JP3067814B2 - Dielectric porcelain composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a dielectric porcelain composition, and more particularly to a dielectric porcelain composition exhibiting a high Q value and a relative dielectric constant and exhibiting a temperature coefficient in a practical range. The present invention relates to a dielectric porcelain composition easily manufactured by sintering. INDUSTRIAL APPLICABILITY The present invention is used for a dielectric resonator, a microwave integrated circuit board, impedance matching of various microwave circuits, and the like in a micro frequency range.

[0002]

2. Description of the Related Art Since dielectric loss tends to increase as the operating frequency becomes higher, a dielectric ceramic composition having a large Q value in a micro frequency range is desired. As a conventional porcelain material, ZrO ₂
—SnO ₂ —TiO ₂ based porcelain composition, BaO—TiO ₂
There are known a porcelain composition and a porcelain composition in which a part thereof is replaced with another element (Japanese Patent Publication No. 1-38077).

[0003]

However, in the conventional porcelain composition, the Q value or the relative dielectric constant is small, the desired temperature coefficient cannot be obtained, or the sinterability in the production is poor. There is a problem. Further, a new dielectric ceramic composition having a different composition is desired, and more preferably, it is excellent in its sinterability and can be easily produced. The present invention has been made in view of the above viewpoints, and has a dielectric ceramic composition having a high Q value and a relative dielectric constant and exhibiting a temperature coefficient in a practical range. It is an object to provide a body porcelain composition.

[0004]

Means for Solving the Problems The present inventors have proposed Ba-Zn.
As a result of various studies on a -Ta-Ti-O-based dielectric porcelain composition that satisfies all of the following performances, the present invention has been completed. Q value: 5000 or more (in the case of 4.5 GHz) relative dielectric constant epsilon _r; 30 or more the temperature coefficient _{τ f; -20~ + 20 ppm /} ℃ sinterable; good. That is, the dielectric porcelain composition of the present invention is composed of barium oxide, zinc tantalate and titanium oxide.
When represented by aO.xZnTa ₂ O ₆ .yTiO ₂ ,
x and y are respectively 0.1 <x <0.8, 3.5 <y <
A composition in the range of 4.5 as a main component and W as a subcomponent
O ₃ alone or select both MnO ₂ and WO ₃
With respect to the main component as 100 parts by weight, WO ₃ is allowed to contain additives in the range of 0.1 to 1 part by weight, MnO ₂ is characterized by comprising by addition contains at least 0.5 parts by weight or less. The present porcelain composition is manufactured by mixing a predetermined amount of a predetermined raw material and sintering. For example, a raw material powder that becomes BaO after sintering, a ZnTa ₂ O ₆ powder, and a TiO ₂ powder are mixed in an amount corresponding to the above composition formula and calcined to obtain BaO.xZnTa ₂ O.
_6. yTiO ₂ calcined powder is produced, and a predetermined amount of Mn
It can be manufactured by sintering O ₂ powder and WO ₃ powder.

[0005]

The present invention will be described in detail with reference to the following examples. (1) Preparation of each sample ZnO and Ta ₂ O ₅ having a purity of 99.9% were weighed and mixed so as to have a molar ratio of 1: 1 as starting materials, and these were subjected to dry pulverization and mixing by a mixer. After that, a heat treatment is performed for 6 hours at a temperature of
a ₂ O ₆ was synthesized. The thus obtained ZnTa ₂ O ₆
A predetermined amount of BaCO ₃ and TiO ₂ having a purity of 99.9% is weighed and mixed in accordance with each composition, and then subjected to dry primary pulverization and mixing again with a mixer, and then calcined at a temperature of 1000 ° C. for 6 hours in an oxygen atmosphere. did. Furthermore, after adding the MnO ₂ powder and WO ₃ powder to the calcined product, and again subjecting the mixture to dry secondary grinding and mixing with a mixer, an appropriate amount of an organic binder and water were added, followed by grinding with a 30 mmφ alumina ball. Granulated by spray drying, and the granulated raw material is 1500 k
It was formed into a disk shape of 18 mmφ × 15 mmt (thickness) under a press pressure of g / cm ² . Next, the molded body is placed in the atmosphere,
Firing at a temperature of 1250 ° C. to 1350 ° C. for 10 hours,
Finally, it was polished into a disk shape of 12 mmφ × 10 mmt (thickness) to obtain a dielectric sample. Then, the Q value (1 / tan
δ), the relative permittivity ε _r , and the temperature coefficient τ _f of the resonance frequency were measured using a sample having a sintering temperature at which the relative permittivity ε _r became the highest. The ε _r and Qu values were measured by the dielectric resonator method. τ _f is in the range of −30 to 80 ° C., and τ _f = −1 / 2τ
It was determined from the ε-α equation. The resonance frequency is approximately 4.5 GHz. The linear expansion coefficient α is 9.5 to 11 ppm / ° C.
τε is the temperature coefficient of the dielectric constant epsilon _r. The determination of the sinterability is performed by determining whether micro and macro cracks are present or whether the sintered body is sufficiently contracted by sintering in the entire sintering temperature range. Indicates that cracks were present, and the others were marked with ○.

(2) Performance evaluation The characteristics of each of the above dielectric samples were examined and are shown in Tables 1, 2 and 3. In addition, in the core table, the part indicated by * indicates a number not included in the present invention. In addition, in the "Comprehensive evaluation" column,
The Q value, the relative permittivity ε _r and the temperature coefficient τ _f are included in the above practical range, but show a case where the sinterability is not sufficient.

[Table 1]

[Table 2]

[Table 3] According to these results, the amount of ZnTa ₂ O ₆ added was x
In the case where it is as small as 0.1 (No. 1), the τ _f is too large as 25, and in the case where it is as large as 0.8 (Nos. 6 and 20), the Q values are as small as 2500 and 4000 respectively. The amount of TiO ₂ added is y
= 3.3, 3.4, 3.5 (No. 7 to
9) has an ε _r of 28.3 to 29.6 and less than 30,
When the number is as large as 4.5 (No. 14), τ _f is too small as −21. When no WO ₃ component is contained (No. 3)
3, 35) have small Q values of 3800 and 4100, respectively.
When the content is as high as 1.1 parts by weight (Nos. 26 and 28),
The values are as small as 4600 and 3800 respectively. Further, MnO ₂
When the components are contained as much as 0.6 parts by weight (No. 22, 2
In 4), the Q value is as small as 4800 and 4000 respectively. From the above, the composition formula of the calcined powder: BaO.xZnTa ₂ O ₆ .y
In TiO ₂ , 0.1 <x <0.8, 3.5 <y <
4.5 and the amount of WO ₃ component is 0.1 to 1 part by weight (No. 2 to 5, 10 to 13, 16 to 19, 21, 2
3, 25, 27, 29 to 32, 34, and 36) have a Q value of 5,000 or more, a relative dielectric constant of 30 or more, and a temperature coefficient of -20 to +20, and have all practical performances. Will be satisfied. Furthermore, both the case where the MnO ₂ component was not contained (Nos. 29 and 31) and the case where the MnO ₂ component was contained as much as 0.6 parts by weight (Nos. 22 and 24) were poor in sinterability. On the other hand, when it contained 0.1 to 0.5 parts by weight, the sinterability was also good. Therefore, when the MnO ₂ content is 0.1 to 0.5 parts by weight, the Q value, the relative dielectric constant and the temperature coefficient are included in the practical range, and the MnO ₂ content when producing a sintered body is further reduced. It is excellent in sinterability and shows even more practicality with excellent balance. It should be noted that the present invention is not limited to the specific embodiments described above, but may be variously modified within the scope of the present invention according to the purpose and application. That is, various calcination conditions such as the calcination temperature and calcination conditions such as the calcination temperature can be selected. In addition, as a raw material to be BaO, a peroxide, a hydroxide, a nitrate, or the like can be used in addition to BaCO ₃ .

[0007]

As described above, the dielectric ceramic composition of the present invention has a Q value of 5,000 or more (at 4.5 GHz), a relative dielectric constant ε _{r of} 30 or more, and a temperature coefficient τ _{f of} -20. ~ +
It is very practically excellent and satisfies all the performances of 20 ppm / ° C. In addition, 0.5 parts by weight or less of MnO
_The dielectric porcelain composition containing ₂ satisfies all of the above-mentioned performances, has excellent sinterability in the production thereof, and exhibits even more balanced practicality.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C04B 35/42-35/49 CA (STN) REGISTRY (STN)

Claims (1)

(57) [Claims] 1. A composition comprising barium oxide, zinc tantalate and titanium oxide, the composition formula of which is BaO.xZnTa ₂ O.
When represented by ₆ · yTiO ₂ , x and y are each 0.
1 <x <0.8,3.5 <a main component composition in the range of y <4.5, WO ₃ plain as an auxiliary component, or Mn
Both O ₂ and WO ₃ are selected, and WO ₃ is added and contained within a range of 0.1 to 1 part by weight, and MnO ₂ is added and contained at least 0.5 part by weight or less based on 100 parts by weight of the main component. A dielectric porcelain composition, characterized in that it is formed by: