KR100605531B1 - Dysprosia-doped Praseodymia-based Zinc Oxide Varistors And The Manufacturing Method - Google Patents

Abstract

The present invention basically relates to a praseodymia-based zinc oxide varistor added with disprocia (Dy ₂ O ₃ ), more specifically zinc oxide (ZnO), praseodymia (Pr ₆ O ₁₁ ), By adding disprocia (Dy ₂ O ₃ ) to a zinc oxide varistor composed of cobalt oxide (CoO), chromium oxide (Cr ₂ O ₃ ), etc., the microstructure sintered density is 5.50 g / cm ³ or more in a predetermined sintering process. The present invention relates to a praseodymia zinc oxide varistor added with disprocia (Dy ₂ O ₃ ) capable of producing a varistor having an electrical dielectric loss factor of 5.0% or less, and a method of manufacturing the same.

This is not only the composition is different from the conventional bismuth (Bi) varistors, but also has the advantage of the varistor characteristics, and compared with the conventional praseodymia system, not only the varistor characteristics are excellent but also the characteristics of the next generation is less The advantage is that it can provide a varistor.

Zinc Oxide Varistor, Praseodymia, Disproscia, Nonlinear Index, Leakage Current

Description

Dysprosia-doped Praseodymia-based Zinc Oxide Varistors And The Manufacturing Method}             

1 is a flowchart illustrating a method for preparing praseodymia zinc oxide varistor to which disprocia (Dy ₂ O ₃ ) is added according to the present invention.

Figures 2a to 2d are nonlinear index and leakage when adjusting the sintering time and cobalt oxide during the preparation of the Praseodymia zinc oxide varistor added to the disprocia (Dy ₂ O ₃ ) according to the present invention, respectively This graph shows the electrical characteristics of current, dielectric loss factor and density.

The present invention basically relates to a praseodymia-based zinc oxide varistor added with disprocia (Dy ₂ O ₃ ), more specifically zinc oxide (ZnO), praseodymia (Pr ₆ O ₁₁ ), By adding disprocia (Dy ₂ O ₃ ) to a zinc oxide varistor composed of cobalt oxide (CoO), chromium oxide (Cr ₂ O ₃ ), etc., the microstructure sintered density is 5.50 g / cm ³ or more in a predetermined sintering process. Varistors having an electrical dielectric loss coefficient of 5.0% or less can be produced, and this is not only fundamentally different in composition from bismuth (Bi) varistors, but also has superior varistor characteristics, compared with conventional praseodymia series. the display also Pro cyano (Dy ₂ O ₃₎ is added to the praseodymia-based zinc oxide Bari has the advantage that the varistor characteristic to provide the next generation of the varistor is less change in characteristics as well as excellent It relates to the emitter and its manufacturing method.

At present, the miniaturization, integration, and high-density mounting of electronic components, including advanced semiconductor components, which are inserted into electrical, electronic, information communication, and control systems, are being performed. However, the greater the degree of integration of semiconductors, the narrower the line width of the circuits inside the semiconductors, and the more conductive materials are used to operate at low voltages, which results in a lower short circuit. In one system, the withstand voltage is weakened, and accordingly, the frequency of failures such as the destruction or malfunction of the semiconductor device is increasing with respect to the same surge.

In addition, inductive lightning surges that invade along power lines or communication lines of devices, electrostatic discharges (ESD), and on / off surges that occur when machines are turned on or off Surge) and lightning surges caused by natural phenomena such as lightning and thunderbolts are fast-acting impulse surges, which account for a high proportion of malfunctions in today's digital devices.

Surge Absorber is an effective means to protect electronic devices from various surges as described above, and its core element is a variable resistance part that changes according to the voltage and current across the electrode and shows nonlinear resistance characteristics. It is a varistor. Representative among the varistors is a zinc oxide (ZnO) varistor. The zinc oxide varistors are widely used in overvoltage suppression circuits in various voltage and current ranges from small to large capacities.

In the voltage-current characteristics of a conventional zinc oxide varistor, the material causing the varistor characteristic is bismuth (Bi) oxide, which is excellent in the voltage-current characteristic and currently occupies most of the commercial varistors.

However, the zinc oxide varistor composed of the bismuth oxide has some disadvantages as follows. Firstly, ceramic varistors are inherently sintered at high temperatures, and so-called bismuth-based varistor ceramics to which bismuth oxides are added have a high tendency of volatilization of bismuth oxides at high temperature, thereby causing problems in varistor reproducibility. Second, bismuth-based varistor ceramics Easily reacts with other oxides to produce various electrically unnecessary phases, and the phases are located at the grain boundaries, so the absorbing capacity tends to be lowered due to the reduction of the effective grain area. At the same time to have the disadvantage that more than 10 additives are required.

A method for overcoming such a conventional problem is a method of manufacturing a so-called praseodymia-based zinc oxide varistor having a new additive additive praseodymia to a zinc oxide varistor. The praseodymia zinc oxide varistor has only two microstructural formation phases, and thus has a simple phase structure, a large grain boundary area, high surge absorption capacity, and excellent stability of varistors with five compositions. Will.

However, the praseodymia-based zinc oxide varistor also has some disadvantages. First, the amount of cobalt oxide, which is a nonlinear improvement oxide, in the composition is added as about 4 to 10 times higher than other additives, which is pointed out as a problem in terms of cost, and second, a problem in that the change in electrical and physical properties is somewhat large. Is holding.

In order to solve the above problems, the present invention has been proposed, and an object of the present invention is to consist of a five-component oxide in which a main component zinc oxide and essential subcomponent praseodymia, cobalt oxide, and chromium oxide are added to disprocia. To solve the shortcomings of Praseodymia Zinc Oxide Varistor, it is possible to implement varistors with excellent electrical characteristics and less change of characteristics.                         

In the present invention, if any one of the above-mentioned subcomponents is not added, the varistor characteristics deteriorate and entail a large characteristic change. If praseodymia is not added among the four subcomponents, the varistor characteristic itself does not appear, which is the most important additive among the subcomponents. In addition, if the cobalt oxide is not added, the varistor properties are very deteriorated, and therefore, it is a subcomponent that must be added. In addition, if chromium oxide is not added, a nonlinear index of about 35 is obtained depending on the sintering conditions, but improvement in characteristics is required. Varistors composed of components other than dysprosia are difficult to apply in terms of microstructure and electrical properties.

Therefore, the present invention provides excellent varistor characteristics and direct current by controlling the addition amount of disprocia and the addition amount of cobalt oxide to produce a fine structural density of 5.5 g / cm ³ or more and an electrical dielectric loss factor of 5.0% or less in a predetermined sintering process. The purpose of the present invention is to implement a praseodymia zinc oxide varistor having low characteristic change against accelerated deterioration stress.

In order to achieve the above object, the present invention proposes a praseodymia zinc oxide varistor to which disprocia (Dy ₂ O ₃ ) is added.

Varistors according to the present invention, the main component is 82.0 ~ 98.499 mol% zinc oxide (ZnO), 0.5 mol% praseodymia (Pr ₆ O ₁₁ ), an additive, 0.5 ~ 3.0 mol% cobalt oxide (CoO) , 0.5 mol% of chromium oxide (Cr ₂ O ₃ ), 0.001 to 4.0 mol% of a five-component composition formed by combining a (Dy ₂ O ₃ ) characterized in that it comprises a composition.

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The present invention provides a method for preparing a praseodymia based zinc oxide varistor added with dysprocia (Dy ₂ O ₃ ), comprising: weighing zinc oxide, praseodymia, cobalt oxide, chromium oxide and dysprosia; Ball milling the weighed composition, followed by addition of an aqueous solution to uniformly mix to calcin the dried powder; Making and sintering the composition into a shaped body of a desired shape, and then polishing both sides of the sintered sintered body; And applying a silver electrode to the polished sintered body, and carrying out a package treatment.

1 is a flowchart illustrating a method for producing praseodymia zinc oxide varistor to which disprocia (Dy ₂ O ₃ ) is added according to the present invention.

First, the composition is weighed so as to have a composition ratio of 82 to 98.499 mol% of zinc oxide, 0.5 mol% of praseodymia, 0.5 to 3.0 mol% of cobalt oxide, 0.5 mol% of chromium oxide, and 0.001 to 4.0 mol% of disprocia (S102). Subsequently, 2-5 wt% of the PVA aqueous solution as a binder is added to the weighed raw material powder to be uniformly mixed (S104), and then the ball mill is dried at 700-750 ° C. for 1 to 2 hours. (S106).

After the composition is assembled using a 100-320 mesh body to form a molded body of the desired shape under a pressure of 350 ~ 1000 kg / cm ² (S108). At this time, the heating rate is 240 ℃ / hr, the cooling rate is 120 ~ 480 ℃ / hr sintered for 1 to 3 hours at 1250 ~ 1350 ℃ (S110). If sintered at 1250 ℃ or less, the varistor properties are good, but it is not possible to obtain a dense sintered body, and the resulting change is severe, and if sintered at 1350 ℃ or more, the sintered body is dense but the varistor characteristics are significantly reduced, and thus sintered at the correct temperature It should be possible.

Both surfaces of the sintered sintered body sintered in the above process are polished with abrasives # 1000 to 2000, so that the variation in thickness is 0.5 μm (S112). The electrode is not applied to the polished surface from 0.2 to 0.3 mm from the edge, and the silver electrode is subsequently coated to heat-resistant at 600 ° C. for 10 minutes to be in ohmic contact (S114). Finally, the package process (S116) is completed to complete the above process.

Hereinafter, the electrical characteristics of the most preferred embodiments of the present invention will be described in detail with reference to the table below. The following examples are tables of current-voltage characteristics of praseodymia based zinc oxide varistors added with disprocia (Dy ₂ O ₃ ) prepared according to the present invention using Kiethley 237 equipment.

The varistor voltage V _1mA is a characteristic parameter related to the current-voltage characteristic, and is a voltage when a current of 1 mA / cm ² flows, and the nonlinear index α is I = kV ^α (where I is current, V is voltage, and k is proportional). Constant) and the electric fields corresponding to 1 mA / cm ² , 10 mA / cm ^2, and this current, respectively, were calculated from α = 1 / (E _10mA -E _1mA ) at E _1mA and E _10mA . Leakage current I _l was defined as the current flowing during 80% of the varistor voltage is applied. The electrical dielectric loss factor (tanδ), which has a significant effect on the stability, was measured at 1 kHz using an LCR meter.

Example 1

In Example 1, the varistor was prepared by fixing cobalt oxide at 1.0 mol% and changing the composition of disprocia. That is, 94.0-98.499 mol% of zinc oxide, 0.5 mol% of praseodymia, 1.0 mol% of cobalt oxide, 0.5 mol% of chromium oxide, and 0-4.0 mol% of disprosia are weighed out to prepare a mixture molded body. It is sintered at 1350 ° C. for 1 hour and then mirror processed to a thickness of 1 mm. The electrode is applied to the surface of the mirror-finished sintered compact, subjected to resistive contact by heat treatment, and then packaged.

The varistor element (V _1mA ) was manufactured by the above-described method. And nonlinear index (α), leakage current (I ₁ ), electrical dielectric loss coefficient (tanδ), etc. were measured and shown in Table 1.

TABLE 1

   device(#)    Sintering time (h)  Additive oxide  Electrical characteristics Density (g / cm ³ )  Pr Co Cr Dy V _1mA (V / mm)  α I _l (μA)  tanδ (%)  1 (comparative example)        One  0.5 1.0 0.5 0.0  39.4  4.5  87.9  34.2  5.5  2  0.5 1.0 0.5 0.5  223.8  66.6  1.2  3.0  5.4  3  0.5 1.0 0.5 1.0  345.4  34.2  3.7  10.5  4.6  4  0.5 1.0 0.5 2.0  436.6  37.0  2.4  7.8  4.4  5  0.5 1.0 0.5 4.0  644.9  60.2  0.8  16.1  4.3

Referring to the above table, the nonlinear index (α) is increased in all cases in which the disprocia is added, compared to the comparative example (Device No. # 1) without adding the disprocia, and the leakage current (I ₁ ) and Since the electrical dielectric loss factor (tan δ) is reduced, it is possible to manufacture a varistor device having improved electrical characteristics by adding disproscia.

The nonlinear index (α) has the highest value and the dielectric loss factor (tanδ) has the lowest value and the density (g / cm ³ ) when the disprocia is 0.5 mol% (device number # 2). Also, it has the highest value, so it has the best electrical characteristics as a varistor.

In addition, in the region of 1.0 mol% or more, the nonlinear index (α) is getting larger as the amount of Dysprossia added, and the leakage current (I ₁ ) and density (g / cm ³ ) are generally reduced. Doing. Accordingly, it can be seen that the electrical and physical properties such as nonlinear index (α), leakage current (I ₁ ), and density (g / cm ³ ) can be changed as desired according to the change in the amount of disprocia added.

Example 2

In Example 2, a varistor was prepared by fixing cobalt oxide to 2.0 mol% and changing the composition of disprocia. That is, it was weighed so as to have a composition ratio of 93.0 to 99.0 mol% of zinc oxide, 0.5 mol% of praseodymia, 2.0 mol% of cobalt oxide, 0.5 mol% of chromium oxide, and 0 to 4.0 mol% of dysprosia, Produce varistors according to the process.

The varistor element (V _1mA ) was manufactured by the above-described method. And nonlinear index (α), leakage current (I ₁ ), electrical dielectric loss coefficient (tanδ), and the like are measured and shown in Table 2.

TABLE 2

   device(#)    Sintering time (h)  Additive oxide  Electrical characteristics Density (g / cm ³ )  Pr Co Cr Dy V _1mA (V / mm)  α I _l (μA)  tanδ (%)  6 (comparative example)        One  0.5 2.0 0.5 0.0  45.0  5.0  85.5  34.3  5.5  7  0.5 2.0 0.5 0.5  181.9  55.3  0.1  2.3  5.5  8  0.5 2.0 0.5 1.0  338.3  58.6  0.7  6.3  5.2  9  0.5 2.0 0.5 2.0  480.9  48.8  1.1  9.2  4.6  10  0.5 2.0 0.5 4.0  678.0  75.0  0.6  14.9  4.5

Referring to the above table, as in Example 1, the nonlinear index (α) increases in all cases in which the disprocia is added, compared to the comparative example in which no disprocia is added (Device No. # 6), and the leakage current is increased. Since (I ₁ ) and the electrical dielectric loss factor (tan δ) are reduced, it is possible to manufacture a varistor device having improved electrical characteristics by adding dysprossia.

When the disprocia is 4.0 mol% (device number # 10), the nonlinear index (α) has the highest value and the best electrical characteristics. However, the leakage current (I ₁ ), the electrical dielectric loss coefficient (tan δ) and the density (g / cm ³ ) have the best electrical properties when the disprocia is 0.5 mol% (device number # 7).

In addition, the nonlinear index (α) is generally increasing in value as the amount of disprocia added increases, and the leakage current (I ₁ ) and density (g / cm ³ ) are generally decreasing in value. Thus, as shown in Table 1, the electrical and physical properties, such as nonlinear index (α), leakage current (I _l ), and density (g / cm ³ ), can be changed as desired according to the change in the amount of disprocia added. Able to know.

Example 3

In Example 3, varistors were prepared by fixing cobalt oxide at 3.0 mol% and changing the composition of disprocia. That is, it was weighed so as to have a composition ratio of 92.0-96.0 mol% of zinc oxide, 0.5 mol% of praseodymia, 3.0 mol% of cobalt oxide, 0.5 mol% of chromium oxide, and 0-4.0 mol% of dysproscia, and the same as in Example 1 Produce varistors according to the process.

The varistor element (V _1mA ) was manufactured by the above-described method. And nonlinear index (α), leakage current (I ₁ ), electrical dielectric loss coefficient (tanδ), and the like, are shown in Table 3.

TABLE 3

   device(#)    Sintering time (h)  Additive oxide  Electrical characteristics Density (g / cm ³ )  Pr Co Cr Dy V _1mA (V / mm)  α I _l (μA)  tanδ (%)  11 (comparative example)        One  0.5 3.0 0.5 0.0  69.9  7.4  74.3  27.7  5.4  12  0.5 3.0 0.5 0.5  143.4  30.7  4.8  5.4  5.5  13  0.5 3.0 0.5 1.0  234.0  49.4  0.5  2.2  5.4  14  0.5 3.0 0.5 2.0  405.3  36.8  2.1  7.9  4.9  15  0.5 3.0 0.5 4.0  595.0  44.5  1.2  18.6  4.5

Referring to the above table, as in Example 1, the nonlinear index (α) increases in all cases in which the disprocia is added, compared to the comparative example in which no disprocia is added (Device No. 11). Since (I ₁ ) and the electrical dielectric loss factor (tan δ) are reduced, it is possible to manufacture a varistor device having improved electrical characteristics by adding dysprossia.

The nonlinear index (α), leakage current (I _l ), electrical dielectric loss factor (tanδ) and density (g / cm ³ ) have the highest electrical characteristics when the disprocia is 1.0 mol% (device number # 13). good. In addition, the nonlinear index (α) and the density (g / cm ³ ) are changed depending on the amount of disprocia added, as in Tables 1 to 2.

On the other hand, compared with Table 1 and Table 2, when only the additive of cobalt oxide increased (1 mol%-> 2 mol%-> 3 mol%) under the same conditions, the nonlinear index (α) decreased, and leakage It can be seen that the current I ₁ is generally increasing in value.

Example 4

In Example 4, the varistor is manufactured by increasing the sintering time and changing the composition ratio of dysprosia. That is, it is weighed so as to have a composition ratio of 93.0 to 97.5 mol% of zinc oxide, 0.5 mol% of praseodymia, 1.0 to 2.0 mol% of cobalt oxide, 0.5 mol% of chromium oxide, and 0 to 4.0 mol% of disprosia. As in Example 1, a varistor was produced with a sintering time of 2 hours.

The varistor element (V _1mA ) was manufactured by the above-described method. And nonlinear index (α), leakage current (I ₁ ), electrical dielectric loss coefficient (tanδ), etc. were measured and shown in Table 4.

TABLE 4

   device(#)    Sintering time (h)  Additive oxide  Electrical characteristics Density (g / cm ³ )  Pr Co Cr Dy V _1mA (V / mm)  α I _l (μA)  tanδ (%)  16 (comparative)        2  0.5 2.0 0.5 0.0  32.7  4.0  92.0  42.1  5.5  17  0.5 1.0 0.5 0.5  179.0  54.8  2.5  2.7  5.5  18  0.5 2.0 0.5 0.5  150.3  46.3  0.3  4.3  5.6  19  0.5 2.0 0.5 1.0  235.6  35.1  0.8  2.7  5.4  20  0.5 2.0 0.5 2.0  372.0  39.4  2.4  5.9  4.7  21  0.5 2.0 0.5 4.0  567.7  57.4  0.9  18.6  4.9

Referring to the above table, as in Example 1, the nonlinear index (α) increases in all cases in which the disprocia is added, compared to the comparative example in which no disprocia is added (Device No. # 16), and the leakage current is increased. Since (I ₁ ) and the electrical dielectric loss factor (tan δ) are reduced, it is possible to manufacture a varistor device having improved electrical characteristics by adding dysprossia.

When the sintering time is 2 hours and the disprocia is 4.0 mol% (device number # 21), the nonlinear index (α) is the highest, but the electrical dielectric loss factor (tanδ) is high, resulting in low stability and density (g / cm ³ ) is also low. On the other hand, device number # 17 and device number # 18 have high nonlinear index (α) and density (g / cm ³ ), and have low electrical dielectric loss coefficient (tanδ) and leakage current (I ₁ ). This is good.

On the other hand, when the sintering time is 2 hours as shown in Tables 1 to 3 where the sintering time is 1 hour, the nonlinear index (α) is generally larger as the amount of disprocia added increases, and the leakage current I ₁ is a value. Becomes smaller. However, with the same additive composition, the sintering time different (Table 2), a nonlinear index (α) becomes small, the leakage current (I _l) as compared it can be seen that the increased.

Example 5

In Example 5, the varistor is produced by changing the sintering time to 0.5 mol% of disprocia. That is, it is weighed so as to have a composition ratio of 96.5 to 97.5 mol% of zinc oxide, 0.5 mol% of praseodymia, 1.0 to 2.0 mol% of cobalt oxide, 0.5 mol% of chromium oxide, and 0.5 mol% of disprocia. The production process is the same as in Example 1, but a varistor is produced with a sintering time of 1 hour to 3 hours.

The varistor element (V _1mA ) was manufactured by the above-described method. And nonlinear index (α), leakage current (I ₁ ), electrical dielectric loss coefficient (tanδ), and the like, are shown in Table 5.

TABLE 5

   device(#)    Sintering time (h)  Additive oxide  Electrical characteristics Density (g / cm ³ )  Pr Co Cr Dy V _1mA (V / mm)  α I _l (μA)  tanδ (%)  1 (comparative example)  One  0.5 1.0 0.5 0.0  39.4  4.5  87.9  34.2  5.5  2    One  0.5 1.0 0.5 0.5  223.8  66.6  1.2  3.0  5.4  7  0.5 2.0 0.5 0.5  181.9  55.3  0.1  2.3  5.5  17    2  0.5 1.0 0.5 0.5  179.0  54.8  2.5  2.7  5.5  18  0.5 2.0 0.5 0.5  150.3  46.3  0.3  4.3  5.6  22    3  0.5 1.0 0.5 0.5  143.5  46.5  3.5  4.7  5.6  23  0.5 2.0 0.5 0.5  126.7  38.2  1.1  5.1  5.6

Referring to the above table, when the sintering time is 3 hours, the dielectric loss coefficient (tan δ) is generally smaller and the density (g / cm ³ ) is larger than that when the sintering time is 1 hour or 2 hours, and the stability is excellent. . However, the nonlinear index α is generally reduced, and the leakage current I ₁ is large.

More specifically, when comparing the nonlinear index according to the sintering time with reference to FIG. 2A, the nonlinear index α is gradually increased as the sintering time is increased (1 hour-> 2 hours-> 3 hours). Decreases (66.6-> 54.8-> 46.5, 55.3-> 46.3-> 38.2) and has a larger nonlinearity index (α) when the amount of cobalt oxide added is 1.0 mol% than when 2.0 mol% is added. have.

In addition, when comparing the leakage current according to the sintering time with reference to Figure 2b, the leakage current (I _l ) is gradually increased as the sintering time (1 hour-> 2 hours-> 3 hours) (1.2) ->2.5-> 3.5, 0.1->0.3-> 1.1), and when the addition amount of the cobalt oxide is 1.0 mol% than it has a larger leakage current (I _l ).

And, when comparing the dielectric loss coefficient according to the sintering time with reference to Figure 2c, the dielectric loss coefficient (tanδ) is gradually increased as the sintering time (1 hour-> 2 hours-> 3 hours) ( 3.0->2.7-> 4.7, 2.3->4.3-> 5.1), comparing the density according to the sintering time with reference to Figure 2d, the density (g / cm ³ ) is increased in the sintering time (1 hour-> 2) The time increases with time (> 3 hours) (5.4->5.5-> 5.6, 5.5->5.6-> 5.6).

As shown in the above various embodiments, the nonlinear index of each device shows various values depending on the composition ratio of the additives. In the above results, when comparing Table 1, Table 2, Table 3, the nonlinear index decreases when only the amount of cobalt oxide added is increased from 1 mol%-> 2 mol%-> 3 mol% under the same conditions, Leakage current generally increases in value.

In addition, referring to Table 5, as the sintering time is increased from 1 hour-> 2 hours-> 3 hours, the nonlinear index decreases and the leakage current increases generally.

In addition, device numbers # 2, # 7, # 12, # 13, # 18, # 19, # 22, and # 23 are relatively high in nonlinearity and density, and have a low dielectric loss coefficient of 5% or less. In addition, the leakage current is also low in the device to which the disprocia is added, which is good electrical characteristics as a varistor. In addition, there are some devices (# 5, # 10, # 21) that have very high nonlinearity, but they are low in density and have a large loss factor.

The stress test results show that the devices with high dielectric loss coefficients and low densities have low stability due to thermal runaway due to transient currents. When the sintering time was 1 hour, the devices (# 2, # 7, # 12) containing 0.5 mol% of disprocia were found to have high density, low dielectric loss coefficient, and excellent stability. In addition, when the sintering time is 3 hours than when the sintering time is 1 hour or 2 hours, the density is higher, the dielectric loss coefficient is low, and the stability is improved.

Except for device # 19, devices with a density of less than 5.5 g / cm ³ exhibited poor stability as a result of stress tests, and devices with a dielectric loss factor of 5.0% or higher even when the density was higher than 5.5 g / cm ³ had a high variation in varistor characteristics. It was great. In view of this, the device having a dielectric loss factor of 5.0% or less and a density of 5.5 g / cm ³ or more has excellent electrical characteristics and stability.

As mentioned above, although this invention was demonstrated in detail using the preferable embodiment, the scope of the present invention is not limited to a specific embodiment, Comprising: It should be interpreted by the attached claim. In addition, those skilled in the art should understand that many modifications and variations are possible without departing from the scope of the present invention.

As described above, the present invention provides a zinc oxide varistor composed of zinc oxide (ZnO), praseodymia (Pr ₆ O ₁₁ ), cobalt oxide (CoO), chromium oxide (Cr ₂ O ₃ ), and the like. The varistor is manufactured by adding Dysprossia (Dy ₂ O ₃ ), which shows high nonlinearity, low leakage current, high nonlinearity and excellent stability. It can be very useful for absorber.

In addition, since the present invention changes the electrical characteristics of the varistor by adjusting the amount of disprocia added, it also has the advantage that the varistor having the desired characteristics can be easily manufactured.

Claims (6)

82.0 ~ 98.499mol% zinc oxide (ZnO) as main component, 0.5mol% praseodymia (Pr ₆ O ₁₁ ) as additive, 0.5 ~ 3.0mol% cobalt oxide (CoO), 0.5mol% chromium oxide Praseodymium-based zinc oxide with a disprocia added, comprising a five-component composition formed by combining (Cr ₂ O ₃ ) and 0.001 to 4.0 mol% of disprocia (Dy ₂ O ₃ ). Varistor. delete delete delete delete delete

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