JPS593006B2 - Porcelain dielectric material for temperature compensation - Google Patents

Description

Detailed Description of the Invention The present invention provides Nd2Ti_2O7, Sr2Nb_2O_7,
-Mg_2_xTi_2_-_2_xO_4_-_2_
The present invention relates to a ceramic dielectric material of the system represented by x (0<X<1.0).

The present invention has a large dielectric constant, a small dielectric loss, and the temperature coefficient of the dielectric constant σ can be freely changed within a wide range.
The present invention also provides a temperature-compensating ceramic dielectric material whose temperature coefficient does not change over a wide temperature range. 5 Temperature-compensating porcelain capacitors are often used as circuit elements in communication equipment, color televisions, etc. In this case, they have a large dielectric constant,
It is always desired that the dielectric loss be small, and it is desired that the temperature coefficient be at any specified value and remain constant with respect to temperature10.

Until now, materials of this type include 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. I0 Therefore, as one of the materials that compensates for these drawbacks, La2O3
-TiO2-MgO based materials have been developed.

(Japanese Unexamined Patent Publication No. 49-12400) In this system, the temperature coefficient has been successfully reduced 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, Nd2Ti_2O_7, Sr2Nb_2O_7
, -Mg_2_xTi_2_-_2_xO4_-_2_
By synthesizing a ceramic dielectric material of the system represented by x (0 < It has been discovered that the present invention can be used as an excellent temperature-compensating porcelain dielectric material in which the temperature coefficient of permittivity is constant at 1f5 over a wide temperature range.

Furthermore, it has been discovered that the firing temperature is relatively low and the composition is easy to manufacture.

The effectiveness of the present invention will be explained below based on Examples.

Example Nd2Tl2O7, Sr2Nb2O7, -Mg2XTl2-2X04-2X (0<x1.0)
For porcelain dielectric materials composed of Nd2O3, Ti
Powders of O2, SrCO3, Nb2O5, MgO, and Nd2T1207, Sr2Nb207, -Mg2XTi
For ceramic dielectric materials composed of 2-2X04-2X (X10), Nd2O3, TlO2, SrCO3, Nb
Weigh the 2O5 powder according to each composition, mix it in a ball mill, filter it, dry it, and heat it at 1000°C to 1200°C.
, 2 hours.

After that, it was pressure-formed into a disc with a diameter of 16W11n, and
Firing was performed at 0°C to 1450°C for 1 to 2 hours. After baking silver electrodes on both sides of the obtained porcelain at 600°C, dielectric properties were measured under the following conditions. The dielectric constant and dielectric loss were measured using a capacitance bridge at a frequency of 1KH2. The temperature coefficient is the dielectric constant value -30℃, 0℃,
Measurements were made at 200C, 55C, and 85C, and the dielectric constant value at 20C was used as a reference. Here, the temperature coefficient was calculated according to the following formula. Representative examples of the results obtained are listed in Table 1. In addition, soil is indicated in the temperature coefficient column of Table 1 from -30℃ to 85℃.
It is shown that the temperature coefficient at each temperature up to ℃ is within the range of soil.

As is clear from Table 1, Nd2Ti2O7, l. O)
The porcelain dielectric material composed of has a high dielectric constant and low dielectric loss, showing excellent properties.

It is clear that by further adjusting the composition ratio, the value of the temperature coefficient can be adjusted over a very wide range from approximately +240 ppm/0C to approximately -800 pIrn/0C. Furthermore, the change in temperature coefficient with respect to temperature is ±30 ppm/℃.
or within 10% of the temperature coefficient.
On the other hand, in a composition range in which Sr2Nb2O7 is more than 70 mol%, the condition that the change in temperature coefficient with respect to temperature is within ±30 ppm/°C or within ±10% of the temperature coefficient is not satisfied.

Also -Mg2Ti2-2X04-2X (0kuXku1.0
) is more than 80 mol%, the change in temperature coefficient with temperature is ±30 ppm/°C or ±1 of the temperature coefficient.
The condition that the dielectric constant is within 0% 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.

-Mg2XTl2-2X04-2X (0x<1.0)
In the ternary system of α[Nd2Tl2O7] and β[Sr
When expressed as 2Nb2O7]・γ[-Mg2XTi2-2X04-yu] (Tax α+β+γ-1.0), α, β
, γ are 0 and α<1.0, 0<β<. 0.7
, 0<γ<(0.8).

Claims (1)

[Claims] 1 Nd_2Ti_2O_7, Sr_2Nb_2O_7
, 1/2Mg_2_xTi_2_-_2_xO_4_-
In the three-component system of _2_x (0≦x≦1.0) α[N
d_2Ti_2O_7]・β[Sr_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<1.0, 0, respectively.
A porcelain dielectric material for temperature compensation, characterized in that it has a composition that satisfies the following conditions: <β<0.7 and 0<γ<0.8.