JPS593008B2 - Porcelain dielectric material for temperature compensation - Google Patents

Description

Detailed Description of the Invention The present invention provides La2Ti_2O_7, Nd2Ti_2O_7
・-Mg2xTi_2_-_2_x (However,
．． The present invention relates to a ceramic dielectric material of the type represented by 0).

The present invention is a temperature compensation device that has a large dielectric constant, a small dielectric loss, and can freely change the temperature coefficient of the dielectric constant over a wide range mainly in the positive region, and the value of the temperature coefficient does not change over a wide temperature range. A porcelain dielectric material is provided.

5 Temperature-compensating ceramic capacitors are often used as circuit elements in communication equipment, color televisions, etc. In this case, it is always desirable to have a high dielectric constant and low dielectric loss, and the temperature coefficient can be set to any specified value. , and it is desired to maintain a constant value with respect to temperature.

So far, this type of material has been used as SrTiO3, CaT
Compositions containing i03, MgTiO3, CaZrO3, etc. as main components have been used, but in these materials, the dielectric constant value 15 is 30 to 16 if the temperature coefficient of dielectric constant is small.
Furthermore, the temperature dependence of the temperature coefficient, that is, the change in the temperature coefficient with respect to temperature, was as large as ±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. Especially 2
0 Previously, porcelain dielectric materials with positive temperature coefficients had a limited range of temperature coefficients. Therefore, a La203-TiO2-MgO-based material was developed as one of the materials to compensate for these drawbacks (Japanese Patent Application Laid-Open No. 12400/1983).

In this system, the temperature coefficient b has been successfully reduced to almost zero, and the temperature dependence of the temperature coefficient has also been improved to some extent. However, it has been impossible to adjust the temperature coefficient depending on the purpose. The present invention improves these drawbacks.

That is, La2Ti_2O_7, Nd2Ti_2O_7
, -Mg_-_2_xTi_2_-_2_xO_4_-
By synthesizing porcelain dielectric materials of the system represented by _2_x (O-Ex x 1.0), it has a large dielectric constant, low dielectric loss, and a wide positive range of the 35 temperature coefficient of the dielectric constant. It has been discovered that the temperature coefficient of the dielectric constant can be freely varied within a wide temperature range, and the value of the temperature coefficient of the dielectric constant is constant over a wide temperature range, making it an excellent temperature-compensating porcelain dielectric material. Furthermore, it was also found that the firing temperature was relatively low and the composition was easily crushed. The effectiveness of the present invention will be explained below based on Examples.

Example 04- Regarding the porcelain dielectric material composed of 2X (0<x × 1.0), La2O3, Ti2, Nd2O3, MgO
powder of La, Tl2O7, Nd2Ti2O7,
Regarding the ceramic dielectric material composed of Mg2XTi2-2X04-2X (X=0), La2O3, Nd3O3
, TiO2 powder was weighed according to each composition, mixed in a ball mill, filtered, dried, and heated at 1000°C to 120°C.
Prebaking was performed at 0°C for 2 hours.

After that, it was pressure-formed into a disc with a diameter of 16 m1 and heated to 1300°C.
Firing was performed at ~1450°C for 1 to 2 hours. After attaching silver electrodes to both sides of the obtained porcelain at 600℃,
Dielectric properties were measured under the following conditions. The dielectric constant and dielectric loss are 1
Measurements were made using a capacitance splitter at a frequency of KHz. The temperature coefficient is the dielectric constant value -30℃, o℃, 2'C
, 55°C, and 85°C, and the dielectric constant value at 20°C was used as a reference. Here, the temperature coefficient was calculated according to the following formula.

↓1VVJ ↓=UJ↓u×= Representative examples of the obtained results are listed in Table 1.

In addition, the display 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, Lε2Ti207, Nd2T
i207-]1Mg2xT12-2X04-2X (0≦
The porcelain dielectric material composed of X1.0) has a high dielectric constant and exhibits excellent characteristics such as low dielectric loss. By further adjusting the composition ratio, the value of the temperature coefficient can be adjusted to approximately -2.
It is clear that it can be adjusted in a very wide range, mainly in the positive region, from about 20 ppm ZC to +260 ppm/C. Moreover, the change in temperature coefficient with respect to temperature is ±30pp.
It is within m/C or within ±10% of the temperature coefficient. In a composition range in which B is more than 80 mol%, the conditions that the change in temperature coefficient with respect to temperature is within ±30 ppm/C 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. 04i in a three-component system (0≦x≦1.0).

Claims (1)

[Claims] 1 La_2Ti_2O_7, Nd_2Ti_2O_7
, 1/2Mg_2_xTi_2_-_2_xO_4_-
In the three-component system of _2_x (0≦x≦1.0) α[L
a_2Ti_2O_7]・β[Nd_3Ti_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<1.0, 0, respectively.
A porcelain dielectric material for temperature compensation, characterized in that it has a composition that satisfies the following conditions: <β<1.0, 0<γ≦0.8.