JP5479766B2 - Metal square wire for connecting parts and manufacturing method thereof - Google Patents

Description

  The present invention relates to a metal material for connecting parts and a method for producing the same.

  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. 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 Cu—Sn alloy coating layer and a Sn coating layer are formed in this order on the surface of a base material made of a Cu plate, and the material surface exposed area ratio of the Cu—Sn alloy coating layer is 3 to 3. 75%, the average thickness is 0.1-3.0 μm, the Cu content is 20-70 at%, and the average thickness of the Sn or Sn alloy coating layer is 0.2-5.0 μm A conductive material for connecting parts is described. It is also described that a Cu-Sn alloy coating layer is formed by performing a reflow process.
When this conductive material is used for a multipolar connector in an automobile or the like, for example, the insertion force when fitting the male and female terminals is low, the assembly work can be performed efficiently, and it can be performed for a long time in a high temperature atmosphere. It is said that electrical reliability (low contact resistance) can be maintained even when held or in a corrosive environment.

JP 2006-77307 A

  However, the conductive material for connecting parts described above is made of a Cu plate, but when the base material is a square wire, in the manufacture of a Cu-Sn alloy plated wire by heat treatment such as reflow treatment. In some cases, the surface properties after the reflow treatment deteriorate. This defect is considered to occur due to the non-uniform distribution of Sn due to the flow of Sn on the rectangular wire during the reflow process. However, in the technique of Patent Document 1, the base material is formed from a Cu plate. Therefore, such a problem as when the base material is a square wire cannot occur.

  Then, an object of this invention is to provide the metal material for connection components with the favorable surface property after heat processing, and the favorable solderability in a post process, and its manufacturing method.

The above-mentioned subject is achieved by the following means. That is, the present invention
(1) A metal rectangular wire for connecting parts, in which a copper or copper alloy square wire is used as a base material, and a copper tin alloy layer substantially composed of copper and tin is formed on the outermost surface thereof. on wood, nickel, cobalt, iron, or have layers of these alloys are formed, the copper-tin alloy layer of the outermost surface further zinc, indium, gallium, lead, cadmium, magnesium, gold, aluminum Containing at least one selected from the group in a total amount of 0.01% to 1% by mass ratio with respect to the content of tin, a square wire for connecting parts,
(2) The thickness of the layer made of nickel, cobalt, iron or an alloy thereof is 0.02 to 3.0 μm , the metal square wire for connecting parts according to (1),
(3) a rectangular wire material of copper or a copper alloy as a base material, nickel on the base metal, cobalt, to form an iron or layers of these alloys, furthermore, zinc, indium, gallium, lead, cadmium, magnesium After forming a tin alloy plating layer containing at least one selected from the group of gold and aluminum in a total amount of 0.01% by mass or more and 1% by mass or less to obtain an intermediate material, the intermediate material is subjected to heat treatment A method for producing a metal square wire for connecting parts, characterized in that an alloy layer containing copper and tin is formed on the outermost surface;
(4) The thickness of the tin alloy plating layer before the heat treatment is 0.3 to 0.8 μm, and the method for producing a metal square wire for connecting parts according to the item (3), and
(5) The method for producing a metal square wire for a connection part according to any one of (3) or (4 ), wherein the heat treatment is a reflow treatment.
Is to provide.

  The metal material for connecting parts of the present invention is substantially composed of copper and tin on the outermost surface of a base material of copper or a copper alloy square wire (including a square bar material), and further includes zinc, indium, antimony, and gallium. , Lead, bismuth, cadmium, magnesium, silver, gold, aluminum containing at least one selected from the group consisting of 0.01% and 1% by mass with respect to the content of tin. It is possible to obtain a metal material that has sufficient gloss after heat treatment and has extremely high pre-solderability and post-plating properties for promoting solder wetting.

It is a partial expansion schematic sectional drawing of the metal material for connection components (square wire) of Example 1. FIG. It is a partial expansion schematic sectional drawing of the metal material (square wire) for connection components of Example 2. FIG. It is a partial expansion schematic sectional drawing of the metal material (square wire) for connection components of Example 3. FIG.

  The metal material for connecting parts according to the present invention is based on a square wire formed of copper or a copper alloy, and is substantially composed of copper and tin on the outermost surface thereof. Furthermore, zinc (Zn), indium (In), At least selected from the group consisting of antimony (Sb), gallium (Ga), lead (Pb), bismuth (Bi), cadmium (Cd), magnesium (Mg), silver (Ag), gold (Au), and aluminum (Al) One type is contained in a total amount of 0.01% or more and 1% or less by mass ratio with respect to the content of tin.

Copper or copper alloy is used as the base material of the metal material for connecting parts of the present invention, and has the conductivity, mechanical strength and heat resistance required for the connector, phosphor bronze, brass, white, beryllium copper Copper alloys such as Corson alloy are preferred.
As the shape of the base material, a rectangular wire material (including a square bar material) is preferable. 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 to provide a Cu plating layer. However, a structure in which a copper tin alloy layer can be formed under the outermost tin alloy plating layer by heat treatment described later. If it is, the base may be omitted. By providing the Cu plating layer, formation of an alloy layer containing Cu and Sn can be facilitated. The thickness of the Cu plating layer is preferably 0.01 to 3.0 μm. Furthermore, 0.05-1.0 micrometer is preferable.

In order to improve heat resistance, nickel (Ni) base plating having a barrier property for preventing metal diffusion from the base material may be applied between the base material and the copper base. 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. In addition to nickel, cobalt (Co), iron (Fe), or alloys thereof exhibit the same effect, and thus are preferably used as an underlayer.
When the thickness of the layer made of nickel, cobalt, iron, or an alloy thereof is less than 0.02 μm, the barrier function is not sufficiently exhibited, and when it exceeds 3.0 μm, the plating distortion increases and the layer is easily peeled off. Therefore, 0.02-3.0 micrometers is preferable. The upper limit of the thickness of the layer made of nickel, cobalt, iron, or an alloy thereof is preferably 1.5 μm, more preferably 1.0 μm, considering the terminal workability.

In the present invention, tin alloy plating is applied to the surface layer of the material. This tin alloy plating contains at least one selected from the group consisting of zinc, indium, antimony, gallium, lead, bismuth, cadmium, magnesium, silver, gold, and aluminum in a total amount of 0.01% by mass to 1% by mass. To do.
In addition, if the tin alloy plating thickness is too thin, the environment resistance of the copper tin alloy layer finally formed on the outermost layer is difficult to be exhibited. Therefore, the thickness is preferably 0.3 μm or more. If the thickness is too thick, tin alloy will eventually remain on the surface of the copper-tin alloy layer and cause fretting phenomenon. Therefore, 0.3 to 0.8 μm is more preferable, and 0.3 to 0.6 μm is preferable. Further preferred.
In the present invention, the tin alloy plating may be formed by electroless plating, but is preferably formed by electroplating. Moreover, as tin alloy plating, Sn-Zn, Sn-In, Sn-Sb, etc., other than the above elements, copper (Cu) other than the above elements may be 0.5. It may be contained by mass% or less (including zero).
For example, a tin sulfate bath may be used for electroplating of the surface layer with a plating temperature of 30 ° C. or less and a current density of 5 A / dm ² . However, the conditions are not limited to this, and can be set as appropriate.

  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 less than 2 Is preferable, and it is more preferable that it is 1.0-2.0.

  The metal material for connecting parts of the present invention is heat-treated in the longitudinal direction of the rectangular wire material in which the tin alloy plating layer is formed on the outermost layer by the above plating. In addition, heat processing will not be limited if it is a method which can heat the said square wire rod uniformly like reflow processing. The treatment by reflow is preferable because the heat treatment time of the square wire can be shortened.

  The metal material for connecting parts of the present invention can be processed into a variety of electrical and electronic connectors, for example, a fitting connector for automobiles and a contact, by a conventional method. The outermost copper-tin alloy layer further includes at least one selected from the group consisting of zinc, indium, antimony, gallium, lead, bismuth, cadmium, magnesium, silver, gold, and aluminum, and the content of the tin in a total amount Since it is contained in a mass ratio of 0.01% or more and 1% or less, it is possible to obtain a metal material for connection parts that has good surface properties after heat treatment and good solderability in the subsequent process.

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 (invention examples) and comparative examples, the conditions were as follows.
Base material: A square wire of a Corson alloy (Furukawa Electric Co., Ltd., EFTEC-97: the same applies below) whose cross-sectional shape is a square with a side of 0.64 mm and whose vertical direction is the longitudinal direction of the square wire. . Hereinafter, the expression “width” may be used for one side of a square line. Two types of surface roughness were used: Ra = 2.0 μm (expressed as Ra = large in the table) and Ra = 0.05 μm (expressed as Ra = small in the table).
Plating: Copper plating was performed using a sulfuric acid bath, nickel plating was performed using a sulfamic acid bath, and tin alloy plating was performed using a sulfuric acid bath. Here, the plating was performed by electroplating.
A liquid containing a proper amount of tin alloy plating and elements added thereto: Zn ion, In ion, and Cu ion was prepared.
Measurement of concentration of additive element in tin plating: Plating was performed on stainless steel, and only the plating film was dissolved in acid, and analyzed by an ICP emission analyzer.
Heat treatment: Reflow treatment was performed by heating on a hot plate.

Example 1
A tin alloy plating with a thickness of 0.5 μm was applied to a square wire of a Corson alloy having a width of 0.64 mm. Thereafter, the material was subjected to a reflow treatment at 350 ° C. for 10 seconds to obtain a rectangular wire shown in the partially enlarged schematic sectional view of FIG. In FIG. 1, a part near the midpoint of one side of the square wire is enlarged (the same applies to the following drawings). In FIG. 1, 1 indicates a base material, and 2 indicates a copper-tin alloy layer.

Comparative Example 1
A tin alloy plating with a thickness of 0.5 μm was applied to a square wire of a Corson alloy having a width of 0.64 mm. The amount of additive element in the tin alloy plating did not fall within the scope of the examples. Thereafter, the material was subjected to a reflow treatment at 350 ° C. for 10 seconds to obtain a rectangular wire shown in the partially enlarged schematic sectional view of FIG.

Example 2
After applying a copper plating having a thickness of 0.3 μm to a square wire of a Corson alloy having a width of 0.64 mm, a tin alloy plating having a thickness of 0.5 μm was performed. Thereafter, the material was subjected to a reflow treatment at 500 ° C. for 5 seconds to obtain a rectangular wire shown in the partially enlarged schematic cross-sectional view of FIG. In FIG. 2, 1 indicates a base material, and 2 indicates a copper-tin alloy layer. The copper plating layer was all converted to the copper tin alloy layer 2 by reacting with the outermost tin alloy plating by the reflow treatment.

Comparative Example 2
After a copper plating with a thickness of 0.3 μm was applied to a square wire of a Corson alloy having a width of 0.64 mm, a tin alloy plating with a thickness of 0.5 μm was performed. The amount of additive element in the tin alloy plating did not fall within the scope of the examples. Thereafter, the material was subjected to a reflow treatment at 350 ° C. for 10 seconds to obtain a rectangular wire shown in the partially enlarged schematic sectional view of FIG. The copper plating layer was all converted to the copper tin alloy layer 2 by reacting with the outermost tin alloy plating by the reflow treatment.

Example 3
After applying a nickel plating with a thickness of 0.4 μm to a square wire of a Corson alloy having a width of 0.64 mm, a copper plating with a thickness of 0.3 μm was applied, and then a tin alloy plating with a thickness of 0.5 μm was performed. Thereafter, the material was subjected to a reflow treatment at 500 ° C. for 5 seconds to obtain a rectangular wire shown in the partially enlarged schematic sectional view of FIG. In FIG. 3, 1 is a base material, 2 is a copper tin alloy layer, and 3 is a nickel layer. The copper plating layer was all converted to the copper tin alloy layer 2 by reacting with the outermost tin alloy plating by the reflow treatment.

Comparative Example 3
After applying a nickel plating with a thickness of 0.4 μm to a square wire of a Corson alloy having a width of 0.64 mm, a copper plating with a thickness of 0.3 μm was applied, and then a tin alloy plating with a thickness of 0.5 μm was performed. The amount of additive element in the tin alloy plating did not fall within the scope of the examples. Thereafter, the material was subjected to a reflow treatment at 350 ° C. for 10 seconds to obtain a rectangular wire shown in the partially enlarged schematic sectional view of FIG. The copper plating layer was all converted to the copper tin alloy layer 2 by reacting with the outermost tin alloy plating by the reflow treatment.

Test Example An evaluation test was performed on the contact resistance, solder wettability, and surface gloss of the square wires of Examples 1 to 3 and Comparative Examples 1 to 3. These results are shown in Tables 1-1 and -2 for Example 1 and Comparative Example 1, in Tables 2-1 and 2-2 for Example 2 and Comparative Example 2, and in Example 3 and Comparative Example 3. Are shown in Tables 3-1 to 3-2, respectively.
(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.
Judged as good within 2 mΩ, indicated by “◎” in the table, judged as acceptable within 5 mΩ, indicated by “◯” in the table, and judged as unacceptable when exceeding 5 mΩ. Indicated by "x".
(Solder wettability)
Solder wettability was measured by the meniscograph method.
The apparatus used was a Solder Checker SAT-5100 manufactured by Reska Co., Ltd.
After applying a flux composed of 25% rosin and the remaining isopropyl alcohol on the surface of the square wire, it was immersed in a lead-free solder bath of Sn-3.0Ag-0.5Cu held at 260 ° C. and held for 3 seconds Raised.
Judgment criteria are determined to be good when 95% or more of the immersion area is wet and indicated as “◎” in the table, and determined to be acceptable when 90% or more of the immersion area is wet. In the table | surface, it showed with "(circle)" and the case where wetting was less than 90% of immersion area was determined to be disqualified, and it showed with "x" in the table | surface.
(Surface gloss)
The surface gloss was visually inspected. Judged that the product has a uniform and uniform glossiness is good and is indicated by “◎” in the table. The product has a slight dullness but has a sufficient glossiness as a product. In the table, it was indicated with “◯”, and those with insufficient gloss or unevenness were judged as rejected and indicated with “x” in the table.

  As shown in Tables 1-1 to 1-2, No. 1 in Example 1 was obtained. 101-107 and no. In 103I to 107I, all of the contact resistance, solderability, and surface gloss met the standards, and were suitable as metal materials for connecting parts such as connectors. In contrast, No. 1 of Comparative Example 1 was used. 111-116 and no. In 113I to 115I, at least one of contact resistance, solderability, and surface gloss was unacceptable.

  As shown in Tables 2-1 to 2-2, 201-207 and No. 1 of Example 1 were used. In 203I to 207I, all of the contact resistance, solderability, and surface glossiness met the standards, and were suitable as metal materials for connecting parts such as connectors. On the other hand, the comparative example 2 No. 211-216 and no. In 213I to 215I, at least one of contact resistance, solderability, and surface gloss was unacceptable.

  As shown in Tables 3-1 to 3-2, Examples 301 to 307 and No. 3 were used. In 303I to 307I, all of the contact resistance, solderability, and surface glossiness were satisfied, and were suitable as metal materials for connecting parts such as connectors. On the other hand, the comparative example 3 No. 311 to 316 and No.3. In 313I-315I, at least one of contact resistance, solderability, and surface gloss was unacceptable.

  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.

1 Base material 2 Copper tin alloy layer 3 Nickel layer

Claims (5)

A metal square wire for connecting parts in which a copper or copper alloy square wire is used as a base material, and a copper tin alloy layer substantially composed of copper and tin is formed on the outermost surface thereof ,
On the base material, a layer made of nickel, cobalt, iron or an alloy thereof is formed,
Copper-tin alloy layer of the outermost surface, 0 further zinc, indium, gallium, lead, cadmium, magnesium, gold, at least one selected from the group consisting of aluminum, by mass ratio of the content of the tin in a total amount A metal square wire for connecting parts, characterized by containing .01% or more and 1% or less . 2. The metal square wire for connecting parts according to claim 1, wherein a thickness of the layer made of nickel, cobalt, iron or an alloy thereof is 0.02 to 3.0 μm. Copper or rectangular wire material of copper alloy as a base material, nickel on the base metal, cobalt, layers were formed with iron or an alloy, further, zinc, indium, gallium, lead, cadmium, magnesium, gold, After forming a tin alloy plating layer containing at least one selected from the group of aluminum in a total amount of 0.01% by mass or more and 1% by mass or less to obtain an intermediate material, the intermediate material is subjected to heat treatment, method for producing a connection component metal angle wire and forming an alloy layer containing copper and tin on the surface. The method for producing a metal square wire for connecting parts according to claim 3, wherein the thickness of the tin alloy plating layer before the heat treatment is 0.3 to 0.8 µm. The method for manufacturing a metal square wire for connecting parts according to claim 3, wherein the heat treatment is a reflow treatment.

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