WO2024202237A1

WO2024202237A1 - Metal material and sliding component

Info

Publication number: WO2024202237A1
Application number: PCT/JP2023/042409
Authority: WO
Inventors: 康則佐々木; 良聡小林; 明宏柿谷; 山田　真二
Original assignee: Ｊｘ金属株式会社
Priority date: 2023-03-30
Filing date: 2023-11-27
Publication date: 2024-10-03

Abstract

This metal material 1 has a base material 2 and a plating layer 3 formed on the base material 2. The plating layer 3 contains an amorphous layer 4 containing Ni. The metal material 1 is used for a sliding component 101 that slides, at the surface 5 of the plating layer 3, against the surface 55 of another metal material 51. The other metal material 51 includes a crystalline layer 54 containing Ni.

Description

Metallic materials and sliding parts

This specification discloses technology relating to metal materials in which a plating layer is formed on a substrate, and sliding parts.

In sliding parts in which one metal material slides against another during use, such as connectors, switches, gears, bearings, washers, etc., the metal material may have a plated layer formed on the base material in order to prevent metal diffusion, etc.

In this regard, for example, Patent Document 1 states, "...nickel-phosphorus alloy coatings in particular have characteristics such as high corrosion resistance, high lubricity, high hardness, and high resistivity, and are used as plating coatings for sliding members and piping equipment used under harsh conditions, as well as being commonly used as thin-film resistors in the electronics industry, or as a substitute for gold in connectors."

Patent Document 2 also states that "The bath of Composition Example 1 (paragraph [0016]) produces Ni-P alloy-CNT composite plating with a high phosphorus concentration, so-called high phosphorus type (P concentration: 12 to 13 mass%), and these composite plating films exhibit a low friction coefficient and high hardness. On the other hand, in terms of electromagnetic wave shielding properties, a film in which CNT is composited to a low phosphorus type Ni-P alloy (P concentration: 2 to 4 mass%) is desired."

Japanese Patent Application Publication No. 03-010086 JP 2010-215977 A

The metal materials used in the sliding parts mentioned above are required to have excellent wear resistance and to prevent the plating layer from wearing away even when repeatedly rubbed against other metal materials.

This specification provides a metal material with excellent wear resistance and a sliding part in which wear of the metal material is suppressed.

The metallic material disclosed in this specification has a substrate and a plating layer formed on the substrate, the plating layer including an amorphous layer containing Ni, and the metallic material is used in a sliding part in which the surface of the plating layer slides against the surface of another metallic material, the other metallic material including a crystalline layer containing Ni.

Furthermore, another metal material disclosed in this specification has a substrate and a plating layer formed on the substrate, the plating layer includes an amorphous layer, and the metal material is used in a sliding part in which the surface of the plating layer slides against the surface of another metal material, the other metal material including a crystalline layer that is softer than the amorphous layer.

The sliding part disclosed in this specification comprises a first metal material and a second metal material, the first metal material having a substrate and a plating layer formed on the substrate, the plating layer of the first metal material includes an amorphous layer containing Ni, and the second metal material includes a crystalline layer containing Ni, and the first metal material and the second metal material are used by sliding against each other on their respective surfaces.

The above metal materials have excellent wear resistance. The above sliding parts are designed to suppress wear of the metal materials.

1 is a partial cross-sectional view showing a metal material according to an embodiment of the present invention, taken along a direction perpendicular to a surface of the metal material; 2 is a similar cross-sectional view showing a schematic diagram of a sliding state when the metal material in FIG. 1 and another metal material are used as sliding parts. FIG. 4 is a similar cross-sectional view showing another example of a plating layer formed on a base material made of a metal material. FIG. FIG. 1 is a schematic diagram showing a microstrip line of a sample when measuring the transmission loss of a metal material. FIG. 2 is a diagram showing the shapes and dimensions of the terminal and flat plate used in Test Example 1. 1 shows the appearance of the flat plates and terminals after testing in Examples 1 and 2 and Comparative Examples 1 and 2 in Test Example 1, and the results of the chipped area of the cross section of the flat plates. 1 is a graph showing the relationship between frequency and transmission loss for each metal material in Test Example 2. 13 is a graph showing the relationship between frequency and transmission loss for each metal material in Test Example 3. 6 shows TEM images and diffraction images of each metal material in Test Example 4.

Hereinafter, the above-mentioned metal material and sliding part will be described in detail.
The metal material 1 illustrated in Fig. 1 has a substrate 2 and a plating layer 3 formed on the substrate 2. The metal material 1 is used for a sliding part 101 together with another metal material 51 as illustrated in Fig. 2.

The other metal material 51 is often a plated layer 53 formed on a base material 52, like the metal material 1. However, the plated layer 3 of the metal material 1 includes an amorphous layer 4. Meanwhile, the other metal material 51 includes a crystalline layer 54. In one embodiment, both the amorphous layer 4 of the metal material 1 and the crystalline layer 54 of the other metal material 51 contain Ni. In another embodiment, the crystalline layer 54 of the other metal material 51 is softer than the amorphous layer 4 of the metal material 1. The sliding part 101 is used by sliding the metal material 1 and the other metal material 51 on the

surfaces

5, 55 of the respective

plated layers

3, 53, as shown by the arrows in FIG. 2.

As described above, when the plating layer 3 of the metal material 1 includes an amorphous layer 4, while the other metal material 51 that slides against it includes a crystalline layer 54, and when the amorphous layer 4 and the crystalline layer 54 contain Ni and/or the crystalline layer 54 is softer than the amorphous layer 4, the metal material 1 and the other metal material 51 have excellent wear resistance. In this case, although details will be described later in the Examples section, wear of the

plating layers

3 and 53 is significantly suppressed when the metal material 1 and the other metal material 51 slide against each other. Therefore, the metal material 1 of the embodiment described here exhibits excellent wear resistance, and the sliding part 101 can be said to be one in which wear of the metal materials 1 and 51 is suppressed.

Note that, when it is necessary to distinguish between the two metal materials 1, 51 that the sliding part 101 has, one of them, the metal material 1, will be referred to as the "metal material" or the "first metal material", and the other metal material 51 will be referred to as the "other metal material" or the "second metal material". In explanations common to both the two metal materials 1, 51, they may be simply referred to as the "metal material".

(Substrate)
The material of the

base material

2, 52 of the metal material 1, 51 is not particularly limited and may be any metal or alloy. The material of the

base material

2, 52 may be, for example, Cu (copper), Al (aluminum), Fe (iron), or an alloy containing at least one of them.

From the viewpoint of having high electrical conductivity and strength, the material of the

base material

2, 52 is preferably Cu or a Cu alloy, more specifically, phosphor bronze, brass, Corson copper, oxygen-free copper, tough pitch copper, etc. In particular, the materials of the

base material

2, 52 may be C11000, C10200, C19400, C70250, C26000, C52100, etc., which are standards established by the Copper Development Association (CDA).

The substrate 2 of the metal material 1 and the substrate 52 of the other metal material 51 may be made of the same material, but may also be made of different materials. The dimensions and shapes of the

substrates

2 and 52 may be changed as appropriate depending on the sliding parts in which the metal materials 1 and 51 are used.

(Amorphous layer)
The amorphous layer 4 constitutes at least a part of the plating layer 3 of the metal material 1. Typically, the amorphous layer 4 contains Ni (nickel) as a main component, which is an element of more than 50 mass %, but is not limited thereto.

The amorphous layer 4 containing Ni preferably further contains P (phosphorus). The Ni-P amorphous layer 4 has a dense amorphous structure, and therefore tends to be harder than the crystalline layer 54 described below, which contains mainly Ni. The metal material 1 used in sliding contact with another metal material 51 containing a crystalline layer 54 whose main component is Ni preferably contains Ni and P.

Furthermore, the amorphous layer 4 containing Ni and P is non-magnetic, which reduces the dielectric loss in the transmission loss. Therefore, the metal material 1 containing such an amorphous layer 4 can be suitably used in high-frequency components, particularly sliding components 101, through which a specific high-frequency internal signal flows, as described below.

The amorphous layer 4 containing Ni and P often has an amorphous structure when the P content is 8 mass% or more. The P content of the amorphous layer 4 is preferably 8 mass% to 15 mass%. If the P content is 15 mass% or less, the decrease in the conductivity of the amorphous layer 4 due to the inclusion of P can be suppressed. More preferably, the P content is 10 mass% to 13 mass%.

When the amorphous layer 4 contains Ni, it is also preferable that it further contains W (tungsten). The Ni-W amorphous layer 4 also has a dense amorphous structure and is harder than the Ni crystalline layer 54, and is expected to have the effect of improving wear resistance, similar to Ni-P. The W content of the amorphous layer 4 containing Ni and W is preferably 20% by mass to 40% by mass.
In addition, when the amorphous layer 4 contains Ni, it may further contain P and W.

To measure the P content, an electron probe microanalyzer (EPMA, JXA-8500F manufactured by JEOL Ltd.) can be used. More specifically, the X-ray intensity at the peak position of P (197.235 mm) is measured for each of the standard specimen and the sample using the electron probe microanalyzer, and the P content (at%) is calculated using the formula: P content (at%) = (average value of X-ray intensity of sample) ÷ (average value of X-ray intensity of standard specimen) × 50. The measurement conditions for the standard specimen are as follows: standard specimen: InP wafer (P content 50 at%), crystal used: PETH, X-ray used: Kα, acceleration voltage 15 kV, irradiation current 1 × 10 ^-7 A, beam diameter 10 μm, and under these measurement conditions, the X-ray intensity at the peak position of P (197.235 mm) of the standard specimen is measured five times, and the average value is calculated. In measuring the sample, the central portion of the sample of the metal material 1 having the amorphous layer 4 formed on the substrate 2 is measured five times under the same measurement conditions as those for the standard sample, and the average value of the X-ray intensity at the P peak position (197.235 mm) is calculated.
The W content can be measured by TEM-EDX (energy dispersive X-ray spectroscopy) using a JEM-2100F manufactured by JEOL Ltd. More specifically, the W content is measured at the center of the Ni-W layer in the thickness direction. The measurement of the W content by TEM-EDX (energy dispersive X-ray spectroscopy) can be performed as follows.
Equipment (TEM): Field emission transmission electron microscope (JEM-2100F) manufactured by JEOL Ltd.
Equipment (EDX): Energy dispersive X-ray analyzer (JED-2300T) manufactured by JEOL Ltd.
STEM image observation + EDX analysis Mode: STEM mode Acceleration voltage: 200 kV
Spot size: 0.15 nm
Magnification: 80,000 times

In the amorphous layer 4 containing Ni and P or W, the remainder other than P or W is often substantially composed of Ni, but it may also contain at least one impurity selected from the group consisting of Cu, Pb, and Zn in a total amount of 15 mass ppm or less.

The fact that the amorphous layer 4 has an amorphous structure can be confirmed by processing a cross section of the metal material 1 with an FIB-SIM (SMI3050SE, manufactured by Hitachi High-Technologies Corporation) and observing the cross section with a TEM (JEM-2100F, manufactured by JEOL Ltd.).

The amorphous layer 4 of the metal material 1 may be harder than the crystalline layer 54 of the other metal material 51. The Vickers hardness of the amorphous layer 4 may be 500 Hv to 600 Hv. The Vickers hardness of the crystalline layer 54 will be described later, but it is preferable that the difference in Vickers hardness between the amorphous layer 4 and the crystalline layer 54 is 100 Hv or more, more preferably 150 Hv or more, and particularly preferably 150 Hv to 300 Hv. It is believed that wear of the metal materials 1, 51 is suppressed during sliding on the sliding part 101 due to such a difference in hardness between the amorphous layer 4 and the crystalline layer 54.

The Vickers hardness of the amorphous layer 4 and the crystalline layer 54 can be measured using a microhardness tester MHT-2 manufactured by Matsuzawa Seiki Seisakusho Co., Ltd. (currently Matsuzawa Corporation). More specifically, the metal materials 1 and 51 are filled with acrylic resin while standing vertically, cut down to the measurement point, polished, and then a square pyramidal diamond indenter is pressed into the amorphous layer 4 and the crystalline layer 54, and the diagonal length of the depression created after the test force is released is measured. The test conditions are a test force of 500 gf and a holding time of 10 seconds, and the diagonal length is measured by taking the average of the X and Y measurements. The measured value is the median value of five measurements, and the hardness is calculated from the Vickers hardness calculation table based on this median value and the test force.

The thickness of the amorphous layer 4 is preferably 1 μm to 6 μm. If the thickness of the amorphous layer 4 is less than 1 μm, pits and pinholes are likely to occur, and corrosion resistance may decrease. On the other hand, if the thickness of the amorphous layer 4 exceeds 6 μm, there is a concern that cracks may occur when the metal material 1 is bent due to the hardness of the amorphous layer 4. The thickness of the amorphous layer 4 can be measured by a fluorescent X-ray thickness meter. The thicknesses of layers other than the amorphous layer 4 of the plating layer 3 and the thicknesses of other plating layers described later can also be measured in the same manner. The plating thickness can be measured by a fluorescent X-ray thickness meter as follows.
Equipment: Fluorescent X-ray thickness gauge FT9500X manufactured by Hitachi High-Tech Corporation
X-ray tube: Mo
Detector: drift type semiconductor detector X-ray optical system: polycapillary system Beam diameter: 30 μm
Measurement method: Thin film FP (Fundamental Parameter) method

In order to form the amorphous layer 4 on the substrate 2 during the production of the metallic material 1, for example, a plating bath for the substrate 2 is a nickel sulfate bath, and nickel (II) sulfate hexahydrate or the like is added to set the nickel sulfate concentration to 205 g/L to 295 g/L, the phosphorous acid concentration to 68 g/L to 95 g/L, the current density to 7 A/dm ² to 13 A/dm ² , and the solution temperature to 55° C. to 65° C. Alternatively, the amorphous layer 4 can be formed by electroless plating instead of electrolytic plating.

(Crystalline Layer)
When the other metal material 51 is a plated layer 53 formed on a base material 52 , at least a portion of the plated layer 53 contains a crystalline layer 54 .

The crystalline layer 54 has, for example, the same main component as the main component of the amorphous layer 4 described above, and typically contains Ni as the main component, but is not limited to this. Furthermore, in this case, the Ni content can be nearly 100 mass % and the crystalline layer 54 can be made of Ni alone. However, the crystalline layer 54 may also contain other elements. The Ni content can be measured using an electron probe microanalyzer (EPMA, JXA-8500F manufactured by JEOL Ltd.).

The crystalline layer 54 may be softer than the amorphous layer 4 described above. The Vickers hardness of the crystalline layer 54 may be 200Hv to 400Hv.

The thickness of the crystalline layer 54 is preferably 1 μm to 6 μm. If the thickness of the crystalline layer 54 is less than 1 μm, pits and pinholes are likely to occur, and corrosion resistance may decrease. On the other hand, if the thickness of the amorphous layer 4 exceeds 6 μm, there is a concern that cracks may occur when the other metal material 51 is bent.

The crystalline layer 54 can be formed by, but is not limited to, subjecting the base material 52 to non-gloss, semi-gloss, roughened Ni plating. The plating solution may be, for example, a nickel sulfamate plating solution, with a current density of 3 A/ ^dm2 to 20 A/ ^dm2 and a solution temperature of 40°C to 60°C.

(Top layer)
The

plating layer

3, 53 of the metal material 1, 51 may include a top layer containing at least one metal selected from the group consisting of Au, Ag, Sn, Pd and Cu. For example, Fig. 3 shows an example of the metal material 11 in which a top layer 16 is further formed on an amorphous layer 14 on a substrate 12. The top layer may be formed on other metal materials.

In this case, the outermost layer 16 is exposed on the surface 15 of the plating layer 13, and since the outermost layer 16 of the above material is relatively soft and thin, it is considered that it has almost no effect on the wear resistance. When the outermost layer 16 is provided, the transmission loss can be further reduced due to the high electrical conductivity, making the metal material 11 even more suitable for use in sliding parts that are also high-frequency parts. This is because the influence of the skin effect is strong in high-frequency parts.

The thickness of the outermost layer 16 may be 0.005 μm to 5 μm. If the thickness of the outermost layer 16 is too thin, it may not be possible to reduce transmission loss significantly, whereas if it is too thick, there is a concern that there may be no change in transmission loss, that there may be a slight effect on abrasion resistance, and that the cost of precious metals may be high.

For example, when the outermost layer 16 is formed by Au-Co plating (hard plating), the Au content of the outermost layer 16 may be about 99.7% by mass. When the outermost layer 16 is formed by pure Au plating (soft plating), the Au content of the outermost layer 16 may be nearly 100% by mass. When the outermost layer 16 contains other metals (Ag, Sn, Pd, or Cu), the content of the metal may be nearly 100% by mass. In addition, the outermost layer 16 may further contain Co, such as Au-Co. In addition, it is also possible to form two or more outermost layers of different materials. The metal content of the outermost layer 16 can be measured by using X-ray photoelectron spectroscopy (XPS, 5600MC manufactured by ULVAC-PHI, Inc.). The measurement conditions for XPS can be as follows.
Ultimate vacuum: 5.7×10 ^-7 Pa
Detection diameter: 800 μm
Excitation source: MgK
Output: 400W
Incident angle: 81 degrees Take-off angle: 45 degrees Neutralization gun: None Sputtering conditions Ion species: Ar+
Acceleration voltage: 2 kV
Sweep area: 3mm x 3mm
Rate: 1.7 nm/min ( _SiO2 equivalent)

During the manufacture of the metal material 11, in order to form the outermost layer 16, the base material 12 on which the amorphous layer 14 has been formed can be plated using an appropriate plating solution depending on the material of the outermost layer 16. As the plating solution, for example, in the case of the outermost layer 16 containing Ag, Silbrex Bright HS manufactured by EEJA or the like can be suitably used, and in the case of the outermost layer 16 containing Au, a hard Au plating solution or the like can be suitably used. For example, in Ag plating, the current density may be 5 A/dm ² to 25 A/dm ² and the solution temperature may be 30° C. to 60° C. Also, for example, in Au plating, the current density may be 5 A/dm ² to 60 A/dm ² and the solution temperature may be 50° C. to 60° C.

(Transmission loss)
The metal material 1 has a small transmission loss, and preferably has an absolute value of 4 dB or less when a current of a frequency of 10 GHz is passed through it. The transmission loss is often measured as a negative value, and the smaller the absolute value is and the closer to zero it is, the smaller the transmission loss is, and the more desirable the metal material 1 is for the sliding part 101, which is also a high-frequency part.

The transmission loss of the metal material 1 can be measured using a network analyzer. More specifically, as a sample to be set in the network analyzer, a microstrip line is used in which a dielectric layer is provided on a copper foil, and further, on the dielectric layer, a copper wiring with a plating layer formed around it is provided. To prepare this sample, a metal foil made of the material of the substrate 2 is bonded to each side of the dielectric layer by a heat press at 300°C, and then the metal foil on one side is made into wiring by circuit etching, and plating corresponding to the plating layer 3 is applied around the wiring. The wiring corresponds to the substrate. This sample is set in a network analyzer (Keysight N5247A) to measure the passing power and reflected power of the AC current passed through the sample, and the transmission loss can be calculated from the voltages P1 and P2 by the formula: transmission loss = 10 x log (P2/P1). Measurements are performed on four microstrip lines of the sample, and the average value is taken as the transmission loss.

(Sliding parts)
The sliding component 101 includes a first metal material 1 as the metal material 1 and a second metal material 51 as another metal material 51 .

In the sliding part 101, the surface 5 of the plating layer 3 of the first metal material 1 and the surface 55 of the plating layer 53 of the second metal material 51 are pressed against each other in a direction perpendicular to the surfaces 5, 55 (the vertical direction in FIG. 2), and as shown in FIG. 2, the first metal material 1 and the second metal material 51 may be displaced in opposite directions relative to each other in a direction roughly along the surfaces 5, 55 (the horizontal direction in FIG. 2).

In this manner, when the first metal material 1 and the second metal material 51 are caused to slide on the

surfaces

5, 55 of the plating layers 3, 53, the plating layers 3, 53 may rub against each other and wear away. In contrast, as described above, when the plating layer 3 of the first metal material 1 includes an amorphous layer 4 and the plating layer 53 of the second metal material 51 includes a crystalline layer 54, and the amorphous layer 4 and the crystalline layer 54 contain Ni and/or the crystalline layer 54 is softer than the amorphous layer 4, wear of the plating layers 3, 53 can be effectively suppressed.

If one of the metal materials 1 or 51 of the sliding part 101 has a convex portion protruding toward the

surface

55 or 5 of the opposing other metal material 51 or 1, it is preferable that the first metal material 1 has a convex portion provided on the surface 5. This is because, when a convex portion is provided on the first metal material 1 including the hard amorphous layer 4 and this is slid against the second metal material 51 including the soft crystalline layer 54, the result was that wear was suppressed compared to when a convex portion is provided on the second metal material 51. Therefore, it is preferable that the first metal material 1 has a convex portion protruding toward the surface 55 side of the second metal material 51 and sliding against the surface 55 while being pressed against the surface 55 when used in the sliding part 101.

Furthermore, when either one of the metal materials 1 or 51 has a pressing portion that rubs against the

surface

55 or 5 of the opposing other metal material 51 or 1 while being pressed against the

surface

55 or 5 by the force of a spring material or the like, it is preferable that the first metal material 1 has a pressing portion provided on the surface 5. Such a pressing portion may be the above-mentioned convex portion.

For example, if the sliding part 101 is a board-to-board connector, it is preferable that the receptacle having the convex portion of the board-to-board connector is made of the first metal material 1, and the plug is made of the second metal material 51. Also, of the two metal materials of the sliding part 101, it may be preferable that one of the metal materials that is biased toward the other metal material by a spring material such as a leaf spring is made of the metal material 1.

The sliding part 101 described above is not particularly limited as long as the two metal materials 1, 51 slide against each other when in use, but can be, for example, a connector, switch, gear, bearing, washer, etc.

In particular, the embodiment described here may be able to reduce transmission loss in the metal materials 1, 51, and is therefore effective when applied to the sliding part 101, which is a high-frequency part through which a current of a frequency of 1 GHz to 15 GHz, typically 7 GHz to 15 GHz, flows. Examples of such high-frequency sliding parts 101 include connectors and switches mounted on communication devices such as in-vehicle radar and mobile phones, such as smartphones. In recent communication devices, electrical signals in such high-frequency bands are used due to the increase in communication speed and the increase in the amount and diversification of information, and in the transmission of high-frequency electrical signals, it is necessary to reduce transmission loss not only during propagation through space but also inside the communication device.

Next, the effects of the metal materials and sliding parts mentioned above have been confirmed through testing and are explained below. However, the explanation here is merely for illustrative purposes and is not intended to be limiting.

(Test Example 1)
A terminal and a flat plate having the shape and dimensions shown in Fig. 5 were prepared. The protruding portion of the terminal was set to protrude from the flat surface by a height of 30 μm. Both the terminal and the flat plate had a base material made of a copper alloy containing 0.12 mass% Sn (NKE012 manufactured by JX Metals Corporation) and having a thickness of 0.15 mm. The longitudinal direction of both the terminal and the flat plate was set to be perpendicular to the rolling direction of the base material.

In Example 1, the flat plate was plated with Ni plating to a thickness of 1.5 μm, and the terminals were plated with Ni-P plating to a thickness of 1.5 μm (P concentration: 11% by mass). In Example 2, the flat plate was plated with Ni-P plating to a thickness of 1.5 μm (P concentration: 11% by mass), and the terminals were plated with Ni plating to a thickness of 1.5 μm.

In Comparative Example 1, both the flat plate and the terminals were plated with Ni plating to a thickness of 1.5 μm. In Comparative Example 2, both the flat plate and the terminals were plated with Ni-P plating to a thickness of 1.5 μm (P concentration 11% by mass).

For each of the terminals and flat plates of Examples 1 and 2 and Comparative Examples 1 and 2, a load was applied to the terminal and the terminal was caused to slide with the protruding portion of the terminal in contact with the flat plate under the following conditions.
Load: 200g
Sliding direction: perpendicular to the rolling direction of the substrate Sliding distance: 24 mm/1 round trip Sliding speed: 960 mm/min
Number of strokes: 20 times

The plate after sliding was observed with a laser microscope (Keyence Corporation's shape analysis laser microscope VK-X1000) and the scraped area on the cross section was measured. The measurement conditions were: scan mode: laser confocal, shooting magnification: 1200x, measurement size: standard (1024x768), measurement pitch: 0.13μm.

As a result, the scraped area was 33 ^μm in Example 1, 425 ^μm in Example 2, 1981 ^μm in Comparative Example 1, and 1079 μm in Comparative Example ^2. The appearances of the flat plates and terminals after the tests in Examples 1 and 2 and Comparative Examples 1 and 2, and the scraped area of the cross section of the flat plates are shown in FIG.

　Until now, it was thought that the harder the two metal materials that slide against each other, the higher the wear resistance would be. In contrast, the above results of Test Example 1 show that wear resistance is improved when one substrate is Ni-P plated and the other substrate is Ni plated, compared to when both substrates are Ni-P plated, which is harder than Ni plating. The layer formed on the substrate by Ni-P plating is an amorphous layer, and the layer formed on the substrate by Ni plating is a crystalline layer.

In addition, the Vickers hardness of the amorphous layer formed by Ni-P plating was 500 Hv, while the Vickers hardness of the crystalline layer formed by Ni plating was 300 Hv.

Furthermore, wear was suppressed more in Example 1, where the terminal with the convex portion contained an amorphous layer and the flat plate contained a crystalline layer, than in Example 2, where the opposite was true. The reason for this is not entirely clear, but it is thought to be important that the tip of the convex portion (real contact surface) is hard enough not to deform when shear stress is applied to the convex portion during sliding. If the tip of the convex portion were to deform, the real contact area would increase and greater stress would be applied, generating wear powder, and it is presumed that the convex portion would become entangled in this wear powder, making it easier to scrape the flat plate.

In addition to the above tests, it was separately confirmed that applying a 1 μm thick Au plating (outermost layer) to the crystalline Ni plating layer or the amorphous Ni-P plating layer of the flat plate and terminals did not affect the magnitude of wear as in the above Examples 1 and 2 and Comparative Examples 1 and 2. The reason that the provision of the outermost layer does not affect wear resistance is believed to be because outermost layers of Au, Ag, Sn, Pd, Cu, etc. are softer and thinner than Ni and Ni-P. The outermost layer is provided for the purpose of improving electrical conductivity reliability, and even if it wears slightly due to sliding, reliability does not decrease.

(Test Example 2)
The transmission loss of each of the metal material having a matte Ni plating on the substrate and the metal material having a Ni-P plating on the substrate was measured using a network analyzer (N5247A manufactured by Keysight).

In the preparation of the microstrip line, which is a sample to be set in the network analyzer, a 50 μm thick LCP resin was used as the dielectric layer, and a 12 μm thick oxygen-free copper foil was used as the metal foil. One side of the oxygen-free copper foil was etched to form a wiring with a width of 124 μm. As plating for this wiring, a matte Ni plating was performed using a nickel sulfamate plating solution under the conditions of a current density of 10 A/dm ² and a solution temperature of 60° C. As a result, a Ni layer was formed around the wiring. On the other hand, a Ni sulfate bath was used as the plating bath for Ni-P plating, and the conditions were Ni(II) sulfate hexahydrate: 250 g/L, phosphorous acid: 82 g/L, current density: 10 A/dm ² , and temperature: 60° C. As a result, a Ni-P layer with a P content of 12 mass% was formed around the wiring. The thickness of each Ni layer and Ni-P layer was 2 μm.

The matte Ni-plated sample and the Ni-P-plated sample were each set in a network analyzer, and the transmission loss was measured using the method described above. The results are shown in Figure 7.

Figure 7 shows that the absolute value of the transmission loss of the Ni-P plated sample is smaller than that of the Ni plated sample at frequencies below approximately 15 GHz.

(Test Example 3)
For metal material samples in which an outermost layer was formed by plating Ag or Au to a thickness of 0.3 μm on the Ni layer of the sample of Test Example 2, the transmission loss was measured in the same manner as in Test Example 2. The results are shown in FIG.

For Ag plating, Silbrex Bright HS manufactured by EEJA was used, and the conditions were a current density of 10 A/ ^dm2 and a solution temperature of 60°C. For Au plating, a hard Au plating solution was used, and the conditions were a current density of 10 A/ ^dm2 and a solution temperature of 60°C.

As can be seen from Figure 8, there is a tendency for the absolute value of transmission loss to decrease by providing a top surface layer. This is presumably because, since the skin effect is strongly evident in the high frequency range, coating the top surface layer with a highly conductive precious metal reduces the conductive loss in transmission loss. As a result, Ag, which has a higher conductivity than Au, reduces transmission loss. Figure 8 shows data for a top surface layer formed on a Ni layer, but from a mechanical standpoint, it is believed that similar results would be obtained even if the Ni layer were replaced with a Ni-P layer.

(Test Example 4)
A metal material having a crystalline layer or an amorphous layer formed on a substrate made of oxygen-free copper (C1020) was produced by applying a matte Ni plating or Ni-P plating to the substrate.

Here, the conditions for the matte Ni plating and the Ni-P plating were the same as in Test Example 2. The P content of the Ni-P plating was 10 mass %. This is thought to be due to variation.

The cross-sections of each of the above metal materials were processed using a FIB-SIM (SMI3050SE, manufactured by Hitachi High-Technologies Corporation) and the cross-sections were observed using a TEM (JEM-2100F, manufactured by JEOL Ltd.). As a result, the TEM image and diffraction image shown in Figure 9 were obtained. From Figure 9, it can be seen that the amorphous layer (Ni-P layer) has an amorphous structure, since no crystal structure can be confirmed in the TEM image. It can also be seen that the amorphous layer (Ni-P layer) has an amorphous structure, since a concentric halo pattern, rather than spots, can be confirmed in the diffraction image. The fact that the amorphous layer has an amorphous structure is confirmed by the fact that no crystal structure can be confirmed in the TEM image of the Ni-P layer. Similarly, the fact that the crystalline layer (Ni layer) has a crystalline structure is confirmed by the fact that a crystal structure can be confirmed in the TEM image.

The results of the above tests, particularly Test Example 1, suggest that the metal materials and sliding parts described above have excellent wear resistance and suppress the occurrence of wear of the metal materials.

1, 11 The metal material (first metal material)
2, 12

Substrate

3, 13

Plating layer

4, 14 Amorphous layer 5, 15 Surface 16 Outermost layer 51 Other metal material (second metal material)
52 Base material 53 Plating layer 54 Crystalline layer 55 Surface 101 Sliding part

Claims

A metal material having a substrate and a plating layer formed on the substrate,
The plating layer includes an amorphous layer containing Ni,
The metallic material is used in a sliding part in which the surface of the plating layer slides against the surface of another metallic material, the other metallic material including a crystalline layer containing Ni.
A metal material having a substrate and a plating layer formed on the substrate,
The plating layer includes an amorphous layer,
The metal material is used in a sliding part in which the surface of the plating layer slides against the surface of another metal material, and the other metal material includes a crystalline layer that is softer than the amorphous layer.
The metallic material according to claim 2, wherein the main component of the amorphous layer of the metallic material is the same as the main component of the crystalline layer of the other metallic material.
The metallic material according to claim 3, wherein the main component is Ni.
The metallic material according to any one of claims 1 to 4, wherein the amorphous layer of the metallic material contains P and/or W.
The metal material according to any one of claims 1 to 4, wherein the plating layer of the metal material includes an outermost layer containing at least one metal selected from the group consisting of Au, Ag, Sn, Pd, and Cu.
The metal material according to any one of claims 1 to 4, wherein the difference between the Vickers hardness of the amorphous layer of the metal material and the Vickers hardness of the crystalline layer of the other metal material is 100 Hv or more.
The metal material according to any one of claims 1 to 4, wherein the sliding part has a pressing part that is pressed against the surface of the other metal material and slides against the surface.
The metal material according to claim 8, wherein the pressing portion is a protrusion that protrudes toward the surface side of the other metal material.
The metallic material according to any one of claims 1 to 4, wherein the sliding part is a high-frequency part through which a current with a frequency of 1 GHz to 15 GHz flows.
The metal material according to any one of claims 1 to 4, wherein the sliding part is a connector or a switch.
A sliding component comprising a first metal material and a second metal material,
The first metal material has a substrate and a plating layer formed on the substrate,
The plating layer of the first metal material includes an amorphous layer containing Ni, and the second metal material includes a crystalline layer containing Ni,
A sliding component, in which the first metal material and the second metal material are used by sliding against each other on their surfaces.
The sliding part according to claim 12, wherein the amorphous layer of the first metal material contains P and/or W.
The sliding part according to claim 12 or 13, wherein the plating layer of the first metal material includes an outermost layer containing at least one metal selected from the group consisting of Au, Ag, Sn, Pd, and Cu.
The sliding part according to claim 12 or 13, wherein the first metal material has a pressing portion that is pressed against the surface of the second metal material and slides against the surface.
The sliding component according to claim 15, wherein the pressing portion is a protrusion that protrudes toward the surface side of the second metal material.
The sliding part according to claim 12 or 13, which is a high-frequency part through which a current with a frequency of 1 GHz to 15 GHz flows.
The sliding part according to claim 12 or 13, which is a connector or a switch.