JPS593004B2 - Porcelain dielectric material for temperature compensation - Google Patents

Description

Detailed Description of the Invention The present invention provides Sr2Nb_2O_7, Ca_2Nb_2O_
7, -Mg2xTi_2-2xO_4-2x (but 0
<x<1.0).

5 The present invention provides a temperature-compensating porcelain dielectric material that has a large dielectric constant, a small dielectric loss, can freely change the temperature coefficient of the dielectric constant over a wide range, and does not change in temperature coefficient over a wide temperature range. It provides:

10 Temperature compensation porcelain capacitors are often used as circuit elements in communication equipment, color televisions, etc. In this case, it is always desired that the dielectric constant be large and the dielectric loss be small, and the temperature coefficient can be set to any specified value. It is desirable to maintain a constant value with respect to temperature.

Until now, materials of this type include SrTiO3, CaT
Compositions containing i03, MgTiO3, ca_2ro3, etc. as main components have been used, but these materials have a dielectric constant value of 2030 to 1 if the temperature coefficient of dielectric constant is small.
6, and furthermore, the temperature dependence of the temperature coefficient, that is, the change in temperature coefficient with respect to temperature, was large at ±60 pμm/°C or more.

Moreover, those having a large temperature coefficient of dielectric constant have the disadvantage that the temperature coefficient varies greatly with temperature. 25 Therefore, La_203 is one of the materials that compensates for these drawbacks.
-TiO2-MgO-based materials were developed (Japanese Unexamined Patent Application Publication No. 1983-1983)
-12400).

In this system, we have succeeded in reducing the temperature coefficient to almost zero, and the temperature dependence of the temperature coefficient has also been improved to some extent. However, it was impossible to adjust the temperature coefficient depending on the purpose. The present invention improves these drawbacks.

That is, Sr2Nb_2O_7, ca_2Nb_2O_
7. -Mg2xTi_2-2xO_4-2x (but 0
By synthesizing the ceramic dielectric material of the system represented by < It has been discovered that this is an excellent temperature-compensating porcelain dielectric material whose temperature coefficient of permittivity is -constant in the temperature range. Furthermore, it has been found that the firing temperature is relatively low and the composition is easy to manufacture. below,
The effectiveness of the present invention will be explained based on Examples.

For the porcelain dielectric material composed of the example (0×<1.0), SrcO3, Nb2O5, CacO3, TiO2, M
gO powder, Sr2Nb2O7, Ca2Nb2O
7. For ceramic dielectric materials composed of Mg2XTi2-2x04-2X (X=O), SrcO3, Nb2O
3. CacO3, TiO2 powder, SrcO3,
CacO3, -MgOTl2-2x04-2x (x=1
．． 0) for the porcelain dielectric material composed of SrcO3
, Nb2O5, CacO3, and MgO powders were weighed according to their respective compositions, mixed in a ball mill, filtered, dried, and prefired at 10000C to 1200C for 2 hours.

After that, it was pressure-formed into a disc with a diameter of 16 m and 71 L, and
"The firing was carried out at 1450° C. for 1 to 2 hours. After baking silver electrodes on both sides of the obtained porcelain at 6000C, dielectric properties were measured under the following conditions. The dielectric constant and dielectric loss were measured using a capacitance bridge at a frequency of 1 KHz. The temperature coefficient is the dielectric constant value -300C, 0℃
, 20°C, 55°C and 185°C.
It was determined based on the dielectric constant value at °C. Here, the temperature coefficient was calculated according to the following formula.

Representative examples of the results obtained are listed in Table 1. It should be noted that the value of 2 in the column of temperature coefficient in Table 1 indicates that the temperature coefficient at each temperature from -30°C to 85°C is within the range of 2.

As is clear from Table 1, the porcelain dielectric material composed of Sr2Nb2O7 exhibits excellent characteristics such as a high dielectric constant and low dielectric loss. It is clear that by further adjusting the composition ratio, the temperature coefficient value can be adjusted over a very wide range from approximately +230 PF1/°C to approximately -280 ppm/0C. Furthermore, the change in temperature coefficient with respect to temperature is within ±30PF/°C or ±10% of the temperature coefficient. On the other hand, Sr2Nb2O7 is 70 mol%
In a larger composition range, the change in temperature coefficient with temperature is within 30 PP [[I/℃ or ±100 of the temperature coefficient!
) is not satisfied.

Also -1Mg2XTi2-2X04-2X (0〈x〈
In the composition range where 1.0) is more than 80 mol%, the condition that the temperature coefficient change with temperature is ±30 ppIn/℃ or within 10% of the temperature coefficient and the condition that the dielectric constant value is 30 or more are not satisfied at the same time. . Based on the above, the composition range of the present invention is limited to the following composition range. (0x〈1
．． 0), α[Sr2Nb2O7], β[Ca2Nb2O7], γ
[-Mg2Tl22O42] (However, α+β+γ=1.
0), the values of α, β, and γ are respectively 0〈α
A porcelain dielectric material for temperature compensation, characterized in that it has a composition that satisfies the following conditions: <0.7, 0 x β <1.0, 0 x γ x 0.8.

Claims (1)

[Claims] 1 Sr_2Nb_2O_7, Ca_2Nb_2O_7
, 1/2Mg_2_xTi_2-_2_xO_4-_2
In the three-component system of _x (0≦x≦1.0) α[Sr_
2Nb_2O_7]・β[Ca_2Nb_2O_7]・
γ[1/2Mg_2_xTi_2-_2_xO_4-_
2_x] (however, α+β+γ=1.0), the values of α, β, and γ are 0<α≦0.7 and 0<β<
A porcelain dielectric material for temperature compensation, characterized in that it has a composition that satisfies the following conditions: 1.0, 0<γ≦0.8.