Electrical connector

Abstract

The invention relates to an electrical connector (1), in particular an electrical connector, comprising a terminal part (1a) and a coupling part (1b), each having a metallic contact area (2, 2'), wherein the terminal part (1a) can be electrically connected to the coupling part (1b) via the metallic contact areas (2, 2'), and wherein at least one of the metallic contact areas (2, 2') has at least a partial coating system (3) applied by a PVD process. The coating system (3) comprises - a first layer (3a) of titanium or chromium arranged in the metallic contact area (2, 2'), and - at least one second layer (3b) arranged on the first layer (3a), which is formed either of carbon-doped titanium and / or chromium or alternatively of a carbide comprising titanium carbide and / or chromium carbide, and at least one third layer (3c) arranged on the at least one second layer (3b) of a hydrogen-free tetrahedral amorphous carbon with a sp 3 -Proportion of greater than 50% as bond type, which is undoped or has a doping of at least one element of the group comprising copper, tungsten, molybdenum, chromium, silver, titanium, iridium, gold, silicon, in a concentration in the range of 2 to 30 at%.

Description

[0001] The invention relates to an electrical connector, in particular an electrical connector, comprising a connecting part and a coupling part, each having a metallic contact area, wherein the connecting part can be electrically connected to the coupling part via the metallic contact areas, and wherein at least one of the metallic contact areas has at least partially a layer system applied by means of a PVD process.

[0002] Electrical connectors of the type mentioned above are known; see, for example, WO 2007 / 096 485 A2. There, surfaces of metallic products, such as electrical connectors, are coated by a laser beam evaporation process using a pulsed laser. The coating can be single-layer or multi-layered. Suitable materials for the coating include metals, metal oxides, metal nitrides, metal carbides, or mixtures thereof. Alternatively, the coating can consist of a carbon material with a carbon content exceeding 90 atm% and a sp 3 -Proportion greater than 70% as the bonding type of the coating.

[0003] The object of the invention is to provide further electrical connectors which, in addition to high electrical conductivity, also meet high requirements for electrochemical stability.

[0004] The task is for the electrical connector comprising a connecting part and a coupling part, each having a metallic contact area, wherein the connecting part can be electrically connected to the coupling part via the metallic contact areas, and wherein at least one of the metallic contact areas has at least partially a layer system applied by means of a PVD process (= physical vapor deposition), wherein the layer system - comprises a first layer of titanium or chromium arranged in the metallic contact area, and - comprising at least one second layer arranged on the first layer, which is formed either of carbon-doped titanium and / or chromium or alternatively of a carbide comprising titanium carbide and / or chromium carbide, and - arranged on at least one second layer, at least one third layer of hydrogen-free tetrahedral amorphous carbon (ta-C) with a sp 3 -Comprising a proportion greater than 50% as a bonding type which is undoped or has a doping of at least one element from the group comprising copper, tungsten, molybdenum, chromium, silver, titanium, iridium, gold, silicon, in a concentration in the range of 2 to 30 at%.

[0005] A “hydrogen-free” third layer is one that contains hydrogen in a proportion of no more than 3 at%.

[0006] In particular, the electrical connector is an electrical connector. Preferably, an electrical connector comprises a current-carrying busbar as its connection element, especially for implementing a low-voltage connection. Furthermore, an electrical connector in the form of a high-voltage connector, here for currents of at least 100 A, is preferred. Such high-current connectors are particularly used for high-voltage battery chargers in the automotive sector.

[0007] Such electrical connectors or electrical plug connectors according to the invention are suitable to withstand a large number of insertion and removal operations, even in contact with corrosive media and under weather conditions.

[0008] Preferred physical deposition processes or PVD processes for forming the layer system include arc evaporation and / or sputtering and / or high-performance pulse magnetron sputtering (HIPIMS).

[0009] The first layer serves in particular as an adhesion promoter layer for the metallic contact area. The first layer has a thickness in the range of 30 to 100 nm, preferably 60 nm.

[0010] The inclusion of at least one additional second layer and at least one additional third layer combines the advantages of high mechanical stability, excellent corrosion protection, and very high electrical conductivity, while being significantly more economically attractive than established precious metal-based solutions. A further advantage of the at least one third layer is its good sliding properties. The third layer thus possesses outstanding tribological properties, as it reduces friction and exhibits high wear resistance.

[0011] These properties increase the mechanical stability and thus the longevity of the electrical connector, especially with a large number of mating operations, while ensuring that the high electrical conductivity is maintained over a long period of time.

[0012] The at least one second layer has in particular a layer thickness in the range of 1 to 30 nm, preferably 10 nm.

[0013] The at least one third layer has in particular a layer thickness in the range of 30 to 300 nm, preferably 100 nm.

[0014] The at least one third layer is either an undoped top layer containing no dopant elements other than carbon (except for unavoidable manufacturing-related impurities such as nitrogen, oxygen, etc.). Undoped ta-C layers exhibit high electrical conductivity combined with high wear resistance and thus high mechanical stability. Furthermore, such a layer is electrochemically stable.

[0015] Alternatively, the at least one third layer comprises a doping of at least one element from the group comprising copper, tungsten, molybdenum, chromium, silver, titanium, iridium, gold, and silicon, in a concentration in the range of 2 to 30 at%. This is particularly preferred if the electrical conductivity of a third layer is to be further increased.

[0016] The metallic contact area is preferably formed from a material from the group comprising stainless steel, such as grades 1.4404 or DC04, as well as aluminum, an aluminum alloy, or an alloy containing predominantly tin. Alternatively, the metallic contact area is formed from a material from the group comprising copper, a copper alloy, nickel, a nickel alloy, or a low-alloy carbon steel. In particular, the metallic contact area is formed from copper or nickel. 100Cr6 has proven suitable as a low-alloy carbon steel.

[0017] A single second layer or multiple second layers can be applied on top of each other. These second layers can consist solely of carbon-doped titanium and / or chromium, or alternatively, solely of a carbide comprising titanium carbide and / or chromium carbide. Furthermore, the layer system can contain both carbon-doped titanium and / or chromium second layers and second layers comprising a carbide comprising titanium carbide and / or chromium carbide, which can also alternate.

[0018] Furthermore, a single third layer or several third layers can be applied on top of each other. This compensates for any layer defects that may occur during coating and eliminates points of attack for corrosive processes.

[0019] The metallic contact area is formed in particular in the form of a metal pin, a metal bracket, a metal strip, a metal sleeve, a metal sheet or a metal foil.

[0020] The following examples are intended to illustrate an electrical connector according to the invention, whereby doped or undoped third layers can be used: Example 1:

[0021] Metallic contact area: copper or nickel First layer: Titanium or chromium at least one second layer: carbon-doped titanium layer or TiC; at least one third layer: hydrogen-free ta-C Example 2:

[0022] Metallic contact area: copper or nickel First layer: Titanium or chromium at least one second layer: carbon-doped chromium layer or CrC; at least one third layer: ta-C hydrogen-free Example 3:

[0023] Metallic contact area: copper or nickel First layer: Titanium or chromium at least one second layer: carbon-doped titanium-chromium layer or TiCrC; at least one third layer: ta-C hydrogen-free Example 4:

[0024] Metallic contact area: Aluminum or stainless steel First layer: Titanium or chromium at least one second layer: carbon-doped titanium layer or TiC; at least one third layer: hydrogen-free ta-C Example 5:

[0025] Metallic contact area: Aluminum or stainless steel First layer: Titanium or chromium at least one second layer: carbon-doped chromium layer or CrC; at least one third layer: ta-C hydrogen-free Example 6:

[0026] Metallic contact area: Aluminum or stainless steel First layer: Titanium or chromium at least one second layer: carbon-doped titanium-chromium layer or TiCrC; at least one third layer: ta-C hydrogen-free

[0027] The Fig. Figures 1 to 4 show an example of an electrical connector comprising a terminal and a coupling. Thus, it shows Fig. 1 an electrical connector comprising a connector part and a coupling part in three-dimensional view; Fig. 2 the connecting part according to Fig. 1 in three-dimensional view in the area of ​​the enlarged metallic contact area; Fig. 3 the metallic contact area according to Fig. 2 in the cross-sectional view; and Fig. 4 an enlarged section of another metallic contact area in the cross-sectional view.

[0028] Fig. Figure 1 schematically shows an electrical connector 1 in the form of a plug connector comprising a terminal part 1a and a coupling part 1b. The terminal part 1a has two metallic contact areas 2 in the form of metal pins. The coupling part 1b also has two metallic contact areas 2' in the form of metal sockets. The metal pins can be inserted into the metal sockets, forming an electrically conductive connection between the terminal parts 4a and 4b, here in the form of electrical cables. A layer system 3 is formed on the metal pins and / or inside the metal sockets (see Figure 1). Fig. 2.

[0029] Fig. Figure 2 shows the connection part 1a according to Fig. 1. Three-dimensional view in the area of ​​the enlarged metallic contact area. 2. Same reference numerals as in Fig. 1 denote identical elements. The metallic contact area 2 in the form of a metal pin is covered at its end with a layer system 3 formed by a PVD process, wherein a third layer 3c forms a cover layer.

[0030] Fig. Figure 3 shows the metallic contact area 2 according to Fig. 2 in the cross-sectional view. The metallic contact area 2 is covered at its end by the layer system 3.

[0031] Fig. Figure 4 shows an enlarged section of the metallic contact area 2 according to the cross-sectional view in Fig.3. The metallic contact area 2 is partially covered with a layer system 3. The layer system 3 comprises, on a surface 20 of the metallic contact area 2, a first layer 3a and at least one second layer 3b. At least one third layer 3c is formed on the at least one second layer 3b. The metallic contact area 2 is made of copper, nickel, or stainless steel; the first layer 3a is made of titanium or chromium; the second layer 3b is made of a carbon-doped titanium layer or a carbon-doped chromium layer; and the at least one third layer 3c is made of a hydrogen-free tetrahedral amorphous carbon with a sp 3 A proportion greater than 50% is formed as a bond type. This can be used undoped or with doping. Reference symbol list 1 electrical connector 1a Connection part 1b Coupling part 2, 2' metallic contact area 3-layer system 3a first layer 3b second layer 3c third layer 20 surface 4a, 4b electrical connectors

Claims

[1] Electrical connector (1), in particular electrical connector, comprising a terminal part (1a) and a coupling part (1b), each having a metallic contact area (2, 2'), wherein the terminal part (1a) can be electrically connected to the coupling part (1b) via the metallic contact areas (2, 2'), and wherein at least one of the metallic contact areas (2, 2') has at least partially a layer system (3) applied by means of a PVD process, wherein the layer system (3) - comprises a first layer (3a) of titanium or chromium arranged in the metallic contact area (2, 2'), and - comprising at least one second layer (3b) arranged on the first layer (3a), which is formed either of carbon-doped titanium and / or chromium or alternatively of a carbide comprising titanium carbide and / or chromium carbide, and at least one third layer (3c) arranged on the at least one second layer (3b), consisting of a hydrogen-free tetrahedral amorphous carbon with a sp 3 -Comprising a proportion greater than 50% as a bonding type which is undoped or has a doping of at least one element from the group comprising copper, tungsten, molybdenum, chromium, silver, titanium, iridium, gold, silicon, in a concentration in the range of 2 to 30 at%. [2] Electrical connector (1) according to claim 1, wherein the first layer (3a) is formed in a layer thickness in the range of 30 to 100 nm, in particular of about 60 nm. [3] Electrical connector (1) according to claim 1 or 2, wherein the at least one second layer (3b) is formed in a layer thickness in the range of 1 to 30 nm, in particular of about 10 nm. [4] Electrical connector (1) according to one of claims 1 to 3, wherein the at least one third layer (3c) is formed in a layer thickness in the range of 30 to 300 nm, in particular of about 100 nm. [5] Electrical connector (1) according to any one of claims 1 to 4, wherein the metallic contact area (2, 2') is formed from a material from the group comprising stainless steel, aluminium, an aluminium alloy, an alloy containing predominantly tin. [6] Electrical connector (1) according to any one of claims 1 to 4, wherein the metallic contact area (2, 2') is formed from a material from the group comprising copper, a copper alloy, nickel, a nickel alloy, low-alloy carbon steel. [7] Electrical connector (1) according to one of claims 1 to 6, comprising as a connection part a current-carrying busbar, in particular a low-voltage connection. [8] Electrical connector (1) according to any one of claims 1 to 6 in the form of a high-voltage connector, in particular for high-voltage battery chargers.

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