JPS6153162A - Voltage depending non-linear resistor ceramic 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 is directed to SrT103, which absorbs or removes abnormal voltage, noise, static electricity, etc. generated in electronic and electrical equipment.
The present invention relates to a voltage-dependent nonlinear resistor ceramic composition for obtaining a voltage-dependent nonlinear resistor having f as a main component.

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

SiC varistors and Zno-based varistors with voltage-dependent nonlinear resistance characteristics have been used to eliminate sparks, etc.The voltage-current characteristics of such varistors are approximately expressed as follows: can be expressed.

1=(v/C)(L Here, engineering is the current, ■ is the voltage, C is a constant specific to risk, and α is the voltage nonlinear index.

The α of SiC varistors is about 2 to 7, and the α of some ZnO-based IJ stars is as high as 60. Although such varistors have excellent performance in absorbing relatively high voltages such as surges, their low dielectric constant and small specific capacitance prevent them from absorbing low voltages below the varistor voltage (e.g. noise). It has almost no effect on the absorption of , and the dielectric loss angle (tan δ) is as large as 5 to 10%.

On the other hand, to remove these low voltage noises, the apparent dielectric constant can be reduced to 5 by appropriately selecting the composition and firing conditions.
Semiconductor ceramic capacitors with a size of about X10' to 6X10' and a tan δ of around 1 inch are used.

However, such semiconductor ceramic capacitors break down or cease to function as a capacitor when a current exceeding a certain limit is applied to the element due to a surge or the like.

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 use this combination. It is structured like this.

Is Figure 1 a typical conventional noise filter circuit? Figure 2 shows the varistor, capacitor, and coil? A conventional noise filter circuit configured in combination is shown.

Here, 1 is a coil, 2 is a capacitor, and 3 is a varistor.

However, the noise filter shown in Figure 1 is vulnerable to surges, and the noise filter shown in Figure 2 has many parts and is relatively large, which contradicts the trend toward miniaturization of overall equipment and increases costs. It had its drawbacks.

Purpose of the Invention The present invention eliminates all of 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 our objective to provide a complete porcelain composition suitable for making metals with no risks.

Structure of the Invention In order to achieve the above object, the present invention uses 5rTiO3f of 93.000 to 99.995 mol %, with a Sr and Ti minor ratio of Sx/Ti = -1,060 to 0.950;
Y2O3 0.001-2.000 mol% and Co2
03to, 001 to 2.000 mol%, and CuO'i
0.001~1.000Mo#% and Aq2゜2o
,oo 1 to 1.000 mol %, and Mno2woQ,
001 to 1.000 mol% of the voltage dependent nonlinear resistor ceramic composition, and the atomic ratio of Sr and Ti is S
r/Ti == 1.050~0.960 (7) S
rTio3'l<91.000-99.994 mol% and Y2O3'e 0.001-2.000 mol%
and Co2O3wo, 001 to 2.000 molmol, C
uOffi 0.001-1. ooo mole% and Aq
20'i 0.001-1.000 mo/l.

and MnO□'i 0.001 to 1.000 mol%
and B2O3゜NiO, MoO2, BeO, Fe2O3
, AjL203, L i 20 , Cr2O3.

PbO, CaO, TlO2, P2O5, 5b203. Y
2O, at least one kind of oxide selected from the kanal group, in an amount of 0.001 to 2. The present invention relates to a voltage-dependent nonlinear resistor ceramic composition containing Oo○mol%.

DESCRIPTION OF EMBODIMENTS Examples according to the present invention will be specifically explained below.

<Example> Pulverized for a time, mixed, dried, crushed again, press pressure 1
．． Temporarily formed into 80φ×60t (lW+) at ot/crA.

The above molded body was fired at 11200°C for 4 hours, and then ground again for about 20 hours using a ball mill etc. to form the main raw material, 5rTi○.
3 was created.

Next, 5rTi○3. Y2O3, Co203, Cu
o, A(Y2O, MnO2 and B2O3, NtO,
MoO2, BeO, Fe2O3, Afi203゜"Lt
20. Cr2O3, PbO, CaO, Tt02. p2O
5,5b2O3. Weigh Y2O5 so that it has the composition ratio shown in Table 1 below, mix it in a ball mill etc. for about 12 hours, and after drying, add about 10 wt% of an organic binder such as polyvinyl alcohol based on the total weight and granulate it. After that, it is formed into a disk shape of 10φ×1t (r) with a press pressure of 1 and Ot/crIl.

- After firing the above molded body in air at 1000°C for 2 hours, it was fired in a reducing atmosphere of N2 (oo%) +) (2 (10%)) at about 14QO°C for 2 hours, and then again in air. 12
After firing at 00° C. for 3 hours, a device 4 shown in FIG. 3 was obtained.

Next, electrodes 5 and 6 were formed by coating conductive paste gold such as silver on both surfaces of the element 4 and baking it at 660°C.

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

Table 2 is shown below in the margin. Here, the characteristic evaluation of the element as a varistor is the voltage-current characteristic formula % formula % described above. (However, I is the current, ■ is the voltage, C is a constant specific to the varistor, and α is It can be done by α and C in K (linear index). However, since accurate measurement of C is difficult, in the present invention, the value of the varistor voltage (hereinafter referred to as V, mA/m) per unit thickness when 1 mA of varistor current k flows, and α = 1 /20q (■10mA/v1m8)
(However, Vlo 011 A is the varistor voltage when the varistor current is flowing to 10 m, and VlrxxA is 1 mA.
The characteristics of the varistor are evaluated based on the value of the varistor voltage (when the varistor current is applied).

In addition, the characteristic evaluation as a capacitor was performed at a measurement frequency of 1kHz.
The dielectric constant ε at x and the dielectric loss angle tan δ are used.

As shown above, the essentially required characteristics of the varistor and capacitor are realized by the high resistance barrier produced at the grain boundaries of the element body.

Therefore, additives that increase the resistance only at the grain boundaries without increasing the resistance inside the grains are effective.

Y2O3, Co203IC as additives to 5rTi03
u○.

Aq20. By adding Mn02f, an element body having a relatively low varistor voltage and a high dielectric constant can be obtained.

Furthermore, these include B2O3, NtO, MoO2, BeO
, F e203°Lt20. An□03. Cr2O3,
PbO, CaO, Tio2. p2O5゜5b2O3. ■
By adding 2O5, α can be increased without changing the varistor voltage.
can be improved. The Sr/Ti 2 ratio greatly influences semiconductor formation, and outside the specified range, semiconductor formation is suppressed and the dielectric constant becomes small.

Moreover, if the amount of each additive is less than the specified amount range, no effect will be shown, and if the amount exceeds the specified amount range, the varistor voltage will increase rapidly and the dielectric constant will decrease, which is not desirable.

In the literature and examples, only the negative part is shown for combinations of additives, but it has been confirmed that any combination has the same effect as long as it is within the specified range.

As described above, according to the present invention, it is possible to simultaneously obtain the functions of both a varistor and a capacitor.

In the conventional filter circuit shown in FIG. 1, the output situation curve C is obtained for the noise input A shown in FIG. 5, and the noise is not completely removed.

In the conventional noise filter circuit including a varistor shown in FIG. 2, the output situation curve B is obtained for the noise input A shown in FIG. 5, and noise is removed, but the number of components is large.
It is relatively large and costly.

Therefore, when a circuit as shown in FIG. 4 was made using the element according to the present invention, the noise input AK shown in FIG.
N, the output situation curve B was obtained, and the noise could be sufficiently removed.

In FIG. 4, 7 is an element according to the present invention, and 8 is a coil.

Effects of the Invention As described above, the element using the ceramic composition of the present invention has an unprecedented combined function of a varistor and a capacitor, and furthermore, it completely simplifies the conventional noise filter circuit, and has a small size, high performance, and low cost. It 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 drawings]

Figures 1 and 2 are diagrams showing conventional noise filter circuits, Figure 3 is a cross-sectional view of an element using the ceramic composition of the present invention, and Figure 4 is a noise filter using the element shown in Figure 3. FIG. 5, which is a circuit diagram, is a characteristic diagram showing the input noise and output status of noise filter circuits using element sounds according to the prior art and the present invention. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
figure! Figure 3 Figure 4 Figure 5

Claims (2)

[Claims] (1) The atomic ratio of Sr and Ti is Sr/Ti=1.050
~0.950 SrTiO_3 from 93.000 to 99.00.
995 mol% and Y_2O_3 from 0.001 to 2.00
0 mol% and 0.001 to 2.000 Co_2O_3
mol%, CuO 0.001 to 1.000 mol%,
0.001 to 1.000 mol% of Ag_2O and MnO
A voltage-dependent nonlinear resistor ceramic composition containing _2 in an amount of 0.001 to 1.000 mol%. (2) The atomic ratio of Sr and Ti is Sr/Ti=1.050
~0.950 SrTiO_3 from 91.000 to 99.00.
9949 mol% and Y_2O_3 from 0.001 to 2.0
00 mol% and Co_2O_3 from 0.001 to 2.00
0 mol%, CuO 0.001 to 1.000 mol%, Ag_2O 0.001 to 1.000 mol%, Mn
0.001 to 1.000 mol% of O_2 and B_2O_
3, NiO, MoO_3, BeO, Fe_2O_3, L
i_2O, Al_2O_3, Cr_2O_3, PbO,
CaO, TiO_2, P_2O_5, Sb_2O_3,
A voltage-dependent nonlinear resistor ceramic composition containing 0.001 to 2.000 mol% of at least one oxide selected from the group consisting of V_2O_5.