JPS5826074A - Dielectric ceramic composition - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dielectric ceramic composition having a high dielectric constant and a small change in dielectric constant with respect to temperature.

More specifically, the present invention relates to a dielectric ceramic composition characterized by a high dielectric constant, a small loss angle, and a small voltage dependence of the dielectric constant.

Conventionally, Ba
Although Ti0s-based ceramics are widely used in practical use, the larger the dielectric constant, the greater the temperature change in the dielectric constant. In other words, when the dielectric constant is approximately 4000 or more at a temperature of 20°C, the capacitance change rate is 140°C in the temperature range of 20 to 85°C.
% or more, and the dielectric constant changes greatly depending on the applied voltage, so it has been difficult to manufacture a small capacitor with a large capacity by utilizing the high dielectric constant. It's temperature and voltage3.

This is because the initial value of the capacitance had to have a large margin because the change caused by the change or the change over time was large.

The present invention has experimentally confirmed that the above-mentioned phenomenon occurs to a non-negligible extent especially in ceramic capacitors, and has developed a dielectric ceramic composition in which such a phenomenon hardly occurs. The purpose of the present invention is to provide a high-performance dielectric ceramic composition that can be used in a volume that is approximately one-sixth that of a barium-based dielectric.

The characteristics of the porcelain dielectric composition of the present invention are as follows.
5n032 to 10 wt%, the temperature characteristics can be changed freely by changing the proportion of the above composition, and it is an excellent material with a high dielectric constant, a small loss angle, and a high withstand voltage. It shows the characteristics.

Although 5rTiOs has been known for some time, its dielectric constant is as high as 320, and its temperature coefficient is -3200X 10 /'C.
It is publicly known that This material has conventionally been used as a temperature compensation material, but this material
By adding the three components 3.Bi203-TiO2 and Ca1n'3, we succeeded in increasing the dielectric constant and reducing the temperature change rate.

Still, it is very difficult to make good porcelain using the above-mentioned single materials, and the above-mentioned substances alone are worthless as a ceramic dielectric composition, which is the purpose of the present invention.

However, based on numerous experimental results, the present inventors found that 5rTiOs
-PbTiO3-BizO3@TiO2-Ca5nO
It has been discovered that a composition using an x-based solid solution can provide a porcelain dielectric composition that has not been available hitherto.

In the composition of the present invention, the use of the 5rTiOs component, which is already in a single solid solution, provides good dielectric constant and temperature change rate, and serves to produce reproducible porcelain. In addition, the SrTiO3 component is high 6, . Although it has the effect of improving the loss angle at 5 frequencies, if it is present in too large a quantity, it can also cause a decrease in the dielectric constant.

If a large amount of the PbTi03 component is included, the dielectric constant will increase, but this will cause an increase in the temperature change rate. Also, Bi2
If the O3/TiO2 components are contained in large amounts, they cause a decrease in the dielectric constant and also make it impossible to produce good quality porcelain.

The CaSnO3 component has the effect of minimizing the decrease in dielectric constant and improving the rate of temperature change significantly.
Conversely, when the Ca1n'3 component increases significantly, the dielectric constant decreases.

The functions of each component are shown above, but if one or two of these components are missing, there will be no effect at all in making the porcelain for the purpose, and the components within the range will gather together to produce the porcelain for the purpose. This produces good quality porcelain.

It should be noted that if the 5rTiO3 component exceeds 60 Wt%, the dielectric constant will decrease significantly, which is not preferable, and 35 wt%
If it is less than that, the high frequency loss angle will be poor. Furthermore, if the PbTiOs' component exceeds 36 wt%, the temperature change rate will deteriorate and the dielectric constant will increase, which is not preferable. On the other hand, if the PbTi03 component is less than 14 wt%, the dielectric constant decreases significantly, which is not preferable. Furthermore, Bi
When the 20s-TiO2 component exceeds 35 vrt%, the dielectric constant decreases and the sintering condition deteriorates, and when it is less than 15 wt%, the rate of temperature change deteriorates. If the Ca5nOs component exceeds 1wt%, this is undesirable because the dielectric constant decreases, and if it is less than 2vrt%, the effect of improving the temperature change rate becomes poor, which is undesirable.

Unfortunately, in the present invention, if Bi2O5 is less than TiO2, good porcelain cannot be obtained.

Still, 0.2 to 0.2~MnO2 is added as an additive to the above composition.
By adding within the range of 1.0 wt%, there is an effect of bringing the rate of change in capacity closer to the desired range, and an effect of improving the loss angle at high frequencies. Here, MnO2
If it is less than 0.2 wt%, the effect of improving the high frequency loss angle is poor, and if it is less than 1.0 wt%, it lowers the dielectric constant, which is not preferable. In particular, 0.4~o, sw
Addition of SiO2 within the range of 0.05 wt%
Adding within the range of 1 to 1 Owt% has the effect of stabilizing the temperature change rate, but if it is less than 0.05 wt 4, the temperature change rate on the high temperature side (+85°C) worsens, and 1.0
When it exceeds wt%, the rate of temperature change on the low temperature side (-25°C) deteriorates. And CeO2 from 0.05 to 0.4
By adding within the wt % range, the loss angle of high frequencies can be improved. Outside this range, the high frequency loss angle deteriorates.

In this example, 5rTiOs was used with a composition ratio of equimolar in calculation, but good characteristics could be obtained even if the ratio was shifted by around 0.6 mole.

Next, the details of an example implemented based on such conditions will be described below.

First, as a sample preparation process, first, equimolar 5rCO
s and TiO2, PbO and Ti0z, CaCO3 and S
nO2 respectively, then 1050'C~120
After being calcined at 0°C for 2 hours, it was crushed and sorted into various particle sizes. Thereafter, each material was mixed in the respective proportions as shown in Table 1 below (5rTiO5
, PbTiO3, and CaSnO3 were confirmed to be a single solid solution by X-rays).

In addition, an Elema heating element was used for firing. In addition, in order to prevent the mixing of impurities, wet mixing is performed using a urethane-lined pot mill and a urethane-lined ball, after which water is evaporated, and the final molding is performed using a 1.
A disk of 50 m was press-formed at a pressure of approximately 1Qo''t/clr.'The firing was then carried out in an electric furnace using an Elema heating element at a temperature of 110°C to 1260°C and maintained for 2 hours. The thus obtained ceramic elements were coated with a silver electrode solution on both the inner and outer surfaces, baked at 800°C, and their electrical properties were measured.

The measurement results are shown in Table 2 below.

Note that LazOs is used instead of Cθ02 component in Table 1.

Nd2O3, Pr6o11. Good properties can also be obtained using Y2O3 raw material.

(hereafter τγ et al.) 9,・-7 101, 11.

JP-A-5A-2EO74 (4) 1j, -.

In Tables 1 and 2 above, examples within the scope of the present invention are N
115 to 1IkL11, and the others are examples outside the range.

As is clear from the examples, good properties can be obtained with compositions within the scope of the present invention. In particular, No. 7 had a high dielectric constant, a low loss angle at high frequencies (IMHz), good temperature characteristics, and good humidity and high temperature load life.

Although oxides of MnO2 and CeO2 were used in this example, good characteristics can also be obtained by using carbonate raw materials in the components of the present invention.

As described above, the present invention provides a dielectric porcelain that has temperature characteristics with a small rate of change in capacity, has a high dielectric constant and a low loss angle, and has a good long life under load under humidity and high temperature, in a composition within the range. It is suitable for industrial mass production.

Claims (1)

[Claims] (1) sr'r1o that has become a single solid solution in advance
Using 3゜PbTiO3 and CaSnO3 components, 5rTi
Os 35-60”% + PbTioa 14-3
5 wt%, Ca5H032~1wt Chi and B12
0s @ A dielectric ceramic composition consisting of a TiO2 component of 15 to 36 vrt%. (21Bi2O3, Ti0z) The ratio is BizOs
1.0: Ti0z'Co ~ Bi2O32,0:
Bi2O5・T process 0 formed from the ratio of TiO21,0
A dielectric ceramic composition according to claim (1), comprising two components. (3) 5rTiO3 already in a single solid solution
. Using PbTiOs and Ca1n's components, 5rTi
Os a 5-60 vrt%, PbTiO314
~35 wt%, Ga1n's2~1ovrt% and Bi2O! ! a For 100 wt% of a composition consisting of 16 to 35 wt% of TiO2 component, MnO2
0,2in1 wt%, 5i020.05 P-0,
6vrt%, Cen2. la2's, Nd2
A dielectric ceramic composition characterized in that 0.05 to Q4 wt% of at least one of the following is added by external cutting.