Manufacturing method for plated products

Abstract

A base material 1 is a non-electroconductive member and is made of, e.g., a carbon composite material or a resin such as engineering plastic or super engineering plastic. First, an electroless plating layer 3 made of, e.g., Ni is formed on the surface of the base material 1. Next, an aluminum plating layer 5 is formed on the surface of the electroless plating layer 3 by electrolytic plating. An adhesion-improving layer 9 made of, e.g., Cu may be formed between the electroless plating layer 3 and the aluminum plating layer 5.

Description

[Technical Field]

[0001] This invention relates to plated products having a plating applied to the surface of a substrate, and to a method for manufacturing the same. [Background technology]

[0002] Carbon fiber composite materials, for example, are used as lightweight and high-strength materials. Carbon fiber composite materials are made by impregnating carbon fiber sheets with resin and hardening them, and because they are lightweight and high-strength, they are used in a variety of fields. However, carbon fiber composite materials are generally black with a pattern of carbon fiber weave, so they are not necessarily aesthetically pleasing.

[0003] To enhance the aesthetic appeal of components made from resins and the like, methods have been proposed to paint the resin surface, as well as to form a plating layer capable of producing a metallic luster (for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2023-16073 [Overview of the project] [Problems that the invention aims to solve]

[0005] Such plating layers are generally created by applying electroless plating to the surface of a resin, or by applying electrolytic chromium plating to that surface. Both methods produce a metallic appearance. However, they do not provide a high-quality texture and do not necessarily offer sufficient aesthetic appeal.

[0006] This invention has been made in view of the above problems, and aims to provide plated products and the like that can achieve high design quality. [Means for solving the problem]

[0013] In order to achieve the above object, the present invention provides a method for manufacturing a plated product, comprising: forming an electroless Ni plating layer on a non-conductive substrate; forming a Cu plating layer on the surface of the Ni plating layer; laminating an aluminum plating layer by electrolytic plating on the surface of the Cu plating layer; and the electrolytic solution used when laminating the aluminum plating layer contains at least one nitrogen-containing compound selected from the group consisting of dialkyl sulfone, aluminum halide, and ammonium halide, hydrogen halide salt of primary amine, hydrogen halide salt of secondary amine, hydrogen halide salt of tertiary amine, and quaternary ammonium salt represented by the general formula: R R R R 1 R 2 R 3 R 4 N·X (where R 1 ~R 4 are the same or different alkyl groups, and X represents a counter anion for a quaternary ammonium cation); between the step of forming the Cu plating layer on the surface of the Ni plating layer and the step of forming the aluminum plating layer, after immersing the member on which the Cu plating layer is formed in the non-aqueous electrolytic solution, the member on which the Cu plating layer is formed is vibrated for 3 seconds or more Ruko A method for manufacturing a plated product, characterized by the above.

[0014] Furthermore, it may further include a step of performing an anodic oxidation treatment on the surface of the aluminum plating layer.

[0015] The aforementioned base material is preferably a fiber-reinforced plastic. In the process of forming the aluminum plating layer, it is desirable to use the member on which the Cu plating layer is formed as the cathode and aluminum as the material of the anode.

Advantages of the Invention

[0018] According to the present invention, it is possible to provide a plated product or the like that can obtain high design quality. [Brief explanation of the drawing]

[0019] [Figure 1A] A conceptual diagram showing the manufacturing process for plated products 10 and 10a. [Figure 1B] A conceptual diagram showing the manufacturing process for plated products 10 and 10a. [Figure 1C] A conceptual diagram showing the manufacturing process for plated products 10 and 10a. [Figure 1D] A conceptual diagram showing the manufacturing process of plated product 10a. [Figure 2] A conceptual diagram showing plated product 10b. [Figure 3A] Photograph of the electrodeposited film on the surface of the cathode electrode (current density 10-80 mA / cm²) [Figure 3B] Electrodeposition film photograph of the cathode electrode cross-section (current density 10-80 mA / cm²) [Figure 4A] Photograph of the electrodeposited film on the surface of the cathode electrode (current density 10 mA / cm²) [Figure 4B] Photograph of the electrodeposited film in the cross-section of the cathode electrode (current density 10 mA / cm²) [Modes for carrying out the invention]

[0020] A plated product in an embodiment of the present invention is characterized by comprising a non-conductive substrate, an electroless plating layer formed on the surface of the substrate, and an aluminum plating layer laminated on the electroless plating layer. Furthermore, by providing an anodic oxide film formed on the surface of the aluminum plating layer, it is possible to achieve a higher degree of design freedom. In this case, it is desirable that the thickness of the aluminum plating layer, including the thickness of the anodic oxide film, is 20 μm to 100 μm (20 μm or more and 100 μm or less; the same applies hereinafter). Preferably, the electroless plating layer is a nickel (Ni) plating layer, and a copper (Cu) plating layer is present between the Ni plating layer and the aluminum plating layer. In particular, it is preferable that the Cu plating layer and the Ni plating layer, or the Cu plating layer and the aluminum plating layer, are formed to be adjacent to each other and in close contact. The Ni plating layer is harder than the Cu plating layer and the aluminum plating layer, and it is desirable that the Cu plating layer is harder than the aluminum plating layer. It is desirable that the Ni plating layer is 0.1 μm to 5 μm, and the Cu plating layer is 1 to 30 μm. Alternatively, the Ni plating layer may be 0.1 μm to 1 μm, the Cu plating layer may be 1 μm to 30 μm, and the Ni plating layer may be thinner than the Cu plating layer. It is desirable that the base material is a fiber-reinforced plastic.

[0021] Moreover, a method for manufacturing a plated product in an embodiment for carrying out the present invention includes a step of forming an electroless plating layer on a non-conductive base material, and a step of laminating an aluminum plating layer on the electroless plating layer by electrolytic plating. More preferably, it is preferable to include a step of performing an anodic oxidation treatment on the surface of the aluminum plating layer. The electrolytic solution when forming the aluminum plating layer is dialkyl sulfone, aluminum halide, and at least one nitrogen-containing compound selected from the group consisting of ammonium halide, hydrogen halide salt of primary amine, hydrogen halide salt of secondary amine, hydrogen halide salt of tertiary amine, general formula: R 1 R 2 R 3 R 4 N·X (R 1 ~R 4 represents the same or different alkyl groups, and X represents a counter anion for a quaternary ammonium cation) and is desirably at least one nitrogen-containing compound selected from the group consisting of quaternary ammonium salts. An oxide film removal step of removing the oxide film of the Ni plating layer may be provided between the step of forming the Ni plating layer and the step of forming the Cu plating layer. In the step of forming the aluminum plating layer, after immersing the member on which the Cu plating layer is formed in the non-aqueous electrolytic solution, electrolysis may be energized after a holding time of 3 seconds or more.

[0022] Embodiments of the present invention will be described below with reference to the drawings. Figures 1A to 1D are conceptual diagrams showing the manufacturing process of plated products 10, etc., according to the present invention. In Figure 1A, the base material 1 is a non-conductive material and includes resin or inorganic materials such as glass or ceramics. In particular, among the non-conductive materials, if it is a non-conductive resin material, for example, polyethylene terephthalate, carbon fiber or glass fiber reinforced plastics (CFRP (Carbon Fiber Reinforced Plastics) or GFRP (Glass Fiber Reinforced Plastics)). Examples include fiber-reinforced plastics, engineering plastics such as polycarbonate, polyimide, and polyphenylene sulfide, or super engineering plastics. While the example shown illustrates the substrate 1 as a plate, it can take any shape, such as electronic equipment casings, mobility components, or outdoor / leisure goods. Furthermore, if the substrate 1 is a non-conductive resin material with flexibility, it can be applied to deformable objects, allowing for a wide range of applications. On the other hand, when applied to ceramics as an inorganic material, it can, for example, impart a metallic texture to pottery.

[0023] Next, as shown in Figure 1B, an electroless plating layer 3 is formed on the surface of the substrate 1. The electroless plating layer 3 is not particularly limited, but from the viewpoint of adhesion to the substrate 1 and manufacturability, it is desirable to include one or more of the following: Cu, Ni, Au (gold), Pd (palladium), Sn (tin), Ag (silver), and Pt (platinum). The electroless plating layer 3 can be formed by known methods. The thickness of the electroless plating layer 3 can be, for example, about 0.1 μm to 5 μm. In addition, before electroless plating, the surface of the substrate 1 may be roughened by polishing, grinding, blasting, etching, etc. By doing so, the adhesion between the substrate 1 and the electroless plating layer 3 can be improved.

[0024] Next, as shown in Figure 1C, an aluminum plating layer 5 is laminated onto the electroless plating layer 3 by electroplating. At this time, it is desirable to remove the oxide film from the surface of the electroless plating layer 3 by pickling or other means as needed. The thickness of the aluminum plating layer 5 should preferably be at least 3 μm. In this way, the underlying electroless plating layer 3 can be completely covered so that it is not visible, and functions such as electrical conductivity and thermal conductivity can be imparted to the surface layer. Thus, the plated product 10 is manufactured.

[0025] The electrolyte used when laminating the aluminum plating layer 5 is not particularly limited, but for example, (1) dialkyl sulfone, (2) aluminum halide, and (3) ammonium halide, hydrogen halide of primary amine, hydrogen halide of secondary amine, hydrogen halide of tertiary amine, general formula: R 1 R 2 R 3 R 4 N·X(R 1 ~R 4 It is more preferable that the electrolyte contains at least one nitrogen-containing compound selected from the group consisting of quaternary ammonium salts (where is the same or different alkyl group and X represents a counteranion for the quaternary ammonium cation). Using this electrolyte, a high-purity aluminum plating layer 5 can be deposited on the electroless plating layer 3 at a fast film formation rate.

[0026] Examples of dialkyl sulfones to be included in the electrolyte include dimethyl sulfone, diethyl sulfone, dipropyl sulfone, dihexyl sulfone, and methyl ethyl sulfone, which have 1 to 6 carbon atoms in the alkyl group (they may be linear or branched). However, from the viewpoint of good electrical conductivity and ease of availability, dimethyl sulfone can be preferably used.

[0027] Examples of aluminum halides include aluminum chloride and aluminum bromide. It is preferable that the aluminum halide be in its anhydrous form.

[0028] Examples of ammonium halides that can be used as nitrogen-containing compounds include ammonium chloride and ammonium bromide. Furthermore, examples of primary to tertiary amines in the hydrogen halides of primary to tertiary amines include alkyl groups with 1 to 6 carbon atoms (either linear or branched), such as methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, propylamine, dipropylamine, tripropylamine, hexylamine, and methylethylamine. Examples of hydrogen halides include hydrogen chloride and hydrogen bromide. General formula: R 1 R 2 R 3 R 4 N·X(R 1 ~R 4 In quaternary ammonium salts, R is represented as (where is the same or different alkyl group, and X represents the counteranion for the quaternary ammonium cation). 1 ~R 4 Examples of alkyl groups represented by include methyl, ethyl, propyl, and hexyl groups, which have 1 to 6 carbon atoms (they can be linear or branched). X can be a halide ion such as chloride, bromide, or iodide, as well as BF4 - PF6 - Examples include the following. Specific examples of compounds include tetramethylammonium chloride, tetramethylammonium bromide, tetramethylammonium iodide, and tetraethylammonium boron tetrafluoride. As for suitable nitrogen-containing compounds, hydrochlorides of tertiary amines, such as trimethylamine hydrochloride, can be cited because they facilitate the formation of a high-purity aluminum plating layer 5 at a fast film formation rate.

[0029] The blending ratio of dialkylsulfone, aluminum halide, and nitrogen-containing compound is, for example, preferably 1.5 to 5.0 moles of aluminum halide, more preferably 2.0 to 4.2 moles, per 10 moles of dialkylsulfone. The blending ratio of nitrogen-containing compound is preferably 0.01 to 2.0 moles, more preferably 0.05 to 1.5 moles. If the amount of aluminum halide is less than 1.5 moles per 10 moles of dialkylsulfone, there is a risk that the formed aluminum plating layer 5 will darken (a phenomenon called burning) or the film formation efficiency will decrease. On the other hand, if the amount of aluminum halide exceeds 5.0 moles per 10 moles of dialkylsulfone, the electrolyte resistance will become too high, which may cause the electrolyte to generate heat and decompose. Furthermore, if the amount of nitrogen-containing compound is less than 0.01 moles per 10 moles of dialkylsulfone, the effects of blending, namely the effect of improving the film formation rate by realizing plating treatment with high current density based on improved electrical conductivity of the electrolyte, and the effects of high purity and improved ductility of the aluminum plating layer 5, may not be obtained. On the other hand, if the amount of nitrogen-containing compound exceeds 2.0 moles per 10 moles of dialkylsulfone, the composition of the electrolyte will change fundamentally, which may prevent aluminum from precipitation.

[0030] The plating process using the above-mentioned electrolyte can be performed, for example, with an electrolyte temperature of 80°C to 110°C and an applied current density of 0.5 mA / cm². 2 ~200mA / cm 2 Under these conditions, the process can be carried out by applying a voltage to the substrate 1 having the electroless plating layer 3 so that it is the cathode side (aluminum can be used as an example of the anode material). The lower limit of the electrolyte temperature should be determined considering the freezing point of the electrolyte, preferably 85°C, and more preferably 95°C (below the freezing point of the electrolyte, the plating solution will solidify, making plating impossible). On the other hand, setting the upper limit of the electrolyte temperature to 110°C can suppress deformation of the substrate 1. If the electrolyte temperature exceeds 110°C, the reaction between the aluminum plating layer 5 and the electrolyte becomes more active, and there is a risk that the purity of the aluminum plating layer 5 will decrease as many impurities are incorporated into it. Also, the applied current density is 0.5 mA / cm². 2 If the applied current density falls below this level, the film deposition efficiency may decrease. On the other hand, if the applied current density is 200 mA / cm², the film deposition efficiency may decrease. 2 If the concentration exceeds this level, stable plating may not be possible due to the decomposition of nitrogen-containing compounds, or a high-purity aluminum plating layer 5 may not be obtainable. The notable advantage of the above electrolyte is 100 mA / cm 2 The advantage is that stable plating is possible even when applying the above current densities, thus improving the film deposition rate. The plating time depends on the desired thickness of the aluminum plating layer 5, the temperature of the electrolyte, and the applied current density, but is usually 1 to 90 minutes. Considering production efficiency, 1 to 60 minutes is desirable.

[0031] Next, if necessary, the surface of the aluminum plating layer 5 can be polished to smooth it out, thereby enhancing the metallic luster.

[0032] Furthermore, reducing the size of the crystal grains in the aluminum plating layer 5 can reduce the surface roughness of the aluminum plating layer 5 after plating. Therefore, by intentionally including impurities such as Cu and Si (silicon) in the plating components of the aluminum plating layer 5, the crystal grains can be refined, thereby reducing surface roughness. For example, by ionizing a certain amount of Cu, etc., in the electrolyte during plating, the purity of the aluminum plating layer 5 can be intentionally reduced, resulting in finer crystal grains. For example, an aluminum alloy containing Si: 0.1% to 24% by mass, Cu: 0.1% to 5% by mass, and Fe (iron): 0.15% to 1.8% by mass is used as the anode electrode for the aluminum plating layer. The anode electrode can be obtained, for example, by shaping used AC2A alloy (JIS H 5202) material into an electrode shape through casting or other means. Furthermore, the anode current density during plating is set to 40 mA / cm². 2 ~200mA / cm 2 This allows the electrodeposited film to contain Cu.

[0033] Furthermore, as shown in Figure 1D, the surface of the aluminum plating layer 5 may be subjected to anodizing treatment to form an anodic oxide film 7 on the surface of the aluminum plating layer 5. Thus, a plated product 10a having an anodic oxide film is manufactured. The anodizing treatment method is not particularly limited and can be carried out by known methods. The anodizing treatment conditions are appropriately set according to the desired thickness of the anodic oxide film 7 and the anodizing solution used. Additionally, if necessary, the aluminum plating layer 5 may be divided into multiple parts, and each part may be subjected to anodizing treatment under different conditions. Furthermore, during the anodizing treatment, the anodic oxide film 7 may be given color by natural color development, or by coloring (so-called color anodizing).

[0034] Furthermore, the total thickness of the aluminum plating layer 5 (including the thickness of the anodic oxide film 7) is preferably 20 μm to 100 μm. The anodic oxide film 7 is formed on the surface side of the aluminum plating layer 5 in a direction that increases in thickness, and is also formed in a way that erodes a portion of the original aluminum plating layer 5. In other words, when performing electroplating, the aluminum plating layer 5 is formed with a thickness that takes into account the change in thickness due to the anodic oxide film 7 formed during the anodic oxidation treatment.

[0035] Furthermore, to improve the adhesion between the substrate 1 and the electroless plating layer 3, an adhesion-enhancing layer may be formed between the aluminum plating layer 5 and the electroless plating layer 3. For example, as shown in the plated product 10b in Figure 2, an adhesion-enhancing layer 9 may be provided between the electroless plating layer 3 and the aluminum plating layer 5. If the electroless plating layer 3 is a Ni plating layer, a Cu electroplating layer may be formed as the adhesion-enhancing layer 9. This Cu plating layer can be formed using a well-known plating solution and plating method.

[0036] Here, the adhesion-improving layer 9 is a layer for improving the adhesion between, for example, the substrate 1 and the aluminum plating layer 5. When a Ni plating layer is formed as the electroless plating layer 3, the surface of the Ni plating layer oxidizes due to oxygen in the atmosphere. If such an oxide film is formed on the surface of the Ni plating layer and the aluminum plating layer 5 is formed directly on the surface of the Ni plating layer, adhesion may be impaired. For this reason, it is desirable to completely remove the oxide film of the Ni plating layer by pickling or the like before forming the aluminum plating layer 5 on the surface of the Ni plating layer. However, it is difficult to completely remove the oxide film of Ni.

[0037] On the other hand, as mentioned above, in order to improve the adhesion between the substrate 1 and the aluminum plating layer 5, forming a Cu plating layer between the aluminum plating layer 5 and the Ni plating layer makes it easier to remove the oxide film required before forming the aluminum plating layer. In other words, it is preferable to form a Cu plating layer between the Ni plating layer and the aluminum plating layer, on which an oxide film that is weaker than the oxide film formed on the Ni plating layer is formed.

[0038] Furthermore, when forming a Cu plating layer on the surface of a Ni plating layer, even if the oxide film of the Ni plating layer was not completely removed, peeling between Ni and Cu was almost nonexistent compared to peeling between Ni and aluminum. This is presumed to be because the adhesion between Ni and Cu is sufficiently high compared to the adhesion between aluminum and other layers. For this reason, when forming a Cu plating layer on the surface of a Ni plating layer, the removal of the oxide film of the Ni plating layer can be omitted, or only a simpler pickling process may be used compared to when forming an aluminum plating layer on the surface of a Ni plating layer.

[0039] On the other hand, when forming a Cu plating layer using an aqueous plating solution that uses water as the solvent, a moisture removal treatment (e.g., drying) is performed afterward to form an oxide film on the surface of the Cu plating layer. However, even in this case, compared to the oxide film of Ni, the oxide film of Cu is easier to remove by immersing the Cu in a non-aqueous aluminum plating solution, particularly a non-aqueous plating solution consisting of the dialkyl sulfone, aluminum halide, and nitrogen-containing compound mentioned above, thereby reducing its impact. This makes it possible to improve the adhesion between the aluminum plating layer and the substrate. Therefore, it is preferable to form the aluminum plating layer directly on the surface of the Cu plating layer. In particular, when the substrate is formed of flexible polyethylene terephthalate or polyimide, the plated product according to the embodiment of the present invention will be used in a state of bending deformation. Even in that case, because the aluminum plating layer 5 has good adhesion to the Cu plating layer, it is possible to reduce the occurrence of defects such as peeling.

[0040] In particular, the non-aqueous plating solution consisting of the dialkyl sulfone, aluminum halide, and nitrogen-containing compound mentioned above contains AlCl4 ― Al2Cl7 -This is thought to be because various halide aluminum ion species, such as those mentioned above, are present, and these halides decompose and remove the copper oxide film. In order to reliably remove the oxide film from the Cu plating layer before forming the aluminum plating layer, it is desirable to immerse the Cu-plated component in a non-aqueous electrolyte solution during the aluminum plating layer formation process, and then apply electrolysis after a holding time of 3 seconds or more. For example, generally, to shorten the cycle time, electricity is applied immediately after immersion, but by deliberately holding a time for oxide film removal after immersion and then starting the electrolytic plating of aluminum after the oxide film has been removed, the influence of the oxide film on the Cu plating layer can be suppressed. During the oxide film removal time, the component to be plated may be vibrated or the electrolyte solution may be stirred.

[0041] In this case, it is desirable that the Ni plating layer is 0.1 μm to 5 μm thick and the Cu plating layer is 1 μm to 30 μm thick. Furthermore, it is even more preferable that the Ni plating layer is 0.1 μm to 1 μm thick and the Cu plating layer is 1 μm to 30 μm thick, with the Ni plating layer being thinner than the Cu plating layer. If the Ni plating layer is less than 0.1 μm thick, untreated areas such as pinholes may occur. Also, if the Ni plating layer exceeds 1 μm, or even more so if it exceeds 5 μm, it will take a lot of time to form by electroless plating. Also, if the Cu plating layer is less than 1 μm thick, untreated areas such as pinholes may occur, and the underlying layer may be exposed. Also, if the Cu plating layer exceeds 30 μm, the processing time will be long, which may reduce productivity.

[0042] Furthermore, as mentioned above, the Cu plating layer only needs to be thin enough that when the oxide film is formed, the oxide film is removed by the electrolyte of the aluminum plating layer, and no untreated areas such as pinholes are generated at that time. Thus, the Cu plating layer may be thinner than the outermost aluminum plating layer as long as adhesion to the aluminum plating layer is ensured.

[0043] Furthermore, the hardness of an aluminum plating layer is generally lower than that of copper or nickel. Also, copper is generally less hard than nickel. Therefore, by forming a Ni plating layer, a Cu plating layer, and an aluminum plating layer in sequence on the substrate 1, the hardness of adjacent materials in each layer becomes similar. By making the hardness of adjacent layers similar in this way, even when each layer deforms in conjunction with the deformation of the substrate 1, delamination between layers becomes less likely, and a plated product with good flexibility can be obtained. In this case, it is preferable to use Vickers hardness (with a test force of 25g) as the measurement method for hardness as an indicator. According to this measurement method, the hardness of high-purity aluminum is in the range of 35Hv to 170Hv, the hardness of copper is in the range of 100Hv to 200Hv, and the hardness of nickel is in the range of 400Hv to 700Hv. Although there is some overlap in the hardness ranges of each layer, the hardness can be adjusted by controlling the film formation conditions. Therefore, it is preferable that the hardness of the aluminum plating layer formed on a non-conductive substrate is harder than that of the copper plating layer and softer than that of the electroless nickel plating layer. Furthermore, it is preferable to make the nickel plating layer, which is the hardest layer, the thinnest layer.

[0044] As described above, according to this embodiment, the surface of the non-conductive member can be given an appearance with excellent design. Furthermore, by forming an anodic oxide coating, it is possible to color or develop any color, such as white, black, red, or blue, and it is also possible to change the color depending on the part.

[0045] Furthermore, by using an electrolyte containing (1) a dialkyl sulfone, (2) an aluminum halide, and (3) a desired nitrogen-containing compound as the electrolyte for forming the aluminum plating layer 5, it is possible to perform aluminum plating at a relatively low temperature of 80°C to 110°C, thereby suppressing deformation of the substrate 1. Furthermore, the disclosures in this specification also include the disclosure of the invention in the following embodiments, in order to enable the acquisition of plated products and the like that can achieve high design quality on non-conductive substrates.

[0046] To achieve the aforementioned objectives, one aspect of the present invention is a plated product characterized by comprising a non-conductive substrate, an electroless plating layer formed on the surface of the substrate, and an aluminum plating layer laminated on the electroless plating layer.

[0047] According to the first invention, by forming an electroless plating layer on the surface of a non-conductive substrate, it becomes possible to form an aluminum plating layer by electroplating, thereby improving the aesthetic appeal.

[0048] Furthermore, if the electroless plating layer is a Ni plating layer, and a Cu plating layer is formed between the Ni plating layer and the aluminum plating layer, peeling between the aluminum plating layer and the electroless plating layer can be suppressed. To reliably obtain this effect, it is desirable that the Ni plating layer is 0.1 μm to 5 μm thick and the Cu plating layer is 1 to 30 μm thick. Moreover, it is even more desirable that the Ni plating layer is 0.1 μm to 1 μm thick and the Cu plating layer is 1 μm to 30 μm thick, with the Ni plating layer being thinner than the Cu plating layer.

[0049] In this case, by setting the thickness of the aluminum plating layer within an appropriate range, it is possible to achieve both high design quality and manufacturability.

[0050] Furthermore, if the base material is fiber-reinforced plastic, high strength can be ensured.

[0051] Another aspect of the present invention is a method for manufacturing a plated product, comprising the steps of: forming an electroless Ni plating layer on a non-conductive substrate; forming a Cu plating layer on the surface of the Ni plating layer; and laminating an aluminum plating layer on the surface of the Cu plating layer by electroplating.

[0052] Furthermore, according to another aspect of the present invention, by forming a Cu plating layer between the electroless Ni plating layer and the aluminum plating layer, peeling of the aluminum plating layer and the electroless plating layer can be suppressed. In addition, by forming an anodic oxide film on the surface of the aluminum plating layer, high aesthetic appeal can be obtained.

[0053] Furthermore, by using an electrolyte consisting of dialkyl sulfone, aluminum halide, and nitrogen-containing compounds, it is possible to perform operations at lower temperatures compared to cases where molten salt is used, and handling is also safe and easy.

[0054] Furthermore, by including an oxide film removal step between the process of forming the Ni plating layer and the process of forming the Cu plating layer, the peeling of the Ni plating layer and the Cu plating layer can be suppressed more reliably.

[0055] Furthermore, in the process of forming the aluminum plating layer, by immersing the member on which the Cu plating layer has been formed in a non-aqueous electrolyte and then applying electrolysis after a holding time of 3 seconds or more, the oxide film on the surface of the Cu plating layer can be removed by the electrolyte before plating. [Examples]

[0056] (Example 1) The aesthetic appearance of this embodiment was verified. A CFRP substrate measuring 10 cm × 10 cm × 0.3 cm was used. The plating area was 10 cm × 8 cm × 2 surfaces. Ni electroless plating and aluminum electroplating were performed on this substrate. Alternatively, a Ni electroless plating layer, a Cu electroplating layer, and aluminum electroplating were performed. The electrolyte for aluminum electroplating was a 2 L solution containing 10 mol of dimethyl sulfone, 3.8 mol of aluminum chloride, 0.2 mol of ammonium chloride, and 1 mol of tetramethylammonium chloride, with a current density of 40-50 mA / cm². 2The solution temperature was set to 95°C to 100°C. For the anodizing treatment, an anodic oxide film was formed by primary electrolysis with an electrolyte solution, and coloring was applied by secondary electrolysis. As a result of visual inspection, no surface defects such as pinholes were found, and it was confirmed that an aluminum plating layer with a metallic texture had been formed on the CFRP substrate. Visual inspection was performed both before and after anodizing, and in both cases, the aluminum plating layer was directly touched to check for peeling, but no surface defects such as pinholes or peeling were found in either case. It was confirmed that by performing anodizing treatment on the aluminum plating layer, it is possible to obtain a plated product with a design featuring four colors (white, black, red, and blue) on the CFRP substrate. On the other hand, in order to evaluate adhesion under harsh conditions, a "grid test" was performed as Example 2 described later.

[0057] (Example 2) The adhesion between the substrate and the aluminum plating layer was evaluated under more severe conditions than in Example 1 for plated products manufactured using the same substrate and manufacturing method as in Example 1. The results are shown in Table 1. Table 1 also shows the results of the visual observation and the peeling test during surface contact performed in Example 1. In Table 1, sample numbers where the item name "Thickness of Cu plating layer" is labeled "-" indicate that no Cu plating layer was formed, and the aluminum plating layer was placed on top of the Ni plating layer. Furthermore, items labeled "Good" for the item name "Condition of aluminum plating layer and anodic oxidation film" indicate that, after the formation of the aluminum plating layer and the anodic oxidation film, no pinholes were observed, and no peeling was observed when the surface was rubbed by hand.

[0058] [Table 1]

[0059] For Nos. 1 to 8, an aluminum plating layer was formed directly on the surface of the electroless plating layer, while for Nos. 9 to 10, a Cu electroplating layer was formed between the electroless plating layer and the aluminum plating layer as an adhesion-enhancing layer.

[0060] A "grid test" was performed on the obtained samples. A 5x5 grid was created using a cutter, and cellophane tape was applied and peeled off. Samples in which the film within 25 squares did not peel off at all were classified as "no peeling." As a result, samples No. 9 to 10, which have an adhesion-enhancing layer, showed no peeling between the substrate and the aluminum plating layer, ensuring high adhesion.

[0061] Next, to evaluate the relationship between the plating conditions and the structure of the plating film (layer), electrolysis was performed using an aluminum electrolytic bath, and the electrodeposited film on the cathode electrode surface was observed as the equivalent of the plating layer in electroplating. An AC2A alloy was used as the anode electrode, and the anode current density and cathode current density were set to 10 mA / cm². 2 ~80mA / cm 2 The value was varied (median:

[45] mA / cm²). 2 (As shown). Figure 3A is an SEM image of the surface of the electrodeposited film, and Figure 3B is an SEM image of the cross-section of the electrodeposited film. An AC2A alloy was used as the anode electrode, and the median current density was 40 mA / cm². 2 Based on the above, some particles that appear to be Cu (the whitish particulate areas in the photograph) were observed in the cross-section. This indicates that Cu ions are being reduced on the cathode electrode surface.

[0062] In contrast, an AC2A alloy was used as the anode electrode, and the anode current density and cathode current density were set to 10 mA / cm². 2 Electrolysis was performed at a constant current. Figure 4A is an SEM image of the surface of the electrodeposited film, and Figure 4B is an SEM image of the cross-section of the electrodeposited film. AC2A alloy was used as the anode electrode, and the current density was 20 mA / cm². 2In the following example, no Cu was observed in the cross-section, indicating that a highly pure electrodeposited film was obtained. Thus, even when using a low-purity alloy (for example, a cast alloy with a high content of Cu, Si, Fe, etc.) as the anode electrode, a highly pure aluminum plating layer can be obtained by suppressing the anode current density.

[0063] Here, the inventors discovered that during electroplating, the metal ions that dissolve from the anode electrode change depending on the current density at the anode electrode. For example, since Cu has a higher standard electrode potential than aluminum, aluminum is preferentially ionized at the anode electrode in equilibrium, but under certain conditions, Cu is also ionized.

[0064] For example, within the material constituting the anode electrode, segregated portions of Cu and Si (crystallized portions of Cu and Si) are exposed to the surface by the ionization of aluminum. When these are removed, it becomes possible to deposit (plate) aluminum with high purity. However, when the current density of the anode electrode increases, the ionization of Cu, which is more noble than aluminum, progresses, and as a result, Cu is included in the plating. Comparing Figure 3A and Figure 4A, it can be seen that Figure 3A, which contains Cu and other elements due to the high current density of the anode electrode, has finer crystal grains. Preferably, the aluminum alloy used for the anode electrode contains 0.07 wt% or more of Cu. By using an aluminum alloy containing a predetermined amount of Cu for the anode electrode, the metallic luster on the surface of the aluminum plating layer formed on the cathode electrode is improved. It is preferable that the amount does not exceed 2.00 wt%.

[0065] Thus, the inventors discovered that grain refinement can be achieved by deliberately increasing the amount of impurities during plating. Furthermore, visual inspection of the aluminum plating layer confirmed the formation of a glossy surface. Therefore, in order to reduce the surface roughness of the plating, a material containing many impurities, such as an aluminum alloy containing Cu, Si, Fe, etc., was selected as the anode electrode material, and the anode current density was set to 40 mA / cm². 2 ~200mA / cm 2 It is desirable to do so.

[0066] Although embodiments of the present invention have been described above with reference to the attached drawings, the technical scope of the present invention is not limited to the embodiments described above. It is clear to those skilled in the art that various modifications or alterations can be conceived within the scope of the technical idea described in the claims, and these will naturally also fall within the technical scope of the present invention. [Explanation of symbols]

[0067] 1……Base material 3…Electroless plating layer 5. Aluminum plating layer 7……Anodized coating 9……Adhesion improving layer 10... Plated products

Claims

1. A method for manufacturing plated products, A process of forming an electroless Ni plating layer on a non-conductive substrate, A step of forming a Cu plating layer on the surface of the Ni plating layer, The process comprises a step of laminating an aluminum plating layer onto the surface of the Cu plating layer by electroplating, The electrolyte used when laminating the aluminum plating layer is Dialkyl sulfone, Aluminum halides, and Ammonium halide, hydrogen halide of primary amine, hydrogen halide of secondary amine, hydrogen halide of tertiary amine, general formula: R １ R ２ R ３ R ４ N-X (R １ ~R ４ It comprises at least one nitrogen-containing compound selected from the group consisting of quaternary ammonium salts represented by (where is the same or different alkyl group, and X represents a counteranion for the quaternary ammonium cation), A method for manufacturing a plated product, characterized in that, between the steps of forming a Cu plating layer on the surface of the Ni plating layer and forming the aluminum plating layer, the substrate on which the Cu plating layer is formed is immersed in the electrolyte, and then the substrate on which the Cu plating layer is formed is vibrated for 3 seconds or more.

2. The method for manufacturing a plated product according to claim 1, further comprising the step of applying an anodic oxidation treatment to the surface of the aluminum plating layer.

3. The method for manufacturing a plated product according to claim 1, characterized in that the base material is a fiber-reinforced plastic.

4. The method for manufacturing a plated product according to Claim 1, characterized in that, in the step of forming the aluminum plating layer, the member on which the Cu plating layer is formed is used as the cathode and the material of the anode is aluminum.

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