JPH08198667A - Dielectric porcelain composition - Google Patents

Abstract

PURPOSE: To obtain such a dielectric porcelain material that has a high dielectric const. εr , almost zero temp. coefft. τf of resonance frequency and large Q×f and can be simultaneously sintered even when metals having low melting point such as Au, Ag and Cu or alloys of these are used as the inner electrode material. CONSTITUTION: This dielectric porcelain compsn. consists of the main component comprising BaO, rare earth oxide (R2 O3 , wherein R is at least one king of rare earth element including Nd as the essential component), Bi2 O3 and TiO2 , and an additive. The main component is expressed by general formula aBaO-bR2 O3 -cBi2 O3 -dTiO2 (c=0.8 to 6.3mol% and a+b+c+d=100mol%) and (a), (b+c) and (d) are present in the area defined by the four points P, Q, R, S in the figure. The additive is B2 O3 in an amt. of 0.1-5.0wt.% to the whole weight. This porcelain compsn. contains orthorhombic crystals by >=85vol.%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric ceramic material mainly used for communication and broadcasting equipment for microwave band.

[0002]

2. Description of the Related Art In recent years, with the spread of mobile communication such as car phones and mobile phones due to the progress of communication technology, the frequency band used for communication has reached the microwave band.

Conventionally, a cavity resonator or the like has been used as a circuit component used in the microwave band. However,
Since these parts are as large as the wavelength of microwaves, they are used in automobile phones, mobile phones, and small global positioning systems (hereinafter referred to as G
It was impossible to miniaturize the parts applicable to devices such as PS).

On the other hand, by using a dielectric resonator in a microwave filter or a frequency stabilizing circuit of an oscillator, miniaturization of circuit parts has been actively carried out and is being put to practical use.

The characteristics required of such a microwave dielectric material are that the dielectric constant ε _r in the operating frequency band is large, the temperature coefficient τ _r of the resonance frequency is as close to zero as possible, and the dielectric constant in the microwave band is Loss tan δ (= 1 /
Q) is small, that is, the Q value (normally expressed in the form of Q × f, f is a resonance frequency) is large.

Conventionally, as a dielectric ceramic material for microwaves having a high dielectric constant, BaO-rare earth oxide-TiO ₂
Although materials of the system are known, the materials having the compositions disclosed so far have a poor balance of ε _r and Q × f. In order to solve the drawback, the present inventor has proposed that BaO, SrO,
A dielectric porcelain that limits the composition of Nd ₂ O ₃ , didymium oxide, Bi ₂ O ₃ , and TiO ₂ and has an orthorhombic ratio of 85% or more in volume fraction is proposed (Patent application Flat 6-17
1600).

[0007]

By the way, in order to further miniaturize the microwave circuit, a method using an LC element is effective, and the ceramic lamination technology which has already been put to practical use is applied. It can be realized by doing. For example, by forming a metal pattern on a thin ceramic layer and stacking several metal patterns, a laminated ceramic circuit component having various shapes can be manufactured.

However, the electrodes of the device used in the microwave band generally have good conductivity such as Au, Ag, and C.
u and their alloys are used, and the above LC
In order to obtain an element or the like, it is necessary that such an electrode material having a relatively low melting point and a dielectric material can be co-sintered.

However, in order to obtain a sufficient sintering density and a large dielectric constant ε _r with the above-mentioned dielectric material,
It had to be sintered at up to 1500 ° C, and there was a drawback that Au, Ag, Cu, etc. could not be used as internal electrode materials.

Therefore, the technical problem of the present invention is that the dielectric constant ε
Au having a large _r , a temperature coefficient τ _f of the resonance frequency as close to zero as possible, a large Q × f value, and a low melting point,
An object of the present invention is to provide a dielectric ceramic material that can be co-sintered even when Ag, Cu, or an alloy thereof is used as an internal electrode material.

[0011]

In order to solve the above problems, the present inventor has added B ₂ O ₃ to
Au, A having a large dielectric constant ε _r , a temperature coefficient τ _f of the resonance frequency close to zero, a large Q × f value, and a low melting point
The inventors have found that a dielectric ceramic material that can be co-sintered can be obtained even if g, Cu, or an alloy thereof is used as an internal electrode material, and the present invention has been accomplished.

That is, according to the present invention, (1) BaO, R
_A porcelain composition comprising a main component containing ₂ O ₃ (where R is a rare earth oxide containing Nd as an essential component), Bi ₂ O ₃ and TiO ₂ , and an additive, the main component being generally in the _{formula, aBaO-bR 2 O 3 -cBi} 2 O 3 -dTiO
₂ (however, c = 0.8 to 6.3 mol%, a + b + c + d
= 100 mol%), and a, (b + c) and d are shown in FIG.
As shown in Table 3, P, Q, R, and S shown in Table 3 below are in a range formed by connecting them, and the additive is 0.1 to 5.0 wt% of B ₂ O _{3 with} respect to the total amount. The above-mentioned porcelain composition is a dielectric porcelain composition having a volume fraction of 85% or more being orthorhombic.

[0013]

[Table 3]

According to the invention, (2) the above (1)
The dielectric ceramic composition described above, wherein the rare earth oxide R
₂ O ₃ dielectric ceramic composition characterized in that it consists essentially Nd ₂ O ₃ is obtained.

According to the invention, (3) the above (2)
The dielectric ceramic composition described above, wherein the rare earth oxide R
A dielectric ceramic composition is obtained in which ₂ O ₃ is substantially composed of didymium oxide (Nd + Pr) ₂ O ₃ .

According to the invention, (4) the above (1)
To (3) dielectric ceramic composition wherein the main component, a portion of BaO of the main component was replaced with SrO, with the general _{formula, aBaO-eSrO-bR 2 O} 3 -cB
i ₂ O ₃ -dTiO ₂ (where, e = 0.1 to 3.5 mole%, c = 0.8~6.3 mole%, a + e + b + c + d =
100 mol%), (a + e), (b + c), d are within the range formed by connecting the four points P, Q, R, and S in Table 4 in FIG. 2 below. Is obtained.

[0017]

[Table 4]

[0018]

As described above, in the present invention, the main component is a
_{BaO-bR 2 O 3 -cBi 2} O 3 -dTiO 2 or a
_{BaO-eSrO-bR 2 O 3} -cBi 2 O 3 -dTi
B ₂ O ₃ is added to the porcelain composition represented by O ₂ at 0.1 to
By adding 5.0% by weight, the sintering temperature of 1300 to 1500 ° C., which was necessary to obtain the optimum dielectric constant ε _r ,
It can be lowered to 1000 to 1200 ° C.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a three-component system phase diagram showing an example of the main components of the dielectric ceramic composition of the present invention. Referring to FIG. 1, the dielectric ceramic composition was BaO, R ₂ O ₃ (where R is Nd
Is a porcelain composition comprising a main component containing Bi ₂ O ₃ and TiO ₂ and an additive. The main component in the general formula, aBaO-bR ₂ O
_{3 -cBi 2} O _{3 -dTiO 2} (where, c = 0.8 to
6.3 mol%, a + b + c + d = 100 mol%). This a, (b + c), d is P, shown in Table 5 below.
It is within the range formed by connecting the four points of Q, R, and S, and it is as shown in FIG. 1 when shown in a ternary system phase diagram.

Further, in the porcelain composition of the present invention, the amount of the additive added to the main component is 0.1 based on the total amount.
5.0 consists wt% of B ₂ O _3. And, in this porcelain composition, 85% or more in volume fraction is orthorhombic.

[0022]

[Table 5]

Another example of the dielectric ceramic composition of the present invention is the dielectric ceramic composition, wherein the rare earth oxide R ₂ O ₃ is substantially composed of Nd ₂ O ₃ .

Another example of the dielectric ceramic composition of the present invention is the dielectric ceramic composition, wherein the rare earth oxide R ₂ O ₃ is substantially didymium oxide (Nd + Pr) ₂ O _3.
Consists of

According to still another example of the dielectric composition of the present invention, in each example of the dielectric porcelain composition, the main component is a part of BaO in the main component.
In the general formula substituted with rO, aBaO-eSrO-bR
₂ O ₃ -cBi ₂ O ₃ -dTiO ₂ (however, e = 0.1
~ 3.5 mol%, c = 0.8-6.3 mol%, a + e +
b + c + d = 100 mol%). This (a +
e), (b + c) and d are within the range formed by connecting the four points P, Q, R and S in Table 6 below. Here, this main component is shown as in FIG.

[0026]

[Table 6]

In still another example of the dielectric ceramic composition of the present invention, the additive added to the main component is 0.1 to 5.0% by weight of B ₂ O _{3 based on} the total amount. Become.
And, in this porcelain composition, 85% or more in volume fraction is orthorhombic.

Next, specific examples of the production of the dielectric ceramic composition of the present invention will be described.

Example 1 First, BaCO ₃ and Nd ₂ O
Powders of ₃ , Bi ₂ O ₃ , TiO ₂ , and SnO ₂ were weighed according to each composition, and then pure water was used to wet-mix with a ball mill made of resin with a balconia ball to obtain a mixture. Next, after drying this mixture, it was heated to 1150 ° C in the atmosphere.
It was calcined at the temperature of about 4 hours to obtain a calcined product. Next, B ₂ O
The powders of ₃ were weighed so as to have the ratios shown in Table 7 below, added to the calcined product, and wet-ground (mixed) with the above ball mill. This was molded into a disk shape having a diameter of 15 mm and a thickness of about 6 mm, and sintered in the atmosphere at a temperature of 1000 to 1375 ° C. for about 2 hours to obtain a dielectric ceramic material.
The composition in Table 7, the general formula aBaO-bNd ₂ O
_{3 -cBi 2} O _{3 -dTiO 2} (where the mole%, a + b
+ C + d = 100).

[0030]

[Table 7]

Next, with respect to the dielectric porcelain having each composition, the dielectric constant ε _r , the Q × f value, and the temperature coefficient τ _f of the resonance frequency were measured by the dielectric resonator method. Resonance frequency temperature coefficient τ _f
Was calculated from the difference of the resonance frequency f in the temperature range of 0 to + 40 ° C. by the following formula 1.

[0032]

[Equation 1]

The measurement results are shown in Table 7 above. The resonance frequency was 2.5 to 3.5 GHz.

(Example 2) BaCO ₃ , (Nd + Pr)
₂ O ₃ (didymium oxide), Bi ₂ O ₃ , TiO ₂ , SnO
Each powder of ₂ was weighed according to each composition, and a calcined product was obtained by the same method as shown in Example 1. Next, the powders of B ₂ O ₃ were weighed so as to have the ratios shown in Table 8 below, added to the calcined product, wet-ground (mixed) with the same ball mill as shown in Example 1, and then molded. , And sintered to obtain dielectric porcelain having the composition shown in Table 8 below. The composition in Table 8 below is
aBaO-b (Nd + Pr) 2 O 3 -cBi 2 O 3 -d
It is expressed as TiO ₂ (mol%, a + b + c + d = 100).

[0035]

[Table 8]

Next, the same measurements as those shown in Example 1 were carried out for the dielectric ceramics having the respective compositions, and the measurement results shown in Table 7 were obtained. The analysis values of didymium oxide are shown in Table 9 below, and the weighing was performed by converting Pr ₂ O ₃ into 1 mol.

[0037]

[Table 9]

Example 3 BaCO ₃ , SrO, Nd ₂
Powders of O ₃ , Bi ₂ O ₃ , TiO ₂ , and SnO ₂ were weighed according to each composition, and a calcined product was obtained by the same method as shown in Example 1. Next, the powders of B ₂ O ₃ were weighed so as to have the proportions shown in Table 10 below, added to the calcined product, wet-ground (mixed) with the same ball mill as shown in Example 1, and then molded. , And sintered to obtain dielectric porcelain having the composition shown in Table 10 below. The composition in Table 10 below is aBaO.
_{-ESrO-bNd 2 O 3 -cBi 2} O 3 -dTiO 2
It is expressed as (mol%, a + e + b + c + d = 100).

Next, the dielectric porcelain having each composition was measured in the same manner as in Example 1, and the measurement results shown in Table 10 below were obtained.

[0040]

[Table 10]

(Example 4) BaCO ₃ , SrO, (Nd
+ Pr) ₂ O ₃ (didymium oxide), Bi ₂ O ₃ , Ti
Each powder of O ₂ and SnO ₂ was weighed according to each composition, and a calcined product was obtained by the same method as shown in Example 1. Next, B
₂ O ₃ powders were weighed so as to have the proportions shown in Table 11, added to the calcined product, wet-milled (mixed) with the same ball mill as shown in Example 1, then molded and sintered, The dielectric ceramics having the compositions shown in Table 11 below were obtained. Table 11
In composition, aBaO-eSrO-b (Nd + Pr) 2 O
_{3 -cBi 2} O _{3 -dTiO 2} (mole%, a + e + b +
c + d = 100).

Next, with respect to the dielectric porcelain having each composition, the same measurement as that shown in Example 1 was performed, and Table 11
The measurement results shown in are obtained. The analysis values of didymium oxide are as shown in Table 9 above, and the weighing was performed by converting Pr ₂ O ₃ into 1 mol.

[0043]

[Table 11]

As is clear from the above Examples 1 to 4, B
_{aO-R 2 O 3 -Bi 2} O 3 -TiO 2, or Ba
By adding 0.1 to 5.0 wt% of B ₂ O ₃ to the main component of O—SrO—R ₂ O ₃ —Bi ₂ O ₃ —TiO ₂ , the dielectric constant ε _r is large and Q × The f value is large, the temperature coefficient τ _f of the resonance frequency is close to zero, and 1000 to 120
It is possible to obtain a dielectric ceramic that can be sintered at a low temperature of 0 ° C.

On the other hand, in Comparative Examples other than the samples according to Examples 1 to 4 of the present invention, when the addition amount was less than 0.1% by weight, the effect of the addition was not obtained and the sintering temperature was 1200 ° C.
Will exceed. Further, when the added amount exceeds 5.0% by weight, the dielectric constant ε _r and Q × f value are significantly reduced.

[0046]

As described above, according to the present invention,
Au, A having a large dielectric constant ε _r , a temperature coefficient τ _f of the resonance frequency close to zero, a large Q × f value, and a low melting point
It is possible to provide a dielectric ceramic composition that can be co-sintered even when g, Cu, or an alloy thereof is used as an internal electrode material.

[Brief description of drawings]

FIG. 1 is a ternary system phase diagram showing a composition range of an example of a main component of a dielectric ceramic composition of the present invention.

FIG. 2 is a ternary system phase diagram showing a composition range of another example of the main component of the dielectric ceramic composition of the present invention.

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] March 13, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0029

[Correction method] Change

[Correction content]

Example 1 First, BaCO ₃ and Nd ₂ O
_3, Bi 2 _{O 3,} after the respective powders of Ti O ₂ were weighed according to the composition, with pure water, and wet-mixed with a resin ball mill balcony A ball, to obtain a mixture. Next, this mixture was dried and then calcined in the atmosphere at a temperature of 1150 ° C. for about 4 hours to obtain a calcined product. Next, the powders of B ₂ O ₃ were weighed so as to have the ratios shown in Table 7 below, added to the calcined product, and wet-ground (mixed) with the above ball mill.
This was molded into a disk shape having a diameter of 15 mm and a thickness of about 6 mm, and was sintered in the atmosphere at a temperature of 1000 to 1375 ° C. for about 2 hours to obtain a dielectric ceramic material. The composition in Table 7, the general formula _{aBaO-bNd 2} O 3 -cB
i ₂ O ₃ -dTiO ₂ (where the mole%, a + b + c + d
= 100).

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0034

[Correction method] Change

[Correction content]

(Example 2) BaCO ₃ , (Nd + Pr)
Powders of ₂ O ₃ (didymium oxide), Bi ₂ O ₃ and TiO ₂ were weighed according to each composition, and a calcined product was obtained by the same method as shown in Example 1. Next, the powders of B ₂ O ₃ were weighed so as to have the ratios shown in Table 8 below, added to the calcined product, wet-ground (mixed) with the same ball mill as shown in Example 1, and then molded. , And sintered to obtain dielectric porcelain having the composition shown in Table 8 below. The composition in Table 8 below is aBaO.
_{-B (Nd + Pr) 2 O} 3 -cBi 2 O 3 -dTiO 2
It is expressed as (mol%, a + b + c + d = 100).

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0038

[Correction method] Change

[Correction content]

Example 3 BaCO ₃ , SrO, Nd ₂
Each powder of O ₃ , Bi ₂ O ₃ and TiO ₂ was weighed according to each composition, and a calcined product was obtained by the same method as shown in Example 1. Next, the powders of B ₂ O ₃ were weighed so as to have the proportions shown in Table 10 below, added to the calcined product, and wet-ground (mixed) with the same ball mill as shown in Example 1,
Molding and sintering were carried out to obtain dielectric porcelain having the composition shown in Table 10 below. In Table 10, the composition is aBaO-eSrO-
_{bNd 2 O 3 -CBi 2 O 3} -dTiO 2 ( mole%, a
+ E + b + c + d = 100).

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0041

[Correction method] Change

[Correction content]

(Example 4) BaCO ₃ , SrO, (Nd
+ Pr) ₂ O ₃ (didymium oxide), Bi ₂ O ₃ , TiO ₂
It weighed in accordance with the powders of the respective compositions to obtain a calcined product in a manner similar to that shown in the first embodiment. Next, the powders of B ₂ O ₃ were weighed so as to have the proportions shown in Table 11, added to the calcined product, wet-ground (mixed) with the same ball mill as shown in Example 1, and then molded, Sintering was performed to obtain dielectric porcelain having the composition shown in Table 11 below. The composition in Table 11 is aB
_{aO-eSrO-b (Nd +} Pr) 2 O 3 -cBi 2 O
_3- dTiO ₂ (mol%, a + e + b + c + d = 10
0).

Claims (4)

[Claims] 1. A main component containing BaO, a rare earth oxide (R ₂ O ₃ , where R is at least one of rare earth elements containing Nd as an essential component), Bi ₂ O ₃ , and TiO ₂ . a ceramic composition comprising a additive, the main component is a general _{formula, aBaO-bR 2 O 3 -cBi} 2 O 3 -
dTiO ₂ (however, c = 0.8 to 6.3 mol%, a + b
+ C + d = 100 mol%), a, (b + c),
d is in a range formed by connecting four points P, Q, R and S in Table 1 below in FIG. 1, and the additive is 0.1 to 5.0% by weight of B ₂ O based on the total amount. _{3. The} dielectric porcelain composition according to claim ₃ , wherein the porcelain composition is orthorhombic at a volume fraction of 85% or more. [Table 1] 2. The dielectric ceramic composition according to claim 1, wherein the rare earth oxide R ₂ O ₃ consists essentially of Nd ₂ O ₃ . 3. The dielectric ceramic composition according to claim 1, wherein the rare earth oxide R ₂ O ₃ is substantially composed of didymium oxide (Nd + Pr) ₂ O ₃ . 4. The dielectric ceramic composition according to claim 1, wherein the main component is a BaO in the general formula in which a part of BaO in the main component is replaced with SrO.
_{-ESrO-bR 2 O 3 -cBi 2} O 3 -dTiO
₂ (However, e = 0.1-3.5 mol%, c = 0.8-
6.3 mol%, a + e + b + c + d = 100 mol%), and (a + e), (b + c), d are within the range formed by connecting the four points P, Q, R, and S in Table 2 below in FIG. A dielectric porcelain composition characterized by being. [Table 2]