JP3771224B2 - Amorphous soft magnetic alloy powder and powder core and radio wave absorber using the same - Google Patents

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【０１１４】
【表２】

【０１１５】
表１、表２に示す結果からＮｏ．１〜２の軟磁性合金粉末は不定形のものが得られており、アスペクト比の平均、Ｄ_５０、比表面積、酸素濃度が大きく、また、タップ密度が小さいことがわかる。このようなＮｏ．１〜２の軟磁性合金粉末を用いて作製した圧粉コアはコアロスが大きく、直流重畳特性が低いことがわかる。Ｎｏ．１〜２の軟磁性合金粉末は酸素濃度が大きいので、熱的安定性が変化すると考えられる。
これに対してＮｏ．３の軟磁性合金粉末は、略球形のものが得られており、比表面積、酸素濃度が小さく、また、タップ密度が大きく、また、Ｎｏ．１〜２のものに比べて飽和磁化σsも高いことがわかる。このＮｏ．３の軟磁性合金粉末を用いて作製した圧粉コアは、Ｎｏ．１〜２の軟磁性合金粉末を用いて作製した圧粉コアに比べて大幅にコアロスを低くでき、また、直流重畳特性については向上していることがわかる。
なお、実験例１においてＦｅ_７５Ｃｒ_２Ｐ_１３Ｃ_５Ｂ_５なる組成の軟磁性合金粉末の平均粒径（Ｄ_５０）が９．０μｍ以上になるようにした場合には、組織が結晶化することが分かった。
【０１１６】
（実験例２）
Ｆｅ、Ｆｅ-Ｃ合金、Ｆｅ-Ｐ合金、Ｃｒ、Ｂ又はＢとＳｉを原料としてそれぞれ所定量秤量し、大気雰囲気下においてこれらの原料を図１に示す高圧水噴霧装置の溶湯るつぼ内に入れて溶解し、溶湯るつぼの溶湯ノズルから合金溶湯を滴下するとともに、図１に示す水噴霧器の水噴射ノズルから高圧水を噴射して合金溶湯を霧状にし、チャンバ内で霧状の合金溶湯を急冷させて軟磁性合金粉末を作製する際、製造条件を変更して各種の軟磁性合金粉末（Ｎｏ．４〜１４の軟磁性合金粉末）を作製した。
【０１１７】
得られた軟磁性合金粉末の組成は、Ｆｅ_{１００−ｔ−ｙ−ｚ−ｗ−ｘ}Ｐ_ｙＳｉ_ｔＣ_ｚＢ_ｗＣｒ_ｘなる組成(但し、ｚは１．２〜７原子％、ｗは５．６〜８．７原子％、ｘは１．９６原子％〜２原子％、ｙは８．４４〜１２．７４原子％、ｔは０〜４．８７原子％）であった。なお、前記組成式中のｖは、Ｐの組成比、又はＰとＳｉの合計の組成比を示すものである。
また、上記のＦｅ_{１００−ｔ−ｙ−ｚ−ｗ−ｘ}Ｐ_ｙＳｉ_ｔＣ_ｚＢ_ｗＣｒ_ｘなる組成の各種の軟磁性合金粉末についてＸ線回折法により組織構造の解析を行ったところ、いずれの合金粉末もＸ線回折パターンはブロードなパターンを示しており、非晶質相からなる組織から構成されていることが分かった。従って、Ｆｅ、Ｃｒ、Ｐ、Ｃ、Ｂ又はＢ及びＳｉからなる合金であっても、非晶質相からなる非晶質軟磁性合金粉末を形成できることがわかる。
また、上記のＦｅ_{１００−ｙ（−ｔ）−ｚ−ｗ−ｘ}(Ｐ_ｙ又はＰ_ｙＳｉ_ｔ）Ｃ_ｚＢ_ｗＣｒ_ｘなる組成の各種の軟磁性合金粉末を走査型電子顕微鏡(ＳＥＭ)により観察し、形状を調べた。その結果を表３に示す。
得られた軟磁性合金粉末の平均粒径（Ｄ_５０）、タップ密度、比表面積、酸素濃度、アスペクト比の最小値と最大値と平均値を調べた結果を表３に示す。
【０１１８】
更に、得られた各種の軟磁性合金粉末のＤＳＣ測定(Differential scanning caloriemetry：示差走査熱量測定)を行い、ガラス遷移温度Ｔg、結晶化開始温度Ｔx、キュリー温度Ｔc及び融点Ｔmを測定するとともに、過冷却液体の温度間隔ΔＴx及びＴg／Ｔmを求めたを測定した。これらの結果を表４に示す。尚、ＤＳＣ測定の際の昇温速度は０．６７Ｋ／秒であった。なお、表４中のＴm*は合金の融解温度を示す。
また、得られた各種の軟磁性合金粉末について、実験例１と同様にして飽和磁化σsを測定した。これらの結果を表４に合わせて示す。
【０１１９】
次に、この実験例２で得られた軟磁性合金粉末を用いる以外は上記実験例１と同様にして造粒粉末を作製し、さらにこれら造粒粉末を用いて上記実験例１と同様にして各種の圧粉コアを製造した。
得られた各種の圧粉コアのコアロス（Ｗ）を実験例１と同様にして測定した。その結果を表４に合わせて示す。
また、得られた各種の圧粉コアの実効透磁率（μ’）と直流重畳特性（μ’_{ＤＣ５５００} ）を実験例１と同様にして測定した。その結果を表４に合わせて示す。
【０１２０】
【表３】

【０１２１】
【表４】

【０１２２】
表３、表４に示す結果からＮｏ．４〜１２の軟磁性合金粉末は、略球状のものが得られていることがわかる。
Ｎｏ．４と９の軟磁性合金粉末はＰとＳｉの合計の組成比ｖが１５原子％を越えており、ΔＴxが４６Ｋ以下であることがわかる。
これに対してＰの組成比又はＰとＳｉの合計の組成比ｖが１５原子％以下のＮｏ．５〜８の軟磁性合金粉末においては、ＰとＳｉの両方が添加されている場合の方がＰの単独添加に比べてΔＴxを大きくでき、ＰとＳｉの両方を添加する場合は、組成比ｖが大きいほどΔＴxを大きくでき、非晶質相形成能を向上できることがわかる。なお、実験例２においてＦｅ_{７０．８５}Ｃｒ_２Ｐ_{１２．２９}Ｃ_４．６５Ｂ_７Ｓｉ_３．３２なる組成の軟磁性合金粉末の平均粒径（Ｄ_５０）が９．０μｍ以上になるようにした場合には、組織が結晶化することが分かった。
【０１２３】
また、Ｎｏ．１０〜１２の軟磁性合金粉末においては、Ｓｉの添加量の増加に従ってΔＴxを大きくでき、非晶質相形成能を向上できることがわかる。
次に、Ｎｏ．１３の軟磁性合金粉末は不定形のものが得られており、アスペクト比の平均、Ｄ_５０、比表面積、酸素濃度が大きく、また、タップ密度が小さいことがわかる。このようなＮｏ．１３の軟磁性合金粉末を用いて作製した圧粉コアはコアロスが大きく、直流重畳特性が悪いことがわかる。Ｎｏ．１３の軟磁性合金粉末は酸素濃度が大きいので、熱的安定性が変化すると考えられる。
これに対してＮｏ．１４の軟磁性合金粉末は、略球形のものが得られており、比表面積、酸素濃度が小さく、また、タップ密度が大きく、また、Ｎｏ．１３のものに比べて飽和磁化σsも高いことがわかる。このＮｏ．１４の軟磁性合金粉末を用いて作製した圧粉コアは、Ｎｏ．１３の軟磁性合金粉末を用いて作製した圧粉コアに比べて大幅にコアロスを低くでき、直流重畳特性が優れることがわかる。
【０１２４】
（実験例３）
Ｆｅ、Ｆｅ-Ｃ合金、Ｆｅ-Ｐ合金、Ｂ、Ｓｉ、Ｃｒを原料としてそれぞれ所定量秤量し、大気雰囲気下においてこれらの原料を図１に示す高圧水噴霧装置の溶湯るつぼ内に入れて溶解し、溶湯るつぼの溶湯ノズルから合金溶湯を滴下するとともに、図１に示す水噴霧器の水噴射ノズルから高圧水を噴射して合金溶湯を霧状にし、チャンバ内で霧状の合金溶湯を急冷させて軟磁性合金粉末を作製する際、製造条件を変更して各種の軟磁性合金粉末（Ｎｏ．１５〜２１の軟磁性合金粉末）を作製した。なお、Ｎｏ．１７の軟磁性合金粉末については、粉末形成後室温で長時間放置した。
【０１２５】
得られた軟磁性合金粉末の組成は、Ｆｅ_７８Ｐ_９．２３Ｃ_２．２Ｂ_７．７Ｓｉ_２．８７又はＦｅ_{１００−ｔ−ｙ−ｚ−ｗ−ｘ}Ｐ_ｙＳｉ_ｔＣ_ｚＢ_ｗＣｒ_ｘなる組成(但し、ｚは２．１６〜２．２原子％、ｗは７．５４〜７．７原子％、ｘは１原子％〜８原子％、ｙは９．０４〜９．２３原子％、ｔは２．８７〜４．８７原子％、ｖは１２．１〜１３．９１原子％）であった。なお、前記組成式中のｖはＰとＳｉの合計の組成比を示すものである。
また、上記のＦｅ_７８Ｐ_９．２３Ｃ_２．２Ｂ_７．７Ｓｉ_２．８７又はＦｅ_{１００−ｔ−ｙ−ｚ−ｗ−ｘ}Ｐ_ｙＳｉ_ｔＣ_ｚＢ_ｗＣｒ_ｘなる組成の各種の軟磁性合金粉末についてＸ線回折法により組織構造の解析を行ったところ、いずれの合金粉末もＸ線回折パターンはブロードなパターンを示しており、非晶質相からなる組織から構成されていることが分かった。従って、Ｆｅ、Ｃｒ又はＡｌ、Ｐ、Ｃ、Ｂ、Ｓｉからなる合金であっても、非晶質相からなる非晶質軟磁性合金粉末を形成できることがわかる。
また、Ｆｅ_７８Ｐ_９．２３Ｃ_２．２Ｂ_７．７Ｓｉ_２．８７又はＦｅ_{１００−ｔ−ｙ−ｚ−ｗ−ｘ}Ｐ_ｙＳｉ_ｔＣ_ｚＢ_ｗＣｒ_ｘなる組成の各種の軟磁性合金粉末を走査型電子顕微鏡(ＳＥＭ)により観察し、形状を調べた。その結果を表５に示す。
得られた軟磁性合金粉末の平均粒径（Ｄ_５０）、タップ密度、比表面積、酸素濃度、アスペクト比の最小値と最大値と平均値を調べた結果を表５に示す。
【０１２６】
更に、得られた各種の軟磁性合金粉末のＤＳＣ測定(Differential scanning caloriemetry：示差走査熱量測定)を行い、ガラス遷移温度Ｔg、結晶化開始温度Ｔx、キュリー温度Ｔc及び融点Ｔmを測定するとともに、過冷却液体の温度間隔ΔＴx及びＴg／Ｔmを求めたを測定した。これらの結果を表６に示す。尚、ＤＳＣ測定の際の昇温速度は０．６７Ｋ／秒であった。なお、表６中のＴm*は合金の融解温度を示す。
また、得られた各種の軟磁性合金粉末について、実験例１と同様にして飽和磁化σsを測定した。これらの結果を表６に合わせて示す。
【０１２７】
次に、この実験例３で得られた軟磁性合金粉末を用いる以外は上記実験例１と同様にして造粒粉末を作製し、さらにこれら造粒粉末を用いて上記実験例１と同様にして各種の圧粉コアを製造した。
得られた各種の圧粉コアのコアロス（Ｗ）を実験例１と同様にして測定した。その結果を表６に合わせて示す。
また、得られた各種の圧粉コアの実効透磁率（μ’）と直流重畳特性（μ’_{ＤＣ５５００} ）を実験例１と同様にして測定した。その結果を表６に合わせて示す。
【０１２８】
【表５】

【０１２９】
【表６】

【０１３０】
表５と表６に示した結果からＮｏ．１５〜２１の軟磁性合金粉末は、略球状のものが得られていることがわかる。
しかしながらＮｏ．１５の軟磁性合金粉末は酸素濃度が大きく、錆が発生しており、耐腐食性が悪いことがわかる。Ｎｏ．１７の軟磁性合金粉末は酸素濃度が大きく、平均粒径（Ｄ_５０）が小さく、この合金粉末を用いて作製した圧粉コアはコアロスが大きいことがわかる。
また、Ｃｒの添加量が１〜４原子％のＮｏ．１６、１８〜２０の軟磁性合金粉末は、Ｃｒの添加量が８原子％のＮｏ．２１の軟磁性合金粉末に比べて飽和磁化が大きいことがわかる。Ｎｏ．２１の軟磁性合金粉末の飽和磁化が低下したのは、Ｃｒの添加量の増加に伴ってＦｅ濃度が相対的に低下したからである。
また、Ｃｒの添加量が１〜４原子％のＮｏ．１６、１８〜２０の軟磁性合金粉末においては、Ｃｒの添加量の増加に伴ってΔＴxが大きくなり、非晶質形成能が向上していることがわかる。
【０１３１】
（実験例４）
Ｆｅ、Ｆｅ-Ｃ合金、Ｆｅ-Ｐ合金、Ｂ、Ｓｉ及びＣｒを原料としてそれぞれ所定量秤量し、大気雰囲気下においてこれらの原料を図１に示す高圧水噴霧装置の溶湯るつぼ内に入れて溶解し、溶湯るつぼの溶湯ノズルから合金溶湯を滴下するとともに、図１に示す水噴霧器の水噴射ノズルから高圧水を噴射して合金溶湯を霧状にし、チャンバ内で霧状の合金溶湯を急冷させて軟磁性合金粉末を作製する際、製造条件を変更して各種の軟磁性合金粉末（Ｎｏ．２２〜４８の軟磁性合金粉末）を作製した。
【０１３２】
得られた軟磁性合金粉末の組成は、Ｆｅ_{７４．４３}Ｃｒ_１．９６Ｐ_９．０４,Ｃ_２．１６Ｂ_７．５４Ｓｉ_４．８７なる組成であった。
また、上記のＦｅ_{７４．４３}Ｃｒ_１．９６Ｐ_９．０４Ｃ_２．１６Ｂ_７．５４Ｓｉ_４．８７なる組成の各種の軟磁性合金粉末についてＸ線回折法により組織構造の解析を行ったところ、いずれの合金粉末もＸ線回折パターンはブロードなパターンを示しており、非晶質相からなる組織から構成されていることが分かった。従って、Ｆｅ、Ｃｒ、Ｐ、Ｃ、Ｂ、Ｓｉからなる合金であっても、非晶質相からなる非晶質軟磁性合金粉末を形成できることがわかる。図８に、Ｎｏ．２３の軟磁性合金粉末の状態を制限視野電子線回折により分析した結果を示す。
また、Ｆｅ_{７４．４３}Ｃｒ_１．９６Ｐ_９．０４Ｃ_２．１６Ｂ_７．５４Ｓｉ_４．８７なる組成の各種の軟磁性合金粉末を走査型電子顕微鏡(ＳＥＭ)により観察し、形状を調べた。その結果を表７、表８に示す。また、図１０に、Ｎｏ．２３の軟磁性合金粉末をＳＥＭにより観察した結果を示す。また、図１２に、Ｎｏ．２３の軟磁性合金粉末の組織の状態を透過型電子顕微鏡（ＴＥＭ）により観察した結果を示す。
得られた軟磁性合金粉末の平均粒径（Ｄ_５０）、タップ密度、比表面積、酸素濃度、アスペクト比の最小値と最大値と平均値を調べた結果を表７、表８に示す。
【０１３３】
更に、得られた各種の軟磁性合金粉末のＤＳＣ測定(Differential scanning caloriemetry：示差走査熱量測定)を行い、ガラス遷移温度Ｔg、結晶化開始温度Ｔx、キュリー温度Ｔc及び融点Ｔmを測定するとともに、過冷却液体の温度間隔ΔＴx及びＴg／Ｔmを求めたを測定した。これらの結果を表９、表１０に示す。尚、ＤＳＣ測定の際の昇温速度は０．６７Ｋ／秒であった。なお、表９、表１０中のＴm*は合金の融解温度を示す。
また、得られた各種の軟磁性合金粉末について、実験例１と同様にして飽和磁化σsを測定した。これらの結果を表９、表１０に合わせて示す。
【０１３４】
次に、この実験例４で得られた軟磁性合金粉末を用いる以外は上記実験例１と同様にして造粒粉末を作製し、さらにこれら造粒粉末を用いて上記実験例１と同様にして各種の圧粉コアを製造した。
得られた各種の圧粉コアのコアロス（Ｗ）を実験例１と同様にして測定した。その結果を表９、表１０に合わせて示す。また、得られた各種の圧粉コアの実効透磁率（μ’）と直流重畳特性（μ’_{ＤＣ５５００} ）を実験例１と同様にして測定した。その結果を表９、表１０に合わせて示す。
【０１３５】
【表７】

【０１３６】
【表８】

【０１３７】
【表９】

【０１３８】
【表１０】

【０１３９】
表７〜表１０に示す結果からＮｏ．２２〜４８の軟磁性合金粉末は、略球状のものが得られていることがわかる。
しかしながらＮｏ．２２の軟磁性合金粉末は比表面積が０．３２ｍ^２／ｇと大きく、また、この軟磁性合金粉末を用いて作製した圧粉コアはコアロスが大きいことがわかる。また、Ｎｏ．２４の軟磁性合金粉末はタップ密度が３．６８Ｍｇ／ｍ^３と小さく、また、この軟磁性合金粉末を用いて作製した圧粉コアはコアロスが大きいことがわかる。
【０１４０】
これに対してＤ_５０が４μｍより大きく、かつ４５μｍ以下であり、タップ密度が３．７Ｍｇ／ｍ^３以上、比表面積が０．３ｍ^２／ｇ以下、酸素濃度が３０００ｐｐｍ以下とした軟磁性合金粉末（Ｎｏ．２５、２６、２７、３２、３５、３９、４０、４２、４４、４５、４６）を用いて作製した圧粉コアはコアロス（Ｗ）を４５０ｋＷ／ｍ^３以下にでき、また、実効透磁率μ’が５８〜７１であり、直流バ直流重畳特性μ’_{ＤＣ５５００}が３１．５〜３４．５とすることができる。
また、Ｄ_５０が４μｍより大きく、かつ１６μｍ以下であり、タップ密度が４．０Ｍｇ／ｍ^３以上、比表面積が０．２３ｍ^２／ｇ以下、酸素濃度が２０００ｐｐｍ以下とした軟磁性合金粉末（Ｎｏ．２３、２８、２９、３０、３１、３３、３４、３６、３７、３８、４１）を用いて作製した圧粉コアはコアロス（Ｗ）を２５０ｋＷ／ｍ^３以下にでき、また、実効透磁率μ’が６１〜７０であり、直流重畳特性μ’_{ＤＣ５５００}が３２〜３４とすることができる。
また、図１０のＳＥＭ写真からＮｏ．２３の軟磁性合金粉末は略球状であることがわかる。また、このＮｏ．２３の軟磁性合金粉末は、図８の回折スポットの分布形態から明らかなようにアモルファス特有のハローなパターンが見られ、非晶質相から構成されていることがわかる。また、図１２のＴＥＭの写真からＮｏ．２３の軟磁性合金粉末は、組織状態が均一であり、結晶相が混在していないことがわかる。
【０１４１】
（実験例５）
Ｆｅ、Ｆｅ-Ｃ合金、Ｆｅ-Ｐ合金、Ｂ、Ｓｉ、Ｃｒ及びＡｌ又はＭｏ又はＶを原料としてそれぞれ所定量秤量し、大気雰囲気下においてこれらの原料を図１に示す高圧水噴霧装置の溶湯るつぼ内に入れて溶解し、溶湯るつぼの溶湯ノズルから合金溶湯を滴下するとともに、図１に示す水噴霧器の水噴射ノズルから高圧水を噴射して合金溶湯を霧状にし、チャンバ内で霧状の合金溶湯を急冷させて軟磁性合金粉末を作製する際、製造条件を変更して各種の軟磁性合金粉末（Ｎｏ．５０〜５７の軟磁性合金粉末）を作製した。
【０１４２】
得られた軟磁性合金粉末の組成は、Ｆｅ_{１００−ｔ−ｙ−ｚ−ｗ−ｘ}Ｐ_ｙＳｉ_ｔＣ_ｚＢ_ｗＭ_ｘなる組成(但し、ｚは２．１６〜２．１８原子％、ｗは７．５４〜７．６２原子％、ｘは１原子％〜１．９６原子％、ｙは７〜９．１４原子％、ｔは３．８７〜１０原子％）であった。なお、前記組成式中のＭはＣｒ又はＭｏ又はＶを示す。
なお、Ｎｏ．５６の軟磁性合金粉末はＮｏ．２３のものと組成が同じであるが、平均粒径（Ｄ_５０）、タップ密度、比表面積、酸素濃度、アスペクト比の平均値が本発明の範囲外であり、Ｎｏ．５７の軟磁性合金粉末は、Ｎｏ．２３のものと組成が同じであるが、水アトマイズ法で製造する際の製造条件が異なるものであり、より具体的にはアトマイズ時の水圧を低下させることにより、溶湯の冷却速度も低下し、アモルファスと結晶の混相状態の粉末となるものである。
また、上記のＦｅ_{１００−ｔ−ｙ−ｚ−ｗ−ｘ}Ｐ_ｙＳｉ_ｔＣ_ｚＢ_ｗＭ_ｘなる組成の各種の軟磁性合金粉末についてＸ線回折法により組織構造の解析を行ったところ、Ｎｏ．５１、Ｎｏ．５３〜Ｎｏ．５６の合金粉末もＸ線回折パターンはブロードなパターンを示しており、非晶質相からなる組織から構成されており、Ｎｏ．５７の合金粉末のＸ線回折パターンは非ブロードなパターンを示していることが分かった。図９に、Ｎｏ．５７の軟磁性合金粉末の状態を制限視野電子線回折により分析した結果を示す。
従って、Ｆｅ、Ｃｒ、Ｐ、Ｃ、Ｂ、Ｓｉ、Ｍｏ又はＶからなる合金において、平均粒径（Ｄ_５０）、タップ密度、比表面積、酸素濃度、アスペクト比の平均値が本発明の範囲内とし、しかも水アトマイズ法で製造する際の製造条件をコントロールすることにより非晶質相からなる非晶質軟磁性合金粉末（Ｎｏ．５１、Ｎｏ．５３〜Ｎｏ．５６）を形成できることがわかる。
また、Ｆｅ_{１００−ｔ−ｙ−ｚ−ｗ−ｘ}Ｐ_ｙＳｉ_ｔＣ_ｚＢ_ｗＭ_ｘなる組成の各種の軟磁性合金粉末を走査型電子顕微鏡(ＳＥＭ)により観察し、形状を調べた。その結果を表１１に示す。図１１に、Ｎｏ．５６の軟磁性合金粉末をＳＥＭにより観察した結果を示す。図１３に、Ｎｏ．５７の軟磁性合金粉末をＴＥＭにより観察した結果を示す。 得られた軟磁性合金粉末の平均粒径（Ｄ_５０）、タップ密度、比表面積、酸素濃度、アスペクト比の最小値と最大値と平均値を調べた結果を表１２に示す。
【０１４３】
更に、得られた各種の軟磁性合金粉末のＤＳＣ測定(Differential scanning caloriemetry：示差走査熱量測定)を行い、ガラス遷移温度Ｔg、結晶化開始温度Ｔx、キュリー温度Ｔc及び融点Ｔmを測定するとともに、過冷却液体の温度間隔ΔＴx及びＴg／Ｔmを求めたを測定した。これらの結果を表１２に示す。尚、ＤＳＣ測定の際の昇温速度は０．６７Ｋ／秒であった。なお、表１２中のＴm*は合金の融解温度を示す。
また、得られた各種の軟磁性合金粉末について、実験例１と同様にして飽和磁化σsを測定した。これらの結果を表１２に合わせて示す。
【０１４４】
次に、この実験例５で得られた軟磁性合金粉末を用いる以外は上記実験例１と同様にして造粒粉末を作製し、さらにこれら造粒粉末を用いて上記実験例１と同様にして各種の圧粉コアを製造した。
得られた各種の圧粉コアのコアロス（Ｗ）を実験例１と同様にして測定した。その結果を表１２に合わせて示す。
また、得られた各種の圧粉コアの実効透磁率（μ’）と直流重畳特性（μ’_{ＤＣ５５００} ）を実験例１と同様にして測定した。その結果を表１２に合わせて示す。
【０１４５】
比較のために一般的に知られている従来の合金粉末としてＦｅ−Ｃｒ−Ｓｉ−Ｂなる組成（Ｆｅ_７３Ｃｒ_２Ｂ_１５Ｓｉ_１０なる組成）の合金粉末（Ｎｏ．５２）の組織構造、形状、平均粒径（Ｄ_５０）、タップ密度、比表面積、酸素濃度、アスペクト比の最小値と最大値と平均値についても実験例１と同様にして測定した。これらの結果を表１１に合わせて示す。このＮｏ．５２の合金粉末は、水アトマイズ法により作製したものである。このＮｏ．５２の合金粉末の組織構造は、アモルファス相と結晶相を有していることがわかった。
また、Ｎｏ．５２の合金粉末についても実験例１と同様にして飽和磁化σsを測定した。その結果を表１２に合わせて示す。また、Ｎｏ．５２の合金粉末を用いる以外は上記実験例１と同様にして造粒粉末を作製し、さらにこれら造粒粉末を用いて上記実験例１と同様にして圧粉コアを製造し、この圧粉コアのコアロス（Ｗ）と実効透磁率（μ’）と直流重畳特性（μ’_{ＤＣ５５００} ）を実験例１と同様にして測定した。その結果を表１２に合わせて示す。
【０１４６】
【表１１】

【０１４７】
【表１２】

【０１４８】
表１１、表１２に示す結果からＮｏ．５２の合金粉末は略球状であるが、その組織構造は非晶質相（アモルファス相）と結晶相からなり、また、このＮｏ．５２の合金粉末を用いて作製した圧粉コアのコアロスは１０００ｋＷ／ｃｍ^３以上と大きいものであった。
また、図１１のＳＥＭ写真からＮｏ．５６の軟磁性合金粉末は不定形であり、また、表１１〜表１２の結果からこのＮｏ．５６の軟磁性合金粉末を用いた圧粉コアはコアロスが大きく、直流重畳特性が悪いことわかる。
また、このＮｏ．５７の軟磁性合金粉末は、図９の回折スポットの分布形態から明らかなように結晶の組織に対応するような形で複数のスポットが見られ、非晶質相と結晶相から構成されていることがわかる。また、図１３のＴＥＭの写真からＮｏ．５７の軟磁性合金粉末は、組織状態が不均一であり、結晶相と非晶質相が混在していることがわかる。また、表１１〜表１２の結果からこのＮｏ．５７の軟磁性合金粉末を用いた圧粉コアはコアロスが大きいことわかる。
これに対してＮｏ．５１、５３、５４、５５の軟磁性合金粉末は、略球状であり、その組織構造は非晶質相（アモルファス相）からなるなることがわかる。
【０１４９】
（実験例６）
造粒粉末の粒径と流動性について調べた。
ここでの流動性は、直径２．５ｍｍの孔内に造粒粉末５０ｇを流し込む際、造粒粉末の粒径を変更し、孔内を通過する時間（秒）を測定した。ここで用いた造粒粉末は、実施形態の非晶質軟磁性合金粉末９８．３重量％に対し、絶縁材としてシリコーン樹脂を１．４重量％と、潤滑剤としてステアリン酸亜鉛を０．３重量％とを混合、造粒したものである。このようにして作製した造粒粉末を粒径４５μｍ未満のものと、４５μｍ以上１５０μｍ以下、１５０μｍ以上〜３００μｍ以下、３００μｍ以上〜５００μｍ以下、５００μｍを超えるもの、４５μｍ以上〜３００μｍ以下のもの、４５μｍ以上〜５００μｍ以下のものとに分級し、流動性試験（ＪＩＳ ２５０２−１９５８）に用いた。
【０１５０】
その結果、造粒粉末の粒径が４５μｍ未満の場合は流れない、４５μｍ以上１５０μｍ以下の場合は４４．５秒、１５０μｍ以上〜３００μｍ以下の場合は５０．４秒、３００μｍ以上〜５００μｍ以下の場合は６１．８秒、５００μｍを超える場合は流れない、４５μｍ以上〜３００以下の場合は４５．９秒、４５μｍ以上〜５００μｍ以下の場合は５０．０秒であった。
従って造粒粉末の粒径は、４５μｍ以上５００μｍ以下が好ましく、４５μｍ以上３００μｍ以下がより好ましく、４５μｍ以上１５０μｍ以下がさらに好ましいことがわかる。
【０１５１】
（実験例７）
全造粒粉末に占める粒径４５μｍ未満の造粒粉末の混入量（重量％）と、流動性について調べた。結果を図５に示す。ここでの流動性は、直径２．５ｍｍの孔内に造粒粉末を流し込む際、全造粒粉末５０ｇに占める粒径４５μｍ未満の造粒粉末の混入量を変更し、孔内を通過する時間（秒）を測定した。ここで用いた造粒粉末は、実施形態の非晶質軟磁性合金粉末９８．３重量％に対し、絶縁材としてシリコーン樹脂を１．４重量％と潤滑剤としてステアリン酸亜鉛を０．３重量％とを混合、造粒したものである。このようにして作製した造粒粉末を粒径４５μｍ未満のものと、粒径４５μｍを越より大きく、５００μｍ以下のものとに分級し、流動性試験（ＪＩＳ ２５０２−１９５８）に用いた。
図５に示す結果から粒径４５μｍ未満の造粒粉末の混入量が、全造粒粉末の１７重量％以下であれば流動性が６０秒以下であり、１５重量％以下であれば流動性が５０秒以下にでき流動性が優れていることがわかる。
【０１５２】
（実験例８）
上記の実験例４で作製したＮｏ．２３の軟磁性合金粉末（組成はＦｅ_{７４．４３}Ｃｒ_１．９６Ｐ_９．０４Ｃ_２．１６Ｂ_７．５４Ｓｉ_４．８７）を用いる以外は上記実験例１と同様にして造粒粉末を作製し、さらにこれら造粒粉末を用いて上記実験例１と同様にして実施例の圧粉コアを作製した。
また、比較のためにＦｅの粉末を用いる以外は上記実験例１と同様にして造粒粉末を作製し、さらにこれら造粒粉末を用いて上記実験例１と同様にして圧粉コア（比較例１）を作製した。
さらに、比較のために従来一般的に低損失のコアに使われているＮｉ−Ｆｅ−Ｍｏ（Ｍｏ系パーマロイ）の粉末を用いる以外は上記実験例１と同様にして造粒粉末を作製し、さらにこれら造粒粉末を用いて上記実験例１と同様にして圧粉コア（比較例２）を作製した。また、Ｆｅ−Ａｌ−Ｓｉ（センダスト）の粉末を用いる以外は上記実験例１と同様にして造粒粉末を作製し、さらにこれら造粒粉末を用いて上記実験例１と同様にして圧粉コア（比較例３）を作製した。
【０１５３】
得られた各種の圧粉コアのコアロス（Ｗ）、相対実効透磁率（μ’）、直流重畳特性（μ’）を測定した。
ここでのコアロスは、周波数（ｆ）１００ｋＨｚと一定とし、飽和磁束密度（Ｂｍ）１０〜１００ｍＴの条件で測定したときのものである。
また、相対実効透磁率は、周波数（ｆ）１〜１０００ｋＨｚの範囲で変更したときの実効透磁率（μ’）の測定結果を相対値で表したしたものである。
また、直流重畳特性は、電流１ｍＡ、周波数（ｆ）１００ｋＨｚと一定とし、直流バイアス磁界（Ｈｍ）を０〜８０００Ａｍ^−１の範囲で変更したときの実効透磁率（μ’）を測定したものである。結果を図１４〜図１６に示す。
また、得られた各種の圧粉コアの比抵抗（ρ）を測定したところ、実施例の圧粉コアは３０７ｋΩ・ｃｍ、比較例２の圧粉コアは０．５Ω・ｃｍ、比較例３の圧粉コアは１．７ｋΩ・ｃｍであった。
【０１５４】
図１４の結果からＮｏ．２３の軟磁性合金粉末を用いた実施例の圧粉コアは、Ｆｅの粉末を用いた比較例１の圧粉コアや、Ｎｉ−Ｆｅ−Ｍｏの粉末やＦｅ−Ａｌ−Ｓｉの粉末を用いた比較例２〜３に比べてコアロスが低いことがわかる。
また、コアは使用周波数の範囲で透磁率が一定であることが好ましいが、図１５の結果から１ｋＨｚ〜１０００ｋＨｚ（１ＭＨｚ）の範囲ではＦｅの粉末やＮｉ−Ｆｅ−Ｍｏの粉末を用いた比較例１〜２の圧粉コアは周波数が高くなると実効透磁率の低下割合がおおきい。これに対してＮｏ．２３の軟磁性合金粉末を用いた実施例の圧粉コアは、周波数が１ｋＨｚ〜１０００ｋＨｚでは実効透磁率がほぼ一定であり、また、上記周波数の範囲ではＦｅ−Ａｌ−Ｓｉの粉末を用いた比較例３の圧粉コアよりも実効透磁率が高い。
また、コアを使用するときは、直流バイアス磁界がおおきくなっても透磁率はできるだけ一定を維持できるのが好ましいとされているが、図１６の結果からＮｉ−Ｆｅ−Ｍｏの粉末を用いた比較例２の圧粉コアは磁界が大きくなると急激に実効透磁率が低下してしまうため使い難いことがわかる。これに対して実施例の圧粉コアは、Ｆｅの粉末やＦｅ−Ａｌ−Ｓｉの粉末を用いた比較例１や比較例３の圧粉コアと同様に磁界がおおきくなっても実効透磁率の低下割合が小さい。
これらのことより本発明の軟磁性合金粉末を用いた実施例の圧粉コアは、コアロスが低く、周波数が高いところまで一定の透磁率を示すことができ、コアとして用いる場合に特性が安定しており、使い易い。
【０１５５】
（実験例９）
上記実験例４で作製したＮｏ．２３の略球形軟磁性合金粉末を用いる以外は上記実験例１と同様にして造粒粉末を作製し、さらにこれら造粒粉末を用いて上記実験例１と同様にして実施例の圧粉コアを作製した。
また、比較として上記実験例５で作製したＮｏ．５６の不定形軟磁性合金粉末（組成はＦｅ_{７４．４３}Ｃｒ_１．９６Ｐ_９．０４Ｃ_２．１６Ｂ_７．５４Ｓｉ_４．８７）を用いる以外は上記実験例１と同様にして造粒粉末を作製し、さらにこれら造粒粉末を用いて上記実験例１と同様にして圧粉コア（比較例４）を作製した。
作製した実施例と比較例４の圧粉コアについてコアロス（Ｗ）、初期実効透磁率（μ’）、直流重畳特性（μ’）を測定した。
ここでのコアロスは、飽和磁束密度（Ｂｍ）０．１Ｔと一定とし、周波数（ｆ）１０〜２００ｋＨｚの範囲で変更したときのものである。
また、初期実効透磁率は、周波数（ｆ）１〜１０００ｋＨｚの範囲で変更したときの実効透磁率（μ’）を測定したものである。
また、直流重畳特性は、電流１ｍＡ、周波数（ｆ）１００ｋＨｚと一定とし、直流バイアス磁界（Ｈｍ）を０〜８０００Ａｍ^−１の範囲で変更したときの実効透磁率（μ’）を測定したものである。結果を図１７〜図１９に示す。
また、実施例と比較例４の圧粉コアの密度（Ｄ）の測定結果を図２０に示す。
【０１５６】
図１７の結果から形状が略球形のＮｏ．２３の軟磁性合金粉末を用いた実施例の圧粉コアは、周波数１０〜２００ｋＨｚの範囲では、形状が不定形のＮｏ．５６の軟磁性合金粉末を用いた実施例の圧粉コアに比べてコアロスが低いことがわかる。
また、先に述べたようにコアは使用周波数の範囲で透磁率が一定であることが好ましいが、図１８の結果から１ｋＨｚ〜１０００ｋＨｚの範囲では比較例４の圧粉コアは、周波数が高くなるにつれて初期実効透磁率の低下割合がおおきくなっている。これに対して実施例の圧粉コアは、上記の周波数の範囲では略一定の初期実効透磁率を示しており、コアとして用いる場合に使い易い。
また、図１９の結果から比較例４のものは印加する磁界が大きくなると急激に実効透磁率が低下している。これに対して実施例の圧粉コアは、印加する磁界が大きくなっても初期実効透磁率の低下割合が小さく、しかも２５００Ａｍ^−１ 以上では比較例４に比べて初期実効透磁率が大きいことがわかる。
また、図２０の結果から比較例４の圧粉コアは密度が約５．５ｇ／ｃｍ^３であるが、実施例の圧粉コアの密度は約６ｇ／ｃｍ^３であり、比較例４のものに比べて密度が大きいことがわかる。
これらのことより実施例と比較例４の圧粉コアとは、組成が同じ軟磁性合金粉末を用いているが、合金粉末の形状が異なることにより、上記のような特性に違い出ており、従って、略球状の軟磁性合金粉末を用いた方がコアロスが低く、周波数が１０００ｋＨｚまで一定の透磁率を示すことができ、コアとして用いる場合に特性が安定しており、使い易いことがわかる。
【０１５７】
（実験例１０）
上記実験例４で作製したＮｏ．２３の略球形軟磁性合金粉末をアトライタに投入し、アトライタダイアル４で１２時間粉砕混合することにより、実施例の扁平型軟磁性合金粉末を作製した。ここで作製した実施例の扁平型非晶質軟磁性合金粉末は、厚さが約０.３〜１μｍの範囲であり、長径が約１０〜７６μｍの範囲であった。図２１に、作製した実施例の扁平型軟磁性合金粉末をＳＥＭにより観察した結果を示す。図２１から形状が略球形のＮｏ．２３の軟磁性合金粉末を扁平化したものは、円盤に近い形状であり、しかも大きさが揃っていることがわかる。
ついで、実施例の扁平型軟磁性合金粉末４５重量％に対し、絶縁性と結着剤をかねる材料としてをシリコーンエラストマーを５５重量％混合し、シート状に固化成形して実施例の電波吸収体を作製した。
【０１５８】
また、比較のために上記実験例５で作製したＮｏ．５６の不定形軟磁性合金粉末をアトライタに投入し、アトライタダイアル１０で１６時間粉砕混合することにより、比較例の扁平型軟磁性合金粉末を作製した。作製した比較例の扁平型軟磁性合金粉のうち径６３〜１０６μｍのものを分級した。図２２に、分級した比較例の扁平型軟磁性合金粉末をＳＥＭにより観察した結果を示す。図２２から形状が不定形のＮｏ．５６の軟磁性合金粉末を扁平化したものは、細かくちぎれてしまい、しかも大きさも不均一であることがわかる。
ついで、分級した比較例の扁平型軟磁性合金粉末４５重量％に対し、絶縁性と結着剤をかねる材料としてシリコーンエラストマーを５５重量％混合し、シート状に固化成形して比較例の電波吸収体を作製した。
【０１５９】
作製した実施例と比較例の電波吸収体について周波数を１ＭＨｚ〜１０００ＭＨｚの範囲で変更したときの実効透磁率（μ’）と虚数透磁率（μ”）を測定した。結果を図２３に示す。
図２３の結果からＮｏ．２３の略球形軟磁性合金粉末を扁平化した粉末を用いた実施例の電波吸収体は、２ＭＨｚ〜１０００ＭＨｚの範囲においてＮｏ．５６の不定形軟磁性合金粉末を扁平化した粉末を用いた比較例の電波吸収体に比べて実効透磁率が高くなっていることがわかる。また、実施例の電波吸収体は、７ＭＨｚ〜１０００ＭＨｚの範囲において比較例の電波吸収体に比べて虚数透磁率が高くなっており、電磁波抑制効果が優れていることがわかり、特に２０ＭＨｚ以上でμ”が１５以上（最高１８）の値を得ることが可能であることがわかる。
【０１６０】
【発明の効果】
以上、詳細に説明したように本発明の非晶質軟磁性合金粉末は、水アトマイズ法により形成された略球状粉末であり、略球状粉末の平均粒径（Ｄ _５０ ）が４４ . ３２μｍ以下、前記略球状粉末のタップ密度が３ . ７８Ｍｇ／ｍ ^３ 以上、前記略球状粉末は酸素濃度が２９００ｐｐｍ以下、前記略球状粉末は比表面積が０ . ２８ｍ ^２ ／ｇ以下であり、
Ｆｅ_{１００−ｘ−ｙ−ｚ−ｗ−ｔ}Ｍ_ｘＰ_ｙＣ_ｚＢ_ｗＳｉ_ｔの組成式で示され（ただし、ＭはＣｒ、Ｍｏ、Ｗ、Ｖ、Ｎｂ、Ｔａ、Ｔｉ、Ｚｒ、Ｈｆ、Ｐｔ、Ｐｄ、Ａｕより選ばれる１種または２種以上の元素であり）、組成比を示すｘ、ｙ、ｚ、ｗ、ｔが、０．５原子％≦ｘ≦８原子％、２原子％≦ｙ≦１５原子％、０原子％＜ｚ≦８原子％、１原子％≦ｗ≦１２原子％、４.３７原子％≦ｔ≦８原子％、７０原子％≦（１００−ｘ−ｙ−ｚ−ｗ−ｔ）≦７９原子％としたものであるので、高い飽和磁化と低いコアロスを兼ね備えており、しかも本発明の非晶質軟磁性合金粉末は水アトマイズ法により製造できるので、製造装置の大型化が可能であり、しかも合金溶湯を高圧水で粉砕可能であるので量産性を向上でき、また、高価な不活性ガスを使用しなくても済むので製造コストを低減できる。
この非晶質軟磁性合金粉末は、水アトマイズ法により球形状に近い形状に形成されたものであるので、嵩密度が高く、表面の凹凸が少ないという利点がある。
本発明において、前記略球状粉末の平均粒径（Ｄ_５０）が８.６３μｍ以上、かつ４４.３２μｍ以下である場合が好ましい。
かかる構成の非晶質軟磁性合金粉末によれば、周波数１００ｋＨｚ、磁束密度０.１Ｔの条件で測定したときのコアロス（Ｗ）を２１３ｋＷ／ｍ^３以下とすることが可能であり、また、周波数１ＭＨｚまでの複素透磁率の実数部μ’を６０〜７０とほぼ一定にでき、直流バイアス磁界５５００Ａｍ^−１のときの直流重畳特性（μ’_{ＤＣ５５００}）を３０〜３４.５とほぼ一定にできるため、磁心に用いる場合に使い易い非晶質軟磁性合金粉末を提供できる。
また、本発明において先の非晶質軟磁性合金粉末を用いてなる圧粉コアあるいは電波吸収体であるならば、上述した優れた特性を兼ね備えた圧粉コアあるいは電波吸収体を提供できる。
【図面の簡単な説明】
【図１】 本発明の非晶質軟磁性合金粉末の製造に用いる高圧水噴霧装置の一例を示す断面模式図である。
【図２】 本発明の圧粉コアの第１の実施形態例を示す斜視図である。
【図３】 本発明の圧粉コアの製造に用いる金型の一例を示す分解斜視図である。
【図４】 本発明の圧粉コアの製造する際に用いる放電プラズマ焼結装置の要部の模式図である。
【図５】 粒径４５μｍ未満の造粒粉末の混入量と流動性の関係を示すグラフである。
【図６】 本発明の圧粉コアのその他の実施形態例を示す斜視図である。
【図７】 本発明の圧粉コアのその他の実施形態例を示す斜視図である。
【図８】 Ｎｏ．２３の軟磁性合金粉末の電子線回折の結果を示す図である。
【図９】 Ｎｏ．５７の軟磁性合金粉末の電子線回折の結果を示す図である。
【図１０】 Ｎｏ．２３の軟磁性合金粉末のＳＥＭ写真である。
【図１１】 Ｎｏ．５６の軟磁性合金粉末のＳＥＭ写真である。
【図１２】 Ｎｏ．２３の軟磁性合金粉末のＴＥＭ写真である。
【図１３】 Ｎｏ．５７の軟磁性合金粉末のＴＥＭ写真である。
【図１４】 実施例と比較例１〜３の圧粉コアのコアロスの測定結果を示す図である。
【図１５】 実施例と比較例１〜３の圧粉コアの相対実効透磁率の測定結果を示す図である。
【図１６】 実施例と比較例１〜３の圧粉コアの直流重畳特性の測定結果を示す図である。
【図１７】 実施例と比較例４の圧粉コアのコアロスの測定結果を示す図である。
【図１８】 実施例と比較例４の圧粉コアの初期実効透磁率の測定結果を示す図である。
【図１９】 実施例と比較例４の圧粉コアの直流重畳特性の測定結果を示す図である。
【図２０】 実施例と比較例４の圧粉コアの密度の測定結果を示す図である。
【図２１】 実施例の扁平型軟磁性合金粉末のＳＥＭ写真である
【図２２】 比較例の扁平型軟磁性合金粉末のＳＥＭ写真である。
【図２３】 実施例と比較例の電波吸収体の実効透磁率と虚数透磁率の周波数依存性を示す図である。
【符号の説明】
１…高圧水噴霧装置、２…溶湯るつぼ、３…水噴霧器、４…チャンバ、５…合金溶湯、６…溶湯ノズル、７…導入流路、８…水噴射ノズル、１０…高圧水、２１，３１，４１…圧粉コア、ｇ…高圧水流、ｐ…噴霧点、θ…水噴射角。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an amorphous soft magnetic alloy powder, a dust core and a radio wave absorber using the same, and in particular, a nearly spherical amorphous soft magnetic alloy powder that can be produced by a water atomization method and the same. The present invention relates to the dust core and the wave absorber used.
[0002]
[Prior art]
Conventionally, an alloy having a composition of TM-Al-Ga-P-C-B-Si system or the like (TM is a transition metal element such as Fe, Co, Ni, etc.) has been obtained by rapidly cooling the molten alloy. These are known to form amorphous soft magnetic alloys (see, for example, Patent Documents 1 and 3). In particular, this amorphous soft magnetic alloy having a specific composition has a wide supercooled liquid state in the temperature range before crystallization, and is known to constitute a so-called glassy alloy. It has been.
This metallic glass alloy exhibits excellent soft magnetic properties, and can form a bulk material having a much thicker bulk than an amorphous soft magnetic alloy ribbon manufactured by a liquid quenching method.
[0003]
By the way, conventionally, since the metal glass is manufactured by means such as a liquid quenching method exemplified by a single roll method, the alloy itself is required to have a certain degree of amorphous forming ability.
Therefore, the development of metallic glass is mainly aimed at improving the amorphous forming ability of the alloy, and is proceeding from the viewpoint of searching for an alloy composition that can achieve this purpose.
However, since the composition capable of increasing the amorphous forming ability of the alloy does not necessarily coincide with the alloy composition capable of increasing the soft magnetic characteristics, further improvement is required to improve the high saturation magnetization and the soft magnetic characteristics. There is room for it.
Moreover, since the conventional metallic glass is not suitable for mass production because it uses expensive Ga, a composition that can achieve cost reduction is desired.
[0004]
In addition, the metallic glass produced by a single roll method or the like has been obtained in the form of a ribbon having a thickness of about 2200 μm. When this thin ribbon metal glass is applied to a magnetic core such as a transformer or a choke coil, as an example, the ribbon is pulverized into a powder, and a binder such as a resin is mixed with the powder, The green compact core is manufactured by solidifying and molding into the shape.
Since the powder obtained here is obtained by pulverizing the ribbon, it contains a large amount of flake-like irregularly shaped powder, so the molding density of the magnetic core is low, and the insulation between the powders In some cases, the magnetic properties of the magnetic core itself deteriorate.
As other prior art documents related to the invention of this application, there are patent documents 5 to 8.
[0005]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 08-333660
[Patent Document 2]
Japanese Patent Laid-Open No. 08-037107
[Patent Document 3]
JP 09-256122 A
[Patent Document 4]
Japanese Patent No. 2574174
[Patent Document 5]
JP 63-117406 A
[Patent Document 6]
JP-A-57-185957
[Patent Document 7]
Japanese Patent Laid-Open No. 06-158239
[Patent Document 8]
Japanese Laid-Open Patent Publication No. 01-156452
[0006]
[Problems to be solved by the invention]
In order to solve the above problems, alloy powders such as Fe-Al-Si alloys and Mo permalloy have been proposed (see, for example, Patent Document 2). As a method for producing such a soft magnetic alloy powder, a gas atomizing method or a water atomizing method in which molten alloy is sprayed with an inert gas and rapidly cooled is employed.
According to the Fe—Al—Si based alloy powder and the Mo permalloy powder, the Fe—Al—Si based alloy powder has a relatively low core loss, but has a low saturation magnetization and a direct current superposition characteristic. Getting worse. Mo permalloy has a high core loss, and there is room for improvement in practice. Therefore, in order to solve such problems, it was expected that a powder core having both high saturation magnetization and low core loss could be obtained by making Fe-based amorphous alloy into powder. The powder shape has not been optimized, and a powder core using an amorphous alloy powder has not yet been obtained with good magnetic properties.
[0007]
According to the above gas atomization method, an amorphous soft magnetic alloy powder having a spherical shape and a small amount of impurities (low oxygen content) can be obtained, but a large amount of expensive inert gas is pulverized and cooled for cooling. Since it is used, the manufacturing cost is increased. In addition, since the molten alloy is pulverized with an inert gas, it is difficult to make a large-scale manufacturing apparatus. Further, since the inert gas is supplied from a gas cylinder, the pulverization pressure can only be increased to about 20 MPa, thereby improving the production efficiency. It was difficult to raise. Therefore, the spherical amorphous soft magnetic alloy powder produced by the gas atomization method has a problem that it is expensive to produce and is not suitable for mass production.
[0008]
Adopting a water atomization method performed in an air atmosphere instead of the atomization method as described above has been studied. If the water atomization method is adopted, it is possible to increase the size of the manufacturing equipment and improve the mass productivity because the molten alloy can be pulverized at a high pressure. In general, the water atomization method uses an inert gas. Since the cooling rate is higher than that of the amorphous alloy powder, the amorphous alloy powder obtained by using the water atomization method is amorphous and cannot be spherical.
The gas atomization method can produce Fe-Si-B-based spherical amorphous alloy powder and Co-based spherical amorphous alloy powder, but a general water atomization method with a high cooling rate has the above composition. It was difficult to produce a spherical amorphous alloy powder.
Since such amorphous amorphous alloy powder has many irregularities on the surface, the molding density is low, and when solidified by mixing with the above binder, it is very difficult to obtain insulation between the powders. Thus, a compact core with good characteristics cannot be obtained. In addition, if the amorphous alloy powder is indefinite, the amorphous alloy powder processed by an attritor is solidified and formed into a sheet with the above binder, and then processed by an attritor. In this case, since the amorphous alloy powder is finely broken, it is difficult to control the particle size, and a radio wave absorber having good characteristics cannot be obtained.
In addition, manufacturing a soft magnetic alloy powder close to a spherical shape by the water atomization method is proposed in, for example, Patent Document 4, but the alloy powder obtained by this water atomization method is Fe-Ni-Cr-Si. Since it is a -B type and has a high mixing ratio of crystal phases, a process for further amorphization is necessary. In Patent Document 4, this alloy powder is pulverized by a medium stirring mill and flattened. Amorphization is performed at the time of conversion, and foreign substances from the mill tend to be mixed in, the characteristics are deteriorated, and the number of processes is increased.
[0009]
The present invention has been made in view of the above circumstances, and has both a high saturation magnetization and a low core loss, and has a nearly spherical amorphous soft magnetic alloy powder that can be manufactured by a water atomization method, and a dust core using the same And it aims at providing an electromagnetic wave absorber.
In addition, the present invention has a low-cost amorphous soft magnetic alloy powder that has both high saturation magnetization and low core loss without adding expensive Ga and the like, can be manufactured by a water atomization method, and uses the same. Another object is to provide a dust core and a radio wave absorber.
[0010]
[Means for Solving the Problems]
  In order to achieve the above object, the present invention employs the following configuration.
  The amorphous soft magnetic alloy powder of the present invention is a substantially spherical powder formed by a water atomization method, and the powder contains Fe as a main component and contains at least P, C, B, and Si, and Cr, Mo, One or more elements of W, V, Nb, Ta, Ti, Zr, Hf, Pt, Pd, and Au are included as an M element, represented by the following composition formula, and ΔTx = Tx−Tg ( However, Tx represents the crystallization start temperature, and Tg represents the glass transition temperature.) Only from the amorphous phase in which the temperature interval ΔTx of the supercooled liquid represented by the formula:Become
  Average particle diameter (D ₅₀ 44) . 32 μm or less, the tap density of the substantially spherical powder is 3 . 78Mg / m ³ As described above, the substantially spherical powder has an oxygen concentration of 2900 ppm or less, and the substantially spherical powder has a specific surface area of 0. . 28m ² / G or lessIt is characterized by that.
  Fe_100-xyz-wtM_xP_yC_zB_wSi_t
  However, x, y, z, w, and t indicating the composition ratio are 0.5 atomic% ≦ x ≦ 8 atomic%, 2 atomic% ≦ y ≦ 15 atomic%, 0 atomic% <z ≦ 8 atomic%, Atomic% ≦ w ≦ 12 atomic%, 4.37 atomic% ≦ t ≦ 8 atomic%, 70 atomic% ≦ (100−x−yz−w−t) ≦ 79 atomic%.
[0011]
Since the amorphous soft magnetic alloy powder having the above-described configuration includes Fe exhibiting magnetism and metalloid elements such as P, C, and B having an amorphous forming ability, the amorphous phase is the main phase. In addition, it is possible to construct amorphous soft magnetic alloy powder that exhibits excellent soft magnetic properties, and can be manufactured by a water atomization method performed in an air atmosphere, so that the molten alloy is compared with a gas atomization method using an inert gas. Thus, it becomes possible to form an amorphous soft magnetic alloy powder in which the entire structure is completely in an amorphous phase. In addition, the amorphous soft magnetic alloy powder of the present invention can be made amorphous even if no expensive element such as Ga is added, so that the cost can be reduced, and furthermore, high saturation magnetization and low core loss. It is also possible to have both.
The substantially spherical amorphous soft magnetic alloy powder can be produced by the water atomization method because the amorphous soft magnetic alloy molten metal (molten alloy) used for producing the amorphous soft magnetic alloy powder of the present invention is Since the amorphous soft magnetic alloy powder of the present invention has the same or substantially the same composition, it contains an element having an amorphous forming ability as described above, and the temperature interval ΔTx of the supercooled liquid is 20K or more. Therefore, when high pressure water is sprayed from the water injection nozzle to the above molten alloy (molten alloy) in the air atmosphere and pulverized and cooled, a wide supercooled liquid region can be obtained even if the cooling rate is somewhat slow. As the temperature decreases without crystallization, the amorphous phase can be easily formed up to the glass transition temperature Tg, and the cooling rate when cooling the molten alloy is sufficient for the surface tension of the molten alloy. Sphere by making it act to the extent that -Like amorphous soft magnetic alloy powder can be obtained. The cooling rate of the molten alloy can be changed by controlling the injection pressure of water, the injection flow rate (inner diameter of the molten metal nozzle), the molten alloy flow rate, and the like. Further, when producing the substantially spherical amorphous soft magnetic alloy powder of the present invention, in addition to the cooling rate of the molten alloy, the water injection nozzle slit width, the water injection nozzle tilt angle, the water injection angle, the temperature of the molten alloy, Viscosity, atomizing point (powdering point distance), etc. are controlled.
[0012]
In addition, since the amorphous soft magnetic alloy powder having the above structure can be produced by a water atomizing method, the production apparatus can be enlarged, and the molten alloy can be pulverized with high-pressure water, so that mass productivity can be improved. Further, it is not necessary to use an expensive inert gas, so that the manufacturing cost can be reduced.
Furthermore, since the amorphous soft magnetic alloy powder having the above structure is formed in a shape close to a spherical shape by the water atomization method, the bulk density is high and the surface irregularities are small, so that the molding density can be increased. When solidified by mixing with an insulating material such as a resin in order to produce a dust core or the like, insulation between the powders can be maintained, which is useful as a soft magnetic alloy powder for producing a dust core.
In addition, since the amorphous soft magnetic alloy powder having the above-mentioned configuration has a shape close to a spherical shape, in order to produce a radio wave absorber, when processing this amorphous soft magnetic alloy powder with an attritor or the like, Since flattened particles having a uniform shape are obtained and the particle size is easy to control, it is useful as a soft magnetic alloy powder for preparing a radio wave absorber.
[0013]
In the amorphous soft magnetic alloy powder of the present invention, the substantially spherical powder is one or two of Cr, Mo, W, V, Nb, Ta, Ti, Zr, Hf, Pt, Pd, and Au. It is preferable to contain more than one element.
Passivation oxide film is formed on amorphous soft magnetic alloy powder surface by adding one or more elements of Cr, Mo, W, V, Nb, Ta, Ti, Zr, Hf And has the effect of improving the corrosion resistance.
Since Pt, Pd, and Au are noble metal elements, the addition of Pt, Pd, or Au has the effect of improving the corrosion resistance by dispersing these noble metal elements on the surface of the amorphous soft magnetic alloy powder.
[0014]
In the amorphous soft magnetic alloy powder of the present invention, the substantially spherical powder preferably has an average aspect ratio of 1 or more and 3 or less.
When the average aspect ratio of the substantially spherical powder exceeds 3, the amorphous amorphous soft magnetic alloy powder increases and the molding density is difficult to increase. Further, the amorphous soft magnetic alloy powder is used for compacting. When forming a molded body such as a core, it becomes difficult to take insulation of the powder.
[0015]
In the amorphous soft magnetic alloy powder of the present invention, the substantially spherical powder has an average particle diameter (D₅₀) Is preferably 45 μm or less. Average particle diameter (D₅₀) Is the cumulative 50% particle size (median diameter).
D of the above substantially spherical powder₅₀If the particle diameter exceeds 45 μm, eddy currents in the powder grains are generated, the core loss increases, and if the particle diameter is larger than 45 μm, the powder shape gradually becomes irregular, making it difficult to obtain a nearly spherical powder.
D of the above substantially spherical powder₅₀Can be controlled by controlling production conditions such as water injection pressure when producing the amorphous soft magnetic alloy powder of the present invention by the water atomization method.
[0016]
In the amorphous soft magnetic alloy powder of the present invention, the substantially spherical powder has a tap density of 3.7 Mg / m.³The above is preferable in that the magnetic permeability and direct current superposition characteristics of the dust core (magnetic core) produced using this amorphous soft magnetic alloy powder are improved and the strength of the molded body is increased. The tap density here is measured by the Japan Powder Metallurgy Industry Association Group Standard JPMAP08-1992 metal powder tap density test method (issued in March 1992). The larger the tap density, the closer to the spherical shape. I understand.
The tap density of the substantially spherical powder is 3.7 Mg / m³If it is less than the density, the density of the compact produced using the amorphous soft magnetic alloy powder will be low.
The tap density of the substantially spherical powder can be controlled by controlling the production conditions such as the water injection angle when producing the amorphous soft magnetic alloy powder of the present invention by the water atomization method. In particular, the tap density of the amorphous soft magnetic alloy powder is easily affected by the water injection angle θ, and the tap density increases as the water injection angle decreases. However, if the water injection angle becomes too small, the molten metal crushing ability is lowered, the particle size of the resulting amorphous alloy powder is increased, the cooling ability is lowered, and the yield is lowered.
[0017]
In the amorphous soft magnetic alloy powder of the present invention, the substantially spherical powder preferably has an oxygen concentration of 3000 ppm or less. When producing an amorphous soft magnetic alloy powder by the water atomization method, high pressure water is injected into the molten amorphous soft magnetic alloy having the same or substantially the same composition as the amorphous soft magnetic alloy powder to be produced, and then pulverized and cooled. Then, after forming a substantially spherical powder, it is dried, but since these steps are performed in the atmosphere, oxygen is likely to be mixed into the amorphous soft magnetic alloy powder as compared with the case where it is manufactured by the gas atomization method. , Oxygen is easily mixed in the drying process.
When the oxygen concentration of the substantially spherical powder exceeds 3000 ppm, the oxygen concentration becomes too high and rust is easily generated on the powder surface, and the magnetic properties of the amorphous soft magnetic alloy powder are deteriorated. Loss of the magnetic core produced using the soft magnetic alloy powder increases, and the magnetic permeability decreases.
[0018]
In the amorphous soft magnetic alloy powder of the present invention, the substantially spherical powder has a specific surface area of 0.30 m.²/ G or less is preferable. The specific surface area here is measured by the BET method. The BET method is a method in which molecules with a known adsorption occupation area are adsorbed on the surface of powder particles at the temperature of liquid nitrogen, and the specific surface area of the sample is obtained from the amount, and the most frequently used is the low temperature of an inert gas. A BET method using low-humidity physical adsorption is adopted.
As the specific surface area of the substantially spherical powder increases, the powder shape has more irregularities and the oxygen concentration increases, so the upper limit of the specific surface area is 0.30 m.²/ G makes it possible to obtain a substantially spherical amorphous soft magnetic alloy powder in which rust does not easily occur. Moreover, if the specific surface area of the substantially spherical powder is high, it becomes difficult to insulate the powder, and the molding density of the magnetic core produced using this amorphous soft magnetic alloy powder will decrease. The specific surface area of the amorphous soft magnetic alloy powder is 0.30 m.²/ G or less can improve the magnetic permeability and DC superimposition characteristics of a magnetic core produced using soft magnetic alloy powder.
[0019]
  In the amorphous soft magnetic alloy powder of the present invention, the substantially spherical powder has an average particle diameter (D₅₀)But8 . 63μmmore thanAnd 44 . 32below μmRumoIt may be.
  According to the amorphous soft magnetic alloy powder having such a configuration, the core loss (W) when measured under the conditions of a frequency of 100 kHz and a magnetic flux density of 0.1 T is obtained.213kW / m³And the real part μ ′ of the complex permeability up to a frequency of 1 MHz is60~70DC bias magnetic field 5500 Am^-1DC superposition characteristics (μ ′_DC5500) Can be made substantially constant from 30 to 34.5, and is easy to use when used in a magnetic core.
[0020]
In the amorphous soft magnetic alloy powder of the present invention, the substantially spherical powder has an average particle diameter (D₅₀) Is larger than 4 μm and not larger than 16 μm, and the tap density is 4.0 Mg / m.³The specific surface area is 0.23m²/ G or less, and the oxygen concentration is preferably 2000 ppm or less.
According to the amorphous soft magnetic alloy powder having such a configuration, the core loss (W) when measured under conditions of a frequency of 100 kHz and a magnetic flux density of 0.1 T is 250 kW / m.³Further, the real part μ ′ of the complex permeability up to a frequency of 1 MHz can be made substantially constant as 57 to 75, and the DC bias magnetic field 5500 Am^-1DC superposition characteristics (μ ′_DC5500) Can be made substantially constant at 30 to 36, and therefore, preferable characteristics can be provided when used in a magnetic core.
[0022]
Further, in the amorphous soft magnetic alloy powder of the present invention, y, z, w, and t indicating the composition ratio in the composition formula satisfy the relationship of 17 atomic% ≦ (y + z + w + t) ≦ 29.5 atomic%. It is preferable.
[0023]
  Further, in the amorphous soft magnetic alloy powder of the present invention, x, y, z, w, and t indicating the composition ratio in the above composition formula are 1 atomic% ≦ x ≦ 4 atomic%, 4 atomic% ≦ y. ≦ 14 atomic%, 0 atomic% <z ≦ 6 atomic%, 2 atomic% ≦ w ≦ 10 atomic%,4 . 37It is preferable to satisfy the relationship of atomic% ≦ t ≦ 8 atomic% and 72 atomic% ≦ (100−x−y−z−w−t) ≦ 79 atomic%.
[0024]
  Further, in the amorphous soft magnetic alloy powder of the present invention, x, y, z, w, and t indicating the composition ratio in the composition formula are 1 atomic% ≦ x ≦ 3 atomic%, 6 atomic% ≦ y. ≦ 11 atomic%, 1 atomic% ≦ z ≦ 4 atomic%, 4 atomic% ≦ w ≦ 9 atomic%,4 . 37It is preferable to satisfy the relationship of atomic% ≦ t ≦ 7 atomic% and 73 atomic% ≦ (100−x−y−z−w−t) ≦ 78 atomic%.
[0025]
The amorphous soft magnetic alloy powder represented by any one of the above composition formulas is composed of Fe and / or element T exhibiting magnetism, and a semimetal such as P, C, B, and Si having an amorphous forming ability. Since it is possible to construct an amorphous soft magnetic alloy having an amorphous phase as a main phase and exhibiting excellent soft magnetic properties, and can be produced by a water atomization method, Compared with the gas atomization method using an inert gas, the cooling rate of the molten alloy can be increased, and the amorphous soft magnetic alloy powder in which the entire structure is completely amorphous can be easily formed. Even if expensive Ga or the like is not added, the amorphous phase can be used as the main phase and excellent soft magnetic characteristics can be exhibited, so that the cost can be reduced.
[0026]
Further, the flat amorphous soft magnetic alloy powder of the present invention is characterized in that the amorphous soft magnetic alloy powder of the present invention having any one of the above structures is flattened.
Such flat amorphous soft magnetic alloy powder uses the substantially spherical amorphous soft magnetic alloy powder of the present invention with less surface irregularities, so that the amorphous alloy powder is fine when processed by an attritor or the like. It can be flattened into a uniform shape without being crushed, and flattened particles with uniform shapes can be obtained. When these flat amorphous soft magnetic alloy powders are mixed with an insulating material such as a resin to produce a radio wave absorber or the like, these powders are arranged in layers, so that they can be packed densely, The gap between can be reduced.
[0027]
Further, the dust core of the present invention is a granulated powder obtained by mixing and granulating a plurality or one of the amorphous soft magnetic alloy powders of the present invention having any one of the above structures, an insulating material, and a lubricant. The insulating material is solidified and molded as a binder.
According to such a dust core, a structure produced using the amorphous soft magnetic alloy powder of the present invention, which has excellent soft magnetic properties, has a high bulk density, has few surface irregularities, and is formed into a substantially spherical shape. By solidifying and molding the granular powder, it is possible to increase the molding density of the powder core and to maintain insulation between the powders, thereby improving the magnetic properties.
Moreover, since the amorphous soft magnetic alloy powder of the present invention produced by the water atomization method is used, mass productivity can be improved.
Also, instead of adding a lubricant after granulated powder production, by adding a lubricant at the granulated powder production stage, the slip between amorphous soft magnetic alloy powders when producing granulated powder is good, The production efficiency of the granulated powder can be improved, and since the amorphous soft magnetic alloy powder can be densely added to the granulated powder, the density of the granulated powder is improved.
Therefore, according to the dust core of the present invention, it is possible to provide a dust core having excellent mass productivity, high strength, and low loss in a high frequency region.
The dust core of the present invention can be suitably used as a choke coil for a switching power supply, a reactor for an active filter, and a magnetic core for a transformer.
[0028]
In the powder core of the present invention, the content of granulated powder having a particle size of 45 μm or more and 500 μm or less is preferably greater than 83% by weight of the total granulated powder.
When the particle size of the granulated powder is less than 45 μm, the fluidity when pouring the granulated powder into a mold for producing a compacted core is poor, mass productivity is reduced, and when it exceeds 500 μm, the core loss is increased.
In the powder core of the present invention, the content of the granulated powder having a particle size of less than 45 μm and the granulated powder having a particle size of more than 500 μm is preferably 17% by weight or less of the total granulated powder.
When the content of the granulated powder having a particle size of less than 45 μm and the granulated powder having a particle size of more than 500 μm is larger than 17% by weight of the total granulated powder, the flow when the granulated powder is poured into the mold for forming the powder core It becomes worse.
Therefore, if the content of the granulated powder having a particle size of 45 μm or more and 500 μm or less is greater than 83% by weight of the total granulated powder, the fluidity when pouring the granulated powder into the mold for forming a powder core is good. Manufacturing efficiency can be improved, and a core with a sufficiently small core loss and a high molding density can be obtained.
[0029]
In addition, the radio wave absorber of the present invention is obtained by mixing the amorphous soft magnetic alloy powder or the flat amorphous soft magnetic alloy powder of the present invention having any one of the above structures and an insulating material. And
According to such an electromagnetic wave absorber, the amorphous soft magnetic alloy powder of the present invention, which has excellent soft magnetic properties, has a high bulk density, has few surface irregularities, and is formed in a substantially spherical shape, is used. Since the insulating material can be densely packed, it is possible to improve the electromagnetic wave suppression effect in the frequency band of several hundred MHz to several GHz. Moreover, since the amorphous soft magnetic alloy powder of the present invention produced by the water atomization method is used, mass productivity can be improved.
In particular, in the case where the flat amorphous soft magnetic alloy powder (flattened particles) of the present invention is used, these particles are arranged in layers in the insulating material and can be packed more densely. The gap between the particles can be reduced, and the flattened particles have a larger aspect ratio than the amorphous spherical soft magnetic alloy powder, and the impedance of the wave absorber itself is increased. Generation of eddy current is suppressed.
Therefore, according to the radio wave absorber of the present invention, the radio wave absorber is excellent in mass productivity and has a high imaginary part μ ”of the complex permeability in the frequency band of several hundred MHz to several GHz, and the electromagnetic wave suppression effect is improved. Can be provided.
[0030]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail.
(Embodiment of amorphous soft magnetic alloy powder)
The amorphous soft magnetic alloy powder of the embodiment of the present invention is a substantially spherical powder formed by a water atomization method. The substantially spherical powder is composed of an amorphous phase containing Fe as a main component and containing at least P, C, and B. In addition, this substantially spherical powder has a ΔT_x= T_x-T_g(However, T_xIs the crystallization start temperature, T_gIndicates the glass transition temperature. The temperature interval ΔTx of the supercooled liquid represented by the equation
[0031]
The amorphous soft magnetic alloy powder of the present invention maintains the amorphous forming ability necessary for producing an amorphous powder, while maintaining the conventional Fe—Al—Ga—C—P—Si— Magnetic properties can be improved as compared with B-based alloys, and it can be formed into a nearly spherical shape by the water atomization method. Furthermore, corrosion resistance that can withstand the water atomization method can be obtained. Further, since it can be made amorphous even if Ga is not added, the cost can be reduced, and furthermore, high saturation magnetization and low core loss can be combined.
Since the amorphous soft magnetic alloy powder of the present invention comprises Fe exhibiting magnetism and metalloid elements such as P, C, and B having an amorphous forming ability, the amorphous phase is the main phase. In addition, it exhibits excellent soft magnetic properties. In addition to P, C, and B, Si may be added.
Further, even if M (Cr, Mo, W, V, Nb, Ta, Ti, Zr, Hf, Pt, Pd, or Au, one or more elemental elements) is added to improve the corrosion resistance. good.
[0032]
This amorphous soft magnetic alloy powder is a substantially spherical metallic glass alloy powder exhibiting a temperature interval ΔTx of a supercooled liquid of 20K or more. Depending on the composition, ΔTx is 30K or more, and further a remarkable temperature interval of 50K or more. In addition, soft magnetism has excellent characteristics at room temperature.
Since the amorphous soft magnetic alloy powder of the present invention contains more Fe, which is a ferromagnetic element, than the conventional Fe—Al—Ga—C—P—Si—B alloy, it exhibits high saturation magnetization.
In addition, since the substantially spherical amorphous soft magnetic alloy powder of the present invention is a complete amorphous phase, the internal stress does not precipitate without precipitation of the crystalline phase when heat-treated under appropriate conditions. The soft magnetic characteristics can be further improved.
In addition, the substantially spherical amorphous soft magnetic alloy powder of the present invention produced by the water atomizing method exhibits a saturation magnetization equivalent to or higher than that of the conventional spherical amorphous soft magnetic alloy powder produced by the gas atomizing method. Can do.
[0033]
The substantially spherical amorphous soft magnetic alloy powder can be produced by the water atomization method because the molten alloy used in the production of the amorphous soft magnetic alloy powder of the present invention (alloy in the molten state) is amorphous. Since the soft magnetic alloy powder having the same composition or substantially the same composition is used, it contains an element having an amorphous forming ability as described above, and the temperature interval ΔTx of the supercooled liquid is as large as 20 K or more. When pulverizing and cooling molten alloy (molten alloy) by the water atomization method, even if the cooling rate of the general water atomization method is reduced to the same level as the gas atomization method, it has a wide supercooled liquid region, As the temperature decreases, the glass transition temperature Tg is reached and the amorphous phase can be easily formed. In addition, the cooling rate when cooling the molten alloy is controlled so that the surface tension acts sufficiently on the molten alloy, thereby obtaining an amorphous soft magnetic alloy powder having a substantially spherical shape, that is, a small specific surface area. be able to. For this purpose, the above-described alloy composition which is not easily oxidized and can be made amorphous even at a low cooling rate is required.
[0034]
The amorphous soft magnetic alloy powder of the present invention preferably has an average aspect ratio of 1 or more and 3 or less, more preferably an average aspect ratio of 1 or more and 2 or less. More preferably, it is 1.5 or less.
The amorphous soft magnetic alloy powder of the present invention has an average particle size (D₅₀) Is preferably 45 μm or less for the reason described above, and D₅₀ Is more than 4 μm and preferably 30 μm or less, and more preferably 4 μm or more and 16 μm or less. D of amorphous soft magnetic alloy powder₅₀When the particle size is 4 μm or less, the powder yield decreases and the apparent oxygen concentration increases.
[0035]
The amorphous soft magnetic alloy powder of the present invention has a tap density of 3.7 Mg / m.³The above is preferable for the reason described above, and 3.9 Mg / m³More preferably, it is 4.0 Mg / m³More preferably, it is the above.
In addition, the amorphous soft magnetic alloy powder of the present invention preferably has an oxygen concentration of 3000 ppm or less for the reason described above, more preferably 2500 ppm or less, and further preferably 2000 ppm.
The amorphous soft magnetic alloy powder of the present invention has a specific surface area of 0.30 m for the reason described above.²/ G or less, preferably 0.26 m²/ G or less is more preferable, 0.23 m²/ G or less is more preferable.
[0036]
The amorphous soft magnetic alloy powder of the present invention has an average particle size (D₅₀) Is larger than 4 μm and not larger than 45 μm, and the tap density is 3.7 Mg / m.³The specific surface area is 0.3m²/ G or less and an oxygen concentration of 3000 ppm or less, the core loss (W) when measured under conditions of a frequency of 100 kHz and a magnetic flux density of 0.1 T is 450 kW / m.³In addition, the real part μ ′ of the complex permeability up to a frequency of 1 MHz can be made substantially constant from 57 to 80, and the DC bias magnetic field 5500 Am^-1DC superposition characteristics (μ ′_DC5500) Since it can be made substantially constant between 30 and 34.5, it is easy to use when used in a magnetic core.
[0037]
The amorphous soft magnetic alloy powder of the present invention has an average particle size (D₅₀) Is larger than 4 μm and not larger than 16 μm, and the tap density is 4.0 Mg / m.³The specific surface area is 0.23m²/ G or less, when the oxygen concentration is 2000 ppm or less, the core loss (W) when measured under the conditions of a frequency of 100 kHz and a magnetic flux density of 0.1 T is 250 kW / m.³In addition, the real part μ ′ of the complex permeability up to a frequency of 1 MHz can be made substantially constant from 57 to 75, and the DC bias magnetic field 5500 Am^-1DC superposition characteristics (μ ′_DC5500) Can be made substantially constant at 30 to 36, and therefore, preferable characteristics can be provided when used in a magnetic core.
[0038]
Examples of the substantially spherical amorphous soft magnetic alloy powder of the present invention include those represented by the following composition formula. Fe_100-xyz-wtM_xP_yC_zB_wSi_t
However, M is one or more elements selected from Cr, Mo, W, V, Nb, Ta, Ti, Zr, Hf, Pt, Pd, Au, and x, y, z indicating the composition ratio , W, t are 0.5 atom% ≦ x ≦ 8 atom%, 2 atom% ≦ y ≦ 15 atom%, 0 atom% <z ≦ 8 atom%, 1 atom% ≦ w ≦ 12 atom%, 0 atom % ≦ t ≦ 8 atomic%, 70 atomic% ≦ (100−x−y−z−w−t) ≦ 79 atomic%.
[0039]
Moreover, y, z, w, and t which show the composition ratio in the said compositional formula of the amorphous soft magnetic alloy powder represented by said compositional formula become 17 atomic% <= (y + z + w + t) <= 29.5 atomic%. It is preferable to satisfy the relationship.
[0040]
The reason for limiting the composition of the substantially spherical amorphous soft magnetic alloy powder of the present invention will be described below.
Fe is an element responsible for magnetism, and is an essential element for the amorphous soft magnetic alloy powder of the present invention.
When the composition ratio of Fe is increased, the saturation magnetization σs of the amorphous soft magnetic alloy powder can be improved.
[0041]
The addition amount of Fe is preferably 70 atom% or more and 79 atom% or less, more preferably 72 atom% or more and 79 atom% or less, and further preferably 73 atom% or more and 78 atom% or less.
When the added amount of Fe is less than 70 atomic%, the saturation magnetization σs is 150 × 10 6.^-6Since it falls to less than Wb · m / kg, it is not preferable. On the other hand, if the added amount of Fe exceeds 79 atomic%, Tg / Tm indicating the degree of amorphous forming ability of the alloy is less than 0.57, which is not preferable because the amorphous forming ability is lowered. Tm is the melting point of the alloy.
[0042]
If the added amount of Fe is 76 atomic% or more, the saturation magnetization σs of the alloy powder is 170 × 10 6.^-6Wb · m / kg or more can be achieved, and if it is 77 atomic% or more, the saturation magnetization σs of the alloy is 180 × 10^-6Wb · m / kg or more.
[0043]
Further, Cr, Mo, W, V, Nb, Ta, Ti, Zr, and Hf can form a passivated oxide film on the surface of the alloy powder, and can improve the corrosion resistance of the alloy powder.
Among these elements, Cr is most effective for improving the corrosion resistance. In the water atomization method, when the molten alloy is in direct contact with water, it is possible to prevent the occurrence of rust generated in the drying process of the alloy powder (visual level). These elements may be added alone or in combination of two or more, for example, in combination of Mo, V and Mo, Cr and V, Cr and Cr, Mo, V, etc. You may do it. Among these elements, Mo and V are slightly inferior in corrosion resistance to Cr, but the amorphous forming ability is improved. Therefore, these elements are selected as necessary. On the other hand, when the addition amount of an element selected from Cr, Mo, W, V, Nb, and Ta exceeds 8 atomic%, the magnetic characteristics (saturation magnetization) deteriorate.
[0044]
Of the elements employed as the element M in the composition formula, Zr and Hf have the highest glass forming ability. Since Ti, Zr, and Hf have strong oxidizing properties, if these elements are added in excess of 8 atomic%, melting the alloy powder raw material in the atmosphere will cause the molten metal to oxidize during melting of the raw material. (Saturation magnetization) is reduced.
[0045]
The effect of improving the corrosion resistance of the alloy powder can also be obtained by adding one or more kinds of noble metal elements selected from Pt, Pd, and Au, and by dispersing these noble metal elements on the surface of the powder, Will improve. These noble metal elements may be added alone or in combination with a combination of the above elements having an effect of improving corrosion resistance such as Cr. Since the above precious metal element does not mix with Fe, if it is added in excess of 8 atomic%, the glass forming ability is lowered, and the magnetic properties (saturation magnetization) are also lowered.
In order to give the amorphous soft magnetic alloy powder corrosion resistance, the amount of M added needs to be 0.5 atomic% or more.
[0046]
Therefore, M in the composition formula is one or more elements selected from Cr, Mo, W, V, Nb, Ta, Ti, Zr, Hf, Pt, Pd, and Au. It is preferable to use one or more of Mo, W, V, Nb, and Ta. The composition ratio x of M is preferably from 0.5 atomic% to 8 atomic%, preferably from 1 atomic% to 4 atomic%, and preferably from 1 atomic% to 3 atomic%. Is more preferable.
[0047]
C, P, B, and Si are elements that enhance the ability to form an amorphous material. By adding these elements to Fe and M to form a multi-component system, a binary system consisting of only Fe and M is used. An amorphous phase is formed more stably.
In particular, since P has a eutectic composition with Fe at a low temperature (about 1050 ° C.), the entire structure becomes an amorphous phase and the temperature interval ΔTx of the supercooled liquid is likely to appear.
Further, when P and Si are added simultaneously, the temperature interval ΔTx of the supercooled liquid becomes larger and the amorphous forming ability is improved, and the production conditions for obtaining an amorphous single-phase structure are set in a relatively simple direction. Can be relaxed.
[0048]
In the case where Si is not added, the composition ratio y of P is preferably 2 atom% or more and 15 atom% or less, more preferably 4 atom% or more and 14 atom% or less, and 6 atom% or more and 11 atom% or less. % Is most preferred. If the addition amount of P is less than 2 atomic%, an amorphous soft magnetic alloy powder cannot be obtained, and if it exceeds 15 atomic%, the saturation magnetization decreases.
If the composition ratio y of P is in the above range, the temperature interval ΔTx of the supercooled liquid is developed, and the amorphous forming ability of the alloy powder is improved.
[0049]
Moreover, since addition of Si improves the thermal stability, it is preferable to add 2 atomic% or more. On the other hand, if the amount of Si added exceeds 8 atomic%, the melting point increases. Therefore, the composition ratio t of Si is preferably 0 atomic percent or more and 8 atomic percent or more, more preferably 2 atomic percent or more and 8 atomic percent or less, and further preferably 2 atomic percent or more and 7 atomic percent or less. preferable.
[0050]
Further, when the amount of B is less than 2 atomic%, it is difficult to obtain an amorphous soft magnetic alloy powder, and when it exceeds 12 atomic%, the melting point increases. Therefore, the composition ratio w of B is preferably 1 atom% or more and 12 atom% or less, preferably 2 atom% or more and 10 atom%, more preferably 4 atom% or more and 9 atom% or less. .
[0051]
Moreover, since thermal stability improves when C is added, it is preferable to add 1 atomic% or more. On the other hand, when the addition amount of C exceeds 8 atomic%, the melting point increases. Accordingly, the composition ratio z of C is preferably more than 0 atom% and not more than 8 atom%, more preferably more than 0 atom% and not more than 6 atom%, more preferably 1 atom% to 4 atom%. More preferably.
[0052]
The total composition ratio (y + z + w + t) of these metalloid elements C, P, B and Si is preferably 17 atomic% or more and 29.5 atomic% or less, and is 18 atomic% or more and 26 atomic% or less. More preferably, it is more preferably 18 atomic% or more and 25 atomic% or less.
If the total composition ratio of the metalloid elements exceeds 29.5 atomic%, the composition ratio of Fe in particular relatively decreases, and the saturation magnetization σs decreases, which is not preferable. When the total composition ratio of the metalloid elements is less than 17 atomic%, the amorphous forming ability is lowered and it is difficult to obtain an amorphous phase single phase structure.
[0053]
Further, when the composition ratio of Fe is 76 atomic% or more, the total composition ratio (y + z + w + t) of the metalloid elements C, P, B and Si is set to 18 atomic% or more and 24 atomic% or less. The saturation magnetization σs is 170 × 10^-6Wb · m / kg or more.
Furthermore, when the composition ratio of Fe is 77 atomic% or more, the total composition ratio (y + z + w + t) of the metalloid elements C, P, B, and Si is set to 18 atomic% or more and 23 atomic% or less. The saturation magnetization σs is 180 × 10^-6Wb · m / kg or more.
[0054]
In the amorphous soft magnetic alloy powder of the present invention, Ge may be contained in the above composition in an amount of 4 atomic% or less.
In any of the above compositions, in the present invention, the temperature interval ΔTx of the supercooled liquid is 20 K or more, and depending on the composition, 35 K or more is obtained.
Further, inevitable impurities may be included in addition to the elements represented by the above composition.
[0055]
The amorphous soft magnetic alloy powder of the present invention having the above composition obtained by the water atomization method has magnetism at room temperature and exhibits better magnetism by heat treatment. Therefore, it is useful for various applications as a material having excellent soft magnetic properties.
[0056]
An example of producing the substantially spherical amorphous soft magnetic alloy powder of the present invention by the water atomization method will be described.
The water atomization method used in the present invention is a method in which an amorphous soft magnetic alloy melt having the same composition as or substantially the same composition as that of the above-mentioned amorphous soft magnetic alloy powder is atomized into the chamber together with high-pressure water in the atmosphere. It sprays, the said alloy molten metal is grind | pulverized, and it cools rapidly and manufactures a substantially spherical amorphous soft-magnetic alloy powder.
[0057]
FIG. 1 is a schematic cross-sectional view showing an example of a high-pressure water spraying apparatus suitably used for producing alloy powder by the water atomization method.
The high-pressure water spray device 1 is mainly composed of a molten crucible 2, a water sprayer 3, and a chamber 4. The high-pressure water spray device 1 is disposed in an air atmosphere.
The molten crucible 2 is filled with molten alloy 5. Further, the molten metal crucible 2 is provided with a coil 2a as a heating means, and is configured to heat the molten alloy 5 and keep it in a molten state. A molten metal nozzle 6 is provided at the bottom of the molten metal crucible 2, and the molten alloy 5 is dropped from the molten metal nozzle 6 toward the inside of the chamber 4.
[0058]
The water sprayer 3 is disposed below the molten crucible 2. The water sprayer 3 is provided with a water introduction channel 7 and a water injection nozzle 8 which is the tip of the introduction channel 7.
The high-pressure water 10 pressurized by a liquid pressurizing pump (pressurizing means) (not shown) is guided to the water injection nozzle 8 through the introduction flow path 7 and sprayed as a high-pressure water flow g from the nozzle 8 into the chamber 4. Is done.
Inside the chamber 4, the same atmospheric atmosphere as the atmosphere around the high-pressure water spray device 1 is set. The pressure inside the chamber 4 is maintained at about 100 kPa, and the temperature is maintained at about room temperature.
[0059]
In order to produce a substantially spherical amorphous soft magnetic alloy powder, first, the molten alloy 5 filled in the molten crucible 2 is dropped into the chamber 4 from the molten metal nozzle 6. At the same time, high-pressure water 10 is jetted from the water jet nozzle 8 of the water sprayer 3. The jetted high-pressure water 10 becomes a high-pressure water stream g and reaches the above-mentioned molten molten metal, collides with the molten metal at the spray point p, atomizes the molten metal, and rapidly solidifies. A substantially spherical particle powder composed of a mass phase is formed. These substantially spherical powders are stored at the bottom of the chamber 4 together with water.
[0060]
Here, the cooling rate of the molten alloy is set so that the surface tension acts sufficiently on the molten alloy. The cooling rate of the molten alloy is determined by a suitable cooling rate depending on the composition of the alloy, the particle size of the target alloy powder, etc.³-10⁵A range of about K / s can be used as a guide. Actually, whether or not a nearly spherical shape is obtained, and Fe as a crystalline phase in the glassy phase₃B, Fe₂B, Fe₃It can be determined by confirming whether a phase such as P is precipitated.
Next, after drying these substantially spherical powders in the air atmosphere, these powders are classified to obtain spherical or nearly spherical amorphous soft magnetic alloy powders having a predetermined average particle diameter.
[0061]
When producing a substantially spherical amorphous soft magnetic alloy powder by the water atomization method, the cooling rate of the molten alloy is controlled by controlling the water injection pressure, the injection flow rate, the molten alloy flow rate, etc. By controlling the manufacturing conditions by controlling the injection nozzle slit width, water injection nozzle tilt angle, water injection angle, temperature and viscosity of molten alloy, atomizing point (pulverization point distance), etc., the desired characteristics, Specifically, aspect ratio, tap density, D₅₀An amorphous soft magnetic alloy powder having an oxygen concentration and the like in the above-described range is obtained.
[0062]
The obtained amorphous soft magnetic alloy powder may be heat-treated as necessary. By performing the heat treatment, the internal stress of the alloy powder is relaxed, and the soft magnetic properties of the amorphous soft magnetic alloy powder can be further improved. The heat treatment temperature Ta is preferably in the range of not less than the Curie temperature Tc of the alloy and not more than the glass transition temperature Tg. If the heat treatment temperature Ta is lower than the Curie temperature Tc, the effect of improving the soft magnetic properties by the heat treatment cannot be obtained, which is not preferable. On the other hand, if the heat treatment temperature Ta exceeds the glass transition temperature Tg, the crystalline phase tends to be precipitated in the alloy powder structure, and the soft magnetic properties may be deteriorated.
The heat treatment time is preferably within a range in which the internal stress of the alloy powder is sufficiently relaxed and there is no fear of precipitation of the crystalline phase, and for example, a range of 30 to 300 minutes is preferred.
[0063]
Since the amorphous soft magnetic alloy powder of this embodiment can be produced by the water atomization method, the production apparatus can be enlarged, and the molten alloy can be pulverized at high pressure, so that mass productivity can be improved. Since it is not necessary to use expensive inert gas, manufacturing cost can be reduced.
Furthermore, since the amorphous soft magnetic alloy powder of the present embodiment is formed in a shape close to a spherical shape by the water atomization method, the bulk density is high and the surface unevenness is small. When solidified by mixing with an insulating material such as a resin in order to produce a powder core or the like, insulation between the powders can be maintained, which is useful as a soft magnetic alloy powder for producing a dust core.
In addition, since the amorphous soft magnetic alloy powder of the present embodiment has a shape close to a spherical shape, when the amorphous soft magnetic alloy powder is processed by an attritor or the like to produce a radio wave absorber. Since flattened particles having a uniform shape can be obtained and the particle size can be easily controlled, it is useful as a soft magnetic alloy powder for preparing a radio wave absorber.
[0064]
(Embodiment of flat amorphous soft magnetic alloy powder)
The flat amorphous soft magnetic alloy powder of the embodiment of the present invention is obtained by flattening the substantially spherical amorphous soft magnetic alloy powder of the embodiment having any one of the above configurations.
Here, as a method of flattening the amorphous soft magnetic alloy powder, for example, the substantially spherical amorphous soft magnetic alloy powder of the embodiment is put into an attritor and pulverized and mixed in a range of 10 minutes to 16 hours. Thus, an amorphous soft magnetic alloy powder mainly including the flattened amorphous soft magnetic alloy powder is obtained. The amorphous soft magnetic alloy powder before flattening is preferably not subjected to heat treatment.
[0065]
The pulverization and mixing by the attritor is preferably performed in the range of 10 minutes to 16 hours, and more preferably in the range of 4 to 8 hours.
If the time for pulverization and mixing is less than 10 minutes, the flattening is insufficient and the aspect ratio of the flat amorphous soft magnetic alloy powder tends to be 1 or more, for example, 10 or more. When it exceeds 16 hours, the aspect ratio of the flat amorphous soft magnetic alloy powder exceeds 80 or more. The flat amorphous soft magnetic alloy powder preferably has a thickness in the range of 0.1 to 5 μm (preferably 1 to 2 μm) and a major axis in the range of 1 to 80 μm (preferably 2 to 80 μm).
The obtained flat amorphous soft magnetic alloy powder may be heat-treated as necessary in the same manner as the above-described embodiment.
[0066]
The flat amorphous soft magnetic alloy powder of the present embodiment uses the substantially spherical amorphous soft magnetic alloy powder of the present embodiment with less surface irregularities, so it is amorphous when processed by an attritor or the like. The alloy powder is not crushed finely, can be flattened into a uniform shape, and flattened particles having a uniform shape can be obtained. When these flat amorphous soft magnetic alloy powders are mixed with an insulating material such as a resin to produce a radio wave absorber or the like, these powders are arranged in layers, so that they can be packed densely, The gap between can be reduced.
[0067]
(Embodiment of the powder core)
A dust core (a dust core) according to an embodiment of the present invention is a granulated product obtained by mixing a plurality or one of the substantially spherical amorphous soft magnetic alloy powders of the present embodiment, an insulating material, and a lubricant. The insulating material is used as a binder and solidified and molded. The substantially spherical amorphous soft magnetic alloy powder preferably has a specific resistance of 1.5 μΩ · m or more.
The shape of the dust core can be exemplified by an annular core 21 as shown in FIG. 2, for example, but the shape is not limited to this, and may be an oval or elliptical ring. Further, it may be substantially E-shaped in plan view, substantially U-shaped in plan view, or substantially I-shaped in plan view.
[0068]
The dust core is formed by binding the granulated powder with the insulating material, and a plurality of or a single amorphous soft magnetic alloy powder is present in the structure. The magnetic alloy powder is not dissolved to form a uniform structure. Moreover, it is preferable that each amorphous soft magnetic alloy powder in the granulated powder is insulated by an insulating material.
Thus, since the amorphous soft magnetic alloy powder and the insulating material are mixed and exist in the dust core 21, the specific resistance of the dust core itself is increased by the insulating material, and eddy current loss is reduced. Thus, the decrease in magnetic permeability in the high frequency region is reduced.
[0069]
Also, the temperature interval ΔT of the supercooled liquid of the amorphous soft magnetic alloy powder_xIs less than 20K, the internal stress is sufficiently relaxed without crystallizing during the heat treatment performed after compression molding the granulated powder prepared by mixing amorphous soft magnetic alloy powder, insulating material and lubricant. It becomes difficult to make.
[0070]
In particular, the dust core 21 of the present embodiment preferably has a coercive force of 80 A / m or less, more preferably 40 A / m or less, at an applied magnetic field of ± 2.4 kA / m.
[0071]
The insulating material constituting the dust core of the present embodiment increases the specific resistance of the dust core and can form a granulated powder containing amorphous soft magnetic alloy powder and binds the formed granulated powder. It is preferable to use a material that retains the shape of the dust core and does not cause a large loss in magnetic properties. For example, epoxy resin, silicone resin, silicone rubber, phenol resin, urea resin, melamine resin, PVA (polyvinyl alcohol) ) Liquid or powdered resin or rubber, water glass (Na₂O-SiO₂), Oxide glass powder (Na₂OB₂O₃-SiO₂, PbO-B₂O₃-SiO₂, PbO-BaO-SiO₂, Na₂OB₂O₃-ZnO, CaO-BaO-SiO₂, Al₂O₃-B₂O₃-SiO₂, B₂O₃-SiO₂), Glassy substance (SiO2) produced by the sol-gel method₂, Al₂O₃, ZrO₂TiO₂Etc.) and the like.
Various elastomers (rubbers) may be used as the insulating material.
In addition, a lubricant selected from stearates (zinc stearate, calcium stearate, barium stearate, magnesium stearate, aluminum stearate, etc.) is used simultaneously with the insulating material.
[0072]
Of these insulating materials, silicone resin or silicone rubber is particularly preferable.
Silicone rubber generally refers to a rubber-like elastic material composed of a crosslinked product of a linear organopolysiloxane having a high degree of polymerization. The high temperature type and the room temperature type are roughly classified according to the crosslinking method, but the room temperature type is preferred in the present invention. A room temperature type silicone rubber is obtained by reacting a linear polyorganosiloxane with a crosslinking agent such as a silane compound having an acetoxyl group, an alkoxyl group, an oxime group, an isopropenoxyl group, etc. Or the thing using the crosslinking agent which has an oxime group is preferable.
Silicone resin generally refers to a polymer of organopolysiloxane having an advanced three-dimensional network structure. It is produced by hydrolysis polycondensation of organochlorosilane or organoalkoxysilane or ring-opening polymerization of cyclic siloxane.
[0073]
Among the silicone rubbers described above, the silicone rubber obtained by crosslinking with a crosslinking agent having an alkoxyl group is less corrosive and can constitute a dust core having excellent corrosion resistance. Moreover, the silicone rubber obtained using the crosslinking agent containing the silane compound which has a normal butyl group in a molecule | numerator has the property which is especially excellent in elasticity.
Therefore, when the silicone rubber obtained by using a crosslinking agent containing a silane compound having a normal butyl group is used for the dust core of the present embodiment, the internal stress remaining in the amorphous soft magnetic alloy powder is small because the curing stress is small. And the soft magnetic properties of the amorphous soft magnetic alloy powder are improved. Thereby, the coercive force and core loss of a dust core can be reduced significantly.
[0074]
The particle size of the granulated powder used for the powder core 1 of this embodiment is preferably 45 μm or more and 500 μm or less, more preferably 45 μm or more and 300 μm or less, and even more preferably 45 μm or more and 150 μm or less for the reasons described above.
Further, the content of the granulated powder having a particle size of 45 μm or more and 500 μm or less is greater than 83% by weight of the total granulated powder constituting the powder core 1, or from the granulated powder having a particle size of less than 45 μm and a particle size of 500 μm. The content (mixing amount) of the larger granulated powder is 17% by weight or less of the total granulated powder, which can improve the fluidity when pouring the granulated powder into the mold for producing a compacted core, and mass production It is preferable at the point which can improve property, and it is more preferable that it is 15 weight% or less.
[0075]
Next, an example of the manufacturing method of the dust core of this embodiment will be described with reference to the drawings.
The method for producing a dust core according to the present invention comprises adding the substantially spherical amorphous soft magnetic alloy powder of the embodiment obtained by the water atomizing method, the insulating material and the lubricant, mixing and granulating the mixture. A step of forming a powder, a forming step of compression-molding the formed granulated powder to form a core precursor, and the core precursor (T_g-170) K or more (T_gAnd a heat treatment step of removing the internal stress of the core precursor by heat treatment at a temperature of K or lower.
[0076]
In the step of forming the granulated powder, the mixing ratio of the insulating material in the mixture of the amorphous soft magnetic alloy powder, the insulating material, and the lubricant may be 0.3 wt% or more and 5 wt% or less. It is preferably 1% by weight or more and 3% by weight or less.
If the mixing ratio of the insulating material is less than 0.3% by weight, the amorphous soft magnetic alloy powder and the lubricant cannot be formed into a predetermined shape together with the insulating material, which is not preferable. Moreover, when the mixing ratio exceeds 5% by weight, the addition density of the amorphous soft magnetic alloy powder in the granulated powder decreases, and the amorphous soft magnetic alloy powder in the powder core produced using the granulated powder This is not preferable because the content ratio of the powder core decreases and the soft magnetic properties of the dust core decrease.
[0077]
The mixing ratio of the lubricant in the mixture is preferably 0.1% by weight or more and 2% by weight or less, and more preferably 0.1% by weight or more and 1% by weight or less.
When the mixing ratio of the lubricant is less than 0.1% by weight, the flowability of the amorphous soft magnetic alloy powder cannot be improved so much, so that the improvement of the production efficiency of the granulated powder cannot be expected so much. The addition density of the amorphous soft magnetic alloy powder is lowered, and as a result, the soft magnetic properties of the dust core are lowered, which is not preferable. On the other hand, when the lubricant exceeds 2% by weight, the addition density of the amorphous soft magnetic alloy powder in the granulated powder is lowered, and the mechanical strength of the powder core is lowered, which is not preferable.
Once the granulated powder is formed, the formed granulated powder is classified, and the particle diameter is in the range of 45 μm to 500 μm, more preferably in the range of 45 μm to 300 μm, and still more preferably in the range of 45 μm to 150 μm. The range is selected and used in the subsequent process. For classification, a sieve, a vibrating sieve, a sonic sieve, an airflow classifier or the like can be used.
[0078]
Next, a molding step is performed in which the granulated powder is compression molded to form a magnetic core precursor.
Moreover, it is desirable to evaporate the solvent, moisture, etc. contained in the granulated powder before compression molding to form an insulating material layer on the surface of the amorphous soft magnetic alloy powder.
[0079]
Next, the granulated powder is compression-molded to produce a magnetic core precursor. For the production of the core precursor, a mold 110 as shown in FIG. 3 is used. The mold 110 includes a hollow cylindrical die 111, and an upper punch 112 and a lower punch 113 inserted into the hollow portion 111a of the die 111.
A cylindrical protrusion 112 a is provided on the lower surface of the upper punch 112, and the upper punch 112, the lower punch 113, and the die 111 are integrated to form an annular mold inside the mold 110. And this metal mold | die 110 is filled with the above-mentioned granulated powder.
[0080]
Next, the granulated powder filled in the mold 110 is compression-molded by heating to room temperature or a predetermined temperature while applying uniaxial pressure.
FIG. 4 shows a main part of an example of a discharge plasma sintering apparatus suitable for use in compression molding. The discharge plasma sintering apparatus of this example supports a mold 110 filled with a mixture, a punch electrode 114 that supports a lower punch 113 of the mold 110 and serves as one electrode when a pulse current described later is passed, and a mold 110. The upper punch 112 is pressed downward, and the punch electrode 115 serving as the other electrode for passing a pulse current and the thermocouple 17 for measuring the temperature of the granulated powder in the mold 110 are mainly constituted.
The discharge plasma sintering apparatus is housed in a chamber 118. The chamber 118 is connected to a vacuum exhaust apparatus and an atmospheric gas supply apparatus (not shown), and is granulated to fill the mold 110. The powder can be held in a desired atmosphere such as an inert gas atmosphere.
Although the energizing device is omitted in FIG. 4, a separately provided energizing device is connected to the upper and lower punches 112 and 113 and the punch electrodes 114 and 115, and a pulse current is supplied from this energizing device to the punches 112, 113 and It is comprised so that electricity can be supplied through the punch electrodes 114 and 115.
[0081]
Then, the mold 110 filled with the granulated powder is placed in a discharge plasma sintering apparatus, the inside of the chamber 118 is evacuated, and simultaneously, the uniaxial pressure P is applied to the mixture from above and below by the punches 112 and 113. Then, the granulated powder is compression-molded while applying a pulse current.
In this discharge plasma sintering process, the granulated powder can be quickly heated at a predetermined speed by an energizing current, and the compression molding time can be shortened. It is suitable for compression molding while maintaining the quality phase.
[0082]
In the present invention, the temperature at which the above granulated powder is compression-molded varies depending on the type of insulating material and the composition of the amorphous soft magnetic alloy powder. Fe_74.43Cr_1.96P_9.04C_2.16B_7.54Si_4.87In the case of using a composition having the composition, it is necessary to set the temperature to 373 K (100 ° C.) or more in order to bind the granulated powders with the insulating material. In order not to emit, it is necessary to set it as 673K (400 degreeC) or less. When the insulating material oozes out, the content of the insulating material in the dust core decreases, the specific resistance of the dust core decreases, and the magnetic permeability in the high frequency band decreases.
If the granulated powder is compression molded in a temperature range of 373 K (100 ° C.) or more and 673 K (400 ° C.) or less, the insulating material is appropriately cured. Therefore, the granulated powder can be bound and formed into a predetermined shape. it can.
[0083]
As for the uniaxial pressure P applied to the granulated powder during compression molding, if the pressure is too low, the density of the dust core cannot be increased, and a dense dust core cannot be formed. If the pressure is too high, the insulating material oozes out, the content of the insulating material in the dust core decreases, the specific resistance of the dust core decreases, and the magnetic permeability in the high frequency band decreases. Accordingly, the uniaxial pressure P varies depending on the type of insulating material and the composition of the amorphous soft magnetic alloy powder, but water glass as the insulating material and Fe as the amorphous soft magnetic alloy powder._74.43Cr_1.96P_9.04C_2.16B_7.54Si_4.87In the case of using a composition having such a composition, it is preferably 600 MPa or more and 1500 MPa or less, and more preferably 600 MPa or more and 900 MPa or less.
In this way, an annular magnetic core precursor is obtained.
When the granulated powder filled in the mold 110 is compression-molded at room temperature while applying a uniaxial pressure, a press having the same configuration as the apparatus shown in FIG. 4 except that the energizing apparatus is not connected. An annular magnetic core precursor can also be produced using the apparatus.
[0084]
When silicone rubber is used as the insulating material, the core precursor having a predetermined shape can be obtained by compression-molding the granulated particles at room temperature in the molding step.
[0085]
Further, since silicone rubber has elasticity, the curing stress is small and the internal stress remaining in the amorphous soft magnetic alloy powder is small. For this reason, the influence of magnetostriction is removed and the soft magnetic properties of the amorphous soft magnetic alloy powder are improved. Thereby, the coercive force and core loss of a dust core can be reduced significantly.
In particular, as described above, a silicone rubber obtained by using a cross-linking agent containing a silane compound having a normal butyl group in the molecule is particularly excellent in elasticity. The residual internal stress becomes extremely small, the soft magnetic properties of the amorphous soft magnetic alloy powder are further improved, and the coercive force and core loss of the dust core can be further greatly reduced.
[0086]
When silicone rubber is used, the pressure applied to the granulated powder at the time of compression molding is too low to increase the density of the dust core, making it impossible to form a dense dust core. . On the other hand, if the pressure is too high, the die and punch are consumed very much, and a long-time heat treatment is required to remove the stress generated during molding. Therefore, although the pressure varies depending on the composition of the amorphous soft magnetic alloy powder,_74.43Cr_1.96P_9.04C_2.16B_7.54Si_4.87In the case of using the composition having the composition, it is preferably 500 MPa or more and 2500 MPa or less, and more preferably 1000 MPa or more and 2000 MPa or less.
[0087]
In particular, as the amorphous soft magnetic alloy powder contained in the granulated powder constituting the powder core, the average particle diameter (D₅₀) Is larger than 4 μm and not larger than 45 μm, and the tap density is 3.7 Mg / m.³The specific surface area is 0.3m²/ G or less and an oxygen concentration of 3000 ppm or less, the core loss (W) when measured under conditions of a frequency of 100 kHz and a magnetic flux density of 0.1 T is 450 kW / m.³It can be reduced to the following, and can be significantly reduced from the core loss of the conventional dust core. Further, the real part μ ′ of the complex permeability up to the frequency of 1 MHz can be made almost constant as 57-80, and the DC bias magnetic field 5500 Am^-1DC superposition characteristics (μ ′_DC5500) Can be made substantially constant between 30 and 34.5, and is easy to use when used in a magnetic core.
Further, as the amorphous soft magnetic alloy powder, an average particle diameter (D₅₀) Is larger than 4 μm and not larger than 16 μm, and the tap density is 4.0 Mg / m.³The specific surface area is 0.23m²/ G or less and an oxygen concentration of 2000 ppm or less, the core loss (W) when measured under conditions of a frequency of 100 kHz and a magnetic flux density of 0.1 T is 250 kW / m.³You can: In addition, the real part μ ′ of the complex permeability up to a frequency of 1 MHz can be made almost constant as 57 to 75, and the DC bias magnetic field 5500 Am.^-1DC superposition characteristics (μ ′_DC5500) Can be made substantially constant at 30 to 36, and therefore, preferable characteristics can be provided when used in a magnetic core.
[0088]
Next, a heat treatment step is performed in which the core precursor is heat treated to remove internal stress of the core precursor. When the core precursor is heat-treated within a predetermined temperature range, the internal stress of the core precursor itself generated in the powder manufacturing process and the molding process and the internal stress of the amorphous soft magnetic alloy powder contained in the core precursor are removed. And a dust core having a low coercive force can be produced.
The temperature of the heat treatment is (T_g-170) K or more (T_g) K or less is preferred, and (T_g-160) K or more (T_g-5) A range of K or less is more preferable, and (T_g-140) K or more (T_g−10) The range of K or less is more preferable, and (T_g-110) K or more (T_g-10) The range of K or less is most preferable.
[0089]
Core precursor (T_g-160) K or more (T_g-5) When heat treatment is performed in a temperature range of K or less, for example, a dust core having a coercive force of 100 A / m or less at an applied magnetic field of ± 2.4 kA / m can be produced (T_g-140) K or more (T_g-10) When heat treatment is performed at a temperature of K or less, for example, a dust core having a coercive force of 80 A / m or less at an applied magnetic field of ± 2.4 kA / m can be obtained._g-110) K or more (T_g-10) When the heat treatment is performed at a temperature of K or less, for example, a dust core having a coercive force of 40 A / m or less in an applied magnetic field ± 2.4 kA / m can be obtained.
[0090]
Heat treatment temperature is (T_gIf it is less than -170) K, the internal stress of the core precursor cannot be sufficiently removed, which is not preferable._g) If K is exceeded, the amorphous soft magnetic alloy powder is crystallized and the coercive force is increased, which is not preferable.
[0091]
For example, Fe_74.43Cr_1.96P_9.04C_2.16B_7.54Si_4.87In the case of an amorphous soft magnetic alloy powder of the composition_gIs 780K, and the heat treatment temperature is preferably in the range of 610K (337 ° C) to 780K (507 ° C), more preferably in the range of 620K (347 ° C) to 775K (502 ° C), and 640K (367 ° C) to 770K (497 ° C), more preferably 670K (397 ° C) to 770K (497 ° C).
[0092]
In particular, when silicone rubber is used as the insulating material, the heat treatment temperature is preferably in the range of 670 K (397 ° C.) to 770 K (497 ° C.). When silicone rubber is used, if the heat treatment temperature is less than 670K, the internal stress of the core precursor cannot be sufficiently removed, which is not preferable. If the heat treatment temperature exceeds 773K, the silicone rubber is excessively decomposed, This is not preferable because the strength of the dust core decreases.
When silicone rubber is used as the insulating material, the heat treatment atmosphere is preferably a vacuum atmosphere or an inert gas atmosphere such as nitrogen gas or argon gas, and more preferably a nitrogen gas atmosphere.
By performing the heat treatment in this manner, the annular powder core 21 of the present embodiment is obtained.
[0093]
The powder core 21 thus obtained contains the amorphous soft magnetic alloy powder of the present embodiment, and thus has excellent soft magnetic properties at room temperature, and better soft magnetic properties by heat treatment. Show.
For this reason, this dust core can be applied as a magnetic core of various magnetic elements as a material having excellent soft magnetic properties, and a magnetic core having superior soft magnetic properties compared to conventional materials can be obtained.
[0094]
In the above description, the granulated powder is compression-molded by a discharge plasma sintering apparatus. However, the present invention is not limited to this, and compression molding is performed by a normal powder molding method, a hot press method, an extrusion method, or the like. The powder core of the present invention can also be obtained.
[0095]
In the above description, the method of manufacturing an annular powder core using a mold has been described. However, the present invention is not limited thereto, and a bulk-shaped formed body is manufactured and cut into an annular shape. You may manufacture the powder core of various shapes by cutting out in shapes, such as a rod shape, planar view substantially E shape, and planar view substantially U shape.
[0096]
According to the dust core of the embodiment, the amorphous soft magnetic alloy powder of the present embodiment, which has excellent soft magnetic properties, has a high bulk density, has few surface irregularities, and is formed in a substantially spherical shape, is used. Since the produced granulated powder is solidified and molded, the molding density of the powder core can be increased, insulation between the powders can be maintained, and magnetic characteristics can be improved. Moreover, since the amorphous soft magnetic alloy powder of this embodiment manufactured by the water atomization method is used, mass productivity can be improved.
Also, instead of adding a lubricant after granulated powder production, by adding a lubricant at the granulated powder production stage, the slip between amorphous soft magnetic alloy powders when producing granulated powder is good, The production efficiency of the granulated powder can be improved, and since the amorphous soft magnetic alloy powder can be densely contained in the granulated powder, the density of the granulated powder is improved. A powder core is obtained.
[0097]
In addition, since the amorphous soft magnetic alloy powder obtained by the water atomization method has a small average particle size and is composed of substantially spherical particles, when this amorphous soft magnetic alloy powder is used for a dust core, saturation magnetization is obtained. Thus, it is possible to obtain a dust core having a high core loss, a low core loss, and an excellent magnetic permeability change rate (amplitude magnetic permeability) with respect to the applied magnetic field change and an inductance change rate (DC superposition characteristic) with respect to the applied magnetic field change.
In addition, as a compacting core using the granulated powder of this embodiment, not only the shape mentioned above but the J-shaped compacting core 41 as shown in FIG. 6 or a circle as shown in FIG. The dust core 51 having a groove with a notch formed in a part of the ring is also a dust core of the present invention. The manufacturing method of these dust cores 41 and 51 can be manufactured by compression molding in the same manner as the manufacturing method of the dust core 21 of the above-described embodiment except that the mold shape is different, or bulk molding It can also be manufactured by forming a body and cutting it. In these dust cores 41 and 51, the same effect as the dust core 21 of the embodiment described above can be obtained.
In particular, the J-shaped dust core 41 can be suitably used as a coil magnetic core provided in an electromagnetic induction heater (IH heater). As a schematic configuration of such an IH type heater, for example, a coil is disposed under a pot (object to be heated), and a J-shaped dust core 41 is disposed under the coil. In the IH type heater, the kettle is heated by the coil, but the IH type heater with improved heat generation efficiency is provided by providing the J-shaped dust core 41 of the present embodiment with a small core loss as the coil core. realizable.
[0098]
(Embodiment of radio wave absorber)
The radio wave absorber of the embodiment of the present invention is obtained by mixing the flat amorphous soft magnetic alloy powder of the present embodiment and an insulating material. The plurality of flat amorphous soft magnetic alloy powders added to the radio wave absorber are arranged in layers in the insulating material.
As the insulating material used here, a material that doubles as an insulating property and a binder is used, and a thermoplastic resin such as vinyl chloride, polypropylene, ABS resin, phenol resin, chlorinated polyethylene, silicon resin, or silicon rubber is selected. Among these thermoplastic resins, chlorinated polyethylene is particularly preferable from the viewpoint of processability.
This type of chlorinated polyethylene exhibits characteristics that can be considered as intermediate between polyethylene and polyvinyl chloride, and the chlorine content is, for example, 30 to 45%, the elongation is, for example, 420 to 800%, and the Mooney viscosity is 35. Those having characteristics such as ˜75 (Ms1 + 4: 100 ° C.) can be used.
In another form of the radio wave absorber of the present invention, at least the flat amorphous soft magnetic alloy powder of the present embodiment and a binder composed of a silicone elastomer are mixed and solidified into a sheet shape. It has been made.
Further, in addition to the flat amorphous soft magnetic alloy powder of the present embodiment and the resin as the binder, a lubricant composed of aluminum stearate may be added to the previous wave absorber, Furthermore, a silane coupling agent may be added.
[0099]
In the previous wave absorber, the flat amorphous soft magnetic alloy powder of the present embodiment is solidified with a resin as a binder, so the flat amorphous soft magnetic alloy powder of the present embodiment is The structure is dispersed inside the resin and arranged in layers in the resin.
Further, the other wave absorber is formed by solidifying and molding the flat amorphous soft magnetic alloy powder of the present embodiment together with a binder made of a silicone elastomer, and the flat amorphous material of the present embodiment. The soft magnetic alloy powder is dispersed and arranged in a layered manner in the binder, and it is particularly preferable that each flat amorphous soft magnetic alloy powder is insulated by a silicone elastomer.
As described above, since the flat amorphous soft magnetic alloy powder of this embodiment is insulated by the resin binder, the impedance of the radio wave absorber itself is increased, thereby suppressing the generation of eddy currents. The imaginary part μ ″ of complex permeability in the frequency band of several hundred MHz to several GHz (hereinafter referred to as “imaginary permeability μ”) can be increased in a wide range, and the electromagnetic wave suppression effect in the high frequency band can be improved. Can do.
[0100]
In the above radio wave absorber, a material using a thermoplastic resin as a binder has an imaginary permeability μ ″ at 1 GHz of 6 or more. When the imaginary permeability μ ″ is 6 or more, the GHz band This is preferable because the electromagnetic wave suppression effect at the top is improved and high-frequency radio waves can be effectively shielded. In addition, by selecting a soft binder, it is possible to obtain a soft wave absorber, such as a plate gum, which can be deformed freely with fingertip force. . For example, it has characteristics that are far more flexible and deformable than those using the aforementioned silicone elastomer as a binder.
In addition, in the above-described radio wave absorber, those using a silicone elastomer as a binder can obtain a imaginary permeability μ ″ at 1 GHz of 10 or more. The imaginary permeability μ ″ is 10 or more. It is preferable because the electromagnetic wave suppression effect in the GHz band is improved and high-frequency radio waves can be effectively shielded.
[0101]
Silicone elastomer and chlorinated polyethylene not only increase the impedance of the wave absorber, but also hold the shape of the wave absorber by binding the flat amorphous soft magnetic alloy powder of this embodiment. Moreover, since the silicone elastomer is excellent in compression moldability, a high-strength radio wave absorber can be formed even when solidified at room temperature. Furthermore, silicone elastomer and chlorinated polyethylene exhibit sufficient elasticity even inside the radio wave absorber, for example 1 × 10^-6~ 50x10^-6Even when an amorphous soft magnetic alloy powder having a magnetostriction constant of 1 is used, the strain can be relaxed, the internal stress of the radio wave absorber can be relaxed, and the imaginary permeability μ ″ can be increased.
[0102]
Note that when a lubricant made of aluminum stearate is added to the above-described resin, the flat amorphous soft magnetic alloy powder of the present embodiment is densely filled and the density of the radio wave absorber is improved. This increases the imaginary permeability μ ″.
Further, when a silane coupling agent is added to the above-described resin, the flat amorphous soft magnetic alloy powder of this embodiment and the silicone elastomer are strongly bonded by the silane coupling agent, and the flat amorphous soft magnetic alloy powder The silicone elastomer is uniformly coated on the surface of the substrate. As a result, the insulation between the flat amorphous soft magnetic alloy powders is enhanced and the imaginary permeability μ ″ is improved.
[0103]
In the radio wave absorber of this embodiment, since the flat amorphous soft magnetic alloy powder of this embodiment is arranged in layers in the insulating material, it can be closely packed in the radio wave absorber and between the flattened powders. In addition, the flattened powder has a larger aspect ratio than the amorphous soft magnetic alloy powder that remains substantially spherical, the impedance of the radio wave absorber itself increases, and eddy currents are generated. It is suppressed. Specifically, if the aspect ratio of the flat amorphous soft magnetic alloy powder is 1 or more, the contact between particles is reduced, the impedance of the radio wave absorber itself is increased, and the generation of eddy current is suppressed. The imaginary permeability μ ″ in the GHz band tends to be 6 or more, thereby improving the electromagnetic wave suppressing effect of the radio wave absorber.
If the aspect ratio of the flat amorphous soft magnetic alloy powder is 10 or more, the contact between the particles is further reduced, the rate of increase in the impedance of the radio wave absorber itself is increased, and the generation of eddy current is suppressed. The imaginary permeability μ ″ in the GHz band tends to be 10 or more, thereby improving the electromagnetic wave suppressing effect of the radio wave absorber.
The upper limit of the aspect ratio is preferably 800 or less. When the aspect ratio is 800 or less, the demagnetizing field of the flat amorphous soft magnetic alloy powder itself does not become excessive, and the real part μ ′ of the complex permeability in the low frequency band (hereinafter referred to as effective permeability μ ′). ) Is suppressed to a low level, and in contrast, the imaginary permeability μ ″ is likely to be 6 or more, and the electromagnetic wave suppression effect is improved.
The upper limit of the aspect ratio is more preferably 300 or less. If the aspect ratio is 300 or less, the demagnetizing field of the flattened particle itself is not excessively small, and the real part μ ′ of the complex permeability in the low frequency band (hereinafter referred to as effective permeability μ ′) is suppressed to a lower level. In contrast, the imaginary permeability μ ″ is likely to be 10 or more, and the electromagnetic wave suppression effect is further improved.
[0104]
The density of the wave absorber of this embodiment is 3.0 g / cm³The above is preferable. Density is 3.0g / cm³When the above is satisfied, the flat amorphous soft magnetic alloy powder is densely packed and the gaps between the flat particles are reduced. As a result, the imaginary permeability μ ″ in the GHz band tends to be 10 or more, and the electromagnetic wave suppressing effect is obtained. improves.
The higher the density of the radio wave absorber, the better. However, if the density is too high, the flat particles are packed too densely, the impedance of the radio wave absorber is reduced, eddy currents are generated, and the imaginary permeability μ ″ is lowered. The upper limit of the density of the absorber is 6.5 g / cm³It is preferable to set the following.
[0105]
The content of the flat amorphous soft magnetic alloy powder in the radio wave absorber of the present embodiment is preferably 30% by volume to 80% by volume. When the content of the flat amorphous soft magnetic alloy powder is 30% by volume or more, the amount of the magnetic material is sufficient, and the electromagnetic wave suppressing effect can be effectively exhibited. Further, if the content is 80% by volume or less, the alloy powders do not come into contact with each other and the impedance does not decrease, and the imaginary permeability μ ″ can be reliably maintained high and the electromagnetic wave suppressing effect can be effectively exhibited. .
The content of the silicone elastomer or chlorinated polyethylene is the remainder excluding the flat amorphous soft magnetic alloy powder.
[0106]
When the lubricant is added, it is preferably added in the range of 0.1% by weight to 5% by weight with respect to the radio wave absorber. Moreover, when adding a silane coupling agent, it is preferable to add in 0.1 to 2 weight% with respect to an electromagnetic wave absorber.
[0107]
According to the radio wave absorber of the present embodiment, the flattened amorphous soft magnetic alloy powder obtained by flattening the substantially spherical amorphous soft magnetic alloy powder exhibiting excellent soft magnetic characteristics is used. Since the insulating material can be densely packed, it is possible to improve the electromagnetic wave suppression effect in the frequency band of several hundred MHz to several GHz.
The radio wave absorber of the present embodiment is insulated from the flattened amorphous soft magnetic alloy powder produced by flattening the substantially spherical amorphous soft magnetic alloy powder of the present embodiment manufactured by the water atomization method. Since it is obtained by mixing with the material, mass productivity is excellent.
The flat amorphous soft magnetic alloy powder described above may be coated with water glass. When the flattened particles are coated with water glass, the insulation between the particles is further improved, the impedance of the radio wave absorber is further improved, and the imaginary permeability μ ″ in the high frequency band can be further increased, thereby suppressing the electromagnetic wave. Can be improved.
[0108]
The amorphous soft magnetic alloy powder used in the radio wave absorber of the present embodiment may mainly contain the flat amorphous soft magnetic alloy powder of the present embodiment. The spherical amorphous soft magnetic alloy powder of this embodiment may be used in place of the flat amorphous soft magnetic alloy powder. Also, the flat amorphous soft magnetic alloy powder of this embodiment and the spherical non-crystalline soft magnetic alloy powder may be used. It may be a mixture of crystalline soft magnetic alloy powder.
[0109]
【Example】
[Experimental example 1: FeCrPCB alloy]
Fe, Fe-C alloy, Fe-P alloy, B and Cr are weighed in predetermined amounts as raw materials, and these raw materials are put in a molten crucible of the high-pressure water spray apparatus shown in FIG. The molten alloy is dropped from the molten metal nozzle of the molten crucible, high pressure water is sprayed from the water spray nozzle of the water sprayer shown in FIG. 1 to make the molten alloy mist, and the molten mist is quenched in the chamber and softened. When producing magnetic alloy powder, manufacturing conditions were changed and various soft magnetic alloy powders (No. 1 to 3 soft magnetic alloy powders) were produced.
[0110]
The composition of the various soft magnetic alloy powders obtained is Fe₇₅Cr₂P₁₃C₅B₅It was the composition which becomes.
In addition, the above Fe₇₅Cr₂P₁₃C₅B₅As a result of analysis of the structure of various soft magnetic alloy powders having the following composition by the X-ray diffraction method, the X-ray diffraction pattern of each alloy powder shows a broad pattern. It turns out that it is composed. Therefore, it can be seen that even an alloy composed of Fe, Cr, P, C, and B can form an amorphous soft magnetic alloy powder composed of an amorphous phase.
In addition, the above Fe₇₅Cr₂P₁₃C₅B₅Various soft magnetic alloy powders having the composition described above were observed with a scanning electron microscope (SEM) to examine the shape. The results are shown in Table 1.
The average particle size of the obtained soft magnetic alloy powder (D₅₀Table 1 shows the results of examining the minimum value, maximum value, and average value of the tap density, specific surface area, oxygen concentration, and aspect ratio.
[0111]
Furthermore, DSC measurement (Differential scanning caloriemetry) of various soft magnetic alloy powders obtained is performed to measure glass transition temperature Tg, crystallization start temperature Tx, Curie temperature Tc and melting point Tm. The temperature intervals ΔTx and Tg / Tm of the cooling liquid were determined. These results are shown in Table 2. In addition, the temperature increase rate at the time of DSC measurement was 0.67 K / sec. In Table 2, Tm * indicates the melting temperature of the alloy.
Further, the saturation magnetization σs of the obtained various soft magnetic alloy powders was measured with a vibrating sample magnetometer (VSM). These results are also shown in Table 2.
[0112]
Next, with respect to 98.3 wt% of the obtained soft magnetic alloy powder, 1.4 wt% of a silicone resin as an insulating material and 0.3 wt% of zinc stearate as a lubricant were mixed and granulated. A granulated powder was obtained. These granulated powders were dried in the atmosphere at room temperature for 12 hours. Next, the dried granulated powder was classified, and a powder having a particle size in the range of 45 μm to 500 μm was selected and used in the subsequent step.
After a granulated powder having a particle size of 45 μm or more and 500 μm or less is filled in a WC mold shown in FIG. 3, using a press apparatus as shown in FIG. 4 with upper and lower punches 112 and 113 at atmospheric pressure and room temperature. The granulated powder was pressurized to a molding pressure (Ps) of 2000 MPa.
And heat treatment temperature T_aWere heat-treated at 573 K (300 ° C.) to 723 K (450 ° C.) for 3600 seconds to produce various powder cores. The shape of the dust core was an annular shape having an outer diameter of 20 mm, an inner diameter of 12 mm, and a thickness of 7 mm.
The core loss (W) of the various powder cores obtained was measured. The core loss here is measured when the frequency is 100 kHz and the magnetic flux density is 0.1 T. The results are also shown in Table 2.
Further, the real part of the complex permeability (also referred to as effective permeability) μ ′ and DC superimposition characteristics (μ ′) of the various powder cores obtained._DC5500 ) Was measured. Here, μ ′ is measured at a frequency of 1 kHz, and μ ′_DC5500Is DC bias magnetic field 5500 Am^-1The effective permeability at this time is measured. The results are also shown in Table 2.
[0113]
[Table 1]

[0114]
[Table 2]

[0115]
From the results shown in Tables 1 and 2, No. The soft magnetic alloy powders of 1 to 2 were obtained in an irregular shape, and the average aspect ratio, D₅₀It can be seen that the specific surface area and oxygen concentration are large and the tap density is small. Such no. It can be seen that the dust core produced using 1-2 soft magnetic alloy powders has a large core loss and a low direct current superposition characteristic. No. Since the soft magnetic alloy powders 1 and 2 have a high oxygen concentration, the thermal stability is considered to change.
In contrast, no. The soft magnetic alloy powder No. 3 has a substantially spherical shape, has a small specific surface area and oxygen concentration, a large tap density, and a No. 3 soft magnetic alloy powder. It can be seen that the saturation magnetization .sigma.s is also higher than those of 1-2. This No. No. 3 soft magnetic alloy powder was used to produce a compact core. It can be seen that the core loss can be greatly reduced and the DC superposition characteristics are improved as compared with the dust core produced using the soft magnetic alloy powders 1 and 2.
In Experimental Example 1, Fe₇₅Cr₂P₁₃C₅B₅The average particle size (D₅₀) Was 9.0 μm or more, it was found that the structure crystallized.
[0116]
(Experimental example 2)
Fe, Fe-C alloy, Fe-P alloy, Cr, B or B and Si are weighed in predetermined amounts, respectively, and these raw materials are put in the molten crucible of the high-pressure water spray device shown in FIG. The molten alloy is dropped from the molten metal crucible melt nozzle and high pressure water is sprayed from the water spray nozzle of the water sprayer shown in FIG. 1 to make the molten alloy mist. When producing the soft magnetic alloy powder by quenching, various soft magnetic alloy powders (No. 4 to 14 soft magnetic alloy powders) were produced by changing the production conditions.
[0117]
The composition of the obtained soft magnetic alloy powder is Fe_100-t-yz-w-xP_ySi_tC_zB_wCr_x(Wherein z is 1.2 to 7 atomic%, w is 5.6 to 8.7 atomic%, x is 1.96 atomic% to 2 atomic%, and y is 8.44 to 12.74 atomic%. , T was 0 to 4.87 atomic%). Note that v in the composition formula represents a composition ratio of P or a total composition ratio of P and Si.
In addition, the above Fe_100-t-yz-w-xP_ySi_tC_zB_wCr_xAs a result of analysis of the structure of various soft magnetic alloy powders having the following composition by the X-ray diffraction method, the X-ray diffraction pattern of each alloy powder shows a broad pattern. It turns out that it is composed. Therefore, it can be seen that an amorphous soft magnetic alloy powder composed of an amorphous phase can be formed even with an alloy composed of Fe, Cr, P, C, B or B and Si.
In addition, the above Fe_{100-y (-t) -zw-x}(P_yOr P_ySi_t) C_zB_wCr_xVarious soft magnetic alloy powders having the composition described above were observed with a scanning electron microscope (SEM) to examine the shape. The results are shown in Table 3.
The average particle size of the obtained soft magnetic alloy powder (D₅₀Table 3 shows the results of examining the minimum value, maximum value, and average value of the tap density, specific surface area, oxygen concentration, and aspect ratio.
[0118]
Furthermore, DSC measurement (Differential scanning caloriemetry) of the obtained various soft magnetic alloy powders is performed to measure the glass transition temperature Tg, the crystallization start temperature Tx, the Curie temperature Tc, and the melting point Tm. The temperature intervals ΔTx and Tg / Tm of the cooling liquid were determined. These results are shown in Table 4. In addition, the temperature increase rate at the time of DSC measurement was 0.67 K / sec. In Table 4, Tm * indicates the melting temperature of the alloy.
Further, the saturation magnetization σs of the various soft magnetic alloy powders obtained was measured in the same manner as in Experimental Example 1. These results are shown together in Table 4.
[0119]
Next, a granulated powder was prepared in the same manner as in Experimental Example 1 except that the soft magnetic alloy powder obtained in Experimental Example 2 was used, and further, in the same manner as in Experimental Example 1 using these granulated powders. Various powder cores were manufactured.
The core loss (W) of the various powder cores obtained was measured in the same manner as in Experimental Example 1. The results are also shown in Table 4.
Further, the effective permeability (μ ′) and DC superposition characteristics (μ ′) of the various powder cores obtained._DC5500 ) Was measured in the same manner as in Experimental Example 1. The results are also shown in Table 4.
[0120]
[Table 3]

[0121]
[Table 4]

[0122]
From the results shown in Tables 3 and 4, No. It can be seen that the 4-12 soft magnetic alloy powders are substantially spherical.
No. It can be seen that the soft magnetic alloy powders 4 and 9 have a total composition ratio v of P and Si exceeding 15 atomic% and ΔTx is 46K or less.
On the other hand, when the composition ratio of P or the total composition ratio v of P and Si is 15 atomic% or less, No. In soft magnetic alloy powders of 5 to 8, ΔTx can be made larger when both P and Si are added than when P is added alone, and when both P and Si are added, the composition ratio It can be seen that the larger v is, the larger ΔTx can be and the amorphous phase forming ability can be improved. In Experimental Example 2, Fe_70.85Cr₂P_12.29C_4.65B₇Si_3.32The average particle size (D₅₀) Was 9.0 μm or more, it was found that the structure crystallized.
[0123]
No. In soft magnetic alloy powders of 10 to 12, it can be seen that ΔTx can be increased as the amount of Si added is increased, and the amorphous phase forming ability can be improved.
Next, no. The soft magnetic alloy powder of No. 13 was obtained in an irregular shape, and the average aspect ratio, D₅₀It can be seen that the specific surface area and oxygen concentration are large and the tap density is small. Such no. It can be seen that the dust core produced using the No. 13 soft magnetic alloy powder has a large core loss and poor DC superposition characteristics. No. Since the soft magnetic alloy powder No. 13 has a high oxygen concentration, it is considered that the thermal stability changes.
In contrast, no. The soft magnetic alloy powder No. 14 has a substantially spherical shape, has a small specific surface area and oxygen concentration, a large tap density, and a No. 14 soft magnetic alloy powder. It can be seen that the saturation magnetization .sigma. This No. No. 14 soft magnetic alloy powder was used to produce a compact core. It can be seen that the core loss can be greatly reduced and the DC superposition characteristics are excellent as compared with the dust core produced using 13 soft magnetic alloy powders.
[0124]
(Experimental example 3)
Fe, Fe-C alloy, Fe-P alloy, B, Si, Cr are weighed in predetermined amounts as raw materials, and these raw materials are put in a molten crucible of the high-pressure water spray device shown in FIG. Then, the molten alloy is dropped from the molten metal nozzle of the molten crucible and high pressure water is sprayed from the water spray nozzle of the water sprayer shown in FIG. 1 to atomize the molten alloy, and the molten molten alloy is rapidly cooled in the chamber. When producing the soft magnetic alloy powder, the production conditions were changed to produce various soft magnetic alloy powders (No. 15 to 21 soft magnetic alloy powders). In addition, No. The soft magnetic alloy powder No. 17 was left at room temperature for a long time after the powder formation.
[0125]
The composition of the obtained soft magnetic alloy powder is Fe₇₈P_9.23C_2.2B_7.7Si_2.87Or Fe_100-t-yz-w-xP_ySi_tC_zB_wCr_x(Wherein z is 2.16 to 2.2 atomic%, w is 7.54 to 7.7 atomic%, x is 1 atomic% to 8 atomic%, and y is 9.04 to 9.23 atomic%. , T was 2.87 to 4.87 atomic%, and v was 12.1 to 13.91 atomic%). Note that v in the composition formula represents the total composition ratio of P and Si.
In addition, the above Fe₇₈P_9.23C_2.2B_7.7Si_2.87Or Fe_100-t-yz-w-xP_ySi_tC_zB_wCr_xAs a result of analysis of the structure of various soft magnetic alloy powders having the following composition by the X-ray diffraction method, the X-ray diffraction pattern of each alloy powder shows a broad pattern. It turns out that it is composed. Therefore, it can be seen that even an alloy made of Fe, Cr or Al, P, C, B, Si can form an amorphous soft magnetic alloy powder made of an amorphous phase.
Fe₇₈P_9.23C_2.2B_7.7Si_2.87Or Fe_100-t-yz-w-xP_ySi_tC_zB_wCr_xVarious soft magnetic alloy powders having the composition described above were observed with a scanning electron microscope (SEM) to examine the shape. The results are shown in Table 5.
The average particle size of the obtained soft magnetic alloy powder (D₅₀Table 5 shows the results of examining the minimum value, maximum value, and average value of the tap density, specific surface area, oxygen concentration, and aspect ratio.
[0126]
Furthermore, DSC measurement (Differential scanning caloriemetry) of various soft magnetic alloy powders obtained is performed to measure glass transition temperature Tg, crystallization start temperature Tx, Curie temperature Tc and melting point Tm. The temperature intervals ΔTx and Tg / Tm of the cooling liquid were determined. These results are shown in Table 6. In addition, the temperature increase rate at the time of DSC measurement was 0.67 K / sec. In Table 6, Tm * indicates the melting temperature of the alloy.
Further, the saturation magnetization σs of the various soft magnetic alloy powders obtained was measured in the same manner as in Experimental Example 1. These results are also shown in Table 6.
[0127]
Next, a granulated powder was prepared in the same manner as in Experimental Example 1 except that the soft magnetic alloy powder obtained in Experimental Example 3 was used, and further, in the same manner as in Experimental Example 1 using these granulated powders. Various powder cores were manufactured.
The core loss (W) of the various powder cores obtained was measured in the same manner as in Experimental Example 1. The results are also shown in Table 6.
Further, the effective permeability (μ ′) and DC superposition characteristics (μ ′) of the various powder cores obtained._DC5500 ) Was measured in the same manner as in Experimental Example 1. The results are also shown in Table 6.
[0128]
[Table 5]

[0129]
[Table 6]

[0130]
From the results shown in Tables 5 and 6, No. It can be seen that the 15-21 soft magnetic alloy powders are substantially spherical.
However, no. It can be seen that the soft magnetic alloy powder No. 15 has a high oxygen concentration, rust is generated, and the corrosion resistance is poor. No. No. 17 soft magnetic alloy powder has a large oxygen concentration and an average particle size (D₅₀) Is small, and it can be seen that the core loss produced using this alloy powder has a large core loss.
In addition, the addition amount of Cr is 1 to 4 atomic% No. No. 16, 18-20 soft magnetic alloy powders No. 8 with 8 atomic% of Cr added. It can be seen that the saturation magnetization is larger than that of the 21 soft magnetic alloy powder. No. The reason why the saturation magnetization of the soft magnetic alloy powder No. 21 was decreased was that the Fe concentration was relatively decreased as the amount of Cr added was increased.
In addition, the addition amount of Cr is 1 to 4 atomic% No. In the soft magnetic alloy powders of 16, 18 to 20, ΔTx increases as the amount of Cr added increases, and it can be seen that the amorphous forming ability is improved.
[0131]
(Experimental example 4)
Fe, Fe-C alloy, Fe-P alloy, B, Si and Cr are weighed in predetermined amounts, respectively, and these raw materials are put in a molten crucible of the high-pressure water spray device shown in FIG. Then, the molten alloy is dropped from the molten metal nozzle of the molten crucible and high pressure water is sprayed from the water spray nozzle of the water sprayer shown in FIG. 1 to atomize the molten alloy, and the molten molten alloy is rapidly cooled in the chamber. When producing the soft magnetic alloy powder, the production conditions were changed to produce various soft magnetic alloy powders (No. 22 to 48 soft magnetic alloy powders).
[0132]
The composition of the obtained soft magnetic alloy powder is Fe_74.43Cr_1.96P_9.04, C_2.16B_7.54Si_4.87It was the composition which becomes.
In addition, the above Fe_74.43Cr_1.96P_9.04C_2.16B_7.54Si_4.87As a result of analysis of the structure of various soft magnetic alloy powders having the following composition by the X-ray diffraction method, the X-ray diffraction pattern of each alloy powder shows a broad pattern. It turns out that it is composed. Therefore, it can be seen that even an alloy composed of Fe, Cr, P, C, B, and Si can form an amorphous soft magnetic alloy powder composed of an amorphous phase. In FIG. The result of having analyzed the state of 23 soft-magnetic-alloy powder by a limited-field electron diffraction is shown.
Fe_74.43Cr_1.96P_9.04C_2.16B_7.54Si_4.87Various soft magnetic alloy powders having the composition described above were observed with a scanning electron microscope (SEM) to examine the shape. The results are shown in Tables 7 and 8. In FIG. The result of having observed 23 soft magnetic alloy powder by SEM is shown. In FIG. The result of having observed the structure | tissue state of 23 soft-magnetic alloy powder with the transmission electron microscope (TEM) is shown.
The average particle size of the obtained soft magnetic alloy powder (D₅₀Table 7 and Table 8 show the results of examining the minimum value, maximum value, and average value of the tap density, specific surface area, oxygen concentration, and aspect ratio.
[0133]
Furthermore, DSC measurement (Differential scanning caloriemetry) of various soft magnetic alloy powders obtained is performed to measure glass transition temperature Tg, crystallization start temperature Tx, Curie temperature Tc and melting point Tm. The temperature intervals ΔTx and Tg / Tm of the cooling liquid were determined. These results are shown in Tables 9 and 10. In addition, the temperature increase rate at the time of DSC measurement was 0.67 K / sec. In Tables 9 and 10, Tm * indicates the melting temperature of the alloy.
Further, the saturation magnetization σs of the various soft magnetic alloy powders obtained was measured in the same manner as in Experimental Example 1. These results are shown in Tables 9 and 10 together.
[0134]
Next, a granulated powder was prepared in the same manner as in Experimental Example 1 except that the soft magnetic alloy powder obtained in Experimental Example 4 was used. Further, in the same manner as in Experimental Example 1 using these granulated powders. Various powder cores were manufactured.
The core loss (W) of the various powder cores obtained was measured in the same manner as in Experimental Example 1. The results are shown in Tables 9 and 10. Further, the effective permeability (μ ′) and DC superposition characteristics (μ ′) of the various powder cores obtained._DC5500 ) Was measured in the same manner as in Experimental Example 1. The results are shown in Tables 9 and 10.
[0135]
[Table 7]

[0136]
[Table 8]

[0137]
[Table 9]

[0138]
[Table 10]

[0139]
From the results shown in Tables 7 to 10, No. 4 was obtained. It can be seen that the 22-48 soft magnetic alloy powders are substantially spherical.
However, no. 22 soft magnetic alloy powder has a specific surface area of 0.32m²It can be seen that the powder core produced using this soft magnetic alloy powder has a large core loss. No. 24 soft magnetic alloy powder has a tap density of 3.68 Mg / m³It can also be seen that the powder core produced using this soft magnetic alloy powder has a large core loss.
[0140]
On the other hand, D₅₀Is larger than 4 μm and not larger than 45 μm, and the tap density is 3.7 Mg / m.³The specific surface area is 0.3m²/ G or less and a powder core produced using a soft magnetic alloy powder (No. 25, 26, 27, 32, 35, 39, 40, 42, 44, 45, 46) with an oxygen concentration of 3000 ppm or less is a core loss. (W) 450 kW / m³In addition, the effective permeability μ ′ is 58 to 71, and the direct current bar direct current superimposition characteristic μ ′._DC5500Can be 31.5 to 34.5.
D₅₀Is larger than 4 μm and not larger than 16 μm, and the tap density is 4.0 Mg / m.³The specific surface area is 0.23m²/ G or less, and a dust core produced using soft magnetic alloy powder (No. 23, 28, 29, 30, 31, 33, 34, 36, 37, 38, 41) having an oxygen concentration of 2000 ppm or less is core loss. (W) is 250 kW / m³The effective permeability μ ′ is 61 to 70, and the DC superimposition characteristic μ ′_DC5500Can be 32 to 34.
Further, from the SEM photograph of FIG. It can be seen that the soft magnetic alloy powder No. 23 is substantially spherical. In addition, this No. As can be seen from the diffraction spot distribution form of FIG. 8, the soft magnetic alloy powder No. 23 has a halo pattern peculiar to the amorphous state, and is understood to be composed of an amorphous phase. Further, from the TEM photograph of FIG. It can be seen that the soft magnetic alloy powder No. 23 has a uniform structure and no mixed crystal phase.
[0141]
(Experimental example 5)
Fe, Fe-C alloy, Fe-P alloy, B, Si, Cr and Al, Mo, or V are respectively weighed in predetermined amounts, and these raw materials are melted in the high-pressure water spray apparatus shown in FIG. It melts in a crucible, and the molten alloy is dropped from the molten metal nozzle of the molten crucible, and high pressure water is sprayed from the water spray nozzle of the water sprayer shown in FIG. When a soft magnetic alloy powder was prepared by rapidly cooling the molten alloy, various soft magnetic alloy powders (No. 50 to 57 soft magnetic alloy powders) were prepared by changing the production conditions.
[0142]
The composition of the obtained soft magnetic alloy powder is Fe_100-t-yz-w-xP_ySi_tC_zB_wM_x(Wherein z is 2.16 to 2.18 atomic%, w is 7.54 to 7.62 atomic%, x is 1 atomic% to 1.96 atomic%, and y is 7 to 9.14 atomic%. , T was 3.87 to 10 atomic%). Note that M in the composition formula represents Cr, Mo, or V.
In addition, No. No. 56 soft magnetic alloy powder is No. The composition is the same as that of No. 23, but the average particle size (D₅₀), Average values of tap density, specific surface area, oxygen concentration, and aspect ratio are outside the scope of the present invention. No. 57 soft magnetic alloy powder is No. The composition is the same as that of No. 23, but the production conditions when producing by the water atomization method are different. More specifically, by reducing the water pressure during atomization, the cooling rate of the molten metal is also reduced, It becomes a powder in a mixed phase of amorphous and crystal.
In addition, the above Fe_100-t-yz-w-xP_ySi_tC_zB_wM_xAs a result of analyzing the structure of various soft magnetic alloy powders having the composition shown in FIG. 51, no. 53-No. The alloy powder No. 56 also shows a broad X-ray diffraction pattern and is composed of a structure composed of an amorphous phase. It was found that the X-ray diffraction pattern of 57 alloy powder showed a non-broad pattern. In FIG. The result of having analyzed the state of 57 soft-magnetic alloy powder by the limited-field electron diffraction is shown.
Therefore, in an alloy composed of Fe, Cr, P, C, B, Si, Mo or V, the average particle diameter (D₅₀), The average value of the tap density, specific surface area, oxygen concentration, and aspect ratio is within the range of the present invention, and the amorphous soft phase comprising the amorphous phase is controlled by controlling the production conditions when producing by the water atomization method. It can be seen that magnetic alloy powders (No. 51, No. 53 to No. 56) can be formed.
Fe_100-t-yz-w-xP_ySi_tC_zB_wM_xVarious soft magnetic alloy powders having the composition described above were observed with a scanning electron microscope (SEM) to examine the shape. The results are shown in Table 11. In FIG. The result of having observed 56 soft magnetic alloy powder by SEM is shown. In FIG. The result of having observed 57 soft magnetic alloy powder by TEM is shown. The average particle size of the obtained soft magnetic alloy powder (D₅₀Table 12 shows the results of examining the minimum value, maximum value, and average value of the tap density, specific surface area, oxygen concentration, and aspect ratio.
[0143]
Furthermore, DSC measurement (Differential scanning caloriemetry) of various soft magnetic alloy powders obtained is performed to measure glass transition temperature Tg, crystallization start temperature Tx, Curie temperature Tc and melting point Tm. The temperature intervals ΔTx and Tg / Tm of the cooling liquid were determined. These results are shown in Table 12. In addition, the temperature increase rate at the time of DSC measurement was 0.67 K / sec. In Table 12, Tm * indicates the melting temperature of the alloy.
Further, the saturation magnetization σs of the various soft magnetic alloy powders obtained was measured in the same manner as in Experimental Example 1. These results are shown in Table 12 together.
[0144]
Next, a granulated powder was prepared in the same manner as in Experimental Example 1 except that the soft magnetic alloy powder obtained in Experimental Example 5 was used. Further, in the same manner as in Experimental Example 1 using these granulated powders. Various powder cores were manufactured.
The core loss (W) of the various powder cores obtained was measured in the same manner as in Experimental Example 1. The results are also shown in Table 12.
Further, the effective permeability (μ ′) and DC superposition characteristics (μ ′) of the various powder cores obtained._DC5500 ) Was measured in the same manner as in Experimental Example 1. The results are also shown in Table 12.
[0145]
As a conventional alloy powder generally known for comparison, a composition of Fe—Cr—Si—B (Fe₇₃Cr₂B₁₅Si₁₀Structure, shape, average particle diameter (D₅₀), Tap density, specific surface area, oxygen concentration, aspect ratio, minimum value, maximum value, and average value were also measured in the same manner as in Experimental Example 1. These results are shown in Table 11 together. This No. The alloy powder of 52 is produced by a water atomization method. This No. The structure of the 52 alloy powder was found to have an amorphous phase and a crystalline phase.
No. The saturation magnetization σs of the alloy powder 52 was measured in the same manner as in Experimental Example 1. The results are also shown in Table 12. No. A granulated powder was produced in the same manner as in Experimental Example 1 except that the alloy powder of No. 52 was used. Further, a dust core was produced in the same manner as in Experimental Example 1 using these granulated powders. Core loss (W), effective permeability (μ ') and DC superposition characteristics (μ'_DC5500 ) Was measured in the same manner as in Experimental Example 1. The results are also shown in Table 12.
[0146]
[Table 11]

[0147]
[Table 12]

[0148]
From the results shown in Tables 11 and 12, No. The alloy powder No. 52 has a substantially spherical shape, but its structure is composed of an amorphous phase and an amorphous phase. The core loss of the powder core produced using the alloy powder of 52 is 1000 kW / cm.³It was more than that.
Further, from the SEM photograph of FIG. The soft magnetic alloy powder No. 56 has an indeterminate shape. It can be seen that the dust core using 56 soft magnetic alloy powder has large core loss and poor DC superposition characteristics.
In addition, this No. As is apparent from the diffraction spot distribution form of FIG. 9, the 57 soft magnetic alloy powder has a plurality of spots corresponding to the crystal structure, and is composed of an amorphous phase and a crystalline phase. I understand that. Further, from the TEM photograph of FIG. It can be seen that the soft magnetic alloy powder No. 57 has a non-uniform structure and a mixture of a crystalline phase and an amorphous phase. Further, from the results of Tables 11 to 12, this No. It can be seen that the core loss using the 57 soft magnetic alloy powder has a large core loss.
In contrast, no. It can be seen that the soft magnetic alloy powders 51, 53, 54, and 55 have a substantially spherical shape, and the structure is composed of an amorphous phase (amorphous phase).
[0149]
(Experimental example 6)
The particle size and fluidity of the granulated powder were examined.
Here, the flowability was measured by changing the particle size of the granulated powder when flowing 50 g of the granulated powder into a hole having a diameter of 2.5 mm and passing through the hole (seconds). The granulated powder used here was 1.4% by weight of silicone resin as an insulating material and 0.3% of zinc stearate as a lubricant with respect to 98.3% by weight of the amorphous soft magnetic alloy powder of the embodiment. It is a mixture and granulated with wt%. The granulated powder thus produced has a particle size of less than 45 μm, 45 μm to 150 μm, 150 μm to 300 μm, 300 μm to 500 μm, more than 500 μm, 45 μm to 300 μm, 45 μm or more It classify | categorized into the thing of -500 micrometers or less, and used for the fluidity | liquidity test (JIS 2502-1958).
[0150]
As a result, when the particle size of the granulated powder is less than 45 μm, it does not flow, when it is 45 μm or more and 150 μm or less, 44.5 seconds, when it is 150 μm or more and 300 μm or less, 50.4 seconds, when it is 300 μm or more and 500 μm or less Was 61.8 seconds, and when it exceeded 500 μm, it did not flow.
Therefore, it is understood that the particle size of the granulated powder is preferably 45 μm or more and 500 μm or less, more preferably 45 μm or more and 300 μm or less, and further preferably 45 μm or more and 150 μm or less.
[0151]
(Experimental example 7)
The mixing amount (% by weight) of the granulated powder having a particle size of less than 45 μm in the total granulated powder and the fluidity were examined. The results are shown in FIG. Here, the fluidity is the time when the granulated powder is poured into a hole having a diameter of 2.5 mm, the mixing amount of the granulated powder having a particle diameter of less than 45 μm in 50 g of the total granulated powder is changed, and the time for passing through the hole. (Seconds) was measured. The granulated powder used here was 1.4% by weight of silicone resin as an insulating material and 0.3% by weight of zinc stearate as a lubricant with respect to 98.3% by weight of the amorphous soft magnetic alloy powder of the embodiment. % And mixed and granulated. The granulated powders thus produced were classified into those having a particle size of less than 45 μm and those having a particle size of more than 45 μm and less than 500 μm, and used for the fluidity test (JIS 2502-1958).
From the results shown in FIG. 5, the fluidity is 60 seconds or less when the mixing amount of the granulated powder having a particle size of less than 45 μm is 17% by weight or less of the total granulated powder, and the fluidity is 15% by weight or less. It can be seen that the flowability is excellent in 50 seconds or less.
[0152]
(Experimental example 8)
No. 1 prepared in Experimental Example 4 above. 23 soft magnetic alloy powder (composition is Fe_74.43Cr_1.96P_9.04C_2.16B_7.54Si_4.87) Was used in the same manner as in Experimental Example 1 above, and granulated powders were produced in the same manner as in Experimental Example 1 using these granulated powders.
For comparison, a granulated powder was prepared in the same manner as in Experimental Example 1 except that Fe powder was used, and a powdered core (Comparative Example) was prepared in the same manner as in Experimental Example 1 using these granulated powders. 1) was produced.
Further, for comparison, a granulated powder was prepared in the same manner as in Experimental Example 1 except that Ni-Fe-Mo (Mo-based permalloy) powder conventionally used for a low-loss core was used. Further, using these granulated powders, a dust core (Comparative Example 2) was produced in the same manner as in Experimental Example 1. Further, a granulated powder was prepared in the same manner as in Experimental Example 1 except that Fe-Al-Si (Sendust) powder was used, and a powdered core was produced in the same manner as in Experimental Example 1 using these granulated powders. (Comparative Example 3) was produced.
[0153]
The core loss (W), relative effective magnetic permeability (μ ′), and direct current superposition characteristics (μ ′) of various powder cores obtained were measured.
The core loss here is measured when the frequency (f) is constant at 100 kHz and the saturation magnetic flux density (Bm) is 10 to 100 mT.
The relative effective magnetic permeability is a relative value of the measurement result of the effective magnetic permeability (μ ′) when the frequency (f) is changed in the range of 1 to 1000 kHz.
The DC superposition characteristics are constant at a current of 1 mA and a frequency (f) of 100 kHz, and a DC bias magnetic field (Hm) of 0 to 8000 Am.^-1The effective magnetic permeability (μ ′) when changed in the range is measured. The results are shown in FIGS.
Moreover, when the specific resistance ((rho)) of the obtained various powder cores was measured, the powder core of an Example is 307 kohm * cm, the powder core of the comparative example 2 is 0.5 ohm * cm, and the comparative example 3 The dust core was 1.7 kΩ · cm.
[0154]
From the result of FIG. The dust core of the example using 23 soft magnetic alloy powder used the powder core of the comparative example 1 using the powder of Fe, the powder of Ni-Fe-Mo, and the powder of Fe-Al-Si. It turns out that a core loss is low compared with Comparative Examples 2-3.
Moreover, although it is preferable that the core has a constant magnetic permeability in the range of the operating frequency, it is a comparative example using Fe powder or Ni—Fe—Mo powder in the range of 1 kHz to 1000 kHz (1 MHz) from the result of FIG. As the frequency of the powder cores 1 to 2 increases, the reduction rate of the effective permeability increases. In contrast, no. In the dust core of the example using the soft magnetic alloy powder of 23, the effective magnetic permeability is substantially constant at a frequency of 1 kHz to 1000 kHz, and the comparison using the Fe—Al—Si powder is performed in the above frequency range. The effective permeability is higher than that of the dust core of Example 3.
Further, when using the core, it is preferable that the magnetic permeability can be kept as constant as possible even when the DC bias magnetic field becomes large. From the result of FIG. 16, a comparison using Ni—Fe—Mo powder was made. It can be seen that the dust core of Example 2 is difficult to use because the effective permeability suddenly decreases as the magnetic field increases. On the other hand, the dust core of the example has an effective magnetic permeability even when the magnetic field is increased as in the dust cores of Comparative Example 1 and Comparative Example 3 using Fe powder or Fe—Al—Si powder. The rate of decline is small.
From these facts, the dust core of the example using the soft magnetic alloy powder of the present invention has a low core loss and can exhibit a certain permeability up to a high frequency, and the characteristics are stable when used as a core. And easy to use.
[0155]
(Experimental example 9)
No. produced in Experimental Example 4 above. A granulated powder was produced in the same manner as in Experimental Example 1 except that the substantially spherical soft magnetic alloy powder of No. 23 was used. Produced.
For comparison, No. 1 prepared in Experimental Example 5 was used. 56 amorphous soft magnetic alloy powder (composition is Fe_74.43Cr_1.96P_9.04C_2.16B_7.54Si_4.87) Was used in the same manner as in Experimental Example 1 above, and a powdered core (Comparative Example 4) was prepared in the same manner as in Experimental Example 1 using these granulated powders.
The core loss (W), the initial effective magnetic permeability (μ ′), and the DC superposition characteristics (μ ′) were measured for the produced dust cores of Example and Comparative Example 4.
The core loss here is constant when the saturation magnetic flux density (Bm) is 0.1 T and is changed in the frequency (f) range of 10 to 200 kHz.
The initial effective magnetic permeability is obtained by measuring the effective magnetic permeability (μ ′) when the frequency (f) is changed in the range of 1 to 1000 kHz.
The DC superposition characteristics are constant at a current of 1 mA and a frequency (f) of 100 kHz, and a DC bias magnetic field (Hm) of 0 to 8000 Am.^-1The effective magnetic permeability (μ ′) when changed in the range is measured. The results are shown in FIGS.
Moreover, the measurement result of the density (D) of the dust core of an Example and the comparative example 4 is shown in FIG.
[0156]
From the result of FIG. No. 23 using the soft magnetic alloy powder of the example No. 23 in the frequency range of 10 to 200 kHz. It can be seen that the core loss is low compared to the dust core of the example using 56 soft magnetic alloy powders.
Further, as described above, it is preferable that the core has a constant magnetic permeability in the range of the operating frequency, but from the result of FIG. 18, the powder core of Comparative Example 4 has a higher frequency in the range of 1 kHz to 1000 kHz. As the initial effective permeability decreases, the rate of decrease increases. On the other hand, the dust core of the example shows a substantially constant initial effective permeability in the above frequency range, and is easy to use when used as a core.
Further, from the results of FIG. 19, the effective permeability of Comparative Example 4 rapidly decreases as the applied magnetic field increases. On the other hand, the dust core of the example has a small decrease rate of the initial effective magnetic permeability even when the applied magnetic field is large, and 2500 Am^-1  From the above, it can be seen that the initial effective magnetic permeability is larger than that of Comparative Example 4.
Further, from the results of FIG. 20, the density of the dust core of Comparative Example 4 is about 5.5 g / cm.³However, the density of the dust core of the example is about 6 g / cm.³It can be seen that the density is larger than that of Comparative Example 4.
From these facts, the powder cores of the example and the comparative example 4 use soft magnetic alloy powders having the same composition, but due to the difference in the shape of the alloy powders, the above characteristics are different, Therefore, it can be seen that the use of the substantially spherical soft magnetic alloy powder has a lower core loss, can exhibit a constant magnetic permeability up to a frequency of 1000 kHz, has stable characteristics when used as a core, and is easy to use.
[0157]
(Experimental example 10)
No. produced in Experimental Example 4 above. The substantially spherical soft magnetic alloy powder of 23 was put into an attritor, and pulverized and mixed with an attritor dial 4 for 12 hours to produce the flat soft magnetic alloy powder of the example. The flat amorphous soft magnetic alloy powder of the example produced here had a thickness in the range of about 0.3 to 1 μm and a major axis in the range of about 10 to 76 μm. FIG. 21 shows the result of observation of the produced flat soft magnetic alloy powder of the example by SEM. As shown in FIG. It can be seen that the flattened soft magnetic alloy powder No. 23 has a shape close to a disk and is uniform in size.
Next, 55% by weight of a silicone elastomer is mixed as a material that serves as an insulating property and a binder with respect to 45% by weight of the flat soft magnetic alloy powder of the example. Was made.
[0158]
Further, for comparison, No. 1 prepared in Experimental Example 5 was used. 56 amorphous soft magnetic alloy powders were put in an attritor, and pulverized and mixed for 16 hours with an attritor dial 10 to produce a flat soft magnetic alloy powder of a comparative example. Among the produced flat soft magnetic alloy powders of Comparative Examples, those having a diameter of 63 to 106 μm were classified. In FIG. 22, the result of having observed the flat type soft magnetic alloy powder of the comparative example classified by SEM is shown. From FIG. It can be seen that the flattened one of 56 soft magnetic alloy powders is broken apart and the size is not uniform.
Next, 55% by weight of a silicone elastomer as a material for insulating and binder is mixed with 45% by weight of the classified flat soft magnetic alloy powder of the comparative example, and solidified and formed into a sheet shape to absorb the electromagnetic wave of the comparative example. The body was made.
[0159]
The effective permeability (μ ′) and imaginary permeability (μ ″) when the frequency was changed in the range of 1 MHz to 1000 MHz were measured for the fabricated wave absorbers of the example and the comparative example. The results are shown in FIG.
From the result of FIG. The wave absorber of the example using the flattened powder of the substantially spherical soft magnetic alloy powder of No. 23 is No. 2 in the range of 2 MHz to 1000 MHz. It can be seen that the effective magnetic permeability is higher than that of the radio wave absorber of the comparative example using the powder obtained by flattening the 56 amorphous soft magnetic alloy powder. In addition, it can be seen that the radio wave absorber of the example has a higher imaginary magnetic permeability than the radio wave absorber of the comparative example in the range of 7 MHz to 1000 MHz, and has an excellent electromagnetic wave suppression effect, particularly at 20 MHz or higher. It can be seen that a value of “15” or more (maximum 18) can be obtained.
[0160]
【The invention's effect】
  As described above in detail, the amorphous soft magnetic alloy powder of the present invention is a substantially spherical powder formed by a water atomization method,Average particle diameter of substantially spherical powder (D ₅₀ 44) . 32 μm or less, the tap density of the substantially spherical powder is 3 . 78Mg / m ³ As described above, the substantially spherical powder has an oxygen concentration of 2900 ppm or less, and the substantially spherical powder has a specific surface area of 0. . 28m ² / G or less,
  Fe_100-xyz-wtM_xP_yC_zB_wSi_tWhere M is one or more elements selected from Cr, Mo, W, V, Nb, Ta, Ti, Zr, Hf, Pt, Pd, and Au. X, y, z, w, and t indicating the ratio are 0.5 atomic% ≦ x ≦ 8 atomic%, 2 atomic% ≦ y ≦ 15 atomic%, 0 atomic% <z ≦ 8 atomic%, 1 atomic% ≦ Since w ≦ 12 atomic%, 4.37 atomic% ≦ t ≦ 8 atomic%, 70 atomic% ≦ (100−x−yz−w−t) ≦ 79 atomic%, high saturation magnetization and Combined with low core loss, the amorphous soft magnetic alloy powder of the present invention can be manufactured by the water atomization method, so the manufacturing equipment can be enlarged, and the molten alloy can be pulverized with high-pressure water for mass production. The manufacturing cost can be reduced because it is not necessary to use expensive inert gas.
  Since this amorphous soft magnetic alloy powder is formed in a shape close to a spherical shape by the water atomization method, there are advantages that the bulk density is high and the unevenness of the surface is small.
  In the present invention, the average particle diameter (D₅₀) Is 8.63 μm or more and 44.32 μm or moreUnderSome cases are preferred.
  According to the amorphous soft magnetic alloy powder having such a configuration, the core loss (W) when measured under the conditions of a frequency of 100 kHz and a magnetic flux density of 0.1 T is obtained.213kW / m³Can bePossibleAnd the real part μ ′ of the complex permeability up to a frequency of 1 MHz.60~70DC bias magnetic field 5500 Am^-1DC superposition characteristics (μ ′_DC5500) Can be made substantially constant at 30 to 34.5, so that it is possible to provide an amorphous soft magnetic alloy powder that is easy to use when used in a magnetic core.
  Further, in the present invention, if it is a dust core or a radio wave absorber using the above-mentioned amorphous soft magnetic alloy powder, a dust core or a radio wave absorber having the above-described excellent characteristics can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing an example of a high-pressure water spray apparatus used for producing an amorphous soft magnetic alloy powder of the present invention.
FIG. 2 is a perspective view showing a first embodiment of a dust core according to the present invention.
FIG. 3 is an exploded perspective view showing an example of a mold used for manufacturing the dust core of the present invention.
FIG. 4 is a schematic view of a main part of a discharge plasma sintering apparatus used when manufacturing the dust core of the present invention.
FIG. 5 is a graph showing the relationship between the mixing amount of granulated powder having a particle size of less than 45 μm and fluidity.
FIG. 6 is a perspective view showing another embodiment of the dust core of the present invention.
FIG. 7 is a perspective view showing another embodiment of the dust core of the present invention.
FIG. It is a figure which shows the result of the electron beam diffraction of 23 soft magnetic alloy powder.
FIG. It is a figure which shows the result of the electron beam diffraction of 57 soft magnetic alloy powder.
FIG. It is a SEM photograph of 23 soft magnetic alloy powder.
FIG. It is a SEM photograph of 56 soft magnetic alloy powders.
FIG. It is a TEM photograph of 23 soft magnetic alloy powder.
FIG. It is a TEM photograph of 57 soft magnetic alloy powder.
FIG. 14 is a diagram showing measurement results of core loss of the dust cores of Examples and Comparative Examples 1 to 3.
FIG. 15 is a diagram showing measurement results of relative effective magnetic permeability of the dust cores of Examples and Comparative Examples 1 to 3.
FIG. 16 is a diagram showing measurement results of direct current superposition characteristics of dust cores of Examples and Comparative Examples 1 to 3.
FIG. 17 is a diagram showing measurement results of core loss of the dust cores of Examples and Comparative Example 4;
FIG. 18 is a diagram showing the measurement results of the initial effective magnetic permeability of the dust cores of Examples and Comparative Example 4;
FIG. 19 is a diagram showing measurement results of direct current superposition characteristics of the dust cores of Examples and Comparative Example 4;
20 is a diagram showing the measurement results of the density of the dust cores of Examples and Comparative Example 4.
FIG. 21 is a SEM photograph of the flat soft magnetic alloy powder of the example.
FIG. 22 is an SEM photograph of a flat soft magnetic alloy powder of a comparative example.
FIG. 23 is a diagram showing the frequency dependence of the effective permeability and imaginary permeability of the radio wave absorbers of the example and the comparative example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... High pressure water spray apparatus, 2 ... Molten crucible, 3 ... Water sprayer, 4 ... Chamber, 5 ... Alloy molten metal, 6 ... Molten metal nozzle, 7 ... Introduction flow path, 8 ... Water injection nozzle, 10 ... High pressure water, 21 31, 41 ... compacted core, g ... high-pressure water flow, p ... spray point, [theta] ... water injection angle.

Claims (13)

It is a substantially spherical powder formed by a water atomization method, and the powder contains Fe as a main component and contains at least P, C, B, Si, Cr, Mo, W, V, Nb, Ta, Ti, Zr, One or more elements of Hf, Pt, Pd, and Au are included as M element and represented by the following composition formula: ΔTx = Tx−Tg (where Tx is the crystallization start temperature and Tg is the glass transition) The temperature interval ΔTx of the supercooled liquid represented by the equation of
Said substantially spherical average particle size of the powder _{(D 50)} is 44. 32 [mu] m or less, the generally tap density of the spherical powder is ^3. 78Mg / ^m 3 or more, the substantially spherical powder has an oxygen concentration of 2900ppm or less, the substantially spherical powder amorphous soft magnetic alloy powder, wherein the specific surface area of 0. 28 m 2 / ^g or less.
Fe _100-x-y-z-wt M _x P _y C _z B _{w S t}
However, x, y, z, w, and t indicating the composition ratio are 0.5 atomic% ≦ x ≦ 8 atomic%, 2 atomic% ≦ y ≦ 15 atomic%, 0 atomic% <z ≦ 8 atomic%, Atomic% ≦ w ≦ 12 atomic%, 4.37 atomic% ≦ t ≦ 8 atomic%, 70 atomic% ≦ (100−x−yz−w−t) ≦ 79 atomic%.   The amorphous soft magnetic alloy powder according to claim 1, wherein the average spherical powder has an average aspect ratio of 1 or more and 2.1 or less. Amorphous soft magnetic alloy powder according to claim 1 or 2 average particle diameter of the substantially spherical powder _{(D 50)} is equal to or more than 8.63Myuemu, and is under 44.32μm following. The core loss (W) under a condition of a frequency of 100 kHz and a magnetic flux density of 0.1 T is 213 kW / m ³ or less, a real part (μ ′) of complex permeability at a frequency of 1 MHz is 60 to 70 , and a DC bias magnetic field is 5500 A / m. amorphous soft magnetic alloy powder according to any one of claims 1 to 3 in which DC bias characteristics (μ _'DC5500) is characterized in that it is a 30 to 34.5 of. Wherein y indicating the composition ratio in the composition formula, z, w, t is 17 atomic% ≦ (y + z + w + t) any one of claims 1-4, characterized in that satisfy ≦ 29.5 atomic% the relationship Amorphous soft magnetic alloy powder described in 1. X, y, z, w, and t indicating the composition ratio in the composition formula are 1 atomic% ≦ x ≦ 4 atomic%, 4 atomic% ≦ y ≦ 14 atomic%, 0 atomic% <z ≦ 6 atomic%, 2 atom% ≦ w ≦ 10 atom%, 4.37 atom% ≦ t ≦ 8 atom%, 72 atom% ≦ (100−x−y−z−w−t) ≦ 79 atom% The amorphous soft magnetic alloy powder according to any one of claims 1 to 5 . X, y, z, w, and t indicating the composition ratio in the composition formula are 1 atomic% ≦ x ≦ 3 atomic%, 6 atomic% ≦ y ≦ 11 atomic%, 1 atomic% ≦ z ≦ 4 atomic%, 4 atom% ≦ w ≦ 9 atom%, 4.37 atom% ≦ t ≦ 7 atom%, 73 atom% ≦ (100−x−yz−w−t) ≦ 78 atom% are satisfied The amorphous soft magnetic alloy powder according to any one of claims 1 to 6 . The amorphous soft magnetic alloy according to any one of claims 1 to 7 , wherein t indicating a composition ratio in the composition formula is 4.37 atomic% ≤ t ≤ 4.87 atomic%. Powder. A flat amorphous soft magnetic alloy powder, wherein the amorphous soft magnetic alloy powder according to any one of claims 1 to 8 is flattened. A plurality or one of the amorphous soft magnetic alloy powders according to any one of claims 1 to 9, an insulating material and a lubricant are mixed and granulated powder, and the insulating material comprises A powder core characterized in that it is solidified as a binder. Dust core according to claim 1 0, wherein the content of the granulated powder having a particle size of 45μm or 500μm or less being greater than 83% by weight of the total granulated powder.   12. The dust core according to claim 11, wherein the content of the granulated powder having a particle size of less than 45 μm and a granulated powder having a particle size of greater than 500 μm is 17% by weight or less of the total granulated powder. A radio wave absorber formed by mixing the amorphous soft magnetic alloy powder according to any one of claims 1 to 8 or the flat amorphous soft magnetic alloy powder according to claim 9 and an insulating material.

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