JP3921348B2 - Multilayer ferrite parts - Google Patents

Description

【００２６】
【表２】

【００２７】
表２および図７曲線ａにおいて、焼結体中に占めるＣｏ換算でのＣｏの量（以下、Ｃｏ量）が０.００６ｗｔ％の場合（Ｎｏ.１）の破壊電圧（ＶＢ）は１.８１ｋＶであり良好な値を示している。Ｃｏ量が０.１０３ｗｔ％（Ｎｏ.２）になると破壊電圧（ＶＢ）は２.９６ｋＶまで向上し、Ｃｏ量が０.２００ｗｔ％の場合（Ｎｏ.３）には破壊電圧（ＶＢ）は更に向上して３.０１ｋＶとなる。この値をピークとして次第に破壊電圧（ＶＢ）は低下するものの、Ｃｏ量が０.４８８ｗｔ％の場合（Ｎｏ.４）の破壊電圧（ＶＢ）は２.８３ｋＶ、Ｃｏ量が０.７００ｗｔ％の場合（Ｎｏ.５）においても破壊電圧（ＶＢ）は２.６６ｋＶと良好な値を示している。ところが、Ｃｏ量が０.７００ｗｔ％（Ｎｏ.５）を超えると破壊電圧（ＶＢ）は大幅に低下し、Ｃｏ量が１.０２０ｗｔ％の場合（Ｎｏ.６）には、破壊電圧（ＶＢ）は１.７５ｋＶまで低下した。
【００２８】
さらに表２には、破壊電圧（ＶＢ）を磁性フェライト層４２の厚さｄ（６０μｍ）で割った値も示している。ここで、積層型チップコンデンサ４１の場合、積層方向に隣接する内部電極４３同士に電位差が生じる。したがって、この値は電位差の生じている導体間に存在する磁性フェライト層４２の１μｍあたりの破壊電圧（Ｖｂ＝ＶＢ／ｄ）であり、Ｎｏ.１〜５では３０Ｖ以上の優れた破壊電圧（Ｖｂ）を得ている。このなかで、Ｎｏ.２〜５では４０Ｖ以上、Ｎｏ.２〜４では４５Ｖ以上の特に優れた破壊電圧（Ｖｂ）を得ていることが注目される。
【００２９】
また表２および図８曲線ａにおいて、絶縁抵抗（ＩＲ）もＣｏ量と関連性を有している。Ｃｏ量が０.００６ｗｔ％の場合（Ｎｏ.１）の絶縁抵抗（ＩＲ）は７００ＭΩである。Ｃｏ量が０.１０３ｗｔ％（Ｎｏ.２）およびＣｏ量が０.２００ｗｔ％の場合（Ｎｏ.３）には、絶縁抵抗（ＩＲ）は１００００ＭΩ以上の優れた値を示す。Ｃｏ量が０.４８８ｗｔ％の場合（Ｎｏ.４）の絶縁抵抗（ＩＲ）は９２５０ＭΩ、Ｃｏ量が０.７００ｗｔ％の場合（Ｎｏ.５）の絶縁抵抗（ＩＲ）は６３００ＭΩと、ともに良好な値を示しているものの、Ｃｏ量が１.０２０ｗｔ％（Ｎｏ.６）になると絶縁抵抗（ＩＲ）は１５１０ＭΩまで低下してしまう。
【００３０】
次に、表２，図９曲線ａ，図１０曲線ａを用いて、実施例ａによるフェライト焼結部材のＣｏ量と透磁率（μ）、およびＣｏ量と品質係数（Ｑ）の相関関係について説明する。
表２および図９曲線ａにおいて、Ｃｏ量が０.００６ｗｔ％の場合（Ｎｏ.１）に最良の透磁率（μ）を示しており、Ｃｏ量が０.１０３ｗｔ％（Ｎｏ.２）、０.２００ｗｔ％（Ｎｏ.３）と増加するにつれて透磁率（μ）は次第に低下する。一方、表２および図１０曲線ａを見ると、品質係数（Ｑ）もＣｏ量と関連性を有していることがわかる。Ｃｏ量が０.００６ｗｔ％の場合（Ｎｏ.１）の品質係数（Ｑ）は４０である。Ｃｏ量が０.１０３ｗｔ％の場合（Ｎｏ.２）およびＣｏ量が０.２００ｗｔ％の場合（Ｎｏ.３）には品質係数（Ｑ）は１００以上の優れた値を示す。この値をピークとして品質係数（Ｑ）は次第に低下し、Ｃｏ量が０.４８８ｗｔ％の場合（Ｎｏ.４）には９４、Ｃｏ量が０.７００ｗｔ％の場合（Ｎｏ.５）は７５となるが、依然として良好な値を示している。さらにＣｏ量が増加して１.０２０ｗｔ％（Ｎｏ.６）になると、品質係数（Ｑ）は５０まで低下した。
【００３１】
＜実施例ｂ＞
実施例ｂは、表３に示す配合組成で、実施例ａと同様の製造条件で積層型コンデンサを作製し、破壊電圧（ＶＢ）および絶縁抵抗（ＩＲ）の測定を行なった。また、測定用コアを作製して透磁率（μ）および品質係数（Ｑ）を測定した。
測定された結果を表４に示す。また、Ｃｏ量による破壊電圧（ＶＢ）の変動を示すグラフを図７（曲線ｂ）に、Ｃｏ量による絶縁抵抗（ＩＲ）の変動を示すグラフを図８（曲線ｂ）に、Ｃｏ量による透磁率（μ）の変動を示すグラフを図９（曲線ｂ）に、またＣｏ量による品質係数（Ｑ）の変動を示すグラフを図１０（曲線ｂ）にそれぞれ示す。
【００３２】
【表３】

【００３３】
【表４】

【００３４】
表４および図７曲線ｂにおいて、焼結体中に占めるＣｏ量が０.００６ｗｔ％の場合（Ｎｏ.７）の破壊電圧（ＶＢ）は１.９９ｋＶである。Ｃｏ量が０.１０３ｗｔ％（Ｎｏ.８）になると破壊電圧（ＶＢ）は２.９１ｋＶまで向上し、Ｃｏ量が０.２００ｗｔ％の場合（Ｎｏ.９）には破壊電圧（ＶＢ）は更に向上して２.９６ｋＶとなる。また、Ｃｏ量が０.４８８ｗｔ％の場合（Ｎｏ.１０）およびＣｏ量が０.７００ｗｔ％の場合（Ｎｏ.１１）においても２.０ｋＶ以上の良好な破壊電圧（ＶＢ）を得ている。ところが、Ｃｏ量が１.０２０ｗｔ％の場合（Ｎｏ.１２）には、破壊電圧（ＶＢ）は１.７９ｋＶまで低下した。
【００３５】
さらに表４には、破壊電圧（ＶＢ）を磁性フェライト層４２の厚さｄ（６０μｍ）で割った値、つまり磁性フェライト層４２の１μｍあたりの破壊電圧（Ｖｂ＝ＶＢ／ｄ）も示している。Ｎｏ.７〜１１はいずれも３０Ｖ以上という優れた破壊電圧（Ｖｂ）を得ている。このなかで、Ｎｏ.８〜１１は４０Ｖ以上、Ｎｏ.８〜１０では４５Ｖ以上という特に優れた破壊電圧（Ｖｂ）を得ていることが注目される。
【００３６】
また表４および図８曲線ｂにおいて、絶縁抵抗（ＩＲ）もＣｏ量と関連性を有している。Ｃｏ量が０.００６ｗｔ％の場合（Ｎｏ.７）の絶縁抵抗（ＩＲ）は１５２０ＭΩである。Ｃｏ量が０.１０３ｗｔ％（Ｎｏ.８）になると絶縁抵抗（ＩＲ）が９５００ＭΩまで急激に向上し、Ｃｏ量が０.２００ｗｔ％の場合（Ｎｏ.９）に絶縁抵抗（ＩＲ）はピーク値９７００ＭΩを示す。Ｃｏ量が０.４８８ｗｔ％の場合（Ｎｏ.１０）およびＣｏ量が０.７００ｗｔ％（Ｎｏ.１１）の場合においても絶縁抵抗（ＩＲ）は５０００ＭΩ以上の良好な値を示している。ところが、Ｃｏ量が０.７００ｗｔ％（Ｎｏ.１１）を超えると絶縁抵抗（ＩＲ）は急激に低下し、Ｃｏ量が１.０２０ｗｔ％の場合（Ｎｏ.１２）には１４３０ＭΩまで低下した。
【００３７】
次に、表４，図９曲線ｂ，図１０曲線ｂを用いて、実施例ｂによるフェライト焼結部材のＣｏ量と透磁率（μ）、およびＣｏ量と品質係数（Ｑ）の相関関係について説明する。
図９曲線ｂはＣｏ量の増加に伴い透磁率（μ）が次第に低下することを示している。一方、図１０曲線ｂはＣｏ量を所定量の範囲にすることによって、きわめて良好な品質係数（Ｑ）を得ることができることを示している。
表４において、Ｃｏ量が０.００６ｗｔ％の場合（Ｎｏ.７）には、透磁率（μ）が４５７、品質係数（Ｑ）が５０と、ともに良好な値を示している。Ｃｏ量が０.１０３ｗｔ％（Ｎｏ.８）になると、透磁率（μ）は３００に低下するものの、品質係数（Ｑ）が１００まで向上することが注目される。Ｃｏ量が０.２００ｗｔ％の場合（Ｎｏ.９）、Ｃｏ量が０.４８８ｗｔ％の場合（Ｎｏ.１０）およびＣｏ量が０.７００ｗｔ％の場合（Ｎｏ.１１）においても品質係数（Ｑ）は６０以上という優れた結果を示している。ところが、Ｃｏ量が１.０２０ｗｔ％の場合（Ｎｏ.１２）には、Ｃｏ量が０.００６ｗｔ％の場合（Ｎｏ.７）以下の品質係数（Ｑ）まで低下してしまう。
【００３８】
＜実施例ｃ＞
実施例ｃは、表５に示す配合組成で、実施例ａと同様の製造条件で積層型コンデンサを作製し、破壊電圧（ＶＢ）および絶縁抵抗（ＩＲ）の測定を行なった。また、測定用コアを作製して透磁率（μ）および品質係数（Ｑ）を測定した。
測定された結果を表６に示す。また、Ｃｏ量による破壊電圧（ＶＢ）の変動を示すグラフを図７（曲線ｃ）に、Ｃｏ量による絶縁抵抗（ＩＲ）の変動を示すグラフを図８（曲線ｃ）に、Ｃｏ量による透磁率（μ）の変動を示すグラフを図９（曲線ｃ）に、またＣｏ量による品質係数（Ｑ）の変動を示すグラフを図１０（曲線ｃ）にそれぞれ示す。
【００３９】
【表５】

【００４０】
【表６】

【００４１】
表６および図７曲線ｃにおいて、焼結体中に占めるＣｏ量が０.００６ｗｔ％の場合（Ｎｏ.１３）の破壊電圧（ＶＢ）は２.２７ｋＶであり、良好な値を示している。Ｃｏ量が０.１０３ｗｔ％（Ｎｏ.１４）になると破壊電圧（ＶＢ）は２.７１ｋＶまで向上し、Ｃｏ量が０.２００ｗｔ％（Ｎｏ.１５）になると破壊電圧（ＶＢ）は更に向上して３.０１ｋＶとなる。この値をピークに破壊電圧（ＶＢ）は次第に低下し、Ｃｏ量が０.７００ｗｔ％（Ｎｏ.１７）の場合には２.３５ｋＶと、Ｃｏ量が０.００６ｗｔ％の場合（Ｎｏ.１３）と同じレベルの破壊電圧（ＶＢ）まで低下した。さらに、Ｃｏ量が１.０２０ｗｔ％の場合（Ｎｏ.１８）には、破壊電圧（ＶＢ）は１.５２ｋＶまで低下した。
【００４２】
さらに表６には、破壊電圧（ＶＢ）を磁性フェライト層４２の厚さｄ（６０μｍ）で割った値、つまり磁性フェライト層４２の１μｍあたりの破壊電圧（Ｖｂ＝ＶＢ／ｄ）も示している。Ｎｏ.１３〜１７はいずれも３０Ｖ以上という優れた破壊電圧（Ｖｂ）を得ている。このなかで、Ｃｏ量が０.１０３ｗｔ％の場合（Ｎｏ.１４）、Ｃｏ量が０.２００ｗｔ％の場合（Ｎｏ.１５）およびＣｏ量が０.４８８ｗｔ％の場合（Ｎｏ.１６）には、いずれも４０Ｖ以上という非常に優れた破壊電圧（Ｖｂ）を得ていることが注目される。
【００４３】
また表６および図８曲線ｃにおいて、絶縁抵抗（ＩＲ）もＣｏ量と関連性を有している。Ｃｏ量が０.００６ｗｔ％の場合（Ｎｏ.１３）の絶縁抵抗（ＩＲ）は３２００ＭΩである。Ｃｏ量が０.１０３ｗｔ％（Ｎｏ.１４）になると絶縁抵抗（ＩＲ）が８３００ＭΩまで向上し、Ｃｏ量が０.２００ｗｔ％の場合（Ｎｏ.１５）には絶縁抵抗（ＩＲ）は更に向上して９０００ＭΩとなる。ところが、Ｃｏ量が０.７００ｗｔ％（Ｎｏ.１７）を超えると絶縁抵抗（ＩＲ）は急激に低下し、Ｃｏ量が１.０２０ｗｔ％の場合（Ｎｏ.１８）には８５１ＭΩまで低下してしまう。
【００４４】
次に、表６，図９曲線ｃ，図１０曲線ｃを用いて、実施例ｃによるフェライト焼結部材のＣｏ量と透磁率（μ）、およびＣｏ量と品質係数（Ｑ）の相関関係について説明する。表６および図９曲線ｃに示すように、Ｃｏを添加することにより透磁率（μ）は若干減少するものの、Ｎｏ.１３〜１７においては品質係数（Ｑ）はいずれも６０以上と良好な値を示している（表６および図１０曲線ｃ参照）。このなかで、Ｃｏ量が０.１０３ｗｔ％の場合（Ｎｏ.１４）、Ｃｏ量が０.２００ｗｔ％の場合（Ｎｏ.１５）およびＣｏ量が０.４８８ｗｔ％の場合（Ｎｏ.１６）には、品質係数（Ｑ）はいずれも７０以上と特に良好な値を示している。ところが、Ｃｏ量が０.７００ｗｔ％（Ｎｏ.１７）を超えると、品質係数（Ｑ）は大幅に低下し、Ｃｏ量が１.０２０ｗｔ％（Ｎｏ.１８）の場合には、品質係数（Ｑ）は３４まで低下してしまう。
【００４５】
＜実施例ｄ＞
実施例ｄは、表７に示す配合組成で、実施例ａと同様の製造条件で積層型コンデンサを作製し、破壊電圧（ＶＢ）および絶縁抵抗（ＩＲ）の測定を行なった。また、測定用コアを作製して透磁率（μ）および品質係数（Ｑ）を測定した。
測定された結果を表８に示す。また、Ｃｏ量による破壊電圧（ＶＢ）の変動を示すグラフを図７（曲線ｄ）に、Ｃｏ量による絶縁抵抗（ＩＲ）の変動を示すグラフを図８（曲線ｄ）に、Ｃｏ量による透磁率（μ）の変動を示すグラフを図９（曲線ｄ）に、またＣｏ量による品質係数（Ｑ）の変動を示すグラフを図１０（曲線ｄ）にそれぞれ示す。
【００４６】
【表７】

【００４７】
【表８】

【００４８】
表８および図７曲線ｄにおいて、焼結体中に占めるＣｏ量が１.０２０ｗｔ％の場合（Ｎｏ.２４）を除いたＮｏ.１９〜２３では２.０ｋＶ以上の破壊電圧（ＶＢ）を示している。破壊電圧（ＶＢ）がピークとなるのはＣｏ量が０.２００ｗｔ％の場合（Ｎｏ.２１）であり、Ｎｏ.２０〜２２は２.５ｋＶ以上の優れた破壊電圧（ＶＢ）を得ている。
さらに表８には、破壊電圧（ＶＢ）を磁性フェライト層４２の厚さｄ（６０μｍ）で割った値、つまり磁性フェライト層４２の１μｍあたりの破壊電圧（Ｖｂ＝ＶＢ／ｄ）も示している。Ｎｏ.１９〜２３はいずれも３０Ｖ以上という優れた破壊電圧（Ｖｂ）を得ている。このなかで、Ｎｏ.２０〜２３はいずれも４０Ｖ以上の特に優れた破壊電圧（Ｖｂ）を得ていることが注目される。
【００４９】
また表８および図８曲線ｄにおいて、絶縁抵抗（ＩＲ）もＣｏ量と関連性を有している。Ｃｏ量が０.００６ｗｔ％の場合（Ｎｏ.１９）の絶縁抵抗（ＩＲ）は２６３０ＭΩである。Ｃｏ量が０.１０３ｗｔ％（Ｎｏ.２０）になると絶縁抵抗（ＩＲ）が７３００ＭΩまで急激に向上し、Ｃｏ量が０.２００ｗｔ％の場合（Ｎｏ.２１）には絶縁抵抗（ＩＲ）は更に向上して８２００ＭΩとなる。この値をピークとして絶縁抵抗（ＩＲ）は次第に低下し、Ｃｏ量が１.０２０ｗｔ％の場合（Ｎｏ.２４）には絶縁抵抗（ＩＲ）は７０８ＭΩまで低下した。
【００５０】
次に、表８，図９曲線ｄ，図１０曲線ｄを用いて、実施例ｄによるフェライト焼結部材のＣｏ量と透磁率（μ）、およびＣｏ量と品質係数（Ｑ）の相関関係について説明する。表８および図９曲線ｄに示すように、Ｃｏを添加することにより透磁率（μ）は若干低下する。一方、表８および図１０曲線ｄに示すように、Ｎｏ.１９〜２３では品質係数（Ｑ）はいずれも５０以上と良好な値を得ている。このなかで、Ｎｏ.２０〜２２の品質係数（Ｑ）はいずれも７０以上と、特に優れた値を示している。ところが、Ｃｏ量が１.０２０ｗｔ％（Ｎｏ.２４）の場合には品質係数（Ｑ）は３８まで低下してしまう。
【００５１】
＜実施例ｅ＞
実施例ｅは、表９に示す配合組成で、実施例ａと同様の製造条件で積層型コンデンサを作製し、破壊電圧（ＶＢ）および絶縁抵抗（ＩＲ）の測定を行なった。また、測定用コアを作製して透磁率（μ）および品質係数（Ｑ）を測定した。
測定された結果を表１０に示す。また、Ｃｏ量による破壊電圧（ＶＢ）の変動を示すグラフを図７（曲線ｅ）に、Ｃｏ量による絶縁抵抗（ＩＲ）の変動を示すグラフを図８（曲線ｅ）に、Ｃｏ量による透磁率（μ）の変動を示すグラフを図９（曲線ｅ）に、またＣｏ量による品質係数（Ｑ）の変動を示すグラフを図１０（曲線ｅ）にそれぞれ示す。
【００５２】
【表９】

【００５３】
【表１０】

【００５４】
表１０および図７曲線ｅにおいて、焼結体中に占めるＣｏ量が０.００６ｗｔ％の場合（Ｎｏ.２５）の破壊電圧（ＶＢ）は１.８２ｋＶである。Ｃｏ量が０.１０３ｗｔ％（Ｎｏ.２６）になると破壊電圧（ＶＢ）は２.３２ｋＶまで向上し、Ｃｏ量が０.２００ｗｔ％の場合（Ｎｏ.２７）およびＣｏ量が０.４８８ｗｔ％の場合（Ｎｏ.２８）にも２.０ｋＶ以上の良好な破壊電圧（ＶＢ）を示している。ところが、Ｃｏ量が１.０２０ｗｔ％（Ｎｏ.３０）になると、破壊電圧（ＶＢ）は１.４５ｋＶまで低下した。
【００５５】
さらに表１０には、破壊電圧（ＶＢ）を磁性フェライト層４２の厚さｄ（６０μｍ）で割った値、つまり磁性フェライト層４２の１μｍあたりの破壊電圧（Ｖｂ＝ＶＢ／ｄ）も示している。Ｎｏ.２５〜２９はいずれも３０Ｖ以上という優れた破壊電圧（Ｖｂ）を得ているのに対し、Ｃｏ量が１.０２０ｗｔ％の場合（Ｎｏ.３０）には、破壊電圧（Ｖｂ）は２４.２Ｖまで低下した。
【００５６】
また表１０および図８曲線ｅにおいて、絶縁抵抗（ＩＲ）もＣｏ量と関連性を有している。Ｃｏ量が０.００６ｗｔ％の場合（Ｎｏ.２５）の絶縁抵抗（ＩＲ）は７２８ＭΩである。Ｃｏ量が０.１０３ｗｔ％（Ｎｏ.２６）になると絶縁抵抗（ＩＲ）が３９８０ＭΩまで向上し、Ｃｏ量が０.２００ｗｔ％の場合（Ｎｏ.２７）には絶縁抵抗（ＩＲ）は更に向上して４３１０ＭΩとなる。Ｃｏ量が０.７００ｗｔ％（Ｎｏ.２９）を超えると絶縁抵抗（ＩＲ）は急激に低下し、Ｃｏ量が１.０２０ｗｔ％の場合（Ｎｏ.３０）には４１７ＭΩまで低下してしまう。
【００５７】
次に、表１０，図９曲線ｅ，図１０曲線ｅを用いて、実施例ｅによるフェライト焼結部材のＣｏ量と透磁率（μ）、およびＣｏ量と品質係数（Ｑ）の相関関係について説明する。表１０および図９曲線ｅに示すように、Ｃｏを添加することにより透磁率（μ）は若干低下するものの、Ｎｏ.２５〜２９においては品質係数（Ｑ）はいずれも４０以上と良好な値を示している。ところが、Ｃｏ量が１.０２０ｗｔ％（Ｎｏ.３０）の場合には品質係数（Ｑ）は３２まで低下した。
【００５８】
＜比較例１＞
比較例１は、表１１に示す配合組成で、実施例ａと同様の製造条件で積層型コンデンサを作製し、破壊電圧（ＶＢ）および絶縁抵抗（ＩＲ）の測定を行なった。また、測定用コアを作製して透磁率（μ）および品質係数（Ｑ）を測定した。
測定された結果を表１２に示す。また、Ｃｏ量による破壊電圧（ＶＢ）の変動を示すグラフを図７（曲線ｆ）に、Ｃｏ量による絶縁抵抗（ＩＲ）の変動を示すグラフを図８（曲線ｆ）に、Ｃｏ量による透磁率（μ）の変動を示すグラフを図９（曲線ｆ）に、またＣｏ量による品質係数（Ｑ）の変動を示すグラフを図１０（曲線ｆ）にそれぞれ示す。
【００５９】
【表１１】

【００６０】
【表１２】

【００６１】
図７において、実施例ａ〜ｅにかかる曲線ａ〜ｅと比較例１にかかる曲線ｆを対比すると、曲線ｆではＣｏ添加による破壊電圧（ＶＢ）の上昇率がほとんどみられないことがわかる。
また図８〜１０を見ると、比較例１にかかる曲線ｆは、絶縁抵抗（ＩＲ），透磁率（μ）および品質係数（Ｑ）においても、曲線ａ〜ｅと比較して低いレベルにあることが明らかである。
【００６２】
＜実施例の評価＞
以上、実施例ａ〜ｅ，比較例１の破壊電圧（ＶＢ），絶縁抵抗（ＩＲ），透磁率（μ）および品質係数（Ｑ）の測定結果を示した。以下、これらの結果に基づき、実施例の評価を行なう。
▲１▼破壊電圧（ＶＢ）についての評価
最初に図７を用いて、破壊電圧（ＶＢ）についての評価を行なう。
図７に示すように、破壊電圧（ＶＢ）は曲線ａ〜ｆの順位になっている。そして、曲線ａ〜ｅと比べて、曲線ｆが低いレベルにあることは一目瞭然である。ここで曲線ａのＭｎ量は０.０７０ｗｔ％、曲線ｂのＭｎ量は０.１６８ｗｔ％、曲線ｃのＭｎ量は０.３５７ｗｔ％、曲線ｄのＭｎ量は０.５４４ｗｔ％、曲線ｅのＭｎ量は０.７３２ｗｔ％、曲線ｆのＭｎ量は１.０２８ｗｔ％である。よって、良好な破壊電圧（ＶＢ）を得るためには、焼結体中に占めるＭｎ量を０.７５ｗｔ％以下（０を含まず）とする必要があることがわかった。
また、Ｍｎ量が本発明で推奨する範囲にある曲線ａ〜ｅにおいて、焼結体中に占めるＣｏ量が０.７００ｗｔ％を超えて１.０２０ｗｔ％になると、破壊電圧（ＶＢ）は１.８ｋＶ以下にまで低下する。この傾向から、優れた破壊電圧（ＶＢ）を得るためには、焼結体中に占めるＭｎ量を０.７５ｗｔ％以下（０を含まず）とするとともに、焼結体中に占めるＣｏ量を本発明で推奨する所定の範囲、すなわち０.７５ｗｔ％以下（０を含まず）とする必要があることが明らかとなった。
【００６３】
次に、焼結体中に占めるＭｎ量およびＣｏ量がともに本発明で推奨する範囲において、特に優れた破壊電圧（ＶＢ）を得ることができる範囲を検討する。
焼結体中に占めるＣｏ量が０.７５ｗｔ％以下の範囲において、特に良好な破壊電圧（ＶＢ）を得ているのは曲線ａ〜ｄである。曲線ａは２.５ｋＶ以上の優れた破壊電圧（ＶＢ）を呈しており、また曲線ｂ〜ｄも、曲線ａほどではないにしても、広範囲にわたって２.０ｋＶ以上の破壊電圧（ＶＢ）を得ていることが注目される。したがって、特に優れた破壊電圧（ＶＢ）を得るためには、焼結体中に占めるＭｎ量を０.６ｗｔ％以下とし、かつＣｏ量を０.７５ｗｔ％以下の範囲とすることが望ましい。さらに望ましいＭｎ量は０.２ｗｔ％以下である。また、Ｍｎ量が０.０７０ｗｔ％である曲線ａにおいて良好な破壊電圧（ＶＢ）を得ていることから、Ｍｎ量が０.０１ｗｔ％程度含有されれば良好な破壊電圧（ＶＢ）が得られると推測される。Ｃｏ量については、Ｃｏ量が０.２ｗｔ％のときに曲線ａ〜ｄがピーク値を得ていることから、Ｃｏ量は０.０５〜０.６ｗｔ％、さらには０.１〜０.４ｗｔ％とすることが望ましい。
【００６４】
曲線ｅも、曲線ａ〜ｄと同様に、Ｃｏ量が０.２ｗｔ％のときに破壊電圧（ＶＢ）がピークとなり、約２.５ｋＶの優れた値を示す。一方、曲線ａ〜ｄはＣｏ量が０.７５ｗｔ％前後のときにおいても２.５ｋＶ近辺の破壊電圧（ＶＢ）を示しているのに対し、曲線ｅはＣｏ量が０.７００ｗｔ％になると破壊電圧（ＶＢ）が２.０ｋＶより低い値となってしまう。この傾向から、焼結体中に占めるＭｎ量が０.６ｗｔ％以上であるときには、Ｃｏ量を０.０５〜０.６ｗｔ％、さらには０.１〜０.４ｗｔ％とすることが望ましい。焼結体中に占めるＭｎ量が０.６ｗｔ％以上であるときには、Ｃｏ量を０.０５〜０.６ｗｔ％とすることにより、２.０ｋＶ以上の優れた破壊電圧（ＶＢ）を得ることができる。
【００６５】
▲２▼絶縁抵抗（ＩＲ）についての評価
次に、図８を用いて、絶縁抵抗（ＩＲ）についての評価を行なう。
図８に示されるように、絶縁抵抗（ＩＲ）は曲線ａ〜ｆの順位となっている。そして、破壊電圧（ＶＢ）の場合と同様に、曲線ａ〜ｆのなかで曲線ｆの絶縁抵抗（ＩＲ）のレベルは低いものとなっている。したがって、良好な絶縁抵抗（ＩＲ）を得るためにも、焼結体中に占めるＭｎ量を０.７５ｗｔ％以下（０を含まず）とすることが必要であるといえる。
また、Ｍｎ量，Ｃｏ量がともに本発明で推奨する範囲、すなわち０.７５ｗｔ％以下にある曲線ａ〜ｅにおいて、良好な絶縁抵抗（ＩＲ）を得ているのは曲線ａ〜ｄである。このなかで特に良好な絶縁抵抗（ＩＲ）を得ているのは曲線ａおよびｂである。よって、焼結体中に占めるＭｎ量を０.６ｗｔ％以下、さらに望ましくは０.２ｗｔ％以下とすることにより、非常に優れた絶縁抵抗（ＩＲ）を得ることが可能となる。もっとも、Ｍｎ量があまり低くなるとその効果を享受することができなくなるので、０.０１ｗｔ％以上、さらに０.０３ｗｔ％以上の範囲で含有せしめるのが望ましい。さらに、絶縁抵抗（ＩＲ）についても焼結体中に占めるＣｏ量が０.２ｗｔ％のときにピーク値を得ていることから、Ｃｏ量の最適範囲は０.０５〜０.６ｗｔ％、さらには０.０１〜０.４ｗｔ％であるといえる。
【００６６】
▲３▼透磁率（μ）についての評価
次に、図９を用いて、透磁率（μ）についての評価を行なう。
図９では、曲線ａ〜ｅがほぼ同等レベルにあり、曲線ｆのみが低いレベルにあることが示されている。したがって、良好な透磁率（μ）を得るためにも、焼結体中に占めるＭｎ量を０.７５ｗｔ％以下（０を含まず）とすればよい。
また、曲線ａ〜ｅのなかでは、曲線ｃ〜ｅが特に良好な透磁率（μ）を示しており、次いで曲線ｂ、曲線ａとなっている。つまり、上述の破壊電圧（ＶＢ）および絶縁抵抗（ＩＲ）とは異なる傾向を示している。この傾向から、透磁率（μ）についてのＭｎ量の望ましい範囲は０.１〜０.７５ｗｔ％、さらには０.３〜０.７５ｗｔ％であるといえる。
さらに、曲線ａ〜ｅにおいても、１５０以上の良好な透磁率（μ）を確保するためには、焼結体中に占めるＣｏ量を本発明で推奨する範囲、すなわち０.７５ｗｔ％以下とすることが望ましい。
【００６７】
▲４▼品質係数（Ｑ）についての評価
次に、図１０を用いて、品質係数（Ｑ）についての評価を行なう。
図１０を見ると、品質係数（Ｑ）も曲線ａ〜ｆの順位となっており、曲線ｆの品質係数（Ｑ）はそのピーク値においても４０以下となっている。したがって、４０以上の良好な品質係数（Ｑ）を得るためには、焼結体中に占めるＭｎ量を０.７５ｗｔ％以下（０を含まず）とする必要があることがわかった。
曲線ａ〜ｅのなかで特に良好な品質係数（Ｑ）を得ているのは曲線ａおよびｂであり、曲線ｅは曲線ａ〜ｄと比較すると低いレベルとなっている。したがって、良好な品質係数（Ｑ）を得るためには、焼結体中に占めるＭｎ量が０.７５ｗｔ％を超えないようにＭｎを含めばよい。より望ましいＭｎ量は０.１〜０.６ｗｔ％、さらには０.１〜０.２ｗｔ％である。この範囲では、特に優れた品質係数（Ｑ）を得ることができる。
【００６８】
次にＣｏ量に着目すると、Ｃｏ量が０.７５ｗｔ％以下（０を含まず）の範囲にある場合には、曲線ａ〜ｅは４０以上という優れた品質係数（Ｑ）を呈する。一方、Ｃｏ量が０.７５ｗｔ％を超えて１.０２０ｗｔ％になると、曲線ｃ〜ｅの品質係数（Ｑ）は４０以下となってしまう。また、曲線ａ〜ｅにおいて、Ｃｏ量が約０.６ｗｔ％のときには５０以上の非常に優れた品質係数（Ｑ）を示し、Ｃｏ量が０.２ｗｔ％のときに品質係数（Ｑ）のピーク値を得ていることがわかる。したがって、優れた品質係数（Ｑ）を得るためには、Ｃｏ量が０.７５ｗｔ％を超えないように焼結体中にＣｏを含めればよい。より望ましいＣｏ量は０.０５〜０.６ｗｔ％、さらには０.１〜０.４ｗｔ％である。
【００６９】
以上説明の通り、焼結体中に占めるＭｎ量を０.７５ｗｔ％以下（０を含まず）とし、かつＣｏ量を０.７５ｗｔ％以下（０を含まず）とすることにより、４０以上の優れた品質係数（Ｑ）を得ることができる。しかも、Ｍｎ量が０.０１〜０.６ｗｔ％およびＣｏ量が０.０５〜０.７５ｗｔ％である場合には、８０以上の優れた品質係数（Ｑ）を得ることも可能となる。また、Ｍｎ量が０.６ｗｔ％以上の場合にも、Ｃｏ量を０.０５〜０.６ｗｔ％とすることによって、５０以上の良好な品質係数（Ｑ）を得ることができる。
【００７０】
＜実施例の総合評価＞
本実施例により、焼結体中に占めるＭｎ量が０.７５ｗｔ％以下（０を含まず）であり、かつＣｏ量が０.７５ｗｔ％以下（０を含まず）の範囲において、優れた破壊電圧（ＶＢ），絶縁抵抗（ＩＲ），透磁率（μ）および品質係数（Ｑ）を得ることができることが明らかとなった。この範囲で特に優れた破壊電圧（ＶＢ），絶縁抵抗（ＩＲ）および品質係数（Ｑ）を得るためには、焼結体中に占めるＭｎ量を０.６ｗｔ％以下とすることが望ましい。また、焼結体中に占めるＭｎ量が０.６ｗｔ％以上の場合においても、Ｃｏ量を０.６ｗｔ％以下、さらには０.４ｗｔ％以下とすることによって、優れた破壊電圧（ＶＢ），絶縁抵抗（ＩＲ）および品質係数（Ｑ）を得ることが可能となる。さらにまた、焼結体中に占めるＭｎ量を０.２ｗｔ％以下とし、かつＣｏ量を０.６ｗｔ％以下とした場合には、特に優れた破壊電圧（ＶＢ），絶縁抵抗（ＩＲ）および品質係数（Ｑ）を得ることが可能となる。
【００７１】
以上、本実施例の破壊電圧（ＶＢ），絶縁抵抗（ＩＲ），透磁率（μ）および品質係数（Ｑ）の測定結果を示した。次に、加速寿命試験（ＨＡＬＴ）およびＣｕ偏析の面積率の測定結果を表１３に示す。試料としては、実施例ａにおけるＮｏ.１およびＮｏ.３、実施例ｃにおけるＮｏ.１６、実施例ｄにおけるＮｏ.２１、比較例１におけるＮｏ.３６を用いた。これらの粉末を用いて上記実施例と同様の条件により積層型コンデンサを作製し、加速寿命試験（ＨＡＬＴ）の測定を行なった。また、焼結体組織における元素分布を電子線プローブ・マイクロ・アナライザ（ＥＰＭＡ）によって観察し、焼結体組織に占めるＣｕ偏析の面積率を算出した。
［加速寿命試験（ＨＡＬＴ）］
作製した積層型チップコンデンサ４１に、１７５℃の高温下で８０Ｖの電圧を４８時間印加した後に不良となるか否か観察した。なお、観察したサンプルは、各々２０個である。
［ＥＰＭＡ測定条件、Ｃｕ偏析の面積率］
電子線プローブ・マイクロ・アナライザ（ＥＰＭＡ）として、日本電子(株)製のＪＣＭＡ７３３を用いて以下の条件で組織観察を行なった。また、この条件で測定した場合に、所定の測定点のカウント数が（測定点全体のカウント数の平均値×１.３倍）以上になったとき、その測定点をＣｕの偏析とし、Ｃｕの偏析の総数を全測定点の数で割って１００をかけた値を組織に占めるＣｕ偏析の面積率（Ｃｕ偏析率）とした。
Ｃｕ偏析の面積率（％）＝１００×（Ｃｕ偏析の点数）／（全測定点数）

【００７２】
【表１３】

【００７３】
Ｃｏ量が０.００６ｗｔ％であるＮｏ.１とＣｏ量が０.２００ｗｔ％であるＮｏ.３を対比すると、Ｎｏ.３において不良サンプル数が激減していることがわかる。Ｎｏ.１およびＮｏ.３は主成分の組成が同一であり、副成分としてのＭｎ量も０.０７０ｗｔ％と等しい。よって、不良サンプル数の激減には、Ｃｏ量が関係していることが明らかとなった。
Ｎｏ.３およびＮｏ.１６では、１７５℃の高温下で８０Ｖの電圧を１０時間印加した後においても不良サンプル数０と、良好な結果を示している。特に、Ｎｏ.１６では、４８時間印加した後においても不良サンプル数４と、極めて良好な結果を得ている。よって、ＮｉＣｕＺｎフェライトに副成分としてＭｎおよびＣｏを０.３〜０.５ｗｔ％ずつ添加し、Ｃｕ偏析率を６.０〜１０.０％の範囲とすることにより、非常に優れた耐久性を示す部品が得られることがわかった。またＮｏ.２１でも、１０時間印加した後の不良サンプル数１、２４時間印加した後の不良サンプル数７と良好な結果を得ている。一方、Ｍｎ量およびＣｏ量がともに０.７５ｗｔ％を超えているＮｏ.３６では、Ｎｏ.１と同レベルにまで不良サンプル数が増加してしまう。
以上の結果から、Ｍｎ量を０.７５ｗｔ％以下（０を含まず）とし、かつＣｏ量を０.０１〜０.７５ｗｔ％とすることにより、耐久性に非常に優れた部品が得られることがわかった。
【００７４】
さらに表１３には焼結体中に占めるＣｕ偏析の面積率（以下、Ｃｕ偏析率）も示してある。Ｃｕ偏析率が１.１％（Ｎｏ.３６）から５.２％（Ｎｏ.２１）まで増加すると不良サンプル数が激減する。そして、Ｃｕ偏析率が８.１％（Ｎｏ.１６）および１３.８％（Ｎｏ.３）においても不良サンプル数が少ないことがわかる。この結果から、Ｃｕ偏析率が本発明で推奨する所定の範囲、つまり１.５％〜１５.０％の範囲にあるときに耐久性に優れた部品が得られることがわかった。
次に、表１３のＣｕ偏析率の欄およびＭｎ量，Ｃｏ量の欄を対比して、Ｍｎ量とＣｕ偏析率との関係、Ｃｏ量とＣｕ偏析率との関係について述べる。Ｃｏ量が０.００６ｗｔ％であるＮｏ.１とＣｏ量が０.２００ｗｔ％であるＮｏ.３を対比すると、Ｎｏ.３のＣｕ偏析率の方が若干高い値となっている。Ｎｏ.１とＮｏ.３は主成分および副成分としてのＭｎ量が等しいから、Ｃｏ量の増加に伴ってＣｕ偏析率が上昇することがわかった。一方、主成分および副成分としてのＣｏ量が等しく、Ｍｎ量のみ異なるＮｏ.３（Ｍｎ量：０.０７０ｗｔ％）とＮｏ.２１（Ｍｎ量：０.５４４ｗｔ％）を対比すると、Ｎｏ.２１の方がＣｕ偏析率の値が低くなっている。この結果から、Ｍｎ量の増加に伴ってＣｕ偏析率が低下することがわかった。
【００７５】
また表１３において、Ｃｕ偏析率が１.１％の場合（Ｎｏ.３６）には破壊電圧（ＶＢ）が１.３９ｋＶであるのに対し、Ｃｕ偏析率が５.２％（Ｎｏ.２１）になると破壊電圧（ＶＢ）は２.７５ｋＶまで向上する。Ｃｕ偏析率が８.１％（Ｎｏ.１６）の場合もＣｕ偏析率が５.２％（Ｎｏ.２１）の場合とほぼ同じレベルの優れた破壊電圧（ＶＢ）を得ている。Ｃｕ偏析率が１３.８％の場合（Ｎｏ.３）には、破壊電圧（ＶＢ）は更に向上して３.０１ｋＶとなる。この傾向から、ＭｎおよびＣｏを所定量含み、かつＣｕ偏析率が１.５〜１５.０％の範囲にある場合に、破壊電圧（ＶＢ）の向上を図れることがわかった。また、この範囲で特に高い破壊電圧（ＶＢ）を得るためには、Ｃｕ偏析率は５.０〜１５.０％の範囲とすることが望ましい。
【００７６】
【発明の効果】
以上説明したように、本発明によれば従来に比して耐電圧性，耐久性に優れる磁性フェライト材料およびこれを用いた積層型フェライト部品を低コストで提供することができる。
【図面の簡単な説明】
【図１】 本実施の形態に係る積層型チップインダクタアレイの平面図である。
【図２】 図１のＡ−Ａ断面図である。
【図３】 図１のＢ−Ｂ断面図である。
【図４】 本実施の形態に係るＬＣ複合部品である。
【図５】 実施例で用いた積層型チップコンデンサの側断面図である。
【図６】 図５のＣ−Ｃ断面図である。
【図７】 本実施例で測定したＣｏ量による破壊電圧（ＶＢ）の変動を示すグラフである。
【図８】 本実施例で測定したＣｏ量による絶縁抵抗（ＩＲ）の変動を示すグラフである。
【図９】 本実施例で測定したＣｏ量による透磁率（μ）の変動を示すグラフである。
【図１０】 本実施例で測定したＣｏ量による品質係数（Ｑ）の変動を示すグラフである。
【符号の説明】
１…積層型チップインダクタアレイ、２…磁性フェライト層、３…内部電極、４…引出し電極、５…チップ体、６…外部電極、１１…ＬＣ複合部品、１２…チップコンデンサ部、１３…チップフェライト部、１５…外部電極、２１…セラミックス誘電体層、２２…内部電極、３２…磁性フェライト層、３３…電極層、４１…積層型チップコンデンサ、４２…磁性フェライト層、４３…内部電極、４４…チップ体、４５…外部電極[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a magnetic ferrite material and a multilayer ferrite component used for a multilayer chip ferrite component such as multilayer chip beads and multilayer inductors, and a composite multilayer component represented by an LC composite multilayer component.
[0002]
[Prior art]
A multilayer chip ferrite component and a composite multilayer component (collectively referred to as a multilayer ferrite component in the present specification) are used in various electric devices because of their small volume and high reliability. This laminated ferrite component is usually obtained by laminating and integrating a magnetic layer sheet or paste made of magnetic ferrite and an internal electrode paste by a thick film lamination technique, and then sintering the surface of the obtained sintered body. It is manufactured by printing or transferring a paste for an external electrode and baking it. In addition, sintering after laminating and integrating is called simultaneous sintering. Since Ag or Ag alloy is used as the material for the internal electrode due to its low resistivity, the magnetic ferrite material constituting the magnetic layer can be simultaneously sintered, in other words, below the melting point of Ag or Ag alloy. It is an absolute condition that sintering can be performed at a temperature (hereinafter sometimes referred to as “low temperature sintering”). Therefore, in order to obtain a laminated ferrite part having high density and high characteristics, the key is to sinter magnetic ferrite at a temperature below the melting point of Ag or an Ag alloy.
[0003]
NiCuZn ferrite is known as a magnetic ferrite that can be sintered at a temperature below the melting point of Ag or an Ag alloy. For example, JP-A-8-104561 discloses Fe as Fe.₂O_Three45.0 to 50.0 mol% converted to Ni, 5.0 to 10.0 mol% converted to NiO, 5.0 to 15.0 mol% converted to CuO, and Zn converted to ZnO 25.0 to 35.0 mol%, Mn to Mn_ThreeO_Four0.1 to 3.0 mol% in terms of Li and Li to Li₂A magnetic ferrite containing 0.01 to 3.0 mol% in terms of O is disclosed. JP-A-8-104562 discloses Fe as Fe.₂O_Three45.0 to 50.0 mol% converted to Ni, 15.0 to 30.0 mol% Ni converted to NiO, 8.0 to 15.0 mol% converted Cu to CuO, and Zn converted to ZnO 15.0 to 25.0 mol%, Mn to Mn_ThreeO_Four0.1 to 3.0 mol% in terms of Li and Li to Li₂A magnetic ferrite containing 0.01 to 3.0 mol% in terms of O is disclosed.
[0004]
[Problems to be solved by the invention]
Recently, in order to cope with high-density mounting, an example in which a plurality of internal electrodes are arranged in one laminated ferrite component has come out. In the multilayer ferrite component in which the plurality of internal electrodes are arranged, a potential difference (voltage) is generated between the internal electrodes, so that the ferrite material existing between the internal electrodes is required to have a withstand voltage. Here, the withstand voltage property indicates that when a voltage is generated in the ferrite component, the ferrite material can withstand a dielectric breakdown due to voltage application up to a higher voltage. However, the magnetic ferrite materials known so far have not been studied for such withstand voltage. Further, it is desirable that NiCuZn ferrite has durability and can be used suitably for a long time.
Accordingly, it is an object of the present invention to provide a magnetic ferrite material excellent in voltage resistance and durability and a laminated ferrite component using the same.
[0005]
[Means for Solving the Problems]
  The present inventor has studied to improve the voltage resistance and durability of the magnetic ferrite material. As a result, it was found that when Mn and Co are present in the sintered structure within a predetermined range, excellent voltage resistance and durability can be obtained. The present invention has been made based on the above findings,A laminated ferrite component having magnetic ferrite layers and internal electrodes alternately stacked and an external electrode electrically connected to the internal electrodes, wherein the magnetic ferrite layer is Fe ₂ O ₃ : 45.0 to 49.8 mol%, CuO: 7.0 to 25.0 mol%, ZnO: 15.0 to 30.0 mol% and NiO: 5.0 to 45.0 mol% as main components, Mn: 0 .75 wt% or less (excluding 0) and Co: 0.01 to 0.6 wt% as a subcomponent, and the segregation of Cu occupying the structure is 1.5 to 15.0% by area ratio. A laminated ferrite component comprising a bonded structure, wherein the internal electrode is composed of Ag or an Ag alloy.I will provide a.
  Of the present inventionMultilayer ferrite partsIn this case, it is desirable that the amount of Mn in the structure is 0.6 wt% or less (excluding 0) in terms of Mn. By including Mn in this range, a very excellent breakdown voltage (Vb) of 40 V or more per 1 μm of magnetic ferrite layer between conductors having a potential difference can be obtained. The present inventionMultilayer ferrite partsIn this case, when the amount of Mn in the structure is 0.2 wt% or less (excluding 0) in terms of Mn, a very good breakdown voltage (45 V or more per 1 μm of magnetic ferrite layer between conductors having a potential difference) Vb) can be obtained.
[0006]
  Furthermore, the present inventionMultilayer ferrite partsInOf the magnetic ferrite layerThe segregation of Cu in the structure is 1.5 to 15.0% in terms of area ratio. This is based on the knowledge that excellent voltage resistance can be obtained when Cu segregation is present in the sintered structure within a predetermined range. In addition, the calculation method of the area ratio of Cu segregation in this invention shall be specified by the calculation method employ | adopted in the Example mentioned later.
[0007]
The multilayer ferrite component of the present invention has an excellent voltage resistance of a breakdown voltage of 30 V or more per 1 μm of magnetic ferrite layer between conductors having a potential difference. Note that the breakdown voltage (Vb) in the present invention is specified based on the breakdown voltage measurement method employed in the examples described later. The multilayer ferrite component of the present invention has a characteristic that the quality factor (Q) is 40 or more. In addition, the quality factor (Q) in this invention shall be specified by the measuring method of the quality factor employ | adopted in the Example mentioned later. The present invention is preferably applied to a multilayer ferrite component having a plurality of independent internal electrodes. This is because if there are a plurality of internal electrodes, a potential difference occurs between the internal electrodes, which may lead to dielectric breakdown.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
  First, the reasons for limiting the composition in the present invention will be described.
  Fe₂O₃The amount of has a great influence on the magnetic permeability. Fe₂O₃But45.0If it is less than mol%, the magnetic permeability is small, and the magnetic permeability increases as it approaches the stoichiometric composition as ferrite, but rapidly decreases with the stoichiometric composition as a peak. Therefore, the upper limit is 49.8 mol%. Desirable Fe₂O₃Is 49.2 to 49.8 mol%.
  CuO is a compound that contributes to reducing the sintering temperature in the present invention,7.0If it is less than mol%, sintering in a temperature range below the melting point of Ag cannot be realized. However,25.0 molIf it exceeds 50%, the resistivity of ferrite will decrease and the quality factor Q will deteriorate.7.0 to 25.0mol%. The desired amount of CuO is10.0-20.0mol%.
[0009]
  ZnO can improve the magnetic permeability μ as the amount thereof increases, but if it is too large, the Curie temperature becomes 100 ° C. or lower, and the temperature characteristics required for electronic parts cannot be satisfied. Therefore, the amount of ZnO is15.0-30.0mol%. Desirable amount of ZnO18.0-25.0mol%. The amount of NiO is 5.0-45.0 mol%, and the desirable amount of NiO is7.0 to 35.0mol%.
  The magnetic properties of the magnetic ferrite are very composition-dependent, and in a region outside the above composition range, the magnetic permeability μ and the quality factor Q are low, making it unsuitable as a magnetic material for multilayer ferrite parts.
[0010]
  Next, the magnetic ferrite material according to the present invention contains Mn and Co as subcomponents. The amount of Mn is 0.75 wt% or less (excluding 0) in terms of Mn, and the amount of Co is in terms of Co.0.01-0.6wt%. This is because it has been found that when Mn and Co are in this range, the voltage resistance and durability are excellent and the quality factor Q is improved. By including Co in such a range, the multilayer ferrite component of the present invention has a breakdown voltage of 30 V or more per 1 μm of the magnetic ferrite layer, and can obtain a quality factor Q of 40 or more. The amount of Mn is preferably 0.6 wt% or less (excluding 0) in terms of Mn. Mn is within this range, and the amount of Co is 0.01 to0 . 6When it is wt%, a very excellent breakdown voltage (Vb) of 40 V or more per 1 μm of the magnetic ferrite layer between conductors having a potential difference can be obtained. Further, by setting the amount of Mn to 0.2 wt% or less (excluding 0) in terms of Mn and the amount of Co to 0.01 to 0.6 wt%, the magnetic ferrite layer 1 μm between conductors in which a potential difference has occurred. It is possible to obtain a very excellent breakdown voltage (Vb) of 45 V or more per unit. Here, “in terms of Mn” means the amount contained as pure Mn regardless of the form present in the sintered body. For example, even when it is contained as a Mn oxide, it does not refer to the amount of Mn oxide but to the amount of Mn constituting the Mn oxide. Similarly, “in terms of Co” refers to the amount contained as pure Co regardless of the form present in the sintered body.
[0011]
Next, in the magnetic ferrite sintered body according to the present invention, the segregation of Cu in the structure is 1.5 to 15.0% by area ratio. This is because when the segregation of Cu is within this range, it has been found that the voltage resistance and durability are excellent. A desirable area ratio of Cu segregation is 5.0 to 15.0%. By adopting such a Cu segregation structure, the multilayer ferrite component of the present invention can have a breakdown voltage of 30 V or more per 1 μm of the magnetic ferrite layer, and obtain an excellent insulation resistance (IR) of 5000 MΩ or more. Can do.
Several methods can be employed to reduce the segregation of Cu in the structure to a range of 1.5 to 15.0% in terms of area ratio. The amount of Cu segregation can be varied by controlling the amount of Mn and Co contained therein. As the amount of Mn increases, the amount of Cu segregation decreases, while as the amount of Co increases, the amount of Cu segregation increases. Therefore, by controlling one of the Mn amount or the Co amount, or by controlling both the Mn amount and the Co amount, the segregation of Cu in the structure is in the range of 1.5 to 15.0% in area ratio. Is possible. In that case, the amount of Mn is desirably 0.75 wt% or less (excluding 0) in terms of Mn. When the amount of Mn exceeds 0.75 wt%, it becomes difficult to ensure the area ratio of Cu segregation required by the present invention even if the amount of Co is increased.
[0012]
The magnetic ferrite material according to the present invention comprises a mixing step of mixing raw material powder, a calcining step of calcining the mixed raw material powder, and a calcined powder obtained by crushing the calcined body obtained by the calcining step. It can be obtained by a pulverization step to be obtained, a molding step for obtaining a molded body using the pulverized powder obtained by the pulverization step, and a sintering step for sintering the molded body obtained by the molding step.
As raw material powder, Fe₂O_ThreePowder, CuO powder, ZnO powder and NiO powder are prepared. These powders are the main constituents of the magnetic ferrite material having excellent voltage resistance according to the present invention. In addition to the powders forming these main components, raw material powders for Mn and Co, which are subcomponents, are prepared. For Mn, a Mn oxide (eg, Mn₂O_Three, Mn_ThreeO_Four) Or Mn carbonate (eg MnCO_Three) Is a raw material powder. However, this is only one aspect, and if Mn is contained in the sintered body in an amount of 0.75 wt% or less (not including 0) in terms of Mn, the addition is not limited. As for Co, a Co oxide (for example, CoO, Co_ThreeO_Four) Or Co carbonate (eg, CoCO_ThreeHowever, the raw material powder is not limited to this, and it is sufficient that Co is contained in the sintered body in an amount of 0.75 wt% or less (excluding 0) in terms of Co.
What is necessary is just to select the particle diameter of each raw material powder to prepare suitably in the range of 0.1-10 micrometers. The prepared raw material powder is wet-mixed using, for example, a ball mill. The mixing depends on the operating conditions of the ball mill, but a uniform mixed state can be obtained if it is carried out for about 20 hours.
[0013]
After mixing the raw material powder, calcining is performed. The temperature of calcination shall be 850 degrees C or less. That is, if the calcining temperature exceeds 850 ° C., the calcined body becomes hard, and it becomes difficult to obtain a particle size distribution of powder that enables sintering in a temperature range below the melting point of Ag. A desirable calcining temperature is 650 to 750 ° C. The calcining time may be appropriately selected within a range of 5 to 15 hours.
The calcined body is pulverized after the calcining. The specific surface area of the ground powder is 6m²/ G or more is important for sintering in a temperature range below the melting point of Ag. In order to obtain such a fine powder, the pulverization conditions may be controlled. However, the powder having such a particle size distribution can be collected from the pulverized powder without particularly controlling the conditions. When a ball mill is used, pulverization takes about 60 to 80 hours.
After adding a binder or the like to the pulverized powder obtained above, it is molded into a predetermined shape, and then subjected to sintering.
[0014]
Next, the multilayer ferrite component of the present invention will be described taking the multilayer chip inductor array 1 as an example. 1 to 3 are views showing a multilayer chip inductor array 1. FIG. 1 is a plan view thereof, FIG. 2 is a sectional view taken along line AA in FIG. 1, and FIG. 3 is a sectional view taken along line BB in FIG. . As shown in FIGS. 1 to 3, the multilayer chip inductor array 1 includes a multilayer chip body 5 in which magnetic ferrite layers 2 and internal electrodes 3 are alternately stacked, and internal parts at both ends of the chip body 5. It is composed of an electrode 3 and an external electrode 6 arranged so as to be electrically connected via the extraction electrode 4. The multilayer chip inductor array 1 includes four independent internal electrodes 3 in one chip body 5. When the plurality of internal electrodes 3 are provided in this way, a potential difference is generated between the adjacent internal electrodes 3 during use, so that withstand voltage is required. That is, when the present invention is applied to a laminated ferrite component having a plurality of independent internal electrodes 3, the effect can be fully enjoyed.
The magnetic ferrite material according to the present invention is used for the magnetic ferrite layer 2. That is, the magnetic ferrite powder having a predetermined composition is kneaded with the binder and the solvent to obtain a paste for forming the magnetic ferrite layer 2. This paste and paste for forming the internal electrode 3 and the extraction electrode 4 are alternately printed and laminated, and then sintered to obtain an integrated chip body 5.
As the binder, known binders such as ethyl cellulose, acrylic resin, butyral resin can be used. As the solvent, known solvents such as terpineol, butyl carbitol, kerosene, etc. can be used. There is no restriction | limiting in the addition amount of a binder and a solvent. However, it is recommended that the binder is in the range of 1 to 5 parts by mass and the solvent is in the range of 10 to 50 parts by mass.
In addition to the binder and the solvent, a dispersant, a plasticizer, a dielectric, an insulator and the like can be added in a range of 10 parts by mass or less. As a dispersant, sorbitan fatty acid ester and glycerin fatty acid ester can be added. As the plasticizer, dioctyl phthalate, dibutyl phthalate, butyl butyl phthalyl glycolate can be added.
[0015]
The magnetic ferrite layer 2 can also be formed using a magnetic ferrite layer sheet. That is, the slurry having a predetermined composition according to the present invention is kneaded in a ball mill together with a binder mainly composed of polyvinyl butyral and a solvent such as toluene and xylene to obtain a slurry. This slurry can be applied onto a film such as a polyester film and dried by a doctor blade method, for example, to obtain a magnetic ferrite layer sheet. If this magnetic ferrite layer sheet is alternately laminated with the paste for the internal electrodes 3 and then sintered, a multilayered chip body 5 can be obtained. In addition, although there is no restriction | limiting in the quantity of a binder, it is recommended to set it as the range of 1-5 mass parts. Moreover, a dispersing agent, a plasticizer, a dielectric material, an insulator, etc. can also be added in 10 mass parts or less.
[0016]
The internal electrode 3 is desirably made of Ag or an Ag alloy having a low resistivity, such as an Ag—Pd alloy, in order to obtain a practical quality factor Q as an inductor. However, the present invention is not limited to this, and Cu, Pd, or an alloy thereof can also be used. The paste for obtaining the internal electrode 3 can be obtained by mixing and kneading Ag or an Ag alloy powder, or an oxide powder thereof, a binder and a solvent. As a binder and a solvent, the thing similar to what was used for the paste for forming the said magnetic ferrite layer 2 is applicable. Each layer of the internal electrode 3 has an oval shape, and each layer of the internal electrode 3 adjacent in the thickness direction is spiraled to ensure conduction, so that a closed magnetic circuit coil (winding pattern) is formed.
As the material of the external electrode 6, a known material such as Ag, Ni, Cu, or an Ag—Pd alloy can be used. The external electrode 6 can be formed of these materials by various methods such as printing, plating, vapor deposition, ion plating, and sputtering.
[0017]
There is no particular limitation on the dimensions of the chip body 5 of the multilayer chip inductor array 1. It can set suitably according to a use. In general, the outer shape is substantially a rectangular parallelepiped shape, and many dimensions are in the range of 1.0 to 4.5 mm × 0.5 to 3.2 mm × 0.6 to 1.9 mm. Further, the interelectrode thickness and the base thickness of the magnetic ferrite layer 2 are not particularly limited, and the interelectrode thickness can be set to about 10 to 100 μm, and the base thickness can be set to about 250 to 500 μm. Furthermore, the thickness of the internal electrode 3 itself can usually be set in the range of 5 to 30 μm, the pitch of the winding pattern can be 10 to 100 μm, and the number of turns can be about 1.5 to 20.5 turns. .
[0018]
The sintering temperature after alternately laminating the paste or sheet for the magnetic ferrite layer 2 and the paste for the internal electrode 3 is 940 ° C. or lower. This is because if the temperature exceeds 940 ° C., the material constituting the internal electrode 3 diffuses into the magnetic ferrite layer 2 and the magnetic properties may be significantly deteriorated. Although the magnetic ferrite of the present invention is suitable for low temperature sintering, sintering is insufficient at temperatures below 800 ° C. Therefore, the sintering is desirably performed at 800 ° C. or higher. Desirable sintering temperature is 820-930 degreeC, More desirably, it is 875-920 degreeC. The sintering time may be set in the range of 0.05 to 5 hours, desirably 0.1 to 3 hours.
[0019]
Next, an LC composite component that is an embodiment of the LC composite multilayer component will be described. FIG. 4 is a schematic cross-sectional view of the LC composite component 11. As shown in FIG. 4, the LC composite component 11 is obtained by integrating a chip capacitor unit 12 and a chip ferrite unit 13.
The chip capacitor unit 12 has a multilayer laminated structure in which ceramic dielectric layers 21 and internal electrodes 22 are alternately laminated and integrated. There is a possibility that a potential difference occurs between the internal electrodes 22 to cause dielectric breakdown. There is no restriction | limiting in the material of the ceramic dielectric material layer 21, A conventionally well-known various dielectric material can be used. In the present invention, a titanium oxide-based dielectric having a low sintering temperature is desirable, but titanic acid-based composite oxide, zirconic acid-based composite oxide, or a mixture thereof can be used. Further, various glasses such as borosilicate glass may be added to lower the sintering temperature. As the internal electrode 22, the same material as that of the internal electrode 3 of the multilayer chip inductor array 1 described above can be used. Each internal electrode 22 is electrically connected to another external electrode 15 alternately.
[0020]
The chip ferrite portion 13 is composed of a multilayer chip inductor in which magnetic ferrite layers 32 and electrode layers 33 are alternately stacked. This basic configuration is the same as that of the multilayer chip inductor array 1 described above. Therefore, detailed description here is omitted.
The dimension of the LC composite component 11 is not limited as in the multilayer chip inductor array 1 described above. Therefore, it can be set appropriately according to the application. Usually, it has a substantially rectangular parallelepiped outer shape, and has dimensions of about 1.6 to 10.0 mm × 0.8 to 15.0 mm × 1.0 to 5.0 mm.
[0021]
[Example]
Hereinafter, the present invention will be described based on specific examples. In this example, Fe₂O_Three, CuO, ZnO and NiO as main components, and Mn as a minor component_ThreeO_FourThe experiment of 6 patterns (Examples a to e, Comparative Example 1) was tried by changing the CoO and CoO. Mn_ThreeO_FourIs expressed as wt% converted to Mn, and similarly CoO is displayed as wt% converted to Co.
<Example a (Sample Nos. 1 to 6)>
Mn_ThreeO_FourWas fixed at 0.070 wt%, and CoO was varied from 0.006 to 1.020 wt% (CoO: 0.006 wt%, 0.103 wt%, 0.200 wt%, 0.488 wt%, 0.700 wt%). , 1.020 wt%).
<Example b (Sample Nos. 7 to 12)>
Mn_ThreeO_FourWas fixed at 0.168 wt% (the variation amount of CoO is the same as in Example a).
<Example c (Sample Nos. 13 to 18)>
Mn_ThreeO_FourWas fixed at 0.357 wt% (the fluctuation amount of CoO is the same as in Example a).
<Example d (Sample Nos. 19 to 24)>
Mn_ThreeO_FourWas fixed at 0.544 wt% (the variation amount of CoO is the same as in Example a).
<Example e (Sample Nos. 25 to 30)>
Mn_ThreeO_FourWas fixed at 0.732 wt% (the variation amount of CoO is the same as in Example a).
<Comparative Example 1 (Sample Nos. 31 to 36)>
Mn_ThreeO_FourWas fixed at 1.028 wt% (CoO variation was the same as in Example a).
[0022]
The experimental results of Examples a to e and Comparative Example 1 are shown below.
<Example a>
Six types of pulverized powders shown in Table 1 were obtained according to the following mixing and pulverizing conditions. In Table 1, Fe₂O_Three, CuO, ZnO and NiO are the main components, Mn_ThreeO_FourAnd CoO are subcomponents. The peak position of the particle size distribution of the pulverized powder is 0.6 μm. Using these powders, multilayer capacitors were produced under the following conditions, and breakdown voltage (VB) and insulation resistance (IR) were measured. Moreover, the measurement core was produced and the magnetic permeability (μ) and the quality factor (Q) were measured.
The measured results are shown in Table 2. FIG. 7 (curve a) shows a graph showing the fluctuation of the breakdown voltage (VB) depending on the Co amount, and FIG. 8 (curve a) shows a graph showing the fluctuation of the insulation resistance (IR) depending on the Co amount. FIG. 9 (curve a) shows a graph showing the variation of magnetic susceptibility (μ), and FIG. 10 (curve a) shows a graph showing the variation of quality factor (Q) depending on the amount of Co.
[0023]
[Mixing to grinding conditions]
Pot for mixing and grinding: Stainless steel ball mill pot
Mixing and grinding media: Steel balls
Mixing time: 16 hours
Temporary firing conditions: 700 ° C x 10 hours
Grinding time: 72 hours
[Specifications of multilayer capacitor]
To 100 parts by mass of each powder having the composition shown in Table 1, 2.5 parts by mass of ethyl cellulose and 40 parts by mass of terpineol were added and kneaded with three rolls to prepare a magnetic ferrite layer paste. On the other hand, 2.5 parts by mass of ethyl cellulose and 40 parts by mass of terpineol were added to 100 parts by mass of Ag having an average particle size of 0.8 μm, and the mixture was kneaded with three rolls to obtain an internal electrode paste. The magnetic ferrite layer paste and the internal electrode paste were alternately printed and laminated, and then sintered at 890 ° C. for 2 hours to obtain a multilayer chip capacitor 41. 5 and 6 show a multilayer chip capacitor 41. FIG. 5 is a side sectional view of the multilayer chip capacitor 41, and FIG. 6 is a sectional view taken along the line CC in FIG. As shown in FIGS. 5 and 6, the multilayer chip capacitor 41 includes a multilayer chip body 44 in which magnetic ferrite layers 42 and internal electrodes 43 are alternately stacked, and internal electrodes at both ends of the chip body 44. 43 and an external electrode 45 disposed so as to be electrically conductive. The dimensions of the multilayer chip capacitor 41 are 3.2 mm × 1.6 mm × 1.1 mm, the number of internal electrodes 43 is four, and the thickness of the magnetic ferrite layer 42 between the internal electrodes 43 adjacent in the stacking direction. The length d (see FIG. 6) was 60 μm. The external electrode 45 was formed by baking Ag at 600 ° C.
[0024]
[Breakdown voltage (VB)]
A voltage is continuously applied to the manufactured multilayer chip capacitor 41 at a speed of 100 V / sec. Using an automatic boost breakdown tester (THK-2011ADMP) manufactured by Tama Denki Co., Ltd. The breakdown voltage was measured.
[Insulation resistance (IR)]
The insulation resistance (IR) of the manufactured multilayer chip capacitor 41 was measured by applying a voltage of 10 V for 1 minute and 15 seconds using a resistance meter (HP4329A) manufactured by Hewlett-Packard Co., Ltd.
[Permeability (μ), Quality factor (Q)]
Using the 6 types of pulverized powders shown in Table 1, toroidal shaped sintered body samples were prepared. A copper wire (wire diameter 0.35 mm) was wound around this sample for 20 turns, and the inductance was measured using an LCR meter (HP4192A manufactured by Hewlett-Packard Co.) at a measurement frequency of 100 kHz and a measurement current of 0.2 mA. And magnetic permeability (micro | micron | mu) was calculated | required using the following formula. For the quality factor (Q), the real number μ ′ and the imaginary number μ ″ of the complex permeability were obtained and calculated by Q (quality factor) = μ ′ / μ ”.
Permeability μ = (le × L) / (μ₀× Ae × N²)
le: Magnetic path length L: Sample inductance
μ₀: Permeability of vacuum = 4π × 10^-7(H / m) Ae: Sample cross-sectional area
N: Number of turns of coil
[0025]
[Table 1]

[0026]
[Table 2]

[0027]
In Table 2 and FIG. 7 curve a, when the amount of Co in terms of Co in the sintered body (hereinafter referred to as Co amount) is 0.006 wt% (No. 1), the breakdown voltage (VB) is 1.81 kV. It shows a good value. When the amount of Co reaches 0.103 wt% (No. 2), the breakdown voltage (VB) increases to 2.96 kV, and when the amount of Co is 0.200 wt% (No. 3), the breakdown voltage (VB) further increases. It will improve to 3.01kV. Although the breakdown voltage (VB) gradually decreases with this value as a peak, when the Co amount is 0.488 wt% (No. 4), the breakdown voltage (VB) is 2.83 kV and the Co amount is 0.700 wt%. In (No. 5), the breakdown voltage (VB) is 2.66 kV, which is a good value. However, when the Co amount exceeds 0.700 wt% (No. 5), the breakdown voltage (VB) is significantly reduced. When the Co amount is 1.020 wt% (No. 6), the breakdown voltage (VB) Dropped to 1.75 kV.
[0028]
Further, Table 2 also shows a value obtained by dividing the breakdown voltage (VB) by the thickness d (60 μm) of the magnetic ferrite layer 42. Here, in the case of the multilayer chip capacitor 41, a potential difference is generated between the internal electrodes 43 adjacent in the stacking direction. Therefore, this value is a breakdown voltage (Vb = VB / d) per 1 μm of the magnetic ferrite layer 42 existing between conductors in which a potential difference occurs, and in Nos. 1 to 5, an excellent breakdown voltage (Vb ) Among these, it is noted that a particularly excellent breakdown voltage (Vb) of 40 V or higher is obtained in Nos. 2 to 5 and 45 V or higher is obtained in Nos. 2 to 4.
[0029]
In Table 2 and curve a in FIG. 8, the insulation resistance (IR) is also related to the amount of Co. When the amount of Co is 0.006 wt% (No. 1), the insulation resistance (IR) is 700 MΩ. When the Co amount is 0.103 wt% (No. 2) and the Co amount is 0.200 wt% (No. 3), the insulation resistance (IR) shows an excellent value of 10,000 MΩ or more. When the Co amount is 0.488 wt% (No. 4), the insulation resistance (IR) is 9250 MΩ, and when the Co amount is 0.700 wt% (No. 5), the insulation resistance (IR) is 6300 MΩ, both good. Although the value is shown, when the Co amount reaches 1.020 wt% (No. 6), the insulation resistance (IR) decreases to 1510 MΩ.
[0030]
Next, with reference to Table 2, curve a, and curve a, the correlation between the Co amount and the magnetic permeability (μ) and the Co amount and the quality factor (Q) of the sintered ferrite member according to Example a is shown. explain.
In Table 2 and FIG. 9 curve a, the best magnetic permeability (μ) is shown when the Co amount is 0.006 wt% (No. 1), and the Co amount is 0.103 wt% (No. 2), 0 The permeability (μ) gradually decreases as it increases to .200 wt% (No. 3). On the other hand, looking at Table 2 and FIG. 10 curve a, it can be seen that the quality factor (Q) is also related to the amount of Co. When the amount of Co is 0.006 wt% (No. 1), the quality factor (Q) is 40. When the Co amount is 0.103 wt% (No. 2) and when the Co amount is 0.200 wt% (No. 3), the quality factor (Q) shows an excellent value of 100 or more. With this value as a peak, the quality factor (Q) gradually decreases. When the Co amount is 0.488 wt% (No. 4), 94, and when the Co amount is 0.700 wt% (No. 5), 75. However, it still shows a good value. Further, when the amount of Co increased to 1.020 wt% (No. 6), the quality factor (Q) decreased to 50.
[0031]
<Example b>
Example b had the composition shown in Table 3 and produced a multilayer capacitor under the same production conditions as in Example a, and measured breakdown voltage (VB) and insulation resistance (IR). Moreover, the measurement core was produced and the magnetic permeability (μ) and the quality factor (Q) were measured.
The measured results are shown in Table 4. FIG. 7 (curve b) shows a graph showing the fluctuation of the breakdown voltage (VB) depending on the Co amount, and FIG. 8 (curve b) shows a graph showing the fluctuation of the insulation resistance (IR) depending on the Co amount. FIG. 9 (curve b) shows a graph showing variations in magnetic susceptibility (μ), and FIG. 10 (curve b) shows graphs showing variations in quality factor (Q) depending on the amount of Co.
[0032]
[Table 3]

[0033]
[Table 4]

[0034]
In Table 4 and FIG. 7 curve b, the breakdown voltage (VB) when the amount of Co in the sintered body is 0.006 wt% (No. 7) is 1.99 kV. When the amount of Co reaches 0.103 wt% (No. 8), the breakdown voltage (VB) increases to 2.91 kV, and when the amount of Co is 0.200 wt% (No. 9), the breakdown voltage (VB) further increases. It will improve to 2.96kV. In addition, when the Co amount is 0.488 wt% (No. 10) and when the Co amount is 0.700 wt% (No. 11), a good breakdown voltage (VB) of 2.0 kV or more is obtained. However, when the amount of Co was 1.020 wt% (No. 12), the breakdown voltage (VB) decreased to 1.79 kV.
[0035]
Further, Table 4 also shows a value obtained by dividing the breakdown voltage (VB) by the thickness d (60 μm) of the magnetic ferrite layer 42, that is, the breakdown voltage per 1 μm of the magnetic ferrite layer 42 (Vb = VB / d). . Nos. 7 to 11 all have an excellent breakdown voltage (Vb) of 30 V or more. Of these, it is noted that Nos. 8 to 11 have a particularly excellent breakdown voltage (Vb) of 40 V or higher, and Nos. 8 to 10 have 45 V or higher.
[0036]
In Table 4 and curve b in FIG. 8, the insulation resistance (IR) is also related to the amount of Co. When the amount of Co is 0.006 wt% (No. 7), the insulation resistance (IR) is 1520 MΩ. When the amount of Co becomes 0.103 wt% (No. 8), the insulation resistance (IR) increases rapidly to 9500 MΩ, and when the amount of Co is 0.200 wt% (No. 9), the insulation resistance (IR) has a peak value. 9700 MΩ is shown. Even in the case where the Co amount is 0.488 wt% (No. 10) and the Co amount is 0.700 wt% (No. 11), the insulation resistance (IR) shows a good value of 5000 MΩ or more. However, when the Co content exceeded 0.700 wt% (No. 11), the insulation resistance (IR) rapidly decreased, and when the Co content was 1.020 wt% (No. 12), it decreased to 1430 MΩ.
[0037]
Next, using Table 4, curve b and curve 10 b, the correlation between the Co content and the magnetic permeability (μ) and the Co content and the quality factor (Q) of the sintered ferrite member according to Example b is shown. explain.
The curve b in FIG. 9 shows that the magnetic permeability (μ) gradually decreases as the amount of Co increases. On the other hand, FIG. 10 curve b shows that a very good quality factor (Q) can be obtained by setting the amount of Co within a predetermined range.
In Table 4, when the amount of Co is 0.006 wt% (No. 7), the permeability (μ) is 457 and the quality factor (Q) is 50, both of which are good values. It is noted that when the amount of Co becomes 0.103 wt% (No. 8), the magnetic permeability (μ) decreases to 300, but the quality factor (Q) increases to 100. When the Co amount is 0.200 wt% (No. 9), the Co amount is 0.488 wt% (No. 10), and the Co amount is 0.700 wt% (No. 11), the quality factor (Q ) Shows an excellent result of 60 or more. However, when the Co amount is 1.020 wt% (No. 12), the quality factor (Q) is lowered to a value equal to or less than the case where the Co amount is 0.006 wt% (No. 7).
[0038]
<Example c>
Example c was a composition shown in Table 5 and produced a multilayer capacitor under the same production conditions as Example a, and measured breakdown voltage (VB) and insulation resistance (IR). Moreover, the measurement core was produced and the magnetic permeability (μ) and the quality factor (Q) were measured.
The measured results are shown in Table 6. FIG. 7 (curve c) shows a graph showing the variation of the breakdown voltage (VB) due to the Co amount, and FIG. 8 (curve c) shows a graph showing the variation of the insulation resistance (IR) due to the Co amount. FIG. 9 (curve c) shows a graph showing variations in magnetic susceptibility (μ), and FIG. 10 (curve c) shows graphs showing variations in quality factor (Q) depending on the amount of Co.
[0039]
[Table 5]

[0040]
[Table 6]

[0041]
In Table 6 and FIG. 7 curve c, the breakdown voltage (VB) when the amount of Co in the sintered body is 0.006 wt% (No. 13) is 2.27 kV, which is a good value. When the Co content is 0.103 wt% (No. 14), the breakdown voltage (VB) is improved to 2.71 kV, and when the Co content is 0.200 wt% (No. 15), the breakdown voltage (VB) is further improved. 3.01 kV. With this value at the peak, the breakdown voltage (VB) gradually decreases. When the Co amount is 0.700 wt% (No. 17), it is 2.35 kV, and when the Co amount is 0.006 wt% (No. 13). To the same breakdown voltage (VB). Furthermore, when the amount of Co was 1.020 wt% (No. 18), the breakdown voltage (VB) decreased to 1.52 kV.
[0042]
Further, Table 6 also shows a value obtained by dividing the breakdown voltage (VB) by the thickness d (60 μm) of the magnetic ferrite layer 42, that is, the breakdown voltage per 1 μm of the magnetic ferrite layer 42 (Vb = VB / d). . Nos. 13 to 17 all have an excellent breakdown voltage (Vb) of 30 V or more. Among these, when the Co amount is 0.103 wt% (No. 14), the Co amount is 0.200 wt% (No. 15), and the Co amount is 0.488 wt% (No. 16). It is noted that both have obtained a very good breakdown voltage (Vb) of 40 V or higher.
[0043]
In Table 6 and curve c in FIG. 8, the insulation resistance (IR) is also related to the amount of Co. When the amount of Co is 0.006 wt% (No. 13), the insulation resistance (IR) is 3200 MΩ. When the Co content is 0.103 wt% (No. 14), the insulation resistance (IR) is improved to 8300 MΩ, and when the Co content is 0.200 wt% (No. 15), the insulation resistance (IR) is further improved. 9000 MΩ. However, when the amount of Co exceeds 0.700 wt% (No. 17), the insulation resistance (IR) rapidly decreases, and when the amount of Co is 1.020 wt% (No. 18), it decreases to 851 MΩ. .
[0044]
Next, with reference to Table 6, curve c, and curve 10 in FIG. 10, regarding the Co amount and permeability (μ) of the sintered ferrite member according to Example c, and the correlation between the Co amount and the quality factor (Q) explain. As shown in Table 6 and FIG. 9 curve c, the permeability (μ) is slightly reduced by adding Co, but in Nos. 13 to 17, the quality factor (Q) is a good value of 60 or more. (See Table 6 and curve c in FIG. 10). Among these, when the Co amount is 0.103 wt% (No. 14), the Co amount is 0.200 wt% (No. 15), and the Co amount is 0.488 wt% (No. 16). The quality factor (Q) is a particularly good value of 70 or more. However, when the Co content exceeds 0.700 wt% (No. 17), the quality factor (Q) is greatly reduced. When the Co content is 1.020 wt% (No. 18), the quality factor (Q ) Drops to 34.
[0045]
<Example d>
Example d was a composition shown in Table 7 and produced a multilayer capacitor under the same production conditions as in Example a, and measured breakdown voltage (VB) and insulation resistance (IR). Moreover, the measurement core was produced and the magnetic permeability (μ) and the quality factor (Q) were measured.
The measured results are shown in Table 8. FIG. 7 (curve d) shows a graph showing the fluctuation of the breakdown voltage (VB) depending on the Co amount, and FIG. 8 (curve d) shows a graph showing the fluctuation of the insulation resistance (IR) depending on the Co amount. FIG. 9 (curve d) shows a graph showing variations in magnetic susceptibility (μ), and FIG. 10 (curve d) shows graphs showing variations in quality factor (Q) depending on the amount of Co.
[0046]
[Table 7]

[0047]
[Table 8]

[0048]
In Table 8 and FIG. 7 curve d, No. 19 to 23 excluding the case where the amount of Co in the sintered body is 1.020 wt% (No. 24) shows a breakdown voltage (VB) of 2.0 kV or higher. ing. The breakdown voltage (VB) peaks when the amount of Co is 0.200 wt% (No. 21), and Nos. 20 to 22 have an excellent breakdown voltage (VB) of 2.5 kV or higher. .
Further, Table 8 also shows a value obtained by dividing the breakdown voltage (VB) by the thickness d (60 μm) of the magnetic ferrite layer 42, that is, the breakdown voltage per 1 μm of the magnetic ferrite layer 42 (Vb = VB / d). . Nos. 19 to 23 all have an excellent breakdown voltage (Vb) of 30 V or more. Among these, it is noted that Nos. 20 to 23 all obtain particularly excellent breakdown voltage (Vb) of 40 V or higher.
[0049]
In Table 8 and curve d in FIG. 8, the insulation resistance (IR) is also related to the amount of Co. When the amount of Co is 0.006 wt% (No. 19), the insulation resistance (IR) is 2630 MΩ. When the amount of Co becomes 0.103 wt% (No. 20), the insulation resistance (IR) rapidly increases to 7300 MΩ, and when the amount of Co is 0.200 wt% (No. 21), the insulation resistance (IR) further increases. It is improved to 8200MΩ. With this value as a peak, the insulation resistance (IR) gradually decreased. When the Co content was 1.020 wt% (No. 24), the insulation resistance (IR) decreased to 708 MΩ.
[0050]
Next, with reference to Table 8, curve d, and curve d in FIG. 10, the correlation between the Co amount and the magnetic permeability (μ) and the Co amount and the quality factor (Q) of the sintered ferrite member according to Example d. explain. As shown in Table 8 and FIG. 9 curve d, the magnetic permeability (μ) is slightly reduced by adding Co. On the other hand, as shown in Table 8 and curve d in FIG. Among them, the quality factors (Q) of Nos. 20 to 22 are particularly excellent values of 70 or more. However, when the Co amount is 1.020 wt% (No. 24), the quality factor (Q) is reduced to 38.
[0051]
<Example e>
Example e had a composition shown in Table 9 and produced a multilayer capacitor under the same production conditions as in Example a, and measured breakdown voltage (VB) and insulation resistance (IR). Moreover, the measurement core was produced and the magnetic permeability (μ) and the quality factor (Q) were measured.
The measured results are shown in Table 10. FIG. 7 (curve e) shows a graph showing the fluctuation of the breakdown voltage (VB) depending on the Co amount, and FIG. 8 (curve e) shows a graph showing the fluctuation of the insulation resistance (IR) depending on the Co amount. FIG. 9 (curve e) shows a graph showing variations in magnetic susceptibility (μ), and FIG. 10 (curve e) shows graphs showing variations in quality factor (Q) depending on the amount of Co.
[0052]
[Table 9]

[0053]
[Table 10]

[0054]
In Table 10 and FIG. 7 curve e, the breakdown voltage (VB) when the amount of Co in the sintered body is 0.006 wt% (No. 25) is 1.82 kV. When the amount of Co becomes 0.103 wt% (No. 26), the breakdown voltage (VB) increases to 2.32 kV, and when the amount of Co is 0.200 wt% (No. 27) and the amount of Co is 0.488 wt%. In the case (No. 28), a good breakdown voltage (VB) of 2.0 kV or higher is shown. However, when the Co content reached 1.020 wt% (No. 30), the breakdown voltage (VB) decreased to 1.45 kV.
[0055]
Further, Table 10 also shows a value obtained by dividing the breakdown voltage (VB) by the thickness d (60 μm) of the magnetic ferrite layer 42, that is, the breakdown voltage per 1 μm of the magnetic ferrite layer 42 (Vb = VB / d). . Nos. 25 to 29 all obtained an excellent breakdown voltage (Vb) of 30 V or more, whereas when the Co content is 1.020 wt% (No. 30), the breakdown voltage (Vb) is 24. Reduced to 2V.
[0056]
In Table 10 and curve e in FIG. 8, the insulation resistance (IR) is also related to the amount of Co. When the amount of Co is 0.006 wt% (No. 25), the insulation resistance (IR) is 728 MΩ. When the Co content is 0.103 wt% (No. 26), the insulation resistance (IR) is improved to 3980 MΩ, and when the Co content is 0.200 wt% (No. 27), the insulation resistance (IR) is further improved. 4310 MΩ. When the amount of Co exceeds 0.700 wt% (No. 29), the insulation resistance (IR) rapidly decreases, and when the amount of Co is 1.020 wt% (No. 30), it decreases to 417 MΩ.
[0057]
Next, with reference to Table 10, curve e, and curve e, the correlation between the Co content and the magnetic permeability (μ) and the Co content and the quality factor (Q) of the ferrite sintered member according to Example e is shown. explain. As shown in Table 10 and FIG. 9 curve e, the magnetic permeability (μ) is slightly decreased by adding Co, but in No. 25 to 29, the quality factor (Q) is a good value of 40 or more. Is shown. However, the quality factor (Q) decreased to 32 when the Co content was 1.020 wt% (No. 30).
[0058]
<Comparative Example 1>
Comparative Example 1 was a composition shown in Table 11 and produced a multilayer capacitor under the same production conditions as in Example a, and measured breakdown voltage (VB) and insulation resistance (IR). Moreover, the measurement core was produced and the magnetic permeability (μ) and the quality factor (Q) were measured.
The measured results are shown in Table 12. FIG. 7 (curve f) shows a graph showing the fluctuation of the breakdown voltage (VB) depending on the Co amount, and FIG. 8 (curve f) shows a graph showing the fluctuation of the insulation resistance (IR) depending on the Co amount. FIG. 9 (curve f) shows a graph showing variations in magnetic susceptibility (μ), and FIG. 10 (curve f) shows graphs showing variations in quality factor (Q) depending on the amount of Co.
[0059]
[Table 11]

[0060]
[Table 12]

[0061]
In FIG. 7, when the curves a to e according to the examples a to e are compared with the curve f according to the comparative example 1, it can be seen that the rate of increase of the breakdown voltage (VB) due to the addition of Co is hardly observed in the curve f.
8 to 10, the curve f according to Comparative Example 1 is at a lower level than the curves a to e in the insulation resistance (IR), the magnetic permeability (μ), and the quality factor (Q). It is clear.
[0062]
<Evaluation of Examples>
The measurement results of the breakdown voltage (VB), the insulation resistance (IR), the magnetic permeability (μ), and the quality factor (Q) of Examples a to e and Comparative Example 1 have been shown. Hereinafter, based on these results, an example is evaluated.
(1) Evaluation of breakdown voltage (VB)
First, the breakdown voltage (VB) is evaluated using FIG.
As shown in FIG. 7, the breakdown voltage (VB) is in the order of curves a to f. It is obvious that the curve f is at a lower level than the curves a to e. Here, the Mn amount of the curve a is 0.070 wt%, the Mn amount of the curve b is 0.168 wt%, the Mn amount of the curve c is 0.357 wt%, the Mn amount of the curve d is 0.544 wt%, and the Mn amount of the curve e The amount is 0.732 wt%, and the amount of Mn in the curve f is 1.028 wt%. Therefore, it was found that in order to obtain a good breakdown voltage (VB), the amount of Mn in the sintered body must be 0.75 wt% or less (excluding 0).
Further, in the curves a to e in which the amount of Mn is within the range recommended by the present invention, when the amount of Co in the sintered body exceeds 1.700 wt% and reaches 1.020 wt%, the breakdown voltage (VB) is 1. The voltage drops to 8 kV or less. From this tendency, in order to obtain an excellent breakdown voltage (VB), the amount of Mn in the sintered body is set to 0.75 wt% or less (not including 0), and the amount of Co in the sintered body is set to It has become clear that it is necessary to set the value within a predetermined range recommended in the present invention, that is, 0.75 wt% or less (not including 0).
[0063]
Next, the range in which a particularly excellent breakdown voltage (VB) can be obtained within the range recommended by the present invention for both the amount of Mn and the amount of Co in the sintered body will be examined.
Curves a to d obtain particularly good breakdown voltage (VB) when the amount of Co in the sintered body is in the range of 0.75 wt% or less. The curve a exhibits an excellent breakdown voltage (VB) of 2.5 kV or higher, and the curves b to d also obtain a breakdown voltage (VB) of 2.0 kV or higher over a wide range even if not as large as the curve a. It is noted that. Therefore, in order to obtain a particularly excellent breakdown voltage (VB), it is desirable that the Mn content in the sintered body is 0.6 wt% or less and the Co content is 0.75 wt% or less. A more desirable amount of Mn is 0.2 wt% or less. Moreover, since the favorable breakdown voltage (VB) is obtained in the curve a in which the amount of Mn is 0.070 wt%, a favorable breakdown voltage (VB) can be obtained if the amount of Mn is about 0.01 wt%. It is guessed. As for the amount of Co, since the curves a to d have peak values when the amount of Co is 0.2 wt%, the amount of Co is 0.05 to 0.6 wt%, and further 0.1 to 0.4 wt%. % Is desirable.
[0064]
Similarly to the curves a to d, the curve e also has a peak breakdown voltage (VB) when the Co content is 0.2 wt%, and shows an excellent value of about 2.5 kV. On the other hand, curves a to d show a breakdown voltage (VB) around 2.5 kV even when the Co amount is around 0.75 wt%, whereas curve e shows a breakdown when the Co amount reaches 0.700 wt%. The voltage (VB) becomes a value lower than 2.0 kV. From this tendency, when the amount of Mn in the sintered body is 0.6 wt% or more, the amount of Co is preferably 0.05 to 0.6 wt%, more preferably 0.1 to 0.4 wt%. When the amount of Mn in the sintered body is 0.6 wt% or more, an excellent breakdown voltage (VB) of 2.0 kV or more can be obtained by setting the Co amount to 0.05 to 0.6 wt%. it can.
[0065]
(2) Evaluation of insulation resistance (IR)
Next, the insulation resistance (IR) is evaluated using FIG.
As shown in FIG. 8, the insulation resistance (IR) is in the order of curves a to f. Similarly to the breakdown voltage (VB), the level of the insulation resistance (IR) of the curve f is low in the curves a to f. Therefore, it can be said that in order to obtain good insulation resistance (IR), the amount of Mn in the sintered body must be 0.75 wt% or less (excluding 0).
Further, in the curves a to e where both the amount of Mn and the amount of Co are recommended in the present invention, that is, 0.75 wt% or less, the curves a to d have good insulation resistance (IR). Among these, curves a and b have particularly good insulation resistance (IR). Therefore, by setting the amount of Mn in the sintered body to 0.6 wt% or less, more desirably 0.2 wt% or less, it is possible to obtain a very excellent insulation resistance (IR). However, since the effect cannot be enjoyed when the amount of Mn becomes too low, it is desirable to contain it in the range of 0.01 wt% or more, and further 0.03 wt% or more. Furthermore, since the peak value is obtained when the amount of Co in the sintered body is 0.2 wt%, the optimum range of the Co amount is 0.05 to 0.6 wt%. Can be said to be 0.01 to 0.4 wt%.
[0066]
(3) Evaluation of permeability (μ)
Next, the magnetic permeability (μ) is evaluated using FIG.
FIG. 9 shows that the curves a to e are at substantially the same level, and only the curve f is at a low level. Therefore, in order to obtain good magnetic permeability (μ), the amount of Mn in the sintered body may be 0.75 wt% or less (excluding 0).
Among the curves a to e, the curves c to e show particularly good magnetic permeability (μ), followed by the curves b and a. That is, it shows a tendency different from the breakdown voltage (VB) and the insulation resistance (IR) described above. From this tendency, it can be said that the desirable range of the Mn amount with respect to the magnetic permeability (μ) is 0.1 to 0.75 wt%, and further 0.3 to 0.75 wt%.
Furthermore, also in the curves a to e, in order to ensure a good magnetic permeability (μ) of 150 or more, the amount of Co in the sintered body is set to a range recommended by the present invention, that is, 0.75 wt% or less. It is desirable.
[0067]
(4) Evaluation of quality factor (Q)
Next, the quality factor (Q) is evaluated using FIG.
Referring to FIG. 10, the quality factor (Q) is also in the order of the curves a to f, and the quality factor (Q) of the curve f is 40 or less even at its peak value. Accordingly, it has been found that in order to obtain a good quality factor (Q) of 40 or more, the amount of Mn in the sintered body needs to be 0.75 wt% or less (excluding 0).
Curves a and b have particularly good quality factors (Q) among the curves a to e, and the curve e is at a lower level than the curves a to d. Therefore, in order to obtain a good quality factor (Q), Mn may be included so that the amount of Mn in the sintered body does not exceed 0.75 wt%. A more desirable amount of Mn is 0.1 to 0.6 wt%, and further 0.1 to 0.2 wt%. In this range, a particularly excellent quality factor (Q) can be obtained.
[0068]
Next, focusing on the Co content, when the Co content is in the range of 0.75 wt% or less (not including 0), the curves a to e exhibit an excellent quality factor (Q) of 40 or more. On the other hand, when the amount of Co exceeds 0.75 wt% and reaches 1.020 wt%, the quality factor (Q) of the curves c to e becomes 40 or less. Further, in the curves a to e, when the Co amount is about 0.6 wt%, a very excellent quality factor (Q) of 50 or more is shown, and when the Co amount is 0.2 wt%, the quality factor (Q) peak It can be seen that the value is obtained. Therefore, in order to obtain an excellent quality factor (Q), Co may be included in the sintered body so that the Co amount does not exceed 0.75 wt%. A more desirable amount of Co is 0.05 to 0.6 wt%, and further 0.1 to 0.4 wt%.
[0069]
As described above, when the amount of Mn in the sintered body is 0.75 wt% or less (excluding 0) and the amount of Co is 0.75 wt% or less (not including 0), 40 or more An excellent quality factor (Q) can be obtained. In addition, when the Mn amount is 0.01 to 0.6 wt% and the Co amount is 0.05 to 0.75 wt%, an excellent quality factor (Q) of 80 or more can be obtained. Further, even when the Mn amount is 0.6 wt% or more, a good quality factor (Q) of 50 or more can be obtained by setting the Co amount to 0.05 to 0.6 wt%.
[0070]
<Comprehensive evaluation of an Example>
According to this example, excellent fracture occurred when the amount of Mn in the sintered body was 0.75 wt% or less (excluding 0) and the amount of Co was 0.75 wt% or less (excluding 0). It became clear that voltage (VB), insulation resistance (IR), magnetic permeability (μ) and quality factor (Q) can be obtained. In order to obtain a particularly excellent breakdown voltage (VB), insulation resistance (IR) and quality factor (Q) in this range, it is desirable that the amount of Mn in the sintered body is 0.6 wt% or less. In addition, even when the amount of Mn in the sintered body is 0.6 wt% or more, by setting the Co amount to 0.6 wt% or less, and further to 0.4 wt% or less, an excellent breakdown voltage (VB), Insulation resistance (IR) and quality factor (Q) can be obtained. Furthermore, when the amount of Mn in the sintered body is 0.2 wt% or less and the amount of Co is 0.6 wt% or less, particularly excellent breakdown voltage (VB), insulation resistance (IR) and quality are obtained. The coefficient (Q) can be obtained.
[0071]
The measurement results of the breakdown voltage (VB), the insulation resistance (IR), the magnetic permeability (μ), and the quality factor (Q) of this example have been described above. Next, Table 13 shows the measurement results of the accelerated life test (HALT) and the area ratio of Cu segregation. As samples, No. 1 and No. 3 in Example a, No. 16 in Example c, No. 21 in Example d, and No. 36 in Comparative Example 1 were used. Using these powders, multilayer capacitors were produced under the same conditions as in the above examples, and the accelerated life test (HALT) was measured. The element distribution in the sintered body structure was observed with an electron beam probe microanalyzer (EPMA), and the area ratio of Cu segregation in the sintered body structure was calculated.
[Accelerated life test (HALT)]
It was observed whether or not a failure occurred after applying a voltage of 80 V to the manufactured multilayer chip capacitor 41 at a high temperature of 175 ° C. for 48 hours. Note that 20 samples were observed.
[EPMA measurement conditions, Cu segregation area ratio]
Using JCMA733 manufactured by JEOL Ltd. as an electron beam probe microanalyzer (EPMA), the structure was observed under the following conditions. Further, when measurement is performed under these conditions, when the count number of a predetermined measurement point becomes equal to or greater than (the average value of the count number of the entire measurement point × 1.3 times), the measurement point is defined as Cu segregation, and Cu A value obtained by dividing the total number of segregation by the number of all measurement points and multiplying by 100 was defined as the area ratio of Cu segregation (Cu segregation ratio) in the structure.
Cu segregation area ratio (%) = 100 × (Cu segregation score) / (total number of measurements)

[0072]
[Table 13]

[0073]
Comparing No. 1 with a Co amount of 0.006 wt% and No. 3 with a Co amount of 0.200 wt%, it can be seen that the number of defective samples is drastically reduced in No. 3. No. 1 and No. 3 have the same main component composition, and the amount of Mn as a subcomponent is also equal to 0.070 wt%. Therefore, it became clear that the amount of Co is related to the drastic decrease in the number of defective samples.
In No. 3 and No. 16, even after applying a voltage of 80 V at a high temperature of 175 ° C. for 10 hours, the number of defective samples is 0 and good results are shown. In particular, in No. 16, even after 48 hours of application, the number of defective samples was 4 and very good results were obtained. Therefore, by adding 0.3 to 0.5 wt% of Mn and Co as subcomponents to the NiCuZn ferrite and making the Cu segregation rate in the range of 6.0 to 10.0%, very excellent durability can be obtained. It turns out that the parts shown are obtained. In No. 21, the number of defective samples after applying for 10 hours, and the number of defective samples after applying for 24 hours, 7 and good results are obtained. On the other hand, in No. 36 in which both the amount of Mn and the amount of Co exceed 0.75 wt%, the number of defective samples increases to the same level as No. 1.
From the above results, it is possible to obtain a component with excellent durability by setting the Mn amount to 0.75 wt% or less (not including 0) and the Co amount to 0.01 to 0.75 wt%. I understood.
[0074]
Furthermore, Table 13 also shows the area ratio of Cu segregation in the sintered body (hereinafter referred to as Cu segregation ratio). As the Cu segregation rate increases from 1.1% (No. 36) to 5.2% (No. 21), the number of defective samples decreases drastically. It can be seen that the number of defective samples is small even when the Cu segregation rate is 8.1% (No. 16) and 13.8% (No. 3). From this result, it was found that a component having excellent durability can be obtained when the Cu segregation rate is in a predetermined range recommended in the present invention, that is, in a range of 1.5% to 15.0%.
Next, the relationship between the Mn amount and the Cu segregation rate and the relationship between the Co amount and the Cu segregation rate will be described by comparing the column of the Cu segregation rate and the columns of the Mn amount and the Co amount in Table 13. When No. 1 having a Co content of 0.006 wt% and No. 3 having a Co content of 0.200 wt% are compared, the Cu segregation rate of No. 3 is slightly higher. Since No. 1 and No. 3 had the same amount of Mn as the main component and subcomponent, it was found that the Cu segregation rate increased as the amount of Co increased. On the other hand, when No. 3 (Mn amount: 0.070 wt%) and No. 21 (Mn amount: 0.544 wt%), which have the same amount of Co as the main component and subcomponent and differ only in the amount of Mn, are compared, The value of Cu segregation rate is lower. From this result, it was found that the Cu segregation rate decreases as the amount of Mn increases.
[0075]
In Table 13, when the Cu segregation rate is 1.1% (No. 36), the breakdown voltage (VB) is 1.39 kV, whereas the Cu segregation rate is 5.2% (No. 21). Then, the breakdown voltage (VB) is increased to 2.75 kV. Even when the Cu segregation rate is 8.1% (No. 16), an excellent breakdown voltage (VB) of almost the same level as that obtained when the Cu segregation rate is 5.2% (No. 21) is obtained. When the Cu segregation rate is 13.8% (No. 3), the breakdown voltage (VB) is further improved to 3.01 kV. From this tendency, it was found that the breakdown voltage (VB) can be improved when a predetermined amount of Mn and Co is contained and the Cu segregation rate is in the range of 1.5 to 15.0%. In order to obtain a particularly high breakdown voltage (VB) within this range, it is desirable that the Cu segregation rate be in the range of 5.0 to 15.0%.
[0076]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a magnetic ferrite material excellent in voltage resistance and durability as compared with the conventional one and a laminated ferrite component using the same, at low cost.
[Brief description of the drawings]
FIG. 1 is a plan view of a multilayer chip inductor array according to an embodiment.
FIG. 2 is a cross-sectional view taken along the line AA of FIG.
3 is a cross-sectional view taken along the line BB in FIG.
FIG. 4 is an LC composite component according to the present embodiment.
FIG. 5 is a side sectional view of the multilayer chip capacitor used in the examples.
6 is a cross-sectional view taken along the line CC of FIG.
FIG. 7 is a graph showing the variation of breakdown voltage (VB) depending on the amount of Co measured in this example.
FIG. 8 is a graph showing variations in insulation resistance (IR) depending on the amount of Co measured in the present example.
FIG. 9 is a graph showing variation in magnetic permeability (μ) depending on the amount of Co measured in this example.
FIG. 10 is a graph showing the variation of the quality factor (Q) depending on the amount of Co measured in this example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Multilayer chip inductor array, 2 ... Magnetic ferrite layer, 3 ... Internal electrode, 4 ... Lead electrode, 5 ... Chip body, 6 ... External electrode, 11 ... LC composite component, 12 ... Chip capacitor part, 13 ... Chip ferrite 15 ... external electrode, 21 ... ceramic dielectric layer, 22 ... internal electrode, 32 ... magnetic ferrite layer, 33 ... electrode layer, 41 ... multilayer chip capacitor, 42 ... magnetic ferrite layer, 43 ... internal electrode, 44 ... Chip body, 45 ... external electrode

Claims (6)

A laminated ferrite component having magnetic ferrite layers and internal electrodes alternately laminated, and having external electrodes electrically connected to the internal electrodes,
The magnetic ferrite layer is _{Fe 2 O 3: 45.0~49.8 mol%} , CuO: 7.0~25.0 mol%, ZnO: 15.0~30.0 mol% and NiO: 5.0 to as main components 45.0 mol%, Mn: 0.75wt% or less (not including 0), and Co: 0.01 to 0.6 look including the wt% as an auxiliary component, the area segregation of Cu occupying the tissue It is composed of a magnetic ferrite sintered body having a rate of 1.5 to 15.0% ,
The multilayer ferrite component, wherein the internal electrode is made of Ag or an Ag alloy. The multilayer ferrite component according to claim 1, wherein Mn is contained as an auxiliary component in an amount of 0.6 wt% or less . The multilayer ferrite component according to claim 1, wherein Mn is contained as an auxiliary component in an amount of 0.2 wt% or less . The multilayer ferrite component according to any one of claims 1 to 3, wherein the breakdown voltage is 30 V or more per 1 µm of the magnetic ferrite layer between conductors having a potential difference. The multilayer ferrite component according to any one of claims 1 to 4, wherein the quality factor is 40 or more. The multilayer ferrite component according to any one of claims 1 to 5 , further comprising a plurality of independent internal electrodes.

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