JP5479767B2 - Metal square wire for connecting parts and manufacturing method thereof - Google Patents

Description

  The present invention relates to a metal material for connection parts and a method for manufacturing the same, and more particularly to a metal material for connection parts having sufficient gloss after reflow and a method for manufacturing the metal material.

  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

  By the way, in the conductive material for connecting parts, when the base material is a square wire, the surface properties after the heat treatment may be deteriorated when the Sn plated wire is manufactured by the heat treatment such as the reflow treatment. There is also a phenomenon that whiskers are generated despite the reflow process. These phenomena are considered to occur due to the fact that Sn on the square wire melts and flows during the reflow process, and the distribution of Sn becomes non-uniform. There is no description about the case of a wire rod, and a new approach is required to solve this problem.

  Therefore, an object of the present invention is to provide a metal material for connection parts that has good surface properties after heat treatment and is less likely to generate whiskers, and a method for manufacturing the same.

The above-mentioned subject is achieved by the following means. That is, the present invention
(1) A metal square wire for connecting parts in which a copper or copper alloy square wire is used as a base material, and an alloy layer mainly composed of tin is formed on the outermost surface thereof . A layer of cobalt, iron, or an alloy thereof is formed, and the alloy layer mainly composed of tin on the outermost surface is selected from at least one of the following two groups (A) and (B): Metal square wire for connecting parts, characterized in that it contains 0.01% by mass to 2% by mass in total of elements,
(A) Ga, P b, C d, Mg, at least one selected from the group of A u, containing less than 1 wt% 0.01 wt% per one.
(B) It contains 0.01 to 0.5% by mass of Al .
(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 copper or copper alloy square wire is used as a base material, and a layer made of nickel, cobalt, iron, or an alloy thereof is formed on the base material . Further, the following two groups (A) and (B): An intermediate material is obtained by forming a tin alloy plating layer containing a total amount of elements selected from at least one group of 0.01% by mass to 2% by mass, and then the intermediate material is heat-treated. A method of manufacturing a metal square wire for connecting parts,
(A) Ga, P b, C d, Mg, at least one selected from the group of A u, containing less than 1 wt% 0.01 wt% per one.
(B) Al is contained in an amount of 0.01 to 0.5% by mass.
(4) The method for producing a metal square wire for connecting parts according to (3), wherein the tin alloy plating layer before the heat treatment has a thickness of 0.8 to 1.2 μm, 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 has tin as a main component on the outermost surface of a base material of copper or a copper alloy square wire (including a square bar), and the following two (A) and (B): Since the total amount of elements selected from at least one of the groups is 0.01% by mass or more and 2% by mass or less, it does not depend on the irregularities on the surface of the base material and has sufficient gloss after heat treatment, , A metal material that is less likely to generate whiskers.
(A) At least one selected from the group consisting of Ga, In, Pb, Bi, Cd, Mg, Zn, Ag, and Au is contained in an amount of 0.01% by mass to 1% by mass.
(B) At least one selected from Al or Cu is contained in an amount of 0.01 to 0.5% by mass.

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. It is a partial expansion schematic sectional drawing of the metal material (square wire) for connection components of Example 4. FIG.

The metal material for connecting parts of the present invention has a square wire formed of copper or a copper alloy as a base material, tin as a main component on the outermost surface, and further, among the following two groups (A) and (B): The total amount of elements selected from at least one group is 0.01% by mass or more and 2% by mass or less.
(A) At least one selected from the group consisting of Ga, In, Pb, Bi, Cd, Mg, Zn, Ag, and Au is contained in an amount of 0.01% by mass to 1% by mass.
(B) At least one selected from Al or Cu is contained in an amount of 0.01 to 0.5% by mass.

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 0.01% by mass or more and 2% by mass or less of an element selected from at least one of the following two groups (A) and (B).
(A) At least one selected from the group consisting of Ga, In, Pb, Bi, Cd, Mg, Zn, Ag, and Au is contained in an amount of 0.01% by mass to 1% by mass.
(B) At least one selected from Al or Cu is contained in an amount of 0.01 to 0.5% by mass.

Further, if the 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, more preferably 0.8 to 1.2 μm, and 0.8 to 1 More preferably, the thickness is 0.0 μm.
In the present invention, the tin alloy plating may be formed by electroless plating, but is preferably formed by electroplating.
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 2 or more Is preferable, and it is more preferable that it is 2.0-3.0.

  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. And the alloy layer containing copper and tin on the outermost surface is 0.01% by mass or more and 2% by mass or less of elements selected from at least one of the following two groups (A) and (B): Since it contains, it can be set as the metal material for connection components with the favorable surface property after heat processing, and the solderability in a post process favorable.
(A) At least one selected from the group consisting of Ga, In, Pb, Bi, Cd, Mg, Zn, Ag, and Au is contained in an amount of 0.01% by mass to 1% by mass.
(B) At least one selected from Al or Cu is contained in an amount of 0.01 to 0.5% by mass.

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 (indicated as Ra = large in the table) and Ra = 0.05 μm (indicated in the table as Ra = small).
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.
Tin alloy plating and elements added thereto: (A) Select Zn and In from the group of Ga, In, Pb, Bi, Cd, Mg, Zn, Ag, Au, and (B) Select Al and Cu , Zn ions, In ions, Cu ions, Al ions were prepared in appropriate amounts.
Measurement of concentration of additive element during Sn plating: plating was performed on stainless steel, 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 0.9 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 is a base material, 2 is a tin alloy plating layer, and 3 is a copper tin alloy layer.

Comparative Example 1
A tin alloy plating with a thickness of 0.9 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 with 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 with a thickness of 0.9 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 is a base material, 2 is a tin alloy plating layer, and 3 is a copper tin alloy layer. The copper plating layer was all converted to the copper tin alloy layer 3 by reacting with the outermost tin alloy plating by the reflow treatment.

Comparative Example 2
After applying a copper plating with 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 with a thickness of 0.9 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 3 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 tin alloy plating with a thickness of 0.9 μm was performed. 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. 3, 1 is a base material, 2 is a tin alloy plating layer, and 4 is a nickel layer.

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 tin alloy plating with a thickness of 0.9 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.

Example 4
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, followed by a tin alloy plating with a thickness of 0.9 μm. 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. 4, 1 is a base material, 2 is a tin alloy plating layer, 3 is a copper tin alloy layer, and 4 is a nickel layer. The copper plating layer was all converted to the copper tin alloy layer 3 by reacting with the outermost tin alloy plating by the reflow treatment.

Comparative Example 4
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, followed by a tin alloy plating with a thickness of 0.9 μm. 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 3 by reacting with the outermost tin alloy plating by the reflow treatment.

Test Example An evaluation test was performed on the surface gloss, whisker property, and contact resistance of the square wires of Examples 1 to 4 and Comparative Examples 1 to 4. These results are shown in Tables 1-1 to 1-4 for Example 1 and Comparative Example 1, in Tables 2-1 to 2-4 for Example 2 and Comparative Example 2, and in Example 3 and Comparative Example 3. Are shown in Tables 3-1 to 3-4, and Example 4 and Comparative Example 4 are shown in Tables 4-1 to 4-4.
(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.
(Whisker)
The sample was left for 3 months with external stress applied by an indenter and examined for the occurrence of whiskers. A whisker that did not occur or a whisker length that occurred 50 μm or less was determined to be acceptable and indicated as “◯” in the table, and a whisker that exceeded 50 μm was determined to be unacceptable Indicated in the table by “x”.
(Contact resistance)
Common to all samples: Contact resistance was measured after exposure to the atmosphere at 120 ° C. for 120 hours. The measurement was performed by the 4-terminal method, and the contact was measured using an Ag probe with a load of 1N.
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".
Example 3, Comparative Example 3, Example 4, Comparative Example 4: The measurement method was the same as that after heating at 120 ° C. for 120 hours, and the contact resistance after exposure to the atmosphere at 160 ° C. for 120 hours was also measured.

  As shown in Tables 1-1 to 1-4, no. 401-406, no. 403I-406I, No. 401AZ-402AZ, no. 405AZ to 406AZ, and No. 405AZ. In 405AI to 406AI, all of the surface gloss, whisker property, and contact resistance satisfied the standards, and were suitable as metal materials for connection parts such as connectors. On the other hand, No. 1 of Comparative Example 1 was used. 411-417, no. 413I-416I, No. 411AZ-412AZ, no. 415AZ-416AZ, and No. 415AZ. In 415AI to 416AI, at least one of surface gloss, whisker property, and contact resistance was unacceptable.

  As shown in Tables 2-1 to 2-4, no. 501-506, no. 503I-506I, No. 501AZ-502AZ, no. 505AZ-506AZ, and No. In all of 505AI to 506AI, the surface gloss, whisker property, and contact resistance all met the standards, and were suitable as metal materials for connecting parts such as connectors. On the other hand, the comparative example 2 No. 511-517, no. 513I-516I, No. 511AZ-512AZ, no. 515AZ-516AZ, and No. 515AI to 516AI failed in at least one of surface gloss, whisker property, and contact resistance.

  As shown in Tables 3-1 to 3-4, no. 601-606, no. 603I-606I, No. 601AZ-602AZ, No. 605AZ-606AZ, and No. In each of 605AI to 606AI, all of the surface gloss, whisker property, and contact resistance met the standards, and were suitable as metal materials for connection parts such as connectors. On the other hand, the comparative example 3 No. 611-617, no. 613I-616I, No. 611AZ to 612AZ, No. 615AZ-616AZ, and No. In 615AI to 616AI, at least one of surface gloss, whisker property, and contact resistance was unacceptable.

  As shown in Tables 4-1 to 4-4, no. 701-706, no. 703I-706I, No. 701AZ-702AZ, no. 705AZ-706AZ, and No. In all of 705AI to 706AI, the surface gloss, whisker property, and contact resistance all met the standards, and were suitable as metal materials for connection parts such as connectors. On the other hand, the comparative example 4 No. 711-717, no. 713I-716I, No. 711AZ-712AZ, no. 715AZ-716AZ, and No. In 715AI to 716AI, at least one of surface gloss, whisker property, and contact resistance failed.

  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 Tin alloy layer 3 Copper tin alloy layer 4 Nickel layer

Claims (5)

A metal square wire for connecting parts in which a square wire of copper or copper alloy is used as a base material, and an alloy layer mainly composed of 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,
The alloy layer mainly composed of tin on the outermost surface contains 0.01% by mass or more and 2% by mass or less of elements selected from at least one of the following two groups (A) and (B): A metal square wire for connecting parts, characterized by:
(A) Ga, P b, C d, Mg, at least one selected from the group of A u, containing less than 1 wt% 0.01 wt% per one.
(B) It contains 0.01 to 0.5% by mass of Al . 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. A square wire material of copper or copper alloy is used as a base material, a layer made of nickel, cobalt, iron, or an alloy thereof is formed on the base material, and at least one of the following two groups (A) and (B): A connection characterized by forming an intermediate material by forming a tin alloy plating layer containing 0.01% by mass or more and 2% by mass or less of an element selected from two groups, and then subjecting the intermediate material to heat treatment Manufacturing method of metal square wire for parts.
(A) Ga, P b, C d, Mg, at least one selected from the group of A u, containing less than 1 wt% 0.01 wt% per one.
(B) Al is contained in an amount of 0.01 to 0.5% by mass. 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 0.8 to 1.2 µm. The method for manufacturing a metal square wire for connecting parts according to any one of claims 3 and 4, wherein the heat treatment is a reflow treatment.

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