JP2023018763A - Plated film, composite film, sliding component, method for manufacturing plated film, method for manufacturing composite film and method for manufacturing sliding component - Google Patents

Abstract

To provide: a plated film capable of preventing a surface shape increasing the surface area of the plated film from being degraded by a load; a composite film; a sliding component; a method for manufacturing the plated film; a method for manufacturing the composite film; and a method for manufacturing the sliding component.SOLUTION: A plated film 13 provided on the surface of a material 11 to be plated includes: a film part 14 including nickel or nickel alloy; and insulator or semiconductor inorganic compound particles 15 positioned in the inside of the film part 14. The surface of the film part 14 includes a smooth part 14A following the surface of the material 11 to be plated and a depression part 14B having a shape following at least a part of the appearance of the inorganic compound particle 15.SELECTED DRAWING: Figure 1

Description

The present invention provides a plating film containing nickel or a nickel alloy, a composite film containing the plating film, a sliding component comprising the composite film, a method for producing the plating film, a method for producing the composite film, and a method for producing the sliding component. Regarding.

In the field of surface treatment technology, nickel or nickel alloy plating is used for the purpose of improving wear resistance and corrosion resistance. The increase in the surface area of the plating film improves the adhesion strength when the resin adheres to the plating film, improves the adhesion with the coating film, increases the amount of catalysts and lubricants carried, and improves the solderability during soldering. Realize improvement. One example of a technique for increasing the surface area of a plated film is to immerse a Ni—P (nickel-phosphorus) plated film in acid to form micropores in the plated film (see, for example, Patent Document 1).

JP-A-1-191789

On the other hand, in the method of immersing the plating film in acid, the entire surface of the plating film is roughened and tapered protrusions are scattered over the entire surface. When a load is applied to a plated film manufactured by such a method, the load concentrates on the tapered convex portions scattered on the surface, which impairs the irregular shape. As a result, there is a risk that the resin, coating film, etc., provided on the surface of the plating film will peel off from the plating film.

The plating film for solving the above problems is a plating film provided on the surface of a material to be plated, comprising a film portion containing nickel or a nickel alloy, and an insulator or semiconductor inorganic material located inside the film portion. compound particles, and the surface of the film portion includes a smooth portion that follows the surface of the material to be plated, and a concave portion having a shape that follows at least a part of the outer shape of the inorganic compound particles.

According to the above configuration, since the surface of the coating portion is provided with the recesses, the surface area of the coating portion is increased compared to the surface of the coating portion without the recesses. As a result, it is possible to improve adhesive strength when resin is adhered to the plating film, improve adhesion with the coating film, increase the amount of catalysts and lubricants supported, and improve solderability during soldering. . In addition, since the surface of the film portion has a smooth portion that follows the surface of the material to be plated, for example, compared to the case where the surface of the plating film is dotted with convex shapes that do not follow the surface of the material to be plated, The load applied to the surface of the coating is distributed over a larger area. Thereby, deterioration of the surface shape of the plating film can be suppressed.

In the plating film, the recesses have a depth of 1 μm or more with respect to the smooth portion, and the number of recesses in the cross section of the plating film including the thickness direction of the plating film is the same as that of the film portion. It is preferable that the number is 1 or more and 100 or less per 100 μm in the one-dimensional direction along the surface, and the total opening width of the recesses is 2 μm or more and 50 μm or less per 100 μm in the one-dimensional direction. Moreover, in the plating film, it is preferable that the surface area of the concave portion is 2% or more and 50% or less on the surface of the film portion. According to each of the above configurations, on the surface of the film portion, the surface area of the plated film can be increased by the recesses while appropriately suppressing deterioration of the surface shape of the plated film by ensuring a sufficient area of the smooth portion. .

A composite film for solving the above problems includes any of the plating films described above and a surface layer composed of a lubricant located on the surface of the plating film. According to the above configuration, by providing a surface layer made of a lubricant on the surface of the plating film having the smooth portion and the concave portions, the slidability in the smooth portion can be enhanced. In addition, even when the lubricant on the smooth portion decreases due to sliding, the lubricant filled in the recesses is supplied to maintain the sliding performance of the plating film surface. In addition, the holding power of the lubricant can be enhanced by the concave portions on the plating film.

In the above composite coating, the surface layer preferably contains a layered lattice structure as the lubricant. A lubricant containing a layered lattice structure is less likely to reduce the solid lubricant from the surface of the plated film during sliding, compared to other solid lubricants, liquid lubricants, and semi-solid lubricants. Therefore, by including the layered lattice structure as a lubricant in the surface layer, even when the part provided with the composite film slides against another part, the sliding performance can be preferably maintained.

A sliding component for solving the above problems is provided with any one of the above composite coatings, the surface of the composite coating being in sliding contact with a sliding object. According to the above configuration, the surface of the sliding component is provided with the composite coating in which the surface layer composed of the lubricant containing the layered lattice structure is provided on the plating coating having the coating portion having the smooth portion and the concave portion. Therefore, the sliding performance of the sliding parts can be improved.

A method for producing a plating film for solving the above problems is to use a plating solution in which a nickel component is dissolved and inorganic compound particles of an insulator or a semiconductor are dispersed, by an electroless plating method or an electroplating method. By depositing a coating containing nickel or a nickel alloy derived from a nickel component on the surface of a material to be plated, a plating film in which the inorganic compound particles codeposit on the inside and surface of the coating is formed on the surface of the material to be plated. and the plating film is contacted with a solution in which the inorganic compound particles are soluble and the film portion is insoluble, thereby dissolving the inorganic compound particles present on the surface of the plating film. and a second step of forming a recess.

According to the above manufacturing method, in the first step, a plating film containing a film portion and inorganic compound particles is formed on the material to be plated, and in the second step, the inorganic compound particles present on the surface of the plating film are dissolved. . As a result, recesses having a shape following the outer shape of the inorganic compound particles are formed on the surface of the plating film where the inorganic compound particles are present. As a result, it is possible to improve the adhesive strength when bonding resin to the plating film, improve the adhesion to the coating film, increase the amount of supported catalysts and solid lubricants, and improve solderability during soldering. becomes. In addition, a smooth portion, which is a smooth surface, is formed on a portion of the surface of the plating film where no inorganic compound particles are present. As a result, the load applied to the surface of the film portion is dispersed over a larger area than, for example, when the surface of the plating film is dotted with convex shapes that do not follow the surface of the material to be plated. Therefore, deterioration of the surface shape of the plated film can be suppressed.

A method for producing a composite film for solving the above problems is to form the plating film on the surface of a material to be plated using the method for producing a plating film, and then apply a surface layer made of a lubricant to the plating film. form on the surface.

A method of manufacturing a sliding component for solving the above-mentioned problems uses the above-described method of manufacturing a composite coating to form the composite coating on the surface of the sliding component.

According to the present invention, deterioration due to load can be suppressed for the surface shape that increases the surface area of the plating film.

FIG. 1 is a cross-sectional view of a sliding component. FIG. 2 is a cross-sectional view of a plating film formed on a material to be plated in the first step in the method of manufacturing a composite film. FIG. 3 is a graph showing the relationship between the angle of the material to be plated with respect to the surface of the plating solution in the first step and the surface area ratio of the inorganic compound particles on the surface of the plating film. FIG. 4 is a cross-sectional view of a plating film from which inorganic compound particles exposed on the surface of the plating film have been removed in the second step of the method for producing a composite film. 1 is an SEM image (secondary electron image) of the surface of a plating film from which inorganic compound particles exposed on the surface of the plating film have been removed in Example 1. FIG. 1 is a binarized SEM image (backscattered electron image) of the surface of a plating film after forming the plating film and before removing the inorganic compound particles in Example 1. FIG. 1 is an SEM image (secondary electron image) of a section of a plating film from which inorganic compound particles exposed on the surface of the plating film have been removed in Example 1. FIG.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 4. FIG.
[Sliding parts]
As shown in FIG. 1, the sliding component 10 is, for example, a component that constitutes an automobile engine, power train, or the like. Specifically, the sliding parts 10 are parts that constitute various industrial products such as engine pistons and cylinders, bearings, shafts as sliding axes, plunger pumps, and washers.

The sliding part 10 includes a material to be plated 11 having a planar, curved, or spherical smooth surface. The material to be plated 11 is, for example, a metal material such as steel, copper alloy, or aluminum alloy. In addition, the material to be plated 11 is not limited to a metal material, and may be a non-metal material such as glass or resin.

A composite film 12 is provided on the surface of the material 11 to be plated. The surface of the composite film 12 is a surface that comes into sliding contact with an arbitrary sliding object. The composite film 12 includes a plated film 13 positioned on the surface of the material to be plated 11 and a surface layer 16 positioned on the surface of the plated film 13 .

[Plating film]
The plating film 13 is a layer formed by electroless plating or electroplating, for example. The plated film 13 includes a film portion 14 containing nickel or a nickel alloy, and inorganic compound particles 15 which are particles having a different component from the film portion 14 . A plating solution used for forming the plating film 13 contains a nickel component and inorganic compound particles 15 . A plating method for forming the plating film 13 is co-deposition of the film portion 14 and the inorganic compound particles 15 . The eutectoid forming the plating film 13 causes the inorganic compound particles 15 to be incorporated into the surface and inside of the film portion 14 while depositing the film portion 14 derived from the nickel component on the surface of the material to be plated 11 . The plating thickness of the plating film 13 is, for example, 3 μm or more and 30 μm or less, but may be less than 3 μm or more than 30 μm.

The surface of the coating portion 14 includes a smooth portion 14A and recesses 14B.
The smooth portion 14A follows the surface of the material 11 to be plated. The smooth portion 14A is a surface that is as smooth as the surface of the material 11 to be plated or smoother than the surface of the material 11 to be plated. The smooth portion 14A is one surface of the surface of the coating portion 14 that is not divided into the recesses 14B. The surface of the coating portion 14 has a sea-island structure in which the smooth portion 14A is the sea and the concave portion 14B is the island.

The concave portion 14B has a shape following at least part of the outer shape of the inorganic compound particles 15 . For example, when the inorganic compound particles 15 are crystalline, the outer shape of the inorganic compound particles 15 has crystal planes unique to the inorganic compound particles 15 . When the outer shape of the inorganic compound particles 15 has crystal planes, the planes defining the recesses 14B include planes reflecting the crystal planes of the inorganic compound particles 15 . When the inorganic compound particles 15 are amorphous spherical bodies, the outer shape of the inorganic compound particles 15 has a small spherical surface. When the outer shape of the inorganic compound particle 15 has a spherical surface, the surface defining the concave portion 14B has a spherical surface that reflects at least part of the spherical surface of the inorganic compound particle 15 . When the inorganic compound particle 15 is a needle-like body having a tapered outer surface, the surface that separates the recess 14B has a tapered shape that reflects at least part of the tapered outer surface of the inorganic compound particle 15 .

The concave portions 14B are formed by removing the inorganic compound particles 15 codeposited with the smooth portions 14A from the surface of the coating portion 14 in the formation of the plated coating 13 . The configuration in which the surface of the coating portion 14 includes the concave portions 14B increases the surface area of the coating portion 14 compared to the configuration in which the surface of the coating portion 14 does not include the concave portions 14B. In addition, since the load applied to the coating portion 14 is received by the smooth portion 14A, the load can be dispersed over a larger area than when the surface of the coating portion 14 has a tapered convex shape. Deterioration of the surface shape is suppressed.

The inorganic compound particles 15 are particles that have low solubility in the pH range of the plating solution and do not interfere with the formation of the plating film 13 even when dissolved in the plating solution. The inorganic compound particles 15 are non-conductive insulator or semiconductor particles that do not contribute to the deposition of the film portion 14 because the inorganic compound particles 15 are not charged when the plating film 13 is formed. In this embodiment, a weakly acidic plating solution having a pH range of approximately 4.0 to 6.0 is used. The inorganic compound particles 15 are soluble in an acidic solution or an alkaline solution in which the coating portion 14 is insoluble. Inorganic compounds forming the inorganic compound particles 15 are, for example, metal salts, metal hydroxides, and silicon oxides. An example of the metal constituting the metal salt or metal hydroxide is any one selected from the group consisting of calcium, magnesium, strontium, manganese and titanium. Examples of metal salts are phosphates, oxalates and carbonates. Specifically, the material constituting the inorganic compound particles 15 is at least one selected from the group consisting of manganese phosphate, calcium phosphate, strontium phosphate, titanium phosphate, nickel hydroxide, nickel oxalate, and magnesium carbonate. .

The particle diameter of the inorganic compound particles 15 is preferably 20% or more and 200% or less as a 50% particle diameter (median diameter D50) with respect to the required thickness of the plating film 13 . By using the inorganic compound particles 15 having a particle diameter within the above range, the inorganic compound particles 15 can be suitably incorporated during the deposition of the coating portion 14, and are embedded in the coating portion 14 and on the surface of the coating portion 14. The inorganic compound particles 15 that are not exposed can be reduced.

Moreover, the Mohs degree of the inorganic compound particles 15 is preferably comparable to that of pure nickel and nickel alloy, for example, higher than that of pure nickel and lower than that of nickel alloy. For example, the Mohs hardness of pure nickel is about 3.5, the Mohs hardness of a nickel phosphorus alloy, which is an example of a nickel alloy, is about 6, and the Mohs hardness of manganese phosphate, which is an example of the inorganic compound particles 15, is about 5 (typical value ). By using a substance having a Mohs hardness comparable to that of pure nickel and a nickel alloy as the inorganic compound particles 15 , it is possible to suppress increase or decrease in the Mohs hardness of the plating film 13 due to codeposition of the inorganic compound particles 15 . As the inorganic compound particles 15, a substance having a higher Mohs degree than pure nickel and nickel alloy may be used.

[Surface layer]
The surface layer 16 exists on the smooth portion 14A of the coating portion 14 and also fills the inside of the concave portions 14B. The surface layer 16 is made of a lubricant, for example. As the lubricant forming the surface layer 16, any one of a liquid lubricant (eg, lubricating oil), a semi-solid lubricant (eg, grease), and a solid lubricant is used. Solid lubricants include metal oxides, metal hydroxides, metal sulfides, inorganic compounds such as phosphate compounds, soft metals such as tin and lead, and PTFE, which is a resin. Even if the lubricant on the smooth portion 14A is reduced due to sliding, the surface layer 16 is supplied with the lubricant filled in the concave portion 14B, so that the sliding performance of the sliding component 10 is improved. maintained.

When the composite coating 12 is used for the sliding component 10 as in this embodiment, it is preferable to use a solid lubricant containing a layered lattice structure as the surface layer 16 . The layered lattice structure improves sliding performance by cleaving the layered lattice. The layered lattice structure is an example of a solid lubricant such as molybdenum disulfide, tungsten disulfide, graphite, boron nitride, mica, and the like. The layered lattice structure maintains the sliding performance by staying on the smooth portion 14A while deforming even when the sliding part 10 slides on other parts. In other words, the solid lubricant containing the layered lattice structure is more likely to plate than other solid lubricants, liquid lubricants, and semi-solid lubricants when the sliding component 10 slides against other components. The solid lubricant is less likely to decrease from the surface of the film 13 . In addition, even if the solid lubricant containing the layered lattice structure is peeled off from the surface of the plating film 13, it adheres to the surface of the sliding partner and maintains the sliding performance.

[Action of Embodiment]
A method for manufacturing the composite coating 12 will be described below with reference to FIGS. 2 to 4. FIG.
[First step]
As shown in FIG. 2, as a method of manufacturing the composite film 12, first, a first step of forming a plating film 13 on a material to be plated 11 by electroless plating or electroplating is performed. In the first step, the film portion 14 derived from the nickel component contained in the plating solution is deposited on the surface of the material to be plated 11, and the inorganic compound particles 15 are incorporated into the surface and inside of the deposited film portion 14 to eutectoid. do. At this time, since the inorganic compound particles 15 are insulator or semiconductor particles, deposition of the film portion 14 around the inorganic compound particles 15 exposed on the surface of the plating film 13 is suppressed. Therefore, the portion of the surface of the film portion 14 other than the portion where the inorganic compound particles 15 are exposed becomes a smooth portion 14A following the surface of the material 11 to be plated. The plating solution used for each of electroless plating and electroplating in the first step will be described below.

[Electroless plating]
A plating solution used for electroless plating contains inorganic compound particles 15, a nickel component, a reducing agent, a complexing agent, and a pH adjuster. The amount of the inorganic compound particles 15 added is, for example, 0.1 g/L or more and 20 g/L or less, preferably 0.5 g/L or more and 10 g/L or less, and more preferably 1 g/L or more and 5 g/L or less. is. Note that the inorganic compound particles 15 are present in a state of being dispersed in the plating solution without being dissolved in the plating solution.

As the nickel component, a water-soluble nickel compound that is soluble in the plating solution is used. The water-soluble nickel compound is, for example, at least one selected from the group consisting of nickel sulfate, nickel chloride, nickel sulfamate, and nickel hypophosphite. In particular, nickel sulfate is preferable because it has good solubility in the plating solution. The concentration of the nickel component is, for example, 0.5 g/L or more and 50 g/L or less.

The reducing agent is, for example, at least one selected from the group consisting of hypophosphorous acid, hypophosphite (sodium salt, potassium salt, ammonium salt), dimethylamine borane, and hydrazine. The concentration of the reducing agent is, for example, 0.01 g/L or more and 100 g/L or less.

Complexing agents include, for example, monocarboxylic acids, dicarboxylic acids, hydroxycarboxylic acids, aminopolycarboxylic acids, ethylenediaminediacetic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, and their ammonium, potassium and sodium salts. At least one selected from the group consisting of Monocarboxylic acids are, for example, acetic acid or formic acid. Dicarboxylic acids are, for example, malonic acid, succinic acid, adipic acid, maleic acid, fumaric acid. Hydroxycarboxylic acids are, for example, malic acid, lactic acid, glycolic acid, gluconic acid, citric acid. Aminopolycarboxylic acids are, for example, ethylenediaminetetraacetic acid and diethylenetriaminepentaacetic acid. Phosphonic acids, amino acids and the like may also be used as complexing agents. The concentration of the complexing agent is, for example, 5 g/L or more and 180 g/L or less.

The pH adjuster is, for example, at least one selected from the group consisting of inorganic acids such as sulfuric acid and phosphoric acid, sodium hydroxide, and aqueous ammonia. The pH range of the plating solution in the electroless plating method is usually 2 or more and 9 or less. In addition, the pH range of the plating solution in the electroless plating method in this embodiment is 4.0 or more and 6.0 or less.

Moreover, various additives may be added to the plating solution. Stabilizers, which are examples of additives, are selected from the group consisting of, for example, lead salts such as lead nitrate and lead acetate, bismuth salts such as bismuth nitrate and bismuth acetate, and sulfur compounds such as thiodiglycolic acid and sodium thiosulfate. is at least one The amount of stabilizer added is, for example, 0.01 mg/L or more and 100 mg/L or less. A pH buffer, which is an example of an additive, is, for example, at least one selected from the group consisting of boric acid, phosphoric acid, phosphorous acid, carbonic acid, sodium salts, potassium salts, and ammonium salts thereof. The amount of buffer added is, for example, 0.1 g/L or more and 200 g/L or less. Surfactants, which are examples of additives, can be used singly or in combination of two or more of various nonionic, cationic, anionic, and amphoteric surfactants. The amount of surfactant added is, for example, 0.1 mg/L or more and 100 mg/L or less.

The plating solution in the electroless plating method of the present embodiment contains 25 g/L nickel sulfate hexahydrate, 25 g/L sodium hypophosphite monohydrate, 20 g/L malic acid, and 10 g/L L sodium acetate, 10 g/L sodium hydroxide, and 10 g/L manganese phosphate. In addition, an optional stabilizer is added to the plating solution so that the bismuth ion in the plating solution is 0.5 mg/L.

[Electroplating]
In the case of the electroplating method, a plating solution such as Watt's bath or nickel sulfamate bath is used. These plating solutions contain a nickel component in addition to the inorganic compound particles 15 . As for the amount of the inorganic compound particles 15 to be added, the same numerical range as in the electroless plating method can be applied even in the electroplating method. Note that the inorganic compound particles 15 are present in a state of being dispersed in the plating solution without being dissolved in the plating solution.

In the case of the Watt bath, the nickel component is, for example, at least one selected from the group consisting of water-soluble nickel compounds such as nickel sulfate hexahydrate, nickel chloride hexahydrate, and nickel carbonate tetrahydrate. Among the water-soluble nickel compounds, nickel sulfate hexahydrate or nickel chloride hexahydrate is preferable in terms of excellent deposition on the material to be plated 11, and nickel sulfate hexahydrate and nickel chloride hexahydrate are preferred. is more preferred. When nickel sulfate hexahydrate and nickel chloride hexahydrate are mixed and used as a nickel component, the amount of nickel sulfate hexahydrate added is 200 g / L or more and 500 g / L or less, and nickel chloride hexahydrate The amount added is preferably 70 g/L or less. In the case of a nickel sulfamate bath, the nickel component is, for example, a water-soluble nickel compound such as nickel sulfamate, nickel chloride hexahydrate, or a mixture thereof.

Various primary brighteners and secondary brighteners may be added to the plating solution. The primary brightener is, for example, at least one selected from the group consisting of saccharin, benzene such as sodium naphthalenesulfonate, derivatives such as naphthalene, sulfonates, and sulfonamides. The secondary brightener is at least one selected from the group consisting of butynediol, propargyl alcohol and coumarin.

The plating solution for the Watt bath in this embodiment is 240 g/L of nickel sulfate hexahydrate, 45 g/L of nickel chloride hexahydrate, 45 g/L of boric acid, and 5 g/L of oxalic acid. and nickel acid dihydrate particles. Other brightening agents may include 2 g/L or less of saccharin and 0.2 g/L or less of butynediol. Moreover, the pH range of the plating solution is 4.0 or more and 4.5 or less.

The plating solution for the nickel sulfamate bath in this embodiment is composed of 450 g/L nickel sulfamate tetrahydrate, 15 g/L nickel chloride hexahydrate, 30 g/L boric acid, and 5 g/L and nickel oxalate dihydrate particles. Moreover, the pH range of the plating solution is 4.0 or more and 4.5 or less.

[Method for controlling the amount of eutectoid of inorganic compound particles]
Here, with reference to FIG. 3, a method for controlling the amount of co-precipitation of the inorganic compound particles 15 onto the plating film 13 in the first step will be described. The horizontal axis of the graph 100 shown in FIG. 3 represents the angle of the material to be plated 11 with respect to the surface of the plating solution. The angle of the horizontal axis is 0 degrees when the surface of the plating solution and the material to be plated 11 are parallel, and 90 degrees when the surface of the plating solution and the material to be plated 11 are perpendicular. The vertical axis of the graph 100 represents the surface area ratio of the inorganic compound particles 15 on the surface of the plating film 13 formed in the first step, that is, the surface of the plating film 13 before the inorganic compound particles 15 exposed on the surface are removed.

A curve 101 in the graph 100 indicates the surface area ratio of the inorganic compound particles 15 in the plating film 13 formed by the electroless plating method. A curve 102 in the graph 100 indicates the surface area ratio of the inorganic compound particles 15 in the plating film 13 formed by electroplating. The concentration of the inorganic compound particles 15 in the plating solution is 2.0 g/L for both curves 101 and 102 .

As shown in the graph 100, the surface area ratio of the inorganic compound particles 15 on the surface of the plating film 13 varies with the increase in the angle of the material to be plated 11 with respect to the liquid surface of the plating solution in both the electroless plating method and the electroplating method. decreased accordingly. Therefore, by controlling the angle of the material to be plated 11 with respect to the liquid surface of the plating solution, the surface area ratio of the inorganic compound particles 15 on the surface of the plating film 13, that is, the amount of codeposition of the inorganic compound particles 15 in the plating film 13 is controlled. can.

Specifically, the angle of the material to be plated 11 with respect to the surface of the plating solution should be 0 degrees or more and 90 degrees or less, and more preferably 15 degrees or more and 80 degrees or less. By setting the angle of the material to be plated 11 with respect to the surface of the plating solution within the above range, the inorganic compound particles 15 can be favorably co-deposited in the plating film 13 . If the angle of the material to be plated 11 with respect to the surface of the plating solution exceeds 90 degrees, the inorganic compound particles 15 may not codeposit in the plating film 13 .

[Second step]
As shown in FIG. 4, a second step is performed in which the plating film 13 formed on the material to be plated 11 in the first step is brought into contact with a treatment liquid in which the inorganic compound particles 15 are soluble and the coating portion 14 is insoluble. As a result, the inorganic compound particles 15 exposed on the surface of the plating film 13 are dissolved, thereby forming the recesses 14B having a shape following at least a part of the outer shape of the inorganic compound particles 15 .

The treatment liquid used in the second step is a solution containing an acid component, either an organic acid or an inorganic acid. Inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, and chromic acid are preferable as the acid component contained in the treatment liquid, from the viewpoints that the coating portion 14 is less likely to be corroded and the inorganic compound particles 15 are quickly dissolved. The pH range of the treatment liquid is 2.0 or less, preferably 1.0 or less. As a method for contacting the plating film 13 with the treatment liquid, an immersion method or a spray method can be applied. In this embodiment, an immersion method is used. The concentration of the acid component in the treatment liquid is, for example, 0.1% by mass or more and 10% by mass or less. Moreover, the treatment conditions in the second step are, for example, a contact time of 30 seconds or more and 600 seconds or less and a temperature of 10° C. or more and 80° C. or less.

The shape of the recesses 14B depends on the extent to which the inorganic compound particles 15 are exposed from the film portion 14 on the surface of the plating film 13 . That is, the recess 14B has various shapes, such as an opening narrower than the inside, an opening the same size as the inside, or an opening wider than the inside. In particular, in the present embodiment, the recess 14B having an opening narrower than the inside can be formed, so that the material forming the surface layer 16 can be favorably supported.

The area ratio of the concave portion 14B on the surface of the coating portion 14 is preferably 2% or more and 50% or less, and more preferably 5% or more and 40% or less. When the area ratio of the concave portions 14B on the surface of the coating portion 14 is within the above range, the surface area of the coating portion 14 can be increased by the concave portions 14B while sufficiently securing the area of the smooth portion 14A.

In the cross section of the plating film 13 including the thickness direction of the plating film 13, the number of the concave portions 14B having a depth of 1 μm or more with respect to the smooth portion 14A is 1 per 100 μm in the one-dimensional direction along the surface of the coating portion 14. More than 100 pieces or less are preferable. Moreover, it is more preferable that the number is 2 or more and 50 or less per 100 μm. In the cross section of the plating film 13, the total opening width of the concave portions 14B having a depth of 1 μm or more with respect to the smooth portion 14A is 2 μm or more and 50 μm or less per 100 μm in the one-dimensional direction along the surface of the coating portion 14. It is preferably 5 µm or more and 40 µm or less. In the cross section of the plating film 13, in the one-dimensional direction along the surface of the film part 14, the number of recesses 14B per 100 μm and the sum of the opening widths are within the above range, so that the area of the smooth part 14A is sufficiently secured. , the surface area of the coating portion 14 can be increased by the concave portions 14B.

[Third step]
Finally, the third step is performed to form the surface layer 16 on the plated film 13 in which the concave portions 14B are formed in the second step. In this embodiment, a surface layer 16 composed of a solid lubricant containing a layered lattice structure is formed on the plated film 13 . Specifically, a dispersion in which particles of a layered lattice structure are dispersed in a solvent made of water or an organic solvent is applied to the surface of the plating film 13 by a method such as brushing, immersion, or spraying, and then the solvent is evaporated by heating. Then, the surface layer 16 is formed. The dispersion may contain a resin or the like as a binder in addition to the particles of the layered lattice structure. Alternatively, the particles themselves of the layered lattice structure may be directly adhered to the surface of the plating film 13 by brush coating, dipping, spraying, or the like. As a result, a composite film 12 including the plating film 13 and the surface layer 16 is formed on the surface of the material 11 to be plated.

[Effects of Embodiment]
According to the above embodiment, the following effects can be obtained.
(1) Since the surface of the coating portion 14 is provided with the concave portion 14B, the surface area of the coating portion 14 is increased as compared with a structure in which the surface of the coating portion 14 is not provided with the concave portion 14B. As a result, the holding power of the lubricant forming the surface layer 16 is improved and the amount of the lubricant carried is increased. In addition, the load applied to the coating portion 14 can be dispersed by the smooth portion 14A having a larger area than in the case where the surface of the coating portion 14 has a tapered convex shape. Thereby, deterioration of the surface shape of the plating film 13 can be suppressed. Therefore, the effect of the recess 14B can be favorably maintained.

(2) By controlling the surface area ratio of the recesses 14B, the number of the recesses 14B in the cross section, and the sum of the opening widths, the area of the smooth parts 14A is sufficiently secured, and deterioration of the surface shape of the plating film 13 is preferably suppressed. At the same time, the surface area of the plating film 13 can be increased by the recesses 14B.

(3) By providing the surface layer 16 made of a lubricant on the surface of the plating film 13, the sliding performance of the sliding component 10 can be improved. Moreover, even if the lubricant on the smooth portion 14A decreases due to sliding, the lubricant filled in the concave portion 14B is supplied to the smooth portion 14A, so the sliding performance of the sliding component 10 is maintained.

(4) By using a solid lubricant containing a layered lattice structure as the surface layer 16, the layered lattice structure is less likely to decrease from the surface of the plated film 13 during sliding, so that the sliding part 10 can be separated from other parts. The sliding performance can be favorably maintained even when sliding.

(5) In the first step, the plating film 13 containing the film portion 14 and the inorganic compound particles 15 is formed on the material to be plated 11, and in the second step, the inorganic compound particles 15 exposed on the surface of the plating film 13 are dissolved. be done. As a result, recesses 14B having a shape following the outer shape of the inorganic compound particles 15 can be formed in the portions of the surface of the plating film 13 where the inorganic compound particles 15 are exposed. In addition, a smooth portion 14A, which is a smooth surface, can be formed on a portion of the surface of the plating film 13 where no inorganic compound particles are present.

It should be noted that the above embodiment can be implemented with the following modifications.
- The lubricant that constitutes the surface layer 16 is not limited to solid lubricants containing layered lattice structures, and may be other solid lubricants, liquid lubricants, and semi-solid lubricants. Even in this case, the above effect (3) can be obtained.

- The composite film 12 can also be applied to applications other than the sliding component 10 . Therefore, as long as the surface layer 16 is provided on the plating film 13, the material of the surface layer 16 is not limited to lubricants, and any material such as molding resin, various coatings, catalysts, solder, etc. can be used. good too. In this case, the adhesive strength is improved by the anchor effect when the resin adheres to the plated film 13, the adhesion between the plated film 13 and the coating film is improved, the amount of catalyst supported is increased, and the solder is improved by improving wettability during soldering. It is possible to achieve improvement in attachability and the like.

If the area of the smooth portion 14A can be sufficiently secured and the surface area of the plating film 13 can be increased by the recesses 14B, the area ratio of the recesses 14B on the surface of the film portion 14 is 2% or more and 50%. It is not limited to below, and may be more than 50%, for example. Similarly, in the cross section of the plating film 13, the number of recesses 14B may be more than 100 per 100 μm in one-dimensional direction along the surface of the film portion 14, and the total opening width of the recesses 14B may be more than 50 μm per 100 μm.

- Various plating films may be provided as a base between the material to be plated 11 and the plating film 13 . For example, when a sufficiently thick plating film is required with respect to the particle diameter of the inorganic compound particles 15, using a plating solution that does not contain the inorganic compound particles 15, the inorganic compound particles 15 are used between the material to be plated 11 and the plating film 13. A plating film of the same type as the film portion 14 that does not contain may be provided. In this case, the plating film that does not contain the inorganic compound particles 15 provided between the material to be plated 11 and the plating film 13 can prevent the concave portion 14B from reaching the material to be plated 11 . The plated film provided between the material to be plated 11 and the plated film 13 may not be the same type of plated film as the film portion 14 .

[Example]
Examples 1 to 8 and Comparative Examples 1 to 6 of the present invention are described below. In addition, each example and each comparative example do not limit said embodiment.

[Base material and plating pretreatment]
In Examples 1 to 8 and Comparative Examples 1 to 6, a cold-rolled steel plate SPCC-SB (manufactured by Paltec Co., Ltd.) of 50 mm×50 mm×t3.0 mm was used as the base material. In addition, as a pre-plating step, the surface of the substrate was cleaned in the order of alkali degreasing, deionized water washing, electrolytic degreasing, deionized water washing, acid washing (17% hydrochloric acid), and deionized water washing.

[Example 1]
The substrate was immersed in the electroless plating solution being stirred with a stirrer, and electroless plating was performed at 90° C. until the film thickness reached about 5 μm. As the plating solution, a medium-high phosphorous type electroless nickel plating solution “SE-666” (manufactured by Nippon Kanigen Co., Ltd.) was added with 2 g/L of manganese phosphate particles “PL-55A” (manufactured by Nihon Parkerizing Co., Ltd.). board. Thereafter, the plated film was immersed in 15% hydrochloric acid at room temperature for 30 seconds to dissolve and remove the manganese phosphate particles co-precipitated on the plated film surface, followed by washing with water and drying.

[Example 2]
Electroless plating was carried out in the same manner as in Example 1 except that 0.5 g/L of titanium phosphate particles (manufactured by Fujimi Incorporated) were added instead of the manganese phosphate particles. Thereafter, the titanium phosphate particles codeposited on the surface of the plating film were removed by dissolution in the same manner as in Example 1, followed by washing with water and drying.

[Example 3]
Electroless plating was carried out in the same manner as in Example 1, except that 4 g/L nickel hydroxide particles (manufactured by Junsei Chemical Co., Ltd.) were added in place of the manganese phosphate particles. Thereafter, nickel hydroxide codeposited on the surface of the plating film was removed by dissolution in the same manner as in Example 1, followed by washing with water and drying.

[Example 4]
Add 5 g/L of nickel oxalate dihydrate particles (manufactured by Yoneyama Yakuhin Kogyo Co., Ltd.) to a Watts bath, immerse the substrate while stirring with a stirrer, and apply a direct current with a current density of 2 A/dm ² at 50 ° C. The solution was electroplated until the film thickness was about 5 μm. The Watts bath contained 280 g/L nickel sulfate, 40 g/L nickel chloride, and 20 g/L boric acid and had a pH of 4.5. After that, the nickel oxalate particles co-precipitated on the plated surface were dissolved and removed by immersion in 5% chromic anhydride heated to 70° C. for 600 seconds, followed by washing with water and drying.

[Example 5]
After forming a plating film in the same process as in Example 1, a molybdenum disulfide-containing lubricating paint Defric Coat HMB-2 (manufactured by Kawamura Laboratory) was applied on the plating film so that the dry film thickness was 5 μm. A solid lubricating film was formed.

[Example 6]
After forming a plated film by the same steps as in Example 2, a solid lubricating film was formed on the plated film by the same steps as in Example 5.

[Example 7]
After forming a plated film by the same steps as in Example 3, a solid lubricating film was formed on the plated film by the same steps as in Example 5.

[Example 8]
After forming a plated film by the same steps as in Example 4, a solid lubricating film was formed on the plated film by the same steps as in Example 5.

[Comparative Example 1]
The substrate is immersed in medium-high phosphorous type electroless nickel plating solution "SE-666" (manufactured by Nippon Kanigen Co., Ltd.), electroless plating is performed at 90°C while stirring with a stirrer until the film thickness is about 5 μm, and then washed with water. , dried.

[Comparative Example 2]
After forming a plating film in the same process as in Comparative Example 1, the plated film was immersed in 30% nitric acid at room temperature for 1 minute to form microcracks on the surface of the plating film. Then, it was washed with water and dried.

[Comparative Example 3]
Using a plating solution containing 220 g/L nickel sulfate, 150 g/L nickel chloride, and 20 g/L boric acid, the substrate was immersed while stirring with a stirrer, and the current density was 8 A/dm ² at 50 ° C. It was electroplated by direct current electrolysis. The film thickness was about 1 μm. Then, it was washed with water and dried.

[Comparative Example 4]
After forming a plating film in the same steps as in Comparative Example 1, a solid lubricating film was formed on the plating film in the same steps as in Example 5.

[Comparative Example 5]
After forming a plating film in the same steps as in Comparative Example 2, a solid lubricating film was formed on the plating film in the same steps as in Example 5.

[Comparative Example 6]
After forming a plating film by the same steps as in Comparative Example 3, a solid lubricating film was formed on the plating film by the same steps as in Example 5.

[Recess area ratio evaluation method]
For Examples 1 to 8 and Comparative Examples 1 to 6, the area ratio of recesses on the surface of the plating film was measured by observing SEM images obtained by scanning electron microscope (SEM) of the plating film. As an example, FIG. 5 shows a secondary electron image of the plating film 13 of Example 1 obtained by SEM.

As shown in FIG. 5, in the plated film 13 of Example 1, since the boundary between the smooth portion 14A and the concave portion 14B is clear, the area ratio of the concave portion 14B can be obtained by image analysis. In Example 1, the area ratio of the concave portion 14B was 22%.

In addition, FIG. 6 shows that after forming the plating film 13 of Example 1, the manganese phosphate particles, which are the inorganic compound particles 15 codeposited on the surface of the plating film 13, were lightly washed with #3000 emery paper without dissolving with hydrochloric acid. It is an SEM image (backscattered electron image) after polishing. FIG. 6 is an image obtained by binarizing the backscattered electron image acquired by the SEM using Otsu's binarization method, which is an example of an image analysis method. In FIG. 6, the smooth portion 14A where the film portion 14 composed of the heavy element is exposed appears bright, and the portion where the inorganic compound particles 15 composed of the relatively light element are buried appears dark. In this case, the portion of the inorganic compound particles 15 that appears dark can be regarded as a portion that is dissolved by the treatment liquid to form the concave portion 14B. According to such a method, the area ratio of the concave portion 14B can be obtained more easily. Also, the same effect can be obtained by detecting an element specific to the inorganic compound particles 15 by EDS instead of the backscattered electron image.

[Method for evaluating the number of recessed portions and method for evaluating the opening width of recessed portions]
In Examples 1 to 8 and Comparative Examples 1 to 6, the plated film was filled with resin after electroplating with copper for the purpose of protecting the surface. After that, by processing the cross section including the thickness direction of the plating film so that it can be observed and observing the SEM image of the cross section, the number of recesses having a depth of 1 μm or more per unit length of 100 μm and the opening width was measured. As an example, FIG. 7 shows a secondary electron image when a cross section of the plating film 13 of Example 1 is observed with an SEM. A dashed line 200 in FIG. 7 is a line connecting the ridgelines of the smooth portion 14A. A dashed line 201 in FIG. 7 is a line having the same shape as the dashed line 200, and is a line translated from the dashed line 200 in the direction of the material to be plated 11 by 1 μm.

As shown in FIG. 7, the plating film 13 of Example 1 is provided with a copper plating layer 20 on its surface. In Example 1, the number of concave portions 14B having a depth of 1 μm or more with respect to the smooth portion 14A was 10 per unit length of 100 μm. In addition, the total opening width of the concave portions having a depth of 1 μm or more was 23 μm per unit length of 100 μm.

[Paint film adhesion evaluation method]
For Examples 1 to 4 and Comparative Examples 1 to 3, a coating film having a dry film thickness of 15 μm or more and 20 μm or less was formed by applying a spray paint (manufactured by Asahipen Co., Ltd., water-based multipurpose spray black) on the plating film. . After that, grid-like cut flaws reaching the base material surface were formed with a sharp cutter from above the coating film formed on the plating film. Specifically, 11 cut marks extending in the first direction were formed at intervals of 1 mm, and 11 cut marks extending in the second direction perpendicular to the first direction were formed at intervals of 1 mm. Each cut mark extending in the second direction was formed so as to cross each cut mark extending in the first direction. Then, after a cellophane tape was adhered onto the coating film formed on the plating film, the cellophane tape was peeled off. Then, the number of regions where 50% or more of the coating film was peeled off was measured among the 100 regions partitioned by the grid-like cut marks. Of the 100 regions partitioned by each cut mark, 11 or more regions where the coating film was peeled off by 50% or more were regarded as defective (x), and 1 or more and 10 or less were average (Δ). , and 0 pieces were evaluated as good (○).

[Method for evaluating slidability]
Examples 5 to 8 and Comparative Examples 4 to 6 were evaluated for slidability using a friction test by the ball-on-disk method. SUJ2C with a diameter of 10 mm was used as the spherical test piece. The measurement conditions were a load of 19.6 N, a sliding circle diameter of 10 mm, and a rotation speed of 300 rpm. As an evaluation method, the frictional force during rotation was converted into a coefficient of friction μ, and the time until the coefficient of friction μ exceeded 0.1 was measured. If the time until the coefficient of friction μ exceeds 0.1 is less than 2000 seconds, it will be judged as bad (×). It was rated as good (◯), and those of 6000 seconds or more were rated as best (⊚).

As shown in Table 1, in Examples 1 to 8, the area ratio of the concave portion 14B was 2% or more and 50% or less. In Examples 1 to 8, the number of concave portions 14B per 100 μm in the cross section of the plating film 13 was 1 or more and 100 or less, and the total opening width of the concave portions 14B was 2 μm or more and 50 μm or less per 100 μm. rice field. In contrast, in Comparative Examples 1 and 4, no concave portion was observed. Moreover, in Comparative Examples 2 and 5 and Comparative Examples 3 and 6, recesses were observed on the entire surface of the plating film, and the area ratio of the recesses exceeded 50%. In Comparative Examples 3 and 6, the crystals of the nickel plating layer gave strong orientation to the (1.1.1) plane and (3.1.1) plane, so that the entire surface had a severe uneven shape. A plating film is formed.

In Examples 1 to 4, better results than Comparative Examples 1 to 3 were obtained in the coating film adhesion evaluation. In Comparative Example 1, it is considered that the adhesiveness between the plating film and the coating film was low because there were no concave portions. In Comparative Example 2, it is considered that the plated film itself was degraded by the acid during the formation of the recesses, resulting in separation between the plated film and the base material. In Comparative Example 3, although the area of the recesses was large, the adhesion between the plating film and the coating film was low because the plating film itself defining the recesses had a smooth surface.

Further, in Examples 5-8, better results than Comparative Examples 4-6 were obtained in the slidability evaluation. In Comparative Example 4, since there were no concave portions, the adhesion between the plating film and the solid lubricating film was low. In Comparative Example 5, it is considered that the plated film itself was degraded by the acid during the formation of the recesses, resulting in separation between the plated film and the base material. In Comparative Example 6, it is considered that the solid lubricating film was reduced due to sliding because the plating film itself that defines the recesses had a smooth surface, so that the solid lubricating film could not be maintained by the plating film. Further, in Comparative Examples 5 and 6, in addition to the above reasons, since the area of the concave portion is large and the area of the smooth portion is small, the uneven shape of the surface is damaged due to sliding, and the solid lubricating film cannot be supported. It is considered to be

DESCRIPTION OF SYMBOLS 10... Sliding part 11... Material to be plated 12... Composite film 13... Plating film 14... Film part 14A... Smooth part 14B... Recessed part 15... Inorganic compound particle 16... Surface layer

Claims (9)

A plating film provided on the surface of a material to be plated,
a coating portion containing nickel or a nickel alloy;
Insulator or semiconductor inorganic compound particles located inside the coating,
The surface of the coating portion is
A smooth portion that follows the surface of the material to be plated;
and a concave portion having a shape following at least a part of the outer shape of the inorganic compound particles. The concave portion has a depth of 1 μm or more with respect to the smooth portion,
In the cross section of the plating film including the thickness direction of the plating film,
The number of recesses is 1 or more and 100 or less per 100 μm in a one-dimensional direction along the surface of the coating portion,
2. The plating film according to claim 1, wherein the total opening width of said concave portions is 2 μm or more and 50 μm or less per 100 μm in said one-dimensional direction. The plating film according to claim 1 or 2, wherein the area of the concave portion is 2% or more and 50% or less on the surface of the film portion. A plating film according to any one of claims 1 to 3;
and a surface layer composed of a lubricant located on the surface of the plating film. 5. The composite coating of claim 4, wherein the surface layer includes a layered lattice structure as the lubricant. Equipped with the composite coating according to claim 4 or 5,
A sliding part, wherein the surface of the composite coating is a surface that slides against a sliding object. Using a plating solution in which a nickel component is dissolved and inorganic compound particles of an insulator or a semiconductor are dispersed, a coating portion containing nickel or a nickel alloy derived from the nickel component is formed by an electroless plating method or an electroplating method. A first step of forming a plating film on the surface of the material to be plated, in which the inorganic compound particles codeposit on the inside and surface of the film portion by depositing on the surface of the material to be plated;
A second step of forming recesses by dissolving the inorganic compound particles present on the surface of the plating film by contacting the plating film with a solution in which the inorganic compound particles are soluble and the film portion is insoluble. A method for producing a plating film. After forming the plating film on the surface of the material to be plated using the method for producing a plating film according to claim 7,
A method for producing a composite coating, wherein a surface layer made of a lubricant is formed on the surface of the plating coating. A method for manufacturing a sliding component, wherein the composite coating is formed on a surface of a sliding component using the method for manufacturing a composite coating according to claim 8 .

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