JPH08225366A - Dielectric porcelain composition - Google Patents

Abstract

PURPOSE: To obtain a dielectric porcelain composition capable of being produced in a fine state by low temperature sintering and having excellent electric characteristics. CONSTITUTION: This composition is obtained by compounding Bi in an amount of 0.003-0.035mol in terms of Bi2 O3 and Mn of 0.0005-0.0050mol in terms of MnO2 to a basic composition of the formula (Ba1-x , Znx )O.n(Ti1-y , Siy )O2 , wherein x, y and n satisfy 0.05<=x<=0.25, 0.01<=y<=0.15 and 3<=n<=6, respectively.

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 1 mol of the basic composition in which n is 3 ≦ n ≦ 6, Bi is converted to Bi ₂ O ₃ and 0.003 to 0.035
Molar part, Mn converted to MnO ₂ 0.0005 to 0.
It is characterized by containing 0050 parts by mol.

[0005]

According to the dielectric ceramic composition of the present invention, 1000
Since it can be densified by firing at a low temperature of ℃ or less, it is possible to reduce power costs, furnace materials, sheaths, setters, and the like, and it is also possible to use inexpensive Cu, Ag, and the like as electrodes.
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, densification does not occur by firing at 1000 ° C. or lower. x
Is less than 0.05, densification does not occur by firing at 1000 ° C. or less, and if it exceeds 0.25, the Q value is extremely small.

When y is less than 0.01, densification does not occur by firing at 1000 ° C. or less, and when it exceeds 0.15, the Q value is extremely small. When Bi ₂ O ₃ is less than 0.003 parts by mole, it does not become densified by firing below 1000 ° C.
If it exceeds the molar part, the Q value is extremely small. If MnO ₂ is less than 0.0005 parts by mole, it will not be densified by firing at 1000 ° C. or less, and if it exceeds 0.0050 parts by mole,
Resistivity deteriorates.

[0007]

EXAMPLES Examples and comparative examples of the present invention will be described below. 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 to 120 in air.
It was calcined at 0 ° 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 0.3 μm.
The following uniform particles were confirmed by SEM observation and a particle size distribution meter, and then dehydrated and dried to obtain a powder.

Then, the above powder and TiO ₂ , ZnO, S
iO ₂ , Bi ₂ O ₃ and MnO ₂ were weighed so as to have a predetermined ratio as shown in Table 1, wet-dispersed in a ball mill, dehydrated and dried, and then dried at 600 ° C. in air.
It was calcined at ˜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.
Granules are packed in a mold and hydraulic press presses 15mmφ x
It was molded to a height of 1 mm (molding pressure: 1 t / cm ² ), and fired in air at a temperature in the range of 900 to 1200 ° C. depending on the composition 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. Then, on both surfaces of these sintered bodies, In-
A Ga alloy was applied to form an electrode.

[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 under the conditions of 25 ° C. and 1 MHz. In addition, the temperature coefficient of capacitance is 2
Capacitance at 20 ° C (C
₂₀ ) as a reference, and based on this and the capacitance (C ₈₅ ) at 85 ° C., it was calculated based on the following equation. The resistivity is 150 ° C
It was calculated from the insulation resistance value and the sample size of the sample measured in 1.

[0011]

[Equation 1]

The above evaluation results and measurement results are shown in Table 1 above. As is clear from these results, the dielectric ceramic composition of the present invention can be densified at a firing temperature of 1000 ° C. or lower, and the electrode produced from the obtained sintered body is
The Q value was extremely high. In the examples and comparative examples, the composition after sintering was found to be almost the same as the composition at the time of compounding, as a result of ICP analysis of the sintered body after firing.

In the above embodiment, BaCO ₃ and Ti are used.
Raw material powder is obtained by mixing with O ₂ , calcination and crushing.
Similar results were obtained when a commercially available BaTiO ₃ having a particle size of 0.3 μm or less was used as the starting material instead of this raw material powder. Also, BaCO ₃ , Ti
O ₂ , ZnO, SiO ₂ , MnO ₂ and Bi ₂ O ₃ may all be mixed and dispersed at once and calcined. However, in this case,
Sinterability is slightly inferior. Also, instead of MnO ₂ , MnO,
It is also possible to use Mn ₃ O ₄ , MnCO ₃ , Mn (OH) _{2, and the} like.

[0014]

As described above, according to the present invention,
Since a densified porcelain composition can be obtained at a firing temperature as low as 1000 ° C. or less, it is possible to reduce power costs, furnace materials, sheaths, setters, etc., and use inexpensive Cu, Ag, etc. as electrodes. Will also be possible.

Claims (1)

[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
Bi is Bi with respect to 1 mol of the basic composition in which 5 ≦ x ≦ 0.25, y is 0.01 ≦ y ≦ 0.15, and n is 3 ≦ n ≦ 6.
0.003 to 0.035 mol part in terms of ₂ O ₃ , Mn is Mn
A dielectric ceramic composition containing 0.0005 to 0.0050 parts by mol of O ₂ .