JPS60170205A - Voltage 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 The present invention relates to a voltage nonlinear resistor containing zinc oxide as a main component.

Prior art Voltage nonlinear resistors (hereinafter referred to as "ZnO elements") mainly composed of zinc oxide (ZnO) have excellent nonlinearity, so they can be used in semiconductors such as transistors and thyristors. The element 7t is used in surge absorbers of electrical equipment and the like. This ZnO element is usually obtained by mixing Zn0K bismuth oxide (Bi,0.)i as a main component with several additives as subcomponents, and molding and sintering the mixture. Here, Bi, 0. is ZnO
Due to its low melting point compared to
It is added to fully promote crystal growth of nO particles. Conventionally, B110m' was used in a large amount of 0.3 mole or more based on the total components in order to fully exhibit its functions.

On the other hand, when manufacturing a ZnO element, a heat treatment step of 400 to 900° C. is required after sintering in order to improve the lifespan of the ZnO element and to form an insulating coating on the outer periphery of the ZnO element. However, due to such heat treatment, the crystal structures of Bt and ol were changed, and the electrical characteristics of the ZnO element were greatly deteriorated. The degree of the decrease is greater as the heat treatment temperature is higher. Such a conventional ZnO element is limited to a certain current range (for example, 100μ
In A to IA), α (nonlinear index) is 20 or more, which is satisfactory, but there is a drawback that α is extremely reduced outside the above range.

In addition, as mentioned above, large amounts of Bi and O are used as additives, but the Clark number of the bismuth (B1) element is 2.
×10−, Bi, 0. are extremely scarce in terms of resources.

OBJECTS OF THE INVENTION The present invention has been made in view of the problems of the prior art, and provides a voltage nonlinear resistor that can be manufactured without using resource-poor B 1 #Osk, has excellent electrical characteristics, and has a long lifespan. The purpose is to provide the body and money.

SUMMARY OF THE INVENTION In order to achieve the above object, the first invention provides 0.1 to 5 mol of manganese oxide (MnO) and antimony oxide (MnO).
Sb, 0. )0.1-5molti, chromium oxide (Or
, O, ) min, Cr, 0. , ZnO, cobalt oxide (Co, 0.), and IVlnO*, and lead oxide (pbo) and sb.0.
The second component obtained by calcining the Tobera mixture is 0.2~
A ZnO element was obtained by adding 20% by weight and completely sintering it.

In a second invention, the first portion and zinc borosilicate glass;
The second component and each component composition is borosilicate zinc glass 0.0
A ZnO element is obtained by mixing 1 to 5% by weight of the second component, 0.2 to 20% of the second component, and the remainder being the first component, and sintering it to form a ZnO element.

EXAMPLES Below, each example of the first and second aspects of the present invention will be described in detail.

1) An embodiment of the first invention First, PbO, Cry O, Sbt Oa mino powder t
A predetermined amount was weighed out at a molar ratio of 4:1:1, and the weighed powders were thoroughly mixed in a centrifugal ball mill to obtain a mixed powder. Then, in this mixed powder all-aluminium crucible,
The calcined product was calcined for 4 hours at a calcination temperature of 1000° C., and the calcined body was pulverized in a centrifugal ball mill to obtain a reaction product as the second component.

On the other hand, as the first component, Z n 098 , 49'7
%le%, Mn0, 0.5 mol%, Sb, 010.5
MoA/%, Cr, 0゜0.5molti, At, 0.3/
A predetermined amount of 1000 molti was weighed. Then, 2% by weight of the above reaction product was added to this first component, and then thoroughly mixed in a rotary ball mill and formed into a disk shape.

Next, this molded body was fired in air at a firing temperature of 1100°C for 6 hours, and both end faces of the obtained sintered body were completely polished, and silver (Ag) electrodes were applied to both end faces, and the temperature was 590°C. A heat treatment was performed for 1 hour to obtain a voltage nonlinear resistor (ZnO element).

Coco[, PbO, Crl (Js, Sb*Os) mixed powder'? When X-ray diffraction was performed on the reaction product obtained by calcining, the X-ray diffraction pattern was as shown in Figure 1. The results of all attribution of the signals in Figure 1 are as follows:
It was found that pyrochlore crystal py was produced as a main component in the reaction product.

FIG. 2 is a graph showing all the voltage-current characteristics of the ZnO element of this example, with the horizontal axis representing the current and the vertical axis representing the voltage. In FIG. 2, solid line 1 shows the characteristics of the ZnO device of this example, and solid line 2 shows the characteristics of the conventional ZnO device containing B i20s k additive as the main component.
In the microcurrent region, the slope of solid line 1 is smaller than the slope of solid line 2. Here, the smaller the slope of the solid line in FIG.
It can be seen that the element has better nonlinear characteristics than the conventional ZnO element. In particular, At, 0. 'e Due to the increased gold content, α in the large current region becomes thicker.

Moreover, FIG. 3 is a graph showing the relationship between each heat treatment temperature and the rate of change in V, 1 mA/yim, and α before and after heat treatment when the temperature of heat treatment, which is the final stage in the ZnO element manufacturing process, is varied. The horizontal axis shows the heat treatment temperature, and the vertical axis shows each rate of change. In addition, the heat treatment time
The duration was 1 hour at each temperature. Here, 'V11mA7m
m is the voltage across 9 when a 1 mA current is applied to a ZnO element with a thickness of 1 mm, and α is the voltage across the ZnO element.
If a voltage of VC'l is generated when a current of 1 is applied, then I=U'' is an index expressed by K. K is a nonlinear resistance.

Also, although it varies depending on this α-ket flow value, it is generally 0.1
mA~l? Values when a current in the FIA range is applied are often used, and the values in this range will be adopted below.

In FIG. 3, solid lines 3 and 4 indicate α, V, and 1 mA/mm % notes of the Z IN O element of this example, respectively, and solid lines 5 and 6 indicate B il On k, respectively.
α and V1 of conventional ZnO element with additive as main component
It shows the characteristics of mA/mm, and in conventional ZnO elements, when the heat treatment temperature for both α, V, and 1 mA/mm is higher than about 500°C, the characteristics rapidly decrease as the temperature rises. . On the other hand, the ZnO of this example
It can be seen that in the element, the percentage properties of both α and Vltn)y'mm hardly change due to heat treatment.

Furthermore, FIG. 4 shows that V
, 1 mA/mm This is a graph showing the rate of increase in leakage current when a full DC voltage of 85% is applied, with the horizontal axis representing the current application time and the vertical axis representing the rate of increase in leakage current.

In FIG. 4, the solid line 7 indicates the characteristic F of the ZnO element of this example. t O+k
Indicates the percentage of conventional ZnO elements with additives as the main component,
The solid line 9 shows the characteristics of the ZnO element especially when the total content ratio of At, O, is 207/1000 molti in this example, and the ZnO elements of this example and other examples shown by the solid line 9 have the following characteristics: It can be seen that the rate of increase in leakage current is lower than that of conventional products, and the h-compound properties are good.

Figure 5 is a graph showing how V2, 5 KA/V, 1 mA, and α change when the content ratio of At, O, is completely changed. Content percentage.

V2, 5KA/V1mA, and α are plotted on the vertical axis. Here, V 2 , 5 KA/V, 1 mA is a ratio of 7 when a current of 1 mA is passed through the ZnO element and a current of 2.5 KA is passed through the ZnO element. In Figure 5, solid line 10T
ri V2, 5 KA/V, l mk percentage,
The solid line 11 shows the characteristics of α, AA, 0. For components other than MnO,,sb,o,.

Cr, 0. were fixed at 0.5% by weight, and the ZnO content was increased or decreased in accordance with A and O8, and the content of the reaction product was fixed at 2% by weight.

As shown in FIG. 5, in order to obtain good % music for both V2, 5 KA/V1 mk and α0.2, 1. p, t, o,
It is necessary that it be contained in the first component in the range of /1000 to 2'/1000 molti.

In addition, in the same way that the effective content ratio of At, O, was confirmed as described above, other additive components, such as MnO,
, Sb, 0. , Cr, 0. , reaction product d) It was tested that in order to obtain good properties, MnO
.

is 0, 1 to 5 mol%, Sb, 0. is 0, 1
~5 mo/l/%, Cr, Q.

is 0.1 to 5 mol.9 The reaction product is 0.1 to 5 mol. relative to the first component.
It was necessary that each content be in the range of 2 to 20% by weight.

11) An example of the second invention First, a reaction product as the second component was obtained in the same manner as in the example of the first invention. On the other hand, as the first component, one having the same component composition as in the example of the first invention was weighed.

Thereafter, they were thoroughly mixed in a rotating ball mill so that the first component was 97.8% by weight, the reaction product was 2% by weight, and the zinc borosilicate glass was 0.2% by weight and 1ft%, and the mixture was formed into a disk shape. . Next, in the same manner as in the embodiment of the first invention, this molded body was fired, an Ag alloy was applied to both end faces, and heat treatment was performed to obtain a ZnO element.

FIG. 6 is a graph showing the voltage-current characteristics of the ZnO element of this example, with the horizontal axis plotting the voltage and the vertical axis plotting the voltage. In FIG. 6, the solid line 12 shows the characteristics of the ZnO element of this example, and the solid line 2 shows the characteristics of the conventional ZnO element whose main components are Bi, O, and all additives. In the large flow region, the slope of solid line 12 is smaller than the slope of solid line 2, and Z
It can be seen that the nO element has better nonlinear characteristics than the conventional product. In particular, since AmO8 is included, α in the large current region becomes large.

In addition, FIG. 7 shows that V,
1. This is a graph showing the rate of increase in leakage 11t current when a DC voltage of 85% of mA/mm is applied, and the horizontal axis shows the leakage time,
The vertical axis represents the rate of increase in leakage current.

In FIG. 7, the characteristics of the ZnO element of this example are shown, the solid line 8 represents the characteristics of the conventional product whose main components are Bi, O, and all additives, and the solid line 14 represents the characteristics of the ZnO element of this example. At, 0. This shows the characteristics of the ZnO element when the content ratio of , it can be seen that the life characteristics are good.

Furthermore, Figure 8 is a graph showing how α changes when each content ratio of AmO3 or zinc borosilicate glass is changed, with the horizontal axis representing the content ratio of each component and the vertical axis representing the content ratio of each component. α
This is the one taken. In FIG. 8, the solid line 15HAm0. By changing the content ratio of MnO, Sb, 0. , the ratio of ZnO was fixed at 0.5 molti and the content ratio of ZnO was set to A.
The total content of reaction products increases or decreases depending on the amount of O1.
α is shown when fixed to a weight handle.

In addition, the solid line 16 shows that the content ratio of zinc borosilicate glass is completely changed, and the content of the reaction product is fixed at 1i% of the alloy on the containing side, and each component in @11 is changed to the entire first component as in the example. The percentage of α is shown when the content ratio of α is increased or decreased depending on the zinc borosilicate glass.

At, 0. As mentioned above, α in the large current region is greatly reduced to 0.
．． In order to play the role of
If it exceeds 71000 mol%, α will actually become smaller by 0.2, so it should be between /1000 and 29/1000.
It is necessary that the content be within the molar range.

Further, in order to obtain good properties, the zinc borosilicate glass needs to be contained in a range of 0.01 to 5% by weight based on the total weight.

In addition, as mentioned above, in the same way as confirming the effective content ratio of Am08 etc., other additive components, namely MnO*
, Sbt O,, Cr, Os, reaction products were tested and found that in order to obtain good properties, MnO
, is 0, 1 to 5 mol/l/%, and SbtOs is 0.1 to 5 mol.

Cr, 0. It was necessary that the total content of the reaction product was in the range of 0.1 to 5 moles by weight, respectively.

By the way, regarding the ZnO element in the example of the second invention, the V before and after the heat treatment when the temperature of the heat treatment, which is the final step in the ZnO element manufacturing process, is varied variously,
When examining the changes in α and 1 mA/mm, the characteristics hardly changed due to the heat treatment, similar to the ZnO element in the example of the first invention.

Note that the first and second present inventions are based on each of the above embodiments = 4.
:1:1, but the present invention is not limited to this example. In other words, it is sufficient that the blending ratio is such that pyrochlore crystals are generated after calcination.

-ti, the components are PbO, Sb, , 0. , C
r, 0. It is not limited to the combination of Or, O,,
ZnO, Go, 0. Pyrochlore crystals can be produced using any combination of PbO and sb, o, and any one or more of MnO and PbO, and the same effect can be obtained.

Furthermore, the calcination temperature and time in the calcination step to obtain the reaction product are 800 to 1100°C, respectively.
and preferably within a range of 1 to 10 hours. If the calcination temperature is less than 800℃, the reaction will be slow;
If it exceeds 100%, a large amount of PbO will volatilize,
Further, if the calcination time is less than 1 hour, the reaction will be insufficient, and if it exceeds 10 hours, the degree of volatilization of PbO will increase.

On the other hand, the firing temperature and firing time in the firing step after mixing the first component and the second component (reaction product) are preferably in the range of 1000 to 1300°C and 1 to 20 hours, respectively. If the firing temperature is less than 1000°C, a dense sintered body cannot be obtained, and the firing temperature is less than 1300'C' (il
- If the firing time exceeds 20 hours, PbO will volatilize and the nonlinear characteristics will deteriorate, and if the firing time is less than 1 hour, a uniform sintered body will not be obtained, and if it exceeds 20 hours, the PbO near the surface will volatilize. This is because the nonlinear characteristics deteriorate.

Moreover, it is preferable that the heat treatment temperature of the sintered body is in the range of 500 to 850°C. This is because if the heat treatment temperature is less than 500°C, the life characteristics and properties of the ZnO element obtained will be poor, and if it exceeds 850°C, the nonlinear characteristics will deteriorate.

In addition, in each of the above examples, in manufacturing the ZnO element,
Although we used all of the centrifugal ball mills and alumina crucibles, these instruments may be of any type as long as they meet the purpose, and are not limited to the π instruments used in each of the above-mentioned examples.

Effects of the Invention As described above, according to the first and second aspects of the present invention, BLOs'e, which has conventionally been used in large amounts as an additive, is not used at all, so that the non-direct M characteristics do not deteriorate due to heat treatment. The non-+MF& index in the minute current region and the large t1M region is larger than that of the conventional one, and the non-linear index is particularly large in the minute current region, so the leakage current during energization is small. In addition, since the increase in leakage current due to long-term energization is small,
A long-life surge absorbing element can be obtained. Furthermore, PbO, etc., with a Clark number of 1.5 x 1.0- is used instead of Bi, 0., which has a Clarke number of 2 x 10-'' and is scarce in terms of resources, so it is advantageous in terms of resources. It has the effect of

[Brief explanation of the drawing]

Fig. 1 is an X-ray diffraction diagram of the reaction product used in one embodiment of the present invention, Fig. 2 is a voltage-current characteristic diagram of a ZnO element according to an embodiment of the first invention, and Fig. 3 is a A graph showing the changes in V, 1 mA/mm, and α with respect to the heat treatment temperature of the 2nO element, Fig. 4 is a graph showing the leakage current increase rate with respect to opening when energized in the ZnO element, and Fig. 5 is a graph showing the change in V, 1 mA/mm, and α with respect to the heat treatment temperature of the ZnO element. O
V2 when the content ratio of 1 is changed, 5KA/V,
1yy+A and α, FIG. 6 is a graph showing the voltage - of the ZnO device according to an embodiment of the second invention, and FIG. 7 is a graph showing the voltage v7. A graph showing the rate of increase in breeding current with respect to time, FIG. 8 shows At in the second invention,
0. Alternatively, it is a graph showing α when each content ratio of zinc borosilicate glass is changed. ('/.) Figure 3: How to treat warm skin C) Figure 4: Figure 5

Claims (2)

[Claims] (1) The first layer consists of 0.1 to 5 mol of manganese oxide, 0.1 to 5 mol % of antimony oxide, 0.1 to 5 mol of chromium oxide, 0.2/1000 to 2 V of aluminum oxide, and the balance consisting of zinc oxide. In terms of ingredients, chromium oxide,
0.2 to 20% by weight of a second component obtained by completely calcining a mixture consisting of at least one of zinc oxide, cobalt oxide, and manganese oxide, and lead oxide and r)-antimony oxide is added, and the mixture is calcined. ``Voltage nonlinear resistor, which is characterized by being connected to (2) Manganese oxide 0.1-5 mol%, antimony oxide 0.1-5 mol%, chromium oxide 0.1-5 mol%,
E version 7 #Mi = Ram 0, 2/1000-2Q/1
A mixture consisting of a first component consisting of 000 moss, the remainder consisting of zinc oxide, zinc borosilicate glass, one or more of chromium oxide, zinc oxide, cobalt oxide and manganese oxide, and lead oxide and antimony oxide. The second component obtained by completely calcining the borosilicate salivary glass having a composition of 0.01.
A voltage non-linear resistor characterized in that it is formed by mixing 5-5-layered powder, 0.2 to 20% by weight of a second component, and the remainder being the first component, and sintering the mixture.