JP2021063249A - Terminal material for connectors - Google Patents

Abstract

To provide a terminal material for connectors which has excellent heat resistance, improves wear resistance by preventing peeling, and is capable of keeping contact resistance low.SOLUTION: The terminal material for connectors includes: a substrate in which at least a surface layer is made of copper or a copper alloy; a ground layer formed on the substrate; and a silver layer formed on the ground layer, made of silver or a silver alloy, and having a film thickness of 0.5 μm or more and 15 μm or less. The ground layer contains nickel as a main component and has, at least at an interface with the silver layer, an Ni-SiC composite layer in which nickel and SiC particles are co-deposited. The amount of co-deposited SiC in the Ni-SiC composite layer is 0.1 mass% or more.SELECTED DRAWING: Figure 1

Description

The present invention relates to a terminal material for a connector provided with a useful film used for connecting electrical wiring of automobiles, consumer devices, and the like.

As the connector terminals used for connecting electrical wiring of automobiles and consumer equipment, terminal materials in which the surface of a copper or copper alloy base material is plated with tin, gold, silver or the like is generally used. Of these, terminal materials plated with precious metals such as gold and silver have excellent heat resistance and are therefore suitable for use in high-temperature environments. Further, in order to prevent the diffusion of Cu from the base material, the surface of the base material is often covered with a nickel layer made of nickel or a nickel alloy.
However, when the surface of the terminal material is a silver layer, silver is difficult to diffuse with nickel, so that the adhesion is poor and the wear resistance is impaired. In addition, oxygen that has entered from the surface of the silver layer in a high temperature environment may oxidize nickel and promote peeling of the silver layer from the nickel layer.

The techniques of Patent Documents 1 to 3 are disclosed in order to improve the adhesion of the terminal material for a connector.
In Patent Document 1 and Patent Document 2, an intermediate layer made of copper or a copper alloy controlled to have a predetermined arithmetic mean roughness Ra is provided between the base layer made of nickel or the like and the silver layer of the outermost layer. It is stated that good heat resistance, fretting resistance, and adhesion can be realized.
Further, Patent Document 3 describes that a silver-copper-containing alloy plating layer containing 0.5% by mass to 30% by mass of copper is formed on a base layer such as nickel.

Japanese Unexamined Patent Publication No. 2015-117424 JP-A-2010-146926 Japanese Unexamined Patent Publication No. 2011-231369

However, in these terminal materials for connectors described in the patent documents, Cu in the intermediate layer and the silver-copper-containing alloy plating layer may diffuse to the outermost surface and oxidize in a high temperature environment to increase the contact resistance.

The present invention has been made in view of such circumstances, and a terminal material for a connector which has excellent heat resistance, can prevent peeling, improve wear resistance, and can suppress contact resistance to a low level. The purpose is to provide.

The terminal material for a connector of the present invention is composed of a base material whose surface layer is at least copper or a copper alloy, a base layer formed on the base material, and silver or a silver alloy formed on the base layer. A silver layer having a thickness of 0.5 μm or more and 15 μm or less is provided, and the base layer contains nickel as a main component, and Ni-SiC formed by co-depositing nickel and SiC particles at least at the interface with the silver layer. It has a composite layer, and the Ni—SiC composite layer has an elution amount of the SiC of 0.1% by mass or more.

Since the surface of the terminal material for a connector of the present invention is composed of a silver layer having excellent heat resistance, and the silver layer is formed on the surface of the Ni-SiC composite layer of the base layer, the Ni-SiC composite layer The SiC particles inside exert an anchor effect on the silver layer and improve the adhesion with the silver layer. Therefore, it is possible to prevent the silver layer from peeling off and improve the wear resistance. If the amount of SiC coagulated in the SiC composite layer is less than 0.1% by mass, a sufficient anchoring effect cannot be exhibited and peeling of the silver layer cannot be prevented. Further, since the base layer contains nickel as a main component, it is possible to prevent the diffusion of Cu from the base material and suppress the contact resistance of the silver layer to a low level.
If the film thickness of the silver layer is less than 0.5 μm, the silver layer disappears at an early stage due to slight sliding wear of the connector terminal and the insertion / removal operation, so that the electrical connection reliability cannot be ensured. There is no problem if the silver layer has a film thickness of more than 15 μm, but even if it is made thicker than this, the effect of improving heat resistance is saturated.

In one embodiment of the terminal material for a connector, the base layer is composed of a nickel layer made of nickel or a nickel alloy covering the surface of the base material, and the Ni-SiC composite layer formed on the nickel layer. The thickness of the nickel layer is 0.2 μm or more and 3.0 μm or less, the thickness of the Ni—SiC composite layer is 0.1 μm or more and 2.0 μm or less, and the amount of eutectoid of the SiC particles is It is 8.0% by mass or less.

By evaporating the SiC particles in the Ni—SiC composite layer with the above average particle size and elution amount, the anchor effect can be appropriately exhibited. When the amount of eutectoid of SiC particles exceeds 8.0% by mass, the Ni—SiC composite layer becomes brittle.

If the film thickness of the Ni—SiC composite layer is less than 0.1 μm, SiC is unlikely to be co-deposited in the layer, and a sufficient anchoring effect may not be obtained. If the film thickness of the Ni—SiC composite layer exceeds 2.0 μm, cracks are likely to occur during processing.
This base layer has a multi-layer structure of a nickel layer covering the surface of the base material and a Ni-SiC composite layer, and since the thickness of the Ni-SiC composite layer is 0.1 μm or more, diffusion of Cu from the base material For prevention, the thickness of the nickel layer is preferably 0.2 μm or more. In this case, the thickness of the nickel layer is sufficient to be 3.0 μm in order to prevent the diffusion of Cu, and if it is thicker than this, cracks are likely to occur during processing.
The average particle size of the SiC particles is not necessarily less than or equal to the film thickness of the Ni—SiC composite layer, and includes those that slightly protrude from the surface of the Ni—SiC composite layer.

In another aspect of the terminal material for the connector, the base layer is made of the Ni-SiC composite layer, the film thickness is 0.4 μm or more and 3.0 μm or less, and the eutectoid amount of the SiC particles is 3.0. It is less than mass%.

In this embodiment, the base layer is only a Ni—SiC composite layer, and the base layer can be formed by a single plating process. In this case, since it does not have a nickel layer, the film thickness of the Ni—SiC composite layer is preferably 0.4 μm or more in order to prevent Cu diffusion from the base material. On the other hand, if the film thickness of the Ni—SiC composite layer exceeds 3.0 μm, cracks are likely to occur during processing.

According to the present invention, it has excellent heat resistance, prevents peeling, improves wear resistance, and can suppress contact resistance low.

It is sectional drawing which shows typically the terminal material for a connector which concerns on 1st Embodiment of this invention. It is sectional drawing which shows typically the terminal material for a connector which concerns on 2nd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a first embodiment, and FIG. 2 shows a second embodiment.

<First Embodiment>
[Structure of terminal material for connector]
The connector terminal material 1 of the first embodiment is formed on a plate-shaped base material 2 having at least a surface layer made of copper or a copper alloy and an upper surface of the base material 2, as schematically shown in the cross section in FIG. The base layer 3 is provided with a silver layer 4 made of silver or a silver alloy formed on the base layer 3.

The composition of the surface layer of the base material 2 is not particularly limited as long as it is made of copper or a copper alloy. In the present embodiment, as shown in FIG. 1, the base material 2 is made of a plate material made of copper or a copper alloy, but is made of a plating material having copper plating or copper alloy plating on the surface of the base material. You may. In this case, oxygen-free copper (C10200), Cu—Mg-based copper alloy (C18665), or the like can be applied as the base material.

The base layer 3 contains nickel as a main component, and has a function of suppressing the diffusion of Cu from the base material 2 into the silver layer 4 formed on the base layer 3.
In this first embodiment, the base layer 3 has a two-layer structure consisting of a nickel layer 5 made of nickel or a nickel alloy and a Ni—SiC composite layer 6 formed on the nickel layer 5.
The nickel layer 5 is coated by applying nickel plating made of nickel or a nickel alloy on the base material 2. Therefore, of the base layer 3, the nickel layer 5 is formed at the interface with the base material 2. The film thickness of the nickel layer 5 is 0.2 μm or more and 3.0 μm or less.
The base layer 3 of the first embodiment has a two-layer structure of a nickel layer 5 and a Ni-SiC composite layer 6, and the lower limit of the film thickness of the Ni-SiC composite layer 6 is 0.1 μm as described later. The thickness of the nickel layer 5 is preferably 0.2 μm or more in order to prevent the diffusion of Cu from the base material 2. The upper limit of the film thickness of the nickel layer 5 is 3.0 μm, and if it is thicker than this, cracks are likely to occur during processing. The composition of the nickel layer 5 is not particularly limited as long as it is made of nickel or a nickel alloy.

The Ni—SiC composite layer 6 is formed at the interface with the silver layer 4 of the base layer 3. The Ni-SiC composite layer 6 is formed by evaporating (dispersing) nickel (Ni) and SiC particles, and the SiC particles 61 in the Ni-SiC composite layer 6 exert an anchor effect on the silver layer 4. It exerts its effect and improves the adhesion with the silver layer 4. Therefore, it is possible to prevent the silver layer 4 from peeling off and improve the wear resistance. Further, since the Ni—SiC composite layer 6 contains a large amount of nickel, it has an effect of preventing the diffusion of Cu from the base material 2 as in the nickel layer 5, and the contact resistance of the silver layer 4 can be suppressed low. ..

The Ni—SiC composite layer 6 has a film thickness of 0.1 μm or more and 2.0 μm or less, and an elution amount of SiC particles of 0.1% by mass or more and 8.0% by mass or less.
If the film thickness of the Ni—SiC composite layer 6 is less than 0.1 μm, the anchor effect on the silver layer 4 becomes poor because it is too thin, and the silver layer 4 is easily peeled off. If the film thickness of the Ni—SiC composite layer 6 exceeds 2.0 μm, cracks are likely to occur during processing. If the elution amount of the SiC particles 61 is less than 0.1% by mass, it is difficult to obtain a sufficient anchor effect, and if the eutectoid amount of the SiC particles exceeds 8.0% by mass, the Ni—SiC composite layer 6 becomes brittle. Become. Here, the amount of eutectoid of SiC particles refers to the mass ratio of SiC particles contained in the Ni—SiC composite layer.
The average particle size of the SiC particles 61 is preferably 90 nm or more and 300 nm or less, and if it is less than 90 nm, a sufficient anchoring effect may not be obtained. Is difficult to be incorporated into the nickel plating layer, and eutectoidation is difficult, so that the desired Ni—SiC composite layer 6 may not be obtained. Further, the average particle size of the SiC particles 61 is not necessarily equal to or less than the film thickness of the Ni—SiC composite layer 6, and includes particles that slightly protrude from the surface of the Ni—SiC composite layer 6.

The silver layer 4 is made of silver or a silver alloy and has an effect of increasing heat resistance. In the case of a silver alloy, the hardness of the silver layer 4 is increased and the wear resistance is excellent.

The film thickness of the silver layer 4 is 0.5 μm or more and 15 μm or less. If the film thickness of the silver layer 4 is less than 0.5 μm, the silver layer 4 disappears at an early stage due to slight sliding wear of the connector terminal and the insertion / removal operation, so that the electrical connection reliability cannot be ensured. There is no problem even if the silver layer 4 has a film thickness of more than 15 μm, but it causes an increase in cost.

Next, a method of manufacturing the terminal material 1 for the connector will be described. The method for manufacturing the terminal material 1 for a connector includes a pretreatment step of cleaning a plate material whose surface layer is at least copper or a copper alloy, which is a base material 2, and nickel plating of nickel or a nickel alloy on the surface of the base material 2. A nickel plating step of forming a nickel layer 5 and a Ni-SiC composite plating step of forming a Ni-SiC composite layer 6 from a nickel plating bath in which SiC particles are dispersed on the nickel layer 5 and a Ni-SiC composite layer 6 It is provided with a silver plating step of performing silver strike plating on the surface and then performing silver plating made of silver or a silver alloy.

[Pretreatment process]
First, as the base material 2, a plate material whose surface layer is at least made of copper or a copper alloy is prepared, and the surface is cleaned by degreasing, pickling, or the like.

[Nickel plating process]
The surface of the base material 2 is plated with nickel or a nickel alloy to form the nickel layer 5. For example, it is formed by performing nickel plating under the conditions of ^{a bath temperature of 45 ° C. and a current density of 3 A / dm 2} using a nickel plating bath composed of nickel sulfamate 300 g / L, nickel chloride 30 g / L, and boric acid 30 g / L. Will be done. The nickel plating 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.

[Ni-SiC composite plating process]
The surface of the nickel layer 5 formed on the base material 2 is activated with a 5% by mass to 10% by mass sulfuric acid aqueous solution, and then a Ni—SiC composite layer is formed.
The plating bath for this Ni-SiC composite plating is not particularly limited to a bath type, but a watt bath and a sulfamic acid bath are preferable. The SiC particles dispersed in the plating bath have an average particle size of 90 nm or more and 300 nm or less, and have a content of 0.2 g / L or more and 15 g / L or less with respect to the plating solution.

[Silver plating process]
The silver plating treatment step includes a silver strike plating treatment in which silver strike plating is performed on a Ni-SiC composite layer, and a silver plating treatment in which silver plating made of silver or a silver alloy is subsequently performed.

(Silver strike plating process)
First, the Ni-SiC composite layer 6 is activated with 5 to 10% by mass of an aqueous potassium hydroxide solution, and then the Ni-SiC composite layer 6 is subjected to short-time silver strike plating to make it thin. Form a silver-plated layer. This silver strike plating is applied to enhance the adhesion with the Ni—SiC composite layer. The composition of the plating bath for applying the silver strike plating may be either a cyanide bath or a no-cyanide bath, and is not particularly limited. For example, silver cyanide (AgCN) 1 g / L to 5 g / L and potassium cyanide (KCN) 80 g. A plating bath consisting of / L to 120 g / L is suitable. Then, using stainless steel (SUS316) as an anode for this silver plating bath, silver strike plating is performed for about 30 seconds under the conditions of a bath temperature of 25 ° C. to 30 ° C. and a current density of 1 A / dm ^2. Layers are formed. If the silver-plated layer is subsequently formed, the silver-strike-plated layer becomes difficult to identify as a layer.

(Silver plating)
After silver strike plating, silver plating made of silver or a silver alloy is applied to form a silver plating layer. The composition of the plating bath for forming the silver plating layer is, for example, silver cyanide (AgCN) 30 g / L to 50 g / L and potassium cyanide (KCN) 100 g / L to 150 g in the case of silver antimony alloy plating. It consists of / L, potassium carbonate (K ₂ CO ₃ ) 15 g / L to 40 g / L, and an additive (Nissin Bright K manufactured by Nikkei Seisei Co., Ltd.) 10 g / L to 20 g / L.
Then, a silver plating layer is formed by performing silver plating on this plating bath using a pure silver plate as an anode under the conditions of a bath temperature of 25 ° C. and a current density of 4 A / dm ^{2 to} 12 A / dm ^{2, and silver is formed.} A silver layer 4 having a film thickness of 0.5 μm or more and 15 μm or less is formed integrally with the strike plating layer.

By performing nickel plating, Ni-SiC composite plating, and silver plating on the base material 2 in this way, a nickel layer 5, a Ni-SiC composite layer 6, and a silver layer 4 are formed on the surface of the base material 2. The terminal material 1 for the connector is formed. Then, by performing press working or the like on the connector terminal material 1, a connector terminal in which the silver layer 4 is located is formed on the surface.

Since the outermost surface of the connector terminal material 1 of the present embodiment is formed by the silver layer 4, it is excellent in heat resistance. In this case, if the film thickness of the silver layer 4 is less than 0.5 μm, the silver layer disappears at an early stage due to slight sliding wear of the connector terminal and the insertion / removal operation, so that the electrical connection reliability cannot be ensured. There is no problem even if the silver layer 4 has a film thickness of more than 15 μm, but it causes an increase in cost.

Further, since the SiC particles 61 are dispersed in the Ni-SiC composite layer 6 under the silver layer 4, the surface of the Ni-SiC composite layer 6 has irregularities, which exerts an anchor effect to form the silver layer 4 and the silver layer 4. The adhesion of is improved.
Further, since the surface of the base material 2 is covered with the nickel layer 5 and the Ni-SiC composite layer 6 is formed on the nickel layer 5, the base layer 3 composed of the nickel layer 5 and the Ni-SiC composite layer 6 is used. It is possible to prevent the diffusion of Cu from the base material 2 and improve the heat resistance.

<Second Embodiment>
FIG. 2 shows a terminal material for a connector according to a second embodiment of the present invention. In the terminal material 11 for a connector, a base layer 31 containing nickel as a main component is formed on the base material 2, and a silver layer 4 made of silver or a silver alloy is formed on the base layer 31. Similar to the first embodiment, but the first embodiment is that the base layer 31 is composed of only the Ni—SiC composite layer 6 formed by co-depositing nickel and SiC particles and does not have the nickel layer 5. Is different from.

In this case, in the Ni-SiC composite layer 6, the average particle size of the SiC particles is 90 nm or more and 300 nm or less, and the eutectoid amount of the SiC particles is 0.1% by mass or more and 3.0% by mass, as in the case of the first embodiment. It is as follows. However, the film thickness of the Ni—SiC composite layer 6 is 0.4 μm or more and 3.0 μm or less. In the first embodiment, the base layer 3 is composed of the nickel layer 5 and the Ni—SiC composite layer 6, but in the second embodiment, the base layer 31 is composed of only the Ni—SiC composite layer 6, so that the base material is used. In order to prevent the diffusion of Cu from 2, the thickness of the Ni—SiC composite layer 6 is preferably 0.4 μm or more. It is useless that the film thickness of the Ni-SiC composite layer exceeds 3.0 μm because the SiC particles to be co-deposited also have a large particle size and require a large amount. Since the amount of SiC coagulated does not have the nickel layer 5 as in the first embodiment, the effect of preventing the diffusion of Cu from the base material 2 is reduced and cracks are likely to occur during processing. , 3.0% by mass or less is preferable.

When the connector terminal material 11 of the second embodiment is manufactured, the nickel plating step is omitted from the manufacturing method of the first embodiment. That is, the Ni—SiC composite layer 6 is formed from a pretreatment step of cleaning a plate material whose surface layer is at least copper or a copper alloy as the base material 2 and a nickel plating bath in which SiC particles are dispersed on the surface of the base material 2. It includes a Ni-SiC composite plating step and a silver plating step of performing silver strike plating on the Ni-SiC composite layer 6 and then silver plating made of silver or a silver alloy. The details of each step are the same as those of the first embodiment except for the plating film thickness in the Ni—SiC composite plating step.

In the connector terminal material 11 of the second embodiment, since the base layer 31 is composed only of the Ni—SiC composite layer 6, the number of manufacturing steps is reduced and labor is saved because the nickel plating step is not provided.

In addition, the detailed configuration is not limited to the configuration of the embodiment, and various changes can be made without departing from the gist of the present invention. For example, in the above embodiment, the base layers 3, 31 and the silver layer 4 are formed on the entire upper surface of the base material 2, but the base layer 3 and the silver layer 4 are formed on a part of the surface of the base material 2. The silver layer 4 may be formed on a part of the upper surfaces of the base layers 3 and 31 formed on the entire upper surface of the base material 2. Further, even when the base layer 3 has a multi-layer structure of the nickel layer 5 and the Ni—SiC composite layer 6 as in the first embodiment, the nickel layer 5 is formed over the entire upper surface of the base material 2, and the nickel thereof is formed. A Ni-SiC composite layer 6 may be formed on a part of the upper surface of the layer 5, and a silver layer 4 may be formed on the Ni-SiC composite layer 6. It suffices that the surface of at least the portion that becomes a contact when formed on the terminal is the silver layer 4.

A base material having a thickness of 0.3 mm made of a copper alloy plate is prepared, and the base material is pretreated to clean the surface by degreasing, pickling, etc., and then a base layer is formed on the surface of the base material. did. Two types of base layers were prepared, one in which only the Ni-SiC composite layer was formed and the other in which the Ni-SiC composite layer was formed after the nickel layer was formed. Then, an activation treatment for cleaning the surface of the base layer was performed using a 5% by mass potassium hydroxide aqueous solution. After this activation treatment, the base material coated with the base layer was subjected to a silver strike plating treatment and then a silver plating treatment. Further, for comparison, a nickel layer was formed without forming a Ni—SiC composite layer as a base layer, and a silver layer was formed on the nickel layer (Sample 13).

The conditions for each plating were as follows.
<Nickel plating conditions>
-Plating bath composition Nickel sulfamate: 300 g / L
Nickel chloride: 30 g / L
Boric acid: 30 g / L
・ Anode: Nickel plate ・ Bath temperature: 45 ℃
-Current density: 3A / dm ²

<Ni-SiC composite plating conditions>
-Plating bath composition Nickel sulfamate: 300 g / L
Nickel chloride: 30 g / L
Boric acid: 30 g / L
SiC particles (average particle size are listed in Table 1): 0.2 g / L to 15 g / L
・ Anode: Nickel plate ・ Bath temperature: 45 ℃
・ Current density: 5A / dm ²

<Silver strike plating conditions>
-Plating bath composition Silver cyanide: 2 g / L,
Potassium cyanide: 100 g / L
・ Anode: Stainless steel (SUS316) plate ・ Bath temperature: 25 ℃
・ Current density: 1A / dm ²

<Silver plating conditions>
-Plating bath composition Silver cyanide potassium: 55 g / L
Potassium cyanide: 150 g / L
Potassium carbonate: 20 g / L
Brightener (Nissin Bright K manufactured by Nikkei Seisei Co., Ltd.): 15 ml / L
・ Anode: Pure silver plate ・ Bath temperature: 25 ℃
・ Current density: 5A / dm ²

For each sample, the thickness of each of the nickel layer, Ni-SiC composite layer, and silver layer, the amount of segregation of SiC particles in the Ni-SiC composite layer, and the average particle size of SiC particles were measured, and the abrasion resistance and after heating were measured. The degree of discoloration was evaluated.

[Measurement of film thickness of nickel layer, Ni-SiC composite layer, silver layer]
The thickness of each layer is determined by cross-section processing using a focused ion beam device: FIB (model number: SMI3050TB) manufactured by Seiko Instruments Co., Ltd., and at any three locations in a cross-section SIM (Scanning Ion Microscope) image with an inclination angle of 60 °. After measuring the length of the film and calculating the average, it was converted to the actual length.
In the Ni-SiC composite layer, when a part of the SiC particles protrudes from the surface of the layer, the protruding portion is not measured when measuring the film thickness, and the SiC particles are buried in the layer. The part was measured.

[Amount of segregation of SiC particles]
Using a pressurized acid decomposition apparatus, the film of the Ni—SiC composite layer was dissolved together with the SiC particles and made into a solution. The solution was measured with a high-resolution ICP (inductively coupled plasma) emission spectrophotometer (model number: PS-3500DD) manufactured by Hitachi High-Tech Science Corporation, and the amount of eutectoid (mass%) of SiC particles was determined.

[Average particle size of SiC particles]
The average particle size of the SiC particles is the particle size when mixed in the plating solution. For the measurement of this average particle size, the particle size distribution was measured by the dynamic light scattering method using a dynamic light scattering particle size distribution measuring device (manufactured by Malvern), and the average particle size was calculated from the distribution.
Even if the SiC particles in the plating solution are co-deposited in the Ni—SiC composite layer, the particle size of the SiC particles does not change.

[Abrasion resistance]
Each sample was cut into a test piece of 60 mm × 10 mm, and a flat plate sample was used as a substitute for a male terminal, and a sample obtained by subjecting this flat plate sample to a convex processing with a radius of curvature of 3 mm was used as a substitute for a female terminal. The wear resistance was evaluated by the following sliding test. In this vibration test, a friction and wear tester (UMT-Tribolab) manufactured by Bruker AXS Corporation was used, and the convex surface of the female test piece was brought into contact with the horizontally installed male terminal test piece, and a load of 5N was applied. Then, the male terminal test piece was slid horizontally by 10 mm. Abrasion resistance was determined based on whether or not the underlying layer (Ni—SiC composite layer or nickel layer) of the silver layer of the convex processed sample was exposed after sliding. At this time, "A" is the one in which the base layer is not exposed after the sliding test, "B" is the one in which the base layer is exposed but less than half of the sliding marks, and more than half of the sliding marks. The one with the base layer exposed was designated as "C".

[Degree of discoloration after heating]
After heating the sample at 150 ° C. for 500 hours, the surface was visually inspected for loss of silver luster. The one determined to have no loss of silver luster was designated as "A", and the one determined to have no loss of silver luster was designated as "B".

These results are shown in Tables 1 and 2. The notation "-" indicates that the corresponding layer was not formed.

In Table 1, Sample 5 shows that the SiC particles having the average particle size shown in the table were dispersed in the plating solution and plated, but none of the formed plating films was co-deposited with Ni.
As can be seen from Table 1, Samples 4, 6 to 12, 14 have a wear resistance of "A" or higher and a discoloration after heating of "B" or higher, and have sufficient wear resistance and heat resistance for practical use. Have. Since the total film thickness of the sample 4 and the sample 11 as the base layer was as small as 0.3 μm, it is considered that the discoloration after heating was evaluated as “B”.

On the other hand, in Sample 1, the film thickness of the silver layer was as small as 0.3 μm, so that the wear resistance was inferior. Sample 2 has a sufficient film thickness as a base layer having a two-layer structure of a nickel layer and a Ni-SiC composite layer, but the amount of SiC coagulation in the Ni-SiC composite layer is as small as 0.05% by mass. In the sliding test, the silver layer was peeled off and the underlying layer was exposed. Sample 3 was also evaluated as having low wear resistance because the amount of segregation of SiC particles was 0.05% by mass. As described above, the sample 5 was inferior in wear resistance because the SiC particles were not co-deposited. It is recognized that this is because the particle size of the SiC particles dispersed in the plating solution was too large compared to the film thickness formed as the Ni—SiC composite layer, and therefore no coagulation was performed.
In Sample 13, a silver layer was directly formed on the nickel layer without forming a Ni—SiC composite layer, but the underlying nickel layer was exposed in the sliding test, and the abrasion resistance was inferior. ..

1,11 Connector terminal material 2 Base material 3 Base layer 4 Silver layer 5 Nickel layer 6 Ni-SiC composite layer 61 SiC particles

Claims (3)

At least a base material whose surface layer is made of copper or a copper alloy, a base layer formed on the base material, and a silver or silver alloy formed on the base layer, having a film thickness of 0.5 μm or more and 15 μm or less. With a silver layer,
The base layer contains nickel as a main component, and has a Ni-SiC composite layer formed by co-depositing nickel and SiC particles at least at an interface with the silver layer, and the Ni-SiC composite layer is said to have the same. A terminal material for a connector, characterized in that the amount of SiC coagulated is 0.1% by mass or more. The base layer is composed of a nickel layer made of nickel or a nickel alloy covering the surface of the base material and the Ni—SiC composite layer formed on the nickel layer, and the thickness of the nickel layer is 0. The Ni-SiC composite layer is 2 μm or more and 3.0 μm or less, the thickness of the Ni-SiC composite layer is 0.1 μm or more and 2.0 μm or less, the average particle size of the SiC particles is 90 nm or more and 300 nm or less, and the eutectoid of the SiC particles. The terminal material for a connector according to claim 1, wherein the amount is 8.0% by mass or less. The base layer is composed of the Ni-SiC composite layer, the film thickness is 0.4 μm or more and 3.0 μm or less, the average particle size of the SiC particles is 90 nm or more and 300 nm or less, and the eutectoid amount of the SiC particles is 3. The terminal material for a connector according to claim 1, wherein the content is 0% by mass or less.

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