JPH0967161A - Zinc oxide ceramic composition and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain excellent electric characteristics by adding a synthesized powder containing a Bi2 O3 powder and a Sb2 O3 powder, which is heat treated at a specified temp., and at least one kind of powder selected from cobalt oxide and manganese oxide to a ZnO powder. SOLUTION: A Bi2 O3 powder and a Sb2 O3 powder are prepared by mixing a boron compd. powder such as B2 O3 and/or a chromium oxide powder such as Cr2 O3 in a specified proportion, heat treating at 400 to 700 deg.C in air, and then finely pulverizing to produce a synthesized powder having 0.05 to 10μm average particle size. Then, a ZnO powder by 100 pts.wt. containing an Al component by 0.00062 to 0.372 pts.wt. calculated as Al2 O3 and 0.5 to 20 pts.wt. of the synthesized powder (0.49-19.99 pts.wt. of the Bi2 O3 powder and 0.01 to 10 pts.wt. of the Sb2 O3 powder), and a cobalt powder such as CoO and/or a manganese oxide powder such as MnO2 by 0.1 to 5 pts.wt. are compounded. The compounded material is mixed in a ball mill or the like to obtain a ZnO ceramic compsn., which is compacted under pressure. The compacted body is fired at about 750 to 1100 deg.C to obtain a sintered body.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a zinc oxide porcelain composition and a method for producing the same. More specifically, the present invention relates to a zinc oxide porcelain composition for producing a zinc oxide varistor used for absorbing surges in an electric circuit and a method for producing the same.

[0002]

2. Description of the Related Art A zinc oxide (ZnO) varistor is a zinc oxide raw material containing zinc oxide, basic additives bismuth oxide, manganese dioxide and cobalt oxide, and various oxides added to further improve performance. It is manufactured using a sintered body of a zinc oxide-based porcelain composition obtained by firing the powder. The rising voltage of a zinc oxide varistor is
It is known that the number of grain boundaries existing between electrodes rises almost in proportion to the number of grain boundaries. That is, 3 to 4 per grain boundary
Volt rise voltage rises. Therefore, in order to manufacture a zinc oxide varistor for high voltage, an average particle size of 4-4
It is necessary to manufacture a sintered body having ZnO particles having a small particle size of about 0 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 growth inhibitor for ZnO particles such as antimony oxide (Sb ₂ O ₃ ) is used. Came.

The rising voltage is 1 m for a varistor.
It is the voltage between both terminals when the current of A is passed and is expressed by V _1mA . The voltage between terminals when a current of 1 mA was applied to a sample with a thickness of 1 mm was defined as one of the constants of this material, and V
It is expressed in _{1mA / mm} . This is the rising voltage per 1 mm thickness of the sample.

[0004]

However, in order to obtain a high-performance, high-performance zinc oxide varistor for a high voltage, 1150 ° C.
High sintering temperatures of ~ 1300 ° C were required. A high sintering temperature causes not only power consumption but also vigorous scattering of bismuth oxide and the like and consumption of a furnace material and a container, and a reduction in sintering temperature has been demanded. That is, when firing at these high temperatures, evaporation of bismuth oxide or the like is active even in the atmosphere. In addition, bismuth oxide easily reacts with many substances, and easily corrodes many substances such as ceramics such as furnace materials and containers. On the other hand, when the firing temperature is lowered with the compounding composition of the zinc oxide porcelain composition for manufacturing the conventional zinc oxide varistor, the rising voltage sharply increases and the particle diameter of ZnO varies and the nonlinear resistance characteristic deteriorates. To do. Further, the life is shortened with respect to a power load, a pulse current load, and the like.

Further, in the conventional manufacturing method, since all components to be blended such as bismuth oxide, antimony oxide, chromium oxide, or boron oxide are mixed as they are with the zinc oxide raw material powder and baked, a complicated reaction occurs. , There is a portion where antimony oxide and zinc oxide react first, a portion where bismuth oxide and antimony oxide react first, and the like. In addition, boron oxide tends to form a liquid phase early in the temperature rising process and collect, which tends to cause non-uniform quality and cause quality variations. In particular, antimony oxide easily sublimes the surface of zinc oxide particles and reacts with ZnO to suppress grain growth. As a result, in the sintered body, a portion where the grain growth is not promoted and a portion where the grain growth is promoted coexist, and it is difficult to produce a sintered body having a uniform grain size by the conventional manufacturing method. It was Therefore, non-uniformity in quality and variation in quality between lots are likely to occur.

Further, since it was difficult to sufficiently control the abnormal grain growth of ZnO, there are large variations in electrical characteristics and reliability among zinc oxide varistors obtained from one manufacturing lot (variations within lots). There was a problem. Further, there is a problem that variations in electrical characteristics and reliability among zinc oxide varistors obtained from different manufacturing lots (variations between lots) are also large.

As described above, the conventional method using a porcelain composition could not stably produce a zinc oxide varistor of low temperature sintering excellent in electrical characteristics and reliability. Incidentally, the zinc oxide varistor having excellent electric characteristics means, for example, that the leakage current is small and the nonlinear resistance index _{0.1 mA} α _{1 mA} described later is high.
There are matters such as no deterioration in electrical characteristics when a voltage is applied for a long time, when a power is loaded at a high temperature for a long time, or when a pulse is applied.

In order to solve the above problems, the present invention provides a zinc oxide porcelain composition for producing a high yield of zinc oxide varistor which is excellent in electrical characteristics such as non-linear resistance characteristics and reliability by low temperature sintering. And its manufacturing method.

[0009]

In order to achieve the above object, the zinc oxide porcelain composition of the present invention comprises a zinc oxide powder 1
0.5 to 20 parts by weight of a synthetic powder prepared by subjecting a mixture of at least bismuth oxide powder and antimony oxide powder to a heat treatment at 400 ° C. to 700 ° C. with respect to 100 parts by weight of cobalt oxide and manganese oxide. A composition comprising 0.1 to 5.0 parts by weight of at least one powder selected.

In this way, a mixture of at least bismuth oxide powder and antimony oxide powder is previously prepared at 400 ° C.
By heat-treating at 700 ° C. and adding as a synthetic powder, the effect of antimony oxide on the inhibition of sintering of zinc oxide powder is mitigated, and even if it is fired at a lower temperature, sufficient sintering is possible and the particle size is uniform. Can be a sintered body,
A zinc oxide porcelain composition capable of producing a zinc oxide varistor excellent in electrical characteristics such as nonlinear resistance characteristics and reliability by low-temperature sintering with a high yield can be provided.

In the zinc oxide porcelain composition of the present invention, the synthetic powder comprises bismuth oxide powder, antimony oxide powder, boron oxide (B ₂ O ₃ ) and boric acid (H ₃ BO ₃ ). It is preferable that the mixture containing at least one selected boron compound powder is a synthetic powder prepared by heat treatment at 400 ° C. to 700 ° C.

The boron compound powder further promotes the action of lowering the sintering temperature. In the zinc oxide porcelain composition of the present invention, the synthetic powder is prepared by subjecting a mixture of bismuth oxide powder, antimony oxide powder and chromium oxide powder to heat treatment at 400 ° C to 700 ° C. It is preferable that the synthetic powder is

Antimony oxide reacts with bismuth oxide to form a pyrochlore phase, which may remain under cooling conditions. However, by adding chromium oxide, antimony oxide is used to form a spinel phase. , Which contributes to the stabilization of the phase, and thus can be a sintered body with stable quality.

In the zinc oxide porcelain composition of the present invention, the synthetic powder is bismuth oxide powder, antimony oxide powder, chromium oxide powder, and boron oxide (B ₂ O ₃
) And at least one boron compound powder selected from boric acid (H ₃ BO ₃ ), 400 ° C. to 700 ° C.
It is preferable that the synthetic powder is prepared by subjecting to the heat treatment of 1.

According to this mode, the action of lowering the sintering temperature by the boron compound powder and the action of stabilizing the phase by the chromium oxide are exhibited. Further, in the zinc oxide porcelain composition of the present invention, a mixture of bismuth oxide powder and antimony oxide powder is 400 ° C.
A synthetic powder prepared by heat treatment at 700 ° C.,
Bismuth oxide powder and boron oxide (B ₂ O ₃ ) and boric acid (H ₃
It is preferable to use two kinds of synthetic powders, a synthetic powder prepared by subjecting a mixture with at least one boron compound powder selected from BO ₃ ) to a heat treatment at 400 ° C to 700 ° C.

The boron compound has a function of lowering the sintering temperature, but when used as it is, it forms a liquid phase at a low temperature,
They tend to collect and tend to homogenize the resulting sintered body. By reacting the bismuth oxide and the boron compound in advance, this drawback can be improved and, at the same time, the effect of improving compatibility with other bismuth oxide-based compounds is exhibited.

Further, in the zinc oxide porcelain composition of the present invention, a synthetic powder prepared by subjecting a mixture of bismuth oxide powder and antimony oxide powder to heat treatment at 400 ° C. to 700 ° C. It is preferable to use two kinds of synthetic powders, that is, a synthetic powder prepared by subjecting a mixture of bismuth oxide powder and chromium oxide powder to heat treatment at 400 ° C. to 700 ° C.

Chromium oxide contributes to reducing variations in the quality of zinc oxide varistors and improving electrical characteristics and reliability, but is toxic if the proportion of bismuth oxide in the reaction with bismuth oxide is high. Since valent chromium is generated, the required amount of bismuth oxide is divided into two so that the amount of bismuth oxide when reacting with chromium oxide is reduced.

In the zinc oxide porcelain composition of the present invention, a synthetic powder prepared by subjecting a mixture of bismuth oxide powder and antimony oxide powder to heat treatment at 400 ° C. to 700 ° C. And a mixture of bismuth oxide powder and at least one boron compound powder selected from boron oxide (B ₂ O ₃ ) and boric acid (H ₃ BO ₃ ).
40 ° C. to a synthetic powder prepared by being subjected to a heat treatment at ℃ to 700 ° C. and a mixture of bismuth oxide powder and chromium oxide powder.
It is preferable to use three kinds of synthetic powders, which are a synthetic powder prepared by being subjected to a heat treatment at 0 ° C to 700 ° C.

By using these three kinds of synthetic powders, the action and effect obtained by using the respective synthetic powders described above are exhibited, and the amounts of antimony oxide, boron compound and chromium oxide can be easily adjusted. It is extremely preferable in terms of production control.

In the zinc oxide porcelain composition of the present invention, a mixture of bismuth oxide powder, antimony oxide powder and chromium oxide powder is 400 ° C. or more as a synthetic powder.
A synthetic powder prepared by heat treatment at 700 ° C.,
Bismuth oxide powder and boron oxide (B ₂ O ₃ ) and boric acid (H ₃ BO
It is preferable to use two kinds of synthetic powders, that is, a synthetic powder prepared by subjecting a mixture with at least one boron compound powder selected from ₃ ) to heat treatment at 400 ° C to 700 ° C.

Although the boron compound has the effect of lowering the sintering temperature, it tends to make the sintered body inhomogeneous. By reacting the bismuth oxide with the boron compound in advance, this defect is improved and the uniformity is improved. It is preferable to obtain a zinc oxide varistor which can obtain a good sintered body and has excellent electrical characteristics and high reliability in combination with the homogenizing effect of chromium oxide.

In the zinc oxide porcelain composition of the present invention, the bismuth oxide powder, antimony oxide powder, boron oxide (B ₂ O ₃ ) and boric acid (H ₃ BO ₃ ) are used as synthetic powders.
A mixture of at least one boron compound powder selected from the above is prepared by heat treatment at 400 ° C to 700 ° C, and a mixture of bismuth oxide powder and chromium oxide powder is subjected to heat treatment at 400 ° C to 700 ° C. It is preferable to use two kinds of synthetic powders, that is, a synthetic powder prepared by the above method.

This embodiment utilizes the function of preventing the inhomogeneity of the sintered body due to the boron compound in advance and lowering the sintering temperature, and, in combination with the homogenizing action of chromium oxide, the electrical characteristics and reliability with little variation in quality. It is preferable to obtain a zinc oxide varistor having good properties. It is also preferable for reducing the generation of toxic hexavalent chromium.

Further, in the zinc oxide porcelain composition of the present invention, a synthetic powder prepared by subjecting a mixture of bismuth oxide powder and antimony oxide powder to heat treatment at 400 ° C. to 700 ° C. , Bismuth oxide powder, chromium oxide powder, boron oxide (B ₂ O ₃ ) and boric acid (H ₃ BO
It is preferable to use two kinds of synthetic powders, that is, a synthetic powder prepared by subjecting a mixture with at least one boron compound powder selected from ₃ ) to heat treatment at 400 ° C to 700 ° C.

This embodiment utilizes the function of lowering the sintering temperature by the boron compound, and in combination with the homogenizing action by chromium oxide, it is possible to obtain a zinc oxide varistor with excellent electrical characteristics and high reliability. preferable. It is also preferable for reducing the generation of toxic hexavalent chromium.

In the zinc oxide-based porcelain composition of the present invention, the aluminum component is zinc oxide powder 10.
0.000 in terms of aluminum oxide with respect to 0 part by weight
It is preferable that the content is 62 to 0.372 parts by weight.

In this embodiment, the added aluminum component forms a solid solution in the ZnO particles and acts as a donor of the semiconductor, so that the electrical resistance of ZnO can be reduced to a preferable level without impairing other electrical characteristics. Can
A zinc oxide-based porcelain composition suitable for improving the non-linear resistance characteristic of a varistor in a high current region can be provided.

Further, in the zinc oxide porcelain composition of the present invention, when a synthetic powder prepared by subjecting a mixture of bismuth oxide powder and chromium oxide powder to heat treatment at 400 ° C. to 700 ° C. is used. In this case, the mixing ratio of the bismuth oxide powder and the chromium oxide powder is preferably such that the molar ratio of the chromium oxide powder to the bismuth oxide powder is equal to or more.

As described above, chromium oxide contributes to reducing the variation in the quality of the zinc oxide varistor and improving the electrical characteristics and reliability, but the proportion of bismuth oxide in the reaction with bismuth oxide is small. Toxic hexavalent chromium is generated if it is too much. Therefore, the generation of toxic hexavalent chromium was prevented by making the amount of chromium oxide when reacting with bismuth oxide equal to or more than the amount of bismuth oxide. It is a thing.

In the zinc oxide porcelain composition of the present invention, at least one boron compound powder selected from bismuth oxide powder, boron oxide (B ₂ O ₃ ) and boric acid (H ₃ BO ₃ ). In the case of using a synthetic powder prepared by subjecting the mixture of the above to a heat treatment at 400 ° C. to 700 ° C., bismuth oxide powder, boron oxide (B ₂ O ₃ ) and boric acid are used.
The mixing ratio of at least one boron compound powder selected from (H ₃ BO ₃ ) is preferably 80:20 to 20:80 in terms of molar ratio.

By setting the composition in such a range, it is possible to lower the sintering temperature while keeping the grain size well, to stabilize the sintering process, and to reduce the variation in the quality of the sintered body within the lot. It is possible to provide a zinc oxide-based porcelain composition capable of obtaining a sintered body having a higher yield.

Further, according to the invention of the method for producing a zinc oxide porcelain composition of the present invention, a mixture of at least bismuth oxide powder and antimony oxide powder is subjected to heat treatment at 400 ° C. to 700 ° C. and crushed to obtain a synthetic powder. The step of adjusting, and 0.5 to 20 parts by weight of the synthetic powder, zinc oxide powder 100
Adding to a raw material powder containing 0.1 to 5 parts by weight of at least one powder selected from cobalt oxide powder and manganese oxide powder.

In the invention of the production method of the present invention, at least a mixture of bismuth oxide powder and antimony oxide powder is heat-treated at 400 ° C. to 700 ° C. in advance and added as a synthetic powder to obtain zinc oxide powder of antimony oxide. The sintering inhibiting effect of the above is alleviated, and even if it is fired at a lower temperature, sufficient sintering is possible, and it is possible to obtain a sintered body with a uniform grain size. It is possible to provide a method for producing a zinc oxide-based porcelain composition for producing a zinc oxide varistor excellent in electrical characteristics and reliability with high yield.

In the method for producing the zinc oxide porcelain composition of the present invention, as the synthetic powder, bismuth oxide powder, antimony oxide powder, boron oxide (B ₂ O ₃ ) and boric acid (H _{3) are used.}
It is preferable to use a synthetic powder obtained by subjecting a mixture containing at least one boron compound powder selected from BO ₃ ) to a heat treatment at 400 ° C. to 700 ° C. and pulverizing the mixture.

The boron compound powder further promotes the action of lowering the sintering temperature. In addition, in the method for producing a zinc oxide-based porcelain composition of the present invention, a mixture of bismuth oxide powder, antimony oxide powder, and chromium oxide powder is subjected to heat treatment at 400 ° C. to 700 ° C. and pulverized as a synthetic powder. It is preferable to use the synthetic powder obtained in this way.

Antimony oxide reacts with bismuth oxide to form a pyrochlore phase, which may remain under cooling conditions. However, by adding chromium oxide, antimony oxide is used to form a spinel phase. It is possible to provide a method for producing a zinc oxide-based porcelain composition, which contributes to the stabilization of the phase and thus can be a sintered body of stable quality.

In the method for producing the zinc oxide porcelain composition of the present invention, as the synthetic powder, bismuth oxide powder, antimony oxide powder, chromium oxide powder, and boron oxide (B ₂ O ₃ ). And at least one boron compound powder selected from boric acid (H ₃ BO ₃ ).
It is preferable to use a synthetic powder obtained by crushing by heat treatment at 0 ° C to 700 ° C.

By adopting this mode, it is possible to provide a method for producing a zinc oxide-based porcelain composition which can exhibit the effect of lowering the sintering temperature by the boron compound powder and the effect of stabilizing the phase by chromium oxide.

In the method for producing a zinc oxide porcelain composition of the present invention, a mixture of bismuth oxide powder and antimony oxide powder is used as a synthetic powder at 400 ° C. to 700 ° C.
A mixture of synthetic powder obtained by subjecting to pulverization by heat treatment at ℃, and bismuth oxide powder and at least one boron compound powder selected from boron oxide (B ₂ O ₃ ) and boric acid (H ₃ BO ₃ ) is used. It is preferable to use two kinds of synthetic powders, that is, a synthetic powder obtained by performing heat treatment at ℃ to 700 ° C and pulverizing.

The boron compound has a function of lowering the sintering temperature, but when used as it is, it forms a liquid phase at a low temperature,
They tend to collect and tend to homogenize the resulting sintered body. By reacting the bismuth oxide and the boron compound in advance, this drawback can be improved and, at the same time, the effect of improving compatibility with other bismuth oxide-based compounds is exhibited.

In the method for producing a zinc oxide ceramic composition according to the present invention, a mixture of bismuth oxide powder and antimony oxide powder is used as a synthetic powder at 400 ° C. to 700 ° C.
A mixture of bismuth oxide powder and chromium oxide powder, which is obtained by pulverizing the powder by heat treatment at 400 ° C, is heated at 400 ° C to 7 ° C.
It is preferable to use two kinds of synthetic powders, that is, a synthetic powder obtained by performing heat treatment at 00 ° C. and pulverizing.

Chromium oxide contributes to reducing the variation in the quality of the zinc oxide varistor and improving the electrical characteristics and reliability, but is toxic if the proportion of bismuth oxide is large when it reacts with bismuth oxide. Since valent chromium is generated, the required amount of bismuth oxide is divided into two so that the amount of bismuth oxide when reacting with chromium oxide is reduced.

In the method for producing a zinc oxide porcelain composition according to the present invention, a mixture of bismuth oxide powder and antimony oxide powder is used as a synthetic powder at 400 ° C to 700 ° C.
A mixture of synthetic powder obtained by subjecting to pulverization by heat treatment at ℃, and bismuth oxide powder and at least one boron compound powder selected from boron oxide (B ₂ O ₃ ) and boric acid (H ₃ BO ₃ ) is used. Three kinds of synthetic powders obtained by heat-treating at ℃ to 700 ℃ and crushing, and synthetic powders obtained by heat-treating a mixture of bismuth oxide powder and chromium oxide powder at 400 ℃ to 700 ℃ and crushing. Preference is given to using synthetic powders.

By using these three kinds of synthetic powders, the action and effect obtained by using the respective synthetic powders described above can be exhibited, and the amounts of antimony oxide, boron compound and chromium oxide can be easily adjusted. It is extremely preferable in terms of production control.

Further, in the method for producing the zinc oxide porcelain composition of the present invention, a mixture of bismuth oxide powder, antimony oxide powder and chromium oxide powder is heat-treated at 400 ° C. to 700 ° C. as a synthetic powder. Of a bismuth oxide powder and at least one boron compound powder selected from boron oxide (B ₂ O ₃ ) and boric acid (H ₃ BO ₃ ) at 400 ° C. to 700 ° C. It is preferable to use two kinds of synthetic powders, that is, a synthetic powder obtained by heat treatment and pulverization.

Although the boron compound has the effect of lowering the sintering temperature, it tends to make the sintered body inhomogeneous, and by reacting the bismuth oxide and the boron compound in advance, this defect is improved and the uniformity is improved. Of a preferable zinc oxide porcelain composition for obtaining a zinc oxide varistor which is capable of obtaining a stable sintered body, and has an electric characteristic with less variation in quality in combination with a homogenizing action by chromium oxide and a good reliability. A method can be provided.

In the method for producing the zinc oxide porcelain composition of the present invention, bismuth oxide powder, antimony oxide powder, boron oxide (B ₂ O ₃ ) and boric acid (H ₃ BO) are used as synthetic powders. The mixture of at least one boron compound powder selected from ₃ ) is subjected to heat treatment at 400 ° C. to 700 ° C. and pulverized, and a mixture of bismuth oxide powder and chromium oxide powder is mixed at 400 ° C. to 700 ° C. It is preferable to use two kinds of synthetic powders, that is, a synthetic powder obtained by heat treatment and pulverization.

By adopting this mode, it is possible to prevent inhomogeneity of the sintered body due to the boron compound in advance and to utilize the function of lowering the sintering temperature, and in combination with the homogenizing action by chromium oxide, there is little variation in quality of electricity. It is possible to provide a preferable method for producing a zinc oxide porcelain composition for obtaining a zinc oxide varistor having good characteristics and reliability. It is also preferable for reducing the generation of toxic hexavalent chromium.

In the method for producing a zinc oxide porcelain composition of the present invention, a mixture of bismuth oxide powder and antimony oxide powder is used as a synthetic powder at 400 ° C to 700 ° C.
Synthetic powder obtained by subjecting to pulverization by heat treatment at ℃, bismuth oxide powder, chromium oxide powder, and at least one boron compound powder selected from boron oxide (B ₂ O ₃ ) and boric acid (H ₃ BO ₃ ). It is preferable to use two kinds of synthetic powders, which are a synthetic powder obtained by subjecting the mixture to a heat treatment at 400 ° C to 700 ° C and pulverizing.

By adopting this mode, the function of lowering the sintering temperature by the boron compound is utilized, and in combination with the homogenizing action by chromium oxide, a zinc oxide type varistor with less variation in quality and good reliability is obtained. It is possible to provide a method for producing a zinc oxide-based porcelain composition which is preferable for obtaining the composition. It is also preferable for reducing the generation of toxic hexavalent chromium.

In the method for producing a zinc oxide-based porcelain composition according to the present invention, the raw material powder containing zinc oxide powder to which synthetic powder is added as a main component is further added with 100 parts by weight of zinc oxide powder. It is preferable to add 0.00062 to 0.372 parts by weight in terms of aluminum oxide with respect to parts.

By adding a small amount of the aluminum component, the added aluminum component forms a solid solution in the ZnO particles and acts as a donor of the semiconductor, so that the electrical resistance of ZnO is preferable to the extent not impairing other electrical characteristics. It is possible to provide a method for producing a zinc oxide-based porcelain composition suitable for improving the non-linear resistance characteristic of a varistor in a high current region, which can be reduced to the above.

In the method for producing the zinc oxide porcelain composition of the present invention, a synthetic powder obtained by subjecting a mixture of bismuth oxide powder and chromium oxide powder to heat treatment at 400 ° C. to 700 ° C. and pulverizing When used, the mixing ratio of the bismuth oxide powder and the chromium oxide powder is preferably such that the chromium oxide powder is equimolar or more with respect to the bismuth oxide powder in a molar ratio.

As described above, chromium oxide contributes to reducing the variation in the quality of the zinc oxide varistor and improving the electrical characteristics and reliability, but the proportion of bismuth oxide in the reaction with bismuth oxide is small. Toxic hexavalent chromium is generated if it is too much. Therefore, the generation of toxic hexavalent chromium was prevented by making the amount of chromium oxide when reacting with bismuth oxide equal to or more than the amount of bismuth oxide. It is a thing.

In the method for producing the zinc oxide porcelain composition of the present invention, at least one boron selected from bismuth oxide powder, boron oxide (B ₂ O ₃ ) and boric acid (H ₃ BO ₃ ). When using a synthetic powder obtained by subjecting a mixture with a compound powder to heat treatment at 400 ° C. to 700 ° C. and pulverizing the mixture, bismuth oxide powder, boron oxide (B ₂ O ₃ ) and boric acid (H ₃ BO) are used. The mixing ratio with at least one boron compound powder selected from ₃ ) is preferably 80:20 to 20:80 in terms of molar ratio.

By setting the composition within such a range, it is possible to lower the sintering temperature while keeping the grain size well, to stabilize the sintering process, and to reduce the variation in the quality of the sintered body within the lot. It is possible to provide a method for producing a zinc oxide-based porcelain composition, which can provide a sintered body with improved yield.

[0058]

BEST MODE FOR CARRYING OUT THE INVENTION As described above, in the zinc oxide porcelain composition and the method for producing the same of the present invention, at least bismuth oxide and antimony oxide are heat-treated and pulverized with respect to 100 parts by weight of zinc oxide powder. 0.5 powder
˜20 parts by weight, 0.1 to 5 parts by weight of at least one powder selected from cobalt oxide and manganese oxide is added.

Here, the synthetic powder includes bismuth oxide and oxide.
In addition to antimony, boron oxide and chromium oxide
It may be added if necessary. With cobalt oxide
Is the chemical formula CoO or Co_ThreeO_FourOxidized Cobal
Can be preferably used. Chemical formula M for manganese oxide
nO, Mn₂O_ThreeOr MnO ₂ Manganese oxide
Can be preferably used. In addition, it decomposes at high temperature and is oxidized
Manganese carbonate (MnCO)_Three ) Is also suitable
You. These cobalt and manganese components form a solid solution in zinc oxide.
Part of it is at the grain boundary of zinc oxide particles, resulting in depletion
Since a layer is formed, when using a zinc oxide varistor,
Non-linear resistance index _0.1mAα_1mAActs to enhance.

In addition to bismuth oxide and antimony oxide, boron oxide, chromium oxide, etc. may be added to the synthetic powder as required. The average particle size of the synthetic powder is preferably in the range of 0.05 to 10 μm. The range of 1 μm or less is particularly preferable, but it takes time to pulverize.

Further, in the present invention, the addition amount of the bismuth component is preferably 0.49 to 19.99 parts by weight in terms of Bi ₂ O _{3 with} respect to 100 parts by weight of zinc oxide. Further, in the above-mentioned constitution, the addition amount of the antimony component is 0.01 to 100 parts by weight of zinc oxide in terms of Sb ₂ O _3.
It is preferably 10 parts by weight.

When the chromium oxide powder is used in the present invention, the addition amount of the chromium component is preferably 0.005 to 0.5 parts by weight in terms of Cr ₂ O _{3 with} respect to 100 parts by weight of zinc oxide.

In the present invention, boron oxide or boric acid can be preferably used as the boron oxide. The addition amount of the boron component is preferably in the range of 0.002 to 1.000 parts by weight in terms of B ₂ O _{3 with} respect to 100 parts by weight of zinc oxide.

When an aluminum component is further added in the present invention, the aluminum component is added to aluminum oxide (Al ₂
It is preferable to add 0.00062 to 0.372 parts by weight in terms of O ₃ ).

In the method for producing a zinc oxide porcelain composition of the present invention, a composition containing at least bismuth oxide and antimony oxide is heat-treated and ground to prepare a synthetic powder, and the synthetic powder is oxidized. Zinc is further added as a first component to a raw material powder containing a second component which is at least one powder selected from cobalt oxide and manganese oxide to prepare a blended powder. Here, the raw material powder means a powder containing zinc oxide as a first component and at least a second component which is at least one powder selected from cobalt oxide and manganese oxide, and may be a pulverized powder. In addition to the first and second components, Ni, Mg, S
It may contain components such as i, Ti, Ta, Ge, and Nb. Further, the compounded powder refers to a mixture of synthetic powder and raw material powder.

Further, in the method of manufacturing the zinc oxide porcelain composition of the present invention, in the embodiment in which the two kinds of synthetic powders as described above are used, the step of pulverizing the synthetic powders is performed by heat treating each of the plural synthetic powders. Then, the powders may be crushed separately, or the heat-treated powders may be combined and crushed at the same time.

Further, in the method of producing the zinc oxide porcelain composition of the present invention, in the embodiment using the above-mentioned three kinds of synthetic powders, the raw material mixture for each synthetic powder is heat treated at 400 to 700 ° C. It is preferable to prepare three kinds of synthetic powders by crushing and pulverize them, and then mix the first to third synthetic powders and add them to the raw material powders to adjust the compounded powder.
Here again, in the step of pulverizing the synthetic powder, the third heat treated product for synthetic powder may be pulverized alone and then the first and second heat treated products for synthetic powder may be mixed with the pulverized product, or heat treated. The heat-treated products for each synthetic powder may be combined and ground at the same time, or may be ground separately.

When the synthetic powder is prepared, it is necessary to perform the heat treatment at a temperature of 400 to 700 ° C. If the temperature is lower than this, the reaction of each component constituting the synthetic powder is not sufficient, and the synthetic powder is preliminarily heat treated to obtain the synthetic powder. The effect of doing is not fully exerted. That is, when a synthetic powder having a heat treatment temperature of less than 400 ° C. is used, it is difficult to control the grain growth of zinc oxide, and it is not possible to manufacture a sintered body of uniform quality with a uniform grain size at a low temperature. Further, if the heat treatment temperature is too high, it becomes hard and crushing becomes difficult. Practically preferable heat treatment time is about 10 minutes to 5 hours.

When the zinc oxide porcelain composition of the present invention is produced, it is preferable to include a step of adding the synthetic powder to the raw material powder and then further pulverizing the powder. According to the zinc oxide-based ceramic composition of the present invention, zinc oxide powder 10
0.5 to 20 parts by weight of a synthetic powder obtained by heat-treating a mixture containing at least bismuth oxide and antimony oxide, and 0.1 to 0 parts by weight of at least one powder selected from cobalt oxide and manganese oxide. By adding 5 parts by weight, a porcelain composition that can be sintered at a temperature sufficiently lower than the conventional firing temperature (1200 to 1300 ° C) of 1100 ° C or less can be achieved. If the synthetic powder is less than 0.5 parts by weight based on 100 parts by weight of the zinc oxide powder, the obtained zinc oxide varistor has a low rising voltage, and the rising voltage of the rising voltage of The absolute value of the rate of change is large. In addition, any electrical characteristics will be greatly varied, which is not preferable. Further, when firing for manufacturing a zinc oxide varistor, in order to save energy, it is common to stack a plurality of sample molded bodies in a firing furnace and fire so that as many samples as possible are fired. However, if the amount of the synthetic powder used exceeds 20 parts by weight, the sample will stick to each other during firing, making it difficult to produce the desired zinc oxide varistor. In order to obtain a sintered body having a uniform particle size, the average particle size of the synthetic powder is 0.05 to 10
It is preferably in the range of μm. Further, as the raw material powder containing zinc oxide powder or the like, those having an average particle diameter of 0.05 to 5.0 μm can be suitably used.

Further, in the case of using the synthetic powder obtained by subjecting the mixture of the bismuth oxide powder and the chromium oxide powder mentioned above to the heat treatment at 400 ° C. to 700 ° C. and crushing,
The mixing ratio of the bismuth oxide powder to the chromium oxide powder is 1 mol part or more of the chromium oxide powder to 1 mol part of the bismuth oxide powder in a molar ratio, in the state where Bi ₂ O ₃ is more than Cr ₂ O _3. Although it is possible to avoid the generation of harmful hexavalent chromium that tends to occur in the synthesis, the preferable molar ratio of both bismuth oxide and chromium oxide is 25:75 to 50:50.
It is.

When the zinc oxide porcelain composition of the present invention as described above is sintered, it is preferable to press-mold it into a predetermined shape and fire the molded body at about 750 to 1100 ° C. By firing at a temperature within this range, it becomes possible to manufacture a zinc oxide varistor having excellent electrical characteristics such as non-linear resistance characteristics and reliability with a high yield.

[0072]

【Example】

(Example 1) A powder of bismuth oxide (Bi ₂ O ₃ ) and a powder of antimony oxide (Sb ₂ O ₃ ) (the particle size of each powder is about 2 to 3 μm) in a weight ratio of 98: 2. Mixed so that This mixed powder is heated at 600 ° C. in the atmosphere for 5
After heat treatment for a period of time, the stabilized zirconia was finely pulverized with a ball mill of a monomaron pot using cobblestone to obtain a synthetic powder (particle size: about 0.5 to 1.5 μm).
Hereinafter, bismuth oxide, antimony oxide and the synthetic powder thus prepared are referred to as bismuth oxide / antimony oxide synthetic powder.

Zinc oxide (ZnO) powder (average particle size 0.3
μm), the bismuth oxide / antimony oxide synthetic powder, and cobalt oxide (CoO) powder (particle size of about 0.5 to 1.
5 μm) and manganese dioxide (MnO ₂ ) powder (particle size of about 2 to 3 μm) while changing the amount of the bismuth oxide / antimony oxide synthetic powder, the weight ratio is 100: 0.2 to 2
The powder blended so as to be 5.0: 0.954: 0.414 was mixed and pulverized by a wet method for 12 to 18 hours using a monomaron pot and a stabilized zirconia ball, and pulverized so as to pass through a 325 mesh. did. The obtained blended powder was dried and pressed into a disk shape. Then, the obtained molded body is heated in the atmosphere at a heating rate of 50 ° C./hour to
After holding at 75 ° C. for 13 hours, the temperature was lowered at a temperature lowering rate of 50 ° C./hour to obtain a sintered body. The sample size of the sintered body is 1.
The diameter was 2 mm and the diameter was 14 mm.

Next, a method for manufacturing a zinc oxide varistor will be described with reference to FIG. FIG. 1 is a schematic perspective view of a zinc oxide varistor formed by using the zinc oxide ceramic 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 layers formed on both surfaces. Electrode 12 by
Was formed. After the lead wire 13 was attached to the electrode 12 with solder, a molded product other than the lead wire was coated with an epoxy resin to obtain a zinc oxide varistor.

Zinc oxide varistor thus obtained
Was evaluated for electrical characteristics. Start up as initial electrical characteristics
Overvoltage V_{1mA / mm}(Between both terminals when a current of 1 mA is applied
Voltage for 1mm thickness) and non-linear resistance index
_0.1mAα_1mA(V_1mAAnd V_0.1mAValue obtained by using
(Note that in all tables below, non-linear resistance index
_{0. 1mA}α_1mATo simplify_0.1α_1mAWas displayed. Also,
In the text below, this is simply referred to as the α value. ). Non
The greater the linear resistance index, the greater the surge absorption capacity.
You. Moreover, the reliability with respect to a DC load was evaluated. 80 ° C
DC wattage of 0.2 watt for 500 hours in high temperature atmosphere
Applied, varistor rising voltage V_1mA Rate of change ΔV
_1mA/ V_1mA(DC load change rate) was measured. Barista standing
Lift voltage V _1mA Rate of change ΔV_1mA/ V_1mAIs small
Thorough electrical characteristics of zinc oxide varistor are stable and reliable
It shows that the sex is good. In addition, confidence in surge
Reliability was evaluated. 8 × 20μsec, 0.5kA pulse
Rising voltage V of varistor by applying twice_1mAchange of
Rate (surge change rate) ΔV_1mA/ V_1mA I asked. Table 1
Table 2 shows the composition of the sample, and Table 2 shows the evaluation results of the electrical characteristics. Sir
Electrical characteristics of zinc oxide varistors with smaller di-change rate
Is stable and reliable. What
The numerical value showing the evaluation result of electrical characteristics is the smallest in the lot.
The value and maximum value are shown. Therefore, the minimum and maximum
The smaller the large difference, the smaller the variation in quality within the lot.
It shows a bad thing.

[0076]

[Table 1]

[0077]

[Table 2]

As can be seen from Tables 1 and 2, the zinc oxide varistor using the zinc oxide porcelain of the present example is a 0.2 parts by weight sample (Sample No.) having a low amount of bismuth oxide / antimony oxide synthetic powder. Except for # 101), the rising voltage V _{1mA / mm} is high, and the change rate of the rising voltage V _1mA is ΔV _{1 mA} even for long-term DC load and surge.
The absolute value of / V _1mA was 5% or less, and the reliability was excellent.
Further, as shown in Table 2, there was little variation in the electrical characteristics within the lot.

Although not shown in Table 2, when a zinc oxide varistor was prepared from the ceramic composition of this example, the variation in electrical characteristics between lots was as small as the variation within lots. Specifically, the process capability index (one of the indices that shows the variation of products at the production plant) is ± ₁ V with a standard width of ± _{1 mA} .
7%, using the conventional composition without heat treatment, 1200 ℃
In the sample fired at a high temperature of 1.0, 1.0 was 1.3.
It became 33. As a result, the yield was 90% in the sample using the conventional composition without heat treatment, whereas it was 95% in this example, which was a remarkable improvement. In addition, Bi ₂ O ₃ /
If the amount of Sb ₂ O ₃ synthetic powder added exceeds 20 parts by weight, a plurality of compacts are stacked and fired at the time of firing. In addition to lack of mass productivity, the samples adhered to each other, so that the electrical characteristics could not be measured (sample number # 109). Therefore, the addition amount of the synthetic powder is preferably 0.5 to 20 parts by weight with respect to 100 parts by weight of ZnO powder.

(Comparative Example 1) A conventional porcelain composition in which a mixture of bismuth oxide powder and antimony oxide powder was not preliminarily heat-treated into a synthetic powder, and three kinds of sintered bodies having the same composition as in Example 1 were used. A zinc oxide varistor was produced.

The weight ratio of zinc oxide powder, bismuth oxide powder, antimony oxide powder, cobalt oxide powder and manganese dioxide powder was 100: 0.98: 0.02 :.
0.954: 0.414 (# 114), 100: 1.9
6: 0.04: 0.954: 0.414 (# 115),
And 100: 4.9: 0.1: 0.954: 0.414.
(# 116), and each of these powders was wet-mixed for 18 hours in a Monomeron pot using stabilized zirconia balls, and pulverized. Then, in the same manner as in Example 1, a sintered body having a thickness of 1.2 mm and a diameter of 14 mm was obtained, a zinc oxide varistor was produced, and the electrical characteristics of the zinc oxide varistor were evaluated. Table 3 shows the sample composition, and Table 4 shows the evaluation results of the electrical characteristics.

[0082]

[Table 3]

[0083]

[Table 4]

As can be seen from Tables 3 and 4, the zinc oxide varistor made of the conventional porcelain composition had a significantly reduced V _1mA after a DC load of 0.2 watts, and the DC load change rate ΔV _1mA. The absolute value of / V _1mA was 10% or more. Also, the absolute value of the surge change rate exceeded 10%, and the reliability was extremely low. Further, as shown in Table 4, there was a large variation within the lot.

Although not shown in Table 4, the variation between lots in the electrical characteristics of the zinc oxide varistor of the comparative example was larger than the variation within the lot. There were many varistor whose V _{1 mA / mm} and α value (non-linear resistance index) were lower than those shown in Table 4. That is, it can be seen that the sintering temperature of 975 ° C. is too low by the conventional method, and thus is unsuitable for the production of zinc oxide varistor.

As is clear from Example 1 and Comparative Example 1,
The zinc oxide varistor using the low temperature sintered body of this example is superior to the conventional zinc oxide varistor in terms of initial electrical characteristics, reliability, and variations in electrical characteristics within and between lots.

Example 2 Bismuth oxide powder (particle size: about 2 to 3 μm) and antimony oxide powder (particle size: about 2 to 3 μm)
m) is mixed in a weight ratio of 60:40, heat-treated in an air atmosphere at 675 ° C. for 15 minutes, and finely pulverized in a monomeron pot for 18 hours by wet milling using stabilized zirconia balls. Thus, Bi ₂ O ₃ / Sb ₂ O ₃ synthetic powder (particle size of about 2 to 3 μm) consisting of (bismuth oxide / antimony oxide) was obtained.

Zinc oxide powder (average particle size 0.3 μm), Bi ₂ O ₃ / Sb ₂ O ₃ synthetic powder, cobalt oxide powder (particle size about 0.5 to 1.5 μm) and manganese dioxide powder (particle size). About 2-3 μm) and the weight ratio is 100: 3.5: 0.8
The powder blended so as to be 0: 0.40 was wet-mixed and pulverized for 18 hours in a Monomeron pot using stabilized zirconia balls. The powder obtained is dried and converted to Al ₂ O _{3 based} on 100 parts by weight of the zinc oxide to give 0.0013.
Aluminum nitrate containing a part by weight of aluminum oxide was added in the form of an aqueous solution to prepare a blended powder, which was then pressure-molded into a disc shape. The obtained molded body was heated in the atmosphere at a heating rate of 150 ° C./hour to 800 ° C., 850 ° C., 9 ° C.
00 ° C, 950 ° C, 1000 ° C, 1050 ° C, 1100
After holding at each temperature of 15 ℃ for 15 hours, the temperature decrease rate is 150 ℃ /
The temperature was lowered over time to obtain a sintered body. The sample size of the sintered body was 1.2 mm in thickness and 14 mm in diameter.

A zinc oxide varistor was manufactured in the same manner as in Example 1 below. Further, in the same manner as in Example 1, the electrical characteristics of the obtained zinc oxide varistor were evaluated. Table 5 shows the sample composition, and Table 6 shows the evaluation results of the electrical characteristics.

[0090]

[Table 5]

[0091]

[Table 6]

As can be seen from Tables 5 and 6, 800-
As a result of firing over a temperature range of 1100 ° C., the zinc oxide varistor manufactured by the porcelain composition of this example has a high rising voltage, and even if it is subjected to a long-term DC load or surge, the rising voltage is high. V _1mA change rate △ V
The absolute value of _1mA / V _1mA was 5% or less, and the reliability was excellent. Further, as shown in Table 6, there was little variation in the electrical characteristics within the lot.

Although not shown in Table 6, when a zinc oxide varistor was made from the porcelain composition of this example, the variation in the electrical characteristics between lots was as small as the variation within the lot. Specifically, in the conventional method, the process capability index is
When the standard width was ± ₁ % at V _{1 mA} , the value of 1.0 was 1.33 for the sample using the conventional composition without heat treatment. As a result, the yield was 90% in the sample using the conventional composition without heat treatment, whereas it was 95% in this example, which was a remarkable improvement.

Example 3 Bismuth oxide powder (particle size: about 2 to 3 μm) and antimony oxide fine powder (particle size: about 2 to 3)
μm) was mixed in a weight ratio as shown in the section of synthetic powder in Table 7. Heat treatment was performed at 475 ° C. in an air atmosphere for 5 hours to obtain 10 kinds of (bismuth oxide / antimony oxide) synthetic powder (particle size: about 2 to 3 μm).

Zinc oxide powder (average particle size 0.3 μm), the above-mentioned (bismuth oxide / antimony oxide synthetic powder), cobalt oxide powder (particle size about 0.5 to 1.5 μm) and manganese dioxide powder (particle size about 0.5 μm). 2 to 3 μm) were blended as shown in the weight ratio in Table 7, and were mixed and pulverized by a wet process in a Monomeron pot for 18 hours using a stabilized zirconia ball. The obtained powder was dried, and aluminum nitrate containing 0.0013 parts by weight of aluminum oxide in terms of Al ₂ O _{3 based} on 100 parts by weight of zinc oxide was added in the form of an aqueous solution to a disk. It was molded into a shape. The obtained molded body was heated in the atmosphere at a temperature rising rate of 100 ° C./hour, held at 1050 ° C. for 20 minutes, and then cooled at a temperature lowering rate of 100 ° C./hour to obtain a sintered body. The sample size of the sintered body is 1.2 mm thick,
The diameter was 14 mm.

A zinc oxide varistor was manufactured in the same manner as in Example 1 below. Further, in the same manner as in Example 1, the electrical characteristics of the obtained zinc oxide varistor were evaluated. Table 7 shows the sample composition, and Table 8 shows the evaluation results of the electrical characteristics.

[0097]

[Table 7]

[0098]

[Table 8]

From Tables 7 and 8, the zinc oxide varistor using the porcelain composition of this example was added with Bi ₂ O ₃ / S.
When the amount of bismuth oxide in the b ₂ O ₃ synthetic powder is 0.5% by weight or more with respect to zinc oxide 100, the α value is large, and even for long-term DC load and surge, Change rate of rising voltage V _1mA ΔV _1mA / V _1mA absolute value is 5
% Or less, and the reliability was excellent.

When the amount of the synthetic powder of bismuth oxide and antimony oxide added was more than 20 parts by weight with respect to 100 parts by weight of zinc oxide (Sample No. # 304), a plurality of compacts were stacked during firing. In the case of firing by calcination, the varistor lacks mass productivity because the sintered bodies are fused together. Further, the amount of antimony oxide in the added bismuth oxide / antimony oxide synthetic powder was 0.01 to 10 with respect to zinc oxide 100 by weight ratio, and good electrical characteristics were exhibited. Further, in Table 310, the addition amount of the synthetic powder of bismuth oxide and antimony oxide is considerably larger than 20 parts by weight with respect to 100 parts by weight of zinc oxide, so that the rising voltage V _1mA and the variation in α value are large. At the same time, the rate of change with respect to a DC load or surge increases, which is not preferable.

Example 4 Powder of bismuth oxide (Bi ₂ O ₃ ) and powder of antimony oxide (Sb ₂ O ₃ ) (particle size of each powder is about 2 to 3 μm), and boron oxide ( B ₂ O ₃ ) (particle size of about 2 to 3 μm) in a weight ratio of 97.5:
It mixed so that it might become 2.0: 0.5. This mixed powder was subjected to a heat treatment at 450 ° C. for 1 hour in an air atmosphere, and then finely pulverized with a ball mill of a monomaron pot using stabilized zirconia as a cobblestone to obtain a synthetic powder (particle size: about 0.
5 to 1.5 μm) was obtained. Hereinafter, the synthetic powder thus prepared from bismuth oxide, antimony oxide and boron oxide is referred to as bismuth oxide / antimony oxide / boron oxide synthetic powder.

Zinc oxide (ZnO) powder (average particle size 0.3
μm), the bismuth oxide / antimony oxide / boron oxide synthetic powder, cobalt oxide (CoO) powder (particle size of about 0.5 to 1.5 μm), and manganese dioxide (MnO ₂ ).
The weight ratio of the powder (particle size: about 2 to 3 μm) was changed from 100: 0.2 to 20.0: 0.954: 0.41 while changing the amount of the bismuth oxide / antimony oxide / boron oxide synthetic powder.
The powder compounded so as to be 4 was mixed and pulverized by a wet method for 12 to 18 hours using a monomaron pot and a stabilized zirconia ball, and pulverized so as to pass through 325 mesh. The obtained blended powder was dried and pressed into a disk shape. Then, the obtained molded body was heated in the atmosphere at a temperature rising rate of 50 ° C./hour, held at 950 ° C. for 13 hours, and then cooled at a temperature lowering rate of 50 ° C./hour to obtain a sintered body. The sample size of the sintered body was 1.2 mm in thickness and 14 mm in diameter.

A zinc oxide varistor was manufactured in the same manner as in Example 1 below. Further, in the same manner as in Example 1, the electrical characteristics of the obtained zinc oxide varistor were evaluated. Table 9 shows the sample composition, and Table 10 shows the evaluation results of the electrical characteristics.

[0104]

[Table 9]

[0105]

[Table 10]

As can be seen from (Table 9) and (Table 10),
Manufactured by the method for manufacturing a zinc oxide varistor according to the present invention
Zinc oxide varistors are bismuth oxide / antimony oxide /
Low amount of boron oxide synthetic powder 0.2wt part (Sample No. # 40
Except for 1), the rising voltage is high and the DC load is long.
The rising voltage V
_1mARate of change ΔV_1mA/ V_1mAIf the absolute value of is less than 5%,
It was very reliable. In addition, as shown in (Table 10),
The variation in electrical characteristics within the lot was also small. (Table 1
Although not shown in 0), zinc oxide burr is produced by this manufacturing method.
Creating a raster also reduces variations in electrical characteristics between lots.
It was as small as the variation within the unit. As a result of the above, the product
Yield was significantly improved. Note that Bi₂O_Three-Sb₂O_ThreeSynthetic powder
If the amount of powder added exceeds 20 wt parts, the samples will stick together and be measured.
Could not be determined (see sample number # 409).

(Comparative Example 2) A conventional manufacturing method was applied to Example 1
Three kinds of zinc oxide varistor using the sintered body having the same composition as the above were manufactured.

Zinc oxide powder (ZnO), bismuth oxide powder (Bi ₂ O ₃ ), antimony oxide powder (Sb ₂ O ₃ ), boron oxide powder (B ₂ O ₃ ), cobalt oxide powder (CoO) and manganese dioxide powder. (MnO ₂ ) in a weight ratio of 100: 0.975: 0.02:
0.005: 0.954: 0.414 (# 414) and 100: 1.95:
0.04: 0.01: 0.954: 0.414 (# 415) and 100: 4.8
75: 0.1: 0.025: 0.954: 0.414 (# 416) were blended, and these powders were mixed by a wet method and ground.
The obtained mixed powder was dried and molded into a disc shape. These compacts were heated in an air atmosphere at a heating rate of 50 ° C./hour, held at 950 ° C. for 13 hours, and then cooled at a cooling rate of 50 ° C./hour to obtain sintered bodies. The sample size of the sintered body is thickness 1.
The diameter was 2 mm and the diameter was 14 mm.

Thereafter, a zinc oxide varistor was manufactured in the same manner as in Example 1. Further, in the same manner as in Example 1, the electrical characteristics of the obtained zinc oxide varistor were evaluated. Table 11 shows the sample composition, and Table 12 shows the evaluation results of the electrical characteristics.

[0110]

[Table 11]

[0111]

[Table 12]

As can be seen from (Table 11) and (Table 12), the zinc oxide varistor manufactured by the conventional manufacturing method is
V _1mA after a DC load of 0.2 watts was remarkably reduced, and the absolute value of the DC load change rate ΔV _1mA / V _1mA was 10% or more. Moreover, the absolute value of the surge change rate also greatly exceeded 10%, and the reliability was extremely low. Further, as shown in (Table 12), there was a large variation within the lot.

Although not shown in Table 12, the variation between lots in the electrical characteristics of the zinc oxide varistor manufactured by the conventional method was much larger than the variation within the lot. In other words, the sintering temperature of 950 ° C is too low by the conventional method, and it is therefore unsuitable for the production of zinc oxide varistors. Even if the conventional method is used, a varistor having considerably good characteristics can be obtained by firing at a high temperature, for example, 1250 ° C. However, as mentioned above, when the sintering temperature is high, it is necessary to use a more heat-resistant material for the electric furnace heater, furnace wall material, container, etc. used for sintering, or to use a heater that can heat at a higher temperature. However, there is a problem that the equipment cost is high and the production cost is high together with the power cost. Further, in such high temperature sintering, about half or more of the added bismuth oxide is vaporized during firing and corrodes and destroys the furnace wall material, container, and the like. In addition, when a large amount is fired, there is a problem that the quality of the product tends to vary due to the evaporation amount of bismuth oxide. Therefore,
It is preferable to use a composition that can be sintered at a low temperature as in the present invention.

As described above, as is clear from the comparison between Example 4 and Comparative Example 2, the zinc oxide varistor manufactured by the low temperature sintering manufacturing method of the present invention has initial electrical characteristics, reliability, and lot and lot characteristics. Any variation in electrical characteristics between them is superior to the zinc oxide varistor manufactured by the conventional manufacturing method.

Example 5 Bismuth oxide powder (particle size: about 2 to 3 μm) and antimony oxide powder (particle size: about 2 to 3 μm)
m) was mixed at a weight ratio of 85:15, and heat-treated at 550 ° C. for 5 hours in an air atmosphere. on the other hand,
Separately, powder of bismuth oxide (particle size of about 2-3 μ
m) and fine powder of boron oxide (particle size of about 2 to 3 μm) were mixed at a weight ratio of 93: 7, and this mixture was subjected to heat treatment at 600 ° C. for 10 minutes in an air atmosphere. These two
Powder in a ratio of 10: 1 by weight, and by using a stabilized zirconia ball and finely pulverizing it in a monomaron pot for 18 hours by wet milling, a synthetic powder of (bismuth oxide / antimony oxide / boron oxide) (grains) A diameter of about 2-3 μm) was obtained.

Zinc oxide powder (average particle size 0.3 μm), Bi ₂ O ₃ / Sb ₂ O ₃ / B ₂ O ₃ synthetic powder, cobalt oxide powder (particle size about 0.5 to 1.5 μm) and dioxide. The manganese powder (particle size: about 2 to 3 μm) was used in a weight ratio of 100: 3.
The powder blended so as to have a ratio of 3: 0.80: 0.40 was used in a monomeron pot using stabilized zirconia balls.
It was mixed and crushed by wet for an hour. The obtained powder was dried, and aluminum nitrate containing 0.0013 parts by weight of aluminum oxide in terms of Al ₂ O ₃ was added in the form of an aqueous solution to 100 parts by weight of zinc oxide to prepare a blended powder. Then, it was pressed into a disk shape. The obtained molded body was heated in the atmosphere at a heating rate of 50 ° C./hour to 750 ° C.,
800 ° C, 900 ° C, 1000 ° C, 1050 ° C, 110
After holding at each temperature of 0 ℃ for 15 hours, the cooling rate is 50 ℃ /
The temperature was lowered over time to obtain a sintered body. The sample size of the sintered body was 1.2 mm in thickness and 14 mm in diameter.

A zinc oxide varistor was manufactured in the same manner as in Example 1 below. Further, in the same manner as in Example 1, the electrical characteristics of the obtained zinc oxide varistor were evaluated. Table 13 shows the sample composition, and Table 14 shows the evaluation results of the electrical characteristics.

[0118]

[Table 13]

[0119]

[Table 14]

As can be seen from Tables 13 and 14, 75
As a result of firing over a temperature range of 0 to 1100 ° C., the zinc oxide varistor produced by the porcelain composition of this example has a high rising voltage, and is resistant to a long-term DC load and surge. Change rate of rising voltage V _1mA △
The absolute value of V _1mA / V _1mA was 5% or less, and the reliability was excellent. Further, as shown in Table 6, there was little variation in the electrical characteristics within the lot.

Although not shown in Table 14, when a zinc oxide varistor was made with the ceramic composition of this example, the variation in the electrical characteristics between lots was as small as the variation within the lot. Specifically, the process capability index has a standard width of V _1mA.
Was ± 5%, and 1.0 was 1.33 in the sample using the conventional composition without heat treatment. As a result, the yield of the product was 90% in the sample using the conventional composition without heat treatment, whereas it was 95% in this example.
And markedly improved.

Example 6 Bismuth oxide powder (particle size: about 2 to 3 μm) and antimony oxide fine powder (particle size: about 2 to 3)
μm) was mixed in a weight ratio of 70:30 and heat-treated at 500 ° C. for 30 hours in an air atmosphere. On the other hand, separately from this, powder of bismuth oxide (particle size of about 2-3
μm) and boron oxide fine powder (particle size: about 2 to 3 μm) were mixed, and heat treatment was performed at 450 ° C. for 1 hour in an air atmosphere. Next, these two are weight ratio 97.5: 2.5, 95.0: 5.0, 9
2.5: 7.5, 90.0: 10.0, 87.5: 12.5, 85.0: 15.0, 82.5: 1
Blended in the ratio of 7.5, 80.0: 20.0 and mixed by wet using a stabilized zirconia ball in a Monomaron pot for 18 hours.
By finely pulverizing, eight kinds of (bismuth oxide / antimony oxide / boron oxide) synthetic powders were obtained. In addition,
If the heat treatment temperature becomes high, the pulverization becomes difficult, so the heat treatment temperature must be 700 ° C. or lower.

Zinc oxide powder (average particle size 0.3 μm), the above-mentioned (bismuth oxide / antimony oxide / boron oxide) synthetic powder, cobalt oxide powder (particle size about 0.5 to 1.5 μm).
m) and manganese dioxide powder (particle size of about 2-3 μm),
The mixture was blended so that the weight ratio was 100: 4.0: 0.50: 0.50, and the mixture was wet-mixed and pulverized for 18 hours in a Monomeron pot using stabilized zirconia balls. The obtained powder is dried, and A is added to 100 parts by weight of the zinc oxide.
After adding aluminum nitrate containing 0.0013 parts by weight of aluminum oxide in terms of l ₂ O ₃ in the form of an aqueous solution,
It was formed into a disk shape. The obtained molded body is heated at a heating rate of 150 ° C./hour in an air atmosphere and heated at 1000 ° C. for 2 hours.
After holding for a time, the temperature was decreased at a temperature decrease rate of 150 ° C./hour to obtain a sintered body. The sample size of the sintered body was 1.2 mm in thickness and 14 mm in diameter.

A zinc oxide varistor was manufactured in the same manner as in Example 1 below. Further, in the same manner as in Example 1, the electrical characteristics of the obtained zinc oxide varistor were evaluated. Table 15 shows the sample composition, and Table 16 shows the evaluation results of the electrical characteristics.

[0125]

[Table 15]

[0126]

[Table 16]

From Tables 15 and 16, the zinc oxide varistor using the porcelain composition of this example has α
Large value, even for long-term DC load and surge,
The absolute value of the change rate ΔV _1mA / V _1mA of the rising voltage V _1mA was 5% or less, and the reliability was excellent.

The values in parentheses in the list of synthetic powders in Table 15 indicate the weight ratio of the bismuth oxide / antimony oxide synthetic powder and the bismuth oxide / boron oxide synthetic powder. (Example 7) Bismuth oxide (Bi ₂ O ₃ ) powder, antimony oxide (Sb ₂ O ₃ ) powder (the particle size of each powder is about 2 to 3 μm), and chromium oxide (Cr ₂ O 3). ₃ )
(Particle size of about 0.5 to 1.5 μm) in weight ratio of 97: 2: 1
Were mixed so that This mixed powder is placed in an atmosphere of 6
After heat treatment at 00 ° C. for 30 minutes, fine powder is pulverized with a ball mill of a monomaron pot using stabilized zirconia as a cobblestone to obtain a synthetic powder (particle size: about 0.5 to 1.5 μm).
m) was obtained. Hereinafter, the synthetic powder thus prepared from bismuth oxide, antimony oxide and chromium oxide is referred to as bismuth oxide / antimony oxide / chromium oxide synthetic powder.

Zinc oxide (ZnO) powder (average particle size 0.3
μm), the bismuth oxide / antimony oxide / chromium oxide synthetic powder, cobalt oxide (CoO) powder (particle size of about 0.5 to 1.5 μm), and manganese dioxide (MnO ₂ ).
The weight ratio of the powder (particle size: about 2 to 3 μm) was changed from 100: 0.2 to 25.0: 0.954: 0.4 while changing the amount of the bismuth oxide / antimony oxide / chromium oxide synthetic powder.
The powder blended so as to be 14 was mixed and pulverized by a wet method for 18 hours using a monomaron pot and a stabilized zirconia ball, and pulverized so as to pass through a 325 mesh. The obtained blended powder was dried and pressed into a disk shape.
Then, the obtained molded body is heated in the atmosphere at a heating rate of 50 ° C.
The temperature was raised at a heating rate of 1 hour / hour, the temperature was held at 900 ° C. for 11 hours, and then the temperature was lowered at a rate of 50 ° C./hour to obtain a sintered body. The sample size of the sintered body was 1.2 mm in thickness and 14 mm in diameter.

Table 17 shows the composition of the sample, and Table 18 shows the evaluation results of the electrical characteristics. The numerical values showing the evaluation results of the electrical characteristics indicate the minimum value and the maximum value within the lot.

[0131]

[Table 17]

[0132]

[Table 18]

As can be seen from (Table 17) and (Table 18)
Manufactured by the method for manufacturing a zinc oxide varistor according to the present invention.
Zinc oxide varistors are bismuth oxide / antimony oxide.
The amount of nickel / chromium oxide synthetic powder was as low as 0.2 wt parts (test
Good initial characteristics, except for the charge number # 701), and long-term DC load
The rising voltage V
_1mARate of change ΔV_1mA/ V_1mAIf the absolute value of is less than 5%,
It was very reliable. In addition, as shown in (Table 18),
The variation in electrical characteristics within the lot was also small.

Although not shown in Table 18, when the zinc oxide varistor was prepared by this manufacturing method, the variation in the electrical characteristics between lots was as small as the variation within the lot. As a result of the above, the yield of products was significantly improved. When the amount of Bi ₂ O ₃ —Sb ₂ O ₃ synthetic powder added exceeded 20 wt parts, a plurality of samples were stacked and sintered, so that the sintered bodies could not be measured for sticking (sample number # 709).

(Comparative Example 3) In a conventional manufacturing method, Example 7 was used.
Three kinds of zinc oxide varistor using the sintered body having the same composition as the above were manufactured.

Zinc oxide powder (ZnO), bismuth oxide powder (Bi ₂ O ₃ ), antimony oxide powder (Sb ₂ O ₃ ), chromium oxide powder (Cr ₂ O ₃ ), cobalt oxide powder (CoO) and manganese dioxide powder. (MnO ₂ ) in a weight ratio of 100: 0.97: 0.02
: 0.01: 0.954: 0.414 (# 714) and 100: 1.94:
0.04: 0.02: 0.954: 0.414 (# 715) and 100:
4.85: 0.1: 0.05: 0.954: 0.414 (# 716) were mixed, and these powders were mixed by a wet method and pulverized.
The obtained mixed powder was dried and molded into a disc shape. These compacts were heated in an air atmosphere at a heating rate of 50 ° C./hour, held at 900 ° C. for 13 hours, and then cooled at a cooling rate of 50 ° C./hour to obtain sintered bodies. The sample size of the sintered body is thickness 1.
The diameter was 2 mm and the diameter was 14 mm.

A zinc oxide varistor was manufactured in the same manner as in Example 1 below. Further, in the same manner as in Example 1, the electrical characteristics of the obtained zinc oxide varistor were evaluated. Table 19 shows the sample composition, and Table 20 shows the evaluation results of the electrical characteristics.

[0138]

[Table 19]

[0139]

[Table 20]

As can be seen from (Table 19) and (Table 20), the zinc oxide varistor manufactured by the conventional manufacturing method is
V _1mA after a DC load of 0.2 watts was remarkably reduced, and the absolute value of the DC load change rate ΔV _1mA / V _1mA was 10% or more. Also, the absolute value of the surge change rate exceeded 10%, and the reliability was extremely low. Further, as shown in (Table 20), there was a large variation within the lot.

Although not shown in Table 20, the variation between lots in the electrical characteristics of the zinc oxide varistor manufactured by the conventional method was much larger than the variation within the lot. There were many varistor whose V1mA / mm and α value were lower than those shown in (Table 20).

That is, it can be seen that the sintering temperature of 900 ° C. is too low by the conventional method, so that it is not suitable for the production of zinc oxide varistor. Even if the conventional method is used,
Firing at high temperatures, for example 1250 ° C, gives varistors with fairly good properties. However, in the case where a good quality sintered body cannot be obtained unless the sintering temperature is raised as described above, there are various disadvantages as described above.

As described above, as is clear from the comparison between Example 7 and Comparative Example 3, the zinc oxide varistor manufactured by the low temperature sintering manufacturing method according to the present invention has initial electrical characteristics, reliability, and lot and lot characteristics. Any variation in electrical characteristics between them is superior to the zinc oxide varistor manufactured by the conventional manufacturing method.

Example 8 Bismuth oxide powder (particle size: about 2 to 3 μm) and antimony oxide powder (particle size: about 2 to 3 μm)
m) was mixed at a weight ratio of 85:15, and heat-treated at 550 ° C. for 5 hours in an air atmosphere. on the other hand,
Separately, powder of bismuth oxide (particle size of about 2-3 μ
m) and fine powder of chromium oxide (particle size: about 0.5 to 1.5μ)
m) was mixed at a weight ratio of 75:25, and this mixture was subjected to heat treatment at 550 ° C. for 5 hours in an air atmosphere. These two are mixed in a weight ratio of 10.0: 1.0, and wet pulverized for 18 hours in a monomaron pot using stabilized zirconia balls to obtain (bismuth oxide / antimony oxide / chromium oxide). ) Synthetic powder (particle size of about 2 to 3 μm) was obtained.

Zinc oxide powder (average particle size 0.3 μm), Bi ₂ O ₃ / Sb ₂ O ₃ / Cr ₂ O ₃ synthetic powder, cobalt oxide powder (particle size about 0.5 to 1.5 μm) and dioxide. Manganese powder (200 mesh), weight ratio 100:
The powder blended so as to be 3.3: 0.80: 0.40 was wet-mixed and pulverized for 18 hours in a Monomeron pot using stabilized zirconia balls. The obtained powder was dried, and aluminum nitrate containing 0.0013 parts by weight of aluminum oxide in terms of Al ₂ O ₃ was added in the form of an aqueous solution to 100 parts by weight of zinc oxide to prepare a blended powder. Then, it was pressed into a disk shape. The obtained molded body is heated in the air at a temperature rising rate of 150 ° C./hour to 800
℃, 850 ℃, 900 ℃, 1000 ℃, 1050 ℃, 1
Hold at each temperature of 100 ℃ for 15 hours, then cool down at a rate of 15
The temperature was lowered at 0 ° C./hour to obtain a sintered body. The sample size of the sintered body was 1.2 mm in thickness and 14 mm in diameter.

A zinc oxide varistor was manufactured in the same manner as in Example 1 below. Further, in the same manner as in Example 1, the electrical characteristics of the obtained zinc oxide varistor were evaluated. Table 21 shows the sample composition, and Table 22 shows the evaluation results of the electrical characteristics.

[0147]

[Table 21]

[0148]

[Table 22]

As can be seen from (Table 21) and (Table 22), as a result of firing in the temperature range of 800-1100 ° C., the zinc oxide varistor manufactured by the method for manufacturing a zinc oxide varistor according to the present invention has a long life. Change rate ΔV of rising voltage V _1mA both for DC load and surge
The absolute value of _1mA / V _1mA was 5% or less, and the reliability was excellent. In addition, as shown in (Table 22), there was little variation in the electrical characteristics within the lot.

Although not shown in Table 22, when the zinc oxide varistor was prepared by this manufacturing method, the variation in the electrical characteristics between lots was as small as the variation within the lot. As a result of the above, the yield of products was significantly improved.

Example 9 Bismuth oxide powder (particle size: about 2 to 3 μm) and antimony oxide fine powder (particle size: about 2 to 3)
μm) was mixed in a weight ratio of 70:30 and heat-treated at 500 ° C. for 30 minutes in an air atmosphere. On the other hand, separately from this, powder of bismuth oxide (particle size of about 2 to 3
μm) and a fine powder of chromium oxide (particle size: about 2 to 3 μm) were mixed at a molar ratio of 60:40, and this mixture was subjected to heat treatment at 600 ° C. for 2 hours in an air atmosphere.

The weight ratio of these two is 97.5: 2.5, 95.0.
: 5.0, 92.5: 7.5, 90.0: 10.0, 87.5: 12.5, 8
By mixing in a ratio of 5.0: 15.0, 82.5: 17.5, 80.0: 20.0 and finely pulverizing, eight kinds of bismuth oxide / antimony oxide / chromium oxide synthetic powders were obtained.

The weight ratio of the zinc oxide powder, the bismuth oxide / antimony oxide / chromium oxide synthetic powder, the cobalt oxide powder and the manganese dioxide powder was 100: 4.0: 0.50:
The ingredients were blended so as to be 0.50, mixed by a wet method and pulverized. The obtained powder is dried, and aluminum nitrate containing an aluminum oxide content of 0.0013 in terms of Al ₂ O ₃ with respect to 100 parts of zinc oxide is added to the powder in the form of an aqueous solution, followed by pressure molding and pulverization. Then, it was formed into a disk shape. The obtained molded body is heated in the atmosphere at a heating rate of 50 ° C./hour and heated at 950 ° C.
After holding for 12 hours, the temperature was lowered at a temperature lowering rate of 50 ° C./hour to obtain a sintered body. The sample size of the sintered body is 1.2 mm thick and the diameter is 14
It was mm.

A zinc oxide varistor was manufactured in the same manner as in Example 1 below. Further, in the same manner as in Example 1, the electrical characteristics of the obtained zinc oxide varistor were evaluated. Table 23 shows the sample composition, and Table 24 shows the evaluation results of the electrical characteristics.

[0155]

[Table 23]

[0156]

[Table 24]

From (Table 23) and (Table 24), the zinc oxide varistor manufactured by the method for manufacturing a zinc oxide varistor according to the present invention has a large α value, and has a large DC value and a long-term DC load and surge. However, the absolute value of the change rate ΔV _1mA / V _1mA of the rising voltage V _1mA was 5% or less, which was excellent in reliability.

The numerical values in parentheses in the list of synthetic powders (Table 23) indicate the weight ratio between the bismuth oxide / antimony oxide synthetic powder and the bismuth oxide / chromium oxide synthetic powder. (Example 10) Bismuth oxide (Bi ₂ O ₃ ) powder, antimony oxide (Sb ₂ O ₃ ) powder (each powder has a particle size of about 2 to 3 μm), and chromium oxide powder (Cr ₂
O ₃ ) (particle size: about 0.5 to 1.5 μm) and boron oxide powder (B ₂ O ₃ ) (particle size: about 2 to 3 μm) in a weight ratio of 96.5:
Mixed to be 2: 1: 0.5. This mixed powder was subjected to heat treatment at 500 ° C. for 30 minutes in an air atmosphere, and then finely pulverized with a ball mill of a monomaron pot using stabilized zirconia as a cobblestone to obtain a synthetic powder (particle size: about 0.
5 to 1.5 μm) was obtained. Hereinafter, the synthetic powder thus prepared from bismuth oxide, antimony oxide, chromium oxide and boron oxide is referred to as bismuth oxide / antimony oxide / chromium oxide / boron oxide synthetic powder.

Zinc oxide (ZnO) powder (average particle size 0.3
μm), the bismuth oxide / antimony oxide / chromium oxide / boron oxide synthetic powder, and cobalt oxide (CoO)
Powder (particle size: about 0.5 to 1.5 μm) and manganese dioxide (MnO ₂ ) powder (particle size: about 2 to 3 μm) were used in different amounts of bismuth oxide / antimony oxide / chromium oxide / boron oxide synthetic powder. However, the weight ratio is 100: 0.2 to 25.
The powder blended so as to be 0: 0.954: 0.414 was mixed and pulverized for 12 to 18 hours using a monomaron pot and a stabilized zirconia ball, and pulverized so as to pass through a 325 mesh.

A zinc oxide varistor was manufactured in the same manner as in Example 1 below. Further, in the same manner as in Example 1, the electrical characteristics of the obtained zinc oxide varistor were evaluated. Table 25 shows the sample composition, and Table 26 shows the evaluation results of the electrical characteristics.

[0161]

[Table 25]

[0162]

[Table 26]

As can be seen from (Table 25) and (Table 26), the zinc oxide varistor manufactured by the method for manufacturing a zinc oxide varistor according to the present invention has a long-term DC load and a surge. On the other hand, the absolute value of the change rate ΔV _1mA / V _1mA of the rising voltage V _1mA was 5% or less, and the reliability was excellent. In addition, as shown in (Table 26), there was little variation in the electrical characteristics within the lot.

Although not shown in Table 26, when a zinc oxide varistor was prepared using the ceramic composition of this example, the variation in the electrical characteristics between lots was as small as the variation within the lot. Specifically, the process capability index was _1.03 for the sample using the conventional composition without heat treatment with the standard width of ± ₁ % at V _{1 mA} was 1.333. As a result, the yield was 90% in the sample using the conventional composition without heat treatment, whereas it was 95% in this example, which was a remarkable improvement. In addition, Bi ₂ O ₃ / TiO ₂ / Sb ₂ O ₃ / C
When the amount of the r ₂ O ₃ / B ₂ O ₃ synthetic powder added exceeded 20 parts by weight, the sample could not be measured for sticking (Sample No. # 10).
9). Therefore, the added amount of the synthetic powder is 10
0.5 to 20 parts by weight is preferable with respect to 0 parts by weight.

(Comparative Example 4) A conventional manufacturing method was applied to Example 1
Three types of zinc oxide varistor using the sintered body having the same composition as 0 were manufactured.

Zinc oxide powder (ZnO), bismuth oxide powder (Bi ₂ O ₃ ), titanium oxide fine powder (TiO ₂ ), antimony oxide powder (Sb ₂ O ₃ ), chromium oxide (Cr ₂ O ₃ ), boron oxide. (B
₂ O ₃ ), cobalt oxide powder (CoO) and manganese dioxide powder (MnO ₂ ) in a weight ratio of 100: 0.88: 0.085: 0.02
: 0.01: 0.005: 0.954: 0.414 (# 1014) and 100:
1.76: 0.17: 0.04: 0.02: 0.010: 0.954: 0.414
(# 1015) and 100: 4.4: 0.425: 0.1: 0.05: 0.0
25: 0.954: 0.414 (# 1016) were blended, and these powders were mixed by a wet method and pulverized. The obtained mixed powder was dried and molded into a disc shape. These compacts are heated in the air at a heating rate of 50 ° C / hour and heated at 950 ° C for 2 hours.
After holding for a time, the temperature was decreased at a temperature decrease rate of 50 ° C./hour to obtain a sintered body. The sample size of the sintered body is 1.2 mm thick and the diameter is 14
It was mm.

Thereafter, a zinc oxide varistor was manufactured in the same manner as in Example 1. Further, in the same manner as in Example 1, the electrical characteristics of the obtained zinc oxide varistor were evaluated. Table 27 shows the sample composition, and Table 28 shows the evaluation results of the electrical characteristics.

[0168]

[Table 27]

[0169]

[Table 28]

As can be seen from (Table 27) and (Table 28), the zinc oxide varistor manufactured by the conventional manufacturing method is
V _1mA after a DC load of 0.2 watts was remarkably reduced, and the absolute value of the DC load change rate ΔV _1mA / V _1mA was 10% or more. Also, the absolute value of the surge change rate exceeded 10%, and the reliability was extremely low. Further, as shown in (Table 28), there was a large variation within the lot.

Although not shown in Table 28, the variation in the electrical characteristics of the zinc oxide varistor manufactured by the conventional method between lots was even greater than the variation within the lot. There were many varistor whose V _{1mA / mm} and α value were lower than those shown in (Table 28).

This shows that the sintering temperature of 950 ° C. is too low in the case of the composition prepared by the conventional method, so that it is unsuitable for the production of zinc oxide varistor. Even if the conventional method is used, a varistor having considerably good characteristics can be obtained by firing at a high temperature, for example, 1250 ° C. But,
If a good quality sintered body cannot be obtained without raising the sintering temperature in this manner, there are various disadvantages as described above.

As described above, as is clear from the comparison between Example 10 and Comparative Example 4, the zinc oxide varistor manufactured by the low temperature sintering manufacturing method according to the present invention has initial electrical characteristics, reliability, and lot and lot lots. Any variation in electrical characteristics between them is superior to the zinc oxide varistor manufactured by the conventional manufacturing method.

Example 11 Bismuth oxide powder (particle size: about 2 to 3 μm) and antimony oxide powder (particle size: about 2 to 3)
μm) was mixed at a weight ratio of 85:15, and heat treatment was performed at 550 ° C. for 5 hours in an air atmosphere. On the other hand, separately from this, powder of bismuth oxide (particle size of about 2 to 3
μm) and chromium oxide fine powder (particle size: 0.5-1.5μ)
m) was mixed at a weight ratio of 75:25, and this mixture was subjected to heat treatment at 600 ° C. for 10 minutes in an air atmosphere. In addition, bismuth oxide powder (particle size: about 2 to 3 μm) and boron oxide fine powder (particle size: about 2 to 3 μm) were used in a weight ratio of 9
The mixture was mixed at 3: 7, and this mixture was heat-treated at 600 ° C. for 10 minutes in an air atmosphere. These three components were mixed at a weight ratio of 3.0: 0.3: 0.3, and wet-milled for 18 hours in a Monomaron pot using stabilized zirconia balls to obtain (bismuth oxide / oxidation). An antimony / chromium oxide / boron oxide synthetic powder (particle size of about 2 to 3 μm) was obtained.

Zinc oxide powder (average particle size 0.3 μm), Bi ₂ O ₃ / Sb ₂ O ₃ / Cr ₂ O ₃ / B ₂ O ₃ synthetic powder, cobalt oxide powder (particle size about 0.5 to 1) 0.5 μm) and manganese dioxide powder (particle size of about 2 to 3 μm) in a weight ratio of 10
The powder blended so as to be 0: 3.6: 0.80: 0.40 was wet-mixed and pulverized for 18 hours in a Monomaron pot using stabilized zirconia balls. The obtained powder was dried, and aluminum nitrate containing 0.0013 parts by weight of aluminum oxide in terms of Al ₂ O ₃ was added in the form of an aqueous solution to 100 parts by weight of zinc oxide to prepare a blended powder. Then, it was pressed into a disk shape. The obtained molded body is heated in the atmosphere at a heating rate of 150 ° C./hour to 80
0 ° C, 850 ° C, 900 ° C, 1000 ° C, 1050 ° C,
After holding at each temperature of 1100 ° C for 15 hours, the cooling rate 1
The temperature was lowered at 50 ° C./hour to obtain a sintered body. The sample size of the sintered body was 1.2 mm in thickness and 14 mm in diameter.

A zinc oxide varistor was manufactured in the same manner as in Example 1 below. Further, in the same manner as in Example 1, the electrical characteristics of the obtained zinc oxide varistor were evaluated. Table 29 shows the sample composition, and Table 30 shows the evaluation results of the electrical characteristics.

[0177]

[Table 29]

[0178]

[Table 30]

As can be seen from Tables 29 and 30, 80
As a result of firing over a temperature range of 0 to 1100 ° C., the zinc oxide varistor produced by the porcelain composition of this example has a high rising voltage, and is resistant to a long-term DC load and surge. Change rate of rising voltage V _1mA △
The absolute value of V _1mA / V _1mA was 5% or less, and the reliability was excellent. In addition, as shown in Table 30, there was little variation in the electrical characteristics within the lot.

Although not shown in Table 30, when a zinc oxide varistor was prepared using the porcelain composition of this example, the variation in the electrical characteristics between lots was as small as the variation within the lot. Specifically, the process capability index has a standard width of V _1mA.
Was ± 5%, which was 1.0 in the sample using the conventional method and composition without heat treatment, and was 1.33. As a result of the above, the yield of the product was 90% in the sample using the conventional composition without heat treatment, whereas it was significantly improved in this example to 95%.

Example 12 Powder of bismuth oxide (particle size: about 2 to 3 μm) and fine powder of antimony oxide (particle size: about 2 to 2 μm)
3 μm) in a weight ratio of 70:30,
Heat treatment was performed at 500 ° C. for 30 minutes. On the other hand, separately from this, bismuth oxide powder (particle size of about 2 to 3 μm) and chromium oxide fine powder (particle size of about 0.5 to 1.5 μm) were prepared as 60:
The mixture was mixed in a weight ratio of 40, and this mixture was heat-treated at 600 ° C. for 2 hours. Further, bismuth oxide powder (particle size of about 2
3 μm) and boron oxide fine powder (particle size: about 2 to 3 μm) were mixed at a weight ratio of 85:15 and heat-treated at 450 ° C. for 1 hour. Next, these three are 2.5: 0.3: 0 by weight.
2, 2.5: 0.2: 0.3, 2.5: 0.1: 0.4, 2.0: 0.
6: 0.4, 2.0: 0.4: 0.6, 2.0: 0.2: 0.8, 1.5:
Bi ₂ O ₃ / Sb ₂ O ₃ / Cr ₂ O composed of 8 kinds of bismuth oxide / antimony oxide / chromium oxide / boron oxide by mixing in a ratio of 1.0: 0.5, 1.5: 0.5: 1.0 and finely pulverized.
_{A 3} / B ₂ O ₃ synthetic powder (particle size of about 2 to 3 μm) was obtained.

Zinc oxide powder, Bi ₂ O ₃ / S composed of bismuth oxide / antimony oxide / chromium oxide / boron oxide
b ₂ O ₃ / Cr ₂ O ₃ / B ₂ O ₃ synthetic powder, cobalt oxide powder (particle size about 0.5 to 1.5 μm) and manganese dioxide powder (particle size about 2 to 3 μm) in a weight ratio of 100. : 3.0: 0.50: 0.50 were compounded, mixed by a wet method and pulverized. The powder obtained is dried, and Al ₂ O is added to 100 parts of the zinc oxide.
Aluminum nitrate containing aluminum oxide in a weight of 0.0020 in terms of ₃ was added in the form of an aqueous solution, followed by pressure molding, crushing and molding into a disk shape. The obtained molded body was heated in the atmosphere at a temperature rising rate of 300 ° C./hour, held at 1000 ° C. for 1 hour, and then cooled at a temperature lowering rate of 100 ° C./hour to obtain a sintered body. The sample size of the sintered body was 1.2 mm in thickness and 14 mm in diameter.

A zinc oxide varistor was manufactured in the same manner as in Example 1 below. Further, in the same manner as in Example 1, the electrical characteristics of the obtained zinc oxide varistor were evaluated. Table 31 shows the sample composition, and Table 32 shows the evaluation results of the electrical characteristics.

[0184]

[Table 31]

[0185]

[Table 32]

From (Table 31) and (Table 32), the zinc oxide varistor manufactured by the method for manufacturing a zinc oxide varistor according to the present invention has a large α value, and has a long DC load and surge for a long time. However, the absolute value of the change rate ΔV _1mA / V _1mA of the rising voltage V _1mA was 5% or less, which was excellent in reliability.

Example 13 Bismuth oxide powder (particle size: about 2 to 3 μm) and antimony oxide fine powder (particle size: about 2 to 2 μm)
(3 μm) and boron oxide fine powder (particle size: about 2 to 3 μm) are mixed at a weight ratio of 97.5: 2: 0.5, and the mixture is heated to 450 ° C.
For 5 hours. On the other hand, separately from this, powder of bismuth oxide and fine powder of chromium oxide (particle size of about 0.5-
1.5 μm) in a weight ratio of 75:25, and this mixture was heat-treated at 550 ° C. for 5 hours. These two were blended in a weight ratio of 10: 1 and finely pulverized to obtain a synthetic powder of bismuth oxide / antimony oxide / chromium oxide (particle size: about 2 to 3 μm).

Zinc oxide powder, bismuth oxide / antimony oxide / chromium oxide synthetic powder, cobalt oxide powder (particle size of about 0.5 to 1.5 μm) and manganese dioxide powder (particle size of about 2 to 3 μm) were weighed. Ratio 100: 3.3: 0.80
: Powders blended so as to be 0.40 were mixed by a wet method and pulverized. The obtained powder is dried, and aluminum nitrate containing an aluminum oxide content of 0.0013 in terms of Al ₂ O ₃ is added to the zinc oxide 100 in the form of an aqueous solution, followed by pressure molding and crushing into a disk shape. Molded into. The obtained molded body is heated in the atmosphere at a heating rate of 150 ° C./hour to 900
After the temperature was kept at 15 ° C for 15 hours, the temperature was lowered at a temperature lowering rate of 50 ° C / hour to obtain a sintered body. The sample size of the sintered body was 1.2 mm in thickness and 14 mm in diameter.

A zinc oxide varistor was manufactured in the same manner as in Example 1 below. Further, in the same manner as in Example 1, the electrical characteristics of the obtained zinc oxide varistor were evaluated. Table 33 shows the sample composition, and Table 34 shows the evaluation results of the electrical characteristics.

[0190]

[Table 33]

[0191]

[Table 34]

As can be seen from (Table 33) and (Table 34)
Manufactured by the method for manufacturing a zinc oxide varistor according to the present invention.
Zinc oxide varistor has a high rising voltage and
Between DC load and surge
Rising voltage V_1mARate of change ΔV _1mA/ V_1mAHas an absolute value of 5
% Or less, the reliability was excellent. Also shown in (Table 34)
As described above, the variation in the electrical characteristics within the lot is small.
Was.

Although not shown in Table 34, when a zinc oxide varistor was produced by this manufacturing method, the variation in the electrical characteristics between lots was as small as the variation within the lot. As a result of the above, the yield of products was significantly improved.

Example 14 Bismuth oxide powder (particle size: about 2 to 3 μm) and antimony oxide fine powder (particle size: about 2 to 2 μm)
3 μm) and chromium oxide powder (particle size: about 0.5 to 1.5 μm)
m) in a weight ratio of 85: 10: 5 and mixed to obtain 500
It heat-processed at 1 degreeC for 1 hour. On the other hand, separately from this, powder of bismuth oxide and fine powder of boron oxide (particle size of about 2 to 3 μm) were mixed in a weight ratio of 93: 7, and this mixture was heat-treated at 600 ° C. for 10 minutes. gave. By mixing these two in a weight ratio of 8: 2 and pulverizing,
A synthetic powder of bismuth oxide / antimony oxide / chromium oxide / boron oxide (particle size of about 2 to 3 μm) was obtained.

The zinc oxide powder, the bismuth oxide / antimony oxide / chromium oxide synthetic powder, the cobalt oxide powder (particle size of about 0.5 to 1.5 μm) and the manganese dioxide powder (particle size of about 2 to 3 μm) were mixed in a weight ratio. Is 100: 4.0: 0.50: 0.
It was blended so as to be 50, mixed by a wet method and pulverized. The powder obtained is dried, and to this 100 parts of zinc oxide
Aluminum nitrate containing an aluminum oxide content of 0.0013 in terms of Al ₂ O ₃ was added in the form of an aqueous solution, followed by pressure molding, crushing and molding into a disk shape. The resulting molded body is heated in the air at a heating rate of 150 ° C / hour to 900 ° C for 12 hours.
After holding for a while, the temperature was lowered at a temperature lowering rate of 50 ° C./hour to obtain a sintered body. Sample size of the sintered body is 1.2mm thick, diameter is 14mm
Met.

A zinc oxide varistor was manufactured in the same manner as in Example 1 below. Further, in the same manner as in Example 1, the electrical characteristics of the obtained zinc oxide varistor were evaluated. Table 35 shows the sample composition, and Table 36 shows the evaluation results of the electrical characteristics.

[0197]

[Table 35]

[0198]

[Table 36]

From (Table 35) and (Table 36), the zinc oxide varistor manufactured by the method for manufacturing a zinc oxide varistor according to the present invention has a large α value and can be used for a long time DC load and surge. , Change rate of rising voltage V _1mA △ V _1mA /
The absolute value of V _1mA was 5% or less, which was excellent in reliability.

Example 15 Bismuth oxide powder (particle size: about 2 to 3 μm) and antimony oxide fine powder (particle size: about 2 to 3 μm)
3 μm) in a weight ratio of 85:15, and
Heat treatment was performed at 0 ° C. for 5 hours. On the other hand, separately from this, powder of bismuth oxide (particle size of about 2 to 3 μm), fine powder of chromium oxide (particle size of about 0.5 to 1.5 μm) and boron oxide powder (particle size of about 2 to 3 μm) were prepared. By mixing in a weight ratio of 93: 2: 4, heat-treating this mixture at 500 ° C for 1 hour, and pulverizing both the heat-treated mixed powders,
A synthetic powder of bismuth oxide / antimony oxide / chromium oxide / boron oxide (particle size of about 2 to 3 μm) was obtained.

Zinc oxide powder (ZnO), bismuth oxide / antimony oxide / chromium oxide / boron oxide synthetic powder,
Cobalt oxide powder (CoO) (particle size 0.5-1.5μ
m) and manganese dioxide powder (MnO ₂ ) (particle size: approx.
m) in a weight ratio of 10 while changing the amount of the bismuth oxide / antimony oxide / chromium oxide / boron oxide synthetic powder.
Powders blended so as to be 0: 4.0: 0.954: 0.414 were mixed by a wet method and pulverized. Dry the resulting blended powder,
It was pressed into a disk shape. Then, the obtained molded body was heated in the atmosphere at a temperature rising rate of 150 ° C./hour, held at 900 ° C. for 2 hours, and then cooled at a temperature lowering rate of 50 ° C./hour to obtain a sintered body. The sample size of the sintered body is 1.2 mm thick and the diameter is 14
It was mm.

A zinc oxide varistor was manufactured in the same manner as in Example 1 below. Further, in the same manner as in Example 1, the electrical characteristics of the obtained zinc oxide varistor were evaluated. Table 37 shows the sample composition, and Table 38 shows the evaluation results of the electrical characteristics.

[0203]

[Table 37]

[0204]

[Table 38]

As can be seen from (Table 37) and (Table 38), the zinc oxide varistor manufactured by the method for manufacturing a zinc oxide varistor according to the present invention has a long-term DC load and a surge. On the other hand, the absolute value of the change rate ΔV _1mA / V _1mA of the rising voltage V _1mA was 5% or less, and the reliability was excellent. Further, as shown in (Table 38), the variation in the electrical characteristics within the lot was small.

Although not shown in Table 38, when the zinc oxide varistor was produced by this manufacturing method, the variation in the electrical characteristics between lots was as small as the variation within the lot. As a result of the above, the yield of products was significantly improved.

[0207]

INDUSTRIAL APPLICABILITY As described above, the zinc oxide porcelain composition of the present invention is capable of producing a zinc oxide varistor excellent in electrical characteristics such as non-linear resistance characteristics and reliability by low-temperature sintering with high yield. It is possible to provide a zinc oxide-based porcelain composition capable of achieving the above.

The zinc oxide porcelain composition of the present invention has a firing temperature of 750 ° C. to 1100 when producing a sintered body thereof.
Even if the temperature is lowered to as low as ℃, the growth of zinc oxide particles can be uniformly promoted. Then, a sintered body of zinc oxide particles having a narrow particle size distribution is obtained. As a result, a zinc oxide varistor having excellent electrical characteristics and reliability can be manufactured with a high yield. Further, since the zinc oxide-based porcelain composition of the present invention can be sintered at a low temperature, it reduces power consumption during sintering,
It is possible to reduce the consumption of the furnace material and container of the electric furnace used for sintering, and greatly contribute to energy saving and resource saving. In addition, the method for producing a zinc oxide-based ceramic composition of the present invention can provide a method for easily producing a zinc oxide-based ceramic composition that can achieve the above excellent effects.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a zinc oxide varistor formed by using a zinc oxide based ceramic composition according to an embodiment of the present invention.

[Explanation of symbols]

 11 Zinc oxide sintered body 12 Electrode 13 Lead wire

Claims (26)

[Claims] 1. 0.5 to 20 parts by weight of a synthetic powder prepared by subjecting a mixture of at least bismuth oxide powder and antimony oxide powder to a heat treatment at 400 to 700 ° C. to 100 parts by weight of zinc oxide powder. , At least one powder selected from cobalt oxide and manganese oxide.
A zinc oxide porcelain composition containing 1 to 5.0 parts by weight. 2. The synthetic powder comprises bismuth oxide powder, antimony oxide powder, boron oxide (B ₂ O ₃ ) and boric acid (H ₃
The zinc oxide porcelain composition according to claim 1, wherein the mixture consisting of at least one boron compound powder selected from BO ₃ ) is a synthetic powder prepared by heat treatment at 400 ° C to 700 ° C. 3. A mixture of synthetic powder comprising bismuth oxide powder, antimony oxide powder and chromium oxide powder is 40.
The zinc oxide porcelain composition according to claim 1, which is a synthetic powder prepared by being subjected to a heat treatment at 0 ° C to 700 ° C. 4. The synthetic powder comprises bismuth oxide powder, antimony oxide powder, chromium oxide powder, and boron oxide (B ₂
O ₃ ) and at least one boron compound powder selected from boric acid (H ₃ BO ₃ ), a mixture of 400 ° C. to 700 ° C.
The zinc oxide porcelain composition according to claim 1, which is a synthetic powder prepared by being subjected to a heat treatment at ℃. 5. A synthetic powder, which is prepared by subjecting a mixture of bismuth oxide powder and antimony oxide powder to heat treatment at 400 ° C. to 700 ° C., as a synthetic powder, bismuth oxide powder, boron oxide (B ₂ O ₃ ), and The mixture with at least one boron compound powder selected from boric acid (H ₃ BO ₃ ) is 40
The zinc oxide porcelain composition according to claim 1, wherein two kinds of synthetic powders, a synthetic powder prepared by being subjected to a heat treatment at 0 ° C to 700 ° C, are used. 6. A synthetic powder prepared by subjecting a mixture of bismuth oxide powder and antimony oxide powder to heat treatment at 400 ° C. to 700 ° C. and a mixture of bismuth oxide powder and chromium oxide powder at 400 ° C. The zinc oxide porcelain composition according to claim 1, wherein two kinds of synthetic powders, a synthetic powder prepared by being subjected to a heat treatment at 700 ° C. and a synthetic powder, are used. 7. A synthetic powder, which is prepared by subjecting a mixture of bismuth oxide powder and antimony oxide powder to a heat treatment at 400 ° C. to 700 ° C. as a synthetic powder, bismuth oxide powder, boron oxide (B ₂ O ₃ ), and The mixture with at least one boron compound powder selected from boric acid (H ₃ BO ₃ ) is 40
A synthetic powder prepared by heat treatment at 0 ° C to 700 ° C and a mixture of bismuth oxide powder and chromium oxide powder are mixed with each other.
The zinc oxide porcelain composition according to claim 1, wherein three kinds of synthetic powders, that is, a synthetic powder prepared by being subjected to heat treatment at 00 ° C to 700 ° C, are used. 8. A mixture of bismuth oxide powder, antimony oxide powder and chromium oxide powder is 400 ° C. as a synthetic powder.
Synthetic powder prepared by heat treatment at ~ 700 ° C, bismuth oxide powder, boron oxide (B ₂ O ₃ ) and boric acid
The mixture of at least one boron compound powder selected from (H ₃ BO ₃ ) and the synthetic powder prepared by heat treatment at 400 ° C. to 700 ° C. are used, and two kinds of synthetic powder are used. Zinc oxide-based porcelain composition. 9. A bismuth oxide powder as a synthetic powder,
Antimony oxide powder, boron oxide (B ₂ O ₃ ) and boric acid
A mixture of at least one boron compound powder selected from (H ₃ BO ₃ ) is prepared by heat treatment at 400 ° C. to 700 ° C., and a mixture of bismuth oxide powder and chromium oxide powder is 400 ° C. The zinc oxide porcelain composition according to claim 1, wherein two kinds of synthetic powders, a synthetic powder prepared by being subjected to a heat treatment at 700 ° C. and a synthetic powder, are used. 10. A synthetic powder prepared by subjecting a mixture of bismuth oxide powder and antimony oxide powder to heat treatment at 400 ° C. to 700 ° C. as a synthetic powder, bismuth oxide powder, chromium oxide powder, and boron oxide (B ₂ O ₃ ) and boric acid
The mixture of at least one boron compound powder selected from (H ₃ BO ₃ ) and the synthetic powder prepared by heat treatment at 400 ° C. to 700 ° C. are used, and two kinds of synthetic powder are used. Zinc oxide porcelain composition 11. The aluminum component is 0.0 in terms of aluminum oxide with respect to 100 parts by weight of zinc oxide powder.
0062 to 0.372 parts by weight are contained.
0. The zinc oxide porcelain composition according to any one of 0. 12. A synthetic powder prepared by subjecting a mixture of a bismuth oxide powder and a chromium oxide powder to a heat treatment at 400 ° C. to 700 ° C., wherein the mixing ratio of the bismuth oxide powder and the chromium oxide powder is a molar ratio. The chromium oxide powder is equimolar or more with respect to the bismuth powder.
2. A zinc oxide porcelain composition according to any one of 1. 13. Bismuth oxide powder and boron oxide (B
₂ O ₃ ) and at least one boron compound powder selected from boric acid (H ₃ BO ₃ ) and subjected to heat treatment at 400 ° C. to 700 ° C. to prepare a mixture of bismuth oxide powder and oxidation. The mixing ratio with at least one boron compound powder selected from boron (B ₂ O ₃ ) and boric acid (H ₃ BO ₃ ) is 80:20 to 20:80 in terms of molar ratio.
2. A zinc oxide porcelain composition according to any one of 1. 14. A step of subjecting a mixture of at least bismuth oxide powder and antimony oxide powder to heat treatment at 400 ° C. to 700 ° C. and pulverizing to prepare a synthetic powder, and 0.5 to 20 parts by weight of the synthetic powder. , Zinc oxide powder 100
A method for producing a zinc oxide-based porcelain composition, which comprises the step of adding to a raw material powder containing 0.1 to 5 parts by weight of at least one powder selected from cobalt oxide powder and manganese oxide powder. 15. As synthetic powder, bismuth oxide powder, antimony oxide powder, boron oxide (B ₂ O ₃ ), and boric acid (H ₃₎
The zinc oxide porcelain composition according to claim 14, which is obtained by using a synthetic powder obtained by subjecting a mixture comprising at least one boron compound powder selected from BO ₃ ) to a heat treatment at 400 ° C to 700 ° C and pulverizing the mixture. Manufacturing method. 16. The synthetic powder obtained by subjecting a mixture of bismuth oxide powder, antimony oxide powder, and chromium oxide powder to heat treatment at 400 ° C. to 700 ° C. and pulverizing as the synthetic powder. 2. A method for producing a zinc oxide-based porcelain composition. 17. A synthetic powder, bismuth oxide powder, antimony oxide powder, chromium oxide powder, and at least one boron compound powder selected from boron oxide (B ₂ O ₃ ) and boric acid (H ₃ BO ₃ ). A mixture consisting of
The method for producing a zinc oxide porcelain composition according to claim 14, wherein a synthetic powder obtained by subjecting to a heat treatment at ˜700 ° C. and crushing is used. 18. A synthetic powder, which is obtained by subjecting a mixture of bismuth oxide powder and antimony oxide powder to heat treatment at 400 ° C. to 700 ° C. and pulverized as the synthetic powder, bismuth oxide powder and boron oxide (B ₂ O ₃ ). And a mixture with at least one boron compound powder selected from boric acid (H ₃ BO ₃ ) 4
The method for producing a zinc oxide porcelain composition according to claim 14, which comprises using two kinds of synthetic powders, which are a synthetic powder obtained by performing heat treatment at 00 ° C to 700 ° C and pulverizing. 19. A synthetic powder obtained by subjecting a mixture of bismuth oxide powder and antimony oxide powder to heat treatment at 400 ° C. to 700 ° C. and pulverizing as a synthetic powder, and a mixture of bismuth oxide powder and chromium oxide powder at 400 ° C. ~ 700 ° C
15. The method for producing a zinc oxide-based porcelain composition according to claim 14, wherein two kinds of synthetic powders, that is, a synthetic powder obtained by subjecting to heat treatment and pulverization, are used. 20. A synthetic powder, which is obtained by subjecting a mixture of bismuth oxide powder and antimony oxide powder to heat treatment at 400 ° C. to 700 ° C. and pulverized as the synthetic powder, bismuth oxide powder and boron oxide (B ₂ O ₃ ). And a mixture with at least one boron compound powder selected from boric acid (H ₃ BO ₃ ) 4
Three kinds of synthetic powder obtained by subjecting a mixture of bismuth oxide powder and chromium oxide powder to a heat treatment at 400 ° C. to 700 ° C. The synthetic powder of claim 1 is used.
4. The method for producing the zinc oxide porcelain composition according to 4. 21. As a synthetic powder, 400 of a mixture of bismuth oxide powder, antimony oxide powder and chromium oxide powder is used.
Of a bismuth oxide powder and at least one boron compound powder selected from boron oxide (B ₂ O ₃ ) and boric acid (H ₃ BO ₃ ). The method for producing a zinc oxide-based porcelain composition according to claim 14, wherein two kinds of synthetic powders, that is, a synthetic powder obtained by subjecting the mixture to a heat treatment at 400 ° C to 700 ° C and pulverizing the mixture are used. 22. As the synthetic powder, bismuth oxide powder, antimony oxide powder, boron oxide (B ₂ O ₃ ), and boric acid (H ₃
A mixture of at least one boron compound powder selected from BO ₃ ) is pulverized by heat treatment at 400 ° C to 700 ° C, and a mixture of bismuth oxide powder and chromium oxide powder is 400 ° C to 700 ° C. 15. The method for producing a zinc oxide-based porcelain composition according to claim 14, wherein two kinds of synthetic powders, that is, a synthetic powder obtained by subjecting to heat treatment and pulverization, are used. 23. As the synthetic powder, a synthetic powder obtained by subjecting a mixture of bismuth oxide powder and antimony oxide powder to heat treatment at 400 ° C. to 700 ° C. and crushing, bismuth oxide powder, chromium oxide powder, and boron oxide (B ₂ O ₃ ) and at least one boron compound powder selected from boric acid (H ₃ BO ₃ ) and subjected to heat treatment at 400 ° C. to 700 ° C. and pulverized to obtain a synthetic powder, and two types of synthetic powders. The method for producing a zinc oxide-based porcelain composition according to claim 14, which comprises: 24. 0.00062 to 0.372 parts by weight in terms of aluminum oxide based on 100 parts by weight of the zinc oxide powder and the raw material powder containing zinc oxide powder as a main component to which synthetic powder is added. The method for producing a zinc oxide-based porcelain composition according to any one of claims 14 to 23, which is added. 25. The mixture ratio of bismuth oxide powder and chromium oxide powder in a synthetic powder obtained by subjecting a mixture of bismuth oxide powder and chromium oxide powder to heat treatment at 400 ° C. to 700 ° C. and crushing is a molar ratio. The method for producing a zinc oxide-based porcelain composition according to claim 19, wherein the chromium oxide powder has an equimolar amount or more with respect to the bismuth oxide powder. 26. Bismuth oxide powder and boron oxide (B
₂ O ₃ ) and at least one boron compound powder selected from boric acid (H ₃ BO ₃ ) and subjected to heat treatment at 400 ° C. to 700 ° C. and pulverized to obtain a bismuth oxide powder in a synthetic powder. The mixing ratio with at least one boron compound powder selected from boron oxide (B ₂ O ₃ ) and boric acid (H ₃ BO ₃ ) is 80:20 to 20:80 in terms of molar ratio, 18, 20 or 22. A method for producing a zinc oxide-based porcelain composition according to any one of 21.