JPH0845345A - Dielectric porcelain material - Google Patents

Abstract

(57) [Abstract] [Purpose] Ag, Ag-Pd alloy, Cu, etc. with a large permittivity ε _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. To provide a dielectric ceramic material having a low sintering temperature, which enables simultaneous sintering as an internal electrode. [Configuration] The dielectric ceramic material of 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 = 11.1.
7 to 21.7 mol%, a + b + c = 100 mol%, and x and y are 0.01 ≦ x ≦ 0.65, 0.01 ≦
y is a number within the range of 0.65), the main component having a chemical composition represented by
~ 4.0 wt% SiO ₂ and 0.3-4.0 wt% F
e ₂ O ₃ was added.

Description

Detailed Description of the Invention

[0001]

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

[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, it is impossible to miniaturize the parts applicable to automobile telephones, mobile phones, small GPS devices and the like.

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

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 _f 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 (expressed in the form of Q × f. F is a resonance frequency) is large.

Conventionally, Ba has been used as a microwave dielectric material.
O-TiO ₂ system, BaO.4TiO ₂ .0.1WO ₃ ,
Ba (Zn _1/3 Ta _2/3 ) O ₃ , (Zr _4/5 Sn _1/5 ).
Although compositions such as TiO ₄ are known, although high Q × f value and temperature coefficient τ _f ± 0 ppm / ° C of resonance frequency can be obtained with these systems, the dielectric constant ε _r is only about 40 at most,
In the low frequency band, it could not contribute to miniaturization of parts.

A rare earth oxide is added to the above BaO--TiO ₂ system, and the Ba site is replaced with 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 = 70-100 is obtained.

Further, the present inventors have found that (Ba, Pb) O-
The (La, Gd) ₂ O ₃ —TiO ₂ based dielectric material is 90-
It has been found that it has a dielectric constant ε _{r of} about 100 and is proposed in Japanese Patent Application No. 5-28713.

[0010]

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. LC above
In order to obtain an element or the like, it is necessary that a relatively inexpensive electrode material such as Ag, Ag-Pd alloy, or Cu 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., which is a laminated ceramic circuit component. In order to obtain the above, there was a problem that expensive Pt and Pt-based alloys had to be used as the internal electrode material.

Therefore, the technical problem of the present invention is that the dielectric constant ε
Ag, 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 having a low sintering temperature that enables simultaneous sintering of g-Pd alloy, Cu, etc. as internal electrodes.

[0013]

In order to solve the above problems, the present inventor has added SiO ₂ and Fe ₂ O ₃ to increase the dielectric constant ε _{r and} the temperature coefficient τ of the resonance frequency. Dielectric porcelain material with low sintering temperature that can be co-sintered even if _f, which is close to zero, has a large Q × f value, is inexpensive, and has a low melting point, such as Ag, Ag-Pd alloy, Cu, etc. It was found that

That is, according to the present invention, the general formula a (Ba
_{1-x Pb x) O-} b (La 1-y Gd y) 2 O 3 -cTi
O ₂ (however, a = 11.7 to 21.7 mol%, b = 1
1.7 to 21.7 mol%, a + b + c = 100 mol%, and x and y are 0.01 ≦ x ≦ 0.65, 0.01
≦ y ≦ 0.65), with 0.3 to 4.0% by weight of SiO ₂ and 0.3 to 4.0% by weight as an additive, based on the main component having a chemical composition. And Fe ₂ O ₃ are added to obtain a dielectric ceramic material.

[0015]

[Function] As described above, SiO _{2 is} added to the above main component.
Of 0.3 to 4.0 wt% and Fe ₂ O ₃ of 0.3 to 4.0
Addition of 100% by weight makes the sintering temperature of 1300 to 1500 ° C. required to obtain the optimum dielectric constant ε _r 100%.
It can be lowered to 0 to 1100 ° C. As a result, the dielectric material and the low melting point and inexpensive electrode material can be simultaneously sintered.

[0016]

EXAMPLES The details of the present invention will be described below based on examples.

First, a method of 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 below, and then pure water was used to wet mix with a resin ball mill using zirconia balls to obtain a mixture. Next, after drying this mixture, it is heated to 1050 ° C in the atmosphere.
It was calcined at the temperature of about 4 hours to obtain a calcined product. Next, SiO
Each of the powders of ₂ and Fe ₂ O ₃ was weighed so as to have the ratio 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 the pressure is 1000 to 13 in the atmosphere.
A dielectric ceramic material was obtained by sintering at a temperature of 75 ° C. for about 1 hour.

Next, the measurement of the dielectric properties of this dielectric ceramic material will be described.

With respect to the dielectric porcelain having the above composition, the dielectric constant ε _r , Q × f value, and −25 to 8 were obtained by the dielectric resonator method.
The temperature coefficient τ _f of the resonance frequency at 0 ° C was measured. The results are shown in Table 2 below. In Tables 1 and 2 below, those marked with * in the column of sample number are comparative examples other than the sample of the present invention. The resonance frequency is 2.9.
Was 3.5 GHz.

[0021]

[Table 1]

[0022]

[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 0.3 to 4.0% by weight, and Fe ₂ O ₃ to 0.3 to 4.0%.
By adding 0% by weight, the dielectric constant ε _r becomes large, and Q × f
It is possible to obtain a dielectric ceramic having a large value, a temperature coefficient τ _f of the resonance frequency close to zero, and capable of sintering at a low temperature of 1000 to 1100 ° C.

On the other hand, in the comparative examples having compositions other than the examples of the present invention, when the addition amounts were smaller than 0.3% by weight of SiO _{2 and} 0.3% by weight of Fe ₂ O ₃ , respectively, the effect of the addition was small. It cannot be obtained and the sintering temperature exceeds 1100 ° C. In addition, the addition amount of SiO _{2 is} 4.0% by weight, and F is
e ₂ O _{3 When} it exceeds 4.0% by weight, the dielectric constant ε _r , Q ×
It was found that F was significantly reduced.

[0024]

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

Claims (1)

[Claims] 1. A general formula, a (Ba _1-x Pb _x ) O-b
_{(La 1-y Gd y)} 2 O 3 -cTiO 2 ( where, a = 1
1.7 to 21.7 mol%, b = 11.7 to 21.7 mol%, a + b + c = 100 mol%, and x and y are 0.01 ≦ x ≦ 0.65, 0.01 ≦ y. 0.3 to 4.0% by weight, based on the total amount, as an additive to the main component having a chemical composition represented by ≦ 0.65)
SiO ₂ and 0.3 to 4.0% by weight of Fe ₂ O ₃ are added.