JPS62171101A - Composite magnet material - Google Patents

Composite magnet material

Info

Publication number
JPS62171101A
JPS62171101A JP61012063A JP1206386A JPS62171101A JP S62171101 A JPS62171101 A JP S62171101A JP 61012063 A JP61012063 A JP 61012063A JP 1206386 A JP1206386 A JP 1206386A JP S62171101 A JPS62171101 A JP S62171101A
Authority
JP
Japan
Prior art keywords
nylon
powder
magnetic powder
magnetic
desirable
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.)
Granted
Application number
JP61012063A
Other languages
Japanese (ja)
Other versions
JPH0467761B2 (en
Inventor
Tadao Katahira
片平 忠夫
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Tokin Corp
Original Assignee
Tohoku Metal Industries Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Tohoku Metal Industries Ltd filed Critical Tohoku Metal Industries Ltd
Priority to JP61012063A priority Critical patent/JPS62171101A/en
Publication of JPS62171101A publication Critical patent/JPS62171101A/en
Publication of JPH0467761B2 publication Critical patent/JPH0467761B2/ja
Granted legal-status Critical Current

Links

Classifications

    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01FMAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
    • H01F1/04Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
    • H01F1/06Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys in the form of particles, e.g. powder
    • H01F1/08Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys in the form of particles, e.g. powder pressed, sintered, or bound together
    • H01F1/083Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys in the form of particles, e.g. powder pressed, sintered, or bound together in a bonding agent

Abstract

PURPOSE:To improve the filling rate of fluid magnetic powder of raw material during the molding and magnetic characteristic after molding by executing surface processing with organic metal compound having stearoil group to magnetic powder of the magnetic material among the composite magnet material consisting of nylon and magnetic powder before mixing and kneading them. CONSTITUTION:A material is composed of nylon of 3-20wt%, magnetic powder of 79.8-95wt% having completed the surface processing with organic metal compound having the stearoil group of 0.1-2wt% and lubricant of 0.1-5wt%. As the nylon resin, 6-nylon or 6,6-nylon is desirable in case the heat resistance is required or 12-nylon is also desirable in case the size accuracy and impact resistance are required. As the format, powder is desirable. For the magnetic powder, the power of alnico is used as the permanent magnet powder and the powder of permalloy is used as the powder having high permeability. The tristearyli-propoxythitane is desirable as the organic metal compound. The adequate value of such additive is about 1wt%. As the lubricant, zinc stearine acid is desirable and it is added in the range of 0.1-5wt%.

Description

【発明の詳細な説明】 p1下余白 磁石の材料に関する。[Detailed description of the invention] p1 bottom margin Regarding magnet materials.

(従来の技術) 熱可塑性樹脂と磁性粉末を混合、混練し、射出成形する
ことによって得られるいわゆるプラスチック磁石は、複
雑な形状が後加工なしで得られること、量産性に優れる
こと9寸法精度の良好なこと、焼結磁石の欠点であるも
ろさがないことなどの特長のため近年様々の用途に用い
られてきている。また、プラスチック磁石の材料として
用いられる樹脂としては、成形時の成形特性などを考慮
して溶融度の比較的低いものが使用されてきている。
(Prior art) So-called plastic magnets, which are obtained by mixing and kneading thermoplastic resin and magnetic powder and then injection molding, have the following advantages: complex shapes can be obtained without post-processing, they are excellent in mass production, and they have excellent dimensional accuracy. In recent years, it has been used for various purposes because of its good properties and lack of brittleness, which is a disadvantage of sintered magnets. Further, as resins used as materials for plastic magnets, resins with a relatively low melting degree have been used in consideration of molding characteristics during molding.

(発明が解決しようとする問題点) 従来のプラスチック磁石と通常の焼結磁石と比較した場
合、磁性粉末の結合材料としてのプラスチックへの流動
性が悪かったり、成形品への磁性粉末の充填率が855
重量%しかならないうえ。
(Problems to be solved by the invention) When compared with conventional plastic magnets and ordinary sintered magnets, the fluidity of magnetic powder into plastic as a binding material is poor, and the filling rate of magnetic powder into molded products is poor. is 855
It's only a percentage by weight.

磁性粉末を混合混練した素材の溶融粘度が極度に上昇し
てしまい、成形上の困難性、成形後における磁石粉末の
配向が不充分になったりするうえ。
The melt viscosity of the material mixed and kneaded with magnetic powder increases extremely, making it difficult to mold and causing insufficient orientation of the magnetic powder after molding.

成形後のプラスチック磁石としての磁気特性の点で劣る
ものにならざるを得なかった。
After molding, the plastic magnet had inferior magnetic properties.

(問題点を解決するだめの手段) 本発明は上記のような、fラスチック磁石形成用に従来
使用されてきた材料における。成形時の素材の流動性の
悪さ並びに磁性粉末の充填率の悪さ、ひいては成形後の
磁気特性の悪さを改良することを目的とするものである
。本発明においては。
(Another Means for Solving the Problems) The present invention relates to materials conventionally used for forming f-plastic magnets, such as those described above. The purpose is to improve the poor fluidity of the material during molding, the poor filling rate of magnetic powder, and ultimately the poor magnetic properties after molding. In the present invention.

基本材料としてのナイロンと磁性粉末とからなる複合磁
石用材料のうちの磁性材料を、混合及び混練する前に、
その磁性粉末をステアロイル基を有する有機金属化合物
で表面処理することを内容とするものである。更に磁石
の成形に際して高級脂肪酸塩やワックス等の滑剤を添加
する。
Before mixing and kneading the magnetic material of the composite magnet material consisting of nylon as the basic material and magnetic powder,
The purpose of this method is to surface-treat the magnetic powder with an organometallic compound having a stearoyl group. Furthermore, a lubricant such as a higher fatty acid salt or wax is added when forming the magnet.

即ち更に詳しくは、ナイロンを3〜20重量%。That is, more specifically, 3 to 20% by weight of nylon.

ステアロイル基を有する有機金属化合物o、 i〜2重
量%で予め表面処理をした磁性粉末を79.8〜95重
量%及び滑剤を0.2〜5重量%混合並びに混練してな
る複合磁石用材料を提供するものでちる。
Composite magnet material prepared by mixing and kneading 79.8 to 95% by weight of magnetic powder whose surface has been previously treated with ~2% by weight of an organometallic compound having a stearoyl group and 0.2 to 5% by weight of a lubricant. This is what we offer.

本発明で用いられるナイロン樹脂としてはたとえば6−
ナイロン、6,6−ナイロン、 6.10−ナイロン、
11−ナイロン、12−ナイロン等が挙げられるが、比
較的耐熱性を要求される場合は6−ナイロン、6,6−
ナイロンが好ましく1寸法精度。
Examples of the nylon resin used in the present invention include 6-
Nylon, 6,6-nylon, 6.10-nylon,
Examples include 11-nylon and 12-nylon, but when relatively heat resistance is required, 6-nylon and 6,6-nylon are used.
Nylon is preferred, with one dimension accuracy.

耐衝撃性等が要求される場合は12−ナイロンが好まし
い。形状はパウダー、ベレットのいずれでも使用可能で
あるが混合混線の作業性を考慮するとパウダーが好まし
い。
When impact resistance etc. are required, 12-nylon is preferred. Although either powder or pellet shape can be used, powder is preferable in consideration of the workability of mixing and crossing wires.

また磁性粉末はいずれの種類でも使用可能であシ、永久
磁石粉末としてはSrフェライト、Baフェライト、希
土類コバルト、アルニコ等の粉末が使用され、高透磁率
粉末としてはン7トフェライト。
Any type of magnetic powder can be used; permanent magnet powders include powders of Sr ferrite, Ba ferrite, rare earth cobalt, alnico, etc., and high magnetic permeability powders include N7 ferrite.

カルブニル鉄、センダスト、ツクーマロイ等ノ粉末が挙
げられる。
Examples include powders such as carbunyl iron, sendust, and tsukumaloy.

有機金属化合物としては一般式(RO)4−n−Tl−
8tn(RO,はアルコキシ基、Stはステロイル基9
nは1〜3の整数)で示される化合物が挙げられるが。
The organometallic compound has the general formula (RO)4-n-Tl-
8tn (RO, is an alkoxy group, St is a steroyl group 9
n is an integer of 1 to 3).

好ましくはトリステアリルi−fロポキンチタンである
。この添加量の適正値は磁性粉末の比表面積9表面活性
度によって変わるが2通常はO91〜2重量係であシ、
2重量%を越えても効果は増加せず、コスト的に不利と
なるので、最も好ましくは1重量%前後である。
Preferred is tristearyl i-f lopoquin titanium. The appropriate value for this addition amount varies depending on the specific surface area of the magnetic powder.
If it exceeds 2% by weight, the effect will not increase and it will be disadvantageous in terms of cost, so it is most preferably around 1% by weight.

まだ滑剤としてはポリエチレンワックス、高級脂肪酸及
びその塩、 DOPのような可塑剤がいずれも使用でき
るが、好ましくはステアリン酸塩、特に好ましくはステ
アリン酸亜鉛である。これらは0.1〜5重量重量節囲
で添加されるが、0.1重量%以下では効果が認められ
ず、5重量%を越える場合は機械的強度が低下するので
好ましくない。
As the lubricant, any of polyethylene wax, higher fatty acids and their salts, and plasticizers such as DOP can be used, but stearate is preferred, and zinc stearate is particularly preferred. These are added in an amount of 0.1 to 5% by weight, but if it is less than 0.1% by weight, no effect is observed, and if it exceeds 5% by weight, the mechanical strength decreases, which is not preferable.

(作用) 本発明の特徴である磁性粉末の表面処理を行うと、樹脂
2例えばナイロンと磁性粉末とが溶融状態になったとき
に、磁性粉末の表面と素材としてのナイロンとの間の摩
擦抵抗が低下し、複合体全体としての溶融粘度も低下す
るので多量に磁性粉でなく、磁場中での磁性粉末の配向
度も著しく改善されることにある。更に高級脂肪酸塩ワ
ックス等の滑剤を加えることによ92表面処理剤との相
乗効果によって成形性、配向度が一層改善されると共に
、成形加工時の離型性も改善されひいては金型の摩耗の
減少にも効果を及ぼすこととなる。
(Function) When the surface treatment of the magnetic powder, which is a feature of the present invention, is performed, when the resin 2, for example, nylon, and the magnetic powder are in a molten state, the frictional resistance between the surface of the magnetic powder and the nylon material Since the melt viscosity of the composite as a whole is also lowered, there is no need to use a large amount of magnetic powder, and the degree of orientation of the magnetic powder in a magnetic field is also significantly improved. Furthermore, by adding a lubricant such as higher fatty acid salt wax, the moldability and degree of orientation are further improved due to the synergistic effect with the 92 surface treatment agent, and the mold releasability during molding is also improved, which in turn reduces mold wear. This will also have an effect on the reduction.

(実施例) 以下に本発明の実施例を比較例と対比しつつ説明する。(Example) Examples of the present invention will be described below in comparison with comparative examples.

以下余日 表−1の組成を以下の条件で混合、混練し、−!!レッ
トを得たが以下の条件に限定されないことは勿論である
The composition shown in Table 1 below is mixed and kneaded under the following conditions, and -! ! Of course, the conditions are not limited to the following conditions.

(1)表面処理剤はクー・クーミキサーで20%n−ヘ
キサン溶液として磁性粉末と混合し、120℃XIHr
乾燥を行った。(但し希土類は真空引をしながら乾燥し
た。) (2)磁性粉末とナイロン、滑剤の混合はスーパーミキ
サーで10 min行った。
(1) The surface treatment agent was mixed with magnetic powder as a 20% n-hexane solution in a Ku-Ku mixer, and heated to 120°C
It was dried. (However, the rare earths were dried under vacuum.) (2) The magnetic powder, nylon, and lubricant were mixed using a super mixer for 10 minutes.

(3)混練は二軸混練押出機を使用した。(3) A twin-screw kneading extruder was used for kneading.

温度 12−ナイロン−220℃、6−ナイロン240
℃ 表−1の材料の評価は下記により行つた。
Temperature 12-nylon-220℃, 6-nylon 240
℃ The materials shown in Table 1 were evaluated as follows.

(1)成形性 温度 12−ナイロン −270℃、6−ナイロン29
0℃ 圧力 70kg/crn2 成形磁場 120000e 上記の条件でφ30×φ10×6の成形品について外観
を観察した。
(1) Formability temperature 12-nylon -270°C, 6-nylon 29
0°C Pressure 70kg/crn2 Molding magnetic field 120000e The appearance of the molded product of φ30×φ10×6 was observed under the above conditions.

(2)流動性 下辺の直径が5椙上辺の直径が3咽高さ2.5mのスパ
イラルフロー金型を用いテストした。(温度280℃ 
圧カフ 0 kg/c1n)(3)  曲げ強度 定法
による (4)磁気特性 定法による 以下余日 (効果) 以上の如く本発明による複合磁石用材料は、複合磁石に
ある磁性材料の成形時における樹脂との摩擦抵抗を低下
せしめる表面処理を予め施してなるので、成形時の樹脂
内での溶融性が飛躍的に向上し、結果的には磁性材料の
充填率が向上する。
(2) Fluidity A test was conducted using a spiral flow mold with a lower diameter of 5 m and an upper diameter of 3 m and a height of 2.5 m. (Temperature 280℃
Pressure cuff 0 kg/c1n) (3) Bending strength According to the standard method (4) Magnetic properties According to the standard method Since the surface treatment is applied in advance to reduce the frictional resistance with the magnetic material, the meltability within the resin during molding is dramatically improved, and as a result, the filling rate of the magnetic material is improved.

また併用する滑剤の作用は前記の摩擦抵抗の低下に対し
相乗効果をもたらし、溶融状態での流動性が著るしく向
上されるとともに、成形性も改良され磁石の完成時には
磁性粉末の配向性が改善されかつ磁気特性にも改良され
た磁石を形成することができる材料を提供することがで
きる。
In addition, the action of the lubricant used in combination has a synergistic effect on the reduction of frictional resistance mentioned above, and the fluidity in the molten state is significantly improved, as well as the formability is improved, and the orientation of the magnetic powder is improved when the magnet is completed. Materials can be provided that can form magnets with improved magnetic properties.

手続補正書(自発) 昭和27年ノ月2夕臼 1、事件の表示 昭和61年特許願第12063号 2、発明の名称  複合磁石用材料 6、補正をする者 事件との関係  特許出願人 4、代理人 〒105 住 所 東京都港区西新橋1丁目4番10号(2)明a
害発明の詳細な説明の項     、−一′  ニー°
ニー 61.3.25 ’> 6、補正の内容 (1)特許請求の範囲 (別紙のとおり)(2)発明の
詳細な説明 明細書中 1)2頁下から8行目「溶融度」ヲ「溶融粘度」と訂正
する。
Procedural amendment (spontaneous) Nozuki 2, 1950, Yuusu 1, Indication of the case, 1988 Patent Application No. 12063 2, Title of invention: Composite magnet material 6, Person making the amendment Relationship to the case: Patent applicant 4 , Agent 105 Address 1-4-10 Nishi-Shimbashi, Minato-ku, Tokyo (2) Mei-a
Detailed explanation of the harmful invention, -1'nee°
61.3.25 '> 6. Contents of the amendment (1) Scope of claims (as attached) (2) Detailed description of the invention 1) "Degree of melting" on the 8th line from the bottom of page 2 Correct it to "melt viscosity."

2)2頁下から5行目乃至3頁4行目までを下記のとお
9訂正する。
2) Make the following 9 corrections from the 5th line from the bottom of page 2 to the 4th line of page 3.

記 従来のプラスチック磁石では磁性粉末を結合材料として
のプラスチックに多量に混合、混練すると得られる複合
体の溶融粘度が著しく上昇して成形が困難となるため、
磁性粉末の充填率は85チ(重量)程度に制約される。
In conventional plastic magnets, when a large amount of magnetic powder is mixed and kneaded with plastic as a binding material, the melt viscosity of the resulting composite increases significantly, making it difficult to mold.
The filling rate of the magnetic powder is limited to about 85 inches (weight).

又溶融粘度の上昇は磁性粉末の配向を阻害するため磁気
特性は焼結磁石に比較して劣るものにならざるを得なか
った。
Furthermore, since the increase in melt viscosity inhibits the orientation of magnetic powder, the magnetic properties are inevitably inferior to those of sintered magnets.

3)3頁8行目「悪」(2カ所)並びに同9行目「悪」
をすべて「低」と訂正する。
3) Page 3, line 8 “evil” (2 locations) and line 9 “evil” on page 3
Correct all to "low".

4)4頁下から2行目「ステロイル」ヲ「ステアロイル
」と訂正する。
4) On the second line from the bottom of page 4, correct "steroyl" to "stearoyl".

5)5頁1行目「トリステアリル」全「トリステアロイ
ル」と訂正する。
5) On page 5, line 1, "tristearyl" is corrected to "tristearoyl."

6)7頁表−1の3行目、9行目並びに同下から4行目
「トリステアリル」ヲ「トリステアコイル」と訂正する
6) In the 3rd and 9th lines of Table 1 on page 7, and the 4th line from the bottom, "tristearyl" is corrected to "tristeacoil."

7)11頁5行目「樹脂内での溶融性」ヲ「複合体の流
動性」と訂正する。
7) On page 11, line 5, "meltability within the resin" is corrected to "fluidity of the composite."

8)1】頁10行目「完成時」ヲ「成形時」と訂正する
8) 1] In the 10th line of the page, "at the time of completion" is corrected to "at the time of molding".

(別紙) 特許請求の範囲 (1)ナイロン3〜20重量%、磁性粉末798〜95
チ。
(Attachment) Claims (1) Nylon 3-20% by weight, magnetic powder 798-95
blood.

特徴とする複合磁性材料。Composite magnetic material with characteristics.

(2)前記磁性粉末がフェライト磁石粉末である特許請
求の範囲第1項記載の複合磁石用材料。
(2) The composite magnet material according to claim 1, wherein the magnetic powder is ferrite magnet powder.

(3)前記磁性粉末が希土類コバルト磁石粉末である特
許請求の範囲第1項記載の複合磁石用材料。
(3) The composite magnet material according to claim 1, wherein the magnetic powder is rare earth cobalt magnet powder.

(4)前記有機金属化合物が0.5〜2.0重量係であ
る特許請求の範囲第1項記載の複合磁石用材料。
(4) The composite magnet material according to claim 1, wherein the organometallic compound has a weight coefficient of 0.5 to 2.0.

(5)前記滑剤がステアリン酸亜鉛である特許請求の範
囲第1項記載の複合磁石用材料。
(5) The composite magnet material according to claim 1, wherein the lubricant is zinc stearate.

Claims (5)

【特許請求の範囲】[Claims] (1)3〜20重量%のナイロンと、0.1〜2重量%
のステアルロイ基を有する有機金属化合物で表面処理を
した79.8〜95重量%の磁性粉末及び0.1〜5重
量%の滑剤とからなることを特徴とする複合磁石用材料
(1) 3-20% by weight of nylon and 0.1-2% by weight
1. A composite magnet material comprising 79.8 to 95% by weight of magnetic powder surface-treated with an organometallic compound having a stearalloy group and 0.1 to 5% by weight of a lubricant.
(2)前記磁性粉末がフェライト磁石粉末である特許請
求の範囲第1項記載の複合磁石用材料。
(2) The composite magnet material according to claim 1, wherein the magnetic powder is ferrite magnet powder.
(3)前記磁性粉末が希土類コバルト磁石粉末である特
許請求の範囲第1項記載の複合磁石用材料。
(3) The composite magnet material according to claim 1, wherein the magnetic powder is rare earth cobalt magnet powder.
(4)前記有機金属化合物が0.5〜1.5重量%であ
る特許請求の範囲第1項記載の複合磁石用材料。
(4) The composite magnet material according to claim 1, wherein the organometallic compound is contained in an amount of 0.5 to 1.5% by weight.
(5)前記滑剤がステアリン酸亜鉛である特許請求の範
囲第1項記載の複合磁石用材料。
(5) The composite magnet material according to claim 1, wherein the lubricant is zinc stearate.
JP61012063A 1986-01-24 1986-01-24 Composite magnet material Granted JPS62171101A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP61012063A JPS62171101A (en) 1986-01-24 1986-01-24 Composite magnet material

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP61012063A JPS62171101A (en) 1986-01-24 1986-01-24 Composite magnet material

Publications (2)

Publication Number Publication Date
JPS62171101A true JPS62171101A (en) 1987-07-28
JPH0467761B2 JPH0467761B2 (en) 1992-10-29

Family

ID=11795141

Family Applications (1)

Application Number Title Priority Date Filing Date
JP61012063A Granted JPS62171101A (en) 1986-01-24 1986-01-24 Composite magnet material

Country Status (1)

Country Link
JP (1) JPS62171101A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01105505A (en) * 1987-10-17 1989-04-24 Tokin Corp Manufacture of compound magnet composite

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01105505A (en) * 1987-10-17 1989-04-24 Tokin Corp Manufacture of compound magnet composite

Also Published As

Publication number Publication date
JPH0467761B2 (en) 1992-10-29

Similar Documents

Publication Publication Date Title
CN105741997A (en) Composite material of injection-molded plastic and soft magnetic powder and preparation method of composite material
WO1993023858A1 (en) Rare earth bond magnet, composition therefor, and method of manufacturing the same
JPS62171101A (en) Composite magnet material
JPH0265103A (en) Resin binder for rare earth-iron and resin magnet using same
JPH0466363B2 (en)
JPS6286803A (en) Manufacture of compound magnet
JP2767244B2 (en) Method for producing composite magnet composition
JPS6191254A (en) Wrist watch case
JPS62259404A (en) Composite magnetic material
JPS595218B2 (en) How to make plastic magnets
JPH04257203A (en) Plastic magnet composite
JPS63248101A (en) Composition for plastic magnet
JPH03270201A (en) Composite magnetic material and plastic magnet
Hung et al. Effects of additives on the orientation and strength of plastic ferrite magnet
JPS58158903A (en) Combined magnetic material
JPH0366106A (en) Thin-walled cylindrical rare earth-fe-b series bond magnet and manufacture thereof
JPS62211902A (en) Anisotropic composite magnet
JPH03207761A (en) Composition for synthetic resin magnet
JP2756860B2 (en) Materials for polyamide plastic magnets
JPS6310502A (en) Magnetic material composition
JP3121875B2 (en) Plastic magnet composition
JPS63168004A (en) Resin magnet with excellent corrosion-resisting property
JPS63299106A (en) Plastic magnetic material
JPH0360101A (en) Resin-bonded permanent magnet
JPS60216524A (en) Manufacture of permanent magnet

Legal Events

Date Code Title Description
LAPS Cancellation because of no payment of annual fees