JP3834707B2 - Rust prevention treatment method for rare earth magnets - Google Patents
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- 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
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- 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
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Description
【０００１】
【発明の属する技術分野】
この発明は、希土類磁石の防錆処理方法に関し、更に詳細には、ブラストメディアの打撃力によって金属粉末を表面に付着させた希土類磁石を、更に樹脂で被覆する希土類磁石の防錆処理方法に関するものである。
【０００２】
【従来の技術】
Ｓｍ、Ｎｄ、Ｐｒ等の希土類元素の１種または２種以上を含む磁性材料の粉末をプレスで所要形状に成形した後、これを焼結して得られる例えばモータのロータ等に使用される希土類磁石は、経時的に錆がその表面に発生し易い。従ってモータ部品等にそのまま使用すると、耐久性の低下や故障の原因を招くことになる。そこで錆止めのために、希土類磁石の表面を樹脂被膜で被覆する対策が一般に採られている。希土類磁石の表面に樹脂被膜を形成する方法としては、スプレー塗装、電着塗装、浸漬塗装等が知られている。
【０００３】
前記スプレー塗装では、適切な樹脂塗料の選択と重ね塗りによって、実用上略満足できる耐食性を確保することは可能であるが、複雑な製品形状によっては被膜が肥大化し易く、また薄い被膜を形成する場合は膜厚の均一性を保持することが困難で、寸法精度が低くなる欠点がある。しかも、スプレー塗装では塗料のロスが多くなると共に、希土類磁石の反転作業の必要性から工程数も多くなり、コスト高になる難点が指摘される。
【０００４】
前記電着塗装においては、スプレー塗装よりも耐食性に優れると共に、１５〜３０μｍ程度の膜厚塗装ではスプレー塗装よりも均一な膜厚が得られるが、被膜形成上１０μｍ以下の薄膜塗装は原理的な面から極めて困難である。また、希土類磁石を個々に電極にセット・リセットする作業工程、および塗装後の電極の接触跡を個別にタッチアップ塗装する工程等が必要であり、特に小径のリング形状の希土類磁石に薄い被膜を施すのに適さない問題がある。
【０００５】
これに対し前記浸漬塗装は、スプレー塗装や電着塗装と比較して耐食性は劣るものの、安価かつ少ない工程で済むという利点があり、しかも薄い被膜の被覆処理も５μｍ程度から可能である。すなわち、耐食性の点で他の塗装方法より劣るものの、その他の点では充分な汎用性があるから、この浸漬塗装が多くの場合に実施されていた。
【０００６】
【発明が解決しようとする課題】
前記浸漬塗装では、均一な厚みの被膜を形成するのは困難で膜厚は不均一になり易く、また表面に空孔、溝等の空隙部が多い希土類磁石では、それらを完全に封孔したり充填することができず、後工程の乾燥・硬化処理時に内部ガスの膨張、噴出による膨れ、ピンホールが発生し、磁石の寸法精度が低下する難点が指摘される。
【０００７】
そこで、前述した浸漬塗装での問題点を改善する１つの提案が、本件出願人により特願平８−３２６５７号に係る「防錆被覆層を有するボンド磁石とその防錆被覆処理方法」として出願されている。この発明に係る方法は、浸漬塗装により磁石の表面を樹脂被膜で被覆する工程の前に、ブラストメディアとしてのステンレス球と金属粉末を入れた容器の内部に磁石を装入し、この容器を回転させたり振動することにより生ずるステンレス球の打撃力によって、金属粉末を磁石の表面に所定厚みで付着させるようになっている。すなわち、磁石の表面の空孔、溝等の空隙部を予め金属粉末で被覆することにより、後工程の乾燥・硬化処理時における膨れやピンホールの発生を好適に防止することができ、それなりに高く評価し得るものである。
【０００８】
しかし、前述した方法によっても、希土類磁石の充分な耐食性は得られず、短期間で錆が発生する難点が依然としてあった。このような状況にあって、低コストで、かつ高い耐食性が得られる防錆処理方法が希求されているのが現状である。
【０００９】
【発明の目的】
本発明は、前述した従来の技術に内在している前記欠点に鑑み、これを好適に解決するべく提案されたものであって、低コストで高い耐食性が得られる希土類磁石の防錆処理方法を提供することを目的とする。
【００１０】
【課題を解決するための手段】
前記課題を克服し、所期の目的を達成するため、本発明に係る希土類磁石の防錆処理方法は、
ブラストメディアの打撃力によって希土類磁石の表面に金属粉末を付着させ、得られた希土類磁石を樹脂溶液中に浸漬することで、その表面を樹脂で被覆する防錆処理方法において、
前記ブラストメディアによる金属粉末の付着工程の前に、前記金属粉末を添加したカップリング剤の溶液中に前記希土類磁石を浸漬し、該磁石の表面に予め金属粉末を付着させた状態で、前記ブラストメディアによる金属粉末の付着工程を行なうことを特徴とする。
【００１１】
前記課題を克服し、所期の目的を達成するため、本願の別の発明に係る希土類磁石の防錆処理方法は、
ブラストメディアの打撃力によって希土類磁石の表面に金属粉末を付着させ、得られた希土類磁石を樹脂溶液中に浸漬することで、その表面を樹脂で被覆する防錆処理方法において、
前記ブラストメディアによる金属粉末の付着工程を行なった後に、該金属粉末の付着を安定させる定着液に前記希土類磁石を浸漬して、該磁石の表面に対する金属粉末の付着を安定化させ、次いでその表面を樹脂で被覆することを特徴とする。
【００１２】
前記課題を克服し、所期の目的を達成するため、本願の更に別の発明に係る希土類磁石の防錆処理方法は、
ブラストメディアの打撃力によって希土類磁石の表面に金属粉末を付着させ、得られた希土類磁石を樹脂溶液中に浸漬することで、その表面を樹脂で被覆する防錆処理方法において、
前記ブラストメディアによる金属粉末の付着工程の前に、前記金属粉末を添加したカップリング剤の溶液中に前記希土類磁石を浸漬し、該磁石の表面に予め金属粉末を付着させた状態で、前記ブラストメディアによる金属粉末の付着工程を行ない、
次いで、前記金属粉末の付着を安定させる定着液に前記希土類磁石を浸漬して、該磁石の表面に対する金属粉末の付着を安定化させた状態で、その表面を樹脂で被覆するようにしたことを特徴とする。
【００１３】
【発明の実施の形態】
次に、本発明に係る希土類磁石の防錆処理方法につき、添付図面を参照しながら以下説明する。本発明は、ブラストメディアの打撃力によって希土類磁石の表面に金属粉末を付着する付着工程(バレル処理)の前または後、あるいは前後において、希土類磁石に所要の処理を施すことによって耐食性を向上させることを内容とする。なお、防錆処理方法が実施される希土類磁石は、Ｓｍ、Ｎｄ、Ｐｒ等の希土類元素の１種または２種以上を含む磁性材料の粉末にバインダーを添加して混練したものを、所要形状に圧縮成形すると共に加熱処理することにより得られる。
【００１４】
【第１実施例について】
図１は、第１実施例に係る希土類磁石の防錆処理方法の工程を示すフローチャートであって、先ず金属粉末として鱗片状のアルミニウム粉末を添加したカップリング溶液中に希土類磁石を浸漬し、カップリング剤の作用によって希土類磁石の表面全体にアルミニウム粉末を付着させる。この希土類磁石をドライヤーで乾燥させたり、または自然乾燥することで溶液の液切りを行なった後に、バレル処理に回される。なお、カップリング溶液の配合例としては、キシレン：７０.０ｗｔ％、ＭＥＫ(メチルエチルケトン)：２７.５ｗｔ％、オレイン酸：１.５ｗｔ％、シラン系のカップリング剤：１.０ｗｔ％、アルミニウム粉末：０.２〜２.５ｗｔ％のものが好適に用いられる。
【００１５】
次に、アルミニウム粉末を表面に付着させた希土類磁石を、ブラストメディアとしての多数のステンレス球と、前述した工程で使用した金属粉末と同じ鱗片状のアルミニウム粉末を所定量(例えば５００個の希土類磁石に対して０.５ｇ)を入れたバレルタンクの内部に装入し、この容器を回転させたり振動することにより生ずるステンレス球の打撃力によって、アルミニウム粉末を希土類磁石の表面に付着させる。このバレル処理を行なうに際し、前述したように希土類磁石の表面全体には予めアルミニウム粉末が付着しているので、当該バレル処理によるアルミニウム粉末の付着工程と相俟って、磁石表面の空孔、溝等の空隙部は確実にアルミニウム粉末で被覆される。また、バレル処理に要する時間を短縮することができる。
【００１６】
前記バレル処理により金属被膜が施された希土類磁石をステンレス球と分離し、これを水道水を用いて揺動洗浄(洗浄処理)することで、不完全に付着している過剰のアルミニウム粉末を除去する。また、洗浄処理が完了した希土類磁石を、ドライヤーを用いて乾燥させたり、自然乾燥させる。
【００１７】
そして、得られた希土類磁石を、エポキシ樹脂を７.０ｗｔ％含む樹脂溶液中に浸漬し、該樹脂溶液中から取出した希土類磁石を乾燥して液切りを行なった後に、約１４５℃のオーブン中において４５分間硬化処理を施す。これにより、希土類磁石の表面の空孔、溝等の空隙部がアルミニウム粉末で被覆され、更に樹脂で被覆された高い耐食性を有する希土類磁石が得られる。なお、樹脂溶液の配合例としては、エポキシ樹脂：７.０ｗｔ％、キシレン：８.０ｗｔ％、ＭＥＫ(メチルエチルケトン)：８５.０ｗｔ％、硬化剤：２.０ｗｔ％のものが好適に使用される。
【００１８】
【第１実施例の試験例について】
前述した第１実施例に係る防錆処理方法で、以下に示す３種類の配合例に係るカップリング溶液を用いた場合の夫々の希土類磁石と、従来の防錆処理方法により得られた希土類磁石を、８０℃×９５％の雰囲気中に置いて、錆の発生の有無を検査した結果を以下の表に示す。なお、バレル処理におけるバレルタンクには、カップリング溶液に添加されている金属粉末と同じものが入れられる。
(カップリング溶液の配合例)
▲１▼キシレン：７０.０ｗｔ％、ＭＥＫ(メチルエチルケトン)：２７.５ｗｔ％、オレイン酸：１.５ｗｔ％、カップリング剤：１.０ｗｔ％、アルミニウム粉末：０.２〜２.５ｗｔ％、
▲２▼キシレン：６０.０ｗｔ％、ＭＥＫ(メチルエチルケトン)：３７.５ｗｔ％、ドデシルベンゼンスルホン酸ナトリウム：０.５ｗｔ％、カップリング剤：１.０ｗｔ％、ニッケル粉末：０.２〜２.５ｗｔ％
▲３▼キシレン：７０.０ｗｔ％、ＭＥＫ(メチルエチルケトン)：２５.０ｗｔ％、ドデシルベンゼンスルホン酸ナトリウム：０.８ｗｔ％、カップリング剤：１.５ｗｔ％、銅粉末：０.２〜２.５ｗｔ％
【００１９】
【００２０】
すなわち、この試験結果から、バレル処理前に金属粉末が添加されたカップリング溶液中に希土類磁石を浸漬させることにより、耐食性(防錆効果)が向上することが明らかとなった。
【００２１】
【第２実施例について】
図２は、第２実施例に係る希土類磁石の防錆処理方法の工程を示すフローチャートであって、表面に処理が施されていない希土類磁石を、ステンレス球とアルミニウム粉末を入れたバレルタンクの内部に装入し、この容器を回転させたり振動することにより生ずるステンレス球の打撃力によって、アルミニウム粉末を希土類磁石の表面に付着させる(バレル処理)。
【００２２】
次に、前記バレル処理により金属被膜が施された希土類磁石をステンレス球と分離し、これを水道水を用いて揺動洗浄(洗浄処理)することで、不完全に付着している過剰のアルミニウム粉末を除去する。この希土類磁石を、メタアクリル酸エステル１０ｗｔ％、純水(３０℃〜４０℃)９０ｗｔ％の定着液に浸漬する。その後、９０℃の温風で１０分間加熱することで液切りを行なう。このように、金属被膜が施された希土類磁石を定着液に浸漬することで、アルミニウム粉末の希土類磁石に対する付着が安定化し、後工程における粉末の剥離等が好適に防止される。
【００２３】
そして、得られた希土類磁石を、エポキシ樹脂を７.０ｗｔ％含む前述したと同じ樹脂溶液中に浸漬し、該樹脂溶液中から取出した希土類磁石を乾燥して液切りを行なった後に、約１４５℃のオーブン中において４５分間硬化処理を施す。これにより、希土類磁石の表面の空孔、溝等の空隙部がアルミニウム粉末で被覆され、更に樹脂で被覆された高い耐食性を有する希土類磁石が得られる。
【００２４】
【第２実施例の試験例について】
前述した第２実施例に係る防錆処理方法により得られた希土類磁石と、従来の防錆処理方法により得られた希土類磁石を、前述した第１実施例の試験例と同一の条件で検査した結果を以下の表に示す。
【００２５】
【００２６】
【第３実施例について】
図３は、第３実施例に係る希土類磁石の防錆処理方法の工程を示すフローチャートであって、先ず鱗片状のアルミニウム粉末を添加したカップリング溶液中に希土類磁石を浸漬し、カップリング剤の作用によって希土類磁石の表面全体にアルミニウム粉末を付着させる。この希土類磁石を乾燥(液切り)させた後、第１実施例と同様のバレル処理を行なうことで、アルミニウム粉末を希土類磁石の表面に付着させる。
【００２７】
次に、前記バレル処理により金属被膜が施された希土類磁石を洗浄処理して、不完全に付着している過剰のアルミニウム粉末を除去した後、該希土類磁石を第２実施例と同様の定着液に浸漬する。また、この希土類磁石の液切り加熱を行なう。そして、得られた希土類磁石を、前記実施例と同様のエポキシ樹脂を７.０ｗｔ％含む樹脂溶液中に浸漬し、該樹脂溶液中から取出した希土類磁石を乾燥して液切りを行なった後に、約１４５℃のオーブン中において４５分間硬化処理を施す。第３実施例では、更に希土類磁石をエポキシ樹脂を７.０ｗｔ％含む樹脂溶液中に浸漬して液切りを行なった後に、約１４５℃のオーブン中において４５分間硬化処理する工程を繰返す。
【００２８】
すなわち、第３実施例では、バレル処理を行なう前に、希土類磁石の表面全体に予めアルミニウム粉末を付着させることで、バレル処理により磁石表面の空孔、溝等の空隙部をアルミニウム粉末で確実に被覆することができる。またバレル処理後に、金属被膜が施された希土類磁石を定着液に浸漬することで、アルミニウム粉末の希土類磁石に対する付着が安定化し、後工程における粉末の剥離等が好適に防止される。従って、希土類磁石の表面全体がアルミニウム粉末で被覆され、更に樹脂で被覆された高い耐食性を有する希土類磁石が得られる。
【００２９】
【第３実施例の試験例について】
前述した第３実施例に係る防錆処理方法で、前述した３種類(▲１▼,▲２▼,▲３▼)の配合例に係るカップリング溶液を用いた場合の夫々の希土類磁石と、従来の防錆処理方法により得られた希土類磁石を、前述した第１実施例の試験例と同一の条件で検査した結果を以下の表に示す。なお、定着液については第２実施例と同様のものを使用した。
【００３０】
【００３１】
前記カップリング剤としては、シラン系の他に、チタネート系やアルミニウム系等が適宜に使用される。また、希土類磁石の表面に付着させる金属粉末としては、アルミニウム粉末に限らず、ニッケル粉末や銅粉末等であってもよい。更に、希土類磁石の表面を被覆する樹脂もエポキシ系に限らず、フェノール系、アクリル系、ポリアミド系、ナイロン系、ポリ塩化ビニル系、フタル酸エステル系、ポリエステル系、ポリプロン系、ポリオレフィン系等の樹脂も適用し得る。
【００３２】
なお、実施例のバレル処理は、バレルタンクを回転させたり振動することによりブラストメディアの打撃力を得るようにしたが、本願はこれに限定されるものでなく、タンクに設けたノズルからブラストメディアと金属粉末とを混合したブラスト媒体を空気圧により希土類磁石に吹付けることにより、該磁石の表面に所定厚みで金属粉末を付着させるものであってもよい。またブラストメディアとしては、ステンレス球に限らず、硬質めっきを施したスチール球、ニッケル球、銅球等を適宜に使用し得る。
【００３３】
【発明の効果】
以上説明した如く、本発明に係る希土類磁石の防錆処理方法によれば、ブラストメディアによる金属粉末の付着工程の前に、希土類磁石の表面に予め金属粉末をカップリング剤により付着させることにより、その耐食性を向上させることができる。また、ブラストメディアによる金属粉末の付着工程を行なった後に、表面に付着された金属粉末を定着液によって安定化させることで、その耐食性を向上させることができる。更には、ブラストメディアによる金属粉末の付着工程の前後に、前述した夫々の処理を施すことで、その耐食性が更に向上する。しかも、浸漬塗装による樹脂の被覆処理は低コストであるので、コストが低くかつ高い耐食性を有する希土類磁石が得られる。
【図面の簡単な説明】
【図１】本発明の第１実施例に係る希土類磁石の防錆処理方法の工程を示すフローチャート図である。
【図２】本発明の第２実施例に係る希土類磁石の防錆処理方法の工程を示すフローチャート図である。
【図３】本発明の第３実施例に係る希土類磁石の防錆処理方法の工程を示すフローチャート図である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rust prevention treatment method for a rare earth magnet, and more particularly to a rust prevention treatment method for a rare earth magnet in which a rare earth magnet having a metal powder adhered to its surface by the impact force of a blast medium is further coated with a resin. It is.
[0002]
[Prior art]
A rare earth element used for, for example, a motor rotor obtained by forming a powder of a magnetic material containing one or more rare earth elements such as Sm, Nd, and Pr into a required shape by pressing and then sintering the powder. Magnets tend to generate rust on the surface over time. Therefore, if it is used as it is for a motor part or the like, it will cause a decrease in durability or cause of failure. Therefore, in order to prevent rust, measures are generally taken to coat the surface of the rare earth magnet with a resin film. As a method for forming a resin film on the surface of a rare earth magnet, spray coating, electrodeposition coating, immersion coating, and the like are known.
[0003]
In the spray coating, it is possible to ensure corrosion resistance that is substantially satisfactory in practice by selecting an appropriate resin paint and overcoating. However, depending on the complicated product shape, the coating tends to enlarge, and a thin coating is formed. In this case, it is difficult to maintain the uniformity of the film thickness, and there is a disadvantage that the dimensional accuracy is lowered. In addition, spray coating increases the loss of paint and increases the number of processes due to the necessity of reversing the rare earth magnet, which raises the difficulty of increasing costs.
[0004]
In the electrodeposition coating, the corrosion resistance is superior to that of the spray coating, and a film thickness of about 15 to 30 μm can provide a more uniform film thickness than the spray coating. It is extremely difficult from the aspect. In addition, it is necessary to set and reset the rare earth magnets individually on the electrodes, and to touch up and paint the contact marks of the electrodes after painting. Especially, a thin film is applied to the small-diameter ring-shaped rare earth magnets. There is a problem that is not suitable to apply.
[0005]
On the other hand, the dip coating is less in corrosion resistance than spray coating or electrodeposition coating, but has an advantage that it is inexpensive and requires only a small number of steps, and a thin film can be coated from about 5 μm. That is, although it is inferior to other coating methods in terms of corrosion resistance, it is sufficiently versatile in other respects, so this dip coating has been carried out in many cases.
[0006]
[Problems to be solved by the invention]
In the dip coating, it is difficult to form a film with a uniform thickness and the film thickness tends to be non-uniform, and in the rare earth magnet having many voids such as holes and grooves on the surface, they are completely sealed. However, it is pointed out that the internal gas expands during the subsequent drying / curing process, expands due to jetting, pinholes occur, and the dimensional accuracy of the magnet decreases.
[0007]
Therefore, one proposal for improving the above-described problems in the dip coating was filed by the applicant as “bond magnet having a rust-proof coating layer and its rust-proof coating treatment method” according to Japanese Patent Application No. 8-32657. Has been. In the method according to the present invention, before the step of coating the surface of the magnet with a resin coating by dip coating, the magnet is inserted into a container containing stainless steel balls and metal powder as blast media, and the container is rotated. The metal powder is made to adhere to the surface of the magnet with a predetermined thickness by the striking force of the stainless sphere generated by causing or vibrating. That is, by covering the voids such as vacancies and grooves on the surface of the magnet with the metal powder in advance, it is possible to suitably prevent the occurrence of swelling and pinholes during the subsequent drying / curing process. It can be highly appreciated.
[0008]
However, even with the above-described method, sufficient corrosion resistance of the rare earth magnet cannot be obtained, and there is still a problem that rust is generated in a short period of time. Under such circumstances, there is a demand for a rust-proofing method that can provide high corrosion resistance at low cost.
[0009]
OBJECT OF THE INVENTION
The present invention has been proposed in view of the above-mentioned drawbacks inherent in the prior art described above, and has been proposed to solve this problem, and a method for rust-proofing a rare earth magnet that can provide high corrosion resistance at low cost is provided. The purpose is to provide.
[0010]
[Means for Solving the Problems]
In order to overcome the above-mentioned problems and achieve the intended purpose, the rust preventive treatment method of the rare earth magnet according to the present invention,
In the rust prevention treatment method of coating the surface with resin by immersing the obtained rare earth magnet in a resin solution by attaching metal powder to the surface of the rare earth magnet by the impact force of the blast media,
Before the step of attaching the metal powder with the blast media, the rare earth magnet is immersed in a solution of a coupling agent to which the metal powder is added, and the blasting is performed in a state where the metal powder is attached to the surface of the magnet in advance. It is characterized in that a metal powder attaching process using media is performed.
[0011]
In order to overcome the above-mentioned problems and achieve the intended purpose, a rust prevention method for a rare earth magnet according to another invention of the present application,
In the rust prevention treatment method of coating the surface with resin by immersing the obtained rare earth magnet in a resin solution by attaching metal powder to the surface of the rare earth magnet by the impact force of the blast media,
After performing the deposition step of the metal powder by the blast media, and immersed the rare earth magnet fixer to stabilize the adhesion of the metal powder, to stabilize the adhesion of the metal powder to the surface of the magnet, then its The surface is covered with a resin.
[0012]
In order to overcome the above-mentioned problems and achieve the intended purpose, a rust prevention method for a rare earth magnet according to still another invention of the present application,
In the rust prevention treatment method of coating the surface with resin by immersing the obtained rare earth magnet in a resin solution by attaching metal powder to the surface of the rare earth magnet by the impact force of the blast media,
Before the step of attaching the metal powder with the blast media, the rare earth magnet is immersed in a solution of a coupling agent to which the metal powder is added, and the blasting is performed in a state where the metal powder is attached to the surface of the magnet in advance. Perform the metal powder adhesion process with media,
Then immersed the rare earth magnet fixer to stabilize the adhesion of the metal powder, in a state of attaching the stabilized metal powder to the surface of the magnet, it has its surface so as to cover with resin It is characterized by.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Next, a method for treating rust of a rare earth magnet according to the present invention will be described below with reference to the accompanying drawings. The present invention improves the corrosion resistance by applying the required treatment to the rare earth magnet before, after, or before or after the adhesion process (barrel treatment) for attaching the metal powder to the surface of the rare earth magnet by the impact force of the blast media. Is the content. In addition, the rare earth magnet to be subjected to the rust prevention treatment method is obtained by adding a binder to a magnetic material powder containing one or more rare earth elements such as Sm, Nd, and Pr and kneading them into a required shape. It is obtained by compression molding and heat treatment.
[0014]
[About the first embodiment]
FIG. 1 is a flowchart showing the steps of a rust prevention method for a rare earth magnet according to a first embodiment. First, a rare earth magnet is immersed in a coupling solution to which a scaly aluminum powder is added as a metal powder, Aluminum powder is adhered to the entire surface of the rare earth magnet by the action of the ring agent. The rare earth magnet is dried with a drier or is dried naturally, and then the solution is drained, followed by barrel treatment. As examples of the coupling solution, xylene: 70.0 wt%, MEK (methyl ethyl ketone): 27.5 wt%, oleic acid: 1.5 wt%, silane coupling agent: 1.0 wt%, aluminum powder : 0.2-2.5 wt% is preferably used.
[0015]
Next, a rare earth magnet with aluminum powder adhered to the surface is made of a number of stainless steel spheres as blast media and a predetermined amount of scaly aluminum powder same as the metal powder used in the above-described process (for example, 500 rare earth magnets). The aluminum powder is attached to the surface of the rare earth magnet by the striking force of the stainless sphere generated by rotating or vibrating the container. When performing this barrel treatment, as described above, since the aluminum powder is preliminarily adhered to the entire surface of the rare earth magnet, in combination with the aluminum powder deposition step by the barrel treatment, holes and grooves on the magnet surface are formed. Such voids are reliably covered with aluminum powder. In addition, the time required for barrel processing can be shortened.
[0016]
The rare earth magnet coated with the metal film by the barrel treatment is separated from the stainless steel sphere, and this is subjected to rocking washing (washing treatment) using tap water, thereby removing the excessively adhering aluminum powder. To do. In addition, the rare earth magnet that has been cleaned is dried using a dryer or is naturally dried.
[0017]
Then, the obtained rare earth magnet was immersed in a resin solution containing 7.0 wt% of an epoxy resin, and the rare earth magnet taken out from the resin solution was dried and drained, and then in an oven at about 145 ° C. And curing for 45 minutes. As a result, a rare earth magnet having high corrosion resistance in which voids such as vacancies and grooves on the surface of the rare earth magnet are coated with the aluminum powder and further coated with the resin can be obtained. In addition, as a compounding example of the resin solution, epoxy resin: 7.0 wt%, xylene: 8.0 wt%, MEK (methyl ethyl ketone): 85.0 wt%, and curing agent: 2.0 wt% are preferably used. .
[0018]
[Test example of the first embodiment]
In the antirust treatment method according to the first embodiment described above, each rare earth magnet in the case of using the coupling solutions according to the following three kinds of blending examples, and the rare earth magnet obtained by the conventional antirust treatment method Is placed in an atmosphere of 80 ° C. × 95%, and the results of inspection for the occurrence of rust are shown in the following table. In addition, the same thing as the metal powder currently added to the coupling solution is put into the barrel tank in barrel processing.
(Example of coupling solution formulation)
(1) Xylene: 70.0 wt%, MEK (methyl ethyl ketone): 27.5 wt%, oleic acid: 1.5 wt%, coupling agent: 1.0 wt%, aluminum powder: 0.2-2.5 wt%,
(2) Xylene: 60.0 wt%, MEK (methyl ethyl ketone): 37.5 wt%, sodium dodecylbenzenesulfonate: 0.5 wt%, coupling agent: 1.0 wt%, nickel powder: 0.2-2.5 wt %
(3) Xylene: 70.0 wt%, MEK (methyl ethyl ketone): 25.0 wt%, sodium dodecylbenzenesulfonate: 0.8 wt%, coupling agent: 1.5 wt%, copper powder: 0.2-2.5 wt %
[0019]
[0020]
That is, from this test result, it was revealed that the corrosion resistance (rust prevention effect) is improved by immersing the rare earth magnet in the coupling solution to which the metal powder is added before the barrel treatment.
[0021]
[About the second embodiment]
FIG. 2 is a flowchart showing a process of a rust prevention treatment method for a rare earth magnet according to a second embodiment, in which a rare earth magnet whose surface is not treated is placed inside a barrel tank containing stainless steel balls and aluminum powder. The aluminum powder is adhered to the surface of the rare earth magnet by the striking force of the stainless sphere generated by rotating or vibrating the container (barrel treatment).
[0022]
Next, the rare earth magnet coated with the metal film by the barrel treatment is separated from the stainless steel sphere, and this is subjected to rocking washing (washing treatment) using tap water, so that excess aluminum adhered incompletely. Remove powder. This rare earth magnet is immersed in a fixing solution of 10 wt% methacrylic acid ester and 90 wt% pure water (30 ° C. to 40 ° C.). Thereafter, the liquid is removed by heating with warm air of 90 ° C. for 10 minutes. As described above, by immersing the rare earth magnet coated with the metal film in the fixing solution, the adhesion of the aluminum powder to the rare earth magnet is stabilized, and the exfoliation of the powder in the subsequent process is suitably prevented.
[0023]
Then, the obtained rare earth magnet was immersed in the same resin solution as described above containing 7.0 wt% of epoxy resin, and the rare earth magnet taken out from the resin solution was dried and drained. Curing is performed for 45 minutes in an oven at 0 ° C. As a result, a rare earth magnet having high corrosion resistance in which voids such as vacancies and grooves on the surface of the rare earth magnet are coated with the aluminum powder and further coated with the resin can be obtained.
[0024]
[Test example of the second embodiment]
The rare earth magnet obtained by the rust prevention treatment method according to the second embodiment described above and the rare earth magnet obtained by the conventional rust prevention treatment method were inspected under the same conditions as the test example of the first embodiment described above. The results are shown in the table below.
[0025]
[0026]
[About the third embodiment]
FIG. 3 is a flowchart showing the steps of a rust prevention method for a rare earth magnet according to a third embodiment. First, the rare earth magnet is immersed in a coupling solution to which scaly aluminum powder is added, The action causes aluminum powder to adhere to the entire surface of the rare earth magnet. After this rare earth magnet is dried (liquid drained), the same barrel treatment as in the first embodiment is performed to adhere aluminum powder to the surface of the rare earth magnet.
[0027]
Next, the rare earth magnet coated with the metal film by the barrel treatment is washed to remove the excessively adhering aluminum powder, and then the rare earth magnet is fixed to the same fixing solution as in the second embodiment. Immerse in. Further, liquid heating of the rare earth magnet is performed. And after immersing the obtained rare earth magnet in a resin solution containing 7.0 wt% of the same epoxy resin as in the above example, drying the rare earth magnet taken out from the resin solution, Curing is performed in an oven at about 145 ° C. for 45 minutes. In the third embodiment, the process is further repeated for 45 minutes in an oven at about 145 ° C. after the rare earth magnet is immersed in a resin solution containing 7.0 wt% of an epoxy resin and drained.
[0028]
That is, in the third embodiment, before carrying out the barrel treatment, the aluminum powder is adhered to the entire surface of the rare earth magnet in advance, so that the voids such as vacancies and grooves on the magnet surface are reliably made of aluminum powder by the barrel treatment. Can be coated. In addition, by immersing the rare earth magnet coated with the metal film in the fixing solution after the barrel treatment, the adhesion of the aluminum powder to the rare earth magnet is stabilized, and the exfoliation of the powder in the subsequent process is suitably prevented. Therefore, a rare earth magnet having a high corrosion resistance in which the entire surface of the rare earth magnet is coated with aluminum powder and further coated with a resin can be obtained.
[0029]
[Test example of the third embodiment]
Each of the rare earth magnets in the case of using the coupling solution according to the above-described three types ((1), (2), (3)) of the rust preventive treatment method according to the third embodiment, The following table shows the results of inspecting the rare earth magnet obtained by the conventional rust prevention treatment method under the same conditions as the test example of the first embodiment described above. Note that the same fixer as in the second embodiment was used.
[0030]
[0031]
As the coupling agent, titanate and aluminum are appropriately used in addition to silane. Further, the metal powder attached to the surface of the rare earth magnet is not limited to aluminum powder, but may be nickel powder, copper powder, or the like. Furthermore, the resin that coats the surface of the rare earth magnet is not limited to an epoxy resin, but a phenol resin, an acrylic resin, a polyamide resin, a nylon resin, a polyvinyl chloride resin, a phthalate ester resin, a polyester resin, a polyprone resin, a polyolefin resin, or the like. Can also be applied.
[0032]
In the barrel processing of the embodiment, the impact force of the blasting medium is obtained by rotating or vibrating the barrel tank, but the present application is not limited to this, and the blasting medium is provided from the nozzle provided in the tank. The metal powder may be adhered to the surface of the magnet by spraying a rare earth magnet by air pressure with a blast medium in which the powder and the metal powder are mixed. Further, the blast media is not limited to stainless steel spheres, and steel spheres, nickel spheres, copper spheres and the like subjected to hard plating can be appropriately used.
[0033]
【The invention's effect】
As described above, according to the rust preventive treatment method of the rare earth magnet according to the present invention, by attaching the metal powder in advance to the surface of the rare earth magnet with a coupling agent before the metal powder attaching step with the blast media, Its corrosion resistance can be improved. Moreover, after performing the adhesion process of the metal powder by a blasting medium, the corrosion resistance can be improved by stabilizing the metal powder adhered to the surface with a fixing solution. Furthermore, the corrosion resistance is further improved by applying each of the above-described treatments before and after the step of attaching the metal powder with the blast media. Moreover, since the resin coating process by dip coating is low cost, a rare earth magnet having low cost and high corrosion resistance can be obtained.
[Brief description of the drawings]
FIG. 1 is a flowchart showing the steps of a rust prevention method for a rare earth magnet according to a first embodiment of the present invention.
FIG. 2 is a flowchart showing steps of a rust prevention method for a rare earth magnet according to a second embodiment of the present invention.
FIG. 3 is a flowchart showing the steps of a rust preventive treatment method for a rare earth magnet according to a third embodiment of the present invention.
Claims (5)
前記ブラストメディアによる金属粉末の付着工程の前に、前記金属粉末を添加したカップリング剤の溶液中に前記希土類磁石を浸漬し、該磁石の表面に予め金属粉末を付着させた状態で、前記ブラストメディアによる金属粉末の付着工程を行なう
ことを特徴とする希土類磁石の防錆処理方法。In the rust prevention treatment method of coating the surface with resin by immersing the obtained rare earth magnet in a resin solution by attaching metal powder to the surface of the rare earth magnet by the impact force of the blast media,
Before the step of attaching the metal powder with the blast media, the rare earth magnet is immersed in a solution of a coupling agent to which the metal powder is added, and the blasting is performed in a state where the metal powder is attached to the surface of the magnet in advance. A method for rust-proofing a rare earth magnet, comprising performing a metal powder adhesion process using a medium.
前記ブラストメディアによる金属粉末の付着工程を行なった後に、該金属粉末の付着を安定させる定着液に前記希土類磁石を浸漬して、該磁石の表面に対する金属粉末の付着を安定化させ、次いでその表面を樹脂で被覆する
ことを特徴とする希土類磁石の防錆処理方法。In the rust prevention treatment method of coating the surface with resin by immersing the obtained rare earth magnet in a resin solution by attaching metal powder to the surface of the rare earth magnet by the impact force of the blast media,
After performing the deposition step of the metal powder by the blast media, and immersed the rare earth magnet fixer to stabilize the adhesion of the metal powder, to stabilize the adhesion of the metal powder to the surface of the magnet, then its A method for treating rust of rare earth magnets, wherein the surface is coated with a resin.
前記ブラストメディアによる金属粉末の付着工程の前に、前記金属粉末を添加したカップリング剤の溶液中に前記希土類磁石を浸漬し、該磁石の表面に予め金属粉末を付着させた状態で、前記ブラストメディアによる金属粉末の付着工程を行ない、
次いで、前記金属粉末の付着を安定させる定着液に前記希土類磁石を浸漬して、該磁石の表面に対する金属粉末の付着を安定化させた状態で、その表面を樹脂で被覆するようにした
ことを特徴とする希土類磁石の防錆処理方法。In the rust prevention treatment method of coating the surface with resin by immersing the obtained rare earth magnet in a resin solution by attaching metal powder to the surface of the rare earth magnet by the impact force of the blast media,
Before the step of attaching the metal powder with the blast media, the rare earth magnet is immersed in a solution of a coupling agent to which the metal powder is added, and the blasting is performed in a state where the metal powder is attached to the surface of the magnet in advance. Perform the metal powder adhesion process with media,
Then immersed the rare earth magnet fixer to stabilize the adhesion of the metal powder, in a state of attaching the stabilized metal powder to the surface of the magnet, it has its surface so as to cover with resin A method for treating rust of rare earth magnets.
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| JP05224797A JP3834707B2 (en) | 1997-02-19 | 1997-02-19 | Rust prevention treatment method for rare earth magnets |
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| JP05224797A JP3834707B2 (en) | 1997-02-19 | 1997-02-19 | Rust prevention treatment method for rare earth magnets |
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| JP4162884B2 (en) | 2001-11-20 | 2008-10-08 | 信越化学工業株式会社 | Corrosion-resistant rare earth magnet |
| CN100398615C (en) * | 2005-06-07 | 2008-07-02 | 武汉材料保护研究所 | Coating process for neodymium-iron-boron permanent magnetic material |
| JP4506708B2 (en) * | 2006-03-31 | 2010-07-21 | Ｔｄｋ株式会社 | Rare earth magnet manufacturing method |
| JP5348110B2 (en) * | 2010-10-28 | 2013-11-20 | Ｔｄｋ株式会社 | Rare earth magnet, rare earth magnet manufacturing method and rotating machine |
| JP6246500B2 (en) * | 2013-05-28 | 2017-12-13 | 日本電産サンキョー株式会社 | Rare earth magnet manufacturing method |
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