JP2015167099A - Connector terminal and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a connector terminal, easy to manufacture, exhibiting excellent performance and a manufacturing method of the same.SOLUTION: A connector terminal 1 includes: a metal substrate 2 composed of a metal; an Ag-In alloy layer 3 formed on the substrate 2; and a surface Ag layer 4, laminated on the Ag-In alloy layer 3, exposed to a surface 100. The Ag-In alloy layer 3 and the surface Ag layer 4 may be provided at least at a contact part constituting an electric contact with an opponent terminal or also may be provided at the entire surface of the connector terminal 1.

Description

  The present invention relates to a connector terminal and a manufacturing method thereof.

  For example, a connector terminal provided with an Ag (silver) plating layer capable of supplying a larger current than that of a conventional connector terminal is used as a power supply terminal for a high-power motor in a hybrid car or an electric vehicle. Since Ag has a smaller electrical resistance value than Sn (tin) used for general-purpose terminals, it can reduce the amount of heat generated by energization. Moreover, since Ag has a higher melting point than Sn, it has excellent heat resistance. Due to these Ag characteristics, the connector terminal provided with the Ag plating layer is suitable for applications in which a larger current is applied than in the past.

  However, since the Ag plating layer is relatively soft, wear is likely to occur due to sliding with the mating terminal when the connector terminal is inserted or removed. Moreover, the connector terminal provided with the Ag plating layer has a problem that it is difficult to reduce the coefficient of friction when sliding with the counterpart terminal, and the insertion / extraction force required for insertion / extraction increases. As a result of intensive studies, the present inventors have found that the friction coefficient when sliding with the mating terminal can be reduced by forming an Ag—Sn alloy layer harder than pure Ag on the surface of the connector terminal (patent). Reference 1).

  On the other hand, in the field of sliding members, a technique for reducing the friction coefficient by providing an Ag—In alloy obtained by alloying Ag with In (indium) on the surface is known (Patent Documents 2 and 3). . Since the Ag—In alloy is harder than pure Ag, it has excellent wear resistance. Further, by providing a hard Ag—In alloy on the surface, it is possible to reduce the coefficient of friction when inserting / removing the connector terminal, and as a result, the effect of reducing the insertion / extraction force can be expected.

  In addition, since In has a lower melting point than Sn, the heating temperature in the reflow process for alloying with Ag can be reduced. Therefore, by providing an Ag—In alloy on the surface of the connector terminal instead of the Ag—Sn alloy, it can be expected that the temperature of the reflow process is lowered while maintaining the performance equivalent to or higher than that of the Ag—Sn alloy.

JP2013-231228A JP 2009-249648 A Japanese Patent No. 3823197

However, the sliding members described in Patent Document 2 and Patent Document 3 have an Ag—In alloy on the entire surface of the base material. The Ag—In alloy is harder than pure Ag and has a higher electrical resistivity than pure Ag. Therefore, it is difficult for the connector terminal having an Ag—In alloy on the entire surface of the base material to reduce the contact resistance with the counterpart terminal.

  The present invention has been made in view of such a background, and is intended to provide a connector terminal that is easy to manufacture and exhibits excellent performance, and a method for manufacturing the connector terminal.

One aspect of the present invention is a substrate made of a metal,
An Ag-In alloy layer formed on the substrate;
A connector terminal having a surface Ag layer laminated on the Ag—In alloy layer and exposed on the surface.

According to another aspect of the present invention, a surface of a base material made of a metal is subjected to a plurality of plating treatments, a first Ag plating film, an In plating film laminated on the first Ag plating film, and the In plating film Forming a multilayer metal layer including a second Ag plating film laminated on the surface and exposed on the surface;
Reflow treatment for heating the multilayer metal layer is performed to alloy Ag and In contained in the multilayer metal layer, and the Ag—In alloy layer and the Ag—In alloy layer are laminated on the base material. And a step of forming a surface Ag layer exposed on the surface.

  The connector terminal has the Ag—In alloy layer formed on the base material. Since the Ag—In alloy layer is harder than pure Ag, it is possible to suppress wear during insertion and removal of the connector terminal. In addition, the presence of the Ag—In alloy layer can reduce the coefficient of friction when sliding with the counterpart terminal, thereby reducing the insertion / extraction force of the connector terminal.

  The connector terminal is laminated on the Ag—In alloy layer and has a surface Ag layer exposed on the surface. Since the surface Ag layer is softer than the Ag-In alloy layer and has a lower electrical resistivity, the contact resistance with the counterpart terminal can be reduced. Further, since the surface Ag layer is laminated on the Ag—In alloy layer, the load applied to the surface Ag layer by the counterpart terminal is sufficiently supported by the Ag—In alloy layer. As a result, the connector terminal can suppress wear of the surface Ag layer during insertion / extraction.

  As described above, the connector terminal has low contact resistance, a low coefficient of friction, and excellent wear resistance.

  Moreover, according to the manufacturing method of the said connector terminal, the structure mentioned above can be easily formed on the said base material by giving the said reflow process to the said multilayer metal layer. In addition, since In having a lower melting point than Sn is used, the reflow process can be performed at a lower temperature than when Sn is used. Therefore, the connector terminal can be easily manufactured.

The partial sectional view of the connector terminal in an example. The partial cross section figure of the state which laminated | stacked the multilayer metal layer on the base material in an Example. The perspective view of the connector terminal comprised as a male type terminal in an Example. The perspective view of the connector terminal comprised as a female-type terminal in an Example.

  The connector terminal may be configured, for example, as a male terminal having a tab portion inserted into a female terminal, or as a female terminal having a cylindrical body portion into which the tab portion is inserted. Also good. Further, it may be configured as a PCB (Printed Circuit Board) terminal.

  The Ag—In alloy layer and the surface Ag layer may be provided at least on the contact portion constituting the electrical contact with the counterpart terminal, and may be provided on the entire surface of the connector terminal. For example, when the connector terminal is configured as a male terminal, the Ag—In alloy layer and the surface Ag layer may be provided at least on the tab portion. Similarly, when the connector terminal is configured as a female terminal, the Ag-In alloy layer and the surface Ag layer are, for example, an elastic piece portion that presses the tab portion, or the cylindrical body portion. It can be provided on the inner wall surface or the like facing the elastic piece portion.

  The base material can be selected from various conductive metals. Specifically, Cu, Al (aluminum), Fe (iron), or an alloy containing these metals is preferably used as the substrate. These metal materials are excellent not only in electrical conductivity but also in formability and springiness, and can be applied to various types of electrical contacts. As the shape of the substrate, there are various shapes such as a rod shape and a plate shape, and the dimensions such as the thickness can be variously selected according to the application. In general, the thickness is preferably about 0.2 to 2 mm.

  The Ag—In alloy layer is made of an alloy containing Ag and In. In addition to Ag and In, the Ag—In alloy layer may include a metal element diffused from the base material, inevitable impurities, and the like.

  The Ag-In alloy layer may be laminated on the base material, and another metal layer may be formed between the Ag-In alloy layer and the base material. As such a metal layer, for example, a diffusion barrier layer having an action of suppressing diffusion of a metal element from the substrate to the Ag—In alloy layer or the like can be formed. For example, when the base material is made of Cu or a Cu alloy, the diffusion barrier layer can suppress Cu of the base material from diffusing into the Ag—In alloy layer or the like. As a result, it is possible to suppress a decrease in corrosion resistance and a decrease in electrical conductivity due to the diffused Cu. As the diffusion barrier layer, for example, a Ni (nickel) plating film or the like can be used. Moreover, the film thickness of the said diffusion barrier layer can be suitably set normally in the range of 0.5-2.0 micrometers.

  Moreover, you may form the metal layer which has the effect | action which improves the adhesiveness of the said Ag-In alloy layer and the said base material as a metal layer mentioned above.

  The surface Ag layer is substantially composed of pure Ag, and may contain inevitable impurities in addition to Ag.

  The surface Ag layer is preferably thinner than the Ag-In alloy layer. In this case, the friction coefficient at the time of terminal insertion / extraction can be further reduced. When the film thickness of the surface Ag layer is equal to or greater than the film thickness of the Ag-In alloy layer, the effect of reducing the friction coefficient by the Ag-In alloy layer may be insufficient. Further, in this case, there is a possibility that the load at the time of terminal insertion / extraction by the Ag—In alloy layer may be insufficient, and the wear resistance of the connector terminal may be insufficient.

  Moreover, it is preferable that the film thickness of the said surface Ag layer is 1 micrometer or less. In this case, the wear of the surface Ag layer can be further suppressed, and the friction coefficient when sliding with the counterpart terminal can be further reduced. On the other hand, in order to sufficiently obtain the effect of reducing the contact resistance by the surface Ag layer, the film thickness of the surface Ag layer is preferably 0.5 μm or more. Therefore, in order to obtain a good balance between the wear resistance, the effect of reducing the friction coefficient, and the effect of reducing the contact resistance, it is more preferable to control the film thickness of the surface Ag layer in the range of 0.5 to 1 μm.

  Next, a method for manufacturing the connector terminal will be described. In the method for manufacturing a connector terminal, first, the surface of a base material made of metal is subjected to a plurality of plating treatments to form the multilayer metal layer. The multilayer metal layer includes at least a first Ag plating film, an In plating film laminated on the first Ag plating film, and a second Ag plating film laminated on the In plating film and exposed on the surface. It is. Thus, the Ag—In alloy layer can be easily formed by providing the In plating film between the first Ag plating film and the second Ag plating film. Further, the surface Ag layer can be easily formed by exposing the second Ag plating film to the surface.

  The multilayer metal layer may include other metal films in addition to the first Ag plating film, the In plating film, and the second Ag plating film. For example, when the diffusion barrier layer made of Ni is provided between the base material and the Ag—In alloy layer, a Ni plating film may be provided between the base material and the first Ag plating film. .

  In the multilayer metal layer, the second Ag plating film is preferably thicker than the first Ag plating film. The surface Ag layer can be more easily formed by increasing the thickness of the second Ag plating film exposed on the surface.

  After forming the multilayer metal layer, a reflow treatment for heating the multilayer metal layer is performed to alloy Ag and In contained in the multilayer metal layer, and an Ag-In alloy layer on the base material, A step of forming a surface Ag layer laminated on the Ag—In alloy layer and exposed on the surface is performed. In the reflow process, a part of the second Ag plating film is not alloyed with In and becomes the surface Ag layer. Further, the first Ag plating film may be entirely alloyed with In, or a part thereof may remain as pure Ag without being alloyed with In.

  The heating temperature in the reflow process is preferably higher than the melting point of In and lower than the melting point of Ag. That is, by heating in the specific temperature range in the reflow process, only In can be melted. Thereby, the Ag—In alloy layer can be formed more easily.

  Examples of the connector terminal will be described with reference to FIGS. As shown in FIG. 1, the connector terminal 1 is laminated on a base material 2 made of metal, an Ag—In alloy layer 3 formed on the base material 2, and the Ag—In alloy layer 3. And the surface Ag layer 4 exposed to the surface.

  For example, as shown in FIG. 3, the connector terminal 1 may be configured as a male terminal 1 a having a tab portion 11, and as shown in FIG. 4, a cylindrical body portion 12 into which the tab portion 11 is inserted is provided. The female terminal 1b may be configured. Although not shown in the drawing, the connector terminal 1 can be configured as a PCB connector terminal.

  Hereinafter, the detailed structure of the connector terminal 1 is demonstrated with a manufacturing method. First, the surface of the base material 2 made of a Cu alloy is subjected to a plurality of times of plating, and as shown in FIG. 2, the first Ag plating film 51 laminated on the base material 2 and the first Ag plating film 51 are laminated. A multilayer metal layer 5 is formed which is formed of the In plating film 52 and the second Ag plating film 53 which is laminated on the In plating film 52 and exposed on the surface 500. Conventionally known conditions can be adopted as the processing conditions for performing these plating processes and the pretreatment conditions for the substrate 2.

  Next, a reflow process for heating the multilayer metal layer 5 is performed to alloy Ag and In contained in the multilayer metal layer 5. The heating temperature in the reflow process can be set to 150 ° C., for example. The heating time in the reflow process can be set to 120 hours, for example. When the thicknesses of the first Ag plating film 51, the In plating film 52, and the second Ag plating film 53 are set to 1.5 μm, 2.0 μm, and 2.5 μm, respectively, a reflow process is performed using the above-described conditions. Thus, a 5.0 μm Ag—In alloy layer 3 and a 1.0 μm surface Ag layer 4 can be formed on the substrate 2.

  In addition, the film thickness of the plating film mentioned above can be suitably changed based on the following way of thinking, for example. Considering the mass number and density of Ag and In, in order to alloy Ag and In without excess or deficiency, the Ag plating film having a total thickness of 1.5 times the film thickness of the In plating film 52 is necessary. It is considered that the diffusion of In and the alloying of In and Ag by the reflow process proceed at the same speed in the first Ag plating film 51 and the second Ag plating film 53. Therefore, if the first Ag plating film 51 and the second Ag plating film 53 have a film thickness of 0.75 times that of the In plating film 52, Ag and In can be alloyed without excess or deficiency. That is, the 1st Ag plating film 51 should just have a film thickness of 0.75 times the In plating film 52 at least, and when it has a film thickness beyond it, the base material 2 and an Ag-In alloy layer 3 may remain pure Ag.

  On the other hand, the second Ag plating film 53 needs a film thickness for forming the surface Ag layer 4 in addition to the film thickness consumed for alloying with In. Therefore, the second Ag plating film 53 may be a film thickness obtained by adding the target film thickness of the surface Ag layer 4 to the film thickness of 0.75 times that of the In plating film 52. The above concept is an example for setting the film thickness, and the present invention is not limited to this.

DESCRIPTION OF SYMBOLS 1 Connector terminal 2 Base material 3 Ag-In alloy layer 4 Surface Ag layer

Claims (8)

A base material made of metal;
An Ag-In alloy layer formed on the substrate;
A connector terminal having a surface Ag layer laminated on the Ag—In alloy layer and exposed on the surface.   The connector terminal according to claim 1, wherein the surface Ag layer is thinner than the Ag—In alloy layer.   The connector terminal according to claim 1, wherein the surface Ag layer has a thickness of 1 μm or less.   The connector terminal according to claim 1, wherein a diffusion barrier layer is formed between the base material and the Ag—In alloy layer. The surface of the base material made of metal was subjected to a plurality of plating treatments, and the first Ag plating film, the In plating film laminated on the first Ag plating film, and the In plating film were laminated and exposed on the surface. Forming a multilayer metal layer including a second Ag plating film;
Reflow treatment for heating the multilayer metal layer is performed to alloy Ag and In contained in the multilayer metal layer, and the Ag—In alloy layer and the Ag—In alloy layer are laminated on the base material. And a step of forming a surface Ag layer exposed on the surface.   6. The method of manufacturing a connector terminal according to claim 5, wherein the second Ag plating film is thicker than the first Ag plating film.   7. The method of manufacturing a connector terminal according to claim 5, wherein the surface Ag layer has a thickness of 1 μm or less.   The method for manufacturing a connector terminal according to any one of claims 5 to 7, wherein a heating temperature in the reflow treatment is higher than a melting point of In and lower than a melting point of Ag.

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