Part of electronic components and manufacturing method thereof, and electronic components

Abstract

To provide a part material of an electronic component having a plating film that can reduce cracks that occur in a conductive base material. [Solution] A material for an electronic component includes a conductive base material and a plating film covering at least a portion of the conductive base material. The plating film has a first nickel plating layer closer to the conductive base material and a second nickel plating layer adjacent to the first nickel plating layer, and when viewed in a cross section along a first direction perpendicular to the surface of the conductive base material covered by the plating film, the average grain size A1 of crystal grains G1 constituting the first nickel plating layer is smaller than the average grain size A2 of crystal grains G2 constituting the second nickel plating layer.

Description

[Technical Field]

[0001] The present disclosure relates to a material for an electronic component, a manufacturing method thereof, and an electronic component. [Background technology]

[0002] Patent Document 1 describes a plated product in which a multilayer plating film is formed on a substrate made of a conductive metal, the plated product having, in that order, a porous plating layer mainly composed of Ni or Cu and a surface plating layer mainly composed of Au or Ag on the substrate, with numerous holes formed on the surface of the multilayer plating film. Furthermore, Patent Document 1 lists applications of such plated products as electrical components in which the portions on which the multilayer plating film is formed serve as electrical contacts. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2013 / 094766 Summary of the Invention [Problem to be solved by the invention]

[0004] One aspect of the present disclosure provides a material for an electronic component having a plating film that can reduce cracks that occur in a conductive substrate, and a method for manufacturing the same. Another aspect of the present disclosure provides an electronic component having such a material. [Means for solving the problem]

[0005] A material for an electronic component according to one aspect of the present disclosure is a material for an electronic component comprising a conductive base material and a plating film covering at least a portion of the conductive base material, wherein the plating film has a first nickel plating layer closer to the conductive base material and a second nickel plating layer adjacent to the first nickel plating layer, and when viewed in a cross section along a first direction perpendicular to the surface of the conductive base material covered by the plating film, the average grain size A1 of crystal grains G1 constituting the first nickel plating layer is smaller than the average grain size A2 of crystal grains G2 constituting the second nickel plating layer.

[0006] A material for an electronic component according to one aspect of the present disclosure is a material for an electronic component comprising a conductive base material and a plating film covering at least a portion of the conductive base material, wherein the plating film has a first nickel plating layer closer to the conductive base material and a second nickel plating layer adjacent to the first nickel plating layer, and when viewed in a cross section along a first direction perpendicular to the surface of the conductive base material covered by the plating film, among the crystal grains G1 constituting the first nickel plating layer, the grain sizes of the crystal grains G1 in contact with the conductive base material are all less than 0.50 μm, and the crystal grains G2 constituting the second nickel plating layer include those having a grain size of 0.50 μm or more.

[0007] An electronic component according to one aspect of the present disclosure includes a part of the electronic component described above.

[0008] A method for manufacturing a component of an electronic component according to one aspect of the present disclosure is a method for manufacturing a component of an electronic component that includes a conductive base material and a plating film that covers at least a portion of the conductive base material, and includes forming a roughened nickel plating film so as to cover at least a portion of the surface of the conductive base material, and forming a matte nickel plating film so as to cover at least a portion of the surface of the roughened nickel plating film. [Effects of the Invention]

[0009] According to one aspect of the present disclosure, it is possible to provide a material for an electronic component having a plating film that can reduce cracks that occur in a conductive base material, and a method for manufacturing the same. According to one aspect of the present disclosure, it is possible to provide an electronic component having such a material for the electronic component. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a cross-sectional view showing an example of a part of an electronic component (connector). [Figure 2] FIG. 2 is an enlarged cross-sectional view of the surface area of ​​a part of an electronic component (connector). [Figure 3] 1A is an enlarged cross-sectional view of a region P2 of the second nickel plating layer, and FIG. 1B is an enlarged cross-sectional view of a region P1 of the first nickel plating layer. [Figure 4] FIG. 2 is a cross-sectional view of a crystal grain G1 or a crystal grain G2 that constitutes the first nickel plating layer or the second nickel plating layer. [Figure 5] FIG. 10 is a perspective view showing another example of a part of an electronic component (a part of a connector). [Figure 6] FIG. 1 is a perspective view showing a plug connector, which is an example of an electronic component (connector). [Figure 7] FIG. 2A is a top view of the plug connector, and FIG. 2B is a bottom view of the plug connector. [Figure 8] FIG. 2 is a perspective view of the plug connector from which the first shell and the cable have been removed. [Figure 9] 7A is a cross-sectional view taken along line IXa-IXa in FIG. 7A, and FIG. 7B is a cross-sectional view taken along line IXb-IXb in FIG. 7B. [Figure 10] FIG. 10 is a perspective view of a receptacle connector, which is another example of a connector. [Figure 11] 1A is a top view of the receptacle connector, and FIG. 1B is a bottom view of the receptacle connector. [Figure 12] 1A and 1B are cross-sectional views showing the mated state of the plug connector and the receptacle connector. [Figure 13] FIG. 10 is a perspective view showing yet another example of an electronic component (connector). [Figure 14] FIG. 1 is a plan view of plated products produced in an example and comparative examples. [Figure 15] FIG. 10 is a diagram of a plated product with a bent portion formed thereon. [Figure 16] 14A is a scanning electron microscope photograph showing the surface of the bent portion of Example 1 (cross section at the intersection of center line CL and cutting line CT in FIG. 14) at a magnification of 100x. 14B is a scanning electron microscope photograph showing the surface of the bent portion of Example 1 at a magnification of 1000x. [Figure 17] (A) is a scanning electron microscope photograph showing a cross section of a bent portion of Example 1 (a cross section of a portion corresponding to the intersection of center line CL and cutting line CT in FIG. 14) at a magnification of 200 times. (B) is a scanning electron microscope photograph showing area RE1 of (A) at a magnification of 5000 times. [Figure 18] 18 is an electron backscatter diffraction (EBSD) map of the scanning electron microscope image shown in FIG. 17B, obtained by EBSD. [Figure 19] EBSD map of the cross section of the plated product of Example 1 shows crystal grains G1 (Nos. 1 to 5) whose sizes were measured. EBSD map of the cross section of the plated product of Example 1 shows crystal grains G1 (Nos. 6 to 10) whose sizes were measured. [Figure 20] EBSD map of the cross section of the plated product of Example 1 shows crystal grains G2 (Nos. 1 to 5) whose sizes were measured. EBSD map of the cross section of the plated product of Example 1 shows crystal grains G2 (Nos. 6 to 10) whose sizes were measured. [Figure 21] FIG. 1 shows ten crystal grains G1 measured using an EBSD map. [Figure 22] FIG. 10 shows the measurements of 10 crystal grains G2 using an EBSD map. [Figure 23] 14A is a scanning electron microscope photograph showing the surface of the bent portion of Comparative Example 1 (the intersection of the center line CL and the cutting line CT in FIG. 14) at a magnification of 100x. FIG. 14B is a scanning electron microscope photograph showing the surface of the bent portion of Comparative Example 1 at a magnification of 1000x. [Figure 24]14A is an electron microscope photograph showing a cross section of a bent portion of Comparative Example 1 (a cross section of a portion corresponding to the intersection of center line CL and cutting line CT in FIG. 14) at a magnification of 200 times. FIG. 14B is an electron microscope photograph showing area RE1 of FIG. 14A at a magnification of 5000 times. [Figure 25] 25 is an electron backscatter diffraction (EBSD) map of the scanning electron microscope image shown in FIG. 24(B) obtained by EBSD. [Figure 26] 14A is a scanning electron microscope photograph showing the surface of the bent portion of Comparative Example 2 (cross section at the intersection of center line CL and cutting line CT in FIG. 14) at a magnification of 100x. FIG. 14B is a scanning electron microscope photograph showing the surface of the bent portion of Comparative Example 2 at a magnification of 1000x. DETAILED DESCRIPTION OF THE INVENTION

[0011] Several embodiments will be described in detail below with reference to the drawings. In the description, identical elements or elements having the same functions are denoted by the same reference numerals, and redundant description will be omitted. The following embodiments are all examples for explaining the present disclosure and are not intended to limit the present invention to the following content. In the description, the numerical range exemplified as "a to b" is a numerical range inclusive of a and b, with a lower limit of a and an upper limit of b. In numerical ranges described in stages, a numerical range in which the upper or lower limit of one numerical range is replaced with the upper or lower limit of another numerical range described in stages is also included in the present disclosure. In numerical ranges described in the embodiments, a numerical range in which the upper or lower limit of that numerical range is replaced with a value shown in the examples is also included in the present disclosure. When multiple materials are exemplified, one of the materials may be used alone, or multiple materials may be used in combination.

[0012] The electronic components disclosed herein constitute electronic or electric circuits and are components of electronic devices and electric devices. Electronic components have functions such as controlling, converting, transmitting, detecting, and connecting the flow of electric signals and power. Examples of electronic components include passive components such as capacitors, resistors, transformers, and inductors; connecting components such as switches, touch panels, and connectors; conversion components such as acoustic components, sensors, and actuators; switching power supplies; high-frequency components; and cables. A component of an electronic component is one of multiple members constituting the electronic component and includes a conductive base material and a plating film that coats at least a portion of the conductive base material.

[0013] A connector, an example of an electronic component, mechanically connects multiple elements and transmits electrical signals, power, or optical signals converted to electrical signals. The connector may be an electrical connector that makes electrical connections, or an optical connector that transmits electrical signals converted from optical signals. Examples of electrical connectors include connectors consisting of a single component connected to a cable or board (e.g., a terminal for a board), connectors for electronic devices consisting of two or more components, such as a male connector and a female connector, and power connectors. Furthermore, when a connector consists solely of a terminal made of a conductive material and the terminal is connected to another electronic or electrical component, the terminal is also considered a type of electrical connector. A power supply connector connected to an electric vehicle is also considered a type of electrical connector. A connector that electrically connects a first component to a second component is also considered a type of electrical connector.

[0014] A connector member of the present disclosure is one of the multiple components constituting the connector described above, and has a conductive base material. Examples of connector members include contacts (terminals) such as signal terminals, ground terminals, and power terminals, ground bars, bus bars, pins, and shells. Connector covers and fasteners are also included in connector members of the present disclosure when they have a conductive base material. Connector members are not limited to the above examples. A connector member may be a connector terminal or a connector shell.

[0015] A part of the connector comprises a conductive substrate and a plating film that coats at least a portion of the conductive substrate. The conductive substrate may be made of a metal or an alloy. Examples of metals include copper, and examples of alloys include copper alloys. Examples of copper alloys include brass, phosphor bronze, and beryllium copper. The plating film that coats the conductive substrate also has electrical conductivity.

[0016] Contact 10, which is an example of a component of a connector shown in Figure 1, includes conductive substrate 20 and plating film 30 that entirely covers conductive substrate 20. Figure 1 shows a cross section along a direction (first direction) perpendicular to the surface of conductive substrate 20 covered by plating film 30. Because plating film 30 is thinner than conductive substrate 20, the structure of plating film 30 is not shown in Figure 1. When a cross section near the surface of contact 10 such as that shown in Figure 1 is observed at a magnification of, for example, 5000 times using a scanning electron microscope (SEM), a cross section such as that shown in Figure 2 is observed.

[0017] 2, the plating film 30 has a first nickel plating layer 31 closer to the conductive base material 20, a second nickel plating layer 32 adjacent to the first nickel plating layer 31, and a gold plating layer 33 adjacent to the second nickel plating layer 32. That is, the contact 10 has, from the inside to the surface, the conductive base material 20, the first nickel plating layer 31, the second nickel plating layer 32, and the gold plating layer 33, in this order.

[0018] The plating film 30 does not need to include a copper plating layer or a copper alloy plating layer. Copper diffuses more easily than nickel, so if the plating film 30 includes a copper plating layer or a copper alloy plating layer, the surface of the plating film 30 tends to be easily discolored and corroded. By not including a copper plating layer or a copper alloy plating layer in the plating film 30, discoloration can be suppressed and corrosion resistance can be improved.

[0019] In the cross section shown in Fig. 2, the direction (first direction) perpendicular to the surface 20a of the conductive base material 20 covered by the plating film 30 is the y direction. The thicknesses of the plating film 30 and the first nickel plating layer 31, second nickel plating layer 32, and gold plating layer 33 constituting the plating film 30 can be determined by measuring their respective lengths along the y direction. If the thickness varies, the thickness of the plating film 30 or each layer can be measured at 10 arbitrarily selected locations in the cross section shown in Fig. 2, and the arithmetic mean value of each measurement can be used as the thickness of the plating film 30 or each layer.

[0020] The thickness T1 of the first nickel plating layer 31 may be 0.1 μm or more, 0.2 μm or more, or 0.3 μm or more. Increasing the thickness T1 (by increasing the thickness T1) can sufficiently increase the hardness of the surface of one material of the connector. The thickness T1 of the first nickel plating layer 31 may be 1.0 μm or less, 0.9 μm or less, or 0.7 μm or less. Reducing the thickness T1 (by reducing the thickness T1) can reduce the tensile stress generated on the surface of the plating film 30 when the contact 10 is deformed.

[0021] The thickness T2 of the second nickel plating layer 32 may be 0.5 μm or more, 1.0 μm or more, or 1.2 μm or more. Increasing the thickness T2 can improve corrosion resistance and wear resistance. The thickness T2 of the second nickel plating layer 32 may be 3.0 μm or less, 2.5 μm or less, or 2.0 μm or less. Reducing the thickness T2 can reduce the tensile stress generated on the surface of the plating film 30 when the contact 10 is deformed.

[0022] The thickness T2 of the second nickel plating layer 32 may be greater than the thickness T1. This improves corrosion resistance and wear resistance and allows for greater design freedom. The sum of the thicknesses T1 and T2 may be 4.0 μm or less, 3.5 μm or less, or 3.0 μm or less. By reducing the sum of the thicknesses T1 and T2, the tensile stress generated on the surface of the plating film 30 when the contact 10 is deformed can be reduced.

[0023] The thickness T3 of the gold plating layer 33 may be 0.1 to 0.8 μm, or 0.2 to 0.5 μm. The total thickness of the plating film 30 may be 4.5 μm or less, 4.2 μm or less, or 4.0 μm or less. By reducing the total thickness of the plating film 30, it is possible to reduce the tensile stress that occurs on the surface of the plating film 30 when the contact 10 is deformed.

[0024] The first nickel plating layer 31 and the second nickel plating layer 32 may be composed of crystal grains of one or both of nickel and nickel alloy, or may be composed of nickel crystal grains. As shown in FIG. 3A, the second nickel plating layer 32 is composed of crystal grains G2, and as shown in FIG. 3B, the first nickel plating layer 31 is composed of crystal grains G1. The crystal grains G1 and G2 may be composed of nickel alone or a nickel alloy. The shapes and sizes of the crystal grains G2 and G1 shown in FIGS. 3A and 3B are examples, and the crystal grains G2 and G1 may have shapes and sizes different from those shown in FIGS. 3A and 3B.

[0025] The crystal grains G2 may be oriented so that their longitudinal direction is along the y direction (first direction). Note that it is not necessary for the longitudinal direction of all crystal grains G2 to be along the y direction; it is sufficient if there are more crystal grains G2 whose longitudinal direction is along the y direction than in the x direction (direction parallel to the coating surface 20a; second direction), which is perpendicular to the y direction. When the number of crystal grains G2 aligned along the y direction is greater, the crystal grains G2 are said to be oriented along the y direction (first direction). By aligning the crystal grains G2 along the y direction, the hardness of the surface of the contact 10 can be further increased. The crystal grains G1 may also be oriented along the y direction (first direction), like the crystal grains G2. This can further increase the hardness of the surface of the contact 10.

[0026] The average grain size A1 of the crystal grains G1 may be smaller than the average grain size A2 of the crystal grains G2. The average grain size A1 may be less than 0.4 μm, less than 0.35 μm, less than 0.30 μm, or less than 0.28 μm. The lower limit of the average grain size A1 may be 0.10 μm. The average grain size A2 may be 0.40 μm or more, or 0.45 μm or more. The upper limit of the average grain size A2 may be 0.80 μm or 0.70 μm.

[0027] In this way, since the crystal grain G1 in the contact 10, which is closer to the conductive substrate 20, is smaller than the crystal grain G2, when the contact 10 comes into contact with another component or when the contact 10 is deformed, the concentration of stress locally on the conductive substrate 20 is alleviated, thereby reducing cracks that occur in the conductive substrate 20.

[0028] The average grain size A1 can be measured by the following procedure. From an EBSD map (magnification: e.g., 5000x) of the cross section of the plating film 30 obtained by electron backscatter diffraction (EBSD), ten crystal grains G1 that are in contact with the conductive substrate 20 are arbitrarily selected. As shown in FIG. 4, the length H of the selected crystal grains G1 along the y direction and the length W of the selected crystal grains G1 along the x direction are measured. The lengths H and W can be determined by measuring the size of the crystal grains G1 in a photograph obtained by taking the EBSD map and comparing them with the scale bar. The grain size of the crystal grain G1 is the average value ((H + W) / 2) of the lengths H and W. The grain sizes of the ten crystal grains G1 are determined in this manner, and the arithmetic average value of these is defined as the average grain size A1. That is, the average grain size A1 is the arithmetic average value of the grain sizes of the crystal grains G1 that constitute the first nickel plating layer 31 and are in contact with the conductive substrate 20.

[0029] The average grain size A2 can be determined in the same manner as the average grain size A1. Specifically, in an EBSD map (magnification, for example, 5000x) of the cross section of the plating film 30, ten crystal grains G2 at least partially exposed on the surface of the second nickel plating layer 32 opposite the first nickel plating layer 31 (crystal grains G2 in contact with the gold plating layer 33) are arbitrarily selected. Then, as shown in FIG. 4, the length H of the selected crystal grains G2 along the y direction and the length W of the selected crystal grains G2 along the x direction are measured. The lengths H and W can be determined by measuring the size of the crystal grains G2 in a photograph obtained by taking the EBSD map and comparing them with the scale bar. The grain size of the crystal grain G2 is the average value ((H + W) / 2) of the lengths H and W. The grain sizes of the ten crystal grains G2 are determined in this manner, and the arithmetic average of these values ​​is defined as the average grain size A2. That is, the average grain size A2 is the arithmetic mean value of the grain size of the crystal grains G2 that constitute the second nickel plating layer 32 and that are at least partially exposed on the surface opposite to the first nickel plating layer 31.

[0030] The ratio of the average particle size A2 to the average particle size A1 may be 1.3 or more, 1.4 or more, or 1.5 or more. The ratio of the average particle size A2 to the average particle size A1 may be 4.0 or less, 3.5 or less, or 3.0 or less.

[0031] Of the crystal grains G1 constituting the first nickel plating layer 31, the grain size of the crystal grains G1 in contact with the conductive base material 20 may be less than 0.50 μm, less than 0.45 μm, or less than 0.40 μm. The small size of the crystal grains G1 in contact with the conductive base material 20 sufficiently prevents scratches on the surface of the conductive base material 20 when the contact 10 comes into contact with another member or is deformed. The first nickel plating layer 31 does not need to include crystal grains G1 with a grain size of 0.50 μm or more.

[0032] The crystal grains G2 constituting the second nickel plating layer 32 may include those with a grain size of 0.50 μm or more, 0.55 μm or more, or 0.60 μm or more. By including large crystal grains G2 in the second nickel plating layer 32, the difference in size between the crystal grains G1 of the first nickel plating layer 31 and the crystal grains G2 of the second nickel plating layer 32 can be increased. By combining two nickel plating layers with different crystal grain sizes, impacts due to contact with other components and stresses due to deformation can be more easily dispersed. Therefore, cracks can be sufficiently prevented from progressing inside the conductive substrate 20.

[0033] The length H of the crystal grain G1 may be 0.10 to 0.60 μm. The length H of the crystal grain G2 may be 0.30 to 1.0 μm, or 0.40 to 0.90 μm. The length W of the crystal grain G1 may be 0.10 to 0.30 μm. The length W of the crystal grain G2 may be 0.15 to 0.60 μm.

[0034] The average value R2 of the ratio (H / W) of the length H to the length W of the crystal grains G2 may be greater than the average value R1 of the ratio (H / W) of the length H to the length W of the crystal grains G1. This allows the hardness to be sufficiently increased while sufficiently suppressing the growth of cracks occurring in the conductive substrate 20. The average value R1 may be 1.0 to 2.0, or 1.2 to 1.8. The average value R2 may be 1.5 to 3.0, or 1.8 to 2.5. The average values ​​R1 and R2 can also be calculated using the length H and length W used to calculate the average particle sizes A1 and A2.

[0035] The first nickel plating layer 31 may be a roughened nickel plating film. The second nickel plating layer 32 may be a matte nickel plating film. The gold plating layer 33 may be an electrolytic gold plating film or an electroless gold plating film. The plating film 30 may have another plating layer on the gold plating layer 33.

[0036] The component of the connector of the present disclosure is not limited to the contact 10. The component of the connector of the present disclosure may be, for example, the shell 12 shown in FIG. 5 . The flange 13, which secures the shell 12 to another component, may also be a component of the connector of the present disclosure. In this case, the shell 12 and the flange 13 may include a conductive base material and a plating film covering the conductive base material. A cross section of the shell 12 and the flange 13 as shown in FIG. 5 is obtained along a first direction perpendicular to the surface of the conductive base material. Observing this cross section with an SEM reveals the cross-sectional structure shown in FIG. 2 and the crystal grains G1 and G2 shown in FIGS. 3 and 4 . In a modified example, the flange 13 may be made of an insulating material such as resin. In this case, only the shell 12 is conductive, and has the cross-sectional structure shown in FIG. 2 and the crystal grains G1 and G2 shown in FIGS. 3 and 4 . The flange 13, which is made of an insulating material, does not qualify as a component of the connector of the present disclosure.

[0037] The hardness measured on the surface of some materials (contacts 10, shell 12, flange 13) of the connector of the present disclosure may be 3.0 HM or more, 3.5 HM or more, or 4.0 HM or more. In the case of a connector that is repeatedly connected and disconnected, friction may cause wear to the surface of some materials of the connector. By having high hardness in the components that may experience such friction, wear resistance can be sufficiently increased. The hardness in the present disclosure is measured by the nanoindentation method. Specifically, the value is measured under the conditions described in the examples.

[0038] An example of a method for manufacturing a connector component will be described. First, a conductive substrate is obtained by a known method, such as pressing, cutting, casting, and forging. Next, the conductive substrate is surface-treated to form a plating film 30. The surface treatment may include pre-treating the surface of the conductive substrate, forming a first nickel plating layer 31, forming a second nickel plating layer 32, and forming a gold plating layer 33.

[0039] The pretreatment may include at least one of degreasing, pickling, and acid activation of the conductive substrate (substrate to be plated). Examples of degreasing include alkaline degreasing and electrolytic degreasing. Subsequently, electrolytic plating is performed using a roughened nickel plating bath to form the first nickel plating layer 31. The roughened nickel plating bath may contain nickel(II) sulfamate, nickel(II) chloride, boric acid, and additives. On the other hand, the roughened nickel plating bath may not contain a brightener. An example of such a roughened nickel plating solution is the "Roughened Nickel Plating Solution" (product name) sold by JX Metals Trading Co., Ltd.

[0040] The thickness T1 of the first nickel plating layer 31 and the size of the crystal grains G1 can be adjusted by changing the current density, the current application time, and the plating bath temperature. For example, the crystal grains G1 can be made smaller by increasing the current density or decreasing the plating bath temperature. Furthermore, the thickness T1 can be increased by increasing the current application time.

[0041] Next, electrolytic plating is performed using a nickel sulfamate plating bath to form a second nickel plating layer 32 on the first nickel plating layer 31. The nickel sulfamate plating bath may contain nickel(II) sulfamate, nickel(II) chloride, and boric acid. However, a nickel sulfamate plating bath with a lower nickel ion content than the roughened nickel plating bath is used. This allows the formation of a second nickel plating layer 32 composed of crystal grains G2 having a grain size larger than that of the crystal grains G1. An example of such a nickel sulfamate plating solution is "Nickel Sulfamate Plating Solution" (product name) sold by JX Metals Trading Co., Ltd.

[0042] The thickness T2 of the second nickel plating layer 32 and the size of the crystal grains G2 can be adjusted by changing the current density, the current application time, and the plating bath temperature. For example, the crystal grains G2 can be made larger by lowering the current density or increasing the plating bath temperature. Furthermore, the thickness T2 can be increased by extending the current application time.

[0043] Next, electrolytic plating is performed using an electrolytic gold plating bath to form a gold plating layer 33 on the second nickel plating layer 32. The electrolytic gold plating bath may contain potassium gold cyanide, potassium cyanide, a brightener, etc. Such an electrolytic gold plating bath may be a commercially available product.

[0044] The contacts 10, shell 12, and flange 13, which are components of a connector, may be manufactured through this series of steps. However, the manufacturing method for the components of a connector is not limited to the above-described method. Components and plated products of electronic components other than connectors can also be manufactured in the same manner as the components of a connector.

[0045] An elongated plug connector 60, which is an example of a connector according to the present disclosure and is shown in Figures 6, 7(A) and (B), 8, and 9(A) and (B), is electrically connected to an electric cable 90. As shown in Figures 6, 7(A) and (B), and 8, the plug connector 60 includes a shell 61 (plug shell), a housing 62 (plug housing), and a plurality of contacts 63 (plug contacts). The plurality of contacts 63 includes a plurality of first contacts 63A and a plurality of second contacts 63B.

[0046] The housing 62 is made of an insulating material containing resin, and holds the multiple contacts 63 while providing insulation between the shell 61 and the contacts 63. The shell 61 is elastic and conductive. The shell 61 includes a first shell 61A that covers the upper part of the housing 62, and a second shell 61B that is connected to the first shell 61A and covers the lower part of the housing 62.

[0047] As shown in FIG. 7A, the upper wall 61a of the first shell 61A covers the tip end of the electric cable 90 and also covers the upper surface of the housing 62. Two openings 61d are provided in the upper wall 61a. The openings 61d are provided at positions overlapping with the electric cable 90 in the Y-axis direction. A protrusion 62d of the housing 62 fits into the openings 61d. The openings 61d and the protrusions 62d of the housing 62 are fixedly attached to each other. This integrates the housing 62 and the first shell 61A and restricts movement of the housing 62 relative to the first shell 61A.

[0048] 7B and 8 is provided below the housing 62. A side wall 61f of the second shell 61B is in contact with a side wall 61b of the first shell 61A, so that the entire shell 61 has the same potential.

[0049] 9A and 9B, each contact 63 includes a connecting portion 63a, a linking portion 63b, and a contact portion 63c. The first contact 63A and the second contact 63B have partially different shapes and are attached to the plug connector 60 at different positions.

[0050] As shown in FIG. 9B, the connecting portion 63a of the first contact 63A extends inside the housing 62 along the inner conductor 91 at the tip end of the electric cable 90, and the exposed inner conductor 91 is connected with solder M. The linking portion 63b of the first contact 63A links the connecting portion 63a and the contact portion 63c. The contact portion 63c of the first contact 63A extends along the tip end 62b of the housing 62 and is exposed on a side surface 62g of the tip end 62b that faces the electric cable 90. The contact portion 63c comes into contact with the first contact 83A (FIG. 10) of the receptacle connector 80 when the receptacle connector 80 and the plug connector 60 are mated. The contact portion 63c has a recess 63d formed therein to ensure reliable contact with the first contact 83A.

[0051] 9(B), the central portion of the coupling portion 63b is a straight portion 63e extending horizontally, and the end portion is a descending portion 63f bent downward (in the direction in which the protrusion P protrudes). As a result, the contact portion 63c and the connecting portion 63a are bent so as to be positioned below the central portion of the coupling portion 63b, i.e., closer to the circuit board 70 (FIG. 10), when mated with the mating connector, receptacle connector 80. In addition, the upper surface of the straight portion 63e (the surface closer to the upper wall portion 61a of the shell 61) is at approximately the same height as the lower surface of the upper wall portion 61a (the surface facing the electric cable 90).

[0052] As shown in FIG. 9A, the connecting portion 63a of the second contact 63B extends along the inner conductor 91 at the tip of the electric cable 90 inside the housing 62, and the exposed inner conductor 91 is connected with solder M. The linking portion 63b of the second contact 63B links the connecting portion 63a and the contact portion 63c. The contact portion 63c of the second contact 63B extends along the tip portion 62b of the housing 62, and its upper portion is exposed on a side surface 62f that is the side surface of the tip portion 62b opposite to the side surface facing the electric cable 90. The contact portion 63c comes into contact with the second contact 83B (FIG. 10) of the receptacle connector 80 when the receptacle connector 80 and the plug connector 60 are mated. The contact portion 63c has a recess 63d formed therein to ensure reliable contact with the second contact 83B.

[0053] 9(A), the central portion of the coupling portion 63b is a straight portion 63e extending horizontally (in the XY direction), and the end portion is a descending portion 63f bent downward (in the direction in which the convex portion P protrudes). As a result, the contact portion 63c and the connecting portion 63a are bent so as to be positioned below the central portion of the coupling portion 63b, i.e., closer to the circuit board 70, when mated with the mating connector, receptacle connector 80. In addition, the upper surface of the straight portion 63e (the surface closer to the upper wall portion 61a of the shell 61) is at approximately the same height as the lower surface of the upper wall portion 61a (the surface facing the electric cable 90).

[0054] 7A and 7B, the first contacts 63A and the second contacts 63B are arranged alternately along the Y-axis direction. The first contacts 63A and the second contacts 63B are also arranged in a line along the Y-axis direction.

[0055] 6 and 9(A) and (B), in the plug connector 60, the housing 62 covering the periphery of the contacts 63 is exposed at an exposed portion 65 formed by an opening 61d of the shell 61. In addition, the connection between the shell 61 and the housing 62 is strengthened by fixing a protrusion 62d of the housing 62 to the inner surface of the opening 61d.

[0056] Among the components constituting the plug connector 60, at least one of the plurality of contacts 63 and / or the shell 61 may be a part of the connector of the present disclosure, which includes a conductive substrate and a plating film covering at least a portion of the conductive substrate. That is, at least one of the plurality of contacts 63 and / or the shell 61 may have a first nickel plating layer 31 closer to the conductive substrate, a second nickel plating layer 32 adjacent to the first nickel plating layer 31, and a gold plating layer 33 adjacent to the second nickel plating layer 32, similar to the contact 10 of FIG. 1. The first nickel plating layer 31 and the second nickel plating layer 32 are composed of the above-mentioned crystal grains G1 and crystal grains G2, respectively.

[0057] 10, a receptacle connector 80, which is another example of a connector of the present disclosure, may be a mating connector of the plug connector 60. The receptacle connector 80 is an elongated connector whose main body extends along the second direction (Y-axis direction), and is attached to the main surface 70s of the circuit board 70.

[0058] 10 and 11(A) and (B), the receptacle connector 80 includes a shell 81, a housing 82 facing the circuit board 70, and a plurality of contacts 83. The plurality of contacts 83 includes a plurality of first contacts 83A and a plurality of second contacts 83B.

[0059] The housing 82 is made of an insulating material containing resin and holds a plurality of contacts 83 arranged in parallel in the Y-axis direction. The housing 82 is also interposed between the shell 81 and the contacts 83 to insulate them from each other. The housing 82 holds the contacts 83 while covered by the shell 81.

[0060] As shown in Fig. 10, the housing 82 has a recessed groove 82c extending in the Y-axis direction so as to open its upper surface. The groove 82c is a space for accommodating the plug connector 60. The groove 82c accommodates the protrusion P (see Fig. 7B, Fig. 9A and Fig. 9B) of the plug connector 60. One ends of the first contacts 83A and the second contacts 83B are exposed inside the groove 82c.

[0061] 11A and 11B, a portion of a top surface 82f of the housing 82 is covered by the shell 81, and the remaining portion of the top surface 82f and the bottom surface 82g are exposed and not covered by the shell 81. The shell 81 is elastic and conductive. For example, as shown in FIGS. 11A and 11B and 12A and 12B, the shell 81 includes a top surface portion 81a, a pair of side wall portions 81b and 81c extending along the X-axis direction, and a pair of side wall portions 81d extending along the Y-axis direction so as to generally cover the housing 82.

[0062] The top surface portion 81a extends along the XY plane so as to cover the top surface 82f of the housing 82. Near the center along the longitudinal direction of the top surface portion 81a, the top surface portion 81a is formed to cover the top surfaces of the first contacts 83A and the second contacts 83B near the other ends of the top surfaces of the top surface 82f of the housing 82, with the grooves 82c sandwiched between them, so that the protrusions P of the plug connector 60 can be inserted from above into the grooves 82c of the housing 82.

[0063] As shown in Fig. 11A, the side walls 81b and 81c face each other in the X-axis direction and extend along the Y-axis direction. The side walls 81b and 81c are provided with a plurality of protrusions 81y that protrude outward (in a direction away from the housing 82) in the horizontal direction (XY direction). The protrusions 81y can be used to fix the shell 81 to the main surface 70s of the circuit board 70. That is, the protrusions 81y can be fixed to the main surface 70s shown in Fig. 10 by solder or the like.

[0064] The contacts 83 (first contact 83A and second contact 83B) are elastic and conductive. The first contact 83A and the second contact 83B may have the same shape. However, as shown in FIG. 11B, the first contact 83A and the second contact 83B are attached to the receptacle connector 80 at different positions.

[0065] Among the components constituting the receptacle connector 80, at least one of the plurality of contacts 83 and / or the shell 81 may be a part of a connector including a conductive base material and a plating film covering at least a portion of the conductive base material. That is, at least one of the plurality of contacts 83 and / or the shell 81 has a first nickel plating layer 31 closer to the conductive base material, a second nickel plating layer 32 adjacent to the first nickel plating layer 31, and a gold plating layer 33 adjacent to the second nickel plating layer 32, similar to the contact 10 in FIG. 1. The first nickel plating layer 31 and the second nickel plating layer 32 are composed of the above-mentioned crystal grains G1 and crystal grains G2, respectively.

[0066] When the plug connector 60 and the receptacle connector 80 are mated, as shown in Figures 12A and 12B, the protrusion P of the plug connector 60 is accommodated in the groove 82c of the receptacle connector 80. As shown in Figure 12A, the connection portion 83a of the second contact 83B of the receptacle connector 80 is disposed on the main surface 70s of the circuit board 70 and connected to the conductive path of the circuit board 70 by, for example, solder. As shown in Figure 12B, the connection portion 83a of the first contact 83A of the receptacle connector 80 is also disposed on the main surface 70s of the circuit board 70 and connected to the conductive path of the circuit board 70 by, for example, solder.

[0067] In the mated state, as shown in FIG. 12B, the contact portion 63c of the first contact 63A of the plug connector 60 contacts the contact portion 83c of the first contact 83A of the receptacle connector 80, thereby electrically connecting the first contacts 63A and 83A to each other. Also, as shown in FIG. 12A, the contact portion 63c of the second contact 63B of the plug connector 60 contacts the contact portion 83c of the second contact 83B of the receptacle connector 80, thereby electrically connecting the second contacts 63B and 83B to each other. In this mated state, the plug connector 60 and the receptacle connector 80 may, for example, form part of a signal circuit by the contacts 63 and 83. The contacts 63 and 83 may each have a plating film having a first nickel plating layer 31 near the conductive substrate and a second nickel plating layer 32 adjacent to the first nickel plating layer 31. This reduces cracks that occur in the conductive base materials of the contacts 63 and 83 due to impacts or stresses caused by deformation caused by contact.

[0068] 13 shows another example of a connector according to the present disclosure, connector 200, which may be a so-called D-sub connector that is attached to a circuit board. Connector 200 has a D-shaped shell 211, a plurality of pins (terminals) 213, an insert 212 that insulates adjacent pins 213 from each other, and mounting ears 230 for attaching connector 200 to a housing. At least one selected from the group consisting of shell 211 and pins 213 is a component of the connector according to the present disclosure, which comprises a conductive base material and a plating film that covers at least a portion of the conductive base material.

[0069] 1, at least one selected from the group consisting of the shell 211 and the pin 213 has a first nickel plating layer 31 closer to the conductive substrate, a second nickel plating layer 32 adjacent to the first nickel plating layer 31, and a gold plating layer 33 adjacent to the second nickel plating layer 32. The first nickel plating layer 31 and the second nickel plating layer 32 are composed of the above-mentioned crystal grains G1 and crystal grains G2, respectively.

[0070] Although some examples of connector materials, manufacturing methods thereof, and connectors have been described above, the present invention is not limited to these examples. For example, the electronic component is not limited to a connector. The plating film 30 does not necessarily have to include the gold plating layer 33. Furthermore, the plating film 30 may include another plating layer instead of the gold plating layer 33. Examples of such plating layers include a tin plating layer, a tin alloy plating layer, an Ag plating layer, a lead alloy plating layer, a Pd plating layer, and a Pd alloy plating layer.

[0071] Although an example of an electrical connector has been given, the connector is not limited to an electrical connector and may be, for example, an optical connector.

[0072] This disclosure includes the following contents [1] to

[12] . [1] A component of an electronic component comprising a conductive base material and a plating film that covers at least a portion of the conductive base material, the plating film has a first nickel plating layer near the conductive base material and a second nickel plating layer adjacent to the first nickel plating layer, When a cross section taken along a first direction perpendicular to the surface of the conductive base material coated with the plating film is viewed, A material for an electronic component, wherein the average grain size A1 of the crystal grains G1 constituting the first nickel plating layer is smaller than the average grain size A2 of the crystal grains G2 constituting the second nickel plating layer. [2] Among the crystal grains G1 constituting the first nickel plating layer, the grain size of the crystal grains G1 in contact with the conductive base material is less than 0.50 μm; The part material of the electronic component according to [1], wherein the crystal grains G2 include those having a grain size of 0.50 μm or more. [3] A part material for an electronic component according to [1] or [2], wherein the average particle size A1 is less than 0.40 μm, and the average particle size A2 is 0.40 μm or more. [4] A component of an electronic component comprising a conductive base material and a plating film that covers at least a portion of the conductive base material, the plating film has a first nickel plating layer near the conductive base material and a second nickel plating layer adjacent to the first nickel plating layer, When a cross section taken along a first direction perpendicular to the surface of the conductive base material coated with the plating film is viewed, Among the crystal grains G1 constituting the first nickel plating layer, the grain size of the crystal grains G1 in contact with the conductive base material is all less than 0.50 μm, The second nickel plating layer is a part of an electronic component, and the crystal grains G2 constituting the second nickel plating layer include those having a grain size of 0.50 μm or more. [5] A part of an electronic component described in any one of [1] to [4], wherein, in the cross section, when a direction perpendicular to the first direction is defined as a second direction, the average value R2 of the ratio of the length of the crystal grain G2 along the second direction to the length of the crystal grain G2 along the first direction is larger than the average value R1 of the ratio of the length of the crystal grain G1 along the second direction to the length of the crystal grain G1 along the first direction. [6] A part of an electronic component according to [5], wherein the average value R1 is 1.0 or more and the average value R2 is 2.0 or more. [7] The first nickel plating layer is composed of a roughened nickel plating film, The part of the electronic component according to any one of [1] to [6], wherein the second nickel plating layer is made of a matte nickel plating film. [8] The total thickness of the first nickel plating layer and the second nickel plating layer is 4.0 μm or less, The part of an electronic component according to any one of [1] to [7], wherein the second nickel plating layer has a thickness greater than that of the first nickel plating layer. [9] A part material for an electronic component according to any one of [1] to [8], wherein the hardness measured on the surface of the plating film is 3.0 HM or more.

[10] A part of an electronic component according to any one of [1] to [9], wherein the plating film comprises a gold plating layer adjacent to the second nickel plating layer.

[11] An electronic component comprising a component material for the electronic component according to any one of [1] to

[10] above.

[12] A method for manufacturing a component of an electronic component including a conductive base material and a plating film that covers at least a portion of the conductive base material, comprising: forming a roughened nickel plating film so as to cover at least a portion of the surface of the conductive substrate; forming a matte nickel plating film so as to cover at least a portion of the surface of the roughened nickel plating film.

[0073] The electronic component material described in [1] above has a first nickel plating layer near the conductive substrate, the first nickel plating layer being composed of crystal grains G1 having an average grain size smaller than that of the crystal grains G2 constituting the second nickel plating layer. Therefore, when the electronic component material is subjected to an external impact or deformed, the conductive substrate is less likely to be scratched. Furthermore, the crystal grains G2 constituting the second nickel plating layer have an average grain size A2 larger than that of the crystal grains G1. Thus, the first nickel plating layer and the second nickel plating layer are both composed of crystal grains with different average grain sizes, which facilitates the dispersion of impacts and stress. It is believed that these factors can reduce cracks occurring in the conductive substrate. However, the electronic component material described above may also reduce cracks occurring in the conductive substrate by a different mechanism.

[0074] Among the crystal grains G1 constituting the first nickel plating layer of the material of the electronic component described in [2] above, the grain size of the crystal grains G1 in contact with the conductive base material is sufficiently small. Therefore, when the material of the electronic component is subjected to an external impact or deformed, the conductive base material is less likely to be damaged. Furthermore, since such a first nickel plating layer is combined with the second nickel plating layer containing crystal grains G2 with a larger grain size, impact and stress are more easily dispersed. It is believed that these factors can sufficiently suppress the propagation of cracks inside the conductive base material.

[0075] In the electronic component material [3], the crystal grains G1 constituting the first nickel plating layer have a sufficiently small average grain size A1, which is thought to be sufficient to prevent cracks from propagating inside the conductive base material.

[0076] In the electronic component material described in [4] above, among the crystal grains G1 constituting the first nickel plating layer closer to the conductive substrate, the crystal grains G1 in contact with the conductive substrate have a sufficiently small grain size. Therefore, when the electronic component material is subjected to an external impact or deformed, the conductive substrate is less likely to be damaged. Furthermore, since the electronic component material described above combines such a first nickel plating layer with a second nickel plating layer containing crystal grains G2 with a large grain size, impact and stress are more easily dispersed. It is believed that these factors can reduce cracks occurring in the conductive substrate. However, the electronic component material described above may also reduce cracks occurring in the conductive substrate by a different mechanism.

[0077] The part of the electronic component described in [5] above makes the conductive substrate less susceptible to damage when the part of the electronic component is subjected to an external impact or when the part of the electronic component is deformed. Therefore, it is believed that the part of the electronic component described above can reduce cracks that occur in the conductive substrate.

[0078] The material of the electronic component described in [6] above has a sufficiently high hardness because the average values ​​R1 and R2 are equal to or greater than the predetermined values, which makes it possible to prevent scratches from occurring on the surface of the material of the electronic component.

[0079] The roughened nickel plating film constituting the first nickel plating layer of the part of the electronic component [7] above tends to be softer and have smaller crystal grains than the matte nickel plating film constituting the second nickel plating layer. This can reduce cracks that occur in the conductive substrate. It can also increase the hardness of the surface of the part of the electronic component.

[0080] In the part of the electronic component described in [8] above, the sum of the thicknesses of the first nickel plating layer and the second nickel plating layer is equal to or less than a predetermined value, and therefore the tensile stress on the surface of the plating film is reduced when the part is deformed, thereby further suppressing the progression of cracks.

[0081] The material of the electronic component described in [9] above has a sufficiently high hardness, which can prevent scratches from occurring on the surface of the material of the electronic component.

[0082] Some materials for the electronic components described in

[10] above are easy to solder and have excellent electrical conductivity and corrosion resistance.

[0083] The electronic component of the above item

[11] includes a member capable of reducing cracks that occur in the conductive substrate, and such an electronic component has excellent connection reliability.

[0084] In the electronic component obtained by the manufacturing method

[12] above, at least a portion of the conductive substrate is coated with a roughened nickel plating film that is softer and has smaller crystal grains than a matte nickel plating film. Therefore, when the electronic component is subjected to an external impact or deformed, the conductive substrate is less likely to be scratched. Furthermore, at least a portion of the surface of the roughened nickel plating film is coated with a matte nickel plating film that has larger crystal grains than the roughened nickel plating film. Therefore, when the electronic component is subjected to an external impact or deformed, the impact and stress are more easily dispersed. It is believed that these factors can reduce cracks in the conductive substrate. However, the connector component may reduce cracks in the conductive substrate using a different mechanism.

[0085] The present disclosure also includes a plated product comprising a conductive substrate and a plating film covering at least a portion of the conductive substrate. The plated product can be widely used as a conductive material that conducts electricity, and is therefore not limited to use as a part of a connector, but can also be used as an electronic component that constitutes an electric circuit or an electronic circuit. The plating film 30 in the plated product may have a first nickel plating layer 31, a second nickel plating layer 32, and a gold plating layer 33. That is, the present disclosure includes the following contents

[13] to

[15] .

[0086]

[13] A plated product comprising a conductive substrate and a plating film that covers at least a portion of the conductive substrate, the plating film has a first nickel plating layer near the conductive base material and a second nickel plating layer adjacent to the first nickel plating layer, When a cross section taken along a first direction perpendicular to the surface of the conductive base material coated with the plating film is viewed, A plated product, wherein the average grain size A1 of the crystal grains G1 constituting the first nickel plating layer is smaller than the average grain size A2 of the crystal grains G2 constituting the second nickel plating layer.

[14] A plated product comprising a conductive substrate and a plating film that covers at least a portion of the conductive substrate, the plating film has a first nickel plating layer near the conductive base material and a second nickel plating layer adjacent to the first nickel plating layer, When a cross section taken along a first direction perpendicular to the surface of the conductive base material coated with the plating film is viewed, Among the crystal grains G1 constituting the first nickel plating layer, the grain size of the crystal grains G1 in contact with the conductive base material is all less than 0.50 μm, A plated product, wherein the crystal grains G2 constituting the second nickel plating layer include those having a grain size of 0.50 μm or more.

[15] A method for manufacturing a plated product comprising a conductive base material and a plating film covering at least a portion of the conductive base material, forming a roughened nickel plating film so as to cover at least a portion of the surface of the conductive substrate; forming a matte nickel plating film so as to cover at least a portion of the surface of the roughened nickel plating film.

[0087] The plated products

[13] and

[14] above have a first nickel plating layer near the conductive substrate, which is composed of crystal grains G1 having an average diameter smaller than that of the crystal grains G2 constituting the second nickel plating layer. Therefore, when an external force is applied to the plated product or when the plated product is deformed, the conductive substrate is less likely to be scratched. Therefore, it is believed that the plated products can reduce cracks that occur in the conductive substrate.

[0088] According to the manufacturing method

[15] above, it is possible to manufacture a plated product that can reduce cracks that occur in the conductive substrate. [Example]

[0089] The present disclosure will be described in more detail below with reference to examples and comparative examples, although the present invention is not limited to the following examples.

[0090] Example 1 <Formation of plating film> The following steps (1) to (5) were carried out in this order to form a plating film on the surface of a flat plate-shaped conductive substrate made of brass. (1) Alkaline degreasing The conductive substrate was immersed in a commercially available alkaline degreasing agent whose temperature was adjusted to 50°C to remove oil adhering to the surface of the conductive substrate. (2) Electrolytic degreasing The conductive substrate was immersed in a commercially available electrolytic degreasing agent whose temperature was adjusted to 50°C, and while immersed, electricity was passed through the conductive substrate, and the surface of the conductive substrate was cleaned with the generated hydrogen gas. The current density was 5 A / dm 2 It was decided.

[0091] (3) Acid activity The conductive substrate was immersed in a commercially available acid-activating chemical (at room temperature) to remove the oxide film and impurities from the surface of the conductive substrate.

[0092] (4) First electrolytic nickel plating process A roughened nickel plating film was formed on the surface of the conductive substrate using a "roughened nickel plating solution" (product name) sold by JX Metals Trading Co., Ltd. The main components of this "roughened nickel plating solution" are shown in Table 1. The conductive substrate was placed in a plating bath consisting of this roughened nickel plating solution (50°C). Then, a 10 A / dm 2 A roughened nickel plating film was formed on the surface of the conductive substrate by passing a current through the solution for a predetermined time at a current density of 130 g / L. The nickel content in the roughened nickel plating solution was about 130 g / L.

[0093] [Table 1]

[0094] (5) Second electrolytic nickel plating process A matte plating film was formed on the surface of the roughened nickel plating film using "Sulfamate Nickel Plating Solution" (trade name) sold by JX Metals Trading Co., Ltd. The components of this "Sulfamate Nickel Plating Solution" are shown in Table 2. The conductive substrate on which the roughened nickel plating film had been formed was placed in a plating bath consisting of this sulfamate nickel plating solution (50°C). Next, a current of 5 A / dm was applied from an external DC power source. 2 A matte nickel plating film was formed on the surface of the roughened nickel plating film of the conductive substrate by passing a predetermined current at a current density of 1000 kJ / L. The nickel content in the nickel sulfamate plating solution was approximately 84 g / L.

[0095] [Table 2]

[0096] In this way, a plated product was obtained having a flat conductive substrate and a plating film covering the surface of the substrate. The plating film had a roughened nickel plating film as a first nickel plating layer closer to the conductive substrate and a matte nickel plating film as a second nickel plating layer adjacent to the first nickel plating layer.

[0097] <Hardness measurement> The surface hardness of the plating film was measured by nanoindentation. The measuring device used was an ENT100A (trade name) manufactured by Elionix Co., Ltd. A Berkovich-type synthetic diamond indenter was used for the measurement, and the measurement conditions were a maximum load of 1,000 mN, a loading speed of 100 mN / s, and a maximum load holding time of 5 seconds. Ten measurement points were measured, and the average value was calculated by taking the arithmetic mean of the central five points. The average values ​​obtained are shown in Table 5.

[0098] <Observation of the plating film surface> As shown in FIG. 14, a plated article 50 was bent along a center line CL to form a bent portion. FIG. 15 shows a plated article with a bent portion formed. After forming the bent portion, the surface of the mountain fold side of the bent portion of the plated article (the area surrounded by the dotted line in FIG. 15) was observed using a field emission scanning electron microscope (FE-SEM, JEOL Ltd., product name: JSM-7800F). In addition, the plated article was cut along the cutting line CT in FIG. 14 using an ion milling device, and the cross section of the plated article was observed using the same field emission scanning electron microscope. This cross section is along a direction (first direction) perpendicular to the surface coated with the plating film on the conductive base material.

[0099] 16(A) and (B) are SEM photographs of the surface of the bent portion. As shown in these SEM photographs, it was confirmed that many small cracks had occurred on the surface of the bent portion.

[0100] <Observation of the cross section of the plating film> Figures 17(A) and 17(B) show SEM photographs of the cross section of the bent portion. The depression in the center of Figure 17(B) is a crack. The electron microscope photograph shown in Figure 17(B) confirmed that the plating film was composed of a first nickel plating layer (roughened nickel plating film) and a second nickel plating layer (matte nickel plating film). It was also confirmed that the thickness of the first nickel plating layer (roughened nickel plating film) was approximately 0.5 µm, and the thickness of the second nickel plating layer (matte nickel plating film) was approximately 1.5 µm. The total thickness of the first nickel plating layer and the second nickel plating layer, i.e., the thickness of the plating film, was approximately 2.0 µm.

[0101] Figure 18 is an EBSD map of the SEM image of (B) in Figure 17. As shown in Figure 18, the depth DP of the cracks that occurred in the conductive substrate was measured based on the interface (coated surface) between the plating film and the conductive substrate. The results are shown in Table 5.

[0102] <Analysis of plating film structure> The sizes of the crystal grains G1 constituting the first nickel plating layer 31 and the crystal grains G2 constituting the second nickel plating layer 32 were measured using EBSD maps photographed in the same manner as in Fig. 18. Specifically, as shown in Fig. 19(A) and (B), 10 crystal grains G1 (Nos. 1 to 10) were randomly selected from the crystal grains G1 in contact with the conductive base material, and the size of each crystal grain G1 was measured. In addition, as shown in Fig. 20(A) and (B), 10 crystal grains G2 (Nos. 1 to 10) were randomly selected from the crystal grains G2 exposed on the surface of the second nickel plating layer 32, and the size of each crystal grain G2 was measured.

[0103] The size of each crystal grain G1 and each crystal grain G2 was measured by measuring the length H along the y direction (first direction, see Figures 2 and 4) perpendicular to the surface coated with the plating film on the conductive base material, and the length W along the x direction (second direction, see Figure 4) perpendicular to the y direction. The lengths H and W of each crystal grain G1 were measured by regarding a region having the same crystal orientation as one crystal grain G1 as shown in Figure 21, and calculated by comparing them with the length of the scale bar. The lengths H and W of each crystal grain G2 were also measured by regarding a region having the same crystal orientation as one crystal grain G2 as shown in Figure 22, and calculated by comparing them with the length of the scale bar.

[0104] The grain size of each crystal grain was calculated from the length H and length W of each crystal grain G1 and G2 using the formula (H + W) / 2. The arithmetic mean of the grain sizes of each crystal grain G1 was defined as the average grain size A1, and the arithmetic mean of the grain sizes of each crystal grain G2 was defined as the average grain size A2. In addition, the aspect ratio (H / W) was calculated from the length H and length W of each crystal grain G1 and G2, and the average values ​​R1 and R2 of the crystal grains G1 and G2 were calculated. These results are summarized in Tables 3 and 4.

[0105] [Table 3]

[0106] [Table 4]

[0107] As shown in Table 3, the grain sizes of the crystal grains G1 of Nos. 1 to 10 contained in the first nickel plating layer 31 were all less than 0.50 μm. All of the crystal grains G1 of Nos. 1 to 10 were in contact with the conductive substrate. On the other hand, as shown in Table 4, among the crystal grains G2 contained in the second nickel plating layer 32, some of the crystal grains G2 had grain sizes of 0.50 μm or more.

[0108] (Comparative Example 1) In the <Formation of plating film>, "(4) First electrolytic nickel plating process" was not carried out, and "(5) Second electrolytic nickel plating process" was carried out at 5A / dm 2A plated product having a flat conductive substrate and a plating film covering the surface thereof was obtained in the same manner as in Example 1, except that the time for which current was passed at a current density of 1000 kJ / min was longer than that in Example 1. The plating film had only a matte nickel plating film.

[0109] The plated product of Comparative Example 1 was subjected to <hardness measurement>, <surface observation of the plating film>, and <cross-section observation of the plating film> in the same manner as in Example 1. The hardness measurement results are shown in Table 5.

[0110] When the surface of the plating film was observed using an SEM, it was confirmed that larger cracks had occurred in the plated product of Comparative Example 1 than in Example 1, as shown in the SEM photographs of Figures 23(A) and (B).

[0111] FIG. 24(A) is an SEM photograph of the cross section at the bent portion. The depression in the center of FIG. 24(B) is a crack. In the SEM photograph shown in FIG. 24(B), the plating film appears to have a two-layer structure, but this is due to the unevenness that occurred when the cross section was polished. In reality, the plating film of Comparative Example 1 had a single-layer structure. The thickness of the plating film was approximately 2.0 μm, which was equivalent to that of Example 1.

[0112] Figure 25 is an EBSD map of the SEM image of Figure 24(B). As is clear from this EBSD map, some of the crystal grains in contact with the conductive substrate had a grain size exceeding 1 μm. As shown in Figure 25, the depth DP of the cracks occurring in the conductive substrate was measured based on the interface (coated surface) between the plating film and the conductive substrate. The results are shown in Table 5.

[0113] (Comparative Example 2) A plated product having a flat conductive substrate and a plating film covering its surface was obtained in the same manner as in Example 1, except that the order of the "(4) first electrolytic nickel plating step" and the "(5) second electrolytic nickel plating step" in <Formation of plating film> was reversed. The plating film had a matte nickel plating film as a first nickel plating layer closer to the conductive substrate, and a roughened nickel plating film as a second nickel plating layer adjacent to the first nickel plating layer.

[0114] The plated product of Comparative Example 2 was subjected to <hardness measurement>, <surface observation of the plating film>, and <cross-section observation of the plating film> in the same manner as in Example 1. The hardness measurement results are shown in Table 5.

[0115] When the surface of the plating film was observed using an SEM, it was confirmed that larger cracks had occurred in the plated product of Comparative Example 2 than in Example 1, as shown in the SEM photographs of Figures 26(A) and (B).

[0116] When the cross section of the bent portion was observed with a scanning electron microscope, the thickness of the first nickel plating layer (matte nickel plating film) closer to the conductive substrate was approximately 0.5 μm, and the thickness of the second nickel plating layer (roughened nickel plating film) was approximately 1.5 μm. The thickness of the plating film was approximately 2.0 μm. In the plated product of Comparative Example 2, the crystal grains G1 constituting the first nickel plating layer closer to the conductive substrate were larger than the crystal grains G2 constituting the second nickel plating layer.

[0117] (Reference example 1) A plated product having a flat conductive substrate and a plating film covering its surface was obtained in the same manner as in Example 1, except that instead of the "(4) first electrolytic nickel plating step" in <Plating Film Formation>, an electrolytic copper plating step using a copper plating bath (with additives) was performed to form an electrolytic copper plating film with a thickness of 1.5 μm, and the current application time in the "(5) second electrolytic nickel plating step" was shortened compared to Example 1 to form a matte nickel plating film with a thickness of 0.5 μm. That is, the plating film of Reference Example 1 had a first plating layer consisting of an electrolytic copper plating film closer to the conductive substrate and a second plating layer consisting of a matte nickel plating film adjacent to the first plating layer. <Hardness Measurement> of the plated product of Reference Example 1 was performed in the same manner as in Example 1. The hardness measurement results are shown in Table 5.

[0118] (Reference example 2) A plated product having a flat conductive substrate and a plating film covering its surface was obtained in the same manner as in Example 1, except that an electrolytic copper plating process using a copper plating bath (without additives) was performed to form a matte copper plating film with a thickness of 2.0 μm instead of the "(4) first electrolytic nickel plating process" and "(5) second electrolytic nickel plating process" in <Formation of plating film>. That is, the plating film of Reference Example 2 was composed of a plating layer made of a matte copper film. <Hardness measurement> of the plated product of Reference Example 2 was performed in the same manner as in Example 1. The hardness measurement results are shown in Table 5.

[0119] [Table 5]

[0120] As shown in Table 5, the plated product of Example 1 was able to reduce cracks that occurred in the conductive substrate. Furthermore, the plated product of Example 1 had the highest hardness. [Explanation of symbols]

[0121] 10...contact, 12, 211...shell, 13...flange, 20...conductive base material, 20a...coating surface, 30...plating film, 31...first nickel plating layer, 32...second nickel plating layer, 33...gold plating layer, 50...plated product, 60...plug connector, 61...shell (plug shell), 61A...first shell, 61B...second shell, 62...housing (plug housing), 63...contact (plug contact), 63A, 83A...first contact, 63B, 83B...second contact, 65...exposed portion, 70...circuit board, 80...receptacle connector, 82...housing, 83...contact, 90...electrical cable, 91...inner conductor, 200...connector, G1, G2...crystal grains.

Claims

1. A component of an electronic component comprising a conductive substrate made of copper or a copper alloy and a plating film covering at least a portion of the conductive substrate, the plating film has a first nickel plating layer near the conductive base material and a second nickel plating layer adjacent to the first nickel plating layer, When a cross section taken along a first direction perpendicular to the surface of the conductive base material coated with the plating film is viewed, A material for an electronic component, wherein the average particle size A1 of the crystal grains G1 constituting the first nickel plating layer is smaller than the average particle size A2 of the crystal grains G2 constituting the second nickel plating layer, and when a direction perpendicular to the first direction is defined as a second direction, the average ratio R2 of the length of the crystal grains G2 along the first direction to the length of the crystal grains G2 along the second direction is larger than the average ratio R1 of the length of the crystal grains G1 along the second direction to the length of the crystal grains G1 along the first direction.

2. Among the crystal grains G1 constituting the first nickel plating layer, the grain size of the crystal grains G1 in contact with the conductive base material is all less than 0.50 μm, 2. The part material of the electronic component according to claim 1, wherein the crystal grains G2 include those having a grain size of 0.50 μm or more.

3. 2. The part material for an electronic component according to claim 1, wherein the average particle size A1 is less than 0.40 μm, and the average particle size A2 is 0.40 μm or more.

4. A part of the electronic component described in claim 1, wherein the average particle size A1 is 0.10 μm or more and less than 0.40 μm.

5. 5. The part of an electronic component according to claim 1, wherein the average value R1 is 1.0 or more and the average value R2 is 1.5 or more.

6. A part of an electronic component described in any one of claims 1 to 4, wherein the average value R1 is 1.0 to 2.0 and the average value R2 is 1.5 to 3.

0.

7. the first nickel plating layer is composed of a roughened nickel plating film, The part of the electronic component according to any one of claims 1 to 4, wherein the second nickel plating layer is composed of a matte nickel plating film.

8. the total thickness of the first nickel plating layer and the second nickel plating layer is 4.0 μm or less; 5. The part of an electronic component according to claim 1, wherein the second nickel plating layer has a thickness greater than that of the first nickel plating layer.

9. 5. The part material of an electronic component according to claim 1, wherein the hardness measured on the surface of the plating film is 3.0 HM or more.

10. The part of the electronic component according to any one of claims 1 to 4, wherein the plating film comprises a gold plating layer adjacent to the second nickel plating layer.

11. An electronic component comprising a component material according to any one of claims 1 to 4.

12. A method for manufacturing a material for an electronic component comprising a conductive substrate made of copper or a copper alloy and a plating film covering at least a portion of the conductive substrate, comprising: forming a roughened nickel plating film so as to cover at least a portion of the surface of the conductive substrate; forming a matte nickel plating film so as to cover at least a portion of the surface of the roughened nickel plating film, the plating film has a first nickel plating layer made of the roughened nickel plating film near the conductive base material, and a second nickel plating layer made of the matte nickel plating film adjacent to the first nickel plating layer, A method for manufacturing a material for an electronic component, wherein, when a cross section is viewed along a first direction perpendicular to the coated surface of the conductive base material by the plating film, an average particle size A1 of crystal grains G1 constituting the first nickel plating layer is smaller than an average particle size A2 of crystal grains G2 constituting the second nickel plating layer, and when a direction perpendicular to the first direction is defined as a second direction, an average ratio R2 of the length of the crystal grains G2 along the first direction to the length of the crystal grains G2 along the second direction is larger than an average ratio R1 of the length of the crystal grains G1 along the first direction to the length of the crystal grains G1 along the second direction.

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