JP2004228283A - Process for producing rare earth magnet powder exhibiting excellent magnetic anisotropy - Google Patents
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Abstract
Description
【０００１】
【発明の属する技術分野】
この発明は、磁気異方性に優れた希土類磁石粉末、特に残留磁束密度の一層優れた希土類磁石粉末の製造方法に関するものである。
【０００２】
【従来の技術】
Ｒ（但し、ＲはＹを含む希土類元素を示す。以下同じ）、Ｍ（但し、ＭはＧａ、Ｚｒ、Ｎｂ、Ｍｏ、Ｈｆ、Ｔａ、Ｗ、Ｎｉ、Ａｌ、Ｔｉ、Ｖ、Ｃｕ、Ｃｒ、Ｇｅ、ＣおよびＳｉの内の１種または２種以上を示す。以下同じ）とすると、原子％で（以下、％は原子％を示す）、Ｒ：１０〜２０％、Ｃｏ：０〜５０％、Ｂ：３〜２０％、Ｍ：０〜５％を含有し、残部がＦｅおよび不可避不純物からなる成分組成を有する希土類磁石合金原料をＡｒガス雰囲気中、温度：６００〜１２００℃に保持して均質化処理し、または均質化処理せずに、水素雰囲気中で室温から温度：５００℃未満までの所定の温度に昇温、または昇温し保持して水素吸収処理したのち、
水素圧力：１０〜１０００ｋＰａの水素雰囲気中で５００〜１０００℃の範囲内の所定の温度に昇温し保持することにより前記希土類磁石合金原料に水素を吸収させて相変態による分解を促す水素吸収・分解処理を施し、
引き続いて、水素吸収・分解処理を施した希土類磁石合金原料を不活性ガス圧：１０〜１０００ｋＰａ、温度：５００〜１０００℃の範囲内の所定の温度で不活性ガス雰囲気中に保持することにより中間熱処理を行い、
さらに引き続いて、必要に応じて、中間熱処理を施した希土類磁石合金原料を５００〜１０００℃の範囲内の所定の温度で、絶対圧：０．６５〜１０ｋＰａ未満の水素雰囲気中または水素分圧：：０．６５〜１０ｋＰａ未満の水素と不活性ガスとの混合ガス雰囲気中に保持することにより希土類磁石合金原料に水素を一部残したまま減圧水素中熱処理を行い、
その後、５００〜１０００℃の範囲内の所定の温度で到達圧：０．１３ｋＰａ以下の真空雰囲気に保持することにより強制的に水素を放出させて相変態を促す脱水素処理を施し、ついで冷却し、粉砕する工程からなる磁気異方性に優れた希土類磁石粉末の製造方法は知られている（特開２０００−２１６１４号公報参照）。
【０００３】
【発明が解決しようとする課題】
近年、電気・電子業界では磁気異方性が一層優れるとともに一層安価な希土類磁石粉末が求められており、一層磁気異方性が優れるとともに一層安価な希土類磁石粉末を効率良く低コストで製造できる方法の研究開発がなされている。
【０００４】
【課題を解決するための手段】
そこで、本発明者らも、一層磁気異方性に優れた希土類磁石粉末を効率良く低コストで製造できる方法を開発すべく研究を行った。その結果、
（ａ）前記従来の磁気異方性に優れた希土類磁石粉末の製造方法における水素吸収・分解処理後に不活性ガスを供給して不活性ガス圧：１０〜１０００ｋＰａ、温度：５００〜１０００℃の範囲内の所定の温度で不活性ガス雰囲気中に保持する中間熱処理に代えて、５００〜１０００℃の範囲内の温度を保持しつつ、水素圧力を水素吸収・分解処理時の水素圧力の２０〜６０％の圧力の水素雰囲気中に保持する中間減圧熱処理を施すと、従来の水素吸収・分解処理後に不活性ガス雰囲気の中間熱処理を施すよりも残留磁束密度が向上する、
（ｂ）この中間減圧熱処理は、水素吸収・分解処理と同じ水素雰囲気であり、水素を排気して圧力を減らすだけであるから、不活性ガスを導入する従来の中間熱処理に比べて操作が簡単であり、量産に適した方法であるとともに、従来の製造方法で製造した希土類磁石粉末に比べて磁気異方性、特に残留磁束密度が一層向上する、という研究結果が得られたのである。
【０００５】
この発明は、かかる研究結果に基づいて成されたものであって、
（１）必要に応じて真空またはＡｒガス雰囲気中、温度：６００〜１２００℃に保持の条件で均質化処理した希土類磁石合金原料を、圧力：１０〜１０００ｋＰａの水素ガス雰囲気中で室温から温度：５００℃未満までの温度に昇温、または昇温し保持することにより水素を吸収させる水素吸収処理を施し、
この水素吸収処理した前記希土類磁石合金原料を圧力：１０〜１０００ｋＰａの水素ガス雰囲気中で５００〜１０００℃の範囲内の温度に昇温し保持することにより前記希土類磁石合金原料にさらに水素を吸収させて分解する水素吸収・分解処理を施し、
引き続いて、水素吸収・分解処理を施した希土類磁石合金原料を５００〜１０００℃の範囲内の温度で、水素吸収・分解処理時の水素圧力の２０〜６０％の圧力の水素雰囲気中に保持する中間減圧熱処理を施し、
その後、５００〜１０００℃の範囲内の温度で到達圧：０．１３ｋＰａ以下の真空雰囲気に保持することにより希土類磁石合金原料から強制的に水素を放出させて相変態を促す脱水素処理を施し、ついで冷却し、粉砕する磁気異方性に優れた希土類磁石粉末の製造方法、
（２）必要に応じて真空またはＡｒガス雰囲気中、温度：６００〜１２００℃に保持の条件で均質化処理した希土類磁石合金原料を圧力：１０〜１０００ｋＰａの水素ガス雰囲気中で室温から温度：５００℃未満までの温度に昇温、または昇温し保持することにより水素を吸収させる水素吸収処理を施し、
この水素吸収処理した前記希土類磁石合金原料を圧力：１０〜１０００ｋＰａの水素ガス雰囲気中で５００〜１０００℃の範囲内の温度に昇温し保持することにより前記希土類磁石合金原料にさらに水素を吸収させて分解する水素吸収・分解処理を施し、
引き続いて、水素吸収・分解処理を施した希土類磁石合金原料を５００〜１０００℃の範囲内の温度で水素吸収・分解処理時の圧力の２０〜６０％の圧力の水素雰囲気中に保持する中間減圧熱処理を施し、
引き続いて、５００〜１０００℃の範囲内の温度で圧力：０．６５〜１３ｋＰａでかつ中間減圧熱処理の圧力よりも低い圧力の水素雰囲気中に保持することにより希土類磁石合金原料に水素を一部残したまま減圧水素中熱処理を行い、
その後、５００〜１０００℃の範囲内の温度で到達圧：０．１３ｋＰａ以下の真空雰囲気に保持することにより希土類磁石合金原料から強制的に水素を放出させて相変態を促す脱水素処理を施し、ついで冷却し、粉砕する磁気異方性に優れた希土類磁石粉末の製造方法、に特徴を有するものである。
【０００６】
この発明で使用する希土類磁石合金原料は、
Ｒ：１０〜２０％、Ｂ：３〜２０％を含有し、残部がＦｅおよび不可避不純物からなる成分組成を有する希土類磁石合金原料、
Ｒ：１０〜２０％、Ｂ：３〜２０％、Ｍ：０．００１〜５％を含有し、残部がＦｅおよび不可避不純物からなる成分組成を有する希土類磁石合金原料、
Ｒ：１０〜２０％、Ｃｏ：０．１〜５０％、Ｂ：３〜２０％を含有し、残部がＦｅおよび不可避不純物からなる成分組成を有する希土類磁石合金原料、または、Ｒ：１０〜２０％、Ｃｏ：０．１〜５０％、Ｂ：３〜２０％、Ｍ：０．００１〜５％を含有し、残部がＦｅおよび不可避不純物からなる成分組成を有する希土類磁石合金原料が好ましい。
【０００７】
次に、この発明で使用する希土類磁石合金原料の成分組成および製造条件を前述の如く限定した理由を説明する。
（Ａ）成分組成
Ｒ（Ｙを含む希土類元素）：
Ｒは、Ｎｄを主体とし、その他、Ｙ、Ｄｙ、Ｐｒ、Ｓｍ、Ｃｅ、Ｌａ、Ｔｂ、Ｅｒ、Ｅｕ、Ｇｄ、Ｔｍ、Ｙｂ、Ｌｕ、Ｈｏなどを微量含む希土類元素であるが、その含有量が１０％未満では保磁力が低下し、一方、２０％を越えて含有すると飽和磁化が低下していずれも希望の磁気特性が得られないので好ましくない。したがって、Ｒの含有量は１０〜２０％に定めた。
【０００８】
Ｂ：
Ｂの含有量は３％未満では保磁力が低下し、一方、２０％を越えて含有すると飽和磁化が低下していずれも希望の磁気特性が得られないので好ましくない。したがって、Ｂの含有量は３〜２０％に定めた。
【０００９】
Ｃｏ：
Ｃｏは希土類磁石合金の等方性化を阻止するために必要に応じて添加するが、その含有量が０．１％未満では所望の効果が得られず、一方、５０％を越えて含有すると、保磁力および飽和磁化が下がるので異方化しても高特性が得られない。したがって、この発明の希土類磁石粉末の製造方法で使用する希土類磁石合金原料に含まれるＣｏの含有量は０．１〜５０％（一層好ましくは、５〜３０％）に定めた。
【００１０】
Ｍ（Ｇａ、Ｚｒ、Ｎｂ、Ｍｏ、Ｈｆ、Ｔａ、Ｗ、Ｎｉ、Ａｌ、Ｔｉ、Ｖ、Ｃｕ、Ｃｒ、Ｇｅ、ＣおよびＳｉの内の１種または２種以上）：
Ｍは、保磁力および残留磁束密度の一層の向上のために必要に応じて添加するが、その含有量が０．００１％未満では所望の効果が得られず、一方、５％を越えて添加すると、保磁力および残留磁束密度が低下するので好ましくない。したがってＭの含有量は０．００１〜５％に定めた。
【００１１】
（Ｂ）製造条件
希土類磁石合金原料は圧力：１０〜１０００ｋＰａの水素ガス雰囲気中で室温から温度：５００℃未満までの所定の温度に昇温、または昇温し５００℃未満までの所定の温度（例えば、１００℃）に保持することにより水素を吸収せしめる水素吸収処理を施す。この希土類磁石合金原料を圧力：１０〜１０００ｋＰａの水素ガス雰囲気中で室温から温度：５００℃未満までの所定の温度に昇温、または昇温する水素吸収処理は、従来から行われている処理である。
【００１２】
この水素吸収処理した希土類磁石合金原料をさらに加熱し、圧力：１０〜１０００ｋＰａの水素ガス雰囲気中で温度：５００〜１０００℃の範囲内の所定の温度に保持する水素吸収・分解処理を施すことにより原料に水素を吸収させて相変態を促し分解させる。この水素吸収・分解処理工程における圧力：１０〜１０００ｋＰａの水素ガス雰囲気中で温度：５００〜１０００℃の範囲内の所定の温度に保持する条件はすでに知られている条件であり、特に新規な条件ではないのでその限定理由の説明は省略する。
【００１３】
かかる水素吸収・分解処理したのち、５００〜１０００℃の範囲内の温度で、水素吸収・分解処理時の水素圧力の２０〜６０％の圧力（具体的には、圧力：２〜６００ｋＰａでかつ水素吸収・分解処理時の水素圧力より相対的に低い圧力）の水素雰囲気中に保持する中間減圧熱処理を施す。この中間減圧熱処理は従来の不活性ガス雰囲気で行なう中間熱処理に代わる処理工程であり、水素吸収・分解処理したのち温度を５００〜１０００℃に保持したまま水素ガスを排気して減圧することにより所定の水素圧力に保持することができるから、不活性ガス雰囲気に交換する必要がなく、簡単な操作で中間減圧熱処理を施すことができ、しかも残留磁束密度を一層高める効果がある。
この中間減圧熱処理における水素圧力を水素吸収・分解処理時の水素圧力の２０〜６０％の圧力にした理由は、水素吸収・分解処理時の水素圧力の２０％未満の圧力に保持すると異方性化の反応速度が速すぎるために保持力が低下してしまうので好ましくなく、一方、水素吸収・分解処理時の水素圧力の６０％より高い水素圧力に保持すると、異方性化の反応がほとんど進まないので好ましくない。したがって、中間減圧熱処理における水素圧力を水素吸収・分解処理時の水素圧力の２０〜６０％の圧力に定めた。
【００１４】
この中間減圧熱処理を施した後、さらに必要に応じて減圧水素中熱処理を施す。この減圧水素中熱処理は、水素吸収・分解処理した希土類磁石合金原料を水素圧力：０．６５〜１３ｋＰａであって中間減圧熱処理の水素圧力よりも低い圧力の水素雰囲気中に保持する処理である。この減圧水素中熱処理を施すことにより保磁力および残留磁束密度を一層向上させることができる。
【００１５】
この中間減圧熱処理を施しさらに必要に応じて減圧水素中熱処理を施したのち脱水素処理を行う。脱水素処理は到達圧：０．１３ｋＰａ以下の真空雰囲気に保持することにより希土類磁石合金原料から強制的に水素を十分放出させ、それにより一層の相変態を促す処理である。０．１３ｋＰａを越える到達圧では十分に脱水素が行われないからである。
この脱水素処理後に行なう冷却は不活性ガス（Ａｒガス）を流すことにより室温まで冷却する。冷却した後は粉砕して希土類磁石粉末とする。この粉砕して得られた希土類磁石粉末は必要に応じて熱処理することにより残留内部応力を除去する。
【００１６】
【発明の実施の形態】
高周波真空溶解炉を用いて溶解し、得られた溶湯を鋳造して表１に示される成分組成の希土類磁石合金原料の鋳塊ａ〜ｏを製造した。これら鋳塊ａ〜ｏを不活性ガス雰囲気中で粉砕して１０ｍｍ以下のブロックを作製した。
【００１７】
【表１】
実施例１
表１の鋳塊ａ〜ｅのブロックに表２に示される条件の水素吸収処理を施した後、この水素吸収処理したブロックを表２に示される条件で水素吸収・分解処理を施し、引き続いて表３に示される条件で中間減圧熱処理を行い、さらに表３に示される条件で減圧水素中熱処理を行ない、さらに表３に示される条件で脱水素処理を行った後、Ａｒガスで強制的に室温まで冷却し、３００μｍ以下に粉砕して希土類磁石粉末を製造することにより本発明法１〜５を実施した。
【００１９】
従来例１
表１の鋳塊ａ〜ｅのブロックを表２に示される条件の水素吸収処理を施した後、実施例と同じ条件で水素吸収・分解処理を施し、引き続いてＡｒガス雰囲気で中間熱処理を行い、さらに表３に示される条件で減圧水素中熱処理を行い、さらに表３に示される条件で脱水素処理を行った後、Ａｒガスで強制的に室温まで冷却し、３００μｍ以下に粉砕して希土類磁石粉末を製造することにより従来法１〜５を実施した。
【００２０】
本発明法１〜５および従来法１〜５により得られた希土類磁石粉末にそれぞれ３質量％のエポキシ樹脂を加えて混練し、１．６ＭＡ／ｍの磁場中で圧縮成形して圧粉体を作製し、この圧粉体をオーブンで１５０℃、２時間熱硬化して、密度：６．０〜６．１ｇ／ｃｍ３のボンド磁石を作製し、得られたボンド磁石の磁気特性を表３に示した。
【００２１】
さらに、本発明法１〜５および従来法１〜５により得られた希土類磁石粉末を磁場中で圧縮成形して異方性圧粉体を作製し、この異方性圧粉体をホットプレス装置にセットし、磁場の印加方向が圧縮方向になるようにＡｒガス中、温度：７５０℃、圧力：５８．８ＭＰａ 、１分間保持の条件でホットプレスを行い、急冷して密度：７．５〜７．７ｇ／ｃｍ３ のホットプレス磁石を作製し、得られたホットプレス磁石の磁気特性を表３に示した。
【００２２】
【表２】
【表３】
表１〜表３に示される結果から、水素吸収処理を施し、水素吸収・分解処理を施し、さらに中間減圧熱処理する本発明法１〜５により得られた希土類磁石粉末で作製したボンド磁石およびホットプレス磁石の磁気特性は、水素吸収処理を施し、水素吸収・分解処理を施したのち不活性ガス雰囲気中で中間熱処理する従来法１〜５により得られた希土類磁石粉末で作製したボンド磁石およびホットプレス磁石の磁気特性に比べて、残留磁束密度が向上していることが分かる。
【００２５】
実施例２
表１の鋳塊ｆ〜ｊのブロックに表４に示される条件の水素吸収処理を施した後、この水素吸収処理したブロックを表４に示される条件で水素吸収・分解処理を施し、引き続いて表４に示される条件で中間減圧熱処理を行い、さらに表５に示される条件で減圧水素中熱処理を行い、さらに表５に示される条件で脱水素処理を行った後、Ａｒガスで強制的に室温まで冷却し、３００μｍ以下に粉砕して希土類磁石粉末を製造することにより本発明法６〜１０を実施した。
【００２６】
従来例２
表１の鋳塊ｆ〜ｊのブロックを表４に示される実施例２と同じ条件の水素吸収処理を施した後、実施例２と同じ条件で水素吸収・分解処理を施し、引き続いて表４に示される条件でＡｒガス雰囲気の中間熱処理を行い、さらに表５に示される条件で減圧水素中熱処理を行い、さらに表５に示される条件で脱水素処理を行った後、Ａｒガスで強制的に室温まで冷却し、３００μｍ以下に粉砕して希土類磁石粉末を製造することにより従来法６〜１０を実施した。
【００２７】
本発明法６〜１０および従来法６〜１０により得られた希土類磁石粉末にそれぞれ３質量％のエポキシ樹脂を加えて混練し、１．６ＭＡ／ｍの磁場中で圧縮成形して圧粉体を作製し、この圧粉体をオーブンで１５０℃、２時間熱硬化して、密度：６．０〜６．１ｇ／ｃｍ３のボンド磁石を作製し、得られたボンド磁石の磁気特性を表５に示した。
【００２８】
さらに、本発明法６〜１０および従来法６〜１０により得られた希土類磁石粉末を磁場中で圧縮成形して異方性圧粉体を作製し、この異方性圧粉体をホットプレス装置にセットし、磁場の印加方向が圧縮方向になるようにＡｒガス中、温度：７５０℃、圧力：５８．８ＭＰａ 、１分間保持の条件でホットプレスを行い、急冷して密度：７．５〜７．７ｇ／ｃｍ３ のホットプレス磁石を作製し、得られたホットプレス磁石の磁気特性を表５に示した。
【００２９】
【表４】
【表５】
表１、表４および表５に示される結果から、水素吸収処理を施し、水素吸収・分解処理を施したのち中間減圧熱処理する本発明法６〜１０により得られた希土類磁石粉末で作製したボンド磁石およびホットプレス磁石の磁気特性は、水素吸収処理を施し、水素吸収・分解処理を施したのちＡｒガス雰囲気中で中間熱処理する従来法６〜１０により得られた希土類磁石粉末で作製したボンド磁石およびホットプレス磁石の磁気特性に比べて、特に残留磁束密度が向上していることが分かる。
【００３２】
実施例３
表１の鋳塊ｋ〜ｏのブロックに表６に示される条件の水素吸収処理を施した後、この水素吸収処理したブロックを表６に示される条件で水素吸収・分解処理を施し、引き続いて表６に示される条件で中間減圧熱処理を行い、さらに表７に示される条件で減圧水素中熱処理を行い、さらに表７に示される条件で脱水素処理を行った後、Ａｒガスで強制的に室温まで冷却し、３００μｍ以下に粉砕して希土類磁石粉末を製造することにより本発明法１１〜１５を実施した。
【００３３】
従来例３
表１の鋳塊ｋ〜ｏのブロックを表６に示される実施例３と同じ条件の水素吸収処理を施した後、実施例３と同じ条件で水素吸収・分解処理を施し、引き続いて表６に示される条件でＡｒガス雰囲気の中間熱処理を行い、さらに表７に示される条件で減圧水素中熱処理を行い、さらに表７に示される条件で脱水素処理を行った後、Ａｒガスで強制的に室温まで冷却し、３００μｍ以下に粉砕して希土類磁石粉末を製造することにより従来法１１〜１５を実施した。
【００３４】
本発明法１１〜１５および従来法１１〜１５により得られた希土類磁石粉末にそれぞれ３質量％のエポキシ樹脂を加えて混練し、１．６ＭＡ／ｍの磁場中で圧縮成形して圧粉体を作製し、この圧粉体をオーブンで１５０℃、２時間熱硬化して、密度：６．０〜６．１ｇ／ｃｍ３のボンド磁石を作製し、得られたボンド磁石の磁気特性を表７に示した。
【００３５】
さらに、本発明法１１〜１５および従来法１１〜１５により得られた希土類磁石粉末を磁場中で圧縮成形して異方性圧粉体を作製し、この異方性圧粉体をホットプレス装置にセットし、磁場の印加方向が圧縮方向になるようにＡｒガス中、温度：７５０℃、圧力：５８．８ＭＰａ 、１分間保持の条件でホットプレスを行い、急冷して密度：７．５〜７．７ｇ／ｃｍ３ のホットプレス磁石を作製し、得られたホットプレス磁石の磁気特性を表７に示した。
【００３６】
【表６】
【表７】
表１、表６および表７に示される結果から、水素吸収処理を施し、水素吸収・分解処理を施したのち中間減圧熱処理する本発明法１１〜１５により得られた希土類磁石粉末で作製したボンド磁石およびホットプレス磁石の磁気特性は、水素吸収処理を施し、水素吸収・分解処理を施したのちＡｒガス雰囲気中で中間熱処理する従来法１１〜１５により得られた希土類磁石粉末で作製したボンド磁石およびホットプレス磁石の磁気特性に比べて、特に残留磁束密度が向上していることが分かる。
【００３９】
【発明の効果】
（ｉ）希土類磁石合金原料を水素吸収処理→水素吸収・分解処理→中間減圧熱処理→必要に応じて減圧水素中熱処理→脱水素処理の順序で施すこの発明の希土類磁石粉末の製造方法により作製した希土類磁石粉末は、水素吸収処理→水素吸収・分解処理→中間熱処理→必要に応じて減圧水素中熱処理→脱水素処理の順序で施す従来の希土類磁石粉末の製造方法により作製した希土類磁石粉末に比べて磁気異方性に優れている、
（ｉｉ）この発明の希土類磁石粉末の製造方法は、不活性ガスの導入は最後の冷却工程だけであって、その他の工程では水素ガスの導入および排出の圧力条件だけで制御することができるので製造コストを大幅に削減することができ、一層優れた希土類磁石粉末を安価に提供することができる、
など産業上優れた効果を奏するものである。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for producing a rare earth magnet powder having excellent magnetic anisotropy, particularly a method for producing a rare earth magnet powder having further excellent residual magnetic flux density.
[0002]
[Prior art]
R (where R represents a rare earth element containing Y; the same applies hereinafter), M (where M is Ga, Zr, Nb, Mo, Hf, Ta, W, Ni, Al, Ti, V, Cu, Cr, If one or more of Ge, C and Si are shown, the same shall apply hereinafter), in terms of atomic% (hereinafter,% indicates atomic%), R: 10 to 20%, Co: 0 to 50% , B: 3 to 20%, M: 0 to 5%, the balance being a rare earth magnet alloy raw material having a component composition of Fe and unavoidable impurities in an Ar gas atmosphere at a temperature of 600 to 1200 ° C. After homogenization treatment or without homogenization treatment, the temperature is increased from room temperature to a predetermined temperature of less than 500 ° C. in a hydrogen atmosphere, or after the temperature is raised and held, and subjected to hydrogen absorption treatment,
Hydrogen pressure: In a hydrogen atmosphere of 10 to 1000 kPa, the temperature is raised and maintained at a predetermined temperature in the range of 500 to 1000 ° C. so that the rare earth magnet alloy raw material absorbs hydrogen to promote decomposition by phase transformation. Subject to disassembly,
Subsequently, the rare earth magnet alloy raw material subjected to the hydrogen absorption / decomposition treatment is maintained in an inert gas atmosphere at a predetermined temperature in the range of inert gas pressure: 10 to 1000 kPa and temperature: 500 to 1000 ° C. Heat treatment,
Subsequently, if necessary, the rare-earth magnet alloy raw material that has been subjected to the intermediate heat treatment is treated at a predetermined temperature in the range of 500 to 1000 ° C. in a hydrogen atmosphere having an absolute pressure of less than 0.65 to 10 kPa or a hydrogen partial pressure: : Heat treatment in reduced pressure hydrogen while keeping a part of hydrogen in the rare earth magnet alloy raw material by maintaining in a mixed gas atmosphere of hydrogen and inert gas of less than 0.65 to 10 kPa,
Thereafter, a dehydrogenation treatment is performed at a predetermined temperature in the range of 500 ° C. to 1000 ° C. to release hydrogen by forcibly releasing hydrogen by maintaining a vacuum atmosphere with an ultimate pressure of 0.13 kPa or less to promote phase transformation, and then cooling. A method for producing a rare earth magnet powder having excellent magnetic anisotropy, which comprises a pulverizing step, is known (see JP-A-2000-21614).
[0003]
[Problems to be solved by the invention]
In recent years, the electric and electronic industries have been demanding rare earth magnet powders that are more excellent in magnetic anisotropy and more inexpensive. A method for efficiently and inexpensively producing rare earth magnet powders that are more excellent in magnetic anisotropy and less expensive. Has been researched and developed.
[0004]
[Means for Solving the Problems]
Therefore, the present inventors have also studied to develop a method for efficiently producing a rare-earth magnet powder having more excellent magnetic anisotropy at low cost. as a result,
(A) An inert gas is supplied after the hydrogen absorption / decomposition treatment in the above-mentioned conventional method for producing a rare earth magnet powder having excellent magnetic anisotropy, and the inert gas pressure is in the range of 10 to 1000 kPa and the temperature is in the range of 500 to 1000 ° C. Instead of the intermediate heat treatment in an inert gas atmosphere at a predetermined temperature in the above, while maintaining the temperature in the range of 500 to 1000 ° C., the hydrogen pressure is increased to 20 to 60 of the hydrogen pressure in the hydrogen absorption / decomposition treatment. %, And the residual magnetic flux density is improved by performing the intermediate pressure-reduction heat treatment in a hydrogen atmosphere at a pressure of 1.5% compared with the conventional intermediate heat treatment in an inert gas atmosphere after the hydrogen absorption / decomposition treatment.
(B) This intermediate pressure reduction heat treatment is the same hydrogen atmosphere as the hydrogen absorption / decomposition treatment, and simply reduces the pressure by evacuating hydrogen. Therefore, the operation is simpler than the conventional intermediate heat treatment introducing an inert gas. This is a method suitable for mass production, and furthermore, a research result has been obtained that the magnetic anisotropy, particularly the residual magnetic flux density, is further improved as compared with the rare earth magnet powder manufactured by the conventional manufacturing method.
[0005]
The present invention has been made based on such research results,
(1) A rare earth magnet alloy raw material homogenized at a temperature of 600 to 1200 ° C. in a vacuum or Ar gas atmosphere, if necessary, is heated from room temperature to a temperature of from 10 to 1000 kPa in a hydrogen gas atmosphere. Performing a hydrogen absorption treatment of absorbing hydrogen by raising the temperature to a temperature of less than 500 ° C. or raising and holding the temperature,
The rare earth magnet alloy raw material subjected to the hydrogen absorption treatment is heated to a temperature in the range of 500 to 1000 ° C. in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa and held there, so that the rare earth magnet alloy raw material can further absorb hydrogen. Hydrogen absorption and decomposition treatment
Subsequently, the rare-earth magnet alloy raw material subjected to the hydrogen absorption / decomposition treatment is kept at a temperature in the range of 500 to 1000 ° C. in a hydrogen atmosphere at a pressure of 20 to 60% of the hydrogen pressure at the time of the hydrogen absorption / decomposition treatment. Intermediate vacuum heat treatment,
After that, a dehydrogenation treatment for forcibly releasing hydrogen from the rare-earth magnet alloy raw material by maintaining a vacuum atmosphere with an ultimate pressure of 0.13 kPa or less at a temperature within the range of 500 to 1000 ° C. to promote phase transformation is performed. Then, a method of manufacturing a rare earth magnet powder excellent in magnetic anisotropy to be cooled and pulverized,
(2) The rare earth magnet alloy raw material homogenized in a vacuum or Ar gas atmosphere at a temperature of 600 to 1200 ° C. as necessary in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa from room temperature to 500: Performing a hydrogen absorption treatment to absorb hydrogen by raising the temperature to a temperature of less than ℃, or raising and maintaining the temperature,
The rare earth magnet alloy raw material subjected to the hydrogen absorption treatment is heated to a temperature in the range of 500 to 1000 ° C. in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa and held there, so that the rare earth magnet alloy raw material can further absorb hydrogen. Hydrogen absorption and decomposition treatment
Subsequently, intermediate pressure reduction is performed in which the rare earth magnet alloy raw material subjected to the hydrogen absorption / decomposition treatment is held at a temperature within the range of 500 to 1000 ° C. in a hydrogen atmosphere at a pressure of 20 to 60% of the pressure at the time of the hydrogen absorption / decomposition treatment. Heat treatment,
Subsequently, hydrogen is partially left in the rare-earth magnet alloy raw material by maintaining the same in a hydrogen atmosphere at a temperature in the range of 500 to 1000 ° C. and a pressure of 0.65 to 13 kPa and a pressure lower than the pressure of the intermediate pressure reduction heat treatment. Heat treatment in reduced pressure hydrogen
After that, a dehydrogenation treatment for forcibly releasing hydrogen from the rare-earth magnet alloy raw material by maintaining a vacuum atmosphere with an ultimate pressure of 0.13 kPa or less at a temperature within the range of 500 to 1000 ° C. to promote phase transformation is performed. Then, it is cooled and pulverized, and is characterized by a method for producing a rare earth magnet powder having excellent magnetic anisotropy.
[0006]
The rare earth magnet alloy raw material used in the present invention is:
R: 10 to 20%, B: 3 to 20%, the remainder is a rare earth magnet alloy raw material having a component composition of Fe and unavoidable impurities,
A rare earth magnet alloy raw material containing R: 10 to 20%, B: 3 to 20%, M: 0.001 to 5%, and a balance of Fe and unavoidable impurities;
Rare earth magnet alloy raw material containing R: 10 to 20%, Co: 0.1 to 50%, B: 3 to 20%, and having a balance of Fe and unavoidable impurities, or R: 10 to 20 %, Co: 0.1 to 50%, B: 3 to 20%, M: 0.001 to 5%, and a rare earth magnet alloy raw material having a component composition of the balance of Fe and inevitable impurities is preferable.
[0007]
Next, the reason why the composition of the rare earth magnet alloy raw material used in the present invention and the production conditions are limited as described above will be described.
(A) Component composition R (rare earth element including Y):
R is a rare earth element mainly composed of Nd and a trace amount of Y, Dy, Pr, Sm, Ce, La, Tb, Er, Eu, Gd, Tm, Yb, Lu, Ho, etc. If it is less than 10%, the coercive force will be reduced, while if it exceeds 20%, the saturation magnetization will be reduced and the desired magnetic properties will not be obtained, which is not preferable. Therefore, the content of R is set to 10 to 20%.
[0008]
B:
If the content of B is less than 3%, the coercive force decreases, while if it exceeds 20%, the saturation magnetization decreases, and any desired magnetic properties cannot be obtained. Therefore, the content of B is set to 3 to 20%.
[0009]
Co:
Co is added as necessary to prevent the rare earth magnet alloy from becoming isotropic. If the content is less than 0.1%, the desired effect cannot be obtained. In addition, since the coercive force and the saturation magnetization decrease, high characteristics cannot be obtained even if the anisotropy is obtained. Therefore, the content of Co contained in the rare earth magnet alloy raw material used in the method for producing a rare earth magnet powder of the present invention is set to 0.1 to 50% (more preferably, 5 to 30%).
[0010]
M (one or more of Ga, Zr, Nb, Mo, Hf, Ta, W, Ni, Al, Ti, V, Cu, Cr, Ge, C and Si):
M is added as necessary to further improve the coercive force and the residual magnetic flux density. If the content is less than 0.001%, the desired effect cannot be obtained. Then, the coercive force and the residual magnetic flux density decrease, which is not preferable. Therefore, the content of M is set to 0.001 to 5%.
[0011]
(B) Manufacturing Conditions The rare earth magnet alloy raw material is heated in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa to a predetermined temperature from room temperature to a predetermined temperature of less than 500 ° C., or heated to a predetermined temperature of less than 500 ° C. ( For example, a hydrogen absorption process of absorbing hydrogen by maintaining the temperature at 100 ° C.) is performed. This rare earth magnet alloy raw material is heated in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa to a predetermined temperature from room temperature to a temperature of less than 500 ° C., or a hydrogen absorption process of raising the temperature is a conventionally performed process. is there.
[0012]
The hydrogen-absorbed rare earth magnet alloy raw material is further heated and subjected to a hydrogen absorption / decomposition treatment in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa and a temperature of 500 to 1000 ° C. and a predetermined temperature within a range of 500 to 1000 ° C. The raw material absorbs hydrogen to promote phase transformation and decompose. The condition for maintaining the temperature in the hydrogen gas atmosphere of 10 to 1000 kPa in the hydrogen absorption / decomposition step at a predetermined temperature in the range of 500 to 1000 ° C. is a known condition, and particularly a novel condition. Therefore, the explanation of the reason for the limitation is omitted.
[0013]
After the hydrogen absorption / decomposition treatment, at a temperature within the range of 500 to 1000 ° C., a pressure of 20 to 60% of the hydrogen pressure at the time of the hydrogen absorption / decomposition treatment (specifically, the pressure: 2 to 600 kPa and hydrogen An intermediate pressure reduction heat treatment is performed in a hydrogen atmosphere at a pressure (relatively lower than the hydrogen pressure during the absorption / decomposition treatment). This intermediate pressure-reduction heat treatment is a treatment step that replaces the conventional intermediate heat treatment performed in an inert gas atmosphere. After the hydrogen absorption / decomposition treatment, the hydrogen gas is exhausted while maintaining the temperature at 500 to 1000 ° C., and the pressure is reduced by reducing the pressure. Hydrogen pressure, it is not necessary to replace the atmosphere with an inert gas atmosphere, the intermediate pressure reduction heat treatment can be performed by a simple operation, and the effect of further increasing the residual magnetic flux density can be obtained.
The reason why the hydrogen pressure in the intermediate pressure reduction heat treatment is set to 20 to 60% of the hydrogen pressure during the hydrogen absorption / decomposition treatment is that if the pressure is maintained at less than 20% of the hydrogen pressure during the hydrogen absorption / decomposition treatment, When the hydrogen pressure is kept higher than 60% of the hydrogen pressure at the time of hydrogen absorption / decomposition treatment, the reaction of anisotropy hardly occurs. It is not preferable because it does not proceed. Therefore, the hydrogen pressure in the intermediate pressure reduction heat treatment was set to 20 to 60% of the hydrogen pressure in the hydrogen absorption / decomposition treatment.
[0014]
After performing the intermediate reduced pressure heat treatment, a heat treatment in reduced pressure hydrogen is further performed as necessary. This heat treatment in reduced pressure hydrogen is a process of maintaining the rare earth magnet alloy raw material subjected to the hydrogen absorption / decomposition treatment in a hydrogen atmosphere having a hydrogen pressure of 0.65 to 13 kPa and lower than the hydrogen pressure in the intermediate reduced pressure heat treatment. By performing the heat treatment in reduced pressure hydrogen, the coercive force and the residual magnetic flux density can be further improved.
[0015]
This intermediate reduced pressure heat treatment is performed, and if necessary, a heat treatment in reduced pressure hydrogen is performed, followed by dehydrogenation treatment. The dehydrogenation treatment is a treatment for forcibly releasing sufficient hydrogen from the rare earth magnet alloy raw material by maintaining a vacuum atmosphere with an ultimate pressure of 0.13 kPa or less, thereby promoting further phase transformation. If the ultimate pressure exceeds 0.13 kPa, dehydrogenation is not sufficiently performed.
Cooling performed after this dehydrogenation treatment is performed by flowing an inert gas (Ar gas) to cool to room temperature. After cooling, it is pulverized into rare earth magnet powder. The rare-earth magnet powder obtained by this pulverization is subjected to a heat treatment as necessary to remove residual internal stress.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Melting was performed using a high-frequency vacuum melting furnace, and the obtained molten metal was cast to produce ingots a to o of rare earth magnet alloy raw materials having the component compositions shown in Table 1. These ingots a to o were pulverized in an inert gas atmosphere to produce blocks of 10 mm or less.
[0017]
[Table 1]
Example 1
After subjecting the blocks of ingots a to e in Table 1 to the hydrogen absorption treatment under the conditions shown in Table 2, the blocks subjected to the hydrogen absorption treatment are subjected to the hydrogen absorption / decomposition treatment under the conditions shown in Table 2, and subsequently, Intermediate reduced pressure heat treatment was performed under the conditions shown in Table 3, further heat treatment in reduced pressure hydrogen was performed under the conditions shown in Table 3, and dehydrogenation was further performed under the conditions shown in Table 3. The methods 1 to 5 of the present invention were carried out by cooling to room temperature and pulverizing the powder to 300 μm or less to produce a rare earth magnet powder.
[0019]
Conventional example 1
After subjecting the blocks of ingots a to e in Table 1 to a hydrogen absorption treatment under the conditions shown in Table 2, the blocks were subjected to a hydrogen absorption / decomposition treatment under the same conditions as in the example, and then an intermediate heat treatment was performed in an Ar gas atmosphere. Further, a heat treatment in reduced pressure hydrogen is performed under the conditions shown in Table 3, and a dehydrogenation treatment is further performed under the conditions shown in Table 3. Then, the mixture is forcibly cooled to room temperature with Ar gas, and pulverized to 300 μm or less. Conventional methods 1 to 5 were carried out by producing magnet powder.
[0020]
Each of the rare earth magnet powders obtained by the methods 1 to 5 of the present invention and the conventional methods 1 to 5 is mixed with 3% by mass of an epoxy resin, kneaded, and compression-molded in a magnetic field of 1.6 MA / m to obtain a green compact. The compact was thermally cured in an oven at 150 ° C. for 2 hours to produce a bonded magnet having a density of 6.0 to 6.1 g / cm 3. Table 3 shows the magnetic properties of the obtained bonded magnet. It was shown to.
[0021]
Further, the rare earth magnet powders obtained by the methods 1 to 5 of the present invention and the conventional methods 1 to 5 are compression-molded in a magnetic field to produce an anisotropic green compact, and this anisotropic green compact is hot-pressed. In Ar gas at a temperature of 750 ° C. and a pressure of 58.8 MPa so that the direction of application of the magnetic field is in the compression direction. Hot pressing was performed for 1 minute, and quenched to produce a hot pressed magnet having a density of 7.5 to 7.7 g / cm 3. The magnetic properties of the obtained hot pressed magnet are shown in Table 3. .
[0022]
[Table 2]
[Table 3]
From the results shown in Tables 1 to 3, a bonded magnet and a hot magnet made of the rare earth magnet powder obtained by the present invention methods 1 to 5, which are subjected to a hydrogen absorption treatment, a hydrogen absorption / decomposition treatment, and an intermediate reduced pressure heat treatment. The magnetic properties of the pressed magnets are as follows: the bonded magnets made of the rare earth magnet powders obtained by the conventional methods 1 to 5 are subjected to a hydrogen absorption treatment, subjected to a hydrogen absorption / decomposition treatment, and then subjected to an intermediate heat treatment in an inert gas atmosphere. It can be seen that the residual magnetic flux density is improved as compared with the magnetic properties of the press magnet.
[0025]
Example 2
After subjecting the blocks of ingots f to j in Table 1 to the hydrogen absorption treatment under the conditions shown in Table 4, the blocks subjected to the hydrogen absorption treatment are subjected to the hydrogen absorption / decomposition treatment under the conditions shown in Table 4, and subsequently, Intermediate reduced pressure heat treatment was performed under the conditions shown in Table 4, further heat treatment in reduced pressure hydrogen was performed under the conditions shown in Table 5, and dehydrogenation was further performed under the conditions shown in Table 5. Methods 6 to 10 of the present invention were carried out by cooling to room temperature and pulverizing the particles to 300 μm or less to produce rare earth magnet powder.
[0026]
Conventional example 2
After subjecting the blocks of ingots f to j in Table 1 to the hydrogen absorption treatment under the same conditions as in Example 2 shown in Table 4, the blocks were subjected to the hydrogen absorption / decomposition treatment under the same conditions as in Example 2. After performing an intermediate heat treatment in an Ar gas atmosphere under the conditions shown in Table 5, further performing a heat treatment in reduced pressure hydrogen under the conditions shown in Table 5, and further performing a dehydrogenation treatment under the conditions shown in Table 5, Conventional methods 6 to 10 were carried out by cooling to room temperature and pulverizing the particles to 300 μm or less to produce rare earth magnet powder.
[0027]
Each of the rare earth magnet powders obtained by the methods 6 to 10 of the present invention and the conventional methods 6 to 10 is kneaded by adding 3% by mass of an epoxy resin, and compression-molded in a magnetic field of 1.6 MA / m to obtain a green compact. The compact was thermally cured in an oven at 150 ° C. for 2 hours to produce a bonded magnet having a density of 6.0 to 6.1 g / cm 3. The magnetic properties of the obtained bonded magnet are shown in Table 5. It was shown to.
[0028]
Further, the rare earth magnet powders obtained by the methods 6 to 10 of the present invention and the conventional methods 6 to 10 are compression-molded in a magnetic field to produce an anisotropic green compact, and the anisotropic green compact is hot-pressed. In Ar gas at a temperature of 750 ° C. and a pressure of 58.8 MPa so that the direction of application of the magnetic field is in the compression direction. Hot pressing was performed for 1 minute, and quenched to produce a hot pressed magnet having a density of 7.5 to 7.7 g / cm 3. Table 5 shows the magnetic properties of the obtained hot pressed magnet. .
[0029]
[Table 4]
[Table 5]
From the results shown in Table 1, Table 4 and Table 5, the bond produced from the rare earth magnet powder obtained by the present invention methods 6 to 10 in which the hydrogen absorption treatment is performed, the hydrogen absorption / decomposition treatment is performed, and then the intermediate pressure reduction heat treatment is performed. The magnetic properties of the magnet and the hot-pressed magnet are as follows: a bonded magnet made of a rare-earth magnet powder obtained by a conventional method 6 to 10 in which hydrogen absorption treatment is performed, hydrogen absorption / decomposition treatment is performed, and then intermediate heat treatment is performed in an Ar gas atmosphere. It can be seen that the residual magnetic flux density is particularly improved as compared with the magnetic properties of the hot-pressed magnet.
[0032]
Example 3
After subjecting the blocks of ingots k to o in Table 1 to a hydrogen absorption treatment under the conditions shown in Table 6, the blocks subjected to the hydrogen absorption treatment were subjected to a hydrogen absorption / decomposition treatment under the conditions shown in Table 6, and subsequently, Intermediate reduced pressure heat treatment was performed under the conditions shown in Table 6, further heat treatment in reduced pressure hydrogen was performed under the conditions shown in Table 7, and dehydrogenation was further performed under the conditions shown in Table 7. The methods 11 to 15 of the present invention were carried out by cooling to room temperature and pulverizing the particles to 300 μm or less to produce rare earth magnet powder.
[0033]
Conventional example 3
After subjecting the blocks of ingots k to o in Table 1 to the hydrogen absorption treatment under the same conditions as in Example 3 shown in Table 6, the blocks were subjected to the hydrogen absorption / decomposition treatment under the same conditions as in Example 3. After performing an intermediate heat treatment in an Ar gas atmosphere under the conditions shown in Table 7, further performing a heat treatment in reduced pressure hydrogen under the conditions shown in Table 7, and further performing a dehydrogenation treatment under the conditions shown in Table 7, Conventional methods 11 to 15 were carried out by cooling to room temperature and pulverizing to 300 μm or less to produce rare earth magnet powder.
[0034]
Each of the rare earth magnet powders obtained by the methods 11 to 15 of the present invention and the conventional methods 11 to 15 is mixed with 3% by mass of an epoxy resin, kneaded, and compression-molded in a magnetic field of 1.6 MA / m to form a green compact. The compact was thermally cured in an oven at 150 ° C. for 2 hours to produce a bonded magnet having a density of 6.0 to 6.1 g / cm 3. Table 7 shows the magnetic properties of the obtained bonded magnet. It was shown to.
[0035]
Further, the rare earth magnet powders obtained by the methods 11 to 15 of the present invention and the conventional methods 11 to 15 are compression-molded in a magnetic field to produce an anisotropic green compact. In Ar gas at a temperature of 750 ° C. and a pressure of 58.8 MPa so that the direction of application of the magnetic field is in the compression direction. Hot pressing was performed for 1 minute, and quenched to produce a hot pressed magnet having a density of 7.5 to 7.7 g / cm 3. Table 7 shows the magnetic properties of the obtained hot pressed magnet. .
[0036]
[Table 6]
[Table 7]
From the results shown in Table 1, Table 6 and Table 7, the bond produced from the rare earth magnet powder obtained by the present invention methods 11 to 15 in which the hydrogen absorption treatment is performed, the hydrogen absorption / decomposition treatment is performed, and then the intermediate pressure reduction heat treatment is performed. The magnetic properties of the magnet and the hot-pressed magnet are as follows: a bonded magnet made of a rare-earth magnet powder obtained by conventional methods 11 to 15 in which a hydrogen absorption treatment is performed, a hydrogen absorption / decomposition treatment is performed, and then an intermediate heat treatment is performed in an Ar gas atmosphere. It can be seen that the residual magnetic flux density is particularly improved as compared with the magnetic properties of the hot-pressed magnet.
[0039]
【The invention's effect】
(I) The rare earth magnet alloy raw material is produced by the method for producing rare earth magnet powder of the present invention in which hydrogen absorbing treatment → hydrogen absorbing / decomposing treatment → intermediate reduced pressure heat treatment → heat treatment in reduced pressure hydrogen as needed → dehydrogenation treatment Rare-earth magnet powders are compared with rare-earth magnet powders produced by the conventional method of manufacturing rare-earth magnet powders, which are applied in the order of hydrogen absorption treatment → hydrogen absorption / decomposition treatment → intermediate heat treatment → heat treatment in reduced pressure hydrogen if necessary → dehydrogenation treatment. Excellent in magnetic anisotropy,
(Ii) In the method for producing a rare earth magnet powder according to the present invention, the introduction of the inert gas is performed only in the last cooling step, and the other steps can be controlled only by the pressure conditions of the introduction and discharge of the hydrogen gas. The manufacturing cost can be greatly reduced, and a more excellent rare earth magnet powder can be provided at low cost.
It has excellent industrial effects.
Claims (4)
この水素吸収処理した前記希土類磁石合金原料を圧力：１０〜１０００ｋＰａの水素ガス雰囲気中で５００〜１０００℃の範囲内の温度に昇温し保持することにより前記希土類磁石合金原料にさらに水素を吸収させて分解する水素吸収・分解処理を施し、
引き続いて、水素吸収・分解処理を施した希土類磁石合金原料を５００〜１０００℃の範囲内の温度に保持しながら水素吸収・分解処理時の水素ガス圧力の２０〜６０％の圧力の水素雰囲気中に保持する中間減圧熱処理を施し、
その後、５００〜１０００℃の範囲内の温度で到達圧：０．１３ｋＰａ以下の真空雰囲気に保持することにより希土類磁石合金原料から強制的に水素を放出させて相変態を促す脱水素処理を施し、ついで冷却し、粉砕することを特徴とする磁気異方性に優れた希土類磁石粉末の製造方法。The rare earth magnet alloy raw material is subjected to a hydrogen absorption process of absorbing hydrogen by raising or holding the temperature from room temperature to a temperature of less than 500 ° C. in a hydrogen gas atmosphere having a pressure of 10 to 1000 kPa.
The rare earth magnet alloy raw material subjected to the hydrogen absorption treatment is heated to a temperature in the range of 500 to 1000 ° C. in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa and held there, so that the rare earth magnet alloy raw material can further absorb hydrogen. Hydrogen absorption and decomposition treatment
Subsequently, while maintaining the rare earth magnet alloy raw material subjected to the hydrogen absorption / decomposition treatment at a temperature in the range of 500 to 1000 ° C., the hydrogen absorption / decomposition treatment is performed in a hydrogen atmosphere at a pressure of 20 to 60% of the hydrogen gas pressure at the time of the hydrogen absorption / decomposition treatment. Subjected to an intermediate vacuum heat treatment,
After that, a dehydrogenation treatment for forcibly releasing hydrogen from the rare-earth magnet alloy raw material by maintaining a vacuum atmosphere with an ultimate pressure of 0.13 kPa or less at a temperature within the range of 500 to 1000 ° C. to promote phase transformation is performed. A method for producing a rare earth magnet powder having excellent magnetic anisotropy, which is then cooled and pulverized.
この粉砕処理した前記希土類磁石合金原料を圧力：１０〜１０００ｋＰａの水素ガス雰囲気中で５００〜１０００℃の範囲内の温度に昇温し保持することにより前記希土類磁石合金原料にさらに水素を吸収させて分解する水素吸収・分解処理を施し、
引き続いて、水素吸収・分解処理を施した希土類磁石合金原料を５００〜１０００℃の範囲内の温度に保持しながら水素圧力を水素吸収・分解処理時の水素圧力の２０〜６０％の圧力の水素雰囲気中に保持する中間減圧熱処理を施し、
引き続いて、５００〜１０００℃の範囲内の温度で圧力：０．６５〜１３ｋＰａでかつ中間減圧熱処理の圧力よりも低い圧力の水素雰囲気中に保持することにより希土類磁石合金原料に水素を一部残したまま減圧水素中熱処理を行い、
その後、５００〜１０００℃の範囲内の温度で到達圧：０．１３ｋＰａ以下の真空雰囲気に保持することにより希土類磁石合金原料から強制的に水素を放出させて相変態を促す脱水素処理を施し、ついで冷却し、粉砕することを特徴とする磁気異方性に優れた希土類磁石粉末の製造方法。The rare earth magnet alloy raw material is subjected to a hydrogen absorption treatment in which hydrogen is absorbed by raising the temperature from room temperature to a predetermined temperature of less than 500 ° C. or a temperature of less than 500 ° C. in a hydrogen gas atmosphere having a pressure of 10 to 1000 kPa.
The pulverized rare-earth magnet alloy raw material is heated to a temperature in the range of 500 to 1000 ° C. in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa and held, whereby hydrogen is further absorbed by the rare-earth magnet alloy raw material. Decompose hydrogen absorption and decomposition treatment,
Subsequently, while maintaining the rare earth magnet alloy raw material subjected to the hydrogen absorption / decomposition treatment at a temperature within the range of 500 to 1000 ° C., the hydrogen pressure is increased to 20 to 60% of the hydrogen pressure at the time of the hydrogen absorption / decomposition treatment. Apply an intermediate vacuum heat treatment to keep it in the atmosphere,
Subsequently, hydrogen is partially left in the rare-earth magnet alloy raw material by maintaining the same in a hydrogen atmosphere at a temperature in the range of 500 to 1000 ° C. and a pressure of 0.65 to 13 kPa and a pressure lower than the pressure of the intermediate pressure reduction heat treatment. Heat treatment in reduced pressure hydrogen
After that, a dehydrogenation treatment for forcibly releasing hydrogen from the rare-earth magnet alloy raw material by maintaining a vacuum atmosphere with an ultimate pressure of 0.13 kPa or less at a temperature within the range of 500 to 1000 ° C. to promote phase transformation is performed. A method for producing a rare earth magnet powder having excellent magnetic anisotropy, which is then cooled and pulverized.
Ｒ（但し、ＲはＹを含む希土類元素を示す。以下同じ）：１０〜２０％、Ｂ：３〜２０％を含有し、残部がＦｅおよび不可避不純物からなる成分組成を有する希土類磁石合金原料、
Ｒ：１０〜２０％、Ｂ：３〜２０％、Ｍ（但し、ＭはＧａ、Ｚｒ、Ｎｂ、Ｍｏ、Ｈｆ、Ｔａ、Ｗ、Ｎｉ、Ａｌ、Ｔｉ、Ｖ、Ｃｕ、Ｃｒ、Ｇｅ、ＣおよびＳｉの内の１種または２種以上を示す。以下同じ）：０．００１〜５％を含有し、残部がＦｅおよび不可避不純物からなる成分組成を有する希土類磁石合金原料、
Ｒ：１０〜２０％、Ｃｏ：０．１〜５０％、Ｂ：３〜２０％を含有し、残部がＦｅおよび不可避不純物からなる成分組成を有する希土類磁石合金原料、または、Ｒ：１０〜２０％、Ｃｏ：０．１〜５０％、Ｂ：３〜２０％、Ｍ：０．００１〜５％を含有し、残部がＦｅおよび不可避不純物からなる成分組成を有する希土類磁石合金原料であることを特徴とする磁気異方性に優れた希土類磁石粉末の製造方法。The rare earth magnet alloy raw material according to claim 1 or 2 is expressed in atomic% (hereinafter,% indicates atomic%),
R (where R represents a rare earth element containing Y; the same applies hereinafter): 10 to 20%, B: 3 to 20%, rare earth magnet alloy raw material having a component composition of Fe and unavoidable impurities,
R: 10 to 20%, B: 3 to 20%, M (where M is Ga, Zr, Nb, Mo, Hf, Ta, W, Ni, Al, Ti, V, Cu, Cr, Ge, C and One or more of Si, the same shall apply hereinafter): a rare earth magnet alloy raw material containing 0.001 to 5% and having a balance of Fe and inevitable impurities.
Rare earth magnet alloy raw material containing R: 10 to 20%, Co: 0.1 to 50%, B: 3 to 20%, and having a balance of Fe and unavoidable impurities, or R: 10 to 20 %, Co: 0.1 to 50%, B: 3 to 20%, M: 0.001 to 5%, the balance being a rare earth magnet alloy raw material having a component composition of Fe and unavoidable impurities. A method for producing a rare earth magnet powder having excellent magnetic anisotropy.
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