JPS5879702A - Method of producing 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 The present invention relates to a non-linear resistor, and more particularly to a method for manufacturing a non-linear resistor used in an overvoltage maintenance device in an electrical system.

In electrical systems, overvoltage maintenance devices are used to remove overvoltages superimposed on normal voltages and maintain electrical systems.

This overvoltage wire maintenance device uses a nonlinear resistor that exhibits almost insulating properties at normal voltage and has a relatively low resistance value when overvoltage is applied.

Non-linear resistors are made of boron carbide (SIC) or zinc oxide (
It is made by mixing metal oxide with zno) and firing the molded material.

For example, Zn0 flomole-1 magnesium oxide (MgO
) 16 mol, bismuth oxide (Biton), antimony oxide (sb, O,), cobalt oxide (Coo)
, manganese oxide (MnO), chromium oxide (Or!), and iron oxide (F@!), each weighing 0.05 to 3.5 moles per 8 mole and mixed.

The mixture is pressed and formed into 1200t:' to 13
Baked at a temperature of 00C for 8 hours, the diameter is 60cm and the thickness is 1Q.
A disc-shaped non-linear resistor material of m is made, and electrodes are formed by metal spraying to form a non-linear resistor.

In a non-linear resistor that moves at true speed in this way, the rate of change of the non-linear resistor when a large current pulse is applied is large, and therefore it is difficult to apply an overvoltage protection device that receives pulses or voltage surge pulses over a long period of time. is unsuitable, and a nonlinear resistor with stable electrical characteristics over a long period of time is desired.

The present invention was developed in view of the above-mentioned needs, and it is an object of the present invention to provide a method for manufacturing a nonlinear resistor whose electrical characteristics are less likely to deteriorate even when overcurrent pulses are repeatedly applied over a long period of time.

Next, the present invention will be explained in detail. For example, 80 mol of ZnO and at least one metal oxide, such as Mg01.
4 moles - 1 BitOa2 moles 18111.0.1.5
Mole %, Co01.1 mole-1Or, 0.0.5 mole-1Mn00.55G, F-false 0.4 mole.

The weighed oxide is then placed in a whole mill and mixed with deionized water by running the whole mill for 24 hours.

For example, polyvinyl alcohol is mixed with the oxide before mixing at a weight ratio of 1/100 to the oxide.

The nota oxide and polyvinyl alcohol are mixed substantially homogeneously.

This is then mixed into nine slurry-like oxides in a spray-drying granulation device, for example! For example, put it in a spray dryer and dry it with a particle size of 10
Form into spherical agglomerates of 0 to 300 Icron.

This powder-like mixture is pressed, for example, with a diameter of 10 cm.
, and molded into a disk shape with a thickness of 25111 mm.

This molded product is placed in an electric furnace and fired. The firing temperature is, for example, 1300C, and the appropriate time is 6 hours.

After firing, the disc-shaped fired product shrinks more than before firing, but has a substantially homogeneous composition and density.

On the side surface of this disc-shaped fired product, polyvinyl alcohol is dissolved in water and a hydrotactic binder is used to prepare powdered glass such as lead glass, quartz glass, or borosilicate glass and aggregate such as feldspar, zirconia, etc. Make a paste of zircon, alumina, and spinel and apply spray S. The particle size of the glass powder is preferably 7° to 200°.

The coated fired product is heated to a temperature of, for example, 300m to 10m.
The coated material is baked into the fired product by placing it in a 0OC furnace.

Next, both sides of the disc-shaped fired product are lightly polished to expose the fired product. For example, aluminum is metal sprayed on this exposed surface to form electrodes and the nonlinear resistor is completed.

The electrical characteristics of the nonlinear resistor manufactured in this manner are shown in FIGS. 1 and 2.

FIG. 1 shows the rate of change (Δv/v1mA) in the value of vl when up to 10KAI2) current Iioo times are applied. In the figure, curve A shows the value of the non-linear resistor produced by the conventional manufacturing method, and curve B shows the value of the non-linear resistor of the present invention. As is clear from the figure, the electrical characteristics of the nonlinear resistor produced by the manufacturing method of the present invention were significantly improved.

FIG. 2 shows the pass rate when the applied rectangular wave current value was varied up to 100 Km'. The curve M is the pass rate of the conventional nonlinear resistor, and the curve #sB is the pass rate of the nonlinear resistor produced by the manufacturing method of the present invention.

As is clear from the figure, when the applied laminar flow is small, the difference between both curves M and B is small, but when a large current pulse is applied, the acceptance rate of the conventional nonlinear resistor drops significantly.

In the above examples, the content rate of zinc oxide and the composition and content rate of metal oxides are not limited to the above examples.

Furthermore, it goes without saying that the conditions of the process are not limited to those of the above embodiments.

As explained above, according to the present invention, a mixture of powdered glass and aggregate to be applied to the side surface of a non-linear resistor is made into a paste using a water-soluble binder made by dissolving polyvinyl alcohol in water. As a result, it is possible to manufacture a nonlinear resistance element whose electrical characteristics change little even when repeated overcurrent pulses are applied over a long period of time.

[Brief explanation of drawings]

FIGS. 1 and 2 are diagrams illustrating the electrical characteristics of a nonlinear resistor manufactured using the manufacturing process of the present invention.

Claims (1)

[Claims] 1. A step of mixing zinc oxide and powder of at least one metal oxide, and a step of molding the mixture obtained by this mixing step into a disc shape to obtain a molded product. , a step of firing this molded product, and a step of spraying a slurry of a mixture mainly composed of glass powder and aggregate mixed using a water f# binder on the side surface of this disc-shaped fired product, A method for manufacturing a non-linear resistor, comprising the steps of: baking and fixing the coating onto the fired product; and forming electrodes on the fired product. 2. The manufacturing method according to claim 1, wherein the glass powder is any one of lead glass, quartz glass, and borosilicate glass. 3 Claims 1 and 2 in which the aggregate is any one of feldspar, zirconia, zircon, alumina, and spinel.
Manufacturing method described in section.