JP2002226262A - Zinc oxide ceramic composition and its manufacturing method, and zinc oxide varistor and zinc oxide varistor and zinc oxide varistor device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a zinc oxide ceramic composition and its manufacturing method capable of producing a zinc oxide varistor stable for heat treatment with good electric property, and high reliability to an AC/DC load and a surge load at a low temperature of <=1100 deg.C. SOLUTION: The zinc oxide ceramic composition is obtained by adding 0.3-5.0 pts.wt. iron group oxides of 2 or 3 kinds selected from cobalt oxide, manganese oxide, and nickel oxide, 1.2-7.0 pts.wt. bismuth oxide, 0.1-3.0 pts.wt. antimony oxide, a boron oxide compound containing 0.03-0.5 pts.wt. boron oxide component, a chromium oxide compound containing 0.05-1.0 pts.wt. chromium oxide component and an aluminum compound containing 0.0001-0.05 pts.wt. aluminum component in terms of aluminum oxide, to 81.38 pts.wt. zinc oxide, and mixing, forming, and firing. Thereafter, a disk type varister is obtained by providing a pair of electrodes on both the faces of the ceramic composition, and a pair of lead wires on the electrodes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit in an electric circuit.
TECHNICAL FIELD The present invention relates to a zinc oxide varistor porcelain composition used for absorption and the like, a method for producing the same, a zinc oxide varistor, and a zinc oxide varistor apparatus using the same.

[0002]

2. Description of the Related Art A zinc oxide varistor is a zinc oxide raw material mixed powder containing zinc oxide, basic additives such as bismuth oxide, cobalt oxide and manganese oxide, and various oxides added for further improving the performance. It is manufactured using a zinc oxide porcelain composition obtained by molding and firing. It is known that the rise voltage of a zinc oxide varistor rises almost in proportion to the number of zinc oxide grain boundaries in a zinc oxide sintered body existing between electrodes. That is, the rise voltage rises by 3 to 4 volts per grain boundary in the sintered body. Therefore, 200-400V per 1mm thickness
In order to manufacture a zinc oxide varistor for a high voltage, it is necessary to manufacture a zinc oxide sintered body having ZnO particles having a small average particle diameter of about 7 to 15 μm. Therefore, conventionally, in order to manufacture a zinc oxide varistor for high voltage, a method of suppressing the growth of ZnO particles by adding a grain growth inhibitor of ZnO particles such as Sb ₂ O ₃ has been used. Sb ₂ O ₃ is an indispensable additive because it also plays an important role in stabilizing the nonlinear resistance characteristics of the zinc oxide varistor.

The rising voltage refers to a voltage between both terminals when a current of 1 mA flows through the varistor, and is represented by V1 mA. The voltage between both terminals when a current of 1 mA is applied to a sample having a thickness of 1 mm is defined as one of the constants of this material.
Expressed in V1mA / mm. This is the rise voltage per 1 mm thickness of the sample.

[0004]

However, conventionally, a high sintering temperature of 1150 ° C. to 1300 ° C. was required to obtain a high-performance, high-performance zinc oxide varistor for a high voltage. If fired at these high temperatures, even in air
The evaporation of Bi ₂ O ₃ etc. is active. In addition, Bi ₂ O ₃ easily reacts with many kinds of substances and easily corrodes many substances such as ceramic materials of furnace materials and containers. That is, the high sintering temperature not only caused power consumption, but also caused severe scattering of Bi ₂ O _{3 and the} like, and concomitant consumption of furnace materials and containers. Therefore,
There was a demand for a lower firing temperature. Also, when the firing temperature is high, depending on the place where the fired material is placed in the furnace, a difference occurs in the temperature, the heating rate, the vapor pressure of Bi ₂ O ₃ and Sb ₂ O _{3 and} the like,
It was difficult to keep these uniform, and there was a problem that the characteristics tended to vary.

[0005] On the other hand, if the firing temperature is lowered with the conventional composition of zinc oxide varistor, sufficient sintering is not performed, and therefore, the rising voltage rapidly increases, and ZnO
The non-linear resistance characteristics are reduced due to the variation in the particle size. In addition, there was a problem that deterioration due to power load, pulse current load, etc. was easy to progress.

When a powder mixture obtained by adding Sb ₂ O ₃ or the like to zinc oxide powder is subjected to pressure molding and sintering, Sb ₂
O ₃ easily sublimates to cover the surface of ZnO particles, and furthermore Sb ₂ O ₃
Reacts with ZnO to block the contact between ZnO and ZnO, thereby suppressing the growth of ZnO grains.

The ZnO—Bi ₂ O ₃ system, which is the basic composition of the porcelain of the zinc oxide varistor, has a eutectic composition having a eutectic temperature of 740 ° C., so that the mixture of ZnO and Bi ₂ O ₃ is 800 ℃
It reacts and sinters easily even at near temperatures. However hinder contact of two parties Sb ₂ O ₃ is gone over about the ZnO was sublimed at a low temperature ZnO and Bi ₂ O ₃ in the case where there is Sb ₂ O ₃ in the additives, these two Hinder the reaction between the two, making sintering difficult. Furthermore, ZnO, Bi ₂ O ₃ and Sb ₂ O ₃ react to form a strong pyrochlore phase film of ZnO—Bi ₂ O ₃ —Sb ₂ O ₃ between ZnO and ZnO, which further promotes sintering. Make it go. ZnO-Bi ₂ O ₃ -Sb ₂ O ₃
In the system, a solid pyrochlore phase is easily formed at low temperature,
The formation of the liquid phase Bi ₂ O ₃ phase is hindered and the progress of liquid phase sintering is delayed. As described above, Sb ₂ O ₃ forms a film on ZnO to form ZnO
It blocks the contact between particles, then turns into a Sb ₂ O ₃ -ZnO film, then absorbs Bi ₂ O ₃ to form a chemically stable pyrochlore film, preventing the contact between ZnO particles.

In the case of a zinc oxide varistor, an iron group oxide is added.
Get it, ZnO-Bi _TwoO_Three-Sb_TwoO_Three+ (CoO, MnO, NiO)
However, the pyrochlore phase still reacts with ZnO and Bi_TwoO_Three
A high temperature of 1200 ° C or higher is required to form the liquid phase of the main component
did. Moreover, in this system, Bi_TwoO_ThreeThe liquid phase of the main component is shaped
Even if it is formed, the reverse reaction occurs in the cooling process, and at room temperature ZnO particles
A pyrochlore phase has formed in the world. Bi at grain boundaries_TwoO_ThreePhase formed
Excellent properties when pyrochlore phase is present instead
No barista with a slab was obtained.

ZnO—Bi ₂ O ₃ —S in which Cr ₂ O ₃ is added to the above composition
In the b ₂ O ₃ + (CoO, MnO, NiO) + Cr ₂ O ₃ system, the pyrochlore phase reacts with ZnO to form a Bi ₂ O ₃ main component liquid phase.
Although a high temperature of 00 ° C or higher was required, once formed Bi
The liquid phase of ₂ O ₃ main component was stably present at the grain boundaries even after cooling, and did not return to the pyrochlore phase. And it exhibited excellent initial characteristics as a varistor.

In order to suppress the sublimation of Sb ₂ O ₃ , B
The mixture of i ₂ O ₃ + Sb ₂ O ₃ is subjected to a heat treatment and ZnO is treated with Bi ₂ O ₃
It has been found that adding + Sb ₂ O ₃ is effective. When this method is employed, sublimation of Sb ₂ O ₃ is suppressed even at 900 ° C., formation of a film such as a pyrochlore phase on the surface of ZnO particles is suppressed, and sintering proceeds considerably. However, a ZnO varistor with stable electric characteristics could not be obtained.

The excellent electrical characteristics of a zinc oxide varistor means that a high current generated instantaneously in a circuit due to, for example, a small leakage current and a high non-linear resistance index of 0.1 mAα1 mA described later is absorbed. To prevent a high voltage from being generated in the circuit. In addition, the term “excellent in reliability” means that electrical characteristics are deteriorated even when a voltage is applied for a long time, when a power load is applied at a high temperature for a long time, or when a pulse current is applied. And the fact that the original electrical characteristics are maintained. However, the conventional zinc oxide varistor has inherent instability as described below.

Normal zinc oxide has interstitial zinc atoms, so-called interstitial Zn, between lattice points where zinc and oxygen atoms of zinc oxide crystals are located.
The conductivity of zinc oxide is due to electrons excited from these interstitial Zn atoms. One of the biggest problems with conventional zinc oxide varistors is electrical instability. One of the electrical instabilities is that when a DC or AC voltage is continuously applied to the element for a long time, the VI characteristics deteriorate and the current gradually increases, and the other is that a zinc oxide varistor If the sintered body is subjected to a heat treatment at around 700 ° C, the VI characteristics will be rapidly deteriorated. In the latter case, the leakage current increases, and in some cases, it may not be practical. These two VIs
The deterioration of the characteristics is caused by the movement of the interstitial Zn in the depletion layer generated along the grain boundary of the zinc oxide particles of the sintered body of the zinc oxide varistor. When aluminum is not added, in the case of a zinc oxide varistor prepared by a conventional manufacturing method, 2 to 7
It is said that there are conduction electrons supplied from interstitial Zn atoms of about × 1017 / cm ^3. The number of conduction electrons in ZnO particles in zinc oxide varistor is M
ukae, Tsuda and Nagasawa ("Capacitance-vs-Voltage Characteristics of Z
nO Varistors ", J. Appl. Phys., 50 [6] 4475-
76 (1977)).

It is said that the concentration of interstitial Zn atoms in ZnO decreases as the oxygen partial pressure in the atmosphere increases, and increases as the atmosphere temperature increases. Bi ₂ to such a ZnO powder
When O ₃ , Co ₃ O ₄ , Cr ₂ O ₃ , MnO ₂ , NiO, Sb ₂ O ₃ etc. are added, pressed and sintered in a high temperature atmosphere, ZnO with extremely high nonlinear resistance characteristics A varistor was obtained. At the grain boundaries of these sintered bodies, conduction electrons in the n-type semiconductor ZnO on both sides of the grain boundaries are captured by the grain boundaries, so that a depletion layer is formed on both sides of the grain boundaries, and electrons are formed on both sides of the grain boundaries. A barrier is formed to prevent the transfer. A so-called double Schottky barrier is formed. Since the main conductor of n-type ZnO semiconductor is conduction electrons generated from interstitial Zn atoms, interstitial Zn atoms with positive charge remain in the depletion layer .

Even when no voltage is applied to the sintered body from the outside, a strong electric field works in the depletion layer.
The positively charged interstitial Zn atoms in the depletion layer are attracted to grain boundaries. When a voltage is applied to such a sintered body from the outside, the voltage is applied only to the thin depletion layer, so that a larger electric field acts in one of the depletion layers, and the interstitial Zn atom Is relatively mobile, so part of it moves toward the grain boundary and reaches the grain boundary. Then, the positively charged interstitial Zn atom combines with the negatively charged oxygen atom to form neutral ZnO. At the same time, the negative charge trapped in the grain boundaries decreases, so the barrier that had provided the varistor characteristics is lowered and the nonlinear resistance characteristics are reduced. As described above, even when a voltage is not externally applied to the sintered body, a strong electric field is working in the depletion layer, and the positively charged interstitial Zn atoms in the depletion layer are It is attracted to grain boundaries. In such a situation, when the element is heated, the interstitial Zn atoms are likely to move due to the heat, and some move toward the grain boundaries due to the electric field, and have a negative charge at the grain boundaries. Bonds with oxygen atoms to form neutral ZnO, which reduces the nonlinear resistance characteristics of varistors. As described above, the semiconductorization of ZnO crystal was mainly caused by interstitial Zn atoms naturally occurring in the manufacturing process, and was therefore accompanied by electrical instability.

On the other hand, the conversion of ZnO crystal into an n-type semiconductor is as follows.
It was also performed by adding Al ₂ O ₃ . In particular, in order to improve the current-voltage non-linear resistance characteristics in a high current region, it is important to increase the electric conductivity in the zinc oxide particles, but the electric conductivity brought about by naturally occurring interstitial Zn atoms alone is not sufficient. Not enough. Therefore, Al ₂ O ₃ is added as a donor to improve the current-voltage nonlinear resistance characteristics especially in the high current region, and the improvement of the current-voltage nonlinear resistance characteristics in the high current region increases the electric conduction in the ZnO particles. This was achieved. However, even when Al ₂ O ₃ is added, if there is an interstitial Zn atom with a positive charge in the depletion layer, the instability problem is the same as when Al ₂ O ₃ is not added, When applying a voltage or performing heat treatment, the barrier is reduced, and the non-linear resistance characteristic is reduced and the current is increased. In particular, when heat treatment was performed for electrode baking or side coating, there was a problem that the non-linear resistance characteristics in the low current region were greatly reduced.

The sintered body of the ZnO varistor is pre-
Heat treatment increases the stability to AC application, so this method has been adopted as a countermeasure against deterioration, but it cannot be said that the instability has been sufficiently eliminated.
Heat treatment at ~ 600 ° C reduces interstitial Zn ions in the depletion layer, which caused degradation.
As a result, the instability of the IV characteristics is reduced, but the problem has not been solved.

The cause of the instability of the electrical characteristics is the movement of the interstitial Zn.
Al is added to the lattice point where Zn atoms come as a donor to reduce Zn.
It was necessary to replace the atoms so that the electrical conduction in the zinc oxide particles was covered by electrons from the Al donor. It is considered necessary to maintain zinc oxide at a high temperature under a high oxygen partial pressure as a method of reducing interstitial Zn. As one of the methods, sintering a zinc oxide varistor under a high oxygen pressure is considered, but it is not realistic. Thus, for many years, zinc oxide porcelain compositions for varistor elements and varistor devices have had two problems: lowering the sintering temperature and stabilizing the electrical characteristics.

The present invention solves the above problems and provides a zinc oxide porcelain composition for producing a zinc oxide varistor excellent in electrical characteristics such as non-linear resistance characteristics and reliability at low temperature sintering with high yield. And a method of manufacturing the same, and a zinc oxide varistor excellent in electrical characteristics and reliability.

[0019]

In order to achieve the above object, that is, to provide an element having high performance and excellent stability at low cost, the zinc oxide porcelain composition of the present invention comprises zinc oxide (ZnO). 81.38 parts by weight of at least cobalt oxide (CoO, or Co ₂ O ₃ , or Co ₃ O ₄ ) and manganese oxide (MnO,
Or MnO ₂ , or Mn ₂ O ₃ , or Mn ₃ O ₄ ) and nickel or nickel oxide (NiO).
5.0 parts by weight bismuth oxide (Bi ₂ O ₃₎ and 1.2 to 7.0 parts by weight of antimony oxide (antimony trioxide Sb ₂ O ₃ or tetroxide antimony Sb ₂ O ₄ or diantimony pentaoxide Sb ₂ O ₅₎ To
0.1 to 3.0 parts by weight boron oxide component (B ₂ O ₃₎ 0.03~0.5 containing parts boron oxide-containing compound and chromium oxide component (Cr ₂ O ₃₎ 0.05~1.0 containing parts chromium oxide-containing synthetic 0.0001- in terms of aluminum oxide (Al ₂ O ₃ )
An aluminum compound containing 0.05 parts by weight of an aluminum component is added, mixed, molded, and fired.

Further, in order to achieve the above object, the zinc oxide porcelain composition of the present invention comprises at least two or three kinds selected from cobalt oxide, manganese oxide and nickel oxide added to the above zinc oxide porcelain composition. The iron group oxide is an iron group oxide composed of an iron group having at least one of these iron group oxides having a valence greater than divalent, and a preferable addition amount is 0.1 to 2.0 parts by weight of cobalt oxide.
Manganese oxide is 0.1-1.5 parts by weight, nickel oxide is 0.1-
It has a configuration of 1.5 parts by weight.

In order to achieve the above object, the zinc oxide porcelain composition of the present invention is characterized in that, in the above zinc oxide porcelain composition, 1.2 to 7.0 parts by weight of bismuth oxide is added, and the total bismuth component to be added is Bi ₂ O _3. 1.2 to 7.0 parts by weight in terms of.

In order to achieve the above object, the zinc oxide porcelain composition according to the present invention is characterized in that 0.1 to 3.0 parts by weight of antimony oxide is added to the zinc oxide porcelain composition, and the total antimony component to be added is Sb ₂ O _3. 0.1 to 3.0 parts by weight.

In order to achieve the above object, the zinc oxide porcelain composition of the present invention is preferably fired at a temperature of 800 ° C. to 1100 ° C., more preferably at a temperature of 850 ° C. to 1000 ° C. It has a configuration.

In order to achieve the above object, according to the zinc oxide porcelain composition of the present invention, in the above zinc oxide porcelain composition, firing is performed while forming closed pores containing high-pressure oxygen therein. It has a configuration of firing.

In order to achieve the above object, the zinc oxide porcelain composition of the present invention has a structure in which closed pores containing high-pressure oxygen are contained therein.

In order to achieve the above object, the zinc oxide porcelain composition of the present invention is characterized in that zinc oxide contains at least two or three iron group oxides selected from cobalt oxide, manganese oxide and nickel oxide, and bismuth oxide. Antimony oxide (antimony trioxide or diantimony tetroxide or diantimony pentoxide), a compound containing boron oxide, a compound containing chromium oxide and an aluminum compound are added and mixed,
In a zinc oxide porcelain composition obtained by molding and firing, the boron oxide-containing composition is an oxide of 1 to 4 selected from at least chromium oxide, bismuth oxide, antimony oxide and rare earth oxide in addition to boron oxide. It has a structure that it is a compound containing a substance.

In order to achieve the above object, the zinc oxide porcelain composition of the present invention further comprises a zinc oxide containing at least two or three iron group oxides selected from cobalt oxide, manganese oxide and nickel oxide, and bismuth oxide. Antimony oxide (diantimony trioxide or diantimony tetroxide or diantimony pentoxide), a compound containing boron oxide, a compound containing chromium oxide, and an aluminum compound are added and mixed,
In a zinc oxide porcelain composition obtained by molding and firing, the chromium oxide-containing composition is an oxide of 1 to 4 selected from at least boron oxide, bismuth oxide, antimony oxide and rare earth oxide in addition to chromium oxide. It has a structure that it is a compound containing a substance.

Further, in order to achieve the above object,
The zinc oxide porcelain composition of the present invention comprises zinc oxide, at least two or three iron group oxides selected from cobalt oxide, manganese oxide and nickel oxide, bismuth oxide and antimony oxide (antimony trioxide or dioxide tetroxide). Antimony or diantimony pentoxide), a composition containing boron oxide, a composition containing chromium oxide, and an aluminum compound are added, mixed, molded, and fired. The chromium oxide-containing composition is a composition having a composition that is a boron oxide / chromium oxide-containing composition.

Further, in order to achieve the above object, the zinc oxide porcelain composition of the present invention comprises: Add bismuth, antimony oxide (diantimony trioxide or diantimony pentoxide or diantimony pentoxide), a composition containing boron oxide, a composition containing chromium oxide, and an aluminum compound, mix, mold, fire, and cool. After that, 500 ℃ ~ 800 again
As a result of the above heat treatment, the zinc oxide porcelain composition contains a γ-bismuth phase as a bismuth oxide main component phase.

Further, in order to achieve the above object,
The zinc oxide porcelain composition of the present invention has a configuration in which a part of zinc oxide as a main component is replaced with magnesium oxide.

Further, in order to achieve the above object,
The zinc oxide porcelain composition of the invention has a zinc oxide (ZnO)
Parts (1 mole) at least cobalt oxide (CoO or Co_TwoO
_ThreeOr Co_ThreeO_Four) And manganese oxide (MnO or MnO)_Two, Or
Mn_TwoO_ThreeOr Mn_ThreeO_Four) And nickel oxide (NiO)
Oxidized 0.3 to 5.0 parts by weight of two or three iron group oxides
Bismuth (Bi_TwoO_Three) 1.2 to 7.0 parts by weight of antimony oxide
(Diantimony trioxide Sb_TwoO_ThreeOr diantimony tetroxide Sb_Two
O_FourOr diantimony pentoxide Sb _TwoO_Five) With 0.1 to 2.0 parts by weight
Boron oxide (B_TwoO_Three) Acid containing 0.03-0.5 parts by weight of component
Boron iodide-containing compounds and chromium oxide (Cr_TwoO_Three) Ingredient 0.05 ~
Chromium oxide-containing composition containing 1.0 parts by weight and aluminum oxide
Minium (Al_TwoO_ThreeA) of 0.0001-0.05 parts by weight
An aluminum compound containing a luminium component;
, Germanium oxide (GeOr), niobium oxide (Nb
_TwoO_Five), Lead oxide (PbO), Silicon oxide (SiOr), Tin oxide
(SnO_Two), Tantalum oxide (Ta_TwoO_Five), Titanium oxide (Ti
O_Two), Tungsten oxide (WO_Three), And rare earth oxides
With more selected oxides, alone or with other oxides
Both have the composition of forming a compound and adding it
It is.

In order to achieve the above-mentioned object, that is, to provide an element having high performance and excellent stability at low cost,
The zinc oxide porcelain composition of the present invention is more preferably made of zinc oxide (ZnO) 81.38 in order to suppress variations in electrical characteristics.
By weight, at least cobalt oxide (CoO, or Co ₂ O ₃ , or Co ₃ O ₄ ) and manganese oxide (MnO, or MnO ₂ , or Mn ₂ O ₃ ,
Alternatively, 0.5 to 4.0 parts by weight of two or three iron group oxides selected from Mn ₃ O ₄ ) and nickel oxide (NiO), 1.2 to 6.0 parts by weight of bismuth oxide (Bi ₂ O ₃ ) and antimony oxide ( oxide containing diantimony trioxide SbrO ₃ or tetroxide antimony Sb ₂ O ₄ or diantimony pentaoxide Sb ₂ O ₅₎ 0.1 to 2.0 parts by weight boron oxide component (B ₂ O ₃₎ 0.05~0.45 parts by weight A chromium oxide-containing composition containing 0.08 to 0.8 parts by weight of a boron-containing composition and a chromium oxide component (Cr ₂ O ₃ ) and an aluminum component of 0.0003 to 0.02 parts by weight converted to aluminum oxide (Al ₂ O ₃ ) And the aluminum compound to be added, mixed, molded, and fired.

Next, in order to achieve the above object, a method for producing a zinc oxide porcelain composition according to the present invention comprises a step of preparing a boron oxide-containing composition, a step of preparing a chromium oxide-containing composition, The powder contains at least two or three iron group oxides selected from cobalt oxide, manganese oxide and nickel oxide, bismuth oxide, antimony oxide (diantimony trioxide or diantimony pentoxide or diantimony pentoxide) and the oxidation A step of adding and mixing the boron-containing compound, the chromium oxide-containing compound, and the aluminum compound to form a zinc oxide mixed powder, and a step of forming the zinc oxide mixed powder to form a molded body, And a step of firing the molded body.

In order to achieve the above object, a method for producing a zinc oxide porcelain composition according to the present invention is characterized in that, in the above method for producing a zinc oxide porcelain composition, the step of producing a boron oxide-containing composite comprises In addition, a heat treatment is performed on a boron oxide-containing mixture containing at least one oxide selected from chromium oxide, bismuth oxide, antimony oxide, and rare earth oxide, preferably from 300 ° C. to a temperature equal to or higher than the melting temperature. The process is a process of producing a boron oxide-containing composite by performing a heat treatment at such a temperature.

In order to achieve the above object, a method for producing a zinc oxide porcelain composition according to the present invention is characterized in that, in the above-mentioned method for producing a zinc oxide porcelain composition, the step of producing a chromium oxide-containing composite comprises: In addition to the above, heat treatment is performed on a chromium oxide-containing mixture containing at least one oxide selected from boron oxide, bismuth oxide, antimony oxide, and rare earth oxide, preferably from 300 ° C. to a temperature equal to or higher than the melting temperature. The process is a process of producing a chromium oxide-containing composite by performing a heat treatment at any temperature.

In order to achieve the above object, a method for producing a zinc oxide porcelain composition of the present invention comprises a step of preparing a boron oxide-containing composition, a step of preparing a chromium oxide-containing composition, and At least two or three iron group oxides selected from cobalt oxide, manganese oxide and nickel oxide, bismuth oxide, antimony oxide (diantimony trioxide or diantimony pentoxide or diantimony pentoxide), and the above-mentioned boron oxide-containing synthesis Adding and mixing the product, the chromium oxide-containing compound, and the aluminum compound to form a zinc oxide mixed powder, forming the zinc oxide mixed powder to form a compact, and firing the compact. In the above-described production method, the step of preparing a boron oxide-containing composition and the step of preparing a chromium oxide-containing composition include the steps of: Subjecting the mixture containing boron oxide and chromium oxide to a heat treatment to produce a composite containing boron oxide and chromium oxide.

In order to achieve the above object, a method for producing a zinc oxide porcelain composition according to the present invention comprises subjecting the above-mentioned mixture containing boron oxide and chromium oxide to a heat treatment to produce a boron oxide / chromium oxide-containing composite. The present invention has a configuration in which the step is a step of preparing a composite containing boron oxide and chromium oxide by performing a heat treatment at any temperature from 300 ° C. to a temperature equal to or higher than the melting temperature. When homogeneity is required in a small amount of production, pulverization is difficult, but it is preferable to melt at a high temperature, quench and pulverize. However, when mass production is desired, 300 ° C to 450 ° C can be mentioned, and more preferably 350 ° C to 400 ° C.

Further, in order to achieve the above object, the method for producing a zinc oxide porcelain composition of the present invention has a configuration in which the step of firing the molded body is a step of firing the molded body at 800 ° C. to 1100 ° C. It is something.

In order to achieve the above object, a method for producing a zinc oxide porcelain composition according to the present invention comprises a step of preparing a boron oxide-containing composition, a step of preparing a chromium oxide-containing composition, At least two or three iron group oxides selected from cobalt oxide, manganese oxide and nickel oxide, bismuth oxide, antimony oxide (diantimony trioxide or diantimony pentoxide or diantimony pentoxide), and the above-mentioned boron oxide-containing synthesis Adding and mixing the product and the chromium oxide-containing compound and the aluminum compound to form a zinc oxide mixed powder, forming the zinc oxide mixed powder to form a molded body, Baking to produce a fired product, 500 to 800 ° C.
And a step of performing a heat treatment.

In order to achieve the above object, a zinc oxide varistor according to the present invention provides a zinc oxide varistor comprising at least two or three iron group oxides selected from cobalt oxide, manganese oxide and nickel oxide, bismuth oxide and Antimony (diantimony trioxide or diantimony tetroxide or diantimony pentoxide), a compound containing boron oxide, a compound containing chromium oxide and an aluminum compound are added and mixed,
It has a configuration in which an electrode is formed by forming, firing, and forming.

In order to achieve the above object, a zinc oxide varistor according to the present invention provides a zinc oxide varistor comprising at least two or three iron group oxides selected from cobalt oxide, manganese oxide and nickel oxide, bismuth oxide and Antimony (diantimony trioxide or diantimony pentoxide or diantimony pentoxide), a composition containing boron oxide, a composition containing chromium oxide, and an aluminum compound are added and mixed,
It has a configuration in which electrodes are formed on a zinc oxide porcelain composition that has been formed, fired, cooled, and then subjected to a heat treatment at 500 ° C. to 800 ° C. again.

In order to achieve the above object, a zinc oxide varistor according to the present invention provides a zinc oxide varistor comprising at least two or three iron group oxides selected from cobalt oxide, manganese oxide and nickel oxide, bismuth oxide and An antimony, a boron oxide-containing compound, a chromium oxide-containing compound, and an aluminum compound are added and mixed to prepare a zinc oxide mixed powder, and a compact is formed by applying pressure to the zinc oxide mixed powder. An inorganic insulating film forming material is applied to the side surface of the molded body, and is baked, and at the same time, a side surface high-resistance layer is formed to form an electrode.

In order to achieve the above object, a zinc oxide varistor according to the present invention provides a zinc oxide varistor comprising at least two or three iron group oxides selected from cobalt oxide, manganese oxide and nickel oxide, bismuth oxide and oxide An antimony, a boron oxide-containing compound, a chromium oxide-containing compound, and an aluminum compound are added and mixed to prepare a zinc oxide mixed powder, and a compact is formed by applying pressure to the zinc oxide mixed powder. An electrode material is applied to two surfaces of the molded body, and the electrode is formed simultaneously with firing.

Further, in order to achieve the above object, a zinc oxide varistor of the present invention is a laminated zinc oxide varistor, wherein zinc oxide is at least two or three kinds selected from cobalt oxide, manganese oxide and nickel oxide. An iron group oxide, bismuth oxide, antimony oxide, a compound containing boron oxide, a compound containing chromium oxide, and an aluminum compound are added and mixed, and formed into a thin plate. It is provided with a configuration of alternately stacking and firing.

In order to achieve the above object, the zinc oxide varistor device of the present invention is characterized in that zinc oxide contains at least two or three iron group oxides selected from cobalt oxide, manganese oxide and nickel oxide, and bismuth oxide. Antimony oxide (diantimony trioxide or diantimony pentoxide or diantimony pentoxide), a compound containing boron oxide, a compound containing chromium oxide, and an aluminum compound are added, mixed, molded, fired, and oxidized. Obtaining a zinc porcelain composition, covering the side surfaces of the zinc oxide porcelain composition with an insulating coating, forming electrodes on two sides of the zinc oxide porcelain composition to obtain a single zinc oxide varistor, It has a configuration in which a zinc varistor or a plurality of zinc oxide varistors are obtained by being enclosed in an insulating container.

[0046]

BEST MODE FOR CARRYING OUT THE INVENTION The zinc oxide porcelain composition of the present invention comprises:
Various additives are added to the main component ZnO powder to adjust the sintering and improve the electrical characteristics of the sintered body after sintering, and some of them are mixed and heat-treated. It is obtained by adding, mixing, pressing the mixture under pressure, and firing the molded body. The present invention comprises a zinc oxide porcelain composition thus obtained, a method for producing the same, a zinc oxide varistor obtained by applying an electrode to the zinc oxide porcelain composition, and a zinc oxide varistor device using the same.

The zinc oxide porcelain composition of the present invention is sintered in the presence of closed pores having a high oxygen partial pressure, generating oxygen in a closed sintered body to prevent the formation of interstitial Zn. That is, in addition to zinc oxide, bismuth oxide, antimony oxide, iron group oxides such as cobalt, manganese and nickel, and aluminum compounds,
Bi ₂ O ₃ principal components of the liquid phase is added and reacted with the pre-Cr ₂ O ₃ and other additives to the Cr ₂ O ₃ to exist stably applied efficiently liquid phase, good wettability liquid phase A boron-containing substance was added to form a mixture, and the mixture was then mixed, pressed, and sintered. The zinc oxide porcelain composition fired in this way had only excellent initial characteristics. Not even A
Excellent stability even for C, DC, pulse application and heat treatment at 500 ° C to 800 ° C.

In the zinc oxide porcelain composition of the present invention, in order to secure the priority of the reaction in the firing process, a part of the additives are mixed and heat-treated in advance, and added to the zinc oxide together with other additives. It is molded and fired. In addition, in the zinc oxide porcelain composition of the present invention, aluminum is the sole donor for preventing the formation of interstitial Zn, which causes deterioration of electrical characteristics, and for converting zinc oxide into an n-type semiconductor. In the firing of zinc oxide porcelain, the chromium oxide added to prevent the formation of a pyrochlore phase at low temperatures and to promote the formation of a liquid phase containing bismuth oxide as a main component at low temperatures reacts with zinc oxide first and reacts with ZnCr. _In order to prevent the formation of ₂ O ₄ , heat treatment is performed in advance with boron oxide, bismuth oxide, antimony oxide, or the like to form a chromium oxide-containing composite, and then added. In the present invention, in order to prevent the formation of interstitial Zn, it is necessary to form an oxygen-excess atmosphere inside the sintered body during sintering, but this generates oxygen by decomposition and solid solution in zinc oxide. This is made possible by the addition of an iron group oxide. Then, the generated oxygen is confined inside the sintered body by forming a liquid phase at the grain boundary. Finally, a ZnO-Sb ₂ O ₅ spinel is formed. In these devices, it is necessary to uniformly dope tail zinc into zinc oxide particles in order to reduce interstitial Zn and instead maintain conduction electrons. By efficiently generating closed pores having a high oxygen partial pressure and sintering as if sintering under high-pressure oxygen, an element having high performance and excellent stability could be obtained.

The zinc oxide porcelain composition contains 950
Since these materials include those having excellent electrical properties by sintering at a temperature of ≦ ° C. or less, these zinc oxide porcelain compositions are formed into sheets, alternately laminated with electrode materials, and sintered. When the electrodes are connected by a predetermined connection method, a laminated varistor is obtained. In a conventional laminated varistor, a firing temperature of 1200 ° C. or more was required to obtain good characteristics. To that end, a noble metal such as platinum was used as an electrode material. However, when a zinc oxide porcelain composition that can be sintered at a temperature of 950 ° C. or less is used, it is possible to use relatively inexpensive silver as an electrode material. Thus, one of the advantages of the present invention is that silver can be integrally fired as the internal electrode of the varistor.

[0050]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Examples. In the following examples, “weight” is
May be displayed as "wt". Although not shown in the following examples, the aluminum addition amount and the iron group oxide addition amount

Example 1 B ₂ O ₃ powder and Cr ₂ O _{3 in} molar ratio
Was mixed so as to be 1: 1. After subjecting these mixed powders to heat treatment at 500 ° C for 5 hours under air atmosphere,
Monomaron pot ball made of stabilized zirconia
B consisting of B ₂ O ₃ and Cr ₂ O ₃ by tail milling
₂ O ₃ / Cr ₂ O ₃ synthetic powder was obtained. ZnO powder and B ₂ O ₃ / C
weight and r ₂ O ₃ synthetic powder, and Biro ₃ powder, and Co ₃ O ₄ powder, and MnO ₂ powder, and NiO powders, and Sb ₂ O ₃ powder, and _{Al (NO 3) 3 · 9H} 2 O powder 81.38: 0.4: 3.4: 0.954: 0.414: 0.383:
x: It was blended so as to be 0.015 and mixed and pulverized by a ball mill of a monomalon pot by a wet method. However, x = 0.05, 0.1, 0.2, 0.5, 0.8, 1.0, 1.5, as the amount of Sb ₂ O 3
2.0 and 3.0 are selected. The obtained compounded powder was dried and pressed into a disk. Next, the temperature of the obtained molded body was raised in the air at a temperature rising rate of 50 ° C./hour, and the temperature was maintained at 900 ° C. for 10 hours. The sample size of the obtained sintered body was 1.2 mm in thickness and 14 mm in diameter. Further, the obtained sintered body was heated at 700 ° C.
For 1 hour.

Next, a method for producing a zinc oxide varistor will be described with reference to FIG. FIG. 1 is a schematic perspective view of a disk-type zinc oxide varistor 10 made using the zinc oxide porcelain composition of the present invention. An aluminum layer (not shown) is formed by spraying aluminum on both surfaces of the sintered body 11 obtained as described above, and then copper is sprayed on the aluminum layer formed on both surfaces. Thus, the electrode 12 was formed. After the lead wire 13 was attached to the electrode 12 by soldering, a porcelain other than the lead wire and the electrode portion were grease-coated to obtain a zinc oxide varistor.

The electrical characteristics of the zinc oxide varistor thus obtained were evaluated. The initial electrical characteristics include a rising voltage V1mA / mm (voltage for 1 mm thickness between both terminals when a current of 1 mA flows) and a non-linear resistance index of 0.1 mA
α1mA (value obtained using V1mA and V0.1mA) was measured (in the following description, the nonlinear resistance index is 0.1 mA
α1mA is sometimes simply referred to as α value). The larger the nonlinear resistance index, the greater the surge absorption capacity. or,
The reliability to DC load was evaluated. A DC load of 0.5 watts is applied for 500 hours in a high-temperature atmosphere of 80 ° C., cooled, and the rate of change of the varistor rise voltage V1mA1V1mA / V1mA
(DC load change rate) was measured. The smaller the rate of change ΔV1mA / V1mA of the varistor rise voltage V1mA, the more stable the electrical characteristics of the zinc oxide varistor, indicating higher reliability.

Further, the reliability of the surge was evaluated. Variation rate of varistor rise voltage V1mA by applying 8 × 20μsec, 2.5kA pulse 10 times１０V1mA / V1mA
(Surge change rate) was measured. Table 1 shows the composition of the sample, and Table 2 shows the evaluation results of the electrical characteristics. The smaller the value of the surge rate, the more stable the electrical characteristics of the zinc oxide varistor and the higher the reliability. In each case, the reliability is high when the absolute value of the change rate is 5% or less. The numerical values indicating the evaluation results of the electrical characteristics indicate the minimum value and the maximum value in the lot.

[0055]

[Table 1]

[0056]

[Table 2]

As shown in Tables 1 and 2, the zinc oxide varistor using the zinc oxide porcelain composition of the present embodiment sinters even at a low temperature of 900 ° C. except for the sample with x = 3.0 (sample number # 009). It has good non-linear resistance characteristics except for the sample of x = 0.05 (sample number # 001), and the rate of change of the rising voltage V1mA (for both long-time DC load and surge) ( The absolute value of (ΔV1mA / V1mA) was 5% or less, indicating excellent reliability. Further, as shown in Table 2, the variation in the electrical characteristics in the lot was small. Although not shown in Table 2, when the zinc oxide varistor was prepared using the zinc oxide porcelain of the present example, the variation in the electrical characteristics between lots was as small as the variation in the electrical characteristics in the lot. Although the sample # 001 had excellent initial non-linear resistance characteristics, the start-up voltage and the non-linear resistance characteristics varied, and the characteristic deterioration due to voltage load and heat treatment was slightly large. In the case of # 009, when the firing temperature was increased, the grain growth progressed and measurement became possible, but no good characteristics were shown.

(Example 2) B obtained in Example 1_TwoO_ThreePowder and
Cr_TwoO_ThreeB consisting of powder of_TwoO_Three/ Cr_TwoO_ThreeUsing synthetic powder, Zn
O, B_TwoO_Three/ Cr_TwoO_ThreeSynthetic powder, Bi_TwoO_Three, Co_ThreeO_Four, MnO_Two, Ni
O, Sb _TwoO_Three, Al (NO_Three)_Three・ 9H_TwoO, by weight ratio, 81.38: 0.4:
4.2: 0.954: 0.414: 0.383: 0.6: 0.015
The mixture is mixed by a wet method using a ball mill with a monomalon pot.
After crushing, use a spray dryer to mix zinc oxide
A powder was obtained using the zinc oxide mixed powder thus obtained.
Table 3 shows the composition of the sample.

[0059]

[Table 3]

The zinc oxide mixed powder obtained by the spray dryer is formed into a column by a RIP (Rubber Isostatic Press, rubber isostatic press) method, and bismuth borosilicate glass powder and MnO ₂ are formed on the side surface of the obtained formed body. Was baked at 900 ° C. and 950 ° C. for 10 hours each to obtain columnar zinc oxide porcelains # 101 and # 102. The size of the obtained zinc oxide porcelain was 32 mm in diameter and 28 mm in height. Electrodes were formed by spraying aluminum metal on the upper and lower surfaces of the zinc oxide porcelain, and mica-greasing coating was applied to the sides to obtain arrester-type zinc oxide varistors. V1mA was V1mA = 6.05kV and V1mA = 5.94, respectively.
kV. FIG. 2 shows an arrester type zinc oxide varistor device 2 prepared using the zinc oxide porcelain composition of the present invention.
0 is a sectional view. Element electrodes 22 are formed on both upper and lower surfaces of the zinc oxide porcelain 21 by aluminum spraying. Further, on the side surface of the zinc oxide porcelain, a side insulating film 23 of a mica-greasing film made of a mixture of mica and fat is formed, and the zinc oxide varistor element is formed by the zinc oxide porcelain, the device electrode, and the side insulating film. Has formed. At the lower part of the zinc oxide varistor element, a ground side terminal 2 having a mounting screw hole 24 is provided.
5, a line-side terminal 27 having a screw hole 24 for attachment via a spring 26, and both terminals and a zinc oxide varistor element are molded in a greasing tube 28. Table 4 shows the current-voltage characteristics of the arrester type zinc oxide varistor device.

[0061]

[Table 4]

As shown in Table 4, in the arrester type zinc oxide varistor device using the zinc oxide porcelain of the composition of this embodiment, both the # 101 and # 102 have excellent non-linear resistance characteristics even in a high current region. I understand. Next, an acceleration test of AC power application was performed to predict the service life. The service life is one of the most important evaluation items of the arrester. Here, the test was performed under the conditions of an ambient temperature of 130 ° C. and a charge rate of 95%.
As a result, the initial Ir of 1 mA hardly changed for the test for more than 100 hours for both devices.
Under the condition of 0%, a life of more than 100 years is guaranteed.

Example 3 B in molar ratio_TwoO_ThreePowder and Sb_TwoO_Three
2: 1 powder, Cr_TwoO_ThreePowder and Sb_TwoO_Three1: 1 powder
And mixed. These mixed powders are put under air atmosphere,
5 hours at 380 ° C and 5 hours at 600 ° C respectively
After treatment, a monomer that uses stabilized zirconia as a cobblestone
B by tail milling in a ball mill of a long pot_TwoO_Three
And Sb_TwoO_ThreeConsisting of B_TwoO_Three/ Sb_TwoO_ThreeSynthetic powder, Cr_TwoO_ThreeAnd Sb_TwoO_ThreeYo
Rin Cr_TwoO_Three/ Sb_TwoO_ThreeA synthetic powder was obtained. ZnO powder and the above
B_TwoO_Three / Sb_TwoO_Three Synthetic powder and Bi_TwoO_ThreePowder and the Cr_TwoO _Three/ S
b_TwoO_ThreePowder and Co_ThreeO_FourPowder and MnO_Two Powder, NiO powder, and S
b_TwoO_FourPowder and Al (OH) (CH_ThreeCOO)_TwoAnd the weight ratio of 81.38: x:
4.2: x: 0.954: 0.414: 0.383: 0.5: 0.0065
And pulverized by a wet method for 18 hours.
A zinc oxide sintered body was made in a similar way.
Then B_TwoO_Three/ Sb_TwoO_ThreeQuantity and Cr_TwoO_Three/ Sb_TwoO_ThreeX =
0.05, 0.1, 0.2, 0.3, 0.5, 1.0, 2.0, 3.0,
I chose 4.0. Silver electrode material on both sides of the porcelain thus obtained
Is applied and baked at 700 ° C to form electrodes.
The lead wire was soldered to obtain a zinc oxide varistor. Table 5
Shows the composition of the sample, and Table 6 shows the evaluation results of the electrical characteristics.

[0064]

[Table 5]

[0065]

[Table 6]

According to Tables 5 and 6, the zinc oxide varistor using the zinc oxide-based porcelain of this embodiment can be sintered even at a low temperature of 900 ° C. to 950 ° C. except for sample number # 209. = Non-linear resistance characteristics are good except for the sample of 0.05 (Sample No. # 201). Absolute rate of change of rise voltage V1mA (△ V1mA / V1mA) both for long-time DC load and for surge When the value was 5% or less, the reliability was excellent. In addition, as shown in Table 6, the variation in the electrical characteristics in the lot was small. Although not shown in Table 6, when the zinc oxide varistor was prepared using the zinc oxide porcelain of the present example, the variation in the electrical characteristics between lots was as small as the variation in the electrical characteristics in the lot. Sample No. # 201 had a large variation in electrical characteristics, was not excellent in the initial non-linear resistance characteristics, and had a large deterioration in characteristics due to a voltage load. In the case of # 209, when the firing temperature was increased, the grain growth progressed and measurement became possible, but no good characteristics were exhibited.

Example 4 B in molar ratio_TwoO_ThreePowder and Bi_TwoO_Three
Powder 1: 2, Bi_TwoO_ThreePowder and Cr_TwoO _ThreePowder of 1:
1 was mixed. Mix these powders in the atmosphere
Below, 5 hours at 370 ° C and 5 hours at 500 ° C respectively
After the heat treatment, the stabilized zirconia
By tail-milling with a ball mill of Nomaron pot
B_TwoO_ThreeAnd Bi_TwoO_ThreeConsisting of B_TwoO_Three/ Bi_TwoO_ThreeSynthetic powder, Bi_TwoO_ThreeAnd Cr_Two
O_ThreeBi consisting of_TwoO_Three/ Cr_TwoO_ThreeA synthetic powder was obtained. ZnO powder,
Said B_TwoO_Three / Bi_TwoO_Three Synthetic powder and Bi_TwoO_ThreePowder and the Bi_TwoO
_Three/ Cr_TwoO_ThreePowder and Co_ThreeO_FourPowder and MnO_Two Powder and NiO powder
And Sb_TwoO_FivePowder and AlOOH powder in a weight ratio of 81.38: 1.2:
2.8: 1.2: 0.954: 0.414: 0.383: 1.3: 0.0024
And pulverized for 18 hours by a wet method.
A sample was prepared in a similar manner to that described above.
800 ℃, 850 ℃, 900 ℃, 950 ℃, 1000 ℃, 1050 ℃, 1100
° C and 1200 ° C were selected. Thus a zinc oxide varistor is obtained
Table 7 shows the composition of the sample, and Table 8 shows the evaluation results of the electrical characteristics.
Is shown.

[0068]

[Table 7]

[0069]

[Table 8]

From Tables 7 and 8, except for # 301 fired at 750 ° C and # 309 fired at 1200 ° C,
The zinc oxide varistor using the zinc oxide-based porcelain of this embodiment has a good non-linear resistance characteristic, and the rate of change of the rising voltage V1mA (△ V1mA / V1mA) with respect to a long-time DC load and a surge. The absolute value of ()) was 5% or less and the reliability was excellent. # 301 was so high that the electrical characteristics could not be measured. In the case of # 309, measurement was impossible because the sintered bodies adhered to each other.

Example 5 B ₂ O ₃ powder and Cr ₂ O ₃ powder (the average particle diameter of each powder was 2 to 3 μm) were mixed in a molar ratio of 3: 1, 2: 1, 1. 1: 1, 1: 2, 1: 3, and B ₂
O ₃ in powder and Cr ₂ O ₃ powder and Y ₂ O ₃ powder (particle diameter of the powder has an average particle size of 1~2μm) 2: 2: 1,1: 1: 1,2: 1: 1 And heat-treated at 500 ° C. for 5 hours in an air atmosphere, followed by tail pulverization with a ball mill of a monomalon pot made of stabilized zirconia to thereby obtain B ₂ O ₃ and Cr.
₂ O ₃ synthetic powder (average particle size about 0.5-1.5 μm) and B ₂ O ₃
A synthetic powder of Cr ₂ O ₃ and Y ₂ O ₃ (average particle size of about 0.5 to 1.5 μm) was obtained. Next, ZnO, the synthetic powder, Bi ₂ O ₃ , Co ₃ O ₄ , Mn
_{O 2, NiO, Sb 2 O} 3, Al (OH) a (CH ₃ COO) _2, in a weight ratio of 81.3
8: 0.5: 3.4: 0.954: 0.414: 0.383: 0.95: 0.0065 were blended and mixed and pulverized for 18 hours by a wet method using a ball mill of a monomalon pot, and a sample was prepared in the same manner as in Example 1. The firing temperature was selected between 900 ° C and 950 ° C.
Thus, a zinc oxide varistor was obtained. Table 9 shows the composition of the sample, and Table 10 shows the evaluation results of the electrical characteristics.

[0072]

[Table 9]

[0073]

[Table 10]

[0074]

As described above with reference to the embodiments,
The zinc oxide porcelain composition of the present invention suppresses the generation of interstitial Zn, which is a cause of instability, and has an excellent stability in which aluminum is added as a donor instead.
It is formed using zinc oxide as a main constituent. as a result,
Varistors made using this zinc oxide porcelain composition have excellent electrical characteristics such as non-linear resistance characteristics from low current range to high current range, and suppress generation of interstitial Zn to apply DC and AC voltage. Also, it is extremely stable against heat. The present invention also provides a method for producing the zinc oxide porcelain composition for a zinc oxide varistor at a high yield, and industrially uses a small amount of a boron oxide-containing compound and a chromium oxide-containing compound, or A material and a device having good characteristics are obtained by uniformly dispersing a chromium oxide-containing compound in a molded body and sintering the same.

In the case of producing the sintered body, after a reducing gas or the like generated at an early stage of the sintering process and harmful to the element is expelled, a boron compound having excellent wettability is applied to the grain boundaries together with bismuth oxide and the like. A phase is formed to reduce open pores, and sintering is performed with shrinkage in a state where closed pores having high oxygen partial pressure oxygen are formed. Even if the firing temperature is lowered,
It is possible to sinter uniformly and to grow a particle size important for the varistor uniformly. Further, even if the sintering temperature is lowered, it can withstand a high current pulse sufficiently and keep high performance.

Further, since the zinc oxide porcelain composition of the present invention can be sintered at a low temperature, it is possible to reduce power consumption during sintering, and at the same time, the furnace material and container of an electric furnace used for sintering. Consumption can be reduced, which can greatly contribute to energy saving and resource saving. Furthermore, some of the zinc oxide porcelain compositions of the present invention sinter even at a temperature lower than the melting temperature of silver, and it becomes possible to form a silver electrode inside these porcelains simultaneously with firing. Was.
As a result, a high-performance laminated zinc oxide varistor having a silver internal electrode can be manufactured. Also, by adjusting the type and amount of the additive, it became clear that a varistor with good characteristics could be obtained even when the firing temperature was lowered to 750 ° C. In the conventional arrester, a heat treatment at 500 ° C. to 600 ° C. was required after firing in order to weaken the adverse effect of interstitial Zn in order to withstand AC power application. Indicates that it is unnecessary.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of a disk-type zinc oxide varistor made using the zinc oxide porcelain composition of Example 1 of the present invention.

FIG. 2 is a schematic cross-sectional view of an arrester-type zinc oxide varistor device prepared using the zinc oxide porcelain composition of Example 4 of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Disc-type zinc oxide varistor 11 Zinc oxide porcelain 12 Electrode 13 Lead wire 20 Zinc oxide varistor device 21 Zinc oxide porcelain 23 Side insulating film 24 Mounting screw hole 25 Ground side terminal 26 Spring 27 Line side terminal 28 Resin tube

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] January 31, 2001 (2001.1.3)
1)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 3

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Claim 4

[Correction method] Change

[Correction contents]

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] Claim 21

[Correction method] Change

[Correction contents]

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0003

[Correction method] Change

[Correction contents]

The rising voltage refers to a voltage between both terminals when a current of 1 mA flows through the varistor, and is represented by V _{1 mA} . The voltage between both terminals when a current of 1 mA is applied to a sample having a thickness of 1 mm is defined as one of the constants of this material.
V _{Expressed in 1mA} / mm. This means a rising voltage per 1 mm thickness of the sample.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction contents]

ZnO—Bi ₂ O ₃ —S in which Cr ₂ O ₃ is added to the above composition
In the b ₂ O ₃ + (CoO, MnO, NiO) + Cr ₂ O ₃ system, the pyrochlore phase reacts with ZnO to form a Bi ₂ O ₃ main component liquid phase.
Although a high temperature of 00 ° C or higher was required, once formed Bi
The liquid phase composed mainly of ₂ O ₃ remained at the grain boundaries stably even after cooling, and did not revert to the pyrochlore phase. And it showed excellent properties as a varistor.

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction contents]

[0011] The excellent electrical characteristics of a zinc oxide varistor means that, for example, a high current generated instantaneously in a circuit due to a small leakage current and a high non-linear resistance index of _{0.1 mA} α _{1 mA} described later. To prevent a high voltage from being generated in the circuit. In addition, the term “excellent in reliability” means that electrical characteristics are deteriorated even when a voltage is applied for a long time, when a power load is applied at a high temperature for a long time, or when a pulse current is applied. And the fact that the original electrical characteristics are maintained. However, the conventional zinc oxide varistor has inherent instability as described below.

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction contents]

Normal zinc oxide contains interstitial zinc atoms, so-called interstitial Zn, between lattice points where zinc and oxygen atoms of zinc oxide crystals are located. The conductivity of zinc oxide is due to electrons excited from these interstitial Zn atoms. One of the biggest problems with conventional zinc oxide varistors is electrical instability. If one of these electrical instabilities continues to apply DC or AC voltage to the device for a long time,
The current is gradually increased due to the deterioration of the VI characteristics, and the other is that when the sintered body of the zinc oxide varistor is subjected to a heat treatment at about 700 ° C., the VI characteristics are rapidly deteriorated.
In the latter case, the leakage current becomes large, and in some cases, it may not be practical. The deterioration of these two VI characteristics is caused by the interstitial in the depletion layer along the grain boundary of zinc oxide particles of the sintered body of zinc oxide varistor.
It is caused by the movement of Zn. When aluminum is not added, in the case of a zinc oxide varistor prepared by a conventional manufacturing method, 2 to 7 × 10 ¹⁷
It is said that there are conduction electrons supplied from the interstitial Zn atoms of about / cm ³ . Experimentally, the number of conduction electrons in ZnO particles in zinc oxide varistors is Muk
ae, Tsuda and Nagasawa ("Capacitance-vs-Voltage Characteristics of ZnO
Varistors ", J. Appl. Phys., 50 [6] 4475-76
(1977)).

[Procedure amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0031

[Correction method] Change

[Correction contents]

Further, in order to achieve the above object,
The zinc oxide porcelain composition of the invention has a zinc oxide (ZnO)
Parts (1 mole) at least cobalt oxide (CoO or Co_TwoO
_ThreeOr Co_ThreeO_Four) And manganese oxide (MnO or MnO)_Two, Or
Mn_TwoO_ThreeOr Mn_ThreeO_Four) And nickel oxide (NiO)
Oxidized 0.3 to 5.0 parts by weight of two or three iron group oxides
Bismuth (Bi_TwoO_Three) 1.2 to 7.0 parts by weight of antimony oxide
(Diantimony trioxide Sb_TwoO_ThreeOr diantimony tetroxide Sb_Two
O_FourOr diantimony pentoxide Sb _TwoO_Five) With 0.1 to 2.0 parts by weight
Boron oxide (B_TwoO_Three) Acid containing 0.03-0.5 parts by weight of component
Boron iodide-containing compounds and chromium oxide (Cr_TwoO_Three) Ingredient 0.05 ~
Chromium oxide-containing composition containing 1.0 parts by weight and aluminum oxide
Minium (Al_TwoO_ThreeA) of 0.0001-0.05 parts by weight
An aluminum compound containing a luminium component;
And germanium oxide (GeO ₂ ), Niobium oxide (Nb
_TwoO_Five), Lead oxide (PbO), silicon oxide (SiO ₂ ), Tin oxide
(SnO_Two), Tantalum oxide (Ta_TwoO_Five), Titanium oxide (Ti
O_Two), Tungsten oxide (WO_Three), And rare earth oxides
With more selected oxides, alone or with other oxides
Both have the composition of forming a compound and adding it
It is.

[Procedure amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0032

[Correction method] Change

[Correction contents]

In order to achieve the above-mentioned object, that is, to provide an element having high performance and excellent stability at low cost,
The zinc oxide porcelain composition of the present invention is more preferably made of zinc oxide (ZnO) 81.38 in order to suppress variations in electrical characteristics.
By weight, at least cobalt oxide (CoO, or Co ₂ O ₃ , or Co ₃ O ₄ ) and manganese oxide (MnO, or MnO ₂ , or Mn ₂ O ₃ ,
Or 0.5 to 4.0 parts by weight of two or three iron group oxides selected from Mn ₃ O ₄ ) and nickel oxide (NiO), 1.2 to 7.0 parts by weight of bismuth oxide (Bi ₂ O ₃ ), and antimony oxide ( oxide containing diantimony trioxide SbrO ₃ or tetroxide antimony Sb ₂ O ₄ or diantimony pentaoxide Sb ₂ O ₅₎ 0.1 to 2.0 parts by weight boron oxide component (B ₂ O ₃₎ 0.05~0.45 parts by weight Chromium oxide-containing composition containing boron-containing composition and chromium oxide component (Cr ₂ O ₃ ) 0.08 to 0.8 parts by weight and aluminum component (0.0003 to 0.02 parts by weight converted to aluminum oxide (Al ₂ O ₃ )) And an aluminum compound to be added, mixed, molded, and fired.

[Procedure amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0041

[Correction method] Change

[Correction contents]

In order to achieve the above object, a zinc oxide varistor according to the present invention provides a zinc oxide varistor comprising at least two or three iron group oxides selected from cobalt oxide, manganese oxide and nickel oxide, bismuth oxide and Antimony (diantimony trioxide or diantimony pentoxide or diantimony pentoxide), a composition containing boron oxide, a composition containing chromium oxide, and an aluminum compound are added and mixed,
It is shaped into a column , fired, cooled and the resulting zinc oxide magnet
At least bismuth oxide and oxide
500 ° C to 800 ° C again after applying a compound containing urine
In which the electrodes are formed on the upper and lower surfaces .

[Procedure amendment 11]

[Document name to be amended] Statement

[Correction target item name] 0048

[Correction method] Change

[Correction contents]

In the zinc oxide porcelain composition of the present invention, in order to secure the priority of the reaction in the firing process, a part of the additives are mixed and heat-treated in advance, and added to the zinc oxide together with other additives. Mold and fire. Further, in the zinc oxide porcelain composition of the present invention, the formation of interstitial Zn, which causes the deterioration of electric characteristics, is prevented, and the zinc oxide is reduced to n.
Aluminum is the sole donor for a type semiconductor. In the firing of zinc oxide porcelain, the chromium oxide added to prevent the formation of the pyrochlore phase at low temperatures and to promote the formation of a liquid phase containing bismuth oxide as a main component at low temperatures reacts with zinc oxide first and reacts with ZnCr. _In order to prevent the formation of ₂ O ₄ , heat treatment is performed in advance with boron oxide, bismuth oxide, antimony oxide, or the like to form a chromium oxide-containing composite, and then added. In the present invention, in order to prevent the formation of interstitial Zn, it is necessary to form an oxygen-excess atmosphere inside the sintered body during sintering,
This is made possible by the addition of iron group oxides that generate oxygen by decomposition and solid solution in zinc oxide. Then, oxygen generated by forming a liquid phase at the grain boundary is confined in the sintered body. Finally, a ZnO-Sb ₂ O ₅ spinel is formed. In these devices, it is necessary to reduce the interstitial Zn and, instead, uniformly dope a small amount of aluminum into the zinc oxide particles to maintain conduction electrons. By efficiently generating closed pores having a high oxygen partial pressure and sintering as if sintering under high-pressure oxygen, an element having high performance and excellent stability could be obtained.

[Procedure amendment 12]

[Document name to be amended] Statement

[Correction target item name] 0050

[Correction method] Change

[Correction contents]

[0050]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Examples. In the following examples, "weight" is
May be displayed as "wt". In each embodiment,
Almost constant aluminum content for easy comparison
And the addition amount of iron group oxide is also added at a fixed rate
And experimented .

[Procedure amendment 13]

[Document name to be amended] Statement

[Correction target item name] 0051

[Correction method] Change

[Correction contents]

Example 1 B ₂ O ₃ powder and Cr ₂ O _{3 in} molar ratio
Was mixed so as to be 1: 1. After subjecting these mixed powders to a heat treatment at 500 ° C. for 5 hours in an air atmosphere,
Monomaron pot ball made of stabilized zirconia
By milling in mill consisting B ₂ O ₃ and Cr ₂ O ₃ B
An rO ₃ / Cr ₂ O ₃ synthetic powder was obtained. ZnO powder and B ₂ O ₃ / C
and r ₂ O ₃ synthetic powder, and Bi ₂ O ₃ powder, and Co ₃ O ₄ powder, and MnO ₂ powder, and NiO powders, and Sb ₂ O ₃ powder, and _{Al (NO 3) 3 · 9H} 2 O powder The weight ratio is 81.38: 0.4: 3.4: 0.954: 0.414: 0.383:
x: It was blended so as to be 0.015, and was mixed and pulverized by a ball mill of a monomalon pot by a wet method. However, x = 0.05, 0.1, 0.2, 0.5, 0.8, 1.0, 1.5, as the amount of Sb ₂ O ₃
2.0 and 3.0 are selected. The obtained compounded powder was dried and pressed into a disk. Next, the temperature of the obtained molded body was raised in the air at a temperature rising rate of 50 ° C./hour, and the temperature was maintained at 900 ° C. for 10 hours. The sample size of the obtained sintered body was 1.2 mm in thickness and 14 mm in diameter. Also, the obtained sintered body was heated at 700 ° C.
For 1 hour.

[Procedure amendment 14]

[Document name to be amended] Statement

[Correction target item name] 0052

[Correction method] Change

[Correction contents]

Next, a method for producing a zinc oxide varistor will be described with reference to FIG. FIG. 1 is a schematic perspective view of a disk-type zinc oxide varistor 10 made using the zinc oxide porcelain composition of the present invention. An aluminum layer (not shown) is formed by spraying aluminum on both surfaces of the sintered body 11 obtained as described above, and then copper is sprayed on the aluminum layer formed on both surfaces. Thus, the electrode 12 was formed. After a lead wire 13 was attached to the electrode 12 by soldering, a porcelain other than the lead wire and an electrode portion were coated with a resin to obtain a zinc oxide varistor.

[Procedure amendment 15]

[Document name to be amended] Statement

[Correction target item name] 0053

[Correction method] Change

[Correction contents]

The electrical characteristics of the zinc oxide varistor thus obtained were evaluated. The initial electrical characteristics include the rise voltage V _1mA / mm (voltage for 1mm thickness between both terminals when 1mA current is applied) and non-linear resistance index _0.1mA
α _{1 mA} (value obtained using V _{1 mA} and V _{0.1 mA} ) was measured (in the following description, the nonlinear resistance index is _{0.1 mA
α1mA} is sometimes simply referred to as α value). The larger the nonlinear resistance index, the greater the surge absorption capacity. In addition, the reliability for DC load was evaluated. In a high temperature atmosphere of 80 ° C., a DC load of 0.5 watts is applied for 500 hours,
Cooling and varistor rise voltage V _1mA change rate △ _V1mA /
V _1mA (DC load change rate) was measured. The smaller the rate of change of the varistor rise voltage V _1mA △ V _1mA / V _1mA , the more stable the electrical characteristics of the zinc oxide varistor, indicating higher reliability.

[Procedure amendment 16]

[Document name to be amended] Statement

[Correction target item name] 0054

[Correction method] Change

[Correction contents]

Further, the reliability of the surge was evaluated. Variation rate of varistor rise voltage V _1mA by applying 8 × 20μsec, 2.5kA pulse 10 times △ V _1mA / V _1mA
( Surge change rate) was measured. Table 1 shows the composition of the sample, and Table 2 shows the evaluation results of the electrical characteristics. The smaller the value of the surge rate, the more stable the electrical characteristics of the zinc oxide varistor and the higher the reliability. In each case, the reliability is high when the absolute value of the change rate is 5% or less. The numerical values indicating the evaluation results of the electrical characteristics indicate the minimum value and the maximum value in the lot.

[Procedure amendment 17]

[Document name to be amended] Statement

[Correction target item name] 0057

[Correction method] Change

[Correction contents]

As shown in Tables 1 and 2, the zinc oxide varistor using the zinc oxide porcelain composition of the present embodiment sinters even at a low temperature of 900 ° C. except for the sample with x = 3.0 (sample number # 009). It has good non-linear resistance characteristics except for the sample of x = 0.05 (Sample No. # 001), and the rate of change of the rising voltage V _1mA for both long-term DC load and _surge . The absolute value of (△ V _1mA / V _1mA ) was 5% or less, indicating excellent reliability. In addition, as shown in Table 2, the variation in the electrical characteristics within the lot was small. Although not shown in Table 2, when the zinc oxide varistor was prepared using the zinc oxide porcelain of the present example, the variation in the electrical characteristics between lots was as small as the variation in the electrical characteristics in the lot. Although the sample # 001 had excellent initial non-linear resistance characteristics, the start-up voltage and the non-linear resistance characteristics varied, and the characteristic deterioration due to voltage load and heat treatment was slightly large. In the case of # 009, when the firing temperature was increased, the grain growth progressed and measurement became possible, but no good characteristics were shown.

[Procedure amendment 18]

[Document name to be amended] Statement

[Correction target item name] 0060

[Correction method] Change

[Correction contents]

The zinc oxide mixed powder obtained by the spray dryer is formed into a columnar shape by a RIP (Rubber Isostatic Press, rubber isostatic press) method, and bismuth borosilicate glass powder and MnO ₂ are formed on the side surfaces of the obtained formed body. And baked at 900 ° C. and 950 ° C. for 10 hours each to obtain columnar zinc oxide porcelains # 101 and # 102. The size of the obtained zinc oxide porcelain was 32 mm in diameter and 28 mm in height. Electrodes were formed by spraying aluminum metal on the upper and lower surfaces of the zinc oxide porcelain, and a mica resin coating was applied to the side surfaces to obtain an arrester-type zinc oxide varistor. V _1mA each V _1mA = 6.05kV and V1mA = 5.94 kV
Met. FIG. 2 shows an arrester-type zinc oxide varistor device 20 made using the zinc oxide porcelain composition of the present invention.
FIG. Element electrodes 22 are formed on both upper and lower surfaces of the zinc oxide porcelain 21 by thermal spraying of aluminum. Further, a side surface insulating film 23 of a mica- resin film made of a mixture of mica and resin is formed on a side surface of the zinc oxide porcelain, and a zinc oxide varistor element is formed by the zinc oxide porcelain, the device electrode, and the side surface insulating film. ing. At the lower part of the zinc oxide varistor element, a ground side terminal 2 having a mounting screw hole 24 is provided.
5, a line side terminal 27 having a screw hole 24 for mounting via a spring 26 is provided, and both terminals and a zinc oxide varistor element are molded in a resin tube 28. Table 4 shows the current-voltage characteristics of the arrester type zinc oxide varistor device.

[Procedure amendment 19]

[Document name to be amended] Statement

[Correction target item name] 0063

[Correction method] Change

[Correction contents]

Example 3 B in molar ratio_TwoO_ThreePowder and Sb_TwoO_Three
2: 1 powder, Cr _TwoO_ThreePowder and Sb_TwoO_Three1: 1 powder
And mixed. These mixed powders are put under air atmosphere,
5 hours at 380 ° C and 5 hours at 600 ° C respectively
After treatment, a monomer that uses stabilized zirconia as a cobblestone
With a long pot ball millFineB by crushing_TwoO_Three
And Sb_TwoO_ThreeConsisting of B_TwoO_Three/ Sb_TwoO_ThreeSynthetic powder, Cr_TwoO_ThreeAnd Sb_TwoO_ThreeYo
Rin Cr_TwoO_Three/ Sb_TwoO_ThreeA synthetic powder was obtained. ZnO powder and the above
B_TwoO_Three / Sb_TwoO_Three Synthetic powder and Bi_TwoO_ThreePowder and the Cr_TwoO_Three/ S
b_TwoO_ThreePowder and Co_ThreeO_FourPowder and MnO_Two Powder, NiO powder, and S
b_TwoO_FourPowder and Al (OH) (CH_ThreeCOO)_TwoAnd the weight ratio of 81.38: x:
4.2: x: 0.954: 0.414: 0.383: 0.5: 0.0065
And pulverized by a wet method for 18 hours.
A zinc oxide sintered body porcelain was prepared in a similar manner. However
Then B_TwoO_Three/ Sb_TwoO_ThreeQuantity and Cr_TwoO_Three/ Sb_TwoO_ThreeX =
0.05, 0.1, 0.2, 0.3, 0.5, 1.0, 2.0, 3.0, 4.
0 was selected. Silver electrode material on both sides of the porcelain thus obtained
Apply and bake at 700 ° C to form electrodes and lead
The wire was soldered to obtain a zinc oxide varistor. Table 5
Table 6 shows the composition of the sample and the results of evaluating the electrical characteristics.

[Procedure amendment 20]

[Document name to be amended] Statement

[Correction target item name] 0066

[Correction method] Change

[Correction contents]

According to Tables 5 and 6, the zinc oxide varistor using the zinc oxide-based porcelain of this embodiment can be sintered even at a low temperature of 900 ° C. to 950 ° C. except for sample number # 209. Except for the sample (Sample No. 201) of = 0.05, the nonlinear resistance characteristics are good, and the rate of change of the rising voltage _V1mA (△ _V1mA / _V1mA ) both for long-time DC load and for surge ) Was 5% or less, indicating excellent reliability. Further, as shown in Table 6, the variation in the electrical characteristics within the lot was small. Although not shown in Table 6, when the zinc oxide varistor was prepared using the zinc oxide porcelain of the present example, the variation in the electrical characteristics between lots was as small as the variation in the electrical characteristics in the lot. Sample No. # 201 had a large variation in electrical characteristics, was not excellent in the initial nonlinear resistance characteristics, and had a large deterioration in characteristics due to a voltage load. In the case of # 209, when the firing temperature was increased, the grain growth progressed and measurement became possible, but no good characteristics were exhibited.

[Procedure amendment 21]

[Document name to be amended] Statement

[Correction target item name] 0067

[Correction method] Change

[Correction contents]

Example 4 B ₂ O ₃ powder and Bi ₂ O _{3 in} molar ratio
1: 2, and the powder of Bi ₂ O _{3 and} the powder of Cr ₂ O ₃ were mixed at a ratio of 1: 1. These mixed powders are put under air atmosphere,
5 hours at 370 ° C., respectively, and subjected to heat treatment for 5 hours at 500 ° C., Bo mono malonic pots stabilized zirconia and cobble - B ₂ O ₃ by milling in mill
And consisting of _{Bi 2 O 3 B 2 O 3} / Bi 2 O 3 synthetic powder to obtain a _{Bi 2 O 3 / Cr 2 O} 3 synthetic powder of Bi ₂ O ₃ and Cr ₂ O _3. ZnO powder and the above
B ₂ O ₃ / Bi ₂ O ₃ synthetic powder, Bi ₂ O ₃ powder, and Bi ₂ O ₃ / C
r ₂ O ₃ powder, Co ₃ O ₄ powder, MnO ₂ powder, NiO powder, S
b ₂ O ₅ powder and AlOOH powder in a weight ratio of 81.38: 1.2: 2.8:
1.2: 0.954: 0.414: 0.383: 1.3: 0.0024 were blended, mixed and pulverized by a wet method for 18 hours, and a sample was prepared in the same manner as in Example 1. The firing temperature is 750 ℃, 800 ℃,
850 ° C, 900 ° C, 950 ° C, 1000 ° C, 1050 ° C, 1100 ° C, 1200
° C was chosen. Thus, a zinc oxide varistor was obtained. Table 7
Table 8 shows the composition of the sample, and Table 8 shows the evaluation results of the electrical characteristics.

[Procedure amendment 22]

[Document name to be amended] Statement

[Correction target item name] 0070

[Correction method] Change

[Correction contents]

From Tables 7 and 8, except for # 301 fired at 750 ° C and # 309 fired at 1200 ° C,
Zinc oxide varistor using the zinc oxide-based ceramics of the present embodiment, nonlinear resistance characteristics good, even for also surges against long-time DC loading, the rate of change in threshold voltage V1mA (△ V _1mA / The absolute value of V _1mA ) was 5% or less, and the reliability was excellent. For # 301, the voltage was too high to measure the electrical characteristics. In the case of # 309, the measurement was impossible because the sintered bodies adhered to each other.

[Procedure amendment 23]

[Document name to be amended] Statement

[Correction target item name] 0071

[Correction method] Change

[Correction contents]

Example 5 B ₂ O ₃ powder and Cr ₂ O ₃ powder (the average particle diameter of each powder was 2 to 3 μm) were mixed in a molar ratio of 3: 1, 2: 1, 1. 1: 1, 1: 2, 1: 3, and B ₂
O ₃ in powder and Cr ₂ O ₃ powder and Y ₂ O ₃ powder (particle diameter of the powder has an average particle size of 1~2μm) 2: 2: 1,1: 1: 1,2: 1: 1 were mixed so that, under an air atmosphere, was subjected to heat treatment for 5 hours at 500 ° C., Bo mono malonic pots stabilized zirconia and cobble - B ₂ O ₃ by milling in mill and Cr
₂ O ₃ synthetic powder (average particle size about 0.5-1.5 μm) and B ₂ O ₃
A synthetic powder of Cr ₂ O ₃ and Y ₂ O ₃ (average particle size of about 0.5 to 1.5 μm) was obtained. Next, ZnO, the synthetic powder, Bi ₂ O ₃ , Co ₃ O ₄ , Mn
_{O 2, NiO, Sb 2 O} 3, Al (OH) a (CH ₃ COO) _2, in a weight ratio of 81.3
8: 0.5: 3.4: 0.954: 0.414: 0.383: 0.95: 0.0065 were blended and mixed and pulverized for 18 hours by a wet method using a ball mill of a monomalon pot, and a sample was prepared in the same manner as in Example 1. did. The firing temperature was selected between 900 ° C and 950 ° C. Thus, a zinc oxide varistor was obtained. Table 9 shows the composition of the sample.
Table 10 shows the evaluation results of the electrical characteristics.

Continued on the front page (72) Inventor Daiki Miyamoto 2-7-1, Ayumino, Izumi-shi, Osaka Inside the Osaka Prefectural Institute of Advanced Industrial Science and Technology (72) Inventor Atsushi Iga 1-14-11, Yamato, Takatsuki-shi, Osaka F-term (Reference) 4G030 AA07 AA11 AA20 AA21 AA22 AA24 AA25 AA28 AA29 AA35 AA36 AA37 AA38 AA39 AA40 AA42 AA43 BA04 GA27 GA33 5E034 CA08 CB01 CC04 DA03 DE07 EA08

Claims (25)

[Claims] 1. A method according to claim 1, wherein 81.38 parts by weight (1 mol) of zinc oxide (ZnO) is mixed with at least cobalt oxide (CoO, or Co ₂ O ₃ , or Co ₃ O ₄ ).
And manganese oxide (MnO, or MnO ₂ , or Mn ₂ O ₃ , or Mn ₃
O ₄ ) and nickel oxide (NiO), 0.3 to 5.0 parts by weight of two or three iron group oxides selected from bismuth oxide (Bi ₂ O
₃₎ a 1.2 to 7.0 parts by weight of antimony oxide (antimony trioxide Sb ₂ O ₃ or tetroxide antimony Sb ₂ O ₄ or diantimony pentaoxide Sb ₂ O ₅₎ 0.1 to 3.0 parts by weight boron oxide (B ₂ O
₃ ) Component containing boron oxide containing 0.03-0.5 parts by weight and chromium oxide (Cr ₂ O ₃ ) component Composition containing chromium oxide containing 0.05-1.0 parts by weight and aluminum oxide (Al ₂ O)
₃ ) A zinc oxide porcelain composition obtained by adding and mixing an aluminum compound containing an aluminum component in an amount of 0.0001 to 0.05 part by weight, molding, and firing. 2. The method of claim 1, wherein at least two or more of the iron group oxides selected from cobalt oxide, manganese oxide and nickel oxide are at least one of the iron group oxides having a valence greater than divalent. The zinc oxide porcelain composition according to claim 1, wherein the zinc oxide porcelain composition is an iron group oxide. 3. The oxidizing composition according to claim 1, wherein the bismuth oxide is 1.2 to 7.0 parts by weight, and the total bismuth component added is 1.2 to 7.0 parts by weight in terms of Bi ₂ O _3. Zinc porcelain composition. 4. An antimony oxide is used in an amount of 0.1 to 3.0 parts by weight, and the total amount of added antimony is 0.1 to 3.0 parts in terms of Sb ₂ O _3.
The zinc oxide porcelain composition according to claim 1, wherein the composition is parts by weight. 5.The zinc oxide porcelain composition according to claim 1, wherein the firing is performed at 800 ° C. to 1100 ° C. 6. The zinc oxide porcelain composition according to claim 1, wherein the firing is performed while forming closed pores containing high-pressure oxygen therein. 7.The zinc oxide porcelain composition according to claim 1, wherein the composition contains closed pores containing high-pressure oxygen. 8. The boron oxide-containing composition is a composition containing at least one to four oxides selected from chromium oxide, bismuth oxide, antimony oxide, and rare earth oxides in addition to boron oxide. A zinc oxide porcelain composition according to claim 1. 9. The chromium oxide-containing compound is a compound containing, in addition to chromium oxide, at least one to four oxides selected from boron oxide, bismuth oxide, antimony oxide and rare earth oxides. A zinc oxide porcelain composition according to claim 1. 10.The zinc oxide porcelain composition according to claim 1, wherein the boron oxide-containing composition and the chromium oxide-containing composition are boron oxide / chromium oxide-containing compositions. 11. A composition containing at least two or three iron group oxides selected from cobalt oxide, manganese oxide and nickel oxide, bismuth oxide, antimony oxide, boron oxide-containing composition, chromium oxide-containing composition and aluminum as zinc oxide. Add the compound and mix, mold, fire and
A zinc oxide porcelain composition containing a γ-bismuth phase as a bismuth oxide phase subjected to a heat treatment at 500 ° C to 800 ° C after cooling. 12.The zinc oxide porcelain composition according to claim 1, wherein a part of zinc oxide as a main component is replaced by magnesium oxide. 13. Zinc oxide may further contain germanium oxide (GeO ₂ ), niobium oxide (Nb ₂ O ₅ ), lead oxide (PbO), silicon oxide (SiO ₂ ), tin oxide (SnO ₂ ), tantalum oxide ( Ta ₂ O
₅ ), titanium oxide (TiO ₂ ), tungsten oxide (WO ₃ ),
The zinc oxide porcelain composition according to claim 1, wherein an oxide selected from the group consisting of a rare earth oxide and an oxide alone or together with another oxide is formed. 14. A step of preparing a boron oxide-containing compound, a step of preparing a chromium oxide-containing compound, and adding two or three iron groups selected from cobalt oxide, manganese oxide and nickel oxide to zinc oxide powder. oxide and bismuth oxide and antimony oxide (antimony trioxide Sb ₂ O ₃ or tetroxide antimony Sb ₂ O ₄ or diantimony pentaoxide Sb ₂ O ₅₎ the boron oxide-containing compound and said chromium oxide-containing compound Adding and mixing an aluminum compound with the mixture to form a zinc oxide mixed powder, forming the zinc oxide mixed powder to form a compact, and firing the compact. A method for producing a zinc oxide porcelain composition. 15. A process for producing a boron oxide-containing composite, comprising: melting at 300 ° C. an oxide mixture of at least one selected from chromium oxide, bismuth oxide, antimony oxide and rare earth oxide in addition to boron oxide. 15. The method for producing a zinc oxide porcelain composition according to claim 14, wherein the heat treatment is performed at any temperature up to a temperature equal to or higher than the temperature to produce a boron oxide-containing composition containing the same. . 16. The step of producing a chromium oxide-containing composite comprises melting from 300 ° C. a mixture of at least 1 to 4 oxides selected from at least boron oxide, bismuth oxide, antimony oxide and rare earth oxides in addition to chromium oxide. The method for producing a zinc oxide porcelain composition according to claim 14, wherein the heat treatment is performed at any temperature up to or above the temperature to prepare a chromium oxide-containing composite containing these. . 17. The step of producing a boron oxide-containing composition and the step of producing a chromium oxide-containing composition are steps of producing a boron oxide / chromium oxide-containing composition,
15. The oxidation method according to claim 14, comprising a step of subjecting the mixture containing boron oxide and chromium oxide to a heat treatment at any temperature from 300 ° C. to a temperature equal to or higher than the melting temperature, and a step of pulverizing the mixture. A method for producing a zinc porcelain composition. 18. The method according to claim 18, wherein the step of firing the molded body includes the step of:
A method for producing a zinc oxide porcelain composition according to claim 14, wherein the firing is performed at a temperature of from 1 ° C to 1100 ° C. 19. A step of preparing a compound containing boron oxide, a step of preparing a compound containing chromium oxide, and two or three iron groups selected from zinc oxide and at least cobalt oxide, manganese oxide and nickel oxide. Adding an oxide, bismuth oxide, antimony oxide, the boron oxide-containing composition, the chromium oxide-containing composition, and an aluminum compound;
Mixing to form a zinc oxide mixed powder; forming the zinc oxide mixed powder to form a molded body; firing the molded body to form a fired product; and Performing a heat treatment at 500 ° C. to 800 ° C. on the zinc oxide porcelain composition. 20. A zinc oxide containing at least two or three iron group oxides selected from cobalt oxide, manganese oxide and nickel oxide, bismuth oxide, antimony oxide, boron oxide containing compound, chromium oxide containing compound and aluminum. Add the compound and mix, mold, fire and
Zinc oxide varistor formed with electrodes. 21. A zinc oxide containing at least two or three iron group oxides selected from cobalt oxide, manganese oxide and nickel oxide, bismuth oxide, antimony oxide, boron oxide containing compound, chromium oxide containing compound and aluminum. A zinc oxide varistor obtained by forming an electrode on a zinc oxide porcelain composition obtained by adding and mixing a compound, molding, firing, cooling, and then performing a heat treatment at 500 ° C to 800 ° C again. 22. A zinc oxide, at least two or three iron group oxides selected from cobalt oxide, manganese oxide and nickel oxide, bismuth oxide, antimony oxide, boron oxide-containing composition, chromium oxide-containing composition and aluminum. A zinc oxide mixed powder is prepared by adding and mixing with a compound, a compact is formed by pressing the zinc oxide mixed powder, and an inorganic insulating film constituent material is applied to a side surface of the compact,
A zinc oxide varistor that forms an electrode by forming a side high resistance layer at the same time as firing. 23. A zinc oxide containing at least two or three iron group oxides selected from cobalt oxide, manganese oxide and nickel oxide, bismuth oxide, antimony oxide, boron oxide containing compound, chromium oxide containing compound and aluminum. A compound is added and mixed to form a zinc oxide mixed powder, a pressed body is formed on the zinc oxide mixed powder to form a molded body, an electrode material is applied to two surfaces of the molded body, and fired at the same time. Zinc oxide varistor formed with electrodes. 24. A zinc oxide containing at least two or three iron group oxides selected from cobalt oxide, manganese oxide and nickel oxide, bismuth oxide, antimony oxide, boron oxide containing compound, chromium oxide containing compound and aluminum. A laminated zinc oxide varistor obtained by adding and mixing a compound, forming a thin plate, alternately laminating the obtained molded body and metal electrode material, and firing. 25. A zinc oxide containing at least two or three iron group oxides selected from cobalt oxide, manganese oxide and nickel oxide, bismuth oxide, antimony oxide, boron oxide containing compound, chromium oxide containing compound and aluminum. A compound is added, mixed, molded, and fired to obtain a zinc oxide porcelain composition, the side surfaces of the zinc oxide porcelain composition are covered with an insulating film, and two sides of the zinc oxide porcelain composition are further added. A zinc oxide varistor device obtained by forming an electrode on a single zinc oxide varistor and enclosing the single zinc oxide varistor or a plurality of zinc oxide varistors in an insulating container.