Electrical contact material, and contacts, terminals and connectors using the same

Abstract

To provide an electric contact material that has excellent wear resistance, less influenced by the properties of its substrate, and a contact, a terminal and a connector each including the same.SOLUTION: An electric contact material includes a conductive substrate, and a silver-containing layer that contains silver and is provided on at least part of the surface of the conductive substrate. In a cross section of the electric contact material, the silver-containing layer has an average GAM value of 0.20° or more and 3.00° or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an electrical contact material, and a contact, terminal, and connector using the same. [Background technology]

[0002] In recent years, automobiles have been increasingly adopting electrified drivetrains in order to achieve fuel economy. While this trend has dramatically increased the amount of current passing through the electrical wires between the battery, inverter, and motor, heat generated by electrical contacts and connectors has become a problem. For this reason, materials used for contacts and connectors are made of highly conductive pure copper, dilute copper alloys, or Corson alloys, with a nickel underplating applied to the surface, and then a silver or silver alloy plating applied over the underplating. However, because silver is a metal prone to adhesive wear, the silver plating is easily scraped off during sliding. This has the drawback of increasing the contact resistance of silver-plated materials due to wear of the silver plating.

[0003] To address these drawbacks, Patent Document 1, for example, describes a silver-plated terminal for connectors in which the surface of a copper or copper alloy base material is coated with a silver plating layer, the silver plating layer consisting of a first silver plating layer below the first silver plating layer and a second silver plating layer above the first silver plating layer, with the crystal grain size of the first silver plating layer being larger than the crystal grain size of the second silver plating layer. Patent Document 1 addresses the problem that the crystal grain size of the silver plating layer is likely to increase due to recrystallization, which reduces hardness and wear resistance, by specifying the crystal grain size of the silver plating layer to ensure good wear resistance. However, the size of the crystal grain size depends on the thickness of the plating layer. Therefore, Patent Document 1 imposes restrictions on the thickness of the silver plating layer in order to achieve good wear resistance.

[0004] Patent Document 2 also describes a method for producing a silver-plated product by electroplating a substrate in a silver plating solution containing predetermined concentrations of silver, potassium cyanide, and selenium, where y is the product of the potassium cyanide concentration and the current density in the silver plating solution, and x is the solution temperature, so that y and x satisfy a predetermined relationship. Patent Document 2 exemplifies a method for producing a silver-plated product in which the silver plating film contains elements such as selenium, thereby suppressing an increase in contact resistance while maintaining high hardness. Patent Document 2 uses the Vickers hardness of the silver-plated product surface as the basis for its wear resistance. Thus, Patent Document 2 evaluates the wear resistance of the silver-plated product by measuring the Vickers hardness, which depends on the characteristics of the substrate. However, it is actually necessary to evaluate the wear resistance of the plating film itself, which is less affected by the characteristics of the substrate. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-169408 [Patent Document 2] Patent No. 6611602 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present disclosure is to provide an electrical contact material that has excellent abrasion resistance that is not easily affected by the characteristics of the base material, and a contact, a terminal, and a connector that use the same. [Means for solving the problem]

[0007] [1] An electrical contact material comprising a conductive substrate and a silver-containing layer containing silver provided on at least a part of the surface of the conductive substrate, wherein the average GAM value of the silver-containing layer in a cross section of the electrical contact material is 0.20° or more and 3.00° or less. [2] The electrical contact material according to [1] above, wherein the average crystal grain size in the silver-containing layer is 0.2 μm or more and 2.0 μm or less. [3] The electrical contact material according to the above [1] or [2], wherein the silver-containing layer is a pure silver layer. [4] The electrical contact material according to any one of the above [1] to [3], wherein the average thickness of the silver-containing layer is 0.5 μm or more and 5.0 μm or less. [5] The electrical contact material according to any one of the above [1] to [4], further comprising an intermediate layer made of nickel or a nickel alloy between the conductive substrate and the silver-containing layer. [6] The electrical contact material according to [5] above, wherein the intermediate layer has an average thickness of 0.01 μm or more and 3.00 μm or less. [7] A contact made using the electrical contact material according to any one of the above [1] to [6]. [8] A terminal produced using the electrical contact material according to any one of the above [1] to [6]. [9] A connector produced using the electrical contact material according to any one of the above [1] to [6]. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to provide an electrical contact material that has excellent abrasion resistance and is not easily affected by the characteristics of the base material, as well as a contact, a terminal, and a connector that use the same. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a cross-sectional view showing an example of an electrical contact material according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view showing another example of the electrical contact material according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, a detailed description will be given based on an embodiment.

[0011] As a result of extensive research, the present inventors have focused on the amount of strain in a silver-containing layer provided on at least a part of the surface of a conductive substrate and found that by controlling the GAM value of the silver-containing layer, the abrasion resistance of an electrical contact material is excellent, independent of the properties of the conductive substrate, and have completed the present disclosure based on this finding.

[0012] An electrical contact material according to an embodiment includes a conductive substrate and a silver-containing layer containing silver provided on at least a portion of a surface of the conductive substrate, and the average GAM value of the silver-containing layer in a cross section of the electrical contact material is 0.20° or more and 3.00° or less.

[0013] 1 is a cross-sectional view showing an example of an electrical contact material according to an embodiment. As shown in FIG. 1, the electrical contact material 1 includes a conductive substrate 10 and a silver-containing layer 20.

[0014] The conductive substrate 10 constituting the electrical contact material 1 is a conductive rolled material obtained by rolling. From the viewpoints of the rolling workability of the conductive substrate 10 and the high electrical conductivity of the electrical contact material 1, the conductive substrate 10 is preferably made of a copper-based material including pure copper and copper alloys, or an iron-based material including pure iron and iron alloys. Among these, Cu-Zn-based, Cu-Ni-Si-based, Cu-Sn-Ni-based, Cu-Cr-Mg-based, and Cu-Ni-Si-Zn-Sn-Mg-based copper alloys are preferred.

[0015] The electrical conductivity of the conductive substrate 10 is preferably 60% IACS or more, more preferably 80% IACS or more. When the electrical conductivity of the conductive substrate 10 is 60% IACS or more, the electrical contact material 1 has good electrical conductivity.

[0016] The shape of the conductive substrate 10 may be selected appropriately depending on the application of the electrical contact material 1, but is preferably strip-like, plate-like, rod-like or wire-like.

[0017] The silver-containing layer 20 constituting the electrical contact material 1 is provided on at least a portion of the surface of the conductive substrate 10 and contains silver. The silver-containing layer 20 covering the surface of the conductive substrate 10 is made of pure silver or a silver alloy, and is preferably made of pure silver, i.e., the silver-containing layer 20 is preferably a pure silver layer. From the viewpoints of providing the electrical contact material 1 with excellent abrasion resistance and making the abrasion resistance of the electrical contact material 1 less susceptible to the properties of the conductive substrate 10, the silver-containing layer 20 is preferably formed by plating, i.e., the silver-containing layer 20 is preferably a plated film.

[0018] 1, the average GAM value of the silver-containing layer 20 is 0.20° or more and 3.00° or less. The cross section of the electrical contact material 1 is a cross section parallel to the rolling direction of the conductive substrate 10.

[0019] When the average GAM value of the silver-containing layer 20 in the cross section of the electrical contact material 1 is 0.20° or more, the amount of strain remaining in the silver-containing layer 20 can be maintained high, and the hardness can be increased, thereby improving the wear resistance. Furthermore, when the average GAM value of the silver-containing layer 20 is 3.00° or less, deterioration in bending workability due to excessive strain in the silver-containing layer 20 can be suppressed. From this perspective, the lower limit of the average GAM value of the silver-containing layer 20 in the cross section of the electrical contact material 1 is 0.20° or more, preferably 0.50° or more, and the upper limit is 3.00° or less, preferably 1.50° or less.

[0020] The GAM (Grain Average Misorientation) value is a value obtained by averaging the misorientation between pixels in a crystal grain, and is a value that reflects the amount of strain in the silver-containing layer 20 .

[0021] The GAM value can be obtained from crystal orientation analysis data calculated using analysis software (OIM Analysis, manufactured by TSL Solutions) from crystal orientation data continuously measured using an EBSD detector (OIM5.0 HIKARI, manufactured by TSL Solutions) attached to a high-resolution scanning analytical electron microscope (JSM-7001FA, manufactured by JEOL Ltd.). The measurement target is the surface of the silver-containing layer 20 on a cross-section of the electrical contact material 1 parallel to the rolling direction of the conductive substrate 10, which has been mirror-finished with a cross-section polisher (manufactured by JEOL Ltd.). The measurement magnification is 30,000x. Measurements are performed at intervals of 50 nm or less, and measurement points with a CI value of 0.1 or less analyzed by the analysis software are excluded (noise removal). Boundaries where the misorientation between adjacent pixels is 5.00° or more are considered to be grain boundaries, and the GAM value is obtained. This measurement is performed multiple times (in multiple measurement areas on the same sample) and the average value is calculated to obtain the average GAM value. Thus, the average GAM value is the average value of the GAM values ​​in the measurement area of ​​the silver-containing layer measured at 30,000x magnification.

[0022] The average crystal grain size in the silver-containing layer 20 is preferably 0.2 μm or more, more preferably 0.4 μm or more, and even more preferably 0.6 μm or more. When the average crystal grain size in the silver-containing layer 20 is 0.2 μm or more, the abrasion resistance can be further improved.

[0023] The average crystal grain size in the silver-containing layer 20 is preferably 2.0 μm or less, more preferably 1.5 μm or less, and even more preferably 1.0 μm or less. When the average crystal grain size in the silver-containing layer 20 is 2.0 μm or less, the abrasion resistance can be stably maintained.

[0024] The silver-containing layer 20 may also contain one or more elements (hereinafter also referred to as the second element) selected from the group consisting of Sn, Zn, In, Ni, Cu, Se, Sb, and Co. The presence of the second element in the silver-containing layer 20 can improve the slidability. In particular, from the viewpoint of improving the electrical connectivity of the electrical contact material 1, the silver-containing layer 20 preferably contains less than 15.0 at% in total of one or more elements selected from the group consisting of Sn, Zn, In, Ni, Cu, Se, Sb, and Co. Furthermore, from the viewpoint of efficiently improving the slidability and reducing material costs by adding the second element, the silver-containing layer 20 preferably contains 0.1 at% or more in total of one or more elements selected from the group consisting of Sn, Zn, In, Ni, Cu, Se, Sb, and Co.

[0025] The lower limit of the average thickness of the silver-containing layer 20 is preferably 0.5 μm or more, more preferably 2.0 μm or more, and even more preferably 3.0 μm or more. The upper limit of the average thickness of the silver-containing layer 20 is preferably 5.0 μm or less. When the lower limit of the average thickness of the silver-containing layer 20 is 0.5 μm or more, the excellent abrasion resistance of the electrical contact material 1 can be maintained for a long period of time. When the upper limit of the average thickness of the silver-containing layer 20 is 5.0 μm or less, material costs can be reduced.

[0026] Fig. 2 is a cross-sectional view showing another example of an electrical contact material according to an embodiment. The electrical contact material 2 shown in Fig. 2 has basically the same configuration as the electrical contact material 1 shown in Fig. 1, except that an intermediate layer 30 is added.

[0027] 2, the electrical contact material 2 further includes an intermediate layer 30 made of nickel or a nickel alloy between the conductive substrate 10 and the silver-containing layer 20. When the intermediate layer 30 is provided between the surface of the conductive substrate 10 and the silver-containing layer 20, thermal diffusion of the elements constituting the conductive substrate 10 into the silver-containing layer 20 can be suppressed and the adhesion between the conductive substrate 10 and the silver-containing layer 20 can be improved.

[0028] From the viewpoint of suppressing the thermal diffusion and further improving the adhesion, the intermediate layer 30 is preferably made of pure nickel or a Ni-P based nickel alloy.

[0029] The lower limit of the average thickness of the intermediate layer 30 is preferably 0.01 μm or more, more preferably 0.10 μm or more, and even more preferably 0.30 μm or more. The upper limit of the average thickness of the intermediate layer 30 is preferably 3.00 μm or less, more preferably 2.00 μm or less, and even more preferably 1.00 μm or less. If the lower limit of the average thickness of the intermediate layer 30 is less than 0.01 μm, the above-mentioned suppression of thermal diffusion and improvement of adhesion cannot be achieved. If the upper limit of the average thickness of the intermediate layer 30 exceeds 3.00 μm, bending workability deteriorates. When the electrical contact material is used in a terminal, bending workability of R / t≧1 is required.

[0030] Furthermore, the above-described electrical contact materials 1 and 2 may further include a copper layer (not shown) directly below the silver-containing layer 20, which is the surface layer. The copper layer (not shown) is made of pure copper or a copper alloy. The thickness of the copper layer (not shown) is significantly smaller than the thickness of the conductive substrate 10. When the electrical contact materials 1 and 2 further include a copper layer (not shown) directly below the silver-containing layer 20, the adhesion and bending workability can be improved.

[0031] As described above, the electrical contact materials 1 and 2 have excellent abrasion resistance that is not easily affected by the properties of the conductive substrate 10, and therefore the electrical contact materials 1 and 2 can be suitably used for contacts, terminals, and connectors. Such contacts are contacts made using the electrical contact materials 1 and 2, the terminals are terminals made using the electrical contact materials 1 and 2, and the connectors are connectors made using the electrical contact materials 1 and 2.

[0032] Next, a method for producing the electrical contact materials 1 and 2 will be described.

[0033] First, a silver-containing layer is formed on at least a portion of the surface of a conductive substrate by plating or the like. Then, the substrate having the silver-containing layer on its surface is rolled. In this way, the electrical contact material 1 can be produced.

[0034] An intermediate layer is formed on at least a portion of the surface of the conductive substrate by plating or the like. Then, a silver-containing layer is formed on the intermediate layer by plating or the like. Then, the substrate including the intermediate layer and the silver-containing layer is rolled. In this manner, the electrical contact material 2 can be produced.

[0035] Regarding the plating conditions for the silver-containing layer, the current density was set at 5A / dm 2 More than 10A / dm 2 Hereinafter, by setting the bath temperature (liquid temperature) to 25°C or higher and prioritizing nucleation, a large number of crystal grains with different crystal orientations grow, and the difference in crystal orientation becomes greater, thereby further increasing the internal stress of the silver-containing layer.

[0036] The rolling processing ratio is 20% or more and 40% or less. When the rolling processing ratio is 20% or more, the amount of strain in the silver-containing layer is increased, thereby improving wear resistance. When the rolling processing ratio is 40% or less, deterioration of bending workability due to excessive strain in the silver-containing layer can be suppressed. The rolling processing ratio is the percentage obtained by dividing the difference between the cross-sectional area of ​​the sample before rolling and the cross-sectional area of ​​the sample after rolling by the cross-sectional area of ​​the sample before rolling.

[0037] After the silver-containing layer is formed and before the rolling process, a heat treatment may be performed at 300°C to 600°C for 5 to 60 seconds. This heat treatment can homogenize the strain introduced by plating.

[0038] When manufacturing the electrical contact materials 1 and 2 having the silver-containing layer 20 containing the second element, the silver-containing layer containing the second element may be directly formed by, for example, a plating method using a plating bath containing a silver component and a second element component, as described above. Alternatively, the silver-containing layer containing the second element may be formed by alternately depositing silver-containing layers and second-element layers by, for example, a plating method, followed by a heat treatment. In this case, the rolling rate is preferably 20% or more and 40% or less, from the same viewpoint as above.

[0039] According to the embodiment described above, by focusing on the amount of strain in the silver-containing layer provided on the surface of the conductive substrate and controlling the GAM value of the silver-containing layer, it is possible to obtain an electrical contact material that has excellent abrasion resistance that is less susceptible to the effects of substrate characteristics.

[0040] Although the embodiments have been described above, the present invention is not limited to the above embodiments, but includes all aspects encompassed by the concept and scope of the claims of the present disclosure, and can be modified in various ways within the scope of the present disclosure. [Example]

[0041] Next, examples and comparative examples will be described, but the present disclosure is not limited to these examples.

[0042] Examples 1 to 5 The substrate (Furukawa Electric, EFTEC-550T, 80% IACS) was subjected to electrolytic degreasing and then acid cleaning. After that, a silver-containing layer was plated (current density 10 A / dm) in an alkaline cyanide silver bath (silver cyanide 50 g / L, potassium cyanide 100 g / L) at a bath temperature of 25°C. 2 ) was formed on the surface of the substrate, followed by rolling at the working ratio shown in Table 1, to produce electrical contact materials having the silver-containing layer (pure silver layer) shown in Table 1.

[0043] (Examples 6 to 10, Comparative Examples 1 to 3) The substrate (Furukawa Electric, EFTEC-550T, 80% IACS) was subjected to electrolytic degreasing and then acid cleaning. After that, the intermediate layer was plated (current density 15 A / dm) in a nickel plating bath (nickel sulfate hexahydrate 500 g / L, nickel chloride 30 g / L, boric acid 30 g / L) at a bath temperature of 55°C. 2 ) on the surface of the substrate, and then a silver-containing layer was plated (current density 10 A / dm) in an alkaline cyanide silver bath (silver cyanide 50 g / L, potassium cyanide 100 g / L) at a bath temperature of 25°C. 2) was formed on the surface of the intermediate layer, followed by rolling at the working ratio shown in Table 1, thereby producing electrical contact materials having a silver-containing layer (pure silver layer) and an intermediate layer (pure nickel layer) shown in Table 1. In Comparative Example 3, rolling was not performed.

[0044] Examples 11 to 13 The substrate (Furukawa Electric, EFTEC-550T, 80% IACS) was subjected to electrolytic degreasing and then acid cleaning. After that, the intermediate layer was plated (current density 10 A / dm) in a nickel-phosphorus electrolytic bath (nickel sulfate hexahydrate 500 g / L, nickel chloride hexahydrate 30 g / L, boric acid 30 g / L, phosphorous acid 16 g / L) at a bath temperature of 55°C. 2 ) on the surface of the substrate, and then a silver-containing layer containing a second element is plated (current density 5-10 A / dm) in an alkaline cyanide silver bath (silver cyanide 50-100 g / L, potassium cyanide 100-200 g / L, indium trichloride 15 g / L) at a bath temperature of 25°C. 2 ) on the surface of the intermediate layer, followed by rolling at the working ratio shown in Table 1, to produce electrical contact materials having a silver-containing layer (silver alloy layer) and an intermediate layer (nickel alloy layer) shown in Table 1.

[0045] (Examples 14 to 34) The substrate (Furukawa Electric, EFTEC-550T, 80% IACS) was subjected to electrolytic degreasing and then acid cleaning. After that, the intermediate layer was plated (current density 15 A / dm) in a nickel plating bath (nickel sulfate hexahydrate 500 g / L, nickel chloride 30 g / L, boric acid 30 g / L) at a bath temperature of 55°C. 2 ), and then a silver-containing layer containing a second element was plated (current density 5 to 10 A / dm) in an alkaline cyanide silver bath (silver cyanide 50 to 100 g / L, potassium cyanide 100 to 200 g / L, zinc chloride 10 g / L (Examples 14 to 16), nickel chloride 10 g / L (Examples 17 to 22), copper chloride dihydrate 12 g / L (Examples 20 to 22), potassium selenocyanate 2.2 mg / L (Examples 23 to 25), antimony trichloride 12 g / L (Examples 26 to 28), cobalt chloride 10 g / L (Examples 29 to 31), tin (II) chloride dihydrate 15 g / L (Examples 32 to 34)) at a bath temperature of 25°C.2 ) on the surface of the intermediate layer, followed by rolling at the working ratio shown in Table 1, to produce electrical contact materials having a silver-containing layer (silver alloy layer) and an intermediate layer (pure nickel layer) shown in Table 1.

[0046] (Comparative Examples 4 to 9) The substrate (Furukawa Electric, EFTEC-550T, 80% IACS) was subjected to electrolytic degreasing and then acid cleaning. After that, the intermediate layer was plated (current density 15 A / dm) in a nickel plating bath (nickel sulfate hexahydrate 500 g / L, nickel chloride 30 g / L, boric acid 30 g / L) at a bath temperature of 55°C. 2 ) on the surface of the substrate, and then a silver-containing layer containing the second element is plated (current density 5-10 A / dm) in an alkaline cyanide silver bath (silver cyanide 50-100 g / L, potassium cyanide 100-200 g / L, tin (II) chloride dihydrate 15 g / L) at a bath temperature of 25°C. 2 ) on the surface of the intermediate layer, followed by rolling at the working ratio shown in Table 1, to produce electrical contact materials having a silver-containing layer (silver alloy layer) and an intermediate layer (pure nickel layer) shown in Table 1. In Comparative Example 8, no intermediate layer was formed.

[0047] [Measurement and Evaluation] The electrical contact materials obtained in the above examples and comparative examples were subjected to the following measurements and evaluations. The results are shown in Table 2.

[0048] [1] Average GAM value The GAM value was obtained from crystal orientation analysis data calculated using analysis software (TSL Solutions, OIM Analysis) from crystal orientation data continuously measured using an EBSD detector (TSL Solutions, OIM5.0 HIKARI) attached to a high-resolution scanning analytical electron microscope (JEOL Ltd., JSM-7001FA).

[0049] Using a cross-section polisher (manufactured by JEOL Ltd.), the silver-containing layer surface was obtained from a mirror-finished cross section of the electrical contact material parallel to the rolling direction of the conductive substrate. The measurement magnification was 30,000x. Measurements were performed at intervals of 50 nm or less. Measurement points with a CI value of 0.1 or less as analyzed by the analysis software were excluded, and boundaries with an orientation difference of 5.00° or more between adjacent pixels were considered to be grain boundaries, and the GAM value was obtained. This measurement was performed five times (at five different measurement areas on the same sample) and the average value was calculated to obtain the average GAM value of the silver-containing layer.

[0050] [2] Average grain size A cross section of the electrical contact material parallel to the rolling direction of the conductive substrate was mirror-finished with a cross-section polisher (manufactured by JEOL Ltd.), and the silver-containing layer surface on the surface was observed at a magnification of 30,000 times in an SEM image, and the average crystal grain size in the silver-containing layer was obtained by a cutting method using a line segment perpendicular to the plating thickness direction.

[0051] [3] Coefficient of kinetic friction An electrical contact material was subjected to bulging processing to obtain an bulged material with a 5 mm radius of curvature of the bulged portion. The surface of the silver-containing layer side of the bulged material was subjected to 15 reciprocating sliding tests using a Tribogear friction and wear tester (surface property measuring instrument TYPE: 14FW, manufactured by Shinto Scientific Co., Ltd.) at a contact load of 5 N, a sliding distance of 5 mm, and a sliding speed of 100 mm / min. The value after the 15th sliding test was taken as the dynamic friction coefficient. The dynamic friction coefficient was ranked as follows:

[0052] ◎: Coefficient of dynamic friction is less than 0.4 ○: Coefficient of dynamic friction is 0.4 or more and less than 0.6 ×: Dynamic friction coefficient is 0.6 or more

[0053] [4] Abrasion resistance The surface of the silver-containing layer of the electrical contact material was subjected to 50 reciprocating strokes using a friction and wear tester, Tribogear (surface property measuring instrument Type: 14FW, manufactured by Shinto Scientific Co., Ltd.), with a contact load of 4 N, a sliding distance of 50 mm, and a sliding speed of 100 mm / min. A laser roughness tester was used to measure the ratio of the depth from the reference surface (the surface that was not subjected to reciprocating sliding) to the thickness of the silver-containing layer. The wear resistance was ranked as follows:

[0054] ◎: The ratio of the depth from the reference plane to the thickness of the silver-containing layer is less than 1 / 20 ○: The ratio of the depth from the reference plane to the thickness of the silver-containing layer is 1 / 20 or more and less than 1 / 10 ×: The ratio of the depth from the reference plane to the thickness of the silver-containing layer is 1 / 10 or more

[0055] [5] Contact resistance The contact resistance of the surface of the silver-containing layer of the electrical contact material was measured 10 times using an electrical contact simulator (manufactured by Yamazaki Seiki Kenkyusho Co., Ltd.) at a current of 20 mA and a load of 1 N, and the average of the measured values ​​was taken as the contact resistance of the electrical contact material. The contact resistance was ranked as follows:

[0056] ◎: Contact resistance is less than 0.5mΩ ○: Contact resistance is 0.5 mΩ or more and less than 1.0 mΩ ×: Contact resistance is 1.0 mΩ or more

[0057] [6] Heat resistance The electrical contact materials were heated in an air atmosphere at 150°C for 1000 hours. After heating, the contact resistance of the silver-containing layer side of the electrical contact material was measured 10 times using an electrical contact simulator (manufactured by Yamazaki Seiki Kenkyusho Co., Ltd.) at a current of 20 mA and a load of 1 N, and the average of the measured values ​​was used as the contact resistance of the electrical contact material. Heat resistance was ranked as follows:

[0058] ◎: Contact resistance after heating is less than 1.0 mΩ ○: Contact resistance after heating is 1.0 mΩ or more and less than 5.0 mΩ ×: Contact resistance after heating is 5.0 mΩ or more

[0059] [7] Bending workability In accordance with the test method of the Japan Copper and Brass Association technical standard JCBA-T307:2007, five test pieces (n=5) measuring 10 mm in width and 30 mm in length were taken from the electrical contact material so that the longitudinal direction of the test piece was parallel to the rolling direction, and a bending test was performed on each test piece at a bending angle of 90 degrees and R / t=1 to determine the presence or absence of cracks.

[0060] ○: No cracks in the five test pieces ×: One or more test pieces were cracked

[0061] [Table 1]

[0062] [Table 2]

[0063] As shown in Tables 1 and 2, in Examples 1 to 34, the average GAM value of the silver-containing layer was 0.20° or more and 3.00° or less, and therefore the abrasion resistance of the electrical contact materials was good and not affected by the properties of the conductive substrate. On the other hand, in Comparative Examples 1 to 9, the average GAM value of the silver-containing layer was outside the range of 0.20° or more and 3.00° or less, and therefore the abrasion resistance of the electrical contact materials was poor. [Explanation of symbols]

[0064] 1, 2 Electrical contact materials 10 Conductive base material 20 Silver-containing layer 30 Middle Class

Claims

1. A conductive substrate; a silver-containing layer containing silver provided on at least a portion of the surface of the conductive substrate; An electrical contact material comprising: An electrical contact material, wherein the average GAM value of the silver-containing layer in a cross section of the electrical contact material is 0.20° or more and 3.00° or less.

2. 2. The electrical contact material according to claim 1, wherein the average crystal grain size in said silver-containing layer is 0.2 μm or more and 2.0 μm or less.

3. 3. The electrical contact material according to claim 1, wherein the silver-containing layer is a pure silver layer.

4. 4. The electrical contact material according to claim 1, wherein the average thickness of the silver-containing layer is 0.5 μm or more and 5.0 μm or less.

5. 5. The electrical contact material according to claim 1, further comprising an intermediate layer made of nickel or a nickel alloy between the conductive substrate and the silver-containing layer.

6. 6. The electrical contact material according to claim 5, wherein the average thickness of the intermediate layer is 0.01 μm or more and 3.00 μm or less.

7. A contact made using the electrical contact material according to any one of claims 1 to 6.

8. A terminal made using the electrical contact material according to any one of claims 1 to 6.

9. A connector produced using the electrical contact material according to any one of claims 1 to 6.

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