Semi-finished product for an electrical contact element and method of processing the same

Abstract

A method of processing a semi-finished product (100) for an electrical contact element (200) is shown, wherein in a coating step (B) a coating (30) is applied to an electrically conductive base body (20) along a coating direction (S), which coating comprises Ag as a component, in particular as a matrix, wherein in a processing step (Z) after the coating step (B) the coating (30) is processed by shaping, in particular by stretching with a sliding action through an opening (91) or by profile rolling. Also shown is a semi-finished product (100) for an electrical contact element (200), wherein the semi-finished product (100) comprises an electrically conductive base body (20) and a coating (30) on the base body (20), wherein the coating (30) comprises Ag as a component, in particular as a matrix, and is changed by shaping, in particular by stretching with a sliding action or by profile rolling.

Description

Technical Field

[0001] This invention relates to a method for processing semi-finished products for electrical contact elements. Background Technology

[0002] The semi-finished product can, for example, be constructed as an elongated shape and used to form a cage-like receiving portion for mating contact elements. It is known that in the coating step, a coating containing Ag (silver) is applied to the conductive substrate of the semi-finished product in a coating direction. This can, for example, improve the transition resistance.

[0003] Coatings applied in this manner typically do not have the desired hardness and low contact resistance or the desired low coefficient of friction. Summary of the Invention

[0004] Therefore, the object of the present invention is to provide a solution in which a semi-finished product has desired preferred characteristics.

[0005] According to the invention, this is achieved by treating the coating in a forming step during a processing or finishing step following the coating step, for example, by stretching a semi-finished product with a sliding action via an opening or by profile rolling. The desired properties can be obtained through the forming step.

[0006] In the semi-finished product according to the invention, the coating comprises Ag as a component, for example as a matrix coating, and is modified by forming steps, particularly by stretching or profile rolling with a sliding action. The semi-finished product and / or coating may, for example, correspond to openings relative to the cross-section and / or have (micro)grooves or (micro)patterns, which are produced by stretching with a sliding action or by profile rolling.

[0007] The solution according to the invention can be further improved by the following further developments and configurations, each of which is preferred and can be combined as needed.

[0008] During the forming process, a force perpendicular to the surface can be applied to the coating. This can cause changes in the coating.

[0009] The coating can surround the substrate circumferentially. For this semi-finished product, ensuring proper alignment is no longer necessary during further processing to form the contact element. At least prior to the forming processing steps, the coating can comprise a constant thickness circumferentially. In other configurations, the coating thickness can vary circumferentially, depending on the desired properties and extent therein.

[0010] In alternative configurations, the coating may be applied only to the circumferential portion. For example, in a rectangular cross-section, the coating may be applied only to one side. This side may be, for example, a side with a contact surface provided thereon, or a side used to mechanically guide the contact element.

[0011] The semi-finished product can be wire, especially round or shaped wire. Wire can be used in many ways to produce contact elements. In this case, the stretching by sliding action can be wire stretching.

[0012] The substrate itself can be produced prior to the coating step by stretching or profile rolling with a sliding action. The substrate can also be considered a semi-finished product as it undergoes further processing steps.

[0013] In alternative configurations, the semi-finished product can be an elongated element. In particular, it can have a constant cross-section along the longitudinal direction. The cross-section can be elliptical, rectangular, polygonal, or any other shape.

[0014] To further influence performance in a desired manner, the coating may have at least one additional component. The term "component" here should be understood specifically as a material component, meaning that the material of the coating is composed of or contains these material components.

[0015] In a preferred configuration of this method, Ag and other components can be applied as separate layers or within separate layers. Therefore, this method is particularly easy to implement.

[0016] Coatings and layers can be applied by conventional methods, such as hot-dip plating, electroplating, mechanical methods such as plating, or by PVD (physical vapor deposition) or CVD (chemical vapor deposition).

[0017] To enhance the forming effect, Ag and other components can be applied as alternating layers or within alternating layers. In each case, different materials exist in two consecutive layers. In this case, the alternating layers consist of at least one Ag layer, one layer of other components, and a second Ag layer. The two Ag layers can include layers with other components. Preferably, four or more layers are present. In particular, these can be repeated according to a defined pattern, such as ABABAB… or ABCABC-…

[0018] In a further preferred configuration, at least two consecutive layers may be composed of the same material. For example, in terms of process, it is easier to apply two thinner layers of one material, followed by a thin layer of another different material, such as AABAB…

[0019] In a preferred configuration, the Ag layer thickness is between 100 and 2000 nm, preferably between 200 and 1000 nm, and specifically between 300 and 600 nm. The layer thickness of the additional components can be between 5 and 200 nm, preferably between 10 and 100 nm, and especially between 30 and 60 nm. At such layer thicknesses, the forming effect is particularly effective.

[0020] The alloy content of other components in the coating can be 0.3-15%, preferably 0.5-10%. This can result in the coating having particularly preferred properties, especially mechanical properties. Here, the percentage is given as a percentage of the number of atoms of the other component relative to the total number of atoms in the coating.

[0021] Ag and other components can be alloyed through forming. In particular, these components can be mechanically alloyed. This can be achieved by mixing under high pressure during forming, for example, by drawing the wire through an open / drawing ring. To obtain particularly good results here, a large number of layers with small layer thicknesses can be used. In particular, at least 8 layers are possible, preferably at least 16 layers.

[0022] In a preferred configuration, a material that hardens the Ag matrix during alloying is used as an additional component. The alloy of Ag and other components can be harder than Ag itself. The hardness achieved in this way reduces wear, thereby extending the service life of the contact elements produced.

[0023] For example, the additional component comprises at least one material selected from the group consisting of Ni (nickel), Pd (palladium), Ru (ruthenium), Ti (titanium), Mo (molybdenum), W (tungsten), Au (gold), and Cu (copper), or is composed of at least one such material.

[0024] In another preferred configuration, the additional component can act as a barrier layer, which slows down or prevents diffusion processes within the layer, thereby improving the layer's corrosion resistance and temperature stability. Furthermore, this additional component can slow down or prevent the growth of microcrystals in the matrix, thus stabilizing the fine crystalline structure produced through forming, particularly through wire drawing. Layers produced in this way retain their hardness, abrasion resistance, and corrosion resistance even when used at high temperatures (150°C–250°C). This is especially true when nickel (Ni) is used as an additional component.

[0025] In a further preferred configuration, the additional component can be embedded as particles within the Ag layer. For example, such particles can be provided in the electroplating bath during electroplating application and can be deposited during the electroplating process. In coating methods involving immersion, the corresponding particles can also be present in the immersion bath. In vacuum deposition processes such as CVD or PVD, the second component can be deposited by co-sputtering / evaporation or coating from an Ag matrix alloy target.

[0026] Forming, particularly stretching or profile rolling with a sliding action, can impart a preferred orientation to the particles, or can alter the preferred orientation of the particles. For example, the particles can be in the form of sheets, strips, or lines, and the preferred orientation can be defined relative to the planar or longitudinal direction of these particles. In particular, the longitudinal direction of the particles can be parallel to the longitudinal direction of the matrix. Particularly, particles on the surface of a semi-finished product can thus achieve a particularly large effect. In the case of properly treated or processed semi-finished products, the particles of other components have a preferred orientation. The shape of the particles can also be changed by stretching.

[0027] Before processing, the particles may be spherical or ellipsoidal in shape. This shape can be changed by stretching. In particular, the shape can be flattened. The flat sides of this shape may be located on the surface or oriented towards the surface.

[0028] The particles can have friction-reducing properties. In particular, this can make it easier to insert or guide contact elements and / or reduce wear.

[0029] The additional component may comprise, or consist of, at least one material selected from the group consisting of graphene, graphite, carbon nanotubes, sulfides, sulfur sulfide, molybdenum sulfide, tungsten sulfide, hexagonal boron nitride, and PTFE (polytetrafluoroethylene).

[0030] By forming, particularly by stretching or profile rolling with a sliding action, a preferred orientation of microcrystals can be generated within or on the surface of the coating, or the preferred orientation of crystals on the surface or in the coating can be altered. This is independent of whether the coating consists of only a single layer or multiple layers, and also independent of the presence of particles in one or more layers.

[0031] On the surface of a semi-finished product processed or treated in this way, the crystallites may terminate primarily at one or two crystal planes. For example, these could be crystal planes. <111> and / or <110> This is especially true for Ag lattice types. If more than 30%, preferably more than 50%, of the surface is terminated along such a crystal plane, then that portion can be considered dominant.

[0032] In a particularly preferred configuration, the coating may include at least two other components besides Ag. This can have a particularly positive impact on performance.

[0033] In a further step of the process, the coated semi-finished product, formed, particularly by stretching or profile rolling with a sliding action, can be quenched and tempered. For this purpose, the semi-finished product can be heated to a specified temperature for a certain period of time, for example by passing an electric current, in an immersion bath or oven. Rapid cooling / quenching, for example by immersion, can also be part of the quenching and tempering process. In particular, the hardness of the coating and / or the semi-finished product can thus be altered.

[0034] Materials used for the matrix may specifically include copper, copper alloys, aluminum, aluminum alloys, iron, or steel to provide a particularly mechanically stable structure.

[0035] An additional layer can be provided between the substrate and the coating. This can be used, for example, to enable the applied components to adhere or to generate or increase conductivity. This additional layer may include Cu (copper) or be composed of Cu; a Ni layer or a NiP layer or an alloy metal contact layer can be used as an adhesion substrate.

[0036] The invention also includes an electrical contact element comprising at least one semi-finished product according to the invention. The contact element may have, for example, a barrel-shaped or funnel-shaped receiving portion made of the semi-finished product, into which a pin-shaped mating contact element may be inserted. Attached Figure Description

[0037] The invention will be explained in more detail below with reference to the accompanying drawings, by way of preferred configurations. The preferred further developments and configurations shown are independent of each other and can be combined with each other as needed in the application.

[0038] in:

[0039] Figure 1A-1C A schematic cross-sectional view of an embodiment of the coating step is shown;

[0040] Figure 2A-2C A schematic cross-sectional view of an embodiment of the processing steps is shown;

[0041] Figures 3A-3D A schematic cross-sectional view of another embodiment of the coating step is shown;

[0042] Figures 4A-4C A schematic cross-sectional view of another embodiment of the coating step is shown;

[0043] Figure 5 A schematic cross-sectional view of another embodiment of the semi-finished product is shown;

[0044] Figure 6 A schematic cross-sectional view of another embodiment of the processing steps is shown;

[0045] Figure 7 A schematic side view of another embodiment of a partially processed semi-finished product is shown;

[0046] Figure 8 A schematic cross-sectional view of another embodiment of the unprocessed semi-finished product is shown;

[0047] Figure 9 It shows Figure 8 Details of the cross-sectional view of the unprocessed semi-finished product;

[0048] Figure 10 It shows passing through after the processing step Figure 9 A schematic cross-sectional view of an embodiment;

[0049] Figure 11 Showing from Figure 10 Details of the cross-sectional view of the processed semi-finished product;

[0050] Figure 12 It shows Figure 10 Further magnified details of the processed semi-finished product;

[0051] Figure 13 A schematic perspective view of an embodiment of the contact element is shown. Detailed Implementation

[0052] Coating step B is shown in Figure 1A , 1B In 1C, coating 30 is applied to a conductive substrate 20, which can be understood as a semi-finished product 100. This can be accomplished by conventional methods, such as hot-dip galvanizing, mechanical coating, electroplating, physical vapor deposition (PVD), or chemical vapor deposition (CVD).

[0053] The substrate 100 can be, for example, wire 101. This wire 101 can have an elongated structure with a constant cross-section. In particular, the cross-section can be cylindrical or approximately cylindrical, but it can also be polygonal, especially rectangular or octagonal. Wire 101 can be produced by stretching or profile rolling.

[0054] In the case of wire, coating 20 can be applied along the circumferential direction U to the entire circumferential surface of the cylinder.

[0055] In other configurations, the substrate 20 can have different shapes. For example, the substrate 20 can be a plate or a strip. The plate or strip can have a rectangular or polygonal cross-section. The coating 30 can also be applied only to a portion of the outer surface. For example, in the case of a strip or plate, only one side can be coated, such as the side used for mechanical or electrical contact.

[0056] Coating 30 is applied along the coating direction S, which corresponds to the radial direction R in the case of wire 101. The layer thicknesses 81, 82, 83, and 85 of coating 30 or individual layers 31, 32, and 33 are also measured along the coating direction S or along the height direction H parallel to the coating direction S. The individual layers 31, 32, and 33 are stacked on top of each other along the coating direction S. Therefore, the coating direction S is perpendicular to the longitudinal direction L of the substrate 20.

[0057] Figure 2A , 2B Figure 2C illustrates processing step Z, in which the coated semi-finished product 100 is processed or manufactured, for example by stretching or profile rolling with a sliding action. During stretching with a sliding action, the substrate 100 is pulled through opening 91, see also... Figure 6 .

[0058] The opening 91 may be part of a drawing die 90, which includes openings 91 of different sizes to enable several drawing steps to be performed consecutively. Each opening 91 may be funnel-shaped to allow drawing to be performed easily by sliding action.

[0059] The height 80 of the substrate 20 is reduced by stretching through a sliding action. In the case of wire 100, the height 80 corresponds to the diameter 70.

[0060] like Figure 6 As shown, a first diameter 71 is provided before the stretching step, and a second diameter 72 smaller than the first diameter 71 is provided after the stretching step. Stretching by sliding action can cause the semi-finished product 100 to elongate in the longitudinal direction L. Figure 7 The image shown is a microscopic image of the partially stretched semi-finished product 100.

[0061] When the material is stretched through the opening 91 by sliding action, mechanical pressure is applied to the substrate 20, and particularly to the coating 30. This has a particularly positive effect on the properties of the coating 30.

[0062] Stretching via sliding is a special forming method. Another embodiment of forming can be profile roll forming. In this forming process, a force is applied to the coating 30 in the direction opposite to the coating direction S. The coating 30 is thus formed and its properties are altered.

[0063] Figure 3A , 3BExamples of coating step B are shown in Figures 3C and 3D. Alternating layers 39 of different materials are applied to the substrate 20. The material of the first layer 31 is different from the material of the second layer 32 applied on top of the first layer 31. The third layer 33 applied on top of the second layer 32 can be made of a different material than the materials of the first layer 31 and the second layer 32, or it can be made of the same material as the first layer 31. This process can be repeated until the desired number of layers 39 are obtained. Repeating sequences of different materials can be applied, such as alternating layer sequences ABABAB… or three repeating layers ABCABC-… Of course, other layer sequences can also be used, especially non-repeating layer sequences. Furthermore, it is conceivable, for example, that two consecutive layers are composed of the same material, such as AABAAB-… This is easier to manufacture in terms of process.

[0064] Coating step B produces coating 30, the thickness of which is 85 corresponding to the sum of the thicknesses of the individual layers 39, i.e., in the example shown, the sum of the thicknesses 81 of the first layer 31, 82 of the second layer 32, and 83 of the third layer 33. At least one of the layers 39 contains silver (Ag) or is composed entirely of silver.

[0065] Coating 30 may include other components, particularly at least one material selected from the group consisting of Ni (nickel), Pd (palladium), Ru (ruthenium), Ti (titanium), W (tungsten), Au (gold), Cu (copper), Fe (iron), Co (cobalt), or Mo (molybdenum). For example, layer 39 includes or is composed of such a material. In particular, these materials contribute to improved mechanical properties, such as hardness, for example, by hardening Ag.

[0066] exist Figure 4A , 4B In 4C, it can be seen how this coating 30 is altered by the forming process, particularly through stretching with a sliding action. The individual layers 31, 32, and 33 are mechanically mixed together by mechanical pressure. After stretching with a sliding action, the treated coating 38 can be understood as a single layer 39. In this case, the layer thickness 85 has been reduced. Figure 2A As shown in -C, the diameter 79 of the substrate 20 has also been reduced.

[0067] Stretching or profile rolling with a sliding action can cause the materials of the individual layers 31, 32, 33, 39 to be mixed and / or alloyed together. This mechanical alloying alters the properties of the coating 30. For example, the coating can then have a higher hardness than each individual component of the untreated coating 30.

[0068] The processed semi-finished product 100 may have forming marks, particularly from stretching or profile rolling with a sliding action. For example, the cross-section of the semi-finished product 100 may correspond to the opening 91. Furthermore, grooves or wavy shapes may exist along the longitudinal direction L, which may originate, for example, from small protrusions in the opening or may be intentionally introduced.

[0069] exist Figure 5 Another configuration is shown where coating 30 does not include different layers 39, but particles 40 are embedded in a single layer 39. Layer 39 may again include Ag, particularly as a matrix, i.e., as a base material or basic structure. Particles 40 may include other materials that may have properties such as reducing friction. Particles 40 may include or be composed of materials selected from the group consisting of graphene, graphite, carbon nanotubes, sulfides, sulfur sulfides, molybdenum sulfide, PTFE (polytetrafluoroethylene), tungsten sulfide, or hexagonal boron nitride.

[0070] For example, particles 40 can be introduced into coating 30 during coating step B. If coating 30 is produced by immersion or electroplating, particles 40 can be provided in a liquid and can be randomly deposited. The concentration of particles 40 in the coating can be controlled, for example, by the concentration of particles 40 in the liquid.

[0071] The particles 40 can be asymmetrical or symmetrical, sheet-like, strip-like, or linear. The forming process Z, particularly stretching or profile rolling, can advantageously alter the orientation of the particles 40. For example, in a linear configuration, the longitudinal direction of the line can be oriented parallel to the longitudinal direction L of the semi-finished product 100, along which rolling or stretching motions occur. Therefore, in particular, the surface 50 of the semi-finished product 101 can be largely formed by the surface of the particles 40. Consequently, the coefficient of friction can be very low.

[0072] In sheet-like or strip-like structures, stretching can alter the orientation of the particles 40, causing their surfaces to lie on the surface 50 of the semi-finished product. This also results in the surface properties of the semi-finished product 100 being largely determined by the properties of the particles 40, such as sliding properties.

[0073] Particle 40 may be spherical before processing. Through a shaping processing step Z, particle 40 may be flattened and / or stretched, and have flat sides oriented toward or adjacent to surface 50.

[0074] Furthermore, the forming process Z can increase the concentration of particles 40 on surface 50. This also positively affects the properties of the semi-finished product 100.

[0075] exist Figure 8 and Figure 9The image shows a microscopic image of a cross-section of a semi-finished product 100 in the form of wire 101, after coating step B but before processing step Z. In addition to the substrate 20 made of steel and the coating 30, an intermediate layer 25 is provided, which contains copper and can be used to conduct current and / or allow the coating 30 to adhere to the substrate 20. Generally, at this stage, the wire 101 has a diameter of approximately 0.5 mm. Figure 9 As shown, coating 30 comprises several individual layers 39. Relatively thick Ag layers 30 and 33 alternate with thinner palladium (Pd) layers 32 and 34.

[0076] The alloy content of other components in the coating, such as palladium, can be 0.3-15%, preferably 0.5-10%. This can result in the coating having particularly preferred properties, especially mechanical properties.

[0077] exist Figures 10 to 12 The image shows wire 101 after processing step Z. It now has a diameter of approximately 0.3 mm. Specifically, in Figure 12 As can be seen, in the region of coating 30 where there is high mechanical stress, Ag and Pd are mechanically alloyed, see region 65.

[0078] Microcrystal 60 can also be seen. Stretching can change the coating 30, causing microcrystal 60 to be predominantly on one or two crystal planes, for example, in <111> Crystal facet or <110> The crystal plane terminates at surface 50°. This can also have a positive impact on performance.

[0079] Figure 13 A contact element 200, which can be made from wire 101, is shown. Individual segments of wire 101 are bent and connected to form tapered receptacles for mating contact elements. Processing steps, particularly stretching or rolling steps, specifically alter frictional properties, such as the coefficient of friction or hardness. This can extend the service life of such contact element 200.

[0080] Figure Labels

[0081] 20 matrix

[0082] 25 intermediate layers

[0083] 30 coatings

[0084] 31 First Floor

[0085] 32 Second layer

[0086] 33 Third Floor

[0087] 34 Fourth Floor

[0088] 38-treated coating

[0089] 39th floor

[0090] 40 pieces

[0091] 50 surface

[0092] 60 microcrystals

[0093] Area 65

[0094] 70 diameter

[0095] 71 First Diameter

[0096] 72 Second Diameter

[0097] 79mm diameter matrix

[0098] 80 height

[0099] 81. Thickness of the first layer

[0100] 82. Layer thickness of the second layer

[0101] 83. Thickness of the third layer

[0102] 84. Layer thickness of the fourth layer

[0103] 85 coating thickness

[0104] 90 stretching die

[0105] 91 opening

[0106] 100 semi-finished products

[0107] 101 wire

[0108] 200 contact element

[0109] B Coating Step

[0110] L longitudinal direction

[0111] R radial direction

[0112] S-coating direction

[0113] U-shaped direction

[0114] Z Processing Steps

Claims

1. A method for processing a semi-finished product (100) for use in an electrical contact element (200), wherein, In the coating step (B), a coating is applied to a conductive substrate (20) along the coating direction (S), the coating comprising Ag as a matrix, wherein, in the processing step (Z) following the coating step (B), the coating (30) is processed by stretching with a sliding action through an opening (91) or by profile rolling.

2. The method according to claim 1, wherein, The coating (30) includes at least one additional component; The at least one additional component comprises, or is composed of, at least one material selected from the group consisting of Ni, Pd, Ru, Ti, Mo, W, Au, and Cu; or The at least one additional component comprises, or is composed of, at least one material selected from the group consisting of graphene, graphite, carbon nanotubes, sulfides, sulfur sulfides, molybdenum sulfide, tungsten sulfide, hexagonal boron nitride, and PTFE; or The at least one additional component is embedded in the Ag layer as particles (40).

3. The method according to claim 1 or 2, wherein, The semi-finished product (100) is wire (101).

4. The method according to claim 2, wherein, Ag and at least one other component were applied in alternating layers (31, 32, 33, 34, 39).

5. The method according to claim 2, wherein, Ag and the at least one other component are alloyed by stretching or profile rolling with a sliding action.

6. The method according to claim 2, wherein, When the at least one additional component is embedded in the Ag layer as particles (40), the particles (40) are given a specific orientation by stretching or profile rolling with a sliding action, or the specific orientation of the particles (40) is changed.

7. A semi-finished product (100) for an electrical contact element (200), wherein, The semi-finished product (100) includes a conductive substrate (20) and a coating (30) on the substrate (20), wherein the coating includes Ag as a matrix and the coating is altered by stretching or profile rolling with a sliding action.

8. The semi-finished product (100) according to claim 7, wherein, The coating (30) includes at least one additional component; The at least one additional component comprises, or is composed of, at least one material selected from the group consisting of Ni, Pd, Ru, Ti, Mo, W, Au, and Cu; or The at least one additional component comprises, or is composed of, at least one material selected from the group consisting of graphene, graphite, carbon nanotubes, sulfides, sulfur sulfides, molybdenum sulfide, tungsten sulfide, hexagonal boron nitride, and PTFE; or The at least one additional component is embedded in the Ag layer as particles (40).

9. The semi-finished product (100) according to claim 8, wherein, Ag and the at least one other component are mechanically alloyed by stretching or profile rolling with a sliding action.

10. The semi-finished product (100) according to any one of claims 7 to 9, wherein, At the surface (50) of the semi-finished product (100), the microcrystals (60) mainly terminate at one or two crystal planes.

11. The semi-finished product (100) according to claim 10, wherein, At the surface (50) of the semi-finished product (100), the microcrystals (60) mainly terminate at <111> Crystal planes and / or <110> Crystal facets.

12. The semi-finished product (100) according to claim 8, wherein, The alloy content of at least one additional component in the coating (30) is 0.3-15%.

13. An electrical contact element (200) comprising at least one semi-finished product (100) according to any one of claims 8 to 12.

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