JPH03201503A - Porcelain composition for voltage dependent nonlinear resistor - Google Patents

Abstract

PURPOSE:To improve the temperature characteristics and nonlinear coefficient of varister voltage by preparing a voltage nonlinear resistor of a porcelain composition containing specific first component as the main component of a porcelain and second and third components as metallic oxides at specific ratios. CONSTITUTION:At least one kind or more of metallic oxides selected from a group composed of Nb2O5, Ta2O5 and WO3 or a rare earth oxide R2O3 (where R represents at least one selected from Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) as calcium barium strontium zirconate titanate in formula are used as second components. At least one of metallic oxides selected from a group consisting of a substance obtained by converting the metallic oxides into an MO form (where M represents Mn, Co, Ni, Cu, Zn, Mg, Ca, Sr, Ba, and Pb), a substance acquired by converting the metallic oxides into an M'2O3 form (where M' represents Fe, Al, Cr, Sb, and Bi), a substance obtained by converting the metallic oxides into an M''02 form (where M'' represents 57, Ti, zr, and Sn) and V2O5 are employed as third components. A 90-99, 98mol% first component and the 0.001-5.000mol% second and third components are contained respectively.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides S r (1-x-y) BaXCa, (T
The present invention relates to a voltage nonlinear resistor ceramic composition containing i, -z Z rt ) 03 as a main component, and particularly to a voltage nonlinear resistor ceramic composition that has improved temperature characteristics of varistor voltage.

[Conventional technology]

Conventionally, various varistors have been used to absorb or remove noise generated in various electronic devices.

Among these varistors, the varistor whose main component is 5rTi03 (for example, see Japanese Patent Publication No. 55-49404) has not only a varistor function but also a capacitor function, so it is free from glow discharge, arc discharge, abnormal voltage, The absorption or bypassing effect of noise etc. can be effectively suppressed.

(Problems to be Solved by the Invention) The conventional devices as described above had the following drawbacks.

(1) Varistors whose main component is 5rTiOt exhibit a phenomenon in which the varistor voltage decreases as the temperature rises.

Therefore, the varistor voltage decreases due to an increase in ambient temperature or self-heating during noise absorption.

(2) When a varistor is used, a constant voltage value (voltage equal to or lower than the varistor voltage) is generally applied at all times.

Therefore, due to the decrease in varistor voltage as the temperature rises,
If the varistor voltage value reaches around the constant applied voltage value, there is a risk that an excessive current will flow through the varistor or, in the worst case, thermal runaway.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned conventional drawbacks and to improve the temperature characteristics of a varistor by not changing or increasing the varistor voltage when the temperature rises.

[Means to solve the problem]

In order to achieve the above object, the present invention is as follows.

(1) The first invention is calcium zirconate titanate barium strontium S r(1-x-y)
B aXCa, (T sl-, Z rJ O3 (however,
0.100<X≦0.999, 0.001≦Y≦0
．． 500, 0.010≦Z≦o, value in the range of soo)
(hereinafter referred to as 1st t?, minute) 90 to 99.98 mol%
On the other hand, niobium oxide Nb2O3, tantalum oxide TazO
6. Tungsten oxide WO2 or rare earth oxide Rz
Oz (where R is indium Y, lanthanum L a % cerium Ce % praseodymium Pr, neodymium Nd,
Samarium S m s Europium E us Gadolinium Gd, Terbium Tb, Dysprosium Dy1
Holmium HO% Erbium Er, Thulium T m%
0.001 to 5.000 mol% of at least one metal oxide selected from interbium Yb and lutetium Lu (hereinafter referred to as the second rffc component);
Converted to the form of O (where M is Mn, Co, N
i, Cuz Zns Mg, Cas Sr, Ba
, Ph), metal oxide converted to M"203 form (however, Mo is F 8% A j2, Crs Sbs S
i), metal oxide converted to M”02 form (however, M
''' is S x , T I SZr, Sn) and V2O
The voltage nonlinear resistor ceramic composition is characterized in that it contains 0.001 to 5.000 mol % of at least one metal oxide selected from the group consisting of 5.

(2) The second invention further adds O to the lithium oxide LizO1 potassium oxide to the ceramic composition of the first invention.
At least one oxide selected from the group consisting of sodium monoxide Nano, cesium oxide C5ZO1, and rubidium oxide Rb2O (hereinafter referred to as the 4th precept) at 0.
001 to 2.5 mol%.

[Effect]

Since the present invention is configured as described above, it has the following effects.

(1) In the first invention, the first component is the main component of the porcelain, which mainly contributes to the temperature characteristics of the varistor voltage, and the second component is the metal oxide, which mainly contributes to semiconductor formation. and
The third precept mainly contributes to improving the nonlinearity coefficient and the temperature characteristics of the varistor voltage.

Therefore, creating a porcelain &ll animal varistor containing the first, second, and third commandments not only improves the temperature characteristics of the varistor voltage, but also provides a varistor with an improved nonlinearity coefficient.

(2) In the second invention, the fourth precept mainly contributes to preventing deterioration of the varistor voltage and nonlinearity coefficient against surges.

Therefore, by adding this, the temperature characteristics of the varistor voltage are improved, and a varistor whose characteristics deteriorate less due to surge application is obtained.

〔Example〕

Hereinafter, the present invention will be explained in detail based on the drawings 1 to 3 and Tables 1 to 5.

Figure 1 is a cross-sectional view of a varistor, Figure 2 is a varistor voltage characteristic measurement circuit, and Figure 3 is a surge application circuit.
is porcelain, 2.3 is a silver (Ag) electrode, 4 is a varistor, 5 is a DC constant current source, 6 is an ammeter, 7 is a voltmeter, 8 is a DC constant voltage power supply, 9 is a voltmeter, IO is a resistor, 11 is a single-pole double-throw switch, 12 is a capacitor, and 13 is a thermostatic oven.

+11 Examples of the first invention are shown in Example 1 and Example 2.

(Example 1) As raw materials, 5rC03, BaC0,, CaC0,,7
' i 0 z , Z r Ot, Nbzos, Mn
After converting and blending C0= to have the composition shown in Table 1, and mixing for 10 to 20 hours using a ball mill,
Dehydrate and dry.

Thereafter, the mixture is pre-calcined at 1200° C. and mixed for 10 to 20 hours using a ball mill again. Then, it is dehydrated and dried again. The resulting material was granulated by adding 10 to 15% by weight of polyvinyl alcohol as an organic binder, and a molded rod having a diameter of 7 mm and a thickness of 1+n was prepared at a molding pressure of about 20 t/emu''.

These discs were
) in a reducing atmosphere at about 1350° C. for 4 hours to obtain semiconductor porcelain. Next, this was subjected to heat treatment (reoxidation treatment) at 1100° C. for 3 hours in air (or in an oxidizing atmosphere).

Thereafter, in order to investigate the characteristics of the above-mentioned porcelain, as shown in FIG. .3 was perfected and Ballista 4 was completed.

In order to evaluate the characteristics of this completed varistor 4, we will evaluate the varistor voltage ■6, the nonlinearity coefficient α, the temperature coefficient ΔVat of the varistor voltage ■1, the capacitance C, and the v
When the change rates ΔVIF and Δα2 of l and α were measured, the first
The results shown in the table (electrical characteristics section) were obtained.

To explain in more detail how to measure each of the above characteristics, the varistor voltage vl was measured using the varistor voltage characteristic measuring circuit shown in FIG.

That is, an ammeter 6 is connected between the DC constant current source 5 and the varistor 4, a voltmeter 7 is connected in parallel to the varistor 4, a current of 1 mA is passed through the varistor 4, and the voltage at that time is measured. The varistor voltage is V.

In addition to the voltage V, a current 1 of 10 mA is applied to the varistor 4.
The applied voltage VIO when 1° was applied was measured, and the nonlinearity coefficient α was calculated from the following equation.

In addition, the temperature change rate ΔVIT is determined by changing the constant temperature chamber 13 to 20°C and 85°C in the varistor voltage characteristic measurement circuit shown in FIG.
The varistor voltage vI1,s) was measured at 85° C. and was calculated from the following equation (2).

Vr<to> 85 20 Next, in order to simulate how the characteristics of the varistor 4 change when a sharp pulse of overvoltage, that is, a surge voltage is applied, the surge application shown in FIG. Use a circuit.

In this circuit, a voltmeter 9 is connected in parallel with a 2KV DC constant voltage power supply 8. Then, a 2.5μF capacitor 12 is connected to the DC constant voltage power supply 8 via a 5Ω resistor 10 and a contact 11a of a single-pole double-throw switch 11.
Connect varistor 4 to b.

Applying the charging energy of the capacitor 12 to the varistor 4 at 5-second intervals is repeated 5 times, and then the varistor, voltage VIP, and nonlinearity coefficient α2 are measured and determined using the circuit shown in FIG. ), (4), the rate of change of varistor voltage ΔVIF (%) and the rate of change of nonlinearity coefficient Δ
α, (%) was calculated.

(However, V9 and α are the varistor voltage and nonlinearity coefficient before surge application) ΔαP = X1Ot) (%)
-----------(41 Also, the capacitance of each sample < nF
) was measured at IKHz, DCIV.

In Table 1, sample No. 1 has a negative temperature characteristic (temperature change rate) ΔVIT of the varistor voltage, and sample No.
007.8.13.14.19 has a nonlinearity coefficient α of 7.
The rate of change of the varistor voltage is less than ΔVIPIO%, or the rate of change of the nonlinearity coefficient Δα exceeds −10%, which is outside the scope of the present invention.

That is, in Table 1, as shown in sample No. 081, B
If the molar fraction X of a is 0.1 or less, the temperature characteristics of the varistor voltage (the temperature coefficient ΔVl becomes negative.
When the molar fraction X exceeds 0.999, the nonlinearity coefficient α becomes less than 7, as shown in sample No. 7.

In addition, if the mole fraction Y of Ca is less than 0.001, the nonlinearity coefficient α will be less than 7, as shown in sample N018, and if the mole fraction Y of Ca exceeds 0.5, the sample N
o, as shown in 13, the temperature coefficient ΔVI of the varistor voltage
T becomes negative, and the rate of change of varistor voltage ΔV
The rate of change Δα of IF and nonlinearity coefficient α exceeds 110%.

Furthermore, if the mole fraction Z of Zr is less than 0.01, sample N
o, 14, the nonlinearity coefficient α becomes less than 7, and when the mole fraction Z of Zr exceeds 0.5, sample N
As shown in 0119, the rate of change of the varistor voltage ΔVIF
and the rate of change Δα of the nonlinearity coefficient α exceeds −10%.

Also, in Table 2, for the 1st tc, Nbz'
When the content of os is less than 0.001 mol% or exceeds 5.0 mol%, samples No. 20 and No.

As shown in Figure 27, the nonlinearity coefficient α is less than 7, and its rate of change Δα exceeds 110%.

Furthermore, if the MnO content is less than 0.001 mol% or exceeds 5.0 mol%, sample No. 28 or N
As shown in 0136, the nonlinearity coefficient α is less than 7, and the rate of change ΔVIF of the varistor voltage and the rate of change Δα of the nonlinearity coefficient exceed −1O%.

Therefore, as shown in Tables 1 and 2, the first precept (
Sr(1-x-y) BaxCay)(TL-tZrt
) 0x(0,100<X≦0.999, 0.
001≦Y≦0.500, 0゜01≦Z≦0.5
00) (in the formula, x, y, z are the mole fractions of the components) 9
9 to 99.998 mol%, second component 0.001 to 5.000 mol%, which contributes to semiconductor formation, and third component 0.001 to 5.000 mol%.
001-5. If the varistor is made of a porcelain U oxide consisting of ooo mole %, the temperature coefficient ΔVIT of the varistor voltage will be positive or O, and the nonlinearity coefficient α will be an excellent value of 7 or more.

In addition, by applying a surge voltage, the rate of change of varistor voltage Δ
The absolute value of VIF becomes small, 10% or less, and the absolute value of the rate of change Δα of the nonlinearity coefficient due to application of the surge voltage becomes small, 10% or less.

The following margin (Example 2) In the present invention, the second component is other than Nb, O, i.e., Ta2O6, WO3, L az Ox, CeO,
, N d 203, Pr60++, Y2O3, Eu
t O3, ErzO+, Dy, o3, G d z O3
, T b t 03, Ho, 03, Tl11203, Y
In order to confirm that the same good effect as described above can be obtained even if the metal oxide of at least one of b z O3, Luz03 and Sm,02 is substituted, SrCO3, BaCO,, CaCO as a starting material was used. :l, TiO2
, ZrO2, Nb2O5, Ta205, HO3, La
203, Ceoz, Nd2O2, Pr60++, yz
o*, Eu, 03, Er, O,, D31fO'i, Cd
t○5, Tb, 03, HO203, T++, O,, Y
b z O3, L ut O3, S s z O3 and C.

O, Cr2O3, SrCO3, N i OXF e 2
03, MnC01,5bzo, , B a COs, B
i t Os, Ca CO3, Y2O5, Ti1t, P
bO,Sing,ZnO,ZrO,,Mg,CO,,S
n Oz, AIl! At the time of final firing, the converted weights of On were blended so that the Mi precepts shown in Tables 3 and 4 were obtained, varistors were made in the same manner as in Example 1, and characteristics were measured in the same manner. The results are shown in Tables 3 and 4 (electrical characteristics section).

From Table 3, in the 21st y, except for Nb2O, Ta, O,
, WO3, La, 03, CeO2, N d t O:l
, Pr601. ,Y,O,,EL1203,Er2O3
, Dy2O3, GdtO3, 'rbzoa, HotO,
, Tm, O5, Yb, 03, LuzOs and 5I
Even if it is replaced with at least one metal oxide of 11203, the temperature coefficient ΔVat of the varistor voltage is positive or 0.
, the nonlinearity coefficient α becomes 7 or more, and the rate of change of the varistor voltage Δ■1F and the rate of change of the nonlinearity coefficient α Δα
It can be seen that the absolute value of , is less than 10%.

Furthermore, from Table 4, the third component is something other than MnO, that is, CO0SCrzO, 5rC03, N iO%Fez
O,,,sb,o3,Ba COz,Bi2O3,Ca
CO2, Y2O6, TSO□, PbO1SiO2,
ZnO.

It was confirmed that even if at least one oxide of ZrO2, MHCO3, SnO, Al2O, etc. was used instead, the same good results as above could be obtained as long as the amount added was within the above limited range.

(2) An example of the second invention is shown in Example 3.

(Example 3) As starting materials, 5rCOs, BaC0, CaC01
, Tie, , Z r Ot, N b z O s, WOl
, La2O2, Ce Oz, Na2O,, pr&O
r+, Y, 01, ErzO:+, Sm, O, and Co
OSN i O, M n COs, 5bxO: +, B
i2O3, pbo, S i Oz, M g CO3, A
l1tO, and LizO, NazOlK t O% C
St O % Rb 2 O was blended in terms of weight so that the compositions shown in Table 5 were obtained at the time of final firing, and varistors were made in the same manner as in Example 1 and their characteristics were measured in the same manner. The results are shown in Table 5 (electrical characteristics section).

As shown in sample No. 83 in Table 5, the fourth precept is 0.
If it is less than 0.001 mol%, the absolute value of the rate of change ΔVIF of the varistor voltage and the rate of change Δα of the nonlinearity coefficient is 2.
% and does not add the fourth commandment 1.2.3.
Since it is not recognized that it is particularly convenient compared to the case in Table 4,
No effect of adding the fourth component was observed.

In addition, as shown in sample No. 92, the fourth precept is 2.5
If it exceeds mol%, the nonlinearity coefficient α is small, less than 7, and the absolute values of the varistor voltage change rate Δ■1F and the nonlinearity coefficient change rate Δα exceed 2%,
It is outside the scope of this invention.

Therefore, as shown in Table 5, if the fourth component is added in an amount within the range shown in claim 2, the temperature coefficient 1 & (rate of change ΔVat) of the varistor voltage becomes positive or 0. , the nonlinearity coefficient α is an excellent value of 7 or more.

Moreover, the rate of change of varistor voltage ΔVl? It can be seen that the absolute value of the change rate Δα of the nonlinearity coefficient α is as small as 2% or less, and the surge resistance is superior to that of the first invention.

Margin below [Effects of the Invention] As explained above, the present invention has the following effects.

(1) The first invention not only solves the drawback of the conventional varistor mainly composed of 5rTi03, in which the varistor voltage decreases as the temperature rises, but also
An excellent voltage nonlinear resistor ceramic composition having temperature characteristics that does not increase or fluctuate the varistor voltage can be obtained.

(2) In the second invention, the rate of change ΔVIF of the varistor voltage when a surge voltage is applied is higher than that in the first invention.
and the rate of change Δα2 of the nonlinearity coefficient α is very small,
That is, a voltage nonlinear resistor ceramic composition with excellent surge resistance can be obtained.

l・-・Porcelain　　　　2・ 4-...Barista 6...-Ammeter 8-・DC constant voltage power supply 10-・Resistance 12... Capacitor 3-・Silver electrode 5.--DC constant current source 7-・-Voltmeter 9-Voltmeter 1-Single pole double throw switch 3-・- constant temperature bath

Claims (2)

[Claims] (1) (Sr(1-x-y)Ba_xCa_y)(Ti
_1_-_zZr_z)O_3 (however, 0.100<X
≦0.999, 0.001≦Y≦0.500, 0.01
≦Z≦0.500) (in the formula, X, Y, Z are the mole fractions of the components) 90 to 99.998 mol%
b_2O_5, Ta_2O_5, WO_3, or rare earth oxide R_2O_3 (where R is Y, La, Ce, Pr
, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er,
0.001 to 5.000 mol% of at least one metal oxide selected from the group consisting of at least one metal oxide selected from Tm, Yb, and Lu), and the metal oxide converted into MO form (where M is Mn, Co, Ni, Cu, Zn, Mg, Ca, Sr, B
a, Pb), metal oxide converted to M'_2O_3 form (M' is Fe, Al, Cr, Sb, Bi), metal oxide converted to M''O_2 form (however, M'' is S
i, Ti, Zr, Sn), and at least one metal oxide selected from the group consisting of V_2O_5 0.0
01 to 5.000 mol % of a voltage nonlinear resistor ceramic composition. (2) (Sr(1-x-y)Ba_xCa_y)(Ti
_1_-_zZr_z)O_3 (however, 0.100<X
≦0.999, 0.001≦Y≦0.500, 0.01
≦Z≦0.500 (in the formula, X, Y, Z are
Nb_2O_5, Ta_2O_5, WO_3, or rare earth oxide R_2O_3 (where R is Y, La, Ce
, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho,
At least one metal oxide selected from the group consisting of (at least one selected from Er, Tm, Yb, Lu) is 0.001 to 5.00 in each form.
0 mol% and the metal oxide converted to the form of MO (where M is Mn, Co, Ni, Cu, Zn, Mg, Ca,
Sr, Ba, Pb), metal oxide converted to M'_2O_3 form (where M' is Fe, Al, Cr, Sb, B
i), metal oxide converted into M"O_2 form (where M" is Si, Ti, Zr, Sn), and at least one metal oxide selected from the group consisting of V_2O_5 0.001~ 5.000 mol%, Li_2O, K_
0.001 of at least one oxide selected from the group consisting of 2O, Na_2O, Cs_2O, and Rb_2O
2.5 mol % of a voltage nonlinear resistor ceramic composition.