JP2684248B2 - Dielectric porcelain composition for electronic devices - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric ceramic composition for electronic devices, and more particularly to an improvement in a dielectric ceramic composition comprising a complex perovskite type compound used in the SHF band. by containing, it was hardly sintered material Ba (1 / 3Mg · 2 / 3Ta) electronic devices dielectric ceramic composition improves the sinterability was no sintering of excellent porcelain O ₃ Regarding

[0002]

2. Description of the Related Art Dielectric ceramic compositions for various electronic devices that make use of the fact that the properties of ceramic compositions are low loss and have good temperature characteristics are low loss in the SHF band, including capacitors for temperature compensation. There are various dielectric porcelain compositions used for dielectric resonators for direct reception of satellite broadcasts, down converters, etc., microwave strip line substrates and the like.

In general, the dielectric ceramic composition used for the SHF band, conventional, even in perovskite preparative compounds, in particular, are widely used composite perovskite compound having the following composition. Ba (1 / 3B · 2 / 3A) O ₃ where A; Ta, B; divalent metal ion (Mg or one or more of Zn, Ni, Co, Mn, etc.).

For example, Ba (1 / 3Mg · 2 / 3Ta)
There is an O ₃ type material (hereinafter referred to as BMT type material).
High ε required for dielectric ceramic composition used in HF band
The characteristics such as r, high Q, and τ f = 0 are severe, and in order to meet such characteristics, BMT materials are difficult to sinter, and rapid temperature rising sintering and sintering in oxygen are required for a long time. Sintering, for example, a temperature rising rate of 500 to 1000 ° C./min, 1500 to
Sintering at 1600 ° C. for about 100 hours was required.

[0005]

However, due to such sintering conditions, it was difficult to obtain stable Q characteristics with conventional BMT materials without mass productivity. In particular, although it is necessary to adjust the predetermined resonance frequency temperature coefficient τf depending on the application, it is known that the BMT material has τf in the vicinity of +5 ppm / ° C., and τ f is adjusted because it is a single compound. The trick was difficult.

[0006] In view of the present situation of the conventional composite perovskite type compound, the present invention provides a ceramic having a uniform internal quality with Q, τf and εr characteristics equal to or higher than those of the conventional dielectric ceramic composition. An object of the present invention is to provide a dielectric ceramic composition for electronic devices, which has excellent sinterability and can be stably obtained by sintering.

[0007]

DISCLOSURE OF THE INVENTION The inventor of the present invention has conducted various studies on the composition of conventional BMT materials for the purpose of eliminating the drawbacks of the above composite perovskite type compound, and as a result, a specific trivalent metal ion is contained. As a result, it was found that a porcelain having a homogeneous internal property, excellent characteristics, and excellent sinterability can be obtained, and Ba (1 / 3Mg.2 / 3Ta) O ₃ −
It was found that the Sr (1 / 2Ga · 1 / 2Ta) O ₃ system has a high Q, and as a result of various studies on the composition for the purpose of adjusting the resonance frequency temperature coefficient τf, as a result, a The inventors have found that the temperature coefficient τf of the resonance frequency can be arbitrarily selected by changing the ratio of Ba and Sr, and completed the present invention.

[0008] The present invention, the basic composition XBa (1 / 3Mg · 2 / 3Ta) O 3 -Y (Ba Z · S
r _1-Z) (1 / 2Ga · 1 / 2Ta) O _3, and X, Y, and Z that limit the composition range are composed of a composition satisfying the following values: It is a thing. X + Y = 1 0.3 ≦ X <1 0.7 ≧ Y> 0 0 ≦ Z ≦ 1

[0009]

[Function] This invention is Ba (1 / 3Mg. 2 / 3Ta)
In _{O 3 -Sr (1 / 2Ga ·} 1 / 2Ta) O 3 system,
Ba and Sr at the A site of the complex-proposcite type compound
It was found that the resonance frequency temperature coefficient τf can be arbitrarily selected by changing the ratio of B site ions (1 / 3Mg · 2 / 3Ta) and (1 / 2Ga · 1 / 2T).
BM which was difficult to sinter by changing the ratio of a)
It has been found that the sinterability of T-based materials can be improved, dielectric properties such as Q value can be stably produced, and εr characteristics can be selected by changing the B site ion ratio depending on the application. X and Y of the equation are 0.3 ≦ X <1, 0.7 ≧
The reason for limiting Y> 0 is that when the X value is less than 0.3 and the Y value exceeds 0.7, the resulting dielectric ceramic composition is significantly deteriorated in Q value and also in temperature coefficient. This is also because when the X value exceeds 1 and the Y value is 0, the effect of improving the Q value is not observed, and 0.3 ≦ X <1, 0.7 ≧ Y>.
The range is 0.

By setting the Z value in the range of 0 to 1, the resonance frequency temperature coefficient τf can be arbitrarily selected.

The dielectric ceramic composition of the present invention is 10 GH
Q in z can be large from about 7,000 to 50,000, and τ f ≦ 30 ppm / ° C., ε r 24 to 27.
Therefore, it is possible to obtain ceramics with characteristics equal to or better than those of conventional dielectric ceramic compositions, and it is possible to stably obtain ceramics with a uniform internal quality even during firing, which is excellent in sinterability and can be manufactured in a short time. it can.

In the present invention, Mg is replaced by N.
Almost the same effect can be obtained by substituting divalent metal ions such as i ²⁺ , Co ²⁺ , Mn ²⁺ and Zn ²⁺ and alkaline earth ions such as Ca ²⁺ up to about 20 mol%.

[0013]

Example The raw materials were weighed so as to have the composition shown in Table 1, mixed-mixed in a ball mill, calcined at 1200 ° C. for 2 hours, and then pulverized again in a ball mill to an average particle size of about 1 μm. This crushed powder is pressure-molded, and 1500 ° C to 160 ° C.
It was fired at 0 ° C. to obtain a sintered body having dimensions of 9 mmφ × 20 mm.

About the obtained sintered body, 25 ° C, 10G
The relative permittivity εr, Q at Hz and the temperature coefficient τ f (ppm / ° C.) of the resonance frequency were measured, and the results are shown in Table 1.

The relative permittivity and Q in Table 1 are H
It was measured by the dielectric resonator method by Akki and Celeman et al.
f, the dielectric constant, and the temperature coefficient τ ε of the dielectric constant have the following relationship with the linear thermal expansion coefficient α of the porcelain. τ f =-◆ τ ε-α

As is clear from the results of Table 1, the dielectric ceramic composition according to the present invention has a temperature coefficient of resonance frequency
Wide range from around 0 to around + 20ppm / ℃, low loss,
It turns out that it is a high dielectric constant material.

[0017]

[Table 1]

[0018]

The dielectric ceramic composition according to the present invention is
Q at 0 GHz is 7,000 to 50,000, τ f ≤
30 ppm / ° C., ε r 24 to 27, which has characteristics equivalent to or better than those of the conventional dielectric ceramic composition, and it is possible to stably obtain a ceramic having a uniform internal quality even during firing. It has excellent sinterability and can be manufactured in a short time.

Claims (1)

(57) [Claims] 1. A basic composition XBa (1 / 3Mg · 2 / 3Ta) O 3 -Y (Ba Z · S
r ₁ -Z ₎ (1 / 2Ga · 1 / 2Ta) O _3, and X, Y, and Z that limit the composition range are composed of a composition satisfying the following values: Stuff. X + Y = 1 0.3 ≦ X <1 0.7 ≧ Y> 0 0 ≦ Z ≦ 1