JPH05290626A - Manufacture of high frequency dielectric sintered body - Google Patents

Abstract

PURPOSE:To provide a method whereby a high frequency dielectric sintered body such as a BMT sintered body can easily be manufactured in a firm state and at low cost without sacrifying its excellent characteristics. CONSTITUTION:In a method for manufacturing a high frequency dielectric sintered body wherein a temporary sintered substance represented as Ba3MgTa2 O9 or Ba3ZnTa2O9 is baked and sintered, the temporary sintered substance is baked with either MgTa3O6, BaMgO2 or BaZnO2 added thereto.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a high frequency dielectric sintered body used for a high frequency dielectric resonator or the like.

[0002]

2. Description of the Related Art A dielectric material having a high dielectric constant and a high Q value in a microwave region of 1 GHz or more is called a high frequency dielectric, and researches for improving the performance of this high frequency dielectric are actively conducted. .. As a result, a high frequency dielectric having excellent characteristics has been found.

Among these, the (ceramic) high frequency dielectric sintered body having a perovskite type crystal structure represented by the composition formula of A ₃ BC ₂ O ₉ is an excellent high frequency dielectric and has already been put to practical use. Some are. Specifically, as a high frequency dielectric sintered body, Ba ₃ MgTa _{2 is used.}
O ₉ (BMT) sintered body, Ba ₃ ZnTa ₂ O ₉ (BZ
T) Sintered bodies are attracting attention as promising ones. Hereinafter, a BMT sintered body will be described as an example among these sintered bodies.

The BMT sintered body is obtained by shaping powder of a calcined material represented by Ba ₃ MgTa ₂ O ₉ and firing and sintering.

[0005]

However, Ba ₃
The powder of the calcined material represented by MgTa ₂ O ₉ has low sinterability, and it is difficult to obtain a dense BMT sintered body. In the case of a BMT sintered body having a low density, the original high dielectric constant and high Q value characteristics of BMT are not exhibited. Normally, even if the powder of the calcined material of Ba ₃ MgTa ₂ O ₉ is fired at a firing temperature of about 1550 to 1700 ° C. for about 2 hours, the density is at most (theoretical value) 80%. It is not possible to easily manufacture a high density BMT sintered body.

In order to increase the compactness, there is a method of rapidly raising the temperature during firing. However, this method is not suitable for mass production and is not practical because the firing cost is high and it is difficult to reduce the cost of electronic devices (for example, resonators). In addition to this, there is a method of adding a Mn, P, Sn-based sintering aid to the calcined product and firing it. However, although the addition of these sintering aids is certainly effective in terms of improving the sinterability, it is a form in which impurities that are completely different from the aspect of the basic composition of the ceramic are diffused and other characteristics Is not preferable in that it is remarkably excellent.

The above-mentioned circumstances are, of course, similarly applied to the non-sinterable sintered body other than the BMT sintered body. In view of the above circumstances, the present invention provides a sintered body for a high frequency dielectric such as a BMT sintered body in a dense state, without sacrificing the original excellent characteristics, and easily and inexpensively. The challenge is to provide a method that can.

[0008]

In order to solve the above problems, in the method for producing a BMT sintered body according to the invention (first invention) of claim 1, a calcined product represented by Ba ₃ MgTa ₂ O ₉ is obtained. B according to the invention (second invention) according to claim 3, wherein MgTa ₂ O ₆ is added and fired.
In the method for manufacturing the MT sintered body, BaMgO ₂ is added to the calcined product represented by Ba ₃ MgTa ₂ O ₉ and the mixture is fired.

In the method for manufacturing a BZT sintered body according to the fifth aspect of the invention (the third invention), Ba ₃ ZnTa _{2 is used.}
BaZnO ₂ is added to the calcined product represented by O ₉ and the product is fired. Hereinafter, the production of the sintered body for a high frequency dielectric according to the first to third inventions will be described in the order of steps.

First, the first invention will be described. First,
A process for preparing a calcined product represented by Ba ₃ MgTa ₂ O ₉ which is a main material will be described. The starting materials containing the Ba component, the Mg component and the Ta component are weighed according to the stoichiometric ratio of BMT. As the Ba component, for example, BaCO ₃ powder having good reactivity is suitable, but BaO powder may be used. As the Mg component, for example,
MgO powder is used. As the Ta component, for example, T
a ₂ O ₅ powder is used.

First, MgO powder and Ta ₂ O ₅ powder are thoroughly mixed in equimolar amounts with pure water at a weight ratio of 2 to 3 times, and then dried in air. After molding the mixed powder after drying using a mold, the obtained molded body is calcined in air at 1000 to 1300 ° C. for 18 to 30 hours and then cooled, and then pulverized using a vibration mill. Micronize. Subsequently, similarly, molding, firing, and pulverization are repeated twice more. The obtained MgTa ₂ O ₆ powder usually has an average particle size of about 3 μm or less.

Then, BaC is added to the MgTa ₂ O ₆ powder.
The O ₃ powder is thoroughly mixed with pure water in a weight ratio of 1: 3 in a ratio of 1: 3 to 1.5 to 2 times by weight, and then dried in air. After molding the mixed powder after drying using a mold, the obtained molded body is subjected to 3 in air at 800 to 1400 ° C.
It is calcined for about 20 hours and then cooled, and then pulverized into a fine powder using a rotary ball mill. Subsequently, similarly, molding, firing, and pulverization are repeated twice more. The powder of the obtained calcined product usually has an average particle size of about 3 μm or less.

Now, the main material of Ba is₃MgTa₂O
₉The powder of the calcined product will be completed. Other than the above
In addition, as shown in the following (a) to (c), the main material B
a₃MgTa ₂O₉Get the calcined product
Yes. (A) According to the stoichiometric ratio of BMT, Ba component, Mg component and
The starting material containing the Ta component and Ta component is weighed.

As the Ba component, for example, BaCO ₃ powder having good reactivity is suitable, but BaO powder may be used.
As the Mg component, for example, MgO powder is used. T
As the component a, for example, Ta ₂ O ₅ powder is used.
In this case, it is usually preferable to use MgO having a smaller particle size than other powders so that the subsequent reaction proceeds smoothly. (B) The above starting materials were ball milled in a weight ratio of 1.
Mix thoroughly with 5 to 2 times pure water and dry in air. (C) After molding the mixed powder after drying using a mold, the obtained molded body is 3 to 20 in air at 800 to 1400 ° C.
It is calcined for a period of time and then cooled, and then pulverized into a fine powder using a rotary ball mill. The powder of the calcined material of Ba ₃ MgTa ₂ O ₉ usually has an average particle size of about 3 μm or less.

Even in this way, the main material Ba ₃ M
It is possible to make a powder of a calcined product of gTa ₂ O ₉ . Next, the auxiliary material MgTa ₂ O added to the main material is added.
_The process of preparing the powder of ₆ will be described. The starting materials containing the Mg and Ta components are weighed according to the stoichiometric ratio of MgTa ₂ O ₆ .

The Mg component is, for example, MgO powder.
used. As the Ta component, for example, Ta₂O_FivePowder
Is used. MgTa₂O₆The starting material for making the ball mill
After mixing thoroughly with pure water in a weight ratio of 2-3 times,
Dry in air. After molding the mixed powder after drying using a mold,
The formed body is aired at a temperature of about 1000 to 1300 ° C.
After baking for 18 to 30 hours, cool
After that, it is pulverized by a vibration mill to be pulverized. Secondary material
MgTa₂O ₆The average particle size is 3μm or less
Make something of a degree.

That is, the powder of MgTa ₂ O _{6 as} the auxiliary material added to the main material can be obtained by almost the same method as described above. Therefore, when the main material is manufactured in any of above, the materials obtained above can be used as the auxiliary material. Next, steps for obtaining a sintered body using the ceramic powders of the main and auxiliary materials thus obtained will be described.

The weight ratio of the powder of the calcined material represented by Ba ₃ MgTa ₂ O ₉ and the powder of MgTa ₂ O ₆ is 1.5.
Thoroughly mix with about twice the amount of pure water using a ball mill and dry in air. An appropriate amount of organic binder is added to the mixed powder after drying and the mixture is molded with a mold, and then the formed compact is subjected to main firing.
The amount of the organic binder added (solid content conversion) is the mixed powder 1
It is about 0.01 to 0.06 wt% with respect to 00 wt%, and examples of the binder include polyvinyl alcohol.

In the main firing, it is usually 1550 to 1700 ° C.
After heat treatment for 1 to 5 hours, 1300 to
The temperature is lowered to 1450 ° C. and heat treatment for ordering Mg ions and Ta ions is performed for 50 to 120 hours. Regarding the amount of MgTa ₂ O ₆ added, Ba ₃
100% by weight of MgTa ₂ O ₉ calcined product, MgTa ₂ O
The powder of ₆ is usually added in the range of 0.01 to 3% by weight, preferably 1.0% by weight or less. 1.0
If it is less than wt%, when a semiconductor element and an oscillator are combined, the influence on the oscillation frequency change caused by the temperature change is reversed between the semiconductor element and the BMT sintered body in a relatively wide temperature range, and they cancel each other out. As a result, the stability of the oscillation frequency with respect to temperature tends to be improved. The addition amount of MgTa ₂ O ₆ is more preferably in the range of 0.3 wt% or less, and in this range, a very high Q value can be obtained. If it is less than 0.01 wt%, it tends to be difficult to obtain a sufficient addition effect, and if it exceeds 3 wt%, the Q value tends to be insufficient.

The BMT sintered body obtained by the method of the present invention has the following performance and has a very small temperature coefficient τ _f , and is suitable for, for example, a high frequency filter. Relative permittivity: around 24 ... 10 GHz Q value: 35000-50000 ... 10 GHz Temperature coefficient of resonance frequency τ _f ... 0-5 ppm / ° C (3
0-50 ° C) Density: about 99% ... 100% theoretical density of perfect sintered body
Next, the second invention will be described. Ba ₃ MgT which is the main material
The process of preparing the calcined product represented by a ₂ O ₉ can be performed in exactly the same way as in the first aspect of the invention, so the description thereof will be omitted.

BaMgO ₂ as an auxiliary material added to the main material
The production process of the powder is as follows. According to the stoichiometric ratio of BaMgO _2, the Ba component and M
The starting material containing the g component is weighed. As the Ba component,
For example, BaCO ₃ powder having good reactivity is suitable, but BaO powder may be used. As the Mg component, for example, MgO powder is used.

The starting material for preparing BaMgO _{2 is} thoroughly mixed with pure water at a weight ratio of 2-3 times by a ball mill, and then dried in air. After molding the mixed powder after drying using a mold, the obtained molded body is fired in air at a temperature of about 900 to 1300 ° C. for about 18 to 30 hours and then cooled, and then pulverized by a vibration mill. And pulverize. The powder of BaMgO _{2 as} an auxiliary material usually has an average particle size of about 3 μm or less.

Now Ba as a sub-material added to the main material is added.
The powder of MgO ₂ is completed. Next, steps for obtaining a sintered body using the ceramic powders of the main and auxiliary materials thus obtained will be described. The powder of the calcined material represented by Ba ₃ MgTa ₂ O ₉ and the powder of BaMgO ₂ are thoroughly mixed with pure water having a weight ratio of about 1.5 using a ball mill and then dried in air.

An appropriate amount of an organic binder is added to the mixed powder after drying and the mixture is molded with a mold, and then the formed compact is subjected to main firing. Amount of organic binder added (solid content conversion)
Is about 0.01 to 0.06 wt% with respect to 100 wt% of the mixed powder, and examples of the binder include polyvinyl alcohol. In the main firing, it is usually 155
Following heat treatment at 0 to 1700 ° C for about 1 to 5 hours, the temperature is lowered to 1300 to 1450 ° C and then 50 to 12 ° C.
A heat treatment for ordering Mg ions and Ta ions is performed for 0 hours.

Regarding the amount of BaMgO ₂ added, Ba ₃
BaMgO for MgTa calcined product 100wt% of ₂ O _{9 2}
The powder is usually added in the range of 0.01 to 3% by weight, preferably 1.0% by weight or less. 1.0 wt
If the ratio is less than%, when a semiconductor element and an oscillator are combined, the influence on the oscillation frequency change caused by the temperature change is reversed between the semiconductor element and the BMT sintered body in a relatively wide temperature range, and they are offset. As a result, the stability of the oscillation frequency with respect to temperature tends to improve. Further, the addition amount of BaMgO ₂ is more preferably in the range of 0.3 wt% or less, and in this range, a very high Q value can be obtained. If it is less than 0.01 wt%, it tends to be difficult to obtain a sufficient addition effect, and if it exceeds 3 wt%, the Q value tends to be insufficient.

The BMT sintered body obtained by the method of the present invention has the following performance. Relative dielectric constant: around 24 ... 10 GHz Q value: 20000-35000 ... 10 GHz Resonance frequency temperature coefficient τ _f 4 ppm / ° C (3
0 ° C-80 ° C) Density: Approximately 99% ... 100% theoretical density of perfect sintered body
Finally, the third invention will be described. First, Ba as the main material
_A process for preparing a calcined product represented by ₃ ZnTa ₂ O ₉ will be described.

According to the stoichiometric ratio of BZT, the Ba component,
The starting material containing the Zn and Ta components is weighed. B
As the component a, for example, BaCO ₃ powder having good reactivity is suitable, but BaO powder may be used. As the Zn component, for example, ZnO powder is used. As the Ta component, for example, Ta ₂ O ₅ powder is used.

The above starting materials are thoroughly mixed with pure water at a weight ratio of 1.5 to 2 by a ball mill and then dried in air. After molding the mixed powder after drying using a mold, the obtained molded body is calcined in air at 800 to 900 ° C. for 3 to 10 hours (for example, firing at 850 ° C. for 5 hours is performed. ) Cool and then grind to a fine powder using a rotary ball mill. The powder of the calcined material of Ba ₃ ZnTa ₂ O ₉ usually has an average particle size of about 3 μm or less.

Now, Ba ₃ ZnTa ₂ O which is the main material is
The powder of ₉ calcined products will be completed. Next, a process of forming a powder of BaZnO ₂ which is an auxiliary material added to the main material will be described. According to the stoichiometric ratio of BaZnO _2, the Ba component and Z
The starting material containing the n components is weighed.

As the Ba component, for example, BaCO ₃ powder having good reactivity is suitable, but BaO powder may be used.
As the Zn component, for example, ZnO powder is used. The starting material for preparing BaZnO _{2 is} thoroughly mixed with pure water at a weight ratio of 2-3 times by a ball mill, and then dried in air. After molding the mixed powder after drying using a mold, the obtained molded body is fired in air at a temperature of about 900 to 1300 ° C. for about 18 to 30 hours and then cooled, and then pulverized by a vibration mill. And pulverize. The powder of BaZnO _{2 as} an auxiliary material usually has an average particle size of about 3 μm or less.

Now, Ba as a sub-material added to the main material is added.
A ZnO ₂ powder is completed. Next, steps for obtaining a sintered body using the ceramic powders of the main and auxiliary materials thus obtained will be described. The powder of the calcined material represented by Ba ₃ ZnTa ₂ O ₉ and the powder of BaZnO ₂ are thoroughly mixed with pure water in a weight ratio of about 1.5 using a ball mill, and then dried in air.

An appropriate amount of organic binder is added to the mixed powder after drying and the mixture is molded with a mold, and then the formed compact is subjected to main firing. Amount of organic binder added (solid content conversion)
Is about 0.01 to 0.06 wt% with respect to 100 wt% of the mixed powder, and examples of the binder include polyvinyl alcohol. In the main firing, it is usually 150
After heat treatment at 0 to 1550 ° C. for about 3 to 7 hours, the temperature is lowered to 1400 to 1450 ° C. and then 50 to 12 ° C.
A heat treatment for ordering Zn ions and Ta ions is performed for 0 hours.

Regarding the amount of BaZnO ₂ added, Ba ₃
BaZnO for ZnTa calcined product 100wt% of ₂ O _{9 2}
The powder is usually added in the range of 0.01 to 3% by weight, preferably 1.0% by weight or less. 1.0 wt
If the ratio is less than%, when a semiconductor element and an oscillator are combined, the influence on the oscillation frequency change caused by the temperature change is reversed between the semiconductor element and the BMT sintered body in a relatively wide temperature range, and they are offset. As a result, the stability of the oscillation frequency with respect to temperature tends to improve. Further, the addition amount of BaZnO ₂ is more preferably in the range of 0.3 wt% or less, and in this range, a very high Q value can be obtained. If it is less than 0.01 wt%, it tends to be difficult to obtain a sufficient addition effect, and if it exceeds 3 wt%, the Q value tends to be insufficient.

The BZT sintered body obtained by the method of the present invention has the following performance. Relative dielectric constant: around 28 ... at 10 GHz Q value: 10,000-13000 ... at 10 GHz Temperature coefficient of resonance frequency τ _f : around 3.5 ppm / ° C (30-80 ° C) Density: about 99% ..Theoretical density of perfect sintered body is 100%
To

[0035]

In the method for producing a sintered body for high frequency dielectrics according to the present invention, each of the sub-materials added to the calcined material represented by the composition formula of A ₃ BC ₂ O _{9 as} the main material is burned. Since the binding property is enhanced, a high-density sintered body can be reliably obtained. The powder of the calcined material, which is difficult to sinter as it is, can be easily made into a high-density sintered body. That is, each sub material plays a role of a sintering aid.

Of course, the sub-materials that have the effect of improving the sinterability are of course
Although it is a compound different from the calcined material that is the main material, it contains no elements other than the elements contained in the calcined material, so there are very few impurity elements, and there is virtually no adverse effect on other properties. With respect to the dielectric properties, the Q value, and the temperature coefficient of the resonance frequency, which are important performances of the sintered body, the excellent characteristics originally possessed by the sintered body are not significantly impaired.

In addition, the auxiliary material can be obtained in the same process by using the same starting material as the main material, and after adding the auxiliary material, it is necessary to use a special firing method which causes a cost increase in firing. However, the present invention is extremely easy to carry out, and an excellent high frequency dielectric can be obtained easily and at a low cost, since the same steps as the conventional ones are merely performed.

[0038]

Embodiments of the present invention will be described below. Needless to say, the present invention is not limited to the following embodiments. - Example of the first invention - - Example 1 was first prepared powder calcined product of Ba ₃ MgTa ₂ O ₉ as follows.

The starting materials BaCO ₃ powder, MgO powder and Ta ₂ O ₅ powder were weighed according to the stoichiometry of BMT. First, MgO powder and Ta ₂ O ₅ powder were thoroughly mixed in equimolar amounts with pure water at a weight ratio of 2 times and dried in air, and then this mixed powder was molded using a mold. .. Then, the obtained molded body is 120
After calcination in air at 0 ° C for 18 hours and then cooling,
It is crushed into fine powder using a vibration mill. Then again
Molding-calcination was performed twice more. The obtained MgT
The a ₂ O ₆ powder usually had an average particle size of 2 μm.

Then, MgTa ₂ O ₆ powder is mixed with BaCO ₃
The powder is thoroughly mixed with pure water in a weight ratio of 1: 3 with 1.5 times the weight ratio of pure water and then dried in air. After molding the mixed powder after drying using a mold, the obtained molded body is calcined in air at 1300 ° C. for 5 hours and then cooled, and then pulverized by using a rotary ball mill to form fine powder. , And then again, forming-calcining 2 more
The calcination process was performed three times for a total of three times. The powder of the finally obtained calcined product had an average particle size of 2 μm.

On the other hand, MgTa ₂ O ₆ powder was also prepared as follows. Starting material MgO powder and Ta ₂ O
_{5 The} powder was weighed according to the stoichiometric ratio of MgTa ₂ O ₆ ,
It was thoroughly mixed with pure water in a weight ratio of 2 using a resin ball mill, and then dried in air. After molding the mixed powder after drying using a mold, the molded body is baked in air at 1200 ° C. for 18 hours, cooled, and then pulverized by a vibration mill to obtain a powder of MgTa ₂ O _6. It was The average particle size of the obtained powder was about 2 μm.

Ba ₃ M which is the main material thus obtained
Powder of calcined product of gTa ₂ O ₉ and MgTa _{2 as an} auxiliary material
Powder O _6, MgTa to calcine 100 wt% ₂ O ₆
Was mixed with 0.3 wt% and was thoroughly mixed with 1.5 times by weight of pure water using a resin ball mill, followed by drying in air. 0.06 wt% of polyvinyl alcohol, which is an organic binder, is added to the mixed powder after drying and the mixture is molded with a mold, and then the molded body thus prepared is subjected to main firing. The dimensions of the molded body were 14 mm in diameter and 6 mm in height. In the main firing, heat treatment for ion ordering was performed at 1650 ° C. for 2 hours and then at 1400 ° C. for 80 hours to obtain a BMT sintered body.

[0043] - to calcined product 100 wt% of Example _{2- Ba 3 MgTa 2 O 9,} Mg
A BMT sintered body was obtained in the same manner as in Example 1 except that Ta ₂ O ₆ was added in an amount of 0.5 wt%. -Example 3- 100% by weight of Ba ₃ MgTa ₂ O ₉ calcined product
A BMT sintered body was obtained in the same manner as in Example 1 except that Ta ₂ O ₆ was added in a compounding amount of 0.8 wt%.

Example 4-Ba ₃ MgTa ₂ O ₉ calcination product 100 wt%, Mg
A BMT sintered body was obtained in the same manner as in Example 1 except that Ta ₂ O ₆ was added in an amount of 1.0 wt%. - except that no addition of powder of Comparative Example 1- MgTa ₂ O _6, the first embodiment
A BMT sintered body was obtained in the same manner as in.

-Example of the Second Invention- Example 5-The powder of the calcined material of Ba ₃ MgTa ₂ O ₉ which is the main material is
The one obtained in Example 1 was used. On the other hand, BaMgO ₂ powder was prepared as follows.

BaCO ₃ powder and MgO powder as starting materials were weighed in accordance with the stoichiometric ratio of BaMgO ₂ , thoroughly mixed with pure water having a weight ratio of 2 by a ball mill made of resin, and then dried in air. .. After molding the mixed powder after drying using a mold, the molded body was dried in air at 950 ° C for 2 minutes.
BaMgO ₂ powder was obtained by firing for 0 hours, cooling, and then pulverizing with a vibration mill. The average particle size of the obtained powder was about 2 μm.

Then, Ba ₃ MgTa ₂ O as the main material is used.
The powder of ₉ calcination products and the powder of BaMgO ₂ which is an auxiliary material are added to 0.3 wt% of BaMgO ₂ to 100 wt% of the calcination products.
Was mixed with 1.5 parts by weight of pure water in a resin ball mill, and then dried in air.
After adding 0.06 wt% of polyvinyl alcohol, which is an organic binder, to the mixed powder after drying and molding with a mold,
The formed body is fired. The dimensions of the molded body were 14 mm in diameter and 6 mm in height. In the main firing, 1650
A heat treatment for ion ordering was performed at 5 ° C. for 5 hours and then at 1400 ° C. for 80 hours to obtain a BMT sintered body.

Example 6 Ba ₃ MgTa ₂ O ₉ 100 wt% calcination product, Ba
A BMT sintered body was obtained in the same manner as in Example 5 except that MgO ₂ was added in an amount of 0.5 wt%. - to calcined product 100 wt% of Example _{7- Ba 3 MgTa 2 O 9,} Ba
A BMT sintered body was obtained in the same manner as in Example 5 except that MgO ₂ was added in an amount of 0.8 wt%.

[0049] - to calcined product 100 wt% of Example _{8- Ba 3 MgTa 2 O 9,} Ba
A BMT sintered body was obtained in the same manner as in Example 5 except that MgO ₂ was added in an amount of 1.0 wt%. - except that no addition of powder of Comparative Example 2- BaMgO ₂ got BMT sintered body in the same manner as in Example 5.

-Example of _Third Invention- Example 9-First, a powder of a calcined material of Ba ₃ ZnTa ₂ O ₉ was prepared as follows. Starting material BaCO ₃ powder, Z
nO powder and Ta ₂ O ₅ powder were weighed according to the stoichiometric ratio of BZT, and the weight ratio was 1.
It was thoroughly mixed with 5 times pure water and then dried in air. After molding the mixed powder after drying using a mold, the molded body is calcined in air at 850 ° C. for 5 hours and then cooled.
Then, the powder was pulverized by a rotary ball mill to obtain a powder of a calcined product represented by Ba ₃ ZnTa ₂ O ₉ . The average particle size of the obtained powder was about 2 μm.

On the other hand, BaZnO ₂ powder was prepared as follows. Starting materials BaCO ₃ powder and ZnO
The powder was weighed according to the stoichiometric ratio of BaZnO ₂ , thoroughly mixed with 1.5 times by weight pure water in a resin ball mill and then dried in air. The mixed powder after drying was molded using a mold, the molded body was baked in air at 950 ° C. for 20 hours, cooled, and then pulverized with a vibration mill to obtain a BaZnO ₂ powder. The average particle size of the obtained powder was about 2 μm.

Ba ₃ Z, which is the main material thus obtained,
Powder of calcined nTa ₂ O ₉ and BaZnO as an auxiliary material
Drying in air is mixed thoroughly with ₂ powder, the calcined product 100 wt% resin ball mill along with 1.5 times of pure water in a weight ratio by blending BaZnO ₂ at 0.3 wt% relative did. 0.06 wt% of polyvinyl alcohol, which is an organic binder, is added to the mixed powder after drying and the mixture is molded with a mold, and then the molded body thus prepared is subjected to main firing. The dimensions of the molded body were 14 mm in diameter and 6 mm in height. In the main firing, a heat treatment for ion ordering was performed at 1550 ° C. for 5 hours and then at 1400 ° C. for 80 hours to obtain a BZT sintered body.

Example 10 Ba ₃ ZnTa ₂ O ₉ calcination product 100 wt%, Ba
Example except that ZnO ₂ was added in an amount of 0.5 wt%
A BZT sintered body was obtained in the same manner as in 13. - to calcined product 100 wt% of Example _{11- Ba 3 ZnTa 2 O 9,} Ba
Example except that ZnO ₂ was added in an amount of 0.8 wt%
A BZT sintered body was obtained in the same manner as in 13.

[0054] - to calcined product 100 wt% of Example _{12- Ba 3 ZnTa 2 O 9,} Ba
Example except that ZnO ₂ was added in an amount of 1.0 wt%
A BZT sintered body was obtained in the same manner as in 13. - except that no addition of powder of Comparative Example 3- BaZnO ₂ got BZT sintered body in the same manner as in Example 13.

The relative permittivity, Q value, temperature coefficient of resonance frequency and density were measured for each of the sintered bodies of Examples and Comparative Examples. The measurement results are shown in Tables 1 to 3 below. The Q value was measured according to the cylinder resonance method. The measurement frequency is 7 GHz and Q × f = Q at 10 GHz using the constant relationship
The value was calculated. A resonator having a diameter of 12 and a height of 5 mm was obtained from each sintered body and then polished to form a resonator.
Pure copper plates (diameter 44 mm) are used for the metal plates that sandwich the resonator under test.
, And the effective conductivity σe was 80% of the DC conductivity σo of copper (σe = 0.8 × σo). The analyzer used for the measurement is (Hewlett Packard 8720A).

In the case of the cylindrical resonance method, a TE mode dielectric resonator is designed and created based on the dielectric constant of a high frequency dielectric, and the created resonator is sandwiched between copper plates having a diameter of about 4 times the diameter of the network analyzer. To measure the resonance frequency of the resonator and the full width at half maximum of resonance. The Q value directly calculated from the measured value of the network analyzer at this time includes the loss due to the copper plate. The loss due to the surface resistance of the copper plate is included as an error component.

In order to calculate the Q value of only the high frequency dielectric itself, it is necessary to remove the error due to the loss in the copper plate. However, if the frequency is as high as 10 GHz, the high-frequency current flows only on the surface of the copper plate, so even if the direct current conductivity σo of copper is applied as it is to calculate the loss in the copper plate, it will not be a correct value, and the microwave region It is necessary to obtain the effective conductivity σe at and apply this. TE ₀₁₁ mode resonator and TE made from the same sintered body have the same effective conductivity.
_The surface resistance is obtained based on the difference between the resonance frequency in the _13- mode resonator and the Q value directly obtained by the network analyzer, and the ratio of effective conductivity σe / copper DC conductivity σo is calculated from this result. In this case, this ratio is 0.8
That is why. From the obtained results, Q due to the surface resistance of the copper plate
A value is obtained, and a correction operation is performed by subtracting the obtained Q value from the obtained Q value due to the surface resistance of the copper plate to finally obtain the Q value of each sintered body.

Regarding the temperature coefficient of the resonance frequency, a dielectric resonator of TE mode is designed and produced, and the shift amount of the resonance frequency is measured by changing the temperature in the range of 30 to 50 ° C. or 30 to 80 ° C. It is obtained by dividing the shift amount by the temperature change amount.

[0059]

[Table 1]

[0060]

[Table 2]

[0061]

[Table 3]

As shown in Tables 1 to 3, according to the present invention, even if the calcined product is not sintered as in Comparative Examples 1 to 3, the relative dielectric constant can be obtained only by adding the above-mentioned sub materials. Rate, Q value,
It is well understood that it becomes easy to obtain a sintered body for a high frequency dielectric, which has a sufficient temperature coefficient and density of the resonance frequency. In addition, for further comparison, except that the powder of BaMgO ₂ was not added and the compact was inserted into an electric furnace heated to 1650 ° C. and the temperature was rapidly raised during the main firing, the results were the same as in Example 1. Similarly, a BMT sintered body was obtained.
In this case, the relative dielectric constant was 24.5, the Q value was 26000, and the density was 97%. However, the table on which the compact was placed was broken and could not be reused. Comparing this data with the data of Example 1, it will be understood that in the case of the present invention, the one having good performance can be obtained at a low cost without the need for the rapid temperature rise which causes the cost increase during the firing. ..

[0063]

In the method for producing a sintered body for high frequency dielectrics according to the first to third aspects of the present invention, since each auxiliary material added to the calcined material as the main material enhances the sinterability, high density sintering is achieved. Not only can the body be easily obtained, but each sub-material that has the effect of improving the sinterability has an extremely thin impurity character that causes a decrease in the Q value. It has excellent characteristics originally, and each auxiliary material can be obtained in the same process using the same starting material as the main material, and after the addition of the auxiliary material, a special cost that causes an increase in cost during firing. Since it is not necessary to use a firing method and only the same steps as in the past are performed, an excellent sintered body for a high frequency dielectric can be easily obtained at low cost.

If the addition amount of each sub-material is 0.01 to 3 wt% with respect to 100 wt% of the calcined product, the effect of adding the sub-materials will surely occur in an appropriate state.

Claims (6)

[Claims] 1. Ba₃MgTa₂O₉Temporary represented
Manufacture of BMT sintered body for firing and sintering the fired product
In the manufacturing method, MgTa is added to the calcined product.₂O ₆Added
Of the BMT sintered body characterized by being fired by
Production method. _2. The additive amount of MgTa ₂ O ₆ is Ba ₃ MgT.
0.0 per 100 wt% of the calcined product represented by a ₂ O ₉
The method for producing a BMT sintered body according to claim 1, which is 1 to 3 wt%. 3. A method for producing a BMT sintered body, which comprises firing a calcined material represented by Ba ₃ MgTa ₂ O ₉ to sinter it, wherein BaMgO ₂ is added to the calcined material and fired. A method for manufacturing a BMT sintered body, comprising: 4. The added amount of BaMgO ₂ is Ba ₃ MgTa.
0.01 for 100 wt% of calcined product expressed by ₂ O ₉
The method for producing a BMT sintered body according to claim 3, wherein the content is 3 wt%. 5. A method for producing a BZT sintered body, which comprises firing a calcined material represented by Ba ₃ ZnTa ₂ O ₉ to sinter it, wherein BaZnO ₂ is added to the calcined material and fired. A method of manufacturing a BZT sintered body, comprising: 6. The additive amount of BaZnO ₂ is Ba ₃ ZnTa.
0.01 for 100 wt% of calcined product expressed by ₂ O ₉
The method for producing a BZT sintered body according to claim 5, wherein the content is ˜3 wt%.