JPS622442B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a sintered bulk voltage nonlinear resistance element whose main component is zinc oxide and which has excellent thermal runaway life during surges. BACKGROUND ART Voltage nonlinear resistance elements (hereinafter referred to as varistors) are widely used in overvoltage protection elements and lightning arresters.
The voltage V-current I characteristic of the varistor is expressed as I=(V/C). However, C is a constant corresponding to resistance,
α is called the voltage nonlinear index. In one step, the characteristics of the varistor are expressed by α and the varistor voltage, which is the voltage at a certain current. α is usually 0.1~
Determined from voltage-current characteristics at 1mA/ ^cm2 .
Further, for convenience, the varistor voltage is often expressed as the terminal voltage (V _1nA ) when a current of 1 mA flows. As a varistor, the varistor voltage is within an appropriate range (usually several 10 to several 100 V per mm of thickness).
, and the larger α is, the more desirable it is. Furthermore, when used in overvoltage protection elements or lightning arresters, the lower the limiting voltage characteristic (usually expressed as the ratio of the voltage at _XA to the _varistor voltage V The larger the impact current (expressed as the value of the impulse current at which the rate of change of the varistor voltage remains within the allowable range even after several applications) is more suitable. Furthermore, from the viewpoint of reliability, it is desirable to have a material that is stable against changes in temperature and environment. For baristas, silicon carbide is baked and hardened at high temperatures.
SiC varistors and ZnO varistors, whose sintered bodies mainly composed of zinc oxide exhibit voltage nonlinearity (bulk voltage nonlinearity), are well known. but,
When considering overvoltage protection devices and lightning arresters, ZnO varistors are superior in almost all of the above characteristics.
ZnO varistors are superior to SiC varistors, and ZnO varistors are now mainly used. ZnO varistors are made by mixing the main component ZnO with small amounts of bismuth oxide (Bi ₂ O ₃ ), cobalt oxide (Co ₂ O ₃ ), manganese oxide (MnO ₂ ), etc. After molding, the mixture is heated to 1000°C to 1400°C. It is obtained by sintering. ZnO varistors made in this way have α values of 30 to 50 or more, compared to conventional SiC varistors of 3 to 7, and have become the mainstream for overvoltage protection devices. There is. In particular, when used as a lightning arrester, it is thought that it can be applied as a so-called gear press arrester without connecting the discharge gap in series.
However, in order to use it as a gear press arrester, there are problems that must be further improved. In other words, since it is a gear press, ZnO is constantly
A voltage is applied to the varistor, which causes the element to deteriorate and cause thermal runaway. Among these, the most important problem from a practical standpoint is not only the applied voltage but also the thermal runaway life when surge current is repeatedly applied in addition to it. When using a ZnO varistor as a gear press arrester, the varistor voltage of the element is usually designed so that the peak value of the applied voltage is 50 to 80% of the varistor voltage. Therefore, for example, for a 60KV lightning arrester, the varistor voltage should be
Runs at 120KV to 75KV. Furthermore, in Japan, there are about 10 to 30 thunderstorm days a year, depending on the location, and each time a surge voltage is applied to the lightning arrester, a surge current flows. Assuming that one lightning strike causes about 10 shock currents, in a year
A surge current will be applied approximately 100 to 300 times. Since lightning arresters usually require a lifespan of 20 years or more, a total of 2,000 to 6,000 surge currents will be applied to the applied voltage of 60KV. The average surge current is considered to be about 100A with a waveform of 8 x 20μS, so when used as a gear press arrester, the surge current of 2000 to 6000 times at 100A will reach the AC applied voltage of 50 to 80% of the varistor voltage. It is necessary that thermal runaway does not occur even if heavy loads are applied. However, although conventional ZnO varistors are excellent in the above-mentioned a, limiting voltage characteristics, surge resistance, and stability against changes in environmental conditions,
There was no one that had a sufficient thermal runaway life under the conditions that a surge current would be added to the applied voltage as just described. In view of the above problems, the present invention aims to propose a voltage nonlinear resistance element with excellent thermal runaway life characteristics when subjected to surge current, and a method for manufacturing the same.
The details will be explained below along with the examples. Example 1 A small amount of Bi ₂ O ₃ , Co ₂ O ₃ , MnO ₂ ,
Sb ₂ O ₃ , Cr ₂ O ₃ , NiO, SiO ₂ , Al ₂ O ₃ , B ₂ O ₃ ,
Various amounts of MgO powder were added, thoroughly mixed, and compression molded into a disk shape with a diameter of 17.5 mm and a thickness of 2 mm at a pressure of 250 Kg/cm ² . Next, it was fired in air at 1230°C for 2 hours, and then both flat parts were polished and sprayed aluminum electrodes were provided. Varistor voltage (V _1nA /mm) per unit thickness of the device obtained in this way, a, voltage at 100A (V ₁₀
Limiting voltage ratio (V _100A /V _1nA ) expressed as the ratio of the voltage (V _1nA ) at _{0 A} ) and 1 mA, the change in varistor voltage after applying an impulse current of 1000 A twice in the same direction with a waveform of 8 × 20 μS. Surge resistance expressed as a rate, and shock current of 100A with a waveform of 8 x 20μS applied 40 times per hour in a constant temperature oven at 100℃ while applying a 60Hz alternating voltage with a peak value of 80% of the varistor voltage. Table 1 shows the results of measuring the time until thermal runaway (pulse overlapping thermal runaway life) when applied at a rate of . (Tables 1 to 4 are attached at the end of the specification.) The amount of ZnO in this example is the amount obtained by subtracting the mol% of the total amount of additives from 100 mol%. The same applies to each of the embodiments. As can be seen from Table 1, 0.1 to 3.0 mol%
_{Bi2O3 ,} 0.1-3.0 mol% _Co2O3 , _0.1-3.0 mol%
_MnO2 , 0.1-3.0 mol% _Sb2O3 , 0.05-1.5 mol% _{Cr2O3 ,} 0.1-3.0 _mol % NiO, 0.1-10.0
mol% _SiO2 , 0.0005-0.025 mol% _{Al2O3 ,}
0.005-0.3 mol% _B2O3 , _0.1-25.0 mol%
Sintered bodies containing MgO have a of 40 or more and V _100A /V _1n
It has the following characteristics: _A is 1.60 or less, surge resistance is -3.0% or less, and thermal runaway life is 170 hours or more. It is something that cannot be obtained. For example, without Bi ₂ O ₃ , a is less than 40, V _100A /
V _1nA is 1.60 or more, surge resistance is -3.0% or more, and pulse overload thermal runaway life is 170 hours or less.
The case where Co ₂ O ₃ or MnO ₂ is not included is the same as the case where Bi ₂ O ₃ is not included. Also, if there is no Sb ₂ O ₃ ,
The surge withstand capacity is -3.0% or more, and the thermal runaway life due to pulse overload is 170 hours or less. _{Cr2O3 or}
When NiO or SiO ₂ is not included, the properties are not as good as when Sb ₂ O ₃ is not included. Even when aluminum or boron is not included, the surge withstand capacity is -3.0% or more, and the thermal runaway life under pulse stress is 170 hours or less. If MgO is not included, the thermal runaway life due to pulse overload will be 170 hours or less. From the above results, the desired characteristics of this example are as follows.
It can only be obtained when all 10 components are present at the same time, and it cannot be obtained if even one of the components is missing. It can be seen that especially when aluminum and boron are present at the same time, the effect of improving the thermal runaway life due to pulse overlapping is large. In the absence of aluminum or boron, the thermal runaway life during pulsed heating was less than 10 hours. Example 2 A small amount of Bi ₂ O ₃ , Co ₂ O ₃ , MnO ₂ ,
Sb ₂ O ₃ , Cr ₂ O ₃ , NiO, SiO ₂ , Ga ₂ O ₃ , B ₂ O ₃ ,
Samples were prepared in the same manner as in Example 1 by adding MgO powder in various amounts. V _1nA /mm, a, V ₁₀₀ of the device obtained in this way
Table 2 shows the results of measuring _A /V _1nA , surge resistance, and thermal runaway life due to pulse overload. The measurement conditions are the same as in Example 1. Table 2 also shows the results when even one additive was missing as a comparative example. As can be seen from Table 2, 0.1 to 3.0 mol%
_{Bi2O3 ,} 0.1-3.0 mol% _Co2O3 , _0.1-3.0 mol%
_MnO2 , 0.1-3.0 mol% _Sb2O3 , 0.05-1.5 mol% _{Cr2O3 ,} 0.1-3.0 _mol % NiO, 0.1-10.0
mol% _SiO2 , 0.0005-0.25 mol% _{Ga2O3 ,}
0.005-0.3 mol% _B2O3 , _0.1-25.0 mol%
Sintered bodies containing MgO have a of 40 or more, V _100A / V _1nA
It has the characteristics of less than 1.60, surge resistance less than -3.0%, and a thermal runaway life of more than 170 hours under pulse stress, and these characteristics cannot be obtained even if any one of the above 10 additives is missing. It is something that cannot be done. For example, without Bi ₂ O ₃ , a is less than 40, V _100A /
V _1nA is 1.60 or more, surge resistance is -3.0% or more, and pulse overload thermal runaway life is 170 hours or less.
The case where Co ₂ O ₃ or MnO ₂ is not included is the same as the case where Bi ₂ O ₃ is not included. In addition, in the absence of Sb ₂ O ₃ , the surge resistance is −3.0% or more, and the thermal runaway life due to pulse overload is 170 hours or less. _{Cr2O3 _}
or Sb ₂ O ₃ if it does not contain NiO or SiO ₂
The properties are not as good as when it is not included. Even when gallium or boron is not included, the surge withstand capacity is -3.0% or more, and the thermal runaway life under pulse stress is 170 hours or less. If MgO is not included, the thermal runaway life due to pulse overload is 170 hours or less. From the above results, the desired characteristics of this example are as follows.
It can only be obtained when all 10 components are present at the same time, and it cannot be obtained if even one of the components is missing. In particular, it can be seen that when gallium and boron are present at the same time, the effect of improving the thermal runaway life due to pulse overlapping is significant. Pulse overload thermal runaway life without gallium or boron is 10
It was hot in less than an hour. Example 3 A small amount of Bi ₂ O ₃ , Co ₂ O ₃ , MnO ₂ ,
Sb ₂ O ₃ , Cr ₂ O ₃ , NiO, SiO ₂ , Al ₂ O ₃ , B ₂ O ₃ ,
Samples were prepared in the same manner as in Example 1 by adding MgO and Ag ₂ O powders in various amounts. V _1nA /mm of the device obtained in this way,
Table 3 shows the results of measuring a, V _100A /V _1nA , surge resistance, and pulse overload thermal runaway life.
The measurement conditions are the same as in Example 1. Table 3 also shows the results when even one additive was missing as a comparative example. As can be seen from Table 3, 0.1 to 3.0 mol%
_{Bi2O3 ,} 0.1-3.0 mol% _Co2O3 , _0.1-3.0 mol%
_MnO2 , 0.1-3.0 mol% _Sb2O3 , 0.05-1.5 mol% _{Cr2O3 ,} 0.1-3.0 _mol % NiO, 0.1-10.0
mol% _SiO2 , 0.0005-0.025 mol% _{Al2O3 ,}
0.005-0.3 mol% _B2O3 , _0.1-25.0 mol%
A sintered body containing MgO and 0.0005 to 0.3 mol% Ag ₂ O has an a of 50 or more, a V _100A /V _1nA of 1.60 or less, a surge withstand capacity of -3.0% or less, and a thermal runaway life due to pulse stress.
It has properties of over 210 hours, and such properties cannot be obtained even if any one of the 11 additives mentioned above is missing. For example, without Bi ₂ O ₃ , a is less than 50, V _100A /
V _1nA is 1.60 or more, surge resistance is -3.0% or more, and pulse overload thermal runaway life is 210 hours or less.
The case where Co ₂ O ₃ or MnO ₂ is not included is the same as the case where Bi ₂ O ₃ is not included. Also, if there is no Sb ₂ O ₃ ,
The surge withstand capacity is -3.0% or more, and the pulse overload thermal runaway life is 210 hours or less. When Cr ₂ O ₃ or NiO or SiO ₂ is not included, the properties are not as good as when Sb ₂ O ₃ is not included. Even when aluminum or boron is not included, the surge withstand capacity is -3.0% or more, and the thermal runaway life under pulse stress is 210 hours or less. If MgO is not included, the thermal runaway life due to pulse overload is 210 hours or less. Furthermore, even when silver is not included, the thermal runaway life due to pulse overload is 210 hours or less. From the above results, the desired characteristics of this example are as follows.
It can only be obtained when all 11 components are present at the same time, and it cannot be obtained if even one of the components is missing. In particular, it can be seen that when aluminum, silver, and boron are present at the same time, the effect of improving the thermal runaway life due to pulse overlapping is large. Example 4 A small amount of Bi ₂ O ₃ , Co ₂ O ₃ , MnO ₂ ,
Sb ₂ O ₃ , Cr ₂ O ₃ , NiO, SiO ₂ , Ga ₂ O ₃ , B ₂ O ₃ ,
Samples were prepared in the same manner as in Example 1 by adding MgO and Ag ₂ O powders in various amounts. V _1nA /mm of the device obtained in this way,
Table 4 shows the results of measuring a, V _100A /V _1nA , surge withstand capacity, and thermal runaway life due to pulse stress.
The measurement conditions are the same as in Example 1. Table 4 also shows the results when even one additive was missing as a comparative example. As can be seen from Table 4, 0.1 to 3.0 mol%
_{Bi2O3 ,} 0.1-3.0 mol% _Co2O3 , _0.1-3.0 mol%
_MnO2 , 0.1-3.0 mol% _Sb2O3 , 0.05-1.5 mol% _{Cr2O3 ,} 0.1-3.0 _mol % NiO, 0.1-10.0
mol% _SiO2 , 0.0005-0.025 mol% _{Ga2O3 ,}
0.005-0.3 mol% _B2O3 , _0.1-25.0 mol%
A sintered body containing MgO and 0.0005 to 0.3 mol% Ag ₂ O has an a of 50 or more, a V _100A /V _1nA of 1.60 or less, a surge withstand capacity of -3.0% or less, and a thermal runaway life due to pulse stress.
It has properties of over 210 hours, and such properties cannot be obtained even if any one of the 11 additives mentioned above is missing. For example, without Bi ₂ O ₃ , a is less than 50, V _100A /
V _1nA is 1.60 or more, surge resistance is -3.0% or more, and pulse overload thermal runaway life is 210 hours or less. The case where Co ₂ O ₃ or MnO ₂ is not included is the same as the case where Bi ₂ O ₃ is not included. In addition, in the absence of Sb ₂ O ₃ , the surge resistance is −3.0% or more, and the thermal runaway life due to pulse overload is 210 hours or less. _{Cr2O3 _}
or Sb ₂ O ₃ if it does not contain NiO or SiO ₂
The properties are not as good as when it is not included. Even when gallium or boron is not included, the surge withstand capacity is -3.0% or more, and the thermal runaway life under pulse stress is 210 hours or less. If MgO is not included, the thermal runaway life during pulse overload will be less than 210 hours.
Furthermore, even when silver is not included, the thermal runaway life due to pulse overload is 210 hours or less. From the above results, the desired characteristics of this example are as follows.
It can only be obtained when all 11 components are present at the same time, and it cannot be obtained if even one of the components is missing. In particular, it can be seen that when gallium, silver, and boron are present at the same time, the effect of improving the thermal runaway life due to pulse overlapping is large. Example 5 ZnO powder with material composition No.a-1 or No.b-1
Bi ₂ O ₃ , Co ₂ O ₃ , MnO ₂ , Sb ₂ O ₃ , Cr ₂ O ₃ , NiO,
A sample was prepared in the same manner as in Example 1 by adding SiO ₂ , MgO, Al ₂ O ₃ or Ga ₂ O ₃ and adding 0.3 weight of glass powder having the composition shown in Table 5 based on the total weight. . V of the device obtained in this way
Table 6 shows the surge resistance of _1nA /mm, a, and the thermal runaway life due to pulse stress.

【table】

[Table] As can be seen from Table 6, by adding boron together with a portion of silicon as borosilicate glass powder with the composition shown in Table 5, a is improved and the thermal runaway life during pulse overload is improved. . Compared to the case where boron was added alone, in all the compositions tested, the characteristics were improved by about 10 in a and about 10 hours in pulse overload thermal runaway life. Therefore, in this case, a is 50 or more and V _100
A /V _1nA is 1.60 or less, surge resistance is -3.0% or less,
A thermal runaway life of 180 hours or more can be obtained due to pulse overload. This effect was first achieved by adding vitrified boron.
Moreover, this effect can be seen in Bi ₂ O ₃ , Co ₂ O ₃ , MnO ₂ ,
Sb ₂ O ₃ , Cr ₂ O ₃ , NiO, SiO ₂ , Al ₂ O ₃ or
It can only be obtained when it is added to a material containing nine components, Ga ₂ O ₃ and MgO, and the above characteristics cannot be obtained even if one of the nine components is missing. This applies to each of the following examples (Example 6 to Example 14)
The same applies to Example 6 ZnO powder with material composition No. a-1 or No. b-1
Bi ₂ O ₃ , Co ₂ O ₃ , MnO ₂ , Sb ₂ O ₃ , Cr ₂ O ₃ , NiO,
A sample was prepared in the same manner as in Example 1 by adding SiO ₂ , MgO, Al ₂ O ₃ or Ga ₂ O ₃ and adding 0.3 weight of glass powder having the composition shown in Table 7 based on the total weight. . V of the device obtained in this way
Table 8 shows the surge resistance of _1nA /mm, a, and the thermal runaway life due to pulse overload.

【table】

[Table] As can be seen from Table 8, by adding boron together with bismuth and part of silicon as a bismuth borosilicate glass powder having the composition shown in Table 7, a is improved and the thermal runaway life is increased due to the pulse weight. Improved.
Compared to the case where boron was added alone, in all the compositions tested, the characteristics were improved by about 10 in a and by about 20 hours in pulse overload thermal runaway life. Therefore, in this case, a is 50 or more and V _100
A /V _1nA is 1.60 or less, surge resistance is -3.0% or less,
A thermal runaway life of 190 hours or more can be obtained due to pulse overload. This effect first appeared when boron was vitrified and added together with bismuth. Example 7 ZnO powder with material composition No.a-1 or No.b-1
Bi ₂ O ₃ , Co ₂ O ₃ , MnO ₂ , Sb ₂ O ₃ , Cr ₂ O ₃ , NiO,
A sample was prepared in the same manner as in Example 1 by adding SiO ₂ , MgO, Al ₂ O ₃ or Ga ₂ O ₃ and adding 0.3 weight of glass powder having the composition shown in Table 9 based on the total weight. . V of the device obtained in this way
Table 10 shows the surge resistance of _1nA /mm, a, and the thermal runaway life due to pulse overload.

【table】

[Table] As can be seen from Table 10, by adding boron together with a portion of silicon as a zinc borosilicate glass powder with the composition shown in Table 10, a is improved and the thermal runaway life during pulse overload is improved. Ru. Compared to the case where boron is added alone, in all compositions tested, a is about 10, and thermal runaway life due to pulse overlap is about 20.
Characteristics are being improved by about a certain amount of time. Therefore, in this case, a is 50 or more and V _100
A /V _1nA is 1.60 or less, surge resistance is -3.0% or less,
A thermal runaway life of 190 hours or more can be obtained due to pulse overload. This effect was first achieved by adding boron together with zinc in the form of vitrification. Example 8 ZnO powder with material composition No. a-1 or No. b-1
Bi ₂ O ₃ , Co ₂ O ₃ , Sb ₂ O ₃ , Cr ₂ O ₃ , NiO, SiO ₂ ,
Add MgO, Al ₂ O ₃ or Ga ₂ O ₃ and add glass powder having the composition shown in Table 11 based on the total weight.
A sample was prepared in the same manner as in Example 1 by adding 0.3 weight. V _1nA / of the device obtained in this way
Table 12 shows mm, a, surge withstand capacity, and thermal runaway life due to pulse stress.

【table】

[Table] As can be seen from Table 12, adding boron together with a portion of silicon as lead borosilicate glass powder with the composition shown in Table 11 improves a and improves the thermal runaway life under pulse stress. Ru. Compared to the case where boron was added alone, in all the compositions tested, the characteristics were improved by about 10 in a and by about 20 hours in pulse overload thermal runaway life. Therefore, in this case, a is 50 or more and V _100
A /V _1nA is 1.60 or less, surge resistance is -3.0% or less,
A thermal runaway life of 190 hours or more can be obtained due to pulse overload. This kind of effect first appeared when boron was added together with lead in the form of vitrification. Example 9 ZnO powder with material composition No. a-1 or No. b-1
Bi ₂ O ₃ , Co ₂ O ₃ , MnO ₂ , Sb ₂ O ₃ , Cr ₂ O ₃ , NiO,
A sample was prepared in the same manner as in Example 1 by adding SiO ₂ , MgO, Al ₂ O ₃ or Ga ₂ O ₃ and adding 0.3 weight of glass powder having the composition shown in Table 13 based on the total weight. . V of the device obtained in this way
Table 14 shows the surge resistance of _1nA /mm, a, and the thermal runaway life due to pulse overload.

【table】

[Table] As can be seen from Table 14, a is improved by adding boron together with cobalt, bismuth, and a part of silicon as a cobalt-doped bismuth borosilicate glass powder having the composition shown in Table 13. Thermal runaway life is improved. Compared to the case where boron was added alone, in all the compositions tested, a was about 10, and the thermal runaway life due to pulse weight was
The characteristics have been improved by about 20 hours. Therefore, in this case, a is 60 or more and V _100
A /V _1nA is 1.60 or less, surge resistance is -3.0% or less,
A thermal runaway life of 190 hours or more can be obtained due to pulse overload. This effect is caused by the combination of boron and cobalt.
This effect appeared for the first time when it was vitrified and added together with bismuth. Example 10 ZoO powder with material composition No.a-1 or No.b-1
Bi ₂ O ₃ , Co ₂ O ₃ , MnO ₂ , Sb ₂ O ₃ , Cr ₂ O ₃ , NiO,
A sample was prepared in the same manner as in Example 1 by adding SiO ₂ , MgO, Al ₂ O ₃ or Ga ₂ O ₃ and adding 0.3 weight of glass powder having the composition shown in Table 15 based on the total weight. . V of the device obtained in this way
Table 16 shows the surge resistance of _1nA /mm, a, and the thermal runaway life due to pulse overload.

【table】

[Table] As can be seen from Table 16, a is improved by adding boron and silver together with a part of silicon as a silver-doped borosilicate glass powder with a composition shown in Table 15. Runaway life is improved.
Compared to the case where boron and silver were added alone, in all compositions tested, the characteristics were improved by about 10 in a and by about 20 hours in pulsed thermal runaway life. Therefore, in this case, a is 60 or more and V _100
A /V _1nA is 1.60 or less, surge resistance is -3.0% or less,
A thermal runaway life of 230 hours or more can be obtained due to pulse overload. This kind of effect first appeared when boron and silver were added in the form of vitrification. Example 11 ZnO powder with material composition No. a-1 or No. b-1
Bi ₂ O ₃ , Co ₂ O ₃ , MnO ₂ , Sb ₂ O ₃ , Cr ₂ O ₃ , NiO,
A sample was prepared in the same manner as in Example 1 by adding SiO ₂ , MgO, Al ₂ O ₃ or Ga ₂ O ₃ and adding 0.3 weight of glass powder having the composition shown in Table 17 based on the total weight. . V of the device obtained in this way
Table 18 shows the surge resistance of _1nA /mm, a, and the thermal runaway life due to pulse overload.

【table】

[Table] As shown in Table 18, by adding boron and silver together with bismuth and part of silicon as a silver-doped bismuth borosilicate glass powder with the composition shown in Table 17, α is improved and the pulse Thermal runaway life is improved. α in all experimental compositions compared to when boron and silver were added alone.
The characteristics have been improved by about 10 hours, and the thermal runaway life due to pulse overload is about 30 hours. Therefore, in this case, α is 60 or more and V _100
A /V _1nA is 1.60 or less, surge resistance is -3.0% or less,
A thermal runaway life of 240 hours or more can be obtained due to pulse overload. This effect first appeared when boron and silver were vitrified and added together with bismuth. Example 12 ZnO powder with material composition No. a-1 or No. b-1
Bi ₂ O ₃ , Co ₂ O ₃ , MnO ₂ , Sb ₂ O ₃ , Cr ₂ O ₃ , NiO,
A sample was prepared in the same manner as in Example 1 by adding SiO ₂ , MgO, Al ₂ O ₃ or Ga ₂ O ₃ and adding 0.3 weight of glass powder having the composition shown in Table 19 based on the total weight. . V of the device obtained in this way
Table 20 shows _1nA /mm, α, surge withstand capacity, and thermal runaway life due to pulse stress.

【table】

[Table] As can be seen from Table 20, by adding boron and silver together with a part of silicon as silver-doped zinc borosilicate glass powder with a composition shown in Table 19, α
This improves the thermal runaway life due to pulse overload. Compared to the case where boron and silver were added alone, in all the compositions tested, the characteristics were improved by about 10 in α and by about 30 hours in pulsed thermal runaway life. Therefore, in this case, α is 60 or more and V _100
A /V _1nA is 1.60 or less, surge resistance is -3.0% or less,
A thermal runaway life of 240 hours or more can be obtained due to pulse overload. This effect first appeared when boron and silver were vitrified and added together with zinc. Example 13 ZnO powder with material composition No. a-1 or No. b-1
Bi ₂ O ₃ , Co ₂ O ₃ , MnO ₂ , Sb ₂ O ₃ , Cr ₂ O ₃ , NiO,
A sample was prepared in the same manner as in Example 1 by adding SiO ₂ , MgO, Al ₂ O ₃ or Ga ₂ O ₃ and adding 0.3 weight of glass powder having the composition shown in Table 21 based on the total weight. . V of the device obtained in this way
Table 22 shows _1nA /mm, α, surge withstand capacity, and thermal runaway life due to pulse stress.

【table】

[Table] As can be seen from Table 22, by adding boron and silver together with a portion of silicon as silver-doped lead borosilicate glass powder with the composition shown in Table 21, α is improved and the pulse becomes heavier. Thermal runaway life is improved. Compared to the case where boron and silver were added alone, in all the compositions tested, the characteristics were improved by about 10 in α and by about 30 hours in pulsed thermal runaway life. Therefore, in this case, α is 60 or more and V _100
A /V _1nA is 1.60 or less, surge resistance is -3.0% or less,
A thermal runaway life of 240 hours or more can be obtained due to pulse overload. This effect first appeared when boron and silver were added together with lead in a vitrified form. Example 14 ZnO powder with material composition No. a-1 or No. b-1
Bi ₂ O ₃ , Co ₂ O ₃ , MnO ₂ , Sb ₂ O ₃ , Cr ₂ O ₃ , NiO,
A sample was prepared in the same manner as in Example 1 by adding SiO, MgO, Al ₂ O ₃ or Ga ₂ O ₃ and adding 0.3 weight of glass powder having the composition shown in Table 23 based on the total weight. V of the device obtained in this way
Table 24 shows the surge resistance of _1nA /mm, a, and the thermal runaway life due to pulse stress.

【table】

[Table] As you can see from Table 24, boron and silver can be replaced by cobalt,
By adding silver and cobalt doped with bismuth borosilicate glass powder having a composition as shown in Table 23 together with a part of bismuth and silicon, α is improved and the thermal runaway life due to pulse stress is improved. Compared to the case where boron and silver were added alone, all of the tested compositions improved the properties by about 20 in α and by about 30 hours in thermal runaway life due to pulse overload. Therefore, in this case, α is 70 or more and V _100
A /V _1nA is 1.60 or less, surge resistance is -0.3% or less,
A thermal runaway life of 240 hours or more can be obtained due to pulse overload. This effect first appeared when boron and silver were vitrified and added together with cobalt and bismuth. In the above examples, oxides were used, but not only oxides but also halides, for example, as long as they become oxides after sintering.
It is not limited to nitrates, and the effects of the present invention are not impaired in any way even if they are added in the form of halides, nitrates, sulfides, or acetates. The device according to the present invention has α, V _100A /
It has excellent V _1nA surge resistance and thermal runaway life during pulse overload, and is therefore particularly useful when used as a gear press arrester. The figure shows an example of the structure of a typical lightning arrester using the element according to the present invention. In the figure, 1 is a voltage nonlinear resistance element, 2a and 2b are a pair of electrodes provided on the voltage nonlinear resistance element, 3 is a high voltage side electrical terminal electrically connected to one electrode 2a, and 4 is the other electrode. A ground side electric terminal electrically connected to the electrode 2b, 5 an insulating container, 6 a spring for holding the voltage nonlinear resistance element, and 7 a conductor connecting one electrode 2a and the high voltage side electric terminal 3. It is. By creating a lightning arrester with a simple structure that does not use a gap in this way, a small and lightweight lightning arrester can be obtained. Also, in terms of characteristics, there is no discharge delay or follow-on current that is seen in gap type types. Furthermore, compared to lightning arresters using conventional ZnO varistors, it has the advantage of superior long-term reliability due to its superior pulse overload and thermal runaway life. As explained in detail above, the present invention applies to zinc oxide.
Bi ₂ O ₃ , Co ₂ O ₃ , MnO ₂ , Sb ₂ O ₃ , Cr ₂ O ₃ , NiO,
When SiO ₂ , Al ₂ O ₃ or Ga ₂ O ₃ , B ₂ O ₃ , MgO are present at the same time, or when Bi ₂ O ₃ ,
Co ₂ O ₃ , MnO ₂ , Sb ₂ O ₃ , Cr ₂ O ₃ , NiO, SiO ₂ ,
It can only be obtained when Al ₂ O ₃ or Ga ₂ O ₃ , B ₂ O ₃ , MgO, and Ag ₂ O are present at the same time.
This makes it possible to provide a voltage nonlinear resistance element that is excellent in α, V _100A /V _1nA , surge resistance, and pulse-heavy thermal runaway life. Moreover, the above characteristics can be further improved by adding boron or boron and silver in vitrification when adding the above additives. Therefore, by using the voltage nonlinear resistance element according to the present invention, the safety and reliability of equipment and equipment can be improved with a simple configuration.

[Brief explanation of the drawing]

The drawing is a longitudinal sectional view showing an embodiment of a lightning arrester using the voltage nonlinear resistance element of the present invention. 1... Voltage nonlinear resistance element, 2a, 2b... Electrode.

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Claims (1)

[Claims] 1 Bi ₂ O ₃ 0.1 to 3.0 mol %, Co ₂ O ₃ 0.1 to 3.0 mol %, MnO _{2 0.1} to 3.0 mol %, Sb ₂ O _{3 0.1} to 3.0 mol %
Mol%, _Cr2O3 from 0.05 to _1.5 mol%, NiO from 0.1 to
3.0 mol% SiO _, 0.1-10.0 mol%, _Al2O3 or
_Ga2O3 0.0005-0.025 _mol %, _{B2O3 0.005-0.3}
Voltage nonlinear resistance element consisting of a sintered body mainly composed of ZnO containing 0.1 to 25.0 mol% of MgO as an additive. 2 _{0.1-3.0 mol} % _Bi2O3 , 0.1-3.0 mol% _Co2O3 , 0.1-3.0 mol% _MnO2 , _0.1-3.0 mol _{% Sb2O3}
Mol%, _Cr2O3 from 0.05 to _1.5 mol%, NiO from 0.1 to
3.0 mol%, _SiO2 0.1-10.0 mol%, _{Al2O3 or Ga2O3 0.0005-0.025} mol%, _{B2O3 0.005-0.005 mol} %
0.3 mol%, MgO 0.1-25.0 mol%, _Ag2O
A voltage nonlinear resistance element consisting of a sintered body whose main component is ZnO, which contains 0.0005 to 0.3 mol% of additives. 3 Bismuth compounds in an amount of 0.1 to 3.0 mol % in the form of Bi ₂ O ₃ , cobalt compounds in an amount of 0.1 to 3.0 mol % in the form of Co ₂ O ₃ , 0.1 to 3.0 mol % in the form of MnO ₂
3.0 mol% manganese compounds, 0.1-3.0 mol% antimony compounds in the form _{of Sb2O3} , 0.05-1.5 mol% chromium compounds in the form _{of Cr2O3} ,
0.1-3.0 _mol % nickel compounds in the _form of NiO, 0.1-10.0 mol% silicon compounds in the form of _SiO2 , _Al2O3 or _Ga2O3
0.0005 to 0.025 mol% aluminum or gallium compounds, calculated in the form of B ₂ O ₃ from 0.005
0.3 mol% boron compound, calculated in the form of MgO
A voltage characterized in that when adding and mixing 0.1 to 25.0 mol% of a magnesium compound to zinc oxide powder, all of the boron and at least a part of the silicon are vitrified and mixed, and this mixture is shaped and then fired. A method for manufacturing a nonlinear resistance element. 4 5-30% by weight _{of B2O3} , 70-95% by weight of _SiO2
4. A method for manufacturing a voltage nonlinear resistance element according to claim 3, characterized in that all of the boron and part of the silicon are added in the form of borosilicate glass powder having a composition of: 5 All boron and bismuth and silicon in the form of bismuth borosilicate glass powder with a composition of 40-90% by weight Bi ₂ O ₃ , 5-30% by weight B ₂ O ₃ and 5-30% by weight SiO ₂ 4. The method of manufacturing a voltage nonlinear resistance element according to claim 3, wherein a part of the voltage nonlinear resistance element is added. 6 40-85% by weight of _Bi2O3 , 5-25% by weight _{of B2O3} , 5-25% _by weight of _{SiO2 ,} 2-10% by weight of _Co2O3
Voltage nonlinear resistance according to claim 3, characterized in that all of the boron and some of the bismuth, cobalt and silicon are added in the form of a cobalt-doped bismuth borosilicate glass powder of the composition Method of manufacturing elements. 7 All of the boron _and some of the silicon and zinc are added in the form of zinc borosilicate glass powder with a composition of 20-60% by weight of ZnO, 5-30% by weight of _B2O3 and 10-60% by weight of SiO. The method for manufacturing a voltage nonlinear resistance element according to claim 3, characterized in that the voltage nonlinear resistance element is added. 8 Adding all of the boron and some of the silicon in the form of lead borosilicate glass powder with a composition of 10-70% by weight of _PbO , 5-30% by weight of _B2O3 and 10-60% by weight of _SiO2 . A method of manufacturing a voltage nonlinear resistance element according to claim 3, characterized in that: 9 Bismuth compounds in an amount of 0.1 to 3.0 mol % in the form of Bi ₂ O ₃ , cobalt compounds in an amount of 0.1 to 3.0 mol % in the form of Co ₂ O ₃ , 0.1 to 3.0 mol % in the form of MnO ₂
3.0 mol% manganese compounds, 0.1-3.0 mol% antimony compounds in the form _{of Sb2O3} , 0.05-1.5 mol% chromium compounds in the form _{of Cr2O3} ,
0.1-3.0 _mol % nickel compounds in the _form of NiO, 0.1-10.0 mol% silicon compounds in the form of _SiO2 , _Al2O3 or _Ga2O3
0.0005 to 0.025 mol% aluminum or gallium compounds, calculated in the form of B ₂ O ₃ from 0.005
0.3 mol% boron compound, calculated in the form of Ag ₂ O
When adding and mixing 0.0005 to 0.3 mol% of a silver compound and 0.1 to 25.0 mol% of a magnesium compound in the form of MgO to zinc oxide powder, all of the boron and silver and at least a part of the silicon are vitrified. 1. A method for manufacturing a voltage nonlinear resistance element, comprising: adding and mixing the mixture, molding the mixture, and then firing the mixture. 10 _Total amount of boron and silver in the form of silver-doped borosilicate glass powder with a composition of 5-30% by weight of _B2O3 , 45-90% by weight of _SiO2 and 3-25% by weight of _Ag2O . 10. The method of manufacturing a voltage nonlinear resistance element according to claim 9, wherein a part of silicon is added. 11 Bi ₂ O ₃ 45-85% by weight, B ₂ O ₃ 5-25% by weight, SiO ₂ 5-25% by weight, Ag ₂ O 3-25% by weight
Voltage non-linear resistance according to claim 9, characterized in that all of the boron and silver and part of the bismuth and silicon are added in the form of a silver-doped bismuth borosilicate glass powder with a composition of Method of manufacturing elements. 12 _Bi2O3 45-85% _by weight, _B2O3 5-25% by weight, _SiO2 5-25% _by weight, _Co2O3 2-10% _by weight, _Ag2O 3-25% by weight Claim 9, characterized in that all of the boron and silver and part of the bismuth, cobalt and silicon are added in the form of bismuth borosilicate glass powder doped with cobalt and silver in the composition of % by weight. A method of manufacturing the voltage nonlinear resistance element described above. 13 ZnO 20-60% by weight, _B2O3 5-30% by weight, _SiO2 10-60 _% by weight, _Ag2O 3-25% by weight
Claim 9, characterized in that all of the boron and silver and part of the silicon and zinc are added in the form of a silver-doped zinc borosilicate glass powder with a composition of
A method for manufacturing a voltage nonlinear resistance element as described in . 14 10-70% by weight of PbO, 5-30% by weight _{of B2O3} , 10-60% by weight of _SiO2 , 3-25% by weight of _Ag2O
The voltage non-linear resistance element according to claim 9, characterized in that all of the boron and silver and part of the silicon are added in the form of a silver-doped lead borosilicate glass powder having a composition of Production method.