JPS6035313B2 - Porcelain composition for temperature compensation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a temperature-compensating ceramic composition having a high dielectric constant and a linear rate of change in dielectric constant with temperature.

Conventionally, temperature-compensating porcelain compositions have contained Mgo as a compound.
Ti02, LaTi03, La203・Ti○2, Sr
Titanates such as Ti03 are known, and in order to reduce the temperature coefficient and increase the dielectric constant, there are various combinations of these titanates such as Mg○・Ti02-CaTi03-based compositions and CaTi03-I203・Ti02-based compositions. Mg○・Ti
02 type composition (Jiko Sho 37-11333) and SrTi03-CaTi03-Bi203/Ti02 type composition are known as temperature compensating ceramic compositions. However, the biggest drawback is that if you try to reduce the temperature change rate of the dielectric constant, the dielectric constant at room temperature will decrease, and conversely, if you increase the yield rate while keeping the temperature coefficient small, the essential characteristics of a temperature compensation capacitor The linearity of the dielectric constant-temperature characteristic, which is a typical characteristic, was disrupted, and a remarkable melody was exhibited.

For example, SrTi03-CaTi03-Bi203・T
In the case of i02 type composition, the dielectric constant at room temperature is 150~
300 can be obtained, but the temperature coefficient is as large as -1000 to 13000 ppm/00, and 0 to 1800 ppm/00.
It is impossible to obtain one with a small temperature coefficient of °C,
Furthermore, when the temperature coefficient was reduced to about -800 to -1000 ppm/°C, significant non-linearity of the capacitance-temperature characteristics due to strong electrostatic properties appeared, making it impossible to put it to practical use as a ceramic material for temperature compensation.

The present invention was made to improve the above-mentioned drawbacks.
The present invention provides a temperature-compensating ceramic composition having a high dielectric constant of 250 or more and excellent linearity of temperature characteristics of the dielectric constant.

That is, in the present invention, SrTi03 is 62.11 to 70.
1% by weight, CaTi03 by 26.49-31.2% by weight, Bi203 by 1% by weight. Spot ~5.37% by weight, Ti02
Nb24 is added to the basic composition of 0.47 to 1.84% by weight.
．． SrTi03-CaTi03-
In the basic composition of Bi203/Ti02, the Curie point exists in the range of 60 to 80 qo, so the capacitance-temperature characteristics in the temperature range of -3000 to 1100 qo do not have linearity. It is characterized by moving and relaxing the Curie point to obtain a linear temperature change in dew yield rate. Temperature-compensating ceramic composition of the present invention and Nb2
The figure shows a comparison of the rate of change in capacity with temperature for those with no additives of Q and Y203, and curves 1 and 7 are
203 without additives, curves 19, 21, and 2.5 are examples of the present invention, and the linearity is clearly superior to that without additives. Hereinafter, a detailed explanation will be given based on examples. S
rT;03, CaTi03, Bi203, and Ti02 were weighed and blended to have the composition ratio shown in Table 1, and these basic compositions were used as 10 anchors, and further Nb205, Y20
3 was added in the range shown in Table 1 and mixed wet, and after drying the mixture, an organic binder was added and the particles were sized to form 16 side◇×0. It was pressure molded into a disk shape on the side of the phrase.

The compact was fired at 135,000 for 2 hours. A sample was prepared by adding a silver electrode to the fired body thus obtained.
Table 1 shows the measured values of the characteristics of the samples prepared by the above-mentioned method. In addition, the linearity of the temperature change rate of capacitance is -30
The difference between the capacitance (Ct) at each measurement temperature within the range of o0 to 185oo and the capacitance value at 20°C is 20q.
The value K divided by the capacitance value at o, that is, K = expressed in Miyake Jijuku, sample numbers 1 and 7 in Table 1 are basic compositions, and sample numbers 19, 21, and 25 are within the scope of the present invention. As shown in the figure, there is a clear difference in linearity between those with and without Liu material added, clearly demonstrating the effect of adding the auxiliary material. Table 1 In Table 1, sample numbers 1 to 7 have the basic composition of the present invention, and sample numbers 8 to 14 are outside the range of the basic composition of the present invention.

In addition, sample numbers 19 to 21, 23, and 25 are according to the present invention, and samples 15 to 18, 22, 24, 26, and 27 are outside the scope of the present invention, and are different from the basic composition of sample numbers 4, 5, and 6. , the temperature coefficient shows the smallest value of -604 to 703 ppm/℃, but as is clear from the figure, the change in capacity with respect to temperature does not show a straight line, indicating that it has the most nonlinearity. There is. The basic composition showing the most nonlinearity is SrTi0366.68% by weight, CaTi03
29.64% by weight, Bj2032.74% by weight, Ti0
20.94% by weight was selected and the effect of containing Nhiro 05 and Y203 was investigated.

As is clear from Table 1 and the figures, the range of compositional limitations in the temperature compensating ceramic composition of the present invention is due to the following reasons.

{1} When SrTi03 is less than 62.11% by weight, the temperature coefficient is as large as -1000 ppm/℃ or more, and 70
．． Similarly, if it exceeds 16% by weight, the temperature coefficient will be -1000p.
It becomes large at pm/℃ or more.

'2} When CaTj03 is less than 26.49% by weight, the temperature coefficient is as large as -1000 ppm/°C or more, and even when it exceeds 31.2% by weight, the temperature coefficient exceeds -1000 ppm/00.

{3' If Bi203 is less than 1.3% by weight, the dielectric constant will be low, and if it exceeds 5.37% by weight, the Q value will be extremely low, which is not preferable. '4' Also Ti02 is 0.47
If it is less than % by weight, the temperature coefficient is -100 pm/.

Exceeds 0, 1. If the amount exceeds the weight percentage of the box, the sintered body will be significantly fused, which is not preferable.

'5- If Nb205 is less than 0.20% by weight, the linearity of the rate of change in capacity with temperature is impaired above 6500%.

Moreover, if it exceeds 0.50% by weight, the dielectric constant and Q value will be low, which is not preferable. ■ If Y203 is less than 0.05% by weight, the linearity of the temperature change rate of the capacitance at temperatures above 6500 is impaired, similar to Nb205, and if it exceeds 0.2% by weight, the linearity of the temperature change rate is good, but It has a low dielectric constant Q and a large temperature coefficient of -100 pm/°C or more, which is not preferable.

As described above, the temperature compensating ceramic composition according to the present invention has Sr.
By adding Nb2Q and Y203 to the basic composition of Ti03, CaTi03, Bi203, and Ti02, linearity of the temperature change rate of capacitance is achieved without disturbing the properties such as temperature coefficient, Q value, and dielectric constant. It has excellent effects and has great industrial value.

[Brief explanation of the drawing]

The figure is a characteristic diagram showing the relationship between temperature and the rate of change in capacity. 7 is the basic composition of the present invention, and curves 19, 21, and 25 are examples of the present invention.

Claims (1)

[Claims] 1 SrTiO_3 is 62.11 to 70.16% by weight,
CaTiO_3 is 26.49-31.26% by weight, Bi
_2O_3 is 1.38 to 5.37% by weight, TiO_2 is 0.47 to 1.84% by weight, and 0.20 to 0.50% by weight of Nb_2O_5 and Y_
A ceramic composition for temperature compensation, characterized in that it simultaneously contains 0.05 to 0.20% by weight of 2O_3.