JP2018016878A - Manufacturing method of tin plating copper terminal material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a tin plating terminal material having no generation of electric corrosion by using copper or a copper alloy substrate as a terminal which is crimped to a terminal of a wire consisting of an aluminum wire material.SOLUTION: A manufacturing method has a ground layer forming process for forming a ground layer consisting of nickel or nickel alloy with a nickel percentage content of 80 mass% or more with thickness of 0.1 μm to 5.0 μm on a surface of a substrate consisting of copper or copper alloy, a tin zinc alloy layer forming process for forming a tin zinc alloy layer with zinc percentage content of 3 mass% to 35 mass% with thickness of 0.1 μm to 5.0 μm on the ground layer and a tin plating process for forming a tin layer by conducting tin plating on the tin zinc alloy layer.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method of manufacturing a tin-plated copper terminal material that is used as a terminal to be crimped to an end of an electric wire made of an aluminum wire, and in which a copper or copper alloy base material is plated with tin or a tin alloy.

Conventionally, by crimping a terminal made of copper or a copper alloy to the terminal part of an electric wire made of copper or a copper alloy, and connecting the terminal to a terminal of another device, Connecting to equipment is done. Further, in order to reduce the weight of the electric wire, the electric wire may be made of aluminum or aluminum alloy instead of copper or copper alloy.
For example, Patent Document 1 discloses an aluminum wire for an automobile wire harness made of an aluminum alloy.

  By the way, when the electric wire (conducting wire) is made of aluminum or an aluminum alloy and the terminal is made of copper or a copper alloy, when water enters the crimping portion (engagement portion between the terminal and the electric wire), it depends on the potential difference between different metals. Galvanic electric corrosion may occur. And with the corrosion of the electric wire, there is a risk that an increase in the electric resistance value at the crimping portion and a decrease in the adhering force (bonding force between the terminal and the electric wire) may occur.

Examples of methods for preventing this corrosion include those described in Patent Document 2 and Patent Document 3.
In Patent Document 2, an anticorrosion layer made of a metal having a sacrificial anticorrosive action on the base material layer is formed between the base material layer made of iron or an iron alloy and the tin layer formed on the outermost side. A terminal is disclosed. As the anticorrosion layer, a layer made of zinc or a zinc alloy is described.

Patent Document 3 has a base material made of a metal material, an alloy layer formed on the base material, and a conductive coating layer formed on the surface of the alloy layer as an electrical contact material for the connector. The alloy layer essentially contains Sn, and further contains one or more additive elements M selected from Cu, Zn, Co, Ni and Pd, and the conductive coating layer 4 is made of Sn. What contains ₃ O ₂ (OH) ₂ hydroxide oxide is disclosed.
In addition, as an example of adding Zn to Sn, in Patent Document 4, a Sn plating material having a base Ni plating layer, an intermediate Sn—Cu plating layer, and a surface Sn plating layer on the surface of copper or a copper alloy in order, The underlying Ni plating layer is made of Ni or a Ni alloy, and the intermediate Sn—Cu plating layer is made of a Sn—Cu alloy in which a Sn—Cu—Zn alloy layer is formed on at least the side in contact with the surface Sn plating layer. An Sn plating layer is composed of an Sn alloy containing 5 to 1000 ppm by mass of Zn, and an Sn plating material further having a Zn high concentration layer with a Zn concentration of more than 0.1 to 10% by mass on the outermost surface is disclosed. Has been.

JP 2004-134212 A JP 2013-218866 A Japanese Patent Laid-Open No. 2015-133306

However, when an anticorrosion layer made of zinc or a zinc alloy is provided on the base as in Patent Document 2, Sn substitution occurs when Sn plating is performed on the anticorrosion layer, resulting in poor adhesion between the anticorrosion layer and the Sn plating. There was a problem. Even when a SnSn ₃ O ₂ (OH) ₂ hydroxide oxide layer is provided as in Patent Document 3, the hydroxide oxide layer is rapidly damaged when exposed to a corrosive environment or a heating environment. There was a problem of low nature. Further, as in Patent Document 4, a Zn—Sn alloy layered on a Sn—Cu alloy layer and a Zn high-concentration layer on the surface layer has poor productivity of Sn—Zn alloy plating. When Cu is exposed on the surface layer, there is a problem that the anticorrosive effect on the aluminum wire is lost.

  The present invention has been made in view of the above-described problems, and is a tin-plated terminal material that does not cause electrolytic corrosion using a copper or copper alloy base material as a terminal to be crimped to an end of an electric wire made of an aluminum wire. An object is to provide a manufacturing method.

  In the method for producing a tin-plated copper terminal material of the present invention, a tin-zinc alloy layer having a zinc content of 3% by mass or more and 35% by mass or less is formed on a substrate made of copper or a copper alloy by 0.1 μm or more and 5. A tin-zinc alloy layer forming step of forming a thickness of 0 μm or less; and a tin plating step of forming a tin layer by applying tin plating on the tin-zinc alloy layer.

  In this method for producing a tin-plated copper terminal material, by forming a tin-zinc alloy layer before the tin plating step, the substitution reaction during tin plating can be suppressed and the adhesion of the tin layer can be improved. . And since the metallic zinc in the tin-zinc alloy layer formed under the tin layer diffuses into the tin layer, the surface tin layer contains metallic zinc whose corrosion potential is closer to that of aluminum than tin. Generation of electrolytic corrosion due to contact with the electric wire can be suppressed.

In this case, if the zinc content in the tin-zinc alloy layer exceeds 35% by mass, a substitution reaction occurs during tin plating, the adhesion of the tin layer is significantly reduced, and zinc diffuses excessively, resulting in contact resistance. Getting worse. If the zinc content is less than 3% by mass, zinc is not sufficiently diffused, and the effect of lowering the corrosion potential of the surface cannot be obtained.
Further, if the thickness of the tin-zinc alloy layer is less than 0.1 μm, there is no effect of lowering the corrosion potential on the surface of the tin layer, and if it exceeds 5.0 μm, there is a possibility that cracking may occur during pressing into the terminal.
In addition, since a tin-zinc alloy layer having a corrosion potential relatively close to that of aluminum is formed between the base material and the surface tin layer, even if the tin layer disappears and the tin-zinc alloy layer is exposed, the electric The occurrence of food can be suppressed.

  In the method for producing a tin-plated copper terminal material according to the present invention, before the tin-zinc alloy layer forming step, a base layer made of nickel or a nickel alloy having a nickel content of 80% by mass or more is formed on the surface of the base material. It is preferable to have a base layer forming step of forming a thickness of 1 μm or more and 5.0 μm or less.

The adhesion of the tin-zinc alloy layer is enhanced by forming the tin-zinc alloy layer after providing the base layer made of nickel or nickel alloy on the base material. If the thickness of the underlayer is less than 0.1 μm, the effect of increasing the adhesion of the tin-zinc alloy layer is poor, and the effect is saturated even if the film is formed with a thickness exceeding 5.0 μm. If the nickel content in the underlayer is less than 80% by mass, the effect of improving the adhesion is poor.
Further, the provision of the underlayer also has an effect of preventing the diffusion of copper from the base material made of copper or copper alloy to the tin-zinc alloy layer or tin layer.

  In the method for producing a copper terminal material with tin plating according to the present invention, after the tin plating step, diffusion is performed by diffusing zinc in the tin-zinc alloy layer into the tin layer by holding at 40 ° C. or more and 160 ° C. or less for 30 minutes or more. It is good to have a processing step.

  The diffusion of metallic zinc in the tin-zinc alloy layer described above occurs even at room temperature, but by performing diffusion treatment under this temperature condition, the diffusion of zinc can be promptly generated. Below 40 ° C., the effect of diffusing zinc in a short time is poor. When exposed to a temperature of 40 ° C. or more for 30 minutes or more, a concentrated layer of metallic zinc can be reliably formed on the surface of the tin layer. When the temperature exceeds 160 ° C., tin diffuses to the tin-zinc alloy layer side and inhibits the diffusion of zinc. Further, when the temperature exceeds 190 ° C., the tin layer is melted, the tin-zinc alloy layer repels molten tin, and a tin repelling portion is generated.

  In the method for manufacturing a tin-plated copper terminal material according to the present invention, the base material is previously formed into a hoop material by press working, and the hoop material is formed in a strip shape and in the length direction thereof. It is preferable that a plurality of terminal members to be formed on the terminal are connected to the along carrier part at intervals in the length direction of the carrier part.

  By processing the terminal member in advance, a tin-zinc alloy layer and a tin layer are formed on the end face of the base material, and an excellent anticorrosive effect can be exhibited including the end face.

  According to the method for producing a copper terminal material with tin plating of the present invention, by forming a tin-zinc alloy layer before the tin plating step, the substitution reaction during tin plating is suppressed and the adhesion of the tin layer is improved. Can be made. Furthermore, the occurrence of electrolytic corrosion due to contact with the aluminum electric wire can be suppressed by diffusion of metallic zinc into the tin layer. In addition, the metal zinc in the tin layer can be maintained at a high concentration by diffusion from the tin-zinc alloy layer under the tin layer, and a terminal having excellent corrosion resistance can be formed in the long term.

It is a flowchart which shows one Embodiment of the manufacturing method of the copper alloy terminal material with a tin plating which concerns on this invention. It is sectional drawing which shows typically embodiment of the copper alloy terminal material with a tin plating manufactured by the manufacturing method of this invention. It is a top view of the terminal material of an embodiment. It is a perspective view which shows the example of the terminal to which the terminal material of embodiment is applied. It is a front view which shows the terminal part of the electric wire which crimped | bonded the terminal of FIG. 6 is a micrograph of a cross section of Sample 8 before forming a tin layer. It is the microscope picture of the cross section after forming a tin layer about the sample 8 and carrying out the diffusion process.

The manufacturing method of the tin-plated copper terminal material of embodiment of this invention is demonstrated.
The tin-plated copper terminal material 1 formed by the manufacturing method of this embodiment will be described. The tin-plated copper terminal material 1 is formed with a plurality of terminals as shown in FIG. A plurality of terminal members 22 to be molded as terminals are arranged at intervals in the length direction of the carrier portion 21 on the carrier portion 21 along the length direction. The member 22 is connected to the carrier portion 21 via a narrow connecting portion 23. Each terminal member 22 is formed into the shape of the terminal 10 as shown in FIG. 4, for example, and is cut from the connecting portion 23 to complete the terminal 10.
The terminal 10 is a female terminal in the example of FIG. 4, and a connecting portion 11 into which a male terminal (not shown) is fitted from the tip, and a caulking portion in which the exposed core wire 12 a of the electric wire 12 is caulked. 13. A covering caulking portion 14 to which the covering portion 12b of the electric wire 12 is caulked is integrally formed in this order.
FIG. 5 shows a terminal portion structure in which the terminal 10 is caulked to the electric wire 12, and the core wire caulking portion 13 is in direct contact with the core wire 12 a of the electric wire 12.

  And this copper terminal material 1 with a tin plating, as typically shown in FIG. 2, on the base material 2 which consists of copper or a copper alloy, the base layer 3 which consists of nickel or a nickel alloy, the tin zinc alloy layer 4, Tin layer 5 is laminated in this order.

Next, the manufacturing method of this copper terminal material 1 with a tin plating is demonstrated.
If the base material 2 consists of copper or a copper alloy, the composition in particular will not be limited.
Then, the base material 2 is processed into a hoop material having a shape shown in FIG. 3 by press working or the like (base material processing step), and the base layer formation for forming the base layer 3 made of nickel or a nickel alloy is formed on the hoop material. A step, a tin-zinc alloy layer forming step for forming the tin-zinc alloy layer 4, a tin plating step for forming a tin layer 5 made of tin or a tin alloy, and a predetermined temperature after holding the tin layer 5 By doing so, the diffusion treatment process for diffusing zinc of the tin-zinc alloy layer 4 into the tin layer 5 is performed in this order.
Hereinafter, each will be described according to the flowchart of FIG.
<Base material processing step>
By processing the plate material such as cutting and punching, a plurality of terminal members 22 are formed into a hoop material connected to the carrier portion 21 via the connecting portion 23 as shown in FIG. After pressing, the surface is cleaned by degreasing, pickling and the like.

<Underlayer formation process>
The base layer 3 is formed on the hoop material after the base material processing step.
The nickel or nickel alloy plating for forming the underlayer 3 is not particularly limited as long as a dense nickel-based film can be obtained. Electricity using a known watt bath, sulfamic acid bath, citric acid bath or the like can be used. It can be formed by plating. As nickel alloy plating, nickel tungsten (Ni-W) alloy, nickel phosphorus (Ni-P) alloy, nickel cobalt (Ni-Co) alloy, nickel chromium (Ni-Cr) alloy, nickel iron (Ni-Fe) alloy, A nickel zinc (Ni—Zn) alloy, a nickel boron (Ni—B) alloy, or the like can be used.
Considering the press bendability to the terminal 10 and the barrier property against copper, pure nickel plating obtained from a sulfamic acid bath is desirable.
The underlayer 3 thus formed has a thickness of 0.1 μm to 5.0 μm and a nickel content of 80% by mass or more. The underlayer 3 has a function of preventing copper diffusion from the base material 2 to the zinc-nickel alloy layer 4 and the tin layer 5, and is less effective in preventing copper diffusion when its thickness is less than 0.1 μm. If it exceeds 0.0 μm, cracking is likely to occur during press working. The thickness of the underlayer 3 is more preferably 0.3 μm or more and 2.0 μm or less.
Further, when the nickel content is less than 80% by mass, the effect of preventing copper from diffusing into the zinc-nickel alloy layer 4 and the tin layer 5 is small. The nickel content is more preferably 90% by mass or more.

<Tin zinc alloy layer formation process>
The tin-zinc alloy plating for forming the tin-zinc alloy layer 4 is not particularly limited as long as a dense film can be obtained with a desired composition. Known cyan bath, sulfosuccinic acid bath, gluconic acid bath, citric acid It is possible to use a bath, pyrophosphoric acid bath or borofluoride bath. It is also possible to form a film by sputtering or vapor deposition instead of plating.
The tin-zinc alloy layer 4 formed by this step has a zinc content of 3% by mass to 35% by mass and a thickness of 0.1 μm to 5.0 μm.
When the zinc content in the tin-zinc alloy layer 4 exceeds 35% by mass, a substitution reaction occurs during tin plating described later for forming the tin layer 5, and the adhesion of the tin plating (tin layer) is significantly reduced. To do. Further, the zinc in the tin-zinc alloy layer 4 has the effect of diffusing into the tin layer 5 and lowering the corrosion potential of the surface. However, when the zinc content exceeds 35 mass%, the zinc is excessive. Diffusion causes contact resistance to deteriorate. If the zinc content is less than 3% by mass, zinc is not sufficiently diffused, and the effect of lowering the corrosion potential of the surface cannot be obtained. The zinc content in the tin-zinc alloy layer 4 is more preferably 5% by mass or more and 15% by mass or less.
In addition, since most zinc in the tin-zinc alloy layer 4 is diffused into the tin layer 5 by the diffusion treatment described later, the zinc concentration in the tin-zinc alloy layer 4 is greatly reduced after the diffusion treatment.
In addition, if the thickness of the tin-zinc alloy layer 4 is less than 0.1 μm, there is no effect of lowering the corrosion potential on the surface of the tin layer 5, and if it exceeds 5.0 μm, there is a possibility that cracks may occur during pressing into terminals. is there.

<Tin plating process>
Tin or tin alloy plating for forming the tin layer 5 can be performed by a known method. For example, an organic acid bath (for example, a phenol sulfonic acid bath, an alkane sulfonic acid bath or an alkanol sulfonic acid bath), borofluoric acid Electroplating can be performed using an acidic bath such as a bath, a halogen bath, a sulfuric acid bath, or a pyrophosphoric acid bath, or an alkaline bath such as a potassium bath or a sodium bath.
In view of the formation of the plating film at high speed, the denseness of the plating film, and the ease of diffusion of zinc, it is preferable to use an acidic organic acid bath or a sulfuric acid bath.
The thickness of the tin layer 5 formed by this process is preferably 0.1 μm or more and 10 μm or less. If it is too thin, there is a risk of lowering solder wettability and contact resistance. There is a risk that the attachment / detachment resistance at the time of use in a connector or the like increases.

<Diffusion treatment process>
In this diffusion treatment step, the surface temperature of the material is kept at a temperature that is 40 ° C. or higher and 160 ° C. or lower for 30 minutes or longer. By this diffusion treatment, zinc in the tin-zinc alloy layer 4 diffuses into the tin layer 5. Since zinc diffusion occurs quickly, it may be exposed to a temperature of 40 ° C. or higher for 30 minutes or longer. However, when the temperature exceeds 160 ° C., tin diffuses to the tin-zinc alloy layer 4 side and inhibits the diffusion of zinc. When the temperature exceeds 190 ° C., the tin-zinc alloy repels molten tin, and the tin layer 5 has a location where tin repels. In order to form, it does not heat to the temperature exceeding 190 degreeC.

The tin-plated copper terminal material 1 manufactured in this manner is obtained by laminating a base layer 3 made of nickel or a nickel alloy, a tin-zinc alloy layer 4 and a tin layer 5 in this order on a base material 2 as a whole. Yes.
And it forms into the terminal 10 by processing into the shape of the terminal 10 shown in FIG.
FIG. 5 shows a terminal portion structure in which the terminal 10 is caulked to the electric wire 12, and the core wire caulking portion 13 is in direct contact with the core wire 12 a of the electric wire 12.

Since this terminal 10 contains zinc whose corrosion potential is closer to that of aluminum than tin in the tin layer 5 on the surface, even if the terminal 10 is crimped to the aluminum core wire 12a, the occurrence of electrolytic corrosion is prevented. Can be prevented. In this case, since the plating treatment was performed in the state of the hoop material in FIG. 3 and the heat treatment was performed, the base material 2 was not exposed on the end surface of the terminal 10, and thus an excellent anticorrosion effect could be exhibited.
Moreover, since the tin-zinc alloy layer 4 is formed under the tin layer 5 and the zinc diffuses into the tin layer 5, the zinc in the tin layer 5 is maintained at a high concentration. Even if all or part of the tin layer 5 disappears due to wear or the like, the tin-zinc alloy layer 4 below has a corrosion potential close to that of aluminum, so that the occurrence of electrolytic corrosion can be suppressed.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
In the said embodiment, although the diffusion process process was provided after the tin plating process, this diffusion process process is not necessarily required and you may process into a terminal without passing through a diffusion process process. The zinc is preferably diffused quickly through the above-described diffusion treatment step. However, the metal zinc is removed from the tin-zinc alloy layer 4 by leaving it at a room temperature of 10 ° C. or higher, for example, without passing through the diffusion treatment step. It can be diffused into the tin layer 5.
Moreover, the electric wire 12 can be applied to any of a bare electric wire with a conductive wire exposed and a covered electric wire having a conductive wire as a core wire and a periphery covered with an insulating layer. In the present invention, both the bare wire and the core wire of the covered wire are referred to as an electric wire.

After electrolytic degreasing and pickling the copper plate of the base material, nickel plating, tin-zinc alloy plating, and tin plating as an underlayer were sequentially applied. The conditions for each plating were as follows.
The underlayer and tin-zinc alloy obtained by these plating treatments have the thicknesses shown in Table 1. Samples 1, 2, 11 to 13 did not form an underlayer, and sample 10 was not subjected to tin-zinc alloy plating.

<Nickel plating conditions>
・ Plating bath composition Nickel sulfamate: 300 g / L
Nickel chloride: 5g / L
Boric acid: 30 g / L
・ Bath temperature: 45 ℃
・ Current density: 5 A / dm ²

<Tin zinc alloy plating conditions>
・ Plating bath composition Tin (II) sulfate: 40 g / L
Zinc sulfate heptahydrate: 5g / L
Trisodium citrate: 65 g / L
Nonionic surfactant: 1 g / L
・ PH = 5.0
・ Bath temperature: 25 ° C
・ Current density: 3 A / dm ²
This tin-zinc alloy plating condition is an example in which the zinc content is 15% by mass, and the zinc content in the tin-zinc alloy layer is adjusted by adjusting the concentration ratio of tin and zinc in the plating bath. The content shown in FIG.

<Tin plating conditions>
・ Plating bath composition Tin methanesulfonate: 200 g / L
Methanesulfonic acid: 100 g / L
Brightener and bath temperature: 25 ° C
・ Current density: 5 A / dm ²

  The zinc content in the tin-zinc alloy layer was accelerated from the surface using a JXA-8530F manufactured by JEOL Ltd., an electron beam microanalyzer (EPMA), under a predetermined plating condition. Observation was performed at a voltage of 6.5 kV, and measurement was performed with a beam diameter of φ30 μm.

  And among the copper plates with plating layers in which an underlayer, a tin-zinc alloy layer, and a tin layer were formed in order, Samples 4 to 9 were subjected to diffusion treatment under the temperature conditions shown in Table 1 to obtain samples.

  The obtained samples were measured and evaluated for corrosion current, bending workability, presence / absence of interface voids, and contact resistance.

<Corrosion current>
For the corrosion current, a pure aluminum wire covered with a resin leaving an exposed portion with a diameter of 2 mm and a sample coated with a resin leaving an exposed portion with a diameter of 6 mm were placed with the exposed portion facing each other at a distance of 1 mm, The corrosion current flowing between the aluminum wire and the sample in 5% by mass saline was measured. For the corrosion current measurement, a resistance resistance ammeter HA1510 manufactured by Hokuto Denko Corporation was used, and the corrosion currents after the sample was heated at 150 ° C. for 1 hour and before the heating were compared. The average current value for 1000 minutes was compared.

<Bending workability>
Regarding the bending workability, the test piece was cut out so that the rolling direction was long, and using a W bending test jig defined in JISH3110, 9.8 × 10 ³ N so as to be perpendicular to the rolling direction. Bending was performed with a load of. Then, it observed with the stereomicroscope. For the evaluation of bending workability, the level at which no clear crack is observed in the bent part after the test is evaluated as “excellent”, and the level at which the copper alloy base material is not exposed due to the generated crack is evaluated as “good”. The level at which the copper alloy base material was exposed due to the generated cracks was evaluated as “bad”.

<Contact resistance>
The contact resistance measurement method conforms to JCBA-T323, using a four-terminal contact resistance tester (manufactured by Yamazaki Seiki Laboratories: CRS-113-AU), sliding resistance (1 mm) and contact resistance at a load of 0.98 N Was measured. Measurement was performed on the plated surface of the flat plate sample.

<Interface void>
The presence or absence of interface voids due to tin substitution during tin plating was performed by cross-sectioning the sample with a cross section polisher and observing the vicinity of the interface between the tin-zinc alloy layer and the tin layer with an electrolytic emission scanning electron microscope. The case where a clear void exceeding 3 μm was observed was judged as “Yes”, and the case where no clear void was present was marked as “None”.
These results are shown in Table 2.

From the results in Table 2, Samples 1 to 9, which were tin-plated after a tin-zinc alloy layer having a zinc content of 3% by mass to 35% by mass with a thickness of 0.1 μm to 5.0 μm, were attributed to tin substitution. It can be seen that the generation of voids is very little or not at all, and has an excellent electrolytic corrosion prevention effect and good bending workability.
Samples 5 to 9 in which a base layer having a thickness of 0.1 μm or more and 5.0 μm or less and a nickel content of 80% by mass or more is formed between the base material and the tin-zinc alloy layer have the base layer. Samples 1, 8, and 9 that have a better electric corrosion prevention effect than samples 1 and 2 that are held at a temperature of 40 ° C. or higher and 160 ° C. or lower for 30 minutes or more as diffusion treatment, have bending workability. It is good and the contact resistance is lower than others, which is a particularly excellent result.

  On the other hand, since the sample 10 of the comparative example did not form a tin-zinc alloy layer, the corrosion current was high. In Sample 11, since the zinc content of the tin-zinc alloy layer was high, an interface void was generated, the adhesion of the tin layer was lowered (bending workability was deteriorated), and the contact resistance was increased. In Sample 12, the zinc content of the tin-zinc alloy layer was less than 3% by mass, so that the zinc diffusion was insufficient, the surface corrosion current was high, and the bending workability was also deteriorated. In Sample 13, since the tin-zinc alloy layer was as thick as 6 μm, the bending workability deteriorated. In Sample 14, the tin-zinc alloy layer was too thin at 0.07 μm, so that the zinc diffusion was insufficient and the corrosion current was high.

  6 is a micrograph of a cross section of the sample 8 after forming a tin-zinc alloy layer on the underlayer. FIG. 7 shows a diffusion process in which a tin layer is formed on the tin-zinc alloy layer. It is the microscope picture of the cross section after giving. In FIG. 7, zinc appears white and spotted in the tin layer, and zinc in the tin-zinc alloy layer is reduced and diffused in the thickness direction of the tin layer.

DESCRIPTION OF SYMBOLS 1 Copper terminal material with tin plating 2 Base material 3 Underlayer 4 Tin zinc alloy layer 5 Tin layer 10 Terminal 11 Connection part 12 Electric wire 12a Core wire 12b Covering part 13 Core wire crimping part 14 Covering crimping part

Claims (4)

  A tin-zinc alloy layer forming step of forming a tin-zinc alloy layer having a zinc content of 3% by mass or more and 35% by mass or less on a substrate made of copper or a copper alloy with a thickness of 0.1 μm or more and 5.0 μm or less. And a method of producing a tin-plated copper terminal material comprising a tin plating step of forming a tin layer by performing tin plating on the tin-zinc alloy layer.   Before the step of forming the tin-zinc alloy layer, a base layer made of nickel or a nickel alloy having a nickel content of 80% by mass or more is formed on the surface of the substrate with a thickness of 0.1 μm or more and 5.0 μm or less. It has a formation formation process, The manufacturing method of the copper terminal material with a tin plating of Claim 1 characterized by the above-mentioned.   3. A diffusion treatment step of diffusing zinc in the tin-zinc alloy layer into the tin layer by holding at 40 ° C. or more and 160 ° C. or less for 30 minutes or more after the tin plating step. The manufacturing method of the copper terminal material with a tin plating of description. The base material is previously formed into a hoop material by press working, and the hoop material is formed in a band plate shape, and a plurality of terminals to be formed into terminals on a carrier portion along the length direction thereof. The method for producing a tin-plated copper terminal material according to any one of claims 1 to 3, wherein the members for use are connected with an interval in the length direction of the carrier portion.