JPH04276604A - R-tm-b permanent magnet with improved corrosion resistance - Google Patents
R-tm-b permanent magnet with improved corrosion resistanceInfo
- Publication number
- JPH04276604A JPH04276604A JP3062561A JP6256191A JPH04276604A JP H04276604 A JPH04276604 A JP H04276604A JP 3062561 A JP3062561 A JP 3062561A JP 6256191 A JP6256191 A JP 6256191A JP H04276604 A JPH04276604 A JP H04276604A
- Authority
- JP
- Japan
- Prior art keywords
- metal
- permanent magnet
- layer
- corrosion resistance
- 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
- 230000007797 corrosion Effects 0.000 title claims abstract description 20
- 238000005260 corrosion Methods 0.000 title claims abstract description 20
- 229910052751 metal Inorganic materials 0.000 claims abstract description 42
- 239000002184 metal Substances 0.000 claims abstract description 38
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims abstract description 8
- 229910052796 boron Inorganic materials 0.000 claims abstract description 7
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 7
- 229910052718 tin Inorganic materials 0.000 claims abstract description 7
- 229910018104 Ni-P Inorganic materials 0.000 claims abstract description 6
- 229910018536 Ni—P Inorganic materials 0.000 claims abstract description 6
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 6
- 229910052717 sulfur Inorganic materials 0.000 claims abstract description 6
- 239000011780 sodium chloride Substances 0.000 claims abstract description 4
- 229910052802 copper Inorganic materials 0.000 claims abstract description 3
- 229910052725 zinc Inorganic materials 0.000 claims abstract description 3
- 239000011247 coating layer Substances 0.000 claims description 20
- 239000010410 layer Substances 0.000 claims description 16
- 229910052761 rare earth metal Inorganic materials 0.000 claims description 5
- 229910052742 iron Inorganic materials 0.000 claims description 4
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 claims description 3
- 229910052723 transition metal Inorganic materials 0.000 claims description 3
- 229910052755 nonmetal Inorganic materials 0.000 claims description 2
- 150000003624 transition metals Chemical class 0.000 claims description 2
- 238000001465 metallisation Methods 0.000 claims 2
- 239000000203 mixture Substances 0.000 abstract description 2
- 238000000576 coating method Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 5
- 238000007747 plating Methods 0.000 description 5
- 238000000034 method Methods 0.000 description 4
- 230000003647 oxidation Effects 0.000 description 4
- 238000007254 oxidation reaction Methods 0.000 description 4
- 238000010298 pulverizing process Methods 0.000 description 3
- 239000011347 resin Substances 0.000 description 3
- 229920005989 resin Polymers 0.000 description 3
- 239000012300 argon atmosphere Substances 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- -1 composed of Fe Chemical class 0.000 description 2
- 238000007772 electroless plating Methods 0.000 description 2
- 238000009713 electroplating Methods 0.000 description 2
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 2
- 238000000465 moulding Methods 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 239000007921 spray Substances 0.000 description 2
- 238000007740 vapor deposition Methods 0.000 description 2
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 238000007743 anodising Methods 0.000 description 1
- 229910052787 antimony Inorganic materials 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 229910052733 gallium Inorganic materials 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 229910052732 germanium Inorganic materials 0.000 description 1
- 229910052735 hafnium Inorganic materials 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 239000011802 pulverized particle Substances 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 150000002910 rare earth metals Chemical class 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 239000002345 surface coating layer Substances 0.000 description 1
- 229910052715 tantalum Inorganic materials 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- 229910052727 yttrium Inorganic materials 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
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２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 permanent magnet whose corrosion resistance has been significantly improved by providing a two-layer metal coating layer on the surface of the magnet.
【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をふくむ希土類元素の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。BACKGROUND OF THE INVENTION As electric and electronic devices become more sophisticated and more compact, similar demands have been placed on permanent magnets, which are one of their components. In other words, in the past, the strongest permanent magnets were rare earth/cobalt (R-Co) based magnets, but in recent years, even stronger R-
TM-B permanent magnets have become popular (Japanese Unexamined Patent Publication No. 1986-46)
No. 008). Here, R is one type or a combination of two or more rare earth elements including Y, and TM is a transition metal center such as Fe or Co, partially substituted with other metal elements or nonmetal elements, B is boron. However, R-TM-
B-series permanent magnets have the problem of being extremely susceptible to rust. Therefore, in order to improve corrosion resistance, measures have been taken to provide an oxidation-resistant coating layer on the surface of a permanent magnet. As the type of coating layer, metal plating, oxidation-resistant resin, metal coating by vapor deposition method, etc. have been proposed.In particular, metal plating is considered to improve the corrosion resistance of R-TM-B permanent magnets with simple processing. It is attracting attention (Japanese Patent Application Laid-Open No. 60-54406
issue). Metal plating has the advantage that the surface coating layer has superior mechanical strength compared to oxidation-resistant resin, and 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、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。そ
のため、上記手法では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。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
供することある。[Problems to be Solved by the Invention] However, unlike oxidation-resistant resins, there are pinholes on the surface of the metal plating coating layer, so moisture will accumulate over time regardless of whether or not the coating layer itself is hygroscopic. There was a problem that it penetrated into the magnet body through pinholes and caused corrosion and deterioration. Therefore, with the above method, it was not possible to sufficiently improve corrosion resistance, which was a problem. Therefore, an object of the present invention is to provide a highly reliable R-TM-B permanent magnet with improved corrosion resistance.
【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、これを含む希土類元素の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Ｎｉ
，Ｎｉ−Ｓ，Ｎｉ−Ｐ，Ｃｕ，Ｃｒ，Ｓｎから選ばれた
１種の金属被覆層を下層として設け、その上に、Ｎｉ，
Ｎｉ−Ｓ，Ｎｉ−Ｐ，Ｃｒ，Ｓｎ，Ｚｎから選ばれた下
層金属とは異なる１種の金属被覆層を上層として設ける
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。また本発明は上層として、下層金属被覆層
よりも、５％ＮａＣｌにおける自然電位に関して１００
ｍＶ以上卑な金属被覆層を設けることを特徴としている
。素材表面に、自然電位の貴な金属被覆層を下層として
設け、その上層として自然電位の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、腐食は卑な上層が
アノード的に溶解することにより進行する。すなわち、
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、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
。上記防食作用について注意すべき点は、下層金属被覆
層よりも、５％ＮａＣｌにおける自然電位に関して１０
０ｍＶ以上卑な金属被覆層を上層として設けることであ
る。１００ｍＶ以上でないと、前述した２層金属被覆層
の防食効果を得ることができないため好ましくない。そ
のため上層としては、下層金属被覆層よりも、５％Ｎａ
Ｃｌにおける自然電位に関して１００ｍＶ以上卑な金属
被覆層を設けることが望ましい。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，Ｎｂ，Ｔａ，Ｍｏ，Ｇｅ，Ｓｂ，Ｓｎ，Ｂ
ｉ，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なう
。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５〜２０μｍが好ましい。[Means for Solving the Problems] The present invention provides R(
Here, R is 5 to 40% of one kind or a combination of two or more kinds of rare earth elements including this, TM (here, TM is a transition metal mainly composed of Fe, and a part of it is other metal elements or non-metallic elements). May be substituted with a metal element) 50-90%, B (boron) 0.
Ni on the surface of an R-TM-B permanent magnet consisting of 2 to 8%
, Ni-S, Ni-P, Cu, Cr, and Sn as the lower layer, and on top of that, Ni,
An R-TM-B permanent magnet with improved corrosion resistance characterized by providing an upper layer with a metal coating layer of one type different from the lower metal selected from Ni-S, Ni-P, Cr, Sn, and Zn. be. The present invention also provides an upper layer with a 100% higher natural potential at 5% NaCl than the lower metal coating layer.
It is characterized by providing a metal coating layer that is more base than mV. If a metal coating layer with a noble natural potential is provided as a lower layer on the surface of the material, and a metal coating layer with a base natural potential is provided as an upper layer, due to the relationship between the two corrosion cells, corrosion will occur as the noble upper layer acts as an anode. Proceeds by dissolving. That is,
By anodizing the upper layer and generating an anode effect,
It is thought that the noble lower layer is cathodically protected from corrosion, and the underlying layer is also protected at the same time. The present invention has the above-mentioned anticorrosion effect,
This improves the corrosion resistance of R-TM-B permanent magnets. The point to note regarding the above corrosion protection effect is that the natural potential at 5% NaCl is 10% higher than that of the lower metal coating layer.
A metal coating layer with a base value of 0 mV or more is provided as an upper layer. If it is less than 100 mV, it is not preferable because the above-mentioned anticorrosion effect of the two-layer metal coating layer cannot be obtained. Therefore, the upper layer is made of 5% Na than the lower metal coating layer.
It is desirable to provide a metal coating layer that is more base than 100 mV with respect to the natural potential in Cl. In the present invention, Fe
, Co, Ni, etc., depending on the purpose of addition, include Ga, Al, Ti, V, Cr, Mn,
Zr, Hf, Nb, Ta, Mo, Ge, Sb, Sn, B
i, Ni, etc., and the present invention can be applied to any R-TM-B.
It can also be applied to permanent magnets. Further, the manufacturing method may be a sintering method, a molten metal quenching method, or a modification thereof. Metal coating methods include electroplating,
This is done by either electroless plating or vapor deposition. An optimal coating method may be used depending on each metal, and the thickness of the metal coating layer is preferably 5 to 20 μm.
【０００５】[0005]
【実施例】Ｎｄ（Ｆｅ０．７Ｃｏ０．２Ｂ０．０７Ｇａ
０．０３）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
砕を行ない、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
条件で金属被覆を被覆し、これを試験片とした。試料番
号４〜６は比較例である。「被覆方法」欄中、Ａは電気
めっきを、Ｂは無電解めっきを表わす。[Example] Nd(Fe0.7Co0.2B0.07Ga
An alloy having a composition of 0.03)6.5 was produced by arc melting, and the obtained ingot was coarsely ground using a stamp mill and a disc mill. Thereafter, fine pulverization was performed with a jet mill using N2 gas as a pulverizing medium to obtain fine pulverization with 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 2Ton/cm2. This molded body was sintered in vacuum at 1090°C for 2 hours. The sintered body was cut into a size of 18 x 10 x 6 mm, and then heated at 900°C.
After being heated and held in an argon atmosphere for 2 hours, the sample was rapidly cooled and held in an argon atmosphere at a temperature of 600°C for 1 hour. The samples thus obtained were coated with a metal coating under the conditions shown in Table 1, and used as test pieces. Sample numbers 4 to 6 are comparative examples. In the "Coating method" column, A represents electroplating and B represents electroless plating.
【０００６】[0006]
【表１】[Table 1]
【０００７】表１に示した試料に関して、８０℃９０％
ＲＨでの１０００時間の耐食試験及び３５℃５％ＮａＣ
ｌでの２００時間の塩水噴霧試験を行なった。結果を表
２に示す。Regarding the samples shown in Table 1, 80°C 90%
1000 hours corrosion resistance test at RH and 35°C 5% NaC
A 200 hour salt spray test was conducted at l. The results are shown in Table 2.
【０００８】[0008]
【表２】[Table 2]
【０００９】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
。[0009] In Table 2, the results of the corrosion resistance test indicate changes in the external appearance of the sample, and the results of the salt spray test indicate the time required for red rust to develop. Table 2 shows that the permanent magnet according to the present invention can significantly improve corrosion resistance compared to conventional magnets.
【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。[Effects of the Invention] According to the present invention, a remarkable improvement in corrosion resistance, which was insufficient with conventional metal plating, has been achieved in a magnet mainly composed of rare earth elements and iron.
Claims (2)
類元素の１種又は２種以上の組合わせ）５〜４０％、Ｔ
Ｍ（ここでＴＭは、Ｆｅ，Ｃｏを中止とする遷移金属で
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、該永久磁石体の表
面に、Ｎｉ，Ｎｉ−Ｓ，Ｎｉ−Ｐ，Ｃｕ，Ｃｒ，Ｓｎか
ら選ばれた１種の金属被覆層を下層として設け、その上
にＮｉ，Ｎｉ−Ｓ，Ｎｉ−Ｐ，Ｃｒ，Ｓｎ，Ｚｎから選
ばれた下層金属とは異なる１種の金属被覆層を上層とし
て設け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。Claim 1: R (here, one or a combination of two or more rare earth elements including Y) 5 to 40% by weight, T
M (here, TM is a transition metal excluding Fe and Co, and may be partially replaced with other metal elements or non-metal elements) 50 to 90%, B (boron) 0.2 In the R-TM-B permanent magnet consisting of ~8%, the surface of the permanent magnet body is coated with one type of metal coating layer selected from Ni, Ni-S, Ni-P, Cu, Cr, and Sn. R with improved corrosion resistance characterized by providing as an upper layer a metal coating layer of one type different from the lower metal selected from Ni, Ni-S, Ni-P, Cr, Sn, and Zn. -TM-
B series permanent magnet.
よりも、５％ＮａＣｌにおける自然電位に関して１００
ｍＶ以上卑な金属被覆層を設けることを特徴とする請求
項１に記載の耐食性を改善したＲ−ＴＭ−Ｂ系永久磁石
。2. The upper layer has a lower metallization potential of 100% with respect to the natural potential at 5% NaCl than the lower metallization layer.
2. The R-TM-B permanent magnet with improved corrosion resistance according to claim 1, further comprising a metal coating layer which is more base than mV.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3062561A JPH04276604A (en) | 1991-03-04 | 1991-03-04 | R-tm-b permanent magnet with improved corrosion resistance |
| US07/770,809 US5275891A (en) | 1990-10-04 | 1991-10-04 | R-TM-B permanent magnet member having improved corrosion resistance and method of producing same |
| GB9121222A GB2249319B (en) | 1990-10-04 | 1991-10-04 | R-TM-B permanent magnet member having improved corrosion resistance and method of producing same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3062561A JPH04276604A (en) | 1991-03-04 | 1991-03-04 | R-tm-b permanent magnet with improved corrosion resistance |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04276604A true JPH04276604A (en) | 1992-10-01 |
Family
ID=13203820
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3062561A Pending JPH04276604A (en) | 1990-10-04 | 1991-03-04 | R-tm-b permanent magnet with improved corrosion resistance |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04276604A (en) |
-
1991
- 1991-03-04 JP JP3062561A patent/JPH04276604A/en active Pending
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