JP3643214B2

JP3643214B2 - Method for producing laminated permanent magnet

Info

Publication number: JP3643214B2
Application number: JP18782397A
Authority: JP
Inventors: 裕和金清; 哲広沢
Original assignee: Neomax Co Ltd
Current assignee: Proterial Ltd
Priority date: 1997-06-26
Filing date: 1997-06-26
Publication date: 2005-04-27
Anticipated expiration: 2017-06-26
Also published as: JPH1116715A

Description

【０００１】
【発明の属する技術分野】
この発明は、各種小型モーター、アクチュエーター、磁気センサー用磁気回路に最適な永久磁石の製造方法に係り、６ａｔ％以下の希土類元素と１５ａｔ％〜３０ａｔ％のホウ素を含む特定組成の溶湯を、特定の溶湯急冷条件により、高靭性を有し、加工が容易な平均厚み１０μｍ〜１００μｍのアモルファス薄帯を作製し、この薄帯の表面にはんだなどの金属層を設けた後、このアモルファス薄帯をそのままあるいは所望形状になるよう切断もしくは打ち抜き加工した後、任意の肉厚となるように積層して、平均結晶粒径が１０ｎｍ〜５０ｎｍになる結晶化熱処理を施こすことによって、金属層を溶融させて一体化し、ｉＨｃ≧２ｋＯｅ，Ｂｒ≧８ｋＧの硬磁気特性を有し、２０μｍ以上の任意の肉厚を有する所望形状の永久磁石を製造する積層永久磁石の製造方法に関する。
【０００２】
【従来の技術】
現在、家電用機器、ＯＡ機器、電装品等において、一層の高性能化と小型化が要求される用途においては、従来のハードフェライト磁石に代わり、磁気特性に優れる希土類焼結磁石を所望の形状に切断、研削加工するか、あるいは希土類ボンド磁石を所望形状に成形するなどして対応している。
【０００３】
切削・加工法にて作製された真密度の永久磁石は高性能であるものの、材料の種類を問わず、既存のハードフェライト磁石に対して著しく高価となる欠点がある。さらに、加工肉厚は０．２ｍｍ程度が限度であり、それ以下のものは製造困難である。
【０００４】
一方、ボンド磁石においては、直径３ｍｍ、肉厚０．３ｍｍ程度の扁平磁石が成形され、時計用小型ステッピングモータ用永久磁石として用いられているが、粉末粒径が５０μｍ〜３００μｍ程度の磁粉を樹脂と共に加圧成形するため、極薄い、例えば０．１ｍｍ以下の肉厚を有す成形品を得ることは困難である。特にリング磁石では肉厚と直角方向にパンチで圧縮する方法では肉厚０．８ｍｍ程度が限界である。
【０００５】
また、圧縮方向に長い寸法の磁石を成形する場合は、磁粉とダイス表面との摩擦抵抗のために圧力が均一に伝わらなくなり、薄肉の長尺品の成形は困難である。最近、ボンド磁石を押し出し成形法により、肉厚０．５ｎｍ厚の長尺リング磁石の製造が可能となったとの報告があるが、樹脂比率の分だけ磁気特性は低下し、最高でも残留磁束密度Ｂｒは７ｋＧ、最大エネルギー積（ＢＨ）ｍａｘは９．９ＭＧＯｅ程度である。
【０００６】
ボンド磁石用磁粉としては、従来から２：１７系Ｓｍ−Ｃｏ合金粉末が用いられているが、最近ではＨＤＤＲ法により製造されるＮｄ‐Ｆｅ‐Ｂ系の合金粉末もボンド磁石用磁粉として用いられつつある。これらは、いずれもボンド磁石用として開発された磁粉であり、これら自体に加工を施し、永久磁石とすることはできない。
【０００７】
また、現在、ボンド磁石粉としては溶湯急冷法にて製造されるＮｄ‐Ｆｅ‐Ｂ系の等方性磁粉が多く使用されているが、この材料は溶湯急冷により結晶質からなる薄片（フレーク）として得られるため、極めて脆く、弾性的に曲げる、打ち抜き加工を施すなどして任意の形状とすることは不可能であり、ボンド磁石磁粉としての用途に限られる。
【０００８】
また、ボンド磁石は焼結磁石に必要な切削加工なしに任意形状を得られるため低コスト化を計れるが、樹脂を介して平均粒径１５０μｍ程度のＮｄ−Ｆｅ‐Ｂ磁粉が結合しているため、磁粉が脱粉しやすく、例えば、ＨＤＤ用モーターに使用した場合は、脱粉により記録媒体を損傷する危険性が高く、表面塗装など脱粉防止のための対策をとる必要がある。
【０００９】
さらに、Ｎｄ‐Ｆｅ‐Ｂ磁粉の急冷合金薄帯を粉砕した粉砕粉であるため、粉砕粉の破断面は急冷薄帯面に比べ活性で酸化しやすく、酸化防止のための表面塗装を施さなければ、８０℃、相対湿度９０％の環境下では１０００時間放置すると、酸化の影響により、パーミアンス係数Ｐｅが１の磁石の場合、磁束密度が２％程度低下するだけでなく、表面に赤錆が発生し脱粉の原因となる。
【００１０】
【発明が解決しようとする課題】
一方、Ｎｄ‐Ｆｅ‐Ｂ系磁石において、近年、Ｎｄ₄Ｆｅ₇₇Ｂ₁₉（ａｔ％）近傍組成でＦｅ₃Ｂ型化合物を主相とする磁石材料が提案（Ｒ．Ｃｏｅｈｏｏｒｎ等、Ｊ．ｄｅＰｈｙｓ，Ｃ８，１９８８，６６９〜６７０頁）され、その技術内容は米国特許４，９３５，０７４号等に開示されている。また、Ｋｏｏｎはそれよりも以前に、Ｌａを必須元素として含むＬａ‐Ｒ‐Ｂ‐Ｆｅアモルファス合金に結晶化熱処理を施すことによる、微細結晶からなる永久磁石の製造方法を米国特許４，４０２，７７０号にて提案している。
【００１１】
最近ではＲｉｃｈｔｅｒらによってＥＰＰａｔｅｎｔ５５８６９１Ｂ１に開示されているように、Ｎｄを３．８ａｔ％〜３．９ａｔ％含有するＮｄ‐Ｆｅ‐Ｂ‐Ｖ‐Ｓｉ合金溶湯を回転するＣｕロール上に噴射して得られたアモルファスフレークを７００℃で熱処理することにより、硬磁気特性を有す薄片が得られることを報告している。これらの永久磁石材料は、厚み２０μｍ〜６０μｍのアモルファスフレークに結晶化熱処理を施すことによって得られる、軟磁性であるＦｅ₃Ｂ相と硬磁性であるＲ₂Ｆｅ₁₄Ｂ相が混在する結晶集合組織を有する準安定構造の永久磁石材料である。
【００１２】
かかる永久磁石材料は、１０ｋＧ程度のＢｒと２ｋＯｅ〜３ｋＯｅのｉＨｃを有し、高価なＮｄの合有濃度が４ａｔ％程度と低いため、配合原料価格はＮｄ₂Ｆｅ₁₄Ｂを主相とするＮｄ‐Ｆｅ‐Ｂ磁石より安価であり、価格対性能比の点で従来の希土類磁石より優れ、ハードフェライト磁石の代替材料として提案されたが、従来のＮｄ₂Ｆｅ₁₄Ｂを主相とするＮｄ−Ｆｅ‐Ｂボンド磁石同様、ボンド磁石としての用途に限られてきた。
【００１３】
しかしながら、ボンド磁石は磁気特性の高い磁粉を用いても、磁粉の充填率を８０％以上にすることは困難なため、ボンド磁石として高い磁気特性は期待できず、特に小型のボンド磁石の場合は等方性で１０ＭＧＯｅ程度が最高である。
【００１４】
この発明は特定組成の合金溶湯を特定の溶湯急冷条件により得られたアモルファス薄帯に、平均結晶粒径が１０ｎｍ〜５０ｎｍになる結晶化熱処理を施こすことによって、ｉＨｃ≧２ｋＯｅ、Ｂｒ≧８ｋＧの硬磁気特性を有する微細結晶型永久磁石を製造できることに着目し、ボンド磁石より高い磁気特性を有効に利用できるよう、これを任意の肉厚を有する所望形状、例えば、加速度センサー用磁気回路に最適な小型、薄肉形状の永久磁石を容易に製造できる永久磁石の製造方法の提供を目的としている。
【００１５】
【課題を解決するための手段】
発明者らは、ボンド磁石より高い磁気特性を有し、任意の肉厚を有する所望形状に加工できる永久磁石を目的に種々検討した結果、６ａｔ％以下の希土類元素と１５ａｔ％〜３０ａｔ％のホウ素を含む特定組成の合金溶湯より、特定の溶湯急冷条件にて得られた平均厚み１０μｍ〜１００μｍのアモルファス組織からなる急冷合金薄帯が優れた靭性および弾性変形能を有することに注目して、この薄帯の表面にはんだなどの金属層を設けた後、急冷合金薄帯をそのままあるいは所定の長さに切断または任意形状に打ち抜き加工した後、これを二枚以上積層して所要厚みとなし、結晶化熱処理による磁気的硬化処理を行い、ｉＨｃ≧２ｋＯｅ，Ｂｒ≧８ｋＧの硬磁気特性を有する永久磁石となすと同時に溶融させたはんだで永久磁石薄帯同士を密着、一体化することで、粉砕、ボンド磁石化の方法を用いることなく、任意の肉厚、所望形状を有する積層永久磁石を得られることを知見し、この発明を完成した。
【００１６】
すなわち、この発明は、組成式を
Ｆｅ_100-x-yＲ_xＡ_y
（Ｆｅ_1-mＣｏ_m）_100-x-yＲ_xＡ_y
Ｆｅ_100-x-y-zＲ_xＡ_yＭ_z
（Ｆｅ_1-mＣｏ_m）_100-x-y-zＲ_xＡ_yＭ_z
（但しＲはＰｒ、Ｎｄ、Ｄｙ、Ｔｂの１種または２種以上、ＡはＣ、Ｂの１種または２種、ＭはＡｌ、Ｓｉ、Ｔｉ、Ｖ、Ｃｒ、Ｎｎ、Ｎｉ、Ｃｕ、Ｇａ、Ｚｒ、Ｎｂ、Ｍｏ、Ａｇ、Ｈｆ、Ｔａ、Ｗ、Ｐｔ、Ａｕ、Ｐｂの１種または２種以上）のいずれかで表し、組成範囲を限定する記号ｘ、ｙ、ｚ、ｍが下記値を満足する合金溶湯を、３０ｋＰａ以下の不活性ガス雰囲気中において、回転ロールを用いた溶湯急冷法により得られる、９０％以上アモルファス組織からなる、優れた靭性および弾性変形能を有し、平均厚みが１０μｍ〜１００μｍの急冷合金薄帯を作製した後、急冷合金薄帯の表面に２００℃〜５５０℃の融点を有する金属を鍍金もしくは蒸着し、そのままあるいは切断または打ち抜き加工により所定形状とした後、これを任意の厚みになるよう二枚以上積層し、その後、アモルファス組織から、Ｆｅ ₃ Ｂ相とＮｄ ₂ Ｆｅ ₁₄ Ｂ相が混在する平均結晶粒径が１０ｎｍ〜５０ｎｍになる結晶化熱処温度５５０℃〜７５０℃にて結晶化熱処理を施こす際、同時に薄帯表面に鍍金もしくは蒸着した金属が溶融し、薄帯同士が密着することにより、２０μｍ以上の任意の肉厚を有する積層永久磁石の製造方法を提案するものである。
１≦ｘ＜６ａｔ％
１５≦ｙ≦３０ａｔ％
０．０１≦ｚ≦７ａｔ％
０．００１≦ｍ≦０．５
【００１７】
【発明の実施の形態】
組成の限定理由
希土類元素Ｒは、Ｐｒ、ＮｄまたはＤｙ、Ｔｂの１種または２種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、例えばＣｅ、ＬａではｉＨｃが２ｋＯｅ以上の特性が得られず、また、ＴｂおよびＤｙを除くＳｍ以降の中希土類元素、重希土類元素は磁気特性の劣化を招来するため好ましくない。Ｒは、１ａｔ％未満では２ｋＯｅ以上のｉＨｃが得られず、また６ａｔ％を越えると８ｋＧ以上のＢｒが得られないため、１ａｔ％以上、６ａｔ％未満の範囲とする。好ましくは、２ａｔ％〜５．５ａｔ％が良い。
【００１８】
Ａは、ＣまたはＢの１種または２種の合計が１５ａｔ％未満では液体急冷後の金属組織において、α‐Ｆｅの析出が著しく、保磁力の発現に必須であるＮｄ₂Ｆｅ₁₄Ｂ型結晶構造を有する化合物の析出が阻害されるため、１ｋＯｅ未満のｉＨｃしか得られず、また、３０ａｔ％を越えると減磁曲線の角形性が著しく低下するため、１５ａｔ％〜３０ａｔ％の範囲とする。好ましくは、１５ａｔ％〜２０ａｔ％が良い。
【００１９】
Ｆｅは、上述の元素の含有残余を占め、Ｆｅの一部をＣｏで置換することにより金属組織が微細化され、減磁曲線の角形性が改善され、最大エネルギー積（ＢＨ）ｍａｘの向上、並びに耐熱性の向上が得られるが、Ｆｅに対する置換量が０．１％未満ではかかる効果が得られず、また、５０％を越えると８ｋＧ以上のＢｒが得られないため、ＣｏのＦｅに対する置換量は０．１％〜５０％の範囲とする。好ましくは、０．５％〜１０％の置換量が良い。
【００２０】
添加元素ＭのＡｌ、Ｓｉ、Ｔｉ、Ｖ、Ｃｒ、Ｍｎ、Ｎｉ、Ｃｕ、Ｇａ、Ｚｒ、Ｎｂ、Ｍｏ、Ａｇ、Ｈｆ、Ｔａ、Ｗ、Ｐｔ、Ａｕ、Ｐｂは、微細結晶永久磁石の微細組織化に寄与し、保磁力を改善すると共に、減磁曲線の角形性を改善し、Ｂｒおよび（ＢＨ）ｍａｘを増大する効果が得られるが、０．０１ａｔ％未満ではかかる効果が得られず、７ａｔ％以上では、Ｂｒ≧８ｋＧの磁気特性を得られないため、０．０１ａｔ％〜７ａｔ％の範囲とする。好ましくは、０．０５ａｔ％〜５ａｔ％である。
【００２１】
製造条件の限定理由
この発明において、上述の特定組成の合金溶湯を３０ｋＰａ以下の不活性ガス雰囲気中、回転ロールを用いた溶湯急冷法にて、優れた靭性および弾性変形能を有す、平均厚みが１０μｍ〜１００μｍであるアモルファス薄帯を作製し、このアモルファス薄帯を任意の形状に加工した後、平均結晶粒径が１０ｎｍ〜５０ｎｍになる結晶化熱処理を施こすことによって、ｉＨｃ≧２ｋＯｅ，Ｂｒ≧８ｋＧの硬磁気特性を有し、平均厚み１０μｍ〜１００μｍの肉厚である任意形状の薄肉の永久磁石を得ることが最も重要である。
【００２２】
すなわち、合金溶湯の急冷雰囲気が３０ｋＰａ以上の場合は、回転ロールと合金溶湯の間に巻き込まれる雰囲気ガスの影響が顕著になるため、実質９０％以上アモルファスからなる均一組織とならないため、優れた靭性および弾性変形能が得られず、任意の形状に急冷合金薄帯の加工できないため、好ましくない。雰囲気ガスは、合金溶湯の酸化防止のため、不活性ガス雰囲気とする。好ましくは、Ａｒ雰囲気中が良い。
【００２３】
合金溶湯の溶湯急冷に用いる回転ロールの材質は、熱伝導度の点からアルミニウム合金、純銅および銅合金、鉄、真鍮、タングステン、青銅を採用できるが、機械的強度および経済性の点から、ＣｕもしくはＦｅ（但しＣｕ、Ｆｅを含む合金でもよい）が好ましく、上記以外の材質では熱伝導が悪いため、充分合金溶湯を冷却できず、実質９０％以上アモルファスからなる均一組織を得られないため好ましくない。
【００２４】
回転ロールを用いた溶湯急冷法としては、単ロール急冷法、および双ロール急冷法が挙げられるが、優れた靭性および弾性変形能を有す、平均厚みが１０μｍ〜１００μｍのアモルファス薄帯を作製できれば、いずれの急冷方法を採用しても良い。
【００２５】
例えば、回転ロールに中心線粗さＲａ≦０．８μｍ、最大高さＲｍａｘ≦８．２μｍ、１０点の平均粗さＲｚ≦３．２μｍの表面粗度を有するＣｕ製ロールを用いた単ロール急冷法を採用した場合、ロール周速度が１０ｍ／ｓ以下の場合、破損せずに曲げることのできる臨界半径が１０ｍｍ以下である優れた靭性および弾性変形能を有す平均厚み１０μｍ〜１００μｍのアモルファス薄帯が得られないため、ロール周速度は１０ｍ／ｓ以上が好ましい。好ましいロール周速度は１５ｍ／ｓ〜５０ｍ／ｓである。
【００２６】
この発明において、２０μｍ以上の任意の肉厚を有する永久磁石は以下の製造工程による。上述の溶湯急冷条件により得られた優れた靭性および弾性変形能を有する平均厚みが１０μｍ〜１００μｍのアモルファス組織からなる急冷合金薄帯に、５５０℃以下にて溶融する金属を鍍金もしくは蒸着した後、この急冷合金薄帯を任意の厚みになるよう二枚以上積層し、その後、平均結晶粒径が１０ｎｍ〜５０ｎｍになる結晶化熱処温度５５０℃〜７５０℃にて結晶化熱処理を施こす際、同時に薄帯表面に鍍金もしくは蒸着した金属層が溶融することによって、この薄帯同士を密着、一体化させることによって得られる。
【００２７】
急冷合金薄帯に鍍金もしくは蒸着する金属は、このアモルファス薄帯の結晶化温度である５５０℃〜６００℃以下の融点を有する金属であればよいが、人体および環境に対する影響、取り扱いの容易さを鑑み、Ｚｎ、はんだが好ましい。また、鍍金もしくは蒸着する金属量は、永久磁石に占める割合が１０ｗｔ％以上の場合、８ｋＧ以上のＢｒが得られないため好ましくなく、また、０．０１ｗｔ％以下では積層した永久磁石薄帯を密着できないため、金属量は０．０１ｗｔ％〜１０ｗｔ％に限定する。好ましくは０．５ｗｔ％〜５ｗｔ％が良い。
【００２８】
所望形状の積層永久磁石は、上述の鍍金もしくは蒸着した急冷合金薄帯を切断あるいは打ち抜き加工した後、任意の厚みになるよう二枚以上積層し、その後、平均結晶粒径が１０ｎｍ〜５０ｎｍになる結晶化熱処理を施こす際、同時に鍍金もしくは蒸着した金属層が溶融し、加工済みの急冷合金薄帯同士を密着、一体化させることによって得られる。
【００２９】
アモルファス薄帯を切断あるいは打ち抜き加工により任意形状とする際は、結晶化熱処理後の薄帯では靭性および弾性変形能が失われるため、パンチ等を用いた機械的打ち抜き加工は、薄帯が破断し任意形状に打ち抜けないため、優れた靭性および弾性変形能を有しているアモルファス薄帯を任意形状に打ち抜き加工した後、結晶化熱処理を行う方法が好ましい。なお、超音波加工などの機械的打ち抜き、加工以外の方法であれば、結晶化後熱処理を加えた後でも破断等の問題なく加工を行える。
【００３０】
前述の９０％以上がアモルファス組織からなる急冷合金薄帯は、ｉＨｃ≧２ｋＯｅ、Ｂｒ≧８ｋＧの硬磁気特性を発現し得る平均結晶粒径１０ｎｍ〜５０ｎｍの微細結晶金属組織となるよう、結晶化熱処理を行なう必要があるが、熱処理温度が５５０℃未満では保磁力の発現に必須なＮｄ₂Ｆｅ₁₄Ｂが析出しないため１ｋＯｅ未満のｉＨｃしか得られない、また７５０℃を越えると粒成長が著しく、平均結晶粒径が５０ｎｍ以上となるためｉＨｃ、Ｂｒおよび減磁曲線の角形性が劣化し、上述の磁気特性が得られないため、熱処理温度は５５０℃〜７５０℃が好ましい。ただし、５５０℃〜７５０℃の熱処理にて得られる微細結晶組織において、平均結晶粒径は細かいほど好ましいが、１０ｎｍ未満ではｉＨｃの低下を引き起こすため、下限を１０ｎｍとする。
【００３１】
熱処理において、雰囲気は酸化を防ぐためＡｒガス、Ｎ₂ガスなどの不活性ガス雰囲気中もしくは１．３３Ｐａ以下の真空中が好ましい。磁気特性は熱処理時間には依存しないが、６時間を越えるような場合、若干時間の経過とともにＢｒが低下する傾向があるため、好ましくは６時間未満が良い。
【００３２】
【実施例】
表１のＮｏ．１〜２０の組成となるように、純度９９．５％以上のＦｅ、Ｃｏ、Ｃ、Ａｌ、Ｓｉ、Ｔｉ、Ｖ、Ｃｒ、Ｍｎ、Ｎｉ、Ｃｕ、Ｇａ、Ｚｒ、Ｎｂ、Ｍｏ、Ａｇ、Ｐｔ、Ａｕ、Ｐｂ、Ｂ、Ｎｄ、Ｐｒ、Ｄｙ、Ｔｂの金属を用い、総量が３０ｇとなるように秤量し、底部に０．３ｍｍ×８ｍｍのスリットを有する石英るつぼ内に投入し、表１の急冷雰囲気圧に保持したＡｒ雰囲気中で高周波加熱により溶解した。
【００３３】
合金の溶解温度を１３００℃にした後、合金湯面をＡｒガスにより加圧して室温にて、表１に示す急冷雰囲気およびロール周速度にて回転するＣｕ製ロールの外周面に０．７ｍｍの高さから溶湯を連続して鋳込み、幅８ｍｍ、平均厚み１０μｍ〜１００μｍの連続した急冷合金薄帯を作製した。得られた急冷合金薄帯は、粉末ＸＲＤ回折の結果、いずれもアモルファスであることを確認した。表２に得られた急冷合金薄帯の平均厚みを示す。
【００３４】
この連続した急冷合金薄帯を切断し、幅８ｍｍ、長さ５０ｍｍの急冷薄帯にした後、純度９９．９％のＺｎを０．１５μｍ／ｍｉｎの成膜速度にて、厚み４μｍになるよう急冷薄帯に蒸着した。その後、このＺｎを蒸着した急冷薄帯を５ｍｍ×５ｍｍのパンチによる打ち抜き加工により、５ｍｍ×５ｍｍの面を有す急冷合金薄片とした後、平均厚み０．２ｍｍとなるように積層し、その後、Ａｒ流気中、表１に示す熱処理温度で１０分間保持した後、室温まで冷却し、薄帯同士が溶融したＺｎにより密着した５ｍｍ×５ｍｍ×０．２ｍｍの永久磁石を作製した。
【００３５】
磁石の磁気特性は永久磁石の高さ方向（５ｍｍ×５ｍｍ面に対して垂直）に６０ｋＯｅのパルス着磁磁界で着磁した後、ＢＨトレーサーにて閉磁路で評価した。表３に磁石特性を示す。なお、Ｎｏ．３〜Ｎｏ．２０において、Ｃｏ、Ａｌ、Ｓｉ、Ｔｉ、Ｖ、Ｃｒ、Ｍｎ、Ｎｉ、Ｃｕ、Ｇａ、Ｚｒ、Ｎｂ、Ｍｏ、Ａｇ、Ｐｔ、Ａｕ、Ｐｂは各構成相のＦｅの一部を置換していることを確認した。図１にＮｏ．２の結晶化熱処理前後の粉末Ｘ線回折パターンを示す。
【００３６】
【表１】

【００３７】
【表２】

【００３８】
【表３】

【００３９】
【発明の効果】
この発明は、６ａｔ％以下の希土類元素と１５ａｔ％〜３０ａｔ％のホウ素を含む特定組成の合金溶湯を特定の溶湯急冷条件により、高靭性を有し、加工が容易な平均厚み１０μｍ〜１００μｍのアモルファス組織からなる急冷合金薄帯を作製した後、この急冷合金薄帯の表面に５５０℃以下の融点をもつ金属層を鍍金もしくは蒸着により形成し、その後、所望形状になるよう切断もしくは打ち抜き加工した後、任意の厚みになるよう急冷合金薄帯を二枚以上積層し、ｉＨｃ≧２ｋＯｅ、Ｂｒ≧８ｋＧの硬磁気特性を得られる、アモルファス組織からＦｅ ₃ Ｂ相とＮｄ ₂ Ｆｅ ₁₄ Ｂ相が混在する平均結晶粒径１０ｎｍ〜５０ｎｍになる温度５５０℃〜７５０℃にて結晶化熱処理を施こすことで、同時に急冷合金薄帯表面に設けた金属層が溶融させてこの薄帯同士を強固に結合することで、粉砕、ボンド磁石化の方法を用いることなく、また成形後、切削加工を施す必要のない、任意の肉厚、所望形状を有する高性能な積層永久磁石を容易に提供できる。
【００４０】
また、この発明によって得られた積層磁石は、急冷合金薄帯を粉砕せずに用いるため、既存のＮｄ‐Ｆｅ‐Ｂ系ボンド磁石の問題点であった酸化、および脱粉の問題を改善できるだけでなく、ボンド磁石以上の密度が得られることから高い磁気特性を有し、家電用機器、ＯＡ機器、電装品等の小型高性能化に貢献できる。
【図面の簡単な説明】
【図１】急冷合金薄帯の結晶化熱処理前後の粉末Ｘ線回折パターンを示すグラフである。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a permanent magnet most suitable for a magnetic circuit for various small motors, actuators, and magnetic sensors. A specific composition of a molten metal containing a rare earth element of 6 at% or less and 15 at% to 30 at% of boron is specified. An amorphous ribbon having an average thickness of 10 μm to 100 μm, which has high toughness and is easy to process, is prepared under molten metal quenching conditions, and a metal layer such as solder is provided on the surface of the ribbon. Alternatively, after cutting or punching into a desired shape, the layers are laminated to have an arbitrary thickness, and subjected to crystallization heat treatment with an average crystal grain size of 10 nm to 50 nm, thereby melting the metal layer. Integrated to produce a permanent magnet with a desired shape having hard magnetic properties of iHc ≧ 2 kOe, Br ≧ 8 kG, and an arbitrary thickness of 20 μm or more. The method for producing a layer permanent magnets.
[0002]
[Prior art]
Currently, in applications where higher performance and miniaturization are required in home appliances, OA equipment, electrical equipment, etc., instead of conventional hard ferrite magnets, rare earth sintered magnets with excellent magnetic properties are in the desired shape. It is possible to cope with this by cutting, grinding, or forming a rare earth bonded magnet into a desired shape.
[0003]
Although a true density permanent magnet manufactured by a cutting / processing method has high performance, it has a drawback that it is extremely expensive compared to existing hard ferrite magnets regardless of the type of material. Furthermore, the processed wall thickness is limited to about 0.2 mm, and a thickness less than that is difficult to manufacture.
[0004]
On the other hand, in the bonded magnet, a flat magnet having a diameter of about 3 mm and a thickness of about 0.3 mm is formed and used as a permanent magnet for a small stepping motor for a watch. However, magnetic powder having a powder particle size of about 50 μm to 300 μm is used as a resin. In addition, since it is pressure molded together, it is difficult to obtain a molded product that is extremely thin, for example, having a thickness of 0.1 mm or less. Particularly in the case of a ring magnet, a thickness of about 0.8 mm is the limit in the method of compressing with a punch in a direction perpendicular to the thickness.
[0005]
Further, when a magnet having a long dimension in the compression direction is formed, pressure is not uniformly transmitted due to frictional resistance between the magnetic powder and the die surface, and it is difficult to form a thin long product. Recently, it has been reported that long ring magnets with a thickness of 0.5 nm can be manufactured by extrusion molding of bonded magnets. However, the magnetic properties are reduced by the resin ratio, and the maximum residual magnetic flux density. Br is 7 kG, and the maximum energy product (BH) max is about 9.9 MGOe.
[0006]
Conventionally, 2:17 series Sm-Co alloy powder has been used as magnetic powder for bonded magnets, but Nd-Fe-B type alloy powder produced by the HDDR method has recently been used as magnetic powder for bonded magnets. It's getting on. These are all magnetic particles developed for bonded magnets, and cannot be processed into permanent magnets.
[0007]
At present, many Nd-Fe-B isotropic magnetic powders produced by the melt quenching method are used as bonded magnet powders, but this material is made of crystalline flakes by flake quenching (flakes). Therefore, it is extremely brittle and cannot be formed into an arbitrary shape by bending elastically, punching, or the like, and is limited to use as a bonded magnet magnetic powder.
[0008]
In addition, bond magnets can be manufactured at any cost without the need for cutting processing for sintered magnets, but the cost can be reduced. However, Nd-Fe-B magnetic particles having an average particle size of about 150 μm are bonded through a resin. For example, when used in an HDD motor, there is a high risk of damage to the recording medium due to powder removal, and it is necessary to take measures to prevent powder removal such as surface coating.
[0009]
Furthermore, because it is a pulverized powder obtained by pulverizing a quenched alloy ribbon of Nd-Fe-B magnetic powder, the fracture surface of the pulverized powder is more active and oxidizable than the quenched ribbon surface, and surface coating must be applied to prevent oxidation. For example, if the magnet with a permeance coefficient Pe of 1 is left for 1000 hours in an environment of 80 ° C. and 90% relative humidity, not only the magnetic flux density is reduced by about 2% but also red rust is generated on the surface. Causes powdering.
[0010]
[Problems to be solved by the invention]
On the other hand, in Nd-Fe-B magnets, a magnet material having a composition close to Nd ₄ Fe ₇₇ B ₁₉ (at%) and having a Fe ₃ B-type compound as a main phase has recently been proposed (R. Cohoern et al., J. de Phys). C8, 1988, pages 669 to 670), and its technical contents are disclosed in US Pat. No. 4,935,074 and the like. Prior to that, Koon disclosed a method for producing a permanent magnet made of fine crystals by subjecting a La—R—B—Fe amorphous alloy containing La as an essential element to crystallization heat treatment. Proposed in 770.
[0011]
Recently, as disclosed by Richter et al. In EP Patent 558691B1, a molten Nd—Fe—B—V—Si alloy containing 3.8 at% to 3.9 at% of Nd is injected onto a rotating Cu roll. It has been reported that flakes having hard magnetic properties can be obtained by heat-treating the obtained amorphous flakes at 700 ° C. These permanent magnet materials are obtained by subjecting amorphous flakes having a thickness of 20 μm to 60 μm to a crystallization heat treatment, and a crystalline texture in which a soft magnetic Fe ₃ B phase and a hard magnetic R ₂ Fe ₁₄ B phase are mixed. A metastable permanent magnet material having
[0012]
Such a permanent magnet material has Br of about 10 kG and iHc of 2 kOe to 3 kOe, and the combined concentration of expensive Nd is as low as about 4 at%. Therefore, the blended raw material price is Nd with Nd ₂ Fe ₁₄ B as the main phase. -It is cheaper than Fe-B magnets, is superior to conventional rare earth magnets in terms of price-performance ratio, and has been proposed as an alternative material for hard ferrite magnets, but Nd--conventional Nd ₂ Fe ₁₄ B as the main phase Like the Fe-B bonded magnet, it has been limited to use as a bonded magnet.
[0013]
However, even if magnetic powder with high magnetic properties is used as a bonded magnet, it is difficult to make the filling rate of magnetic particles 80% or more, so high magnetic properties cannot be expected as a bonded magnet, especially in the case of a small bonded magnet. Isotropic and 10 MGOe is the best.
[0014]
In the present invention, an alloy ribbon having a specific composition is subjected to a crystallization heat treatment with an average crystal grain size of 10 nm to 50 nm on an amorphous ribbon obtained under specific melt quenching conditions, whereby iHc ≧ 2 kOe, Br ≧ 8 kG. Focusing on the ability to manufacture fine crystal type permanent magnets with hard magnetic properties, this is ideal for desired shapes with arbitrary wall thickness, for example, magnetic circuits for acceleration sensors, so that higher magnetic properties than bonded magnets can be used effectively An object of the present invention is to provide a method of manufacturing a permanent magnet that can easily manufacture a small, thin-walled permanent magnet.
[0015]
[Means for Solving the Problems]
As a result of various studies for the purpose of a permanent magnet having higher magnetic characteristics than a bonded magnet and capable of being processed into a desired shape, the inventors have found that a rare earth element of 6 at% or less and 15 at% to 30 at% of boron. from molten alloy having a specific composition containing, by focusing on having toughness and elasticity deformability thin-strip rapidly solidified alloy with excellent made of an amorphous structure with an average thickness 10μm~100μm obtained similar matter particular melt-quenching conditions, After a metal layer such as solder is provided on the surface of the ribbon, the quenched alloy ribbon is cut as it is or cut into a predetermined length or punched into an arbitrary shape, and two or more of these are laminated to obtain the required thickness. Then, a magnetic hardening process is performed by crystallization heat treatment to obtain a permanent magnet having hard magnetic properties of iHc ≧ 2 kOe, Br ≧ 8 kG, and at the same time, the permanent magnet ribbons are densely bonded with the molten solder. It was found that by laminating and integrating, a laminated permanent magnet having an arbitrary thickness and a desired shape can be obtained without using methods of pulverization and bond magnetization, and the present invention has been completed.
[0016]
That is, in the present invention, the composition formula is Fe _100-xy R _x A _y.
_{_{(Fe 1-m Co m)}} 100-xy R x A y
Fe _100-xyz R _x A _y M _z
_{_{(Fe 1-m Co m)}} 100-xyz R x A y M z
(However, R is one or more of Pr, Nd, Dy, Tb, A is one or two of C, B, M is Al, Si, Ti, V, Cr, Nn, Ni, Cu, Ga. , Zr, Nb, Mo, Ag, Hf, Ta, W, Pt, Au, or Pb), and the symbols x, y, z, and m that limit the composition range are the following values: the molten alloy satisfying the, in the following in an inert gas atmosphere 30 kPa, obtainable by melt-quenching method using a rotating roll, consisting of 90% amorphous structure, possess excellent toughness and elasticity deformability, average thickness After forming a quenched alloy ribbon having a thickness of 10 μm to 100 μm, a metal having a melting point of 200 ° C. to 550 ° C. is plated or vapor-deposited on the surface of the quenched alloy ribbon, and is formed into a predetermined shape as it is or by cutting or punching. This any Two or more layers are laminated so as to have a thickness, and then, from an amorphous structure , a crystallization heat treatment temperature of 550 ° C. to 750 ° C. at which the average crystal grain size in which the Fe ₃ B phase and the Nd ₂ Fe ₁₄ B phase are mixed is 10 nm to 50 nm. Proposing a method for manufacturing laminated permanent magnets with an optional wall thickness of 20 μm or more by performing metallization heat treatment at the same time as the plated or vapor deposited metal melts on the surface of the ribbon and the ribbons adhere to each other. To do.
1 ≦ x <6at%
15 ≦ y ≦ 30at%
0.01 ≦ z ≦ 7at%
0.001 ≦ m ≦ 0.5
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Reasons for limiting composition Rare earth element R can obtain high magnetic properties only when it contains one or two kinds of Pr, Nd or Dy, Tb in a specific amount. For other rare earth elements such as Ce and La, iHc is 2 kOe or more. In addition, medium rare earth elements and heavy rare earth elements after Sm excluding Tb and Dy are not preferable because they cause deterioration of magnetic characteristics. If R is less than 1 at%, iHc of 2 kOe or more cannot be obtained, and if it exceeds 6 at%, Br of 8 kG or more cannot be obtained, so the range is set to 1 at% or more and less than 6 at%. Preferably, 2 at% to 5.5 at% is good.
[0018]
A is a Nd ₂ Fe ₁₄ B type crystal in which α-Fe precipitates remarkably in the metal structure after liquid quenching when the total of one or two of C or B is less than 15 at%, and is essential for the expression of coercive force. Since precipitation of the compound having a structure is inhibited, only iHc of less than 1 kOe can be obtained, and when it exceeds 30 at%, the squareness of the demagnetization curve is remarkably deteriorated, so the range is set to 15 at% to 30 at%. Preferably, 15 at% to 20 at% is good.
[0019]
Fe accounts for containing residual aforementioned elements, the metallic structure by replacing a part of Fe with Co is miniaturized, an improved squareness of the demagnetization curve, improving maximum energy product (BH) max, In addition, although the heat resistance can be improved, such an effect cannot be obtained if the substitution amount with respect to Fe is less than 0.1%, and when it exceeds 50%, Br of 8 kG or more cannot be obtained. The amount is in the range of 0.1% to 50%. A substitution amount of 0.5% to 10% is preferable.
[0020]
The additive elements M, Al, Si, Ti, V, Cr, Mn, Ni, Cu, Ga, Zr, Nb, Mo, Ag, Hf, Ta, W, Pt, Au, and Pb are the microstructure of the microcrystalline permanent magnet In addition to improving coercive force and improving the squareness of the demagnetization curve, the effect of increasing Br and (BH) max is obtained. If it is 7 at% or more, the magnetic characteristics of Br ≧ 8 kG cannot be obtained, so the range is 0.01 at% to 7 at%. Preferably, it is 0.05 at% to 5 at%.
[0021]
Reason for limitation of production conditions In this invention, the average thickness of the molten alloy having the above specific composition is excellent in toughness and elastic deformability in a molten metal quenching method using a rotating roll in an inert gas atmosphere of 30 kPa or less. An amorphous ribbon having a thickness of 10 μm to 100 μm is manufactured, processed to an arbitrary shape, and then subjected to a crystallization heat treatment to an average crystal grain size of 10 nm to 50 nm, whereby iHc ≧ 2 kOe, Br It is most important to obtain an arbitrarily shaped thin permanent magnet having hard magnetic properties of ≧ 8 kG and an average thickness of 10 μm to 100 μm.
[0022]
That is, when the quenching atmosphere of the molten alloy is 30 kPa or more, the influence of the atmosphere gas caught between the rotating roll and the molten alloy becomes remarkable, so that it does not become a uniform structure composed substantially of amorphous material by 90% or more. In addition, the elastic deformability cannot be obtained, and the quenched alloy ribbon cannot be processed into an arbitrary shape. The atmosphere gas is an inert gas atmosphere to prevent oxidation of the molten alloy. An Ar atmosphere is preferable.
[0023]
Aluminum alloy, pure copper and copper alloy, iron, brass, tungsten, bronze can be adopted as the material of the rotating roll used for the molten metal quenching of the molten alloy, but from the viewpoint of mechanical strength and economy, Cu Or Fe (although it may be an alloy containing Cu or Fe) is preferable, and since heat conduction is poor with materials other than the above, the molten alloy cannot be cooled sufficiently, and a uniform structure consisting of substantially 90% or more cannot be obtained. Absent.
[0024]
Examples of the melt quenching method using a rotating roll include a single roll quenching method and a twin roll quenching method. If an amorphous ribbon having an excellent toughness and elastic deformability and an average thickness of 10 μm to 100 μm can be produced, Any quenching method may be adopted.
[0025]
For example, single roll quenching using a roll made of Cu having a surface roughness of center line roughness Ra ≦ 0.8 μm, maximum height Rmax ≦ 8.2 μm, 10-point average roughness Rz ≦ 3.2 μm as a rotating roll. When the roll speed is 10 m / s or less when the method is adopted, an amorphous thin film with an average thickness of 10 μm to 100 μm having excellent toughness and elastic deformability that has a critical radius of 10 mm or less that can be bent without breakage. Since a band cannot be obtained, the roll peripheral speed is preferably 10 m / s or more. A preferable roll peripheral speed is 15 m / s to 50 m / s.
[0026]
In the present invention, a permanent magnet having an arbitrary thickness of 20 μm or more is based on the following manufacturing process. After plating or vapor-depositing a metal that melts at 550 ° C. or lower onto a quenched alloy ribbon having an amorphous structure with an average thickness of 10 μm to 100 μm having excellent toughness and elastic deformability obtained by the above-described molten metal quenching conditions, When two or more of the quenched alloy ribbons are laminated to have an arbitrary thickness and then subjected to a crystallization heat treatment at a crystallization heat treatment temperature of 550 ° C. to 750 ° C. so that the average crystal grain size becomes 10 nm to 50 nm, At the same time, the metal layer deposited or vapor-deposited on the surface of the ribbon is melted so that the ribbons are brought into close contact with each other and integrated.
[0027]
Metal plating or vapor deposition on the quenched alloy ribbon, may be any metal that have a 550 ° C. to 600 ° C. below the melting point which is the crystallization temperature of the amorphous ribbon, the influence on the human body and the environment, ease of handling In view of this, Zn and solder are preferable. Further, the amount of plating or vapor deposition is not preferable when the proportion of the permanent magnet is 10 wt% or more because Br of 8 kG or more cannot be obtained, and 0.01 wt% or less is not preferable. Therefore, the amount of metal is limited to 0.01 wt % to 10 wt %. Preferably 0.5 wt%-5 wt% is good.
[0028]
A laminated permanent magnet having a desired shape is obtained by cutting or stamping the above-described plating or vapor-deposited quenched alloy ribbon, and then laminating two or more sheets to have an arbitrary thickness, and then the average crystal grain size becomes 10 nm to 50 nm. when straining facilities crystallization heat treatment, plating or vapor-deposited metal layer is melted at the same time, contact the processed rapidly solidified alloy thin entrained workers can be obtained by integrating.
[0029]
When an amorphous ribbon is cut or punched into a desired shape, the toughness and elastic deformability are lost in the ribbon after crystallization heat treatment. Therefore, mechanical punching using a punch or the like breaks the ribbon. In order to prevent punching into an arbitrary shape, a method of performing a crystallization heat treatment after punching an amorphous ribbon having excellent toughness and elastic deformability into an arbitrary shape is preferable. If the method is other than mechanical punching and processing such as ultrasonic processing, the processing can be performed without problems such as fracture even after the heat treatment after crystallization.
[0030]
The quenching alloy ribbon comprising 90% or more of the amorphous structure described above is subjected to a crystallization heat treatment so as to have a fine crystalline metal structure with an average crystal grain size of 10 nm to 50 nm that can exhibit hard magnetic properties of iHc ≧ 2 kOe and Br ≧ 8 kG. However, when the heat treatment temperature is less than 550 ° C., Nd ₂ Fe ₁₄ B essential for coercive force expression does not precipitate, so only iHc less than 1 kOe can be obtained. Since the average crystal grain size is 50 nm or more, the squareness of iHc, Br, and demagnetization curve is deteriorated, and the above magnetic characteristics cannot be obtained. Therefore, the heat treatment temperature is preferably 550 ° C. to 750 ° C. However, in the fine crystal structure obtained by heat treatment at 550 ° C. to 750 ° C., the average crystal grain size is preferably as fine as possible, but if it is less than 10 nm, iHc is lowered, so the lower limit is 10 nm.
[0031]
In the heat treatment, the atmosphere is preferably in an inert gas atmosphere such as Ar gas or N ₂ gas or in a vacuum of 1.33 Pa or less in order to prevent oxidation. The magnetic properties do not depend on the heat treatment time, but when it exceeds 6 hours, Br tends to decrease with the passage of time, so the time is preferably less than 6 hours.
[0032]
【Example】
No. in Table 1 Fe, Co, C, Al, Si, Ti, V, Cr, Mn, Ni, Cu, Ga, Zr, Nb, Mo, Ag, Pt having a purity of 99.5% or more so as to have a composition of 1 to 20 , Au, Pb, B, Nd, Pr, Dy, Tb, were weighed so that the total amount was 30 g, and placed in a quartz crucible having a slit of 0.3 mm × 8 mm at the bottom, It melt | dissolved by the high frequency heating in Ar atmosphere hold | maintained at the quenching atmospheric pressure.
[0033]
After the melting temperature of the alloy is 1300 ° C., the surface of the molten alloy is pressurized with Ar gas at room temperature, 0.7 mm on the outer peripheral surface of the Cu roll rotating at the quenching atmosphere and the roll peripheral speed shown in Table 1. The molten metal was continuously cast from the height, and a continuously quenched alloy ribbon having a width of 8 mm and an average thickness of 10 μm to 100 μm was produced. The obtained quenched alloy ribbon was confirmed to be amorphous as a result of powder XRD diffraction. Table 2 shows the average thickness of the quenched alloy ribbon obtained.
[0034]
After cutting this continuous quenched alloy ribbon into a quenched ribbon with a width of 8 mm and a length of 50 mm, Zn with a purity of 99.9% is formed to a thickness of 4 μm at a film formation rate of 0.15 μm / min. Vapor deposited on a quenched ribbon. Then, after quenching the thin ribbon on which this Zn was vapor-deposited into a quenched alloy flake having a surface of 5 mm × 5 mm by punching with a 5 mm × 5 mm punch, it was laminated to an average thickness of 0.2 mm, and then After maintaining for 10 minutes at the heat treatment temperature shown in Table 1 in an Ar stream, a 5 mm × 5 mm × 0.2 mm permanent magnet was produced in which the ribbons were in close contact with the molten Zn.
[0035]
The magnetic properties of the magnet were evaluated in a closed magnetic circuit with a BH tracer after magnetizing with a 60 kOe pulse magnetizing field in the height direction of the permanent magnet (perpendicular to the 5 mm × 5 mm plane). Table 3 shows the magnet characteristics. In addition, No. 3-No. 20, Co, Al, Si, Ti, V, Cr, Mn, Ni, Cu, Ga, Zr, Nb, Mo, Ag, Pt, Au, and Pb replace a part of Fe of each constituent phase. It was confirmed. In FIG. 2 shows powder X-ray diffraction patterns before and after crystallization heat treatment.
[0036]
[Table 1]

[0037]
[Table 2]

[0038]
[Table 3]

[0039]
【The invention's effect】
The present invention provides an amorphous alloy having an average thickness of 10 μm to 100 μm that has high toughness and is easy to work with an alloy melt having a specific composition containing rare earth elements of 6 at% or less and 15 at% to 30 at% boron under specific melt quenching conditions. After preparing a quenched alloy ribbon comprising a structure, a metal layer having a melting point of 550 ° C. or lower is formed on the surface of the quenched alloy ribbon by plating or vapor deposition, and then cut or punched into a desired shape. Two or more quenching alloy ribbons are laminated so as to have an arbitrary thickness, and hard magnetic properties of iHc ≧ 2 kOe and Br ≧ 8 kG can be obtained. Fe ₃ B phase and Nd ₂ Fe ₁₄ B phase are mixed from amorphous structure By performing crystallization heat treatment at a temperature of 550 ° C. to 750 ° C. at an average crystal grain size of 10 nm to 50 nm, the metal layer provided on the surface of the quenched alloy ribbon is simultaneously melted. High-performance lamination with an arbitrary thickness and desired shape without the need for grinding and bonding magnetization methods or after forming, by firmly bonding the ribbons together A permanent magnet can be easily provided.
[0040]
Further, since the laminated magnet obtained by the present invention is used without pulverizing the quenched alloy ribbon, it can improve the oxidation and degreasing problems that were problems of the existing Nd-Fe-B bond magnets. In addition, since it has a density higher than that of bonded magnets, it has high magnetic properties and can contribute to the miniaturization and high performance of home appliances, OA equipment, electrical equipment, and the like.
[Brief description of the drawings]
FIG. 1 is a graph showing powder X-ray diffraction patterns before and after crystallization heat treatment of a quenched alloy ribbon.

Claims

The composition formula is expressed as Fe _100-xy R _x A _y (where R is one or more of Pr, Nd, Dy, and Tb, A is one or two of C and B), and limits the composition range. A molten alloy in which the symbols x and y satisfy the following values is processed by a molten metal quenching method using a rotating roll in an inert gas atmosphere of 30 kPa or less to produce a quenched alloy ribbon comprising 90% or more of an amorphous structure. Then, a metal having a melting point of 200 ° C. to 550 ° C. is plated or vapor-deposited on the surface of the obtained quenched alloy ribbon having an average thickness of 10 μm to 100 μm, and this quenched ribbon is processed as it is or into a predetermined shape to have a predetermined thickness And heat treatment at 550 ° C. to 750 ° C. for crystallization from an amorphous structure to a fine crystal structure with an average crystal grain size of 10 nm to 50 nm in which Fe ₃ B phase and Nd ₂ Fe ₁₄ B phase are mixed. At the same time table A method for producing a laminated permanent magnet in which a metal layer on a surface is melted to form an integrated permanent magnet.
1 ≦ x <6at%
15 ≦ y ≦ 30at%

The composition formula _{_{(Fe 1-m Co m)}} 100-xy R x A y ( where R is Pr, Nd, Dy, 1 or more kinds of Tb, A is C, 1 or 2 or of B) and The method for producing a laminated permanent magnet according to claim 1, wherein the molten alloy is represented by a symbol x, y, m that limits the composition range and satisfies the following values.
1 ≦ x <6at%
15 ≦ y ≦ 30at%
0.001 ≦ m ≦ 0.5

The composition formula is Fe _100-xyz R _x A _y M _z (where R is one or more of Pr, Nd, Dy, and Tb, A is one or two of C and B, and M is Al, Si, (Ti, V, Cr, Mn, Ni, Cu, Ga, Zr, Nb, Mo, Ag, Hf, Ta, W, Pt, Au, Pb) The method for producing a laminated permanent magnet according to claim 1, wherein a molten alloy in which x, y, and z satisfy the following values is made into a permanent magnet.
1 ≦ x <6at%
15 ≦ y ≦ 30at%
0.01 ≦ z ≦ 7at%

The composition formula _{_{(Fe 1-m Co m)}} 100-xyz R x A y M z ( where R is Pr, Nd, Dy, 1 or more kinds of Tb, A is C, 1 or 2 or of B , M is expressed as Al, Si, Ti, V, Cr, Mn, Ni, Cu, Ga, Zr, Nb, Mo, Ag, Hf, Ta, W, Pt, Au, or Pb). 2. The method for producing a laminated permanent magnet according to claim 1, wherein a molten alloy in which the symbols x, y, z, and m that limit the composition range satisfy the following values is made into a permanent magnet.
1 ≦ x <6at%
15 ≦ y ≦ 30at%
0.01 ≦ z ≦ 7at%
0.01 ≦ m ≦ 0.5