JPH10241910A - Nonlinear resistor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonlinear resistor which can be lowered in varistor voltage, can be increased in thickness and size, and has an excellent discharge withstand current rating characteristic and voltage-applied life characteristic and the resistance value of which does not fluctuate much even when the size of the resistor is increased. SOLUTION: A resistor contains a zinc oxide as a main component and 0.1-5.0mol% bismuth when converted into bismuth oxide (Bi2 O3 ), 0.1-5.0mol% antimony when converted into antimony oxide (Sb2 O3 ), and 0.1-0.5mol% titanium when converted into titanium oxide (TiO2 ) as sub-components and has a varistor voltage (V1m A) of 20-150V/mm.

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 used for an arrester, a surge absorber and the like, and more particularly to a non-linear resistor mainly composed of zinc oxide.

[0002]

2. Description of the Related Art Lightning arresters and surge absorbers are generally used to suppress abnormal voltages in electric power systems and electronic equipment circuits and to protect electric power systems and electronic equipment. The lightning arrester and surge absorber employ a non-linear resistor that protects a system or a circuit by exhibiting insulation characteristics at a normal voltage and exhibiting low resistance characteristics when an abnormal voltage is applied. .

[0003] A method of manufacturing this nonlinear resistor is roughly as follows. The raw material contains {nO as a main component and Bi ₂ O ₃ , Sb ₂ O ₃ , Co}, ΔnO as sub-components.
O, Cr ₂ O _3, etc. are added, these raw materials are sufficiently mixed with water and an organic binder, granulated by a spray drier or the like, and molded and sintered. Thereafter, a high-resistance substance is applied to the side surface of the sintered body to prevent creeping flashes, and refired to form a high-resistance layer. Then, both ends of the sintered body are polished and electrodes are attached, and a non-linear resistor is manufactured.

[0004] In recent years, electric power systems have been increasing in capacity to reduce transmission costs. For example, a non-linear resistor used in a lightning arrester needs to process an extremely large surge energy, and measures such as increasing the capacity of the non-linear resistor and increasing the number of parallel-connected resistors are used.

[0005] However, the increase in the number of parallel-connected elements is limited due to the problem of characteristics such as easy imbalance of current sharing, and the capacity of the non-linear resistor must necessarily be increased. However, the increase in the element diameter is limited by the diameter of the cylindrical container accommodating the element.

On the other hand, the thickness of the non-linear resistor is limited by the combination of the rising voltage (varistor voltage, V _{1 mA} ) of the non-linear resistor and the limit voltage of the surge arrester. The current varistor voltage of the non-linear resistor is 180 to 300 V / mm. However, if the varistor voltage can be reduced, the thickness of the non-linear resistor can be increased and the energy processing amount can be increased. Therefore, a nonlinear resistor having a low varistor voltage has been desired.

The shape of the non-linear resistor thus obtained has a diameter of 100 to 120 mm and a thickness of 20 to 45 mm. Another problem arises with such large non-linear resistors. That is, in the sintered body used for the large-sized non-linear resistor, abnormal grain growth of ΔnO crystal grains occurs due to the partial non-uniformity of the sintering temperature during sintering, and the resistance value varies. It will be easier. Further, there is a problem that current concentrates on a portion having a low resistance, resulting in a decrease in withstand voltage characteristics and a decrease in life characteristics.

[0008] The V _1mA was lower voltage, a method that 10~50V / mm are known as a method of manufacturing an electronic circuit for the non-linear resistor (Kokoku No. 5-52642). But,
This method is limited to small non-linear resistors for electronic components, for example, those having a diameter of 10 mm and a thickness of 1 mm, and cannot be directly applied to large non-linear resistors for electric power. There was a problem.

[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 due to the limit voltage of the surge arrester. In addition, when the size is increased, there is a problem that a variation in the resistance value is partially generated in the sintered body, and the discharge withstand characteristic and the charging life characteristic are deteriorated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and can reduce a varistor voltage, increase the thickness of a non-linear resistor, increase the size of the non-linear resistor, and provide a non-linear resistor excellent in discharge capability. The purpose is to provide the body.

Another object of the present invention is to provide a non-linear resistor which has a small variation in resistance value even when the size of the resistor is increased, and which is excellent in discharge withstand characteristics and charging life characteristics.

[0012]

To achieve the above object, a non-linear resistor according to the first aspect of the present invention comprises:
Zinc oxide as a main component and as the minor component, in terms of bismuth bismuth oxide (Bi ₂ O ₃₎ 0.1~5.0mol
%, 0.1 to 5.0 mol% of antimony in terms of antimony oxide (Sb ₂ O _3), and containing respectively 0.1 to 5.0 mol% of titanium in terms of titanium oxide (TiO _2), varistor voltage (V _1mA) is, 20~150V / mm
It is characterized by being.

In the nonlinear resistor according to the second aspect of the present invention, cobalt is converted to CoΟ as an auxiliary component in the range of 01 to 5.0.
mol%.

According to a third aspect of the present invention, in the nonlinear resistor, manganese is converted into ΔnO as a sub-component in the range of 0.1 to 5.0.
It is characterized by containing 0 mol%.

The nonlinear resistor according to the invention of claim 4 is characterized in that nickel is converted to NiO as a sub-component in the range of 0.1 to 5.0.
It is characterized by containing 0 mol%.

In the nonlinear resistor according to the fifth aspect of the present invention, aluminum as an auxiliary component is converted to 0.12 in terms of A1 ₂ O ₃ .
It is characterized by containing 5 × 10 ^{−3 to} 20 × 10 ⁻³ mol%.

The nonlinear resistor according to the invention of claim 6 is characterized in that boron is converted into B ₂ O ₃ as a sub-component in an amount of 0.5 × 10 3
^{-3 to} 20 × 10 ^-3 mol%.

In the nonlinear resistor according to the invention of claim 7, silver is converted into Ag ₂ O as an auxiliary component in an amount of 0.5 × 10 ⁻³ to 0.5 × 10 ⁻³ .
It is characterized by containing 20 × 10 ⁻³ mol%.

The nonlinear resistor according to the invention of claim 8 is characterized in that the bismuth contained forms cubic bismuth oxide.

The present invention has been made based on the following findings.

That is, the resistance of the non-linear resistor mainly composed of ΔnO appears at the grain boundaries of the ΔnO particles. Therefore, the resistance of the nonlinear resistor is determined by the reciprocal of the number of grain boundaries, that is, the particle size of the ΔnO particles. The growth of the ΖnO particles is affected by the added secondary components. That is, Bi ₂ O ₃ becomes a liquid phase during sintering, dissolves {n}, and promotes its movement, thereby promoting the growth of {n} crystal grains. TiO ₂ promotes the growth of ΔnO crystal particles by increasing the solubility of ΔnO. The two subcomponents promote the growth of the ΔnO crystal grains, and can lower the varistor voltage (V _1mA ) of the nonlinear resistor. However, merely promoting the growth of ZnO crystal particles generates ZnO crystal particles that grow abnormally. Sb ₂ O ₃ is added to control the abnormal grain growth. Sb ₂ O ₃ forms Zn ₇ Sb ₂ O _{12 type} spinel particles during sintering. The spinel particles alienate the growth of the ZnO crystal particles and suppress abnormal grain growth.
The growth of ZnO crystal grains can be controlled. It is considered that the ZnO crystal particles can be grown uniformly due to the effects of these subcomponents, so that a varistor voltage (V _{1 mA} ) can be reduced and a nonlinear resistor having excellent discharge withstand capability can be obtained.

In the present invention, the conventional example (for example,
234716) does not contain antimony (Sb) or chromium (Cr), but these are not affected during firing.
Reacts with O to form a composite oxide. Since these composite oxides hinder the growth of ΔnO crystal grains, the varistor voltage (V _1mA ) cannot be reduced. In the present invention, it was confirmed that since these two components were not contained, good {n} crystal grains could be obtained, and a non-linear resistor having a low varistor voltage (V _{1 mA} ) and good withstand characteristics could be obtained. ing.

It should be noted that the varistor voltage (V _{1 mA} ) is set to 20 to ₁
The reason for setting the voltage to 50 V / mm is considered as follows. When the varistor voltage (V _{1 mA} ) is lower than 20 V / mm, the element becomes large in order to obtain a predetermined limit voltage as an arrester, and the above-mentioned sub-components Bi ₂ O ₃ , Sb ₂ O ₃ and Ti
This is because it is difficult to obtain a uniform sintered body even if O ₂ is added. If the varistor voltage (V _1mA ) exceeds 150 V / mm, the thickness of the non-linear resistor cannot be sufficiently increased, and the discharge resistance cannot be improved.

The growth of {n} crystal grains can also be promoted by raising the firing temperature or increasing the firing time. Therefore, the varistor voltage (V _{1 mA} ) can be adjusted to 20 to 15 by appropriately selecting the firing time and the firing temperature.
It can be 0 V / mm.

Incidentally, bismuth as a sub-component is 0.1 to 5.0 mol% in terms of Bi ₂ O ₃ , and antimony is Sb ₂ O 3
₃ in terms of 0.1 to 5.0 mol%, titanium, TiO ₂
The reason for the 0.1 to 5.0 mol% in terms of the contrast of these V _{5 kA} and V _1mA is within range is good and 1.6 or less, Outside this, non-linear characteristics is poor It is because it becomes.

Cobalt becomes Co ²⁺ and forms a solid solution in ΔnO crystal particles. Co ²⁺ exists near the grain boundaries of the {n} particles, and forms a barrier that causes the development of nonlinear characteristics. For this reason, it is considered that the addition of cobalt improves the nonlinear characteristics. If the addition amount of CoO is less than 0.1 mol%, the addition amount is small, and the effect of improving the nonlinear characteristics is small. When the content exceeds 5.0 mol%, it is considered that the amount of Co ²⁺ increases, the resistance at the grain boundary decreases, and the nonlinear characteristics deteriorate.

Manganese becomes Δn ²⁺ and forms a solid solution in the ΔnO crystal particles. Like Co ^2+, Μn ²⁺ exists near the grain boundary of ΖnO particles and forms a barrier that causes the development of nonlinear characteristics. Hereinafter, the reason why the nonlinear characteristics are improved is that CoO
Is considered to be substantially the same as the case where is added.

Nickel becomes Ni ²⁺ and forms a solid solution in the ΔnO crystal particles. Like Co ^2+, Ni ²⁺ exists near the grain boundary of the ΖnO particles, and forms a barrier that causes the development of nonlinear characteristics. Hereinafter, the reason why the nonlinear characteristics are improved is that CoΟ
Is considered to be substantially the same as the case where is added.

Aluminum becomes A1 ³⁺ and forms a solid solution in the ΔnO crystal particles. Like Co ^2+, A1 ³⁺ exists near the grain boundary of the ΖnO particles and forms a barrier that causes the development of nonlinear characteristics. It is considered that the reason why the nonlinear characteristics are improved is substantially the same as the case where CoΟ is added.

The amount of Al ₂ O ₃ added was 0.5 × 10
^The reason for setting ^{-3 to} 20 × 10 ⁻³ mol% is that if the addition amount of Al ₂ O ₃ is less than 0.5 × 10 ⁻³ mol%, the addition amount is small,
This is because the effect of improving the charging life characteristic is small.
If the amount exceeds 0 × 10 ⁻³ mol%, the amount of Al ₂ O ₃ increases, the resistance of the nonlinear resistor decreases, and the nonlinear resistance characteristics deteriorate.

It is considered that boron becomes B ²⁺ after sintering, exists between lattices of ΔnO, and inhibits the movement of ions.
For this reason, it is considered that the charging service life characteristics are improved. In addition, the addition amount of B ₂ O ₃ is 0.5 × 10 ^{−3 to} 20 × 10
^-3 mol% is because the amount of B ₂ O ₃ added is 0.5 × 10
^{If the} amount is less than ^-3 mol%, the amount of addition is small, and the effect of improving the application life characteristics is small. If the amount exceeds 20 × 10 ^-3 mol%, the amount of B ₂ O ₃ increases. This is because the resistance of the non-linear resistor decreases and the non-linear characteristics deteriorate.

Also, during application of power, it is considered that the electric characteristics of the non-linear resistor change because the ions dissolved in the ZnO crystal grains move by applying a high voltage to the non-linear resistor. However, silver becomes Αg ⁺ and exists between the lattices of ΖnO, which is considered to inhibit the movement of ions. For this reason, it is considered that the charging life property is improved by adding silver. The amount of Ag ₂ O added was 0.5 × 10 ^{−3 to} 20 ×
The reason for setting it to 10 ⁻³ mol% is that the addition amount of Ag ₂ O is 0.5
× is less than 10 ^-3 mol%, less amount is because a small effect of voltage application life characteristics improved, also, 20 × 10 ^-3 mo
If the amount exceeds 1%, the amount of Ag ₂ O increases, the resistance of the non-linear resistor decreases, and the non-linear characteristics deteriorate.

As described above, since the nonlinear resistor according to the first aspect contains zinc oxide as a main component and bismuth, antimony and titanium as subcomponents, the {n} crystal particle diameter can be uniformly increased. it can. Further, since the varistor voltage is set to 20 to 150 V / mm, the thickness of the non-linear resistor can be increased, and the discharge withstand characteristics can be improved.

The non-linear resistor according to any one of claims 2 to 5 contains cobalt, manganese, nickel, or aluminum. As a result, excellent non-linear characteristics can be obtained.

In the non-linear resistor according to the sixth or seventh aspect, by containing silver or boron, it is possible to obtain excellent current application life characteristics.

In the non-linear resistor according to the eighth aspect, since the bismuth contained forms cubic bismuth oxide, excellent charging life characteristics can be obtained.

[0037]

Embodiments of the present invention will be described below with reference to the drawings.

First Embodiment (Table 1, FIG. 1) Bi ₂ O ₃ , Sb ₂ O ₃ and TiO
_A predetermined amount of ₂ was weighed and used as a raw material. This raw material was mixed with water and an organic binder such as a dispersant in a mixing device.

Next, the mixture was spray-granulated to a predetermined particle size, for example, 100 μm using a spray dryer, for example. Then, the granulated powder was put into a mold, pressurized, and formed into a predetermined shape such as a disk to obtain a formed body. The molded body thus obtained is calcined at, for example, 500 ° C. in air in order to remove the added organic binders, and further calcined in air at 1200 ° C.
By firing at 2 ° C. for 2 hours, a sintered body 1 shown in FIG. 1 was obtained. Then, after applying an insulator having a high resistance by firing on the side surface of the sintered body 1, the firing is performed and the high resistance layer 2 is applied.
Was formed. Thereafter, both end faces of the sintered body 1 were polished, and aluminum was sprayed on the both end faces to form the electrodes 3. Thus, the non-linear resistor shown in FIG. 1 was obtained.

Next, the electrical characteristics of the nonlinear resistor obtained as described above will be described.

The varistor voltage (V) of these non-linear resistors
_{1 mA} ), discharge withstand characteristics, and non-linear characteristics are shown in Table 1. Table 1 shows the samples of the present embodiment (Examples 1 to 16),
Samples in which the composition of the components and the like were deviated (Comparative Examples 1 to 6)
Are shown. In addition, the discharge withstand characteristics are obtained by increasing the lightning impulse (4/10) current by 20
The current value applied to the non-linear resistors and expressed by the current value that the non-linear resistors withstood. Also, adjust the thickness of the nonlinear resistor,
A discharge withstand test was performed with the same varistor voltage (V _{1 mA} ) for each non-linear resistor. Nonlinearity exhibited by the ratio V _5kA / V _1mA of the voltage V _{5 kA} and the varistor voltage (V _{1 mA)} that occurs at a current of 5 kA.

As is evident from the results shown in Table 1, the non-linear resistor of this embodiment has a varistor voltage (V _{1 mA} ) of 20 to 150 V / mm and a discharge withstand characteristic of about 80 kA in the conventional example. In contrast, in the present embodiment, about 120
It turns out that it is as good as kA or more.

Second Embodiment (FIG. 2) Next, a second embodiment of the present invention will be described.

The main component 、 nO includes Bi ₂ O ₃ and Sb ₂ O ₃
And 1 mol% of {i} ₂ and CoO were weighed in predetermined amounts to obtain raw materials. The manufacturing method is the same as in the first embodiment. Nonlinear resistor of this embodiment, like the first embodiment, V _{1 mA} is 20~150V / mm, discharge withstand current rating characteristic is good.

FIG. 2 shows the nonlinearity of the nonlinear resistor obtained as described above. Non-linear characteristics are _V5kA / _V1mA
Indicated by The horizontal axis indicates the amount of CoO addition on a logarithmic scale, and the vertical axis indicates the non-linear characteristic V _{5 kA} / V _{1 mA} . As is clear from the results shown in FIG. 2, the non-linear characteristics are further improved as compared with the first embodiment.

In this embodiment, Bi ₂ O ₃ , Sb ₂ O ₃
And TiO ₂ in an amount of 1 mol%, and
Although the case of containing 1 to 5.0 mol% is shown, Bi ₂ O ₃
The 0.1~5.0mol%, 0.1~5.0mo the Sb ₂ O ₃
l%, it was confirmed that the TiO ₂ 0.1 to 5.0 mol%, and the same effect with the case where CoO and containing 0.1 to 5.0 mol% is obtained.

Third Embodiment (FIG. 3) Next, a third embodiment of the present invention will be described.

The main component 、 nO is composed of Bi ₂ O ₃ and Sb ₂ O ₃
A predetermined amount of TiO ₂ and TiO ₂ were weighed at 1 mol%, and ΔnO was weighed as a raw material. The manufacturing method is the same as in the first embodiment. As in the first embodiment, the nonlinear resistor of the present embodiment can set V _1mA to 20 to 150 V / mm,
The discharge capability is also good.

FIG. 3 shows the nonlinearity of the nonlinear resistor obtained as described above. _V5kA / V for non-linear resistor
_Shown at _{1 mA} . The abscissa indicates the amount of added MnO on a logarithmic scale, and the ordinate indicates the non-linear characteristic V _{5 kA} / V _{1 mA} .

As is apparent from the results shown in FIG. 3, the non-linear characteristics are further improved as compared with the first embodiment.

In this embodiment, Bi ₂ O ₃ , Sb ₂ O ₃
And 1 mol% of ΤiO ₂ , respectively.
It has been described a case containing 5.0 mol%, 0.1 to 5.0 mol% of Bi ₂ O _3, 0.15~5.0mo the Sb ₂ O ₃
l%, the TiO ₂ 0.1~5.0mol%, 5.0mo the CoO
It was also confirmed that the same effect can be obtained in the case of containing 1% or less and ΔnO of 0.1 to 5.0 mol%.

Fourth Embodiment (FIG. 4) Next, a fourth embodiment of the present invention will be described.

Bi ₂ O ₃ , Sb ₂ O ₃
A predetermined amount of 1 mol% of TiO ₂ and TiO ₂ and a predetermined amount of NiΟ were weighed and used as raw materials. The manufacturing method is the same as in the first embodiment.

As in the first embodiment, the non-linear resistor of this embodiment has V _{1 mA} of 20 to 150 V / mm, and has good discharge withstand characteristics.

FIG. 4 shows the nonlinearity of the nonlinear resistor obtained as described above. Non-linear characteristics are _V5kA / _V1mA
Indicated by The abscissa indicates the amount of NiO added on a logarithmic scale, and the ordinate indicates the non-linear characteristic V _{5 kA} / V _{1 mA} . As is clear from the results shown in FIG. 4, the non-linear characteristics are further improved as compared with the first embodiment.

In this embodiment, Bi ₂ O ₃ , Sb
₂ O ₃ and TiO ₂ each containing 1 mol%, Ni
The case where O is contained in an amount of 0.1 to 5.0 mol% is shown.
i ₂ O ₃ of 0.1 to 5.0 mol%, 0.1 to the Sb ₂ O ₃
5.0 mol%, the TiO ₂ 0.1 to 5.0 mol%, the CoO 5.0 mol% or less, 5.0 mol of Myuenuomikuron%, and Ni
It has been confirmed that the same effect can be obtained also when Ο is contained in the range of 0.1 to 5.0 mol%.

Fifth Embodiment (FIG. 5) Next, a fifth embodiment of the present invention will be described.

Bi ₂ O ₃ , Sb ₂ O ₃
And 1 mol% of {i} ₂ and Al ₂ O ₃ were weighed in predetermined amounts to obtain raw materials. The manufacturing method is the same as in the first embodiment.

As in the first embodiment, the non-linear resistor of this embodiment has a V _{1 mA} of 20 to 150 V / mm, and has good discharge withstand characteristics.

FIG. 5 shows the nonlinearity of the nonlinear resistor obtained as described above. _V5kA / V for non-linear resistor
_Shown at _{1 mA} . The horizontal axis indicates the amount of Al ₂ O ₃ added on a logarithmic scale, and the vertical axis indicates the non-linear characteristic V _{5 kA} / V _{1 mA} . As is clear from the results shown in FIG. 5, the non-linear characteristics are further improved as compared with the first embodiment.

In this embodiment, Bi ₂ O ₃ , Sb
1 mol% each of ₂ O ₃ and TiO ₂ ,
_The case where 0.1 to 5.0 mol% of ₂ O ₃ is contained is shown, but 0.1 to 5.0 mol% of Bi ₂ O ₃ , 0.1 to 5.0 mol% of Sb ₂ O ₃ , and TiO ₂ are contained. 0.1-5.0 mol%,
CoO 5.0 mol% or less, {n} 5.0 mol% or less, N
iΟ is 5.0 mol% or less, and Al ₂ O ₃ is 0.5 × 1
It has been confirmed that the same effect can be obtained also when the composition contains 0 ^{-3 to} 20 × 10 ^-3 mol%.

Sixth Embodiment (FIG. 6) Next, a sixth embodiment of the present invention will be described.

Bi ₂ O ₃ , Sb ₂ O ₃
A predetermined amount of TiO ₂ and TiO ₂ were each weighed, and Δg ₂ O was weighed as a raw material. The manufacturing method is the same as in the first embodiment. For comparison, a non-linear resistor to which no Ag ₂ O was added was manufactured.

As in the first embodiment, the non-linear resistor of this embodiment has V _{1 mA} of 20 to 150 V / mm, and has good discharge withstand characteristics and non-linear characteristics.

FIG. 6 shows the life characteristics of the nonlinear resistor obtained as described above. The life characteristics were shown as the rate of change in the electric characteristics (voltage V _{10 μA} at a current value of 10 _μA ) after applying power for 500 hours at 120 ° C. with an _application rate of 100% to V _{1 mA} . On the horizontal axis, the addition amount of Ag ₂ O is shown on a logarithmic scale.
The vertical axis indicates the rate of change of _{V10 μA} . As is clear from the results shown in FIG. 6, the life characteristics are further improved as compared with the first embodiment.

In this embodiment, Bi ₂ O ₃ , Sb
Each containing 1 mol% of ₂ O ₃ and TiO ₂ ,
_{Although the} case where 0.5 × 10 ^{−3 to} 20 × 10 ⁻³ mol% of ₂ O is included is shown, Bi ₂ O ₃ is 0.1 to 5.0 mol%, Sb
₂ O ₃ of 0.1 to 5.0 mol%, the TiO ₂ 0.1 to 5.
0 mol%, CoO is 5.0 mol% or less, {n} is 5.0 mol%
Below, NiΟ is 5.0 mol% or less, and Al ₂ O ₃ is 2
It has been confirmed that the same effect can be obtained when the content is 0 × 10 ⁻³ mol% or less.

Seventh Embodiment (FIG. 7) Next, the seventh embodiment of the present invention
An embodiment will be described.

Bi ₂ O ₃ , Sb ₂ O ₃
A predetermined amount of each of 1 mol% and ΔiO ₂ and B ₂ O ₃ were weighed to obtain raw materials. The manufacturing method is the same as in the first embodiment. For comparison, a non-linear resistor to which B ₂ O ₃ was not added was also manufactured. The non-linear resistor of the present embodiment includes:
Similarly to the first embodiment, V _{1 mA} is 3.0~150V / mm, discharge withstand current rating characteristic is better with nonlinear resistance characteristics.

FIG. 7 shows the charging life characteristics of the non-linear resistor obtained as described above. The charging life characteristics are as follows:
At 120 ° C. and 100% _charging rate for V _{1 mA} , 500
It is shown by the rate of change of V _{10 μΑ} after the time charge. In the figure,
The horizontal axis is the logarithmic scale of the amount of B ₂ O ₃ added, and the vertical axis is V
The rate of change was _{10 μΑ} . As is clear from the results shown in FIG. 7, it is understood that the charging lifetime characteristic is improved as compared with the first embodiment.

In this embodiment, Bi ₂ O ₃ , Sb
₂ O _3, and TiO _2, respectively, wherein 1 mol%, B ₂
O _3, but shows the case containing ^{0.5 × 10 -3 ~20 × 10 -3} mol%, 0.1~5.0mol% of Bi ₂ O _3, Sb
₂ O ₃ of 0.1 to 5.0 mol%, the TiO ₂ 0.1 to 5.
0 mol%, CoO is 5.0 mol% or less, {n} is 5.0 mol%
Hereinafter, NiΟ is 5.0 mol% or less, and Al ₂ O ₃ is 20 × 1.
0 ^-3 mol% or less, and B ₂ O ₃ to 0.5 × 10 ^-3 to 20
It has been confirmed that the same effect can be obtained also when the composition contains × 10 ⁻³ mol%.

Eighth Embodiment (FIG. 8) Next, an eighth embodiment of the present invention will be described.

Bi ₂ O ₃ , Sb ₂ O ₃
And TlO ₂ were each weighed at 1 mol% to obtain raw materials.
The manufacturing method is substantially the same as that of the first embodiment, but in this embodiment, the obtained sintered body is further heat-treated at 450 to 500 ° C. Subsequently, a non-linear resistor was manufactured by a manufacturing method similar to that of the first embodiment after forming the side surface high resistance layer.
Further, for comparison, a non-linear resistor without heat treatment was manufactured.

The non-linear resistor obtained in this manner was subjected to Χ-ray diffraction measurement. As a result, cubic bismuth oxide was formed in the present embodiment, whereas single crystal was obtained in the comparative embodiment. It was confirmed that the clinic bismuth oxide was formed.

As in the first embodiment, the non-linear resistor of this embodiment has V _{1 mA} of 20 to 150 V / mm and good non-linear characteristics.

FIG. 8 shows the discharge withstand characteristics of the non-linear resistor obtained as described above. The discharge withstand characteristics were represented by the average value of the current that the non-linear resistor endured by applying a lightning impulse (4/10) current to 20 non-linear resistors while increasing the current value in order.

As is clear from the results shown in FIG. 8, the non-linear resistor of the present embodiment has better discharge withstand characteristics than the comparative example.

In this embodiment, the reason why a non-linear resistor having better discharge withstand characteristics than the comparative example can be obtained is considered as follows.

In the microstructure of the non-linear resistor, 10
It is formed of {nO crystal grains of about μm and a grain boundary layer surrounding the {n} crystal grains. In the comparative embodiment, the grain boundary layer was formed of monoclinic bismuth oxide, while in the present embodiment, it was recognized that the grain boundary layer was formed of cubic bismuth oxide. The strength of the nonlinear resistor is determined by the strength of the interface between the ΔnO crystal grains and the grain boundary layer. A destructive test was performed on this embodiment and a comparative example, and the strength was compared. As a result, it was confirmed that the interface strength between ΔnO and cubic bismuth oxide was more excellent.

As described above, according to the present embodiment, the mechanical strength of the nonlinear resistor is improved due to the presence of cubic bismuth oxide, and the nonlinear resistor can sufficiently withstand the thermal stress generated by applying a current. Therefore, it is considered that the discharge withstand characteristics were improved.

In this embodiment, Bi ₂ O ₃ , Sb ₂ O ₃
And TiO ₂ at 1 mol% each, and B ₂ O ₃ at 0.
Although the case where 5 × 10 ^{−3 to} 20 × 10 ⁻³ mol% is contained is shown, Bi ₂ O ₃ is 0.1 to 5.0 mol%, Sb ₂ O ₃ is 0.1 to 5.0 mol%, and TiO ₂ is contained. From 0.1 to 5.0 mol%,
CoO 5.0 mol% or less, MnO 5.0 mol% or less, Δ
iΟ is 5.0 mol% or less, and Al ₂ O ₃ is 20 × 10 ⁻³ mol%
Or less and the ^{_{B 2 O 3 20 × 10 -3}} ~20 × 10 -3 m
It has been confirmed that the same effect can be obtained when the content is less than ol%.

As described above, in the first to eighth embodiments, an oxide is used as a raw material. However, the present invention is not limited to this.
The same effects can be obtained with hydroxides, carbonates, and oxalates. The size of the compact and the sintered body can be appropriately selected.

[0082]

[Table 1]

[0083]

As described above, according to the present invention,
Includes zinc oxide as a main component, bismuth, antimony, and titanium as subcomponents, uniformly increases the ZnO crystal particle diameter, and increases the thickness of the non-linear resistor by setting the varistor voltage to 20 to 150 V / mm. Thus, it is possible to provide a non-linear resistor having improved discharge withstand characteristics.

Since the present invention further contains cobalt, manganese, nickel or aluminum as an auxiliary component, it is possible to provide a non-linear resistor excellent in non-linear characteristics.

The present invention can provide a non-linear resistor excellent in non-linear characteristics because it further contains silver or boron as a subcomponent.

The present invention can also provide a non-linear resistor excellent in life characteristics because bismuth contained forms body-centered cubic bismuth oxide.

[Brief description of the 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 second embodiment of the present invention.

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

FIG. 4 is a graph showing non-linear characteristics of a non-linear resistor according to a fourth embodiment of the present invention.

FIG. 5 is a graph showing non-linear characteristics of a non-linear resistor according to a fifth embodiment of the present invention.

FIG. 6 is a graph showing a charging life characteristic of a nonlinear resistor according to a sixth embodiment of the present invention.

FIG. 7 is a graph showing a charging life characteristic of a non-linear resistor according to a seventh embodiment of the present invention.

FIG. 8 is a graph showing discharge withstand characteristics of a nonlinear resistor according to an eighth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sintered body 2 High resistance layer 3 Electrode

Claims (8)

[Claims] 1. A composition comprising zinc oxide as a main component and subcomponents as
Bismuth oxide is converted to bismuth oxide (Bi ₂ O ₃ ) to be 0.1%.
1 to 5.0 mol% of antimony is replaced by antimony oxide (Sb ₂
O ₃ ) and 0.1 to 5.0 mol% in terms of titanium oxide (TiO ₂ ).
Each contains, varistor voltage (V _{1 m A)} is 20 to 1
A non-linear resistor having a voltage of 50 V / mm. 2. The nonlinear resistor according to claim 1, wherein cobalt is contained as an auxiliary component in an amount of 0.1 to 5.0 mol% in terms of cobalt oxide (CoO). 3. The nonlinear resistor according to claim 1, wherein manganese is contained as an accessory component in an amount of 0.1 to 5.0 mol% in terms of manganese oxide (MnO). 4. The non-linear resistor according to claim 1, wherein nickel is contained as a minor component in an amount of 0.1 to 5.0 mol% in terms of nickel oxide (NiO). 5. An aluminum oxide (Al ₂ O ₃ ) conversion from 0.5 × 10 ⁻³ to 2 as an auxiliary component.
5. The non-linear resistor according to claim 1, which contains 0 × 10 ⁻³ mol%. 6. Boron oxide (B) as a sub-component
0.5 × 10 ^{-3 to} 20 × 10 ^-3 mol% in terms of ₂ O ₃ )
The nonlinear resistor according to claim 1, wherein the resistor is contained. 7. Silver is used as a sub-component as silver oxide (Ag ₂ Ο).
The non-linear resistor according to claim 1, wherein the non-linear resistor contains 0.5 × 10 ^{−3 to} 20 × 10 ⁻³ mol% in terms of. 8. The nonlinear resistor according to claim 1, wherein the bismuth contained forms cubic bismuth oxide.