Plating apparatus and plating method for forming plating layer containing cnf

Abstract

To provide a plating apparatus for forming a plating layer containing CNF.SOLUTION: An electroplating apparatus includes a container, an anode, a cathode, a power supply, and a membrane. A plating solution containing a CNF colloid and a plating metal is contained in at least one region of the container. The anode and the cathode are disposed in the container. The cathode is disposed to face the anode. The cathode comprises a metal to be plated at least on its surface. The power supply applies a voltage between the anode and the cathode. The membrane is disposed between the anode and the cathode. The membrane does not allow CNF colloids to pass through. An example of the membrane is a cation exchange resin.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present application relates to a plating apparatus and a plating method for forming a plating layer containing cellulose nanofibers (hereinafter sometimes referred to as "CNF"). [Background technology]

[0002] CNFs are obtained by TEMPO oxidation of cellulose and are fibers with a diameter of 3 to 100 nm and a large aspect ratio. The specific strength of CNFs is five times that of steel. For this reason, CNFs are blended into tire rubber or plastics, contributing to improved toughness and flexibility. CNFs are also added to inks or cosmetics for the purpose of improving their properties. Because CNFs are derived from wood, they decompose naturally and are attracting attention as an environmentally friendly material.

[0003] Meanwhile, plating techniques are used to impart corrosion resistance, decorativeness, functionality, etc. to the surface of a substrate. Patent Document 1 describes a plating technique using CNF. However, in Patent Document 1, a plating film is merely formed on the surface of a molded body of a thermoplastic resin containing CNF, and a plating film with dispersed CNF is not formed. As such, forming a plating layer incorporating CNF has been technically difficult. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-104725 Summary of the Invention [Problem to be solved by the invention]

[0005] The present application has been made in consideration of these circumstances, and its objective is to provide a plating apparatus and plating method for forming a plating layer containing CNF. [Means for solving the problem]

[0006] The electroplating apparatus of the present application has a container in one or more regions that contains a plating solution containing a CNF colloid and a plating metal, an anode disposed in the container, a cathode disposed in the container opposite the anode and containing the metal to be plated on at least its surface, a power source that applies a voltage between the anode and the cathode, and a suppression means that suppresses adhesion of the colloid to the anode.

[0007] The electroplating method of the present application is an electroplating method that uses a plating solution containing CNF colloid and plating metal, a cathode containing the metal to be plated at least on its surface, an anode, and a container that houses the plating solution, cathode, and anode, to form a plating layer containing CNF and plating metal on the surface of the metal to be plated, and performs electroplating while suppressing adhesion of the CNF colloid to the anode.

[0008] The composite of the present application has a substrate and a plating layer that covers at least a portion of the substrate, and the plating layer contains a plating metal and CNF, and the carbon content derived from the carbon contained in the CNF of the plating layer (hereinafter sometimes simply referred to as the "carbon content of the plating layer" or the "carbon content in the plating layer") is 2.2 × 10 -3 It is 3.0 mass % or more and 3.0 mass % or less. [Effects of the Invention]

[0009] The electrolytic plating apparatus of the present application is equipped with a suppression means for suppressing adhesion of CNF colloids contained in the plating solution to the anode. The electrolytic plating method of the present application performs electrolytic plating while suppressing adhesion of CNF colloids contained in the plating solution to the anode. Therefore, the electrolytic plating apparatus and electrolytic plating method of the present application enable a plating layer containing CNF to be formed on the surface of the cathode. The composite of the present application has a carbon content of 2.2 × 10 -3 The CNF content in the plating layer is in the range of 3.0 mass % or more. Because the CNF content in the plating layer is in this wide range, the composite of the present application can be applied to products where it is desirable to have a surface with high tensile strength or high wettability, depending on the application. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is an SEM image of the surface of the plating layer of Example 1. [Figure 2] 1 is a Ni element mapping image of the surface of the plating layer of Example 1. [Figure 3] 1 is a C element mapping image of the surface of the plating layer of Example 1. [Figure 4] 1 is an O element mapping image of the surface of the plating layer of Example 1. [Figure 5] FT-IR spectra of cellulose (a) and the plating layer of Example 1 (b). [Figure 6] 1 is an SEM image of the surface of the plating layer of Example 2. [Figure 7] 10 is a Cu element mapping image of the surface of the plating layer of Example 2. [Figure 8] 10 is a C element mapping image of the surface of the plating layer of Example 2. [Figure 9] 10 is an O element mapping image of the surface of the plating layer of Example 2. [Figure 10] 10 is an SEM image of the surface of the plating layer of Example 3. [Figure 11] 10 is a Sn element mapping image of the surface of the plating layer of Example 3. [Figure 12] 10 is a C element mapping image of the surface of the plating layer of Example 3. [Figure 13] 10 is an O element mapping image of the surface of the plating layer of Example 3. [Figure 14] A graph showing the relationship between the CNF concentration in the plating solutions of Examples 4, 7, 8, and Comparative Example 1 and the total carbon content in the plating layers obtained from these plating solutions. DETAILED DESCRIPTION OF THE INVENTION

[0011] The electrolytic plating apparatus, electrolytic plating method, and composite of the present application will be described below based on embodiments and examples. The description of the electrolytic plating apparatus will also include a portion of the electrolytic plating method. When a range between two numerical values ​​is expressed using "to," these two numerical values ​​are also included in the range. Further, redundant description will be omitted as appropriate. The electrolytic plating apparatus of the present application includes a container, an anode, a cathode, a power source, and a suppression means.

[0012] The plating solution contains CNF colloids and plating metal. The plating solution may further contain additives such as surfactants, pH adjusters, and brighteners. The plating solution is contained in at least a portion of a container. If the electroplating apparatus is equipped with a diaphragm, the plating solution is contained in a cathode chamber (on the cathode side of the diaphragm), which is a portion of the container. If the electroplating apparatus is not equipped with a diaphragm, the plating solution is contained throughout the container. CNF is a cellulose fiber with a diameter of 3 nm to 100 nm and an aspect ratio of 100 or more. CNF exists in the plating solution as a negatively charged colloid.

[0013] There are no particular restrictions on the plating metal, as long as it can form a plating layer together with the CNF on the surface of the substrate, which is the material to be plated, such as the metal to be plated. Examples of plating metals include Ni, Cu, Sn, Fe, solder, Pt, Au, Ag, Zn, Cr, and Rh. The anode is placed in the container. The anode may have a plating metal on its surface so that the plating metal is supplied to the plating solution from the anode even when the plating metal in the plating solution is consumed. The cathode is placed in the container facing the anode. The cathode contains the metal to be plated on at least its surface. The cathode may be made of the metal to be plated.

[0014] The power supply applies a voltage between the anode and the cathode. In typical electrolytic plating, the power supply applies a positive voltage to the anode, but in some embodiments of the present invention, the positive voltage is applied alternately to the cathode and the anode. This embodiment will be described later. The suppression means suppresses the adhesion of CNF colloids to the anode. If plating is performed using an electrolytic plating apparatus that does not have this suppression means, negatively charged CNF colloids will deposit on the anode surface, preventing current from flowing between the anode and the cathode and preventing plating from proceeding. Examples of the suppression means include a diaphragm and a control device that controls the power supply. Multiple suppression means may be used in combination.

[0015] The diaphragm is placed between the anode and the cathode. The diaphragm may be integrated with the anode. That is, an anode integrated with the diaphragm may be used. The cathode side of the diaphragm in the container is the cathode chamber, and the anode side of the diaphragm in the container is the anode chamber. The diaphragm allows cations of the plating metal to pass through but not CNF colloids. Examples of diaphragms include diaphragms equipped with a semipermeable membrane that allows ions to pass through but not colloids, and diaphragms equipped with a cation exchange resin. The cathode chamber contains a plating solution containing CNF. The anode chamber contains an electrolyte that does not contain CNF.

[0016] When plating is performed using an electrolytic plating device equipped with a diaphragm, the cations of the plating metal present in the anode chamber pass through the diaphragm and move to the cathode chamber, where they are deposited on the cathode surface along with the CNF present in the cathode chamber, forming a plating layer containing the plating metal and CNF. The CNF colloids are negatively charged, but their charge is small. Therefore, in the cathode chamber, the CNF colloids are surrounded by the highly charged cations of the plating metal, becoming positively charged and attracted to the cathode, causing the plating metal to deposit on the cathode surface along with the CNF.

[0017] When the diaphragm is equipped with a cation exchange resin, the cations of the plating metal present in the anode chamber are initially adsorbed onto the cation exchange resin until they are saturated. The cations of the plating metal present in the cation exchange resin then migrate toward the cathode, pushed out by the cations of the plating metal continuously supplied to the cation exchange resin from the anode chamber, and also due to electrical attraction from the cathode. As the cations of the plating metal migrate toward the cathode, they surround the CNF colloids and are deposited on the cathode surface along with the CNFs. Because the gaps in the cation exchange resin are small, the CNF colloids cannot pass through the cation exchange resin.

[0018] Meanwhile, the control device that controls the power supply controls the power supply so that the positive and negative voltages are intermittently reversed. That is, this control device can repeatedly apply a positive voltage to the cathode and then to the anode, forming one reversal cycle. To completely prevent CNF colloids from depositing on the anode, the time per reversal cycle during which a positive voltage is applied to the cathode or anode is preferably several milliseconds to several seconds, for example, 5 milliseconds to 5 seconds.

[0019] When a positive voltage is applied to the cathode, the negatively charged CNF colloids are attracted to the cathode, facilitating the deposition of CNF on the cathode. When a positive voltage is applied to the anode, the cations of the plating metal are attracted to the cathode, facilitating the deposition of the plating metal on the cathode. By alternately repeating this process, a plating layer containing CNF and the plating metal is formed on the cathode surface. The charge of the CNF colloids is smaller than the charge of the plating metal cations. Therefore, to ensure that the CNF colloids are easily attracted to the cathode, it is preferable that the time per reversal cycle of the positive voltage applied to the cathode is longer than the time per reversal cycle of the positive voltage applied to the anode. Furthermore, the CNF content in the plating layer can be adjusted by changing the ratio of the time of the positive voltages applied to the anode and cathode, respectively.

[0020] An electroplating method according to an embodiment of the present application uses a plating solution, a cathode, an anode, and a container to form a plating layer containing CNF and a plating metal on the surface of a metal to be plated. The plating solution contains a CNF colloid and a plating metal. The cathode contains the metal to be plated at least on its surface. The container contains the plating solution, the cathode, and the anode. The electroplating method according to an embodiment performs electroplating while suppressing adhesion of the CNF colloid to the anode.

[0021] More specifically, electroplating is performed by placing a diaphragm between the anode and cathode, which allows passage of cations of the plating metal but not colloids, and by storing a plating solution in the cathode chamber. Alternatively, electroplating is performed while applying a voltage whose polarity is reversed intermittently between the anode and cathode. That is, electroplating is performed by intermittently repeating the process of applying a positive voltage to the cathode, then a positive voltage to the anode, and then a positive voltage to the cathode again. The aforementioned electroplating using a diaphragm may be used in combination with this electroplating in which a voltage whose polarity is reversed intermittently is applied between the anode and cathode.

[0022] The composite of the present embodiment includes a substrate and a plating layer that covers at least a portion of the substrate. The substrate is also an object to be plated. The plating layer contains a plating metal and CNF. The carbon content of the plating layer (mass of carbon contained in CNF in the plating layer / mass of the plating layer × 100) is 2.2 × 10 -3 The carbon content of the plating layer is 10% by mass or more and 3.0% by mass or less. -3 Mass% or more 10 -2 Mass% or less, e.g., 2.2 x 10 -3 Mass% or more 6.3×10 -3 When the carbon content of the plating layer is 1% by mass or more and 10% by mass or less, the tensile strength of the plating layer is high. Also, when the carbon content of the plating layer is 1% by mass or more and 10% by mass or less, the wettability of the plating layer surface is high.

[0023] The composite of the embodiment, in which the carbon content of the plating layer, i.e., the CNF content, is varied over a wide range, can be produced using the electrolytic plating apparatus or electrolytic plating method of the embodiment. That is, the electrolytic plating apparatus and electrolytic plating method of the embodiment allow the CNF content in the plating layer to be controlled over a wide range. Therefore, depending on the application, it is possible to increase the tensile strength of the plating layer or reduce the water contact angle of the plating layer surface, i.e., increase the wettability of the plating layer surface. The wettability of the surface of a plating layer containing CNF is higher than that of a plating layer not containing CNF. More specifically, the water contact angle of the plating layer surface is less than 61°, preferably 29° or less. Because the composite of the embodiment has a high wettability of the plating layer surface, it can be used in electronic circuit boards or automotive exterior components. [Example]

[0024] <Preparation of plating solution> (Preparation Example 1) A nickel sulfate solution was prepared containing 250 g / L of NiSO4·7H2O, 50 g / L of NiCl2·6H2O, 35 g / L of H3BO3 (a pH adjuster), 2 g / L of sodium saccharinate (a brightener), and 0.5 mL / L of additive (Revolt CBT103, Metal Chemical Engineering Research Institute Co., Ltd.). Separately, CNF aqueous dispersion A, containing 0.8 mass% CNF, was prepared by subjecting roughly mechanically defibrated softwood pulp to TEMPO oxidation. 0.27 L of this nickel sulfate solution was mixed with 30 g of CNF aqueous dispersion A to obtain a nickel plating solution. The CNF concentration in this nickel plating solution was 0.9 g / L.

[0025] (Preparation Example 2) A copper sulfate solution was prepared containing 240 g / L of CuSO4·5H2O, 70 g / L of H2SO4, 0.2 mL / L of 35% concentrated hydrochloric acid, 5 mL / L of an additive (Okuno Pharmaceutical Industries Co., Ltd., Top Lucina 870-MU), and 0.5 mL / L of another additive (Okuno Pharmaceutical Industries Co., Ltd., Top Lucina 870-A). 0.27 L of this copper sulfate solution was mixed with 30 g of CNF aqueous dispersion A to obtain a copper plating solution. The CNF concentration in this copper plating solution was 0.9 g / L.

[0026] (Preparation Example 3) A tin sulfate solution was prepared, containing 40 g / L of SnSO4, 100 g / L of 95% H2SO4, 35 g / L of cresol sulfonic acid, and 5 g / L of formalin. 0.27 L of this tin sulfate solution was mixed with 30 g of CNF aqueous dispersion A to obtain a tin plating solution. The CNF concentration in this tin plating solution was 0.9 g / L.

[0027] (Preparation Example 4) A nickel plating solution was obtained by mixing 1.0 L of the nickel sulfate solution from Preparation Example 1 with 33.3 g of CNF aqueous dispersion B (Dai-ichi Kogyo Seiyaku, Rheocrysta I-2SX) containing 0.3 mass% of CNF with a fiber diameter of approximately 3 nm produced by the TEMPO oxidation method. The CNF concentration in this nickel plating solution was 0.1 g / L.

[0028] (Preparation Example 5) A nickel plating solution was obtained by mixing 1.0 L of the nickel sulfate solution of Preparation Example 1 and 133.3 g of CNF aqueous dispersion B. The CNF concentration in this nickel plating solution was 0.4 g / L.

[0029] (Preparation Example 6) A nickel plating solution was obtained by mixing 1.0 L of the nickel sulfate solution of Preparation Example 1 and 266.7 g of CNF aqueous dispersion B. The CNF concentration in this nickel plating solution was 0.6 g / L.

[0030] <Electrolytic plating> Example 1 A 2 L rectangular quartz glass container (hereinafter the same) was placed in a diaphragm-shaped container, and the container was divided into an anode chamber on the anode side and a cathode chamber on the cathode side by placing a cation exchange resin (DuPont Japan Co., Ltd., NAFION NRE-212 (hereinafter the same)) as a diaphragm. The anode chamber contained a Ni anode and the nickel sulfate solution of Preparation Example 1 at approximately 50°C, while the cathode chamber contained a Cu cathode and the nickel plating solution of Preparation Example 1 at approximately 50°C. The current was 2 A and the current density was 7 A / dm 2Electrolytic plating of Example 1 was performed while applying a positive voltage for 30 minutes, repeating one cycle of 4 seconds to the cathode and 2 seconds to the anode, so that the plating layer of Example 1 was formed on the surface of Cu. The thickness of this plating layer was 40 μm. The thickness of the plating layer was measured with a micrometer (Mitutoyo Corporation, MDC-25SB) (the same applies below).

[0031] FIG. 1 is an SEM image of the surface of the plating layer of Example 1. The SEM image was acquired using a scanning electron microscope (SEM) (field-emission scanning electron microscope, JEOL Ltd., JSM-7100F / TTLS / EDS) (the same applies below). As shown in FIG. 1, white fibrous aggregates were observed in the plating layer of Example 1. FIGS. 2, 3, and 4 are element mapping images of Ni, C (carbon), and O (oxygen) on the surface of the plating layer of Example 1. In these images, light-colored (close to white) areas indicate the presence of each element. As shown in FIGS. 2 to 4, the plating layer of Example 1 was found to contain Ni, which is the plating metal, and carbon and oxygen, which constitute CNF. Furthermore, quantitative analysis (ZAF method) revealed that the carbon content of the plating layer of Example 1 was 3.0% by mass.

[0032] Figures 5(a) and 5(b) show the FT-IR spectra of the cellulose and the plating layer of Example 1, respectively. Figure 5(a) is a graph obtained from Bio-Rad Laboratories, Inc.'s Know It All TM 5(b) shows the FT-IR spectrum of RAYOCORD XG*CELLULOSE, a cellulose standard sample registered in Informatics System 2013. The FT-IR in FIG. 5(b) was measured using a Fourier transform infrared spectrophotometer (JASCO Corporation, FT / IR-6100). As shown in FIG. 5(b), the FT-IR spectrum of the plating layer of Example 1 shows a peak in the 900-1200 cm -1 , 1400~1500cm -1 , and 2900-3300 cm -1 Peaks derived from plants such as cellulose were observed in the peaks. From the above, it was found that the plating layer of Example 1 contained CNF.

[0033] Example 2 A cation exchange resin diaphragm was placed inside the container to separate the anode and cathode sides. A Cu anode and the copper sulfate solution of Preparation Example 2 at approximately 25°C were placed in the anode side, and a SUS cathode and the copper plating solution of Preparation Example 2 at approximately 25°C were placed in the cathode side. The current was 2 A, and the current density was 7 / dm 2 The electrolytic plating of Example 2 was performed while applying a voltage in a fixed direction between the anode and cathode for 30 minutes so as to obtain the plating layer of Example 2 formed on the surface of SUS. Note that the positive voltage applied to the anode was not reversed.

[0034] Figure 6 is an SEM image of the surface of the plating layer of Example 2. As shown in Figure 6, white fibrous aggregates were also observed in the plating layer of Example 2. Figures 7, 8, and 9 are element mapping images of Cu, C, and O, respectively, on the surface of the plating layer of Example 2. As shown in Figures 7 to 9, it was found that the plating layer of Example 2 contains Cu, which is the plating metal, and carbon and oxygen, which constitute CNF. From the above, it was found that Cu plating also contains CNF in the plating layer, just like Ni plating.

[0035] Example 3 A cation exchange resin diaphragm was placed inside the container to separate it into an anode side and a cathode side. A Sn anode and the tin sulfate solution of Preparation Example 3 at 20°C were placed in the anode side, and a Cu cathode and the tin plating solution of Preparation Example 3 at 20°C were placed in the cathode side. The electrolysis time was then changed from 30 minutes to 20 minutes, and the plating layer of Example 3 formed on the surface of Cu was obtained in the same manner as in Example 2. Because the thickness of the plating layer was nonuniform, it was impossible to measure the thickness of this plating layer.

[0036] Figure 10 is an SEM image of the surface of the plating layer of Example 3. As shown in Figure 10, white fibrous aggregates were also observed in the plating layer of Example 3. Figures 11, 12, and 13 are element mapping images of Sn, C, and O, respectively, on the surface of the plating layer of Example 3. As shown in Figures 11 to 13, it was found that the plating layer of Example 3 contains tin, which is the plating metal, and carbon and oxygen, which constitute CNF. From the above, it was found that Sn plating also contains CNF in the plating layer, just like Ni plating.

[0037] Example 4 A cation exchange resin diaphragm was placed in the container to separate the anode and cathode sides. The anode side contained a Ni anode and the nickel sulfate solution of Preparation Example 1 at approximately 50°C, while the cathode side contained a SUS cathode and the nickel plating solution of Preparation Example 4 at approximately 50°C. The current was 2.7 A, the current density was 2 / dm 2 Electrolytic plating of Example 4 was performed while applying a voltage in a fixed direction between the anode and cathode for 38 minutes so as to obtain a plating layer of Example 4 formed on the surface of SUS. The thickness of this plating layer was 10 μm.

[0038] Example 5 A Ni anode, a SUS cathode, and the nickel plating solution of Preparation Example 5 at approximately 50°C were placed in a container. The current was 2.7 A, the current density was 2 / dm 2 The electrolytic plating of Example 5 was performed while applying a positive voltage for 65 minutes, repeating one cycle of 4 seconds to the cathode and 2 seconds to the anode, so as to obtain a plating layer of Example 5 formed on the surface of SUS. The thickness of this plating layer was 10 μm.

[0039] Example 6 A cation exchange resin diaphragm was placed in the container to separate the anode and cathode sides. The anode side contained a Ni anode and the nickel sulfate solution of Preparation Example 1 at approximately 50°C, while the cathode side contained a SUS cathode and the nickel plating solution of Preparation Example 5 at approximately 50°C. The current was 2.7 A, the current density was 2 / dm 2The electrolytic plating of Example 6 was performed while applying a positive voltage for 38 minutes, repeating one cycle of 4 seconds to the cathode and 2 seconds to the anode, so as to obtain a plating layer of Example 6 formed on the surface of SUS. The thickness of this plating layer was 10 μm.

[0040] Example 7 The plating layer of Example 7 formed on the surface of SUS was obtained in the same manner as in Example 4, except that the nickel plating solution of Preparation Example 5 at approximately 50°C was placed on the cathode side of the container and the electrolysis time was set to 41 minutes. The thickness of this plating layer was 10 μm.

[0041] Example 8 The plating layer of Example 8 formed on the surface of SUS was obtained in the same manner as in Example 4, except that the nickel plating solution of Preparation Example 6 at approximately 50°C was placed on the cathode side of the container and the electrolysis time was set to 24.3 minutes. The thickness of this plating layer was 10 μm.

[0042] (Comparative Example 1) A CNF-free nickel plating layer was formed on the surface of SUS using the following procedure. A Ni anode, a SUS cathode, and the nickel sulfate solution of Preparation Example 1 at approximately 50°C were placed in a container. The plating layer of Comparative Example 1 was then obtained in the same manner as in Example 8. The thickness of this plating layer was 10 μm.

[0043] (Comparative Example 2) A Ni anode, a Cu cathode, and the nickel plating solution of Preparation Example 1 at about 50°C were placed in a container. The current was 2 A, and the current density was 1.5 / dm 2 A positive voltage was applied to the anode so that a plating layer containing CNF was formed on the surface of the Cu. However, after about one minute of voltage application, CNF colloids precipitated on the anode surface, current flow ceased, and the amount of CNF dispersed in the plating solution decreased. As a result, a plating layer containing CNF could not be formed on the surface of the Cu.

[0044] The plating treatments of Examples 1 to 8 and Comparative Example 1 are shown in Table 1. [Table 1]

[0045] <Evaluation of plating layer> (Wettability of plated surface) Due to the presence of hydroxy groups in CNF, the surface of a metal plating layer containing CNF is thought to have higher wettability than the surface of a metal plating layer not containing CNF. Therefore, the wettability of the surface of the plating layer in Example 1 was evaluated. This wettability evaluation was performed using a contact angle meter (PG-X, Matsubo Co., Ltd.) in static mode to measure the contact angle of the surface of the plating layer with water when approximately 2 μL of distilled water was dropped onto the surface. The contact angle of the surface of the plating layer in Example 1 with water was 29°. The contact angles of the surface of the Cu cathode before plating and the surface of the plating layer of a composite in which a CNF-free Ni plating layer approximately 1 μm thick was formed on the Cu cathode were 79° and 61°, respectively. The metal plating layer containing CNF reduced the contact angle of the surface with water, i.e., improved wettability.

[0046] Therefore, the composite of the present application, which includes a substrate and a plating layer containing CNF, can be applied to electronic substrates or automotive exterior parts, which preferably have a surface with high wettability. The surface of the plating layer of the composite of the present application exhibits high wettability, with a contact angle with water of less than 61°. Therefore, when the composite of the present application is applied to an electronic substrate, metals such as solder easily adhere to the surface. Furthermore, when the composite of the present application is applied to an automotive exterior part, the adhesion strength of the paint is improved.

[0047] (Surface roughness of plated surface) The surface roughness of the plating layer of Example 1 was evaluated using a surface roughness contour measuring instrument (Kosaka Laboratory, DSF1000) under the conditions of cutoff: 0.8 mm, E. length: 4 mm, and S. length: 0.8 mm. The arithmetic mean surface roughness (Ra) and ten-point mean roughness (Rz) of the surface of the plating layer of Example 1 were 5.87 μm and 33.8 μm, respectively. The moderately large surface roughness of the metal plating layer containing CNF is thought to be one of the factors contributing to improved wettability. The arithmetic mean surface roughness (Ra) and ten-point mean roughness (Rz) of the surface of a Ni plating layer with a thickness of approximately 1 μm and no CNF formed on a Cu electrode were 0.004 μm and 0.9 μm, respectively.

[0048] (Tensile strength of plating layer) The tensile strength of the plating layers of Examples 4, 7, and Comparative Example 1 was evaluated using a universal testing machine (Orientec, RTC-1310, load cell rating 1000 N) according to the following procedure. A sample measuring 10 mm in width, 65 mm in length, and 10 μm in thickness was cut out from each plating layer. The sample was fixed in the chuck of the universal testing machine with a gripping width of 25 mm and pulled at a speed of 2 mm / min to measure the maximum point load. Each sample was measured four times, and the average value was taken as the maximum point load for that sample.

[0049] The maximum point loads of the plating layers in Example 4, Example 7, and Comparative Example 1 were 118 N, 105 N, and 95 N, respectively. A comparison of the maximum point loads of Examples 4 and 7 with those of Comparative Example 1 revealed that the inclusion of CNF in the plating layer increased the tensile strength. Furthermore, a comparison of the maximum point loads of Examples 4 and 7 revealed that the tensile strength did not necessarily increase as the amount of CNF contained in the plating layer increased, and that there was a range of CNF content at which the tensile strength was high.

[0050] This preferred CNF content range cannot be directly measured. Therefore, we decided to convert this preferred CNF content range into a carbon content range. Using a carbon-sulfur analyzer (Horiba, Ltd., EMIY-920VY), the carbon content in the plating layers of Examples 4, 7, and 8, and Comparative Example 1, was measured. Note that carbon was also present in the plating layer of Comparative Example 1, whose plating solution did not contain CNF. It is believed that the carbon contained in the plating layer of Comparative Example 1 is not derived from the carbon contained in the CNF, but from carbon contained in the sodium saccharinate and other substances contained in the plating solution.

[0051] Therefore, the carbon content of the plating layers of Example 4, Example 7, and Comparative Example 1 was calculated using the following procedure. First, a graph was created to show the relationship between the CNF concentration in the plating solution and the total carbon content in the plating layer, with the CNF concentration (g / L) in the plating solutions of Example 4, Example 7, Example 8, and Comparative Example 1 on the horizontal axis and the total carbon content (mass%) in the plating layers obtained from these plating solutions and measured above on the vertical axis. In the graph, Example 4 is represented by a square (■), Example 7 by a triangle (△), Example 8 by a diamond (◆), and Comparative Example 1 by a circle (◯). The results are shown in Figure 14.

[0052] As shown in Figure 14, the relationship between the CNF concentration in the plating solution and the total carbon content in the plating layer was a linear function. In other words, when the CNF concentration in the plating solution was 0, the carbon content in the plating layer was 7.9 × 10 -3 % by mass is the carbon content that is not derived from the carbon contained in the CNF. Therefore, from the total carbon content in the plating layer, the carbon content that is not derived from the carbon contained in the CNF, 7.9 × 10 -3 The value obtained by subtracting the mass % is the carbon content derived from the carbon contained in the CNF in the plating layer.

[0053] Therefore, the total carbon content in each of the plating layers in Example 4 and Example 7 was 10.1 × 10 -3 mass% and 14.2 x 10 -3 The carbon content derived from the carbon contained in the CNF in the plating layers of Examples 4 and 7 was calculated from the mass % and was 2.2 × 10 -3mass% and 6.3 x 10 -3 In other words, the carbon content of the coating layer is 2.2 × 10 -3 Mass% or more 6.3×10 -3 When the content was 0.05 mass % or less, the tensile strength was as high as 105N to 118N.

[0054] CNF is CH 10 O5 is the minimum repeating unit. C6H 10 Since the molecular weight of O5 is 162 and the total atomic weight of C6 is 72, the CNF content = carbon content × 162 / 72. Therefore, multiplying the carbon content calculated using the above method by 162 / 72 can be converted to the CNF content (mass%) in the plating layer. Note that the metal content (mass%) in the plating layer is 100 - the CNF content in the plating layer.

[0055] The CNF volume ratio (vol %) in the plating layer can be calculated by dividing the volume of CNF in the plating layer by the volume of CNF in the plating layer plus the volume of the plating metal in the plating layer. In other words, the CNF volume ratio in the plating layer is calculated by dividing the CNF content in the plating layer by the density of CNF in the plating layer by the density of CNF in the plating layer plus the content of the plating metal in the plating layer by the density of the plating metal in the plating layer. When the density of Ni is 8.9 g / cm, the CNF volume ratio in the plating layer is calculated by dividing the CNF content in the plating layer by the density of CNF in the plating layer plus the density of the plating metal in the plating layer. 3 , the density of CNF is 1.4 g / cm 3 Assuming that the carbon content in the plating layer of Example 1 is 3.0 mass%, the CNF volume ratio in the plating layer of Example 1 is 32 volume%. Also, the carbon content in the plating layer of Example 4 is 2.2 × 10 -3 Since this is expressed in mass%, the CNF volume fraction ratio in the plating layer of Example 4 is 3.2 × 10 -2 Volume %.

Claims

1. a container containing a plating solution containing a CNF colloid and a plating metal in a part or more of its area; an anode disposed within the vessel; a cathode that is disposed in the container so as to face the anode and that contains the metal to be plated at least on its surface; a power source that applies a voltage between the anode and the cathode; a suppression means for suppressing adhesion of the colloid to the anode; An electrolytic plating apparatus having:

2. In claim 1, the suppression means is a diaphragm that is installed between the anode and the cathode in the container and that allows cations of the plating metal to pass through but does not allow the colloid to pass through; The plating solution is contained on the cathode side of the diaphragm.

3. In claim 2, An electrolytic plating apparatus in which the diaphragm is provided with a cation exchange resin.

4. In claim 1, The electrolytic plating apparatus, wherein the suppression means is a control device that controls the power supply so as to intermittently reverse the positive and negative polarities of the voltage.

5. In any one of claims 1 to 4, The electrolytic plating apparatus, wherein the plating metal is Ni, Cu, or Sn.

6. An electrolytic plating method for forming a plating layer containing CNF and the plating metal on the surface of the metal to be plated, using a plating solution containing a CNF colloid and a plating metal, a cathode containing the metal to be plated at least on its surface, an anode, and a container for accommodating the plating solution, the cathode, and the anode, comprising: The electrolytic plating method comprises: performing electrolytic plating while suppressing adhesion of the colloid to the anode;

7. In claim 6, A method for electroplating in which a diaphragm through which cations of the plating metal can pass but which the colloid cannot pass is placed between the anode and the cathode, and the plating solution is contained on the cathode side of the diaphragm.

8. In claim 6, The electrolytic plating method involves applying a voltage between the anode and the cathode, the voltage being reversed between positive and negative polarities intermittently.

9. In claim 8, The electrolytic plating method, wherein the time per one reversal cycle of the positive voltage applied to the cathode is longer than the time per one reversal cycle of the positive voltage applied to the anode.

10. In any one of claims 6 to 9, The electrolytic plating method, wherein the plating metal is Ni, Cu, or Sn.

11. A substrate and a plating layer covering at least a portion of the substrate, the plating layer contains a plating metal and CNF, The carbon content derived from carbon contained in the CNF of the plating layer is 2.2 × 10 －３ % by mass or more and 3.0% by mass or less.

12. In claim 11, A composite in which the contact angle of the surface of the plating layer with water is less than 61°.

13. An electronic substrate or an exterior automotive part comprising the composite of claim 11 or 12.

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