JPS5858763B2 - dielectric composition - Google Patents

Description

[Detailed description of the invention] The present invention relates to dielectric compositions.

The purpose of this is to reduce dielectric wire ε), dielectric loss (tan
The object of the present invention is to provide a composition that significantly improves the temperature stability of δ) and ε and is suitable for a small-sized, large-capacity, high-stability capacitor material.

Compositions containing 5rTiO3゜CaTiO32MgTiO3 as main components are conventionally known as high-stability porcelain capacitor materials, but the dielectric loss (tanδ) and the temperature stability of ε are simultaneously improved while keeping the dielectric constant ε) at a large value. It was impossible to do so.

Attempts have been made to improve this by incorporating various subcomponents or synthesizing multi-element compositions.

Among them, the CaTi03-CaTiO3O6 composition maintains a large value of ε and has succeeded in significantly reducing the value of the temperature coefficient of ε.

However, in this case as well, the temperature coefficient of ε is O±25ppm/℃.
When rubbed to a degree of O, the value was only 80 or less.

Also 5rTt03 t CaT t03 * MgTt
In densifying a composition containing 03 etc. as a main component, 13
It is necessary to sinter at a high temperature of 00°C or higher, which increases the "variation" in custom orders and poses an obstacle to industrial mass processing.

By synthesizing a new acid, all of the above drawbacks have been removed.

That is, the composition of the present invention has a significantly large dielectric constant and a small dielectric loss and small temperature change in the dielectric constant.

Furthermore, it has become possible to provide a material that can be sintered at extremely low temperatures and made into porcelain, which reduces variation in properties and is suitable for industrial mass processing.

The present invention will be explained in more detail below based on an example of implementation.

Examples Unless otherwise specified, powders of K2CO3, B12O3, and Zn02Nb205 were used as starting materials for producing the porcelain of the present invention.

Note that all of the raw material powders used here have a chemical purity of 98% or more.

A predetermined amount of each powder was weighed and mixed in a ball mill.

After filtration and drying, the mixture was pre-baked in the air at 600°C to 900°C for 2 hours. After pulverization, the mixture was press-molded into a disc with a diameter of 20vtm and then fired at 00°C to 1350°C for 2 hours.

After baking silver electrodes on both sides of the resulting porcelain, dielectric properties were measured using the following conditions.

That is, the dielectric constant (ε) and dielectric loss (tan δ) were measured at a frequency of IKHz at room temperature (O).

Further, ε was measured at 0° C. to +120° C., and the rate of change of ε with temperature was determined.

Among the results obtained, representative examples are shown in the table.

The table shows the fourth invention (composition according to the fourth invention). [KNbO3]1-a When expressed as It is.

Note that Mn was used.

Listing the relationship between x, a and dielectric properties using MnCOs as the starting material for Its excellent dielectric properties improvement effect is preserved.

That is, X is limited to a range of 0.05 x≦1.00.

Claims (1)

[Scope of Claims] A composition represented by ,]3[KNbO3]1-a, where a and X are 0.20:S:a<0.95-0.05
A dielectric composition characterized in that it has a composition range ζ expressed as <x×1.00.