JPS61112301A - Electrode material for voltage 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] Industrial applications The present invention relates to an electrode material used in a voltage nonlinear resistor.

Conventional configurations and their problems Voltage nonlinear resistors (hereinafter referred to as varistors) are widely used in surge absorption elements, voltage stabilization elements, lightning arresters, etc. Conventionally, silicon carbide has been used for these applications. Varistors, silicon varistors, etc. have been provided. However, these varistors have drawbacks such as a small voltage nonlinearity coefficient α, the inability to adjust the characteristics arbitrarily, and a large shape. It was naturally restricted.

Recently, zinc oxide (
An oxide sintered body varistor has been developed which is made of ZnO (ZnO) as the main component, to which trace amounts of several metal oxides are added, mixed, molded, and fired. This varistor has an excellent voltage nonlinearity coefficient, so its use is expanding, but there are still many deficiencies in the electrical circuits of highly developed communication equipment.

Generally, the voltage nonlinearity of a varistor is evaluated by the values of the voltage nonlinearity coefficients α and Vi expressed by the following equations.

I/i = (V/Vi)α
...... ■Here, ■ is the current flowing through the varistor, ■
is the applied voltage, and Vi is the voltage at a constant current i ampere, which is usually called the rising voltage.

α and vi are practically important constants in indicating the electrical characteristics of the varistor. α indicates how the voltage of the electric circuit in which the varistor is inserted is controlled, and the larger α is, the better the voltage rise is, and the larger α is preferable except for special applications. ``30'' or more is preferable. Vi is determined depending on the usable voltage, and is adjusted to a predetermined value depending on each product.

By the way, if we consider the conditions of use in the electrical circuit of communication equipment, the increase in leakage current with respect to the constantly applied voltage is small, and the limiting voltage ratio characteristic [generally, the voltage between the terminals of the varistor when 1 mA flows, V + mA, and the current of other values. A varistor with excellent voltage nonlinearity in a large current region is required.

However, as the glass frit component in the electrode material, Bi2O5 has a weight range of 40 to 90%, and B2O3 has a weight range of 10 to 30%.
Conventional method 1 using bismuth borosilicate glass which is oxidized by 5 to 25 weight SiO2! When a pole material is used in a ZnO-based varistor, the current situation is that the characteristic deterioration of the varistor voltage during the life of energization is large and the limiting voltage ratio is not satisfactory.

OBJECTS OF THE INVENTION An object of the present invention is to provide an electrode material that can improve the characteristics of a ZnO-based varistor.

Structure of the Invention The electrode material for a voltage non-linear resistor of the present invention is a zinc borosilicate glass containing 35 to 70 wt. 100 parts by weight of bis oxide 1 F40~
90% by weight, silica 5~25wt, boric anhydride 10~
100% bismuth borosilicate glass made by blending 30% by weight
Using a glass frit containing ~500 layers, Zn
It is characterized by improved characteristics of O-based varistors.

Description of examples The present invention will be explained in detail below.

First, ZnO is 96mol/L'S, Bi2O is 0.6molQ, CoO is 0.5molN16,M
nO2 at 0.9 mo/L/%, 5b20. 0.9Mo#
4. 0.6 moles of NiO)ve4 and 0.5 moles of Cr2O5 were weighed out and mixed in a Beaufre Mill. The thus obtained mixed mixture was dried and calcined at 700 to 950° C. (this calcination may be omitted), a binder (PVAS water solution) was added, and pressure molded into a disk. After that, 1100～
Sintered body obtained by firing at 1300°C (diameter 10fl)
After polishing to a thickness of 0.8 yna, a silver electrode with a diameter of 8 mm was baked.

The silver electrode used here was a zinc borosilicate glass powder [Table 1 below shows the composition ratio of the zinc borosilicate glass used] 1
00 parts by weight of bismuth borosilicate glass powder [Table 2 below shows the composition ratio of the bismuth borosilicate glass used]
A glass powder prepared by blending 100 to 500 parts by weight of NuL with a predetermined ratio of 10 to 100 parts by weight, and a glass powder prepared by dissolving ethyl cellulose in Buti-rho-vitol/L/(30 parts by weight).
(regret) with Ag powder (60% by weight),
Make it into a paste.

Tables 1, 2 and 3 below show the electrical properties of the sintered bodies thus obtained.

Margin below Table 3 This third table was calculated from the results of measuring voltage-current characteristics from 1 μA to 15 A, and the non-linear index between 0.1 mA and ImA is 0.1α1. Q mA , V+
mA/m, current value 15AK > Kel V +5A and V
+mAC' ratio V+sA/V+fIIA (limiting voltage ratio) and rate of change of V+oμ in energized life characteristics △V/V
It is expressed as IQIJA (regret).

The charging life characteristics are V+mA in a constant temperature oven kept at 80℃.
After applying the DC voltage of 904 for 500 hours, return to room temperature and V+oμA (V+
oμA) was measured to calculate the rate of change, and the characteristics were evaluated using this.

As shown in Table 3, the varistors using samples No. 1 to 25 of the present invention have much better energized life characteristics than the sump/L'NO.26 that does not contain zinc borosilicate glass. At the same time, the limiting voltage characteristics have also been improved.
This satisfies the characteristics required for varistors used in electrical circuits of communication equipment.

The effective blending range of glass components is
Zinc borosilicate glass containing 35-70 weight range in the form of '100
Bismuth oxide (Bi203) 40-90 parts by weight
The weight range is 100 to 500 parts by weight of bismuth borosilicate glass formed by combining 5 to 25 weight % of silica (S +02) and 10 to 30 weight % of boric anhydride (B203).

If glass outside these ranges or zinc borosilicate glass with a different zinc distribution amount is used, 0.1α1
．． OmA less than 30, V 15A/V ImA 14
If the varistor exceeds 5, the characteristic deterioration of the varistor voltage during the energized life becomes large; However, if the Bi2O3 content in the bismuth borosilicate glass is less than 40% by weight, vitrification becomes difficult, and if it exceeds 90% by weight, the voltage nonlinearity index α of the device deteriorates. Next, if S+02 is less than 5 weight ratios, the life of the violet will be poor, and if it exceeds 25 weight ratios, the discharge withstand capacity will be poor. Furthermore, B20. If it is less than 10%, the voltage nonlinearity index α will be poor, and if it exceeds 30%, the discharge withstand capacity will be poor.

The electrode material of the present invention is printed and baked as described in the detailed description of the invention
By configuring an nO-based varistor, it is possible to obtain a varistor that exhibits excellent voltage non-linear characteristics from a small current region to a large current region, and has an extremely excellent current life characteristic suitable for electrical circuits of communication equipment. be.

Claims (1)

[Claims] 1. As a glass component of the electrode material of a voltage non-linear resistor mainly composed of ZnO, 40 to 90 parts of bismuth oxide is added to 100 parts by weight of zinc borosilicate glass containing 35 to 70 parts by weight of zinc in the form of ZnO. % by weight, 5-25% by weight of silica,
An electrode material for a voltage nonlinear resistor using a glass frit containing 100 to 500 parts by weight of bismuth borosilicate glass containing 10 to 30 parts by weight of boric anhydride.