JPH05182524A - Dielectric porcelain composition for temperature compensation - Google Patents

Abstract

PURPOSE:To provide a dielectric porcelain composition for temperature compensation of excellent characteristic by sintering, allowing no reduction, at a low temperature of 1050 deg.C or less in a neutral or reductive environment of low oxygen partial pressure. CONSTITUTION:A dielectric porcelain composition for temperature compensation contains 22-43 parts by weight of TiO2, 38-58 parts by weight of ZrO2, and 9-26 parts by weight of SnO2 as a main component, and contains 5-35 parts by weight of a metallic oxide including at least one kind of the metallic oxide selected from B2O3, SiO2, and LiO2 as a sub-component which is added to 100 parts by weight of main component. The dielectric porcelain composition has 50ppm/ deg.C or less of temperature coefficient of dielectric constant in absolute value 2500 or more of Q value at 1MHz, and 1X10<12>OMEGAcm or more of specific resistance value at 20 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature-compensating dielectric ceramic composition, and more particularly, for example, a laminated capacitor and a laminated LC.
The present invention relates to a dielectric ceramic composition for temperature compensation used as a dielectric ceramic of a filter.

[0002]

2. Description of the Related Art Heretofore, as this type of temperature compensating dielectric porcelain composition, a MgTiO ₃ —CaTiO ₃ system porcelain composition has been used.

[0003]

However, MgT
The iO ₃ -CaTiO ₃ -based porcelain composition has a high sintering temperature of 1300 ° C. or higher, and when calcinated under a neutral or reducing low oxygen partial pressure, the porcelain is reduced and becomes a semiconductor. Had a point.

Therefore, as a material for the internal electrodes, a metal which is not melted at a temperature at which the dielectric ceramic material is sintered and which is not oxidized even when fired under a high oxygen partial pressure at which the dielectric ceramic material does not become a semiconductor must be used. I have to. Therefore, when using a conventional material as a dielectric ceramic of a multilayer capacitor, expensive platinum or palladium, which has a high melting point and is difficult to oxidize at high temperature, must be used as a material for the internal electrodes.
This has been a major obstacle to lowering the price of multilayer capacitors.

Therefore, in order to solve the above problems,
It has been desired to change the material of the internal electrodes from an expensive noble metal to an inexpensive base metal such as nickel or copper. However, using such a base metal as a material for the internal electrodes,
If fired under conventional conditions, the electrode material will oxidize and melt. Therefore, in order to use such a base metal as a material for the internal electrode, even if it is fired at a low temperature in a neutral or reducing atmosphere with a low oxygen partial pressure, it does not become a semiconductor, and as a dielectric ceramic material for a capacitor. There has been a need for a dielectric porcelain composition having sufficient specific resistance and excellent dielectric properties.

A dielectric ceramic composition for solving this kind of problem is disclosed in JP-A-1-102806. This dielectric ceramic composition can be fired in a neutral or reducing atmosphere having a low oxygen partial pressure. Therefore, using this dielectric ceramic composition, it is possible to provide a temperature compensating multilayer capacitor using a base metal such as nickel or copper as a material for the internal electrodes. But,
Although this dielectric ceramic composition solves the above-mentioned problems with respect to the firing temperature and the temperature coefficient of the dielectric, it has a Q value of 1
It was as small as 2000 or less at MHz.

Therefore, the main object of the present invention is to achieve the following effects in a neutral or reducing atmosphere with a low oxygen partial pressure:
Sintered at a low temperature of 050 ° C or lower without being reduced, and the absolute value of the temperature coefficient of the dielectric constant is 50 ppm / ° C or lower,
A dielectric ceramic composition for temperature compensation, which makes it possible to obtain a dielectric ceramic having a Q value of 2500 or more at 1 MHz and a specific resistance value of 1 × 10 ¹² Ωcm or more at 20 ° C. and using a base metal such as copper as an internal electrode. Is to provide.

[0008]

The present invention is directed to TiO ₂ 2
_{2 to} 43 parts by weight, ZrO ₂ 38 to 58 parts by weight, SnO ₂
9 to 26 parts by weight as a main component, and as main components 100 parts by weight, B ₂ O ₃ , SiO ₂ , Li as secondary components.
_A dielectric ceramic composition for temperature compensation, comprising 5 to 35 parts by weight of a metal oxide containing at least one selected from ₂ O.

[0009]

According to the present invention, sintering is performed in a neutral or reducing atmosphere having a low oxygen partial pressure at a low temperature of 1050 ° C. or less without being reduced, and the absolute value of the temperature coefficient of capacitance is obtained. Is 50 ppm / ° C or less and the Q value is 25 at 1 MHz.
And a specific resistance value at 20 ° C. of 1 × 10 ¹²
A temperature-compensating dielectric porcelain composition capable of obtaining a dielectric porcelain having a characteristic of Ωcm or more is obtained.

Therefore, if this temperature-compensating dielectric ceramic composition is used as a material for a laminated capacitor, a base metal such as copper can be used as an internal electrode. Therefore, it is possible to eliminate an increase in the cost of the electrodes due to the increase in the capacity of the multilayer capacitor, and it is possible to provide a low-cost multilayer capacitor. Further, the dielectric ceramic obtained from this temperature-compensating dielectric ceramic composition has a high Q value and a small temperature coefficient of the dielectric constant. Therefore, by using an electrode having a high conductivity such as silver, copper or gold, it can be used as a material for a laminated LC filter, an RF module or the like used in the microwave region.

The above-mentioned objects, other objects, features and advantages of the present invention will become more apparent from the detailed description of the following embodiments with reference to the drawings.

[0012]

EXAMPLE First, as a starting material for the main component, a purity of 99.
5% or more of TiO ₂ , ZrO ₂ , and SnO ₂ were compounded so as to have the compounding ratios shown in Table 1, respectively.

[0013]

[Table 1]

Further, B ₂ O ₃ and S are used as materials for the subcomponents.
iO ₂ , Li ₂ O, BaO, ZnO, CuO, MnO,
CaO was prepared. These materials were weighed so as to have the ratio shown in Table 2, wet-mixed with a ball mill, pulverized, and then evaporated to dryness.
Melted at ° C. Further, the melted material was wet pulverized to 1 μm or less by a ball mill and then evaporated and dried to obtain two kinds of subcomponents of A series and B series.

[0015]

[Table 2]

The obtained main component and subcomponents were blended in the proportions shown in Table 1 to obtain blended raw materials.

5 parts by weight of a vinyl acetate binder as a binder was added to this blended raw material and wet mixed in a ball mill to obtain a mixture. Further, this mixture was evaporated and dried, and then sized to obtain a powder raw material. 2ton /
A disk-shaped product having a diameter of 20 mm and a thickness of 1.0 mm was formed at a pressure of cm ² to obtain a formed product.

Next, the disk-shaped molded product was placed in an alumina-based box having zirconia powder as a floor powder, and a vinyl acetate binder was burned for 2 hours at 500 ° C. in a natural atmosphere. Then, in a reducing gas atmosphere with a volume ratio of N ₂ : H ₂ = 3: 100, the disc-shaped molded product was 900-1
A device was obtained by firing at 050 ° C. for 2 hours. Further, an In—Ga alloy was applied to both main surfaces of the obtained device to form electrodes, and a sample (capacitor) was produced.

With respect to the obtained sample, dielectric constant ε, Q value, temperature coefficient of dielectric constant α (ppm / ° C.), 20 ° C.
Was measured for each characteristic of specific resistance ρ ₂₀ (Ωcm).

The dielectric constant ε and the Q value have a frequency of 1 MH.
It was measured under the conditions of z, voltage 1 Vrms, and temperature 20 ° C.
Further, the temperature coefficient α (ppm / ° C.) of the dielectric constant is the electrostatic capacitance C _{20 at 20} ° C. and the electrostatic capacitance C _{85 at} 85 ° C.
It was calculated from the following formula. α (ppm / ° C.) = {(C ₈₅ −C ₂₀ ) / C ₂₀ } × {1 / (85−20)} × 10 ⁶

Furthermore, the specific resistance at 20 ° C. ρ ₂₀ (Ωc
m) was obtained from the value of the current flowing when a DC voltage of 500 V was applied at 20 ° C. The results are shown in Table 3.

[0022]

[Table 3]

Those marked with * in Tables 1 and 3 are outside the scope of the present invention, and others are within the scope of the present invention.

The composition of the main component of each sample shown in Table 1 is shown in FIG. 1 by a three-component composition diagram. In this drawing
The number with a mark shows each sample number.

Further, in FIG. 1, regions showing the composition ratio of the main components of the composition of the present invention are represented by composition points A, B, C, D, and
It is shown by a polygon with E and F as vertices.

The composition according to the present invention contains 100 parts by weight of the main component as an auxiliary component such as B ₂ O ₃ and S.
5 to 35 parts by weight of a metal oxide containing at least one selected from iO ₂ and Li ₂ O is added.

Next, the reason why the numerical values of the components of the dielectric ceramic composition for temperature compensation according to the present invention are limited as described above will be explained.

If the amount of TiO ₂ is less than 22 parts by weight, the sinterability is poor and a dense sintered body cannot be obtained even if fired at a temperature of 1050 ° C. (see Sample No. 17). Further, if TiO ₂ exceeds 43 parts by weight, the temperature coefficient becomes large and the specific resistance becomes less than 10 ¹² Ωcm, which is not preferable (see Sample No. 1).

When ZrO ₂ is less than 38 parts by weight, the temperature coefficient becomes large, which is not preferable. Also, ZrO ₂ is 58
If the amount is more than parts by weight, the sinterability is poor and a dense sintered body cannot be obtained even if fired at a temperature of 1050 ° C. (see Sample No. 11).

If SnO ₂ is less than 9 parts by weight or more than 26 parts by weight, the temperature coefficient becomes large and the specific resistance becomes less than 10 ¹² Ωcm, which is not preferable (see Sample No. 14).

If the amount of the A series subcomponent added is less than 5 parts by weight with respect to 100 parts by weight of the main component, the sinterability is poor and 10
Even if fired at a temperature of 50 ° C., a dense sintered body cannot be obtained, which is not preferable (see Sample No. 18). Further, when the amount of the auxiliary component of the A series exceeds 35 parts by weight, the Q value becomes 25.
It is less than 00, which is not preferable (see Sample No. 21).

If the amount of the B series subcomponent added is less than 5 parts by weight with respect to 100 parts by weight of the main component, the sinterability is poor and 10
Even if it is fired at a temperature of 50 ° C., a dense sintered body cannot be obtained, which is not preferable. Also, the addition amount of the B series subcomponent is 3
When it exceeds 5 parts by weight, the Q value becomes less than 2500 and the specific resistance becomes less than 10 ¹² Ωcm, which is not preferable (see Sample No. 25).

Although the metal oxide powder was used as a subcomponent in the above-mentioned embodiment, a solution may be added in addition to the powder. Further, although the sub-components are used by virtue of melting and pulverizing each material to be vitrified, they may be added to the main component as they are.

[Brief description of drawings]

FIG. 1 is a three-component composition diagram showing the mixing ratio of the main components of the composition of the present invention.

Claims (1)

[Claims] 1. 22 to 43 parts by weight of TiO ₂ and ZrO ₂ 3
8 to 58 parts by weight, SnO ₂ 9 to 26 parts by weight as a main component, and B ₂ as a subcomponent with respect to 100 parts by weight of the main component.
O _3, SiO _2, Li ₂ metal oxide containing at least one selected from among O were added 5 to 35 parts by weight, temperature compensating dielectric ceramic composition.