JP2009096671A - Dielectric ceramic and multi-layer ceramic capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a strontium titanate-based multi-layer ceramic capacitor which has high-temperature accelerated life property comparable to or higher than that of a barium titanate-based multi-layer ceramic capacitor, and has temperature characteristic showing X5R characteristic. <P>SOLUTION: A dielectric ceramic is provided containing SrTiO<SB>3</SB>as a principal phase and containing 0.2-5.0 moles of an Mg component, 0.1-1.0 mole of a metal element selected from among Mn and V, 0.3-5.0 moles of an Re component (Re is one or more metals selected from among Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y), and 0.15-10 moles of SiO<SB>2</SB>or an Si-containing glass component, based on 100 moles of SrTiO<SB>3</SB>, and ceramic particles constituting the dielectric ceramic have a core-shell structure. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a dielectric ceramic, a manufacturing method thereof, and a multilayer capacitor using the dielectric ceramic.

  The multilayer ceramic capacitor has a ceramic multilayer body composed of a plurality of dielectric ceramic layers and a plurality of internal electrodes formed so as to be alternately drawn to different end faces through the dielectric ceramic layers. The external electrodes are formed on both end faces of the ceramic laminate so as to be electrically connected to the internal electrodes.

As dielectric ceramics used for such a multilayer ceramic capacitor, there are mainly barium titanate (BaTiO ₃ ) -based materials. Since barium titanate-based dielectric ceramics have a high dielectric constant, a small-sized and large-capacity multilayer ceramic capacitor can be formed. However, barium titanate-based dielectric ceramics have piezoelectricity. Therefore, when a voltage is applied, the multilayer ceramic capacitor expands and contracts in the thickness direction or the length direction, causing displacement. The direction of this displacement changes depending on the direction of the applied voltage. For example, under conditions where the voltage changes periodically, such as an input capacitor of a CPU of a personal computer or an image processing circuit of a liquid crystal display or a plasma display, the direction of displacement also changes so as to vibrate continuously. This continuous change in the direction of displacement causes so-called noise.

In order to reduce the displacement of the multilayer ceramic capacitor that causes noise, strontium titanate (SrTiO ₃ ) -based material is used as the dielectric ceramic. Strontium titanate has a lower strain rate than barium titanate-based materials as disclosed in, for example, Japanese Patent Application Laid-Open Nos. 2004-292173 and 2000-264729. Therefore, by using the strontium titanate material, it is possible to reduce the displacement of the multilayer ceramic capacitor that causes noise.

JP 2004-292173 A JP 2000-264729 A

However, dielectric ceramics using strontium titanate-based materials have a Curie point on the low temperature side (−60 ° C. or lower), so that the temperature change of the dielectric constant in the normal temperature region is large, and dielectrics using barium titanate-based materials. It was difficult to obtain a monolithic ceramic capacitor having temperature characteristics of R characteristics (temperature change rate within ± 15%) compared to body ceramics. Further, regarding the high temperature accelerated life characteristics, it was difficult for the strontium titanate multilayer ceramic capacitor to obtain the same characteristics as the barium titanate multilayer ceramic capacitor.

The present invention has a high temperature accelerated life characteristic equivalent to that of a barium titanate-based multilayer ceramic capacitor, and the temperature characteristic exhibits an X5R characteristic (within ± 15% within a temperature range of −55 ° C. to + 85 ° C. on a 25 ° C. basis). A strontium titanate multilayer ceramic capacitor can be obtained.

In the present invention, as a first solving means, SrTiO ₃ is the main phase, Mg component is added to 100 mol of SrTiO ₃ , 0.2 to 5.0 mol in terms of MgO, and a metal element selected from Mn and V 0.1 to 1.0 mol in terms of oxide containing one atom of metal element, Re component (Re is selected from Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y 1 type or 2 or more types of metal elements), 0.3 to 5.0 mol in terms of oxide in which one molecule of metal element is contained in one molecule, and a glass component containing SiO ₂ or Si in an amount of 0.002 in terms of SiO ₂ . Proposed is a dielectric ceramic containing 15 to 10 mol of dielectric ceramic, wherein the ceramic particles constituting the dielectric ceramic have a core-shell structure.

Further, in the present invention, as a second solution, a multilayer ceramic having a plurality of dielectric ceramic layers, an internal electrode formed between the dielectric ceramic layers, and an external electrode electrically connected to the internal electrode In the capacitor, a multilayer ceramic capacitor is proposed in which the above dielectric ceramic is used as the dielectric ceramic layer, and the internal electrode is made of Ni or Ni alloy.

According to the first and second solving means, the strontium titanate-based multilayer ceramic capacitor uses a dielectric ceramic composed of ceramic particles having a core-shell structure, whereby a barium titanate-based multilayer ceramic capacitor and It is possible to obtain equivalent high-temperature life characteristics. In addition, strontium titanate-based dielectric ceramics have a core-shell structure for the ceramic particles that form them, so that the temperature characteristics of the core strontium titanate crystals and the solid solution of strontium titanate that forms the shell These temperature characteristics and the temperature characteristics are combined to obtain an R characteristic temperature characteristic.

According to the present invention, it is possible to obtain a strontium titanate-based multilayer ceramic capacitor having high temperature accelerated life characteristics equivalent to those of a barium titanate-based multilayer ceramic capacitor and having temperature characteristics of X5R characteristics.

An embodiment according to a dielectric ceramic of the present invention will be described. The dielectric ceramic of the present invention has SrTiO ₃ + Mg component + M component + Re component + Si component (Re component is one or two selected from Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y) species more metal elements, M component metal element selected from Mn and V, Si component is represented by the glass component) containing SiO ₂ or Si.

SrTiO ₃ is synthesized by mixing SrCO ₃ and TiO ₂ and heat-treating at 1200 ° C. to 1300 ° C. Conventional SrTiO ₃ was synthesized by heat treatment at 1000 ° C. or lower. Therefore, the crystallinity is low and it is difficult to form a core-shell structure. However, since SrTiO _{3 which} is the main phase of the dielectric ceramic of the present invention is heat-treated at a relatively high temperature of 1200 ° C. to 1300 ° C., it has high crystallinity and can easily form a core-shell structure. In order to give the dielectric ceramics reduction resistance, the Sr / Ti ratio is preferably 0.95 to 1.05.

Mg component is 0.2-5.0 mol with respect to 100 mol of SrTiO ₃ . In this case, the number of moles of the Mg component is specified in terms of MgO. When the Mg component is less than 0.2 mol or more than 5.0 mol, the sinterability of the dielectric ceramic is lowered. As the Mg component, MgO is usually used.

The M component is a metal element selected from Mn and V, and is 0.1 to 1.0 mol with respect to 100 mol of SrTiO ₃ . In this case, the M component is specified in terms of mol in terms of an oxide in which one molecule of a metal element is contained in one molecule. Here, “as an oxide equivalent in which one element of a metal element is contained in one molecule” means converting to an oxide having one metal atom in one molecule. For example, if V ₂ O ₅ is VO, Converted as _5/2 . When the M component is less than 0.1 mol or more than 1.0 mol, the sinterability of the dielectric ceramic is lowered. As a raw material for the M component, V ₂ O ₅ is used in the case of V. In the case of Mn, MnCO ₃ , Mn ₃ O ₄ or the like is used in addition to MnO.

The Re component is one or more rare earth metal elements selected from Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y, and is one for each 100 mol of SrTiO _3. It is 0.3 mol to 5.0 mol in terms of oxide in which one atom of a metal element is contained in the molecule. When the Re component is less than 0.3 mol or more than 5.0 mol, the sinterability of the dielectric ceramic is lowered. As a raw material for the Re component, respective trivalent oxides, that is, oxides represented by Re ₂ O ₃ are used.

The Si component is a glass component containing SiO ₂ or Si, and is 0.15 mol to 10 mol in terms of SiO _{2 with} respect to 100 mol of SrTiO ₃ . When the Si component is less than 0.15 mol, the dielectric ceramic is not densified. On the other hand, when the Si component is more than 10 mol, the ceramic particles grow and the temperature characteristics deviate from the range of the R characteristics. Examples of the raw material for the Si component include glass components such as Li—Si glass and B—Si glass in addition to SiO ₂ . In addition, in the case of such a glass component, the addition amount is specified by the number of moles of Si.

Further, a metal element selected from Cr, Fe, Co, Ni, Cu, Mo and W may be added in an amount of about 0.1 mol in terms of an oxide containing one atom of metal element per molecule.

The dielectric ceramic of the present invention is composed of ceramic particles having the above-described composition and having a core-shell structure as shown in FIG. The ceramic particle 8 shown in FIG. 2 has a core 9 made of a pure strontium titanate crystal phase and a shell 10 made of a solid solution phase of strontium titanate and an additive component such as Mg. Since the ceramic particles 8 have a core-shell structure, grain growth is suppressed. Therefore, the dielectric ceramic of the present invention has more grain boundary parts with high insulation resistance compared to the conventional strontium titanate dielectric ceramics formed of solid solution particles that are easy to grow, and barium titanate. High temperature life characteristics equivalent to dielectric ceramics can be obtained.

  The core 9 of the ceramic particles 8 shows the temperature characteristics of pure strontium titanate crystals, and the shell 10 shows the temperature characteristics of the solid solution of strontium titanate. The temperature characteristic of the entire ceramic particle 8 is a temperature characteristic obtained by synthesizing the temperature characteristic of the core 9 and the temperature characteristic of the shell 10. By synthesizing different temperature characteristics, the ceramic particles 8 can obtain flat temperature characteristics. As a result, the dielectric ceramic of the present invention can have temperature characteristics of X5R characteristics.

Next, a multilayer ceramic capacitor according to an embodiment of the present invention will be described. As shown in FIG. 1, the multilayer ceramic capacitor 1 according to the present embodiment includes a dielectric ceramic 3 and internal electrodes 4 formed so as to face each other through the dielectric ceramic 3 and be alternately drawn to different end faces. The outer electrode 5 is formed on both end surfaces of the ceramic laminate 2 so as to be electrically connected to the inner electrode. On the external electrode 5, a first plating layer 6 for protecting the external electrode 5 and a second plating layer 7 for improving the solder wettability are formed as necessary.

  The dielectric ceramic 3 is formed of the dielectric ceramic of the present invention. Therefore, in the multilayer ceramic capacitor 1 of the present invention, the dielectric ceramic 3 is composed of strontium titanate ceramic particles having a core-shell structure, has temperature characteristics of X5R characteristics, and has a barium titanate dielectric ceramic. Has the same high temperature life characteristics. In addition, since strontium titanate is a paraelectric material, the multilayer ceramic capacitor 1 of the present invention has a lower distortion rate than a multilayer ceramic capacitor using a barium titanate dielectric ceramic, and causes multilayer noise. The expansion and contraction of the capacitor is reduced.

The internal electrode 4 is made of Ni or a Ni alloy such as a Ni—Cu alloy. Since Ni or Ni alloy has a melting point higher than the sintering temperature (1100 ° C. to 1400 ° C.) of the dielectric ceramic, it can be fired simultaneously with the firing of the dielectric ceramic. Further, since it is cheaper than Pd or the like, a large-capacity multilayer ceramic capacitor having a large number of internal electrodes can be obtained at low cost.

The external electrode 5 is electrically connected to the internal electrode 4. The external electrode 5 is fired simultaneously with the firing of the dielectric ceramics using a paste such as Ni whose melting point is higher than the sintering temperature of the dielectric ceramics, or after the ceramic laminate 2 is sintered, Ag paste or Cu paste is used. It is formed by a method such as baking. A first plating layer 6 for protecting the external electrode 5 is formed on the external electrode 5, and a second plating layer 7 is further formed on the first plating layer 6. The first plating layer 6 is made of a metal such as Ni or Cu, and the second plating layer is made of a metal having good soldering properties such as Sn or Sn alloy.

  Next, a method for manufacturing the dielectric ceramic and the multilayer ceramic capacitor of the present invention will be described. In the following description of the process, the described composition ratio will be described as the composition ratio when the sintered body is formed. The blending is performed, for example, in an amount taking into account the amount of ions eluted by wet mixing and the amount of evaporation during firing, and blended so that a sintered body is formed at the described composition ratio.

First, SrCO ₃ and TiO ₂ are prepared so that Sr: Ti is in a molar ratio of 95: 100 to 105: 100. Water is added to the prepared SrCO ₃ and TiO ₂ and wet-mixed for about 15 to 24 hours using a ball mill, bead mill, dispa mill or the like. The obtained mixture is dried and subjected to heat treatment at 1200 ° C. to 1300 ° C. for about 2 hours to synthesize strontium titanate.

On the other hand, with respect to 100 mol of SrTiO ₃ , MgO is 0.2 to 5.0 mol, M component is MnO or V ₂ O ₅ (VO _5/2 conversion) is 0.1 to 1.0 mol, and Re component is, for example, Ho _2. O ₃ is mixed in an amount of 0.3 to 5.0 mol in terms of HoO _3/2 , and, for example, SiO ₂ is mixed as a Si component at a ratio of 0.15 to 10 mol, water is added, and a ball mill, a bead mill, a dispar mill, etc. are used For about 15 to 24 hours. Thereafter, drying is performed to obtain an additive material.

Next, the synthesized strontium titanate and the additive material are mixed, water is added, and wet mixing is performed for about 15 to 24 hours using a ball mill, a bead mill, a dispa mill or the like. The mixture is then dried and calcined at 1000 ° C. In this way, a dielectric ceramic composition is obtained.

The obtained dielectric ceramic composition is mixed with a butyral or acrylic organic binder, a solvent and other additives to form a ceramic slurry. This ceramic slurry is formed into a sheet using a coating device such as a roll coater, and a ceramic green sheet having a predetermined thickness to be the dielectric ceramic layer 3 is formed. On this ceramic green sheet, a conductive layer of Ni or Ni alloy is applied in a predetermined pattern shape by screen printing to form a conductor layer that becomes the internal electrode 4.

After stacking the required number of ceramic green sheets on which the conductor layers are formed, they are pressure bonded to form a raw laminate. After this is cut and divided into individual chips, the binder is removed in the air or in a non-oxidizing gas such as nitrogen. After debinding, a conductive paste is applied to the exposed surface of the internal electrode of the individual chip to form a conductive film that becomes the external electrode 5. The individual chip on which the conductor film is formed is fired in a nitrogen-hydrogen atmosphere at a predetermined temperature (oxygen partial pressure of about 10 ⁻¹⁰ atm). The external electrode 5 may be baked by applying a conductive paste containing glass frit to the exposed surface of the internal electrode after firing the individual chip to form the ceramic laminate 2. The external electrode 5 can use the same metal as the internal electrode, and can also use Ag, Pd, AgPd, Cu, Cu alloy, or the like. Further, the first plated layer 6 made of Ni, Cu or the like is formed on the external electrode 5, and the second plated layer 7 made of Sn or Sn alloy or the like is formed thereon, whereby the multilayer ceramic capacitor 1 is obtained.

(Synthesis of main phase)
Main phase A: As starting materials, SrCO ₃ was prepared by weighing it to a ratio of 101 mol and TiO ₂ of 100 mol. Next, the prepared starting materials were wet mixed in a ball mill for 15 hours, dried and then heat-treated at 1300 ° C. for 2 hours to obtain a main phase A powder.

Main phase B: As starting materials, SrCO ₃ was prepared by weighing out at a ratio of 101 mol and TiO ₂ at a ratio of 100 mol. Next, the prepared starting materials were wet mixed in a ball mill for 15 hours, dried, and heat-treated at 1000 ° C. for 2 hours to obtain a main phase B powder.

Main phase C: 101 mol of SrCO ₃ , 100 mol of TiO ₂ , 2.0 mol of MgO, 0.4 mol of MnO, and 3.0 mol of Yb ₂ O ₃ in terms of YbO _3/2 as starting materials Each was prepared by weighing. Next, the prepared starting materials were wet mixed in a ball mill for 15 hours, dried, and then heat-treated at 1000 ° C. for 2 hours to obtain main phase C powder. The compositions of the main phases A, B and C are shown in Table 1.

Example 1
As shown in Table 2, with respect to 100 mol of the main phase A, MgO is 2.0 mol, MnO is 0.4 mol, Yb ₂ O ₃ is 3.0 mol in terms of YbO _3/2 , and SiO ₂ is 1.5 mol. Each was prepared by weighing. The prepared MgO, MnO, Yb ₂ O ₃ and SiO ₂ were mixed, water was added, and wet mixing was performed for about 15 to 24 hours using a ball mill to obtain an additive material. The obtained additive material and the main phase A were mixed, water was added, and wet-mixed for about 15 to 24 hours using a ball mill. The mixture was then dried and calcined at 1000 ° C. to obtain a dielectric ceramic composition powder.

To the above powder, polyvinyl butyral, an organic solvent, and a plasticizer were added and mixed to form a ceramic slurry. This ceramic slurry was made into a sheet by a roll coater to obtain a ceramic green sheet having a thickness of 7 μm. Ni internal electrode paste was applied on the ceramic green sheet by screen printing to form an internal electrode pattern. 11 ceramic green sheets on which internal electrode patterns are formed are stacked, and ceramic green sheets on which no internal electrode patterns are formed are stacked on top and bottom of the ceramic green sheets, and pressure-bonded by 4.0 × 2.0 × 1.0 mm. The raw chip was formed by cutting and dividing into pieces. This raw chip was debindered in a nitrogen atmosphere, coated with a Ni external electrode paste, and fired in a reducing atmosphere (nitrogen-hydrogen atmosphere, oxygen partial pressure 10 ⁻¹⁰ atm) at 1330 ° C. for 1 hour. Thereafter, the temperature was lowered to room temperature at a temperature decrease rate of 750 ° C./hr. In this way, a multilayer ceramic capacitor of Sample 1 having a size of 3.2 × 1.6 × 0.8 mm was obtained. Further, as Sample 2, the subsequent steps were performed in the same manner as in Sample 1 using main phase B. In this way, a multilayer ceramic capacitor of Sample 2 was obtained.

Also, using the main phase C, main phase C and the main phase C100mol were weighed so that the SiO ₂ in the ratio of 1.5mol mixed respect, 15-24 hour or so wet by using a ball mill with the addition of water Mixed. The mixture was then dried and calcined at 1000 ° C. to obtain a dielectric ceramic composition powder. Using the dielectric ceramic composition powder, the subsequent steps were performed in the same manner as in the case of Sample 1 to obtain a multilayer ceramic capacitor of Sample 3.

  With respect to the obtained multilayer ceramic capacitor having a size of 3.2 × 1.6 × 0.8 mm and a dielectric ceramic layer of 4 μm, measurement of dielectric constant (ε), tan δ, temperature characteristics and high-temperature life characteristics, and core-shell structure The presence or absence was observed. For the dielectric constant, ten multilayer ceramic capacitors as samples were prepared, and their respective capacitances were measured with an LCR meter 4284A manufactured by Hewlett-Packard Company. The measured values and the internal electrode of the multilayer ceramic capacitor as a sample were measured. The average value of 10 samples was calculated from the intersection area, the dielectric ceramic layer thickness, and the number of laminated layers. tan δ was measured with an LCR meter 4284A manufactured by Hewlett-Packard Co., and the measured value for 10 samples was obtained and used as the average value.

Regarding the temperature characteristics, the capacitance was sampled at intervals of 5 ° C. in the range of −55 ° C. to + 85 ° C. for each of 10 samples, and ± 10% from the capacitance when all 10 samples were at 25 ° C. If it was within, it was rated as ○. Regarding the high-temperature life characteristics, the acceleration conditions were set to 150 ° C. and 70 V for each sample, the leakage current was monitored, and it was broken when the current flowed 500 nA or more. Formula log (average life) −50 × log (EXP (1)) × (0.25−1 / layer thickness)
The life level was calculated with Those having a life level of 4 or more were accepted as a life level equivalent to that of a barium titanate-based multilayer ceramic capacitor.

  The presence or absence of the core-shell structure was observed for each sample with a TEM (transmission electron microscope). These results are shown in Table 3.

  From the above results, if the dielectric ceramic and the multilayer ceramic capacitor using the main phase A, the temperature characteristics are X5R characteristics, and the high-temperature accelerated lifetime characteristics are equivalent to those of the barium titanate-based multilayer ceramic capacitors. I understood it. In the dielectric ceramics using the main phase A, ceramic particles having a core-shell structure were observed.

(Example 2)
A dielectric ceramic powder was formed in the same manner as in Example 1 of the present invention in Example 1 so that a sintered body having the composition shown in Table 4 was obtained. Here, the effect was verified by changing the amount and type of Mg added.

  A multilayer ceramic capacitor was formed from the above dielectric ceramic powder in the same manner as in Example 1. The dielectric constant, tan δ, temperature characteristics and high-temperature life characteristics were measured, and the presence or absence of a core-shell structure was observed.

  From the above results, if the Mg range is 0.2 to 5.0 mol, the temperature characteristics are X5R characteristics, and the high-temperature accelerated lifetime characteristics are the same as those of barium titanate-based multilayer ceramic capacitors. I understood it.

(Example 3)
A dielectric ceramic powder was formed in the same manner as in Example 1 so that a sintered body having the composition shown in Table 6 was obtained. Here, the effect was verified by changing the amount of Mn or V added.

  A multilayer ceramic capacitor was formed from the above dielectric ceramic powder in the same manner as in Example 1. The dielectric constant, tan δ, temperature characteristics and high-temperature life characteristics were measured, and the presence or absence of a core-shell structure was observed.

  From the above results, if the range of Mn or V is in the range of 0.1 to 1.0 mol, the temperature characteristics are X5R characteristics, and the high temperature accelerated life characteristics are the same life level as the barium titanate-based multilayer ceramic capacitor. I found out that It was also found that Mn and V may be mixed within the scope of the present invention.

Example 4
A dielectric ceramic powder was formed in the same manner as in Example 1 so that a sintered body having the composition shown in Table 8 was obtained. Here, the effect was verified by changing the addition amount and type of rare earth components.

  A multilayer ceramic capacitor was formed from the above dielectric ceramic powder in the same manner as in Example 1. The dielectric constant, tan δ, temperature characteristics and high temperature life characteristics were measured, and the presence or absence of a core-shell structure was observed.

  From the above results, if the range of the rare earth component is in the range of 0.3 to 5.0 mol, the temperature characteristics are X5R characteristics, and the high temperature accelerated life characteristics are at the same life level as the barium titanate multilayer ceramic capacitor. I found out. From the results of Sample 24, it was found that when a rare earth component (La) other than that defined in the present invention was used, the solid solution state changed and a core-shell structure was not formed. Further, it was found that the effects of the present invention can be obtained with the rare earth component defined by the present invention.

(Example 5)
A dielectric ceramic powder was formed in the same manner as in Example 1 so that a sintered body having the composition shown in Table 10 was obtained. Here, the effect was verified by changing the addition amount of SiO ₂ .

  A multilayer ceramic capacitor was formed from the above dielectric ceramic powder in the same manner as in Example 1. The dielectric constant, tan δ, temperature characteristics and high-temperature life characteristics were measured, and the presence or absence of a core-shell structure was observed.

From the above results, if the SiO ₂ range is in the range of 0.15 to 10 mol, the temperature characteristic is the X5R characteristic, and the high temperature accelerated life characteristic is the same life level as the barium titanate-based multilayer ceramic capacitor. I understood. In addition, when the addition amount of SiO ₂ is small, as shown in the sample 27, densification is not performed, and when the addition amount of SiO ₂ is large, the core-shell structure is not formed as shown in the sample 28, and desired temperature characteristics are obtained. And it was found that the life characteristics could not be obtained.

(Example 6)
A dielectric ceramic powder was formed in the same manner as in Example 1 so that a sintered body having the composition shown in Table 12 was obtained. Here, a metal element selected from Cr, Fe, Co, Ni, Cu, Mo, and W was added to the composition of Sample 1, and the effect was verified.

A multilayer ceramic capacitor was formed from the above dielectric ceramic powder in the same manner as in Example 1. The dielectric constant, tan δ, temperature characteristics and high-temperature life characteristics were measured, and the presence or absence of the core-shell structure was observed.

  From the above results, even when a metal element selected from Cr, Fe, Co, Ni, Cu, Mo and W is further added, the temperature characteristics are X5R characteristics, and the high temperature accelerated life characteristics are barium titanate-based multilayer ceramics. It was found that the lifetime was equivalent to the capacitor.

It is the figure which represented the cross section of the multilayer ceramic capacitor typically. It is a schematic diagram which shows the ceramic particle which has a core-shell structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Multilayer ceramic capacitor 2 Ceramic multilayer body 3 Dielectric ceramics 4 Internal electrode 5 External electrode 6 1st plating layer 7 2nd plating layer 8 Ceramic particle 9 Core 10 Shell

Claims (2)

SrTiO ₃ as the main phase,
Mg component is 0.2-5.0 mol in terms of MgO with respect to 100 mol of SrTiO _3.
A metal element selected from Mn and V is 0.1 to 1.0 mol in terms of oxide containing one atom of metal element in one molecule.
Re component (Re is one or more metal elements selected from Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y), and one molecule contains one atom of metal element 0.3-5.0 mol in terms of oxide
The glass component containing SiO ₂ or Si is 0.15 to 10 mol in terms of SiO ₂
Dielectric ceramics containing at a ratio of
Ceramic particles constituting the dielectric ceramic have a core-shell structure.
Dielectric ceramics characterized by that. In a multilayer ceramic capacitor having a plurality of dielectric ceramic layers, internal electrodes formed between the dielectric ceramic layers, and external electrodes electrically connected to the internal electrodes,
The dielectric ceramic layer has SrTiO ₃ as a main phase,
Mg component is 0.2-5.0 mol in terms of MgO with respect to 100 mol of SrTiO _3.
A metal element selected from Mn and V is 0.1 to 1.0 mol in terms of oxide containing one atom of metal element in one molecule.
Re component (Re is one or more metal elements selected from Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y), and one molecule contains one atom of metal element 0.3-5.0 mol in terms of oxide
The glass component containing SiO ₂ or Si is 0.15 to 10 mol in terms of SiO ₂
Is a dielectric ceramic containing at a ratio of
A multilayer ceramic capacitor characterized in that the ceramic particles constituting the dielectric ceramic have a core-shell structure, and the internal electrodes are formed of Ni or Ni alloy.

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