JP2003109806A - Nonlinear resistor and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonlilnear resistor the thickness of which can be increased and the discharge withstand current rating characteristic of which can be improved. SOLUTION: The nonlinear resistor, the main component of which is zinc oxide (ZnO), contains bismuth, titanium, cobalt, manganese, and nickel as sub- components, the contents of which are set to 0.1-5.0 mol% in terms of bismuth oxide (Bi2 O3 ), 0.1-5.0 mol% in terms of titanium oxide (TiO2 ), 0.1-5.0 mol% in terms of cobalt oxide (CoO), 0.1-5.0 mol% in terms of manganese oxide (MnO), and 0.1-5.0 mol% in terms of nickel oxide (NiO), respectively, and further contains tellurium, the content of which is set to 0.001-3.0 mol% in terms of tellurium oxide (TeO2 ).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-linear resistor containing zinc oxide as a main component used in lightning arresters, surge absorbers and the like, and a method for manufacturing the same.

[0002]

2. Description of the Related Art In a power system or an electronic device circuit, a lightning arrester or a surge absorber is generally used for the purpose of suppressing the intrusion of abnormal voltage and protecting the power system and the electronic device. The surge arresters and surge absorbers employ a non-linear resistor that protects the system and circuit by exhibiting insulation characteristics at normal voltage and low resistance characteristics when an abnormal voltage is applied. .

Conventionally, the manufacturing method of this non-linear resistor is roughly as follows.

The raw material contains ZnO as a main component, and as a sub-component, for example, Bi ₂ O ₃ , SB ₂ O ₃ , CoO, MnO, and Cr as disclosed in JP-A-5-234716.
₂ O ₃ etc. are added. After thoroughly mixing these raw materials with water and an organic binder, they are granulated with a spray dryer or the like, molded and sintered. After that, a high resistance material is applied to the side surface of the sintered body to prevent creeping flashover and refired to form a high resistance layer. Then, both end surfaces of the sintered body are polished and electrodes are attached to manufacture a non-linear resistor.

By the way, in recent years, the capacity of electric power systems has been increased in order to reduce the transmission cost. The non-linear resistors used in these lightning arresters are required to handle extremely large surge energy, and thus the non-linear resistors have been adopted with a large capacity and an increased number of parallel connections.

However, the increase in the number of parallel connections is limited due to problems in characteristics such as imbalance in current sharing, and inevitably the capacity of the non-linear resistor must be increased. Therefore, increasing the element diameter is limited by the diameter of the cylindrical container that houses it.

On the other hand, the thickness of the non-linear resistor is limited by the balance between the rising voltage of the non-linear resistor (hereinafter referred to as varistor voltage) and the limiting voltage of the lightning arrester. The current varistor voltage of the non-linear resistor is 180 to 300 V / mm, but if the varistor voltage can be lowered, the thickness of the non-linear resistor can be increased, and the amount of energy processing can be increased. Can be planned. Therefore, a nonlinear resistor having a low varistor voltage has been desired.

The shape of the non-linear resistor obtained by the current manufacturing method is 100 to 120 mm in diameter and 20 to 45 in thickness.
It also becomes mm. Such a large non-linear resistor causes another problem. That is, in a sintered body used for a large non-linear resistor, ZnO crystal grains undergo abnormal grain growth due to the influence of partial non-uniform firing temperature at the time of sintering, resulting in variation in resistance value. It will be easier. Further, there is a problem that current concentrates on a portion having low resistance, resulting in deterioration of withstand voltage characteristics and deterioration of life characteristics.

[0009]

As described above, the conventional non-linear resistor has a high varistor voltage, and it is difficult to increase the thickness of the non-linear resistor due to the restriction by the voltage limit of the lightning arrester. Further, when the size is increased, there is a problem that a partial variation in the resistance value occurs in the sintered body, and the discharge withstand voltage characteristic and the electric charge life characteristic are deteriorated.

The present invention has been made to solve the above-mentioned problems, and even if the size is increased, there is little variation in the resistance value.
It is an object of the present invention to provide a non-linear resistor having excellent discharge withstand characteristics and voltage application life characteristics and a method for manufacturing the same.

[0011]

In order to achieve the above object, the present invention constitutes a non-linear resistor by the following means and manufactures this non-linear resistor by the following method. Is.

The invention corresponding to claim 1 is zinc oxide (Z
nO) as a main component, and bismuth, titanium, cobalt, manganese, and nickel as auxiliary components are each converted into bismuth oxide (Bi ₂ O ₃ ) of 0.1 to 5.0 mol.
%, Converted to titanium oxide (TiO ₂ ) 0.1 to 5.0
mol%, 0.1 to 0.1% converted to cobalt oxide (CoO)
5.0 mol%, 0.1-5.0 mol% in terms of manganese oxide (MnO), 0.1-5.0 mol% in terms of nickel oxide (NiO), and tellurium (TeO) oxide. ₂ ) converted to 0.001 to 3.0
Contains mol%.

According to the non-linear resistor of the invention corresponding to claim 1, since the main component is zinc oxide and the auxiliary components include bismuth, titanium, cobalt, manganese, and tellurium, the ZnO crystal grain size is made uniform. Can be bigger,
The surge resistance can be increased.

The invention corresponding to claim 2 corresponds to claim 1.
In the non-linear resistor of the present invention, rubidium oxide
(Rb₂0.5 x 10 when converted to O)^-3~ 20 x 10^-3
mol% rubidium, silver oxide (Ag₂Converted to O)
0.5 x 10^-3~ 20 x 10^-3mol% silver, Tari oxide
Umm (Tl₂0.5 x 10 when converted to O)^-3~ 20 x 1
0^-3mol% thallium, cesium oxide (Cs₂O)
Converted to 0.5 x 10^-3~ 20 x 10^-3mol% sesame
Um, boron oxide (B₂O₃) Converted to 5 x 10 ^-3~ 2
0x10^-3At least one component of mol% boron
contains.

According to the non-linear resistor of the invention according to the second aspect, excellent life characteristics can be obtained.

The invention corresponding to claim 3 is the nonlinear resistor of the invention according to claim 1 or claim 2, wherein aluminum is converted into aluminum oxide (Al ₂ O ₃ ) and 0.5 × 10 ^{−. 3 to} 20 × 10 ⁻³ mol% is contained.

According to the non-linear resistor of the invention according to the third aspect, by containing aluminum, excellent non-linear characteristics can be obtained.

In the invention corresponding to claim 4, zinc oxide is a main component, and bismuth oxide (B
i ₂ O ₃ ) 0.1 to 5.0 mol%, titanium oxide (TiO ₂ ) 0.1 to 3.0 mol%, cobalt oxide (CoO) 0.1 to 5.0 mol
%, Converted to manganese oxide (MnO) of 0.1 to 5.0
mol%, 0.1 to 0.1% converted to nickel oxide (NiO)
5.0 mol% is included, and titanium telluride (TiT
e ₂₎ a containing 0.001~3.0mol%.

In the invention corresponding to claim 5, bismuth oxide (B) is composed mainly of zinc oxide and bismuth, titanium, cobalt, manganese and nickel as auxiliary components.
i ₂ O ₃ ) 0.1 to 3.0 mol%, titanium oxide (TiO ₂ ) 0.1 to 5.0 mol%, cobalt oxide (CoO) 0.1 to 0.1 mol%. 5.0 mol
%, Converted to manganese oxide (MnO) of 0.1 to 5.0
mol%, 0.1 to 0.1% converted to nickel oxide (NiO)
5.0 mol% of bismuth telluride (Bi
₂ Te ₃ ) and 0.001 to 3.0 mol% is contained.

According to the non-linear resistor of the inventions corresponding to the above claims 4 and 5, the particles containing titanium telluride (TiTe ₂ ) and bismuth telluride (Bi ₂ Te ₃ ) are contained as the additives. Te can be easily solid-dissolved in the interface, and excellent current-voltage characteristics can be obtained.

The invention corresponding to claim 6 is the nonlinear resistor according to any one of claims 1, 4, and 5, wherein the bismuth crystal phase contained is from α phase or β phase. And the relative intensity ratio α / β is 0.5 or more.

According to the non-linear resistor of the invention corresponding to the above-mentioned claim 6, since the crystalline phase becomes stable against thermal stress, excellent life characteristics can be obtained.

The invention according to claim 7 is the linear resistor according to any one of claims 1 to 5, wherein the element has a porosity of 10% or less.

According to the non-linear resistor of the invention corresponding to claim 7, the strength of the element can be improved by setting the porosity of the element to 10% or less, and excellent discharge withstand characteristics can be obtained. be able to.

According to an eighth aspect of the present invention, zinc oxide as a main component and bismuth as a sub-component which is weighed in a predetermined amount are included.
Titanium, cobalt, manganese, nickel and tellurium are used as raw materials, and the raw materials are mixed with an organic binder by a mixing device, and the mixture is made into granulated powder having a predetermined particle size by a granulating means, and the granulated powder is used as a mold. And pressurize it into a molded product of a predetermined shape. Then, this molded product is fired at a predetermined temperature to obtain a sintered body, and after coating the side surfaces of this sintered body, conductive materials are applied to both end surfaces. Is sprayed to form electrodes.

The invention corresponding to claim 9 is such that zinc oxide as a main component and bismuth as an auxiliary component which is weighed in a predetermined amount,
Titanium, cobalt, manganese, nickel, tellurium as a raw material, further rubidium weighed as an addition amount,
Using silver, thallium, and cesium as raw materials, these raw materials are mixed with an organic binder in a mixing device, and the mixture is made into granulated powder having a predetermined particle size by a granulating means, and the granulated powder is put into a mold and added. Press to form a molded body of a predetermined shape, and then calcine this molded body at a predetermined temperature to obtain a sintered body,
After coating the side surfaces of this sintered body, a conductive material is sprayed on both end surfaces to form electrodes.

According to the method for manufacturing a non-linear resistor of the present invention corresponding to claims 8 and 9, there is little variation in the resistance value even when the size is increased, and the non-linear resistance is excellent in discharge withstand characteristics and electric charge life characteristics. The body can be manufactured.

The invention according to claim 10 is the method for producing a non-linear resistor according to claim 9, wherein the rubidium, silver, thallium and cesium components are added in the form of a salt solution.

An invention corresponding to claim 11 is claim 10
In the method for manufacturing a non-linear resistor according to the invention, the solution of rubidium salt, silver salt, thallium salt, and cesium salt is a solution of nitrate salt.

According to the method for manufacturing a non-linear resistor of the present invention corresponding to claims 10 and 11, silver, thallium and cesium components can be uniformly dispersed, and excellent life characteristics without variations can be obtained. .

The invention corresponding to claim 12 is the method for producing a non-linear resistor according to claim 8 or 9, wherein the firing temperature of the molded body is 1050 to 1250.
℃, from 1000 ℃ to 750 ℃ temperature decrease rate is 50-2
00 ° C / h, varistor voltage Varistor voltage is 15 ~
It is 120 V / mm.

According to the method of manufacturing a non-linear resistor of the invention corresponding to claim 12, it is possible to extremely reduce variations in resistance value.

According to a thirteenth aspect of the present invention, in the method for manufacturing a non-linear resistor according to the ninth or ninth aspect of the invention, brass is sprayed on opposite end faces of the non-linear resistor, and the terminal fitting is made of a low melting point metal. To join.

According to the non-linear resistor manufacturing method of the invention corresponding to claim 13, the electrode and the element body can be integrated,
The number of parts can be reduced and the reliability can be improved.

The invention corresponding to claim 14 is claim 13
In the method for manufacturing a non-linear resistor according to the invention, the low melting point metal is Sn, Ag, and Zn, Cu, Ti.
From 70 to 99.8% Sn,
Ag, 0.2-10%, Zn0-10%, Cu0-1
0% and Ti 0 to 10%.

According to the method for producing a nonlinear resistor of the invention corresponding to claim 14, a low melting point metal having few pores can be obtained, and excellent bonding strength can be obtained.

According to a fifteenth aspect of the invention, in the method for manufacturing a non-linear resistor according to the eighth or ninth aspect of the invention, terminal metal fittings are joined to the opposite end faces with a conductive resin material.

According to the method for manufacturing a non-linear resistor of the invention corresponding to claim 15, baking can be performed at a low temperature, and stable life characteristics can be obtained.

[0039]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

The first embodiment of the present invention will be described.

Bismuth oxide (Bi ₂ O ₃ ), titanium oxide (TiO ₂ ), cobalt oxide (CoO), manganese oxide (MnO), nickel oxide (NiO) and tellurium are added to tellurium oxide as the main component zinc oxide (ZnO). A predetermined amount of (TeO ₂ ) is weighed and used as a raw material. In this case, Bi ₂ O ₃ is 0.1 to 5.0 mol% and TiO ₂ is 0.1 to 5.0 m.
ol%, CoO 0.1-5.0 mol%, MnO 0.1-5.0 mol%, NiO 0.1-5.0 mo
1%, and TeO ₂ is in the range of 0.001 to 3.0 mol%.

These raw materials are mixed with water and an organic binder such as a dispersant in a mixing device.

Next, the mixture is spray-granulated to have a predetermined particle size of 100 μm, for example, by a spray dryer. Then, the granulated powder is put into a mold and pressurized, and is molded into a predetermined shape such as a disk to obtain a molded body. The molded product thus obtained is fired in air at, for example, 500 ° C. in order to remove the added organic binders, and further 1200 ° C. in air.
By firing at 2 ° C. for 2 hours, a sintered body 1 as shown in FIG. 1 can be obtained. Then, the side surface portion is coated with low melting point glass to obtain the side surface layer 2. Further sintered body 1
Both end surfaces are polished, and aluminum is sprayed on the both end surfaces to form the electrodes 3. With this, the nonlinear resistor shown in FIG. 1 can be obtained.

The electrical characteristics of the non-linear resistor obtained as described above will be described.

Table 1 shows the varistor voltage, discharge withstand voltage characteristic, nonlinear characteristic, and porosity of these nonlinear resistors.

[0046]

[Table 1]

In Table 1 above, the discharge withstand voltage characteristic is 18
The lightning impulse was applied to each of the non-linear resistors while sequentially increasing the current value, and the average value of the current values withstood by the non-linear resistors was shown.

The thickness of the non-linear resistor is adjusted,
A discharge withstand voltage test was conducted with the same varistor voltage of one non-linear resistor. The nonlinear characteristic is the ratio of the voltage V _5kA generated when a current of _5kA is applied to the varistor voltage V _5kA / V
_Shown at _{1 mA} .

Table 2 shows the varistor voltage, discharge withstand voltage characteristic, non-linear characteristic, and porosity of the conventional example for comparison with the present embodiment.

[0050]

[Table 2]

As is clear from the comparison between Table 1 and Table 2, the non-linear resistor of the present embodiment has a varistor voltage of 15 to 120 V / mm as compared with the conventional example and has a good discharge withstand characteristic. I know that there is. Further, it can be seen that when the porosity exceeds 10%, the discharge withstanding characteristic is deteriorated.

As described above, in the embodiment of the present invention,
The reason why a non-linear resistor having a better discharge withstand characteristic than the conventional example can be obtained is considered as follows.

The resistance of the non-linear resistor containing ZnO as a main component appears at the grain boundaries of ZnO particles. Therefore,
The resistance of a nonlinear resistor is the reciprocal of the number of grain boundaries, that is, Zn
It is determined by the particle size of O particles.

The growth of ZnO particles is influenced by the added subcomponents. That is, Bi ₂ O ₃ becomes a liquid phase during sintering, dissolves ZnO, and promotes the movement thereof, thereby promoting the growth of ZnO crystal particles.

On the other hand, TiO ₂ promotes the growth of ZnO crystal grains by increasing the solubility of ZnO.
TeO ₂ has a low melting point and becomes a liquid phase like Bi ₂ O _3, but Z
Since the solubility of nO is low, it does not promote the growth of ZnO crystal grains as much as Bi ₂ O ₃ .

If only the growth of ZnO crystal grains is promoted, excessive grain growth, abnormal grain growth, or variation in grain size may occur. Here, when tellurium is added, the balance of grain growth of ZnO is improved, and as a result, variations can be reduced, the varistor voltage of the non-linear resistor can be lowered, and the porosity of the element body can be reduced. It is considered that by reducing the amount, the mechanical strength of the element body is improved, and a non-linear resistor having excellent discharge withstand capability can be obtained.

In the present embodiment, the antimony (S) contained in the conventional example (for example, Japanese Patent Laid-Open No. 5-234716) is used.
b), which does not contain chromium (Cr), these react with ZnO during firing to form a composite oxide. These complex oxides inhibit the growth of ZnO crystal grains,
The varistor voltage cannot be lowered.

In the present embodiment, since these two components are not contained, it is confirmed that excellent ZnO crystal particles can be obtained, a varistor voltage is low, and a non-linear resistor having good withstand voltage characteristics is obtained. is doing.

The bismuth auxiliary component is converted to Bi ₂ O ₃ in an amount of 0.1 to 5.0 mol%, titanium is converted to TiO ₂ in an amount of 0.1 to 5.0 mol%, and cobalt is converted to CoO. 0.1 to 5.0 mol%, manganese converted to MnO 0.1 to 5.0 mol%, nickel converted to NiO 0.1 to 5.0 mol%, and tellurium TeO ₂ The reason why the content of 0.001 to 3.0 mol% is calculated is that if the content is out of these ranges, the resistance of the varistor voltage is increased, the discharge withstand capability is lowered, and the non-linear characteristic is deteriorated.

Next, a second embodiment of the present invention will be described.

Bi ₂ O ₃ , TiO ₂ and C are contained in the main component ZnO.
1 mol% each of oO, MnCo ₃ , and NiO, Te
O ₂ was weighed in an amount of ₂ mol%, and rubidium, silver, thallium, cesium, and boron were added to Rb ₂ O, Ag ₂ O, and
A predetermined amount of Tl ₂ O, Cs ₂ O, and B ₂ O ₃ was weighed, and using these as raw materials, a non-linear resistor was manufactured by the same manufacturing method as in the first embodiment.

The non-linear resistor of the present embodiment has a varistor voltage of 15 to 120 V / mm as in the first embodiment, and has a good discharge withstand characteristic.

The non-linear resistor obtained as described above was applied with a voltage of 90% of the varistor voltage in a thermostatic chamber at 120 ° C., and a voltage application life test was conducted for 1000 hours. The results are shown in Table 3.
Shown in.

[0064]

[Table 3]

The life characteristics are shown by L1000.

L1000 = [V (after 1000 h) + V (initial)] / [V
(Initial)] × 100 As is apparent from the results shown in Table 3 above, it can be seen that the non-linear characteristics are improved in life characteristics by adding rubidium, silver, thallium, cesium and boron. By the way, No. * 16 indicates the case where neither of the above components is added.

The reason why the life characteristics are improved in the second embodiment of the present invention is considered as follows.

The interface level formed at the ZnO varistor grain boundary is an acceptor type, and an electron is trapped therein, and an electric barrier is formed by the positively ionized donor to compensate the trapped electron.

For example, the added rubidium becomes Rb ⁺ , enters between ZnO crystal lattices, and the state of the interface state is changed, and even if the electric field stress occurs, the interface state resistant to the change is formed and the life characteristics are improved. It is considered to have been improved.

The amount of Rb ₂ O added was 0.5 × 10 5.
^If it is less than ^-3 mol%, the amount of addition is small and the effect of improving the nonlinear characteristics is small. Further, when it exceeds 20.0 × 10 ⁻³ mol%, it is considered that the amount of Rb ⁺ increases, the resistance at the grain boundary decreases, and the nonlinear characteristics deteriorate.

Although rubidium has been described here, it is considered that silver, thallium, cesium and boron also have improved life characteristics by the same mechanism.

In the present embodiment, Bi ₂ O ₃ , TiO ₂ ,
CoO, MnCo ₃ , and NiO are 1 mol% and T, respectively.
Although eO ₂ shows a case containing containing 2 mol%, Bi ₂
0.1 to 5.0 mol% in terms of O ₃ , 0.1 to 5.0 mol% in terms of TiO ₂ , 0.1 in terms of CoO
~ 5.0mol%, 0.1-5.0m in terms of MnO
0.1 to 5.0 mol% in terms of ol% and NiO, and 0.001 to 3.0 mo in terms of TeO _2.
It was confirmed that the same effect was obtained even when the content was 1%.

Next, a third embodiment of the present invention will be described.

Bi ₂ O ₃ , TiO ₂ and C are used as main components ZnO.
1 mol% each of oO, MnCo ₃ , and NiO, and 2 mol% of TeO ₂ were weighed.
A predetermined amount of 1 ₂ O ₃ was weighed and used as a raw material, and a non-linear resistor was manufactured by the same manufacturing method as in the first embodiment.

The non-linear resistor of this embodiment has a varistor voltage of 15 to 120 V / mm, as in the first embodiment.
The discharge withstand characteristic is also good.

The non-linearity of the non-linear resistor obtained as described above is shown as plot A in FIG.

In addition, the main component ZnO contains Bi ₂ O ₃ and TiO _2.
2 , CoO, MnCo ₃ , and NiO are each 1 mol%,
₂ mol% TeO ₂ and 1 × rubidium in the form of Rb ₂ O
10 ^{- 3} mol% weighed, further an aluminum Al ₂ O ₃
A predetermined amount was weighed in the form of, and these were used as raw materials to manufacture a non-linear resistor by the same method as in the first embodiment.

The non-linear resistor of this embodiment has a varistor voltage of 15 to 120 V / mm, as in the first embodiment.
The discharge withstand characteristic is also good.

The non-linearity of the non-linear resistor obtained as described above is shown as a plot B in FIG.

As is clear from the results shown in FIG. 2, the non-linear characteristic is further improved as compared with the first embodiment.

The reason why the non-linear characteristic is improved in the third embodiment of the present invention is considered as follows.

The added aluminum becomes Al ³⁺ and forms a solid solution in the ZnO crystal particles. Al ³⁺ is ZnO
It exists near the grain boundaries of the particles and forms a barrier that causes the development of nonlinear characteristics. Therefore, it is considered that the addition of aluminum improved the nonlinear characteristics.

In the present embodiment, ZnO is mixed with Bi ₂ O ₃ ,
TiO ₂ , CoO, MnCo ₃ , and NiO are each 1mo
1% and ₂ mol% of TeO ₂ are included, but it is 0.1 to 5.0 mol% in terms of Bi ₂ O ₃ and T
0.1 to 5.0 mol% in terms of iO ₂ , 0.1 to 5.0 mol% in terms of CoO, and 0.1 in terms of MnO.
1-5.0 mol%, converted to NiO 0.1-5.0
mol% content, 0.000 in terms of TeO ₂
In the case of containing 1 to 3.0 mol% and further converting rubidium into rubidium oxide (Rb ₂ O), 0.5 × 1
^{0 -3 ~20 × 10 - 3 mol} %, silver silver oxide (Ag ₂ O)
0.5 × 10 ^{−3 to} 20 × 10 ⁻³ mol%, and thallium oxide (Tl ₂ O) is converted to 0.5 ×
10 ^{−3 to} 20 × 10 ⁻³ mol%, 0.5 × 10 ^{−3 to} 20 × 10 in terms of cesium converted to cesium oxide (Cs ₂ O)
^-3 mol%, it was confirmed that a similar effect with the case of containing ^{5 × 10 -3 ~20 × 10 -3} mol% in terms of boron boron oxide (B ₂ O ₃₎ is obtained.

Next, a fourth embodiment of the present invention will be described.

Bi ₂ O ₃ , TiO ₂ and C were added to the main component ZnO.
1 mol% each of oO, MnCo ₃ , and NiO, and 2 mol% of TeO ₂ were weighed, and rubidium,
RbOH and AgO for silver, thallium and cesium, respectively
A predetermined amount of H, T1OH, and CsOH was weighed and used as a raw material, and a non-linear resistor was manufactured by the same manufacturing method as in the first embodiment.

The non-linear resistor of this embodiment has a varistor voltage of 15 to 120 V / mm, as in the first embodiment.
The discharge withstand characteristic is also good.

Table 4 shows the non-linearity of the non-linear resistor obtained as described above.

[0088]

[Table 4]

Further, the main component ZnO contains Bi ₂ O ₃ and TiO _2.
2 , 1 mol of CoO, MnCo ₃ and NiO
%, And ₂ mol% TeO ₂ were weighed, and rubidium, silver, thallium, and cesium were added to RbNO ₃ , and
A predetermined amount of AgNO ₃ , TlNO ₃ , and CSNO ₃ was weighed and used as raw materials, and a non-linear resistor was manufactured by the same manufacturing method as in the first embodiment.

The non-linear resistor of this embodiment has a varistor voltage of 15 to 120 V / mm, as in the first embodiment.
The discharge withstand characteristic is also good. Table 5 shows the non-linearity of the non-linear resistor obtained as described above.

[0091]

[Table 5]

As is clear from the results shown in Tables 4 and 5, the non-linear characteristic is further improved as compared with the second embodiment.

The reason why the non-linear characteristic is improved in the fourth embodiment of the present invention is considered as follows. It is considered that by adding the added rubidium, silver, thallium, and cesium in the form of a salt solution, they can be uniformly dispersed and excellent life characteristics without variations can be obtained.

In the present embodiment, Bi ₂ O ₃ , TiO ₂ ,
The case where CoO, MnCo ₃ , and NiO are each contained at 1 mol% and TeO ₂ is contained at 2 mol% is shown.
0.1 to 5.0 mol% in terms of i ₂ O _3, 0.1~5.0mol% in terms of TiO _2, 0.1 to 5.0 mol% in terms of CoO, terms of MnO 0.1 to
5.0 mol%, 0.1 to 5.0 mo converted to NiO
1% content, and 0.001 converted to TiO ₂
It was confirmed that the same effect was obtained when the content was 3.0 mol%.

Next explained is the fifth embodiment of the invention.

Bi ₂ O ₃ , TiO ₂ and C are used as main components ZnO.
1 mol% of each of oO, MnCo ₃ , and NiO, and a predetermined amount of TiTe ₂ were weighed out and used as raw materials.
A non-linear resistor was manufactured by the same manufacturing method as in the above embodiment.

The non-linear resistor of this embodiment has a varistor voltage of 15 to 120 V / mm, as in the first embodiment.
The discharge withstand characteristic is also good.

FIG. 3 shows the non-linearity of the non-linear resistor obtained as described above.

In addition, the main component ZnO contains Bi ₂ O ₃ and TiO _2.
2 , CoO, MnCo ₃ , and NiO are each 1 mol%,
Furthermore, a predetermined amount of Bi ₂ Te ₃ is weighed, and these are used as raw materials.
A non-linear resistor was manufactured by the same manufacturing method as in the first embodiment.

The non-linear resistor of this embodiment has a varistor voltage of 15 to 120 V / mm as in the first embodiment.
The discharge withstand characteristic is also good.

FIG. 4 shows the non-linearity of the non-linear resistor obtained as described above.

As is clear from the results shown in FIGS. 3 and 4, it can be seen that the non-linear characteristic is further improved as compared with the first embodiment.

The reason why the non-linear characteristic is improved in the fifth embodiment of the present invention is considered as follows. Titanium telluride (TiTe ₂ ) as an additive,
By including bismuth telluride (Bi ₂ Te ₃ ), Te can be easily solid-dissolved in the grain boundaries, and a barrier that causes non-linear characteristics is formed. Therefore, titanium telluride (TiTe)
₂ ) By adding bismuth telluride (Bi ₂ Te ₃ ), excellent current-voltage characteristics can be obtained.

In the present embodiment, Bi ₂ O ₃ , TiO ₂ ,
The case where CoO, MnCo ₃ , and NiO are each contained at 1 mol% is shown, but when titanium telluride (TiTe ₂ ) is added, it is converted to bismuth oxide Bi ₂ O ₃ of 0.1%.
˜5.0 mol%, 0.1 to 3.0 mol% in terms of titanium oxide (TiO ₂ ), 0.1 to 5.0 mol% in terms of cobalt oxide (CoO), manganese oxide (Mn
It was confirmed that similar effects can be obtained when 0.1 to 5.0 mol% in terms of O) and 0.1 to 5.0 mol% in terms of nickel oxide (NiO) are contained.

Further, bismuth telluride (Bi₂Te₃)
When added, bismuth oxide (Bi ₂O₃)
0.1 to 3.0 mol%, titanium oxide (TiO₂)
Calculated 0.1-5.0 mol%, cobalt oxide (Co
0.1 to 5.0 mol% converted to O), manganese oxide
0.1 to 5.0 mol% in terms of (MnO), nitric oxide
Converted to nickel (NiO) 0.1-5.0 mol% included
Confirmed that the same effect can be obtained even if it has
did.

Next explained is the sixth embodiment of the invention.

Bi ₂ O ₃ , TiO ₂ , and C are used as the main components ZnO.
1 mol% each of oO, MnCo ₃ , and NiO, TeO
₂ mol% of ₂ is weighed and these are used as raw materials. 1st below
In the manufacturing method similar to that of the embodiment of FIG.
℃, 1100 ℃, 1200 ℃, and 1250 ℃,
The temperature decreasing rate from 1000 ° C to 750 ° C is 50 ° C / h,
Sintered bodies were obtained at 100 ° C./h and 200 ° C./h.

For comparison, the rate of temperature decrease is 250 ° C.
/ H was obtained as a sintered body. Then, a non-linear resistor was manufactured by the same manufacturing method as in the first embodiment.

The non-linear resistor of this embodiment has a varistor voltage of 15 to 120 V / mm, as in the first embodiment.
And the non-linear characteristic was also good.

Table 6 shows the voltage application life characteristics and the non-linear characteristics of the non-linear resistor obtained as described above.

[0111]

[Table 6]

The voltage application life characteristics were measured under the same conditions as in the second embodiment. As is clear from the results shown in Table 6, the non-linear resistor of the present embodiment has a comparative example (No. 13).
It can be seen that compared with *), the voltage application life characteristics and non-linearity characteristics are better. Further, the relative intensity ratio of α phase and β phase of the crystal phase of the bismuth phase is 0.5 or more under the manufacturing conditions of the present embodiment, and the electric charge life characteristic and the nonlinear characteristic are improved.

In the comparative example, the intensity ratio is 0.2,
Charging life characteristics and non-linear characteristics deteriorate. Further, the crystal phase segregated at the triple points is produced under the manufacturing conditions of the present embodiment, so that ZnTiO ₂ is produced, and the electric charge life characteristic and the non-linear characteristic are improved.

As described above, the reason why a non-linear resistor having better discharge withstand characteristics and non-linear characteristics than those of the comparative example can be obtained in the present embodiment is considered as follows.

The nonlinear resistor according to the present invention is made of Bi ₂ O ₃
Is included. In the temperature decreasing process of firing, Bi ₂ O ₃ is
At 825 ° C, the liquid phase changes to the solid phase. In this process, by setting the temperature decrease rate to 50 to 200 ° C,
It is considered that this is because the α phase of the Bi ₂ O ₃ crystal phase in the sintered body increases and the structure becomes stable against thermal stress.

Further, in this process, ZnTiO ₂
Is generated at three points, abnormal grain growth can be controlled, a uniform resistance distribution can be obtained, and excellent non-linear characteristics can be obtained.

In the present embodiment, Bi ₂ O ₃ , TiO ₂ ,
CoO, MnCo ₃ , and NiO are each contained in an amount of 1 mol%, TeO ₂ is further contained in an amount of ₂ mol%, and the firing temperature is from 1050 ° C
Although an example in which the temperature lowering rate from 1250 ° C. and 1000 ° C. to 750 ° C. is 50 ° C./h to 200 ° C./h is shown,
Converted to Bi ₂ O ₃ , 0.1 to 5.0 mol%, TiO ₂
0.1 to 5.0 mol% in terms of CoO, 0.1 to 5.0 mol% in terms of CoO, 0.1 to MnO
5.0 mol%, 0.1 to 5.0 mo converted to NiO
1% content, 0.001 converted to TeO ₂
It was confirmed that the same effect was obtained even when the content was 3.0 mol%.

Further, rubidium in the above addition range,
Silver, thallium, cesium, and boron are each converted into rubidium oxide (Rb ₂ O), and 0.5 × 10.
^{-3 to} 20 × 10 ^-3 mol%, silver converted to silver oxide (Ag ₂ O) 0.5 × 10 ^{-3 to} 20 × 10 ^-3 mol%, thallium converted to thallium oxide (Tl ₂ O) 0.5 x 1
0 ^{−3 to} 20 × 10 ⁻³ mol%, 0.5 × 10 ^{−3 to} 20 × 10 ⁻³ in terms of cesium converted to cesium oxide (Cs ₂ O)
mol%, 5 when converted to boron oxide (B ₂ O ₃ )
It was confirmed that the same effect was obtained even when the content of x10 ^{-3 to} 20 x 10 ^-3 mol% was contained.

Next, a seventh embodiment of the present invention will be described.

Bi ₂ O ₃ , TiO ₂ and C are used as main components ZnO.
1 mol% each of oO, MnCo ₃ , and NiO, Te
₂ mol% of O ₂ is weighed and used as a raw material. Hereinafter, a sintered body was obtained by the same manufacturing method as in the first embodiment.

FIG. 5 shows the structure of such a sintered body.

In FIG. 5, the side surface portion of the obtained sintered body 1 is coated with a low melting point glass to obtain a side surface layer 2. Further, both ends of the sintered body 1 are polished, and aluminum is sprayed on the both ends to form the electrodes 3. Further, after brass is sprayed on the sprayed surface to form the electrode 4, the paste-like low melting point metal 5 is applied, the terminal metal fitting 6 is placed, and the terminal metal fitting 6 is put into an electric furnace to bond the terminal metal fitting at 300 ° C. Thus, a non-linear resistor as shown in the figure can be obtained.

According to the present invention, a more reliable product can be provided because the contact resistance and the number of parts are reduced by directly joining the terminal fittings which are conventionally fixed via a spring.

The low melting point metal of the present embodiment is shown in Table 7.
As shown in, a predetermined amount of Sn, Ag, and Zn, Cu, and Ti are weighed and blended.

[0125]

[Table 7]

As is clear from the results shown in Table 7 above, Sn, Ag, and Zn as raw materials of the low melting point metal,
Contains at least one of Cu and Ti, and has Sn of 70 to 9
9.8%, Ag 0.2 to 10%, Zn 0 to 10%,
It can be seen that when the Cu is out of the range of 0 to 10% and the Ti is out of the range of 0 to 10%, the adhesion strength with the terminal fitting is lowered.

In Table 7, No. 1 *, No. 5 *, No. 9
*, No. 10 *, No. 11 *, and No. 12 * are shown as comparative examples when one of the raw materials is out of the above range.

In this embodiment, Bi ₂ O ₃ , TiO ₂ ,
CoO, MnCo ₃ , and NiO are 1 mol% and T, respectively.
Although the case of containing ₂ mol% of eO ₂ is shown, it has been confirmed that the same effects can be obtained by applying the same to the nonlinear resistors shown in the above-mentioned respective embodiments.

Next, an eighth embodiment of the present invention will be described.

Bi ₂ O ₃ , TiO ₂ and C were added to the main component ZnO.
1 mol% each of oO, MnCo ₃ , and NiO, Te
₂ mol% of O ₂ is weighed and used as a raw material. Hereinafter, a sintered body is obtained by the same manufacturing method as in the first embodiment.

FIGS. 6 (a) and 6 (b) show a structure in which a terminal fitting and an insulating coating are provided on such a sintered body.

In FIG. 6A, after applying the conductive resin paste 5a containing Ag as a main component to the sintered body 1, the terminal metal fitting 6 is placed and baked at 150 ° C. 1 and bonded to obtain a non-linear resistor as shown.

In this embodiment, the conductive resin paste 5 is used.
By using a, baking can be performed at a low temperature, the effect of heat on the element body can be reduced, stable characteristics can be obtained, and a more reliable product can be provided.

Further, as shown in FIG. 6B, the outer periphery of the side surface and a part of the terminal fitting are covered with an insulating elastic member or an inorganic insulating material 7 containing aluminum orthophosphate as a main component to prevent contamination. It is possible to obtain a non-linear resistor having strong characteristics. Therefore, creeping on the surface can be prevented, and excellent discharge withstanding characteristics can be obtained.

In this embodiment, Bi ₂ O ₃ and Ti are used.
1 mol of O ₂ , CoO, MnCo ₃ , and NiO, respectively
%, The case where the terminal metal fitting 6 is joined to the sintered body 1 containing ₂ mol% of TeO ₂ is shown. However, the same can be applied to any of the nonlinear resistors manufactured in the above-described embodiments. , It has been confirmed that the same effect can be obtained.

[0136]

As described above, according to the present invention, it is possible to provide a non-linear resistor which has a small variation in resistance value even if it is upsized and which is excellent in discharge withstand characteristics and electric charge life characteristics, and a manufacturing method thereof. You can

[Brief description of drawings]

FIG. 1 is a sectional view showing a non-linear resistor according to a first embodiment of the present invention.

FIG. 2 is a graph showing non-linear characteristics of a non-linear resistor according to a third embodiment of the present invention.

FIG. 3 is a graph showing non-linear characteristics of a non-linear resistor according to a fifth example of the present invention.

FIG. 4 is a graph showing non-linear characteristics of another non-linear resistor according to the same embodiment.

FIG. 5 is a sectional view showing a non-linear resistor according to a seventh embodiment of the present invention.

6A and 6B are cross-sectional views showing a non-linear resistor according to an eighth embodiment of the present invention.

[Explanation of symbols]

1 ... Sintered body 2 ... Side insulator 3 ... Electrode 4 ... Brass electrode coating 5 ... Low melting point metal 5a ... Conductive paste 6 ... Terminal fittings 7 ... Insulating elastic member or inorganic insulating member

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hideyasu Ando             2-1, Ukishima-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa             Ceremony Company Toshiba Hamakawasaki Factory (72) Inventor Akiko Suyama             2-1, Ukishima-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa             Ceremony Company Toshiba Hamakawasaki Factory (72) Inventor Yoshiyasu Ito             2-4 Suehiro-cho, Tsurumi-ku, Yokohama-shi, Kanagawa               Toshiba Keihin Office (72) Inventor Hironori Suzuki             2-1, Ukishima-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa             Ceremony Company Toshiba Hamakawasaki Factory F-term (reference) 5E034 CA09 CB01 CC04 DA03 DB12                       DC03 DC04 DE01 DE04 DE05                       DE07

Claims (15)

[Claims] 1. Zinc oxide (ZnO) as a main component, and bismuth, titanium, cobalt, manganese, and nickel as auxiliary components are each converted into bismuth oxide (Bi ₂ O ₃ ) of 0.1 to 5.0 mol. %, 0.1 to 5.0 mol% in terms of titanium oxide (TiO ₂ ), cobalt oxide (Co
0.1 to 5.0 mol% in terms of O), 0.1 to 5.0 mol% in terms of manganese oxide (MnO), 0.1 to 5.0 mol% in terms of nickel oxide (NiO). A non-linear resistor which contains 0.001 to 3.0 mol% of tellurium in the form of tellurium oxide (TeO ₂ ). 2. The non-linear resistor according to claim 1,
0.5 × 10 ^-3 converted to rubidium oxide (Rb ₂ O)
˜20 × 10 ⁻³ mol% rubidium, silver oxide (Ag ₂
Converted to O) 0.5 × 10 ^{−3 to} 20 × 10 ⁻³ mol%
0.5 × 1 converted to thallium oxide (Tl ₂ O)
0 ^{−3 to} 20 × 10 ⁻³ mol% of thallium and 0.5 × 10 ^{−3 to} 20 × 10 ⁻³ in terms of cesium oxide (Cs ₂ O).
A non-linear resistor containing at least one component of 5 × 10 ^{−3 to} 20 × 10 ⁻³ mol% boron in terms of mol% cesium and boron oxide (B ₂ O ₃ ). 3. The non-linear resistance according to claim 1 or 2.
In the body, aluminum is replaced by aluminum oxide (Al₂
O₃) Converted to 0.5 x 10^-3~ 20 x 10 ^-3mol
% Non-linear resistor. 4. Zinc oxide as a main component, and as a sub-component,
Bismuth, titanium, cobalt, manganese, and nickel are each converted to bismuth oxide (Bi ₂ O ₃ ) to be 0.1 to 0.1.
5.0 mol%, 0.1 to 3.0 mol% in terms of titanium oxide (TiO ₂ ), 0.1 to 5.0 mol% in terms of cobalt oxide (CoO), manganese oxide (Mn)
0.1 to 5.0 mol% in terms of O) and 0.1 to 5.0 mol% in terms of nickel oxide (NiO),
Furthermore, titanium telluride (TiTe ₂ ) 0.001
A non-linear resistor containing 3.0 mol%. 5. Zinc oxide as a main component, and as a secondary component,
Bismuth, titanium, cobalt, manganese, and nickel are each converted to bismuth oxide (Bi ₂ O ₃ ) to be 0.1 to 0.1.
3.0 mol%, 0.1 to 5.0 mol% in terms of titanium oxide (TiO ₂ ), 0.1 to 5.0 mol% in terms of cobalt oxide (CoO), manganese oxide (Mn)
0.1 to 5.0 mol% in terms of O) and 0.1 to 5.0 mol% in terms of nickel oxide (NiO),
Furthermore, it is converted to bismuth telluride (Bi ₂ Te ₃ ) to be 0.
001-3.0 mol% is contained, The nonlinear resistor characterized by the above-mentioned. 6. The nonlinear resistor according to claim 1, wherein the bismuth crystal phase contained is an α phase or a β phase, and the relative intensity ratio α / β thereof. Is 0.5 or more, a non-linear resistor. 7. The non-linear resistor according to claim 1, wherein the element has a porosity of 10% or less. 8. Zinc oxide which is a main component and bismuth, titanium, cobalt, manganese, nickel and tellurium which are sub-components which are weighed in predetermined amounts are used as raw materials, and the raw materials are mixed with an organic binder by a mixing device, This mixture is made into a granulated powder having a predetermined particle size by a granulating means, the granulated powder is put into a mold and pressurized to give a molded product having a predetermined shape, and then this molded product is fired at a predetermined temperature. A method for manufacturing a non-linear resistor, characterized in that a sintered body is obtained by applying a coating to the side surface of the sintered body, and then a conductive material is sprayed on both end surfaces to form electrodes. 9. Zinc oxide which is a main component and bismuth, titanium, cobalt, manganese, nickel and tellurium which are auxiliary components which are weighed in predetermined amounts are used as raw materials, and rubidium, silver and thallium which are weighed in addition amounts. , Cesium as a raw material, these raw materials are mixed with an organic binder by a mixing device, and the mixture is made into a granulated powder having a predetermined particle diameter by a granulating means. After that, the molded body is fired at a predetermined temperature to obtain a sintered body, the side surfaces of this sintered body are coated, and then conductive materials are sprayed on both end surfaces to form electrodes. A method of manufacturing a non-linear resistor characterized by the above. 10. The method for producing a non-linear resistor according to claim 9, wherein the rubidium, silver, thallium and cesium components are added in the form of a salt solution. 11. The method for producing a non-linear resistor according to claim 10, wherein the solution of the rubidium salt, silver salt, thallium salt or cesium salt is a solution of nitrate. . 12. The method for producing a non-linear resistor according to claim 8 or 9, wherein a firing temperature of the molded body is 10
A non-linear resistor and a method for manufacturing the same, wherein the temperature lowering rate from 50 to 1250 ° C, 1000 ° C to 750 ° C is 50 to 200 ° C / h, and the varistor voltage is 15 to 120V / mm. 13. The method for manufacturing a non-linear resistor according to claim 8 or 9, wherein brass is sprayed on opposite end faces of the non-linear resistor, and the metal terminal is joined with a low melting point metal. Body and its manufacturing method. 14. The method of manufacturing a nonlinear resistor according to claim 13, wherein the low melting point metal includes Sn, Ag, and at least one selected from Zn, Cu, and Ti.
0-99.8%, Ag, 0.2-10%, Zn 0-1
0%, Cu 0-10%, Ti 0-10%, The manufacturing method of the non-linear resistor characterized by the above-mentioned. 15. The method for manufacturing a non-linear resistor according to claim 8 or 9, wherein terminal metal fittings are joined to the opposite end faces with a conductive resin material. .