WO2009116601A1 - Metallic material for connector and process for producing the metallic material for connector - Google Patents

Abstract

Disclosed is a metallic material for a connector, comprising a base material of a bar or a square wire material formed of copper or a copper alloy. In a part of the surface of the metallic material, a striped copper-tin alloy layer is provided in a longitudinal direction of the metallic material. A tin layer or a tin alloy layer is provided on the remaining part of the surface of the metallic material. Also disclosed is a process for producing a metallic material for a connector, providing a bar or a square wire material of copper or a copper alloy as a base material, forming a tin plating layer or a tin alloy plating layer on the base material to prepare an intermediate material, and subjecting the intermediate material to reflow treatment in a stripe form in the longitudinal direction of the intermediate material.

Description

Metal material for connector and manufacturing method thereof

The present invention relates to a metal material for a connector and a manufacturing method thereof, and more particularly, to a metal material for a connector that achieves both low insertion force and connection reliability and a manufacturing method thereof.

A plating material in which a plating layer such as tin (Sn) or tin alloy is provided on a base material of a conductor such as copper (Cu) or a copper alloy (hereinafter referred to as a base material as appropriate) is excellent in the base material. It is known as a high-performance conductor material having electrical conductivity and strength, and excellent electrical connectivity, corrosion resistance, and solderability of the plated layer, and is widely used for various terminals and connectors.

By the way, in recent years, with the progress of electronic control, the mating connector has become multipolar, so a great deal of force is required when inserting and removing the male terminal group and the female terminal group, especially in a narrow space such as in the engine room of an automobile. Since insertion / extraction work is difficult, reduction of the insertion / extraction force is strongly demanded.

As a method of reducing the insertion / extraction force, there is a method in which the Sn plating layer on the surface of the connector terminal is thinned to weaken the contact pressure between the terminals. This method is fretting between the contact surfaces of the terminals because the Sn plating layer is soft. A phenomenon may occur and poor conduction may occur between the terminals.

The fretting phenomenon is that the soft Sn plating layer on the surface of the terminal wears and oxidizes due to fine sliding that occurs between the contact surfaces of the terminal due to vibration, temperature change, etc., and becomes a wear powder having a large specific resistance. When this phenomenon occurs between terminals, a connection failure occurs. This phenomenon is more likely to occur as the contact pressure between the terminals is lower.

In Patent Document 1, a base copper plating layer is formed on a base material of copper or a copper alloy, a tin plating layer is further formed on the surface, and then a surface opposite to the sliding surface in the fitting portion of the terminal By fitting the laser beam onto the sliding surface, the part corresponding to the laser beam spot on the sliding surface is heated by heat transfer, and a copper tin alloy layer is formed at the interface between the tin plating layer and the underlying copper plating layer A method for manufacturing the connection terminal is described.
If the laser irradiation conditions allow the tin plating layer to remain thin, the terminal insertion force can be reduced while maintaining a stable contact resistance, and direct laser irradiation is not performed, so the tin plating layer does not undergo melting changes. It is said that the contact resistance does not deteriorate.

In Patent Document 2, a tab portion surface is formed by elastic contact between a flat tab portion surface of a fitting type male terminal and a protruding portion provided so as to sandwich the tab portion without a fitting portion of a fitting type female terminal. In the tin plating layer applied to the surface of the tab portion of the fitting-type male terminal where the insertion / removal trace is formed, the plating thickness in the vicinity of the connection trace at the end of the insertion / removal trace is thicker than the part where the insertion / removal trace is formed A mating male terminal is described.
This fitting type male terminal has a plating layer that can ensure connection reliability in the contact part where the connection trace will be formed, and the plating layer of the part where the insertion / extraction trace of the front part is formed is thin, It is said that both the insertion force reduction effect and the connection reliability can be achieved.

However, in the above-mentioned fitting type connection terminal, it is still low due to the fact that the solder wettability is reduced by heating from the back side used for soldering, and the friction coefficient of the portion where sliding occurs during insertion is high. Insertion power and connection reliability were not fully compatible.

Japanese Patent Laid-Open No. 11-233228 JP 2005-353352 A

An object of the present invention is to provide a metal material for a connector that has both low insertion force and connection reliability, and a method for manufacturing the same.

According to the present invention, the following means are provided:
(1) In a metal material for a connector using a strip or a square wire formed of copper or a copper alloy as a base material, a part of the surface of the metal material has copper tin in a stripe shape in the longitudinal direction of the metal material An alloy layer is formed, and a metal layer for a connector, wherein a tin layer or a tin alloy layer is formed on the remaining portion of the surface of the metal material,
(2) In the connector metal material in which a strip or a square wire formed of copper or a copper alloy is used as a base material, and a tin layer or a tin alloy layer is formed on the surface of the base material, the tin layer or the tin alloy The thickness of the layer is changed in a stripe shape in the width direction of the metal material, and a copper tin alloy layer is formed at least in a lower layer of a region where the thickness of the tin layer or the tin alloy layer is thin. Metal materials for connectors,
(3) The metal material for a connector according to (1) or (2), wherein a copper layer or a copper alloy layer is formed below the tin layer or the tin alloy layer,
(4) The connector metal material according to any one of (1) to (3), wherein a nickel layer or a nickel alloy layer is formed on the base material.
(5) A copper or copper alloy strip or square wire is used as a base material, a tin plating layer or a tin alloy plating layer is formed on the base material to obtain an intermediate material, and then striped in the longitudinal direction of the intermediate material A method for producing a metal material for a connector, characterized by performing a reflow treatment in a shape,
(6) The method for producing a metal material for a connector according to (5), wherein the reflow treatment is performed and the copper tin alloy is exposed to a part of the surface.
(7) The method for producing a metal material for a connector according to (6), wherein the thickness of the tin plating layer or the tin alloy plating layer before the reflow treatment is 0.3 to 0.8 μm,
(8) A copper plating layer or a copper alloy plating layer is provided between the base material and the tin plating layer or the tin alloy plating layer, or a nickel plating layer or a nickel alloy from the side close to the base material A method for producing a metal material for a connector according to (6), wherein an intermediate material is obtained by providing a plating layer, a copper plating layer or a copper alloy plating layer;
(9) The tin plating layer or tin alloy plating layer before the reflow treatment has a thickness of 0.3 to 0.8 μm, and the tin plating or tin alloy with respect to the thickness of the copper plating layer (Cu thickness) The method for producing a metal material for a connector according to item (8), wherein the ratio (Sn thickness / Cu thickness) of the thickness (Sn thickness) of the plating layer is less than 2;
(10) The method for producing a metal material for a connector according to (5), wherein the reflow treatment is performed to form a copper tin alloy layer to reduce the thickness of the tin plating layer or the tin alloy plating layer. ,
(11) The method for producing a metal material for a connector according to (10), wherein a thickness of the tin plating layer or the tin alloy plating layer before the reflow treatment is 0.8 to 1.2 μm,
(12) A copper plating layer or a copper alloy plating layer is provided between the base material and the tin plating layer or the tin alloy plating layer, or a nickel plating layer or a nickel alloy from the side close to the base material The method for producing a metal material for a connector according to (10), wherein an intermediate material is obtained by providing a plating layer, a copper plating layer or a copper alloy plating layer;
(13) The tin plating or tin alloy has a thickness of 0.8 to 1.2 μm before the reflow treatment and the thickness of the copper plating layer (Cu thickness). The ratio (Sn thickness / Cu thickness) of the thickness of the plating layer (Sn thickness / Cu thickness) is 2 or more, and (14) the method for producing a connector metal material according to item (12), The method for producing a metal material for a connector according to any one of (5) to (13), wherein the method is performed by laser irradiation.
Hereinafter, the metal material for connectors according to the above item (1), (3) to (4) {provided directly or indirectly depending on the item (1)}, and the item (5), (6) to (9), (14) {however, the manufacturing method for a connector metal material according to (5), (6) directly or indirectly depending on the above}) Also referred to as the first embodiment of the present invention.
Also, the connector metal material according to item (2), (3) to (4) {provided directly or indirectly subordinate to item (2)}, and item (5) , (10) to (13), (14) {however, limited to those directly or indirectly dependent on (5), (10)}, Are collectively referred to as a second embodiment of the present invention.
Here, unless otherwise specified, the present invention is meant to include all of the first and second embodiments.

The metal material for a connector of the present invention in which a tin or tin alloy plating layer and a copper tin alloy layer appear in the width direction of a strip material (including a plate material) or a square wire material (including a square bar material) is tin or a tin alloy. Compared to the case where only the plating layer is exposed, the friction coefficient can be reduced. Moreover, the metal material for a connector of the present invention in which a thick layer and a thin layer of tin or tin alloy plating appear in the width direction of the strip or the square wire can reduce the friction coefficient as compared with the case of only the thick layer. . When this copper tin alloy layer part or this tin-plated thin layer part is used as a contact, it has a low coefficient of friction and excellent fretting resistance, and the other parts have excellent solderability and environmental resistance. A connector that is excellent and has both low insertion force and connection reliability can be formed.
In addition, the method for manufacturing a metal material for a connector according to the present invention obtains an intermediate material obtained by plating a base material, and performs a reflow treatment in a striped shape in the longitudinal direction. It is possible to obtain a metal material for a connector that satisfies both reliability.

The above and other features and advantages of the present invention will become more apparent from the following description with reference to the accompanying drawings as appropriate.

It is an expansion schematic sectional drawing of the metal material for connectors (square wire) of Example 1. FIG. It is the expansion schematic sectional drawing which expanded further the surface part of the metal material for connectors (square wire) shown in FIG. It is an expansion schematic sectional drawing of the metal material for connectors (square wire) of Example 3. FIG. It is the expansion schematic sectional drawing which expanded further the surface part of the metal material for connectors (square wire) shown in FIG. 5 is an enlarged schematic cross-sectional view of a square wire of Comparative Example 1. FIG. It is the expansion schematic sectional drawing which expanded further the surface part of the square wire shown in FIG. It is an expansion schematic sectional drawing of the square wire of the comparative example 2. It is the expansion schematic sectional drawing which expanded further the surface part of the square wire shown in FIG. It is an expansion schematic sectional drawing of the metal material for connectors (square wire) of Example 8. FIG. It is the expansion schematic sectional drawing which expanded further the surface part of the metal material for connectors (square wire) shown in FIG. It is an expansion schematic sectional drawing of the metal material for connectors (square wire) of Example 10. FIG. It is the expansion schematic sectional drawing which expanded further the surface part of the metal material for connectors (square wire) shown in FIG. It is an expansion schematic sectional drawing of the square wire of the comparative example 3. It is the expansion schematic sectional drawing which expanded further the surface part of the square wire shown in FIG. It is an expansion schematic sectional drawing of the square wire of the comparative example 4. It is the expansion schematic sectional drawing which expanded further the surface part of the square wire shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base material and copper plating layer 1a Base material 1b Copper plating layer 2 Tin plating layer 3 Copper tin alloy layer 4 Nickel plating layer 11 Base material and nickel plating layer 11a Base material 11b Copper plating layer 11c Nickel plating layer 12 Tin plating layer 13 Copper tin alloy layer

The metal material for a connector according to one preferred embodiment of the present invention (the “first embodiment”) is a surface of a metal material for a connector having a strip or a square wire formed of copper or a copper alloy as a base material. In part, a copper tin alloy layer is formed in a stripe shape in the longitudinal direction of the metal material, and a tin layer or a tin alloy layer is formed on the remaining portion of the surface of the metal material.

The metal material for connectors according to another preferred embodiment of the present invention (the “second embodiment”) has a strip or a square wire formed of copper or a copper alloy as a base material, and tin is formed on the surface of the base material. In the connector metal material in which the layer or the tin alloy layer is formed, the thickness of the tin layer or the tin alloy layer changes in a stripe shape in the width direction (short direction) of the metal material, and at least the tin The copper tin alloy layer is formed in the lower layer of the area | region where the thickness of a layer or a tin alloy layer is thin.

As a base material of the metal material for a connector of the present invention, copper or a copper alloy is used, and copper, phosphor bronze, brass, white, beryllium copper having electrical conductivity, mechanical strength and heat resistance required for the connector, Copper alloys such as Corson alloy are preferred.
The shape of the base material is preferably a strip material (including a plate material) or a square wire material (including a square bar material), and more preferably a square wire material. The square wire may have a cross-sectional shape that may be any of a square, a rectangle, and a regular hexagon, and may be a deformed wire. A square wire having a substantially square cross-sectional shape can be preferably used in the present invention.

In the present invention, it is preferable to perform Cu undercoating on the square wire material and provide a Cu plating layer, but there may be no undercoating as long as a copper tin alloy can be formed by reflow described later. By providing the Cu plating layer, it is possible to easily form a Cu—Sn alloy layer with a reduced Cu concentration. The thickness of the Cu plating layer is preferably 0.01 to 3.0 μm. Furthermore, 0.05 to 1.0 μm is preferable.

Further, in order to improve heat resistance, nickel (Ni) base plating having a barrier property for preventing metal diffusion from the lower layer may be applied between the base material and the copper base to provide a nickel plating layer. Nickel base plating is Ni-P, Ni-Sn, Co-P, Ni-Co, Ni-Co-P, Ni-Cu, Ni-Cr, Ni-Zn, Ni-Fe Ni alloy plating may be used. Ni and Ni alloys do not deteriorate even when the barrier function is in a high temperature environment.
When the thickness of the nickel plating layer is less than 0.02 μm, the barrier function is not sufficiently exhibited. When the thickness exceeds 3.0 μm, the plating strain increases and the nickel plating layer is easily peeled off from the base material. Therefore, 0.02 to 3.0 μm is preferable. The upper limit of the thickness of the nickel plating layer is preferably 1.5 μm, more preferably 1.0 μm, considering the terminal processability.

In the present invention, the surface layer of the material is tin-plated or tin-alloy plated, but the tin-plated or tin-alloy plated is preferably matte rather than glossy because it increases the laser absorption rate.
Further, if the tin plating or tin alloy plating thickness is too thin, the heat resistance and environmental resistance of tin are difficult to be exhibited. Therefore, the thickness is preferably 0.3 μm or more in the metal material of the first embodiment, and 0 More preferably, it is 3 to 0.8 μm, and more preferably 0.3 to 0.6 μm. In the metal material of the second embodiment, 0.3 μm or more is preferable, 0.8 to 1.2 μm is more preferable, and 0.8 to 1.0 μm is more preferable.
In the present invention, tin plating may be formed by electroless plating, but is preferably formed by electroplating. As the Sn alloy plating, it is preferable to use Sn-based alloy plating such as Sn—Cu, Sn—Bi, Sn—Ag, Sn—Zn, Sn—In, Sn—Pb and Sn—Ag—Cu. it can.
For the surface Sn plating, for example, a tin sulfate bath is used, the plating temperature is 30 ° C. or less, and the current density is 5 A / dm ² . However, the conditions are not limited to this, and can be set as appropriate.

In the production of the metal material of the first embodiment, when the base copper plating is applied, the ratio of the thickness of the surface tin plating or tin alloy plating layer (Sn thickness) to the thickness of the base copper plating layer (Cu thickness) ( (Sn thickness / Cu thickness) is preferably less than 2, and more preferably 1.0 or more and less than 2.0.
Further, in the production of the metal material of the second embodiment, when the base copper plating is performed, the thickness of the surface tin plating or tin alloy plating layer (Sn thickness) with respect to the thickness of the base copper plating layer (Cu thickness) The ratio (Sn thickness / Cu thickness) is preferably 2 or more, more preferably 2.0 to 3.0.

The metal material for a connector of the present invention is subjected to striped reflow treatment in the longitudinal direction of a strip or a square wire having a tin plating or tin alloy plating layer formed on the outermost layer by the above plating. In addition, in this invention, stripe form means what targets the continuous area | region thinner than the width | variety of the surface in one surface of a strip or a square wire. The reflow process is not limited as long as it is narrower than the width of one surface of the strip or the square wire and can be limitedly reflowed. For example, a process by laser irradiation can be suitably used. The treatment by laser irradiation is preferable in that the portion irradiated with the laser is reflowed in a limited manner. This treatment can be performed, for example, by heating in a stripe shape using a YAG laser irradiation device or a semiconductor laser irradiation device used in material processing.
In the production of the metal material of the first embodiment, the reflow stripe is formed by this treatment, and the copper tin alloy is exposed on a part of the surface of the strip or the square wire. The ratio of the area occupied by the exposed copper-tin alloy on the surface of the material is preferably 20 to 80% when the material is a square wire.
In the production of the metal material of the second embodiment, reflow stripes are formed by this treatment, and the thickness of the tin layer or tin alloy layer changes in a stripe shape in the width direction (short direction) of the metal material. The copper tin alloy layer is formed in the lower layer of the region where the thickness of at least the tin layer or tin alloy layer is thin.

In the present invention, for example, in the case of a square line, the above reflow processing may be performed on at least one surface, but when processed into the shape of a connector, the surface subjected to the reflow processing is changed to a sliding surface (connector to be connected). Contact surface).
The number of reflow stripes is 1 or more, preferably 4 to 8. Further, the number of reflow stripes per surface of the strips and square wires used is preferably 1 to 2. However, the reflow stripe is usually not provided on the end face of the square material.

Hereinafter, reflow processing using laser irradiation will be described.
The laser irradiation conditions are such that the CuSn alloy is exposed to the surface when the metal material of the first embodiment is manufactured. In addition, the metal material of the second embodiment is manufactured under laser irradiation conditions such that a thin Sn plating or Sn alloy plating layer remains on the surface, and the thinnest portion of the Sn plating or Sn alloy plating layer on the surface The thickness is preferably 0.1 to 0.3 μm. In the present invention, the laser output is preferably 1 W to 60 W.
In the present invention, the beam diameter (spot diameter) of the laser is preferably smaller than the width of the strip used, the diameter of the wire, or one side, and larger than 1/5 of the width of the strip, the diameter of the wire, or one side. More preferably, the laser beam diameter is 1/5 to 4/5 in total with respect to the width of the strip or the diameter of the wire and one side.

The depth reflowed by the laser irradiation is adjusted to be shallower than the total plating thickness applied to the material and deeper than the tin plating thickness when the base plating layer is provided.
In order to prevent excessive reflow, the laser irradiation may be performed while cooling the material from the side opposite to the laser irradiation side.
The laser treatment may be performed in the air, but may be performed in a reducing atmosphere.

The connector material of the present invention can be processed into various electrical and electronic connectors including, for example, fitting connectors for automobiles and contacts, by conventional methods. And if the copper tin alloy layer exposed on the surface is used for the contact position in the mated state, it has a low coefficient of friction and excellent fretting resistance, and the other parts are solderable and environmental resistant. A connector that is excellent and has both low insertion force and connection reliability can be formed.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited thereto.
In the following examples and comparative examples, copper plating was performed using a sulfuric acid bath, nickel plating was performed using a sulfamic acid bath, and tin plating was performed using a sulfuric acid bath.

Example 1
After applying a copper base plating of 0.3 μm in thickness to a 7/3 brass square wire having a width of 0.64 mm (Furukawa Electric Co., Ltd., material is JIS standard C2600: the same applies below), the thickness is 0.3 μm. Tin plating was performed. Thereafter, a YAG laser (output 30 W, wavelength 1064 nm) having a beam diameter of 0.2 mm is irradiated in the longitudinal direction of the material at the center in the width direction of each material to reflow, and the rectangular wire shown in the enlarged schematic sectional view of FIG. Got. In FIG. 1, 1 is a base material (brass square wire) and a copper plating layer, 2 is a tin plating layer, and 3 is a copper tin alloy layer. The copper tin alloy layer 3 was exposed on the surface of the laser irradiated portion.
FIG. 2 is an enlarged schematic cross-sectional view schematically showing the surface portion including the copper-tin alloy layer of the rectangular wire shown in FIG. 1 further enlarged. In the figure, 1a is a base material, 1b is a copper plating layer, 2 is a tin plating layer, and 3 is a copper tin alloy layer.

Example 2
After applying a copper base plating to the square wire of a 0.64 mm wide Corson alloy (Furukawa Electric Co., Ltd., trade name EFTEC-97: the same below) to a thickness of 0.5 μm, tin 0.6 μm in thickness Plating was performed. Thereafter, a YAG laser (output 30 W, wavelength 1064 nm) having a beam diameter of 0.2 mm was irradiated in the longitudinal direction of the material at the center of each surface width direction of the material and reflowed to obtain a square wire. The copper tin alloy layer was exposed on the surface of the laser irradiated portion.

Example 3
A nickel base plating of 0.5 μm thickness and a copper base plating thickness of 0.3 μm were applied to a 7/3 brass square wire having a width of 0.64 mm, and then tin plating of a thickness of 0.3 μm was performed. Thereafter, a YAG laser (output: 30 W, wavelength: 1064 nm) having a beam diameter of 0.2 mm is irradiated in the longitudinal direction of the material at the center of each surface width direction of the material to reflow, and the rectangular wire shown in the enlarged schematic sectional view of FIG. Got. In FIG. 3, 1 is a base material (brass square wire) and a copper plating layer, 2 is a tin plating layer, and 3 is a copper tin alloy layer. The copper tin alloy layer was exposed on the surface of the laser irradiated portion.
FIG. 4 is an enlarged schematic cross-sectional view schematically showing the surface portion including the copper tin alloy layer of the rectangular wire shown in FIG. 3 in a further enlarged manner. Although not shown in FIG. 3, the nickel plating layer 4 exists between the base material 1a and the copper plating layer 1b as shown in FIG.

Example 4
A Corson alloy square wire having a width of 0.64 mm was nickel-plated with a thickness of 0.5 μm and copper with a thickness of 0.5 μm, and then tin-plated with a thickness of 0.6 μm. Thereafter, a YAG laser (output 30 W, wavelength 1064 nm) having a beam diameter of 0.2 mm was irradiated in the longitudinal direction of the material at the center of each surface width direction of the material and reflowed to obtain a square wire. The copper tin alloy layer was exposed on the surface of the laser irradiated portion.

Example 5
A nickel base plating of 0.3 μm thickness and a copper base plating thickness of 0.3 μm were applied to a 7/3 brass square wire having a width of 0.64 mm, and then tin plating of 0.3 μm thickness was performed. Thereafter, a semiconductor laser (output 5 W, wavelength 915 nm) adjusted so that the beam diameter is 1/3 of the wire diameter is irradiated in the center of each material in the width direction of the material in the longitudinal direction of the material to obtain a square wire. It was. The copper tin alloy layer was exposed on the surface of the laser irradiated portion.

Example 6
A Corson alloy square wire having a width of 0.64 mm was subjected to nickel base plating with a thickness of 0.3 μm and copper base plating with a thickness of 0.5 μm, and then tin plating with a thickness of 0.6 μm. Thereafter, a semiconductor laser (output 5 W, wavelength 915 nm) adjusted so that the beam diameter is 1/3 of the wire diameter is irradiated in the center of each material in the width direction of the material in the longitudinal direction of the material to obtain a square wire. It was. The copper tin alloy layer was exposed on the surface of the laser irradiated portion.

Example 7
A nickel base plating of 0.5 μm thickness and a copper base plating thickness of 0.3 μm were applied to a 7/3 brass square wire having a width of 0.64 mm, and then tin plating of a thickness of 0.3 μm was performed. Thereafter, a semiconductor laser (output: 5 W, wavelength: 915 nm) with a beam diameter of 0.10 mm was irradiated in the longitudinal direction of the material at the center of each surface width direction of the material and reflowed to obtain a square wire. The copper tin alloy layer was exposed on the surface of the laser irradiated portion.

Comparative Example 1
After applying a nickel base plating of 0.5 μm in thickness to a 7/3 brass square wire having a width of 0.64 mm and a copper base plating of 0.3 μm in thickness, tin plating with a thickness of 0.3 μm was performed. The square wire shown in the enlarged schematic sectional view of was obtained. In FIG. 5, 11 is a base material (brass square wire) and a base plating layer, and 12 is a tin plating layer.
FIG. 6 is an enlarged schematic cross-sectional view schematically showing the surface portion of the rectangular wire shown in FIG. 5 further enlarged. In the figure, 11a is a base material, 11b is a copper plating layer, 11c is a nickel plating layer, and 12 is a tin plating layer.

Comparative Example 2
A nickel base plating of 0.5 μm thickness and a copper base plating thickness of 0.3 μm were applied to a 7/3 brass square wire having a width of 0.64 mm, and then tin plating of a thickness of 0.3 μm was performed. Then, it heated above the melting | fusing point of Sn with the burner and reflowed, and the square wire shown in the enlarged schematic sectional drawing of FIG. 7 was obtained. In FIG. 7, 11 is a base material (brass square wire) and a base plating layer, and 13 is a copper tin alloy layer.
FIG. 8 is an enlarged schematic cross-sectional view schematically showing a further enlarged surface portion of the rectangular wire shown in FIG. In the figure, 11a is a base material, 11c is a nickel plating layer, and 13 is a copper tin alloy layer.

Example 8
After a copper base plating of 0.3 μm was applied to a 7/3 brass square wire having a width of 0.64 mm, tin plating of 0.8 μm was performed. Thereafter, a YAG laser (output 30 W, wavelength 1064 nm) having a beam diameter of 0.2 mm is irradiated in the longitudinal direction of the material at the center of each surface width direction of the material to reflow, and the rectangular wire shown in the enlarged schematic sectional view of FIG. Got. In FIG. 9, 1 is a base material (brass square wire) and a copper plating layer, 2 is a tin plating layer, and 3 is a copper tin alloy layer. The tin-plated layer 2 of the laser-irradiated portion remained on the surface in a state where the thickness was reduced compared with other portions, and the copper-tin alloy layer 3 was formed below the tin-plated layer 2.
FIG. 10 is an enlarged schematic cross-sectional view schematically showing the surface portion including the copper-tin alloy layer of the rectangular wire shown in FIG. 9 further enlarged. In FIG. 10, 1a is a base material, 1b is a copper plating layer, 2 is a tin plating layer, and 3 is a copper tin alloy layer.

Example 9
After applying 0.5 μm of copper base plating to a square wire of a Corson alloy having a width of 0.64 mm, tin plating of 1.2 μm was performed. Thereafter, a YAG laser (output 30 W, wavelength 1064 nm) having a beam diameter of 0.2 mm was irradiated in the longitudinal direction of the material at the center of each surface width direction of the material and reflowed to obtain a square wire. A thin tin plating layer remained on the surface of the laser irradiated portion.

Example 10
A nickel base plating of 0.5 μm and a copper base plating of 0.3 μm were applied to a 7/3 brass square wire having a width of 0.64 mm, followed by 0.8 μm of tin plating. Thereafter, a YAG laser (output 30 W, wavelength 1064 nm) having a beam diameter of 0.2 mm is irradiated in the longitudinal direction of the material at the center of each surface width direction of the material to reflow, and the rectangular wire shown in the enlarged schematic sectional view of FIG. Got. In FIG. 11, 1 is a base material (brass square wire) and a copper plating layer, 2 is a tin plating layer, and 3 is a copper tin alloy layer. The tin-plated layer 2 of the laser-irradiated portion remained on the surface in a state where the thickness was reduced compared with other portions, and the copper-tin alloy layer 3 was formed below the tin-plated layer 2.
FIG. 12 is an enlarged schematic cross-sectional view schematically showing the surface portion including the copper-tin alloy layer of the rectangular wire shown in FIG. 11 further enlarged. Although not shown in FIG. 11, the nickel plating layer 4 exists between the base material 1a and the copper plating layer 1b as shown in FIG.

Example 11
After applying a nickel base plating of 0.5 μm and a copper base plating of 0.5 μm to a Corson alloy square wire having a width of 0.64 mm, a tin plating of 1.2 μm was performed. Thereafter, a YAG laser (output 30 W, wavelength 1064 nm) having a beam diameter of 0.2 mm was irradiated in the longitudinal direction of the material at the center of each surface width direction of the material and reflowed to obtain a square wire. A thin tin plating layer remained on the surface of the laser irradiated portion.

Example 12
A nickel base plating of 0.3 μm and a copper base plating of 0.3 μm were applied to a 7/3 brass square wire having a width of 0.64 mm, and then tin plating of 0.8 μm was performed. Thereafter, a semiconductor laser (output: 5 W, wavelength: 915 nm) adjusted so that the beam diameter is 1/3 of the wire diameter was irradiated in the center of each surface width direction of the material in the longitudinal direction of the material to obtain a square wire. . A thin tin plating layer remained on the surface of the laser irradiated portion.

Example 13
After applying a nickel base plating of 0.3 μm and a copper base plating of 0.5 μm to a Corson alloy square wire having a width of 0.64 mm, a tin plating of 1.2 μm was performed. Thereafter, a semiconductor laser (output: 5 W, wavelength: 915 nm) adjusted so that the beam diameter is 1/3 of the wire diameter was irradiated in the center of each surface width direction of the material in the longitudinal direction of the material to obtain a square wire. . A thin tin plating layer remained on the surface of the laser irradiated portion.

Example 14
A nickel base plating of 0.5 μm and a copper base plating of 0.3 μm were applied to a 7/3 brass square wire having a width of 0.64 mm, followed by 0.8 μm of tin plating. Thereafter, a semiconductor laser having a beam diameter of 0.10 mm (output 5 W, wavelength 915 nm) was irradiated in the longitudinal direction of the material at the center of each surface width direction of the material and reflowed to obtain a square wire. A thin tin plating layer remained on the surface of the laser irradiated portion.

Comparative Example 3
A 7/3 brass square wire having a width of 0.64 mm was subjected to 0.5 μm of nickel base plating and 0.3 μm of copper base plating, and then tin plating of 0.8 μm to obtain a square wire. The square wire shown in the enlarged schematic sectional view of FIG. 13 was obtained. In FIG. 13, 11 is a base material (brass square wire) and a base plating layer, and 12 is a tin plating layer.
FIG. 14 is an enlarged schematic cross-sectional view schematically showing the surface portion of the rectangular wire shown in FIG. 13 further enlarged. In the figure, 11a is a base material, 11b is a copper plating layer, 11c is a nickel plating layer, and 13 is a tin plating layer.

Comparative Example 4
A nickel base plating of 0.5 μm and a copper base plating of 0.3 μm were applied to a 7/3 brass square wire having a width of 0.64 mm, followed by 0.8 μm of tin plating. Then, it heated above the melting | fusing point of Sn with the burner and reflowed, and the square wire shown in the enlarged schematic sectional drawing of FIG. 15 was obtained. In FIG. 15, 11 is a base material (brass square wire) and a base plating layer, 12 is a tin plating layer, and 13 is a copper tin alloy layer. A thin tin plating layer 22 covers the entire surface.
FIG. 16 is an enlarged schematic cross-sectional view schematically showing the surface portion of the rectangular wire shown in FIG. 15 further enlarged. In the figure, 11a is a base material, 11c is a nickel plating layer, 12 is a tin plating layer, and 13 is a copper tin alloy layer.

Test Example An evaluation test was performed on the contact resistance, solder wettability, and dynamic friction coefficient of the square wires of Examples 1 to 14 and Comparative Examples 1 to 4.
(Contact resistance)
The contact resistance was measured by the 4-terminal method, and the contact was measured by applying a 1N load using an Ag probe.
A value of 2 mΩ or less was good, a value of 5 mΩ or less was acceptable, and a value exceeding that was unacceptable.
(Solder wettability)
Solder wettability was measured by the meniscograph method.
The apparatus used was a Solder Checker SAT-5100 manufactured by Reska Co., Ltd.
The solder used was Sn-3.0Ag-0.5Cu lead-free solder, and 25% rosin flux was used.
The judgment criteria are good when 95% or more of the immersion area is wet, pass ○ when 90% or more of the immersion area is wet, and fail X when the immersion area is wet.
(Dynamic friction coefficient)
A Bowden tester was used to measure the dynamic friction coefficient.
The slider was measured with a dimple simulating a female terminal.
As the judgment criteria, μk <0.25 was good ◎, μk <0.3 was acceptable ○, and more than that was unacceptable ×.

As shown in Tables 1 and 2, in Comparative Examples 1 to 4, at least one of contact resistance, solder wettability, and dynamic friction coefficient was rejected, whereas in Examples 1 to 14, all were contact resistance, All of the solder wettability and the dynamic friction coefficient satisfied the acceptance criteria, and were suitable as a connector metal material.

While this invention has been described in conjunction with its embodiments, we do not intend to limit our invention in any detail of the description unless otherwise specified and are contrary to the spirit and scope of the invention as set forth in the appended claims. I think it should be interpreted widely.

This application claims priority based on Japanese Patent Application No. 2008-072545 filed in Japan on March 19, 2008, and Japanese Patent Application No. 2008-072546 filed on March 19, 2008 in Japan. All of which are hereby incorporated by reference as if fully set forth herein.

Claims (14)

In a metal material for a connector using a strip or a square wire formed of copper or a copper alloy as a base material, a copper tin alloy layer is formed in a stripe shape in a longitudinal direction of the metal material on a part of the surface of the metal material. A connector metal material, wherein a tin layer or a tin alloy layer is formed on the remainder of the surface of the metal material. In a metal material for a connector in which a strip or a square wire formed of copper or a copper alloy is used as a base material, and a tin layer or a tin alloy layer is formed on the surface of the base material, the thickness of the tin layer or the tin alloy layer For a connector, wherein a thickness of the metal material is changed in a stripe shape, and a copper tin alloy layer is formed at least in a lower layer of a region where the thickness of the tin layer or tin alloy layer is thin Metal material. 3. The connector metal material according to claim 1, wherein a copper layer or a copper alloy layer is formed under the tin layer or the tin alloy layer. The connector metal material according to any one of claims 1 to 3, wherein a nickel layer or a nickel alloy layer is formed on the base material. A copper or copper alloy strip or square wire is used as a base material, and a tin plating layer or tin alloy plating layer is formed on the base material to obtain an intermediate material. The manufacturing method of the metal material for connectors characterized by performing a process. 6. The method for producing a metal material for a connector according to claim 5, wherein the reflow treatment is performed to expose the copper tin alloy on a part of the surface. The method for producing a metal material for a connector according to claim 6, wherein a thickness of the tin plating layer or the tin alloy plating layer before the reflow treatment is 0.3 to 0.8 µm. A copper plating layer or a copper alloy plating layer is provided between the base material and the tin plating layer or the tin alloy plating layer, or from the side close to the base material, a nickel plating layer or a nickel alloy plating layer, The method for producing a metal material for a connector according to claim 6, wherein an intermediate material is obtained by providing a copper plating layer or a copper alloy plating layer. The tin plating layer or tin alloy plating layer before the reflow treatment has a thickness of 0.3 to 0.8 μm, and the tin plating or tin alloy plating layer has a thickness (Cu thickness) of the copper plating layer. 9. The method for producing a metal material for a connector according to claim 8, wherein a ratio of thickness (Sn thickness) (Sn thickness / Cu thickness) is less than 2. 6. The method for producing a metal material for a connector according to claim 5, wherein the reflow treatment is performed to form a copper tin alloy layer to reduce the thickness of the tin plating layer or the tin alloy plating layer. The method for manufacturing a metal material for a connector according to claim 10, wherein the thickness of the tin plating layer or the tin alloy plating layer before the reflow treatment is 0.8 to 1.2 µm. Between the base material and the tin plating layer or the tin alloy plating layer, a copper plating layer or a copper alloy plating layer is provided, or from the side close to the base material, a nickel plating layer or a nickel alloy plating layer, The method for producing a metal material for a connector according to claim 10, wherein an intermediate material is obtained by providing a copper plating layer or a copper alloy plating layer. The tin plating layer or tin alloy plating layer before the reflow treatment has a thickness of 0.8 to 1.2 μm, and the tin plating or tin alloy plating layer has a thickness (Cu thickness) of the copper plating layer. 13. The method for producing a connector metal material according to claim 12, wherein the ratio of thickness (Sn thickness) (Sn thickness / Cu thickness) is 2 or more. The method for producing a connector metal material according to any one of claims 5 to 13, wherein the reflow treatment is performed by laser irradiation.

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