JP2000030720A - Manufacture of lcm dense film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of an LCM dense film with high productivity and low cost by specifying the composition of powder included in slurry, calcination condition, and mixing ratio (a ratio of coarse powder to fine powder), and manufacturing in a wet process. SOLUTION: In the manufacturing method of an lanthanum calcium manganite(LCM) dense film on a porous substrate, a film is formed on a film forming surface with two kinds of slurry containing a film material having relatively large particle size (coarse powder slurry) and slurry containing relatively small particle size (fine powder slurry), then baked to form the film. Gas permeability flux Q of the LCM is specified to 1<=50 (m3/m2.hr.atm).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a Ca-doped plan chromite interconnector for a solid oxide fuel cell (hereinafter referred to as SOFC) and an intermediate layer (hereinafter referred to as a pre-coat layer) of an air electrode. Method for producing sintered film requiring denseness and SOFC by single firing
Having the same degree of denseness as the interconnector film for
The present invention relates to a method for producing a CM dense film.

[0002]

2. Description of the Related Art A conventional dense film of lanthanum manganite has been produced by a CVD method. Although this method is suitable for producing a dense film, it is necessary to perform the film formation under a special atmosphere / physical condition shielded from the atmosphere, which requires expensive equipment and large members. It is difficult to form a film on the surface, the productivity is low, and the cost is high.
For this reason, there is a wet method as a method which is excellent in productivity and can be produced at low cost. However, when a film is formed by the wet method, it is difficult to form a dense LCM film.

[0003]

Although the CVD method is suitable for producing a dense film, it is necessary to perform the film formation under a special atmosphere and physical conditions, which are isolated from the atmosphere. And it is difficult to apply a film to a large-sized member, the productivity is low, and the cost is high. For this reason, there is a wet method as a method which is excellent in productivity and can be produced at low cost. However, when a film is formed by the wet method, it is difficult to form a dense LCM film.

[0004] The present invention solves the above-mentioned problems of the prior art, and examines the composition of powder contained in a slurry, the conditions of calcination, and the mixing ratio (ratio of coarse powder to fine powder). An object of the present invention is to provide a method for producing an LCM dense film by a method, which is excellent in productivity and low in cost.

[0005]

Means for Solving the Problems and Actions / Effects of the Invention According to the present invention made to solve the above problems, a dense sintered film of lanthanum calcium manganite (hereinafter referred to as LCM) is formed on a porous substrate. In the method, a film is formed on the film forming surface using two types of a slurry containing a film material having a relatively large particle size (coarse powder slurry) and a slurry containing a film material having a relatively small particle size (fine powder slurry); Further firing,
It was decided to produce a film.

A method of forming a film by using two types of slurries, a coarse powder slurry containing a film substance having a relatively large particle diameter and a fine powder slurry containing a film substance having a relatively small particle diameter, and performing film formation and baking. As a result, firing and peeling of the film do not occur.

[0007]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, film formation and baking are performed using two types of slurries, a coarse powder slurry containing a film substance having a relatively large particle diameter and a fine powder slurry containing a film substance having a relatively small particle diameter. However, it is difficult to obtain a dense film using only the coarse powder slurry because the sinterability of the powder is low. This is because the shrinkage is too large, so that baking, peeling of the film, and the like are likely to occur.

In the present invention, when the dense LCM membrane is used as a precoat layer for a solid oxide fuel cell, the gas permeation flux Q1 ≦ 50 (m ³ / m ² · h) of the dense LCM membrane is used.
r.atm). This is because Q1
If ≦ 50 (m ³ / m ² · hr · atm), the gas permeation flux Q3 ≦ 0.
This is because it can be set to 01 (m ³ / m ² · hr · atm). In addition, the gas permeability of the interconnector film becomes better as the gas permeability of the precoat layer becomes smaller, so that the denser the precoat layer is, the better.

The gas permeation flux Q1 ≦ 50 in the present invention.
When preparing an LCM dense film of (m ³ / m ² · hr · atm), a coarse powder composition (La _1-X1 Ca _X1 ) _Y1 MnO ₃ fine powder composition (La _1-X2 Ca _X2 ) _Y2 MnO ₃ , 0 <X
1 ≦ X2 ≦ 0.4, 0.9 ≦ Y1 ≦ 1, 0.9 ≦ Y2 ≦
It is preferably in the range of 1. The reason for this is that it is difficult to produce a dense film without containing Ca at all. On the other hand, if it is larger than 0.4, the sinterability is too high, which may cause the film to peel or cut off. Because there is.

For Y1 and Y2, when Y <0.9, the manganese component is easily released and diffused, and when used in SOFC, the performance of other materials may be reduced.
When Y> 1, it reacts with YSZ used for the electrolyte of the SOFC, generates La ₂ Zr ₂ O _7, and may significantly reduce the performance of the SOFC.

The gas permeation flux Q1 ≦ 50 in the present invention.
(M ³ / m ² · hr · atm) In producing an LCM dense film, the calcining temperature of the coarse powder used for the slurry is set to T1.
Assuming that the calcination temperature of the fine powder is T2, it is preferable that T1 ≧ T2. The reason is that when the calcination temperature of the fine powder is higher, the role of the fine powder as a sintering aid is reduced, and it becomes difficult to produce a dense film.

In the case where the LCM dense membrane is used as a gas separation membrane, the gas permeation flux Q2 ≦ 0.0 of the LCM dense membrane is used.
It is preferably 1 (m ³ / m ² · hr · atm).
The reason for this is that the gas permeation flux Q2 ≦ 0.01 (m ³
/ M ² · hr · atm) has sufficient gas tightness as a film for separating gas.

In the present invention, the gas permeation flux Q2 ≦ 0.0
In preparing an LCM dense film of 1 (m ³ / m ² · hr · atm), a coarse powder composition (La _{1 -X3} Ca _X3 ) _Y3 MnO ₃ fine powder composition (La _{1 -X4} Ca _X4 ) _Y4 MnO ₃ was used. If 0.
1 ≦ X3 ≦ X4 ≦ 0.4, 0.9 ≦ Y3 ≦ 1, 0.9 ≦
It is preferable that Y4 ≦ 1.

[0014] The reason is as follows.
As shown by the relationship between the coarse powder and the fine powder and the gas permeation flux in FIG. 3, it is difficult to obtain a dense film of Q2 ≦ 0.01 (m ³ / m ² · hr · atm), and X> 0. .4, the sinterability is too high, which may cause the film to burn off, peel off, etc. Table 1 of Example 1 for such reasons.
From FIG. 3 and FIG. 3, it is more preferable that 0.2 ≦ X1 ≦ X2 ≦ 0.35.

[0015]

[Table 1]

As for Y3 and Y4, when Y <0.9, the manganese component is easily released and diffused, and the durability of the material may be significantly reduced. This is because it is difficult to produce a dense film because of the lowering.

In the present invention, if the calcination temperature of the coarse powder used for the slurry is T3 and the calcination temperature of the fine powder is T4, it is preferable that 200 ° C. ≦ (T3-T4) ≦ 600 ° C. . This is because the relationship between the calcining temperature of the powder and the gas permeation flux in Table 2 and the relationship between the calcining temperature difference and the gas permeation flux in FIG.
If the temperature exceeds 00 ° C., the denseness is significantly reduced. As shown in Table 2 and FIG. 4, since the gas permeation flux is the smallest in the range of 300 to 500 ° C., 300 ° C. ≦ (T
More preferably, 1-T2) ≦ 500 ° C.

[0018]

[Table 2]

In the present invention, when the amount of coarse powder used for the coarse powder slurry is Ag and the amount of fine powder is B g, the ratio between the amount of coarse powder and the amount of fine powder is 0.1 ≦ B / (A +
B) It is preferred that ≦ 0.5. The reason for this is that if B / (A + B) <0.1, it is difficult to obtain a dense film due to a small amount of fine powder, and B / (A + B)>
When the ratio is 0.5, the amount of fine powder is too large and the sinterability is too high, so that the film is liable to be cut off and peeled off.

The method for producing the slurry particles of the present invention is not limited to a specific method. Spray drying, evaporation to dryness, spray pyrolysis, coprecipitation and the like can be used. The method of adjusting the particle size can be determined by classification after pulverization. The content of the ceramic particles in the slurry is 10 parts to 15 parts per 100 parts of the slurry solution.
0 parts is preferred.

In the present invention, the density of the LCM dense film is preferably 50 (m ³ / m ² · hr · atm) or less when used as an intermediate layer such as a precoat layer for SOFC. When used as a dense film of LCM, it is 0.01 (m ³ / m ² · hr · atm) or less, more preferably 0.0001 (m ³ / m ² · hr · atm).
The following is preferred.

The composition of the slurry solution of the slurry of the present invention is not particularly limited. The slurry solution contains a solvent,
It may contain a binder, a dispersant, an antifoaming agent, and the like. However, a non-volatile solvent is used as a solvent,
It is preferable to contain 80 wt%. More preferably, 1
5 to 40% by weight. The action of the hardly volatile solvent suppresses a change in viscosity of the slurry during preparation and storage of the slurry, and also suppresses generation of cracks due to drying after film formation (for example, dipping) using the slurry. That is. Here, the degree of refractoryness is desirably 1 or less, for example, when the degree of butyl acetate is 100.

As an example of the non-volatile solvent, there can be mentioned α-terpineol. Content of non-volatile solvent is 1
The reason why 0 to 80 wt% is preferable is that low concentration (10 wt%
If the concentration is less than 80 wt%, the dispersibility of the powder becomes poor. The content of the hardly sinterable solvent is more preferably 15 to 40 wt%. This is because, within this range, the dispersibility of the powder in the slurry and the drying condition after dipping can be most balanced.

The slurry solution may contain a general volatile solvent other than the hardly sinterable solvent. The action of the solvent contained in the solution is to improve the dispersibility of the powder and the defoaming property. As an example of such a solvent, ethanol is suitable. Its preferable content is the solvent 1 of the slurry solution.
20 to 90 parts by weight based on 00 parts by weight.

The function of the binder contained in the slurry solution is to improve the coating property (adhesion) of the powder on the substrate. The amount of the binder is preferably 0.1 to 10 parts based on 100 parts of the solvent. The reason is that if the concentration is low (less than 0.1 wt%), the coating property is low, and if the concentration is high (exceeding 10 wt%), the dispersibility of the powder becomes poor. As a specific example of the binder, ethyl cellulose is suitable.

The action of the dispersant contained in the slurry solution is as follows:
This is an improvement in the dispersibility of the powder. The amount of dispersant is 100
0.1 to 4 parts per part is preferred. The reason is that when the concentration is low (less than 0.1 wt%), the dispersibility is low, and when the concentration is high (4 wt%).
This is because, if it exceeds 0.1% by weight, the slurry tends to be denatured. Specific examples of dispersants include polyoxyethylene alkyl esters.

The antifoaming agent contained in the slurry solution has the function of eliminating bubbles in the slurry. The amount of the defoamer is 100
0.1 to 4 parts per part is preferred. The reason is that if it is less than this, the effect is not so expected, and if it exceeds that, the binder in the slurry tends to be denatured. Specific examples of the antifoaming agent include sorbitan sesquioleate.

An embodiment of the present invention will be described below. Example 1: Preparation of LCM dense film (1) Synthesis of LCM powder FIG. 1 shows a method of synthesizing LCM powder. La (NO ₃ ) ₃ a
q, Ca (NO ₃ ) ₂ .4H ₂ O, and Mn (NO ₃ ) ₂ aq are mixed so as to have a predetermined composition ratio, and La, Ca, M
A nitrate aqueous solution containing n was prepared. The oxide content at this time was set to 20 wt%.

A separately prepared oxalic acid aqueous solution (the amount of oxalic acid was 1.05 times the stoichiometric ratio with respect to La, Ca and Mn) was added to the above aqueous nitrate solution and stirred for about 5 hours. After stirring, the mixture was dried at 120 ° C. in order to remove moisture, and further thermally decomposed at 500 ° C. for 5 hours to remove a nitric acid component and residual oxalic acid. Further, after the pyrolyzed powder was calcined, it was pulverized and classified so as to have a predetermined particle size to obtain a slurry powder.

(2) Aqueous slurry solution After mixing 33 parts of α-terpineol and 100 parts of ethanol, ethyl cellulose as a binder was mixed with 1.
2 parts, 1 part of polyoxyethylene alkyl phosphate as a dispersant, and 1 part of sorbitan sesquioleate as an antifoaming agent were added and mixed to obtain a slurry solution.

(3) Preparation of Coarse Powder Slurry 100 parts of the above slurry solution was controlled to an average diameter of 2 μm.
I controlled (La_1-X3Ca _X3)_0.99MnO_ThreeComposition coarse powder 40
And the average diameter was controlled to 0.5 μm (La_1-X4Ca_X4)
_0.99MnO_ThreeMix 10 parts of fine powder of the composition
Was prepared.

(4) Preparation of Fine Powder Slurry Fine powder 2 of (La _1-X4 Ca _X4 ) _0.99 MnO ₃ composition controlled to an average diameter of 0.5 μm with respect to 100 parts of the above slurry solution.
0 parts were mixed to prepare a fine powder slurry.

(5) Film-forming method (La _1-X3 Ca _X3 ) _0.99 MnO controlled to an average diameter of 2 μm
The coarse powder of _three compositions and the average diameter were controlled to 0.5 μm (La _1-X4
Ca _X4) to prepare a coarse particle slurry and fines slurry using a fine powder of _.99 MnO ₃ composition, by dipping the at film formation conditions shown in Table _{3 (La 0.8 Sr 0 .2)} 0.99 MnO 3 porous substrate The film was formed and baked at 1400 ° C. for 10 hours.

[0034]

[Table 3]

(6) Film Forming Method An outline of the slurry coating apparatus will be described with reference to FIG. The dipping apparatus 1 shown in FIG.
It comprises a pressure reducing device 3 and a pressurizing device 4. The dip tank 2 has an oblong tank 5 having a relatively shallow depth. A lid 6 is detachably mounted on the tank 5. Between the tank 5 and the lid 6, means (such as packing) for ensuring airtightness in the dip tank 2 is provided. In the dip tank 2, the slurry 7 is filled to a certain level.

A base 10 is laid on the bottom 8 of the dip tank 2 via two tables 9 on the left and right sides. The base 10 has a cylindrical shape with a bottom, and the left end is a bottom 11.
The right end is the opening end 12. The open end 13 is covered with a stopper 14. An exhaust tube 15 is inserted into the center of the stopper 14. The exhaust tube 15 is connected to an exhaust pump 17 via an exhaust line 16.
(Vacuum pump). When the exhaust pump 17 is operated, the air in the substrate 10 is exhausted from the exhaust port 18 on the exit side of the pump 17 through the exhaust tube 15 and the exhaust pipe 16, and the inside of the substrate 10 is depressurized.

The pressurizing device 19 comprises a pressurizing tube 20, a valve 21, and a gas cylinder 22. When the valve 21 is opened, N2 gas is sent from the gas cylinder 2 into the dip tank 2 through the pressurizing tube 20, and pressurizes the dip tank. The lid 6, the pressure tube 20 and the exhaust pipe 1
6 is sealed by a suitable means.

Using such a dipping apparatus 1, the substrate 10 can be subjected to slurry coating or application of a gas differential pressure (to be performed with the slurry 7 removed) under various pressure conditions. The substrate 10 shown in this figure is a cell of a cylindrical solid electrolyte fuel cell. Slurry coating cannot be performed on the portions that come into contact with the mounting tables 9 and 9 ′, but there is no problem if the position is set as the non-film forming section. Further, the pressurizing device may be of a vertical type, and the base tube is held by the main body. In this case, when the base tube is placed in the container, the placing tables 9 and 9 'become unnecessary, and a film can be formed on the entire surface.

(7) Examination of the composition of the powder The composition of the coarse powder (La _{1 -X3} Ca _X3 ) _0.99 MnO ₃ , which is a powder having a relatively large particle diameter, composition _{(La 1-X4 Ca X4)} 0.9 9 Mn
When the composition was O _{3, the} composition conditions were examined under the conditions shown in Table 1. As a result, when X3 is less than 0.1, the value of the gas permeation flux is larger than 0.01 m ³ / m ² · hr · atm. It can be seen that a dense film having a value of 0.01 m ³ / m ² · hr · atm or less was obtained. In addition, although the tendency that the denseness is improved is recognized up to X4 = 0.35, X4 ≧ 0.35
It can be seen that the tendency to reduce the denseness is observed when the value becomes. From this viewpoint, 0.2 ≦ X3 ≦ X4 ≦ 0.35 is more preferable.

(8) Examination of the ratio of powder Both the composition of the coarse powder and the composition of the fine powder were (La _0.7 Ca _0.3 ) _0.99
As MnO ₃ , the amount of coarse powder in the coarse powder slurry used for film formation was A, and the amount of fine powder was B, and the proportion of the powder was adjusted to prepare a slurry, which was then fired. Incidentally, the fine powder slurry was prepared under the same conditions as those for preparing the fine powder slurry shown in (4).

As a result, when B / (A + B) <0.1 and B / (A + B)> 0.5, the value of the gas permeation flux becomes
It became larger than 0.01 m ³ / m ² · hr · atm,
When 0.1 ≦ B / (A + B) ≦ 0.5, the value of the gas permeation flux was 0.01 m ³ / m ² · hr · atm or less, and it was confirmed that a dense film could be produced. B / (A + B) = 0.6
As a result, burnout was confirmed on the film surface.

Since the gas permeation flux changes when the film forming conditions are changed, even when used as a precoat layer,
It is preferable that 0.1 ≦ B / (A + B) ≦ 0.5.

(9) Examination of Calcination Temperature of Powder Both the coarse powder and the fine powder have the composition of (La _0.7 Ca _0.3 ) _0.99
A slurry was prepared using MnO ₃ powder having the calcining temperature under the conditions shown in Table 2, and the film was fired. As a result, when the difference between the calcining temperatures was 100 ° C. and 700 ° C., the value of the gas permeation flux was larger than 0.01 m ³ / m ² · hr · atm, and a dense film was not obtained. ~ 600 ° C
, A gas permeation flux value of 0.01 m ³ / m ²
It was confirmed that a dense film can be produced at a value of hr.atm or less. Further, as shown in FIG.
When the temperature is from 00 ° C. to 500 ° C., the gas permeation flux becomes extremely small, and a dense film can be produced.
More preferable conditions are 0 ° C to 500 ° C.

Example 2 Preparation of SOFC Interconnector Film (1) Formation of Precoat Layer La _0.8 Sr _0.2 MnO ₃ (Gas flux: 2000 (m ^{3)
/ M 2 · hr · atm)} ) La 0.8 on a porous substrate Ca
_{A 0.2} MnO ₃ film was formed and fired using the same coarse powder slurry and fine powder slurry as in Example 1, and the gas permeation flux was 0.01 to 1
A film of 00 (m ³ / m ² · hr · atm) was produced. The value of gas permeation was controlled by changing the film forming conditions.

(2) Preparation of interconnector film Alumina powder was sprayed on the La _0.8 Ca _0.2 MnO ₃ film by spraying to roughen the surface, and then a La _0.8 Ca _0.2 CrO ₃ film was formed on the film surface. Deposited at 1400 ° C for 1
The keep was baked for 0 hours.

[0046] _{(3) La 0.8 Ca 0.2 CrO} 3 powder manufacturing method La _0.8 Ca _0.2 CrO ₃ become as La, Ca, Cr
Was prepared and a powder was prepared by a spray pyrolysis method. The produced powder was further calcined and subjected to a particle size control step to obtain a slurry powder.

(4) Preparation of slurry solution for La _0.8 Ca _0.2 CrO ₃ After mixing 33 parts of terpineol and 100 parts of ethanol, 1.2 parts of ethyl cellulose was used as a binder.
A slurry aqueous solution was prepared by adding and mixing 1 part of polyoxyethylene alkyl phosphate as a dispersant and 1 part of sorbitan sesquioleate as a defoaming agent.

(5) Preparation of Slurry An average diameter of 1 to 2 μm was added to 100 parts by weight of the slurry solution.
A slurry was prepared by mixing 40 parts of La _0.8 Ca _0.2 CrO ₃ powder controlled to m and 10 parts of La _0.8 Ca _0.2 CrO ₃ powder controlled to an average diameter of 0.5 μm.

(6) Film Forming Method The slurry was placed in the container shown in FIG. 2, and the sample was immersed in the slurry for 30 seconds. After removing the sample,
After being held for 0 minutes, it was further dried at 100 ° C. for 1 hour. This dipping and drying process was repeated five times. In Table 4, "no pressure reduction" refers to a film forming method in which the sample is immersed in the slurry as it is, and "3 kgf / cm ^{2 of the} reduced pressure slurry in the tube means that the sample is immersed in the slurry while the inside of the tube is evacuated. 3 from outside
In this method, a pressure difference of kgf / cm ² is applied to form a film.

[0050]

[Table 4]

(7) Results of gas permeation flux of interconnector membrane FIG. 5 shows the relationship between gas permeation flux (Q1) of the precoat layer and gas permeation flux (Q3) of the interconnector membrane. The gas permeability of the interconnector membrane tended to be lower as the gas permeability of the precoat layer was lower. Further, the gas permeation flux of the precoat layer is 50 (m ³ / m ² · hr · at
m) or less, the gas permeation flux of the interconnector membrane was found to be 0.01 (m ³ / m ² · hr · atm) or less, indicating that a favorable gas permeability for the interconnector membrane could be secured. .

[0052]

According to the present invention as described above,
An extremely dense LCM thin film can be manufactured by a wet method which is a relatively simple and inexpensive film forming method. When the LCM dense membrane is used as an intermediate layer between the air electrode of the SOFC and the interconnector, the diffusion of calcium chromate, which is a sintering aid for calcium doptolan chromite used for the interconnector material, can be suppressed. There is an effect that a connector film can be manufactured.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a method for synthesizing an LCM powder according to one embodiment of the present invention.

FIG. 2 is a diagram illustrating a slurry coating apparatus according to one embodiment of the present invention.

FIG. 3 is a view for explaining the relationship between the composition of coarse powder and fine powder and the gas permeation flux under the conditions shown in Table 1 of the present invention.

FIG. 4 is a diagram for explaining the relationship between the calcining temperature difference and the gas permeation flux according to the present invention.

FIG. 5 is a view for explaining the relationship between the gas permeation flux of the precoat layer and the interconnector membrane of the present invention.

DESCRIPTION OF SYMBOLS 1 Dipping device 2 Dipping tank 3 Decompression device 4 Pressurizing device 5 Tank 6 Lid 7 Slurry 8 Tank bottom 9 units 10 Base 11 Bottom 12 Open end 14 Plug 15 Exhaust tube 16 Exhaust line 17 Exhaust pump 18 Exhaust Mouth 20 Pressurized tube 21 Valve 22 Gas cylinder

Claims (9)

[Claims] In a method for producing a dense sintered lanthanum calcium manganite (hereinafter referred to as LCM) film on a porous substrate, a slurry (coarse powder) containing a film material having a relatively large particle diameter on the film formation surface is provided. A method for producing an LCM dense film, comprising: forming a film using two types of slurry including a film material having a relatively small particle diameter (fine slurry); 2. A method for producing an LCM dense membrane on a porous substrate, comprising the steps of:
The LC according to claim 1, which is (m ³ / m ² · hr · atm).
Method for producing M dense film. 3. Coarse powder composition (La _1-X1 Ca _X1 ) _Y1 Mn
O ₃ , fine powder composition (La _{1 -X 2} Ca _X2 ) _{Y 2} MnO ₃ , 0 <X1 ≦ X2 ≦ 0.4, 0.9 ≦ Y1 ≦ 1, 0.
3. The method for producing a dense LCM film according to claim 2, wherein 9 ≦ Y2 ≦ 1. 4. When the calcination temperature of the coarse powder used for the slurry is T1 and the calcination temperature of the fine powder is T2, T1 ≧ T
4. The method for producing a dense LCM film according to claim 2, wherein there is a relationship of 2. 5. A method for producing an LCM dense membrane on a porous substrate, comprising the steps of:
^2. L according to claim 1, wherein the value of L is 1 (m ³ / m ² · hr · atm).
A method for producing a dense CM film. 6. Coarse powder composition (La _{1 -X3} Ca _X3 ) _Y3 Mn
O ₃ , fine powder composition (La _{1 -X 4} Ca _X4 ) _{Y 4} MnO ₃ , 0.1 ≦ X3 ≦ X4 ≦ 0.4, 0.9 ≦ Y3 ≦ 1,
6. The method for producing a dense LCM film according to claim 5, wherein the range is 0.9 ≦ Y4 ≦ 1. 7. When X3 and X4 are 0.2 ≦ X3 ≦ X4 ≦
7. The LCM according to claim 6, wherein the LCM is 0.35.
How to make a dense film. 8. When the calcination temperature of the coarse powder used for the slurry is T3 and the calcination temperature of the fine powder is T4,
8. The method of manufacturing a dense LCM film according to claim 5, wherein a relationship of ≦ (T3−T4) ≦ 600 ° C. is satisfied. 9. 9. The amount of coarse powder used for the coarse powder slurry is Ag.
Wherein, when the amount of the fine powder is Bg, there is a relationship of 0.1 ≦ B / (A + B) ≦ 0.5 between the ratio of the amount of the coarse powder and the amount of the fine powder. A method for producing the LCM dense film according to the above.