JP3796771B2 - Non-reducing dielectric ceramic composition and multilayer ceramic capacitor using the same - Google Patents
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【０００１】
【発明の属する技術分野】
本発明は、非還元性誘電体磁器組成物とそれを用いた積層セラミックコンデンサに関する。
【０００２】
【従来の技術】
近年、積層コンデンサの需要がますます高まっている。積層セラミックコンデンサの製造工程では、まず、その表面に内部電極となる電極材料を塗布したシート状の誘電体材料が準備される。この電極材料を塗布したシート状の誘電体材料を積層して熱圧着し、一体化したものを自然雰囲気中において、１２５０〜１３５０℃で焼成することによって、内部電極を積層状に有する誘電体磁器が得られる。そして、この誘電体磁器の両端面に、内部電極と導通する外部電極を焼き付けて、積層セラミックコンデンサが得られる。
【０００３】
したがって、この内部電極材料としては、次のような条件を満たす必要がある。すなわち、
（ａ）誘電体材料と内部電極材料とが同時に焼成されるので、誘電体が焼結する温度以上の融点を有すること。
【０００４】
（ｂ）焼成時、酸化性の高温雰囲気中においても酸化されず、しかも誘電体と反応しないこと。
【０００５】
このような条件を満足する内部電極材料としては、白金、金、パラジウム、またはこれら合金等の貴金属が用いられていた。
【０００６】
しかしながら、これらの内部電極材料は優れた特性を有する反面、高価であった。そのため、積層セラミックコンデンサのコストに占める内部電極材料費の割合は３０〜７０％にも達し、製造コストを上昇させる最大の要因になっていた。
【０００７】
ところで、貴金属以外に高融点を持つものとして、Ｎｉ、Ｆｅ、Ｃｏ、Ｗ、Ｍｏ等の卑金属があるが、これらの卑金属は、高温の酸化性雰囲気中では容易に酸化されてしまい、誘電体と反応して、内部電極としての役目を果たさなくなってしまう。そのため、これらの卑金属を積層セラミックコンデンサの内部電極として使用するためには、誘電体材料とともに、中性または還元性雰囲気中で焼成する必要がある。ところが、従来の誘電体磁器組成物材料では、このような還元性雰囲気で焼成すると、著しく還元されて半導体化してしまうという欠点があった。
【０００８】
このような欠点を克服するために、例えば、特公昭５７−４２５８８号公報に示されるように、チタン酸バリウム固溶体において、バリウムサイトとチタンサイトの比を化学量論比より過剰にした誘電体材料が考え出された。この誘電体材料を使用することによって、還元性雰囲気で焼成しても半導体化しない誘電体磁器を得ることができ、内部電極材料としてニッケル等の卑金属を使用した積層セラミックコンデンサの製造が可能となった。
【０００９】
【発明が解決しようとする課題】
ところが、近年のエレクトロニクスの発展に伴い、積層セラミックコンデンサの絶縁破壊電圧の向上、及びバイアス特性の向上の重要性がますます高まっている。
【００１０】
例えば、特開昭６１−１０１４５９号公報に示されるように、チタン酸バリウム固溶体に、Ｙ2 Ｏ3 、Ｌａ2 Ｏ3 、Ｎｄ2 Ｏ3 、Ｄｙ2 Ｏ3 、Ｓｍ2 Ｏ3 、Ｇｄ2 Ｏ3 等の希土類酸化物を、０．２〜１．０ｗｔ％添加すると、結晶粒径の小さい非還元性誘電体磁器が得られることが知られている。しかしながら、絶縁破壊電圧、及びバイアス特性の更なる向上を図ろうとすると、結晶粒径をより一層小さく制御する必要がある。
【００１１】
それゆえに、本発明の主たる目的は、還元性雰囲気中で焼成しても半導体化せず、また、結晶粒径が小さいにもかかわらず大きな誘電率が得られ、かつ、絶縁破壊電圧が高く、バイアス特性が良好な非還元性誘電体磁器組成物、及びそれを用いた積層セラミックコンデンサを提供することにある。
【００１２】
【課題を解決するための手段】
本発明は上記目的を達成するためになされたものであり、請求項１において、非還元性誘電体磁器組成物は、主成分が、一般式（Ｂａ1-m Ｒｅm ）p （Ｔｉ1-n-o Ｚｒn Ｍｎo ）Ｏ3 （但し、ＲｅはＬａ、Ｃｅ、Ｐｒ、Ｎｄの中から選ばれる少なくとも１種類）で表され、ｍ、ｎ、ｏ及びｐが、それぞれ、０＜ｍ≦０．０５、０＜ｎ≦０．２０、０＜ｏ≦０．０３、１．０２０≦ｐ≦１．０３７を満足する非還元性誘電体磁器組成物に、該非還元性誘電体磁器組成物を１００重量部としたとき、ＢａＯ−ＳｒＯ−ＣａＯ−Ｌｉ2 Ｏ−ＳｉＯ2 を主成分とするガラスからなる副成分が、０．３〜２．５重量部添加されていることを特徴とするものである。
【００１３】
また、請求項２において、非還元性誘電体磁器組成物は、主成分が、一般式（Ｂａ1-l-m Ｃａl Ｒｅm ）p （Ｔｉ1-n-o Ｚｒn Ｍｎo ）Ｏ3 （但し、ＲｅはＬａ、Ｃｅ、Ｐｒ、Ｎｄの中から選ばれる少なくとも１種類）で表され、ｌ、ｍ、ｎ、ｏ及びｐが、それぞれ、０＜ｌ≦０．２０、０＜ｍ≦０．０５、０＜ｎ≦０．２０、０＜ｏ≦０．０３、１．０２０≦ｐ≦１．０３７を満足する非還元性誘電体磁器組成物に、該非還元性誘電体磁器組成物を１００重量部としたとき、ＢａＯ−ＳｒＯ−ＣａＯ−Ｌｉ2 Ｏ−ＳｉＯ2 を主成分とするガラスからなる副成分が、０．３〜２．５重量部添加されていることを特徴とするものである。
【００１４】
また、請求項３において、積層セラミックコンデンサは、複数の誘電体セラミック層と、該誘電体セラミック層を介して配置された複数の内部電極と、該内部電極に接続された外部電極とからなる積層セラミックコンデンサにおいて、前記誘電体セラミック層は、主成分が、一般式（Ｂａ1-m Ｒｅm ）p （Ｔｉ1-n-o Ｚｒn Ｍｎo ）Ｏ3 （但し、ＲｅはＬａ、Ｃｅ、Ｐｒ、Ｎｄの中から選ばれる少なくとも１種類）で表され、ｍ、ｎ、ｏ及びｐが、それぞれ、０＜ｍ≦０．０５、０＜ｎ≦０．２０、０＜ｏ≦０．０３、１．０２０≦ｐ≦１．０３７を満足する非還元性誘電体磁器組成物に、該非還元性誘電体磁器組成物を１００重量部としたとき、ＢａＯ−ＳｒＯ−ＣａＯ−Ｌｉ2 Ｏ−ＳｉＯ2 を主成分とするガラスからなる副成分が、０．３〜２．５重量部添加されている非還元性誘電体磁器組成物からなり、前記内部電極はニッケルを主成分として構成されていることを特徴とするものである。
【００１５】
また、請求項４において、積層セラミックコンデンサは、複数の誘電体セラミック層と、該誘電体セラミック層を介して配置された複数の内部電極と、該内部電極に接続された外部電極とからなる積層セラミックコンデンサにおいて、前記誘電体セラミック層は、主成分が、一般式（Ｂａ1-l-m Ｃａl Ｒｅm ）p （Ｔｉ1-n-o Ｚｒn Ｍｎo ）Ｏ3 （但し、ＲｅはＬａ、Ｃｅ、Ｐｒ、Ｎｄの中から選ばれる少なくとも１種類）で表され、ｌ、ｍ、ｎ、ｏ及びｐが、それぞれ、０＜ｌ≦０．２０、０＜ｍ≦０．０５、０＜ｎ≦０．２０、０＜ｏ≦０．０３、１．０２０≦ｐ≦１．０３７を満足する非還元性誘電体磁器組成物に、該非還元性誘電体磁器組成物を１００重量部としたとき、ＢａＯ−ＳｒＯ−ＣａＯ−Ｌｉ2 Ｏ−ＳｉＯ2 を主成分とするガラスからなる副成分が、０．３〜２．５重量部添加されている非還元性誘電体磁器組成物からなり、前記内部電極はニッケルを主成分として構成されていることを特徴とするものである。
【００１６】
【発明の実施の形態】
（実施例１）
まず、出発原料として、純度９９．８％以上のＢａＣＯ3 、ＣａＣＯ3 、Ｌａ2 Ｏ3 、ＣｅＯ2 、Ｎｄ2 Ｏ3 、Ｐｒ2 Ｏ3 、ＴｉＯ2 、ＺｒＯ2 、ＭｎＣＯ3と、ＢａＯ−ＳｒＯ−ＣａＯ−Ｌｉ2 Ｏ−ＳｉＯ2 を主成分とするガラスをそれぞれ準備した。
【００１７】
そして、これらの原料を、（Ｂａ1-m Ｒｅm ）p （Ｔｉ1-n-o Ｚｒn Ｍｎo ）Ｏ3 、または（Ｂａ1-l-m Ｃａl Ｒｅm ）p （Ｔｉ1-n-o Ｚｒn Ｍｎo ）Ｏ3 の組成式に対して、表１及び表２に示すｌ、ｍ、ｎ、ｏ、ｐの値になるように配合し、また、同時に、配合する前記磁器組成物を１００重量部としたとき、同じく表１及び表２に示すように、それぞれガラスを添加して各配合原料を得た。なお、表中、＊印を付したものは本発明の範囲外である。
【００１８】
【表１】
【表２】
この配合原料をボールミルで湿式混合し、粉砕した後乾燥し、空気中において１１００℃で２時間仮焼して仮焼物を得た。そして、この仮焼物を乾式粉砕機によって粉砕し、粒径が１μｍ以下の粉砕物を得た。
【００２１】
次に、これら混合粉砕物のそれぞれにポリビニルブチラール系バインダー、及びエタノール等の有機溶剤を加えて、ボールミルにより湿式混合し、セラミックスラリーを調製した。
【００２２】
その後、これらのセラミックスラリーをドクターブレード法によりシート状に成形し、厚み２０μｍの矩形のセラミックグリーンシートを得た。次に、このセラミックグリーンシート上に内部電極を形成するために、Ｎｉを主成分とする導電ペーストを印刷パターンを用いて印刷した。その後、内部電極層が形成されたセラミックグリーシートを、内部電極の引き出されている側が互い違いとなるように、複数枚積層して積層体を得た。
【００２３】
得られた積層体を、空気中において３００℃まで加熱して有機バインダーを燃焼させた後、酸素分圧が２×１０-10 〜３×１０-12 ＭＰａのＨ2 −Ｎ2 −Ｏ2混合ガスからなる還元雰囲気炉中において、表３及び表４に示す温度で２時間焼成して、セラミック焼結体を得た。なお、表中、＊印を付したものは本発明の範囲外である。
【００２４】
【表３】
【表４】
次に、得られたセラミック焼結体の破断面をエッチングした。そのエッチング面を、走査型電子顕微鏡を用いて倍率１５００倍で観察し、グレインサイズを測定した。この結果を同じく表３及び表４に示す。
【００２７】
その後、このセラミック焼結体の内部電極が引き出された両端面に、Ａｇ電極ペーストを塗布し、大気中で８００℃の温度で焼き付け、内部電極に電気的に接続された外部電極を形成した。
【００２８】
以上のようにして得られた積層セラミックコンデンサの外径寸法は、幅１．６ｍｍ、長さ３．２ｍｍ、厚み１．２ｍｍであり、内部電極間の誘電体セラミック層の厚みは１５μｍであった。また、有効誘電体セラミック層の総数は１０であり、１層あたりの内部電極の対向面積は２．１ｍｍ2 であった。
【００２９】
次に、このようにして得られた積層セラミックコンデンサの誘電率（ε）、誘電正接（ｔａｎδ）、静電容量の温度変化率（ＴＣＣ）、絶縁抵抗を測定するとともに、絶縁破壊電圧（ＢＤＶ）、及びバイアス特性を評価した。なお、誘電率及び誘電正接は温度２０℃、１ＫＨｚ、１Ｖｒｍｓの条件で測定した。また、温度変化に対する静電容量の変化率については、２０℃での静電容量を基準とした−２５℃と８５℃での変化率（ΔＣ／Ｃ20）、及び−２５〜８５℃の範囲内での変化率が、２０℃での静電容量を基準としてプラス側で最大の値（ΔＣ／Ｃ20ｍａｘ）を求めた。また、絶縁抵抗は２５℃及び８５℃において、２５Ｖの直流電圧を２分間印加して、絶縁抵抗計で測定した後、体積抵抗率の対数（ｌｏｇρ）を算出した。また、絶縁破壊電圧は，１０個の積層コンデンサを絶縁油に浸漬した状態で、コンデンサの両電極間に１００Ｖ／ｍｉｎの一定の昇圧速度で電圧を印加して行き、破壊に至った電圧を絶縁破壊電圧として測定した。また、バイアス特性は、１０個の積層セラミックコンデンサに、１ｋＨｚ、１Ｖｒｍｓの交流電圧を印加し、そこに電界強度１ｋＶ／ｍｍの直流電圧を重畳させて、静電容量の変化率を確認した。
【００３０】
以上の各試験の結果を表３及び表４に示す。
【００３１】
表３及び表４に示すとおり、本発明の非還元性誘電体磁器組成物は、誘電率が８０００以上と高く、誘電正接は０．５％以下で、温度に対する静電容量の変化率が−２５〜８５℃の範囲でＪＩＳ規格に規定するＦ特性を満足する。しかも、セラミック焼結体のグレインサイズは２．５μｍ以下と小さく、２５℃及び８５℃における体積抵抗率はｌｏｇρで１２．０Ωｃｍ以上と高い。そして、絶縁破壊電圧が約１２ｋＶ／ｍｍと比較的高く、また、バイアス特性は、ＤＣ電界強度が１ｋＶ／ｍｍのときに、ΔＣが約−５０％と比較的小さいことが確認できた。
【００３２】
次に、本発明の各組成範囲を限定した理由について説明する。
【００３３】
（Ｂａ1-l-m Ｃａl Ｒｅm ）p （Ｔｉ1-n-o Ｚｒn Ｍｎo ）Ｏ3 において、０＜ｌ≦０．２０としたのは、試料番号１のように、Ｃａ添加量ｌが０．２０を超えると、焼結不良となり好ましくない。
【００３４】
また、０＜ｍ≦０．０５としたのは、試料番号２のように、Ｎｄ添加量ｍが０．０５を超える場合、焼結磁器が半導体化し好ましくない。また、試料番号３のように、Ｌａ添加量ｍが０．０５を超える場合も、焼結磁器が半導体化し好ましくない。同様に、試料番号４のように、Ｐｒ添加量ｍが０．０５を超える場合も、焼結磁器が半導体化し好ましくない。そして、試料番号２８のように、希土類元素添加量ｍが０の場合、グレインサイズが５．０μｍまで大きくなり、また、ＢＤＶ値が８．３ｋＶ／ｍｍまで低下し好ましくない。
【００３５】
次に、０＜ｎ≦０．２０としたのは、試料番号２０のように、Ｚｒ添加量ｎが０の場合は、誘電率εが６１００と小さくなり、バイアス特性も−７２％と低下して好ましくない。また、試料番号２１のように、Ｚｒ添加量ｎが０．２０を超える場合は、誘電率εが６３００と小さくなり好ましくない。
【００３６】
次に、０＜ｏ≦０．０３としたのは、試料番号２２のように、Ｍｎ添加量ｏが０の場合は、焼結磁器が半導体化し好ましくない。また、試料番号２３のように、Ｍｎ添加量ｏが０．０３を超える場合は、焼結不良となり好ましくない。
【００３７】
次に、１．０２０≦ｐ≦１．０３７としたのは、試料番号２４のように、モル比ｐが１．０２０を下回る場合は、焼結不良となり好ましくない。また、試料番号２５のように、モル比ｐが１．０３７を超える場合も、焼結不良となり好ましくない。
【００３８】
そして、この非還元性誘電体磁器組成物を１００重量部としたとき、ガラスを０．３〜２．５重量部としたのは、試料番号２６のように、ガラス添加量が０．３重量部を下回る場合は、焼結不良となり好ましくない。また、試料番号２７のように、ガラス添加量が２．５重量部を超える場合は、グレインサイズが４．０μｍまで大きくなり、ＢＤＶ値が９．０ｋＶ／ｍｍまで低下し好ましくない。
【００３９】
なお、本実施例では、出発原料としてＢａＣＯ3 、ＣａＣＯ3 、Ｌａ2 Ｏ3 、ＣｅＯ2 、Ｎｄ2 Ｏ3 、Ｐｒ2 Ｏ3 、ＴｉＯ2 、ＺｒＯ2 、ＭｎＣＯ3 等の炭酸塩粉末または酸化物粉末を用いたが、これらの粉末に限定されるものではなく、アルコキシド法、共沈法または水熱合成法によって作製された粉末を用いてもよい。
【００４０】
【発明の効果】
本発明によれば、還元性雰囲気中で焼成しても還元されず、半導体化しない非還元性誘電体磁器組成物を得ることができる。したがって、この非還元性誘電体磁器組成物を用いた磁器で積層コンデンサを製造すれば、その内部電極材料として安価な卑金属を用いることができ、積層セラミックコンデンサのコストダウンを実現することができる。
【００４１】
また、この非還元性誘電体磁器組成物を用いた磁器では、従来の誘電体磁器組成物を用いた場合に比べて、その結晶粒径を十分に小さくできるにもかかわらず、大きな誘電率が得られる。したがって、小型で大容量の積層コンデンサを設計できる上に、絶縁破壊電圧が高くなり、かつ、バイアス特性が向上するという効果を奏することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a non-reducing dielectric ceramic composition and a multilayer ceramic capacitor using the same.
[0002]
[Prior art]
In recent years, the demand for multilayer capacitors has been increasing. In the manufacturing process of the multilayer ceramic capacitor, first, a sheet-like dielectric material is prepared by applying an electrode material to be an internal electrode on its surface. Dielectric porcelain having internal electrodes in a laminated state by laminating and thermocompression bonding the sheet-like dielectric material coated with this electrode material, and firing the integrated material in a natural atmosphere at 1250 to 1350 ° C. Is obtained. Then, external electrodes that are electrically connected to the internal electrodes are baked on both end faces of the dielectric ceramic, thereby obtaining a multilayer ceramic capacitor.
[0003]
Therefore, the internal electrode material must satisfy the following conditions. That is,
(A) Since the dielectric material and the internal electrode material are fired at the same time, they must have a melting point equal to or higher than the temperature at which the dielectric is sintered.
[0004]
(B) At the time of firing, it is not oxidized even in an oxidizing high-temperature atmosphere and does not react with the dielectric.
[0005]
As internal electrode materials satisfying such conditions, noble metals such as platinum, gold, palladium, and alloys thereof have been used.
[0006]
However, these internal electrode materials have excellent characteristics but are expensive. For this reason, the ratio of the internal electrode material cost to the cost of the multilayer ceramic capacitor has reached 30 to 70%, which has been the largest factor in increasing the manufacturing cost.
[0007]
By the way, there are base metals such as Ni, Fe, Co, W, and Mo as those having a high melting point in addition to the noble metals. However, these base metals are easily oxidized in a high-temperature oxidizing atmosphere. In response, it no longer serves as an internal electrode. Therefore, in order to use these base metals as internal electrodes of a multilayer ceramic capacitor, it is necessary to fire in a neutral or reducing atmosphere together with a dielectric material. However, the conventional dielectric porcelain composition material has a drawback that when it is fired in such a reducing atmosphere, it is significantly reduced to become a semiconductor.
[0008]
In order to overcome such drawbacks, for example, as shown in Japanese Patent Publication No. 57-42588, in a barium titanate solid solution, a dielectric material in which the ratio of barium sites to titanium sites is made larger than the stoichiometric ratio. Was conceived. By using this dielectric material, a dielectric ceramic that does not become a semiconductor even when fired in a reducing atmosphere can be obtained, and it becomes possible to manufacture a multilayer ceramic capacitor using a base metal such as nickel as an internal electrode material. It was.
[0009]
[Problems to be solved by the invention]
However, with the recent development of electronics, the importance of improving the dielectric breakdown voltage of a multilayer ceramic capacitor and improving the bias characteristics is increasing.
[0010]
For example, as disclosed in JP-A-61-101459, a barium titanate solid solution is mixed with Y 2 O 3 , La 2 O 3 , Nd 2 O 3 , Dy 2 O 3 , Sm 2 O 3 , Gd 2 O. It is known that when a rare earth oxide such as 3 is added in an amount of 0.2 to 1.0 wt%, a non-reducing dielectric ceramic having a small crystal grain size can be obtained. However, in order to further improve the dielectric breakdown voltage and bias characteristics, it is necessary to control the crystal grain size to be even smaller.
[0011]
Therefore, the main object of the present invention is not to make a semiconductor even when fired in a reducing atmosphere, and a large dielectric constant can be obtained despite the small crystal grain size, and the dielectric breakdown voltage is high, An object of the present invention is to provide a non-reducing dielectric ceramic composition having good bias characteristics and a multilayer ceramic capacitor using the same.
[0012]
[Means for Solving the Problems]
The present invention has been made to achieve the above object, and in claim 1, the non-reducing dielectric ceramic composition has a main component of the general formula (Ba 1-m Re m ) p (Ti 1- no Zr n Mn o ) O 3 (where Re is at least one selected from La, Ce, Pr and Nd), and m, n, o and p are 0 <m ≦ 0. 05, 0 <n ≦ 0.20, 0 <o ≦ 0.03, 1.020 ≦ p ≦ 1.037, and 100% of the non-reducing dielectric ceramic composition. when the weight part, in which auxiliary component composed of BaO-SrO-CaO-Li 2 O-SiO 2 glass whose main component, characterized in that it is added 0.3 to 2.5 parts by weight is there.
[0013]
Further, in claim 2, a non-reducing dielectric ceramic composition, the main component is represented by the general formula (Ba 1-lm Ca l Re m) p (Ti 1-no Zr n Mn o) O 3 ( where, Re Is represented by at least one selected from La, Ce, Pr and Nd), and l, m, n, o and p are 0 <l ≦ 0.20, 0 <m ≦ 0.05, 100 parts by weight of the non-reducing dielectric ceramic composition is added to the non-reducing dielectric ceramic composition satisfying 0 <n ≦ 0.20, 0 <o ≦ 0.03, 1.020 ≦ p ≦ 1.037. In this case, 0.3 to 2.5 parts by weight of a subcomponent made of glass mainly composed of BaO—SrO—CaO—Li 2 O—SiO 2 is added.
[0014]
The multilayer ceramic capacitor according to claim 3, wherein the multilayer ceramic capacitor includes a plurality of dielectric ceramic layers, a plurality of internal electrodes disposed via the dielectric ceramic layers, and an external electrode connected to the internal electrodes. in ceramic capacitors, the dielectric ceramic layer is a main component of the general formula (Ba 1-m Re m) p (Ti 1-no Zr n Mn o) O 3 ( where, Re is La, Ce, Pr, Nd M, n, o, and p are 0 <m ≦ 0.05, 0 <n ≦ 0.20, 0 <o ≦ 0.03, and 1, respectively. BaO—SrO—CaO—Li 2 O—SiO 2 is mainly added to the non-reducing dielectric ceramic composition satisfying 020 ≦ p ≦ 1.037 when the non-reducing dielectric ceramic composition is 100 parts by weight. Subcomponent made of glass as a component is 0.3- It is made of a non-reducing dielectric ceramic composition added by 2.5 parts by weight, and the internal electrode is mainly composed of nickel.
[0015]
The multilayer ceramic capacitor according to claim 4, wherein the multilayer ceramic capacitor includes a plurality of dielectric ceramic layers, a plurality of internal electrodes arranged via the dielectric ceramic layers, and an external electrode connected to the internal electrodes. in ceramic capacitors, the dielectric ceramic layer is a main component of the general formula (Ba 1-lm Ca l Re m) p (Ti 1-no Zr n Mn o) O 3 ( where, Re is La, Ce, Pr , Nd, and l, m, n, o, and p are 0 <l ≦ 0.20, 0 <m ≦ 0.05, and 0 <n ≦ 0. When the non-reducing dielectric ceramic composition satisfying 20, 0 <o ≦ 0.03 and 1.020 ≦ p ≦ 1.037 is 100 parts by weight of the non-reducing dielectric ceramic composition, BaO— gas mainly composed of SrO-CaO-Li 2 O- SiO 2 The sub-component made of a non-reducing dielectric ceramic composition to which 0.3 to 2.5 parts by weight is added, and the internal electrode is composed mainly of nickel It is.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Example 1
First, BaCO 3 , CaCO 3 , La 2 O 3 , CeO 2 , Nd 2 O 3 , Pr 2 O 3 , TiO 2 , ZrO 2 , MnCO 3 having a purity of 99.8% or more and BaO—SrO are used as starting materials. Glasses mainly containing —CaO—Li 2 O—SiO 2 were prepared.
[0017]
Then, these raw materials, (Ba 1-m Re m ) p (Ti 1-no Zr n Mn o) O 3 or, (Ba 1-lm Ca l Re m) p (Ti 1-no Zr n Mn o ) With respect to the composition formula of O 3 , it is blended so as to have values of l, m, n, o, and p shown in Tables 1 and 2, and at the same time, the ceramic composition to be blended is 100 parts by weight. As shown in Tables 1 and 2, glass was added to obtain each compounding raw material. In the table, those marked with * are outside the scope of the present invention.
[0018]
[Table 1]
[Table 2]
This blended raw material was wet-mixed with a ball mill, pulverized and dried, and calcined in air at 1100 ° C. for 2 hours to obtain a calcined product. The calcined product was pulverized by a dry pulverizer to obtain a pulverized product having a particle size of 1 μm or less.
[0021]
Next, a polyvinyl butyral binder and an organic solvent such as ethanol were added to each of these mixed pulverized products, and wet mixed by a ball mill to prepare a ceramic slurry.
[0022]
Thereafter, these ceramic slurries were formed into a sheet by a doctor blade method to obtain a rectangular ceramic green sheet having a thickness of 20 μm. Next, in order to form an internal electrode on the ceramic green sheet, a conductive paste containing Ni as a main component was printed using a printing pattern. Thereafter, a plurality of ceramic grease sheets with the internal electrode layers formed thereon were laminated so that the side from which the internal electrodes were drawn was staggered to obtain a laminate.
[0023]
The resulting laminate was allowed to burn organic binder was heated to 300 ° C. in air, H 2 -N 2 -O 2 mixture of oxygen partial pressure 2 × 10 -10 ~3 × 10 -12 MPa In a reducing atmosphere furnace made of gas, the ceramic sintered body was obtained by firing for 2 hours at the temperatures shown in Tables 3 and 4. In the table, those marked with * are outside the scope of the present invention.
[0024]
[Table 3]
[Table 4]
Next, the fracture surface of the obtained ceramic sintered body was etched. The etched surface was observed at a magnification of 1500 times using a scanning electron microscope, and the grain size was measured. The results are also shown in Tables 3 and 4.
[0027]
Thereafter, an Ag electrode paste was applied to both end faces from which the internal electrode of the ceramic sintered body was drawn, and baked at a temperature of 800 ° C. in the atmosphere to form an external electrode electrically connected to the internal electrode.
[0028]
The outer diameter of the multilayer ceramic capacitor obtained as described above was 1.6 mm in width, 3.2 mm in length, 1.2 mm in thickness, and the thickness of the dielectric ceramic layer between the internal electrodes was 15 μm. . The total number of effective dielectric ceramic layers was 10, and the opposing area of internal electrodes per layer was 2.1 mm 2 .
[0029]
Next, the dielectric constant (ε), dielectric loss tangent (tan δ), capacitance temperature change rate (TCC) and insulation resistance of the multilayer ceramic capacitor thus obtained were measured, and dielectric breakdown voltage (BDV) And bias characteristics were evaluated. The dielectric constant and dielectric loss tangent were measured under conditions of a temperature of 20 ° C., 1 KHz, and 1 Vrms. Moreover, about the change rate of the electrostatic capacitance with respect to the temperature change, the change rate (ΔC / C 20 ) at −25 ° C. and 85 ° C. based on the capacitance at 20 ° C., and the range of −25 to 85 ° C. The maximum value (ΔC / C 20 max) was obtained on the plus side, with the rate of change within the range on the basis of the capacitance at 20 ° C. Insulation resistance was measured at 25 ° C. and 85 ° C. by applying a DC voltage of 25V for 2 minutes and measured with an insulation resistance meter, and then the logarithm (volume ρ) of volume resistivity was calculated. The dielectric breakdown voltage is obtained by applying a voltage at a constant boosting rate of 100 V / min between both electrodes of a capacitor with 10 multilayer capacitors immersed in insulating oil to insulate the voltage that has caused the breakdown. Measured as breakdown voltage. The bias characteristics were as follows: an alternating voltage of 1 kHz and 1 Vrms was applied to 10 multilayer ceramic capacitors, and a direct current voltage of 1 kV / mm was superimposed thereon to confirm the rate of change in capacitance.
[0030]
Tables 3 and 4 show the results of the above tests.
[0031]
As shown in Tables 3 and 4, the non-reducing dielectric ceramic composition of the present invention has a high dielectric constant of 8000 or more, a dielectric loss tangent of 0.5% or less, and a rate of change of capacitance with respect to temperature − Satisfies F characteristics defined in JIS standards in the range of 25 to 85 ° C. In addition, the grain size of the ceramic sintered body is as small as 2.5 μm or less, and the volume resistivity at 25 ° C. and 85 ° C. is as high as 12.0 Ωcm or more at log ρ. Further, it was confirmed that the dielectric breakdown voltage was relatively high at about 12 kV / mm, and that the bias characteristic was relatively small, that is, ΔC was about −50% when the DC electric field strength was 1 kV / mm.
[0032]
Next, the reason why each composition range of the present invention is limited will be described.
[0033]
In (Ba 1-lm Ca l Re m) p (Ti 1-no Zr n Mn o) O 3, 0 < to that the l ≦ 0.20, as in Sample No. 1, Ca addition amount l is 0 If it exceeds .20, sintering failure occurs, which is not preferable.
[0034]
The reason why 0 <m ≦ 0.05 is not preferable because the sintered porcelain becomes a semiconductor when the Nd addition amount m exceeds 0.05 as in sample number 2. Also, as in Sample No. 3, when the La addition amount m exceeds 0.05, the sintered porcelain is not preferable because it becomes a semiconductor. Similarly, as in Sample No. 4, when the Pr addition amount m exceeds 0.05, the sintered porcelain is not preferable because it becomes a semiconductor. When the rare earth element addition amount m is 0 as in sample number 28, the grain size increases to 5.0 μm, and the BDV value decreases to 8.3 kV / mm, which is not preferable.
[0035]
Next, 0 <n ≦ 0.20 was set when the Zr addition amount n was 0, as in sample number 20, and the dielectric constant ε was reduced to 6100, and the bias characteristic was also reduced to −72%. It is not preferable. Further, when the Zr addition amount n exceeds 0.20 as in the sample number 21, the dielectric constant ε becomes as small as 6300, which is not preferable.
[0036]
Next, 0 <o ≦ 0.03 is not preferable because the sintered porcelain is made into a semiconductor when the Mn addition amount o is 0 as in Sample No. 22. Moreover, when the Mn addition amount o exceeds 0.03 as in the sample number 23, it becomes unsatisfactory due to poor sintering.
[0037]
Next, 1.020 ≦ p ≦ 1.037 is not preferable because the sintering is poor when the molar ratio p is less than 1.020 as in sample number 24. Further, when the molar ratio p exceeds 1.037 as in the case of sample number 25, it is not preferable because of poor sintering.
[0038]
And when this non-reducible dielectric ceramic composition was 100 parts by weight, the glass was added in an amount of 0.3 to 2.5 parts by weight, as in sample number 26, the glass addition amount was 0.3% by weight. If it is less than the range, it becomes unsatisfactory due to sintering failure. Further, when the glass addition amount exceeds 2.5 parts by weight as in sample number 27, the grain size increases to 4.0 μm, and the BDV value decreases to 9.0 kV / mm, which is not preferable.
[0039]
In this example, carbonate powder or oxides such as BaCO 3 , CaCO 3 , La 2 O 3 , CeO 2 , Nd 2 O 3 , Pr 2 O 3 , TiO 2 , ZrO 2 , and MnCO 3 are used as starting materials. Although powder was used, it is not limited to these powders, and powder produced by an alkoxide method, a coprecipitation method, or a hydrothermal synthesis method may be used.
[0040]
【The invention's effect】
According to the present invention, it is possible to obtain a non-reducing dielectric ceramic composition that is not reduced even when fired in a reducing atmosphere and does not become a semiconductor. Therefore, if a multilayer capacitor is manufactured with a porcelain using this non-reducible dielectric ceramic composition, an inexpensive base metal can be used as the internal electrode material, and the cost of the multilayer ceramic capacitor can be reduced.
[0041]
In addition, the porcelain using this non-reducing dielectric ceramic composition has a large dielectric constant, although its crystal grain size can be made sufficiently smaller than when using a conventional dielectric ceramic composition. can get. Therefore, it is possible to design a small-sized and large-capacity multilayer capacitor, and to achieve an effect that the dielectric breakdown voltage is increased and the bias characteristics are improved.
Claims (4)
一般式（Ｂａ1-m Ｒｅm ）p （Ｔｉ1-n-o Ｚｒn Ｍｎo ）Ｏ3
（但し、ＲｅはＬａ、Ｃｅ、Ｐｒ、Ｎｄの中から選ばれる少なくとも１種類）で表され、
ｍ、ｎ、ｏ及びｐが、それぞれ
０＜ｍ≦０．０５
０＜ｎ≦０．２０
０＜ｏ≦０．０３
１．０２０≦ｐ≦１．０３７
を満足する非還元性誘電体磁器組成物に、
該非還元性誘電体磁器組成物を１００重量部としたとき、ＢａＯ−ＳｒＯ−ＣａＯ−Ｌｉ2 Ｏ−ＳｉＯ2 を主成分とするガラスからなる副成分が、０．３〜２．５重量部添加されていることを特徴とする非還元性誘電体磁器組成物。The main component is
Formula (Ba 1-m Re m) p (Ti 1-no Zr n Mn o) O 3
(Where Re is at least one selected from La, Ce, Pr, and Nd),
m, n, o and p are each 0 <m ≦ 0.05
0 <n ≦ 0.20
0 <o ≦ 0.03
1.020 ≦ p ≦ 1.037
To a non-reducing dielectric ceramic composition satisfying
When the non-reducing dielectric ceramic composition is 100 parts by weight, 0.3 to 2.5 parts by weight of a subcomponent made of glass containing BaO—SrO—CaO—Li 2 O—SiO 2 as a main component is added. A non-reducing dielectric ceramic composition characterized in that:
一般式（Ｂａ1-l-m Ｃａl Ｒｅm ）p （Ｔｉ1-n-o Ｚｒn Ｍｎo ）Ｏ3
（但し、ＲｅはＬａ、Ｃｅ、Ｐｒ、Ｎｄの中から選ばれる少なくとも１種類）で表され、
ｌ、ｍ、ｎ、ｏ及びｐが、それぞれ
０＜ｌ≦０．２０
０＜ｍ≦０．０５
０＜ｎ≦０．２０
０＜ｏ≦０．０３
１．０２０≦ｐ≦１．０３７
を満足する非還元性誘電体磁器組成物に、
該非還元性誘電体磁器組成物を１００重量部としたとき、ＢａＯ−ＳｒＯ−ＣａＯ−Ｌｉ2 Ｏ−ＳｉＯ2 を主成分とするガラスからなる副成分が、０．３〜２．５重量部添加されていることを特徴とする非還元性誘電体磁器組成物。The main component is
Formula (Ba 1-lm Ca l Re m) p (Ti 1-no Zr n Mn o) O 3
(Where Re is at least one selected from La, Ce, Pr, and Nd),
l, m, n, o and p are each 0 <l ≦ 0.20
0 <m ≦ 0.05
0 <n ≦ 0.20
0 <o ≦ 0.03
1.020 ≦ p ≦ 1.037
To a non-reducing dielectric ceramic composition satisfying
When the non-reducing dielectric ceramic composition is 100 parts by weight, 0.3 to 2.5 parts by weight of a subcomponent made of glass containing BaO—SrO—CaO—Li 2 O—SiO 2 as a main component is added. A non-reducing dielectric ceramic composition characterized in that:
前記誘電体セラミック層は、主成分が、
一般式（Ｂａ1-m Ｒｅm ）p （Ｔｉ1-n-o Ｚｒn Ｍｎo ）Ｏ3
（但し、ＲｅはＬａ、Ｃｅ、Ｐｒ、Ｎｄの中から選ばれる少なくとも１種類）で表され、
ｍ、ｎ、ｏ及びｐが、それぞれ
０＜ｍ≦０．０５
０＜ｎ≦０．２０
０＜ｏ≦０．０３
１．０２０≦ｐ≦１．０３７
を満足する非還元性誘電体磁器組成物に、
該非還元性誘電体磁器組成物を１００重量部としたとき、ＢａＯ−ＳｒＯ−ＣａＯ−Ｌｉ2 Ｏ−ＳｉＯ2 を主成分とするガラスからなる副成分が、０．３〜２．５重量部添加されている非還元性誘電体磁器組成物からなり、前記内部電極はニッケルを主成分として構成されていることを特徴とする積層セラミックコンデンサ。In a multilayer ceramic capacitor comprising a plurality of dielectric ceramic layers, a plurality of internal electrodes arranged via the dielectric ceramic layers, and external electrodes connected to the internal electrodes,
The dielectric ceramic layer is composed mainly of
Formula (Ba 1-m Re m) p (Ti 1-no Zr n Mn o) O 3
(Where Re is at least one selected from La, Ce, Pr, and Nd),
m, n, o and p are each 0 <m ≦ 0.05
0 <n ≦ 0.20
0 <o ≦ 0.03
1.020 ≦ p ≦ 1.037
To a non-reducing dielectric ceramic composition satisfying
When the non-reducing dielectric ceramic composition is 100 parts by weight, 0.3 to 2.5 parts by weight of a subcomponent made of glass containing BaO—SrO—CaO—Li 2 O—SiO 2 as a main component is added. A multilayer ceramic capacitor comprising: a non-reducible dielectric ceramic composition, wherein the internal electrode is composed mainly of nickel.
前記誘電体セラミック層は、主成分が、
一般式（Ｂａ1-l-m Ｃａl Ｒｅm ）p （Ｔｉ1-n-o Ｚｒn Ｍｎo ）Ｏ3
（但し、ＲｅはＬａ、Ｃｅ、Ｐｒ、Ｎｄの中から選ばれる少なくとも１種類）で表され、
ｌ、ｍ、ｎ、ｏ及びｐが、それぞれ
０＜ｌ≦０．２０
０＜ｍ≦０．０５
０＜ｎ≦０．２０
０＜ｏ≦０．０３
１．０２０≦ｐ≦１．０３７
を満足する非還元性誘電体磁器組成物に、
該非還元性誘電体磁器組成物を１００重量部としたとき、ＢａＯ−ＳｒＯ−ＣａＯ−Ｌｉ2 Ｏ−ＳｉＯ2 を主成分とするガラスからなる副成分が、０．３〜２．５重量部添加されている非還元性誘電体磁器組成物からなり、前記内部電極はニッケルを主成分として構成されていることを特徴とする積層セラミックコンデンサ。In a multilayer ceramic capacitor comprising a plurality of dielectric ceramic layers, a plurality of internal electrodes arranged via the dielectric ceramic layers, and external electrodes connected to the internal electrodes,
The dielectric ceramic layer is composed mainly of
Formula (Ba 1-lm Ca l Re m) p (Ti 1-no Zr n Mn o) O 3
(Where Re is at least one selected from La, Ce, Pr, and Nd),
l, m, n, o and p are each 0 <l ≦ 0.20
0 <m ≦ 0.05
0 <n ≦ 0.20
0 <o ≦ 0.03
1.020 ≦ p ≦ 1.037
To a non-reducing dielectric ceramic composition satisfying
When the non-reducing dielectric ceramic composition is 100 parts by weight, 0.3 to 2.5 parts by weight of a subcomponent made of glass containing BaO—SrO—CaO—Li 2 O—SiO 2 as a main component is added. A multilayer ceramic capacitor comprising: a non-reducible dielectric ceramic composition, wherein the internal electrode is composed mainly of nickel.
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| JP2001307944A (en) * | 2000-04-26 | 2001-11-02 | Taiyo Yuden Co Ltd | Method for manufacturing laminated ceramic capacitor and paste for external electrode |
| JP2002141241A (en) * | 2000-11-06 | 2002-05-17 | Murata Mfg Co Ltd | Ceramic capacitor and its manufacturing method |
| JP2002226263A (en) * | 2001-01-30 | 2002-08-14 | Kyocera Corp | Dielectric ceramic and laminated ceramic capacitor |
| JP4652595B2 (en) * | 2001-03-21 | 2011-03-16 | 京セラ株式会社 | Dielectric porcelain with excellent temperature characteristics |
| KR100466073B1 (en) * | 2002-05-24 | 2005-01-13 | 삼성전기주식회사 | Dielectric Composition Having Improved Homogeneity And Insulation Resistance, Preparing Method Thereof And Multilayer Ceramic Condenser Using The Same |
| JP5132972B2 (en) * | 2007-04-09 | 2013-01-30 | 太陽誘電株式会社 | Dielectric ceramics, manufacturing method thereof, and multilayer ceramic capacitor |
| JP5067401B2 (en) | 2009-06-30 | 2012-11-07 | 株式会社村田製作所 | Dielectric ceramic, manufacturing method thereof, and multilayer ceramic capacitor |
| JP5883217B2 (en) * | 2009-11-06 | 2016-03-09 | Tdk株式会社 | Hexagonal barium titanate powder, method for producing the same, dielectric ceramic composition, and electronic component |
| CN105399420B (en) * | 2015-11-26 | 2018-03-09 | 西安工业大学 | A kind of Ti bases high-permittivity microwave medium ceramics and preparation method thereof |
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1995
- 1995-07-11 JP JP17508995A patent/JP3796771B2/en not_active Expired - Lifetime
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