Method for producing plating film, method for producing joined body, plating film, and joined body
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- JAPAN KANIGEN CO LTD
- Filing Date
- 2026-01-19
- Publication Date
- 2026-07-30
Smart Images
Figure JP2026001500_30072026_PF_FP_ABST
Abstract
Description
Method for manufacturing a plating film, method for manufacturing a joined body, plating film, and joined body
[0001] The present disclosure relates to a method for manufacturing a plating film, a method for manufacturing a joined body, a plating film, and a joined body.
[0002] As a joining technique between members, for example, insert molding for integrally molding a metal and a molded resin is known. In insert molding, it is known to increase the joining strength by increasing the surface area of the joining surface of the metal. For example, Patent Document 1 discloses a joined body of a metal and a resin material, characterized in that a plating film having a rough surface structure is provided on the surface of the metal, and the metal and the resin material are integrally joined through the plating film having the rough surface structure.
[0003] Japanese Patent Application Laid-Open No. 2019-151090
[0004] In the joining technique between members as described above, development of a new technique for further increasing the joining strength is still desired. Such a problem is common to joining between members made of arbitrary materials, not limited to joining between a metal and a resin material.
[0005] In one aspect, a method for manufacturing a plating film provided on or on the surface of a plating target material to be joined to another member is provided. The method includes depositing a film portion derived from the metal component on or on the surface of the plating target material by electroless plating or electroplating using a plating solution in which a metal component is dissolved and particles are dispersed, thereby forming a plating film in which the particles are eutectically precipitated inside and on the surface of the film portion; contacting the plating film with a solution to dissolve the particles present on the surface of the plating film in the solution and form recesses on the surface of the plating film; and forming an etching layer including at least one of an oxide of the metal component and a hydroxide of the metal component on the surface of the film portion and having a groove portion recessed in the thickness direction.
[0006] In another embodiment, a method for manufacturing a joined body is provided. The method includes manufacturing a first member having a plating film formed on or on the surface of a material to be plated using the method for manufacturing the plating film, and, after manufacturing the first member, joining a second member to the plating film of the first member.
[0007] In yet another embodiment, a plated film is provided. The plated film is a film provided on or on the surface of a material to be plated to be joined to another member, and comprises a film portion derived from a metal component and particles located inside the film portion, wherein the film portion has an etching layer on its surface containing at least one of the oxide of the metal component and the hydroxide of the metal component, the surface of the etching layer comprises a smooth portion that follows the surface of the material to be plated and a recess having a shape that conforms to at least a part of the outer shape of the particles, and the etching layer has grooves that are recessed in the thickness direction.
[0008] In yet another embodiment, a joint is provided. The joint comprises a first member having a material to be plated and the plating film, and a second member joined to the plating film.
[0009] Figure 1 is a cross-sectional view of the joined body. Figure 2 is a cross-sectional view of the plating film formed on the material to be plated during the plating film formation process. Figure 3 is a cross-sectional view of the plating film after particles exposed on the surface of the plating film have been removed during the recess formation process. Figure 4 is a cross-sectional view of the plating film after an etching layer with grooves has been formed on the surface during the etching process. Figure 5 is a top view of the joined bodies produced in each example and comparative example. Figure 6 is a side view of the joined bodies produced in each example and comparative example. Figure 7 is a table showing the evaluation results for each example and comparative example. Figure 8 is an SEM image of the cross-section of Example 3. Figure 9 is an SEM image of the cross-section of Comparative Example 1.
[0010] Hereinafter, an embodiment of the present disclosure will be described with reference to Figures 1 to 4. [Joint] As shown in Figure 1, the joint 1 comprises a first member 10 and a second member 20. The joint 1 is constructed by integrally joining the first member 10 and the second member 20.
[0011] The first member 10 comprises a material to be plated 11 and a plating film 12. The material to be plated 11 has a smooth surface such as a planar, curved, or spherical surface. The plating film 12 is provided on or on the surface of the material to be plated 11. The plating film 12 only needs to be provided on at least the portion of the material to be plated 11 that contributes to joining with the second member 20.
[0012] Furthermore, "a film is provided on the 'surface' of the object" means that the film is positioned so as to be in contact with the surface of the object. Also, "a film is provided on the 'surface' of the object" means that the film is positioned with any layer (for example, an oxide film or an undercoat) interposed between the surface of the object and the film. In other words, "a film is provided on or on the surface of the object" means that the film may be positioned so as to be in contact with the surface of the object, or any layer may be interposed between the surface of the object and the film. Figure 1 shows an example in which a plating film 12 is provided on the surface of the material to be plated 11.
[0013] The material constituting the material to be plated 11 is not particularly limited as long as it is a material capable of forming a plating film 12 on or on the surface of the material to be plated 11. The material constituting the material to be plated 11 is selected from the group including, for example, metallic materials, polymer materials, ceramic materials, and composite materials thereof. As for metallic materials, there are no particular limitations, but examples include iron and steel (including alloy steel), copper alloys, aluminum alloys, etc. As for polymer materials, there are no particular limitations, but examples include thermoplastic resins and thermosetting resins. Examples of thermoplastic resins include polyethylene, polyamide, polybutylene terephthalate, polyphenylene sulfide, etc. Examples of thermosetting resins include phenolic resins, epoxy resins, silicone resins, etc. As for ceramic materials, there are no particular limitations, but examples include alumina, zirconia, silicon nitride, silicon carbide, etc.
[0014] The plating film 12 is a layer formed, for example, by an electroless plating method or an electroplating method. The plating film 12 comprises a film portion 13 derived from a metal component and particles 16 having a different component from the film portion 13.
[0015] The plating solution used to form the plating film 12 contains a metal component and particles 16. The metal component is not particularly limited, but examples include nickel, chromium, copper, manganese, iron, cobalt, zinc, gallium, palladium, silver, cadmium, indium, tin, platinum, gold, and lead.
[0016] The plating method for forming the plating film 12 is co-deposition of the film portion 13 and particles 16. In co-deposition for forming the plating film 12, when the film portion 13, which originates from the metal component, is deposited on the surface of the material to be plated 11, the particles 16 are incorporated into the surface and interior of the film portion 13. The plating thickness of the plating film 12 is, for example, 3 μm or more and 30 μm or less, but it may be less than 3 μm or greater than 30 μm.
[0017] The coating portion 13 comprises a precipitated metal 14 in which metal components are deposited, and an etching layer 15 located on the surface of the coating portion 13. The etching layer 15 is obtained by chemically etching the surface portion of the precipitated metal 14 that constitutes the coating portion 13. The etching layer 15 contains an oxide of the metal component constituting the precipitated metal 14, or a hydroxide of the metal component, or both. The thickness of the etching layer 15 is, for example, 1 μm or more and 2 μm or less, but may be less than 1 μm or greater than 2 μm.
[0018] The etching layer 15 is provided with grooves 15G that are recessed in the thickness direction. The grooves 15G are formed by selective etching of parts of the deposited metal 14 that are relatively more susceptible to corrosion, such as the grain boundaries of the deposited metal 14, during the chemical etching process when forming the etching layer 15 on the film portion 13.
[0019] The depth of the groove 15G is, for example, 1 μm or more and 2 μm or less, but it may be less than 1 μm or greater than 2 μm. The groove 15G may or may not penetrate the etching layer 15 in the thickness direction. That is, the groove 15G may have a bottom inside the etching layer 15. The depth of the groove 15G can be controlled by adjusting the composition of the etching solution and the contact time of the etching solution when forming the etching layer 15.
[0020] As an example, the etching layer 15 contains 50 to 200 grooves 15G per 100 μm in a one-dimensional direction along the surface of the plating film 12 (for example, the surface of the smooth portion 12A described later) when viewed in cross-sectional view from a viewpoint opposite to the plane including the thickness direction of the plating film 12. The number of grooves 15G in the above-mentioned cross-sectional view can be controlled, for example, by adjusting the crystal grain size of the film portion 13. The crystal grain size of the film portion 13 can be controlled, for example, by adjusting the manufacturing conditions when forming the plating film 12.
[0021] The surface of the plated film 12 comprises a smooth portion 12A and a recess 12B. The recess 12B is formed by removing the particles 16 exposed on the surface of the plated film 12, which is formed by the co-deposition of the film portion 13 and the particles 16. In other words, the recess 12B is the portion from which the particles 16 exposed from the film portion 13 have been removed. Furthermore, the surface of the plated film 12 is formed by the smooth portion 12A and the recess 12B, and the surface of the plated film 12 does not contain particles 16 protruding from the smooth portion 12A.
[0022] The smooth portion 12A and the recessed portion 12B are formed by the surface of the etching layer 15. In the film portion 13, the etching layer 15 is formed along the shapes of the smooth portion 12A and the recessed portion 12B. That is, the etching layer 15 has the shape of a layer along the smooth portion 12A and the recessed portion 12B, and also includes grooves 15G that are recessed in the thickness direction within the layer.
[0023] The configuration in which the surface of the plating film 12 has recesses 12B increases the surface area of the plating film 12 compared to the configuration in which the surface of the plating film 12 does not have recesses 12B. Furthermore, in the configuration in which the surface of the plating film 12 has recesses 12A, the smooth portion 12A receives the load applied to the plating film 12, so the load can be distributed over a larger area compared to the configuration in which the surface of the plating film 12 does not have smooth portions 12A, thus suppressing deterioration of the surface shape of the plating film 12.
[0024] The smooth portion 12A has a shape that conforms to the surface of the material to be plated 11. The recess 12B has a shape that follows at least a part of the outer shape of the particle 16. For example, if the particle 16 is a polyhedron, the recess 12B includes a surface that reflects at least a part of the surfaces of the particle 16 as a polyhedron. If the particle 16 is a spherical body, the recess 12B has a spherical surface that reflects at least a part of the spherical surface of the particle 16 as a spherical body. If the particle 16 is a needle-shaped body with a tapering outer surface, the recess 12B has a tapering shape that reflects at least a part of the tapering outer surface of the particle 16 as a needle-shaped body.
[0025] For example, the recesses 12B have a depth of 1 μm or more relative to the smooth portion 12A. In a cross-sectional view taken from a viewpoint opposite to the plane including the thickness direction of the plated film 12, the number of recesses 12B having a depth of 1 μm or more relative to the smooth portion 12A is preferably 1 to 100 per 100 μm in the one-dimensional direction along the surface of the plated film 12. More preferably, there are 10 to 50 recesses.
[0026] Furthermore, in the cross-sectional view described above, the sum of the opening widths of the recesses 12B having a depth of 1 μm or more relative to the smooth portion 12A is preferably 2 μm to 50 μm per 100 μm in the one-dimensional direction along the surface of the plating film 12, and more preferably 5 μm to 30 μm.
[0027] In the cross-sectional view described above, the sum of the opening widths of the recesses 12B having a depth of 1 μm or more relative to the smooth portion 12A is preferably 2 μm to 50 μm per 100 μm in the one-dimensional direction along the surface of the film portion 13, and more preferably 5 μm to 30 μm. In the cross-section of the plated film 12, by having the number of recesses 12B per 100 μm and the sum of the opening widths within the above range, it is possible to increase the surface area of the plated film 12 with the recesses 12B while sufficiently securing the area of the smooth portion 12A.
[0028] Preferably, the area ratio of recesses 12B on the surface of the plated film 12 is 2% or more and 50% or less, and more preferably 5% or more and 40% or less. By having the area ratio of recesses 12B on the surface of the plated film 12 within the above range, it is possible to increase the surface area of the plated film 12 with the recesses 12B while ensuring a sufficient area of the smooth portion 12A.
[0029] The particles 16 are selected from materials that have low solubility within the pH range of the plating solution and that do not hinder the formation of the plating film 12 even when dissolved in the plating solution. The particles 16 can be inorganic compounds and / or organic compounds that are non-conductive insulators or semiconductors that do not become charged during the formation of the plating film 12 and do not contribute to the deposition of the film portion 13 itself. Examples of inorganic compounds constituting the particles 16 are metal salts, metal hydroxides, and silicon oxides. An example of a metal constituting a 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 metal salts, such as phosphates, oxalates, and carbonates. Specifically, the inorganic compound material constituting the particles 16 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. Examples of organic compound materials constituting the particles 16 include ABS resin (acrylonitrile butadiene styrene resin), AS resin (acrylonitrile styrene resin), polycarbonate resin, polyamide resin, polyester resin, etc. The particles 16 may be surface-treated with surfactants, thickeners, silane coupling agents, etc., as needed. For example, the particles 16 may be surface-treated to prevent secondary aggregation or to prevent dissolution in the plating solution.
[0030] The shape of the particles 16 is not particularly limited as long as they are particulate, but may be any shape such as cube, rectangular prism, polyhedron, perfect sphere, approximate sphere, rod, needle, flake, plate, scale, hollow, or porous. Also, particles 16 having different shapes may be mixed together. The particle diameter of the particles 16 is preferably 20% to 200% of the required thickness of the plating film 12 at the 50% particle diameter (median diameter D50). By using particles 16 having a particle diameter within the above range, the particles 16 can be suitably incorporated during the deposition of the film portion 13, and the amount of particles 16 that are embedded in the film portion 13 and not exposed on the surface of the film portion 13 can be reduced.
[0031] The second member 20 is joined to the plating film 12 of the first member 10. The second member 20 is configured such that a part of it fits into the recesses 12B and grooves 15G of the etching layer 15. As a result, excellent bonding strength is obtained between the first member 10 and the second member 20 through an anchoring effect.
[0032] The material constituting the second member 20 is, for example, a polymer material or a metallic material. The polymer material is not particularly limited, but may be a thermoplastic resin or a thermosetting resin. Examples of thermoplastic resins include polyethylene, polyamide, polybutylene terephthalate, and polyphenylene sulfide. Examples of thermosetting resins include phenolic resin, epoxy resin, and silicone resin. The polymer material may contain inorganic fibers, organic fibers, carbon fibers, metal fibers, or inorganic substances as fillers. The filler content is, for example, 30% to 60%, but may be less than 30% or more than 60%. The metallic material is not particularly limited, but examples include iron and steel (including alloy steel), copper alloys, aluminum alloys, tin, zinc, silver, and bismuth.
[0033] [Manufacturing Method] The manufacturing method of the plating film 12 and the manufacturing method of the joined body 1 will be described below with reference to Figures 2 to 4.
[0034] The method for manufacturing the plating film 12 includes a plating film formation step, a recess formation step, and an etching step. Prior to the plating film formation step, pretreatment of the surface of the material to be plated 11, such as acid degreasing, alkaline degreasing, electrolytic degreasing, or activation treatment, may be performed as needed.
[0035] As shown in Figure 2, in the plating film formation process, a film portion 13 derived from metal components is deposited on or onto the surface of the material to be plated 11, thereby forming a plating film 12 in which particles 16 are co-deposited inside and on the surface of the film portion 13.
[0036] In the plating film formation process, a film portion 13 derived from the metal components contained in the plating solution is deposited by electroless plating or electroplating, and particles 16 are incorporated into the surface and interior of the deposited film portion 13 and co-deposit. The film portion 13 formed in the plating film formation process is composed of deposited metal 14, and no etching layer 15 is formed.
[0037] In this case, the particles 16 are composed of an insulator or semiconductor, which suppresses the deposition of metal components on the exposed surfaces of the particles 16 exposed on the surface of the plating film 12. Furthermore, the parts of the surface of the deposited metal 14 constituting the film portion 13 that are not exposed to the particles 16 become smooth portions 12A that follow the surface of the material to be plated 11.
[0038] In the plating film formation process, the surface area ratio of particles 16 on the surface of the plating film 12, that is, the amount of particles 16 co-deposited in the plating film 12, can be controlled by controlling the angle of the surface of the material to be plated 11 with respect to the surface of the plating solution.
[0039] With the surface of the material to be plated 11 facing upwards, the angle when the surface of the material to be plated 11 is parallel to the surface of the plating solution is defined as 0 degrees, and the angle when the surface of the material to be plated 11 is perpendicular to the surface of the plating solution is defined as 90 degrees. In this case, the surface area ratio of the particles 16 on the surface of the plating film 12 decreases as the angle of the surface of the material to be plated 11 with respect to the surface of the plating solution increases.
[0040] Specifically, the angle of the surface of the material to be plated 11 with respect to the surface of the plating solution may 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 surface of the material to be plated 11 with respect to the surface of the plating solution within the above range, the particles 16 can be suitably co-deposited in the plating film 12. If the angle of the surface of the material to be plated 11 with respect to the surface of the plating solution exceeds 90 degrees, there is a risk that the particles 16 will not co-deposit in the plating film 12.
[0041] As shown in Figure 3, the recess formation step involves contacting the plating film 12 with a processing solution, for example, a solution in which the particles 16 are soluble, thereby dissolving the particles 16 present on the surface of the plating film 12 in the solution and forming recesses 12B on the surface of the plating film 12.
[0042] When the particles 16 exposed on the surface of the plating film 12 dissolve in the solution, a recess 12B is formed that has a shape that conforms to at least a part of the outer shape of the dissolved particles 16. The shape of the recess 12B depends on the extent to which the particles 16 are exposed from the film portion 13 on the surface of the plating film 12. That is, the recess 12B can have various shapes, such as having an opening narrower than the interior, an opening the same size as the interior, or an opening wider than the interior. In particular, in this embodiment, since a recess 12B with an opening narrower than the interior can be formed, the material constituting the second member 20 can be suitably supported.
[0043] When the particles 16 are inorganic compound particles, the treatment solution used in the recess formation step is a solution containing either an organic or inorganic acid. From the viewpoint of rapidly dissolving the particles 16, the acid component in the treatment solution is preferably an inorganic acid such as hydrochloric acid, sulfuric acid, nitric acid, or chromic acid. The pH range of the treatment solution is 2.0 or less, preferably 1.0 or less. For the contact method between the plating film 12 and the treatment solution, an immersion method or a spray method can be applied. In this embodiment, the immersion method is used. The concentration of the acid component in the treatment solution is, for example, 0.1% by mass or more and 10% by mass or less. The treatment conditions in the recess formation 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.
[0044] When the particle 16 is an organic compound particle, the treatment liquid used in the recess formation step may be a solution containing an acid component of either an organic acid or an inorganic acid, or an organic solvent. Examples of the organic solvent include lower alcohols such as acetone, methyl ethyl ketone, cellosolve, toluene, xylene, and methanol, and ethyl acetate. As the method of contacting the plating film 12 with the treatment liquid, the dipping method, the spraying method, or exposure in saturated vapor can be applied. Further, in the case of the dipping method for example, the treatment conditions in the recess formation step are such that the contact time is 1 hour or more and 24 hours or less, and the temperature is 10°C or more and below the boiling point of the organic solvent used.
[0045] As shown in FIG. 4, in the etching step, an etching layer 15 including at least one of an oxide of a metal component and a hydroxide of the metal component, and having a groove portion 15G is formed on the surface of the film portion 13 constituting the surface of the plating film 12. In the etching step, chemical etching is performed on the surface of the deposited metal 14 by bringing an etching liquid into contact with the surface of the deposited metal 14 constituting the film portion 13. Thereby, an etching layer 15 having a groove portion 15G is formed on the surface of the film portion 13. The flat portion 12A and the recess portion 12B on the surface of the plating film 12 are constituted by the etching layer 15.
[0046] As the etching liquid, it is preferable to select a liquid suitable for chemical etching of the metal component contained in the film portion 13, such as an inorganic acid, an inorganic alkali, an organic acid, an organic alkali, etc. For example, when the metal component contained in the film portion 13 is nickel, an etching liquid containing as a main component one or more acids selected from the group consisting of phosphoric acid, hydrochloric acid, sulfuric acid, nitric acid, and hydrofluoric acid may be used. Alternatively, an etching liquid containing as a main component one or more alkalis selected from the group consisting of potassium hydroxide, ammonia, and amine may be used.
[0047] The second member 20 is joined to the first member 10 provided with the plating film 12 manufactured by the above procedure. That is, the manufacturing method of the joined body 1 is to manufacture the first member 10 having the plating film 12 formed on the surface or on the surface of the plating target material 11 using the manufacturing method of the plating film 12 described above, and then join the second member 20 to the plating film 12 of the first member 10.
[0048] The manufacturing method of the joined body 1 may be any method as long as the surface shape of the etching layer 15 provided in the first member 10 is not damaged and a part of the second member 20 enters into the concave portion 12B, groove portion 15G, etc. that the etching layer 15 has.
[0049] For example, the second member 20 may be joined by solidifying an arbitrary material such as a molten polymer material or metal material in a state of being in contact with the etching layer 15. Specific examples of the joining method of the second member 20 may be insert molding, adhesion with an adhesive, brazing such as brazing or soldering. Alternatively, after melting a part of the second member 20 made of a polymer material, the part may be solidified in a state of being in contact with the etching layer 15. Or, if the surface shape of the etching layer 15 is not damaged, the joining method of the second member 20 may be a solid-phase joining such as ultrasonic joining or forging.
[0050] Note that, for the manufacturing method of the plating film 12, a first manufacturing method in which an etching process is performed after the concave portion forming process may be adopted, or a second manufacturing method in which the concave portion forming process and the etching process are performed simultaneously may be adopted.
[0051] In the first manufacturing method, after forming the concave portion 12B on the surface of the plating film 12 using a treatment liquid in which the particles 16 are soluble, an etching layer 15 having a groove portion 15G is formed on the surface of the film portion 13 using an etching liquid different from the treatment liquid. In this case, for the treatment liquid in the concave portion forming process, a solution in which the film portion 13 is insoluble or hardly soluble may be used. Note that the film portion 13 being hardly soluble refers to a solubility such that the etching layer 15 having the groove portion 15G is not sufficiently formed on the surface of the film portion 13 in the concave portion forming process.
[0052] In the second manufacturing method, after the plating film forming process, while forming the concave portion 12B on the surface of the plating film 12 using a treatment liquid in which the particles 16 are soluble and the film portion 13 can be chemically etched, an etching layer 15 having a groove portion 15G is formed on the surface of the film portion 13. That is, in the second manufacturing method, the treatment liquid for dissolving the particles 16 also serves as the etching liquid for forming the etching layer 15 on the surface of the film portion 13.
[0053] [Plating Solution for Electroless Plating] The plating solution used in the electroless plating method contains particles 16, metal components, a reducing agent, a complexing agent, and a pH adjusting agent. The amount of particles 16 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. The particles 16 do not dissolve in the plating solution but exist dispersed in the plating solution.
[0054] In electroless plating, the metal component can be any of the various metals mentioned above. As an example, a water-soluble nickel compound that is soluble in the plating solution can be used as the metal component. 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. Nickel sulfate is particularly preferred because of its good solubility in the plating solution. The concentration of the water-soluble nickel compound is, for example, 0.5 g / L or more and 50 g / L or less.
[0055] The reducing agent is, for example, at least one selected from the group consisting of hypophosphorous acid, hypophosphate (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.
[0056] The complexing agent is, for example, at least one selected from the group consisting of monocarboxylic acids, dicarboxylic acids, hydroxycarboxylic acids, aminopolycarboxylic acids, ethylenediaminediacetic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, and their ammonium, potassium, and sodium salts. Examples of monocarboxylic acids are acetic acid or formic acid. Examples of dicarboxylic acids are malonic acid, succinic acid, adipic acid, maleic acid, and fumaric acid. Examples of hydroxycarboxylic acids are malic acid, lactic acid, glycolic acid, gluconic acid, and citric acid. Examples of aminopolycarboxylic acids are ethylenediaminetetraacetic acid and diethylenetriaminepentaacetic acid. Other complexing agents such as phosphonic acids and amino acids may also be used. The concentration of the complexing agent is, for example, 5 g / L or more and 180 g / L or less.
[0057] The pH adjusting agent is, for example, at least one selected from the group consisting of inorganic acids such as sulfuric acid and phosphoric acid, sodium hydroxide, and ammonia water. The pH range of the plating solution in electroless plating is usually between 2 and 9. In this embodiment, however, the pH range of the plating solution in electroless plating is between 4.0 and 6.0.
[0058] Furthermore, various additives may be added to the plating solution. One example of an additive is a stabilizer, which is at least one selected from the group consisting of 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. The amount of stabilizer added is, for example, 0.01 mg / L to 100 mg / L. Another example of an additive is a pH buffer, which is at least one selected from the group consisting of boric acid, phosphoric acid, phosphorous acid, carbonic acid, and their sodium, potassium, and ammonium salts. The amount of buffer added is, for example, 0.1 g / L to 200 g / L. Another example of an additive is a surfactant, which can be used individually or in combination of two or more nonionic, cationic, anionic, or amphoteric surfactants. The amount of surfactant added is, for example, 0.1 mg / L to 100 mg / L.
[0059] In the first manufacturing method, which involves an etching step after a recess formation step, an example of a plating solution in the electroless plating method includes 25 g / L nickel sulfate hexahydrate, 25 g / L sodium hypophosphite monohydrate, 20 g / L malic acid, 10 g / L sodium acetate, 10 g / L sodium hydroxide, and 10 g / L manganese phosphate. In addition, any stabilizer may be added to the plating solution so that the bismuth ion concentration in the plating solution is 0.5 mg / L.
[0060] Furthermore, in the first manufacturing method using the electroless plating method with the above-mentioned plating solution, the processing solution used in the recess formation step is a solution in which the nickel component contained in the film portion 13 is insoluble or sparingly soluble, and one example is an organic acid such as citric acid. In this case, the etching solution used in the etching step is nitric acid, a nitro compound, or a mixture of hydrochloric acid and iron(II) chloride.
[0061] In the second manufacturing method, which performs the recess formation step and the etching step simultaneously, the same plating solution as in the first manufacturing method can be used for the electroless plating method. Furthermore, in the second manufacturing method using the electroless plating method with the above-mentioned plating solution, the treatment solution in which the particles 16 are soluble and which can chemically etch the film portion 13 is nitric acid, or a mixture of hydrochloric acid and iron(II) chloride.
[0062] [Electroplating] The plating solution used in the electroplating method contains metal components in addition to the particles 16. The amount of particles 16 added can be within the same numerical range as in the electroless plating method, even in the electroplating method. Note that the particles 16 are not dissolved in the plating solution but exist dispersed in the plating solution.
[0063] In electroplating, the metal component can be any of the various metals mentioned above. As an example, a water-soluble nickel compound that is soluble in the plating solution can be used as the metal component. In this case, a Watt bath or a nickel sulfamate bath can be used as the plating solution.
[0064] In the case of a Watt bath, the metal 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 preferred in terms of its excellent deposition properties on the material to be plated 11, and a mixture of nickel sulfate hexahydrate and nickel chloride hexahydrate is more preferred. When nickel sulfate hexahydrate and nickel chloride hexahydrate are used as a mixture as the metal component, it is preferable that the amount of nickel sulfate hexahydrate added is 200 g / L or more and 500 g / L or less, and the amount of nickel chloride hexahydrate added is 70 g / L or less. In the case of a nickel sulfamate bath, the metal component is, for example, water-soluble nickel compounds such as nickel sulfamate, nickel chloride hexahydrate, or a mixture thereof.
[0065] Furthermore, various primary 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, derivatives such as benzene and naphthalene (such as sodium naphthalene sulfonate), sulfonates, and sulfonamides. The secondary brightener is at least one selected from the group consisting of butinediol, propargyl alcohol, and coumarin.
[0066] In the first manufacturing method, an etching step is performed after the recess formation step, and in the second manufacturing method, the recess formation step and the etching step are performed simultaneously. In the case of a Watt bath, an example of the plating solution includes 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 nickel oxalate dihydrate particles. In addition, it may also contain 2 g / L or less of saccharin and 0.2 g / L or less of butinediol as brighteners. Furthermore, the pH range of the plating solution is 4.0 or more and 4.5 or less.
[0067] In the first manufacturing method, in which an etching step is performed after a recess formation step, and in the second manufacturing method, in which the recess formation step and the etching step are performed simultaneously, an example of a plating solution in the case of a nickel sulfamate bath contains 450 g / L of nickel sulfamate tetrahydrate, 15 g / L of nickel chloride hexahydrate, 30 g / L of boric acid, and 5 g / L of nickel oxalate dihydrate particles. The pH range of the plating solution is 4.0 to 4.5.
[0068] Furthermore, in the first manufacturing method using the electroplating method with the above-mentioned plating solution, the processing solution used in the recess formation step is a solution in which the nickel component contained in the film portion 13 is insoluble or sparingly soluble, and one example is an organic acid such as citric acid. In this case, the etching solution used in the etching step is nitric acid, a nitro compound, or a mixture of hydrochloric acid and iron(II) chloride. Furthermore, in the second manufacturing method using the electroplating method with the above-mentioned plating solution, the processing solution in which the particles 16 are soluble and which can chemically etch the film portion 13 is nitric acid, or a mixture of hydrochloric acid and iron(II) chloride.
[0069] [Effects of the Embodiment] (1) Because the surface of the coating portion 13 has recesses 12B, the surface area of the coating portion 13 is increased compared to a configuration in which the surface of the coating portion 13 does not have recesses 12B. Furthermore, by providing an etching layer 15 having grooves 15G on the surface of the coating portion 13 whose surface area has been increased by the recesses 12B, the bonding strength can be increased by the anchoring effect.
[0070] (2) Since the surface of the coating portion 13 has a smooth portion 12A, the load can be distributed over a larger area compared to a configuration in which the surface of the plating film 12 does not have a smooth portion 12A, thereby suppressing deterioration of the surface shape of the plating film 12.
[0071] (3) The etching layer 15, in a cross-sectional view taken from a viewpoint opposite to the plane including the thickness direction of the plating film 12, contains 50 to 200 grooves 15G per 100 μm in a one-dimensional direction along the surface of the plating film 12. With the above configuration, the bonding strength can be suitably improved by the anchoring effect.
[0072] (4) An example of a method for manufacturing the plating film 12 is a first manufacturing method in which an etching step is performed after the recess formation step. In this case, the etching step is performed using an etching solution different from the solution used in the recess formation step. With a manufacturing method in which the recess formation step and the etching step are performed separately, even if the metal component of the film portion 13 (i.e., the deposited metal 14) is not easily etched by the solution used to dissolve the particles 16, an etched layer 15 having grooves 15G can be suitably formed.
[0073] (5) An example of a method for manufacturing the plating film 12 is a second manufacturing method in which the recess formation step and the etching step are performed simultaneously. In this case, a treatment solution is used in which the particles 16 are soluble and the film portion 13 can be chemically etched, as the solution for dissolving the particles 16 and forming the etching layer 15. According to the above manufacturing method, the manufacturing process for the plating film 12 can be simplified.
[0074] (6) The second member 20 is preferably joined by solidifying the molten material in contact with the plating film 12. According to the above manufacturing method, the material constituting the second member 20 enters into the recesses 12B and grooves 15G on the surface of the coating portion 13, thereby suitably increasing the bonding strength between the first member 10 having the plating film 12 and the second member 20.
[0075] [Examples of Modifications] This embodiment can be implemented with the following modifications. This embodiment and the following examples of modifications can be combined with each other to the extent that they do not contradict each other technically.
[0076] - If sufficient bonding strength can be obtained in the joint 1, the number of grooves 15G in cross-sectional view may be less than 50 per 100 μm or more than 200 in the one-dimensional direction along the surface of the plating film 12.
[0077] Various undercoat plating films may be provided between the material to be plated 11 and the plating film 12. For example, if a sufficiently thick plating thickness is required relative to the particle size of the particles 16, an undercoat plating film of the same type as the deposited metal 14 may be provided between the material to be plated 11 and the plating film 12 using a plating solution that does not contain particles 16. In this case, the undercoat plating film that does not contain particles 16 can prevent the recesses 12B from reaching the material to be plated 11. The undercoat plating film provided between the material to be plated 11 and the plating film 12 does not have to be a plating film of the same type as the deposited metal 14.
[0078] [Examples] Examples 1 to 3 and Comparative Examples 1 to 5 will be described below with reference to Figures 5 to 9. Note that each example and each comparative example is not limited to the embodiments described above.
[0079] [Configuration of Joint 1] As shown in Figures 5 and 6, in Examples 1 to 3 and Comparative Examples 1 to 5, a joint 1 was fabricated by joining a second member 20 to a first member 10. For the first member 10, a cold-rolled steel plate (SPCC: Steel Plate Cold Commercial) with a length L1 of 45 mm, a width W1 of 18 mm, and a thickness T1 of 1.6 mm was used as the material to be plated 11.
[0080] First, plating treatment was performed at each level of Examples 1 to 3 and Comparative Examples 1 to 5 under the conditions described later. As a surface treatment prior to the plating treatment, the surface of the cold-rolled steel sheet was cleaned in the following order: alkaline degreasing, deionization water washing, PR (Periodic Reverse) electrolytic degreasing, deionization water washing, pickling (10% hydrochloric acid), and deionization water washing.
[0081] Subsequently, at each level, the second member 20 was joined to the first member 10 by injection molding (insert molding). The material used for the second member 20 was polybutylene terephthalate containing 40% by mass of glass fiber. The shape of the joined body 1 was the shape of a tensile shear test specimen in accordance with ISO 19095. Specifically, the shape of the second member 20 was a length L2 of 45 mm, a width W2 of 10 mm, and a thickness T2 of 3.0 mm. In addition, the joined body 1 was configured so that the widthwise centers of the first member 10 and the second member 20 coincided with each other.
[0082] In the joint 1, the length L3 of the joint between the first member 10 and the second member 20 was set to 5 mm. That is, the area of the joint between the first member 10 and the second member 20 was set to 5 mm (length L3) × 10 mm (width W2). In Figure 5, the joint between the first member 10 and the second member 20 is indicated by dots.
[0083] A fully automatic small injection molding machine (manufactured by Sumitomo Heavy Industries, Ltd., product series name: SE100EV) was used to mold the second member 20. The molding conditions were a resin temperature of 290°C, a mold temperature of 120°C, an injection pressure of 200 MPa, and an injection speed of 20 mm / s. The injection gate G1 (see Figure 6) was positioned directly above the surface of the plating film 12 formed on the first member 10.
[0084] The following describes the plating conditions for each level of Examples 1 to 3 and Comparative Examples 1 to 5. [Example 1] The substrate was immersed in an electroless plating solution stirred with a stirrer and air bubbling, and electroless plating was performed at 90°C until the film thickness reached approximately 5 μm. The plating solution used was a medium-to-high phosphorus type electroless nickel plating solution "SE-666" (manufactured by Nippon Kanigen Co., Ltd.), to which 2 g / L of manganese phosphate particles "PL-VMA" (manufactured by Nippon Parkerizing Co., Ltd.) and 20 mg / L to 30 mg / L of thiodiglycolic acid were added. During the plating process, the substrate 11 was held so that the angle of the surface of the substrate 11 with respect to the surface of the plating solution was between 45 degrees and 60 degrees. The "PL-VMA" used was classified so that the particle size range was between 0.2 μm and 6.0 μm, and the median diameter D50 was 0.6 μm.
[0085] Next, the manganese phosphate particles co-deposited on the surface of the plated film were dissolved and removed by immersion in 15% hydrochloric acid at room temperature (for example, 20°C to 25°C) for 30 seconds, followed by washing with water and drying. Then, the film was immersed in an etching solution containing 100 mL / L of 35% hydrochloric acid and 50 g / L of iron(III) chloride at room temperature for 1 minute. Following these steps, a plated film 12 having an etching layer 15 was formed on the first member 10.
[0086] [Example 2] Except that PL-VMA was used which had been classified so that the particle size range was 1.5 μm or more and the median diameter D50 was 4.1 μm, a plated film 12 having an etching layer 15 was formed on the first member 10 using the same procedure as in Example 1.
[0087] [Example 3] Except that PL-VMA was used which had been classified so that the particle size range was 2.0 μm or more and the median diameter D50 was 11.0 μm, a plating film 12 having an etching layer 15 was formed on the first member 10 using the same procedure as in Example 1.
[0088] [Comparative Example 1] Except that "PL-VMA" was not added to the plating solution, a plated film 12 having an etching layer 15 was formed on the first member 10 using the same procedure as in Example 1.
[0089] [Comparative Example 2] Except for omitting the etching process using an etching solution, a plating film 12 without an etching layer 15 was formed on the first member 10 using the same procedure as in Example 1.
[0090] [Comparative Example 3] Except for omitting the etching process using an etching solution, a plating film 12 without an etching layer 15 was formed on the first member 10 using the same procedure as in Example 2.
[0091] [Comparative Example 4] Except for omitting the etching process using an etching solution, a plating film 12 without an etching layer 15 was formed on the first member 10 using the same procedure as in Example 3.
[0092] [Comparative Example 5] Except that "PL-VMA" was not added to the plating solution and the etching process using the etching solution was omitted, a plating film 12 without an etching layer 15 was formed on the first member 10 using the same procedure as in Example 1.
[0093] [Method for evaluating the ratio of recessed areas] For Examples 1 to 3 and Comparative Examples 2 to 4, the ratio of recessed areas 12B on the surface of the plated film 12 was measured by observing SEM images (backscattered electron images) acquired from the plated film 12 using a scanning electron microscope (SEM).
[0094] [Method for evaluating the number of recesses and the opening width of recesses] For Examples 1 to 3 and Comparative Examples 2 to 4, copper plating was electroplated onto the plated film 12 for surface protection, and then the film was embedded in resin. The cross-section of the plated film 12, including the thickness direction, was then processed to allow observation. The number of recesses 12B having a depth of 1 μm or more per unit length of 100 μm and the sum of the opening widths were measured by observing the SEM image (backscattered electron image) of the cross-section.
[0095] [Method for Evaluating the Number of Grooves] For Examples 1 to 3 and Comparative Examples 1 to 4, after resin embedding, the cross-section including the thickness direction of the plated film 12 was processed to allow observation. Then, by observing the SEM image (backscattered electron image) of the cross-section, the number of grooves 15G that reached the deposited metal 14 from the surface of the etching layer 15 was measured per unit length of 100 μm. Here, the number of grooves 15G per 100 μm was calculated by multiplying the number of grooves 15G per 20 μm measured in a 6000x field of view by 5. Then, the above operation was performed on three cross-sections and the average value was calculated.
[0096] [Method for evaluating joint strength] For Examples 1 to 3 and Comparative Examples 1 to 5, tensile shear tests were performed using a universal material testing machine (Instron, model: 5583) at a crosshead speed of 3 mm / min to measure the fracture stress of the joint 1.
[0097] [Evaluation Results] Figure 7 shows the evaluation results for each of the above evaluations for Examples 1 to 3 and Comparative Examples 1 to 5.
[0098] As shown in Figure 7, in Examples 1 to 3 and Comparative Examples 2 to 4, in which recesses 12B were provided in the plating film 12, the area ratio of the recesses 12B was 5% to 40%. In addition, in Examples 1 to 3 and Comparative Examples 2 to 4, in the cross-section of the plating film 12, the number of recesses 12B per 100 μm was 10 to 50, and the sum of the opening widths of the recesses 12B per 100 μm was 5 μm to 30 μm.
[0099] In Examples 1 to 3, where the plated film 12 was provided with recesses 12B and an etching layer 15, the average number of grooves 15G per 100 μm in the cross-section of the plated film 12 was between 82 and 138. In Comparative Example 1, where the plated film 12 was provided with an etching layer 15 but without recesses 12B, the number of grooves 15G per 100 μm in the cross-section of the plated film 12 was 13.
[0100] Figure 8 shows a cross-section of Example 3 as observed at a 6000x magnification field of view. As shown in Figure 8, the plating film 12 of Example 3 comprises a deposited metal 14 and an etching layer 15. The surface of the etching layer 15 is a surface that constitutes the surface of the plating film 12, which has a smooth portion 12A and a recessed portion 12B. Grooves 15G are formed in the etching layer 15 in the thickness direction when viewed in cross-section. In this cross-section, 30 grooves 15G were observed per 20 μm. Note that in Figure 8 and Figure 9 described later, the positions of the grooves 15G that reach the deposited metal 14 from the surface of the etching layer 15 are indicated by arrows.
[0101] Figure 9 shows a cross-section of Comparative Example 1 as observed at a 6000x magnification field of view. As shown in Figure 9, the plating film 12 of Comparative Example 1 comprises a deposited metal 14 and an etching layer 15. The plating film 12 of Comparative Example 1 does not have recesses 12B. In a cross-sectional view, grooves 15G are formed in the etching layer 15, recessed in the thickness direction. In this cross-section, three grooves 15G were observed per 20 μm.
[0102] Returning to Figure 7, in Examples 1 to 3, where the plated film 12 was provided with recesses 12B and an etching layer 15, the breaking stress was 17.8 MPa to 20.7 MPa. In contrast, in Comparative Example 1, where the plated film 12 was provided with an etching layer 15 but without recesses 12B, the breaking stress was 7.1 MPa. In Comparative Examples 2 to 4, where the plated film 12 was provided with recesses 12B but without an etching layer 15, the breaking stress was 1.9 MPa to 3.3 MPa. In Comparative Example 5, where neither recesses 12B nor an etching layer 15 was provided on the plated film 12, fracture occurred immediately after the start of the test (0 MPa). From the above, it was confirmed that providing both recesses 12B and an etching layer 15 with grooves 15G on the plated film 12 significantly increased the bonding strength compared to providing them individually.
Claims
1. A method for manufacturing a plating film to be provided on or on the surface of a material to be plated to be joined to another member, comprising: using a plating solution in which a metal component is dissolved and particles are dispersed, depositing a film portion derived from the metal component onto or on the surface of the material to be plated by an electroless plating method or an electroplating method, thereby forming a plating film in which the particles are co-deposited inside and on the surface of the film portion; contacting the plating film with a solution to dissolve the particles present on the surface of the plating film in the solution and form recesses on the surface of the plating film; and forming an etching layer on the surface of the film portion that contains at least one of the oxide of the metal component and the hydroxide of the metal component and has grooves that are recessed in the thickness direction.
2. The method for manufacturing a plated film according to claim 1, wherein forming the etching layer includes forming the etching layer such that, in a cross-sectional view taken from a viewpoint opposite to the plane including the thickness direction of the plated film, the etching layer includes 50 to 200 grooves per 100 μm in a one-dimensional direction along the surface of the plated film.
3. The method for manufacturing a plated film according to claim 1, wherein the etching layer is formed by the solution.
4. The method for manufacturing a plated film according to claim 1, wherein forming the etching layer includes forming the etching layer on the surface of the plated film including the recess using an etching solution different from the solution.
5. A method for manufacturing a joined body, comprising: manufacturing a first member having a plating film formed on or on the surface of a material to be plated using a method for manufacturing a plating film according to any one of claims 1 to 4; and, after manufacturing the first member, joining a second member to the plating film of the first member.
6. The method for manufacturing a joined body according to claim 5, wherein joining the second member includes joining the second member to the plating film of the first member by solidifying a molten material in contact with the plating film.
7. A plating film provided on or on the surface of a material to be plated to be joined to another member, comprising a film portion derived from a metal component and particles located inside the film portion, wherein the film portion has an etching layer on its surface containing at least one of the oxide of the metal component and the hydroxide of the metal component, the surface of the etching layer comprises a smooth portion that follows the surface of the material to be plated and a recess having a shape that conforms to at least a part of the outer shape of the particles, and the etching layer is a plating film having grooves recessed in the thickness direction.
8. The plated film according to claim 7, wherein the etching layer, in a cross-sectional view taken from a viewpoint opposite to the plane including the thickness direction of the plated film, includes 50 to 200 grooves per 100 μm in a one-dimensional direction along the surface of the plated film.
9. A joint comprising: a first member having a material to be plated and a plating film according to claim 7 or 8; and a second member joined to the plating film.