JPH05335123A - Corrosion-proof property improved r-tm-b permanent magnet - Google Patents
Corrosion-proof property improved r-tm-b permanent magnetInfo
- Publication number
- JPH05335123A JPH05335123A JP4136695A JP13669592A JPH05335123A JP H05335123 A JPH05335123 A JP H05335123A JP 4136695 A JP4136695 A JP 4136695A JP 13669592 A JP13669592 A JP 13669592A JP H05335123 A JPH05335123 A JP H05335123A
- Authority
- JP
- Japan
- Prior art keywords
- permanent magnet
- layer
- metal
- metal coating
- coating layer
- 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.)
- Pending
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
- H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
- H01F41/0253—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets
- H01F41/026—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets protecting methods against environmental influences, e.g. oxygen, by surface treatment
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Environmental & Geological Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Hard Magnetic Materials (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、Ｒ−ＴＭ−Ｂ系永久磁
石であって、磁石体表面に３層金属被覆層を設ける事に
より耐食性を著しく改善したものに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an R-TM-B type permanent magnet which has a three-layer metal coating layer on the surface of a magnet body to remarkably improve corrosion resistance.
【０００２】[0002]
【従来の技術】電気・電子機器の高性能・小型化に伴っ
て、その一部分たる永久磁石にも同様の要求が強まって
きた。すなわち以前の最強の永久磁石は希土類・コバル
ト（Ｒ−Ｃｏ）系であったが、近年、より強力なＲ−Ｔ
Ｍ−Ｂ系永久磁石が台頭してきた（特開昭５９−４６０
０８号）。ここにＲはＹをふくむ希土類元素の１種又は
２種以上の組み合わせであり、ＴＭはＦｅ、Ｃｏ等の遷
移金属中心として、一部を他の金属元素又は非金属元素
で置換したもの、Ｂは硼素である。しかし、Ｒ−ＴＭ−
Ｂ系永久磁石は極めて錆やすいという問題点があった。
そのため、耐食性を改善するために、永久磁石表面に耐
酸化性の被覆層を設ける手段がとられてきた。被覆層の
種類としては、金属めっき、耐酸化性樹脂、蒸着法によ
る金属被膜等が提案されており、とりわけ金属めっきは
簡易な処理でＲ−ＴＭ−Ｂ系永久磁石の耐食性を向上す
るものとして注目されている（特開昭６０−５４４０６
号）。金属めっきは、耐酸化性樹脂と比較して表面被覆
層の機械的強度に優れており、また被覆層自体の吸湿性
がほとんどないという長所を有している。しかしなが
ら、耐酸化性樹脂と異なり、金属めっき被覆層表面には
ピンホールが存在するため、被覆層自身の吸湿性の有無
にかかわらず、経時変化に伴い水分がピンホールを通じ
て磁石体に浸透し、腐食劣化を引き起こすという問題が
あった。2. Description of the Related Art With the high performance and miniaturization of electric and electronic devices, the same demands have been placed on permanent magnets which are a part of them. In other words, the strongest permanent magnet before was the rare earth-cobalt (R-Co) system, but in recent years, the stronger RT
MB type permanent magnets have emerged (Japanese Patent Laid-Open No. 59-460).
08). Here, R is one kind or a combination of two or more kinds of rare earth elements including Y, TM is a transition metal center such as Fe or Co, part of which is replaced with another metal element or non-metal element, B Is boron. However, R-TM-
The B type permanent magnet has a problem that it is extremely rusty.
Therefore, in order to improve the corrosion resistance, a measure has been taken to provide an oxidation resistant coating layer on the surface of the permanent magnet. As the type of coating layer, metal plating, oxidation resistant resin, metal coating by vapor deposition method, etc. have been proposed. Especially, metal plating is intended to improve the corrosion resistance of the R-TM-B type permanent magnet by a simple treatment. Attention (Japanese Patent Application Laid-Open No. 60-54406)
issue). Metal plating has an advantage that the surface coating layer has excellent mechanical strength as compared with the oxidation resistant resin, and that the coating layer itself has almost no hygroscopicity. However, unlike the oxidation resistant resin, since there are pinholes on the surface of the metal plating coating layer, regardless of whether the coating layer itself has hygroscopicity, moisture permeates the magnet body through the pinholes with the passage of time, There was a problem of causing corrosion deterioration.
【０００３】この問題を解決するため、現在までに電気
化学的な接触腐食現象を利用した２層金属被覆層の設置
や３層金属被覆層の設置による手法を本出願人は提案し
ている（特願平３−６２５６０号、同３−４８８８５
号）。２層金属被覆層の設置は電気化学的に卑な上層を
犠牲的に腐食させて貴な下層を防食する手法であり、３
層金属被覆層の設置は電気化学的に最も卑な中間層を優
先的に腐食させることにより最も卑な最下層を防食しよ
うとするものである。In order to solve this problem, the present applicant has proposed a method of installing a two-layer metal coating layer or a three-layer metal coating layer by utilizing an electrochemical contact corrosion phenomenon to date ( Japanese Patent Application Nos. 3-62560 and 3-48885.
issue). The installation of the two-layer metal coating layer is a method of sacrificing the electrochemically base upper layer sacrificially to protect the noble lower layer.
The installation of the layer metallization layer is intended to prevent corrosion of the lowest base layer by preferentially corroding the electrochemically lowest base layer.
【０００４】[0004]
【発明が解決しようとする課題】しかしながら、前記し
た電気化学的な接触腐食現象による手法をもってしても
十分な耐食性改善を図ることができず問題となってい
た。とりわけ前記した３層金属被覆層の設置による手法
は、水分が中間層へ確実に浸透することを余儀なくされ
てしまい、耐食性の面で問題視されていた。そこで、本
発明の目的は、信頼性の高い耐食性を改善したＲ−ＴＭ
−Ｂ系永久磁石を提供することにある。However, even with the method based on the above-mentioned electrochemical contact corrosion phenomenon, sufficient corrosion resistance cannot be improved, which is a problem. In particular, the above-mentioned method of installing the three-layer metal coating layer is forced to allow the moisture to permeate into the intermediate layer, which has been regarded as a problem in terms of corrosion resistance. Therefore, an object of the present invention is to provide a highly reliable R-TM with improved corrosion resistance.
-To provide a B-type permanent magnet.
【０００５】[0005]
【課題を解決するための手段】本発明は、重量比でＲ
（ここでＲは、これを含む希土類元素の１種又は２種以
上の組み合わせ）５〜４０％、ＴＭ（ここでＴＭはＦｅ
を主体とする遷移金属であって一部を他の金属元素又は
非金属元素で置換してよい。）５０〜９０％、Ｂ（硼
素）０．２〜８％からなるＲ−ＴＭ−Ｂ系永久磁石の表
面に、電気化学的に貴な順に積層被覆された３種の異な
る金属被覆層を有することを特徴とする耐食性を改善し
たＲ−ＴＭ−Ｂ系永久磁石である。本発明における３種
の異なる金属被覆層としては、最下層がＣｕあるいはＮ
ｉのいずれか金属被覆層、中間層がＮｉあるいはＮｉ−
Ｓのいずれかの金属被覆層、最上層がＮｉ−Ｓ、Ｎｉ−
Ｐ、Ｓｎ、Ｓｎ−Ｐｂ、Ｃｒ、Ｚｎ、Ａｌから選ばれた
１種の金属被覆層が好適である。The present invention is based on the weight ratio of R
(Where R is one or a combination of two or more rare earth elements containing this) 5 to 40%, TM (where TM is Fe)
The transition metal mainly composed of the above may be partially substituted with another metal element or non-metal element. ) Three kinds of different metal coating layers laminated and coated electrochemically in a noble order on the surface of the R-TM-B system permanent magnet composed of 50 to 90% and B (boron) 0.2 to 8% It is an R-TM-B type permanent magnet having improved corrosion resistance. Of the three different metal coating layers in the present invention, the lowest layer is Cu or N.
i is Ni or Ni-
Any of the metal coating layers of S, the uppermost layer is Ni-S, Ni-
One kind of metal coating layer selected from P, Sn, Sn-Pb, Cr, Zn and Al is suitable.
【０００６】素材表面に、電気化学的に貴な金属被覆層
を下層として設け、その上層として卑な金属被覆層を設
けると、両者の腐食電池列の関係から卑な上層がアノー
ド化して陽極効果を発生することにより貴な下層がカソ
ード的に防食される。すなわち電気化学的に貴な順に積
層被覆された３種の異なる金属被覆層に関しては前記防
食効果がより強固なものとなり、水分の中間層への浸透
が防止され、同時に下地も守られるものと考えられる。
本発明は、上記防食作用により、Ｒ−ＴＭ−Ｂ系永久磁
石の耐食性を向上するものである。なお、本発明の金属
被覆層は少なくとも３種、つまり３層あればよく、本発
明の趣旨に従って４層以上の積層としてもよいことは言
うまでもない。本発明において、Ｆｅ、Ｃｏ、Ｎｉ等の
ＴＭの一部を置換する元素は、その添加目的に応じて、
Ｇａ、Ａｌ、Ｔｉ、Ｖ、Ｃｒ、Ｍｎ、Ｚｒ、Ｈｆ、Ｎ
ｂ、Ｔａ、Ｍｏ、Ｇｅ、Ｓｂ、Ｓｎ、Ｂｉ、Ｎｉ他を添
加でき、本発明はいかなるＲ−ＴＭ−Ｂ系永久磁石にも
適用できる。また、その製造方法は焼結法、溶湯急冷
法、あるいはそれらの変形法のいずれの方法でもよい。
金属の被覆方法としては、電気めっき法、無電解めっき
法、蒸着法のいずれかの方法により行う。それぞれの金
属に応じて最適な被覆方法を用いればよく、金属被覆層
の厚さは各層２〜２０μｍ、総厚１０〜２５μｍが好ま
しい。各層の厚さがおよび総厚がそれぞれ２μｍ未満お
よび１０未満μｍだと十分な耐食性を得るのが困難であ
り、また各層の厚さおよび総厚がそれぞれ２０μｍおよ
び２５μｍを越えると磁石として機能しない部分が多く
なり好ましくないからである。なお、本発明の金属被覆
層は少なくとも３種、つまり３層あればよく、本発明の
趣旨に従って４層以上の積層としてもよいことは言うま
でもない。When the electrochemically noble metal coating layer is provided as the lower layer and the base metal coating layer is provided as the upper layer on the surface of the material, the base upper layer is anodized due to the relationship between the corroded battery rows of both, and the anode effect is obtained. Is generated, the noble lower layer is cathodically protected. In other words, it is considered that the above-mentioned anticorrosion effect becomes stronger for the three different metal coating layers that are laminated electrochemically in a noble order, the permeation of moisture into the intermediate layer is prevented, and at the same time the base is protected. Be done.
The present invention improves the corrosion resistance of the R-TM-B based permanent magnet due to the anticorrosion effect. Needless to say, the metal coating layer of the present invention may be at least three types, that is, three layers, and may be a laminate of four or more layers in accordance with the gist of the present invention. In the present invention, an element that partially replaces TM such as Fe, Co, and Ni is, depending on the purpose of addition,
Ga, Al, Ti, V, Cr, Mn, Zr, Hf, N
b, Ta, Mo, Ge, Sb, Sn, Bi, Ni, etc. can be added, and the present invention can be applied to any R-TM-B type permanent magnet. Further, the manufacturing method thereof may be a sintering method, a molten metal quenching method, or a modification thereof.
As a method for coating the metal, any one of an electroplating method, an electroless plating method, and a vapor deposition method is used. An optimal coating method may be used depending on each metal, and the thickness of the metal coating layer is preferably 2 to 20 μm for each layer and 10 to 25 μm in total thickness. If the thickness and total thickness of each layer are less than 2 μm and less than 10 μm, respectively, it is difficult to obtain sufficient corrosion resistance, and if the thickness and total thickness of each layer exceed 20 μm and 25 μm, respectively, a portion that does not function as a magnet This is because it is not preferable because it increases the number. Needless to say, the metal coating layer of the present invention may be at least three types, that is, three layers, and may be a laminate of four or more layers in accordance with the gist of the present invention.
【０００７】[0007]
【実施例】ＮＤ（Ｆｅ0.7Ｃｏ0.2Ｂ0.07Ｇａ0.03）6.5
なる組成の合金をアーク溶解にて作製し、得られたイン
ゴットをスタンプミル及びディスクミルで粗粉砕した。
その後、Ｎ2ガスを粉砕媒体としてジェットミルで微粉
砕を行い、粉砕粒度３．５μｍｌ（ＦＳＳＳ）の微粉砕
を得た。得られた原料粉を１５ＫＯｅの磁場中で横磁場
成形した。成形圧力は２Ｔｏｎ／ｃｍ2であった。本成
形体を真空中で１０９０℃×２時間焼結した。焼結体を
１８×１０×６ｍｍの寸法に切り出し、次いで９００℃
のアルゴン雰囲気中に２時間加熱保持した後に急冷し温
度を６００℃に保持したアルゴンの雰囲気中で１時間保
持した。こうして得られた試料について、表１に示した
条件で金属被覆層を被覆し、これを試験片とした。EXAMPLE ND (Fe 0.7 Co 0.2 B 0.07 Ga 0.03 ) 6.5
An alloy having the following composition was produced by arc melting, and the obtained ingot was roughly crushed by a stamp mill and a disc mill.
Then, fine pulverization was carried out by a jet mill using N 2 gas as a pulverizing medium to obtain fine pulverization having a pulverized particle size of 3.5 μml (FSSS). The obtained raw material powder was subjected to transverse magnetic field molding in a magnetic field of 15 KOe. The molding pressure was 2 Ton / cm 2 . The compact was sintered in vacuum at 1090 ° C for 2 hours. Cut the sintered body into a size of 18 × 10 × 6 mm, then 900 ° C.
After heating and holding in the argon atmosphere for 2 hours, it was rapidly cooled and held for 1 hour in the argon atmosphere in which the temperature was kept at 600 ° C. The sample thus obtained was coated with a metal coating layer under the conditions shown in Table 1 and used as a test piece.
【０００８】[0008]
【表１】 表１に示した試料に関して、８０℃９０％ＲＨでの１０
００時間の耐食試験及び３５℃ ５％ＮａＣｌでの２０
０時間の塩水噴霧試験を行った。結果を表２に示す。[Table 1] For the samples shown in Table 1, 10 at 80 ° C. 90% RH
00 hour corrosion resistance test and 20 at 35 ° C 5% NaCl
A zero hour salt spray test was conducted. The results are shown in Table 2.
【０００９】[0009]
【表２】 表２において、耐食試験結果は試料の外観変化を、塩水
噴霧試験結果は赤錆発生時間を示したものである。表２
より、本発明による永久磁石は、従来の磁石と比較し
て、耐食性を著しく向上し得ることがわかる。[Table 2] In Table 2, the corrosion resistance test results show the appearance change of the samples, and the salt spray test results show the red rust generation time. Table 2
Therefore, it can be seen that the permanent magnet according to the present invention can significantly improve the corrosion resistance as compared with the conventional magnet.
【００１０】[0010]
【発明の効果】本発明により、希土類と鉄を主体とした
磁石において、従来の金属めっきでは不十分であった耐
食性の顕著な向上が図られた。According to the present invention, in the magnet mainly composed of rare earth and iron, the corrosion resistance, which was insufficient by the conventional metal plating, was remarkably improved.
Claims (2)
元素の１種又は２種以上の組み合わせ）５〜４０％、Ｔ
Ｍ（ここでＴＭは、Ｆｅ、Ｃｏを中心とする遷移金属で
あって、一部を他の金属元素又は非金属元素で置換して
よい）５０〜９０％、Ｂ（硼素）０．２〜８％からなる
Ｒ−ＴＭ−Ｂ系永久磁石において、該永久磁石の表面
に、電気化学的に貴な順に積層被覆された３種の異なる
金属被覆層を有することを特徴とする耐食性を改善した
Ｒ−ＴＭ−Ｂ系永久磁石。1. A weight ratio of R (here, one or a combination of two or more rare earth elements including Y) 5 to 40%, T
M (here, TM is a transition metal mainly composed of Fe and Co, and may be partially replaced with other metal element or non-metal element) 50 to 90%, B (boron) 0.2 to In an 8% R-TM-B based permanent magnet, the surface of the permanent magnet has three different metal coating layers laminated and coated electrochemically in a noble order to improve corrosion resistance. R-TM-B system permanent magnet.
ＣｕあるいはＮｉのいずれかの金属被覆層であり、中間
層がＮｉあるいはＮｉ−Ｓのいずれかの金属被覆層であ
り、最上層がＮｉ−Ｓ、Ｎｉ−Ｐ、Ｓｎ、Ｓｎ−Ｐｂ、
Ｃｒ、Ｚｎ、Ａｌから選ばれた１種の金属被覆層である
請求項１に記載の耐食性を改善したＲ−ＴＭ−Ｂ系永久
磁石。2. The three different types of metal coating layers, the bottom layer is a metal coating layer of Cu or Ni, the intermediate layer is a metal coating layer of Ni or Ni-S, the uppermost layer Is Ni-S, Ni-P, Sn, Sn-Pb,
The R-TM-B system permanent magnet with improved corrosion resistance according to claim 1, which is one kind of metal coating layer selected from Cr, Zn, and Al.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4136695A JPH05335123A (en) | 1992-05-28 | 1992-05-28 | Corrosion-proof property improved r-tm-b permanent magnet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4136695A JPH05335123A (en) | 1992-05-28 | 1992-05-28 | Corrosion-proof property improved r-tm-b permanent magnet |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH05335123A true JPH05335123A (en) | 1993-12-17 |
Family
ID=15181316
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4136695A Pending JPH05335123A (en) | 1992-05-28 | 1992-05-28 | Corrosion-proof property improved r-tm-b permanent magnet |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH05335123A (en) |
-
1992
- 1992-05-28 JP JP4136695A patent/JPH05335123A/en active Pending
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