JPH02213101A - Manufacture of grain-boundary barrier type high capacitance ceramic varistor - Google Patents

Abstract

PURPOSE:To obtain a ceramic varister having excellent characteristics in a laminated type and the like by adding specified sintering accelerator, semiconductor accelerator, oxygen conductive solid electrolyte and grain-boundary depletion-layer forming agent into perovskite type oxide powder whose main component is SrTiO3, molding the powder by mixing and compression, performing sintering and reduction, and performing heat treatment in an oxidizing atmosphere. CONSTITUTION:To perovskite type oxide powder whose main component is SrTiO3, the following materials are added: 0.1-5.0wt.% sintering accelerator which mainly forms liquid phase at high temperatures; 0.05-2.0wt.% semiconductor accelerator which mainly forms perovskite- phase solid solution; 0.1-10.0wt.% oxygen conductive solid electrolyte which also serves the role of a grain-growth controlling agent; and 0.2-7.0wt.% grain-boundary depletion-layer forming agent Sr(Mn1/2Ta1/2) which also serves as a grain-growth controlling agent. The materials are mixed and compressed, and the molded body is obtained. Thereafter, sintering and reduction are performed at 800-1,500 deg.C. Then, heat treatment is performed in an oxidizing atmosphere at 900-1, 150 deg.C. Thus an electrode 3 is formed. For example, platinum pastes for inner electrodes 2 are printed on a green sheets. The material is sintered in an atmosphere at 1,400 deg.C. Reduction is performed in hydrogen at 1,300 deg.C. Then, heat treatment is performed in atmosphere at 950 deg.C. Thus the outer electrode 3 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of manufacturing a grain boundary barrier type high capacitance ceramic varistor.

Conventional Technology Conventionally, by insulating the grain boundaries of this type of ceramic oxide semiconductor, it has been possible to obtain a capacitor body with a much higher apparent dielectric constant than conventional ceramic dielectrics. Are known. Furthermore, it is known that when electrodes are formed on these capacitor bodies, a so-called varistor can be obtained in which current flows rapidly at a threshold voltage. For example, oxidized steel (Cub) and oxidized steel (Cub) and oxidized In a grain boundary barrier type high capacitance ceramic varistor material obtained by diffusing bismuth (Bi2O3,) from the surface of the sintered body to form a depletion layer at the grain boundaries and forming a high resistance layer at the grain boundaries, While maintaining the characteristics of a voltage at which a current of 1 mA begins to flow, that is, a rising voltage of 50 to 200 V/mm and a nonlinear resistance index α of 10, a material with a large apparent dielectric constant of 20.000 to ioo, ooo can be obtained. It is being In addition, here, we will discuss Cub, Bi2, which is a diffusion substance that has often been used in conventional manufacturing methods.
Regarding the role of O3, C
uO forms an electron trap center at the grain boundaries of the sintered body, traps electrons present near the grain boundaries of the n-type semiconductor 5rTiO3 crystal, and forms a depletion layer where no electrons exist near the grain boundaries. work to do. A grain boundary barrier type high capacitance ceramic varistor stores charge on both sides of the insulating depletion layer thus formed and is configured as a capacitor, but when a voltage above the threshold voltage is applied, current rapidly flows and the varistor Characteristics emerge.

As a result, the apparent permittivity of the sintered body is the dielectric constant of 5rTi○3 (~200), the ratio of the grain size of 5rTfO3 in the sintered body and the thickness of the grain boundary depletion layer (grain size/depletion layer). The value is approximately multiplied by the thickness of The thickness of the grain boundary depletion layer in a typical SrTiO3 sintered body is approximately 0.2 μm per grain boundary, and in the SrT″i03 sintered body, the grain size is 2 μm and 20 μm.
, 200 μm, the apparent permittivity is 2.000.20.000.200.000, respectively.

In addition, Bi2O3 has β-Bi203 phase and δ-Bi2Ch
In the case of a phase, it is known to be a good conductor of oxygen, and when Bi2O3 is applied to the surface of a sintered body and heat treated, Bi2O3 first diffuses along the grain boundaries of the sintered body, and then exists at the grain boundaries. Oxygen is transported by diffusion from the outside to the inside of the sintered body along Bi2O3, and serves to supply oxygen necessary for forming grain boundary depletion layers. This type of grain boundary barrier type high capacitance ceramic varistor has excellent characteristics such as capacitance and temperature characteristics, and is therefore widely used in industry. In addition,
The above-mentioned grain boundary barrier type high capacitance ceramic varistor is made of oxidized steel that is fired at high temperatures during boat fishing to make the crystal grains in the sintered body as large as possible, and then made into a paste around the sintered body. It is manufactured through a process in which B12 (h, CuO, etc.) is diffused into the interior of the sintered body and oxidized by applying bismuth oxide, etc., and then performing heat treatment.

Problems to be Solved by the Invention When attempting to manufacture a particularly large laminated grain boundary barrier type high capacitance ceramic varistor with a large capacitance using the manufacturing method described above, the electrode spacing should be 10 to 100 μm or more. In order to narrow the size, the growth of crystal grains in the sintered body must be suppressed to small and uniform grain sizes ranging from 1 μm to several dozen μm, and during the process, Bi2O3, CuO, etc. It is necessary to diffuse homogeneously from the surface to the inside, and the presence of a metal electrode layer has a particularly large effect, which tends to cause variations in properties.Furthermore, if the thickness is thick, Bi2O3, CuO, etc. Since it is difficult to diffuse the ions, there are problems such as the size of the element being limited.

In addition, since the electrode spacing is narrow, the sintered body is required to have microscopically homogeneous properties, and therefore, the material composition is required to be homogeneous.

The present invention provides a grain boundary barrier type high capacitance ceramic varistor, such as a laminated type, which solves these problems.

Means for Solving the Problems In order to solve these problems, the present invention provides SrTi
A sintering accelerator that mainly forms a liquid phase at high temperatures, a semiconductor accelerator that is mainly dissolved in the perovskite phase, a grain growth control electrolyte, and a grain growth control agent are added to the perovskite-type oxide powder containing 03 as the main component. A grain boundary depletion layer forming agent that also serves as a material is added, and the material is sintered at high temperature to form a semiconductor. After that, an oxygen diffusion treatment and an oxidation treatment of the grain boundary depletion layer forming agent are performed in an oxidizing atmosphere. A grain boundary barrier type high capacitance ceramic varistor is obtained.

Function As described above, the present invention provides a berovskite-type oxide powder mainly composed of SrTiO3 with a sintering accelerator that forms a liquid phase at high temperatures, a semiconducting accelerator that is mainly dissolved in the perovskite phase, A solid electrolyte with good oxygen conductivity, which also serves as a grain growth control agent, and a grain boundary depletion layer forming agent, which also serves as a grain growth control agent, are added, mixed and formed, then sintered at high temperature to become a semiconductor, and then placed in an oxidizing atmosphere. Inside, oxygen is diffused and the grain boundary depletion layer forming agent is oxidized to form a carrier depletion layer along the grain boundaries, and this depletion layer provides a high quality varistor.

Example An overview of the present invention will be explained.

A berovskite-type oxide powder containing SrTiO3 as a main component is supplemented with a sintering accelerator that forms a liquid phase at high temperatures, a semiconducting accelerator that is mainly dissolved in the perovskite phase, and an oxygen-rich agent that also functions as a grain growth control agent. When a conductive solid electrolyte and a grain boundary depletion layer forming agent that also serves as a grain growth control agent are added and mixed, pressure molded, and sintered at high temperature in a reducing atmosphere, the sintering process mainly forms a liquid phase at high temperature. The crystallization promoter is composed of a grain boundary depletion layer forming agent that also serves as a grain growth control agent, a semiconductor formation promoter, and SrT i
Promote the reaction and solid solution of the 01 product with the berovskite type oxide. However, on the other hand, the SrTiO3 main component phase is deprived of some oxygen by the reduction action.

It becomes an n-type semiconductor material. The grain boundary depletion layer forming agent is SrTi
Sr has a considerably different lattice constant compared to Os.
The solid solution range for TiO3 is quite small and SrTiO3
The amount of solid solution in is several percent or less in terms of molar ratio. Therefore, at high temperatures, part of the grain boundary depletion layer forming agent, which was dissolved in large quantities in SrTiOx, diffuses from the microcrystalline grains of the SrTiO3 phase to the surrounding grain boundaries and precipitates uniformly during the cooling process during firing. . When such a sintered body is heat-treated in an oxidizing atmosphere, oxygen freely diffuses in the solid electrolyte with good oxygen conductivity, mainly composed of ZrO2, which was present at the grain boundaries, and oxides containing manganese etc. precipitated at the grain boundaries. , is further oxidized by the oxygen that reaches it.

As a result, electron trap centers mainly composed of manganese oxide or the like are formed at the grain boundaries. These electron trap centers are low resistance n-type SrTi formed by reduction.
Electrons are taken away from within the Os semiconductor crystal grains, and as a result, a carrier depletion layer is formed along the grain boundaries. The depletion layer obtained in this way has good insulating properties, and when a voltage is applied to the sintered body, charges are stored on both sides of the depletion layer, resulting in a high-quality varistor. Cub after semiconductorization,
It is possible to easily obtain an excellent grain boundary barrier type high capacitance ceramic varistor without requiring a process of applying and diffusing Bi203 or the like.

FIG. 1 shows a laminated grain boundary barrier type high capacitance ceramic varistor which is an embodiment of the present invention, where ■ indicates a grain boundary barrier type high capacitance ceramic, 2 indicates an internal electrode, and 3 indicates an external electrode. FIG. 2 shows a grain boundary barrier type high capacitance ceramic varistor which is another embodiment of the present invention, 4 is a grain boundary barrier type high capacitance ceramic, 5 is an electrode, and 6 is a lead wire. It is.

A specific example of one embodiment of the present invention will be described below.

(Example 1) Titanyl strontium oxalate (SrTiO(C204)
Sintering accelerator T i 02-A I 2038102 (2
0+30:45wt ratio) from 0.05 to 6.0wt%
, 0.02 to 3.0 wt% of the semiconductor accelerator Nb2O5, which is mainly solid dissolved in the perovskite phase.1 0.05 to 12 of the oxygen-conducting solid electrolyte Zr○2, which also serves as a grain growth control agent.
．． 0wt%, grain boundary depletion layer forming agent S that also serves as a grain growth control agent
r(Mn1/zTabz2)03 (0.1~8.0w
t%) was added, mixed well, and then calcined at 900°C. After wet pulverization, drying, granulation, molding, and 1
Sintered at 300℃, wet-pulverized again, made into a paste using resin and organic solvent, printed and laminated with platinum paste for internal electrodes, and sintered at 1400℃ in the air.
After sintering at 1,300℃, hydrogen reduction was performed at 95
A heat treatment was performed at 0° C., and the electrodes were adjusted to connect the inner electrode and the outer electrode 7 to produce a laminated grain boundary barrier type high capacitance ceramic varistor as shown in FIG. 1, and its electrical characteristics were measured.

The measured bundle is shown in Table 1. In addition, the sintering accelerator T'1
02A I203-8 i 02 (20: 30:
45wtjt) is a commercially available T i 02. Al 2
is, S i 02 powders were weighed according to a predetermined weight ratio, mixed, calcined at 1200° C., and pulverized.

Furthermore, a grain boundary depletion layer forming agent S r (M
n, +z2Ta1/2) 03 is commercially available 5rCOs, T
a205. It was obtained by mixing MnCO3 and the like, calcining at 100°C, and pulverizing.

The size of the laminated varistor after firing is approximately 4 mm square and approximately 0.61 mm thick, and the thickness of the dielectric layer is approximately 70 μm.
It consisted of 8 layers of dielectric material. The apparent dielectric constant ε of this material was calculated from the capacitance value (measurement 1 k&) of the laminated varistor. The grain size of the crystal grains in the sintered body is determined by polishing the cut surface and applying Bi2O3 metal soap to the polished surface.
The grain boundaries were determined by heat treatment at 1000° C. to make them clearer and observed with an optical microscope.

As is clear from Table 1, the sintering accelerator T is added to 5rTjO3.
i 02-A 1203-S i 02 is 0.1 to 5
．． 0 wt%, semiconductor accelerator Nb2O5 is 0.05-2
．． 0 wt%, solid electrolyte Z "02 is 0.1 to 10.0 w
t%, grain boundary depletion layer forming agent Sr(
This material, which is obtained by adding 0.2 to 7.0 wt% of Mn1/2Ta+72)Os and firing, has a uniform particle size and extremely excellent varistor properties.It also exhibits high dielectric properties and is suitable for high capacitance varistors. Can be used as That is, as a result of microscopic observation, the particle size of the fine particles of the sintered body was well aligned, and the diameter was approximately 9.
The dielectric loss is less than 2.0% in μm, and the apparent permittivity is 9.
It was over 000. The rising voltage V 1 mA of the material used as a varistor is 250 to 400 V/m, and V
Nonlinear resistance index α between 1 m A and vO, ImA
takes a value of 10 or more in most cases. In addition, we measured the surge resistance as a varistor, the limiting voltage ratio representing non-linear resistance characteristics in a high current range, the temperature coefficient of rising voltage V1 mA, the temperature coefficient of capacitance, etc., and found satisfactory values.

It should be noted that if the amount of the sintering accelerator added exceeds 5%, the sintered body may be deformed or adhered, making it impractical.

(Example 2) Commercially available industrial strontium titanate (SrTiOv)
TiO2MgO5i02 system (e.g. 30:30
: 40wt% ratio), TiO2-MnO-SiO2 system (
For example, 10:50:40wt% ratio), T i 02-A
1203-8 i 02 series (e.g. 20:35:45
1.0 wt % of a sintering accelerator that mainly forms a liquid phase at high temperatures (wt % ratio), and 0.4 w t of a semiconducting accelerator Y2O3 that is mainly dissolved in the bevlovskite phase.
%, solid electrolyte with good oxygen conductivity, ZrO, which also serves as a grain growth control agent
0.2 to 10.0 wt% of 2, grain boundary depletion layer forming agent S r (Mn1/2Ta+7t) 0 which also serves as a grain growth control agent
Add 0.4 to 6.0 wt% of 3 (after mixing)
It was calcined at 900°C. After wet grinding, drying and granulation
After molding into a disk shape and firing at 1380°C in a reducing atmosphere consisting of 95% nitrogen to 5% hydrogen,
A grain boundary barrier type high capacitance ceramic varistor as shown in FIG. 2 was prepared by heat treatment at .degree. C. and silver electrodes were formed on both surfaces of the disk, and its electrical characteristics were measured. The measurement results are shown in Table 2.

The sintering accelerator is, for example, TiO2MgO3i02 (fl (for example, 30:30:40 wt% ratio)), commercially available TiO2rMgO, Ss02
The powders were weighed and mixed at a predetermined weight ratio, calcined at 1.200°C, and pulverized. Furthermore, a grain boundary depletion layer forming agent S r (Mn1/2Ta1/z)03 which also serves as a grain growth control agent
was obtained by mixing commercially available SrcO3, Ta2CO5, and MnCO3, calcining the mixture at 900°C, and pulverizing the mixture.

(Left below) As is clear from Table 2, TiO2M is added to 5rTiOs.
1.0 wt% of a sintering accelerator such as go-SiO2 that mainly forms a liquid phase at high temperatures, 0.4 wt% of a semiconductor accelerator Y2O3, and 0% of an oxygen-conducting electrolyte ZrO2 that also serves as a grain growth control agent. .2 to 8, OwtOb, grain boundary depletion layer forming agent that also serves as a grain growth control agent or 0.4 to 6.0 wt%
The material obtained by adding and firing the material exhibits extremely excellent varistor and dielectric properties, and can be used as a high capacitance varistor. The electrical properties of the materials used in these devices are approximately the same as the materials of the first embodiment.

<Example 3> Commercially available industrial strontium titanate (SrT i 0
3) 3.0 wt% of the sintering accelerator that mainly forms a liquid phase at high temperatures of the MgOS i02 system (for example, 30:30:40 wt% ratio), the semiconductor accelerators WO3, Nbzos, L a203.
0.05 to 2.0 wt% YzO3, 1.5 wt% oxygen conductive solid electrolyte ZrO2 that also serves as a grain growth control agent, grain boundary depletion layer forming agent S rO,B that also serves as a grain growth control agent
Bao, +Cao, + (Mn1/zTa+z2)03
Or S ro, 6B a, o, tc ao, 2 (
M n 1/2T a I/2) 03 by 2゜Owe%
After adding and mixing thoroughly, it was calcined at 900°C. After wet pulverization, it is dried, granulated, molded, fired at 1380°C in a reducing atmosphere consisting of 95% nitrogen and 5% hydrogen, and heat treated at 1050°C in the air to form an electrode. A grain boundary barrier type high capacitance ceramic varistor was fabricated and its electrical properties were measured. The measurement results are shown in Table 3.

The sintering accelerator T i 02-MgO-8i O2 system (30: 30: 40 wt ratio) is a commercially available Ti
Weigh the powders of 02, MgO, 5i02 at a predetermined weight ratio.
The mixture was mixed, calcined at 1200°C, and ground.

Furthermore, grain boundary depletion layer forming agents that also serve as grain growth control agents include commercially available S r CO3, B a CO3, Ca CO3 ° Ta205. MnCO5 was mixed, calcined at 900°C, and pulverized.

(Left below) As is clear from Table 3, 5rTi (T i 0 in h
Sintering accelerator such as 2-MgO-8i 02 series is 3, Ov
t%, 0.05 to 2.0 wt% of semiconductor accelerator, 1.5 wt% of solid electrolyte ZrO which also served as grain growth control agent, 2.0 wt% of grain boundary depletion layer forming agent which also served as grain growth control agent. The material obtained by adding % and firing shows excellent varistor and dielectric properties and can be used as a high capacitance varistor. The electrical properties of the materials used in these devices are approximately the same as the materials of the first embodiment.

(Example 4) Grain boundary depletion layer forming agent Sr (Mn2/3W1/z
)03 (0.1 to 8.0 wt%), a grain boundary depletion layer forming agent S r (M rH/3w1/3 ) Os (
0.1 to 10.0 wt%), and the manufacturing method including the manufacturing method of other materials, sintering accelerator, etc., and the measuring method are also the same as in Example 1.

The measurement results are shown in Table 4.

In addition, a grain boundary depletion layer forming agent S r which also serves as a grain growth control agent
(Mn2/3W1/z)03 is commercially available SrCO3゜WO
3, M n C03 was mixed and calcined at 1000°C,
Obtained by crushing.

(Left below) As is clear from Table 4, the sintering accelerator T i 02-A I203-8 i 02 is o, i ~
5.0wt%, semiconductor accelerator Nb2O5 is 0.05~
2.0 wt%, solid electrolyte ZrO2 is 0.1-1, O,
0wt%, grain boundary depletion layer forming agent S that also serves as a grain growth control agent
r(Mn2/zW+7z)03 is 0.2 to 8.0 wt%
This material obtained by adding and firing has uniform particle size and extremely excellent varistor properties, and also exhibits high dielectric properties.
Can be used as a high capacitance varistor. That is, as a result of microscopic observation, the fine particles of the sintered body were found to have a uniform particle size, with an average particle size of 6°08 m, a dielectric loss of 2.0% or less, and an apparent dielectric constant of 6500 or more. The rising voltage V1 mA of the material as is 350-500 V
/m, the nonlinear resistance index α between V+mA and VO, 1mA takes a value of almost 10 or more. We also measured the surge resistance as a varistor, the limiting voltage ratio representing the non-plane resistance characteristics in the high current range, the temperature coefficient of the rise voltage VImA, the temperature coefficient of capacitance, etc., and found that we obtained satisfactory values. .

It should be noted that if the amount of the sintering accelerator added exceeds 5%, the sintered body may be deformed or adhered, making it impractical.

(Example 5) Example 20 Grain boundary depletion layer forming agent Sr (Mn2/zW+7z
)03 (0.1 to 6.Owt%), a grain boundary depletion layer forming agent S r (M nysWI/s ) Os (0
．． 4 to 4.0 wt%) is replaced with a solid electrolyte with good oxygen conductivity Zro2 (0.2 to 7.0 wt%) which also serves as grain growth control. 0
wt%), and the manufacturing method including the manufacturing method of other materials and materials such as sintering accelerator, and the measuring method are also the same as in Example 2. The measurement results are shown in Table 5. In addition, a grain boundary depletion layer forming agent S r which also serves as a grain growth control agent
(Mn2/zW+7z)03 is commercially available S rCO3,
WO3 and MnCO3 were mixed, calcined at 900°C, and pulverized.

(Margin below) As is clear from Table 5 (, Ti 0 in SrTiO3
2-MgO-8i (h) is mainly a sintering accelerator that forms a liquid phase at high temperatures, 1.Owt%, a semiconductor accelerator Y2O3 is 0.4wt%2, a good oxygen conductor that also serves as a grain growth control agent. Solid electrolyte ZrO2 is 0.2-8.0wt52 Grain boundary depletion layer forming agent which also serves as grain growth control agent is 0.4-3.0w
The material obtained by adding t% and firing shows extremely excellent varistor properties and dielectric properties, and can be used as a high capacitance varistor. The electrical properties of the materials of these devices are approximately equal to those of the fourth embodiment.

(Example 6) Grain boundary depletion layer forming agent S ro, eB a of implementation f113.

Cao, + (Mn2/zW+7z)03 or Sro
, 6B ao, 2c ao, 2 (Mn172Ta1/2
) Instead of adding 2.0 wt% of 03, the grain boundary depletion layer forming agent S rg, aB aQ, l Cao, + (M
n2/yW2ys> Ch or S rg, s B
ao, 2 Cao2 (M n2/3w2/3 ) 0
The grain boundary depletion layer forming agent which added 2.0 wt% of 3 and also served as a grain growth control agent was commercially available 5rCOz.

It was obtained by mixing BaCO3, CaCO3, WO3, and MnCO3, calcining the mixture at 900°C, and pulverizing it.

Note that the manufacturing method including the manufacturing method of other materials and materials such as sintering accelerator, and the measuring method are also the same as in Example 3.

The measurement results are shown in Table 6.

(Left below) As is clear from Table 6, Ti0 in 5rTiO3
Sintering accelerator such as 2-MgO-8i 02 series is 3.0w
t%, semiconducting accelerator is 0.05 to 2.0wt%2, solid electrolyte Zr○2 which also serves as a grain growth control agent is 1.5wt%2
Grain boundary depletion layer forming agent that also serves as a grain growth control agent is 2.0wt%
The material obtained by doping and firing shows excellent varistor and dielectric properties and can be used as a high capacitance varistor. The electrical properties of the materials used in these devices are approximately
Equivalent to the material properties of the example.

(Example 7) Grain boundary depletion layer forming agent Sr (Mn1/2Ta1/
2) Grain boundary depletion layer forming agent Sr(Mn1/2Nb+72)03(0.1~8.0wt%) instead of 03(0.1~8.0wt%)
10.0 wt %), and the manufacturing method including the manufacturing method of other materials and materials such as sintering accelerator, and the measuring method are also the same as in Example 1. The measurement results are shown in the seventh
Shown in the table. The grain boundary depletion layer forming agent Sr(Mn1/2Nb1/2)03, which also serves as a grain growth control agent, is commercially available SrC.
O3, Nb2O5°MnCO3 were mixed, calcined at 1000°C, and pulverized.

(Left below) As is clear from Table 7, the sintering accelerator Ti○2-A I203-8 i02 in SrTiO3 is 0.1 to 5.
0 wt%, and the semiconducting accelerator Nb2O5 is 0105-2.
0wt%, solid electrolyte ZrO2 is 0.1-10.0wt
%, grain boundary depletion layer forming agent S r (
This material obtained by adding 0.2 to 8.0 wt% of Mn1/pNb1/1)03 and firing it has uniform particle size and extremely excellent varistor properties.It also exhibits high dielectric properties and high electrostatic properties. Can be used as a capacitance varistor. In other words, as a result of microscopic observation, the particle size of the fine particles of the sintered body is well aligned, approximately 8 μm.
m, dielectric loss is 2.0% or less, apparent permittivity is 8,
It was over 000. The rising voltage V1 mA of the material used as a varistor is 300 to 400 V/m, and V
The nonlinear resistance index α between ImA and VO, 1 mA takes a value of almost 10 or more. We also measured the surge resistance as a varistor, the limiting voltage ratio representing non-linear resistance characteristics in the high current range, the temperature coefficient of rising voltage V + mA, the temperature coefficient of capacitance, etc., and the values were satisfactory. I got it.

It should be noted that if the amount of the sintering accelerator added exceeds 5%, the sintered body may be deformed or adhered, making it impractical.

(Example 8) Grain boundary depletion layer forming agent Sr (Mn+7tTa+7
2) Grain boundary depletion layer forming agent S r (Mn1/2Nb1/2) 03 (0.4
~6.0wt%) is replaced with a solid electrolyte with good oxygen conductivity ZrO2 (0.2~7.0wt%) which also serves as grain growth control.
%), and manufacturing methods and measuring methods, including methods for manufacturing other materials and materials such as sintering accelerators, are also implemented f! It is the same as fiI2. The measurement results are shown in Table 8.

In addition, a grain boundary depletion layer forming agent S r which also serves as a grain growth control agent
(M n 1/2 N b I/2) 03 is commercially available Sr
CO3°N b205. Mix M n COs, 9
The product was calcined at 00°C and pulverized.

(Left below) It is clear from Table 8 that (,5rTiO3 has Ti(h
1.0 wt% of sintering accelerator such as MgO-3fO2 that mainly forms a liquid phase at high temperatures, and 1.0 wt% of sintering accelerator such as MgO-3fO2;
O3 is 0.4 wt% 2 grain growth control agent ZrO2 with good oxygen conductivity is 0.2 to 8.0 wt% 1 grain growth I
Grain boundary depletion layer forming agent that also serves as 11 Ojii is 0.4 to 6.0w
The wood material obtained by firing and adding t% shows extremely excellent varistor properties and dielectric properties, and can be used as a high capacitance varistor. The electrical properties of the materials used in these devices are approximately the same as those of the seventh embodiment.

(Example 9) Grain boundary depletion layer forming agent S ro, sB ao, I of Example 3
Cao, + (Mn+z27a1/1)03 or 5r
(1,6B ao, yc ao, 2(Mn+7tTa+
72) Instead of adding 2.0 wt% of 03, grain boundary depletion layer forming agent S r3sBao, ICao, +(Mn1
/2Nb1/2)03 or S r6. aB ao,!
c ao, 2(M n I/2N b I/2) 03 was added at 2.0 wt%, and the grain boundary depletion layer forming agent that also served as a grain growth control agent was commercially available SrCO3゜BaCO3, CaC.
Mix O3, NbxOs, MnCO3 and heat to 900℃
It was obtained by calcining and pulverizing.

Note that the manufacturing method including the manufacturing method of other materials and materials such as sintering accelerator, and the measuring method are also the same as in Example 3.

The measurement results are shown in Table 9.

(Margin below) As is clear from Table 9, 5rTiOs has T i 0
2 Sintering accelerator such as MgO-8i 02 series is 3.0
wt%, semiconducting accelerator Y2O3 is 0.5 or 1.0w
t%1 solid electrolyte ZrO2 which also serves as a grain growth control agent.
5wt%, grain boundary depletion layer forming agent which also serves as grain growth control agent is 2
This material obtained by adding 0 wt% and firing shows excellent varistor properties and dielectric properties, and can be used as a high capacitance varistor. That is, as a result of microscopic observation, on the free surface of the sintered body? The particle size of each composition of the M lattice was well matched, ranging from 7.0 to 12.0 μm, the dielectric loss was 2.0% or less, and the apparent dielectric constant was s, ooo or more. Also, the rising voltage V1m of the material as a varistor
A is 350-400 V/wa, V1mA-Vo
, 1 mA, the nonlinear resistance index α takes a value of almost 10 or more. In addition, surge resistance as a varistor, temperature coefficient of rise voltage V + mA.

We measured the temperature coefficient of capacitance, etc., and found satisfactory values. The electrical properties of the materials used in these devices are approximately the same as those of the seventh embodiment.

In addition, in Examples 2.3.5, 6, and 8.9, 5rT
A solid electrolyte with good oxygen conductivity that also serves as a sintering accelerator, a semiconductor accelerator, and a TL growth control agent, a grain growth control agent, and a grain boundary depletion layer forming agent are added to iOs, and the mixture is mixed and pressure-molded.
Even when sintering and reduction were performed at 800 to 1500°C, and then heat treatment was performed at 900 to 1150°C in an oxidizing atmosphere, the same results as in each example were confirmed.

In addition, in Examples 1 and 4.7, a sintering accelerator, a semiconducting accelerator, and a well-oxygen-conducting solid electrolyte which also served as a grain growth controlling agent, and a grain boundary depletion layer forming agent were added to SrTiO3. After adding, mixing and pressurizing, 1200 to 1
It is fired at 500°C, finely pulverized, formed into layers alternately with noble metal internal electrode materials, and heated to 1250-150°C in advance in air.
Calcined at 00°C, then heated at 800°C in a reducing atmosphere containing hydrogen.
Reduction at ~1500℃, 900~1i5 in oxidizing atmosphere
Even when the heat treatment was performed at 0° C., the same results as in each example were confirmed.

Effects of the Invention As described above, according to the present invention, a sintering accelerator mainly consisting of a mixture and forming a liquid phase is added to a perovskite-type oxide powder containing strontium titanate (S rT i O3) as a main component. 0.1 to 5.0 wt, and 0.05 to 2.0 wt.
0 wt%, 0.1 to 10.0 wt% of an oxygen-conducting solid electrolyte ZrO2 that also serves as a grain growth control agent, and a grain boundary depletion layer forming agent that also serves as a grain growth control agent. After the body is pressure molded, it is subjected to a sintering and reduction process at 1250 to 1500°C, and then heated to 900 to 1150°C in an oxidizing atmosphere.
After heat treatment is performed to form electrodes, or after forming the powder into layers alternately with noble metal internal electrode material, 1.
A grain boundary barrier type high capacitance ceramic varistor with good conductivity can be obtained by performing a sintering/reduction process at 250 to 1500°C, then heat treatment at 900 to 1150°C in an oxidizing atmosphere, and then forming an external electrode. This has the effect of being able to obtain the following.

[Brief explanation of the drawing]

FIG. 1 is a diagram explaining the structure of a laminated grain boundary barrier type high capacitance ceramic varistor which is an embodiment of the present invention, and FIG. FIG. 3 is a diagram illustrating the structure of a capacitive ceramic varistor. 1.4... Grain boundary barrier type high capacitance ceramics, 2... Internal electrode, 3... External electrode, 5... Electrode, 6... ·····Lead.

Claims (15)

[Claims] (1) A sintering accelerator (0.1 to 5.0 w
t%), a semiconducting accelerator (0.05 to 2.0 wt%) mainly dissolved in the perovskite phase, and a solid electrolyte with good oxygen conductivity, ZrO_2 (0.1 to 10 wt%), which also serves as a grain growth control agent.
0wt%), and a grain boundary depletion layer forming agent Sr(Mn_1_/_2Ta_1_/_2)O_ which also serves as a grain growth control agent.
3 (0.2 to 7.0 wt%), mixed and pressure molded, and then sintered and reduced at 800 to 1500°C.
A method for manufacturing a grain boundary barrier type high capacitance ceramic varistor, which is then subjected to heat treatment at 900 to 1150°C in an oxidizing atmosphere to form an electrode. (2) At least TiO_2-M as a sintering accelerator
gO-SiO_2 system, TiO_2-MnO-SiO_2
2. The method for manufacturing a grain boundary barrier type high capacitance ceramic varistor according to claim 1, wherein the ceramic varistor is selected from the group consisting of TiO_2-Al_2O_3-SiO_2 system. (3) As a semiconductor accelerator, at least WO_3,
2. The method for manufacturing a grain boundary barrier type high capacitance ceramic varistor according to claim 1, wherein an oxide (0.05 to 2.0 wt%) selected from Nb_2O_5, La_2O_3, and Y_2O_3 is added. (4) Sr(Mn_2_/_3W_1_/_3)O_3(0.
2. The method for manufacturing a grain boundary barrier type high capacitance ceramic varistor according to claim 1, characterized in that 2 to 8.0 wt%) is added. (5) Sr(Mn_2_/_3W_1_/_3)O_3(0.
2 to 8.0 wt%), and at least TiO_2-MgO-SiO_2 system, TiO_2-
MnO-SiO_2 system, TiO_2-Al_2O_3-
The method for manufacturing a grain boundary barrier type high capacitance ceramic varistor according to claim 1, wherein the varistor is selected from SiO_2 series. (6) Sr(Mn_2_/_3W_1_/_3)O_3(0.
2 to 8.0 wt%), and the semiconducting accelerator is WO_
3. The method for manufacturing a grain boundary barrier type high capacitance ceramic varistor according to claim 1, comprising an oxide (0.05 to 2.0 wt%) selected from among 3, Nb_2O_5, La_2O_3, and Y_2O_3. (7) Sr (Mn_1_/_2Nb_1_/_2)O_3(
2. The method for manufacturing a grain boundary barrier type high capacitance ceramic varistor according to claim 1, characterized in that 0.2 to 8.0 wt%) is added. (8) Sr(Mn_1_/_2Nb_1_/_2)O_3(0
．． 2 to 8.0 wt%) and at least TiO_2-MgO-SiO_2 system, TiO_2 as a sintering accelerator.
-MnO-SiO_2 system, TiO_2-Al_2O_3
-SiO_2. The method for manufacturing a grain boundary barrier type high capacitance ceramic varistor according to claim 1. (9) Sr(Mn_1_/_2Nb_1_/_2)O_3(0
．． 2 to 8.0 wt%), and the semiconducting accelerator is WO.
_3, Nb_2O_5, La_2O_3, Y_2O_3
Oxide selected from (0.05-2.0wt%)
A method for manufacturing a grain boundary barrier type high capacitance ceramic varistor according to claim 1. (10) Strontium titanate (SrTiO_3)
A sintering accelerator (0.1 to 5.0 wt%) and a semiconducting accelerator (0.
05 to 2.0 wt%), solid electrolyte ZrO_2 (0.1 to 10.0 wt%) which also serves as a grain growth control agent, and grain boundary depletion layer forming agent Sr_1_-_x_ which also serves as a grain growth control agent.
−_yBa_xCa_y(Mn_1_/_2Ta_1_
/_2) O_3 (0<x+y≦1) (0.2~
7.0wt%), mixed and pressure molded, 1
A method for manufacturing a grain boundary barrier type high capacitance ceramic varistor, which comprises performing sintering and reduction at 250 to 1500°C, and then heat treatment at 900 to 1150°C in an oxidizing atmosphere to form an electrode. (11) Sr_1_-_x_-_yBa_xCa_x (Mn
_2_/_3W_1_/_3)O_3 (however, 0<x
The method for manufacturing a grain boundary barrier type high capacitance ceramic varistor according to claim 10, characterized in that +y≦1) (0.2 to 8.0 wt%) is added. (12) Sr_1_-_x_-_yBa_xCa_x (Mn
_2_/_3Nb_1_/_3)O_3(However, 0<
The method for manufacturing a grain boundary barrier type high capacitance ceramic varistor according to claim 10, characterized in that x+y≦1) (0.2 to 8.0 wt%) is added. (13) Strontium titanate (SrTiO_3)
A sintering accelerator (0.1 to 5.0 wt%) and a semiconducting accelerator (0.
05 to 2.0 wt%), solid electrolyte ZrO_2 (0.1 to 10.0 wt%), which also serves as a grain size control agent, and Sr (Mn_1_/_2Ta), which also serves as a grain boundary depletion layer forming agent and grain size control agent.
_1_/_2) After adding O_3 (0.2 to 7.0 wt%), mixing and pressurizing, heat at 1200 to 1500°C in the atmosphere.
This is then finely pulverized and formed into layers alternately with noble metal internal electrode materials, and pre-fired in the air at 1250-1500°C, then heated at 800-150°C in a reducing atmosphere containing hydrogen.
Reduction at 0°C, then 900-1150°C in an oxidizing atmosphere
A method for manufacturing a laminated grain boundary barrier type high capacitance ceramic varistor that is heat-treated. (14) Sr(Mn_2_/_3W_1_/_3)O_3(
14. The method for manufacturing a grain boundary barrier type high capacitance ceramic varistor according to claim 13, characterized in that 0.2 to 8.0 wt%) is added. (15) As a grain boundary depletion layer forming agent that also serves as a grain growth control agent, Sr(Mn_2_/_3Nb_1_/_2)O_3
14. The method for manufacturing a grain boundary barrier type high capacitance ceramic varistor according to claim 13, characterized in that 0.2 to 8.0 wt% of the ceramic varistor is added.