JPS62102502A - Manufacture of nonlinear resistance element - 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 nonlinear resistor whose main component is zinc oxide.
In particular, the present invention relates to a method of manufacturing a nonlinear resistor with an improved electrode forming process.

[Technical background of the invention and its problems]

In electrical systems, overvoltage protection devices are used to protect the electrical system by removing overvoltages that are 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 baking a molded material of silicon carbide (SiC) or zinc oxide (ZnO) mixed with a metal oxide. Zn
O-based non-linear resistors have impressive non-linear characteristics in the small current range and have a sharp rise up to the large current range, so overvoltage using SiC-based non-linear resistors is It is possible to create an overvoltage protection device that is better than the protection device. However, ZnO-based non-linear resistors require many manufacturing processes, are difficult to mass-produce industrially, and suffer from a decline in non-linear resistance characteristics and large variations in their characteristics, as well as problems such as electrification life, discharge capacity, etc. There is a problem that other performance deterioration also occurs.

[Purpose of the invention]

The present invention has been made to address the above-mentioned problems by focusing on the electrode formation process, which is closely related to the characteristics among many manufacturing processes, and to address the problems described above, such as the decrease in non-linear resistance characteristics, variations in the characteristics, and It is an object of the present invention to provide a method for manufacturing a nonlinear resistor with improved performance.

[Summary of the invention]

In order to achieve the above object, the present invention has two electrode forming layers in the step of forming an electrode in a method for manufacturing a non-linear resistor.
It is characterized in that it is provided in ~5 layers and the total thickness of the electrode layer is 0.05 to 0.2 mm.

[Embodiments of the invention]

This will be explained below based on embodiments of the present invention. Bismuth oxide (Bi20) is added to zinc oxide (ZnO) powder, which is the main component.
．． ), Wk antimony (Sb203), 'fIl
chromium oxide (chromium oxide r203), cobalt oxide (Coo)
and manganese oxide (MnO) powder, respectively.
It is added in a range of 01 to 6.0 mol% and mixed in a ball mill. At this time, the oxide and an organic binder such as polyvinyl alcohol are mixed simultaneously. The mixture thus obtained is placed in a dry granulation device, for example a spray dryer, to form spherical agglomerates. This powdery mixture is pressed into a disk having a diameter of 80 mm and a thickness of 30 mm, for example. This molded product is placed in an electric furnace and fired. Firing temperature is 1200℃
For example, 6 hours is appropriate for 1 hour. After firing, the disc-shaped fired product shrinks more than before firing, but has a nearly uniform structure and density.

An insulating collar is applied to the side surface of this fired product and baked. Thereafter, the circumferential surface is polished and metallized with aluminum, for example, to provide electrodes and complete the non-linear resistor. FIG. 4 shows a cross-sectional view of a non-linear resistor manufactured according to the present invention. In the figure, 1 is a fired body with an electrode 2 on its circumferential plane.
is formed. However, the parallelism of the non-linear resistor has deteriorated due to polishing or the like. When considering a lightning arrester, the quality of the contact between the electrode surfaces when resistors are stacked has a large effect on the performance, so for example, one layer for forming the electrode on the circumferential plane is applied, pressure is applied, and then another layer is formed. The total thickness of the electrode layer is 0.05 to 0.2o with 2 to 5 layers.
By specifying 0, it is possible to increase the degree of adhesion between the resistors, prevent the occurrence of corona, etc., and make it possible to obtain a stable non-linear resistor. In the above embodiment, aluminum was used for metallization, but it goes without saying that the effects of the present invention can also be obtained with a metallization layer made of a different alloy as long as it functions as an electrode.

The degree of variation in the nonlinear resistor manufactured in this way is
2 and 3. FIG. 1 shows the strength of the surge energy resistance when the electrode formation layer of the non-linear resistor is changed to a thickness of 1 mm and the resistors are stacked in two layers. As is clear from FIG. 1, where the horizontal axis represents the electrode formation layer, the nonlinear resistor according to the present invention has poor adhesion between the resistor and the electrode when the electrode formation layer is one layer. sparks between the two, and cannot handle surge energy. In addition, when six or more electrode formation layers are provided, the electrode separates from the resistor and discharge occurs between the electrode and the resistor, making it impossible to handle surge energy.

FIG. 2 shows variations in surge energy withstand capacity of nonlinear resistors manufactured by the method of the present invention and the conventional method. In other words, the horizontal axis shows the surge energy (J) when a nonlinear resistor is destroyed by flowing a surge current, and the vertical axis shows the applied surge energy when the total quantity is set as 100%. The quantity withstood is taken as a relative value. In FIG. 2, curve A shown as a solid line shows the distribution of non-linear resistors according to the method of the present invention, and curve B shown as a dotted line shows the distribution of non-linear resistors according to the conventional method. As is clear from this figure, it can be confirmed that the variation in the surge energy withstand capacity is smaller in the curve A according to the method of the present invention than in the curve B according to the conventional method.

FIG. 3 shows the strength of the surge energy resistance when the electrode forming layers of the non-linear resistor are fixed to three layers and the thickness is varied. The horizontal axis represents the thickness of the electrode, and the vertical axis represents the processing energy that withstands the applied surge energy.

As is clear from FIG. 3, when the thickness is less than 0.05 am, the adhesion of the electrode is poor, and when it is more than 0.2 m, the electrode peels off and cannot handle surge energy. In FIG. 3, the formation layer is three-layered, but it has been confirmed that the effect of the present invention can be obtained when there are two to five layers.

〔Effect of the invention〕

As described above, according to the present invention, in the step of polishing both sides of a sintered body containing zinc oxide as a main component and forming an electrode, two to five layers of the electrode are formed, and the thickness of the electrode layer is reduced to zero. .05~0.
By specifying the thickness to 2 mm, it is possible to increase the adhesion of the electrodes, and the surge energy withstand characteristics, that is, the discharge withstand characteristics are superior to conventional methods, and it is possible to provide a method for forming electrodes of a nonlinear resistor of higher quality.

[Brief explanation of drawings]

1, 2, and 3 are curve diagrams illustrating the electrical characteristics of a nonlinear resistor manufactured using the manufacturing process of the present invention;
The figure is a cross-sectional view of a non-linear resistor manufactured according to the present invention. Agent Patent Attorney Norihiro Ken Yudo Mitsumata Hirofumi [J] Figure t.

Claims (1)

[Claims] In a method for manufacturing a non-linear resistor, the electrodes are formed by polishing both surfaces of a fired body made by firing a mixture of zinc oxide as a main component and at least one kind of metal oxide,
A non-linear method characterized in that in the step of polishing both planes of the fired body and forming an electrode, two to five electrode formation layers are provided so that the total thickness of the electrode layer is 0.05 to 0.2 mm. Method of manufacturing a resistor.