JPH08225365A - Dielectric porcelain composition - Google Patents

Abstract

PURPOSE: To produce a dielectric porcelain composition capable of being produced in a fine state by low temperature sintering and having excellent electric characteristics by replacing a part of Ba with Zn and a part of Ti with Si in a BaO-TiO2 dielectric porcelain composition. CONSTITUTION: BaCO3 , TiO2 , ZnO and SiO2 are weighed out so that the composition expressed by the formula (0.05<=x<=0.25; 0.01<=y<=0.15; 3<=n<=6) is obtained, and the mixture is sintered. This mixture enables the production of a porcelain having the composition of the formula at a low temperature of <=1050 deg.C in a fine state. Further, the incorporation of Bi in an amount of 0.003-0.035mol in terms of Bi2 O3 or Mn in an amount of 0.0005-0.005mol in terms of MnO2 based on 1mol of the composition of the formula enables the production of a porcelain composition at further lower sintering temperature such as <=1025 deg.C in a fine state. Accordingly, this enables the reduction of the cost of electricity, a furnace material, a sagger, a setter, etc., and the use of a less expensive electrode made of Cu, Ag, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric porcelain composition, specifically a temperature compensating dielectric porcelain composition suitable for use in a laminated capacitor, a laminated LC filter, a dielectric resonator and the like.

[0002]

2. Description of the Related Art As a conventional dielectric ceramic composition used for a dielectric resonator or the like, for example, JP-A-57-6 is known.
As disclosed in Japanese Patent Publication No. 9607, BaO-xTiO ₂
100% by weight of the composition wherein 3.9 ≦ x ≦ 4.1 in
On the other hand, a dielectric porcelain obtained by adding 1 to 26 wt% ZnO and mixing and firing is known.

[0003]

However, in the above-mentioned conventional dielectric ceramics, unless the firing temperature is as high as 1200 ° C., it is difficult to obtain a dense ceramic, and the electric characteristics easily vary. Therefore, an object of the present invention is to provide a dielectric ceramic composition that can be densified at a low firing temperature and that has good electric characteristics.

[0004]

The dielectric ceramic composition of the present invention has the general formula (Ba _1-x , Zn
_x ) O.n (Ti _1-y , Si _y ) O ₂ and x is 0.05 ≦ x ≦ 0.25 and y is 0.01 ≦ y ≦
0.15 and n is 3 ≦ n ≦ 6. Bi is added to Bi ₂ with respect to 1 mol of the basic composition having the above composition.
It is characterized by containing 0.003 to 0.035 parts by mol in terms of O ₃ . Also, the basic composition 1 having the above composition
0.0005 to Mn converted to MnO ₂ with respect to moles
It is characterized by containing 0.0050 parts by mol.

[0005]

According to the dielectric ceramic composition of the present invention, the basic composition is 1050 ° C. or lower, and the basic composition containing a certain amount of Mn or Bi is lower.
Since it can be densified by firing at a low temperature of 025 ° C or less, it is possible to reduce the cost of electric power, furnace material, sheath, setter, etc.
It is also possible to use inexpensive Cu, Ag or the like as an electrode. Next, the reason for limiting the composition range of the dielectric ceramic composition of the present invention as described above will be explained. When n is smaller than 3 or larger than 6, 1050 ° C. or lower in the case of the basic composition or 1025 in the case of containing Bi or Mn in the basic composition.
Does not densify by firing below ℃. When x is less than 0.05, the basic composition is 1050 ° C. or lower, and the basic composition is B
When i or Mn is contained, it is not densified by firing at 1025 ° C. or lower, and when it exceeds 0.25, both in the basic composition and in the case where Bi or Mn is contained in the basic composition, Q
The value is extremely small.

When y is less than 0.01, the basic composition does not become densified by firing at 1050 ° C. or lower, or when the basic composition contains Bi or Mn at 1025 ° C. or lower, and exceeds 0.15. In addition, the Q value is extremely small both in the case of the basic composition and in the case of including Bi or Mn in the basic composition. When Bi ₂ O ₃ is less than 0.003 parts by mol, 102
If it is not densified by firing at 5 ° C. or lower, and if it exceeds 0.035 parts by mole, the Q value is extremely small. MnO ₂ is 0.0005
If it is smaller than the molar part, it will not be densified by firing at 1025 ° C. or lower, and if it exceeds 0.0050 molar part, the resistivity will be deteriorated.

[0007]

EXAMPLES Examples and comparative examples of the present invention will be described below. First, the basic composition represented by the above general formula will be described. BaCO ₃ and TiO ₂ were calculated using Ba and Ti and weighed in equimolar amounts, and these were dispersed in a ball mill using ZrO ₂ beads and water as a dispersion medium. Next, this dispersion is dehydrated and dried, and then 800-
It was calcined at 1200 ° C. for 4 hours. The calcined product was wet pulverized under the same conditions as the above dispersion, and the dispersed particles thus obtained had a particle size of 0.
After confirming by SEM observation and particle size distribution analyzer that the particles are uniform particles of 3 μm or less, they were dehydrated and dried to obtain a powder.

Next, the above powder and TiO ₂ , ZnO and SiO ₂ were weighed so as to have a predetermined ratio as shown in Table 1 and wet-dispersed in a ball mill.
It was dehydrated, dried, and calcined in air at 600 ° C. to 900 ° C. for 4 hours. This calcined product was wet pulverized, dehydrated and dried. Next, polyvinyl alcohol was added to this dried product and granulated with a 32 mesh screen. The granulated product is packed in a mold and molded by a hydraulic press into a size of 15 mmφ × height 1 mm (molding pressure: 1 t / cm ² ), depending on the composition, 900-
Firing was performed in the air at a temperature in the range of 1200 ° C. to obtain a sintered product having a desired composition. The degree of densification of the thus obtained sintered body was evaluated by an ink test. Next, an In-Ga alloy was applied to both surfaces of these sintered bodies to form electrodes.

[0009]

[Table 1]

In Table 1, the samples marked with * are comparative examples having compositions outside the scope of the present invention. The electrical characteristics of the obtained electrode sample were measured. The relative permittivity ε _r and Q value were measured using an LCZ meter under the conditions of 25 ° C. and 1 MHz. Moreover, the temperature coefficient of the capacitance is determined by putting these electrodes in a constant temperature bath, changing the temperature from 20 ° C. to 85 ° C., and using the capacitance (C ₂₀ ) at 20 ° C. as a reference.
It was calculated based on the following formula from the electrostatic capacity (C ₈₅ ) at 5 ° C. The resistivity was calculated from the insulation resistance value of the sample measured at 150 ° C. and the sample size.

[0011]

[Equation 1]

The above evaluation results and measurement results are shown in Table 1 above. As is clear from these results, the basic composition of the present invention can be densified at a firing temperature of 1050 ° C. or lower, and the electrode prepared from the obtained sintered body has a relative dielectric constant ε _r and The Q value was high. Next, in order to further contain Mn or Bi in the above basic composition, the powder obtained in the above example and TiO ₂ , ZnO, SiO ₂ and MnO ₂ were added.
Alternatively, Bi ₂ O ₃ was weighed so as to have a predetermined ratio as shown in Tables 2 and 3, and a sintered body was obtained according to the method described in the above example, and then an electrode was produced. The electrical characteristics of the obtained electrode sample were measured and are shown in Table 2 and Table 3, respectively.

[0013]

[Table 2]

[0014]

[Table 3]

In Tables 2 and 3, the samples marked with * are comparative examples having compositions outside the scope of the present invention.
As is clear from Table 2, in the case of the Bi-containing composition of the present invention, densification was possible at a firing temperature of 1025 ° C. or lower, and the relative dielectric constant and Q value were high. Further, as is clear from Table 3, in the case of the composition of the present invention containing Mn, densification was possible at a firing temperature of 1025 ° C. or lower, and the relative permittivity and Q value were high.

In the above Examples and Comparative Examples, the composition of the sintered body was found by ICP analysis of the sintered body after firing to be almost the same as the composition at the time of compounding. In the above example, BaCO ₃ and TiO ₂ were mixed, calcined,
Although the raw material powder was obtained by pulverization, the same result was obtained even when a commercially available BaTiO ₃ having a particle size of 0.3 μm or less was used as a starting raw material instead of the raw material powder. . In addition, BaCO ₃ , TiO ₂ , ZnO, SiO ₂
Alternatively, MnO ₂ or Bi ₂ O ₃ may be mixed and dispersed all at once and calcined. However, in this case, the sintering property is slightly inferior.
Also, instead of MnO ₂ , MnO, Mn ₃ O ₄ , MnC
It is also possible to use O ₃ , Mn (OH) _2, or the like.

[0017]

As described above, according to the present invention,
Since a densified porcelain composition can be obtained at a low firing temperature of 1050 ° C. or lower in the case of the basic composition and 1025 ° C. or lower in the case of containing Bi or Mn, it is possible to reduce the power cost, the cost of the furnace material, the sheath, the setter, etc. It is also possible to use inexpensive Cu, Ag, etc. as electrodes.

Claims (3)

[Claims] 1. A general formula (Ba _1-x , Zn _x ) O.n (T
i _1-y , Si _y ) O ₂ , and x is 0.0
A dielectric ceramic composition, wherein 5 ≦ x ≦ 0.25, y is 0.01 ≦ y ≦ 0.15, and n is 3 ≦ n ≦ 6. 2. The amount of Bi converted into Bi ₂ O ₃ is 0.003 to 0.035 with respect to 1 mol of the basic composition having the above composition.
The dielectric ceramic composition according to claim 1, wherein the dielectric ceramic composition is contained in a molar part. 3. Mn converted to MnO ₂ with respect to 1 mol of the basic composition having the above composition is 0.0005 to 0.00.
The dielectric ceramic composition according to claim 1, which contains 50 parts by mol.