JPH05279111A - Porcelain composition of dielectric material and its production - Google Patents

Abstract

PURPOSE:To improve no-load Q value by calcining a raw material composition so as to leave BaCO3 during calcination and producing a porcelain composition of dielectric material comprising an oxide of complex perovskite type structure of the formula. CONSTITUTION:Raw material powder such as BaCO3, ZnO, NiO, CoO, Nb2O5, Ta2O5, etc., are weighed so as to give a given molar ratio and blended in a wet state to give a raw material composition. Then the raw material is dried, calcined at 800-950 deg.C so as to leave a Ba component, ground in a wet state and granulated. The granules are press molded and the molded article is burnt in the atmosphere at about 1,400 deg.C for a given time to give a porcelain composition of dielectric material comprising an oxide of complex perovskite type structure of the formula (0<x<1, 0<y<1, 0<z<1, 0<w<1; x+y+z=1), having high no-load Q value.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a dielectric ceramic composition particularly preferably used for high frequencies and a method for producing the same.

[0002]

BACKGROUND ART In recent years, dielectric ceramics have been widely used in dielectric resonators, dielectric substrates for MICs (high frequency integrated circuits), etc. in high frequency regions such as microwaves and millimeter waves. By the way, in this type of dielectric ceramic, a) the relative permittivity (εr) is large, b) the unloaded Q is large,
c) It is required that the temperature coefficient (τf) of the resonance frequency is small. Therefore, as a porcelain composition that satisfies all these conditions, it has been conventionally indicated by A (B _1/3 B ′ _2/3 ) O ₃ . Oxides having a complex perovskite structure are widely studied.

For example, in Japanese Unexamined Patent Publication (Kokai) No. 62-87453, a Ba (Zr, Zn, Ni, Ta, Nb) O-based composition has no load Q = 13000 to 17700, ε.
r = 29.5 to 32.0, τf = −2 to +8 ppm / ° C.
In Japanese Patent Application Laid-Open No. 2-95453, in the Ba (Zn, Mg, Ni, Ta, Nb) O-based composition, no load Q = 9500 to 23000, εr.
= 25.4 to 34.1, τf = -7.0 to +9.9 pp
The characteristics of m / ° C are realized, and it is shown as a porcelain material having a high unloaded Q and excellent temperature characteristics.

Further, in order to further improve the no-load Q value of such a porcelain material, JP-A-62-25200
No. 8 discloses that Ba (Co, Zn, Nb) O-based composition is annealed in a nitrogen atmosphere with respect to the sintered body.
In Japanese Patent No. 64559, Ba (Mg, Zn, N
b, Ta) O-based composition, a two-step calcination operation is adopted. First, the B-site raw material is calcinated at 1250-1400 ° C., then mixed with the A-site raw material, and again 1100-1.
Techniques such as calcination at 200 ° C have been proposed.

However, regarding the porcelain composition, in the above-mentioned Japanese Patent Laid-Open No. 62-87453, high unloaded Q
In order to obtain the above, there is a problem that it is necessary to adopt a fairly high firing temperature of 1550 ° C., and a large Ta /
Since the Nb ratio (molar ratio) is adopted, T
The amount of a used inevitably increased, which was disadvantageous in terms of cost. Further, in the porcelain composition disclosed in JP-A-2-95453, high temperature firing at 1450 to 1650 ° C. is required, and in this respect, there is a problem in terms of cost.

On the other hand, regarding the manufacturing process, in order to realize a higher no-load Q, the above-mentioned JP-A-62-252 is used.
In many cases, complicated processes such as those disclosed in Japanese Patent Laid-Open No. 008 and Japanese Patent Laid-Open No. 1-264559 are required, which has a problem in productivity.

[0007]

The present invention has been made in view of such circumstances, and its object is to provide a dielectric material having a sufficiently large unloaded Q value and excellent temperature characteristics. It is to provide a porcelain composition, and to provide a method capable of economically producing such a dielectric porcelain composition without using a complicated process.

[0008]

In order to solve the problem, the present invention provides the following general formula: Ba [(Co _x Ni _y Zn _z ) _1/3 (Nb _w Ta _1-w ) _2/3 ] O ₃ ( However, a dielectric material comprising an oxide having a complex perovskite structure represented by 0 <x <1,0 <y <1,0 <z <1,0 <w <1, x + y + z = 1) The gist is a porcelain composition.

The present invention also provides the following general formula: Ba [(Co _x Ni _y Zn _z ) _1/3 (Nb _w Ta _1-w ) _2/3 ] O ₃ (where 0 <x <1, 0 <y <1,0 <z <1,0 <w <1, x + y + z = 1) When manufacturing a dielectric ceramic composition composed of an oxide having a complex perovskite structure, such a dielectric ceramic composition Calcination of the raw material composition for giving a barium carbonate, which is contained in the raw material composition and serves as the Ba component in the above general formula, remains in the calcinated material. The manufacturing method of the composition is also the gist thereof.

[0010]

SPECIFIC STRUCTURE As described above, the dielectric ceramic composition according to the present invention comprises BaO, CoO, NiO, ZnO, Nb.
Ba [(Co, Ni, Zn) _1/3 (Nb, T) having a complex perovskite structure composed of ₂ O ₅ and Ta ₂ O _5.
a) _2/3 ] O ₃ as a main component, which is in the form of a solid solution of each of the above component oxides, among which Co, Ni, Zn (x, y, z) The ratio of can be any value within the range of 0 to 1 mol (excluding 0 mol and 1 mol) at a ratio (x + y + z = 1) where the total amount thereof is 1 mol. It is a thing. In addition, preferably, 0.1 ≦ x ≦ 0.8, 0 <y
Within the range of ≦ 0.7, 0.2 ≦ z ≦ 0.8, x,
It is desirable that the values of y and z be determined, whereby a high no-load Q value and good temperature characteristics can be advantageously imparted.

Further, in such a porcelain composition, Nb
Even in the proportions of (w) and Ta (1-w), any proportion may be used within the range of 0 to 1 mole (excluding 0 mole and 1 mole) in such a proportion that the total amount thereof is 1 mole. However, it is preferable that w be 0.4 or more, and more preferably 0.6 or more, from the viewpoint of suppressing the cost increase.

The porcelain composition is characterized in that it can be sufficiently densified in the atmosphere at a firing temperature of about 1400 ° C., and thus a dielectric porcelain having excellent characteristics can be obtained. There is.

By the way, the general formula of the present invention as described above: Ba [(Co _x Ni _y Zn _z ) _1/3 (Nb _w Ta
_1-w ) _2/3 ] O ₃ represented by the complex perovskite type oxide is known to be Ba, Co, Ni, Z.
The oxides of n, Nb, and Ta, or the compounds that give the oxides are used as raw materials, and these components are solid-solved to form an oxide having a complex perovskite structure. In the production of a dielectric porcelain composition made of a material, a conventionally known method is appropriately adopted. For example, according to a powder molding method, a calcined powder obtained by calcining a mixture of the above raw material components. If necessary, an organic binder is added to the mixture, the mixture is granulated, pressure-molded into a predetermined shape, and then fired to obtain the intended dielectric ceramic.

According to the present invention, in the production of such a dielectric ceramic composition, calcination of the raw material composition which gives such a dielectric ceramic composition is advantageously performed in the raw material composition. The contained barium carbonate, which is the Ba component in the general formula, is contained in the calcined product. In other words, the calcination of this raw material composition is
Barium carbonate as a raw material used for compounding in the product after calcination does not contribute to the production of the target composite perovskite, and is performed under such a condition that it remains unreacted, Specifically, it is carried out by adopting a calcination temperature of up to 950 ° C. and holding it at such a temperature for 1 minute or more, preferably for 1 to 7 hours, whereby the dielectric ceramic is unloaded. The Q characteristic will be further improved. The too low calcination temperature is
It is generally desirable to set the calcination temperature to more than 800 ° C., because it is difficult to carry out substantial calcination and it becomes difficult to effectively densify the raw material composition.

[0015]

EXAMPLES Some examples of the present invention will be shown below to clarify the present invention in more detail. However, the present invention is not limited by the description of such examples. Needless to say, it is not something to receive. In addition to the following embodiments, the present invention is not limited to the above specific description, and various changes and modifications are made based on the knowledge of those skilled in the art without departing from the spirit of the present invention. It is to be understood that improvements, etc. can be added.

Example 1 First, commercially available barium carbonate, zinc oxide, nickel oxide,
Powders of cobalt oxide, niobium pentoxide, and tantalum pentoxide were prepared, and the composition of the final product dielectric porcelain was as shown in Table 1 below.
After weighing each of them so as to have the composition as shown in Fig. 1, those raw material components were put into a polyethylene pot together with zirconia cobblestone and pure water and subjected to a wet mixing operation for 16 hours to obtain 11 kinds of raw materials. A composition was obtained. Then, after drying each raw material composition, calcination is performed in an alumina crucible at 1100 ° C. for 4 hours, and the calcinated product is wet with zirconia boulders and pure water in a polyethylene pot for 16 hours. Granulation was performed by crushing and further passing through a 40-mesh sieve.

Next, each of the granulated powders was pressed with a press molding machine at a surface pressure of 1 ton / cm ² and a diameter of:
It was formed into a disk shape having a thickness of 12 mm and a thickness of about 6 mm, and the obtained molded product was further baked in the air at a temperature of 1400 ° C. for 10 hours.

The relative permittivity (εr), no-load Q value, and temperature coefficient (τf) of the resonance frequency of each of the disc-shaped fired bodies thus obtained were measured, and the results are shown in Table 1 below. Indicated. The values of relative permittivity (εr) and unloaded Q are
Each of them was measured by a known parallel conductor plate type dielectric resonator method, and the Q value thereof was converted into a value of 3 GHz in Table 1. Further, the temperature coefficient (τf) of the resonance frequency is −
Calculated from the temperature change of the resonance frequency in the temperature range of 25 to + 75 ° C., the temperature characteristics are shown in Table 1.

[0019]

[Table 1]

As is clear from the results shown in Table 1, Ba, Co, N in a predetermined ratio (0 <x, y, z, w <1)
In the case of containing i, Zn, Nb, and Ta (Sample No.
2 to 10), a dielectric porcelain having an excellent relative permittivity and an unloaded Q and an excellent temperature characteristic (τf) can be obtained. 1 or No. Like 11, Co and Ta
When there is no (x = 0, w = 1), the value of the no-load Q is low.

Example 2 As in Example 1, commercially available powders of barium carbonate, zinc oxide, nickel oxide, cobalt oxide, niobium pentoxide and tantalum pentoxide were prepared, and the composition of the final product dielectric porcelain was prepared. Are weighed so as to have the composition shown in Table 2 below, and then the raw material components thereof are put into a polyethylene pot together with zirconia boulders and pure water, and 1
A wet mixing operation was performed for 6 hours to obtain 7 types of raw material compositions. Then, after drying each raw material composition, in the alumina crucible, the calcination temperature shown in Table 2 below was adopted and calcination was carried out for 4 hours, and the calcination product was further placed in a polyethylene pot. , Zirconia cobblestone, and pure water were wet-milled for 16 hours, and further passed through a 40-mesh sieve for granulation.

Next, each of the granulated powders was pressed with a press molding machine at a surface pressure of 1 ton / cm ² and a diameter of:
It was formed into a disk shape having a thickness of 12 mm and a thickness of about 6 mm, and the obtained molded product was further baked in the air at a temperature of 1400 ° C. for 10 hours.

With respect to various disc-shaped fired bodies thus obtained, the relative permittivity (εr), no-load Q value, and temperature coefficient (τf) of resonance frequency were measured in the same manner as in Example 1, The results are also shown in Table 2 below. In addition, the sample No. The X-ray diffraction chart of the 840 ° C. calcined product obtained in No. 12 is shown in FIG. 1, and its partially enlarged view is shown in FIG. 2.

[0024]

[Table 2]

As is clear from the results shown in Table 2, 1
Sample No. adopting a calcination temperature of 100 ° C. Sample N with a calcination temperature of 950 ° C or lower for the unloaded Q values of 3 and 9
o. In the case of 12 to 18, the larger no-load Q
It was recognized that it had a value.

[0026]

As is apparent from the above description, according to the present invention, a predetermined Ba [(Co, Ni, Zn) _1/3 (N
b, Ta) _2/3 ] O ₃ based composite perovskite type oxide is used, and a dielectric material having a sufficiently high unloaded Q value at a firing temperature of about 1400 ° C. and excellent temperature characteristics. It is now possible to manufacture porcelain, and by adopting a calcination temperature of 950 ° C or lower, it is possible to manufacture a dielectric porcelain with an improved unloaded Q value without using a complicated process. It was decided to get it.

[Brief description of drawings]

FIG. 1 shows a sample No. 1 in Example 2. 12 is a view showing an X-ray diffraction chart of a calcined product at 840 ° C. obtained as No. 12;

FIG. 2 is a partially enlarged view of the X-ray diffraction chart shown in FIG.

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[Procedure amendment]

[Submission date] April 7, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

Example 1 First, commercially available barium carbonate, zinc oxide, nickel oxide,
Powders of cobalt oxide, niobium pentoxide, and tantalum pentoxide were prepared, and the composition of the final product dielectric porcelain was as shown in Table 1 below.
Each of the 14 raw materials was weighed and put into a polyethylene pot together with zirconia cobblestone and pure water, and the mixture was wet-mixed for 16 hours. A composition was obtained. Then, after drying each raw material composition, calcination is performed in an alumina crucible at 1100 ° C. for 4 hours, and the calcinated product is wet with zirconia boulders and pure water in a polyethylene pot for 16 hours. Granulation was performed by crushing and further passing through a 40-mesh sieve.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0019

[Correction method] Change

[Correction content]

[0019]

[Table 1]

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction content]

As is clear from the results shown in Table 1, Ba, Co, N in a predetermined ratio (0 <x, y, z, w <1)
In the case of containing i, Zn, Nb, and Ta (Sample No.
2 to 13 ), a dielectric ceramic having an excellent relative permittivity and an unloaded Q and an excellent temperature characteristic (τf) can be obtained. 1 or No. As shown in 14 , Co and Ta
When there is no (x = 0, w = 1), the value of the no-load Q is low.

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0023

[Correction method] Change

[Correction content]

With respect to various disc-shaped fired bodies thus obtained, the relative permittivity (εr), no-load Q value, and temperature coefficient (τf) of resonance frequency were measured in the same manner as in Example 1, The results are also shown in Table 2 below. In addition, the sample No. The X-ray diffraction chart of the 840 ° C. calcined product obtained in No. 15 is shown in FIG. 1, and its partially enlarged view is shown in FIG. 2.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0024

[Correction method] Change

[Correction content]

[0024]

[Table 2]

[Procedure Amendment 6]

[Document name to be amended] Statement

[Name of item to be corrected] 0025

[Correction method] Change

[Correction content]

As is clear from the results shown in Table 2, 1
Sample No. adopting a calcination temperature of 100 ° C. Sample N whose calcination temperature is 950 ° C. or lower for the unloaded Q values of 3 and 11
o. In the case of 15 to 21 , the larger unloaded Q
It was recognized that it had a value.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 shows a sample No. 1 in Example 2. 15 is a diagram showing an X-ray diffraction chart of a calcined product at 840 ° C. obtained as 15. FIG.

FIG. 2 is a partially enlarged view of the X-ray diffraction chart shown in FIG.

Claims (2)

[Claims] 1. A general formula: Ba [(Co _x Ni _y Zn _z ) _1/3 (Nb _w Ta _1-w ) _2/3 ] O ₃ (where 0 <x <1, 0 <y <1, 0 <z <1,0 <w <1, x + y + z = 1) A dielectric ceramic composition characterized by comprising an oxide having a complex perovskite structure. 2. A general formula: Ba [(Co _x Ni _y Zn _z ) _1/3 (Nb _w Ta _1-w ) _2/3 ] O ₃ (where 0 <x <1, 0 <y <1, 0 <z <1,0 <w <1, x + y + z = 1) When producing a dielectric ceramic composition composed of an oxide having a complex perovskite structure represented by the following formula, a raw material composition which gives such a dielectric ceramic composition A method for producing a dielectric ceramic composition, wherein calcination is performed such that barium carbonate, which is a Ba component in the above general formula, contained in the raw material composition remains in the calcination product.