JPS62136802A - Oxide resistor - 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 relates to an oxide resistor, and particularly to an oxide resistor suitable for absorbing switching surges in circuit breakers and the like.

[Conventional technology]

Conventionally, aluminum oxide-clay-carbon compositions have been known as linear resistors for circuit breakers, and have a resistance value of approximately 400Ω and a circuit breaker switching surge withstand capacity of 200 Joules/ad (hereinafter referred to as J). /ad), a resistance temperature coefficient of 19×10-”07°C (20 to 250°C), and an operating temperature of 200°C.

Recently, as power transmission voltages have become higher, there has been a strong demand for linear resistors for circuit breakers to be smaller and lighter, so resistors should (1) have increased switching surge resistance; (
2) Although the temperature will rise if a switching surge is injected, the resistance value should have little variation even when exposed to high temperatures. (3) Materials with a small resistance temperature coefficient are required.

[Problem that the invention seeks to solve]

Conventional resistors are made by adding carbon to an aluminum oxide-clay system and sintering it in an inert gas atmosphere, so that the resistance value is controlled by the carbon content; (1) the density of the sintered body is low; Low opening/closing surge resistance.

(2) When exposed to high temperatures, the carbon that controls the resistance value is oxidized, resulting in large fluctuations in the resistance value; (3) and the temperature coefficient of resistance is large.

Incidentally, the use of a zinc oxide type resistor as a resistor for a circuit breaker is known from Japanese Patent Application Laid-Open No. 55-57219.

However, the requirements (1) to (3) above, especially the increase in switching surge resistance, have not been considered.

The inventor of the present invention has solved the above problem as a result of intensive studies on crystal grains of a sintered body forming a resistor.

The object of the present invention is to have a resistance of 40 to 1000 Ω·] and a circuit breaker with high switching surge resistance.

There is no change in resistance value even when exposed to high temperatures of 500℃ or more.
Moreover, it is an object of the present invention to provide an oxide resistor having a characteristic of having a small resistance temperature coefficient.

Furthermore, it is an object of the present invention that the temperature coefficient of resistance is -I×10-8Ω
An object of the present invention is to provide an oxide resistor having a resistance in the range from /°C to +I X i O-8Ω/°C.

[Means for solving problems]

The oxide resistor of the present invention includes crystal grains made of zinc oxide,
A composite oxide sintered body composed of crystal grains made of a zinc oxide compound of a metal or metalloid element other than zinc,
It is characterized in that there is no grain boundary layer between each crystal grain, which has a higher electrical resistance than the zinc oxide crystal grains. In addition, it is a composite sintered body of crystal grains made of zinc a chloride and crystal grains exhibiting an electrical resistance value of 200Ω to 3×10 × 8Ω, and there is no grain boundary layer with higher electrical resistance than zinc oxide crystal grains. This sintered body is characterized by being plate-shaped (including disc-shaped) and having electrodes formed on both end faces.

[Effect]

A grain boundary layer having the same electrical resistance value as the zinc oxide crystal grains may exist between each crystal grain, and a gap may exist between the crystal grains at a portion corresponding to the grain boundary. The case where there is a gap includes the case where no grain boundary layer exists at all. It is desirable that the crystal grains of the zinc oxide compound have a higher resistance than zinc oxide in the range of 200Ω to 3×1Q18Ω. Preferably, the zinc oxide compound is selected from the following chemical formula: ZnzT
iOz+ZnzSiO+, Zn7SbzOtzt
ZnzZrOa+ZnzSnO+. In order to form these compounds, the metal acid or metalloid element is titanium (T).
i), silicon (Si), antimony (Sb), zirconium (Zr), and tin (Sn). Bismuth (B1)
The use of is not recommended. This is because when Bi is used, a grain boundary layer with high resistance is likely to be formed.

The raw material for the sintered body is mainly zinc oxide (ZnO),
Sub-components include metal/metalloid oxides other than Zn○, such as titanium oxide (TiO2), silicon oxide (SiOz),
Antimony oxide (S b20il), T zirconium oxide (Z r 02 ), and tin oxide (SnOz) are used.

The structure of the sintered body of the present invention is characterized by the interrelationship of crystal grains, and its manufacturing method depends on the raw materials to be mixed. You will have to choose. The obtained resistor generally shows linearity, but
If nonlinearity is exhibited, it is effective to apply a high voltage to destroy the high-resistance portion, especially the grain boundary layer.

As a result of various studies on reducing the size and weight of circuit breaker resistors, the inventors found that (1) the resistor used has a resistance value of 40 to 4
000Ω・l, and the opening/closing surge withstand capacity is 400J-a &
Above, the temperature coefficient of resistance is ±lXl0-3Ω/℃ (20~5
(2) The resistance value change must be within ±10% even after exposure to high temperatures of 00°C or lower and 500°C or higher. It was discovered that the resistance of the resistor is affected by the specific gravity of the resistor. Therefore, the raw materials used for the resistor should be easy to sinter, the raw materials should react with each other to produce new crystal grains with different electrical resistance, and the resulting sintered body should have a high specific gravity. Therefore, we investigated the characteristics of a resistor whose basic components are zinc oxide, titanium oxide, and magnesium oxide, with additions such as antimony oxide, silicon oxide, zirconium oxide, and tin oxide. As a result, (1) the opening/closing surge withstand capacity is 800 J/cnf, which is approximately four times that of the conventional product, and (2) the temperature coefficient of resistance is significantly higher than the basic component zinc oxide (
(3) The resistance value changes from negative to positive depending on the content of magnesium oxide (MgO) in ZnO), titanium oxide (TiO2), and elemental magnesium oxide (MgO). , T x O2zMgO to antimony oxide (S bs O2) p silicon oxide (S x
It has been discovered that this can be improved by adding zirconium oxide (ZrO2), tin oxide (SnO2), etc.

As for the desirable composition of the resistor of the present invention, the basic composition is Zn065-94.8% and TiO24.7-94.8% in molar ratio.
20%, Mg00.2-15% is good.

Furthermore, 5b302v SiO2TZ is added to this basic composition.
rOz, at least one of the oxides of SnO2
．． It may be added in an amount of 06 to 11.7 mol%.

If the composition is at least T i O2 in the above composition range, the temperature coefficient of resistance becomes larger than ±lXl0-3Ω/°C, which is not desirable as a resistor for a circuit breaker. However, by containing T i 02, the switching surge resistance is significantly improved. The cause of this is Zn○ and Ti0 in the raw materials.
When sintered with
This is considered to be because 0Ω is slightly higher than the 10 to 50Ω of ZnO crystal and contributes to improving the density of the sintered body. Also, M
In the case of gO, the temperature coefficient is changed from negative to positive, and Ti0z
Similarly to the addition, the temperature coefficient of resistance becomes at least greater than ±I x 10 -8 Ω/°C than the above composition range. And if the composition exceeds the above range, the opening/closing surge resistance will be 4.
If it becomes smaller than 00 J/ad, it becomes unsuitable as a resistor for a circuit breaker. Furthermore, the additive 5bzOa +5iOz, Z
In the case of rO2 and Snow, if the composition exceeds the above range, the resistance value will be higher than 4X10"Ω・l, and the switching surge resistance will decrease, making it unsuitable for use as a circuit breaker resistor. The reason for this is Think as follows: In other words, the additive 5bzOasSiO2+ Zr0z * 5nOz mainly reacts with the basic component Zn○ to form ZnvSbzOt2.
ZnzSiO4゜Zn2Zr0t, ZnzSnOi crystal grains are generated, and the electrical resistance of the generated crystal grains is lX1
07Ω to 3X1018Ω, basic composition Zn○-TiO
Crystal grains Z n O+ Zr generated from the z-Mgo system
+zHigher than TiO4. This is also thought to be due to an imbalance in the distribution of crystal grains with different electrical resistances in the obtained resistor.

Therefore, a particularly desirable composition of the resistor of the present invention is 0.05 to 3.9 mol% of 5bzOs based on the above-mentioned basic components;
0.2 to 11.7 mol% of 5iOz.

0.1 to 6.0 mol% ZrO2, 0.1 5T102
~5 mol% is added.

The present invention provides a sintered body made of a composite oxide containing zinc oxide as a main component and an oxide different from the zinc oxide as a subcomponent, the sintered body having a temperature coefficient of resistance at 20 to 500°C of I -3Ω/℃~-IXIO-"07℃
, resistance value at 20°C is 50 to 4000 Ω, opening/closing surge resistance is 400 to 800 J/d, and 3 X 10-3
The voltage nonlinear coefficient at ~80 A/cd is 1.0 to 1.
The oxide resistor is characterized in that:

Furthermore, the present invention has zinc oxide as a main component, magnesium oxide 1 to 20 mol%, and aluminum oxide.

A sintered body containing at least one of gallium oxide, lanthanum oxide, and indium oxide alone or in a total amount of 0.1 to 20 mol%, and a low resistance layer having a resistance value lower than that of zinc oxide is formed between the zinc oxide crystal grains. The oxide resistor is characterized by being formed.

In particular, a sintered body consisting of zinc oxide 70-92%, magnesium oxide 3-15% and aluminum oxide 5-15% in molar ratio, zinc oxide 73-91%, magnesium oxide 3-10% in molar ratio, A sintered body consisting of 5-15% aluminum oxide and 1-2% silicon oxide is preferred.

Granules made of zinc oxide and 200Ω 4×1013
It is a composite sintered body with crystal grains that exhibit an electrical resistance value of Ω, and there is a grain boundary layer between the zinc oxide crystal grains that has a lower electrical resistance than the zinc oxide grains. This sintered body may be plate-shaped, columnar or cylindrical, and electrodes are formed on both end faces of the sintered body. The electrode is formed on the entire surface with some edges remaining, and is coated with AQ by thermal spraying etc.
Metals such as these are formed into a film.

A grain boundary layer having the same electrical resistance value as the zinc oxide crystal grains may exist between each crystal grain. It is desirable that the crystal grains of zinc oxide compounds and oxides other than zinc oxide have a resistance higher than that of zinc oxide in the range of 200Ω to 4Xl□zaΩ. Zinc oxide compounds and oxides other than zinc oxide have the following chemical formulas. That is, the basic components ZnO and MgO,
In order to further improve the linearity of voltage-current characteristics, ZnYz
Number O.

ZnGa20a, ZnLazO++ ZnA Q 20
4. ZnIr+zoa.

MgA Q zoay MgY zo4+MgGaz
oi, MgLazO number.

M'gIr+zO+, Al2203. Y2O5eGa2
0a, Laxon, and InzO8. In order to form these compounds, aluminum (Af) is added to the main components ZnO and MgO.
l).

Yttrium (Y), gallium (Ga), rankan (L)
a) and addition of a metal or metalloid element such as indium (In). The use of bismuth (Bi) is undesirable. This is because when Bi is used, a high resistance layer is likely to be formed in the grain boundary phase.

The basic ingredients of the raw materials for the sintered body are zinc oxide (ZnO) and magnesium oxide (MgO), with ZnO as a subcomponent.
, trivalent metals other than MgO, metalloid oxides aluminum oxide (A n 20 a) + yttrium oxide (Y
2O3), gallium oxide (Ga20δ).

Lanthanum oxide (La20g) and indium oxide (I
n203).

That is, the basic components are zinc oxide and magnesium oxide, and aluminum oxide, yttrium oxide, gallium oxide, lanthanum oxide, indium wt oxide, etc. are added to improve the linearity of the voltage-current characteristics of the resulting oxide resistor. The characteristics of the resistor were investigated. As a result, (1) the switching surge withstand capacity is 800 J/d, approximately four times that of the conventional product, and (2) the temperature coefficient of resistance is significantly higher than that of the basic component, zinc oxide (Zn).
(3) The linearity of the resistance value and voltage-current characteristics is improved by changing the content of magnesium oxide (MgO) from the negative to the positive. xo a).

Yttrium oxide (Y2O3), gallium oxide (Ga
It has been discovered that this can be improved by adding lanthanum oxide (LazOs)-indium oxide (InzOa), etc.

The basic composition of the resistor of the present invention is preferably 70 to 99.5 mol% zinc oxide, 0.2 to 15 mol% magnesium oxide, and AQzOa.

At least one of the oxides of Y2O3, GazOs, LazOs, and InzOa is added in an amount of 0.3 to 15 mol%. The temperature coefficient of resistance of MgO changes greatly from negative to positive by changing the content, and the temperature coefficient of resistance changes from negative to positive at most from the above composition range to at least −I×10−”07°C to +1×
It becomes larger than 10-3Ω/°C.

Moreover, if the MgO content is increased beyond the above composition range, the switching surge withstand capacity becomes less than 400 J/cd, which is not preferable as a resistor for a circuit breaker. In addition, the subcomponent AQ 208
9 Y2O3, GazOs, La20++Inz○8
In the case of , the resistance value will be 400 if it exceeds the above composition range.
0Ω], and the switching surge resistance decreases, making it unsuitable as a circuit breaker resistor. However, AQ
zOst YzOa, GazOatLazOa, Inz
The reason why the addition of Oa allows the resistance value to be controlled and the linearity of the voltage-current characteristics to improve is considered as follows. That is, the subcomponents A Q ios, G a 20
a, I n20a, Lazos (1) mainly reacts with basic components Zn○ and MgO to form ZnAQ2041ZnYz
○4! ZnGaC)4. Zn LazO4+ZnI
n2O+, MgA Q xo4. MgYzo number, MgG
azO4+MgLazO4, MgIr+zO crystal grains are generated, and the electrical resistance of the generated crystal grains is 500Ω to 4×10”Ω, which is higher than the crystal grains ZnO and MgO generated from the basic composition Zn○-MgO system, (2) Generation. AQ, Y, Ga, and La are present in the ZnO crystal grains.

This appears to be caused by diffusion of In and increasing the carrier concentration of ZnO crystal grains.

A particularly desirable composition of the resistor of the present invention is Zn○75-92
．． '7-1=/L/%, MgO0.2 to 15 mol%,
A Q z○81-20 mol%, Y2O30, 3-5 mol%, Ga20a 0.3-10 mol%, InzOa 0.
At least one of LazOso and LazOso is added in an amount of 2 to 5 mol%.

The sintered body is manufactured by, for example, thoroughly mixing the above-mentioned oxide raw material powder, adding water and a suitable binder such as polyvinyl alcohol, granulating the mixture, and molding the mixture using a mold. The molded body is fired in the atmosphere at a temperature of 120θ to 1600°C using an electric furnace. Both end faces of the fired sintered body that form the electrodes are polished! 51! ! L. Form the electrode by plasma spraying or baking method. The obtained resistor may be provided with a high-resistance ceramic layer or a glass layer on the side surface of the resistor in order to prevent creeping discharge during use. The obtained resistor generally exhibits linearity, but if it exhibits nonlinearity, it is effective to apply a high voltage to destroy the high resistance portion (particularly the grain boundary layer).

Example 1 Basic components Zn○3460g (81.7%), TiOz
398g (9,6%), Mg0102g (4,9%)
In contrast, 50 g of S bzoal (1,
0%), 510260g (1,9%).

62 g (0.9%) of Zr0z was accurately weighed and mixed in a ball mill at 15 hours. () is the molar ratio. After the mixed powder is dried, 5% polyvinyl alcohol aqueous solution is mixed in at 5% by weight based on the dry raw powder and granulated. Granulated powder is 35 nm using a mold at a molding pressure of 550 kg/cn.
Shape to φX20mm.

The molded body was fired at 1400° C. for 3 hours in the atmosphere. The temperature raising/lowering rate at this time was 50°C/h.

The crystal grains generated in the obtained sintered body have an electrical resistance of about 2
0Ω Zn○ crystal, approximately 400Ω Z n z T i
O&crystal, andhi lX107~3x101sΩnozn7S
b20 engineering 2 crystal, ZnzSiO4 crystal, Zr+zZrO
+Crystals are being generated.

Separately, ASF-140 manufactured by Asahi Glass Co., Ltd. is a low melting point crystallized glass.
0 glass (ZnO-8i○x-Bx○2 system) powder was suspended in an ethyl cellulose/butyl calpitol solution,
This was applied to the side surface of the fired sintered body with a brush to a thickness of 50 to 300 μm.

This was heat-treated in the atmosphere at 750° C. for 30 minutes to bake the glass. Both end faces of the glass-covered sintered body were polished by approximately 0.51 with a lap master.

Washed with trichlorethylene. The cleaned sintered body is AQ
Electrodes were formed to form a resistor. Table 1 shows a comparison of the switching surge resistance, temperature coefficient of resistance, and rate of change in resistance value after heat treatment at 500° C. in the atmosphere between the product of the present invention and the conventional product.

It can be seen from Table 1 that the products of the present invention have significantly greater switching surge resistance than conventional products, and are superior in terms of resistance temperature coefficient and resistance temperature change rate after heat treatment at 500°C.

Figure 1 is a schematic diagram of the microstructure of the resistor obtained, and Figure 2 shows the specific gravity (g/a() and switching surge resistance (J/cd) of the resistor.
Figure 3 is a diagram showing the relationship between the voltage of the obtained resistor and -
FIG. 3 is a diagram showing current characteristics. The electrical resistance of the produced crystal grains was measured by mirror-polishing the sintered body, analyzing it with a scanning electron microscope, forming a fine electrode on the surface of each crystal grain, and measuring it from the current and voltage.

An example of the resistor structure of the present invention is shown in FIGS. 4 and 5.

4 and 5 are schematic cross-sectional views of an example of the resistor of the present invention. In the figure, 1 means a sintered body, 2 an electrode, and 3 a film of crystallized glass or a ceramic material.

In the present invention, as shown in FIG. 5, a hole may be provided in the center of the resistor.

Example 2 In order to obtain changes in properties depending on the blending ratio of the basic components ZnO, TiO2 and MgO, the blending formula (100% formula % was varied up to 40 mol% and the blended amount was accurately weighed. The weighed raw material powder was As in Example 1, 1300 ~
It was fired by holding it at a temperature of 1600° C. for 4 hours.

The density of each of the obtained sintered bodies was 94 to 96% of the theoretical density. Both end faces of the fired sintered body are coated with a lap master to approx.
．． It was polished by 5 rrn and ultrasonically cleaned with trichlorethylene. The cleaned sintered body was used as a resistor by forming an AQ sprayed electrode. Table 2 shows the resistance value, switching surge resistance, and resistance temperature coefficient of the obtained resistor.

From Table 2, composition numbers 3 to 5 and composition numbers 7 to 13,
That is, 5 to 20 mol% of TiOz is added to the basic component Zn○, and 10 to 75 to 89.8 mol% of ZnO is added.
Contains mol% of TiOz, and further contains MgO of 0.2~
The characteristics of the resistor with 15 mol% added are that the resistance value is 50 to 1
20Ω, opening/closing surge resistance 420-750J/cd
and resistance [1 to number - I X 10-3 ~ + I X
It can be seen that it is excellent as a resistor for a circuit breaker.

On the other hand, Table 2 shows that the opening/closing surge resistance is significantly improved by adding TiOz to the basic component ZnO. However, if TiO2 is contained too much at 40 mol % (sample number 6), the result will be 180 J/cm3, which is lower than the 200 J/cm3 of the conventional product. In addition, the temperature coefficient of resistance changes from negative to positive by increasing the MgO content, and by selecting the optimal amount of MgO added, ±I
It can be seen that the resistance value can be reduced to within 10-07°C. Furthermore, it can be seen that even if the contents of TiO2 and MgO are increased, the resistance value does not show a large change at about 4XIO to 1.2X102Ω・■. Therefore, a particularly desirable basic component composition for a circuit breaker resistor is Zn○.
It is preferable to contain Ti0z in an amount of 5 to 20 mol % and MgO in an amount of 0.2 to IS mol %.

Example 3 Zn064-88.8 mol% of basic components, T i O
x is 4.6 to 10 mol% and MgO is 3.3 to 7 mol%, and Sbz○8゜5iOz t is added as an additive thereto.
One type selected from ZrC)z and Sn○2 was added to 0.
Example 2
A resistor was produced in the same manner as above by holding it in the air at a temperature of 1200 to 1600°C for 4 hours.

Table 3 shows the resistance value, switching surge resistance, and resistance temperature coefficient of the obtained resistor.

Table 3 Color, additives (DSbxOs 0.05-3.
9 mol%, 0.2 to 11.7 mol% of 5iOz, Zr
0.1 to 8.7 mol% O2, 0.1 5nOz
The characteristics of the resistor obtained by changing the concentration to ~5 mol% are composition number 1.
~5,7~10.13~16°19~22 is resistance value 90
~4 x 103 Ω・-, switching surge withstand capacity 400~810J/cJ, temperature coefficient of resistance -IXIO-δ
It can be seen that it is excellent as a resistor for a circuit breaker within Ω/°C to +I x 10-8 Ω/°C.

On the other hand, from Table 3, the resistance value is 5b20a in the additive.

5iOz* It can be seen that the resistance value increases as ZrO2 and Snow increase. However, the resistance value is 7.6 mol% or more in the case of 5bzOa in the additive (sample number 6), 16.5 mol% or more in the case of 5iOz (sample number 11.12), and 8.7 in the case of Zr0z. mole%
Above, in the case of SnO2, 7.4 mol% or more (sample number 2
3.24) If added, the resistance becomes 4XIO8Ω·1 or more, making it unsuitable as a circuit breaker resistor. In addition, the opening/closing surge resistance is determined by the additives 5bzOs, 5iOz, Zr0z, Sn
If the amount of increase in O2 is too large, it will decrease, and 5b
In the case of zO♂, 7.6 mol% or more (sample number 6), 5
16.5 mol% or more in the case of iOz (sample number 12),
8.7 mol% or more in the case of ZrO2 (sample number 18),
7.4 mol% or more in the case of 5noz (sample number 23.2
4) becomes 70 to 190 J/d, which is 200 Jla of the conventional product.
It becomes smaller than d. Furthermore, the temperature coefficient of resistance is 5bzOa with additives.

SiC2, Zr0z, and SnO2 all showed a tendency from positive to negative as the amount added increased, and 5b20
7.6 mol% or more in case of 3 (sample number 6).

16.5 mol% or more in the case of SiO2 (sample number 11
．． 12), 8.7 mol% or more in the case of Zr0z (sample number 17.18), 7.4 mol% or more in the case of Snow (
For sample number 23.24), 1 x 10-aΩ/℃
It can be seen from the above that it is unsuitable as a resistor for a circuit breaker. For these reasons, additives S b to the basic component Zn0-TlC)z -MgO system as a resistor for circuit breakers
The amount of addition of zoa+s i 021Zr○z and Sn○2 is 0.05 to 3.9 mol% for 5bzOa and 0.05 to 3.9 mol% for 5iOz.
Preferably, the content is 2 to 11.7 mol%, ZrO2 is 0.1 to 6.0 mol%, and Sn○2 is 0.1 to 5.0 mol%.

Example 4 Basic components Zn03420g (82.2 mol%), Mg
AQ as a subcomponent to 101g (4.9 mol%) of O
z○a510g (9.8 mol%), Ga20s47
g (0.5 mol%) and I nxos 369 g (2
, 6 mol %) was weighed accurately and wet mixed in a ball mill for 15 hours. After drying the mixed powder, 5% polyvinyl
An alcohol aqueous solution is added in an amount of 5% by weight based on the dry raw material powder for granulation. The granulated powder is molded using a mold at a pressure of 450 kg/a.
Mold to 35mmφX20a++ using J. The molded body was fired at 1350° C. for 3 hours in the atmosphere. The temperature raising/lowering rate at this time was 70°C/h. The electrical resistance of the crystal grains generated in the obtained sintered body is approximately 10 to 50 Ω.
nO crystal, ZnAl2zO4 crystal of about 70-100Ω,
Mg○ crystal of about 400Ω, ZnGa20tt of about 700 to 4×1018Ω, ZnLaz○t, ZnYzOi+Z
nInzOs, MgA R2041Mg2O41, Mg
Ga204.

MgLazO4+MgInzos+A Q2031G
a203°La20δ, InzO8.Similar to Example 1, an AQtl pole was similarly formed by melting on a sintered body coated with low melting point crystallized glass. Opening/closing surge resistance and temperature coefficient of resistance between this invention and the conventional product (carbon-dispersed ceramic resistor).

Table 4 shows a comparison of the resistance value change rate and the nonlinear coefficient α of the voltage-current characteristics after heat treatment at 500° C. in the atmosphere.

It can be seen that the product of the present invention has an extremely large switching surge resistance and a small voltage nonlinear coefficient α compared to the conventional product. The resistance temperature coefficient of the present invention is positive, and α in the VI characteristic is 1.02.

The measurement of the electrical resistance of crystal grains is the same as described above.

An example of a schematic diagram of the microstructure of the oxide resistor of the present invention is shown in FIG. The reason why a film of crystallized glass or ceramic material is provided on the side surface of the sintered body is to prevent creeping discharge during use.

Example 5 The basic component Zn○ was changed to 65 to 99.95 mol%, MgO was changed to 0.05 to 20 mol%, and AQ was used as a subcomponent.
z○3. Y2O31Laz○sr I nzoa.

One type selected from Ga2es was varied from 0.1 to 30 mol%, and the blending amount was accurately weighed.

The weighed raw material powder had a concentration of 1300 to 1 in the air as in Example 1.
It was fired by holding it at a temperature of 600° C. for 3 hours. The density of each of the obtained sintered bodies was 95 to 98% of the theoretical density. Both ends of the fired sintered body are wrapped with a lap master of approximately 0.5 mm.
It was polished and cleaned ultrasonically with trichlorethylene. The cleaned sintered body was used as a resistor by forming an A0 sprayed electrode.

Resistance value of the obtained resistor.

Table 5 shows the switching surge withstand capacity, resistance temperature coefficient, and voltage nonlinear coefficient α.

From Table 5 7 composition numbers 10-122 composition numbers 16-18
．． Composition number 21-231 Composition number 27-302 Composition number 32-36, i.e. basic component 80-92.9 mol%
ZnO contains 5 to 15 mol% of MgO, and further contains 5 to 15 mol% of A Q z○3 and Y2 as subcomponents.
Add one or more components selected from 0.5 to 5 mol% of O3, 0.3 to 1 mol% of Laz's, 0.5 to 5 mol% of Gazes, and 0.1 to 5 mol% of InzOa. The characteristics of the resistor are resistivity of 110 to 3500Ω, switching surge resistance of 400 to 780J/cJ, and temperature coefficient of resistance of 15.
×10-'Ω/℃ or less, +4.3 Xl0-'Ω/℃
and the voltage nonlinear coefficient α is 1.02 to 1.3,
It can be seen that it is excellent as a resistor for circuit breakers.

Further, from Table 5, it can be seen that the opening/closing surge resistance is improved by adding MgO to the basic component ZnO. Also, by changing the MgO content, the temperature coefficient of resistance changes from negative to positive, and if the amount of MgO added is selected, -I
It can be seen that the resistance can be reduced to 0-8 Ω/°C or less, and +l×10-8 Ω/°C or less.

Further, even if the content of the basic component MgO is increased, the resistance value does not show a large change at about 20 to 500 ΩG, but the resistance value does not show a large change even if the content of the basic component MgO is increased.

91-5x depending on the amount of Gazes and InzOg added
It can be seen that 107ΩG changes significantly. Furthermore, the voltage nonlinear coefficient is the subcomponent A Q 205tYz○s, L
By selecting the optimal addition amount of azos, Gazes, InzOs, etc., it can be significantly improved to 1.02 to 1.3. However, the subcomponent A Q 2031YzOs*
It can be seen that if the amount of La2O3, Ga20a+Inx○3 added is increased too much, the opening/closing surge resistance decreases.

For these reasons, a particularly desirable composition for a resistor for a circuit breaker is a mixture in which the basic component is ZnO and 5 to 15 mol% of MgO, and 5 to 1% of AQz○8 is added as a subcomponent.
5 mol%, Y2O3 0.5-5 mol%, Lazos 0.3-1 mol%, Gazes 0.5-5 mol%, I
It is preferable to add 0.1 to 5 mol% of nzOa.

Example 5 Figures 7 and 8 show the oxide resistors of the present invention obtained in Example 1 and Example 4, respectively, for gas circuit breakers (GCB) closing resistance and SFs gas insulated neutral point grounding (NCR). ) shows an example of its application. The resistor 5 used in FIGS. 7 and 8 has a cylindrical shape as shown in FIG. 5.

In the figure, 6 closing resistors, 7 resistor support rods, 8 capacitors,
9 circuit breaker, 10 oil doss pot, 11 opening/closing operation piston, 12 air tank, 13 bushing, 14 tank,
15 is the ground terminal.

〔Effect of the invention〕

According to the present invention, as described above, the switching surge resistance is extremely high, the voltage non-linearity coefficient of the voltage-current characteristic is small, the resistance temperature coefficient is positive and small, and the resistance temperature change after heat treatment at 500°C is also small. Since the oxide resistor is used, the device is smaller and lighter.

[Brief explanation of drawings]

1 and 6 are schematic diagrams showing the microstructure of an oxide resistor according to an example of the present invention, and FIG. 2 is a characteristic diagram showing the relationship between the specific gravity of the oxide resistor and the switching surge withstand capacity of the circuit breaker. , FIG. 3 is a diagram showing the relationship between electric field strength and current density, FIGS. 4 and 5 are cross-sectional views of an oxide resistor according to an embodiment of the present invention,
FIG. 7 is a configuration diagram of a GCB closing resistor, and FIG. 8 is a configuration diagram of an SFa gas insulated neutral point grounding (NGR).

Claims (1)

[Scope of Claims] 1. A composite oxide sintered body composed of crystal grains made of zinc oxide and crystal grains made of a zinc oxide compound of a metal or metalloid element other than zinc, wherein each of the crystals An oxide resistor characterized by the presence of a grain boundary layer between the grains, the electrical resistance of which is equal to or lower than that of zinc oxide crystal grains. 2. The oxide resistor according to claim 1, wherein a grain boundary layer having the same electrical resistance as the zinc oxide crystal grains exists between each of the crystal grains. 3. The oxide resistor according to claim 1, wherein there is a gap between each of the crystal grains at a portion corresponding to a grain boundary. 4. The oxide resistor according to claim 1, wherein the metal or metalloid element is selected from titanium, silicon, antimony, zirconium, and tin. 5. An oxide resistor according to claim 1, wherein the zinc oxide compound is selected from those represented by the following chemical formula: Zn_2TiO_4, Zn_2SiO_4, Zn_7
Sb_2O_1_2, Zn_2ZrO_4, Zn_2S
nO_4. 6. In claim 1, the electrical resistance of the crystal grains of the zinc oxide compound is from 200Ω to 3×10^1.
An oxide resistor characterized by having a resistance in the range of ＾3Ω, which is higher than that of zinc oxide crystal grains. 7. Crystal grains made of zinc oxide and 3×10 from 200Ω
It is a composite sintered body with crystal grains that exhibit an electrical resistance value of ^1^3Ω, and there is no grain boundary layer with higher electrical resistance than zinc oxide crystal grains, and the sintered body is plate-shaped and has electrodes on both end faces. An oxide resistor characterized by forming. 8. A sintered body made of a composite oxide containing zinc oxide as a main component and an oxide different from the zinc oxide as a subcomponent, the sintered body having a temperature coefficient of resistance of 1 x 10^- at 20 to 500°C. ＾3Ω/℃〜-1×10＾−＾3Ω/℃,
Resistance value at 20℃ is 40-4000Ωcm, switching surge resistance is 400-800J/cm^3 and 3x10^
- Voltage nonlinear coefficient between 3 and 80 Å/cm^3 is 1
．． An oxide resistor characterized in that the resistance is 0 to 1.3. 9. Zinc oxide as main component, magnesium oxide 0.2~
15 mol% and at least one of aluminum oxide, yttrium oxide, gallium oxide, lanthanum oxide, and indium oxide alone or in a total amount of 0.1 to 20 mol%, and oxidized between zinc oxide crystal grains. An oxide resistor characterized by forming a low resistance layer having a resistance value lower than that of zinc. 10. The oxide resistor according to claim 9, which is a sintered body consisting of 7 to 92% zinc oxide, 3 to 10% magnesium oxide, and 5 to 15% aluminum oxide in molar ratio. 11. Claim 9, which is a sintered body consisting of 73 to 91% zinc oxide, 3 to 10% magnesium oxide, 5 to 15% aluminum oxide, and 1 to 2% silicon oxide in molar ratio.
The oxide resistor described in section. 12. In a gas circuit breaker (GCB) equipped with an oxide resistor, the oxide resistor has a columnar or cylindrical shape,
It consists of an oxide resistor according to any one of claims 1 to 11, in which an electrode is formed on the end face excluding the outer circumferential face. 13. The gas breaker according to claim 12, wherein insulating glass is baked onto the entire outer peripheral surface of the oxide resistor. 14. SF_6 gas-insulated medium contact with oxide resistor (
12. The oxide resistor according to any one of claims 1 to 11, wherein the oxide resistor has a columnar or cylindrical shape, and an electrode is formed on an end surface other than an outer peripheral surface of the oxide resistor. 15. The NGR according to claim 14, wherein the electrode is formed inside the outer peripheral surface.