JPH1017363A - Dielectric porcelain composition - Google Patents

Abstract

(57) Abstract: dielectric constant epsilon _r is large, a small dielectric loss, the temperature coefficient of capacitance | .tau.c | is as small as possible, yet low melting point Pd, Ag, Cu, Ni and alloys thereof Provided is a dielectric porcelain composition which can be co-sintered even if it is used as an internal electrode material. SOLUTION: The dielectric ceramic composition has a general formula: aCaO
-BBi ₂ O ₃ -cR ₂ O consisting essentially of an additive which is added to the main component and the main component having a chemical composition represented by _{3 -dTiO 2.} However, in the above general formula, R is at least one of La, Ce, Pr, Nd, Sm, Eu, and Gd, and the units of a, b, c, and d are mol% and a +
b + c + d = 100 mol%, and 11.8 ≦ a ≦ 1
6.8, 14.3 ≦ b ≦ 31.6, 0.5 ≦ c ≦ 15.
8,54.6 ≦ d ≦ 59.6. Further, the additive is used in an amount of 0.1 to 5.
0 wt% of Li ₂ O, 0.1 to 4.5 wt% of B
₂ O ₃ , 0.1-4.0 wt% SiO ₂ , and 0.1
5.5 is at least one member selected from among the weight percent of the group consisting of GeO _2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a dielectric porcelain composition, in particular, which can be sintered at a low temperature of 1050 ° C. or less, has a high dielectric constant, a high insulation resistance at room temperature, and a change in capacitance with temperature. The present invention relates to a dielectric porcelain composition having a low modulus.

[0002]

2. Description of the Related Art With the recent miniaturization of electronic devices such as mobile communication devices and AV devices, there is an increasing demand for miniaturization of electronic components. For this reason, the mainstream of electronic components such as temperature compensating capacitors has shifted to multilayer type.

Incidentally, a laminated element used in a form mounted on a printed wiring board or the like usually has a dielectric layer composed of dielectric porcelain and a binder, and a conductive layer composed of conductive powder and a binder. The electrodes are formed by alternately laminating the electrodes using a screen printing method or the like and then simultaneously sintering them.

In general, Au, Pt, P
d, Ag, Cu, Ni, or an alloy thereof is used. In order to obtain the above laminated device, it is necessary that such a conductive metal and a dielectric material can be simultaneously sintered. In particular, in order to manufacture multilayer capacitors at low cost,
A porcelain that can be sintered at as low a temperature as possible, particularly at 1050 ° C. or lower, so that an inexpensive metal containing Ag, Ni or the like as a main component can be used for the internal electrodes is required.

The electrical properties of the dielectric ceramic composition are required to have a high dielectric constant, a small dielectric loss, a high insulation resistance, and a small rate of change in capacitance with respect to temperature.

[0006]

As a dielectric ceramic generally used as a ceramic capacitor, for example, BaO-
TiO ₂ -based, TiO ₂ -ZrO ₂ -SnO ₂ -based and the like can be mentioned. However, these porcelains have a sintering temperature of 1200
It is as high as about 1400 ° C., and expensive Pd must be used for simultaneous sintering with the internal electrode.

For the purpose of simultaneous sintering with electrodes, for example, BaO—TiO ₂ —R ₂ O ₃ —PbO—Bi ₂ O
₃ , SiO ₂ , ZnO added system, BaO-TiO ₂
-Nd ₂ O ₃ in the _{Bi 2 O 3, MnO, PbO} , ZnO,
A system to which Al ₂ O ₃ is added has been proposed. However,
With the low-temperature firing materials proposed by them, it is impossible to obtain a material having a dielectric constant ε _r of 80 or more and an absolute value | τc | of a rate of change of capacitance with temperature of 150 ppm / ° C. or less.

[0008] Therefore, the technical problem of the present invention is that the dielectric constant ε
large _r , small dielectric loss, temperature coefficient of capacitance |
τc | is as small as possible and has a low melting point Pd, A
An object of the present invention is to provide a dielectric ceramic composition which can be simultaneously sintered even when g, Cu, Ni, an alloy thereof, or the like is used as an internal electrode material.

[0009]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have made the general formula: aCaO-bBi ₂ O _3-
Various investigations were conducted with a focus on dielectric ceramics represented by cR ₂ O ₃ -dTiO ₂ . Here, in this equation, R is L
at least one of a, Ce, Pr, Nd, Sm, Eu, and Gd, and the units of a, b, c, and d are mol%, a + b +
c + d = 100 mol%.

As a result of the examination, as a result of the above general formula, 1
1.8 ≦ a ≦ 16.8, 14.3 ≦ b ≦ 31.6, 0.
With respect to the total amount of main components within the range of 5 ≦ c ≦ 15.8 and 54.6 ≦ d ≦ 59.6, 0.1 to
5.0% by weight of Li ₂ O, 0.1 to 4.5% by weight of B
₂ O ₃ , 0.1-4.0 wt% SiO ₂ , 0.1
By adding at least one of GeO ₂ of about 5.5% by weight, the dielectric constant ε _r is large, the dielectric loss is small, the temperature coefficient | τc | of the capacitance is as small as possible, and Pd having a low melting point is added. , Ag, Cu, Ni and their alloys have been found to be dielectric ceramic compositions which can be co-sintered even when they are used for the internal electrode material, and the present invention has been accomplished.

[0011]

Embodiments of the present invention will be described below.

The dielectric porcelain composition of the present invention has the general formula: a
A main component having a chemical composition represented by _{CaO-bBi 2 O 3 -cR 2} O 3 -dTiO 2, in which substantially consists with an additive which is added to this main component. However,
In the above general formula, R is La, Ce, Pr, Nd, S
10. at least one of m, Eu, and Gd, and the units of a, b, c, and d are mol%; a + b + c + d = 100 mol%;
8 ≦ a ≦ 16.8, 14.3 ≦ b ≦ 31.6, 0.5 ≦
c ≦ 15.8, 54.6 ≦ d ≦ 59.6.

[0013] Further, the additive is 0.1 to 5.0% by weight of Li ₂ O, 0.1 to 5.0% by weight based on the total amount of the main components.
4.5 wt% of B ₂ O _3, 0.1~4.0 wt% of S
It is composed of at least one of iO ₂ and 0.1 to 5.5% by weight of GeO ₂ .

The dielectric porcelain composition of the present invention has a large dielectric constant ε _r , a small dielectric loss and a temperature coefficient of capacitance by being substantially composed of the main component of the above composition and the above additives. It is possible to simultaneously sinter even if Pt, Ag, Cu, Ni and their alloys having a low | τc |

Hereinafter, the production of the dielectric composition according to the embodiment of the present invention will be specifically described.

(First Embodiment) First, CaCO ₃ ,
After weighing each powder of Bi ₂ O ₃ , La ₂ O ₃ , and TiO ₂ according to each composition, using pure water, yttria-stabilized zirconia balls (hereinafter simply referred to as zirconia balls) are used in a resin ball mill. The mixture was wet-mixed for 20 hours or more to obtain a mixture. Next, after drying this mixture, it was calcined at a temperature of 800 to 900 ° C. for about 4 hours in the atmosphere to obtain a calcined product. To the calcined product, additives having a predetermined compounding ratio shown in Table 1 were added, wet-mixed (pulverized) with a zirconia ball for 20 hours or more, and dried. The powder obtained as described above was formed into a disk having a diameter of 15 mm and a thickness of about 1.5 mm, and sintered in air at a temperature of 950 to 1050 ° C. for about 2 hours. Was obtained. Thereafter, an Ag paste was baked at 800 ° C. as an electrode to obtain a measurement sample.

The composition in Table 1 below is aCaO-bB
i ₂ O ₃ -c + La ₂ O ₃ -dTiO ₂ (mol%, a +
b + c + d = 100) and the additive ratio are represented by% by weight with respect to the main component.

[0018]

[Table 1]

Next, the dielectric constant ε _r , the dielectric constant tangent (tan δ), and the temperature coefficient of capacitance τc of the dielectric ceramics of each composition were measured by the capacitance method. The temperature coefficient τc of the capacitance was obtained from the difference of the capacitance C in the temperature range of +20 to + 60 ° C. according to the following equation (1).

[0020]

(Equation 1) The measurement frequency was 1 MHz.

(Second Embodiment) CaCO ₃ , Bi ₂
Powders of O ₃ , Ce ₂ O ₃ , TiO ₂ , and additives were weighed according to each composition, and a dielectric ceramic composition having the composition shown in Table 2 below was prepared in the same manner as shown in Example 1. Obtained. Incidentally, the composition in Table _{2, aCaO-bBi 2 O 3} -cCe 2 O
_3- dTiO ₂ (mol%, where a + b + c + d = 100
Mol%) and the additive ratio are represented by% by weight with respect to the main component.

Next, the dielectric porcelain of each composition is described in the first section.
When the same measurement as that described in the embodiment was performed, the measurement results shown in Table 2 below were obtained.

[0023]

[Table 2]

(Third Embodiment) CaCO ₃ , Bi ₂
Each powder of O ₃ , Pr ₂ O ₃ , TiO ₂ , and additives was weighed according to each composition, and a dielectric ceramic having the composition shown in Table 3 below was prepared in the same manner as described in the first embodiment. The composition was obtained.
Incidentally, the composition in Table _{3, aCaO-bBi 2 O 3} -cP
r ₂ O ₃ -dTiO ₂ (mol%, where a + b + c + d
= 100 mol%) and the weight ratio of the additive to the main component
It was expressed by.

Next, the dielectric porcelain of each composition is described in the first section.
When the same measurement as that shown in the embodiment was performed, the measurement results shown in Table 3 below were obtained.

[0026]

[Table 3]

(Fourth Embodiment) CaCO ₃ , Bi ₂
Powders of O ₃ , Nd ₂ O ₃ , TiO ₂ , and additives were weighed according to the respective compositions, and the dielectric ceramics having the compositions shown in Table 4 below were measured in the same manner as described in the first embodiment. The composition was obtained.
Incidentally, the composition in Table _{4, aCaO-bBi 2 O 3} -cN
d ₂ O ₃ -dTiO ₂ (mol%, where a + b + c + d =
100 mol%) and the additive ratio are represented by% by weight with respect to the main component.

Next, the dielectric porcelain of each composition is described in the first section.
When the same measurement as that shown in the embodiment was performed, the measurement results shown in Table 4 below were obtained.

[0029]

[Table 4]

(Fifth Embodiment) CaCO ₃ , Bi ₂
Powders of O ₃ , Sm ₂ O ₃ , TiO ₂ , and additives were weighed according to each composition, and a dielectric ceramic having the composition shown in Table 5 below was measured in the same manner as in the first embodiment. The composition was obtained.
Incidentally, the composition in Table _{5, aCaO-bBi 2 O 3} -cS
m ₂ O ₃ -dTiO ₂ (mol%, where a + b + c + d
= 100 mol%) and the weight ratio of the additive to the main component
It was expressed by.

Next, the dielectric porcelain of each composition is described in the first section.
When the same measurement as that shown in the embodiment was performed, the measurement results shown in Table 5 below were obtained.

[0032]

[Table 5]

(Sixth Embodiment) CaCO ₃ , Bi ₂
Powders of O ₃ , Eu ₂ O ₃ , TiO ₂ , and additives were weighed according to the respective compositions, and the dielectric ceramics having the compositions shown in Table 6 below were measured in the same manner as described in the first embodiment. The composition was obtained.
Incidentally, the composition in Table _{6, aCaO-bBi 2 O 3} -cE
u ₂ O ₃ -dTiO ₂ (mol%, where a + b + c + d =
100 mol%) and the additive ratio are represented by% by weight with respect to the main component.

Next, the dielectric porcelain of each composition is described in the first section.
When the same measurement as that shown in the embodiment was performed, the measurement results shown in Table 6 below were obtained.

[0035]

[Table 6]

(Seventh Embodiment) CaCO ₃ , Bi ₂
Powders of O ₃ , Gd ₂ O ₃ , TiO ₂ , and additives were weighed according to each composition, and a dielectric ceramic having a composition shown in Table 7 below was measured in the same manner as described in the first embodiment. The composition was obtained.
Incidentally, the composition in the following Table _{7, aCaO-bBi 2 O 3} -cG
d ₂ O ₃ -dTiO ₂ (mol%, provided that a + b + c + d
= 100 mol%) and the weight ratio of the additive to the main component
It was expressed by.

Next, the dielectric porcelain of each composition is described in the first section.
When the same measurement as that described in the embodiment was performed, the measurement results shown in Table 7 below were obtained.

[0038]

[Table 7]

As is apparent from Table 1-7, the general formula _{aCaO-bBi 2 O 3 -cR 2} O 3 -dTiO
₂ (where R is La, Ce, Pr, Nd, Sm, Eu,
Any one of Gd, unit of a, b, c, d is mol%
When 0.5 ≦ R ₂ O ₃ ≦ 15.8 mol%, the dielectric constant ε _r is 80 or more, which is a sufficiently large value for practical use. R
_{When the} content of ₂ O ₃ is less than 0.5 mol%, it is difficult to obtain a sufficiently dense sintered body for practical use, so that it is excluded from the scope of the present invention. When R ₂ O ₃ is 0.5 mol% or more, a sufficiently dense sintered body can be obtained, and the value of the dielectric constant ε _r increases.
When R ₂ O ₃ exceeds 15.8 mol%, ε _r sharply decreases and falls below 80, and is excluded from the scope of the present invention.

Li ₂ O, B ₂ O ₂ , SiO ₂ , GeO ₂
Is less than 0.1% by weight, the sintering temperature is 1200
Since it is about ° C, it is excluded from the scope of the present invention. Li ₂
When the content of O exceeds 5.0% by weight, the content of B ₂ O ₂ exceeds 4.5% by weight, the content of SiO ₂ exceeds 4.0% by weight, and the content of GeO ₂ exceeds 5.5% by weight, the sinterability deteriorates. However, since a sufficiently dense sintered body cannot be obtained for practical use, it is excluded from the scope of the present invention. If the content of CaO is less than 14.3 mol% or more than 31.6%, a sufficiently dense sintered body cannot be obtained for practical use, and the dielectric constant is lowered, so that it is excluded from the scope of the present invention. If the content of TiO ₂ is less than 54.6 mol% or more than 59.6%, a sufficiently dense sintered body cannot be obtained for practical use, and the dielectric constant is lowered, so that it is excluded from the scope of the present invention.

In addition, Tables 1 to 7 are independent of the R ₂ O ₃ composition.
In all composition ranges, a sufficiently small dielectric loss, a sufficiently small τc, and a sufficiently large specific resistance are obtained in practical use.

[0042]

As described above, according to the present invention,
_{Formula, aCaO-bBi 2 O 3 -cR} 2 O 3 -dTi
O ₂ (where R is La, Ce, Pr, Nd, Sm, E
The unit of at least one of u and Gd, a, b, c, and d is mol%, a + b + c + d = 100 mol%, and 11.8.
≦ a ≦ 16.8, 14.3 ≦ b ≦ 31.6, 0.5 ≦ c
≦ 15.8, 54.6 ≦ d ≦ 59.6) and the total amount of the main components is 0.1 to
5.0% by weight of Li ₂ O, 0.1 to 4.5% by weight of B
₂ O ₃ , 0.1-4.0 wt% SiO ₂ , 0.1
Due to the dielectric porcelain composition to which at least one of GeO ₂ of ~ 5.5 wt% is added, the dielectric constant ε _r is large,
Pd, Ag, Cu, N with low dielectric loss, low temperature coefficient of capacitance | τc |
It is possible to provide a dielectric ceramic composition that can be simultaneously sintered even when i and an alloy thereof are used as an internal electrode material.

Claims (1)

[Claims] 1. The general formula, aCaO—bBi ₂ O ₃ —cR
₂ O ₃ -dTiO ₂ (where R is La, Ce, Pr, Nd, Sm, Eu, G
10. at least one of d, the unit of a, b, c, d is mol%, and a + b + c + d = 100 mol%;
8 ≦ a ≦ 16.8, 14.3 ≦ b ≦ 31.6, 0.5 ≦
c ≦ 15.8, 54.6 ≦ d ≦ 59.6), and a main component having a chemical composition represented by the formula: and an additive added to the main component. Is 0.1 to 5.0% by weight of Li based on the total amount of the main components.
₂ O, 0.1 to 4.5 wt% of B ₂ O _3, 0.1~4.
0% by weight of SiO _2, and 0.1 to 5.5% by weight of Ge
At least selected from among the group consisting of O ₂ dielectric ceramic composition, which is a kind.