JP4071911B2 - Rare earth / iron / boron magnets and method for producing the same - Google Patents
Rare earth / iron / boron magnets and method for producing the same Download PDFInfo
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- JP4071911B2 JP4071911B2 JP35740299A JP35740299A JP4071911B2 JP 4071911 B2 JP4071911 B2 JP 4071911B2 JP 35740299 A JP35740299 A JP 35740299A JP 35740299 A JP35740299 A JP 35740299A JP 4071911 B2 JP4071911 B2 JP 4071911B2
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- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 title claims description 147
- 229910052742 iron Inorganic materials 0.000 title claims description 50
- 229910052796 boron Inorganic materials 0.000 title claims description 40
- 229910052761 rare earth metal Inorganic materials 0.000 title claims description 34
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 title claims description 28
- 150000002910 rare earth metals Chemical class 0.000 title claims description 25
- 238000004519 manufacturing process Methods 0.000 title claims description 13
- 239000012071 phase Substances 0.000 claims description 49
- 238000000034 method Methods 0.000 claims description 41
- 239000007791 liquid phase Substances 0.000 claims description 32
- 229910045601 alloy Inorganic materials 0.000 claims description 31
- 239000000956 alloy Substances 0.000 claims description 31
- 229910052779 Neodymium Inorganic materials 0.000 claims description 19
- 238000002844 melting Methods 0.000 claims description 18
- 230000008018 melting Effects 0.000 claims description 18
- 239000002114 nanocomposite Substances 0.000 claims description 18
- 229910000640 Fe alloy Inorganic materials 0.000 claims description 16
- 238000010791 quenching Methods 0.000 claims description 14
- 230000000171 quenching effect Effects 0.000 claims description 14
- 229910052746 lanthanum Inorganic materials 0.000 claims description 11
- 229910000521 B alloy Inorganic materials 0.000 claims description 10
- 229910052802 copper Inorganic materials 0.000 claims description 10
- 229910052782 aluminium Inorganic materials 0.000 claims description 6
- 229910052750 molybdenum Inorganic materials 0.000 claims description 6
- 229910052719 titanium Inorganic materials 0.000 claims description 6
- 229910000881 Cu alloy Inorganic materials 0.000 claims description 5
- 229910052733 gallium Inorganic materials 0.000 claims description 5
- 229910052718 tin Inorganic materials 0.000 claims description 5
- 229910052720 vanadium Inorganic materials 0.000 claims description 5
- 229910052726 zirconium Inorganic materials 0.000 claims description 5
- YPFNIPKMNMDDDB-UHFFFAOYSA-K 2-[2-[bis(carboxylatomethyl)amino]ethyl-(2-hydroxyethyl)amino]acetate;iron(3+) Chemical compound [Fe+3].OCCN(CC([O-])=O)CCN(CC([O-])=O)CC([O-])=O YPFNIPKMNMDDDB-UHFFFAOYSA-K 0.000 claims 1
- 239000000203 mixture Substances 0.000 description 19
- 239000000843 powder Substances 0.000 description 11
- QEFYFXOXNSNQGX-UHFFFAOYSA-N neodymium atom Chemical compound [Nd] QEFYFXOXNSNQGX-UHFFFAOYSA-N 0.000 description 9
- 238000009703 powder rolling Methods 0.000 description 7
- 230000002093 peripheral effect Effects 0.000 description 6
- 239000012535 impurity Substances 0.000 description 5
- 239000007788 liquid Substances 0.000 description 5
- 230000005415 magnetization Effects 0.000 description 5
- 239000002245 particle Substances 0.000 description 5
- 238000004663 powder metallurgy Methods 0.000 description 5
- 229910052777 Praseodymium Inorganic materials 0.000 description 4
- 230000008878 coupling Effects 0.000 description 4
- 238000010168 coupling process Methods 0.000 description 4
- 238000005859 coupling reaction Methods 0.000 description 4
- 239000007789 gas Substances 0.000 description 4
- 238000003825 pressing Methods 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 238000006467 substitution reaction Methods 0.000 description 3
- 238000002441 X-ray diffraction Methods 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- 229910002056 binary alloy Inorganic materials 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000010419 fine particle Substances 0.000 description 2
- 238000005551 mechanical alloying Methods 0.000 description 2
- 238000005245 sintering Methods 0.000 description 2
- -1 B A rare-earth Chemical class 0.000 description 1
- 229910052692 Dysprosium Inorganic materials 0.000 description 1
- 229910002546 FeCo Inorganic materials 0.000 description 1
- 101000993059 Homo sapiens Hereditary hemochromatosis protein Proteins 0.000 description 1
- 229910052771 Terbium Inorganic materials 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000005496 eutectics Effects 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 238000007731 hot pressing Methods 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 229910000765 intermetallic Inorganic materials 0.000 description 1
- 230000005389 magnetism Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 230000001404 mediated effect Effects 0.000 description 1
- 230000006911 nucleation Effects 0.000 description 1
- 238000010899 nucleation Methods 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 229910000938 samarium–cobalt magnet Inorganic materials 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
- 229910000679 solder Inorganic materials 0.000 description 1
- 229910002058 ternary alloy Inorganic materials 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y25/00—Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
-
- 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
-
- 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
- H01F1/0579—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B with exchange spin coupling between hard and soft nanophases, e.g. nanocomposite spring magnets
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Inorganic Chemistry (AREA)
- Crystallography & Structural Chemistry (AREA)
- Power Engineering (AREA)
- Nanotechnology (AREA)
- Composite Materials (AREA)
- Hard Magnetic Materials (AREA)
- Manufacturing Cores, Coils, And Magnets (AREA)
Description
【０００１】
【発明の属する技術分野】
本発明は、電子機器、特にハードディスクドライブのヘッド駆動用アクチュエータに使用すると最適な希土類・鉄・ボロン系磁石及びその製造方法に関する。
【０００２】
【従来の技術】
近年、佐川、Ｃｒｏａｔらにより、Ｎｄ2Ｆｅ14Ｂを主相とするネオジム・鉄・ボロン磁石が発見されて以来、ネオジム・鉄・ボロン系磁石は、その組成や添加物の最適化及び高い磁気特性を引き出す製造方法の開発、改良等により、その磁気特性を改善させてきた。
各種製造方法のうち、粉末冶金法で作られるネオジム・鉄・ボロン系焼結磁石は、化学量論比に近づける低Ｎｄ高Ｆｅ組成化（なお、Ｎｄ2Ｆｅ14Ｂ化合物の原子百分比は、１１．８％Ｎｄ、５．９％Ｂ、８２．３％Ｆｅ）、低酸化プロセス、高磁場配向、組織微細化等の組合せにより、最大エネルギー積（ＢＨ）ｍａｘの理論値の約８８％に相当する（ＢＨ）ｍａｘが実現されている。
しかしながら、粉末冶金法のプロセスや組成の改良等による磁気特性の改善も限界に達しつつある。具体的には、粉末冶金法では、化学量論比組成を超えるＦｅ組成（８２％Ｆｅ以上）をもつ高性能のネオジム・鉄・ボロン系磁石を得ることができない。その理由は、高Ｆｅ組成になると必然的にＦｅ相が生じ、ソフト磁性を有するこのＦｅ相が磁化反転の原因となって保磁力が得られなくなるからであり、また、化学量論比よりＮｄリッチな組成（つまりＦｅプアな組成）で存在する低融点Ｎｄリッチ相が焼結過程で液相となり、Ｎｄ2Ｆｅ14Ｂ粒子の表面をクリーニングすることにより、核発生成長型の保磁力発生に寄与していると考えられているからである。
【０００３】
異方性ネオジム・鉄・ボロン系磁石の製造方法として、粉末冶金法以外には温間一軸変形法が知られている。この方法は、アモルファス薄帯の熱処理あるいは冷却速度の制御により得られたネオジム・鉄・ボロンの微結晶薄帯である急冷薄帯（商品名ＭＱ１、ＭＱＩ社製）をホットプレスでバルク化して、バルク等方性磁石（商品名ＭＱ２、ＭＱＩ社製）とし、該バルク等方性磁石を温間一軸変形することにより、加圧方向に容易磁化軸が配向した異方性ネオジム・鉄・ボロン磁石（商品名ＭＱ３、ＭＱＩ社製）を得る方法である。
温間一軸変形法により得られるネオジム・鉄・ボロン磁石の異方性の程度は、温間加圧変形の程度と相関があり、変形度が大きくなるほど異方性の度合も大きくなる。そして、この方法により、（ＢＨ）ｍａｘの理論値の約７５％に相当する（ＢＨ）ｍａｘが実現されている。
しかしながら、温間一軸変形法は、Ｎｄリッチな低融点相（温間一軸変形過程では液相）が存在する組成でしか変形が起こらないため、低融点相が存在しない化学量論比組成や、より高いＦｅ組成の場合は適用できない。
したがって、従来の温間一軸変形法では、粉末冶金法で得られるネオジム・鉄・ボロン系磁石よりも磁気特性を向上させることは困難であった。
【０００４】
ソフト相とハード相が微細組織（１０ｎｍオーダー）を形成するナノコンポジット磁石は、ソフト相とハード相が交換結合により一体化されている。
そして、このナノコンポジット磁石は、ソフト相が存在しているにもかかわらず永久磁石特性を示すことが、シミュレーションと実測の両方で実証されている。
そのため、上記ソフト相に飽和磁化の高い材料を使用すれば、高い飽和磁化と十分な保磁力を備え、ハード相を超える高い磁気特性を示す可能性がある。
ナノコンポジット磁石では、ソフト相（Ｆｅ、ＦｅＣｏ、Ｆｅ3Ｂ・ＦｅＮ系化合物等）とハード相（Ｎｄ2Ｆｅ14Ｂ、ＳｍＣｏ5 、Ｓｍ2Ｃｏ17、Ｓｍ2Ｆｅ17Ｎｘ、ＮｄＴｉＦｅ11Ｎｘ、その他の窒化物）は、特定の組合せに限定される必然性はなく、括弧内のものを自由に組合せることが可能であり、また、ハード相の組成により常に限定されるわけではない。
【０００５】
しかしながら、ナノコンポジット磁石は、粒子間の交換結合が有効な１０ｎｍオーダーの微細組織においてのみ存在できるものであるが、このような微細組織を異方性化することは実現していない。
ナノコンポジット磁石の特徴は、等方性組織であっても、ソフト相が存在することにより、比較的高いＢｒ（残留磁束密度）を示す点にあるが、等方性組織では十分な保磁力、高い（ＢＨ）ｍａｘを発現することができない。
【０００６】
また、ナノコンポジット磁石には、バルク化できないという問題点もある。ナノコンポジット磁石は、通常、液体急冷法やメカニカルアロイング法等により作製され、粉末又は薄帯の形で得られるが、得られたナノコンポジット組織を肥大化させずに、バルク磁石とする方法はまだ考案されていない。パルス超高圧力により粉体をバルク化させる特殊な方法はあるものの、到底実用化に適した方法ではない。
以上のように、ナノコンポジット磁石において、異方性化とバルク化を同時に実現することは不可能であった。
【０００７】
【発明が解決しようとする課題】
そこで、本発明は、Ｒ2Ｆｅ14Ｂをハード相としたナノコンポジット磁石であって、異方性化かつバルク化した希土類・鉄・ボロン系磁石及びその製造方法を提供することを目的とする。
【０００８】
【課題を解決するための手段】
本発明は、Ｒ（Ｙを含む希土類元素の１種以上）、Ｆｅ（又は所定量のＣｏで置換したＦｅ）、Ｂ、さらには必要によりＭ（Ａｌ、Ｖ、Ｍｏ、Ｚｒ、Ｔｉ、Ｓｎ、Ｃｕ、Ｇａの１種以上、原子百分比で４％以内）よりなり、Ｆｅの比率が８２原子％以上で、ハード相がＲ2Ｆｅ14Ｂ、ソフト相がＦｅ又はＦｅ3Ｂであるナノコンポジット磁石であって、希土類・鉄・ボロン系合金の急冷薄帯から温間一軸変形により、液相の存在下で、直接、異方性化して得られることを特徴とする希土類・鉄・ボロン系磁石である。
別の本発明は、希土類・鉄・ボロン系合金の急冷薄帯を、液相の存在下で、温間一軸変形して、直接、異方性化することを特徴とする上記希土類・鉄・ボロン系磁石の製造方法である。この場合、液相は、ハード相に対して濡れ性のあるＬａ−Ｆｅ系又はＲ−Ｃｕ系の低融点合金からなるのが好ましい。
本発明では、温間一軸変形後に磁石合金周縁部に濃縮される液相を除去し、また、温間一軸変形過程において、保持温度までの昇温は２秒以上５分以内に行い、かつ、保持温度から３００℃以下までの降温は５秒以上１０分以内に行うのがよい。
【０００９】
【発明の実施の形態】
本発明の希土類・鉄・ボロン系磁石は、Ｒ2Ｆｅ14Ｂをハード相とし、該ハード相より飽和磁化の高いソフト相との間で交換結合させ、異方性化かつバルク化したナノコンポジット磁石であり、温間一軸変形過程において、液相が存在する組成で急冷薄帯からの直接温間一軸変形、急速昇温・急速冷却のプロセスにより得られるものである。
【００１０】
本発明の希土類・鉄・ボロン系磁石は、Ｒ（Ｙを含む希土類元素の１種以上）、Ｆｅ（又はＦｅ−Ｃｏ）、Ｂ、さらには必要によりＭ（Ａｌ、Ｖ、Ｍｏ、Ｚｒ、Ｔｉ、Ｓｎ、Ｃｕ、Ｇａの１種以上）よりなり、かつＦｅ（又はＦｅ−Ｃｏ）の比率は、Ｒ2Ｆｅ14Ｂの化学量論比よりＦｅリッチな８２原子％以上の組成をもつナノコンポジット磁石であり、そのハード相はＲ2Ｆｅ14Ｂ（又はＲ2(Ｆｅ−Ｃｏ)14 Ｂ）、ソフト相はＦｅ（又はＦｅ−Ｃｏ）又はＦｅ3 Ｂ（又は (Ｆｅ−Ｃｏ)3Ｂ）からなる。
ＲはＹを含む希土類元素であるが、Ｎｄ、Ｐｒを主体とし、保磁力を増大させるため、Ｒの一部にＴｂやＤｙを使用すると効果的である。
また、上記ＦｅはＣｏで置換可能であるが、Ｃｏ置換によりハード相の磁気特性が低下するので、その置換比率は原子百分比でＦｅとＣｏの合計の２０％を上限とするのが望ましい。
さらに、Ｆｅ又はＦｅ−Ｃｏは添加元素Ｍ（Ａｌ、Ｖ、Ｍｏ、Ｚｒ、Ｔｉ、Ｓｎ、Ｃｕ、Ｇａの１種以上）で少量、置換してもよい。Ｍは組織の微細化に効果があり、保磁力増大に寄与するものの、Ｍによる置換の程度が原子百分比で全組成に対し４％以上になると磁気特性が低下しすぎることになるので、４％以内とするのが望ましい。ただし、Ｍの添加量が少なすぎると微細化の効果が現れなくなるので、好ましくは０．１％以上添加した方がよい。
なお、希土類・鉄・ボロン系合金の作製や磁石製造の工程で混入する、Ｃ、Ｎ、Ｏその他の不純物の量については少ないほど望ましいが、１％以内とすることは不可避である。
【００１１】
本発明の希土類・鉄・ボロン系磁石は、液体急冷法又はメカニカルアロイング法で得られる、薄帯あるいは粉末（以下、これらを急冷薄帯と言う）から製造される。急冷薄帯は粒子間に交換結合が生じた１０ｎｍオーダーの微細組織状態又はアモルファス状態のどちらでもよいが、温間一軸変形の過程で磁石合金微粒子の粒径の肥大を極力抑制するためにはアモルファス状態の方が望ましい。
【００１２】
急冷薄帯を温間一軸変形して直接、異方性化することにより、本発明の希土類・鉄・ボロン系磁石が得られる。従来方法においては、急冷薄帯を温間一軸変形して異方性化する場合、一度ホットプレスにより急冷薄帯をバルク化し、得られた等方性磁石ブロックを、もう一度昇温した後、温間一軸変形して異方性化していた。
しかしながら、本発明では、急冷薄帯を急速昇温して、直接、温間一軸変形する。そのため、異方性化過程では急冷薄帯に対して必要最小限の熱処理しか行われないので、温間一軸変形過程における微細組織の肥大化が抑制され、その結果、粒子間の交換結合が十分に行われることになる。
【００１３】
［従来の技術］で述べたように、Ｆｅの比率が８２原子％以上で、ハード相がＲ2Ｆｅ14Ｂである希土類・鉄・ボロン系合金は、温間で一軸加圧を行っても、ほとんど変形が起こらず異方性化しない。そこで、この問題を解決するため、本発明では、希土類・鉄・ボロン系磁石合金を、Ｆｅの比率が８２原子％以上で、かつ、温間一軸変形の過程で液相が存在するように調製する。この液相は希土類・鉄・ボロン系磁石合金と全く関連性のないもの（例えば、低融点半田合金）では、希土類・鉄・ボロン系磁石合金との濡れ性が悪く、温間一軸変形に寄与しないので、温間一軸変形過程で液相となり、かつ、希土類・鉄・ボロン系磁石合金と濡れ性を有するものが必要となる。本発明者らは、このような条件を満たす合金について種々検討した結果、Ｌａ−Ｆｅ系合金あるいはＲ−Ｃｕ系合金が好ましいことを見出した。このような組織を得るには、組織中にＬａ、Ｃｕを直接添加するか、Ｌａ−Ｆｅ系合金、Ｒ−Ｃｕ系合金をＲ−Ｆｅ−Ｂ系合金に配合させる。この場合、Ｌａ、Ｃｕの添加量は、当初の組成に対し２ｗｔ％以下にすることが好ましい。なお、Ｌａ−Ｆｅ系の二元合金は金属間化合物を作らず、また、Ｌａ−Ｆｅ−Ｂ系の三元合金は、Ｌａ2Ｆｅ14Ｂを非常に生成しにくい。Ｌａ−Ｆｅ系の二元合金は、Ｌａリッチ側で共晶反応により８００℃以下で液相となる。この液相は、元の希土類・鉄・ボロン系磁石合金と類似性がありＲ2 Ｆｅ14Ｂ相との濡れ性が良好であるので、温間一軸変形に寄与する。
一方のＲ−Ｃｕ系合金も、ＣｕはＲ2Ｆｅ14ＢのＦｅを置換せず、かつＲ−Ｃｕ系で生成される化合物は融点が低いため、本発明の液相として適当である。
本発明では、このような低融点相が温間一軸変形過程で液相となり、該液相を介して再配向を行うことにより、従来技術では困難であった異方性化が達成される。
【００１４】
液相を媒介とした温間一軸変形により、急冷薄帯を十分に加圧変形して直接、異方性化した後は、Ｌａ−Ｆｅ系（又はＲ−Ｃｕ系）の低融点合金からなる液相は、圧力がフリーとなる磁石合金周縁部に絞り出されて濃縮される。その際、磁石合金中心部には液相成分はほとんど存在しない状態となる。
従来方法のように、磁石合金を等方性バルク磁石にした後に異方性化する方法では、低融点液相成分は磁石合金周縁部で濃縮されず、内部に均一に分散する。すなわち、低融点液相が磁石合金周縁部で濃縮される現象は、本発明のように、急冷薄帯を直接、温間一軸変形した場合にのみ見られる。低融点液相は非磁性であるため永久磁石の磁気特性には寄与せず、温間一軸変形が終了した後は磁気特性を低下させるのみである。したがって、低融点液相が濃縮された磁石合金周縁部を除去して、ほとんど磁性相よりなる中心部を使用することにより、高い磁気特性を有する異方性ナノコンポジット磁石が得られる。
【００１５】
急冷薄帯の温間一軸変形は、短時間で行わないと微細粒子の肥大化が起こるので、これを避けるために、温間一軸変形過程において、温間一軸変形させる保持温度までの昇温を２秒以上５分以内に行い、かつ、保持温度から３００℃以下までの降温は５秒以上１０分以内に行うことが好ましい。この場合、保持温度は５００〜１０００℃である。
このような短時間の高速昇温と降温が可能な具体的方法の一例として、通電粉末圧延法がある。この方法は、図１に示したように機械粉砕による急冷薄帯の粉末１をホッパー２上部よりロール３内に投入し、被圧延粉末を介して大電流を通電するとロール出口が最高温度となるので、このロール３で粉末１を加圧することによりシート４に成形し、一軸温間変形を行う方法である。この方法によれば加圧する場合、ロール３の軸に平行な方向は圧力が逃げるため一軸圧縮となる。また、ロール３による圧縮が始まるまでは、急冷薄帯は粉末状であるため、通電しても電源５からは電流が流れず、したがって、ほとんど昇温が起こらない。すなわち、ロール３内において、ある程度圧縮されることによって初めて通電し、また、圧延材がロール３を出た時点で通電しなくなって降温フェーズに入るため、急冷薄帯が加熱されている時間は極めて短時間である。
【００１６】
この通電粉末圧延法によれば、アモルファス状態（又は微細結晶状態）から結晶化した組織になるまでに、磁石合金の粒径はあまり肥大せず、１０ｎｍオーダーの微細組織のままの異方性バルク化ナノコンポジット磁石が得られる。
温間一軸変形を行う最高温度と昇温・降温の速度は、ロール３間に通電する電流値とロール３回転数を調節し、加圧変形度合は、ロール間の圧力と間隔を調節することで最適化することができる。通電圧延部は圧延体の酸化劣化を防止するため、不活性ガス雰囲気又は真空雰囲気であることが望ましい。ロール３は１段でも多段でもよい。
なお、温間一軸変形を行う方法は、上記方法に限定されるものではなく、加圧放電焼結法等の同様な機能を有する方法であれば、いずれでもよい。
【００１７】
【実施例】
以下、本発明の実施例を示すが、本発明はこれに限定されるものではない。
（実施例１）
原子百分比で８％Ｎｄ、１％Ｌａ、７６％Ｆｅ、１０％Ｃｏ、５％Ｂ及び不可避の不純物よりなる溶解合金を、減圧Ａｒガス雰囲気下で液体急冷を行い、周速６０ｍ／ｓｅｃの単ロール装置でアモルファス急冷薄帯とした。
次に、該アモルファス急冷薄帯を機械で粉砕して、１００メッシュ以下の粉末とし、Ａｒガス雰囲気内で、通電粉末圧延法により、得られた粉末の異方性化及びバルク薄板化を同時に行った。その際、一軸圧は平均で５００ｋｇ／ｃｍ2 で、電流は１０ｋＡ、ロール周速は１ｍｍ／ｓｅｃであり、温間一軸変形させる保持温度領域（８００℃）まで約２０秒で室温から昇温し、約４０秒で３００℃以下まで降温した。
作製された２０ｍｍ幅で１ｍｍ厚の薄板のうち、Ｌａの大部分が縁部に濃縮されており、該部分である両端２．５ｍｍを除去して、残り１５ｍｍ幅の薄板を加圧方向にＢｒ、ｉＨｃを計測したところ、Ｂｒ＝１．６６Ｔ、ｉＨｃ＝８００ｋＡ／ｍであり、異方性化した磁気特性が得られた。
また、得られた薄板の組成は、８．１％Ｎｄ、０．１％Ｌａ、７６．５％Ｆｅ、１０．１％Ｃｏ、５．１％Ｂであり、Ｆｅ−ＣｏとＮｄ2（Ｆｅ−Ｃｏ）14Ｂよりなっていた。
【００１８】
（参考例１）
原子百分比で６％Ｐｒ、１．５％Ｌａ、８７．５％Ｆｅ、５％Ｂ及び不可避の不純物よりなる溶解合金を、実施例１と同じ条件で急冷してアモルファス急冷薄帯を作製した。また、該条件と同じ条件の通電粉末圧延法でバルク薄板とし、作製された２０ｍｍ幅で１ｍｍ厚の薄板のうち、縁部に濃縮されていたＬａの部分である両端２．５ｍｍを除去して、残り１５ｍｍ幅の薄板を加圧方向（１ｍｍ厚方向）にＢｒ、ｉＨｃを計測したところ、Ｂｒ＝１．５３Ｔ、ｉＨｃ＝９９０ｋＡ／ｍであり、異方性化した磁気特性が得られた。また、得られた薄板の組成は、６．５％Ｐｒ、０．１％Ｌａ、８８％Ｆｅ、５．４％Ｂで、ＦｅとＰｒ2Ｆｅ14Ｂよりなっていた。
【００１９】
（実施例２）
原子百分比で８％Ｎｄ、８２．５％Ｆｅ、８％Ｂ、１％Ａｌ、０．５％Ｔｉ及び不可避の不純物よりなる予め合金化したものを重量比で９５％と、ＳｍＣｕ合金を重量比で５％を所定比に混合し、該混合溶解合金を減圧Ａｒガス雰囲気下で液体急冷を行い、周速６０ｍ／ｓｅｃの単ロール装置でアモルファス急冷薄帯とした。次に、通電粉末圧延の電流値を１５ｋＡとした以外は、実施例１と同様にして縁部に濃縮していたＣｕを除去して薄板を作製し、加圧方向にＢｒ、ｉＨｃを計測したところ、Ｂｒ＝１．４５Ｔ、ｉＨｃ＝１２５０ｋＡ／ｍであり、異方性化した磁気特性が得られた。得られた薄板を手動粉砕した２０メッシュ以下の粉末をＸ線回折で測定したところ、基本的にＮｄ2Ｆｅ14ＢとＦｅ3Ｂからなることが確認できた。
【００２０】
（実施例３）
原子百分比で８％Ｎｄ、１％Ｌａ、８４．５％Ｆｅ、５％Ｂ、１％Ｃｕ、０．５％Ｍｏ及び不可避の不純物よりなる溶解合金を減圧Ａｒガス雰囲気下で液体急冷を行い、周速６０ｍ／ｓｅｃの単ロール装置でアモルファス急冷薄帯とした。次に、通電粉末圧延の電流値を１５ｋＡとした以外は、実施例１と同様にして縁部に濃縮していたＣｕを除去して薄板を作製し、加圧方向にＢｒ、ｉＨｃを計測したところ、Ｂｒ＝１．５３Ｔ、ｉＨｃ＝１０４０ｋＡ／ｍであり、異方性化した磁気特性が得られた。得られた薄板を手動粉砕した２０メッシュ以下の粉末をＸ線回折で測定したところ、基本的にＮｄ2Ｆｅ14ＢとＦｅ3Ｂからなることが確認できた。
【００２１】
【発明の効果】
本発明により、希土類・鉄・ボロン系磁石合金を、液相の存在下、高速昇温、高速降温条件で直接、温間一軸変形することにより、今までナノコンポジット磁石で不可能であった異方性化とバルク化を同時に実現することができる。これにより、Ｒ2Ｆｅ14Ｂ組成より高Ｆｅ側で、Ｒ2Ｆｅ14Ｂ相のバルク磁気特性を超える値を得ることが可能となった。
【図面の簡単な説明】
【図１】通電粉末圧延法の概念図である。
【符号の説明】
１ 粉末 ４ シート
２ ホッパー ５ 電源
３ ロール[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rare earth / iron / boron magnet that is optimal for use in an electronic device, particularly a head drive actuator of a hard disk drive, and a method of manufacturing the same.
[0002]
[Prior art]
Since the discovery of neodymium / iron / boron magnets with Nd 2 Fe 14 B as the main phase by Sagawa, Croat et al. In recent years, neodymium / iron / boron magnets have been optimized for their composition and additives and high magnetic properties. The magnetic properties have been improved by developing, improving, etc., manufacturing methods that bring out the properties.
Among various manufacturing methods, neodymium / iron / boron sintered magnets made by powder metallurgy are low in Nd and high in Fe composition close to the stoichiometric ratio (Note that the atomic percentage of Nd 2 Fe 14 B compound is 11 .8% Nd, 5.9% B, 82.3% Fe), equivalent to about 88% of the theoretical value of maximum energy product (BH) max due to a combination of low oxidation process, high magnetic field orientation, microstructure refinement, etc. (BH) max is realized.
However, the improvement of magnetic properties by improving the process and composition of powder metallurgy is reaching its limit. Specifically, high-performance neodymium / iron / boron magnets having an Fe composition exceeding the stoichiometric composition (82% Fe or more) cannot be obtained by powder metallurgy. The reason is that an Fe phase is inevitably generated at a high Fe composition, and this Fe phase having soft magnetism causes a magnetization reversal so that a coercive force cannot be obtained. The low melting point Nd rich phase present in a rich composition (ie Fe poor composition) becomes a liquid phase during the sintering process, and the surface of the Nd 2 Fe 14 B particles is cleaned to generate a nucleation growth type coercive force. It is because it is thought that it contributes.
[0003]
As a method for producing an anisotropic neodymium / iron / boron magnet, a warm uniaxial deformation method is known in addition to the powder metallurgy method. In this method, a quenching ribbon (trade name MQ1, manufactured by MQI), which is a microcrystalline ribbon of neodymium / iron / boron obtained by heat treatment or cooling rate control of the amorphous ribbon, is bulked with a hot press, Anisotropic neodymium / iron / boron magnet with easy magnetization axis oriented in the pressurizing direction by deforming the bulk isotropic magnet (product name MQ2, manufactured by MQI) and warm uniaxial deformation of the bulk isotropic magnet (Trade name MQ3, manufactured by MQI).
The degree of anisotropy of the neodymium / iron / boron magnet obtained by the warm uniaxial deformation method correlates with the degree of warm pressure deformation, and the degree of anisotropy increases as the degree of deformation increases. By this method, (BH) max corresponding to about 75% of the theoretical value of (BH) max is realized.
However, in the warm uniaxial deformation method, deformation occurs only in a composition in which a low melting point phase rich in Nd (a liquid phase in the warm uniaxial deformation process) exists, so a stoichiometric composition in which no low melting point phase exists, Not applicable for higher Fe compositions.
Therefore, in the conventional warm uniaxial deformation method, it has been difficult to improve the magnetic properties as compared with neodymium / iron / boron magnets obtained by powder metallurgy.
[0004]
In the nanocomposite magnet in which the soft phase and the hard phase form a fine structure (on the order of 10 nm), the soft phase and the hard phase are integrated by exchange coupling.
And it has been proved by both simulation and measurement that this nanocomposite magnet exhibits permanent magnet characteristics despite the presence of the soft phase.
Therefore, if a material having a high saturation magnetization is used for the soft phase, there is a possibility that a high saturation magnetization and a sufficient coercive force are provided, and a high magnetic property exceeding the hard phase is exhibited.
In nanocomposite magnets, soft phases (Fe, FeCo, Fe 3 B / FeN compounds, etc.) and hard phases (Nd 2 Fe 14 B, SmCo 5 , Sm 2 Co 17 , Sm 2 Fe 17 Nx, NdTiFe 11 Nx, etc. Are not necessarily limited to a specific combination, and those in parentheses can be freely combined, and are not always limited by the composition of the hard phase.
[0005]
However, a nanocomposite magnet can exist only in a microstructure of the order of 10 nm where exchange coupling between particles is effective, but anisotropy of such a microstructure has not been realized.
The nanocomposite magnet is characterized by a relatively high Br (residual magnetic flux density) due to the presence of a soft phase even in an isotropic structure. High (BH) max cannot be expressed.
[0006]
In addition, nanocomposite magnets have a problem that they cannot be bulked. Nanocomposite magnets are usually produced by liquid quenching method, mechanical alloying method, etc., and obtained in the form of powder or ribbon, but the method to make bulk magnet without enlargement of the obtained nanocomposite structure is It has not yet been devised. Although there is a special method for bulking powder by pulse ultra-high pressure, it is not a method suitable for practical use.
As described above, it has been impossible to simultaneously achieve anisotropy and bulking in a nanocomposite magnet.
[0007]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to provide a nanocomposite magnet having R 2 Fe 14 B as a hard phase, an anisotropic and bulked rare earth / iron / boron magnet, and a method for manufacturing the same. .
[0008]
[Means for Solving the Problems]
The present invention includes R (one or more rare earth elements including Y), Fe (or Fe substituted with a predetermined amount of Co), B, and optionally M (Al, V, Mo, Zr, Ti, Sn, A nanocomposite magnet composed of one or more of Cu and Ga, within an atomic percentage of 4% or less), an Fe ratio of 82 atomic% or more, a hard phase of R 2 Fe 14 B, and a soft phase of Fe or Fe 3 B A rare-earth / iron / boron-based magnet obtained by rapid anisotropy in the presence of a liquid phase from a rapidly cooled ribbon of a rare-earth / iron / boron alloy in the presence of a liquid phase. It is.
Another aspect of the present invention is the above-described rare earth / iron / boron alloy, characterized in that a rapidly quenched ribbon of a rare earth / iron / boron alloy is subjected to warm uniaxial deformation in the presence of a liquid phase and directly anisotropy. This is a method for manufacturing a boron-based magnet. In this case, the liquid phase is preferably made of a La—Fe-based or R—Cu-based low melting point alloy having wettability with respect to the hard phase.
In the present invention, the liquid phase concentrated on the periphery of the magnet alloy after the warm uniaxial deformation is removed, and in the process of the warm uniaxial deformation, the temperature rise to the holding temperature is performed within 2 seconds to 5 minutes, and The temperature drop from the holding temperature to 300 ° C. or lower is preferably performed within 5 seconds to 10 minutes.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
The rare earth / iron / boron magnet of the present invention is a nanocomposite in which R 2 Fe 14 B is used as a hard phase and exchange coupled with a soft phase having a saturation magnetization higher than that of the hard phase to make it anisotropic and bulk. It is a magnet and is obtained by a process of direct warm uniaxial deformation, rapid heating and rapid cooling from a rapidly cooled ribbon with a composition in which a liquid phase exists in the process of warm uniaxial deformation.
[0010]
The rare earth / iron / boron magnet of the present invention includes R (one or more rare earth elements including Y), Fe (or Fe—Co), B, and optionally M (Al, V, Mo, Zr, Ti). , Sn, Cu, and Ga), and the ratio of Fe (or Fe—Co) is more than 82 atomic% of a composition rich in Fe than the stoichiometric ratio of R 2 Fe 14 B. It is a magnet, and its hard phase is R 2 Fe 14 B (or R 2 (Fe—Co) 14 B), and the soft phase is Fe (or Fe—Co) or Fe 3 B (or (Fe—Co) 3 B). Consists of.
R is a rare earth element containing Y, but it is effective to use Tb or Dy as a part of R in order to increase coercive force mainly with Nd and Pr.
Further, although the above Fe can be substituted by Co, the magnetic property of the hard phase is lowered by Co substitution. Therefore, the substitution ratio is desirably 20% of the total of Fe and Co in terms of atomic percentage.
Further, Fe or Fe—Co may be replaced with a small amount by the additive element M (one or more of Al, V, Mo, Zr, Ti, Sn, Cu, and Ga). Although M is effective in making the structure finer and contributes to an increase in coercive force, if the degree of substitution by M is 4% or more of the total composition in terms of atomic percentage, the magnetic properties will be deteriorated too much, so 4% It is desirable to be within. However, if the amount of M added is too small, the effect of miniaturization will not appear, so it is preferable to add 0.1% or more.
The amount of C, N, O and other impurities mixed in the rare earth / iron / boron alloy production and magnet manufacturing steps is preferably as small as possible, but it is inevitable to be within 1%.
[0011]
The rare earth / iron / boron magnet of the present invention is manufactured from a ribbon or powder (hereinafter referred to as a quenching ribbon) obtained by a liquid quenching method or a mechanical alloying method. The quenched ribbon may be in the microstructure or amorphous state of the order of 10 nm where exchange coupling occurs between the particles, but in order to suppress the enlargement of the particle diameter of the magnet alloy fine particles as much as possible during the process of warm uniaxial deformation, it is amorphous. The state is preferred.
[0012]
The rare-earth / iron / boron magnet of the present invention can be obtained by directly deforming the quenched ribbon by uniaxial warm deformation. In the conventional method, when the quenched ribbon is warm uniaxially deformed and made anisotropic, the quenched ribbon is once bulked by hot pressing, and the obtained isotropic magnet block is heated once again, It was uniaxially deformed and made anisotropic.
However, in the present invention, the rapidly cooled ribbon is rapidly heated and directly deformed in a uniaxial manner. For this reason, only the minimum necessary heat treatment is applied to the quenched ribbon in the anisotropy process, so that the microstructure enlargement in the warm uniaxial deformation process is suppressed, and as a result, the exchange coupling between the particles is sufficient. Will be done.
[0013]
As described in [Prior Art], a rare earth / iron / boron alloy having a Fe ratio of 82 atomic% or more and a hard phase of R 2 Fe 14 B can be warmly uniaxially pressed. Almost no deformation occurs and no anisotropy occurs. Therefore, in order to solve this problem, in the present invention, a rare earth / iron / boron magnet alloy is prepared so that the Fe ratio is 82 atomic% or more and a liquid phase exists in the process of warm uniaxial deformation. To do. If this liquid phase has nothing to do with rare earth / iron / boron magnet alloys (for example, low melting point solder alloys), the wettability with rare earth / iron / boron magnet alloys is poor, contributing to warm uniaxial deformation. Therefore, it is necessary to have a liquid phase in the process of warm uniaxial deformation and have wettability with rare earth / iron / boron magnet alloys. As a result of various studies on alloys that satisfy such conditions, the present inventors have found that La—Fe based alloys or R—Cu based alloys are preferable. In order to obtain such a structure, La and Cu are directly added to the structure, or a La—Fe alloy and an R—Cu alloy are mixed with the R—Fe—B alloy. In this case, the addition amount of La and Cu is preferably 2 wt% or less with respect to the initial composition. Note that a La—Fe-based binary alloy does not form an intermetallic compound, and a La—Fe—B-based ternary alloy hardly generates La 2 Fe 14 B. The La—Fe-based binary alloy becomes a liquid phase at 800 ° C. or lower due to a eutectic reaction on the La rich side. This liquid phase is similar to the original rare earth / iron / boron magnet alloy and has good wettability with the R 2 Fe 14 B phase, thus contributing to warm uniaxial deformation.
One R-Cu alloy is also suitable as the liquid phase of the present invention because Cu does not replace Fe in R 2 Fe 14 B, and the compound produced in the R-Cu system has a low melting point.
In the present invention, such a low melting point phase becomes a liquid phase in the process of warm uniaxial deformation, and reorientation is performed through the liquid phase, thereby achieving anisotropy that was difficult in the prior art.
[0014]
It is made of La-Fe-based (or R-Cu-based) low-melting-point alloy after it is deformed by direct pressure anisotropy by sufficient pressure deformation of the quenched ribbon by warm uniaxial deformation mediated by liquid phase. The liquid phase is squeezed out and concentrated on the periphery of the magnet alloy where the pressure is free. At that time, there is almost no liquid phase component in the center of the magnet alloy.
In the conventional method, in which the magnet alloy is made an isotropic bulk magnet and then made anisotropic, the low melting point liquid phase component is not concentrated at the periphery of the magnet alloy but is uniformly dispersed therein. That is, the phenomenon that the low melting point liquid phase is concentrated at the peripheral edge of the magnet alloy can be seen only when the rapidly cooled ribbon is directly deformed in a warm uniaxial manner as in the present invention. Since the low-melting-point liquid phase is non-magnetic, it does not contribute to the magnetic properties of the permanent magnet, and only reduces the magnetic properties after the warm uniaxial deformation is completed. Therefore, an anisotropic nanocomposite magnet having high magnetic properties can be obtained by removing the peripheral edge of the magnet alloy in which the low melting point liquid phase is concentrated and using the central portion consisting almost of the magnetic phase.
[0015]
To avoid this, warm uniaxial deformation of the quenching ribbon will cause enlargement of fine particles unless it is performed in a short time. It is preferable to carry out within 2 seconds to 5 minutes, and to lower the temperature from the holding temperature to 300 ° C. or less within 5 seconds to 10 minutes. In this case, the holding temperature is 500 to 1000 ° C.
As an example of a specific method capable of such high-speed temperature rise and temperature drop for a short time, there is an energization powder rolling method. In this method, as shown in FIG. 1, a rapidly cooled ribbon 1 by mechanical pulverization is put into the roll 3 from the upper part of the hopper 2 and a large current is passed through the powder to be rolled, so that the roll outlet reaches the maximum temperature. Therefore, it is a method of forming the sheet 4 by pressurizing the powder 1 with this roll 3 and performing uniaxial warm deformation. According to this method, when pressure is applied, the direction parallel to the axis of the roll 3 is uniaxially compressed because the pressure escapes. Further, until the compression by the roll 3 is started, since the rapidly cooled ribbon is in a powder form, no current flows from the power source 5 even when energized. That is, the roll 3 is energized for the first time by being compressed to some extent, and when the rolled material leaves the roll 3, it is not energized and enters the temperature lowering phase. It is a short time.
[0016]
According to this energization powder rolling method, the grain size of the magnet alloy does not increase so much from the amorphous state (or fine crystal state) to the crystallized structure, and the anisotropic bulk remains in the fine structure of the order of 10 nm. Nanocomposite magnet is obtained.
The maximum temperature for warm uniaxial deformation and the rate of temperature increase / decrease adjust the value of the current flowing between the rolls 3 and the number of rotations of the roll 3, and the degree of pressure deformation is the pressure and interval between the rolls. Can be optimized. In order to prevent oxidative deterioration of the rolled product, the energized rolling part is desirably an inert gas atmosphere or a vacuum atmosphere. The roll 3 may be one stage or multiple stages.
Note that the method for performing the warm uniaxial deformation is not limited to the above method, and any method may be used as long as it has a similar function such as a pressure discharge sintering method.
[0017]
【Example】
Examples of the present invention will be described below, but the present invention is not limited thereto.
Example 1
A molten alloy composed of 8% Nd, 1% La, 76% Fe, 10% Co, 5% B and unavoidable impurities in terms of atomic percentage is subjected to liquid quenching in a reduced pressure Ar gas atmosphere, and a peripheral speed of 60 m / sec. A roll apparatus was used to form an amorphous quenching ribbon.
Next, the amorphous quenching ribbon is pulverized by a machine to a powder of 100 mesh or less, and the obtained powder is anisotropicized and bulk-thinned simultaneously by an energization powder rolling method in an Ar gas atmosphere. It was. At that time, the average uniaxial pressure is 500 kg / cm 2 , the current is 10 kA, the roll peripheral speed is 1 mm / sec, and the temperature is raised from room temperature in about 20 seconds to the holding temperature region (800 ° C.) for the uniaxial deformation in warm. The temperature was lowered to 300 ° C. or less in about 40 seconds.
Of the produced 20 mm wide and 1 mm thick thin plate, most of La is concentrated at the edge, 2.5 mm of both ends being removed, and the remaining 15 mm wide thin plate in the pressing direction is Br. , IHc was measured, Br = 1.66T, iHc = 800 kA / m, and anisotropic magnetic characteristics were obtained.
Moreover, the composition of the obtained thin plate is 8.1% Nd, 0.1% La, 76.5% Fe, 10.1% Co, 5.1% B, and Fe—Co and Nd 2 (Fe -Co) 14 B.
[0018]
( Reference Example 1)
A molten alloy comprising 6% Pr, 1.5% La, 87.5% Fe, 5% B and unavoidable impurities in terms of atomic percentage was quenched under the same conditions as in Example 1 to prepare an amorphous quenched ribbon. In addition, a bulk thin plate was formed by a current-powder rolling method under the same conditions as above, and 2.5 mm at both ends, which was a portion of La concentrated on the edge, was removed from the produced thin plate having a width of 20 mm and a thickness of 1 mm. When the remaining thin plate with a width of 15 mm was measured for Br and iHc in the pressing direction (1 mm thickness direction), Br = 1.53T and iHc = 990 kA / m, and anisotropic magnetic characteristics were obtained. The composition of the obtained thin plate was 6.5% Pr, 0.1% La, 88% Fe, 5.4% B, and consisted of Fe and Pr 2 Fe 14 B.
[0019]
(Example 2 )
A pre-alloyed material consisting of 8% Nd, 82.5% Fe, 8% B, 1% Al, 0.5% Ti and inevitable impurities in terms of atomic percentage is 95% by weight, and SmCu alloy is in weight ratio. 5% was mixed in a predetermined ratio, and the mixed molten alloy was subjected to liquid quenching in a reduced pressure Ar gas atmosphere, and an amorphous quenching ribbon was formed using a single roll apparatus having a peripheral speed of 60 m / sec. Next, except that the current value of the energization powder rolling was set to 15 kA, a thin plate was prepared by removing Cu concentrated at the edge in the same manner as in Example 1, and Br and iHc were measured in the pressing direction. However, Br = 1.45T and iHc = 1250 kA / m, and anisotropic magnetic characteristics were obtained. When the obtained thin plate was manually pulverized and the powder of 20 mesh or less was measured by X-ray diffraction, it was confirmed that it was basically composed of Nd 2 Fe 14 B and Fe 3 B.
[0020]
(Example 3 )
Liquid quenching is performed in a reduced pressure Ar gas atmosphere with a molten alloy composed of 8% Nd, 1% La, 84.5% Fe, 5% B, 1% Cu, 0.5% Mo and inevitable impurities in atomic percentages. A single roll apparatus with a peripheral speed of 60 m / sec was used to form an amorphous quenching ribbon. Next, except that the current value of the energization powder rolling was set to 15 kA, a thin plate was prepared by removing Cu concentrated at the edge in the same manner as in Example 1, and Br and iHc were measured in the pressing direction. However, Br = 1.53T and iHc = 1040 kA / m, and anisotropic magnetic characteristics were obtained. When the obtained thin plate was manually pulverized and the powder of 20 mesh or less was measured by X-ray diffraction, it was confirmed that it was basically composed of Nd 2 Fe 14 B and Fe 3 B.
[0021]
【The invention's effect】
According to the present invention, a rare earth / iron / boron-based magnet alloy is deformed directly in the presence of a liquid phase under high-speed temperature rise and temperature-decrease conditions. It is possible to achieve both directivity and bulk. This makes it possible to obtain a value that exceeds the bulk magnetic properties of the R 2 Fe 14 B phase on the higher Fe side than the R 2 Fe 14 B composition.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram of an energization powder rolling method.
[Explanation of symbols]
1 Powder 4 Sheet 2 Hopper 5 Power supply 3 Roll
Claims (4)
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| JP35740299A JP4071911B2 (en) | 1998-12-17 | 1999-12-16 | Rare earth / iron / boron magnets and method for producing the same |
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| JP35740299A JP4071911B2 (en) | 1998-12-17 | 1999-12-16 | Rare earth / iron / boron magnets and method for producing the same |
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| WO2001091139A1 (en) | 2000-05-24 | 2001-11-29 | Sumitomo Special Metals Co., Ltd. | Permanent magnet including multiple ferromagnetic phases and method for producing the magnet |
| US7217328B2 (en) | 2000-11-13 | 2007-05-15 | Neomax Co., Ltd. | Compound for rare-earth bonded magnet and bonded magnet using the compound |
| HU227736B1 (en) | 2001-05-15 | 2012-02-28 | Hitachi Metals Ltd | Iron-based rare earth alloy nanocomposite magnet and method for producing the same |
| JP3983999B2 (en) | 2001-05-17 | 2007-09-26 | 日産自動車株式会社 | Manufacturing method of anisotropic exchange spring magnet and motor comprising the same |
| US7507302B2 (en) | 2001-07-31 | 2009-03-24 | Hitachi Metals, Ltd. | Method for producing nanocomposite magnet using atomizing method |
| US7261781B2 (en) | 2001-11-22 | 2007-08-28 | Neomax Co., Ltd. | Nanocomposite magnet |
| US7371292B2 (en) | 2002-11-12 | 2008-05-13 | Nissan Motor Co., Ltd. | Nd-Fe-B type anisotropic exchange spring magnet and method of producing the same |
| US6979409B2 (en) * | 2003-02-06 | 2005-12-27 | Magnequench, Inc. | Highly quenchable Fe-based rare earth materials for ferrite replacement |
| JP2007123467A (en) * | 2005-10-27 | 2007-05-17 | Honda Motor Co Ltd | Method for manufacturing anisotropic magnet |
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