JP7302364B2 - Connector terminal materials and connector terminals - Google Patents

Description

TECHNICAL FIELD The present invention relates to a connector terminal material provided with a film and a connector terminal which are useful for connecting electrical wiring in automobiles, consumer equipment, and the like, where microsliding occurs.

2. Description of the Related Art Conventionally, connectors used for connecting electrical wiring in automobiles and the like are known. In this in-vehicle connector (in-vehicle terminal), a contact piece provided on a female terminal is electrically connected by contacting a male terminal inserted into the female terminal with a predetermined contact pressure. are used with terminal pairs designed to As such connectors (terminals), tin-plated terminals, which are obtained by plating a copper or copper alloy plate with tin and performing a reflow treatment, have generally been used. However, in recent years, with the increase in current and voltage in automobiles, the use of precious metal-plated terminals, which are excellent in heat resistance and wear resistance and which allow more current to flow, is increasing.

As a method of plating a vehicle-mounted terminal that requires such heat resistance and wear resistance, there is a method of applying silver plating to the terminal as described in Patent Document 1, for example. In this regard, the hardness of the silver-plated layer decreases due to the enlargement of the crystal grain size of silver due to heating. When this hardness decreases, the wear resistance also decreases at the same time, making the silver plating layer more susceptible to wear. As a countermeasure, increasing the film thickness of the silver plating layer is conceivable, but there is a problem in terms of cost. . Moreover, when a nickel plating layer is used as a base of the silver plating layer, there is also a problem that the silver plating layer peels off due to oxidation of the nickel plating layer.
On the other hand, as in Patent Document 2, it is conceivable to add antimony to the silver plating layer to refine crystal grains in the silver plating layer and increase the hardness of the silver plating layer. However, although the initial hardness is high, the antimony in the silver plating layer concentrates on the outermost surface of the plating layer due to heating, which lowers the hardness, and the antimony in the surface layer is oxidized to increase the contact resistance. Furthermore, when a nickel-plated layer is used as an underlayer, nickel oxide is generated between the nickel-plated layer and the silver-plated layer by heating, and the nickel oxide may cause peeling of the plated layer.

In addition, as in Patent Document 3, there is a technique in which a silver plating layer and a tin plating layer are laminated in order and subjected to reflow treatment to alloy the surface. decreases.
Therefore, as in Patent Document 4, it has been considered to apply silver-tin alloy plating directly to the base material to keep the composition of the entire plating layer uniform.

Japanese Patent Application Laid-Open No. 2008-169408 Japanese Patent Application Laid-Open No. 2009-79250 Japanese Patent Application Laid-Open No. 2017-79143 JP 2015-183216 A

In order to directly and uniformly form the silver-tin plating layer of Patent Document 4 on the nickel plating layer, it is preferable to apply silver strike plating before applying silver-tin alloy plating. However, since nickel and silver are difficult to interdiffusion, and the alloyed silver-tin plating layer is very hard, there is a risk that it will peel off from the interface between the nickel plating layer and the silver strike plating layer, which have weak adhesion, during sliding.

It is an object of the present invention to provide a terminal material for a connector and a terminal for a connector in which the adhesiveness of the silver-tin alloy plating layer can be enhanced to improve wear resistance and heat resistance. aim.

The terminal material for a connector of the present invention comprises a base material having at least a surface made of copper or a copper alloy, a nickel plating layer formed on the surface of the base material, and an intermediate layer formed on at least a part of the nickel plating layer. A plated layer and a silver-tin alloy plated layer formed on the intermediate plated layer, the intermediate plated layer containing any one of Cu, Pd, Co, and Mn as a main component, and the intermediate plated layer The thickness of the layer is 0.02 μm or more, the silver-tin alloy plating layer contains Ag in the range of 70 at % or more and 85 at % or less, and the thickness of the silver-tin alloy plating layer is 0.5 μm or more and 5 μm or less. be.

This connector terminal material has excellent wear resistance due to the hard silver-tin alloy layer. In this case, since the nickel plating layer is formed on the surface of the base material, diffusion of the Cu component from the base material in a high-temperature environment is prevented, and performance deterioration of the silver-tin alloy plating layer is suppressed. The film thickness of the nickel plating layer is preferably 0.5 μm or more and 2.0 μm or less.
Further, since an intermediate layer containing any one of Cu, Pd, Co, and Mn as a main component is formed on the nickel plating layer as an intermediate layer, the adhesion between them is improved, and silver tin The wear resistance of the alloy plating layer can be effectively exhibited. If the film thickness of the intermediate plating layer is less than 0.02 μm, the film cannot be formed uniformly over the entire surface, so that the effect of improving wear resistance is reduced, and the silver-tin alloy plating layer tends to come off. From the standpoint of workability, the thickness of the intermediate plated layer is preferably 0.5 μm or less.
If the Ag content in the silver-tin alloy plating layer is less than 70 at%, the contact resistance after heating increases. descend. In addition, it becomes difficult to form a uniform film over the entire surface.
Examples of silver-tin-based intermetallic compounds include intermetallic compounds of Ag ₃ Sn and Ag ₄ Sn.
If the silver-tin alloy plating layer is less than 0.5 μm, the effect of improving wear resistance when used as a connector is poor. Although there is no problem even if the film thickness exceeds 5 μm, it is preferable to set the film thickness to 5 μm or less in terms of cost and workability.

As one aspect of the connector terminal material, a silver plating layer made of Ag with a purity of 99% by mass or more may be formed on the silver-tin alloy plating layer with a thickness of 0.1 μm or more and 2.0 μm or less. .

Since the silver-plated layer is formed on the silver-tin alloy-plated layer in this connector terminal material, the surface is not easily oxidized even in a heated environment, and an increase in contact resistance can be suppressed. In addition, since a silver-plated layer that is softer than the silver-tin alloy layer is formed on the relatively hard silver-tin alloy-plated layer, the slipperiness is improved and the connection/disconnection resistance when used as a connector is reduced. There is also an effect. If the film thickness of the silver plating layer is less than 0.1 μm, it is too thin, so the effect of suppressing the increase in contact resistance after heating is low, and the silver plating layer is likely to be worn away early. If the thickness exceeds 2.0 μm, the soft silver plating layer is thick and the coefficient of friction increases.

In the connector terminal made of the connector terminal material of the present invention, the surface of the contact portion with the mating connector terminal may be made of the silver-tin alloy plating layer or the silver plating layer.

ADVANTAGE OF THE INVENTION According to this invention, the adhesiveness of a silver tin alloy plating layer can be improved, and the abrasion resistance and heat resistance of a terminal material for connectors can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows typically the terminal material for connectors which concerns on one Embodiment of this invention. It is a scanning ion microscope (SIM) image of the cross section of the terminal material for connectors before heating in an Example.

An embodiment of the present invention will be described below with reference to the drawings.
[Configuration of terminal material for connector]
FIG. 1 schematically shows a cross section of a connector terminal material according to one embodiment. This connector terminal material 1 includes a plate-like base material 2 whose surface is at least made of copper or a copper alloy, a nickel plating layer 3 made of nickel or a nickel alloy coated on the surface of the base material 2, and a nickel plating layer. 3, a silver-tin alloy plating layer 5 formed on the intermediate plating layer 4, and a silver-plating layer formed on the silver-tin alloy plating layer 5. 6.

The composition of the base material 2 is not particularly limited as long as it is made of copper or a copper alloy. Alternatively, it may be composed of a plated material in which a copper-plated layer made of copper or a copper alloy is applied to the surface of the base material. In this case, the base material may be a metal material other than copper.

The nickel plating layer 3 is coated by plating the base material 2 with nickel or a nickel alloy. This nickel plating layer 3 has a function of suppressing the diffusion of Cu and alloy components from the substrate 2 into the silver-tin alloy plating layer 5 coated thereon. The thickness of this nickel plating layer 3 is preferably 0.5 μm or more and 2.0 μm or less. When the thickness of the nickel plating layer 3 is less than 0.5 μm, copper and alloy components diffuse from the base material 2 made of copper or a copper alloy into the upper plating layer in a high-temperature environment, whereby the connector terminal material 1 is formed. There is a possibility that the contact resistance value of the surface will increase and the heat resistance will decrease, and if it exceeds 2.0 μm, cracks may occur during bending. The composition of the nickel plating layer 3 is not particularly limited as long as it is made of nickel or a nickel alloy.

The intermediate plated layer 4 contains one of Cu, Pd, Co and Mn as a main component. The intermediate plated layer 4 has good adhesion to both the nickel plated layer 3 and the silver-tin alloy plated layer 5, thereby improving wear resistance. The film thickness of the intermediate plating layer 4 is 0.02 μm or more. If the thickness is less than 0.02 μm, the film cannot be uniformly formed on the entire surface. Although not particularly limited, the film thickness of the intermediate plated layer 4 is preferably 0.5 μm or less in terms of cost and workability. The contents of Cu, Pd, Co, and Mn in the intermediate plating layer 4 are not particularly limited, but preferably 90% by mass or more.

The silver-tin alloy plating layer 5 is coated on the upper surface of the intermediate plating layer 4 after silver strike plating, which will be described later, is applied. This silver-tin alloy plating layer 5 is mainly composed of intermetallic compounds of Ag ₃ Sn and Ag ₄ Sn and contains Ag in a range of 70 at % or more and 85 at % or less. Since it contains such an intermetallic compound, wear resistance is improved.

In addition, the silver-tin alloy plating layer 5 has the effect of supporting the soft silver plating layer 6 formed thereon and improving wear resistance when used as a connector. The thickness of the silver-tin alloy plating layer 5 is preferably 0.5 μm or more and 5 μm or less. If the silver-tin alloy plating layer 5 is less than 0.5 μm, the effect of improving the wear resistance becomes poor. There is no problem even if the film thickness exceeds 5 μm, but it is preferable to set the film thickness to 5 μm or less from the standpoint of workability.

The surface of the silver plating layer 6 is not easily oxidized even in a heating environment, and an increase in contact resistance can be suppressed. This silver plating layer 6 is made of pure silver with a purity of 99% by mass or more, preferably 99.9% by mass or more. The reason why the purity is set to 99% by mass or more is that if the Ag concentration of the silver plating layer 6 is less than 99% by mass, a large amount of impurities will be contained, resulting in an increase in contact resistance.
The film thickness of the silver plating layer 6 is 0.1 μm or more and 2.0 μm or less. If the film thickness of the silver plating layer 6 is less than 0.1 μm, it is too thin and is likely to be worn out early and disappear. When the film thickness exceeds 2.0 μm, the soft silver plating layer 6 becomes thick, so the coefficient of friction increases.

Next, a method for manufacturing the connector terminal material 1 will be described. The method for manufacturing the connector terminal material 1 includes a pretreatment step of washing a plate material made of copper or a copper alloy to be the base material 2, a nickel plating layer forming step of forming the nickel plating layer 3 on the base material 2, and a nickel plating layer forming step. An intermediate plating layer forming step of forming an intermediate plating layer 4 on the plating layer 3, a silver strike plating step of applying silver strike plating on the intermediate plating layer 4, and a silver-tin alloy plating layer 5 formed after the silver strike plating. A silver-tin alloy plating layer forming step and a silver-plating layer forming step of forming the silver plating layer 6 on the silver-tin alloy plating layer 5 are provided.

[Pretreatment process]
First, a plate material made of copper or a copper alloy is prepared as the base material 2, and pretreatment is performed to clean the surface of the plate material by degreasing, pickling, or the like.

[Nickel plating layer forming step]
At least part of the surface of the base material 2 is plated with nickel or a nickel alloy to form a nickel plating layer 3 on the base material 2 . For example, using a nickel plating solution containing 300 g/L of nickel sulfamate, 30 g/L of nickel chloride, and 30 g/L of boric acid, nickel plating is performed under the conditions of a bath temperature of 45° C. and a current density of 3 A/dm ² to form. be done. The nickel plating for forming the nickel layer 3 is not particularly limited as long as a dense nickel-based film can be obtained, and may be formed by electroplating using a known Watt bath.

[Intermediate plating layer forming step]
An intermediate plating layer 4 is formed after the surface of the nickel plating layer 3 formed on the substrate 2 is subjected to an activation treatment using a 5% to 10% by weight sulfuric acid aqueous solution. A plating bath for forming the intermediate plating layer 4 may be of any type as long as it can form a uniform film. If the intermediate plating layer 4 is a copper plating layer, it is a copper sulfate bath; if it is a palladium plating layer, it is a plating bath containing a palladium compound such as palladium chloride; if it is a cobalt plating layer, it is a plating bath containing cobalt sulfate; A typical plating bath for the metal species, such as a plating bath containing manganese sulfate, may be used.

[Silver strike plating process]
Silver plating is applied to the surface of the intermediate plating layer 4 for a short time to form a thin silver plating layer. Silver strike plating is preferable as the silver plating in this case. The composition of the plating solution for applying this silver strike plating is not particularly limited as long as it is a non-cyanide bath (a plating bath that does not contain cyanide such as silver cyanide, potassium silver cyanide, sodium cyanide, potassium cyanide, etc.). A bath mainly composed of a silver methanesulfonate bath is desirable. The silver strike plating layer formed by this silver strike plating becomes difficult to distinguish as a layer because a silver-tin alloy plating layer is formed thereafter.

[Silver-tin alloy plating layer forming process]
After applying silver strike plating, silver-tin alloy plating is applied to form the silver-tin alloy plating layer 5 . A plating bath for this silver-tin alloy plating has a composition containing, for example, methanesulfonic acid, tin methanesulfonate, silver methanesulfonate, and an organic additive containing sulfur. Specifically, it is preferable to use a silver-tin alloy plating solution having a methanesulfonic acid concentration of 40 g/L, an Ag concentration of more than 40 g/L and 90 g/L or less, and an Sn concentration of 5 to 35 g/L. . This silver-tin alloy plating solution does not contain cyanides such as silver cyanide, potassium silver cyanide, sodium cyanide and potassium cyanide. Also, the tin anode uses both Ag and Pt/Ti (platinum coated titanium plate) insoluble electrodes, the area of which is more than twice that of the cathode, and the current distribution between Ag and Pt/Ti is Ag : Pt/Ti=4:1 is preferred. Furthermore, the bath temperature is set to 40° C. to 60° C. and the current density is set to 1 to 15 A/dm ² to form the silver-tin alloy plating layer 5 .

[Silver plating layer forming step]
A silver plating layer 6 is formed on the silver-tin alloy plating layer 5 by applying silver plating. _The composition of the plating bath for this silver plating is not particularly limited. L, potassium carbonate (K ₂ CO ₃ ) 10 g/L to 20 g/L, and an organic additive that is easily incorporated into the plating layer, such as 2,2 thioethanol. Thioalcohols such as benzothiazoles, azoles such as benzotriazole, and imidazoles such as imidazole can be used. No cyanide baths based on methanesulfonic acid or potassium iodide can also be used.
Then, using a pure silver plate as an anode for this silver plating bath, silver plating is performed for 1 second to 7 minutes under the conditions of a bath temperature of 10° C. or higher and 40° C. or lower and a current density of 1 A/dm ² or higher and 10 A/dm ² or lower. A silver plating layer 6 is formed by applying to a certain extent.

Thus, the nickel plating layer 3 is formed on the surface of the base material 2, and the silver-tin alloy plating layer 5 and the silver plating layer 6 are sequentially formed on the intermediate plating layer 4 formed on at least a part of the surface. Pressing or the like is applied to the connector terminal material 1 thus formed to form a connector terminal in which a silver plating layer 6 is arranged on the surface of a portion used as a contact.

In this embodiment, since the silver plating layer 6 is formed on the surface, the surface is not easily oxidized even in a heating environment. Therefore, even after heating at 150° C. for 250 hours, the contact resistance is as low as 1 mΩ or less, and the heat resistance can be improved.
Since the silver-tin alloy plating layer 5 is formed, oxygen does not permeate from the surface layer, and peeling from the nickel plating layer 3 in the heating test can be suppressed. If the Ag content in the silver-tin alloy plating layer 5 is less than 70 at%, the contact resistance after heating decreases, and if the Ag content exceeds 85 at%, the grain size of the silver-tin alloy plating layer increases, resulting in a decrease in wear resistance. do.

In the embodiment, the intermediate plating layer 4, the silver-tin alloy plating layer 5, and the silver plating layer 6 are formed partially on the nickel plating layer 3 on the surface of the substrate 2. However, the terminal material of the present invention includes: Each plating layer may be laminated on the entire surface of the substrate 2 . The intermediate plated layer 4, the silver-tin alloy plated layer 5, and the silver plated layer 6 may be formed at least on a portion of the surface of the terminal material, specifically, on a portion that serves as a contact portion as a connector terminal.

A base material made of a copper alloy and having a thickness of 0.25 mm was plated with nickel to form a nickel plating layer having a thickness of 1.0 μm. An activation treatment was performed to clean the surface of the nickel plating layer using an aqueous solution. After this activation treatment, intermediate plating, silver strike plating, silver-tin alloy plating layer and silver plating layer were sequentially formed on the base material coated with the nickel plating layer to prepare each sample (samples 1 to 10). . At this time, the amount of Ag (g/L) and the amount of Sn (g/L) in the silver-tin alloy plating solution were the values shown in Table 1.

For comparison, samples were also produced without forming an intermediate plating layer on the nickel plating layer (Samples 19 to 21). These samples consisted only of a silver-tin alloy plated layer with a film thickness of 1 μm, without forming a silver-plated layer (sample 18), and a silver-tin alloy plated layer and a silver-plated layer with a film thickness of 0.5 μm each. (Sample 19), only a silver plating layer was formed with a thickness of 1 μm without forming a silver-tin alloy plating layer (Sample 20), and a silver alloy plating layer to which antimony was added was formed with a thickness of 1 μm (Sample 20). Sample 21).
In addition, the conditions of each plating were as follows.

<Nickel plating conditions>
・Plating bath composition Nickel sulfamate: 300 g / L
Nickel chloride: 30g/L
Boric acid: 30g/L
・Bath temperature: 45℃
・Current density: 3 A/dm ²

<Copper plating conditions>
・Plating bath composition Copper sulfate pentahydrate 250g/L
Sulfuric acid 50g/L
・Bath temperature: 50℃
・Current density: 3 A/dm ²
・Anode: Phosphorus-containing copper

<Palladium plating conditions>
・Plating bath composition Palladium chloride 17g/L
Ammonium phosphate 100ml/L
Ammonium chloride 25g/L
・Bath temperature: 30℃
・Current density: 1 A/dm ²
・Anode: Pt/Ti (Insoluble electrode made by coating a titanium plate with platinum)

<Cobalt plating conditions>
・Plating bath composition Cobalt sulfate heptahydrate 140g/L
Boric acid 40g/L
・Bath temperature: 30℃
・Current density: 1 A/dm ²
・Anode: Pt/Ti

<Manganese plating conditions>
・Plating bath composition manganese sulfate 200g/L
Ammonium sulfate 100g/L
・Bath temperature: 30℃
・Current density: 8 A/dm ²
・Anode: Pt/Ti

<Silver strike plating conditions>
・Plating bath composition Daiwa Kasei Co., Ltd. Daisilver use ・Bath temperature: 25 ° C
・Current density: 1 A/dm ²
Anode: Ir/Ti
(Insoluble electrode in which titanium plate is coated with iridium oxide (IrO ₂ ))

<Silver-tin alloy plating conditions>
・Plating bath composition methanesulfonic acid: 40 g / L
Tin methanesulfonate: 13-91g/L
Silver methanesulfonate: 75-170g/L
Organic additive: 5mg/L
・Bath temperature: 50℃
・Current density: 1 to 15 A/dm ²

<Silver plating conditions>
・Plating bath composition Potassium silver cyanide: 55 g / L
Potassium cyanide: 130g/L
Potassium carbonate: 15g/L
Nonionic surfactant: 1 g/L
2,2 thioethanol: 5 g/L
・Bath temperature: 25℃
・Current density: 5 A/dm ²
・Anode: pure silver plate

The antimony-containing silver alloy plating layer of sample 21 was produced by bright silver plating using Nissin Bright N bath containing antimony (manufactured by Nisshin Seisaku Co., Ltd.). A standard composition of the plating bath was used at a bath temperature of 25° C. and a current density of 5 A/dm ² , and a pure silver plate was used as the anode to form a silver alloy plating layer (AgSb alloy layer) having a thickness of 1 μm.

For the obtained sample, the Ag content in the silver-tin alloy plating layer, the thickness of the silver-tin alloy plating layer, and the thickness of the silver plating layer were measured, the thickness of the intermediate plating layer and the contact resistance were measured, and Abrasion resistance was evaluated.

[Ag content in silver-tin alloy plating]
A cross-sectional sample is prepared by processing the plated material with a focused ion beam device (FIB), and the Ag content (at%) in the silver-tin alloy plating is measured using an electron probe microanalyzer manufactured by JEOL Ltd.: EPMA (model number JXA-8530F) was used to measure the cross section of each sample at an acceleration voltage of 10 kV.

[Film thickness of each plating layer]
The plated material is processed with a focused ion beam device (FIB) to prepare a cross-sectional sample, the cross-sectional surface is observed with a scanning ion microscope (SIM), and the film thickness (μm) is measured from the obtained SIM image, The obtained numerical value was taken as the film thickness.

[Contact resistance]
Each sample before heating and each sample after heating at 150° C. for 250 hours were each cut into a test piece of 60 mm×10 mm. The sample was used as a substitute for the female terminal. The contact resistance (mΩ) was measured before heating and after heating at 150° C. for 250 hours. For the measurement, a friction wear tester (UMT-Tribolab) of Bruker AXS Co., Ltd. is used, the convex surface of the female test piece is brought into contact with the horizontally installed male terminal test piece, and the male terminal test piece is subjected to a load of 20N. The contact resistance value was measured by the 4-probe method when the pressure was applied.

[Abrasion resistance]
Each sample was cut into a test piece of 60 mm×10 mm, and the flat plate sample was used as a substitute for the male terminal, and the sample obtained by subjecting the flat plate sample to convex processing with a radius of curvature of 3 mm was used as a substitute for the female terminal. In the sliding test, a friction wear tester (UMT-Tribolab) manufactured by Bruker AXS Co., Ltd. is used, and the male terminal test piece placed horizontally is brought into contact with the convex surface of the female test piece, and a load of 2N is applied. Then, the male terminal test piece was slid horizontally at a moving distance of 5 mm and a sliding speed of 1 Hz. After the sliding test, the wear resistance was determined by whether or not the base (nickel layer) of the convex processed sample was exposed. At this time, the case where the substrate was not exposed after the sliding test was evaluated as "Good", and the case where the substrate was exposed after the sliding test was evaluated as "B".

These results are shown in Tables 1 and 2. "-" in the table indicates that plating was not carried out or film formation was not possible, so that measurement and evaluation were not carried out.

As is clear from Tables 1 and 2, the film thickness of the intermediate plating layer is 0.02 μm or more, the silver-tin alloy plating layer contains Ag in the range of 70 at % or more and 85 at % or less, and the silver-tin alloy Samples 1 to 4, 7, 8, 10, 11, and 13 to 17, in which the film thickness of the plating layer is 0.5 μm or more and 5 μm or less, have good contact resistance of 2 mΩ or less after heating and good wear resistance. there were. Among these, samples 8, 10, 11, and 13 to 17, in which a silver plating layer was formed on the outermost surface with a thickness of 0.1 μm or more and 2 μm or less, were samples 1 to 4, in which no silver plating layer was formed, and silver plating. Compared to Sample 7, which had a layer thickness of 0.1 μm, the contact resistance value after heating was lower, indicating that it is suitable for use in a heated environment.
FIG. 2 is a SIM image of sample 13. A layer made of Cu (represented as Cu) as an intermediate plating layer on a nickel plating layer (represented as Ni) on the surface of a base material (represented as Base Material), a silver-tin alloy A plated layer (denoted as AgSn) and a silver plated layer (denoted as Ag) are formed.
On the other hand, in sample 5, since the film thickness of the silver-tin alloy plating layer was as small as 0.4 μm, the wear resistance was inferior.
In sample 6, the Sn content in the silver-tin alloy plating layer is high (the Ag content is low), so the Sn diffused by heating forms an oxide film on the outermost layer, increasing the contact resistance.
Since the Ag content in the silver-tin alloy plating layer of sample 9 was 87 at %, the size of crystal grains in the silver-tin alloy plating layer was extremely varied, and a uniform film could not be formed.
Sample 12 was inferior in wear resistance because the film thickness of the intermediate plating layer was 0.01 μm.
Samples 18 to 21, in which no intermediate plating layer was formed, were inferior in wear resistance.

1 Terminal material for connector 2 Base material 3 Nickel plating layer 4 Intermediate plating layer 5 Silver-tin alloy plating layer 6 Silver plating layer

Claims (4)

A substrate having at least a surface made of copper or a copper alloy, a nickel plating layer formed on the surface of the substrate, an intermediate plating layer formed on the nickel plating layer, and a layer formed on the intermediate plating layer and a silver-tin alloy plating layer, wherein the intermediate plating layer contains any one of Pd , Co, and Mn as a main component, the thickness of the intermediate plating layer is 0.02 μm or more, and the A terminal material for a connector, wherein the silver-tin alloy plating layer contains Ag in a range of 70 at % or more and 85 at % or less, and the thickness of the silver-tin alloy plating layer is 0.5 μm or more and 5 μm or less. 2. The connector according to claim 1, wherein a silver plating layer made of Ag having a purity of 99% by mass or more is formed on the silver-tin alloy plating layer with a thickness of 0.1 μm or more and 2.0 μm or less. terminal material. 2. A connector terminal made of the connector terminal material according to claim 1, wherein the surface of the contact portion with the mating connector terminal is made of the silver-tin alloy plating layer. 3. A connector terminal made of the connector terminal material according to claim 2, wherein a surface of a contact portion with a mating connector terminal is formed of the silver plating layer.

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