JP2008172034A - Current/voltage nonlinear resistor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a voltage nonlinear resistor which can have an excellent current/voltage nonlinear characteristic, a life characteristic and surge energy resistance, can improve thermal stability at high temperatures, and can contribute to the miniaturization of an overvoltage protection device. <P>SOLUTION: A sintered compact 1 contains ZnO not smaller than 95 mol% as its main component. The compact also contains, as its sub components, 0.3-1 mol% of Bi<SB>2</SB>O<SB>3</SB>, 0.5-2.5 mol% of Sb<SB>2</SB>O<SB>3</SB>, 0.3-1.5 mol% of Co<SB>2</SB>O<SB>3</SB>, 0.2-2 mol% of MnO, and 0.5-3 mol% of NiO when Bi, Sb, Co, Mn and Ni are converted to Bi<SB>2</SB>O<SB>3</SB>, Sb<SB>2</SB>O<SB>3</SB>, Co<SB>2</SB>O<SB>3</SB>, MnO and NiO, respectively. A ratio of NiO to MnO is 2.0 to 6.0, and a ratio of Sb<SB>2</SB>O<SB>3</SB>to MnO is 1.5 to 4.0. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a current-voltage nonlinear resistor mainly composed of zinc oxide (ZnO) applied to an overvoltage protection device, and more particularly to a current-voltage nonlinear resistor excellent in thermal stability at high temperatures. Is.

  In general, overvoltage protection devices such as lightning arresters and surge absorbers are used in power systems and electronic equipment circuits to protect them from abnormal voltages. The overvoltage protection device is provided with a current-voltage nonlinear resistor. The current-voltage nonlinear resistor has a non-linear resistance characteristic that exhibits a low resistance characteristic when an abnormal voltage is applied, while exhibiting almost an insulation characteristic under a normal voltage, and is effective in suppressing overvoltage. .

  The configuration of the current-voltage nonlinear resistor will be described with reference to FIG. The current-voltage non-linear resistor comprises a sintered body 1, and a side high resistance layer 2 is formed on the side surface of the sintered body 1. In addition, electrodes 3 are provided on both flat surfaces of the sintered body 1. Next, a specific manufacturing process of the current-voltage nonlinear resistor will be described.

Here, a current-voltage nonlinear resistor is produced according to the procedure described in Patent Document 1. First, zinc oxide (ZnO) is a main component, and Bi ₂ O ₃ , Sb ₂ O ₃ , Co ₂ O ₃ , MnO and NiO are added in predetermined amounts as subcomponents, and this is used as a raw material. This raw material is sufficiently mixed with water and a binder, and then granulated by a spray dryer or the like and molded.

  Then, in order to remove the added binder beforehand, it heat-processes in air at 400-500 degreeC, and also the sintered body 1 is obtained by baking at 1200 degreeC. Thereafter, an insulating material that prevents creeping flashing is applied to the side surface of the sintered body 1, and heat treatment is performed to form the side high resistance layer 2. After the side high resistance layer 2 is formed, both end surfaces of the sintered body 1 are polished, and an electrode 3 is attached to the polished surface to produce a current-voltage nonlinear resistor.

  By the way, in recent years, the demand for power transmission costs has become stricter, and in order to reduce the power transmission costs, downsizing of transmission and transformation facilities is strongly desired. For this reason, downsizing of the overvoltage protection device that determines the insulation level of the substation equipment is urgently needed. The current-voltage non-linear resistor used in the overvoltage protection device is the protection level itself of the overvoltage protection device, and is an extremely important technical element that influences the miniaturization of the overvoltage protection device and the downsizing of the transmission and substation equipment. ing. Accordingly, various current-voltage nonlinear resistors have been proposed in which various improvements have been made, such as by limiting the constituent components.

  Specifically, Patent Document 2 is a technique for increasing the resistance of a non-linear resistor by limiting the components of the non-linear resistor and limiting the proportion of spinel particles in the sintered body. is there. Further, in the non-linear resistor described in Patent Document 3, the constituent components are limited, and the proportion of the bismuth crystal phase and the ratio in the sintered body is limited, thereby achieving high resistance. According to these techniques, since the number of sheets used in the overvoltage protection device can be reduced by increasing the resistance of the non-linear resistor, it is possible to reduce the size of the overvoltage protection device.

  In addition, a technique for miniaturizing an overvoltage protection device such as a lightning arrester without reducing the discharge withstand capability by forming a non-linear resistor joined unit has been proposed (for example, Patent Document 4). In this technique, a sintered body with improved element strength of a non-linear resistor is obtained by further limiting the formation components and reducing the porosity. If the element strength is increased, the discharge withstand characteristics are improved, so that the nonlinear resistor itself can be miniaturized. For example, Patent Literature 5 discloses a technique for obtaining an excellent discharge tolerance. Here, by limiting the components of the non-linear resistor and reducing the resistance of the non-linear resistor, the discharge withstand characteristics are improved, and the size of the non-linear resistor is reduced.

Japanese Patent Publication No. 4-25681 JP 2002-217006 A JP 2001-307909 A JP 2001-28303 A JP 2001-93705 A

  However, the following problems have been pointed out in the above prior art. In other words, in order to reduce the size of an overvoltage protection device such as a lightning arrester, the current-voltage nonlinear resistor is increased in resistance as in Patent Documents 1 and 2, or the discharge withstand characteristics are improved as in Patent Documents 3 and 4. When proceeding, high surge energy must be handled. As a result, the heat generation temperature increases due to Joule heat generation after absorbing the surge energy. Since the resistance value of current-voltage nonlinear resistors decreases with increasing temperature, if the degree of decrease in resistance value increases, even if surge energy can be processed, leakage current increases and surge energy absorption Later, thermal runaway due to commercial frequency current occurred, and there was a risk that the life characteristics would be degraded.

  For this reason, the size of the current-voltage nonlinear resistor itself is limited in order to absorb the surge energy and suppress the occurrence of thermal runaway. In addition, if the resistance value per current-voltage non-linear resistor is not sufficient, there is no other way than stacking a large number of current-voltage non-linear resistors on an overvoltage protection device such as a lightning arrester. Was inviting.

  The present invention has been made in order to solve the above-described conventional problems, and is excellent in current-voltage nonlinear characteristics, life characteristics, and surge energy withstanding progress in downsizing, and current-voltage nonlinear resistance. Current-voltage nonlinear resistance that can contribute to miniaturization of overvoltage protection devices by reducing the degree of decrease in resistance when the body temperature rises, that is, by improving thermal stability at high temperatures The purpose is to provide a body.

In order to achieve the above object, the present invention defines the types and contents of the constituents of the sintered body as follows. That is, in a current-voltage non-linear resistor composed of a sintered body mainly composed of ZnO, Bi, Sb, Co, Mn, and Ni are added as secondary components to Bi ₂ O ₃ , Sb ₂ O ₃ , and Co ₂ O, respectively. ₃ , converted to MnO and NiO, Bi ₂ O ₃ is 0.3 to 1 mol%, Sb ₂ O ₃ is 0.5 to 2.5 mol%, Co ₂ O ₃ is 0.3 to 1.5 mol%, MnO and 0.2 to 2 mol%, NiO hints 0.5 to 3 mol%, the content ratio of the NiO to said MnO is 2.0 to 6.0, a content of the _Sb 2 _{O 3} relative to the MnO It consists of a sintered body having a ratio of 1.5 to 4.0.

In the present invention as described above, Bi ₂ O ₃ is a component that exists in the grain boundary of ZnO as a main component and develops non-linear resistance characteristics, and Sb ₂ O ₃ forms spinel particles with ZnO. It is a component which has the effect | action which suppresses the grain growth of the ZnO particle | grain during sintering, and has the effect | action which makes uniform and improves a non-linear resistance characteristic. Further, Co ₂ O ₃ , MnO and NiO are effective components mainly for solid solution in spinel particles and greatly improving the non-linear resistance characteristics. In the current-voltage non-linear resistor according to the present invention, the subcomponent is defined in the above range, and the ratio of the content of NiO to MnO is set to 2.0 to 6.0, and Sb ₂ to MnO is set. By setting the ratio of the content of O ₃ to 1.5 to 4.0, the degree of decrease in the resistance value when the temperature of the current-voltage nonlinear resistor is increased can be reduced. In addition, excellent non-linear resistance characteristics can be ensured.

According to the current-voltage non-linear resistor of the present invention, the content of Bi, Sb, Co, Mn, and Ni, which are subcomponents of the sintered body, is specified in the range, and the ratio of NiO to MnO and to MnO By defining the ratio of Sb ₂ O ₃ , it has excellent current-voltage non-linear characteristics, life characteristics and surge energy withstand capability, and it is possible to improve thermal stability at high temperatures, and downsizing of overvoltage protection devices Can contribute.

  Hereinafter, an example of an embodiment according to the present invention will be specifically described with reference to the drawings. As described above, the voltage non-linear resistor is made of the sintered body 1, the side high resistance layer 2 is formed on the side surface portion, and the electrodes 3 are provided on both flat surfaces of the sintered body 1 (see FIG. 1). All the embodiments described below relate to the constituent components of the sintered body 1.

(1) First Embodiment [Manufacturing Process of Current-Voltage Nonlinear Resistor]
First, a sample corresponding to the first embodiment and a sample outside the scope of the present invention, which is a comparative example, are manufactured according to the following procedure.

First, Bi ₂ O ₃ and Sb ₂ as subcomponents with respect to ZnO as the main component so that the subcomponent contents of the current-voltage nonlinear resistor finally obtained have values shown in Table 1 below. A predetermined amount of O ₃ , Co ₂ O ₃ , MnO and NiO is weighed. And this raw material is mixed with a mixing apparatus with water and organic binders, and uniform slurry is adjusted. In all the slurries prepared here, aluminum is made into an aluminum hydroxide (Al ₂ O ₃ ) aqueous solution, and 0.008 mol% is added. Next, each obtained slurry is spray-granulated with a spray dryer to produce granulated powder having a particle size of about 100 μm.

The obtained granulated powder is put into a mold and pressurized, formed into a cylinder having a diameter of 48 mm and a thickness of 38 mm, and the molded body is heated to 500 ° C. to remove the added organic binders. By changing the atmosphere and temperature conditions during firing, firing is performed so that the voltage (operation start voltage, V _{1 mA} ) when a current of 1 mA flows is about 200 V / mm. Subsequently, as shown in FIG. 1, an inorganic insulating material is applied to the side surface of the sintered body 1 and heat-treated to form the side surface insulating layer 2. Furthermore, after polishing both the upper and lower end surfaces of the sintered body provided with the side insulating layer, the electrode 3 was prepared on the polished surface of the sintered body 1 by thermal spraying to produce a current-voltage nonlinear resistor.

[Performance evaluation]
The non-linear resistance characteristics of the various current-voltage non-linear resistors manufactured are evaluated as follows. That is, a voltage when an electric current of 1 mA flows (operation start voltage, V _{1 mA} ) and a voltage when an 8 × 20 μs impulse current of _{10 kA} flows (V _{10 kA} ) are measured, and a ratio thereof (V _{10 kA} / V _{1 mA).} ) Was evaluated as a nonlinear coefficient. The smaller the value of this nonlinearity coefficient, the better the nonlinear resistance characteristic.

In addition, the produced current-voltage nonlinear resistor was heated to 200 ° C. in a thermostatic chamber, and the resistance leakage current (IR) was measured when an AC voltage of 90% of the operation start voltage (V _{1 mA} ) was applied. ,evaluated. This resistance leakage current indicates that the smaller the value, the better the thermal stability at high temperatures. Each composition sample was measured for each 10p, and the average value was defined as the non-linearity coefficient of the composition and the resistance leakage current at 200 ° C.

  Table 1 below shows the content of each component, the operation start voltage, the nonlinearity coefficient, and the resistance leakage current at 200 ° C. for the current-voltage nonlinear resistors manufactured by changing the amount of each additive component. In Table 1, * marks are comparative examples showing samples that are outside the scope of the present invention.

Here, the current-voltage nonlinear resistor corresponding to the first embodiment has the following components (samples not marked with * in Table 1). That is, the sintered body 1 containing ZnO as a main component converts Bi, Sb, Co, Mn, and Ni as subcomponents into Bi ₂ O ₃ , Sb ₂ O ₃ , Co ₂ O ₃ , MnO, and NiO, respectively. Bi ₂ O ₃ 0.3-1 mol%, Sb ₂ O ₃ 0.5-2.5 mol%, Co ₂ O ₃ 0.3-1.5 mol%, MnO 0.2-2 mol% NiO is contained in an amount of 0.5 to 3 mol%. Moreover, the ratio of the content of NiO to MnO is 2.0 to 6.0, and the ratio of the content of Sb ₂ O _{3 to} MnO is 1.5 to 4.0. Furthermore, the content of ZnO which is the main component of the sintered body 1 is 95 mol% or more.

Of the comparative examples marked with *, points that do not correspond to this embodiment are the following parts. Sample Nos. 1, 7, 12, 18, 19, 24, 34, 39, 40, 43, 45, 47, and 49 have a NiO to MnO ratio of less than 2.0 or greater than 6.0. is there. Moreover, both the sample No. 25,30,31,32,38,40～47,49, the ratio of the content of _Sb 2 _{O 3} with respect to MnO is less than 1.5. Further, in sample numbers 37 to 52, the content of ZnO as the main component of the sintered body 1 is less than 95 mol%.

[Function and effect]
Then, the effect of 1st Embodiment is demonstrated by comparing the sample applicable to this embodiment with the other sample. Here, as is clear from the results in Table 1, in the current-voltage nonlinear resistor according to the present embodiment, the nonlinear resistance characteristic (V _{10 kA} / V _{1 mA} ) is 1.74 or less, and the thermal stability (200 The leakage current at ° C.) was an excellent level of less than 3.00 (mA). On the other hand, although the comparative example which is a sample outside the scope of the present invention has an excellent non-linear resistance characteristic or thermal stability, none of them satisfies both characteristics at the same time.

As is clear from this, in the first embodiment, 95 mol% or more of ZnO is the main component, Bi ₂ O ₃ is 0.3 to 1 mol%, and Sb ₂ O ₃ is 0.5 to 2.5 mol%. Co ₂ O ₃ is contained in an amount of 0.3 to 1.5 mol%, MnO is contained in an amount of 0.2 to 2 mol%, NiO is contained in an amount of 0.5 to ₃ mol%, and the ratio of the content of NiO to MnO is 2.0 to 6.0. By applying the sintered body 1 in which the ratio of the content of Sb2O3 to MnO is 1.5 to 4.0, it was possible to exhibit excellent thermal stability at high temperatures.

  Therefore, it is necessary to process high surge energy by increasing the resistance of the current-voltage nonlinear resistor and improving the discharge withstand characteristics, and even if the heating temperature increases due to Joule heating, the resistance value The degree of decline can be kept low. As a result, there is no fear of an increase in leakage current, and it is possible to prevent the occurrence of thermal runaway due to the commercial frequency current after absorption of surge energy, thereby preventing deterioration of the life characteristics.

  Moreover, since the occurrence of thermal runaway can be suppressed without limiting the size of the current-voltage non-linear resistor itself, the current-voltage non-linear resistor itself can be reduced in size. Current-voltage nonlinear characteristics can be obtained. Therefore, it is possible to reduce the size of the overvoltage protection device such as a lightning arrester and the like and to reduce the size of the transmission / transformation equipment with high reliability, thereby contributing to the reduction of the transmission cost.

(2) Second Embodiment [Configuration]
Next, a second embodiment will be described. In 2nd Embodiment, content of a subcomponent is prescribed | regulated as follows with respect to ZnO as a main component. That is, Bi, Co, and Mn are respectively included in terms of Bi ₂ O ₃ , Co ₂ O ₃ , and MnO in an amount of 1.0 mol%, and Sb and Ni are respectively included in terms of Sb ₂ O ₃ and NiO in an amount of 2 mol%. Al ₂ O ₃ was weighed so as to be 0.008 mol% in terms of Al ³⁺ and added.

In the second embodiment, B is added so as to contain 0.005 to 0.05 wt% in terms of B ₂ O ₃ with respect to the basic composition, and the method shown in the first embodiment is used. A current-voltage nonlinear resistor was produced. Table 2 shows the content of B ₂ O _{3 and} the rate of change in leakage current. The sample numbers marked with * shown in Table 2 are comparative examples that are outside the scope of the present invention.

[Performance evaluation]
In the second embodiment, the life characteristics of various current-voltage nonlinear resistors manufactured as described above were evaluated as follows. That is, in the life characteristic evaluation, the operation start voltage (V _{1 mA} ) was continuously applied in the atmosphere at 120 ° C. for 3000 h, and the rate of change in leakage current (IR) was measured when V _{1 mA} before and after that was applied. Here, the rate of change can be expressed by the equation IR (after 3000 h) / IR (initial value, 0 h). If this value is smaller than 1, the life characteristics of the current-voltage nonlinear resistor are excellent. Is shown.

[Function and effect]
As is clear from Table 2, in the second embodiment, by defining the content of B ₂ O ₃ to 0.005 to 0.05 wt%, the rate of change in leakage current becomes a negative value, and the nonlinearity It has been found that a current-voltage non-linear resistor having excellent life characteristics can be obtained while miniaturizing the resistor itself. In the present embodiment, only the basic composition showed the effect of improving the life characteristics due to the addition of B, but it has been confirmed that the same effect can be obtained in the basic composition range of claims 1 and 2. It is.

(3) Third Embodiment [Configuration]
In 3rd Embodiment, content of a subcomponent is prescribed | regulated as follows with respect to ZnO as a main component. That is, Bi, Co, and Mn are respectively included in terms of Bi ₂ O ₃ , Co ₂ O ₃ , and MnO in an amount of 1.0 mol%, and Sb and Ni are respectively included in terms of Sb ₂ O ₃ and NiO in an amount of 2 mol%. Al ₂ O ₃ was weighed so as to be 0.008 mol% in terms of Al ³⁺ and added.

In the third embodiment, Ag is added to the basic composition so as to contain 0.005 to 0.05 wt% in terms of Ag ₂ O, and the current is applied by the method shown in the first embodiment. -A voltage non-linear resistor was produced. Table 3 shows the content of Ag ₂ O and the rate of change in leakage current. In addition, the sample number attached | subjected * shown in Table 3 is a comparative example which is outside the scope of the present invention.

[Performance evaluation]
In the third embodiment as described above, the life characteristics are evaluated by the same method as the method shown in the second embodiment.

[Function and effect]
As is apparent from Table 3, in the third embodiment, by defining the content of Ag ₂ O to 0.005 to 0.05 wt%, the rate of change in leakage current becomes a negative value, and the second As in the embodiment, the current-voltage nonlinear resistor having excellent life characteristics was obtained while the size of the nonlinear resistor itself was reduced. In the present embodiment, only the basic composition showed the effect of adding to the life characteristics of Ag. However, it has been confirmed that the same effect can be obtained if the basic composition range is defined in claims 1 and 2. is there.

(4) Fourth Embodiment [Configuration]
In the fourth embodiment, the content of subcomponents is defined as follows with respect to ZnO as a main component. That is, Bi, Co, and Mn are respectively included in terms of Bi ₂ O ₃ , Co ₂ O ₃ , and MnO in an amount of 1.0 mol%, and Sb and Ni are respectively included in terms of Sb ₂ O ₃ and NiO in an amount of 2 mol%. B and Ag were weighed and added to 0.02 wt% in terms of B ₂ O ₃ and Ag ₂ O, respectively.

Further, in the fourth embodiment, Al ₂ O ₃ is added to the basic composition so as to contain 0.001 to 0.01 mol% in terms of Al ³⁺ and shown in the first embodiment. A current-voltage nonlinear resistor was produced by this method. Table 4 shows the content of Al ³⁺ and nonlinear resistance characteristics. Note that the sample numbers marked with * shown in Table 4 are comparative examples that are outside the scope of the present invention.

[Performance evaluation]
The non-linear resistor characteristics in the fourth embodiment were evaluated by the same method as the method shown in the first embodiment.

[Function and effect]
According to the fourth embodiment, as shown in Table 4, if the content of Al ³⁺ is in the range of 0.001 to 0.01 mol%, the nonlinear resistor itself can be downsized, It has been found that excellent non-linear resistance characteristics can be obtained. In the present embodiment, only the basic composition has an additive content effect on the life characteristics of Al. However, it has been confirmed that the same effect can be obtained within the basic composition range of claim 1. In addition, it has been confirmed that the same effect of Al can be obtained for a composition containing ZnO, B, and Ag in the range of the claims 2 to 4 in the composition in the range of the claim 1.

(5) Fifth Embodiment [Configuration]
The fifth embodiment will be described with reference to Table 5. In the fifth embodiment, the content of subcomponents is defined as follows with respect to ZnO as the main component, as in the third embodiment. That is, Bi and Co are respectively converted to Bi ₂ O ₃ and Co ₂ O ₃ to contain 1.0 mol%, Ni is converted to NiO and 2 mol% is included, and Ag is converted to Ag ₂ O and 0.02 wt%. In addition, Al ₂ O ₃ was weighed so as to be 0.008 mol% in terms of Al ³⁺ and added.

  Further, in the fifth embodiment, the current-voltage nonlinear resistor is manufactured by the method shown in the first embodiment, but the feature is that the temperature-decreasing rate at the time of firing is set to 50 ° C./h or more. is there. Table 5 shows the leakage current at high temperature in a current-voltage nonlinear resistor manufactured by changing the temperature drop rate during firing to 25 to 100 ° C./h. In Table 5, * indicates a sample that is outside the scope of the present invention.

[Performance evaluation]
In the fifth embodiment, the leakage current at high temperature was evaluated by the same method as the method shown in the first embodiment. That is, the produced current-voltage nonlinear resistor was heated to 200 ° C. in a thermostatic chamber, and the resistance leakage current (IR) was measured when an AC voltage of 90% of the operation start voltage (V _{1 mA} ) was applied. ,evaluated.

[Function and effect]
As is apparent from Table 5, the current-voltage nonlinear resistor according to the fifth embodiment has an excellent level of thermal stability (leakage current at 200 ° C.) of 5.30 (mA) or less. On the other hand, the comparative example (sample number 75), which is a sample outside the scope of the present invention, had a low thermal stability of 7.83 (mA). Thus, according to the fifth embodiment, by setting the temperature drop rate during firing to 50 ° C./h or more, the leakage current at high temperature is reduced, and the current-voltage nonlinear resistance excellent in thermal stability. It turned out that a body was obtained.

  In other words, even if the heat generation temperature increases due to Joule heat generation, the degree of decrease in resistance value can be kept low, and the occurrence of thermal runaway due to commercial frequency current after surge energy absorption is reliably prevented, improving the life characteristics. Can be made. In addition, since it is not necessary to increase the current-voltage nonlinear resistor itself to prevent thermal runaway, it is possible to improve the current-voltage nonlinear characteristics while efficiently reducing the size of the current-voltage nonlinear resistor itself. It becomes. In this embodiment, only the basic composition has an effect on the thermal stability of the temperature drop rate during firing. However, the composition in the range of claim 1 has a ZnO content in the range of claims 2 to 5. It has also been confirmed that the same effect can be obtained with a composition containing B, Ag, Al.

(6) Sixth Embodiment [Configuration]
The sixth embodiment will be described with reference to Table 6. In the sixth embodiment, the content of subcomponents is defined as follows with respect to ZnO as a main component. That is, Bi, Co, and Mn are respectively included in terms of Bi ₂ O ₃ , Co ₂ O ₃ , and MnO in an amount of 1.0 mol%, Sb and Ni are converted in terms of Sb ₂ O ₃ and NiO, respectively, and 2 mol% are included. In addition, 0.02 wt% was converted to B ₂ O ₃ and Ag ₂ O, respectively, and Al ₂ O ₃ was measured to be 0.008 mol% converted to Al ³⁺ and added.

Further, in the sixth embodiment, Zr and Fe are added to the basic composition so as to contain 0.1 to 1000 ppm in terms of ZrO ₂ and Fe ₂ O _3, and are shown in the first embodiment. A current-voltage nonlinear resistor was produced by this method. Table 6 shows the measurement results of the energy withstand value and the nonlinearity coefficient for each current-voltage nonlinear resistor. In Table 6, * marks are comparative examples showing samples that are outside the scope of the present invention.

[Performance evaluation]
In the sixth embodiment, the energy tolerance test was performed on various current-voltage nonlinear resistors manufactured as described above. In the energy tolerance test, a voltage of 1.3 times the commercial frequency (50 Hz) is continuously applied to the voltage (V _{1 mA} ) when a 1 mA alternating current is passed through the current-voltage nonlinear resistor, and the AE detector Was used to measure the energy value (J / cc) absorbed until a crack generated in the current-voltage nonlinear resistor was detected. In such an energy withstand test, the current-voltage nonlinear resistor 10p of each composition was tested, and the average value was defined as the energy withstand value of the composition. Further, for these produced current-voltage nonlinear resistors, the nonlinear coefficient was measured by the method shown in the first embodiment, and the nonlinear resistance characteristics were also evaluated.

[Function and effect]
As shown in Table 6, among the comparative examples in the sixth embodiment, in the sample numbers 79 and 90 in which the content of ZrO ₂ or Fe ₂ O ₃ was less than 0.1 ppm, the energy tolerance was low. In Sample Nos. 89 and 100 having a ZrO ₂ or Fe ₂ O ₃ content of more than 1000 ppm, the nonlinear coefficient was high.

On the other hand, in the current-voltage nonlinear resistor according to the sixth embodiment, excellent nonlinear resistance characteristics can be obtained by defining the content of ZrO ₂ or Fe ₂ O ₃ in the range of 0.1 to 1000 ppm. It can be seen that the energy tolerance can be improved while maintaining the above.

  In the present embodiment, the effect of containing Zr or Fe was shown only for the basic composition, but it has been confirmed that the same effect can be obtained within the basic composition range of claim 1. In addition, it has been confirmed that the same effect of Zr or Fe can be obtained for a composition containing ZnO, B, Ag, and Al in the range of claims 2 to 5 in the composition in the range of claim 1. is there. Furthermore, in this embodiment, although the effect when Zr and Fe were each contained independently was shown, it has also been confirmed that the same effect can be obtained even if these are added simultaneously.

(7) Other Embodiments The present invention is not limited to the above-described embodiments, and the content of each constituent component can be changed as appropriate within the range described in each claim. Combinations of forms can also be selected as appropriate.

Sectional drawing of a voltage non-linear resistor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Sintered body 2 ... Side high resistance layer 3 ... Electrode

Claims (8)

In a current-voltage nonlinear resistor composed of a sintered body mainly composed of ZnO,
Bi, Sb, Co, Mn, Ni as subcomponents are converted into Bi ₂ O ₃ , Sb ₂ O ₃ , Co ₂ O ₃ , MnO and NiO, respectively.
0.3~1mol% of Bi ₂ O _3,
0.5~2.5mol% of Sb ₂ O _3,
0.3～1.5Mol% of Co ₂ O _3,
0.2 to 2 mol% of MnO,
Containing 0.5-3 mol% of NiO,
A ratio of the content of the NiO to the MnO is 2.0 to 6.0,
A current-voltage non-linear resistor comprising a sintered body having a ratio of the Sb ₂ O ₃ content to the MnO of 1.5 to 4.0.   2. The current-voltage nonlinear resistor according to claim 1, wherein the current-voltage nonlinear resistor is made of a sintered body having a content of ZnO as a main component of 95 mol% or more. Current according to claim 1 or 2, characterized in that a sintered body of B as an auxiliary component in terms of _B 2 _{O 3} containing 0.005 to 0.05% - voltage nonlinear resistor. Current according to any one of claims 1 to 3, the Ag as a sub-component, characterized in that a sintered body in terms of Ag ₂ O containing 0.005 to 0.05% - voltage nonlinear resistor body. The current-voltage nonlinear resistor according to any one of claims 1 to 4, wherein the current-voltage non-linear resistor is formed of a sintered body containing 0.001 to 0.01 mol% of Al as a subcomponent in terms of Al3 ^+. .   The current-voltage nonlinear resistor according to any one of claims 1 to 5, wherein the current-voltage nonlinear resistor is made of a sintered body having a temperature drop rate during cooling during firing of 50 ° C / h or more. The current-voltage nonlinear resistor according to claim 1, comprising a sintered body containing 0.1 to 1000 ppm of Zr as a subcomponent in terms of ZrO ₂ . The current-voltage nonlinear resistor according to any one of claims 1 to 6, comprising a sintered body containing 0.1 to 1000 ppm of Fe in terms of Fe ₂ O ₃ as a subcomponent. .

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