Composite hydrogen barrier coating processing method and composite hydrogen barrier coating

Abstract

The present invention discloses a composite hydrogen barrier coating processing method and a composite hydrogen barrier coating, wherein the third hydrogen barrier layer obtained by the processing method does not have grain boundary defects of crystalline materials and has excellent hydrogen barrier performance. It is a surface layer that can greatly increase the difficulty of penetrating the surface layer; the first and second hydrogen barrier layers are processed by a closed unbalanced magnetron sputtering process, so that their grain size is finer and the coating has high density, which can greatly improve their own hydrogen barrier performance; the three hydrogen barrier layers are superimposed together, so that the difficulty of hydrogen atoms penetrating into different layers increases geometrically. A relatively low process temperature is used, on the one hand, so that the grains of the first and second hydrogen barrier layers will not increase excessively, thereby obtaining a coating with small grains and denseness; on the other hand, it can ensure that the third hydrogen barrier layer has sufficient hardness and avoid the problem that the temperature is too high, which easily causes the substrate to be tempered and deformed, thereby affecting and failing the first, second, and third hydrogen barrier layers.

Description

Technical Field

[0001] The invention relates to the field of hydrogen barrier materials, in particular to a composite hydrogen barrier coating processing method and a composite hydrogen barrier coating. Background Art

[0002] Hydrogen is currently widely used in all walks of life because of its safety, wide sources, high calorific value, and cleanliness. Hydrogen is usually stored in liquid form in metal hydrogen storage containers. When hydrogen and isotopes penetrate into metal materials, the performance of the metal materials will deteriorate and structural hydrogen damage will occur. Therefore, covering the surface of metal materials with hydrogen barrier coatings is of great significance to solve the problem of hydrogen penetration.

[0003] For example, the Chinese invention patent application with application publication number CN113122842A discloses a composite hydrogen barrier coating and a preparation method thereof, which comprises an alternately arranged metal transition layer and a corresponding metal oxide ceramic coating.

[0004] Another example is the Chinese invention patent with the authorization announcement CN104561891B, which discloses a dual-component gradient hydrogen permeation barrier coating and a preparation method thereof, which includes a Cr coating, a Cr-O component gradient coating, a Cr-Al-O component gradient coating, an Al-O component gradient coating and an A306O3 coating arranged in sequence.

[0005] Although they all use a multi-layer composite structure to improve the hydrogen barrier performance, each layer of coating is composed of grains, and there will be more or less gaps between the grains, which leads to certain limitations on the hydrogen barrier performance of each layer. Summary of the invention

[0006] The purpose of the present invention is to solve the above problems existing in the prior art and to provide a composite hydrogen barrier coating processing method and a composite hydrogen barrier coating.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] A method for processing a composite hydrogen barrier coating comprises the following steps:

[0009] S1, cleaning the substrate;

[0010] S2, depositing a first hydrogen barrier layer on the cleaned substrate using a closed unbalanced magnetron sputtering process;

[0011] S3, depositing a second hydrogen barrier layer on the first hydrogen barrier layer using a closed unbalanced magnetron sputtering process;

[0012] S4, depositing a third hydrogen barrier layer on the second hydrogen barrier layer, wherein the third hydrogen barrier layer is an amorphous structure;

[0013] When depositing the first hydrogen barrier layer, the second hydrogen barrier layer and the third hydrogen barrier layer, the deposition temperature is controlled not to exceed 200°C.

[0014] Preferably, in the composite hydrogen barrier coating processing method, the thickness of the second hydrogen barrier layer is between 2 and 20 microns.

[0015] Preferably, in the composite hydrogen barrier coating processing method, the thickness of the third hydrogen barrier layer is between 1 and 10 microns.

[0016] Preferably, in the method for processing the composite hydrogen barrier coating, the third hydrogen barrier layer is a diamond-like carbon film, and its thickness is between 1 and 5 microns.

[0017] Preferably, in the composite hydrogen barrier coating processing method, controlling the deposition temperature not to exceed 200° C. is achieved by alternately performing coating and cooling.

[0018] Preferably, in the composite hydrogen barrier coating processing method, the deposition temperature is controlled between 100-150°C.

[0019] Preferably, in the composite hydrogen barrier coating processing method, each coating time is 10-30 minutes, and each cooling time is 10-30 minutes.

[0020] Preferably, in the composite hydrogen barrier coating processing method, the cooling is achieved by introducing argon gas circulation cooling and water circulation cooling into the deposition furnace.

[0021] Preferably, in the composite hydrogen barrier coating processing method, the cooling water temperature of the water circulation cooling is controlled between 15°C and 25°C.

[0022] The composite hydrogen barrier coating is obtained by processing using any of the processing methods described above.

[0023] The advantages of the technical solution of the present invention are mainly reflected in:

[0024] The present invention makes the third hydrogen barrier layer of the surface layer an amorphous structure, which does not have the grain boundary defects of the crystalline material and has excellent hydrogen barrier performance. It is set on the surface layer, which greatly increases the difficulty of hydrogen atoms breaking through the surface layer, thereby reducing the probability of hydrogen penetrating into other layers; the first and second hydrogen barrier layers are processed by closed unbalanced magnetron sputtering process, so that their grain size is finer and the coating density is high, so that they themselves have higher hydrogen barrier performance; the three hydrogen barrier layers are superimposed together to make up for the gaps in each layer, so that the difficulty of hydrogen atoms penetrating in each layer is increased, and the difficulty of penetrating between layers is greatly increased. The use of a relatively low process temperature can effectively prevent the grains of the first and second hydrogen barrier layers from excessively increasing, thereby obtaining a coating with small grains and denseness. Secondly, it can ensure that the third hydrogen barrier layer has sufficient hardness and avoid the problem that the temperature is too high, which easily causes the substrate to be tempered and deformed, thereby affecting and failing the first, second, and third hydrogen barrier layers, thereby ensuring the stability of the structure.

[0025] The third hydrogen barrier layer of the present invention adopts a diamond-like coating, and its thickness is controlled between 1.5-2.5 microns, which can effectively ensure that the surface layer has sufficient hydrogen barrier ability, while avoiding the problem that the diamond-like coating is too thick and causes the bonding force to weaken and affect the stability of the coating.

[0026] The present invention improves the deposition furnace so that the deposition furnace can not only effectively improve the coating quality and density of closed unbalanced magnetron sputtering, but also realize the combination of different cleaning processes to improve the cleaning quality and effect.

[0027] The present invention adopts the method of alternating coating and cooling to carry out coating, which can conveniently control the coating temperature and control the deposition temperature between 100°C and 150°C, thereby ensuring that the grain size will not be too large and that the substrate will not be tempered. At the same time, the cooling adopts a combination of argon circulation cooling and water circulation cooling, which can greatly improve the cooling rate, thereby improving the overall deposition efficiency, and can achieve an effective combination of grain size control, high efficiency and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a schematic diagram of the composite hydrogen barrier coating of the present invention;

[0029] Figure 2 is a cross-sectional morphology diagram of the third hydrogen barrier layer of the present invention under SEM (scanning electron microscope);

[0030] Figure 3 This is a surface morphology image of the first hydrogen barrier layer of the present invention after being magnified 50,000 times under SEM;

[0031] Figure 4 is a schematic diagram of a deposition furnace of the present invention;

[0032] Figure 5 It is a structural schematic diagram of the anode layer ion source of the present invention;

[0033] Figure 6 This is a surface structure diagram of the first hydrogen barrier layer or the second hydrogen barrier layer deposited by the deposition furnace of the present invention at a coil current of 5A. In the diagram, the coating surface is a dense crystal structure in which columnar crystals disappear. DETAILED DESCRIPTION

[0034] The objects, advantages and features of the present invention will be illustrated and explained by the non-limiting description of the following preferred embodiments. These embodiments are only typical examples of the application of the technical solution of the present invention. Any technical solution formed by equivalent replacement or equivalent transformation falls within the scope of protection claimed by the present invention. In the description of the scheme, it should be noted that the orientation or position relationship indicated by the terms "center", "upper", "lower", "left", "right", "front", "back", "vertical", "horizontal", "inside", "outside", etc. is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of description and simplified description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0035] The composite hydrogen barrier coating processing method disclosed by the present invention is described below in conjunction with the accompanying drawings, which includes the following steps:

[0036] S1, cleaning the substrate 100;

[0037] S2, depositing a first hydrogen barrier layer 200 on the cleaned substrate 100 using a closed unbalanced magnetron sputtering process;

[0038] S3, depositing a second hydrogen barrier layer 300 on the first hydrogen barrier layer 200 using a closed unbalanced magnetron sputtering process;

[0039] S4, depositing a third hydrogen barrier layer 400 on the second hydrogen barrier layer 300, wherein the third hydrogen barrier layer 400 is an amorphous structure, thereby obtaining the following Figure 1 The composite hydrogen barrier coating shown.

[0040] As attached Figure 2 As shown, the third hydrogen barrier layer 400 of the present invention is an amorphous structure, which does not have the grain boundary defects of the crystalline material, so the coating has almost no gaps, and thus has excellent hydrogen barrier performance. The first hydrogen barrier layer 200 and the second hydrogen barrier layer 300 are obtained by using a closed unbalanced magnetron sputtering process, so that the grain sizes of the first hydrogen barrier layer 200 and the second hydrogen barrier layer 300 are as shown in the attached Figure 3As shown, the density of the coating is effectively improved, and the gaps between the grains are reduced, thereby effectively improving the hydrogen barrier properties of the first hydrogen barrier layer 200 and the second hydrogen barrier layer 300. Stacking three membrane layers with good hydrogen barrier properties together can effectively fill the gaps in the membrane layers, thereby increasing the difficulty of hydrogen atoms penetrating into different membrane layers exponentially.

[0041] Since a closed unbalanced magnetron sputtering process is required to deposit the first hydrogen barrier layer 200 and the second hydrogen barrier layer 300, the deposition furnace used in the processing of the composite hydrogen barrier coating of the present invention can be a known closed unbalanced magnetron sputtering device. Furthermore, considering the need to improve the substrate cleaning quality and the need to improve the density of the film layer to improve the hydrogen barrier ability, in this embodiment, the deposition furnace adds an ion beam source to the known closed unbalanced magnetron sputtering device to improve the cleaning effect, and at the same time adds an electromagnetic coil to optimize the magnetic field closure, so that the plasma density of the magnetron sputtering is increased, so that the crystal size of the first hydrogen barrier layer and the second hydrogen barrier layer prepared by using this deposition furnace is smaller, the coating is denser, and has a better hydrogen barrier effect.

[0042] Specifically, as attached Figure 4 As shown, the deposition furnace includes a furnace body 10, a rotating frame 20, an ion beam source 30, a magnetron sputtering target 40, an electromagnetic coil 50 and a power supply assembly. The rotating frame 20 is arranged in the furnace body 10, and the rotating frame 20 is used to fix the substrate and can drive the substrate to rotate at least one level. The ion beam source 30 is distributed around the rotating frame 20, and the number is preferably two and symmetrically distributed on the opposite sides of the rotating frame 20; the ion beam source 30 can be various known feasible ion beam sources, preferably an anode layer ion source.

[0043] As attached Figure 5 As shown, the anode layer ion source includes an inner cathode 301, an outer cathode 302, an anode 303 and a permanent magnet 304. The outer cathode 302 is located outside the inner cathode 301. The anode 303 is arranged below the inner cathode 301 and the outer cathode 302 and is opposite to the gap between the inner and outer cathodes. The permanent magnet 304 is located between the anode 303 and below the inner cathode 301.

[0044] As attached Figure 5As shown, in the present invention, the horizontal distance 305 between the inner and outer cathodes is set between 4-8mm, and the distance 306 between the cathode and the anode in the height direction is set between 4-8mm. The reason for this design is that when the inter-electrode spacing of the glow discharge is close, when the voltage of the ion beam source 30 is 1500V-2000V during operation, breakdown is likely to occur under high working pressure, resulting in instability. Increasing the inter-electrode spacing of the glow discharge can effectively reduce the occurrence of arcing, so that the ion beam can work stably under higher pressure. Further, the anode layer ion source adopts a pulse power supply, and the duty cycle of the pulse power supply during operation is controlled within 40%, which can effectively suppress the arcing phenomenon of the ion beam under high voltage 1500-2000V and high pressure 0.6-1.5Pa, so that the ion beam can work more stably under higher working pressure. This effectively solves the problem that ion beam cleaning and bias glow cleaning are difficult to clean at the same time due to different working pressures.

[0045] Furthermore, the magnetic induction intensity of the permanent magnet 304 is set between 450-550 mT (milli-Tesla). The reason for this design is that the increase in the above-mentioned inter-pole spacing causes the weakening of ion energy, resulting in a worse cleaning effect, while the setting of the magnetic induction intensity of the above-mentioned permanent magnet 304 can effectively enhance the ion energy and ensure that the cleaning effect is achieved.

[0046] As attached Figure 4 As shown, the magnetron sputtering targets 40 are arranged around the rotating frame 20, and the number of the magnetron sputtering targets 40 can be designed as needed. Preferably, there are 1-3 pairs of the magnetron sputtering targets 40, and each pair of the magnetron sputtering targets 40 is symmetrically arranged on both sides of the rotating frame 20. The magnetron sputtering targets 40 can be various known sputtering target materials, and preferably they are unbalanced magnetron sputtering targets 40 and form a closed magnetic well 90.

[0047] As attached Figure 4 As shown, the electromagnetic coil 50 corresponds to the magnetron sputtering target 40 one by one and is arranged around the periphery of each magnetron sputtering target 40, which can enhance the closure of the magnetic field, reduce electron escape, increase the plasma concentration in the workpiece area, increase the bias current, and improve the film formation rate. The obtained coated material has smaller grains and higher density, thereby effectively reducing the gaps in the film and increasing the difficulty of hydrogen atom penetration.

[0048] In actual processing, in S1, in order to ensure the quality and efficiency of substrate cleaning, the cleaning of the substrate 100 in this embodiment includes the following steps:

[0049] S11, placing the substrate 100 on a rotating rack in a deposition furnace.

[0050] S12, evacuating the deposition furnace to a predetermined vacuum degree, for example, 0.05Pa.

[0051] S13, filling argon gas into the deposition furnace until the gas pressure in the deposition furnace is between 0.6-1.5Pa.

[0052] S14, turn on the bias power supply 60 and the ion beam source 30 to implement bias glow cleaning and ion beam cleaning to clean the substrate simultaneously, and the time for the bias glow cleaning and ion beam cleaning to clean the substrate simultaneously does not exceed 1 hour, preferably does not exceed 45 minutes, and the most optimal is about 30 minutes.

[0053] In specific operation, the bias power supply 60 is turned on first, and then the ion beam sources 30 are turned on one by one. The voltage of the bias power supply 60 during operation is between 700-2000V, preferably between 800V-2000V. At this time, a large bias current (2-30A, preferably 15-30A) can be obtained, so that a better cleaning effect can be achieved. The voltage of the ion beam source 30 during operation is between 300-2000V, preferably between 1500V-2000V.

[0054] After effectively combining the two cleaning methods, the advantages of large area and high efficiency of bias glow cleaning effectively make up for the problems of small bias current and low efficiency of ion beam cleaning. At the same time, the large plasma energy and directionality of ion beam cleaning effectively make up for the defects of insufficient plasma energy of bias glow cleaning and the inability to perform high-quality cleaning of corner areas and anisotropic positions due to uneven glow distribution, achieving a perfect combination of cleaning effect and cleaning efficiency.

[0055] The specific process of using the unbalanced magnetron sputtering deposition process to deposit the first hydrogen barrier layer and the second hydrogen barrier layer in S2 and S3 is a known technology and will not be described in detail here. It should be noted that during deposition, the current of the electromagnetic coil is controlled to be about 5A, which can make the coating more dense. Figure 6 shown.

[0056] In actual production, the inventors have found that metal materials such as titanium, nickel, and chromium have good bonding strength with the substrate 100 during deposition, and the grains are refined. Therefore, in S2, the first hydrogen barrier layer 200 can be a titanium layer, a nickel layer, or a chromium layer. The specific thickness of the first hydrogen barrier layer 200 can be designed according to the bonding strength to be achieved, and is not limited here.

[0057] In S3, the second hydrogen barrier layer 300 can be a nitride or oxide such as chromium nitride, titanium nitride or tungsten carbide. The inventors further discovered that: since titanium nitride has a high melting point and good thermal stability, it can also refine the titanium grains and make the crystal structure more compact, thereby achieving a good hydrogen barrier effect. Therefore, the second hydrogen barrier layer 300 is preferably a titanium nitride layer, and correspondingly, the first hydrogen barrier layer 200 is a titanium layer. In addition, the thickness of the second hydrogen barrier layer 300 is preferably between 2-20, and preferably between 2.5-15 microns. Such a thickness enables the second hydrogen barrier layer 300 to have a stable hydrogen barrier effect, while being able to provide sufficient support for the third hydrogen barrier layer 400 and ensure the need for bonding.

[0058] The third hydrogen barrier layer 400 is preferably a diamond-like film, which can be prepared by ionizing hydrocarbon gas through the known anode layer ion beam; it can also be prepared by cathode arc plus curved tube filtration, which is to evaporate ionized target molecules through arc discharge, obtain pure ion flow through curved tube filtration to prepare a diamond-like film; of course, the diamond-like film can also be obtained by PECVD deposition.

[0059] The thickness of the third hydrogen barrier layer 400 is between 1 and 10 microns, more preferably, the thickness of the third hydrogen barrier layer 400 is between 1.5 and 5 microns, and most preferably between 1.5 and 2.5 microns. This is because the diamond-like carbon film is a brittle material, and its increased thickness easily leads to a decrease in bonding strength, while the second hydrogen barrier layer 300 composed of titanium nitride has good bonding strength. Therefore, on the basis of ensuring sufficient hydrogen barrier ability, the thickness of the third hydrogen barrier layer 400 can be reduced, and the thickness of the second hydrogen barrier layer 300 can be increased, so that the hydrogen barrier effect of the entire coating is improved while having stable bonding strength.

[0060] When depositing the first, second, and third hydrogen barrier layers, the deposition temperature of each layer is controlled not to exceed 200°C, and a lower deposition temperature is used to process the first, second, and third hydrogen barrier layers. On the one hand, it can effectively cooperate with the closed unbalanced magnetron sputtering process to make the grains of the first hydrogen barrier layer 200 and the second hydrogen barrier layer 300 as small as possible and the coating more dense. Furthermore, it can effectively ensure that the third hydrogen barrier layer 400 has sufficient hardness to improve the stability of the structure and reduce the risk of the surface being damaged by external forces. More importantly, when the deposition temperature is too high, it is easy to cause the substrate 100 to temper and reduce the hardness and strength, which makes the substrate 100 prone to deformation and poor bonding with the coating, and ultimately makes the first hydrogen barrier layer 200, the second hydrogen barrier layer 300, and the third hydrogen barrier layer 400 fail. The lower process temperature effectively avoids this situation.

[0061] The control of the deposition temperature not exceeding 200° C. is achieved by alternately performing coating and cooling. Taking the deposition of the first hydrogen barrier layer 200 as an example, during deposition, the sputtering power source 70 is first turned on for coating. After 10-30 minutes of coating, the sputtering power source 70 is turned off for cooling. After 10-30 minutes of cooling, the sputtering power source 70 is turned on again for coating. After 10-30 minutes of coating, the sputtering power source 70 is turned off again for cooling. This alternation is repeated until the thickness of the first hydrogen barrier layer 200 reaches the target value and stops.

[0062] The specific cooling is achieved by introducing argon circulation cooling and water circulation cooling into the deposition furnace. The argon circulation cooling is achieved by continuously filling argon into the deposition furnace each time the coating is stopped, and vacuuming is achieved by the vacuum pumping system. The water circulation cooling is achieved by delivering cooling water to the water-cooled plate at the appropriate position in the deposition furnace through the cooling water circulation system each time the coating is stopped. The specific position of the cooling plate can be designed as needed and is not limited here. The specific structure of the cooling water circulation system is a known technology and is not described here in detail. The temperature of the cooling water supplied to the water-cooled plate is controlled between 15°C and 25°C.

[0063] Combining the two cooling methods can increase the cooling rate to reach the target cooling temperature in the shortest possible time, which is beneficial to increase the overall deposition rate. Preferably, when each layer is deposited, the deposition temperature is preferably controlled between 100°C and 150°C, which can effectively shorten the cooling time and reduce the cooling cost, thereby achieving a perfect combination of low cost, high efficiency and good coating quality.

[0064] Example 2

[0065] This embodiment discloses a composite hydrogen barrier coating, which is obtained by processing using the processing method of the above embodiment. The composite hydrogen barrier coating can be used in various application fields that require preventing hydrogen penetration, such as in hydrogen storage containers.

[0066] Example 3

[0067] This embodiment discloses a hydrogen storage container, including a substrate 100, on which a first hydrogen barrier layer 200, a second hydrogen barrier layer 300 and a third hydrogen barrier layer 400 are sequentially arranged from the inside to the outside. The third hydrogen barrier layer 400 is an amorphous structure, specifically a diamond-like film layer, and its thickness is between 1.5-5 microns.

[0068] There are many implementation methods of the present invention, and all technical solutions formed by equivalent transformation or equivalent transformation fall within the protection scope of the present invention.

Claims

1. A method for processing a composite hydrogen barrier coating, characterized in that: The steps include: S1, cleaning the substrate; S2, depositing a first hydrogen barrier layer on the cleaned substrate using a closed unbalanced magnetron sputtering process; S3, depositing a second hydrogen barrier layer on the first hydrogen barrier layer using a closed unbalanced magnetron sputtering process; S4, depositing a third hydrogen barrier layer on the second hydrogen barrier layer, wherein the third hydrogen barrier layer is an amorphous structure; When depositing the first hydrogen barrier layer, the second hydrogen barrier layer and the third hydrogen barrier layer, the deposition temperature is controlled not to exceed 200° C.; The S1 comprises the following steps: S11, placing the substrate on a rotating rack in a deposition furnace; S12, evacuating the deposition furnace to a predetermined vacuum degree; S13, filling the deposition furnace with argon gas until the gas pressure in the deposition furnace is between 0.6-1.5 Pa; S14, turning on the bias power supply and the ion beam source to implement bias glow cleaning and ion beam cleaning to clean the substrate simultaneously; The ion beam sources arranged in the vacuum chamber are anode layer ion sources and are evenly distributed around the workpiece holder; the voltage of the bias power supply when working is between 700-2000V; the voltage of the ion beam source when working is between 300-2000V; the horizontal distance between the inner cathode and the outer cathode of the anode layer ion source is between 4-8mm, and the distance between the cathode and cathode in the height direction is between 4-8mm; the air pressure in the vacuum chamber is between 0.6-10Pa.

2. The method for processing the composite hydrogen barrier coating according to claim 1, characterized in that: The thickness of the second hydrogen barrier layer is between 2 and 20 microns.

3. The method for processing the composite hydrogen barrier coating according to claim 1, characterized in that: The control of the deposition temperature not exceeding 200° C. is achieved by alternately performing coating and cooling.

4. The method for processing the composite hydrogen barrier coating according to claim 3, characterized in that: The deposition temperature is controlled between 100-150°C.

5. The method for processing the composite hydrogen barrier coating according to claim 3, characterized in that: Each coating process takes 10-30 minutes, and each cooling process takes 10-30 minutes.

6. The method for processing the composite hydrogen barrier coating according to claim 3, characterized in that: The cooling is achieved by introducing argon gas circulation cooling and water circulation cooling into the deposition furnace.

7. The method for processing the composite hydrogen barrier coating according to claim 6, characterized in that: The temperature of the cooling water in the water circulation cooling is controlled between 15°C and 25°C.

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