JPH02107551A - Dielectric porcelain composition for electronic device - Google Patents

Abstract

PURPOSE:To stably obtain homogeneous ceramics having superior Q, tf and Er characteristics and inhibiting the evaporation of Zn by incorporating a specified trivalent metal ion. CONSTITUTION:Starting materials are wet-mixed in a ball mill, calcined at about 1,300 deg.C for about 2hr, pulverized, press-molded and sintered at 1,500-1,550 deg.C to obtain a dielectric porcelain compsn. for an electronic device having a basic compsn. represented by the formula (where 0.85<=X<1.0, 0<Y<=0.15, A is Ta or Nb and B is Sm or Yb), 5,000-9,000 Q at 9GHz, <=50ppm/ deg.C tf and 31-42 Er.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Application This invention relates to dielectric ceramic compositions for electronic devices, particularly,
For use in various devices that take advantage of the low loss and good temperature characteristics of ceramic compositions, including temperature compensation capacitors, direct reception of satellite broadcasting that takes advantage of the low loss in the SHF band, and da. Regarding dielectric ceramic compositions used for dielectric resonators such as Zn converters, microwave strip line substrates, etc., Zn in the composition can be controlled to the required value by containing specific trivalent metal ions. The present invention relates to a dielectric porcelain composition for electronic devices that is internally uniform and has excellent properties.

BACKGROUND TECHNOLOGY In general, as a dielectric ceramic composition used for SHF band 8, among perovskie type compounds, Ba (B4-A heat) type 03 (where A; Ta, Nb B, etc.) of the following composition has been used. ; divalent metal ions (Zn or one or more of Ni, Co, and Mn), complex probuskite-type compounds are widely used.

In other words, (1) Ba(Zn4-Taj)03-based material (2) Ba(Z
n4-Nb2/3) O3-based material, etc.

The characteristics such as high εr, high Q, zf=o, etc. required of the dielectric ceramic composition used in this SHF band are severe, and composition control is important in order to meet these characteristics.

In conventional dielectric ceramic compositions, composition control, especially control of Zn, is important because Zn contained in the composition easily evaporates, and during firing, Zn spreads and aggregates on the outer surface of the ceramic. It has been difficult to stably obtain ceramics with uniform internal properties because they tend to form so-called "skin", and it has been difficult to obtain ceramics with stable properties.

(Reference J, Am.

Ceram Soc, 68 [10] 546-51
(1985)) Purpose of the Invention In view of the current situation of conventional composite provskite type compounds, the present invention has been made to provide a porcelain composition having Q, If, and er properties equivalent to or superior to those of conventional dielectric ceramic compositions. Suppressing evaporation of Zn contained in the composition to facilitate composition control,
The present invention also aims to provide a dielectric ceramic composition for electronic devices that can stably obtain ceramics with uniform internal quality.

Summary of the Invention The present invention aims to eliminate the drawbacks of the composite provskite type compound and to control Zn in a dielectric ceramic composition. As a result, it was discovered that by incorporating specific trivalent metal ions, it was possible to control Zn in the composition to the required value and obtain porcelain that was internally uniform and had excellent characteristics. .

In this invention, the basic composition is XBa(Zn4・A2/3)O3−YSr(B4・A+
)03, and is a dielectric ceramic composition for electronic devices, characterized in that X and Y, which limit the composition range, satisfy the following values.

0.85≦X<1.0 0<Y≦0.15 However, A: Ta, Nb B; Sm, Yb Structure of the Invention In this invention, a preferred dielectric ceramic composition is: /3) O3-8r (Sm4
-Ta))03 series (2)Ba(Zn4/Nbi)03-
8r(Sm4・'1”a2/3)O3 system In this invention, the reason for limiting to 0.85≦X<1.0.0<Y≦0.15 is that the X value is less than 0.85, the Y value If it exceeds 0.15, the obtained dielectric ceramic composition will have a significant deterioration in Q value, a large deterioration in temperature coefficient, and an X value of 1.
If the Y value is 0 or more, no improvement effect on the Q value can be seen, so the range is 0.85≦X<1.0.0<Y≦0.15.

Effects of the Invention The dielectric ceramic composition of the present invention has a Q of 5,000 to 9,000 at 9 GHz. tr≦50ppm/”C1er
31 to 42, properties equivalent to or better than those of conventional dielectric ceramic compositions can be obtained, and even during firing,
Since the evaporation of Zn contained in the ceramic composition is suppressed to some extent, it is easier to control the composition, and it is also easier to prevent the segregation of Zn within the ceramic, making it possible to stably obtain ceramics with uniform internal quality. can.

In addition, in this invention, Zn is replaced by Ni"Coz+, M
Divalent metal ions such as n2+, Ca2+, Mg2+”J
Substituting up to about 20 mol/% with alkaline earth ions can provide almost the same effect.

The raw materials of the example were weighed to have the composition shown in Table 1, mixed in a ball mill, and calcined at 1300°C for 2 hours.
It was ground again in a ball mill to an average particle size of about 1 pm.

This pulverized powder was press-molded and fired at 1500° C. to 1650″C to obtain a sintered body with dimensions of 10 mmΦ×20 mm.

Regarding the obtained sintered body, the relative permittivity εr at 25°C and 9 GHz, Q, and the temperature coefficient of resonance frequency T f (pp
m/''C) was measured and the results are shown in Table 1.

Note that the relative dielectric constant and Q in Table 1 are Hakkian
d It was measured by the dielectric resonator method by Celeman et al., and the relationship between the temperature coefficient d of the resonant frequency, the dielectric constant, and the temperature coefficient 18 of the dielectric constant and the linear thermal expansion coefficient α of the porcelain is as shown in the following formula. There is.

f=-1/2tε-0 As is clear from the results in Table 1, the dielectric ceramic composition according to the present invention has a wide temperature coefficient of resonant frequency from around 0 to around +50 ppm/''C, and has low loss. , it can be seen that it has a high dielectric constant interest rate.

Margin below

Claims (1)

[Claims] 1 The basic composition is XBa(Zn1/3・A2/3)O_3-YSr(B1
/2・A1/2) O_3 and limits the composition range
A dielectric ceramic composition for electronic devices, characterized in that , Y satisfy the following values. 0.85≦X<1.0 0<Y≦0.15 However, A: Ta, Nb B; Sm, Yb