JP2001335388A - Ceramic film and solid electrolyte fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ceramic film, suitable for mass production, capable of reducing production cost, and having high quality. SOLUTION: A production method for a ceramic film comprises the 1st step wherein a ceramics powder containing sheet material, which contains 3-50 pts.wt. of binder, 0.5-20 pts.wt. of plasticizer based on 100 pts.wt. of ceramics raw material powder, is affixed on a base body, the 2nd step wherein a cover film on ceramics material is removed, and the 3rd step wherein the above body is baked.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the production of a high quality ceramic film which is suitable for mass production, is inexpensive in production, and has a high binder content of 3 to 50 parts by weight per 100 parts by weight of ceramic raw material powder. Plasticizer 0.5-20
The present invention relates to a method for producing a ceramic film, in which a ceramic powder-containing sheet containing parts by weight is attached to a ceramic substrate and fired, and a solid oxide fuel cell using the same.

[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 and the like. The solid oxide fuel cell has a cylindrical cell composed of a porous support tube, an air electrode, a solid electrolyte membrane, a fuel electrode, and an interconnector. When oxygen (air) is supplied to the air electrode side and gaseous fuel (H ₂ , CH _4, 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 the material of the air electrode, in the KOKOKU 1-59705 discloses LaMnO3, in JP-A 2-288159 JP has been proposed a perovskite oxide ceramics such as _{La 1-x Sr x MnO 3} . 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 10-20 mm in outer diameter, 1-2 mm in wall thickness,
The total length is 1 to 2 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. As a manufacturing method, a CVD / EVD method, a plasma spraying method, a slurry coating method, a thermal spraying + filling method, and the like have been proposed. The interconnector has excellent electrical conductivity, is gas tight, has durability in both oxidation and reduction, and has a thermal expansion coefficient similar to that of other components such as yttria-stabilized zirconia (YSZ). Characteristics such as low reactivity with other constituent materials. Although various materials have been proposed, La _{1 -x} M _x C
rO 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. As a method of preparing by a slurry coating method, a method of forming a film of a fuel electrode, an electrolyte, and an interconnector by a dipping method on a calcined porous base tube and sintering the same is proposed in Japanese Patent Application Laid-Open No. 8-185882. . For the fuel electrode, a fired layer of a composite powder obtained by mixing and mixing NiO and YSZ is mainly used, and NiO in the fired layer is reduced to Ni during the operation of the SOFC, and the Ni / YSZ cermet is formed. It becomes a film. As a film forming method, a slurry coating + EVD method, a wet dipping method, and the like have been proposed.

[0003]

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. Further, as a film forming method, a wet dipping method can be used. 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-mentioned problems, and an object of the present invention is to provide a high-quality ceramic film by a method suitable for mass production and at a low production cost.

[0005]

According to a first aspect of the present invention, a binder is used in an amount of 3 to 50 parts by weight and a plasticizer is used in an amount of 0.5 to 50 parts by weight based on 100 parts by weight of a ceramic raw material powder.
A ceramic film having a first step of attaching a ceramic powder-containing sheet containing 20 parts by weight on a substrate, a second step of peeling off a cover film on the ceramic sheet, and a third step of firing the substrate And a method for producing the same.

According to the present invention, a sheet having a limited amount of a binder and a plasticizer is attached to a substrate, and then the cover film is peeled off and fired. Can be manufactured.
The reason is that if the binder amount is less than 3 parts by weight,
There is a possibility that the ceramic film obtained by baking after sticking may be peeled off. On the other hand, if it exceeds 50 parts by weight, the firing shrinkage of the film after firing becomes too large, and the substrate may be warped or cracked. Also, if the plasticizer is 0.5
If the amount is less than the weight part, not only the adhesive strength on the ceramic substrate is poor, but also it is difficult to form a sheet. on the other hand,
If the amount exceeds 20 parts by weight, the sheet containing the ceramic powder is soft, and the sheet is deteriorated when bonded to the ceramic base. Also, if the binder alone does not contain a plasticizer, it will not adhere to the ceramic substrate. on the other hand,
If the binder is not contained only by the plasticizer, the film after firing will peel off. Therefore, both the binder and the plasticizer are indispensable for the ceramic powder-containing sheet.

In order to achieve the above object, according to a second aspect of the present invention, after a ceramics-containing sheet is attached on a substrate,
Curing at １００100 ° C. for 30 minutes or more is provided.

According to the present invention, after the sheet is adhered to the substrate, curing is performed at an appropriate temperature for a certain period of time, so that the adhesion between the ceramic sheet and the substrate is improved, and the ceramic sheet may be peeled or deformed. It is possible to peel off the cover film without performing. The reason for this is that if the temperature is lower than 15 ° C., the ceramic sheet is peeled off when the cover film is peeled off because the adhesive strength of the sheet is too weak. That's why. Curing for 30 minutes or more is intended to prevent the sheet from being peeled off or deformed when the cover film is peeled off. The term “curing” as used herein refers to a state in which the apparatus is placed under a predetermined temperature condition without a forced load.

In order to achieve the above object, the third invention provides that after the cover film is peeled off, curing is performed at 15 to 300 ° C. for 30 minutes or more.

According to the present invention, curing is performed at an appropriate temperature for a certain period of time after the cover film is peeled off, so that the ceramic sheet can be fired in a state of being sufficiently adhered to the substrate. The reason for this is that if the temperature is lower than 15 ° C., the film peels off after firing due to insufficient adhesion to the substrate, and if the temperature is higher than 300 ° C., the binder and plasticizer components in the sheet are deteriorated and the film after firing is denatured. This is because cuts or the like may occur. The curing for 30 minutes or more is to increase the adhesion so that the ceramic sheet does not peel off after firing. From the viewpoint of adhesion, a longer curing time is preferred, but a shorter curing time is preferred in consideration of manufacturing costs (time cost). For curing conditions, appropriate conditions should be examined according to sheet conditions (such as film thickness). preferable. The curing at 100 to 300 ° C. in the present invention not only improves the adhesion to the substrate, but also controls the performance (density and the like) of the film after degreased and fired. The curing temperature is more preferably 100 to 300 [deg.] C. since a film can be produced according to the required function.

According to a fourth aspect of the present invention, there is provided a method for producing a ceramic powder-containing sheet, comprising: adding a solvent to a ceramic raw material powder, a binder, and a plasticizer;
A first step of preparing a slurry having a viscosity of 0.1 to 100 Pa · s, a second step of forming the slurry on a film, and a third step of drying the formed body and evaporating a solvent component Is provided.

According to the present invention, a slurry having an appropriate viscosity is formed on a film and dried to produce a ceramic powder-containing sheet. Therefore, it is possible to produce a good ceramic sheet without unevenness in film thickness. The reason for this is that when the slurry has a viscosity of less than 0.1 Pa · s, the slurry flows out when forming into a film, and a target sheet cannot be produced. On the other hand, if the slurry exceeds 100 Pa · s, the thickness of the ceramic layer applied to the sheet is increased, and then the ceramic film obtained by firing is peeled off.
Further, if the drying of the sheet is insufficient, the sheet is liable to be deteriorated, and if a ceramic film is produced using the sheet, a high-quality film cannot be obtained. Accordingly, the degree of drying may be such that the sheet does not deteriorate when the sheet is bonded, and the drying conditions can be changed according to the application.

[0013]

Embodiments of the present invention will be described. In the film of the ceramic powder-containing sheet of the present invention, a PET film or the like is used as the material of the film. Further, a film that can be easily peeled off from the sheet after bonding to the ceramic base is better, and from this viewpoint, a type in which a release agent is attached to the film is better. The releasability can also be changed by changing the thickness of the film. Selection of the material and thickness of the film according to the performance of the sheet is an important point in obtaining a high quality ceramic film.

The shape of the ceramic powder-containing sheet in the present invention may be either a type having a film on one side only or a type having a film on both sides. The type in which both surfaces are sandwiched between films is more preferable from the viewpoint of the storability of the sheet.

[0015] As the binder type in the present invention, acrylic type, butyral type, cellulose type and the like are used. Generally, polymethyl methacrylate is used for acrylic type, PVB is used for butyral type, and EC is used for cellulose type.

As the plasticizer in the present invention, phthalic acid or the like is used. Dioctyl phthalate (D
OP), diisononyl phthalate (DIND), diisodisyl phthalate (DIDP) and the like.

In the present invention, an ester type, an aromatic type, an alcohol type, or the like is used as a solvent for the slurry. Typical examples of the ester type are ethyl acetate, those of the aromatic type are toluene, those of the alcohol type are isopropyl alcohol, and the like. In addition, these different solvents can be used as a mixed solvent, and a mixed solvent of toluene and ethanol is often used.

The slurry in the present invention includes a raw material powder,
It may contain a dispersant, a thixotropic agent, an antifoaming agent, a resin, and the like in addition to the binder, the plasticizer, and the solvent.

The method for applying the ceramic powder-containing sheet in the present invention is not particularly limited. Examples include a doctor blade method, an impregnation method, a spray coating method, and a dipping method.

In order to obtain a high quality ceramic film,
The maximum warpage of a ceramic substrate having a total length of 1 m is 5.0 mm or less, the surface irregularity is ± 2.5 mm or less, and the roundness of the ceramic substrate is 8 when the ceramic substrate is a cylindrical type.
It is preferably 0% or more.

[0021] To obtain a high-quality ceramic film, a difference in thermal expansion coefficient between the ceramic substrate is 5 × 10 ^{- 6} K ^{- 1} or less, sintering expansion difference is preferably 10% or less relative to the substrate.

The type of the solid oxide fuel cell according to the sixth and seventh aspects of the present 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. is there.

As the ceramic 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 (separator) is used for the flat plate type. .

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Interconnector of solid oxide fuel cell
This will be described by taking a film as an example. 1. Preparation of slurry As raw material powder, La having an average particle size of 1 μm_0.8Ca_0.2Cr
O_ThreeUsing composition powder, toluene and binder as solvent
As polymethyl methacrylate and DOP as plasticizer
Were mixed and kneaded with a kneader for 10 minutes. 2. Slurry conditions (1) Examination of binder amount Polymethyl methacrylate per 100 parts by weight of raw material powder
0 to 60 parts by weight, 5 parts by weight of DOP, and toluene
In addition, a slurry was prepared. Adjusting the amount of toluene
To obtain a slurry having a viscosity of 1 Pa · s. (2) Examination of the amount of plasticizer 100 parts by weight of the raw material powder was polymethyl methacrylate
20 parts by weight, and 0 to 30 parts by weight of DOP, and toluene
Was added to prepare a slurry. Adjust the amount of toluene
And a slurry having a viscosity of 1 Pa · s was obtained. (3) Investigation of slurry viscosity Polymethyl methacrylate is used for 100 parts by weight of the raw material powder.
20 parts by weight, 5 parts by weight of DOP, and toluene
A slurry was prepared. By adjusting the amount of toluene,
A slurry having a degree of 0.05 to 200 Pa · s was prepared. 3. Forming the sheet The prepared slurry is PET-filled using a doctor blade method.
Coated on the lum and dried. Coating speed of 0.02m · s
^{― 1}After drying at 50 ° C. for 15 minutes,
For 30 minutes. 4. Adhesion of sheet Total length 10cm, outer diameter 2 × 10mm, gas permeation flux 5 × 1
0^{― Five}ms^-1・ Pa ^{― 1}(La_0.8Sr_0.2) MnO_Three
Gas permeation flux 1 × 10 on cathode support^{― 8}ms^-1・
Pa^{― 1}(La)_0.8Ca_0.2) MnO_Threefilm
Is formed, and a sheet is adhered on the film, and the mixture is heated at 50 ° C. for 60 minutes.
After curing, peel off the cover film.
After curing for 20 minutes, it was baked at 1400 ° C. (La_0.8
Ca_0.2) CrO_ThreeDense interconnector membrane (gas permeable
Overflux ≦ 2.8 × 10^{― Ten}ms^{- 1}・ Pa^{― 1}Production of
Tried. 5. Evaluation method The appearance of the film after baking (whether or not there is cutting or peeling) and (La_0.8S
r_0.2) MnO_ThreeN in the cathode support_TwoGas, pressure difference 1a
tm_TwoFlow gas and (La_0.8Ca_{0 .2}) C
rO_ThreeMeasure the gas permeation flux of the interconnector membrane
Was. 6. Evaluation results (1) Examination of binder amount Table 1 shows the evaluation results.

[Table 1] Regarding the appearance of the film, the film after baking was peeled off when the amount was less than 3 parts, and the edge of the film was turned up when the amount of the binder was more than 50 parts. On the other hand, the denseness, 5-40 parts by weight gas flux ≦ 2.8 × 10 in the range of ^{- 10} m · s ^-1 ·
A dense film of Pa ^{- 1} or less was obtained. The appearance of the film is 3
Although it may be in the range of 50 to 50 parts by weight, the dense film is 5 to 40 parts by weight.
It has been found that parts by weight are preferred. (2) Examination of plasticizer amount Table 2 shows the evaluation results.

[Table 2] Regarding the appearance of the film, peeling of the film was observed at less than 0.5 part by weight, and edge turning was observed at more than 20 parts by weight. On the other hand, in the range of 0.5 to 20 parts by weight in dense gas flux ^{≦ 2.8 × 10 - 10 m ·} s -1 ·
A dense film of Pa ^{- 1} or less was obtained, but a dense film was not obtained in other ranges. From the above results, it was found that in this test, the amount of the plasticizer was preferably in the range of 0.5 to 20 parts by weight. As shown above, it was found that the ceramic powder-containing sheet preferably contained 3 to 50 parts by weight of the binder and 0.5 to 20 parts by weight of the plasticizer. (3) Examination of slurry viscosity Table 3 shows the evaluation results.

[Table 3]In the case of a sheet having a viscosity of less than 0.1 Pa · s, the film surface after firing
Are observed, and the slurry having a viscosity higher than 100 Pa · s
After baking, a turn was recognized at the end. In detail
Is in the range of 0.1 to 10 Pa · s, gas permeation flux ≦
2.8 × 10^{― Ten}ms^-1・ Pa^{― 1}The following dense film is obtained
However, a dense film could not be obtained in other ranges.
Was. From the above results, the appearance of the film was 0.1 to 100 P
It may be in the range of a · s, but as a dense film, 0.1 to 10 Pa
-It turned out that the range of s is preferable. 7. Examination of curing conditions after bonding the sheet After bonding the sheet, 5 to 150 ° C (curing time: 60)
) For 1 to 240 minutes (curing temperature: 50 ° C) and cover
The film was peeled off. Visual appearance of the sheet after peeling
Was evaluated. Table 4 (Tables 4-1 and 4-2) shows the evaluation results.
You.

[Table 4] When the temperature was lower than 15 ° C., the sheet was peeled off when the cover film was peeled off, and it could not be adhered to the substrate. 1
At 5 ° C. or higher, the sheet could be peeled off from the cover film, but at a temperature higher than 150 ° C., the sheet after peeling was deformed. On the other hand, the curing time is 1 to 1
At 0 minutes, the sheet could not be adhered to the substrate, and at 10 minutes to 30 minutes, the cover film could be peeled off, but the sheet edge was turned up. After 30 minutes or more, the film could be peeled off without any problem. 8. Curing conditions after peeling off the cover film After peeling off the cover film, 5 to 400 ° C (curing time: 120 minutes), 1 to 240 minutes (curing temperature: 80 ° C)
After curing, it was fired at 1400 ° C. The appearance of the film after firing was visually evaluated. Table 5 shows the evaluation results.

[Table 5] At a temperature lower than 15 ° C., turning over of the film was observed, and at a temperature higher than 300 ° C., a cut was observed on the surface of the film.
It was good in the range of ° C. On the other hand, the curing time is 30
When the time was less than minutes, a part of the edge was turned up, but when the time was 30 minutes or more, the film was good.

[0025]

As described above, according to the present invention, in the production of a ceramic film, the ceramic raw material powder 10 is used.
A first step of attaching a ceramic powder-containing sheet containing a binder amount of 3 to 50 parts by weight and a plasticizer of 0.5 to 20 parts by weight with respect to 0 parts by weight on a substrate, and peeling off a cover film on the ceramic sheet. Since the second step and the third step of sintering the substrate are provided, it is possible to obtain a high-performance ceramic film by a method suitable for mass production and at a low production cost.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01M 8/02 H01M 8/02 Y 8/12 8/12 C04B 35/00 G (72) Inventor's bedding Koji Koji, 2-1-1 Nakajima, Kokurakita-ku, Kitakyushu-shi, Fukuoka (72) Inventor Haruo Nishiyama 2-1-1 Nakajima, Nakagura-ku, Kokurakita-ku, Kitakyushu, Fukuoka F-term (Reference) 4G030 AA08 AA13 AA22 BA01 CA08 GA14 PA22 4G052 DA02 DA08 DB02 DC06 5H018 AA06 AS02 AS03 BB00 BB01 BB06 BB08 BB12 EE11 EE12 HH05 5H026 AA06 BB00 BB01 BB03 BB04 BB08 CX04 H05

Claims (7)

[Claims] 1. A binder material of 3 to 50 parts by weight and a plasticizer of 0.5 to 20 parts by weight based on 100 parts by weight of ceramic raw material powder.
A first step of attaching a ceramic powder-containing sheet containing parts by weight on a substrate, a second step of peeling off a cover film on the ceramic sheet, and a third step of firing the substrate further; Production method. 2. The method for producing a ceramic film, comprising: after adhering a ceramic-containing sheet on a substrate,
The method for producing a ceramic film according to claim 1, wherein curing is performed at 15 to 150 ° C for 30 minutes or more. 3. The method for producing a ceramic film according to claim 1, wherein the cover film is peeled off and then heated at 15 to 300 ° C. for 3 hours.
The method for producing a ceramic film according to claim 1, wherein the curing is performed for 0 minutes or more. 4. A method for producing a ceramic powder-containing sheet, comprising: adding a solvent to a ceramic raw material powder, a binder, and a plasticizer to produce a slurry having a viscosity of 0.1 to 100 Pa · s; A method for producing a ceramics-containing sheet, comprising: a second step of forming a slurry on a film; and a third step of drying the formed body and evaporating a solvent component. 5. A ceramic film manufactured by the method according to claim 1. 6. The solid electrolyte fuel cell according to claim 1, wherein the substrate is an air electrode support or a fuel electrode support of a solid oxide fuel cell, and the ceramic film is a constituent member other than the solid electrolyte fuel cell support. Solid oxide fuel cell. 7. The solid electrolyte according to claim 1, wherein said substrate is a porous support such as CSZ or alumina, and said ceramic film is an electrolyte, an interconnector, a fuel electrode or an air electrode of a solid oxide fuel cell. Type fuel cell.