Silver alloy clad structure of charging terminal and its manufacturing method

Abstract

A layered structure for forming a charging terminal for high-power applications. In some embodiments, the layered structure can include a substrate and a contact layer disposed on at least a portion of the substrate. The substrate can have a conductivity greater than 40% International Annealed Copper Standard (IACS). The contact layer can exhibit a coefficient of friction less than 1.4, e.g., 0.1 to 1.4, as measured in accordance with American Society for Testing and Materials (ASTM) G99-17. The contact layer can include a precious metal-based alloy, e.g., a silver-samarium alloy.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Patent Application No. 62 / 966,821, filed January 28, 2020, which is incorporated herein by reference.

[0002] This disclosure relates to materials and structures having a low coefficient of friction, low electrical resistance, and high wear / abrasion resistance. In particular, this disclosure relates to structures used as charging terminals for high power applications that exhibit improved performance characteristics. [Background technology]

[0003]

[0003] Battery-powered products require charging. Effective charging, especially for high-power products, requires ever-increasing current / voltage loads, as well as improved electrical conductivity and minimized resistive losses at the charging terminals. Higher charging rates and resulting shorter charging times enable next-generation fast charging systems to increase current levels from the traditional 10 A to 30 A up to 500 A or even 1,000 A.

[0004]

[0004] A typical electrical terminal often includes a conductive substrate and a contact layer. The conductive substrate provides power transfer, and the contact layer, e.g., silver metal, reduces surface contact resistance when power is transferred from the plug end of the charging terminal and received at the receptacle end of the charging terminal. However, these coated terminals often suffer from issues related to coefficient of friction, durability, and insertion force. In some applications, such as electric vehicle terminals, the market demands charging cycles that can extend to thousands of insertion / withdrawal cycles. This, combined with the physical constraints of the allowable insertion force when the plug end of the charging terminal is inserted into the receptacle end, creates unique challenges. This is further complicated by the fact that the surface of the charging terminal wears over time, degrading the electrical contact of the charging terminal.

[0005]

[0005] It has been found that conventional charging terminal materials, such as copper substrates with electroplated (pure) silver contact layers, produced using conventional methods are unable to produce charging terminal contacts that meet these ever-increasing requirements.

[0006]

[0006] In view of known products, there remains a need for effective structures, such as charging terminals, that exhibit improved electrical conductivity and low resistance while exhibiting improved coefficient of friction, durability and / or insertion force. Summary of the Invention [Means for solving the problem]

[0007] In some embodiments, the present disclosure provides a copper alloy having a copper content of greater than 40% International Annealed Copper Standard (IACS) (or 3.4801×10 7The present invention relates to a layered structure including a substrate having a conductivity greater than 60% IACS (S / m), for example, greater than 60% IACS, and a contact layer disposed on at least a portion of the substrate. The contact layer exhibits a coefficient of friction less than 1.4. The coefficient of friction is measured in accordance with American Society for Testing and Materials (ASTM) G99-17. In some embodiments, the contact layer comprises a rare earth metal. In some embodiments, the contact layer comprises samarium. In some embodiments, the contact layer comprises a precious metal-based alloy. In some embodiments, the contact layer comprises a silver alloy. In some embodiments, the contact layer comprises a samarium-silver alloy. In some embodiments, the contact layer comprises samarium oxide. In some embodiments, the contact layer comprises less than 0.1 wt% samarium oxide. In some embodiments, the contact layer comprises less than 0.2 vol% samarium oxide. In some embodiments, the contact layer comprises samarium oxide distributed throughout a depth of the contact layer ranging from 0.001 μm to 50 μm, as measured from the surface of the contact layer. In some embodiments, the contact layer comprises copper, nickel, or zinc, or a combination thereof. In some embodiments, the contact layer comprises 0.001 wt% to 10 wt% samarium; and / or 50 wt% to 99.9 wt% silver. In some embodiments, the contact layer comprises 0.001 wt% to 10 wt% samarium; and / or the balance silver. In some embodiments, the contact layer comprises 50 wt% to 99.9 wt% silver; 0.1 wt% to 20 wt% nickel; 1 wt% to 30 wt% copper; and 0.001 wt% to 10 wt% zinc. In some embodiments, the substrate comprises a metal, preferably copper or a copper alloy.

[0008] In some embodiments, the contact layer exhibits a coefficient of friction in the range of 0.1 to 1.4. In some embodiments, the contact layer exhibits a coefficient of friction greater than 80% IACS (or 4.6401 x 10 7 In some embodiments, the contact layer exhibits a conductivity of greater than 86% IACS (or 4.9881×10 7In some embodiments, the contact layer exhibits a hardness greater than 80 HV as measured by ASTM E384-17. In some embodiments, the contact layer exhibits a hardness in the range of 25 HV to 100 HV. In some embodiments, the contact layer exhibits a hardness in the range of 150 HV to 200 HV. In some embodiments, the substrate exhibits a conductivity greater than 95% IACS (or 5.5101 x 10 7 In some embodiments, the substrate exhibits a yield strength of less than 70 ksi as measured by ASTM E8 / or E8M-16a. In some embodiments, the layered structure exhibits a conductivity of greater than 80% IACS (or 4.6401×10 7 It exhibits a conductivity of over 1000 S / m.

[0009] In some embodiments, the contact layer has a thickness in the range of 5 μm to 40 μm. In some embodiments, the layered structure has a thickness in the range of 0.1 mm to 5 mm. In some embodiments, the layered structure is formed by cladding the contact layer onto a substrate. In some embodiments, the layered structure further includes a diffusion barrier disposed between the substrate and the contact layer. In some embodiments, the diffusion barrier includes nickel or niobium. In some embodiments, the diffusion barrier has a thickness in the range of 0.01 mm to 0.05 mm. In some embodiments, the layered structure further includes a backing layer disposed on at least a portion of the substrate opposite the contact layer. In some embodiments, the backing layer includes a high-strength copper-based alloy or an iron-based alloy. In some embodiments, the backing layer includes steel. In some embodiments, the backing layer has a thickness in the range of 0.1 mm to 1 mm. In some embodiments, the substrate and / or the contact layer are substantially flat. In some embodiments, the substrate is cylindrical, and the contact layer is disposed around at least a portion of the outer surface of the cylindrical substrate. In some embodiments, the layered structure is configured for high-power applications.

[0010] In some embodiments, the present disclosure relates to an electrical terminal or connector made from a layered structure. The electrical terminal or connector is configured to undergo more than 5,000 insertion and extraction cycles without failure. In some embodiments, the electrical terminal or connector experiences an increase in contact resistance of less than 30%, less than 15%, less than 10%, less than 5%, less than 3%, less than 2%, or less than 1% when subjected to at least 5,000 insertion and extraction cycles.

[0011] In some embodiments, the present disclosure provides a method for treating a pulmonary artery disease (PAGE) with a PAGE of greater than 60% IACS (or 3.4801×10 7 and a contact layer disposed on at least a portion of the substrate. The charging terminal exhibits a coefficient of friction in the range of 0.1 to 1.4, as measured in accordance with ASTM G99-17.

[0012] In some embodiments, the present disclosure relates to a contact layer composition comprising samarium; silver; nickel; copper; and / or zinc. The contact layer composition exhibits a coefficient of friction in the range of 0.1 to 1.4 as measured according to ASTM G99-17. In some embodiments, the contact layer composition comprises 0.001 wt% to 10 wt% samarium; and / or 50 wt% to 99.9 wt% silver. In some embodiments, the contact layer composition comprises 50 wt% to 99.9 wt% silver; 0.1 wt% to 20 wt% nickel; 1 wt% to 30 wt% copper; and 0.001 wt% to 10 wt% zinc. In some embodiments, the contact layer exhibits a coefficient of friction greater than 86% IACS (or 4.9881 x 10 7 In some embodiments, the samarium is samarium oxide.

[0013] In some embodiments, the present disclosure relates to a method for preparing the layered structure described herein. The method includes providing a substrate; and forming a contact layer on the substrate. In some embodiments, forming the contact layer on the substrate includes forming an alloy including samarium metal on the substrate. In some embodiments, forming the contact layer on the substrate further includes oxidizing at least a portion of the samarium metal by exposing the contact layer to air. In some embodiments, the method further includes forming a diffusion barrier between the substrate and the contact layer, optionally including nickel or niobium. In some embodiments, the method further includes forming a backing layer between the substrate and the contact layer, optionally including a high-strength copper or iron-based alloy. In some embodiments, any of the contact layer, diffusion barrier, and / or backing layer is obtained by cladding.

[0014] A further understanding of the nature and advantages of the techniques of the present disclosure may be realized by reference to the remaining portions of the specification and the drawings. [Brief explanation of the drawings]

[0015] [Figure 1]

[0015] FIG. 1 is a diagrammatic representation of an embodiment of a layered structure that may be used to form or manufacture a charging terminal or contact. [Figure 2]

[0016] FIG. 10 is a diagrammatic representation of another embodiment of a layered structure that may be used to form or manufacture a charging terminal or contact. [Figure 3]

[0017] FIG. 10 is a diagrammatic representation of another embodiment of a layered structure that may be used to form or manufacture a charging terminal or contact. [Figure 4]

[0018] FIG. 10 is a diagrammatic representation of another embodiment of a layered structure that may be used to form or manufacture a charging terminal or contact. [Figure 5]

[0019] FIG. 10 is a diagrammatic representation of another embodiment of a layered structure that may be used to form or manufacture a charging terminal or contact. [Figure 6]

[0020] FIG. 10 is a diagrammatic representation of another embodiment of a layered structure that may be used to form or manufacture a charging terminal or contact. [Figure 7]

[0021] FIG. 1 is a diagrammatic representation of an embodiment of a cladding method. [Figure 8A]

[0022] FIG. 10 is a diagrammatic representation of another embodiment of the cladding method. [Figure 8B]

[0023] FIG. 10 shows a schematic diagram of further details of an embodiment of the cladding method. [Figure 9A]

[0024] FIG. 10 is a diagrammatic representation of another embodiment of a layered structure that may be used to form or manufacture a charging terminal or contact. [Figure 9B]

[0025] 9B is a schematic diagram illustrating an embodiment of the plug end of a charging terminal manufactured using the layered structure shown in FIG. 9A. FIG. [Figure 9C]

[0026] 9B is a diagrammatic representation of an embodiment of a receptacle end of a charging terminal manufactured using the layered structure shown in FIG. 9A. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0016] overview

[0027] As previously discussed, conventional charging terminal materials manufactured using conventional methods have been unable to meet the increasing mechanical and electrical performance requirements demanded by evolving high-power products, such as electric vehicles. In particular, there is a need for structures that exhibit improved electrical conductivity and low resistance while also exhibiting improved coefficient of friction, durability, and / or insertion force.

[0017]

[0028] The present inventors have now discovered that when certain rare earth metals are added to a precious metal-based contact layer to establish and / or improve contact between electrical terminals, they can help improve the performance of the electrical terminal, such as, among other things, the coefficient of friction, hardness, and / or wear. In some cases, the addition of certain rare earth metals, such as samarium, to the contact layer material has been found to reduce frictional forces during insertion and / or removal of the charging terminal. These improvements were demonstrated without significantly affecting charging performance, such as electrical conductivity. Typically, the addition of other alloying elements, such as alloying elements other than rare earth metals, significantly impairs electrical conductivity, requiring significant weight percent additions for effective hardening to improve wear resistance. Without being bound by theory, the addition of rare earth metals, such as samarium, to certain precious metal-based alloys, such as silver alloys, produces a smooth surface oxide on the alloy surface, reducing the coefficient of friction of the alloy while maintaining acceptable electrical conductivity. This unexpected result can be applied to meet the stringent requirements of electric vehicle charging, which requires extremely high life cycles. For example, a charging terminal in an electric vehicle may undergo thousands of insertions and removals. Given the low coefficient of friction provided by the contact layers described herein, the charging terminal will not suffer significant loss of electrical performance, such as loss of efficient electrical contact (or low contact resistance), due to excessive wear throughout its operational life.

[0018]

[0029] In some embodiments, the present disclosure relates to a layered structure (for use in a charging terminal). The layered structure may include a substrate and a precious metal-based alloy with an added rare earth metal forming a contact layer on at least a portion of the substrate. In some embodiments, the rare earth metal contained in the contact layer may include any one of lanthanides, scandium, or yttrium, or a combination thereof. In some embodiments, the rare earth metal contained in the contact layer may include samarium. In some embodiments, the contact layer may include a precious metal-based contact layer and may include silver. Thus, the contact layer may be referred to as a samarium-silver alloy. In some embodiments, the contact layer may further optionally include copper, zinc, or a combination thereof. The addition of copper, nickel, and / or zinc may improve the hardness of the precious metal-based alloy.

[0019]

[0030] The composition of the contact layer provides the excellent surface properties discussed herein, such as contact resistance, abrasion / wear resistance, and / or coefficient of friction. In particular, the surface properties of the contact layer have been found to unexpectedly reduce insertion force while improving the abrasion resistance and electrical resistance loss of charging contacts of charging terminals, such as plugs and / or receptacles. Such performance is particularly beneficial in applications related to electric vehicles (EVs) and / or plug-in hybrid electric vehicles (PHEVs). The contact layer can be formed / applied by various methods, such as cladding, electroplating, etc. The layer is not limited by the method by which it is formed.

[0020] Substrate characteristics

[0031] The substrate has electrical (conductive) and mechanical properties and works synergistically with the contact layer to surprisingly improve the overall performance of the charging terminal, both electrically and mechanically. In some embodiments, the substrate may be made of a conductor, such as a metal or metal alloy, more specifically copper or a copper alloy, for conducting current through the charging terminal. In some embodiments, the substrate may have a relatively high conductivity as required by fast charging requirements for high-power applications. In some embodiments, the substrate may have a conductivity greater than 40% International Annealed Copper Standard (IACS), for example, greater than 60% IACS. IACS is used herein as a comparative property for defining the conductivity of various materials described herein and is not limited to the conductivity of copper. For example, in the description, the conductivity of a material may be defined as 85% IACS, meaning that the electrical conductivity of a particular material is 85% of that of pure copper as defined by IACS. The conductivity of pure copper as defined by IACS, i.e., 100% IACS, is 5.8001×10 7 It is measured in siemens per meter (S / m). Therefore, the conductivity of 85% IACS is 85% x 5.8001 x 10 7 S / m=4.9301×10 7 S / m.

[0021]

[0032] In low power and / or low current carrying applications, the electrical conductivity of the substrate metal is of less functional importance. Substrate selection based on electrical conductivity is less important than mechanical stiffness and spring properties. Thus, a wide range of substrate alloys with high stiffness and spring properties but correspondingly low electrical conductivity may be suitable, and indeed desirable, for these smaller profile delicate connections. It is well known that elemental additions are employed to produce high strength copper alloys. However, these additions can adversely affect electrical conductivity, for example, below 60% IACS (or 3.4801 x 10 7This results in substrates with low electrical conductivity (less than 1000 kJ / m). Also, modification of these low-conductivity substrates to improve conductivity adversely affects the required resilience, rendering the resulting product unsuitable. In other words, a certain degree of resilience (required for some low-power and / or more delicate applications) conflicts with the ability to conduct electricity at high power levels. Thus, materials suitable for low-power applications may be limited to low power and suitable only for these delicate, yet mechanically demanding, applications.

[0022]

[0033] In some cases, when the substrate is a copper-based substrate, to obtain high stiffness, high strength, and spring properties, suitable materials for forming the substrate may have a relatively high weight percent alloying element (e.g., an element other than copper) or a relatively low copper content, e.g., less than 40% copper. This is because a relatively high copper content, e.g., greater than 40% copper, greater than 50% copper, greater than 60% copper, greater than 70% copper, greater than 80% copper, greater than 90% copper, greater than 95% copper, or approaching 100% copper, produces a relatively flexible substrate. The addition of alloying elements can increase hardness, stiffness, and / or strength, but can also significantly decrease the electrical conductivity of the substrate. As noted above, when materials are modified to obtain resiliency by adding alloying elements, such modifications may still result in low electrical conductivity, e.g., less than 60% IACS (or 3.4801×10 7 S / m), which may make the material unsuitable for high power applications.

[0023]

[0034] In various embodiments described herein, the substrate is 40% IACS (2.3200×10 7 S / m) ~ 100% IACS (5.8001 x 10 7 S / m), e.g., 45% IACS (2.6100 × 10 7 S / m) ~ 100% IACS (5.8001 x 10 7 S / m), 50% IACS (2.9000 × 10 7 S / m) ~ 100% IACS (5.8001 x 10 7 S / m), 55% IACS (3.1900 × 10 7S / m) ~ 100% IACS (5.8001 x 10 7 S / m), 60% IACS (3.4801 × 10 7 S / m) ~ 100% IACS (5.8001 x 10 7 S / m), 65% IACS (3.7701 × 10 7 S / m) ~ 100% IACS (5.8001 x 10 7 S / m), 70% IACS (4.0601 × 10 7 S / m) ~ 100% IACS (5.8001 x 10 7 S / m, 75% IACS (4.3501 × 10 7 S / m) ~ 100% IACS (5.8001 x 10 7 S / m), 80% IACS (4.6401 × 10 7 S / m) ~ 100% IACS (5.8001 x 10 7 S / m), 85% IACS (4.9301 × 10 7 S / m) ~ 100% IACS (5.8001 x 10 7 S / m), 90% IACS (5.2201 × 10 7 S / m) ~ 100% IACS (5.8001 x 10 7 S / m), or 95% IACS (5.5101 x 10 7 S / m) ~ 100% IACS (5.8001 x 10 7 On the lower end, the substrate may have a conductivity in the range of 40% IACS (2.3200 x 10 S / m). 7 S / m), e.g., 45% IACS (2.6100 × 10 7 S / m), 50% IACS (2.9000 x 10 7 S / m), 55% IACS (3.1900 × 10 7 S / m), over 60%IACS (3.4801 x 10 7 S / m), e.g., 65% IACS (3.7701 × 10 7 S / m), 70% IACS (4.0601 × 10 7 S / m), 75% IACS (4.3501 × 10 7 S / m), over 80% IACS (4.6401 × 10 7 S / m), 85% IACS (4.9301 × 10 7S / m), 90% IACS (5.2201 × 10 7 S / m), 91% IACS (5.2781 × 10 7 S / m), 92% IACS (5.3361 × 10 7 S / m), 93% IACS (5.3941 × 10 7 S / m), 94% IACS (5.4521 × 10 7 S / m), 95% IACS (5.5101 × 10 7 S / m), 96% IACS (5.5681 × 10 7 S / m), 97% IACS (5.6261 × 10 7 S / m), 98% IACS (5.6841 × 10 7 S / m), 99% IACS (5.7421 x 10 7 The conductivity may be greater than or equal to 1000 psi (S / m).

[0024]

[0035] In some embodiments, the substrates described herein exhibit a yield strength in the range of 5 ksi to 70 ksi, e.g., 6 ksi to 70 ksi, 8 ksi to 70 ksi, 10 ksi to 60 ksi, 20 ksi to 50 ksi, or 30 ksi to 40 ksi, as measured according to ASTM E8 / E8M-16a. On the lower end, the substrate may exhibit a yield strength of greater than 5 ksi, e.g., greater than 6 ksi, 8 ksi, 10 ksi, 20 ksi, 30 ksi, 40 ksi, 50 ksi, 60 ksi, or greater than 65 ksi. On the upper end, the substrate may exhibit a yield strength of less than 70 ksi, e.g., less than 60 ksi, less than 50 ksi, less than 40 ksi, less than 30 ksi, less than 20 ksi, less than 10 ksi, less than 8 ksi, or less than 6 ksi.

[0025]

[0036] In contrast, low conductivity (e.g., 60% IACS (or 3.4801 x 10 7 For applications requiring high strength at the expense of lower S / m), particularly relatively low power applications, copper-based substrates for these applications may exhibit yield strengths greater than 70 ksi and may range from 70 ksi to 120 ksi.

[0026] Effect of rare earth metal addition

[0037] As discussed above, the addition of rare earth metals allows the contact layer to achieve a very low coefficient of friction, thereby reducing the insertion force of the resulting charging terminal. Without being bound by theory, it is believed that the low coefficient of friction may be the result of one or more smooth oxides that may develop from one or more of the metals contained in the contact layer. In some embodiments, the oxides may include oxides that develop from the rare earth metals contained in the contact layer when the contact layer is exposed to air. In some embodiments, the one or more developed oxides may include samarium oxide. In some embodiments, the one or more developed oxides may further include samarium(III) oxide. In some embodiments, other metals contained in the contact layer, such as silver, nickel, copper, zinc, etc., may also form one or more oxides on the surface of the substrate. It is believed that the unique and unexpected properties of rare earth metal oxides, such as samarium oxide, impart a low-friction effect to the surface of the silver alloy matrix.

[0027]

[0038] It is believed that the oxide may form a surface layer of the contact layer or may be present only on the surface of the contact layer, while the metal below the surface may remain elemental metal until it is exposed to air due to abrasion / erosion, etc., and then oxidized. Thus, over the operational life of the charging terminal, the contact layer may exhibit excellent electrical conductivity because the composition of the contact layer remains primarily elemental metal, and the exposed surface of the contact layer may exhibit a very low coefficient of friction due to the oxide that develops, allowing for convenient insertion and / or removal of the charging terminal.

[0028] Composition wt%

[0039] In some embodiments, the rare earth metal, e.g., samarium, may be present in the contact layer in an amount (significantly) less than the amount of the noble metal, e.g., silver. In some embodiments, the contact layer may include 0.001 wt% to 10 wt%, e.g., 0.1 wt% to 9 wt%, 1 wt% to 8 wt%, 2 wt% to 7 wt%, 3 wt% to 6 wt%, or 4 wt% to 5 wt% of the rare earth metal, based on the total weight of the contact layer. In terms of lower limits, the contact layer may include more than 0.001 wt%, e.g., more than 0.005 wt%, more than 0.01 wt%, more than 0.05 wt%, more than 0.1 wt%, more than 0.5 wt%, more than 1 wt%, more than 2 wt%, more than 3 wt%, more than 4 wt%, more than 5 wt%, more than 6 wt%, more than 7 wt%, more than 8 wt%, more than 9 wt%, more than 9.5 wt%, more than 9.9 wt%, or more than rare earth metal. In terms of upper limits, the contact layer may comprise less than 10 wt%, e.g., less than 9 wt%, less than 8 wt%, less than 7 wt%, less than 6 wt%, less than 5 wt%, less than 4 wt%, less than 3 wt%, less than 2 wt%, less than 1 wt%, less than 0.5 wt%, less than 0.1 wt%, less than 0.05 wt%, less than 0.01 wt%, less than 0.005 wt%, or even less. In some cases, the rare earth metal comprises samarium, and the samarium is present in the amounts described above. In some embodiments, the remaining amount or remainder of the contact layer may be a precious metal, such as silver.

[0029]

[0040] In some embodiments, the contact layer may comprise 50 wt% to 99.9 wt%, e.g., 50 wt% to 99 wt%, 55 wt% to 95 wt%, 60 wt% to 90 wt%, 65 wt% to 85 wt%, or 70 wt% to 80 wt% of a precious metal, e.g., silver, based on the total weight of the contact layer. In terms of lower limits, the contact layer may comprise more than 50 wt%, e.g., more than 55 wt%, more than 60 wt%, more than 65 wt%, more than 70 wt%, more than 75 wt%, more than 80 wt%, more than 85 wt%, more than 90 wt%, more than 95 wt%, more than 98 wt%, more than 99 wt%, more than 99.5 wt%, or more precious metal. In terms of upper limits, the contact layer can comprise less than 99.9 wt%, e.g., less than 99 wt%, less than 95 wt%, less than 90 wt%, less than 85 wt%, less than 80 wt%, less than 75 wt%, less than 70 wt%, less than 65 wt%, less than 60 wt%, less than 55 wt%, less than 52 wt%, or less of the precious metal. In some cases, the precious metal comprises silver, and the silver is present in the aforementioned amounts.

[0030]

[0041] In some embodiments, the contact layer may include 0.1 wt% to 20 wt%, e.g., 0.3 wt% to 20 wt%, 0.5 wt% to 20 wt%, 1 wt% to 20 wt%, 3 wt% to 18 wt%, 5 wt% to 16 wt%, 7 wt% to 14 wt%, 9 wt% to 12 wt%, or 10 wt% to 11 wt% nickel, based on the total weight of the contact layer. In terms of lower limits, the contact layer may include more than 0.1 wt%, e.g., more than 0.3 wt%, more than 0.5 wt%, more than 1 wt%, more than 2 wt%, more than 3 wt%, more than 4 wt%, more than 5 wt%, more than 6 wt%, more than 7 wt%, more than 8 wt%, more than 9 wt%, more than 10 wt%, more than 11 wt%, more than 12 wt%, more than 13 wt%, more than 14 wt%, more than 15 wt%, more than 16 wt%, more than 17 wt%, more than 18 wt%, more than 19 wt%, more than 19.5 wt%, more than 19.9 wt%, or more than nickel. In terms of upper limits, the contact layer may comprise less than 20 wt%, e.g., less than 19 wt%, less than 18 wt%, less than 17 wt%, less than 16 wt%, less than 15 wt%, less than 14 wt%, less than 13 wt%, less than 12 wt%, less than 11 wt%, less than 10 wt%, less than 9 wt%, less than 8 wt%, less than 7 wt%, less than 6 wt%, less than 5 wt%, less than 4 wt%, less than 3 wt%, less than 2 wt%, less than 1.5 wt%, less than 1.1 wt%, less than 1 wt%, less than 0.8 wt%, less than 0.6 wt%, less than 0.5 wt%, less than 0.3 wt%, less than 0.2 wt%, less than 0.15 wt%, or less.

[0031]

[0042] In some embodiments, the contact layer may include 1 wt% to 30 wt%, e.g., 2 wt% to 30 wt%, 2 wt% to 28 wt%, 2 wt% to 26 wt%, 2 wt% to 24 wt%, 3 wt% to 22 wt%, 3 wt% to 20 wt%, 3 wt% to 18 wt%, 5 wt% to 16 wt%, 7 wt% to 14 wt%, 9 wt% to 12 wt%, or 10 wt% to 11 wt% copper, based on the total weight of the contact layer. In terms of the lower limit, the contact layer may comprise more than 1 wt%, e.g., more than 2 wt%, more than 3 wt%, more than 4 wt%, more than 5 wt%, more than 6 wt%, more than 7 wt%, more than 8 wt%, more than 9 wt%, more than 10 wt%, more than 11 wt%, more than 12 wt%, more than 13 wt%, more than 14 wt%, more than 15 wt%, more than 16 wt%, more than 17 wt%, more than 18 wt%, more than 19 wt%, more than 19.5 wt%, more than 19.9 wt%, more than 20 wt%, more than 21 wt%, more than 22 wt%, more than 23 wt%, more than 24 wt%, more than 25 wt%, more than 26 wt%, more than 27 wt%, more than 28 wt%, more than 29 wt%, more than 29.5 wt%, more than 29.9 wt%, or more than 10 wt% copper. In terms of upper limits, the contact layer may comprise less than 30 wt%, e.g., less than 29 wt%, less than 28 wt%, less than 27 wt%, less than 26 wt%, less than 25 wt%, less than 24 wt%, less than 23 wt%, less than 22 wt%, less than 21 wt%, less than 20 wt%, less than 19 wt%, less than 18 wt%, less than 17 wt%, less than 16 wt%, less than 15 wt%, less than 14 wt%, less than 13 wt%, less than 12 wt%, less than 11 wt%, less than 10 wt%, less than 9 wt%, less than 8 wt%, less than 7 wt%, less than 6 wt%, less than 5 wt%, less than 4 wt%, less than 3 wt%, less than 2 wt%, less than 1.5 wt%, less than 1.1 wt%, or even less than copper.

[0032]

[0043] In some embodiments, the contact layer may comprise between 0.001 wt% and 10 wt%, e.g., between 0.1 wt% and 9 wt%, 1 wt% and 8 wt%, 2 wt% and 7 wt%, 3 wt% and 6 wt%, or 4 wt% and 5 wt% zinc, based on the total weight of the contact layer. In terms of lower limits, the contact layer may comprise 0.001 wt%, e.g., greater than 0.005 wt%, greater than 0.01 wt%, greater than 0.05 wt%, greater than 0.1 wt%, greater than 0.5 wt%, greater than 1 wt%, greater than 2 wt%, greater than 3 wt%, greater than 4 wt%, greater than 5 wt%, greater than 6 wt%, greater than 7 wt%, greater than 8 wt%, greater than 9 wt%, greater than 9.5 wt%, greater than 9.9 wt%, or more zinc. In terms of upper limits, the contact layer may contain less than 10 wt%, e.g., less than 9 wt%, less than 8 wt%, less than 7 wt%, less than 6 wt%, less than 5 wt%, less than 4 wt%, less than 3 wt%, less than 2 wt%, less than 1 wt%, less than 0.5 wt%, less than 0.1 wt%, less than 0.05 wt%, less than 0.01 wt%, less than 0.005 wt%, or even less than 1 wt% zinc.

[0033]

[0044] In some embodiments, when the contact layer is exposed to air, the oxide, e.g., samarium oxide, that may form on the surface of the contact layer may be in the range of 0.01 wt% to 0.1 wt%, e.g., 0.02 wt% to 0.1 wt%, 0.02 wt% to 0.09 wt%, 0.03 wt% to 0.09 wt%, 0.03 wt% to 0.08 wt%, 0.04 wt% to 0.07 wt%, or 0.04 wt% to 0.06 wt%, based on the total weight of the contact layer. In terms of lower limits, the contact layer may comprise more than 0.01 wt%, e.g., more than 0.02 wt%, more than 0.03 wt%, more than 0.04 wt%, more than 0.05 wt%, more than 0.06 wt%, more than 0.07 wt%, more than 0.08 wt%, more than 0.09 wt%, more than 0.095 wt%, or more. In terms of upper limits, the contact layer may comprise less than 0.1 wt%, less than 0.09 wt%, less than 0.08 wt%, less than 0.07 wt%, less than 0.06 wt%, less than 0.05 wt%, less than 0.04 wt%, less than 0.03 wt%, less than 0.02 wt%, less than 0.015 wt%, or less surface oxides.

[0034]

[0045] When measured based on the total weight of the contact layer, the contact layer may contain 0.01 vol% to 0.2 vol%, e.g., 0.02 vol% to 0.2 vol%, 0.02 vol% to 0.18 vol%, 0.04 vol% to 0.18 vol%, 0.04 vol% to 0.16 vol%, 0.06 vol% to 0.14 vol%, 0.08 vol% to 0.12 vol%, or 0.09 vol% to 0.11 vol% oxide. In terms of lower limits, the contact layer may contain more than 0.01 vol%, e.g., more than 0.02 vol%, more than 0.04 vol%, more than 0.06 vol%, more than 0.08 vol%, more than 0.1 vol%, more than 0.1 vol%, more than 0.12 vol%, more than 0.14 vol%, more than 0.16 vol%, more than 0.18 vol%, more than 0.19 vol%, or more surface oxide. In terms of upper limits, the contact layer may comprise less than 0.2 vol%, e.g., less than 0.18 vol%, less than 0.16 vol%, less than 0.14 vol%, less than 0.12 vol%, less than 0.1 vol%, less than 0.08 vol%, less than 0.06 vol%, less than 0.04 vol%, less than 0.02 vol%, less than 0.015 vol%, or even less than surface oxide.

[0035]

[0046] In some embodiments, the substrate may comprise pure copper. In some embodiments, the substrate may comprise a copper alloy. The copper alloy may comprise copper, nickel, and / or zinc. In some embodiments, the substrate may comprise 60 wt% to 100 wt%, e.g., 70 wt% to 100 wt%, 80 wt% to 100 wt%, 90 wt% to 100 wt%, or 95 wt% to 100 wt% copper, based on the total weight of the substrate. In terms of lower limits, the substrate may comprise more than 60 wt%, e.g., more than 70 wt%, more than 80 wt%, more than 90 wt%, more than 91 wt%, more than 92 wt%, more than 93 wt%, more than 94 wt%, more than 95 wt%, more than 96 wt%, more than 97 wt%, more than 98 wt%, more than 99 wt%, or 100 wt% copper. As noted above, many conventional low power applications employ substrates with significantly lower purity, such as lower purity copper.

[0036]

[0047] The addition of other elements to the substrate, such as nickel, zinc, etc., may be limited so that a relatively high copper content can be maintained to achieve high conductivity. The combined addition of other elements may be less than 40 wt%, less than 30 wt%, less than 20 wt%, less than 10 wt%, less than 5 wt%, less than 4 wt%, less than 3 wt%, less than 2 wt%, less than 1 wt%, less than 0.9 wt%, less than 0.8 wt%, less than 0.7 wt%, less than 0.6 wt%, less than 0.5 wt%, less than 0.4 wt%, less than 0.3 wt%, less than 0.2 wt%, less than 0.1 wt%, or less.

[0037] Contact layer performance characteristics Friction coefficient

[0048] When compared to a conventional (pure and / or electroplated) silver contact layer that may be electroplated onto a substrate, the rare earth metal-doped precious metal-based contact layer may exhibit a coefficient of friction that is at least 20% lower, e.g., 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 95% lower than the coefficient of friction of the conventional electroplated silver contact layer. In some embodiments, the precious metal-based contact layer may exhibit a coefficient of friction of 0.01 to 1.4, e.g., 0.01 to 1.4, 0.05 to 1.4, 0.2 to 1.4, 0.2 to 1.2, 0.2 to 1, 0.3 to 0.9, 0.3 to 0.8, 0.3 to 0.7, or 0.4 to 0.6, as measured according to ASTM G99-17. In terms of upper limits, the coefficient of friction of the precious metal-based contact layer can be less than 1.4, e.g., less than 1.3, less than 1.2, less than 1.1, less than 1, less than 0.9, less than 0.8, less than 0.7, less than 0.6, less than 0.5, less than 0.4, less than 0.3, less than 0.2, or less than 0.15. Depending on the particular geometric design, the coefficient of friction measurement can also be performed using one of the tests including ASTM D3702, ASTM G77, ASTM G83, ASTM G115, and / or ASTM G133.

[0038] hardness

[0049] The noble metal-based contact layer may also exhibit improved hardness compared to conventional electroplated silver contact layers, thus enabling improved wear / erosion resistance. The hardness of the contact layer may be evaluated using the Vickers hardness scale, and the measured hardness value may be expressed as a Vickers number (HV). Tests employed to measure the hardness of the contact layer may include ASTM E384-17. In some embodiments, the noble metal-based contact layer has a hardness of 25HV to 200HV according to the Vickers hardness scale, e.g., 25HV to 175HV, 25HV to 150HV, 25HV to 125HV, 25HV to 100HV, 25HV to 75HV, 25HV to 50HV, 50HV to 200HV, 50HV to 175HV, 50HV to 150HV, 50HV to 125HV, 50HV to 100HV, 50HV to 75HV, 75HV to The hardness may be in the range of 200HV, 75HV to 175HV, 75HV to 150HV, 75HV to 125HV, 75HV to 100HV, 100HV to 200HV, 100HV to 175HV, 100HV to 150HV, 100HV to 125HV, 100HV to 120HV, 125HV to 200HV, 125HV to 175HV, 125HV to 150HV, 150HV to 175HV, or 175HV to 200HV. In terms of lower limits, the noble metal-based contact layer may exhibit a hardness of greater than 25 HV, e.g., greater than 50 HV, 60 HV, 70 HV, 80 HV, 90 HV, 100 HV, 125 HV, 150 HV, 175 HV, 180 HV, 190 HV, 195 HV, or more. In terms of upper limits, the noble metal-based contact layer may exhibit a hardness of less than 200 HV, e.g., less than 175 HV, 150 HV, 125 HV, 100 HV, 90 HV, 80 HV, 70 HV, 60 HV, 50 HV, 40 HV, 30 HV, or less.

[0039] electricity

[0050] Despite the formation of surface oxides that result in a reduced coefficient of friction and reduced insertion force required for operation of the charging terminal, the noble metal-based contact layer still advantageously exhibits relatively high electrical conductivity, e.g., the contact layer exhibits a synergistic combination of low coefficient of friction and high electrical conductivity. In some embodiments, the noble metal-based contact layer exhibits a conductivity of 80% IACS (4.6401×10 7S / m) ~ 100% IACS (5.8001 x 10 7 S / m), e.g., 85% IACS (4.9301 × 10 7 S / m) ~ 100% IACS (5.8001 x 10 7 S / m), 80% IACS (4.6401 × 10 7 S / m) ~ 95% IACS (5.5101 x 10 7 S / m), 90% IACS (5.2201 × 10 7 S / m) ~ 100% IACS (5.8001 x 10 7 S / m, 95% IACS (5.5101 × 10 7 S / m) ~ 100% IACS (5.8001 x 10 7 S / m), 85% IACS (4.9301 × 10 7 S / m) ~ 95% IACS (5.5101 x 10 7 S / m), or 90% IACS (5.2201 × 10 7 S / m) ~ 95% IACS (5.5101 x 10 7 On the lower end, noble metal-based contact layers can exhibit conductivities in the range of greater than 80% IACS (4.6401×10 7 S / m), e.g., over 82% IACS (4.7561 × 10 7 S / m), over 84% IACS (4.8721 × 10 7 S / m), over 86% IACS (4.9881 × 10 7 S / m), over 88% IACS (5.1041 × 10 7 S / m), over 90% IACS (5.2201 × 10 7 S / m), over 92% IACS (5.3361 × 10 7 S / m), over 94% IACS (5.4521 × 10 7 S / m), over 96% IACS (5.5681 × 10 7 S / m), over 98% IACS (5.6841 × 10 7 S / m), over 99% IACS (5.7421 × 10 7 S / m), or 100% IACS (5.8001 x 10 7 It can exhibit a conductivity of 1000 kJ / m.

[0040]

[0051] In some embodiments, the overall conductivity of the layered structure is 80% (4.6401×10 7 S / m) IACS to 100% IACS (5.8001 x 10 7 S / m), e.g., 85% IACS (4.9301 × 10 7 S / m) ~ 100% IACS (5.8001 x 10 7 S / m) 80% IACS (4.6401 x 10 7 S / m) ~ 95% IACS (5.5101 x 10 7 S / m), or 85% IACS (4.9301 × 10 7 S / m) ~ 95% IACS (5.5101 x 10 7 On the lower end, the layered structure can have a viscosity greater than 80% IACS (4.6401 x 10 7 S / m), e.g., over 82% IACS (4.7561 × 10 7 S / m), over 84% IACS (4.8721 × 10 7 S / m), over 86% IACS (4.9881 × 10 7 S / m), over 88% IACS (5.1041 × 10 7 S / m), over 90% IACS (5.2201 × 10 7 S / m), over 92% IACS (5.3361 × 10 7 S / m), over 94% IACS (5.4521 × 10 7 S / m), over 96% IACS (5.5681 × 10 7 S / m), over 98% IACS (5.6841 × 10 7 S / m), over 99% IACS (5.7421 × 10 7 S / m) or higher overall conductivity.

[0041]

[0052] Furthermore, due to the reduced coefficient of friction and improved wear / erosion resistance, the precious metal-based contact layer can maintain a smooth contact surface, thereby maintaining its electrical performance, such as high conductivity and low contact resistance, throughout the operating life of the charging terminal. Additionally, with the improved wear / erosion resistance, a thinner contact layer can be realized compared to conventional electroplated silver contact layers. The overall thickness of the charging terminal can be maintained by increasing the thickness of the substrate, if desired. Therefore, the overall cost of manufacturing the charging terminal can be reduced while achieving excellent electrical performance.

[0042] Thickness

[0053] In some embodiments, the contact layer may have a thickness in the range of 2 μm to 100 μm, 2 μm to 50 μm, 3 μm to 40 μm, 4 μm to 35 μm, 5 μm to 40 μm, 5 μm to 35 μm, 10 μm to 30 μm, 10 μm to 25 μm, or 15 μm to 20 μm. In terms of upper limits, the contact layer may have a thickness of less than 40 μm, e.g., less than 35 μm, less than 30 μm, less than 25 μm, less than 20 μm, less than 15 μm, less than 10 μm, less than 7 μm, or less. In terms of lower limits, the contact layer may have a thickness greater than 5 μm, e.g., greater than 10 μm, greater than 15 μm, greater than 20 μm, or even greater.

[0043]

[0054] As discussed above, oxides can form on the surface of the contact layer when certain metals, such as rare earth metals, contained in the contact layer are exposed to air. Depending on the content of the oxide-forming metal and the environment to which the contact layer may be exposed, the oxide, e.g., samarium oxide, may have a thickness of 0.001 μm to 50 μm, e.g., 0.001 μm to 40 μm, 0.001 μm to 30 μm, 0.001 μm to 20 μm, 0.001 μm to 10 μm, 0.001 μm to 5 μm, 0.001 μm to 3 μm, 0.001 μm to 1 μm, 0.001 μm to 0.5 μm, 0.001 μm to 0.1 μm, 0.001 μm to 0.0 μm, or 0.001 μm to 0.0 μm. 5μm, 0.001μm~0.01μm, 0.001μm~0.005μm, 0.005μm~50μm, 0.005μm~40μm, 0.005μm~30μm, 0.005μm~20μm, 0.005μm~10μm, 0.0 05μm~5μm, 0.005μm~3μm, 0.005μm~1μm, 0.005μm~0.5μm, 0.005μm~0.1μm, 0.005μm~0.05μm, 0.005μm~0.01μm, 0.01μm~50μm, 0 .01μm~40μm, 0.01μm~30μm, 0.01μm~20μm, 0.01μm~10μm, 0.01μm~5μm, 0.01μm~3μm, 0.01μm~1μm, 0.01μm~0.5μm, 0.01μm~0.1 μm, 0.01μm~0.05μm, 0.05μm~50μm, 0.05μm~40μm, 0.05μm~30μm, 0.05μm~20μm, 0.05μm~10μm, 0.05μm~5μm, 0.05μm~3μm, 0.05 μm~1μm, 0.05μm~0.5μm, 0.05μm~0.1μm, 0.1μm~50μm, 0.1μm~40μm, 0.1μm~30μm, 0.1μm~20μm, 0.1μm~10μm, 0.1μm~5μm, 0.1μm ~3μm, 0.1μm~1μm, 0.1μm~0.5μm, 0.5μm~50μm, 0.5μm~40μm, 0.5μm~30μm, 0.5μm~20μm, 0.5μm~10μm, 0.5μm~5μm, 0.5μm~3μm, 0.5μm~1μm, 1μm~50μm, 1μm~40μm, 1μm~30μm, 1μm~20μm, 1μm~10μm, 1μm~5μm, 1μm~3μm, 3μm ~50μm, 3μm~40μm, 3μm~30μm, 3μm~20μm, 3μm~10μm, 3μm~5μm, 5μm~50μm, 5μm~40μm, 5μm~3 The oxides may be distributed over a depth of the contact layer ranging from 0 μm, 5 μm to 20 μm, 5 μm to 10 μm, 10 μm to 50 μm, 10 μm to 40 μm, 10 μm to 30 μm, 10 μm to 20 μm, 20 μm to 50 μm, 20 μm to 40 μm, 20 μm to 30 μm, 30 μm to 50 μm, 30 μm to 40 μm, or 40 μm to 50 μm. In terms of the lower limit, the oxides may be distributed over a depth of more than 0.001 μm, e.g., more than 0.005 μm, more than 0.01 μm, more than 0.05 μm, more than 0.1 μm, more than 0.5 μm, more than 1 μm, more than 3 μm, more than 5 μm, more than 10 μm, more than 20 μm, more than 30 μm, more than 40 μm, more than 45 μm, or more from the surface of the contact layer. In terms of upper limits, the oxides may be distributed from the surface of the contact layer over a depth of less than 50 μm, e.g., less than 40 μm, less than 30 μm, less than 20 μm, less than 10 μm, less than 5 μm, less than 3 μm, less than 1 μm, less than 0.5 μm, less than 0.1 μm, less than 0.05 μm, less than 0.01 μm, less than 0.005 μm, or even less.

[0044]

[0055] Depending on the application, the total thickness of the layered structure can be in the range of 0.1 mm to 5 mm, e.g., 0.1 mm to 4 mm, 0.1 mm to 3 mm, 0.1 mm to 2.5 mm, 0.5 mm to 2 mm, or 1 mm to 1.5 mm. In terms of upper limits, the total thickness of the layered structure can be less than 5 mm, less than 4.5 mm, less than 4 mm, less than 3.5 mm, less than 3 mm, less than 2.5 mm, less than 2 mm, less than 1.5 mm, less than 1 mm, less than 0.5 mm, less than 0.3 mm, less than 0.2 mm, or less. In terms of lower limits, the total thickness of the layered structure can be greater than 0.1 mm, e.g., greater than 0.5 mm, greater than 1 mm, greater than 1.5 mm, greater than 2 mm, greater than 3 mm, greater than 4 mm, greater than 4.5 mm, or more.

[0045] Electrical characteristics of charging terminals

[0056] Depending on the thickness of the contact layer and / or the thickness of the substrate, as well as the design of the charging terminal, charging terminals manufactured using a layered structure can have a capacitance of 4.64 x 10 7 S / m~5.8×10 7 S / m, e.g., 4.7×10 7 S / m~5.8×10 7 S / m, 4.8×10 7 S / m~5.8×10 7 S / m, 4.9 × 10 7 S / m~5.8×10 7 S / m, 5.0×10 7 S / m~5.8×10 7 S / m, 5.1 x 10 7 S / m~5.8×10 7 S / m, 5.2 × 10 7 S / m~5.8×10 7 S / m, 5.3 × 10 7 S / m~5.8×10 7 S / m, 5.4 × 10 7 S / m~5.8×10 7 S / m, 5.5 x 10 7 S / m~5.8×10 7 S / m, 5.6×10 7 S / m~5.8×10 7 S / m, or 5.7 x 10 7 S / m~5.8×10 7 The conductivity of the charging terminals can be in the range of 4.64 x 10 S / m. 7 S / m or more, e.g., 4.7×10 7 Over S / m, 4.8×10 7 Over S / m, 4.9×10 7 S / m over, 5.0×10 7 More than S / m, 5.1×10 7 Over S / m, 5.2×10 7 Over S / m, 5.3×10 7 More than S / m, 5.4×10 7 More than S / m, 5.5×10 7 More than S / m, 5.6×10 7 Over S / m, 5.7×10 7 Over S / m, 5.75×10 7The conductivity ranges mentioned above are also applicable to charging terminals fabricated using layered structures.

[0046] Exemplary Layered Structures

[0057] FIG. 1 schematically illustrates a layered structure 100 that can be used to form or manufacture a charging terminal or contact. The layered structure 100 can include a substrate 102 and a contact layer 104 disposed on the substrate 102. While FIG. 1 illustrates that the contact layer 104 is disposed over the entire substrate 102, in some embodiments, the contact layer 104 can be disposed over one or more portions of the substrate 102. The substrate 102 can be made of a (high) electrical conductor, such as a metal or metal alloy, more specifically, for example, copper or a copper alloy, for conducting current through the charging terminal. The substrate 102 can be configured to provide mechanical support to the contact layer 104 and / or maintain the structural integrity of the formed charging terminal.

[0047]

[0058] As described herein, the contact layer 104 may include a precious metal-based contact layer with the addition of a rare earth metal. The addition of the rare earth metal may create surface properties that provide low electrical contact resistance and / or good abrasion and / or wear resistance, thereby improving the overall performance of the resulting charging terminal. Furthermore, the addition of the rare earth metal may achieve a low coefficient of friction for the contact layer 104, thereby achieving a low insertion force for the charging terminal and improving user operability.

[0048]

[0059] FIG. 2 schematically illustrates another layered structure 200 that can be used to form or manufacture a charging terminal or contact. Layered structure 200 differs from layered structure 100 in that layered structure 200 can further include a second or lower contact layer 206 disposed below substrate 102. Contact layer 206 can include a material composition that is the same as or similar to that of contact layer 102. Thus, layered structure 200 can be used to form a charging terminal that includes two electrical contact surfaces, one formed by contact layer 102 and the other by contact layer 206, both of which can exhibit low friction, low contact resistance, and / or high wear / erosion resistance. While FIG. 2 illustrates contact layer 206 disposed over the entire lower surface of substrate 102, in some embodiments, contact layer 206 can be disposed over a portion or portions of the lower surface of substrate 102.

[0049]

[0060] FIG. 3 schematically illustrates another layered structure 300 that can be used to form or fabricate a charging terminal or contact. The layered structure 300 differs from the layered structure 100 in that the layered structure 300 can include a rare earth metal-doped precious metal-based contact layer that is inlaid or embedded in the substrate 102. The surface of the precious metal-based contact layer 304 can be flush with the surface of the substrate 102. Thus, the precious metal-based contact layer 304 can also be referred to as a precious metal-based inlay 304. While FIG. 3 illustrates the precious metal-based contact layer or inlay 304 being disposed at or near a central region of the surface of the substrate 102, in some embodiments, the precious metal-based contact layer or inlay 304 can be eccentric with respect to the substrate 102, at or near an edge of the substrate 102, or in any suitable location depending on the design of the charging terminal to be fabricated from the layered structure 300.

[0050]

[0061] 4 schematically illustrates another layered structure 400 that can be used to form or manufacture a charging terminal or contact. The layered structure 400 can include a first precious metal-based contact layer 404 doped with a rare earth metal that is inlaid or embedded in a first surface of the substrate 102. The surface of the first precious metal-based contact layer 404 can be flush with the first surface of the substrate 102. The layered structure 400 can further include a second precious metal-based contact layer 406 doped with a rare earth metal that is inlaid or embedded in a second surface of the substrate 102 opposite the first surface of the substrate 102. The surface of the second precious metal-based contact layer 404 can be flush with the second surface of the substrate 102. Accordingly, the first and second precious metal-based contact layers 404, 406 can also be referred to as first and second precious metal-based inlays 404, 406, respectively. In some embodiments, the first and second precious metal based contact layers or inlays 404, 406 are offset from one another as shown in Figure 4. In some embodiments, the first and second precious metal based contact layers or inlays 404, 406 may overlap one another or may be aligned with one another, depending on the design of the charging terminal being manufactured.

[0051]

[0062] 5 schematically illustrates another layered structure 500 that can be used to form or fabricate a charging terminal or contact. Layered structure 500 differs from layered structure 100 in that layered structure 500 can further include a diffusion barrier 510 disposed between substrate 102 and noble metal-based contact layer 104. Diffusion barrier 510 can prevent atoms from the substrate, e.g., a copper substrate, from migrating from substrate 102 to noble metal-based contact layer 104, e.g., a contact layer containing silver and samarium, at elevated temperatures. In some embodiments, a diffusion barrier can also be disposed between any of the inlays and the substrate, e.g., between any of inlays 304, 404, 406 and substrate 102. Diffusion barrier 510 can include nickel, niobium, or other suitable materials, or a combination thereof.

[0052]

[0063] In some embodiments, the diffusion barrier 510 can have a thickness in the range of 0.01 mm to 0.05 mm, e.g., 0.01 mm to 0.04 mm, 0.01 mm to 0.03 mm, 0.01 mm to 0.02 mm, 0.02 mm to 0.05 mm, 0.02 mm to 0.04 mm, 0.02 mm to 0.03 mm, 0.03 mm to 0.05 mm, 0.03 mm to 0.04 mm, or 0.04 mm to 0.05 mm. In terms of lower limits, the thickness of the diffusion barrier 510 can be greater than 0.01 mm, e.g., greater than 0.02 mm, greater than 0.03 mm, greater than 0.04 mm, greater than 0.045 mm, or even greater. In terms of upper limits, the thickness of the diffusion barrier 510 can be less than 0.05 mm, e.g., less than 0.04 mm, less than 0.03 mm, less than 0.02 mm, less than 0.015 mm, or less.

[0053]

[0064] FIG. 6 schematically illustrates another layered structure 600 that can be used to form or manufacture a charging terminal or charging contact. Layered structure 600 differs from layered structure 100 in that layered structure 600 may further include a reinforcing layer 612 disposed on a surface of substrate 102 opposite the surface of substrate 102 on which contact layer 104 is disposed. Reinforcing layer 612 may provide mechanical support or rigidity to layered structure 500, which in turn may improve the robustness of the manufactured charging terminal and enable the charging terminal to maintain its structural integrity throughout its operational life. In some embodiments, layered structure 300 shown in FIG. 3 and layered structure 500 shown in FIG. 5 may also include a reinforcing layer similar to reinforcing layer 612 shown in FIG. 6. Reinforcing layer 612 may include a high-strength alloy, such as a high-strength copper-based alloy or iron-based alloy. In some embodiments, reinforcing layer 612 may include steel.

[0054]

[0065] In some embodiments, the reinforcing layer 612 has a thickness of 0.1 mm to 1 mm, e.g., 0.1 mm to 0.9 mm, 0.1 mm to 0.8 mm, 0.1 mm to 0.7 mm, 0.1 mm to 0.6 mm, 0.1 mm to 0.5 mm, 0.1 mm to 0.4 mm, 0.1 mm to 0.3 mm, 0.1 mm to 0.2 mm, 0.2 mm to 1 mm, 0.2 mm to 0.9 mm, 0.2 mm to 0.8 mm, 0.2 mm to 0.7 mm, 0.2 mm to 0.6 mm, 0.2 mm to 0.5 mm, 0.2 mm to 0.4 mm, 0.2 mm to 0.3 mm, 0.3 mm to 1 mm, 0.3 mm to 0.9 mm, 0.3 mm to 0.8 mm, 0.3 mm to 0.7 mm, 0.3 mm to 0.6 mm The thickness may range from 0.3 mm to 0.5 mm, 0.3 mm to 0.4 mm, 0.4 mm to 1 mm, 0.4 mm to 0.9 mm, 0.4 mm to 0.8 mm, 0.4 mm to 0.7 mm, 0.4 mm to 0.6 mm, 0.4 mm to 0.5 mm, 0.5 mm to 1 mm, 0.5 mm to 0.9 mm, 0.5 mm to 0.8 mm, 0.5 mm to 0.7 mm, 0.5 mm to 0.6 mm, 0.6 mm to 1 mm, 0.6 mm to 0.9 mm, 0.6 mm to 0.8 mm, 0.6 mm to 0.7 mm, 0.7 mm to 1 mm, 0.7 mm to 0.9 mm, 0.7 mm to 0.8 mm, 0.8 mm to 1 mm, 0.8 mm to 0.9 mm, or 0.9 mm to 1 mm. In terms of a lower limit, the thickness of the reinforcement layer 612 can be greater than 0.1 mm, such as greater than 0.2 mm, greater than 0.3 mm, greater than 0.4 mm, greater than 0.5 mm, greater than 0.6 mm, greater than 0.7 mm, greater than 0.8 mm, greater than 0.9 mm, greater than 0.95 mm, or more. In terms of an upper limit, the thickness of the reinforcement layer 612 can be less than 1 mm, such as less than 0.9 mm, less than 0.8 mm, less than 0.7 mm, less than 0.6 mm, less than 0.5 mm, less than 0.4 mm, less than 0.3 mm, less than 0.2 mm, less than 0.15 mm, or less.

[0055]

[0066] Although various layered structures in planar geometries are shown in Figures 1-6, the layered structures are not limited to planar geometries. Depending on the application, round shapes, such as wires, rods, etc., or any other desired shape may be fabricated using various methods described herein, such as cladding, coextrusion, etc., which are discussed in more detail below.

[0056] method

[0067] The various layered structures described herein can be manufactured by cladding or any other suitable method. Cladding is a continuous metallurgical joining method in which two or more alloys are metallurgically joined, for example, in a continuous coil. Cladding can include roll cladding, hot or warm cladding, coextrusion, etc.

[0057]

[0068] In the case of rolled cladding, the incoming materials are thoroughly cleaned and then bonded in a specialized rolling mill. Their total thickness is reduced by more than 50%, e.g., more than 60%, 70%, 80%, or even more than 90%, creating a new oxide-free surface at the alloy interface. This high-pressure bonding creates atomic contact between the layers. In some embodiments, a subsequent second heat treatment can be utilized to drive diffusion and alloying between the clad layers, strengthening the metallurgical bond between the alloys of adjacent layers.

[0058]

[0069] In hot or warm cladding, heat is used during the roll cladding process to cause thermal diffusion of the layers in the initial bonding step. Hot or warm cladding allows for a lower percentage thickness reduction while achieving a metallurgical bond between the alloys of adjacent layers without the need for a second heat treatment.

[0059]

[0070] In coextrusion, a circular or cylindrical shape is drawn or extruded through a die, significantly reducing the cross-sectional area of ​​the material. Similar to rolled cladding, this linear expansion creates new surface contact under great pressure. This also creates atomic contact between layers, allowing for diffusion and metallurgical bonding of adjacent alloys. Geometries other than flat strips are possible with coextrusion.

[0060]

[0071] FIG. 7 diagrammatically illustrates an embodiment of a cladding method. Specifically, FIG. 7 diagrammatically illustrates a selective cladding method. As illustrated, two layers of material, e.g., two layers of different alloys, can have different widths. The narrow layer can be sandwiched by the cladding into the wider layer. The selective cladding method can be used, for example, to fabricate layered structure 300 and / or layered structure 400 described above.

[0061]

[0072] 8A schematically illustrates another embodiment of a cladding method. Specifically, FIG. 8A illustrates a full-coverage cladding method. Full-coverage cladding can be used to bond a full-width contact layer, such as contact layer 104 described above, to a substrate and a stiffening layer, such as stiffening layer 612 described above, to a substrate.

[0062]

[0073] FIG. 8B shows a schematic illustrating further details of an embodiment of the cladding process. Specifically, FIG. 8B shows three layers of material entering one side of a rotating roll configured to reduce the combined thickness of the three layers by approximately 60%, or any other desired percentage. As shown, the structure exiting the rotating roll has a significantly reduced thickness with the three layers in intimate contact. The newly created contact surface at the interface breaks the oxide boundary and creates atomic contact between the layers.

[0063]

[0074] Cladding offers several advantages not achievable with conventional coating methods, such as electroplating. For example, electroplating can only be used to form pure metal coatings. In other words, electroplating cannot be used to form alloy contact layers, such as the contact layers described herein that contain rare earth metals. Additionally, cladding allows for several geometric and design options, such as diffusion barriers and / or backing layers, improving the overall performance of various layered structures and the charging terminals produced therefrom. Furthermore, cladding can optimize the surface benefits provided by precious metal-based contact layers or inlays by applying the contact layers or inlays at selected locations on the substrate to create composite structures that exhibit high overall conductivity, physical strength, and rigidity.

[0064] Exemplary charging terminals

[0075] Figure 9A schematically illustrates another layered structure 900 that can be used to form or fabricate a charging terminal or contact. Layered structure 900 is similar to layered structure 300 shown in Figure 3, except that a precious metal-based contact layer or inlay 904 is disposed on the edge of substrate 102. Figure 9B schematically illustrates a plug end 910 of a charging terminal fabricated using layered structure 900, and Figure 9C schematically illustrates a receptacle end 920 of a charging terminal fabricated using layered structure 900.

[0065]

[0076] In operation, the tip or cylindrical end of the plug end 910 is inserted into the receptacle end 920. The tail or flat end of the plug end 910 may be attached to a wire or cable that connects the plug end 910 to a battery, such as a battery used in an electric vehicle. The flat end of the receptacle end 920 may be attached to a wire or cable that connects the receptacle end 920 to a power source for charging the battery. During insertion, the outer surface of the plug end 910, defined at least in part by the precious metal-based contact layer or inlay 904, is pressed to slide along and between the two convex surfaces of the receptacle end 920, defined at least in part by the precious metal-based contact layers or inlays 904a, 904b.

[0066]

[0077] As previously discussed, oxides that may be formed from rare earth metals contained in the contact layer or inlay alloy can reduce the coefficient of friction, thereby reducing the insertion force required by a user to press the plug end 910 into the receptacle end 920 and the removal force required by a user to pull the plug end 910 from the receptacle end 920. Depending on the design of the plug end 910 and receptacle end 920 of the charging terminal, the insertion and / or removal force may be between 0.1 lb and 3.0 lb, e.g., 0.1 lb to 2.5 lb, 0.1 lb to 2.0 lb, 0.1 lb to 1.5 lb, 0.1 lb to 1.0 lb, 0.1 lb to 0.75 lb, 0.1 lb to 0.5 lb, 0.1 lb to 0.25 lb, 0.25 lb to 3.0 lb, 0.25 lb to 2.5 lb, 0.25 lb to 2.0 lb, 0.25 lb to 1.5 lb, 0.25 lb to 1.0 lb, 0.25 lb to 0.75 lb, 0.25 lb to 0.5 lb, 0.5 lb to 3.0 lb, 0 It can be in the range of 0.5lb to 2.5lb, 0.5lb to 2.0lb, 0.5lb to 1.5lb, 0.5lb to 1.0lb, 0.5lb to 0.75lb, 0.75lb to 3.0lb, 0.75lb to 2.5lb, 0.75lb to 2.0lb, 0.75lb to 1.5lb, 0.75lb to 1.0lb, 1.0lb to 3.0lb, 1.0lb to 2.5lb, 1.0lb to 2.0lb, 1.0lb to 1.5lb, 1.5lb to 3.0lb, 1.5lb to 2.5lb, 1.5lb to 2.0lb, 2.0lb to 3.0lb, 2.0lb to 2.5lb, or 2.5lb to 3.0lb. In terms of upper limits, the insertion and / or removal force can be less than 3.0 lb, e.g., less than 2.5 lb, less than 2.0 lb, less than 1.5 lb, less than 1.0 lb, less than 0.75 lb, less than 0.5 lb, less than 0.25 lb, less than 0.2 lb, less than 0.15 lb, or less. Given the reduced coefficient of friction and / or insertion and removal force, the charging terminal can operate for more than 5,000 insertion and removal cycles, e.g., more than 6,000 insertion cycles, more than 7,000 cycles, more than 8,000 cycles, more than 9,000 cycles, more than 10,000 cycles, without suffering significant loss of electrical performance, e.g., loss of efficient electrical contact (or low contact resistance), due to excessive wear at its mating surfaces.For example, over its operating life, the increase in contact resistance of the contact layer due to wear may be less than 30%, less than 20%, less than 15%, less than 10%, less than 5%, less than 3%, less than 2%, less than 1%, or even less than the initial contact resistance when the charging terminal is first placed in service.

[0067]

[0078] Although electric vehicle charging terminals are described as examples, the various layered structures described herein can be used to manufacture charging terminals for other applications, such as other high power applications, where one or more of high abrasion resistance, good electrical conductivity, low insertion force, etc. may be desirable. [Example]

[0068]

[0079] The following non-limiting examples are provided.

[0080] With samarium additives silver A precious metal / rare earth metal alloy (silver-samarium) containing copper, nickel, and zinc was prepared. A comparison alloy containing the same metals but without the samarium additive was also prepared. The composition and amounts of the components are shown in Table 1.

[0069] [Table 1]

[0070]

[0081] A layered structure including a copper substrate layer and a contact layer was formed by a cladding operation. The copper substrate layer employed copper. Copper alone had a conductivity of approximately 100 IACS. The contact layers utilized the previously described Ag-Cu-Ni-Zn-Sm alloy (Example 1) and Ag-Cu-Ni-Zn alloy (Comparative Example A). A commercially available silver-electroplated copper strip was also included as Comparative Example B.

[0071]

[0082] The layered structures were measured for hardness (ASTM E384-17), electrical conductivity (ASTM B193-20), and coefficient of friction (ASTM G99-17), and the results are shown in Table 2.

[0072] [Table 2]

[0073]

[0083] As shown in Table 2, Example 1 provided suitable hardness and conductivity and also showed significant improvement in coefficient of friction performance compared to Comparative Examples A and B, an 80% improvement compared to Comparative Example A and an 86% improvement compared to Comparative Example B. Surprisingly, the layered structure of Example 1 provided these coefficient of friction improvements without sacrificing conductivity performance compared to Comparative Example A (and with only a minimal drop in conductivity compared to Comparative Example B).

[0074]

[0084] Based on simulation estimates, when the layered structure is tested for more than 5,000 insertion / removal cycles, the layered structure is estimated to exhibit an increase in contact resistance due to wear of less than 30% compared to the initial contact resistance when the charging terminal is first placed in service.

[0075]

[0085] Furthermore, under the same test conditions, it is estimated based on simulation that the insertion force is reduced by a factor of seven (or more) compared to the same connector design employing the Sm-free silver-plated structure of Comparative Example B, for example.

[0076] Embodiment

[0086] The following embodiments are contemplated: All combinations of features and embodiments are contemplated.

[0077]

[0087] Embodiment 1: 40% IACS (2.3200 x 10 7 S / m), e.g., greater than 60% IACS (or 3.4801 × 10 7 1. A layered structure comprising: a substrate having a conductivity of greater than 1.5 S / m; and a contact layer disposed on at least a portion of the substrate, wherein the contact layer exhibits a coefficient of friction of less than 1.4 as measured in accordance with American Society for Testing and Materials (ASTM) G99-17.

[0078]

[0088] Embodiment 2: Any one of the previous embodiments, wherein the contact layer comprises a rare earth metal.

[0089] Embodiment 3: Any one of the preceding embodiments, wherein the contact layer comprises samarium.

[0079]

[0090] Embodiment 4: Any one of the preceding embodiments, wherein the contact layer comprises a noble metal-based alloy.

[0091] Embodiment 5: Any one of the preceding embodiments, wherein the contact layer comprises a silver alloy.

[0080]

[0092] Embodiment 6: Any one of the preceding embodiments, wherein the contact layer comprises a samarium-silver alloy.

[0093] Embodiment 7: Any one of the preceding embodiments, wherein the contact layer comprises samarium oxide.

[0081]

[0094] Embodiment 8: Any one of the preceding embodiments, wherein the contact layer comprises less than 0.1 wt % samarium oxide.

[0095] Embodiment 9: Any one of the preceding embodiments, wherein the contact layer comprises less than 0.2 vol.% samarium oxide.

[0082]

[0096] Embodiment 10: Any one of the previous embodiments, wherein the contact layer comprises samarium oxide distributed throughout a depth of the contact layer ranging from 0.001 μm to 50 μm, as measured from the surface of the contact layer.

[0083]

[0097] Embodiment 11: Any one of the preceding embodiments, wherein the contact layer comprises copper, nickel, or zinc, or a combination thereof.

[0098] Embodiment 12: Any one of the preceding embodiments, wherein the contact layer comprises 0.001 wt% to 10 wt% samarium; and / or 50 wt% to 99.9 wt% silver.

[0084]

[0099] Embodiment 13: Any one of the preceding embodiments, wherein the contact layer comprises 0.001 wt% to 10 wt% samarium; and / or the balance silver.

[0100] Embodiment 14: Any one of the preceding embodiments, wherein the contact layer comprises 50 wt% to 99.9 wt% silver; 0.1 wt% to 20 wt% nickel; 1 wt% to 30 wt% copper; and 0.001 wt% to 10 wt% zinc.

[0085]

[0101] Embodiment 15: Any one of the previous embodiments, wherein the substrate comprises a metal, preferably copper or a copper alloy.

[0102] Embodiment 16: Any one of the previous embodiments, wherein the contact layer exhibits a coefficient of friction in the range of 0.1 to 1.4.

[0086]

[0103] Embodiment 17: The contact layer has a viscosity of greater than 80% IACS (or 4.6401 x 10 7 Any one of the preceding embodiments, wherein the conductive material exhibits a conductivity of greater than 1000 S / m.

[0104] Embodiment 18: The contact layer has a viscosity of greater than 86% IACS (or 4.9881 x 10 7 Any one of the preceding embodiments, wherein the conductive material exhibits a conductivity of greater than 1000 S / m.

[0087]

[0105] Embodiment 19: Any one of the previous embodiments, wherein the contact layer exhibits a hardness of greater than 80 HV as measured by ASTM E384-17.

[0106] Embodiment 20: Any one of the previous embodiments, wherein the contact layer exhibits a hardness in the range of 25HV to 100HV.

[0088]

[0107] Embodiment 21: Any one of the previous embodiments, wherein the contact layer exhibits a hardness in the range of 150HV to 200HV.

[0108] Embodiment 22: The substrate has a solubility of greater than 95% IACS (or 5.5101 x 10 7 Any one of the preceding embodiments, wherein the conductive material exhibits a conductivity of greater than 1000 S / m.

[0089]

[0109] Embodiment 23: Any one of the previous embodiments, wherein the substrate exhibits a yield strength of less than 70 ksi as measured by ASTM E8 / E8M-16a.

[0110] Embodiment 24: The layered structure has a thickness of greater than 80% IACS (or 4.6401 x 10 7 Any one of the preceding embodiments, wherein the conductive material exhibits a conductivity of greater than 1000 S / m.

[0090]

[0111] Embodiment 25: Any one of the previous embodiments, wherein the contact layer has a thickness in the range of 5 μm to 40 μm.

[0112] Embodiment 26: Any one of the previous embodiments, wherein the layered structure has a thickness in the range of 0.1 mm to 5 mm.

[0091]

[0113] Embodiment 27: Any one of the previous embodiments, wherein the layered structure is formed by cladding a contact layer onto a substrate.

[0114] Embodiment 28: Any one of the preceding embodiments, wherein the layered structure further comprises a diffusion barrier disposed between the substrate and the contact layer.

[0092]

[0115] Embodiment 29: Any one of the preceding embodiments, wherein the diffusion barrier comprises nickel or niobium.

[0116] Embodiment 30: Any one of the previous embodiments, wherein the diffusion barrier has a thickness in the range of 0.01 mm to 0.05 mm.

[0093]

[0117] Embodiment 31: Any one of the preceding embodiments, wherein the layered structure further comprises a backing layer disposed on at least a portion of the substrate opposite the contact layer.

[0118] Embodiment 32: Any one of the previous embodiments, wherein the backing layer comprises a high strength copper-based alloy or iron-based alloy.

[0094]

[0119] Embodiment 33: Any one of the preceding embodiments, wherein the backing layer comprises steel.

[0120] Embodiment 34: Any one of the previous embodiments, wherein the backing layer has a thickness in the range of 0.1 mm to 1 mm.

[0095]

[0121] Embodiment 35: Any one of the preceding embodiments, wherein the substrate and / or contact layer is substantially flat.

[0122] Embodiment 36: Any one of the preceding embodiments, wherein the substrate is cylindrical and the contact layer is disposed around at least a portion of the outer surface of the cylindrical substrate.

[0096]

[0123] Embodiment 37: Any one of the preceding embodiments, wherein the layered structure is configured for high power applications.

[0124] Embodiment 38: An electrical terminal or connector of any one of the preceding embodiments, wherein the electrical terminal or connector is configured to undergo more than 5,000 insertion and extraction cycles, for example more than 10,000 insertion and extraction cycles without failure.

[0097]

[0125] Embodiment 39: Any one of the preceding embodiments, wherein the electrical terminal or connector experiences an increase in contact resistance of less than 30%, less than 15%, less than 10%, less than 5%, less than 3%, less than 2%, or less than 1% when subjected to more than 5,000 insertion and extraction cycles, such as more than 10,000 insertion and extraction cycles.

[0098]

[0126] Embodiment 40: Greater than 60% IACS (or 3.4801 x 10 7 a charging terminal comprising: a substrate having a conductivity of greater than 0.25 S / m; and a contact layer disposed on at least a portion of the substrate, wherein the charging terminal exhibits a coefficient of friction in the range of 0.1 to 1.4, as measured in accordance with ASTM G99-17.

[0099]

[0127] Embodiment 41: A contact layer composition comprising samarium; silver; nickel; copper; and / or zinc, wherein the contact layer composition exhibits a coefficient of friction in the range of 0.1 to 1.4 as measured according to ASTM G99-17.

[0100]

[0128] Embodiment 42: Any one of the preceding embodiments, comprising 0.001 wt% to 10 wt% samarium; and / or 50 wt% to 99.9 wt% silver.

[0129] Embodiment 43: Any one of the preceding embodiments, comprising: 50 wt% to 99.9 wt% silver; 0.1 wt% to 20 wt% nickel; 1 wt% to 30 wt% copper; and 0.001 wt% to 10 wt% zinc.

[0101]

[0130] Embodiment 44: The contact layer has a viscosity of greater than 86% IACS (or 4.9881 x 10 7 Any one of the preceding embodiments, wherein the conductive material exhibits a conductivity of greater than 1000 S / m.

[0131] Embodiment 45: Any one of the previous embodiments, wherein the samarium is samarium oxide.

[0102]

[0132] Embodiment 46: A method of preparing the layered structure of any one of the preceding embodiments, comprising the steps of: providing a substrate; and forming a contact layer on the substrate.

[0133] Embodiment 47: Any one of the preceding method embodiments, wherein the step of forming a contact layer on the substrate comprises forming an alloy including samarium metal on the substrate.

[0103]

[0134] Embodiment 48: Any one of the aforementioned method embodiments, wherein the step of forming a contact layer on the substrate further comprises oxidizing at least a portion of the samarium metal by exposing the contact layer to air.

[0104]

[0135] Embodiment 49: Any one of the preceding method embodiments, further comprising forming a diffusion barrier between the substrate and the contact layer, the diffusion barrier optionally comprising nickel or niobium.

[0105]

[0136] Embodiment 50: Any one of the preceding method embodiments, further comprising forming a backing layer between the substrate and the contact layer, optionally comprising a high strength copper or iron based alloy.

[0106]

[0137] Embodiment 51: Any one of the preceding method embodiments, wherein any of the contact layer, diffusion barrier and / or backing layer is obtained by cladding.

[0107]

[0138] While the present invention has been described in detail, modifications within the spirit and scope of the present invention will be readily apparent to those skilled in the art. In view of the foregoing discussion, the relevant knowledge in the art and the disclosures of the references discussed above in connection with the background and detailed description are hereby incorporated by reference in their entirety. In addition, it should be understood that aspects of the present invention and some of the various embodiments and various features recited below and / or in the appended claims may be combined or interchanged, either in whole or in part. In the foregoing description of various embodiments, embodiments that refer to separate embodiments may be appropriately combined with other embodiments, as will be understood by those skilled in the art. Furthermore, those skilled in the art will appreciate that the foregoing description is illustrative only and is not intended to be limiting. Specific embodiments of the present invention are as follows. [Aspect 1] A layered structure, 40% International Annealed Copper Standard (IACS) or 3.4801 x 10 7 a substrate having a conductivity of greater than 1000 S / m; and a contact layer disposed over at least a portion of the substrate; Including, The contact layer exhibits a coefficient of friction of less than 1.4 as measured in accordance with American Society for Testing and Materials (ASTM) G99-17. The layered structure, wherein the contact layer has a thickness in the range of 5 μm to 40 μm. [Aspect 2] 2. The layered structure of embodiment 1, wherein the contact layer comprises a rare earth metal, preferably samarium. [Aspect 3] 2. The layered structure of embodiment 1, wherein the contact layer comprises a samarium-silver alloy. [Aspect 4] 2. The layered structure of embodiment 1, wherein the contact layer comprises less than 5 wt. % samarium. [Aspect 5] the contact layer comprising: Silver, preferably 50 wt% to 99.9 wt% silver; Nickel, preferably 0.1 wt% to 20 wt% nickel; Copper, preferably 1 wt% to 30 wt% copper; and Zinc, preferably 0.001 wt% to 10 wt% zinc 2. The layered structure of embodiment 1, comprising: [Aspect 6] The contact layer or the layered structure has a surface roughness of greater than 80% IACS (or 4.6401 x 10 7 2. The layered structure of embodiment 1, exhibiting a conductivity of greater than 1000 Å / m. [Aspect 7] 2. The layered structure of embodiment 1, wherein the contact layer exhibits a hardness in the range of 100 HV to 120 HV. [Aspect 8] 2. The layered structure of embodiment 1, wherein the layered structure has a thickness in the range of 0.1 mm to 5 mm. [Aspect 9] 10. An electrical terminal or connector comprising the layered structure of embodiment 1, wherein the electrical terminal or connector is configured for more than 5,000 insertion and extraction cycles without failure. [Aspect 10] 10. The electrical terminal or connector of claim 9, wherein the electrical terminal or connector experiences an increase in contact resistance of less than 30%, less than 15%, less than 10%, less than 5%, less than 3%, less than 2%, or less than 1% when subjected to at least 5,000 insertion and extraction cycles. [Aspect 11] A charging terminal, a substrate having a conductivity greater than 40% IACS; and a contact layer disposed over at least a portion of the substrate; Including, The charging terminal exhibits a coefficient of friction in the range of 0.1 to 1.4 as measured in accordance with ASTM G99-17. [Aspect 12] A contact layer composition comprising: samarium; silver; nickel; copper; zinc Including, The contact layer composition exhibits a coefficient of friction in the range of 0.1 to 1.4 as measured in accordance with ASTM G99-17. [Aspect 13] 1. A method for preparing a layered structure, comprising: providing a substrate; forming a contact layer on the substrate; Including, the contact layer comprises samarium; silver; nickel; copper; and zinc; The method wherein the contact layer composition exhibits a coefficient of friction in the range of 0.1 to 1.4 as measured in accordance with ASTM G99-17. [Aspect 14] 14. The method of embodiment 13, wherein the forming step comprises exposing the contact layer to air to oxidize at least a portion of the samarium metal. [Aspect 15] forming a diffusion barrier between the substrate and the contact layer comprising nickel or niobium; and / or forming a backing layer between the substrate and the contact layer, the backing layer comprising a high strength copper or iron based alloy; further comprising 14. The method of embodiment 13, wherein forming any of the contact layer, the diffusion barrier, and the backing layer is optionally accomplished by cladding.

Claims

1. A layered structure, 40% International Annealed Copper Standard (IACS) (2.3200 x 10 ７ a conductive substrate having a conductivity of greater than 1000 .mu.m; and a contact layer disposed on at least a portion of the conductive substrate; Including, the contact layer comprises a samarium-silver alloy and a rare earth metal oxide; the contact layer exhibits a coefficient of friction of less than 1.4 as measured in accordance with American Society for Testing and Materials (ASTM) G99-17; The samarium-silver alloy comprises: 0.1 wt. % or more and less than 1 wt. % nickel; 1 wt. % or more and less than 10 wt. % copper; 0.1 wt. % or more and less than 1 wt. % zinc; greater than 0.05 wt. % and less than 1 wt. % samarium; and Remaining silver The layered structure comprising:

2. The layered structure of claim 1 , wherein the rare earth metal oxide comprises samarium oxide.

3. 3. The layered structure of claim 2, wherein the contact layer comprises 0.01 wt % to 0.1 wt % samarium oxide, based on the total weight of the contact layer.

4. The contact layer has a viscosity of more than 80% IACS (4.6401 x 10 ７ 10. The layered structure of claim 1, wherein the layered structure exhibits a conductivity of greater than 1000 .mu.m.

5. 10. The layered structure of claim 1, wherein the interface layer exhibits a hardness in the range of 100 HV to 120 HV.

6. 10. The layered structure of claim 1, wherein the layered structure has a thickness in the range of 0.1 mm to 5 mm and the contact layer has a thickness in the range of 5 μm to 40 μm.

7. 10. An electrical terminal or connector comprising the layered structure of claim 1, wherein the electrical terminal or connector operates for at least 5,000 insertion and extraction cycles, and the increase in contact resistance of the contact layer due to wear is less than 30% compared to the initial contact resistance when first placed in service.

8. 8. The electrical terminal or connector of claim 7, wherein the increase in contact resistance is less than 15% compared to the initial contact resistance when first placed in service.

9. A charging terminal, a conductive substrate having a conductivity greater than 40% IACS; and a contact layer disposed over at least a portion of the conductive substrate; Including, the contact layer comprises a samarium-silver alloy and a rare earth metal oxide; the charging terminal exhibits a coefficient of friction in the range of 0.1 to 1.4 as measured in accordance with ASTM G99-17; The samarium-silver alloy comprises: 0.1 wt. % or more and less than 1 wt. % nickel; 1 wt. % or more and less than 10 wt. % copper; 0.1 wt. % or more and less than 1 wt. % zinc; greater than 0.05 wt. % and less than 1 wt. % samarium; and Remaining silver The charging terminal.

10. A contact layer composition comprising: including samarium-silver alloy and samarium oxide, The samarium-silver alloy comprises: greater than 0.05 wt. % and less than 1 wt. % samarium; 0.1 wt. % or more and less than 1 wt. % nickel; 1 wt. % or more and less than 10 wt. % copper; 0.1 wt. % or more and less than 1 wt. % zinc; and Remaining silver It consists of For a charging terminal comprising: a substrate having an electrical conductivity greater than 40% IACS; and a contact layer disposed on at least a portion of the substrate, the contact layer comprising the contact layer composition; the charging terminal exhibits a coefficient of friction in the range of 0.1 to 1.4, as measured in accordance with ASTM G99-17. The contact layer composition.

11. 1. A method for preparing a layered structure, comprising: providing a conductive substrate according to claim 1; forming a contact layer on the conductive substrate; Including, the contact layer greater than 0.05 wt. % and less than 1 wt. % samarium; 0.1 wt. % or more and less than 1 wt. % nickel; 1 wt. % or more and less than 10 wt. % copper; 0.1 wt. % or more and less than 1 wt. % zinc; and Remaining silver The samarium-silver alloy comprises the forming step includes exposing the contact layer to air to oxidize at least a portion of the samarium metal to form samarium oxide; The method wherein the contact layer exhibits a coefficient of friction in the range of 0.1 to 1.4 as measured in accordance with ASTM G99-17.

12. forming a diffusion barrier between the conductive substrate and the contact layer comprising nickel; and / or forming a backing layer comprising a high strength copper or iron based alloy between the conductive substrate and the contact layer; further comprising The method of claim 11 , wherein forming any of the contact layer, the diffusion barrier, and the backing layer is optionally accomplished by cladding.

13. 3. The layered structure of claim 2, wherein the samarium oxide is distributed throughout a depth of the contact layer ranging from 0.001 μm to 40 μm, measured from the surface of the contact layer.

Images