JPH09165258A - Production of dielectric porcelain composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a dielectric porcelain composition stably having characteristics comprising a large dielectric constant εr , a large Q×f value and a resonance frequency temperature coefficient extremely near to zero by subjecting a sintered product having a specific composition of BaO-Sm2 O3 -Bi2 O3 - TiO2 system to a hot hydrostatic pressure press treatment under specific conditions. SOLUTION: This method for producing a dielectric porcelain composition represented by a general formula: aBaO-bSm2 O3 -cBi2 O3 -dTiO2 [the units of (a), (b), (c) and (d) are mol.%; 13.6<=a<=18.6, 14.7<=(b+c)<=19.2, 64.5<=d<=69.2, 0.70<=c<=9.4; the total amount of (a) to (d) is 100mol.%], wherein the sintered dielectric porcelain is subjected to a hot hydrostatic press treatment under conditions comprising a temperature of 1,000-1,300 deg.C, a pressure of 500-1,500 atm and a time of 1-10hr.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a dielectric ceramic composition used for a dielectric resonator or the like which is mainly used for communication equipment or broadcasting equipment for microwave band.

[0002]

2. Description of the Related Art In recent years, due to advances in communication technology, mobile communication systems such as car phones and mobile phones such as PHS whose services have started, GPS (Global Positioning System)
m) is spreading rapidly. Therefore, the frequency band used for communication has expanded, and communication in the microwave band has become popular.

In the old days, a cavity resonator, an antenna and the like were used in the circuit used in this microwave band.
However, since these parts are about the same size as the wavelength of microwaves, they are used in automobile phones, mobile phones, small G
It has been difficult to manufacture small parts that can be applied to PS devices and the like.

On the other hand, in recent years, by using a dielectric resonator in a microwave filter or a frequency stabilizing circuit of an oscillator, miniaturization of circuit parts has been actively performed and is becoming popular.

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. The magnitude of the dielectric loss tan δ in the microwave band is generally expressed in the form of Q × f (f is the resonance frequency at that time). Therefore, the expression Q × f will be used below.

Further, the temperature compensating capacitors which have been used mainly for coils, ICs, crystal oscillators, etc., have been increasing in demand recently as bypass capacitors for digital circuits of mobile communication devices. doing.

So far, Ba (Z) has been used as a dielectric ceramic composition for microwaves or capacitors.
n _1/3 , Ta _2/3 ) O ₃ system, BaO—TiO ₂ system, ZrO ₂ —
SnO ₂ -TiO ₂ system, BaO- rare earth oxide -TiO ₂
Materials such as those based on (Pb, Ca) ZrO ₃ system are known.

However, the materials having the compositions disclosed so far tended to have a smaller Q × f as the ε _r increased in the microwave band.

In order to solve the drawback, the present inventors have proposed a composition having a sufficiently large unloaded Q, a dielectric constant ε _r > 110, and a temperature coefficient τ _f that is sufficiently small in practical use.
The _{BaO-La 2 O 3 -Sm 2} O 3 -Bi 2 O 3 -TiO 2 was proposed in Japanese Patent Application No. 5-275360.

[0010]

However, these dielectric porcelain compositions, when the average particle size of the calcined product becomes 1.20 μm or more, depending on the composition, particularly the amount of Bi ₂ O ₃ ,
There is a problem that ε _r and Q × f are deteriorated without forming a dense sintered body. Further, such a sintered body has many voids, which makes it easy to absorb water, weakens mechanical strength, and the like, which causes a problem that reliability is greatly deteriorated.

Further, when wet calcining the calcined product with a ball mill using zirconia balls for a long time, the average particle size of the calcined product can be made smaller than 1.20 μm and a dense sintered body can be formed, but zirconia is mixed. To obtain ε _r , Q
There is a problem that xf and τ _f deteriorate.

Therefore, the technical problem of the present invention is that the dielectric constant ε
_r , Q × f value is large, and the temperature coefficient of resonance frequency τ _f
It is an object of the present invention to provide a method for producing a dielectric ceramic composition, which can stably obtain characteristics as close to zero as possible.

[0013]

In order to solve the above-mentioned problems, the inventor of the present invention has developed a sintered body at a temperature of 1000 to 1300 ° C. and a pressure of 500 to 1500 atm for 1 to 10 hours.
By the IP treatment, the average particle size of the calcined product is 1.20.
It was found that a dielectric ceramic composition having a large dielectric constant ε _r Q × f value and a temperature coefficient τ _{f of} resonance frequency close to zero can be obtained even when the thickness is μm or more.

That is, according to the present invention, the general formula is aBa
_{O-bSm 2 O 3 -cBi 2} O 3 -dTiO 2 ( However,
The units of a, b, c, and d are mol%), and 13.6 ≦ a
≤18.6, 14.7≤ (b + c) ≤19.2, 64.5≤
d ≦ 69.2, 0.70 ≦ c ≦ 9.4, and a
In the method for producing a dielectric ceramic composition represented by + b + c + d = 100 mol%, the dielectric ceramic obtained by sintering is heated at a temperature of 1000 to 1300 ° C. and a pressure of 500 to 1500 atm for 1 to 10 hours, A method for producing a dielectric ceramic composition characterized by HIP treatment is obtained.

According to the present invention, the general formula is aBaO.
_{-BSm 2 O 3 -cBi 2 O 3} -eLa 2 O 3 -dTiO
₂ (However, the units of a, b, c, d, and e are mol%)
, 13.6 ≦ a ≦ 18.6, 14.7 ≦ (b + c + e)
≤19.2, 64.5 ≤ d ≤ 69.2, 0.70 ≤ c ≤ 9.
4, within the range of 0.20 ≦ e ≦ 6.0, a + b + c +
In the method for producing a dielectric ceramic composition represented by e + d = 100 mol%, 100% of the dielectric ceramic obtained by sintering is used.
The method for producing a dielectric ceramic composition is characterized in that HIP treatment is carried out at a temperature of 0 to 1300 ° C. and a pressure of 500 to 1500 atm for 1 to 10 hours.

According to the present invention, the general formula is aBaO.
_{-FSrO-bSm 2 O 3 -cBi 2} O 3 -dTiO 2 ( however, a, b, c, d, and the unit of f is mol%), the 1
3.6 ≦ (a + f) ≦ 18.6, 14.7 ≦ (b + c) ≦
19.2, 64.5 ≤ d ≤ 69.2, 0.10 ≤ f ≤ 5.
5, 0.70 ≦ c ≦ 9.4, a + f + b + c + d = 100
In the method for producing a dielectric ceramic composition represented by mol%, the dielectric ceramic obtained by sintering is 1000 to 1300.
1 to 10 at a temperature of ℃ and a pressure of 500 to 1500 atm.
A method for producing a dielectric ceramic composition characterized by performing HIP treatment for a time is obtained.

According to the present invention, the general formula is aBaO.
_{-FSrO-bSm 2 O 3 -cBi 2} O 3 -eLa 2 O 3 -d
TiO ₂ (however, the units of a, b, c, d, e, and f are mol%), and 13.6 ≦ (a + f) ≦ 18.6, 14.
7 ≦ (b + c + e) ≦ 19.2, 64.5 ≦ d ≦ 69.
2, 0.10 ≤ f ≤ 5.5, 0.70 ≤ c ≤ 9.4, 0.2
Within the range of 0 ≦ e ≦ 6.0, a + f + b + c + e +
In the method for producing a dielectric ceramic composition represented by d = 100 mol%, the dielectric ceramic obtained by sintering is 1000 to
At a temperature of 1300 ° C. and a pressure of 500 to 1500 atm,
A method for producing a dielectric ceramic composition is obtained, which comprises performing HIP treatment for 1 to 10 hours.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The details of the embodiments of the present invention will be described below based on Examples.

Example 1 First, BaCO ₃ , Sm
Each powder of ₂ O ₃ , Bi ₂ O ₃ and TiO ₂ was weighed according to each composition, and then pure water was wet mixed with a zirconia ball in a resin ball mill for 20 hours to obtain a mixture.

Next, this mixture was dried and then calcined in the atmosphere at a temperature of 1200 ° C. for about 4 hours to obtain a calcined product. Next, it was wet-milled for 20 hours 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 1250 to 1375 ° C. for about 2 hours to obtain a sintered body.

Next, this sintered body was subjected to HIP treatment for 2 hours at a temperature of 1000 to 1300 ° C. and a pressure of 1000 atm in an argon gas atmosphere. Further, the HIP-treated sintered body was heat-treated at a temperature of 1200 ° C. in the atmosphere to obtain a dielectric ceramic having the composition shown in Table 1.

[0023]

[Table 1]

The composition is aBaO-bSm ₂ O ₃ -c.
It is expressed as Bi ₂ O ₃ -dTiO ₂ (a + b + c + d = 100 mol%).

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.

The temperature coefficient τ _f of the resonance frequency is +20 to +
It was calculated from the difference of the resonance frequency f in the temperature range of 60 ° C. by the following formula. τ _f = [f (60 ° C.) − f (20 ° C.)] / [40 × f
(20 ° C.)] The resonance frequency was 2.2 to 3.2 GHz.

Next, the average particle size of the calcined product was measured with a laser beam particle size analyzer. The measurement results are shown in Table 1.

(Example 2) BaCO ₃ , Sm ₂ O ₃ , Bi ₂
Powders of O ₃ , La ₂ O ₃ , and TiO ₂ were weighed according to each composition, and a sintered body was obtained by the same method as shown in Example 1.
Then, this sintered body is heated to 1000 in an argon gas atmosphere.
HIP treatment was performed at a temperature of ˜1300 ° C. and a pressure of 1000 atm for 2 hours. Further, the HIP-treated sintered body was heat-treated in the atmosphere at a temperature of 1200 ° C. to obtain a dielectric ceramic having a composition shown in Table 2.

[0029]

[Table 2]

The composition is aBaO-bSm ₂ O ₃ -c.
_{Bi 2 O 3 -eLa 2 O 3} -dTiO 2 (a + b + e + d =
100 mol%).

Next, the characteristics of the dielectric porcelain of each composition and the average particle size of the calcined product were measured in the same manner as in Example 1. Table 2 shows the measurement results.

Example 3 BaCO ₃ , SrO, Sm ₂ O
Powders of ₃ , ₃ , Bi ₂ O ₃ and TiO ₂ were weighed according to each composition, and a sintered body was obtained by the same method as shown in Example 1.
Then, this sintered body is heated to 1000 in an argon gas atmosphere.
HIP treatment was performed at a temperature of ˜1300 ° C. and a pressure of 1000 atm for 2 hours. Further, the HIP-treated sintered body was heat-treated in the atmosphere at a temperature of 1200 ° C. to obtain a dielectric ceramic having a composition shown in Table 3.

[0033]

[Table 3]

The composition is aBaO-fSrO-bS.
_{m 2 O 3 -cBi 2 O 3} -dTiO 2 (a + f + b + c + d
= 100 mol%).

Next, the characteristics of the dielectric porcelain of each composition and the average particle size of the calcined material were measured in the same manner as in Example 1. Table 3 shows the measurement results.

Example 4 BaCO ₃ , SrO, Sm ₂ O
Each powder of ₃ , Bi ₂ O ₃ , La ₂ O ₃ , and TiO ₂ was weighed according to each composition, and a sintered body was obtained by the same method as shown in Example 1. Next, this sintered body was HIP-treated for 2 hours at a pressure of 1000 atm at a temperature of 1000 to 1300 ° C. in an argon gas atmosphere. Further, this HIP-treated sintered body was heat-treated in the atmosphere at a temperature of 1200 ° C.
A dielectric ceramic having the composition shown in was obtained.

[0037]

[Table 4]

The composition is aBaO-fSrO-bS.
_{m 2 O 3 -cBi 2 O 3} -eLa 2 O 3 -dTiO 2 (a + f
+ B + c + e + d = 100 mol%).

Next, the characteristics of the dielectric porcelain of each composition and the average particle diameter of the calcined material were measured in the same manner as in Example 1. Table 4 shows the measurement results.

As is clear from Tables 1 to 4 above, the dielectric ceramics obtained by sintering are HI at a temperature of 1000 to 1300 ° C. and a pressure of 500 to 1500 atm for 1 to 10 hours.
By P treatment, the average particle size of the calcined product is 1.20μ
Even if it is more than m, the permittivity ε _r and Q × f value are large, and the temperature coefficient τ _{f of the} resonance frequency is close to zero.

On the other hand, in the comparative examples other than the sample of the present invention, the sample not subjected to the HIP treatment and the HIP temperature of 90%.
If the temperature is lower than 0 ° C, a dense sintered body cannot be obtained,
Only low values can be obtained for both ε _r and Q × f. Further, when the HIP temperature exceeds 1300 ° C., Q × f deteriorates and ε _r also deteriorates slightly.

[0042]

As described above, according to the present invention,
Sinter the sintered body at a temperature of 1000 to 1300 ° C. for 500 to 15
By HIPing at a pressure of 00 atm for 1 to 10 hours, even if the average particle size of the calcined product is 1.20 μm or more, the dielectric constant ε _r and Q × f value are large, and the temperature coefficient of the resonance frequency is high. A method for producing a dielectric ceramic composition having τ _f close to zero can be obtained.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kokuni Takahata 6-7-1, Koriyama, Taichiro-ku, Sendai-shi, Miyagi Tokin Co., Ltd.

Claims (4)

[Claims] 1. The general formula is aBaO-bSm ₂ O ₃ -cB.
i ₂ O ₃ -dTiO ₂ (however, the units of a, b, c, and d are mol%), and 13.6 ≦ a ≦ 18.6, 14.7 ≦
(B + c) ≦ 19.2, 64.5 ≦ d ≦ 69.2, 0.70
Within the range of ≦ c ≦ 9.4, a + b + c + d = 100
In the method for producing a dielectric ceramic composition represented by mol%, the dielectric ceramic obtained by sintering is 1000 to 1300.
1 to 10 at a temperature of ℃ and a pressure of 500 to 1500 atm.
Time, Hot Isostatic Press (hereinafter H
A process for producing a dielectric ceramic composition, characterized by performing a treatment. 2. The general formula is aBaO-bSm ₂ O ₃ -cB.
_{i 2 O 3 -eLa 2 O 3} -dTiO 2 ( however, a, b,
The units of c, d, and e are mol%), and 13.6 ≦ a ≦ 1
8.6, 14.7 ≦ (b + c + e) ≦ 19.2, 64.5 ≦
d ≦ 69.2, 0.70 ≦ c ≦ 9.4, 0.20 ≦ e ≦ 6.
In the range of 0, a + b + c + e + d = 100 mol%
In the method for producing a dielectric porcelain composition represented by, the dielectric porcelain obtained by sintering is HI at a temperature of 1000 to 1300 ° C. and a pressure of 500 to 1500 atm for 1 to 10 hours.
A method for producing a dielectric ceramic composition, which comprises performing P treatment. 3. The general formula is aBaO-fSrO-bSm.
₂ O ₃ -cBi ₂ O ₃ -dTiO ₂ (provided that a, b, c,
The units of d and f are mol%), and 13.6 ≦ (a + f)
≤18.6, 14.7≤ (b + c) ≤19.2, 64.5≤
d ≦ 69.2, 0.10 ≦ f ≦ 5.5, 0.70 ≦ c ≦ 9.
4, in the method for producing a dielectric ceramic composition represented by a + f + b + c + d = 100 mol%, the dielectric ceramic obtained by sintering is heated at a temperature of 1000 to 1300 ° C. to 500 to 1
A method for producing a dielectric ceramic composition, which comprises HIPing at a pressure of 500 atm for 1 to 10 hours. 4. The general formula is aBaO-fSrO-bSm.
₂ O ₃ -cBi ₂ O ₃ -eLa ₂ O ₃ -dTiO ₂ (however,
units of a, b, c, d, e, and f are mol%), and 1
3.6 ≦ (a + f) ≦ 18.6, 14.7 ≦ (b + c +
e) ≤ 19.2, 64.5 ≤ d ≤ 69.2, 0.10 ≤ f ≤
5.5, 0.70 ≤ c ≤ 9.4, 0.20 ≤ e ≤ 6.0, within the range of a + f + b + c + e + d = 100 mol% The obtained dielectric porcelain was HI at a temperature of 1000 to 1300 ° C. and a pressure of 500 to 1500 atm for 1 to 10 hours.
A method for producing a dielectric ceramic composition, which comprises performing P treatment.