WO2023182259A1 - Terminal material and electrical connection terminal - Google Patents

Terminal material and electrical connection terminal Download PDF

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Publication number
WO2023182259A1
WO2023182259A1 PCT/JP2023/010836 JP2023010836W WO2023182259A1 WO 2023182259 A1 WO2023182259 A1 WO 2023182259A1 JP 2023010836 W JP2023010836 W JP 2023010836W WO 2023182259 A1 WO2023182259 A1 WO 2023182259A1
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WIPO (PCT)
Prior art keywords
alloy
coating layer
terminal
layer
base material
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PCT/JP2023/010836
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French (fr)
Japanese (ja)
Inventor
倫丈 竃本
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株式会社オートネットワーク技術研究所
住友電装株式会社
住友電気工業株式会社
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Publication of WO2023182259A1 publication Critical patent/WO2023182259A1/en

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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
    • C25D5/10—Electroplating with more than one layer of the same or of different metals
    • C25D5/12—Electroplating with more than one layer of the same or of different metals at least one layer being of nickel or chromium
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
    • C25D5/48—After-treatment of electroplated surfaces
    • C25D5/50—After-treatment of electroplated surfaces by heat-treatment
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D7/00—Electroplating characterised by the article coated
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R13/00—Details of coupling devices of the kinds covered by groups H01R12/70 or H01R24/00 - H01R33/00
    • H01R13/02—Contact members
    • H01R13/03—Contact members characterised by the material, e.g. plating, or coating materials

Definitions

  • the present disclosure relates to terminal materials and electrical connection terminals.
  • a material in which a coating layer made of another metal is provided on the surface of a base material made of metal such as copper or copper alloy is often used.
  • the covering layer can impart desired properties to the electrical connection terminal.
  • a coating layer containing a Cu--Sn alloy is known as a coating layer that can reduce friction on the surface of a terminal material and reduce the insertion force (combinant force) required to connect an electrical connection terminal.
  • an alloy part 41 made of a Cu-Sn alloy and having irregularities is formed, as in the terminal material 9 shown in FIG.
  • a structure in which the portion 42 covers the surface of the alloy portion 41 is formed. It is said that because the alloy part 41 made of a hard Cu-Sn alloy is present below the Sn part 42, the effect of lowering friction can be obtained at the same time as the effect of lowering contact resistance due to the contribution of the Sn part 42. .
  • Patent Document 1 discloses that at least the surface of the contact part with the mating material of the copper alloy base material is , discloses a terminal including a layer obtained by reflow processing a layer formed by sequentially laminating a nickel plating layer, a copper plating layer, and a tin plating layer with a thickness of 1.1 ⁇ m or less. A copper-tin alloy layer is formed by the reflow process. Patent Document 1 states that by making the tin plating layer thinner, the mechanical resistance caused by plastic deformation during terminal insertion can be reduced.
  • Patent Document 1 attempts to reduce the insertion force of the terminal by thinning the Sn plating layer, which is the raw material for alloy formation, but does not mention the Cu-Sn alloy and the distribution of Sn in the coating layer. Not yet. By considering the distribution of Cu-Sn alloy and Sn in the coating layer, it is possible that friction can be effectively reduced.
  • the terminal material of the present disclosure includes a base material and a coating layer that covers the surface of the base material, and the coating layer includes an alloy portion made of a Cu-Sn alloy and a Sn , both the alloy part and the Sn part are exposed on the surface of the coating layer, and the alloy exposure rate indicating the area ratio occupied by the alloy part on the surface of the coating layer is 30%. That's all.
  • the electrical connection terminal of the present disclosure is configured to include the terminal material, and the coating layer is formed on the surface of the base material at least in the contact portion that contacts the other conductive member.
  • the terminal material and electrical connection terminal according to the present disclosure are terminal materials that can effectively reduce surface friction from the viewpoint of the distribution of Cu-Sn alloy and Sn in the coating layer containing Cu-Sn alloy and Sn. , and such electrical connection terminals.
  • FIG. 1 is a cross-sectional view schematically showing the configuration of a terminal material according to an embodiment of the present disclosure.
  • FIG. 2 is a cross-sectional view showing the structure of material layers for forming the terminal material.
  • FIG. 3 is a cross-sectional view schematically showing the structure of an electrical connection terminal according to an embodiment of the present disclosure.
  • FIG. 4 shows a table of scanning electron microscope images obtained by observing the surface of the coating layer, the binarized image obtained from the images, and the alloy exposure rate.
  • FIG. 5 is a diagram in which the alloy exposure rate and the terminal insertion force are plotted against the thickness of the Sn portion.
  • FIG. 6 is a cross-sectional view schematically showing the structure of a terminal material in which the Sn portion is formed thick.
  • the terminal material of the present disclosure includes a base material and a coating layer that covers the surface of the base material, and the coating layer includes an alloy portion made of a Cu-Sn alloy and a Sn , both the alloy part and the Sn part are exposed on the surface of the coating layer, and the alloy exposure rate indicating the area ratio occupied by the alloy part on the surface of the coating layer is 30%. That's all.
  • the Cu--Sn alloy comes into direct contact with the other party's conductive member, such as the other party's terminal. Furthermore, since the amount of Sn portions present on the surface of the coating layer is reduced, wear due to digging up or adhesion of the Sn portions becomes less likely to occur. As a result, the friction on the surface of the coating layer is kept low. In particular, when the alloy exposure rate on the surface of the coating layer is 30% or more, the friction reduction effect of the Cu--Sn alloy can be sufficiently obtained.
  • the alloy exposure rate is preferably 50% or less.
  • a coating layer in which Sn is exposed at a certain exposure rate along with the Cu--Sn alloy can be easily manufactured by a method of laminating and heating a Cu layer and a Sn layer. Further, by sufficiently exposing Sn to the surface of the coating layer, the friction reduction effect due to the contribution of the Cu--Sn alloy and the effect due to the contribution of Sn, such as reduction in contact resistance, are both achieved.
  • the average thickness of the Sn portion is preferably 0.10 ⁇ m or more and 0.35 ⁇ m or less. Further, the average thickness of the alloy portion is preferably 0.25 ⁇ m or more and 0.48 ⁇ m or less. Then, by a method of laminating and heating a Cu layer and a Sn layer, a coating layer having a high alloy exposure rate and an excellent friction reduction effect can be manufactured.
  • the base material is made of Cu or a Cu alloy, and further includes a diffusion suppressing layer made of Ni or a Ni alloy between the base material and the coating layer.
  • the diffusion suppressing layer made of Ni and Ni alloy effectively suppresses atoms such as Cu constituting the base material from diffusing into the coating layer. Thereby, it is possible to reduce the influence of atomic diffusion from the base material, exhibit a predetermined alloy exposure rate, and stably obtain a coating layer with reduced friction.
  • the electrical connection terminal of the present disclosure is configured to include the terminal material, and the coating layer is formed on the surface of the base material at least in the contact portion that contacts the other conductive member.
  • both the alloy part and the Sn part are exposed on the surface of the contact part and have a predetermined alloy exposure ratio, so that the contact part can maintain a low surface friction coefficient as described above. It becomes what is given.
  • the electrical connection terminal is preferably configured as a male terminal for a printed circuit board.
  • Male terminals for printed circuit boards are often constructed as post-plated products in which a base material is formed into the terminal shape and then a metal coating layer is formed. , the thickness of the coating layer is unevenly distributed, and a thick metal coating layer is likely to be formed at sharp points such as the tips of male terminals. As a result, friction may increase at the tip.
  • an alloy exposure rate of 30% or more is ensured, so even if there are areas where the coating layer is locally thick, surface friction is effectively reduced, including at those areas. low insertion force can be achieved.
  • the term "elementary metal” includes cases where it contains unavoidable impurities.
  • alloy includes both a solid solution and an intermetallic compound.
  • an alloy containing a certain metal as a main component refers to an alloy in which the metal element is contained in the composition in an amount of 50 atomic % or more.
  • Terminal materials according to embodiments of the present disclosure will be described below.
  • a cross section of a terminal material 1 according to an embodiment of the present disclosure is schematically shown in FIG.
  • the terminal material 1 includes a base material 2 and a coating layer 4 that covers the surface of the base material 2. Although optional, it is preferable to provide a diffusion suppressing layer 3 between the base material 2 and the coating layer 4.
  • the coating layer 4 is preferably exposed on the outermost surface of the terminal material 1, but a thin film (not shown) such as an organic layer may be added to the surface of the coating layer 4 unless it significantly affects the characteristics of the coating layer 4. may be provided.
  • the material constituting the base material 2 is not particularly limited.
  • the base material 2 Cu or Cu alloy, Al or Al alloy, Fe or Fe alloy, etc., which are often used as constituent materials of electrical connection members, can be suitably used.
  • Cu or Cu alloy which is a metal with excellent conductivity and mechanical properties, can be suitably used.
  • the diffusion suppression layer 3 is a layer that suppresses atoms such as Cu that constitute the base material 2 from diffusing into the coating layer 4.
  • constituent atoms of the base material diffuse to the surface of the coating layer 4 and undergo oxidation, the contact resistance of the surface of the coating layer 4 increases. Further, due to the influence of the diffused constituent atoms of the base material, there is a possibility that the desired composition and material distribution cannot be obtained in the coating layer 4. Therefore, by providing the diffusion suppressing layer 3 between the base material 2 and the coating layer 4, it is possible to suppress those phenomena that may occur when constituent atoms of the base material diffuse into the coating layer 4.
  • the type of diffusion suppressing layer 3 is not limited as long as it can suppress the diffusion of constituent atoms of the base material, but Ni or Ni alloy is preferably used as a metal that exhibits a high diffusion suppressing effect. It can be applied to Although the thickness of the diffusion suppressing layer 3 is not particularly limited, it is preferably 0.5 ⁇ m or more from the viewpoint of obtaining a sufficient diffusion suppressing effect. On the other hand, from the viewpoint of workability, etc., the thickness is preferably 2 ⁇ m or less. At the interface between the diffusion suppressing layer 3, the base material 2, and the coating layer 4, a region where the metal forming the diffusion suppressing layer 3 and the metal forming the base material 2 and the coating layer 4, respectively, formed an alloy is formed. may have.
  • the covering layer 4 is configured as a metal layer containing Sn and Cu.
  • the coating layer 4 does not have a uniform composition and includes both an alloy part 41 made of a Cu--Sn alloy and an Sn part 42 made of Sn. It is preferable that the coating layer 4 is composed only of Sn and Cu, excluding unavoidable impurities and atoms that unavoidably diffuse from the base material 2 and the diffusion suppressing layer 3. It is preferable that the alloy part 41 and the Sn part 42 be composed of only a Cu-Sn alloy and Sn, respectively, excluding unavoidable impurities, but a small amount of impurities or additive elements other than the Cu-Sn alloy and Sn may be added. (for example, 10% by mass or less).
  • the composition of the Cu--Sn alloy constituting the alloy portion 41 is not particularly limited, it is preferably composed of an intermetallic compound of Cu 6 Sn 5 as a main component. The details of the structure of the coating layer 4 will be explained below.
  • the coating layer 4 has an alloy part 41 made of a Cu-Sn alloy and an Sn part 42 made of Sn, and both the alloy part 41 and the Sn part 42 is exposed on the surface of the coating layer 4.
  • the alloy portion 41 is configured as a layer having an uneven structure projecting like a mountain.
  • the Sn portion 42 is formed by covering the alloy portion 41 so as to fill the unevenness of the uneven structure.
  • the coating layer 4, which includes the alloy part 41 made of a Cu-Sn alloy having an uneven structure and the Sn part 42 covering the surface thereof, is formed by combining the Cu layer 5 and the Sn layer 6 as described later. It can be easily manufactured by sequentially laminating the layers and heating them.
  • both the alloy part 41 and the Sn part 42 are exposed on the outermost surface of the coating layer 4. That is, near the top of the convex portion of the uneven structure of the alloy portion 41, there is an exposed alloy portion 41a where the Cu—Sn alloy is exposed and is not covered with the Sn portion 42. Then, on the surface of the coating layer 4, the area ratio occupied by the alloy part 41, that is, the alloy exposure ratio expressed as the ratio of the area occupied by the exposed alloy part 41a to the entire surface area is 30% or more. There is.
  • the Sn portion 42 exhibits low contact resistance and provides good electrical connection characteristics between the surface of the terminal material 1 and the other conductive member.
  • the alloy portion 41 plays a role in keeping the friction low (reducing the coefficient of friction) in the coating layer 4 because the Cu--Sn alloy has characteristics such as high hardness.
  • the presence of the alloy portion 41 in the lower layer of the Sn portion 42 provides a friction reduction effect on the surface of the Sn portion 42 . Further, since the alloy portion 41 is exposed on the outermost surface and comes into direct contact with the other conductive member, an even higher effect in reducing friction can be obtained.
  • both the Sn portion 42 and the alloy portion 41 made of Cu-Sn are exposed on the surface of the coating layer 4, so that contact resistance can be reduced, etc. It is possible to enjoy both the effects of the alloy portion 41 and the effects of the alloy portion 41, such as reduction of friction.
  • the Sn portion 42 is formed thickly as shown in FIG. By occupying a large volume, when sliding is performed between the Sn portions 42 and the other conductive member, the Sn portions 42 cause digging and adhesion, thereby increasing the coefficient of friction.
  • the alloy exposure rate of the alloy part 41 is 30% or more. This results in a particularly excellent friction reduction effect.
  • the alloy part 41 occupies 30% or more of the surface of the coating layer 4, comes into contact with the other conductive member, and is directly involved in the friction phenomenon during sliding, so that the friction reduction effect of the alloy part 41 is highly exhibited. It is from.
  • the fact that the exposure rate of the alloy part 41 is high means that the thickness of the Sn part 42 covering the alloy part 41 is kept small, and the amount of Sn part 42 present in the coating layer 4 is reduced. It means that.
  • the terminal material 1 according to the present embodiment has an excellent effect of reducing friction on the surface of the coating layer 4. This reduction in friction is obtained as a result of the distribution of the alloy portions 41 and Sn portions 42 in the coating layer 4.
  • the alloy exposure rate is more preferably 35% or more, more preferably 40% or more, or 45% or more.
  • the upper limit of the alloy exposure rate is not particularly determined, but it is preferably kept at about 50% or less, and even 48% or less. An alloy exposure rate of 30% or more and below these upper limits can be easily achieved in the structure of the coating layer 4 in which the Sn part 42 covers the surface of the alloy part 41 having an uneven structure. It can be easily obtained by a method of laminating layers 6 and heating them. In addition, if the alloy exposure rate is below the above upper limit, the exposure rate of the Sn portion 42 will be ensured sufficiently large, so that in addition to the friction reduction effect of the alloy portion 41, the Sn portion The effects brought about by 42 can also be fully obtained.
  • the details of the thickness and distribution of the Sn portion 42 and the alloy portion 41 are not particularly limited as long as the above alloy exposure rate is given. However, since it is easy to provide the coating layer 4 having an alloy exposure rate of 30% or more and preferably 50% or less, and it is easy to form the coating layer 4 by laminating and heating the Cu layer 5 and the Sn layer 6, the coating It is preferable that layer 4 has the following configuration.
  • the thickness of the Sn portion 42 is preferably smaller than the thickness (average value; the same applies below) of the alloy portion 41.
  • the thicknesses of the Sn portion 42 and the alloy portion 41 are not particularly limited.
  • the thickness (average value) of the Sn portion 42 is preferably 0.35 ⁇ m or less, more preferably 0.25 ⁇ m or less, or 0.20 ⁇ m or less. This makes it easy to ensure a high alloy exposure rate, and it is also possible to effectively suppress an increase in friction due to digging up or adhesion of the Sn portion 42.
  • the thickness (average value) of the Sn portion 42 is preferably 0.10 ⁇ m or more, more preferably 0.12 ⁇ m or more.
  • the thickness (average value) of the alloy portion 41 should be 0.25 ⁇ m or more, further 0.30 ⁇ m or more, or 0.35 ⁇ m or more, from the viewpoint of ensuring a sufficient alloy exposure rate and making it easier to obtain the effect of reducing friction. It is preferable that there be.
  • the thickness of the alloy portion 41 is preferably 0.48 ⁇ m or less, and more preferably 0.45 ⁇ m or less.
  • the specific distribution shape of the alloy part 41 and the Sn part 42 exposed on the surface of the coating layer 4 is not particularly limited, but from the viewpoint of effectively utilizing the characteristics of both the alloy part 41 and the Sn part 42. It is only necessary that the alloy portion 41 and the Sn portion 42 are distributed so that they both occupy a certain amount of area and coexist at a location that contacts the other conductive member, such as a contact portion of a terminal.
  • the method of forming the coating layer 4 is not particularly limited, but a method of alloying Cu and Sn can be suitably used. That is, as shown in FIG. 2, a raw material 1' is prepared in which a Cu layer 5 and a Sn layer 6 are laminated in this order on the surface of a base material 2 on which a diffusion suppressing layer 3 is appropriately formed. The Cu layer 5 and the Sn layer 6 are preferably formed by electrolytic plating. Next, this raw material 1' is heated at a temperature equal to or higher than the melting point of Sn (reflow treatment). By heating, alloying of Cu and Sn occurs, and an alloy portion 41 made of a Cu--Sn alloy is formed.
  • the Sn that was not spent on alloying becomes the Sn portion 42.
  • the alloy portion 41 is formed as a layer having an uneven structure without any special operation, and the Sn layer is formed to fill the unevenness. 42 can form a coating layer 4 that covers the alloy part 41.
  • the alloy exposure rate in the coating layer 4 can be controlled, for example, by the thicknesses of the Cu layer 5 and the Sn layer 6 in the raw material 1'. From the viewpoint of sufficiently increasing the alloy exposure rate, the thickness of the Sn layer 6 should be kept at 6.0 times or less, further 5.0 times or less, and 4.0 times or less than the Cu layer 5. It is preferable to leave it there. Further, the thickness of the Sn layer 6 is preferably set to 0.60 ⁇ m or less, 0.50 ⁇ m or less, or 0.40 ⁇ m or less.
  • the thickness of the Sn layer 6 is set to 1 It is preferable to set it to .0 times or more, further 2.0 times or more, or 3.0 times or more. Further, the thickness of the Sn layer 6 is preferably set to 0.10 ⁇ m or more, 0.20 ⁇ m or more, or 0.30 ⁇ m or more.
  • the thickness of the Cu layer 5 is preferably 0.05 ⁇ m or more, or 0.10 ⁇ m or more, and preferably 0.20 ⁇ m or less.
  • the ratio of the thickness of the Sn layer 6 and the Cu layer 5 in the raw material 1' is the atomic ratio of Sn atoms and Cu atoms contained in the entire coating layer 4 in the coating layer 4 after alloy formation.
  • the value converted to the volume ratio of Cu can be confirmed from the configuration of the terminal material 1.
  • An electrical connection terminal is configured to include the terminal material 1 according to the embodiment of the present disclosure described above.
  • the coating layer 4 is formed at least on a contact portion such as a mating terminal that comes into contact with a mating conductive member.
  • the covering layer 4 (and the diffusion suppressing layer 3) may be formed on the entire surface of the electrical connection terminal or only on a part of the surface as long as it is formed on at least the contact portion.
  • FIG. 3 illustrates the structure of the PCB male terminal 10.
  • the PCB male terminal 10 is a long electrical connection terminal, and has a board connection part 11 at one end that is inserted into a through hole of a printed circuit board and connected, and the other end is inserted into a mating connection terminal. It has a terminal connection part 12 in the shape of a fitting type male terminal that is connected by a connector or the like.
  • a coating layer 4 is provided on the surface of the base material 2 at a location that includes at least the board connection portion 11 and the terminal connection portion 12, which serve as contact portions.
  • the coating layer 4 is formed over the entire surface.
  • both the alloy part 41 and the Sn part 42 are exposed on the surface of the coating layer 4, and by having an alloy exposure rate of 30% or more, friction is reduced. It has an excellent friction reduction effect, and electrical connection terminals made of the terminal material 1 according to the embodiment of the present disclosure, including the male terminal 10 for PCB, can enjoy the friction reduction effect at the contact portion. . That is, for example, insertion force (or fitting force; the same in this specification) is the force required when inserting and fitting the terminal connecting part 11 with a mating conductive member such as a female terminal with sliding movement. can be kept small.
  • a plurality of male PCB terminals 10 are often inserted and mated all at once in the state of a connector fixed to a connector housing, and reducing the insertion force of each terminal 10 has a large insertion force reduction effect for the connector as a whole. Leads to.
  • male terminals for PCBs are often formed by forming a base material into a predetermined terminal shape by punching or the like, and then forming a metal coating layer on the surface of the base material by plating (post-plating).
  • the thickness of the metal coating layer at sharp points such as the tips of the board connection part 11 and the terminal connection part 12 is affected by the primary current distribution during plating.
  • a non-uniform distribution in which the thickness is larger than other parts is likely to occur in the metal coating layer. If a metal coating layer such as a Sn layer that is prone to adhesion or digging is formed thickly at the contact portion, the terminal insertion force will increase.
  • the alloy portion 41 is exposed together with the Sn portion 42 on the surface of the coating layer 4, and the alloy exposure rate is 30% or more.
  • the alloy exposure rate is 30% or more.
  • a Ni diffusion suppressing layer with a thickness of 1 ⁇ m was formed on the surface of a flat copper alloy base material, and then a Cu layer and a Sn layer were formed in this order to obtain a raw material.
  • Each metal layer was formed by electrolytic plating.
  • the thickness of the Cu layer 5 was 0.1 ⁇ m, and the thickness of the Sn layer was as shown in Table 1 below.
  • this raw material was heated and subjected to a reflow treatment to form a coating layer including an alloy part and a Sn part by alloying Cu and Sn.
  • a copper alloy base material was punched into the shape of the male terminal for PCB shown in Fig. 3, and the surface was coated with a Ni layer, a Cu layer, and a Sn layer in the same manner as above.
  • a coating layer was formed on the terminal surface by layer formation and reflow treatment.
  • a 0.64 mm square terminal was used as the terminal.
  • the produced terminals were set in a connector housing to produce a 40-pole test model connector imitating a multi-pole connector for PCB.
  • FIG. 4 shows SEM images of the surfaces of a plurality of samples in which the thickness of the Sn layer of the raw material was varied, together with the binarized image and the value of the alloy exposure rate.
  • the scale bar in the SEM image indicates 50 ⁇ m.
  • the region observed darkly corresponds to the alloy part made of a Cu-Sn alloy, and the region observed brightly corresponds to the Sn part. From the SEM images, it is confirmed that both the alloy part and the Sn part are mixed and exposed on the surface of each sample.
  • the alloy exposure rate varies depending on the sample, and the alloy exposure rate tends to be high in regions where the Sn layer of the raw material has a relatively small thickness.
  • Table 1 summarizes the thickness of the Sn layer of the raw material, the alloy exposure rate, the thickness of each part, and the measured values of the connector fitting force for each sample.
  • the alloy exposure rate values shown in Table 1 and FIG. 5, which will be described later, are the average of the same measurement results as in FIG. 4 obtained at a plurality of observation points.
  • the values of the alloy exposure rate and the connector fitting force are plotted against the average thickness of the Sn portion in the coating layer for the data shown in Table 1.
  • the alloy exposure rate is indicated by a diamond, and its value is shown on the left axis.
  • the connector fitting force is indicated by a circle, and its value is shown on the right axis.
  • Terminal material 1' Raw material 10 Male terminal for PCB 11 Board connection part 12 Terminal connection part 2 Base material 3 Diffusion suppression layer 4 Covering layer 41 Alloy part 41a Alloy exposed part 42 Sn part 5 Cu layer 6 Sn layer 9 Sn part Thick terminal material

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  • Chemical Kinetics & Catalysis (AREA)
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Abstract

Provided are: a terminal material configured to effectively reduce the surface friction from the perspective of a Cu-Sn alloy and Sn distributions within a coating layer containing the Cu-Sn alloy and Sn; and an electrical connection terminal comprising such terminal material.　A terminal material 1 comprises a substrate 2 and a coating layer 4 that covers a surface of the substrate 2. The coating layer 4 has an alloy portion 41 composed of a Cu-Sn alloy, and a Sn portion 42 composed of Sn. On a surface of the coating layer 4, both the alloy portion 41 and the Sn portion 42 are exposed. On the surface of the coating layer 4, the alloy exposure rate, which is the area percentage that the alloy portion 41 accounts for, is 30% or more. The electrical connection terminal is configured to include the terminal material 1. The coating layer 4 is formed on the surface of the substrate 2, at least at a contact section where the terminal comes into contact with a mating electroconductive member.

Description

端子材料および電気接続端子Terminal materials and electrical connection terminals
　本開示は、端子材料および電気接続端子に関する。 The present disclosure relates to terminal materials and electrical connection terminals.
　電気接続端子を構成する端子材料としては、銅または銅合金等の金属よりなる基材の表面に、他種の金属よりなる被覆層を設けた材料が用いられることが多い。被覆層によって、電気接続端子に所望の特性を付与することができる。端子材料の表面における摩擦を低減し、電気接続端子の接続に要する挿入力（篏合力）を低減することができる被覆層として、Ｃｕ－Ｓｎ合金を含んだものが知られている。Ｃｕ層とＳｎ層を積層し、加熱により合金化を起こすと、図６に示す端子材料９のように、Ｃｕ－Ｓｎ合金よりなり凹凸を有する合金部４１が形成され、余剰のＳｎよりなるＳｎ部４２がその合金部４１の表面を覆った構造が形成される。硬質なＣｕ－Ｓｎ合金よりなる合金部４１がＳｎ部４２の下層に存在することで、低摩擦化の効果が、Ｓｎ部４２の寄与による低接触抵抗化の効果と同時に得られるとされている。 As the terminal material constituting the electrical connection terminal, a material in which a coating layer made of another metal is provided on the surface of a base material made of metal such as copper or copper alloy is often used. The covering layer can impart desired properties to the electrical connection terminal. A coating layer containing a Cu--Sn alloy is known as a coating layer that can reduce friction on the surface of a terminal material and reduce the insertion force (combinant force) required to connect an electrical connection terminal. When a Cu layer and a Sn layer are laminated and alloyed by heating, an alloy part 41 made of a Cu-Sn alloy and having irregularities is formed, as in the terminal material 9 shown in FIG. A structure in which the portion 42 covers the surface of the alloy portion 41 is formed. It is said that because the alloy part 41 made of a hard Cu-Sn alloy is present below the Sn part 42, the effect of lowering friction can be obtained at the same time as the effect of lowering contact resistance due to the contribution of the Sn part 42. .
　この種のＣｕ－Ｓｎ合金よりなる合金部とＳｎ部を含んだ被覆層を有する電気接続端子の具体例として、特許文献１では、銅合金製母材の少なくとも相手材との接触部の表面に、順次、ニッケルめっき層、銅めっき層及び１．１μｍ以下の厚さの錫めっき層を積層してなる層をリフロー処理して得られる層を含む端子が開示されている。リフロー処理により、銅錫合金層が形成される。特許文献１では、錫めっき層を薄層化することにより、端子挿入時における塑性変形に伴う機械的抵抗力を低減できるとしている。 As a specific example of an electrical connection terminal having a coating layer containing an alloy part made of this type of Cu-Sn alloy and a Sn part, Patent Document 1 discloses that at least the surface of the contact part with the mating material of the copper alloy base material is , discloses a terminal including a layer obtained by reflow processing a layer formed by sequentially laminating a nickel plating layer, a copper plating layer, and a tin plating layer with a thickness of 1.1 μm or less. A copper-tin alloy layer is formed by the reflow process. Patent Document 1 states that by making the tin plating layer thinner, the mechanical resistance caused by plastic deformation during terminal insertion can be reduced.
特開２００３－１４７５７９号公報Japanese Patent Application Publication No. 2003-147579
　上記のように、端子材料において、Ｃｕ－Ｓｎ合金よりなる合金部とＳｎ部を含む被覆層を基材の表面に形成することで、低摩擦化、および端子の低挿入力化を図ることが考えられる。しかし、被覆層の表面の摩擦挙動において、Ｃｕ－Ｓｎ合金とＳｎは、全く異なる寄与を示すはずである。すると、被覆層において、Ｃｕ－Ｓｎ合金とＳｎがどのように分布しているかが、摩擦の制御において重要となる。特許文献１では、合金形成の原料となるＳｎめっき層を薄層化することにより、端子の低挿入力化を図っているが、被覆層におけるＣｕ－Ｓｎ合金およびＳｎの分布については、言及されていない。被覆層におけるＣｕ－Ｓｎ合金とＳｎの分布を検討することで、摩擦の低減を効果的に達成できる可能性がある。 As mentioned above, in the terminal material, by forming a coating layer containing an alloy part made of a Cu-Sn alloy and a Sn part on the surface of the base material, it is possible to reduce friction and reduce the insertion force of the terminal. Conceivable. However, in the frictional behavior of the surface of the coating layer, the Cu-Sn alloy and Sn should show completely different contributions. Then, how the Cu--Sn alloy and Sn are distributed in the coating layer becomes important in controlling friction. Patent Document 1 attempts to reduce the insertion force of the terminal by thinning the Sn plating layer, which is the raw material for alloy formation, but does not mention the Cu-Sn alloy and the distribution of Sn in the coating layer. Not yet. By considering the distribution of Cu-Sn alloy and Sn in the coating layer, it is possible that friction can be effectively reduced.
　そこで、Ｃｕ－Ｓｎ合金とＳｎを含む被覆層における、Ｃｕ－Ｓｎ合金とＳｎの分布の観点から、表面の摩擦を効果的に低減することができる端子材料、およびそのような電気接続端子を提供することを課題とする。 Therefore, we provide a terminal material that can effectively reduce surface friction from the viewpoint of the distribution of Cu-Sn alloy and Sn in a coating layer containing Cu-Sn alloy and Sn, and such an electrical connection terminal. The task is to do so.
　本開示の端子材料は、基材と、前記基材の表面を被覆する被覆層と、を有し、前記被覆層は、Ｃｕ－Ｓｎ合金より構成される合金部と、Ｓｎより構成されるＳｎ部と、を有し、前記被覆層の表面には、前記合金部と前記Ｓｎ部の両方が露出され、前記被覆層の表面において前記合金部が占める面積率を示す合金露出率が、３０％以上である。 The terminal material of the present disclosure includes a base material and a coating layer that covers the surface of the base material, and the coating layer includes an alloy portion made of a Cu-Sn alloy and a Sn , both the alloy part and the Sn part are exposed on the surface of the coating layer, and the alloy exposure rate indicating the area ratio occupied by the alloy part on the surface of the coating layer is 30%. That's all.
　本開示の電気接続端子は、前記端子材料を含んで構成され、少なくとも、相手方導電部材と接触する接点部において、前記基材の表面に、前記被覆層が形成されている。 The electrical connection terminal of the present disclosure is configured to include the terminal material, and the coating layer is formed on the surface of the base material at least in the contact portion that contacts the other conductive member.
　本開示にかかる端子材料および電気接続端子は、Ｃｕ－Ｓｎ合金とＳｎを含む被覆層における、Ｃｕ－Ｓｎ合金とＳｎの分布の観点から、表面の摩擦を効果的に低減することができる端子材料、およびそのような電気接続端子となる。 The terminal material and electrical connection terminal according to the present disclosure are terminal materials that can effectively reduce surface friction from the viewpoint of the distribution of Cu-Sn alloy and Sn in the coating layer containing Cu-Sn alloy and Sn. , and such electrical connection terminals.
図１は、本開示の一実施形態にかかる端子材料の構成を模式的に示す断面図である。FIG. 1 is a cross-sectional view schematically showing the configuration of a terminal material according to an embodiment of the present disclosure. 図２は、上記端子材料を形成するための材料層の構成を示す断面図である。FIG. 2 is a cross-sectional view showing the structure of material layers for forming the terminal material. 図３は、本開示の一実施形態にかかる電気接続端子の構造を模式的に示す断面図である。FIG. 3 is a cross-sectional view schematically showing the structure of an electrical connection terminal according to an embodiment of the present disclosure. 図４は、被覆層の表面を観察した走査電子顕微鏡像と、そこから得られる２値化像および合金露出率を表にまとめたものである。FIG. 4 shows a table of scanning electron microscope images obtained by observing the surface of the coating layer, the binarized image obtained from the images, and the alloy exposure rate. 図５は、Ｓｎ部の厚さに対して、合金露出率および端子挿入力をプロットした図である。FIG. 5 is a diagram in which the alloy exposure rate and the terminal insertion force are plotted against the thickness of the Sn portion. 図６は、Ｓｎ部を厚く形成した端子材料の構成を模式的に示す断面図である。FIG. 6 is a cross-sectional view schematically showing the structure of a terminal material in which the Sn portion is formed thick.
［本開示の実施形態の説明］
　最初に本開示の実施形態を列記して説明する。
　本開示の端子材料は、基材と、前記基材の表面を被覆する被覆層と、を有し、前記被覆層は、Ｃｕ－Ｓｎ合金より構成される合金部と、Ｓｎより構成されるＳｎ部と、を有し、前記被覆層の表面には、前記合金部と前記Ｓｎ部の両方が露出され、前記被覆層の表面において前記合金部が占める面積率を示す合金露出率が、３０％以上である。 [Description of embodiments of the present disclosure]
First, embodiments of the present disclosure will be listed and described.
The terminal material of the present disclosure includes a base material and a coating layer that covers the surface of the base material, and the coating layer includes an alloy portion made of a Cu-Sn alloy and a Sn , both the alloy part and the Sn part are exposed on the surface of the coating layer, and the alloy exposure rate indicating the area ratio occupied by the alloy part on the surface of the coating layer is 30%. That's all.
　上記端子材料においては、被覆層の表面に、Ｓｎだけでなく、Ｃｕ－Ｓｎ合金が露出している。そのため、被覆層の表面において、Ｃｕ－Ｓｎ合金が直接、相手方の端子等、相手方導電部材と接触することになる。また、被覆層の表面におけるＳｎ部の存在量が少なくなることにより、Ｓｎ部の掘り起こしや凝着による摩耗が起こりにくくなる。それらの結果として、被覆層の表面の摩擦が低く抑えられる。特に、被覆層の表面における合金露出率が３０％以上であることで、Ｃｕ－Ｓｎ合金による摩擦の低減効果が、十分に得られる。 In the above terminal material, not only Sn but also the Cu-Sn alloy is exposed on the surface of the coating layer. Therefore, on the surface of the coating layer, the Cu--Sn alloy comes into direct contact with the other party's conductive member, such as the other party's terminal. Furthermore, since the amount of Sn portions present on the surface of the coating layer is reduced, wear due to digging up or adhesion of the Sn portions becomes less likely to occur. As a result, the friction on the surface of the coating layer is kept low. In particular, when the alloy exposure rate on the surface of the coating layer is 30% or more, the friction reduction effect of the Cu--Sn alloy can be sufficiently obtained.
　ここで、前記合金露出率は、５０％以下であるとよい。そのように、Ｃｕ－Ｓｎ合金とともにＳｎがある程度の露出率で露出した被覆層は、Ｃｕ層とＳｎ層を積層して加熱する方法により、簡便に製造することができる。また、被覆層の表面に、Ｓｎも十分に露出されることにより、Ｃｕ－Ｓｎ合金の寄与による摩擦低減効果と、接触抵抗の低減等、Ｓｎの寄与による効果が両立される。 Here, the alloy exposure rate is preferably 50% or less. In this way, a coating layer in which Sn is exposed at a certain exposure rate along with the Cu--Sn alloy can be easily manufactured by a method of laminating and heating a Cu layer and a Sn layer. Further, by sufficiently exposing Sn to the surface of the coating layer, the friction reduction effect due to the contribution of the Cu--Sn alloy and the effect due to the contribution of Sn, such as reduction in contact resistance, are both achieved.
　前記Ｓｎ部の平均の厚さが、０．１０μｍ以上０．３５μｍ以下であるとよい。また、前記合金部の平均の厚さが、０．２５μｍ以上０．４８μｍ以下であるとよい。すると、Ｃｕ層とＳｎ層を積層して加熱する方法により、高い合金露出率を有し、摩擦低減効果に優れた被覆層を製造することができる。 The average thickness of the Sn portion is preferably 0.10 μm or more and 0.35 μm or less. Further, the average thickness of the alloy portion is preferably 0.25 μm or more and 0.48 μm or less. Then, by a method of laminating and heating a Cu layer and a Sn layer, a coating layer having a high alloy exposure rate and an excellent friction reduction effect can be manufactured.
　前記基材は、ＣｕまたはＣｕ合金より構成され、前記基材と前記被覆層との間に、ＮｉまたはＮｉ合金より構成された拡散抑制層をさらに有するとよい。ＮｉおよびＮｉ合金よりなる拡散抑制層は、基材を構成するＣｕ等の原子が被覆層に拡散するのを効果的に抑制するものとなる。それにより、基材からの原子の拡散の影響を低減して、所定の合金露出率を示し、摩擦の低減された被覆層を安定して得ることができる。 It is preferable that the base material is made of Cu or a Cu alloy, and further includes a diffusion suppressing layer made of Ni or a Ni alloy between the base material and the coating layer. The diffusion suppressing layer made of Ni and Ni alloy effectively suppresses atoms such as Cu constituting the base material from diffusing into the coating layer. Thereby, it is possible to reduce the influence of atomic diffusion from the base material, exhibit a predetermined alloy exposure rate, and stably obtain a coating layer with reduced friction.
　本開示の電気接続端子は、前記端子材料を含んで構成され、少なくとも、相手方導電部材と接触する接点部において、前記基材の表面に、前記被覆層が形成されている。本開示の端子材料は、接点部の表面において合金部とＳｎ部の両方が露出され、かつ所定の合金露出率を有することで、接点部が、上記のように、表面の摩擦係数が低く抑えられたものとなる。その端子材料より電気接続端子を構成することで、接点部の摩擦が低減され、相手方端子等、相手方導電部材と接続する際の嵌合や挿入等、接点部の摺動を伴う操作に要する力を、小さく抑えることができる。 The electrical connection terminal of the present disclosure is configured to include the terminal material, and the coating layer is formed on the surface of the base material at least in the contact portion that contacts the other conductive member. In the terminal material of the present disclosure, both the alloy part and the Sn part are exposed on the surface of the contact part and have a predetermined alloy exposure ratio, so that the contact part can maintain a low surface friction coefficient as described above. It becomes what is given. By constructing the electrical connection terminal from this terminal material, the friction of the contact part is reduced, and the force required for operations that involve sliding of the contact part, such as fitting and insertion when connecting with a mating conductive member such as a mating terminal. can be kept small.
　ここで、前記電気接続端子は、プリント回路基板用オス端子として構成されているとよい。プリント回路基板用のオス端子は、端子形状に基材を成形してから、金属被覆層を形成する後めっき品として構成される場合が多いが、後めっき品においては、一次電流分布の影響で、被覆層の厚さに不均一な分布が生じ、オス端子の先端部等、尖った箇所に、厚い金属被覆層が形成されやすい。すると、先端部において、摩擦が大きくなる可能性がある。しかし、上記端子接続材料においては、３０％以上の合金露出率が確保されるため、被覆層が局所的に厚くなる箇所があっても、その箇所も含めて、表面の摩擦が効果的に低減され、低挿入力を達成することができる。 Here, the electrical connection terminal is preferably configured as a male terminal for a printed circuit board. Male terminals for printed circuit boards are often constructed as post-plated products in which a base material is formed into the terminal shape and then a metal coating layer is formed. , the thickness of the coating layer is unevenly distributed, and a thick metal coating layer is likely to be formed at sharp points such as the tips of male terminals. As a result, friction may increase at the tip. However, in the above terminal connection material, an alloy exposure rate of 30% or more is ensured, so even if there are areas where the coating layer is locally thick, surface friction is effectively reduced, including at those areas. low insertion force can be achieved.
［本開示の実施形態の詳細］
　以下に、本開示の実施形態について、図面を用いて詳細に説明する。本明細書において、単体金属には、不可避的不純物を含有する場合も含むものとする。また、合金には、特記しないかぎり、固溶体である場合も、金属間化合物を構成する場合も、含むものとする。さらに、ある金属を主成分とする合金とは、その金属元素が、組成中に５０原子％以上含まれる合金を指すものとする。 [Details of embodiments of the present disclosure]
Embodiments of the present disclosure will be described in detail below using the drawings. In this specification, the term "elementary metal" includes cases where it contains unavoidable impurities. Furthermore, unless otherwise specified, the term "alloy" includes both a solid solution and an intermetallic compound. Furthermore, an alloy containing a certain metal as a main component refers to an alloy in which the metal element is contained in the composition in an amount of 50 atomic % or more.
＜端子材料＞
　以下、本開示の実施形態にかかる端子材料について説明する。本開示の一実施形態にかかる端子材料１の断面を、図１に模式的に示す。 <Terminal material>
Terminal materials according to embodiments of the present disclosure will be described below. A cross section of a terminal material 1 according to an embodiment of the present disclosure is schematically shown in FIG.
（端子材料の概略）
　端子材料１は、基材２と、基材２の表面を被覆する被覆層４と、を有する。また、任意ではあるが、基材２と被覆層４の間に、拡散抑制層３を有することが好ましい。被覆層４は、端子材料１の最表面に露出していることが好ましいが、被覆層４の特性に著しい影響を与えない限り、被覆層４の表面に、有機層等の薄膜（不図示）を設けてもよい。 (Outline of terminal material)
The terminal material 1 includes a base material 2 and a coating layer 4 that covers the surface of the base material 2. Although optional, it is preferable to provide a diffusion suppressing layer 3 between the base material 2 and the coating layer 4. The coating layer 4 is preferably exposed on the outermost surface of the terminal material 1, but a thin film (not shown) such as an organic layer may be added to the surface of the coating layer 4 unless it significantly affects the characteristics of the coating layer 4. may be provided.
　基材２を構成する材料は、特に限定されるものではない。基材２としては、電気接続部材の構成材料として多用されているＣｕまたはＣｕ合金、ＡｌまたはＡｌ合金、ＦｅまたはＦｅ合金等を、好適に用いることができる。中でも、導電性や機械的特性に優れた金属であるＣｕまたはＣｕ合金を、好適に用いることができる。 The material constituting the base material 2 is not particularly limited. As the base material 2, Cu or Cu alloy, Al or Al alloy, Fe or Fe alloy, etc., which are often used as constituent materials of electrical connection members, can be suitably used. Among these, Cu or Cu alloy, which is a metal with excellent conductivity and mechanical properties, can be suitably used.
　拡散抑制層３は、Ｃｕ等、基材２を構成する原子が、被覆層４へと拡散するのを抑制する層である。基材の構成原子が被覆層４の表面に拡散し、酸化を受けると、被覆層４の表面の接触抵抗を上昇させるものとなる。また、拡散した基材の構成原子の影響により、被覆層４において、所望の組成や材料分布が得られなくなる可能性がある。そこで、基材２と被覆層４の間に拡散抑制層３を設けておくことで、基材の構成原子が被覆層４に拡散した場合に起こりうるそれらの現象を抑制することができる。拡散抑制層３は、基材の構成原子の拡散を抑制することができるものであれば、その種類を限定されるものではないが、高い拡散抑制効果を示す金属として、ＮｉまたはＮｉ合金を好適に適用することができる。拡散抑制層３の厚さは、特に限定されるものではないが、十分な拡散抑制効果を得る等の観点から、０．５μｍ以上とするとよい。一方、加工性等の観点から、その厚さは、２μｍ以下とするとよい。拡散抑制層３と、基材２および被覆層４の間の界面においては、拡散抑制層３を構成する金属と、それぞれ基材２および被覆層４を構成する金属が合金を形成した領域を、有していてもよい。 The diffusion suppression layer 3 is a layer that suppresses atoms such as Cu that constitute the base material 2 from diffusing into the coating layer 4. When constituent atoms of the base material diffuse to the surface of the coating layer 4 and undergo oxidation, the contact resistance of the surface of the coating layer 4 increases. Further, due to the influence of the diffused constituent atoms of the base material, there is a possibility that the desired composition and material distribution cannot be obtained in the coating layer 4. Therefore, by providing the diffusion suppressing layer 3 between the base material 2 and the coating layer 4, it is possible to suppress those phenomena that may occur when constituent atoms of the base material diffuse into the coating layer 4. The type of diffusion suppressing layer 3 is not limited as long as it can suppress the diffusion of constituent atoms of the base material, but Ni or Ni alloy is preferably used as a metal that exhibits a high diffusion suppressing effect. It can be applied to Although the thickness of the diffusion suppressing layer 3 is not particularly limited, it is preferably 0.5 μm or more from the viewpoint of obtaining a sufficient diffusion suppressing effect. On the other hand, from the viewpoint of workability, etc., the thickness is preferably 2 μm or less. At the interface between the diffusion suppressing layer 3, the base material 2, and the coating layer 4, a region where the metal forming the diffusion suppressing layer 3 and the metal forming the base material 2 and the coating layer 4, respectively, formed an alloy is formed. may have.
　被覆層４は、ＳｎとＣｕを含む金属層として構成されている。被覆層４は、均一な組成を有するものではなく、Ｃｕ－Ｓｎ合金より構成される合金部４１と、Ｓｎより構成されるＳｎ部４２と、をともに含んでいる。被覆層４は、不可避的不純物や、不可避的に基材２や拡散抑制層３から拡散する原子を除いて、ＳｎとＣｕのみより構成されることが好ましい。合金部４１およびＳｎ部４２は、それぞれ、不可避的不純物を除いて、それぞれ、Ｃｕ－Ｓｎ合金およびＳｎのみより構成されることが好ましいが、Ｃｕ－Ｓｎ合金およびＳｎ以外の不純物や添加元素を少量（例えば１０質量％以下）含有するものであってもよい。合金部４１を構成するＣｕ－Ｓｎ合金の組成は特に限定されるものではないが、Ｃｕ６Ｓｎ５なる金属間化合物を主成分として構成されていることが好ましい。以下に、被覆層４の構成の詳細について説明する。 The covering layer 4 is configured as a metal layer containing Sn and Cu. The coating layer 4 does not have a uniform composition and includes both an alloy part 41 made of a Cu--Sn alloy and an Sn part 42 made of Sn. It is preferable that the coating layer 4 is composed only of Sn and Cu, excluding unavoidable impurities and atoms that unavoidably diffuse from the base material 2 and the diffusion suppressing layer 3. It is preferable that the alloy part 41 and the Sn part 42 be composed of only a Cu-Sn alloy and Sn, respectively, excluding unavoidable impurities, but a small amount of impurities or additive elements other than the Cu-Sn alloy and Sn may be added. (for example, 10% by mass or less). Although the composition of the Cu--Sn alloy constituting the alloy portion 41 is not particularly limited, it is preferably composed of an intermetallic compound of Cu 6 Sn 5 as a main component. The details of the structure of the coating layer 4 will be explained below.
（被覆層の構成）
　図１に示すように、被覆層４は、Ｃｕ－Ｓｎ合金より構成される合金部４１と、Ｓｎより構成されるＳｎ部４２と、を有しており、合金部４１とＳｎ部４２の両方が、被覆層４の表面に露出している。被覆層４において、合金部４１は、山状に突出した凹凸構造を有する層として構成されている。そして、Ｓｎ部４２は、その凹凸構造の凹凸を埋めるようにして、合金部４１を被覆して形成されている。このように、凹凸構造を有するＣｕ－Ｓｎ合金よりなる合金部４１と、その表面を被覆するＳｎ部４２を備えた被覆層４は、後に説明するように、Ｃｕ層５とＳｎ層６をこの順に積層し、加熱することで、簡便に製造することができる。 (Composition of coating layer)
As shown in FIG. 1, the coating layer 4 has an alloy part 41 made of a Cu-Sn alloy and an Sn part 42 made of Sn, and both the alloy part 41 and the Sn part 42 is exposed on the surface of the coating layer 4. In the coating layer 4, the alloy portion 41 is configured as a layer having an uneven structure projecting like a mountain. The Sn portion 42 is formed by covering the alloy portion 41 so as to fill the unevenness of the uneven structure. As described above, the coating layer 4, which includes the alloy part 41 made of a Cu-Sn alloy having an uneven structure and the Sn part 42 covering the surface thereof, is formed by combining the Cu layer 5 and the Sn layer 6 as described later. It can be easily manufactured by sequentially laminating the layers and heating them.
　本実施形態においては、上記のように、被覆層４の最表面に、合金部４１と、Ｓｎ部４２がともに露出している。つまり、合金部４１の凹凸構造の凸部の頂上付近には、Ｓｎ部４２に被覆されておらず、Ｃｕ－Ｓｎ合金が露出した合金露出部４１ａが存在する。そして、被覆層４の表面において、合金部４１が占める面積率、つまり、表面全体の面積のうち、合金露出部４１ａが占める面積の割合として表される合金露出率が、３０％以上となっている。 In this embodiment, as described above, both the alloy part 41 and the Sn part 42 are exposed on the outermost surface of the coating layer 4. That is, near the top of the convex portion of the uneven structure of the alloy portion 41, there is an exposed alloy portion 41a where the Cu—Sn alloy is exposed and is not covered with the Sn portion 42. Then, on the surface of the coating layer 4, the area ratio occupied by the alloy part 41, that is, the alloy exposure ratio expressed as the ratio of the area occupied by the exposed alloy part 41a to the entire surface area is 30% or more. There is.
　Ｓｎ部４２は、低い接触抵抗を示し、端子材料１の表面において、相手方導電部材との間に、良好な電気接続特性を与えるものとなる。一方、合金部４１は、Ｃｕ－Ｓｎ合金が高硬度等の特性を有することにより、被覆層４において、摩擦を低く抑える（摩擦係数を低減する）役割を果たす。Ｓｎ部４２の下層に合金部４１が存在することで、Ｓｎ部４２の表面において、摩擦低減効果が得られる。そして、合金部４１が最表面に露出し、相手方導電部材と直接接触することで、摩擦の低減にさらに高い効果が得られる。本実施形態にかかる端子材料１においては、被覆層４の表面に、Ｓｎ部４２と、Ｃｕ－Ｓｎよりなる合金部４１とがともに露出していることにより、接触抵抗の低減等、Ｓｎ部４２による効果と、摩擦の低減等、合金部４１による効果とを、ともに享受することができる。 The Sn portion 42 exhibits low contact resistance and provides good electrical connection characteristics between the surface of the terminal material 1 and the other conductive member. On the other hand, the alloy portion 41 plays a role in keeping the friction low (reducing the coefficient of friction) in the coating layer 4 because the Cu--Sn alloy has characteristics such as high hardness. The presence of the alloy portion 41 in the lower layer of the Sn portion 42 provides a friction reduction effect on the surface of the Sn portion 42 . Further, since the alloy portion 41 is exposed on the outermost surface and comes into direct contact with the other conductive member, an even higher effect in reducing friction can be obtained. In the terminal material 1 according to the present embodiment, both the Sn portion 42 and the alloy portion 41 made of Cu-Sn are exposed on the surface of the coating layer 4, so that contact resistance can be reduced, etc. It is possible to enjoy both the effects of the alloy portion 41 and the effects of the alloy portion 41, such as reduction of friction.
　図６に示すように、合金部４１の表面の全体が、Ｓｎ部４２に被覆されているとすれば、合金部４１による摩擦低減効果が、十分に得られない。さらに、Ｓｎが軟らかく、凝着しやすい性質を有する金属であるため、図６のようにＳｎ部４２が厚く形成され、特に合金部４１の凹凸構造の谷に相当する箇所において、Ｓｎ部４２が大きな体積を占めることにより、相手方導電部材との間で摺動が行われた際に、Ｓｎ部４２が、掘り起こしや凝着を起こし、摩擦係数を上昇させるものとなる。 As shown in FIG. 6, if the entire surface of the alloy part 41 is covered with the Sn part 42, the friction reduction effect of the alloy part 41 cannot be sufficiently obtained. Furthermore, since Sn is a metal that is soft and easily adheres, the Sn portion 42 is formed thickly as shown in FIG. By occupying a large volume, when sliding is performed between the Sn portions 42 and the other conductive member, the Sn portions 42 cause digging and adhesion, thereby increasing the coefficient of friction.
　本実施形態にかかる端子材料１においては、上記のように、被覆層４の表面に、Ｓｎ部４２だけでなく合金部４１が露出しており、さらに合金露出率が３０％以上となっていることにより、特に摩擦低減効果に優れたものとなる。合金部４１が被覆層４の表面の３０％以上を占め、相手方導電部材と接触して、摺動時の摩擦現象に直接関与することで、合金部４１による摩擦低減の効果が高く発揮されるからである。また、合金部４１の露出率が高くなっていることは、合金部４１を被覆するＳｎ部４２の厚さが小さく抑えられており、被覆層４におけるＳｎ部４２の存在量が少なくなっていることを意味する。すると、Ｓｎ部４２の掘り起こしや凝着による摩擦の増大が起こりにくい。それらの結果、本実施形態にかかる端子材料１は、被覆層４の表面における摩擦の低減効果に優れたものとなる。この摩擦の低減は、被覆層４における合金部４１とＳｎ部４２の分布状態の結果として得られるものである。摩擦低減の効果をさらに高める観点から、合金露出率は、３５％以上、さらには４０％以上、４５％以上であると、より好ましい。 In the terminal material 1 according to the present embodiment, as described above, not only the Sn portion 42 but also the alloy portion 41 are exposed on the surface of the coating layer 4, and the alloy exposure rate is 30% or more. This results in a particularly excellent friction reduction effect. The alloy part 41 occupies 30% or more of the surface of the coating layer 4, comes into contact with the other conductive member, and is directly involved in the friction phenomenon during sliding, so that the friction reduction effect of the alloy part 41 is highly exhibited. It is from. Moreover, the fact that the exposure rate of the alloy part 41 is high means that the thickness of the Sn part 42 covering the alloy part 41 is kept small, and the amount of Sn part 42 present in the coating layer 4 is reduced. It means that. This makes it difficult for friction to increase due to digging up or adhesion of the Sn portion 42. As a result, the terminal material 1 according to the present embodiment has an excellent effect of reducing friction on the surface of the coating layer 4. This reduction in friction is obtained as a result of the distribution of the alloy portions 41 and Sn portions 42 in the coating layer 4. From the viewpoint of further enhancing the effect of reducing friction, the alloy exposure rate is more preferably 35% or more, more preferably 40% or more, or 45% or more.
　合金露出率の上限は、特に定められるものではないが、５０％以下、さらには４８％以下程度に抑えておくとよい。３０％以上かつそれらの上限以下の合金露出率は、凹凸構造を有する合金部４１の表面をＳｎ部４２が被覆する被覆層４の構造において、実現しやすく、下に説明するＣｕ層５とＳｎ層６を積層して加熱する方法により、簡便に得ることができる。また、合金露出率が上記上限以下に収まっていれば、Ｓｎ部４２の露出率も十分に大きく確保されることになるので、合金部４１による摩擦低減効果とともに、接触抵抗の低減等、Ｓｎ部４２によってもたらされる効果も、十分に得ることができる。 The upper limit of the alloy exposure rate is not particularly determined, but it is preferably kept at about 50% or less, and even 48% or less. An alloy exposure rate of 30% or more and below these upper limits can be easily achieved in the structure of the coating layer 4 in which the Sn part 42 covers the surface of the alloy part 41 having an uneven structure. It can be easily obtained by a method of laminating layers 6 and heating them. In addition, if the alloy exposure rate is below the above upper limit, the exposure rate of the Sn portion 42 will be ensured sufficiently large, so that in addition to the friction reduction effect of the alloy portion 41, the Sn portion The effects brought about by 42 can also be fully obtained.
　被覆層４においては、上記の合金露出率が与えられれば、Ｓｎ部４２および合金部４１の厚さや分布状態の詳細は、特に限定されるものではない。しかし、３０％以上、そして好ましくは５０％以下の合金露出率を有する被覆層４を与えやすく、またＣｕ層５とＳｎ層６を積層して加熱する方法で形成しやすいなどの点から、被覆層４は、以下のような構成を有することが好ましい。 In the coating layer 4, the details of the thickness and distribution of the Sn portion 42 and the alloy portion 41 are not particularly limited as long as the above alloy exposure rate is given. However, since it is easy to provide the coating layer 4 having an alloy exposure rate of 30% or more and preferably 50% or less, and it is easy to form the coating layer 4 by laminating and heating the Cu layer 5 and the Sn layer 6, the coating It is preferable that layer 4 has the following configuration.
　まず、被覆層４において、Ｓｎ部４２の厚さは、合金部４１の厚さ（平均値；以下においても同様）よりも小さいことが好ましい。Ｓｎ部４２および合金部４１の厚さそのものは、特に限定されるものではない。しかし、Ｓｎ部４２の厚さ（平均値）は、０．３５μｍ以下、さらには０．２５μｍ以下、０．２０μｍ以下であるとよい。すると、高い合金露出率を確保しやすいとともに、Ｓｎ部４２の掘り起こしや凝着による摩擦の増大を効果的に抑制することができる。一方、Ｓｎ部４２の厚さ（平均値）は、０．１０μｍ以上、さらには０．１２μｍ以上であるとよい。すると、Ｓｎ部４２による接触抵抗低減等の効果も、十分に得やすくなる。合金部４１の厚さ（平均値）としては、十分な合金露出率を確保し、摩擦低減の効果を得やすくする観点から、０．２５μｍ以上、さらには０．３０μｍ以上、０．３５μｍ以上であることが好ましい。一方、合金露出率を高めすぎないようにする観点から、合金部４１の厚さは、０．４８μｍ以下、さらには０．４５μｍ以下であるとよい。 First, in the coating layer 4, the thickness of the Sn portion 42 is preferably smaller than the thickness (average value; the same applies below) of the alloy portion 41. The thicknesses of the Sn portion 42 and the alloy portion 41 are not particularly limited. However, the thickness (average value) of the Sn portion 42 is preferably 0.35 μm or less, more preferably 0.25 μm or less, or 0.20 μm or less. This makes it easy to ensure a high alloy exposure rate, and it is also possible to effectively suppress an increase in friction due to digging up or adhesion of the Sn portion 42. On the other hand, the thickness (average value) of the Sn portion 42 is preferably 0.10 μm or more, more preferably 0.12 μm or more. Then, effects such as contact resistance reduction by the Sn portion 42 can be sufficiently easily obtained. The thickness (average value) of the alloy portion 41 should be 0.25 μm or more, further 0.30 μm or more, or 0.35 μm or more, from the viewpoint of ensuring a sufficient alloy exposure rate and making it easier to obtain the effect of reducing friction. It is preferable that there be. On the other hand, from the viewpoint of not increasing the alloy exposure rate too much, the thickness of the alloy portion 41 is preferably 0.48 μm or less, and more preferably 0.45 μm or less.
　被覆層４の表面に露出した合金部４１およびＳｎ部４２の具体的な分布形状は、特に限定されるものではないが、合金部４１とＳｎ部４２の両方の特性を有効に利用する観点から、端子における接点部等、相手方導電部材と接触する箇所に、合金部４１とＳｎ部４２が両方とも、ある程度の面積を占めて共存するように、分布していればよい。 The specific distribution shape of the alloy part 41 and the Sn part 42 exposed on the surface of the coating layer 4 is not particularly limited, but from the viewpoint of effectively utilizing the characteristics of both the alloy part 41 and the Sn part 42. It is only necessary that the alloy portion 41 and the Sn portion 42 are distributed so that they both occupy a certain amount of area and coexist at a location that contacts the other conductive member, such as a contact portion of a terminal.
（被覆層の形成方法）
　被覆層４の形成方法は、特に限定されるものではないが、ＣｕとＳｎの合金化による方法を、好適に用いることができる。つまり、図２に示したように、適宜、拡散抑制層３を形成した基材２の表面に、Ｃｕ層５とＳｎ層６をこの順に積層した原料材１’を準備する。Ｃｕ層５およびＳｎ層６は、電解めっきによって形成することが好ましい。次に、この原料材１’をＳｎの融点以上の温度で加熱する（リフロー処理）。加熱により、ＣｕとＳｎの合金化が起こり、Ｃｕ－Ｓｎ合金よりなる合金部４１が形成される。そして、合金化に費やされなかったＳｎが、Ｓｎ部４２となる。このように、Ｃｕ層５とＳｎ層６を積層して加熱することで、特別な操作を行わなくても、合金部４１が凹凸構造を有する層として形成され、その凹凸を埋めるようにＳｎ部４２が合金部４１を被覆した被覆層４を形成することができる。 (Method for forming coating layer)
The method of forming the coating layer 4 is not particularly limited, but a method of alloying Cu and Sn can be suitably used. That is, as shown in FIG. 2, a raw material 1' is prepared in which a Cu layer 5 and a Sn layer 6 are laminated in this order on the surface of a base material 2 on which a diffusion suppressing layer 3 is appropriately formed. The Cu layer 5 and the Sn layer 6 are preferably formed by electrolytic plating. Next, this raw material 1' is heated at a temperature equal to or higher than the melting point of Sn (reflow treatment). By heating, alloying of Cu and Sn occurs, and an alloy portion 41 made of a Cu--Sn alloy is formed. Then, the Sn that was not spent on alloying becomes the Sn portion 42. In this way, by laminating and heating the Cu layer 5 and the Sn layer 6, the alloy portion 41 is formed as a layer having an uneven structure without any special operation, and the Sn layer is formed to fill the unevenness. 42 can form a coating layer 4 that covers the alloy part 41.
　被覆層４における合金露出率は、例えば、原料材１’におけるＣｕ層５およびＳｎ層６の厚さによって制御することができる。合金露出率を十分に高める観点から、Ｓｎ層６の厚さは、Ｃｕ層５の厚さに対して、６．０倍以下、さらには５．０倍以下、４．０倍以下に留めておくことが好ましい。また、Ｓｎ層６の厚さを、０．６０μｍ以下、０．５０μｍ以下、０．４０μｍ以下としておくとよい。一方で、ＳｎとＣｕの合金化を十分に進めるとともに、合金化に費やされないＳｎ部４２を十分に残す観点から、Ｓｎ層６の厚さは、Ｃｕ層５の厚さに対して、１．０倍以上、さらには２．０倍以上、３．０倍以上としておくとよい。また、Ｓｎ層６の厚さを、０．１０μｍ以上、０．２０μｍ以上、０．３０μｍ以上としておくとよい。Ｃｕ層５の厚さは、０．０５μｍ以上、また０．１０μｍ以上としておくとよく、一方で０．２０μｍ以下としておくとよい。なお、原料材１’におけるＳｎ層６とＣｕ層５の厚さの比率は、合金形成後の被覆層４において、被覆層４全体に含まれるＳｎ原子とＣｕ原子の原子数比を、ＳｎとＣｕの体積比に換算した値として、端子材料１の構成から確認することができる。 The alloy exposure rate in the coating layer 4 can be controlled, for example, by the thicknesses of the Cu layer 5 and the Sn layer 6 in the raw material 1'. From the viewpoint of sufficiently increasing the alloy exposure rate, the thickness of the Sn layer 6 should be kept at 6.0 times or less, further 5.0 times or less, and 4.0 times or less than the Cu layer 5. It is preferable to leave it there. Further, the thickness of the Sn layer 6 is preferably set to 0.60 μm or less, 0.50 μm or less, or 0.40 μm or less. On the other hand, from the viewpoint of sufficiently advancing the alloying of Sn and Cu and leaving enough Sn portion 42 that is not spent on alloying, the thickness of the Sn layer 6 is set to 1 It is preferable to set it to .0 times or more, further 2.0 times or more, or 3.0 times or more. Further, the thickness of the Sn layer 6 is preferably set to 0.10 μm or more, 0.20 μm or more, or 0.30 μm or more. The thickness of the Cu layer 5 is preferably 0.05 μm or more, or 0.10 μm or more, and preferably 0.20 μm or less. In addition, the ratio of the thickness of the Sn layer 6 and the Cu layer 5 in the raw material 1' is the atomic ratio of Sn atoms and Cu atoms contained in the entire coating layer 4 in the coating layer 4 after alloy formation. The value converted to the volume ratio of Cu can be confirmed from the configuration of the terminal material 1.
＜電気接続端子＞
　本開示の一実施形態にかかる電気接続端子は、上記で説明した本開示の実施形態にかかる端子材料１を含んで構成される。電気接続端子において、被覆層４は、少なくとも、相手方端子等、相手方導電部材と接触する接点部に形成されている。被覆層４（および拡散抑制層３）は、少なくとも接点部に形成されていれば、電気接続端子の表面の全域に形成されていても、一部の領域のみに形成されていてもよい。 <Electrical connection terminal>
An electrical connection terminal according to an embodiment of the present disclosure is configured to include the terminal material 1 according to the embodiment of the present disclosure described above. In the electrical connection terminal, the coating layer 4 is formed at least on a contact portion such as a mating terminal that comes into contact with a mating conductive member. The covering layer 4 (and the diffusion suppressing layer 3) may be formed on the entire surface of the electrical connection terminal or only on a part of the surface as long as it is formed on at least the contact portion.
　電気接続端子の具体的な種類および形状は、特に限定されるものではないが、プリント回路基板（ＰＣＢ）用オス端子である形態を、好適に例示することができる。図３に、ＰＣＢ用オス端子１０の構造を例示する。ＰＣＢ用オス端子１０は、長尺状の電気接続端子であり、一端に、プリント回路基板のスルーホールに挿入して接続される基板接続部１１を有し、他端に、相手方接続端子と挿入等によって接続される嵌合型オス端子の形状をとった端子接続部１２を有している。このＰＣＢ用オス端子１０において、接点部となる基板接続部１１および端子接続部１２を少なくとも含む箇所において、基材２の表面に被覆層４が設けられる。好ましくは、表面全域に被覆層４が形成されているとよい。 The specific type and shape of the electrical connection terminal are not particularly limited, but a preferred example is a male terminal for a printed circuit board (PCB). FIG. 3 illustrates the structure of the PCB male terminal 10. The PCB male terminal 10 is a long electrical connection terminal, and has a board connection part 11 at one end that is inserted into a through hole of a printed circuit board and connected, and the other end is inserted into a mating connection terminal. It has a terminal connection part 12 in the shape of a fitting type male terminal that is connected by a connector or the like. In this PCB male terminal 10, a coating layer 4 is provided on the surface of the base material 2 at a location that includes at least the board connection portion 11 and the terminal connection portion 12, which serve as contact portions. Preferably, the coating layer 4 is formed over the entire surface.
　上記で説明したように、本開示の実施形態にかかる端子材料１は、合金部４１とＳｎ部４２をともに被覆層４の表面に露出させ、３０％以上の合金露出率を有することにより、摩擦低減効果に優れたものであり、ＰＣＢ用オス端子１０をはじめ、本開示の実施形態にかかる端子材料１より構成された電気接続端子は、接点部において、その摩擦低減効果を享受することができる。つまり、例えば端子接続部１１を挿入されるメス端子のような相手方導電部材と、摺動を伴って挿入・嵌合させる際に要する力である挿入力（または嵌合力；本明細書において同じ）を、小さく抑えることができる。ＰＣＢ用オス端子１０は、複数をコネクタハウジングに固定したコネクタの状態で、一括して挿入・嵌合を行う場合も多く、各端子１０の挿入力の低減が、コネクタ全体として大きな挿入力低減効果につながる。 As explained above, in the terminal material 1 according to the embodiment of the present disclosure, both the alloy part 41 and the Sn part 42 are exposed on the surface of the coating layer 4, and by having an alloy exposure rate of 30% or more, friction is reduced. It has an excellent friction reduction effect, and electrical connection terminals made of the terminal material 1 according to the embodiment of the present disclosure, including the male terminal 10 for PCB, can enjoy the friction reduction effect at the contact portion. . That is, for example, insertion force (or fitting force; the same in this specification) is the force required when inserting and fitting the terminal connecting part 11 with a mating conductive member such as a female terminal with sliding movement. can be kept small. A plurality of male PCB terminals 10 are often inserted and mated all at once in the state of a connector fixed to a connector housing, and reducing the insertion force of each terminal 10 has a large insertion force reduction effect for the connector as a whole. Leads to.
　一般に、ＰＣＢ用オス端子は、打ち抜き加工等により、基材を所定の端子形状に成形したうえで、基材の表面にめっきによって金属被覆層を形成する場合が多い（後めっき）。このように、後めっきによって形成される電気接続端子においては、めっき時の一次電流分布の影響により、基板接続部１１や端子接続部１２の先端のように、尖った箇所の金属被覆層の厚さが他の箇所よりも大きくなった不均一な分布が、金属被覆層に生じやすい。Ｓｎ層等、凝着や掘り起こしを起こしやすい金属被覆層が接点部に厚く形成されると、端子挿入力の上昇につながる。しかし、本開示の実施形態にかかる端子材料１より構成された電気接続端子においては、被覆層４の表面に、Ｓｎ部４２とともに合金部４１が露出し、かつ合金露出率が３０％以上とされていることにより、接点部を含む箇所に厚い被覆層４が形成されたとしても、合金部４１の寄与により、挿入力低減の効果が得られる。 In general, male terminals for PCBs are often formed by forming a base material into a predetermined terminal shape by punching or the like, and then forming a metal coating layer on the surface of the base material by plating (post-plating). In this way, in electrical connection terminals formed by post-plating, the thickness of the metal coating layer at sharp points such as the tips of the board connection part 11 and the terminal connection part 12 is affected by the primary current distribution during plating. A non-uniform distribution in which the thickness is larger than other parts is likely to occur in the metal coating layer. If a metal coating layer such as a Sn layer that is prone to adhesion or digging is formed thickly at the contact portion, the terminal insertion force will increase. However, in the electrical connection terminal made of the terminal material 1 according to the embodiment of the present disclosure, the alloy portion 41 is exposed together with the Sn portion 42 on the surface of the coating layer 4, and the alloy exposure rate is 30% or more. As a result, even if a thick coating layer 4 is formed at a portion including the contact portion, the effect of reducing the insertion force can be obtained due to the contribution of the alloy portion 41.
　以下、実施例を示す。なお、本発明はこれら実施例によって限定されるものではない。ここでは、合金露出率と端子挿入力の関係について検証した。以下では、特記しない限り、試料の作製および評価は、大気中、室温にて行っている。 Examples are shown below. Note that the present invention is not limited to these Examples. Here, we verified the relationship between alloy exposure rate and terminal insertion force. In the following, unless otherwise specified, samples were prepared and evaluated in the atmosphere at room temperature.
＜試料の作製＞
　構造評価用の試料として、平板状の銅合金基材の表面に、厚さ１μｍのＮｉの拡散抑制層を形成したうえで、Ｃｕ層とＳｎ層をこの順に形成し、原料材を得た。各金属層の形成は、電解めっき法によって行った。Ｃｕ層５の厚さは、０．１μｍとし、Ｓｎ層の厚さは、下の表１に示したとおりとした。続いて、この原料材を加熱してリフロー処理を行い、ＣｕとＳｎの合金化によって、合金部とＳｎ部を含む被覆層を形成した。 <Preparation of sample>
As a sample for structural evaluation, a Ni diffusion suppressing layer with a thickness of 1 μm was formed on the surface of a flat copper alloy base material, and then a Cu layer and a Sn layer were formed in this order to obtain a raw material. Each metal layer was formed by electrolytic plating. The thickness of the Cu layer 5 was 0.1 μm, and the thickness of the Sn layer was as shown in Table 1 below. Subsequently, this raw material was heated and subjected to a reflow treatment to form a coating layer including an alloy part and a Sn part by alloying Cu and Sn.
　別途、端子挿入力を評価するための試料として、銅合金基材を、図３に示したＰＣＢ用オス端子の形状に打ち抜き加工したものの表面に、上記と同様に、Ｎｉ層、Ｃｕ層、Ｓｎ層の形成とリフロー処理を行うことで、端子表面に被覆層を形成した。端子としては、０．６４ｍｍ角のものを用いた。この作製した端子をコネクタハウジングにセットして、ＰＣＢ用の多極コネクタを模した４０極の試験用のモデルコネクタを作製した。 Separately, as a sample for evaluating the terminal insertion force, a copper alloy base material was punched into the shape of the male terminal for PCB shown in Fig. 3, and the surface was coated with a Ni layer, a Cu layer, and a Sn layer in the same manner as above. A coating layer was formed on the terminal surface by layer formation and reflow treatment. A 0.64 mm square terminal was used as the terminal. The produced terminals were set in a connector housing to produce a 40-pole test model connector imitating a multi-pole connector for PCB.
＜評価方法＞
（１）被覆層の構造の評価
　構造評価用の板状の試料の断面に対して、走査電子顕微鏡（ＳＥＭ）観察を行い、凹凸構造を有する合金部と、その合金部を被覆するＳｎ部とを含んだ構造が被覆層に形成されていることを確認した。そして、Ｓｎ部および合金部の厚さ（それぞれ平均値）を、断面のＳＥＭ観察像において計測した。 <Evaluation method>
(1) Evaluation of the structure of the coating layer Scanning electron microscopy (SEM) observation was performed on the cross section of a plate-shaped sample for structural evaluation. It was confirmed that a structure containing the following was formed in the coating layer. Then, the thicknesses (each average value) of the Sn part and the alloy part were measured in the SEM observation image of the cross section.
　さらに、試料の表面に対してもＳＥＭ観察を行い、合金露出率を評価した。この際、得られたＳＥＭ観察像を２値化したうえで、合金部に相当する箇所が観察像全体において占める箇所の面積率を見積もり、合金露出率とした。 Furthermore, SEM observation was performed on the surface of the sample to evaluate the alloy exposure rate. At this time, the obtained SEM observation image was binarized, and the area ratio of the area corresponding to the alloy portion in the entire observation image was estimated and determined as the alloy exposure rate.
（２）挿入力の評価
　オス型コネクタのモデルとして上記で作製したモデルコネクタについて、対応するメス端子がコネクタハウジングにセットされたメス型コネクタと嵌合させて、コネクタ嵌合力を計測した。この際、コネクタ嵌合力は、モデルコネクタを摺動させながらメス型コネクタと嵌合させるのに要する力の最大値として計測した。 (2) Evaluation of insertion force For the model connector produced above as a male connector model, the corresponding female terminal was fitted into a female connector set in the connector housing, and the connector fitting force was measured. At this time, the connector fitting force was measured as the maximum value of the force required to fit the model connector to the female connector while sliding it.
＜評価結果＞
　図４に、原料材のＳｎ層の厚さを異ならせた複数の試料について、表面を観察したＳＥＭ像を、２値化像および合金露出率の値とともに示す。ＳＥＭ像中のスケールバーは、５０μｍを示している。 <Evaluation results>
FIG. 4 shows SEM images of the surfaces of a plurality of samples in which the thickness of the Sn layer of the raw material was varied, together with the binarized image and the value of the alloy exposure rate. The scale bar in the SEM image indicates 50 μm.
　ＳＥＭ像において、暗く観察されている領域がＣｕ－Ｓｎ合金よりなる合金部、明るく観察されている領域がＳｎ部にあたる。ＳＥＭ像より、各試料の表面に、合金部とＳｎ部の両方が混在して露出していることが確認される。合金露出率は、試料によって異なっており、原料材のＳｎ層の膜厚が比較的小さい領域で、合金露出率が高くなっている傾向がある。 In the SEM image, the region observed darkly corresponds to the alloy part made of a Cu-Sn alloy, and the region observed brightly corresponds to the Sn part. From the SEM images, it is confirmed that both the alloy part and the Sn part are mixed and exposed on the surface of each sample. The alloy exposure rate varies depending on the sample, and the alloy exposure rate tends to be high in regions where the Sn layer of the raw material has a relatively small thickness.
　次に、下の表１に、各試料について、原料材のＳｎ層の厚さとともに、合金露出率および各部の厚さ、およびコネクタ嵌合力の測定値をまとめる。なお、表１および後述する図５に表示している合金露出率の値は、複数の観察箇所において得た図４と同様の計測結果を平均したものである。 Next, Table 1 below summarizes the thickness of the Sn layer of the raw material, the alloy exposure rate, the thickness of each part, and the measured values of the connector fitting force for each sample. The alloy exposure rate values shown in Table 1 and FIG. 5, which will be described later, are the average of the same measurement results as in FIG. 4 obtained at a plurality of observation points.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表１によると、おおむね、原料材のＳｎ層を厚くするほど、得られる被覆層において、Ｓｎ部および合金部の厚さがともに大きくなっているが、合金部に対するＳｎ部の厚さの比率（［Ｓｎ部の厚さ］／［合金部の厚さ］×１００％）も大きくなっている。合金露出率は、図４にも示したとおり、原料材のＳｎ層が厚くなるほど、小さくなる傾向がある。コネクタ嵌合力は、試料１～４のＳｎ層の厚さが比較的小さい領域ではあまり変化していないが、Ｓｎ層の厚さがそれらよりも大きい試料５，６では、Ｓｎ層の厚さの増大に伴って、大きくなっている。 According to Table 1, as the Sn layer of the raw material becomes thicker, both the Sn part and the alloy part become thicker in the resulting coating layer, but the ratio of the thickness of the Sn part to the alloy part ( [Thickness of Sn portion]/[Thickness of alloy portion]×100%) is also increased. As shown in FIG. 4, the alloy exposure rate tends to decrease as the Sn layer of the raw material becomes thicker. The connector fitting force does not change much in the areas where the Sn layer thickness is relatively small in Samples 1 to 4, but in Samples 5 and 6 where the Sn layer thickness is larger than those, As it grows, it becomes larger.
　さらに、図５に、表１に示したデータについて、合金露出率およびコネクタ嵌合力の値を、被覆層におけるＳｎ部の平均の厚さに対してプロットしている。合金露出率はダイヤ印にて表示しており、その値を左軸に示している。コネクタ嵌合力は丸印にて表示しており、その値を右軸に示している。 Further, in FIG. 5, the values of the alloy exposure rate and the connector fitting force are plotted against the average thickness of the Sn portion in the coating layer for the data shown in Table 1. The alloy exposure rate is indicated by a diamond, and its value is shown on the left axis. The connector fitting force is indicated by a circle, and its value is shown on the right axis.
　図５によると、表１で見られた傾向が、明確に確認される。つまり、Ｓｎ部の厚さが大きくなるほど、合金露出率は、ほぼ単調減少の形態をとって、減少している。これに対し、コネクタ嵌合力は、Ｓｎ部の厚さが０．４０μｍ未満の領域では、ほぼ平坦に推移しているのに対し、それよりもＳｎ部の厚さが大きい領域では、Ｓｎ部の厚さの増大に伴って、上昇している。合金露出率とコネクタ嵌合力を対照すると、おおむね、合金露出率が３０％以下の領域で、コネクタ嵌合力が平坦に低値を推移している。このことから、合金露出率を３０％以下に抑えておけば、被覆層の表面における摩擦を低減し、電気接続端子において、端子挿入力を小さく抑えることができると言える。 According to Figure 5, the trends seen in Table 1 are clearly confirmed. In other words, as the thickness of the Sn portion increases, the alloy exposure rate decreases almost monotonically. On the other hand, the connector mating force remains almost flat in the region where the thickness of the Sn part is less than 0.40 μm, but in the region where the thickness of the Sn part is larger than that, It increases as the thickness increases. Comparing the alloy exposure rate and the connector fitting force, the connector fitting force remains flat and low in the region where the alloy exposure rate is 30% or less. From this, it can be said that by suppressing the alloy exposure rate to 30% or less, the friction on the surface of the coating layer can be reduced and the terminal insertion force in the electrical connection terminal can be suppressed to a small level.
　以上、本開示の実施の形態について詳細に説明したが、本発明は上記実施の形態に何ら限定されるものではなく、本発明の要旨を逸脱しない範囲で種々の改変が可能である。 Although the embodiments of the present disclosure have been described in detail above, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the gist of the present invention.
１　　　　端子材料
１’　　　原料材
１０　　　ＰＣＢ用オス端子
１１　　　基板接続部
１２　　　端子接続部
２　　　　基材
３　　　　拡散抑制層
４　　　　被覆層
４１　　　合金部
４１ａ　　合金露出部
４２　　　Ｓｎ部
５　　　　Ｃｕ層
６　　　　Ｓｎ層
９　　　　Ｓｎ部が厚く形成された端子材料 1 Terminal material 1' Raw material 10 Male terminal for PCB 11 Board connection part 12 Terminal connection part 2 Base material 3 Diffusion suppression layer 4 Covering layer 41 Alloy part 41a Alloy exposed part 42 Sn part 5 Cu layer 6 Sn layer 9 Sn part Thick terminal material

Claims (7)

  1. 　基材と、
    　前記基材の表面を被覆する被覆層と、を有し、
    　前記被覆層は、
    　Ｃｕ－Ｓｎ合金より構成される合金部と、
    　Ｓｎより構成されるＳｎ部と、を有し、
    　前記被覆層の表面には、前記合金部と前記Ｓｎ部の両方が露出され、
    　前記被覆層の表面において前記合金部が占める面積率を示す合金露出率が、３０％以上である、端子材料。     base material and
    a coating layer that covers the surface of the base material,
    The coating layer is
    An alloy part made of a Cu-Sn alloy,
    and an Sn portion composed of Sn,
    Both the alloy part and the Sn part are exposed on the surface of the coating layer,
    The terminal material has an alloy exposure ratio, which indicates the area ratio occupied by the alloy portion on the surface of the coating layer, of 30% or more.
  2. 　前記合金露出率は、５０％以下である、請求項１に記載の端子材料。 The terminal material according to claim 1, wherein the alloy exposure rate is 50% or less.
  3. 　前記Ｓｎ部の平均の厚さが、０．１０μｍ以上０．３５μｍ以下である、請求項１または請求項２に記載の端子材料。 The terminal material according to claim 1 or 2, wherein the average thickness of the Sn portion is 0.10 μm or more and 0.35 μm or less.
  4. 　前記合金部の平均の厚さが、０．２５μｍ以上０．４８μｍ以下である、請求項３に記載の端子材料。 The terminal material according to claim 3, wherein the average thickness of the alloy portion is 0.25 μm or more and 0.48 μm or less.
  5. 　前記基材は、ＣｕまたはＣｕ合金より構成され、
    　前記基材と前記被覆層との間に、ＮｉまたはＮｉ合金より構成された拡散抑制層をさらに有する、請求項１から請求項４のいずれか１項に記載の端子材料。     The base material is made of Cu or a Cu alloy,
    The terminal material according to any one of claims 1 to 4, further comprising a diffusion suppressing layer made of Ni or a Ni alloy between the base material and the coating layer.
  6. 　請求項１から請求項５のいずれか１項に記載の端子材料を含んで構成され、少なくとも、相手方導電部材と接触する接点部において、前記基材の表面に、前記被覆層が形成されている、電気接続端子。 The base material is configured to include the terminal material according to any one of claims 1 to 5, and the coating layer is formed on the surface of the base material at least in the contact portion that comes into contact with the other conductive member. , electrical connection terminals.
  7. 　プリント回路基板用オス端子として構成されている、請求項６に記載の電気接続端子。 The electrical connection terminal according to claim 6, configured as a male terminal for a printed circuit board.
PCT/JP2023/010836 2022-03-22 2023-03-20 Terminal material and electrical connection terminal WO2023182259A1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009005041A1 (en) * 2007-06-29 2009-01-08 The Furukawa Electric Co., Ltd. Fretting-resistant connector and process for manufacturing the same
JP2016211031A (en) * 2015-05-07 2016-12-15 Ｄｏｗａメタルテック株式会社 Sn-PLATED MATERIAL AND METHOD OF PRODUCING THE SAME
WO2018074256A1 (en) * 2016-10-17 2018-04-26 古河電気工業株式会社 Conductive bar material
JP2020105574A (en) * 2018-12-27 2020-07-09 三菱マテリアル株式会社 Anticorrosive terminal material, terminal and wire terminal structure

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009005041A1 (en) * 2007-06-29 2009-01-08 The Furukawa Electric Co., Ltd. Fretting-resistant connector and process for manufacturing the same
JP2016211031A (en) * 2015-05-07 2016-12-15 Ｄｏｗａメタルテック株式会社 Sn-PLATED MATERIAL AND METHOD OF PRODUCING THE SAME
WO2018074256A1 (en) * 2016-10-17 2018-04-26 古河電気工業株式会社 Conductive bar material
JP2020105574A (en) * 2018-12-27 2020-07-09 三菱マテリアル株式会社 Anticorrosive terminal material, terminal and wire terminal structure

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