Method for producing a coating, coating and fuel cell metal bipolar plate

Abstract

The application provides a coating preparation method, a coating and a fuel cell metal bipolar plate, and the coating preparation method comprises the following steps: in step S20, a substrate is sent into a cavity of a multi-target magnetron sputtering instrument, and a Ti bottom layer is prepared on the substrate by sputtering deposition; in step S30, a transition layer is prepared on the side, away from the substrate, of the Ti bottom layer by sputtering deposition, and the transition layer is a TiON layer; and in step S40, a top layer is prepared on the side, away from the Ti bottom layer, of the transition layer by sputtering deposition, and the top layer is a nitrogen-doped Magnéli phase titanium oxide layer. The technical scheme of the application can effectively solve the problem of poor corrosion resistance of the coating of the fuel cell metal bipolar plate in the prior art.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fuel cell metal bipolar plate, and particularly relates to a coating preparation method, a coating and a fuel cell metal bipolar plate. BACKGROUND

[0002] The bipolar plate plays a role in transporting reaction gas, supporting the stack, draining water and the like in a proton exchange membrane fuel cell, and is one of the core components of the stack. The bipolar plate made of metal material has excellent machining performance and low price, and is the key to replace the traditional graphite bipolar plate. However, the metal bipolar plate is not resistant to corrosion in the working condition environment of the fuel cell, and due to the passivation of the metal, the surface contact resistance of the coating is increased. The corrosion of metal ions causes irreversible damage to the membrane electrode of the stack. In order to solve the problem of corrosion and passivation of the metal bipolar plate and meet the application of the metal bipolar plate in the fuel cell, a coating layer needs to be prepared on the surface of the metal bipolar plate to meet the requirements of corrosion resistance and conductivity.

[0003] At present, a series of modified coatings have been applied to the bipolar plate of the fuel cell, for example, amorphous carbon, various metal nitrides and carbides have been widely studied and applied, and show excellent corrosion resistance and conductivity, so as to become potential bipolar plate coating materials. In addition, when the proton exchange membrane fuel cell is applied to the passenger car, the start-up, idling and other conditions may cause a potential as high as +1.6V (vs. SHE), and the change of the vehicle state causes the PEMFC stack potential to frequently fluctuate between 1.5-0.9V (vs. SHE). The noble metal gold has excellent performance, but the high cost hinders its application in the bipolar plate, and the carbon coating, metal nitride and carbide are easily dissolved or detached in the long-term high potential corrosion environment due to the limitation of the properties of the coating itself.

[0004] It is necessary to select a coating material that does not dissolve and detach in a long-term high potential corrosion environment for the development of the fuel cell metal bipolar plate coating material. SUMMARY

[0005] The main purpose of the present application is to provide a coating preparation method, a coating and a fuel cell metal bipolar plate, so as to solve the problem of poor corrosion resistance of the coating of the fuel cell metal bipolar plate in the prior art.

[0006] In order to achieve the above object, one aspect of the present application provides a coating preparation method, comprising: step S20, feeding a substrate into a multi-target magnetron sputtering instrument cavity, and preparing a Ti bottom layer on the substrate by sputtering deposition; step S30, preparing a transition layer on the side of the Ti bottom layer away from the substrate by sputtering deposition, the transition layer being a TiON layer; and step S40, preparing a top layer on the side of the transition layer away from the Ti bottom layer by sputtering deposition, the top layer being a nitrogen-doped Magnéli phase titanium oxide layer.

[0007] Further, step S40 comprises: step S41, controlling the nitrogen flow rate to be between 20-40sccm, the oxygen flow rate to be between 20-50sccm, the Ti target current to be between 5-10A, and the reaction temperature to be between 500-750℃ within a first preset time; step S42, depositing on the TiON layer for 60-150min; and step S43, after sputtering deposition, annealing at a temperature range of 550℃-750℃ for 1-2.5h to form a nitrogen-doped Magnéli phase titanium oxide layer.

[0008] Further, the first preset time is 300s.

[0009] Further, step S30 comprises: step S31, controlling the nitrogen flow rate to be 10-30sccm, the oxygen flow rate to be between 20-40sccm, and the Ti target current to be between 5-10A within a second preset time; and step S32, depositing on the Ti bottom layer for 30-60min.

[0010] Further, the second preset time is 300s.

[0011] Further, step S20 comprises: step S21, feeding the substrate into the multi-target magnetron sputtering instrument cavity; step S22, controlling the Ar flow rate to be 200sccm and the Ti target current to be between 5-10A within a third preset time; and step S23, depositing on the substrate for 30-60min.

[0012] Further, the third preset time is 600s.

[0013] Further, the coating preparation method further comprises: step S10, cleaning the substrate.

[0014] Further, the step S10 comprises: step S11, loading the substrate into a vacuum chamber, vacuumizing to 6*10-4Pa, then introducing Ar gas, the Ar gas flow rate is 200sccm, and the vacuum degree is maintained at 2-4Pa; step S12, ion bombardment on the substrate for 20-30min by using a medium frequency power supply; the step S20 comprises: step S21, sending the substrate into the cavity of a multi-target magnetron sputtering instrument; step S22, controlling the Ar gas flow rate to be constant within 600s, and controlling the Ti target current to be between 5-10A; step S23, depositing on the substrate for 30-60min; the step S30 comprises: step S31, controlling the Ti target current to be constant within 300s, controlling the nitrogen gas flow rate to be between 10-30sccm, and controlling the oxygen gas flow rate to be between 20-40sccm; step S32, depositing on the Ti bottom layer for 30-60min; the step S40 comprises: step S41, controlling the Ti target current to be constant within 300s, controlling the nitrogen gas flow rate to be between 20-40sccm, controlling the oxygen gas flow rate to be between 20-50sccm, and controlling the reaction temperature to be between 500-750℃; step S42, depositing on the TiON layer for 60-150min; step S43, after sputtering deposition, annealing treatment at a temperature range of 550-750℃ for 1-2.5h, to form a nitrogen-doped Magnéli phase titanium oxide layer.

[0015] Another aspect of the present application provides a coating layer, which is obtained by using the above-mentioned coating layer preparation method, and comprises: a Ti bottom layer; a transition layer located on one side of the Ti bottom layer, the transition layer being a TiON layer; and a top layer located on the side of the transition layer away from the Ti bottom layer, the top layer being a nitrogen-doped Magnéli phase titanium oxide layer.

[0016] Further, the thickness of the top layer is within 600nm.

[0017] Still another aspect of the present application provides a fuel cell metal bipolar plate, which comprises: a bipolar plate body; and a coating layer arranged on the surface of the bipolar plate body, the coating layer being the above-mentioned coating layer.

[0018] The coating layer preparation method of the present application successfully prepares a coating layer with a Ti bottom layer, a TiON transition layer and a nitrogen-doped Magnéli phase titanium oxide top layer by precisely controlling the sputtering deposition conditions. This coating layer structure not only enhances the bonding force between the substrate and the coating layer, but also improves the corrosion resistance, electrical conductivity and mechanical strength of the coating layer, thereby significantly improving the performance and service life of the fuel cell metal bipolar plate. In practical applications, this coating layer preparation method is simple, low in cost, and low in requirements for production equipment, and is suitable for large-scale production.

[0019] In addition to the objects, features and advantages described above, the present application has other objects, features and advantages. The present application will be further described in detail below with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0020] The accompanying drawings, which form a part of this specification, are included to provide a further understanding of the application, illustrate preferred embodiments of the application and assist in explaining the application. In the drawings:

[0021] Figure 1 A schematic view of a structure of an embodiment of a coating according to the application on a substrate is shown.

[0022] Wherein the above mentioned drawings include the following reference signs:

[0023] 1. Substrate; 10. Ti underlayer; 20. Transition layer; 30. Top layer. DETAILED DESCRIPTION

[0024] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0025] In order to make the personnel in the technical field better understand the present application scheme, the technical scheme in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by the person skilled in the art without creative labor should belong to the protection scope of the present application.

[0026] It should be noted that the terms "first", "second", and the like in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and do not have to be used to describe a specific order or sequence. It should be understood that the terms thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0027] It should be noted that the terms used herein are only for the purpose of describing specific embodiments, and are not intended to limit the exemplary embodiments according to the present application. As used herein, the singular form is intended to include the plural form unless the context clearly indicates otherwise, and it should also be understood that when the terms "comprise" and / or "include" are used in the specification, they indicate the presence of a feature, step, operation, device, component and / or combination thereof.

[0028] As Figure 1 shown in the present application, the preparation method of the coating includes: step S20: sending the substrate 1 into the multi-target magnetron sputtering instrument cavity, and preparing the Ti bottom layer 10 on the substrate 1 by sputtering deposition; step S30: preparing the transition layer 20 on the side of the Ti bottom layer 10 away from the substrate 1 by sputtering deposition, the transition layer 20 being a TiON layer; step S40: preparing the top layer 30 on the side of the transition layer 20 away from the Ti bottom layer 10 by sputtering deposition, the top layer 30 being a nitrogen-doped Magnéli phase titanium oxide layer. On the one hand, the coating prepared by magnetron sputtering grows in columnar crystals, which often produces deep grain boundaries. The use of the transition layer TiON coating as a buffer layer further corrodes and blocks, so that it remains in a stable state in a long-term high-potential corrosion environment. On the other hand, the introduction of the nitrogen-doped Magnéli phase titanium oxide layer significantly enhances the corrosion resistance of the coating, which is suitable for the manufacture of fuel cell metal bipolar plates, especially in a highly corrosive environment, which can effectively protect the bipolar plate and prolong its service life.

[0029] It should be noted that the conduction mechanism of the Magnéli phase titanium oxide coating is that a crystal shear plane is formed in the TiO2 lattice. The oxygen-deficient state of the crystal shear plane leads to an increase in the overlap of electron clouds between titanium atoms, thereby enhancing the mobility of electrons and improving the electrical conductivity, thereby providing a channel for electron transition, so that this structure has excellent electrical conductivity. At the same time, the crystal shear plane is surrounded by the TiO2 lattice and is not easily corroded by acidic ions, so the coating has good corrosion resistance.

[0030] However, in the prior art, Magnéli phase titanium oxide has problems of complex preparation, high cost and high requirements for equipment in large-scale preparation. In order to further solve the above problems, in the present application, step S40 comprises: step S41: controlling the nitrogen flow to be between 20-40sccm, controlling the oxygen flow to be between 20-50sccm, controlling the Ti target current to be between 5-10A, and controlling the reaction temperature to be between 500-750℃ within a first preset time; step S42: depositing on the TiON layer for 60-150min; step S43: after sputtering deposition, annealing treatment at a temperature range of 550℃-750℃ for 1-2.5h to form a nitrogen-doped Magnéli phase titanium oxide layer. Specifically, the inventors propose that the formation of the crystal shear plane is the key to large-scale preparation of Magnéli phase titanium oxide coating. The technical solution of the present application precisely controls the O2 flow and Ti target current, and gives Ti more energy through high-temperature deposition; when there is nitrogen doping, the highly dispersed nitrogen atoms replace the originally high-energy Ti atoms or ions, and this replacement of atoms in the crystal lattice introduces additional charges, which balances the charge imbalance around the nitrogen atoms through the charge compensation mechanism, and finally forms oxygen vacancies, inducing the formation of crystal shear planes. At the same time, the later annealing makes the compensation mechanism more balanced, so that the structure reaches balance, and finally forms pure phase or multi-phase Magnéli phase titanium oxide. The above preparation method makes the Magnéli phase titanium oxide simple to prepare, low in cost and low in requirements for equipment in large-scale preparation.

[0031] Further, the first preset time is 300s. Setting the first preset time to 300s can ensure the deposition quality of the TiON layer, and at the same time control the deposition time to avoid the increase of energy consumption and the decline of production efficiency caused by too long deposition time, which is suitable for large-scale production environment, can effectively improve the production efficiency and reduce the production cost.

[0032] Further, step S30 comprises: step S31, linearly increasing the nitrogen flow to 10-30sccm and linearly increasing the oxygen flow to 20-40sccm within a second preset time, and controlling the Ti target current to be between 5-10A; step S32, depositing on the Ti bottom layer 10 for 30-60min. By controlling the nitrogen and oxygen flow, a stable TiON transition layer can be formed on the Ti bottom layer, which acts as a buffer layer to further block corrosion, so that it remains in a stable state in a long-term high-potential corrosion environment.

[0033] Further, the second preset time is 300s. Setting the second preset time to 300s can ensure that the deposition process of the TiON transition layer is completed within a controllable time, avoid the performance decline caused by too thick or too thin transition layer, and is suitable for precision manufacturing process, which can improve the accuracy and consistency of coating preparation.

[0034] Further, step S20 comprises: step S21, sending the substrate 1 into the multi-target magnetron sputtering instrument cavity; step S22, controlling the Ar gas flow rate 200sccm within the third preset time, and controlling the Ti target current to linearly increase to 5-10A; step S23, depositing on the substrate 1 for 30-60min. By controlling the Ar gas flow rate and the Ti target current, a dense Ti bottom layer can be formed on the substrate, providing a good foundation for subsequent coating preparation, suitable for coating preparation requiring high bonding force, especially in the surface treatment of bipolar plates, which can significantly improve the bonding strength of the coating and the substrate, and reduce the risk of coating falling off.

[0035] Further, the third preset time is 600s. By setting the third preset time to 600s, it can be ensured that the deposition process of the Ti bottom layer is completed within the best time, forming a Ti bottom layer that is neither too thick nor too thin, suitable for coating preparation that pursues optimal performance, especially in the manufacturing of fuel cell bipolar plates with strict requirements for coating thickness, which can provide precise thickness control and ensure the optimization of coating performance.

[0036] Further, the coating preparation method further comprises: step S10, cleaning the substrate 1. Cleaning the substrate is a key step before coating preparation, which can remove impurities and oxides on the surface of the substrate, improve the bonding force of the coating and the substrate, and is suitable for various coating preparation processes requiring high surface cleanliness, especially in the manufacturing of fuel cell metal bipolar plates, which can significantly improve the adhesion and corrosion resistance of the coating.

[0037] Further, step S10 comprises: step S11, loading the substrate 1 into the vacuum chamber, and after vacuumizing to 6x10-4Pa, introducing Ar gas with a flow rate of 200sccm, and maintaining the vacuum degree at 2-4Pa; step S12, ion bombardment of the substrate 1 for 20-30min by using a medium frequency power source. Through ion bombardment, the surface of the substrate can be further cleaned, the activity of the substrate can be improved, and atomic diffusion and bonding in the subsequent deposition process can be promoted, which is suitable for coating preparation requiring high surface activity, especially in the manufacturing of fuel cell metal bipolar plates, which can significantly improve the bonding force and corrosion resistance of the coating, and provide protection for the efficient operation of fuel cells.

[0038] Specifically, in the present application, the cleaning step is specifically: first, the polished substrate is sent into an ultrasonic cleaner, and is cleaned in anhydrous alcohol and acetone respectively by using 15kHz ultrasonic waves for 20-30min; then, ion cleaning is performed; the above-mentioned ion cleaning is: the substrate is loaded into a vacuum chamber, vacuumized to 6x10-4Pa, then Ar gas is introduced, the vacuum degree is maintained at 2-4Pa, and the substrate is ion bombarded for 30min by using a medium frequency power source.

[0039] The preparation method of the specific coating of the present application is described in detail below:

[0040] Step S11: Put the substrate 1 into the vacuum chamber, vacuumize to 6x10-4Pa, then introduce Ar gas, Ar gas flow rate 200sccm, maintain the vacuum degree at 2-4Pa;

[0041] Step S12: Use the intermediate frequency power source to perform ion bombardment on the substrate 1 for 20-30min;

[0042] Step S21: Put the substrate 1 into the multi-target magnetron sputtering instrument cavity;

[0043] Step S22: Control the Ar gas flow rate unchanged within 600s, and control the Ti target current linearly increased to 5-10A;

[0044] Step S23: Deposit on the substrate 1 for 30-60min;

[0045] Step S31: Control the Ti target current unchanged within 300s, linearly increase the nitrogen gas flow rate to 10-30sccm, and linearly increase the oxygen gas flow rate to 20-40sccm;

[0046] Step S32: Deposit on the Ti bottom layer 10 for 30-60min;

[0047] Step S41: Control the Ti target current unchanged within 300s, control the nitrogen gas flow rate to 20-40sccm, control the oxygen gas flow rate to 20-50sccm, and control the reaction temperature to 500-750℃;

[0048] Step S42: Deposit on the TiON layer for 60-150min;

[0049] Step S43: After sputtering deposition, annealing treatment at a temperature range of 550℃-750℃ for 1-2.5h, to form a nitrogen-doped Magnéli phase titanium oxide layer.

[0050] In the present application, the specific implementation details of the coating preparation method are described in detail to prove the feasibility and superiority of the technical solution. Below, according to the above parameter range, the coating preparation method will be further analyzed and extended described to provide more examples, and show the changes of coating structure and performance under different conditions.

[0051] Example 1

[0052] In this embodiment, the coating preparation method follows the following steps: first, the substrate is sent into the multi-target magnetron sputtering instrument cavity, the preparation conditions of the Ti bottom layer are as follows: the Ar gas flow is controlled at 200 sccm, the Ti target current is linearly increased to 10 A, and the deposition time is 30 min. Next, the preparation conditions of the transition layer TiON are as follows: within 5 minutes, the nitrogen flow is linearly increased to 20 sccm, the oxygen flow is linearly increased to 30 sccm, the Ti target current remains unchanged, and the deposition time is 60 min. Finally, the preparation of the nitrogen-doped Magnéli phase titanium oxide top layer requires more detailed temperature and gas control, the nitrogen flow remains unchanged, the oxygen flow is 35 sccm, the Ti target current remains unchanged, the reaction temperature is set to 750 DEG C, and the deposition time is 120 min. After the sputtering deposition is completed, the annealing treatment is performed at 750 DEG C for 100 min for 1-2.5 h.

[0053] It is detected that the surface contact resistance of the obtained nitrogen-doped Magnéli phase titanium oxide coating before corrosion is 4.37 mΩ·cm 2 , the surface contact resistance after corrosion for 10 h of constant potential polarization at +1.6 V (vs. SHE) is increased to 6.28 mΩ·cm 2 , and the constant potential polarization curve remains stable.

[0054] Example 2

[0055] In this embodiment, the coating preparation method follows the following steps: first, the substrate is sent into the multi-target magnetron sputtering instrument cavity, the preparation conditions of the Ti bottom layer are as follows: the Ar gas flow is controlled at 200 sccm, the Ti target current is linearly increased to 8 A, and the deposition time is 30 min. Next, the preparation conditions of the transition layer TiON are as follows: within 5 minutes, the nitrogen flow is linearly increased to 30 sccm, the oxygen flow is linearly increased to 20 sccm, the Ti target current remains unchanged, and the deposition time is 60 min. Finally, the preparation of the nitrogen-doped Magnéli phase titanium oxide top layer requires more detailed temperature and gas control, the nitrogen flow remains unchanged, the oxygen flow is 45 sccm, the Ti target current remains unchanged, the reaction temperature is set to 700 DEG C, and the deposition time is 120 min. After the sputtering deposition is completed, the annealing treatment is performed at 700 DEG C for 90 min for 1-2.5 h.

[0056] It is detected that the surface contact resistance of the obtained nitrogen-doped Magnéli phase titanium oxide coating before corrosion is 3.52 mΩ·cm 2 , the surface contact resistance after corrosion for 10 h of constant potential polarization at +1.6 V (vs. SHE) is increased to 7.98 mΩ·cm 2 , and the constant potential polarization curve remains stable.

[0057] Example 3

[0058] In this embodiment, the coating preparation method follows the following steps: first, the substrate is sent into the multi-target magnetron sputtering instrument cavity, the preparation conditions of the Ti bottom layer are as follows: the Ar gas flow is controlled at 200 sccm, the Ti target current is linearly increased to 10 A, and the deposition time is 40 min. Next, the preparation conditions of the transition layer TiON are as follows: within 5 minutes, the nitrogen flow is linearly increased to 20 sccm, the oxygen flow is linearly increased to 20 sccm, the Ti target current remains unchanged, and the deposition time is 60 min. Finally, the preparation of the nitrogen-doped Magnéli phase titanium oxide top layer requires more detailed temperature and gas control, the nitrogen and oxygen flows remain unchanged, the Ti target current remains unchanged, the reaction temperature is set to 750°C, and the deposition time is 120 min. After the sputtering deposition is completed, the annealing treatment is performed at 750°C for 100 min for 1-2.5 h.

[0059] It is detected that the surface contact resistance of the obtained nitrogen-doped Magnéli phase titanium oxide coating before corrosion is 4.25 mΩ·cm 2 , the surface contact resistance after corrosion for 10 h of constant potential polarization at +1.6 V (vs. SHE) is increased to 6.84 mΩ·cm 2 , and the constant potential polarization curve remains stable.

[0060] Example 4

[0061] In this embodiment, the coating preparation method follows the following steps: first, the substrate is sent into the multi-target magnetron sputtering instrument cavity, the preparation conditions of the Ti bottom layer are as follows: the Ar gas flow is controlled at 200 sccm, the Ti target current is linearly increased to 5 A, and the deposition time is 50 min. Next, the preparation conditions of the transition layer TiON are as follows: within 5 minutes, the nitrogen flow is linearly increased to 30 sccm, the oxygen flow is linearly increased to 40 sccm, the Ti target current remains unchanged, and the deposition time is 60 min. Finally, the preparation of the nitrogen-doped Magnéli phase titanium oxide top layer requires more detailed temperature and gas control, the nitrogen flow is linearly increased to 40 sccm, the oxygen flow is linearly increased to 50 sccm, the Ti target current remains unchanged, the reaction temperature is set to 500°C, and the deposition time is 130 min. After the sputtering deposition is completed, the annealing treatment is performed at 500°C for 110 min for 1-2.5 h.

[0062] It is detected that the surface contact resistance of the obtained nitrogen-doped Magnéli phase titanium oxide coating before corrosion is 3.45 mΩ·cm 2 , the surface contact resistance after corrosion for 10 h of constant potential polarization at +1.6 V (vs. SHE) is increased to 9.48 mΩ·cm 2 , and the constant potential polarization curve remains stable.

[0063] Example 5

[0064] In this embodiment, the coating preparation method follows the following steps: first, the substrate is sent into the multi-target magnetron sputtering instrument cavity, the preparation conditions of the Ti bottom layer are as follows: the Ar gas flow is controlled at 200 sccm, the Ti target current is linearly increased to 7 A, and the deposition time is 60 min. Next, the preparation conditions of the transition layer TiON are as follows: within 5 minutes, the nitrogen flow is linearly increased to 20 sccm, the oxygen flow is linearly increased to 30 sccm, the Ti target current remains unchanged, and the deposition time is 60 min. Finally, the preparation of the nitrogen-doped Magnéli phase titanium oxide top layer requires more detailed temperature and gas control, the nitrogen flow is 30 sccm, the oxygen flow is 40 sccm, the Ti target current remains unchanged, the reaction temperature is set to 600 DEG C, and the deposition time is 140 min. After the sputtering deposition is completed, the annealing treatment is performed at 600 DEG C for 100 min for 1-2.5 h.

[0065] It is detected that the surface contact resistance of the obtained nitrogen-doped Magnéli phase titanium oxide coating before corrosion is 2.89 mΩ·cm 2 , the surface contact resistance after corrosion for 10 h under +1.6 V (vs. SHE) constant potential polarization is increased to 8.56 mΩ·cm 2 , and the constant potential polarization curve remains stable.

[0066] As can be seen from the above embodiment, the coating prepared by the coating preparation method of the application has a stable state of constant potential polarization at a high potential, and the surface contact resistance is <10 mΩ·cm 2 after corrosion for 10 h.

[0067] Comparative Example 1

[0068] In this embodiment, the coating preparation method follows the following steps: first, the substrate is sent into the multi-target magnetron sputtering instrument cavity, the preparation conditions of the Ti bottom layer are as follows: the Ar gas flow is controlled at 200 sccm, the Ti target current is linearly increased to 10 A, and the deposition time is 60 min. Next, the preparation conditions of the transition layer TiON are as follows: within 5 minutes, the nitrogen flow is linearly increased to 20 sccm, the oxygen flow is linearly increased to 10 sccm, the Ti target current remains unchanged, and the deposition time is 60 min. Finally, the preparation of the nitrogen-doped Magnéli phase titanium oxide top layer requires more detailed temperature and gas control, the nitrogen flow and the oxygen flow remain unchanged, the Ti target current remains unchanged, the reaction temperature is set to 750 DEG C, and the deposition time is 140 min. After the sputtering deposition is completed, the annealing treatment is performed at 750 DEG C for 100 min for 1-2.5 h.

[0069] It is detected that the surface contact resistance of the obtained nitrogen-doped Magnéli phase titanium oxide coating before corrosion is 4.83 mΩ·cm2 The surface contact resistance of the obtained Magnéli phase titanium oxide coating before corrosion was 5.83 mΩ·cm 2 .

[0070] Comparative Example 2

[0071] In this example, the coating preparation method followed the following steps: first, the substrate was sent into the multi-target magnetron sputtering instrument cavity, the preparation conditions of the Ti bottom layer were as follows: the Ar gas flow was controlled at 200 sccm, the Ti target current was linearly increased to 7 A, and the deposition time was 60 min. Next, the preparation conditions of the transition layer TiON were as follows: within 5 minutes, the nitrogen flow was linearly increased to 10 sccm, the oxygen flow was linearly increased to 30 sccm, the Ti target current remained unchanged, and the deposition time was 60 min. Finally, the preparation of the nitrogen-doped Magnéli phase titanium oxide top layer required more detailed temperature and gas control, the nitrogen flow remained unchanged, the oxygen flow was increased to 40 sccm, the Ti target current remained unchanged, the reaction temperature was set to 600°C, and the deposition time was 140 min. After the sputtering deposition was completed, annealing treatment was performed for 1-2.5 h at 600°C for 100 min.

[0072] It was detected that the surface contact resistance of the obtained nitrogen-doped Magnéli phase titanium oxide coating before corrosion was 5.83 mΩ·cm 2 , and the surface contact resistance increased to 26.28 mΩ·cm after 10 h of corrosion by +1.6 V (vs. SHE) constant potential polarization 2 .

[0073] Comparative Example 3

[0074] In this example, the coating preparation method followed the following steps: first, the substrate was sent into the multi-target magnetron sputtering instrument cavity, the preparation conditions of the Ti bottom layer were as follows: the Ar gas flow was controlled at 200 sccm, the Ti target current was linearly increased to 4 A, and the deposition time was 60 min. Next, the preparation conditions of the transition layer TiON were as follows: within 5 minutes, the nitrogen flow was linearly increased to 10 sccm, the oxygen flow was linearly increased to 30 sccm, the Ti target current remained unchanged, and the deposition time was 60 min. Finally, the preparation of the nitrogen-doped Magnéli phase titanium oxide top layer required more detailed temperature and gas control, the nitrogen flow was increased to 30 sccm, the oxygen flow was increased to 40 sccm, the Ti target current remained unchanged, the reaction temperature was set to 600°C, and the deposition time was 140 min. After the sputtering deposition was completed, annealing treatment was performed for 1-2.5 h at 600°C for 100 min.

[0075] It was detected that the surface contact resistance of the obtained nitrogen-doped Magnéli phase titanium oxide coating before corrosion was 22.45 mΩ·cm2 The surface contact resistance of the obtained Magnéli phase titanium oxide coating before corrosion was 159.03 Ω·cm 2 .

[0076] Comparative Example 4

[0077] In this example, the coating preparation method follows the following steps: first, the substrate is sent into the multi-target magnetron sputtering instrument cavity, the preparation conditions of the Ti bottom layer are as follows: the Ar gas flow is controlled at 200 sccm, the Ti target current is linearly increased to 7 A, and the deposition time is 60 min. Next, the preparation conditions of the transition layer TiON are as follows: within 5 minutes, the nitrogen flow is linearly increased to 10 sccm, the oxygen flow is linearly increased to 30 sccm, the Ti target current remains unchanged, and the deposition time is 60 min. Finally, the preparation of the nitrogen-doped Magnéli phase titanium oxide top layer requires more detailed temperature and gas control, the nitrogen flow is increased to 30 sccm, the oxygen flow is increased to 40 sccm, the Ti target current remains unchanged, the reaction temperature is set to 450°C, and the deposition time is 140 min. After the sputtering deposition is completed, annealing treatment is performed at 450°C for 100 min for 1-2.5 h.

[0078] It is detected that the surface contact resistance of the obtained nitrogen-doped Magnéli phase titanium oxide coating before corrosion is 159.03 Ω·cm 2 , the surface contact resistance after 10 h corrosion of constant potential polarization of +1.6 V (vs. SHE) is increased to 267.88 mΩ·cm 2 .

[0079] Comparative Example 5

[0080] In this example, the coating preparation method follows the following steps: first, the substrate is sent into the multi-target magnetron sputtering instrument cavity, the preparation conditions of the Ti bottom layer are as follows: the Ar gas flow is controlled at 200 sccm, the Ti target current is linearly increased to 7 A, and the deposition time is 60 min. Next, the preparation conditions of the transition layer TiON are as follows: within 5 minutes, the nitrogen flow is linearly increased to 10 sccm, the oxygen flow is linearly increased to 30 sccm, the Ti target current remains unchanged, and the deposition time is 60 min. Finally, the preparation of the nitrogen-doped Magnéli phase titanium oxide top layer requires more detailed temperature and gas control, the nitrogen flow is increased to 30 sccm, the oxygen flow is increased to 40 sccm, the Ti target current remains unchanged, the reaction temperature is set to 600°C, and the deposition time is 140 min. After the sputtering deposition is completed, no annealing treatment is performed.

[0081] It is detected that the surface contact resistance of the obtained nitrogen-doped titanium oxide coating before corrosion is 139.05 mΩ·cm 2After being constant potential polarized for 10 h at +1.6 V (vs. SHE), the surface contact resistance of the coating increased to 247.81 mΩ·cm 2 .

[0082] In addition, the application also provides a coating, the coating is obtained by the above preparation method, the coating according to the embodiment of the application comprises: a Ti bottom layer 10, a transition layer 20 and a top layer 30. The transition layer 20 is located on one side of the Ti bottom layer 10, and the transition layer 20 is a TiON layer; the top layer 30 is located on the side of the transition layer 20 away from the Ti bottom layer 10, and the top layer 30 is a nitrogen-doped Magnéli phase titanium oxide layer. The coating has the advantages of good electrical conductivity and good corrosion resistance.

[0083] Further, the thickness of the top layer 30 is within 600 nm. Controlling the thickness of the top layer within 600 nm can ensure that the coating has good electrical conductivity, avoid high resistance caused by too thick coating, and be suitable for the manufacture of fuel cell bipolar plates requiring high electrical conductivity, especially in fuel cell applications pursuing high power output, which can effectively reduce the internal resistance of the battery, improve the power density of the battery, and exhibit excellent stability and reliability in harsh operating environments, providing a solid foundation for the commercial application of fuel cell technology.

[0084] The application also provides a fuel cell metal bipolar plate, and the embodiment of the fuel cell metal bipolar plate according to the application comprises: a bipolar plate body and a coating arranged on the bipolar plate body. Such a bipolar plate, by adopting a coating with a layered structure, not only improves corrosion resistance and electrical conductivity, but also enhances mechanical strength, is suitable for the manufacture of high-performance fuel cells, especially in extreme operating conditions such as high temperature, high humidity and high corrosive environment, can effectively protect the bipolar plate, prolong its service life, and reduce maintenance costs, providing reliable technical support for the widespread application of fuel cells in the fields of automobiles, power stations and the like.

[0085] The relative arrangement of parts and steps, numerical expressions, and numerical values set forth in the various embodiments herein are not meant to limit the scope of the present application unless otherwise specifically stated. It is also to be understood that the use of relational terms such as, but not limited to, first, second, top, bottom, upper, lower, front, rear, left, right, over, under, above, below, up, down, and the like are used for clarity in only the view of the figures presented and that these relative terms are not intended to denote a fixed position in time. Techniques, methods, and apparatus known to those of ordinary skill are not discussed in detail because such techniques, methods, and apparatus are considered to be part of the existing art. In all examples shown and discussed herein, any specific values are to be interpreted as merely illustrative and not as a limitation. Thus, other examples of exemplary embodiments can have different values. It is noted that like numbers and letters on the figures identify like parts throughout the several views, and thus, once an item is defined in one view, it is not necessary to discuss it further in subsequent views.

[0086] For purposes of the description hereinafter, spatial terms, such as "above", "below", "upper", "lower", and the like, can be used with reference to the illustrated orientation of one device or component relative to another device or component as shown in the figures. It will be understood that the spatial terms are intended to encompass different orientations of the device or component in use or operation, in addition to the orientation depicted in the figures. For example, if a device or component is inverted, or rotated by 90 degrees, or in other ways, the spatial terms will need to be interpreted accordingly. Accordingly, the exemplary term "above" can encompass both an orientation of above and below. The devices can be otherwise oriented (rotated 90 degrees or at other orientations) and the spatial terms will be interpreted accordingly.

[0087] In the description of the present application, it is to be understood that the orientation terms such as "front", "back", "upper", "lower", "left", "right", "lateral", "vertical", "horizontal", and "top", "bottom" and the like are made only with reference to the positions of the components as shown in the drawings, and are made merely by way of illustrative convenience with respect to the description of the application and simplified description, and do not indicate or imply that the devices or elements referred to must have a particular orientation or be constructed and operated in a particular orientation, and therefore should not be construed as limiting the scope of the present application; the orientation terms "inner", "outer" refer to the inner and outer relative to the outline of each component.

[0088] The preferred embodiments of the present application have been described above with the specific reference to the drawings. The application is not limited to the embodiments described, but can be variously changed and modified by those skilled in the art without departing from the spirit and scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the present application.

Claims

1. A method for the production of a coating, characterized in that Comprising: Step S20: sending the substrate (1) into the multi-target magnetron sputtering instrument cavity, preparing a Ti bottom layer (10) on the substrate (1) by sputtering deposition, wherein the step S20 comprises: Step S21: sending the substrate (1) into the multi-target magnetron sputtering instrument cavity; Step S22: controlling the Ar gas flow to be 200sccm within a third preset time, and controlling the Ti target current to linearly increase to between 5-10A; Step S23: depositing on the substrate (1) for 30-60min; Step S30: preparing a transition layer (20) on the side of the Ti bottom layer (10) away from the substrate (1) by sputtering deposition, the transition layer (20) being a TiON layer, wherein the step S30 comprises: Step S31: linearly increasing the nitrogen flow to between 10-30sccm and linearly increasing the oxygen flow to between 20-40sccm within a second preset time, and controlling the Ti target current to be between 5-10A; Step S32: depositing on the Ti bottom layer (10) for 30-60min; Step S40: preparing a top layer (30) on the side of the transition layer (20) away from the Ti bottom layer (10) by sputtering deposition, the top layer (30) being a nitrogen-doped Magnéli phase titanium oxide layer, wherein, The step S40 comprises: Step S41: controlling the nitrogen flow to be between 20-40sccm, controlling the oxygen flow to be between 20-50sccm, controlling the Ti target current to be between 5-10A, and controlling the reaction temperature to be between 500-750℃ within a first preset time; Step S42: depositing on the TiON layer for 60-150min; Step S43: after sputtering deposition, annealing treatment at a temperature range of 550℃-750℃ for 1-2.5h to form the nitrogen-doped Magnéli phase titanium oxide layer.

2. The method of claim 1, wherein the coating is prepared by a method comprising: The first preset time is 300s.

3. The method of claim 1, wherein the coating is prepared by a method comprising: The second preset time is 300s.

4. The method of claim 1, wherein the coating is prepared by a method comprising: The third preset time is 600s.

5. The method of claim 1, wherein the coating is prepared by a method comprising: The preparation method of the coating further comprises: Step S10: cleaning the substrate (1).

6. The method of claim 5, wherein the coating is prepared by a method comprising: The step S10 comprises: Step S11: loading the substrate (1) into a vacuum chamber, evacuating to 6×10-4Pa, then introducing Ar gas, the Ar gas flow being 200sccm, and maintaining the vacuum degree to be between 2-4Pa; Step S12: ion bombardment of the substrate (1) for 20-30min by a medium frequency power supply; The step S20 comprises: Step S21: sending the substrate (1) into the multi-target magnetron sputtering instrument cavity; Step S22: controlling the Ar gas flow to be constant within 600s, and linearly increasing the Ti target current to between 5-10A; Step S23: depositing on the substrate (1) for 30-60min; The step S30 comprises: Step S31: controlling the Ti target current to be constant within 300s, linearly increasing the nitrogen flow to between 10-30sccm, and linearly increasing the oxygen flow to between 20-40sccm; Step S32: depositing on the Ti bottom layer (10) for 30-60min; Step S32: depositing on the Ti underlayer (10) for 30-60 min; the step S40 comprises: Step S41: controlling the Ti target current to be constant within 300 s, controlling the nitrogen flow rate to be between 20-40 sccm, controlling the oxygen flow rate to be between 20-50 sccm, and controlling the reaction temperature to be between 500-750℃; Step S42: depositing on the TiON layer for 60-150 min; Step S43: after sputtering deposition, annealing treatment at a temperature range of 550℃-750℃ for 1-2.5 h to form the nitrogen-doped Magnéli phase titanium oxide layer.

7. A coating characterized in that, The coating layer is obtained by the preparation method of any one of claims 1-6, and the coating layer comprises: a Ti underlayer (10); a transition layer (20) located on one side of the Ti underlayer (10), wherein the transition layer (20) is a TiON layer; a top layer (30) located on the side of the transition layer (20) away from the Ti underlayer (10), wherein the top layer (30) is a nitrogen-doped Magnéli phase titanium oxide layer.

8. The coating of claim 7, wherein, The thickness of the top layer (30) is within 600 nm.

9. A fuel cell metal bipolar plate, comprising: a bipolar plate body; a coating layer arranged on the surface of the bipolar plate body, characterized in that the coating layer is prepared by the preparation method of any one of claims 1-6.

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