JP2001246317A - Method for manufacturing coated metallic sheet, coated metallic sheet and electrical connecting member using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a coated metallic sheet which flattens the apexes of the projecting parts coated with a coating film of the coated metallic sheet formed by applying a coating material on a metallic sheet formed with the projecting parts, the metallic sheet which is flat in the apexes of the projecting parts coated with the coating material and an electrical connecting member consisting of the coated metallic sheet which is flat in the apexes of the projecting parts and has low contact resistance. SOLUTION: This method for manufacturing the coated metallic sheet consists in forming a plurality of the projecting parts on a metallic sheet, applying a coating material thereon and pressurizing the flat sheet by using a pressurizing means or pressurizing the roller at the apexes of the projecting parts to flatly mold the coating film in the state of drying and half curing the coating material or forming recessed parts at the apexes of the projecting parts and applying the coating material thereon, thereby flatly molding the coating film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of applying a coated metal plate, particularly a conductive paint, to a metal plate having a convex portion.
The present invention relates to a method for manufacturing a coated metal plate having excellent low contact resistance when used as an electrical connection member, a coated metal plate, an electrical connection member using the same, and a gas separator for a fuel cell.

[0002]

2. Description of the Related Art Conventionally, a combination of carbon and carbon has been used as a connection member such as a terminal for making an electrical connection from the viewpoint of conductivity and corrosion resistance. However, since the combination of carbon and carbon is expensive, a member made of a combination of carbon and a metal plate, which is inexpensive and has the same conductivity as carbon, specifically a carbon layer obtained by applying a paint containing carbon to a metal plate Are being studied. These connection members are usually used by cutting a flat plate-shaped member into a predetermined shape and further processing the same, but a carbon layer is provided on a metal plate having a plurality of protrusions, and only the protrusions are contacted. There is also a use to make it. In this case, in order to minimize the contact resistance, it is necessary to increase the contact area of the projection as much as possible. In order to obtain a connection member in which a carbon layer is provided on a metal plate having a convex portion, after providing a carbon layer on a flat metal plate, there is also a method in which a convex portion is formed using a press or the like. The carbon layer often peels off and is not practical. There is also a method in which a carbon-containing paint is applied to a metal plate on which convex portions have been formed in advance to form a carbon layer.
FIGS. 7 and 8 show side cross-sections (cross-sections viewed from the side,
Even if the convex portion 2 is provided so that the top 3 of the metal plate 1 is flat as shown in a side cross section, the area of the top 3 is extremely small, but the viscosity of the paint is large. The coating film that has flowed down from the end of the top 3 to the recess 8 between the protrusions and dried and solidified does not become flat, but the center of the top 3 becomes thicker and the end becomes thinner from the end to the center of the top 3 of the protrusion 2. The contact area of the top 3 on which the coating 5 is formed is smaller than the contact area of the top 3 on the metal plate 1 on which the coating 5 is not formed, and the contact resistance cannot be reduced. .

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks and to solve the above-mentioned drawbacks by applying a coating on a metal plate having a convex portion formed thereon. Providing a method of manufacturing a painted metal sheet having a flat top,
And to provide a coated metal plate having a flat top portion of the convex portion coated with the coating film, and further to provide an electrical connection member made of a coated metal plate having a flat top portion of the convex portion and low contact resistance. Aim.

[0004]

According to a method of manufacturing a coated metal plate of the present invention, a plurality of projections are formed on a metal plate, a coating material is applied thereon, and the metal plate is dried and semi-cured. Pressing a flat plate or a roller on the top of the convex part using means to form a coating film flat, or forming a concave part on the top of the convex part and applying paint on it to flatten the coating film It was molded. In addition, the method for producing a coated metal plate of the present invention includes:
Steps in which a plurality of convex portions are formed on a metal plate, then a lower layer is plated with Ni and an upper layer is plated with two layers consisting of Sn plating, and a paint is applied on a diffusion layer formed by thermal diffusion treatment. A two-layer plating of Ni plating on the lower layer and Sn plating on the upper layer, and then forming a plurality of projections on a metal plate having a diffusion layer formed by thermal diffusion treatment, and applying a paint thereon. A metal plate is formed by applying a two-layer plating consisting of Ni plating on the lower layer and Sn plating on the upper layer, forming a plurality of convex portions, and then applying a coating material thereon after subjecting the two-layer plating layer to thermal diffusion treatment. Can be adopted.

Hereinafter, preferred embodiments of the present invention will be described.
List the feature points. B) In these manufacturing methods, it is preferable that the side surfaces of the plurality of projections have a rectangular or trapezoidal shape, and that the projections have the same height. B) The cross section of the convex portion having the concave portion at the top provided with the plurality is substantially rectangular or trapezoidal with the upper side curved downward, and the highest portion of each convex portion has the same height. Is preferred. C) The coated metal plate of the present invention is manufactured by the above-described manufacturing method of the present invention, and is a coated metal plate having a flat top portion of the convex portion. D) In the coated metal plate of the present invention, it is preferable that the side cross section of the projection is rectangular or trapezoidal, and that the projections coated with the coating have the same height. E) The coated metal plate of the present invention is a coated metal plate in which a coating is coated on a metal plate in which a plurality of projections having a recess at the top are formed. Is characterized in that its upper surface is flat. F) In the coated metal plate of the present invention, the side cross section of the convex portion having the concave portion at the top is substantially rectangular or trapezoidal with the upper side curved downward, and the maximum of each convex portion coated with the coating film is the highest. The parts preferably have the same height. G) In any of the coated metal sheets of the present invention, the metal sheet is a stainless steel sheet having a lower layer plated with Ni and an upper layer plated with Sn, and having a diffusion layer formed by thermal diffusion treatment. Is preferred. H) Also, if the stainless steel plate is made of Fe—Cr or Fe—
It is preferably a Ni-Cr stainless steel sheet. I) Further, the coating film is preferably a coating film containing carbon black or graphite, an organic resin, and a crosslinking agent for the organic resin. D) The organic resin is preferably at least one of an acrylic resin, a polyester resin, a urethane resin and a phenol resin. And the electrical connection member of the present invention uses the above-mentioned coated metal plate for the electrical connection portion,
It is a coated metal plate with low contact resistance. Ii) Further, the gas separator for a fuel cell according to the present invention is an electrical connection member having low contact resistance by using any of the above-described coated metal plates.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a plurality of convex portions are formed on a metal plate, a paint is applied thereon, and the metal plate is dried and semi-cured. Pressing with a flat plate or a roller to form a flat shape, or forming a plurality of convex portions having a concave portion on the top of a metal plate, applying a coating material thereon, drying and curing to form a flat top portion flat A method of manufacturing a coated metal plate is used. Further, the former processing may be performed after the latter configuration is adopted. Ni plating and Sn plating are applied to the surface of a metal plate such as stainless steel,
By forming a diffusion layer by heat diffusion treatment, and applying an organic resin containing carbon black or graphite to the stainless steel plate provided with the above-mentioned convex portion, by forming a coated metal plate having a flat top portion of the convex portion, A coated metal plate with reduced contact resistance was obtained. Hereinafter, embodiments of the present invention will be described in more detail.

As a metal plate for a connection terminal of a battery, a normal steel plate or a surface-treated steel plate obtained by subjecting a steel plate to a surface treatment such as plating can be used. Preferably, a stainless steel plate is used. Examples of stainless steel sheets include Fe-Cr based martensite or ferrite, austenitic based, austenitic ferrite based, Fe-Ni based martensite based or semi-austenite based.
A Cr-based stainless steel plate can be used. Using Ni as a base plating on a stainless steel plate, Sn plating is performed on the Ni base plating layer, and then a diffusion layer is formed by performing a thermal diffusion process. A stainless steel plate having this diffusion layer uses a stainless steel plate as a base plate, and further has a diffusion layer mainly composed of a Ni—Sn alloy having excellent chemical resistance on its surface layer. It can be suitably used as a connection terminal of a fuel cell, particularly as a gas separator for a fuel cell which requires severe corrosion resistance.

[0008] Undercoating when forming a surface treatment layer and
Known Ni plating, electroless plating, electroless
Can be formed using any of the plating methods
You. In addition, Sn plating formed thereon is also well-known in the art.
It can be formed using either the electroplating method or the electroless plating method.
Can be achieved. The plating amount is Ni plating
The sum of the amount of Sn plating and the amount of Sn plating is 0.3 to 100 g / m.²Suitable
That's right. 0.3 g / m ²If less, heat diffusion after plating
Cr, which is a component of stainless steel sheet,
It is preferable because it diffuses into the layer and the conductivity is significantly reduced.
I don't. 100g / m²If it exceeds, it will be less economical
Is not preferred. Ni plating amount and Sn plating amount
The ratio is not particularly limited, but the corrosion resistance of the plating layer
From the point, the amount of Sn plating: 1 and the amount of Ni plating: 2 or more
Is particularly preferred. Thermal diffusion treatment contains oxygen
There is no nitrogen gas, hydrogen gas, mixed gas of nitrogen and hydrogen,
Or in an argon gas atmosphere, and the heating temperature range is 400
The temperature is preferably in the range of -700 ° C. Heating time
In addition, the cause of Cr or red rust
5 minutes to 6 hours within the range in which Fe does not diffuse to the surface
Is preferred.

In the present invention, a plurality of projections are formed on the surface of a metal plate such as a surface-treated stainless steel plate obtained as described above. As for the shape of the convex part, after forming a plurality of convex parts, coat the coating on it, and then press the flat plate or roller to flatten the convex part top part, the side cross section Is preferably a rectangular shape as shown in FIG. 1 or a trapezoidal shape as shown in FIG. After the coating film 5 is coated, a plurality of convex portions 2 having the concave portion 4 on the top 3 are formed so that the coating film surface becomes flat, and then the coating film is coated thereon, and then dried and solidified as it is. In this case, it is preferable that the side cross-section be a substantially rectangular shape with the upper side curved downward as shown in FIG. 3 or a substantially trapezoidal shape with the upper side curved downward as shown in FIG. In these side cross-sectional shapes, it is easy to make the height of the highest portion equal to the height of any of the plurality of protrusions even after a coating film is formed thereon. When used as a connection member, it is necessary to make the vertices of the respective protrusions uniformly contact. The size of each projection is shown in FIGS.
It is preferable that the thickness is 1.0 to 5.0 mm, the height He is 0.3 to 1.5 mm, and the pitch Pi of each projection is 1.0 to 8.0 mm. In addition, the shape of a plane cross section (a cross section viewed from the plane direction, hereinafter referred to as a plane cross section) of each convex portion is a circle, an ellipse, a triangle,
Any geometrical figure such as a polygon such as a quadrangle, or a figure combining two or more of these geometrical figures may be used. However, a circle or a quadrangle is preferable from the viewpoint of ease of processing. These projections are
It can be formed by using a normal press.

[0010] A paint is applied to the metal plate on which the convex portions have been formed as described above to form a coating film. As the paint, any of an organic solvent-based paint and an aqueous organic resin paint can be used.
The organic resin constituting the paint is preferably at least one of an acrylic resin, a polyester resin, a urethane resin and a phenol resin. These resins are diluted with a solvent and adjusted to a viscosity of 0.8 to 2.5 Pa · s, preferably 1.0 to 1.8 Pa · s. When the viscosity is less than 0.8 Pa · s, a coating film having a sufficient thickness cannot be obtained, and the corrosion resistance is not sufficient. If it exceeds 2.5 Pa · s, it becomes difficult to apply a uniform thickness. Further, carboxymethyl cellulose or the like may be added to impart flexibility to the coating film. The addition amount is preferably in the range of 0.1 to 40 g / l for the resin liquid having the above viscosity. 0.1g
When the amount is less than 40 g / l, the dispersibility is extremely reduced. Further, when used as an electrical connection member, carbon black or graphite is added as a conductive material. As the carbon black, channel black, furnace black, acetylene black, and Ketjen black can be used. As the graphite, artificial graphite, flaky graphite, scaly graphite, and earthy graphite can be used. The addition amount is preferably in the range of 10 to 350 g / l with respect to the resin liquid having the above viscosity. 10g / l
If it is less than 3, sufficient conductivity cannot be obtained, and if it exceeds 350 g / l, the dispersibility is extremely reduced.

As described above, the coating may be an organic solvent-based coating or an aqueous organic resin coating. When an aqueous resin is used as the organic resin constituting the paint, any of a water-soluble type, a water-dispersed type, and an emulsion type may be used. For example, the aqueous acrylic resin includes polymers and copolymers of acrylic acid and its esters, acrylamide, acrylonitrile, methacrylic acid, and its esters. The functional group of the ester includes a carboxyl group, an amino group, a methyl group, an ethyl group, a butyl group, an amyl group, an ethylhexyl group, and an octyl group. Also, an aqueous ethylene acrylic resin containing an ethylene group is included. As the crosslinking agent, a compound containing a hydrazide group, an epoxy group, or an amino group, a siloxane, an epoxy resin, or the like can be used.

Aqueous polyester resins are those dispersed in water with sodium polyoxyethylene nonyl phenyl ether, sodium polyoxyethylene nonyl phenyl ether sulfate, sodium lauryl sulfate, rosin soap, carboxyl group, sulfone group, sulfate group, Those containing a hydrophilic group such as a phosphate group, an amino group, an ammonium salt, a hydroxyl group, an ether group or an amide group are preferable, and include an alkyd group, a maleic resin and an unsaturated polyester. As a cross-linking agent, a compound obtained by modifying a butylated melamine resin with dimethylol propionic acid, an aqueous blocked isocyanate compound blocked with methylol phenol or methyl ethyl ketoxime,
Compounds containing an epoxy group and an amine group, compounds containing an aziridine and a carboxylic acid group, compounds containing a polyvalent metal with a chelating agent such as zinc acetate or aluminum acetate, hydrazine and diacetone acrylamide can be used.

Aqueous urethane resins include those having a water-soluble carboxyl group or amine group in the terminal group. Examples of the crosslinking agent include a metal crosslinking agent such as a methylated melamine resin, an epoxy resin, and a zinc complex, an aziridine compound, an isocyanate compound, a primary or secondary diamine, or a polyamine, a primary or secondary diamine or a polyamine. And an amino resin containing the same. Resol type obtained by reacting aqueous phenolic resin phenol with formaldehyde under an alkaline catalyst is included. An epoxy resin or the like can be used as a crosslinking agent.

As a method of applying the above paint, a spray coating method, a curtain flow method, an electrostatic coating method, an immersion method and the like can be used. It is preferable to apply by a spray coating method or an electrostatic coating method. After the coating thickness is dried and solidified,
It is preferable that the height is 30 to 150 μm at the top of the projection.
If it is less than 30 μm, the corrosion resistance becomes insufficient, and
If it exceeds μm, it is economically disadvantageous. When the coating film 5 is dried and solidified in the coated state, as shown in FIG. 3 or FIG. 4, the metal plate 1 has a convex portion 2 having a substantially rectangular or substantially trapezoidal side cross section whose upper side is curved downward. In this case, the coating film 5 coated thereon is dried and solidified in a flat state as shown in FIG. 5 or FIG. On the other hand, as shown in FIG. 1 or FIG. 2, when the metal plate 1 has a rectangular or trapezoidal side cross-sectional convex portion having a flat upper side, the coating film 5
Flows from the end to the concave portion 8 between the convex portions, and as shown in FIG. 7 or 8, is dried and solidified in a state of rising upward from the end portion of the convex top portion toward the central portion. For this reason, when the metal plate having the convex portions shown in FIG. 1 or FIG.
As shown in FIG. 9, in a state where the coating film 5 is in a semi-cured state (when the coating surface is pressed with a finger, the coating is deformed but the deformation is not recovered to its original state) before completely solidified. A flat plate 6 is brought into contact with the entire surface of the coating film, and is pressed from above, or the coated metal plate is passed between a pair of rolls to press the coating film surface to form a flat surface. In this way, the object of the present invention is to obtain a coated metal plate in which the tops of the convex portions coated with the coating film are flat.

[0015]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. (Example) Diffusion using a Fe-Cr-based or Fe-Ni-Cr-based stainless steel plate having a thickness of 0.2 mm according to the JIS standard shown in Table 2 to form convex portions by the following three processes. A stainless steel plate having a layer was prepared. A) Protrusion formation → two-layer plating → thermal diffusion treatment B) Two-layer plating → thermal diffusion treatment → convex formation C)) Two-layer plating → convex formation → thermal diffusion treatment . [Two-layer plating] The stainless steel plate on which the projections are formed or not formed is degreased, pickled, washed with water, and nickel sulfate 250
Using a plating bath containing g / l and sulfuric acid at 50 g / l, Ni was electroplated on both surfaces thereof at a bath temperature of 50 ° C. so that the plating amount was 1 g / m ² . Next, after washing with water, Ni was electroplated with a plating amount shown in Table 2 using a Watt bath.
After further washing with water, Sn was electroplated in a plating amount shown in Table 2 using a ferrostan bath. [Thermal Diffusion Treatment] The stainless steel sheet subjected to the two-layer plating is subjected to a heat diffusion treatment under a condition shown in Table 2 in a non-oxidizing atmosphere composed of 95% of nitrogen gas and 5% of hydrogen gas to form a diffusion layer. Formed. [Protrusion Formation] Protrusion formation was performed as follows. That is, using a press device, the dimensions of each part shown in Table 2, that is, the depth of the concave portion at the top of the convex portion: Dp, the height of the convex portion: He, the length of the convex portion (when the front cross section is a circle, A diameter, a length of one side in the case of a square): Le, a pitch: Pi, and a plurality of any of the following four types of side cross-sections and front cross-sections A to D were formed.

[Table 1]

[0016]

[Table 2]

The stainless steel sheet having the diffusion layer with the projections thus obtained was coated on the surface with an organic resin having a resin composition shown in Table 3 containing carbon black or graphite. The composition was applied by a spray method under the conditions shown, and then dried and solidified. A part of the sample applied to the stainless steel plate having the diffusion layer having the convex portion in the shape of A or B, when the coating film is in a semi-cured state, as shown in FIG. 6 abuts and 1 from above
A load 7 of 0 kg / cm ² was applied, and pressure was applied to flatten the surface of the coating film 5 and then completely solidified. Thus, a sample for characteristic evaluation was prepared.

[0018]

[Table 3]

The samples prepared as described above were evaluated for the following characteristics. [Corrosion resistance] The sample was immersed in a sulfuric acid aqueous solution with pH = 2.0,
Temperature: Removed after elapse of 500 hours in a constant temperature and humidity atmosphere of 60 ° C., and determine the degree of red rust generation on the sample surface using a known Rating N
o.Evaluated by the method. [Adhesion of coating film] After cross-cutting the surface of the surface-treated stainless steel sheet on which the coating film was formed in a grid pattern using a cutter, a cellophane tape (registered trademark) was attached, and then the coating was forcibly peeled off. The peeling state of the coating film was evaluated according to the following criteria. ◎: No peeling was observed. ：: Very slight peeling is observed on the surface layer. X: Peeling is observed at the interface between the coating film and the surface treatment layer.

[Contact Resistance] A carbon plate having a thickness of 0.5 cm, a width of 1.5 cm, and a length of 1.5 cm is sandwiched between the same samples having a width of 1.5 cm and a length of 2 cm, and a tester ( The contact resistance between the samples was measured using HIOKI3540 manufactured by Hioki Electric Co., Ltd.). The two samples are
A portion of 1.5 cm in width × 1.5 cm in length was in contact with the entire area of the carbon plate (1.5 cm × 1.5 cm). Contact resistance immediately after contact (initial), and at 60 ° C, 95
% RH was placed in a thermo-hygrostat, and after 500 hours (elapsed time), two values were measured. Contact resistance is 50mΩ ・ c
The case of m ² or less was evaluated as ○, and the case of exceeding 50 mΩ · cm ² was evaluated as ×. Table 4 shows the results of these evaluations.

[0021]

[Table 4]

As shown in Table 4, when a coated metal plate in which a conductive coating is formed on a surface-treated stainless steel sheet provided with a convex portion having a side cross-sectional shape according to the present invention, corrosion resistance and adhesion of the coating are obtained. And an extremely small contact resistance, and thus an excellent electrical connection member and a gas separator for a fuel cell.

[0023]

According to the present invention, a plurality of convex portions are formed on a metal plate, a coating material is applied thereon, dried and semi-cured. A method of manufacturing a coated metal plate, or a method of forming a plurality of projections having a concave portion on the top of a metal plate, applying a coating material thereon, and drying and solidifying the metal plate. The method is a method for producing a coated metal plate in which the coating is applied, and after being dried and solidified, the concave portion is provided so that the coating surface becomes flat, and the conductive coating film is formed using the production method of the present invention. The coated coated metal plate has excellent corrosion resistance and low contact resistance, and thus can be suitably applied as a connection terminal of a lead storage battery or a fuel cell, and a gas separator for a fuel cell.
Further, the coated metal sheet of the present invention has excellent contact properties, as evidenced by low contact resistance, so that it can be applied as a cooling plate or a heat sink.

[Brief description of the drawings]

FIG. 1 is an example showing a side cross section of a projection provided on a metal plate.

FIG. 2 is another example showing a side cross section of a projection provided on a metal plate.

FIG. 3 is another example showing a side cross section of a projection provided on a metal plate.

FIG. 4 is another example showing a side cross section of a projection provided on a metal plate.

FIG. 5 is an example showing a side cross section of a coating form of a coating film on a convex portion provided on a metal plate.

FIG. 6 is another example showing a side cross section of a coating form of a coating film on a convex portion provided on a metal plate.

FIG. 7 is another example showing a side cross section of a coating form of a coating film on a convex portion provided on a metal plate.

FIG. 8 is another example showing a side cross section of a coating form of a coating film on a convex portion provided on a metal plate.

FIG. 9 is a schematic explanatory view showing a method of applying a coating film to a metal plate, pressing the coating film surface after semi-curing, and forming the coating film flat.

[Explanation of symbols]

 Reference Signs List 1 metal plate 2 convex portion 3 top portion 4 concave portion 5 coating film 6 flat plate 7 load 8 concave portion between convex portions Dp concave portion depth He convex portion height Le convex portion length Pi convex portion pitch

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B05D 7/24 302 B05D 7/24 302V 302T 302S 303 303B B32B 15/08 B32B 15/08 G C23C 28/00 C23C 28/00 A H01M 2/30 H01M 2/30 B 8/02 8/02 Y (72) Inventor Kenichi Takagi 1296 Higashi-Toyoi, Kudamatsu-shi, Yamaguchi Prefecture F-term in Toyo Kohan Co., Ltd. Technical Research Institute 4D075 BB05Z BB24Z BB26Z BB27Z CA22 DA07 DB01 DB04 DC19 EB22 EB32 EB35 EB38 EB52 EB56 EC01 4F100 AA37D AB01A AB04A AB16B AB21C AD11D AK01D AK24D AK33D AK41D AK51D BA02 BA04 BA07 BA10A BA10D CA02D CC00D DD01 DD01A DD01B DD01C EH46 EH71 EH71B EH71C EJ08 EJ19 GB41 JB12D JG01 JK14 JL11 4K044 AA01 AA03 BA06 BA10 BA21 BB04 BB11 BB14 CA07 CA18 CA42 CA53 CA67 5H022 AA16 BB00 BB06 BB22 CC16 EE01 EE03 5H026 AA02 BB01 BB02 BB04 CC03 EE02 EE05 EE18

Claims (16)

[Claims] 1. A method in which a plurality of convex portions are formed on a metal plate, a coating material is applied thereon, and the plate is dried and semi-cured. A method for producing a coated metal sheet, characterized by being formed flat. 2. A method for producing a coated metal plate, comprising forming a plurality of convex portions having a concave portion on the top on a metal plate, applying a coating material thereon, and drying and solidifying the coating so that the coating film surface becomes flat. 3. A plurality of projections are formed on a metal plate, and then a lower layer is plated with Ni and an upper layer is plated with Sn, and a coating is applied on a diffusion layer formed by heat diffusion. The method for producing a coated metal sheet according to claim 1 or 2, wherein steps are taken. 4. A metal plate having a lower layer of Ni plating and an upper layer of Sn
Applying a two-layer plating consisting of plating, and then forming a plurality of convex portions on a metal plate having a diffusion layer formed by thermal diffusion treatment,
3. A step of applying a paint thereon.
3. The method for producing a coated metal sheet according to item 1. 5. A metal plate having a lower layer of Ni plating and an upper layer of Sn
The coated metal plate according to claim 1 or 2, wherein a plurality of convex portions are formed after the two-layer plating is performed, and a step of applying a paint thereon after subjecting the two-layer plating layer to heat diffusion treatment. Manufacturing method. 6. The method according to claim 1, wherein a side surface cross section of the plurality of protrusions is rectangular or trapezoidal, and each of the protrusions has the same height. 3. The method for producing a coated metal sheet according to item 1. 7. A coated metal plate having a coating on a metal plate on which a plurality of projections are formed, wherein the tops of the projections coated with the coating are flat. 8. The coating according to claim 7, wherein a side cross section of the convex portion is rectangular or trapezoidal, and each convex portion coated with a coating film has the same height. Metal plate. 9. A coated metal plate in which a coating is coated on a metal plate on which a plurality of convex portions having concave portions on the top are formed,
A coated metal plate, wherein a top surface of a convex portion having a concave portion on a top coated with a coating film is flat. 10. The side cross section of the convex portion having a concave portion at the top is substantially rectangular or trapezoidal with its upper side curved downward, and the highest portion of each convex portion coated with a coating film has the same height. The coated metal plate according to claim 9, comprising: 11. The metal plate is a stainless steel plate in which a lower layer is plated with Ni and an upper layer is plated with Sn, and has a diffusion layer formed by a thermal diffusion process. Item 10. The coated metal sheet according to any one of Items 7 to 10. 12. The coated metal sheet according to claim 11, wherein the stainless steel sheet is a Fe—Cr-based or Fe—Ni—Cr-based stainless steel sheet. 13. The coating film according to claim 7, wherein the coating film contains carbon black or graphite, an organic resin, and a crosslinking agent for the organic resin. Painted metal plate. 14. The method according to claim 13, wherein the organic resin is at least one of an acrylic resin, a polyester resin, a urethane resin and a phenol resin.
A painted metal plate as described in. 15. An electrical connection member using the coated metal plate according to claim 7. Description: 16. A gas separator for a fuel cell using the coated metal plate according to claim 7. Description: