JPS6254404A - Manufacture of non-linear resistor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for manufacturing a nonlinear resistor whose sintered body itself has voltage nonlinearity and is used in an overvoltage protection device in an electrical system.

[Technical background and problems of the invention]

2. Description of the Related Art In electrical systems, overvoltage protection devices such as surge absorbers and avoiders are used to protect electrical systems and electrical equipment by removing overvoltages superimposed on normal voltages.

This overvoltage protection device uses a non-linear resistor that exhibits almost insulating properties at normal voltage and has a relatively low resistance value when overvoltage is applied.

A non-linear resistor is made by pressing a material made of zinc oxide (zno) mixed with a metal oxide, molding it, and firing it.

ZnO-based non-linear resistors have steep non-linear characteristics in the small current range and have a sharp rise up to the large current range, so it is better to use the conventionally used SiC-based non-linear resistors. It is possible to make an overvoltage protection device that is better than the overvoltage protection device.

When this ZnO-based nonlinear resistor is used in a high humidity condition, the resistance value of the side surface of the nonlinear resistor decreases. In other words, there is a problem that the nonlinear index α is significantly impaired, and conventionally, zinc antimonate (Zn, S
By providing a patented anti-layer characterized by b, 01 □), not only the moisture resistance was improved but also the prevention of lead surface flashing was attempted.

However, the conventional non-linear resistor is, for example,
], as shown in Publication No. 284, a method of forming a high resistance layer on the side surface is to apply a substance in the form of ■ sb, o, and s.
b2'o, is reacted with ZnO inside the sintered body to form "Z
Method of forming n7Sbz-0□2.

■ Zn in the form of the final composition from the beginning, 5b2-
A method of attaching a substance containing 0.2 to the side surface.

It has been known. However, the former method (1) does not fully react during firing, resulting in 5b20. However, in the latter method (2), the final composition of the reaction is coated, so adhesion is poor.

[Purpose of the invention]

The present invention was made in view of the above drawbacks, and by improving the adhesion between the high-resistance layer and the element body, it is possible to obtain a non-linear resistor that has excellent moisture resistance and can improve impulse resistance. An object of the present invention is to provide a method for manufacturing a nonlinear resistor.

[Summary of the invention]

In order to achieve such an object, according to the present invention, a substance containing Zn, Bi, 5bffO1, or Zr+, B13Sby is added to the side surface of a compact body mainly composed of zinc oxide or a compact body obtained by calcining a compact in advance. O14 and 5in
2. Tie,, Fe2O.

After applying a substance containing one material selected from the group consisting of This is to obtain a resistor.

[Embodiments of the invention]

Examples of the present invention will be described in detail below.

(Example 1) First, bismuth oxide (B
xio3)-cobalt oxide (Co□03), manganese oxide (MnO), and chromium oxide (Cr, o3) at 0.
5 mol%, antimony oxide (s'bzoi), and nickel oxide (NiO) powders were added in the range of 1.0 mol% each, and in order to thoroughly mix these raw material powders, water, 2 dispersants, a binder, It was mixed together with lubricant in a mixing device.

This mixture slurry was granulated using a spray dryer to, for example, have an average particle size of 120 microns, and the powder was pressed to form a disk having a diameter of 50 mm and a thickness of 30 mm. After firing in air at 500°C to remove the added dispersant, binder, and lubricant, a slurry for forming a high-resistance layer prepared in advance was applied to the calcined body at 1020°C using a spray gun.

The slurry for forming the high resistance layer was prepared as follows. Zinc oxide (ZnO) 40 mol%, bisman oxide (
Bi,,0. ) 30 mol%, antimony oxide (Sb2
03) Zn2B1. produced by baking powder mixed at 30 mol% at 650 to 950°C. Sb,
Pure water was added to O, at a weight ratio of 1:1 to make a suitable slurry.

At this time, the strength of the coating film is increased by adding about 0.1% by weight of a binder such as polyvinyl alcohol.

After the slurry prepared in this manner was applied to the element body, the element body was fired at a temperature of 1200° C. in an air atmosphere. Thereafter, both surfaces of the sintered element were polished in parallel to a thickness of 20 mm, and electrodes were formed on both surfaces by thermal spraying of aluminum to obtain a nonlinear resistor.

The properties of the nonlinear resistor thus obtained are shown in FIGS. 1 and 2.

Figure 1 shows that when a nonlinear resistor is left in a constant temperature chamber with a humidity of 90% or more and a temperature of 90°C for a long time,
The voltage v1°μA required to cause a current of A to flow was measured, and the rate of change ΔVtoμA with respect to the initial value was calculated and illustrated.

Further, FIG. 2 shows the convergence rate when an impulse current with a waveform of 4×10 microseconds is applied.

In Figures 1 and 2, solid line A indicates the conventional Zn7-3b
The broken line B shows the characteristics of a non-linear resistor in which a high resistance layer was formed by applying a material containing 20t*,
The characteristics of a non-linear resistor in which a high resistance layer is formed by coating a substance containing SbxOt* are shown.

As is clear from FIGS. 1 and 2, the Zn2B of the present invention
A non-linear resistor in which a substance containing i3Sb3014 is applied to an element body and then sintered to form a high-resistance layer has superior moisture resistance and improved impulse resistance compared to conventional non-linear resistors.

The reason why such excellent characteristics are obtained in the present invention is considered as follows. That is, Zn, Bi, Sb,
-0□ is Bi2O which reacts with ZnO inside the element body to form Zr+, 5b20x□ in the reaction shown below, and is liberated at that time.

Since Zn promotes the reaction with ZnO, the adhesion of the formed high-resistance layer (Zn, sb2':h z ) increases. Furthermore, since Zn2-B13Sb,0,4 is a very active substance, one reaction is not completed and it does not remain as it is.

2Zn2Bi, Sb, 01. + I 7ZnO→
3Zn, 5b20□2+3[+1203 According to the above examples, the nonlinear resistor manufactured according to the present invention has excellent moisture resistance and impulse withstand characteristics, and significantly improves the stability of the nonlinear resistor against humidity and impulse current. This is important from a practical standpoint, as it guarantees extremely high reliability when the non-linear resistor is used in a power surge arrester or the like.

(Example 2) In the same manner as in Example 1, an additive was added so that the sintered body itself had voltage nonlinearity. A preliminarily prepared high-resistance layer forming slurry was applied using a spray gun to a preliminarily calcined molded body containing zinc IV chloride as a main component.

The above slurry for forming a high resistance layer was prepared as follows. Zinc oxide (ZnO) 40 mol%, bisman oxide (B
L20J) 30 mol%, antimony oxide (Sb20.
) Zn, 13i3SbJO produced by firing a powder mixed at 30 mol% at 650 to 950°C
Pure water was added to 50 mol % of silicon oxide (Sin) and 50 mol % of silicon oxide (Sin) at a weight ratio of 1:1 to make a suitable slurry. At this time, the strength of the coating film is increased by adding about 0.1% by weight of a binder such as vinyl alcohol. After the slurry prepared in this manner was applied to the element body, the element body was fired at a temperature of 1200° C. in an air atmosphere.

Thereafter, both surfaces of the sintered element were polished in parallel to a thickness of 20 mm, and electrodes were formed on both surfaces by thermal spraying of aluminum to obtain a nonlinear resistor.

The characteristics of the nonlinear resistor thus obtained are shown in FIGS. 3 and 4.

Figure 3 shows that when a non-linear resistor is left in a constant temperature bath at a humidity of 90% or more and a temperature of 9°C for a long time, the non-linear resistor has a 10μ
The voltage V ioμA required to cause a current of A to flow was measured, and the rate of change Δv1°μA with respect to the initial value was calculated and illustrated.

Further, FIG. 4 shows the convergence rate when an impulse current with a waveform of 4×10 microseconds is applied.

In Figures 3 and 4, solid line A indicates the conventional Zn2-5i
The characteristics of a non-linear resistor in which a high resistance layer was formed by coating a substance containing O4 and Zn7.5b20□2, and the broken line B shows the properties of a non-linear resistor formed by coating a substance containing Zn, B13Sb, 0.4 and 5un2 of the present invention. The characteristics of the non-linear resistor in which a high-resistance layer is formed are shown below.

As is clear from FIGS. 3 and 4, the Zn of the present invention,
A non-linear resistor in which a material containing B13Sb3014 and Sin is coated on an element body and then sintered to form a high-resistance layer has superior moisture resistance and impulse resistance compared to conventional non-linear resistors. improves.

The reason why such excellent characteristics are obtained in the present invention is considered as follows. That is, Zn2B1. Sb, -
014 reacts with ZnO inside the element body in the reaction shown below to form Zn7Sb, 0.014. , and Bi2O was liberated at that time.

The high resistance layer (zn7Sb20□2 and Zn25in4) was formed to promote the reaction between SiO□ and ZnO.
adhesion increases. Furthermore, since Zn2Bi3Sb, 014 is a very active substance, it does not react completely and does not remain as it is.

■ 2Zn2Bi1Sb304. +17ZnO-+3Z
n, Sb, 01□+3Bi, 03■ 5jO2+2zn
O→zn2SiO9 According to the above examples, the nonlinear resistor manufactured according to the present invention has excellent moisture resistance and impulse withstand characteristics, and significantly improves the stability of the nonlinear resistor against humidity and impulse current. , this means that
When a nonlinear resistor is used in a power surge arrester or the like, it guarantees extremely high reliability, and is important from a practical standpoint.

(Example 3) In the same manner as in Example 1, an element body made of zinc oxide as a main component, to which an additive such that the sintered body itself has voltage nonlinearity, was pre-calcined. The prepared slurry for forming a high resistance layer was applied using a spray gun.

The above slurry for forming a high resistance layer was prepared as follows. Zinc oxide (ZnO) 40 mol%, bisma' oxide/
(B12O3) 30 mo/L/%, antimony oxide (
Sb20. ) 650-9 powder mixed at 30 mol%
Zn2B1. produced by firing at 50°C. ,
Sb, oxidized with 01450 mol%, titanium (Ti
Pure water was added to 50 mol% of O2) at a weight ratio of 1:1 to make a suitable slurry. At this time, the strength of the coating film is increased by adding about 0.1 weight (&%) of a binder such as polyvinyl alcohol. After applying the slurry prepared in this way to the element body, 120 in air atmosphere
It was fired at a temperature of 0°C.

Thereafter, both sides of the sintered element were ground parallel to each other to a thickness of 20 mm, and then electrodes were formed on both sides by thermal spraying of alumina 11 to obtain a nonlinear resistor.

The characteristics of the nonlinear resistor thus obtained are shown in FIGS. 5 and 6.

Figure 5 shows that when a non-linear resistor is left in a constant temperature bath at a temperature of 90°C and a humidity of 90% or more, the non-linear resistor changes to lOμ.
The voltage v required to flow a current of A, 0 μA, was measured, and the rate of change ΔV+oμA with respect to the initial value was calculated and illustrated.

Moreover, FIG. 6 shows the convergence rate when an impulse current with a waveform of 4×10 microseconds is applied.

In Figs. 5 and 6, solid line A indicates the conventional Zn2-3i
The broken line B shows the characteristics of a non-linear resistor in which a high resistance layer was formed by applying a material containing O4 and Zn7Sb201□. The characteristics of a non-linear resistor formed with a high resistance layer coated with a material containing TiO2 and TiO2 are shown.

As is clear from FIGS. 5 and 6, the Zn2B of the present invention
The nonlinear resistor manufactured by coating a material containing i3Sb, 014, and Tio2 on an element body and then sintering it to form a high-resistance layer has better moisture resistance than conventional nonlinear resistors, and is also impulse-resistant. Tolerance is improved.

The reason why such excellent characteristics are obtained in the present invention is considered as follows. That is, Zn2B1.5b3-01
4 reacts with ZnO inside the cord body to form Zr in the reaction shown below.
1v Sbz 0,2 was formed, and Bi2O was liberated at that time.

The formed high resistance layer (Zn, 5b20., and Zn2Tio4) promotes the reaction between TiO2 and ZnO.
adhesion increases. Also Zn213i, Sb, O
,, are very active substances, so they do not undergo a complete reaction and do not remain as they are.

■ 2Zn2I3i, 5b30, 4+17ZnO→3
Zn7Sb20.2÷3BizO3■ Tie2+ 2
ZnO-+Zn, TiO4 According to the above examples, the non-linear resistor manufactured according to the present invention has excellent moisture resistance and impulse single-field characteristics, and significantly improves the stability of the non-linear resistor against humidity and impulse current. This guarantees extremely high reliability when the nonlinear resistor is used in a power evacuator or the like, and is important from a practical standpoint.

(Example 4) In the same manner as in Example 2, an element body made of zinc oxide as a single component and pre-calcined as a molded body to which an additive such that the sintered body itself has voltage non-linearity was added. A slurry for forming a high resistance layer prepared in advance was applied using a spray gun.

The above slurry for forming a high resistance layer was prepared as follows. Zinc oxide (ZnO) 40 mol%, bisman oxide (B
], 20. ) 30 MoJv%, antimony oxide (sb
2o,) 3゜mol% mixed powder at 650~950℃
Zn2Bi3Sb30 produced by firing with
．． 450 mol% and iron oxide (Fe201) 50 mol%,
Pure water was added to the slurry at a ratio of 1:1 to make a suitable slurry. At this time, add 0.0% of a binder such as polyvinyl alcohol.
By adding about 2 parts by weight, the strength of the coating film increases. After the slurry prepared in this manner was applied to the element body, the rope body was fired at a temperature of 1200° C. in an air atmosphere.

Thereafter, both surfaces of the sintered element were polished in parallel to a thickness of 20 mm, and electrodes were formed on both surfaces by thermal spraying of aluminum to obtain a nonlinear resistor.

The characteristics of the nonlinear resistor thus obtained are shown in FIGS. 7 and 8.

Figure 7 shows that when a non-linear resistor is left in a constant temperature bath at a humidity of 90% or more and a temperature of 90°C for a long time,
The voltage V required to cause a current of A to flow. Measure μA and change rate ΔV from the initial value. μA is calculated and illustrated.

Moreover, FIG. 8 shows the confluence rate when an impulse current with a waveform of 4×10 microseconds is applied.

In Figures 7 and 8, solid line A indicates the conventional Zn2-5i
The broken line B shows the characteristics of a non-linear resistor in which a high resistance layer was formed by coating a substance containing O4 and Zn7Sb201□. The characteristics of the non-linear resistor formed with layers are shown.

As is clear from FIGS. 7 and 8, the Zn2B of the present invention
A non-linear resistor in which a substance containing 1,5b3014 and Fe2O is coated on an element body and then sintered to form a high-resistance layer has superior moisture resistance and impulse resistance compared to conventional non-linear resistors. improves.

The reason why such excellent characteristics are obtained in the present invention is considered as follows. i.e. ZnzBliSb, -01
4 reacts with ZnO inside the element body to form Zn in the reaction shown below.
, Sb, 0□2 was formed, and Bi was liberated at that time,
O.

The formed high resistance layer (Zn, Sb, 01□ and ZnFe2
0. ) adhesion increases. Also, Zn2B1. Sb,
Since 014 is a very active substance, it does not react completely and does not remain as it is.

(1) 2ZnzBi3Sb, O□, +17ZnO→
3Zn, 5b20□2+3Bi20゜■ Fe2O, +
ZnO−+ Zn, Fe, 04 According to the above example,
The nonlinear resistor manufactured according to the present invention has excellent moisture resistance and impulse withstand characteristics, and significantly improves the stability of the nonlinear resistor against humidity and impulse current. In the example described above, oxide was used as the raw material, but any material can be used as long as it is sintered to become an oxide. For example, water oxides, carbonates,
The same effect can be obtained even with oxalate or the like. Also,
In addition to the additives shown in the examples, other components may be added for the purpose of improving the characteristics of the nonlinear resistor.

Further, in the examples of the non-exploding invention, the high-resistance layer-forming substance was applied to the calcined element body, but the same effect was observed even when it was applied to the molded element body.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to provide a method for manufacturing a nonlinear resistor that can obtain a highly reliable nonlinear resistor that has excellent moisture resistance and impulse resistance.

[Brief explanation of the drawing]

1 and 2 are diagrams showing moisture resistance characteristics and impulse resistance characteristics diagrams for explaining the effects of Example 1 of the present invention,
3 and 4 are diagrams showing moisture resistance characteristics and impulse resistance characteristics diagrams for explaining the effects of Example 2 of the present invention,
5 and 6 are diagrams showing moisture resistance characteristics and impulse ejection resistance characteristics diagrams, respectively, for explaining the effects of Example 3 of the present invention, and FIGS. FIG. 2 is a diagram showing moisture resistance characteristics and an impulse resistance characteristic diagram for explaining the effect. Representative Patent Attorney Noriyuki Nori Yudo Hirofumi Mitsumata High-temperature lawsuit is on the rise 1st figure 102030! 05060708090100in/
Marres Densei Nao (KA) Figure 2 Blasphemy - Na (Chisho Figure 3: 4”k & 5m! I'Q Figure 6 102030 !050607080 QO100 Impulse Konnao Kakakuchi (/<A)

Claims (1)

[Scope of Claims] 1) A side surface of a molded body mainly composed of zinc oxide or a pre-calcined molded body to which an additive is added so that the sintered body itself has voltage nonlinearity. Zn_2Bi_3Sb
A method for manufacturing a non-linear resistor, comprising applying a substance containing _3O_1_4 and then sintering it to form a high-resistance layer on the side surface of the sintered body. 2) The substance further includes SiO_2, TiO_2, Fe_
2. The method of manufacturing a nonlinear resistor according to claim 1, further comprising one material selected from the group consisting of 2O_3.