JPH09157005A - Dielectric porcelain composition - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To obtain Au, Ag, Cu having a large dielectric constant ε _r , a temperature coefficient τ _{f of} resonance frequency as close to zero as possible, a large Q × f value, and a low melting point, and To provide a dielectric ceramic composition that can be co-sintered even when an alloy or the like is used as an internal electrode material. A dielectric porcelain composition comprises a main component porcelain composition and an additive. The main component porcelain composition is BaO, Nd
At least one of the rare earth oxides containing as an essential component
Species (R ₂ O ₃ ), Bi ₂ O ₃ , and TiO ₂ as the main components, and the general formula is 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 4 of P, Q, R, and S in the three-component system phase diagram of FIG.
It is within the range of connecting dots. Also, G as an additive
eO ₂ is contained in a proportion of 0.05 to 8.0% by weight based on the total amount.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric porcelain composition mainly used for communication and broadcasting equipment for a 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 have the same size as the wavelength of microwaves, it was impossible to miniaturize the parts applicable to automobile phones, mobile phones, small GPS devices, and the like.

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 frequency band used is large, the temperature coefficient τ _f of the resonance frequency is as close to zero as possible, and the dielectric constant in the microwave band. 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,
We have proposed a dielectric porcelain that limits the composition of Nd ₂ O ₃ , didymium oxide, Bi ₂ O ₃ , and TiO ₂ and that is 85% or more in volume fraction is orthorhombic (Patent application 6 -1716
No. 00).

[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 into 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,
There is a problem that Au, Ag, Cu, etc. cannot be used as the internal electrode material because they must be sintered at up to 1500 ° C.

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

[0011]

In order to solve the above-mentioned problems, the present inventor has added GeO ₂ to
Au, A having a large dielectric constant ε _r , a temperature coefficient τ _{f of} resonance frequency close to zero, a large Q × f value, and a low melting point
It has been found that a dielectric ceramic material that can be co-sintered can be obtained even when g, Cu, or an alloy thereof is used as an internal electrode material.

That is, according to the present invention, BaO, R ₂ O ₃
(Rare earth oxide containing Nd as an essential component), Bi ₂ O
₃ and TiO ₂ as main components, the general formula is aB
_{aO-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 P, Q, R and S shown in Table 2 below in the ternary phase diagram. The first main component porcelain composition within the range formed by connecting the four points of
A dielectric ceramic composition containing GeO ₂ as an additive in a proportion of 0.05 to 8.0% by weight is obtained.

[0013]

[Table 2]

Further, in the present invention, in the dielectric ceramic composition, the rare earth oxide (R ₂ O ₃ ) is Nd.
₂ O ₃ or didymium oxide {(Nd + P
A dielectric porcelain composition characterized by comprising r) ₂ O ₃ } is obtained.

Further, according to the present invention, in any one of the above dielectric ceramic compositions, B of the first main component ceramic material is used instead of the first main component ceramic composition.
The general formula in which a part of aO is replaced with SrO is (ae)
_{BaO-eSrO-bR 2 O 3} -cBi 2 O 3 -dTi
A dielectric porcelain composition characterized by having a second main component porcelain composition represented by O ₂ (where e = 0.1 to 3.5 mol%) is obtained.

[0016]

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

FIG. 1 is a diagram showing a first main component porcelain composition of a dielectric porcelain composition according to an embodiment of the present invention. The dielectric ceramic composition shown in FIG. 1 comprises a first main component ceramic composition and an additive. This main component porcelain composition contains BaO, R ₂ O ₃ (rare earth oxide containing Nd as an essential component), Bi ₂ O ₃ and TiO ₂ as main components, and has a general formula of aBaO-bR ₂ O ₃ -CBi ₂ O ₃
-DTiO ₂ (where, c = from 0.8 to 6.3 mol%, a +
b + c + d = 100 mol%). Here, in the ternary system phase diagram of FIG.
(B + c) and d are P, Q, R, and S shown in Table 3 below.
It is within the range formed by connecting the four points.

The dielectric ceramic composition of the present invention contains GeO ₂ as an additive in a proportion of 0.05 to 8.0% by weight based on the total amount.

[0019]

[Table 3]

In the first embodiment of the dielectric porcelain composition of the present invention, the R ₂ O ₃ comprises Nd ₂ O ₃ , and in the second embodiment of the dielectric porcelain composition of the present invention. In the above, the rare earth oxide (R ₂ O ₃ ) is composed of didymium oxide {(Nd + Pr) ₂ O ₃ }.

Further, in the third embodiment of the dielectric porcelain composition of the present invention, one of BaO in the first main component porcelain composition is used instead of the first main component porcelain composition. Part is replaced by SrO, the general formula is (a-e) BaO-
_{eSrO-bR 2 O 3 -cBi 2} O 3 -dTiO 2 ( where, e = 0.1 to 3.5 mol%) having a second principal component ceramic composition represented by. Where a + b + c + d
= 100 mol%, a, b, c and d are the same as in the first main component porcelain composition, and the amount of the additive is also the same as in the above-mentioned dielectric porcelain composition.

As described above, in order to manufacture the dielectric ceramic composition according to the embodiment of the present invention, first, BaCO ₃ or a part of which is replaced with SrO, R ₂ O ₃ ,
Nd ₂ O ₃ or (Nd + Pr) ₂ O ₃ (didymium oxide),
The raw material powders of Bi ₂ O ₃ and TiO ₂ are weighed according to each composition, and then wet mixed with pure water using a resin ball mill with zirconia balls to obtain a mixture.
Next, after drying this mixture, it is calcined in the atmosphere,
Obtain a calcined product. Next, the GeO ₂ powder is weighed so as to have a composition ratio, added to the calcined product, and wet-ground (mixed) with the above ball mill. This is molded into a disk shape and sintered in the atmosphere to obtain a dielectric ceramic material.

In the embodiment of the present invention, GeO ₂ is added to the first or second main component porcelain composition in an amount of 0.0
By adding 5 to 8.0% by weight, the sintering temperature of 1300 to 1500 ° C., which was necessary to obtain the optimum dielectric constant ε _r , can be lowered to 1000 to 1200 ° C., and Q × The f value is large, and the temperature coefficient τ of the resonance frequency is
_A dielectric ceramic composition having an _f close to zero was obtained.

[0024]

Embodiments of the present invention will be described below.

(Example 1) First, BaCO ₃ , Nd ₂ O
Each powder of ₃ , Bi ₂ O ₃ and TiO ₂ was weighed according to each composition, and then wet mixed with pure water using a resin ball mill with zirconia balls 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 GeO ₂ powder was weighed so that the proportions shown in Table 4 were obtained, respectively, and then 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 975 to 1375 ° C. for about 2 hours to obtain a dielectric ceramic material. The composition in Table _{4, aBaO-bNd 2 O 3} -cBi 2 O 3 -dT
It is expressed as iO ₂ (mol%, a + b + c + d = 100).

[0026]

[Table 4]

Next, with respect to the dielectric porcelain having each composition, the dielectric constant ε _r , Q × f value, and temperature coefficient τ _f of resonance frequency were measured by the dielectric resonator method. Temperature coefficient of resonance frequency τ _f
Was calculated from the difference of the resonance frequency f in the temperature range of +20 to + 60 ° C. by the following formula 1.

[0028]

(Equation 1)

The measurement results are shown in Table 4 above. The resonance frequency was 2.5 to 4.0 GHz.

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 that shown in Example 1. Next, GeO ₂ powders were weighed so that the ratios were as shown in Table 5 below, added to the calcined product, wet-ground (mixed) with the same ball mill as shown in Example 1, and then molded and baked. Then, the dielectric porcelain having the composition shown in Table 2 was obtained. The composition in Table 5 below is aBaO-b.
It is expressed as (Nd + Pr) ₂ O ₃ -cBi ₂ O ₃ -dTiO ₂ (mol%, a + b + c + d = 100 mol%).

[0031]

[Table 5]

Next, the same measurements as those shown in Example 1 were carried out on the dielectric ceramics having the respective compositions, and the measurement results shown in Table 5 were obtained. The analysis values of didymium oxide are as shown in Table 6, and the weighing was performed by converting Pr ₂ O ₃ into 1 mol.

[0033]

[Table 6]

(Example 3) BaCO ₃ , SrO, Nd ₂
Powders of O ₃ , Bi ₂ O ₃ and TiO ₂ were weighed according to each composition, and a calcined product was obtained by the same method as that shown in Example 1. Next, the GeO ₂ powder was weighed so that the proportions shown in Table 2 were obtained, added to the calcined product, and wet-ground (mixed) with the same ball mill as shown in Example 1, followed by molding and sintering. Then, the dielectric porcelain having the composition shown in Table 7 was obtained. In Table 7, the composition is (a-e) BaO-eSrO-
_{bNd 2 O 3 -cBi 2 O 3} -dTiO 2 ( mole%, a
+ B + c + d = 100 mol%).

[0035]

[Table 7]

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.

(Example 4) BaCO ₃ , SrO, (Nd
+ Pr) ₂ O ₃ (didymium oxide), Bi ₂ O ₃ , TiO ₂
Each powder was weighed according to each composition, and a calcined product was obtained by the same method as described in Example 1. Next, GeO ₂ powders were weighed so that the proportions shown in Table 2 were obtained respectively, added to the calcined product, wet-ground (mixed) with a ball mill similar to that shown in Example 1, molded, and sintered. A dielectric ceramic having the composition shown in Table 4 was obtained. The composition in Table 8 below is (a-e).
BaO-eSrO-b (Nd + Pr) 2 O 3 -cBi 2
It is expressed as O ₃ -dTiO ₂ (mol%, a + b + c + d = 100 mol%).

[0038]

[Table 8]

Next, the dielectric ceramics of each composition were measured in the same manner as in Example 1, and the measurement results shown in Table 8 were obtained. The analysis values of didymium oxide are as shown in Table 5 above, and the weighing was performed by converting Pr ₂ O ₃ into 1 mol.

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 0.05 to 8.0 wt% of GeO ₂ 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 the Q × f value is large. Is large, the temperature coefficient τ _f of the resonance frequency is close to zero, and 1000 to 12
It is possible to obtain a dielectric ceramic that can be sintered at a low temperature of 00 ° C.

On the other hand, in comparative examples other than the examples of the present invention, if the addition amount is less than 0.05% by weight, the effect of the addition cannot be obtained and the sintering temperature exceeds 1200 ° C. Further, when the added amount exceeds 8.0% by weight, the dielectric constant ε _r and Q × f value remarkably decrease.

[0042]

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

[Brief description of the drawings]

FIG. 1 is a ternary system phase diagram showing a composition range of a first main component porcelain composition of a dielectric porcelain composition according to an embodiment of the present invention.

Claims (4)

[Claims] 1. At least one of rare earth oxides containing BaO and Nd as essential components (R ₂ O ₃ ), Bi ₂ O.
₃ and TiO ₂ as main components, and the general formula is 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%), and a, (b + c) and d connect the four points P, Q, R and S in the following Table 1 in the ternary system phase diagram. G as an additive to the first main component porcelain composition within the range
A dielectric ceramic composition comprising eO ₂ in a proportion of 0.05 to 8.0% by weight based on the total amount. [Table 1] 2. The dielectric ceramic composition according to claim 1, wherein the R ₂ O ₃ is Nd ₂ O ₃ . 3. The dielectric ceramic composition according to claim 1, wherein the rare earth oxide (R ₂ O ₃ ) is didymium oxide {(N
d + Pr) ₂ O ₃ }. 4. The dielectric porcelain composition according to claim 1, wherein one of BaO in the first main component porcelain composition is used in place of the first main component porcelain composition. Part is replaced by SrO, the general formula is (a-e) BaO-e
_{SrO-bR 2 O 3 -cBi 2} O 3 -dTiO 2 ( where, e = 0.1 to 3.5 mol%) dielectric ceramic and having a second principal component ceramic composition represented by Composition.