JPH08325677A - Corrosion resistant sintered magnetic alloy - Google Patents
Corrosion resistant sintered magnetic alloyInfo
- Publication number
- JPH08325677A JPH08325677A JP7133532A JP13353295A JPH08325677A JP H08325677 A JPH08325677 A JP H08325677A JP 7133532 A JP7133532 A JP 7133532A JP 13353295 A JP13353295 A JP 13353295A JP H08325677 A JPH08325677 A JP H08325677A
- Authority
- JP
- Japan
- Prior art keywords
- plating film
- magnetic alloy
- corrosion resistance
- film
- plating
- 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、磁性合金であって、そ
の表面に形成したＮｉめっき膜の組成を制御することに
より焼結磁性合金の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 a magnetic alloy in which the corrosion resistance of a sintered magnetic alloy is remarkably improved by controlling the composition of a Ni plating film formed on the surface of the magnetic alloy.
【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−Ｔ
Ｍ−Ｂ系磁性合金が台頭してきた（特開昭５９−４６０
０８号）。ここにＲはＹを含む希土類元素の１種または
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または非金属元
素で置換したもの、Ｂはホウ素である。前記、磁性合金
は粉末冶金的手法により焼結法で製造されるが、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、電気Ｎｉ
めっき、耐酸化性樹脂、Ａｌイオンプレ−ティング等が
提案されており、とりわけ電気Ｎｉ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）。電気
Ｎｉめっき膜は、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 With the high performance and miniaturization of electric and electronic devices, the same demands have been placed on the permanent magnet, which is one of the components. In other words, the strongest permanent magnet before was the rare earth-cobalt (R-Co) system, but in recent years, the stronger RT
The emergence of MB magnetic alloys (JP-A-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, and a part thereof is replaced with another metal element or non-metal element, B Is boron. Although the magnetic alloy is manufactured by a powder metallurgical method by a sintering method, it has a problem that it is extremely rusty. Therefore, measures have been taken to provide an oxidation resistant coating layer on the surface of the permanent magnet in order to improve the corrosion resistance. The type of coating layer is electric Ni
Plating, oxidation resistant resin, Al ion plating, and the like have been proposed, and in particular, electric Ni plating has attracted attention because it improves the corrosion resistance of the R-TM-B type permanent magnet by a simple treatment (Japanese Patent Laid-Open No. Sho-06-1999). 60-54406). The electroplated Ni film 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.
【０００３】[0003]
【発明が解決しようとする課題】耐食性磁性合金上に電
気Ｎｉめっき膜を形成する浴組成としてはワット浴が一
般的である。このワット浴単独では緻密なＮｉめっき膜
が得られないので、膜の緻密化の手段としてＮｉめっき
膜中にイオウ（Ｓ）を含有させて膜組織を緻密化する方
法が一般的に行われる。しかしながら、Ｎｉ・Ｓめっき
膜は、Ｎｉ膜よりも電極電位が卑となり電気化学的にめ
っき膜自身の耐食性が低下するため、Ｎｉ・Ｓ合金めっ
き膜の方がＮｉめっき膜より耐食性が悪くなるという問
題点があった。本発明の目的は、前記従来問題点を解決
し、焼結磁性合金上に形成したＮｉめっき膜の組成を制
御することにより信頼性の高い耐食性を有する磁性合金
を提供することである。A watt bath is generally used as a bath composition for forming an electroplated Ni film on a corrosion-resistant magnetic alloy. Since a dense Ni-plated film cannot be obtained by this Watt bath alone, a method of densifying the film structure by incorporating sulfur (S) into the Ni-plated film is generally performed as a means for densifying the film. However, the Ni / S plated film has a lower electrode potential than the Ni film and electrochemically lowers the corrosion resistance of the plated film itself. Therefore, the Ni / S alloy plated film is inferior in corrosion resistance to the Ni plated film. There was a problem. An object of the present invention is to solve the above-mentioned conventional problems and provide a magnetic alloy having a highly reliable corrosion resistance by controlling the composition of a Ni plating film formed on a sintered magnetic alloy.
【０００４】[0004]
【課題を解決するための手段】上記従来の問題点を解決
するために、本発明では、重量比でＲ（ここでＲは、Ｙ
を含む希土類元素の１種または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、一部を他の金属または非金属元素で置
換してよい）５０〜９０％、Ｂ（ホウ素）０．２〜８％
からなる焼結磁性合金の表面にＮｉめっき膜を形成した
耐食性焼結磁性合金において、該Ｎｉめっき膜中のカー
ボン含有量が５０〜８００ｐｐｍであり、かつイオウ含
有量が１００〜８００ｐｐｍである、という技術的手段
を採用した。本発明において、Ｆｅ、Ｃｏ、Ｎｉ等のＴ
Ｍの一部を置換する元素は、その添加目的に応じて、Ｇ
ａ、Ａｌ、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系焼結磁性合金にも
適用できる。In order to solve the above-mentioned conventional problems, in the present invention, the weight ratio R (where R is Y
One or a combination of two or more rare earth elements including)
5 to 40%, TM (here, TM is a transition metal mainly composed of Fe and may be partially replaced with other metal or non-metal element) 50 to 90%, B (boron) 0. 2-8%
In a corrosion-resistant sintered magnetic alloy having a Ni plated film formed on the surface of a sintered magnetic alloy consisting of, the carbon content in the Ni plated film is 50 to 800 ppm, and the sulfur content is 100 to 800 ppm. Adopted technical means. In the present invention, T such as Fe, Co, or Ni is used.
The element substituting a part of M is G depending on the purpose of addition.
a, Al, Ti, V, Cr, Mn, Zr, Hf, Nb,
Ta, Mo, Ge, Sb, Sn, Bi, Ni and others can be added, and the present invention can be applied to any R-TM-B based sintered magnetic alloy.
【０００５】[0005]
【作用】カーボンとイオウをＮｉめっき膜中に複合微量
添加することにより、Ｎｉめっき膜の電極電位が卑にな
らずにめっき膜質の緻密化を達成することができ、Ｎｉ
めっき膜の耐食性を大幅に向上させることができる。イ
オウ含有量が１００ｐｐｍ未満ではめっき膜が緻密化せ
ず、８００ｐｐｍを越えるとめっき膜が脆くなりめっき
膜の密着性が低下する。また、カーボン含有量が５０ｐ
ｐｍ未満では耐食性向上の効果が得られず、８００ｐｐ
ｍを越えるとめっき膜にピットが発生し易くなり、めっ
き膜質が低下する。[Function] By adding a very small amount of carbon and sulfur to the Ni plating film, it is possible to achieve densification of the plating film quality without making the electrode potential of the Ni plating film base.
The corrosion resistance of the plated film can be greatly improved. If the sulfur content is less than 100 ppm, the plating film will not be densified, and if it exceeds 800 ppm, the plating film will become brittle and the adhesion of the plating film will decrease. Also, the carbon content is 50p
If it is less than pm, the effect of improving corrosion resistance cannot be obtained, and 800 pp
If it exceeds m, pits are likely to occur in the plating film, and the quality of the plating film deteriorates.
【０００６】[0006]
【実施例】以下、本発明の効果を実施例により具体的に
説明する。Ｎｄ（Ｆｅ0.7Ｃｏ0.2Ｂ0.07Ｇａ0.03）6.5
なる組成の合金をア−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３．５μｍの微粉砕粉を得た。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。EXAMPLES The effects of the present invention will be specifically described below with reference to examples. Nd (Fe0.7Co0.2B0.07Ga0.03) 6.5
An alloy having the following composition was prepared by arc melting, and the obtained ingot was roughly crushed by a stamp mill and a disc mill.
Then, N2 gas was used as a grinding medium to perform fine pulverization with a jet mill to obtain fine pulverized powder having a pulverized particle size of 3.5 μm. 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. 18 x 10 x sintered body
Cut out to a size of 6 mm, then heat and hold in an argon atmosphere at 900 ° C for 2 hours and then rapidly cool to 600 ° C.
It was held for 1 hour in the atmosphere of argon held in.
【０００７】こうして得られた試料について、めっき前
処理として試料表面の加工歪み層及び酸化膜除去の目的
で５ｖｏｌ％の硝酸によるエッチングを行い、その後ワ
ット浴にてＮｉめっき膜を形成した。Ｎｉめっき膜中に
イオウを微量含有する手段としてサッカリンをワット浴
中に２ｇ／ｌ添加し、めっき時の電流密度を調節するこ
とでイオウ含有量を調整した。また、カーボンをめっき
膜中に微量添加する方法としてアノードにカーボナイズ
ドニッケルを用い、そのカーボン含有量を調整すること
により、Ｎｉめっき膜中のカーボン量を調整した。Ｎｉ
めっき膜を１５μｍ形成し、これを試験片とした。めっ
き膜中のカーボン量は不活性ガス加熱溶解法により定量
し、イオウ量はケイ光Ｘ線により分析した。めっき膜の
密着性試験は引っ張り試験機（セバスチャン１）によ
り、また、塩水噴霧試験は３５℃、５％食塩水で１００
時間行った。結果を表１に示す。The sample thus obtained was etched with 5 vol% nitric acid for the purpose of removing the work strain layer and oxide film on the sample surface as a pretreatment for plating, and then a Ni plating film was formed in a Watts bath. As a means for containing a trace amount of sulfur in the Ni plating film, 2 g / l of saccharin was added to the Watt bath, and the sulfur content was adjusted by adjusting the current density during plating. Further, as a method of adding a small amount of carbon to the plated film, carbonized nickel was used for the anode, and the carbon content was adjusted to adjust the carbon amount in the Ni plated film. Ni
A plated film having a thickness of 15 μm was formed and used as a test piece. The amount of carbon in the plating film was quantified by an inert gas heating dissolution method, and the amount of sulfur was analyzed by fluorescent X-ray. The adhesion test of the plating film was conducted by a tensile tester (Sebastian 1), and the salt spray test was conducted at 35 ° C. and 5% saline solution at 100.
I went on time. The results are shown in Table 1.
【０００８】[0008]
【表１】 カーボン量 イオウ量 密着性試験 塩水噴霧試験 (ppm) (ppm) (kgf/cm2) 35℃5%NaCl100h n=20 n=20 実施例１ ５０ １８０ ３９０ 発錆なし 実施例２ １８０ ４５０ ４１０ 発錆なし 実施例３ ６５０ ７５０ ３８０ 発錆なし 比較例１ ３０ ３００ ３８０ ６ヶ発錆 比較例２ １００ ７５ ３６０ １０ヶ発錆 比較例３ ９００ ７００ ３３０ １６ヶ発錆 比較例４ ４５０ ９５０ ２３０ ２ヶ発錆 [Table 1] Carbon amount Sulfur amount Adhesion test Salt spray test (ppm) (ppm) (kgf / cm2) 35 ° C 5% NaCl100h n = 20 n = 20 Example 1 50 180 390 No rust Example 2 180 450 410 No rusting Example 3 650 750 380 No rusting Comparative Example 1 30 300 380 6 rusting Comparative Example 2 100 75 360 360 10 rusting Comparative Example 3 900 700 330 16 16 rusting Comparative Example 4 450 950 230 2 Rusting
【０００９】表１より、Ｒ−ＴＭ−Ｂ系焼結磁性合金に
おいて、従来の電気Ｎｉめっきでは不充分であったＮｉ
めっき膜の耐食性が著しく向上したことがわかる。ま
た、Ｎｉめっき膜中に含有するカーボン量が５０ｐｐｍ
未満では耐食性の向上の効果が得られず、８００ｐｐｍ
を越えるとＮｉめっき膜にピットが発生し易くなり耐食
性が劣化する。一方、Ｎｉめっき膜中に含有するイオウ
が１００ｐｐｍ未満ではＮｉめっき膜が緻密化しないた
め、耐食性向上の効果が得らず、８００ｐｐｍを越える
とめっき膜が脆化して磁石とＮｉめっき間の密着性が低
下することがわかる。From Table 1, in the R-TM-B system sintered magnetic alloy, Ni which was not sufficient in the conventional electric Ni plating was used.
It can be seen that the corrosion resistance of the plated film is significantly improved. Also, the amount of carbon contained in the Ni plating film is 50 ppm.
If it is less than 800 ppm, the effect of improving corrosion resistance cannot be obtained, and 800 ppm
If it exceeds the range, pits are likely to occur in the Ni plating film and the corrosion resistance deteriorates. On the other hand, if the content of sulfur in the Ni plating film is less than 100 ppm, the Ni plating film will not be densified, so that the effect of improving the corrosion resistance cannot be obtained. It can be seen that
【００１０】なお、本実施例ではＮｉめっき単層の例を
示したが、多層のめっき膜、例えばＣｕめっき膜とＮｉ
めっき膜の複合めっき膜とした場合でもＮｉめっき膜中
にカーボンとイオウを微量同時添加することによりＮｉ
めっき単層と同様の効果が得られる。また、本実施例で
はカーボンの微量添加法としてアノードをカーボナイズ
ドニッケルとし、イオウの微量添加法としてめっき液中
にサッカリンを添加する方法を示したが、他の方法によ
る添加法でも同様の効果を得ることができる。In this embodiment, an example of a Ni-plated single layer is shown, but a multilayered plated film such as a Cu-plated film and a Ni-plated film is used.
Even if it is a composite plating film of plating film, Ni and Ni can be added by adding a small amount of carbon and sulfur simultaneously.
The same effect as the plating single layer can be obtained. Further, in the present embodiment, carbonized nickel was used as the anode as a trace amount addition method of carbon, and a method of adding saccharin to the plating solution as a trace amount addition method of sulfur was shown. Obtainable.
【００１１】[0011]
【発明の効果】本発明により、希土類と鉄を主体とした
磁性合金において、従来のめっきでは不充分であった耐
食性の顕著な向上が図られた。According to the present invention, in the magnetic alloy mainly composed of rare earth and iron, the corrosion resistance, which was insufficient by the conventional plating, was remarkably improved.
Claims (1)
類元素の１種または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、一部を他の金属または非金属元素で置換してよ
い）５０〜９０％、Ｂ（ホウ素）０．２〜８％からなる
焼結磁性合金の表面にＮｉめっき膜を形成した耐食性焼
結磁性合金において、該Ｎｉめっき膜中のカーボン含有
量が５０〜８００ｐｐｍであり、かつイオウ含有量が１
００〜８００ｐｐｍであることを特徴とする耐食性焼結
磁性合金。1. R in a weight ratio (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 may be partially replaced with other metal or non-metal element) 50 to 90%, B (boron) 0.2 to 8 %, The carbon content in the Ni plating film is 50 to 800 ppm, and the sulfur content is 1
A corrosion-resistant sintered magnetic alloy, characterized in that the content is from 0.00 to 800 ppm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7133532A JPH08325677A (en) | 1995-05-31 | 1995-05-31 | Corrosion resistant sintered magnetic alloy |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7133532A JPH08325677A (en) | 1995-05-31 | 1995-05-31 | Corrosion resistant sintered magnetic alloy |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH08325677A true JPH08325677A (en) | 1996-12-10 |
Family
ID=15107010
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7133532A Pending JPH08325677A (en) | 1995-05-31 | 1995-05-31 | Corrosion resistant sintered magnetic alloy |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH08325677A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20060141281A1 (en) * | 2004-12-24 | 2006-06-29 | Tdk Corporation | R-T-B system permanent magnet and plating film |
| JP2008235948A (en) * | 2008-07-04 | 2008-10-02 | Tdk Corp | R-t-b based permanent magnet |
| JP2012204608A (en) * | 2011-03-25 | 2012-10-22 | Tdk Corp | Magnet member |
-
1995
- 1995-05-31 JP JP7133532A patent/JPH08325677A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20060141281A1 (en) * | 2004-12-24 | 2006-06-29 | Tdk Corporation | R-T-B system permanent magnet and plating film |
| JP2008235948A (en) * | 2008-07-04 | 2008-10-02 | Tdk Corp | R-t-b based permanent magnet |
| JP4730564B2 (en) * | 2008-07-04 | 2011-07-20 | Ｔｄｋ株式会社 | R-T-B permanent magnet |
| JP2012204608A (en) * | 2011-03-25 | 2012-10-22 | Tdk Corp | Magnet member |
| US9171668B2 (en) | 2011-03-25 | 2015-10-27 | Tdk Corporation | Magnet member |
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