WO2006090775A1

WO2006090775A1 - Coating film, article covered with coating film, and method for corrosion-resistant coating

Info

Publication number: WO2006090775A1
Application number: PCT/JP2006/303261
Authority: WO
Inventors: Kazuhisa Fujii; Takabumi Nagai; Hideaki Asai
Original assignee: Daikin Industries, Ltd.
Priority date: 2005-02-23
Filing date: 2006-02-23
Publication date: 2006-08-31

Abstract

In a mixing/dispersing part, CO2, a surfactant, and a nickel plating liquid are mixed and dispersed to produce a plating dispersion. The plating dispersion is fed into a plating tank provided with a pair of electrodes. In the plating tank, CO2 is brought to a supercritical state, and voltage is applied to the electrodes for electroplating. After the formation of a nickel film on a substrate, a gold plating liquid is fed into the plating tank for electroless plating. As a result, the nickel film is replaced by gold in the gold plating liquid to form a gold film.

Description

Coating film, article coated with coating film and corrosion-resistant coating method

Technical field

TECHNICAL FIELD [0001] The present invention relates to a coating film for ensuring corrosion resistance, an article coated with the coating film, and a corrosion-resistant coating method.

Background art

[0002] In order to prevent corrosion and discoloration, the surface of an article is often coated with another substance. Generally, a synthetic resin is used as a corrosion-resistant coating material. However, synthetic resins are not as heat conductive as conductive materials. Therefore, when the article is required to have conductivity or thermal conductivity, the article surface is often covered with a noble metal.

As a method for forming a coating film, for example, there is a plating process. Patent Document 1 discloses a plating technique using a supercritical substance and an electrolyte solution (plating solution). In this case, the plating bath contains a substance in a supercritical state, which promotes the diffusion of ions contained in the plating solution and provides a high-quality coating film. Patent Document 1: Japanese Patent No. 3571627

Disclosure of the invention

[0004] By the way, when plating is performed, problems such as pinholes and cracks formed in the coating film, and a rough surface may occur. When a pinhole is formed on a noble metal, the material in the plating solution chemically reacts with the base metal of the metal through the pinhole, and corrosion is likely to occur.

[0005] Therefore, the corrosion resistance of the coating film has been improved by forming a thick film by plating and eliminating pinholes. However, such a method of increasing the thickness of the film increases the amount of noble metal used and increases the cost required for forming the coating film.

[0006] An object of the present invention is to provide a coating film excellent in corrosion resistance without increasing the manufacturing cost !, an article coated with the coating film, and a corrosion-resistant coating method. [0007] In order to solve the above problems, according to a first aspect of the present invention, a coating film for covering an object and ensuring corrosion resistance includes a noble metal film, , Formed by plating using a plating solution and a diffusion fluid that enhances the diffusing power of the plating solution c

[0008] With the above configuration, a noble metal film having no pinhole can be formed thinner than the conventional one. Therefore, since the amount of noble metal used is small, a coating film having excellent corrosion resistance can be manufactured at low cost.

[0009] According to a second aspect of the present invention, there is provided a coating film for covering an object and ensuring corrosion resistance, provided on the surface of the object, and a plating solution and a diffusion of the plating solution A base film formed by a first staking process using a diffusion fluid that enhances force, and a noble metal film provided on the base film and formed by a second staking process. In that case, it is possible to form a good base film having a flat surface and no pinholes. By forming the noble metal film on the base film having no pinhole, the corrosion resistance of the object can be ensured even if the noble metal film is formed thin. Accordingly, since the amount of noble metal used is small, a coating film having excellent corrosion resistance can be manufactured at low cost.

[0010] In the above coating film, it is desirable that the second tacking process is a substitution tacking process. In that case, since the surface portion of the base film is replaced to form the noble metal, the surface of the noble metal film can be formed flat if the surface of the base film is flat. As a result, a coating film excellent in corrosion resistance can be formed with fewer noble metals. In addition, when a cyan bath is used to form a noble metal film, it is not necessary to make the plating solution high in pressure, so that generation of cyan gas can be suppressed.

[0011] In the above coating film, it is desirable that the thickness of the base film is lOnm or more. Normally, the grain size (particle size) of a metal is about several nanometers. By ensuring the thickness of the underlayer to be at least 10 ηm, a good underlayer without pinholes can be formed. A coating film having excellent corrosion resistance can be formed thinly.

[0012] In the coating film, the diffusion fluid is preferably a supercritical fluid or a subcritical fluid. In that case, since the diffusion of the plating solution is effectively promoted, a coating film having more excellent corrosion resistance can be formed. [0013] In the above coating film, the diffusion fluid is preferably carbon dioxide. In that case, CO dissolves the hydrogen produced by the side reaction of plating.

2

Generation can be further suppressed.

[0014] In the coating film, in the plating treatment using a diffusion fluid, it is desirable to add a dispersion accelerator that also serves as a fluorine-based compound and promotes dispersion of the plating solution. In that case, compared with the case where a dispersion accelerator is not used or the case where a hydrocarbon surfactant is used, the surface of the plating film becomes smoother and a coating film having excellent corrosion resistance can be formed.

[0015] A third aspect of the present invention is an article whose surface is coated with a coating film in order to ensure corrosion resistance, the coating film comprising a plating solution for forming a noble metal film, and diffusion of a plating solution It is formed by a plating process using a diffusion fluid that enhances the force. In that case, a noble metal film without pinholes can be formed thinner than before. Therefore, since the amount of precious metal used is small, a coating film with excellent corrosion resistance can be manufactured at low cost.

[0016] A fourth aspect of the present invention is an article whose surface is coated with a coating film to ensure corrosion resistance, wherein the coating film enhances the diffusing power of the plating solution and the plating solution. And a noble metal film formed on the undercoat film and formed on the undercoat film by the second sticking process. In that case, it is possible to form a good base film having a flat surface and no pinholes. Further, by forming the noble metal film on the base film without the pinhole, the corrosion resistance of the object can be ensured even if the noble metal film is formed thin. Therefore, since the amount of noble metal used is small, a coating film excellent in corrosion resistance can be manufactured at low cost.

[0017] In the article coated with the coating film, in the first staking treatment, a dispersion accelerator made of a fluorine compound and accelerating dispersion of the staking solution is added, so that the base film becomes It is desirable to be formed. In that case, compared with the case where a dispersion accelerator is not used or the case where a hydrocarbon surfactant is used, the surface of the plating film becomes smoother and a coating film having excellent corrosion resistance can be formed.

[0018] A fifth aspect of the present invention includes a noble metal film or an undercoat film, and the thickness of the clasp film is 10η. It is desirable to coat with a coating film that is at least m. Normally, the grain size (particle size) of a metal is about several nanometers. By ensuring the thickness of the underlying layer is at least lOnm, a good underlying film without pinholes can be formed, which in turn improves corrosion resistance. An excellent coating film can be formed thin.

[0019] A sixth aspect of the present invention is a method of forming a coating film for covering an object and ensuring corrosion resistance, using a plating solution and a diffusion fluid that enhances the diffusing power of the plating solution. A first step of forming a base metal film on the object by an irritating process; and a second step of forming a noble metal film on the base metal film using a replacement plating process. . In that case, it is possible to form a good base film having a flat surface and no pinholes. By forming the noble metal film on the base film without pinholes, the corrosion resistance of the object can be ensured even if the noble metal film is formed thin. Therefore, since the amount of noble metal used is small, a coating film with excellent corrosion resistance can be produced at low cost.

[0020] In the method of forming the coating film, in the first step, the base film may be formed by adding a dispersion accelerator that is made of a fluorine-based compound and that promotes dispersion of the tacking liquid. desirable. In that case, compared with the case where a dispersion accelerator is not used or the case where a hydrocarbon surfactant is used, the surface of the plating film becomes smoother and a coating film having excellent corrosion resistance can be formed.

Brief Description of Drawings

FIG. 1 is a schematic diagram showing the overall configuration of a plating apparatus according to the present embodiment.

FIG. 2 is a flowchart showing a coating film forming process according to the embodiment.

FIG. 3 is an optical micrograph of the coating film of Example 3.

FIG. 4 is an optical micrograph of the coating film of Comparative Example 3.

BEST MODE FOR CARRYING OUT THE INVENTION

[0022] (First embodiment)

Hereinafter, a first embodiment of the present invention will be described. In the embodiment, carbon dioxide in a supercritical state (hereinafter referred to as supercritical CO) is used as the diffusion fluid. CO

2 2 The critical point is 7.4 MPa at 31 ° C. In the present embodiment, a conventional supercritical plating apparatus is used. The plating equipment is equipped with a pressure-resistant plating tank. The plating bath is placed in a thermostatic layer maintained at about 50 ° C. A plating solution and a dispersion accelerator are enclosed in the plating tank. The plating tank is provided with a stirring bar, and the stirring bar is rotated by a stirrer installed outside. The rotation speed of the stirrer is set to 600 rpm. A brass plate serving as a cathode is disposed in the plating tank. The plating tank is connected to a supply pipe that supplies supercritical CO. The plating tank is connected to the discharge pipe,

2

Furthermore, a pressure regulator for adjusting the pressure in the plating tank is disposed in the discharge pipe.

[0024] (Example 1)

In supercritical CO, using a brass plate for the cathode and a titanium plate coated with platinum for the anode

2 made a money. As the plating solution, a commercially available acidic gold plating bath (Au Purity Chemical Laboratory, Au-Metsuki Solution K-24EA10) was used. The plating solution, fluorine-based as compound (F (CF (CF) CFO ) CF (CF) COOCH CH OCH) was 0.5 wt ^_0/0 added to CO. This

3 2 3 3 2 2 3 2

This fluorine compound is a fluorine compound having a nonionic hydrophilic group. By using this fluorine compound, high pressure CO

2 and moisture (plating solution) act to promote dispersion, and a high-quality metal film is formed. The volume ratio of supercritical CO to the solution is 7: 3, bath temperature

2

Was plated at a temperature of 50 ° C, a bath pressure of lOMPa, and a current density of 0.5 AZdm ² for 200 seconds. As a result, a gold plating film having a thickness of about 1 μm was formed on the brass plate of the cathode.

[Example 2]

Nickel plating was performed in supercritical C02 using a brass plate for the cathode and a nickel plate for the anode. As the plating solution, nickel sulfate 280 gZL, nickel chloride 60 g / L, boric acid 50 gZL, and a Watt bath with an appropriate amount of brightener power were used. The Watts bath, (F (CF (CF) CF O) CF (CF) COOCH CH OCH) as a fluorine-based compound were added 0.5 wt ^_0/0 to CO. Super

3 2 3 3 2 2 3 2

The volume ratio of critical CO to acidic gold bath is 7: 3, the bath temperature is 50 ° C, and the bath pressure is lOMPa.

2

It was. Then, while the plating bath was stirred, current application was performed at a current density of 5AZdm ² for 80 seconds to perform the plating process. As a result, a nickel plating film with a thickness of about 1 μm was formed on the brass plate. [0026] Subsequently, substitution brassing was performed on the brass plate on which the nickel plating film was formed. A commercially available plating bath (Au High Liquid Chemical Laboratory Au-Mekking Solution K-24N) was used as the replacement plating solution. Then, the bath temperature was set to 70 ° C., and a brass plate was immersed in the plating bath for 10 minutes to perform a gold plating process. Thereafter, the brass plate was washed with water.

[0027] (Comparative Example 1)

Replacement brass plating was performed on the brass plate. A commercially available plating bath (Au Purity Chemical Laboratory, Au-Mekking Solution K-24N) was used as the substitution gold plating solution. Then, the bath temperature was set to 70 ° C., and the brass plate was immersed in the plating bath for 10 minutes for plating treatment. Thereafter, the brass plate was washed with water.

[0028] (Comparative Example 2)

Nickel plating was performed using a brass plate as the cathode and a nickel plate as the anode. The plating solution used was a Watt bath consisting of 280 gZL of nickel sulfate, 60 g, L of nickel chloride, 50 gZL of boric acid, and an appropriate amount of a fluorescent agent. The bath temperature was set to 50 ° C., and the plating was performed by energizing with a current density of 5AZdm ² for 80 seconds. As a result, a nickel plating film with a thickness of about 1 μm was formed on the brass plate.

[0029] Subsequently, substitution brassing was performed on the brass plate on which the nickel plating film was formed. A commercially available plating bath (Au High Liquid Chemical Laboratory Au-Mekking Solution K-24N) was used as the replacement plating solution. Then, the bath temperature was set to 70 ° C., and the brass plate was immersed in the plating bath for 10 minutes to perform the gold plating process. Thereafter, the brass plate was washed with water.

[0030] (Example 3)

Gold plating was performed in supercritical C02 using a brass plate as the cathode and a titanium plate coated with platinum as the anode. As the plating solution, a commercially available acid gold plating bath (Au Pure Solution K-24EA10, Purity Chemical Laboratory Co., Ltd.) was used. The acidic gold plated bath, and a fluorine-based compound (F (CF (CF) CF O) CF (CF) COOCH CH OCH) 0. 5 wt ^_0/0 pressurized against CO

3 2 3 3 2 2 3 2

Yeah. The volume ratio of supercritical CO to acidic gold bath is 7: 3, the bath temperature is 50 ° C, and the bath pressure is

2

lOMPa. Then, while stirring the plating bath, a current was applied at a current density of 0.5 AZdm ² for 60 seconds to perform plating. As a result, a gold plating film having a thickness of about 0.3 m was formed on the brass plate. [0031] (Comparative Example 3)

Using a brass plate for the cathode and a titanium plate coated with platinum for the anode, normal gold plating was performed. As the plating solution, a commercially available plating bath (Au Purity Chemicals Co., Ltd. Au plating solution K-24EA10) was used. The bath temperature was set to 50 ° C., and a current density of 0.5 AZdm ² was applied for 60 seconds to perform plating. As a result, a gold plating film having a thickness of about 0.3 m was formed on the brass plate.

[0032] The brass plate coating obtained in Example 1 was immersed in lmolZL hydrochloric acid, lmolZL nitric acid, and ImolZL sulfuric acid for 24 hours. Similarly, the brass plate coatings obtained in Example 2 and Comparative Examples 1 and 2 were immersed in lmolZL hydrochloric acid, lmolZL nitric acid, and ImolZU sulfuric acid for 24 hours. As a result, the brass plate coating of Example 2 showed no change in any of hydrochloric acid, nitric acid and sulfuric acid. In contrast, corrosion was confirmed in the brass plate coatings of Comparative Examples 1 and 2 in all cases of hydrochloric acid, nitric acid, and sulfuric acid.

[0033] Next, the brass plate coating bodies obtained in Example 3 and Comparative Example 3 were immersed in 1 mol ZL of sulfuric acid aqueous solution at room temperature for 24 hours. Thereafter, the coating films of Example 3 and Comparative Example 3 were observed using an optical microscope. As shown in the optical micrograph of FIG. 3, the coating film of Example 3 was strong without any corrosion. From this result, it can be seen that according to the present invention, excellent corrosion resistance is exhibited even when the thickness of the gold plating film is less than 1 μm. On the other hand, the coating film of Comparative Example 3 was confirmed to be corroded, as shown in FIG.

[0034] (Second embodiment)

Next, a second embodiment embodying the present invention will be described with reference to FIGS. In this embodiment, a nickel (Ni) film is formed as a base film, and a gold (Au) film is formed thereon. Similar to the first embodiment, the nickel film is electrolyzed using supercritical CO as the diffusion fluid.

2

It is formed by spitting.

[0035] As shown in FIG. 1, the plating apparatus comprises a cleaning liquid tank 11, a high-purity CO tank 21, and a dispersion promoting

2

It has an accelerator tank 31, a Ni plating solution tank 41, and an Au plating solution tank 51. Further, the plating apparatus has a mixing tank 30, a mixing / dispersing section 60, and a tub 61. [0036] The cleaning liquid tank 11 stores the cleaning liquid. Pure water is used as the cleaning liquid. The cleaning liquid tank 11 is connected to the mixing and dispersing unit 60 via a cleaning liquid supply pipe. The cleaning liquid supply pipe includes a liquid pump 12, a heating unit 13, and a supply valve 14. The liquid pump 12 pressurizes the cleaning liquid. The heating unit 13 heats the cleaning liquid. The supply valve 14 communicates and shuts off the cleaning liquid tank 11 and the mixing and dispersing unit 60. That is, the supply of the cleaning liquid to the mixing / dispersing unit 60 or the supply of the cleaning liquid is stopped by opening / closing control of the supply valve 14.

[0037] The high-purity CO tank 21 contains CO as a diffusion fluid. High purity CO tank 21

2 2 2 is connected to the mixing tank 30. The high purity CO tank 21 is connected via a CO supply pipe.

2 2 and connected to the mixing and dispersing unit 60. The CO supply pipe consists of a liquid pump 22, a heating unit 23 and

2

Includes supply valve 24. The liquid pump 22 pressurizes CO. The heating unit 23 heats CO.

twenty two

The supply valve 24 communicates and shuts off the high-purity CO tank 21 and the mixing and dispersing unit 60. Supply

2

By controlling the opening / closing of the valve 24, CO is supplied to the mixing / dispersing section 60, or

2 2 Supply is stopped.

[0038] Further, the dispersion accelerator tank 31 contains a dispersion accelerator. A fluorine-based compound is used as a dispersion accelerator.

[0039] The fluorine-based compound includes a fluorine group and a hydrophilic portion. High pressure C as a fluorine compound

From the viewpoint of sufficiently exhibiting the dispersion promoting action even in O, preferably the nonionic parent

2

A fluorine-based compound having an aqueous group is used.

[0040] Further, examples of the fluorine group include those having a hetero atom in a carbon chain such as a perfluoroalkyl group having a straight chain or a branched chain, or a perfluoropolyether group. Among these, perfluoroalkyl groups having about 3 to 15 carbon atoms are used, and those containing a hetero atom in the carbon chain, those having about 3 to 50 carbon atoms are used.

[0041] Examples of the hydrophilic group include polar groups such as ether, ester, alcohol, thioether, thioester, and amide. Of these, fluorine surfactants in which the fluorine group is a perfluoropolyether group and the hydrophilic group is a short-chain polyethylene glycol group are particularly excellent.

[0042] A hydrocarbon-based surfactant that is a conventional dispersion accelerator is a long-chain polyethylene glycol. It has a problem that it contains a single group and is chemically unstable. In contrast, fluorine compounds are chemically stable, and therefore, their dispersion promoting action can be maintained over a long period of time. In addition, the possibility of foreign substances derived from hydrocarbon-based decomposition products is reduced.

[0043] The fluorine-based compound is a hydrophobic fluorine group. Therefore, dispersion of CO and plating liquid

2

The time during which the state can be maintained (dispersion holding time) is short. This means that the plating solution and CO can be separated easily.

2

Because it separates, it is excellent in handling. When this fluorine-based compound is used, the dispersion of the plating solution can be separated into CO and a plating solution in about several seconds to several tens of seconds when the dispersion operation is stopped.

2

Release.

The dispersion accelerator tank 31 is connected to the mixing tank 30. Mixing tank 30 consists of CO supplied from high-purity CO tank 21 and dispersion promotion supplied from dispersion promoter tank 31.

twenty two

It is a tank that contains a liquid mixture with the agent. The mixing tank 30 is connected to the mixing and dispersing unit 60 through a supply pipe. The supply pipe includes a liquid pump 32, a heating unit 33, and a supply valve 34. The liquid pump 32 raises the pressure of the mixed liquid supplied from the dispersion accelerator tank 31 and sends it out to the heating unit 33. The heating unit 33 heats the mixed liquid of CO and the dispersion accelerator. Supply valve 34

2

The mixing tank 30 and the mixing / dispersing section 60 are communicated and disconnected. By controlling the opening and closing of the supply valve 34, the mixed liquid of CO and the dispersion accelerator is supplied to the mixing / dispersing unit 60, or the mixed liquid is mixed.

2

Supply of the mixed solution is stopped.

[0045] The Ni plating solution tank 41 stores a Ni plating solution. The Ni plating solution tank 41 is provided with a heating and heat retaining means for heating the Ni plating solution at a predetermined temperature (eg, about 50 ° C). The Ni plating solution tank 41 is connected to the mixing / dispersing unit 60 via a base plating solution supply pipe. The undercoat liquid supply pipe includes a liquid pump 42 and a supply valve 44. The liquid pump 42 pressurizes the Ni plating solution and sends it to the mixing and dispersing unit 60. The supply valve 44 communicates and shuts off the Ni plating solution tank 41 and the mixing and dispersing unit 60. In other words, the Ni plating solution is supplied to the mixing and dispersing unit 60 or the supply of the Ni plating solution is stopped by opening / closing control of the supply valve 44.

[0046] The mixing and dispersing unit 60 mixes the mixed solution and the Ni plating solution to obtain a dispersed state. A mixer is disposed in the mixing and dispersing unit 60, and a disperser is connected to the downstream side of the mixer. Ni Me The plating solution and the mixture of CO and dispersion accelerator are supplied to the mixer to produce the plating mixture.

2

Made. The disperser includes a stirring bar. When the plating mixture is supplied to the disperser from the mixer, the stirrer rotates and the components in the mixture are uniformly dispersed.

[0047] The Au plating solution tank 51 stores an Au plating solution. The Au plating solution tank 51 is provided with a heating and heat retaining means for heating the Au plating solution to a predetermined temperature (for example, about 50 ° C.) and keeping it warm. The Au plating solution tank 51 is connected to a plating tank 61 through a noble metal plating solution supply pipe. The noble metal plating liquid supply pipe includes a liquid pump 52 and a supply valve 54. The liquid pump 52 pressurizes the Au plating solution and sends it out to the plating tank 61. The supply valve 54 communicates and shuts off the Au plating solution tank 51 and the mating tank 61. That is, by the opening / closing control of the supply valve 54, the power for supplying the Au plating solution to the plating tank 61 or the supply of the Au plating solution is stopped.

[0048] In the plating tank 61, a plating process for forming a coating film is performed. In the plating tank 61, the substrate W is accommodated as an object to be coated. The plating tank 61 includes a pair of electrodes. One of the two electrodes is a negative electrode and is connected to the substrate W. Further, the plating tank 61 includes a block heater (not shown). The block heater heats the inside of the plating tank 61 to adjust the plating dispersion to a predetermined temperature. When the Ni film is attached, the liquid temperature is set to about 50 ° C so that CO is in a supercritical state.

2

The plating tank 61 is connected to the separation tank 65 via a discharge pipe including a shutoff valve 64. The shutoff valve 64 communicates and shuts off the mixing and dispersing unit 60 and the separation tank 65. By controlling the opening / closing of the shut-off valve 64, the force for discharging the used plating solution to the outside or the discharge of the plating solution is stopped.

[0050] The separation tank 65 separates the CO-powered liquid containing the dispersion accelerator. And CO is water

2 2 Element and oxygen are removed, and the power is supplied to the mixing tank 30. On the other hand, the Ni plating solution is discharged to a Ni plating solution regenerating device, an Au plating solution regenerating device or a waste solution tank (not shown) via a discharge switching valve. In the Ni plating solution regenerator, each component in the Ni plating solution is adjusted after impurities are removed. The regenerated Ni plating solution is returned to the Ni plating solution tank 41 again. In the Au plating solution regenerator, each component in the Au plating solution is adjusted after impurities in the Au plating solution are removed. The Au plating solution regenerated in this way is A u Returned to the plating solution tank 51 again. Furthermore, used cleaning liquid and unrecycled Ni plating solution are discharged to the waste liquid tank.

In addition, the plating apparatus includes a process control unit (not shown) as control means. The process control unit is composed of CPU, RAM, ROM, etc., and according to the stored program, each liquid pump 12, 22, 32, 42, 52, each caloric heat unit 13, 23, 33, each supply valve 14, 24, 34, 44

, 54, shut-off valve 64 and electrodes are controlled.

Next, a plating method using the above-described plating apparatus will be described with reference to FIGS. 1 and 2.

First, a Ni film is formed as a base for the Au film. At that time, the process control unit opens the supply valves 3 4 and 44, heats the heating unit 33, and drives the liquid pumps 32 and 42. The process control unit drives the disperser of the mixing / dispersing unit 60. Then, the mixed solution of CO and dispersion accelerator supplied from the mixing tank 30 and the Ni solution supplied from the Ni plating solution tank 41

2

The liquid is supplied to the mixing and dispersing unit 60 in a pressurized and heated state. In the disperser of the mixing and dispersing unit 60, the plating mixed solution is stirred and uniformly dispersed. The plating mixture is supplied to the plating tank 61 in a uniformly dispersed state. In this embodiment, CO, minutes

2 Because the dispersion holding time of the dispersion accelerator and Ni plating solution is short, the process control unit can control each liquid pump 32 so that the dispersion dispersed in the mixer can flow through the plating tank 61 within the dispersion holding time. , 42 is controlled.

[0054] At the same time, in the plating tank 61, the electrodes are energized and electroplating is performed by the plating dispersion. As a result, the Ni film 101 is formed on the surface of the substrate W. Meanwhile, the shutoff valve 64 is open.

[0055] The plating dispersion is discharged from the plating tank 61 to the separation tank 65 before the dispersion holding time elapses. When the plating solution is discharged into the separation tank 65, CO containing a dispersion accelerator and Ni plating

2

Separated into liquid. CO and dispersion promoters are used after gases such as hydrogen and oxygen are removed

2

The mixture is refluxed to the mixing tank 30. On the other hand, the remaining Ni plating solution is discharged to the Ni plating solution regenerator. In the Ni plating solution, after impurities are removed, each component contained in the plating solution is adjusted. After the Ni plating solution is regenerated in this way, it is returned to the Ni plating solution tank 41. [0056] Thereafter, the driving of the liquid pumps 32 and 42 and the heating of the heating unit 33 are continued, and the supply of the plating dispersion to the mating tank 61 and the discharge from the metching tank 61 are continued.

Next, after the Ni film 101 is formed to a predetermined thickness (eg, 1 μm), the Au film 102 is formed by electroless plating (substitution plating). When a predetermined time has elapsed, the process control unit stops energization of the electrode of the plating tank 61, closes the supply valve 44, and stops the driving of the liquid pump 42. As a result, the supply of the Ni plating solution to the mixing and dispersing unit 60 is stopped, and the CO

2 Only the mixed solution is supplied to the messenger tank 61 via the mixing and dispersing unit 60. Supply of CO mixture

2

By continuing for a predetermined time, the Ni plating solution remaining in the plating tank 61 is completely discharged. Subsequently, the process control unit opens the supply valve 14 and drives the liquid pump 12. Thus, the cleaning liquid is supplied from the cleaning liquid tank 11 to the mixing and dispersing unit 60, and the inside of the plating tank 61 is cleaned. After supplying the cleaning liquid for a predetermined time, the process control unit closes the supply valve 14 and stops driving the liquid pump 12. As a result, the supply of the cleaning liquid is stopped, and the CO mixed liquid containing the dispersion accelerator is supplied to the plating tank 61. This mixed solution flows through the plating tank 61.

2

As a result, the cleaning liquid is discharged from the plating tank 61.

[0058] Thereafter, the process control unit drives the liquid pump 52, opens the supply valve 54, and closes the shut-off valve 64. Then, the Au plating solution is supplied from the Au plating solution tank 51 and stored in the plating tank 61. When the plating bath 61 is filled with the Au plating solution, the process control unit stops the solution pump 52 and closes the supply valve 54. At this time, in the plating tank 61, electrons are received from the Ni film 101 having a higher ionization tendency than the Au ion force Au ions in the Au plating solution. As a result, on the surface of the substrate W, Ni is replaced with Au, and the Au film 102 is formed.

[0059] The process control unit closes the supply valve 54 and opens the shut-off valve 64 when the force has also passed for a predetermined time. Then, the Au plating solution in the plating tank 61 is discharged to the separation tank 65, and discharged from the separation tank 65 to the waste liquid tank at once. Thus, the plating process is completed.

[0060] According to the present embodiment, the following effects can be obtained.

[0061] (l) Before forming the Au film 102, a plating component containing CO and Ni plating solution in a supercritical state

2

A Ni film 101 is formed on the substrate W by using a powder. In that case, the supercritical state of CO

2 The diffusion force promotes the diffusion of the Ni plating solution and improves the adhesion of the Ni film 101. You can. Therefore, the Ni film 101 without a pinhole can be formed. Then, by forming the Au film 102 on the Ni film 101 having no pinholes, the corrosion resistance of the substrate W can be ensured even if the Au film 102 is formed thin. Therefore, since the amount of Au used is small, a coating film having excellent corrosion resistance can be manufactured at low cost.

(2) When forming the Ni film 101, supercritical CO is used as a diffusion fluid.

2

In that case, the hydrogen generated during the plating process dissolves in the supercritical state of CO.

2

Hydrogen, which is a cause of generation of holes, can be removed from the surface of the substrate W. Further, the Ni film 101 is formed by continuously supplying the swell dispersion from the mixing / dispersing part 60 to the staking bath 61 and continuously discharging it from the staking bath 61. In this case, CO containing hydrogen

2 Since it is quickly discharged from the tank 61, it is possible to avoid reattachment of bubbles to the surface of the substrate W. Therefore, the formation of pin holes in the Ni film 101 can be further suppressed. Further, since the internal pressure of the plating tank 61 is maintained high, the volume of hydrogen gas can be kept small. Therefore, even if air bubbles adhere to the surface of the substrate W and plating is formed on the attached portion, the pinhole can be eliminated.

[0063] (3) In order to mix and disperse CO in a supercritical state and Ni plating solution,

2

Fluorine compounds are used. As a result, the surface of the Ni film 101 can be made flatter than when a dispersion accelerator is not used or when a conventional hydrocarbon surfactant is used. Then, by forming the Au film 102 on the surface of the flat Ni film 101, the corrosion resistance of the substrate W can be ensured even if the Au film 102 is formed thin. Therefore, the amount of Au used is small.

[0064] (4) The Au film 102 is formed by using substitution fitting. In replacement plating, the Ni film 101 is replaced with Au while the surface shape of the Ni film 101 is maintained. Therefore, if the Ni film 101 of the base film is flat, the Au film 102 formed by replacing the Ni film 101 can be flattened. Therefore, the Au film 102 as a noble metal film can be formed extremely thin, and a coating film excellent in corrosion resistance can be formed with fewer noble metals. In addition, in substitution welding, when substitution on the surface of the Ni film 101 is completed, the reaction may be stopped or the reaction may be delayed. Therefore, the Au film 102 is not formed thicker than necessary, and the noble metal Au is not wasted. [0065] (5) The process control unit includes a plating dispersion containing CO, a dispersion accelerator, and a Ni plating solution.

2

The drive of each liquid pump 32, 42 is controlled so that it passes through the plating tank 61 and is supplied to the separation tank 65 within the dispersion holding time. Thus, the plating dispersion is supplied to the plating tank 61 while maintaining the dispersion state. For this reason, it is possible to make the thickness of the Ni film 101 applied to the substrate W uniform.

(6) The Ni film 101 is formed by continuously supplying a plating dispersion containing a Ni plating solution to the plating tank 61 and continuously discharging it from the plating tank 61. In this case, hydrogen generated during the plating process or foreign matter peeled off from the substrate W can be quickly discharged from the plating tank 61. Therefore, the Ni film 101 that does not include foreign matter or pinholes can be formed, and a good coating film can be formed.

[0067] (7) The shut-off valve 64 is closed, and the Au plating solution is sealed in the plating tank 61, so that force displacement tacking is performed. After the replacement staking process is completed, the used Au plating solution is discharged at once. For this reason, since the Au plating solution is used in an amount enclosed in the plating tank 61, the amount of expensive Au plating solution used can be reduced as much as possible.

[8] (8) The thickness of the Ni film 101 formed using supercritical CO is about 1 μm. Usually Ni

2

Since the grain size (particle size) of such a metal is about several nm, the Ni film 101 without pinholes can be formed by securing the thickness of the Ni film 101 to 10 nm or more. In addition, since the size of bubbles (hydrogen) is around 5 μm, it has been difficult to form a film of 4 μm or less. According to the present invention, the Ni film 101 without pinholes can be formed with a thickness of 1 / zm or less, and as a result, a high-quality Au film 102 can be formed.

[0069] The above embodiments may be changed as follows! /.

[0070] In the first embodiment, in order to disperse the supercritical CO and the solution, the fluorine-based compound

2

Although a fluorine-based compound having a nonionic hydrophilic group is used as the product, any other fluorine-based compound containing a fluorine group may be used instead. Further, as a dispersion accelerator, an organic compound other than a fluorine-based compound may be used, or a dispersion accelerator may be omitted.

[0071] · In the second embodiment, replacement plating was performed after the Au plating solution was sealed in the plating tank 61. Instead, replacement was performed while continuously supplying the Au plating solution to the plating tank 61. Me You may go on. From this, a good quality Au film 102 can be formed. In addition, it is possible to suppress an increase in manufacturing cost by regenerating the Au plating solution. In this case, the substitution plating may be performed while stirring the Au plating solution. As a result, the Au film 102 is formed in a shorter time, and the productivity is improved.

[0072] 'In the second embodiment, the Ni film 101 is formed using supercritical CO, and the substitution is performed thereon.

2

Force for forming the Au film 102 by plating Instead of this, the Au film 102 may be formed by using a wet film forming method such as electrolytic plating or electroless plating, or a dry film forming method. Also in this case, since the surface of the Ni film 101 serving as the base film becomes flatter, the Au film 102 can be formed thin and with a uniform thickness. Therefore, a coating film having excellent corrosion resistance can be produced at a low cost.

[0073] In the second embodiment, the Ni film 101 is formed on the substrate W as a base film when the Au film 102 is formed. Instead, supercritical CO and Au plating solution are used instead. Dispersion accelerator

2

The Au film 102 may be formed directly on the substrate W using the plating dispersion dispersed by the above. In this case, by using supercritical CO, a good quality Au film without pinholes 10

2

2 can be formed thinner than before. Therefore, since the amount of Au used is small, a coating film with excellent corrosion resistance can be manufactured at low cost. In this case, an Au plating solution tank 51 containing an Au plating solution is provided in place of the Ni plating solution tank 41. Therefore, the overall configuration of the eyelash device is simplified.

In each of the above embodiments, a noble metal film such as silver (Ag) or platinum (Pt) may be formed instead of the Au film 102.

[0075] 'In each of the above embodiments, instead of the Ni film 101, another metal film may be formed as a base film.

[0076] In each of the above embodiments, instead of supercritical CO, subcritical CO,

2 2 Other fluids in subcritical or supercritical state may be used as diffusion fluids.

Claims

The scope of the claims

[1] A coating film for covering an object and ensuring corrosion resistance,

A coating film comprising a noble metal film, wherein the noble metal film is formed by performing a plating process using a plating solution and a diffusion fluid that enhances the diffusing power of the plating solution.

[2] A coating film for covering an object and ensuring corrosion resistance,

A base film formed by a first plating process using a plating solution and a diffusion fluid that enhances the diffusing power of the plating solution, provided on the surface of the object, and provided on the base film; A coating film comprising a noble metal film formed by a plating process.

[3] The coating film according to [2], wherein the second staking process is a replacement staking process.

[4] The coating film according to [2] or [3], wherein the base film has a thickness of lOnm or more.

[5] The coating film according to any one of claims 1 to 4, wherein the diffusion fluid is a supercritical fluid or a subcritical fluid.

[6] The coating film according to [5], wherein the diffusion fluid is carbon dioxide.

[7] In the plating treatment using the diffusion fluid, a dispersion accelerator that promotes dispersion of the plating solution is added because of the strength of a fluorine-based compound. The coating film as described in 2.

[8] An article whose surface is coated with a coating film to ensure corrosion resistance,

An article coated with a coating film, wherein the coating film is formed by a plating process using a plating liquid that forms a noble metal film and a diffusion fluid that enhances the diffusing power of the plating liquid.

[9] An article whose surface is coated with a coating film in order to ensure corrosion resistance,

The coating film strength The base film formed by the first sticking process using the plating solution and the diffusion fluid that enhances the diffusing power of the plating solution, and the base film provided on the base film and the second sticking process An article coated with a coating film, comprising a noble metal film to be formed.

[10] The base film is formed by adding a dispersion accelerator made of a fluorine compound and promoting dispersion of the plating solution in the first plating process. An article coated with the coating film according to 9.

[11] An article that is coated with a coating film that includes a noble metal film or an undercoat film, and the thickness of the adhesive film is lOnm or more.

[12] A method of forming a coating film for covering an object and ensuring corrosion resistance, wherein the object is formed by plating using a plating solution and a diffusion fluid that enhances the diffusing power of the plating solution. In contrast, a first step of forming a base metal film,

And a second step of forming a noble metal film with respect to the base metal film using a substitution staking process.

[13] The base film according to [12], wherein in the first step, the undercoat film is formed by adding a dispersion accelerator that is made of a fluorine-based compound and promotes dispersion of the plating solution. Corrosion resistant coating method.