JPH07309659A - Dielectric porcelain material - Google Patents

Abstract

PURPOSE:To provide a dielectric porcelain material which has a large dielectric constant epsilonr, the temp. coefft. tauf of a resonance frequency as approximate as to zero, a large QXf value and permits simultaneous sintering even if Au, Ag, Cu, and their alloys, etc., having low m.p. are used for internal electrode materials. CONSTITUTION:This dielectric porcelain material consists of an essential component having the chemical compsn. expressed by general formula, a(Ba1-xPbx)-O-b(La1-yGdy)2O3-cTiO2 (where, a=11.7 21.7mol%, b=11.7 to 21.7mol%, a+b+c=100 mol%, 0.01<=x<=0.65, 0.01<=y<=0.65) and the additives added to this essential component. The additive consist of 0.2 to 4.0wt.% SiO2, 0.2 to 3.0wt.% B2O3 and 0.5 to 4.0wt.% PbO with on the total weight of the dielectric porcelain material.

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 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.

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, B has been used as a microwave dielectric material.
aO-TiO ₂ system, BaO · 4TiO ₂ · 0.1W
O ₃ , Ba (Zn _1/3 Ta _2/3 ) O ₃ , (Zr _0.8 Sn
_0.2 ) Compositions such as TiO ₄ are known, but in these systems, high Q × f value, temperature coefficient of resonance frequency τ _f ≈ ± 0 pp
Although m / ° C was obtained, the permittivity ε _r was only about 40 at most, and it could not contribute to the miniaturization of parts in the low frequency band.

Further, a rare earth oxide is added to the above BaO—TiO ₂ system, and the Ba site is replaced by Pb or Sr. (Ba, Pb) O—Nd ₂ O ₃ —TiO ₂ system, (B
a, Sr) O—Sm ₂ O ₃ —TiO ₂ system, dielectric constant ε
It is known that _r = 70 to 100 can be obtained, but it has a drawback that the Q value in the microwave band is inferior to that of the above system. In addition, the dielectric material containing a rare earth oxide as a main component as described above has a large demand for N as a rare earth magnet material.
Since a large amount of d ₂ O ₃ and Sm ₂ O ₃ are used, it cannot be said that the rare earth elements are effectively used.

[0008] The present inventors, as a additive material BaO-TiO ₂ system, using La ₂ O ₃ that is the only without oversupply applications such as glass additives, precious Nd ₂ O
_{No 3} or Sm ₂ O ₃ (Ba, Pb)-(La,
A Gd) ₂ Ti ₄ O ₁₂ based dielectric material has been found. (See Japanese Patent Application No. 5-287713)

[0009]

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, Au, Ag, and C, which have good conductivity, are generally used in the electrode part of the device used in the microwave band.
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 simultaneously sintered.

However, in order to obtain a sufficient sintering density and a large dielectric constant ε _r with the above-mentioned conventionally known dielectric material, it is necessary to sinter at 1300 to 1500 ° C. There is a problem that Au, Ag, Cu, etc. cannot be used.

Therefore, the technical problem of the present invention is that the dielectric constant ε
Au, A 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
Another object of the present invention is to provide a dielectric ceramic material that can be co-sintered even when g, Cu, or an alloy thereof is used as an internal electrode material.

[0013]

In order to solve the above-mentioned problems, the inventor of the present invention added SiO ₂ , B ₂ O ₃ , and PbO to increase the dielectric constant ε _{r and} increase the temperature at the resonance frequency. A dielectric ceramic material having a coefficient τ _f close to zero, a large Q × f value, and a low melting point, such as Au, Ag, Cu, and their alloys, which can be simultaneously sintered even when used as the internal electrode material, is obtained. I found that

That is, according to the present invention, the chemical composition is represented by the general formula: a (Ba _1-x Pb _x ) Ob (La _1-y Gd _y ) ₂
O ₃ -cTiO ₂ (where a = 11.7 to 21.7 mol%, b = 11.7 to 21.7 mol%, a + b + c = 1
00 mol%, 0.01 ≦ x ≦ 0.65, 0.01 ≦ y ≦
0.65), and a dielectric porcelain material comprising a main component and an additive added to the main component, wherein the additive is 0.2 to the total amount of the dielectric porcelain material. 4.
0 wt% SiO ₂ and 0.2-3.0 wt% B ₂ O ₃
And a dielectric ceramic material characterized by comprising 0.5 to 4.0 wt% of PbO.

[0015]

As described above, SiO ₂ is 0.2 to 4.0% by weight, B ₂ O ₃ is 0.2 to 3.0% by weight, and PbO is 0.5% by weight.
˜4.0% by weight, the sintering temperature of 1300-1500 ° C., which was necessary to obtain the optimum dielectric constant ε _r ,
It can be lowered to 1000 to 1100 ° C. Thereby, the dielectric material and the internal electrode material can be sintered at the same time.

[0016]

EXAMPLES The present invention will be described in detail below based on examples.

First, a method for manufacturing a dielectric ceramic material will be described.

BaCO ₃ , PbO, La ₂ O ₃ , Gd ₂
O ₃ and TiO ₂ powders were weighed so as to have the ratios shown in Table 1, and were then wet mixed with pure water using a resin ball mill with zirconia balls to obtain a mixture. next,
After this mixture was dried, it was calcined in the atmosphere at a temperature of 1050 ° C. for about 4 hours to obtain a calcined product. Next, SiO ₂ ,
The powders of B ₂ O ₃ and PbO were weighed so as to have the ratios shown in Table 1 below, added to the calcined product, and wet-ground (mixed) with the above ball mill. This is molded into a disk shape with a diameter of 15 mm and a thickness of about 6 mm, and 1000-1
Dielectric ceramic materials (Samples 1 to 35) were obtained by sintering at a temperature of 375 ° C. for about 1 hour.

Next, the dielectric properties of this dielectric ceramic material were measured.

With respect to the dielectric ceramics having these compositions, by the dielectric resonator method, the dielectric constant ε _r , Q × f value, and −25.
The temperature coefficient τ _f of the resonance frequency at -80 ° C was measured. The results are shown in Table 2 below. In addition, the following Table 1,
And in Table 2, those with * in the column of sample number are
It is a comparative example other than the sample which concerns on the Example of this invention. Also,
The resonance frequency was 2.9 to 3.5 GHz.

[0021]

[Table 1]

[Table 2] As is clear from Table 2 above, (Ba _1-x Pb _x ) O-
The _{(La 1-y Gd y)} 2 O 3 -TiO 2 based materials, SiO
₂ to 0.2 to 4.0% by weight, B ₂ O ₃ to 0.2 to 3.0
By adding 0.5% by weight of PbO and 0.5-4.0% by weight of PbO, the dielectric constant ε _r is large, the Q × f value is large, the temperature coefficient τ _f of the resonance frequency is close to zero, and moreover 1000-110.
It is possible to obtain a dielectric ceramic that can be sintered at a low temperature of 0 ° C.

On the other hand, the samples (1, 4,
5,8,9,12-14,17-19,25,26,2
8, 30, 33), the addition amount is 0.2% by weight for SiO ₂ , 0.2% by weight for B ₂ O ₃ , and P.
When bO is smaller than 0.5% by weight, the effect of addition cannot be obtained, and the sintering temperature exceeds 1100 ° C. In addition, the addition amount is 4.0% by weight of SiO ₂ and B, respectively.
It has been found that the dielectric constant ε _r and Q × f value are remarkably lowered when the content of ₂ O ₃ exceeds 3.0 wt% and PbO of 4.0 wt%.

[0023]

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
Even if g, Cu, or an alloy thereof is used as the internal electrode material, a dielectric ceramic material that can be co-sintered can be obtained.

Claims (1)

[Claims] 1. The chemical composition is represented by the general formula: a (Ba _1-x P
_{b x) O-b (La} 1-y Gd y) 2 O 3 -cTiO
₂ (However, a = 11.7 to 21.7 mol%, b = 1
1.7 to 21.7 mol%, a + b + c = 100 mol%,
0.01 ≤ x ≤ 0.65, 0.01 ≤ y ≤ 0.65), and a dielectric ceramic material comprising an additive added to the main component, wherein the additive is 0.2 to 4.0% by weight of SiO _{2 with} respect to the total amount of the dielectric ceramic material
And 0.2-3.0% by weight of B ₂ O ₃ and 0.5-4.0% by weight of PbO.