JPS62179103A - Voltage-dependant nonlinear resistance porcelain compound - 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 Application Field The present invention protects semiconductors and circuits from abnormal high voltage, noise, and static electricity generated in electrical equipment and electronic equipment.Cax3
r1 zTi03 (0.001-xTiO3(0.0
01≦x≦0.4) B2LySr 1-yTiOs (
0.001≦y≦0.4) MgzSr 1-1l:10
5 (0.001≦z≦0.4) as a main component.

Conventional technology SiC varistors and ZnO having voltage-dependent nonlinear resistance characteristics have been used to absorb abnormally high voltages, remove noise, eliminate sparks, and counter static electricity in various electrical and electronic devices.
A type of barista was used. The voltage-current characteristics of such a varistor can be approximately expressed as follows.

I=(V/C,)" Here, engineering is current, ■ is voltage, C is a constant specific to the varistor, and α is a 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 60. Although such varistors have excellent performance in absorbing relatively high voltages, their low dielectric constant and small inherent capacitance prevent them from absorbing low voltages below the varistor voltage or high frequencies (e.g. noise etc.), and the dielectric loss -δ is as large as 5 to 10%.

Semiconductor capacitors with an apparent dielectric constant of about 6×10 and −δ of about 1% are used to remove these low-voltage noises. However, if a voltage or current exceeding a certain limit is applied to such a semiconductor capacitor due to a surge or the like, it will be destroyed or will no longer function as a capacitor. Therefore, in recent years, products that have 5rTi05 as the main component and have both varistor and capacitor properties have been developed. A product that satisfies all the characteristics has not yet been obtained.

Problems to be Solved by the Invention In order to protect semiconductors and circuits from noise and static electricity, it is necessary to simultaneously satisfy characteristics such as low varistor voltage, high α, dielectric constant, and high surge resistance.

Conventional varistors are designed to absorb high-voltage surges, so they are not effective against noise or static electricity caused by low varistor voltages, and their low dielectric constant makes them poorly responsive to sharp-rising pulses. It had such problems.

Means to solve problems The present invention aims to solve the above problems.

Gaxer j-x'rxo5 (0.001-xTiO
3 (0.001≦x≦o,,a).

Buyer 1-yT105 (0.001≦y≦0.
4).

MgzSr, -2Tio, (o, oo1≦z≦o, 4
) containing at least one type as a main component, Y2O3
, YF5.

At least one of Nb2O3, Ta205, and La2O5 in an amount of 0.001 to 2. OOOmoβ%,
Co2O3.

At least one of CuO and Ag2o is o, 0
01-6. o00mO71! %, MgO o, o01
The above-mentioned problems are attempted to be solved by obtaining a voltage-dependent nonlinear resistor ceramic composition containing .about.jooo mo.beta.%.

Generally speaking, in order to convert 5rTi05f into a semiconductor, a semiconducting promoter is added and reduction firing is performed, but depending on the type of the semiconducting promoter, the semiconducting may not proceed much with this alone.

Therefore, SrF of SrT process 03 and other elements such as Ga
.

Substitution with Ba, Mg, etc. causes distortion in the crystal structure and promotes semiconductor formation.

Therefore, 5rTiO5 and Sr (3a, Ba,
The microstructure and properties of the final sintered body are significantly different from those substituted with Mg or the like, and are considered to be different compositions.

Next, Co2O3, cuo, Mug20, ZrO
By adding 2, these segregate at the grain boundaries, making the grain boundaries high in resistance and exhibiting varistor properties.

Furthermore, B2O3, NiO, kAo05. BeO
.

Fe2O3, Li2O, Cr2O3, PbO, (to
, TiO2゜pzo5.5b205. k120.
, v2os segregates at the grain boundaries and increases the height of the barrier formed at the grain boundaries, thereby improving the varistor properties.

Example The present invention will be specifically described below with reference to Examples.

First, 5rGO3, caco5, BaCO2, Mg
Co5°TiO2 was weighed to have the composition ratio shown in Table 1 below, mixed in a ball mill for 50 hours, dried, and then calcined at 1000'C for 1 hour. Additives were weighed to the thus obtained calcined product so that the composition ratio was as shown in Table 1 below, mixed in a ball mill etc. for 24 hours, dried, and then
After adding IQwt% of a binder such as polyvinyl alcohol and granulating it, it was granulated with a press pressure of 1 ton/J.
Form into a disk shape of mmφX 1 mm t. after that,
After calcining in air at 1000'C for 2 hours to remove the binder, it was heated at 1600°C in a mixed gas of N2:H2=9:1.
'C. Bake for 3 hours. Furthermore, 1200'C in air
- Sintered for 6 hours, screen printed a conductive paste such as Ag, leaving the outer periphery on both planes of the resulting sintered body 10 shown in Figures 1 and 2, and fired at 600'C for 6 minutes. Form electrode 2.3. Next, the lead wires are attached using solder or the like and coated with resin such as epoxy.

The characteristics of the device thus obtained are shown in Table 2 below.

The dielectric constant is calculated from the capacitance at 1K [Iz], and the surge withstand capacity is the change in V+mA (voltage when 1mA of current is passed) after applying a pulsed current by ±10%. The evaluation is based on the maximum pulse current value when the value is within the range.

(Hereafter, extra white) Here, the main component CazSr1-xT103.

B2LySr1yT105, MgzSr1zT10
The range of x, y, z in 3 was defined as 0.001
This is because if it is less than 0.4, no effect will be exhibited, and if it exceeds 0.4, grain growth and semiconductor formation will be suppressed, resulting in deterioration of characteristics.

The second component has no effect if it is less than 0.001m0β%;
, ○○○mob%, the varistor voltage becomes too low and −δ becomes large, which is not preferable.

The 3.4th component has no effect if it is less than 0.001 mo1%, and if it exceeds ts, ooomo7i%, the varistor voltage becomes too high, the dielectric constant becomes small, and the surge resistance becomes small.

The sixth component has no effect if it is less than 0.001 mol%2
If it exceeds 5.000 mo1%, the dielectric constant will be low and the surge resistance will also be low.

Although this example shows only some combinations of additives, the inventors have confirmed that other combinations of additives have similar effects.

Effects of the invention As mentioned above, some of the Sr in 5rTiO5 is replaced with Ca.
, Ba, and Mg, the grain boundaries are reinforced, and large capacitance and high surge resistance can be obtained in a region where the varistor voltage is relatively low.

Further, by adding additives, it is possible to considerably improve α and surge resistance.

The porcelain composition obtained in this way has a relatively low varistor voltage, high α, dielectric constant, and surge resistance, and has excellent response not only to surge absorption but also to sharp-rising pulses such as noise and static electricity. It is particularly effective in noise absorption, and has extremely large practical effects.

[Brief explanation of drawings]

FIGS. 1 and 2 are a top view and a sectional view showing an element according to the present invention. 1... Sintered body, 2.3... Electrode. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
figure

Claims (2)

[Claims] (1) Ca_xSr_1_-_xTiO_3 (0.00
1≦x≦0.4)Ba_ySr_1_-_yTiO_3
(0.001≦y≦0.4)Mg_zSr_1_-_z
88.000 to 99.997 mol% of at least one type of TiO_3 (0.001≦z≦0.4),
Y_2O_3, YF_3, Nb_2O_5, Ta_2O
_5, at least one type of La_2O_3 is 0
．． 001-2.000 mol%, Co_2O_3, Cu
0.00 of at least one type of O, Ag_2O
1 to 5.000 mol%, MgO 0.001 to 6.0
A voltage-dependent nonlinear resistor ceramic composition containing 00 mol%. (2) Ca_xSr_1_-_xTiO_3 (0.00
1≦x≦0.4)Ba_ySr_1_-_yTiO_3
(0.001≦y≦0.4)Mg_zSr_1_-_z
83.000 to 99.996 mol% of at least one type of TiO_3 (0.001≦z≦0.4),
Y_2O_3, YF_3, Nb_2O_5, Ta_2O
_5, at least one type of La_2O_3 is 0
．． 001-2.000 mol%, Co_2O_3, Cu
0.00 of at least one type of O, Ag_2O
1 to 5.000 mol%, MgO 0.001 to 5.0
00mol%, B_2O_3, NiO, MoO_3, B
eO, Fe_2O_3, Li_2O, Cr_2O_3,
PbO, CaO, TiO_2, MnO_2, P_2O_
5. At least one of Sb_2O_3, Al_2O_3, and V_2O_5 from 0.001 to 5.000 m
A voltage-dependent nonlinear resistor ceramic composition containing ol%.