JPH0438802A - Manufacture of zinc oxide type arrester element - Google Patents

Abstract

PURPOSE:To improve the adhesion to an element assembly, environmental resistance, and voltage applied life characteristics under a high-humidity condition of the title arrester element by forming a measuring-face high resistance layer of a pulverized body prepared by pulverizing a mixture of bismuth, antimony, silicon, and zinc in a specific composition ratio into a specific size after the mixture is calcined. CONSTITUTION:A pulverized body for a measuring-face high resistance layer is prepared by pulverizing a mixture containing bismuth, antimony, silicon, and zinc in a ratio of 1-4 mole %, 3-10 % mole %, 15-36 mole %, and 50-80 mole %, respectively, equivalent to their oxides Bi2O3, Sb2O3, SiO2, and ZnO, with the sum of the oxides being 100 mole %, after the mixture is calcined. The size of the pulverized body is set at minus 30 mesh and plus 300 mesh. This zinc oxide type arrester element is manufactured by forming the measuring- face high resistance layer by the conventional method by using the pulverized body thus prepared.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a voltage non-linear resistor mainly composed of zinc oxide, on which a side high resistance layer is formed that contributes to improved environmental resistance.
This article relates to a method for manufacturing zinc oxide type lightning arrester elements used in various lightning arresters, surge absorbers, etc.

[Prior Art] Conventionally, the main component is zinc oxide, contains at least bismuth oxide, and further contains antimony oxide, cobalt oxide, manganese oxide, silicon oxide, etc., which promote the development of voltage nonlinearity.
Resistors containing other trace additives exhibit excellent voltage nonlinearity and are widely used in various lightning arresters and surge absorbers, and are used in an extremely wide range of applications, including stable power supply and equipment protection.

Since this element is usually used gapless,
It is required to have excellent stability against normal voltage application (electrification life characteristics) and also to have excellent surge current absorption ability. The lifetime of the device bulk has been improved by controlling the additives and the crystal phase of bismuth oxide.

In recent years, devices are becoming more LB type and more complex with m functions, and the number of cases in which this element is used in combination with other equipment is increasing, and the element is not necessarily used only under a certain clean environment. This is no longer the case. For example, under high humidity,
It is used in special gases (highly insulating gases such as SFs), insulating oil, etc.

However, in these atmospheres, despite the stability of the bulk characteristics of this element, an increase in leakage current due to deterioration (lower resistance) near the side surface and external flash shorting occur when surge current is applied. Problems arise during use.

That's why, in order to protect the sides of this voltage non-linear resistor and improve its surge absorption ability, a high-resistance polycrystalline layer (mainly composed of three crystal phases: zinc silicate, zinc antimonate, and bismuth oxide) is placed on the side surface. This method has been conventionally practiced (for example, Japanese Patent Publication No. 53-21516 and Japanese Unexamined Patent Application Publication No. 52-49491), and this method has achieved certain results such as improved impulse resistance. However, it has become clear that when used in adverse environments such as high humidity, it does not exhibit sufficient functionality such as a reduction in surface resistance.

[Invention tries to solve:ll! [Problem] The environmental resistance of the side high resistance layer is related to the dispersion state of zinc silicate and spinel phase within the high resistance layer, and these crystal particles are uniformly distributed and combine with each other to form the internal The structure to protect is important. However, in a structure where the dispersion is biased, for example, where only zinc silicate forms a continuous layer and spinel phase particles are sparsely scattered near the continuous layer, it is difficult to resist charging under high humidity. There are drawbacks such as insufficient current stability.

The present invention has been made to solve the above-mentioned problems, particularly in improving the charging life characteristics under adverse environments. The object of the present invention is to provide a method for manufacturing a lightning arrester element.

[Means for solving the problem] In order to improve the environmental resistance of the element, it is important to form a uniform distribution of the zinc silicate and spinel phases, which are the constituent phases of the side high resistance layer ( (Refer to the specification of Japanese Patent Application No. 1-184772).

The present invention uses bismuth, antimony, silicon, and zinc as materials for the side high resistance layer of a zinc oxide type lightning arrester element, respectively.
Calcining a mixture with a composition ratio of 1 to 4 mol%, 3 to 10 mol%, 15 to 36 mol%, and 50 to 80 mol%, making the total 100 mol% in terms of ZnO. After that, a side high-resistance layer is formed using powder that has been pulverized to a size that passes through a mesh Th (according to JIS regulations, hereinafter the same) sieve and does not pass through a g lk 330 sieve. The present invention relates to a method of manufacturing a featured zinc oxide type lightning arrester element.

[Function] By using the above-mentioned materials, unlike conventionally formed high-resistance layers, the crystals of zinc silicate and spinel phase are uniformly distributed without being biased, and the adhesion with the element body is improved. This improves environmental resistance and significantly improves the charging life characteristics under high humidity.

U Embodiment In the present invention, bismuth, antimony, silicon, and zinc are each oxide (Bi2O3
, 5bxO3, 5I02, ZnO) l: Converted to Bi
20x 1-4 mol%, preferably 1-3 mol%, 5b
xO3 3-10 mol%, preferably 4-8 mol%, 51
02 15-36 mol 9fi, preferably 15-30 mol%, Zn0 50-80 mol%, preferably 60-80
A powder is used which is obtained by calcining and pulverizing a mixture in which the components are contained in a proportion of mol % and the total amount is 100 mol %.

Bi2O3 is a component to promote sintering, and if its proportion is less than 1 mol%, sintering between particles will not proceed sufficiently, resulting in a large number of voids, and if it exceeds 4 mol%, a rapid reaction will occur, resulting in high side resistance. The layers become uneven.

5b203 is a component for forming high-resistance particles (Zn7Sb20+2), and if its proportion is less than 3 mol%, the shrinkage rate of the entire high-resistance layer becomes small and cracks occur.
If it exceeds 10 mol%, large Zny 5b2Or on the surface
2 particles are generated, and the high resistance layer becomes uneven.

5I02 is a component for forming a high-resistance Z n 2 S i 04 phase, and if its proportion is less than 15 mol%, it will result in a highly uneven high-resistance layer, and if it exceeds 36 mol%, the adhesion with the element body will deteriorate. become bad.

ZnO is a component for adjusting the shrinkage rate of the high-resistance layer, and if its proportion is less than 50 mol%, the shrinkage rate will be small and the adhesion with the element will be poor, and if it exceeds 80 mol%, unreacted ZnO will The remaining high resistance layer on the side surface is made to have a low resistance.

The mixture is pulverized by, for example, a dry ball mill.
It can be obtained by conventional methods such as mixing.

The calcination of the mixture prevents rapid reactions and locally uneven reactions from occurring during the main calcination, and also improves the matching of the shrinkage rate with the element body, thereby causing the constituent crystal phases to mix with each other. This is a process to improve the adhesion with the element body. This calcination is carried out, for example, by placing the mixture in an aluminum crucible with a lid and heating it at 900 to 1150° C. for 1 to 5 hours.

The calcined mixture is pulverized using, for example, a mill, so that the size of the particles of the powder obtained by pulverization is such that it passes through a 30 mesh sieve and does not pass through a N11L330 sieve. Preferably mesh No. 1
This is done so that the size is such that it passes through a No. 00 sieve but does not pass through an N11L330 sieve. If the particle size of the resulting powder is too large to pass through the mesh 30, when the paste for side high resistance layer is applied to the side surface of the element body, the particles will be coarse and uneven, and after the main firing, Not only does the thickness of the side high-resistance layer become uneven, but also cracks occur, resulting in poor moisture resistance. On the contrary, mesh breeding 330
Grinding until the material passes through is not only inefficient in material production, but also causes the generation of fine particles, which intensifies the reaction between the particles again, causing separation of the constituent crystal phases and generation of voids between the elementary bodies. A problem arises in that the adhesion deteriorates.

There are no particular limitations on the pulverization conditions, and any conditions may be used as long as they can produce powder having a size within the above range.

The desired zinc oxide type lightning arrester element is manufactured by forming a side surface high resistance layer using the material for the side surface high resistance layer thus obtained by a conventional method.

That is, for example, etocel,
Add a binder such as butyl calpitol or n-butyl acetate at 150 to 200 g per 100 g of side high resistance layer material.
It is added at a ratio of 30 to 701 g/cJ to form a paste, and applied to an element body containing zinc oxide and small amounts of bismuth oxide, antimony oxide, cobalt oxide, manganese oxide, silicon oxide, etc., at a ratio of, for example, 30 to 701 g/cJ. , 1150-12
By baking at 50℃ for 2 to 10 hours, the thickness of 5
A zinc oxide type arrester element having a lateral high resistance layer of 0 to 140- is replaced.

In addition, if you want to further improve the impulse withstand capacity as devices become smaller, you can increase the thickness of the side high-resistance layer,
A glass layer may also be formed on the element.

As described above, by the manufacturing method of the present invention, the distribution of crystal grains of the polycrystalline body is uniform, the adhesion between the element body and the side high resistance layer is improved, and the environment resistance is excellent, and the charging of electricity under high humidity is improved. Zinc oxide type lightning arrester element with significantly improved life characteristics has been replaced.

The present invention will be described in more detail below based on Examples.

Example 1 and Comparative Example 1 First, voltage nonlinear resistors (element bodies) having the compositions shown in Table 1 were fabricated using a predetermined ceramic process.

Following Table 1, six sets of 10 types of mixtures (mixture numbers 1 to 10) with the mixing ratios shown in Table 2 were prepared, and after stirring each mixture, they were placed in an aluminum crucible with a lid and heated to 1110℃.
The mixture was calcined in a batch furnace for 1 hour. Next, each set of samples is determined to have a size that passes through a mesh klO sieve and does not pass through a mesh 30 sieve (group A), mesh number, and a size that passes a 30 sieve and does not pass through a mesh
Size that does not pass through a 100 sieve (group B), mesh No. 100 sieves and mesh) k 2
A size that does not pass through a sieve of 00 (set of 0), a size that passes through a sieve of 200 meshes, and mesh No. Size that does not pass through the 280 sieve (group D), mesh demon 280
The 6 types of sizes shown in Table 3 are crushed to a size that passes through the sieve but does not pass through the mesh 330 sieve (group E) or to a size that passes through the mesh 330 sieve (group F). A total of 60 types of samples were obtained.

[Each sample shown in Table 3 below (Samples 4B to 4E, 5B to 5E,
68~BE, 7B~7E, 8B~8E, 9B~
Example 1 uses 9E, and Comparative Example 1 uses other samples.) 100g and Ethocel 4
110 g of 0g1 butyl calpitol and 30 g of n-butyl acetate were mixed to form a paste.

After phosphorizing the above element at 950°C for 4 hours, each paste was applied to the side surface of the element at a rate of 50 g/cj, and this was further fired at 1200°C for 5 hours in a batch furnace. A side high resistance layer with a thickness of approximately 100 degrees was formed on the side surface of the element body.

Thereafter, electrodes were provided using M metallicon, and the electrical characteristics of the device were investigated as follows.

That is, to check humidity resistance, the humidity was 80% RH.

Leakage of the element when a voltage of 0.6 times the voltage (vl, A) when a current of 11^ is passed across the element in an atmosphere at a temperature of 80°C is continuously applied (charge rate 06) Changes in current over time were measured. The results are shown in Figure 3. In Figure 3, the vertical axis is A
It shows the change in the leakage current of the C resistance and is normalized by t (voltage application time) - 〇.

Among the 60 types of samples, IA, IB, Ic,
10. LE.

IFl 2^, 2B, 2C, 2D, 2E, 2F,
3A, 3B, 30. 3D.

3E, 3F, 4A, 4F, 5A, 5F, 6
A, 6F, 7A, 7F, 8A.

8F, 9A, 9F, 10^, IOB,
The device using the sample of 10C, 100, IOE% IOF shows pattern ■, 4B.

4C, 4D, 4E, 5B, 5C, 5D, 5E
, 6B, 6C, 8D, and BH samples exhibit pattern n, and 7B, 7C.

7D, 7E, 8B, 8C, 80, 8E, 9B,
Devices using samples 9C, 9D, and 9H are pattern I.
showed that.

In this way, the way the AC resistance leakage current changes is classified into three types of patterns. The elements exhibiting the pattern (2) are stable, and the elements exhibiting the pattern (2) in which the leakage current tends to increase are unstable. Elements exhibiting the tendency of pattern I have a small leakage current and are particularly advantageous in practical terms.

Next, we attempted to observe the cross section of the side surface in order to examine the reason why the change in leakage current differs depending on the composition and particle size distribution of the side surface high-resistance layer material.

FIG. 1 is a cross-sectional view schematically showing the structure of a side high resistance layer of a typical element showing changes in pattern I. Discrimination of each particle is EP14A%Xl? Based on analysis methods such as D. As shown in Figure 1, the white part of zinc silicate (Z
nzS to4) [Zinc antimonate (Zny 5b20r) constituting the 21 particles and the spinel phase in the shaded area
It was confirmed that (1) was uniformly mixed therein, and that it had good affinity with the part of the element body whose living body was zinc oxide (3). The main part is a side high resistance layer with a thickness of about 10 DI.

On the other hand, FIG. 2 is a cross-sectional view schematically showing the structure of a side high resistance layer of a typical element showing a change in pattern (2). Second
As shown in the figure, zinc silicate (a) and zinc antimonate (
1) is the side high resistance layer (part (C), thickness approximately 100ρ)
It is separated into two crystalline regions inside. Furthermore, it can be seen that the spinel layer forms the outermost layer intermittently with respect to the continuous zinc silicate layer. (The Bl part is an elemental body whose living body is zinc oxide.

Note that in FIGS. 1 and 2, black portions (4) indicate vacancies where crystals are missing. These holes (black parts) were often seen in the elements showing the pattern (■). In other words, it can be said that the device exhibiting the pattern (2) also has poor adhesion between the side high resistance layer and the element body.

In addition, in FIGS. 1 and 2, bismuth oxide is omitted because it is small in quantity and to avoid complication of the drawings.

From these results, it can be seen that the device characteristics are more stable even in a bad environment under high humidity when the crystal phases constituting the side surface high resistance layer are mixed with each other and have a close structure.

Next, we will add considerations from the formulation aspect.

5b203.5I02 undergoes the following reaction with ZnO.

7ZnO+5b20x +02 Zn7Sbz
O+z2ZnO+ 5102
Znz 510a, that is, 5b203 is A mole,
The number C of moles of ZnO that completely reacts with a mixture of 8 moles of 5I02 is C-AX7+BX2. As shown in Table 4, among the mixtures:
Mixtures 4 to 1O are formulations close to this condition.

Therefore, by calcining these samples and reacting them in advance, it is possible to prevent sudden reactions and locally uneven reactions during the main firing, and it is also possible to better match the shrinkage rate with the element body. . As a result, the constituent crystal phases coexist with each other, improving adhesion to the element body. The reason why the sample using mixture 1o shows unstable characteristics is that this mixture contains too much ZnO and unreacted ZnO remains, and this part has low resistance, so the high resistance layer on the side surface This is because the insulation properties deteriorate.

[Blank below] Fang 1 Xi 3 Zinc oxide [Effects of the invention] As described above, according to the present invention, bismuth, antimony, silicon, and zinc are mixed in a specific ratio as a side high-resistance layer material, calcined, and pulverized. Since the crystals are used in the lateral high-resistance layer, the presence of crystals can be uniformly distributed, and the adhesion with the element body can be improved, thereby producing a zinc oxide type lightning arrester element with excellent environmental resistance. be able to.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view schematically showing the fine structure of a side high resistance layer of an element according to the present invention showing pattern I in FIG. 3;
Figure 2 is a cross-sectional view schematically showing the fine structure of the high-resistance layer on the side of the device showing the pattern ■ in Figure 3, and Figure 3 is a graph showing the pattern of electrical characteristics obtained by differences in the high-resistance layer on the side. be. (Drawing code) (1): Zinc antimonate (2), zinc silicate (3), zinc oxide/

Claims (1)

[Claims] (1) Bismuth, antimony, silicon, and zinc are used as materials for the side high-resistance layer of a zinc oxide type lightning arrester element, respectively, in terms of Bi_2O_3, Sb_2O_3, SiO_2, and ZnO, 1 to 4 mol%, 3 to 10 mol%, 15
~38 mol% and 50-80 mol% with a total of 1
After calcining a mixture with a composition ratio of 0.00 mol%, JIS mesh No. Passes through 30 sieves and N
o. A method for manufacturing a zinc oxide type lightning arrester element, characterized in that a side high resistance layer is formed using powder crushed to a size that does not pass through a No. 330 sieve.