JPS5994401A - Method of producing voltage nonlinear 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 Field of Industrial Application The present invention is a method for manufacturing a voltage nonlinear resistor, which comprises adding electrodes to both sides of a sintered body made by adding glass frit to a zinc oxide varistor composition and firing it at a high temperature. It is related to.

Conventional configuration and drawbacks Conventionally, voltage nonlinear resistors were mainly made of silicon carbide.
So-called SiC varistors, which are hardened with a porcelain binder, have been widely used, but recently, varistors with zinc oxide as the main component,
A so-called zinc oxide varistor, which uses a sintered body to which metal oxides such as Bi2O3 and Co2o3 are added, mixed, molded, and fired, has been produced and put into practical use.

The voltage-current characteristics of this type of voltage nonlinear resistor (hereinafter referred to as a varistor) are generally expressed by the following equation.

I - (V/C) where ■ is a current, ■ is a voltage, and C1α is a constant. The characteristics of the varistor can be expressed by two constants, C and α. C is the voltage when the current is 1 ampere, and generally corresponds to the resistance value of a fixed resistor, and it is desirable that the voltage nonlinearity index α is as large as possible for a small varistor.

The present inventors replaced C with a current of 10 μA, 100 μA,
1 rrA, -Old voltage at 2100A v10pA
,"100uA ・"1mA -...,■10oA
are using.

The growth of zinc oxide varistor is extremely large at 40 to 1o○.
It has remarkable effects on voltage stabilization and surge voltage suppression, and is widely used to protect electronic equipment. Recently, there has been an active movement to use zinc oxide varistors in high-voltage, high-energy fields such as lightning arresters. However, zinc oxide varistors used in lightning arresters are constantly applied with high voltage and are susceptible to high energy such as lightning surges. Since there is no shortage of absorption, the shape of the zinc oxide varistor element becomes large. The shape of a zinc oxide varistor element used for the protection of electronic equipment is usually 3ffi to 14πm in diameter and 0.5mm in thickness. fy-2mW, whereas the shape of the zinc oxide varistor element used in lightning arresters etc. is 30171ffl~sown in diameter and 30cm~ thick.
He is 50 years old.

Since the zinc oxide varistors used in lightning arresters and the like are large in size, the required performance cannot be met using normal manufacturing methods for small devices.

Among the required performances, the charging life characteristics, pulse life characteristics, and discharge withstand characteristics are particularly important. As a measure to improve the charging life characteristics of conventional small zinc oxide varistor elements, (1) After applying glass to a sintered body, heat treatment is performed at 500° C. to 850° C. to diffuse the glass.

(2) Boric anhydride (B2O3) r Barium oxide (Ba
Glassy additives such as O) are added and fired. (3)
Bismuth boronate glass or lead borosilicate glass is added and fired. (4) Bismuth oxide.

Methods such as adding glass made of boric anhydride, cobalt oxide, and silver oxide and firing are employed.

However, when the above method is applied to a large device, (1)
In this method, since the element is thick, the glass cannot be fully diffused into the element, making it impossible to obtain stable performance. In the method (2), gelation of the slurry of the raw material mixture occurs, so a calcination step is required as a countermeasure against this, and furthermore, moldability is poor and cracks occur inside the element. Furthermore, the discharge withstand capacity and pulse life deteriorate.

Although method (3) has no problems in the manufacturing process, the life of the applied voltage is slightly poor, and the discharge withstand capacity and pulse life are also poor.

Although the method (4) does not have any problems in the manufacturing process, it does have problems such as insufficient energization life and weak discharge withstand and pulse life.

Purpose of the Invention In view of the above-mentioned drawbacks, the present invention seeks to provide a method for manufacturing a voltage nonlinear resistor in which even a large-sized zinc oxide varistor element has uncertain charge life characteristics, pulse life characteristics, and discharge withstand capacity. be.

Structure of the Invention In order to achieve this object, as a method for manufacturing the voltage nonlinear resistor of the present invention, the constituent materials and amount of glass frit to be added to the zinc oxide varistor composition were studied, and especially high voltage,
This is a zinc oxide varistor element used in the high energy field with improved charging life characteristics, pulse life characteristics, and discharge withstand capacity. Specifically, bismuth oxide (Bi203) 40-90
Silica (SIO2) 5-25 wt%, boric anhydride (B203) 1°-30 wt%, silver oxide (Aq2)
0) 5-30 wt%, antimony oxide (Sb203)
1000' of glass composition consisting of 2-30 wt%
After melting at C~1250°C and cooling, 0.01~5 parts by weight of finely pulverized glass frit is added to 100 parts by weight of the zinc oxide varistor composition, mixed and molded, and the molded body is heated to 850°C~ The sintered body is calcined at 950°C, a mixed paste of bismuth oxide, silica, and antimony oxide is applied to the side surface of the calcined body, and an electrode is provided on the sintered body obtained by firing at 1000°C to 1400°C. The present invention provides a method for manufacturing a voltage nonlinear resistor.

Description of examples Hereinafter, the present invention will be explained according to examples.

First, bismuth oxide (Bi203) 40-90 wt.

Silica (SiO2) 5-25wt%, boric anhydride (B2
0310-30wt%, silver oxide (Ag2O) 6-30
wt person.

Contains 2 to 30 wt% of antimony oxide (Sb203).

Mix, put the mixture in a platinum crucible, and heat at 1000℃~12
After melting at 50'C, it is poured into water, rapidly cooled, and pulverized in a pot mill to make a glass frit.

On the other hand, zinc oxide (ZnO) 85~9'8.5 mo
e%.

Bismuth oxide (B1203) 0.01-5 mol, oxidized.

Cobalt (C0203) 0.01~5m01%, manganese oxide (MnO2) 0+01~5m01%, antimodium oxide, (Sb2o3) 0°02~10m01%, oxidized OA (Cr 203.'0.01~5mrich, Silica (S102) 0.02-10mol%, nickel oxide (Nio) o, o2-10mol%.

Aluminum oxide (A1203) 0.001~ノ,05
Formulated with molchi (hereinafter referred to as barista composition)
Add 0.01 to 5 parts by weight of the glass frit to 100 parts by weight of this varistor composition, mix,
The molded body is calcined at 850°C to 950°C, and bismuth oxide (Bi203), silica (5zO2), and antimony oxide (Sb203) are added to the side surface of the calcined body.
Apply a side high resistance agent consisting of
Electrodes are attached to both sides of the cylindrical sintered body obtained by firing at 0°C by metal spraying.

A comparison of the characteristics of the inventive example and the conventional example made in this way is made using a sintered body with a diameter of 33mm and a thickness of 30mm, as shown in Figures 1 and 2.
As shown in Fig. 3. FIG. 1 shows the charging life characteristics, FIG. 2 shows the pulse life characteristics, and FIG. 3 shows the discharge endurance characteristics. In the energization life test, the sample is placed in a constant temperature bath at 130°C, and an AC voltage with a peak voltage equivalent to the voltage of 95 cm of 1 mA of the sample is applied between the electrodes of the sample, and the increase in leakage current is determined. I looked into it. The pulse life characteristics are determined by applying a current waveform of 8x2 to the sample.
Pulses of 0 μs and a current peak value of 5000 A were repeatedly applied to examine the rate of change in vlmA of the sample. On the other hand, in the discharge capacity test, a pulse current with a current waveform of 4 x 10 μs was applied twice to test the sample ■1! In Figure 0, which shows the rate of change in nA, A shows the characteristics of the product of the present invention, and A shows the characteristics of the conventional product.

The above results show that the product of the present invention has bismuth oxide (Bi2O3)5
0 wt%, silica (5102) 10 vvt% y
Boric anhydride (B203) 20Wt, silver oxide (Ag2O
) 20wt%, antimony oxide (Sb2o3) 15wt
% was melted at 1200'C, rapidly cooled, and the finely ground glass frit was mixed into a varistor composition (ZnO95, 49.5m
01%, B12030.6 mol%, Co
2030a5 mo7%.

MnO20.5 moe%, 5b2031.0 mo1
%, cr2o30.6mo7%, 5in20.5mo
7%, NiO1, OrnolJ%.

A12030.005 mai1%) per 100 parts by weight. , 1 part by weight was added, mixed and molded, the molded body was calcined at 900°C, and bismuth oxide was added to the side surface of the calcined body.

A high-resistance agent made of silica and antimony oxide was coated on the side surface and baked at 1000°C. In addition, the conventional product is B
12035 B -4wt%, 5in212.5
wt%.

B20312.5 wt%, Coo 8.3
wt%, Ag2O8.3wt%, and other conditions are the same as the products of the present invention.

If the amount of glass frit added is less than 0.01 parts by weight, the effect of improving the charging life characteristics is lost, while if it exceeds 5 parts by weight, the discharge withstand capacity deteriorates. Furthermore, if Bi2O3 in the glass frit is less than 40 wt %, vitrification becomes difficult, and if it exceeds 90 wt %, the voltage nonlinearity index α of the device becomes poor. Next, if SiO2 is less than 5 wt%, the charged life of the element will be poor, and if it exceeds 25 wt%, the discharge withstand capacity will be poor. Furthermore, when B2O3 is less than 10 wt%, the voltage nonlinearity index α is poor υ, and when it exceeds 30 wt%, the discharge withstand capacity is poor. And Ag2O is 5wt
If it is less than 30wt1%, the charging life characteristics will be poor, and if it exceeds 30wt1%, the discharge withstand capacity will be poor. Also, 5b203 is 2
If it is less than 30 wt%, the pulse life characteristics will deteriorate.
Vitrification became difficult when the temperature exceeded .

Effects of the Invention As described above, the present invention can greatly improve the charge life characteristics, pulse life characteristics, and discharge withstand characteristics of large-sized zinc oxide varistor elements, and has great practical effects.

[Brief explanation of drawings]

Figure 1 is a diagram showing a comparison between the inventive product and the conventional product in terms of energization life characteristics, Figure 2 is a diagram showing the comparison between the inventive product and the conventional product in terms of pulse life characteristics, and Figure 3 is the discharge withstand characteristic. FIG. 2 is a diagram showing a comparison between a product of the present invention and a conventional product. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure = R Shiguan (hrs) Figure 2 → f71 times (times) ゛Figure 83

Claims (2)

[Claims] (1) Bismuth oxide (Bi203) 40-90wt%
. Silica (S 102 ) 5-25 wt%, boric anhydride (B203) 10-30 wt%, silver oxide (Ag20)
5-30wt%. A glass composition consisting of 2 to 30 wt % of antimony oxide (Sb203) is melted at 1000'C to 1250 C, then cooled, and the finely ground glass frit is added in an amount of 0.01 to 30 parts by weight per 100 parts by weight of the zinc oxide varistor composition. Add 5 parts by weight, mix and mold, and heat the molded product at 850°C to 96°C.
Calcinate at 0℃, apply a mixed paste of bismuth oxide, silica, and antimony oxide to the side of the calcined body, and
A method for manufacturing a voltage nonlinear resistor, comprising providing an electrode on a sintered body obtained by firing at a temperature of 1400°C to 1400°C. (2) Change the blending composition of the zinc oxide varistor composition to zinc oxide (
ZnO) s s ~98.5 mo1%, bismuth oxide (B1203) 0.01-5 mQ1%, cobalt oxide (C02o3) 0.01-5 mo1%, manganese oxide (MnO2) 0.01-5 m01%', oxidation Antimony (Sb2Q3) 0.02-10mo7%, chromium oxide (Cr2o3) 0.01-5m0l, silica (S1
02) 0-02~10mo1%, nickel oxide/L/
(NiO) 0.02~10rnol%, aluminum oxide (A1203) 0.001~0.05m0
Method I for manufacturing a voltage nonlinear resistor according to claim 1, where the voltage is set to 1%.