KR100826785B1 - Dielectric ceramic composition, process for producing the same, and stacked type ceramic capacitor - Google Patents

Abstract

When a complex oxide composed of only rare earth elements and Si is sintered in a reducing atmosphere and crystals grow, characteristics such as high temperature load reliability rapidly decrease.

The dielectric ceramic composition of the present invention is a perovskite comprising ABO ₃ (A-site includes Ba or Ba and at least one of Ca and Sr, and B-site includes Ti or Ti and at least one of Zr and Hf. Main phase particles mainly composed of sky-like crystals) and rare earth elements R (R is Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) At least one of)), Mg and Si, and secondary particles composed of a crystalline complex oxide containing R and Mg as a main component are present, and molar conversion is carried out when a part of Ti of B site is substituted with Zr. The relationship of 0.06 ≦ Zr / (Zr + Ti + Hf) ≦ 0.40 is established, and the content of R, Mg, and Si to ABO ₃ is, in terms of moles, R: 4 to 40%, Mg: 2 to 20%, and Si : 2 to 15%.

Multilayer Ceramic Capacitors, Dielectric Ceramic Layer, Internal Electrode, External Electrode

Description

Dielectric ceramic composition, method for manufacturing the same, and multilayer ceramic capacitor TECHNICAL FIELD

The present invention relates to a dielectric ceramic composition, a method of manufacturing the same, and a multilayer ceramic capacitor, and more particularly, to a dielectric ceramic composition having high reliability and an improved harmonic distortion rate, a method of manufacturing the same, and a multilayer ceramic capacitor.

As a conventional dielectric ceramic composition and multilayer ceramic capacitor of this kind, what was proposed in patent document 1, patent document 2, patent document 3, and patent document 4 is known, for example.

In Patent Document 1, a dielectric porcelain and a laminated electronic component have been proposed. The dielectric porcelain is a dielectric porcelain composed of main crystal grains composed of a perovskite complex oxide containing Ba, Ti, rare earth elements, Mg, and Mn, and grain boundary phases. And a crystal phase composed of a composite oxide containing Si. From this configuration, since γ-Y ₂ Si ₂ O ₇ is present as a crystal phase, the reliability in the high temperature load test can be improved even if it is thinned.

In Patent Document 2, a dielectric porcelain is proposed. The dielectric porcelain is represented by the composition formula {(Ba _{1 - x} Ca _x ) _m (Ti _{1 - y} Zr _y )} O ₃ (wherein 0.01≤x≤0.10, 0.15≤y≤0.25, 0.99≤m≤1.02). It is composed of a grain boundary phase containing the crystal grains, and a rare-earth element (other than Y ₂ O _3). From this configuration, even when firing in a reducing atmosphere, a dielectric porcelain having a high dielectric constant, a high insulation resistance value, and a low dielectric loss can be obtained. Further, even when the dielectric layer of the multilayer magnetic capacitor is thinned, reliability in the high temperature load test is poor. Can be reduced.

In addition, Patent Document 3 proposes a dielectric porcelain and its manufacturing method. The dielectric porcelain is a dielectric porcelain containing Ba, Ti, Mn, Y, and Mg, which is composed of main crystal grains composed of a perovskite complex oxide containing at least Ba and Ti, and grain boundaries containing at least Y and Mg. In addition, the Mn is substantially present only in the main crystal particles. From this configuration, since Mn exists only in the main crystal grains, the solid solution of Mg and Y in the main crystal grains is suppressed, the sinterability is improved, and the firing can be performed at a low temperature of 1200 ° C or lower. Since Mn exists only in the main crystal grains, the dielectric ceramic exhibits high insulation resistance.

Moreover, in patent document 4, a multilayer capacitor is proposed. In this multilayer capacitor, the dielectric layer is composed of crystal grains mainly composed of BaTiO ₃ and grain boundaries between the crystal grains. The grain boundaries of 80% or more of the total grain boundaries at the fracture surface of the dielectric layer are Si, rare earth elements, and alkaline earth. It consists of an amorphous containing a metal element and oxygen. From this configuration, even when fired at the firing conditions below the equilibrium oxygen partial pressure of Ni / NiO, excellent characteristics are exhibited at high temperature load life.

Patent Document 1: Japanese Patent Application Laid-Open No. 2002-265260

Patent Document 2: Japanese Patent Application Laid-Open No. 11-157928

Patent Document 3: Japanese Patent Application Laid-Open No. 2000-335966

Patent Document 4: Japanese Patent No. 3389408

However, in the case of the dielectric porcelain and the laminated electronic component described in Patent Literature 1, it can be seen that the composite oxide composed of only the rare earth element and Si rapidly decreases in characteristics such as high temperature load reliability when the crystal is grown by sintering in a reducing atmosphere. there was.

Further, in the case of the dielectric porcelain described in Patent Document 2, since a glass made of Si, Li, B and rare earth element oxide is prepared and added, a complex oxide of rare earth element and Si exists, and thus, the high temperature load test There is a fear that the reliability may decrease.

In the case of the dielectric porcelain described in Patent Literature 3, since Mn is dissolved in the main crystal, there is a problem that the solid solution of the rare earth element and Mg in the main crystal is suppressed and the distortion rate of the third harmonic is deteriorated.

In the case of the multilayer capacitor described in Patent Document 4, since the additive needs to be melted during the firing process, the reaction between the main component and the additive is likely to proceed, and it is difficult to control the temperature characteristics of the capacity. Since calcining and Si are performed simultaneously, there existed a problem that it cannot control generation | generation of the complex oxide of a rare earth element and Si.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object thereof is to provide a dielectric ceramic composition, a method of manufacturing the same, and a multilayer ceramic capacitor which can improve the reliability and improve the distortion rate of the third harmonic. have.

The present inventors have investigated the cause of the rapid deterioration of reliability when the complex oxide of rare earth element and Si is present. As a result, the complex oxide is likely to grow as a secondary particle having a large size in a reducing atmosphere, and thus rapid grain growth ( It was found that the reliability drastically decreased with the development. Therefore, the present inventors have found that the production of a complex oxide of rare earth elements and Si can be suppressed and prevented by employing a specific production method.

The present invention has been made on the basis of the above findings, wherein the dielectric ceramic composition according to claim 1 comprises ABO ₃ (where A site contains Ba or Ba and at least one of Ca and Sr, and B site is Ti or Ti). And a perovskite crystal containing at least one of Zr and Hf, and a main phase particle and a rare earth element R (where R is Y, La, Ce, Pr, Nd, At least one of Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu.) A dielectric ceramic composition comprising Mg and Si, wherein the rare earth elements R and Mg are the main components. Secondary particles made of a crystalline complex oxide are present, and when a part of Ti of the B-site is replaced by Zr, a relationship of 0.06 ≦ Zr / (Zr + Ti + Hf) ≦ 0.40 is established in molar terms. the rare earth element R, Mg, the content of the ABO ₃ of Si, on a molar basis, respectively, the rare earth Small R: 4~40%, Mg: 2~20%, Si: is characterized in that 2-15% of.

In the dielectric ceramic composition according to claim 2 of the present invention, in the invention according to claim 1, the crystalline composite oxide containing the rare earth elements R and Si as a main component is substantially free.

In the dielectric ceramic composition according to claim 3 of the present invention, in the invention according to claim 1 or 2, the columnar particles in which the rare earth elements R and Mg are dissolved are present, and the crystalline composite containing Mg and Si as a main component. It is characterized by containing an oxide.

In the dielectric ceramic composition according to claim 4 of the present invention, in the invention according to any one of claims 1 to ₃ , the metal element M is 0.5 mol% or more and 5 mol% or less with respect to the ABO ₃ . Represents at least one of Cr, V, Mn, Fe, Co, Ni, Cu, Nb, Mo, and W.).

The dielectric ceramic composition according to claim 5 of the present invention, in the invention according to any one of claims 1 to 4, contains Si and further contains at least one of Ca, Ba, B, and Li. It characterized in that it comprises a.

In the method for producing a dielectric ceramic composition according to claim 6 of the present invention, ABO ₃ (where A site contains any one of Ba or Ba and at least Ca and Sr, and B site includes Ti or Ti and at least Zr, Hf). And a rare earth element R (wherein R is Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, and Dy). At least one of Ho, Er, Tm, Yb, and Lu), and reacting Mg with each other to prepare a reactant having crystallinity, and mixing at least the ABO ₃ and the reactant. And a step of firing the raw material powder.

Further, the multilayer ceramic capacitor according to claim 7 of the present invention includes a plurality of stacked dielectric ceramic layers, a plurality of internal electrodes formed along a specific interface between the dielectric ceramic layers so as to obtain capacitance, and the internal A multilayer ceramic capacitor having an external electrode electrically connected to a specific one of the electrodes, wherein the dielectric ceramic layer is formed of the dielectric ceramic composition according to any one of claims 1 to 5.

Thus, the dielectric ceramic composition of the present invention comprises columnar particles composed mainly of ABO ₃ and rare earth elements R (where R is Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, At least one of Er, Tm, Yb, and Lu.), Mg, and Si.

ABO ₃ serving as a main component of the columnar particles is composed of a barium titanate (BaTiO ₃ ) -based perovskite complex oxide containing Ba at A site and Ti at B site. A site is a portion of Ba is substituted by Ca and / or Sr, B site is a portion of Ti is substituted by Zr and / or Hf. In particular, by substituting a part of Ti by Zr, it can be suitably used also as a dielectric material of a multilayer ceramic capacitor for high pressure applications having a large electric field strength.

Rare earth elements R (wherein R represents at least one of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu.), Mg and Si Are additives for improving the dielectric constant, temperature characteristics, Curie temperature, and the like of the dielectric materials.

For example, as shown schematically in FIG. 1, the dielectric ceramic composition of the present invention comprises secondary particles composed of columnar particles mainly composed of ABO ₃ and crystalline composite oxides mainly composed of rare earth elements R and Mg. In FIG. 1, the crystal structure which includes the part shown by blackening all over and the secondary phase particle | grains (part shown by the network point in FIG. 1) which consist of crystalline complex oxide which has Mg and Si as a main component is shown.

A crystalline complex oxide having the rare earth elements R and Mg of the secondary particles as a main component is produced by adding a complex oxide of the rare earth elements R and Mg prepared in advance in the firing step. By adding the complex oxide in the firing step, even if the rare earth elements R and Si are added, the formation of the complex oxide mainly containing the rare earth elements R and Si can be suppressed or prevented. As a result, the rare earth elements R and Si are prevented. There is substantially no crystalline composite oxide as a main component, and a dielectric ceramic composition can be obtained which can suppress or prevent a decrease in reliability. Here, the crystalline complex oxide mainly containing the rare earth elements R and Mg includes 8% or more of the rare earth elements R and Mg in the metal element ratio and 50% or more of the rare earth elements R and Mg in total ( Phase).

In addition, by adding a complex oxide of rare earth elements R and Mg, it is possible to promote the solid solution of the rare earth elements R and Mg in the columnar particles, thereby improving the reliability of the columnar particles and further improving the reliability as the dielectric material. . In addition, by adding a complex oxide of rare earth elements R and Mg, the rare earth elements R and Mg are dissolved in the columnar particles to improve the distortion rate of the third harmonic. The phases employed by the rare earth elements R and Mg of the columnar particles are indicated by diagonal lines.

On the other hand, crystalline complex oxides containing rare earth elements R and Mg as main components may generate reactants with Ti and Zr under firing conditions, but crystalline composites containing rare earth elements R and Mg, Ti and Zr as main components Even if an oxide is present, it does not reduce the effect of suppressing the production of a complex oxide mainly composed of the rare earth elements R and Si, and the effect of promoting the solid solution of the rare earth elements R and Mg in the columnar particles, and the rare earth elements R and Mg. The effect equivalent to the crystalline complex oxide which has as a main component is acquired.

The substitution rate [Zr / (Zr + Ti + Hf)] of Zr in the B site of ABO ₃ satisfies a relationship of 0.06 to 0.40 in terms of moles. When Zr / (Zr + Ti + Hf) is less than 0.06, the Curie point rises, the temperature characteristics deteriorate somewhat as a dielectric material, and when Zr / (Zr + Ti + Hf) exceeds 0.40, the dielectric constant slightly decreases.

The content of the rare earth elements R are, for ABO _3, in the range of 4-40% by mole. If the rare earth element R is less than 4 mol%, the phase (solid line portion in Fig. 1) dissolved in the main component of the columnar particles is reduced, so that the function of improving the third harmonic distortion rate is slightly lowered, and the rare earth element R is 40 mol. On the contrary, since the solid solution of the columnar particles increases to the main component, the dielectric constant decreases slightly, and the temperature characteristic deteriorates slightly.

The content of Mg is, with respect to ABO _3, in the range of from 2 to 20% by mole. If the Mg is less than 2 mol%, the solid solution phase in the main component of the columnar particles decreases, so that the function of improving the third harmonic distortion rate is slightly deteriorated. Because of the increase, the dielectric constant decreases slightly, and the temperature characteristic deteriorates slightly.

The Si content is, with respect to ABO _3, in the range of 2-15% by mole. If Si is less than 2 mol%, the sintering property is lowered, and the third harmonic distortion rate is slightly worsened. If Si is more than 15 mol%, on the contrary, it is oversintered and the temperature characteristic is slightly deteriorated. Even if the third harmonic distortion ratio deteriorates as described above, the characteristics and reliability as the dielectric material are not impaired.

Since the crystalline complex oxide containing the rare earth elements R and Si as a main component may lower the reliability as described above, it is preferable that the crystalline complex oxide be substantially absent. The fact that the crystalline complex oxide mainly containing the rare earth elements R and Si is substantially absent means that the rare earth elements R and Si are present due to the presence of the crystalline complex oxides of the rare earth elements R and Mg even if the crystalline complex oxide is present, for example. Refers to the presence (amount) to the extent that the influence of the complex oxide can be ignored.

In the present invention, by adding a complex oxide of rare earth elements R and Mg as described above, it is possible to obtain a dielectric ceramic composition substantially free of a crystalline complex oxide mainly composed of rare earth elements R and Si. Reliability can be improved. Moreover, the composite oxide of rare earth element R and Si worsens the distortion rate of a 3rd harmonic as a result of suppressing the solid solution of the rare earth element R to columnar particle | grains. However, in the dielectric ceramic composition of the present invention, since the complex oxide of rare earth elements R and Si is substantially absent, the distortion rate of the third harmonic does not deteriorate. Rather, as described above, rare earth elements R and Mg. The distortion rate of the third harmonic improves due to the presence of the complex oxide. Here, the crystalline complex oxide containing the rare earth elements R and Si as the main components refers to a phase in which the rare earth elements R and Si are contained in a metal element ratio of 25% or more, respectively, and Mg is 8% or less in total.

The crystalline composite oxide having Mg and Si as the main component of the secondary phase particles has the same function as the crystalline composite oxide having the rare earth elements R and Mg as a main component, and suppresses the formation of the complex oxide of the rare earth elements R and Si, In addition, the solid solution of the rare earth element R can be promoted to the columnar particles. Herein, the crystalline complex oxide containing Mg and Si as the main component includes 8% or more of Mg and Si in the metal element ratio, 50% or more of Mg and Si in total, and the rare earth element R is 8 The phase is less than or equal to%.

In addition, the dielectric ceramic composition of the present invention preferably contains 0.5 mol% or more and 5 mol% or less of the metal element M with respect to ABO ₃ . Even if the metal element M is less than 0.5 mol% or more than 5 mol%, high-temperature load reliability falls slightly. As the metal element M, for example, at least one of Cr, V, Mn, Fe, Co, Ni, Cu, Nb, Mo, and W may be appropriately selected and used, and two or more kinds may be appropriately selected and used.

In addition, the dielectric ceramic composition of the present invention preferably contains Si as the sintering aid, and at least one of Ca, Ba, B and Li is preferably included. By adding these sintering aids, the sintering temperature can be lowered.

In the method for producing a dielectric ceramic composition of the present invention, ABO ₃ (where A site contains any one of Ba or Ba and at least Ca and Sr, and B site includes Ti or Ti, at least Zr and Hf). In the step of producing a perovskite crystal containing one type), the perovskite crystal which is the basis of the dielectric ceramic composition is prepared.

At least the rare earth element R (where R represents at least one of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) is reacted with Mg In the step of producing a reactant having a crystallinity in part, the starting material of the dielectric ceramic composition of the present invention includes, in advance, a reactant of the rare earth elements R and Mg, that is, a part of the crystalline complex oxide of the rare earth elements R and Mg. A composite oxide is prepared. Thus, by preparing a composite oxide of rare earth element R and Mg as a starting material, the formation of the composite oxide of rare earth element R and Si added as a sintering aid in the step of firing the dielectric ceramic composition of the present invention can be prevented and prevented. have. In this step, in addition to the rare earth elements R and Mg, a plurality of other metal elements may be added and reacted. As the rare earth element R, at least one of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu can be selected and used. You can also use

In the step of preparing the raw material powder, the raw material powder is prepared by mixing at least ABO ₃ and an R-Mg reactant (complex oxide containing a crystalline complex oxide of a rare earth element R and Mg in part). Therefore, in addition to ABO ₃ and the R-Mg reactant, other metal oxides and the like may be appropriately selected and added as necessary.

In the step of firing the raw material powder, the dielectric ceramic composition of the present invention can be obtained by firing a raw material powder composed of at least ABO ₃ and a R-Mg reactant (a composite oxide containing a crystalline complex oxide of rare earth elements R and Mg). have. In the firing step, since the rare earth element R forms a crystalline composite oxide in advance with Mg, the generation of the composite oxide containing the rare earth elements R and Si as a main component can be suppressed and prevented, thereby improving the high temperature load reliability. A dielectric ceramic composition can be obtained.

Since the multilayer ceramic capacitor of the present invention uses the dielectric ceramic composition of the present invention as a dielectric material, temperature characteristics, high temperature load reliability, third harmonic distortion rate, and the like are improved.

Effect of the Invention

According to the inventions of claims 1 to 7, the dielectric ceramic composition, the manufacturing method thereof, and the multilayer ceramic capacitor which can improve the reliability and improve the distortion rate of the third harmonic can be provided. .

1 is a schematic diagram showing the crystal structure of the dielectric ceramic composition of the present invention.

2 is a cross-sectional view showing an embodiment of the multilayer ceramic capacitor of the present invention.

<Description of the code>

1: multilayer ceramic capacitor 2: dielectric ceramic layer

3A, 3B: internal electrode 4A, 4B: external electrode

EMBODIMENT OF THE INVENTION Hereinafter, one Embodiment of this invention is described, referring FIG. For example, as shown in FIG. 2, the multilayer ceramic capacitor 1 of the present embodiment has a dielectric ceramic layer 2 having a plurality of layers (five layers in the present embodiment) and the dielectric ceramic layer 2 respectively. A laminate having a plurality of first and second internal electrodes 3A and 3B arranged, and first and second external electrodes electrically connected to the internal electrodes 3A and 3B and formed at both ends of the laminate ( 4A, 4B).

As shown in FIG. 2, the first internal electrode 3A extends from one end (left end of FIG. 2) to the other end (right end) of the dielectric ceramic layer 2, and the second internal electrode 3B. The silver extends from the right end of the dielectric ceramic layer 2 to the vicinity of the left end. The first and second internal electrodes 3A and 3B are made of a conductive material. As this electroconductive material, any 1 type of metal chosen from nickel, nickel alloys, copper, a copper alloy, silver, and a silver alloy can be used preferably, for example. In addition, in order to prevent structural defects of the internal electrodes, a small amount of ceramic powder may be added to the conductive material.

As shown in FIG. 2, the first external electrode 4A is electrically connected to the first internal electrode 3A in the laminate, and the second external electrode 4B is the second internal electrode (in the laminate). It is electrically connected to 3B). The first and second external electrodes 4A and 4B can be formed of various conductive materials such as Ag and copper, which are known in the art. As the forming means of the first and second external electrodes 4A and 4B, conventionally known respective means can be appropriately employed.

In the case of the multilayer ceramic capacitor of the present embodiment, since it can be fired in a reducing atmosphere, an internal electrode can be formed using nonmetals such as nickel, nickel alloys, copper, and copper alloys.

<Example>

In this embodiment, the dielectric ceramic composition of the present invention used in the dielectric ceramic layer 2 was prepared, the multilayer ceramic capacitor of the present invention was produced using the dielectric ceramic composition, and the electrical characteristics of the multilayer ceramic capacitor were evaluated. .

Examples 1-15

In the present embodiment, 1 to 15, as an _{ABO 3 (Ca Ba 0 .94 Sr} 0 .04 0 .02) (Ti 0 .80 Zr 0 .20) rare earth elements using O ₃ and, as shown in Table 1 as an additional component Oxides (hereinafter referred to as "RO _x "), MgO, MnO ₂ , CuO, V ₂ O _5, and SiO ₂ were used.

(1) Preparation of (Ba Sr _{0 .94 0 .04 0 .02} Ca) (Ti _{0 .80 0 .20} Zr) O ₃

First, as starting materials _{BaCO 3, SrCO 3, CaCO 3} , TiO 2 , and preparing each powder of ZrO _2, and these starting materials (Ba Sr _{0 .94 0 .04 0 .02} Ca) (Ti _{0 .80} Zr _{0 .20)} O were weighed to be a _3, and mixed by a ball mill for these starting materials and subjected to a heat treatment at 1150 ℃, c / a axial ratio of 1.0087, an average particle diameter of 0.25㎛ (Ba _{0 .94} Sr _{0 .04} Ca _{0 .02)} (after synthesizing _{Ti 0 .80 Zr 0 .20) O} 3, this was ground.

(2) Preparation of 2RO _x -MgO-based reactant

Further, the oxides RO _x and MgO of the rare earth elements shown in Table 1 were each weighed so as to have a ratio of RO _x : MgO = 2: 1, mixed by a ball mill, heat treated at 1100 ° C, and an average particle diameter of 0.3. A 2RO _x -MgO based reactant was obtained. However, x is a value which varies with the valence of the rare earth element R. For example, when the rare earth element R is La, x = 3/2.

(3) Preparation of dielectric raw material powder

Then, 84.4% by mole of (Ba Sr _{0 .94 0 .04 0 .02} Ca) (Ti _{0 .80 0 .20} Zr) O _3, 8.4 mol% of 2RO _x -MgO based reactant, 1.7 mole% of MgO, A dielectric material powder was obtained by mixing 4.3 mol% SiO ₂ , 0.4 mol% MnO ₂ , 0.4 mol% CuO and 0.4 mol% V ₂ O ₅ by a ball mill.

(4) fabrication of multilayer ceramic capacitors

In Table 1, organic solvents, such as a polyvinyl butyral type binder and ethanol, were respectively added to the dielectric raw material powders shown in Examples 1-15, were wet-mixed by the ball mill, and the ceramic slurry was prepared. These ceramic slurries were formed into a sheet shape by the doctor blade method so that the thickness of the dielectric ceramic layer after firing was 3 m, thereby obtaining a rectangular ceramic green sheet. Subsequently, a conductive paste containing nickel (Ni) as the conductive powder was screen printed on these ceramic green sheets to form a conductive paste layer for constituting the internal electrode. The ceramic green sheet in which this conductive paste layer was formed was laminated | stacked in multiple sheets so that the side from which the conductive paste may be drawn may differ, and the green laminated body was obtained. This green laminate was heated to 350 ℃ in a nitrogen gas atmosphere, then the combustion of a binder, in 1250 ℃ in a reducing atmosphere consisting of 10 ^-9.0 MPa oxygen partial pressure of H ₂ gas, N ₂ gas and H ₂ O gases It baked for 2 hours and obtained the ceramic laminated body.

Cu paste containing glass frit is applied to both end surfaces of the ceramic laminate after firing, and the Cu paste is baked at a temperature of 700 ° C. in an N ₂ atmosphere to form an external electrode electrically connected to the internal electrode. The multilayer ceramic capacitors of Examples 1 to 15 made of the dielectric ceramic composition of the invention were obtained.

The external dimensions of the multilayer ceramic capacitors (Examples 1 to 15) thus obtained were 1.6 mm in width, 3.2 mm in length, and 0.8 mm in thickness, respectively, and the thickness of the dielectric ceramic layer interposed between the internal electrodes was 3 m. It was. The total number of effective dielectric ceramic layers was 100, and the area of the counter electrode per layer was 2.1 mm 2.

(5) Characterization of multilayer ceramic capacitors

For each of the multilayer ceramic capacitors of Examples 1 to 15, the dielectric constant epsilon, temperature characteristics, high temperature load life, and third harmonic distortion rate (THD) were measured, respectively, and the results are shown in Table 1 below. Further, the ceramic structure was analyzed for any fracture surface including the central portion of the multilayer ceramic capacitor.

Dielectric constant (epsilon) was measured on condition of the temperature of 25 degreeC, 1 kHz, and 1 Vrms. The change rate of the capacitance with respect to the temperature change is expressed as the temperature characteristic of the change rate at 125 ° C based on the capacitance at 25 ° C.

In the high temperature load test, a voltage of 50 V was applied at a temperature of 125 ° C., and the change over time of the insulation resistance was measured. The high temperature load test was performed on 100 multilayer ceramic capacitors, and it determined that the sample whose insulation resistance value was 100 micrometers or less until 1000 hours passed was faulty.

THD was measured under conditions of an input voltage of 1 V and 10 kHz using a component linearity tester CLT-20 (manufactured by Short Bridge). THD measured the 3rd harmonic (30 kHz) component (voltage _E30k ) which generate | occur | produces in a sample when the 10-kHz electric current (voltage _G10k ) flowed through a sample, and calculated | required by the following formula.

THD = 20Log (E _30k / G _10k ) [dB]

In addition, for the analysis of the ceramic structure, the composition of the secondary phase particles was confirmed by using wavelength dispersion X-ray analysis (WDX), and the results are shown in Table 1. In addition, confirmation of crystallinity is performed by X-ray diffraction analysis or electron beam diffraction analysis.

Comparative Examples 1-15

In Comparative Examples 1 to 15, (Ba _0.94 Sr _0.04 Ca _0.02 ) (Ti _0.80 Zr _0.20 ) O ₃ was used as ABO ₃ , and RO _x , MgO, MnO ₂ , CuO, V ₂ O _5, and SiO ₂ were used. In each of the comparative examples, 16.8 mol% of rare earth element oxides RO _x and 10.1 mol% of MgO were substituted for 8.4 mol% of 2RO _x -MgO-based reactants and 1.7 mol% of MgO in the above Examples. The multilayer ceramic capacitors of Comparative Examples 1 to 15 corresponding to Examples 1 to 15 were manufactured in the same order as those of the above-described Examples except that the multilayer ceramic capacitors of Examples 1 to 15 were used, and the multilayer ceramic capacitors of Comparative Examples 1 to 15 were manufactured. Evaluation similar to each said Example was performed, and the result is shown in Table 1. In addition, the stoichiometric ratio of each member element in each comparative example is the same as that of each Example.

Rare earth species Presence or absence of secondary phase based on R, Mg Presence or absence of secondary phase mainly containing R, Si ε Temperature characteristic 125 ℃ /% High temperature load test THD / dB Example 1 La U radish 330 -21.7 0/100 -92 Example 2 Ce U radish 340 -20.8 0/100 -90 Example 3 Pr U radish 360 -20.0 0/100 -87 Example 4 Nd U radish 370 -19.6 0/100 -86 Example 5 Sm U radish 370 -16.3 0/100 -86 Example 6 Eu U radish 390 -15.2 0/100 -85 Example 7 Gd U radish 400 -14.8 0/100 -83 Example 8 Tb U radish 420 -14.7 0/100 -81 Example 9 Dy U radish 430 -13.5 0/100 -80 Example 10 Y U radish 440 -12.9 0/100 -76 Example 11 Ho U radish 440 -12.8 0/100 -75 Example 12 Er U radish 480 -11.8 0/100 -75 Example 13 Tm U radish 470 -11.5 0/100 -73 Example 14 Yb U radish 500 -11.3 0/100 -73 Example 15 Lu U radish 510 -10.4 0/100 -71 Comparative Example 1 La radish U 680 -19.8 100/100 -82 Comparative Example 2 Ce radish U 720 -19.0 100/100 -81 Comparative Example 3 Pr radish U 780 -18.8 100/100 -76 Comparative Example 4 Nd radish U 860 -17.8 83/100 -73 Comparative Example 5 Sm radish U 860 -16.2 57/100 -73 Comparative Example 6 Eu radish U 910 -15.0 52/100 -71 Comparative Example 7 Gd radish U 950 -14.7 34/100 -71 Comparative Example 8 Tb radish U 990 -14.3 33/100 -68 Comparative Example 9 Dy radish U 1000 -13.2 25/100 -66 Comparative Example 10 Y radish U 1130 -12.9 23/100 -65 Comparative Example 11 Ho radish U 1140 -12.7 22/100 -63 Comparative Example 12 Er radish U 1180 -11.7 22/100 -63 Comparative Example 13 Tm radish U 1190 -11.5 18/100 -62 Comparative Example 14 Yb radish U 1220 -10.8 11/100 -62 Comparative Example 15 Lu radish U 1270 -10.3 12/100 -61

According to the result shown in Table 1, it turned out that it is the following.

According to the results of WDX, the secondary ceramic particles composed of the rare earth elements R and Mg as the main components were shown in the dielectric ceramic layers of the multilayer ceramic capacitors of Examples 1 to 15, but the composites containing the rare earth elements R and Si as main components Secondary particles made of oxide were not seen. On the other hand, in the dielectric ceramic layer of the multilayer ceramic capacitors of Comparative Examples 1 to 15, secondary phase particles made of a complex oxide containing rare earth elements R and Si were shown, but composed of a composite oxide containing mainly rare earth elements R and Mg. Secondary particles were not visible.

In addition, in Examples 1 to 15, in the firing step, the addition of a composite oxide composed of the rare earth elements R and Mg prepared in advance can suppress or prevent the formation of the composite oxide consisting of the rare earth elements R and Si. The degradation of the reliability in the high temperature load test was suppressed. The composite oxide containing the rare earth elements R and Mg and the columnar particles in which the rare earth elements R and Mg are dissolved have high reliability, and even in the dielectric ceramic layer, the reliability (high temperature load reliability) in the high temperature load test is improved.

On the other hand, in Comparative Examples 1 to 15, there was no composite oxide containing the rare earth elements R and Mg as the main component, and the presence of the composite oxide containing the rare earth elements R and Si as the main component lowered the high temperature load reliability.

In addition, about THD, since the value fluctuates according to the kind of rare earth element R, it cannot compare uniformly, However, when each Example and each comparative example are compared with the same rare earth element R and the addition amount, each implementation is carried out. In the example, THD was reduced compared with each comparative example by production | generation of the secondary particle which has rare earth elements R and Mg as a main component.

Examples 16-21

In this embodiment 16-21, the Ba (Ti _{0 .94 0 .06} Zr) O _3, and using, as an additional component a rare earth element oxide RO _x shown in Table 2, MgO, MnO _2, SiO ₂ as an ABO ₃ Used.

(1) Preparation of Ba (Ti _{0 .94 0 .06} Zr) O ₃

First, the BaCO _3, TiO ₂ and wheat preparing each powder of ZrO _2, and view them after the starting materials were weighed so that Ba (Ti _{0 .94 0 .06} Zr) O _3, these starting materials as a starting material The mixture was mixed with each other, and heat treatment was performed at 1150 ° C. to synthesize Ba (Ti _0.94 Zr _0.06 ) O ₃ having a c / a axis ratio of 1.011 and an average particle diameter of 0.2 μm, followed by grinding.

(2) Preparation of 3RO _x -MgO-based reactant

In addition, the rare earth element oxides RO _x and MgO shown in Table 2 were each weighed in a molar ratio such that RO _x : MgO = 3: 1, mixed by a ball mill, and heat-treated at 1100 ° C to obtain an average particle diameter of 0.3 µm. A reaction product of 3RO _x -MgO system was obtained. In Example 21, two kinds of rare earth element oxides RO _x (combination of 4Gd and 2Nd) were used.

(3) Preparation of dielectric raw material powder

Then, mixed by a ball mill to MnO ₂ of 95.7 mol% of Ba (Ti _{0 .94 0 .06} Zr) O _3, 1.9 mol% of 3RO _x -MgO based reactant, 1.9 mole% of SiO ₂ and 0.5 mol% To obtain a dielectric material powder.

(4) fabrication of multilayer ceramic capacitors

In Table 2, organic solvents, such as a polyvinyl butyral system binder and ethanol, were respectively added to the dielectric raw material powders shown in Examples 16-21, were wet-mixed by the ball mill, and the ceramic slurry was prepared. These ceramic slurries were molded into a sheet shape by the doctor blade method so that the thickness of the dielectric ceramic layer after baking became 2 m, thereby obtaining a rectangular ceramic green sheet. Subsequently, the conductive paste containing Ni as an electroconductive powder was screen-printed on these ceramic green sheets, and the electrically conductive paste layer for forming an internal electrode was formed. The ceramic green sheet in which this conductive paste layer was formed was laminated | stacked in multiple sheets so that the side from which the conductive paste may be drawn may differ, and the green laminated body was obtained. This green laminate was heated to 350 ℃ in a nitrogen gas atmosphere, then the combustion of a binder, in 1250 ℃ in a reducing atmosphere consisting of 10 ^-10.5 MPa oxygen partial pressure of H ₂ gas, N ₂ gas and H ₂ O gases It baked for 2 hours and obtained the ceramic laminated body.

Cu paste containing glass frit is applied to both end surfaces of the ceramic laminate after firing, and the Cu paste is baked at a temperature of 700 ° C. in an N ₂ atmosphere to form an external electrode electrically connected to the internal electrode. The multilayer ceramic capacitors of Examples 16 to 21 made of the dielectric ceramic composition of the invention were obtained.

The external dimensions of the multilayer ceramic capacitors (Examples 16 to 21) thus obtained were 1.2 mm in width, 2.0 mm in length, and 1.2 mm in thickness, respectively, and the thickness of the dielectric ceramic layer interposed between the internal electrodes was 2.0 m. It was. The total number of effective dielectric ceramic layers was 300, and the area of the counter electrode per layer was 1.0 mm 2.

(5) Characterization of multilayer ceramic capacitors

For each of the multilayer ceramic capacitors of Examples 16 to 21, the dielectric constant?, The temperature characteristic, the high temperature load life, and the third harmonic distortion factor THD were measured in the same manner as in each of the above examples, and the results are shown in Table 2. It was. On the other hand, about the high temperature load test, the high temperature load life was measured similarly to each said Example except having applied the voltage of 32V. In addition, the arbitrary fracture surface including the center part of a multilayer ceramic capacitor was analyzed similarly to each said Example, the ceramic structure was analyzed, the composition of the secondary particle was confirmed, and the result is shown in Table 2.

Rare earth species Presence or absence of secondary phase based on R, Mg Presence or absence of secondary phase mainly containing R, Si ε Temperature characteristic 125 ℃ /% High temperature load test THD / dB Example 16 Ce U radish 1180 -19.2 0/100 -75 Example 17 Gd U radish 1540 -16.3 0/100 -73 Example 18 Dy U radish 1690 -14.2 0/100 -70 Example 19 Er U radish 1800 -12.5 0/100 -68 Example 20 Yb U radish 1920 -11.2 0/100 -66 Example 21 4Gd, 2Nd U radish 1370 -16.8 0/100 -75

According to the result shown in Table 2, it turned out that it is the following.

In other words, when the Zr of the main component ABO ₃ is different, the results of the high temperature load test show that the reliability and the like are improved. Moreover, also in Example 21 in which two rare-earth elements R were added, it turns out that high temperature load reliability etc. improve. Therefore, even if two or more types of rare earth elements R are added, it is estimated that the result of the same tendency is obtained.

Example 22

In the embodiment 22, in place of the _x 3RO -MgO-based reaction in Example _{16~21, Gd0 3/2, MgO} , SiO 2 , respectively 3: 1 were weighed so that a molar ratio of 1, a ball mill to the mixture, and by heat treatment at _{1100 ℃, 3GdO 3/2 -MgO} -SiO 2 system the reaction product thus prepared, of 97.5 mol% _{Ba (Ti 0.94 Zr 0.06) O} 3, 2.0 mol% 3GdO _3/2 -MgO A dielectric material powder was obtained by mixing -SiO ₂ -based reactant and 0.5 mol% MnO ₂ by a ball mill. Subsequently, multilayer ceramic capacitors were produced in the same order as in Examples 16 to 21, and the same evaluations as those of the multilayer ceramic capacitors were made, and the results are shown in Table 3.

Comparative Example 16

Comparative Example 16 In Examples 16~21 3RO _x -MgO system without preparing a reaction product, of 92.9 mol% Ba (Ti _{0 .94 0 .06} Zr) O _3, 2.8 mol% of Gd ₂ O ₃ in the Using a dielectric material powder obtained by mixing 1.9 mol% MgO, 1.9 mol% SiO ₂ and 0.5 mol% MnO ₂ by a ball mill, a multilayer ceramic capacitor was produced in the same order as in Examples 16 to 21. The same evaluations as those of the multilayer ceramic capacitors were made, and the results are shown in Table 3.

Comparative Example 17

In this comparative example 17, an embodiment in place of the _x 3RO -MgO-based reactants in 16~21, GdO _3/2 and a SiO ₂ 3: were weighed so that the molar ratio of 1, and mixed by a ball mill, by heat treatment at 1100 ℃, 3GdO _3/2 -SiO and to prepare a reaction product of _{the second} order, of 95.7 mol% _{Ba (Ti 0.94 Zr 0.06) O} 3, 1.9 mol% 3GdO _3/2 -SiO ₂ based reactant, 1.9 mole Using a dielectric material powder obtained by mixing% MgO and 0.5 mol% MnO ₂ by a ball mill, a multilayer ceramic capacitor was produced in the same order as in Examples 16 to 21, and the same evaluation as that of each multilayer ceramic capacitor was performed. The results are shown in Table 3.

Comparative Example 18

In this comparative example 18, an embodiment in place of the _x 3RO -MgO-based reactants in 16~21, GdO _3/2 and a SiO ₂ 3: were weighed so that the molar ratio of 1, and mixed by a ball mill, this mixture and melted at 1500 ℃, the melt of the glass cullet (cullet) to put into water (水中), and the glass cullet was crushed to prepare a glass powder in 3GdO _3/2 -SiO ₂ system. Next, 95.7 mol% of Ba (Ti _{0 .94 0 .06} Zr) O _3, 1.9 mol% of 3GdO _3/2 -SiO ₂ based glass powder, 1.9 mol% of MgO and 0.5 mol% MnO ₂ in a ball mill The multilayer ceramic capacitors were produced in the same order as in Examples 16 to 21, using the dielectric material powders obtained by mixing in the same manner as described above, and the same evaluations as those of the multilayer ceramic capacitors were made.

Comparative Example 19

In this comparative example 19, example embodiments are weighed _{16~21 Ba (Ti 0 .94 Zr 0} .06) O 3 BaCO 3, TiO 2 and ZrO ₂ so that a composition of the, and, 3 mole% with respect to the Ba Gd ₂ O ₃ and 2 mol% of MgO were weighed, mixed by a ball mill, and heat-treated at 1150 ° C to obtain a principal component crystal. In the same procedure as in Examples 16 to 21, using a dielectric material powder obtained by mixing 2.0 mol% of SiO ₂ and 0.5 mol% of MnO ₂ by a ball mill to 97.5 mol% in terms of Ba of the main component crystals. A multilayer ceramic capacitor was produced, the same evaluation as that of each multilayer ceramic capacitor was performed, and the results are shown in Table 3.

Comparative Example 20

In this Comparative Example 20, Examples 16-21 and weighed according to the BaCO _3, TiO ₂ and ZrO _2, so that a composition of Ba (Ti _{0 .94 0 .06} Zr) O _3, In addition, the 0.5 mol% with respect to the Ba After weighing, MnO ₂ was mixed by a ball mill and heat-treated at 1150 ° C. to obtain a main component crystal. A dielectric material powder obtained by mixing 2.8 mol% Gd ₂ O ₃ , 1.9 mol% MgO and 1.9 mol% SiO ₂ with a ball mill to 93.4 mol% in terms of Ba of the main component crystal was carried out. Multilayer ceramic capacitors were produced in the same order as in Examples 16 to 21, and the same evaluations as those of the multilayer ceramic capacitors were made, and the results are shown in Table 3.

Comparative Example 21

In the Comparative Example 21, Examples 16-21 in, 94.7 mol% of Ba (Ti _{0 .94 0 .06} Zr) O _3, Gd ₂ O ₃ 2.8 mol%, 2.0 mol% MgO and 0.5 mol% After weighing, MnO ₂ was mixed by a ball mill, dried to obtain main component crystals coated with Gd ₂ O ₃ , MgO and MnO ₂ . With respect to 100 moles of Ba in terms of the main component determined to prepare a multilayer ceramic capacitor in the same order as in Example 16-21, using the dielectric raw material powder obtained by mixing by a ball mill to SiO ₂ of 2 moles, each stack Evaluation similar to the ceramic capacitor was performed, and the result is shown in Table 3.

Comparative Example 22

In this comparative example 22, in place of the _x 3RO -MgO-based reaction in Example 16~21, Gd0 _3/2 and the MgO and SiO ₂ and Li ₂ CO _{3 3:} A weighed so that the molar ratio of 1: 1 then, it was mixed by means of a ball mill, heat treated at _{1100 ℃, 3GdO 3/2 -MgO} -SiO 2 -Li 2 O system to prepare a reaction product, and 97.5 mol% Ba (Ti _{0 .94 0 .06} Zr) O _3, the 2.0 _{mol% 3GdO 3/2 -MgO-SiO} 2 -Li 2 O -based reactants and by using the obtained dielectric material powder is mixed by a ball mill to MnO ₂ of 0.5 mol%, the same as in example 16-21 A multilayer ceramic capacitor was produced in the order, the same evaluation as that of each multilayer ceramic capacitor was performed, and the result is shown in Table 3.

Calcination Presence or absence of secondary phase based on R, Mg Presence or absence of secondary phase mainly containing R, Si ε Temperature characteristic 125 ℃ /% High temperature load test THD / dB Example 22 Gd-Mg-Si U U 1680 -15.7 2/100 -71 Comparative Example 16 radish radish U 1640 -15.9 32/100 -65 Comparative Example 17 Gd-Si radish U 1720 -15.2 64/100 -62 Comparative Example 18 Gd-Si Glass radish U 1690 -15.4 88/100 -62 Comparative Example 19 radish radish radish 3620 -86.3 8/100 -58 Comparative Example 20 radish radish U 1860 -13.1 23/100 -63 Comparative Example 21 radish radish U 1590 -15.4 28/100 -66 Comparative Example 22 Gd-Mg-Si-Li radish radish 1470 -14.3 27/100 -61

According to the result shown in Table 3, it turned out that it is the following.

That is, when the rare earth elements R, Mg and Si are calcined and added as in Example 22, both of the secondary phase particles having the rare earth elements R and Mg as main components and the secondary phase particles having the rare earth elements R and Si as main components Because of this, a small THD value was obtained. In this case, even if there are secondary particles mainly composed of rare earth elements R and Si, secondary particles having rare earth elements R and Mg as a main component are small in comparison with secondary particles having rare earth elements R and Mg as main components. Due to the excellent effect of improving the high-temperature load reliability due to this, the reliability is inferior to the case where the secondary phase particles mainly containing the rare earth elements R and Si are substantially absent, but can be sufficiently practical by lowering the rated voltage. Can be said.

When the calcined product (reactant) of the rare earth elements R and Mg is not added as in Comparative Example 16, secondary particles having the rare earth elements R and Mg as the main component are not produced, and 2 having the rare earth elements R and Si as the main component Since the on-vehicle particles were produced, the THD and the high temperature load reliability deteriorated.

In addition, when calcined products (reactants) of the rare earth elements R and Si were prepared as in Comparative Example 17, the abundance ratio of secondary phase particles mainly containing the rare earth elements R and Si increased compared to Comparative Example 16, resulting in THD and high temperature load. Reliability worsened.

Also in Comparative Example 18, as in Comparative Example 17, it was found that the ratio of the secondary phase particles mainly containing the rare earth elements R and Si was high, and the THD and high temperature load reliability were deteriorated.

In the comparative example 19, since rare earth elements R and Mg were added at the time of synthesis | combination of a main crystal, Gd and Mg solid-solution in the whole main crystal, and the temperature characteristic of a capacitance deteriorated significantly. In addition, since there are no secondary particles having the rare earth elements R and Mg as main components, sufficient high temperature load reliability was not obtained.

In Comparative Example 20, since Mn was dissolved in the main crystal, solid solution of the rare earth elements R and Mg in the main crystal was suppressed and THD deteriorated. In addition, since the rare earth elements R and Mg are not calcined, secondary particles having the rare earth elements R and Si as main components are formed, and the high temperature load reliability is lowered.

In the comparative example 21, since the rare earth element R does not form a compound with Mg, the secondary phase particle which has a rare earth element R and Mg as a main component does not produce | generate, but the secondary phase particle which has a rare earth element R and Si as a main component produces | generates. Thus, THD and high temperature load reliability deteriorated.

In Comparative Example 22, since there were no crystalline secondary particles mainly composed of rare earth elements R and Mg, THD and high temperature load reliability deteriorated. This is because when Li enters, the secondary phase is vitrified and it is not crystallized.

Example 23

In Example 23, 95.7 mol% of Ba (Ti _0.94 Zr _0.06 ) O ₃ , 1.9 mol% of 3RO _x -MgO-based reactant, 1.9 mol% of SiO ₂ , and 0.5 mol in Examples 16 to 22 In the process of mixing% MnO ₂ with a ball mill, a dielectric raw powder in which 1 wt% of 15Li-30B-10Ba-5Ca-40Si-O _x glass was added to the main crystal was used. Multilayer ceramic capacitors were produced in the same order as in 16 to 22, the evaluations were performed, and the results are shown in Table 4 below. The firing temperature was 1000 ° C. and the oxygen partial pressure was 10 ^−11.5 MPa.

Presence or absence of secondary phase based on R, Mg Presence or absence of secondary phase mainly containing R, Si ε Temperature characteristic 125 ℃ /% High temperature load test THD / dB Example 23 U radish 1200 -14.1 0/100 -72

According to the result shown in Table 4, sufficient sinterability was obtained at low temperature of 1000 degreeC, and the characteristic which has no problem in reliability etc. was obtained.

Examples 24-29 and Reference Examples 1-10

In this embodiment 24-29 and Reference Examples 1 to 10, as an ABO _{3 GdO 3/2, MgO, MnO} 2, SiO 2 as the use of Ba (Ti _{0 .94 0 .06} Zr) O _3, and adding ingredient Used. In the present example and the reference example, the influence of the substitution rate of Zr [= Zr / (Zr + Ti + Hf)] and the content rate of rare earth elements R, MgO, and SiO with respect to ABO ₃ was investigated.

(1) Preparation of Ba (Ti _{0 .94 0 .06} Zr) O ₃

First, as starting materials BaCO _3, TiO _2, and preparing each powder of ZrO _2, and those after the starting materials were weighed so that a composition of Ba (Ti _{0 .94 0 .06} Zr) O _3, to see these starting materials and mixed by a mill, subjected to a heat treatment at 1000~1300 ℃, and then synthesize Ba (Ti _{0 .94 0 .06} Zr) O _3, this was ground.

₍₂₎ 4GdO _3/2 Preparation of -MgO-based reaction

Further, the rare earth element oxide GdO _3/2 and MgO to the mole ratio in GdO _3/2: After the respective weighed to be 1, and mixed by a ball mill, heat treated at 1100 ℃, average particle diameter 0.3㎛: MgO = 4 4GdO _3/2 to obtain a reaction product of -MgO system.

(3) Preparation of dielectric raw material powder

Then, 100 mol of _{Ba (Ti 0 .94 Zr 0 .06} ) with respect to the O _3, As shown in Table 5, b mol of 4GdO _3/2 -MgO type of reaction, c mol of SiO _2, MnO d mol ₂ and emol MgO were mixed by a ball mill to obtain a dielectric material powder.

(4) fabrication of multilayer ceramic capacitors

In Table 5, organic solvents such as polyvinyl butyral binder and ethanol were respectively added to the dielectric raw material powders shown in Examples 24 to 29 and Reference Examples 1 to 10, respectively, and wet-mixed by a ball mill to prepare a ceramic slurry. . These ceramic slurries were molded into a sheet shape by the doctor blade method so that the thickness of the dielectric ceramic layer after baking became 2 m, thereby obtaining a rectangular ceramic green sheet. Subsequently, the conductive paste containing Ni as an electroconductive powder was screen-printed on these ceramic green sheets, and the electrically conductive paste layer for forming an internal electrode was formed. The ceramic green sheet in which the conductive paste layer was formed was laminated in plural sheets so that the side from which the conductive paste was drawn was different from each other to obtain a green laminate. This green laminate was heated to 350 ℃ in a nitrogen gas atmosphere, then the combustion of a binder, in 1250 ℃ in a reducing atmosphere consisting of 10 ^-10.5 MPa oxygen partial pressure of H ₂ gas, N ₂ gas and H ₂ O gases It baked for 2 hours and obtained the ceramic laminated body.

Cu paste containing glass frit is applied to both end surfaces of the ceramic laminate after firing, and the Cu paste is baked at a temperature of 700 ° C. in an N ₂ atmosphere to form an external electrode electrically connected to the internal electrode. The multilayer ceramic capacitors of Examples 24 to 29 and Reference Examples 1 to 10 made of the dielectric ceramic composition of the invention were obtained.

The external dimensions of the multilayer ceramic capacitors (Examples 24 to 29 and Reference Examples 1 to 10) thus obtained were 1.2 mm in width, 2.0 mm in length, and 1.2 mm in thickness, respectively, and were interposed between internal electrodes. The thickness of the layer was 2.0 mu m. The total number of effective dielectric ceramic layers was 300, and the area of the counter electrode per layer was 1.0 mm 2.

(5) Characterization of multilayer ceramic capacitors

For each of the multilayer ceramic capacitors of Examples 24 to 29 and Reference Examples 1 to 10, the dielectric constant?, The temperature characteristic, the high temperature load life, and the third harmonic distortion factor THD were measured as in Examples 16 to 23, respectively. The results are shown in Table 5. In addition, the arbitrary fracture surface containing the center part of a multilayer ceramic capacitor was analyzed similarly to each said Example, the ceramic structure was analyzed, the composition of the secondary particle was confirmed, and the result is shown in Table 5. In Table 5, a represents the value of Zr / (Zr + Ti + Hf).

a b c d e total Gd (b × 4) total Mg (b + e) ε Temperature characteristic 125 ℃ /% High temperature load test THD / dB Example 24 0.40 2.0 2.0 0.5 0.5 8.0 2.5 530 -13.7 0/100 -80 Example 25 0.06 1.0 2.0 0.5 1.0 4.0 2.0 1790 -14.8 0/100 -70 Example 26 0.06 10.0 6.0 0.5 0.5 40.0 10.5 360 -14.7 0/100 -81 Example 27 0.06 2.0 2.0 0.5 18.0 8.0 20.0 630 -11.3 0/100 -74 Example 28 0.06 2.0 15.0 0.5 0.5 8.0 2.5 1070 -21.4 0/100 -75 Example 29 0.06 2.0 2.0 5.0 0.5 8.0 2.5 1270 -17.0 0/100 -72 Reference Example 1 0.02 2.0 2.0 0.5 0.5 8.0 2.5 1960 -29.2 0/100 -63 Reference Example 2 0.95 2.0 2.0 0.5 0.5 8.0 2.5 40 -4.5 0/100 -108 Reference Example 3 0.06 0.5 2.0 0.5 2.0 2.0 2.5 2400 -12.9 0/100 -60 Reference Example 4 0.06 20.0 10.0 0.5 0.0 80.0 20.0 160 -32.0 0/100 -88 Reference Example 5 0.06 1.0 2.0 0.5 0.0 4.0 1.0 2210 -12.8 0/100 -61 Reference Example 6 0.06 2.0 2.0 0.5 38.0 8.0 40.0 230 -25.3 0/100 -83 Reference Example 7 0.06 2.0 0.5 0.5 0.5 8.0 2.5 1230 -13.8 0/100 -62 Reference Example 8 0.06 2.0 30.0 0.5 0.5 8.0 2.5 850 -32.8 0/100 -79 Reference Example 9 0.06 2.0 2.0 0.1 0.5 8.0 2.5 1320 -15.9 1/100 -72 Reference Example 10 0.06 2.0 2.0 15.0 0.5 8.0 2.5 1130 -23.3 4/100 -74

According to the result shown in Table 5, it turned out that it is the following.

That is, as shown in Examples 24 to 29, a (= Zr / (Zr + Ti + Hf)) satisfies the condition of 0.06 to 0.40, and the content (= 4 × b) of the rare earth element R to ABO ₃ is 4 to When 40 mol%, content (= b + e) of Mg is 2-20 mol%, and content c of Si is 2-15 mol%, the characteristic especially excellent in temperature characteristic, high temperature load reliability, etc. was obtained. However, as shown in Reference Examples 1 to 10, when the substitution ratio of Zr and the content of each of the rare earth elements R, Mg and Si are outside the scope of the present invention, the characteristics deteriorate and decrease slightly as described later. Since there exist secondary particle which consists of complex oxide which has an element R and Mg as a main component, it has the outstanding characteristic, respectively compared with the conventional.

As shown in Reference Example 1, when a was less than 0.06, the temperature characteristics deteriorated slightly due to the increase in the Curie point. As shown in Reference Example 2, when a exceeded 0.40, the dielectric constant? Decreased. As shown in Reference Example 3, when the content (= 4 × b) of the rare earth element R is less than 4 mol%, the phase dissolved by the rare earth element R in the columnar particles decreases, so that the THD deteriorates, As shown in Reference Example 4, when the content exceeded 40 mol%, the phase in which the rare earth element R was dissolved in the columnar particles increased, so that the dielectric constant? Decreased and the temperature characteristics slightly decreased. As shown in Reference Example 5, when the content of Mg (= b + e) is less than 2 mol%, the phase of solid solution of Mg in the columnar particles decreases, so that THD deteriorates, and when it exceeds 20 mol% as shown in Reference Example 6 Since the solid solution phase of Mg in the columnar particles increases, the temperature characteristic deteriorates slightly. As shown in Reference Example 7, when the content c of Si is less than 2 mol%, the sintering property is lowered and the THD deteriorates. As shown in Reference Example 8, when it exceeds 15 mol%, oversintering occurs, and the temperature characteristic deteriorates slightly. It was. In addition, as shown in Reference Examples 9 and 10, even if the content d of MnO ₂ was less than 0.5 mol% or more than 5 mol%, the high temperature load reliability slightly decreased.

In addition, this invention is not restrict | limited to the said Example at all, and is included in this invention, unless it contradicts the meaning of this invention.

The present invention can be suitably used for a multilayer ceramic capacitor.

Claims (7)

ABO ₃ (where A site contains Ba or Ba and at least one of Ca and Sr, and B site represents a perovskite crystal including Ti or Ti and at least one of Zr and Hf). ) Main phase particles with the main component, rare earth element R (where R is Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu In the dielectric ceramic composition comprising Mg and Si, there are secondary particles composed of a crystalline complex oxide containing the rare earth elements R and Mg as main components. Moreover, when a part of Ti of said B site is substituted by Zr, the relationship of 0.06 <= Zr / (Zr + Ti + Hf) <= 0.40 in molar conversion is established, and also, Content of the rare earth elements R, Mg, and Si to ABO ₃ is, in terms of moles, the rare earth elements R: 4 to 40%, Mg: 2 to 20%, and Si: 2 to 15%, respectively. Dielectric ceramic composition. 2. The dielectric ceramic composition according to claim 1, wherein the crystalline composite oxide mainly composed of the rare earth elements R and Si is substantially absent. The dielectric ceramic composition according to claim 1 or 2, wherein there are columnar particles in which the rare earth elements R and Mg are dissolved in solid solution, and further comprising a crystalline composite oxide containing Mg and Si as a main component. The metal element M according to claim 1 or 2, wherein the ABO ₃ is 0.5 mol% or more and 5 mol% or less (wherein M is Cr, V, Mn, Fe, Co, Ni, Cu, Nb, At least one of Mo and W.). The dielectric ceramic composition according to claim 1 or 2, comprising a sintering aid comprising Si and at least one of Ca, Ba, B and Li. ABO ₃ (where A site contains Ba or Ba and at least one of Ca and Sr, and B site represents a perovskite crystal including Ti or Ti and at least one of Zr and Hf). ) And at least one rare earth element R (wherein R is Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu). And a step of preparing a reactant having a crystallinity in part, a step of preparing a raw material powder by mixing at least the ABO ₃ and the reactant, and a step of firing the raw material powder. A method for producing a dielectric ceramic composition, characterized in that. A plurality of laminated dielectric ceramic layers, a plurality of internal electrodes formed along a specific interface between the dielectric ceramic layers so as to obtain capacitance, and external electrodes electrically connected to specific ones of the internal electrodes; A multilayer ceramic capacitor, wherein the dielectric ceramic layer is formed of the dielectric ceramic composition according to claim 1 or 2.

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