JPS60192302A - 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 [Technical Field of the Invention] The present invention relates to a method for manufacturing a voltage non-plane wire resistor whose main component is curved lead oxide and whose sintered body itself has non-linear resistance characteristics.

Blue [Technical background and problems of the invention] Voltage nonlinear resistors are generally called varistors, and their excellent nonlinear voltage-current characteristics are used to stabilize voltages or absorb surges. Widely used in lightning arresters and surge absorbers. A typical example is the recently developed curved lead varistor. The main component is lead oxide, to which small amounts of oxides such as bismane, antimony, cobalt, manganese, and chromium are added, mixed and granulated.
After being molded, it is fired at a high temperature in air, and electrodes are attached to the sintered body. Its non-linear resistance properties are very good, and the sintered body consists of a grain boundary layer formed by the zinc oxide component and the surrounding additives. Although these ZnO-based varistors have many advantages such as being able to arbitrarily adjust the current-voltage characteristics, they have the following drawbacks when used as power surge arresters. Ta. That is, in the conventional ZnO-based voltage nonlinear resistor, when an impact current is applied, the difference in the rate of change in voltage in the positive direction and the negative direction is large, and the rate of change in the negative direction is particularly large.

In addition, there was a large change in characteristics in the small current region under constant voltage application. In order to eliminate these drawbacks of ZnO-based nonlinear resistors, it is common to add several oxides or various glass components to the basic composition of ZnO and various oxides. A method is being taken. However, if the characteristics are improved by adding oxides, the rate of change when an impact current is applied and the difference in the rate of change in the positive direction and negative direction can be reduced, but the characteristics change in the small current region due to constant voltage application. When the characteristics are improved by using various glass components, the change in characteristics in the small current range due to constant energization is small, but there is no effect on the shock current characteristics, and it is not sufficient to be used as a power surge arrester. Ta.

[Purpose of the invention]

The present invention has been made to solve these drawbacks, and it is possible to reduce the difference in the rate of change of voltage in the positive direction and the negative direction when an impact current is applied, to reduce the rate of change in voltage, and to constantly apply current. An object of the present invention is to provide a method for manufacturing a voltage nonlinear resistor that reduces characteristic changes in the small current region.

[Summary of the invention]

In order to achieve such an object, the present invention uses ZnO as a main component and contains Bi, Co, Sb, Mu, and as subcomponents.
Bl each Ni! O,, Co20. , 5b20.
, MnO, 0.05 to 3 mol% in terms of NiO, A
l, B, Ag, 81 respectively, he, O,, B, 103
．． Ag2O, sio, in conversion, '1: ; f: Reso FL.

0.0005-002 mol%, 0.005-0.1 mol%, 0. ('101~005 mol%, 0005~01
A method for manufacturing a voltage nonlinear resistor by mixing, molding, and firing a composition containing mol%, characterized in that 0.001 to 10 mol% of a lead oxide component is used as a starting material in the form of metallic zinc. .

[Embodiments of the invention]

The present invention will be explained in detail below using examples.

B i, O8, Co20. , MnO, each 0.5
Mok%, 8 btOs, NrO each at 1
．． 0 mol%, A40g + 810g, Ag, o
, S + O, are 0.005 and 0.02, respectively.
0.005 mol%, 0.02 mol%, and 0.02 mol% of metallic zinc.
ZnO was added in an amount of 0.001 to 10 mol %, and the remainder was ZnO. These ingredients were accurately weighed.

Water, dispersant,
Put into a dispersion/mixing device together with binder and lubricant and disperse/disperse.
Mixed. Next, the mixture slurry is granulated using a spray dryer so that the average particle size is, for example, 120 microns. This powder was pressed into a disk having a diameter of 55 mm and a thickness of 30 mm. In order to remove the added dispersant, binder, and lubricant in advance, the molded product was baked at 500° C. in air to obtain a molded product.

These molded bodies were sintered at 1200°C in an air atmosphere to obtain a sintered body, both sides were polished parallel to each other to a thickness of 20 mm, and then A and L were sprayed on the polished surfaces to attach the electrodes. A non-linear resistor was obtained. The impact current characteristics and constant charging characteristics of this voltage nonlinear resistor are compared with those of the conventional example and are shown in Table 1.
It uses nO raw material.

Table 1 shows the impact current characteristics and constant charging characteristics in terms of the rate of change in the positive direction and the rate of change in the negative direction of 1 ml. It can be seen from Table 1 that the varistors obtained by the manufacturing method of the present invention are significantly superior to conventional ones. The shock current characteristics are obtained by looking at the rate of change in both the positive and negative directions of the V1mA value when a surge current of 8xwμ is applied 100 times, and is stable as a surge absorption element, which is the main use of varistors. This is a study of gender. The constant charging characteristics were obtained by examining the rate of change in VtmA after continuous application of DClmA for 500 hours at 120°C. It can be seen that conventional varistors deteriorate significantly at high temperatures.

The voltage nonlinear resistor obtained by the manufacturing method of the present invention has an extremely small difference in the rate of change in the positive direction and the negative direction, that is, the polarity characteristic. This is very important in terms of maintaining symmetrical current-voltage characteristics, and these life characteristics and stability guarantee high reliability as an element. This is important from a practical standpoint. Although oxides were used as raw materials other than metal zinc in the above embodiments, it goes without saying that the raw materials are not necessarily limited to oxides as long as they become oxides during firing. For example, silica oxide, nitrate, etc. may be used.

The most effective amount of metallic zinc to be added is in the range of 0,001 to 10 mol %, as is clear from the impact current characteristics shown in the attached diagram. In the range of less than 0,001 mol % or more than 10 mol %, the rate of change in the negative direction becomes negative, and the stability is comparable to that of conventional materials.

〔Effect of the invention〕

As described above, according to the present invention, metal zinc is used as a starting material within the above-mentioned composition range in a method for manufacturing a voltage nonlinear resistor whose main component is zinc oxide and whose sintered body itself has voltage nonlinear characteristics. By containing 0.001 to 10 mol %, it is possible to provide a method for manufacturing a voltage nonlinear resistor having very good polar characteristics and highly reliable characteristics.

[Brief explanation of the drawing]

The figure is a curve diagram showing the impact current characteristics.

Claims (1)

[Claims] The main component is ZnO, and the subcomponents include Bi, Co,
8b. Bl each of Mn and N+! Os, Co□Os, S
b, O,, MnO. 005 to 3 mol% in terms of NiO, Al, B, Ag,
That's 81; it, u, o3. B, 0. , A
g, 0, 5io21 = conversion rate 0.0005 each
~002 mol%, 0005~0.1 mol%, 0001~
0.05 mol%, 0.001 to 10% of the zinc oxide component as a starting material in a composition containing 0.005 to 0.1 mol%
A method for manufacturing a voltage nonlinear resistor using mol% in the form of metallic zinc.