Film formation method

Abstract

This film formation method is for forming a film for a hollow member. The hollow member is provided with a partition wall that has an outer surface and an inner surface, and has a plurality of holes that include a first opening that opens in the outer surface and a second opening that opens in the inner surface. The film formation method comprises: a first step for disposing a sealing member on the hollow member; a second step for decompressing the inside of the hollow member and bringing the sealing member into close contact with the outer surface of the hollow member; a third step for coating a film precursor onto a portion of the outer surface of the hollow member on which the sealing member in close contact is not located; and a fourth step for treating the coated film precursor and forming a film on the outer surface. The sealing member is more deformable than the hollow member and is disposed in the first opening and on an outer edge thereof.

Description

Film forming method

[0001] The present disclosure relates to a film formation method.

[0002] BACKGROUND ART There are various known methods for forming a film that can coat the surface of a substrate and impart desired properties to the surface.

[0003] Patent No. 6960556

[0004] A film-forming method according to one aspect of the embodiment is a film-forming method for a hollow member. The hollow member has a partition wall having an outer surface and an inner surface, and has a plurality of holes, each having a first opening opening on the outer surface and a second opening opening on the inner surface. The film-forming method includes a first step of placing a sealing member in the hollow member, a second step of reducing the pressure inside the hollow member and closely contacting the sealing member with the outer surface of the hollow member, a third step of applying a coating precursor to the outer surface of the hollow member where the closely contacted sealing member is not located, and a fourth step of treating the applied coating precursor to form a coating on the outer surface. The sealing member is more deformable than the hollow member and is placed on the outer surface at the first opening and its outer edge.

[0005] FIG. 1 is a diagram illustrating an example of a film formation method according to an embodiment. FIG. 2 is a flowchart illustrating an example of a film formation method according to an embodiment. FIG. 3 is a cross-sectional view illustrating an example of a first step. FIG. 4 is a cross-sectional view illustrating another example of a sealing member disposed in a hollow member. FIG. 5 is a cross-sectional view illustrating an example of a third step. FIG. 6 is a cross-sectional view illustrating an example of a fourth step. FIG. 7 is a perspective view illustrating an example of a film formed by the film formation method according to an embodiment. FIG. 8 is a cross-sectional view taken along line A-A in FIG. 7. FIG. 9 is an enlarged cross-sectional view of region B shown in FIG. 8. FIG. 10A is a cross-sectional view illustrating an example of a hole in a hollow member. FIG. 10B is a cross-sectional view illustrating another example of a hole in a hollow member. FIG. 10C is a cross-sectional view illustrating another example of a hole in a hollow member. FIG. 10D is a cross-sectional view illustrating another example of a hole in a hollow member. FIG. 10E is a cross-sectional view illustrating another example of a hole in a hollow member. FIG. 10F is a cross-sectional view illustrating another example of a hole in a hollow member. 10G and 10H are cross-sectional views showing other examples of holes in hollow members.

[0006] For example, it is possible to selectively coat a portion of the substrate by covering (masking) the portion where no coating is required with a tape member, etc. However, when the above-described film-forming method is applied to the outer surface of a hollow member having a plurality of holes, there is a concern that the coating liquid may penetrate into the interior of the hollow member through gaps in the tape member, and therefore there is room for improvement.

[0007] Therefore, it is desired to provide a film forming method that can coat the outer surface of a hollow member having a plurality of holes with high precision.

[0008] Hereinafter, embodiments of the film forming method disclosed in the present application will be described in detail with reference to the accompanying drawings. However, the present disclosure is not limited to the embodiments described below.

[0009] It should also be noted that the drawings are schematic and that the dimensional relationships and ratios of elements may differ from reality. Furthermore, the drawings may contain parts whose dimensional relationships and ratios differ from one another.

[0010] 1 is a diagram illustrating an example of a film formation method according to an embodiment. A hollow member 10, which is the target of film formation, has a partition wall 12 and a plurality of holes 16. The partition wall 12 is a partition that separates the inside of the hollow member 10 from the outside. The partition wall 12 has an outer surface 13 and an inner surface 14. The plurality of holes 16 are provided so as to penetrate the outer surface 13 and the inner surface 14, respectively.

[0011] According to the film forming method of this embodiment, it is possible to form a coated body 20 in which the coating 18 is located on the outer surface 13, but the coating 18 is not located in the plurality of holes 16 and the inner surface 14. The coated body 20 may have non-coated portions 200 in the outer surface 13 located at the plurality of holes 16 and their outer edges, where the coating 18 is not located.

[0012] Next, a film forming method according to an embodiment will be described in detail. Fig. 2 is a flowchart showing an example of the film forming method according to an embodiment. As shown in Fig. 2, in a first step, a sealing member 30 is placed on the outer surface 13 of the hollow member 10 (step S11). Hereinafter, the hollow member 10 with the sealing member 30 placed thereon may be referred to as a sealing body 40.

[0013] Fig. 3 is a cross-sectional view illustrating an example of the first step. As shown in Fig. 3, the hollow member 10 has a partition wall 12 and a plurality of holes 16. The partition wall 12 has an outer surface 13 and an inner surface 14. The partition wall 12 may be made of, for example, a metal or an alloy.

[0014] The partition wall 12 may be cylindrical. The hollow member 10 may have holes 12a and 12b as second holes located at both ends of the partition wall 12 in the longitudinal direction.

[0015] The holes 16 have a first opening 16 a and a second opening 16 b. The first opening 16 a opens to the outer surface 13. The second opening 16 b opens to the inner surface 14. The multiple holes 16 are through holes that connect the outer surface 13 side and the inner surface 14 side of the hollow member 10.

[0016] The sealing member 30 includes a sealing member 31 that covers the first opening 16a and the outer surface 13 located at the outer edge of the first opening 16a. The sealing member 31 has a first portion 31a facing the hole 16 and a second portion 31b facing the outer surface 13 located at the outer edge of the first opening 16a. The thickness of the first portion 31a may be different from the thickness of the second portion 31b. Specifically, the first portion 31a may be thicker than the second portion 31b. In other words, the first portion 31a may protrude into the hole 16. When the first portion 31a protrudes into the hole 16, the positioning of the sealing member 31 is facilitated. Furthermore, the coating liquid is less likely to penetrate into the partition walls 12 during the third step described below.

[0017] The sealing members 31 may be disposed on one hole 16 and the outer edge of the hole 16, or on two or more holes 16 and the outer edges of the holes 16 among the plurality of holes 16 in the hollow member 10. Disposing the sealing members 31 on two or more holes 16 and the outer edges of the holes 16 improves work efficiency compared to disposing the sealing members 31 on one hole 16 and the outer edge of the holes 16. Furthermore, one sealing member 31 may be disposed so as to cover the outer edges of all of the holes 16 and the holes 16 in the hollow member 10.

[0018] When the partition walls 12 have holes 12a, the sealing member 30 may include a sealing member 32 that covers the holes 12a and the outer surface 13 located on the outer edge of the holes 12a. The sealing member 32 has a first portion 32a facing the holes 12a and a second portion 32b facing the outer surface 13 located on the outer edge of the holes 12a. The thickness of the first portion 32a may be different from the thickness of the second portion 32b. Specifically, the second portion 32b may be thicker than the first portion 32a. This facilitates close contact between the hollow member 10 and the sealing member 32 in the second step described below, and makes it difficult for a coating liquid to penetrate into the partition walls 12 during the third step described below.

[0019] When the partition walls 12 have holes 12b, the sealing member 30 may include a sealing member 33 that covers the holes 12b and the outer surface 13 located at the outer edge of the holes 12b. The sealing member 33 has a first portion 33a facing the holes 12b and a second portion 33b facing the outer surface 13 located at the outer edge of the holes 12b. The thickness of the first portion 33a may be different from the thickness of the second portion 33b. Specifically, the second portion 33b may be thicker than the first portion 33a. This facilitates close contact between the hollow member 10 and the sealing member 33 in the second step described below, and makes it difficult for a coating liquid to penetrate into the partition walls 12 during the third step described below.

[0020] The sealing member 30 is more easily deformed than the hollow member 10. For example, the material of the sealing member 30 may have a lower elastic modulus than the material of the hollow member 10. The sealing member 30 may have a base material and a coating layer, with only the coating layer having a lower elastic modulus than the material of the hollow member 10. Furthermore, for example, when the material of the sealing member 30 is the same as the material of the hollow member 10, the thickness of the sealing member 30 may be smaller than the thickness of the hollow member 10 (partition wall 12). The material of the sealing member 30 may be a material that has high adhesion to the hollow member 10 in the second step described below and is strong enough to withstand the environment in the third step, i.e., chemical resistance and heat resistance. The material of the sealing member 30 may be, for example, a resin material such as a silicone resin, a fluororesin, or a polyimide resin, or a rubber material such as a silicone rubber or a fluororubber.

[0021] The sealing member 30 may also have an exhaust mechanism 35. The exhaust mechanism 35 has an exhaust valve. When an exhaust pump (not shown) is attached to the exhaust mechanism 35 and operated, the exhaust pump exhausts air from inside the hollow member 10, reducing the pressure inside the hollow member 10. The exhaust valve can maintain the internal pressure of the hollow member 10 even when the exhaust pump is removed.

[0022] The exhaust mechanism 35 may have a cover that prevents the coating liquid from adhering to the exhaust valve. The exhaust mechanism 35 may be provided in the sealing member 31, or in either the sealing member 32 or 33.

[0023] 4 is a cross-sectional view showing another example of a sealing member disposed in a hollow member. The sealing member 31 may have a columnar portion 31c, a first edge portion 31d, and a second edge portion 31e. The columnar portion 31c is a portion that penetrates the hole 16. The columnar portion 31c may be in contact with a wall surface 16c of the hole 16. The first edge portion 31d is a portion that extends from the columnar portion 31c along the outer surface 13 of the hole 16. The second edge portion 31e is a portion that extends from the columnar portion 31c along the outer edge of the hole 16 to the inner surface 14. As such, the sealing member 31 having the second edge portion 31e is less likely to fall off from the outer surface 13 where it is disposed, thereby improving work efficiency in the second step described below.

[0024] 2, further explanation will be given. In the second step, the pressure inside the hollow member 10 is reduced, and the sealing member 30 is brought into close contact with the outer surface 13 (step S12). For example, in FIG. 3, when an exhaust pump (not shown) is attached to the exhaust mechanism 35 and operated, the pressure inside the hollow member 10 is reduced, and the elastic sealing member 30 is brought into close contact with the outer surface 13, thereby maintaining the reduced pressure inside the hollow member 10.

[0025] Next, in a third step, a coating precursor is applied to the outer surface 13 of the hollow member 10 to which the sealing member 30 has been attached in the second step (step S13). Fig. 5 is a cross-sectional view illustrating an example of the third step. As shown in Fig. 5, the third step may include a step of immersing the sealing body 40, the inside of which has been decompressed, in a coating liquid 51 containing the coating precursor.

[0026] The coating liquid 51 contains a coating precursor that forms a coating through the fourth step described below. The coating liquid 51 may be a fluid in which the coating precursor is dissolved or dispersed in a solvent or the like. The combination of the coating precursor and the solvent contained in the coating liquid 51 can be selected depending on the type of coating. The coating liquid 51 may contain additives such as a dispersant and a stabilizer.

[0027] In the third step, a coating liquid 51 containing a coating precursor is applied to the outer surface 13 where the sealing member 30 is not located. The sealed body 40 may be immersed in the coating liquid 51 and removed from the coating liquid 51 by operating a hanger 50 attached to the sealed body 40. The hanger 50 may be, for example, a wire. The hanger 50 may be attached to the sealing members 32 and 33 shown in FIG. 3, or may be attached to the hollow member 10 covered with the sealing member 30. The hanger 50 may be integrated with the sealing member 30 in advance.

[0028] The material of hanger 50 may be, for example, a resin or a metal, as long as it has strength against coating liquid 51. Hanger 50 may also serve as a conductor for applying a voltage to hollow member 10, if necessary.

[0029] The third step may be, for example, any one of a dip coating method, a plating method, and an electrodeposition coating method.

[0030] Finally, in the fourth step, the coating precursor applied in the third step is treated to form a coating on the outer surface 13 (step S14). FIG. 6 is a cross-sectional view illustrating an example of the fourth step. As shown in FIG. 6, in the fourth step, a coated body 20 is obtained in which a coating 18 is formed on the outer surface 13 to which the coating liquid 51 has been applied. The treatment of the coating precursor may include, for example, a degreasing treatment, a drying treatment, and / or a heat treatment, and may also include an ultraviolet or other electron beam irradiation treatment. The fourth step may also include a step of removing the sealing member 30 from the hollow member 10 or the coated body 20. The step of removing the sealing member 30 may be performed, for example, before or after the treatment of the coating precursor. When the treatment of the coating precursor includes multiple steps, the step of removing the sealing member 30 may be performed between the multiple steps.

[0031] The coated body 20 has non-coated portions 200 where the coating 18 is not located on the outer surface 13 located at the plurality of holes 16 and the outer edges thereof. This allows the outer surface 13 of the hollow member 10 having the plurality of holes 16 to be coated with precision. The coated body 20 may also have non-coated portions 201, 202 where the coating 18 is not located on the outer surface 13 located at the holes 12a and the outer edges of the holes 12a, and on the outer surface 13 located at the holes 12b and the outer edges of the holes 12b. If necessary, post-processing may be performed to position the coating 18 on the non-coated portions 201, 202.

[0032] Fig. 7 is a perspective view showing an example of a film-formed body produced by the film-formation method according to the embodiment. Fig. 8 is a cross-sectional view taken along line A-A in Fig. 7. Fig. 9 is an enlarged cross-sectional view of region B shown in Fig. 8. The hollow member 10 of the film-formed body 20 has a first portion 121 having a hole 16, a second portion 122 facing the first portion 121 at a distance, and a third portion 123 connecting the first portion 121 and the second portion 122.

[0033] 7 may be made of a metal containing chromium, and the coating 18 may be made of an oxide containing at least one of zinc (Zn), manganese (Mn), cobalt (Co), cerium (Ce), copper (Cu), and nickel (Ni).

[0034] For example, as shown in Fig. 7, the coated body 20 has non-coated portions 200 where the coating 18 is not located on the outer surface 13 located at the plurality of holes 16 and the outer edges thereof. The coated body 20 also has non-coated portions 201, 202 where the coating 18 is not located on the outer surface 13 located at the holes 12a and the outer edges of the holes 12a, and on the outer surface 13 located at the holes 12b and the outer edges of the holes 12b. Note that Figs. 7 and 8 show an example in which the non-coated portion 200 is located on part of the outer surface 13 of the first portion 121, but the non-coated portion 200 may be located on the entire outer surface 13 of the first portion 121.

[0035] The thickness of coating 18 may decrease at the boundary with non-coated portion 200 as it approaches non-coated portion 200 or hole 16. In portions other than the boundary, coating 18 may have a thickness of, for example, 0.5 μm or more and 5 μm or less.

[0036] 10A is a cross-sectional view showing an example of a hole in a hollow member 16. As shown in FIG. 10A , the opening area of ​​the first opening 16 a, the opening area of ​​the second opening 16 b, and the cross-sectional area along the outer surface 13 of the hole 16 between the two openings may be approximately equal.

[0037] 10B to 10H are cross-sectional views showing other examples of holes in a hollow member. As shown in FIGS. 10B to 10F, the opening area of ​​at least one of first opening 16a and second opening 16b of hole 16 may be larger or smaller than the cross-sectional area along outer surface 13 of hole 16 between the two openings.

[0038] 10G, the cross-sectional area of ​​at least a portion of the hole 16 along the outer surface 13 between two openings may be smaller than the cross-sectional area of ​​the remaining portion. Also, as shown in FIG. 10H, the cross-sectional area of ​​at least a portion of the hole 16 along the outer surface 13 between two openings may be larger than the cross-sectional area of ​​the remaining portion. The hole 16 may have a shape that is an appropriate combination of the shapes shown in FIGS. 10B to 10H. The hole 16 may have a shape in which the cross-sectional area gradually decreases or increases from the first opening 16a to the second opening 16b. The central axis of the hole 16 may be aligned along the thickness direction of the partition wall 12, or may be inclined or curved relative to the thickness direction of the partition wall 12.

[0039] Such a film-formed body 20 can be used as an electrochemical cell by disposing an electrochemical element such as a fuel cell element, an electrolytic element, a co-electrolytic element, or a water splitting element in the non-film-formed portion 200 and circulating a reducing gas through the hollow portion.

[0040] Although the present disclosure has been described in detail above, the present disclosure is not limited to the above-described embodiments, and various modifications, improvements, etc. are possible within the scope that does not deviate from the gist of the present disclosure.

[0041] In one embodiment, (1) a film formation method is a film formation method for a hollow member, wherein the hollow member has a partition wall having an outer surface and an inner surface, and has a plurality of holes each having a first opening opening to the outer surface and a second opening opening to the inner surface, and includes the steps of: a first step of arranging a sealing member that is more easily deformed than the hollow member on the first opening and on the outer surface located at the outer edge of the first opening; a second step of reducing the pressure inside the hollow member and tightly fitting the sealing member to the outer edge; a third step of applying a coating precursor to the outer surface of the hollow member where the tightly fitted sealing member is not located; and a fourth step of treating the applied coating precursor to form a coating on the outer surface.

[0042] (2) In the film forming method (1) above, the partition wall may be made of a metal or an alloy.

[0043] Furthermore, (3) in the film forming method of (1) or (2) above, the sealing member may be disposed in two or more of the holes and on the outer edges of the two or more holes.

[0044] Furthermore, (4) in any one of the film-forming methods (1) to (3) above, the third step may include immersing the hollow member to which the sealing member is adhered in a coating liquid containing the coating precursor.

[0045] Furthermore, (5) in the film forming method of (4) above, the third step may be any one of a dip coating method, a plating method, and an electrodeposition coating method.

[0046] The disclosed embodiments should be considered in all respects as illustrative and not restrictive. Indeed, the above-described embodiments may be embodied in various forms. Furthermore, the above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

[0047] REFERENCE SIGNS LIST 10 hollow member 12 partition wall 13 outer surface 14 inner surface 16 hole 20 film-formed body 30 sealing member 40 sealing body

Claims

1. A method for forming a film on a hollow member, wherein the hollow member has a partition wall having an outer surface and an inner surface, and has a plurality of holes with a first opening opening on the outer surface and a second opening opening on the inner surface, the method comprising: a first step of arranging a sealing member that is more easily deformed than the hollow member on the first opening and on the outer surface located at the outer edge of the first opening; a second step of reducing the pressure inside the hollow member and tightly adhering the sealing member to the outer surface; a third step of applying a coating precursor to the outer surface of the hollow member where the tightly adhering sealing member is not located; and a fourth step of treating the applied coating precursor to form a coating on the outer surface.

2. The film forming method according to claim 1, wherein the partition wall is made of a metal or an alloy.

3. The film forming method according to claim 1 or 2, wherein the sealing member is disposed in two or more of the holes and on the outer edges of the two or more holes.

4. A film forming method according to any one of claims 1 to 3, wherein the third step includes immersing the hollow member to which the sealing member is adhered in a coating liquid containing the coating precursor.

5. The film forming method according to claim 4, wherein the third step is one of a dip coating method, a plating method, and an electrodeposition coating method.

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