JPS61102004A - Manufacturing method of voltage 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 Field of the Invention The present invention relates to a method for manufacturing a voltage nonlinear resistance element containing zinc oxide as a main component.

Conventional configuration and its problems SiC is used as a ceramic material with voltage non-linear resistance characteristics.
There are baristas and baristas whose main ingredient is zinc oxide. The current σ)-voltage (!/) characteristic of such a varistor is approximately expressed as I-(V-)Ct. Here, C is a constant specific to the varistor, and α is a voltage nonlinear index.SiC varistors utilize contact barriers between SiC particles,
α is about 2 to 7. Recently, the mainstream type of varistor is a varistor whose main ingredient is zinc oxide.
Ru. This zinc oxide varistor is made of zinc oxide (ZnO) K B
This is an element obtained by adding a small amount of a metal oxide such as i2O3, Coo, MnO2°5b205, etc. and firing it, and its voltage nonlinearity index α is as high as 6o. This zinc oxide varistor has excellent performance in absorbing high voltages, so it is used for the purpose of stabilizing electronic equipment and temporarily protecting it from abnormal high voltages (surges).

Normally, when making a voltage nonlinear resistance element mainly composed of zinc oxide, trivalent atoms are added to improve the voltage suppression effect when an abnormally high voltage is applied to the element. This is 3
This is because the specific resistance of zinc oxide is lowered by the valence control effect due to the solid solution of valence atoms in the zinc oxide particles. However, the optimum amount of trivalent atoms to be added is an extremely small amount of 1°. . . If it is less than mol %, the voltage suppressing effect will be small, and if it exceeds -100 mol %, the voltage nonlinearity index α will deteriorate, and leakage current will increase under normal usage conditions, making it impractical. Therefore, careful attention must be paid to the addition of trivalent atoms and they must be uniformly dispersed in the raw material. Usually, an A1 atom is used as a trivalent atom, and a trace amount of 12o3 is added.

In the normal manufacturing process, first a specified amount of Bi, 2o3
゜CO□03r Additives such as MnO□ and Al203 are wet-mixed in a pot, and then the mixed additives are wet-mixed with the main raw material ZnO in a Lab Isper mill or Thoron mill, and the mixture is dried using a spray dryer. drying,
Perform granulation to create granulated powder. A voltage nonlinear resistance element is obtained by molding this granulated powder and firing it to form an electrode. However, since the amount of Al205 is extremely small compared to other raw materials, and since the mixing is done by mechanical force using a pot or the like, the state of dispersion of the material 1 is not sufficient.

A partial concentration distribution of Al occurs, causing instability in the electrical characteristics of the voltage nonlinear resistance element.

OBJECTS OF THE INVENTION In view of the above-mentioned drawbacks, an object of the present invention is to provide a manufacturing method for manufacturing a voltage nonlinear resistance element having an excellent voltage suppressing effect without variations in characteristics.

Structure of the Invention In order to achieve this object, the method for manufacturing a voltage non-linear resistance element of the present invention is to provide a method for manufacturing a voltage non-linear resistance element of the present invention. By adhering liquid fine particles having a uniformity of 0.05 to 100%, it is possible to make the distribution of Al atoms in the powder uniform and to obtain a voltage nonlinear resistance element with stable characteristics. Usually, granulated powder mainly composed of zinc oxide granulated with a spray dryer has an average particle size of 100 to 150 μm, while the average particle size of liquid particles generated by an ultrasonic atomizer is 5 to 150 μm.
It is 10 μm thick and adheres evenly to the granulated powder, and A in the granulated powder.
l It does not create shading of density.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

The figure is a schematic diagram showing an embodiment of an apparatus for carrying out the method of manufacturing a voltage nonlinear resistance element of the present invention. 1 is a spray dryer, 2 is a granulated powder, 3 is a hollow container, 4 is an ultrasonic atomizer, 5 is a liquid containing A1 atoms, 6 is a humidifying section,
7 is a granulated powder that has been humidified and has one human atom attached thereto, and 8 is a storage container for the granulated powder.

First, add Bi2O3, Coo to ZnO powder 2ooKp.
.

MnO2,5b205. 0.1 to 1 NiO each
% by mole, pure water and organic binder were added and mixed using a disper mill. Next, the slurry-like mixture thus obtained was dried and granulated using a spray dryer 1. Next, aluminum nitrate (Al(NO5)
A liquid 5 containing Al atoms was prepared by dissolving 3.9H2o) in water, and an ultrasonic atomizer 4 was used to produce liquid fine particles. The aqueous solution was a 5% solution of Human 1 (No. 5) 5.9H20. Next, as shown in the figure, granulated powder 2 is poured into a hollow container 3 from a spray dryer 1. On the other hand, the outlet of the ultrasonic atomizer 4 for liquid particles containing one atom is inserted into the through hole in the wall of the hollow container 3, and the atomized liquid particles are injected into the hollow container 3 and granulated. A on the surface of powder 2
A humidifying section 6 is created to which liquid fine particles containing one atom are attached.

Then, the granulated powder 7 having A1 atoms attached to its surface was placed in a storage container 8. Here, the amount of aqueous solution used is 2oo of granulated powder.
The atomization amount was 5000 cc with respect to Ky. Next, these granulated powders were molded into a size of 25φ x 2t using a hydraulic molding machine at a pressure of 400Kp/crl, and fired in air at 1200°C for 6 hours. The shape of this sintered body is 20φ
×1.6t (M). A silver electrode was applied to the side surface of this sintered body, baked at 800'C, and the electrical properties were measured. As a result, the varistor voltage v + m A ”' 20o
V, the limiting voltage characteristic that represents the voltage suppression effect is v4001
/vjmA""45, and the standard deviation was 0.015.

On the other hand, the characteristics of the device made using the conventional method are v, = 2ooy.

v4oo, /v, In, = 1.50, standard deviation is 0
．． 076, it can be seen that the manufacturing method of the present invention is superior.

Effects of the Invention As described in detail above, the present invention has the advantage of adding Al generated from an ultrasonic atomization device to granulated powder containing zinc oxide as a main component.
By attaching liquid fine particles containing atoms, it is possible to provide a voltage nonlinear resistance element that has an excellent voltage suppression effect and less variation in characteristics, and has great practical value.

[Brief explanation of the drawing]

The figure is a schematic diagram showing an embodiment of an apparatus for carrying out the method of manufacturing a voltage nonlinear resistance element of the present invention. 1... Spray dryer, 2... Granulated powder, 3... Hollow container, 4... Ultrasonic atomizer, 5...・Liquid containing Al atoms, 6
... Humidification section, 7 ... Granulated powder that has been humidified and has Al atoms attached, 8 ... Storage container for granulated powder.

Claims (1)

[Claims] A method for manufacturing a voltage nonlinear resistance element, which comprises attaching liquid fine particles containing Al atoms generated from an ultrasonic atomizer to a granulated powder containing zinc oxide as a main component.