JPWO2019146065A1 - Materials for current-voltage non-linear resistors, current-voltage non-linear resistors and their manufacturing methods - Google Patents

Abstract

The method for producing a current-voltage non-linear resistor contains zinc oxide as a main component raw material and at least bismuth oxide, antimony oxide, manganese oxide, cobalt oxide, nickel oxide, rare earth element R, boron and silver as auxiliary component raw materials. This is a method of firing a mixture. The relative ratio of the average particle size (D50s) of the subcomponent raw material to the average particle size (D50z) of the zinc oxide in the mixture is D50s / D50z ≦ 0.60. The average particle size (D50z) of zinc oxide is 700 nm or less. The mixture contains 0.005 to 0.04 wt% of the boron in terms of B ₂ O ₃ , and 0.005 to 0.04 wt% of the silver in terms of Ag ₂ O. The relative ratio of boron to silver satisfies the relationship of 0.125 ≦ B ₂ O ₃ / Ag ₂ O ≦ 1.00.

Description

Embodiments of the present invention relate to materials for current-voltage non-linear resistors, current-voltage non-linear resistors and methods for manufacturing them.

Generally, an overvoltage protection device such as a lightning arrester or a surge absorber is used to protect a power system or an electronic device circuit from an abnormal voltage. Overvoltage protection devices such as these have current-voltage non-linear resistors that exhibit insulation characteristics under normal voltage, but exhibit low resistance characteristics when an abnormal voltage is applied, and are suitable for suppressing overvoltage. It is valid.

This current-voltage non-linear resistor contains zinc oxide (ZnO) as a main component and at least one kind of metal oxidation as an additive in order to obtain voltage non-linear resistance characteristics (hereinafter, also referred to as non-linear resistance characteristics). A ceramic body (sintered body) obtained by mixing, granulating, molding, and sintering a mixture to which a substance has been added is provided. In fact, when applying a current-voltage non-linear resistor to an overvoltage protection device, the side surface of the sintered body is provided with an insulating layer of electrical insulating material to prevent flash over from the side surface during surge absorption. It is used after being formed.

Further, with the recent economic recession, in order to reduce the transmission cost in the electric power system, there is a demand for miniaturization and high performance of the equipment constituting the transmission / transformation facility. A current-voltage non-linear resistor containing zinc oxide as a main component is applied to a lightning arrester due to its excellent non-linear resistance characteristics. Specifically, a plurality of current-voltage non-linear resistors are laminated. It constitutes a lightning arrester. That is, if the current-voltage non-linear resistor applied to the arrester can be increased in resistance, the number of current-voltage non-linear resistors provided stacked on the arrester can be reduced, and power transmission / transformation can be performed. The equipment can be downsized.

In order to increase the resistance of the current-voltage non-linear resistor, the content of sub-components such as Bi ₂ O ₃ , Co ₂ O ₃ , MnO, Sb ₂ O ₃ , and NiO is limited, and ZnO is further added. A current-voltage non-linear resistor in which the crystal phase of Bi ₂ O ₃ contained in the sintered body as the main component is limited is known. In this current-voltage non-linear resistor, the resistance value is high and excellent non-linear resistance characteristics can be obtained.

Further, in a current-voltage non-linear resistor in which zinc oxide is the main component and Bi ₂ O ₃ , Co ₂ O ₃ , MnO, Sb ₂ O _{3 and the} like are added, resistance is further added by adding a rare earth oxide. Current-voltage non-linear resistors with high values and excellent non-linear resistance characteristics are also known.

In addition, the varistor voltage (V _1mA ), which is the voltage when a current of 1mA of commercial frequency of the current-voltage non-linear resistor used in the conventional high-performance tank arrester is energized, is about 200V / mm to 600V / mm. is there.

Here, in recent years, the characteristics required for current-voltage non-linear resistors have become more and more severe, and in order to sufficiently miniaturize equipment such as lightning arresters and surge absorbers that make up power transmission and transformation equipment, current-voltage In the voltage non-linear resistor, for example, a varistor voltage of 600 V / mm or more is required to be further increased.

However, the conventional techniques as described above have not been able to fully satisfy these requirements.
For example, in order to increase the varistor voltage of the current-voltage non-linear resistor to 600 V / mm or more, the grain growth of zinc oxide particles, which is the main component, must be further suppressed, and Sb ₂ O having the suppressing effect. _It is necessary to further add subcomponents such as ₃ and rare earth elements. However, as the amount of these sub-components added increases, the resistance can be increased, while the amount of spinel particles containing Zn ₇ Sb ₂ O ₁₂ as a main component, which is an insulator, also increases, so that the current-voltage is increased. In some cases, the current flow becomes non-uniform throughout the non-linear resistor, and the non-linear resistance characteristics deteriorate.

In addition, in the energy capacity of the current-voltage non-linear resistor, it is necessary to absorb a commercial frequency of 50 to 60 Hz, a switching surge on the order of ms, and a lightning impulse surge on the order of μs. Since the generated energy per unit volume at the time of absorbing surge energy increases due to the resistance, it is necessary to improve the various energy withstand characteristics.

Japanese Unexamined Patent Publication No. 2001-307909 Patent No. 294178 Patent No. 2933881 Patent No. 2940486 Patent No. 3165410 Japanese Unexamined Patent Publication No. 2001-68308

The problem to be solved by the present invention is to provide a material for a current-voltage non-linear resistor, a current-voltage non-linear resistor, and a method for manufacturing the same, which can achieve high resistance and have excellent non-linear resistance characteristics and energy capacity. It is to be.

The method for producing a current-voltage non-linear resistor of the embodiment uses zinc oxide as a main component raw material, and at least bismuth oxide, antimony oxide, manganese oxide, cobalt oxide, nickel oxide, rare earth element R, and trivalent as auxiliary component raw materials. The mixture containing the element, boron and silver is fired. The relative ratio of the average particle size (D50s) of the subcomponent raw material to the average particle size (D50z) of the zinc oxide in the mixture is D50s / D50z ≦ 0.60. The average particle size (D50z) of zinc oxide is 700 nm or less. The mixture contains 0.005 to 0.04 wt% of the boron in terms of B ₂ O ₃ , and 0.005 to 0.04 wt% of the silver in terms of Ag ₂ O. The relative ratio of boron to silver satisfies the relationship of 0.125 ≦ B ₂ O ₃ / Ag ₂ O ≦ 1.00.

FIG. 5 is a cross-sectional view showing a current-voltage non-linear resistor of the embodiment. A graph showing the relationship between D50s / D50z and a non-linearity coefficient (V _{10 kA} / V _{1 mA} ) for sample numbers 1 to 12 of Examples.

Hereinafter, the current-voltage non-linear resistor of the embodiment, a method for manufacturing the same, and a material for the current-voltage non-linear resistor will be described with reference to the drawings.

FIG. 1 is a cross-sectional view showing an example of the current-voltage non-linear resistor 10 of the embodiment.
As shown in FIG. 1, the current-voltage non-linear resistor 10 of the embodiment is formed on the sintered body 20, the insulating layer 30 covering the side surface of the sintered body 20, and the upper and lower surfaces of the sintered body 20. The electrode 40 is provided.
The sintered body 20 is a mixture containing zinc oxide as a main component raw material and at least bismuth oxide, antimony oxide, manganese oxide, cobalt oxide, nickel oxide, rare earth element R, trivalent element, boron and silver as auxiliary component raw materials. It is made by firing. Further, the sintered body 20 contains 0.005 to 0.04 wt% of boron in terms of B ₂ O _3, and contains 0.005 to 0.04 wt% of silver in terms of Ag ₂ O. The relative ratio of boron to silver satisfies the relationship of 0.125 ≦ B ₂ O ₃ / Ag ₂ O ≦ 1.00.

Next, the material for the current-voltage non-linear resistor 10 (material for the current-voltage non-linear resistor) of the embodiment will be described.
The material for the current-voltage non-linear resistor 10 of the embodiment uses zinc oxide as a main component raw material, and at least bismuth oxide, antimony oxide, manganese oxide, cobalt oxide, nickel oxide, rare earth element R, 3 as auxiliary component raw materials. It consists of a mixture containing valence elements, boron and silver. Further, the relative ratio of the average particle size (D50s) of the auxiliary component raw material to the average particle size (D50z) of the zinc oxide raw material in the mixture is D50s / D50z ≦ 0.60, and the average particle size of the zinc oxide raw material is It is 700 nm or less. Also, boron is converted to B ₂ O ₃ and contains 0.005 to 0.04 wt%, silver is converted to Ag ₂ O and contains 0.005 to 0.04 wt%, and the relative ratio of boron to silver. Satisfies the relationship of 0.125 ≦ B ₂ O ₃ / Ag ₂ O ≦ 1.00.

In the material for the current-voltage non-linear resistor 10 of the embodiment, the mixture uses zinc oxide as a main component, but here, the "main component" is 90 mol% or more in the mixture. Means that

The relative ratio of the average particle size (D50s) of the auxiliary component raw material to the average particle size (D50z) of the zinc oxide raw material in the mixture is D50s / D50z ≦ 0.60, and the average particle size of the zinc oxide raw material (D50z). Is 700 nm or less.

The average particle size (D50s) of the auxiliary component raw material is made smaller than the average particle size (D50z) of zinc oxide (hereinafter, also referred to as zinc oxide raw material) which is the main component raw material, that is, D50s / D50z is made smaller. Therefore, the auxiliary component raw material can be uniformly dispersed in the zinc oxide raw material. As a result, in the firing process for forming the sintered body 20 from the mixture of the zinc oxide raw material and the auxiliary component raw material, the grain growth of the zinc oxide particles proceeds uniformly and the effect of suppressing the grain growth of the zinc oxide particles is achieved. Since the possessing Sb ₂ O ₃ and rare earth elements also work effectively, it is possible to increase the resistance of the obtained current-voltage non-linear resistor 10 even if the amount of the sub-component added is small. Further, by reducing D50s / D50z, the fine structure is made uniform and the sinterability is improved, so that the sinter 20 becomes denser and the porosity of the sinter 20 is reduced. Therefore, a current-voltage non-linear resistor 10 having excellent non-linear resistance characteristics and energy withstand capacity can be obtained.

On the other hand, when D50s / D50z> 0.60, the additive cannot work effectively, and conversely, the grain growth of zinc oxide particles is hindered and the sinterability is lowered, so that the non-linearity and the energy tolerance are reduced. Get worse. Further, by setting the average particle size of the zinc oxide raw material to 700 nm or less, the reaction between the auxiliary component raw material and the zinc oxide raw material proceeds efficiently, so that the non-linear resistance characteristic is improved, but when it exceeds 700 nm, the non-linear resistance characteristic is improved. No improvement is observed.

From the above, in the material for the current-voltage non-linear resistor, the relative ratio D50s / D50z of the average particle size D50s of the auxiliary component raw material to the average particle size D50z of the zinc oxide raw material is set to 0.60 or less, and the zinc oxide raw material The average particle size D50z of is 700 nm or less. From the viewpoint of high resistance, non-linear resistance characteristics and improvement of energy resistance, D50s / D50z is preferably 0.50 or less, and the average particle size (D50z) of the zinc oxide raw material is preferably 600 nm or less.
The lower limit of D50s / D50z is not particularly limited, but when D50s / D50z becomes excessively small, that is, when the average particle size D50s of the auxiliary component raw material becomes excessively smaller than the average particle size D50z of the zinc oxide raw material, the auxiliary component raw material D50s / D50z is preferably 0.35 or more because the particles may aggregate and it may be difficult to disperse uniformly. Further, the lower limit of the average particle size D50z of the zinc oxide raw material is not particularly limited, but if the average particle size D50z of the zinc oxide raw material is excessively small, the uniform dispersion of the zinc oxide raw material and the auxiliary component raw material is hindered, and the sinterability deteriorates. It is preferably 350 nm or more because there is a risk of zinc oxide.

Further, in the mixture, the average particle size (D50t) of all the raw materials including the zinc oxide raw material and the auxiliary component raw material is preferably 750 nm or less. By setting the average particle size (D50t) of all the raw materials to 750 nm or less, the reaction between the auxiliary component raw material and the zinc oxide raw material proceeds efficiently, and the non-linear resistance characteristic can be improved. The average particle size (D50t) of all raw materials is more preferably 650 nm or less.

Here, for the average particle size D50s of the auxiliary component raw materials in the powder mixture, the average particle size D50z of zinc oxide, and the average particle size D50t of all the raw materials, for example, a laser diffraction / scattering type particle size distribution measuring device is used. It can be calculated by measuring the particle size distribution (laser diffraction / scattering type particle size distribution measurement method). As the laser diffraction / scattering type particle size distribution device, for example, "Microtrack MT3000II series" manufactured by Nikkiso Co., Ltd. can be used.
The average particle size (D50s, D50z, D50t) referred to in this embodiment is called the median diameter, and the particle size distribution is measured by the above-mentioned measuring method, and the cumulative particle size frequency is 50%. The diameter is defined as the average particle size (D50s, D50z, D50t).

Further, the auxiliary component raw materials of the material for the current-voltage non-linear resistor 10 of the embodiment include at least bismuth oxide, antimony oxide, manganese oxide, cobalt oxide, nickel oxide, rare earth element R, boron and silver.

In addition, boron, which is a sub-component of the mixture, is converted to B ₂ O ₃ and contains 0.005 to 0.04 wt%, and silver is converted to Ag ₂ O and contains 0.005 to 0.04 wt%. The relative ratio of boron to silver satisfies the relationship of 0.125 ≦ B ₂ O ₃ / Ag ₂ O ≦ 1.00.
By satisfying the relative ratio of B ₂ O ₃ and Ag ₂ O to 0.125 ≦ B ₂ O ₃ / Ag ₂ O ≦ 1.00 while the respective contents of boron and silver are within a predetermined range. Excellent non-linear resistance characteristics and energy tolerance are obtained. On the other hand, if the boron and silver contents deviate from these ranges, both the non-linear resistance property and the energy tolerance, or one of them, deteriorates.
From the viewpoint of non-linear resistance characteristics and energy tolerance, the content of boron in the mixture is preferably 0.006 wt% or more, preferably 0.03 wt% or less in terms of B ₂ O ₃ . Similarly, the silver content in the mixture is preferably 0.01 wt% or more, preferably 0.03 wt% or less in terms of Ag ₂ O. Further, the relative ratio of B ₂ O ₃ and Ag ₂ O is preferably 0.20 ≦ B ₂ O ₃ / Ag ₂ O ≦ 1.00.

In addition, as subcomponents contained in the mixture, Bi ₂ O ₃ was converted into Bi ₂ O ₃ , Sb ₂ O ₃ , Co ₂ O ₃ , MnO, and NiO, respectively, and Bi ₂ O ₃ was 0.30 to 0.80 mol% and Sb ₂ It may contain 01.50 to 3.50 mol% of O ₃ , 0.5 to 2.00 mol% of MnO, 0.30 to 1.50 mol% of Co ₂ O _3, and 1.50 to 3.50 mol% of NiO. preferable.

Bismuth oxide is a component that exists at the grain boundary of zinc oxide, which is the main component, and exhibits non-linear resistance characteristics. However, when the content converted to Bi ₂ O ₃ is smaller than 0.30 mol%, The effect of exhibiting this non-linear resistance characteristic cannot be sufficiently obtained, and the energy tolerance may deteriorate. Further, when the content is larger than 0.80 mol%, the non-linear resistance characteristic may be deteriorated. From these facts, the content of bismuth oxide is preferably 0.30 to 0.80 mol% in terms of Bi ₂ O ₃ .

Antimony oxide is a component that forms spinel particles with zinc oxide, suppresses grain growth of zinc oxide particles during sintering, has a function of homogenizing, and has an effect of improving non-linear resistance characteristics. However, when the content converted to Sb ₂ O ₃ is smaller than 1.50 mol%, the effect of improving the non-linear resistance characteristic cannot be sufficiently obtained, and the energy tolerance may deteriorate. Further, when the content is larger than 3.50 mol%, the insulating component inside the sintered body increases, and the energy withstand property characteristics may deteriorate. From these facts, the content of antimony oxide is preferably 1.50 to 3.50 mol% in terms of Sb ₂ O ₃ .

Manganese oxide is an effective component that dissolves mainly in spinel particles to greatly improve non-linear resistance characteristics, but when the content converted to MnO is smaller than 0.50 mol%, this non-linear resistance There is a possibility that the effect of improving the linear resistance characteristics cannot be sufficiently obtained. On the other hand, when the content is larger than 2.00 mol%, the insulating component inside the sintered body increases, and the energy tolerance may deteriorate. From these facts, it is preferable that the content of manganese oxide is 0.50 to 2.00 mol% in terms of MnO.

Cobalt oxide is an effective component mainly dissolved in spinel particles to greatly improve non-linear resistance characteristics, but when the content converted to Co ₂ O ₃ is smaller than 0.30 mol%. May not be able to sufficiently obtain the effect of improving this non-linear resistance characteristic. On the other hand, if the content is larger than 1.50 mol%, the insulating component inside the sintered body increases, and the energy withstand capacity may deteriorate. From these facts, the content of cobalt oxide is preferably 0.30 to 1.50 mol% in terms of Co ₂ O ₃ .

Nickel oxide is an effective component mainly dissolved in spinel particles to greatly improve non-linear resistance characteristics, but when the content converted to NiO is smaller than 1.50 mol%, this is used. There is a possibility that the effect of improving the non-linear resistance characteristic cannot be sufficiently obtained. On the other hand, when the content is larger than 3.50 mol%, the insulating component inside the sintered body increases, and the energy tolerance may deteriorate. From these facts, it is preferable that the content of nickel oxide is 1.50 to 3.50 mol% in terms of NiO.

In addition, the mixture contains a rare earth element as a subcomponent. Preferably, at least one rare earth element among yttrium (Y), europium (Eu), elibium (Er), thulium (Tm), gadolinium (Gd), dysprodium (Dy), holmium (Ho), and itteribium (Yb). By including R and containing 0.10 to 0.50 mol% in terms of R ₂ O ₃ , excellent non-linear resistance characteristics and energy tolerance can be obtained without increasing the insulating component inside the sintered body. .. Here, when the content of the rare earth element R is smaller than 0.10 mol% in terms of R ₂ O ₃ , the non-linearity deteriorates, while when it is larger than 0.50 mol%, the energy tolerance May worsen.

In addition, the mixture contains a trivalent element as a subcomponent. Preferably, it contains at least one trivalent element of aluminum (Al), gallium (Ga), and indium (In), and is 0.003 to 0.010 mol% in terms of Al ³⁺ , Ga ³⁺ , and In ³⁺ , respectively. It is preferable to include it. The trivalent element is an effective component for solid solution in ZnO particles to greatly improve the non-linear resistance characteristics, but when the content is larger than 0.010 mol%, the non-linear resistance characteristics deteriorate. There is a risk of

The material for the current-voltage non-linear resistor 10 of the embodiment has been described above, but the current-voltage non-linear resistor 10 of the embodiment is formed by firing the material for the current-voltage non-linear resistor 10. It includes a sintered body 20.
Further, the 50% fracture strength of the mechanical strength of the sintered body 20 is preferably 140 MPa or more.
The mechanical strength of the sintered body can be measured by a 4-point bending test in accordance with JIS R1604. When the 50% fracture strength of the mechanical strength of the sintered body is 140 MPa or more, an excellent energy withstand capacity for absorbing lightning impulse surge can be obtained.

Further, in the current-voltage non-linear resistor 10 of the present embodiment, the varistor voltage (V _{1 mA} ), which is the voltage when a current of a commercial frequency of 1 mA is applied, can be 900 V / mm or more.

Next, a method of manufacturing the current-voltage non-linear resistor 10 of the present embodiment will be described.
The method for producing the current-voltage non-linear resistor 10 uses zinc oxide as a main component raw material and at least bismuth oxide, antimony oxide, manganese oxide, cobalt oxide, nickel oxide, and rare earth element R as auxiliary component raw materials. This method includes a step of firing a mixture (material for a current-voltage non-linear resistor) containing a trivalent element, boron and silver to prepare a sintered body 20.
Hereinafter, a specific description will be given.

First, zinc oxide, which is the main component raw material, and at least bismuth oxide, antimony oxide, manganese oxide, cobalt oxide, nickel oxide, rare earth element R, boron and silver are contained as auxiliary component raw materials, and boron is converted to B ₂ O ₃ . It contains 0.005 to 0.04 wt%, contains 0.005 to 0.04 wt% of silver in terms of Ag ₂ O, and the relative ratio of boron to silver is 0.125 ≤ B ₂ O ₃ / Ag. ₂ Weigh so as to satisfy the relationship of O ≦ 1.00 to prepare a mixture.
When bismuth oxide, antimony oxide, manganese oxide, cobalt oxide, nickel oxide, rare earth element R and trivalent element are contained as auxiliary component raw materials, Bi ₂ O ₃ , Sb ₂ O ₃ , Co ₂ O ₃ and MnO, respectively. , NiO, R ₂ O ₃ , Ag ₂ O and B ₂ O ₃ , Bi ₂ O ₃ 0.30 to 0.80 mol%, Sb ₂ O ₃ 1.50 to 3.50 mol%, MnO Is contained in an amount of 0.50 to 2.00 mol%, Co ₂ O ₃ is contained in an amount of 0.30 to 1.50 mol%, NiO is contained in an amount of 1.50 to 3.50 mol%, and R ₂ O ₃ is contained in an amount of 0.10 to 0.50 mol%. Is preferable. When a trivalent element is contained, at least one of aluminum (Al), gallium (Ga), and indium (In) is contained, which is converted into Al ³⁺ , Ga ³⁺ , and In ³⁺ , respectively. It is preferably contained in an amount of 003 to 0.010 mol%.

Subsequently, the prepared mixture and a binder solution adjusted so that the content of the mixture was 30 to 60% by weight were put into a wet pulverizer, and the average particle size of the zinc oxide raw material was 700 nm or less and A slurry is prepared by mixing while pulverizing so that the relative ratio of the average particle size (D50s) of the auxiliary component raw material to the average particle size (D50z) of the zinc oxide raw material is D50s / D50z ≦ 0.60. As the binder solution, for example, an aqueous solution obtained by mixing water and an organic binder such as polyvinyl alcohol is used.

Here, as the wet pulverizing apparatus, for example, a circulation type apparatus using zirconia beads having a diameter of 0.05 to 0.3 mm is used. Further, the bead filling rate in the vessel in the wet pulverizer is 35 to 95%, the peripheral speed of the stirring rotor is 500 to 1500 rpm, and the circulation flow rate can be operated under the conditions of 5 to 50 L / min.

Subsequently, the prepared slurry is sprayed and granulated by a rotary disk method or a pressure nozzle method to prepare granules having a cumulative average particle size (median diameter D50) of 45 to 90 μm.

The obtained granules are molded into a columnar shape by, for example, a hydraulic press molding machine to prepare a molded product.

Subsequently, the molded product is heated to a first temperature, 350 to 500 ° C., and maintained at this temperature for, for example, 1 to 3 hours to remove the binder solution.

Next, the molded product is heated to a second temperature of 900 to 1300 ° C., and the compact is fired while being maintained at this temperature for, for example, 2 hours or more. The firing is performed by, for example, using a tunnel-type continuous furnace and installing the molded body in a refractory container such as alumina or mullite. The heating rate from the first temperature to the second temperature is preferably 25 to 100 ° C./hour from the viewpoint of temperature uniformity in the object to be fired and the lead time of the firing process.

After the lapse of the maintenance time of the second temperature, the fired compact is cooled. Although the cooling method is not particularly limited, the cooling rate at the time of cooling is preferably 100 to 200 ° C./hour from the viewpoint of temperature uniformity in the object to be fired and the lead time of the firing process.
Through this cooling step, the sintered body 20 is obtained.

Next, an inorganic insulating material such as glass frit, which is an electrically insulating material, is applied or sprayed on the side surface of the cooled columnar sintered body 20, and heat-treated at a temperature of 300 to 500 ° C. for 1 to 5 hours. The insulating layer 30 is formed.
Further, both upper and lower end surfaces of the sintered body 20 are polished, and the above-mentioned conductive material is sprayed on the polished surfaces to form an electrode 40.
The order in which the step of forming the insulating layer 30 and the step of forming the electrode 40 are performed is not particularly limited, and any of them may be performed first.

In this way, the current-voltage non-linear resistor 10 is manufactured through the above steps.

As described above, according to the current-voltage non-linear resistor 10 and the manufacturing method thereof according to the present embodiment, oxidation which is a main component in the raw material of the sintered body 20 constituting the current-voltage non-linear resistor 10. The average particle size of the zinc oxide raw material is 700 nm or less, and the relative ratio of the average particle size (D50s) of the auxiliary component raw material to the average particle size (D50z) of the zinc oxide raw material is D50s / D50z ≦ 0.6. , Spinel particles and other raw materials that have the effect of suppressing the grain growth of zinc oxide particles in the sintered body 20 are uniformly dispersed throughout the fine structure, so that the auxiliary component raw materials work effectively and the fine structure is uniform. Be made. Further, since the sinterability is improved by uniformly dispersing the spinel particles and other auxiliary component raw materials, the sintered body 20 can be made denser and the zinc oxide particles in the sintered body 20 can be made finer. As a result, the varistor voltage (V _{1 mA} ) of the current-voltage non-linear resistor 10 having the sintered body 20 can be increased to 900 V / mm or more. In addition, boron, which is an auxiliary component raw material, is converted to B ₂ O ₃ and contains 0.005 to 0.04 wt%, and silver is converted to Ag ₂ O and contains 0.005 to 0.04 wt%. Excellent, non-linear resistance in the current-voltage non-linear resistor 10 by limiting the component ratio so that the relative ratio of boron to silver is 0.125 ≤ B ₂ O ₃ / Ag ₂ O ≤ 1.00. You can enjoy linear resistance characteristics and energy withstand.

According to at least one embodiment described above, by defining the average particle diameters D50z and D50s / D50z of zinc oxide and adjusting the addition amounts of boron and silver, high resistance can be achieved and non-linear resistance can be achieved. A current-voltage non-linear resistor with excellent characteristics and energy withstand capability can be obtained.

Next, each characteristic of the current-voltage non-linear resistor of the present embodiment will be specifically described below.

(Example 1)
In Example 1, in the mixture for producing the sintered body, the average particle size of the zinc oxide raw material (D50z) and the average particle size of the subcomponents (D50s) are relative to the average particle size (D50z) of the zinc oxide raw material. The effect of the ratio D50s / D50z on the varistor voltage (V _1mA ), non-linear resistance characteristic and energy withstand characteristic of the current-voltage non-linear resistor will be described.

First, in producing the current-voltage non-linear resistor, zinc oxide (ZnO) was used as the main component of the raw material of the sintered body. Bismuth oxide (Bi ₂ O ₃ ) is 0.50 mol%, antimony trioxide (Sb ₂ O ₃ ) is 2.00 mol%, manganese oxide (MnO) is 0.50 mol%, and cobalt oxide (Co) is used as an auxiliary component raw material. ₂ O ₃ ) is 1.00 mol%, nickel oxide (NiO) is 2.00 mol%, yttrium oxide (Y ₂ O ₃ ) is 0.30 mol% as a rare earth element, and boron (B ₂ O ₃ ) is 0.02 wt%. , Silver (Ag ₂ O) 0.02 wt%, and Aluminum as a trivalent element in an aqueous solution of aluminum hydroxide (Al ₂ O ₃ ), adjusted to add 0.005 mol%, zinc oxide raw material and these subcomponents. A mixture of raw materials was prepared. The balance is zinc oxide.

The mixture adjusted as described above and a binder solution composed of water and an organic binder adjusted so that the content of the mixture was 40% by weight were put into a circulation type wet pulverizer. Further, in the wet pulverizer, the average particle size of zinc oxide (D50z), which is the main component, is adjusted by adjusting the particle size of the zirconia beads, the bead filling rate in the vessel, the peripheral speed of the stirring rotor, the circulation flow rate, and the mixing time. ), The average particle size of all the subcomponents (D50s), and the average particle size of all the raw materials including the zinc oxide raw material and the subcomponent raw materials (D50t) were controlled to be the values shown in Table 1. By pulverization and mixing treatment in this wet pulverizer, a uniformly mixed slurry was obtained.
Here, the average particle size (D50z) of zinc oxide and the average particle size (D50s) of all subcomponents are obtained by using a slurry collected from a wet pulverizer with a laser diffraction / scattering type particle size distribution measuring device (manufactured by Nikkiso Co., Ltd.). It was measured using "Microtrack MT3000II series"). Moreover, this average particle diameter is an average particle diameter in the median diameter.

Subsequently, this slurry was spray-granulated with a spray dryer so that the cumulative average particle size was 45 to 90 μm. The obtained granulated powder was made into a columnar molded body having a diameter of 125 mm and a thickness of 30 mm by a hydraulic press molding machine.

Subsequently, the molded product was heated to a first temperature of 500 ° C. and maintained at this temperature for 2 hours to remove organic binders and the like.
Next, the molded product was heated to a second temperature of 1050 ° C., maintained at this temperature for 3 hours, and fired. In addition, firing was carried out by installing a molded body in a refractory container of mullite using a tunnel type continuous furnace. Further, the heating rate from the first temperature of 500 ° C. to each firing temperature of the second temperature of 1050 ° C. was set to 100 ° C./hour.

After the lapse of the maintenance time of the second temperature, the fired molded product was cooled to 750 ° C. or lower. The cooling rate for cooling to a temperature of 750 ° C. or lower was set to 100 ° C./hour. Through this cooling step, a sintered body was obtained.

Subsequently, a glass frit was applied to the side surface of the sintered body, which was a cooled molded product, and heat-treated at a temperature of 500 ° C. for 2 hours to form an insulating layer. Further, the upper and lower end surfaces of the sintered body were polished, and aluminum was sprayed onto the polished surfaces to form electrodes to obtain a current-voltage non-linear resistor.

The varistor voltage (V _{1 mA} ), non-linear resistance characteristics, and energy withstand capacity were evaluated for the obtained current-voltage non-linear resistors of sample numbers 1 to 12.

The varistor voltage (V _{1 mA} ), which is the voltage when a current of a commercial frequency of _{1 mA} was applied, was measured according to JEC0202-1994. It was confirmed that the value of this varistor voltage (V _{1 mA} ) was 900 V / mm or more.

In the evaluation of the non-linear resistance characteristic, the above-mentioned varistor voltage (V _{1 mA} ) and the voltage (V _{10 kA} ) when an 8 × 20 μs impulse current was passed _{10 kA} were measured, and the ratio (V _{10 kA} / V _{1 mA} ) was measured. It was evaluated as a non-linearity coefficient. The smaller the value of the non-linearity coefficient, the better the non-linear resistance characteristic. In Example 1, the non-linearity coefficient of 1.300 or less was evaluated as good.

In the evaluation of energy withstand, the energy value (J / cc) absorbed by the current-voltage non-linear resistor by continuously applying a commercial frequency voltage (50 Hz) 1.3 times the varistor voltage (V _{1 mA} ). Was measured, and the energy withstand capacity was evaluated based on this energy value (J / cc). Here, "until destruction" means until the AE detector detects that a crack has occurred in the current-voltage non-linear resistor. It is shown that the larger the value of this energy value (J / cc) is, the more excellent the energy withstand is. In this example, the one having an energy withstand of 400 J / cc or more was evaluated as good.
In each of the above evaluation tests, 10 pieces of each current-voltage non-linear resistor of sample numbers 1 to 12 were prepared, 10 pieces were tested, and the average of them was used for evaluation.

Table 1 shows the average particle size (D50t) of all the raw materials including the zinc oxide raw material and the auxiliary component raw materials, the average particle size of zinc oxide (D50z), and D50s in the current-voltage non-linear resistors of sample numbers 1 to 12. It shows / D50z, varistor voltage (V _1mA ), non-linearity coefficient (V _10kA / V _1mA ) and energy withstand. In Table 1, * marks are comparative examples showing samples that are outside the scope of this embodiment.
Further, FIG. 2 is a diagram showing the relationship between D50s / D50z and the non-linearity coefficient (V _{10 kA} / V _{1 mA} ) for sample numbers 1 to 12.

As shown in Table 1, in each of the current-voltage non-linear resistors according to the present embodiment, the varistor voltage (V _{1 mA} ) is 900 V / mm or more, and the non-linearity coefficient (V _{10 kA} / V _{1 mA} ) is 1. It was found that it was smaller than .300 and the energy withstand capacity was larger than 400 J / cc. Further, it was found that the current-voltage non-linear resistor according to the present embodiment has higher resistance than the comparative example, and has excellent non-linear resistance characteristics and energy tolerance.

Further, as shown in FIG. 2, by setting D50s / D50z to 0.60 or less, the non-linearity coefficient (V _{10 kA} / V _{1 mA} ) in the current-voltage non-linear resistor was reduced.

From the above results, the relative ratio of the average particle size (D50s) of the auxiliary component raw material to the average particle size (D50z) of the zinc oxide raw material is D50s / D50z ≦ 0.60, and the average particle size of the zinc oxide raw material is It is 700 nm or less, contains 0.005 to 0.04 wt% of boron in terms of B ₂ O ₃ , 0.005 to 0.04 wt% of silver in terms of Ag ₂ O, and is relative to silver of boron. A current-voltage non-linear resistor having a sintered body obtained by firing a mixture having a ratio satisfying the relationship of 0.125 ≦ B ₂ O ₃ / Ag ₂ O ≦ 1.00 can be increased in resistance. It has been found that excellent non-linear resistance characteristics and energy withstand are obtained.

(Example 2)
In Example 2, the influence of the boron and silver component contents on the energy withstand property of the current-voltage non-linear resistor in the mixture for producing the sintered body will be described.

First, among the raw material components of the sintered body used to prepare the sample number 4 in Example 1, boron and silver were added to a mixture having a similar component composition other than boron and silver, and the samples shown in Table 2 were added. The values were adjusted to be the values of No. 13 to Sample No. 24, and a mixture consisting of a zinc oxide raw material and these subcomponent raw materials was prepared.
Subsequent steps for producing the current-voltage non-linear resistor were the same as in Example 1 described above, and a current-voltage non-linear resistor was obtained.
In each sample, the average particle size (D50t) of all raw materials was 695 nm, the average particle size of zinc oxide (D50z) was 700 nm, and D50s / D50z was 0.50. The condition was controlled. The average particle size (D50t) of all raw materials, the average particle size of zinc oxide (D50z), and the average particle size (D50s) of all subcomponents were measured by the same method as in Example 1.

The varistor voltage (V _{1 mA} ), non-linear resistance characteristics, and energy withstand capacity were evaluated for the obtained current-voltage non-linear resistors of sample numbers 13 to 24. The experimental conditions, experimental methods, and evaluation criteria for evaluating the varistor voltage (V _{1 mA} ), non-linear resistance characteristics, and energy tolerance were the same as the experimental conditions and methods of Example 1 described above.
In each of the above evaluation tests, 10 pieces of each current-voltage non-linear resistor of sample numbers 13 to 24 were prepared, 10 pieces were tested, and the average of them was used for evaluation.

Table 2 shows the composition components of boron and silver, the varistor voltage (V _{1 mA} ), and the non-linearity coefficient in the current-voltage non-linear resistors of sample No. 4 (see Table 1) and sample numbers 13 to 24. V _{10 kA} / V _{1 mA} ) and energy tolerance are shown. In Table 2, * marks are comparative examples showing samples that are outside the scope of this embodiment.

As shown in Table 2, in each of the current-voltage non-linear resistors according to the present embodiment, the varistor voltage (V _{1 mA} ) is 900 V / mm or more, and the non-linearity coefficient (V _{10 kA} / V _{1 mA} ) is 1. It was found that it was smaller than .300 and the energy withstand capacity was larger than 400 J / cc. Further, it was found that the current-voltage non-linear resistor according to the present embodiment has higher resistance than the comparative example, and has excellent non-linear resistance characteristics and energy tolerance.

From the above results, the relative ratio of the average particle size (D50s) of the auxiliary component raw material to the average particle size (D50z) of the zinc oxide raw material is D50s / D50z ≦ 0.60, and the average particle size of the zinc oxide raw material is It is 700 nm or less, and as an auxiliary component raw material, boron is converted to B ₂ O ₃ and contains 0.005 to 0.04 wt%, and silver is converted to Ag ₂ O and contains 0.005 to 0.04 wt%. In a current-voltage non-linear resistor comprising a sintered body obtained by firing a mixture in which the relative ratio of boron to silver satisfies the relationship of 0.125 ≦ B ₂ O ₃ / Ag ₂ O ≦ 1.00. It was found that high resistance can be achieved, and excellent non-linear resistance characteristics and energy withstand capacity can be obtained.

(Example 3)
In Example 3, zinc oxide (ZnO) is the main component and bismuth (Bi), antimony (Sb), manganese (Mn), cobalt (Co), and nickel as subcomponents in the mixture for producing the sintered body. The effect of each content of (Ni) on the characteristics of the current-voltage non-linear resistor will be described.

First, among the subcomponent raw materials of the sintered body used to prepare the sample No. 4 in Example 1, yttrium, boron, silver and aluminum have the same contents, and other subcomponents (Bi ₂ O _3). , Sb ₂ O ₃ , MnO, Co ₂ O ₃ , NiO) were adjusted so as to have the values of sample numbers 25 to 48 shown in Table 3.
Subsequent steps for producing the current-voltage non-linear resistor were the same as in Example 1 described above, and a current-voltage non-linear resistor was obtained.
In each sample, the average particle size (D50t) of all raw materials was 695 nm, the average particle size of zinc oxide (D50z) was 700 nm, and D50s / D50z was 0.50. The condition was controlled. The average particle size (D50t) of all raw materials, the average particle size of zinc oxide (D50z), and the average particle size (D50s) of all subcomponents were measured by the same method as in Example 1.

The varistor voltage (V _{1 mA} ), non-linear resistance characteristics, and energy withstand capacity were evaluated for the obtained current-voltage non-linear resistors of sample numbers 25 to 48. The experimental conditions, experimental methods, and evaluation criteria for evaluating the varistor voltage (V _{1 mA} ), non-linear resistance characteristics, and energy tolerance were the same as the experimental conditions and methods of Example 1 described above.
In each of the above evaluation tests, 10 pieces of each current-voltage non-linear resistor of sample numbers 25 to 48 were prepared, 10 pieces were tested, and the average of them was used for evaluation.

Table 3 shows the composition components (raw material addition amount) of the sub-components of the mixture in the current-voltage non-linear resistors of sample No. 4 (see Table 1), sample numbers 25 to 48, and varistor voltage (V). _1mA ), non-linearity coefficient (V _10kA / V _1mA ) and energy withstand. In Table 3, * marks are comparative examples showing samples that are outside the scope of this embodiment.

As shown in Table 3, in each of the current-voltage non-linear resistors according to the present embodiment, the varistor voltage (V _{1 mA} ) is 900 V / mm or more, and the non-linearity coefficient (V _{10 kA} / V _{1 mA} ) is 1. It was found that it was smaller than .300 and the energy withstand capacity was larger than 400 J / cc. Further, it was found that the current-voltage non-linear resistor according to the present embodiment has higher resistance than the comparative example, and has excellent non-linear resistance characteristics and energy tolerance.

From the above results, zinc oxide is contained as a main component, and Bi ₂ O ₃ is converted into Bi ₂ O ₃ , Sb ₂ O ₃ , Co ₂ O ₃ , MnO, and NiO as sub components, respectively, and Bi ₂ O ₃ is 0.30 to 0.30. 0.80 mol%, Sb ₂ O ₃ 1.50 to 3.50 mol%, MnO 5.00 to 2.00 mol%, Co ₂ O ₃ 0.30 to 1.50 mol%, NiO 1.50 to 1. 3.50 mol%, boron is converted to B ₂ O ₃ and contains 0.005 to 0.04 wt%, silver is converted to Ag ₂ O and contains 0.005 to 0.04 wt%, and silver of boron is contained. Relative ratio to the average particle size (D50s) of the auxiliary component raw material to the average particle size (D50z) of the zinc oxide raw material, satisfying the relationship of 0.125 ≦ B ₂ O ₃ / Ag ₂ O ≦ 1.00. However, in the current-voltage non-linear resistor provided with a sintered body obtained by firing a mixture having D50s / D50z ≦ 0.60 and an average particle size of the zinc oxide raw material of 700 nm or less, the resistance is increased. It was found that excellent non-linear resistance characteristics and energy withstand were obtained.

(Example 4)
In Example 4, the effect of the addition of rare earth elements on the characteristics of the current-voltage non-linear resistor in the mixture for producing the sintered body will be described.

First, among the subcomponents of the sintered body used to prepare the sample number 4 in Example 1, the rare earth element was added to the mixture having the same component composition other than the rare earth element, and the sample number 49 shown in Table 4 was added. -Adjusted to the value of sample number 80, a mixture consisting of a zinc oxide raw material and these auxiliary component raw materials was prepared.
Subsequent steps for producing the current-voltage non-linear resistor were the same as in Example 1 described above, and a current-voltage non-linear resistor was obtained.
In each sample, the average particle size (D50t) of all raw materials was 695 nm, the average particle size of zinc oxide (D50z) was 700 nm, and D50s / D50z was 0.50. The condition was controlled. The average particle size (D50t) of all raw materials, the average particle size of zinc oxide (D50z), and the average particle size (D50s) of all subcomponents were measured by the same method as in Example 1.

The varistor voltage (V _{1 mA} ), non-linear resistance characteristics, and energy withstand capacity were evaluated for the obtained current-voltage non-linear resistors of sample numbers 49 to 80. The experimental conditions, experimental methods, and evaluation criteria for evaluating the varistor voltage (V _{1 mA} ), non-linear resistance characteristics, and energy tolerance were the same as the experimental conditions and methods of Example 1 described above.
In each of the above evaluation tests, 10 pieces of each current-voltage non-linear resistor of sample numbers 49 to 80 were prepared, 10 pieces were tested, and the average of them was used for evaluation.

Table 4 shows the composition components of rare earth elements, the varistor voltage (V _{1 mA} ), and the non-linearity coefficient (V) in the current-voltage non-linear resistors of sample No. 4 (see Table 1) and sample numbers 49 to 80. _{10 kA} / V _{1 mA} ) and energy withstand. In Table 4, * marks are comparative examples showing samples that are outside the scope of this embodiment.

As shown in Table 4, in each of the current-voltage non-linear resistors according to the present embodiment, the varistor voltage (V _{1 mA} ) is 900 V / mm or more, and the non-linearity coefficient (V _{10 kA} / V _{1 mA} ) is high. It was found that it was smaller than 1.300 and the energy withstand capacity was larger than 400 J / cc. Further, it was found that the current-voltage non-linear resistor according to the present embodiment has higher resistance than the comparative example, and has excellent non-linear resistance characteristics and energy tolerance.

From the above results, the relative ratio of the average particle size (D50s) of the auxiliary component raw material to the average particle size (D50z) of the zinc oxide raw material is D50s / D50z ≦ 0.60, and the average particle size of the zinc oxide raw material is It is 700 nm or less, and contains 0.005 to 0.04 wt% of boron as an auxiliary component raw material when converted to B ₂ O ₃ , and 0.005 to 0.04 wt% when converted to Ag ₂ O of silver. , And the relative ratio of boron to silver satisfies the relationship of 0.125 ≦ B ₂ O ₃ / Ag ₂ O ≦ 1.00, and further, as auxiliary component raw materials, thulium (Y), europium (Eu), and elibium (Er). ), thulium (Tm), gadolinium (Gd), dysprosium (Dy), holmium (Ho), using at least one rare earth element R of the ytterbium (Yb), and in terms of _R 2 _{O 3} 0.10 It has been found that a current-voltage non-linear resistor having a sintered body obtained by firing a mixture containing ~ 0.50 mol% can achieve high resistance and can obtain excellent non-linear resistance characteristics and energy withstand. ..

(Example 5)
In Example 5, the effect of the addition of the trivalent element on the characteristics of the current-voltage non-linear resistor in the mixture for producing the sintered pair will be described.

First, among the sintered body components used to prepare sample number 4 in Example 1, a mixture having a similar component composition other than aluminum, which is a trivalent element, is mixed with trivalent elements (aluminum, gallium, indium). ) Was adjusted so as to have the values of sample numbers 81 to 94 shown in Table 5, and a mixture consisting of a zinc oxide raw material and these subcomponent raw materials was prepared.
Subsequent steps for producing the current-voltage non-linear resistor were the same as in Example 1 described above, and a current-voltage non-linear resistor was obtained.
In each sample, the average particle size (D50t) of all raw materials was 695 nm, the average particle size of zinc oxide (D50z) was 700 nm, and D50s / D50z was 0.50. The condition was controlled. The average particle size (D50t) of all raw materials, the average particle size of zinc oxide (D50z), and the average particle size (D50s) of all subcomponents were measured by the same method as in Example 1.

The varistor voltage (V _{1 mA} ) and the non-linear resistance characteristics of the obtained current-voltage non-linear resistors of sample numbers 81 to 94 were evaluated. The experimental conditions, experimental methods, and evaluation criteria for evaluating the varistor voltage (V _{1 mA} ) and non-linearity were the same as the experimental conditions and methods of Example 1 described above. In each of the above evaluation tests, 10 pieces of each current-voltage non-linear resistor of sample numbers 81 to 94 were prepared, 10 pieces were tested, and the average of them was used for evaluation.

Table 5 shows the composition components of the trivalent elements, the varistor voltage (V _{1 mA} ) and the non-linearity coefficient in the current-voltage non-linear resistors of Sample No. 4 (see Table 1), Sample Nos. 81 to 94. V _{10 kA} / V _{1 mA} ) is shown. In Table 5, * marks are comparative examples showing samples that are outside the scope of this embodiment.

As shown in Table 5, in each of the current-voltage non-linear resistors according to the present embodiment, the varistor voltage (V _{1 mA} ) is 900 V / mm or more, and the non-linearity coefficient (V _{10 kA} / V _{1 mA} ) is 1. It was found to be less than .300. Further, it was found that the current-voltage non-linear resistor according to the present embodiment has high resistance and excellent non-linear resistance characteristics as a comparative example.

From the above results, the relative ratio of the average particle size (D50s) of the auxiliary component raw material to the average particle size (D50z) of the zinc oxide raw material is D50s / D50z ≦ 0.60, and the average particle size of the zinc oxide raw material is It is 700 nm or less, and as an auxiliary component raw material, boron is converted to B ₂ O ₃ and contains 0.005 to 0.04 wt%, and silver is converted to Ag ₂ O and contains 0.005 to 0.04 wt%. And, the relative ratio of boron to silver satisfies the relationship of 0.125 ≦ B ₂ O ₃ / Ag ₂ O ≦ 1.00, and as auxiliary component raw materials, aluminum (Al), gallium (Ga), and indium (In). ), Using at least one or more trivalent elements, converted to Al ³⁺ , Ga ³⁺ , and In ³⁺ , respectively, and calcined a mixture containing 0.003 to 0.010 mol%. It was found that the voltage non-linear resistor has high resistance and excellent non-linear resistance characteristics.

(Example 6)
In Example 6, the influence of the 50% fracture strength of the mechanical strength of the sintered body on the energy withstand property characteristics of the current-voltage non-linear resistor will be described.

The mixture was adjusted to have a component composition similar to that of the raw material of the sintered body used to prepare the sample numbers 1, 3, 4, 7, 8 and 10 in Example 1 above.
Subsequent steps for producing the sintered body are the same steps as in Example 1 described above, but there is a difference only in the step of molding the obtained granulated powder by a hydraulic press molding machine, and the diameter is different. A cylindrical molded body having a thickness of 40 mm and a thickness of 40 mm was used to prepare a sintered body.
The six types of sintered bodies produced were designated as sample numbers 95 to 100, respectively, and the mechanical strength of the sintered bodies was measured for them.

Here, as for the mechanical strength of the sintered body, a test piece having a size of 3 × 4 × 38 mm was processed from each sintered body, and the bending strength was measured by a 4-point bending test in accordance with JIS R1604. Further, 10 pieces of test pieces were processed from each sintered body, and the average value of their 50% fracture strength was taken as the mechanical strength of each sintered body.

Further, in the evaluation of the energy withstand capacity, the test was carried out by increasing the energy of an impulse current of 4/10 μs from 400 J / cc until the energy was destroyed by about 50 J / cc. During the application, it was cooled to room temperature. The larger the minimum energy (destruction energy) until destruction, the better the energy withstand. In the energy tolerance test, 10 pieces of each sintered body were produced, tests were performed on each of the 10 pieces, and the average value of the obtained fracture energy values was evaluated as "fracture average energy".

Table 6 shows the 50% fracture strength (MPa) and the fracture average energy (μ: J / cc) in the energy tolerance test in the sintered bodies of sample numbers 95 to 100. In Table 5, * marks are comparative examples showing samples that are outside the scope of this embodiment.

As shown in Table 6, it was found that when the 50% fracture strength of the mechanical strength of the sintered body was 140 MPa or more, the average energy until fracture was 700 J / cc or more, and an excellent energy withstand capacity could be obtained.

From the above results, the energy withstand capacity can be improved by setting the 50% fracture strength of the mechanical strength of the sintered body to 140 MPa or more. That is, it was found that the current-voltage non-linear resistor energy withstand capacity can be further increased by mounting a sintered body having excellent 50% fracture strength as a component of the current-voltage non-linear resistor. ..

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, as well as in the scope of the invention described in the claims and the equivalent scope thereof.

10 ... current-voltage non-linear resistor, 20 ... sintered body, 30 ... insulating layer, 40 ... electrode

Claims (11)

Current-voltage non-voltage for firing a mixture containing zinc oxide as the main component and at least bismuth oxide, antimony oxide, manganese oxide, cobalt oxide, nickel oxide, rare earth element R, trivalent elements, boron and silver as the secondary component raw materials. This is a method for manufacturing linear resistors.
The relative ratio of the average particle size (D50s) of the auxiliary component raw material to the average particle size (D50z) of the zinc oxide in the mixture is D50s / D50z ≦ 0.60, and the average particle size of the zinc oxide (D50z). ) Is 700 nm or less,
The mixture contains 0.005 to 0.04 wt% of the boron in terms of B ₂ O ₃ , 0.005 to 0.04 wt% of the silver in terms of Ag ₂ O, and the boron. A method for producing a current-voltage non-linear resistor in which the relative ratio of silver to silver satisfies the relationship of 0.125 ≦ B ₂ O ₃ / Ag ₂ O ≦ 1.00. The subcomponent raw materials are Bi ₂ O ₃ , Sb ₂ O ₃ , Co ₂ O ₃ , MnO, and Ni O, respectively, and Bi ₂ O ₃ is 0.30 to 0.80 mol% and Sb ₂ O ₃ is 1. .50 to 3.50 mol%, MnO 0.50 to 2.00 mol%, Co ₂ O ₃ 0.30 to 1.50 mol%, NiO 1.50 to 3.50 mol%. A method for manufacturing a current-voltage non-linear resistor. The rare earth element R is at least one of yttrium (Y), europium (Eu), erybium (Er), thulium (Tm), gadolinium (Gd), disprodium (Dy), holmium (Ho), and itteribium (Yb). The method for producing a current-voltage non-linear resistor according to claim 1 or 2, which is a rare earth element of the above and contains 0.10 to 0.50 mol% in terms of R ₂ O ₃ . The trivalent element contains at least one of aluminum (Al), gallium (Ga), and indium (In), and contains 0.003 to 0.010 mol% in terms of Al ³⁺ , Ga ³⁺ , and In ³⁺ , respectively. The method for manufacturing a current-voltage non-linear resistor according to any one of claims 1 to 3.
The current-voltage non-linear resistor according to any one of claims 1 to 4, wherein in the mixture, the average particle size (D50t) of all the raw materials including the zinc oxide and the auxiliary component raw materials is 750 nm or less. Production method. Baking made by firing a mixture containing zinc oxide as the main component raw material and at least bismuth oxide, antimony oxide, manganese oxide, cobalt oxide, nickel oxide, rare earth element R, trivalent element, boron and silver as auxiliary component raw materials. A current-voltage non-linear resistor with a sinter
The relative ratio of the average particle size (D50s) of the auxiliary component raw material to the average particle size (D50z) of the zinc oxide in the mixture is D50s / D50z ≦ 0.60, and the average particle size of the zinc oxide (D50z). ) Is 700 nm or less,
The sintered body contains 0.005 to 0.04 wt% of boron in terms of B ₂ O ₃ , 0.005 to 0.04 wt% of silver in terms of Ag ₂ O, and boron. The relative ratio to silver satisfies the relationship of 0.125 ≦ B ₂ O ₃ / Ag ₂ O ≦ 1.00.

A current-voltage non-linear resistor having a varistor voltage (V _{1 mA} ) of 900 V / mm or more, which is a voltage when a current of a commercial frequency of _{1 mA} is applied. The current-voltage non-linear resistor according to claim 6, wherein 50% fracture strength of the mechanical strength of the sintered body is 140 MPa or more. Current-voltage non-voltage consisting of a mixture containing zinc oxide as the main component and at least bismuth oxide, antimony oxide, manganese oxide, cobalt oxide, nickel oxide, rare earth element R, trivalent elements, boron and silver as the secondary component raw materials. A material for linear resistors
The relative ratio of the average particle size (D50s) of the auxiliary component raw material to the average particle size (D50z) of the zinc oxide in the mixture is D50s / D50z ≦ 0.60, and the average particle size of the zinc oxide (D50z). ) Is 700 nm or less,
The mixture contains 0.005 to 0.04 wt% of the boron in terms of B ₂ O ₃ , 0.005 to 0.04 wt% of the silver in terms of Ag ₂ O, and the boron. A material for a current-voltage non-linear resistor in which the relative ratio of silver to silver satisfies the relationship of 0.125 ≦ B ₂ O ₃ / Ag ₂ O ≦ 1.00. The subcomponent raw materials are Bi ₂ O ₃ , Sb ₂ O ₃ , Co ₂ O ₃ , MnO, and Ni O, respectively, and Bi ₂ O ₃ is 0.30 to 0.80 mol% and Sb ₂ O ₃ is 1. .50 to 3.50 mol%, MnO 0.50 to 2.00 mol%, Co ₂ O ₃ 0.30 to 1.50 mol%, NiO 1.50 to 3.50 mol%. Material for current-voltage non-linear resistors.
The rare earth element R is at least one of yttrium (Y), europium (Eu), erybium (Er), thulium (Tm), gadolinium (Gd), disprodium (Dy), holmium (Ho), and itteribium (Yb). of a rare earth _element, a current according to claim 8 or 9 comprising 0.10～0.50Mol% in terms of R 2 _{O 3} - voltage non-body material.
The trivalent element contains at least one of aluminum (Al), gallium (Ga), and indium (In), and contains 0.003 to 0.010 mol% in terms of Al ³⁺ , Ga ³⁺ , and In ³⁺ , respectively. The material for a current-voltage non-linear resistor according to any one of claims 8 to 10.

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