JPH08151260A - Dielectric porcelain composition - Google Patents

Abstract

PURPOSE: To provide the dielectric porcelain composition having relative permittivity of >=2500, a sintering temperature of <=1300 deg.C, an electrostatic capacity temperature change rate satisfying the X7R of the EIA standard, a small dielectric loss of <=2.5%, and an insulating resistance of >=10<4> MΩ, and little in electric voltage dependency. CONSTITUTION: The dielectric porcelain composition comprises 100 pts.wt. of BaTiO3 , 0.8-2.5 pts.wt. of Nb2 O5 , 0.06-0.70 pt.wt. of MgO, 0.005-0.520 pt.wt. of Pr6 O11 or Gd2 O3 , 0.01-0.30 pt.wt. (converted into MnCO3 ) of MnO, and preferably further 0.05-0.50 pt.wt. of at least one of SiO2 and Al2 O3 and <=0.5 pt.wt. of ZnO, wherein the Nb2 O5 /MgO molar ratio is 0.5-2.2.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a BaTiO ₃ as a main component, to a _{Nb 2 O 5, MgO, MnO} , dielectric ceramic composition containing a Pr ₆ O ₁₁ or Gd ₂ O _3.

[0002]

2. Description of the Related Art Conventionally, dielectric ceramic compositions have been used as materials for laminated ceramic capacitors and the like. Such a monolithic ceramic capacitor is constructed by laminating a plurality of green sheets of a dielectric ceramic composition having internal electrodes so as to have a predetermined capacity, and then integrally firing them. For example, X7R (EIA standard: temperature characteristic of capacitance is -55
The dielectric ceramic composition used for the laminated ceramic capacitor of +/- 15 ° C at + 25 ° C
It is important that the relative dielectric constant is as high as 2500 or more, the thickness of each green sheet is 15 μm or less, and the firing temperature is 1300 ° C. or less.

That is, the relative dielectric constant at 25 ° C. is 2500
As described above, by setting the thickness of the green sheet to 15 μm or less, the thickness of the green sheet between the internal electrodes and the facing area can be minimized, and the multilayer ceramic capacitor can be downsized. Further, by setting the firing temperature to 1300 ° C. or lower, the selection range of the material of the internal electrodes is increased, and for example,
It is possible to use inexpensive Pd-Ag from expensive 100% Pd material. In addition to the above, the dielectric loss tan δ and the insulation resistance, which are various characteristics of the dielectric ceramic composition, must be fully taken into consideration, and it is further desired that the dielectric loss has a small AC voltage dependency.

Conventionally, as a device having an improved relative dielectric constant,
A dielectric ceramic composition containing BaTiO ₃ , Nb ₂ O ₅ , and ZnO has already been proposed (Japanese Patent Laid-Open No. 59-18162).
JP, JP-A-59-18159, etc.). Such a dielectric ceramic composition has a relative dielectric constant of 2000.
Can be up to 3000. However, even though the above-mentioned dielectric ceramic composition can obtain a high relative permittivity, the dielectric loss tan δ is large, so that the green sheet cannot be thinned, and when used in a multilayer capacitor, a high relative dielectric constant is eventually obtained. Dielectric constant could not be obtained.

As a system developed to reduce the dielectric loss tan δ in this way, BaTiO ₃ , Nb is used.
A dielectric ceramic composition containing ₂ O ₅ , MgO, and La ₂ O ₃ has already been proposed (see Japanese Patent Publication No. 5-10766). In addition, Nb ₂ O ₅ and MgO are mixed so that the molar ratio of Nb ₂ O ₅ / MgO to BaTiO ₃ is in the range of 2.3 to 4.
And a rare earth element is added thereto in an amount of 0.1 to 0.5% by weight (see Japanese Patent Publication No. 55-19007).

[0006]

However, none of the above-mentioned dielectric ceramics has a small relative permittivity of about 2200 or less and cannot cope with a reduction in size and capacity. Further, there is a problem that the dielectric loss is still large and it is difficult to make the green sheet thin.

Furthermore, in any of the above-mentioned dielectric ceramics, it is considered that the AC loss dependency of the dielectric loss becomes large and it becomes impossible to cope with the thinning of the dielectric material.
In this case, there is a problem that it is not possible to cope with the miniaturization and the large capacity of the capacitor.

[0008]

[Means for Solving the Problems] As a result of intensive studies made by the present inventors in view of the above problems, barium titanate BaT
iO ₃ as a main component, Nb ₂ O ₅ , MgO, Pr ₆ O ₁₁
Alternatively, it contains Gd ₂ O ₃ and MnO in a predetermined composition ratio, and the molar ratio of Nb ₂ O ₅ to MgO is 0.5 to
By setting 2.2, the relative dielectric constant is 2500 or more,
The temperature change rate of capacitance satisfies X7R of EIA standard,
Dielectric loss is as small as 2.5% or less, and AC voltage is 2000
The inventors have found that a dielectric porcelain having a small dielectric loss of 3.0% or less even when a voltage of V / cm is applied and having a small AC voltage dependence and capable of being thinned can be obtained, and completed the present invention.

That is, the dielectric ceramic of the present invention is made of BaTiO 3.
₃ Nb ₂ O ₅ 0.8 to 2.5 with respect to 100 parts by weight
Parts by weight, 0.06 to 0.70 parts by weight of MgO, Pr ₆ O
₁₁ or Gd ₂ O ₃ 0.005~0.520 parts,
MnO is contained in an amount of 0.01 to 0.30 parts by weight in terms of MnCO ₃ , and the molar ratio of Nb ₂ O ₅ to MgO is 0.5 to 2.2. In addition, BaTiO ₃ 100
With respect to parts by weight, at least SiO ₂ , Al ₂ O
It is desirable to contain 0.05 to 0.50 parts by weight of any one of ₃ and 0.5 parts by weight or less of ZnO.

In the present invention, 0.80 to 2.5 parts by weight of Nb ₂ O ₅ is contained with respect to 100 parts by weight of BaTiO ₃ because the dielectric loss is deteriorated when the content is less than 0.80 parts by weight. This is because the temperature characteristics and sinterability are poor, and when the amount exceeds 2.5 parts by weight, the relative dielectric constant decreases and the temperature characteristics deteriorate significantly. Nb ₂ O ₅ is preferably contained in an amount of 1.3 to 2.0 parts by weight based on 100 parts by weight of BaTiO ₃ .

Further, MgO is set to 0.06 to 0.70 parts by weight because when it is less than 0.06 parts by weight, the relative dielectric constant and the insulation resistance are lowered, the temperature characteristics are deteriorated, grain growth is caused, and the voltage of dielectric loss. This is because the dependency becomes large. Also, 0.7
This is because if the amount is more than 0 parts by weight, the dielectric constant decreases and the insulation resistance also decreases. MgO is preferably 0.1 to 0.4 parts by weight.

Further, the amount of Pr ₆ O ₁₁ or Gd ₂ O ₃ being 0.005 to 0.520 parts by weight means that Pr ₆ O ₁₁
Alternatively, if Gd ₂ O ₃ is less than 0.005 parts by weight, the relative dielectric constant is lowered and the sinterability is poor, and if it exceeds 0.520 parts by weight, the temperature characteristics are deteriorated. Pr ₆ O ₁₁ or G
It is desirable that d ₂ O ₃ is 0.005 to 0.2 part by weight.

Further, MnO is converted to MnCO ₃ in an amount of 0.01 to
The amount of 0.30 parts by weight is less than 0.01 parts by weight, the insulation resistance decreases, the dielectric loss and the sinterability deteriorate, and
This is because if the amount exceeds 0 parts by weight, the relative dielectric constant decreases. MnO is preferably 0.04 to 0.10 parts by weight in terms of MnCO ₃ .

The molar ratio of Nb ₂ O ₅ to MgO is set to 0.5 to 2.2. When the molar ratio is smaller than 0.5, the relative dielectric constant is deteriorated and the temperature characteristics and sinterability are improved. If it is worse than 2.2, the temperature characteristics are poor and the relative dielectric constant is lowered. In the present invention, the molar ratio of Nb ₂ O ₅ to MgO is particularly preferably set to 0.6 to 1.4.

Further, 0.05 to 0.50 parts by weight of at least one of SiO ₂ and Al ₂ O ₃ is added to 100 parts by weight of BaTiO ₃ , and the content is 0.0
This is because when the amount is less than 5 parts by weight, the effect of improving the relative permittivity, the effect of improving the sinterability, and the effect of improving the voltage dependency are hardly obtained, and when the amount is more than 0.50 part by weight, the relative permittivity decreases. This is because they tend to SiO ₂ and Al ₂ O ₃
At least one of them is preferably contained in an amount of 0.1 to 0.2 parts by weight based on 100 parts by weight of BaTiO ₃ .

Furthermore, it is desirable that the amount of ZnO be 0.5 parts by weight or less with respect to 100 parts by weight of BaTiO ₃ , but this is because when ZnO is more than 0.5 parts by weight, the temperature characteristics are poor and the dielectric properties are low. This is because the loss tends to increase. ZnO is added to 100 parts by weight of BaTiO ₃ .
It is preferably 3 parts by weight or less.

The BaTiO ₃ used in the present invention is, for example, an average crystal grain size of 1.0 μm produced by any one of the solid phase method, sol-gel method, oxalic acid method, hydrothermal synthesis method and the like.
Based on the following BaTiO ₃ powder as a main component, this BaTi
Nb ₂ O ₅ , MgO, Pr for 100 parts by weight of O _3
6 O ₁₁ or Gd ₂ O ₃ , MnCO ₃ , SiO ₂ , Al
_A predetermined amount of each of ₂ O ₃ and ZnO powder is weighed, wet-milled for 20 to 48 hours by a ball mill or the like, dried, and then a predetermined amount of a binder is added to form a predetermined shape, which is then heated to 1230 ° C. in the atmosphere. It is manufactured by firing at 1300 ° C. for 1 to 2 hours. In the case of producing a monolithic ceramic capacitor, the above powder is slurried, formed into a sheet by a doctor blade method, and an internal electrode such as Ag-Pd is appropriately applied to the sheet-shaped formed body, and these are formed. It suffices to stack a plurality of sheets and perform simultaneous firing under the above firing conditions.

Nb ₂ O ₅ , MgO, used in the present invention
Pr ₆ O ₁₁ or Gd ₂ O ₃ , MnCO ₃ , SiO ₂ ,
Instead of Al ₂ O ₃ and ZnO powders, Nb, Mg, P
It is also possible to use hydroxides, carbonates, nitrates, oxalates, alkoxides, etc. of r or Gd, Mn, Si, Al, Zn, which decompose into oxides at a temperature below the sintering temperature.

To improve the AC voltage dependency, it is preferable to control the average crystal grain size d of the sintered body to d <1.0 μm. In this way, the average crystal grain size d of the sintered body is d <1.
To control the particle size to 0 μm, barium titanate powder having an average crystal grain size of 1.0 μm or less is used as a starting material, or the grain size after pulverization is controlled to 0.8 μm or less by wet pulverization for a long time. Should be set as low as possible and the firing time should be short.

[0020]

In the dielectric ceramic composition of the present invention, the temperature characteristic of capacitance is within ± 15% in the range of -55 ° C to 125 ° C, the relative dielectric constant at + 25 ° C is 2500 or more, and the thickness of the green sheet is Is 15 μm, the dielectric loss is as small as 2.5% or less, and the dielectric loss at an AC voltage of 2000 V / cm can be as small as 3% or less. Therefore, a small-sized and large-capacity multilayer capacitor can be obtained.

Further, since the firing temperature is 1300 ° C. or less, it is easy to manufacture industrially, and the internal electrode is inexpensive silver-palladium (Ag / Pd = 20 / 80-40 / 60).
A dielectric porcelain that can be used for a multilayer capacitor using the is achieved. Furthermore, the dielectric loss, which is the basic characteristics of a dielectric ceramic, is 2.5% or less, and the insulation resistance (IR) is 1
A sufficiently satisfactory dielectric porcelain of 0 ⁴ MΩ or more is achieved.

[0022]

EXAMPLES Examples of the present invention will be described in detail below.

Average particle size produced by the oxalic acid method
Based on BaTiO ₃ powder of 0 μm or less as the main component,
100 parts by weight of aTiO ₃ , Nb ₂ O ₅ , Mg
O, Pr ₆ O ₁₁ , MnCO ₃ , SiO ₂ , Al ₂ O ₃ ,
Each powder of ZnO was weighed as shown in Table 1, wet-milled for 20 to 48 hours in a ball mill, and then an organic binder was added thereto, followed by stirring and a doctor blade method to obtain a thickness of 15 μm.
m was formed into a tape shape. This tape is 130mm x 1
It is cut into 00 mm and 20 sheets are piled up to produce a laminated body.

[0024]

[Table 1]

As the internal electrodes, Ag-Pd type paste (Ag / Pd = 30/70) was printed. This laminated body was cut into 3.2 mm × 1.6 mm, and was cut in air 123
Baking was performed at 0 to 1330 ° C. for 2 hours. Further, electrodes made of silver paste were baked on both end faces at 800 ° C. for 10 minutes to prepare a measurement sample.

The capacitance and the dielectric loss of such a sample were measured at a reference temperature of 25 ° C., a frequency of 1.0 kHz and a measurement voltage of 1.0 Vrms. The temperature change rate of the capacity was measured in the range of −55 to + 125 ° C., and the capacity at + 25 ° C. was used as a reference. Further, the insulation resistance was measured when a DC voltage of 25 V was applied for 1 minute. The relative permittivity was calculated back from the capacitance. The average particle size of the sintered body was calculated by observing the surface of the sintered body at a magnification of 15,000 with a scanning electron microscope and measuring 500 or more particles by the line intercept method. Furthermore, 2000 Vrms / c at a frequency of 1 kHz
The dielectric loss when a voltage of m was applied was measured. Table 2 shows the above results.

[0027]

[Table 2]

Any of the dielectric ceramics within the scope of the present invention has a large relative permittivity of 2500 or more, and moreover, it has an EIA standard of X.
7R characteristics (capacity change rate within ± 15% in the temperature range of −55 ° C. to 125 ° C.) are satisfied. Furthermore, the dielectric loss tan
δ is as small as 2.5% or less, AC voltage 2000 Vrms
A loss of 3.0% or less is shown even under / cm. Further, the insulation resistance (IR) is 10 ⁴ MΩ or more.

In Table 1, sample numbers 1 to 5 are Nb ₂ added to BaTiO ₃ which is the main component of the dielectric ceramic composition.
The amount of O ₅ added was varied from 0.7 to 2.6 parts by weight. At this time, MgO, Pr ₆ O ₁₁ , and MnCO ₃
Were added to 0.2 parts by weight, 0.2 parts by weight, and 0.1 parts by weight.

Sample No. 1 (addition amount of Nb ₂ O ₅ : 0.7
In parts by weight), the relative dielectric constant εr is 3460, which is a good product, but the dielectric loss tan δ is 3.3%. Further, the temperature characteristic becomes -25%. Further, in the sample numbers 2 to 4 (addition amount of Nb ₂ O ₅ : 0.8 to 2.5 parts by weight), the relative dielectric constant εr becomes 2670 to 3640,
Dielectric loss tan δ is less than 2.4% and temperature characteristics are ±
Within 14%, tan δ when an AC voltage of 2000 V / cm is applied is 2.8% or less, and the insulation resistance (IR) is 5 to 9
The range is × 10 ⁴ MΩ, which is a good product. That is, the relative permittivity εr
High, excellent temperature characteristics, small dielectric loss tan δ,
Further, a dielectric ceramic having a small dielectric loss AC voltage dependency is achieved. Further, Sample No. 5 (addition amount of Nb ₂ O ₅ :
(2.6 parts by weight), the relative permittivity ε is 2290 and the temperature characteristics are deteriorated to -20%. Therefore, in the present invention, Nb ₂ O ₅ added to barium titanate BaTiO ₃ is used.
The weight was set to a range of 0.8 to 2.5 parts by weight with respect to 100 parts by weight of barium titanate BaTiO ₃ .

In Sample Nos. 6 to 10, the addition amount of MgO added to BaTiO ₃ which is the main component of the dielectric ceramic composition was changed to 0.05 to 0.75 parts by weight. At this time, the amount of Nb ₂ O ₅ added is 0.8 to 2.5 parts by weight, P
The amounts of r ₆ O ₁₁ and MnCO ₃ added were 0.2 parts by weight and 0.1 parts by weight, respectively.

For sample No. 6 (amount of MgO added: 0.05 parts by weight), tan was applied when an AC voltage of 2000 V / cm was applied.
δ becomes 4.0%. In addition, sample numbers 7 to 9
(In the addition amount of MgO: 0.06 to 0.70 parts by weight),
The relative permittivity εr becomes 2660 to 3050, and the dielectric loss t
an σ is 2.1% or less, temperature characteristics are within ± 13%, tan σ is 2.7% or less when an AC voltage of 2000 V / cm is applied, and insulation resistance (IR) is also 3 to 8 × 10 ⁴ M
Ω and good product range. That is, a dielectric ceramic having a high relative permittivity εr, excellent temperature characteristics, a small dielectric loss tan δ, and a small AC voltage dependency of the dielectric loss can be achieved. Further, in the sample No. 10 (amount of MgO added: 0.75 parts by weight), the dielectric loss tan δ is 1.7%, which is in the range of good products, but the relative permittivity εr is 2150. Therefore, in the present invention, barium titanate BaT
The weight of MgO added to iO ₃ is barium titanate Ba.
The range was 0.06 to 0.70 parts by weight with respect to 100 parts by weight of TiO ₃ . Sample Nos. 11 to 15 are Pr ₆ O ₁₁ added to BaTiO ₃ which is the main component of the dielectric ceramic composition.
The value was changed from 0.004 to 0.53 parts by weight.

At this time, Nb ₂ O ₅ , MgO and MnCO
The addition amounts of ₃ are 1.8 parts by weight, 0.3 parts by weight,
It was set to 0.1 parts by weight.

Sample No. 11 (Amount of Pr ₆ O ₁₁ added: 0.
004 parts by weight), the dielectric loss tan δ becomes 2.5%, but the relative dielectric constant εr becomes as low as 2410. Sample numbers 12 to 14 (amount of Pr ₆ O ₁₁ added:
0.005 to 0.52 parts by weight), the relative permittivity εr is 2
760 to 3560 and the dielectric loss tan δ is 2.0%
The temperature characteristic is within ± 11%, and the tan δ at the time of applying an AC voltage of 2000 V / cm is 2.9% or less,
The insulation resistance (IR) is 5 to 7 × 10 ⁴ MΩ, which is in the range of good products. That is, a dielectric ceramic having a high relative permittivity εr, excellent temperature characteristics, a small dielectric loss tan σ, and a small AC voltage dependency of the dielectric loss is achieved. Further, in the sample No. 15 (amount of Pr ₆ O ₁₁ added: 0.53 parts by weight), the relative dielectric constant εr was 3750 and the dielectric loss tan δ was 1.8%, which was in the range of good products, but the temperature characteristic was −22. It gets worse to%. Thus, the weight of Pr ₆ O ₁₁ added to the barium titanate BaTiO ₃ in the present invention is to provide Baruumu BaTiO ₃ 100 parts by weight titanate, 0.00
The range was 5 to 0.52 parts by weight.

In Sample Nos. 16 to 20, the amount of MnCO ₃ added to BaTiO ₃ which is the main component of the dielectric ceramic composition was changed to 0.005 to 0.40 parts by weight.

At this time, Nb ₂ O ₅ , MgO and Pr ₆ O
The amounts of ₁₁ added were 1.8 parts by weight, 0.3 parts by weight, and 0.2 parts by weight.

Sample No. 16 (Amount of MnCO ₃ added: 0.
005 parts by weight), the relative dielectric constant εr is 2960, but the dielectric loss tan δ is 2.6%. Furthermore, the insulation resistance becomes 8 × 10 ³ . In addition, sample number 17
-19 (addition amount of MnCO _3: 0.01 to 0.3 parts by weight), the relative dielectric constant εr is next 2640-2920,
Dielectric loss tan δ is 2.2% or less, and temperature characteristics are ±
Within 6%, t when AC voltage 2000 V / cm is applied
An δ of 3.0% or less, insulation resistance (IR) of 3 × 10
^It is in the range of ⁴ to 1 × 10 ⁵ MΩ, which is a good product. That is, a dielectric ceramic having a high relative permittivity εr, excellent temperature characteristics, a small dielectric loss tan δ, and a small AC voltage dependency of the dielectric loss can be achieved. Further, in sample No. 20 (amount of MnCO ₃ added: 0.40 parts by weight), the dielectric loss tan δ was 1.5%, which was in the range of good products, but the relative dielectric constant εr was 2
It will be as low as 190. Thus, the weight of MnCO ₃ added to the barium titanate BaTiO ₃ in the present invention is to provide Baruumu BaTiO ₃ 100 parts by weight titanate, ranged from 0.01 to 0.3 parts by weight.

Sample Nos. 21 to 29 are MgO of Nb ₂ O ₅
Was varied from 0.4 to 2.3. Ratio 0.4
In both cases, the relative permittivity is lower than 2310, 2130 and 2500, and the temperature characteristics are also deviated. On the other hand, the ratio is 0.5-
In the case of 2.2, the dielectric constant is 2500 or more and the temperature characteristics and other characteristics are also satisfied. Example 2 In the composition of sample No. 13 in Table 1, SiO ₂ , Al ₂ O ₃ ,
ZnO powder was added and contained as shown in Table 3 and formed into a tape shape in the same manner as in Example 1, and then the tape was laminated to form internal electrodes to prepare a laminated body. Then, each characteristic was measured in the same manner as in Example 1 and is shown in Table 4.

The composition of the sample was as follows: 1.8 parts by weight of Nb ₂ O ₅ , 0.3 parts by weight of MgO, 0.2 parts by weight of Pr ₆ O ₁₁ , and MnO per 100 parts by weight of BaTiO _3. To M
Containing 0.1 parts by weight in terms of nCO ₃ , SiO ₂ , Al ₂
A predetermined amount of O ₃ and ZnO is contained with respect to 100 parts by weight of BaTiO ₃ .

[0040]

[Table 3]

[0041]

[Table 4]

From these Tables 3 and 4, SiO ₂ , Al ₂
It can be seen that the inclusion of O ₃ and ZnO results in a lower firing temperature and a higher dielectric constant than in the case where these compounds are not included (Sample No. 13).

Example 3 BaTiO ₃ powder having an average particle size of 1.0 μm or less produced by the oxalic acid method was used as a main component, and this BaTiO ₃ 1
Nb ₂ O ₅ , MgO, Gd for 100 parts by weight
Each powder of ₂ O ₃ and MnCO ₃ was weighed as shown in Table 5, wet-milled in a ball mill for 20 to 48 hours, then an organic binder was added, and then the mixture was stirred and the thickness was measured by a doctor blade method. It was molded into a tape shape of 15 μm. This tape is cut into a size of 130 mm × 100 mm and 20 sheets are stacked to produce a laminated body.

[0044]

[Table 5]

As the internal electrodes, Ag-Pd type paste (Ag / Pd = 30/70) was printed. This laminated body was cut into 3.2 mm × 1.6 mm, and was cut in air to 124 mm.
It was baked at 0 to 1320 ° C. for 2 hours. Further, electrodes made of silver paste were baked on both end faces at 800 ° C. for 10 minutes to prepare a measurement sample.

The capacitance and the dielectric loss of the sample thus formed were measured at a reference temperature of 25 ° C. and a frequency of 1.0 k.
It was measured at Hz and a measurement voltage of 1.0 Vrms. The temperature change rate of the capacity is measured in the range of −55 to + 125 ° C.,
The capacity at + 25 ° C was used as a standard. Further, the insulation resistance was measured when a DC voltage of 25 V was applied for 1 minute.

The relative permittivity was calculated back from the capacitance. The average particle size of the sintered body is 15 on the surface of the sintered body with a scanning electron microscope.
Observe at 000 times and 500 by line intercept method.
The above particles were measured and calculated. Furthermore, frequency 1 kHz
The dielectric loss when a voltage of 2000 Vrms / cm was applied was measured. The above results are shown in Table 6.

[0048]

[Table 6]

Any of the dielectric ceramics within the scope of the present invention has a large relative permittivity of 2500 or more, and moreover, it has an EIA standard of X.
7R characteristics (capacity change rate within ± 15% in the temperature range of −55 ° C. to 125 ° C.) are satisfied. Furthermore, the dielectric loss tan
δ is as small as 2.5% or less, AC voltage 2000 Vrms
A loss of 3.0% or less is shown even under / cm. Further, the insulation resistance (IR) is 10 ⁴ MΩ or more.

In Table 5, sample numbers 44 to 48 are N added to BaTiO ₃ which is the main component of the dielectric ceramic composition.
The amount of b ₂ O ₅ added was varied from 0.7 to 2.6 parts by weight. At this time, MgO, Gd ₂ O ₃ , and MnC
The amounts of O ₃ added were 0.2 parts by weight, 0.2 parts by weight, and 0.1 parts by weight.

Sample No. 44 (Amount of Nb ₂ O ₅ added: 0.
7 parts by weight), the relative dielectric constant εr was 3530, which was a good product, but the dielectric loss tan δ was 3.0%.
Further, the temperature characteristic becomes -22%. In addition, sample numbers 45 to 47 (addition amount of Nb ₂ O ₅ : 0.8 to 2.5
(Parts by weight), the relative permittivity εr is 2720 to 3710, the dielectric loss tan δ is 2.2% or less, the temperature characteristic is within ± 13%, and the tan δ when an AC voltage of 2000 V / cm is applied is 2.7. % Or less, insulation resistance (IR) is also 6
It is in the range of good products, up to 9 × 10 ⁴ MΩ. That is, a dielectric ceramic having a high relative permittivity εr, excellent temperature characteristics, a small dielectric loss tan δ, and a small AC voltage dependency of the dielectric loss can be achieved. Further, in the sample No. 48 (addition amount of Nb ₂ O ₅ : 2.6 parts by weight), the relative permittivity ε is 2330 and the temperature characteristic is deteriorated to −18%. Therefore, in the present invention, Nb added to barium titanate BaTiO ₃ is used.
The weight of ₂ O ₅ is barium titanate BaTiO ₃ 100.
The range was 0.8 to 2.5 parts by weight with respect to parts by weight.

For sample numbers 49 to 53, the amount of MgO added to BaTiO ₃ which is the main component of the dielectric ceramic composition was varied from 0.05 to 0.75 parts by weight. At this time, the amount of Nb ₂ O ₅ added is 0.8 to 2.5 parts by weight, G
The amounts of d ₂ O ₃ and MnCO ₃ added were 0.2 parts by weight and 0.1 parts by weight, respectively.

Sample No. 49 (Amount of MgO added: 0.05
(Parts by weight) is ta when an AC voltage of 2000 V / cm is applied.
nδ will be 4.0%. Also, sample number 50-
52 (MgO addition amount: 0.06 to 0.70 parts by weight), the relative dielectric constant εr was 2710 to 3110, the dielectric loss tan σ was 2.0% or less, and the temperature characteristic was ± 12%.
Within, the tan when an AC voltage of 2000 V / cm was applied
σ is 2.6% or less, and insulation resistance (IR) is also 5 to 8 × 10.
The range is ⁴ MΩ and good products. That is, a dielectric ceramic having a high relative permittivity εr, excellent temperature characteristics, a small dielectric loss tan δ, and a small AC voltage dependency of the dielectric loss can be achieved. Further, Sample No. 53 (MgO addition amount: 0.7
5 parts by weight), the dielectric loss tan δ is 1.6%, which is in the range of good products, but the relative permittivity εr is 2190. Therefore, in the present invention, barium titanate Ba
The weight of MgO added to TiO ₃ is barium titanate B
0.06 to 0.70 with respect to 100 parts by weight of aTiO _3.
The range was parts by weight. Sample Nos. 54 to 58 are Gd ₂ O added to BaTiO ₃ which is the main component of the dielectric ceramic composition.
The addition amount of ₃ was changed from 0.004 to 0.53 parts by weight.

At this time, Nb ₂ O ₅ , MgO and MnCO
The addition amounts of ₃ are 1.8 parts by weight, 0.3 parts by weight,
It was set to 0.1 parts by weight.

Sample No. 54 (Amount of Gd ₂ O ₃ added: 0.
004 parts by weight), the dielectric loss tan δ becomes 2.3%, but the relative dielectric constant εr becomes as low as 2440. In addition, sample numbers 55 to 57 (amount of Gd ₂ O ₃ added:
0.005 to 0.52 parts by weight), the relative permittivity εr is 2
820 to 3630, and the dielectric loss tan δ is 1.9%
Below, the temperature characteristics are within ± 10%, and the tan δ when an AC voltage of 2000 V / cm is applied is 2.8% or less,
The insulation resistance (IR) is 5 to 7 × 10 ⁴ MΩ, which is in the range of good products. That is, a dielectric ceramic having a high relative permittivity εr, excellent temperature characteristics, a small dielectric loss tan σ, and a small AC voltage dependency of the dielectric loss is achieved. Further, in the sample No. 58 (amount of Gd ₂ O ₃ added: 0.53 parts by weight), the relative dielectric constant εr was 3820 and the dielectric loss tan δ was 1.7%, which was in the range of good products, but the temperature characteristic was −20. It gets worse to%. Thus, the weight of Gd ₂ O ₃ to be added to the barium titanate BaTiO ₃ in the present invention is to provide Baruumu BaTiO ₃ 100 parts by weight titanate, 0.00
The range was 5 to 0.52 parts by weight.

In sample numbers 59 to 63, the amount of MnCO ₃ added to BaTiO ₃ which is the main component of the dielectric ceramic composition was changed to 0.005 to 0.40 parts by weight.

At this time, Nb ₂ O ₅ , MgO and Gd ₂ O
The addition amount of ₃ was 1.8 parts by weight, 0.3 parts by weight, and 0.2 parts by weight.

Sample No. 59 (Amount of MnCO ₃ added: 0.
005 parts by weight), the relative dielectric constant εr is 3020, but the dielectric loss tan δ is 2.6%. Furthermore, the insulation resistance becomes 8 × 10 ³ . Also, sample number 60
To 62 (addition amount of MnCO _3: 0.01 to 0.3 parts by weight), the relative dielectric constant εr is next from 2640 to 2970,
Dielectric loss tan δ is 2.2% or less, and temperature characteristics are ±
Within 8%, t when an AC voltage of 2000 V / cm is applied
An δ of 2.9% or less, insulation resistance (IR) of 5 × 10
^It is in the range of ⁴ to 1 × 10 ⁵ MΩ, which is a good product. That is, a dielectric ceramic having a high relative permittivity εr, excellent temperature characteristics, a small dielectric loss tan δ, and a small AC voltage dependency of the dielectric loss can be achieved. Further, in the sample No. 63 (amount of MnCO ₃ added: 0.40 parts by weight), the dielectric loss tan δ is 1.5%, which is in the range of good products, but the relative dielectric constant εr is 2
It will be as low as 230. Thus, the weight of MnCO ₃ added to the barium titanate BaTiO ₃ in the present invention is to provide Baruumu BaTiO ₃ 100 parts by weight titanate, ranged from 0.01 to 0.3 parts by weight.

Sample Nos. 64 to 72 are MgO of Nb ₂ O ₅
Was varied from 0.4 to 2.3. Ratio 0.4
In both cases, the dielectric constants are lower than 2350, 2170 and 2500, and the temperature characteristics are also deviated. On the other hand, the ratio is 0.5-2.
In the case of 2, the dielectric constant is 2500 or more, and the temperature characteristics and other characteristics are also satisfied. Example 4 The composition of sample No. 56 in Table 5 was changed to SiO ₂ , Al ₂ O ₃ ,
ZnO powder was added and contained as shown in Table 7 and formed into a tape shape in the same manner as in Example 3, and then the tape was laminated to form internal electrodes to prepare a laminated body. Then, each property was measured in the same manner as in Example 3 and is shown in Table 8.

The composition of the sample was 1.8 parts by weight of Nb ₂ O ₅ , 0.3 parts by weight of MgO, 0.2 parts by weight of Gd ₂ O _{3 and} 100 parts by weight of MnO with respect to 100 parts by weight of BaTiO _3. Mn
Containing 0.1 parts by weight in terms of CO ₃ , SiO ₂ , Al ₂ O
₃ , ZnO is contained in a predetermined amount with respect to 100 parts by weight of BaTiO ₃ .

[0061]

[Table 7]

[0062]

[Table 8]

From these Tables 7 and 8, SiO ₂ , Al ₂
It can be seen that the inclusion of O ₃ and ZnO results in a lower firing temperature and a higher dielectric constant than in the case where these compounds are not included (Sample No. 56).

[0064]

As described above, according to the present invention, X7R
The characteristics are satisfied, the relative dielectric constant εr is 2500 or more, and the firing temperature is 1300 ° C. or less. As other characteristics, the dielectric loss tan δ is 2.5% or less, the insulation resistance (I
It is possible to obtain a dielectric ceramic composition in which R) is 10 ⁴ MΩ or more and tan δ is 3% or less when an AC voltage of 2000 V / cm is applied.

Thus, for example, when a monolithic ceramic capacitor is formed of the above-mentioned dielectric ceramic composition, a small-sized and large-capacity capacitor having excellent temperature characteristics can be obtained, and the firing temperature becomes 1300 ° C. or lower, and the capacitors are laminated. It is also possible to use inexpensive silver-palladium as an internal electrode between the sheets, and an inexpensive monolithic ceramic capacitor can be obtained.

Claims (3)

[Claims] 1. Nb based on 100 parts by weight of BaTiO _3.
2 O ₅ 0.80 to 2.5 parts by weight, MgO 0.06 to
0.70 parts by weight of Pr ₆ O ₁₁ or Gd ₂ O ₃ of 0.0
05 to 0.520 parts by weight, 0.01 to 0.30 parts by weight of MnO converted to MnCO ₃ , and Nb ₂
A dielectric ceramic composition characterized in that the molar ratio of O ₅ to MgO is in the range of 0.5 to 2.2. 2. The dielectric according to claim 1, further comprising 0.05 to 0.50 parts by weight of at least one of SiO ₂ and Al ₂ O ₃ with respect to 100 parts by weight of BaTiO _3. Porcelain composition. _3. Zn based on 100 parts by weight of BaTiO ₃
The dielectric porcelain composition according to claim 1 or 2, wherein O is contained in an amount of 0.5 part by weight or less.