JPH04328804A - Corrosion-proof permanent magnet and manufacture thereof - Google Patents
Corrosion-proof permanent magnet and manufacture thereofInfo
- Publication number
- JPH04328804A JPH04328804A JP3124870A JP12487091A JPH04328804A JP H04328804 A JPH04328804 A JP H04328804A JP 3124870 A JP3124870 A JP 3124870A JP 12487091 A JP12487091 A JP 12487091A JP H04328804 A JPH04328804 A JP H04328804A
- Authority
- JP
- Japan
- Prior art keywords
- permanent magnet
- corrosion
- magnet
- phase
- exposed
- 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.)
- Granted
Links
- 238000004519 manufacturing process Methods 0.000 title claims description 8
- SZVJSHCCFOBDDC-UHFFFAOYSA-N ferrosoferric oxide Chemical compound O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 claims abstract description 18
- 239000002344 surface layer Substances 0.000 claims abstract description 18
- RKTYLMNFRDHKIL-UHFFFAOYSA-N copper;5,10,15,20-tetraphenylporphyrin-22,24-diide Chemical compound [Cu+2].C1=CC(C(=C2C=CC([N-]2)=C(C=2C=CC=CC=2)C=2C=CC(N=2)=C(C=2C=CC=CC=2)C2=CC=C3[N-]2)C=2C=CC=CC=2)=NC1=C3C1=CC=CC=C1 RKTYLMNFRDHKIL-UHFFFAOYSA-N 0.000 claims abstract description 17
- 238000010438 heat treatment Methods 0.000 claims abstract description 14
- 239000011347 resin Substances 0.000 claims abstract description 14
- 229920005989 resin Polymers 0.000 claims abstract description 14
- 230000001590 oxidative effect Effects 0.000 claims abstract description 13
- 239000010410 layer Substances 0.000 claims abstract description 12
- 230000032683 aging Effects 0.000 claims abstract description 11
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N iron oxide Inorganic materials [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 claims abstract description 10
- 238000005260 corrosion Methods 0.000 claims description 33
- 230000007797 corrosion Effects 0.000 claims description 33
- 238000000034 method Methods 0.000 claims description 9
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 8
- 230000003647 oxidation Effects 0.000 claims description 8
- 238000007254 oxidation reaction Methods 0.000 claims description 8
- 229910052760 oxygen Inorganic materials 0.000 claims description 8
- 239000001301 oxygen Substances 0.000 claims description 8
- 238000000227 grinding Methods 0.000 claims description 5
- 239000011261 inert gas Substances 0.000 claims description 3
- 229910052742 iron Inorganic materials 0.000 claims description 3
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 claims description 2
- 229910000859 α-Fe Inorganic materials 0.000 abstract description 9
- 229910003145 α-Fe2O3 Inorganic materials 0.000 abstract description 9
- 239000013078 crystal Substances 0.000 abstract description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 11
- 238000000576 coating method Methods 0.000 description 8
- 239000011248 coating agent Substances 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- 238000004381 surface treatment Methods 0.000 description 5
- 230000000052 comparative effect Effects 0.000 description 4
- 230000007423 decrease Effects 0.000 description 4
- 238000007598 dipping method Methods 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 238000004070 electrodeposition Methods 0.000 description 3
- 238000009713 electroplating Methods 0.000 description 3
- 239000003822 epoxy resin Substances 0.000 description 3
- 230000004907 flux Effects 0.000 description 3
- 229920000647 polyepoxide Polymers 0.000 description 3
- -1 tetragonal compound Chemical class 0.000 description 3
- 229910052692 Dysprosium Inorganic materials 0.000 description 2
- 229910052779 Neodymium Inorganic materials 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 238000007772 electroless plating Methods 0.000 description 2
- 150000004679 hydroxides Chemical class 0.000 description 2
- 238000009776 industrial production Methods 0.000 description 2
- 230000005389 magnetism Effects 0.000 description 2
- 238000007747 plating Methods 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 229910052761 rare earth metal Inorganic materials 0.000 description 2
- 239000007921 spray Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 230000004584 weight gain Effects 0.000 description 2
- 235000019786 weight gain Nutrition 0.000 description 2
- 230000004580 weight loss Effects 0.000 description 2
- 239000004925 Acrylic resin Substances 0.000 description 1
- 229920000178 Acrylic resin Polymers 0.000 description 1
- 102100036439 Amyloid beta precursor protein binding family B member 1 Human genes 0.000 description 1
- 229910052691 Erbium Inorganic materials 0.000 description 1
- 229910052693 Europium Inorganic materials 0.000 description 1
- 229910052688 Gadolinium Inorganic materials 0.000 description 1
- 229910052689 Holmium Inorganic materials 0.000 description 1
- 101000928670 Homo sapiens Amyloid beta precursor protein binding family B member 1 Proteins 0.000 description 1
- 229910052765 Lutetium Inorganic materials 0.000 description 1
- 229910052777 Praseodymium Inorganic materials 0.000 description 1
- 229910052772 Samarium Inorganic materials 0.000 description 1
- 229910052775 Thulium Inorganic materials 0.000 description 1
- 229910052769 Ytterbium Inorganic materials 0.000 description 1
- 239000003929 acidic solution Substances 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 229910000272 alkali metal oxide Inorganic materials 0.000 description 1
- 239000012670 alkaline solution Substances 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
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 229910003460 diamond Inorganic materials 0.000 description 1
- 239000010432 diamond Substances 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 239000007849 furan resin Substances 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 239000000088 plastic resin Substances 0.000 description 1
- 229920001296 polysiloxane Polymers 0.000 description 1
- 150000002910 rare earth metals Chemical class 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000007592 spray painting technique Methods 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 229920002803 thermoplastic polyurethane Polymers 0.000 description 1
- 238000004506 ultrasonic cleaning Methods 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
- 229910052727 yttrium 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
Abstract
Description
【０００１】0001
【産業上の利用分野】この発明は、高磁気特性を有しか
つ耐食性にすぐれたＦｅ−Ｂ−Ｒ系永久磁石に係り、研
削加工後に熱処理を施し、磁石表面を水分に対して安定
な化合物に変化させ、耐食性を著しく向上させたＦｅ−
Ｂ−Ｒ系永久磁石とその製造方法に関する。[Industrial Application Field] This invention relates to Fe-B-R permanent magnets that have high magnetic properties and excellent corrosion resistance. Fe-
This invention relates to a B-R permanent magnet and its manufacturing method.
【０００２】0002
【従来の技術】今日、高性能永久磁石として代表的なＦ
ｅ−Ｂ−Ｒ系永久磁石（特開昭５９−４６００８号）は
、三元系正方晶化合物の主相とＲリッチ相を有する組織
にて高磁石特性を発現し、ｉＨｃが２５ｋＯｅ以上、（
ＢＨ）ｍａｘが４５ＭＧＯｅ以上と従来の高性能希土類
コバルト磁石と比較しても、格段に高い高性能を発揮す
る。また、用途に応じ、選定された種々の磁石特性を発
揮するよう、種々組成のＦｅ−Ｂ−Ｒ系永久磁石が提案
されている。[Prior art] Today, F
The e-B-R permanent magnet (Japanese Unexamined Patent Publication No. 59-46008) exhibits high magnetic properties with a structure having a main phase of a ternary tetragonal compound and an R-rich phase, and has an iHc of 25 kOe or more (
BH) max is 45MGOe or more, demonstrating much higher performance than conventional high-performance rare earth cobalt magnets. Further, Fe-BR permanent magnets with various compositions have been proposed so as to exhibit various magnetic properties selected depending on the application.
【０００３】しかしながら、上記のすぐれた磁気特性を
有するＦｅ−Ｂ−Ｒ系永久磁石は主成分として、空気中
で酸化あるいは水酸化し次第に酸化物あるいは水酸化物
を生成し易い希土類元素及び鉄を含有するため、Ｆｅ−
Ｂ−Ｒ系永久磁石を磁気回路に組込んだ場合に磁石表面
に生成する酸化物あるいは水酸化物により、磁気回路の
出力低下及び磁気回路間の磁性のばらつきを惹起し、ま
た、表面に生成した酸化物の脱落による周辺機器への汚
染の問題があった。However, Fe-B-R permanent magnets having the above-mentioned excellent magnetic properties mainly contain rare earth elements and iron, which easily form oxides or hydroxides when oxidized or hydroxylated in the air. Because it contains Fe-
When a B-R permanent magnet is incorporated into a magnetic circuit, oxides or hydroxides generated on the magnet surface cause a decrease in the output of the magnetic circuit and variations in magnetism between magnetic circuits. There was a problem of contamination of peripheral equipment due to falling oxides.
【０００４】そこで、上記のＦｅ−Ｂ−Ｒ系永久磁石の
耐食性の改善のため、磁石体表面に無電解めっき法ある
いは電解めっき法により耐食性金属めっき層を被覆した
り、耐食性樹脂を浸漬法や塗布法にてコーティングした
り、気相成膜法にてＡｌ等の耐食性金属、合金被膜を形
成したり、耐食性金属薄片を含む樹脂層を被着形成した
り、異種の耐食性被膜を積層形成するなどの耐食性被膜
を設ける技術が提案された。[0004] Therefore, in order to improve the corrosion resistance of the above-mentioned Fe-B-R permanent magnet, the surface of the magnet body is coated with a corrosion-resistant metal plating layer by electroless plating or electrolytic plating, or a corrosion-resistant resin is coated by dipping or electroplating. Coating with a coating method, forming a corrosion-resistant metal or alloy film such as Al using a vapor deposition method, depositing a resin layer containing corrosion-resistant metal flakes, or layering different types of corrosion-resistant films. Techniques for applying corrosion-resistant coatings have been proposed.
【０００５】[0005]
【発明が解決しようとする課題】無電解めっき法あるい
は電解めっき法は、酸性あるいはアルカリ性溶液中で処
理する為、磁石表面が腐食され磁気特性の劣化およびば
らつきを生じるばかりでなく、めっき被膜にピンホール
が存在するため、塩水噴霧テストなどの過酷な試験に対
しては十分な耐食性が得られない。[Problems to be Solved by the Invention] Since electroless plating or electrolytic plating is processed in an acidic or alkaline solution, the magnet surface not only corrodes, causing deterioration and variation in magnetic properties, but also causes pins to form on the plating film. Due to the presence of holes, sufficient corrosion resistance cannot be obtained for severe tests such as salt spray tests.
【０００６】一方、耐食性樹脂を浸漬法や塗布法あるい
は電着法でコーティングした場合、ピンホールは存在し
ないが、樹脂被膜の透水率が金属被膜と比較して大きい
ため十分な耐食性が得られない問題があった。On the other hand, when a corrosion-resistant resin is coated by a dipping method, a coating method, or an electrodeposition method, there are no pinholes, but sufficient corrosion resistance cannot be obtained because the water permeability of the resin film is higher than that of a metal film. There was a problem.
【０００７】この発明は、Ｆｅ−Ｂ−Ｒ系永久磁石の耐
食性の向上を目的とし、特に樹脂塗装を施したＦｅ−Ｂ
−Ｒ系永久磁石の耐食性を向上させるだけでなく、樹脂
塗装被膜の薄膜化を行い表面処理時間などの削減が可能
な耐食性Ｆｅ−Ｂ−Ｒ系永久磁石の提供を目的としてい
る。The purpose of this invention is to improve the corrosion resistance of Fe-B-R permanent magnets, and in particular to improve the corrosion resistance of Fe-B-R permanent magnets.
The object of the present invention is to provide a corrosion-resistant Fe-BR-based permanent magnet that not only improves the corrosion resistance of the -R-based permanent magnet but also allows the reduction of surface treatment time by making the resin coating film thinner.
【０００８】[0008]
【課題を解決するための手段】この発明は、Ｒ１０〜３
０原子％、Ｂ２〜２８原子％、Ｆｅ６５〜８０原子％を
主成分として主相が正方晶相からなり、磁石体表面に露
出する正方晶相の表層にα−Ｆｅ、その外側にＦｅＯ、
Ｆｅ３Ｏ４、最外層にα−Ｆｅ２Ｏ３が形成され、露出
する正方晶の粒界相はＲ２Ｏ３（Ｈｅｘａｇｏｎａｌ）
相からなる厚さ１〜２０μｍの表面層を有することを特
徴とする耐食性永久磁石である。[Means for Solving the Problems] This invention provides R10-3
The main phase consists of a tetragonal phase with 0 at%, B2 to 28 at%, and Fe65 to 80 at% as main components, α-Fe in the surface layer of the tetragonal phase exposed on the surface of the magnet, FeO on the outside,
Fe3O4, α-Fe2O3 is formed in the outermost layer, and the exposed tetragonal grain boundary phase is R2O3 (Hexagonal)
The present invention is a corrosion-resistant permanent magnet characterized by having a surface layer consisting of a phase with a thickness of 1 to 20 μm.
【０００９】また、この発明は、Ｒ１０〜３０原子％、
Ｂ２〜２８原子％、Ｆｅ６５〜８０原子％を主成分とす
るＦｅ−Ｂ−Ｒ系永久磁石の製造方法において、磁石体
の研削加工後、真空中あるいは不活性ガス中で時効処理
した後、大気中あるいは酸素濃度０．１ｖｏｌ％以上の
酸化性雰囲気中で２００〜３５０℃にて１５分〜１２時
間熱処理することを特徴とする耐食性永久磁石の製造方
法である。[0009] Furthermore, the present invention provides R10 to 30 atomic %,
In the method for manufacturing Fe-B-R permanent magnets whose main components are 2 to 28 at% of B and 65 to 80 at% of Fe, after grinding the magnet body and aging treatment in vacuum or inert gas, This is a method for producing a corrosion-resistant permanent magnet, which is characterized by heat treatment at 200 to 350° C. for 15 minutes to 12 hours in an oxidizing atmosphere with an oxygen concentration of 0.1 vol % or more.
【００１０】0010
【作用】この発明は、Ｆｅ−Ｂ−Ｒ系永久磁石の耐食性
ならびに表面処理後の耐食性を向上させることを目的に
種々検討した結果、得られた磁石体を研削加工したのち
、真空中あるいは不活性雰囲気中で時効処理を行った後
、大気中あるいは酸素濃度０．１ｖｏｌ％以上の酸化性
雰囲気中で熱処理することにより、磁石体表面に露出す
る正方晶相の表層にα−Ｆｅ、その外側にＦｅＯ、Ｆｅ
３Ｏ４、最外層にα−Ｆｅ２Ｏ３が形成され、露出する
正方晶の粒界相がＲ２Ｏ３（Ｈｅｘａｇｏｎａｌ）に変
化し磁石表面が不動態化され、磁石体自体の耐食性が向
上するだけでなく、耐酸化性樹脂を表面処理した後の耐
食性も向上することを知見し、この発明を完成したもの
である。[Operation] As a result of various studies aimed at improving the corrosion resistance of Fe-B-R permanent magnets as well as the corrosion resistance after surface treatment, the present invention was developed by grinding the obtained magnet body and then grinding it in a vacuum or in a free environment. After aging treatment in an active atmosphere, heat treatment is performed in the air or in an oxidizing atmosphere with an oxygen concentration of 0.1 vol% or more, so that α-Fe is added to the surface layer of the tetragonal phase exposed on the surface of the magnet, and the outside thereof is FeO, Fe
3O4, α-Fe2O3 is formed in the outermost layer, and the exposed tetragonal grain boundary phase changes to R2O3 (Hexagonal), making the magnet surface passivated, which not only improves the corrosion resistance of the magnet itself, but also improves oxidation resistance. This invention was completed based on the discovery that the corrosion resistance of a plastic resin is also improved after surface treatment.
【００１１】この発明によるＦｅ−Ｂ−Ｒ系永久磁石は
、主相が正方晶相からなり、熱処理により磁石体表面に
露出する正方晶相の表層にα−Ｆｅ、その外側にＦｅＯ
、Ｆｅ３Ｏ４、最外層にα−Ｆｅ２Ｏ３を形成し、露出
する正方晶の粒界相をＲ２Ｏ３（Ｈｅｘａｇｏｎａｌ）
相となしたことを特徴とするが、表面に露出する正方晶
の表層に設ける特定の４層及び露出する正方晶の粒界相
の総厚みは、耐食性の向上効果を得るために少なくとも
１μｍ以上の厚みが必要である。また、α−Ｆｅ、Ｆｅ
Ｏ、Ｆｅ３Ｏ４、α−Ｆｅ２Ｏ３の厚みは１〜１０μｍ
厚みが好ましく、粒界相に生成させるＲ２Ｏ３（Ｈｅｘ
ａｇｏｎａｌ）相の厚みは１〜２０μｍ厚みが好ましい
。磁石体表面の表面層の厚みを１〜２０μｍに限定した
理由は、１μｍ未満では耐食性の向上効果が不十分であ
り、２０μｍを越えると表面層の磁性が失われ磁気特性
が劣化するためである。[0011] In the Fe-B-R permanent magnet according to the present invention, the main phase is a tetragonal phase, and α-Fe is formed on the surface layer of the tetragonal phase exposed on the surface of the magnet body by heat treatment, and FeO is formed on the outside thereof.
, Fe3O4, α-Fe2O3 is formed in the outermost layer, and the exposed tetragonal grain boundary phase is R2O3 (Hexagonal).
However, the total thickness of the specific four layers provided on the surface layer of the tetragonal crystal exposed on the surface and the grain boundary phase of the exposed tetragonal crystal is at least 1 μm or more in order to obtain the effect of improving corrosion resistance. thickness is required. Also, α-Fe, Fe
The thickness of O, Fe3O4, α-Fe2O3 is 1 to 10 μm
The thickness is preferable, and R2O3 (Hex
The thickness of the agonal) phase is preferably 1 to 20 μm. The reason why the thickness of the surface layer on the surface of the magnet is limited to 1 to 20 μm is that if it is less than 1 μm, the effect of improving corrosion resistance will be insufficient, and if it exceeds 20 μm, the surface layer will lose its magnetism and the magnetic properties will deteriorate. .
【００１２】組成限定理由
Ｒは、Ｆｅ−Ｂ−Ｒ系永久磁石における必須元素であっ
て、１０原子％未満では高磁気特性、特に高保磁力が得
られず、３０原子％を越えるとＲリッチな非磁性相が多
くなり、残留磁束密度 （Ｂｒ）が低下して、すぐれ
た特性の永久磁石が得られず、Ｒは１０原子％〜３０原
子％の範囲とする。またＲは、Ｎｄ、Ｐｒ、Ｄｙ、Ｈｏ
、Ｔｂのうち少なくとも１種、あるいはさらにＬａ、Ｃ
ｅ、Ｓｍ、Ｇｄ、Ｅｒ、Ｅｕ、Ｔｍ、Ｙｂ、Ｌｕ、Ｙの
うち少なくとも１種を含むものが好ましい。Reason for composition limitation R is an essential element in Fe-B-R permanent magnets, and if it is less than 10 atomic %, high magnetic properties, especially high coercive force, cannot be obtained, and if it exceeds 30 atomic %, it is R-rich. Since the nonmagnetic phase increases, the residual magnetic flux density (Br) decreases, and a permanent magnet with excellent characteristics cannot be obtained, so R is set in the range of 10 at % to 30 at %. Further, R is Nd, Pr, Dy, Ho
, at least one of Tb, or further La, C
Those containing at least one of e, Sm, Gd, Er, Eu, Tm, Yb, Lu, and Y are preferable.
【００１３】Ｂは、該系永久磁石における必須元素であ
って、 ２原子％未満では、菱面体構造が主相となり
高い保磁力（ｉＨｃ）は得られず、２８原子％を越える
とＢリッチな非磁性相が多くなり残留磁束密度 （Ｂ
ｒ）が低下するため、すぐれた永久磁石が得られず、Ｂ
は２原子％〜２８原子％の範囲とする。[0013] B is an essential element in the system permanent magnet, and if it is less than 2 atomic %, the rhombohedral structure becomes the main phase and high coercive force (iHc) cannot be obtained, and if it exceeds 28 atomic %, B-rich As the non-magnetic phase increases, the residual magnetic flux density (B
r) decreases, an excellent permanent magnet cannot be obtained, and B
is in the range of 2 atomic % to 28 atomic %.
【００１４】Ｆｅ は、該系永久磁石における必須元
素であって、６５原子％未満では残留磁束密度 （Ｂ
ｒ）が低下し、８０原子％を越えると高い保磁力が得ら
れないので、Ｆｅ は６５原子％〜８０原子％の含有
とする。さらに、Ｆｅの一部をＣｏで置換したり、特性
の改善のため種々の添加元素を含有させることができる
。[0014] Fe is an essential element in the permanent magnet, and if it is less than 65 atomic %, the residual magnetic flux density (B
If r) decreases and exceeds 80 atom %, high coercive force cannot be obtained, so Fe is contained in an amount of 65 atom % to 80 atom %. Furthermore, a part of Fe can be replaced with Co, or various additive elements can be included to improve the characteristics.
【００１５】製造方法
この発明の特徴である特定組成、組織からなる磁石体表
面層の形成方法として、焼結永久磁石の場合、工業的生
産には以下の熱処理方法が好ましい。成形体を真空中あ
るいは不活性雰囲気中にて焼結した後、切断、研削等の
加工工程を施した後、真空中あるいは不活性ガス中で時
効処理を行い、さらに大気中あるいは少なくとも酸素濃
度が０．１ｖｏｌ％以上の酸化性雰囲気中で熱処理する
。Manufacturing Method In the case of a sintered permanent magnet, the following heat treatment method is preferred for industrial production as a method for forming a surface layer of a magnet body having a specific composition and structure, which is a feature of the present invention. After the compact is sintered in a vacuum or in an inert atmosphere, it is subjected to processing steps such as cutting and grinding, and then aged in a vacuum or in an inert gas, and then in the atmosphere or at least at a low oxygen concentration. Heat treatment is performed in an oxidizing atmosphere of 0.1 vol% or more.
【００１６】該系永久磁石成形体を４５０〜７００℃で
１５分以上保持する時効処理により、表面に露出する正
方晶相の表層にα−Ｆｅ、その外側にＦｅＯ、Ｆｅ３Ｏ
４、最外層にα−Ｆｅ２Ｏ３が形成され、露出する正方
晶の粒界相はＲ２Ｏ３（Ｈｅｘａｇｏｎａｌ）相に変化
するが、該表面層厚みが１μｍ未満と薄く十分な耐食性
が得られない。また、時効処理を長時間実施することに
より該表面層を１μｍ厚み以上にすることができるが、
工業生産では長時間の時効処理は実用的ではなく、磁石
特性を劣化させるため、４５０〜７００℃、１５分〜５
時間の時効処理したのち、後述の酸化性雰囲気中の熱処
理を施すことにより、磁石特性を劣化させることなく該
表面層厚みを１〜２０μｍにできる。[0016] By aging the permanent magnet molded body at 450 to 700°C for 15 minutes or more, α-Fe is formed on the surface layer of the tetragonal phase exposed on the surface, and FeO and Fe3O are formed on the outside.
4. α-Fe2O3 is formed in the outermost layer, and the exposed tetragonal grain boundary phase changes to R2O3 (Hexagonal) phase, but the surface layer is thin, less than 1 μm, and sufficient corrosion resistance cannot be obtained. In addition, by carrying out aging treatment for a long time, the surface layer can be made thicker than 1 μm,
In industrial production, long-term aging treatment is not practical and deteriorates magnetic properties, so aging treatment at 450 to 700°C for 15 minutes to 5
After the aging treatment, the surface layer can be made to have a thickness of 1 to 20 μm without deteriorating the magnetic properties by performing a heat treatment in an oxidizing atmosphere as described below.
【００１７】酸化性雰囲気中の熱処理は、大気中あるい
は少なくとも酸素濃度が０．１ｖｏｌ％以上の酸化性雰
囲気中で行うもので、処理温度が２００℃未満ではα−
Ｆｅ、ＦｅＯ、Ｆｅ３Ｏ４、α−Ｆｅ２Ｏ３及びＲ２Ｏ
３（Ｈｅｘａｇｏｎａｌ）相の厚みを１μｍ以上とする
のに長時間を要して効率が悪く、また、処理温度が３５
０℃を越えると酸化が急激に進行し、内部への酸素拡散
が増加して磁石特性が劣化するだけでなく、表面層が脆
くなり好ましくないため、２００〜３５０℃の範囲とす
る。より好ましい処理温度は２５０〜３００℃である。The heat treatment in an oxidizing atmosphere is carried out in the air or in an oxidizing atmosphere with an oxygen concentration of at least 0.1 vol% or more, and if the treatment temperature is less than 200°C, α-
Fe, FeO, Fe3O4, α-Fe2O3 and R2O
It takes a long time to make the thickness of the 3 (Hexagonal) phase 1 μm or more, which is inefficient, and the processing temperature is 35 μm or more.
If the temperature exceeds 0°C, oxidation will rapidly proceed, oxygen diffusion into the interior will increase, and the magnetic properties will deteriorate, as well as the surface layer will become brittle, which is undesirable. A more preferable treatment temperature is 250 to 300°C.
【００１８】酸化性雰囲気中の熱処理時間は、１５分未
満ではα−Ｆｅ、ＦｅＯ、Ｆｅ３Ｏ４、α−Ｆｅ２Ｏ３
及びＲ２Ｏ３（Ｈｅｘａｇｏｎａｌ）相の厚みを１μｍ
以上とすることができず、１２時間を越えると酸化が進
行しすぎて内部への酸素拡散が増加し、磁石特性が劣化
するだけでなく、表面層が脆くなり好ましくないため、
１５分〜１２時間の範囲とする。より好ましい処理時間
は１〜８時間である。If the heat treatment time in an oxidizing atmosphere is less than 15 minutes, α-Fe, FeO, Fe3O4, α-Fe2O3
and the thickness of the R2O3 (Hexagonal) phase is 1 μm.
If it exceeds 12 hours, oxidation will progress too much and oxygen diffusion into the interior will increase, which will not only deteriorate the magnetic properties but also make the surface layer brittle, which is undesirable.
The duration is from 15 minutes to 12 hours. A more preferred treatment time is 1 to 8 hours.
【００１９】この発明によりＦｅ−Ｂ−Ｒ磁石の耐食性
に著しく向上するが、さらに浸漬法、スプレー法、電着
法等により、耐酸化性樹脂を被着させるとなお一層耐食
性が向上する。この発明において、浸漬法、スプレー法
により被着する樹脂としては、エポキシ樹脂、ウレタン
樹脂、弗素樹脂、フラン樹脂、ポリシロキサン樹脂等が
好ましく、電着法により被着する樹脂としては、エポキ
シ樹脂、アクリル樹脂等が好ましい。The present invention significantly improves the corrosion resistance of Fe-B-R magnets, but the corrosion resistance is further improved when an oxidation-resistant resin is applied by a dipping method, a spray method, an electrodeposition method, or the like. In this invention, the resin to be deposited by dipping or spraying is preferably epoxy resin, urethane resin, fluororesin, furan resin, polysiloxane resin, etc., and the resin to be deposited by electrodeposition is preferably epoxy resin, Acrylic resin and the like are preferred.
【００２０】[0020]
【実施例】実施例１
出発原料として、純度９９．９％の電解鉄、フェロボロ
ン合金、純度９９．７％以上のＮｄ、Ｄｙ、Ｃｏを使用
してこれらを配合後、高周波溶解して鋳造し、１４Ｎｄ
−０．５Ｄｙ−７Ｂ−３Ｃｏ−残Ｆｅ（ａｔ％）なる組
成の鋳塊を得た。その後インゴットを粗粉砕、次に微粉
砕し、平均粒度３μｍの微粉末を得た。この微粉末を金
型に挿入して１２ｋＯｅの磁界中で配向し、磁界と直角
方向に１．５ｔｏｎ／ｃｍ２の圧力で成形し、１０ｃｍ
×５ｃｍ×厚み６ｍｍ寸法の成形体を得た。[Example] Example 1 Electrolytic iron with a purity of 99.9%, ferroboron alloy, and Nd, Dy, and Co with a purity of 99.7% or more were used as starting materials, and after mixing these, they were high-frequency melted and cast. , 14Nd
An ingot having a composition of -0.5Dy-7B-3Co-remaining Fe (at%) was obtained. Thereafter, the ingot was coarsely ground and then finely ground to obtain a fine powder with an average particle size of 3 μm. This fine powder was inserted into a mold, oriented in a magnetic field of 12 kOe, and molded at a pressure of 1.5 ton/cm2 in a direction perpendicular to the magnetic field.
A molded article with dimensions of 5 cm x 6 mm in thickness was obtained.
【００２１】得られた成形体を１１００℃、３時間、Ａ
ｒ雰囲気中の条件で焼結し、冷却後にダイヤモンド砥石
で７ｃｍ×３．５ｃｍ×厚み４ｍｍ寸法の磁石体に研削
した後、溶剤にて洗浄し乾燥させた後、真空中、５３０
℃×２時間の時効処理を施した。その後大気中、２５０
℃×２時間の酸化性雰囲気中熱処理を施してこの発明の
永久磁石を作製した。なお、得られた永久磁石表面に露
出している正方晶表面に生成されたα−Ｆｅ、ＦｅＯ、
Ｆｅ３Ｏ４、α−Ｆｅ２Ｏ３の厚みは５μｍで、Ｒ２Ｏ
３（Ｈｅｘａｇｏｎａｌ）相の厚みは１０μｍであった
。[0021] The obtained molded body was heated at 1100°C for 3 hours.
After sintering under the conditions of r atmosphere, after cooling, it was ground into a magnet body with dimensions of 7 cm x 3.5 cm x thickness 4 mm using a diamond grindstone, washed with a solvent, dried, and then heated in a vacuum at 530 mm.
Aging treatment was performed at ℃ for 2 hours. Then in the atmosphere, 250
A permanent magnet of the present invention was produced by heat treatment in an oxidizing atmosphere at ℃ for 2 hours. In addition, α-Fe, FeO,
The thickness of Fe3O4 and α-Fe2O3 is 5 μm, and R2O
The thickness of the 3 (Hexagonal) phase was 10 μm.
【００２２】得られた永久磁石体の磁石特性及び磁石体
を８０℃、相対湿度９０％の雰囲気中に１００時間放置
した後の酸化増量及び磁石特性を測定し表１に示す。ま
た磁石体表面に結露することを防止するため、予め１０
０℃に加温した後、８０℃相対湿度９０％の雰囲気に１
００時間放置したのち、純水中で超音波洗浄を施し、磁
石体表面の腐食生成物を除去し、１００℃にて乾燥した
後の重量減少量及び磁石特性を調べた結果を表２に示す
。The magnetic properties of the obtained permanent magnet, and the oxidation weight gain and magnetic properties after the magnet was left in an atmosphere of 80° C. and 90% relative humidity for 100 hours were measured and are shown in Table 1. In addition, in order to prevent dew condensation on the surface of the magnet, please
After heating to 0℃, place it in an atmosphere of 80℃ and 90% relative humidity.
After being left for 00 hours, the magnet was subjected to ultrasonic cleaning in pure water to remove corrosion products on the surface of the magnet, and after drying at 100°C, the weight loss and magnet properties were investigated. The results are shown in Table 2. .
【００２３】比較例１
この発明による酸化性雰囲気中熱処理を施さない以外は
、実施例１と全く同様方法で製造して同一組成の永久磁
石体を得た。比較磁石を８０℃、相対温度９０％の雰囲
気に１００時間放置した後の酸化増量および磁石特性の
測定結果を表１に示す、また予め１００℃に加温後、８
０℃、相対温度９０％の雰囲気に１００時間放置したの
ち、実施例１と同様の手法で測定した重量減少量および
磁石特性を表２に示す。Comparative Example 1 A permanent magnet having the same composition was obtained in exactly the same manner as in Example 1, except that the heat treatment in an oxidizing atmosphere according to the present invention was not performed. Table 1 shows the measurement results of oxidation weight gain and magnet properties after a comparative magnet was left in an atmosphere of 80°C and 90% relative temperature for 100 hours.
Table 2 shows the amount of weight loss and magnetic properties measured in the same manner as in Example 1 after being left in an atmosphere of 0° C. and 90% relative temperature for 100 hours.
【００２４】実施例２
実施例１と全く同様方法にて製造して得られたこの発明
の永久磁石体に、スプレー塗装によりエポキシ樹脂を被
着させ、焼付けをして２０μｍの樹脂層を有する磁石体
を得た。得られた磁石体を８０℃、相対温度９０％の雰
囲気に１０００時間放置した後の発錆状況を表３に示す
。Example 2 An epoxy resin was coated on a permanent magnet of the present invention produced in exactly the same manner as in Example 1 by spray painting, and baked to produce a magnet having a resin layer of 20 μm. I got a body. Table 3 shows the state of rust after the obtained magnet was left in an atmosphere of 80° C. and relative temperature of 90% for 1000 hours.
【００２５】比較例２
酸化性雰囲気中熱処理を施さない以外は、実施例１と全
く同様方法にて製造して得られた比較永久磁石体に、実
施例２と同様の塗装を施して同様の試験を行い、その発
錆状況を調べて表３に示す。Comparative Example 2 A comparative permanent magnet obtained by manufacturing in exactly the same manner as in Example 1 except that it was not heat-treated in an oxidizing atmosphere was coated with the same coating as in Example 2 to produce a similar product. A test was conducted, and the rusting conditions were investigated and are shown in Table 3.
【００２６】[0026]
【表１】[Table 1]
【００２７】[0027]
【表２】[Table 2]
【００２８】[0028]
【表３】[Table 3]
【００２９】[0029]
【発明の効果】この発明は、Ｆｅ−Ｂ−Ｒ系永久磁石体
を研削加工したのち、真空中あるいは不活性雰囲気中で
時効処理を行い、さらに、大気中あるいは酸素濃度０．
１ｖｏｌ％以上の酸化性雰囲気中で熱処理することによ
り、磁石体表面に露出する正方晶相の表層にα−Ｆｅ、
その外側にＦｅＯ、Ｆｅ３Ｏ４、最外層にα−Ｆｅ２Ｏ
３が形成され、露出する正方晶の粒界相がＲ２Ｏ３（Ｈ
ｅｘａｇｏｎａｌ）に変化し磁石表面が不動態化され、
実施例に明らかように、磁石体自体の耐食性が著しく向
上するだけでなく、耐酸化性樹脂を表面処理した後の耐
食性も向上する。さらに、Ｆｅ−Ｂ−Ｒ系永久磁石自体
の耐食性を向上させることができたため、樹脂塗装被膜
の厚みを薄くでき、塗装処理時間の短縮及び表面処理コ
ストの低減ができる。Effects of the Invention According to the present invention, after grinding a Fe-B-R permanent magnet body, aging treatment is performed in a vacuum or an inert atmosphere, and then in the atmosphere or in an oxygen concentration of 0.
By heat treatment in an oxidizing atmosphere of 1 vol% or more, α-Fe,
FeO, Fe3O4 on the outside, α-Fe2O on the outermost layer
3 is formed, and the exposed tetragonal grain boundary phase is R2O3(H
exagonal) and the magnet surface becomes passivated,
As is clear from the examples, not only the corrosion resistance of the magnet body itself is significantly improved, but also the corrosion resistance after the surface treatment with the oxidation-resistant resin is improved. Furthermore, since the corrosion resistance of the Fe-BR-based permanent magnet itself can be improved, the thickness of the resin coating film can be reduced, and the coating treatment time and surface treatment cost can be reduced.
Claims (3)
％、Ｆｅ６５〜８０原子％を主成分として主相が正方晶
相からなり、磁石体表面に露出する正方晶相の表層にα
−Ｆｅ、その外側にＦｅＯ、Ｆｅ３Ｏ４、最外層にα−
Ｆｅ２Ｏ３が形成され、露出する正方晶の粒界相はＲ２
Ｏ３（Ｈｅｘａｇｏｎａｌ）相からなる厚さ１〜２０μ
ｍの表面層を有することを特徴とする耐食性永久磁石。Claim 1: The main phase consists of a tetragonal phase with R10 to 30 at%, B2 to 28 at%, and Fe 65 to 80 at% as main components, and the surface layer of the tetragonal phase exposed on the surface of the magnet has α
-Fe, FeO on the outside, Fe3O4, α- on the outermost layer
Fe2O3 is formed and the exposed tetragonal grain boundary phase is R2
Consisting of O3 (Hexagonal) phase, thickness 1-20μ
A corrosion-resistant permanent magnet characterized by having a surface layer of m.
ことを特徴とする請求項１記載の耐食性永久磁石。2. The corrosion-resistant permanent magnet according to claim 1, further comprising an oxidation-resistant resin layer on the surface of the magnet body.
％、Ｆｅ６５〜８０原子％を主成分とするＦｅ−Ｂ−Ｒ
系永久磁石の製造方法において、磁石体の研削加工後、
真空中あるおは不活性ガス中で時効処理した後、大気中
あるいは酸素濃度０．１ｖｏｌ％以上の酸化性雰囲気中
で２００〜３５０℃にて１５分〜１２時間熱処理するこ
とを特徴とする耐食性永久磁石の製造方法。3. Fe-B-R whose main components are 10 to 30 atomic % of R, 2 to 28 atomic % of B, and 65 to 80 atomic % of Fe.
In the method for manufacturing permanent magnets, after grinding the magnet body,
Corrosion resistance characterized by aging treatment in vacuum or in an inert gas, followed by heat treatment at 200 to 350°C for 15 minutes to 12 hours in the air or in an oxidizing atmosphere with an oxygen concentration of 0.1 vol% or more. A method of manufacturing permanent magnets.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3124870A JP2844269B2 (en) | 1991-04-26 | 1991-04-26 | Corrosion resistant permanent magnet and method for producing the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3124870A JP2844269B2 (en) | 1991-04-26 | 1991-04-26 | Corrosion resistant permanent magnet and method for producing the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04328804A true JPH04328804A (en) | 1992-11-17 |
| JP2844269B2 JP2844269B2 (en) | 1999-01-06 |
Family
ID=14896140
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3124870A Expired - Lifetime JP2844269B2 (en) | 1991-04-26 | 1991-04-26 | Corrosion resistant permanent magnet and method for producing the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2844269B2 (en) |
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