JPS5994402A - 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 its problems Traditionally, 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 SiC varistors have been made with zinc oxide as the main component.
131203. A so-called zinc oxide varistor, which uses a sintered body to which a metal oxide such as CO2O3 is 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/(J") where I is current, ■ is voltage, and C2α is a constant.The characteristics of a varistor can be expressed by two constants, C and α.C is the value when the current is 1 ampere. It is a voltage, which generally corresponds to the resistance value of a fixed resistor, and it is desirable for a varistor to have a voltage nonlinearity index α as large as possible.

The present inventors replaced C with a current of 10 μ8, 100 pA,
1 mA, -.

Voltage at 100A■104A, 1004A I v
1mAI■ ..., vl. . I am using A.

The α of the oxide varistor is extremely large, ranging from 40 to 100.
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, the zinc oxide varistor used in lightning arresters and the like is constantly applied with high voltage and must absorb high energy such as lightning surges, so the shape of the zinc oxide varistor element becomes large. The shape of zinc oxide varistor elements used to protect electronic equipment is usually 3 mm to 14 mm in diameter.
While the thickness is 0.5 to 2M, the shape of the zinc oxide varistor element used in lightning arresters etc. is 30mm-80mm in diameter.
Me, the thickness is 30wa to 50M.

In this way, zinc oxide varistors used in lightning arresters etc. have a large shape, so the required performance cannot be met using normal manufacturing methods for small devices.Among the required performances, especially the charged life characteristics and discharge withstand characteristics. is important. As a measure to improve the energized life characteristics of conventional small zinc oxide varistor elements, (1) After applying glass to the sintered body,
The glass is diffused by heat treatment at 0°C. (2) Anhydrous d
('B203).

Adding glassy additives such as barium oxide (BaO),
Fire. (3) Bismuth borosilicate glass or lead borosilicate glass is added and fired.

(4) A method has been adopted in which a glass made of bismuth oxide, boric anhydride, cobalt oxide, or silver oxide is added and fired. However, when the above method is applied to a large element, the glass is not completely diffused into the element due to method (1) because the element is large, and stable performance cannot be obtained.

In the method (2), since gelation of the slurry of the raw material mixture occurs, a calcination step is necessary as a countermeasure against this, and the moldability is poor and cracks occur inside the element.

Furthermore, the discharge withstand capacity deteriorates. Method (3) does not have any problems in the manufacturing process, but the energizing life is a little short and the discharge withstand capacity is also low. Method (4) also has no problems in the manufacturing process, but it has problems such as an insufficient charging life and a weak discharge capacity.

OBJECTS OF THE INVENTION In view of the above-mentioned drawbacks, the present invention seeks to provide a method for manufacturing a voltage non-linear resistor that has excellent charge life characteristics and discharge withstand capacity even when using a large zinc oxide varistor element.

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 and discharge withstand capacity. Specifically, bismuth oxide (Bi203) 40 to 90 Wt, perilla strength (
Sio2) 5-25wt%, boric anhydride (B2O2)1
0~S.

A glass composition consisting of 5 to 30 wt% of silver oxide (Ag2O) was melted at 1000 °C to 1250 °C, cooled, and finely pulverized. Provided is a method for manufacturing a voltage nonlinear resistor, characterized in that an electrode is provided on a sintered body obtained by adding 0.01 to 6 parts by weight, mixing, molding, and firing at 10,001 to 1,400°C. It is.

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

First, bismuth oxide (Bi2O2) 40~eoWt,
Silica (StO2) 5-25wt%, boric anhydride (
B2O2) 10~3wt%, silver oxide (8q20) 5~
Blend and mix 30 wt %, put the mixture in a platinum crucible, melt at 1000 ° C to 1250 ° C, and then pour it into water,
It is rapidly cooled and pulverized in a pot mill to make glass frit.

On the other hand, zinc oxide (ZnO) 85-98.5 mo1%
.

Bismuth oxide (B1203) 0.01-5 mot%
, cobalt oxide (CO203) α01-5 mo1%,
Manganese oxide (MnO2) o, Q1-5m0L%, antimony oxide (Sb203) 0.02-10 mo1%,
Chromium oxide (Cr 203) 0.01~5 znoZ
%, silica (5102) 0.02-10 mot%, oxidation-'') Kel (Nip) 0.02-10 mot%, aluminum oxide (A t 203) 0.001-o, os
moz% (hereinafter referred to as a varistor composition), and based on 100 parts by weight of this varistor composition,
Adding 0.01 to 5 parts by weight of the glass frit, mixing and molding, and calcining the molded product at 850°C to 950°C,
A cylindrical sintered body is obtained by coating the sides of the calcined body with a side high resistance agent consisting of bismuth oxide (B12O3), silica (5102) r antimony oxide (Sb203), and firing at 1000°C to 140Q°C. Electrodes are attached to both sides by metal spraying.

A comparison of the characteristics of the inventive example and the conventional example made in this manner is shown in FIGS. 1 and 2 using a sintered body having a diameter of 33 mm and a thickness of 30 ff++1. FIG. 1 shows the charging life characteristics, and FIG. 2 shows the discharge endurance characteristics. In the energized life test, the sample is placed in a constant temperature bath at 130℃, and the sample's ■1rnA is
An AC voltage having a peak voltage corresponding to 95% of the voltage was applied, and the increase in leakage current was investigated. On the other hand, in the discharge withstand test, the rate of change of 1 mA of the sample was examined when a pulse current with a current waveform of 4 x 10 μs was applied twice. In the figure, A indicates the characteristics of the product of the present invention, and A indicates the characteristics of the conventional product.

The above results show that the product of the present invention has bismuth oxide (B1203) 5
0wt%, Si+) Force (Sin2) 10wt%,
Anhydrous porcelain (B203) 20wt%p Silver oxide (Ag2
O) 20wt% was melted at 1000°C and then rapidly cooled,
The finely ground glass frit was made into a varistor composition wJ (Zn0
95.496mot%, Bi O005m0L%,
CO2O33 0.5mot%, MnO20.6rnot%, 5b2
031. .

mo7%, Cr2O30,5mO4%, 5in20.5
mot%.

1 inch 101.0 mot%, At2030. ○05mo,
/=%) 0.1 part by weight is added to 10° parts by weight, mixed and molded, the tR shape is calcined at 900°C, and the side surface of the calcined body is coated with bismuth oxide, silica, and antimony oxide. A high resistance agent of 1 μm per surface was coated on each surface and fired at 1200°C. The conventional product is B 120368.4
wt%, SiO1'2.5wt%, B20312.5
vvt%.

It is a glass composition containing 8.3 wt% of Coo and 3 wt% of Ag2O8, and the pond conditions are the same as those of the product of the present invention.

If the amount of glass frit added is less than 0.01 parts by weight, the effect of improving the electrification life characteristics is lost, while if it exceeds 5 parts by weight, the discharge withstand capacity deteriorates. Further, if B12O3 in the glass frit is less than 4 Q wt %, vitrification becomes difficult, and if it exceeds 90 wt %, the voltage nonlinearity index a of the device deteriorates. Next, S z 02 is 5wt%
If it is less than 25 wt %, the life of the device will be shortened, and if it exceeds 25 wt %, the discharge capacity will be deteriorated. Furthermore, B2O3 is 1
Below 0wt%, the voltage non-linearity index α becomes worse at 9.3o.
When it exceeds wt %, the discharge withstand capacity deteriorates. and,
If Ag2O is less than 5wt%, the charging life characteristics will be poor.
When the weight exceeds 30 wt, the discharge withstand capacity deteriorates.

Effects of the Invention As described above, the present invention can greatly improve the charging life characteristics and discharge withstand capacity of large zinc oxide varistor elements, and its practical effects are outstanding.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a comparison between a product of the present invention and a conventional product in charge life characteristics, and FIG. 2 is a diagram showing a comparison between a product of the present invention and a conventional product in terms of discharge withstand characteristics.

Claims (2)

[Claims] (1) Bismuth oxide (B12O3) 40 to 90 wt%. Silica (S IO2) 5-25 wt%, boric anhydride (
B2O2) 10~30wt%, silver oxide (Aq2o) 5~
A glass composition consisting of 30 wt% 5x was heated at 1000°C to 12
The glass frit, which is melted at 50°C, cooled and finely ground, is added in an amount of 0.01 to 100 parts by weight of the zinc oxide varistor composition.
Add 5M parts, mix and mold, and heat to 1000℃~1400℃
A method for manufacturing a voltage nonlinear resistor, which comprises providing an electrode on a sintered body obtained by firing at °C. (2) Change the blending composition of the zinc oxide varistor composition to zinc oxide (
Z: nO) 85-9 B, 6rnot%, bismuth oxide (Bi203) 0.01-5rQot%, cobalt oxide (C02o3) 0.01-5m0t%, 1-77gan (MnO2) o, o1-s rnot %, oxidation 7
7f%7(Sb203)O102~10m0L%, chromium oxide (Cr203)0.01~5mO2%, chestnut power (
S102) 0.02-10 mo, l-%, Nichel oxide (NiO) 0.02-10 mot%, aluminum oxide (At2o3) 0.001-0.06 mo
A method for manufacturing a voltage nonlinear resistor according to claim 1, in which the voltage is reduced by t%.