JPH0582322A - R-tm-b series permanent magnet having improved corrosion resistance and film thickness uniformity - Google Patents
R-tm-b series permanent magnet having improved corrosion resistance and film thickness uniformityInfo
- Publication number
- JPH0582322A JPH0582322A JP3239463A JP23946391A JPH0582322A JP H0582322 A JPH0582322 A JP H0582322A JP 3239463 A JP3239463 A JP 3239463A JP 23946391 A JP23946391 A JP 23946391A JP H0582322 A JPH0582322 A JP H0582322A
- Authority
- JP
- Japan
- Prior art keywords
- permanent magnet
- corrosion resistance
- film thickness
- plating
- thickness uniformity
- 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、磁石体において無電解によるＮｉ−Ｐめっ
き層を設けることにより耐食性及び膜厚均一性を著しく
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 magnet body provided with an electroless Ni-P plating layer to remarkably improve corrosion resistance and film thickness uniformity. ..
【０００２】[0002]
【従来の技術】電気・電子機器の高性能・小型化に伴な
って、その一部品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−
ＴＭ−Ｂ系永久磁石が台頭してきた（特開昭５９−４６
００８号）。ここにＲはＹを含む希土類元素の１種又は
２種以上の組合わせであり、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、永久磁石体表面に耐
酸化性の被覆層を設ける手段がとられきた。被覆層の種
類としては、電解Ｎｉめっき、耐酸化性樹脂、Ａｌイオ
ンプレーティング等が提案されており、とりわけ電解Ｎ
ｉ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）。電解Ｎｉ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。2. Description of the Related Art As electric and electronic devices have become more sophisticated and smaller in size, the same requirements have been increased for a permanent magnet, which is one of the components. That is, the strongest permanent magnet before was a rare earth / cobalt (R-Co) system, but in recent years, a stronger R-co
TM-B system permanent magnets have emerged (Japanese Patent Laid-Open No. 59-46).
No. 008). Here, R is one or a combination of two or more rare earth elements including Y, TM is a transition metal center such as Fe or Co, and a part thereof is replaced with another metal element or non-metal element, B is boron. However, R-TM-B
The system 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 body. As the type of coating layer, electrolytic Ni plating, oxidation resistant resin, Al ion plating, etc. have been proposed.
The i-plating has been attracting attention because it improves the corrosion resistance of the R-TM-B type permanent magnet with a simple treatment (Japanese Patent Laid-Open No. 60-
54406). Electrolytic Ni plating has the advantage that the surface coating layer is superior in mechanical strength to the oxidation resistant resin, and that the coating layer itself has almost no hygroscopicity.
【０００３】[0003]
【発明が解決しようとする課題】しかしながら、電解Ｎ
ｉめっきによる手法は、めっき電流が磁石体のコーナ部
などの周辺部に集中しやすいことから膜厚が厚くなり、
内穴及び内径部には電流が流れにくいことから膜厚が薄
くなるという傾向を有していた。そのため電解Ｎｉめっ
きのままでは十分な膜厚均一化を図ることができず、特
に円筒状の様な異形品に関しては内径部にＮｉめっき層
をほとんど被覆することができず耐食性の面で問題とな
っていた。そこで本発明の目的は、信頼性の高い耐食性
及び膜厚均一性を改善したＲ−ＴＭ−Ｂ系永久磁石を提
供することにある。However, the electrolytic N
In the method using i-plating, the plating current tends to concentrate on the peripheral portion such as the corner of the magnet body, resulting in a thicker film,
Since the current does not easily flow in the inner hole and the inner diameter portion, the film thickness tends to be thin. Therefore, it is not possible to achieve a sufficient film thickness homogeneity with electrolytic Ni plating, and in particular for irregularly shaped products such as cylinders, the Ni plating layer can hardly be coated on the inner diameter portion, which poses a problem in terms of corrosion resistance. Was becoming. Therefore, an object of the present invention is to provide an R-TM-B system permanent magnet with highly reliable corrosion resistance and improved film thickness uniformity.
【０００４】[0004]
【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Ｙを含む希土類元素の１種又は２種以上組合わ
せ）５〜４０％，ＴＭ（ここでＴＭはＦｅを主体とする
遷移金属）５０〜９０％，Ｂ（硼素）０．２〜８％から
なるＲ−ＴＭ−Ｂ系永久磁石の表面に、電解によるＮｉ
ストライクめっき層を設け、その上に無電解によるＮｉ
−Ｐめっき層を設けることを特徴とする耐食性及び膜厚
均一性を改善したＲ−ＴＭ−Ｂ系永久磁石及びその製造
方法である。Ｎｉイオンから還元剤によってＮｉ金属を
析出させることを原理とし、析出した皮膜の非晶質構造
により高耐食性を示す無電解Ｎｉ−Ｐめっきは、外部か
ら電流を流して行なう電解Ｎｉめっきと比較し膜厚精度
が良好であるという長所を有している。そのため、電気
めっきでは膜厚均一化が困難だった円筒状の様な異形品
に関しても、内外径に関係なく均一にめっきを被覆でき
るものと考えられる。本発明は、前記した様に無電解に
よるＮｉ−Ｐめっきを施すことにより、Ｒ−ＴＭ−Ｂ系
永久磁石の耐食性及び膜厚均一性を向上するものであ
る。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，Ａ
ｌ，Ｔｉ，Ｖ，Ｃｒ，Ｍｎ，Ｚｒ，Ｈｆ，Ｎｂ，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。めっき前処理に関
しては、加工変質層の除去及びめっき前活性化を図る上
で、酸性溶液を用いるのが良い。硫酸や塩酸等の強酸が
めっき前活性化にとって有効であるが、めっき前処理の
材質への影響を極力避けるためには、２〜１０ｖｏｌ％
の硝酸による第１エッチング、その後過酸化水素５〜１
０ｖｏｌ％、酢酸１０〜３０ｖｏｌ％の混酸による第２
エッチングが最も望ましい。次いで、電解によるＮｉス
トライクめっき処理を行なう。無電解によるＮｉ−Ｐめ
っき処理を行なう前に、必ず電解によるＮｉストライク
めっき処理を行なう。これはＲ−ＴＭ−Ｂ系永久磁石を
無電解Ｎｉ−Ｐめっき液に直接浸漬すると、めっき金属
が磁石体表面に析出する以前に磁石材料がめっき液によ
り腐食溶解してしまい、良好なめっき皮膜が形成されな
くなるためである。そのため、電解によるＮｉ−Ｐスト
ライク層を設けることにより触媒活性化を行なうこと
が、良好なめっき皮膜を形成させる上でより望ましい。
電解Ｎｉめっきの種類としては、ワット浴、スルファミ
ン酸浴、アンモン浴のいずれでも良い。また電流密度は
１〜１０Ａ／ｄｍ2が良く、Ｎｉめっき層の厚さは０．
５〜５μｍが好ましい。次いで、電解によるＮｉストラ
イクめっき処理後の水洗の後に、電解によるＮｉ−Ｐめ
っき処理を行なう。無電解Ｎｉ−Ｐめっき液の組成とし
ては、金属塩として塩化ニッケル、硫酸ニッケル、次亜
リン酸ニッケルのうち少なくとも一種を１００ｇ／ｌ以
下含有し、還元剤として次亜リン酸ナトリウムを１００
ｇ／ｌ以下、ｐＨ調整剤とし水酸化ナトリウム、水酸化
アンモニウム等の塩基性化合物、無機酸、有機酸のうち
少なくとも一種を１５０ｇ／ｌ以下含むものが好まし
い。なおこの電解液には緩衝剤としてクエン酸ナトリウ
ム、酢酸ナトリウム等のオキシカルボン酸、あるいは硼
素、炭酸等の無機酸のうち少なくとも１種を１５０ｇ／
ｌ以下、錯化剤としてクエン酸ナトリウム、酢酸ナトリ
ウム、水酸化アンモニウム、エチレングリコール、さら
には有機酸（酢酸、グリコール酸、クエン酸、酒石酸
等）のアルカリ塩、チオグリコール酸、アンモニア、ト
リエタノールアミン、エチレンジアミン、グリシン、ピ
リジンの少なくとも１種を１００ｇ／ｌ含むほか促進
剤、安定剤として１０ｇ／ｌ以下の硫化物、塩化物、フ
ッ化物、界面活性剤をそれぞれ含有することができ、こ
の水溶液はｐＨ３〜１３の範囲で用い、メッキ時の浴温
は２０〜１００℃の範囲である。析出しためっき皮膜は
ＮｉとＰを主成分とし、ＰがＮｉ中に可飽和に固溶した
非晶質相、あるいはＮｉとＮｉ3Ｐ等のリン化ニッケル
相との微細混合相から成るものであり、耐食性の面でめ
っきの厚さは１０〜２０μｍが好ましく、この層中のＰ
の割合は１〜１４ｗｔ％が好ましい。Ｎｉのみの無電解
めっき皮膜では、ピンホールが多いため耐食性に劣り使
用できない。またＮｉ−ＢあるいはＮｉ−Ｎ等の無電解
めっき皮膜もピンホールが多く十分な耐食性が得られな
いため、ＢあるいはＮを主成分とする還元剤を含む無電
解めっき液は使用してはならない。In the present invention, the weight ratio of R (where R is one or a combination of two or more rare earth elements including Y) is 5 to 40%, TM (here, TM is mainly Fe). On the surface of the R-TM-B system permanent magnet composed of 50 to 90% of the transition metal) and 0.2 to 8% of B (boron).
Strike plating layer is provided, and electroless Ni is formed on it.
An R-TM-B based permanent magnet with improved corrosion resistance and film thickness uniformity, characterized by providing a -P plating layer, and a method for producing the same. In principle, electroless Ni-P plating, which has high corrosion resistance due to the amorphous structure of the deposited film, is used as a principle in which Ni metal is deposited from Ni ions with a reducing agent. It has the advantage of good film thickness accuracy. Therefore, it is considered that even in the case of a deformed product such as a cylindrical shape, for which it was difficult to make the film thickness uniform by electroplating, the plating can be uniformly coated regardless of the inner and outer diameters. The present invention improves the corrosion resistance and film thickness uniformity of the R-TM-B based permanent magnet by performing electroless Ni-P plating as described above. In the present invention, elements such as Fe, Co, and Ni that partially substitute for TM are Ga, A, and the like depending on the purpose of addition.
l, Ti, V, Cr, Mn, Zr, Hf, Nb, Ta,
Mo, Ge, Sb, Sn, Bi, Ni, etc. can be added, and the present invention can be applied to any R-TM-B type magnet. Further, the manufacturing method thereof may be a sintering method, a molten metal quenching method, or a modification thereof. Regarding the pre-plating treatment, it is preferable to use an acidic solution in order to remove the work-affected layer and activate the pre-plating. Strong acids such as sulfuric acid and hydrochloric acid are effective for pre-plating activation, but in order to avoid the influence of pre-plating treatment on the material as much as possible, 2-10 vol%
Etching with nitric acid, then hydrogen peroxide 5-1
2nd by mixed acid of 0 vol% and acetic acid 10-30 vol%
Etching is most desirable. Then, Ni strike plating treatment by electrolysis is performed. Before performing electroless Ni-P plating, electrolytic Ni strike plating is always performed. This is because when the R-TM-B system permanent magnet is directly immersed in the electroless Ni-P plating solution, the magnet material is corroded and dissolved by the plating solution before the plating metal is deposited on the surface of the magnet body, resulting in a good plating film. Is not formed. Therefore, it is more desirable to activate the catalyst by providing a Ni-P strike layer by electrolysis in order to form a good plating film.
The type of electrolytic Ni plating may be a Watt bath, a sulfamic acid bath, or an ammonium bath. The current density is preferably 1 to 10 A / dm 2 , and the thickness of the Ni plating layer is 0.
It is preferably 5 to 5 μm. Next, after washing with water after electrolytic Ni strike plating, electrolytic Ni-P plating is performed. The composition of the electroless Ni-P plating solution contains 100 g / l or less of at least one of nickel chloride, nickel sulfate, and nickel hypophosphite as a metal salt, and 100% sodium hypophosphite as a reducing agent.
It is preferably g / l or less, and a pH adjusting agent containing at least 150 g / l or less of a basic compound such as sodium hydroxide and ammonium hydroxide, an inorganic acid and an organic acid. The electrolytic solution contains at least one oxycarboxylic acid such as sodium citrate and sodium acetate as a buffering agent, or at least one inorganic acid such as boron and carbonic acid at 150 g /
1 or less, sodium citrate, sodium acetate, ammonium hydroxide, ethylene glycol as a complexing agent, and an alkali salt of an organic acid (acetic acid, glycolic acid, citric acid, tartaric acid, etc.), thioglycolic acid, ammonia, triethanolamine In addition to containing 100 g / l of at least one of ethylenediamine, glycine and pyridine, it is possible to contain a sulfide, chloride, fluoride and surfactant of 10 g / l or less as an accelerator and a stabilizer, respectively. It is used in the pH range of 3 to 13, and the bath temperature during plating is in the range of 20 to 100 ° C. The deposited plating film is mainly composed of Ni and P, and is composed of an amorphous phase in which P is saturable as a solid solution in Ni or a fine mixed phase of Ni and a nickel phosphide phase such as Ni 3 P. The thickness of the plating is preferably 10 to 20 μm from the viewpoint of corrosion resistance.
Is preferably 1 to 14 wt%. An electroless plating film containing only Ni has many pinholes and is inferior in corrosion resistance and cannot be used. In addition, the electroless plating film such as Ni-B or Ni-N also has many pinholes and sufficient corrosion resistance cannot be obtained. Therefore, an electroless plating solution containing a reducing agent containing B or N as a main component should not be used. ..
【０００５】[0005]
【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。
粉砕媒体としてはＮ2ガスを用いジェットミルで微粉砕
を行なう粉砕粒度３．５μｍ（ＦＳＳＳ）の微粉砕を得
た。得られた原料粉を１５ｋＯｅの磁場中で配向し、２
トン／ｃｍ2の圧力で円筒体に成形した。本成形体を真
空中で１０９０℃×２時間焼結した。焼結体を外径２０
×内径１６×高さ１０ｍｍ寸法の円筒体に切り出し次い
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、めっ
き前処理として５ｖｏｌ％の硝酸による第１エッチン
グ、その後過酸化水素１０ｖｏｌ％、酢酸２５ｖｏｌ％
の混酸による第２エッチングを行なった。その後、表１
に示す作業条件で、円筒体外径部のめっき層の厚みが表
１に示した値となる様に各種表面処理を施した。EXAMPLES 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.
N 2 gas was used as the grinding medium to carry out fine grinding with a jet mill to obtain fine grinding having a grinding particle size of 3.5 μm (FSSS). The obtained raw material powder was oriented in a magnetic field of 15 kOe, and 2
It was molded into a cylinder at a pressure of ton / cm 2 . The compact was sintered in vacuum at 1090 ° C for 2 hours. Outer diameter of the sintered body is 20
It was cut out into a cylinder having dimensions of inner diameter 16 × height 10 mm and then heated and held in an argon atmosphere at 900 ° C. for 2 hours and then rapidly cooled and held in an argon atmosphere in which the temperature was kept at 600 ° C. for 1 hour. For the sample thus obtained, the first etching with 5 vol% nitric acid was performed as a pretreatment for plating, followed by 10 vol% hydrogen peroxide and 25 vol% acetic acid.
The second etching was performed using the mixed acid of. Then Table 1
Under the working conditions shown in Table 1, various surface treatments were performed so that the thickness of the plating layer on the outer diameter portion of the cylindrical body had the values shown in Table 1.
【０００６】[0006]
【表１】 [Table 1]
【０００７】表１に示した試料に関して、円筒体内径部
のめっき層の厚みを測定し、１１９．６℃１００％ＲＨ
２気圧での１００時間の耐食試験および８０℃９０％
ＲＨでの５００時間の耐湿試験を行なった。結果を表２
に示す。With respect to the samples shown in Table 1, the thickness of the plating layer on the inner diameter of the cylinder was measured and was 119.6 ° C. and 100% RH.
Corrosion resistance test at 2 atm for 100 hours and 90% at 80 ℃
A humidity resistance test was carried out at RH for 500 hours. The results are shown in Table 2.
Shown in.
【０００８】[0008]
【表２】 [Table 2]
【０００９】表２において、耐食試験結果及び耐湿試験
結果は試料の外観変化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
性及び膜厚均一性を著しく向上し得ることがわかる。In Table 2, the corrosion resistance test results and the humidity resistance test results show changes in the appearance of the samples. From Table 2,
It can be seen that the permanent magnet according to the present invention can significantly improve the corrosion resistance and the film thickness uniformity 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、従来のめっきでは不十分であった耐食性
及び膜厚均一性の顕著な向上が図られた。According to the present invention, in a magnet mainly composed of rare earth and iron, the corrosion resistance and the film thickness uniformity, which were insufficient by the conventional plating, were remarkably improved.
Claims (2)
類元素の１種又は２種以上組合わせ）５〜４０％，ＴＭ
（ここでＴＭはＦｅを主体とする遷移金属）５０〜９０
％，Ｂ（硼素）０．２〜８％からなるＲ−ＴＭ−Ｂ系永
久磁石の表面に電解Ｎｉストライクめっき層と、その上
に無電解Ｎｉ−Ｐめっき層からなる二重層を有する耐食
性及び膜厚均一性を改善したＲ−ＴＭ−Ｂ系永久磁石。1. A weight ratio of R (where R is one or a combination of two or more rare earth elements including Y) 5 to 40%, TM
(Here, TM is a transition metal mainly composed of Fe) 50 to 90
%, B (boron) 0.2 to 8% R-TM-B based permanent magnet surface has an electrolytic Ni strike plating layer and a double layer consisting of an electroless Ni-P plating layer on the corrosion resistance and R-TM-B system permanent magnet with improved film thickness uniformity.
類元素の１種又は２種以上の組合せ）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もよい。）５
０〜９０％，Ｂ（硼素）０．２〜８％からなるＲ−ＴＭ
−Ｂ系永久磁石の表面にＮｉストライクめっき層を有
し、その上にＮｉ−Ｐめっき層からなる二重層を有する
耐食性及び膜厚均一性を改善したＲ−ＴＭ−Ｂ系永久磁
石。2. A weight ratio of R (where R is one or a combination of two or more rare earth elements including Y) 5 to 40%, TM
(Here, TM is a transition metal mainly composed of Fe, and a part thereof may be replaced with another metal element or non-metal element.) 5
R-TM consisting of 0 to 90% and B (boron) 0.2 to 8%
An R-TM-B system permanent magnet having a Ni strike plating layer on the surface of a -B system permanent magnet and a double layer formed of a Ni-P plating layer on the Ni strike plating layer and having improved corrosion resistance and film thickness uniformity.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3239463A JPH0582322A (en) | 1991-09-19 | 1991-09-19 | R-tm-b series permanent magnet having improved corrosion resistance and film thickness uniformity |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3239463A JPH0582322A (en) | 1991-09-19 | 1991-09-19 | R-tm-b series permanent magnet having improved corrosion resistance and film thickness uniformity |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0582322A true JPH0582322A (en) | 1993-04-02 |
Family
ID=17045137
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3239463A Pending JPH0582322A (en) | 1991-09-19 | 1991-09-19 | R-tm-b series permanent magnet having improved corrosion resistance and film thickness uniformity |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0582322A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008010726A (en) * | 2006-06-30 | 2008-01-17 | Daido Electronics Co Ltd | Rare earth bond magnet |
-
1991
- 1991-09-19 JP JP3239463A patent/JPH0582322A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008010726A (en) * | 2006-06-30 | 2008-01-17 | Daido Electronics Co Ltd | Rare earth bond magnet |
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