JP4371188B2 - High specific electric resistance rare earth magnet and method for manufacturing the same - Google Patents
High specific electric resistance rare earth magnet and method for manufacturing the same Download PDFInfo
- Publication number
- JP4371188B2 JP4371188B2 JP2000250597A JP2000250597A JP4371188B2 JP 4371188 B2 JP4371188 B2 JP 4371188B2 JP 2000250597 A JP2000250597 A JP 2000250597A JP 2000250597 A JP2000250597 A JP 2000250597A JP 4371188 B2 JP4371188 B2 JP 4371188B2
- Authority
- JP
- Japan
- Prior art keywords
- rare earth
- alloy
- high specific
- powder
- earth magnet
- 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.)
- Expired - Fee Related
Links
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
- H01F1/0577—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 sintered
Landscapes
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Manufacturing Cores, Coils, And Magnets (AREA)
- Powder Metallurgy (AREA)
- Manufacture Of Alloys Or Alloy Compounds (AREA)
- Hard Magnetic Materials (AREA)
Description
【０００１】
【発明の属する技術分野】
本発明は、特に、回転機器、電子部品、電気機器の産業分野で有用な、高比電気抵抗性希土類磁石及びその製造方法に関するものである。
【０００２】
【従来の技術】
Ｒ（ＲはＹを含む希土類元素の１種以上、以下同じ），Ｆｅ，Ｃｏ，Ｂからなる永久磁石、特にＲとしてＮｄを主成分とする希土類磁石は、その磁気特性の高さから電子・電気機器産業の分野において、広く利用されている。
【０００３】
例えば、永久磁石式回転機器には、従来安価なフェライト磁石が主に使用されてきた。しかし近年、回転機器の更なる小型化、効率化の要求に対して、高価ではあるが磁気特性の高い希土類磁石が使用されるようになった。一般に市販されている希土類磁石のうち、Ｓｍ−Ｃｏ系磁石はキュリー温度が高いため、磁気特性の温度変化が小さい。また耐食性も高く、表面処理を必要としない。しかし、原料としてＣｏを使用しているため、非常に高価である。一方、Ｎｄ−Ｆｅ−Ｂ系磁石は永久磁石の中で飽和磁化が最も高く、また原料でＣｏを使用しないので安価である。しかし、キュリー温度が低いため、磁気特性の温度変化が大きく、耐熱性に劣る。同時に耐食性も劣っているため、用途によっては適当な表面処理を必要とする。
【０００４】
【発明が解決しようとする課題】
希土類磁石は金属であるので、比電気抵抗は酸化物であるフェライトの比電気抵抗の１００分の１程度の１００〜２００μΩｃｍ程度と小さい。従って、モータなど回転機器でこの希土類磁石が変動する磁界にさらされながら使用される場合、電磁誘導により発生した渦電流が大量に流れ、その電流によるジュール熱により永久磁石が発熱する。永久磁石の温度が高くなると、特にＮｄ−Ｆｅ−Ｂ系磁石は磁気特性の温度変化が大きいため、磁気特性が低下し、その結果モータの効率も落ちる。
【０００５】
この対策の一つとして、磁石の保磁力を大きくすることが挙げられる。磁石の保磁力を大きくすることにより、磁石の耐熱性が増し、不可逆減磁を起こしにくくなる。特にＮｄ−Ｆｅ−Ｂ系磁石はそのキュリー温度の低さから磁気特性の温度変化が大きく、その保磁力を高める様々な試みがなされてきた。
【０００６】
その保磁力を高めるのに最も効果が現れた方法は、その主相となるＲ2（Ｆｅ，Ｃｏ）14Ｂ相のＲの一部をＤｙやＴｂといった重希土類に置換し、結晶磁気異方性を高めるやり方であった。しかしこの方法では磁石の飽和磁化は小さくなり、また重希土類は非常に高価であるため磁石のコストがあがる。
【０００７】
渦電流を抑えるための方法に、永久磁石を小分割して絶縁する方法がある。この方法は、磁石の分割数に反比例して発熱量を小さくする効果があるが、磁石加工のコストを上げてしまう。
【０００８】
そこで、渦電流に対する抜本的な対策として、希土類磁石そのものの比電気抵抗を大きくしようとする試みがなされている。
【０００９】
樹脂バインダを使用したＮｄ−Ｆｅ−Ｂ系希土類ボンド磁石の比電気抵抗は、Ｎｄ−Ｆｅ−Ｂ系焼結磁石と比較して１００倍程度高いが、冷凍機などコンプレッサ用モータに使用した場合、冷媒として用いる代替フロンと樹脂バインダが反応してしまい、耐溶媒性に問題がある。また、特開平５−１２１２２０号公報には、ボンド磁石粉をゾル・ゲル法等によりセラミックスバインダでコートし、その後に成形金型中で直接圧縮通電して、フル密度磁石を得る方法が提案されている。この方法は、磁石を硬化する際にセラミックスバインダのガラス転移温度（約５００℃）以上の加熱を必要とするためにバインダとの反応等による磁粉の劣化が進行し、実用に供し得るに十分な磁気特性と高い比電気抵抗を両立させることは困難である。特開平１０−３２１４２７号公報には、ボンド磁石粉を液状無機バインダを用いてより低温で結着する方法が提案されているが、実用十分な磁気特性と高比電気抵抗を具備することが困難である。特開平９−１８６０１０号及び特開平１０−１６３０５５号公報には、希土類磁石粉末を絶縁物で希土類磁石と反応しないアルカリ金属又はアルカリ土類金属のフッ化物及び／又は酸化物と混合したのち密度化して、高比電気抵抗磁石を得る方法が提案されている。この方法では高い比電気抵抗を得るためには相当量の絶縁物を添加せねばならず、希土類磁石相の体積が大きく減少し、磁化が低下するため、実用十分な磁気特性と高い比電気抵抗の両立が難しい。特開平１１−３２９８０９号公報では、磁化方向に電気抵抗率の高い層を積層し、表皮効果により渦電流の流れる部分の比電気抵抗だけを上げてジュール熱による発熱を抑えようという方法が提案されている。これは外部磁界の変動方向と磁石の磁化方向が平行な場合は有効だが、実際のモータのようにその方向が絶えずずれるような場合有効ではない。
【００１０】
従って、本発明は高い比電気抵抗と十分な磁気特性を共に備えた高比電気抵抗性希土類磁石及びその製造方法を提供することを目的とする。
【００１１】
【課題を解決するための手段及び発明の実施の形態】
本発明者らは、高い比電気抵抗と十分な磁気特性を併せ持つような希土類元素・鉄・ボロン系焼結磁石を得るために様々な方法を考察、検討した。その結果、Ｒ−Ｔ−Ｂ合金［ＲはＹを含む希土類元素の１種以上（以下同じ）、ＴはＦｅ及び／又はＣｏ（以下同じ）］及び／又はＲ−Ｔ−Ｍ−Ｂ合金［ＭはＡｌ，Ｓｉ，Ｔｉ，Ｖ，Ｃｒ，Ｃｕ，Ｚｒ，Ｎｂ，Ｍｏ，Ｔａ，Ｗ，Ｇａ，Ｓｎのいずれかより選ばれた１又は２以上の元素（以下同じ）］のインゴット合金又は急冷薄帯を粉砕する工程において、Ｂ2Ｏ3粉末を混合、粉砕し、磁場中配向成形後、焼結することにより、１種以上の希土類酸化物Ｒ’ｍＯｎ［Ｒ’はＹを含む希土類元素の１種以上で、ｍ，ｎは、それぞれＣｅの場合１，２又は２，３、Ｐｒの場合２，３又は６，１１、Ｔｂの場合２，３又は４，７、その他は全て２，３である（以下同じ）］及び／又は希土類元素Ｒ’’［Ｒ’’はＹを含む希土類元素の１種以上（以下同じ）］とＢとの複合酸化物を含み、残部がＲ−Ｔ−Ｂ合金及び／又はＲ−Ｔ−Ｍ−Ｂ合金である高比電気抵抗性希土類磁石が得られることを見出し、更に諸条件を確認して本発明を完成した。
【００１２】
即ち、本発明は、
（１）１種以上の希土類酸化物Ｒ’ｍＯｎ及び希土類元素Ｒ’’とＢとの複合酸化物を含み、残部がＲ−Ｔ−Ｂ合金及び／又はＲ−Ｔ−Ｍ−Ｂ合金であることを特徴とする高比電気抵抗性希土類磁石、及び、
（２）Ｒ−Ｔ−Ｂ合金及び／又はＲ−Ｔ−Ｍ−Ｂ合金のインゴット合金又は急冷薄帯を粉砕する工程において、Ｂ2Ｏ3粉末を混合、粉砕し、磁場中配向成形後、１０００〜１２００℃の温度で焼結することを特徴とする高比電気抵抗性希土類磁石の製造方法
を提供する。
【００１３】
以下、本発明を詳細に説明する。
本発明によれば、
▲１▼Ｒ−Ｔ−Ｂ合金及び／又はＲ−Ｔ−Ｍ−Ｂ合金のインゴット合金又は急冷薄帯を粉砕する工程において、Ｂ2Ｏ3粉末を混合、粉砕し、磁場中配向成形後、焼結する
▲２▼必要により、得られた合金を熱処理する
ことにより、１種以上の希土類酸化物Ｒ’ｍＯｎ及び／又は希土類元素Ｒ’’とＢとの複合酸化物を含み、残部がＲ−Ｔ−Ｂ合金及び／又はＲ−Ｔ−Ｍ−Ｂ合金であることを特徴とする高比電気抵抗性希土類磁石を得ることができる。
【００１４】
ここで、ＲはＹを含む希土類元素の１種以上であり、具体的にはＹ，Ｌａ，Ｃｅ，Ｐｒ，Ｎｄ，Ｓｍ，Ｅｕ，Ｇｄ，Ｔｂ，Ｄｙ，Ｈｏ，Ｅｒ，Ｔｍ，Ｙｂ，Ｌｕから選ばれる。ＴはＦｅ及び／又はＣｏ、ＭはＡｌ，Ｓｉ，Ｔｉ，Ｖ，Ｃｒ，Ｃｕ，Ｚｒ，Ｎｂ，Ｍｏ，Ｔａ，Ｗ，Ｇａ，Ｓｎより選ばれる。
【００１５】
Ｒ’はＹを含む希土類元素の１種以上であり、具体的にはＹ，Ｌａ，Ｃｅ，Ｐｒ，Ｎｄ，Ｓｍ，Ｅｕ，Ｇｄ，Ｔｂ，Ｄｙ，Ｈｏ，Ｅｒ，Ｔｍ，Ｙｂ，Ｌｕから選ばれる。この場合、ｍ，ｎは、それぞれＣｅの場合１，２又は２，３、Ｐｒの場合２，３又は６，１１、Ｔｂの場合２，３又は４，７であり、その他の元素の場合はいずれも２，３である。Ｒ’’はＹを含む希土類元素の１種以上であり、具体的にはＹ，Ｌａ，Ｃｅ，Ｐｒ，Ｎｄ，Ｓｍ，Ｅｕ，Ｇｄ，Ｔｂ，Ｄｙ，Ｈｏ，Ｅｒ，Ｔｍ，Ｙｂ，Ｌｕから選ばれる。
【００１６】
本発明においては、上記のようにＲ−Ｔ−Ｂ合金及び／又はＲ−Ｔ−Ｍ−Ｂ合金の粉砕時にＢ2Ｏ3粉末を混合、粉砕し、これを磁場中配向成形後、焼結するものであるが、この際、混合したＢ2Ｏ3粉末が焼結処理中に、
▲１▼４５０℃付近でＢ2Ｏ3が溶ける、
▲２▼Ｒ−Ｔ−Ｂ合金及び／又はＲ−Ｔ−Ｍ−Ｂ合金粉末を一様に濡らし包み込む、
▲３▼液体となったＢ2Ｏ3がＲ−Ｔ−Ｂ合金及び／又はＲ−Ｔ−Ｍ−Ｂ合金粉末と反応し還元されて、希土類酸化物Ｒ’ｍＯｎ及び／又は希土類元素Ｒ’’とＢの複合酸化物となる、
▲４▼全ての還元反応が終了した段階で、希土類酸化物Ｒ’ｍＯｎ、希土類元素Ｒ’’とＢの複合酸化物はそのまま磁石中に分散状態で残る、
▲５▼残ったＲ−Ｔ−Ｂ合金及び／又はＲ−Ｔ−Ｍ−Ｂ合金粉末、及びその合金と還元されて生じたＢの合金で液相焼結が起こる
という過程を経ることによって、絶縁体である希土類酸化物Ｒ’ｍＯｎ及び／又は希土類元素Ｒ’’とＢの複合酸化物が、磁性相であるＲ−Ｔ−Ｂ合金及び／又はＲ−Ｔ−Ｍ−Ｂ合金組成物中に均一に分散している高比電気抵抗性希土類磁石が得られる。
【００１７】
以下に、この磁石の製造方法を詳述する。
最初にＲ−Ｔ−Ｂ合金及び／又はＲ−Ｔ−Ｍ−Ｂ合金組成物の粉末を作製する。この合金組成物の粉末は、例えば溶解、鋳造したインゴット合金を粉砕してもよいし、酸化物等から直接還元拡散法を用いて作製してもよい。溶解したものをストリップキャスティング法を用いて急冷した急冷薄帯を粉砕したものでもよい。また、得られた合金を水素化、脱水素化することによって粉砕したものでもよい。更に、二合金法を用いて、主相のＲ2（Ｆｅ，Ｃｏ）14Ｂ相を主に含む主相合金粉末と、希土類リッチ相を含む助剤合金粉末を別々に前記のように作製して、混合したものでもよい。
【００１８】
このＲ−Ｔ−Ｂ合金及び／又はＲ−Ｔ−Ｍ−Ｂ合金粉末中のＲは、Ｙを含む希土類元素の１種以上で、主成分としてＰｒ，Ｎｄを用いることが好ましい。また、Ｒ量全体の０〜２０重量％をＤｙ，Ｔｂで置換することは保磁力の向上に効果がある。入手上の便宜などの理由からＲとして２種以上の混合物（ミッシュメタル、ジジム等）を用いてもよい。なお、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。Ｒは８〜４０原子％を占めることが望ましい。Ｒがこの範囲より少ないと還元に使われるＲが不足し、合金中に粗大なα−Ｆｅが析出することにより保磁力を低下させるおそれがある。また、Ｒがこの範囲より多いと強磁性相である主相のＲ2（Ｆｅ，Ｃｏ）14Ｂ相の存在比が少なくなり、残留磁化を低下させるおそれがある。
【００１９】
Ｒ−Ｔ−Ｂ合金及び／又はＲ−Ｔ−Ｍ−Ｂ合金粉末中のＴは、Ｆｅ及び／又はＣｏであるが、合金中の５０〜８０原子％が好ましい。Ｔがこの範囲より少ないと、強磁性相である主相のＲ2（Ｆｅ，Ｃｏ）14Ｂ相の存在比が少なくなり、残留磁化が低下するおそれがある。一方、Ｔがこの範囲より多いと、合金中に粗大なα−Ｆｅが析出することにより保磁力が低下するおそれがある。
【００２０】
Ｒ−Ｔ−Ｂ合金及び／又はＲ−Ｔ−Ｍ−Ｂ合金粉末中のＢは０．１〜１０原子％が好ましい。前記範囲外では、強磁性相である主相のＲ2（Ｆｅ，Ｃｏ）14Ｂ相の存在比が少なくなり、残留磁化を低下させるおそれがある。
【００２１】
Ｒ−Ｔ−Ｂ合金及び／又はＲ−Ｔ−Ｍ−Ｂ合金粉末中のＲ，Ｔ，Ｂの組成は、上記範囲内で、必要とされる保磁力及び残留磁化に応じて、決めればよい。
【００２２】
Ｒ−Ｔ−Ｍ−Ｂ合金粉末中のＭは、Ａｌ，Ｓｉ，Ｔｉ，Ｖ，Ｃｒ，Ｃｕ，Ｚｒ，Ｎｂ，Ｍｏ，Ｔａ，Ｗ，Ｇａ，Ｓｎのいずれかより選ばれた１又は２以上の元素である。これらの元素は、保磁力を増加させる効果があるが、残留磁化を低下させる。必要とされる保磁力及び残留磁化に応じて、その配合量を決めればよい。
【００２３】
本発明においては、上記Ｒ−Ｔ−Ｂ合金及び／又はＲ−Ｔ−Ｍ−Ｂ合金粉末をＢ2Ｏ3粉末と混合する。Ｂ2Ｏ3粉末の混合量は、０．０００１〜１５重量％、更に好ましくは０．０１〜１０重量％とすることが好ましい。Ｂ2Ｏ3粉末の混合量が少なすぎると、還元されて生じる絶縁体の希土類酸化物Ｒ’ｍＯｎ及び／又は希土類元素Ｒ’’とＢの複合酸化物の量が少なくなって、十分に焼結後の磁石の比電気抵抗を上げることができない場合がある。逆にＢ2Ｏ3粉末の混合量が多すぎると、強磁性相である主相のＲ2（Ｆｅ，Ｃｏ）14Ｂ相の存在比が少なくなり、実用上十分な磁気特性が出ない場合がある。Ｂ2Ｏ3粉末の混合量は、焼結磁石に必要とされる比電気抵抗と磁気特性との兼ね合いで決めればよい。
【００２４】
Ｂ2Ｏ3粉末の平均粒径は０．１μｍ〜５ｍｍが好ましい。粒径が０．１μｍ未満では、酸化物粉末は凝集してしまって、粒径の大きな酸化物粉末を使用した場合と同じ結果になる。一方、５ｍｍを超える粒径のＢ2Ｏ3粉末を使用すると、混合時に希土類合金粉末と十分に分散した状態で混合できないおそれがある。
【００２５】
Ｂ2Ｏ3粉末を前記のような合金組成物粉末に混合後微粉砕し、次に磁場中成形するが、磁場中配向成形の条件は、磁場５〜２０ｋＯｅ、成形圧力３００〜２０００ｋｇｆ／ｃｍ2が好ましい。
【００２６】
次いで磁場中配向成形した圧粉体を焼結する。焼結条件は、Ｎ2、Ａｒ等の不活性雰囲気中又は真空中で、焼結温度は１０００〜１２００℃がよい。焼結温度が１０００℃より低いと、焼結体の密度が十分上がらず、同時に保磁力も上がらない場合がある。焼結温度が１２００℃より高くなると、Ｒ2（Ｆｅ，Ｃｏ）14Ｂ相の融点を超えるため、大きく粒成長し保磁力が下がるおそれがある。
【００２７】
焼結後、更に磁気特性を向上させるために熱処理を行うとよい。この熱処理は、一般に、温度４００〜８００℃、時間０．５〜１０時間で昇温、保持、降温というパターンで行うが、必要に応じてこれを繰り返したり、段階又は連続的に温度を変化させるパターンでもよい。
【００２８】
本発明の焼結磁石には、原料合金のＲ−Ｔ−Ｂ合金及び／又はＲ−Ｔ−Ｍ−Ｂ合金のＢ2Ｏ3粉末への還元反応により生じた、１種以上の希土類酸化物Ｒ’ｍＯｎ及び／又は希土類元素Ｒ’’とＢとの複合酸化物が含まれていて、これが磁石中に一様に分散していることにより、比電気抵抗を上げている。
【００２９】
上記のようにして得られた本発明の希土類磁石は、１種以上の希土類酸化物Ｒ’ｍＯｎ（Ｒ’はＹを含む希土類元素の１種以上で、ｍ，ｎは、それぞれＣｅの場合１，２又は２，３、Ｐｒの場合２，３又は６，１１、Ｔｂの場合２，３又は４，７、その他は全て２，３である）及び／又は希土類元素Ｒ’’（Ｒ’’はＹを含む希土類元素の１種以上）とＢとの複合酸化物を含み、残部がＲ−Ｔ−Ｂ合金（ＲはＹを含む希土類元素の１種以上、ＴはＦｅ及び／又はＣｏ）及び／又はＲ−Ｔ−Ｍ−Ｂ合金（ＲはＹを含む希土類元素の１種以上、ＴはＦｅ及び／又はＣｏ、ＭはＡｌ，Ｓｉ，Ｔｉ，Ｖ，Ｃｒ，Ｃｕ，Ｚｒ，Ｎｂ，Ｍｏ，Ｔａ，Ｗ，Ｇａ，Ｓｎのいずれかより選ばれた１又は２以上の元素）であることを特徴とする高比電気抵抗性希土類磁石であり、上記Ｒ−Ｔ−Ｂ合金及び／又はＲ−Ｔ−Ｍ−Ｂ合金が、Ｎｄ2Ｆｅ14Ｂ型（Ｒ2（Ｆｅ，Ｃｏ）14Ｂ）の結晶構造を持つ相を有するものであり、具体的に合金中におけるＲが８〜２０原子％、Ｂが２〜２５原子％、Ｔ又はＴ＋Ｍが残部であることが好ましい。
【００３０】
更に希土類酸化物Ｒ’ｍＯｎ及び／又は希土類元素Ｒ’’とＢとの複合酸化物の含有量は、合計で０．０００５〜４０重量％、より好ましくは０．５〜３０重量％となるようにするのが好ましい。酸化物の量が０．０００５重量％未満では、量が少なすぎて比電気抵抗を上げる効果を示さない場合があり、４０重量％を超えると、焼結磁石の磁気特性、特に飽和磁化を落とすおそれがある。希土類酸化物Ｒ’ｍＯｎの含有量は、焼結磁石に必要とされる比電気抵抗と磁気特性との兼ね合いで決めればよい。
【００３１】
【実施例】
以下、実施例及び比較例を示し、本発明を具体的に説明するが、本発明は下記の実施例に制限されるものではない。
【００３２】
［実施例１〜１５］
表１に記載の組成となるように金属原料を溶解し、合金インゴットを得た。この合金インゴットを粗粉砕した粉末に、平均粒径約０．５ｍｍのＢ2Ｏ3粉末を全体で表２に記載の重量％になるように様々な割合で混合し、この粉末をジェットミルを用いて微粉砕した。得られた粉末を磁場中配向成形後、Ａｒ雰囲気中で１１００℃で２時間焼結して、焼結磁石を作製した。
【００３３】
表３に得られた焼結磁石の磁気特性、酸化物の含有量、及び四端子法にて測定した比電気抵抗を記す。表３に示されているように、希土類酸化物の添加量の増加により、残留磁束密度は低下するが比電気抵抗が増加する。
【００３４】
また、得られた焼結磁石についてＥＰＭＡを用い、特性Ｘ線分布像を観測した結果、Ｒ−Ｔ−Ｂ合金、Ｒ−Ｔ−Ｍ−Ｂ合金、希土類酸化物Ｒ’ｍＯｎ、希土類元素Ｒ’’とＢとの複合酸化物の存在が確認され、粉末Ｘ線回折ではＲ−Ｔ−Ｂ／Ｒ−Ｔ−Ｍ−ＢのＮｄ2Ｆｅ14Ｂ型の結晶構造を持つ相が確認された。
【００３５】
［比較例１，２］
表１に記載の組成となるように金属原料を溶解し、合金インゴットを得た。Ｂ2Ｏ3粉末を加えないこと以外は、実施例１と同様に操作して、焼結磁石を作製した。
表３に、この焼結磁石の磁気特性、比電気抵抗を記す。
【００３６】
また、得られた焼結磁石についてＥＰＭＡを用い、特性Ｘ線分布像を観測した結果、Ｒ−Ｔ−Ｂ合金、Ｒ−Ｔ−Ｍ−Ｂ合金の存在のみが確認され、粉末Ｘ線回折ではＲ−Ｔ−Ｂ／Ｒ−Ｔ−Ｍ−ＢのＮｄ2Ｆｅ14Ｂ型の結晶構造を持つ相が確認された。
【００３７】
【表１】
【００３８】
【表２】
【表３】
【発明の効果】
本発明によれば、高い保磁力及びモータ等変動する磁界にさらされるような使用条件でも渦電流の発生が抑えられる大きな比電気抵抗を持つ焼結磁石を、低コストで製造できる。[0001]
BACKGROUND OF THE INVENTION
The present invention particularly relates to a high specific resistance rare earth magnet useful in the industrial field of rotating equipment, electronic components, and electrical equipment, and a method for producing the same.
[0002]
[Prior art]
Permanent magnets composed of R (R is one or more of rare earth elements including Y, and the same shall apply hereinafter), Fe, Co, and B, particularly rare earth magnets mainly composed of Nd as R, have high electronic properties. Widely used in the field of electrical equipment industry.
[0003]
For example, in the past, inexpensive ferrite magnets have been mainly used for permanent magnet type rotating devices. However, in recent years, rare earth magnets that are expensive but have high magnetic properties have been used in response to demands for further downsizing and efficiency improvement of rotating equipment. Of the commercially available rare earth magnets, Sm—Co magnets have a high Curie temperature, and therefore the temperature change of the magnetic properties is small. It also has high corrosion resistance and does not require surface treatment. However, since Co is used as a raw material, it is very expensive. On the other hand, Nd-Fe-B magnets have the highest saturation magnetization among permanent magnets and are inexpensive because they do not use Co as a raw material. However, since the Curie temperature is low, the temperature change of the magnetic characteristics is large and the heat resistance is poor. At the same time, the corrosion resistance is also inferior, so depending on the application, an appropriate surface treatment is required.
[0004]
[Problems to be solved by the invention]
Since the rare earth magnet is a metal, the specific electric resistance is as small as about 100 to 200 μΩcm, which is about 1/100 of the specific electric resistance of ferrite, which is an oxide. Accordingly, when the rare earth magnet is used in a rotating device such as a motor while being exposed to a fluctuating magnetic field, a large amount of eddy current generated by electromagnetic induction flows, and the permanent magnet generates heat due to Joule heat caused by the current. When the temperature of the permanent magnet is increased, especially the Nd—Fe—B magnet has a large temperature change in the magnetic characteristics, so that the magnetic characteristics are deteriorated and, as a result, the efficiency of the motor is also lowered.
[0005]
One countermeasure is to increase the coercive force of the magnet. Increasing the coercive force of the magnet increases the heat resistance of the magnet and makes it difficult to cause irreversible demagnetization. In particular, Nd—Fe—B magnets have a large temperature change in magnetic properties due to their low Curie temperature, and various attempts have been made to increase their coercive force.
[0006]
The most effective method for increasing the coercive force is to replace part of R in the main phase R 2 (Fe, Co) 14 B with heavy rare earth such as Dy or Tb, thereby producing anisotropy of magnetocrystalline magnetic properties. It was a way to increase sex. However, with this method, the saturation magnetization of the magnet is reduced, and the cost of the magnet increases because heavy rare earths are very expensive.
[0007]
As a method for suppressing the eddy current, there is a method in which the permanent magnet is divided into small portions and insulated. This method has the effect of reducing the amount of heat generation in inverse proportion to the number of magnet divisions, but increases the cost of magnet processing.
[0008]
Therefore, as a drastic measure against eddy current, attempts have been made to increase the specific electric resistance of the rare earth magnet itself.
[0009]
The specific electric resistance of the Nd-Fe-B rare earth bonded magnet using a resin binder is about 100 times higher than that of the Nd-Fe-B sintered magnet, but when used for a compressor motor such as a refrigerator, The alternative chlorofluorocarbon used as the refrigerant reacts with the resin binder, which causes a problem in solvent resistance. Japanese Patent Laid-Open No. 5-121220 proposes a method for obtaining a full-density magnet by coating bond magnet powder with a ceramic binder by a sol-gel method or the like and then directly compressing and energizing in a molding die. ing. This method requires heating above the glass transition temperature (about 500 ° C.) of the ceramic binder when curing the magnet, so that the magnetic powder deteriorates due to reaction with the binder, etc., and is sufficient for practical use. It is difficult to achieve both magnetic characteristics and high specific resistance. Japanese Patent Laid-Open No. 10-32427 proposes a method for binding bonded magnet powder at a lower temperature using a liquid inorganic binder, but it is difficult to provide practically sufficient magnetic properties and high specific resistance. It is. In JP-A-9-186010 and JP-A-10-163055, a rare earth magnet powder is mixed with an alkali metal or alkaline earth metal fluoride and / or oxide which does not react with a rare earth magnet with an insulator, and then densified. Thus, a method for obtaining a high specific resistance magnet has been proposed. In this method, in order to obtain a high specific electric resistance, a considerable amount of an insulator must be added, and the volume of the rare earth magnet phase is greatly reduced and the magnetization is lowered. It is difficult to achieve both. Japanese Patent Application Laid-Open No. 11-329809 proposes a method of suppressing heat generation due to Joule heat by laminating layers having high electrical resistivity in the magnetization direction and increasing only the specific electrical resistance of the portion where eddy current flows by the skin effect. ing. This is effective when the direction of fluctuation of the external magnetic field is parallel to the magnetization direction of the magnet, but is not effective when the direction is constantly shifted as in an actual motor.
[0010]
Accordingly, it is an object of the present invention to provide a high specific resistance rare earth magnet having both high specific resistance and sufficient magnetic properties, and a method for manufacturing the same.
[0011]
Means for Solving the Problem and Embodiment of the Invention
The present inventors have studied and studied various methods for obtaining a rare earth element / iron / boron sintered magnet having both high specific electric resistance and sufficient magnetic properties. As a result, R-T-B alloy [R is one or more of rare earth elements including Y (hereinafter the same), T is Fe and / or Co (hereinafter the same)] and / or R-T-M-B alloy [ M is one or more elements selected from Al, Si, Ti, V, Cr, Cu, Zr, Nb, Mo, Ta, W, Ga, and Sn (the same shall apply hereinafter)] ingot alloy or rapid cooling In the step of pulverizing the ribbon, one or more rare earth oxides R′mOn [R ′ is a rare earth element containing Y] by mixing and pulverizing the B 2 O 3 powder, orientation molding in a magnetic field, and sintering. M and n are 1, 2 or 2, 3 for Ce, 2, 3 or 6, 11 for Pr, 2, 3 or 4, 7 for Tb, and all others are 2, 3 (hereinafter the same)] and / or rare earth element R ″ [R ″ is one or more rare earth elements including Y (hereinafter the same) ] And B, and the remainder is an RTB alloy and / or RTMB-alloy alloy. The present invention was completed after confirmation.
[0012]
That is, the present invention
(1) one or more rare earth oxides R'mOn及BiNozomi earth element R '' and includes a composite oxide of B, with a remainder is R-T-B alloy and / or R-T-M-B A high specific electric resistance rare earth magnet characterized by being an alloy, and
(2) In the step of pulverizing the R-T-B alloy and / or the R-T-M-B alloy ingot alloy or the quenched ribbon, the B 2 O 3 powder is mixed and pulverized, and after orientation molding in a magnetic field, There is provided a method for producing a high specific electric resistance rare earth magnet characterized by sintering at a temperature of 1000 to 1200 ° C.
[0013]
Hereinafter, the present invention will be described in detail.
According to the present invention,
(1) In the step of pulverizing an R-T-B alloy and / or an R-T-M-B alloy ingot alloy or a quenched ribbon, B 2 O 3 powder is mixed and pulverized, and after orientation molding in a magnetic field, Sintering (2) If necessary, the obtained alloy is heat-treated to contain one or more rare earth oxides R′mOn and / or a complex oxide of rare earth elements R ″ and B, with the balance being R A high specific resistance rare earth magnet characterized by being a -T-B alloy and / or a R-T-MB alloy can be obtained.
[0014]
Here, R is one or more of rare earth elements including Y. Specifically, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu Chosen from. T is selected from Fe and / or Co, and M is selected from Al, Si, Ti, V, Cr, Cu, Zr, Nb, Mo, Ta, W, Ga, and Sn.
[0015]
R ′ is one or more rare earth elements including Y, and specifically selected from Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. It is. In this case, m and n are 1, 2 or 2, 3 for Ce, 2, 3 or 6, 11 for Pr, 2, 3 or 4, 7 for Tb, and for other elements. Both are 2,3. R ″ is one or more of rare earth elements including Y, specifically from Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. To be elected.
[0016]
In the present invention, the B 2 O 3 powder is mixed and pulverized at the time of crushing the R-T-B alloy and / or R-T-M-B alloy as described above, and this is sintered after orientation molding in a magnetic field. At this time, the mixed B 2 O 3 powder is subjected to the sintering process.
(1) B 2 O 3 dissolves at around 450 ° C.
(2) Wet and wrap the RTB alloy and / or RTMB alloy powder uniformly.
(3) The liquid B 2 O 3 reacts with the RTB alloy and / or RTMB alloy powder and is reduced, and the rare earth oxide R′mOn and / or the rare earth element R ′ is reduced. It becomes a complex oxide of 'and B.
(4) When all the reduction reactions are completed, the rare earth oxide R′mOn and the complex oxide of the rare earth elements R ″ and B remain in a dispersed state in the magnet.
(5) By undergoing a process in which liquid phase sintering occurs in the remaining R-T-B alloy and / or R-T-M-B alloy powder, and the alloy of B reduced by the alloy, In the R-T-B alloy and / or R-T-M-B alloy composition in which the rare earth oxide R′mOn and / or the complex oxide of the rare earth elements R ″ and B as the insulator is a magnetic phase. Thus, a high specific electric resistance rare earth magnet that is uniformly dispersed can be obtained.
[0017]
Below, the manufacturing method of this magnet is explained in full detail.
First, powder of an R-T-B alloy and / or a R-T-M-B alloy composition is prepared. The alloy composition powder may be obtained by, for example, pulverizing a melted and cast ingot alloy, or may be produced directly from an oxide or the like using a reduction diffusion method. What melt | dissolved what was rapidly cooled using the strip casting method and grind | pulverized the thin ribbon may be sufficient. Moreover, what was grind | pulverized by hydrogenating and dehydrogenating the obtained alloy may be used. Further, using the two-alloy method, the main phase alloy powder mainly containing the main phase R 2 (Fe, Co) 14 B phase and the auxiliary alloy powder containing the rare earth-rich phase were separately prepared as described above. It may be mixed.
[0018]
R in this R-T-B alloy and / or R-T-M-B alloy powder is one or more of rare earth elements including Y, and it is preferable to use Pr and Nd as main components. Further, replacing 0 to 20% by weight of the entire R amount with Dy and Tb is effective in improving the coercive force. For reasons such as availability, two or more kinds of mixtures (such as misch metal and didymium) may be used as R. Note that R may not be a pure rare earth element, and may contain impurities that are inevitable in production within a commercially available range. R preferably occupies 8 to 40 atomic%. When R is less than this range, R used for reduction is insufficient, and coarse α-Fe may precipitate in the alloy, which may reduce coercivity. On the other hand, if R exceeds this range, the abundance ratio of the main phase, R 2 (Fe, Co) 14 B phase, which is a ferromagnetic phase, decreases, and there is a possibility that the residual magnetization is lowered.
[0019]
T in the R-T-B alloy and / or R-T-M-B alloy powder is Fe and / or Co, but 50 to 80 atomic% in the alloy is preferable. If T is less than this range, the abundance ratio of the R 2 (Fe, Co) 14 B phase of the main phase, which is a ferromagnetic phase, decreases, and the residual magnetization may decrease. On the other hand, if T is larger than this range, the coercive force may decrease due to precipitation of coarse α-Fe in the alloy.
[0020]
B in the R-T-B alloy and / or R-T-M-B alloy powder is preferably 0.1 to 10 atomic%. Outside the above range, the abundance ratio of the R 2 (Fe, Co) 14 B phase of the main phase, which is a ferromagnetic phase, decreases, and there is a possibility that the residual magnetization is lowered.
[0021]
The composition of R, T, and B in the R-T-B alloy and / or R-T-M-B alloy powder may be determined in accordance with the required coercive force and remanent magnetization within the above range. .
[0022]
M in the R-T-M-B alloy powder is one or more selected from any one of Al, Si, Ti, V, Cr, Cu, Zr, Nb, Mo, Ta, W, Ga, and Sn. Elements. These elements have the effect of increasing the coercive force, but reduce the residual magnetization. The blending amount may be determined according to the required coercive force and residual magnetization.
[0023]
In the present invention, the RTB alloy and / or RTMB alloy powder is mixed with the B 2 O 3 powder. The mixing amount of the B 2 O 3 powder is preferably 0.0001 to 15% by weight, more preferably 0.01 to 10% by weight. If the mixing amount of the B 2 O 3 powder is too small, the amount of the rare earth oxide R′mOn and / or the complex oxide of the rare earth element R ″ and B, which is generated by reduction, is reduced, so In some cases, the specific electrical resistance of the magnet after concatenation cannot be increased. On the other hand, if the amount of B 2 O 3 powder mixed is too large, the abundance ratio of the R 2 (Fe, Co) 14 B phase as the main phase, which is a ferromagnetic phase, will decrease, and practically sufficient magnetic properties will not be obtained. There is. The mixing amount of the B 2 O 3 powder may be determined based on the balance between specific electric resistance and magnetic characteristics required for the sintered magnet.
[0024]
The average particle size of the B 2 O 3 powder is preferably 0.1 μm to 5 mm. When the particle size is less than 0.1 μm, the oxide powder is aggregated, and the same result as when the oxide powder having a large particle size is used is obtained. On the other hand, when a B 2 O 3 powder having a particle diameter exceeding 5 mm is used, there is a possibility that it cannot be mixed in a state sufficiently dispersed with the rare earth alloy powder during mixing.
[0025]
The B 2 O 3 powder is mixed with the alloy composition powder as described above and then finely pulverized and then molded in a magnetic field. The conditions for orientation molding in the magnetic field are as follows: magnetic field 5-20 kOe, molding pressure 300-2000 kgf / cm 2. Is preferred.
[0026]
Next, the green compact oriented in the magnetic field is sintered. The sintering condition is in an inert atmosphere such as N 2 or Ar or in vacuum, and the sintering temperature is preferably 1000 to 1200 ° C. If the sintering temperature is lower than 1000 ° C., the density of the sintered body may not be sufficiently increased, and the coercive force may not be increased at the same time. When the sintering temperature is higher than 1200 ° C., the melting point of the R 2 (Fe, Co) 14 B phase is exceeded, so there is a possibility that the grains grow large and the coercive force decreases.
[0027]
After sintering, heat treatment may be performed to further improve the magnetic properties. This heat treatment is generally performed in a pattern of temperature rise, hold, and temperature drop at a temperature of 400 to 800 ° C. for a time of 0.5 to 10 hours, but this is repeated as necessary or the temperature is changed stepwise or continuously. It may be a pattern.
[0028]
The sintered magnet of the present invention includes one or more rare earth oxides produced by a reduction reaction of a raw alloy R-T-B alloy and / or a R-T-M-B alloy to a B 2 O 3 powder. A composite oxide of R′mOn and / or rare earth elements R ″ and B is contained, and this is uniformly dispersed in the magnet, thereby increasing the specific electric resistance.
[0029]
The rare earth magnet of the present invention obtained as described above is one or more rare earth oxides R′mOn (R ′ is one or more rare earth elements including Y, and m and n are each 1 in the case of Ce. , 2 or 2, 3, Pr is 2, 3 or 6, 11, Tb is 2, 3 or 4, 7 and the others are all 2, 3) and / or rare earth element R '' (R '' Includes a complex oxide of B and one or more rare earth elements including Y), and the balance is an R-T-B alloy (R is one or more rare earth elements including Y, and T is Fe and / or Co). And / or R-T-M-B alloy (R is one or more of rare earth elements including Y, T is Fe and / or Co, M is Al, Si, Ti, V, Cr, Cu, Zr, Nb, 1 or 2 elements selected from Mo, Ta, W, Ga, and Sn). Ri, the R-T-B alloy and / or R-T-M-B alloy, those having a phase having a crystal structure of Nd 2 Fe 14 B type (R 2 (Fe, Co) 14 B) Specifically, it is preferable that R in the alloy is 8 to 20 atomic%, B is 2 to 25 atomic%, and T or T + M is the balance.
[0030]
Furthermore, the total content of the rare earth oxide R′mOn and / or the complex oxide of the rare earth element R ″ and B is 0.0005 to 40% by weight, more preferably 0.5 to 30% by weight. Is preferable. If the amount of the oxide is less than 0.0005% by weight, the amount may be too small to show the effect of increasing the specific electrical resistance. If the amount exceeds 40% by weight, the magnetic properties of the sintered magnet, particularly the saturation magnetization, is reduced. There is a fear. The content of the rare earth oxide R′mOn may be determined based on the balance between the specific electric resistance required for the sintered magnet and the magnetic characteristics.
[0031]
【Example】
EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example.
[0032]
[Examples 1 to 15]
The metal raw material was melted so as to have the composition shown in Table 1 to obtain an alloy ingot. The powder the alloy ingot was coarsely pulverized, mixed with whole B 2 O 3 powder having an average particle diameter of about 0.5mm in various proportions such that the weight% shown in Table 2, the powder jet mill Used and pulverized. The obtained powder was orientation-molded in a magnetic field and then sintered in an Ar atmosphere at 1100 ° C. for 2 hours to produce a sintered magnet.
[0033]
Table 3 shows the magnetic properties, oxide content, and specific electric resistance measured by the four probe method of the sintered magnets obtained. As shown in Table 3, as the amount of rare earth oxide added increases, the residual magnetic flux density decreases but the specific electrical resistance increases.
[0034]
Moreover, as a result of observing a characteristic X-ray distribution image of the obtained sintered magnet using EPMA, an RTB alloy, an RTMB alloy, a rare earth oxide R′mOn, a rare earth element R ′ The presence of a complex oxide of 'and B was confirmed, and powder X-ray diffraction confirmed a phase having an Nd 2 Fe 14 B type crystal structure of RTB / RTMB-B.
[0035]
[Comparative Examples 1 and 2]
The metal raw material was melted so as to have the composition shown in Table 1 to obtain an alloy ingot. A sintered magnet was produced in the same manner as in Example 1 except that B 2 O 3 powder was not added.
Table 3 shows the magnetic properties and specific electrical resistance of this sintered magnet.
[0036]
Moreover, as a result of observing the characteristic X-ray distribution image using EPMA for the obtained sintered magnet, only the presence of the R-T-B alloy and the R-T-M-B alloy was confirmed. A phase having an Nd 2 Fe 14 B type crystal structure of R-T-B / R-T-M-B was confirmed.
[0037]
[Table 1]
[0038]
[Table 2]
[Table 3]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the sintered magnet with a large specific electrical resistance which can suppress generation | occurrence | production of an eddy current can be manufactured at low cost under the use conditions which are exposed to a variable magnetic field, such as a high coercive force and a motor.
Claims (8)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000250597A JP4371188B2 (en) | 2000-08-22 | 2000-08-22 | High specific electric resistance rare earth magnet and method for manufacturing the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000250597A JP4371188B2 (en) | 2000-08-22 | 2000-08-22 | High specific electric resistance rare earth magnet and method for manufacturing the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2002064010A JP2002064010A (en) | 2002-02-28 |
| JP4371188B2 true JP4371188B2 (en) | 2009-11-25 |
Family
ID=18740142
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2000250597A Expired - Fee Related JP4371188B2 (en) | 2000-08-22 | 2000-08-22 | High specific electric resistance rare earth magnet and method for manufacturing the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP4371188B2 (en) |
Families Citing this family (22)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004031781A (en) | 2002-06-27 | 2004-01-29 | Nissan Motor Co Ltd | Rare earth magnet, its manufacturing method and motor using the same |
| CN100550219C (en) * | 2003-03-12 | 2009-10-14 | 日立金属株式会社 | R-T-B is sintered magnet and manufacture method thereof |
| JP4374962B2 (en) | 2003-03-28 | 2009-12-02 | 日産自動車株式会社 | Rare earth magnet and manufacturing method thereof, and motor using rare earth magnet |
| CN100545959C (en) | 2003-08-12 | 2009-09-30 | 日立金属株式会社 | R-T-B is sintered magnet and rare earth alloy |
| JP4238114B2 (en) * | 2003-11-07 | 2009-03-11 | 株式会社日立製作所 | Powder for high resistance rare earth magnet and method for producing the same, rare earth magnet and method for producing the same, rotor for motor and motor |
| JP2005159053A (en) * | 2003-11-26 | 2005-06-16 | Tdk Corp | Method for manufacturing r-t-b-based permanent magnet |
| JP4525072B2 (en) * | 2003-12-22 | 2010-08-18 | 日産自動車株式会社 | Rare earth magnet and manufacturing method thereof |
| JP4234581B2 (en) * | 2003-12-25 | 2009-03-04 | 株式会社日立製作所 | Rare earth magnet, manufacturing method thereof and motor |
| JP4534553B2 (en) * | 2004-03-30 | 2010-09-01 | Ｔｄｋ株式会社 | R-T-B system sintered magnet and manufacturing method thereof |
| JP4766453B2 (en) * | 2005-03-16 | 2011-09-07 | Ｔｄｋ株式会社 | Rare earth permanent magnet |
| US7919200B2 (en) | 2005-06-10 | 2011-04-05 | Nissan Motor Co., Ltd. | Rare earth magnet having high strength and high electrical resistance |
| US7988795B2 (en) | 2005-12-02 | 2011-08-02 | Shin-Etsu Chemical Co., Ltd. | R-T-B—C rare earth sintered magnet and making method |
| JP2009118619A (en) * | 2007-11-06 | 2009-05-28 | Honda Motor Co Ltd | Permanent magnet for motor |
| JP5115511B2 (en) * | 2008-03-28 | 2013-01-09 | Ｔｄｋ株式会社 | Rare earth magnets |
| CN104952574A (en) | 2014-03-31 | 2015-09-30 | 厦门钨业股份有限公司 | Nd-Fe-B-Cu type sintered magnet containing W |
| CN105321647B (en) * | 2014-07-30 | 2018-02-23 | 厦门钨业股份有限公司 | The preparation method of rare-earth magnet quick cooling alloy and rare-earth magnet |
| CN106756416A (en) * | 2016-12-05 | 2017-05-31 | 钦州市钦南区生产力促进中心 | A kind of rare earth alloy composite and preparation method thereof |
| JP6702215B2 (en) * | 2017-02-02 | 2020-05-27 | 日立金属株式会社 | R-T-B system sintered magnet |
| JP6819328B2 (en) * | 2017-02-03 | 2021-01-27 | 株式会社豊田中央研究所 | Magnetic powder and its manufacturing method |
| CN107293386A (en) * | 2017-06-29 | 2017-10-24 | 成都磁动势科技有限公司 | Resistant to elevated temperatures magnetic material |
| CN107731438A (en) * | 2017-10-31 | 2018-02-23 | 桂林市漓江机电制造有限公司 | A kind of rare earth permanent-magnetic material and preparation method thereof |
| CN108389671A (en) * | 2017-12-27 | 2018-08-10 | 宁波招宝磁业有限公司 | A kind of high corrosion-resistant neodymium iron boron magnetic body and preparation method thereof |
-
2000
- 2000-08-22 JP JP2000250597A patent/JP4371188B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JP2002064010A (en) | 2002-02-28 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP4371188B2 (en) | High specific electric resistance rare earth magnet and method for manufacturing the same | |
| EP0134304B1 (en) | Permanent magnets | |
| EP0134305B1 (en) | Permanent magnet | |
| JP2751109B2 (en) | Sintered permanent magnet with good thermal stability | |
| EP0302947B1 (en) | Rare earth element-iron base permanent magnet and process for its production | |
| WO2015020182A1 (en) | R-t-b type sintered magnet, and motor | |
| JP4951703B2 (en) | Alloy material for RTB-based rare earth permanent magnet, method for manufacturing RTB-based rare earth permanent magnet, and motor | |
| JP2727507B2 (en) | Permanent magnet and manufacturing method thereof | |
| JP4700578B2 (en) | Method for producing high resistance rare earth permanent magnet | |
| JPH01219143A (en) | Sintered permanent magnet material and its production | |
| JP2787580B2 (en) | Nd-Fe-B based sintered magnet with excellent heat treatment | |
| JP5743458B2 (en) | Alloy material for RTB-based rare earth permanent magnet, method for manufacturing RTB-based rare earth permanent magnet, and motor | |
| JPH06207203A (en) | Production of rare earth permanent magnet | |
| JPH11251125A (en) | Rare-earth-iron-boron sintered magnet and its manufacture | |
| US5230749A (en) | Permanent magnets | |
| JP2008223052A (en) | Rare earth magnet alloy, method for manufacturing thin strip of rare earth magnet alloy, and bond magnet | |
| JPH06302417A (en) | Permanent magnet and its manufacture | |
| JPH0678582B2 (en) | Permanent magnet material | |
| JPH03170643A (en) | Alloy for permanent magnet | |
| JPS6077959A (en) | Permanent magnet material and its manufacture | |
| JPH0536494B2 (en) | ||
| JPH089752B2 (en) | Method for manufacturing R1R2FeCoB-based permanent magnet | |
| JPH0475303B2 (en) | ||
| JPH04143221A (en) | Production of permanent magnet | |
| JP3703903B2 (en) | Anisotropic bonded magnet |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20060713 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20080730 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20080820 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20081014 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20090812 |
|
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120911 Year of fee payment: 3 |
|
| R150 | Certificate of patent or registration of utility model |
Free format text: JAPANESE INTERMEDIATE CODE: R150 Ref document number: 4371188 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20090825 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20150911 Year of fee payment: 6 |
|
| LAPS | Cancellation because of no payment of annual fees |