WO2024062909A1

WO2024062909A1 - Terminal material and terminal

Info

Publication number: WO2024062909A1
Application number: PCT/JP2023/032243
Authority: WO
Inventors: 将嘉鶴; 慎太郎山本; 翔生桂; 弘高伊藤; 貴之湖山
Original assignee: 株式会社神戸製鋼所
Priority date: 2022-09-22
Filing date: 2023-09-04
Publication date: 2024-03-28
Also published as: TW202413732A; JP7459202B1; JP2024048406A; JP2024050638A

Abstract

This terminal material comprises, in the following order, a base material which comprises copper or a copper alloy, one or more underlayers which are constituted by one or more element selected from the group consisting of Ni, Co, and Fe, and a silver-containing film. The silver-containing film includes a silver plating layer which contains not less than 50 mass% silver, and particles which comprise a non-conductive organic compound and which have a circle-equivalent diameter in contact with the silver plating layer of not more than 50 μm. When the following fretting test is performed, the contact resistance of the silver-containing-film-side surface is not more than 1 mΩ. Fretting test: Prepared are the terminal material which is to be tested and a counterpart material, in which is formed a hemispherical protrusion having a curvature radius R of 1.8 mm with respect to the silver-containing-film-side surface of the terminal material. The surface of the counterpart material which has the protrusion is caused to slide for 10,000 cycles against the silver-containing-film-side surface of the terminal material to be tested, wherein one cycle involves sliding back and forth with an applied vertical load of 3N, a sliding distance of 50 μm, and a sliding speed of 100 μm/second.

Description

Terminal materials and terminals

The present disclosure relates to terminal materials and terminals.

As automobiles become lighter in recent years, there is a need to reduce the amount of wire harnesses used in automobiles. For example, wiring harnesses can be reduced by directly connecting devices such as engines and motors to electronic components (referred to as "ECU") that control them.

Equipment such as engines and motors vibrate violently, so the connectors used to connect them and the terminals that make them up are exposed to violent vibration. Vibration can cause micro-friction wear in the terminals (i.e., the phenomenon in which repeated tiny friction wears away the plating on the contacts). In recent years, the miniaturization of terminals has led to a decrease in contact pressure and a worsening vibration environment, further increasing the likelihood of micro-friction wear occurring.

To deal with slight sliding wear, Patent Document 1 roughens the copper alloy base material, performs Ni plating, Cu plating, and Sn plating thereon, and performs reflow treatment to form a predetermined Cu-Sn layer. A technique for exposing the surface of the Sn layer is disclosed. Although this technique makes it difficult for micro-sliding wear to occur, once micro-sliding wear occurs, it may easily lead to material exposure.

In order to improve wear resistance, application of an Ag plating film is also being considered. Since ancient times, the aim has been to improve the wear resistance by increasing the hardness of the Ag plating film.
(1) Increasing the hardness of the Ag plating film through grain refinement (2) Increasing the hardness by alloying Ag with Se (selenium), Sb (antimony), etc. is being investigated. However, both methods (1) and (2) are insufficiently effective against slight sliding wear. Further, Se and Sb are toxic elements that require careful management, and there is also the problem that conductivity decreases as they are alloyed.

In addition, various improvements in wear resistance based on ideas other than increasing the hardness of the plating film have been investigated, mainly as disclosed in Non-Patent

Documents

1 and 2.
(3) Studies are also being conducted to improve wear resistance by eutectoiding (dispersion plating) carbon-based particles into the Ag plating film. These studies have mainly used graphite, carbon black (CB), or carbon nanotubes (CNT), which act as solid lubricants. In fact, in Non-Patent Document 1, a comparison was made not only with Ag plating films but also with hard Ag-Sb alloy plating films using an Ag-graphite composite plating film that was plated by suspending graphite particles in an Ag plating solution. It has been shown that good wear resistance can be achieved even if

JP2014-208904

In the prior art related to (3) above as disclosed in

Non-Patent Documents

1 and 2, when carbon particle dispersion plating is applied to the terminal material and sliding (insertion and removal) is repeated, the plating film will break down as the contact portion wears. The carbon particles held in the carbon particles may fall off. Since carbon-based particles have good electrical conductivity, if they fall off the terminal surface and accumulate around the contacts, they may cause a short circuit in the contacts. Further, the prior art related to (3) above may not be able to sufficiently suppress slight sliding wear.

This disclosure has been made in light of these circumstances, and one of its objectives is to provide a terminal material and terminal that can adequately suppress short circuits at the contacts due to the falling off of conductive particles, and that has sufficient resistance to fretting wear and conductivity.

Aspect 1 of the present invention is
A base material made of copper or a copper alloy, a base layer which is one or more layers made of one or more selected from the group consisting of Ni, Co and Fe, and a silver-containing film, in this order,
The silver-containing film includes a silver plating layer containing 50% by mass or more of silver, and particles made of a non-conductive organic compound with an equivalent circle diameter of 50 μm or less that are in contact with the silver plating layer,
The terminal material has a contact resistance of 1 mΩ or less on the silver-containing film side surface when subjected to the following micro-sliding abrasion test.

Micro-sliding wear test: Prepare the terminal material to be tested and a mating material in which a hemispherical protrusion with a radius of curvature R = 1.8 mm is formed on the surface of the terminal material on the silver-containing film side. The surface having the projections of the mating material is reciprocated by applying a vertical load of 3 N, sliding distance: 50 μm, and sliding speed: 100 μm/sec against the silver-containing film side surface of the terminal material to be tested. One cycle is sliding for 10,000 cycles.

Aspect 2 of the present invention is
The terminal material according to aspect 1, wherein the silver plating layer contains 90% by mass or more of silver.

Aspect 3 of the present invention is
The terminal material according to

aspect

1 or 2, wherein the non-conductive organic compound contains a carbonyl group (-C(=O)-) in a unit molecule structure and does not have a ring structure.

Aspect 4 of the present invention is
A terminal using the terminal material according to any one of aspects 1 to 3.

According to the embodiments of the present invention, it is possible to provide a terminal material and a terminal that can sufficiently suppress short-circuiting of contacts due to shedding of conductive particles and have sufficient micro-sliding wear resistance and conductivity. .

FIG. 1 is a schematic cross-sectional view of an example of a terminal material according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of another example of a terminal material according to an embodiment of the present invention. FIG. 3 is a schematic cross-sectional view of another example of the terminal material according to the embodiment of the present invention. FIG. 1 shows the results of micro-sliding wear resistance evaluation of terminal material No. 1. FIG. 2 shows the results of the micro-sliding wear resistance evaluation of the terminal material No. 2. FIG. These are the results of the micro-sliding wear resistance evaluation of the terminal material No. 3. FIG. This is the result of evaluating the slight sliding wear resistance of the terminal material No. 4. FIG. 5 shows the results of micro-sliding wear resistance evaluation of terminal material No. 5. FIG. These are the results of the micro-sliding wear resistance evaluation of the terminal material No. 6.

The present inventors investigated from various angles in order to realize a terminal material that can sufficiently suppress short-circuiting of contacts due to shedding of conductive particles and has sufficient micro-sliding wear resistance and conductivity. As a result, a predetermined layer structure having a silver plating layer and a silver-containing film containing particles made of a non-conductive organic compound with an equivalent circle diameter of 50 μm or less, which are in contact with (supported by) the silver plating layer, is formed. It has been found that sufficient micro-sliding wear resistance and electrical conductivity can be obtained by this method. This is because, due to slight sliding (and the heat generated by it), for example, a part of the non-conductive organic compound decomposes and diffuses to the vicinity of the terminal material surface, and/or a part of the non-conductive organic compound This is thought to be due to the fact that it reacts with the silver plating layer near the surface of the terminal material and lowers the coefficient of friction near the surface of the terminal material, thereby increasing micro-sliding wear resistance. Note that the decomposed products and reactants are small amounts and are considered not to reduce the conductivity of the terminal material. In addition, since the non-conductive organic compound is in contact with the silver plating layer in the form of particles rather than a film, the silver plating layer can be exposed on the surface of the terminal material, so it maintains the initial conductivity as a terminal material. can.
As a result of the above, it was possible to sufficiently suppress the risk of short-circuiting of contacts due to shedding of conductive particles, and to realize a terminal material having sufficient micro-sliding wear resistance and conductivity.
Note that the above mechanism does not limit the technical scope of the embodiments of the present invention.

Details of each requirement defined by the embodiment of the present invention are shown below.

The terminal material according to the embodiment of the present invention includes a base material made of copper or a copper alloy, and a base layer that is one or more layers made of one or more selected from the group consisting of Ni, Co, and Fe. , a silver-containing film in this order, and the silver-containing film is made of a silver plating layer containing 50% by mass or more of silver, and a non-conductive organic compound having an equivalent circle diameter of 50 μm or less that is in contact with the silver plating layer. The contact resistance of the silver-containing film side surface is 1 mΩ or less when subjected to the following micro-sliding abrasion test.
Micro-sliding wear test: Prepare the terminal material to be tested and a mating material in which a hemispherical protrusion with a radius of curvature R = 1.8 mm is formed on the surface of the terminal material on the silver-containing film side. The surface having the projections of the mating material is reciprocated by applying a vertical load of 3 N, sliding distance: 50 μm, and sliding speed: 100 μm/sec against the silver-containing film side surface of the terminal material to be tested. One cycle is sliding for 10,000 cycles.
As a result of the above, it is possible to sufficiently suppress short-circuiting of contacts due to shedding of conductive particles, and to exhibit sufficient micro-sliding wear resistance and conductivity.

FIG. 1 shows a schematic cross-sectional view of an example of a terminal material according to an embodiment of the present invention. In FIG. 1, a terminal material 1 includes a base material 2 made of copper or a copper alloy (hereinafter sometimes simply referred to as "base material 2") and one material selected from the group consisting of Ni, Co, and Fe. The base layer 3, which is one or more layers composed of the above, and the silver-containing film 4 are included in this order, and the silver-containing film 4 has a silver plating layer 4a and a circle equivalent diameter in contact with (adhering to) the silver plating layer 4a. particles 4b (hereinafter sometimes simply referred to as "particles 4b") made of a non-conductive organic compound and having a diameter of 50 μm or less. The terminal material 1 has a contact resistance of 1 mΩ or less on the surface of the silver-containing film 4 when subjected to the above-mentioned micro-sliding abrasion test.

In addition to pure copper such as oxygen-free copper (OFC), one or more of copper alloys such as CuFeP, CuNiSi, CuTiCr, CuSnP, and CuMg may be used as the material for the base material 2. Note that the properties required for the terminal material (electrical conductivity, springiness, strength, etc.) differ depending on the location of use. Therefore, the material of the base material 2 (and its refining conditions) can be appropriately selected depending on the required characteristics.

The terminal material 1 including the base material 2 (and a terminal using the same) can be used in a high-temperature environment, such as in the engine room of an internal combustion engine or in a connecting part of an electric vehicle battery. In a high-temperature environment, Cu in the base material 2 diffuses toward the silver-containing film 4 and reaches the surface of the silver-containing film 4, which may further generate Cu oxides and increase the contact resistance of the terminal material 1.
Therefore, between the base material 2 and the silver-containing film 4, a base layer 3, which is one or more layers made of one or more selected from the group consisting of Ni, Co, and Fe, is provided. Thereby, diffusion of Cu from the base material 2 into the silver-containing film 4 can be suppressed.
It is particularly preferable that the base layer 3 contains Ni in terms of plating workability and the like. Further, the base layer 3 may have multiple layers.

The average thickness of the base layer 3 (for example, the average thickness of the base layer 3 obtained from cross sections of two or more arbitrary locations of the terminal material) is preferably 0.1 μm or more, and more preferably 0.2 μm or more. This suppresses pinholes and effectively prevents copper diffusion. On the other hand, if the base layer 3 becomes too thick, the effect of suppressing Cu diffusion may become saturated. From the viewpoints of productivity, cost, and processability during terminal molding, the average thickness of the base layer 3 is preferably 3.0 μm or less, and more preferably 2.0 μm or less.

The silver plating layer 4a is a layer containing 50% by mass or more of silver. As the silver plating layer 4a, in addition to soft Ag plating, hard Ag plating, bright Ag plating, semi-bright Ag plating, etc. used for normal terminal surface treatment, corrosion resistance (sulfidation resistance, etc.) of the silver-containing film 4 can be improved. It is also possible to use Ag alloy plating containing Sn and/or Ni etc. for the purpose of improving micro-sliding wear resistance. However, since micro-sliding wear resistance can be imparted mainly by particles 4b made of non-conductive organic compounds, if there is no other purpose such as improving corrosion resistance, a pure Ag plating layer with excellent conductivity may be used as a carrier. For example, it is preferable that silver is contained in an amount of 90% by mass or more, more preferably 95% by mass or more, and even more preferably 99% by mass or more.

The average thickness of the silver plating layer 4a (for example, the average thickness of the silver plating layer 4a obtained from two or more arbitrary cross sections of the terminal material) is not particularly limited, and can be adjusted as appropriate depending on the application, but For example, the thickness may be 100 μm or less, or even 50 μm or less.

Regarding the particles 4b made of a non-conductive organic compound, "non-conductive" means not exhibiting conductivity; for example, the volume resistivity measured based on ASTM D257 is approximately 10 ³ [Ω·cm] or more. refers to something that indicates the value of

Regarding the particles 4b made of non-conductive organic compounds, "organic compounds" include carbon-containing compounds such as carbon monoxide, carbon dioxide, carbonates, hydrocyanic acid, cyanates, thiocyanates, B ₄ C and SiC. This refers to compounds excluding compounds with simple structures such as. For example, a silicone resin having a siloxane bond (-Si-O-Si-) as its main chain and an organic group in its side chain is included in the "organic compound" in this specification.

The non-conductive organic compound has a fluoro group (-F), a methyl group (-CH ₃ ), a carbonyl group (-C(=O)-), an amino group (-NR ¹ R ^{2 )} in the unit molecular structure. R ¹ and R ² are hydrogen or a hydrocarbon group, and R ¹ and R ² may be the same or different) and a hydroxy group (-OH). It is preferable to include. More preferably, the unit molecule structure contains a carbonyl group (-C(=O)-) and does not have a ring structure. Thereby, the resistance to slight sliding wear can be further improved.
Here, the "unit molecular structure" means one repeating unit in the case of a high molecule (polymer), and each molecule in the case of a non-polymer.

Regarding the particles 4b made of a non-conductive organic compound, the term "particle" means a relatively small substance with an equivalent circle diameter of 50 μm or less, and may have any shape. In one embodiment of the present invention, from the viewpoint of conductivity, the average particle diameter (average equivalent circle diameter) of the particles 4b may be 10 μm or less. Moreover, in one embodiment of the present invention, from the viewpoint of micro-sliding wear resistance, the average particle diameter of the particles 4b may be 0.1 μm or more.

FIG. 2 shows a schematic cross-sectional view of another example of a terminal material according to an embodiment of the present invention, in which the particles 4b are embedded in the silver plating layer 4a in the terminal material 11. Here, "embedded" means that, for each particle 4b, either all of the particles 4b are embedded in the silver plating layer 4a, or a portion of the particles 4b is embedded in the silver plating layer 4a, with the remaining portion exposed on the surface of the silver plating layer 4a.

FIG. 3 shows a schematic cross-sectional view of another example of the terminal material according to the embodiment of the present invention, and in the terminal material 21, the particles 4b are completely buried in the silver plating layer 4a. In the case of FIG. 3, the particles 4b may be large enough to be completely buried in the silver plating layer 4a, that is, the average particle size of the particles 4b may be less than the thickness of the silver plating layer 4a.

In the terminal material according to the embodiment of the present invention, "the particles are in contact" may mean, for example, that the particles 4b are in contact with (adhere to) the surface of the silver plating layer 4a as shown in FIG. It may be eutectoid (buried) in the silver plating layer 4a. In that case, each particle 4b may be completely buried in the silver plating layer 4a as shown in FIG. 3, or a part of each particle 4b may be exposed on the surface of the silver plating layer 4a as shown in FIG. Good too. Note that whether or not "the particles are in contact" can be determined, for example, by observing the cross section of the terminal material 1 (11, 21).

From the viewpoint of further increasing conductivity (further reducing contact resistance), particles 4b are eutectoid (buried) in silver plating layer 4a as shown in FIG. 2, or silver plating is used as shown in FIG. Preferably, it is completely buried in the layer 4a. On the other hand, from the viewpoint of further improving micro-sliding wear resistance, the particles 4b may be in contact with (adhering to) the surface of the silver plating layer 4a as shown in FIG. It is preferable that it is eutectoid (buried) in the plating layer 4a.

In the

terminal materials

1, 11, and 21 according to the embodiments of the present invention, the conductive particles may be in contact with the silver plating layer 4a depending on the case, but the fewer the conductive particles are, the more the contact will be damaged due to their falling off. This is preferable because short circuits can be suppressed. Therefore, it is preferable that 50% by volume or more of the particles 4b in contact with the

terminal materials

1, 11, and 21 according to the embodiment of the present invention are made of a non-conductive organic compound, and 60% by volume or more, 70% by volume or more. It is more preferably at least 80 vol%, or at least 90 vol%, and even more preferably the particles 4b are made entirely (100 vol%) of a non-conductive organic compound. Further, the

terminal materials

1, 11, and 21 according to the embodiments of the present invention may be in contact with inorganic particles depending on the case.

The

terminal materials

1, 11, and 21 according to the embodiments of the present invention may include other layers (for example, a strike plating layer, etc.) in order to achieve the object of the present disclosure.

As a method for manufacturing the terminal material 1 according to the embodiment of the present invention, for example, first, under general conditions, Ni, Co, and Fe, which are materials having a copper diffusion suppressing effect, are placed on a base material 2 such as a copper plate. A predetermined plating solution containing one or more selected from the group is energized to form the base layer 3. Thereafter, a silver (or silver alloy) plating solution is energized under general conditions to form a silver plating layer 4a. Then, a dispersion of particles 4b made of a non-conductive organic compound is applied to the surface. Thereby, terminal material 1 is obtained. Note that, depending on the case, strike silver plating treatment may be performed before silver plating treatment.

In the above manufacturing method, particles 4b made of a non-conductive organic compound are dispersed in a silver (or silver alloy) plating solution and electroplated with stirring. A terminal material eutectoid in the silver plating layer 4a (terminal material 11 in which part of the particles 4b are exposed on the surface of the silver plating layer 4a or terminal material 21 in which all the particles 4b are buried in the silver plating layer 4a) is obtained.

In the process of electroplating by dispersing particles 4b in a plating solution and eutectoiding particles 4b into silver plating layer 4a, the following reactions (A) and (B) proceed simultaneously.
(A) Reaction in which particles dispersed in liquid are electrostatically or physically adsorbed (contacted) on the surface of the substrate (B) Reaction in which silver plating layer 4a is deposited (grown) on the surface of the substrate (A) "Eutectoid" occurs when the particles 4b are incorporated into the silver plating layer 4a of (B). Under conditions where eutectoid plating progresses steadily, adsorption of new particles 4b occurs at the same time as the particles 4b adsorbed at the initial stage of the reaction are taken into the silver plating layer 4a. For this reason, even when the plating process is stopped, particles 4b are often exposed on the outermost surface, and in the normal eutectoid plating process, terminals with some of the particles 4b exposed on the surface of the silver plating layer 4a are Material 11 can be easily manufactured.
Here, since the amount of particles 4b eutectoided into the silver plating layer 4a is determined by the balance between the adsorption frequency of (A) and the plating film growth rate of (B), the plating conditions (and plating bath conditions) By changing the amount of eutectoid, it is possible to change the amount of eutectoid. For example, at the final stage of the plating process, by performing the process using a plating solution that does not contain the particles 4b dispersed in the plating solution, or by changing the stirring speed of the plating solution to reduce the adsorption frequency of (A), etc. By providing a layer that does not eutectoid particles 4b on the outermost surface side of the plating, it is possible to manufacture the terminal material 21 in which all the particles 4b are buried in the silver plating layer 4a.

The

terminal materials

1, 11, and 21 according to the embodiments of the present invention have sufficient electrical conductivity as well as sufficient fretting wear resistance. Specifically, the

terminal materials

1, 11, and 21 according to the embodiments of the present invention can reduce the initial contact resistance to 1.0 mΩ or less, and can also reduce the contact resistance to 1.0 mΩ or less even after 10,000 cycles of the fretting wear test described below. It is preferable that the

terminal materials

1, 11, and 21 according to the embodiments of the present invention can reduce the contact resistance to 1.0 mΩ or less even after 20,000 cycles of the fretting wear test described below.
<Fresh Wear Test>
A terminal material to be tested and a mating material having a hemispherical protrusion with a curvature radius R of 1.8 mm formed on the silver-containing film side surface of the terminal material by, for example, a hand press are prepared, and the surface of the mating material having the protrusion is slid back and forth against the silver-containing film side surface of the terminal material to be tested for a predetermined number of cycles with an applied normal load of 3 N, a sliding distance of 50 μm, and a sliding speed of 100 μm/sec. As a sliding tester, for example, a CRS-B1050CHO manufactured by Yamazaki Seiki Kenkyusho can be used.

The terminal according to the embodiment of the present invention includes

terminal materials

1, 11, and 21 according to the embodiment of the present invention. The terminal according to the embodiment of the present invention can be produced by molding the

terminal materials

1, 11 and 21 according to the embodiment of the present invention into a terminal shape, or by first molding a base material 2 into a terminal shape, and then forming the base material 2 into a terminal shape. The base layer 3 is one or more layers made of one or more selected from the group consisting of Ni, Co, and Fe, and the silver-containing film 4 (silver plating layer 4a and particles 4b made of a non-conductive organic compound). ). Terminals according to embodiments of the present invention can be used to directly connect equipment such as engines and motors to an ECU.

Hereinafter, embodiments of the present invention will be described in more detail with reference to Examples. The embodiments of the present invention are not limited by the following examples, and can be implemented with appropriate changes within the scope that can meet the spirit described above and below. It is included within the technical scope of the embodiment.

Using pure copper (copper content of 99% by mass or more) with a thickness of 0.3 mm as a base material, the surface of the base material was degreased by washing with acetone, and then using a matte Ni Watt bath and using a Ni plate as a counter electrode, 5A/d. Current was applied for ² minutes at a current density of 2 to form a 1 μm thick underlayer (Ni content of 99% by mass or more). Thereafter, using a commercially available strike Ag plating solution (Dyne Silver GPE-ST manufactured by Daiwa Kasei Co., Ltd.), electricity was applied for 1 minute at a current density of 5 A/dm ² to form a strike Ag plating layer (silver) with a thickness of approximately 0.1 μm. content of 99% by mass or more). After that, using a commercially available non-cyanide semi-bright Ag plating solution (Dyne Silver GPE-SB, manufactured by Daiwa Kasei Co., Ltd.), we coated the surface-active particles with various non-conductive organic compound particles with equivalent circle diameters of 50 μm or less shown in Table 1. A predetermined amount of agent (dispersant) is dispersed in the plating solution, and while stirring, electricity is applied for 5 minutes at a current density of 3 A/dm ² with a pure Ag plate as the counter electrode, resulting in semi-gloss Ag plating with a thickness of approximately 10 μm. No. 1, which includes a silver-containing film in which each particle is eutectoid (buried) in a layer (silver content of 99% by mass or more). Terminal materials Nos. 1 to 4 were obtained. In addition, No. As surfactants 1 to 3, Surflon S231 (manufactured by AGC Seimi Chemical) was used, and the amount added was 50 g/L. Also No. In No. 4, sodium naphthalene sulfonate was used as a surfactant and carboxymethyl cellulose (CMC) was used as a dispersant (stabilizer).

No. As a comparison of terminal materials No. 1 to No. 4, No. 1 containing no particles made of a non-conductive organic compound was used. Terminal materials Nos. 5 and 6 were prepared. No. 5 is No. 1 to 4, a semi-bright Ag plating layer (silver content of 99% by mass or more). No. 6 is No. Unlike in steps 1 to 4, a strike Ag plating layer (silver content of 99% by mass or more) with a thickness of about 0.1 μm is formed using a cyan bath as the strike Ag plating solution, and then a semi-bright Ag plating solution is used as a glossy one. By changing to an Ag plating solution (N-BRIGHT manufactured by Metallo Technologies), pure Ag plates were produced without dispersing particles and surfactants (dispersants) made of various non-conductive organic compounds in the bright Ag plating solution. As a counter electrode, electricity was applied for 15 minutes at a current density of 1.5 A/dm ² to form a glossy Ag plating layer (silver content of 99% by mass or more) with a thickness of about 10 μm.

No. 1~No. Initial contact resistance evaluation and micro-sliding wear resistance evaluation were performed on the terminal material No. 6.

<Initial contact resistance evaluation>
No. Using an electrical contact simulator (manufactured by Yamazaki Seiki Laboratory), the silver-containing film side surface of the terminal materials Nos. 1 to 6 was subjected to a four-terminal method under conditions of an open voltage of 20 mV, a current of 10 mA, and a load of 3 N. The measurement was carried out twice, and the average value was taken as the initial contact resistance value. When the contact resistance exceeded 1.0 mΩ, the conductivity was determined to be poor (×), and when the contact resistance was 1.0 mΩ or less, the conductivity was determined to be sufficient (◯).

<Slight sliding wear resistance evaluation>
No. Terminal materials Nos. 1 to 6 (size 10 cm x 10 cm) and a mating material (size 0.5 cm) in which hemispherical protrusions with a radius of curvature R = 1.8 mm were formed by hand pressing on the silver-containing film side surface of the terminal materials. No. 5 cm x 5 cm) was prepared, and the surface of the mating material having the protrusions was prepared. Vertical load: 3N, sliding distance: 50 μm, sliding speed: applied to the silver-containing film side surface of the terminal materials 1 to 6 using a CRS-B1050CHO manufactured by Yamazaki Seiki Laboratory as a sliding tester. One cycle was reciprocating sliding at 100 μm/sec, and sliding was performed for a predetermined number of cycles, and the contact resistance after each cycle was measured in the same manner as above. The results are shown in FIGS. 4 to 9. FIGS. 4 to 9 respectively show test No. These are the results of micro-sliding wear tests conducted on terminal materials Nos. 1 to 6 with N=2.
The number of cycles at which the contact resistance exceeds 1.0 mΩ, the shorter of which is less than 10,000 among N = 2, is considered defective (x), and those with a contact resistance of 10,000 or more and less than 20,000 are ○ (satisfactory), 20,000. The above items were rated as ◎ (good). In addition, wear marks were observed after 20,000 cycles, and the presence or absence of exposure of the base material (or base layer) was evaluated.

The above results are summarized in Table 2. In addition, in the "Short circuit prevention" column, if 50% by volume or more of the particles in contact with the silver plating layer are non-conductive particles, short circuits at the contact points due to falling particles can be sufficiently suppressed (○). , if less than 50% by volume of the particles in contact with the silver plating layer are non-conductive particles (i.e. more than 50% by volume of the particles in contact with the silver plating layer are conductive particles), It was rated as (×) that there is a risk of a short circuit in the contacts due to falling off. In the “Overall Judgment” column, if all of the “Short Circuit Prevention”, “Conductivity”, and “Slight Abrasion Resistance” columns are judged as “〇”, write “〇”, and then write “〇”. If there is a judgment of “◎” in the “Slight sliding abrasion resistance” column, write “◎”, and if there is one “×” judgment in the “Short circuit prevention”, “Conductivity” and “Slight sliding abrasion resistance” columns. If it is, it is marked as “×”.

From the results in Table 2, the following can be considered. No. of Table 2 All of the terminal materials Nos. 1 to 4 satisfy the requirements specified in the embodiment of the present invention, can sufficiently suppress short circuits of contacts due to falling off of conductive particles, and have sufficient conductivity and micro-sliding resistance. It had abrasive properties. Among them No. Silver-containing films 1 to 3 satisfied the preferable requirements that the non-conductive organic compound contains a carbonyl group (-C(=O)-) in the unit molecular structure and does not have a ring structure, The number of cycles at which the contact resistance exceeded 1.0 mΩ was 20,000 or more.

No. Terminal materials Nos. 5 and 6 had a contact resistance of more than 1.0 mΩ in less than 10,000 cycles of the micro-sliding abrasion test. This is No. In the terminal materials No. 5 and 6, the particles made of the non-conductive organic compound are not in contact with the silver plating layer, and the base material (or base layer) is easily exposed due to slight sliding wear. This is thought to be due to an increase in contact resistance due to oxidation. In addition, No. 6 is No. Although the silver plating layer was made harder by the action of the brightener than in No. 5, and the timing at which the contact resistance increased was slightly delayed, no significant improvement was observed.

This application claims priority to the Japanese patent application, Japanese Patent Application No. 2022-151505, whose filing date is September 22, 2022, as the basic application. Japanese Patent Application No. 2022-151505 is incorporated herein by reference.

1 Terminal material 2 Base material 3 Base layer 4 Silver-containing film 4a Silver plating layer 4b Particles made of non-conductive organic compound 11 Terminal material 21 Terminal material

Claims

A base material made of copper or a copper alloy, a base layer which is one or more layers made of one or more selected from the group consisting of Ni, Co and Fe, and a silver-containing film, in this order,
The silver-containing film includes a silver plating layer containing 50% by mass or more of silver, and particles made of a non-conductive organic compound with an equivalent circle diameter of 50 μm or less that are in contact with the silver plating layer,
A terminal material whose contact resistance on the silver-containing film side surface is 1 mΩ or less when subjected to the following micro-sliding abrasion test.
Micro-sliding wear test: Prepare the terminal material to be tested and a mating material in which a hemispherical protrusion with a radius of curvature R = 1.8 mm is formed on the surface of the terminal material on the silver-containing film side. The surface having the projections of the mating material is reciprocated by applying a vertical load of 3 N, sliding distance: 50 μm, and sliding speed: 100 μm/sec against the silver-containing film side surface of the terminal material to be tested. One cycle is sliding for 10,000 cycles.
The terminal material according to claim 1, wherein the silver plating layer contains 90% by mass or more of silver.
The terminal material according to claim 1, wherein the non-conductive organic compound contains a carbonyl group (-C(=O)-) in a unit molecule structure and does not have a ring structure.
The terminal material according to claim 2, wherein the non-conductive organic compound contains a carbonyl group (-C(=O)-) in a unit molecule structure and does not have a ring structure.
A terminal using the terminal material described in any one of claims 1 to 4.