Method for producing a coated metal substrate plate, substrate plate, electrochemical cell, and coating installation

Abstract

The invention relates to a method for producing a coated metal substrate plate (10), wherein a metal substrate plate (1) is coated with an adhesion promoter layer (2) in a first surface region by means of an arc vapour deposition (Arc-PVD) method, at least one single layer of a tetrahedral amorphous carbon layer (3) of the ta-C:H type having at least 3 wt.% hydrogen is formed with a first layer thickness in the range from 10 to 500 nm on the adhesion promoter layer (2) by means of the arc vapour deposition (Arc-PVD) method, wherein a temperature of the metal substrate plate (1), of the adhesion promoter layer (2) and of the tetrahedral amorphous carbon layer (3) is maintained in the range from 100 to 180°C during coating. The invention also relates to a coated metal substrate plate (10) produced thereby and to an electrochemical cell (20) comprising at least one such metal substrate plate, and to a coating installation (200) for carrying out the method.

Description

[0001] Method for producing a coated metallic substrate plate, substrate plate, electrochemical cell and coating system

[0002] The invention relates to a method for producing a coated metallic substrate plate, in which a metallic substrate plate is coated with an adhesion promoter layer in a first surface region using an arc evaporation process (arc PVD). At least one individual layer of a tetrahedral amorphous carbon layer is formed on the adhesion promoter layer using the arc evaporation process (arc PVD). The invention further relates to a coated metallic substrate plate and an electrochemical cell. Furthermore, the invention relates to a coating system for carrying out the method.

[0003] Carbon-based coatings for applications in electrochemical cells are state of the art, but in practice they are usually only electrochemically stable up to 1.0 volts (over 6 hours).

[0004] WO 2022 / 013317 A1 describes a coated bipolar plate for use in a hydrogen-powered polymer electrolyte fuel cell and a method for its production. The stainless steel bipolar plate has a metallic seed layer, an intermediate layer of metal nitride based on the metal of the seed layer, and a cover layer of amorphous carbon of type aC with a density greater than 2.0 g / cm 3 and a molar hydrogen content of maximum 5%.

[0005] WO 2021 / 028399 A1 describes a method for coating metallic components of a fuel cell stack. The uncoated metallic component, such as a bipolar plate, is etched, an optional adhesion promoter layer is applied, and finally, a carbon layer is applied, for example, using an arc evaporation process. A hydrogen-free DLC layer, in particular of the ta-C or aC type, is applied as the carbon layer, with a layer thickness in the range of 5 to 500 nm at a bias voltage of -0 to -200 V. For this purpose, a space in a vacuum chamber is regulated to a temperature in the range of 120 to 400°C during the coating application to form the carbon layer.

[0006] The object of the invention is to provide a method for producing a coated metallic substrate plate with a tetrahedral amorphous carbon layer, which exhibits electrochemical stability up to 1.4 volts (up to 6 hours). Furthermore, the object of the invention is to provide a coated metallic substrate plate produced in accordance with this method and an electrochemical cell formed therewith. Furthermore, the object of the invention is to provide a coating system for carrying out the method according to the invention.

[0007] The object is achieved for the method for producing a coated metallic substrate plate by coating a metallic substrate plate with an adhesion promoter layer in a first surface region by means of an arc evaporation process (Arc-PVD), on the adhesion promoter layer at least one individual layer of a tetrahedral amorphous carbon layer of the ta-C:H type comprising at least 3 wt.% hydrogen in a first layer thickness in the range from 10 to 500 nm is formed by means of the arc evaporation process (Arc-PVD), and wherein a temperature of the metallic substrate plate, the adhesion promoter layer and the tetrahedral amorphous carbon layer is maintained in the range from 100 to 180°C during the coating.

[0008] Such a tetrahedral amorphous carbon layer of the type ta-C:H predominantly, i.e. more than 50%, has a bond type of the type sp 3For this, see the VDI guideline VDI 2840 from June 2012, Chapter 4 on Fundamentals, pages 9 to 11.

[0009] Due to the very high energy input during the production of tetrahedral amorphous carbon coatings using PVD-ARC, the temperature of the carbon layer and the substrate plate rises to over 180°C within a few seconds. However, it has been shown that at higher temperatures, the performance of the coating in terms of electrical conductivity and electrochemical stability drops drastically. If the temperature of the metallic substrate plate, the adhesion promoter layer, and the carbon layer to be formed is kept in the range of 100 to 180°C during carbon coating, electrochemical stability of up to 1.4 volts (up to 6 hours) is achieved. This means that the electrical resistance of the coated substrate plate is comparable to, or even lower than, the resistance of gold foil.

[0010] The measurement of the electrical resistance of the coated substrate plate is carried out according to the following test instructions:

[0011] A measuring system comprising a power source for applying a defined current of 4 amperes, a unit for applying a defined contact force of 60 N / cm 2 , gold-plated measuring stamps with a stamp area of ​​4 cm each 2for the plane-parallel introduction of current and voltage (1 volt) into the coated substrate plate, as well as load cells for determining the contact force. To perform the measurement, the substrate plate is placed between the two measuring stamps, and a layer of gas diffusion felt from the manufacturer Freudenberg, type H14CX483, is inserted between the coated substrate plate and the respective measuring stamp. The stamp surfaces of the two measuring stamps are moved toward each other, compressing the two layers of gas diffusion felt and pressing them against the substrate plate on both sides.

[0012] The measured volume resistance in mQcm 2 is after approximately 20 s of testing time during pressure relief at a value of 40 N / cm 2The volume resistance of the coated substrate plate is in a range that is equal to or lower than the volume resistance of a gold foil measured with the same measuring system under the same measuring conditions.

[0013] The electrochemical resistance of a coated substrate plate is measured at 0.8 V, 1.0 V, 1.2 V, and 1.4 V for 6 hours each, using Ag / AgCl as the reference electrode. The measurement temperature is approximately 80 °C, and the pH is approximately 3.5. The coated substrate plates withstand 1.4 V for 6 hours. A minimum layer thickness of the tetrahedral amorphous carbon layer of 10 nm, hereinafter referred to as the first layer thickness, ensures dense and pore-free layer formation.

[0014] A deposition rate for the carbon layer to be formed is preferably in the range of 40 to about 150 nm*m / min.

[0015] In particular, a PVD inline process is carried out to produce the coated metallic substrate plate. For this purpose, the metallic substrate plate is conveyed, preferably suspended, through sequentially arranged process chambers. The process chambers are separated from one another by vacuum transfer valves, in particular high-vacuum transfer valves. A preferred time for transferring the metallic substrate plate from one process chamber to the adjacent process chamber is preferably a maximum of 40 seconds to avoid cross-contamination of the process chambers.

[0016] Preferably, the process temperature is kept below 180°C by reducing the power density at the ARC source, a targeted selection of the geometric conditions of the PVD system used for coating, an adapted movement method of the substrate plate to be coated in the coating system, targeted cooling measures and a reduction of the layer thickness of the carbon layer.

[0017] In particular, the coating process is deliberately switched off when the temperature of the metallic substrate has reached or exceeded a temperature of approximately 160°C. Furthermore, the process chamber in which the coating takes place can optionally be cooled via built-in cooling plates, which are cooled by means of a cooling medium set to a temperature of, in particular, 4 to 25°C. In addition, at least one empty chamber in which no coating process takes place can optionally be connected between two process chambers to cool the substrate plate in order to keep the temperature of the metallic substrate plate within the desired range during the coating process. Furthermore, the targets are preferably cooled when not in operation (here, the substrates are arranged in front of the targets for additional cooling), which form the material sources for the adhesion promoter layer and the tetrahedral amorphous carbon layer to be formed.

[0018] It has proven to be effective if the adhesion promoter layer is formed with a second layer thickness in the range of 5 to 70 nm.

[0019] The tetrahedral amorphous carbon layer can be constructed from multiple individual layers with a thickness ranging from 5 to 70 nm. This allows for interruptions in the coating process and cooling of the substrate plate so that the maximum temperature of 180°C is not exceeded.

[0020] The metallic substrate plate is preferably mounted in a metallic frame. The frame, including the substrate plate, is then suspended vertically, and the substrate plate is coated in this suspended vertical position. The metallic frame dissipates heat from the substrate plate and serves to cool it.

[0021] The metallic frame preferably covers 7 to 22% of the surface of the substrate plate.

[0022] The ratio of the coatable surface of the substrate plate to the required frame expansion is therefore 78 to 93%, which serves to optimize process heat dissipation. The current flow : current density ratio relative to the substrate plate surface is preferably 0.9 to 4.9 Gb / m 2 (Gb = Gilbert;

[0023] 1 Gilbert / cm = 79.5774715102267 A / m).

[0024] The heat flow density index is preferably 3*10 3 - 6*10 3 W / m 2 The heat flux density describes the heat transferred per transfer area and time interval or the thermal power per area of ​​the substrate plate.

[0025] During the arc vapor deposition (arc PVD) process, the substrate plate is transported through a process chamber along a transport path, preferably at a speed of 0.01 to 0.2 m / s. The transport direction can also be reversed, so that a first tetrahedral amorphous carbon layer is formed during the forward movement, and a second tetrahedral amorphous carbon layer is formed on the first tetrahedral amorphous carbon layer during the return movement within the process chamber. Between two process chambers, for example, in an empty chamber, the substrate plate can be transported more quickly.

[0026] In particular, the metallic substrate plate is used with a temperature in the range of 15 to 120°C at the beginning of the arc evaporation process (Arc-PVD) and a negative voltage in the range of 80 to 220 V is applied to the substrate plate.

[0027] To form the carbon layer, a cathodically poled target, in this case a carbon target, with a purity of 99.9% and a density in the range of 1.66 to 1.95 g / cm 3 and an ash content of less than 500 ppm and a current density based on a total target area of ​​the carbon target during the arc vapor deposition process (Arc-PVD) in the range of 0.006 to 0.026 A / mm 2 A ratio of a width of a target to a distance between the target and a substrate plate is preferably 0.4 to 0.7.

[0028] The arc evaporation process (Arc-PVD) is preferably carried out under argon gas or nitrogen gas, with a partial pressure preferably in the range of 10' 3 up to 10' 2 mbar is selected. During the formation of the carbon layer, a partial pressure for argon in the range of 0.02 to 0.35 Pa and for oxygen at less than 2.5 * 10' 4Pa. In particular, the carbon layer is formed in a process chamber which has the lowest pressure compared to neighboring process chambers, in particular all other process chambers. Preferably, the pressure in the process chamber for forming the carbon layer is a power of ten lower than in an adjacent process chamber. In particular, process chambers arranged in a row are controlled in their pressure values ​​such that they form a pressure cascade in such a way that the pressure is reduced in the direction of the process chamber for forming the carbon layer. Preferably, the pressure always changes by a power of ten between two neighboring process chambers. When a high-vacuum transfer valve is opened between two process chambers, a gas and particle flow always occurs in the direction of the process chamber for forming the carbon layer.Since most of the dust development occurs in the process chamber for forming the carbon layer, the other process chambers are reliably kept dust-free.

[0029] It is preferably an inline coating process, in which per approx. 1 m 3 Chamber volume approx. 1 -3m 2 Coating surface is usable

[0030] During the coating process of the substrate plate with the carbon layer, a current density relative to the substrate surface of 0.9 to 4.9 Gb / m 2not exceeded in order to minimize a temperature increase of the substrate plate. The object is further achieved by a coated metallic substrate plate produced according to the method according to the invention, in particular a coated half-sheet of a bipolar plate, which has a three-dimensionally formed flow field with a channel structure. The electrical volume resistance through the coated substrate plate is comparable to or lower than the electrical volume resistance of a gold foil (see the measurement system for testing described above). Two coated half-sheets are joined by a material bond to form a bipolar plate, in particular by means of a welding process.

[0031] A surface roughness on raised areas of the flow field preferably has an arithmetic mean value of the peak curvature Spc in the range of 1000 to 4500 1 / mm for a measuring area of ​​60 to 65 mm 2This roughness is the result of so-called droplet formation during coating application in combination with the technical roughness of the surface of a substrate plate to be coated. Higher roughness values ​​lead to inhomogeneities in the coating, as it can no longer be formed as a closed layer and adhesion to the substrate plate is reduced. Lower roughness values ​​result in the contact area to adjacent components in an electrochemical cell being too small and thus the contact resistance being too high. The adhesion promoter layer preferably consists of a metal and / or a metal nitride, in particular titanium, a titanium-niobium alloy, titanium nitride, titanium-niobium nitride, chromium or chromium nitride. Combinations of these materials can also be used to promote adhesion.

[0032] An electrochemical cell, in particular a fuel cell, an electrolyzer or a redox flow cell, comprising at least one coated metallic substrate plate produced by the process according to the invention, has proven to be electrochemically particularly stable over the long term.

[0033] The object is achieved for the coating system for carrying out the method according to the invention by comprising:

[0034] - a product carrier which can be transported along a conveyor track and which holds several metal frames including the substrate plates, whereby the metal frames can be suspended vertically on the product carrier,

[0035] - at least one infeed chamber for introducing the product carrier into the coating system and applying a vacuum to the product carrier,

[0036] - several process chambers for carrying out an arc vapor deposition process (Arc-PVD), each comprising at least one cooling plate and several targets, and

[0037] - at least one discharge chamber for discharging the product carrier from the coating system, wherein two successive chambers along the transport path are connected to one another by means of a transfer valve which enables the product carrier to pass from one chamber to the adjacent chamber under vacuum.

[0038] The cooling plates used are preferably coolable by means of a cooling medium, in particular with a temperature in the range of 4 to 25°C. In addition, at least one empty chamber, in which no coating process takes place, can optionally be connected between two process chambers to cool the substrate plate in order to keep the temperature of the metallic substrate plate within the desired range during the coating process. Furthermore, the targets, which form the material sources for the adhesion promoter layer and the tetrahedral amorphous carbon layer to be formed, are preferably coolable in both the operating and non-operating states.

[0039] The metallic frame preferably covers 7 to 22% of the surface of the substrate plate in order to dissipate heat from the substrate plate.

[0040] During the arc vapor deposition (arc PVD) process, the substrate plate can be transported along the conveyor track through the coating system, preferably at a speed of 0.01 to 0.2 m / s. The transport direction can also be reversed, so that a first tetrahedral amorphous carbon layer is formed during the forward movement, and a second tetrahedral amorphous carbon layer is formed on the first tetrahedral amorphous carbon layer during the return movement in the process chamber. The substrate plate can be transported more quickly between two process chambers, for example, in an empty chamber.

[0041] In particular, the carbon layer is formed in a process chamber of the coating system which has the lowest pressure compared to neighbouring process chambers, in particular all other process chambers. Preferably, the pressure in the process chamber for forming the carbon layer is one order of magnitude lower than in an adjacent process chamber. In particular, process chambers arranged in a row are pressure-controlled in such a way that they form a pressure cascade in which the pressure is reduced in the direction of the process chamber for forming the carbon layer. Preferably, the pressure always changes by one order of magnitude between two neighbouring process chambers. When a high-vacuum transfer valve is opened between two process chambers, a gas and particle flow always occurs in the direction of the process chamber for forming the carbon layer.Since most of the dust generation occurs in the process chamber for forming the carbon layer, the other process chambers are reliably kept dust-free. Figures 1 to 4 illustrate the invention by way of example.

[0042] Figure 1 shows a section through a coated metallic substrate plate, Figure 2 shows a schematic three-dimensional view of a bipolar plate,

[0043] Figure 3 is a schematic three-dimensional view of an electrochemical

[0044] cell, and

[0045] Figure 4 shows a longitudinal section through a coating system.

[0046] Figure 1 shows a section through a coated metallic substrate plate 10. This is produced by coating a metallic substrate plate 1 with an adhesion promoter layer 2 in a first surface region using an arc evaporation process (arc PVD). At least one individual layer of a tetrahedral amorphous carbon layer 3 of the ta-C:H type comprising at least 3 wt. % hydrogen is formed on the adhesion promoter layer 2 using the arc evaporation process (arc PVD). The tetrahedral amorphous carbon layer 3 is formed in a first layer thickness in the range of 20 to 500 nm, wherein a temperature of the metallic substrate plate 1, the adhesion promoter layer 2, and the tetrahedral amorphous carbon layer 3 is maintained in the range of 100 to 180°C during coating.

[0047] Figure 2 shows a schematic three-dimensional view of a bipolar plate 12 comprising two embossed, coated half-sheets 11, 11', which are integrally connected, in particular welded, to one another. Each of the half-sheets 11, 11' is formed by a coated metallic substrate plate 10, the uncoated sides of which are in contact with one another. The bipolar plate 12 has media passage openings 15 for passing a cooling medium between the two half-sheets 11, 11' and for supplying reaction media, such as hydrogen and air, to the flow fields 13 arranged on either side of the bipolar plate, each of which corresponds to a region of a half-sheet 11, 11' of the bipolar plate 12 provided with a channel structure 14. In the region of the flow field 13, electrochemical activity occurs in an electrochemical cell 29 (see Figure 3).Figure 3 shows a schematic three-dimensional view of an electrochemical cell 20, here in the form of a low-temperature fuel cell. The electrochemical cell 20 comprises two bipolar plates 12 according to Figure 2 and a membrane electrode assembly 16 comprising a polymer electrolyte membrane arranged between the bipolar plates 12. A cell stack 100 is formed by alternately stacking additional bipolar plates 12 and membrane electrode assemblies 16.

[0048] Figure 4 shows a longitudinal section through a coating system 200. The interior of the existing chambers is visible. An infeed chamber 114, several process chambers 115, 116, 117, and an outfeed chamber 119 are shown here as examples. However, more chambers can also be present, and empty chambers can also be present. Each metallic substrate plate 1, in particular in the form of a half-sheet of a bipolar plate or a bipolar plate made of two half-sheets welded together, is held in a metallic frame 110 and suspended vertically in a product carrier 120. The product carrier 120 is therefore movable, in particular transportable on a transport track 111 through the coating system 200. The product carrier 120 can be transported hanging from a rail or traveling on a floor rail.The product carrier 120 is designed to accommodate a plurality of metallic frames, wherein its dimensions are limited only by the passage opening of the transfer valves and the height and length of the chambers.

[0049] The loaded product carrier 120 is transported via an open transfer valve 118 into the infeed chamber 114, the transfer valve 118 is closed, and the infeed chamber 114 is evacuated. As soon as a vacuum is applied, the transfer valve 118', which follows the transport path 111 of the infeed chamber 114, is opened. The product carrier 120 is transported into the process chamber 115, and the transfer valve 118' between the infeed chamber 114 and the process chamber 115 is closed again. The process chamber 115 is configured for the deposition of the adhesion promoter layer 2 (PVD-Arc) and has several cooled targets 112 for the deposition of adhesion promoter material. Cooling plates 121 are also present in the process chamber 115. In particular, a front and a back of the substrate plate 1 are coated simultaneously.Accordingly, in the coating system 200, the targets 112, 113 and the cooling plates 121 are arranged on the right and left side walls of the process chambers 115, 116, 117, as seen in the direction of the transport path 111.

[0050] As soon as the adhesion promoter layer 2 has been formed in the desired layer thickness, the transfer valve 118" to the process chamber 116 is opened, and the workpiece carrier 120 is transported into the process chamber 116. The process chamber 116 is configured for the deposition of the tetrahedral amorphous carbon layer 3 (PVD-Arc) and has several cooled targets 113 for the deposition of carbon. Furthermore, cooling plates 121 are present in the process chamber 116. An indefinite number of further process chambers 117 with a similar structure can follow the process chamber 116, as shown only schematically here. Empty chambers without targets, which are only equipped with cooling plates 121, can also follow. In particular, an empty chamber is arranged between two process chambers to further cool the loaded workpiece carrier 120. The chambers are each connected via transfer valves.After completion of the tetrahedral amorphous carbon layer 3 (PVD-Arc) in the desired layer thickness, the workpiece carrier 120 is transported from the process chamber 117 via the transfer valve 118"' into the discharge chamber 119 and brought to ambient pressure before being discharged from the coating system 200 via the transfer valve 118"".

[0051] The carbon layer is formed in the process chambers 116, 117 of the coating system 200, which have the lowest pressure compared to neighboring process chambers, in particular all other process chambers. Preferably, the pressure in the process chamber 116 for forming the carbon layer is one order of magnitude lower than in an adjacent process chamber 115, 117. The process chambers 115, 116, 117 arranged in a row are controlled in their pressure values ​​such that they form a pressure cascade in such a way that the pressure is reduced toward the process chamber 116 for forming the carbon layer 3. Preferably, the pressure always changes by a power of ten between two adjacent process chambers 115, 116, 117. When the transfer valve 118" between the two process chambers 115, 116 is opened, a gas and particle flow always occurs in the direction of the process chamber 116 to form the carbon layer.Since most of the dust development usually occurs in the process chamber 116 for forming the carbon layer, the other process chambers 115, 117 are thus reliably kept dust-free.

[0052] List of reference symbols metallic substrate plate

[0053] Adhesion layer tetrahedral amorphous carbon layer (type ta-C:H) coated metallic substrate plate, ir half sheet

[0054] Bipolar plate

[0055] River field

[0056] Channel structure

[0057] Media passage opening

[0058] Membrane electrode assembly electrochemical cell 0 Cell stack 0 Metallic frame 1 Transport track 2 Target for deposition of adhesion promoter material 3 Target for deposition of carbon layers 4 Inlet chamber 5, 116, 117 Process chamber 8, 118', 118", 8'", 118"" Transfer valve 9 Outlet chamber 0 Product carrier 1 Cooling plate 0 Coating system

Claims

Patent claims 1. A method for producing a coated metallic substrate plate (10), in which a metallic substrate plate (1) is coated with an adhesion promoter layer (2) by means of an arc evaporation process (Arc-PVD) in a first surface area, on the adhesion promoter layer (2) by means of the arc evaporation process (Arc-PVD) at least one single layer of a tetrahedral amorphous carbon layer (3) of the type ta-C:H comprising at least 3 wt.% hydrogen is formed in a first layer thickness in the range of 10 to 500 nm, wherein a temperature of the metallic substrate plate (1), the adhesion promoter layer (2) and the tetrahedral amorphous carbon layer (3) is maintained in the range of 100 to 180°C during coating.

2. The method according to claim 1, wherein the adhesion promoter layer (2) is formed with a second layer thickness in the range from 5 nm to 5 pm.

3. The method according to claim 1 or 2, wherein the tetrahedral amorphous carbon layer (3) is constructed from a plurality of individual layers with an individual layer thickness in the range of 5 to 70 nm.

4. Method according to one of claims 1 to 3, wherein the substrate plate (1) is fastened in a metallic frame (110), the frame (110) including the substrate plate (1) is then suspended vertically and the substrate plate (1) is coated in this suspended vertical position.

5. The method according to any one of claims 1 to 4, wherein the substrate plate (1) is transported along a transport path (111) at a speed of 0.01 to 0.2 m / s during the arc evaporation process (Arc-PVD).

6. The method according to any one of claims 1 to 5, wherein the substrate plate (1) is used at a temperature in the range of 15 to 120 °C at the beginning of the arc evaporation process (Arc-PVD) and that a negative voltage in the range of 80 to 220 V is applied to the substrate plate (1).

7. Method according to one of claims 1 to 6, wherein for forming the carbon layer (3) a cathodically poled target (113) made of carbon with a purity of 99.9% and a density in the range of 1.66 to 1.95 g / cm 3 and an ash content of less than 500 ppm, and wherein a current density based on a total target area of ​​the target (113) during the arc vapor deposition process (Arc-PVD) is in the range of 0.006 to 0.026 A / mm 2 is chosen.

8. The method according to any one of claims 1 to 7, wherein the arc vapor deposition process (Arc-PVD) is carried out under argon gas, wherein a partial pressure during the formation of the carbon layer (3) for argon is in the range of 0.02 to 0.35 Pa and for oxygen is less than 2.5 * 10' 4 Pa is set.

9. Coated metallic substrate plate (10), in particular coated half-sheet (11) of a bipolar plate (12) or coated bipolar plate (12), produced by a method according to one of claims 1 to 8, which has a three-dimensionally formed flow field (13) with a channel structure (14).

10. Coated metallic substrate plate (10) according to claim 9, wherein a surface roughness on raised areas of the flow field (13) has an arithmetic mean value of the peak curvature Spc in the range of 1000 to 4500 1 / mm for a measuring area of ​​60 to 65 mm 2 has.

11. Coated metallic substrate plate (10) according to claim 9 or 10, wherein the adhesion promoter layer (2) consists of at least one metal and / or a metal nitride, in particular made of titanium, a titanium-niobium alloy, titanium nitride, titanium niobium nitride, chromium or chromium nitride.

12. Electrochemical cell (20), in particular fuel cell, electrolyzer or redox flow cell, comprising at least one coated metallic substrate plate (10) according to one of claims 9 to 11.

13. Coating system (200) for carrying out a method according to one of claims 1 to 8, which comprises: - a product carrier (120) transportable along a transport track (111) for receiving a plurality of metallic frames (110) including the substrate plates (1), wherein the metallic frames (110) can be suspended vertically on the product carrier (120), - at least one inlet chamber (114) for introducing the product carrier (120) into the coating system (200) and applying a vacuum to the product carrier (120), - a plurality of process chambers (115, 116, 117) for carrying out an arc vapor deposition process (Arc-PVD), each comprising at least one cooling plate (121) and a plurality of targets (112, 113), and - at least one discharge chamber for discharging the product carrier (120) from the coating system (200), wherein two successive chambers (114, 115; 115, 116; 116, 117; 117, 119) along the transport path (111) are connected to one another by means of a transfer valve (118) which enables the product carrier (121) to pass from one chamber (114, 115, 116, 117) to the adjacent chamber (115, 116, 117, 119) under vacuum.

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