Composite material, terminal and method for manufacturing terminal

Abstract

A composite material for use in the production of a terminal having a welded portion and a terminal fitting portion, the composite material being obtained by forming a metal coating film and a composite coating film on a blank, the metal coating film containing silver and / or tin, the composite coating film comprising a silver layer containing carbon particles, the composite material has a portion where the metal film is exposed and a portion where the composite film is exposed.

Description

Technical Field

[0001] The present invention relates to a composite material for manufacturing a terminal, a terminal, and a method for manufacturing a terminal. Background Art

[0002] Among the terminals of connectors for electronic devices and the like, there are terminals with one end welded to a printed circuit board or the like and the other end connected to an object terminal. For example, one end of a rod-shaped male terminal used in an automobile for relaying a printed circuit board and a wiring harness is called a terminal fitting portion and has a function of fitting with a female terminal, and the other end is called a welding portion and has a function of welding to a substrate.

[0003] In this case, in order to ensure stable electrical contact with the female terminal, the terminal fitting portion is required to have a small contact resistance. In addition, in recent years, with the continuous upgrading of electronic control units (ECUs) and the like, the number of terminals in the connector portion has gradually increased (multi-polarization), and the force required for fitting the male terminal and the female terminal is likely to increase. In this case, in order to make fitting easier, the friction coefficient of the terminal fitting portion is also required to be low. On the other hand, since the welding portion of the terminal is welded to a printed circuit board, good weldability is required.

[0004] Although it is not a terminal for a connector, Patent Document 1 discloses an electronic component for mounting on a printed circuit board, in which a contact formed integrally with an external connection terminal is provided to be exposed on the inner bottom surface of an insulating housing, and a metal plate obtained by performing the following treatment is used as the material for integrally forming the external connection terminal and the contact: a surface plating treatment with a low contact resistance (for example, silver plating) is applied to the contact surface side of the contact, and a surface plating treatment with good weldability (for example, tin plating) is applied to the back side thereof. According to the drawings of this document, one end of the aforementioned external connection terminal is in contact with a fixed contact, and the other end is subjected to a welding treatment.

[0005] Regarding the terminal for a connector, Patent Document 2 discloses a conductive material in which a part of a blank is covered with a thin Sn plating layer and the remaining part is covered with a thick Sn plating layer, and as a base layer for the thin Sn plating layer and the thick Sn plating layer, the conductive material has a base layer formed of a Ni plating layer and a Cu plating layer from the side of the blank. The portion covered with the aforementioned thin Sn plating layer having a low friction coefficient functions as a terminal fitting portion, and the portion covered with the aforementioned thick Sn plating layer having excellent heat resistance and weldability functions as a welding portion.

[0006] In addition, Patent Document 3 discloses a male terminal having a metal as a blank and having a fitting portion for fitting with a female terminal and a welding portion for welding, and a three-layer or four-layer plating with different laminated structures (the surface layer is all Sn plating) is applied to the fitting portion and the welding portion.

[0007] Prior Art Documents

[0008] Patent document

[0009] Patent document 1: Japanese Patent Laid-Open No. 9-298018

[0010] Patent document 2: Japanese Patent Laid-Open No. 2005-307240

[0011] Patent document 3: WO2008 / 072418 Summary of the invention

[0012] Problems to be Solved by the Invention

[0013] For example, there are the following problems in the terminals for printed circuit boards used in automobiles: due to the vibration during driving (while being kept in a high-temperature environment), the contact portion between the male terminal and the female terminal slides with a very small distance of about 50 μm, resulting in easy wear of the outermost layer (microslip wear), and this microslip wear causes an increase in the resistance of the contact portion (impairment of contact reliability). In the terminals for printed circuit boards in automobiles and the like in recent years, due to the miniaturization of the terminals, the thickness of the spring portion becomes thinner, and the spring displacement amount cannot be sufficiently ensured, resulting in a smaller contact load at the contact point between the male terminal and the female terminal. As a result, the contact point is likely to move, and it is difficult to suppress the microslip wear caused by the microslip.

[0014] In the terminal structure disclosed in Patent Document 1 (a terminal with a silver plating applied to the portion connected to the contact), since silver is likely to cause adhesion, there is a problem that microslip wear is likely to occur. Patent Documents 2 and 3 do not consider microslip wear.

[0015] Based on the above, an object of the present invention is to provide a terminal, a manufacturing method thereof, and a composite material that can be used to manufacture the aforementioned terminal, the terminal having: a terminal fitting portion that is not likely to cause microslip wear and has a friction coefficient as low as the same level as the prior art (hereinafter, not being likely to cause microslip wear is also referred to as "excellent microslip wear characteristics"); and a welding portion that has welding properties as excellent as those of the prior art.

[0016] In addition, for the Sn plating used in the terminals disclosed in Patent Documents 1 to 3, in order to prevent the generation of whiskers that can cause a short circuit in the circuit, a heat treatment (reflow soldering) needs to be performed after forming the Sn plating layer, so the manufacturing cost of the terminal becomes high. Moreover, for Patent Document 1, different types of plating are applied to the front and back surfaces of the terminal. Therefore, when performing the first plating on the blank, a mask is required to prevent the opposite surface from being plated (the mask also needs to be removed after plating), and then when plating the opposite surface, the surface of the first plating needs to be masked, which also results in a high manufacturing cost of the terminal.

[0017] Accordingly, an object of the present invention is to provide a terminal that can be manufactured at low cost through a simple manufacturing process and a method for manufacturing the same.

[0018] Solutions for Solving the Problems

[0019] The inventors of the present invention conducted in-depth research to solve the above problems and found that by forming a metal coating containing at least one of silver and tin on the welding part and a composite coating in which carbon particles are dispersed in a silver layer on the terminal fitting part, excellent micro-sliding wear characteristics are achieved in the terminal fitting part and a low friction coefficient comparable to that of the prior art is obtained, and excellent weldability comparable to that of the prior art is achieved in the welding part.

[0020] It was also found that if a structure in which a silver coating is formed on the entire surface of the blank and the above-mentioned composite coating is formed on the part that serves as the terminal fitting part is adopted, the terminal can be manufactured at low cost through a simple manufacturing process.

[0021] Based on the above, the inventors of the present invention completed the present invention. That is, the present invention is as follows.

[0022] [1] A composite material used in the manufacture of a terminal having a welding part and a terminal fitting part, which is a composite material formed with a metal coating and a composite coating on a blank, the metal coating containing at least one of silver and tin, the composite coating being composed of a silver layer containing carbon particles, and there being a part where the above-mentioned metal coating is exposed and a part where the above-mentioned composite coating is exposed in the composite material.

[0023] [2] The composite material according to [1], wherein the part where the above-mentioned metal coating is exposed in the composite material corresponds to the welding part of the above-mentioned terminal, and the part where the above-mentioned composite coating is exposed corresponds to the terminal fitting part of the above-mentioned terminal.

[0024] [3] A method for manufacturing a terminal, which processes the composite material according to [1] or [2] into the shape of a terminal.

[0025] [4] A terminal, which is a terminal having a welding part and a terminal fitting part formed with a coating on a blank, the above-mentioned coating including a metal coating and a composite coating, the metal coating being formed on the above-mentioned blank and containing at least one of silver and tin, the composite coating being formed on the above-mentioned blank and being composed of a silver layer containing carbon particles, the part where the metal coating is exposed in the above-mentioned terminal constituting the above-mentioned welding part, and the part where the composite coating is exposed in the above-mentioned terminal constituting the above-mentioned terminal fitting part.

[0026] [5] The terminal according to [4], wherein the above-mentioned terminal is a male terminal that fits with a female terminal having a receiving part.

[0027] [6] The terminal according to [4] or [5], wherein the metal coating film is a silver coating film made of silver formed on the entire surface layer of the blank, and a part of the silver coating film is formed with the composite coating film.

[0028] [7] The terminal according to any one of [4] to [6], wherein the thickness of the metal coating film is 0.01 to 2.0 μm.

[0029] [8] The terminal according to any one of [4] to [7], wherein the proportion of carbon particles in the surface of the composite coating film is 1 to 80 area %.

[0030] [9] The terminal according to any one of [4] to [8], wherein the thickness of the composite coating film is 0.5 to 15 μm.

[0031]

[10] The terminal according to any one of [4] to [9], wherein a base layer made of at least one selected from the group consisting of Cu, Ni, Sn, and Ag is formed on the blank, and the metal coating film and the composite coating film are formed on the base layer.

[0032]

[11] The terminal according to any one of [4] to

[10] , further having a spacer for separating the welding portion and the terminal fitting portion.

[0033]

[12] A method for manufacturing a terminal, comprising the following steps: forming a metal coating film and a composite coating film on a blank, and processing the obtained composite material into the shape of a terminal, wherein the metal coating film contains at least one of silver and tin, the composite coating film is composed of a silver layer containing carbon particles, the portion of the terminal where the metal coating film is exposed constitutes the welding portion, and the portion of the terminal where the composite coating film is exposed constitutes the terminal fitting portion.

[0034]

[13] A method for manufacturing a terminal, comprising the following steps: processing a blank into the shape of a terminal, and forming a metal coating film and a composite coating film on the processed blank, wherein the metal coating film contains at least one of silver and tin, the composite coating film is composed of a silver layer containing carbon particles, the portion of the terminal where the metal coating film is exposed constitutes the welding portion, and the portion of the terminal where the composite coating film is exposed constitutes the terminal fitting portion.

[0035]

[14] A method for manufacturing a terminal, comprising the following steps: forming a silver coating film made of silver on the entire surface layer of a blank, forming a composite coating film composed of a silver layer containing carbon particles on a part of the silver coating film, processing the obtained composite material into the shape of a terminal, the portion of the terminal where the silver coating film is exposed constitutes the welding portion, and the portion of the terminal where the composite coating film is exposed constitutes the terminal fitting portion.

[0036]

[15] A method for manufacturing a terminal, comprising the following steps: processing a blank into the shape of a terminal, forming a silver coating film composed of silver on the entire surface of the processed blank, forming a composite coating film composed of a silver layer containing carbon particles on a part of the silver coating film, the part of the terminal where the silver coating film is exposed constituting a welding part, and the part of the terminal where the composite coating film is exposed constituting a terminal fitting part.

[0037]

[16] The method for manufacturing a terminal according to any one of

[12] to

[15] , wherein the terminal is a male terminal that fits into a female terminal having a receiving part.

[0038]

[17] The method for manufacturing a terminal according to

[14] or

[15] , wherein at least a part of a part of the part where the silver coating film is exposed and a part of the part where the composite coating film is exposed further constitutes a spacer that separates the welding part and the terminal fitting part.

[0039]

[18] The method for manufacturing a terminal according to

[14] ,

[15] or

[17] , wherein the thickness of the silver coating film is 0.01 to 2.0 μm.

[0040]

[19] The method for manufacturing a terminal according to

[14] or

[15] , wherein a base layer composed of at least one selected from the group consisting of Cu, Ni, Sn, and Ag is formed on the entire surface of the blank, and the silver coating film is formed on the entire surface of the base layer.

[0041] Effects of the Invention

[0042] According to the present invention, there is provided a terminal, a method for manufacturing the same, and a composite material that can be used to manufacture the aforementioned terminal. The terminal includes: a terminal fitting part that is not likely to cause micro-sliding wear and has a friction coefficient as low as the same level as the prior art; and a welding part that has welding properties as excellent as those of the prior art. Further, according to a preferred embodiment of the present invention, there is provided a terminal and a method for manufacturing the same that can be manufactured at low cost through a simple manufacturing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 is a schematic longitudinal sectional view of the composite material of the present invention.

[0044] Figure 2 is in Figure 1 way of (b) as an example to show the part where the metal coating film 14 is exposed (metal coating film exposed part 18), etc.

[0045] Figure 3 is a schematic longitudinal sectional view of the composite material of the present invention having a spacer.

[0046] Figure 4 It is a schematic view of the shape when observing one embodiment of the terminal of the present invention from the upper surface (the perspective from which the composite coating film can be seen).

[0047] Figure 5 It is a schematic longitudinal sectional view of the terminal of the present invention having a spacer portion.

[0048] Figure 6 It is a schematic longitudinal sectional view of the terminal of the present invention in a manner of mounting a housing member.

[0049] Figure 7 It is a schematic longitudinal sectional view of a male terminal and a female terminal. Detailed Embodiments

[0050] Hereinafter, embodiments of the present invention will be described.

[0051] [Composite Material]

[0052] The composite material of the present invention has the following structure: a metal coating film containing at least one of silver and tin and a composite coating film composed of a silver layer containing carbon particles are formed on a blank, and there are portions where the aforementioned metal coating film is exposed and portions where the aforementioned composite coating film is exposed. This composite material is used in the manufacture of terminals having a welding portion and a terminal fitting portion. Hereinafter, for each component of this composite material, while referring to the schematic longitudinal sectional view thereof, that is, Figure 1 it will be described. Figure 1 Two representative modes of the composite material 10 of the present invention are shown.

[0053] <Blank, Shape of the Blank and the Composite Material>

[0054] As the constituent material of the blank 12 on which the metal coating film and the composite coating film are formed, a material having the conductivity required for materials such as sliding electrical contact components such as switches and connectors is preferred. Further, from the viewpoint of cost, as the constituent material, Cu (copper) and Cu alloys are preferred. As the aforementioned Cu alloy, from the viewpoints of conductivity and strength, etc., an alloy composed of the following components is preferred: Cu; at least one selected from the group consisting of Si (silicon), Fe (iron), Mg (magnesium), P (phosphorus), Ni (nickel), Sn (tin), Co (cobalt), Zn (zinc), Be (beryllium), Pb (lead), Te (tellurium), Ag (silver), Zr (zirconium), Cr (chromium), Al (aluminum) and Ti (titanium); and inevitable impurities. The amount of Cu in the Cu alloy is preferably 85 mass% or more, more preferably 92 mass% or more (the amount of Cu is preferably 99.95 mass% or less).

[0055] The thickness of the blank 12 is not particularly limited, and from the viewpoint of coping with the miniaturization of terminals in recent years, it is preferably 0.05 to 1 mm, more preferably 0.1 to 0.6 mm. The blank 12 is typically in a flat shape (such as a flat plate shape), and after forming the metal coating 14 and the composite coating 16 to form the composite material 10, the composite material 10 is then formed into the shape of a terminal for its use. Conversely, the blank 12 can also be processed into the shape of a terminal, and then the metal coating 14 and the composite coating 16 are formed. The shape of the aforementioned composite material 10 is typically substantially the same as that of the blank 12, that is, a flat plate shape or the like. As described later, the composite material 10 of the present invention has a portion with excellent solder wettability, and a portion with excellent micro-sliding wear characteristics and a low friction coefficient. Therefore, it is suitable as a material for a terminal having a welding portion and a terminal fitting portion.

[0056] <Base layer>

[0057] The composite material 10 of the present invention may have the following structure: a base layer is formed on the blank ( Figure 1 not shown in the figure), and the metal coating 14 and the composite coating 16 are formed on the base layer. Especially when the metal coating 14 is a thin layer similar to a thickness of 0.1 μm or less, from the viewpoint of the heat resistance of the composite material 10, it is preferable to have a base layer. Examples of the constituent metal of the base layer include at least one metal or alloy selected from the group consisting of Cu, Ni, Sn, and Ag. It should be noted that the base layer can be a single layer composed of Cu, Ni, Sn, Ag, or their alloys respectively, or a layer formed by combining them (laminated structure). For the formation of the base layer, the entire surface layer of the blank can be processed according to the use of the composite material 10 to be manufactured, or a part of it can be processed. In addition, from the viewpoint of the manufacturability of the composite material 10, the constituent metal of the base layer is preferably at least one metal or alloy selected from the group consisting of Cu, Ni, and Ag.

[0058] For example, in order to prevent copper in the blank 12 from diffusing to the surfaces of the metal coating 14 and the composite coating 16, resulting in deterioration of conductivity, it is preferable to form a base layer composed of Ni. When the blank 12 is a zinc-containing copper alloy such as brass, in order to prevent zinc in the blank 12 from diffusing to the surfaces of the metal coating 14 and the composite coating 16, it is preferable to form a base layer composed of Cu. In order to improve the adhesion of the metal coating 14 and the composite coating 16 to the blank 12, it is preferable to form a base layer composed of Ag. The thickness of the base layer is not particularly limited, and from the viewpoints of its function and cost, it is preferably 0.05 to 2 μm, more preferably 0.15 to 1 μm.

[0059] <Metal coating>

[0060] In the composite material of the present invention, a metal coating film 14 is formed on the blank 12 or on the base layer described above. The metal coating film 14 contains at least one of silver and tin. More specifically, the metal coating film 14 is, for example, a coating film composed of a single metal of silver or tin, or a coating film composed of an alloy of silver and tin. The aforementioned metal and alloy may contain inevitable impurities.

[0061] Both silver and tin are metals with excellent solder wettability. Therefore, the metal coating film 14 is suitable as the soldering portion of the terminal. For solder wettability, tin is particularly excellent. On the other hand, when forming a metal coating film composed of tin, the occurrence of whiskers (a cause of short circuit) becomes a problem. To prevent this problem, a reflow soldering (heating) process and other supplementary processes are required to reduce internal stress. For silver, although the solder wettability is not as good as that of tin, it is still sufficient for practical use, can be manufactured through a simple process without whisker problems, and is also more excellent than tin in terms of heat resistance and conductivity.

[0062] The metal coating film 14 can be formed on the entire surface of the surface layer of the blank 12 or on a part thereof. In addition, as long as good solder wettability can be exhibited, the thickness of the metal coating film 14 is not particularly limited, but it is preferably 0.01 to 2.0 μm. Considering cost, it is more preferably 0.01 to 0.8 μm, further preferably 0.015 to 0.6 μm, and particularly preferably 0.02 to 0.2 μm.

[0063] <Composite coating film>

[0064] The composite coating film 16 constituting the composite material of the present invention is composed of a silver layer containing carbon particles. The composite coating film 16 can be directly formed on the blank 12 (for example Figure 1 the structure of (a)), or can be formed on a part of the metal coating film 14 formed on the blank (for example Figure 1 the structure of (b)). In the silver layer constituting the composite coating film 16, carbon particles are (preferably approximately uniformly) dispersed in the matrix composed of silver.

[0065] (Carbon particles)

[0066] The composite coating 16 contains carbon particles, so that the micro-sliding wear characteristics of the coating are excellent and the friction coefficient is low. From the viewpoint of exerting this function, the carbon particles are preferably graphite particles. From the viewpoint of the micro-sliding wear characteristics and low friction coefficient of the composite coating 16, the average primary particle size of the carbon particles is preferably 0.5 to 15 μm, more preferably 1 to 10 μm. It should be noted that the average primary particle size refers to the average value of the major diameter of the particles, and the major diameter refers to the length of the longest line segment that can be drawn in the particle in the image (plane) obtained by observing the carbon particles in the composite coating 16 of the composite material at an appropriate observation magnification. In addition, the major diameter is set to the value obtained for more than 50 particles. Moreover, the shape of the carbon particles is not particularly limited to approximately spherical, scaly, amorphous, etc., but from the viewpoint of smoothing the surface of the composite coating 16 to improve the micro-sliding wear characteristics of the composite material and reduce the friction coefficient, it is preferably a scaly shape.

[0067] (Vickers hardness)

[0068] The composite film 16 of the composite material 10 of the present invention preferably has high hardness, and specifically, its Vickers hardness Hv is preferably 100 or more, more preferably 120 to 230. As a result, the composite film 16 becomes difficult to be ground due to its high hardness, and the composite material 10 has particularly excellent micro-sliding wear characteristics.

[0069] (Carbon content and area ratio)

[0070] As described above, the composite coating 16 in the embodiment of the composite material 10 of the present invention contains carbon particles. From the viewpoint of the micro-sliding wear characteristics, low friction coefficient and conductivity of the composite material 10, the carbon content in the composite coating 16 is preferably 1 to 50 mass%, more preferably 1.5 to 40 mass%, and further preferably 2 to 35 mass%.

[0071] In addition, the ratio (area ratio) of carbon particles in the surface of the composite coating 16 containing carbon particles is an indicator of micro-sliding wear characteristics and low friction coefficient. From the perspective of the balance between these two characteristics and conductivity, it is preferably 1 to 80 area %, and more preferably 12 to 50 area %. It should be noted that sometimes there are carbon particles on the surface of the composite coating 16 that are only attached and easy to fall off. In this case, the same ultrasonic cleaning treatment as described in the later (partial removal of carbon particles on the surface of the composite coating) is first performed, and then the area ratio of carbon particles on the surface of the composite coating 16 is calculated. The details of the method for measuring the aforementioned area ratio will be described in the examples.

[0072] (Elemental composition of composite coating)

[0073] Regarding the elemental composition of the composite coating film 16 in the embodiment of the composite material 10 of the present invention, it is typically substantially composed of silver and carbon (for example, when performing EDX analysis using an energy dispersive X-ray analyzer, the total content of silver and carbon in the composite coating film 16 is 100% by mass).

[0074] (Thickness of the composite coating film)

[0075] The thickness of the composite coating film 16 is not particularly limited, but from the viewpoints of micro-sliding wear characteristics, low friction coefficient, and conductivity, it is preferably a minimum thickness. In addition, even if the thickness is too large, the effect of the composite coating film 16 has saturated, and the raw material cost will increase. From the above viewpoints, the thickness of the composite coating film 16 is preferably 0.5 to 15 μm, more preferably 0.6 to 8 μm, and further preferably 0.7 to 6 μm. It should be noted that the thickness of the composite coating film 16 is measured using a fluorescent X-ray film thickness meter, and the details of the measurement method will be described in the examples.

[0076] <Part corresponding to the welding part and part corresponding to the terminal fitting part>

[0077] As described above, the composite material 10 of the present invention has a structure in which a metal coating film 14 and a composite coating film 16 are formed on the blank 12. Moreover, there is a part where the metal coating film 14 is exposed in the composite material 10. "Exposed" means that the aforementioned "part" is not covered by the composite coating film 16 or other layers. In other words, it means that the aforementioned "part" constitutes a part of the outermost surface of the composite material 10. Taking Figure 1 way (b) as an example, the aforementioned part where the metal coating film 14 is exposed (metal coating film exposed part 18) is shown in Figure 2 .

[0078] Since the metal coating film exposed part 18 has good solder wettability, it can function well as the welding part in the terminal having the welding part and the terminal fitting part. That is, when processing the composite material 10 into a terminal, it is preferable to use the metal coating film exposed part 18 as the welding part.

[0079] There is a part where the composite coating film 16 is exposed in the composite material 10. "Exposed" means that the aforementioned "part" is not covered by the metal coating film 14 or other layers. In other words, the aforementioned "part" constitutes a part of the outermost surface of the composite material 10. The micro-sliding wear characteristics of the composite coating film exposed part 20 are excellent and the friction coefficient is low, so it can function well as the terminal fitting part in the terminal having the welding part and the terminal fitting part. That is, when processing the composite material 10 into a terminal, it is preferable to use the composite coating film exposed part 20 as the terminal fitting part.

[0080] <Part corresponding to the spacer>

[0081] As described above, the composite material 10 of the present invention is suitable as a material for a terminal having a welding portion and a terminal fitting portion. As will be described later, there may be a spacer portion that separates the welding portion and the terminal fitting portion in such a terminal.

[0082] In this case, as Figure 3 shown, the whole or a part of the portion 22 between a part of the exposed portion 18 of the metal coating film and a part of the exposed portion 20 of the composite coating film is the spacer portion. Details of the spacer portion will be described in the section regarding the description of the terminal of the present invention hereinafter.

[0083] <Use of the composite material>

[0084] The composite material of the present invention described above is suitable for use in the manufacture of a terminal having a welding portion and a terminal fitting portion. As a specific example of the aforementioned terminal, a terminal for a printed circuit board can be cited.

[0085] [Manufacturing method of the composite material]

[0086] Next, the manufacturing method of the composite material of the present invention described above will be described.

[0087] <Blank>

[0088] As described above, Cu and Cu alloys are preferably used as the constituent materials of the blank. As the aforementioned Cu alloy, an alloy composed of the following components is preferred: Cu; at least one selected from the group consisting of Si, Fe, Mg, P, Ni, Sn, Co, Zn, Be, Pb, Te, Ag, Zr, Cr, Al, and Ti; and inevitable impurities. The amount of Cu in the Cu alloy is preferably 85% by mass or more, more preferably 92% by mass or more (the amount of Cu is preferably 99.95% by mass or less). The thickness of the blank is preferably 0.05 to 1 mm, more preferably 0.1 to 0.6 mm. In addition, the shape of the blank is typically a flat shape (such as a flat plate shape). Such blanks are commercially available and can be manufactured by conventionally known methods.

[0089] <Formation of the base layer>

[0090] When forming the base layer in the composite material of the present invention, the forming method is not particularly limited. It should be noted that, as described above, as the constituent metal of the base layer, at least one metal or alloy selected from the group consisting of Cu, Ni, Sn, and Ag can be cited. From the viewpoint of manufacturability, at least one metal or alloy selected from the group consisting of Cu, Ni, and Ag is preferred. Its thickness is preferably 0.05 to 2 μm, more preferably 0.15 to 1 μm.

[0091] For example, by using a plating solution containing ions of the constituent metals of the base layer and performing electroplating by a known method, the base layer can be formed. In addition, the base layer can be formed on the entire surface layer of the blank as described above, or can be formed on a part of the surface layer of the blank.

[0092] <Formation of Metal Coating>

[0093] As described above, the metal coating contains at least one of silver and tin. From the viewpoint of solder wettability, tin is preferred. From the viewpoints of simplicity of manufacturing process, heat resistance, and conductivity, silver is preferred. The thickness of the metal coating is preferably 0.01 - 2.0 μm, more preferably 0.01 - 0.8 μm, still more preferably 0.015 - 0.6 μm, and particularly preferably 0.02 - 0.2 μm.

[0094] The metal coating can be formed on the blank by a conventionally known method. For example, methods such as electroplating using a plating solution containing ions of the constituent metals of the metal coating and evaporation plating can be adopted. In the case of forming a tin coating, in order to remove internal stress to prevent the formation of whiskers, a reflow soldering (heating) treatment is performed. In addition, after laminating and forming a silver layer and a tin layer on the blank and then heating, a coating composed of these alloys can also be formed.

[0095] <Method for Forming Composite Coating>

[0096] As described above, the composite coating is composed of a silver layer containing carbon particles. The Vickers hardness Hv of the composite coating is preferably 100 or more, more preferably 120 - 230. The carbon content in the composite coating is preferably 1 - 50 mass%, more preferably 1.5 - 40 mass%, still more preferably 2 - 35 mass%. The proportion (area ratio) of carbon particles in the surface of the composite coating is preferably 1 - 80 area%, more preferably 12 - 50 area%. For the elemental composition of the composite coating, typically it is substantially composed of silver and carbon. The thickness of the composite coating is preferably 0.5 - 15 μm, more preferably 0.6 - 8 μm, still more preferably 0.7 - 6 μm.

[0097] The composite coating can be formed by a conventionally known method. Hereinafter, as a representative method, a method for forming a composite coating by incorporating carbon particles into a silver coating by electroplating will be described.

[0098] (Silver Flash Plating)

[0099] Preferably, before forming the composite coating film on the blank, a very thin intermediate layer (silver flash plating layer) is formed by silver flash plating to improve the adhesion between the blank and the composite coating film. It should be noted that in the case of forming a base layer on the blank, silver flash plating is performed on the base layer (thereby improving the adhesion between the base layer and the composite coating film). As a method for performing silver flash plating, as long as the effects of the present invention are not impaired, a conventionally known method can be adopted without particular limitation. In addition, as described above, although the metal coating film in the composite material is very thin, it can still exhibit sufficiently excellent solder wettability. Therefore, in the case where the metal coating film is a silver coating film, by performing silver flash plating on the portion where the metal coating film is formed and the portion where the composite coating film is formed, a metal coating film composed of silver and a silver flash plating layer for forming the composite coating film thereon can be formed simultaneously. In terms of the simplicity of the manufacturing process, this is very advantageous. It should be noted that the silver flash plating layer is generally a thin layer, but in the present invention, its thickness is preferably adjusted within the range of 0.01 to 2.0 μm.

[0100] (Electroplating)

[0101] After forming the silver flash plating layer, electroplating is performed using a silver plating solution containing carbon particles to form a silver matrix and incorporate the carbon particles therein, thereby forming a composite coating film in which carbon particles are contained in the silver layer on the blank. It should be noted that the composite coating film can be directly formed on the blank or on a part of the metal coating film formed on the blank.

[0102] The aforementioned silver plating solution contains silver ions. From the viewpoints of the formation rate of the composite coating film and suppressing the appearance unevenness of the composite coating film, the concentration of silver in the silver plating solution is preferably 5 to 150 g / L, more preferably 10 to 120 g / L, and most preferably 20 to 100 g / L.

[0103] The aforementioned silver plating solution contains carbon particles. As described above, the shape of the carbon particles is not particularly limited to a substantially spherical shape, a flake shape, an amorphous shape, etc., and a flake shape is preferred. From the viewpoint of easy incorporation into the silver matrix, the volume-based cumulative 50% particle size (D50) of the carbon particles measured by a laser diffraction / scattering type particle size distribution measuring device is preferably 0.5 to 15 μm, more preferably 1 to 10 μm. In addition, it is preferable to perform an oxidation treatment on the carbon particles to remove the lipophilic organic substances adsorbed on the surface of the carbon particles to improve the dispersibility of the carbon particles in the silver plating solution. The specific method of the oxidation treatment is publicly known.

[0104] Furthermore, the surface treatment of the carbon particles that have undergone the above oxidation treatment with a polymer can also be performed as needed. Thereby, the smoothness of the surface of the composite coating film formed using the above silver plating solution can be improved.

[0105] Specifically, in the presence of a polymer, the aforementioned carbon particles are stirred and mixed in water. At this time, it is considered that the polymer adheres to the carbon particles through the functional groups and three-dimensional structure of the aforementioned polymer. After the aforementioned stirring and mixing, filtration and washing of the filtrate (carbon particles surface-treated with the polymer) can also be performed.

[0106] The weight-average molecular weight of the polymer (molecular weight converted from standard polyethylene glycol and standard polyethylene oxide measured by GPC) is preferably 1000 or more and 150,000 or less. In addition, specific examples of the polymer include: poly(diallyldimethylammonium chloride), diallylamine hydrochloride·acrylamide copolymer.

[0107] When surface-treating the carbon particles (when stirring and mixing the carbon particles in water in the presence of the polymer as described above), the concentration of carbon particles in water is preferably 200 g / L or less (usually 10 g / L or more, more preferably 50 to 120 g / L). With respect to 100 parts by mass of the carbon particles, the usage amount of the polymer is preferably 10 to 150 parts by mass (more preferably 20 to 100 parts by mass), the liquid temperature is preferably 15°C or more and 60°C or less, and the time for surface treatment (stirring and mixing) is preferably 3 hours or more and 30 hours or less. Washing can be carried out until the conductivity of the filtrate reaches 10 μS / cm or less.

[0108] Regarding the concentration of carbon particles in the silver plating solution, from the viewpoints of the micro-sliding wear characteristics of the obtained composite material, reducing the friction coefficient, and the limited amount of carbon particles that can be introduced into the composite coating film, it is preferably 10 to 150 g / L, more preferably 15 to 120 g / L, and particularly preferably 30 to 100 g / L.

[0109] The silver plating solution preferably contains a compound A represented by the following general formula (1). It is considered that the compound A inhibits the crystal growth of silver by adsorbing on the surface of the deposited silver, thereby reducing the crystal size of silver in the composite coating film formed by electroplating and improving the hardness of the composite coating film.

[0110] [Chemical formula 1]

[0111]

[0112] In formula (1), m is an integer from 1 to 5, Ra is a carboxyl group, Rb is an aldehyde group, carboxyl group, amino group, hydroxyl group, or sulfonic acid group, Rc is hydrogen or an arbitrary substituent, and Ra and Rb can each independently be bonded to the benzene ring via a divalent group composed of at least one selected from the group consisting of -O- and -CH2-. Examples of the aforementioned divalent group include: -CH2-CH2-O-, -CH2-CH2-CH2-O-, (-CH2-CH2-O-) n (n is an integer of 2 or more).

[0113] In formula (1), when m is 2 or more, the multiple Rb's present are each independently the same or different, and when m is 3 or less, the multiple Rc's present are each independently the same or different. For Rc, examples of the "optional substituent" include: an alkyl group having 1 to 10 carbon atoms, an alkylaryl group, an acetyl group, a nitro group, a halogen group, and an alkoxy group having 1 to 10 carbon atoms.

[0114] From the viewpoints of suppressing the appearance unevenness of the composite coating film and appropriately controlling the crystal grain size of silver in the formed composite coating film, the concentration of compound A in the silver plating solution is preferably 2 to 250 g / L, more preferably 3 to 200 g / L.

[0115] The silver plating solution used in the present invention preferably contains a complexing agent. The complexing agent complexes silver ions in the silver plating solution to improve their stability as ions. From the viewpoint of the stability of the formed complex, a compound having a sulfonic acid group is preferred as the complexing agent, such as an alkylsulfonic acid having 1 to 12 carbon atoms, an alkanolsulfonic acid having 1 to 12 carbon atoms, and a hydroxyarylsulfonic acid.

[0116] The silver plating solution may further contain a brightening agent, a curing agent, and a conductive salt.

[0117] In addition, the solvent constituting the silver plating solution is mainly water. Water is preferred from the viewpoints of the solubility of (complexed) silver ions, the solubility of other components contained in the plating solution, and the small environmental load. In addition, a mixed solvent of water and an alcohol can also be used as the solvent.

[0118] Electroplating is carried out using the silver plating solution described above. The blank to be electroplated is used as the cathode. For example, a silver electrode plate that dissolves and supplies silver ions is used as the anode. The cathode and the anode are immersed in the silver plating solution (plating bath), and current is passed through to carry out silver plating. From the viewpoints of the formation rate of the composite coating film and suppressing the appearance unevenness of the composite coating film, the current density here is preferably 0.5 to 10 A / dm 2 , more preferably 1 to 8 A / dm 2 , further preferably 1 to 5 A / dm 2 . From the viewpoints of the production efficiency of plating and preventing excessive evaporation of the liquid, the temperature of the plating bath (silver plating solution) during electroplating (plating temperature) is preferably 15 to 50 °C, more preferably 20 to 45 °C. The time for silver plating (the time for applying current) can be appropriately adjusted according to the thickness of the target composite coating film, and typically ranges from 25 to 1800 seconds.

[0119] (Partial removal treatment of carbon particles on the surface of the composite coating film)

[0120] For example, on the surface of the composite coating formed on the blank by electroplating described above, there will be: carbon particles that are incorporated (embedded) into the silver matrix and are not easily detached; and carbon particles that are rather attached to the surface than incorporated and are easily detached. The latter may contaminate the equipment when the composite material is bent or processed. Therefore, it is preferable to clean and remove such carbon particles. One of the cleaning methods is to perform ultrasonic cleaning treatment on the surface of the composite coating. The ultrasonic cleaning is preferably carried out at 20 to 100 kHz for 1 to 300 seconds. In addition, as another cleaning method, electrolytic cleaning treatment can be cited. In this case, the electrolytic cleaning is preferably carried out at 1 to 30 A / dm 2 for 10 to 300 seconds.

[0121] [Terminal]

[0122] Next, the terminal of the present invention will be described.

[0123] The terminal of the present invention is formed by forming a coating on a blank and has a welding portion and a terminal fitting portion. The aforementioned coating includes a metal coating and a composite coating. The metal coating is formed on the aforementioned blank and contains at least one of silver and tin. The composite coating is formed on the aforementioned blank and is composed of a silver layer containing carbon particles. The portion of the terminal exposing the metal coating constitutes the aforementioned welding portion, and the portion of the terminal exposing the composite coating constitutes the aforementioned terminal fitting portion. Hereinafter, each component of the terminal of the present invention will be described.

[0124] <Blank>

[0125] The aforementioned blank is the same as the blank in the composite material of the present invention. As its constituent material, Cu and Cu alloys are preferred. As the aforementioned Cu alloy, an alloy composed of the following components is preferred: Cu; at least one selected from the group consisting of Si, Fe, Mg, P, Ni, Sn, Co, Zn, Be, Pb, Te, Ag, Zr, Cr, Al, and Ti; and inevitable impurities. The amount of Cu in the Cu alloy is preferably 85% by mass or more, more preferably 92% by mass or more (the amount of Cu is preferably 99.95% by mass or less). The thickness of the blank is preferably 0.05 to 1 mm, more preferably 0.1 to 0.6 mm.

[0126] <Base layer>

[0127] The terminal of the present invention may have the following structure: a base layer is formed on a blank, and a metal coating film and a composite coating film are formed thereon. The aforementioned base layer is the same as the base layer in the composite material of the present invention. As the constituent metals thereof, at least one metal or alloy selected from the group consisting of Cu, Ni, Sn, and Ag can be mentioned. From the viewpoint of the manufacturability of the terminal, it is preferably at least one metal or alloy selected from the group consisting of Cu, Ni, and Ag, and its thickness is preferably 0.05 to 2 μm, more preferably 0.15 to 1 μm.

[0128] <Metal coating film>

[0129] The metal coating film of the terminal of the present invention is the same as the metal coating film of the composite material of the present invention. It contains at least one of silver and tin. From the viewpoint of solder wettability, tin is preferred. From the viewpoints of simplicity of manufacturing process, heat resistance, and conductivity, silver is preferred. The metal coating film can be formed on the entire surface of the blank or on a part thereof. The thickness of the metal coating film is preferably 0.01 to 2.0 μm, more preferably 0.01 to 0.8 μm, still more preferably 0.015 to 0.6 μm, and particularly preferably 0.02 to 0.2 μm.

[0130] <Composite coating film>

[0131] The composite coating film in the terminal of the present invention is the same as the composite coating film in the composite material of the present invention. It is composed of a silver layer containing carbon particles. The average primary particle size of the carbon particles is preferably 0.5 to 15 μm, more preferably 1 to 10 μm. The Vickers hardness Hv of the composite coating film is preferably 100 or more, more preferably 120 to 230. The carbon content in the composite coating film is preferably 1 to 50% by mass, more preferably 1.5 to 40% by mass, still more preferably 2 to 35% by mass. The proportion (area ratio) of the carbon particles in the surface of the composite coating film is preferably 1 to 80 area%, more preferably 12 to 50 area%. For the elemental composition of the composite coating film, typically, it is substantially composed of silver and carbon. The thickness of the composite coating film is preferably 0.5 to 15 μm, more preferably 0.6 to 8 μm, still more preferably 0.7 to 6 μm.

[0132] <Terminal fitting portion>

[0133] As described above, the terminal fitting portion in the terminal of the present invention is constituted by the portion of the terminal where the composite coating film is exposed. "Exposed" means that the aforementioned "portion" is not covered by the metal coating film or other layers. In other words, the aforementioned "portion" constitutes a part of the outermost surface of the terminal. The terminal fitting portion is basically located at one end of the terminal. Since the surface of this terminal fitting portion is composed of the composite coating film, it has excellent micro-sliding wear characteristics and a low friction coefficient.

[0134] Specifically, when the micro-sliding wear characteristics test in the embodiment described later is implemented, after 5000 reciprocating sliding actions, the center of the sliding traces of the test piece with indentation and the flat test piece are observed at a magnification of 200 times using a microscope (VHX-1000 manufactured by KEYENCE CORPORATION), and it is confirmed that the blank is not exposed from any sliding trace. In addition, the friction coefficient measured by the method in the embodiment described later is 0.50 or less, preferably 0.40 or less, and more preferably 0.30 or less. It should be noted that the friction coefficient is usually 0.01 or more.

[0135] The terminal fitting portion is a laminate of a blank and a composite coating, a laminate of a blank, a metal coating, and a composite coating (if there is an exposed portion of the composite coating, it may also be another layer). A schematic diagram of the shape of one embodiment of the terminal of the present invention when viewed from the top surface (from a perspective where the composite coating can be seen) is shown in Figure 4 .

[0136] Typically, the terminal is a set of a male terminal and a female terminal having a terminal fitting portion for receiving the male terminal. The terminal of the present invention is suitable as a male terminal, as described below. The terminal fitting portion 30 of the terminal of the present invention is typically formed in the shape of a rod such as a pin or a convex piece (cylindrical, polygonal, etc.), a convex shape, a slender plate shape, or a combination of these. Figure 4 In the embodiment shown, the front end of the rectangular parallelepiped is rounded and slightly tapered (a type of convex shape).

[0137] The surface of the terminal fitting portion 30 is formed by a composite coating, but the coating has lower solder wettability than a metal coating. The metal coating shows excellent wettability to solder heated to about 250°C, but the composite coating hardly wets the solder at this temperature, and shows acceptable solder wettability for practical use when heated to a high temperature of 350°C or higher.

[0138] <Welding Department>

[0139] Next, refer to Figure 4The welding portion of the terminal of the present invention will be described. The welding portion 32 is constituted by the portion of the terminal where the metal coating film is exposed. "Exposed" means that the aforementioned "portion" is not covered by a composite coating film or other layers, in other words, the aforementioned "portion" constitutes a part of the outermost surface of the terminal. The welding portion 32 is substantially located at the end portion on the side opposite to the terminal fitting portion 30. The metal coating film is constituted by at least one of silver and tin, which are metals having excellent solder wettability. Therefore, the aforementioned welding portion 32 exhibits excellent solder wettability equivalent to that of the prior art. Specifically, in the case of conducting the solder wetting test (a test for obtaining the solder wettability after heat aging) described in the following embodiments, the welding portion 32 shows a solder wetting area ratio of 80 area% or more. The solder wetting area ratio of the welding portion 32 is preferably 90 area% or more, more preferably 95 area% or more. Furthermore, in the case where the metal coating film is substantially constituted by silver, since silver is a metal having excellent heat resistance, the welding portion 32 exhibits excellent solder wettability. However, in the case where the silver coating film is a thin layer similar to 0.1 μm or less, in order to achieve excellent solder wettability, it is preferable to form a base layer to suppress atomic diffusion from the blank to the surface of the silver coating film.

[0140] The welding portion 32 is typically a laminate of a blank and a metal coating film (if there is an exposed portion of the metal coating film, it may also be other layers). When looking down at the terminal of the present invention, the shape of the welding portion 32 is, for example, a rod shape such as a round rod or a square rod, an elongated plate shape, or a shape formed by combining these.

[0141] <Spacer portion>

[0142] The terminal of the present invention may further have a spacer portion that separates the welding portion and the terminal fitting portion. Figure 5 The schematic longitudinal cross-sectional view of the terminal of the present invention having a spacer portion is shown.

[0143] The housing member described below can be installed at the spacer portion 34. As described later, the terminal of the present invention is manufactured, for example, by punching a composite material of the present invention (having a structure of a metal coating film and a composite coating film on a blank), and the terminal fitting portion 30, the welding portion 32, and the spacer portion 34 can be simultaneously formed by this punching. That is, typically, they are integrally formed. When the metal coating film exposed portion 42 has only the minimum size as the welding portion and the composite coating film exposed portion 44 has only the minimum size as the terminal fitting portion, there is no spacer portion. On the other hand, if the sizes of the metal coating film exposed portion 42 and / or the composite coating film exposed portion 44 are designed to be longer than the aforementioned minimum size, the spacer portion 34 can be formed. That is, the spacer portion 34 is composed of at least a part of a part of the metal coating film 38 and a part of the composite coating film 40, and a part of the blank 36 corresponding to this part. "The part of the blank 36 corresponding to this part" means the part of the blank 36 located vertically below the aforementioned "this part" when the terminal is placed horizontally.

[0144] If the terminal of the present invention is bent at the portion of the spacer portion 34, product designs with different shapes from the unbent straight terminals can be made, such as connectors. From the viewpoints of being able to install the housing member described next and the degree of freedom of such product design, the spacer portion 34 is useful.

[0145] <Housing member>

[0146] As described above, the housing member can be installed at the spacer portion 34. A schematic diagram of a longitudinal cross-section of the terminal in the manner of installing the housing member is shown in Figure 6 .

[0147] The housing member 50 is installed at the position of the spacer portion 34. Typically, the housing member 50 has a box shape with an opening, and a plurality of holes through which the terminal 60 can pass are provided in the wall surface opposite to the aforementioned opening. The number of holes can be appropriately adjusted according to the use of the terminal. The welding portion 32 of the terminal 60 is located outside the box shape of the housing member 50, and the terminal fitting portion 30 is located inside the box shape of the housing member 50 (on the opening side when viewed from the aforementioned holes). In addition, at the portion of the spacer portion 34 where the hole of the housing member 50 passes through, a housing fixing portion X can be provided to prevent the terminal 60 from easily coming out of the housing member 50. Further, at the position of the aforementioned opening of the housing member 50, a terminal fixing portion Y capable of being fixed to a female terminal described later can also be provided.

[0148] The housing member 50 is made of an insulating material, and as an example of this material, resin can be cited.

[0149] <Specific form of the terminal>

[0150] Regarding the specific manner of the terminals of the present invention, the terminals are typically a set of male terminals and female terminals, and the terminals of the present invention are preferably male terminals. Hereinafter, for the male terminals and female terminals, while referring to the schematic diagrams of their longitudinal cross-sections, namely Figure 7 an explanation will be given.

[0151] The female terminal 70 has a receiving portion 72, which is formed in the shape of a receiving portion for receiving the terminal fitting portion 30 of the male terminal 60, and has a fixing portion 74 inside it, which is used to fix the terminal fitting portion 30 of the inserted male terminal within the receiving portion 72 of the female terminal, thereby conducting electricity. As an example of the shape of the receiving portion 72, a cylindrical shape, a box-shaped (cuboid) shape can be cited. The terminal fitting portion 30 is inserted into the receiving portion 72, so that they are physically and electrically connected. In order to achieve good electrical connection, etc., the receiving portion 72 and the terminal fitting portion 30 are preferably made of the same material. In addition, the shape of the fixing portion 74 and the manner of fixing the terminal fitting portion 30 are not particularly limited as long as the inserted terminal fitting portion 30 can be fixed. For example, it can be a claw shape, a spring, etc.

[0152] In addition, a housing member 76 can also be installed on the female terminal 70. Representatively, the housing member 76 has a box-shaped shape with an opening, and a plurality of holes through which the female terminal 70 can pass are provided on one wall surface. The number of holes can be appropriately adjusted according to the use of the terminal. The receiving portion 72 of the female terminal 70 is located at the position of the opening of the housing member 76. The housing member 76 can also be provided with a terminal fixing portion P, which engages with the terminal fixing portion Y of the above-mentioned male terminal 60 to fix the male terminal 60 and the female terminal 70. Both the male terminal 60 and the female terminal 70 are provided with housing members, so that instead of aligning two small terminals, by aligning the housing members with each other, a plurality of male terminals 60 and female terminals 70 can be aligned and fitted together.

[0153] The constituent material of the housing member 76 is the same as that of the housing member 50 of the male terminal 60. It should be noted that the housing members 76 and 50 are preferably made of an elastically deformable material. In this case, by pressing the male terminal 60 and the female terminal 70 into each other in such a way that the terminal fitting portion 30 and the receiving portion 72 are fitted, the housing members 76 and 50 are deformed, so that the housing member 76 can enter the inside of the housing member 50 of the male terminal 60, and the two housing members are fixed by engaging the fixing portions P and Y.

[0154] <Terminal Use>

[0155] As a specific use of the terminals of the present invention having a welding portion and a terminal fitting portion described above, a terminal for a printed circuit board can be cited.

[0156] [Manufacturing Method of Terminals]

[0157] A method for manufacturing the terminal of the present invention will be described. In this manufacturing method, a metal coating film and a composite coating film are formed on a blank. The metal coating film contains at least one of silver and tin, and the composite coating film is composed of a silver layer containing carbon particles. It should be noted that, as described above, the terminal has an exposed portion of the metal coating film and an exposed portion of the composite coating film. However, by designing the size of at least one of them to be longer than the minimum sizes of the welding portion and the terminal fitting portion respectively, a spacer portion can be formed on the terminal.

[0158] Regarding the method for manufacturing the terminal of the present invention, there are: a method of forming a metal coating film and a composite coating film on a blank that has not been formed into a useful shape (such as a flat shape) to make a composite material and then processing it into a terminal shape (pre-formation of the coating film); and a method of processing the blank into a terminal shape and then forming a metal coating film and a composite coating film (post-formation of the coating film). Hereinafter, these two methods will be described.

[0159] <Pre-formation of the coating film>

[0160] In the method of pre-forming the coating film, first, the composite material of the present invention is manufactured (forming a metal coating film and a composite coating film on a flat blank). Then, by combining one or more of known processing methods such as blanking and bending, the composite material is processed into the desired terminal shape.

[0161] <Post-formation of the coating film>

[0162] In the method of post-forming the coating film, the blank is processed into the desired terminal shape by combining one or more of known processing methods such as blanking and bending. Then, for the blank formed into a terminal shape, the manufacturing method of the composite material of the present invention is implemented (forming a metal coating film and a composite coating film (further forming a base layer, etc. as required)).

[0163] <Various common structures in both pre-formation and post-formation of the coating film>

[0164] Next, various common structures in both the pre-formation method and the post-formation method of the coating film will be described.

[0165] (Blank, formation of the base layer, formation of the metal coating film, formation of the composite coating film)

[0166] Regarding these, they are the same as those described in the description part of the manufacturing method of the composite material of the present invention.

[0167] (Installation of the housing component)

[0168] For the terminals formed by each method, a housing component can be installed. For example, as described above with reference to Figure 6In the case of the housing member described above, which has a plurality of holes through which the terminals of the present invention can pass on the wall surface opposite to the opening, for example, the housing member is manufactured by injection molding using resin, and the terminals are inserted into the holes of the housing member and pressed in. Thus, an article in which the terminals penetrate through the plurality of holes of the housing member and are fixed by the housing fixing portion X can be obtained.

[0169] (In the case where the metal coating is a silver coating)

[0170] In the case where the metal coating is a silver coating, the terminals of the present invention can be manufactured by the simple method described below.

[0171] First, a silver coating made of silver is formed on the entire surface of the surface layer of the blank (or processed into the shape of the terminal when the coating is formed by the post-formation method), and then a composite coating is formed on a part of the silver coating (the part corresponding to the portion that becomes the terminal fitting portion). Through these two simple processes, a silver coating and a composite coating can be formed on the blank. On the other hand, in the case where the metal coating is a tin coating, in order to prevent whiskers, a supplementary treatment such as reflow soldering is required. In addition, in the case where the metal coating is a tin-containing coating such as a tin coating or a silver-tin alloy coating, sometimes the adhesion between the coating and the composite coating is insufficient, and it is preferable to directly form the metal coating and the composite coating on the blank (or the base layer when the base layer is formed) respectively. In this case, the following supplementary process occurs: when forming one coating, the part where the other coating is to be formed is masked, and the mask is removed (peeled off) after the coating formation is completed.

[0172] As described above, in the formation of the composite coating, from the viewpoint of the adhesion between the blank (or the base layer when there is a base layer) and the composite coating, it is preferable to perform silver flash plating on the blank (base layer) and then form the composite coating. And after performing silver flash plating on the entire surface of the blank surface layer, a composite coating is formed on a part of the formed silver flash plating layer. Although the above is the process of forming the composite coating, this process also forms a silver coating at the same time.

[0173] In addition, for the formation of the composite coating, if the method using a silver plating solution is used, by immersing a part of the blank (the part that becomes the terminal fitting portion) that has been silver flash plated in the silver plating solution to perform plating, a composite coating can be formed on a part of the silver coating without using a mask. Since there will be some fluctuations in the silver plating solution during plating, there will also be a situation where the boundary is not a straight line when observing the silver coating and the composite coating from above. However, if the terminal is designed to have a spacer in advance, and the spacer includes the size of the aforementioned boundary, there will be no particular problem.

[0174] Moreover, in the case of the above-described method of forming the film first, as described above, a blank (representatively in a flat plate shape) formed with a silver film and a composite film is processed into the shape of a terminal, thereby obtaining the terminal of the present invention. The obtained terminal has the following structure: a silver film made of silver is formed on the entire surface of the blank, and a part of the composite film is formed on the silver film.

[0175] Example

[0176] Hereinafter, embodiments of the present invention will be described in detail.

[0177] [Example 1] <Preparation and oxidation treatment of carbon particles>

[0178] 80 g of flake-shaped graphite particles (PAG-3000 manufactured by Nippon Graphite Industries, Co., Ltd.) with an average particle diameter of 5 μm as carbon particles were added to 1.4 L of pure water, and the mixture was heated to 50 °C while stirring. It should be noted that the aforementioned average particle diameter is the particle diameter at which the cumulative value based on volume measured using a laser diffraction / scattering particle size distribution measuring device (MT3300 (LOW-WET MT3000II Mode) manufactured by Microtrac BEL Corp.) is 50%. Next, 0.6 L of a 0.1 mol / L aqueous solution of potassium persulfate as an oxidizing agent was slowly added dropwise to the mixture, and then stirred for 2 hours for oxidation treatment. Then, filtration separation was performed using filter paper, and the obtained solid matter was washed with water.

[0179] <Silver flash plating>

[0180] A plate made of a Cu-Ni-Sn-P alloy (a copper alloy plate containing 1.0 mass% of Ni, 0.9 mass% of Sn, and 0.05 mass% of P, with the balance being Cu and inevitable impurities) (NB-109EH manufactured by DOWA METALTECH CO., LTD.) having a length of 5.0 cm, a width of 5.0 cm, and a thickness of 0.2 mm was prepared. Using this plate as a blank, using this blank as a cathode and an iridium oxide mesh electrode plate (obtained by coating an iridium oxide on a titanium mesh blank) as an anode, in a sulfonic acid-based silver flash plating solution at 25 °C containing methanesulfonic acid as a complexing agent (DAIN SILVER GPE-ST manufactured by DAIWA CHEMICAL CO., LTD. Silver concentration is 3 g / L, methanesulfonic acid concentration is 42 g / L), electroplating (silver flash plating) was performed at a current density of 5 A / dm 2 for 20 seconds. It should be noted that the silver flash plating is performed on the entire surface of the blank.

[0181] <AgC plating>

[0182] In a sulfonic acid-based silver plating solution containing methanesulfonic acid as a complexing agent, with a silver concentration of 30 g / L and a methanesulfonic acid concentration of 60 g / L (DAIN SILVER GPE-HB manufactured by DAIWA CHEMICAL CO., LTD, containing compound A belonging to the general formula (1) at a concentration of 4.2 g / L, and the solvent being mainly water), carbon particles (graphite particles) that have undergone the above oxidation treatment are added to prepare a carbon particle-containing sulfonic acid-based silver plating solution containing 50 g / L of carbon particles, 30 g / L of silver, and 60 g / L of methanesulfonic acid.

[0183] Next, using the blank material that has undergone silver flash plating as the cathode and a silver electrode plate as the anode, immerse the 2.5 cm long and 5.0 cm wide blank material that has undergone silver flash plating in the above carbon particle-containing sulfonic acid-based silver plating solution, and while stirring at 400 rpm using a stirrer, at a temperature of 25 °C and a current density of 3 A / dm 2 Electroplating is carried out for 120 seconds to obtain a composite material in which a composite coating film (AgC coating film) containing carbon particles in the silver layer is formed on the silver flash plating layer of the blank material. It should be noted that the composite coating film is formed on half of the surface layer (the area of 2.5 cm long and 5.0 cm wide) of the silver flash plating layer of the blank material. In addition, in the AgC plating, no mask is applied to the part of the blank material that has undergone silver flash plating and is not immersed in the plating solution.

[0184] Regarding the composite material obtained in this Example 1, consider the side where AgC plating is applied as the terminal fitting part, and the side where the silver flash plating layer is exposed without applying AgC plating as the welding part, and conduct the following evaluations.

[0185] <Thickness of the silver flash plating layer>

[0186] Using a fluorescent X-ray film thickness meter (FT110A manufactured by Hitachi High-Tech Science Corporation), measure the thickness of a circular area with a diameter of 0.2 mm in the central part of the exposed part (the surface of 2.5 cm × 5.0 cm) of the silver flash plating layer of the composite material. The result is 0.03 μm.

[0187] <Thickness of the composite coating film>

[0188] Using a fluorescent X-ray film thickness gauge (FT110A manufactured by Hitachi High-Tech Science Corporation), the thickness of a circular area with a diameter of 0.2 mm in the central part of a 2.5 cm × 5.0 cm surface on the welded part side of the composite material was measured. The thickness obtained thereby is the sum of the thicknesses of the composite coating film and the silver flash coating. Subtracting the thickness of the silver flash coating from this value yields the thickness of the composite coating film. As a result, the thickness of the composite coating film was 2 μm. Note that since the fluorescent X-ray film thickness gauge has difficulty detecting C atoms (carbon particles), the thickness was measured by detecting Ag atoms, but in the present invention, the thickness obtained thereby is regarded as the sum of the thicknesses of the composite coating film and the silver flash coating.

[0189] <Carbon area ratio on the surface of the composite coating film after ultrasonic cleaning treatment>

[0190] Using an ultrasonic cleaner (VS-100III manufactured by AS ONE, output power 100 W, tank size: length 140 mm × width 240 mm × depth 100 mm, the liquid used was pure water, and the water temperature was 20 °C), ultrasonic cleaning treatment was performed on the surface of the composite coating film of the obtained composite material at 28 kHz for 4 minutes.

[0191] The carbon area ratio on the surface of the composite coating film after ultrasonic cleaning treatment was measured as follows.

[0192] Using a bench microscope (TM4000Plus manufactured by Hitachi High-Tech Science Corporation), the surface of the composite coating film was observed at an acceleration voltage of 5 kV magnified 1000 times, and the obtained reflected electron composition (COMPO) image (one field of view) was binarized using GIMP 2.10.10 (image analysis software), and the area ratio of carbon on the surface of the composite coating film was calculated. Specifically, when the highest brightness among all pixels (880 × 1270 = 1,117,600 pixels) was set to 255 and the lowest brightness was set to 0, the gray scale was binarized such that pixels with a brightness of 127 or less were black and pixels with a brightness exceeding 127 were white, separated into the silver part (white part) and the carbon particle part (black part), and the ratio Q / P of the number of pixels Q of the carbon particle part to the number of pixels P of the entire image was calculated as the surface carbon area ratio (%). As a result, the carbon area ratio after ultrasonic cleaning treatment was 20 area%.

[0193] <Evaluation of micro-sliding wear characteristics>

[0194] A flat test piece with a width of 2.0 cm × a length of 3.0 cm was cut out from the terminal fitting part of the composite material obtained in Example 1 above.

[0195] On the other hand, test pieces with a width of 1.0 cm and a length of 4.0 cm were cut from the terminal fitting portions of the composite materials obtained from the above-described multiple fabricated Example 1, and indentation (extruded in a hemispherical shape) processing with an inner diameter of 1.0 mm was performed on them to obtain indented test pieces (indenters). Thus, in Example 1, both flat test pieces and indented test pieces were fabricated from the composite material (of the terminal fitting portion) of Example 1. The same applies to subsequent Examples and Comparative Examples (for example, in Example 2, both flat test pieces and indented test pieces were fabricated from the composite material of Example 2).

[0196] The abrasion test was conducted in the following manner to evaluate the micro-sliding abrasion characteristics: Using a sliding abrasion testing machine (CRS-G2050-DWA manufactured by Yamazaki Seiki Kenkyujo Co., Ltd.), on the above flat test piece, with the convex portion of the indented test piece contacting the flat test piece, while pressing the indented test piece against the flat test piece with a constant load (2 N), a reciprocating sliding motion was continuously performed (sliding distance 50 μm (one reciprocation is 100 μm), sliding speed 3 mm / s), and the abrasion states of the indented test piece and the flat test piece were confirmed. As a result, after 5000 reciprocating sliding motions, when observing the central portion of the sliding marks of the indented test piece and the flat test piece at a magnification of 200 times using a microscope (VHX-1000 manufactured by KEYENCE CORPORATION), it was confirmed that no (brown) base material was exposed from any of the sliding marks, indicating that the micro-sliding abrasion characteristics on the terminal fitting portion side of the composite material of Example 1 are excellent.

[0197] <Measurement of Coefficient of Friction>

[0198] Similar to the evaluation of the micro-sliding abrasion characteristics, flat test pieces and indented test pieces were fabricated using the terminal fitting portion of the composite material obtained in the above Example 1.

[0199] Then, using a sliding abrasion testing machine (CRS-G2050-DWA manufactured by Yamazaki Seiki Kenkyujo Co., Ltd.), with the convex portion of the indented test piece contacting the surface of the composite coating film of the flat test piece, while pressing the indented test piece against the flat test piece with a constant load (2 N), it was slid at a sliding speed of 0.4 mm / second, and the sliding load was measured from the start of sliding to a sliding distance of 5 mm. Then, the average of the sliding load data between a sliding distance of 2 mm and 3 mm was taken to obtain the coefficient of friction (average F of the sliding load / 5 N). As a result, the coefficient of friction of the terminal fitting portion was 0.20.

[0200] <Evaluation of Weldability>

[0201] A flat test piece with a width of 1.0 cm and a length of 2.5 cm was cut out from the welded part of the composite material obtained in Example 1 above. It was kept (aged) in the atmosphere at 155 °C for 16 hours and then evaluated under the test conditions shown below. As a result, the wetting area ratio was 85%, and it was found that the weldability of the welded part of the composite material of Example 1 was excellent.

[0202] [Test conditions]

[0203]

[0204] [Example 2]

[0205] Using the same blank as in Example 1 as the cathode and a Ni electrode plate as the anode, in a nickel plating bath (aqueous solution) composed of nickel sulfamate at a concentration of 342 g / L (80 g / L in terms of Ni concentration) and boric acid at a concentration of 45 g / L, while stirring at a liquid temperature of 55 °C and a current density of 4 A / dm 2 electroplating (Ni plating) was carried out for 40 seconds to form a Ni coating (Ni base layer) with a thickness of 0.2 μm on the blank. For the thickness of the base layer, it was measured by the same method as the method for finding the thickness of the composite coating.

[0206] Silver flash plating was performed on the blank with the Ni base formed, and except for this, the composite material was produced in the same manner as in Example 1.

[0207] For the obtained composite material, the thickness of the composite coating, the thickness of the silver flash plating layer, the carbon area ratio on the surface of the composite coating after ultrasonic cleaning treatment, and the friction coefficient were found in the same manner as in Example 1, and the micro-sliding wear characteristics and weldability were evaluated.

[0208] [Example 3]

[0209] Electroplating (silver flash plating) was carried out on the blank with the Ni base formed at a current density of 5 A / dm 2 for 150 seconds, and except for this, the composite material was produced in the same manner as in Example 2. For the obtained composite material, the thickness of the composite coating, the thickness of the silver flash plating layer, the carbon area ratio on the surface of the composite coating after ultrasonic cleaning treatment, and the friction coefficient were found in the same manner as in Example 1, and the micro-sliding wear characteristics and weldability were evaluated.

[0210] [Example 4]

[0211] At a current density of 5 A / dm 2The current density was electroplated (silver flash plating) on the blank with a Ni substrate for 375 seconds, and the composite material was produced in the same manner as in Example 2. For the obtained composite material, the thickness of the composite coating, the thickness of the silver flash plating layer, the carbon area ratio on the surface of the composite coating after ultrasonic cleaning treatment, and the friction coefficient were determined in the same manner as in Example 1, and the micro-sliding wear characteristics and weldability were evaluated.

[0212] [Example 5]

[0213] After adding 60 g of the carbon particles subjected to oxidation treatment used in Example 1 to 0.6 L of pure water, 100 g of an aqueous solution of poly(diallyldimethylammonium chloride) (weight average molecular weight: 1600, number average molecular weight: 1500) (UNISENCE FPA100L manufactured by SENKA Co., Ltd., the concentration of poly(diallyldimethylammonium chloride) is 25 to 35% by mass) was added, and the mixture was stirred and mixed at a liquid temperature of 25 °C for 24 hours to perform surface treatment on the carbon particles. Then, filtration separation was performed using filter paper, and the obtained solid matter was washed with water until the conductivity of the filtrate reached 10 μS / cm. It should be noted that the average molecular weight was measured by GPC (gel permeation chromatography). The details of the measurement conditions are as follows.

[0214] Eluent: water (containing sodium nitrate at a concentration of 0.1 mol / L and acetic acid at a concentration of 0.5 mol / L)

[0215] Standard substance: a mixture of polyethylene oxide (for standard substances with a molecular weight of 10,000 or more) and polyethylene glycol (for standard substances with a molecular weight of less than 10,000)

[0216] Sample concentration: 0.2 w / v%

[0217] Injection volume: 100 μL

[0218] Flow rate: 1.0 mL / minute

[0219] Chromatographic column: Shodex OHpak SB-806M HQ×2 (manufactured by Showa Denko K.K.)

[0220] Chromatographic column temperature: 40 °C

[0221] Pump: LC-10ADvp (manufactured by Shimadzu Corporation)

[0222] Detector: Shodex RI-71 (manufactured by Showa Denko K.K.)

[0223] As the carbon particles, the carbon particles (graphite particles) subjected to the above-described polymer-based surface treatment were used, and the plating time in the AgC plating was changed to 60 seconds. Except for this, the composite material was produced in the same manner as in Example 3. For the obtained composite material, the thickness of the composite coating, the thickness of the silver flash plating layer, the carbon area ratio on the surface of the composite coating after ultrasonic cleaning treatment, and the friction coefficient were determined in the same manner as in Example 1, and the micro-sliding wear characteristics and weldability were evaluated.

[0224] [Comparative Example 1] <Silver Flash Plating>

[0225] Half of the surface layer (an area of 2.5 cm in length and 5.0 cm in width) of a copper alloy plate made of Cu-Ni-Sn-P alloy (containing 1.0 mass% of Ni, 0.9 mass% of Sn, and 0.05 mass% of P, with the balance being Cu and unavoidable impurities) (NB-109EH manufactured by DOWAMETALTECH CO., LTD.) having a length of 5.0 cm, a width of 5.0 cm, and a thickness of 0.2 mm was subjected to silver flash plating. Except for this, the silver flash plating was carried out in the same manner as in Example 3.

[0226] <AgC Plating>

[0227] Using the blank subjected to the above silver flash plating as the cathode and a silver electrode plate as the anode, the portion of the blank that had been silver flash plated with a length of 2.5 cm and a width of 5.0 cm was immersed in a sulfonic acid-based silver plating solution containing carbon particles. Except for this, the composite material was produced in the same manner as in Example 1. For the obtained composite material, the thickness of the composite coating, the thickness of the silver flash plating layer, the carbon area ratio on the surface of the composite coating after ultrasonic cleaning treatment, and the friction coefficient were determined in the same manner as in Example 1, and the micro-sliding wear characteristics and weldability were evaluated. It should be noted that the thickness of the silver flash plating layer was measured before forming the composite coating. In addition, the weldability was evaluated on the portion of the blank where no plating was applied.

[0228] [Comparative Example 2]

[0229] In the same manner as in Example 3, a Ni-based bottom layer was formed on the blank, and then silver flash plating was carried out. Using the blank subjected to the silver flash plating as the cathode and a silver electrode plate as the anode, the blank that had been silver flash plated with a width of 5.0 cm and a length of 5.0 cm (the entire surface of the blank) was immersed in the same sulfonic acid-based silver plating solution containing carbon particles as used in Example 1, and while stirring with a stirrer at 400 rpm, electroplating was carried out at a temperature of 25°C and a current density of 3 A / dm 2 for 120 seconds to obtain a composite material in which a composite coating containing carbon particles in the silver layer was formed on the entire surface of the blank (the silver flash plating layer).

[0230] For the obtained composite materials, the thickness of the composite coating film, the thickness of the silver flash plating layer, the carbon area ratio on the surface of the composite coating film after ultrasonic cleaning treatment, and the coefficient of friction were determined in the same manner as in Example 1, and the micro-sliding wear characteristics and weldability were evaluated. It should be noted that the thickness of the silver flash plating layer was measured before forming the composite coating film. In addition, for the evaluation of weldability, a flat test piece with a size of 1.0 cm in width × 2.5 cm in length was cut out from the composite material of Comparative Example 1 (the outermost surface of the test piece except for the cut was composed of the composite coating film), and the evaluation was carried out using it.

[0231] [Comparative Example 3] <Sn plating>

[0232] A Sn plating solution was prepared, which was an aqueous solution containing 70 g / L of stannous sulfate (SnSO4) (39 g / L in terms of Sn concentration), 75 g / L of sulfuric acid (H2SO4), 30 g / L of cresol sulfonic acid as a leveling agent, and 2 g / L of polyoxyethylene stearylamine as a surfactant.

[0233] Using the same blank as in Example 1 as the cathode and a Sn electrode plate as the anode, a blank with a length of 5.0 cm and a width of 5.0 cm (the entire surface of the blank) was immersed in the above Sn plating solution, and while stirring with a stirrer at 400 rpm, electroplating was carried out at a temperature of 25 °C and a current density of 4 A / dm 2 for 55 seconds to obtain a plated material with a tin metal coating film (Sn coating film) formed on the blank. It should be noted that the metal coating film was formed on the entire surface of the blank surface layer (a region with a length of 5.0 cm and a width of 5.0 cm).

[0234] The obtained Sn-plated material was subjected to a reflow soldering treatment (Sn melting treatment). In this reflow soldering treatment, a near-infrared heater (HYW-8N manufactured by HYBEC CORPORATION., rated voltage 100 V, rated power 560 W) was used, and the set current value was set to 10.8 A using a power controller (HYW-20CCR-αN manufactured by HYBEC CORPORATION.), and the Sn-plated material was heated in an air atmosphere for 11 seconds (about 250 °C) to melt the surface of the Sn plating layer, and then immediately immersed in a water bath at 20 °C for cooling.

[0235] For the obtained reflow Sn-plated material, the thickness of the Sn coating film and the coefficient of friction were determined in the same manner as in Example 1, and the micro-sliding wear characteristics and weldability were evaluated.

[0236] [Comparative Example 4] <Ag plating>

[0237] The plating time was changed to 150 seconds, and except for this, the blank was subjected to silver flash plating in the same manner as in Example 1.

[0238] Prepare the same sulfonic acid-based silver plating solution as used in Example 1 (DAINSILVER GPE-HB manufactured by DAIWA CHEMICAL CO., LTD). Using the blank material that has been silver flash-plated as the cathode and a silver electrode plate as the anode, immerse the 5.0 cm long and 5.0 cm wide (the entire surface of the blank material) of the blank material that has been silver flash-plated in the aforementioned sulfonic acid-based silver plating solution, and while stirring at 400 rpm using a stirrer, at a temperature of 25 °C and a current density of 3 A / dm 2 Electroplating was carried out for 120 seconds to obtain a plated material with an Ag coating formed on the blank material. It should be noted that the Ag coating was formed on the entire surface of the surface layer of the blank material (a region 5.0 cm long and 5.0 cm wide).

[0239] For the obtained Ag-plated material, the thickness and friction coefficient of the silver coating film were determined in the same manner as in Example 1, and the micro-sliding wear characteristics and weldability were evaluated.

[0240] The manufacturing conditions of the composite materials, Sn-plated materials, and Ag-plated materials in Examples 1 to 5 and Comparative Examples 1 to 4 above are summarized in Table 1 below, and the various evaluation results are summarized in Table 2 below.

[0241] [Table 1]

[0242]

[0243] [Table 2]

[0244]

[0245] Explanation of Reference Signs

[0246] 10 Composite material

[0247] 12 Blank material

[0248] 14 Metal coating film

[0249] 16 Composite coating film

[0250] 18 Exposed part of the metal coating film

[0251] 20 Exposed part of the composite coating film

[0252] 22 The part between a part of the exposed part of the metal coating film 18 and a part of the exposed part of the composite coating film 20

[0253] 30 Terminal fitting part

[0254] 32 Welding part

[0255] 34 Spacing part

[0256] 36 Blank material

[0257] 38 Metal coating film

[0258] 40 Composite coating film

[0259] 42 Exposed part of metal coating film

[0260] 44 Exposed part of composite coating film

[0261] 50 Housing component

[0262] 60 Terminal

[0263] 70 Female terminal

[0264] 72 Storage part

[0265] 74 Fixing part

[0266] 76 Housing component

Claims

1. A composite material used in the manufacture of a terminal having a welding portion and a terminal fitting portion, which is a composite material formed by forming a metal coating film and a composite coating film on a blank. The metal coating film contains at least one of silver and tin, and the composite coating film is composed of a silver layer containing carbon particles. In the composite material, there are portions where the metal coating film is exposed and portions where the composite coating film is exposed.

2. The composite material according to claim 1, wherein The portion of the composite material where the metal coating film is exposed corresponds to the welding portion of the terminal, and the portion where the composite coating film is exposed corresponds to the terminal fitting portion of the terminal.

3. A method for manufacturing a terminal, which processes the composite material according to claim 1 or 2 into the shape of a terminal.

4. A terminal, which is a terminal having a welding portion and a terminal fitting portion formed by forming a coating film on a blank. The coating film includes a metal coating film and a composite coating film. The metal coating film is formed on the blank and contains at least one of silver and tin, and the composite coating film is formed on the blank and is composed of a silver layer containing carbon particles. The portion of the terminal where the metal coating film is exposed constitutes the welding portion. The portion of the terminal where the composite coating film is exposed constitutes the terminal fitting portion.

5. The terminal according to claim 4, wherein, The terminal is a male terminal that fits with a female terminal having a receiving portion.

6. The terminal according to claim 4 or 5, wherein, The metal coating film is a silver coating film composed of silver formed on the entire surface of the blank surface layer. A part of the silver coating film is formed with the composite coating film.

7. The terminal according to claim 6, wherein, The thickness of the metal coating film is 0.01 - 2.0 μm.

8. The terminal according to claim 4 or 5, wherein, The proportion of carbon particles in the surface of the composite coating film is 1 - 80 area %.

9. The terminal according to claim 4 or 5, wherein The thickness of the composite coating film is 0.5 - 15 μm.

10. The terminal according to claim 4 or 5, wherein, A base layer composed of at least one selected from the group consisting of Cu, Ni, Sn, and Ag is formed on the blank, and the metal coating film and the composite coating film are formed on the base layer.

11. The terminal according to claim 4 or 5, further having a spacer portion that separates the welding portion and the terminal fitting portion.

12. A method for manufacturing a terminal, which includes the following steps: forming a metal coating film and a composite coating film on a blank, and processing the obtained composite material into the shape of a terminal. The metal coating film contains at least one of silver and tin, and the composite coating film is composed of a silver layer containing carbon particles. The portion of the terminal where the metal coating film is exposed constitutes the welding portion. The portion of the terminal where the composite coating film is exposed constitutes the terminal fitting portion.

13. A method for manufacturing a terminal, which includes the following steps: processing a blank into the shape of a terminal, and forming a metal coating film and a composite coating film on the processed blank. The metal coating film contains at least one of silver and tin, and the composite coating film is composed of a silver layer containing carbon particles. The portion of the terminal where the metal coating film is exposed constitutes the welding portion. The portion of the terminal where the composite coating film is exposed constitutes the terminal fitting portion.

14. A method for manufacturing a terminal, which includes the following steps: forming a silver coating film composed of silver on the entire surface of the blank surface layer, forming a composite coating film composed of a silver layer containing carbon particles on a part of the silver coating film, and processing the obtained composite material into the shape of a terminal. The portion of the terminal where the silver coating film is exposed constitutes the welding portion. The portion of the terminal where the composite coating film is exposed constitutes the terminal fitting portion.

15. A method for manufacturing a terminal, comprising the following steps: processing a blank into the shape of a terminal, forming a silver coating film composed of silver on the entire surface of the processed blank, and forming a composite coating film composed of a silver layer containing carbon particles on a part of the silver coating film. The portion of the terminal where the silver coating film is exposed constitutes the welding portion. The portion of the terminal where the composite coating film is exposed constitutes the terminal fitting portion.

16. The manufacturing method of the terminal according to any one of claims 12 to 15, wherein, The terminal is a male terminal that fits with a female terminal having a receiving portion.

17. The method for manufacturing a terminal according to claim 14 or 15, wherein, A part of at least one of a part of the portion where the silver coating film is exposed and a part of the portion where the composite coating film is exposed further constitutes a spacer portion that separates the welding portion and the terminal fitting portion.

18. The method for manufacturing a terminal according to claim 14 or 15, wherein, The thickness of the silver coating film is 0.01 to 2.0 μm.

19. The manufacturing method of the terminal according to claim 14 or 15, wherein, A base layer composed of at least one selected from the group consisting of Cu, Ni, Sn, and Ag is formed on the entire surface of the blank. The silver coating film is formed on the entire surface of the base layer.

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