射出成形法は、複雑な形状を有する成形品を一
工程で製造できるので、最終部品形状に極めて近
い形状・寸法に加工する方法として優れている。
しかし、射出成形法において用いられる樹脂は一
般に絶縁性であるから、それによつて製造される
プラスチツク磁石は、近年問題となつている電磁
波吸収材など、導電性を要求される用途には本質
的に適さない。また、近年は振動公害が社会的な問題となつて
おり、これを解決するための適当な振動吸収材・
制振材の開発が望まれている。そこで、これらの問題を解決するために、プラ
スチツクの代替としてZn−22Al超塑性合金粉末
を用いる新しい複合磁性材料及びその成形方法
（特開昭62−20845号）を開示したが、この場合、
磁性材料粉末の配合割合が多くなると成形体の強
度が劣り、特に50重量％程度以上になると、成形
そのものは可能であるけれども成形体の強度が非
常に劣るという欠点があることがわかつた。［発明が解決しようとする課題］本発明の技術的課題は、上述の射出成形法によ
るプラスチツク磁石の絶縁性の問題と、Zn−
22Al超塑性合金粉末と磁性材料粉末から成る複
合磁性材料において、磁性材料粉末の配合割合が
多くなると成形体の強度が劣るという欠点を同時
に解消し、導電性、制振性及び電磁波シールド性
に富み、機械的性質の優れた新規な複合磁性材料
及びその成形方法を得ることにある。［課題を解決するための手段、作用］上記課題を解決するため、本発明者は、配合割
合が50重量％以下の磁性材料粉末とZn−22Al超
塑性合金粉末からなる複合磁性材料の機械的性質
を、適切な強化手段によつて一層改善すべく、各
種強化手段を試み、その結果、プラスチツクの含
浸が有効であることを確かめた。本発明は、かかる知見に基づくものであつて、
その複合磁性材料の特徴とするところは、0.1〜
50重量％のフエライト粉末と残部がZn−22Al超
塑性合金粉末なる配合割合の混合粉末からなる成
形体に、プラスチツクを含浸させた点にある。また、本発明の複合材料成形方法は、0.1〜50
重量％のフエライト粉末と、残部がZn−22Al超
塑性合金粉末からなる混合粉末を、室温〜250℃
の温度下にて、１〜30kgf／mm²なる成形圧で成形
した後、プラスチツクを含浸させ、あるいは、
0.1〜50重量％のフエライト粉末と、残部がZn−
22Al超塑性合金粉末からなる混合粉末を、200〜
250℃の温度下にて、１〜10kgf／mm²なる成形圧
で10〜60分間ホツトプレス成形した後、プラスチ
ツクを含浸させることを特徴とするものである。本発明において用いるフエライト粉末は、上述
するように、0.1〜50重量％が適切である。その
理由は、複合磁性材料の場合、磁性粉末が50重量
％以上になると、成形体の強度が非常に劣るこ
と、トランス、磁気ヘツド、制振材等に利用する
本発明の場合には、50重量％もあれば十分である
こと、フエライト粉末の有する磁気的特性とZn
−22Al超塑性合金粉末の有する成形性、プラス
チツクによる機械的性質の強化程度等を勘案する
と、上記範囲が適切であること、などを挙げるこ
とができる。本発明の複合磁性材料並びにその成形方法にお
いて用いるZn−22Al超塑性合金粉末は、一般に
空気噴霧法もしくはアルゴン噴霧法により製造さ
れる。本発明者は、先にこの超塑性合金粉末を
380℃で30分間の加熱した後に氷水に浸漬して急
冷処理を施すと、超塑性化に対して極めて効果的
であることを見出し、既に特開昭59−157201号と
して提案している。本発明においても、この急冷
処理を施したZn−22Al超塑性合金粉末をいると、
成形体の密度の向上や磁性材料粉末の配合割合を
大きくすることができ、一段と有効である。第１図イは、その成形加工方法を実施する状態
を示すもので、同図において、１はフエライト粉
末、２はZn−22Al超塑性合金粉末、３，４はパ
ンチ、５はダイス、６は成形体に残存している空
孔である。また、第１図ロ成形体に残存している
空孔６にプラスチツクを含浸させた状態を模式的
に示している。磁性材料としては、軟磁性材料としても使用可
能な各種フエライト系磁性材料を用いることが可
能である。以下においては、フエライト粉末とし
て、戸田工業(株)製GP−500を用いた例について説
明する。フエライト粉末とZn−22Al超塑性合金粉末の
配合割合［フエライト粉末の重量÷（フエライト
粉末の重量＋Zn−22Al超塑性合金粉末の重量）×
100％］であるが、Zn−22Al超塑性合金粉末の配
合割合が多い程、成形加工は容易である。一方、フエライト粉末が大である程、磁気特性
は良くなるが、成形体の強度が加工性等で問題が
生ずる。第２図に示したものは冷間成形における
場合の成形圧力とフエライト配合割合を種々変え
た製品につき、成形体を金型から取出した際の成
形状態及び成形体の強度を示したものである。図
中における破壊領域は、成形体を金型から取出し
た際、成形体が破壊していたり（×印）、一部に
亀裂が認められる（△印）ことを示し、それ以外
の領域は成形が可能である領域を表わす。次に、成形が可能である領域の成形体について
JSPM標準４−69で規定されている「金属圧粉体
のラトラ試験法」に準じた試験（試験片１個を使
用）を行うことにより、成形体の重量減少率を測
定した。成形体の成形状態が良好で、しかもラト
ラ試験における重量減少率が10％以下となるもの
を、第２図●印で示し、重量減少率が10％以上と
なるものを○印で示した。本発明の対象とする領
域は、成形領域の内で主として○印で示す領域で
ある。第２図の○印で示した強度的に劣る成形体の強
化を図ることを目的として、Zn−22Al超塑性合
金粉末とフエライト粉末から成る成形体を密閉容
器に入れ、ロータリーポンプで容器内を真空に引
いた後、熱硬化性のエポキシ樹脂（笠井商工(株)製
27−770）を成形体に含浸させた。第３図は成形
圧力が10kgf／mm²の場合における成形体の強度と
フエライトの配合割合を示したものであるが、含
浸処理により強度が大幅に向上することが明らか
である。次に、含浸前の成形体の成形加工条件である
が、これには主要な要素として加工温度、加圧力
及びその作用時間等が考えられる。これらの要素
の内、超塑性材料は所定の温度において大きな延
性と加工力の低減を発現するので、加工温度の適
正な設定が最も重要である。Zn−22Al超塑性合
金粉末の場合、室温においても十分な延性を有す
るものの200〜250℃が適当であり、特に250℃前
後が最適である。成形圧力に関しては、これが小
さすぎると粉末が固化せず、例え固化しても成形
体の強度が劣る。本発明の場合、成形体に含浸す
ることを目的としているので、成形圧力は過度に
大きくする必要はなく、250℃前後で成形する場
合には2.5kgf／mm²〜5.0kgf／mm²であれば十分であ
る。冷間成形の場合には１〜30kgf／mm²である。
加圧力の保持時間に関しては、機械プレスによる
鍛造のように保持時間が瞬時でも一向に差しつか
えないが、ホツトプレス法を用いて加圧時間を長
くすれば、成形体の密度の向上に対して有効であ
る。ただし、Zn−22Al超塑性材は250℃で、60分
間程度以上に渡つて放置すると結晶粒が粗大化し
て、超塑性能が低下する。そのためホツトプレス
法を用いる場合における圧力の保持時間の上限は
60分である。上述のごとき条件下で成形体を製造した後にプ
ラスチツクを含浸すれば、強靭な磁性複合材料と
なる。なお、含浸前の成形体を200〜400℃の温度範囲
で焼結すれば、成形体の強度は向上する。しかし
ながら、含浸作業を行うことにより成形体の強度
が飛躍的に向上するので、この焼結工程は省略し
ても一向に差しつかえない。［実施例］以下本発明の実施例を示す。実施例１平均粒子径が約1μｍであるバリウム・フエラ
イト粉末（戸田工業(株)製GP−500）と空気噴霧法
で製造した44μｍ以下のZn−22Al超塑性合金粉末
の配合割合を10〜70％に変化させ、成形圧力は
10kgf／mm²で一定として冷間成形した。得られた
成形体にエシキシ樹脂（笠井商工(株)製27−770）
を含浸させて得られた磁性材料の機械的強度を第
１表に示す。比較のためにプラスチツクを含浸し
ない場合の結果も併記した。 [Field of Industrial Application] The present invention relates to a composite magnetic material made by impregnating plastic into a mixture of Zn-22Al superplastic alloy powder and ferrite powder, and a method for molding the same. [Prior Art] Magnetic materials are generally classified into hard magnetic materials that have a coercive force of about 100 Oe or more and soft magnetic materials that have a coercive force of less than about 100 Oe. Hard magnetic materials are also called magnetic materials, and include ferrite magnets, sintered alnico magnets, rare earth cobalt magnets, and the like. It is widely used in electrical equipment, various measuring instruments, communication equipment, audio equipment, etc., as well as adhesive magnets and toys. On the other hand, soft magnetic materials are used in transformers, magnetic heads,
Used as vibration damping material, electromagnetic wave absorbing material, etc. In recent years, people have become more interested in products that are light, thin, short, and small rather than heavy, long, and large, and demands for smaller products, higher performance, and more complex shapes are increasing even in the field of hard magnetic materials. One of the methods for manufacturing hard magnetic materials to meet this demand is injection molding, which is typified by the molding of plastic magnets and rubber magnets. Injection molding is an excellent method for producing molded products with complex shapes in one step, so that it can be processed into shapes and dimensions that are extremely close to the final part shape.
However, since the resin used in the injection molding method is generally insulating, the plastic magnets manufactured using it cannot be used in applications that require electrical conductivity, such as electromagnetic wave absorbing materials, which have become a problem in recent years. Not suitable. In addition, in recent years, vibration pollution has become a social problem, and appropriate vibration absorbing materials and materials have been developed to solve this problem.
Development of vibration damping materials is desired. Therefore, in order to solve these problems, a new composite magnetic material using Zn-22Al superplastic alloy powder as a substitute for plastic and a method for molding the same (Japanese Patent Application Laid-Open No. 62-20845) was disclosed.
It has been found that as the blending ratio of magnetic material powder increases, the strength of the molded product deteriorates, and in particular, when it exceeds about 50% by weight, although molding itself is possible, the strength of the molded product is extremely poor. [Problems to be Solved by the Invention] The technical problems of the present invention are to solve the above-mentioned insulation problem of plastic magnets produced by the injection molding method, and to solve the problem of Zn-
In a composite magnetic material consisting of 22Al superplastic alloy powder and magnetic material powder, it simultaneously eliminates the disadvantage that the strength of the compact becomes poor when the blending ratio of magnetic material powder increases, and it has excellent conductivity, vibration damping properties, and electromagnetic shielding properties. The object of the present invention is to obtain a novel composite magnetic material with excellent mechanical properties and a method for molding the same. [Means and effects for solving the problem] In order to solve the above problem, the present inventor has developed a mechanical structure of a composite magnetic material consisting of magnetic material powder and Zn-22Al superplastic alloy powder with a blending ratio of 50% by weight or less. In order to further improve the properties through appropriate reinforcing measures, various reinforcing methods were tried, and as a result, impregnation of plastic was confirmed to be effective. The present invention is based on this knowledge, and includes:
The characteristics of this composite magnetic material are 0.1~
The point is that plastic is impregnated into a compact made of a mixed powder mixture of 50% by weight ferrite powder and the balance Zn-22Al superplastic alloy powder. In addition, the composite material molding method of the present invention has a
A mixed powder consisting of ferrite powder of % by weight and the balance of Zn-22Al superplastic alloy powder was heated at room temperature to 250°C.
After molding at a temperature of 1 to 30 kgf/ ^mm2 , impregnating with plastic, or
0.1 to 50% by weight of ferrite powder and the balance is Zn−
Mixed powder consisting of 22Al superplastic alloy powder, 200 ~
It is characterized by hot press molding at a temperature of 250° C. and a molding pressure of 1 to 10 kgf/mm ² for 10 to 60 minutes, followed by impregnation with plastic. As mentioned above, the ferrite powder used in the present invention is suitably 0.1 to 50% by weight. The reason for this is that in the case of composite magnetic materials, if the magnetic powder content exceeds 50% by weight, the strength of the compact becomes extremely poor. % by weight is sufficient, magnetic properties of ferrite powder and Zn
Considering the formability of the -22Al superplastic alloy powder, the degree of reinforcement of mechanical properties by plastic, etc., the above range is appropriate. The Zn-22Al superplastic alloy powder used in the composite magnetic material of the present invention and its molding method is generally produced by an air atomization method or an argon atomization method. The present inventor previously developed this superplastic alloy powder.
It has been found that heating at 380°C for 30 minutes followed by rapid cooling by immersion in ice water is extremely effective in preventing superplasticization, and has already been proposed in JP-A-59-157201. In the present invention, when Zn-22Al superplastic alloy powder subjected to this rapid cooling treatment is used,
It is possible to improve the density of the compact and increase the blending ratio of magnetic material powder, which is even more effective. Figure 1A shows the state in which the forming method is carried out. In the figure, 1 is ferrite powder, 2 is Zn-22Al superplastic alloy powder, 3 and 4 are punches, 5 is die, and 6 is These are pores remaining in the molded body. Furthermore, FIG. 1B schematically shows a state in which the pores 6 remaining in the molded body are impregnated with plastic. As the magnetic material, it is possible to use various ferrite-based magnetic materials that can also be used as soft magnetic materials. In the following, an example will be described in which GP-500 manufactured by Toda Kogyo Co., Ltd. is used as the ferrite powder. Mixing ratio of ferrite powder and Zn-22Al superplastic alloy powder [weight of ferrite powder ÷ (weight of ferrite powder + weight of Zn-22Al superplastic alloy powder) ×
100%], but the higher the blending ratio of Zn-22Al superplastic alloy powder, the easier the molding process becomes. On the other hand, the larger the ferrite powder is, the better the magnetic properties will be, but problems will arise in the strength of the molded body, workability, etc. Figure 2 shows the molded state and strength of the molded body when the molded body is removed from the mold for products with various cold forming pressures and ferrite compounding ratios. . The fracture area in the figure indicates that the molded product is broken (x mark) or cracks are observed in some parts (△ mark) when the molded product is removed from the mold. represents the area in which this is possible. Next, regarding the molded object in the area where molding is possible.
The weight loss rate of the molded body was measured by conducting a test (using one test piece) according to the "Rator test method for metal green compacts" specified in JSPM Standard 4-69. Molded articles in good molding condition and with a weight loss rate of 10% or less in the rattler test are indicated by ● marks in Figure 2, and those whose weight loss rate is 10% or more are indicated by ○ marks. The area targeted by the present invention is mainly the area indicated by a circle in the molding area. In order to strengthen the compacts with poor strength, which are indicated by circles in Figure 2, the compacts made of Zn-22Al superplastic alloy powder and ferrite powder were placed in a closed container, and the inside of the container was pumped using a rotary pump. After vacuuming, thermosetting epoxy resin (manufactured by Kasai Shoko Co., Ltd.)
27-770) was impregnated into the molded body. FIG. 3 shows the strength of the molded body and the blending ratio of ferrite when the molding pressure is 10 kgf/mm ² , and it is clear that the strength is significantly improved by the impregnation treatment. Next, regarding the molding processing conditions of the molded article before impregnation, the main factors are considered to be processing temperature, pressing force, and its working time. Among these factors, since superplastic materials exhibit large ductility and reduction in working force at a given temperature, appropriate setting of the working temperature is most important. In the case of Zn-22Al superplastic alloy powder, although it has sufficient ductility even at room temperature, a temperature of 200 to 250°C is appropriate, and a temperature of around 250°C is particularly optimal. Regarding the molding pressure, if it is too small, the powder will not solidify, and even if it solidifies, the strength of the molded product will be poor. In the case of the present invention, since the purpose is to impregnate a molded body, the molding pressure does not need to be excessively high, and when molding is performed at around 250°C, it may be 2.5 kgf/mm ² to 5.0 kgf/mm ^2. It is sufficient. In the case of cold forming, it is 1 to 30 kgf/mm ² .
Regarding the holding time of the pressurizing force, there is no problem even if the holding time is instantaneous as in forging with a mechanical press, but if the pressurizing time is extended using the hot press method, it is effective in improving the density of the compact. be. However, if the Zn-22Al superplastic material is left at 250°C for about 60 minutes or more, the crystal grains will become coarser and the superplastic performance will deteriorate. Therefore, when using the hot press method, the upper limit of the pressure holding time is
It is 60 minutes. If a molded body is produced under the conditions described above and then impregnated with plastic, a strong magnetic composite material will be obtained. Note that, if the molded body before impregnation is sintered at a temperature range of 200 to 400°C, the strength of the molded body will be improved. However, since the strength of the molded body is dramatically improved by performing the impregnation operation, there is no harm in omitting this sintering step. [Example] Examples of the present invention will be shown below. Example 1 The blending ratio of barium ferrite powder (GP-500 manufactured by Toda Kogyo Co., Ltd.) with an average particle size of about 1 μm and Zn-22Al superplastic alloy powder with a size of 44 μm or less produced by an air atomization method was 10 to 70. %, the molding pressure is
Cold forming was carried out at a constant pressure of 10 kgf/ ^mm2 . Ethoxy resin (27-770 manufactured by Kasai Shoko Co., Ltd.) is applied to the obtained molded body.
Table 1 shows the mechanical strength of the magnetic material obtained by impregnating it. For comparison, the results without plastic impregnation are also shown.

【表】第１表結果より、プラスチツクを含浸した本発
明の場合には、機械的強度が大幅に向上し、その
有効性が明らかである。なお、機械的高度は円板
圧裂試験における円板圧裂強さで測定した。ここ
で、円板圧裂強さとは、円板の直径方向から加圧
して円板の破壊荷重Ｐを測定し、 σ＝2P／πDH で求めた強度である。ただし、Ｄは試験片の直
径、Ｈは同高さである。実施例２磁性粉末（戸田工業(株)製のSR−５〔平均粒子1μ
ｍのストロンチウム・フエライト粉末〕とMZ−
100〔平均粒子径1.10μｍのMn−Zn系フエライト
粉末〕）と空気噴霧法で製造した44μｍ以下のZn
−22Al超塑性合金粉末の配合割合を０重量％、
20重量％とし、室温のもとで成形圧力10kgf／mm²
でこれらの混合粉末を成形した後に、実施例１と[Table] From the results in Table 1, in the case of the present invention impregnated with plastic, the mechanical strength is significantly improved, and its effectiveness is clear. In addition, the mechanical height was measured by the disc crush strength in the disc crush test. Here, the disk crushing strength is the strength determined by applying pressure from the diameter direction of the disk, measuring the fracture load P of the disk, and using σ=2P/πDH. However, D is the diameter of the test piece, and H is the same height. Example 2 Magnetic powder (SR-5 manufactured by Toda Kogyo Co., Ltd. [average particle 1μ
strontium ferrite powder] and MZ-
100 [Mn-Zn ferrite powder with an average particle size of 1.10 μm]) and Zn of 44 μm or less produced by air atomization method.
-22Al superplastic alloy powder blending ratio is 0% by weight,
20% by weight, molding pressure 10kgf/mm ² at room temperature
After molding these mixed powders in Example 1 and

【表】同じエポキシ樹脂を含浸させて、制振用の磁性複
合材料を製造した。得られた複合材料の減衰能を
第２表に示す。［発明の効果］以上に述べてきたごとく、本発明によれば、射
出成形法によるプラスチツク磁石の絶縁性の問題
と、Zn−22Al超塑性合金粉末と磁性材料粉末か
ら成る複合磁性材料において、磁性材料粉末の配
合割合が多くなると成形体の強度が劣るという欠
点を同時に解消し、Zn−22Al超塑性合金の特性
であるところの導電性が良好であるという特徴を
そのまま生かし、且つプラスチツクの混合による
強化を図つた複合磁性材料を得ることができる。
この複合磁性材料は、導電性及び制振性に富み、
機械的性質において優れているので、制振材等と
して有効に利用でき、しかもその成形は一般の燒
結体を得ると同じような加圧成形法とその後の含
浸作業により行うことが可能であるために、効率
のよい製造を行うことができる。[Table] A magnetic composite material for vibration damping was manufactured by impregnating it with the same epoxy resin. Table 2 shows the damping capacity of the obtained composite material. [Effects of the Invention] As described above, the present invention solves the problem of insulation of plastic magnets produced by injection molding, and solves the problem of magnetic properties in a composite magnetic material composed of Zn-22Al superplastic alloy powder and magnetic material powder. At the same time, the drawback that the strength of the molded body deteriorates when the blending ratio of material powder increases is eliminated, and the characteristic of Zn-22Al superplastic alloy, which has good electrical conductivity, is taken advantage of, and at the same time, by mixing plastics, A reinforced composite magnetic material can be obtained.
This composite magnetic material is rich in conductivity and vibration damping properties,
Because it has excellent mechanical properties, it can be effectively used as a vibration damping material, etc., and it can be formed using the same pressure forming method and subsequent impregnation work that is used to obtain a general sintered body. Therefore, efficient manufacturing can be performed.

[Brief explanation of the drawing]

第１図イとロは本発明の成形方法と含浸の概略
説明図、第２図は冷間成形における成形体の状態
とラトラ試験の結果を示すグラフ、第３図は成形
体の強度とフエライト粉末の配合割合との関係を
示すグラフである。１……フエライト粉末、２……Zn−22Al超塑
性合金粉末、３，４……パンチ、５……ダイス、
６……成形体の空孔。 Figure 1 A and B are schematic illustrations of the molding method and impregnation of the present invention, Figure 2 is a graph showing the condition of the molded body during cold forming and the results of the rattler test, and Figure 3 is the strength of the molded body and ferrite. It is a graph showing the relationship with the blending ratio of powder. 1... Ferrite powder, 2... Zn-22Al superplastic alloy powder, 3, 4... Punch, 5... Dice,
6...Vacancies in the molded body.

Claims

[Claims] 1 0.1 to 50% by weight of ferrite powder and the balance being Zn
A composite magnetic material made by impregnating plastic into a compact made of a mixed powder of -22Al superplastic alloy powder. 2 After heating at 380℃ for 30 minutes, rapid cooling treatment was performed.
The composite magnetic material according to claim 1, characterized in that it contains Zn-22Al superplastic alloy powder. 3 0.1 to 50% by weight of ferrite powder and the balance
Mixed powder consisting of Zn-22Al superplastic alloy powder,
A method for molding a composite magnetic material, which comprises molding at a molding pressure of 1 to 30 kgf/mm ² at a temperature of room temperature to 250°C, and then impregnating it with plastic. 4 After heating at 380℃ for 30 minutes, rapid cooling treatment was performed.
4. A method for molding a composite magnetic material according to claim 3, characterized in that Zn-22Al superplastic alloy powder is blended. 5 0.1 to 50% by weight of ferrite powder and the balance
Mixed powder consisting of Zn-22Al superplastic alloy powder,
A method for molding a composite magnetic material, which comprises hot press molding at a temperature of 200 to 250°C and a molding pressure of 1 to 10 kgf/ ^mm2 for 10 to 60 minutes, and then impregnating the material with plastic. 6 After heating at 380℃ for 30 minutes, rapid cooling treatment was performed.
A method for molding a composite magnetic material according to claim 5, characterized in that Zn-22Al superplastic alloy powder is blended.