JP2009215632A - Metallic material for electric contact component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metallic material for electric contact component which improves operability of a switch being the electric contact component and has the improved adhesiveness and contact resistance of a noble metal coated layer after a high temperature treatment. <P>SOLUTION: At least two layers of intermediate layers are provided between a conductive base material and a novel metal layer. The conductive base material contains 1.5-4.2 mass% Ni and 0.3-1.4 mass% Si. In the relation of tensile strength among three angles of 0°. 45° and 90° relative to the rolling direction of the conductive base material, the maximum value is ≥600 MPa and the ratio between the maximum and minimum values is ≥85% and ≤100%. The intermediated layers includes a first intermediate metallic layer formed from nickel, cobalt and their alloy successively on the conductive base material in this order from one closer to the conductive base material and a second intermediate metallic layer formed from copper or a copper alloy, wherein the adhesion state of the conductive base material to the novel metal layer is kept after being heated at 300°C for 15 min in the atmosphere and the contact resistance after being heated at 300°C for 15 min in the atmosphere is ≤10 mΩ. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a metal material for electrical contact parts that is suitably used for electrical contact parts such as various switches used in electronic devices and the like.

  For electrical contact parts such as various switches typified by slide switches, tact switches, and multi-function switches (for example, multi-directional switches), copper or copper alloys having excellent electrical conductivity have been used in the past. However, in recent years, demands for improving contact characteristics have increased, and the number of cases using bare copper or copper alloys has decreased, and products having various surface treatments on copper or copper alloys are being manufactured and used. In particular, as a material that is widely used as an electrical contact component material, there is one in which a noble metal coating is applied to an electrical contact portion. Among them, noble metals such as gold (Au), silver (Ag), palladium (Pd), platinum (Pt), iridium (Ir), rhodium (Rh), ruthenium (Ru), the stability of the material, Because of its excellent electrical conductivity, it is used as a material for various electrical contact parts.

  By the way, in recent years, an operation push button switch (for example, a numeric keypad) and a multi-function switch (for example, a four-way switch) have been used for electronic devices such as mobile phones (see Patent Document 1). As a base material of a spring member constituting the contact portion of such a switch, a material obtained by press punching a rolled plate of stainless steel, phosphor bronze, brass, pure copper or the like is used. And in order to improve reliability, plating of Au, Ag, Pd, etc. is given (refer patent document 2).

JP 2001-229783 A JP 2005-2400 A

  However, in the conventional spring members disclosed in each patent document, the stroke feeling at the time of switch operation (feeling of pressing the switch) and the softness at the time of clicking may differ depending on the switch direction. There was a problem that the nature was not good.

  In addition, when silver plating was applied to a copper alloy such as phosphor bronze or brass, a phenomenon was observed in which the plating peeled off when heat treatment at about 300 ° C. was performed. This is an electrical contact component used at a high temperature of, for example, 50 ° C. or more, and various switches produced through a manufacturing process involving a heat treatment of about 300 ° C. such as a soldering process or a melting process (reflow process, etc.). However, the improvement in the adhesion of the noble metal coating layer has been urgently required.

  Therefore, in order to solve the above problems, the present invention provides a metal material for electrical contact parts that improves the operability of a switch that is an electrical contact part and improves the adhesion and contact resistance value of the noble metal coating layer after high-temperature heat treatment. The purpose is to provide.

  A first solving means of the present invention is a metal material for an electrical contact part in which a copper alloy material is used as a conductive base material and at least a part of the outermost surface thereof is coated with a noble metal layer, the conductive base material Is a copper-based precipitation type alloy, the tensile strength in the rolling direction of the conductive substrate, the tensile strength in the direction of 45 ° and the angle in the rolling direction is 90 °. With respect to the relationship between the three tensile strengths in the direction of tensile strength, the maximum value is 600 MPa or more, and the ratio between the maximum value and the minimum value of tensile strength is 85% or more and 100% or less, At least two intermediate metal layers are provided between the noble metal layer, the intermediate metal layer including a first intermediate metal layer and a second intermediate metal layer in order from the conductive substrate, The intermediate metal layer is nickel or an alloy thereof, cobalt or Is formed to a thickness of 0.005 to 1.0 μm by its alloy, and the second intermediate metal layer is formed to a thickness of 0.005 to 1.0 μm by copper or its alloy, The contact state between the conductive base material and the noble metal layer is maintained after heating in the atmosphere for 5 minutes, and the contact resistance value after heating in the atmosphere at 400 ° C. for 15 minutes is 10 mΩ or less.

  According to a second solution of the present invention, in the first solution, the noble metal layer is made of gold or an alloy thereof, silver or an alloy thereof, palladium or an alloy thereof, platinum or an alloy thereof, ruthenium or an alloy thereof. It is characterized by including.

  A third solving means of the present invention is characterized in that, in the first or second solving means, the noble metal layer has a thickness of 0.05 to 5.0 μm.

  According to a fourth solution of the present invention, in any one of the first to third solutions, the copper-based precipitation type alloy includes 1.5 to 4.2% by mass of nickel and 0.3 to 1.4. It is characterized by containing mass% silicon.

  According to a fifth solution of the present invention, in any one of the fourth solution, the copper alloy material may include 0.05 to 0.2 mass% magnesium, 0.1 to 0.5 mass% tin, It further comprises at least one selected from the group of 0.1 to 1.0% by mass of zinc and 0.05 to 0.5% by mass of chromium.

  A sixth solving means of the present invention is characterized in that, in any one of the first to fifth solving means, the metal layer provided on the surface side of the conductive substrate is provided by plating.

  According to the present invention, the copper alloy constituting the conductive base material is a copper-based precipitation type alloy, and the tensile strength in the rolling direction of the conductive base material and the tensile strength in which the angle formed with the rolling direction is 45 °. And the relationship between the three tensile strengths of the tensile strength in the direction of 90 ° with respect to the rolling direction, the maximum value is 600 MPa or more, the minimum value is 85% or more and 100% or less of the maximum value, and 300 ° C. 15 Since the contact state of the conductive base material and the noble metal layer is maintained after heating in the atmosphere for 5 minutes and the contact resistance value after the atmospheric heating test at 400 ° C. for 15 minutes is 10 mΩ or less, the switch is an electrical contact part Thus, it is possible to obtain a metal material for electrical contact parts that improves the adhesion and the contact resistance value of the noble metal coating layer after the high-temperature heat treatment.

  Preferred embodiments of the present invention will be described. The material for electrical contact components in the present invention is an electrical contact component in which a noble metal coating layer is applied to a conductive base material of a copper-based precipitation type alloy material (plate material, strip material, bar material, wire material, etc.) having a specific shape. Means general metal materials.

  As the copper-based precipitation type alloy used in the present invention, beryllium copper (for example, C17200, C17530, etc.), titanium copper (for example, C19900), chromium copper, iron-added copper alloy (for example, C19400), etc. can be applied. A Corson alloy containing (Ni) and silicon (Si) is recommended because of its excellent strength and conductivity. In the Corson alloy, Ni and Si are precipitated as intermetallic compounds to increase the strength.

  The precious metal layer may be subjected to rust prevention treatment for improving corrosion resistance, treatment for imparting lubricity (for example, formation of an organic film) or the like before the treatment (for example, organic film formation). It means that a noble metal or an alloy containing the noble metal as a main component appears on the outermost surface before formation).

  One or more noble metal layers may be formed. For example, a plurality of layers such as a gold coating layer on a silver coating layer and a gold coating layer on a palladium coating layer may be provided. Since the process becomes complicated and the effect of increasing the number of layers is saturated, at most three layers are preferable. The form of the coating may be one in which the entire surface of the strip is covered, or one that is coated only in a location that acts effectively as a contact material when it is press-formed as an electrical contact material. For example, it is formed in a stripe shape or a spot shape. Included.

  Here, when the electrical contact part is a shape that is desirably formed by processing a flat plate material, such as various switch contact parts, the shape of the electrical contact part material is a strip shape (ribbon shape / hoop shape). It is also preferably a plate shape, and the material plate thickness, plate width and the like can be used without particular limitation, but preferably a plate thickness of 0.03 to 0.5 mm and a plate width of 3 to 200 mm are suitable. Or after manufacturing to wide width, the method of cut | disconnecting to a required width | variety by slitting is also possible. In addition, when an electrical contact component does not ask | require a shape, the shape of a material for electrical contact components does not ask | require shapes, such as a board | plate material, a strip, a rod, a wire.

  According to the metal material for electrical contact parts according to the embodiment of the present invention, there are two or more intermediate metals between the conductive base material of the copper-based precipitation type alloy and the noble metal layer formed on the outermost surface. A layer is provided. Specifically, a first intermediate metal layer of nickel (Ni) or its alloy or cobalt (Co) or its alloy is provided from the substrate side, and a second intermediate metal layer of copper or its alloy is further provided thereon. It is done. FIG. 1 is a cross-sectional view showing an example of a metal material for electrical contact parts according to the first embodiment, and FIG. 2 is a cross-sectional view showing an example of a metal material for electrical contact parts according to the second embodiment. 1 and 2, 1 is a conductive substrate, 2 is a first intermediate metal layer, 3 is a second intermediate metal layer, and 4 is a noble metal layer.

The copper alloy constituting the conductive substrate is a Corson-based (Cu-Ni-Si) containing 1.5 to 4.2 mass% nickel (Ni) and 0.3 to 1.4 mass% silicon (Si). System) alloys. Moreover, about the mass ratio of Ni and Si, the range of 3-5 is preferable, and the range of 3.5-4.5 is more preferable. Furthermore, the closer to the mass ratio (about 4.2) of Ni ₂ Si which is a typical precipitate, the better. If the copper alloy constituting the conductive base material is a Corson alloy having the above composition, it is excellent in conductivity, springiness, and durability, so that the electrical contact component can be reduced in size and thickness. When Ni is less than 1.5% by mass (Si is less than 0.3% by mass), the strength as a conductive substrate becomes insufficient, and Ni exceeds 4.2% by mass (Si is 1.4% by mass). %), It is not preferable because the conductive base material tends to crack.

  Moreover, the following relationship is materialized regarding the tensile strength of an electroconductive base material. That is, (1) Tensile strength in the rolling direction, (2) Tensile strength in which the angle with the rolling direction is 45 °, and (3) Tensile strength in which the angle with the rolling direction is 90 °. Regarding the strength relationship, the maximum value of (1) to (3) is 600 MPa or more, and the ratio between the maximum value and the minimum value of the tensile strength of (1) to (3) is 85% or more and 100% or less. It is. The ratio between the maximum value and the minimum value of the tensile strength is preferably 90% or more and 100% or less, and more preferably 95% or more and 100% or less. The ratio between the maximum value and the minimum value of the tensile strength is closely related to the mechanical anisotropy when the metal material for electrical contact parts is processed as an electrical contact part. For example, when the electrical contact part is a multidirectional switch Directly affects the operability of the system. For this reason, it can be said that the ratio between the maximum value and the minimum value of the tensile strength is preferably as close to 100% as possible. When this relationship is not satisfied, when the maximum value of (1) to (3) is less than 600 MPa, the strength as the conductive substrate becomes insufficient, which is not preferable. Further, when the ratio between the maximum value and the minimum value of (1) to (3) is less than 85%, not only the operability of the switch using the electrical contact parts is impaired, but also, for example, a soldering process or a melting process ( Since the rate at which the noble metal layer is peeled off from the conductive substrate is rapidly increased after a manufacturing process involving a heat treatment at about 300 ° C. such as a reflow process, it is not preferable. This point of view has already been proposed by the present applicant in Japanese Patent Application No. 2007-237213.

  The thickness of the first intermediate metal layer is specified to be 0.005 to 1.0 μm. This is because if it is less than 0.005 μm, a hole called a pinhole is remarkably generated in the first intermediate metal layer, and oxygen that has infiltrated therefrom oxidizes the substrate surface and causes a decrease in adhesion, On the other hand, if the thickness exceeds 1.0 μm, a crack occurs in the first intermediate metal layer when the electric contact part material is pressed, and as a result, a crack occurs in the second intermediate metal layer and the noble metal layer. Diffusing material components causes problems such as increased contact resistance and corrosion. Thus, although the effect of improving heat-resistant adhesion is exhibited by forming the first intermediate metal layer within the specified thickness range, the range of 0.05 to 1.0 μm is preferable, and 0.1 to 0.00. The range of 5 μm is more preferable.

  The thickness of the second intermediate metal layer formed on the surface of the first intermediate metal layer is specified to be 0.005 to 1.0 μm. If it is less than 0.005 μm, the amount of Cu or an alloy thereof acting as an oxygen scavenger is insufficient, and the components of the first intermediate metal layer are easily oxidized, resulting in insufficient heat-resistant adhesion. Also, if it exceeds 1.0 μm, the amount of oxygen scavenger is sufficient, but when heated, Cu diffuses to the surface of the noble metal contact and is exposed to the surface, forming an oxide on the surface layer and increasing the contact resistance. This is inappropriate. Thus, although the effect of improving heat-resistant adhesion is exhibited by forming the second intermediate metal layer within the specified thickness range, the range of 0.05 to 0.5 μm is preferable, and 0.1 to 0. The range of 2 μm is more preferable.

  Further, the noble metal layer formed on the outermost surface of the conductive substrate is gold (Au) or an alloy thereof, silver (Ag) or an alloy thereof, palladium (Pd) from the viewpoint of stability and low contact resistance among noble metals. Alternatively, it is preferable to include any of an alloy thereof, platinum (Pt) or an alloy thereof, ruthenium (Ru) or an alloy thereof. In particular, Au, Ag, Pd or the following alloys containing these (Au—Co, Au—Pd, Au—Ag, Ag—Pd, Ag—Cu, Ag—Sn, Ag—Se, Ag—Sb, Pd—Ni) Is preferred.

  The thickness of these noble metal layers is defined by 0.05 to 5.0 μm. This is because if the thickness is less than 0.05 μm, a hole called a pin hole is generated in the noble metal layer, and therefore a potential difference is generated between the noble metal layer and the intermediate layer, and corrosion occurs to increase the contact resistance. On the other hand, if it exceeds 5.0 μm, it is not preferable because cracking is likely to occur in the plating due to press working or bending. Moreover, since expensive precious metals are used, it is not preferable in that the manufacturing cost increases. As described above, the noble metal layer exhibits a sufficient effect as a contact part material by being formed within the specified thickness range, but is preferably 0.05 to 2.0 μm, preferably 0.2 to 1.0 μm. More preferably, it is formed by.

  Moreover, as a copper alloy which comprises an electroconductive base material, 1.5-4.2 mass% nickel (Ni) and 0.3-1.4 mass% silicon (Si) are included, and the remainder is an inevitable impurity. And at least one selected from the group consisting of magnesium (Mg), tin (Sn), zinc (Zn), and chromium (Cr), in addition to a Corson (Cu—Ni—Si) alloy made of copper and copper. The strength can be improved by adding an appropriate amount of one. As for the content, Mg is 0.05-0.2 mass%, Sn is 0.1-0.5 mass%, Zn is 0.1-1.0 mass%, Cr is 0.05-0. It is preferably 5% by mass.

  Each metal layer (the first intermediate metal layer, the second intermediate metal layer, the noble metal layer, etc.) of the metal material for electrical contact parts can be formed by a clad method, a sputtering method, a vapor deposition method, or the like. In order to produce the product uniformly and with high productivity, it is desirable to form it by a plating method. Of these, the wet plating method is the most desirable because it has the lowest cost and good productivity.

  Hereinafter, the present invention will be described in more detail based on examples. The present invention is not limited to these.

[Example 1]
(Description of sample)
A Corson alloy strip having a thickness of 0.1 mm and a width of 180 mm was used as the conductive substrate. After pre-treatment of electrolytic degreasing and pickling on this strip, a plating component was prepared, and the metal materials for electrical contact parts of the present invention and comparative examples shown in Table 1 were obtained. Table 1 also shows the maximum value of the tensile strength of the conductive substrate and the ratio between the maximum value and the minimum value of the tensile strength. Tensile strength is a tensile test piece (JIS Z 2201-5 No. Specimen) having three directions, the rolling direction of the plate material, the angle formed with the rolling direction is 45 °, and the angle formed with the rolling direction is 90 °. ) Was cut out, and the tensile strength was measured according to JIS Z 2241. In addition, the average value is calculated by measuring three tensile strengths in each direction in this way, and the maximum value and the ratio between the maximum value and the minimum value of the tensile strength (average value) in the three directions are obtained. It was.

Here, it shows about the composition of the electroconductive base material shown by Table 1. FIG. Compositions X and Y are comparative examples as compositions. In addition, a number is the mass% and the remainder is copper (Cu) and inevitable impurities.
Composition A: Cu-2.3Ni-0.55Si-0.15Sn-0.5Zn-0.1Mg
Composition B: Cu-3.75Ni-0.9Si-0.15Sn-0.5Zn-0.1Mg
Composition C: Cu-2.0Ni-0.4Si
Composition D: Cu-3.0Ni-0.65Si-0.1Mg
Composition E: Cu-2.5Ni-0.56Si-0.5Zn
Composition F: Cu-2.5Ni-0.56Si-0.15Sn-0.5Zn-0.1Mg
Composition G: Cu-4.2Ni-1.4Si-0.15Sn-0.5Zn-0.1Mg
Composition H: Cu-1.5Ni-0.3Si-0.15Sn-0.5Zn-0.1Mg
Composition X: Cu-1.2Ni-0.3Si
Composition Y: Cu-4.2Ni-1.6Si

(Test conditions)
In order to obtain heat-resistant adhesion for the above metal materials for electrical contact parts, an atmospheric heating test for 15 minutes was performed at a heating temperature in the range of 300 ° C. to 450 ° C., and the tape peeling test (JIS) -H8504). The heat resistance adhesion evaluation, the normal state, the contact resistance value measurement after the atmospheric heating test at 400 ° C. for 15 minutes, and the pressability evaluation are shown in Table 2. For reference, Table 2 also shows the comparison of manufacturing costs in five stages, ◎ ○ △ ▲ ×, indicating that ◎ is better, and Δ to ◎ mean levels useful for actual mass production. . Specifically, ◎ is the minimum cost value to twice the minimum value, ◯ is the cost minimum value is 2 to 4 times, △ is the cost minimum value 4 to 8 times, and ▲ is the cost minimum value 8 to 16 times. Double and x mean higher than 16 times the minimum cost.

  Plating conditions and evaluation methods are shown below.

(Plating conditions)
[Ni plating]
Plating solution: Ni (NH ₂ SO ₃ H): 500 g / l, NiCl ₂ : 30 g / l, H ₃ BO ₃ : 30 g / l
Plating conditions: current density: 15 A / dm ² , temperature: 50 ° C.

[Co plating]
Plating solution: CoSO ₄ : 400 g / l, NaCl: 20 g / l, H ₃ BO ₃ : 40 g / l
Plating conditions: current density: 5 A / dm ² , temperature: 30 ° C.

[Cu plating]
Plating solution: CuSO ₄ .5H ₂ O: 250 g / l, H ₂ SO ₄ : 50 g / l, NaCl: 0.1 g / l
Plating conditions: current density: 6 A / dm ² , temperature: 40 ° C.

[Ag plating]
Plating solution: AgCN: 50 g / l, KCN: 100 g / l, K ₂ CO ₃ : 30 g / l
Plating conditions: current density: 0.5-3 A / dm ² , temperature: 30 ° C.

[Glossy Ag plating]
Plating solution: AgCN: 50 g / l, KCN: 100 g / l, K ₂ CO ₃ : 30 g / l, Na ₂ S ₂ O ₃ : 1.58 g / l
Plating conditions: current density: 1 A / dm ² , temperature: 30 ° C.

[Pd—Ni alloy plating: Pd / Ni (%) 80/20]
Plating solution: Pd (NH ₃ ) ₂ Cl ₂ : 40 g / l, NiSO ₄ : 45 g / l, NH ₄ OH: 90 ml / l, (NH ₄ ) ₂ SO ₄ : 50 g / l
Plating conditions: current density: 1 A / dm ² , temperature: 30 ° C.

[Pd plating]
Plating solution: Pd (NH ₃ ) ₂ Cl ₂ : 45 g / l, NH ₄ OH: 90 ml / l, (NH ₄ ) ₂ SO ₄ : 50 g / l
Plating conditions: current density: 1 A / dm ² , temperature: 30 ° C.

[Au-Co plating]
Plating solution: KAu (CN) ₂ : 14.6 g / l, C ₆ H ₈ O ₇ : 150 g / l, K ₂ C ₆ H ₄ O ₇ : 180 g / l, EDTA-Co (II): 3 g / l, piperazine: 2 g / l
Plating conditions: current density: 1 A / dm ² , temperature: 40 ° C.

[Ru plating]
Plating solution ... RuNOCl ₃ · 5H ₂ O: 10 g / l, NH ₂ SO ₃ H: 15 g / l
Plating conditions: current density: 1 A / dm ² , temperature: 50 ° C.

[Heat resistance adhesion test]
In a constant temperature layer (STPH-100 manufactured by ESPEC Corp.), a tape peeling test was performed after performing a heating test for 15 minutes for each of 300 ° C, 350 ° C, 400 ° C, and 450 ° C. As a tape used for the tape peeling test, “# 631S” manufactured by Teraoka Seisakusho Co., Ltd. was used. The test piece size was 30 mm in width and 50 mm in length (the length direction is the rolling direction of the conductive substrate). In the evaluation results, “◯” indicates no peeling, “Δ” indicates partial peeling, and “×” indicates peeling. The results are shown in Table 2.

[Contact resistance measurement]
Using the four-terminal method, contact resistance measurement was performed on a sample at the initial stage of coating (normal state) and a sample after an atmospheric heating test at 400 ° C. for 15 minutes. The measurement conditions were an Ag probe R = 2 mm, a load 10 g (= about 0.1 N), and a resistance value when 10 mA was energized. The results are shown in Table 2.

[Processability evaluation]
The obtained sample was cut into a width of 10 mm and a length of 30 mm (the length direction is the rolling direction of the conductive base material), and then V-bent (90 °) in a direction perpendicular to the rolling direction. (VH8000 manufactured by Keyence Co., Ltd.) was observed at 450 times, and the presence or absence of cracks was confirmed. The results are shown in Table 2.

  In each of Examples 1 to 26 of the present invention, the heat-resistant adhesion, contact resistance, and workability were all good. In contrast, Comparative Example 1 was inferior in heat-resistant adhesion and contact resistance because the first intermediate metal layer was not present. In Comparative Example 2, since the second intermediate metal layer was not present, the heat resistant adhesion was inferior. In Comparative Example 3, the heat resistance adhesion and contact resistance were inferior because the first intermediate metal layer was too thin. In Comparative Example 4, since the first intermediate metal layer was too thick, cracks occurred after bending. In Comparative Example 5, the contact resistance was inferior because the second intermediate metal layer was too thick. In Comparative Examples 6 to 7, since the noble metal layer was too thick, cracks occurred after bending. In Comparative Example 8, since the ratio of the maximum value and the minimum value of the tensile strength in the three directions of the conductive base material was less than 85%, all of heat resistance adhesion, contact resistance, and bending workability were inferior. In Comparative Example 9, since the amount of Ni contained in the conductive base material was small, all of heat resistant adhesion, contact resistance, and bending workability were inferior. In Comparative Example 10, since the amount of Si contained in the conductive substrate was large, all of heat resistant adhesion, contact resistance, and bending workability were inferior.

  That is, each example of the present invention is excellent in heat-resistant adhesion, contact resistance, and workability, the operability of the switch as an electrical contact part is improved, and the adhesion and contact resistance of the noble metal coating layer after high-temperature heat treatment It turns out that it is a metal material for electrical contact parts with improved values.

Sectional drawing which shows an example of the metal material for electrical contact components which concerns on the 1st Embodiment of this invention. Sectional drawing which shows an example of the metal material for electrical contact components which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Conductive base material 2 1st intermediate metal layer 3 2nd intermediate metal layer 4 Noble metal layer

Claims (6)

A metal material for electrical contact parts, in which a copper alloy material is a conductive base material and at least a part of the outermost surface is coated with a noble metal layer,
The copper alloy constituting the conductive substrate is a copper-based precipitation type alloy,
Regarding the relationship between the tensile strength in the rolling direction of the conductive substrate, the tensile strength in the 45 ° direction with respect to the rolling direction, and the tensile strength in the 90 ° direction with respect to the rolling direction, The maximum value is 600 MPa or more, and the ratio of the maximum value and the minimum value of the tensile strength is 85% or more and 100% or less,
At least two intermediate metal layers are provided between the conductive substrate and the noble metal layer,
The intermediate metal layer includes a first intermediate metal layer and a second intermediate metal layer in order of proximity to the conductive base material. The first intermediate metal layer is made of nickel or an alloy thereof, or cobalt or an alloy thereof by 0.005. The second intermediate metal layer is formed of copper or an alloy thereof to a thickness of 0.005 to 1.0 μm,
After the heating in the atmosphere at 300 ° C. for 15 minutes, the adhesion state between the conductive substrate and the noble metal layer is maintained,
A metal material for electrical contact parts, wherein the contact resistance value after heating in the atmosphere at 400 ° C. for 15 minutes is 10 mΩ or less.   2. The metal for electrical contact parts according to claim 1, wherein the noble metal layer includes any one of gold or an alloy thereof, silver or an alloy thereof, palladium or an alloy thereof, platinum or an alloy thereof, ruthenium or an alloy thereof. material.   The metal material for electrical contact components according to claim 1 or 2, wherein the noble metal layer has a thickness of 0.05 to 5.0 µm.   The copper-based precipitation type alloy includes 1.5 to 4.2% by mass of nickel and 0.3 to 1.4% by mass of silicon, according to any one of claims 1 to 3. Metal materials for electrical contact parts as described.   The copper alloy material is 0.05 to 0.2 mass% magnesium, 0.1 to 0.5 mass% tin, 0.1 to 1.0 mass% zinc, 0.05 to 0.5 mass%. The metal material for electrical contact parts according to claim 4, further comprising at least one selected from the group of% chromium.   The metal material for electrical contact components according to any one of claims 1 to 5, wherein the metal layer provided on the surface side of the conductive substrate is provided by plating.

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