JPS59208702A - 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] [Technical Field of the Invention] This invention relates to a method of manufacturing a non-linear resistor mainly made of ZnO used in lightning arresters and the like.

[Technical background of the invention and its problems] Mainly composed of ZnO, Bi, Sb, Co, Mn, Cr,
After adding a small amount of oxide such as Si, mixing, granulating, and molding, this molded body is fired at a temperature of 1,100 to 1,300°C, and electrodes are attached to this sintered body to form a non-linear material mainly made of ZnO. A resistor is obtained. However, this is not used in applications such as lightning arresters, and it is necessary to form a high-resistance layer on the side surface of the sintered body. This is to prevent creeping flash when a large impact current is applied, and to reduce deterioration due to humidity.

As an example, 5in2-8b203-Bi20. There is a method in which a material consisting of the above is applied to the molded body and then fired to form a high-resistance layer on the side surface of the sintered body. (4￥ Kosho 5
3-21516) However, in this method, the sintered body and the high-resistance layer often separate from each other because the shrinkage rates of the molded body and the high-resistance layer during the integral firing process are different. As a method to solve this problem, a method has been proposed in which the compact is pre-fired in advance, then a substance that forms a high-resistance layer is coated, and then main-fired to form a high-resistance layer on the sintered body. . (% Kosho 54-1
0720), in this method, the high-resistance layer is completely adhered to the sintered body, and the original purpose can be completely achieved.

However, this strength requires two firing steps, which is not economical, and also reduces the cost of nonlinear resistors (decreasing the nonlinear index due to the instability of the yellowing crystal phase). It had the disadvantage of poor tonne life characteristics.

OBJECT OF THE INVENTION The present invention was made to eliminate the above-mentioned drawbacks of the conventional technology. The purpose is to provide a method for manufacturing the body.

[Overview of the invention] In order to achieve the above object, the present invention molds a ZnO mixture with ZnO as a main component, and the 0111 and 1(+
203-81) 203-8in2-basic magnesium carbonate (Mg4(01()2 (C03)3.31-),
, O), wherein the composition of the high resistance layer forming material is Bi2O, 20-30 wt%, SbS.
10 to 30 wt% of basic magnesium carbonate (M
g4(OH)2(CO3)3.3H70).

Examples of the invention] The present invention will be explained in detail below using examples.

Bi, 03. Co2O3, MnO2+ ”20S+
Sin, each hQ, 5mo/%.

5b20. , NiO at each h 1 mat%, A/,
0.25xtOwt%, and the rest was ZnO. These raw materials were accurately weighed. In order to thoroughly mix these powder raw materials, they were placed in a dispersion/mixing device together with water, a dispersant, a binder, and a lubricant to be dispersed and 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 80 mm and a thickness of 30 m.

In order to remove the added dispersant, binder, and lubricant in advance, it was fired in air at 500°C to obtain a molded body.

On the other hand, BhOs 27wt%, Sb20342wt%
, Sin231% were weighed, and 0.5. to, 20, 30.50W pass basic magnesium carbonate (Mgt(OH)2(CO3)3・3i
-4o) was added and mixed in a ball mill for 24 hours with a binder consisting of water and polyvinyl alcohol to form a slurry and prepare a high-resistance layer forming material.

Thereafter, the high resistance layer forming material +F slurry is sprayed onto the side surface of the molded body using a spray gun.

After applying the sieve resistance material, it was placed in a sintering machine and fired at 1150'G in the air, and both sides of the obtained sintered body + Mr.
It was polished, reheated at 500"C, and aluminum metallic poles were attached to both planes. FIG. 1 is a side sectional view of the completed non-linear resistor.

After that, the electrical characteristics of the completed nonlinear resistor were measured, and the energization life ρ was tested. Table 1 shows the results.

1.For comparison, as a conventional example, Ajj molded product 05
Pre-baked at 0°G to form a high resistance layer on the sides,
The calcined body is a dog.

Prepare a high resistance layer forming material slurry that does not contain basic magnesium carbonate among the pre-ml high resistance layer forming materials, and spray it on the side of the calcined J compensatory using a spray gun.
A nonlinear resistor was obtained by JJ.

Table 1 As is clear from the results, when the amount of basic magnesium carbonate added is 0.5+50wt%, the high resistance layer peels off, and the superiority or inferiority in the humidity deterioration and shock large current tests is clear. Further, the addition amount of basic magnesium carbonate of this example to +20+30 wt % is superior in non-linear characteristics as compared to the conventional example.

As mentioned above, the conventionally known high resistance layer forming material (Bi
, 0s-8b203-8in, ) to 10-30wt%
It has become clear that by adding basic magnesium carbonate, the molded body and the high-resistance layer can be fired in one time without pre-firing the molded body, and results equivalent to or better than conventional methods can be obtained. In order to investigate the cause of this, we investigated the shrinkage process during the firing process of the high-resistance Iζ-forming phase O. The difference was within the 1Q section.

However, one thing to know is that the feeder and high-resistance layer will not separate.

Furthermore, as a result of X-ray diffraction, the high-resistance layer formed on the sintered body has Z
n25104 + Zn7sb2o, 2. (Zn M
g) 75b2012, etc., which completely reacted with the sintered body and turned into a high-resistance material.

As previously known, high-resistance layer forming materials are used.
20! +20-. 3 Qw t%+ 5b2034
0-50wt%, 8i0□30-40wt candy, basic magnesium carbonate 0.5゜IO, 2Q
Exactly the same results were obtained when the same procedure as in the above example was carried out by adding 50 wt% of , do .

[Effects of the Invention] As described above, according to the present invention, the molded body and the high-resistance layer forming material can be integrally fired without pre-firing the molded body, and the high-resistance layer forming material can be fired in one piece, which improves the stability when a large impact current is applied. It can prevent creeping flash and reduce humidity deterioration, as well as improve nonlinearity compared to conventional examples, and its industrial value is extremely large.

[Brief explanation of the drawing]

The drawing is a sectional view of a non-linear resistor according to an embodiment of the present invention. ■ -Sintered body 2--Electrode 3--High resistance layer

Claims (1)

[Claims] 1. A mixture containing ZnO as the main component is molded, and Bi2O3-8b203-8i02-basic magnesium carbonate (Mg4(OH)2(COa)g
・After applying the high resistance layer forming material consisting of 3H20),
In the method for manufacturing a non-linear resistor by firing, the composition of the high-resistance layer forming material is +3120320-30wt%;
8b, 0.4Q-5Qwt%, 5in230-40w
basic magnesium carbonate (Mg4(OH)2(Cos)s-38,O) in an amount of 10 to 50 wt% of the weight of the composition.
A method for manufacturing a non-linear resistor, characterized in that: