JP3067374B2 - Voltage non-linear resistor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voltage non-linear resistor, more specifically, zinc oxide (Zn) used as an overvoltage protection element.
O) as a main component.

[0002]

2. Description of the Related Art Heretofore, varistors containing silicon carbide (SiC), selenium (Se), silicon (Si) or ZnO as a main component have been used for the purpose of overvoltage protection of electronic equipment and electric equipment. Above all, varistors and arrester elements containing ZnO as a main component generally have characteristics such as a low limiting voltage and a large voltage non-linear index.
For this reason, it is suitable for protection against overvoltage of a device composed of a device having a small overcurrent withstand capability such as a semiconductor device, and has been widely used in place of a varistor made of SiC. It is also widely used as an arrester element for the purpose of protecting power equipment.

On the other hand, rare earth containing ZnO as a main component
0.08-5.0 atomic% of the class elements and cobalt (Co)
0.1 to 10.0 atomic%, magnesium (Mg), cal
At least one of the calcium (Ca) is 0.01-5.
0 atomic%, potassium (K), cesium (Cs), rubizi
At least one of the metals (Rb) is 0.01 to 1.0.
Atomic%, chromium (Cr) 0.01 to 1.0 atomic%,
5 × 10 urine (B) ^-Four~ 1 × 10^-1Atomic%, aluminum
(Al), gallium (Ga), indium (In)
At least one of them is 1 × 10^-Four~ 5 × 10^-2atom%
Voltage non-linear resistor manufactured by adding and firing
Has excellent voltage non-linearity, surge withstand capability,
Is described in Japanese Patent Publication No. 1-25205.
Have been.

In addition, praseodymium (Pr) containing ZnO as a main component in an amount of 0.1 to 5.0 atomic% and cobalt (C
o) is 0.5 to 5.0 atomic%, potassium (K), cesium (Cs), and rubidium (Rb) are at least two elements in a total amount of 0.06 to 0.6 atomic%, and chromium (Cr) is 0.0
JP-B-62-14924 describes that a voltage non-linear resistor produced by adding 5 to 0.5 at% and firing is excellent in voltage non-linearity.

[0005]

However, such an electric power
The pressure non-linear resistor still has the following problems. Electric
The pressure non-linear resistor has a unit thickness when a current of 1 mA flows.
Per unit voltage [hereinafter, V_1mA/ T (V / mm)]
Surge energy absorption capacity per unit volume [hereinafter, allowable
Energy (KJ / cm^Three)]
I have to. However, V_1mAIt is allowed to increase / t
Since the energy capacity decreases, for example, change the firing conditions, etc.
By suppressing the growth of particles,_1mA/ T is
It is about 200 V / mm. But for example lightning arrester
When using it for small applications such as reducing the height
From the standpoints of molding and cost reduction, V_1mA/ T is 3
It is desired to be at least 00 V / mm. Therefore,
Composition of voltage nonlinear resistor disclosed in Japanese Patent Publication
And niobium (Nb) to Nb_TwoO_FiveIn the powder of Anne
Chimon (Sb) to Sb_TwoO_ThreeIn powder or tangs
WO for Ten (W) _ThreeSmall amounts of each powder.
And V_1mA/ T is as high as 300 V / mm or more
be able to. However, tolerable energy and manufacturing yield
As for, it is still not satisfactory. It is the next reason
It depends. Nb, Sb or W is Nb_TwoO_FivePowder, S
b_TwoO_ThreePowder or WO_ThreeWhen adding a small amount of powder, the voltage
Weak point where the resistance inside the nonlinear resistor becomes locally low.
And the current is concentrated here.
As a result, the manufacturing yield decreases. Weak points are caused by mixing raw materials
Nb in the process_TwoO_FivePowder, Sb_TwoO_ThreePowder or WO_Threepowder
This is because the powder is not uniformly dispersed, and Nb, Sb or
Part of the W aggregates have low resistance. When a small amount of Nb, Sb or W is added, V_1mA/ T
Can be increased, but when added in large amounts, V_1mA/ T is
descend. Where Nb, Sb or W aggregates is N
Low resistance as well as adding a large amount of b, Sb or W
It becomes a weak point. The voltage nonlinear resistor at which the weak point occurs is
It is easily destroyed at the weak point by applying a surge.

[0006] The present invention has been made in view of the above-mentioned points, and an object of the present invention is to change Nb, Sb, or W-adding form so that Nb ₂ O ₅ powder, Sb ₂ O ₃
An object of the present invention is to provide a voltage non-linear resistor having a higher allowable energy and a higher production yield than a voltage non-linear resistor obtained by adding a trace amount of powder or WO ₃ powder.

[0007]

In order to solve the above-mentioned problems, a voltage non-linear resistor according to the present invention contains ZnO as a main component, a rare earth element in 0.08 to 5.0 atomic%, and Co in 0.1 to 0.1 atomic%.
0.1 to 10.0 atomic%, at least one of Mg and Ca is 0.01 to 5.0 atomic%, at least one of K, Cs and Rb is 0.01 to 1.0 atomic%, and Cr is 0.1 to 1.0 atomic%. 01
~ 1.0 at%, B is 5 × 10 ^-4 to 1 × 10 ^{-1 at} %,
At least one of Al, Ga, and In is 1 × 10 ⁻⁴ to
5 × 10 ⁻² atomic%, one of Nb, Sb or W, Nb is an aqueous solution of niobium oxalate [Nb (HC ₂ O ₄ ) ₅ ], and Sb is potassium antimonyl potassium tartrate hemihydrate. [C ₂ H ₂ (OH) ₂ (COOK) CO ₂ · SbO
· 1 / 2H ₂ with an aqueous solution of O], W are each 1 × 10 ^-3 to 5 with an aqueous solution of potassium tungstate [K ₂ WO _4]
It was added and fired in the range of × 10 ^-2 atomic%.

[0008] As another means, ZnO as a main component, Pr is 0.08 to 5.0 atomic%, and Co is 0.1 to 1 atomic%.
0.0 at%, K at 0.05 to 0.5 at%, Cr at 0.05 to 0.5 at%, Nb, Sb or W, Nb being niobium oxalate [Nb (HC
₂ O ₄₎ with an aqueous solution of _5], Sb tartrate antimony Le potassium hemihydrate _{[C 2 H 2 (OH)} 2 (COOK)
CO ₂ .SbO.1 / 2H ₂ O], and W is an aqueous solution of potassium tungstate [K ₂ WO ₄ ], added in the range of 1 × 10 ^{−3 to} 5 × 10 ⁻² atomic%, and fired. Things.

[0009]

As described above, in the voltage non-linear resistor of the present invention, Nb is further added to the components of the voltage non-linear resistor disclosed in Japanese Patent Publication No. 1-25205 described above with an aqueous solution of niobium oxalate. Or adding Sb as an aqueous solution of potassium antimonyl tartrate hemihydrate, or
Is added in an aqueous solution of potassium tungstate, or Nb is further added to the component of the voltage nonlinear resistor disclosed in the above-mentioned JP-B-62-14924, in an aqueous solution of niobium oxalate, or Sb is added. Is added in an aqueous solution of potassium antimonyl tartrate hemihydrate, or W is added in an aqueous solution of potassium tungstate, so that Nb, Sb or W can be uniformly dispersed and mixed. Nb, Sb as in the case of adding with ₂ O ₅ powder, Sb ₂ O ₃ powder or WO ₃ powder.
Or W does not aggregate. Therefore, a sintered body having a small grain size is formed by suppressing grain growth during firing, the grain boundary layer per unit thickness is increased, and a voltage nonlinear resistor having a high V _{1 mA} / t can be obtained. it can. Moreover, the addition of Nb, Sb or W does not degrade the uniformity of the sintered body, and in a high V _{1 mA} / t region, the allowable energy equal to or higher than that of the voltage nonlinear resistor disclosed in the above-mentioned publication. Value can be given, and the yield is also improved.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments. The voltage non-linear resistor according to the present invention is manufactured by firing and sintering a mixture of ZnO and a metal or a compound as an additional component at a high temperature in an oxygen-containing atmosphere. The additional component is added in the form of a metal oxide, but a compound that can be converted into an oxide in the firing step, for example, a carbonate, a hydroxide, a fluoride and a solution thereof, or the like, or a single element may be used. It can be used and converted into an oxide during the firing process.

The voltage non-linear resistor according to the present invention is ZnO.
Add Nb to niobium oxalate [Nb (HC
₂ O ₄ ) ₅ ], Sb is potassium antimonyl tartrate hemihydrate [C ₂ H ₂ (OH) ₂ (COOK) C
An aqueous solution of O ₂ .SbO.1 / 2H ₂ O] and W is an aqueous solution of potassium tungstate [K ₂ WO ₄ ], and any one of these is added. And calcined at 500 to 1000 ° C. for several hours in the air before firing, then pulverize the calcined material sufficiently to form a predetermined shape, It can be manufactured by firing at a temperature of about 1400 ° C. for several hours. If the firing temperature is lower than 1100 ° C., the sintering is insufficient and the characteristics are unstable. At a temperature higher than 1400 ° C., it is difficult to obtain a homogeneous sintered body, voltage non-linearity is reduced, and reproducibility such as control of characteristics is difficult. Therefore, it is difficult to obtain a practical product.

Next, a specific example of the voltage non-linear resistor according to the present invention will be described. Example 1 ZnO powder was mixed with Pr ₆ O ₁₁ , MgO, K ₂ CO ₃ , and Cr.
₂ O ₃ , B ₂ O ₃ , and Al ₂ O ₃ powders, and further a 5% aqueous niobium oxalate solution were added thereto in an amount corresponding to a predetermined atomic% described in Tables 3 and 4 below. After sufficient mixing, the mixture was calcined at 500 to 1000 ° C. for several hours. Next, the calcined product is sufficiently pulverized, and a binder is added thereto to obtain a 17 mm diameter.
It was press-formed into a disk having a diameter of 1 mm and fired in air at 1100 to 1400 ° C for 1 hour to obtain a sintered body.

In addition, for comparison, Nb was added using Nb ₂ O ₅ powder in an amount corresponding to a predetermined atomic% described in Tables 1 and 2 below. Thus, a sintered body was produced. The sintered body obtained in this way has a thickness of 2
The sample was polished to a thickness of 2 mm, and an electrode was baked on the surface of the sample to form a device. The electrical characteristics of the device were measured. As the electrical characteristics, a voltage between electrodes of _{1 mA} when a current of 1 mA is applied to the element, a square wave current of 2 ms width applied 20 times, and a current value free from penetration breakdown and creepage breakdown, and a limit at that time The allowable energy was determined from the voltage.

When the composition of the voltage non-linear resistor is variously changed, the measurement results of the electric characteristics corresponding to the composition are shown in Tables 1 to 3.
The results are shown in Table 4. The composition shown in Tables 1 to 4 is represented by atomic% calculated from the ratio of the number of atoms of the additive element to the total number of atoms of each component metal element in the blended raw materials. In Tables 1 to 4, V _1mA per unit thickness, V _1mA / t, is used instead of V _1mA , and the allowable energy ratio is described instead of the allowable energy. The allowable energy ratio is a ratio to the allowable energy value when V _1mA / t in the voltage non-linear resistor described in the above-mentioned publication is approximately 200 V / mm.

[0015]

[Table 1]

[0016]

[Table 2]

[0017]

[Table 3]

[0018]

[Table 4]

As described above, Tables 1 and 2 are provided for comparison with the present invention, and are shown in Table 1 for sample N.
o. 1 and Sample No. 2, Pr, Co, Mg, ZnO
It corresponds to a conventional voltage non-linear resistor manufactured by adding only K, Cr, B, and Al. 1 and Sample No. No. 2 has different firing conditions. That is, the sample No. No. 2 is a sample No. Bake at a temperature lower than 1, V _1mA
/ T is a value of 300 V / mm or more. However, when comparing the allowable energy ratio, if you set the V _{1 m A} / t over 300 V / mm, the allowable energy is greatly reduced, it can be seen that not suitable for practical use. Further, the sample No. No. 3 to sample no. 24, and Table 2
Sample No. 25-Sample No. 46 is Nb ₂ O ₅
This corresponds to a voltage non-linear resistor produced by adding a powder of the above.

When V _{1 mA} / t is set to 300 V / mm or more, the voltage non-linear resistor having an allowable energy equal to or more than that when V _{1 mA} / t is 200 V / mm is shown in Table 1 as N
No. b was added as a powder of Nb ₂ O ₅ , 4 ~
7, No. 10-13, No. 16-18, No. 21
No. 23 to Table 2, from Table 2, 26-28, no. 31-3
4, No. 37-40, No. 43 to 45.

Further, among the samples according to the present invention in which Nb was added using a 5% aqueous niobium oxalate solution, V _{1 mA} / t showed 300 V / mm or more, which was equivalent to the case where Nb was added as Nb ₂ O ₅ powder. The voltage non-linear resistor having the above allowable energy is shown in Table 3 from Sample No. 48-51, no.
54-57, No. No. 60-62, no. No. 65 to 67, and from Table 4 70-72, No. 75-78, No. 8
No. 1-84, No. 87-89.

When the results of Tables 3 and 4 are combined, the addition amounts of the respective sub-components suitable for the voltage non-linear resistor of the present invention are as follows: Pr is 0.08 to 5.0 atomic% and Co is 0.1 to 0.1 atomic%. 10.0 atomic%, Mg is 0.01 to 5.0 atomic%, K is 0.01 to
1.0 at%, Cr is 0.01 to 1.0 at%, B is 5
× 10 ^-4 to 1 × 10 ^-1 atomic%, Al is 1 × 10 ^{-4 to} 5 ×
It can be seen that 10 ^-2 atomic% and Nb is in the range of 1 × 10 ^{−3 to} 5 × 10 ^-2 atomic%.

As described above, the voltage non-linear resistor according to the present invention is characterized in that an appropriate amount of Pr, Co, Mg,
By adding an appropriate amount of Nb as an aqueous solution to a composition system containing K, Cr, B, and Al, V _1mA / t is 300
Even in a high region of V / mm or more, excellent surge energy absorbing ability can be provided. This is because Zn
O, Pr, Co, Mg, K, Cr, B, Al and N
b can be achieved only when an appropriate amount of each of b is present. When these subcomponents are added alone, the voltage non-linearity is extremely poor, almost only ohmic characteristics are obtained, and it is impossible to put to practical use. is there.

In this embodiment, only Pr is shown as a rare earth element to be added as an auxiliary component, but a rare earth element other than Pr may be used. Mg is also Ca or Mg and Ca simultaneously added, K is additionally Cs or Rb, or K, Cs, Rb is simultaneously added, and Al is Ga or In or Al, Ga, In. May be added simultaneously. It has been separately confirmed by experiments that the addition of Nb, which is the main feature of the present invention, can provide the same effect as described above even in such a composition system.

Example 2 Pr ₆ O ₁₁ , CO ₃ O ₄ , K ₂ CO ₃ ,
Cr ₂ O ₃ powder and a 5% aqueous niobium oxalate solution were further added thereto in an amount corresponding to a predetermined atomic% shown in Table 6 below, and after sufficient mixing, 500 to 1000
Calcination was performed at ℃ for several hours. Next, the calcined product is sufficiently pulverized, a binder is added thereto, and a pressure is formed into a disk having a diameter of 17 mm.
It was fired in air at 1100-1400 ° C. for 1 hour to obtain a sintered body. In addition, Nb is replaced with Nb for comparison.
Using a powder of ₂ O ₅ , it was added in an amount corresponding to a predetermined atomic% described in Table 5 below, and a sintered body was produced in the same manner. The sintered body obtained in this manner is polished into a sample having a thickness of 2 mm, and an electrode is formed on the surface by burning the electrode.
The electrical characteristics of the device were measured. As the electrical characteristics, the voltage between electrodes V _1mA when a current of 1 mA flows through the element, 2
A square wave current having a width of ms was applied 20 times, and the allowable energy was obtained from the current value without penetrating breakdown and creepage breakdown and the limiting voltage at that time.

When the composition of the voltage non-linear resistor is variously changed, the measurement results of the electrical characteristics corresponding to the various compositions are shown in Table 5 below.
The results are shown in Table 6. The composition shown in Tables 5 and 6 is represented by atomic% calculated from the ratio of the number of atoms of the additive element to the total number of atoms of each component metal element in the blended raw materials. In Tables 5 and 6, V _1mA per unit thickness V _1mA / t is used instead of V _1mA , and the allowable energy ratio is described instead of the allowable energy. The allowable energy ratio is a ratio to the allowable energy value when V _1mA / t in the voltage non-linear resistor described in the above-mentioned publication is approximately 200 V / mm.

Table 5 is provided for comparison with the present invention. 1 and Sample No. 2 is
It corresponds to a conventional voltage nonlinear resistor manufactured by adding only Pr, Co, K, and Cr to ZnO. 1 and Sample No. No. 2 has different firing conditions. That is, the sample No. No. 2 is a sample No. By firing at a temperature lower than 1, V _{1 mA} / t is 300 V / mm or more. However, comparing the allowable energy ratios, it can be seen that when V _{1 mA} / t is set to 300 V / mm or more, the allowable energy is greatly reduced and cannot be put to practical use. In addition, the sample No. No. 3 to sample no.
29 corresponds to a voltage non-linear resistor manufactured by adding Nb as a powder of Nb ₂ O ₅ .

[0028]

[Table 5]

[0029]

[Table 6]

When V _{1 mA} / t is set to 300 V / mm or more, the voltage non-linear resistor having an allowable energy equal to or more than that when V _{1 mA} / t is 200 V / mm is shown in Table 5 by N
No. b was added as a powder of Nb ₂ O ₅ , 4 ~
8, No. Nos. 11 to 13; 16-18, No. 21
~ 23, No. 26 to 28.

Of the samples to which Nb was added using a 5% aqueous niobium oxalate solution, V _{1 mA} / t was 300 V / m
m from Table 6, the voltage non-linear resistor having the allowable energy equal to or higher than that of the case where Nb is added as Nb ₂ O ₅ powder is shown in Table 6 from Sample No. No. 32-37, no. 40-46,
No. 49-51, No. 54-56, No. 59-6
It is one.

When the results in Table 6 are combined, it is clear that the voltage
The addition amount of each sub-component suitable for the linear resistor is such that Pr is 0.0
8 to 5.0 atomic%, Co is 0.1 to 10.0 atomic%, K
Is 0.05-0.5 atomic%, Cr is 0.05-0.5 atom
Child% and Nb is 1 × 10 ^-3~ 5 × 10^-2Atomic% range
It turns out that it is an enclosure.

Example 3 Pr ₆ O ₁₁ , MgO, K ₂ CO ₃ , and Cr were added to ZnO powder.
₂ O ₃ , B ₂ O ₃ , and Al ₂ O ₃ powders, and further, an aqueous solution of 3% potassium antimonyl tartrate hemihydrate were added to a predetermined atomic percentage shown in Tables 9 to 10 below. was added in an amount corresponding to, sintered was prepared in the same manner as in example 1, and separately for comparison to this, the Sb Sb ₂
A sintered body prepared by adding O ₃ powder in an amount corresponding to a predetermined atomic% described in Tables 7 and 8 described below was polished into samples each having a thickness of 2 mm. The electrodes were baked to form devices, and the electrical characteristics of each device were measured. As the electrical characteristics, a voltage between electrodes of _{1 mA} when a current of 1 mA flows through the element and a square-wave current of 2 ms width are set to 20.
The allowable energy was determined from the current value without penetrating breakdown and creepage breakdown, and the limiting voltage at that time.

When the composition of the voltage non-linear resistor is variously changed, the measurement results of the electrical characteristics corresponding to the composition are shown in Tables 7 to 7.
The results are shown in Table 10. The composition shown in Tables 7 to 10 is represented by atomic% calculated from the ratio of the number of atoms of the additive element to the total number of atoms of each component metal element in the blended raw materials. In Tables 7 to 10, V _{1 mA} / t, which is V _{1 mA} per unit thickness, is used instead of V _{1 mA} , and the allowable energy ratio is described instead of the allowable energy. The allowable energy ratio is a ratio to the allowable energy value when V _1mA / t in the voltage non-linear resistor described in the above-mentioned publication is approximately 200 V / mm.

[0035]

[Table 7]

[0036]

[Table 8]

[0037]

[Table 9]

[0038]

[Table 10]

As described above, Tables 7 and 8 are listed for comparison with the present invention.
1 and Sample No. 2, Pr, Co, Mg, K, ZnO
It corresponds to a conventional voltage nonlinear resistor manufactured by adding only Cr, B, and Al. 1 and sample N
o. No. 2 has different firing conditions. That is, sample N
o. No. 2 is a sample No. Firing at a temperature lower than 1 V _1mA /
t is a value of 300 V / mm or more. However, comparing the allowable energy ratios, it can be seen that when V _{1 mA} / t is set to 300 V / mm or more, the allowable energy is greatly reduced and cannot be put to practical use. Further, the sample No. No. 3 to sample no. 24, and Table 8
Sample No. 25-Sample No. 46 represents Sb as Sb ₂ O ₃
This corresponds to a voltage non-linear resistor produced by adding a powder of the above.

When V _{1 mA} / t is set to 300 V / mm or more, the voltage non-linear resistor having the allowable energy equal to or more than that when V _{1 mA} / t is 200 V / mm is shown in Table 7 by S
No. b was added as a powder of Sb ₂ O ₃ , 4 ~
7, No. 10-13, No. 16-18, No. 21
No. 23 to Table 8, from Table 8, 26-28, no. 31-3
4, No. 37-40, No. 43 to 45.

Also, among the samples according to the present invention in which Sb was added using an aqueous solution of 3% potassium antimonyl tartrate hemihydrate, V _{1 mA} / t was 300 V / mm or more, and Sb was Nb ₂ O voltage nonlinear resistor having the same or more permissible energy and when added in ₃ powders from Table 9 sample No. 48-51, no. 54-57, No.
No. 60-62, no. No. 65 to 67, and Table 10 70
~ 72, no. 75-78, No. Nos. 81 to 84;
87-89.

Compiling the results of Tables 9 and 10, the addition amount of each subcomponent suitable for the voltage nonlinear resistor of the present invention is Pr
Is 0.08 to 5.0 atomic%, Co is 0.1 to 10.0 atomic%, Mg is 0.01 to 5.0 atomic%, and K is 0.01 to 5.0 atomic%.
1.0 at%, Cr is 0.01 to 1.0 at%, B is 5
× 10 ^-4 to 1 × 10 ^-1 atomic%, Al is 1 × 10 ^{-4 to} 5 ×
It can be seen that 10 ^-2 atomic% and Sb are in the range of 1 × 10 ^{−3 to} 5 × 10 ^-2 atomic%.

As described above, the voltage non-linear resistor according to the present invention is characterized in that ZnO has an appropriate amount of Pr, Co, Mg,
By adding an appropriate amount of Sb as an aqueous solution to a composition system containing K, Cr, B, and Al, V _1mA / t is 300
Even in a high region of V / mm or more, excellent surge energy absorbing ability can be provided. This is because Zn
O, Pr, Co, Mg, K, Cr, B, Al and S
b can be achieved only when an appropriate amount of each of b is present. When these subcomponents are added alone, the voltage non-linearity is extremely poor, almost only ohmic characteristics are obtained, and it is impossible to put to practical use. is there.

Although in Example 3 only Pr was shown as a rare earth element to be added as a subcomponent, a rare earth element other than Pr may be used. Mg is also Ca or Mg and Ca simultaneously added, K is additionally Cs or Rb, or K, Cs, Rb is simultaneously added, and Al is Ga or In or Al, Ga, In. May be added simultaneously. It has been separately confirmed by experiments that even in such a composition system, the addition of Sb, which is the main object of the present invention, can obtain the same effect as described above.

Example 4 Pr ₆ O ₁₁ , CO ₃ O ₄ , K ₂ CO ₃ ,
Cr ₂ O ₃ powder and an aqueous solution of 3% potassium antimonyl tartrate hemihydrate were further added thereto, as shown in Table 12 below.
It was added in an amount corresponding to a predetermined atomic% as described in Example
Sintered was prepared in the same manner as in 2, and separately for comparison to this, the Sb using powder of Sb ₂ O _3, is added in an amount corresponding to a predetermined atomic% as described in the following Table 11 Each of the sintered bodies thus produced was polished into a sample having a thickness of 2 mm, and electrodes were baked on the surface to form elements, and the electrical characteristics of each element were measured. As the electrical characteristics, the voltage between electrodes V _1mA when a current of 1 mA flows through the element, 2 ms
By applying a square wave current having a width of 20 times, the allowable energy was obtained from the current value without penetrating breakdown and creepage breakdown and the limiting voltage at that time.

When the composition of the voltage non-linear resistor is variously changed, the measurement results of the electric characteristics corresponding to the composition are shown in Table 1.
1, shown in Table 12. The composition shown in Tables 11 and 12 is represented by atomic% calculated from the ratio of the number of atoms of the additive element to the total number of atoms of each component metal element in the blended raw materials. Also, Table 11, using the V _1mA / t is V _1mA per unit thickness in place of V _1mA in Table 12, it is marked with the allowable energy ratio instead of the allowable energy. The allowable energy ratio is a ratio to the allowable energy value when V _1mA / t in the voltage non-linear resistor described in the above-mentioned publication is approximately 200 V / mm.

Table 11 is provided for comparison with the present invention. 1 and Sample No. 2
Corresponds to a conventional voltage nonlinear resistor manufactured by adding only Pr, Co, K, Cr to ZnO,
Sample No. 1 and Sample No. No. 2 has different firing conditions. That is, the sample No. No. 2 is a sample No. By firing at a temperature lower than 1, V _{1 mA} / t is 300 V / mm or more. However, comparing the allowable energy ratios, it can be seen that when V _{1 mA} / t is set to 300 V / mm or more, the allowable energy is greatly reduced and cannot be put to practical use. In addition, the sample No. 3 to sample N
o. Numeral 29 corresponds to a voltage non-linear resistor manufactured by adding Sb as a powder of Sb ₂ O ₃ .

[0048]

[Table 11]

[0049]

[Table 12]

When V _{1 mA} / t is set to 300 V / mm or more, the voltage non-linear resistor having an allowable energy equal to or more than that when V _{1 mA} / t is 200 V / mm is shown in Table 11.
In the sample in which Sb was added as a powder of Sb ₂ O ₃ , 4
~ 8, No. Nos. 11 to 13; 16-18, No. 2
Nos. 1 to 23, No. 1; 26 to 28.

Further, Sb was added to 3% antimony potassium tartrate.
Sample added using an aqueous solution of
Chi, V_1mA/ T indicates 300 V / mm or more, and Sb is S
b_TwoO _ThreeEnergy equivalent to or better than that of powder added
Table 12 shows that the voltage non-linear resistor having
o. No. 32-37, no. 40-46, No. 49-5
1, No. 54-56, No. 59 to 61.

When the results shown in Table 12 are combined, the addition amount of each sub-component suitable for the voltage non-linear resistor of the present invention is such that Pr is 0.
08 to 5.0 atomic%, Co is 0.1 to 10.0 atomic%,
K is 0.05-0.5 atomic%, Cr is 0.05-0.5
Atomic% and Sb are in the range of 1 × 10 ^{−3 to} 5 × 10 ⁻² atomic%.

As described above, the voltage non-linear resistor according to the present invention is composed of ZnO and Pr, Co, K, C
By adding an appropriate amount of Sb as an aqueous solution to the composition system containing r, an excellent surge energy absorbing ability can be provided even in a high V _{1 mA} / t region of 300 V / mm or more. This is because PrO, ZnO
This is achieved only when an appropriate amount of each of o, Mg, K, Cr, B, Al and Sb coexists. When these subcomponents are added alone, the voltage nonlinearity is extremely poor.
Since almost only ohmic characteristics are obtained, it is impossible to put it to practical use.

Embodiment 5 Pr ₆ O ₁₁ , MgO, K ₂ CO ₃ , Cr were added to ZnO powder.
₂ O ₃ , B ₂ O ₃ , and Al ₂ O ₃ powders and an aqueous solution of 5% potassium tungstate were further added thereto in an amount corresponding to a predetermined atomic% described in Tables 15 and 16 below. example 1, sintered bodies were prepared in the same manner as in example 3, and separately for comparison to this, the W using powder of WO _3, below the predetermined set forth in tables 13 14 The sintered bodies produced by adding the elements in an amount corresponding to the atomic% were polished into samples each having a thickness of 2 mm, and electrodes were baked on the surfaces thereof to produce devices, and the electrical characteristics of each device were measured. As the electrical characteristics, a voltage between electrodes of _{1 mA} when a current of 1 mA is applied to the element, a square wave current of 2 ms width applied 20 times, and a current value free from penetration breakdown and creepage breakdown, and a limit at that time The allowable energy was determined from the voltage.

When the composition of the voltage non-linear resistor is variously changed, the measurement results of the electrical characteristics corresponding to the composition are shown in Table 13.
To Table 16 below. The composition shown in Tables 13 to 16 is represented by atomic% calculated from the ratio of the number of atoms of the additive element to the total number of atoms of each component metal element in the blended raw materials. In Tables 13 to 16, V _{1 mA} / t, which is V _{1 mA} per unit thickness, is used instead of V _{1 mA} , and the allowable energy ratio is described instead of the allowable energy. The allowable energy ratio is a ratio to the allowable energy value when V _1mA / t in the voltage non-linear resistor described in the above-mentioned publication is approximately 200 V / mm.

[0056]

[Table 13]

[0057]

[Table 14]

[0058]

[Table 15]

[0059]

[Table 16]

As described above, Tables 13 and 14 are based on the present invention.
For comparison, the samples listed in Table 13
No. 1 and Sample No. 2 is Pr, Co, M in ZnO
g, K, Cr, B, Al
It corresponds to a voltage non-linear resistor. 1
And sample No. No. 2 has different firing conditions. That is,
Sample No. No. 2 is a sample No. Firing at a temperature lower than 1
_1mA/ T is a value of 300 V / mm or more.
However, comparing the allowable energy ratios, V _1mA/
When t is set to 300 V / mm or more, the allowable energy
It is understood that the energy is greatly reduced and cannot be put to practical use.
In addition, the sample No. No. 3 to sample no. 24, and
In Table 14, sample No. 25-Sample No. 46 is WO for W_Three
Equivalent to voltage non-linear resistor made by adding powder
Things.

When V _{1 mA} / t is set to 300 V / mm or more, the voltage non-linear resistor having the allowable energy equal to or more than that when V _{1 mA} / t is 200 V / mm is shown in Table 13.
In the sample in which W was added as a powder of WO ₃ , 4-7,
No. 10-13, No. 16-18, No. 21-2
3, from Table 14, 26-28, no. 31-3
4, No. 37-40, No. 43 to 45.

Further, among the samples according to the present invention in which W was added using an aqueous solution of 5% potassium tungstate, V
_From Table 15, the voltage non-linear resistor having _{1 mA} / t of 300 V / mm or more and having an allowable energy equal to or higher than that of the case where W is added as a WO ₃ powder is shown in Table 15. 48-5
1, No. 54-57, No. No. 60-62, no. 65
~ 67, No. from Table 16. 70-72, No. 75-7
8, No. Nos. 81 to 84; 87-89.

When the results of Tables 15 and 16 are combined, the addition amount of each subcomponent suitable for the voltage non-linear resistor of the present invention is P
r is 0.08 to 5.0 atomic% and Co is 0.1 to 10.0.
Atomic%, Mg: 0.01 to 5.0 atomic%, K: 0.01
1.0 to 1.0 atomic%, Cr is 0.01 to 1.0 atomic%, B is 5 × 10 ^-4 to 1 × 10 ^-1 atomic%, and Al is 1 × 10 ^{-4 to} 5
It can be seen that × 10 ⁻² atomic% and W is in the range of 1 × 10 ^{−3 to} 5 × 10 ⁻² atomic%.

As described above, the voltage non-linear resistor according to the present invention is composed of ZnO with an appropriate amount of Pr, Co, Mg,
By adding an appropriate amount of W as an aqueous solution to a composition system containing K, Cr, B, and Al, V _{1 mA} / t becomes 300 V
Even in a high region of / mm or more, excellent surge energy absorbing ability can be provided. This is ZnO
Is achieved only when appropriate amounts of Pr, Co, Mg, K, Cr, B, Al and W are present together.
If these subcomponents are added alone, the voltage non-linearity is extremely poor, and only approximately ohmic characteristics are obtained, making it impossible to use them practically.

In the fifth embodiment, as in the first and third embodiments , only Pr is shown as a rare earth element to be added as an auxiliary component. However, a rare earth element other than Pr may be used. In addition, Mg is added to Ca, or simultaneous addition of Mg and Ca, K
Is the simultaneous addition of Cs or Rb or K, Cs, or Rb, and Al is Ga or In or Al, Ga, I
n may be added simultaneously. It has been separately confirmed by experiments that the addition of W, which is the main feature of the present invention, can provide the same effect as described above even in such a composition system.

[0066] Example 6 ZnO _{powder, Pr 6 O 11, CO 3} O 4, K 2 CO 3,
Cr ₂ O ₃ powder and an aqueous solution of 5% potassium tungstate were further added thereto in an amount corresponding to a predetermined atomic% described in Table 18 below, and the same as in Examples 2 and 4. The sintered body produced and, for comparison, a sintered body produced by adding W using a WO ₃ powder in an amount corresponding to a predetermined atomic% described in Table 17 below. Was polished into a sample having a thickness of 2 mm, and electrodes were baked on the surface to form elements, and the electrical characteristics of each element were measured. As the electrical characteristics, a voltage between electrodes of _{1 mA} when a current of 1 mA is applied to the element, a square wave current of 2 ms width applied 20 times, and a current value free from penetration breakdown and creepage breakdown, and a limit at that time The allowable energy was determined from the voltage.

When the composition of the voltage non-linear resistor was variously changed, the measurement results of the electrical characteristics corresponding to the composition were shown in Table 1.
7, shown in Table 18. The composition shown in Tables 17 and 18 is represented by atomic% calculated from the ratio of the number of atoms of the additive element to the total number of atoms of each component metal element in the blended raw materials. Also, Table 17, using the V _1mA / t is V _1mA per unit thickness in place of V _1mA in Table 18, it is marked with the allowable energy ratio instead of the allowable energy. The allowable energy ratio is a ratio to the allowable energy value when V _1mA / t in the voltage non-linear resistor described in the above-mentioned publication is approximately 200 V / mm.

Table 17 is provided for comparison with the present invention. 1 and Sample No. 2
Corresponds to a conventional voltage nonlinear resistor manufactured by adding only Pr, Co, K, Cr to ZnO,
Sample No. 1 and Sample No. No. 2 has different firing conditions. That is, the sample No. No. 2 is a sample No. By firing at a temperature lower than 1, V _{1 mA} / t is 300 V / mm or more. However, comparing the allowable energy ratios, it can be seen that when V _{1 mA} / t is set to 300 V / mm or more, the allowable energy is greatly reduced and cannot be put to practical use. Further, the sample No. 3 to sample N
o. Numeral 29 corresponds to a voltage non-linear resistor manufactured by adding W as a powder of WO ₃ .

[0069]

[Table 17]

[0070]

[Table 18]

When V _1mA / t is set to 300 V / mm or more, the voltage non-linear resistor having the allowable energy equal to or more than that when V _1mA / t is set to 200 V / mm is shown in Table 17.
In the sample in which W was added as a powder of WO ₃ , 4-8,
No. Nos. 11 to 13; 16-18, No. 21-2
3, No. 26 to 28.

Of the samples to which W was added using an aqueous solution of 5% potassium tungstate, V _{1 mA} / t was 30%.
The voltage non-linear resistor having a permissible energy equal to or higher than that in the case where W is added as a W ₂ O ₃ powder and having a voltage of 0 V / mm or more is shown in FIG. No. 32-37, no. 40
-46, No. 49-51, No. 54-56, No.
59 to 61.

The results of Table 18 are summarized to show that the voltage of the present invention
The addition amount of each sub-component suitable for the nonlinear resistor is such that Pr is 0.
08 to 5.0 atomic%, Co is 0.1 to 10.0 atomic%,
K is 0.05-0.5 atomic%, Cr is 0.05-0.5
Atomic%, and W is 1 × 10 ^-3~ 5 × 10^-2Atomic% range
It turns out that it is an enclosure.

As described above, the voltage non-linear resistor according to the present invention is obtained by adding an appropriate amount of Pr, Co, K, C
By adding an appropriate amount of W as an aqueous solution to the composition system containing r, an excellent surge energy absorbing ability can be provided even in a high V _{1 mA} / t region of 300 V / mm or more. This is because PrO, ZnO
This is achieved only when an appropriate amount of each of o, Mg, K, Cr, B, Al and W coexists. When these subcomponents are added alone, the voltage non-linearity is extremely poor and only an almost ohmic characteristic is obtained. It cannot be obtained and cannot be put to practical use.

[0075]

As described above, as described above, ZnO as a main component, other subcomponents such as rare earth elements, and Nb, S
The voltage non-linear resistor of the present invention obtained by adding one of b and W in the form of an aqueous solution and firing the same has a V _{1 mA} / t of 30.
Nb is Nb ₂ O even in a high region of 0 V / mm or more.
₅ powder, Sb is a Sb ₂ O ₃ powder, and W is a WO ₃ powder, and a surge energy absorbing ability equal to or higher than that of the case where they are added can be obtained. That is, since Nb, Sb or W is added in the form of an aqueous solution, they can be uniformly dispersed in ZnO, so that the voltage non-linear resistor has good uniformity without generating weak points. Yes, the allowable energy is further increased and the production yield is improved. This is extremely effective in reducing the size of equipment to which the voltage non-linear resistor is applied, for example, a lightning arrester and reducing the cost.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References WO 91/9407 (WO, A1) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01C ^7/ 02-7/22

Claims (12)

(57) [Claims] 1. A zinc oxide as a main component, and at least one rare earth element as a subcomponent in a total amount of 0.08 to 5.0.
0 at%, 0.1 to 10.0 at% of cobalt, at least one of magnesium and calcium in a total amount of 0.1 at.
0.01 to 5.0 atomic%, at least one of potassium, cesium and rubidium in a total amount of 0.01 to 1.0 atomic%, chromium of 0.01 to 1.0 atomic%, and boron of 5 × 1
0 ^-4 to 1 × 10 ^-1 atomic%, at least one of aluminum, gallium and indium in a total amount of 1 × 10 ^{-4 to} 5
1 × 10 ^{−3 to} 5 × 10 ⁻² atomic% and niobium in an aqueous solution
A voltage non-linear resistor characterized by being added and fired in a range of × 10 ^-2 atomic%. 2. The voltage nonlinear resistor according to claim 1, wherein niobium is niobium oxalate [Nb (HC ₂ O ₄ ) ₅ ].
A non-linear voltage resistor characterized by being added as an aqueous solution of: 3. Zinc oxide as a main component, and praseodymium as a subcomponent at 0.08 to 5.0 at%, cobalt at 0.1 to 10.0 at%, and potassium at 0.05 to 0.1 at%.
Voltage non-linearity characterized by adding 5 atomic%, 0.05 to 0.5 atomic% of chromium and niobium in an aqueous solution in the range of 1 × 10 ^{−3 to} 5 × 10 ⁻² atomic% and firing. Resistor. 4. The voltage non-linear resistor according to claim 3, wherein niobium is niobium oxalate [Nb (HC ₂ O ₄ ) ₅ ].
A non-linear voltage resistor characterized by being added as an aqueous solution of: 5. A zinc oxide as a main component, and at least one rare earth element as a subcomponent in a total amount of 0.08-5.
0 at%, 0.1 to 10.0 at% of cobalt, at least one of magnesium and calcium in a total amount of 0.1 at.
0.01 to 5.0 atomic%, at least one of potassium, cesium and rubidium in a total amount of 0.01 to 1.0 atomic%, chromium of 0.01 to 1.0 atomic%, and boron of 5 × 1
0 ^-4 to 1 × 10 ^-1 atomic%, at least one of aluminum, gallium and indium in a total amount of 1 × 10 ^{-4 to} 5
× 10 ⁻² atomic% and antimony in an aqueous solution at 1 × 10 ⁻³
A non-linear voltage resistor characterized by being added and fired in the range of 5 × 10 ^-2 atomic%. 6. The voltage nonlinear resistor according to claim 5, wherein antimony is potassium antimonyl tartrate hemihydrate [C ₂ H ₂ (OH) ₂ (COOK) CO ₂ .SbO.
[ _1/2 ] H2O], which is added as an aqueous solution. 7. Zinc oxide as a main component, and as sub-components, praseodymium of 0.08 to 5.0 at%, cobalt of 0.1 to 10.0 at%, and potassium of 0.05 to 0.0 at%.
A voltage non-linearity characterized by being obtained by adding 5 at%, chromium at 0.05 to 0.5 at%, and antimony in an aqueous solution in the range of 1 × 10 ^{−3 to} 5 × 10 ^{−2 at} % and firing. Resistor. 8. The nonlinear resistor according to claim 7, wherein antimony is potassium antimonyl tartrate hemihydrate [C ₂ H ₂ (OH) ₂ (COOK) CO ₂ .SbO.
[ _1/2 ] H2O], which is added as an aqueous solution. 9. A composition comprising zinc oxide as a main component and at least one rare earth element as a subcomponent in a total amount of 0.08 to 5.0.
0 at%, 0.1 to 10.0 at% of cobalt, at least one of magnesium and calcium in a total amount of 0.1 at.
0.01 to 5.0 atomic%, at least one of potassium, cesium and rubidium in a total amount of 0.01 to 1.0 atomic%, chromium of 0.01 to 1.0 atomic%, and boron of 5 × 1
0 ^-4 to 1 × 10 ^-1 atomic%, at least one of aluminum, gallium and indium in a total amount of 1 × 10 ^{-4 to} 5
1 × 10 ^-2 atomic% and tungsten in aqueous solution
A voltage non-linear resistor characterized by being added in the range of ^{-3 to} 5 × 10 ^-2 atomic% and fired. 10. The nonlinear resistor according to claim 9, wherein the tungsten is potassium tungstate [K ₂ WO.
₄ ) A voltage non-linear resistor, which is added as an aqueous solution. 11. Zinc oxide as a main component, and as sub-components, praseodymium of 0.08 to 5.0 atomic%, cobalt of 0.1 to 10.0 atomic%, potassium of 0.05 to 0.05 atomic%.
A voltage characterized by adding 0.5 at%, chromium at 0.05 to 0.5 at%, and tungsten as an aqueous solution in the range of 1 × 10 ^{−3 to} 5 × 10 ^{−2 at} % and firing. Non-linear resistor. 12. The voltage non-linear resistor according to claim 11, wherein the tungsten is potassium tungstate [K ₂ W].
O ₄ ] as an aqueous solution.