JP3795694B2 - Magnetic materials and bonded magnets - Google Patents

Description

【００８０】
前記表１から明らかなように実施例３〜１０のボンド磁石は、残留磁束密度、保磁力、最大エネルギー積が大きく、優れた磁気特性を示すことがわかる。
【００８１】
（比較例１）
まず、高純度のＳｍ、Ｚｒ、Ｆｅ、Ｃｏの各原料を所定量調合し、実施例１と同様な条件で合金薄帯を作製し、真空中で熱処理した後、実施例２と同様の方法で窒化処理を施して磁性材料粉末を製造した。なお、インゴットの組成はＳｍ７．５原子％、Ｚｒ２．５原子％、Ｃｏ２７原子％、残部をＦｅとした。またＢの添加量は１４原子％となるように調整した。
【００８２】
得られた磁性材料粉末のＸ線回折を行なった結果、ＴｂＣｕ₇ 相、Ｒ₂ Ｆｅ₁₄Ｂ相及びα−Ｆｅ相の生成が確認された。また、それぞれの相のメインピークの回折強度比は、ＴｂＣｕ₇ 相：Ｒ₂ Ｆｅ₁₄Ｂ相：α−Ｆｅ相＝１９：３３：４８であった。
【００８３】
次いで、前記磁性材料粉末を用いて実施例１と同様にしてボンド磁石を製造した。得られたボンド磁石の室温における残留磁束密度、保磁力、最大エネルギー積は、それぞれ０．１２Ｔ、３２ｋＡ／ｍ、１．０ｋＪ／ｍ³ と低い磁気特性であった。これは、磁性材料中の硼素（Ｂ）の配合量が本発明の範囲（１０原子％以下）を越え、前述した粉末Ｘ線回折の結果からα−Ｆｅ相およびＲ₂ Ｆｅ₁₄Ｂ相の析出が著しいことに起因するものと考えられる。
【００８４】
（比較例２）
高純度のＳｍ、Ｚｒ、Ｆｅ、Ｃｏの各原料を所定量調合し、実施例１と同様な条件で合金薄帯を作製し、真空中で熱処理した後、実施例２と同様の方法で窒化処理を施して磁性材料粉末を製造した。なお、インゴットの組成はＳｍ７．５原子％、Ｚｒ２．５原子％、Ｃｏ２７原子％、残部がＦｅであり、Ｂは添加されていなかった。
【００８５】
得られた磁性材料粉末について、粉末のＸ線回折を行なった結果、実施例１と同様にＴｂＣｕ₇ 相が主相をなすことが確認され、ＴｂＣｕ₇ 相の格子定数比ｃ／ａは０．８６１であることがわかった。
【００８６】
次いで、前記磁性材料粉末を用いて実施例１と同様にしてボンド磁石を製造した。得られたボンド磁石の室温における残留磁束密度、保磁力、最大エネルギー積は、それぞれ０．６０Ｔ、５５０ｋＡ／ｍ、５７ｋＪ／ｍ³ であり、実施例２と比較して磁気特性が劣る。これは、Ｂの添加を行わなかったことにより、残留磁束密度が実施例２より小さく、これに起因して最大エネルギー積も実施例１より低下したものと推測される。
【００８７】
（実施例１１−１〜１１−３）
まず、高純度のＳｍ、Ｚｒ、Ｃｏ、Ｆｅの各原料を、Ａｒ雰囲気中でアーク溶解してインゴットを調製した。なお、インゴットの組成はＳｍ７．５原子％、Ｚｒ２．５原子％、Ｃｏ２７．０原子％、残部がＦｅであった。このインゴットを所定量のＢとともに石英製のノズルに装填し、アルゴンガス雰囲気中で高周波誘導加熱により溶融した後、溶湯を周速４０ｍ／ｓで回転する直径３００ｍｍの銅製の単ロール上に噴出して合金薄帯を作製した。噴出する際の温度は、１３５０℃とした。ＩＣＰによる組成分析の結果、前記合金薄帯中には１．９原子％のＢが含有され、Ｓｍ_7.4 Ｚｒ_2.4 Ｃｏ_29.8Ｂ_1.9 Ｆｅ_bal の組成を有するものであった。得られた合金薄帯の保磁力を振動試験型磁力計（ＶＳＭ）を用いて測定した。その結果、保磁力は１２〜６８ｋＡ／ｍであった。
【００８８】
次いで、保磁力が１２ｋＡ／ｍ、３６ｋＡ／ｍおよび６８ｋＡ／ｍの合金薄帯を選び、これら合金薄帯をそれぞれ不活性雰囲気（Ａｒ；０．９気圧）中、７００℃で３０分間熱処理を施した。つづいて、これら合金薄帯をボールミルにより平均粒径２０μｍ前後にそれぞれ粉砕した後、それぞれ１気圧の窒素ガス雰囲気中、４５０℃で５０時間熱処理（窒化処理）を施することにより下記表２に示す組成の３種の磁性材料粉末を合成した。
【００８９】
前記各磁性材料粉末は、Ｘ線回折の結果、全てＴｂＣｕ₇ 相が主相をなすことが確認され、その格子定数比ｃ／ａは０．８５４〜０．８７６の範囲であることがわかった。
【００９０】
前記各磁性材料粉末について、振動試験型磁力計（ＶＳＭ）を用いて磁気特性（残留磁束密度、最大エネルギー積）を調べた。なお、これらの磁気特性は磁性材料粉末の密度を７．７４ｇ／ｃｍ³ として計算し、反磁界係数０．１５として補正した結果を下記表２に示す。
【００９１】
（実施例１２〜１５）
まず、高純度のＳｍ、Ｎｂ、Ｐｒ、Ｄｙ、Ｚｒ、Ｈｆ、Ｍｎ、Ｎｉ、Ｃｒ、Ａｌ、Ｇａ、Ｍｏ、Ｗ、Ｓｉ、Ｎｂ、Ｃｏ、Ｆｅの各原料をＡｒ雰囲気中でアーク溶解した後、鋳型に注入して４種のインゴットを作製した。これらのインゴットを所定量のＢとともに石英製のノズルに装填し、アルゴンガス雰囲気中で高周波誘導加熱により溶融した後、溶湯を周速４０ｍ／ｓで回転する直径３００ｍｍの銅製の単ロール上に噴出して合金薄帯を作製した。前記各溶湯を噴出する際の温度は、１３２０℃とした。ＩＣＰによる組成分析の結果、前記各合金薄帯中には１．１原子％、１．６原子％、０．５原子％、１．７原子％のＢがそれぞれ含有され、Ｓｍ_7.9 Ｚｒ_2.2 Ｎｉ_3.3 Ｇａ_1.1 Ｃｏ_22.0Ｂ_1.1 Ｆｅ_bal.（実施例１２）、Ｓｍ_6.5 Ｎｄ_1.1 Ｚｒ_2.6 Ｍｏ_2.2 Ｃｒ_1.1 Ｓｉ_1.1 Ｃｏ_25.0Ｂ_1.6 Ｆｅ_bal.（実施例１３）、Ｓｍ_7.4 Ｐｒ_1.1 Ｚｒ_1.6 Ｈｆ_0.5 Ｗ_0.5 Ａｌ_0.2 Ｃ_2.2 Ｃｏ_33.9Ｂ_0.5 Ｆｅ_bal.（実施例１４）、Ｓｍ_7.2 Ｎｄ_0.6 Ｄｙ_2.2 Ｚｒ_2.7 Ｍｎ_1.1 Ｎｂ_1.1 Ｃｏ_26.0Ｂ_1.7 Ｆｅ_bal.（実施例１５）の組成を有するものであった。得られた各合金薄帯の保磁力を振動試験型磁力計（ＶＳＭ）を用いて測定した。その結果、実施例１２〜１５の合金薄帯の保磁力はそれぞれ２０ｋＡ／ｍ、３３ｋＡ／ｍ、２９ｋＡ／ｍ、２２ｋＡ／ｍであった。
【００９２】
次いで、前記各合金薄帯をそれぞれ不活性雰囲気（Ａｒ；０．９気圧）中、７００℃で３０分間熱処理を施した。つづいて、これら合金薄帯をボールミルにより平均粒径２０μｍ前後にそれぞれ粉砕した。ひきつづき、実施例１２、１３、１４の合金粉末をそれぞれ１気圧の窒素ガス雰囲気中、４５０℃で５０時間熱処理（窒化処理）を施することにより下記表２に示す組成の３種の磁性材料粉末を合成した。また、実施例１５の合金粉末を０．０２気圧のアンモニアガスおよび１気圧の窒素ガスの雰囲気中、３５０℃で１０時間熱処理を施することにより下記表２に示す組成の磁性材料粉末を合成した。
【００９３】
前記各磁性材料粉末は、Ｘ線回折の結果、全てＴｂＣｕ₇ 相が主相をなすことが確認され、その格子定数比ｃ／ａは０．８５４〜０．８７６の範囲であることがわかった。
【００９４】
前記各磁性材料粉末について、振動試験型磁力計（ＶＳＭ）を用いて磁気特性（残留磁束密度、最大エネルギー積）を調べた。なお、これらの磁気特性は磁性材料粉末の密度を７．７４ｇ／ｃｍ³ として計算し、反磁界係数０．１５として補正した結果を下記表２に示す。
【００９５】
【表２】

【００９６】
前記表２から明らかなように急冷直後の保磁力が５６ｋＡ／ｍ以下の合金薄帯（１２ｋＡ／ｍ、３６ｋＡ／ｍ）を用いて窒化処理することにより得られた実施例１１−１、１１−２の磁性材料粉末は、いずれも最大エネルギー積が急冷直後の保磁力が５６ｋＡ／ｍを越える合金薄帯（６８ｋＡ／ｍ）を用いて窒化処理することにより得られた実施例１１−３の磁性材料粉末に比べて大きいことがわかる。
【００９７】
また、急冷直後の保磁力が５６ｋＡ／ｍ以下の合金薄帯を用いて窒化処理することにより得られた実施例１２〜１５の磁性材料粉末は、いずれも磁気特性が優れていることがわかる。
【００９８】
なお、実施例１１−１〜１１−３の合金薄帯の作製において、保磁力が５６ｋＡ／ｍを越えるものの割合が３０％弱であったが、溶湯が噴射される銅ロールの回転速度（周速度）を４２ｍ／ｓｅｃにすることにより保磁力が５６ｋＡ／ｍを越えるものの割合を５％未満にすることができ、特に得られた合金薄帯を分別することなくそのまま加熱処理、粉砕、窒化処理等を施すことにより実施例１１−１、１１−２と同様な特性を有する磁性材料粉末を得ることができる。
【００９９】
（実施例１６−１、１６−２）
まず、高純度のＳｍ、Ｚｒ、Ｃｏ、Ｆｅの各原料を、Ａｒ雰囲気中でアーク溶解してインゴットを調製した。なお、インゴットの組成はＳｍ７．５原子％、Ｚｒ２．５原子％、Ｃｏ２７原子％、残部がＦｅであった。このインゴットを所定量のＢとともに石英製のノズルに装填し、アルゴンガス雰囲気中で高周波誘導加熱により溶融した後、溶湯を周速４０ｍ／ｓで回転する直径３００ｍｍの銅製の単ロール上に噴出して合金薄帯を作製した。噴出する際の温度は、１３５０℃とした。ＩＣＰによる組成分析の結果、前記合金薄帯中には１．９原子％のＢが含有され、Ｓｍ_7.4 Ｚｒ_2.4 Ｃｏ_29.8Ｂ_1.9 Ｆｅ_bal の組成を有するものであった。得られた複数の合金薄帯の厚さをノギスを用いて測定した。その結果、前記各合金薄帯の厚さは５〜４５μｍであった。
【０１００】
次いで、厚さが３０μｍ以下の合金薄帯および厚さが３０μｍを越える合金薄帯をそれぞれ選び、これら合金薄帯をそれぞれ不活性雰囲気（Ａｒ；０．９気圧）中、７００℃で３０分間熱処理を施した。つづいて、これら合金薄帯をボールミルにより平均粒径２０μｍ前後にそれぞれ粉砕した後、それぞれ１気圧の窒素ガス雰囲気中、４３０℃で１００時間熱処理（窒化処理）を施することにより下記表３に示す組成の２種の磁性材料粉末を合成した。
【０１０１】
前記各磁性材料粉末は、Ｘ線回折の結果、全てＴｂＣｕ₇ 相が主相をなすことが確認され、その格子定数比ｃ／ａは０．８５４〜０．８７６の範囲であることがわかった。
【０１０２】
前記各磁性材料粉末について、振動試験型磁力計（ＶＳＭ）を用いて磁気特性（残留磁束密度、最大エネルギー積）を調べた。なお、これらの磁気特性は磁性材料粉末の密度を７．７４ｇ／ｃｍ³ として計算し、反磁界係数０．１５として補正した結果を下記表３に示す。
【０１０３】
（実施例１７〜２０）
まず、高純度のＳｍ、Ｎｂ、Ｐｒ、Ｄｙ、Ｚｒ、Ｈｆ、Ｍｎ、Ｎｉ、Ｃｒ、Ａｌ、Ｇａ、Ｍｏ、Ｗ、Ｓｉ、Ｎｂ、Ｃｏ、Ｆｅの各原料をＡｒ雰囲気中でアーク溶解した後、鋳型に注入して４種のインゴットを作製した。これらのインゴットを所定量のＢとともに石英製のノズルに装填し、アルゴンガス雰囲気中で高周波誘導加熱により溶融した後、溶湯を周速４０ｍ／ｓで回転する直径３００ｍｍの銅製の単ロール上に噴出して合金薄帯を作製した。前記各溶湯を噴出する際の温度は、１３４０℃とした。ＩＣＰによる組成分析の結果、前記各合金薄帯中には１．１原子％、１．６原子％、０．５原子％、１．７原子％のＢがそれぞれ含有され、Ｓｍ_7.9 Ｚｒ_2.2 Ｎｉ_3.3 Ｇａ_1.1 Ｃｏ_22.0Ｂ_1.1 Ｆｅ_bal.（実施例１７）、Ｓｍ_6.5 Ｎｄ_1.1 Ｚｒ_2.6 Ｍｏ_2.2 Ｃｒ_1.1 Ｓｉ_1.1 Ｃｏ_25.0Ｂ_1.6 Ｆｅ_bal.（実施例１８）、Ｓｍ_7.4 Ｐｒ_1.1 Ｚｒ_1.6 Ｈｆ_0.5 Ｗ_0.5 Ａｌ_0.2 Ｃｏ_33.9Ｂ_0.5 Ｃ_2.2 Ｆｅ_bal.（実施例１９）、Ｓｍ_7.2 Ｎｄ_0.6 Ｄｙ_2.2 Ｚｒ_2.7 Ｍｎ_1.1 Ｎｂ_1.1 Ｃｏ_26.0Ｂ_1.7 Ｆｅ_bal.（実施例２０）の組成を有するものであった。得られた各合金薄帯の厚さをノギスを用いて測定した。その結果、前記各合金薄帯は下記表３に示す厚さを有していた。
【０１０４】
次いで、前記各合金薄帯をそれぞれ不活性雰囲気（Ａｒ；０．９気圧）中、７００℃で３０分間熱処理を施した。つづいて、これら合金薄帯をボールミルにより平均粒径２０μｍ前後にそれぞれ粉砕した。ひきつづき、実施例１７、１８、１９の合金粉末をそれぞれ１気圧の窒素ガス雰囲気中、４３０℃で１００時間熱処理（窒化処理）を施することにより下記表３に示す組成の３種の磁性材料粉末を合成した。また、実施例２０の合金粉末を０．０２気圧のアンモニアガスおよび１気圧の窒素ガスの雰囲気中、３５０℃で１０時間熱処理を施することにより下記表３に示す組成の磁性材料粉末を合成した。
【０１０５】
前記各磁性材料粉末は、Ｘ線回折の結果、全てＴｂＣｕ₇ 相が主相をなすことが確認され、その格子定数比ｃ／ａは０．８５４〜０．８７６の範囲であることがわかった。
【０１０６】
前記各磁性材料粉末について、振動試験型磁力計（ＶＳＭ）を用いて磁気特性（残留磁束密度、最大エネルギー積）を調べた。なお、これらの磁気特性は磁性材料粉末の密度を７．７４ｇ／ｃｍ³ として計算し、反磁界係数０．１５として補正した結果を下記表３に示す。
【０１０７】
【表３】

【０１０８】
前記表３から明らかなように急冷直後の厚さが３０μｍ以下の合金薄帯（厚さ１５〜２０μｍ）を用いて窒化処理することにより得られた実施例１６−１の磁性材料粉末は、最大エネルギー積が急冷直後の厚さが３０μｍを越える合金薄帯（厚さ３２〜３６μｍ）を用いて窒化処理することにより得られた実施例１６−２の磁性材料粉末に比べて大きいことがわかる。
【０１０９】
また、急冷直後の厚さが３０μｍ以下の合金薄帯を用いて窒化処理することにより得られた実施例１７〜２０の磁性材料粉末は、いずれも磁気特性が優れていることがわかる。
【０１１０】
（実施例２１〜３０）
まず、高純度のＳｍ、Ｚｒ、Ｃｏ、Ｂ、Ｆｅの各原料を、Ａｒ雰囲気中でアーク溶解してインゴットを調製した。なお、インゴットの組成はＳｍ７．７原子％、Ｚｒ２．５原子％、Ｃｏ２７原子％、Ｂ２．２原子％、残部がＦｅであった。このインゴットを石英製のノズルに装填し、アルゴンガス雰囲気中で高周波誘導加熱により溶融した後、溶湯を周速４５ｍ／ｓで回転する直径３００ｍｍの銅製の単ロール上に噴出して合金薄帯を作製した。噴出する際の温度は、１３６０℃とした。
【０１１１】
次いで、前記合金薄帯を石英管に真空封入し、７００℃で２０分間熱処理を施した。この熱処理合金薄帯をボールミルを用いて平均粒径３０μｍ以下に粉砕した。この合金粉末についてＸ線回折を行った。その結果、ＴｂＣｕ₇ 相が主相をなすことが確認された。また、Ｘ線回折の結果より、ＴｂＣｕ₇ 相の格子定数はａ＝０．４８６ｎｍ、ｃ＝０．４１９ｎｍと評価でき、格子定数比ｃ／ａは０．８６２であることがわかった。
【０１１２】
次いで、前記合金粉末について下記表４に示す条件で窒化処理をそれぞれ施することにより１０種の磁性材料粉末を合成した。
【０１１３】
前記各磁性材料粉末について、α−Ｆｅ相の割合および振動試験型磁力計（ＶＳＭ）を用いて最大エネルギー積を調べた。なお、α−Ｆｅ相の割合はＸ線回折から求めたα−Ｆｅ相の主反射強度（Ｉ_Fe）およびＴｂＣｕ₇ 相の主反射強度 （Ｉ_Tb）を下記式に代入することにより算出した主反射強度比（Ｉ）により評価した。
【０１１４】
Ｉ（％）＝［Ｉ_Fe／（Ｉ_Fe＋Ｉ_Tb）］×１００
また、前記最大エネルギー積は磁性材料粉末の密度を７．７４ｇ／ｃｍ³ として計算し、反磁界係数０．１５として補正した。これらの結果を下記表４に示す。
【０１１５】
【表４】

【０１１６】
前記表４から明らかなように窒化処理時の窒素圧力をｐ（気圧）、窒化処理温度をＴ（℃）とした時、ｐが２気圧以上で、かつ２ｐ＋４００≦Ｔ≦２ｐ＋４２０の関係を満たす条件で窒化処理することにより得られた実施例２１〜２８の磁性材料粉末は、最大エネルギー積が前記条件から外れる窒化処理を施すことにより得られた実施例２９、３０の磁性材料粉末に比べて高く、磁気特性がより向上されることがわかる。
【０１１７】
（実施例３１−１、３１−２）
まず、高純度のＳｍ、Ｚｒ、Ｃｏ、Ｂ、Ｆｅの各原料を、Ａｒ雰囲気中でアーク溶解してインゴットを調製した。なお、インゴットの組成はＳｍ７．７原子％、Ｚｒ２．５原子％、Ｃｏ２７原子％、Ｂ２．２原子％、残部がＦｅであった。このインゴットを石英製のノズルに装填し、アルゴンガス雰囲気中で高周波誘導加熱により溶融した後、溶湯を周速４５ｍ／ｓで回転する直径３００ｍｍの銅製の単ロール上に噴出して合金薄帯を作製した。噴出する際の温度は、１３００℃とした。
【０１１８】
次いで、前記合金薄帯を石英管に真空封入し、７００℃で２０分間熱処理を施した。つづいて、この熱処理合金薄帯をボールミルを用いて粉砕し、分級することにより下記表５に示す粒度分布を有する合金粉末（実施例３１−１）および粒径２２μｍ以下の合金粉末（実施例３１−２）を得た。実施例３１−１の合金粉末は、下記表５に示すように粒径２．８μｍ以下の微細粉末の体積比率が０．９３％であることが確認された。
【０１１９】
【表５】

【０１２０】
次いで、前記各合金粉末を１０気圧の窒素ガス雰囲気中、４４０℃で６５時間熱処理（窒化処理）を施することにより下記表６に示す組成の２種の磁性材料粉末を合成した。得られた各磁性材料粉末についてＸ線回折を行った。その結果、α−Ｆｅの回折ピークのほかはすべて回折ピークがＴｂＣｕ₇ 型結晶構造で指数付けられることが確認された。また、Ｘ線回折の結果より、ＴｂＣｕ₇ 相の格子定数はａ＝０．４９３０ｎｍ、ｃ＝０．４２５２ｎｍと評価でき、格子定数比ｃ／ａは０．８６２５であることがわかった。さらに、前記各磁性材料粉末について粒度分布測定を行った。その結果、実施例３１−１の磁性材料粉末は粒径２．８μｍ以下の微細粉末の含有量が体積比率で１．０８％、実施例３１−２の磁性材料粉末の同粒径の微細粉末の含有量が体積比率で５．３５％、であった。
【０１２１】
次いで、前記各磁性材料粉末にエポキシ樹脂を２重量％添加し混合した後、８０００ｋｇ／ｃｍ² の圧力で圧縮成型し、さらに１５０℃の温度で２．５時間キュア処理を施することにより２種のボンド磁石を製造した。
【０１２２】
得られた各ボンド磁石の室温における磁気特性（残留磁束密度、保磁力および最大エネルギー積）を測定した。その結果を下記表６に併記する。
【０１２３】
（実施例３２〜３６）
まず、高純度のＳｍ、Ｎｂ、Ｐｒ、Ｅｒ、Ｚｒ、Ｈｆ、Ｎｉ、Ｖ、Ｇａ、Ｍｏ、Ｗ、Ｓｉ、Ｂ、Ｃｏ、Ｆｅの各粉末をＡｒ雰囲気中でアーク溶解した後、鋳型に注入して５種のインゴットを作製した。これらのインゴットを石英製のノズルに装填し、アルゴンガス雰囲気中で高周波誘導加熱により溶融した後、溶湯を周速４５ｍ／ｓで回転する銅製の単ロール上に噴出して合金薄帯を作製した。前記各溶湯を噴出する際の温度は、１３１０℃とした。ＩＣＰによる組成分析の結果、前記各合金薄帯はＳｍ_6.3 Ｎｄ_2.2 Ｚｒ_2.2 Ｍｏ_2.2 Ｓｉ_1.1 Ｃｏ_22.8Ｂ_0.9 Ｆｅ_bal.（実施例３２）、Ｓｍ_7.2 Ｐｒ_1.1 Ｚｒ_2.2 Ｖ_2.2 Ｗ_1.1 Ｎｉ_3.2 Ｃｏ_17.2Ｂ_0.9 Ｆｅ_bal.（実施例３３）、Ｓｍ_8.2 Ｅｒ_1.1 Ｚｒ_1.1 Ｈｆ_1.1 Ｍｏ_2.2 Ｇａ_1.1 Ｃｏ_20.7Ｂ_0.9 Ｆｅ_bal.（実施例３４）、Ｓｍ_6.6 Ｎｄ_2.2 Ｚｒ_2.2 Ｃｏ_15.2Ｂ_1.4 Ｃ_1.1 Ｆｅ_bal.（実施例３５）、Ｓｍ_7.6 Ｎｄ_1.1 Ｚｒ_2.2 Ｃｏ_15.1Ｂ_1.9 Ｆｅ_bal.（実施例３６）の組成を有するものであった。
【０１２４】
次いで、前記各合金薄帯をそれぞれ石英管に真空封入し、７００℃で２０分間熱処理を施した。つづいて、これら熱処理合金薄帯をボールミルを用いて粉砕して合金粉末を得た。
【０１２５】
次いで、前記各合金粉末を１０気圧の窒素ガス雰囲気中、４４０℃で６５時間熱処理（窒化処理）を施することにより下記表６に示す組成の５種の磁性材料粉末を合成した。得られた各磁性材料粉末についてＸ線回折を行った。その結果、α−Ｆｅの回折ピークのほかはすべて回折ピークがＴｂＣｕ₇ 型結晶構造で指数付けられることが確認された。また、Ｘ線回折の結果より、格子定数比ｃ／ａは０．８５２〜０．８７３であることがわかった。さらに、前記各磁性材料粉末について粒度分布測定を行った。その結果、実施例３２〜３６の磁性材料粉末は粒径２．８μｍ以下の微細粉末の含有量がそれぞれ体積比率で１．０１％、１．２３％、２．０６％、０．９８％、０．９２％、であった。
【０１２６】
次いで、前記各磁性材料粉末にエポキシ樹脂を２重量％添加し混合した後、８０００ｋｇ／ｃｍ² の圧力で圧縮成型し、さらに１５０℃の温度で２．５時間キュア処理を施することにより５種のボンド磁石を製造した。
【０１２７】
得られた各ボンド磁石の室温における磁気特性（残留磁束密度、保磁力および最大エネルギー積）を測定した。その結果を下記表６に併記する。
【０１２８】
【表６】

【０１２９】
前記表６から明らかなように粒径２．８μｍ以下の微細粉末の含有割合が５体積％以下の磁性材料粉末を用いて得られた実施例３１−１のボンド磁石は、室温における残留磁束密度、保磁力および最大エネルギー積がいずれも同粒径の微細粉末の含有割合が５体積％を越える磁性材料粉末を用いて得られた実施例３１−２のボンド磁石に比べて優れていることがわかる。
【０１３０】
また、粒径２．８μｍ以下の微細粉末の含有割合が５体積％以下の磁性材料粉末を用いて得られた実施例３２〜３６のボンド磁石は、室温における残留磁束密度、保磁力および最大エネルギー積が優れていることがわかる。
【０１３１】
（実施例３７−１〜３７−５）
まず、高純度のＳｍ、Ｚｒ、Ｃｏ、Ｆｅ原料を、Ａｒ雰囲気中でアーク溶解してインゴットを調製した。インゴットの組成は、Ｓｍ７．５原子％、Ｚｒ２．５原子％、Ｃｏ２７原子％、残部をＦｅとした。このインゴットをＢとともに石英製のノズルに装填し、アルゴンガス雰囲気中で高周波誘導加熱により溶融した後、溶湯を周速４２ｍ／ｓで回転する銅製の単ロール上に噴出して合金薄帯を作製した。噴出する際の温度は、１３５０℃とした。ＩＣＰによる組成分解の結果、前記合金薄帯中には２．１６原子％のＢが含有されていることがわかった。
【０１３２】
次いで、前記合金薄帯を石英管に真空封入し、７２０℃で１５分間熱処理を施した。前記熱処理後の合金薄帯を乳鉢を用いて粒径３０μｍ以下に粉砕した後、１０気圧の窒素ガス雰囲気中、４５０℃で８０時間熱処理（窒化処理）を施して磁性材料粉末を合成した。この磁性材料粉末の組成は、Ｓｍ_6.88Ｚｒ_2.29Ｃｏ_24.77 Ｂ_1.97Ｎ_9.00Ｆｅ_bal であった。
【０１３３】
前記磁性材料粉末は、Ｘ線回折の結果より、微小なα−Ｆｅの回折ピークの他はすべての回折ピークが六方晶系のＴｂＣｕ₇ 型結晶構造にて指数付けされ、ＴｂＣｕ₇ 相が主相をなすことが確認された。また、Ｘ線回折の結果より、ＴｂＣｕ₇ 相の格子定数はａ＝０．４９２５ｎｍ、ｃ＝０．４２５８ｎｍと評価でき、格子定数比ｃ／ａは０．８６４６であることがわかった。
【０１３４】
ついで、前記ＴｂＣｕ₇ 型の磁性材料粉末と篩分けにより５０μｍ以上の粒径のみからなるＲ₂ Ｆｅ₁₄Ｂ系の磁性材料粉末（ＧＭ社製商品名；ＭＱＰ−Ｂパウダー）とを下記表７に示す割合で混合した５種の混合磁性材料粉末を調製し、これら混合磁性材料粉末にエポキシ樹脂をそれぞれ２重量％添加し混合した後、８０００ｋｇ／ｃｍ² の圧力で圧縮成型し、さらに１５０℃の温度で２．５時間キュア処理を施することにより５種のボンド磁石を製造した。
【０１３５】
得られた各ボンド磁石の嵩密度および室温における磁気特性（残留磁束密度、保磁力および最大エネルギー積）を測定した。その結果を下記表７に併記する。なお、下記表７中には前記ＴｂＣｕ₇ 型の磁性材料粉末のみを用いて製造したボンド磁石（実施例３７−６）とＲ₂ Ｆｅ₁₄Ｂ系の磁性材料粉末のみを用いて製造したボンド磁石（比較例３）の嵩密度および室温における磁気特性を併記する。
【０１３６】
【表７】

【０１３７】
前記表７から明らかなようにＴｂＣｕ₇ 型の磁性材料粉末とＲ₂ Ｆｅ₁₄Ｂ系の磁性材料粉末からなる混合磁性材料粉末を用いて製造した実施例３７−１〜３７−５のボンド磁石はＴｂＣｕ₇ 型の磁性材料粉末を用いて製造した実施例３７−６のボンド磁石に比べて充填密度が向上し、磁石の高性能化が図れたことがわかる。
【０１３８】
また、Ｒ₂ Ｆｅ₁₄Ｂ系の磁性材料粉末のみを用いて製造した比較例３のボンド磁石は腐食し易く、これに伴う磁気特性の劣化が顕著である。
【０１３９】
これに対し、ＴｂＣｕ₇ 型の磁性材料粉末とＲ₂ Ｆｅ₁₄Ｂ系の磁性材料粉末からなる混合磁性材料粉末を用いて製造した実施例３７−１〜３７−５のボンドは耐蝕性が向上される。例えば、湿度が９０％、温度８０℃の恒温恒湿槽で５０ｈの耐蝕試験を行なった後の磁気特性の変化を調べた。ＴｂＣｕ₇ 型の磁性材料粉末を５０体積％以上含むホンド磁石は、錆の発生は認められず優れた耐蝕性を示した。Ｒ₂ Ｆｅ₁₄Ｂ系の磁性材料粉末の比率が増えるにしたがって錆の発生が顕著になり、磁気特性の劣化も顕著となった。
【０１４０】
下記表８に前記表７中の実施例３７−１〜３７−３および比較例３の耐蝕試験の結果を示す。
【０１４１】
【表８】

【０１４２】
【０１４３】
【発明の効果】
以上説明したように、本発明によれば残留磁束密度が高い磁性材料を提供することができる。また、このような磁性材料を用いることにより、磁気特性の優れたボンド磁石のような永久磁石を製造することが可能となる。
【図面の簡単な説明】
【図１】本発明に用いられる合金粉末を窒化処理する際の窒素圧力と窒素吸収開始温度との関係を示す特性図。
【図２】実施例２の磁性材料粉末のＸ線回折パターンを示す特性図。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a magnetic material and a bonded magnet.
[0002]
[Prior art]
Conventionally, Sm—Co magnets, Nd—Fe—B magnets, and the like are known as high performance rare earth permanent magnets, and are currently being mass-produced. These magnets contain a large amount of Fe or Co and contribute to an increase in saturation magnetic flux density. Moreover, the rare earth elements in these magnets bring about a very large magnetic anisotropy derived from the behavior of 4f electrons in the crystal field. As a result, the coercive force is increased and a high-performance magnet is realized. Such high-performance magnets are mainly used in electrical equipment such as speakers, motors, and measuring instruments.
[0003]
In recent years, there has been an increasing demand for miniaturization of various electric devices, and in order to meet this demand, there has been a demand for higher performance permanent magnets by improving the maximum magnetic energy product of the permanent magnets.
[0004]
On the other hand, the present inventors have made TbCu₇In a magnetic material having a phase as a main phase, a magnetic material having a high Fe concentration in the main phase and a high saturation magnetic flux density has been proposed (Japanese Patent Application No. 4-277474).
[0005]
[Problems to be solved by the invention]
TbCu with such high Fe concentration₇There is a demand for further increase in residual magnetic flux density even in a magnetic material having a phase as a main phase. TbCu with high Fe concentration₇In order to give a large coercive force to a magnetic material whose phase is a main phase, it is effective to employ a manufacturing process such as liquid quenching or mechanical alloying. However, the magnetic material that has undergone these processes has fine crystal grains, and crystal orientation in the easy axis direction of magnetization is difficult by a simple process such as normal magnetic field orientation. As a result, there is a problem that a magnetic material having a large residual magnetic flux density cannot be obtained.
[0006]
In the present invention, the main phase is TbCu₇It is intended to provide a magnetic material having a high residual magnetic flux density.
[0007]
  In addition, the present invention is intended to provide a bonded magnet having a main phase as a phase and including a free amount having a high residual magnetic flux density.
[0008]
[Means for Solving the Problems]
  The magnetic material according to the present invention has the general formula
        R1_xR2_yB_zM_100-xyz
    However, R1 is at least one kind of rare earth elements (including Y), 50 atomic% or more is Sm, R2 is ZrandAt least one element selected from Hf, M isFe alone or Fe and Fe with 50 atomic% or moreThe elements x, y, and z are represented by atomic percentages of 2 ≦ x, 4 ≦ x + y ≦ 20, and 0.001 ≦ z ≦ 10, respectively, and the main phase is TbCu₇It has a type crystal structure.
[0009]
In an isotropic magnetic material, when individual crystal grains behave independently, the ratio (Br / Bs) of residual magnetic flux density (Br) to saturation magnetic flux density (Bs) generally does not exceed 0.5. However, if the refined crystal grains are bonded by exchange interaction through the crystal grain boundary, the Br / Bs may exceed 0.5 even for an isotropic magnetic material.
[0010]
TbCu₇In the magnetic material according to the present invention represented by the above general formula containing the phase as a main phase and containing boron (B), the exchange interaction between crystal grains is increased, so that the residual magnetic flux density is improved. This is considered to be due to the behavior of boron described below. Boron is, for example, TbCu₇It is incorporated into the magnetic material in such a way that it enters the interstitial position of the phase or forms a grain boundary phase by combining with a rare earth element or a transition metal element. The incorporation of boron into such a magnetic material enhances the exchange interaction between crystal grains by refining the crystal grains or affecting the grain boundary structure, and the Br / Bs exceeds 0.5. The properties can be expressed, and the residual magnetic flux density of the magnetic material can be improved.
[0011]
  The bonded magnet according to the present invention has a general formula
        R1_xR2_yB_zM_100-xyz
  However, R1 is at least one element selected from rare earth elements including Y, 50 atomic% or more is Sm, R2 is ZrandAt least one element selected from Hf, M isFe alone or Fe and Fe with 50 atomic% or moreThe elements, x, y, and z are each expressed in terms of atomic percent x ≧ 2, 4 ≦ x + y ≦ 20, 0.001 ≦ z ≦ 10, and the main phase is TbCu₇A magnetic material powder having a type crystal structure;
  With binder
It is characterized by including.
[0012]
Since such a bonded magnet includes a magnetic material having a high residual magnetic flux density, it has a large maximum energy product.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
The magnetic material of the present invention has a general formula
R1_xR2_yB_zA_uM_100-xyzu
Where R1 is at least one rare earth element (including Y), R2 is at least one element selected from Zr, Hf and Sc, A is at least one element selected from H, N, C and P, and M is Fe And at least one element of Co, x, y, z, and u are represented by atomic%, indicating 2 ≦ x, 4 ≦ x + y ≦ 20, 0.001 ≦ z ≦ 10, and 0 ≦ u ≦ 20, respectively. , The main phase is TbCu₇Has a crystalline structure.
[0014]
The main phase is the phase with the largest occupation in the magnetic material, and the TbCu₇The main phase having a type crystal structure bears magnetic properties. For this reason, when the content ratio of the main phase in the magnetic material of the present invention is lowered, the characteristics of the main phase are not reflected. Therefore, it is desirable to have a content ratio of at least 50% by volume or more.
[0015]
In the magnetic material according to the present invention, the TbCu₇The ratio c / a of the lattice constants a and c of the type crystal structure is preferably 0.847 or more. The c / a is TbCu₇It is closely related to the Fe and Co concentrations in the phase, and the Fe and Co concentrations increase with increasing c / a. TbCu₇An increase in the Fe and Co concentrations in the phase leads to an increase in the saturation magnetic flux density and can improve the magnetic properties. Such an effect is particularly remarkable in a magnetic material having c / a of 0.847 or more. The value of c / a can be controlled by the ratio of components constituting the magnetic material or the manufacturing method.
[0016]
Next, (1) the reason why the action of each component constituting the magnetic material of the above general formula and the blending amount of each component are specified, (2) the method for producing a magnetic material not containing A element, (3) The manufacturing method of the magnetic material which mix | blended N, (4) The manufacturing method of the magnetic material which mix | blended C as A element, (5) The manufacturing method of a magnet is demonstrated in detail.
[0017]
(1) Reasons for defining the function of each component constituting the magnetic material of the above general formula and the blending amount of each component
(1-1) R1 element
Examples of the rare earth element as the R1 element include La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Lu, and Y. These are one kind or a mixture of two or more kinds. Used in. The R1 element brings a large magnetic anisotropy to the magnetic material and imparts a high coercive force. In particular, it is preferable that 50 atomic% or more of the R1 element is Sm. In this case, the remainder other than Sm is preferably Pr or Nd.
[0018]
When the R1 element is less than 2 atomic%, it is difficult to obtain a magnetic material having a remarkably large coercive force with a decrease in magnetic anisotropy. On the other hand, when the R1 element is mixed excessively, the saturation magnetic flux density of the magnetic material is lowered. Therefore, the R1 element content x is preferably 4 ≦ x ≦ 16.
[0019]
(1-2) R2 element
As the R2 element, at least one element selected from the group consisting of Zr, Hf and Sc can be used. Such an R2 element mainly occupies the rare-earth site of the main phase, and reduces the average atomic radius of the rare-earth site.₇It becomes possible to increase the Fe and Co concentrations in the mold phase. The preferable content y of R2 element is 0.1 ≦ y ≦ 10, more preferably 1 ≦ y ≦ 3.
[0020]
Further, if the total amount of the R1 element and the R2 element is less than 4 atomic%, it is difficult to obtain a magnetic material having a coercive force in which the precipitation of α-Fe (Co) is extremely large. On the other hand, when the total amount of the R1 element and the R2 element exceeds 20 atomic%, the saturation magnetic flux density of the magnetic material decreases. The total content (x + y) of the R1 element and the R2 element is more preferably 4 ≦ x + y ≦ 16.
[0021]
(1-3) B (boron)
Boron is an effective element for obtaining a magnetic material having a high residual magnetic flux density, which is an object of the present invention. When the boron content is less than 0.001 atomic%, it is difficult to obtain a magnetic material having a high residual magnetic flux density. On the other hand, if the boron content exceeds 10 atomic%, R₂Fe₁₄The generation of the B phase becomes remarkable, and the magnetic properties of the magnetic material are deteriorated. The boron content z is preferably 0.01 ≦ z ≦ 4, more preferably 0.1 ≦ z ≦ 3.
[0022]
(1-4) Element A
The element A is at least one element selected from H, N, C, and P. The A element exists mainly at interstitial positions of the main phase, and has a function of improving the Curie temperature and magnetic anisotropy of the main phase as compared with the case where the A element is not included.
[0023]
The effect of the element A is exhibited with a small amount of compounding, but when it exceeds 20 atomic%, α-Fe (Co) precipitates more. A more preferable content u of the element A is 2 ≦ u ≦ 20, and further preferably 5 ≦ u ≦ 10.
[0024]
(1-5) M element
The M element is at least one element selected from Fe and Co, and has a function of increasing the saturation magnetic flux density of the magnetic material. The saturation magnetic flux density is effectively increased by containing 70 atomic% or more of the M element in the magnetic material.
[0025]
A part of the M element is allowed to be replaced with at least one T element selected from Cr, V, Mo, W, Mn, Ni, Sn, Ga, Al, and Si. Such substitution of the T element makes it possible to increase the proportion of the main phase in the entire magnetic material or increase the total amount of M and T in the main phase. In addition, the coercivity of the magnetic material can be increased.
[0026]
However, if a large amount of the M element is substituted with the T element, the saturation magnetic flux density is reduced. For this reason, it is desirable that the substitution amount of the T element is atomic% and 20% or less of the M element. Further, from the viewpoint of obtaining a magnetic material having a high saturation magnetic flux density, the amount of Fe in the total amount of M element and T element is preferably 50 atomic% or more.
[0027]
The magnetic material according to the present invention is allowed to contain inevitable impurities such as oxides.
[0028]
(2) Manufacturing method of magnetic material
(2-1) First, an ingot containing a predetermined amount of each of the elements R1, R2, and M and, if necessary, a T element that replaces a part of the M element is prepared by arc melting or high frequency melting. The ingot is cut into small pieces and melted together with a predetermined amount of boron (B) by high-frequency induction heating or the like, and then the molten metal is ejected onto a single roll rotating at a high speed to produce a quenched ribbon. It is also possible to produce a quenched ribbon from this molten metal by previously containing boron in the ingot.
[0029]
If the temperature of the molten metal is too high, R₂Fe₁₄There is a possibility that the B phase is formed in the quenched ribbon. For this reason, it is preferable that the temperature of the said molten metal shall be 900 to 1500 degreeC.
[0030]
As the liquid quenching method, means such as a twin roll method, a rotating disk method, and a gas atomizing method may be used in addition to the single roll method.
[0031]
(2-2) Mechanical energy is applied to a mixture of each raw material powder of a predetermined amount of each of R1, R2, B, and M and, if necessary, T element that replaces part of the M element. Magnetic materials are produced by mechanical alloying or alloying by alloying by phase reaction.
[0032]
In the method for producing the magnetic material, it is desirable that the quenching step and the solid phase reaction step are performed in an inert gas atmosphere such as Ar or He. By rapid cooling or solid phase reaction in such an atmosphere, it is possible to produce a magnetic material in which deterioration of magnetic properties due to oxidation is prevented.
[0033]
The magnetic material obtained by the above method allows heat treatment at 300 to 1000 ° C. for 0.1 to 10 hours in an inert gas atmosphere such as Ar or He or in vacuum as necessary. By performing such heat treatment, it becomes possible to improve magnetic characteristics such as coercive force.
[0034]
(3) Manufacturing method of magnetic material containing N as element A
First, the alloy material obtained by the above methods (2-1) and (2-2) is pulverized to an average particle size of several μm to several hundred μm by a ball mill, a brown mill, a stamp mill, a jet mill, etc. Is magnetically treated in a nitrogen gas atmosphere to produce a magnetic material. However, since the alloy material manufactured by the mechanical alloying method or the mechanical grinding method as in the method (2) is in a powder state, the pulverization step can be omitted.
[0035]
When the alloy material (thin ribbon) obtained by the liquid quenching method of (1) above is used as the raw material for the alloy powder to be subjected to the nitriding treatment, the coercive force (iHc) immediately after quenching is 56 kA / m (700 Oe). ), More preferably 20 kA / m (250 Oe) or less, or it is desirable to use a ribbon having a thickness of 30 μm or less. For example, when the single roll method is adopted as the liquid quenching method, the former thin ribbon is obtained by increasing the rotation speed of the roll. For example, when the single roll method is adopted as the liquid quenching method, the latter ribbon is obtained by adjusting the gap between the nozzle for injecting the molten metal and the single roll. By nitriding the alloy powder obtained by pulverizing such a ribbon, a magnetic material having a further improved residual magnetic flux density can be obtained.
[0036]
The nitriding treatment is preferably performed at a temperature of 200 to 700 ° C. in a nitrogen gas atmosphere of 0.001 to 100 atm. The nitriding treatment under such pressure and temperature may be performed for 0.1 to 300 hours.
[0037]
In particular, when the nitrogen pressure during nitriding is p (atmospheric pressure) and the nitriding temperature is T (° C.), it is preferable that p is 2 atm or more and 2p + 400 ≦ T ≦ 2p + 420 is satisfied.
[0038]
That is, the present inventors have found that there is a relationship shown in FIG. 1 between the nitrogen pressure and the nitrogen absorption start temperature when nitriding the alloy powder. Here, the nitrogen absorption start temperature is a temperature at which nitrogen absorption occurs when the temperature is raised from room temperature in a nitrogen-containing gas. The temperature at which the α-Fe phase starts to precipitate in the magnetic material is substantially equal to the nitrogen absorption start temperature. Therefore, when the nitrogen pressure is increased, even if nitriding is performed at a higher temperature than when the nitrogen pressure is low, α It is possible to reduce the precipitation of the -Fe phase. Therefore, by performing nitriding treatment under the above conditions, it is possible to easily diffuse nitrogen into the alloy powder and to obtain a magnetic material with good magnetic properties while suppressing the precipitation of excess α-Fe phase. become.
[0039]
However, if the temperature is set to T <2p + 400 under the condition that the nitrogen pressure is 2 atm or more, the amount of nitrogen absorbed per unit time is small even if nitriding is performed, and the nitriding time may be long, leading to an increase in cost. is there. On the other hand, if the temperature is set to T> 2p + 420 under the condition where the nitrogen pressure is 2 atm or more, the α-Fe phase precipitates even if the nitrogen pressure is increased, which may deteriorate the magnetic properties of the magnetic material.
[0040]
The atmosphere of the nitriding treatment may use nitrogen compound gas such as ammonia instead of nitrogen gas. By using this ammonia, the nitriding reaction rate can be increased.
[0041]
By performing heat treatment at a temperature of 100 to 700 ° C. in a hydrogen gas atmosphere of 0.001 to 100 atm as a pre-process of the nitriding treatment, or by using a gas in which hydrogen is mixed with nitrogen gas, high-efficiency nitriding It becomes possible to do.
[0042]
In the nitriding treatment, another gas not containing nitrogen can be mixed. However, when oxygen is mixed, the oxygen partial pressure is set to 0 in order to avoid deterioration of magnetic properties due to oxide formation during the heat treatment. It is desirable that the pressure be 0.02 atm or less.
[0043]
In the process of preparing the alloy powder, a nitrogen compound such as RN (R is at least one selected from R1 and R2 described above) is used as a raw material, and nitrogen is added as the element A by preparing it by solid phase reaction. It is also possible to produce a magnetic material.
[0044]
(4) Method for producing magnetic material containing C as element A
First, the alloy material obtained by the above methods (2-1) and (2-2) is pulverized to an average particle size of several μm to several hundred μm by a ball mill, a brown mill, a stamp mill, a jet mill, etc. Is magnetically treated in an atmosphere of a carbon-containing gas such as methane to produce a magnetic material in which carbon is incorporated. However, since the alloy material manufactured by the mechanical alloying method or the mechanical grinding method as in the method (2) is in a powder state, the pulverization step can be omitted.
[0045]
When the alloy material (thin ribbon) obtained by the liquid quenching method of (1) above is used as the raw material for the alloy powder to be heat-treated, the coercive force (iHc) immediately after quenching is 56 kA / m (700 Oe). Hereinafter, it is desirable to use a ribbon having a thickness of 20 kA / m (250 Oe) or less or a thickness of 30 μm or less. A magnetic material having a further improved residual magnetic flux density can be obtained by heat-treating the alloy powder obtained by pulverizing such a ribbon in an atmosphere of a carbon-containing gas.
[0046]
The heat treatment is preferably performed at a temperature of 200 to 700 ° C. in an atmosphere of a carbon-containing gas at 0.001 to 100 atm. The heat treatment under such pressure and temperature may be performed for 0.1 to 300 hours.
[0047]
In addition to using the carbon-containing gas such as methane, the magnetic material containing C as the element A can be produced by adding carbon in the alloy preparation stage.
[0048]
In addition, the magnetic material which mix | blended phosphorus as A element can be manufactured by adding phosphorus in the preparation stage of an alloy.
[0049]
(5) Manufacturing method of permanent magnet
When manufacturing a permanent magnet, an alloy powder obtained by pulverizing the magnetic material is usually used. However, when pulverization has already been performed in the manufacturing process of the magnetic material, this can be omitted. Using such an alloy powder, a permanent magnet is manufactured by the following method.
[0050]
(5-1) A bonded magnet is manufactured by mixing the alloy powder with a binder and compression molding.
[0051]
As the alloy powder, it is desirable to use a fine powder having a particle size of 2.8 μm or less having a content of 5% by volume or less, more preferably 2% by volume or less. Such a fine alloy powder has a large specific surface area, so that it is easily oxidized and α-Fe is easily generated by a solid-gas reaction. For this reason, it is possible to obtain a bonded magnet with improved magnetic properties by using an alloy powder that does not contain the fine alloy powder.
[0052]
In order to remove the fine powder in the alloy powder, for example, a method of classifying the alloy powder using an airflow disperser or a method of dispersing the alloy powder in a solvent and removing suspended particles is adopted. be able to.
[0053]
As the binder, for example, a synthetic resin such as epoxy resin or nylon can be used. When a thermosetting resin such as an epoxy resin is used as the synthetic resin, it is preferable to perform a curing treatment at a temperature of 100 to 200 ° C. after compression molding. When a thermoplastic resin such as nylon is used as the synthetic resin, it is desirable to use an injection molding method.
[0054]
In the compression molding step, it is possible to obtain a bonded magnet having a high magnetic flux density by applying a magnetic field to align the crystal orientation of the alloy powder.
[0055]
In the bonded magnet, R₂Fe₁₄It is allowed to include a magnetic material powder having a B phase (where R represents at least one element selected from rare earth elements including Y) as a main phase.
[0056]
General formula R1_xR2_yB_zA_uM_100-xyzuWhen nitriding the alloy powder of (u = 0), the powder particle size is preferably small, for example, about 50 μm or less, more preferably about 30 μm or less, in order to sufficiently and uniformly nitride the inside of the powder. However, as described above, it is preferable to use an alloy powder in which the content of a fine powder having a particle size of 2.8 μm or less that increases the specific surface area is 5% by volume or less. However, when a bonded magnet is manufactured using such fine powder of 50 μm or less, it is difficult to increase the filling rate. As a result, it becomes difficult to improve the magnetic properties of the bonded magnet.
[0057]
Meanwhile, the R₂Fe₁₄When the B-type magnetic material is pulverized too finely, the magnetic properties deteriorate. Accordingly, R having a relatively large particle size, for example, a particle size of about 50 μm or more.₂Fe₁₄B-type powder and the general formula R1 having a smaller particle size_xR2_yB_zA_uM_100-xyzuBy mixing and using this powder, the filling rate can be improved, and as a result, a bonded magnet having excellent magnetic properties can be obtained.
[0058]
General formula R1_xR2_yB_zA_uM_100-xyzuAlloy powder (A) represented by₂Fe₁₄The mixing ratio of the alloy powder (B) having the B phase as the main phase is preferably such that A / B is 0.1 to 10 by weight. When the A / B is less than 0.1, the amount of the alloy powder (A) having excellent magnetic properties such as the residual magnetic flux density in the bonded magnet is reduced, and it is difficult to sufficiently enhance the magnetic properties. . On the other hand, if the A / B exceeds 10, it becomes difficult to improve the close-packing property of the bonded magnet.
[0059]
(5-2) After the alloy powder is mixed with a low melting point metal or a low melting point alloy, a metal bond magnet is manufactured by compression molding.
[0060]
Examples of the low melting point metal include metals such as Al, Pb, Sn, Zn, Cu, and Mg, and the alloy may be an alloy of the metal.
[0061]
In the compression molding step, a metal bond magnet having a high magnetic flux density can be obtained by applying a magnetic field to align the crystal orientation of the alloy powder.
[0062]
(5-3) A permanent magnet is manufactured by integrating the alloy powder as a high-density molded body by hot pressing or hot isostatic pressing (HIP).
[0063]
In the pressurizing step, a permanent magnet having a high magnetic flux density can be produced by applying a magnetic field to align the crystal orientation of the alloy powder.
[0064]
By performing plastic deformation while pressing at a temperature of 300 to 700 ° C. after the pressing step, it becomes possible to manufacture a permanent magnet in which the alloy powder is oriented in the easy axis direction.
[0065]
(5-4) A permanent magnet is manufactured by sintering the alloy powder.
[0066]
【Example】
Hereinafter, embodiments of the present invention will be described in detail.
[0067]
(Example 1)
First, high purity Sm, Zr, Co, and Fe raw materials were arc-melted in an Ar atmosphere to prepare an ingot. The composition of the ingot was Sm 7.5 atomic%, Zr 2.5 atomic%, Co 27 atomic%, and the balance was Fe. This ingot is cut into small pieces of about 20 g, loaded into a quartz nozzle together with about 60 mg of B, melted by high-frequency induction heating in an argon gas atmosphere, and then a single copper roll rotating the molten metal at a peripheral speed of 40 m / s. An alloy ribbon was produced by jetting upward. The temperature at the time of ejection was 1300 ° C. As a result of compositional decomposition by ICP, the alloy ribbon contains 1.88 atomic% of B, and Sm_7.35Zr_2.45Co_26.5B_1.88Fe_balIt had the composition of this. Subsequently, the alloy ribbon was vacuum sealed in a quartz tube and heat treated at 720 ° C. for 15 minutes.
[0068]
The formed phase in the alloy ribbon after the heat treatment was examined by X-ray diffraction. As a result, on the diffraction pattern, all diffraction peaks other than the minute α-Fe diffraction peak are hexagonal TbCu.₇Indexed by the type crystal structure, TbCu₇It was confirmed that the phase was the main phase. From the result of X-ray diffraction, TbCu₇The lattice constants of the phases could be evaluated as a = 0.4853 nm and c = 0.4184 nm, and the lattice constant ratio c / a was found to be 0.8621.
[0069]
The alloy ribbon after the heat treatment was pulverized to a particle size of 100 μm or less using a mortar, and 2 wt% of an epoxy resin was added to the magnetic material powder and mixed, and then 8000 kg / cm.²The bonded magnet was manufactured by compressing and molding at a pressure of 150 ° C., followed by curing at a temperature of 150 ° C. for 2.5 hours.
[0070]
As a result of measuring the magnetic properties at room temperature of the obtained bonded magnet, the residual magnetic flux density, coercive force and maximum energy product were 0.75 T, 210 kA / m, and 64 kJ / m, respectively.^ThreeMet.
[0071]
(Example 2)
The alloy ribbon of Example 1 was vacuum sealed in a quartz tube and heat treated at 720 ° C. for 15 minutes. The heat-treated material was pulverized to a particle size of 32 μm or less using a mortar, and then subjected to heat treatment (nitriding treatment) at 440 ° C. for 65 hours in a nitrogen gas atmosphere of 1 atm to synthesize magnetic material powder. The composition of this magnetic material powder is Sm_6.76Zr_2.25Co_24.35B_1.70N_8.12Fe_balMet.
[0072]
The produced phase in the magnetic material powder was measured by X-ray diffraction to obtain the X-ray diffraction pattern shown in FIG. As shown in FIG. 2, on the diffraction pattern, all diffraction peaks other than the minute α-Fe diffraction peak are hexagonal TbCu.₇Indexed by the type crystal structure, TbCu₇It was confirmed that the phase was the main phase. From the result of X-ray diffraction, TbCu₇The lattice constant of the phase could be evaluated as a = 0.4927 nm and c = 0.4255 nm, and the lattice constant ratio c / a was found to be 0.8636.
[0073]
Next, the magnetic material powder was suspended in ethanol, and the suspended matter was removed to remove fine powder having a particle size of 3.8 μm or less to 5% by volume or less. After adding 2% by weight of epoxy resin to the magnetic material powder after fine powder removal and mixing, 8000 kg / cm²Then, a bonded magnet was manufactured by compression molding at a pressure of 150 ° C. and then cured at a temperature of 150 ° C. for 2.5 hours.
[0074]
As a result of measuring the magnetic properties at room temperature of the obtained bonded magnet, the residual magnetic flux density, coercive force and maximum energy product were 0.75 T, 560 kA / m, and 81 kJ / m, respectively.^ThreeMet.
[0075]
(Examples 3 to 10)
First, 8 types of high-purity Sm, Nb, Pr, Dy, Zr, Hf, V, Ni, Cr, Al, Ga, Mo, W, Si, Co, and Fe are arc-melted in an Ar atmosphere. An ingot was prepared. Subsequently, these small pieces of ingot are loaded into quartz nozzles together with boron (B), melted by high-frequency induction heating in an argon gas atmosphere, and then a single copper roll that rotates the molten metal at a peripheral speed of 40 m / s. Eight types of alloy ribbons were produced by jetting up. These alloy ribbons are vacuum sealed in a quartz tube, heat treated at 720 ° C. for 15 minutes, further pulverized to a particle size of 32 μm or less using a mortar, and then heat treated at 440 ° C. for 65 hours in a nitrogen gas atmosphere at 1 atmosphere. By applying (nitriding treatment), eight kinds of magnetic material powders having compositions shown in Table 1 below were synthesized.
[0076]
The magnetic material powders are all TbCu as a result of X-ray diffraction.₇It was confirmed that the phase was the main phase, and the lattice constant ratio c / a was found to be in the range of 0.854 to 0.876.
[0077]
Next, eight types of bonded magnets were manufactured by the same method as in Example 2 using the magnetic material powder.
[0078]
Each bond magnet obtained was examined for residual magnetic flux density at room temperature, coercive force, and maximum energy product. These results are also shown in Table 1 below.
[0079]
[Table 1]

[0080]
As is apparent from Table 1, the bonded magnets of Examples 3 to 10 have large residual magnetic flux density, coercive force, and maximum energy product, and show excellent magnetic characteristics.
[0081]
(Comparative Example 1)
First, a predetermined amount of high-purity Sm, Zr, Fe, and Co raw materials are prepared, an alloy ribbon is prepared under the same conditions as in Example 1, heat treated in a vacuum, and then the same method as in Example 2 Was subjected to nitriding treatment to produce a magnetic material powder. The composition of the ingot was Sm 7.5 atomic%, Zr 2.5 atomic%, Co 27 atomic%, and the balance was Fe. The amount of B added was adjusted to 14 atom%.
[0082]
As a result of X-ray diffraction of the obtained magnetic material powder, TbCu₇Phase, R₂Fe₁₄Formation of B phase and α-Fe phase was confirmed. The diffraction intensity ratio of the main peak of each phase is TbCu₇Phase: R₂Fe₁₄B phase: α-Fe phase = 19: 33: 48.
[0083]
Next, a bonded magnet was manufactured in the same manner as in Example 1 using the magnetic material powder. The resultant bonded magnet has a residual magnetic flux density, a coercive force, and a maximum energy product at room temperature of 0.12 T, 32 kA / m, and 1.0 kJ / m, respectively.^ThreeAnd low magnetic properties. This is because the amount of boron (B) in the magnetic material exceeds the range of the present invention (10 atomic% or less), and the α-Fe phase and R are obtained from the results of the above-mentioned powder X-ray diffraction.₂Fe₁₄This is probably due to the remarkable precipitation of the B phase.
[0084]
(Comparative Example 2)
Predetermined amounts of high-purity Sm, Zr, Fe, and Co raw materials are prepared, an alloy ribbon is prepared under the same conditions as in Example 1, heat treated in vacuum, and then nitrided in the same manner as in Example 2. The magnetic material powder was manufactured by processing. The composition of the ingot was Sm 7.5 atom%, Zr 2.5 atom%, Co 27 atom%, the balance was Fe, and B was not added.
[0085]
As a result of X-ray diffraction of the obtained magnetic material powder, TbCu was obtained in the same manner as in Example 1.₇The phase is confirmed to be the main phase and TbCu₇The lattice constant ratio c / a of the phase was found to be 0.861.
[0086]
Next, a bonded magnet was manufactured in the same manner as in Example 1 using the magnetic material powder. The resultant bonded magnet has a residual magnetic flux density, a coercive force, and a maximum energy product at room temperature of 0.60 T, 550 kA / m, and 57 kJ / m, respectively.^ThreeIn comparison with Example 2, the magnetic properties are inferior. This is presumed that the residual magnetic flux density was smaller than that in Example 2 because B was not added, and the maximum energy product was also lower than that in Example 1 due to this.
[0087]
(Examples 11-1 to 11-3)
First, high purity Sm, Zr, Co, and Fe raw materials were arc-melted in an Ar atmosphere to prepare an ingot. The composition of the ingot was Sm 7.5 atomic%, Zr 2.5 atomic%, Co 27.0 atomic%, and the balance was Fe. This ingot is loaded into a quartz nozzle together with a predetermined amount of B, melted by high-frequency induction heating in an argon gas atmosphere, and then the molten metal is ejected onto a single 300 mm diameter copper roll rotating at a peripheral speed of 40 m / s. An alloy ribbon was prepared. The temperature at the time of ejection was 1350 ° C. As a result of composition analysis by ICP, the alloy ribbon contains 1.9 atomic% of B, and Sm_7.4Zr_2.4Co_29.8B_1.9Fe_balIt had the composition of this. The coercive force of the obtained alloy ribbon was measured using a vibration test type magnetometer (VSM). As a result, the coercive force was 12 to 68 kA / m.
[0088]
Next, alloy ribbons having a coercive force of 12 kA / m, 36 kA / m and 68 kA / m were selected, and each of these alloy ribbons was heat-treated at 700 ° C. for 30 minutes in an inert atmosphere (Ar; 0.9 atm). did. Subsequently, these alloy ribbons were each pulverized to a mean particle size of about 20 μm by a ball mill and then subjected to heat treatment (nitriding treatment) at 450 ° C. for 50 hours in a nitrogen gas atmosphere of 1 atm. Three kinds of magnetic material powders having compositions were synthesized.
[0089]
The magnetic material powders are all TbCu as a result of X-ray diffraction.₇It was confirmed that the phase was the main phase, and the lattice constant ratio c / a was found to be in the range of 0.854 to 0.876.
[0090]
About each said magnetic material powder, the magnetic characteristic (residual magnetic flux density, maximum energy product) was investigated using the vibration test type magnetometer (VSM). In addition, these magnetic characteristics have a density of the magnetic material powder of 7.74 g / cm.^ThreeTable 2 below shows the results calculated and corrected as the demagnetizing factor 0.15.
[0091]
(Examples 12 to 15)
First, after arc melting each raw material of high purity Sm, Nb, Pr, Dy, Zr, Hf, Mn, Ni, Cr, Al, Ga, Mo, W, Si, Nb, Co, and Fe in an Ar atmosphere Then, it was injected into a mold to produce 4 types of ingots. These ingots are loaded into a quartz nozzle together with a predetermined amount of B, melted by high-frequency induction heating in an argon gas atmosphere, and then the molten metal is ejected onto a single copper roll having a diameter of 300 mm rotating at a peripheral speed of 40 m / s. Thus, an alloy ribbon was produced. The temperature at which each molten metal was ejected was 1320 ° C. As a result of ICP composition analysis, each alloy ribbon contains 1.1 atomic%, 1.6 atomic%, 0.5 atomic%, and 1.7 atomic% of B, respectively._7.9Zr_2.2Ni_3.3Ga_1.1Co_22.0B_1.1Fe_bal.(Example 12), Sm_6.5Nd_1.1Zr_2.6Mo_2.2Cr_1.1Si_1.1Co_25.0B_1.6Fe_bal.(Example 13), Sm_7.4Pr_1.1Zr_1.6Hf_0.5W_0.5Al_0.2C_2.2Co_33.9B_0.5Fe_bal.(Example 14), Sm_7.2Nd_0.6Dy_2.2Zr_2.7Mn_1.1Nb_1.1Co_26.0B_1.7Fe_bal.It had the composition of (Example 15). The coercive force of each obtained alloy ribbon was measured using a vibration test type magnetometer (VSM). As a result, the coercive forces of the alloy ribbons of Examples 12 to 15 were 20 kA / m, 33 kA / m, 29 kA / m, and 22 kA / m, respectively.
[0092]
Next, each alloy ribbon was heat-treated at 700 ° C. for 30 minutes in an inert atmosphere (Ar; 0.9 atm). Subsequently, these alloy ribbons were each pulverized by a ball mill to an average particle size of about 20 μm. Subsequently, the alloy powders of Examples 12, 13, and 14 were each subjected to heat treatment (nitriding treatment) at 450 ° C. for 50 hours in a nitrogen gas atmosphere of 1 atm. Was synthesized. The alloy powder of Example 15 was heat-treated at 350 ° C. for 10 hours in an atmosphere of 0.02 atm ammonia gas and 1 atm nitrogen gas to synthesize magnetic material powder having the composition shown in Table 2 below. .
[0093]
The magnetic material powders are all TbCu as a result of X-ray diffraction.₇It was confirmed that the phase was the main phase, and the lattice constant ratio c / a was found to be in the range of 0.854 to 0.876.
[0094]
About each said magnetic material powder, the magnetic characteristic (residual magnetic flux density, maximum energy product) was investigated using the vibration test type magnetometer (VSM). In addition, these magnetic characteristics have a density of the magnetic material powder of 7.74 g / cm.^ThreeTable 2 below shows the results calculated and corrected as the demagnetizing factor 0.15.
[0095]
[Table 2]

[0096]
As apparent from Table 2, Examples 11-1 and 11- obtained by nitriding using an alloy ribbon (12 kA / m, 36 kA / m) having a coercive force immediately after quenching of 56 kA / m or less. The magnetic material powder of Example 2-3 obtained by nitriding using an alloy ribbon (68 kA / m) whose coercive force immediately after quenching exceeds 56 kA / m in the magnetic material powder 2 was obtained. It can be seen that it is larger than the material powder.
[0097]
Moreover, it turns out that all the magnetic material powders of Examples 12 to 15 obtained by nitriding using an alloy ribbon having a coercive force of 56 kA / m or less immediately after quenching have excellent magnetic properties.
[0098]
In the production of the alloy ribbons of Examples 11-1 to 11-3, the ratio of the coercive force exceeding 56 kA / m was slightly less than 30%. The rate of the coercive force exceeding 56 kA / m can be reduced to less than 5% by setting the speed) to 42 m / sec, and the heat treatment, pulverization, and nitriding treatment are carried out as they are without particularly separating the obtained alloy ribbon. Etc., magnetic material powder having the same characteristics as those of Examples 11-1 and 11-2 can be obtained.
[0099]
(Examples 16-1 and 16-2)
First, high purity Sm, Zr, Co, and Fe raw materials were arc-melted in an Ar atmosphere to prepare an ingot. The composition of the ingot was Sm 7.5 atomic%, Zr 2.5 atomic%, Co 27 atomic%, and the balance was Fe. This ingot is loaded into a quartz nozzle together with a predetermined amount of B, melted by high-frequency induction heating in an argon gas atmosphere, and then the molten metal is ejected onto a single 300 mm diameter copper roll rotating at a peripheral speed of 40 m / s. An alloy ribbon was prepared. The temperature at the time of ejection was 1350 ° C. As a result of composition analysis by ICP, the alloy ribbon contains 1.9 atomic% of B, and Sm_7.4Zr_2.4Co_29.8B_1.9Fe_balIt had the composition of this. The thickness of the obtained plurality of alloy ribbons was measured using calipers. As a result, the thickness of each alloy ribbon was 5 to 45 μm.
[0100]
Next, an alloy ribbon having a thickness of 30 μm or less and an alloy ribbon having a thickness exceeding 30 μm are respectively selected, and these alloy ribbons are each heat-treated at 700 ° C. for 30 minutes in an inert atmosphere (Ar; 0.9 atm). Was given. Subsequently, these alloy ribbons were each pulverized by a ball mill to an average particle size of about 20 μm and then subjected to heat treatment (nitriding treatment) at 430 ° C. for 100 hours in a nitrogen gas atmosphere of 1 atm. Two kinds of magnetic material powders having compositions were synthesized.
[0101]
The magnetic material powders are all TbCu as a result of X-ray diffraction.₇It was confirmed that the phase was the main phase, and the lattice constant ratio c / a was found to be in the range of 0.854 to 0.876.
[0102]
About each said magnetic material powder, the magnetic characteristic (residual magnetic flux density, maximum energy product) was investigated using the vibration test type magnetometer (VSM). In addition, these magnetic characteristics have a density of the magnetic material powder of 7.74 g / cm.^ThreeTable 3 below shows the results of the calculation and correction with a demagnetizing factor of 0.15.
[0103]
(Examples 17 to 20)
First, after arc melting each raw material of high purity Sm, Nb, Pr, Dy, Zr, Hf, Mn, Ni, Cr, Al, Ga, Mo, W, Si, Nb, Co, and Fe in an Ar atmosphere Then, it was injected into a mold to produce 4 types of ingots. These ingots are loaded into a quartz nozzle together with a predetermined amount of B, melted by high-frequency induction heating in an argon gas atmosphere, and then the molten metal is ejected onto a single copper roll having a diameter of 300 mm rotating at a peripheral speed of 40 m / s. Thus, an alloy ribbon was produced. The temperature at which each molten metal was ejected was 1340 ° C. As a result of ICP composition analysis, each alloy ribbon contains 1.1 atomic%, 1.6 atomic%, 0.5 atomic%, and 1.7 atomic% of B, respectively._7.9Zr_2.2Ni_3.3Ga_1.1Co_22.0B_1.1Fe_bal.(Example 17), Sm_6.5Nd_1.1Zr_2.6Mo_2.2Cr_1.1Si_1.1Co_25.0B_1.6Fe_bal.(Example 18), Sm_7.4Pr_1.1Zr_1.6Hf_0.5W_0.5Al_0.2Co_33.9B_0.5C_2.2Fe_bal.(Example 19), Sm_7.2Nd_0.6Dy_2.2Zr_2.7Mn_1.1Nb_1.1Co_26.0B_1.7Fe_bal.It had the composition of (Example 20). The thickness of each alloy ribbon obtained was measured using calipers. As a result, the alloy ribbons had thicknesses shown in Table 3 below.
[0104]
Next, each alloy ribbon was heat-treated at 700 ° C. for 30 minutes in an inert atmosphere (Ar; 0.9 atm). Subsequently, these alloy ribbons were each pulverized by a ball mill to an average particle size of about 20 μm. Subsequently, the alloy powders of Examples 17, 18, and 19 were each subjected to heat treatment (nitriding treatment) at 430 ° C. for 100 hours in a nitrogen gas atmosphere of 1 atm. Was synthesized. Further, the alloy powder of Example 20 was heat-treated at 350 ° C. for 10 hours in an atmosphere of 0.02 atmospheres of ammonia gas and 1 atmosphere of nitrogen gas to synthesize magnetic material powders having the compositions shown in Table 3 below. .
[0105]
The magnetic material powders are all TbCu as a result of X-ray diffraction.₇It was confirmed that the phase was the main phase, and the lattice constant ratio c / a was found to be in the range of 0.854 to 0.876.
[0106]
About each said magnetic material powder, the magnetic characteristic (residual magnetic flux density, maximum energy product) was investigated using the vibration test type magnetometer (VSM). In addition, these magnetic characteristics have a density of the magnetic material powder of 7.74 g / cm.^ThreeTable 3 below shows the results of the calculation and correction with a demagnetizing factor of 0.15.
[0107]
[Table 3]

[0108]
As apparent from Table 3, the magnetic material powder of Example 16-1 obtained by nitriding using an alloy ribbon (thickness 15 to 20 μm) having a thickness of 30 μm or less immediately after quenching is a maximum. It can be seen that the energy product is larger than the magnetic material powder of Example 16-2 obtained by nitriding using an alloy ribbon (thickness: 32 to 36 μm) whose thickness immediately after quenching exceeds 30 μm.
[0109]
Moreover, it turns out that all the magnetic material powders of Examples 17 to 20 obtained by nitriding using an alloy ribbon having a thickness of 30 μm or less immediately after quenching are excellent in magnetic properties.
[0110]
(Examples 21 to 30)
First, high purity Sm, Zr, Co, B, and Fe raw materials were arc melted in an Ar atmosphere to prepare an ingot. The composition of the ingot was Sm 7.7 atomic%, Zr 2.5 atomic%, Co 27 atomic%, B 2.2 atomic%, and the balance was Fe. This ingot is loaded into a quartz nozzle, melted by high frequency induction heating in an argon gas atmosphere, and then the molten metal is spouted onto a single copper roll having a diameter of 300 mm rotating at a peripheral speed of 45 m / s to form an alloy ribbon. Produced. The temperature at the time of ejection was set to 1360 ° C.
[0111]
Next, the alloy ribbon was vacuum-sealed in a quartz tube and heat treated at 700 ° C. for 20 minutes. The heat-treated alloy ribbon was pulverized to an average particle size of 30 μm or less using a ball mill. The alloy powder was subjected to X-ray diffraction. As a result, TbCu₇It was confirmed that the phase was the main phase. From the result of X-ray diffraction, TbCu₇The lattice constants of the phases could be evaluated as a = 0.486 nm and c = 0.419 nm, and the lattice constant ratio c / a was found to be 0.862.
[0112]
Next, 10 kinds of magnetic material powders were synthesized by nitriding the alloy powders under the conditions shown in Table 4 below.
[0113]
About each said magnetic material powder, the maximum energy product was investigated using the ratio of the alpha-Fe phase, and the vibration test type | mold magnetometer (VSM). The ratio of the α-Fe phase is the main reflection intensity of the α-Fe phase (I_Fe) And TbCu₇Main reflection intensity of phase (I_Tb) Was substituted into the following formula and evaluated by the main reflection intensity ratio (I) calculated.
[0114]
I (%) = [I_Fe/ (I_Fe+ I_Tb] X 100
The maximum energy product is the density of the magnetic material powder of 7.74 g / cm.^ThreeAnd corrected as a demagnetizing factor of 0.15. These results are shown in Table 4 below.
[0115]
[Table 4]

[0116]
As apparent from Table 4, when the nitrogen pressure during nitriding is p (atmospheric pressure) and the nitriding temperature is T (° C.), p is 2 atmospheres or more and 2p + 400 ≦ T ≦ 2p + 420 The magnetic material powders of Examples 21 to 28 obtained by performing nitriding treatment in Example 2 are higher than the magnetic material powders of Examples 29 and 30 obtained by performing nitriding treatment in which the maximum energy product deviates from the above conditions. It can be seen that the magnetic properties are further improved.
[0117]
(Examples 31-1, 31-2)
First, high purity Sm, Zr, Co, B, and Fe raw materials were arc melted in an Ar atmosphere to prepare an ingot. The composition of the ingot was Sm 7.7 atomic%, Zr 2.5 atomic%, Co 27 atomic%, B 2.2 atomic%, and the balance was Fe. This ingot is loaded into a quartz nozzle, melted by high frequency induction heating in an argon gas atmosphere, and then the molten metal is spouted onto a single copper roll having a diameter of 300 mm rotating at a peripheral speed of 45 m / s to form an alloy ribbon. Produced. The temperature at the time of ejection was 1300 ° C.
[0118]
Next, the alloy ribbon was vacuum-sealed in a quartz tube and heat treated at 700 ° C. for 20 minutes. Subsequently, the heat-treated alloy ribbon was pulverized and classified using a ball mill, whereby an alloy powder having a particle size distribution shown in the following Table 5 (Example 31-1) and an alloy powder having a particle size of 22 μm or less (Example 31). -2) was obtained. As shown in Table 5 below, it was confirmed that the volume ratio of the fine powder having a particle size of 2.8 μm or less was 0.93% in the alloy powder of Example 31-1.
[0119]
[Table 5]

[0120]
Next, each of the alloy powders was subjected to heat treatment (nitriding treatment) at 440 ° C. for 65 hours in a nitrogen gas atmosphere of 10 atm to synthesize two magnetic material powders having the compositions shown in Table 6 below. Each magnetic material powder obtained was subjected to X-ray diffraction. As a result, all the diffraction peaks other than the diffraction peak of α-Fe are TbCu.₇It was confirmed that it was indexed by the type crystal structure. From the result of X-ray diffraction, TbCu₇The lattice constants of the phases could be evaluated as a = 0.4930 nm and c = 0.4252 nm, and the lattice constant ratio c / a was found to be 0.8625. Further, particle size distribution measurement was performed on each of the magnetic material powders. As a result, the magnetic material powder of Example 31-1 contained 1.08% by volume of the fine powder having a particle size of 2.8 μm or less, and the fine powder having the same particle size as that of the magnetic material powder of Example 31-2. Was 5.35% by volume.
[0121]
Next, 2 wt% of epoxy resin was added to each magnetic material powder and mixed, and then 8000 kg / cm.²The two types of bonded magnets were manufactured by compression molding at a pressure of 150 ° C. and then curing at a temperature of 150 ° C. for 2.5 hours.
[0122]
The magnetic properties (residual magnetic flux density, coercive force and maximum energy product) at room temperature of each of the obtained bonded magnets were measured. The results are also shown in Table 6 below.
[0123]
(Examples 32-36)
First, high-purity Sm, Nb, Pr, Er, Zr, Hf, Ni, V, Ga, Mo, W, Si, B, Co, and Fe powders are arc-melted in an Ar atmosphere and then injected into a mold. Thus, five types of ingots were produced. These ingots were loaded into a quartz nozzle, melted by high frequency induction heating in an argon gas atmosphere, and then the molten metal was ejected onto a single copper roll rotating at a peripheral speed of 45 m / s to produce an alloy ribbon. . The temperature at which each molten metal was ejected was 1310 ° C. As a result of the composition analysis by ICP, each alloy ribbon is Sm_6.3Nd_2.2Zr_2.2Mo_2.2Si_1.1Co_22.8B_0.9Fe_bal.(Example 32), Sm_7.2Pr_1.1Zr_2.2V_2.2W_1.1Ni_3.2Co_17.2B_0.9Fe_bal.(Example 33), Sm_8.2Er_1.1Zr_1.1Hf_1.1Mo_2.2Ga_1.1Co_20.7B_0.9Fe_bal.(Example 34), Sm_6.6Nd_2.2Zr_2.2Co_15.2B_1.4C_1.1Fe_bal.(Example 35), Sm_7.6Nd_1.1Zr_2.2Co_15.1B_1.9Fe_bal.It had the composition of (Example 36).
[0124]
Next, each alloy ribbon was vacuum-sealed in a quartz tube and heat-treated at 700 ° C. for 20 minutes. Subsequently, these heat-treated alloy ribbons were pulverized using a ball mill to obtain alloy powder.
[0125]
Next, each of the alloy powders was subjected to heat treatment (nitriding treatment) at 440 ° C. for 65 hours in a nitrogen gas atmosphere of 10 atm to synthesize five magnetic material powders having the compositions shown in Table 6 below. Each magnetic material powder obtained was subjected to X-ray diffraction. As a result, all the diffraction peaks other than the diffraction peak of α-Fe are TbCu.₇It was confirmed that it was indexed by the type crystal structure. Further, from the result of X-ray diffraction, it was found that the lattice constant ratio c / a was 0.852 to 0.873. Further, particle size distribution measurement was performed on each of the magnetic material powders. As a result, in the magnetic material powders of Examples 32-36, the content of fine powder having a particle size of 2.8 μm or less is 1.01%, 1.23%, 2.06%, 0.98% in volume ratio, respectively. 0.92%.
[0126]
Next, 2 wt% of epoxy resin was added to each magnetic material powder and mixed, and then 8000 kg / cm.²Five types of bonded magnets were manufactured by performing compression molding at a pressure of 150 ° C. and performing a curing treatment at a temperature of 150 ° C. for 2.5 hours.
[0127]
The magnetic properties (residual magnetic flux density, coercive force and maximum energy product) at room temperature of each of the obtained bonded magnets were measured. The results are also shown in Table 6 below.
[0128]
[Table 6]

[0129]
As can be seen from Table 6, the bonded magnet of Example 31-1 obtained using a magnetic material powder having a fine powder particle size of 2.8 μm or less in a content of 5% by volume or less had a residual magnetic flux density at room temperature. The coercive force and the maximum energy product are both superior to the bonded magnet of Example 31-2 obtained using a magnetic material powder in which the content of fine powder having the same particle size exceeds 5% by volume. Recognize.
[0130]
In addition, the bonded magnets of Examples 32-36 obtained using a magnetic material powder having a fine powder having a particle size of 2.8 μm or less in a content of 5% by volume or less have a residual magnetic flux density, a coercive force, and a maximum energy at room temperature. It can be seen that the product is excellent.
[0131]
(Examples 37-1 to 37-5)
First, high purity Sm, Zr, Co, and Fe raw materials were arc-melted in an Ar atmosphere to prepare an ingot. The composition of the ingot was Sm 7.5 atomic%, Zr 2.5 atomic%, Co 27 atomic%, and the balance was Fe. This ingot is loaded into a quartz nozzle together with B, melted by high frequency induction heating in an argon gas atmosphere, and then the molten metal is ejected onto a single copper roll rotating at a peripheral speed of 42 m / s to produce an alloy ribbon. did. The temperature at the time of ejection was 1350 ° C. As a result of compositional decomposition by ICP, it was found that 2.16 atomic% of B was contained in the alloy ribbon.
[0132]
Next, the alloy ribbon was vacuum-sealed in a quartz tube and heat-treated at 720 ° C. for 15 minutes. The alloy ribbon after the heat treatment was pulverized to a particle size of 30 μm or less using a mortar, and then subjected to a heat treatment (nitriding treatment) at 450 ° C. for 80 hours in a nitrogen atmosphere of 10 atm to synthesize a magnetic material powder. The composition of this magnetic material powder is Sm_6.88Zr_2.29Co_24.77B_1.97N_9.00Fe_balMet.
[0133]
According to the result of X-ray diffraction, the magnetic material powder has all diffraction peaks other than the minute α-Fe diffraction peak, which is hexagonal TbCu.₇Indexed by the type crystal structure, TbCu₇It was confirmed that the phase was the main phase. From the result of X-ray diffraction, TbCu₇The lattice constant of the phase could be evaluated as a = 0.4925 nm and c = 0.4258 nm, and the lattice constant ratio c / a was found to be 0.8646.
[0134]
Next, the TbCu₇R consisting of only a particle size of 50 μm or more by sieving with the magnetic material powder of the mold₂Fe₁₄Five types of mixed magnetic material powders prepared by mixing B-type magnetic material powder (trade name manufactured by GM; MQP-B powder) in the proportions shown in Table 7 below, and epoxy resin were respectively added to these mixed magnetic material powders. After adding 2% by weight and mixing, 8000 kg / cm²Five types of bonded magnets were manufactured by performing compression molding at a pressure of 150 ° C. and performing a curing treatment at a temperature of 150 ° C. for 2.5 hours.
[0135]
The bulk density and magnetic properties (residual magnetic flux density, coercive force and maximum energy product) of each of the obtained bonded magnets were measured. The results are also shown in Table 7 below. In Table 7 below, the TbCu₇Magnet (Example 37-6) manufactured using only the magnetic material powder of the mold and R₂Fe₁₄The bulk density and magnetic properties at room temperature of a bonded magnet (Comparative Example 3) manufactured using only the B-based magnetic material powder will be described.
[0136]
[Table 7]

[0137]
As apparent from Table 7, TbCu₇Type magnetic material powder and R₂Fe₁₄The bonded magnets of Examples 37-1 to 37-5 manufactured using mixed magnetic material powder made of B-based magnetic material powder were TbCu₇It can be seen that the packing density was improved as compared with the bonded magnet of Example 37-6 manufactured using the magnetic material powder of the mold, and the performance of the magnet was improved.
[0138]
R₂Fe₁₄The bonded magnet of Comparative Example 3 manufactured using only the B-based magnetic material powder is easily corroded, and the deterioration of the magnetic characteristics accompanying this is remarkable.
[0139]
In contrast, TbCu₇Type magnetic material powder and R₂Fe₁₄The bonds of Examples 37-1 to 37-5 manufactured using the mixed magnetic material powder made of the B-based magnetic material powder have improved corrosion resistance. For example, the change in magnetic properties after a 50 h corrosion resistance test in a constant temperature and humidity chamber having a humidity of 90% and a temperature of 80 ° C. was examined. TbCu₇A horn magnet containing 50 vol% or more of a magnetic material powder of the mold showed no corrosion and showed excellent corrosion resistance. R₂Fe₁₄As the ratio of the B-based magnetic material powder increases, the generation of rust becomes more prominent, and the deterioration of the magnetic characteristics becomes significant.
[0140]
Table 8 below shows the results of the corrosion resistance tests of Examples 37-1 to 37-3 and Comparative Example 3 in Table 7.
[0141]
[Table 8]

[0142]
[0143]
【The invention's effect】
As described above, according to the present invention, a magnetic material having a high residual magnetic flux density can be provided. Moreover, by using such a magnetic material, it becomes possible to manufacture a permanent magnet such as a bonded magnet having excellent magnetic properties.
[Brief description of the drawings]
FIG. 1 is a characteristic diagram showing the relationship between nitrogen pressure and nitrogen absorption start temperature when nitriding an alloy powder used in the present invention.
2 is a characteristic diagram showing an X-ray diffraction pattern of the magnetic material powder of Example 2. FIG.

Claims (9)

General formula R1 _x R2 _y B _z M _100-xyz
However, R1 is at least one kind of rare earth element (including Y), and 50 atom% or more is Sm, R2 is at least one element selected from Zr and Hf, M is Fe alone or Fe is 50 atom% or more The elements consisting of Fe and Co, x, y, and z are represented by atomic percentages of 2 ≦ x, 4 ≦ x + y ≦ 20, and 0.001 ≦ z ≦ 10, respectively, and the main phase is a TbCu ₇ type crystal structure A magnetic material characterized by comprising: 2. The magnetic material according to claim 1, wherein c / a which is a ratio of lattice constants a and c of the TbCu ₇ type crystal structure is 0.847 or more.   The magnetic material according to claim 1, wherein z in the general formula is 0.1 ≦ z ≦ 3. 4. The magnetic material according to claim 1, wherein y in the general formula is 0.1 ≦ y ≦ 10. 5. General formula
R1 _x R2 _y B _z M _100-x-y-z
However, R1 is at least one element selected from rare earth elements including Y, and 50 atom% or more is Sm, R2 is at least one element selected from Zr and Hf, M is Fe alone or Fe is 50 atom% The elements consisting of Fe and Co, x, y, and z are represented by atomic percentages of x ≧ 2, 4 ≦ x + y ≦ 20, and 0.001 ≦ z ≦ 10, respectively, and the main phase is TbCu ₇ A magnetic material powder having a type crystal structure;
With binder
Bond magnet characterized by including. The bonded magnet according to claim 5, wherein the binder is made of a synthetic resin. 7. The bonded magnet according to claim 5, wherein the magnetic material powder has a content ratio of a powder having a particle size of 2.8 μm or less of 5% by volume or less . R ₂ Fe ₁₄ The bond according to any one of claims 5 to 7, further comprising a magnetic material powder containing a B phase (wherein R represents at least one element selected from rare earth elements including Y) as a main phase. magnet. The mixing ratio before following general formula _{R1 x R2 y B z M 100} -xyz of the magnetic material powder (A) and the magnetic material powder as the main phase of R ₂ Fe ₁₄ B phase (B) is a weight ratio A / B is 0.1-10, The bonded magnet of Claim 8 characterized by the above-mentioned.

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