JPS59106103A - Oxidized zinc 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 nonlinear resistor containing zinc oxide ZnO as a main component.

A nonlinear resistor element whose main component is zinc oxide (hereinafter referred to as ZnO
Because they exhibit excellent nonlinearity, they are used for semiconductor devices such as diodes, transistors, and thyristors, and as surge absorbers for electrical equipment.

In general, this type of ZnO element uses an acid as a main component to produce a ZnO element with good sinterability by liquid phase sintering, as well as bismuth, molybdenum oxide, cobalt oxide, and l-, which promote the above-mentioned functions of bismuth oxide. Nickel oxide.

It is made of at least one material such as titanium oxide (0.1 mole or more each). Figure 1 shows ZnO obtained by firing.
The microstructure of the device is shown in which A is a zinc oxide crystal grain, and a thin insulating crystal layer B containing bismuth oxide as a main component is formed at each zinc oxide grain boundary.

By the way, B i 203 (which has a lower melting point than riZnO) is added to promote crystal growth of ZnO particles by liquid phase sintering.
Conventionally, in order to exhibit this function, the amount of Bi2O3 was adjusted to 0.1rn, oβchi or more of all components (0.1rn in weight ratio).
(67% or more) was used in large amounts, preferably several hundred percent or more. For this reason, the raw material efficiency for manufacturing ZnO elements is decreasing, and bismuth oxide is polymorphic and has a low temperature (4
The electrical properties of the ZnO element change as the crystal system changes even when processed at temperatures between 0 and 650°C, and its thermally stable properties are an advantage. Bismuth oxide is highly volatile and if a worker inhales its vapor, it will have a negative effect on the human body, so it is desirable to use it in small quantities.For this reason, when glass frit is used instead of bismuth oxide However, during firing, the crystal growth of zinc oxide is insufficient and the formation of grain boundary layers is also incomplete, resulting in poor nonlinearity compared to those using bismuth oxide.

The present invention was made in view of this point, and its purpose is to use W2B and A10 as additives.
By using Os as △, we aim to provide this type of ZnO element that exhibits excellent nonlinearity even when the amount of Bi2O3 is extremely small. Examples will be explained in detail.

The ZnO element of the present invention contains zinc oxide with a purity of 99.91, bismuth oxide in an amount of 0.005 to 0.1 mol %, tungsten oxide and molybdenum oxide in an amount of 0.01 to 0, respectively.
5 mail %'+manganese oxide 0.03-3.0
Add mo1% of each optional [''shi], and further add zinc borosilicate glass frit to the total amount of all components at a rate of 0.01 to 1%.
It consists of the following: LOwt section. The ZnO element of the present invention comprising such components can be obtained in the following manner. First, weighed raw materials are sufficiently wet-mixed so as to have a predetermined composition ratio, then granulated, formed into a desired size, and calcined. Thereafter, baking is performed at an arbitrary temperature of 1000°C to 1300°C for 6 hours.

Firing may be carried out by the conventionally used method described above, but by preventing or supplementing the volatilization of bismuth oxide, molybdenum oxide, and tungsten oxide,
In order to obtain a ZnO element with high sinterability, the method shown in FIG. 2 is used.

In FIG. 2 (α), the pedestal 2 is placed inside the firing pod 1,
A granulated powder 3 made of the same ingredients as the element of the present invention described above is spread on the pedestal 2, and a ZnO element molded body 4 is placed thereon and fired.

Fig. 2(b) is the same as Fig. 2(a), but the difference is that Bi2O5z
Powder 5 of WO3 is placed and firing is performed.

In Fig. 2(c), the powder is granulated throughout the inside of the firing pod, and Fig. 3 shows each sample A and B shown in the table.

Voltage when firing C using the conventional firing method described above -
It is a current characteristic diagram.

As is clear from Table 3, it was confirmed that by mixing and adding molybdenum oxide, tungsten oxide, etc., even in a trace amount of bismuth oxide, the sample exhibited better characteristics than sample C without the addition of bismuth oxide. It was also revealed that nonlinearity was further improved by adding manganese oxide.

According to the experimental results, the amount of bismuth oxide added is Q,
Below 0.005 moa, it is insufficient to form an insulating crystal layer at the zinc oxide grain boundaries;
If the amount is more than 100%, it will be too much to form the layer, and the excess will volatilize and dissipate.

Molybdenum oxide and tungsten oxide are Bi2O5 respectively.
The role of promoting the formation of a layered structure is 0.01.
If the mo is less than 1%, no effect will be seen, and 0,5 mai
When l is 1 or more, it exists concentrated at the grain boundaries of ZnO, and the nonlinear index @) decreases. In addition, glass frit is
Although it acts as a solvent, it is not unevenly distributed only in the grain boundary layer, so at temperatures above 1.0%, the excess diffuses into the zinc oxide crystals, so Zn
The nonlinearity of the O element was reduced, and there was no difference between 0 and 01wt or lower. Note that this glass flint acts as a solvent during firing, so in order to ensure sufficient growth of zinc oxide and the crystals of the insulating crystal layer, ZnO3-65
wt person in charge.

BzOslO~35wt%, 5i0210~75wt%
A zinc borosilicate glass frit consisting of is used.

Furthermore, with manganese oxide, the nonlinearity in a large current range deteriorates when the coefficient exceeds 0.03 moA.

As described above, the present invention provides Bi as an additive for zinc oxide.
The amount of 2O3 is 0.005 to 0.1 mo 42%,
In order to prevent the layered structure of the grain boundary layer from deteriorating by the minute amount, WO2 and MoO3 are each added in the range of 0.01 to 0.
3moβ is added to promote the formation of a layered structure by Bi2O3. Therefore, according to the present invention, the amount of added bismuth oxide etc. is 1/10 compared to the conventional one.
As described below, raw material efficiency is improved, and since the amount of bismuth oxide added is small, there is less volatile content and less harmful effects on the human body. Furthermore, by combining the high activity of molybdenum oxide with the thermal stability of tungsten oxide, the reaction initiation temperature and reaction rate of bismuth oxide can be set in an appropriate range, and volatilization can be prevented, resulting in excellent nonlinearity. A ZnO element can be obtained.

Furthermore, by adding Mn0z, the nonlinear index of the ZnO element becomes large and constant over a wide range, so it is particularly effective as a surge absorber when many repeated surges occur over a long period of time.

Furthermore, as is clear from FIG. 3, the ZnO element according to the present invention has a lower withstand voltage per 1 V element than those used in conventional arresters, so the energy consumption per unit volume is kept low and the withstand voltage is lower. This improves the characteristics and makes it easier to adjust the device's limiting voltage (voltage when a current of 1 mA flows). Of course, the same effect can be obtained even if

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the fine structure of a ZnO element, FIG. 2 is an explanatory diagram showing a method of firing a ZnO element molded body of the present invention, and FIG. 3 is a current-voltage characteristic diagram of the ZnO element of the present invention. patent applicant

Claims (2)

[Claims] (1) In the case where zinc oxide is the main component and 3° of bismuth etc. is added to this zinc oxide in the form of an oxide or salt as an additive, bismuth is added as the additive in the form of Bi20B. In terms of 0.005 to 0.1 mole, tungsten and molybdenum are
0.01 to 0.5 mohe borosilicate glass frit to the total amount of all components in terms of oO3 form.
1. 1. A zinc oxide nonlinear resistor, characterized in that it is formed by adding Owt and firing at a temperature of 1000 to 1300°C. (2) In the case where zinc oxide is the main component and bismuth, etc. is added to this zinc oxide in the form of an oxide or salt as an additive, the bismuth as the additive is converted into the form of Bi2O3. Then, 0.005 husband WOs,
0.01 to 0.5 mole each in terms of Mo5s form, and 0.03 to 3.0 mole in terms of manganese in MnO3 form.
The amount of borosilicate glass frit is 0.01 to 1.0 molar relative to the total amount of all components. Owt% added 1000~
A zinc oxide nonlinear resistor characterized by being fired at a temperature of 1300°C.