JPH09246016A - Nonlinear resistor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonlinear resistor which has such an excellent energy resistance characteristic that can avoid its destruction even when absorbing a large surge energy. SOLUTION: A raw material containing zinc oxide as its main component and added at least with bismuth and antimony is prepared, mixed and powdered. Thereafter the powder is put in molds, compress molded and heated in the air, e.g. at a temperature of 500 deg.C. The mold is burned, e.g. at 120 deg.C to obtain a sintered member 1. In a burning step, such conditions as shape and dimensions of a burning sheath and burning atmosphere are selected or controlled to control distribution in bismuth amount, bismuth vapor amount, bismuth oxide crystalline phase, zinc and antimony amounts in the bismuth oxide crystal in the sintered member in respective limit ranges The sintered member 1 is coated on its side with insulating material and baked at a predetermined temperature to form a high resistance layer 2. End faces of both sides of the sintered member 1 are polished and flame-sprayed with aluminum to form electrodes 3.

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 a lightning arrester, a surge absorber, etc., and more particularly to a sintered body formed by firing a raw material containing zinc oxide as a main component.

[0002]

2. Description of the Related Art Generally, in a power system, an overvoltage protection device such as a lightning arrester or a surge absorber is used to remove an overvoltage superimposed on a normal voltage and protect the power system and electric equipment. In many cases, in this overvoltage protection device, a non-linear resistor is used which has a characteristic of exhibiting a substantially insulating characteristic at a normal voltage and a low resistance value when an overvoltage is applied.

Such a non-linear resistor, as shown in FIG. 1, is a disc-shaped sintered body 1 formed by firing a raw material containing zinc oxide as a main component, and a sintered body 1 of this type. The high resistance layer 2 is formed on the side surface, and the electrodes 3 are formed on both end surfaces of the sintered body 1. Here, the sintered body 1 has zinc oxide as a main component, and at least one or more kinds of metals as additives are added as a raw material in order to obtain non-linear characteristics, and the raw material is mixed, granulated, and molded. It is formed by firing later. In this case, as the metal additive, for example, manganese, chromium, bismuth, antimony, nickel or the like is used. In addition, silicon is added as a non-metal additive. The high resistance layer 2 is formed by baking a coated insulating material, and the electrode 3 is formed by polishing the end faces on both sides of the sintered body 1 and then spraying aluminum on the end faces. The non-linear resistor having such a configuration is
A plurality of required numbers are laminated according to the system voltage, and in this laminated state, they are used for lightning arresters and surge absorbers.

[0004]

By the way, in recent years, the capacity and the voltage of the electric power system have been increased, and accordingly, a surge arrester for a high voltage capable of processing a large surge energy has been required. However, the conventional non-linear resistor having the above-mentioned configuration generates heat when a large surge energy is absorbed, and may be destroyed due to the generated thermal stress or partial current concentration. It's a problem.

The present invention has been proposed in order to solve the problems of the prior art as described above, and an object thereof is to provide an excellent energy tolerance without destroying even when a large surge energy is absorbed. It is to provide a non-linear resistor having characteristics.

[0006]

In order to achieve the above-mentioned objects, the present invention contains zinc oxide (ZnO) as a main component and at least bismuth (Bi) and antimony (Sb) as additives. In the non-linear resistor using the added sintered body, the distribution of the amount of bismuth in the sintered body (the ratio of the concentration of bismuth in the vicinity of the surface to the center: B2 / B1), the amount of bismuth evaporation (the central portion with respect to the amount of added bismuth) And the bismuth amount concentration ratio near the surface: B1 / B, B2 / B), the bismuth oxide crystal phase, the zinc amount and the antimony amount in the bismuth oxide crystal are controlled, and these are appropriately controlled within the respective limited ranges. As a result, it is possible to improve energy withstand characteristics when a large surge energy is absorbed. Appropriate control for each controlled object of the sintered body as described above can be easily realized by appropriately selecting or controlling conditions such as firing temperature pattern, firing sheath shape, dimensions and firing atmosphere during the firing process. It is possible.

According to the first aspect of the present invention, the distribution of the bismuth amount in the sintered body is controlled. The bismuth amount concentration in the central portion of the sintered body is B1 (wt%), and the bismuth amount concentration near the surface is And B2 (wt%), the ratio B2 /
It is characterized in that B1 is in the range of 0.6 <(B2 / B1) <1.

According to the first aspect of the present invention having the above-mentioned structure, the bismuth amount is controlled so that the bismuth amount concentration ratio B2 / B1 in the vicinity of the surface to the central portion of the sintered body is maintained at a sufficient level. By controlling the distribution, it is possible to suppress an increase in electric resistance in the vicinity of the surface of the sintered body, and it is possible to improve energy withstand characteristics of the nonlinear resistor.

According to the first aspect of the present invention, the inventors of the present invention have made intensive studies on the relationship between various metal additives and the energy withstand characteristics of the non-linear resistor. It was obtained as a result of discovering that it is an influencing factor that has a great influence on the energy withstand characteristic of a linear resistor, and examining the most appropriate condition for this distribution. That is, zinc oxide (ZnO) added with bismuth
In the non-linear resistor, the bismuth oxide, which is an accessory component, is likely to evaporate during firing, and particularly to evaporate near the surface of the sintered body. When the concentration of bismuth in the vicinity of the surface of the sintered body is low, the particle size of the zinc oxide particles in this part becomes small and the number of grain boundaries increases, so that the electrical resistance of this part becomes high. It becomes more difficult for current to flow than in the central portion, which leads to deterioration in energy withstand characteristics of the nonlinear resistor.

Further, the present inventor has found that not only the distribution of the amount of bismuth in the sintered body, but also the amount of bismuth evaporation, the bismuth oxide crystal phase, the amount of zinc and the amount of antimony in the bismuth oxide crystal are non-linear. It has been discovered that it is an influencing factor that has a large effect on the energy withstand characteristics of the resistor.
Each of the inventions described in claims 2 to 6 is obtained as a result of investigating the most suitable condition for each such influencing factor.

According to a second aspect of the present invention, in addition to the first aspect of the present invention, the amount of bismuth vaporized by firing is controlled based on the concentration of bismuth in the center of the bismuth. The amount concentration is B (w
t%), the ratio B1 / B between the added bismuth amount concentration B and the bismuth amount concentration B1 at the center of the sintered body.
Is within the range of 0.7 <(B1 / B).

According to the second aspect of the present invention having the above-described structure, the bismuth evaporation amount is controlled so that the ratio of the central bismuth amount concentration to the added bismuth amount concentration: B1 / B is maintained at a sufficient level. By doing so, the energy withstand characteristic of the non-linear resistor can be further improved.

[0013] The invention according to claim 3 is the invention according to claim 1 or 2.
In the invention described above, the amount of bismuth vaporized by firing is further controlled based on the concentration of bismuth in the vicinity of the surface, and when the concentration of added bismuth with respect to the zinc oxide is B (wt%), The ratio B2 / B between the added bismuth amount concentration B and the bismuth amount concentration B2 in the vicinity of the surface of the sintered body is characterized by being in the range of 0.5 <(B2 / B).

According to the third aspect of the invention having the above-mentioned structure, the bismuth evaporation amount is controlled so that the ratio of the bismuth amount concentration near the surface to the added bismuth amount concentration: B2 / B is maintained at a sufficient level. By doing so, the energy withstand characteristic of the non-linear resistor can be further improved.

The invention according to claim 4 is the invention according to any one of claims 1 to 3, further comprising controlling a bismuth oxide crystal phase formed in the sintered body,
In particular, bismuth oxide (Bi ₂
It is characterized in that the main crystal phase of O ₃ ) is the same crystal phase in the central part of the sintered body and in the vicinity of the surface.

According to the invention having the above-mentioned structure, the main crystal phase of bismuth oxide formed in the sintered body is controlled to be the same in each portion of the sintered body. As a result, the energy withstand characteristic of the non-linear resistor can be further improved.

According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the amount of zinc contained in the bismuth oxide crystal is further controlled. The amount of zinc (Zn) contained in the bismuth oxide (Bi ₂ O ₃ ) crystal formed in 1) is in the range of 2 to 20 mol% both in the center and near the surface of the sintered body. Is characterized by.

According to the invention having the above-mentioned structure, the amount of zinc in the bismuth oxide crystal formed in the sintered body is controlled within a certain range in each part of the sintered body. As a result, the energy withstand characteristic of the non-linear resistor can be further improved.

The invention according to claim 6 is the invention according to any one of claims 1 to 5, which further controls the amount of antimony contained in the bismuth oxide crystal. Bismuth oxide (B) formed in the body
It is characterized in that the amount of antimony (Sb) contained in the i ₂ O ₃ ) crystal is within the range of 0.3 to 10 mol% both in the central portion and near the surface of the sintered body.

According to the invention of claim 6 having the above-mentioned constitution, by controlling the amount of antimony in the bismuth oxide crystal of the sintered body within a certain range in each part of the sintered body, The energy withstand characteristic of the linear resistor can be further improved.

[0021]

EXAMPLES Examples of the non-linear resistor according to the present invention will be specifically described below with reference to FIGS.

[1. Manufacturing Process] First, with respect to zinc oxide (ZnO) as a main component, manganese dioxide (Mn
O ₂ ), silicon dioxide (SiO ₂ ), and chromium oxide (Cr ₂ O ₃ ), for example, 0.5 mol% each, and bismuth oxide (Bi ₂ O ₃ ), antimony oxide (Sb ₂ O ₃ ). ₃ ), nickel oxide (NiO),
For example, 1 mol% each is added.

Next, the raw materials thus prepared are put together with water and an organic binder such as a dispersant in a mixing apparatus (mixing step), and the mixture is spray-granulated by a spray dryer (granulation step). ). This granulated powder is put into a mold and pressed to form a disk having a diameter of 125 mm and a thickness of 30 mm, for example (molding step). Subsequently, in order to remove the added dispersant and binder, the molded body is preheated in air at, for example, 500 ° C. (heat treatment step).

The molded body thus heat-treated is, for example,
Firing at 1200 ° C. forms a sintered body (firing step).
In this firing step, as described above, by selecting or controlling the conditions such as the firing temperature pattern, the shape of the firing sheath, the dimensions, and the firing atmosphere, the six types of control targets according to claims 1 to 6 are respectively controlled. Control properly. That is, the distribution of the bismuth amount in the sintered body (the bismuth amount concentration ratio in the vicinity of the surface to the central portion: B2 / B1), the bismuth evaporation amount (the bismuth amount concentration ratio in the central portion to the added bismuth amount concentration: B1 / B), Evaporation amount of bismuth (ratio of bismuth amount concentration near the surface to added bismuth amount concentration: B
2 / B), the bismuth oxide crystal phase, the amount of zinc in the bismuth oxide crystal, and the amount of antimony in the bismuth oxide crystal are appropriately controlled within the respective limited ranges.

Thereafter, as shown in FIG. 1, an insulator is applied to the side surface of the obtained sintered body 1 (FIG. 1) and baked at a predetermined temperature to form a high resistance layer 2. Next, after polishing the end faces on both sides of the sintered body 1, the electrodes 3 are formed on this surface by thermal spraying of aluminum or the like to complete the nonlinear resistor.

[2. Energy Tolerance Test] Actually, according to the above-described manufacturing process, a large number of non-linear resistors over a wide range were produced for each of the above-mentioned 6 types of controlled objects, and an energy withstand test was performed. That is, with respect to each of the controlled objects ~, the control conditions are changed over a wide range including each limited range and its comparison range according to the present invention, and the other five kinds of controlled objects are controlled in substantially the same manner, When a large number of non-linear resistors were produced and an energy withstand test was conducted by applying an AC voltage of about 5000 V, the results shown in FIGS. 2 to 6 and Table 1 were obtained. In these figures, the energy withstand value indicates the amount of energy in which a crack has occurred or the amount of energy in which dielectric breakdown has occurred.

Test on Distribution of Bismuth Content in Sintered Body (Bismuth Concentration Ratio in the Vicinity of Surface to Center: B2 / B1) ... FIG. 2 FIG. 2 shows bismuth in the center of the sintered body in the non-linear resistor. Ratio B2 / B1 when the amount concentration is B1 (wt%) and the bismuth amount concentration near the surface is B2 (wt%)
3 is a graph showing the relationship between the energy resistance value of the non-linear resistor. That is, FIG. 2 shows that B2 /
The results obtained when a large number of non-linear resistors are manufactured by changing the value of B1 and an energy withstand test is performed by applying an AC voltage of about 5000 V to these non-linear resistors are shown. In this case, the amount of bismuth in the sintered body is measured by cutting out the central portion and the surface vicinity of the sintered body,
After pulverization and acid dissolution, ICP (plasma emission spectroscopy)
Performed by the method.

As is apparent from FIG. 2, B2 / B1
A non-linear resistor having a value of .gtoreq.0.6 exhibits excellent energy withstanding characteristics. In addition, in this example, a non-linear resistor that satisfies (B2 / B1) ≧ 1 was not obtained. In addition, in the present embodiment, such an effect is obtained for the following reason.

That is, in the ZnO-based non-linear resistor to which bismuth is added, the bismuth oxide, which is an accessory component, easily evaporates during firing, and the amount of evaporation tends to vary depending on the position in the sintered body. There is. in this way,
When the amount of bismuth varies depending on the position in the sintered body, the grain growth characteristics of zinc oxide partially differ, and the grain growth becomes easier when the amount of bismuth oxide is large. Here, since the grain growth of zinc oxide particles, that is, the particle size of zinc oxide particles, directly controls the electrical characteristics, the distribution of the amount of bismuth in the sintered body that influences such particle size is This will have a great influence on the distribution of resistance. In particular, since bismuth is likely to evaporate near the surface of the sintered body, the particle size of the zinc oxide particles becomes small and the number of grain boundaries increases in the vicinity of the surface. A current is less likely to flow when energy is absorbed than in the central portion, which leads to the energy withstand characteristics of the nonlinear resistor.

On the other hand, in this embodiment, as shown in FIG.
As is clear from the distribution of the bismuth content in the sintered body,
By controlling the value of B2 / B1 to be larger than 0.6, a non-linear resistor having excellent energy withstand characteristics was obtained.

Test on evaporation amount of bismuth (ratio of bismuth amount concentration at the central portion to added bismuth amount concentration: B1 / B) ... FIG. 3 In FIG. 3, the value of B2 / B1 is 0.6 <(B2 / B1) <
In the non-linear resistor of No. 1, the ratio B1 / B of the added bismuth amount concentration to B (wt%) and the bismuth amount concentration B1 at the center of the sintered body, and the non-linear resistor 3 is a graph showing a relationship with the energy withstand value of the. That is, in FIG. 3, by adjusting the conditions in the firing process as described above, the value of B2 / B1 is controlled to be larger than 0.6 and the value of B1 / B is changed. The results obtained when a large number of non-linear resistors are produced and an energy withstand test is performed by applying an AC voltage of about 5000 V to these non-linear resistors are shown. The amount of bismuth in the sintered body was measured by the ICP method in the same manner as the test method for the distribution of bismuth described above.

As is apparent from FIG. 3, the non-linear resistor having a B1 / B value of more than 0.7 exhibits excellent energy withstanding characteristics. That is, as described above, since bismuth easily evaporates during firing, in this example, the bismuth amount in the central portion of the sintered body should be maintained at a level of 70% or more with respect to the added amount. A non-linear resistor having excellent energy withstand characteristics was obtained by controlling the evaporation amount of.

Test on evaporation amount of bismuth (ratio of concentration of bismuth amount near the surface to added bismuth amount concentration: B2 / B) ... FIG. 4 In FIG. 4, the value of B2 / B1 is 0.6 <(B2 / B1) <
In the non-linear resistor of No. 1, when the added bismuth amount concentration is B (wt%), a ratio B2 / B between this B and the bismuth amount concentration B2 near the surface of the sintered body and the non-linear resistor 3 is a graph showing a relationship with the energy withstand value of the. That is, in FIG. 4, the value of B2 / B1 is controlled to be larger than 0.6 and the value of B2 / B is changed by adjusting the conditions in the firing process as described above. The results obtained when a large number of non-linear resistors are produced and an energy withstand test is performed by applying an AC voltage of about 5000 V to these non-linear resistors are shown. The amount of bismuth in the sintered body was measured by the ICP method in the same manner as the test method for the distribution of bismuth described above.

As is apparent from FIG. 4, the non-linear resistor having a value of B2 / B larger than 0.5 exhibits excellent energy withstanding characteristics. That is, as described above, since bismuth easily evaporates during firing, in this example, the bismuth amount near the surface of the sintered body is maintained at a level of 50% or more with respect to the added amount. A non-linear resistor having excellent energy withstand characteristics was obtained by controlling the evaporation amount of.

Test on Bismuth Oxide Crystal Phase ... Table 1 Table 1 shows that the value of B2 / B1 is 0.6 <(B2 / B1) <
In the non-linear resistor to be No. 1, the relationship between the combination of the main crystal phase of bismuth oxide (Bi ₂ O ₃ ) in the central part of the sintered body and the surface and the energy withstand value of the non-linear resistor is shown. It is a graph. That is, Table 1 shows that by adjusting the conditions in the firing process as described above,
A large number of non-linear resistors were manufactured by controlling the value of B2 / B1 to be larger than 0.6 and changing the combination of main crystal phases of bismuth oxide in the central portion and near the surface. About 5000V to these non-linear resistors
The results when an energy withstand test is performed by applying the AC voltage of No. 2 are shown. In addition, various combinations of the crystal phase near the center of bismuth oxide and the surface can change the crystal state to α, β, γ, and δ by changing the amount and type of the solid solution component and the heat treatment conditions. It was obtained. The crystal phase was identified by X-ray diffraction after cutting out and crushing the central part and the surface vicinity of the sintered body.

[0036]

[Table 1] As is clear from Table 1, in the non-linear resistor in which the main crystal phase of bismuth oxide (Bi ₂ O ₃ ) of the sintered body is the same crystal phase in the central portion and near the surface, excellent energy withstanding characteristics are obtained. Shows. That is, in this example, the crystalline state was controlled so that the main crystal phase of bismuth oxide (Bi ₂ O ₃ ) of the sintered body was the same crystal phase in the central portion and in the vicinity of the surface, so that excellent energy was obtained. A non-linear resistor having withstand voltage characteristics was obtained.

Test on Zinc Amount in Bismuth Oxide Crystal ... FIG. 5 In FIG. 5, the value of B2 / B1 is 0.6 <(B2 / B1) <
In the non-linear resistor of No. 1, zinc (Zn) contained in the bismuth oxide (Bi ₂ O ₃ ) crystal at the center of the sintered body
3 is a graph showing the relationship between the amount of energy and the energy withstand value of the nonlinear resistor. That is, FIG. 5 shows that B is adjusted by adjusting the conditions in the firing process as described above.
A large number of non-linear resistors were manufactured by controlling the value of 2 / B1 to be greater than 0.6 and changing the amount of zinc contained in the bismuth oxide crystal in the central part of these non-linear resistors. The results obtained when an energy withstand test is performed by applying an AC voltage of about 5000 V to the linear resistor are shown. In this case, in the zinc oxide non-linear resistor,
In general, since many metals such as antimony and bismuth are added to zinc oxide, the solid solution component and the amount of solid solution in the bismuth oxide crystal change if the reaction process during the firing process is different. Therefore, in this example, the solid solution amount of zinc in the bismuth oxide crystal was changed by controlling such a reaction process. Further, the amount of zinc in the bismuth oxide crystal was measured by cutting out the central portion of the sintered body, polishing it, and then performing energy dispersive X-ray spectroscopy analysis of the bismuth oxide crystal.

As is apparent from FIG. 5, the non-linear resistor in which the amount of zinc contained in the bismuth oxide crystal is in the range of 2 to 20 mol exhibits excellent energy withstanding characteristics. That is, in this example, the amount of zinc in the bismuth oxide at the center of the sintered body was 2 to 20 mol%.
By controlling the amount of solid solution of zinc in bismuth oxide so as to be in the range, a non-linear resistor having excellent energy withstand characteristics was obtained.

Although FIG. 5 shows the amount of zinc contained in the bismuth oxide crystal at the center of the sintered body, the amount of zinc contained in bismuth oxide near the surface of the sintered body is also shown in the center. It has the same relationship with the energy withstand value as the part. In fact, the present inventor has found that when the amount of zinc contained in bismuth oxide is in the range of 2 to 20 mol% both in the central portion of the sintered body and in the vicinity of the surface, the nonlinearity of the excellent energy withstand characteristics is excellent. It has been confirmed that a resistor can be obtained.

Test on the amount of antimony in the bismuth oxide crystal ... FIG. 6 In FIG. 6, the value of B2 / B1 is 0.6 <(B2 / B1) <
In the non-linear resistor of No. 1, the relationship between the amount of antimony (Sb) contained in the bismuth oxide (Bi ₂ O ₃ ) crystal at the center of the sintered body and the energy withstand value of the non-linear resistor is shown. It is a graph shown. That is, this FIG.
By adjusting the conditions in the firing process as described above, the value of B2 / B1 is controlled to be larger than 0.6, and the amount of antimony contained in the bismuth oxide crystal at the center is changed. To produce a large number of non-linear resistors, and apply approximately 5000V to these non-linear resistors.
The results when an energy withstand test is performed by applying the AC voltage of No. 2 are shown. In this case, in the zinc oxide non-linear resistor, as described above, zinc oxide contains antimony,
Since many metals such as bismuth are added, the solid solution component and the amount of solid solution in the bismuth oxide crystal change if the reaction process during the firing step is different. Therefore, in this example, similarly to the above-described test for the amount of zinc in the bismuth oxide crystal, the solid solution amount of antimony in the bismuth oxide crystal was changed by controlling such a reaction process. The amount of antimony in the bismuth oxide crystal was also measured by energy dispersive X-ray spectroscopic analysis of the bismuth oxide crystal, similarly to the measurement of the zinc amount described above.

As is apparent from FIG. 6, the amount of antimony contained in the bismuth oxide crystal is 0.3 to 10 mol.
In the non-linear resistor in the range of, excellent energy withstanding characteristics are exhibited. That is, in this example, by controlling the solid solution amount of antimony in bismuth oxide such that the amount of antimony in bismuth oxide in the central portion of the sintered body was in the range of 0.3 to 10 mol%. ,
A non-linear resistor having excellent energy resistance characteristics was obtained.

Although FIG. 6 shows the amount of antimony contained in the bismuth oxide crystal in the center of the sintered body, the amount of antimony contained in the bismuth oxide near the surface of the sintered body is also shown in the center. It has the same relationship with the energy withstand value as the part. In fact, the inventor of the present invention has excellent energy resistance characteristics when the amount of antimony contained in bismuth oxide is in the range of 0.3 to 10 mol% both in the center and near the surface of the sintered body. It has been confirmed that a non-linear resistor can be obtained.

[3. [Effect] As described above, in the present embodiment, the distribution of the amount of bismuth in the sintered body, the bismuth evaporation amount, the bismuth oxide crystal phase, the oxidation, which are influential factors on the energy withstand characteristics of the nonlinear resistor, By controlling the amount of zinc and the amount of antimony in the bismuth crystal within the respective limited ranges, a non-linear resistor having excellent energy withstanding characteristics can be obtained as compared with the conventional case in which these influencing factors were not controlled. be able to.

[4. Other Examples] In the above examples, by selecting or controlling the conditions such as the temperature pattern, the shape of the baking pod, the dimensions, and the baking atmosphere during the baking step, the The distribution of the bismuth amount in the aggregate, the bismuth evaporation amount, the bismuth oxide crystal phase, the zinc amount and the antimony amount in the bismuth oxide crystal were controlled within the respective limited ranges, but the control method of the influencing factors was limited to this. Not something. That is, for example, it can be controlled by changing the condition of the heat treatment process for evaporating the binder component in the molded body, or by changing the condition of the heat treatment process after firing. And, even when any control method of the influencing factors is selected, regardless of such control method, by controlling each influencing factor in each limited range of the present invention, as in the above-described embodiment, excellent It is possible to obtain a non-linear resistor having excellent energy tolerance characteristics.

The composition of the non-linear resistor of the present invention is not limited to the above-mentioned embodiment, and the present invention is a sintered body containing zinc oxide as a main component and at least bismuth and antimony added thereto. It can be similarly applied to all the non-linear resistors used, and can obtain the same excellent effect as the above-mentioned embodiment.

[0046]

As described above, according to the present invention,
Distribution of bismuth amount in sintered body, bismuth evaporation amount, bismuth oxide crystal phase, zinc amount in bismuth oxide crystal in a non-linear resistor using a sintered body containing zinc oxide as a main component and at least bismuth and antimony added By controlling the amount of antimony and the amount of antimony appropriately within each limited range, a non-linear resistor having excellent energy withstanding characteristics that does not break even when absorbing large surge energy is provided. Can be provided.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a basic configuration of a non-linear resistor according to the present invention.

FIG. 2 is a graph showing the relationship between the bismuth amount concentration ratio B2 / B1 in the vicinity of the surface of the nonlinear resistor with respect to the center of the sintered body and the energy withstand value of the nonlinear resistor.

FIG. 3 is a graph showing the relationship between the bismuth amount concentration ratio B1 / B of the central portion with respect to the added bismuth amount concentration of the sintered body in the nonlinear resistor and the energy withstand value of the nonlinear resistor.

FIG. 4 is a bismuth amount concentration ratio B2 / B near the surface with respect to the added bismuth amount concentration of the sintered body in the non-linear resistor,
The graph which shows the relationship with the energy withstand value of the nonlinear resistor.

FIG. 5 is a graph showing the relationship between the amount of zinc in the bismuth oxide crystal at the center of the sintered body of the nonlinear resistor and the energy withstand value of the nonlinear resistor.

FIG. 6 is a graph showing the relationship between the amount of antimony in the bismuth oxide crystal at the center of the sintered body of the nonlinear resistor and the energy withstand value of the nonlinear resistor.

[Explanation of symbols]

 1: Sintered body 2: High resistance layer 3: Electrode

Claims (6)

[Claims] 1. A main component is zinc oxide (ZnO), and at least bismuth (Bi) and antimony (S) as additives.
In a non-linear resistor using a sintered body to which b) is added, the bismuth amount concentration at the center of the sintered body is B1 (wt).
%), And when the bismuth amount concentration near the surface is B2 (wt%), these ratios B2 / B1 are in the range of 0.6 <(B2 / B1) <1. Linear resistor. 2. When the added bismuth amount concentration with respect to the zinc oxide is B (wt%), the ratio B1 / B between the added bismuth amount concentration B and the bismuth amount concentration B1 at the center of the sintered body is , 0.7 <(B1 / B). The non-linear resistor according to claim 1, wherein 3. When the added bismuth amount concentration with respect to the zinc oxide is B (wt%), the ratio B2 / B between the added bismuth amount concentration B and the bismuth amount concentration B2 near the surface of the sintered body is , 0.5 <(B2 / B). 3. The nonlinear resistor according to claim 1 or 2, wherein 4. The main crystal phase of bismuth oxide (Bi ₂ O ₃ ) formed in the sintered body is the same crystal phase in the central portion and near the surface of the sintered body. The nonlinear resistor according to any one of 1 to 3. 5. The amount of zinc (Zn) contained in the bismuth oxide (Bi ₂ O ₃ ) crystal formed in the sintered body is
2 at both the center and near the surface of the sintered body
It exists in the range of -20 mol%, The nonlinear resistor as described in any one of Claims 1-4. 6. The amount of antimony (Sb) contained in the bismuth oxide (Bi ₂ O ₃ ) crystal formed in the sintered body is both in the center and near the surface of the sintered body. It exists in the range of 0.3-10 mol%, The nonlinear resistor as described in any one of Claims 1-5 characterized by the above-mentioned.