JPS6048599B2 - Composite plating film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer composite plating film that is suitably used as a lubricating film, a base film for fluororesin coating, and the like.

Conventionally, it is known that particles such as polytetrafluoroethylene are used as a lubricating film in a metal plating film, but conventional composite plating films of this type are
The adhesion of the particles to the metal plating film was not always sufficient, and there were cases in which considerable pinholes were formed, especially when heat treatment was performed after plating.

Therefore, in order to eliminate the formation of such pinholes, a composite plating film has been formed to be relatively thick, and a method of composite plating to a thickness of 15 μm has usually been adopted. However, forming such a thick composite plating film is not a good idea from the viewpoint of plating work or economically, and depending on the application, forming such a thick composite plating film is not possible. There were times when I couldn't do it. Therefore,
There has been a desire for a composite plating film that has better adhesion than before and is less likely to produce pinholes even at a thin film thickness even when heat treated.

In view of the above circumstances, the present inventors have conducted various studies on composite plating films that are difficult to form pinholes even with a relatively thin film thickness and are suitable for use as lubricating films. It has been found that a metal plating film made of an alkyl vinyl ether copolymer has superior properties compared to other fluorine-based resin composite plating films such as polytetrafluoroethylene.

That is, the metal plating film made of tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer particles has very good adhesion to the metal plating film, and the composite plating film is Even with a fairly thin film thickness of about 3 μm, if this is heat-treated to melt the tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer in the composite plating film, no pinholes will occur, and this will lead to metal plating. It was discovered that the material adhered reliably to the film and was integrated into the composite. Therefore,
In this way, the tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer is integrated into the metal plating film with good adhesion, so this composite plating film can be used as a lubricating film, a wear-resistant film, a corrosion-resistant film, etc. for a long period of time. It has been discovered that it has been used effectively over the years, and that it can also be used extremely effectively as a base film for fluororesin coatings, leading to the present invention.
Noru. The present invention will be explained in more detail below.

The composite plating film according to the present invention contains nickel, cobalt,
Tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (hereinafter referred to as ``PFA'') is co-deposited in a dispersed state on a metal plating film made of copper, lead, tin, silver, or an alloy thereof. Under normal conditions, PFA is almost uniformly dispersed in the metal plating film.

In the PFA composite plating film of the present invention, the PFA is preferably in the form of particles, particularly with an average particle size of 0.05 to 0.5μ.
It is used in the form of particles or short fibers. In addition, as PFA, one in which the alkyl group is a lower alkyl group such as a methyl group or an ethyl group is preferably used. The amount of PFA eutectoided in the PFA composite plating film is:
It is selected as appropriate depending on the intended use, but when used as a lubricating film, wear-resistant film, corrosion-resistant film, or base film for fluororesin coating, the eutectoid content is preferably 15 to 4% by weight. . The PFA composite plating film of the present invention can be obtained by plating using an electroplating solution in which PFA is suspended or an electroless plating solution.

In this case, the electroplating solution may be a Watt bath, a bath containing high chloride concentration, or
vinegar. Electrolytic nickel plating solutions such as nickel fluorinate baths and nickel borofluoride baths; electrolytic cobalt plating solutions such as cobalt sulfate baths and cobalt chloride baths; electrolytic copper plating solutions such as copper sulfate baths and copper borofluoride baths; lead sulfate. , tin baths, lead borofluoride, electrolytic lead such as tin baths, tin tin and dipping liquid, etc.
In particular, it is preferable to use a sulfamic acid bath containing 0.5 mol or more, more preferably 0.8 mol or more of sulfamic acid ions, because it can increase the amount of eutectoid and is less affected by stirring. It is. Examples of electroless plating solutions include electroless nickel plating solutions, electroless cobalt plating solutions, and electroless copper plating solutions that use boron compounds such as hypophosphite or dimethyl porazan as reducing agents. Suitably used. In the plating solution, one or more types of water-soluble cationic, nonionic, and amphoteric surfactants that exhibit cationic properties in the plating solution may be added to cationically charge the PFA. preferable.

In this case, examples of cationic surfactants include quaternary ammonium salts, secondary and tertiary amines, and imidazolines, and examples of nonionic surfactants include polyoxyethylene, polyethyleneimine, and ester. Examples of the amphoteric surfactant include carboxylic acid surfactants, sulfone surfactants, etc., but it is particularly preferable to use a fluorine surfactant having a C-F bond in the molecule. In particular, when a sulfamic acid bath is used as the plating solution, the amount of eutectoid can be increased by simply using a fluorine-based cationic or amphoteric surfactant that exhibits cationic properties in the plating solution. It is preferable to combine a sulfamic acid bath with a fluorine-containing cation or an amphoteric surfactant because a complex plating film can be formed. The amount of the surfactant added to the plating solution is 0.
．． It is preferable to set it as 1-10y/l.

A brightening agent depending on the type of plating liquid, for example, a commercially available brightening agent in the case of electrolytic nickel plating, may be added to the plating liquid, and other additives may also be added as appropriate. can. Further, other water-soluble inorganic or organic particles, short fibers, etc. can also be added. The PFA composite plating film of the present invention is obtained by dispersing PFA in the above-mentioned plating solution and plating using this PFA-dispersed plating solution.
1 to 500 y/l), especially 10 to 200 y/l) in the plating solution.
It is preferable to disperse f1/l.

As the plating conditions for plating, known conditions depending on the type of plating solution can be adopted. P according to the present invention
There are no particular restrictions on the material on which the FA composite plating film is formed, and any material that can be plated, such as metal materials such as steel, cast iron, copper, copper alloy, and aluminum, conductive or activated plastics, ceramics, etc. PF on materials etc.
A composite plating film can be formed.

In this case, the thickness of the PFA composite plating film is appropriately selected depending on the use of the film, the application location, etc., but in the PFA composite plating film of the present invention, PFA is contained in the metal plating film. ．． ] Since the composite is integrated with good adhesion and pinholes are unlikely to occur even when heat treated, it can be formed into a thin film of about 2 to 3 μm), and even with such a thin film thickness, it can sufficiently exhibit its effect. It's something you get. The PFA composite plating film obtained by the method described above can be used as a lubricating film,
There are materials that can be used as wear-resistant films, but if necessary, after composite plating, the PFA composite plating film can be heated to a temperature higher than the melting point of PFA to undergo heat treatment to melt the PFA. In this case, the PFA composite plating film of the present invention, as mentioned above, can generate pinholes even if the film is thin, and when the PFA exposed on the surface of the composite plating film melts, it will flow on the film surface. Polytetrafluoro. The condition after heat treatment is much better than that of a hardened film formed by eutectoiding other fluororesins such as ethylene, and the corrosion resistance is improved. The PFA composite plating film can also be used as a base film for fluororesin coating, but in this case, a fluororesin, such as PFA, polytetrafluoroethylene, polychloroethylene, etc., is applied to the PFA composite plating film after plating. Trifluoroethylene, polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-ethylene copolymer, chlorotrifluoroethylene-alkylene copolymer, vinylitene fluoride-hexafluoropropylene copolymer , vinylidene fluoride-chlorotrifluoroethylene copolymer, vinylidene fluoride-pentafluoro
, propylene copolymer, and other fluororesins by spray coating, powder fluid dip coating, powder electrostatic coating, and roller coating, or by laminating sheets or films of the above fluororesins. The fluororesin film can be integrally laminated on the PFA composite plating film by coating or removing the film, followed by heat treatment.

Even when such a treatment is applied to a PFA composite plating film, a very good fluororesin coating film is formed because there is no formation of pinholes or deterioration of adhesion due to heat treatment. As mentioned above, PFA composite coatings are used as lubricating coatings, wear-resistant coatings, etc., but they are especially used for sliding parts such as vehicles and precision machinery for the purpose of wear resistance and low friction, and non-adhesive coatings. - Suitable for use in metal and non-metal molds and kitchen equipment for the purpose of mold release, and for various architectural and daily use parts for the purpose of corrosion resistance and prevention of discoloration.

EXAMPLES Hereinafter, the present invention will be specifically explained by showing Examples and Comparative Examples. [Example 1] Electroplating was performed on a steel plate under the following conditions using an electroplating solution having the following composition.

Composition Nickel sulfate Nickel chloride Borate Cationic activator Nonionic activator PFA particles PH Conditions 260y/1 45y/' 40Da/1 1Da/l? 0.5g/1 30q/1 4.2 Plating temperature 50°C Cathode current density 4A/d Anode Electric nickel plate stirring Mechanical stirring Note 1: Perfluoroalkyltrimethylammonium salt was used as the cationic activator. .

Note 2: A perfluoroalkyl ethyl oxide adduct was used as the nonionic activator.

In the above electroplating, the plating time is 20 minutes,
Approximately 15 μm eutectoid plating was performed.

PFA in the obtained PFA composite electrolytic nickel plating film
The eutectoid amount was 11% by volume. Next, the steel plate on which the PFA composite plating film was formed was heated to 350°C.
After heat treatment for a minute to melt the PFA, the surface was observed under a microscope, but there were no pinholes, and the PFA particles were dispersed and firmly embedded in the electrolytic nickel plating film.

For comparison, 30q of polytetrafluoroethylene (PTFE) was used instead of PFA in the above-mentioned staining liquid composition.
Plating was carried out under the same conditions using a plating solution of 15 μm (7) PTFE eutectoid electrolytic nickel plating film (PTFE eutectoid amount: 9% by volume).

This was heat treated at 350°C for 1 minute to form a PTFE
After melting, we observed its surface under a microscope and found that
Many pinholes were observed. In addition, on the PFA composite plating film and the PTFE composite plating film, P
After laminating TFE films and heat-treating them to melt and integrate them, a peel test was conducted, and it was found that the adhesion of PFA to the electrolytic nickel plating film was extremely superior to that of PTFE. . [Example 2] Electroplating was performed on a steel plate under the following conditions using an electroplating solution having the following composition.

Composition Nickel sulfamate nickel chloride borate cationic activator PFA particles PH Conditions Plating temperature 50°C 4509/1 40y/1 35y/1 1 da/1 30y/1 4.2 Cathode current density 4A/d Goanode Sulfur-containing Nickel anode stirring Mechanical stirring Plating time 1 minute plating film 3 Film thickness 15 μM PFA eutectoid amount 2 mass % Appearance Uniform grayish white Note 1: Perfluoroalkyltrimethylammonium salt was used as the cationic activator. .

[Example 3] Electroplating was performed on a brass board under the following conditions using an electroplating solution having the following composition.

Composition 4 (Copper sulfate 220y/l Sulfuric acid 60y/.e Refco (brightener manufactured by Uemura Kogyo Co., Ltd.) 2mι/l cationic activator PFA particle conditions Plating temperature Cathode current density Anode stirring Plating time Plating film thickness PFA Analysis amount: 1.2 da/1 50 y/1 25°C 2.5 A/d - Mechanical stirring of phosphorus-containing copper plate Min. A fluoroalkyltrimethylammonium salt was used.

[Example 4] Using an electroless nickel plating solution having the following composition, electroless plating was performed on a steel plate under the following conditions.

Composition Nickel sulfate Hypophosphite Saug Succinic acid Saug Malic acid Stabilizer (p-do-f) Cationic activator PFA particles PH Conditions Plating temperature Plating time Plating film thickness PFA eutectoid amount Appearance 18y/1 24y/1 16y/ ．． E 18y/1 0.003y/1 1g/1 30da/l' 5.6 906C 1 powder 5μm % by volume Uniform grayish white Note 1: Perfluoroalkyltrimethylammonium salt was used as the cationic activator.

After heat-treating the PFA composite plating films obtained in Examples 2 to 4 to melt the PFA, microscopic observation was performed.
All had no pinholes.

Claims (1)

[Claims] 1. A composite plating film characterized by eutectoiding a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer into a metal plating film.