JPH07207496A - Method for producing composite plated metal material having excellent slidability and wear resistance - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a method for producing a composite plated metal material having high self-lubricating property and excellent in slidability and wear resistance. [Structure] Surface-hydrophilized PTFE fine particles and, if necessary, ceramic fine particles are dispersed in a Ni and / or Co-containing plating bath, and the metal material substrate surface is electroplated by this plating bath to form a metal material substrate surface. , PTF
A composite metal plating film containing E fine particles and, if necessary, ceramic fine particles dispersed therein is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a composite plated metal material having excellent wear resistance and slidability. More specifically, according to the present invention, when a plating film of a metal containing nickel and / or cobalt is formed on the surface of a substrate made of various metal materials by an electroplating method, the surface of the metal plating film is hydrophilic. Polytetrafluoroethylene fine particles (hereinafter referred to as hydrophilic P
The present invention relates to a method for producing a composite plated metal material, in which TFE fine particles) are dispersed and co-deposited to thereby significantly improve wear resistance and slidability.

[0002]

2. Description of the Related Art Conventionally, a metal plating film which is required to have high wear resistance and slidability, for example, a ceramic dispersion eutectoid nickel-phosphorus alloy plating film has good results in an environment supplied with lubricating oil. Has been shown. However, the supply of lubricating oil requires a special machine or device such as a pump, which requires a considerably large facility. In addition, since the PTFE composite plating film currently used for the sliding portion is formed by the electroless plating method, the plating forming speed is as slow as about 8 to 10 μm / hr, and the wear resistant film is also formed. It was necessary to further apply molybdenum disulfide or PTFE as a lubricant on the above. Moreover, the conventional composite plating film is in a non-lubricated environment, that is, an environment in which the lubricating oil cannot be used, or the lubricating oil is used but the shape of the sliding portion used is complicated, When it is not sufficiently supplied, its wear resistance and slidability are not satisfactory.

Examples of plating agents using PTFE for forming a eutectoid composite film include Nimflon (Japanese Patent Publication No. 2-54775) manufactured by Uemura Kogyo Co., Ltd. and Enthrone-OMI in the United States.
The company's enloop etc. can be mentioned. Nimflon is PT
FE-containing Ni electroless composite plating agent. The electroless Ni plating method is a plating method in which metallic Ni is deposited by using a reducing agent, but generally has a drawback that the cost is high because the bath life is short and the deposition amount of the plating film is small. . Further, in general, a plating bath for electroless plating contains a large amount of a chelating resin and / or a chelating agent as its components, and thus has a drawback that the treatment of the waste liquid is extremely difficult. Therefore, at present, a plating film or a composite plating film that satisfies productivity, abrasion resistance and slidability at the same time has not been provided.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems of the conventional method and to provide a method for producing a composite plated metal material excellent in wear resistance and slidability. More specifically, the object of the present invention is to eliminate the short bath life and low plating formation rate, which are known as the drawbacks of the PTFE eutectoid electroless nickel plating method, and the plating film itself has excellent wear resistance and It is an object of the present invention to provide a method for producing a composite plated metal material having a slidability and therefore a high self-lubricating property.

[0005]

Means for Solving the Problems As a result of intensive studies for solving the above-mentioned problems, the present inventors have found that PTFE fine particles whose surface has been made hydrophilic by a surfactant are treated with a nickel plating bath, a cobalt plating bath, By uniformly suspending in a nickel and / or cobalt-containing plating bath such as a nickel alloy plating bath or a cobalt alloy plating bath and performing electric composite plating, the wear resistance and slidability of the plating film are improved. The present invention has been newly found and the present invention has been completed. In the method of the present invention, it was also found that the effect is remarkably improved by further containing the ceramic fine particles dispersed in the plating bath.

The method for producing a composite plated metal material having excellent wear resistance and slidability according to the present invention contains at least one metal selected from nickel and cobalt on a clean surface of a substrate made of a metal material. When performing electroplating with a plating bath, polytetrafluoroethylene fine particles whose surface has been hydrophilized with a surfactant are dispersed and suspended in the plating bath, and the plating metal and the plating metal are added to the suspension. It is characterized in that the polytetrafluoroethylene fine particles are co-deposited, whereby a metal plating film containing the polytetrafluoroethylene fine particles dispersed therein is formed on the surface of the substrate.

In the method of the present invention, if necessary, ceramic fine particles are further dispersed and suspended in the plating bath, and the plating metal, the polytetrafluoroethylene fine particles, and the ceramic fine particles are deposited on the surface of the substrate by the plating bath. May be co-deposited, whereby a metal plating film containing the polyethylene tetrafluoroethylene fine particles and the ceramic fine particles dispersed therein may be formed on the surface of the substrate.

In the above method of the present invention, it is preferable that the plating bath further contains a cationic surfactant as a co-deposition aid.

[0009]

There is no particular limitation on the metal material used as the substrate in the method of the present invention. For example, an iron-based metal material selected from carbon steel, stainless steel, chrome molybdenum steel, aluminum, aluminum alloy, copper and copper. It can be selected from non-ferrous metal materials selected from alloys, titanium, titanium alloys, magnesium, magnesium alloys and the like.

In the method of the present invention, the metal forming the matrix of the metal plating film contains nickel and / or cobalt, and nickel, nickel alloys (for example, nickel-phosphorus alloys, nickel-iron alloys, etc.), Cobalt and cobalt alloys (eg cobalt-
Nickel alloy, cobalt-boron alloy, etc.).

Hydrophilic PT used in the method of the present invention
The FE fine particles are obtained by subjecting the surface of the PTFE fine particles to a hydrophilic treatment using a surfactant, and it is preferable to use a nonionic surfactant as the hydrophilizing agent. The hydrophilic PTFE fine particles preferably have an average particle diameter of 0.5 to 10 μm. Hydrophilic P in plating bath
There is no particular limitation on the concentration of TFE particles added, but 20 g
/ Liter or more is preferable. This concentration is 20
If it is less than g / liter, the content of the hydrophilic PTFE fine particles contained in the metal plating film is so small that the resulting composite plated metal material has insufficient slidability and wear resistance. In the method of the present invention, a nickel plating bath, a cobalt plating bath, a nickel alloy plating bath or a cobalt alloy plating bath is used as the plating bath. There is no limitation on the composition of the plating bath.

In the method of the present invention, it is preferable to use a cationic surfactant as a co-deposition aid for hydrophilic PTFE. The type and chemical structure of the cationic surfactant are not particularly limited, but for example, amine type, quaternary ammonium salt type, or polyvinyl pyridine type cationic surfactant can be used.

When a cationic surfactant is used as a co-deposition aid, its concentration in the plating bath is 0.05.
It is preferably from 10 g / liter. If this concentration is less than 0.05 g / liter, the effect of the cationic surfactant used as a co-deposition aid becomes insufficient and the content of PTFE fine particles in the obtained metal plating film becomes small, which is not preferable. . When it exceeds 10 g / liter, the eutectoid effect is saturated. The more preferable concentration of the cationic surfactant in the method of the present invention is 0.1 to 5 g / liter.

Further, in the method of the present invention, the ceramic fine particles may be dispersed and suspended together with the hydrophilic PTFE fine particles in the plating bath. Examples of such ceramic fine particles include SiC, BN, Si ₃ N ₄ , WC and TiC. , TiO
It is possible to use at least one selected from fine particles such as ₂ , Al ₂ O ₃ , ZrB ₂ , diamond and CrB, and these may be selected and used from those currently used for dispersion plating. However, it is necessary to select the ceramic fine particles in consideration of the influence of the composite plated metal material on the strength of the mating material. For example, when the mating material is a hard material such as stainless steel, Si
It is most preferable to use ceramic particles having high hardness such as C and TiC. On the contrary, when the mating material is a material having a low strength such as aluminum, the mating plated metal film in which the ceramic fine particles having high hardness and the PTFE fine particles are simultaneously contained causes large wear and damage to the mating material. It is hard to say that such a composite plated metal film is an ideal plated film for sliding parts. In such a case, it is preferable to use a solid lubricant such as MoS ₂ or BN. Generally, it is preferred that the ceramic particles have an average particle size of less than 5 μm. This is because when the average particle size of the ceramic fine particles is 5 μm or more, the lubricating and sliding effect of the PTFE fine particles becomes insufficient and the mating material may be worn.

The concentration of the ceramic fine particles added to the plating bath is 100 to 120 g / liter in the conventional composite plating bath in which the fine ceramic particles are dispersed.
In the method of the present invention, the concentration of the ceramic fine particles may not be so high, and considering the combined use of the PTFE fine particles, the concentration of the ceramic fine particles may be about 60 g / liter or higher.

In the method of the present invention, the content of the PTFE fine particles and, if necessary, the ceramic fine particles contained in the obtained plating film is not only the addition concentration of the PTFE fine particles in the plating bath, but also the current density and the surface activity. It can be adjusted depending on the concentration of the agent added.

Furthermore, by adjusting the current density in the plating process, for example, PTF may be formed near the surface of the plating film.
A large amount of E fine particles can be co-deposited, and a plating film having a gradient distribution in which the distribution density of the PTFE fine particles gradually decreases from the surface of the plating film toward the surface of the substrate can be formed from a single plating bath.

The carbon (C) -fluorine (F) bond, which is a constituent of PTFE, has a short bond distance, is chemically inert, and is extremely stable. In addition, PTFE has a high melting point (327
C.), its solid structure is very dense due to the short C—F bond distance, is less susceptible to polarization, and has low free energy. Therefore, PTFE has a low friction coefficient, self-lubricating property, non-adhesive property, water and oil repellency, and low sliding property. Therefore, the metal plating film obtained by the method of the present invention and in which the PTFE fine particles are co-deposited in a dispersed state can exhibit good slidability in a sliding test.

Further, as shown in FIG. 1, the metal material substrate 1
The conventional nickel plating film, cobalt plating film, nickel alloy plating or cobalt alloy plating film 2 which is formed on and does not contain PTFE fine particles may be destroyed when lubricating oil runs out on the surface. . However, as shown in FIGS. 2 and 3, in the composite plating film 4 of the present invention in which the PTFE fine particles 3 are dispersed and co-deposited in the metal plating film (matrix) 2, the PTFE itself has. Due to its self-lubricating property, it suppresses friction with the sliding mating material, and new PTFE particles appear on the surface even if a small amount of the plating film is ground during sliding, so it is possible to maintain high self-lubricating property. It is possible, by this, nickel sliding film, cobalt plating film,
It is also possible to prevent destruction of the nickel alloy plating or cobalt alloy plating film. Depending on the mating material, as shown in Fig. 2, the PTF in the plating film
The distribution distribution density of the E fine particles may be made substantially uniform, or, as shown in FIG. 3, the distribution distribution density of the PTFE fine particles may be gradually increased toward the plating film surface.

On the other hand, as shown in FIG. 4, a conventional composite plating film, that is, SiC, BN, Si ₃ N ₄ , W
C, TiC, TiO ₂ , Al ₂ O ₃ , ZrB ₂ and Cr
The conventional composite plating film 6 containing the ceramic fine particles such as B dispersed therein has a small amount of lubricating oil accumulation due to the ceramic fine particles, but has a good slidability in an unlubricated environment where no lubricating oil exists. I can't expect to show it. However, in the composite plating film 7 of the present invention as shown in FIG. 5, the PTFE fine particles 3 and the SiC, B
N, Si ₃ N ₄ , WC, TiC, TiO ₂ , Al
_Since the ceramic fine particles 5 such as ₂ O ₃ , ZrB ₂ and CrB are dispersedly contained in the metal plating film (matrix) 2, the composite plating film 7 also has the effect of the PTFE fine particles 3 and the ceramic fine particles 5. Therefore, good wear resistance and slidability can be exhibited. The lubrication mechanism in this case is considered to be due to the self-lubricating property of the PTFE fine particles.

The conventional electroless PTFE dispersion composite plating film requires a long-time treatment to increase the plating thickness, and it is not possible to form a film having an inclined distribution density of PTFE fine particles in a short time. In addition, since PTFE fine particles are co-deposited on the interface between the metal material substrate and the plating film, the adhesion between the substrate and the plating film is slightly insufficient, and further, the life of the plating bath is short. Therefore, the composite plating film characteristics obtained by the method of the present invention cannot be expected.

[0022]

EXAMPLES The present invention will be described in detail below with reference to examples and comparative examples. Examples 1 to 6 and Comparative Examples 1 to 4 In each of Examples 1 to 6 and Comparative Examples 1 to 4, a composite plated metal material was manufactured under the following conditions.

1. Complex plating film preparation conditions (1) Base material to be plated: (A) Aluminum alloy: J
IS-A5052, (B) Stainless Steel: JIS-SU
S304

(2) Plating bath composition: (1) Ni plating bath (Ni bath) Nickel sulfamate (60 wt.%): 800 g / liter Nickel chloride (hexahydrate): 15 g / liter Boric acid: 45 g / liter Saccharin Soda: 5 g / liter pH: 4.0-5.0 Plating bath temperature: 55-60 ° C. Current density: 15 A / dm ² Plating treatment time: 20 minutes

(2) Co-P plating bath (Co-P bath) Cobalt sulfamate (60 wt.%): 800 g / liter Cobalt chloride (hexahydrate): 15 g / liter Hypophosphorous acid: 0.5 g / L Boric acid: 45 g / L pH: 4.0-5.0 Plating bath temperature: 55-60 ° C. Current density: 15 A / dm ² Plating treatment time: 10 minutes

(3) Electroless Plating Bath (Comparative Example) Nickel chloride: 16 g / liter Sodium hypophosphite: 24 g / liter Sodium succinate: 16 g / liter Malic acid: 18 g / liter Diethylamine: 10 g / liter pH: 5 .5 Plating bath temperature: 93 ° C

(3) Hydrophilic PTFE fine particle slurry: polyflon dispersion D-1 manufactured by Daikin Industries, Ltd.
(Hydrophilic PTFE slurry, primary particle size 5 μm, secondary particle size 0.3 μm, solid content 60%) (4) SiC particles: Showa Denko, particle size 0.7 μm, 5
μm, 10 μm (5) Surfactant: Sanyo Kasei Co., Ltd., cationic surfactant (NN dimethylaminopolymethacrylate, trademark: Emulmin RP-102, solid content 30%) (6) Cationic surfactant for electroless plating bath : Fluorocarbon FC-135C (trademark) manufactured by Sumitomo 3M

Table 1 shows the composition of the plating bath and the plating conditions.

[0029]

[Table 1]

2. Evaluation test method (1) Bowden friction and wear test Test conditions: vertical load 1 kg, stroke 30 mm, number of repetitions 200 times, room temperature, non-lubricated environment. In addition, S
A UJ-2 ball (diameter = 10 mm) was used.

(2) Measurement of wear depth of base material The wear depth of the plating film was calculated from the measured surface roughness. (3) Measurement of wear amount of mating material The wear scar diameter was measured with a stereoscopic microscope, and the wear amount was calculated from this measured value. (4) Confirmation of PTFE co-deposition amount The distribution of F was analyzed by EPMA for the cross section of the plating film, and the PTFE co-deposition amount was calculated from the result.

Table 2 shows the results of the above evaluation test.

[0033]

[Table 2]

As is clear from the results of Table 2, Example 1
The composite plating films according to the method of the present invention of Nos. 6 to 6 have a low friction coefficient, a small film wear, and excellent wear resistance and slidability, and PTFE fine particles are uniformly dispersed and contained in the composite plating film. Was there. However, the plating films of Comparative Examples 1 to 3 were unsatisfactory in both wear resistance and slidability in a non-lubricated environment.

[0035]

As described above, the composite plating film obtained by the method of the present invention can exhibit excellent self-lubricating property even under sliding conditions in a non-lubricated environment, and at the same time has excellent wear resistance, In addition, it has excellent self-lubricating property. That is, the method of the present invention is effective for forming a composite plating film having an effect of reducing wear and damage of sliding parts on the surface of a metal material substrate.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view of an example of a conventional metal plating film used for a normal sliding portion.

FIG. 2 shows P of the present invention having excellent wear resistance and slidability.
Sectional explanatory drawing of an example of a TFE eutectoid composite plating film.

FIG. 3 is a cross-sectional explanatory view of another example of the composite plating film of the present invention having excellent wear resistance and slidability.

FIG. 4 is an explanatory cross-sectional view of an example of a conventional ceramic fine particle eutectoid composite plating film.

FIG. 5 is an explanatory cross-sectional view of an example of the PTFE and ceramic fine particle eutectoid composite plating film of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Metal material base material 2 ... Metal plating film (matrix metal) 3 ... PTFE fine particles 4 ... PTFE eutectoid composite plating film 5 of the present invention 5 ... Ceramic fine particles 6 ... Conventional ceramic eutectoid composite plating film 7 ... PTFE of the present invention Ceramic eutectoid composite plating film

Claims (3)

[Claims] 1. When performing electroplating on a clean surface of a substrate made of a metal material with a plating bath containing at least one metal selected from nickel and cobalt, the surface of the substrate is hydrophilic by a surfactant in the plating bath. The activated polytetrafluoroethylene fine particles are dispersed and suspended, and the plating metal and the polytetrafluoroethylene fine particles are dispersed and co-deposited on the surface of the substrate by this plating bath, and thereby, on the surface of the substrate. A method for producing a composite plated metal material having excellent slidability and wear resistance, which comprises forming a metal plating film containing the polytetrafluoroethylene fine particles dispersed therein. 2. Ceramic fine particles are further dispersed and suspended in the plating bath, and the plating metal, the polytetrafluoroethylene fine particles, and the ceramic fine particles are co-deposited on the surface of the substrate by the plating bath. The method for producing a composite plated metal material according to claim 1, wherein a metal plating film containing the polyethylene tetrafluoroethylene fine particles and the ceramic fine particles dispersed therein is formed on the surface of the substrate. 3. The method for producing a composite plated metal material according to claim 1, wherein the plating bath further contains a cationic surfactant as a co-deposition aid.