Conductive member, method of coating at least one conductive member, and apparatus for coating at least one conductive member

Abstract

The invention relates to an electrically conductive component, such as a bipolar plate, a half plate, an electrode and a gasket, comprising a metal component; an adhesion layer optionally formed on the metal component; and a carbon coating formed on the adhesion layer, if provided, or on the metal component; wherein the carbon coating comprises an amorphous, at least substantially hydrogen-free DLC layer and at least one nanocrystalline graphite component embedded in the amorphous, at least substantially hydrogen-free DLC layer; wherein the at least one nanocrystalline graphite component comprises two or more stacked layers; and wherein the nanocrystalline graphite component is aligned perpendicular and / or at least substantially perpendicular to an axis A defined by the interface between the carbon coating and the metal component or the interface between the carbon coating and the adhesion layer, if provided.

Description

Technical Field

[0001] This invention relates to a conductive component, such as a bipolar plate, half-plate, electrode, and gasket, comprising: a metal component; an adhesive layer optionally formed on the metal component; and a carbon coating formed on the adhesive layer (if provided) or on the metal component; wherein the carbon coating comprises: an amorphous, at least substantially hydrogen-free DLC layer and at least one nanocrystalline graphite component embedded in the amorphous, at least substantially hydrogen-free DLC layer; wherein the at least one nanocrystalline graphite component comprises two or more stacked layers; and wherein the at least one nanocrystalline graphite component is aligned perpendicular to and / or at least substantially perpendicular to an axis A defined by the interface between the carbon coating and the metal component or the interface between the carbon coating and the adhesive layer (if provided). The invention also relates to a method for coating at least one conductive component and an apparatus for coating at least one conductive component. Background Technology

[0002] The electrical industry, particularly the automotive industry, is seeking low-cost, high-efficiency, and high-volume solutions for developing and manufacturing electrical devices such as fuel cell stacks or batteries. One of the key components in a fuel cell stack is the bipolar plate (BPP). One of the key components in a battery is the electrode. Low-cost steel can be relatively easily mechanically formed into electrodes, or so-called half-plates, which have a good flow field (note that two welded half-plates constitute a bipolar plate, BPP). However, due to the harsh operating environment at low pH and voltage levels, a highly conductive and protective coating is required on the steel to provide a long fuel cell lifespan. Summary of the Invention

[0003] Therefore, an object of the present invention is to provide a conductive component with improved electrical properties, for example, for use in fuel cell stacks or batteries. Another object of the present invention is to provide a conductive component with improved mechanical properties. Another object of the present invention is to provide a conductive component with improved corrosion resistance. Another object of the present invention is to provide a conductive component with reduced contact resistance. Another object of the present invention is to provide a method for manufacturing such a conductive component and an apparatus for performing said method. Specifically, the method can be carried out in a short period of time to produce a large quantity of said component.

[0004] This problem is solved by the present invention by providing a conductive component according to claim 1.

[0005] Such conductive components, such as bipolar plates, half-plates, electrodes, and washers, include:

[0006] Metal component; uncoated metal component having a first side and a second side, the first side and the second side facing different directions, for example, opposite directions; An adhesive layer, optionally formed on at least one of a first side and a second side of the metal component; and A carbon coating is formed on at least one of a first side and a second side of an adhesive layer (if provided) or on at least one of a first side and a second side of a metal component; The carbon coating comprises an amorphous, at least substantially hydrogen-free DLC layer and at least one nanocrystalline graphite component embedded in the amorphous, at least substantially hydrogen-free DLC layer. At least one of the nanocrystalline graphite components comprises two or more stacked layers; and At least one of the nanocrystalline graphite components is aligned perpendicular to and / or at least substantially perpendicular to axis A defined by the interface between the carbon coating and the metal component or the interface between the carbon coating and the adhesive layer (if provided).

[0007] In this way, the carbon coating can be applied to the first side or the second side, or to both the first side and the second side.

[0008] The conductive components described herein are, for example, components of fuel cell stacks or batteries, characterized by reduced contact resistance (CR), such as interfacial contact resistance (ICR) or electrical contact resistance (ECR). The conductive components have improved conductivity and can therefore be used as any component required to efficiently conduct current from and / or to a power source. Furthermore, the conductive components described herein have improved mechanical stability and corrosion resistance, particularly against the chemical environment surrounding the conductive components during operation. Thus, particularly due to the multifunctional nature of the carbon coating described herein, the conductive components are associated with enhanced electrical performance throughout their extended lifespan. Non-limiting examples of conductive components are bipolar plates; half-plates; electrodes, such as electrodes in lithium (Li)-ion batteries; gaskets; or porous transport layers (PTLs), such as PTLs used in proton exchange membrane water electrolyzers (PEMWE).

[0009] The term "metal component" as used herein can refer to a component comprising or composed of at least a conductive metallic material. The metallic material may include stainless steel (SS), titanium (Ti), nickel (Ni), magnesium (Mg), niobium (Nb), and / or aluminum (Al), preferably aluminum, stainless steel (SS), or titanium (Ti), more preferably stainless steel (SS) or a combination thereof. The metallic component may be an alloy comprising at least one of the aforementioned metallic materials as a major component. As described herein, the major component constitutes at least 50% by mass of the total mass of the alloy, preferably at least 60%, 70%, 80%, or 90% by mass. For example, the metallic component may be a Ti alloy, such as Ti-Al6-V4. When the metallic component comprises or is composed of Ti, the excellent corrosion resistance of Ti eliminates the need for a deposited adhesion layer, thus simplifying the manufacture of such components. The metallic component may also comprise or be composed of aluminum, as aluminum is generally inexpensive and lightweight.

[0010] The “adhesive layer” described herein is optional. When used, it can be selected from any layer capable of providing improved adhesion between the carbon layer and the metal component. Furthermore, the adhesive layer preferably improves the corrosion resistance of the metal component. This may be necessary, for example, when the metal component comprises or is composed of a corrosive metal such as iron. As mentioned above, from a corrosion protection perspective, using a metal component comprising or composed of titanium can make the deposition of the adhesive layer unnecessary. Additionally, the adhesive layer can reduce the diffusion of ions from the conductive component into the environment surrounding it, which could lead to poisoning of systems including the conductive component (e.g., batteries, fuel cells, or flow batteries). Non-limiting examples of materials forming the adhesive layer are Group IV elements (Ti, Zr, and / or Hf), Group V elements (V, Nb, and / or Ta), and / or Group VI elements (Cr, Mo, and / or W). The material forming the adhesive layer can be a ceramic material, such as titanium nitride (TiN) or zirconium nitride (ZrN). The adhesive layer can be an adhesive multilayer, i.e., composed of at least two stacked adhesive layers as described above, such as an adhesive multilayer composed of a TiN layer and a Ti layer, wherein the TiN layer is stacked on top of the Ti layer, or vice versa.

[0011] The "carbon coating" (also referred to herein as a carbon layer) described herein is essential for the conductive components of this invention. When no adhesive layer is used, the carbon coating can be applied / deposited (i.e., coated) directly onto the surface of the metal component in the form of a layer. When an adhesive layer is used, the carbon coating can be applied / deposited (i.e., coated) onto the surface of an adhesive layer already deposited on the surface of the metal component. In other words, when an adhesive layer is used, the adhesive layer is disposed between the metal component and the carbon coating. The carbon coating is preferably a continuous carbon coating, i.e., a continuous carbon layer.

[0012] The “carbon coating” described herein comprises an amorphous, at least substantially hydrogen-free DLC layer and at least one nanocrystalline graphite component embedded (also referred to as “integrated,” “incorporated,” or “included”) within the amorphous, at least substantially hydrogen-free DLC layer. The use of a carbon coating ensures both the electrical performance of the active side of, for example, a bipolar plate, and the mechanical stability and durability of conductive components. In this regard, it should be noted that the carbon coating also provides reduced corrosion and lower contact resistance.

[0013] As used herein, the term "at least substantially hydrogen-free DLC layer" preferably refers to a DLC layer based on 100 at% containing less than 1 at% hydrogen, such as less than 0.8 at% or less than 0.5 at% hydrogen. The term "DLC" means "diamond-like carbon" and is well known to those skilled in the art.

[0014] As used herein, a “DLC layer that is at least substantially hydrogen-free” is amorphous. The amorphous, at least substantially hydrogen-free DLC layer preferably comprises an aC layer and / or a-C layer. The terms “aC layer” and “ta-C layer” are well known to those skilled in the art. An amorphous, at least substantially hydrogen-free DLC layer may be formed from a single amorphous, at least substantially hydrogen-free DLC layer. Alternatively, an amorphous, at least substantially hydrogen-free DLC layer may be formed from two or more amorphous, at least substantially hydrogen-free DLC layers. In the latter case, these layers are arranged one on top of the other, i.e., stacked. At least two DLC layers may be at least substantially the same (i.e., slightly different) or different from each other in terms of the absolute values ​​of the properties described herein. For example, an amorphous, at least substantially hydrogen-free DLC layer can be formed by an aC layer (first DLC layer) and a ta-C layer disposed on top of the aC layer (second DLC layer), i.e., the two DLC layers are different from each other, for example, in their dominant C-C bond type (hybridization type, sp). 2 and / or sp 3 The difference lies in the aspect of the amorphous, at least substantially hydrogen-free DLC layer. In another example, the amorphous, at least substantially hydrogen-free DLC layer can contain two aC layers, i.e., two identical stacked DLC layers. The latter term can be useful when only one of the two aC layers is embedded in the nanocrystalline graphite composition.

[0015] Preferably, the carbon coating described herein comprises or consists of at least one amorphous, at least substantially hydrogen-free DLC layer embedded with at least one nanocrystalline graphite component. In a preferred embodiment, the carbon coating comprises or consists of two or more amorphous, at least substantially hydrogen-free DLC layers, wherein each of the amorphous, at least substantially hydrogen-free DLC layers is embedded with at least one nanocrystalline graphite component.

[0016] The “nanocrystalline graphite composition” (also referred to as “nanocrystalline graphite cluster” or “multilayer graphite cluster”) described herein comprises stacked layers of two or more carbon-based planar surfaces. The nanocrystalline graphite composition is uniformly distributed throughout the amorphous, at least substantially hydrogen-free DLC layers. The nanocrystalline graphite composition can be considered spatially isolated from each other, while being electrically connected to each other, for example, via the surrounding amorphous, at least substantially hydrogen-free DLC layers. The stacked layers in the nanocrystalline graphite composition may have the same length or may not have the same length.

[0017] It is noteworthy that the nanocrystalline graphite component forms a single crystal and does not aggregate with another nanocrystalline graphite component (e.g., it does not aggregate into spheres or any other shape). The nanocrystalline graphite component is single-crystal graphite (also known as a "single-crystal structure"). On both the microscopic and macroscopic levels, "single-crystal graphite" has an ordered and highly oriented graphite crystal structure (graphite clusters) in which carbon-based planes (such as graphene) are stacked.

[0018] Each stacked layer is a planar layer of carbon atoms, i.e., a carbon-based plane. In a single layer, carbon atoms can be arranged in a hexagonal or honeycomb lattice. The stacked layers are preferably graphene layers, or at least partially graphene layers.

[0019] The nanocrystalline graphite component is aligned perpendicular to and / or at least substantially perpendicular to axis A, which is defined by the interface between the carbon coating and the metal component or the interface between the carbon coating and the adhesive layer (if provided). In other words, each stacked layer forming the nanocrystalline graphite component is aligned perpendicular to and / or at least substantially perpendicular to axis A. In a preferred embodiment, the total amount of nanocrystalline graphite component embedded in an amorphous, at least substantially hydrogen-free DLC layer is aligned perpendicular to and / or at least substantially perpendicular to axis A. Axis A (see...) Figure 1The term "carbon coating" can be alternatively understood as being defined by the surface of a carbon coating opposite to the interface between the carbon coating and the metal component or the interface between the carbon coating and the adhesive layer (if provided). The nanocrystalline graphite component exhibits a high degree of order relative to axis A. Therefore, the orientation of the nanocrystalline graphite component relative to axis A is not random. This orientation can be determined by any suitable technique known to those skilled in the art, such as by means of TEM analysis (transmission electron microscopy). This highly ordered orientation of the nanocrystalline graphite component relative to axis A further enhances the conductivity of the conductive component described herein. In the conductive component described herein, current applied thereto can flow in a direction perpendicular to the interface (the interface between the carbon coating and the metal component or the interface between the carbon coating and the adhesive layer (if provided)), which is parallel or at least substantially parallel to the carbon-based plane (e.g., the graphene plane) in the nanocrystalline graphite component. In comparison, for example, in highly oriented pyrolytic graphite (HOPG), the conductivity parallel to the graphene plane (2e6 S / m) is 4000 times higher than that perpendicular to the graphene plane (5e2 S / m).

[0020] The present invention also relates to a method for coating at least one conductive component, particularly at least one conductive component according to the present disclosure, such as a bipolar plate, a half-plate, an electrode, a gasket, etc., the method comprising the following steps: - Provide an uncoated metal component; the uncoated metal component has a first side and a second side, the first side and the second side facing different directions, for example, opposite directions; - Etch at least one of the first and second sides of the uncoated metal component; - Optionally, an adhesion layer is deposited on at least one of the first and second sides of the etched, uncoated metal part using one of physical vapor deposition, arc physical vapor deposition, arc ion plating, sputtering, EBPVD (electron beam physical vapor deposition), or Hipims processes; and - Deposit a carbon coating on at least one of the first and second sides of the adhesive layer (if provided) or directly on at least one of the first and second sides of the etched uncoated metal part; A carbon coating is deposited at a bias voltage of -20 V to -400 V with a layer thickness selected from 5 nm to 300 nm by means of at least one of physical vapor deposition (PVD) processes (such as arc PVD), sputtering processes, arc ion plating processes, EBPVD (electron beam physical vapor deposition) processes and / or Hipims processes.

[0021] In this way, the carbon coating can be applied to the first side or the second side, or to both the first side and the second side.

[0022] This process allows conductive components (specifically, those with the carbon coating described herein) to be coated in a relatively short time, enabling mass production. Furthermore, this coating process allows for the creation of relatively low-cost conductive components.

[0023] Carbon coating processes can be performed using either in-line coating or batch coating processes.

[0024] The most common method for depositing carbon is sputtering (also known as sputter deposition), especially using unbalanced magnetron (UBM) sputtering setups. These are well-known methods for in-line or batch coating because sputtering offers good uniformity, controllability, and long target lifetime, which are typically required in industrial production, such as glass coating machines, PVD production lines for display glass coating, and roll-to-roll coating machines.

[0025] Furthermore, UBM provides a clean and smooth coating, free of any droplets from the target material. On the other hand, arc PVD and arc ion plating are both very fast deposition techniques, but because arc PVD used in this case is a point source rather than a linear source, it is more difficult to achieve robust industrial processing.

[0026] The machines are more complex and require greater design effort to deliver reliable, controlled, and uniform industrial processes. However, the final solution offers significantly higher productivity compared to more traditional UBM (Unified Product Manufacturing) technologies, thereby reducing the cost of ownership for users.

[0027] The etching step can be a plasma etching process and / or a metal ion etching process. Etching processes are typically used to remove oxide layers present on metal substrates. Oxide layers generally lead to reduced conductivity and decreased adhesion of carbon coatings. Therefore, to increase the conductivity of conductive components and the adhesion of carbon coatings to conductive components, it is necessary to remove this oxide layer.

[0028] The present invention also relates to an apparatus for coating at least one conductive component (such as one or more bipolar plates, one or more half-plates, one or more electrodes, one or more gaskets, etc.), particularly at least one conductive component according to the present disclosure, said apparatus being configured to perform the method according to the present disclosure, the apparatus being an in-line coating system comprising: - Multiple vacuum chambers, which are arranged in series in sequence; - One or more cathodes, the one or more cathodes being arranged in at least some of a plurality of vacuum chambers; and - One or more fixtures, each of which is configured to receive a plurality of uncoated metal parts, wherein a first outer surface and a second outer surface to be coated each face a cathode, the cathodes being cathodes for at least one of physical vapor deposition (PVD) processes (such as arc PVD), sputtering processes, arc ion plating processes, EBPVD (electron beam physical vapor deposition) processes and / or Hisims processes. The one or more fixtures are arranged to move linearly within and from a respective vacuum chamber, wherein each vacuum chamber is configured to perform a process, preferably a static process, selected from a group of members including: heating, evacuation, etching, cooling, deposition of an adhesion layer, carbon coating, removal, and / or combinations thereof. The cathodes in the vacuum chamber configured to perform the carbon coating process are arranged to be substantially parallel to each other.

[0029] In this device, the metal component to be carbon coated is arranged between cathodes. For example, the metal component can be sandwiched between two cathodes arranged opposite each other, i.e., the two cathodes are arranged parallel to each other.

[0030] Therefore, the cathode is arranged along the longitudinal axis of the in-line coating system without tilting. This arrangement has been found to provide a particularly advantageous type of conductive component.

[0031] The cathode can provide a linear carbon source (e.g. in a sputtering process) or a point carbon source (e.g., a cathode assembly for a point arc source).

[0032] In a preferred embodiment, two or more cathodes are used to deposit the carbon coating, with each cathode equipped with carbon. This allows for an increase in the thickness of the carbon coating. For example, the surface of a metal component optionally having an adhesive layer can be carbon-coated using three cathodes arranged sequentially. The surface of the metal component optionally having an adhesive layer can then have a carbon coating thickness three times greater than the surface of a metal component optionally having an adhesive layer that is carbon-coated using only one cathode. Of course, if desired, the same arrangement of one, two, or more cathodes can be additionally used for a second surface of the metal component optionally having an adhesive layer.

[0033] With the help of this device, the aforementioned conductive components can be coated with a durable coating.

[0034] Furthermore, this coating can be produced in online PVD coating systems with high throughput and attractive per-piece costs.

[0035] Furthermore, using Arc-PVD technology in an online system can increase coating speed compared to sputtering, thereby reducing equipment complexity and cost in industries such as automotive, construction, aerospace, stationary applications, heavy transportation, marine applications, and forklifts.

[0036] Preferred embodiments of the invention are described below: In a preferred embodiment, the total amount of at least one nanocrystalline graphite component is embedded in an amorphous, at least substantially hydrogen-free DLC layer.

[0037] In another preferred embodiment, the metal component has a first side and a second side, the first side and the second side facing different directions, preferably opposite directions; an adhesive layer is optionally formed on at least one of the first side and the second side of the metal component; a carbon coating is formed on the first side and the second side of the metal component and / or the adhesive layer (if provided). In other words, the metal component may be coated on two (2) or more of its sides (i.e., surfaces). Preferably, for example, in the case where the conductive component is a bipolar plate, the two (2) sides face opposite directions. It is also possible, for example, in the case where the conductive component is an electrode, that all surfaces of the metal component are coated as described herein.

[0038] In another preferred embodiment, the carbon coatings on the first side and the second side of the metal component are similar or different from each other, and the first and / or second sides of the metal component may optionally have an adhesion layer. For example, the carbon coatings on the first and second sides of the metal component may be similar or different from each other in the following aspects: the thickness of the carbon coatings; the composition of the amorphous, at least substantially hydrogen-free DLC layers (e.g., the type and number of DLC layers, sp...). 2 with sp 3 Hybridization ratio); the degree of embedding of nanocrystalline graphite components; orientation of nanocrystalline graphite components along axis A; etc.

[0039] In a preferred embodiment, the amorphous, at least substantially hydrogen-free DLC layer comprises one or more ta-C layers and / or one or more aC layers.

[0040] In another preferred embodiment, the sp of the amorphous, at least substantially hydrogen-free DLC layer 2 with sp 3 The content of sp is between 30% and 80%. 2within the range of 70% to 20% sp3. The ratio of sp2 to sp3 content in the amorphous, at least substantially hydrogen-free DLC layer may range from 30% sp2 / 70% sp3 to 80% sp2 / 20% sp3. In a more preferred embodiment, based on 100% of the amorphous, at least substantially hydrogen-free DLC layer, the sp of the amorphous, at least substantially hydrogen-free DLC layer 2 content is higher than 40% sp 2 , more preferably higher than 60%. These are beneficial properties of amorphous, at least substantially hydrogen-free DLC layers. The sp of the amorphous, at least substantially hydrogen-free DLC layer 2 and sp 3 content can be determined by any suitable technique known to those skilled in the art, for example by means of X-ray photoelectron spectroscopy (XPS).

[0041] In another preferred embodiment, based on 100at% of the amorphous, at least substantially hydrogen-free DLC layer, the amorphous, at least substantially hydrogen-free DLC layer is a DLC layer containing less than 1at% of hydrogen. The hydrogen content of the amorphous, at least substantially hydrogen-free DLC layer can be determined by any suitable technique known to those skilled in the art, for example by means of secondary ion mass spectrometry (SIMS).

[0042] In another preferred embodiment, the at least one nanocrystalline graphite component comprises two (2), three (3), four (4), five (5), ten (10), fifteen (15) or more stacked layers. That is, each of the at least one nanocrystalline graphite component may be formed of two (2), three (3), four (4), five (5), ten (10), fifteen (15) or more stacked layers. In a more preferred embodiment, the at least one nanocrystalline graphite component comprises three (3) or more stacked layers. It is noted that in the same DLC layer, the nanocrystalline graphite components may have the same number and / or different numbers of stacked layers. For example, the DLC layer may comprise an amount X of nanocrystalline graphite components having three (3) stacked layers, and an amount Y of nanocrystalline graphite components having five (5) stacked layers, wherein X<Y. The number of stacked layers of the nanocrystalline graphite component is preferably in the range of 2 to 100, and more preferably in the range of 2 to 80, 2 to 60, 2 to 50, 2 to 30, 2 to 20, 2 to 15, 2 to 10 and / or 2 to 5. The number of stacked layers of the nanocrystalline graphite component can be determined by any suitable technique known to those skilled in the art, for example by means of TEM analysis (transmission electron microscopy analysis). The nanocrystalline graphite components having the number of stacked layers as described above can form a uniform distribution throughout the amorphous, at least substantially hydrogen-free DLC, thereby enhancing the electrical conductivity of the conductive member.

[0043] In another preferred embodiment, at least one nanocrystalline graphite component has an aspect ratio of 1:1 to 1:20. In a more preferred embodiment, at least one nanocrystalline graphite component has an aspect ratio of 1:5, 1:1.1, or 1:1. The aspect ratio is determined from a side view of the nanocrystalline graphite component (i.e., observing the total number of stacked layers forming the nanocrystalline graphite component). As used herein, “aspect ratio” is defined as the ratio of the length (L) to the width (W) of the nanocrystalline graphite component, where the length (L) ≥ the width (W). Given that the length (L) ≥ the width (W), the length (L) of the nanocrystalline graphite component can be defined as the sum of the interlayer distances between the total number of stacked layers forming the nanocrystalline graphite component. For example, a nanocrystalline graphite component formed by eight (8) stacked layers, each stacked layer having an interlayer distance of 0.32 nm from its adjacent layers, can have a length (L) of approximately 2.24 nm (7 x 0.32 nm). Given a length (L) ≥ width (W), the width (W) of the nanocrystalline graphite component can be defined by the width of the widest stacked layer in the nanocrystalline graphite component. The length (L), width (W), and aspect ratio of the nanocrystalline graphite component can be determined by any suitable technique known to those skilled in the art, such as by means of TEM analysis (transmission electron microscopy). Nanocrystalline graphite components with the aspect ratio described above can form a uniform distribution throughout the amorphous, at least substantially hydrogen-free DLC, thus enhancing the conductivity of the conductive component.

[0044] In another preferred embodiment, the stacked layers of the nanocrystalline graphite composition have a layer spacing of about 0.1 nm to about 2 nm, preferably about 0.2 nm to about 0.6 nm, and more preferably about 0.3 nm (meaning approximately ±0.05 nm). The layer spacing is the distance between two adjacent layers in the nanocrystalline graphite composition. A layer spacing of about 0.3 nm corresponds to the lattice spacing of the graphite (0002) plane. The layer spacing can be measured by any suitable method known to those skilled in the art, such as by using TEM. This spacing has been found to provide particularly advantageous nanocrystalline graphite compositions.

[0045] In another preferred embodiment, the nanocrystalline graphite component aligned at least substantially perpendicular to axis A is a nanocrystalline graphite component tilted at ±30 degrees or less relative to axis P perpendicular to axis A. In a more preferred embodiment, the tilt is ±20 degrees or less, ±15 degrees or less, ±10 degrees or less, or ±5 degrees or less. These tilt angles prevent random orientation of the nanocrystalline graphite component along axis A. The nanocrystalline graphite component is perpendicular to axis A and / or at least substantially perpendicular to axis A. The latter (substantially perpendicular) means that the nanocrystalline graphite component is tilted at ±70 degrees or more relative to axis A, i.e., tilted at ±30 degrees or less relative to axis P perpendicular to axis A (see [link to relevant documentation]). Figure 11 Therefore, the carbon coating of the present invention described herein can have a series of nanocrystalline graphite components, some of which are aligned perpendicular to axis A, some of which are tilted ±30 degrees relative to axis P, some of which are tilted ±15 degrees relative to axis P, and so on. This highly ordered orientation of the nanocrystalline graphite components relative to axis A further enhances the conductivity of the conductive components described herein.

[0046] In another preferred embodiment, based on the total amount of carbon coating (100%), the ratio of the amount of amorphous, at least substantially hydrogen-free DLC layer to the amount of at least one nanocrystalline graphite component ranges from 20% to 90%. In a more preferred embodiment, the ratio ranges from 40% to 80%, and even more preferably from 30% to 70%. Such a ratio has been found to provide a particularly beneficial carbon coating for conductive components in terms of improved conductivity and reduced contact resistance.

[0047] In another preferred embodiment, the thickness of the carbon coating is 5 to 300 nm. In a more preferred embodiment, the thickness is in the range of 15 nm to 150 nm. In even more preferred embodiments, the thickness is in the range of 25 nm to 100 nm. This carbon coating has been found to be mechanically stable and also resistant to chemical environments, such as those present in fuel cell stacks.

[0048] In another preferred embodiment, the conductive component includes an adhesive layer comprising at least one material selected from the group consisting of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, nickel, cobalt, magnesium, gadolinium, nitrogen, carbon, boron, aluminum, and combinations thereof. In a more preferred embodiment, the adhesive layer comprises or is composed of titanium. These materials have been found to provide particularly advantageous types of adhesive layers.

[0049] In another preferred embodiment, the amorphous, at least substantially hydrogen-free DLC layer is 100 at%, and the argon content of the amorphous, at least substantially hydrogen-free DLC layer is less than 5 at%. In a more preferred embodiment, the argon content is less than 2 at%, more preferably less than 1 at%. For example, the sputtered carbon coating based on the amorphous, at least substantially hydrogen-free DLC layer of 100 at% can have an argon content of 2 at%. The carbon coating formed by the arc PVD process based on the amorphous, at least substantially hydrogen-free DLC layer of 100 at% can have an argon content of less than 2 at%. Carbon coatings including such amorphous, at least substantially hydrogen-free DLC layer can have enhanced quality, for example, due to improved corrosion stability.

[0050] In another preferred embodiment, the amorphous, at least substantially hydrogen-free DLC layer is 100 at%, and the iron content of the amorphous, at least substantially hydrogen-free DLC layer is less than 5 at%. In a more preferred embodiment, the iron content is less than 1 at%, and even more preferably less than 0.1 at%. The carbon coating including such an amorphous, at least substantially hydrogen-free DLC layer can have enhanced quality for the applications described herein.

[0051] In another preferred embodiment, the contact resistance (CR) of the conductive component measured at a contact pressure of 1 MPa is 0.01 Ω·cm² or less. In a more preferred embodiment, the contact resistance measured at a contact pressure of 1 MPa is 0.008 Ω·cm² or less, 0.005 Ω·cm² or less, or 0.003 Ω·cm² or less. The lower limit may be 0.001 Ω·cm² or greater measured at a contact pressure of 1 MPa. Depending on the application of the conductive component, CR may be ICR (interfacial contact resistance, e.g., in a fuel cell) or ECR (electrical contact resistance, e.g., in a battery). Conductive components with such contact resistance have been found to have particularly advantageous electrical properties.

[0052] In this document, all preferred embodiments and features described above or in the claims for the conductive component itself are applicable to the method of coating at least one conductive component, with necessary modifications.

[0053] According to another aspect, the present invention relates to a method for coating at least one conductive component, particularly at least one conductive component according to the present disclosure, such as a bipolar plate, half-plate, electrode, gasket, etc.

[0054] In a preferred embodiment, the uncoated metal component has a first side (i.e., a first surface) and a second side (i.e., a second surface) facing different directions, such as opposite directions; the first and second sides of the uncoated metal component are etched; at least one of the etched first and second sides of the uncoated metal component is optionally deposited with an adhesive layer; and the first and second sides having an adhesive layer (if provided) and / or the etched first and second sides are deposited with a carbon coating. In other words, the uncoated metal component may be coated on two (2) or more of its sides (i.e., surfaces). Preferably, for example, in the case where the conductive component is a bipolar plate, the two (2) sides facing opposite directions are coated. It is also possible, for example, in the case where the conductive component is an electrode, that all surfaces of the metal component are coated as described herein.

[0055] In another preferred embodiment, during the carbon coating step, the metal component and the adhesive layer (if provided) undergo continuous (i.e., stable) heating. This heating essentially originates from the evaporation of carbon at the cathode during the carbon coating step, which forms ions and transfers to the metal component and the adhesive layer (if provided), resulting in heating of the metal component and the adhesive layer (if provided). In other words, during the carbon coating step, the metal component and the adhesive layer (if provided) have a continuous (i.e. stable) temperature gradient generated by said heating. As used herein, the term "continuous temperature gradient" should be understood as a uniform temperature distribution throughout the metal component, which optionally has an adhesive layer, during the carbon coating step, as used herein. In the case where the metal component and the adhesive layer (if provided) undergo continuous carbon coating steps on each side, i.e., carbon is applied to the first side of the metal component and the adhesive layer (if provided) and then to the second side, the heating and the resulting temperature gradient may be unstable or discontinuous.

[0056] In another preferred embodiment, the etching step includes a plasma etching process, preferably an argon plasma etching process, performed over a time period ranging from 0.1 minutes to 60 minutes, specifically from 0.5 minutes to 5 minutes, wherein the bias voltage is in the range of -50 V to -1200 V, preferably in the range of -150 V to -350 V. The plasma etching process may be necessary where it is necessary to reduce or avoid oxide layers on the surface of the metal component. The plasma etching process described above can reduce the surface of a metal component that may include an oxide layer by about 20 nm (at least 10 nm). Etching away the oxide layer can reduce the ICR, but it also reduces the adhesion of the adhesion layer (if provided). In a more preferred embodiment, the plasma etching process is an argon plasma etching process, and the bias voltage is between -150 V and -350 V.

[0057] In another preferred embodiment, the etching step includes a metal ion etching process performed over a time period ranging from 0.1 minutes to 60 minutes, specifically from 0.5 minutes to 5 minutes, wherein the bias voltage is in the range of -50 V to -1200 V, preferably in the range of -600 V to -1200 V. The metal ion etching process may be necessary where it is necessary to reduce or avoid oxide layers on the surface of the metal component. The metal ion etching process described above can reduce the surface area of ​​a metal component that may include an oxide layer by approximately 20 nm (at least 10 nm). Etching away the oxide layer can reduce the ICR and increase the adhesion of the adhesion layer (if provided).

[0058] In another preferred embodiment, the bias voltage during the etching step (e.g., a plasma etching process or a metal ion etching process) includes DC, unipolar, and / or bipolar.

[0059] In another preferred embodiment, the method further includes the step of depositing an adhesion layer, wherein said step includes depositing an adhesion layer with a thickness in the range of 25 nm to 500 nm under a bias voltage in the range of -0 V to -350 V. In a more preferred embodiment, the thickness of the adhesion layer is in the range of 30 nm to 300 nm, even more preferably in the range of 40 nm to 200 nm, 50 nm to 150 nm, and even more preferably in the range of 50 nm to 100 nm. For example, when the adhesion layer comprises titanium, which typically has high corrosion resistance, choosing a smaller thickness (e.g., 100 nm (±5 nm)) may be sufficient. This can also be cost-effective.

[0060] In another preferred embodiment, the method further includes the step of depositing an adhesion layer, wherein the adhesion layer is deposited using an arc PVD process. In a more preferred embodiment, the bias voltage is in the range of -20 V to -400 V.

[0061] In another preferred embodiment, the method further includes the step of depositing an adhesion layer, wherein a sputtering process and / or a HIPIMS process is used to deposit the adhesion layer. In a more preferred embodiment, the bias voltage is in the range of -20 V to -350 V.

[0062] In another preferred embodiment, the method further includes the step of depositing an adhesion layer, wherein the adhesion layer comprises at least one of Ti, Cr, V, Ta, Ni, Co, Nb, Mg, B, Gd, Zr, TiN, CrN, NbN, ZrN, and combinations thereof. In a more preferred embodiment, the adhesion layer comprises Ti and / or Cr due to its high corrosion resistance.

[0063] In another preferred embodiment, the carbon coating comprises an amorphous, at least substantially hydrogen-free DLC layer and at least one nanocrystalline graphite component embedded in the amorphous, at least substantially hydrogen-free DLC layer.

[0064] In another preferred embodiment, the amorphous, at least substantially hydrogen-free DLC layer comprises a top layer in which dopants are present, or comprises dopants throughout the amorphous, at least substantially hydrogen-free DLC layer. It has been found that the use of dopants provides highly beneficial carbon coatings in terms of their electrical properties, corrosion resistance, and mechanical stability (specifically at higher voltages).

[0065] In another preferred embodiment, the dopant is selected from the group consisting of: titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, nitrogen, boron, silicon, and combinations thereof. In a more preferred embodiment, the dopant is boron and / or silicon. For example, using boron as a dopant can increase thermal resistance and conductivity while reducing the internal stress of the conductive components described herein.

[0066] In another preferred embodiment, the amorphous, at least substantially hydrogen-free DLC layer comprises 100 at% or a top layer of the amorphous, at least substantially hydrogen-free DLC layer including dopant comprises 100 at%, with the percentage of dopant ranging from 0.2 at% to 10 at%. In a more preferred embodiment, the amorphous, at least substantially hydrogen-free DLC layer comprises 100 at% or a top layer of the amorphous, at least substantially hydrogen-free DLC layer including dopant comprises 100 at%, with the percentage of dopant ranging from 0.5 at% to 6 at%. In even more preferred embodiments, the percentage of dopant ranges from 2 at% to 4 at%.

[0067] In another preferred embodiment, the method is carried out in a vacuum chamber (such as the vacuum chamber of an in-line coating system or a batch coating system), and during the carbon coating deposition step, the temperature of the metal component is adjusted to a range of 100°C to 450°C, specifically 250°C to 450°C. In this way, a particularly hard and durable layer structure can be formed. Furthermore, the growth of the nanocrystalline graphite component described herein can be further enhanced.

[0068] In another preferred embodiment, the carbon coating is deposited with a layer thickness ranging from 5 nm to 300 nm. In even more preferred embodiments, the carbon coating is deposited with a layer thickness ranging from 15 nm to 150 nm, 25 nm to 100 nm, or 40 nm to 80 nm. Such carbon coatings have been found to be mechanically stable and also resistant to the chemical environments present in operating systems (e.g., batteries or fuel cell stacks).

[0069] In another preferred embodiment, the carbon coating is deposited under a bias voltage ranging from -20 V to -400 V. This carbon coating has been found to be mechanically stable and also resistant to the chemical environments present in operating systems (e.g., batteries or fuel cell stacks).

[0070] In another preferred embodiment, the carbon coating is deposited using an arc physical vapor deposition process or an arc ion plating process, wherein the arc cathode current is preferably in the range of 40 A to 150 A, more preferably in the range of 40 A to 90 A. These ranges are typically used for circular point sources with a target diameter of 102 mm. Using a higher current than described above can lead to overheating, thus reducing the effectiveness of the conductive components described herein.

[0071] In another preferred embodiment, the carbon coating is deposited using a HIPIMS process, wherein the target density is 70 Watt / cm² or higher. In a more preferred embodiment, the target density is 100 Watt / cm² or higher, 150 Watt / cm² or higher, or 200 Watt / cm² or higher. For example, the power intensity in the HIPIMS process can be 220 W / cm² (target size 12.5 cm x 99.1 cm), and the peak pulse during ta-C can be 272 kW, wherein the carbon target power is 12 kW.

[0072] One or more cathodes can be provided for coating at least one conductive component, wherein the cathodes can be arranged on one or more sides of the coating chamber. In this way, one or more conductive components can be coated in batches or in a continuous process from one side or from both sides simultaneously.

[0073] One of the arc deposition process and the HIPIMS process can be used to coat at least one conductive component. This process can achieve particularly good carbon coatings that adhere better to at least one conductive component than other similar coating processes.

[0074] Two or more cathodes can be provided, arranged adjacent to each other, opposite each other, and / or directly opposite each other. In this way, multiple conductive components can be coated simultaneously from one side or even from both sides. If coating from both sides, in the case of using directly opposite cathodes, at least one conductive component can be coated simultaneously from both sides, or when the cathodes face each other but are offset relative to each other in the process chamber, one side is coated first, and then the second side is coated using a linear process. Carbon coatings can be deposited using a sputtering process, or alternatively, using an EBPVD process. This allows for the cost-effective fabrication of carbon coatings.

[0075] The carbon coating can be deposited within a time interval ranging from 0.1 minutes to 15 minutes, preferably from 0.5 minutes to 5 minutes. This deposition time interval enables the rapid and efficient fabrication of conductive components.

[0076] One or more cathodes can be arranged on one side of the coating chamber, i.e., a single-sided process can be performed. In this case, the carbon coating can be deposited by, for example, an ARC process, which operates at a current selected between 40 A and 150 A, particularly between 40 A and 90 A, and optionally at a bias selected between -20 V and -400 V, particularly between -80 V and -300 V, or even more preferably between -80 V and -250 V.

[0077] Two or more cathodes can be arranged in the coating chamber and opposite to each other, i.e., a two-sided process can be performed, wherein the carbon coating can be deposited, for example, by operating at least two ARC-type cathodes simultaneously and facing each other, wherein the current is optionally selected between 40 A and 150 A, particularly between 50 A and 100 A, and the bias voltage is selected between -20 V and -400 V, particularly between -40 V and -200 V, and even more preferably between -40 V and -150 V.

[0078] In a preferred embodiment, the carbon coating is deposited over time intervals ranging from 0.1 minutes to 15 minutes. In a more preferred embodiment, the time interval is ranging from 0.5 minutes to 5 minutes. This method enables the mass production of conductive components within a short timeframe. Attached Figure Description

[0079] The invention will now be described in further detail and by way of example only with reference to the accompanying drawings and various examples of conductive components and methods of the invention. In the drawings, it is shown that: Figure 1 This is a schematic cross-sectional view of the conductive component of the present invention; Figure 2 This is a schematic cross-sectional view of another conductive component of the present invention; Figure 3 This is a schematic cross-sectional view of another conductive component of the present invention; Figure 4 This is a schematic cross-sectional view of another conductive component of the present invention; Figure 5 This is a schematic cross-sectional view of another conductive component of the present invention; Figure 6 This is a schematic cross-sectional view of another conductive component of the present invention; Figure 7 This is a high-magnification bright-field TEM image of a cross-sectional view of the conductive component of the present invention; Figure 8a is a high-magnification bright-field TEM image of a cross-sectional view of a reference component (prior art); Figure 8b This is a comparison between the prior art carbon coatings disclosed in EP3778982B1 and the present invention; Figure 9 is an enlarged view of the reference component (prior art) in Figure 8a; Figure 10 This is a schematic cross-sectional view of the carbon coating of the present invention; Figure 11 yes Figure 10 A magnified view of the nanocrystalline graphite component in the image; Figure 12 yes Figure 7High-magnification bright-field TEM image of the cross-sectional view of the carbon coating shown; Figure 13 yes Figure 7 High-magnification bright-field TEM image (bottom image) and its FFT image (top and middle images) of the cross-sectional view of the conductive component shown. Figure 13a It comes from Figure 13 Visualization of the skewness and interlayer spacing of the obtained data; Figure 14 is a high-magnification bright-field TEM image (bottom image) and its FFT image (top and middle image) of the cross-sectional view of the reference component shown in Figure 8a (prior art). Figure 14a is a visualization of the tilt and interlayer spacing of the data obtained from Figure 14 (Prior Art); Figure 15 The reference carbon coating shown in Figure 8a (left) is compared with... Figure 7 A comparison of the carbon coatings shown (right); Figure 16 The reference carbon coating 24 shown in Figure 8a is... Figure 7 The superimposed Raman spectrum of carbon coating 16 shown (x-axis: count (arbitrary units); y-axis: wavelength (nm)). Figure 17 These are high-magnification bright-field TEM images (top images) of the cross-sectional view of the conductive component of the present invention and FFT images (bottom images) obtained from the batch coating process. Figure 18 is a high-magnification bright-field TEM image (top image) and its FFT image (bottom image) of a cross-section of a reference part obtained from a batch coating process (prior art). Figure 19 The online coating device of the present invention; and Figure 20 shows an online coating device based on existing technology. Detailed Implementation

[0080] In the following text, the same reference numerals will be used for parts having the same or equivalent functions. Any statements regarding the orientation of components are made relative to the positions shown in the figures and may naturally vary in actual application.

[0081] Figure 1 A schematic cross-sectional view of the conductive component 10 is shown. The conductive component 10 is formed of two parts: a metal component 12 and a carbon coating 16. The carbon coating 16 is deposited on one side of the metal component 12, specifically covering the entire surface of said side. The carbon coating 16 comprises a single amorphous, at least substantially hydrogen-free DLC layer embedded with a nanocrystalline graphite component (not shown). In this embodiment, the metal component 12 may be or may include titanium.

[0082] Figure 2 A schematic cross-sectional view of another conductive component 10' is shown. The conductive component 10 is formed of three parts: a metal component 12, an adhesive layer 14, and a carbon coating 16. The metal component 12, the adhesive layer 14, and the carbon coating 16 are arranged in a stacked manner, with the adhesive layer 14 located in the middle. Figure 1 Similarly, only one side of the metal component is coated. Adhesive layer 14 preferably covers the entire surface of said side. And carbon coating 16 preferably covers the entire surface of the side of adhesive layer 14 opposite to the metal component 12. Carbon coating 16 comprises a single amorphous, at least substantially hydrogen-free DLC layer embedded with a nanocrystalline graphite component (not shown). In this embodiment, the metal component 12 may be, or may include, titanium and / or stainless steel.

[0083] Figure 3 A schematic cross-sectional view of another conductive component 10a is shown. This component 10a is related to... Figure 1 The components 10 are nearly identical, except that the carbon coating 16 of component 10a comprises two different types of amorphous, at least substantially hydrogen-free DLC layers 18a and 18b. For example, DLC layer 18a is an ac DLC layer, and DLC layer 18b is a ta-c DLC layer. Notably, at least one of the DLC layers 18a and 18b is embedded with a nanocrystalline graphite component (not shown). Preferably, both 18a and 18b are embedded with a nanocrystalline graphite component (not shown). It is also possible that both DLC layers 18a and 18b are either ac DLC layers or ta-c DLC layers, however, each of which contains a different amount of nanocrystalline graphite component (not shown).

[0084] Figure 3 The carbon coating 16 can also be formed from three (3) or more amorphous, at least substantially hydrogen-free DLC layers (18a, 18b, 18c, etc.; not shown). In this case, at least one of the DLC layers is embedded with a nanocrystalline graphite component (not shown). Preferably, each DLC layer is embedded with a nanocrystalline graphite component (not shown).

[0085] Figure 4 A schematic cross-sectional view of another conductive component 10b is shown. This component 10b is related to... Figure 2The components 10' are nearly similar, except that the carbon coating 16 of component 10a comprises two different types of amorphous, at least substantially hydrogen-free DLC layers 18a and 18b. For example, DLC layer 18a is an ac DLC layer, and DLC layer 18b is a ta-c DLC layer. Notably, at least one of the DLC layers 18a and 18b is embedded with a nanocrystalline graphite component (not shown). Preferably, both 18a and 18b are embedded with a nanocrystalline graphite component (not shown). It is also possible that both DLC layers 18a and 18b are either ac DLC layers or ta-c DLC layers, however, each of which contains a certain amount of nanocrystalline graphite component (not shown).

[0086] Figure 4 The carbon coating 16 can also be formed from three (3) or more amorphous, at least substantially hydrogen-free DLC layers (18a, 18b, 18c, etc.; not shown). In this case, at least one of the DLC layers is embedded with a nanocrystalline graphite component (not shown). Preferably, each DLC layer is embedded with a nanocrystalline graphite component (not shown).

[0087] Figure 5 A schematic cross-sectional view of another conductive component 10'' is shown. The arrangement and composition of component 10'' are similar to... Figure 1 The components 10 shown are nearly identical, except that component 10'' is coated on two opposite sides (i.e., surfaces) of the metal component. Therefore, component 10'' can be a symmetrical conductive component. The carbon coatings 16, 16' in component 10'' have the same thickness. However, depending on the application of component 10'', the carbon coatings 16, 16' in this component 10'' can be different. For example, the two coatings 16, 16' can differ in their thickness, hardness, and / or composition (not shown). Alternatively, the two coatings 16, 16' can have the same thickness, hardness, and / or composition. This component 10'' can be used in fuel cell stacks, specifically as a bipolar plate (not shown).

[0088] It is worth noting that, Figure 5 The conductive component 10'' shown may comprise a carbon coating 16 consisting of two different types of amorphous, at least substantially hydrogen-free DLC layers 18a, 18b, similar to Figure 3 Component 10a. Therefore, Figure 3 At least some parts of the description may apply to part 10''.

[0089] Figure 6 A schematic cross-sectional view of another conductive component 10''' is shown. The arrangement and composition of component 10''' are similar to... Figure 2The components 10' shown are almost identical, except that component 10''' is coated on two sides of the metal component facing opposite directions. Therefore, component 10''' can be a symmetrical conductive component. Regarding... Figure 3 The description can be applied to part 10'''. For example... Figure 4 As shown, the adhesive layers 14 and 14' in component 10''' have the same thickness. However, depending on the application of component 10'', the adhesive layers 14 and 14' in this component 10''' can be different. For example, the two adhesive layers 14 and 14' can differ in their thickness and / or composition. The two adhesive layers 14 and 14' can alternatively have the same or different thickness and / or composition. This component 10''' can be used in a fuel cell stack, specifically as a bipolar plate (not shown).

[0090] It is worth noting that, Figure 6 The conductive component 10''' shown may comprise a carbon coating 16 consisting of two different types of amorphous, at least substantially hydrogen-free DLC layers 18a, 18b, similar to Figure 4 Component 10b. Therefore, Figure 4 At least some parts of the description may apply to part 10'''.

[0091] Figure 7 A high-magnification bright-field TEM image showing a cross-sectional view of the conductive component 10''' is provided. The component 10''' is formed of a metal component 12 (not shown), two adhesive layers 14 (shown) and 14' (not shown) facing opposite directions, and two carbon coatings 16 (shown) and 16' (not shown) facing opposite directions, as shown. Figure 6 As schematically shown, the carbon coating 16 exhibits a uniform, homogeneous structure (i.e., composition) in the nanometer range. This indicates that the nanocrystalline graphite component 20 is embedded in the amorphous, at least substantially hydrogen-free, DLC layer 18 throughout the carbon coating 16.

[0092] Discovered Figure 7 The conductive components in it have good electrical and mechanical properties, as well as low contact resistance, i.e., 0.002 Ω·cm² or lower.

[0093] It is worth noting that in production Figure 7 When the conductive component 10''' is shown, the temperature distribution of the metal component with the adhesion layer is uniform during the carbon coating step on both sides.

[0094] for Figure 7 The conductive component 10''' shown was manufactured using an in-line coating apparatus, in which the arc cathodes face each other (i.e., are arranged parallel to each other), for example, as shown in the figure. Figure 19As shown. The metal component 12 is etched using an argon plasma etching process performed over a 3-minute time period, with a bipolar bias ranging from -150V to -350V. The etching process is performed by subsequently etching the first and second sides of the metal component 12. When the etching process is performed simultaneously on both sides of the metal component 12 (not shown), no mass loss of the conductive component 10''' is observed. Adhesion layers 14, 14' are then deposited using a sputtering process at a bias ranging from -20V to -350V. The thickness of adhesion layer 14 is approximately 100 nm. The deposition of adhesion layers 14, 14' is performed simultaneously on the first and second sides of the metal component 12. When the adhesion layer process is subsequently performed on both sides of the metal component 12 (not shown), no mass loss of the conductive component 10''' is observed. Carbon coatings 16 and 16' are deposited using an arc PVD process at a bias voltage of -20 V to -400 V, wherein both sides of the metal parts (14 and 14') with the adhesion layer undergo the carbon coating step simultaneously.

[0095] Figure 8a shows a high-magnification bright-field TEM image of a cross-sectional view of the reference component 22. The reference component 22 is formed of a metal component 12 (not shown), two adhesive layers 14 (shown) and 14' (not shown) facing opposite directions, and two carbon coatings 24 (shown) and 24' (not shown) facing opposite directions, as... Figure 6 The diagram is schematically shown (however, it includes a reference carbon coating). With Figure 7 Compared to the carbon coating 16 in the reference carbon coating, the reference carbon coating 24 exhibits a non-uniform, heterogeneous structure (i.e., composition) in the nanometer range. Instead, the reference carbon coating 24 comprises two separate layers: an amorphous carbon layer 26 and a graphite crystal layer 28. The amorphous carbon layer 26 is significantly darker than the graphite crystal layer 28 and can therefore be distinguished by the boundary 30; see also the enlarged view of Figure 8a in Figure 9. This stacked (i.e., non-embedded) arrangement of the amorphous carbon layer 26 and the graphite crystal layer 28 is also confirmed by Fast Fourier Transform (FFT) imaging, as further described below.

[0096] The reference component in Figure 8a has been found to be... Figure 7 Compared to the coating shown, this coating exhibits poorer electrical and mechanical properties, as well as a high contact resistance value; specifically, the contact resistance value of the reference component in Figure 8a is >> 0.005 Ω·cm². It is worth noting that during the production of the reference component 22 shown in Figures 8a and 9, the temperature distribution of the metal component with the adhesion layer was uneven during the carbon coating step.

[0097] Figure 8bA comparison is shown between a prior art carbon coating (top image) disclosed in EP3778982B1 (which is similar to the carbon coating shown in FIG8a) and a carbon coating manufactured according to the present invention (bottom image) as a corresponding high-magnification bright-field TEM image of a cross-sectional view of carbon coating 16.

[0098] It can be clearly seen that the top image shows a disordered structure, while the cross-sectional view of the carbon coating 16 shown in the bottom image reveals that the carbon coating 16 comprises an amorphous, at least substantially hydrogen-free DLC layer 18, in which nanocrystalline graphite components 20 are embedded (indicated by parallel lines). Several such portions are shown, indicating that the carbon coating 16 has an ordered structure. In this regard, reference is also made to… Figures 10 to 12 This ordered structure results in improved adhesion of the carbon coating 16 to the conductive component 10 and improved layer quality.

[0099] This improved layer quality results from differences in coating parameters selected through comparison with those disclosed in EP3778982B1 and the present invention. These differences lie in the applied current, bias voltage, and substrate temperature.

[0100] Figure 10 A schematic cross-sectional view of the carbon coating 16 is shown. The carbon coating 16 comprises an amorphous, at least substantially hydrogen-free DLC layer 18, in which nanocrystalline graphite component 20 is embedded. A portion of the total nanocrystalline graphite component 20 is aligned perpendicular to axis A, as shown for component 20a. Additionally (shown) or alternatively (not shown), a portion of the total nanocrystalline graphite component 20 is tilted relative to axis P perpendicular to axis A, as shown for component 20b with a tilt of +15 degrees and component 20c with a tilt of -15 degrees. Of course, the carbon coating may include nanocrystalline graphite components (not shown) with other tilt angles selected in the range of ±30 degrees or less. Figure 10 Each nanocrystalline component shown is formed by five (5) stacked layers.

[0101] Figure 11 It shows Figure 10 An enlarged view of the tilted nanocrystalline graphite component 20b. The tilt angle 32 of each nanocrystalline graphite component can be determined relative to the axis P perpendicular to axis A, as shown in the figure. Of course, the tilt angle of nanocrystalline graphite component 20a is 0 degrees because it is perpendicular to axis A. Furthermore, Figure 11 The interlayer spacing 34 between two stacked layers of nanocrystalline graphite component 20b is shown. The interlayer spacing (i.e., the spacing) 34 is preferably 0.3 nm, which corresponds to the lattice spacing of the graphite (0002) plane.

[0102] Figure 12 It shows Figure 7A high-magnification bright-field TEM image of a cross-sectional view of the carbon coating 16 is shown. The TEM image reveals multiple island-like components in the form of stacked lines, i.e., a series of locally dashed lines. Each of these components is assigned to the nanocrystalline graphite component 20. For better visualization, Figure 12 Three of these components, 20a, 20b, and 20c, are highlighted in the figure. It can be seen that components 20a, 20b, and 20c are formed by four (4) stacked layers. The nanocrystalline graphite component 20a is aligned perpendicular to axis A. The nanocrystalline graphite components 20b and 20c are tilted relative to axis P, which is perpendicular to axis A. As shown in the figure, the tilt is ±15 degrees.

[0103] Figure 13 It shows Figure 7 The image shows a high-magnification bright-field TEM image (bottom image) and its FFT images (top and middle images) of a cross-sectional view of the conductive component. (See above regarding...) Figure 7 As previously outlined, a carbon coating process is used to coat conductive components on two opposite sides. The left image shows a TEM image and two FFT images of the carbon coating 16 on the first side of the metal component 12. The right image shows a TEM image and two FFT images of the carbon coating 16' on the second side of the metal component 12. The Fast Fourier Transform (FFT) images on both sides show that the upper (large dashed rectangle) and lower (small solid rectangle) portions of the carbon coatings 16, 16' comprise an amorphous, at least substantially hydrogen-free DLC layer embedded with nanocrystalline graphite components. Therefore, the embedding is displayed uniformly throughout the DLC layer. Furthermore, the enhanced signal to the left and right of the center point in the FFT images indicates the periodicity of the C lattice planes perpendicular to the surface (spacing of 0.32 ± 0.02 nm). The arcuate appearance of the FFT spots is related to variations in the orientation of the C lattice planes.

[0104] Figure 13a Showing from Figure 13 The obtained data includes visualizations of the tilt and interlayer spacing. The entire amorphous, at least substantially hydrogen-free DLC layer (i.e., the top portion / layer and the bottom portion / layer) is embedded with highly ordered nanocrystalline graphite components.

[0105] Figure 14 shows a high-magnification bright-field TEM image (bottom image) and its FFT images (top and middle images) of a cross-sectional view of the reference component shown in Figure 8a. As outlined above with respect to Figure 8a, carbon coating is applied to the conductive component on two opposite sides using an in-line coating process. The left image shows a TEM image and two FFT images of the reference carbon coating 24 on the first side of the metal component 12. The right image shows a TEM image and two FFT images of the carbon coating 24' on the second side of the metal component 12. The Fast Fourier Transform (FFT) images on both sides show that the upper (dashed rectangle) and lower (solid rectangle) portions of the carbon coatings 24, 24' have different compositions. Figure 13 In contrast, the FFT image of the upper part of layer C shows concentrated spots that are not arc-shaped, indicating that the orientation of the C lattice plane remains unchanged. The spots in the lower part of layer C are less prominent in the FFT image, indicating the amorphous nature of this layer. In summary, the obtained FFT images show that reference component 22 consists of a lower amorphous carbon layer 26 and an upper graphite crystal layer 28, i.e., a stacked arrangement of layers 26 and 28. Therefore, the graphite crystals in layer 28 are not embedded in the amorphous carbon layer 26.

[0106] Figure 14a shows a visualization of the tilt and interlayer spacing from the data obtained in Figure 14. Only the upper part (i.e., layer) of the reference carbon layer shows the presence of graphite crystals. The lower part (i.e., layer) of the reference carbon layer shows only the presence of amorphous carbon layers.

[0107] Figure 15 A comparison is shown between reference carbon coating 24 (left) and the carbon coating 16 of the present invention (right). TEM images show magnified views of the amorphous carbon layer 26 of the reference component 22 shown in FIG. 8a, and... Figure 7 An enlarged view of the conductive component 10 shown and described. The left image shows the completely amorphous structure in the amorphous carbon layer 26 of the reference component 22. In contrast, the right image shows a series of nanocrystalline graphite components 20 having an interlayer spacing 34 and embedded in an amorphous, at least substantially hydrogen-free DLC layer 18. Some of the nanocrystalline graphite components 20 are depicted for visual purposes. Compared to the amorphous carbon layer 24, the amorphous, at least substantially hydrogen-free DLC layer 18 of the conductive component 10 contains nanocrystalline graphite components 20 throughout the DLC layer. As shown, the aspect ratios of the components 20 vary. In one example, the aspect ratio of the components 20 is 1:1.1. At the top of the right image, two stacked layers (not shown) of the nanocrystalline components are depicted. The interlayer spacing between the two stacked layers is 0.32 nm.

[0108] Figure 16 The reference carbon coating 24 shown in Figure 8a is illustrated. Figure 7 The superimposed Raman spectrum of carbon coating 16 is shown. Figure 16In the spectrum of carbon coating 16, the D peak (approximately 1400 cm⁻¹) is observed. - ¹The deconvolution Gaussian peak) and the G peak (approximately 1590 cm⁻¹) - The ID / IG ratio (i.e., 1.9) of the deconvolution Gaussian peak ¹ is higher than that of the reference carbon coating 24 (i.e., 1.8). The higher ID / IG ratio is associated with a higher sp... 2 The content is related, thus indicating the nanocrystalline graphite component. Figure 16 The ID / IG ratios in the data are respectively compared with... Figure 7 It matches the TEM image shown in Figure 8a.

[0109] Figure 17 A high-magnification bright-field TEM image (top image) showing a cross-sectional view of the conductive component of the present invention and its FFT image (bottom image) obtained from a batch coating process are shown. Figure 7 , Figure 12 , Figure 13 , Figure 13a and Figure 15 Compared to the conductive components on the right, Figure 17 The conductive component analyzed (sample B) was produced using a batch coating process. The top image shows that the carbon coating of sample B consists of a first (bottom (interface)) layer of amorphous DLC layers embedded with highly ordered nanocrystalline graphite components, which are at least substantially hydrogen-free, and a second (top (surface)) layer of amorphous DLC layers embedded with highly ordered nanocrystalline graphite components, which are at least substantially hydrogen-free.

[0110] for Figure 17 The conductive components shown were manufactured using a batch coating apparatus. The metal components were etched using an argon plasma etching process performed over a 3-minute time period, with a bipolar bias ranging from -0 to -350 V. The etching process was performed by subsequently etching the first and second sides of the metal components. An adhesion layer was then deposited using a sputtering process at a bias ranging from -20 V to -350 V. The thickness of the adhesion layer was approximately 100 to 120 nm. The adhesion layer was subsequently deposited on both the first and second sides of the metal components. A carbon coating was deposited using an arc PVD process at a bias ranging from -20 V to -400 V, with each side of the metal component having the adhesion layer subsequently undergoing carbon coating. No loss of conductive component quality was observed when etching, adhesion layer deposition, or carbon coating was performed simultaneously on both sides of the metal component 12.

[0111] Discovered Figure 17 The conductive components in it have good electrical and mechanical properties, as well as low contact resistance, i.e., 0.001 Ω·cm² or lower.

[0112] Figure 18 shows a high-magnification bright-field TEM image (top image) and its FFT image (bottom image) of a cross-sectional view of a reference component obtained from a batch coating process (prior art). (Compare with Figures 8, 9, 14, 14a, and...) Figure 15 Compared to the reference component in the left image, the reference component (sample C) analyzed in Figure 18 was produced using a batch coating process. The FFT image only shows the amorphous coating without orientation.

[0113] The D peak (approximately 1400 cm⁻¹) in the Raman spectrum (not shown) of the sample with the reference carbon coating shown in Figure 18. - ¹The deconvolution Gaussian peak) and the G peak (approximately 1590 cm⁻¹) - The ID / IG ratio of the deconvolution Gaussian peak (¹) is 1.2, i.e., ID / IG = 1.2. Such a low ID / IG ratio indicates that there is no nanocrystalline graphite component in the entire carbon layer.

[0114] The reference component in Figure 18 has been found to have poor electrical and mechanical properties, as well as a high contact resistance value, namely >>0.005 Ω·cm².

[0115] Figure 19 An online coating apparatus 36 of the present invention is shown. The process is carried out in an inert gas atmosphere (e.g., an argon atmosphere). Each of chambers 38, 40, 42, and 44 is a vacuum chamber. After a metal component 12 (not shown) is inserted into the loading chamber 38 of the apparatus 36, the metal component 12 undergoes an etching step in chamber 40. Etching is shown to occur on two opposite sides of the metal component 12. Subsequently, the two etched sides of the metal component have an adhesive layer in the next chamber 42. Deposition of the adhesive layers 14, 14' can be performed simultaneously or subsequently on both sides. The metal component 12, including the adhesive layers 14, 14', is then carbon coated in a carbon coating chamber 44. During the carbon coating deposition step, chamber 44 preferably has a temperature in the range of 23°C to 450°C. The plate itself can reach 100°C to 450°C, preferably 250°C to 450°C, during carbon deposition, depending on the deposition parameters used. As shown in the figure, the carbon coating sources (here, the arc cathode) are arranged parallel to each other, i.e., without tilting. This allows carbon coating to be performed simultaneously on both sides of the metal component, thereby ensuring a stable temperature gradient during carbon coating. This device provides the conductive component of the present invention.

[0116] Figure 20 illustrates an online coating apparatus 46 according to the prior art. Apparatus 46 and... Figure 19The devices described are almost identical, except that the carbon-coated chamber has two arc cathodes offset from each other (i.e., not parallel to each other). The arc cathodes then carbon-coat both sides of the metal component 12. This method cannot provide a stable temperature gradient during carbon coating. Therefore, the resulting carbon-coated component exhibits poor electrical and mechanical properties, as well as high contact resistance.

[0117] List of reference numerals in the attached diagram: Axis A P axis P 10, 10', 10'', 10''' conductive components 10a, 10a' conductive components 12 metal parts 14, 14' Adhesion Layer 16' carbon coating 18, 18a, 18b Amorphous, at least substantially hydrogen-free DLC layers 20, 20a, 20b, 20c nanocrystalline graphite components 22 Reference Components 24, 24' Reference Carbon Coating 26 amorphous carbon layers 28 graphite crystal layers 30 boundary 32 degrees of inclination 34-story spacing 36 Online Coating Equipment 38 Loading Chamber (Vacuum Chamber) 40 Etching Chambers (Vacuum Chambers) 42. Chambers (vacuum chambers) used for depositing adhesion layers. 44 Carbon-coated chamber (vacuum chamber) 46. ​​Online coating equipment (existing technology) 48 carbon coated chamber (vacuum chamber; prior art).

Claims

1. A conductive component, such as a bipolar plate, a half-plate, an electrode, and a gasket, the conductive component comprising: Metal parts; The uncoated metal component has a first side and a second side, which face different directions, such as opposite directions. A corresponding adhesive layer, optionally formed on at least one of the first and second sides of the metal component; and The corresponding carbon coating, if the corresponding adhesive layer is provided, is formed on at least one of the first side and the second side of the corresponding adhesive layer, or the corresponding carbon coating is formed on at least one of the first side and / or the second side of the metal component; The corresponding carbon coating comprises an amorphous, at least substantially hydrogen-free DLC layer and at least one nanocrystalline graphite component embedded in the amorphous, at least substantially hydrogen-free DLC layer. The at least one nanocrystalline graphite component comprises two or more stacked layers; and The at least one nanocrystalline graphite component is aligned perpendicular to and / or at least substantially perpendicular to axis A defined by the interface between the carbon coating and the metal component, or if the adhesive layer is provided, the at least one nanocrystalline graphite component is aligned perpendicular to and / or at least substantially perpendicular to axis A defined by the interface between the carbon coating and the adhesive layer.

2. The conductive component according to claim 1, wherein the metal component has a first side and a second side, the first side and the second side facing different directions, preferably opposite directions; the adhesive layer is optionally formed on at least one of the first side and / or the second side of the metal component; The carbon coating is formed on the first and second sides of the metal component, and the first and / or second sides of the metal component may optionally have an adhesion layer.

3. The conductive component according to claim 2, wherein the carbon coating on the first side of the metal component and the carbon coating on the second side of the metal component are similar to or different from each other, and the first side and / or the second side of the metal component optionally have an adhesion layer.

4. The conductive component according to any one of claims 1 to 3, wherein the amorphous, at least substantially hydrogen-free DLC layer comprises one or more ta-C layers and / or one or more aC layers.

5. The conductive component according to any one of claims 1 to 4, wherein the sp of the amorphous, at least substantially hydrogen-free DLC layer is... 2 with sp 3 The content of sp ranges from 30% to 80%. 2 Up to 70% to 20% of sp 3 Within this range, particularly where the amorphous, at least substantially hydrogen-free DLC layer is 100%, the sp 2 content higher than 40% of sp 2 And especially higher than 60% of sp 2 .

6. The conductive component according to any one of claims 1 to 5, wherein the amorphous, at least substantially hydrogen-free DLC layer is 100 at%, and the amorphous, at least substantially hydrogen-free DLC layer is a DLC layer containing less than 1 at% hydrogen.

7. The conductive component according to any one of claims 1 to 6, wherein the at least one nanocrystalline graphite component comprises two (2), three (3), four (4), five (5), ten (10), fifteen (15) or more stacked layers, preferably three (3) or more stacked layers.

8. The conductive component according to any one of claims 1 to 7, wherein the at least one nanocrystalline graphite component has an aspect ratio of 1:1 to 1:20, preferably 1:5, 1:1.1 or 1:

1.

9. The conductive component according to any one of claims 1 to 8, wherein the stacked layer of the nanocrystalline graphite component has a layer spacing of 0.1 nm to 2 nm, preferably 0.2 nm to 0.6 nm, and more preferably 0.3 nm.

10. The conductive component according to any one of claims 1 to 9, wherein the nanocrystalline graphite component aligned at least substantially perpendicular to the axis A is a nanocrystalline graphite component tilted at ±30 degrees or less, preferably ±20 degrees or less, ±15 degrees or less, ±10 degrees or less, or ±5 degrees or less relative to the axis P perpendicular to the axis A.

11. The conductive component according to any one of claims 1 to 10, wherein, based on the total amount (100%) of the carbon coating, the ratio of the amount of the amorphous, at least substantially hydrogen-free DLC layer to the amount of the at least one nanocrystalline graphite component is in the range of 20% to 90%, preferably in the range of 30% to 70% or 40% to 80%.

12. The conductive component according to any one of claims 1 to 11, wherein the carbon coating has a thickness of 5 to 300 nm, preferably 15 to 150 nm, and more preferably 25 to 100 nm.

13. The conductive component according to any one of claims 1 to 12, further comprising the adhesive layer, wherein the adhesive layer comprises at least one material selected from the group consisting of: titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, nickel, cobalt, magnesium, gadolinium, nitrogen, carbon, boron, aluminum, and combinations thereof, and preferably includes titanium.

14. The conductive component according to any one of claims 1 to 13, wherein the amorphous, at least substantially hydrogen-free DLC layer is 100 at%, and the amorphous, at least substantially hydrogen-free DLC layer has an argon content of less than 5 at%, preferably less than 2 at%, and more preferably less than 1 at%.

15. The conductive component according to any one of claims 1 to 14, wherein the amorphous, at least substantially hydrogen-free DLC layer is 100 at, and the amorphous, at least substantially hydrogen-free DLC layer has an iron content of less than 5 at%, preferably less than 1 at.

16. The conductive component according to any one of claims 1 to 15, wherein the conductive component has a contact resistance (CR) of 0.01 Ω·cm² or less, preferably 0.003 Ω·cm² or less, measured at a contact pressure of 1 MPa.

17. A method for coating at least one conductive component, particularly at least one conductive component according to at least one of claims 1 to 16, said conductive component being such as a bipolar plate, half-plate, electrode, gasket, etc., said method comprising the steps of: - Provide an uncoated metal component; the uncoated metal component has a first side and a second side, the first side and the second side facing different directions, for example, opposite directions; - Etch at least one of the first side and the second side of the uncoated metal component; - Optionally, an adhesion layer may be deposited on at least one of the first side and / or the second side of the etched uncoated metal part by means of one of physical vapor deposition, arc physical vapor deposition, arc ion plating, sputtering, EBPVD or Hipims process. as well as -If the adhesive layer is provided, a carbon coating is deposited on the adhesive layer on at least one of the first side and the second side, or a carbon coating is deposited directly on at least one of the etched first side and / or second side of the uncoated metal part. The carbon coating is deposited using at least one of physical vapor deposition (PVD) processes, such as arc PVD, sputtering, arc ion plating, EBPVD (electron beam physical vapor deposition), and / or Hipims processes, at a bias voltage of -20 V to -400 V with a layer thickness selected from 5 nm to 300 nm.

18. The method of claim 17, wherein: The uncoated metal component has a first side and a second side, the first side and the second side facing different directions, for example, opposite directions; The first and second sides of the uncoated metal component are etched; An adhesion layer may optionally be deposited on at least one of the first and second sides of the etched, uncoated metal part; Furthermore, if an adhesive layer is provided, the first and second sides having the adhesive layer are coated with a carbon coating and / or the etched first and second sides are coated with a carbon coating.

19. The method of claim 18, wherein if an adhesive layer is provided, the carbon coating is simultaneously deposited on the first side and the second side having the adhesive layer, and / or the carbon coating is simultaneously deposited on the etched first side and the second side.

20. The method according to any one of claims 17 to 19, wherein during the carbon coating step, the metal component is subjected to continuous heating, and if the adhesive layer is provided, the metal component and the adhesive layer are subjected to continuous heating.

21. The method according to any one of claims 17 to 20, wherein the etching step comprises a plasma etching process, preferably an argon plasma etching process, performed over a time period of 0.1 minutes to 60 minutes, particularly 0.5 minutes to 5 minutes, wherein the bias voltage is in the range of -50 V to -1200 V, preferably in the range of -150 V to -350 V.

22. The method according to any one of claims 17 to 20, wherein the etching step comprises a metal ion etching process performed in a time period ranging from 0.1 minutes to 60 minutes, particularly from 0.5 minutes to 5 minutes, wherein the bias voltage is in the range of -50V to -1200V, preferably in the range of -600V to -1200V.

23. The method of claim 21 or 22, wherein the bias voltage during the etching step comprises DC, unipolar, and / or bipolar.

24. The method according to any one of claims 17 to 23, further comprising: The step of depositing the adhesion layer, wherein the step includes depositing an adhesion layer with a thickness in the range of 25 nm to 500 nm under a bias voltage in the range of -0 V to -350 V.

25. The method according to any one of claims 17 to 24, further comprising: The step of depositing the adhesion layer, wherein the adhesion layer is preferably deposited using an arc PVD process at a bias voltage in the range of -20 V to -400 V.

26. The method according to any one of claims 17 to 25, further comprising: The step of depositing the adhesion layer, wherein the adhesion layer is preferably deposited using a sputtering process and / or a HIPIMS process at a bias voltage in the range of -20 V to -350 V.

27. The method according to any one of claims 17 to 26, further comprising: The step of depositing the adhesion layer, wherein the adhesion layer comprises at least one of Ti, Cr, V, Ta, Ni, Co, Nb, Mg, B, Gd, Zr, TiN, CrN, NbN, ZrN, and combinations thereof.

28. The method according to any one of claims 17 to 27, wherein the carbon coating comprises an amorphous, at least substantially hydrogen-free DLC layer and at least one nanocrystalline graphite component embedded in the amorphous, at least substantially hydrogen-free DLC layer.

29. The method of claim 28, wherein the amorphous, at least substantially hydrogen-free DLC layer comprises a top layer in which dopants are present, or comprises dopants throughout the amorphous, at least substantially hydrogen-free DLC layer.

30. The method of claim 29, wherein the dopant is selected from the group consisting of: titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, nitrogen, boron, silicon, and combinations thereof.

31. The method of claim 29 or claim 30, wherein the amorphous, at least substantially hydrogen-free DLC layer is 100 at% or the top layer of the amorphous, at least substantially hydrogen-free DLC layer including the dopant is 100 at%, and the percentage of the dopant is 0.2 at% to 10 at%, particularly 0.5 at% to 6 at% or 2 at% to 4 at%.

32. The method according to any one of claims 17 to 31, wherein the method is carried out in a vacuum chamber such as an online coating system or a batch coating system, and during the step of depositing a carbon coating, the temperature of the metal component is adjusted to a temperature in the range of 100°C to 450°C, particularly in the range of 250°C to 450°C.

33. The method according to any one of claims 17 to 32, wherein the carbon coating is deposited with a layer thickness in the range of 5 nm to 300 nm, preferably 15 nm to 150 nm, and more preferably 25 nm to 100 nm.

34. The method according to any one of claims 17 to 33, wherein the carbon coating is deposited under a bias voltage in the range of -20 V to -400 V, particularly between -40 V and -300 V, and even more preferably between -40 V and -250 V.

35. The method according to any one of claims 17 to 34, wherein the carbon coating is deposited using the arc physical vapor deposition process or the arc ion plating process, and wherein the arc cathode current is preferably in the range of 40 A to 150 A, more preferably in the range of 40 A to 90 A.

36. The method according to any one of claims 17 to 35, wherein the carbon coating is deposited using the HIPIMS process, and wherein the target density is 70 Watt / cm² or higher.

37. The method according to any one of claims 17 to 36, wherein one or more cathodes are provided for coating the at least one conductive component, wherein the cathodes are arranged on one or more sides of the coating chamber.

38. The method of claim 37, wherein one of the arc deposition process and the HIPIMS process is used to coat the at least one conductive component.

39. The method of claim 37 or claim 38, wherein two or more cathodes are provided, the two or more cathodes being arranged adjacent to each other, opposite to each other, and / or directly opposite each other.

40. The method according to any one of claims 17 to 39, wherein the carbon coating is deposited using a sputtering process.

41. The method according to any one of claims 17 to 40, wherein the carbon coating is deposited using an EBPVD process.

42. The method according to any one of claims 17 to 41, wherein the carbon coating is deposited within a time interval ranging from 0.1 minutes to 15 minutes, preferably from 0.5 minutes to 5 minutes.

43. The method according to any one of claims 17 to 42, wherein the one or more cathodes are arranged on one side of the coating chamber, wherein the carbon coating is deposited by, for example, an ARC process, the ARC process being operated at a current selected between 40 A and 150 A, particularly between 40 A and 90 A, and at a bias selected between -20 V and -400 V, particularly between -80 V and -300 V, and even more preferably between -80 V and -250 V.

44. The method according to any one of claims 17 to 42, wherein two or more cathodes are provided in a coating chamber and said two or more cathodes are arranged opposite to each other, wherein said carbon coating is deposited with said two or more cathodes using a current selected between 40 A and 150 A, particularly between 50 A and 100 A, and a bias selected between -20 V and -400 V, particularly between -40 V and -200 V, and even more preferably between -40 V and -150 V.

45. An apparatus for coating at least one conductive component, particularly at least one conductive component according to at least one of claims 1 to 16, said at least one conductive component being such as one or more bipolar plates, one or more half-plates, one or more electrodes, one or more gaskets, etc., said apparatus being configured to perform the method according to any one of claims 17 to 44, said apparatus being an in-line coating system comprising: - Multiple vacuum chambers, wherein the multiple vacuum chambers are arranged in series in sequence; - One or more cathodes, said one or more cathodes being arranged in at least some of the plurality of vacuum chambers; as well as - One or more fixtures, each of which is configured to receive a plurality of the uncoated metal parts, wherein a first outer surface and a second outer surface to be coated each face a cathode, the cathode being a cathode for at least one of physical vapor deposition (PVD) processes, such as arc PVD, sputtering processes, arc ion plating processes, EBPVD (electron beam physical vapor deposition) processes and / or HIPIMS processes. The one or more fixtures are arranged to move linearly within and from the respective vacuum chamber, wherein each vacuum chamber is configured to perform a process, preferably a static process, wherein the process is selected from a group of members including: heating, evacuation, etching, cooling, deposition of an adhesion layer, carbon coating, removal, and / or combinations thereof. The cathodes in the vacuum chamber configured to perform the carbon coating process are arranged substantially parallel to each other.

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