JP2004218042A - Method for producing rare earth magnet powder excellent in magnetic anisotropy and heat stability - Google Patents
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Abstract
Description
【０００１】
【発明の属する技術分野】
この発明は、磁気異方性および熱的安定性に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、必要に応じて、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・電子業界では一層磁気異方性に優れた希土類磁石粉末が求められており、特に保磁力および残留磁束密度が共に一層優れた磁気異方性および熱的安定性を有する希土類磁石粉末が求められている。
【０００４】
【課題を解決するための手段】
そこで、本発明者らは、一層優れた磁気異方性および熱的安定性を有する希土類磁石粉末の製造方法を開発すべく研究を行った結果、
（イ）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いて、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、または昇温し保持して水素吸収処理した希土類磁石合金原料を平均粒径：１０〜５００μｍになるまで粉砕処理して水素吸収処理した希土類磁石合金原料粉末を作製し、この水素吸収処理した希土類磁石合金原料粉末を水素圧力：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、その後、従来と同様に引き続いて、必要に応じて、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、粉砕すると、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が一層向上する、
（ロ）また、この磁気異方性に優れた希土類磁石粉末の製造方法によると、水素粉砕後、ＨＤＤＲ処理を施すと、磁石粉末の表面凹凸が減少して平滑な表面になり、比表面積が減少するために熱的安定性が向上する、
（ハ）前記希土類磁石合金原料は、原子％で（以下、％は原子％を示す）、
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であることが好ましい、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前記成分組成を有する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希土類磁石合金原料を平均粒径：１０〜５００μｍになるまで粉砕処理して水素吸収処理した希土類磁石合金原料粉末を作製し、
この粉砕処理した前記希土類磁石合金原料粉末を圧力：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粉末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、
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、解砕する磁気異方性および熱的安定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前記成分組成を有する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希土類磁石合金原料を平均粒径：１０〜５００μｍになるまで粉砕処理して水素吸収処理した希土類磁石合金原料粉末を作製し、
この粉砕処理した前記希土類磁石合金原料粉末を圧力：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粉末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℃の範囲内の温度で圧力：１０〜１０００ｋＰａの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、
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、解砕する磁気異方性および熱的安定性に優れた希土類磁石粉末の製造方法、
（３）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前記成分組成を有する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希土類磁石合金原料を平均粒径：１０〜５００μｍになるまで粉砕処理して水素吸収処理した希土類磁石合金原料粉末を作製し、
この粉砕処理した前記希土類磁石合金原料粉末を圧力：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粉末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、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、解砕する磁気異方性および熱的安定性に優れた希土類磁石粉末の製造方法、
（４）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前記成分組成を有する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希土類磁石合金原料を平均粒径：１０〜５００μｍになるまで粉砕処理して水素吸収処理した希土類磁石合金原料粉末を作製し、
この粉砕処理した前記希土類磁石合金原料粉末を圧力：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粉末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℃の範囲内の温度で圧力：１０〜１０００ｋＰａの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、
引き続いて、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、解砕する磁気異方性および熱的安定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。
【０００７】
（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％以下に定めた。
【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り、公知である。
【００１２】
この水素吸収処理した希土類磁石合金原料に粉砕処理を施して希土類磁石合金原料粉末を作製する。その理由は、
（ａ）水素吸収処理した塊状の希土類磁石合金原料は粉砕しやすいこと、
（ｂ）水素吸収処理は温度：５００℃未満までの比較的低い温度で処理されるために高温に保持されるその他の工程で粉砕するよりも粉砕しやすいこと、
（ｃ）塊状の希土類磁石合金原料を水素吸収処理後に予め希土類磁石粉末とほぼ同じ平均粒径に粉砕してあるので、最後の粉砕工程では解砕するだけで十分に微細な希土類磁石粉末が得られ、したがって、得られた希土類磁石粉末が酸化されることが極めて少なく、また内部応力が蓄積されることが極めて少ないところから磁気異方性が一層向上すること、
（ｄ）水素粉砕後、ＨＤＤＲ処理を施すと、磁石粉末の表面凹凸が減少して平滑な表面になり、比表面積が減少するために熱的安定性が向上する、などの理由によるものである。
水素吸収処理後の希土類磁石合金原料を平均粒径：１０〜５００μｍ（一層好ましくは、５０〜４００μｍ）の範囲に粉砕する理由は、水素吸収処理した塊状の希土類磁石合金原料は比較的酸化され難いが、平均粒径：１０μｍ未満に微細に粉砕しようとすると、微細であるために粉砕時に酸化されることは避けられず、この酸化により最終的に得られる希土類磁石粉末の保磁力は低下するので好ましくなく、一方、平均粒径：５００μｍよりも大きいと、最終的に解砕して得られる希土類磁石粉末の１つの粉末粒子内の磁化容易軸が揃いにくくなって、磁気異方性が低下するので好ましくないことによるものである。水素吸収処理後に粉砕して得られる希土類磁石合金原料粉末の平均粒径は最終的に得られる希土類磁石粉末とほぼ同じ平均粒径である。
【００１３】
この粉砕処理して得られた希土類磁石合金原料粉末をさらに加熱し、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。
【００１４】
かかる水素吸収・分解処理したのち、必要に応じて中間熱処理を施す。この中間熱処理は、不活性ガスフローにより雰囲気を不活性ガス雰囲気に変えることにより適度なスピードで異方性化を促進させる工程である。この中間熱処理は圧力：１０〜１０００ｋＰａの不活性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で行なわれる。かかる中間熱処理における不活性ガス雰囲気の圧力が１０ｋＰａ未満では異方性化が速くなりすぎて保磁力低下の原因になるので好ましくなく、一方、１０００ｋＰａを越えると異方性化がほとんど進まなくなり、残留磁束密度低下の原因になるので好ましくないとされている。
【００１５】
必要に応じて中間熱処理を施したのち、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絶対圧：０．６５〜１０ｋＰａ未満（好ましくは、２〜８ｋＰａ）の水素雰囲気中または水素分圧：０．６５〜１０ｋＰａ未満（好ましくは、２〜８ｋＰａ）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熱処理する工程である。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。
【００１６】
必要に応じて中間熱処理および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。冷却した後は解砕して希土類磁石粉末とする。この解砕して得られた希土類磁石粉末は残留内部応力が極めて少ないので熱処理する必要はない。
【００１７】
【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。
【００１８】
【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に示される平均粒径になるように粉砕処理し、引き続いて表２に示される条件で水素吸収・分解処理を施し、引き続いて必要に応じて表２に示される条件で中間熱処理を行い、さらに必要に応じて表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以下に解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。
【００２０】
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、粉砕処理することなく実施例と同じ条件で水素吸収・分解処理を施し、引き続いて必要に応じて実施例と同じ条件で必要に応じて中間熱処理を行い、さらに必要に応じて表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。
【００２１】
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４に示した。
【００２２】
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４に示した。
【００２３】
また、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の磁場を圧縮方向に印加しながら外径：１０ｍｍ、高さ：７ｍｍの寸法を有する円柱状に圧縮成形し、ついでこの円柱状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の円柱状ボンド磁石を作製し、得られたボンド磁石の磁気特性をを７０ｋＯｅのパルス磁界で着磁したのち、１００℃に保持したオーブンに１０００時間放置して３時間、１００時間、１０００時間経過後の熱減磁率を測定し、その結果を表４に示して熱的安定性を評価した。
ここで、熱減磁率とは、熱減磁率（％）＝｛（所定時間暴露後の全磁束−暴露前の全磁束）／暴露前の全磁束｝×１００で求められる値である。
【００２４】
【表２】
【表３】
【表４】
表１〜表４に示される結果から、水素吸収処理を施したのち粉砕処理する本発明法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たのち粉砕処理しない従来法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、保磁力および残留磁束密度がともに向上していることが分かり、また熱減磁率が小さいところから、熱的安定性にも優れていることが分かる。
【００２８】
実施例２
表１の鋳塊ｆ〜ｊのブロックに表５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５に示される平均粒径になるように粉砕処理し、引き続いて表５に示される条件で水素吸収・分解処理を施し、引き続いて必要に応じて表５に示される条件で中間熱処理を行い、さらに必要に応じて表６に示される条件で減圧水素中熱処理を行い、さらに表６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以下に解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。
【００２９】
従来例２
表１の鋳塊ｆ〜ｊのブロックを表５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、粉砕処理することなく実施例２と同じ条件で水素吸収・分解処理を施し、引き続いて必要に応じて実施例と同じ条件で必要に応じて中間熱処理を行い、さらに必要に応じて表６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。
【００３０】
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７に示した。
また、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の磁場を圧縮方向に印加しながら外径：１０ｍｍ、高さ：７ｍｍの寸法を有する円柱状に圧縮成形し、ついでこの円柱状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の円柱状ボンド磁石を作製し、得られたボンド磁石の磁気特性をを７０ｋＯｅのパルス磁界で着磁したのち、１００℃に保持したオーブンに１０００時間放置して３時間、１００時間、１０００時間経過後の熱減磁率を測定し、その結果を表７に示して熱的安定性を評価した。
【００３１】
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７に示した。
【００３２】
【表５】
【表６】
【表７】
表１、表５、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たのち粉砕処理する本発明法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たのち粉砕処理しない従来法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、保磁力および残留磁束密度がともに向上していることが分かる。また熱減磁率が小さいところから、熱的安定性にも優れていることが分かる。
【００３６】
実施例３
表１の鋳塊ｋ〜ｏのブロックに表８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８に示される平均粒径になるように粉砕処理し、引き続いて表８に示される条件で水素吸収・分解処理を施し、引き続いて必要に応じて表８に示される条件で中間熱処理を行い、さらに必要に応じて表９に示される条件で減圧水素中熱処理を行い、さらに表９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以下に解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。
【００３７】
従来例３
表１の鋳塊ｋ〜ｏのブロックを表８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、粉砕処理することなく実施例３と同じ条件で水素吸収・分解処理を施し、引き続いて必要に応じて実施例と同じ条件で必要に応じて中間熱処理を行い、さらに必要に応じて表９に示される条件で減圧水素中熱処理を行い、さらに表９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。
【００３８】
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１０に示した。
また、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の磁場を圧縮方向に印加しながら外径：１０ｍｍ、高さ：７ｍｍの寸法を有する円柱状に圧縮成形し、ついでこの円柱状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の円柱状ボンド磁石を作製し、得られたボンド磁石の磁気特性をを７０ｋＯｅのパルス磁界で着磁したのち、１００℃に保持したオーブンに１０００時間放置して３時間、１００時間、１０００時間経過後の熱減磁率を測定し、その結果を表１０に示して熱的安定性を評価した。
【００３９】
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１０に示した。
【００４０】
【表８】
【表９】
【表１０】
表１、表８、表９および表１０に示される結果から、水素吸収処理を施したのち粉砕処理する本発明法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たのち粉砕処理しない従来法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、保磁力および残留磁束密度がともに向上していることが分かる。また熱減磁率が小さいところから、熱的安定性にも優れていることが分かる。
【００４４】
【発明の効果】
上述のように、希土類磁石合金原料を水素吸収処理→粉砕処理→水素吸収・分解処理→必要に応じて中間熱処理→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この発明の希土類磁石粉末の製造方法によると、磁気異方性および熱的安定性に優れた希土類磁石粉末を得ることができ、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 and thermal stability.
[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, if necessary, the rare earth magnet alloy raw material subjected to the hydrogen absorption / decomposition treatment is placed 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. Intermediate heat treatment is performed by holding
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: By holding in a mixed gas atmosphere of hydrogen and an inert gas of less than 0.65 to 10 kPa, heat treatment in reduced pressure hydrogen is performed while partially leaving hydrogen in the rare earth magnet alloy raw material,
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 having more excellent magnetic anisotropy, and in particular, rare earth magnet powders having more excellent magnetic anisotropy and thermal stability in both coercive force and residual magnetic flux density. Is required.
[0004]
[Means for Solving the Problems]
Therefore, the present inventors have conducted research to develop a method for producing a rare earth magnet powder having even better magnetic anisotropy and thermal stability.
(A) In the above-mentioned conventional method for producing a rare earth magnet powder having excellent magnetic anisotropy, the temperature is increased or decreased from room temperature to a predetermined temperature of less than 500 ° C. in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa. The rare earth magnet alloy raw material that has been heated and held and subjected to the hydrogen absorption treatment is pulverized to an average particle size of 10 to 500 μm to produce a hydrogen absorption treated rare earth magnet alloy raw material powder. By raising the temperature of the powder to a predetermined temperature in the range of 500 to 1000 ° C. in a hydrogen atmosphere of hydrogen pressure of 10 to 1000 kPa and holding the same, hydrogen is absorbed in the rare earth magnet alloy raw material to promote decomposition by phase transformation. Absorption / decomposition treatment is performed, and subsequently, if necessary, the rare-earth magnet alloy raw material subjected to hydrogen absorption / decomposition treatment is inert gas pressure: 1 if necessary. -Intermediate heat treatment by holding the mixture in an inert gas atmosphere at a predetermined temperature in the range of 500 to 1000 ° C. and, if necessary, further followed by intermediate heat treatment, if necessary. 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 in a mixed gas atmosphere of hydrogen and an inert gas having a hydrogen partial pressure of less than 0.65 to 10 kPa. The heat treatment is performed in reduced pressure hydrogen while keeping a part of hydrogen in the rare earth magnet alloy raw material by maintaining the pressure at 500 ° C., and then, at a predetermined temperature in the range of 500 to 1000 ° C., the vacuum pressure is maintained at an ultimate pressure: 0.13 kPa or less. The dehydrogenation process is performed to forcibly release hydrogen to promote phase transformation, and then cooled and pulverized to obtain rare earth magnet powder manufactured by the conventional manufacturing method. Magnetic anisotropy is further improved,
(B) Further, according to the method for producing a rare earth magnet powder excellent in magnetic anisotropy, if the HDDR treatment is performed after pulverizing with hydrogen, the surface irregularities of the magnet powder are reduced to a smooth surface, and the specific surface area is reduced. Thermal stability improves due to reduction,
(C) The rare earth magnet alloy raw material is in atomic% (hereinafter,% indicates atomic%),
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;
A 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 inevitable impurities, or
Rare earth magnet alloy containing R: 10 to 20%, Co: 0.1 to 50%, B: 3 to 20%, M: 0.001 to 5%, with the balance being Fe and inevitable impurities. The research results showed that it is preferable to use raw materials.
[0005]
The present invention has been made based on such research results,
(1) A rare earth magnet alloy raw material having the above-mentioned component composition, which has been homogenized at a temperature of 600 to 1200 ° C. in a vacuum or Ar gas atmosphere, if necessary, is placed in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa. Temperature from room temperature to a temperature of less than 500 ° C. or a hydrogen absorption treatment for absorbing hydrogen by raising and holding the temperature,
This hydrogen-absorbed rare earth magnet alloy raw material is pulverized to an average particle diameter of 10 to 500 μm to produce a hydrogen-absorbed rare earth magnet alloy raw material powder,
The pulverized rare earth magnet alloy raw material powder is further 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 therein, whereby hydrogen is further absorbed by the rare earth magnet alloy raw material powder. Hydrogen absorption and decomposition 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, cooling, crushing method of manufacturing rare earth magnet powder excellent in magnetic anisotropy and thermal stability,
(2) A rare earth magnet alloy raw material having the above-mentioned component composition, which has been homogenized at a temperature of 600 to 1200 ° C. in a vacuum or Ar gas atmosphere, if necessary, in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa. From a room temperature to a temperature: a hydrogen absorption treatment for absorbing hydrogen by raising the temperature to a temperature of less than 500 ° C. or raising and holding the temperature,
This hydrogen-absorbed rare earth magnet alloy raw material is pulverized to an average particle diameter of 10 to 500 μm to produce a hydrogen-absorbed rare earth magnet alloy raw material powder,
The pulverized rare earth magnet alloy raw material powder is further 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 therein, whereby hydrogen is further absorbed by the rare earth magnet alloy raw material powder. Hydrogen absorption and decomposition treatment
Subsequently, an intermediate heat treatment is performed by holding the rare earth magnet alloy raw material subjected to the hydrogen absorption / decomposition treatment in an inert gas atmosphere at a temperature in the range of 500 to 1000 ° C. and a pressure of 10 to 1000 kPa,
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, cooling, crushing method of manufacturing rare earth magnet powder excellent in magnetic anisotropy and thermal stability,
(3) The rare earth magnet alloy raw material having the above-mentioned composition, which has been homogenized under the condition of maintaining the temperature at 600 to 1200 ° C. in a vacuum or Ar gas atmosphere, if necessary, in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa. From a room temperature to a temperature: a hydrogen absorption treatment for absorbing hydrogen by raising the temperature to a predetermined temperature of less than 500 ° C., or raising and holding the temperature,
This hydrogen-absorbed rare earth magnet alloy raw material is pulverized to an average particle diameter of 10 to 500 μm to produce a hydrogen-absorbed rare earth magnet alloy raw material powder,
The pulverized rare earth magnet alloy raw material powder is further 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 therein, whereby hydrogen is further absorbed by the rare earth magnet alloy raw material powder. Hydrogen absorption and decomposition treatment
Subsequently, the rare earth magnet alloy raw material that has been subjected to the hydrogen absorption / decomposition treatment is subjected to a hydrogen atmosphere having an absolute pressure of less than 0.65 to 10 kPa or a hydrogen partial pressure of 0.65 to 10 kPa at a temperature in the range of 500 to 1000 ° C. By performing the heat treatment in reduced pressure hydrogen while keeping a part of the rare earth magnet alloy raw material by maintaining the mixed gas atmosphere of less than hydrogen and an inert gas,
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, cooling, crushing method of manufacturing rare earth magnet powder excellent in magnetic anisotropy and thermal stability,
(4) A rare earth magnet alloy raw material having the above-mentioned composition, which has been homogenized at a temperature of 600 to 1200 ° C. in a vacuum or Ar gas atmosphere, if necessary, in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa. From a room temperature to a temperature: a hydrogen absorption treatment for absorbing hydrogen by raising the temperature to a predetermined temperature of less than 500 ° C., or raising and holding the temperature,
This hydrogen-absorbed rare earth magnet alloy raw material is pulverized to an average particle diameter of 10 to 500 μm to produce a hydrogen-absorbed rare earth magnet alloy raw material powder,
The pulverized rare earth magnet alloy raw material powder is further 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 therein, whereby hydrogen is further absorbed by the rare earth magnet alloy raw material powder. Hydrogen absorption and decomposition treatment
Subsequently, an intermediate heat treatment is performed by holding the rare earth magnet alloy raw material subjected to the hydrogen absorption / decomposition treatment in an inert gas atmosphere at a temperature in the range of 500 to 1000 ° C. and a pressure of 10 to 1000 kPa,
Subsequently, the rare earth magnet alloy raw material subjected to the intermediate heat treatment is treated at a temperature within 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 of less than 0.65 to 10 kPa. By performing a heat treatment in a reduced pressure hydrogen while keeping a part of the rare earth magnet alloy raw material by maintaining the mixed gas atmosphere of the inert gas and the inert gas,
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 crushed, and is characterized by a method for producing a rare earth magnet powder excellent in magnetic anisotropy and thermal stability.
[0006]
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.
[0007]
(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% or less.
[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. Yes, it is known.
[0012]
The rare earth magnet alloy raw material that has been subjected to the hydrogen absorption processing is subjected to a pulverizing treatment to produce a rare earth magnet alloy raw material powder. The reason is,
(A) the bulk rare earth magnet alloy raw material subjected to the hydrogen absorption treatment is easily crushed;
(B) The hydrogen absorption treatment is performed at a relatively low temperature of less than 500 ° C., so that the hydrogen absorption treatment is easier to pulverize than pulverization in other steps kept at a high temperature;
(C) Since the bulk rare earth magnet alloy raw material has been previously ground to the same average particle size as the rare earth magnet powder after the hydrogen absorption treatment, a sufficiently fine rare earth magnet powder can be obtained only by crushing in the final grinding step. Therefore, the rare-earth magnet powder obtained is very unlikely to be oxidized, and the internal stress is extremely unlikely to accumulate, so that the magnetic anisotropy is further improved,
(D) When the HDDR treatment is performed after hydrogen pulverization, the surface irregularities of the magnet powder are reduced, the surface becomes smooth, and the specific surface area is reduced, so that the thermal stability is improved. .
The reason why the rare earth magnet alloy raw material after the hydrogen absorption treatment is pulverized to a range of an average particle diameter of 10 to 500 μm (more preferably, 50 to 400 μm) is that the massive rare earth magnet alloy raw material subjected to the hydrogen absorption treatment is relatively hard to be oxidized. However, if it is attempted to pulverize finely to an average particle diameter of less than 10 μm, it is inevitable that the fine particles are oxidized during the pulverization, and the coercive force of the finally obtained rare earth magnet powder is reduced by this oxidation. On the other hand, if the average particle diameter is larger than 500 μm, the axis of easy magnetization in one powder particle of the rare earth magnet powder finally obtained by crushing becomes difficult to be uniform, and the magnetic anisotropy decreases. This is because it is not preferable. The average particle size of the rare earth magnet alloy raw material powder obtained by pulverization after the hydrogen absorption treatment is substantially the same as the final obtained rare earth magnet powder.
[0013]
A hydrogen absorption / decomposition treatment in which the rare earth magnet alloy raw material powder obtained by the pulverization treatment is further heated and maintained at a predetermined temperature within a range of 500 to 1000 ° C. in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa. By applying hydrogen to the raw material, 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.
[0014]
After the hydrogen absorption / decomposition treatment, an intermediate heat treatment is performed as necessary. This intermediate heat treatment is a step of promoting anisotropy at an appropriate speed by changing the atmosphere to an inert gas atmosphere by an inert gas flow. This intermediate heat treatment is performed in an inert gas atmosphere at a pressure of 10 to 1000 kPa under the condition of maintaining a predetermined temperature within a range of 500 to 1000 ° C. If the pressure of the inert gas atmosphere in the intermediate heat treatment is less than 10 kPa, the anisotropy becomes too fast to cause a decrease in coercive force, which is not preferable. It is considered undesirable because it causes a reduction in magnetic flux density.
[0015]
After performing an intermediate heat treatment as necessary, a heat treatment in reduced pressure hydrogen is further performed as necessary. This heat treatment in reduced pressure hydrogen is performed by subjecting the rare earth magnet alloy raw material subjected to the hydrogen absorption / decomposition treatment to a hydrogen atmosphere having an absolute pressure of less than 0.65 to 10 kPa (preferably 2 to 8 kPa) or a hydrogen partial pressure of less than 0.65 to 10 kPa. This is a step of performing a heat treatment while maintaining a part of hydrogen in the rare-earth magnet alloy raw material by maintaining it in a mixed gas atmosphere of hydrogen (preferably 2 to 8 kPa) and an inert gas. By performing the heat treatment in reduced pressure hydrogen, the coercive force and the residual magnetic flux density can be further improved.
[0016]
After performing an intermediate heat treatment and a heat treatment in reduced-pressure hydrogen as necessary, a dehydrogenation treatment is performed. 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 crushed to obtain rare earth magnet powder. The rare earth magnet powder obtained by the crushing does not need to be heat-treated because the residual internal stress is extremely small.
[0017]
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.
[0018]
[Table 1]
Example 1
After subjecting the blocks of the 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 were pulverized so as to have the average particle size shown in Table 2, and subsequently The hydrogen absorption / decomposition treatment is performed under the conditions shown in Table 2, and then the intermediate heat treatment is performed under the conditions shown in Table 2 as necessary. After dehydrogenation treatment is further performed under the conditions shown in Table 3, the mixture is forcibly cooled to room temperature with Ar gas, and crushed to 300 μm or less to produce a rare earth magnet powder. 5 was performed.
[0020]
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, they were subjected to a hydrogen absorption / decomposition treatment under the same conditions as in the example without pulverization treatment, and subsequently, as necessary. After performing an intermediate heat treatment as necessary under the same conditions as in the example, further performing a heat treatment in reduced pressure hydrogen under the conditions shown in Table 3 as necessary, and further performing a dehydrogenation treatment under the conditions shown in Table 3 Conventional methods 1 to 5 were carried out by forcibly cooling to room temperature with Ar gas and pulverizing the particles to 300 μm or less to produce rare earth magnet powder.
[0021]
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. The magnetic properties of the obtained bonded magnet are shown in Table 4. It was shown to.
[0022]
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 4. .
[0023]
Also, 3% by mass of epoxy resin was added to 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, and kneaded, and a magnetic field of 1.6 MA / m was applied in the compression direction. It is compression-molded into a columnar shape having a diameter of 10 mm and a height of 7 mm, and then this columnar green compact is heat-cured in an oven at 150 ° C. for 2 hours, and has a density of 6.0 to 6.1 g / cm. After producing the columnar bonded magnet of No. 3 and magnetizing the magnetic properties of the obtained bonded magnet with a pulse magnetic field of 70 kOe, the resultant was left in an oven maintained at 100 ° C. for 1,000 hours, and then for 3 hours, 100 hours, and 1000 hours. After the lapse of time, the thermal demagnetization rate was measured, and the results are shown in Table 4 to evaluate the thermal stability.
Here, the thermal demagnetization rate is a value obtained by thermal demagnetization rate (%) = {(total magnetic flux after exposure for predetermined time−total magnetic flux before exposure) / total magnetic flux before exposure} × 100.
[0024]
[Table 2]
[Table 3]
[Table 4]
From the results shown in Tables 1 to 4, the magnetic properties of the bonded magnets and hot-pressed magnets made of the rare earth magnet powders obtained by the methods 1 to 5 of the present invention, which are subjected to the hydrogen absorption treatment and then the pulverization treatment, are as follows. Both the coercive force and the residual magnetic flux density are improved as compared with the magnetic properties of the bonded magnet and the hot-pressed magnet made of the rare earth magnet powder obtained by the conventional methods 1 to 5 which are not pulverized after the treatment. It can be seen that the thermal demagnetization rate is small, indicating that the thermal stability is excellent.
[0028]
Example 2
After subjecting the blocks of the ingots f to j in Table 1 to the hydrogen absorption treatment under the conditions shown in Table 5, the blocks subjected to the hydrogen absorption treatment were pulverized so as to have the average particle size shown in Table 5, and subsequently The hydrogen absorption / decomposition treatment is performed under the conditions shown in Table 5, and then the intermediate heat treatment is performed as necessary under the conditions shown in Table 5, and the heat treatment under reduced pressure hydrogen is further performed under the conditions shown in Table 6 as necessary. After the dehydrogenation treatment is further performed under the conditions shown in Table 6, the mixture is forcibly cooled to room temperature with Ar gas and crushed to 300 μm or less to produce a rare earth magnet powder. 10 was performed.
[0029]
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 5, the blocks were subjected to hydrogen absorption / decomposition treatment under the same conditions as in Example 2 without pulverization. Subsequently, if necessary, an intermediate heat treatment is performed under the same conditions as in the examples, a heat treatment in reduced pressure hydrogen is performed as necessary under the conditions shown in Table 6, and dehydration is further performed under the conditions shown in Table 5. After the elementary treatment, the conventional methods 6 to 10 were carried out by forcibly cooling to room temperature with Ar gas and pulverizing the particles to 300 μm or less to produce rare earth magnet powder.
[0030]
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. Table 7 shows the magnetic properties of the obtained bonded magnet. It was shown to.
Also, 3% by mass of an epoxy resin is added to 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, and kneaded, and a magnetic field of 1.6 MA / m is applied in the compression direction to form a mixture. It is compression-molded into a columnar shape having a diameter of 10 mm and a height of 7 mm, and then this columnar green compact is heat-cured in an oven at 150 ° C. for 2 hours, and has a density of 6.0 to 6.1 g / cm. After producing the columnar bonded magnet of No. 3 and magnetizing the magnetic properties of the obtained bonded magnet with a pulse magnetic field of 70 kOe, it was left for 1000 hours in an oven maintained at 100 ° C. for 3 hours, 100 hours, and 1000 hours. After the elapse, the thermal demagnetization rate was measured, and the results are shown in Table 7 to evaluate the thermal stability.
[0031]
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 7 shows the magnetic properties of the obtained hot pressed magnet. .
[0032]
[Table 5]
[Table 6]
[Table 7]
From the results shown in Table 1, Table 5, Table 6 and Table 7, the bond magnet and the hot press magnet made of the rare earth magnet powder obtained by the methods 6 to 10 of the present invention, which are subjected to the hydrogen absorption treatment and then the pulverization treatment, are performed. The magnetic properties are lower in coercive force and residual magnetic flux density than those of bonded magnets and hot pressed magnets made of rare earth magnet powders obtained by conventional methods 6 to 10 after hydrogen absorption treatment and not crushing treatment. It can be seen that it has improved. Further, it can be seen from the small thermal demagnetization rate that the thermal stability is excellent.
[0036]
Example 3
After subjecting the blocks of the ingots k to o in Table 1 to the hydrogen absorption treatment under the conditions shown in Table 8, the blocks subjected to the hydrogen absorption treatment were pulverized so as to have the average particle size shown in Table 8, and subsequently The hydrogen absorption / decomposition treatment is performed under the conditions shown in Table 8, and then the intermediate heat treatment is performed under the conditions shown in Table 8 if necessary. And then dehydrogenating under the conditions shown in Table 9, then forcibly cooled to room temperature with Ar gas, and crushed to 300 μm or less to produce rare earth magnet powders. 15 were performed.
[0037]
Conventional example 3
After subjecting the blocks of the ingots k to o in Table 1 to the hydrogen absorption treatment under the same conditions as in Example 3 shown in Table 8, the blocks were subjected to the hydrogen absorption / decomposition treatment under the same conditions as in Example 3 without pulverization. Then, if necessary, an intermediate heat treatment is performed under the same conditions as in the examples, a heat treatment in reduced pressure hydrogen is performed as necessary under the conditions shown in Table 9, and dehydration is further performed under the conditions shown in Table 9. After the elementary treatment, the conventional methods 11 to 15 were carried out by forcibly cooling to room temperature with Ar gas and pulverizing the particles to 300 μm or less to produce rare earth magnet powder.
[0038]
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 bond magnet having a density of 6.0 to 6.1 g / cm 3. Table 10 shows the magnetic properties of the obtained bond magnet. It was shown to.
Further, 3 mass% of epoxy resin was added to 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 and kneaded, and a magnetic field of 1.6 MA / m was applied in the compression direction to form the outer layer. It is compression-molded into a columnar shape having a diameter of 10 mm and a height of 7 mm, and then this columnar green compact is heat-cured in an oven at 150 ° C. for 2 hours, and has a density of 6.0 to 6.1 g / cm. After producing the columnar bonded magnet of No. 3 and magnetizing the magnetic properties of the obtained bonded magnet with a pulse magnetic field of 70 kOe, it was left for 1000 hours in an oven maintained at 100 ° C. for 3 hours, 100 hours, and 1000 hours. After the lapse of time, the thermal demagnetization rate was measured, and the results are shown in Table 10 to evaluate the thermal stability.
[0039]
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 10 shows the magnetic properties of the obtained hot pressed magnet. .
[0040]
[Table 8]
[Table 9]
[Table 10]
From the results shown in Table 1, Table 8, Table 9 and Table 10, the bond magnet and the hot press magnet made of the rare earth magnet powder obtained by the methods 11 to 15 of the present invention, which are subjected to the hydrogen absorption treatment and then the pulverization treatment, are performed. The magnetic properties are lower in coercive force and residual magnetic flux density than those of bonded magnets and hot-pressed magnets made of rare earth magnet powders obtained by conventional methods 11 to 15 which are subjected to hydrogen absorption treatment and not crushed. It can be seen that it has improved. Further, it can be seen from the small thermal demagnetization rate that the thermal stability is excellent.
[0044]
【The invention's effect】
As described above, the rare-earth element of the present invention is applied to the rare-earth magnet alloy raw material in the order of hydrogen absorption treatment → pulverization treatment → hydrogen absorption / decomposition treatment → intermediate heat treatment as required → heat treatment in reduced pressure hydrogen if necessary → dehydrogenation treatment According to the method for producing a magnet powder, a rare earth magnet powder having excellent magnetic anisotropy and thermal stability can be obtained, which has excellent industrial effects.
Claims (6)
この水素吸収処理した希土類磁石合金原料を平均粒径：１０〜５００μｍになるまで粉砕処理して水素吸収処理した希土類磁石合金原料粉末を作製し、
この粉砕処理した前記希土類磁石合金原料粉末を圧力：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粉末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、
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、解砕することを特徴とする磁気異方性および熱的安定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.
This hydrogen-absorbed rare earth magnet alloy raw material is pulverized to an average particle diameter of 10 to 500 μm to produce a hydrogen-absorbed rare earth magnet alloy raw material powder,
The pulverized rare earth magnet alloy raw material powder is further 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 therein, whereby hydrogen is further absorbed by the rare earth magnet alloy raw material powder. Hydrogen absorption and decomposition 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 and thermal stability, which is then cooled and pulverized.
この水素吸収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平均粒径：１０〜５００μｍになるまで粉砕処理して水素吸収処理した希土類磁石合金原料粉末を作製し、
この粉砕処理した前記希土類磁石合金原料粉末を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粉末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℃の範囲内の温度で圧力：１０〜１０００ｋＰａの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、
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、解砕することを特徴とする磁気異方性および熱的安定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 increasing the temperature from room temperature to a temperature of less than 500 ° C. in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa, or raising and holding the temperature.
The hydrogen-absorbed rare earth magnet alloy raw material is pulverized in a hydrogen gas atmosphere at a pressure of 10 to 1000 kPa until the average particle diameter becomes 10 to 500 μm to produce a hydrogen-absorbed rare earth magnet alloy raw material powder.
The pulverized rare earth magnet alloy raw material powder is subjected to a hydrogen absorption / decomposition treatment in which the rare earth magnet alloy raw material powder is further heated to a temperature in the range of 500 to 1000 ° C. and held to thereby further absorb and decompose hydrogen. ,
Subsequently, an intermediate heat treatment is performed by holding the rare earth magnet alloy raw material subjected to the hydrogen absorption / decomposition treatment in an inert gas atmosphere at a temperature in the range of 500 to 1000 ° C. and a pressure of 10 to 1000 kPa,
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 and thermal stability, which is then cooled and pulverized.
この水素吸収処理した希土類磁石合金原料を平均粒径：１０〜５００μｍになるまで粉砕処理して水素吸収処理した希土類磁石合金原料粉末を作製し、
この粉砕処理した前記希土類磁石合金原料粉末を圧力：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粉末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、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、解砕することを特徴とする磁気異方性および熱的安定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.
This hydrogen-absorbed rare earth magnet alloy raw material is pulverized to an average particle diameter of 10 to 500 μm to produce a hydrogen-absorbed rare earth magnet alloy raw material powder,
The pulverized rare earth magnet alloy raw material powder is further 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 therein, whereby hydrogen is further absorbed by the rare earth magnet alloy raw material powder. Hydrogen absorption and decomposition treatment
Subsequently, the rare earth magnet alloy raw material that has been subjected to the hydrogen absorption / decomposition treatment is subjected to a hydrogen atmosphere having an absolute pressure of less than 0.65 to 10 kPa or a hydrogen partial pressure of 0.65 to 10 kPa at a temperature in the range of 500 to 1000 ° C. By performing the heat treatment in reduced pressure hydrogen while keeping a part of the rare earth magnet alloy raw material by maintaining the mixed gas atmosphere of less than hydrogen and an inert gas,
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 and thermal stability, which is then cooled and pulverized.
この水素吸収処理した希土類磁石合金原料を平均粒径：１０〜５００μｍになるまで粉砕処理して水素吸収処理した希土類磁石合金原料粉末を作製し、
この粉砕処理した前記希土類磁石合金原料粉末を圧力：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粉末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℃の範囲内の温度で圧力：１０〜１０００ｋＰａの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、
引き続いて、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、解砕することを特徴とする磁気異方性および熱的安定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.
This hydrogen-absorbed rare earth magnet alloy raw material is pulverized to an average particle diameter of 10 to 500 μm to produce a hydrogen-absorbed rare earth magnet alloy raw material powder,
The pulverized rare earth magnet alloy raw material powder is further 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 therein, whereby hydrogen is further absorbed by the rare earth magnet alloy raw material powder. Hydrogen absorption and decomposition treatment
Subsequently, an intermediate heat treatment is performed by holding the rare earth magnet alloy raw material subjected to the hydrogen absorption / decomposition treatment in an inert gas atmosphere at a temperature in the range of 500 to 1000 ° C. and a pressure of 10 to 1000 kPa,
Subsequently, the rare earth magnet alloy raw material subjected to the intermediate heat treatment is treated at a temperature within 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 of less than 0.65 to 10 kPa. By performing a heat treatment in a reduced pressure hydrogen while keeping a part of the rare earth magnet alloy raw material by maintaining the mixed gas atmosphere of the inert gas and the inert gas,
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 and thermal stability, which is then cooled and pulverized.
Ｒ（ただし、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および熱的安定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, 2, 3, 4, or 5, in atomic% (hereinafter,% indicates atomic%),
R (where R represents a rare earth element containing Y; the same applies hereinafter): a rare earth magnet alloy raw material containing 10 to 20% and B: 3 to 20%, with the balance being 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.
A 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 inevitable impurities, or
Rare earth magnet alloy containing R: 10 to 20%, Co: 0.1 to 50%, B: 3 to 20%, M: 0.001 to 5%, with the balance being Fe and inevitable impurities. A method for producing a rare earth magnet powder having excellent magnetic anisotropy and thermal stability, which is a raw material.
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