Preparation method of metal bipolar plate coating and metal bipolar plate

Abstract

The embodiment of the invention discloses a preparation method of a metal bipolar plate coating and a metal bipolar plate. The method comprises the following steps: providing the metal bipolar plate; performing magnetron sputtering ion deposition on the metal bipolar plate to obtain a metal bipolar plate with a magnetron sputtering ion deposition layer; sequentially carrying out magnetron sputtering ion deposition and arc ion deposition on the metal bipolar plate with the magnetron sputtering ion deposition layer to obtain a metal bipolar plate with an intermediate layer; and performing arc ion deposition on the metal bipolar plate with the intermediate layer to obtain the metal bipolar plate with the coating structure. According to the preparation method of the metal bipolar plate coating, through the coating preparation method combining the magnetron sputtering deposition process and the arc deposition process, interface matching between the coatings is guaranteed, the overall structure of the coating is optimized, so that the prepared coating has high compactness and uniformity, and the service life of the metal bipolar plate is prolonged.

Description

Technical Field

[0001] This invention relates to the field of proton exchange membrane fuel cells, and particularly to a method for preparing a metal bipolar plate coating and a metal bipolar plate. Background Technology

[0002] The fuel cell stack is the core component of a fuel cell, mainly composed of bipolar plates, membrane electrode assemblies (MEAs), and busbars. Bipolar plates provide a gas path, prevent hydrogen and oxygen from mixing in the fuel cell, and establish a current path between the series-connected anode and cathode. Bipolar plates can be mainly classified into graphite materials, metallic materials, and composite materials. Among these, metallic bipolar plates are easy to process, can be mass-produced, have low cost, are thin, and result in high volumetric power density and specific energy. However, metallic bipolar plates have poor corrosion resistance and are prone to the precipitation of iron and other metal ions, leading to MEA failure. Therefore, metallic bipolar plates need to be modified to ensure corrosion resistance.

[0003] Currently, one or more protective layers are typically coated onto the surface of metal bipolar plates to prevent contact between the substrate material and corrosive media. These coatings are applied to the substrate material surface using specialized processes, such as physical vapor deposition (PVD), chemical vapor deposition (CVD), and plasma spraying. PVD primarily includes magnetron sputtering ion deposition and arc ion deposition. Magnetron sputtering produces coatings with easily controllable composition and good structural uniformity, but suffers from low ion energy, low ionization rate, and low coating density. Arc ion deposition, due to its high ion ionization energy and high ionization rate, can efficiently obtain highly dense coating structures, but the resulting coatings exhibit poor uniformity.

[0004] Therefore, it is particularly important to develop a method for preparing metal bipolar plate coatings that combines the advantages of magnetron sputtering ion deposition and arc ion deposition to achieve the preparation of composite coating structures, thereby obtaining coatings with high density, high uniformity and high corrosion resistance. Summary of the Invention

[0005] To address the aforementioned technical problems, this application provides a method for preparing a metal bipolar plate coating. By combining magnetron sputtering ion deposition and arc ion deposition processes, a composite coating structure is prepared, which solves the current problem of lacking a method for preparing a metal bipolar plate composite coating structure that can obtain a coating with high density, high uniformity, and high corrosion resistance.

[0006] The technical solution provided in this application is as follows: On one hand, this application provides a method for preparing a metal bipolar plate coating, the method comprising: Provide metal bipolar plates; The metal bipolar plate is subjected to magnetron sputtering ion deposition to obtain a metal bipolar plate with a magnetron sputtering ion deposition layer. The metal bipolar plate with the magnetron sputtering ion deposition layer is subjected to magnetron sputtering ion deposition and arc ion deposition in sequence to obtain a metal bipolar plate with an intermediate layer. Arc ion deposition is performed on the metal bipolar plate with the intermediate layer to obtain a metal bipolar plate with a coating structure.

[0007] In some optional embodiments, the metal bipolar plate includes a cathode surface and an anode surface, and the step of performing magnetron sputtering ion deposition on the metal bipolar plate to obtain a metal bipolar plate with a magnetron sputtering ion deposition layer includes: A first magnetron sputtering ion deposition is performed on the cathode surface to prepare a first magnetron sputtering ion deposition layer; simultaneously, a first magnetron sputtering ion deposition is performed on the anode surface to prepare a second magnetron sputtering ion deposition layer. A second magnetron sputtering ion deposition is performed on the surface of the first magnetron sputtering ion deposition layer away from the cathode surface to prepare a third magnetron sputtering ion deposition layer; simultaneously, a second magnetron sputtering ion deposition is performed on the surface of the second magnetron sputtering ion deposition layer away from the anode surface to prepare a fourth magnetron sputtering ion deposition layer, thereby obtaining a metal bipolar plate with magnetron sputtering ion deposition layers.

[0008] In some optional embodiments, the first magnetron sputtering ion deposition layer is one or more of chromium, titanium, and niobium, the thickness of the first magnetron sputtering ion deposition layer and the second magnetron sputtering ion deposition layer is 10nm-500nm, and the deposition power of the first magnetron sputtering ion deposition is 10W-5000W.

[0009] In some optional embodiments, the second magnetron sputtering ion deposition layer is any one of Cr-NC, Ti-CN, and NbN, the thickness of the third and fourth magnetron sputtering ion deposition layers is 10nm-500nm, and the deposition power of the second magnetron sputtering ion deposition is 10W-5000W.

[0010] In some optional embodiments, the step of sequentially performing magnetron sputtering ion deposition and arc ion deposition on the metal bipolar plate with the magnetron sputtering ion deposition layer to obtain a metal bipolar plate with an intermediate layer includes: A third magnetron sputtering ion deposition and a first arc ion deposition are sequentially performed on the surface of the third magnetron sputtering ion deposition layer away from the cathode surface to prepare a first intermediate layer. Simultaneously, a third magnetron sputtering ion deposition and a first arc ion deposition are sequentially performed on the surface of the fourth magnetron sputtering ion deposition layer away from the anode surface to prepare a second intermediate layer, thereby obtaining a metal bipolar plate with an intermediate layer.

[0011] In some optional embodiments, the third magnetron sputtered ion deposition layer is any one of Cr-NC, Ti-CN, and NbN, the first arc ion deposition layer is C, and the intermediate layer is any one of Cr-NC / C, Ti-CN / C, and NbN / C.

[0012] In some optional embodiments, the thickness of the intermediate layer is 10nm-100nm, the deposition power of the third magnetron sputtering ion deposition is 10W-5000W, and the deposition power of the first arc ion deposition is 10W-5000W.

[0013] In some optional embodiments, the step of performing arc ion deposition on the metal bipolar plate with the intermediate layer to obtain a metal bipolar plate with a coating structure includes: A second arc ion deposition is performed on the surface of the first intermediate layer away from the cathode surface to prepare a first arc ion deposition layer. Simultaneously, a second arc ion deposition is performed on the surface of the second intermediate layer away from the anode surface to prepare a second arc ion deposition layer, resulting in a metal bipolar plate with a coating structure.

[0014] In some optional embodiments, the second arc ion deposition layer is either C or N, the thickness of the first intermediate layer and the second intermediate layer is 10nm-500nm, and the deposition power of the second arc ion deposition is 10W-5000W.

[0015] On the other hand, this application provides a metal bipolar plate, the metal bipolar plate comprising a metal bipolar plate coating prepared by the preparation method as described in any one of the above embodiments.

[0016] The method for preparing a metal bipolar plate coating provided in this application includes providing a metal bipolar plate; performing magnetron sputtering ion deposition on the metal bipolar plate to obtain a metal bipolar plate with a magnetron sputtering ion deposition layer; sequentially performing magnetron sputtering ion deposition and arc ion deposition on the metal bipolar plate with the magnetron sputtering ion deposition layer to obtain a metal bipolar plate with an intermediate layer; and performing arc ion deposition on the metal bipolar plate with the intermediate layer to obtain a metal bipolar plate with a coating structure. By combining magnetron sputtering ion deposition and arc ion deposition processes to prepare a composite coating structure, the interface matching between coatings is ensured, the overall coating structure is optimized, and thus a metal bipolar plate coating with high density, high uniformity, and high corrosion resistance is obtained. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a flowchart of a method for preparing a metal bipolar plate coating according to an embodiment of the present invention; Figure 2 This is a flowchart illustrating the fabrication process of a metal bipolar plate according to an embodiment of the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0020] The term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of this application. In the description of this application, it should be understood that the terms "upper," "lower," "top," "bottom," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Moreover, the terms "first," "second," etc., are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein.

[0021] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to an integer, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are included. For example, a specified range from “1 to 10” should be considered to include any and all subranges between the minimum value 1 and the maximum value 10. Exemplary subranges of the range 1 to 10 include, but are not limited to, 1 to 6.1, 3.5 to 7.8, 5.5 to 10, etc.

[0022] Because the coating composition prepared by magnetron sputtering technology is easy to control and has good structural uniformity, but the ion energy is low, the ionization rate is not high, and the coating density is low, while the arc ion deposition technology can obtain a high-density coating structure with high ion ion energy and high ionization rate, but the coating uniformity is poor. Therefore, in order to combine the advantages of magnetron sputtering ion deposition and arc ion deposition technology to prepare a composite coating structure, thereby obtaining a metal bipolar plate coating with high density, high uniformity and high corrosion resistance, this application provides a method for preparing a metal bipolar plate coating.

[0023] Please see Figure 1 , Figure 1 This is a flowchart of a method for preparing a metal bipolar plate coating according to an embodiment of the present invention. In one aspect, this application provides a method for preparing a metal bipolar plate coating, the method comprising: S101. Provides metal bipolar plates.

[0024] Optionally, please refer to Figure 2 , Figure 2 This is a flowchart of the preparation process of a metal bipolar plate according to an embodiment of the present invention. As shown in the figure, the substrate is first prepared. It is necessary to select a suitable bipolar plate substrate, such as stainless steel, titanium alloy and other metal materials. The selection can be made according to actual business needs and is not limited here. For example, stainless steel has good conductivity, processability and certain corrosion resistance. When selecting a graphite bipolar plate, high-purity graphite material is mainly selected.

[0025] Optionally, substrate preparation also includes preliminary treatment of the material's size and shape. Metal sheets can be cut into plates conforming to the design dimensions of the metal bipolar plate, or graphite blocks can be machined into blanks approximating the shape of the metal bipolar plate. Simultaneously, the substrate should be preliminarily cleaned to remove surface oil, dust, and other impurities to ensure the quality of subsequent processing.

[0026] Optionally, the substrate is stamped to form the basic shape of the bipolar plate, including the flow channel shape and preliminary outlines of some sealing structures. If the substrate is metal, a high-precision stamping die is required during the stamping process, and the shape of the die must match the flow channel and sealing structure of the bipolar plate.

[0027] Optionally, welding can be performed after the stamping operation to connect the stamped components. In the fabrication of metal bipolar plates, it may be necessary to weld multiple layers of metal sheets together to increase the thickness and strength of the bipolar plate.

[0028] Optionally, the welded metal bipolar plate can undergo substrate pretreatment, for example, surface cleaning and roughening. The cleaning process can employ chemical cleaning methods to remove welding residues, oxides, and other impurities from the surface. Pretreatment can result in a smoother, cleaner surface, which is beneficial for coating preparation on the substrate surface.

[0029] S102. Perform magnetron sputtering ion deposition on the metal bipolar plate to obtain a metal bipolar plate with a magnetron sputtering ion deposition layer.

[0030] Alternatively, magnetron sputtering ion deposition technology utilizes high-energy ions to bombard the surface of a target material, causing the target atoms to be sputtered out and deposited on the substrate surface to form a thin film. By controlling the movement of electrons through a magnetic field, the plasma density and sputtering efficiency can be significantly improved. The thin film deposition is uniform and the thickness is controllable, making it suitable for preparing large-area thin films.

[0031] In an optional embodiment, the metal bipolar plate includes a cathode surface and an anode surface, and the step of performing magnetron sputtering ion deposition on the metal bipolar plate to obtain a metal bipolar plate with a magnetron sputtering ion deposition layer includes: A first magnetron sputtering ion deposition is performed on the cathode surface to prepare a first magnetron sputtering ion deposition layer; simultaneously, a first magnetron sputtering ion deposition is performed on the anode surface to prepare a second magnetron sputtering ion deposition layer. A second magnetron sputtering ion deposition is performed on the surface of the first magnetron sputtering ion deposition layer away from the cathode surface to prepare a third magnetron sputtering ion deposition layer; simultaneously, a second magnetron sputtering ion deposition is performed on the surface of the second magnetron sputtering ion deposition layer away from the anode surface to prepare a fourth magnetron sputtering ion deposition layer, thereby obtaining a metal bipolar plate with magnetron sputtering ion deposition layers.

[0032] In an optional embodiment, the first magnetron sputtering ion deposition layer is one or more of chromium, titanium, and niobium, the thickness of the first magnetron sputtering ion deposition layer and the second magnetron sputtering ion deposition layer is 10nm-500nm, and the deposition power of the first magnetron sputtering ion deposition is 10W-5000W.

[0033] In an optional embodiment, the second magnetron sputtering ion deposition layer is any one of Cr-NC, Ti-CN, and NbN, the thickness of the third and fourth magnetron sputtering ion deposition layers is 10nm-500nm, and the deposition power of the second magnetron sputtering ion deposition is 10W-5000W.

[0034] Optionally, the metal bipolar plate consists of an anode surface and a cathode surface, which are connected together by stamping or welding. The orientation of the anode and cathode surfaces of the metal bipolar plate depends on the design and assembly method of the fuel cell stack. The metal bipolar plates are stacked in series, and each metal bipolar plate serves as both the anode and cathode plate of an adjacent single cell. The anode surface of the metal bipolar plate faces the hydrogen channel, and the cathode surface faces the air channel.

[0035] Optionally, a first magnetron sputtering ion deposition layer and a second magnetron sputtering ion deposition layer are simultaneously prepared on the metal bipolar plate, including the cathode surface and the anode surface, using magnetron sputtering ion deposition technology. The first magnetron sputtering ion deposition layer and the second magnetron sputtering ion deposition layer have the same thickness and the same deposition parameters during the preparation process.

[0036] Optionally, a third magnetron sputtering ion deposition layer is prepared on the basis of the first magnetron sputtering ion deposition layer, and a fourth magnetron sputtering ion deposition layer is prepared on the basis of the second magnetron sputtering ion deposition layer. The third magnetron sputtering ion deposition layer and the fourth magnetron sputtering ion deposition layer have the same thickness and the same deposition parameters during the preparation process.

[0037] Optionally, the target material for the first magnetron sputtering ion deposition layer is one or more of Cr, Ti, and Nb. The first magnetron sputtering ion deposition layer is deposited on the cathode surface of the metal bipolar plate using a selected metal target material, while a second magnetron sputtering ion deposition layer is deposited on the anode surface of the metal bipolar plate.

[0038] Optionally, the thicknesses of the first magnetron sputtering ion deposition layer and the second magnetron sputtering ion deposition layer, as well as the deposition power and deposition time of the first magnetron sputtering ion deposition, can be set according to actual business needs and are not limited here.

[0039] Optionally, the second magnetron sputtered ion deposition layer is any one of Cr-NC, Ti-CN, and NbN, and a metal target and a magnetron sputtered carbon target can be selected as the deposition source. At the same time, a third magnetron sputtered ion deposition layer is deposited on the surface of the first magnetron sputtered ion deposition layer, and a fourth magnetron sputtered ion deposition layer is deposited on the surface of the second magnetron sputtered ion deposition layer.

[0040] Optionally, the thickness of the third magnetron sputtering ion deposition layer, the thickness of the fourth magnetron sputtering ion deposition layer, and the deposition power and deposition time of the second magnetron sputtering ion deposition can be set according to actual business needs, and are not limited here.

[0041] Optionally, the first magnetron sputtered ion deposition layer can serve as a base layer, providing a smooth and uniform surface for subsequent coating deposition. The second magnetron sputtered compound layer further stabilizes the coating structure, providing a good bonding foundation for subsequent intermediate layers and arc ion deposition, thereby improving the overall adhesion of the coating. Through this two-layer magnetron sputtered ion deposition structure, different coating compositions and structures can be formed on the substrate surface. For example, the first layer is a metal layer, and the second layer is a metal compound layer. This structure provides good conductivity and corrosion resistance, while also reducing interlayer stress and improving the overall performance of the coating. The magnetron sputtered deposited coating has high density and uniformity, which can block the contact between the substrate material and the corrosive medium, reducing the amount of metal ions deposited in the substrate, thereby improving the service life of the electrodes and plates.

[0042] S103. The metal bipolar plate with the magnetron sputtering ion deposition layer is subjected to magnetron sputtering ion deposition and arc ion deposition in sequence to obtain a metal bipolar plate with an intermediate layer.

[0043] In an optional embodiment, the step of sequentially performing magnetron sputtering ion deposition and arc ion deposition on the metal bipolar plate with the magnetron sputtering ion deposition layer to obtain a metal bipolar plate with an intermediate layer includes: A third magnetron sputtering ion deposition and a first arc ion deposition are sequentially performed on the surface of the third magnetron sputtering ion deposition layer away from the cathode surface to prepare a first intermediate layer. Simultaneously, a third magnetron sputtering ion deposition and a first arc ion deposition are sequentially performed on the surface of the fourth magnetron sputtering ion deposition layer away from the anode surface to prepare a second intermediate layer, thereby obtaining a metal bipolar plate with an intermediate layer.

[0044] In an optional embodiment, the third magnetron sputtered ion deposition layer is any one of Cr-NC, Ti-CN, and NbN, the first arc ion deposition layer is C, and the intermediate layer is any one of Cr-NC / C, Ti-CN / C, and NbN / C.

[0045] In an optional embodiment, the thickness of the intermediate layer is 10nm-100nm, the deposition power of the third magnetron sputtering ion deposition is 10W-5000W, and the deposition power of the first arc ion deposition is 10W-5000W.

[0046] Optionally, the intermediate layer is a matching layer used to match the magnetron sputtering ion deposition layer and the arc ion deposition layer, reducing the stress between them. The first intermediate layer and the second intermediate layer are prepared by simultaneously passing the third magnetron sputtering ion deposition and the first arc ion deposition on the third magnetron sputtering ion deposition layer and the fourth magnetron sputtering ion deposition layer, respectively.

[0047] Optionally, a first intermediate layer and a second intermediate layer can be prepared by using a magnetron sputtering metal target, a magnetron sputtering carbon target, and a cathode arc carbon target as deposition sources for magnetron sputtering ion deposition and arc ion deposition.

[0048] Optionally, the thickness of the first intermediate layer and the second intermediate layer, the deposition power of the third magnetron sputtering ion deposition, the deposition power of the first arc ion deposition, and the deposition time can be set according to actual business needs, and are not limited here.

[0049] The intermediate layer serves as a transition between the magnetron sputtering ion deposition layer and the arc ion deposition layer, enabling better bonding between the two and ensuring a smooth coating preparation process. Simultaneously, the differences in deposition rates and ion energies between magnetron sputtering and arc deposition processes can lead to residual stress within the coating. The intermediate layer, through its structural and performance characteristics, can regulate and buffer the stress generated by these two processes, reducing stress differences within the coating and preventing problems such as cracking and peeling caused by excessive stress. This enhances the bonding strength between the coating and the substrate, as well as between coating layers. Furthermore, the intermediate layer can fill any pores and defects that may exist between the magnetron sputtering layer and the arc deposition layer, making the coating denser and further improving its corrosion resistance and protective performance, while reducing the penetration path of corrosive media.

[0050] S104. Perform arc ion deposition on the metal bipolar plate with the intermediate layer to obtain a metal bipolar plate with a coating structure.

[0051] In an optional embodiment, the step of performing arc ion deposition on the metal bipolar plate with the intermediate layer to obtain a metal bipolar plate with a coating structure includes: A second arc ion deposition is performed on the surface of the first intermediate layer away from the cathode surface to prepare a first arc ion deposition layer. Simultaneously, a second arc ion deposition is performed on the surface of the second intermediate layer away from the anode surface to prepare a second arc ion deposition layer, resulting in a metal bipolar plate with a coating structure.

[0052] In an optional embodiment, the second arc ion deposition layer is either C or N, the thickness of the first intermediate layer and the second intermediate layer is 10nm-500nm, and the deposition power of the second arc ion deposition is 10W-5000W.

[0053] Optionally, a second arc ion deposition is performed simultaneously on the surfaces of the first intermediate layer and the second intermediate layer to prepare the first arc ion deposition layer and the second arc ion deposition layer, respectively. The target material for the second arc ion deposition can be a cathode arc carbon target.

[0054] Optionally, the deposition power and deposition time of the second arc ion deposition, as well as the thickness of the first and second arc ion deposition layers, can be set according to actual business needs, and are not limited here.

[0055] Optionally, the coating process is performed after the pretreatment and before the sealing process; applying a functional coating of a certain thickness to the substrate surface can improve the overall performance of the metal bipolar plate in the fuel cell operating environment.

[0056] Optionally, after the coating of the metal bipolar plate is prepared, the metal bipolar plate can be sealed to prevent electrolyte leakage between the bipolar plates, while also ensuring good electrical insulation between them. For example, sealant or gaskets can be used for sealing. The sealant is evenly applied to the sealing area of ​​the bipolar plate, and then the bipolar plates are assembled together. The sealant is then cured under pressure to form a sealed structure. Alternatively, a suitable gasket, such as silicone rubber or other materials with good elasticity and corrosion resistance, can be selected. The gasket is placed in the sealing groove of the bipolar plate, and then assembled, relying on the elastic deformation of the gasket to achieve a seal.

[0057] Optionally, after the metal bipolar plate is fabricated, it can be inspected. The inspection may include visual inspection, dimensional inspection, and performance testing. For example, visual inspection mainly checks for scratches, coating peeling, welding defects, etc., on the surface of the bipolar plate; dimensional inspection accurately measures parameters such as the thickness and flow channel dimensions of the bipolar plate to ensure it meets design requirements; performance testing includes corrosion resistance testing and conductivity testing. Corrosion resistance testing involves immersing the bipolar plate in a simulated electrolyte environment and observing the corrosion status by measuring the amount of ion deposition after a certain period; conductivity testing can measure the resistivity of the bipolar plate using methods such as the four-probe method to evaluate its conductivity.

[0058] The following is a general description of the high-temperature fuel cell catalyst preparation method provided in the embodiments of this application: A first magnetron sputtering ion deposition layer is deposited on the cathode surface of a metal bipolar plate using a metal target, while a second magnetron sputtering ion deposition layer is deposited on the anode surface of the metal bipolar plate. Select a metal target and other magnetron sputtering targets as deposition sources, deposit a third magnetron sputtering ion deposition layer on the surface of the first magnetron sputtering ion deposition layer, and simultaneously deposit a fourth magnetron sputtering ion deposition layer on the surface of the second magnetron sputtering ion deposition layer. The first intermediate layer and the second intermediate layer are prepared by simultaneously passing the third magnetron sputtering ion deposition and the first arc ion deposition on the third magnetron sputtering ion deposition layer and the fourth magnetron sputtering ion deposition layer, respectively. A second arc ion deposition is performed simultaneously on the surfaces of the first intermediate layer and the second intermediate layer to prepare the first arc ion deposition layer and the second arc ion deposition layer, respectively, thus obtaining a metal bipolar plate with a coating structure.

[0059] In an optional embodiment, this application provides a metal bipolar plate comprising a metal bipolar plate coating prepared using the preparation method described in any of the preceding claims.

[0060] Example 1: This embodiment provides a metal bipolar plate, which includes a metal substrate and a metal bipolar plate coating; the metal substrate is made of 316L stainless steel; the first magnetron sputtered ion deposition layer and the second magnetron sputtered ion deposition layer are magnetron sputtered Cr metal layers with a thickness of 100 nm; the first magnetron sputtered ion deposition layer and the second magnetron sputtered ion deposition layer are magnetron sputtered CrC compound layers with a thickness of 50 nm; the first intermediate layer and the second intermediate layer are magnetron sputtered CrC and cathode arc carbon layers with a thickness of 30 nm; the first arc ion deposition layer and the second arc ion deposition layer are arc ion deposited carbon layers with a thickness of 250 nm.

[0061] The preparation method of the coating on the metal bipolar plate specifically includes the following steps: (1) Using a magnetron sputtering Cr target as the deposition source, at a deposition power of 1000W and a deposition current of 10A, a metal Cr layer was deposited on both sides of the metal substrate for 30 minutes to prepare the first magnetron sputtering ion deposition layer and the second magnetron sputtering ion deposition layer. (2) Using a magnetron sputtering Cr target and a magnetron sputtering carbon target as deposition sources, a Cr target deposition power of 1000W and a deposition current of 10A are used, and a carbon target deposition power of 1500W and a deposition current of 10A are used for deposition for 10 minutes, thereby depositing a compound CrC layer on the surface of the first magnetron sputtering ion deposition layer and the second magnetron sputtering ion deposition layer, and preparing a third magnetron sputtering ion deposition layer and a fourth magnetron sputtering ion deposition layer. (3) Using a magnetron sputtering Cr target, a magnetron sputtering carbon target, and a cathode arc carbon target as deposition sources, the magnetron sputtering Cr target deposition power is 500W and the deposition current is 8A, the magnetron sputtering carbon target deposition power is 800W and the deposition current is 6A, and the cathode arc carbon target deposition power is 1000W, and the deposition time is 10min, thereby depositing the compound CrC and carbon matching layer on the surface of the third magnetron sputtering ion deposition layer and the fourth magnetron sputtering ion deposition layer, and preparing the first intermediate layer and the second intermediate layer; (4) Using a cathode arc carbon target as the deposition source, a carbon layer is deposited on the surface of the first intermediate layer and the second intermediate layer at a deposition power of 2000W for 20 minutes to prepare the first arc ion deposition layer and the second arc ion deposition layer, thus obtaining a metal bipolar plate with a coating structure.

[0062] Example 2: This embodiment provides a metal bipolar plate, which includes a metal substrate and a metal bipolar plate coating; the metal substrate is made of 316L stainless steel; the first magnetron sputtered ion deposition layer and the second magnetron sputtered ion deposition layer are magnetron sputtered metal Ti layers with a thickness of 100 nm; the first magnetron sputtered ion deposition layer and the second magnetron sputtered ion deposition layer are magnetron sputtered TiC compound layers with a thickness of 50 nm; the first intermediate layer and the second intermediate layer are magnetron sputtered TiC and cathode arc carbon layers with a thickness of 30 nm; the first arc ion deposition layer and the second arc ion deposition layer are arc ion deposited carbon layers with a thickness of 250 nm.

[0063] The preparation method of the coating on the metal bipolar plate specifically includes the following steps: (1) Using a magnetron sputtering Ti target as the deposition source, at a deposition power of 1500W and a deposition current of 10A, a metal Ti layer was deposited on both sides of the metal substrate for 30 minutes to prepare the first magnetron sputtering ion deposition layer and the second magnetron sputtering ion deposition layer. (2) Using a magnetron sputtering Ti target and a magnetron sputtering carbon target as deposition sources, a Ti target deposition power of 1500W and a deposition current of 10A and a carbon target deposition power of 1500W and a deposition current of 10A were deposited for 10 minutes to deposit a compound TiC layer on the surface of the first magnetron sputtering ion deposition layer and the second magnetron sputtering ion deposition layer, thereby preparing a third magnetron sputtering ion deposition layer and a fourth magnetron sputtering ion deposition layer. (3) Using a magnetron sputtering Ti target, a magnetron sputtering carbon target, and a cathode arc carbon target as deposition sources, the magnetron sputtering Ti target deposition power is 1000W and the deposition current is 8A, the magnetron sputtering carbon target deposition power is 800W and the deposition current is 6A, and the cathode arc carbon target deposition power is 1000W, and the deposition time is 10min, thereby depositing compound TiC and carbon matching layer on the surface of the third magnetron sputtering ion deposition layer and the fourth magnetron sputtering ion deposition layer, and preparing the first intermediate layer and the second intermediate layer; (4) Using a cathode arc carbon target as the deposition source, a carbon layer is deposited on the surface of the first intermediate layer and the second intermediate layer at a deposition power of 2000W for 20 minutes to prepare the first arc ion deposition layer and the second arc ion deposition layer, thus obtaining a metal bipolar plate with a coating structure.

[0064] Example 3: This embodiment provides a metal bipolar plate, which includes a metal substrate and a metal bipolar plate coating; the metal substrate is made of 316L stainless steel; the first magnetron sputtered ion deposition layer and the second magnetron sputtered ion deposition layer are magnetron sputtered metal Ti layers with a thickness of 100 nm; the first magnetron sputtered ion deposition layer and the second magnetron sputtered ion deposition layer are magnetron sputtered TiC compound layers with a thickness of 100 nm; the first intermediate layer and the second intermediate layer are magnetron sputtered TiC and cathode arc carbon layers with a thickness of 30 nm; the first arc ion deposition layer and the second arc ion deposition layer are arc ion deposited carbon layers with a thickness of 250 nm.

[0065] The preparation method of the coating on the metal bipolar plate specifically includes the following steps: (1) Using a magnetron sputtering Ti target as the deposition source, at a deposition power of 3000W and a deposition current of 18A, a metal Ti layer was deposited on both sides of the metal substrate for 10 minutes to prepare the first magnetron sputtering ion deposition layer and the second magnetron sputtering ion deposition layer. (2) Using a magnetron sputtering Ti target and a magnetron sputtering carbon target as deposition sources, a Ti target deposition power of 3000W and a deposition current of 18A were used, and a carbon target deposition power of 2000W and a deposition current of 12A were used for deposition for 10 minutes, thereby depositing a compound TiC layer on the surface of the first magnetron sputtering ion deposition layer and the second magnetron sputtering ion deposition layer, and preparing a third magnetron sputtering ion deposition layer and a fourth magnetron sputtering ion deposition layer. (3) Using a magnetron sputtering Ti target, a magnetron sputtering carbon target, and a cathode arc carbon target as deposition sources, the magnetron sputtering Ti target deposition power is 1200W and the deposition current is 8A, the magnetron sputtering carbon target deposition power is 1000W and the deposition current is 7A, and the cathode arc carbon target deposition power is 2000W, and the deposition time is 5min, thereby depositing compound TiC and carbon matching layer on the surface of the third magnetron sputtering ion deposition layer and the fourth magnetron sputtering ion deposition layer, and preparing the first intermediate layer and the second intermediate layer; (4) Using a cathode arc carbon target as the deposition source, a carbon layer is deposited on the surface of the first intermediate layer and the second intermediate layer at a deposition power of 4000W for 10 minutes to prepare the first arc ion deposition layer and the second arc ion deposition layer, thus obtaining a metal bipolar plate with a coating structure.

[0066] The metal bipolar plates prepared in the above embodiments were tested according to national standards, including the following steps: the electrochemical workstation was used to perform constant potential scanning on the sample of the embodiment. The corrosion solution was a mixture of sulfuric acid with pH=3 and 5ppm hydrofluoric acid solution. The test time was greater than 90h, the test potential was 0.9V vs. SHE, and the test temperature was 80℃. The solution after the test was tested, and the total absolute number of different metal ions precipitated per unit time and per unit area was counted to evaluate the corrosion resistance of the metal bipolar plate.

[0067] Please refer to Table 1. Table 1 compares the amount of ion deposition in the corrosive solution of the metal bipolar plates obtained according to the preparation methods of Examples 1, 2, and 3. As can be seen from the data in the table, the preparation method of the metal bipolar plate coating proposed in this invention achieves the preparation of a composite coating structure by combining magnetron sputtering ion deposition and arc ion deposition processes. The amount of metal ion deposition can be reduced by one order of magnitude compared with the single process. It can be seen that the metal bipolar plate prepared by the preparation method proposed in this invention not only has high density and uniformity, but also high corrosion resistance and longer service life.

[0068] Table 1

[0069] The method for preparing a metal bipolar plate coating provided in this application includes: providing a metal bipolar plate; performing magnetron sputtering ion deposition on the metal bipolar plate to obtain a metal bipolar plate with a magnetron sputtering ion deposition layer; sequentially performing magnetron sputtering ion deposition and arc ion deposition on the metal bipolar plate with the magnetron sputtering ion deposition layer to obtain a metal bipolar plate with an intermediate layer; and performing arc ion deposition on the metal bipolar plate with the intermediate layer to obtain a metal bipolar plate with a coating structure. The method for preparing a metal bipolar plate coating provided in this application has the following beneficial effects: (1) By utilizing the technical advantages of magnetron sputtering ion deposition and arc ion deposition processes, a multilayer composite coating structure design under the two preparation processes is realized to form a highly dense coating and reduce the amount of metal ion corrosion precipitation; (2) By controlling the parameters of the two deposition processes, the interfacial structure matching between coatings under different preparation processes is improved, the interlayer stress is reduced, and the bonding strength between coatings is guaranteed. (3) By matching the coating thickness of the two deposition processes, the structural density and uniformity of the coating interface area are improved, the corrosion resistance of the bipolar plate coating is enhanced, and the service life is extended.

[0070] The above description is only an optional embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for preparing a coating on a metal bipolar plate, characterized in that, The method for preparing the metal bipolar plate coating includes: Provide metal bipolar plates; The metal bipolar plate is subjected to magnetron sputtering ion deposition to obtain a metal bipolar plate with a magnetron sputtering ion deposition layer. The metal bipolar plate with the magnetron sputtering ion deposition layer is subjected to magnetron sputtering ion deposition and arc ion deposition in sequence to obtain a metal bipolar plate with an intermediate layer. Arc ion deposition is performed on the metal bipolar plate with the intermediate layer to obtain a metal bipolar plate with a coating structure.

2. The method for preparing the metal bipolar plate coating according to claim 1, characterized in that, The metal bipolar plate includes a cathode surface and an anode surface. The process of performing magnetron sputtering ion deposition on the metal bipolar plate to obtain a metal bipolar plate with a magnetron sputtering ion deposition layer includes: A first magnetron sputtering ion deposition is performed on the cathode surface to prepare a first magnetron sputtering ion deposition layer; simultaneously, a first magnetron sputtering ion deposition is performed on the anode surface to prepare a second magnetron sputtering ion deposition layer. A second magnetron sputtering ion deposition is performed on the surface of the first magnetron sputtering ion deposition layer away from the cathode surface to prepare a third magnetron sputtering ion deposition layer; simultaneously, a second magnetron sputtering ion deposition is performed on the surface of the second magnetron sputtering ion deposition layer away from the anode surface to prepare a fourth magnetron sputtering ion deposition layer, thereby obtaining a metal bipolar plate with magnetron sputtering ion deposition layers.

3. The method for preparing the metal bipolar plate coating according to claim 2, characterized in that, The first magnetron sputtering ion deposition layer is one or more of chromium, titanium, and niobium. The thickness of the first magnetron sputtering ion deposition layer and the second magnetron sputtering ion deposition layer is 10nm-500nm. The deposition power of the first magnetron sputtering ion deposition is 10W-5000W.

4. The method for preparing the metal bipolar plate coating according to claim 2, characterized in that, The second magnetron sputtering ion deposition layer is any one of Cr-NC, Ti-CN, and NbN. The thickness of the third and fourth magnetron sputtering ion deposition layers is 10nm-500nm, and the deposition power of the second magnetron sputtering ion deposition is 10W-5000W.

5. The method for preparing the metal bipolar plate coating according to claim 2, characterized in that, The process of sequentially performing magnetron sputtering ion deposition and arc ion deposition on the metal bipolar plate with the magnetron sputtering ion deposition layer to obtain a metal bipolar plate with an intermediate layer includes: A third magnetron sputtering ion deposition and a first arc ion deposition are sequentially performed on the surface of the third magnetron sputtering ion deposition layer away from the cathode surface to prepare a first intermediate layer. Simultaneously, a third magnetron sputtering ion deposition and a first arc ion deposition are sequentially performed on the surface of the fourth magnetron sputtering ion deposition layer away from the anode surface to prepare a second intermediate layer, thereby obtaining a metal bipolar plate with an intermediate layer.

6. The method for preparing the metal bipolar plate coating according to claim 5, characterized in that, The third magnetron sputtering ion deposition layer is any one of Cr-NC, Ti-CN, and NbN, the first arc ion deposition layer is C, and the intermediate layer is any one of Cr-NC / C, Ti-CN / C, and NbN / C.

7. The method for preparing the metal bipolar plate coating according to claim 5, characterized in that, The thickness of the intermediate layer is 10nm-100nm, the deposition power of the third magnetron sputtering ion deposition is 10W-5000W, and the deposition power of the first arc ion deposition is 10W-5000W.

8. The method for preparing the metal bipolar plate coating according to claim 5, characterized in that, The process of performing arc ion deposition on the metal bipolar plate with an intermediate layer to obtain a metal bipolar plate with a coating structure includes: A second arc ion deposition is performed on the surface of the first intermediate layer away from the cathode surface to prepare a first arc ion deposition layer. Simultaneously, a second arc ion deposition is performed on the surface of the second intermediate layer away from the anode surface to prepare a second arc ion deposition layer, resulting in a metal bipolar plate with a coating structure.

9. The method for preparing a metal bipolar plate coating according to claim 8, characterized in that, The second arc ion deposition layer is either C or N, the thickness of the first intermediate layer and the second intermediate layer is 10nm-500nm, and the deposition power of the second arc ion deposition is 10W-5000W.

10. A metal bipolar plate, characterized in that, The metal bipolar plate includes a metal bipolar plate coating prepared by the preparation method according to any one of claims 1-9.

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