JP2954298B2 - Dielectric porcelain composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [FIELD OF THE INVENTION The present _{invention, Ba kx M x O k ·} TiO 2 ( where, M is predetermined element, k and x predetermined value) as the basic component, porcelain The present invention relates to a dielectric ceramic composition suitable as a dielectric for a capacitor.

[Prior _{Art] Ba kx M x O k ·} TiO 2 ( where, M is predetermined element, k and x
Examples of the dielectric porcelain composition having a basic component of (a predetermined numerical value) include, for example,
There is one disclosed in Japanese Patent Publication No. 60-118667.

JP-A-60-118667 discloses a dielectric porcelain composition comprising Ba _kx M _x O _k TiO ₂ (where M is Mg, Zn, S
r and at least one metal of Ca, k is a number in the range from 1.0 to 1.04, x is a number in the range from 0.02 to 0.05)
Parts by weight of basic components, B ₂ O ₃ , SiO ₂ and MO (where MO is BaO,
MgO, ZnO, is obtained by firing an additive component of 0.2 to 10.0 parts by weight consisting of at least one metal oxide) of SrO and CaO, a mixture of, and with the B ₂ O ₃ and SiO ₂ In a triangular diagram in which the composition range with MO indicates these compositions in mol%, the first B ₂ O ₃ is 15 mol%, the SiO ₂ is 25 mol%, and the MO is 60 mol%. A second point B having a composition of 30 mol% of the B ₂ O _3, 1 mol% of the SiO _{2, and} 69 mol% of the MO, and 90 mol% of the B ₂ O ₃ ; A third point C having a composition of 1 mol% of SiO _{2 and} 6 mol% of MO, 89 mol% of B ₂ O ₃ ,
A fourth point D indicating a composition in which the SiO ₂ is 10 mol% and the MO is 1 mol%, and the B ₂ O ₃ is 24 mol%, the SiO ₂ is 75 mol%, and the MO is 1 mol% The fifth point E indicating the composition is in a region surrounded by five straight lines that sequentially connect the fifth point E.

This dielectric porcelain composition can be used in a non-oxidizing atmosphere.
Since it can be obtained by sintering at a relatively low temperature of 00 ° C. or less, a base metal such as nickel can be used as an internal electrode, and a ceramic capacitor can be manufactured at low cost together with the saving of heat energy. It is an excellent thing.

The dielectric ceramic composition has a non-dielectric constant 率_s of 2000.
As described above, the dielectric loss tan δ is 2.5% or less and the resistivity ρ is 1 × 10
^It has electrical characteristics of ⁶ MΩcm or more, and
Capacitance temperature change rate Tc is ± 10% in the temperature range of + 85 ° C
It is possible to obtain a porcelain capacitor having excellent characteristics within (B in JIS).

[Problems to be Solved by the Invention] With the progress of miniaturization and high integration of electronic devices and the like, electronic components such as porcelain capacitors are also required to be reduced in size and increased in capacity.

One way to reduce the size and increase the capacitance of a ceramic capacitor is to reduce the thickness of the dielectric layer.However, if the dielectric layer is too thin, its DC breakdown voltage will decrease. As a result, dielectric breakdown occurs, and the reliability of the withstand voltage cannot be maintained.

For this reason, there is a CR product as an index of how thin the dielectric layer can be. This CR product is the capacitance C
And the insulation resistance R. If the dielectric layer is thinned to cause dielectric breakdown, the value becomes small.
If the dielectric breakdown does not occur even if the thickness of the dielectric layer is reduced, the value increases.

Therefore, as the dielectric ceramic composition used for the dielectric layer of the ceramic capacitor, it is desirable that the value of this CR product is as large as possible.

However, the above-mentioned conventional dielectric porcelain composition has firing conditions,
Dielectric constant ε _s , tan δ, resistivity ρ, temperature change rate T of capacitance
Although c was excellent, the CR product was at most about 400 MΩ · μF.

An object of the present invention, non-1250 ° C. in an oxidizing atmosphere at temperatures below can be sintered, dielectric constant epsilon _s is 2800 or higher, the dielectric loss tanδ is less 2.5%, C · R product is 40
To provide a dielectric porcelain composition capable of obtaining a porcelain capacitor having a capacitance temperature change rate of ± 10% or less (B in JIS) in a temperature range of −25 ° C. to + 85 ° C. in a temperature range of 0 MΩ · μF or more. It is in.

[Means for Solving the Problems] The dielectric porcelain composition according to the present invention comprises Ba _kx M _x O _k TiO
₂ (However, M is Sr and / or Ca, k is 1.00 to 1.04, x
Is from 0.01 to 0.05), B ₂ O ₃ , SiO ₂ and MO
(Where MO is one or more oxides selected from BaO, MgO, SrO and CaO) and Cr ₂ O
₃ and a mixture of a second additive component consisting of MnO and a sintered product, wherein the first additive component and the second additive component are the basic component 10
In a ternary diagram in which the composition range of the first additive component is represented by mol% of the composition ratio of B ₂ O ₃ , SiO ₂ and MO with respect to 0 part by weight, ₂ O ₃ is 1 mol%,
Point A indicating a composition of 39 mol% of SiO _{2 and} 60 mol% of MO, and B ₂
Point B indicating a composition of 25 mol% of O ₃ , 25 mol% of SiO _{2 and} 50 mol% of MO, 39 mol% of B ₂ O ₃ , 60 mol% of SiO _{2 and} 1 mol of MO
A point C indicating a composition of mol%, B ₂ O ₃ was 4 mol%, and SiO ₂ was 95%
A point D representing a composition of 1 mol% of MO and 1 mol% of MO, and a point E representing a composition of 1 mol% of B ₂ O _3, 95 mol% of SiO _{2 and} 4 mol% of MO.
And MnO is 5 to 100 parts by weight of the first additive component.
40 parts by weight, wherein the Cr ₂ O ₃ is contained in an amount of 10 to 30 parts by weight based on 100 parts by weight of the first additive component.

Here, the value of k in the composition formula of the basic component is from 1.00 to
The reason for setting the range of 1.04 is that when the value of k is in the range of 1.00 to 1.04, a sintered body having desired electrical characteristics can be obtained. Is 2.5
% Or more, the CR product is less than 400, and k
If the value exceeds 1.04, a dense sintered body cannot be obtained by firing at a temperature of 1250 ° C.

Further, the value of x, which is the ratio of the element of the M component in the composition formula of the basic component, is set to the range of 0.01 to 0.05, because the desired electrical characteristic is obtained when the value of x is in the range of 0.01 to 0.05. When the value of x is less than 0.01, the temperature change rate Tc of the capacitance exceeds ± 10%, and when the value of x exceeds 0.05, This is because the temperature change rate Tc of the capacitance exceeds ± 10%.

Sr and Ca of the M component are both Group II metals,
It works almost the same, and the same effect can be obtained by using either or both at the same time.

In addition, a trace amount of a mineralizer may be added to the added components as long as the object of the present invention is not impaired, and the sinterability may be improved.Other substances may be added as necessary. You may.

Further, as a starting material for obtaining the basic component, other than those shown in Examples described later, for example, oxides such as BaO, SrO, CaO, hydroxides, carbonates or other compounds may be used. Good.

In addition, the first additive component and the second additive component are the basic component 100
0.2 to 10.0 parts by weight with respect to parts by weight means that the first additive component and the second additive component are contained in a ratio of 0.2 to 10.0 parts by weight with respect to 100 parts by weight of the basic component. 1
A dense sintered body having desired electrical properties can be obtained by firing at 250 ° C., but the first additive component and the second additive component are less than 0.2 parts by weight based on 100 parts by weight of the basic component. Cannot obtain a dense sintered body by firing at a temperature of 1250 ° C., and the first additive component and the second additive component
If it exceeds 10.0 parts by weight, relative dielectric constant ε _s
Is less than 2800, tan δ is 2.5% or more, and the CR product is less than 400.

Further, in the ternary diagram showing the composition range of the first additive component in terms of the composition ratio of B ₂ O ₃ , SiO ₂ and MO in mol%, the point A
The point E is set in the region surrounded by five straight lines connecting in this order, as long as the composition range of the first additive component falls within this region, a sintered body having desired electrical characteristics can be obtained. However, if the composition range of the first additive component is outside this range, a dense sintered body cannot be obtained by firing at a temperature of 1250 ° C., or the CR product is less than 400. Or tanδ is
This is because it becomes 2.5% or more.

The MO components BaO, MgO, SrO and CaO work almost in the same way, and any one of them may be used or an appropriate ratio may be used.

Further, it is assumed that MnO is contained at a ratio of 5 to 40 parts by weight with respect to 100 parts by weight of the first additive component, because the ratio of MnO is 5 to 40 parts by weight with respect to 100 parts by weight of the first additive component. If it is included, a dense sintered body having desired electrical characteristics can be obtained by firing at 1250 ° C., but MnO is the first additive component 100.
If the amount is less than 5 parts by weight with respect to parts by weight, a dense sintered body cannot be obtained by firing at a temperature of 1250 ° C.,
MnO is if it exceeds 40 parts by weight with respect to the first additive component 100 parts by weight, since the dielectric constant epsilon _s is less than 2800.

Further, Cr ₂ O ₃ is 10 to 30 parts by weight based on 100 parts by weight of the first additive component.
The reason that it is contained in the proportion of parts by weight is that if Cr ₂ O ₃ is contained in the proportion of 10 to 30 parts by weight with respect to 100 parts by weight of the first additive component, the desired firing at 1250 ° C. Although it is possible to obtain a dense sintered body having electrical properties, when Cr ₂ O ₃ is less than 10 parts by weight based on 100 parts by weight of the first additive component,
CR product is less than 400, and Cr ₂ O ₃ is the first added component
If it exceeds 30 parts by weight per 100 parts by weight, the dielectric constant epsilon _s is from less than 2800.

As starting materials for obtaining the additional components, oxides, hydroxides, carbonates, or other compounds other than those shown in Examples described later may be used.

Example First, the case of Sample No. 1 in Table 1 will be described.

Preparation of Basic Components The compounds of Formula 1 (purity of 99.0% or more) were weighed, and these compounds were put into a pot mill together with a plurality of alumina balls and 2.5 of water, followed by stirring and mixing for 15 hours to obtain a mixture.

Here, the weight of the compound of formulation 1 (g), as a composition formula Ba _kx M _x O _k TiO ₂ in the basic component, the _{Ba 1.00 Sr 0.01 Ca 0.01 O 1.02} TiO 2 ... (1), the impurity Is a value calculated in consideration of.

Next, the mixture was placed in a stainless steel pot, dried at 150 ° C. for 4 hours using a hot air drier, and the dried mixture was coarsely pulverized. Calcination was performed at 2 ° C. for 2 hours to obtain a powder of a basic component having a composition represented by the composition formula (1).

Preparation of Additive Component Also, a first additive component consisting of the compound shown in Formulation 2;
A second additive component comprising the compound shown in Formulation 3 was weighed, added to a polyethylene pot together with a plurality of aluminum balls and 300 ml of alcohol, and stirred and mixed for 10 hours to obtain a mixture.

Here, the weight (g) of each compound in Formulation 2 is 7% for B ₂ O _3.
This is a value calculated to have a composition of mole parts, 49 mole parts of SiO _{2 and} 44 mole parts of CaCO ₃ .

The weight (g) of each compound in Formulation 3 was B ₂ O ₃ , SiO ₂ ,
To first additive component consisting of CaCO _3, MnO is 25 parts by weight, Cr
_This is a value calculated such that ₂ O ₃ has a composition of 20 parts by weight.

Next, the mixture was calcined in the atmosphere at a temperature of about 1000 ° C. for 2 hours, and this was put into an alumina pot together with a plurality of alumina balls and 300 ml of water, and ground for 15 hours.
Thereafter, the mixture was dried at 150 ° C. for 4 hours to obtain a powder of the additive having the above composition.

Preparation of Slurry Next, 100 parts by weight (1000 g) of the basic component and 1.0 part by weight (10 g) of the additional component are put in a ball mill, and further, 15 weight% of the total weight of the basic component and the additional component is added. %
Was added, and 50% by weight of water was added, and these were mixed and pulverized to obtain a slurry as a raw material of the dielectric ceramic composition.

Here, as the organic binder, one composed of an aqueous solution of an acrylate polymer, glycerin and a condensed phosphate was used.

Formation of unsintered porcelain sheet Next, the slurry was subjected to a defoaming process by placing it in a vacuum defoaming machine, and the defoamed slurry was applied on a polyester film at a predetermined thickness using a reverse roll coater, The applied slurry was heated to 100 ° C. and dried to obtain a long unsintered porcelain sheet having a thickness of about 25 μm. Then, the long unsintered porcelain sheet was cut to obtain a 10 cm square unsintered porcelain sheet.

Preparation and printing of conductive paste In addition, 10 g of nickel powder having an average particle size of 1.5 μm and 0.9 g of ethyl cellulose dissolved in 9.1 g of butyl carbitol were placed in a stirrer, and stirred for 10 hours to obtain a conductive paste. Was.

Then, 50 patterns (length: 14 mm, width: 7 mm) of this conductive paste were formed on one surface of the unsintered porcelain sheet by a screen printing method and dried.

Lamination of unsintered porcelain sheets Next, two unsintered porcelain sheets were laminated with the side on which the pattern made of the conductive paste was formed facing upward. During the lamination, the pattern made of the conductive paste was shifted by about half in the longitudinal direction between the adjacent upper and lower unsintered porcelain sheets.

Then, four unsintered porcelain sheets each having a thickness of 60 μm were laminated on both the upper and lower surfaces of the laminate to obtain a laminate.

Crimping and cutting of the laminate Next, at a temperature of about 50 ° C., a pressure of about 40 tons is applied in a thickness direction of the laminate, and a plurality of unsintered porcelain sheets constituting the laminate are formed. Were pressed together. Then, the laminate was cut into a lattice to obtain 50 laminate chips.

Firing of the laminated chip Next, the laminated chip is placed in a furnace capable of firing in an atmosphere, the inside of the furnace is set to the atmospheric atmosphere, and the temperature is 600 ° C at a rate of 100 ° C / h.
The organic binder in the unsintered porcelain sheet was burned.

After that, the atmosphere in the furnace was changed from an air atmosphere to a reducing atmosphere {H ₂ (2% by volume) + N ₂ (98% by volume)}, and the temperature in the furnace was changed from 600 ° C. to a sintering temperature of 1250 ° C. at 100 ° C./h. Temperature, hold at this temperature for 3 hours, then lower the temperature to 600 ° C at a rate of 100 ° C / h, change the atmosphere in the furnace to an air atmosphere (oxidizing atmosphere), and raise the temperature at 600 ° C. The oxidation treatment was performed by holding for 30 minutes, and then cooled to room temperature to obtain a laminated sintered body chip.

Formation of External Electrodes Next, a pair of external electrodes is formed on the end faces of the laminated sintered body chips where the ends of the internal electrodes are exposed, as shown in FIG. Layer of dielectric porcelain layer
10, 10, 10; two layers of internal electrodes 12, 12; and a pair of external electrodes 1
As a result, a laminated ceramic capacitor 10 composed of Nos. 4 and 14 was obtained.

Here, a conductive paste composed of zinc, glass frit and a vehicle is applied to the end surface of the external electrode 14, and after drying the conductive paste, the conductive paste is heated to a temperature of 550 ° C. in the air. For 15 minutes to form a zinc electrode layer 16, a copper layer 18 is further formed on the zinc electrode layer 16 by electroless plating, and a Pb-Sn solder layer 20 is further formed on the copper layer 18 by electroplating. Formed.

The thickness of the dielectric ceramic layer 10 of this multilayer ceramic capacitor is 0.02 mm, and the facing area of the pair of internal electrodes 12 and 12 is 5 mm × 5 m.
m = 25 mm ² . The composition of the dielectric ceramic layer 10 after sintering is substantially the same as the composition of the mixture of the basic components and the additional components before sintering.

Next, using this laminated ceramic capacitor, the relative dielectric constant ε
_{When s} , tan δ and CR product were determined, as shown in Table 1, the relative dielectric constant ε _s was 3050, tan δ was 1.6%, and the CR product was 580 MΩ · μF.

The temperature characteristics of the capacitance of the laminated ceramic capacitor were determined in the range of -25 ° C to + 85 ° C, as shown in FIG. 2, and the rate of change ΔC based on the capacitance of + 20 ° C
_-25 and ΔC _{+ 85} are, as shown in Table 1, ΔC- ₂₅ is −8.1%,
ΔC ₊₈₅ was + 3.9%.

Here, the temperature characteristics of the relative permittivity ε _s , tan δ, C · R product, and capacitance were obtained in the following manner.

(A) The relative dielectric constant ε _s is as follows: temperature 20 ° C., frequency 1 kHz, voltage 0.
The capacitance was measured under the condition of 5 V (effective value), and the capacitance was calculated from this measured value, the facing area of the internal electrode of 25 mm ² and the thickness of the dielectric ceramic layer between the internal electrodes of 0.02 mm.

(B) a dielectric loss tan [delta (%) was determined by the relative permittivity epsilon _s the same conditions.

(C) The CR product is obtained by measuring the insulation resistance (MΩ) by applying 50 V DC for 1 minute at a temperature of 20 ° C., and calculating from the product of the insulation resistance (MΩ) and the capacitance (μF). Was.

(D) The temperature characteristics of the capacitance are as follows: put a laminated ceramic capacitor in a thermostat, -25 ° C, 0 ° C, + 20 ° C, + 40 ° C, + 60 ° C.
At each temperature of ℃ and + 85 ℃, frequency 1kHz, voltage 0.5V
The capacitance was measured under the condition of (effective value), and the rate of change at each temperature with respect to the capacitance at 20 ° C. was obtained.

As described above, the sample of No. 1 was described, but the samples of No. 2 to 30 were the same as the sample of No. 1 except that the compositions of the basic components and the added components were changed as shown in the left column of Table 1. A laminated ceramic capacitor was prepared by exactly the same method, and the electrical characteristics were measured by the same method. The electrical characteristics of the samples of Nos. 2 to 30 were as shown in the right column of Table 1.

In Table 1, k-x, x, k in the column of basic component
Is the ratio of the number of atoms of each element in the composition formula of the basic component, that is,
The ratio of the number of atoms of each element when the number of atoms of Ti is 1 is shown.

As is evident from Table 1, the sample according to the present invention can be sintered by firing at a temperature of 1250 ° C. or less,
The relative dielectric constant ε _s is 2800 or more, the dielectric loss tan δ is 2.5% or less, the CR product is 400 MΩ · μF or more, and the temperature change rate Tc of the capacitance is within ± 10% from -25 ° C to + 85 ° C (B ).

In contrast, the samples of Nos. 4, 6, 9, 10, 12, 15, 18 to 24, 29, and 30 do not have the desired electrical characteristics. Therefore, these No. samples are outside the scope of the present invention.

Next, the reasons for limiting the composition range of the dielectric ceramic composition according to the present invention will be described with reference to the results shown in Table 1.

First, the value of k in the composition formula of the basic component will be described.

As shown in Sample No. 8, when the value of k is 1.00, a sintered body having desired electrical characteristics can be obtained.
As shown in sample No. 24, in the case of 0.98, tan δ is 6.6%,
The CR product becomes 50. Therefore, the lower limit of k is 1.
It is 0.

When the value of k is 1.04, as shown in Sample No. 7, a sintered body having desired electrical characteristics can be obtained.
As shown in Sample No. 21, in the case of 1.05, a dense sintered body cannot be obtained at a temperature of 1250 ° C. Therefore, the upper limit of k is 1.04.

Next, the value of x in the composition formula of the basic component will be described.

As shown in sample No. 3, when the value of x is 0.01, a sintered body having desired electrical characteristics can be obtained.
As shown in Sample No. 22, when the value is zero, the temperature change rate Tc of the capacitance exceeds ± 10%. Therefore, the lower limit of x is 0.01.

Further, when the value of x is 0.05 as shown in Sample No. 5, a sintered body having desired electrical characteristics can be obtained, but as shown in Sample No. 23, it is 0.06. In this case, the temperature change rate Tc of the capacitance exceeds ± 10%. Therefore, x
Has an upper limit of 0.05.

 Next, the amount of the additional component will be described.

As shown in Sample No. 11, when the amount of the added component is 0.2 parts by weight with respect to 100 parts by weight of the basic component, 1250 ° C.
A dense sintered body can be obtained by firing
As shown in FIG. 9, when the temperature is zero, a dense sintered body cannot be obtained at 1250 ° C. Therefore, the lower limit of the amount of the added component is 0.2 parts by weight based on 100 parts by weight of the basic component.

In addition, as shown in Sample No. 13, when the added amount of the additive component was 10.0 parts by weight with respect to 100 parts by weight of the basic component, a sintered body having desired electrical characteristics could be obtained. But,
As shown in Sample No. 20, in the case of 12 parts by weight, the relative dielectric constant ε _s was 2630, tan δ was 2.7%, and the CR product was 350.
Therefore, the lower limit of the amount of the added component is 10.0 parts by weight based on 100 parts by weight of the basic component.

Next, a preferable composition range of the additive component will be described with reference to a ternary diagram showing the composition ratio of B ₂ O ₃ —SiO ₂ —MO in FIG.

In this ternary diagram, Samples No. 2, 3, 14, 16, 17 located at the boundary of the present invention range connecting points A to E in this order and Sample Nos. 1, 5, located within the present invention range 7,8,11,13,25,26,27,28
According to the method, a sintered body having desired electrical characteristics could be obtained.

On the other hand, in this ternary diagram, according to Sample Nos. 4, 6, 10, 15, and 30 located outside the range of the present invention, whether a dense sintered body cannot be obtained at a temperature of 1250 ° C. CR product is 400
Or tan δ has risen to 2.5% or more.

Therefore, the composition of the additive component is B ₂ O ₃ —SiO ₂ —MO in FIG.
In the ternary diagram showing the composition ratio of B ₂ O ₃ , 1 mol%, SiO ₂
There 39 mol%, and the point A shows the composition MO is 60 mol%, B ₂ O ₃
A point B indicating a composition of 25 mol%, 25 mol% of SiO _{2 and} 50 mol% of MO, and a point B indicating a composition of 39 mol% of B ₂ O _3, 60 mol% of SiO _{2 and} 1 mol% of MO C, a point D indicating a composition of 4 mol% of B ₂ O _3, 95 mol% of SiO ₂ , and 1 mol% of MO; 1 mol% of B ₂ O ₃ , 95 mol% of SiO ₂ , and MO A range surrounded by five straight lines connecting the point E showing the composition of 4 mol% in this order is preferable.

Further, it is understood that Mo may be at least one of BaO, MgO, SrO, and CaO.

 Next, the amount of MnO added will be described.

As shown in Sample No. 27, a dense sintered body could be obtained when the addition amount of MnO was 5 parts by weight with respect to 100 parts by weight of the added component, as shown in Sample No. 9. As described above, in the case of zero, a dense sintered body could not be obtained at a temperature of 1250 ° C. Therefore, the lower limit of the added amount of MnO is 5 parts by weight for 100 parts by weight of the added component.

Further, as shown in Sample No. 28, the amount of MnO added was 100%.
In the case of 40 parts by weight with respect to parts by weight of the added components, a sintered body having desired electrical characteristics could be obtained, but Sample No. 1
As shown in FIG. 2, in the case of 45 parts by weight, the relative dielectric constant ε is 2560.
And less than 2800. Therefore, the upper limit of the amount of MnO added is 40 parts by weight for 100 parts by weight of the added components.

Next, the amount of Cr ₂ O ₃ added will be described.

As shown in sample No. 25, when the added amount of Cr ₂ O ₃ is 10 parts by weight with respect to 100 parts by weight of the added component, a sintered body having desired electric characteristics can be obtained. As shown in Sample No. 19, when 5 parts by weight is added to 100 parts by weight of the added components, the CR product is less than 370 and 400. Therefore, Cr ₂ O
The upper limit of the added amount of ₃ is 10 per 100 parts by weight of the added component.
Parts by weight.

Further, as shown in Sample No. 26, the amount of Cr ₂ O ₃ added was 10
In the case of 30 parts by weight with respect to 0 parts by weight of the added component, a sintered body having desired electrical characteristics can be obtained.
As shown in No. 18, in the case of 35 parts by weight, the relative dielectric constant ε _s
But less than 2660 and 2800.

In the above embodiment, the laminated chip is sintered in a reducing atmosphere, but may be sintered in a neutral atmosphere such as N ₂ or Ar.

In the above embodiment, the heat treatment temperature of the laminated body chip in the oxidizing atmosphere was set to 600 ° C., but the heat treatment temperature may be lower than the sintering temperature, and is 500 to 1000 ° C.
Can be performed in the range of What kind of temperature needs to be variously changed in consideration of the oxidation of the electrode material (eg, nickel) and the oxidation of the dielectric ceramic composition.

[Effects of the Invention] According to the present invention, a ceramic capacitor having a CR product of 400 MΩ · μF or more can be obtained. Therefore, the size and the capacity of the ceramic capacitor can be reduced while maintaining a required withstand voltage. Is what you can do.

Moreover, according to the present invention, the dielectric porcelain composition is heated to 1250 ° C.
As it can be densely sintered by firing at the following temperature, heat energy for firing can be saved,
An inexpensive base metal such as nickel can be used as the metal of the internal electrode of the porcelain capacitor, so that the production cost of the porcelain capacitor can be reduced.

Further, according to the present invention, the relative dielectric constant ε _{s of the} dielectric porcelain composition is 2800 or more and the dielectric loss tan δ is 2.5% or less, so that a ceramic capacitor having required electric characteristics can be obtained. It is.

Furthermore, according to the present invention, the temperature change rate of the capacitance is −25.
It is possible to obtain a porcelain capacitor within ± 10% at ℃ to + 85 ° C, that is, satisfying the B characteristic of JIS standard.

[Brief description of the drawings]

1 is a cross-sectional view of a ceramic capacitor according to an embodiment of the present invention, FIG. 2 is a temperature characteristic diagram of the capacitance of the ceramic capacitor of Sample No. 1, and FIG. 3 shows a composition range of the first additive component. It is a ternary diagram. 10: dielectric ceramic layer, 12: internal electrode 14: external electrode, 16: zinc electrode layer 18: copper layer 20: Pb-Sn solder layer

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C04B 35/42-35/49 H01B 3/00-3/14 CA (STN) REGISTRY (STN)

Claims (1)

(57) [Claims] 1. A _{Ba kx M x O k TiO 2} ( where, M is Sr and / or Ca, k is 1.00 to 1.04, x is 0.01 to 0.05) and the basic component consisting, a B ₂ O ₃ and SiO ₂ MO (where MO is BaO, MgO, SrO and C
a first additive component composed of one or more oxides selected from aO) and a mixture of a second additive component composed of Cr ₂ O ₃ and MnO, which is obtained by sintering; Component and the second additive component, the basic component 100
Contained in a proportion of 0.2 to 10.0 parts by weight relative to the weight part, the composition range of the first additive component, in the ternary diagram showing the composition ratio of B ₂ O ₃ and SiO ₂ and MO in a molar%, B ₂ O ₃ is 1 mol%, Si
Point A indicating a composition of O ₂ of 39 mol% and MO of 60 mol%, and B ₂ O ₃
B indicates a composition of 25 mol%, SiO ₂ of 25 mol%, and MO of 50 mol%, and B indicates a composition of 39 mol% of B ₂ O _3, 60 mol% of SiO _{2 and} 1 mol% of MO. Point C, point D indicating a composition of 4 mol% of B ₂ O _3, 95 mol% of SiO _{2 and} 1 mol% of MO, and 1 mol% of B ₂ O ₃ , 95 mol% of SiO ₂ and MO Is in a region surrounded by five straight lines connecting a point E indicating a composition of 4 mol% with the MnO in an amount of 5 to 40 with respect to 100 parts by weight of the first additive component.
A dielectric porcelain composition, wherein the Cr ₂ O ₃ is contained in an amount of 10 to 30 parts by weight with respect to 100 parts by weight of the first additive component.