JP2001325973A - Ceramic film and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high quality ceramic film which is suitable for mass- production, and has a possibility of reducing a manufacturing cost. SOLUTION: The ceramic film and its manufacturing method are composed of printing, and drying/baking on a ceramic base body with a paste containing a ceramic raw material powder of viscosity 0.1-1,000 Pa.s.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-quality ceramic film which is suitable for mass production, is inexpensive to manufacture, and has a high viscosity. TECHNICAL FIELD The present invention relates to a ceramic film obtained by printing on a substrate, drying and firing, a method for producing the same, and a solid oxide fuel cell using the ceramic film.

[0002]

2. Description of the Related Art The prior art will be described by taking a cylindrical type solid electrolyte fuel cell as an example. A solid oxide fuel cell is disclosed in Japanese Patent Publication No. 1-59705.
The solid oxide fuel cell has a cylindrical cell composed of a porous support tube-air electrode-solid electrolyte-fuel electrode-interconnector. When oxygen (air) is supplied to the air electrode side and gaseous fuel (H2, CH4, etc.) is supplied to the fuel electrode side, a potential is generated between the air electrode and the fuel electrode, and power is generated.

As a material for the air electrode, Japanese Patent Publication No. 1-5970
5 is LaMnO3, and JP-A-2-288159 is LaMnO3.
Perovskite-type oxide ceramics such as _1-x Sr _x MnO ₃ have been proposed. There is also a type in which an air electrode also serves as a support tube (air electrode support tube). The dimensions of the cathode support tube are generally an outer diameter of 10 to 20 mm, a thickness of 1 to 2 mm, and a total length of 1
２2 m.

As the solid electrolyte membrane, a thin film having oxygen ion permeability and no gas permeability is required, and a yttria-stabilized zirconia (YSZ) type or CeO ₂ type is used. Generally, the thickness is about 30 to 2000 μm. Production methods include CVD / EVD, plasma spraying,
A slurry coating method, a thermal spray + filling method, and the like have been proposed.

[0005] The interconnector has excellent electrical conductivity, is gas tight, has durability in both oxidation and reduction, and has a coefficient of thermal expansion of other components such as yttria-stabilized zirconia (YSZ). Properties such as similarity and low reactivity with other constituent materials are required. Various materials have been proposed, but having the most excellent characteristics with respect to the required performance described above, La
_1-x M _x CrO ₃ , M: Sr, Ca, is generally used. As a manufacturing method, a CVD / EVD method, a slurry coating method, a plasma spraying method, and the like have been proposed. Japanese Patent Application Laid-Open No. 7-32075 discloses a method of manufacturing by a slurry coating method.
After baking the air electrode support by 7 or the like, a dense air electrode and interconnector are formed by wet dipping.
A firing method has been proposed.

[0006] For the fuel electrode, a fired layer of a composite powder obtained by mixing and mixing NiO and YSZ is mainly used.
iO is reduced to Ni during the operation of the SOFC, and the layer becomes a Ni / YSZ cermet film. As a film forming method, a slurry coating + EVD method, a wet dipping method, and the like have been proposed.

[0007]

As a method of forming the film successively, there is a CVD / EVD method. If a film is formed by this method, the performance can be improved. It must be performed under the physical conditions of the atmosphere, and the production cost is high and not practical.

As a film forming method, there is a wet dipping method. The wet dipping method is an effective method with a low cost as a film forming method, but has a drawback that the slurry is applied even to a non-film forming portion and the yield of raw materials is reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a high-quality ceramic film suitable for mass production, low production cost, a high-quality ceramic film, and a method of manufacturing the same. An object of the present invention is to provide a solid oxide fuel cell to which the present invention is applied.

[0010]

According to a first aspect of the present invention, there is provided a first method for printing a paste containing a ceramic raw material powder and having a viscosity of 0.1 to 1000 Pa · s on a substrate. And a second step of drying and firing the substrate after that, and a method of manufacturing a ceramic film.

According to the present invention, by limiting the paste viscosity, it is possible to provide not only a ceramic film at a predetermined position but also a high-quality ceramic film without peeling of the film after firing. . The reason for this is that when printing on a substrate using a paste of less than 0.1 Pa · s, the paste has poor fixability to the substrate, so that a film shape of a predetermined size cannot be maintained after printing.
This is because a paste having a viscosity higher than Pa · s has too high a fixing property on the substrate, so that the end of the printed surface becomes thick and the film may be peeled off after firing.

[0012] In the second invention, the paste further includes a binder, and the content of the binder is 3 to 100 parts with respect to 100 parts of the ceramic raw material powder. I will provide a.

According to the present invention, by limiting the amount of the binder, not only can a film having good adhesion to the substrate be produced, but also a ceramic film which does not adversely affect the substrate after firing can be provided. The reason for this is that if the amount of the binder is less than 3 parts, the film obtained by printing and firing may have poor adhesion to the substrate and may be peeled off. On the other hand, if it exceeds 100 parts, the adhesiveness is improved, but the firing shrinkage of the film after firing becomes too large, and the substrate may be warped or cracked. The appropriate amount of the binder varies depending on the function of the film. For example, in the case of a dense ceramic film, the amount is preferably about 5 to 40 parts.

In the third invention, the printing speed is 1 ×
A method for producing a ceramic film according to the first invention or the second invention, which is 10 ^{−4 to} 10 m · s ⁻¹ .

According to the present invention, a uniform ceramic film can be provided at a predetermined position by limiting the printing speed. The reason is that if it is less than 1 × 10 ⁻⁴ m · s ⁻¹ , it takes a long time to form a film, and the film is deteriorated during the film formation. On the other hand, it is difficult to produce a high quality ceramic film because the paste having a viscosity of 0.1 to 1000 Pa · s described in claim 1 having a viscosity of 10 m · s ⁻¹ or more causes unevenness on the film surface. That's why.

According to a fourth aspect of the present invention, there is provided the method for producing a ceramic film according to any one of the first to third aspects, wherein the force (printing pressure) applied to the substrate during printing is 1 × 10 ³ Pa or more. provide.

According to the present invention, a uniform ceramic film can be provided at a predetermined position by limiting the printing pressure. The reason for this is that when printing is performed with a printing pressure of less than 1 × 10 ³ Pa, the printing surface becomes uneven, and it is difficult to produce a high-quality ceramic film. In the present invention, the upper limit of the printing pressure is not particularly limited, but the printing is preferably performed at a printing pressure lower than the compressive strength of the substrate. The reason for this is that if printing is performed with a printing pressure higher than the compressive strength of the substrate, the substrate will be damaged and a film cannot be produced.

According to a fifth aspect of the invention, there is provided a ceramic film manufactured by the method for manufacturing a ceramic film according to any one of the first to fourth inventions.

The ceramic film obtained by the present invention is suitable for mass production, and can provide a high quality ceramic film with low production cost.

According to a sixth aspect of the present invention, there is provided a solid oxide fuel cell having a ceramic membrane according to the fifth aspect of the invention, wherein the substrate is selected from the group consisting of an air electrode support and a fuel electrode support. I do.

The solid oxide fuel cell according to the present invention comprises:
A solid oxide fuel cell which is suitable for mass production and inexpensive in manufacturing cost can be provided.

According to a seventh aspect of the present invention, there is provided a solid oxide fuel cell having the ceramic film according to the fifth aspect, wherein the substrate is a porous support such as CSZ or alumina.

In the present invention, the ceramic film forms an electrolyte, a fuel electrode, an air electrode, an interconnector, etc. of a solid oxide fuel cell.

The solid oxide fuel cell according to the present invention can provide a solid oxide fuel cell suitable for mass production and inexpensive in manufacturing cost.

[0025]

Embodiments of the present invention will be described.

In order to obtain a high quality ceramic film,
The maximum warpage of a ceramic substrate having a total length of 1 m is 2.0 × 10 −3 m or less, and the surface unevenness is ± 1.
0 × 10 ⁻³ m or less, and when the ceramic substrate is a cylindrical type, the roundness is preferably 90% or more.

As the ceramic raw material powder used for obtaining a high quality ceramic film, the closer the coefficient of thermal expansion to the raw material powder used for the ceramic base is better, and the difference in expansion and contraction due to firing is preferably 10% or less. .

The method in the printing method in the above invention is not particularly limited. Screen printing, pad printing, roll printing, letterpress printing, intaglio printing and the like can be mentioned. Among these, a screen printing method is preferable, in which a uniform film can be easily obtained for various shapes.

As the binder type in the paste in the above invention, acrylic type, butyral type, cellulose type and the like are used. Polymethyl methacrylate for acrylic, PVB for butyral, EC for cellulose
Is common.

As the solvent type of the paste in the above invention, ester type, aromatic type, alcohol type and the like are used.
Ethyl acetate for ester type, toluene for aromatic type,
In alcohol systems, ethanol and the like are typical. In addition, these different solvents can be used as a mixed solvent, and a mixed solvent of toluene and ethanol is often used.

The paste in the above invention may contain a dispersant, a plasticizer, a thixotropic agent, an antifoaming agent, a drying agent, a resin, etc. in addition to the raw material powder, the binder, and the solvent.

The type of the solid oxide fuel cell in the above-mentioned invention is not particularly limited, and is applicable to any type such as a cylindrical vertical stripe type, a cylindrical horizontal stripe type, and a flat plate type.

As the substrate, an air electrode support or a fuel electrode support is generally used for the cylindrical vertical stripe type, a porous support such as CSZ is used for the cylindrical horizontal stripe type, and a fuel electrode support is used for the flat plate type.

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A description will be given of an interconnector membrane of a solid oxide fuel cell as an example. Example 1: Study of paste Preparation of paste As raw material powder, La _0.8 Ca _0.2 Cr having an average particle size of 1 μm
Using a powder of O ₃ composition, toluene as a solvent and EC as a binder, a solvent in which EC was dispersed in toluene and a La _0.8 Ca _0.2 CrO ₃ composition powder were kneaded with a three-roll mill to obtain a paste.

2. Paste conditions (1) Examination of paste viscosity The binder amount was set to 10 parts for 100 parts of the raw material powder.
By adjusting the amount of toluene, the paste viscosity is from 0.01 to
A paste of 5000 Pa · s was produced.

(2) Examination of binder amount Raw material powder 10
A paste was prepared by setting the binder amount to 1 to 200 parts with respect to 0 part. The viscosity of the prepared paste was set to 100
Pa · s.

3. Film formation (printing speed: 1 × 10^―1ms
^-1, Printing pressure: 5 × 10^FivePa) Overall length 1 × 10^―1m, outer diameter 2 × 10^―2m, gas permeation flux
5 × 10^-Fivems^-1・ Pa^―1(La_0.8Sr_0.2) M
nO_ThreeGas permeation flux 1 × 10 on cathode support ^―8ms
^-1・ Pa^―1(La)_0.8Ca_0.2) Mn
O_ThreeA film is formed and this (La_0.8Ca_0.2) MnO_ThreeOn the membrane
Screen printing method (La_0.8Ca_0.2) CrO_ThreeForming a membrane
Film and dried. Further firing at 1400 ° C., (La_0.8
Ca_0.2) CrO_ThreeDense interconnector membrane (gas permeable
Overflux ≦ 2.8 × 10^-Tenms^-1・ Pa^―1Production of
Tried.

4. Evaluation method The appearance of the film after firing and the gas permeation flux were evaluated.

5. Evaluation results (1) Examination of paste viscosity Table 1 shows the evaluation results. About the appearance of the film, 0.1P
At less than a · s, traces of the paste flowing in the circumferential direction were observed, and the area was larger than that of the predetermined film-forming portion. On the other hand, in the case of a paste having a viscosity higher than 1000 Pa · s, the film was turned up at the end. On the other hand, with respect to the denseness, a dense film having a gas permeation flux ≦ 2.8 × 10 ⁻¹⁰ m · s ⁻¹ · Pa ⁻¹ or less in the range of 0.05 to 1000 Pa · s was obtained. 0.1-100 from the viewpoint of appearance and denseness of the film
0 Pa · s was found to be preferable.

[0040]

[Table 1]

(2) Examination of Binder Amount Table 2 shows the evaluation results. Regarding the appearance of the film, when the amount of the binder was less than 3 parts, peeling of the film was recognized, and when the amount of the binder was more than 100 parts, edge turning was recognized. 3 to 1
In the range of 00 parts, there was no particular problem in appearance. On the other hand, in the denseness, a dense film having a gas permeation flux ≦ 2.8 × 10 ⁻¹⁰ m · s ⁻¹ · Pa ^{− 1} or less was obtained in the range of 5 to 40 parts. Was not obtained. From the above results, it was found that in this test, the appearance of the film was preferably in the range of 3 to 100 parts, but in consideration of the denseness of the film, the range of 5 to 40 parts was preferable.

[0042]

[Table 2]

Example 2: Study of printing method Preparation of paste As raw material powder, La _0.8 Ca _0.2 Cr having an average particle size of 1 μm
Using a powder of O ₃ composition, toluene as a solvent and EC as a binder, a solvent in which EC was dispersed in toluene and a La _0.8 Ca _0.2 CrO ₃ composition powder were kneaded with a three-roll mill to obtain a paste. (Viscosity: 100Pa.
s, binder amount: 10 parts)

2. Film formation (1) Printing speed Total length 1 × 10 ^-1 m, outer diameter 2 × 10 ^-2 m, gas permeation flux 5 × 10 ^-5 m · s ^-1 · Pa ^-1 (La _0.8 Sr _0.2 ) M
nO ₃ gas permeate stream on the air electrode support beam 1 × 10 ^{- 8} m · s
(La _0.8 Ca _0.2 ) Mn with a certain density of ^-1 · Pa ^-1
O ₃ film is formed, printing pressure 5 This (La _0.8 Ca _0.2) MnO ₃ printed on the film speed ^{1 × 10 -5 m · s -1} ~20m · s -1
Screen printing at × 10 ⁵ Pa, (La _0.8 Ca _0.2 )
A CrO ₃ film was formed and dried. Further sintering at 1400 ° C., a dense interconnector film of (La _0.8 Ca _0.2 ) CrO ₃ (gas permeation flux ≦ 2.8 × 10 ⁻¹⁰ m · s ⁻¹ · P
a- ¹ ) was attempted.

(2) Printing pressure Total length 1 × 10^―1m, outer diameter 2 × 10^―2m, gas permeation flux
5 × 10^-Fivems^-1・ Pa^―1(La_0.8Sr_0.2) M
nO_ThreeGas permeation flux 1 × 10 on cathode support ^―8ms
^-1・ Pa^―1(La)_0.8Ca_0.2) Mn
O_ThreeA film is formed and this (La_0.8Ca_0.2) MnO_ThreeOn the membrane
Printing speed 1 × 10^―1ms^-1, Printing pressure 1 × 10^Two~ 1 × 1
0⁷Screen printing with Pa, (La_0.8Ca_0.2) Cr
O_ThreeThe film was formed and dried. Firing at 1400 ° C,
(La_0.8Ca_0.2) CrO_ThreeCeramic dense film (Ga
Permeation flux ≦ 2.8 × 10^-Tenms^-1・ Pa^―1)of
Production was attempted.

4. Evaluation method The appearance of the film after firing and the gas permeation flux were evaluated.

5. Evaluation results (1) Printing speed Table 3 shows the test results. Regarding the appearance of the film after firing,
At less than 1 × 10 ⁻⁴ m · s ⁻¹ , baking was observed on the surface of the film, and at printing faster than 10 m · s ⁻¹ , unevenness was observed on the film surface. There was no particular problem in the range of 1 × 10 ^{−4 to} 10 m · s ⁻¹ . 1 × 10 ^-4 -10m in denseness
· S in the range of ^{-1 2.8 × 10 -10 m · s} - 1 · Pa -1
The following dense film was obtained, but did not become a dense film in other ranges. From the above results, the printing speed was 1 × 10
It was found that the range of ^{-4 to} 10 ms- ¹ was preferable.

[0048]

[Table 3]

(2) Printing pressure Table 4 shows the test results. About the appearance of the film, 1 × 10
^At a printing pressure of less than ³ Pa, unevenness was observed on the surface of the film,
No particular problem was observed in the range of 1 × 10 ³ to 1 × 10 ⁷ Pa. On the other hand, the gas permeation flux is 2.8 × 10 ⁻¹⁰ m · s ⁻¹ · Pa ⁻¹ when the density is 1 × 10 ³ Pa or more.
The following dense film was obtained. From this result, the printing pressure was 1
It was found that the pressure was preferably at least 10 ³ Pa.

[0050]

[Table 4]

When the printing speed is 1 × 10 ^{−4 to} 10 m · s ⁻¹ and the printing pressure is 1 × 10 ³ Pa or more, a more preferable ceramic film can be obtained.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) H01M 8/12 C04B 35/00 J F term (Reference) 4G030 AA08 AA09 AA13 AA17 AA22 AA25 AA36 BA03 CA08 CA09 GA07 GA14 GA17 4G031 AA04 AA05 AA09 AA12 AA16 AA19 AA29 BA03 CA08 CA09 GA04 GA06 5H026 AA06 BB00 BB01 BB03 EE12 HH00 HH09

Claims (7)

[Claims] 1. A first step of printing a paste containing a ceramic raw material powder and having a viscosity of 0.1 to 1000 Pa · s on a substrate, and thereafter, a second step of drying and firing the substrate. A method for producing a ceramic film, comprising: 2. The method according to claim 1, wherein the paste further contains a binder, and the content of the binder is 3 to 100 parts with respect to 100 parts of the ceramic raw material powder. 3. The printing speed is 1 × 10 ^{−4 to} 10 m.
The method for producing a ceramic film according to claim 1 or 2, wherein s- ¹ . 4. A force (printing pressure) applied to the substrate during printing.
Is 1 × 10 ³ Pa or more.
The method for producing a ceramic film according to the above item. 5. A ceramic film manufactured by the method for manufacturing a ceramic film according to claim 1. 6. The solid oxide fuel cell having a ceramic film according to claim 5, wherein the substrate is selected from the group consisting of an air electrode support and a fuel electrode support. 7. The solid oxide fuel cell according to claim 5, wherein the substrate is a porous support such as CSZ or alumina.