JP3623564B2 - Anisotropic bonded magnet - Google Patents
Anisotropic bonded magnet Download PDFInfo
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- JP3623564B2 JP3623564B2 JP29206095A JP29206095A JP3623564B2 JP 3623564 B2 JP3623564 B2 JP 3623564B2 JP 29206095 A JP29206095 A JP 29206095A JP 29206095 A JP29206095 A JP 29206095A JP 3623564 B2 JP3623564 B2 JP 3623564B2
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- 239000000843 powder Substances 0.000 claims description 87
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 34
- 239000002114 nanocomposite Substances 0.000 claims description 19
- 239000000203 mixture Substances 0.000 claims description 12
- 239000013078 crystal Substances 0.000 claims description 11
- 229920005989 resin Polymers 0.000 claims description 10
- 239000011347 resin Substances 0.000 claims description 10
- 239000002245 particle Substances 0.000 claims description 9
- 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 description 7
- 229910052742 iron Inorganic materials 0.000 claims description 6
- 229910052779 Neodymium Inorganic materials 0.000 claims description 4
- 229910052777 Praseodymium Inorganic materials 0.000 claims description 4
- 229910052782 aluminium Inorganic materials 0.000 claims description 4
- ZDVYABSQRRRIOJ-UHFFFAOYSA-N boron;iron Chemical compound [Fe]#B ZDVYABSQRRRIOJ-UHFFFAOYSA-N 0.000 claims description 4
- 229910052804 chromium Inorganic materials 0.000 claims description 4
- 229910052802 copper Inorganic materials 0.000 claims description 4
- 229910052750 molybdenum Inorganic materials 0.000 claims description 4
- 229910052710 silicon Inorganic materials 0.000 claims description 4
- 229910052720 vanadium Inorganic materials 0.000 claims description 4
- 229910052737 gold Inorganic materials 0.000 claims description 3
- 229910052697 platinum Inorganic materials 0.000 claims description 3
- 230000004907 flux Effects 0.000 description 10
- 239000011230 binding agent Substances 0.000 description 9
- 238000010438 heat treatment Methods 0.000 description 9
- 238000000465 moulding Methods 0.000 description 9
- 230000000694 effects Effects 0.000 description 8
- 230000007423 decrease Effects 0.000 description 7
- 238000000034 method Methods 0.000 description 7
- 238000002156 mixing Methods 0.000 description 7
- 238000010298 pulverizing process Methods 0.000 description 7
- 229910045601 alloy Inorganic materials 0.000 description 6
- 239000000956 alloy Substances 0.000 description 6
- 239000010949 copper Substances 0.000 description 4
- 238000005336 cracking Methods 0.000 description 4
- 230000006872 improvement Effects 0.000 description 4
- 239000006247 magnetic powder Substances 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 238000006467 substitution reaction Methods 0.000 description 4
- 229910000521 B alloy Inorganic materials 0.000 description 3
- 230000005347 demagnetization Effects 0.000 description 3
- 230000005415 magnetization Effects 0.000 description 3
- 229910052761 rare earth metal Inorganic materials 0.000 description 3
- 229910052684 Cerium Inorganic materials 0.000 description 2
- 229910052692 Dysprosium Inorganic materials 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 239000003822 epoxy resin Substances 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 229910052746 lanthanum Inorganic materials 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 229920000647 polyepoxide Polymers 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 238000010791 quenching Methods 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 229910052709 silver Inorganic materials 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 230000035882 stress Effects 0.000 description 2
- 229910000859 α-Fe Inorganic materials 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 229910052691 Erbium Inorganic materials 0.000 description 1
- 229910052693 Europium Inorganic materials 0.000 description 1
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 1
- 229910052688 Gadolinium Inorganic materials 0.000 description 1
- 229910052689 Holmium Inorganic materials 0.000 description 1
- 229910052765 Lutetium Inorganic materials 0.000 description 1
- 229910001122 Mischmetal Inorganic materials 0.000 description 1
- 229910052772 Samarium Inorganic materials 0.000 description 1
- 229910052771 Terbium Inorganic materials 0.000 description 1
- 229910052775 Thulium Inorganic materials 0.000 description 1
- 229910052769 Ytterbium Inorganic materials 0.000 description 1
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- JZQOJFLIJNRDHK-CMDGGOBGSA-N alpha-irone Chemical compound CC1CC=C(C)C(\C=C\C(C)=O)C1(C)C JZQOJFLIJNRDHK-CMDGGOBGSA-N 0.000 description 1
- 229910052787 antimony Inorganic materials 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000011362 coarse particle Substances 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000000748 compression moulding Methods 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 229910052733 gallium Inorganic materials 0.000 description 1
- 229910052732 germanium Inorganic materials 0.000 description 1
- 229910052735 hafnium Inorganic materials 0.000 description 1
- 238000000265 homogenisation Methods 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000000696 magnetic material Substances 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000002074 melt spinning Methods 0.000 description 1
- 239000005300 metallic glass Substances 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 238000005121 nitriding Methods 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 238000007712 rapid solidification Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 230000002195 synergetic effect Effects 0.000 description 1
- 229910052715 tantalum Inorganic materials 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 229920005992 thermoplastic resin Polymers 0.000 description 1
- 229920001187 thermosetting polymer Polymers 0.000 description 1
- 229910052718 tin Inorganic materials 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 229910052727 yttrium Inorganic materials 0.000 description 1
- 229910052725 zinc 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
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
- H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
- H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
- H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
- H01F1/047—Alloys characterised by their composition
- H01F1/053—Alloys characterised by their composition containing rare earth metals
- H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
- H01F1/057—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B
- H01F1/0571—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes
- H01F1/0575—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together
- H01F1/0578—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together bonded together
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
- H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
- H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
- H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
- H01F1/047—Alloys characterised by their composition
- H01F1/053—Alloys characterised by their composition containing rare earth metals
- H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
- H01F1/057—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B
- H01F1/0571—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes
- H01F1/0573—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes obtained by reduction or by hydrogen decrepitation or embrittlement
Landscapes
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Hard Magnetic Materials (AREA)
Description
【０００１】
【発明の属する技術分野】
この発明は、耐熱性、耐候性と共に磁気特性、特に残留磁束密度（以下Ｂｒという）、最大磁気エネルギー積（以下（ＢＨ）ｍａｘという）のすぐれた異方性ボンド磁石に係り、Ｒ−Ｆｅ−Ｂ系合金鋳塊あるいは前記鋳塊を粉砕して得られた粗粉砕粉を特定の熱処理条件のＨ２処理法により、特定の平均再結晶粒径を有する正方晶のＲ２Ｆｅ１４Ｂ相の再結晶粒集合組織を有する異方性磁石粉末となし、これに特定量の微細な等方性Ｒ−Ｆｅ−Ｂ系ナノコンポジット磁石粉末およびバインダーの樹脂を配合混合後、成形して得られた耐熱性、耐候性並びにＢｒ、（ＢＨ）ｍａｘ等の磁気特性のすぐれた異方性ボンド磁石に関する。
【０００２】
【従来の技術】
一般にボンド磁石は焼結磁石に比して、磁気特性では劣るにもかかわらず、機械的強度にすぐれ、且つ形状の自由度が高いこと等より、近年、その利用範囲が急速に拡大している。かかるボンド磁石は、磁石粉末と有機バインダー、金属バインダー等により結合して成形されるが、ボンド磁石の磁気特性は使用する磁石粉末の磁気特性に左右される。
【０００３】
ボンド磁石用磁石粉末としては、（１）Ｒ−Ｆｅ−Ｂ系鋳塊を機械的粉砕法、あるいはＨ２吸蔵崩壊法により得られた磁石粉末や、あるいは、（２）液体急冷法やアトマイズ法によって、溶融合金から超急冷して得られた磁石粉末が利用されている。
【０００４】
前者の（１）磁石粉末では、Ｒ２Ｆｅ１４Ｂ相が粒内破壊して粉砕されるので、Ｒ２Ｆｅ１４Ｂ相がＲリッチ相で囲まれた組織にならず、Ｒ２Ｆｅ１４Ｂ相の一部にＲリッチ相が一部付着した組織となり、また、粉砕時に磁石粉末に歪が残留するため、粉砕のままでは保磁力ｉＨｃは３ｋＯｅ以下に低下し、歪取り熱処理した磁石粉末やＲ２Ｆｅ１４Ｂ相粒界部にＲリッチ相を形成させる集合粉末とした磁石粉末でも、ボンド磁石用粉末として使用した場合、成形圧力の増加に伴って、ボンド磁石のｉＨｃは大幅に低下し、また、バインダーの硬化時にも磁気特性が低下する欠点がある。
【０００５】
一方、後者の（２）磁石粉末の場合は、個々のＲ２Ｆｅ１４Ｂ相の結晶粒の結晶方向が任意で粉末の磁気特性が等方性であるため、ボンド磁石自体も等方性であるため、高磁気特性が望めず、実用的には用途が制限される問題がある。
【０００６】
また、低価格かつ、高性能なボンド磁石を得るためにフェライト磁石粉末に高性能のＲ−Ｆｅ−Ｂ系磁石粉末を添加配合した高性能ボンド磁石が提案されているが、前記Ｒ−Ｆｅ−Ｂ系磁石粉末は超急冷粉、あるいは鋳塊粉砕粉の等方性の磁石粉末であり、磁気特性の改善向上は小さかった（特開昭６１−２８４９０６号、特開昭６３−２８７００３号、特開平２−７８２０４号、特開平３−１８１１０４号、特開平３−２２２３０３号）。
【０００７】
【発明が解決しようとする課題】
そこで、最近、異方性ボンド用磁石粉末として、Ｒ−Ｆｅ−Ｂ系合金鋳塊あるいは粉砕後の粗粉砕粉を特定の熱処理条件のＨ２処理法により、Ｒ２Ｆｅ１４Ｂ正方晶相からなる再結晶集合組織となした異方性Ｒ−Ｆｅ−Ｂ系磁石粉末が提案されている（特開平１−１３２１０６号）。
【０００８】
前記異方性磁石粉末を用いて異方性ボンド磁石を製造する方法としては、前記磁石粉末にバインダーとして樹脂を添加配合後、圧縮成形し、さらにバインダー硬化のためのキュア熱処理する工程などが一般に知られている。
【０００９】
しかし、原料粉末の異方性磁石粉末は非常に酸化され易い上、予め磁石粉末をカップリング処理等で粉末表面を被覆しても、成形時の応力によって磁石粉末には割れが発生し、活性な金属面が露出してより酸化され易くなり、また、成形したボンド磁石は密度が低くて空孔部が多く、前記空孔部にＯ２、Ｈ２Ｏが容易に侵入してボンド磁石が酸化し、磁気特性が時間とともに劣化する問題があった。
さらに成形時に磁石粉末が割れることは、磁石粉末へ多量の歪を導入することを意味し、保磁力および角型性の劣化を生じる観点からも好ましくなかった。
【００１０】
最近、異方性磁石粉末にＳｍ−Ｆｅ−Ｎ系磁石粉末を添加して、充填密度を高めた異方性ボンド磁石が提案（特開平６−１３２１０７号）されているが、前記磁石は初期磁気特性を向上させるものの、Ｓｍ−Ｆｅ−Ｎ系磁石粉末自身の耐候性の劣化から、磁気特性の劣化が大きいという問題がある。
【００１１】
この発明は、上述の異方性ボンド磁石の問題点を解消し、成形時に磁石粉末に割れを生ずることなく、耐候性と共に磁気特性、特にＢｒ、（ＢＨ）ｍａｘのすぐれた異方性ボンド磁石の提供を目的としている。
【００１２】
【課題を解決するための手段】
発明者らは、従来の異方性ボンド磁石の問題点を解決すべく、種々検討した結果、ボンド磁石中の空孔部がその耐熱性、耐候性に影響を及ぼすと考え、さらに検討した結果、異方性Ｒ−Ｆｅ−Ｂ系磁石粉末に特定量の等方性Ｒ−Ｆｅ−Ｂ系ナノコンポジット磁石粉末と樹脂を添加することにより、
▲１▼磁石空孔部に優先的に等方性Ｒ−Ｆｅ−Ｂ系ナノコンポジット磁石粉末が充填され、空孔率が減少し、磁石内部へのＯ２、Ｈ２Ｏの侵入が防止され、耐熱性、耐候性が向上すること、
▲２▼空孔部に前記等方性磁石粉末が充填されるため、磁気特性が向上すること、
▲３▼粉末の充填状態がよくなるために、成形時に異方性磁石粉末が受ける応力集中が減少し、磁石粉末の割れは減少することにより、活性の金属破面が減少し、耐熱性、耐候性が向上し、
▲４▼かかる作用効果が相乗してボンド磁石の耐熱性、耐候性の向上、および磁気特性の改善向上に有効なることを知見し、この発明を完成した。
【００１３】
すなわち、この発明は、
平均再結晶粒径が０．０５μｍ〜５０μｍのＲ２Ｆｅ１４Ｂ正方晶相からなる再結晶粒の集合組織を有する異方性Ｒ−Ｆｅ−Ｂ系磁石粉末４５ｗｔ％〜９８ｗｔ％と、平均結晶粒径５０ｎｍ以下の体心立方鉄および鉄ホウ化物を含む軟質磁性相とＮｄ２Ｆｅ１４Ｂ型結晶を有する硬質磁性相からなる等方性Ｒ−Ｆｅ−Ｂ系ナノコンポジット磁石粉末０．９ｗｔ％〜４９ｗｔ％と、樹脂１ｗｔ％〜１０ｗｔ％とからなる異方性ボンド磁石である。
【００１４】
また、この発明は、上記の異方性ボンド磁石において、
Ｒ−Ｆｅ−Ｂ系ナノコンポジット磁石粉末の組成式がＲｘ（Ｆｅ１−ｕＣｏｕ）１００−ｘ−ｙ−ｚＢｙＭｚ、（Ｒ：Ｐｒ，Ｎｄ，Ｄｙの１種または２種以上、Ｍ：Ｃｒ，Ｖ，Ｍｏ，Ａｌ，Ｓｉ，Ｃｕ，Ｇａ，Ｐｂ，Ａｕ，Ｐｔ，Ａｇの１種または２種以上）で表され、組成を限定するｘ（ａｔ％）、ｙ（ａｔ％）、ｚ（ａｔ％）及びｕが以下の範囲である異方性ボンド磁石を併せて提案する。
３≦ｘ≦６、１０≦ｙ≦３０、０＜ｚ≦１０、０＜ｕ≦０．５
【００１５】
【発明の実施の形態】
この発明において、Ｒ２Ｆｅ１４Ｂ正方晶相からなる再結晶集合組織の磁石粉末は、Ｒ−Ｆｅ−Ｂ系合金鋳塊あるいは前記鋳塊を粗粉砕して得られた粗粒を均質化処理するか、または、均質化処理せずにＨ２ガス雰囲気中で昇温し、温度７５０℃〜９５０℃に３０分〜８時間のＨ２ガス雰囲気中に保持した後、引き続いて温度７５０℃〜９５０℃に５分〜４時間の真空雰囲気中に保持した後、冷却し、粉砕して得られるものである。
【００１６】
かかる異方性Ｒ−Ｆｅ−Ｂ系磁石粉末の平均粒度を５μｍ〜５００μｍに限定した理由は、５μｍ未満では酸化し易く作業中に燃える恐れがあり、また、５００μｍを超えると磁石粉末として実用的ではないので好ましくないことにあり、好ましい平均粒度は１０μｍ〜３００μｍである。
【００１７】
また、異方性Ｒ−Ｆｅ−Ｂ系磁石粉末の平均再結晶粒径は、０．０５μｍ未満では着磁が困難となり、５０μｍを超えるとｉＨｃ（保磁力）が５ｋＯｅ以下となり、磁気特性が低下するため、０．０５μｍ〜５０μｍの範囲とし、好ましい平均再結晶粒径は０．１μｍ〜１０μｍである。
異方性磁石粉末の配合量が４５ｗｔ％未満では等方性磁石粉末の比率が多くなり、初期磁気特性が低下し、９８ｗｔ％を越えると等方性磁石粉末の添加効果、すなわち、充填率の向上による耐候性、磁気特性の向上効果が低下し、また、樹脂量の低下による磁石強度が低下するため、好ましくない。
【００１８】
この発明において、異方性磁石粉末に配合混合する等方性ナノコンポジット磁石粉末の組織は、平均結晶粒径５０ｎｍ以下の体心立方鉄および鉄ホウ化物を含む軟質磁性相とＮｄ２Ｆｅ１４Ｂ型結晶を有する硬質磁性相からなり、軟質磁性相の磁化が硬質磁性相の磁化と交換相互作用により結合して、コンポジット全体としてあたかも単一の磁性相で構成されて、従来の永久磁石のように振る舞うというものであり、一般に「交換スプリング磁石」とも呼ばれる。ナノコンポジット磁性体は溶融状態から超急冷凝固法によりいったん非晶質金属を得た後、熱処理により結晶化し、更にこれを粉砕して粉末化して得る。
【００１９】
この発明において、等方性ナノコンポジット磁石粉末の平均粒度は、異方性磁石粉末の空孔部に優先的に侵入する観点から１μｍ〜５０μｍが好ましい。
また、等方性ナノコンポジット磁石粉末の配合量は、０．９ｗｔ％未満では空孔率の低減効果が少なく、耐熱性、耐候性の改善効果や磁気特性の向上効果が得られず、また４９ｗｔ％を越えるとボンド磁石の磁気特性を劣化させるので、０．９ｗｔ％〜４９ｗｔ％とする。好ましい配合量は１ｗｔ％〜３０ｗｔ％である。
【００２０】
また、バインダーとしての樹脂の配合量は、１ｗｔ％未満ではボンド磁石の強度が十分に得られず、また１０ｗｔ％を超えると磁気特性の劣化を招来するので好ましくないため、樹脂の配合量は１ｗｔ％〜１０ｗｔ％とする。
樹脂としては、熱硬化性あるいは熱可塑性の公知の樹脂で良く、固状の樹脂は溶媒にて液状化バインダーとして使用してもよく、溶媒はボンド磁石の成形前に揮発してもよい。
【００２１】
この発明の異方性Ｒ−Ｆｅ−Ｂ系磁石粉末に用いる希土類元素Ｒは、組成の１０原子％〜３０原子％を占めるが、Ｎｄ，Ｐｒ，Ｄｙ，Ｈｏ，Ｔｂのうち少なくとも１種、あるいはさらに、Ｌａ，Ｃｅ，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。また、通常Ｒのうち１種をもって足りるが、実用上は２種以上の混合物（ミッシュメタル、シジム等）を入手上の便宜等の理由により用いることができる。なお、このＲは純希土類元素でなくてもよく、工業上入手可能な範囲で製造上不可避な不純物を含有するものでも差し支えない。
【００２２】
Ｒは、上記系磁石粉末における必須元素であって、１０原子％未満では結晶構造がα−鉄と同一構造の立方晶組織となるため、高磁気特性、特に高保磁力が得られず、３０原子％を超えると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ない。よって、Ｒは、１０原子％〜３０原子％の範囲が望ましい。
【００２３】
Ｂは、上記系磁石粉末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％を超えるとＢリッチな非磁性相が多くなり、残留磁束密度（Ｂｒ）が低下するため、すぐれた永久磁石が得られない。よって、Ｂは２原子％〜２８原子％の範囲が望ましい。
【００２４】
Ｆｅは、上記系磁石粉末において必須元素であり、６５原子％未満では残留磁束密度（Ｂｒ）が低下し、８０原子％を超えると高い保磁力が得られないので、Ｆｅは６５原子％〜８０原子％の含有が望ましい。
また、Ｆｅの一部をＣｏで置換することは、得られる磁石の磁気特性を損なうことなく、温度特性を改善することができるが、Ｃｏ置換量がＦｅの２０％を超えると、逆に磁気特性が劣化するため、好ましくない。Ｃｏの置換量がＦｅとＣｏの合計量で５原子％〜１５原子％の場合は、（Ｂｒ）は置換しない場合に比較して増加するため、高磁束密度を得るために好ましい。
【００２５】
また、Ｒ，Ｂ，Ｆｅのほか、工業的生産上不可避的不純物の存在を許容でき、例えば、Ｂの一部を４．０ｗｔ％以下のＣ、２．０ｗｔ％以下のＰ、２．０ｗｔ％以下のＳ、２．０ｗｔ％以下のＣｕのうち少なくとも１種、合計量で２．０ｗｔ％以下で置換することにより、永久磁石の製造性改善、低価格化が可能である。
【００２６】
さらに、Ａｌ，Ｔｉ，Ｖ，Ｃｒ，Ｍｎ，Ｂｉ，Ｎｂ，Ｔａ，Ｍｏ，Ｗ，Ｓｂ，Ｇｅ，Ｇａ，Ｓｎ，Ｚｒ，Ｎｉ，Ｓｉ，Ｚｎ，Ｈｆのうち少なくとも１種は、磁石粉末に対してその保磁力、減磁曲線の角型性を改善あるいは製造性の改善、低価格化に効果があるため添加することができる。なお、添加量の上限は、ボンド磁石の（ＢＨ）ｍａｘを１４ＭＧＯｅ以上とするには、（Ｂｒ）が少なくとも８ｋＧ以上必要となるため、該条件を満たす範囲が望ましい。
【００２７】
この発明において、配合混合する等方性ナノコンポジット磁石粉末の組成のＲは、Ｐｒ，Ｎｄ，Ｄｙの１種または２種以上を特定量含有のときのみ、高い磁気特性が得られ、他の希土類元素例えば、Ｃｅ，ＬａではｉＨｃが２ｋＯｅ以上の特性は得られず、重希土類元素では磁気モーメントがＮｄと逆方向に向く性質を有するため、磁化を著しく減少させる傾向があるので好ましくない。
Ｒは、３ａｔ％未満では４．０ｋＯｅ以上のｉＨｃが得られず、６ａｔ％を越えると５ｋＧ以上のＢｒが得られないので、３〜６ａｔ％とする。好ましいＲ量は３．５〜５．５ａｔ％である。
【００２８】
Ｂは、１０ａｔ％未満では超急冷法を用いても非晶質組織が得られず、熱処理しても３ｋＯｅ未満のｉＨｃしか得られず、また、３０ａｔ％を越えると５ｋＯｅ以上のｉＨｃが得られないため、１０ａｔ％〜３０ａｔ％の範囲とする。好ましい範囲は１５〜２０ａｔ％である。
【００２９】
Ｃｏは、Ｂｒ、減磁曲線の角型性および温度特性の向上に有効であるが、Ｆｅに対する置換量が５０％を越えると６ｋＧ以上のＢｒが得られないので、Ｃｏ量は０〜５０％とする。好ましい範囲は０．０１〜０．１％である。
【００３０】
Ｍは、Ｃｒ，Ｖ，Ｍｏ，Ａｌ，Ｓｉ，Ｃｕ，Ｇａ，Ｐｂ，Ａｕ，Ｐｔ，Ａｇの１種または２種以上を添加することにより、ｉＨｃの向上、Ｂｒの減磁曲線の角型性の改善向上に有効であるが、０．０１ａｔ％未満では前記効果が得られず、１０ａｔ％を越えると逆に角型性が低下するので、０．０１ａｔ％〜１０ａｔ％の添加量とする。好ましい範囲は０．０５ａｔ％〜６ａｔ％である。
【００３１】
【実施例】
実施例１
原料として真空溶解炉にて溶解鋳造し、表１に表す組成Ａ，Ｂ，Ｃを有するＲ−Ｆｅ−Ｂ系磁石用合金鋳塊を得た。これらの合金鋳塊を温度１１２０℃、時間１０時間でＡｒ雰囲気中にて均質化処理を行った。
前記鋳塊を加熱炉に挿入し、７６０ＴｏｒｒのＨ２ガスとして、加熱炉内の温度を室温から温度８５０℃に上昇し、引き続いて温度８５０℃に３時間保持した後、８５０℃に１時間保持して脱Ｈ２を行って、真空度１×１０−５Ｔｏｒｒになるまで排気冷却した。
【００３２】
その後、鋳塊をＡｒ雰囲気中で３００μｍ以下になるまで粉砕して、Ｒ−Ｆｅ−Ｂ系磁石粉末を得た。得られた磁石粉末は平均結晶粒径０．５μｍのＲ２Ｆｅ１４Ｂ正方晶相からなる再結晶粒の集合組織を有する異方性磁石粉末であった。
【００３３】
また、添加配合するＲ−Ｆｅ−Ｂ系ナノコンポジット磁石粉末は表２に表す組成ａ，ｂ，ｃの合金を溶製後、メルトスピニング装置を用いて、周速度２０ｍ／ｓで回転する銅製ロール上に径０．８ｍｍの石英ノズルより噴射して、幅２〜３ｍｍの非晶質薄帯を得た。
前記薄帯を１５℃／分の昇温速度でＡｒガス雰囲気中で加熱し、６３０℃に約５分間保持して冷却後、粉砕し、平均結晶粒径５０μｍ以下の体心立方鉄および鉄ホウ化物を含む軟質磁性相とＮｄ２Ｆｅ１４Ｂ型結晶を有する硬質磁性相からなる平均粒径３．８μｍの等方性ナノコンポジット磁石粉末を得た。
【００３４】
前記のごとく、得られた平均粒径１５０μｍの異方性磁石粉末８７ｗｔ％と、前記の平均粒径３．８μｍの等方性ナノコンポジット磁石粉末１０ｗｔ％とエポキシ樹脂３ｗｔ％を表３のごとく配合混合後、１２ｋＯｅの磁界中で、成形圧７ｔｏｎ／ｃｍ２で成形後、温度１５０℃で１時間保持して硬化し、異方性ボンド磁石を得た。
【００３５】
得られた異方性ボンド磁石の磁気特性、角型性および空孔率と耐候性試験結果を表３に表す。
また、耐熱性、耐候性試験の試験条件は大気中で１００℃×１０００時間の条件で、試験中の磁束の経時変化を測定した。なお、磁束の経時変化試験方法は試験片を着磁した後、磁束を測定し、ついで大気中にて１００℃に１０００時間放置後、再び試験片を着磁し磁束を測定し、放置前の磁束からの低下率を算出した。
【００３６】
実施例２
実施例１の表１に表す組成Ａ，Ｂ，Ｃを有するＲ−Ｆｅ−Ｂ系異方性磁石粉末と、実施例１と同一条件で製造した表２に表す組成ｄ，ｅ，ｆの等方性ナノコンポジット磁石粉末を用い、異方性磁石粉末７８ｗｔ％と、等方性ナノコンポジット磁石粉末２０ｗｔ％とエポキシ樹脂２ｗｔ％を、表３のごとく配合混合後、１２ｋＯｅの磁界中で、成形圧７ｔｏｎ／ｃｍ２で成形後、温度１５０℃で１時間保持して硬化し、異方性ボンド磁石を得た。
得られた異方性ボンド磁石の磁気特性、角型性および空孔率と耐候性試験結果を表３に表す。
【００３７】
比較例１
実施例１にて得られた磁石粉末に実施例１と同一の等方性ナノコンポジット磁石粉末を配合混合しない以外は実施例１と同一の製造条件にて異方性ボンド磁石を作成し、得られた異方性ボンド磁石の磁気特性、角型性および空孔率と耐候性試験結果を表３に表す。
【００３８】
比較例２
実施例１にて得られた異方性磁石粉末を用い、またＳｍ１０．５ａｔ％−Ｆｅ８９．５ａｔ％の組成の合金を１１００℃に５０時間の溶体化処理してＮ２ガス雰囲気中でジョークラッシャーおよびパワーミルにて粒径１５０μｍ以下に粉砕後、ＮＨ３＋Ｈ２混合ガス流気中で４００℃、３時間の窒化処理を行った後冷却し、ジェットミルを用いて微粉砕し、粒径３μｍのＳｍ１０ａｔ％−Ｆｅ７７ａｔ％−Ｎ１３ａｔ％組成の磁石粉末を得た。
前記異方性磁石粉末とＳｍ−Ｆｅ−Ｎ系磁石粉末を実施例１との同一の配合比率および同一製造条件に異方性ボンド磁石を作成し、得られた異方性ボンド磁石の磁気特性、角型性および耐候性試験結果および空孔率の結果を表３に表す。
【００３９】
【表１】
【表２】
【表３】
【発明の効果】
この発明による異方性ボンド磁石は、Ｒ−Ｆｅ−Ｂ系合金鋳塊あるいは前記鋳塊を粉砕して得られた粗粉砕粉を、特定の熱処理条件のＨ２処理法により、特定の平均再結晶粒径を有する正方晶のＲ２Ｆｅ１４Ｂ相の再結晶粒集合組織を有する異方性磁石粉末となし、バインダーの樹脂との配合混合前、あるいは配合混合と同時もしくは配合混合後に微細なＲ−Ｆｅ−Ｂ系等方性ナノコンポジット磁石粉末を所定量配合、混合し、成形硬化して、ボンド磁石中の空孔率が減少して磁石内へのＯ２、Ｈ２Ｏの侵入が抑制されるのに加えて、成形時に磁石粉末の割れを抑制でき、ボンド磁石中の非常に活性な金属破面が減少するので実施例に明らかなように、耐熱性、耐候性は一段と向上し、同時にＢｒ、（ＢＨ）ｍａｘ、角型性が向上する。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an anisotropic bonded magnet having excellent heat resistance, weather resistance, and magnetic properties, particularly residual magnetic flux density (hereinafter referred to as Br), and maximum magnetic energy product (hereinafter referred to as (BH) max), and R-Fe- The B-type alloy ingot or the coarsely pulverized powder obtained by pulverizing the ingot is subjected to H 2 treatment under specific heat treatment conditions to form a tetragonal R 2 Fe 14 B phase having a specific average recrystallized grain size. An anisotropic magnet powder having a recrystallized grain texture was obtained, and a specific amount of fine isotropic R-Fe-B nanocomposite magnet powder and a binder resin were mixed and obtained after molding. The present invention relates to an anisotropic bonded magnet having excellent heat resistance, weather resistance, and magnetic properties such as Br and (BH) max.
[0002]
[Prior art]
In general, bonded magnets have rapidly expanded their use range in recent years due to their superior mechanical strength and high degree of freedom in shape, although they are inferior in magnetic properties to sintered magnets. . Such bonded magnets are formed by combining magnet powder with an organic binder, a metal binder, or the like, but the magnetic properties of the bonded magnet depend on the magnetic properties of the magnet powder used.
[0003]
As magnet powder for bond magnets, (1) magnet powder obtained by mechanical pulverization of R—Fe—B ingots or H 2 storage / decay method, or (2) liquid quenching method or atomizing method Thus, magnet powder obtained by ultra-rapid cooling from a molten alloy is used.
[0004]
In the former (1) magnet powder, the R 2 Fe 14 B phase breaks in the grains and is pulverized. Therefore, the R 2 Fe 14 B phase does not become a structure surrounded by the R rich phase, and R 2 Fe 14 B Since the R-rich phase is partly adhered to a part of the phase, and strain remains in the magnet powder during pulverization, the coercive force iHc decreases to 3 kOe or less when pulverized, Even when the magnet powder is an aggregate powder that forms an R-rich phase at the R 2 Fe 14 B phase grain boundary, when used as a bond magnet powder, the iHc of the bond magnet decreases significantly as the molding pressure increases. In addition, there is a drawback that the magnetic properties are lowered when the binder is cured.
[0005]
On the other hand, in the case of the latter (2) magnet powder, since the crystal direction of each R 2 Fe 14 B phase crystal grain is arbitrary and the magnetic properties of the powder are isotropic, the bond magnet itself is also isotropic. For this reason, high magnetic properties cannot be expected, and there is a problem that practical use is limited.
[0006]
Further, in order to obtain a low-cost and high-performance bonded magnet, a high-performance bonded magnet in which a high-performance R-Fe-B magnet powder is added to a ferrite magnet powder has been proposed. The B-based magnet powder is an isotropic magnet powder such as a super-quenched powder or an ingot pulverized powder, and the improvement in magnetic properties was small (Japanese Patent Laid-Open Nos. 61-284906 and 63-287003, and (Kaihei 2-78204, JP-A-3-181104, JP-A-3-222303).
[0007]
[Problems to be solved by the invention]
Therefore, recently, as an anisotropic bond magnet powder, an R—Fe—B alloy ingot or a coarsely pulverized coarsely pulverized powder is obtained from an R 2 Fe 14 B tetragonal phase by an H 2 treatment method under specific heat treatment conditions. An anisotropic R-Fe-B magnet powder having a recrystallized texture is proposed (Japanese Patent Laid-Open No. 1-132106).
[0008]
As a method for producing an anisotropic bonded magnet using the anisotropic magnet powder, a process of adding a resin as a binder to the magnet powder, compression molding, and further performing a heat treatment for curing the binder is generally used. Are known.
[0009]
However, the anisotropic magnetic powder of the raw material powder is very easy to oxidize, and even if the magnetic powder is coated on the powder surface in advance by a coupling process etc., the magnetic powder cracks due to the stress at the time of molding, and the active powder The exposed bonded metal surface is more susceptible to oxidation, and the molded bonded magnet has a low density and has a large number of holes, and O 2 and H 2 O can easily enter the holes to form a bonded magnet. There was a problem that the magnetic properties deteriorated with time due to oxidation.
Further, cracking of the magnet powder during molding means that a large amount of strain is introduced into the magnet powder, which is not preferable from the viewpoint of deteriorating coercive force and squareness.
[0010]
Recently, an anisotropic bonded magnet with an increased packing density by adding Sm-Fe-N magnet powder to anisotropic magnet powder has been proposed (JP-A-6-132107). Although the magnetic properties are improved, there is a problem that the magnetic properties are greatly deteriorated due to the deterioration of the weather resistance of the Sm—Fe—N magnet powder itself.
[0011]
The present invention eliminates the problems of the above-mentioned anisotropic bonded magnet, and does not cause cracking in the magnet powder during molding, and has an excellent anisotropic magnetic property, particularly Br and (BH) max, in addition to weather resistance. The purpose is to provide.
[0012]
[Means for Solving the Problems]
As a result of various investigations to solve the problems of the conventional anisotropic bonded magnet, the inventors considered that the hole portion in the bonded magnet affects the heat resistance and weather resistance, and further examined the results. By adding a specific amount of isotropic R-Fe-B nanocomposite magnet powder and resin to anisotropic R-Fe-B magnet powder,
(1) The isotropic R—Fe—B nanocomposite magnet powder is preferentially filled into the pores of the magnet, the porosity is reduced, and the penetration of O 2 and H 2 O into the magnet is prevented. , Improved heat resistance and weather resistance,
(2) Since the isotropic magnet powder is filled in the holes, the magnetic properties are improved.
(3) Since the powder filling state is improved, the stress concentration applied to the anisotropic magnet powder during molding is reduced, and the cracking of the magnet powder is reduced, thereby reducing the active metal fracture surface, heat resistance and weather resistance. Improved
{Circle around (4)} The present invention has been completed by discovering that such action and effects are synergistic and effective in improving the heat resistance and weather resistance of the bonded magnet and improving the magnetic properties.
[0013]
That is, this invention
Anisotropic R-Fe-B magnet powder having a recrystallized grain texture composed of R 2 Fe 14 B tetragonal phase having an average recrystallized grain size of 0.05 μm to 50 μm, 45 wt% to 98 wt%; An isotropic R-Fe-B nanocomposite magnet powder comprising a soft magnetic phase containing body-centered cubic iron and iron boride having a particle size of 50 nm or less and a hard magnetic phase having Nd 2 Fe 14 B-type crystals 0.9 wt% An anisotropic bonded magnet composed of ˜49 wt% and resin 1 wt% to 10 wt%.
[0014]
Further, the present invention provides the above anisotropic bonded magnet,
R-Fe-B based nanocomposite composition formula of the magnetic powder is R x (Fe 1 - u Co u) 100-x-y-z B y M z, (R: Pr, Nd, 1 kind or two kinds of Dy As described above, x (at%) and y (at (at least one of M, Cr, V, Mo, Al, Si, Cu, Ga, Pb, Au, Pt, and Ag) and the composition are expressed. %), Z (at%) and u are in the following ranges, an anisotropic bonded magnet is also proposed.
3 ≦ x ≦ 6, 10 ≦ y ≦ 30, 0 <z ≦ 10, 0 <u ≦ 0.5
[0015]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, the magnet powder of the recrystallized texture composed of the R 2 Fe 14 B tetragonal phase is homogenized with the R—Fe—B alloy ingot or the coarse particles obtained by coarsely pulverizing the ingot. Or after raising the temperature in the H 2 gas atmosphere without homogenization and maintaining the temperature in the H 2 gas atmosphere for 30 minutes to 8 hours at a temperature of 750 ° C. to 950 ° C. After being kept at 950 ° C. in a vacuum atmosphere for 5 minutes to 4 hours, it is obtained by cooling and pulverizing.
[0016]
The reason why the average particle size of the anisotropic R—Fe—B magnet powder is limited to 5 μm to 500 μm is that if it is less than 5 μm, it tends to oxidize and may burn during operation, and if it exceeds 500 μm, it is practical as a magnet powder. Therefore, the average particle size is preferably 10 μm to 300 μm.
[0017]
Also, if the average recrystallized grain size of anisotropic R-Fe-B magnet powder is less than 0.05 μm, it becomes difficult to magnetize, and if it exceeds 50 μm, iHc (coercive force) becomes 5 kOe or less, and the magnetic properties deteriorate. Therefore, a range of 0.05 μm to 50 μm is set, and a preferable average recrystallized grain size is 0.1 μm to 10 μm.
If the amount of the anisotropic magnet powder is less than 45 wt%, the ratio of the isotropic magnet powder is increased, and the initial magnetic characteristics are reduced. If the amount is more than 98 wt%, the effect of adding the isotropic magnet powder, that is, the filling rate is reduced. The effect of improving the weather resistance and magnetic properties due to the improvement is reduced, and the magnet strength is reduced due to the decrease in the amount of resin, which is not preferable.
[0018]
In this invention, the structure of the isotropic nanocomposite magnet powder blended and mixed with the anisotropic magnet powder is composed of a soft magnetic phase containing body-centered cubic iron and iron boride having an average crystal grain size of 50 nm or less, Nd 2 Fe 14 B It consists of a hard magnetic phase with a type crystal, and the magnetization of the soft magnetic phase is combined with the magnetization of the hard magnetic phase by exchange interaction, so that the composite as a whole consists of a single magnetic phase, like a conventional permanent magnet It is generally called “exchange spring magnet”. The nanocomposite magnetic material is obtained by once obtaining an amorphous metal from a molten state by an ultra-rapid solidification method, crystallizing by heat treatment, and further pulverizing it to obtain a powder.
[0019]
In this invention, the average particle size of the isotropic nanocomposite magnet powder is preferably 1 μm to 50 μm from the viewpoint of preferential entry into the pores of the anisotropic magnet powder.
In addition, if the blending amount of the isotropic nanocomposite magnet powder is less than 0.9 wt%, the porosity reduction effect is small, the heat resistance, weather resistance improvement effect and magnetic property improvement effect cannot be obtained, and 49 wt% If it exceeds 50%, the magnetic properties of the bonded magnet are deteriorated, so 0.9 wt% to 49 wt% is set. A preferable blending amount is 1 wt% to 30 wt%.
[0020]
Further, if the amount of the resin as the binder is less than 1 wt%, the strength of the bonded magnet cannot be sufficiently obtained, and if it exceeds 10 wt%, the magnetic properties are deteriorated, which is not preferable. % To 10 wt%.
The resin may be a known thermosetting or thermoplastic resin, the solid resin may be used as a liquefied binder in a solvent, and the solvent may be volatilized before forming the bonded magnet.
[0021]
The rare earth element R used in the anisotropic R—Fe—B magnet powder of the present invention occupies 10 atomic% to 30 atomic% of the composition, but at least one of Nd, Pr, Dy, Ho, and Tb, or Further, those containing at least one of La, Ce, Sm, Gd, Er, Eu, Tm, Yb, Lu, and Y are preferable. In addition, one type of R is usually sufficient, but in practice, a mixture of two or more types (Misch metal, shidim, etc.) can be used for reasons of convenience. The R may not be a pure rare earth element, and may contain impurities that are inevitable in production within a commercially available range.
[0022]
R is an essential element in the above system magnet powder, and if it is less than 10 atomic%, the crystal structure has a cubic structure having the same structure as α-iron, so that high magnetic properties, particularly high coercive force cannot be obtained, and 30 atoms. If it exceeds 50%, the R-rich non-magnetic phase increases, the residual magnetic flux density (Br) decreases, and a permanent magnet with excellent characteristics cannot be obtained. Therefore, R is preferably in the range of 10 atomic% to 30 atomic%.
[0023]
B is an essential element in the above-mentioned system magnet powder, and if it is less than 2 atomic%, the rhombohedral structure becomes the main phase, and a high coercive force (iHc) cannot be obtained, and if it exceeds 28 atomic%, a B-rich nonmagnetic phase And the residual magnetic flux density (Br) decreases, so that an excellent permanent magnet cannot be obtained. Therefore, B is preferably in the range of 2 atomic% to 28 atomic%.
[0024]
Fe is an essential element in the above system magnet powder, and if it is less than 65 atomic%, the residual magnetic flux density (Br) decreases, and if it exceeds 80 atomic%, a high coercive force cannot be obtained. The content of atomic% is desirable.
Substituting a part of Fe with Co can improve the temperature characteristics without impairing the magnetic characteristics of the obtained magnet. However, if the amount of Co substitution exceeds 20% of Fe, the magnetic characteristics are reversed. Since the characteristics deteriorate, it is not preferable. When the substitution amount of Co is 5 atom% to 15 atom% in terms of the total amount of Fe and Co, (Br) is increased as compared with the case where no substitution is performed, and thus it is preferable for obtaining a high magnetic flux density.
[0025]
In addition to R, B, and Fe, the presence of impurities inevitable in industrial production can be allowed. For example, a part of B is 4.0 wt% or less C, 2.0 wt% or less P, 2.0 wt%. By replacing at least one of the following S and 2.0 wt% or less of Cu with a total amount of 2.0 wt% or less, it is possible to improve the manufacturability of the permanent magnet and reduce the price.
[0026]
Furthermore, at least one of Al, Ti, V, Cr, Mn, Bi, Nb, Ta, Mo, W, Sb, Ge, Ga, Sn, Zr, Ni, Si, Zn, and Hf is based on the magnet powder. It can be added because it is effective in improving the squareness of the coercive force and demagnetization curve, improving the manufacturability, and reducing the price. The upper limit of the amount added is preferably a range that satisfies this condition because (Br) is required to be at least 8 kG or more in order to set (BH) max of the bonded magnet to 14 MGOe or more.
[0027]
In this invention, R of the composition of the isotropic nanocomposite magnet powder to be blended and mixed can provide high magnetic properties only when a specific amount of one or more of Pr, Nd, and Dy is contained. Elements such as Ce and La do not provide iHc with a characteristic of 2 kOe or more, and heavy rare earth elements are not preferred because the magnetic moment tends to be opposite to that of Nd, which tends to significantly reduce magnetization.
If R is less than 3 at%, iHc of 4.0 kOe or more cannot be obtained, and if it exceeds 6 at%, Br of 5 kG or more cannot be obtained. A preferable R amount is 3.5 to 5.5 at%.
[0028]
When B is less than 10 at%, an amorphous structure cannot be obtained even when the ultra-quenching method is used, and only iHc of less than 3 kOe can be obtained by heat treatment, and when it exceeds 30 at%, iHc of 5 kOe or more can be obtained. Therefore, the range is 10 at% to 30 at%. A preferable range is 15 to 20 at%.
[0029]
Co is effective for improving the squareness of the demagnetization curve and temperature characteristics of Co, but if the substitution amount for Fe exceeds 50%, Br of 6 kG or more cannot be obtained, so the Co amount is 0 to 50%. And A preferable range is 0.01 to 0.1%.
[0030]
M improves the iHc by adding one or more of Cr, V, Mo, Al, Si, Cu, Ga, Pb, Au, Pt, and Ag, and the squareness of the demagnetization curve of Br. However, if the amount is less than 0.01 at%, the above-mentioned effect cannot be obtained. If the amount exceeds 10 at%, the squareness deteriorates conversely. Therefore, the addition amount is set to 0.01 at% to 10 at%. A preferred range is from 0.05 at% to 6 at%.
[0031]
【Example】
Example 1
As a raw material, melt casting was performed in a vacuum melting furnace to obtain an alloy ingot for an R—Fe—B magnet having compositions A, B, and C shown in Table 1. These alloy ingots were homogenized in an Ar atmosphere at a temperature of 1120 ° C. for 10 hours.
The ingot is inserted into a heating furnace, and the temperature inside the heating furnace is increased from room temperature to 850 ° C. as 760 Torr of H 2 gas. Subsequently, the temperature is maintained at 850 ° C. for 3 hours, and then maintained at 850 ° C. for 1 hour. Then, H 2 was removed, and the exhaust was cooled until the degree of vacuum became 1 × 10 −5 Torr.
[0032]
Thereafter, the ingot was pulverized in an Ar atmosphere to 300 μm or less to obtain an R—Fe—B magnet powder. The obtained magnet powder was an anisotropic magnet powder having a recrystallized grain texture composed of an R 2 Fe 14 B tetragonal phase having an average crystal grain size of 0.5 μm.
[0033]
Moreover, the R-Fe-B nanocomposite magnet powder to be added and mixed is a copper roll that is rotated at a peripheral speed of 20 m / s using a melt spinning apparatus after melting alloys of compositions a, b, and c shown in Table 2. An amorphous ribbon having a width of 2 to 3 mm was obtained by spraying from a quartz nozzle having a diameter of 0.8 mm.
The ribbon is heated in an Ar gas atmosphere at a heating rate of 15 ° C./min, held at 630 ° C. for about 5 minutes, cooled, pulverized, and body-centered cubic iron and iron boron having an average crystal grain size of 50 μm or less. An isotropic nanocomposite magnet powder having an average particle diameter of 3.8 μm, comprising a soft magnetic phase containing a fluoride and a hard magnetic phase having Nd 2 Fe 14 B type crystals, was obtained.
[0034]
As shown in Table 3, the obtained anisotropic magnet powder having an average particle size of 150 μm, 87 wt%, the isotropic nanocomposite magnet powder having an average particle size of 3.8 μm, and 10 wt% of epoxy resin are blended as shown in Table 3. After mixing, after molding at a molding pressure of 7 ton / cm 2 in a magnetic field of 12 kOe, it was cured by holding at a temperature of 150 ° C. for 1 hour to obtain an anisotropic bonded magnet.
[0035]
Table 3 shows the magnetic properties, squareness, porosity, and weather resistance test results of the obtained anisotropic bonded magnet.
Moreover, the test conditions of the heat resistance and weather resistance test were the conditions of 100 ° C. × 1000 hours in the air, and the change over time of the magnetic flux during the test was measured. The magnetic flux aging test method is to measure the magnetic flux after magnetizing the test piece, and then leave the test piece at 100 ° C. for 1000 hours in the atmosphere, then magnetize the test piece again and measure the magnetic flux. The rate of decrease from the magnetic flux was calculated.
[0036]
Example 2
R-Fe-B anisotropic magnet powder having compositions A, B, and C shown in Table 1 of Example 1, compositions d, e, and f shown in Table 2 manufactured under the same conditions as in Example 1 etc. Using anisotropic nanocomposite magnet powder, 78 wt% anisotropic magnet powder, 20 wt% isotropic nanocomposite magnet powder and 2 wt% epoxy resin are mixed and mixed as shown in Table 3 in a magnetic field of 12 kOe. After forming at 7 ton / cm 2 , the material was cured by holding at 150 ° C. for 1 hour to obtain an anisotropic bonded magnet.
Table 3 shows the magnetic properties, squareness, porosity, and weather resistance test results of the obtained anisotropic bonded magnet.
[0037]
Comparative Example 1
An anisotropic bonded magnet was prepared under the same production conditions as in Example 1 except that the same isotropic nanocomposite magnet powder as in Example 1 was not mixed and mixed with the magnet powder obtained in Example 1. Table 3 shows the magnetic properties, squareness, porosity, and weather resistance test results of the obtained anisotropic bonded magnet.
[0038]
Comparative Example 2
The anisotropic magnet powder obtained in Example 1 was used, and an alloy having a composition of Sm 10.5 at% -Fe 89.5 at% was subjected to a solution treatment at 1100 ° C. for 50 hours, and then a jaw crusher in an N 2 gas atmosphere. And pulverized to a particle size of 150 μm or less with a power mill, then subjected to nitriding treatment at 400 ° C. for 3 hours in an NH 3 + H 2 mixed gas stream, cooled, and finely pulverized using a jet mill. A magnet powder having a composition of Sm 10 at% -Fe 77 at% -N 13 at% was obtained.
An anisotropic bonded magnet was prepared by using the anisotropic magnet powder and the Sm-Fe-N magnet powder in the same blending ratio and the same manufacturing conditions as in Example 1, and the magnetic properties of the obtained anisotropic bonded magnet Table 3 shows the squareness and weather resistance test results and the porosity results.
[0039]
[Table 1]
[Table 2]
[Table 3]
【The invention's effect】
The anisotropic bonded magnet according to the present invention is obtained by subjecting an R—Fe—B alloy ingot or a coarsely pulverized powder obtained by pulverizing the ingot to a specific average re-treatment by H 2 treatment under specific heat treatment conditions. An anisotropic magnet powder having a recrystallized grain texture of a tetragonal R 2 Fe 14 B phase having a crystal grain size is formed, and fine before blending with the binder resin, simultaneously with blending or after blending. A predetermined amount of R-Fe-B isotropic nanocomposite magnet powder is blended, mixed, molded and cured, the porosity in the bonded magnet is reduced, and O 2 and H 2 O penetrate into the magnet. In addition to being suppressed, cracking of the magnet powder during molding can be suppressed, and the extremely active metal fracture surface in the bonded magnet is reduced, so as clearly shown in the examples, heat resistance and weather resistance are further improved. Simultaneously, Br, (BH) max and squareness are improved.
Claims (2)
３≦ｘ≦６、１０≦ｙ≦３０、０＜ｚ≦１０、０＜ｕ≦０．５In claim 1, the composition formula of the R-Fe-B based nanocomposite magnet powder is R x (Fe 1 - u Co u) 100-x-y-z B y M z, (R: Pr, Nd, of Dy X (at%), which is expressed by one or two or more, M: Cr, V, Mo, Al, Si, Cu, Ga, Pb, Au, Pt, or Ag. ), Y (at%), z (at%), and an anisotropic bonded magnet in which u is in the following range.
3 ≦ x ≦ 6, 10 ≦ y ≦ 30, 0 <z ≦ 10, 0 <u ≦ 0.5
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29206095A JP3623564B2 (en) | 1995-10-13 | 1995-10-13 | Anisotropic bonded magnet |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29206095A JP3623564B2 (en) | 1995-10-13 | 1995-10-13 | Anisotropic bonded magnet |
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| Publication Number | Publication Date |
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| JPH09115711A JPH09115711A (en) | 1997-05-02 |
| JP3623564B2 true JP3623564B2 (en) | 2005-02-23 |
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| JP3452254B2 (en) | 2000-09-20 | 2003-09-29 | 愛知製鋼株式会社 | Method for producing anisotropic magnet powder, raw material powder for anisotropic magnet powder, and bonded magnet |
| US7357880B2 (en) | 2003-10-10 | 2008-04-15 | Aichi Steel Corporation | Composite rare-earth anisotropic bonded magnet, composite rare-earth anisotropic bonded magnet compound, and methods for their production |
| JP4608665B2 (en) * | 2004-11-09 | 2011-01-12 | 日立金属株式会社 | Rare earth bonded magnet compound, rare earth bonded magnet, and method for producing them |
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