JPS62137806A - 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 Field of Application The present invention protects semiconductors and circuits from abnormal high voltage, noise, and static electricity generated in electrical equipment and electronic equipment (Ca x S r 1x ) y T l○3 (
(o, oo1≦X≦0.4, 0.950≦y<1.oo
o)l.

(Baasrl-a)bTi○3((o, 001≦a≦
o, 4. o, 96o≦b<1. ooo)l.

(MgcSrl-c)d TiO2((0,001≦C
≦0.4, 0.950≦a<1. ooo) 1 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 expressed approximately as shown in the following equation.

'I=(V/C)a Here, I 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 6Q. Such varistors have excellent performance in absorbing relatively high voltages, but because of their low dielectric constant and small capacitance, they cannot absorb low voltages below the varistor voltage or high frequencies (e.g. noise etc.) has little effect on the absorption of
Further, the dielectric loss tan δ is as large as 5 to 10%.

On the other hand, semiconductor capacitors with an apparent dielectric constant of about 5×10 5 and a tan δ of about 1% are used to remove these low voltage noises. However, such semiconductor capacitors can withstand voltages exceeding a certain limit due to surges, etc.
If a current is applied to the capacitor, it may be destroyed or no longer function as a capacitor. Therefore, in recent years, 5rTiO
s as a main component and has both varistor and capacitor characteristics, but it has all the necessary features such as low varistor voltage, high α, high dielectric constant, and high surge resistance. A product that satisfies these characteristics has not yet been obtained.

3 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.

The present invention aims to solve these problems and provide a voltage-dependent nonlinear resistor ceramic composition that satisfies all of the above characteristics.

Means for Solving the Problems In order to solve the above problems, in the present invention, (Ca, c
Srl,)y'rt○3((o, o○1≦X≦0.4
, 0.950≦y×1.000)).

(Baa 5r1-a)b TiO2((o, oo1≦
a≦0.4, 0.950≦b<1. ooo)l.

(MqC3r1.)dTi○3((Q, oo1≦C≦0
．． 4, 0.950≦d<1. ○○O) The main component is at least one of 1, Y2O3゜YF3, Nb
2O5, T a 205. At least one type of LA 203 is added at a concentration of 0.001 to 2. OOOmo 1%
, CO2O3.

0.001 to 6.000 mol% of at least one of Cu O and Ag 20, and 0.001 of Mq○
The aim is to solve the above problems by obtaining a voltage-dependent nonlinear resistor ceramic composition containing ~5.000 mol%.

Function Generally, in order to convert 5rTf○3 into a semiconductor, a semiconductor conversion accelerator is added and reduction firing is performed, but depending on the type of semiconductor conversion accelerator, this alone may not be sufficient to convert it into a semiconductor.

Therefore, Sr in 5rTi○3 should be replaced with other elements such as Ca and B.
Substitution with a, Mq, etc. causes distortion in the crystal structure and promotes semiconductor formation. In addition, Sr, Ca, Ba,
By making the proportion of Mg more Ti than the stoichiometric ratio, lattice defects are generated, further promoting semiconductor formation, and at the same time promoting grain growth.

Therefore, when 5rTi○3 and Sr are replaced with Ca, Ba, Mg, etc., and there is an excess of Ti, the microstructure and properties of the final sintered body are significantly different, and it is considered that they are different compositions. It will be done.

Next, CO203, Cu○, Aq20. Z r 02
By adding , these segregate at the grain boundaries, making the grain boundaries high in resistance and exhibiting varistor properties.

Furthermore, B2O3, NiO, MoO3, BeO, F
e2O3゜Li OCr OPbOCab, TiO
2, P2O5゜2 ν 2 3I Sb203. A12o3. (2) Addition of 206 Sult and solera segregate at grain boundaries, increasing the height of barriers formed at grain boundaries, improving varistor characteristics.

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

5rCOCaC0BaC0MgCO3,TiO2313
13+ was weighed so as to have the composition ratio shown in Table 1 below, mixed in a ball mill etc. for 50 hours, dried, and then heated to 1000°C.
Calcinate for 0 hours. 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 granulated by adding 10 wt% of a binder such as polyvinyl alcohol. After doing 1
．． 1t/, 10φ (axl (cm
)・Un) Form into a disk shape. Then 1000 in air
After heating at 2F Terama Temperature and 13If at 2F to remove the binder, heat at 1500C in a mixed gas of N2:H2=9:1.
Bake for 3 hours. 7Σ et al., the conductive paste such as Aq was baked in air at 1200°C for 5 hours, leaving the outer periphery on both planes of the resulting sintered body 1 shown in Figs. 1 and 2. Screen printed, baked at 600℃ for 6 minutes,
Form electrodes 2 and 3. Next, attach the lead wires by soldering and apply resin coating 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), and the surge resistance is V1 mA after applying a pulsed current (voltage when a current of 1rn, A is passed).
The evaluation is based on the maximum pulse current value when the change is within ±10%.

As shown above, the characteristics vary greatly by changing the composition ratio of the main components. Here, (CaxCr1.),
TiO3, (BaaSrl,)bTie3. (Mg,
5r1-C) dTie3's X, 7. a, b.

The range of a, d is defined as X, &, C is 0.0
If it is less than 0.01, no effect will be shown, and if it exceeds 0.4, grain growth and semiconducting will be suppressed and electrical characteristics will deteriorate. In addition, the display of the composition of the main component is for example (Cax 5r
1-1) A: Although shown as TiO3, this is S r T
103 as a basis, a part of Sr is replaced with Ca, and the atomic ratio of Ca and Sr to T1 is y.
) Also referred to as TiO x 1-xy
2-)-y I can do it. The same can be said of (Baa 5r1-a) b TiO3° (Mgc Sr1 ,) d TiO3.

If y, b, and ci are 1.000, lattice defects will not occur and there will be no effect of promoting semiconductor formation, and if they are less than 0.96, Ti will be excessive and Ti crystals will be formed and the structure will become non-uniform. Characteristics deteriorate.

As for additives, the second component is a semiconducting accelerator, and if it is less than 0.001 moe%, it does not show any effect;
When OOOmol% is exceeded, reoxidation is suppressed and the varistor voltage becomes low, but tan δ is large, α is small, and surge resistance is weak.

Also, 3rd. The fourth component segregates at grain boundaries and has the effect of increasing α, but if it exceeds 5.000 mol %, it causes an increase in varistor voltage, a decrease in dielectric constant, and a decrease in surge resistance.

In addition, the sixth component is particularly effective in improving α and surge resistance, but if it exceeds 6.000 m o 6%, it will cause high I.
This results in an increase in J-star voltage, a decrease in dielectric constant, and a decrease in surge resistance.

In this example, only some combinations of additives were shown, but it was confirmed that other combinations of additives had similar effects.

Effects of the Invention As described above, according to the present invention, it is possible to simultaneously satisfy the characteristics of a relatively low varistor voltage, a large dielectric constant, a large α, a small tan δ, and a large surge withstand capacity. It is also highly effective in absorbing sharp pulses and surges, and functions as a protective element for semiconductor products, making it extremely effective in practical use.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 and 2 are a plan view and a front view, respectively, of an element using a ceramic composition 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 (-Xianzhuanghe'), 3---, GT crossing back 2 Figure

Claims (2)

[Claims] (1) (Ca_xSr_1_-_x)_yTiO_3{
(0.001≦x≦0.4) (0.950≦y<1.0
00)}, (Ba_aCr_1_-_a)_bTiO_
3 {(0.001≦a≦0.4) (0.950≦b<1
．． 000)}, (Mg_cSr_1_-_C)_dTi
_O_3 {(0.001≦c≦0.4) (0.950≦
d<1.000)}
．． 000-99.997mol%, Y_2O_3, YF
_3, Nb_2O_5, Ta_2O_5, La_2O_
0.001 to 2.00 of at least one of 3.
0 mol%, 0.001 to 5.000 mo of at least one of Co_2o_3, CuO, Ag_2O
A voltage-dependent nonlinear resistor ceramic composition containing 0.001 to 5.000 mol% of MgO. (2) (Ca_xSr_1_-_x)_yTiO_3{
(0.001≦x≦0.4) (0.950≦y<1.0
00)}, (Ba_aSr_1_-_a)_bTiO_
3 {(0.001≦a≦0.4) (0.950≦b<1
．． 000)}, (Mg_cSr_1_-_c)_dTi
O_3 {(0.001≦c≦0.4) (0.950≦d
<1.000)} at least one type of 83.
000-99.996 mol%, Y_2O_3, YF_
3. 0.001 to 2.000 mol% of at least one of Nb_2O_5 and La_2O_3, Co_
0.001 to 5.000 mol% of at least one of 2O_3, CuO, and Ag_2O, and 0.00% of MgO.
001-5.000 mol%, B_2O_3, NiO,
MoO_3, BeO, Fe_2O_3, Li_2O, C
r_2O_3, PbO, CaO, TiO_2, MnO_
2, P_2O_5, Sb_2O_3, Al_2O_3,
0.001 of at least one type of V_2O_5
A voltage-dependent nonlinear resistor ceramic composition containing ~5.000 mol%.