JP2007277715A - Plated material and electric/electronic component using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plated material suitable for the sliding part of a connection terminal and an electric/electronic component such as a fitting type multipolar connector whose inserting/extracting properties are improved by using the plated material. <P>SOLUTION: The plated material 7 is obtained by arranging a base layer 2 composed of Ni or the like on an electrically-conductive substrate 1, a copper-based layer 3 composed of Cu or a Cu alloy on the base layer, an intermediate layer 4 composed of a Cu-Sn intermetallic compound on the copper-based layer, a tin-based layer 5 composed of Sn or a Sn alloy on the intermediate layer, in this order, and an outermost layer 6 composed of the Cu-Sn intermetallic compound on the tin-based layer. When the plated material 7 is used as a material for the sliding surface of a terminal or the like, the inserting/extracting properties of the terminal can be improved advantageously since the outermost layer 6 is composed of the hard Cu-Sn intermetallic compound and a fretting phenomenon is hardly caused even when the contact pressure between terminals is made low. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a plating material suitable for a sliding portion of a connection terminal and the like, and an electrical / electronic component such as a fitting-type multipolar connector whose insertion / removability is improved by using the plating material.

  A plating material in which a plating layer such as tin (Sn) or tin alloy is provided on a conductive substrate such as copper (Cu) or a copper alloy (hereinafter referred to as a substrate as appropriate) has excellent conductivity and strength of the substrate. In addition, it is known as a high-performance conductor having excellent electrical connectivity, corrosion resistance, and solderability of the plating layer, and is widely used for various terminals and connectors. This plating material is usually nickel (which has a barrier function on the substrate) in order to prevent the alloy component of the substrate such as zinc (Zn) (hereinafter, appropriately referred to as a substrate component) from diffusing into the plating layer. Ni), cobalt (Co), iron (Fe), and the like are subjected to base plating.

  In a high temperature environment such as in an automobile engine room, the Sn plating layer on the surface of the terminal has an oxide film formed on the surface because Sn is easily oxidizable, but this oxide film is brittle and breaks when the terminal is connected. The unoxidized Sn plating layer is exposed and good electrical connectivity is obtained.

  By the way, in recent years, with the progress of electronic control, the mating connector has become multipolar, so a great deal of force is required when inserting and removing the male terminal group and the female terminal group, especially in a narrow space such as in the engine room of an automobile. Since insertion / extraction work is difficult, reduction of the insertion / extraction force is strongly demanded.

  As a method of reducing the insertion / extraction force, a method of reducing the contact pressure between the terminals by thinning the Sn plating layer on the surface of the connector terminal is conceivable, but this method causes the flapping between the contact surfaces of the terminals because the Sn plating layer is soft. Tinging phenomenon may occur, resulting in poor continuity between terminals.

  The fretting phenomenon is that the soft Sn plating layer on the surface of the terminal wears and oxidizes due to fine sliding that occurs between the contact surfaces of the terminal due to vibration, temperature change, etc., and becomes a wear powder having a large specific resistance. When this phenomenon occurs between terminals, a connection failure occurs. This phenomenon is more likely to occur as the contact pressure between the terminals is lower.

In order to prevent the fretting phenomenon, a method (Patent Documents 1 and 2) for forming a Cu—Sn intermetallic compound layer such as hard Cu ₆ Sn ₅ on which a fretting phenomenon hardly occurs has been proposed. However, this method has a problem that a base material component such as Cu diffuses in a large amount in the Cu—Sn intermetallic compound layer and the Cu—Sn intermetallic compound layer becomes brittle.

  The plating material (Patent Document 3) in which the Ni layer is provided between the base and the Cu—Sn intermetallic compound layer to prevent the diffusion of the base component does not exist between the Ni layer and the Cu—Sn intermetallic compound layer. Therefore, when this material is produced by plating Ni, Cu, and Sn in this order on a substrate and heat-treating them, the plating thickness of the plated laminate is determined based on the stoichiometric ratio of Cu and Sn. It was necessary to design strictly and perform the heat treatment based on thorough management, and much labor was required for manufacturing.

JP 2000-212720 A JP 2000-226645 A JP 2004-68026 A

  An object of the present invention is to provide a plating material suitable for a sliding portion of a connection terminal and the like, and an electric / electronic component such as a fitting type multipolar connector whose insertion / removability is improved by using the plating material.

  The invention described in claim 1 is a base layer made of any one of nickel, nickel alloy, cobalt, cobalt alloy, iron, and iron alloy on a conductive substrate, and a copper-based layer made of copper or a copper alloy thereon. And an intermediate layer made of a Cu—Sn intermetallic compound, a tin-based layer made of tin or a tin alloy thereon, and an outermost layer made of a Cu—Sn intermetallic compound thereon. Plating material to be used.

  According to the second aspect of the present invention, there is provided a base layer made of any one of nickel, nickel alloy, cobalt, cobalt alloy, iron, and iron alloy on a conductive substrate, and an intermediate made of a Cu—Sn intermetallic compound thereon. A plating material comprising: a layer, a tin-based layer made of tin or a tin alloy thereon, and an outermost layer made of a Cu—Sn intermetallic compound thereon.

The invention described in claim 3 is a plating material according to claim 1 or 2, wherein the intermediate layer and the outermost layer of the Cu-Sn intermetallic compound is characterized by mainly comprising Cu 3 _Sn compound.

The invention described in claim 4 is a plating material according to claim 1 or 2, wherein the intermediate layer and the outermost layer of the Cu-Sn intermetallic compound is characterized by mainly containing Cu ₆ Sn ₅ compound.

In the invention described in claim 5, the intermediate layer is composed of two upper and lower layers, the lower (base side) intermediate layer is mainly composed of a Cu ₃ Sn compound, and the upper intermediate layer is mainly composed of a Cu ₆ Sn ₅ compound. The outermost layer is composed of two upper and lower layers, and the lower (substrate side) outermost layer is mainly composed of a Cu ₆ Sn ₅ compound, and the upper outermost layer is mainly composed of a Cu ₃ Sn compound. The plating material according to 1 or 2.

The invention described in claim 6 is the plating material according to claim 4 or 5, wherein an Sn phase or an Sn alloy phase is dispersed in the Cu ₆ Sn ₅ compound.

The invention described in claim 7 is a base layer made of any one of nickel, nickel alloy, cobalt, cobalt alloy, iron and iron alloy on a conductive substrate, and a copper-based layer made of copper or a copper alloy thereon. , thereon and the outermost layer is provided consisting of Cu-Sn intermetallic compound, the Cu-Sn intermetallic compound of the outermost layer is composed mainly of _Cu 6 Sn ₅ compound, Sn phase in the _Cu 6 Sn ₅ compound or The plating material is characterized in that the Sn alloy phase is dispersed.

According to the eighth aspect of the present invention, a base layer made of any one of nickel, nickel alloy, cobalt, cobalt alloy, iron and iron alloy is formed on a conductive substrate, and a Cu—Sn intermetallic compound is further formed thereon. the outer layer is provided, Cu-Sn intermetallic compound of said outermost layer is composed mainly of _Cu 6 Sn ₅ compound, Sn phase or Sn alloy phase in the _Cu 6 Sn ₅ compound, characterized in that the dispersed It is a plating material.

  The invention described in claim 9 is the plating material according to any one of claims 1 to 8, wherein at least two underlayers are provided on the conductive substrate.

  According to a tenth aspect of the present invention, there is provided an electric / electronic component characterized in that at least a sliding portion of the electric / electronic component is made of the plating material according to any one of the first to ninth aspects.

  An eleventh aspect of the present invention is an electrical / electronic component according to the tenth aspect, which is used for a fitting-type connector or a contact.

  Since the outermost layer is made of a hard Cu—Sn intermetallic compound, the fretting phenomenon is unlikely to occur even if the plating layer is thinned to reduce the contact pressure between terminals. Therefore, electrical / electronic parts such as terminals using the plating material of the present invention for the sliding portion can stably obtain good insertion / extraction and electrical connectivity.

In the plating material of the present invention, since the base layer made of Ni or the like is provided on the conductive base, the base component is prevented from diffusing into the outermost layer.
In the invention described in claim 1, since the copper-based layer made of Cu or the like, the intermediate layer made of Cu-Sn intermetallic compound layer, or the tin-based layer made of Sn or the like is provided on the underlayer, the invention is also claimed. In the invention described in 2, since an intermediate layer made of a Cu—Sn intermetallic compound layer and a tin-based layer made of Sn or the like are provided on the foundation layer, in the invention described in claim 7, the interlayer is formed on the foundation layer. Since the copper-based layer made of Cu or the like is provided, any of the underlayer components such as Ni is prevented from diffusing into the outermost layer. Therefore, good electrical connectivity can be obtained more stably.

  When the plating material of the present invention is produced by plating, for example, Ni, Cu (inner), Sn, Cu (outer) in this order on a substrate to form a plating laminate, and heat-treating the plating laminate In addition, the Cu (inner) layer and the Sn layer or only the Sn layer of the laminate are left, or the Sn phase or the Sn alloy phase is dispersed in the outermost layer or the intermediate layer of the plating material. The design of the laminate and the heat treatment of the plated laminate can be easily performed. Therefore, the plating material of the present invention is excellent in productivity.

As shown in FIG. 1 (a), the plating material 7 of the present invention has a base layer 2 made of Ni or the like on a conductive substrate 1, a copper-based layer 3 made of Cu or the like thereon, and a Cu-- An intermediate layer 4 made of an Sn intermetallic compound, a tin-based layer 5 made of Sn or the like thereon, and an outermost layer 6 made of a Cu—Sn intermetallic compound thereon (Claim 1), FIG. ), A base layer 2 made of Ni or the like, an intermediate layer 4 made of a Cu—Sn intermetallic compound thereon, a tin-based layer 5 made of Sn or the like thereon, and a conductive layer 1. The outermost layer 6 made of a Cu—Sn intermetallic compound is provided on the outermost layer or / and the intermediate layer made of a Cu—Sn intermetallic compound of the plating material according to claim 1 or 2. Sn phase or Sn alloy phase dispersed (Claim 6), as shown in FIG. As, on the conductive substrate 1, an underlayer 2 made of Ni, a copper-based layer 3 made of Cu is formed thereon, Sn phase or Sn alloy phase 9 mainly composed of Cu ₆ Sn ₅ compound thereon dispersion The outermost layer 6 made of the Cu—Sn intermetallic compound is provided (Claim 7), and as shown in FIG. 1 (d), the base layer 2 made of Ni, etc. And an outermost layer 6 made of a Cu—Sn intermetallic compound mainly composed of a Cu ₆ Sn ₅ compound and having a Sn phase or an Sn alloy phase 9 dispersed therein (Claim 8).

  The plating material according to the first aspect of the present invention is, for example, as shown in FIG. 2, on a conductive substrate 1, a Ni layer 2 ′, a Cu layer 3 ′, a Sn layer 4 ′, and a Cu layer 5 ′ are plated in this order. Then, the plated laminated body 8 is produced, and this is heat-treated to cause the Cu layer 3 ′ and the Sn layer 4 ′ to react with the Cu—Sn intermetallic compound layer (intermediate layer), and further, the Sn layer 4 ′ and the Cu layer. It is produced by reacting 5 ′ with a Cu—Sn intermetallic compound layer (outermost layer). During this reaction, thermal diffusion of the alloy components of the substrate is blocked by the Ni layer 2 '.

  In the invention described in claim 1, the volume ratio of the Cu layer 3 ′, the Sn layer 4 ′, and the Cu layer 5 ′ of the plating laminate 8 is the required thickness of the Cu—Sn intermetallic compound layer of the outermost layer 6 of the plating material 7. In consideration of the above, it is further determined that the copper-based layer 3 and the tin-based layer 5 are formed on the plating material 7 after the heat treatment. In the invention described in claim 2, the tin-based layer is determined to be formed. Since the thickness of the copper-based layer 3 and the tin-based layer 5 formed on the plating material 7 after the heat treatment does not need to be particularly strictly defined, the plating laminate 8 can be easily designed and heat-treated. Therefore, the plating material of the present invention is excellent in productivity.

  The thickness of the Cu layer (inner) 3 ′ of the plated laminate 8 is usually 0.01 μm or more. The upper limit is preferably about 5.0 μm in consideration of practical aspects, material costs, manufacturing costs, and the like. When the Cu layer (inner) 3 ′ is Cu, if the thickness is thin, the copper-based layer 3 of the plating material 7 after the heat treatment has many fine holes and the barrier function may be lost. The thickness of the Cu layer (inner) 3 ′ is made slightly thicker than that of the Cu alloy.

  In the present invention, since it takes a long time for the Cu layer (outer) 5 ′ to completely react with the Cu—Sn intermetallic compound by the heat treatment, Cu or Cu is formed on the surface of the outermost layer 6 of the plating material 7 after the heat treatment. Although some of the compound may remain, this hardly reduces the function of the plating material 7, so that the Cu or Cu alloy remains on the surface of the outermost layer 6 of the plating material 7. Material. The Cu or Cu compound is desirably removed using a chemical or the like.

  In the plating materials of the present invention described in claims 2 and 8, the copper-based layer 3 is not present on the base layer 2 of the plated material 7 after the heat treatment, but the copper-based layer 3 is not present. Thus, characteristics such as terminal insertion / extraction of the plating material are hardly deteriorated.

  In the present invention, a plating material including a terminal sliding portion whose outermost layer is a Cu-Sn intermetallic compound layer and a wire crimping portion whose outermost layer is a Sn layer is used as, for example, an automobile terminal. The plating material can produce a plating material in which the Sn layer is left on the outermost surface only in the wire crimping part by performing heat treatment after masking the Cu layer (outside) only at the portion to be the wire crimping part. . According to this method, it is possible to easily manufacture a plating material in which the material of the outermost layer is different for each part.

  When the heat treatment of the plating laminate 8 is performed by reflow treatment (continuous treatment), the actual temperature of the plating laminate is preferably 232 to 500 ° C. and is 0.1 second or longer and 10 minutes or shorter, more preferably 100 seconds or shorter, More preferably, it is heated for 10 seconds or less. This reflow treatment is realized, for example, by maintaining the temperature in the reflow furnace at 500 ° C. to 900 ° C. and heating for 10 minutes or less, preferably 100 seconds or less, more preferably 10 seconds or less. Actually, since the temperature in the reflow furnace is easier to measure than the temperature due to the actual temperature, it is desirable to perform the reflow process by managing the temperature in the reflow furnace. In addition, when performing heat processing by batch processing, the said plating laminated body 8 is preferably hold | maintained for several 10 minutes thru | or several hours in a 50-250 degreeC furnace. It should be noted that the temperature and heating time when heat treatment is performed by reflow treatment must be set to conditions suitable for the thickness of the plated laminate, etc., but as described in the examples described later, individual specific conditions are Can be set as appropriate.

  In the present invention, the conductive substrate 1 includes copper, phosphor bronze, brass, white, beryllium copper, Corson alloy and other copper-based materials, iron, Iron-based materials such as stainless steel, composite materials such as copper-coated iron materials and nickel-coated iron materials, and metal materials such as various nickel alloys and aluminum alloys are appropriately used.

  Of the various metal materials used for the conductive substrate 1, copper-based materials such as copper and copper alloys are particularly suitable because of their excellent balance between conductivity and mechanical strength. When the conductive substrate is other than a copper-based material, corrosion resistance and adhesion to the underlying plating layer are improved by covering the surface with copper or a copper alloy.

  The base layer 2 provided on the conductive substrate 1 is made of a metal such as Ni, Co, Fe or the like having a barrier function for preventing the components of the substrate 1 from thermally diffusing into the outermost layer 6, and Ni— having these as a main component. P, Ni—Sn, Co—P, Ni—Co, Ni—Co—P, Ni—Cu, Ni—Cr, Ni—Zn, Ni—Fe, and other alloys are preferred. Used. These metals and alloys have good plating processability and no problem in price. Among these, Ni and Ni alloys are recommended because the barrier function does not deteriorate even in a high temperature environment.

  Since the metal (alloy) such as Ni used for the underlayer 2 has a high melting point of 1000 ° C. or higher and the operating environment temperature of the connector is as low as 200 ° C. or less, the underlayer itself hardly causes thermal diffusion. The barrier function is effectively expressed. Depending on the material of the conductive substrate 1, the base layer 2 may have adhesion between the conductive substrate 1 and the copper-based layer 3 (the conductive substrate 1 and the intermediate layer 4 when the copper-based layer 3 is not present). There is also a function to enhance.

  When the thickness of the underlayer 2 is less than 0.05 μm, the barrier function is not fully exhibited, and when it exceeds 3 μm, the plating distortion increases and the base layer 1 is easily peeled off. Therefore, 0.05 to 3 μm is desirable. The upper limit of the thickness of the underlayer is preferably 1.5 μm, more preferably 0.5 μm, considering the terminal processability.

  In addition to Cu, a Cu alloy such as Cu—Sn can be applied to the Cu layer (inside and outside) of the plated laminate 8. The Cu concentration of the copper alloy is desirably 50% by mass or more.

When the Sn layer 4 'of the plating laminate 8 is Sn and the Cu layer (inner / outer) 3', and 5 'is Cu, the volume ratio of the Sn layer 4' and the Cu layer (inner + outer) (Sn layer / Cu Layer) is subjected to a predetermined heat treatment, whereby a base layer 2 is formed on the substrate 1, a copper-based layer 3 is formed thereon, and a Cu—Sn intermetallic compound layer (intermediate layer) is formed thereon. 4. A plating material 7 according to the invention described in claim 1 in which a tin-based layer 5 is formed thereon and a Cu—Sn intermetallic compound layer (outermost layer) 6 is formed thereon. By thinning or not providing the Cu layer (inner) 3 ′ of the plated laminate 8, the plating material 7 according to the invention described in claim 2 in which the copper-based layer 3 does not exist can be obtained.
The thickness of the Sn layer 4 ′ of the plated laminate 8 is preferably 0.038 to 4.0 μm, and the upper limit is more preferably 3.0 μm.

  The Ni layer 2 ′, Cu layers (inside and outside) 3 ′, 5 ′ and Sn layer 4 ′ of the plated laminate 8 can be formed by a PVD method or the like, but a wet plating method is preferable because it is simple and low cost.

In the present invention, examples of the outermost Cu—Sn intermetallic compound layer 6 include Cu ₆ Sn ₅ , Cu ₃ Sn, and Cu ₄ Sn. Cu ₆ Sn ₅ is produced by reacting 1.90 volumes of Sn with 1 volume of Cu. Cu ₃ Sn is produced by reacting 0.76 volume of Sn with 1 volume of Cu. Cu ₄ Sn is produced by reacting 0.57 volume of Sn with 1 volume of Cu.

Accordingly, when the plating laminate 8 having a volume ratio (Sn layer / Cu layer) of the Sn layer 4 ′ and the Cu layer (inside + outside) exceeds 1.90, for example, when the heat treatment is performed for a long time, the intermediate layer mainly composed of Cu ₆ Sn ₅ 4 or the outermost layer 6 is formed.
When the heat treatment time is short, Cu ₃ Sn or Cu ₄ Sn mainly composed of Cu ₃ Sn or Cu ₄ Sn is disposed at a position away from the Cu layer (inside and outside) 3 ′ and 5 ′ of the plated laminate 8. A compound is formed. Even with such a plating material (the invention described in claim 5), it is possible to obtain a terminal or the like that hardly causes fretting phenomenon.

In the present invention, the thickness of each layer in the case where the outermost Cu—Sn intermetallic compound layer 6 is composed of two layers of a Cu ₆ Sn ₅ layer and a Cu ₃ Sn layer (the invention described in claim 5) is not particularly defined. However, Cu ₆ Sn ₅ is desirably 0.01 to 5.0 μm, and Cu ₃ Sn is desirably 0.008 to 4.0 μm. The same applies to the intermediate layer (Cu—Sn intermetallic compound layer).

  When the volume ratio of the Sn layer 4 ′ of the plating laminate 8 is large and the heat treatment is performed on the high temperature side or the long time side, the Sn or Sn forming the Sn layer 4 ′ of the plating laminate 8 is formed. In the alloy, the Sn phase or the Sn alloy phase (9) may be dispersed in the intermediate layer 4 or the outermost layer 6. In this case as well, there is no difference from the other embodiments in that a terminal that is less likely to cause fretting phenomenon can be obtained, and that the plated laminate 8 can be easily designed and heat-treated.

In the present invention, the Cu—Sn intermetallic compound of the intermediate layer 4 or the outermost layer 6 in which the Sn phase or the Sn alloy phase (9) is dispersed is usually mainly a Cu ₆ Sn ₅ compound.

In the present invention, the effect of preventing the fretting phenomenon by the Cu—Sn intermetallic compound (Cu ₆ Sn ₅ ) in the outermost layer 6 can be obtained satisfactorily regardless of the presence or absence of the Sn phase or the Sn alloy phase (9).

  In the present invention, a plating layer made of a different material thinner than the adjacent layers may be interposed between the layers of the plating material 7 (including the conductive substrate and the base layer). Moreover, the shape of the plating material 7 is arbitrary, such as a strip, a round line, and a square line.

[Example 1]
Degreasing and pickling are performed in this order on a copper alloy strip (brass) having a thickness of 0.25 mm, and then Ni, Cu, Sn, and Cu are electroplated in this order on the copper alloy strip in order to produce a plated laminate. Next, the plating laminate 8 was subjected to a heat treatment by a reflow processing method to produce a plating material 7 having the structure shown in FIG. The heat treatment conditions were such that the temperature in the reflow furnace was 740 ° C. and the actual temperature of the sample was 285 ° C. The thickness of the Ni layer 2 ′ of the plated laminate 8 was 0.4 μm, and the thickness (volume) of the Cu layer (inner) 3 ′, Sn layer 4 ′, and Cu layer (outer) 5 ′ was variously changed. The thickness (volume) ratio (Sn layer / Cu layer) of the Sn layer 4 ′ and the Cu layer (inside + outside) was variously changed in the range of 1.95 to 2.20.
Table 1 shows the plating conditions for each metal.

  About each obtained plating material, the following fine sliding test was done to the frequency | count of sliding reciprocation 1000 times, and the change of the contact resistance value was measured continuously.

The fine sliding test was performed as follows.
That is, as shown in FIG. 3, two plating materials 11 and 12 are prepared, and after each degreasing and cleaning, a hemispherical overhanging portion (the outer surface of the convex portion is the outermost surface) having a radius of curvature of 1.05 mm provided on the plating material 11 The outermost layer surface 12a of the plating material 12 is brought into contact with the layer surface 11a at a contact pressure of 3N, and in this state, both are reciprocated at a sliding distance of 30 μm in an environment of a temperature of 20 ° C. and a humidity of 65%. An open-circuit voltage of 20 mV was applied between the plating materials 11 and 12, a constant current of 5 mA was applied, and the voltage drop during sliding was measured by the four-terminal method to determine the change in electrical resistance every second. The frequency of reciprocating motion was about 3.3 Hz. Table 2 shows the contact resistance value before the fine sliding test and the maximum contact resistance value during the fine sliding test.

About each plating material 7, (1) The thickness of the Cu-Sn intermetallic compound layer of the outermost layer 6 and the intermediate | middle layer 4, and the thickness of the tin-type layer 5 were measured by the anodic dissolution method using R50 solution made from a Cocourt company. . (2) The thickness of Cu remaining on the surfaces of the copper-based layer 3 and the outermost layer 6 was measured by an anodic dissolution method using a solution of R52 manufactured by Kocourt. (3) The thickness of the underlayer (Ni layer) 2 was measured using a fluorescent X-ray film thickness meter. The measurement area was 1 cm ² for all. The measurement results for each thickness are also shown in Table 2.

[Example 2]
A plating material 7 having the structure shown in FIG. 1 (a) or (b) was manufactured by the same method as in Example 1 except that the heat treatment was performed by a batch processing method, and the same tests and investigations as in Example 1 were performed.

[Comparative Example 1]
A plating material was produced by the same method as in Example 1 or 2, except that the volume ratio (Sn layer / Cu layer) of the Sn layer and the Cu layer (inside + outside) of the plating laminate was 1.90. The same test and investigation as in No. 1 were conducted.

[Comparative Example 2]
A plating material was produced by the same method as in Example 1 or 2, except that the volume ratio (Sn layer / Cu layer) of the Sn layer and the Cu layer (inside + outside) of the plating laminate was 1.80. The same test and investigation as in No. 1 were conducted.

[Comparative Example 3]
The same test and investigation as in Example 1 were performed on a plating material obtained by electroplating a Ni underlayer and an Sn outermost layer in this order on a copper alloy substrate. The thickness of Sn was changed in two ways.

  The investigation results of Examples 1 and 2 and Comparative Examples 1 to 3 are shown in Table 2. In addition, the heat treatment conditions in Table 2 describe the actual temperature of the sample.

  As is apparent from Table 2, the plating materials 7 of Examples of the present invention (Examples 1 and 2) all had a low maximum contact resistance value during the fine sliding test. This is because the plating material 7 of the present invention has an outermost layer 6 made of a hard Cu—Sn intermetallic compound, so that the fretting phenomenon hardly occurs, and the tin-based layer 5 and the intermediate layer 4 exist below the outermost layer 6. This is because the thermal diffusion of the base component such as Ni is prevented, and further, the thermal diffusion of the component of the substrate 1 is prevented by the base layer 2, and the outermost layer 6 is not contaminated and its function is well maintained.

  In contrast, Comparative Example 1 was difficult to manufacture because neither a copper-based layer nor a tin-based layer was present. In Comparative Example 2, the volume ratio is 1.80, so that the Cu layer remains on the outermost layer surface. In Comparative Example 3, the outermost layer is a Sn layer, and thus fretting phenomenon occurs. Increased.

  When the contact resistance exceeds 10 mΩ in the fine sliding test, it is considered difficult to use for automobile terminals, but the plating materials 7 (Examples 1 and 2) of the present invention are significantly below 10 mΩ. It can be used as a car terminal.

[Example 3]
Example No. 1 in Example 1 except that the underlayer 2 was provided in two layers, a Ni layer (0.2 μm) and a Ni—Co—P alloy layer (0.2 μm). A plating material was produced by the same method as in Example 1, and a fine sliding test was conducted by the same method as in Example 1. As a result, the initial value of the contact resistance was 1.7 mΩ, and the maximum value during the micro-sliding test was 3.2 mΩ, both showing extremely low values. This is because the diffusion of the components of the substrate 1 is more reliably prevented during the heat treatment and during use.

[Example 4]
Other than shortening the heat treatment time of the plated laminate 8 (heat treatment time: 12 h) A plating material 7 was produced by the same method as in Example 4, and a fine sliding test was conducted by the same method as in Example 1. In this plating material 7, the lower side (base side) of the intermediate layer 4 is mainly composed of Cu ₃ Sn compound, the upper side is mainly composed of Cu ₆ Sn ₅ compound, and the lower side (base side) of the outermost layer 6 is Cu ₆ Sn. _Although the plating material was mainly composed of ₅ compounds and the upper side was mainly composed of Cu ₃ Sn compound, the contact resistance had an initial value of 2.1 mΩ and a maximum value of 4.6 mΩ in the micro-sliding test. The entire layer 4 and outermost layer 6 exhibited a low contact resistance value equivalent to the plating material (No. 4 in Example 2) mainly composed of Cu ₆ Sn ₅ compound.

[Example 5]
No. of Example 1 No. 3 plating laminate 8 and reflow treatment in Example 1 No. The plating material 7 was manufactured by the same method as Example 1 except having performed at the temperature higher than the case of 3 (temperature in a reflow furnace: 770 degreeC).
The obtained plating material 7 has substantially the same structure as that shown in FIG. 1A, but the thickness of the tin-based layer 5 is reduced, and the outermost layer 6 and the intermediate layer 4 are mainly composed of Cu ₆ Sn ₅ . The Sn phase or the Sn alloy phase 9 was dispersed in the Cu—Sn intermetallic compound to have an intermediate structure between FIG. 1 (A) and FIG. 1 (C).
This plating material 7 was subjected to the same sliding test as in Example 1, and the change in the contact resistance value was continuously measured. As a result, the contact resistance had an initial value of 1.8 mΩ and a maximum value of 3.6 mΩ. It was equivalent to the result of 3.

[Example 6]
No. 2 in Example 2. No. 6 was used for heat treatment in Example 2 No. A plating material was produced by the same method as in Example 1 except that it was performed at a temperature higher than the case of 6 (substance temperature of the sample: 180 ° C.).
The obtained plating material has substantially the same structure as that shown in FIG. 1B, but the thickness of the tin-based layer 5 is reduced, and the outermost layer 6 and the intermediate layer 4 are mainly composed of Cu ₆ Sn _5. The Sn phase or the Sn alloy phase 9 was dispersed in the Cu—Sn intermetallic compound to be formed, and had an intermediate configuration between FIG. 1 (B) and FIG. 1 (C).
This plating material 7 was subjected to the same sliding test as in Example 1, and the change in the contact resistance value was continuously measured. As a result, the contact resistance had an initial value of 1.8 mΩ and a maximum value of 3.8 mΩ. It was equivalent to the result of 3.

[Example 7]
A copper alloy strip (brass) having a thickness of 0.25 mm is subjected to degreasing and pickling in this order, and then the copper alloy strip is electroplated with Ni, Cu, Sn, and Cu in this order in the order of layers as shown in Table 1. The laminated body 8 was produced, and then the plated laminated body 8 was subjected to a heat treatment by the reflow treatment method under the same conditions as in Example 5 to produce a plating material 7. The same tests and investigations as in Example 1 were performed. Here, the thickness of the Ni layer 2 ′ of the plated laminate 8 is 0.4 μm, and the thickness (volume) ratio (inner / outer) of the Cu layer (inner) 3 ′ and the Cu layer (outer) 5 ′ is 3.0. The thickness (volume) ratio (Sn layer / Cu layer) of the Sn layer 4 ′ and the Cu layer (inside + outside) was 2.60. The thickness of the Sn layer 4 ′ was 1.0 μm.

The obtained plating material 7 has a structure as shown in FIG. 1 (c), in which the copper-based layer 3 is formed on the base layer 2, and the outermost layer 6 is formed thereon. The outermost layer 6 is made of Cu. _The Sn phase or Sn alloy phase 9 was dispersed in a Cu—Sn intermetallic compound mainly composed of ₆ Sn ₅ .
This plating material 7 was subjected to the same sliding test as in Example 1, and the change in the contact resistance value was continuously measured. As a result, the contact resistance had an initial value of 1.8 mΩ and a maximum value of 3.9 mΩ. It was equivalent to the result of 3.

[Example 8]
In Example 7, the thickness (volume) ratio (inner / outer) of the Cu layer (inner) 3 ′ and the Cu layer (outer) 5 ′ is 1.0, and the thickness of the Sn layer and Cu layer (inner + outer) ( A plating material 7 was produced by the same method as in Example 7 except that the volume ratio (Sn layer / Cu layer) was 2.60, and the same tests and investigations as in Example 7 were performed.

The resulting plated material 7 is configuration as shown in FIG. 1 (d), which outermost layer 6 is formed on the underlying layer 2, the outermost layer 6 is mainly composed of Cu ₆ Sn ₅ Cu- The Sn phase or the Sn alloy phase 9 was dispersed in the Sn intermetallic compound. This plating material had an initial value of 1.9 mΩ and a maximum value of 4.0 mΩ as the contact resistance. It was equivalent to the result of 3.

  From the test results of Examples 5 to 8, the contact resistance value is low even in the plating material 7 in which the Sn phase or the Sn alloy phase 9 is dispersed in the intermediate layer 4 and the outermost layer 6 or the Cu—Sn intermetallic compound of the outermost layer 6. It turns out that it is obtained. This plating material 7 is obtained by dispersing the Sn phase and the Sn alloy phase 9 in the intermediate layer 4 or the outermost layer 6. As in Examples 1 to 4, the plating laminate 8 can be easily designed and heat-treated. Excellent in properties.

  When the fitting type connector terminal is manufactured using the plating material 7 obtained in Examples 1 to 8 and put into practical use in the engine room of an automobile, good insertion / extraction properties can be stably obtained over a long period of time. It was confirmed that

(A)-(d) is a perspective explanatory drawing which shows an example of embodiment of the plating material of this invention. It is a perspective explanatory view showing an embodiment of a plating layered product used for manufacture of a plating material of the present invention. It is a perspective explanatory view of a fine sliding test method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Conductive substrate 2 Base layer made of Ni or the like 3 Copper-based layer made of Cu or Cu alloy 4 Intermediate layer made of Cu-Sn intermetallic compound 5 Tin-based layer made of Sn or Sn alloy 6 From Cu-Sn intermetallic compound Outermost layer 7 plating material 2 ′ Ni layer 3 ′ Cu layer (inner)
4 'Sn layer 5' Cu layer (outside)
8 Plating laminate 9 Sn phase or Sn alloy phase 11 Plating material 11a Hemispherical overhang 12 provided on plating material Plating material 12a Outermost layer surface of plating material

Claims (11)

  A base layer made of any one of nickel, nickel alloy, cobalt, cobalt alloy, iron, and iron alloy on a conductive substrate, a copper-based layer made of copper or a copper alloy thereon, and a Cu-Sn metal space between them A plating material comprising: an intermediate layer made of a compound; a tin-based layer made of tin or a tin alloy; and an outermost layer made of a Cu—Sn intermetallic compound.   An underlayer made of nickel, nickel alloy, cobalt, cobalt alloy, iron or iron alloy on a conductive substrate, an intermediate layer made of Cu-Sn intermetallic compound thereon, and tin or a tin alloy thereon A plating material, comprising: a tin-based layer comprising: an outermost layer comprising a Cu—Sn intermetallic compound; Plating material according to claim 1 or 2, wherein the intermediate layer and the outermost layer of the Cu-Sn intermetallic compound is characterized by mainly comprising Cu 3 _Sn compound. The plating material according to claim 1, wherein the Cu—Sn intermetallic compound of the intermediate layer and the outermost layer is mainly composed of a Cu ₆ Sn ₅ compound. The intermediate layer is composed of two upper and lower layers, the lower (substrate side) intermediate layer is mainly composed of Cu ₃ Sn compound, the upper intermediate layer is mainly composed of Cu ₆ Sn ₅ compound, and the outermost layer is composed of upper and lower layers. The plating material according to claim 1, wherein the outermost layer on the lower side (substrate side) is mainly composed of a Cu ₆ Sn ₅ compound, and the uppermost outermost layer is mainly composed of a Cu ₃ Sn compound. The plating material according to claim 4 or 5, wherein an Sn phase or an Sn alloy phase is dispersed in the Cu ₆ Sn ₅ compound. A base layer made of any one of nickel, nickel alloy, cobalt, cobalt alloy, iron, and iron alloy on a conductive substrate, a copper-based layer made of copper or a copper alloy thereon, and a Cu-Sn metal space between them and the outermost layer is provided made of a compound, the Cu-Sn intermetallic compound of said outermost layer is composed mainly of _Cu 6 Sn ₅ compound, Sn phase or Sn alloy phase in the _Cu 6 Sn ₅ compound is dispersed Plating material characterized by A base layer made of any one of nickel, nickel alloy, cobalt, cobalt alloy, iron, and iron alloy is provided on the conductive substrate, and an outermost layer made of Cu-Sn intermetallic compound is provided on the base layer. plating material Cu-Sn intermetallic compound layer is mainly composed of _Cu 6 Sn ₅ compound, Sn phase or Sn alloy phase in the _Cu 6 Sn ₅ compound, characterized in that the dispersed.   The plating material according to claim 1, wherein at least two underlayers are provided on the conductive substrate.   An electrical / electronic component, wherein at least a sliding portion of the electrical / electronic component is made of the plating material according to claim 1.   The electric / electronic component according to claim 10, wherein the electric / electronic component is used for a fitting-type connector or a contact.

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