JPS6265302A - 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 nonlinear resistor 1 whose main component is zinc oxide and whose sintered body itself has Narita nonlinearity.

[Technical background of the invention and its problems]

Nonlinear resistors are generally called varistors, and their excellent nonlinear voltage-current characteristics are widely used in lightning arresters and surge absorbers for the purpose of stabilizing the Four Kings or absorbing surges. A typical example is a zinc oxide varistor.This has zinc oxide as its main component, and small amounts of oxides such as bismuth, antimony, cobalt, manganese, and chromium are added to this to cause voltage nonlinearity. After mixing, granulation, and molding, the sintered body 1 is sintered at a high temperature in the air, and an electrode is attached thereto.

Its nonlinearity is very excellent, and the sintered body consists of zinc oxide particles and the surrounding additives (grain boundary layer formed by two) and a spinel phase mainly composed of zn1Sh!OIl.
The excellent nonlinearity is thought to be due to the interface between the zinc oxide particles and the grain boundary layer. Therefore, it would be ideal if the spinel phase could be eliminated, but this is more difficult than its generation mechanism.

In other words, in order for the zinc oxide varistor to exhibit its excellent nonlinearity, the roi and 8b components are indispensable, and the bismuth and sb components react with ZnO to form Zn between 650 and 950'C.
, Bi, Sb, O,, (pyrochlore phase), 1
At 000'Q or more, the grain boundary layer mainly composed of Bi, 01 and Zn, 8b, O, (spinel phase) are controlled, and the grain boundary layer becomes Zn, 5i04 component and Bi acidic component. There is an example of an amorphous layer composed of Zn.
The spinel phase, which is the main component of 18b*OIt, could not be removed.

[Purpose of the invention]

The present invention has been made in view of the above point 1, and aims to provide a nonlinear resistor that improves nonlinearity, prevents variations in electrical characteristics, and has homogeneous characteristics.

[Summary of the invention]

In order to achieve such an object, the present invention provides a nonlinear resistor containing ZnO as a main component and at least Bj and Sb components as subcomponents. and the amount of Al is 1
~1100pp 1 d.

[Example of the present invention] Hereinafter, the present invention will be explained based on two examples.

First, bismuth oxide (B') is added to zinc oxide (ZnO) powder.
Powders of cobalt oxide (CO), manganese oxide (MnO), antimony oxide (Sbzos), and niragel oxide (Nip) were added in the range of 0.5 to 5 mol. In order to mix, water 1, dispersant, binder, and lubricant were added to a mixing device (Futariresara 1:Humant (NOl)!・9H80) at the desired composition ratio. For example, granulate once so that the average particle size is 100 microns, press this powder (= pressed diameter 55Nm thickness 30mm)
Disc No. 4 (2 molded. Added dispersant, binder,
After baking at 500℃ in air to remove lubricant in advance,
A high-resistance layer forming product prepared in advance was applied to the element body calcined at 20°C. This element body was fired at a temperature of 1050 to 1300°C.

Both sides of the sintered body thus obtained were polished, and two electrodes were installed using thermal spraying to form a non-linear resistor and its characteristics were measured.

The amount of A/in the spinel phase was determined as follows.

The sample from which the electrode was removed was placed in an HCe solution (both ZnO
The particles and the Bi, O, phase are dissolved and the insoluble spinel crystal phase is extracted. The extracted spinel crystal phase was chemically analyzed to determine the amount of Al in the spinel crystal phase.

FIG. 1 is a diagram showing the relationship between All in the spinel phase and nonlinearity of the nonlinear resistor manufactured as described above, and the nonlinearity is vl. KA/” is expressed as 1 mA.

As is clear from Figure 1, A/9 in the spinel phase is 1
~1100pp range, 2 times, 10
IA/'V1! The value of IIA can be reduced, that is, nonlinearity can be improved.

゛Also, the usefulness of the present invention is vII during mass production! This can be seen from the fact that the variation among individuals is distributed as shown in Figure 2. The human curve in Figure 2 has a human curve of 10p in the spinel phase.
This is the variation distribution at pm, and the 8 curve is 5001)p
This is the variation distribution when m.

In Figure 2, for example, if a product that deviates from the control value by 30 inches or more is determined to be one lot defective, the 8 curve will be approximately 3
However, according to the present invention, the standard variation is 42 as shown by curve A, and defective lots can be completely eliminated.

In addition, the characteristics shown in Figure 2 1 = A/J'1 in the spinel phase.
10 and 500 ppm, but when the amount of Al in the spinel phase is in the range of 1 to tooppm, the curve is similar to the curve 8), and when the amount of Al in the spinel phase is in the range of 1 to tooppm, the curve is 11) I) less than m or more than lQQppm, the same trend as the 8 curve is shown. It has been confirmed that the

The nonlinear resistor obtained in this way guarantees excellent reliability when used in power surge arresters, etc. (2), which is important from a practical point of view. .

Second, although an oxide was used as a raw material in the embodiments of the present invention, any material that can be sintered to form an oxide may be used, such as hydroxide, carbonate, oxalate, etc. There is no guarantee that the same effect can be obtained.

〔Effect of the invention〕

As explained above, according to the present invention (=), it is possible to improve nonlinearity, prevent variations in constant air characteristics, and provide a nonlinear resistor having homogeneous characteristics.

[Brief explanation of drawings]

FIG. 1 is a characteristic diagram showing the relationship between the amount of Ae in the spinel phase and nonlinearity of a nonlinear resistor according to an embodiment of the present invention, and FIG. 2 is a characteristic diagram showing the variation in characteristics during mass production. . Agent Patent Attorney Yudo Nori Chika Hirofumi Suhi 2Washi Saime Junior High School/lAi amount (pprn) Figure 1 Figure 2 vA

Claims (1)

[Claims] Zn_7Sb_2O_1_2, a nonlinear resistor containing at least Bi and Sb components in ZnO and exhibiting voltage nonlinearity
1. A non-linear resistor having a spinel phase containing as a main component, wherein the amount of Al in the spinel phase is 1 to 100 ppm.