JPH01130405A - Dielectric porcelain composition - Google Patents

Abstract

PURPOSE:To obtain a dielectric porcelain composition which is low in loss and of a high dielectric constant by composing it with SrTiO3, CaTiO3, PbTiO3, Bi2O3, TiO2, and CuO and specifying its component ratio. CONSTITUTION:A composition is composed of SrTiO3, CaTiO3, Bi2O3, TiO2, and CuO. Its component ratio in wt.% is SrTiO3:20.0 to 27.5%, CaTiO3:6.0 to 26.0%, PbTiO3:12.0 to 26.0%, Bi2O3:19.0 to 32.0%, TiO2:8.0 to 15.0%, and CuO:0.05 to 0.5%. Thereby, the component of a specific conductivity within 500 to 1200, a low dielectric loss tangent in 1MHz alternating electric field of 2.5% max., a low rate of the temperature change of dielectric constant in a temperature range of -25 deg.C to 85 deg.C of within + or -5%, and a resistivity at 85 deg.C of 10<11>OMEGA.cm min. can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a dielectric ceramic composition with low loss and high dielectric constant.

<Conventional technology and its problems> Sr n Os -CaT has been used as a dielectric ceramic material with the purpose of low loss and relatively high dielectric constant.
LOs-PbTLOg Byes ”log, or Sr TL 03- r T, Os Pb n
A material containing Os -BL 20 s-pores Ot as a main component is used.

However, the temperature change rate of the relative permittivity of these materials is often as large as ±10% or more within the temperature range of -25°C to 85°C;
If it is within the range, the dielectric constant will drop to 1000 or less.

In addition, even though it is a low-loss material, the dielectric loss tangent in a 1 MHz alternating current electric field is as large as 2.5% or more, unless the dielectric constant is 1000 or less, and the power loss when high frequency and high voltage is applied is low. Quite large.

On the other hand, Sr TL Os Ca TL O3
-Pb TL 0s-aL2o 3 It was reported in Japanese Patent Publication No. 1983 that a material containing Tb Ot as the main component, to which cILO and other subcomponents are added, can solve the above-mentioned problems to a certain extent.
No.-51443 is known.

However, by adding CLLO, 85 °C
In a temperature range exceeding 100 mL, the resistivity decreases and dielectric breakdown is likely to occur at a relatively low electric field strength. Further, when the relative permittivity is limited to a range of 500 to 1200, a material is desired whose relative permittivity changes with temperature within ±5%.

<Objective of the Invention> In view of the problems of the conventional dielectric ceramic compositions described above, the present invention has been made to: - have a dielectric constant in the range of 500 to 1200 and a dielectric loss tangent in an AC electric field of +11 1 MHz; 2.
It is small at less than 5%.

(The temperature change rate of the dielectric constant is small within ±5% within the temperature range of 125°C to 85°C.

+31 Specific resistance at 85°C is 10110·α or more.

It is an object of the present invention to provide a dielectric ceramic composition having the following characteristics.

Means for Solving the Problems> In order to achieve the above object, the present invention
Os, Ca TL (h, PbTiO3, [1,, Om
, T, Oz, and CILO, whose component ratios are SrTiO3: 20.0 to 27.5% by weight, Ca
TiOs: 6. Om26.0%, PbTLO
x: 12.0-26.0%, BL20s: 19. Om
32.0%, Tlz: 8.0-15.0%, CLO:
0.05 to 0.5%, or in addition to these compositions, 5na2: 1.0 to 3.5%, manganese oxide 0.05 to 0.3% in terms of 11n02, Lh.
20 s, rare earth oxides such as NJ 203 at 0.1
This provides a dielectric ceramic composition containing ~0.6% of the additive.

<Operation> Sr TL O constituting the dielectric ceramic composition of the present invention
s, Ca TL (h, Pb T= O,, B= 20
3, T = Ot, CULO, etc., to explain the reason for limiting the composition range, Sr TL (h is 20.0 to 2
The content of 7.5% by weight is Sr Ti o! If the amount is outside this range, the dielectric constant will be 500 or less, and the temperature change rate of the dielectric constant will not be within ±5%.

If Ca TL 03 exceeds 26.0% by weight, the dielectric constant will be 500 or less, and if it is 6.0% by weight or less, the dielectric constant will be 1200 or more, and the dielectric loss at 1MHz will be 2.5% or more. Moreover, the temperature change rate of the dielectric constant does not fall within ±5%.

For PbTLOs, this amount is 26.0% by weight
If it exceeds 1,200, the relative permittivity will be 1200 or more, and the temperature change rate of the relative permittivity will not be within ±5%. Also 12,
If it is 0% by weight or less, the dielectric constant will be 500 or less.

If the amount of Bi20s exceeds 32.0% by weight, IMH
If the dielectric loss at z is 2.5% or more, and if it is 19.0% by weight or less, the temperature change rate of the dielectric constant will not be within ±5%.

■ If the amount of 02 exceeds 15.0% by weight, the dielectric loss at IMHz will be 2.5% or more, and if it is less than 8.0% by weight, a stable sintered body may not be obtained. Even if stable porcelain could be obtained, the dielectric constant would be less than 500, and the resistivity at 85°C would be 1011Ω・c! n or less, which is not preferable.

When the CILO suspension exceeds 0.51ffi%, the specific resistance at 85°C becomes less than 1011Ω・ctn, and when it becomes less than 0.05% by weight, the dielectric loss tangent at IMHz becomes more than 2.5%, and the relative dielectric constant Temperature change rate does not fall within ±5%.

Next, Sn OH and rare earth oxide (e.g. LIL203
,■,0. ) has the effect of increasing the resistivity at high temperatures, which was lowered by the addition of CILO.

However, when the amount of Sn Oe exceeds 3.5% by weight, the relative permittivity becomes less than 500, and the temperature change rate of the relative permittivity becomes ±5.
% or less.

Further, when the amount of rare earth element oxide exceeds 0.6% by weight, the dielectric constant becomes 500 or less.

Manganese oxide is 1M without significantly lowering the dielectric constant.
It has the effect of lowering the dielectric loss tangent at 'Hz, but -02
When the amount exceeds 0.3% by weight, the specific resistance at high temperatures decreases.

Next, the reason why the range of relative dielectric constant of the dielectric ceramic composition obtained by this invention is limited to 500 to 1200 is explained because automatic insertion of parts by machine is becoming popular.
In line with this, it became necessary to standardize the external shape of the parts. Along with this, it is no longer possible to obtain a wide range of capacitance using only one type of dielectric material. Therefore, in order to obtain a wide range of capacitance, it is necessary to prepare several types of dielectric materials with different dielectric constants.

For that purpose, the present invention limits the range of relative permittivity as described above.

<Example> Next, the present invention will be explained in detail using examples.

First, as raw materials 5rC03, CaCO3, Pb3O4
, ■, 08, Sn Oe, Bt 20s,
CLLO, MIICO3, La203, NJ2 (h
was used. These raw materials were weighed to give the crude products shown in Table 1. Next, the weighed raw materials were placed in a Shima Hot with alumina balls and mixed for 16 hours.

After dehydrating and drying the obtained slurry, it was placed in a box and heated to 900 ml.
It was calcined at ℃ for 2 hours.

This was placed in a polyethylene pot together with alumina balls and a binder, mixed for 16 hours, pulverized, evaporated to dryness, and granulated using a sieve.

The obtained powder was pressed into a diameter of 12 mm using a hydraulic press. ,, It was molded to have a thickness of 1.2 mm.

Note that the density of this molded body was 3.5 gJ.

This molded body was placed in a box and heated to 1100 to 1200℃ in the atmosphere.
It was baked at a temperature of 2 hours.

Silver paste was applied to both end faces of the sample thus prepared and baked at 800°C to form electrodes.

Regarding the sample thus obtained, the relative dielectric constant, dielectric loss tangent,
When we measured the temperature change rate of capacitance (maximum change rate and minimum change rate from -25°C to 85°C with 20°C as the standard) and insulation resistance value at 85°C, we obtained the results shown in Table 2. It was done.

Note that the dielectric constant and dielectric loss tangent were measured using an impedance analyzer at frequencies of 1 KHz and 1 MHz. In addition, the temperature change rate of capacitance is the capacitance change rate [1
The maximum and minimum values of 00×(C-C16°C)/C2o°C%1 were measured.

Sample numbers marked with * in the table are outside the scope of the claims of this invention.

Table 1 Table 2 <Effects of the Invention> As is clear from the above examples, according to the present invention, the dielectric loss tangent in an alternating current electric field of 1 Ml-12 is within the range of 500 to 1200 and the dielectric loss tangent is 2. It is as small as .5% or less, and the temperature change rate of relative permittivity is ± within the temperature range of 125°C to 85°C.
This makes it possible to provide a dielectric ceramic composition that exhibits a small value of 5% or less.

Claims (2)

[Claims] (1) SrTiO_3, CaTiO_3, PbTiO_
3. It is composed of Bi_2O_3, TiO_2, and CuO, and their component ratios are SrTiO_3: 20.0 to 27.5% by weight, CaTiO_3: 6.0 to 26.0%, PbTiO_3: 12.0 to 26.0% Bi_2O_3: 19.0-32.0% TiO_2: 8.0-15.0% CuO: 0.05-0.5% A dielectric ceramic composition. (2) In addition to the composition shown in claim 1, the weight ratio of SnO_2 is 1.0 to 3.5%, manganese oxide is 0.05 to 0.3% in terms of MnO_2, and rare earth elements are added. The dielectric ceramic composition according to claim 1, characterized in that 0.1 to 0.6% of an oxide is added.