JPS593003B2 - Porcelain dielectric material for temperature compensation - Google Patents

Description

Detailed Description of the Invention The present invention relates to Nd_2Ti_2O_7, Ca2Nb_2O_
7, and Nd_2Ti_2O_7,C
a2Nb_2O_7, -Mg2XTi_26-2X04
-2X (0<x<1.0).

The present invention has a large dielectric constant, low dielectric loss, and can freely change the temperature coefficient of the dielectric constant over a wide range.
Moreover, the present invention provides a temperature-compensating ceramic dielectric material whose temperature coefficient 10 does not change over a wide temperature range.

Temperature-compensating porcelain 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.

Until now, materials of this type include SrTiO3, CaT
Main ingredients include i03, MgTiO3, ca2ro3, etc.■
However, in these materials, those with a small temperature coefficient of dielectric constant have a dielectric constant value of 30 to 1.
6, and 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 PFI/°C or more.

Further, those having a large temperature coefficient of dielectric constant F5 have a drawback that the temperature coefficient varies greatly with temperature. Therefore, La20 is one of the materials that compensates for these drawbacks.
3-TiO2-MgO based materials were developed (Japanese Unexamined Patent Publication No.
9-12400). In this system, the temperature coefficient 10 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.

No.5 That is, Nd_2Ti_2O_7, Ca2Nb
The system shown as _2O_7 and Nd_2Ti_2O_7
, Ca2Nb_2O_7, -Mg-xTi_22X04
By synthesizing a ceramic dielectric material of the system represented by -2 It has been discovered that this material can be an excellent temperature-compensating porcelain dielectric material that has a constant temperature coefficient of permittivity over a wide temperature range. Furthermore, it has been found that the composition can be fired at a relatively low temperature and is easy to manufacture. The effectiveness of the present invention will be explained below based on Examples.

Example 2 For ceramic dielectric materials composed of X (0<X<1.0), Nd2O3, TlO2, CacO3, Nb2O5
, MgO powder, Nd2Ti2O7, Ca2Nb
2O7-Mg2XTl2-2X04-2X (XOO)} and Nd2Ti2O7, C
For the porcelain dielectric material composed of a2Nb2O7, N
Powders of d2O3, TiO3, CacO3, and Nb2O3 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 1671 tm and
Firing was performed at 0C to 1450C 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 1 KHz.

The temperature coefficient is the dielectric constant value -3'C. O℃, 20℃, 55
It was measured at each temperature of 85°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. Among the results obtained, representative examples 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, Black 6, and Table 1 of 14-1 to 14-3, it is composed of a porcelain dielectric material composed of Nd2Ti2O7, Ca2Nb2O7, and <x1.0). Porcelain dielectric materials exhibit excellent properties such as high dielectric constant and low dielectric loss.

It is clear that by further adjusting the composition ratio, the value of the temperature coefficient can be adjusted in a very wide range from about +260 PP [11/0 C to about -500 PF/°C. Moreover, the change in temperature coefficient with respect to temperature is ±30 PIXI1
/°C or within ±10% of the temperature coefficient. On the other hand, in the composition range where Nd2Ti2O7 is less than 5 mol% and the composition range where Ca2Nb2O7 is 95 mol% or more and the composition range where z is more than 80 mol%, the temperature coefficient changes with temperature within ±30PP01/°C, or the temperature coefficient ]0% or less and the dielectric constant value t is a composition outside the scope of the claims of the present invention.

The conditions of 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. (1) Nd2Ti2O7, Ca2Nb2O7
In the binary system of (g) - α) Nd2Ti2O7, α
When expressed as Ca2Nb2O7, the value of α is O〈α〈0
．． A porcelain dielectric material for temperature compensation, characterized in that it has a composition that satisfies the conditions of 95.

In the three-component system of (0<x×1.0), α[Nd2Tl2O7], β[Ca2Nb2O7], γ
[-Mg2XTi2-2X04-2X] (α+β
+γ=1.0), the values of α, β, and γ are 0.05 and α<1.0, 0 and β and 0.95 and 0<γ, respectively.
A porcelain dielectric material for temperature compensation, characterized in that it has a composition that satisfies the condition of <0.8.

Claims (1)

[Claims] 1 Nd_2Ti_2O_7, Ca_2Nb_2O_7
In the binary system of (1-α)Nd_2Ti_2O_7
- A porcelain dielectric material for temperature compensation characterized by having a composition in which the value of α, expressed as αCa_2Nb_2O_7, satisfies the condition of 0<α<0.95. 2 Nd_2Ti_2O_7, Ca_2Nb_2O_7
, 1/2Mg_2xTi_2−_2xO_4−_2x(
α[La_2Ti
_2O_7]・β[Ca_2Nb_2O_7]・γ[1
/2Mg_2_xTi_2-_2_xO_4-_2_x
] (however, α+β+γ=1.0), then α, β
, the value of γ is 0.05≦α<1.0, 0<β<0, respectively.
．． 95. A porcelain dielectric material for temperature compensation, characterized in that it has a composition that satisfies the condition of 0<γ<0.8.