A high-hydrogen-flux metal film and a preparation process thereof

Abstract

The application relates to the technical field of separation membrane materials, and particularly discloses a high-hydrogen-flux metal film and a preparation process thereof. The application successfully realizes the operation of grain refinement of the metal film material by selecting a suitable nickel-based high-entropy alloy NiCoFeCrMn as a metal film base material and combining processes such as step-by-step deformation, segmented annealing and tempering, and obtains a high-hydrogen-flux metal film which is excellent in performance and high in yield. The technical scheme of the application effectively solves the problems such as great difficulty in thinning the dense layer, great reduction of the yield and dense performance caused by the grain boundary regulation in the technical path of improving the hydrogen flux of the dense metal film in the prior art.

Description

Technical Field

[0001] This invention relates to the field of separation membrane materials technology, and in particular to a high hydrogen flux metal membrane and its preparation process. Background Technology

[0002] Dense metal membranes are core materials for hydrogen purification and separation in the hydrogen energy field, and their hydrogen permeation performance directly determines the efficiency and cost of hydrogen energy utilization. Hydrogen permeation in dense metal membranes follows a dissolution-diffusion mechanism: hydrogen first dissolves on the membrane surface and then diffuses through the lattice and grain boundaries inside the membrane. In this process, increasing the hydrogen flux (the amount of hydrogen permeating per unit area per unit time) is the core technological goal in this field.

[0003] However, in existing technologies, the main approaches to increasing hydrogen flux include thinning the dense layer or controlling grain boundaries during sintering, but both of these have significant limitations:

[0004] Thinning of the dense layer: Theoretically, the smaller the thickness of the dense layer, the lower the hydrogen permeation resistance and the higher the flux. However, in practice, precise control of the dense layer thickness requires extremely high process precision (e.g., pinholes and cracks are prone to occur in the preparation of ultrathin films), and excessive thinning will seriously damage the structural integrity of the membrane, leading to a sharp drop in yield (usually below 50%), while significantly deteriorating the long-term operational stability of the membrane (e.g., plastic deformation is prone to occur at high temperatures), which greatly limits industrial applications.

[0005] Grain boundary control: Studies have shown that grain boundaries are a superior pathway for rapid hydrogen diffusion. The smaller the grain size and the higher the grain boundary density, the more rapid diffusion channels available for hydrogen, which not only increases the permeation rate but also reduces the permeation activation energy and energy consumption. However, existing methods for controlling grain boundary density through low-temperature sintering can lead to a decrease in density (excessive helium leakage rate) due to insufficient sintering of the metal film, resulting in a lower yield (usually below 60%). It is difficult to achieve a balance between "thinning the dense layer or controlling grain boundaries during sintering to increase hydrogen flux" and "production stability".

[0006] In summary, existing technologies for improving hydrogen flux in dense metal films suffer from challenges such as difficulty in thinning the dense layer and significant reductions in yield and density performance due to grain boundary manipulation. Therefore, there is an urgent need to develop a technology that can significantly improve hydrogen flux while ensuring the integrity of the membrane structure and production stability, thus overcoming the shortcomings of existing technologies. Summary of the Invention

[0007] In view of this, the present invention provides a high hydrogen flux metal membrane and its preparation process.

[0008] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0009] The first aspect of this invention provides a process for preparing a high-hydrogen-flux metal membrane, comprising the following steps:

[0010] Step 1: Deform the metal film substrate to obtain a deformed metal film;

[0011] Step 2: Under a micro-reducing atmosphere, the deformed metal film is subjected to segmented annealing treatment, wherein the temperature of the first stage of annealing treatment is 400-500℃; the temperature of the second stage of annealing treatment is 550-650℃; the temperature of the third stage of annealing treatment is 700-800℃; and then cooled to room temperature to obtain a secondary-treated metal film.

[0012] Step 3: The secondary processed metal membrane is subjected to cyclic tempering at 300-400℃ to obtain a high hydrogen flux metal membrane.

[0013] In step one, the raw material for the metal film substrate includes a nickel-based high-entropy alloy NiCoFeCrMn.

[0014] In step two, the second stage of annealing is carried out by a staged programmed temperature rise to 550-650℃, with a heating rate of 8-12℃ / min and a holding time of 8-12min for each stage.

[0015] Compared to existing technologies, this invention designs a high-hydrogen-flux metal membrane preparation process, including the selection of the metal membrane substrate and a specific preparation process. Specifically, the membrane substrate selected in this invention is a nickel-based high-entropy alloy NiCoFeCrMn. This alloy is predominantly face-centered cubic (FCC) structure, with Ni and Co providing high-entropy stabilization effects. Cr and Mn optimize lattice parameters through solid solution strengthening, forming a uniform atomic arrangement that provides continuous channels for hydrogen atom dissolution and diffusion. Furthermore, Cr in the alloy can suppress hydrogen embrittlement, reduce hydrogen solubility, avoid the formation of brittle hydrides, and ensure the stability of the hydrogen permeation channels. Fe and Mn elements can suppress the chemical adsorption of CO on the membrane surface, reducing carbon buildup and clogging of the permeation channels. More importantly, the elemental content of the nickel-based high-entropy alloy NiCoFeCrMn is basically uniform, effectively preventing compositional segregation and brittle phase precipitation, allowing the metal membrane substrate to maintain high yield strength and plasticity at high temperatures.

[0016] The preparation process proposed in this invention first uses rolling to deform the metal film substrate, enabling it to accumulate sufficient recrystallization driving force. Moreover, rolling elongates the initial coarse grains into fibrous structures, providing a structural basis for the "crushing-recrystallization" during subsequent annealing, ultimately improving the grain refinement effect. The deformed metal film then undergoes segmented annealing. The first stage of annealing uses a temperature higher than the recrystallization initiation temperature to activate nucleation, but lower than the rapid growth temperature to prevent immediate coarsening after nucleation. The second stage of annealing ensures uniform grain growth, preventing uneven grain size. Traditional isothermal annealing is prone to "abnormal grain growth," while step-by-step heating allows for uniform grain growth, as each 10°C increase only allows small grains to grow preferentially, inhibiting the encroachment of large grains. The third stage of annealing is higher than the film's operating temperature to eliminate more than 90% of residual stress, but lower than the complete recrystallization temperature to prevent excessive grain coarsening. Through segmented annealing, the final grain size stabilizes at 1-3 μm, which is 5-10 times finer than traditional single-stage annealing. Finally, multiple cycles of tempering improve the film's elongation, reduce microhardness, and prevent cracking caused by vibration or installation stress during use, ensuring the structural stability of the film material.

[0017] Preferably, in step one, the metal film substrate is a hollow fiber membrane or a tubular membrane.

[0018] Preferably, in step one, the molar ratio of each element in the nickel-based high-entropy alloy NiCoFeCrMn is 1:1:1:1:1.

[0019] Preferably, in step one, the deformation treatment method includes rolling, stretching, or torsion.

[0020] Preferably, in step one, the deformed metal membrane is a tubular membrane or a hollow fiber membrane.

[0021] Preferably, in step one, the total deformation of the metal film substrate is 5%-65%.

[0022] More preferably, in step one, when the deformation treatment is rolling, the total deformation of the metal film substrate is 40%-65%.

[0023] More preferably, in step one, when the deformation treatment is stretching, the total deformation of the metal film substrate is 10%-35%.

[0024] More preferably, in step one, when the deformation treatment is torsion, the total deformation of the metal film substrate is 5%-20%.

[0025] More preferably, in step one, the diameter of the rolling roll is 200-300 mm, and the surface roughness Ra ≤ 0.1 μm.

[0026] More preferably, in step one, the rolling speed is 0.5-2 m / min and the rolling temperature is 50-80℃.

[0027] In a further preferred embodiment, in step one, when using rolling to perform deformation treatment, if the total deformation is ≥50%, a step-by-step rolling method is adopted, with a single rolling deformation of 5%-10%, and a heat preservation treatment is performed at 100-150℃ after each rolling.

[0028] This can better achieve the effect of stress relief, ensure that the stress in the metal film substrate is completely released, and avoid abnormal grain growth caused by stress concentration during subsequent annealing.

[0029] More preferably, the heat preservation treatment time is 30-60 minutes.

[0030] Excessive rolling temperature can trigger dynamic recrystallization, leading to a decrease in dislocation density and weakening the nucleation dynamics of subsequent recrystallization.

[0031] Preferably, in step two, the micro-reducing atmosphere is a mixture of argon and hydrogen, wherein the volume percentage of hydrogen is 5%-10%.

[0032] Preferably, in step two, the gas flow rate is 200-500 mL / min.

[0033] Preferably, in step two, the temperature is raised to 400-500℃ using a programmed temperature rise method, with a heating rate of 4-6℃ / min.

[0034] Preferably, in step two, the heat preservation time of the first annealing treatment is 1-2 hours.

[0035] Preferably, in step two, the temperature is raised to 700-800℃ using a programmed temperature rise method, with a heating rate of 4-6℃ / min.

[0036] Preferably, in step two, the heat preservation time for the third annealing process is 1-2 hours.

[0037] Preferably, in step two, the temperature is reduced to room temperature using a programmed cooling method, with a cooling rate of 8-12℃ / min.

[0038] Preferably, in step three, the specific operation of the cyclic tempering includes the following steps: heating the secondary treated metal film to 300°C, holding it at that temperature for 5-10 minutes, then heating it to 400°C, holding it at that temperature for 30-50 minutes, then cooling it down to 300°C, holding it at that temperature, and so on, from 300°C to 400°C and then cooling it down to 300°C to complete one cycle.

[0039] Preferably, in step three, the number of cycles of the cyclic tempering process is 3-5.

[0040] A second aspect of the present invention provides a high hydrogen flux metal membrane, which is prepared using the aforementioned high hydrogen flux metal membrane preparation process.

[0041] In summary, this invention, by selecting a suitable metal film substrate and combining it with processes such as stepwise deformation, segmented annealing, and tempering, successfully achieved grain refinement of the metal film material, resulting in a high hydrogen flux metal film. Furthermore, the metal film prepared using this invention exhibits high yield and good density. The technical solution of this invention effectively solves the problems in existing technologies for improving hydrogen flux in dense metal films, such as the difficulty in thinning the dense layer and the significant reduction in yield and density performance due to grain boundary control. Attached Figure Description

[0042] Figure 1 Scanning electron microscope (SEM) images of the high hydrogen flux metal film prepared in Example 1; wherein, A1 is a cross-sectional view and B1 is an outer surface view;

[0043] Figure 2 The images are scanning electron microscope (SEM) images of the high hydrogen flux metal film prepared in Example 2; where A2 is a cross-sectional view and B2 is an outer surface view.

[0044] Figure 3 The images shown are scanning electron microscope (SEM) images of the high hydrogen flux metal film prepared in Example 3; where A3 is a cross-sectional view and B3 is an outer surface view. Detailed Implementation

[0045] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] Example 1

[0047] This embodiment provides a high hydrogen flux metal membrane and its preparation process, as detailed below:

[0048] Step 1: Roll the NiCoFeCrMn alloy hollow fiber membrane. The diameter of the roll is 250 mm, the surface roughness Ra is 0.07 μm, the rolling speed is 1.5 m / min, and the rolling temperature is 70℃. The resulting metal membrane has a deformation treatment of 60%. When the total deformation is ≥50%, a step-by-step rolling method is used, with a single rolling deformation of 5%. After each rolling, the membrane is held at 120℃ for 40 min.

[0049] Step 2: In a hydrogen-argon mixed atmosphere with a hydrogen volume ratio of 10%, the gas flow rate is set to 400 mL / min. The deformed metal film is subjected to segmented annealing treatment. First, the temperature is increased to 480°C at a heating rate of 6°C / min and held for 1.5 h. Then, the temperature is increased to 580°C at a heating rate of 10°C / min, and held for 10 min after each heating, until the temperature reaches 580°C and is held for 10 min. Then, the temperature is increased to 750°C at a heating rate of 5°C / min and held for 1 h. Finally, the temperature is cooled to room temperature at a cooling rate of 10°C / min to obtain the secondary treated metal film.

[0050] Step 3: Heat the secondary processed metal film to 320°C, hold for 8 minutes, then heat to 400°C and hold for 40 minutes; then cool down to 320°C, repeat the above operation 4 times, and finally cool down to room temperature to obtain a high hydrogen flux metal film.

[0051] Example 2

[0052] This embodiment provides a high hydrogen flux metal membrane and its preparation process, as detailed below:

[0053] Step 1: Stretch the NiCoFeCrMn alloy tubular metal film to obtain a deformed tubular metal film with a deformation of 30%.

[0054] Step 2: In a hydrogen-argon mixed atmosphere with a hydrogen volume ratio of 10%, the gas flow rate is set to 450 mL / min. The deformed metal tubular membrane is subjected to segmented annealing treatment. First, the temperature is increased to 480°C at a heating rate of 6°C / min and held for 1.5 h. Then, the temperature is increased to 580°C at a heating rate of 10°C / min, and held for 10 min after each heating, until the temperature reaches 580°C and is held for 10 min. Then, the temperature is increased to 750°C at a heating rate of 5°C / min and held for 1 h. Finally, the temperature is cooled to room temperature at a cooling rate of 10°C / min to obtain the secondary treated metal membrane.

[0055] Step 3: Heat the secondary processed metal film to 300°C, hold for 10 minutes, then heat to 380°C and hold for 50 minutes; then cool down to 300°C, repeat the above operation 5 times, and finally cool down to room temperature to obtain a high hydrogen flux metal film.

[0056] Example 3

[0057] This embodiment provides a high hydrogen flux metal membrane and its preparation process, as detailed below:

[0058] Step 1: Roll the NiCoFeCrMn alloy hollow fiber membrane. The diameter of the roll is 250 mm, the surface roughness Ra is 0.07 μm, the rolling speed is 2 m / min, and the rolling temperature is 80℃. The resulting metal membrane has a deformation treatment of 65%. When the total deformation is ≥50%, a step-by-step rolling method is used, with a single rolling deformation of 5%. After each rolling, the membrane is held at 110℃ for 40 min.

[0059] Step 2: In a hydrogen-argon mixed atmosphere with a hydrogen volume ratio of 10%, the gas flow rate is set to 300 mL / min. The deformed metal film is subjected to segmented annealing treatment. First, the temperature is increased to 480°C at a heating rate of 6°C / min and held for 1 hour. Then, the temperature is increased to 580°C at a heating rate of 10°C / min, and held for 10 minutes after each heating, until the temperature reaches 580°C and is held for 10 minutes. Then, the temperature is increased to 750°C at a heating rate of 5°C / min and held for 1.5 hours. Finally, the temperature is reduced to room temperature at a cooling rate of 10°C / min to obtain the secondary treated metal film.

[0060] Step 3: Heat the secondary processed metal film to 320°C, hold for 8 minutes, then heat to 400°C and hold for 40 minutes; then cool down to 320°C, repeat the above operation 4 times, and finally cool down to room temperature to obtain a high hydrogen flux metal film.

[0061] Comparative Example 1

[0062] This comparative example provides a metal film and its preparation process, which differs from Example 1 in that the metal film substrate is a nickel-based alloy NiNb. 65 Other ingredients and processes remain unchanged. The details are as follows:

[0063] Step 1: NiNb 65 Alloy metal hollow fiber membranes are rolled using rolls with a diameter of 250 mm, a surface roughness Ra of 0.07 μm, a rolling speed of 1.5 m / min, and a rolling temperature of 70 °C, resulting in a deformed metal membrane with a deformation of 60%. When the total deformation is ≥50%, a step-by-step rolling method is used, with a single rolling deformation of 5%, and each rolling is followed by a heat treatment at 120 °C for 40 min.

[0064] Step 2: In a hydrogen-argon mixed atmosphere with a hydrogen volume ratio of 10%, the gas flow rate is set to 400 mL / min. The deformed metal film is subjected to segmented annealing treatment. First, the temperature is increased to 480°C at a heating rate of 6°C / min and held for 1.5 h. Then, the temperature is increased to 580°C at a heating rate of 10°C / min, and held for 10 min after each heating, until the temperature reaches 580°C and is held for 10 min. Then, the temperature is increased to 750°C at a heating rate of 5°C / min and held for 1 h. Finally, the temperature is cooled to room temperature at a cooling rate of 10°C / min to obtain the secondary treated metal film.

[0065] Step 3: Heat the secondary processed metal film to 320°C, hold for 8 minutes, then heat to 400°C and hold for 40 minutes; then cool down to 320°C, repeat the above operation 4 times, and finally cool down to room temperature to obtain a high hydrogen flux metal film.

[0066] Comparative Example 2

[0067] This comparative example provides a metal film and its preparation process. The difference from Example 1 is that the second stage of annealing is a constant temperature holding treatment, which specifically includes the following:

[0068] Step 1: Roll the NiCoFeCrMn alloy hollow fiber membrane. The diameter of the roll is 250 mm, the surface roughness Ra is 0.07 μm, the rolling speed is 1.5 m / min, and the rolling temperature is 70℃. The resulting metal membrane has a deformation treatment of 60%. When the total deformation is ≥50%, a step-by-step rolling method is used, with a single rolling deformation of 5%. After each rolling, the membrane is held at 120℃ for 40 min.

[0069] Step 2: In a hydrogen-argon mixed atmosphere with a hydrogen volume ratio of 10%, the gas flow rate is set to 400 mL / min. The deformed metal film is subjected to segmented annealing treatment. First, the temperature is increased to 480°C at a heating rate of 6°C / min and held for 1.5 h. Then, the temperature is increased to 580°C at a heating rate of 10°C / min and held for 100 min. Next, the temperature is increased to 750°C at a heating rate of 5°C / min and held for 1 h. Finally, the temperature is reduced to room temperature at a cooling rate of 10°C / min to obtain the secondary treated metal film.

[0070] Step 3: Heat the secondary processed metal film to 320°C, hold for 8 minutes, then heat to 400°C and hold for 40 minutes; then cool down to 320°C, repeat the above operation 4 times, and finally cool down to room temperature to obtain a high hydrogen flux metal film.

[0071] To further demonstrate the technical effects of the present invention, the membrane materials obtained in Examples 1-3 and Comparative Examples 1-2 were tested as follows:

[0072] Hydrogen permeation flux: The pretreated high-hydrogen-flux metal membrane is fixed in a custom hollow fiber permeation cell. The shell side of the membrane is the feed zone, and the lumen side is the permeation zone. The feed zone is connected to the H2 / He mixed gas supply pipeline, the permeation zone is connected to the N2 purge gas pipeline and the gas chromatograph inlet, and the retention zone (feed zone outlet) is also connected to the gas chromatograph inlet, forming a three-terminal detection pathway of "feed-permeation-retention".

[0073] Test parameter settings: Temperature range: 400-1000℃, set test temperature points at 100℃ intervals, and hold each temperature point for 30 minutes until the system stabilizes.

[0074] Gas parameters: H2 / He mixed gas (H2 concentrations of 10 vol.%, 50 vol.%, and 90 vol.%) is introduced into the feed side at a total flow rate of 30 mL / min; N2 purge gas is introduced into the permeate side at a flow rate of 60 mL / min; the system pressure is maintained at atmospheric pressure (0.1 MPa) to avoid damage to the membrane structure caused by high pressure.

[0075] Data acquisition and calculation: After the system stabilizes at each temperature point, the gas composition on the permeation side and the retention side is detected by gas chromatography, and the volume fractions of H2, He and N2 are recorded. At the same time, the total gas flow rate on the permeation side and the retention side is measured by soap bubble flow meter.

[0076] Yield: High-pressure nitrogen side-leak method employed;

[0077] Experimental equipment:

[0078] Gas source: High-pressure nitrogen cylinder.

[0079] Test workpiece: A prepared high-hydrogen-flux metal membrane, 25cm in length.

[0080] Module assembly: The two ends of the high hydrogen flux metal membrane are connected to the quartz tube with high-temperature resistant silicone sealant to form a complete membrane assembly. The sealant must be able to withstand temperatures up to 350°C to ensure that it will not fail in subsequent high-temperature experiments.

[0081] Pressure control: The inlet pressure is controlled by the pressure regulating valve and pressure gauge. Leak test operation steps and judgment criteria (1) Connection and pressurization: Connect the high-pressure nitrogen source to the shell side of the membrane module (i.e. the outside of the membrane), slowly adjust the pressure valve to fill the system with nitrogen, and stabilize the pressure at 0.15MPa.

[0082] (2) Detection and judgment: When nitrogen permeation test is performed at room temperature, if the membrane is completely airtight, no nitrogen permeation will be detected, and it is a finished product. If nitrogen is detected on the other side of the membrane (tube side, i.e. the inner side of the membrane), or the pressure cannot be kept stable, it proves that there is a leak in the membrane. The membrane sample cannot be used for subsequent hydrogen separation experiments. The yield of 100 membrane materials is calculated.

[0083] Grain size statistics: Statistical analysis was performed using scanning electron microscopy and a fully automated particle analysis system.

[0084] Table 1 Test Results

[0085]

[0086] The present invention also performed scanning electron microscopy tests on the high hydrogen flux metal films of Example 1 and Comparative Examples 1-2, and the results are as follows: Figure 1-3 As shown, Figure 1 Electron microscopy images of the metal film prepared in Example 1 are shown, where A1 is a cross-sectional view and B1 is an outer surface view. The images reveal a clearly refined grain structure with uniformly distributed grain sizes in the 1-2 μm range. The grain boundaries are clear and dense. This refinement effect stems from the optimized process described in the patent: stepwise deformation (such as rolling) elongates the initial grains, providing a basis for recrystallization; segmented annealing promotes uniform nucleation and growth through stepped heating, avoiding grain coarsening; and combined with cyclic tempering, further stabilizes the microstructure. Therefore, Figure 1 The fine-grained structure corresponds to high hydrogen flux and high yield, and the grain boundaries serve as a rapid hydrogen diffusion path, effectively improving the permeation performance.

[0087] Figure 2 Electron microscopy images of the high hydrogen flux metal film in Comparative Example 1 are shown. The images reveal large grain sizes (D50 = 2 μm, D90 = 3 μm) and uneven grain boundary distribution, indicating a lack of significant grain refinement. This may be due to the NiNb... 65 The substrate lacks the uniform atomic arrangement and stabilizing effect of high-entropy alloys, which may lead to local segregation or brittle phase precipitation, making it impossible for deformation and annealing processes to effectively refine the grains. As a result, the hydrogen diffusion channels are discontinuous, the throughput is low, and the yield is only 80%.

[0088] Figure 3 Electron microscopy images of the high hydrogen flux metal film in Comparative Example 2 are shown. The images reveal significantly coarse grains (D50=6μm, D90=10μm), sparse grain boundaries, and abnormally large grains. This may be because the isothermal annealing process, which involves holding the grains at a fixed temperature, causes the grains growing at that temperature to continue to grow. Small particles are engulfed by larger particles, resulting in a decrease in the number of grains and an increase in the average grain size. This leads to a decrease in the total area of ​​grain boundaries and an increase in the grain boundary spacing, manifesting as sparse grain boundaries and the formation of abnormally large grains with a volume significantly larger than the average value.

[0089] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A process for preparing a high-hydrogen-flux metal membrane, characterized in that: Includes the following steps: Step 1: Deform the metal film substrate to obtain a deformed metal film; Step 2: Under a micro-reducing atmosphere, the deformed metal film is subjected to segmented annealing treatment, wherein the temperature of the first stage of annealing treatment is 400-500℃; the temperature of the second stage of annealing treatment is 550-650℃; the temperature of the third stage of annealing treatment is 700-800℃; and then cooled to room temperature to obtain a secondary-treated metal film. Step 3: The secondary processed metal membrane is subjected to cyclic tempering at 300-400℃ to obtain a high hydrogen flux metal membrane. The raw material of the metal film substrate includes a nickel-based high-entropy alloy NiCoFeCrMn; In step two, the second stage of annealing is carried out by a staged programmable temperature rise to 550-650℃, with a heating rate of 8-12℃ / min and a holding time of 8-12min for each stage. In step three, the specific operation of the cyclic tempering includes the following steps: heating the secondary treated metal film to 300°C, holding it at that temperature for 5-10 minutes, then heating it to 400°C, holding it at that temperature for 30-50 minutes, then cooling it down to 300°C, holding it at that temperature, and then heating it from 300°C to 400°C and then cooling it down to 300°C to complete one cycle. In step three, the cyclic tempering process is repeated 3-5 times.

2. The preparation process of the high hydrogen flux metal membrane as described in claim 1, characterized in that: In step one, the deformation treatment method includes rolling, stretching, or torsion; In step one, the total deformation of the metal film substrate is 5%-65%.

3. The preparation process of the high hydrogen flux metal membrane as described in claim 2, characterized in that: The diameter of the rolling roll is 200-300 mm, and the surface roughness Ra ≤ 0.1 μm; The rolling speed is 0.5-2 m / min, and the rolling temperature is 50-80℃; In step one, when deformation treatment is carried out by rolling, if the total deformation is ≥50%, step rolling is adopted. The deformation of each rolling is 5%-10%, and after each rolling, heat preservation treatment is carried out at 100-150℃.

4. The preparation process of the high hydrogen flux metal membrane as described in claim 3, characterized in that: The heat preservation treatment time is 30-60 minutes.

5. The preparation process of the high hydrogen flux metal membrane as described in claim 1, characterized in that: In step two, the micro-reducing atmosphere is a mixture of argon and hydrogen, wherein the volume percentage of hydrogen is 5%-10%.

6. The preparation process of the high hydrogen flux metal membrane as described in claim 1, characterized in that: In step two, the temperature is raised to 400-500℃ using a programmed temperature rise method, with a heating rate of 4-6℃ / min; In step two, the holding time for the first annealing process is 1-2 hours.

7. The preparation process of the high hydrogen flux metal membrane as described in claim 1, characterized in that: In step two, the temperature is raised to 700-800℃ using a programmed temperature rise method, with a heating rate of 4-6℃ / min; In step two, the heat preservation time for the third annealing process is 1-2 hours.

8. The preparation process of the high hydrogen flux metal membrane as described in claim 1, characterized in that: In step two, the temperature is reduced to room temperature using a programmed cooling method at a rate of 8-12℃ / min.

9. A high hydrogen flux metal membrane, characterized in that: It is prepared using the high hydrogen flux metal membrane preparation process according to any one of claims 1-8.

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