JPS6042802A - Voltage dependent nonlinear resistor porcelain composition - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention absorbs or removes abnormal voltage, noise, static electricity, etc. generated in electronic and electrical equipment (BazCaySr.
l z y) This invention relates to a ceramic composition for obtaining a voltage-dependent nonlinear resistor containing TiO3 as a main component.

Conventional structure and its problems Traditionally, it has been used to absorb abnormal high voltage (hereinafter referred to as surge) and remove noise in various electrical and electronic devices.

SiC varistors, ZnO-based varistors, and the like having voltage-dependent nonlinear resistance characteristics have been used to eliminate sparks and the like. The voltage-current characteristics of such a varistor can be approximately expressed as follows.

I − (V/C) Here, Δ is the current, V is the voltage, C is a constant specific to the varistor, and α is the voltage nonlinear index.

The α of SiO varistors is about 2 to 7, and the α of some ZnO-based varistors is as high as 60. Such varistors have excellent performance in absorbing relatively high voltages such as surges, but because of their low dielectric constant and small specific capacitance, they are difficult to absorb low voltages below the varistor voltage (e.g. noise, etc.). ), and the dielectric loss angle (tan δ) is as large as 5 to 10%.

On the other hand, in order to remove these noises, the apparent dielectric constant can be reduced to 5×10 by appropriately selecting the composition and firing conditions.
Semiconductor ceramic capacitors with a size of about 4 to 6×10 4 and a tan δ of about 1 inch are used.

However, this semiconductor magnetic Samurai capacitor may break down if a current exceeding a certain limit is applied to the element due to a surge, etc.
It may no longer function as a capacitor.

For the reasons mentioned above, in electrical and electronic equipment, varistors are usually used in combination with capacitors and other parts (e.g. coils) for purposes such as surge absorption and noise removal.For example, noise filters are The configuration is like this.

Figure 1 shows a general conventional noise filter circuit, and Figure 2 shows a conventional noise filter circuit configured by combining a varistor, a capacitor, and a coil.
is a coil, 2 is a capacitor, and 3 is a varistor.

However, the configuration shown in FIG. 2 has the drawbacks of increasing the number of parts inside the device and contradicting the trend toward miniaturization of devices.

Purpose of the Invention The present invention eliminates the drawbacks of conventional surge absorption and noise removal as described above, and provides a composite function that has the functions of both a varistor and a capacitor and can perform surge absorption and noise removal with a single element. It is an object of the present invention to provide a voltage-dependent non-linear resistor ceramic composition which has the following characteristics and which exhibits less change in the characteristics of the non-linear index and varistor voltage due to the application of a surge.

Structure of the Invention In order to achieve this object, the voltage-dependent nonlinear resistor ceramic composition of the present invention has the following characteristics: (Bax CaySr+-X-y)
TiO3 (where X is a value in the range of 0001 to O-300 + 3' is a value in the range of 0.001 to 0300) to 99.995 to 9
6;000mo1%, Nb2O5, Ta2O,, CaO
21wo3. La2O3゜D72031 Nd2O31
Y2”31 0.0% of at least one metal oxide selected from the group consisting of Sm2O31Pr6O11
This relates to a voltage-dependent nonlinear resistor ceramic composition containing 05 to 5.000 mo1%.

In addition, the above composition further includes components that contribute to improving the nonlinear index, such as Ag2O, Cub, B2O3, Al□03.
゜Co2O3, MnO□, Sin, , Na2Q
The present invention relates to a voltage-dependent nonlinear resistor ceramic composition prepared by adding 1% of at least one metal oxide selected from the group consisting of 09001 to 3°OOOmol.

Description of examples The present invention will be specifically explained below using examples.

SrCO3, BaCO3, CaC2O4, Ti, and 02 were weighed and blended to give the composition ratio shown in Table 1 below, and ground and mixed in a ball mill for about 12 hours. V pressure 4. . t/, < f
Temporarily mold to 80φxsoim. The above molded body is 120
It is baked at 0℃ for 4 hours, and then ground again for about 12 hours using a pole to become the main raw material (BazCaySrl zy
) TiO3 powder (hereinafter referred to as the first component) was prepared.

Next, Nh, 05', Ta2O3, WO3, Dy2
O3, La,,03°Y2O3,Nd,,03! -Ca
O2 powder (hereinafter referred to as the second component) and Ag2O, Cub,
B2O3, Al2O3, MnO2, 5in2. Na
, 0 powder (hereinafter referred to as the third component) was weighed so as to have the composition ratio shown in Table 1 below.

Next, the above first to third components were dry mixed for 12 hours, and
After granulation by adding about 10 wt% of a binder such as polyvinyl alcohol, press pressure i, o t/c
, 4 to form a disk shape of 10φ×1” mm.

After baking the above molded body in air at 1000°C for 2 hours,
Calcinate at approximately 1400°C for 2 hours in a reducing atmosphere of N2 (90%) + H2 (10 times), then heat again in air at 1200°C.
C. for 3 hours to obtain element 4 shown in FIG.

Next, electrodes 6, 6 were formed by applying a conductive paste such as silver to both surfaces of the element 4 and baking it at 560°C.

The characteristics of the device obtained by the above operations are shown in Table 2 below.

(Leaving space below) Here, the characteristic evaluation of the element as a varistor is the voltage-current characteristic formula % formula %10) (However, ■ is the current, ■ is the voltage, C is a constant specific to the varistor, and α is a nonlinear index. ) can be done by α and C in ). However, since it is difficult to accurately measure C, in the present invention, the varistor voltage per unit thickness (hereinafter V1 B) when a varistor current of 1 mA flows (hereinafter referred to as V1 B) Jf
(referred to as nm) and the value of α-1/Iog (V 1om1 rod * mA Characteristics as a varistor are evaluated based on the value of .Furthermore, characteristics as a capacitor are evaluated using the dielectric constant ε at a measurement frequency of 1KH2.The above data is based on the firing temperature and time of 1400℃ + 2 hours in a reducing atmosphere. The firing temperature and time were 1200° C. and 3 hours in air.

In addition, the change in the nonlinear index after the surge voltage is applied (
Δα) and the change in varistor voltage (ΔV) are calculated by connecting a 2.0μF capacitor to a 2xV DC constant voltage power supply, applying the charging energy of the capacitor to the varistor three times at 5 second intervals, and then Nonlinear index (α′)
, the varistor voltage (V') was measured, and the rate of change was calculated using the following equation.

α′−α Δα2□x1o, o (%) As shown above, (BaxCay & + x−y)T
iO3CI X and y are 0. Oo1 In the case of non-vortex, the variation in the nonlinear index α is large, and the nonlinear index α for the pulse
The rate of change Δα of the varistor voltage V and the rate of change ΔV of the varistor voltage V are large, and the pulse resistance characteristics are poor. Furthermore, if X and y exceed Q300, the nonlinear index will decrease and the pulse resistance will also deteriorate. In the case of o, oo1≦y≦0.300, the pulse resistance characteristics are not substantially improved and variations in characteristics become large.

In this way, the cutting pulse characteristics are as follows:
o.

Even if just one value deviates from the range, it becomes bad.

Furthermore, if the amount of the second component added is less than O,'OOs mol 4, sufficient valence control will not be achieved and the specific resistance of the element will increase, resulting in a decrease in both the nonlinear index and the dielectric constant. On the other hand, if the amount added exceeds 1% of 5.0OOIIIO, sinterability deteriorates.

If the amount of the third component added is less than 0.005 mol, the nonlinear index cannot be significantly improved;

When the mo amount exceeds 1%, sinterability deteriorates and various properties deteriorate.

In addition, although only some combinations of the second and third components were shown in the examples, it was confirmed that the same effect can be obtained if the combination of multiple substances is within the specified addition amount range. .

Effects of the Invention As described above, the porcelain composition of the present invention contains (BazCa, Sr, -x,)Tie, (However, 0.0
By using values in the range of 01≦X≦0.300.0.001≦y≦o, 3oO, the rate of change Δα of the nonlinear index α and the rate of change ΔV of the varistor voltage V with respect to pulses are significantly improved. , reliability for pulses is significantly improved. Furthermore, the nonlinear index can be further improved by adding a third component, and by combining the above-mentioned main component and the third component, an element with a large nonlinear index and excellent pulse resistance characteristics can be obtained.

Create a circuit as shown in Figure 4 using the above elements,
As a result of investigating the output situation for a person inputting noise as shown in FIG. 5, it was found that the noise could be suppressed as shown in output situation curve B in FIG.

In FIG. 6, 7 is an element of the present invention, and 8 is a coil.

1. The output condition of the conventional filter circuit shown in FIG. 1 is as shown by the output condition curve C in FIG. 6, and noise is not removed sufficiently. The conventional filter circuit including a varistor shown in FIG. 2 can obtain an effect similar to the circuit shown in FIG. It has the combined function of a varistor and a capacitor, and has excellent pulse resistance characteristics, so the conventional noise filter circuit has been simplified, and it has become smaller and smaller.
It contributes to high performance and low cost, and can be used for surge absorption and noise removal in various electrical and electronic devices, and its practical value is extremely large.

[Brief explanation of the drawing]

Figures 1 and 2 are circuit diagrams showing conventional noise filter circuits, Figure 3 is a sectional view of an element using the ceramic composition of the present invention, and Figure 4 shows the element of Figure 3. FIG. 6 is a circuit diagram showing the noise filter circuit used. FIG. 6 is a characteristic diagram showing the input noise and output noise conditions of the noise filter circuit of the present invention and the conventional noise filter circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person
1 m 1 Fig. 2 1 Fig. 3 Fig. 5 → Solid-liquid number CMHI)

Claims (2)

[Claims] (1) (BaXCaySrl,)(,-y),TiO
s (However, X is 0.001 to O-300, y is 0.0
01 to 0.300) to 99.995-95.
OOOmol %, Nb2O5゜'ra2051 C
e o, l W 03 + IA2o31 ”V2O
5l Nd2O3+Y2O3, 811203, Pr60
．． 1. A voltage-dependent nonlinear resistor ceramic composition containing 0.005 to 5·00 mol% of at least one metal oxide selected from the group consisting of . (2) (BaxCaySr,,x,)TiO3 (X is 0001~o, 300.y is 0.001~α30
value in the range of 0) to 99+994-92.000m01%
, Nb2O,. Ta20s r G602 + W “315%”, l
Dy2031 Nd2'', tY203.Sm2O
3, Pr60. At least one metal oxide selected from the group consisting of o, oos~s, o o o
m'o1%, mug20. CuO+ B,,03.
Al2O2゜co203. MnO□, Sin□,
At least one kind of metal oxide selected from the group consisting of Ha20 from 0-001 to 3. A voltage-dependent nonlinear resistor ceramic composition characterized by containing OOO mol %.