JP2022057398A - Plated product - Google Patents

Abstract

To provide a plated product in which the thickness of a plated layer for obtaining a suitable plated layer, specifically, the thickness of a first plated layer appropriate when a platinum group metal or an alloy thereof is used for a second plated layer, is prescribed while using a correlation between the difference in lattice constants and the thickness of the plated layers.SOLUTION: A plated product comprises: a conductive substrate; a first plated layer having the thickness of about 1.0 to about 4.0 μm, which is laminated on one surface of the substrate; and a second plated layer composed of a platinum group metal or an alloy thereof, which is laminated on the other surface of the substrate that is on the opposite side to the first plated layer in the thickness direction of the first plated layer. The difference between the lattice constant of the substrate and the lattice constant of the first plated layer is 15% or less. The difference between the lattice constant of the first plated layer and the lattice constant of the second plated layer is also 15% or less.SELECTED DRAWING: Figure 1

Description

The present invention relates to a plated product, particularly a plated product having an electroplated plating layer.

From the functional point of view, the plating layer formed by electroplating generally includes at least two, a first plating layer as a base layer and a second plating layer as a finishing layer provided on the base layer. Through many years of experience, the inventors of the present application have found that if the thickness of the first plating layer is too large, the second plating layer is likely to break during precipitation, and if the thickness of the first plating layer is too small. On the other hand, when the thickness of the first plating layer is within a predetermined range, the size of the first plating layer depends on the material of the second plating layer. It was discovered that an appropriate plating layer can be obtained without breaking or pinholes, although the amount varies.

In addition to the above findings, the present inventors have further described in Non-Patent Document 1, that is, in order to properly perform electroplating, for example, between the substrate as the base material and the first plating layer, or the first. Based on the theory that attention should be paid to the consistency of the lattice constants between the 1st plating layer and the 2nd plating layer, and more specifically, the difference in the lattice constants (which can also be regarded as the difference in the interatomic distance). As a result of intensive research while paying attention to the relationship between the difference between the two and the thickness of the first plating layer, the former problem, that is, when the thickness of the first plating layer is too large, the second plating occurs at the time of precipitation. The reason why the layer is broken is that the difference in lattice constant between the first plating layer and the second plating layer is large, so that the second plating layer is pulled by the first plating layer and the second plating is performed. It was inferred that this was due to the interatomic distance of the layer becoming larger than the permissible range and the interatomic bond breaking, and further research was conducted based on this inference, and the difference in lattice constant and the plating layer We found that there was a correlation with the thickness of.

T. Seiyama, DENKI KAGAKU 38 (1970) 707-713

The present invention utilizes the correlation between the difference in lattice constant and the thickness of the plating layer, and the thickness of the plating layer for obtaining an appropriate plating layer, especially the platinum group metal or a platinum group metal thereof as the second plating layer. It is an object of the present invention to provide a plated product in which the thickness of the first plating layer required to obtain an appropriate first plating layer when an alloy is used is specified.

In order to solve the above problems, the plated product according to one aspect of the present invention is a first plating having a thickness of about 1.0 to about 4.0 μm laminated on a conductive substrate and the surface of the substrate. The layer and one surface on which the substrate is provided are made of a platinum group metal or an alloy thereof laminated on the other surface of the first plating layer located on the opposite side in the thickness direction of the first plating layer. A second plating layer is provided, and the difference between the lattice constants of the substrate and the lattice constants of the first plating layer, and the difference between the lattice constants of the first plating layer and the lattice constants of the second plating layer are, respectively. It is characterized by being 15% or less.

According to the present invention, there is provided a plated product in which the thickness of the first plating layer required to obtain an appropriate first plating layer when a platinum group metal or an alloy thereof is used for the second plating layer is specified. Can be done.
It is sufficient that the plated product includes only the first plating layer as the base layer and the second plating layer as the finishing layer provided on the base layer, not only from the functional viewpoint but also from the structural viewpoint. Therefore, according to the present invention, an additional effect such that a plated product having only two plating layers can be provided can be obtained. The plating layer of the plating product on the market today is considered to be three or more layers, and as far as the applicant of the present application knows, there is no plating product having only two plating layers. In the conventional product, in order to improve the performance such as corrosion resistance, it is considered necessary to have three or more plating layers or to provide a protective layer on the outermost plating layer. However, these conventional solutions are not preferable in terms of increasing the material and manufacturing cost and also from the viewpoint of matching the lattice constants. On the other hand, according to this configuration, a plated product having sufficient performance can be obtained even if the number of plating layers is only two.

It is a schematic cross-sectional view near the surface of a terminal fitting. It is a reference figure which showed the lattice constant of a copper alloy in relation to the dissolution concentration of an additive. It is a figure which showed the shape of a terminal member. It is a figure which showed the evaluation method roughly. It is a photograph which shows an example of each state of the evaluation result. It is the schematic sectional drawing of the modification which made the 1st plating layer into a plurality of layers.

A preferred embodiment of the plated product according to the present invention will be described. Here, the terminal metal fittings which are interface connectors used in electronic devices such as smartphones and computers will be described as an example, but of course, the present invention is not intended to be limited thereto. The terminal fitting includes, for example, a signal terminal of a connector and a power supply terminal. Although the terminal fittings are illustrated, the plated product of the present invention includes metal parts used in electronic devices such as terminal fittings, as well as home appliances such as refrigerators and washing machines, for which IoT technology is expected to be applied. Etc., All plated products applied to metal parts that require corrosion resistance, etc. are included.

1. 1. Overall Configuration FIG. 1 shows a schematic cross-sectional view near the surface of the terminal fitting 1. The cross section of the terminal fitting 1 includes at least a substrate 10 which is a base metal, a first plating layer 11 as a base layer, and a second plating layer 12 as a finishing layer in the vicinity of the surface thereof.

<Hypokeimenon>
The substrate 10 is a main body of the terminal fitting 1 to be plated, that is, a member constituting the terminal member 1a, and is conductive suitable for performing electrodeposition, more specifically, a wet electroplating method. It is made of members. Examples of the conductive material suitable for use include copper or a copper alloy, or aluminum or an aluminum alloy. Generally, commonly used iron or iron alloy is not always suitable as compared with copper or the like. When iron or an iron alloy is used, the first plating layer is determined in relation to forming the second plating layer 12 with a platinum group metal or an alloy thereof, and further, in relation to the second plating layer 12. In relation to the lattice constant of 11 and the lattice constant of the second plating layer 12 determined by the relationship with the first plating layer 11, between the substrate 11 and the second plating layer 12, and between the second plating layer 12 and the second plating layer 12. This is because it is considered that a misfit is likely to occur between the plating layer 11 and the plating layer 11. The copper alloy or aluminum alloy suitable for use is also determined from the viewpoint of misfit, taking into consideration the difference from the lattice constants of the first plating layer and the second plating layer. As will be described later, for example, as the copper alloy, phosphor bronze (Cu—Sn—P system), Corson copper (Cu—Ni—Si system), beryllium copper (Cu—Be system), brass (Cu—Zn system) Can be used. The thickness of the substrate is not particularly limited, but it is preferably a thickness sufficient to support the first plating layer and the second plating layer.

<First plating layer>
The first plating layer 11 is laminated (plated) on the surface 10a of the substrate 10. It is preferably laminated directly on the surface 10a of the substrate 10. This is because the correlation between the difference in lattice constant and the thickness of the plating layer can be easily adjusted by directly laminating. It is possible to interpose another thin layer between the first plating layer 11 and the substrate 10 without directly laminating, but in this case, the difference in lattice constant between the first plating layer 11 and the substrate 10 is substantially the same. It shall not affect the target. The first plating layer 11 is formed of a member suitable for carrying out a wet electroplating method, and examples of the material suitable for use include nickel or an alloy thereof. Cobalt or cobalt alloys that are commonly used are not always suitable as compared with nickel and the like. When cobalt or a cobalt alloy is used, the second plating layer 12 is formed of a platinum group metal or an alloy thereof, and more specifically, in relation to the lattice constant of the second plating product 12. This is because it is considered that a misfit is likely to occur between the first plating layer 11 and the second plating layer 12. The nickel alloy suitable for use is also determined from the viewpoint of misfit, taking into consideration the difference from the lattice constant of the second plating layer. The thickness of the first plating layer 11 is about 1.0 to about 4.0 μm in order to obtain an appropriate plating layer for corrosion resistance while utilizing the correlation between the difference in lattice constant and the thickness of the plating layer. It is necessary that the thickness is about 1.25 to about 3.75 μm, more preferably about 1.50 to about 2.5 μm. The word "about" is added in consideration of the performance required for the plated product and the possibility of slight fluctuations and errors during plating.

<Second plating layer>
The second plating layer 12 is laminated on the other surface 12b of the first plating layer 11 located on the opposite side of the thickness direction "t" of the first plating layer 11 from the one surface 12a on which the substrate 10 is provided. .. The second plating layer 12 is preferably directly laminated (plated) on the other surface 12b of the first plating layer 11. This is because the correlation between the difference in lattice constant and the thickness of the plating layer can be easily adjusted by directly laminating. It is also possible to interpose another thin layer between the second plating layer 12 and the first plating layer 11 without directly laminating, but in this case, the second plating layer 12 and the first plating layer 11 It shall not substantially affect the difference in lattice constant. The second plating layer 12 is made of a member suitable for performing a wet electroplating method, and is a layer arranged on the outermost surface of the terminal fitting 1, so that the connection reliability is low with low contact resistance. It is preferable that the material has high properties. In the present embodiment, a platinum group metal or an alloy thereof is used, but other materials can be used in consideration of the correlation between the difference in lattice constant and the thickness of the plating layer. Platinum group metals include platinum (Pt), palladium (Pd), rhodium (Ph), ruthenium (Ru), iridium (Ir), and osmium (Os). From the viewpoint of, platinum or rhodium is preferable. In the past, rhodium was generally used because rhodium was cheaper than platinum, but in recent years, the price of rhodium has soared, and platinum and rhodium have different corrosion resistance. Since there is no difference in the general mixed gas test between them, and platinum shows better results than rhodium in the performance evaluation method used in the present invention, in the present embodiment, it is not rhodium. We decided to use platinum. The reason why platinum shows better results is that platinum (Pt) has a higher ability to maintain an oxide film than rhodium (Rh), in other words, it has a high corrosion resistance due to having a dense oxide film. It can be mentioned that it can be demonstrated. This point will be described in more detail below.
Platinum (Pt) and rhodium (Rh) in salt water electrolysis compete with insoluble oxides for the formation of soluble chlorides, and platinum (Pt) has a higher ability to maintain oxides. The reason for this is considered to be the denseness of the oxide. Compare the volume of the metal to the volume when the metal becomes an oxide (Kubashevsky's volume fraction), and if this value is greater than 1, the oxide layer formed is the surface of the underlying metal. It is thought that it covers the surface closely and exhibits excellent corrosion resistance. (Such oxides are generally called passivation films.) When arranged from the one with the smallest volume fraction, the order is PtO (1.65) <Rh2O3 (1.87) <PtO2 (2.45), and PtO2 is the most precise. It can be expected to be an oxide film. In addition, the influence of the production rate can be considered. The rate of metal salt formation differs depending on the metal ion, and the order is reported to be Pt (II) ≫ Rh (III) ≫ Pt (IV). This means that chloride formation from PtO2 is the slowest.

The platinum and rhodium alloys suitable for use are also determined from the viewpoint of misfit, taking into consideration the difference from the lattice constant of the first plated product 11. The thickness of the second plating layer needs to be about 0.1 μm or more in order to obtain an appropriate plating layer for corrosion resistance while utilizing the correlation between the difference in lattice constant and the thickness of the plating layer. Yes, preferably 0.2 μm or more, more preferably 0.4 μm or more. From a performance point of view, there is no substantial problem even if it is made thicker. However, from the viewpoint of cost, it is preferably about 1.0 μm or less. The reason for adding the word "about" is as described above.

<Lattice constant>
As is clear from the description of Non-Patent Document 1, from the viewpoint of preventing misfitting, the difference between the lattice constant of the substrate 10 and the lattice constant of the first plating layer 11, and the lattice constant of the first plating layer 11 and the second The difference in the lattice constants of the plating layers 12 is set to 15% or less, respectively.

(Lattice constant of the substrate)
For example, the lattice constant of copper, which is an example of a substrate material, is about 3.62 Å. FIG. 2 is a reference diagram showing the lattice constant of the copper alloy in relation to the dissolution concentration of the additive. The horizontal axis shows the dissolution concentration (% by weight) of the additive in the alloy, and the vertical axis shows the lattice constant (Å) of the copper alloy. In copper alloys, in general, increasing the dissolution concentration of additives (excluding Ni) tends to increase the lattice constant, while increasing the dissolution concentration of Ni tends to gradually decrease the lattice constant. .. Copper alloys often used for the terminal fitting 1 include phosphor bronze (Cu-Sn-P series), Corson copper (Cu-Ni-Si series), beryllium copper (Cu-Be series), and brass (Cu-) described above. Zn system) can be mentioned. The lattice constants of these alloys are almost the same as those of copper.
For example, even in the case of phosphor bronze having the largest increasing tendency, the addition ratio of tin (Sn) that increases the lattice constant is usually 11% or less by weight, and phosphorus (P) is usually 0.35% by weight or less, which is ignored. The lattice constant is about 3.73 Å, to the extent that it can be done. Further, in Corson copper, the addition ratio of nickel (Ni) that gradually decreases the lattice constant is usually 1 to 5% by weight, and silicon (Si) that gradually increases the lattice constant is usually 1.00% by weight or less. The lattice constant is about 3.62 Å, as it is negligible. Further, in beryllium copper (Cu-Be system), the addition ratio of beryllium (Be) that increases the lattice constant is usually 1% by weight or less, and in addition, nickel (Ni) that gradually reduces the lattice constant is usually 11% by weight. Since it is less than%, the lattice constant is within about 3.60 to 3.62 Å. Furthermore, brass (Cu—Zn-based) is an alloy containing a large amount of additives other than copper, but zinc (Zn), which slowly increases the lattice constant, is added in an amount of 30% or less, so that the lattice constant is high. , About 3.68 Å.

(Lattice constant of the first plating layer and the second plating layer)
The lattice constant of nickel (Ni), which is an example of the first plating layer, is about 3.524 Å, and the lattice constant of platinum (Pt), which is an example of the second plating layer, is about 3.924 Å. Since the lattice constants of these alloys can be considered in the same manner as copper alloys, detailed description thereof will be omitted here.

As is clear from the above description, when the above materials are used, the difference between the lattice constant of the substrate 10 and the lattice constant of the first plating layer 11, and the lattice constant of the first plating layer 11 and the second plating layer 12 The difference in lattice constant can be set to 15% or less, respectively, and thus misfit can be prevented.

<Plating method>
A general manufacturing method well known to those skilled in the art, as disclosed in Japanese Patent No. 6533652, can be used.
First, the main body of the terminal fitting 1, that is, the terminal member 1a is prepared. The terminal member 1a is formed by punching from a metal plate of a conductive material by a press. FIG. 3 shows the shape of the terminal member 1a (terminal fitting 1). A total of six strip pieces 20a to 20f, which are finally used as terminals, are provided on the tip end side of the terminal member 1a. The strip pieces 20a to 20f are connected by a carrier portion 30 for holding and transporting them on the rear end side thereof. A plurality of guide holes 40 used for transporting the terminal member 1a are formed in the carrier portion 30.

The plating treatment mainly includes a pretreatment, a plating treatment of the first plating layer 11 as a base layer, a plating treatment of the second plating layer 12 as a finishing layer, and a post-treatment in this order. From the viewpoint of productivity and cost, it is preferable that these processing steps are continuously performed by a hoop plating (reel-to-reel plating) method / apparatus.

First, as pretreatment, alkaline degreasing for removing oil on the surface, pickling for removing the oxide film on the surface, and water washing for removing chemicals and the like are performed. The pretreatment is generally performed in the order of water washing, alkaline degreasing, water washing, pickling, and water washing.

In the plating treatment of the first plating layer 11 and the plating treatment of the second plating layer 12, the terminal member 1a wound on one reel is wound on the other empty reel, and the terminal member 1a is cathodeed in the target plating tank. In addition, the plating solution is used as an anode.

In order to plate the first plating layer 11, for example, a base plating tank is filled with a plating solution of nickel or an alloy thereof, and a pair of electrodes are immersed to serve as an anode. The tip portion 20 of the terminal member 1a is continuously moved between the electrodes so as to be immersed in the base plating solution. Negative electrode rollers are provided in front of and behind the base plating tank (moving directions of the strip pieces 20a to 20f of the terminal member 1a) so that the terminal member 1a serves as a cathode, so as to sandwich both plate surfaces of the carrier. Contact. As a result, nickel (Ni), which is the first plating layer 11, is applied to each of the strip pieces 20a to 20f.

After the first plating layer 11 is plated, the strip pieces 20a to 20f are immersed in a finishing plating tank, and platinum (Pt) is plated as the second plating layer 12 in the same manner as the first plating layer 11. .. Further, gold (Ag) plating may be applied as the outermost surface plating.

The first and second plating layers 11 and 12 formed by the plating solution of the present invention can have a desired thickness by adjusting the carrier moving speed, the electrolysis time, the electrolysis current and the like. As a post-treatment, the tip portion 20 of the terminal member 1a after plating is washed with water and then dried with hot air.

2. 2. Example <Example 1>
The plated terminal fitting 1 was manufactured by the general manufacturing method described above.
First, a copper plate having a thickness of 0.12 mm was punched out to prepare a terminal member 1a having the shape shown in FIG. The width of the strip pieces 20b to 20e located in the center is 0.25 mm, the width of the strip pieces 20a and 20f located at both ends is 0.29 mm, and the pitch between the strip pieces is 0.5 mm. The length of the portion of the strip protruding from the carrier 30 was set to 3.5 mm.

Next, as pretreatment, alkaline degreasing for removing oil on the surface, pickling for removing the oxide film on the surface, and water washing for removing chemicals and the like were performed. The pretreatment was performed in the order of water washing, alkaline degreasing, water washing, pickling, and water washing.

In the plating treatment of the first plating layer 11 and the plating treatment of the second plating layer 12, the terminal member 1a wound on one reel is wound on the other empty reel, and the terminal member 1a is cathodeed in the target plating tank. This was done by using a plating solution as an anode.

In order to plate the first plating layer 11, the base plating tank was filled with a nickel plating solution, and a pair of electrodes were immersed in the base plating tank to serve as an anode. The strip pieces 20a to 20f provided on the tip end side of the terminal member 1a were continuously moved between the electrodes so as to be immersed in the base plating solution. Negative electrode rollers are provided in front of and behind the base plating tank (moving directions of the strip pieces 20a to 20f of the terminal member 1a) so that the terminal member 1a serves as a cathode, and contacts are provided so as to sandwich both plate surfaces of the carrier 30. I let you. As a result, nickel (Ni), which is the first plating layer 11, was applied to the tip portion 20 of the terminal member 1a.

After the first plating layer 11 is plated, the strip pieces 20a to 20f are immersed in a plating tank filled with a platinum plating solution to form platinum (Pt) as the second plating layer 12 in the same manner as the first plating layer 11. ) Was plated.

The thicknesses of the first and second plating layers 11 and 12 formed by the plating solution of the present invention were adjusted by appropriately adjusting the moving speed of the carrier, the electrolytic time, the electrolytic current and the like. More specifically, the thickness of the first plating layer 11 is fixed at 2.00 μm, while the thickness of the second plating layer 12 is adjusted stepwise in the range of 0.1 to 1.0 μm. Multiple plated products were obtained. Then, as a post-treatment, the strip pieces 20a to 20f were washed with water and then dried with hot air.

<Examples 2 to 13>
A plurality of plated products were obtained in the same manner as in Example 1.
More specifically, in the respective embodiments 2 to 13, the thickness of the first plating layer 11 is fixed to any value in the range of 1.25 to 4.00, while the respective embodiments 2 to 3. In No. 13, the thickness of the second plating layer 12 was adjusted stepwise in the range of 0.1 to 1.0 μm to obtain a plurality of plated products.

<Examples 14 to 26>
A plurality of plated products were obtained in the same manner as in Example 1. However, the salt water electrolysis test was set to 40 minutes.

<Performance evaluation method>
The performance of the plated product 1 obtained in Examples 1 to 26 was evaluated. FIG. 4 schematically illustrates the evaluation method. In order to improve reliability, this evaluation method has stricter conditions than, for example, JIS H 8502 "corrosion resistance test method for plating".
In the evaluation, the tip side of the strip pieces 20a to 20f was masked with the masking paint 50 (nitrocellulose resin dissolved in butyl acetate) for a length of 1.0 mm from the tip, and a part of the carrier 30, especially, particularly. A predetermined height above the connecting portion 21 of the strip pieces 20a to 20f is masked with a masking paint 60 (nitrocellulose resin dissolved in butyl acetate) and dried. The length between the exposed portion of the strip pieces 20a to 20f, that is, the connecting portion 21 and the masking paint 50 is set to 4.0 mm.
Then, the masked sample and a carbon rod having a diameter of 5 mm are placed vertically on a petri dish having a diameter of 150 mm. The sample should not touch the petri dish. The orientation of the sample is such that the surface that becomes the contact point at the time of mounting faces the carbon rod. The distance from the carbon rod is 100 mm.
The connecting portion so that the masking end surface is below the liquid level, in other words, the portion below the connecting portion 21 is in the liquid and the portion above the connecting portion 21 (masking paint 60) is outside the liquid. Fill with a 5 wt% sodium chloride aqueous solution with the vicinity of 21 as a boundary. From the electrode of the rectifier, a titanium clip with a length of 150 mm, a width of 5 mm, and a thickness of 1.0 mm is mediated as a measure against chlorine gas corrosion, the sample is connected to the anode, the carbon rod is connected to the cathode, and 5.0 V is applied by constant voltage control. And start the test. In addition, the 5 wt% sodium chloride aqueous solution used in the test must not be reused.
After 20 minutes, the application is stopped and the sample is taken out. By setting the test time to 20 minutes in this way, the test conditions are stricter than the gas corrosion test according to the above-mentioned general JIS standard. In order to remove sodium chloride adhering to the surface of the sample, the sample is rinsed with running water at 35 ° C., placed in a beaker filled with pure water, and washed with ultrasonic irradiation (23 kHz) for 5 minutes. Then, rinse with pure water and immediately dry.

Tables 1 and 2 below show the evaluation results of the examples. Table 1 shows the evaluation results obtained when the test time of the salt water electrolysis test was set to 20 minutes, and Table 2 shows the evaluation results obtained when the test time was set to 40 minutes so as to make the conditions even more severe. The evaluation results are shown below. These are the evaluation results under harsher conditions than the above JIS standard. In the table, "○" indicates that there is no abnormality, "△" indicates that there is pitting corrosion, etc., but the shape is maintained, and "×" indicates that the shape is not maintained due to missing, etc. , Mean each. The evaluation was performed visually. FIG. 5 is a photograph showing an example of each of these states. FIG. 5 (a) is an example of the state of “○”, (b) and (c) are examples of the state of “Δ”, and (d) is an example of the state of “×”, respectively. show.

Table 1

Table 2

3. 3. Summary As is particularly clear from Table 1, as shown in Examples 1 to 13, when the thickness of the nickel plating as the first plating layer is 1.0 to 4.0 μm, the second plating layer is used. Good results were obtained when the thickness of a certain platinum plating was 0.1 μm or more. According to Table 2, when the thickness of the nickel plating is 4.0 μm, as shown in Example 26, only “×” or “Δ” evaluation is obtained regardless of the thickness of the platinum plating. In addition, in Examples 14 to 26, when the thickness of the platinum plating as the second plating layer was 0.1 μm, only an “x” evaluation was obtained. The evaluation method in the present embodiment is Considering that the test conditions are harsher than the general gas corrosion test, it can be understood that it is sufficient that sufficient evaluation results are obtained in Table 1.

Furthermore, based on these evaluation results, this plated product is generally commercially available, at least in terms of corrosion resistance, if only the first plating layer as the base layer and the second plating layer as the finish layer provided on the base layer are included. It is clear that the same or better effect as the plated product can be obtained.

4. Modification Example As in the conventional case, the first plating layer 11 and the second plating layer 12 may be formed from a plurality of layers. FIG. 6 shows a cross-sectional view in the case where a plurality of first plating layers 11 are used, in this case, the first partial plating layer 11A and the second partial plating layer 11B, in the same manner as in FIG. The first partial plating layer 11A and the second partial plating layer 11B are laminated in order from the substrate 10 toward the second plating layer 12 and in contact with each other in the thickness direction "t", and each of them is in contact with each other. It functions as a part of the first plating layer 11. The second partial plating layer 11B is preferably laminated directly on the first partial plating layer 11A for ease of adjustment. For example, palladium-nickel plating can be used as the material of the first partial plating layer 11A, and for example, gold plating can be used as the material of the second partial plating layer 11B. However, in consideration of misfit, the difference between the lattice constant of the substrate 10 and the lattice constant of the first partial plating layer 11A, and the lattice constant of the first partial plating layer 11A and the lattice of the second partial plating layer 11B. The difference in constants and the difference between the lattice constants of the second partial plating layer 11B and the lattice constants of the second plating layer 12 shall be 15% or less, respectively.

Further, the lattice constant of the first partial plating layer 11A shall be equal to or less than the lattice constant of the second partial plating layer 11B, and the lattice constant of the second partial plating layer 11B shall be equal to or less than the lattice constant of the second plating layer 12. ..
Further, it is preferable that the total of the thickness of the first partial plating layer 11A and the thickness of the second partial plating layer 11B is the same as the thickness of the first plating layer 11 before making the plurality. This facilitates adjustment.

Although the example in which the first plating layer 11 is a plurality is shown, the second plating layer 12 may be a plurality. Further, of course, the surface plating 13 may be provided on the second plating layer 12. As the surface plating 13, for example, gold plating can be used.

It should be understood that the above description relates to a preferred embodiment and is merely representative of the article. It can be acknowledged that modifications and modifications of different embodiments will be readily apparent to those of skill in the art in the light of the teachings described above. Accordingly, alternative embodiments can be made without departing from the spirit of the articles and methods described in the appended claims.

10 Substrate 11 Underlayer (first plating layer)
11A First partial plating layer 11B Second partial plating layer 12 Finishing layer (second plating layer)

Claims (8)

With a conductive substrate,
A first plating layer having a thickness of about 1.0 to about 4.0 μm laminated on the surface of the substrate, and
A second plating made of a platinum group metal or an alloy thereof laminated on the other surface of the first plating layer located on the opposite side of the one surface on which the substrate is provided in the thickness direction of the first plating layer. Layers and
Equipped with
The difference between the lattice constant of the substrate and the lattice constant of the first plating layer, and the difference between the lattice constant of the first plating layer and the lattice constant of the second plating layer are 15% or less, respectively. Plated product. The plated product according to claim 1, wherein the thickness of the second plating layer is about 0.1 μm or more. The plated product according to claim 1 or 2, wherein the platinum group metal is platinum or rhodium. The plated product according to any one of claims 1 to 3, wherein the first plating layer is nickel or an alloy thereof. The plated product according to any one of claims 1 to 4, wherein the first plating layer is composed of a plurality of layers. The plurality of layers are laminated in order from the substrate toward the second plating layer in the thickness direction, and include at least first and second partially plated layers in contact with each other.
The difference between the lattice constant of the substrate and the lattice constant of the first partial plating layer, the difference between the lattice constant of the first partial plating layer and the lattice constant of the second partial plating layer, and the second. The difference between the lattice constant of the partial plating layer and the lattice constant of the second plating layer is 15% or less, respectively.
The lattice constant of the first partial plating layer is equal to or less than the lattice constant of the second partial plating layer.
The lattice constant of the second partial plating layer is equal to or less than the lattice constant of the second plating layer.
The plated product according to claim 5. The plated product according to any one of claims 1 to 6, wherein the substrate is made of copper, aluminum, or an alloy of copper or aluminum. The plated product according to any one of claims 1 to 7, wherein the plated product is a terminal fitting.

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