JPS6153160A - 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: Industrial Field of Application The present invention relates to a voltage-dependent nonlinear resistor mainly composed of 5rTi○3, 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.

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, 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) CL Here, Δ is the current, ■ is the voltage, C is a constant specific to the varistor, and α is the voltage nonlinear index.

The α of SiC varistors is about 2 to 7, and the α of some ZnO-based varistors is as high as 50. 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).
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 6 by appropriately selecting the composition and firing conditions.
Semiconductor ceramic capacitors with a tan δ of around 1 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.

FIG. 1 shows a general conventional noise filter circuit, and FIG. 2 shows a conventional noise filter circuit constructed by combining a varistor, a capacitor, and a coil.

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

However, the noise filter shown in Fig. 1 is susceptible to surges, and the noise filter shown in Fig. 2 has many parts and is relatively large.
It had the disadvantage of high cost.

Purpose of the Invention The present invention eliminates the drawbacks of conventional surge absorption and noise removal as described above, and has the functions of both a varistor and a capacitor, and is a single element.7 Composite functions capable of surge absorption and noise removal. The object of the present invention is to provide a porcelain composition suitable for making a porcelain porcelain composition having a porcelain porcelain composition.

Structure of the Invention In order to achieve the above object, the present invention uses Sr with an atomic ratio of Sr and Ti of Sr/Ti=1.050 to 0.950.
93.000 to 99.995 mol% of T103,
0.001 to 2.000 mol% of Y2O3 and Co2
O3 is o, oo1-2.000 mol%, CuO is 0.
001-1,000 mol% and 0.00 Ag2O
1 to 1,000 mol%, SiC2 0.00
1-1. ○Ocg: Voltage-dependent non-linear resistor ceramic composition containing Ti, and the atomic ratio of Sr and Ti is /
T1 = 1, S r T I of 050-0.950
Os in 91.000 to 99.994 mol% and Y2O
3 in an amount of 0.001 to 2.000 mol%, and Co2O3 in an amount of 0.001 to 2.000 mol%. ○oO mol % and CuO 0. o0
1 to 1.000 molar ratio and 0.001 to 1 Ag2O
,000 mol, SiC2 0.001-1,00
0 mo/l/% and B2032MnO2, Ni○.

Mo03r B e○, Fe2O3, A12o3Li2
0. Cr2O3, ZrO2゜PbO, BaO, CaO,
MgO, TiO2, ZnO, P2O6, 5b2o3゜Y
The present invention relates to a voltage-dependent nonlinear resistor fi1 composition containing 0.001 to 2,000 moles of at least one oxide selected from the group consisting of 2O5.

Description of examples EXAMPLES The present invention will be specifically described below with reference to Examples.

<Example> S r Co s t T 102 was weighed so that the atomic ratio of Sr and Ti was Sr/Ti = 0.980, pulverized and mixed in a ball mill etc. for about 20 minutes, dried, and then pulverized again. , press king 1.0 shio 80φx s o' (
Temporarily mold into ++w). The above molded body was heated at 1200°C.
The mixture was fired for an hour and then ground again for about 20 hours using a ball mill or the like to produce S r TiOs as the main raw material.

Next, 5rTi○3t Y2O3t Co 20s t
Cuo t Ag2Ot S i02 t and B2
O3, MnO2, Nip, MoO2, Be09Fe20
3. Al2O3゜Li, O, Cr2O3, ZrO2,
PbO, B aOt CaO, MgO, T i○2゜z
nO2P2o6,5b2o3. Weigh v206 so that the composition ratio is as 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. After granulation, it is molded into a disc shape of 10φ x 1t using a press pressure of 1.0 mm.

The above molded body was fired in air at 1000°C for 2 hours, then in a reducing atmosphere of N2 (90%) + H2 (10%') at about 1400°C for 2 hours, and then again in air for 12 hours.
After baking at 00°C for 3 hours, element 4 shown in FIG. 3 was obtained.

Next, a conductive paste such as silver was applied to the side plane of the element 4 and baked at 550°C to form electrodes 5 and 6.

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

Margin below Here, the characteristic evaluation of the element as a varistor is the voltage-current characteristic formula % formula %) (where ■ is the current, ■ is the voltage, C is a constant unique to the varistor, and α is a nonlinear index). This can be done by and C. However, since accurate measurement of C is difficult, in the present invention, the varistor voltage per unit thickness (hereinafter referred to as V, mA/ra) when a varistor current of 1 mA is applied is
n) and a = 1/log(V1
0mA/V1mA) (However, ■1omA is 10mA
Characteristics as a varistor are evaluated based on the value of the varistor voltage when a varistor current of 71 mA is applied, and 71 mA is the varistor voltage when a varistor current of 1 mA is applied.

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

As shown above, the basically required varistor characteristics and capacitor characteristics are expressed by the high resistance barrier generated 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, C02Q as additives to S r TiOs
3. CuO.

Aq20. By adding SiO2, an element body having a relatively low varistor voltage and a high dielectric constant can be obtained.

Furthermore, these include B2O3, MnO2, N iO, Mo
O2, BaO.

Fe203JA1203. Li2Q, Cr2O3, Zr
O2, PbO9Ba○.

Cab, MgO, TiO2, ZnQ, P2O5, 5b2
03. Adding P2O5 can improve α.

Further, if the amount of each additive is less than the specified amount range, no effect will be exhibited, and if it exceeds the specified amount range, the varistor voltage will increase rapidly and the dielectric constant will decrease, which is not desirable. Furthermore, the Sr/Ti ratio greatly influences semiconductor formation, and outside the specified range, semiconductor formation is suppressed and the dielectric constant becomes small.

In addition, in the examples, the combination of additives is -
Although only part b is shown, it was confirmed that any combination can have the same effect as long as it is within the specified range.

As described above, according to the present invention, the functions of both a varistor and a capacitor can be obtained at the same time.

The conventional filter circuit shown in FIG. 1 does not sufficiently remove noise, as shown in the output situation curve C for the noise input A shown in FIG.

In the conventional noise filter circuit including the 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 it requires a large number of parts, is relatively large, and is expensive. becomes.

Therefore, when a circuit as shown in Fig. 4 was made using the element according to the present invention, the output situation curve B was obtained for the noise input A shown in Fig. 5, and the noise could not be sufficiently removed. Ta.

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 device using the ceramic composition of the present invention has an unprecedented combined function of a varistor and a capacitor, and also simplifies the conventional noise filter circuit, making it compact, 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 is a characteristic diagram showing input noise and output conditions of noise filter circuits using elements according to the prior art and the present invention. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 4 Figure 5 Number of dredges per lap (Mt-i7-)

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 SiO
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 at 91.000~95.
994 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 SiO
0.001 to 1.000 mol% of _2 and B_2O_3
, MnO_2, NiO, MoO_3, BeO, Fe_2
O_3, Al_2O_3, Li_2O, Cr_2O_3
, ZrO_2, PbO, BaO, CaO, MgO, Ti
O_2, ZnO, P_2O_5, Sb_2O_3, V_
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 2O_5.