A four-chamber deposition system for metal carbide coatings on fuel cell plates

Abstract

A four-chamber deposition system for a fuel cell plate metal carbide coating mainly includes: a film feeding chamber, a transition layer deposition chamber, a metal carbide layer deposition chamber and a film output chamber in sequence; the inlet and outlet of each chamber are provided with chamber valves, and the chamber valves separate the chambers on both sides from each other; a sample transmission device passes through the bottom of each chamber to form a closed loop; the sample is mounted on the sample transmission device, and the sample is carried through each chamber from left to right in sequence. The present invention adopts a combination of an unbalanced magnetic field and a balanced magnetic field, optimizes the matching of the magnetic field mode, the power supply system and the target-substrate distance, and improves the bonding performance and stability performance of the metal carbide coating; adopts a continuous small-scale deposition device, and introduces automated equipment such as a manipulator to achieve rapid deposition of the metal carbide coating, which can reduce the coating preparation cost.

Description

Technical Field

[0001] The invention belongs to the technical field of fuel cells and relates to a four-chamber deposition system for a metal carbide coating on a fuel cell pole plate. Background Art

[0002] With the continuous development of society, the limited reserves of fossil energy such as coal and oil and the adverse impact on the ecological environment, clean and renewable energy have been widely used and received great attention. Among them, fuel cells, as a power generation device that directly generates electricity through electrochemical reactions, have attracted the attention of many institutions and personnel. Proton exchange membrane fuel cells (PEMFC) using hydrogen as fuel have been widely used, and the application range has included automobiles, drones, fixed power stations, etc. In proton exchange membrane fuel cells, the plates are responsible for distributing gas, transferring heat, and supporting membrane electrodes. In addition, during the operation of the fuel cell, the operating temperature of the plates can reach 65-85°C, and at the same time they are in an acidic solution environment with pH=3, and there is a certain potential, ranging from 0.6 to 1.6V. For metal plates that have not been treated in any way, continuous operation in this environment will produce severe electrochemical corrosion, which will cause the attenuation of fuel cell performance and the reduction of life. By performing corresponding surface modification on the plates, such as deposition coating, the conductivity and corrosion resistance of the fuel cell plates can be further improved. In a fuel cell stack, dozens of plates and membrane electrode stacks are assembled together, which places higher demands on the consistency and uniformity of the plates in order to meet the fuel cell's lifespan of thousands of hours.

[0003] At present, there are four main types of coatings for surface treatment and modification of fuel cell metal plates, namely precious metal coatings, graphite coatings, conductive polymer coatings and metal ceramic coatings. Although both precious metal coatings and graphite coatings have good chemical stability and good conductivity, precious metal coatings have high material costs due to material selection, and graphite coatings have high time costs due to their slow deposition rate. Therefore, excessively high material and time costs are not conducive to large-scale production. The chemical properties of conductive polymer coatings are not very stable, and the mechanical properties and bonding properties of the material itself limit its wide application.

[0004] Metal ceramic coatings, especially metal carbide coatings, have extremely excellent electrical conductivity and corrosion resistance. At the same time, they have the characteristics of fast deposition rate and low production cost, which makes them widely used in the actual production process. In metal carbide coatings, carbon atoms and metal atoms form crystals through strong chemical bonds, thus having high electrical conductivity. However, due to the influence of deposition environment and deposition process, there will still be a small amount of metal elements in the metal carbide coating, and these metal elements will escape during the service of the plate, causing the coating performance to decline and the life to be shortened.

[0005] At present, most of the preparation of metal carbide coatings is focused on the research of single equipment, but the production efficiency of single equipment is far lower than that of continuous equipment, and the adjustable parameters are limited, which is not conducive to mass production. At the same time, the conductivity of metal carbide coatings is greatly improved compared with graphite coatings and precious metal coatings. Therefore, the formation of metal carbide crystals can be effectively promoted by etching the coating during the deposition process, so that the conductive particles are exposed on the surface of the coating, thereby further improving the conductivity and corrosion resistance of the coating. Summary of the invention

[0006] The purpose of the present invention is to provide a four-chamber deposition system for a fuel cell polar plate metal carbide coating to overcome the above-mentioned problems existing in the prior art.

[0007] A four-chamber deposition system for a fuel cell plate metal carbide coating, characterized in that it mainly comprises: a film input chamber, a transition layer deposition chamber, a metal carbide layer deposition chamber and a film output chamber in sequence; the inlet and outlet of each chamber are provided with chamber valves, and the chamber valves separate the chambers on both sides from each other; a sample transmission device passes through the bottom of each chamber to form a closed loop; the sample is mounted on the sample transmission device, and the sample is carried through each chamber in sequence from left to right.

[0008] Furthermore, a four-chamber deposition system for a fuel cell plate metal carbide coating of the present invention is also equipped with independent vacuum systems, power supply systems and gas circuit systems in the film input chamber, transition layer deposition chamber, metal carbide layer deposition chamber and film output chamber, respectively.

[0009] The sample rack can hang 2 to 20 fuel cell plates, and a mechanical arm or other similar automated devices are used to complete the loading and unloading process of the fuel cell plates.

[0010] The film feeding chamber is used for evacuation and sample cleaning. The cleaning methods include radio frequency self-bias cleaning, pulse bias cleaning and ion source cleaning symmetrically arranged on both sides of the cavity. At the same time, hydrogen is introduced into the cavity to etch the oxide on the sample surface.

[0011] Furthermore, the hydrogen flow rate used in the etching process is 5 to 500 sccm.

[0012] A certain number of heating devices are symmetrically and evenly arranged on both side walls of the transition layer deposition chamber and the metal carbide layer deposition chamber for heating the sample; the deposition temperature of the transition layer deposition chamber is 0-700°C, and the deposition temperature of the metal carbide layer deposition chamber is 0-1000°C.

[0013] Furthermore, cathode magnetic fields are provided on both side walls of the transition layer deposition chamber and the metal carbide layer deposition chamber, respectively, and are arranged at intervals from the heating device; the cathode magnetic field uses 5 to 9 magnets, preferably 7 magnets, to improve the utilization rate of the target material.

[0014] A plurality of metal targets are arranged side by side on the surface of the cathode magnetic field of the transition layer deposition chamber, and the magnetic lines of force on each target are closed to each other to form an unbalanced closed magnetic field.

[0015] Furthermore, the number of the metal targets is 1 to 3, and the spacing between the two symmetrical targets is 2 to 30 cm, preferably 5 to 20 cm.

[0016] Furthermore, a pure metal target material is installed on each of the metal target positions, and the pure metal target material includes one of transition metals such as titanium, chromium, niobium, zirconium, etc., and is used for deposition of a metal transition layer.

[0017] The power source connected to the target position of the transition layer deposition chamber adopts a high-power pulsed magnetron sputtering power source and a DC sputtering power source coupled to each other, and the two are connected through a power matcher, which effectively improves the bonding performance and density of the transition layer.

[0018] A plurality of carbide target positions are arranged side by side on the surface of the cathode magnetic field of the metal carbide layer deposition chamber, and the magnetic field on each carbide target position is a balanced magnetic field.

[0019] Furthermore, a pure metal target, a metal carbide target or a multinary silicon-carbon ceramic target is installed on each of the carbide target positions; the pure metal target is one of transition metals such as titanium, chromium, niobium, zirconium, etc., the metal carbide target is one of carbides of transition metals such as titanium carbide, chromium carbide, niobium carbide, zirconium carbide, etc., and the multinary silicon-carbon ceramic target is one of compounds composed of transition metals and multiple elements such as silicon and carbon, such as titanium silicon carbon and chromium silicon carbon.

[0020] Furthermore, the number of the carbide targets is 1 to 3, and the spacing between the two symmetrical targets is 2 to 20 cm, preferably 2 to 10 cm.

[0021] The power source connected to the target position of the metal carbide layer deposition chamber is a DC sputtering power supply or a pulsed sputtering power supply; when the target material of the target position is a metal carbide target material or a multi-component silicon-carbon ceramic target material, the target material can be directly sputtered to complete the preparation of the metal carbide layer; when the target material of the target position is a pure metal target material, the pure metal target material is sputtered by carbon source gas reaction to complete the preparation of the metal carbide layer.

[0022] Furthermore, when a pure metal target is sputtered by using a carbon source gas, the carbon source gas includes one of carbon-containing organic gases such as methane, acetylene, benzene, and pyridine.

[0023] Furthermore, reducing gas vents are provided on both sides of the target position in the metal carbide layer deposition chamber; the reducing gas is hydrogen to promote the formation of metal carbide crystals and improve the conductivity and corrosion properties of the metal carbide coating.

[0024] Furthermore, the hydrogen flow rate is controlled within a range of 2 to 500 sccm, preferably 5 to 20 sccm.

[0025] Compared with the prior art, the present invention has the following characteristics:

[0026] (1) By combining unbalanced and balanced magnetic fields, the matching of magnetic field mode, power supply system and target-substrate distance is optimized to further improve the bonding performance and stability of metal carbide coatings;

[0027] (2) Introducing reducing gas hydrogen during the deposition process of metal carbide coating to promote the formation of metal carbide crystals and improve the conductivity and corrosion resistance of the coating;

[0028] (3) The use of continuous small-scale deposition equipment and the introduction of automated equipment such as robots can achieve rapid deposition of metal carbide coatings, which can reduce the cost of coating preparation. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the structure of the four-chamber deposition system for metal carbide coatings of the invention;

[0030] Figure 2 It is a schematic diagram of the power supply and magnetic field of the transition layer deposition chamber;

[0031] Figure 3 It is a schematic diagram of the power supply and magnetic field of the metal carbide deposition chamber;

[0032] Figure 4 It is a schematic diagram of the output current of the power supply of the transition layer deposition chamber;

[0033] Explanation of the markings in the figure: 1-film inlet chamber, 2-transition layer deposition chamber, 3-metal carbide layer deposition chamber, 4-film outlet chamber, 5-chamber valve, 6-sample rack, 7-sample, 8-sample transmission device, 9-metal target position, 10-carbide target position, 11-ventilation pipe, 12-heating device, 13-cathode magnetic field. DETAILED DESCRIPTION

[0034] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0035] Example 1

[0036] Figure 1 The figure shows a four-chamber deposition system for a fuel cell plate metal carbide coating of the present invention, which mainly includes four vacuum chambers, which are, from left to right, a film input chamber 1, a transition layer deposition chamber 2, a metal carbide layer deposition chamber 3 and a film output chamber 4; the inlet and outlet of each chamber are provided with chamber valves 5 to separate the chambers on both sides from each other; a sample transmission device 8 passes through the bottom of each chamber to form a closed loop; a sample rack 6 is arranged on the sample transmission device 8, driving the sample 7 to pass through each chamber from left to right in turn to complete the preparation of the coating.

[0037] The film inlet chamber 1, the transition layer deposition chamber 2, the metal carbide layer deposition chamber 3 and the film outlet chamber 4 are respectively equipped with independent vacuum systems, power supply systems and gas circuit systems.

[0038] The film input chamber 1 is used for evacuating air and cleaning the sample, the transition layer deposition chamber 2 is used for depositing a metal transition layer on the surface of the cleaned sample, the metal carbide layer deposition chamber 3 is used for depositing a surface metal carbide layer, and the film output chamber 4 is used for cooling and venting the sample, thereby completing the preparation of a set of coatings.

[0039] Embodiments 2 to 7

[0040] Embodiments 2 to 7 have the same structure as embodiment 1, and have some additional features:

[0041] In Example 2, the cleaning method in the film feeding chamber 1 includes radio frequency self-bias cleaning, pulse bias cleaning and ion source cleaning symmetrically arranged on both sides of the chamber, and hydrogen is introduced into the chamber to etch the oxide on the surface of the sample.

[0042] In Example 2, the bias voltage during cleaning is 100-1000 V; the hydrogen flow rate used in the etching process is 5-500 sccm, and the cleaning time is 0.2-5 min.

[0043] In Example 3, 2 to 20 fuel cell plates can be hung on the sample rack 6, and a robotic arm or other similar automated device is used to complete the loading and unloading process of the fuel cell plates by clamping or adsorption; the running speed of the sample rack 6 on the sample transmission device 8 is 0.2 to 10 m / min.

[0044] In Example 3, a certain number of heating devices 12 are symmetrically and evenly arranged on both side walls of the transition layer deposition chamber 2 and the metal carbide layer deposition chamber 3 for heating the sample; the deposition temperature of the transition layer deposition chamber 2 is 0 to 700°C, and the deposition temperature of the metal carbide layer deposition chamber 3 is 0 to 1000°C.

[0045] Furthermore, cathode magnetic fields 13 are provided on both side walls of the transition layer deposition chamber 2 and the metal carbide layer deposition chamber 3, respectively, and are arranged at intervals from the heating device 12. The cathode magnetic field 13 uses 5 to 9 magnets. In Example 3, the cathode magnetic field uses 7 magnets, and the target material utilization rate reaches the highest level.

[0046] A plurality of metal targets 9 are arranged side by side on the surface of the cathode magnetic field 13 of the transition layer deposition chamber 2, and the magnetic lines of force on each metal target 9 are closed to each other, forming an unbalanced closed magnetic field. Figure 2 As shown; the number of the metal targets 9 is 1 to 3, and the spacing between the two symmetrical targets is 2 to 30 cm. In Example 4, it is set to 5 to 20 cm to achieve the best.

[0047] Furthermore, a pure metal target material is installed on each of the metal target positions 9 , and the pure metal target material includes one of transition metals such as titanium, chromium, niobium, zirconium, etc., and is used for deposition of a metal transition layer.

[0048] The power source connected to the metal target position 9 adopts a high-power pulsed magnetron sputtering power source and a DC sputtering power source coupled to each other, such as Figure 2 As shown, the two are connected through a power matcher, which can effectively improve the bonding performance and density of the transition layer; in Example 5, the deposition time of the sample in the transition layer deposition chamber 2 is 0.2 to 3 minutes.

[0049] In Example 5, a plurality of carbide targets 10 are arranged side by side on the surface of the cathode magnetic field 13 of the metal carbide layer deposition chamber 3, and the magnetic field on each target is a balanced magnetic field, such as Figure 3 The number of the carbide targets 10 is 1 to 3, and the spacing between the two symmetrical targets is 2 to 20 cm. In Example 5, the spacing is set to 2 to 10 cm to achieve the best result.

[0050] A pure metal target, a metal carbide target or a multi-component silicon-carbon ceramic target is installed on each of the carbide target positions 10; the pure metal target is one of transition metals such as titanium, chromium, niobium, zirconium, etc., the metal carbide target is one of carbides of transition metals such as titanium carbide, chromium carbide, niobium carbide, zirconium carbide, etc., and the multi-component silicon-carbon ceramic target is one of compounds composed of transition metals and multiple elements such as silicon and carbon, such as titanium silicon carbon and chromium silicon carbon. In Example 6, the target of the carbide target position 10 is a metal carbide target, preferably a titanium carbide target; the deposition time of the sample in the metal carbide layer deposition chamber 3 is 0.2 to 2 minutes.

[0051] The power supply connected to the carbide target 10 is a DC sputtering power supply or a pulsed sputtering power supply; when the target material of the carbide target 10 is a metal carbide target material or a multi-component silicon-carbon ceramic target material, the target material can be directly sputtered to complete the preparation of the metal carbide layer; when the target material of the carbide target 10 is a pure metal target material, the pure metal target material is sputtered by carbon source gas reaction to complete the preparation of the metal carbide layer.

[0052] Furthermore, when a pure metal target is sputtered by using a carbon source gas, the carbon source gas includes one of carbon-containing organic gases such as methane, acetylene, benzene, and pyridine; in Example 6, the preferred carbon source gas is acetylene.

[0053] In Example 7, reducing gas ventilation pipes 11 are provided on both sides of the metal target 9 and the carbide target 10; the reducing gas is hydrogen to promote the formation of metal carbide crystals and improve the conductivity and corrosion resistance of the metal carbide coating.

[0054] Furthermore, the hydrogen flow rate is controlled at 2-500 sccm. In Example 7, the preferred hydrogen flow rate is 5-20 sccm.

Claims

1. A four-chamber deposition system for metal carbide coatings on fuel cell plates, characterized in that: Mainly include: The chambers are, in sequence, a film inlet chamber (1), a transition layer deposition chamber (2), a metal carbide layer deposition chamber (3), and a film outlet chamber (4); the inlet and outlet of each chamber are provided with chamber valves (5) to separate the chambers on both sides from each other; a sample transmission device (8) passes through the bottom of each chamber to form a closed loop; a sample rack (6) is provided on the sample transmission device (8) to drive the sample (7) to pass through each chamber from left to right in sequence to complete the preparation of the coating; A certain number of heating devices (12) are symmetrically and evenly arranged on both side walls of the transition layer deposition chamber (2) and the metal carbide layer deposition chamber (3); cathode magnetic fields (13) are provided on both side walls of the transition layer deposition chamber (2) and the metal carbide layer deposition chamber (3), and are arranged at intervals from the heating devices (12); A plurality of metal target positions (9) are arranged side by side on the surface of the cathode magnetic field (13) of the transition layer deposition chamber (2), and the magnetic lines of force on each metal target position (9) are closed to each other, forming an unbalanced closed magnetic field; the number of the metal target positions (9) is 1 to 5, and the spacing between the two symmetrical target positions is 2 to 30 cm; a plurality of carbide target positions (10) are arranged side by side on the surface of the cathode magnetic field (13) of the metal carbide layer deposition chamber (3), and the magnetic field on each target position is a balanced magnetic field; the number of the carbide target positions (10) is 1 to 5, and the spacing between the two symmetrical target positions is 2 to 20 cm; the power supply connected to the metal target position (9) adopts a high-power pulsed magnetron sputtering power supply and a DC sputtering power supply coupled to each other, and the two are connected through a power supply matcher; The target material of the carbide target position (10) is a metal carbide target material; reducing gas ventilation pipes (11) are respectively provided on both sides of the metal target position (9) and the carbide target position (10), and the reducing gas is hydrogen.

2. The four-chamber deposition system according to claim 1, characterized in that: The film input chamber (1), the transition layer deposition chamber (2), the metal carbide layer deposition chamber (3) and the film output chamber (4) are respectively equipped with independent vacuum systems, power supply systems and gas circuit systems.

3. The four-chamber deposition system according to claim 1, characterized in that: 2 to 20 fuel cell plates can be hung on the sample rack (6).

4. The four-chamber deposition system according to claim 1, characterized in that: The cathode magnetic field (13) uses 5 to 9 magnets.

5. The four-chamber deposition system according to claim 1, characterized in that: A pure metal target material is installed on each of the metal target positions (9), and the pure metal target material is one of the transition metals.

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