JPS5935127B2 - High dielectric constant magnetic composition - Google Patents

Description

[Detailed description of the invention] The present invention provides iron-lead tungstate [Pb2AW1/3)0
3] Monozinc lead niobate [Pb (Znl/3Nb2/3
)03] system.

Conventionally, barium titanate [BaT] has been used as a high permittivity dielectric material.
It is well known that products containing [iO3] as a main component are widely put into practical use.

However, the sintering temperature for products whose main component is BaTi03 is usually a high temperature of 13,000C to 1,400C, and especially in the case of multilayer capacitors, expensive internal electrodes such as palladium or platinum, whose main component is palladium or platinum, are used as internal electrodes suitable for this sintering temperature. It had the disadvantage of requiring the use of precious metals. Therefore, in order to make it possible to use inexpensive internal electrodes such as silver, there has been a strong demand for a dielectric material that can be sintered at a low temperature of 1000° C. or lower.

An object of the present invention is to provide a high dielectric constant ceramic composition that can be sintered at low temperatures, has low dielectric loss, and has high specific resistance.

As an oxide that has been reported to be able to be sintered at temperatures below 1000°C, there is a composite oxide material containing lead.
d, Nauk, Phys, 5erie, 1960, P.
P1275-1277,'' are available.

In this document, the material sintered at the lowest temperature is Pb(Fe2
There is AW1/3)03. The inventor examined the sinterability of this material and found that a dense sintered body could be obtained at temperatures below 1000'C. However, when evaluated as a dielectric material, it was found that the dielectric loss was large and the resistivity was small, making it unsuitable for practical use. Therefore, Pb(Fe2A) can be sintered at low temperature.
In order to take advantage of the features of W1/3)03 and further improve the drawbacks of this material, we added various components to (Pb(Fe2/3W1)
/3) We added a study to make it a solid solution in 03 as a high dielectric constant porcelain material.

As a result, Pb(Znl//3N
It has been found that the object of the invention can be realized by adding something expressed as b2A)03. That is, the porcelain composition of the present invention has Pb(Fe2AW1/3)0340
~80 mol% Pb(Znl/3Nb2/3)0360~
20 mol%, can be sintered at a temperature of 950° C. or less, has a dielectric constant of 1000 or more at room temperature, has small dielectric loss, and has high specific resistance.

The present invention will be explained in detail below with reference to Examples.

Examples As starting materials, lead oxide [PbO], iron oxide [Fe2O]
3], tungsten oxide [WO3], zinc oxide [ZnO
] and niobium oxide [Nb2O5], and were weighed to the blending ratio shown in Table 1.

Next, after wet mixing this in a ball mill, 70OO
Pre-baking was carried out at C-800°C. After pulverizing this powder, it was pressure-molded into a cylinder with a diameter of about 16 cm and a thickness of about 10 m7-L at a pressure of about 7 tons/c-d, and then heated at 830°C to 900°C.
It was sintered at 30°C. The obtained sintered body was cut into disks of approximately 0.5 Ttm, and then silver electrodes were baked onto the disks. Table 1 shows various properties of the porcelain composition thus obtained. Here, the dielectric constant and dielectric loss were measured at a frequency of 1 kHz. The specific resistance was measured by applying a direct current of 100 Ω. In addition, the temperature is 20
Measured at °C. As is clear from Table 1, the ceramic composition of the present invention has a high dielectric constant, low dielectric loss, and high specific resistance.

Moreover, it is an excellent composition that can be sintered at a low temperature of less than 950° C., and is particularly suitable as an inexpensive material for multilayer capacitors. Note that compositions in which the blending ratio x is less than 0.4 or more than 0.8 are not included in the present invention because the dielectric constant at room temperature is low because the single point of the chili is greatly shifted to the higher or lower temperature side than room temperature. do not have.

Claims (1)

[Claims] 1 Iron/lead tungstate Pb (Fe_2_/_3W_
1_/_3) O_3 and zinc/lead niobate Pb (Zn
A two-component composition consisting of _1_/_3Nb_2_/_3)O_3 was combined with Pb(Fe_2_/_3W_1_/_3)x(
Zn_1_/_3Nb_2_/_3)_1_-_xO_
A high dielectric constant ceramic composition characterized in that the blending ratio x is within the range of 0.4≦x≦0.8 when expressed as 3.