JP4720193B2 - Dielectric ceramic and manufacturing method thereof, and multilayer ceramic capacitor - Google Patents

Dielectric ceramic and manufacturing method thereof, and multilayer ceramic capacitor Download PDF

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JP4720193B2
JP4720193B2 JP2005016090A JP2005016090A JP4720193B2 JP 4720193 B2 JP4720193 B2 JP 4720193B2 JP 2005016090 A JP2005016090 A JP 2005016090A JP 2005016090 A JP2005016090 A JP 2005016090A JP 4720193 B2 JP4720193 B2 JP 4720193B2
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徳之 井上
晴信 佐野
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株式会社村田製作所
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    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01GCAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G4/00Fixed capacitors; Processes of their manufacture
    • H01G4/002Details
    • H01G4/018Dielectrics
    • H01G4/06Solid dielectrics
    • H01G4/08Inorganic dielectrics
    • H01G4/12Ceramic dielectrics
    • H01G4/1209Ceramic dielectrics characterised by the ceramic dielectric material
    • H01G4/1218Ceramic dielectrics characterised by the ceramic dielectric material based on titanium oxides or titanates
    • H01G4/1227Ceramic dielectrics characterised by the ceramic dielectric material based on titanium oxides or titanates based on alkaline earth titanates
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01GCAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G4/00Fixed capacitors; Processes of their manufacture
    • H01G4/30Stacked capacitors

Description

本発明は、誘電体セラミックおよびその製造方法、ならびに積層セラミックコンデンサに関し、さらに詳しくは、電圧印加時に生じる電界誘起歪み(以下、「電歪」と示す)が小さく、その電歪により発生する鳴きが小さい誘電体セラミックおよびその製造方法に関する。   The present invention relates to a dielectric ceramic, a method of manufacturing the same, and a multilayer ceramic capacitor. More specifically, the electric field induced strain (hereinafter referred to as “electrostriction”) generated when a voltage is applied is small, and a squeal generated by the electrostriction is generated. The present invention relates to a small dielectric ceramic and a manufacturing method thereof.
積層セラミックコンデンサに好適なABO3ペロブスカイト系誘電体セラミックにおいて、その誘電体セラミックを構成する主相粒子が、通称「コアシェル構造」を有するものが知られている。この「コアシェル」とは、希土類等の添加成分の濃度が高い「シェル」、および希土類等の添加成分の濃度が低い「コア」の二種類の領域からなることをいい、「シェル」領域は、「コア」領域と比較して、添加成分の濃度が高い分、キュリー温度が低い、すなわち強誘電性が低い。この「コアシェル構造」は、たとえば、チタン酸バリウム等の主成分に希土類元素などを含む添加成分を添加し、適切な条件にて焼成することによって得られる。 Among ABO 3 perovskite dielectric ceramics suitable for multilayer ceramic capacitors, it is known that the main phase particles constituting the dielectric ceramic have a so-called “core-shell structure”. This "core shell" means that it consists of two regions of "shell" where the concentration of the additive component such as rare earth is high and "core" where the concentration of the additive component such as rare earth is low, and the "shell" region is Compared with the “core” region, the higher the concentration of the additive component, the lower the Curie temperature, that is, the lower the ferroelectricity. This “core-shell structure” can be obtained, for example, by adding an additive component containing a rare earth element or the like to a main component such as barium titanate and firing under appropriate conditions.
上記のような「コアシェル構造」を有する誘電体セラミックの製造方法が、特許文献1に開示されている。すなわち、出発原料として、ABO3系化合物(Aは、Ba、BaおよびCa、またはBa、CaおよびSrであり、Bは、Ti、またはTiおよびZrである。)からなり、かつ平均粉末径が0.1〜0.3μmである主成分粉末を用意するとともに、原子番号57〜71の希土類元素の少なくとも1種を含む希土類元素化合物、Mg化合物、Mn化合物、BaZrO3 およびSi化合物の各々からなる副成分粉末とを用意する工程と、前記主成分粉末および前記副成分粉末を混合して混合粉末を得る工程と、前記混合粉末を成形して成形体を得る工程と、前記成形体を還元性雰囲気中で焼成する工程とを備え、前記焼成工程によって得られた非還元性誘電体セラミックに含まれるセラミック結晶は、コアシェル構造を有し、かつコア径<0.4×グレイン径の条件を満たすとともに、その平均グレイン径が、0.15〜0.8μmであり、かつ前記主成分粉末の平均粉末径の1.5倍以上とされる、非還元性誘電体セラミックの製造方法である。 A method for manufacturing a dielectric ceramic having the “core-shell structure” as described above is disclosed in Patent Document 1. That is, the starting material is an ABO 3 compound (A is Ba, Ba and Ca, or Ba, Ca and Sr, and B is Ti, or Ti and Zr), and the average powder diameter is A main component powder having a thickness of 0.1 to 0.3 μm is prepared, and each of the rare earth element compound containing at least one rare earth element having an atomic number of 57 to 71, an Mg compound, an Mn compound, a BaZrO 3, and an Si compound. Preparing a sub-component powder, mixing the main component powder and the sub-component powder to obtain a mixed powder, forming the mixed powder to obtain a compact, and reducing the compact A ceramic crystal contained in the non-reducing dielectric ceramic obtained by the firing step has a core-shell structure and a core diameter <0.4. A non-reducing dielectric ceramic that satisfies the grain diameter condition, has an average grain diameter of 0.15 to 0.8 μm, and is not less than 1.5 times the average powder diameter of the main component powder. It is a manufacturing method.
この特許文献1に開示された非還元性誘電体セラミックの製造方法によれば、誘電率の温度特性が平坦で、高電界下での信頼性が高い誘電体セラミックを得ることができ、これにより、小型かつ大容量でありながら、電歪に起因する鳴きが小さい積層セラミックコンデンサを実現できることができる。
特開2004−345927号公報
According to the method of manufacturing a non-reducing dielectric ceramic disclosed in Patent Document 1, a dielectric ceramic having a flat temperature characteristic of dielectric constant and high reliability under a high electric field can be obtained. Therefore, it is possible to realize a monolithic ceramic capacitor that is small and has a large capacity, and that has a small noise due to electrostriction.
JP 2004-345927 A
しかしながら、特許文献1における誘電体セラミックでは、30kV/mmの電界を印加したときの電歪が0.074〜0.082%とまだ不十分であるという問題があった。仮に積層セラミックコンデンサの電歪が大きいと、大きい鳴きを引き起こすという不具合が生じる。   However, the dielectric ceramic disclosed in Patent Document 1 has a problem that the electrostriction when an electric field of 30 kV / mm is applied is still inadequate, 0.074 to 0.082%. If the electrostriction of the multilayer ceramic capacitor is large, there is a problem that it causes a large squeal.
そこで、本発明の目的は、電界印加時に生じる電歪が小さく、望ましくは誘電率εが大きく、誘電率の温度特性が平坦である誘電体セラミックを提供することである。   Accordingly, an object of the present invention is to provide a dielectric ceramic that has a small electrostriction generated when an electric field is applied, preferably has a large dielectric constant ε, and has a flat temperature characteristic of the dielectric constant.
また、本発明の他の目的は、上記の要求特性を満足する誘電体セラミックの製造方法を提供することである。   Another object of the present invention is to provide a method for producing a dielectric ceramic that satisfies the above required characteristics.
さらに、本発明の他の目的は、上述の誘電体セラミックを用い、小型大容量でありながら温度特性が良好で、かつ電歪に起因する鳴きが小さい積層セラミックコンデンサを提供することである。   Furthermore, another object of the present invention is to provide a multilayer ceramic capacitor using the above-mentioned dielectric ceramic, having a small size and a large capacity, good temperature characteristics, and small noise due to electrostriction.
上述した技術的課題を解決するため、本発明に係る誘電体セラミックは、次のような構成を備えることを特徴としている。   In order to solve the technical problem described above, the dielectric ceramic according to the present invention is characterized by having the following configuration.
すなわち本発明は、(Ba 1-x-y Ca x Sr y )(Ti 1-z Zr z )O 3 (ただし、0≦x+y≦0.15,0≦z≦0.3)を含み、かつ、前記(Ba 1-x-y Ca x Sr y )(Ti 1-z Zr z )O 3 100モル部に対し、希土類元素R(Y,La,Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb,Luの少なくとも1種)を4〜30モル部、BaZrO 3 を2〜30(ただし、100zとの合計値が30を超えない)モル部含む、組成を有する、誘電体セラミックにおいて、 前記誘電体セラミックの主相粒子が、前記(Ba 1-x-y Ca x Sr y )(Ti 1-z Zr z )O 3 および前記希土類元素Rを含むぺロブスカイト構造からなる固溶体であり、前記主相粒子が、2つの領域、すなわち前記希土類元素の濃度が高い第1の領域と前記希土類元素の濃度が低い第2の領域から構成され、前記第1の領域における希土類元素の平均濃度が、前記領域第2の領域における希土類元素の平均濃度に対し、モル比で3倍以上であるとともに、前記誘電体セラミックの断面を観察したとき、前記第2の領域の直径の分布におけるD90値が0.25μm未満であることを特徴とする。
That is, the present invention includes the (Ba 1-xy Ca x Sr y) (Ti 1-z Zr z) O 3 ( however, 0 ≦ x + y ≦ 0.15,0 ≦ z ≦ 0.3), and the (Ba 1-xy Ca x Sr y) (Ti 1-z Zr z) O 3 100 parts by mol relative to the rare earth element R (Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, 4 to 30 mol parts of at least one of Ho, Er, Tm, Yb, and Lu) and 2 to 30 mol parts of BaZrO 3 (however, the total value with 100z does not exceed 30). in the body the ceramic, the dielectric ceramic main phase grains, the (Ba 1-xy Ca x Sr y) (Ti 1-z Zr z) O 3 and the be the solid solution consisting of a perovskite structure containing a rare earth element R , The main phase particles are in two regions, that is, a first concentration of the rare earth element is high. And the second region having a low concentration of the rare earth element, and the average concentration of the rare earth element in the first region is three times the molar ratio of the average concentration of the rare earth element in the second region. In addition, when the cross section of the dielectric ceramic is observed, the D90 value in the diameter distribution of the second region is less than 0.25 μm.
また、前記任意の断面を観察したとき、前記第2の領域の直径の分布におけるD50値が0.05μm以上であるのが望ましい。   Further, when the arbitrary cross section is observed, it is desirable that the D50 value in the diameter distribution of the second region is 0.05 μm or more.
さらに、前記ABO3100モル部に対し、Mgを1〜20モル部、Siを1〜15モル部以上含有するのも好ましい。 Furthermore, it is also preferable to contain 1 to 20 mol parts of Mg and 1 to 15 mol parts or more of Si with respect to 100 mol parts of the ABO 3 .
本発明の誘電体セラミックは、たとえば、以下の工程を備える製造方法によって製造される。
すなわち、(Ba 1-x-y Ca x Sr y )(Ti 1-z Zr z )O 3 (ただし、0≦x+y≦0.15,0≦z≦0.3)を主成分とする第1の原料粉末、BaZrO3を主成分とする第2の原料粉末、および少なくとも希土類化合物を含む第3の原料粉末を用意する工程と、前記第1の原料粉末および第2の原料粉末を液中で混合、分散し、その後前記液中に第3の原料粉末を添加、混合し、乾燥して第4の原料粉末を得る工程と、前記第4の原料粉末を成形し、焼成する工程を備える誘電体セラミックの製造方法であって、前記第2の原料粉末の平均粒径が、前記第1の原料粉末の平均粒径の1/30〜1/3であることを特徴とする。
The dielectric ceramic of the present invention is manufactured, for example, by a manufacturing method including the following steps.
That, (Ba 1-xy Ca x Sr y) (Ti 1-z Zr z) O 3 ( however, 0 ≦ x + y ≦ 0.15,0 ≦ z ≦ 0.3) first raw material composed mainly of Preparing a powder, a second raw material powder containing BaZrO 3 as a main component, and a third raw material powder containing at least a rare earth compound, and mixing the first raw material powder and the second raw material powder in a liquid; A dielectric ceramic comprising a step of dispersing, then adding, mixing and drying a third raw material powder in the liquid to obtain a fourth raw material powder, and forming and firing the fourth raw material powder The average particle size of the second raw material powder is 1/30 to 1/3 of the average particle size of the first raw material powder.
また、この発明は、さらに積層セラミックコンデンサにも向けられる。   The present invention is also directed to a multilayer ceramic capacitor.
すなわち、積層された複数の誘電体セラミック層と、前記誘電体セラミック層間に配置された内部電極と、前記内部電極に電気的に接続された外部電極とを備え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が、本発明誘電体セラミックによって形成されてなることを特徴とする積層セラミックコンデンサである。   That is, in the multilayer ceramic capacitor comprising a plurality of laminated dielectric ceramic layers, an internal electrode disposed between the dielectric ceramic layers, and an external electrode electrically connected to the internal electrode, the dielectric ceramic The multilayer ceramic capacitor is characterized in that the layer is formed of the dielectric ceramic of the present invention.
以上のように、本発明の誘電体セラミックによれば、その主相粒子中に粗大な第2の領域が殆ど存在しないため、中高圧の電界印加時における電歪が小さくなる。また、第2の領域の平均直径が比較的大きいことにより、さらにはセラミック組成を適切な範囲に設定することにより、εが500以上と高く、誘電率温度特性が平坦になる。   As described above, according to the dielectric ceramic of the present invention, since there is almost no coarse second region in the main phase particles, electrostriction during application of a medium-high voltage electric field is reduced. In addition, since the average diameter of the second region is relatively large, and further, by setting the ceramic composition in an appropriate range, ε is as high as 500 or more, and the dielectric constant temperature characteristic becomes flat.
したがって、本発明の誘電体セラミックを用いた積層セラミックコンデンサは、小型大容量でありながら、静電容量温度特性がX7S特性を満足し、かつ電歪に起因する鳴きが小さい。   Therefore, the multilayer ceramic capacitor using the dielectric ceramic of the present invention is small in size and large capacity, has a capacitance temperature characteristic satisfying the X7S characteristic, and has a small squeal due to electrostriction.
まず、本発明の誘電体セラミックの主要な用途である、積層セラミックコンデンサについて説明する。図1は一般的な積層セラミックコンデンサ1を示す断面図である。   First, a multilayer ceramic capacitor, which is the main use of the dielectric ceramic of the present invention, will be described. FIG. 1 is a cross-sectional view showing a general multilayer ceramic capacitor 1.
積層セラミックコンデンサ1は、直方体状のセラミック積層体2を備えている。セラミック積層体2は、複数の積層された誘電体セラミック層3と、複数の誘電体セラミック層3間の特定の界面に沿って形成された複数の内部電極4および5とを備えている。内部電極4および5は、セラミック積層体2の外表面にまで到達するように形成されるが、セラミック積層体2の一方の端面6にまで引き出される内部電極4と他方の端面7にまで引き出される内部電極5とが、セラミック積層体2の内部において、誘電体セラミック層3を介して静電容量を取得できるように交互に配置されている。   The multilayer ceramic capacitor 1 includes a rectangular parallelepiped ceramic multilayer body 2. The ceramic laminate 2 includes a plurality of laminated dielectric ceramic layers 3 and a plurality of internal electrodes 4 and 5 formed along a specific interface between the plurality of dielectric ceramic layers 3. The internal electrodes 4 and 5 are formed so as to reach the outer surface of the ceramic laminate 2, but are drawn to the internal electrode 4 and the other end surface 7 that are drawn to one end face 6 of the ceramic laminate 2. The internal electrodes 5 are alternately arranged inside the ceramic laminate 2 so that electrostatic capacity can be obtained via the dielectric ceramic layer 3.
内部電極4および5の導電材料は、低コストであるニッケルもしくはニッケル合金、銅もしくは銅合金、または銀もしくは銀合金であることが好ましい。   The conductive material of the internal electrodes 4 and 5 is preferably nickel or a nickel alloy, copper or a copper alloy, or silver or a silver alloy, which is low cost.
前述した静電容量を取り出すため、セラミック積層体2の外表面上であって、端面6および7上には、内部電極4および5のいずれか特定のものに電気的に接続されるように、外部電極8および9がそれぞれ形成されている。外部電極8および9に含まれる導電材料としては、内部電極4および5の場合と同じ導電材料を用いることができ、さらに、銀、パラジウム、銀−パラジウム合金なども用いることができる。外部電極8および9は、このような金属粉末にガラスフリットを添加して得られた導電性ペーストを付与し、焼き付けることによって形成される。   In order to take out the above-described capacitance, on the outer surface of the ceramic laminate 2 and on the end faces 6 and 7, so as to be electrically connected to any one of the internal electrodes 4 and 5, External electrodes 8 and 9 are respectively formed. As the conductive material contained in the external electrodes 8 and 9, the same conductive material as in the case of the internal electrodes 4 and 5 can be used, and silver, palladium, a silver-palladium alloy, and the like can also be used. The external electrodes 8 and 9 are formed by applying and baking a conductive paste obtained by adding glass frit to such metal powder.
また、外部電極8および9上には、必要に応じて、ニッケル、銅などからなる第1のめっき層10および11がそれぞれ形成され、さらにその上には、半田、錫などからなる第2のめっき層12および13がそれぞれ形成される。   Further, first plating layers 10 and 11 made of nickel, copper or the like are formed on the external electrodes 8 and 9 as required, and a second plating layer made of solder, tin or the like is further formed thereon. Plating layers 12 and 13 are formed, respectively.
次に、本発明の誘電体セラミックの詳細について説明する。本発明の誘電体セラミックは、ABO3(AはBaを含み、BはTiを含む)で表され、かつ希土類元素Rを含むペロブスカイト構造からなる固溶体を主相粒子とし、前記主相粒子が、2つの領域、すなわち前記希土類元素の濃度が高い第1の領域と前記希土類元素の濃度が低い第2の領域から構成される誘電体セラミックであって、前記誘電体セラミックの任意の断面を観察したとき、前記第2の領域の直径の分布におけるD90値が0.25μm未満であることを特徴とする。この断面の模式図を図2に示す。 Next, details of the dielectric ceramic of the present invention will be described. The dielectric ceramic of the present invention is a solid solution composed of a perovskite structure represented by ABO 3 (A includes Ba and B includes Ti) and includes a rare earth element R, and the main phase particles include: A dielectric ceramic composed of two regions, ie, a first region having a high concentration of the rare earth element and a second region having a low concentration of the rare earth element, and an arbitrary cross section of the dielectric ceramic was observed. The D90 value in the diameter distribution of the second region is less than 0.25 μm. A schematic view of this cross section is shown in FIG.
主相粒子11に希土類元素Rが固溶すると、希土類元素の濃度が高い第1領域12と、希土類元素の濃度が低い第2の領域13に分かれる。このとき、たとえばABO3がBaTiO3系の場合、第1の領域は第2の領域より希土類の固溶が進んでいるため、キュリー温度が低下し、強誘電性が低くなっている。 When the rare earth element R is dissolved in the main phase particle 11, it is divided into a first region 12 where the concentration of the rare earth element is high and a second region 13 where the concentration of the rare earth element is low. At this time, for example, when ABO 3 is a BaTiO 3 system, since the first region is more solid-dissolved in the rare earth than the second region, the Curie temperature is lowered and the ferroelectricity is lowered.
上述のように強誘電性が低くなると、電歪が小さくなる。これは、ここでいう電歪すなわち電界誘起歪みには、電界の2乗に比例する本来の「電歪」に加え、電界の1乗に比例する強誘電性に起因する歪みも含まれているためである。すなわち、電歪を低減するには第2の領域13の面積(実際は体積)を小さくすればよい。   As described above, when the ferroelectricity is lowered, the electrostriction is reduced. This is because the electrostriction, that is, the electric field induced strain here includes not only the original “electrostriction” proportional to the square of the electric field but also distortion caused by the ferroelectricity proportional to the first power of the electric field. Because. That is, in order to reduce electrostriction, the area (actually volume) of the second region 13 may be reduced.
ただし、電歪低減に最も重要な要素は、第2の領域13の直径の平均値が小さいことではなく、たとえ少数でも粗大な第2の領域13があってはならないということである。すなわち、多数個の第2の領域13の直径の累積分布曲線をとった場合、そのD50値ではなく、D90値が小さいことが求められる。具体的には、本発明の誘電体セラミックでは、主相粒子11の直径に関わらず、第2の領域13の直径におけるD90値が0.25μm未満である。仮に、図3の模式的な断面図に示すように、D50値が小さくてもD90値が大きければ、電歪が0.055%以上と大きくなり、鳴きの不具合が増大するわけである。したがって、本発明は、主相粒子に対する第2の領域の面積比の平均値に着目した従来技術とは本質的に異なる。   However, the most important factor for electrostriction reduction is not that the average value of the diameter of the second region 13 is small, but that there should be no coarse second region 13 even if it is a small number. That is, when taking a cumulative distribution curve of the diameters of a large number of second regions 13, it is required that the D90 value is small, not the D50 value. Specifically, in the dielectric ceramic of the present invention, the D90 value in the diameter of the second region 13 is less than 0.25 μm regardless of the diameter of the main phase particles 11. As shown in the schematic cross-sectional view of FIG. 3, even if the D50 value is small, if the D90 value is large, the electrostriction increases to 0.055% or more, and the problem of squeal increases. Therefore, the present invention is essentially different from the prior art that focuses on the average value of the area ratio of the second region to the main phase particles.
仮に、第2の領域の合計体積がほぼ同じである2つのケース、すなわち、大きな第2の領域が少数あるケースと、小さな第2の領域が多数存在するケースを想定する。この場合、後者のケースのほうが、強誘電体のサイズ効果によって強誘電性が弱められ、電歪が小さくなる。さらに、後者のケースの方が、前者のケースと比較して、電歪の小さい第1の領域との境界となる表面積が多いため、第2の領域における強誘電性の分域反転による歪みが拘束され、電歪がさらに小さくなると考えられる。このため、誘電体セラミック全体にて第1の領域と第2の領域の体積比を固定した場合でも、本発明のような多数の小さな第2の領域を有する誘電体セラミックのほうが電歪低減に効果的なわけである。   Suppose two cases where the total volume of the second region is substantially the same, that is, a case where there are a small number of large second regions and a case where there are a large number of small second regions. In this case, in the latter case, the ferroelectricity is weakened by the size effect of the ferroelectric material, and the electrostriction is reduced. Furthermore, since the latter case has a larger surface area as a boundary with the first region having a smaller electrostriction than the former case, the distortion due to the ferroelectric domain inversion in the second region is less. It is constrained and the electrostriction is considered to be further reduced. For this reason, even when the volume ratio between the first region and the second region is fixed in the entire dielectric ceramic, the dielectric ceramic having a large number of small second regions as in the present invention can reduce electrostriction. It is effective.
したがって、主相粒子11内の第1の領域12と第2の領域13は、それぞれ複数の領域からなっていても構わない。   Therefore, the first region 12 and the second region 13 in the main phase particle 11 may each be composed of a plurality of regions.
また、本発明の誘電体セラミックにおいて、第1の領域12における希土類元素の平均濃度は、第2の領域13における希土類元素の平均濃度に対し、モル比で3倍以上であることが好ましい。3倍未満となると、第1の領域12と第2の領域13との間の特性の差異が小さくなり、所望の誘電率、温度特性を満足する誘電体セラミックを得ることができない。   In the dielectric ceramic of the present invention, the average concentration of the rare earth element in the first region 12 is preferably 3 times or more in terms of molar ratio with respect to the average concentration of the rare earth element in the second region 13. If it is less than 3 times, the difference in characteristics between the first region 12 and the second region 13 becomes small, and a dielectric ceramic satisfying desired dielectric constant and temperature characteristics cannot be obtained.
さらに、第2の領域13の直径の分布におけるD50値は、0.05μm以上であることが望ましい。0.05μm未満であると、誘電体セラミック全体として強誘電性が低くなるため、誘電率が500未満と低くなる。また静電容量の温度特性もX7S特性を満足できない。   Further, the D50 value in the diameter distribution of the second region 13 is preferably 0.05 μm or more. If it is less than 0.05 μm, the ferroelectricity of the dielectric ceramic as a whole will be low, and the dielectric constant will be low, below 500. Also, the temperature characteristic of the capacitance cannot satisfy the X7S characteristic.
ここで、本発明の誘電体セラミックの具体的な組成の一実施形態について説明する。すなわち、ABO3が(Ba1-x-yCaxSry)(Ti1-zZrz)O3(ただし、0≦x+y≦0.15,0≦z≦0.3)であり、前記ABO3100モル部に対し、希土類元素R(Y,La,Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb,Luの少なくとも1種)を4〜30モル部、BaZrO3を2〜30(ただし、100zとの合計値が30を超えない)モル部含有する誘電体セラミックである。 Here, an embodiment of a specific composition of the dielectric ceramic of the present invention will be described. That is, ABO 3 is (Ba 1-xy Ca x Sr y) (Ti 1-z Zr z) O 3 ( however, 0 ≦ x + y ≦ 0.15,0 ≦ z ≦ 0.3), the ABO 3 4 to 30 mol parts of rare earth element R (at least one of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) with respect to 100 mol parts , BaZrO 3 is a dielectric ceramic containing 2 to 30 mole parts (however, the total value with 100z does not exceed 30).
主相粒子11の主成分はBaTiO3系が好ましく、BaはSrまたはCaで、TiはZrで所定量置換されていても構わない。希土類元素Rは、特性調整以外にも、主相粒子11に固溶して、第1の領域12と第2の領域13を構成する作用がある。Zrも誘電率や温度特性に影響を与える因子であるが、別途BaZrO3として適量添加されるのが好ましい。 The main component of the main phase particles 11 is preferably a BaTiO 3 system, where Ba may be replaced with Sr or Ca, and Ti may be substituted with a predetermined amount of Zr. In addition to adjusting the characteristics, the rare earth element R has an effect of forming a first region 12 and a second region 13 by dissolving in the main phase particle 11. Zr is also a factor affecting the dielectric constant and temperature characteristics, but it is preferable to add an appropriate amount separately as BaZrO 3 .
さらには、前記ABO3100モル部に対し、Mgを1〜20モル部、Siを1〜15モル部以上含有するのも好ましい。 Furthermore, it is preferable to contain 1 to 20 mol parts of Mg and 1 to 15 mol parts or more of Si with respect to 100 mol parts of the ABO 3 .
上記組成を満たす場合、誘電率が500以上と高く、また温度特性が良好な、すなわち25℃における静電容量を基準とした−55℃〜125℃における変化率が±22%以下であるX7S特性を満たす誘電体セラミックが得られる。上記の組成範囲においては、上記温度範囲内で誘電率の変化率が最大となる温度は125℃であるため、125℃における変化率を温度特性の指標とする。   When the above composition is satisfied, the dielectric constant is as high as 500 or more, and the temperature characteristic is good, that is, the change rate from −55 ° C. to 125 ° C. based on the capacitance at 25 ° C. is ± 22% or less. A dielectric ceramic satisfying the above is obtained. In the above composition range, the temperature at which the change rate of the dielectric constant becomes maximum within the above temperature range is 125 ° C., and thus the change rate at 125 ° C. is used as an index of temperature characteristics.
なお、元素としてのZrは、その一部をHfで置換されていても構わない。HfはZrと殆ど同じ作用をなすものであり、一部が置換されても本発明の目的に影響を及ぼすことはない。   Note that Zr as an element may be partially substituted with Hf. Hf has almost the same action as Zr, and even if a part thereof is substituted, the object of the present invention is not affected.
Sr置換量が0.15を超えると、誘電率が500未満となり好ましくない。また、Ca置換量が0.15を超えると、温度特性が悪くなり、好ましくない。また、Sr置換とCa置換を同時に行った場合は、その置換量の合計が0.15を超えた場合、誘電率が低くなり、また温度特性が悪くなり、好ましくない。   When the Sr substitution amount exceeds 0.15, the dielectric constant becomes less than 500, which is not preferable. On the other hand, when the Ca substitution amount exceeds 0.15, the temperature characteristics deteriorate, which is not preferable. Further, when the Sr substitution and the Ca substitution are performed at the same time, if the total substitution amount exceeds 0.15, the dielectric constant is lowered and the temperature characteristics are deteriorated, which is not preferable.
希土類元素Rの(Ba1-x-yCaxSry)(Ti1-zZrz)O3100モル部に対する含有量が4モル部未満となると、温度特性が悪くなり、好ましくない。30モル部を超えると、誘電率が低くなり、好ましくない。 When the content of the rare earth element R with respect to 100 parts by mole of (Ba 1-xy Ca x Sr y ) (Ti 1 -z Zr z ) O 3 is less than 4 parts by mole, the temperature characteristics are deteriorated, which is not preferable. When it exceeds 30 mol parts, the dielectric constant becomes low, which is not preferable.
BaZrO3は(Ba1-x-yCaxSry)(Ti1-zZrz)O3100モル部に対して、2モル部以上30モル部以下含有されるのが好ましい。ただし、Zrの置換量100zとの合計で30モル部を超えると、誘電率が低くなり、温度特性が悪くなる。また2モル部未満の場合、温度特性が悪くなるため、好ましくない。 BaZrO 3 is preferably contained in an amount of 2 mol parts or more and 30 mol parts or less with respect to 100 mol parts of (Ba 1-xy Ca x S r y ) (Ti 1-z Zr z ) O 3 . However, when it exceeds 30 mol parts in total with the substitution amount of Zr 100z, the dielectric constant is lowered and the temperature characteristics are deteriorated. On the other hand, when the amount is less than 2 mole parts, the temperature characteristics deteriorate, which is not preferable.
Mgの(Ba1-x-yCaxSry)(Ti1-zZrz)O3100モル部に対する含有量が1モル部未満となると、温度特性が悪くなり、好ましくない。また20モル部を超えると、誘電率が低くなり、かつ温度特性が悪くなり、好ましくない。 If the content for the (Ba 1-xy Ca x Sr y) (Ti 1-z Zr z) O 3 100 molar parts of Mg is less than 1 part by mol, the temperature characteristic is deteriorated, which is undesirable. On the other hand, when it exceeds 20 parts by mole, the dielectric constant is lowered and the temperature characteristics are deteriorated, which is not preferable.
Siは(Ba1-x-yCaxSry)(Ti1-zZrz)O3100モル部に対して1モル部以上含有されることによって、誘電体セラミックの焼結性が向上する。ただし、15モル部を超えて含有されると、誘電率が低くなる。 By containing 1 mol part or more of Si with respect to 100 mol parts of (Ba 1-xy Ca x S r y ) (Ti 1-z Zr z ) O 3 , the sinterability of the dielectric ceramic is improved. However, if the content exceeds 15 mol parts, the dielectric constant is lowered.
次いで、本発明の誘電体セラミックの製造方法の一実施形態について説明する。すなわち本発明の誘電体セラミックの製造方法は、ABO3(AはBaを含み、BはTiを含む)を主成分とする第1の原料粉末、BaZrO3を主成分とする第2の原料粉末、および少なくとも希土類化合物を含む第3の原料粉末を用意する工程と、前記第1の原料粉末および前記第2の原料粉末を液中で混合、分散し、その後前記液中に前記第3の原料粉末を添加、混合し、乾燥して第4の原料粉末を得る工程と、前記第4の原料粉末を成形し、焼成する工程を備える誘電体セラミックの製造方法であって、前記第2の原料粉末の平均粒径が、前記第1の原料粉末の平均粒径の1/30〜1/3であることを特徴とする。 Next, an embodiment of a method for producing a dielectric ceramic according to the present invention will be described. That is, the dielectric ceramic manufacturing method of the present invention includes a first raw material powder mainly containing ABO 3 (A containing Ba and B containing Ti), and a second raw material powder mainly containing BaZrO 3. And a step of preparing a third raw material powder containing at least a rare earth compound, and mixing and dispersing the first raw material powder and the second raw material powder in a liquid, and then the third raw material in the liquid A method for producing a dielectric ceramic, comprising: adding a powder, mixing and drying to obtain a fourth raw material powder; and forming and firing the fourth raw material powder, wherein the second raw material The average particle size of the powder is 1/30 to 1/3 of the average particle size of the first raw material powder.
これにより、第4の原料粉末は、第1の原料粉末の周囲に、微粒の第2の原料粉末が十分に分散している状態となる。例として、BaTiO3粉末粒子31に、微粒のBaZrO3粉末粒子32が分散している状態の模式図を図4に示す。なお、図4では第3の原料粉末の記載は省略してある。第3の原料粉末も十分に分散しているほうが好ましいが、その求められる分散度の水準は第2の原料粉末の水準ほど高くはない。 As a result, the fourth raw material powder is in a state where the fine second raw material powder is sufficiently dispersed around the first raw material powder. As an example, FIG. 4 shows a schematic diagram of a state in which fine BaZrO 3 powder particles 32 are dispersed in BaTiO 3 powder particles 31. In FIG. 4, the description of the third raw material powder is omitted. Although it is preferable that the third raw material powder is sufficiently dispersed, the level of dispersion required is not as high as that of the second raw material powder.
このようにして微粒のBaZrO3粉末粒子32が十分に分散した第4の原料粉末を、成形し、焼成すると、焼結した誘電体セラミックの第2の領域13の直径の分布がシャープになり、粗大な第2の領域の生成を防止できる。したがって、あとは焼成温度を制御するなどの方法で、第2の領域13の直径の分布におけるD50値やD90値を所望の値に制御しやすくなる。また、焼成温度を高くすると希土類元素Rの主相粒子11への固溶が促進され、第2の領域が小さくなる傾向にある。 When the fourth raw material powder in which the fine BaZrO 3 powder particles 32 are sufficiently dispersed in this way is molded and fired, the diameter distribution of the second region 13 of the sintered dielectric ceramic becomes sharp, Generation of a coarse second region can be prevented. Therefore, the D50 value and D90 value in the diameter distribution of the second region 13 can be easily controlled to a desired value by a method such as controlling the firing temperature. Further, when the firing temperature is increased, solid solution of the rare earth element R in the main phase particles 11 is promoted, and the second region tends to be reduced.
ここで、BaTiO3粉末粒子31に微粒のBaZrO3粉末粒子32が十分に分散した状態が求められる理由について説明する。図4のような状態となると、焼結時に隣り合う複数のBaTiO3粉末粒子31が互いに直接接触しにくい。そのため、BaTiO3粉末粒子31同士のネッキング現象が起こる前に、BaZrO3粉末粒子32のBaTiO3粉末粒子31への固溶が始まり、この固溶が希土類元素Rの固溶をも促進し、第1の領域12の形成が早期に進行する。このような状態になると、焼結途中で隣り合うBaTiO3粉末粒子31、すなわち焼結後の主相粒子11におけるそれぞれの第2の領域13同士が接触する可能性は低くなり、この接触に起因する粗大な第2の領域13の生成が抑制される。 Here, the reason why the fine BaZrO 3 powder particles 32 are sufficiently dispersed in the BaTiO 3 powder particles 31 will be described. When the state shown in FIG. 4, a plurality of BaTiO 3 powder particles 31 adjacent during sintering directly contact hard with each other. Therefore, before the necking phenomenon between the BaTiO 3 powder particles 31 occurs, the solid solution of the BaZrO 3 powder particles 32 into the BaTiO 3 powder particles 31 starts. This solid solution also promotes the solid solution of the rare earth element R, The formation of one region 12 proceeds early. In such a state, the BaTiO 3 powder particles 31 that are adjacent during the sintering, that is, the possibility that the respective second regions 13 in the sintered main phase particles 11 are in contact with each other is reduced, and this contact is caused. The generation of the coarse second region 13 is suppressed.
仮に、第2の原料粉末すなわちBaZrO3の平均粒径が、第1の原料粉末の平均粒径の1/3より大きい場合、図4におけるBaZrO3粉末粒子32がBaTiO3粉末粒子31間に分散しにくく、その結果、焼結後の第2の領域13の直径の分布におけるD90値が0.25μm以上と大きくなり、誘電体セラミックの電歪を低減することができない。また1/30未満の場合は、BaZrO3粉末粒子32が十分に分散しても、その粒径が小さいため、BaTiO3粉末粒子31同士の距離が短くなり、さらに第1の領域12の形成が不十分な領域が存在するため、第2の領域13同士の接触を抑制することができず、粗大な第2の領域13の生成を抑制することができない。よって、1/3より大きい場合と同様にD90値が0.25μm以上と大きくなる。 If the average particle size of the second raw material powder, that is, BaZrO 3 is larger than 1/3 of the average particle size of the first raw material powder, the BaZrO 3 powder particles 32 in FIG. 4 are dispersed between the BaTiO 3 powder particles 31. As a result, the D90 value in the diameter distribution of the second region 13 after sintering becomes as large as 0.25 μm or more, and the electrostriction of the dielectric ceramic cannot be reduced. In the case of less than 1/30, even if the BaZrO 3 powder particles 32 are sufficiently dispersed, the particle size is small, so the distance between the BaTiO 3 powder particles 31 is shortened, and the formation of the first region 12 is further reduced. Since there is an insufficient region, contact between the second regions 13 cannot be suppressed, and generation of the coarse second region 13 cannot be suppressed. Therefore, the D90 value becomes as large as 0.25 μm or more as in the case where it is larger than 1/3.
また、上記製造方法では、まず第1の原料粉末および第2の原料粉末のみを液中で混合、分散し、その後前記液中に第3の原料粉末を添加することも特徴である。仮にこれを行わず、第1の原料粉末、第2の原料粉末および第3の原料粉末を一度に液中で混合した場合、図4におけるBaZrO3粉末粒子32が十分に分散することができず、誘電体セラミックの電歪を低減することができない。 In addition, the above production method is characterized in that only the first raw material powder and the second raw material powder are first mixed and dispersed in the liquid, and then the third raw material powder is added to the liquid. If this is not performed and the first raw material powder, the second raw material powder, and the third raw material powder are mixed in the liquid at once, the BaZrO 3 powder particles 32 in FIG. 4 cannot be sufficiently dispersed. The electrostriction of the dielectric ceramic cannot be reduced.
さらに、第2の原料粉末であるBaZrO3は、特に第1の原料粉末へ固溶しやすい化合物である。仮に、BaZrO3の代わりに例えばSrZrO3用いた場合、上記の製法を行っても、希土類元素Rの第1の原料粉末への固溶が進みにくく、これも誘電体セラミックの電歪を低減することができない。 Furthermore, BaZrO 3 as the second raw material powder is a compound that is particularly easily dissolved in the first raw material powder. If, for example, SrZrO 3 is used instead of BaZrO 3 , the solid solution of the rare earth element R in the first raw material powder hardly progresses even if the above manufacturing method is performed, which also reduces the electrostriction of the dielectric ceramic. I can't.
なお、第1の原料粉末および第2の原料粉末において、その合成方法は問題とならない。例えば、固相法でも、蓚酸法、水熱法、共沈法などの湿式法でも構わない。   Note that the synthesis method of the first raw material powder and the second raw material powder is not a problem. For example, a solid phase method or a wet method such as an oxalic acid method, a hydrothermal method, or a coprecipitation method may be used.
また、第2の原料粉末として用いるBaZrO3は、前述と同様に、そのZrが一部Hfで置換されていても構わない。 Further, BaZrO 3 used as the second raw material powder may be partially substituted with Hf, as described above.
さらに、本発明の誘電体セラミックには、本発明の目的を損なわない範囲で、アルカリ金属、Cl、S、P等の不可避的な不純物が含まれていても構わない。   Furthermore, the dielectric ceramic of the present invention may contain inevitable impurities such as alkali metals, Cl, S, and P, as long as the object of the present invention is not impaired.
次に、本発明の誘電体セラミックの微構造の分析方法および電気特性の測定について説明する。   Next, the analysis method of the microstructure of the dielectric ceramic of the present invention and the measurement of electric characteristics will be described.
本発明の誘電体セラミックをカットして、厚さ約0.1μmの薄片を作製し、これを断面観察の試料とする。この試料を透過型電子顕微鏡(TEM)にて、セラミック断面を観察し、その主相粒子11の平均粒径を測定する。   The dielectric ceramic of the present invention is cut to produce a thin piece having a thickness of about 0.1 μm, which is used as a sample for cross-sectional observation. This sample is observed with a transmission electron microscope (TEM), and the cross section of the ceramic is observed, and the average particle diameter of the main phase particles 11 is measured.
第1の領域12および第2の領域13の直径については、Scanning−TEMを搭載した分解能が3nm以下のエネルギー分散型X線マイクロアナライザ(STEM−EDX)を用いることにより測定する。まず、50個の主相粒子11を無作為に抽出し、希土類元素Rの濃度をマッピング分析する。マッピングにおける希土類元素Rの濃度差により、第1の領域12および第2の領域13を特定する。その境界線を明確化するために、第1の領域12の略中央部の任意の5点において希土類元素Rの濃度の平均値を測定し、マッピング視野においてその平均値の1/3になる線を境界線とする。すなわち前記平均値の1/3未満になる領域は第2の領域13ということである。   The diameters of the first region 12 and the second region 13 are measured by using an energy dispersive X-ray microanalyzer (STEM-EDX) having a resolution of 3 nm or less equipped with Scanning-TEM. First, 50 main phase particles 11 are randomly extracted, and the concentration of the rare earth element R is analyzed by mapping. The first region 12 and the second region 13 are specified by the concentration difference of the rare earth element R in the mapping. In order to clarify the boundary line, the average value of the concentration of the rare earth element R is measured at any five points in the approximate center of the first region 12, and a line that is 1/3 of the average value in the mapping field of view. Is the boundary. That is, the region that is less than 1/3 of the average value is the second region 13.
電歪は、片側30kV/mm、1kHzの正弦波型交流電界を印加したときの変位量を測定し、その変位を電界が作用する有効厚みで除することによって求める。   Electrostriction is obtained by measuring the amount of displacement when a sinusoidal AC electric field of 1 kHz / mm and 1 kHz is applied, and dividing the displacement by the effective thickness on which the electric field acts.
次に、この発明を、実施例に基づいてより具体的に説明する。この実施例は、この発明の範囲の限定の根拠を与えるため、およびこれらによる効果を確認するために実施されたものである。   Next, the present invention will be described more specifically based on examples. This example was carried out in order to provide a basis for limiting the scope of the present invention and to confirm the effect of these.
[実施例1] 本実施例は、ある特定の組成を示すセラミックにおいて、第2の領域の大きさを変化させた積層セラミックコンデンサを作製し、それによる電歪の変化を評価したものである。   Example 1 In this example, a multilayer ceramic capacitor in which the size of the second region was changed in a ceramic having a specific composition was produced, and the change in electrostriction due thereto was evaluated.
まず、固相法により合成されたBaTiO3粉末を用意した。このBaTiO3粉末の平均一次粒径が0.20μmであり、c/a軸比は1.010であった。また、同様に固相法により合成された、様々な平均一次粒径を示すBaZrO3粉末を用意した。このときのBaZrO3粉末のBaTiO3粉末に対する一次粒径比は、表1の試料番号1〜12とおりである。さらに、Gd23、MgO、MnO2、SiO2およびBaCO3粉末を用意した。 First, BaTiO 3 powder synthesized by a solid phase method was prepared. The average primary particle size of the BaTiO 3 powder was 0.20 μm, and the c / a axial ratio was 1.010. Similarly, BaZrO 3 powders having various average primary particle sizes synthesized by a solid phase method were prepared. The primary particle size ratio of the BaZrO 3 powder to the BaTiO 3 powder at this time is as shown in Sample Nos. 1 to 12 in Table 1. Further, Gd 2 O 3 , MgO, MnO 2 , SiO 2 and BaCO 3 powder were prepared.
上記のBaTiO3粉末とBaZrO3粉末を、直径1mmφの部分安定化ジルコニア製のメディアを用いて、水中にて24時間混合し、BaTiO3粉末にBaZrO3粉末を十分に分散させたスラリーを得た。BaTiO3100モル部に対するBaZrO3量は10モル部であった。 The BaTiO 3 powder and BaZrO 3 powder were mixed in water for 24 hours using a partially stabilized zirconia media having a diameter of 1 mmφ to obtain a slurry in which the BaZrO 3 powder was sufficiently dispersed in the BaTiO 3 powder. . The amount of BaZrO 3 with respect to 100 mol parts of BaTiO 3 was 10 mol parts.
次に、上記スラリー中に、Gd23、MgO、MnO2、SiO2およびBaCO3粉末を、BaTiO3100モル部に対して、それぞれ4モル部、4モル部、0.3モル部、8モル部および1モル部添加し、さらに4時間混合した。 Next, Gd 2 O 3 , MgO, MnO 2 , SiO 2 and BaCO 3 powder in the slurry are respectively 4 mol parts, 4 mol parts, 0.3 mol parts with respect to 100 mol parts of BaTiO 3 , 8 mol part and 1 mol part were added and further mixed for 4 hours.
得られたスラリーを乾燥し、誘電体セラミックの原料粉末を得た。   The obtained slurry was dried to obtain a dielectric ceramic raw material powder.
この誘電体セラミックの原料粉末に、ポリビニルブチラール系バインダーおよびエタノールを加えて、ボールミルにより混合し、セラミックスラリーを得た。こ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成形し、セラミックグリーンシートを得た。   A polyvinyl butyral binder and ethanol were added to the dielectric ceramic raw material powder and mixed by a ball mill to obtain a ceramic slurry. This ceramic slurry was formed into a sheet by a doctor blade method to obtain a ceramic green sheet.
上記セラミックグリーンシートの表面にNiを主成分とする導電性ペーストをスクリーン印刷し、内部電極を構成するための導電ペースト層を形成した。この導電ペースト層を形成したセラミックグリーンシートを、導電性ペースト層が引き出されている側が互い違いになるように150枚積層し、積層体を得た。   A conductive paste mainly composed of Ni was screen-printed on the surface of the ceramic green sheet to form a conductive paste layer for constituting internal electrodes. 150 ceramic green sheets on which the conductive paste layer was formed were stacked so that the side from which the conductive paste layer was drawn was alternated to obtain a stacked body.
この積層体を、窒素雰囲気中にて350℃で加熱し、バインダーを燃焼させた後、H2−N2−H2Oガスからなる酸素分圧10-9.5MPaの還元性雰囲気中にて、表1の試料番号1〜12に示す温度にて60分保持し、焼成されたセラミック積層体を得た。 This laminate was heated at 350 ° C. in a nitrogen atmosphere to burn the binder, and then in a reducing atmosphere consisting of H 2 —N 2 —H 2 O gas and having an oxygen partial pressure of 10 −9.5 MPa. The ceramic laminated body which was hold | maintained for 60 minutes at the temperature shown to the sample numbers 1-12 of Table 1 and baked was obtained.
前記セラミック積層体の両端面に、ガラスフリットを含有し、Cuを主成分とする導電性ペーストを塗布し、窒素雰囲気中にて800℃にて焼付け、内部電極と電気的に接続された外部電極を形成した。さらに、はんだ付け性を良好にするため、外部電極の上にNiめっき層およびSnめっき層を形成した。   External electrodes electrically connected to the internal electrodes by applying a conductive paste containing glass frit and containing Cu as a main component to both end faces of the ceramic laminate and baking at 800 ° C. in a nitrogen atmosphere. Formed. Furthermore, in order to improve solderability, a Ni plating layer and a Sn plating layer were formed on the external electrode.
このようにして得られた試料番号1〜12の積層セラミックコンデンサの外形寸法は、長さ3.2mm、幅1.6mm、厚さ1.2mmであり、内部電極間に介在するセラミック層の厚みは3μmであり、静電容量に有効なセラミック層数は150であり、セラミック層一層当たりの対向電極面積は2.1mm2であった。 The outer dimensions of the multilayer ceramic capacitors of Sample Nos. 1 to 12 thus obtained are 3.2 mm in length, 1.6 mm in width, and 1.2 mm in thickness, and the thickness of the ceramic layer interposed between the internal electrodes. Was 3 μm, the number of ceramic layers effective for electrostatic capacity was 150, and the counter electrode area per ceramic layer was 2.1 mm 2 .
なお、試料番号13および14の試料は、その製法が試料番号1〜12の試料と異なっている。すなわち、試料番号13および14の試料はBaTiO3粉末、BaZrO3粉末、Gd23、MgO、MnO2、SiO2およびBaCO3粉末を同時に4時間混合した点が試料番号1〜12の製法と異なっており、それ以外の工程は同じである。 The samples Nos. 13 and 14 are different from the samples Nos. 1 to 12 in the manufacturing method. That is, the samples Nos. 13 and 14 are the same as the production method of Sample Nos. 1 to 12 in that BaTiO 3 powder, BaZrO 3 powder, Gd 2 O 3 , MgO, MnO 2 , SiO 2 and BaCO 3 powder were simultaneously mixed for 4 hours. They are different and the other processes are the same.
また、試料番号15および16の試料は、試料番号1〜12とは、BaZrO3粉末の代わりに平均一次粒径0.06μmのSrZrO3粉末を用いる点で異なっている。それ以外の工程は同じである。 Samples 15 and 16 differ from samples 1 to 12 in that SrZrO 3 powder having an average primary particle size of 0.06 μm is used instead of BaZrO 3 powder. The other steps are the same.
以上のようにして、試料番号1〜16の評価試料を得た。   As described above, evaluation samples of sample numbers 1 to 16 were obtained.
まず試料番号1〜16の誘電率εを、25℃にて、1kHz、1Vrmsの交流電界下における静電容量を測定することにより評価した。また温度特性の指標として、25℃における静電容量を基準とした125℃における静電容量の変化率を測定した。   First, the dielectric constants ε of sample numbers 1 to 16 were evaluated by measuring the electrostatic capacity at 25 ° C. under an alternating electric field of 1 kHz and 1 Vrms. As a temperature characteristic index, the rate of change in capacitance at 125 ° C. with respect to the capacitance at 25 ° C. was measured.
次に、試料番号1〜16の試料に、V0-P=90V、1kHzの正弦波型交流電界を印加し、試料の厚み方向への変位を測定した。この変位を静電容量に有効なセラミック層の合計厚みで除して、これを電歪とした。 Next, a sine wave type AC electric field of V 0-P = 90 V and 1 kHz was applied to the samples of sample numbers 1 to 16, and the displacement in the thickness direction of the samples was measured. This displacement was divided by the total thickness of the ceramic layer effective for capacitance, and this was electrostrictive.
次に、試料1〜16について、積層セラミックコンデンサの中央部を含む断面について、厚み約0.1μmの薄片状の分析試料を作製し、TEMを用いて50個の主相粒子の粒径を測定し、平均粒径を求めた。さらに、STEM−EDXを用いて、希土類元素のマッピング分析を行い、第1の領域および第2の領域の直径を測定した。すべての試料において、第1の領域における希土類元素の平均濃度は、第2の領域における希土類元素の平均濃度の3倍以上であった。   Next, for samples 1 to 16, a cross-section including the central portion of the multilayer ceramic capacitor was prepared as a flaky analytical sample having a thickness of about 0.1 μm, and the particle size of 50 main phase particles was measured using TEM. The average particle diameter was determined. Further, a mapping analysis of rare earth elements was performed using STEM-EDX, and the diameters of the first region and the second region were measured. In all the samples, the average concentration of the rare earth element in the first region was three times or more than the average concentration of the rare earth element in the second region.
上記の方法で測定した第1の領域および第2の領域の直径の50個における累積分布曲線を作成し、それぞれのD50値、D90値を算出した。   Cumulative distribution curves for 50 diameters of the first region and the second region measured by the above method were prepared, and the respective D50 value and D90 value were calculated.
以上の結果を表1に示す。*印を付した試料番号は、本発明の範囲外である。また、試料番号3と試料番号14の第2の領域の直径の累積分布曲線を、図5に示す。   The results are shown in Table 1. Sample numbers marked with * are outside the scope of the present invention. Moreover, the cumulative distribution curve of the diameter of the 2nd area | region of the sample number 3 and the sample number 14 is shown in FIG.
試料番号1〜6および8〜10は、第2の領域のD90値が0.25μm未満であるため、電歪が0.055%以下と小さく、鳴きが実使用上問題ないレベルとなった。   Sample Nos. 1 to 6 and 8 to 10 had a D90 value of less than 0.25 μm in the second region, so that the electrostriction was as small as 0.055% or less, and the squeal was at a level where there was no problem in practical use.
試料番号7は、BaZrO3の平均一次粒径がBaTiO3に対して1/30未満であるので、第2の領域のD90値が0.25μm以上となり、電歪が0.062%と大きい。 In Sample No. 7, since the average primary particle size of BaZrO 3 is less than 1/30 of BaTiO 3 , the D90 value in the second region is 0.25 μm or more, and the electrostriction is as large as 0.062%.
試料番号11、12はBaZrO3の平均一次粒径がBaTiO3に対して1/3より大きいため、第2の領域のD90値が0.25μm以上となり、電歪が0.058%、0.081%と大きい。 In Sample Nos. 11 and 12, since the average primary particle size of BaZrO 3 is larger than 1/3 of BaTiO 3 , the D90 value in the second region is 0.25 μm or more, electrostriction is 0.058%, and 0.5. As large as 081%.
試料番号13、14は、BaTiO3粉末、BaZrO3粉末、Gd23、MgO、MnO2、SiO2およびBaCO3粉末を同時にボールミルにて混合したため、第2の領域のD90値が0.25μm以上となり、電歪が0.075%、0.103%と大きい。 In Sample Nos. 13 and 14, BaTiO 3 powder, BaZrO 3 powder, Gd 2 O 3 , MgO, MnO 2 , SiO 2 and BaCO 3 powder were mixed at the same time by a ball mill, so the D90 value in the second region was 0.25 μm. Thus, the electrostriction is large as 0.075% and 0.13%.
試料番号15は、BaZrO3粉末の代わりにSrZrO3粉末を用いているため、十分な焼結性が得られなかった。 Sample No. 15 used SrZrO 3 powder instead of BaZrO 3 powder, so that sufficient sinterability was not obtained.
試料番号16は、試料番号15の試料の焼成温度を高くして焼結させたものであるが、D90値が0.25μm以上となり、電歪が0.079%と大きい。   Sample No. 16 was obtained by sintering the sample No. 15 at a higher firing temperature. The D90 value was 0.25 μm or more and the electrostriction was as large as 0.079%.
試料番号6は、電歪は問題ないレベルであるが、第2の領域のD50値が0.05μm未満であるため、誘電率が480と低く、かつ温度特性が−29.2%と悪いため、好ましくない。   Sample No. 6 is at a level where electrostriction is not a problem, but because the D50 value in the second region is less than 0.05 μm, the dielectric constant is low as 480 and the temperature characteristic is as low as −29.2%. It is not preferable.
[実施例2] 本実施例は、誘電体セラミックの組成を様々に変化させ、その種々の特性に寄与する影響をみるものである。   [Example 2] In this example, the composition of the dielectric ceramic is changed in various ways, and the effect of contributing to the various characteristics is observed.
まず、BaCO3、SrCO3、CaCO3、TiO2、ZrO2を準備して、表2の(Ba1-x-yCaxSry)(Ti1-zZrz)O3の組成になるように秤量した後、ボールミルにより混合し、1100〜1200℃にて熱処理し、これを粉砕した。これにより、平均一次粒径0.1〜0.3μmの(Ba1-x-yCaxSry)(Ti1-zZrz)O3粉末を得た。 First, BaCO 3, to prepare the SrCO 3, CaCO 3, TiO 2 , ZrO 2, so that the composition of Table 2 (Ba 1-xy Ca x Sr y) (Ti 1-z Zr z) O 3 After weighing, they were mixed by a ball mill, heat-treated at 1100 to 1200 ° C., and pulverized. This gave (Ba 1-xy Ca x Sr y) (Ti 1-z Zr z) O 3 powder having an average primary particle diameter 0.1 to 0.3 [mu] m.
上記で得られた(Ba1-x-yCaxSry)(Ti1-zZrz)O3粉末100モル部に対し、平均一次粒径0.03μmのBaZrO3粉末を表2に示すaモル部加え、実施例1と同じ条件で24時間混合し、(Ba1-x-yCaxSry)(Ti1-zZrz)O3粉末にBaZrO3粉末を十分に分散させたスラリーを得た。 Obtained in the above (Ba 1-xy Ca x Sr y) (Ti 1-z Zr z) O 3 powder 100 parts by mol relative to, a molar showing a BaZrO 3 powder having an average primary particle diameter 0.03μm in Table 2 in addition parts, and mixed for 24 hours under the same conditions as in example 1 to give the (Ba 1-xy Ca x Sr y) (Ti 1-z Zr z) O 3 powder BaZrO 3 powder was thoroughly dispersed slurry .
次に、上記スラリー中に、Gd23、MgO、SiO2、V23、CuOおよびBaCO3粉末を、(Ba1-x-yCaxSry)(Ti1-zZrz)O3100モル部に対して、それぞれ表2に示すようにbモル部、cモル部、dモル部、0.5モル部、0.5モル部および3モル部添加し、4時間混合した。得られたスラリーを乾燥し、誘電体セラミックの原料粉末を得た。 Then, the above slurry, Gd 2 O 3, MgO, SiO 2, V 2 O 3, of CuO and BaCO 3 powder, (Ba 1-xy Ca x Sr y) (Ti 1-z Zr z) O 3 As shown in Table 2, b mole part, c mole part, d mole part, 0.5 mole part, 0.5 mole part and 3 mole part were added to 100 mole parts, and mixed for 4 hours. The obtained slurry was dried to obtain a dielectric ceramic raw material powder.
この誘電体セラミックの原料粉末を、実施例1と同様の方法にて成形体を作製た。この積層体を、窒素雰囲気中にて350℃で加熱し、バインダーを燃焼させた後、H2−N2−H2Oガスからなる酸素分圧10-10.5MPaの還元性雰囲気中にて、1220℃にて60分保持し、焼成されたセラミック積層体を得た。 A compact was produced from the dielectric ceramic raw material powder in the same manner as in Example 1. This laminate was heated at 350 ° C. in a nitrogen atmosphere to burn the binder, and then in a reducing atmosphere composed of H 2 —N 2 —H 2 O gas and having an oxygen partial pressure of 10 −10.5 MPa. It was held at 1220 ° C. for 60 minutes to obtain a fired ceramic laminate.
このセラミック積層体を実施例1と同じ工程を経て評価試料となる積層セラミックコンデンサを作製し、実施例1と同じ評価を行った。結果を表2に示す。   A multilayer ceramic capacitor serving as an evaluation sample was produced from the ceramic laminate through the same steps as in Example 1, and the same evaluation as in Example 1 was performed. The results are shown in Table 2.
試料番号17〜41の全試料において、第2の領域のD90値が0.25μm未満となり、電歪を0.055%以下となった。ただし、下記のように望ましい組成範囲外の試料は、誘電率または温度特性の面で好ましくない。   In all samples of sample numbers 17 to 41, the D90 value of the second region was less than 0.25 μm, and the electrostriction was 0.055% or less. However, a sample outside the desirable composition range as described below is not preferable in terms of dielectric constant or temperature characteristics.
すなわち、Ca置換量xが0.15より大きい試料番号18は、誘電率が420と低く、好ましくない。   That is, Sample No. 18 having a Ca substitution amount x larger than 0.15 is not preferable because the dielectric constant is as low as 420.
Sr置換量xが0.15より大きい試料番号20および25は、温度特性が−36.8%、−24.6%と悪く、好ましくない。   Sample Nos. 20 and 25 having an Sr substitution amount x greater than 0.15 are not preferable because their temperature characteristics are -36.8% and -24.6%.
誘電体セラミック中における合計のZr量を表す100z+aが0.30より大きい試料番号25および29は、誘電率が230、320と低く、また温度特性が−24.6%、−23.5%と悪く、好ましくない。   Sample numbers 25 and 29 in which 100z + a representing the total amount of Zr in the dielectric ceramic is greater than 0.30 have low dielectric constants of 230 and 320, and temperature characteristics of −24.6% and −23.5%. Bad and unfavorable.
希土類元素Rの含有量が、(Ba1-x-yCaxSry)(Ti1-zZrz)O3100モル部に対して30モル部を超える、すなわちGd23の含有量bが15を超える試料番号34は、誘電率が330と低く好ましくない。また、bが2より小さい試料番号30は、温度特性が−33.2%と悪く、好ましくない。 The content of the rare earth element R is greater than 30 parts by mole with respect to (Ba 1-xy Ca x Sr y) (Ti 1-z Zr z) O 3 100 molar parts, that is, the content b of Gd 2 O 3 Sample number 34 exceeding 15 is not preferable because the dielectric constant is as low as 330. Sample No. 30 where b is smaller than 2 is not preferable because the temperature characteristics are as bad as -33.2%.
MgOの含有量cが1未満である試料番号35は、温度特性が−35.5%と悪く、好ましくない。また、cが20を超える試料番号38は、誘電率が360と低く、温度特性が−29.2%と悪いため、好ましくない。   Sample No. 35 having an MgO content c of less than 1 is not preferable because its temperature characteristic is as bad as -35.5%. Sample number 38 with c exceeding 20 is not preferable because the dielectric constant is as low as 360 and the temperature characteristic is as low as −29.2%.
SiO2の含有量dが15より大きい試料番号41は、誘電率が470と低く、好ましくない。 Sample No. 41 having a SiO 2 content d greater than 15 is not preferable because the dielectric constant is as low as 470.
[実施例3] 本実施例は、ある特定の誘電体セラミック組成において、希土類元素の種類のみを様々に変化させた積層セラミックコンデンサを作製し、それによる電歪、誘電率および温度特性の変化を評価したものである。   [Example 3] In this example, in a specific dielectric ceramic composition, a multilayer ceramic capacitor in which only the kind of rare earth element was changed in various ways was manufactured, and changes in electrostriction, dielectric constant, and temperature characteristics caused thereby were measured. It has been evaluated.
まず、固相法により合成されたBaTiO3粉末を用意した。このBaTiO3粉末の平均一次粒径が0.15μmであり、c/a軸比は1.008であった。また、同様に固相法により合成された、平均一次粒径が0.03μmであるBaZrO3粉末を用意した。さらに、表3に示す種々の希土類元素の酸化物、MgO、MnO2、SiO2およびBaCO3粉末を用意した。 First, BaTiO 3 powder synthesized by a solid phase method was prepared. The average primary particle size of the BaTiO 3 powder was 0.15 μm, and the c / a axial ratio was 1.008. Similarly, a BaZrO 3 powder having an average primary particle size of 0.03 μm synthesized by a solid phase method was prepared. Furthermore, oxides of various rare earth elements shown in Table 3, MgO, MnO 2 , SiO 2 and BaCO 3 powder were prepared.
次に、上記のBaTiO3粉末とBaZrO3粉末を、実施例1と同じ条件にて混合し、BaTiO3粉末にBaZrO3粉末を十分に分散させたスラリーを得た。BaTiO3100モル部に対するBaZrO3量は6モル部であった。 Next, the BaTiO 3 powder and the BaZrO 3 powder were mixed under the same conditions as in Example 1 to obtain a slurry in which the BaZrO 3 powder was sufficiently dispersed in the BaTiO 3 powder. The amount of BaZrO 3 with respect to 100 mol parts of BaTiO 3 was 6 mol parts.
次に、上記スラリー中に、表3に示す希土類元素の酸化物、MgO、MnO2、SiO2およびBaCO3粉末を、BaTiO3100モル部に対して、それぞれ希土類元素換算で7モル部、3モル部、0.6モル部、6モル部および0.5モル部添加し、さらに4時間混合した。 Next, rare earth element oxides, MgO, MnO 2 , SiO 2 and BaCO 3 powder shown in Table 3 are added to the slurry in an amount of 7 mole parts, 3 parts in terms of rare earth elements with respect to 100 mole parts of BaTiO 3 , respectively. Mole parts, 0.6 mole parts, 6 mole parts and 0.5 mole parts were added and mixed for another 4 hours.
得られたスラリーを乾燥し、誘電体セラミックの原料粉末を得て、その後は実施例1と同じ工程を経て、H2−N2−H2Oガスからなる酸素分圧10-10.5MPaの還元性雰囲気中にて、1220℃にて60分保持し、焼成されたセラミック積層体を得た。その後も実施例1と同じを工程を経て積層セラミックコンデンサを作製し、評価試料として試料番号42〜59の試料を得た。 The obtained slurry was dried to obtain a raw material powder of a dielectric ceramic, and thereafter subjected to the same process as in Example 1, followed by reduction with an oxygen partial pressure of 10 −10.5 MPa made of H 2 —N 2 —H 2 O gas. Was held at 1220 ° C. for 60 minutes in a neutral atmosphere to obtain a fired ceramic laminate. Thereafter, through the same process as in Example 1, a multilayer ceramic capacitor was produced, and samples Nos. 42 to 59 were obtained as evaluation samples.
実施例1と同じ測定条件にて同じ評価項目を評価した結果を表3に示す。   Table 3 shows the results of evaluating the same evaluation items under the same measurement conditions as in Example 1.
試料番号42〜59の全試料において、第2の領域のD90値が0.25μm未満となり、電歪が0.055%以下となった。また、500以上の誘電率と、±22%より良好な温度特性を得た。以上より本発明の誘電体セラミックは、種々の希土類元素においても所望の特性を達成し得るものである。   In all samples of sample numbers 42 to 59, the D90 value in the second region was less than 0.25 μm, and the electrostriction was 0.055% or less. Further, a dielectric constant of 500 or more and temperature characteristics better than ± 22% were obtained. As described above, the dielectric ceramic of the present invention can achieve desired characteristics even in various rare earth elements.
本発明の一実施形態による積層セラミックコンデンサ1を図解的に示す断面図である。1 is a cross-sectional view schematically showing a multilayer ceramic capacitor 1 according to an embodiment of the present invention. 本発明の誘電体セラミックの、任意の面における断面を模式的に示した図である。It is the figure which showed typically the cross section in the arbitrary surfaces of the dielectric ceramic of this invention. 本発明の比較例における誘電体セラミックの、任意の面における断面を模式的に示した図である。It is the figure which showed typically the cross section in the arbitrary surfaces of the dielectric material ceramic in the comparative example of this invention. 本発明の誘電体セラミックの製造方法の一実施形態における、BaTiO3粉末粒子とBaZrO3粉末粒子が十分に分散したときの様子を、模式的に示した図である。In an embodiment of the dielectric ceramic manufacturing method of the present invention, the state in which BaTiO 3 powder particles and BaZrO 3 powder particles were sufficiently dispersed, a diagram schematically showing. 実施例1の試料番号3および14の、第2の領域の直径の分布における累積分布曲線を示す図である。It is a figure which shows the cumulative distribution curve in the distribution of the diameter of the 2nd area | region of the sample numbers 3 and 14 of Example 1. FIG.
符号の説明Explanation of symbols
1 積層セラミックコンデンサ
3 誘電体セラミック層
4,5 内部電極
8,9 外部電極
11,21 主相粒子
12,22 第1の領域
13,23 第2の領域
31 BaTiO3粉末粒子
32 BaZrO3粉末粒子
1 multilayer ceramic capacitor 3 dielectric ceramic layers 4 and 5 the internal electrodes 8 and 9 the external electrode 11, 21 the main phase grains 12, 22 first regions 13, 23 second region 31 of the BaTiO 3 powder particles 32 BaZrO 3 powder particles

Claims (5)

  1. (Ba 1-x-y Ca x Sr y )(Ti 1-z Zr z )O 3 (ただし、0≦x+y≦0.15,0≦z≦0.3)を含み、かつ、前記(Ba 1-x-y Ca x Sr y )(Ti 1-z Zr z )O 3 100モル部に対し、希土類元素R(Y,La,Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb,Luの少なくとも1種)を4〜30モル部、BaZrO 3 を2〜30(ただし、100zとの合計値が30を超えない)モル部含む、組成を有する、誘電体セラミックにおいて、
    前記誘電体セラミックの主相粒子が、前記(Ba 1-x-y Ca x Sr y )(Ti 1-z Zr z )O 3 および前記希土類元素Rを含むぺロブスカイト構造からなる固溶体であり、
    前記主相粒子が、2つの領域、すなわち前記希土類元素の濃度が高い第1の領域と前記希土類元素の濃度が低い第2の領域から構成され、前記第1の領域における希土類元素の平均濃度が、前記領域第2の領域における希土類元素の平均濃度に対し、モル比で3倍以上であるとともに、
    前記誘電体セラミックの断面を観察したとき、前記第2の領域の直径の分布におけるD90値が0.25μm未満であることを特徴とする、誘電体セラミック。
    (Ba 1-xy Ca x Sr y) (Ti 1-z Zr z) O 3 ( however, 0 ≦ x + y ≦ 0.15,0 ≦ z ≦ 0.3) includes, and the (Ba 1-xy Ca x Sr y) (relative to Ti 1-z Zr z) O 3 100 molar parts, the rare earth element R (Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm , Yb, Lu) in a dielectric ceramic having a composition comprising 4 to 30 mol parts and 2 to 30 mol parts of BaZrO 3 (where the total value with 100z does not exceed 30) ,
    Wherein the dielectric ceramic main phase particles, a solid solution composed of the (Ba 1-xy Ca x Sr y) (Ti 1-z Zr z) O 3 , and perovskite structure containing the rare earth element R,
    The main phase particles are composed of two regions, that is, a first region where the concentration of the rare earth element is high and a second region where the concentration of the rare earth element is low, and the average concentration of the rare earth element in the first region is The molar ratio of the rare earth element in the second region is not less than 3 times, and
    When the cross section of the dielectric ceramic is observed, the D90 value in the diameter distribution of the second region is less than 0.25 μm.
  2. 前記断面を観察したとき、前記第2の領域の直径の分布におけるD50値が0.05μm以上である、請求項に記載の誘電体セラミック。 When said cross section is observed, the D50 value in the distribution of the diameter of the second region is 0.05μm or more, the dielectric ceramic of claim 1.
  3. 前記ABO3100モル部に対し、Mgを1〜20モル部、Siを1〜15モル部含有する、請求項1または2に記載の誘電体セラミック。 The dielectric ceramic according to claim 1 or 2 , comprising 1 to 20 mol parts of Mg and 1 to 15 mol parts of Si with respect to 100 mol parts of the ABO 3 .
  4. (Ba 1-x-y Ca x Sr y )(Ti 1-z Zr z )O 3 (ただし、0≦x+y≦0.15,0≦z≦0.3)を含み、かつ、前記(Ba 1-x-y Ca x Sr y )(Ti 1-z Zr z )O 3 100モル部に対し、希土類元素R(Y,La,Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb,Luの少なくとも1種)を4〜30モル部、BaZrO 3 を2〜30(ただし、100zとの合計値が30を超えない)モル部含む、組成を有する、誘電体セラミックの製造方法であって、

    (Ba 1-x-y Ca x Sr y )(Ti 1-z Zr z )O 3 (ただし、0≦x+y≦0.15,0≦z≦0.3)を主成分とする第1の原料粉末、BaZrO3を主成分とする第2の原料粉末、および少なくとも希土類化合物を含む第3の原料粉末を用意する工程と、
    前記第1の原料粉末および前記第2の原料粉末を液中で混合、分散し、その後前記液中に前記第3の原料粉末を添加、混合し、乾燥して第4の原料粉末を得る工程と、
    前記原料粉末4を成形し、焼成する工程を備える誘電体セラミックの製造方法であって、
    前記第2の原料粉末の平均一次粒径が、前記第1の原料粉末の平均一次粒径の1/30〜1/3であることを特徴とする、誘電体セラミックの製造方法。
    (Ba 1-xy Ca x Sr y) (Ti 1-z Zr z) O 3 ( however, 0 ≦ x + y ≦ 0.15,0 ≦ z ≦ 0.3) includes, and the (Ba 1-xy Ca x Sr y) (relative to Ti 1-z Zr z) O 3 100 molar parts, the rare earth element R (Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm , Yb, Lu) 4-30 mol parts, BaZrO 3 2-30 (however, the total value with 100z does not exceed 30) mol dielectric , and a method for producing a dielectric ceramic having a composition Because

    (Ba 1-xy Ca x Sr y) (Ti 1-z Zr z) O 3 ( however, 0 ≦ x + y ≦ 0.15,0 ≦ z ≦ 0.3) first raw material powder mainly composed of, Preparing a second raw material powder mainly composed of BaZrO 3 and a third raw material powder containing at least a rare earth compound;
    Step of mixing and dispersing the first raw material powder and the second raw material powder in a liquid, and then adding, mixing and drying the third raw material powder in the liquid to obtain a fourth raw material powder When,
    A method for producing a dielectric ceramic comprising a step of forming and firing the raw material powder 4,
    The method for producing a dielectric ceramic, wherein an average primary particle size of the second raw material powder is 1/30 to 1/3 of an average primary particle size of the first raw material powder.
  5. 積層された複数の誘電体セラミック層と、前記誘電体セラミック層間に配置された内部電極と、前記内部電極に電気的に接続された外部電極とを備え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が、請求項1〜3のいずれかに記載の誘電体セラミックによって形成されてなることを特徴とする、積層セラミックコンデンサ。
    In a laminated ceramic capacitor comprising a plurality of laminated dielectric ceramic layers, internal electrodes disposed between the dielectric ceramic layers, and external electrodes electrically connected to the internal electrodes,
    A multilayer ceramic capacitor, wherein the dielectric ceramic layer is formed of the dielectric ceramic according to any one of claims 1 to 3 .
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