Metallic diaphragm and method of manufacturing and use thereof

Abstract

The application relates to the field of diaphragm compressors, and discloses a metal diaphragm, a preparation method and application thereof. At least one surface layer of the metal diaphragm is a modified layer with a nanostructured structure and vacancy clusters. The preparation method of the metal diaphragm comprises the following steps: (1) using a projectile to spray the surface of a metal base material diaphragm, so that the obtained metal base material diaphragm has a surface nanostructured layer; and (2) using an ion beam to bombard the surface nanostructured layer of the metal base material diaphragm, so that the metal diaphragm is obtained. The metal diaphragm provided by the application has high hardness and tensile strength and excellent wear resistance, and can limit hydrogen on the surface of the diaphragm and prevent the hydrogen from diffusing into the diaphragm, thereby preventing the occurrence of hydrogen embrittlement.

Description

Technical Field

[0001] This invention relates to the field of diaphragm compressors, and more specifically to a metal diaphragm, its preparation method, and its application. Background Technology

[0002] A diaphragm compressor is a reciprocating compressor that compresses and transports gases by the reciprocating motion of a metal diaphragm within a cylinder. Due to its structure, diaphragm compressors are widely used for compressing various high-purity gases, rare and precious gases, toxic and harmful gases, and corrosive gases. Their main application areas include: energy, petrochemicals, electronics, materials science, and defense.

[0003] A metal diaphragm compressor compresses gas by deforming a diaphragm in the oil chamber through piston compression, thereby changing the volume of the gas chamber. The diaphragm is the most critical and easily damaged component in the compressor's operation. The main forms of diaphragm damage are twisting deformation, collapse, wear cracks, and mechanical fatigue. Under the pressure difference between liquid and gas, the metal diaphragm is subjected to alternating loads, resulting in flexural deformation and fatigue failure. Many factors affect diaphragm lifespan, such as the mechanical properties of the diaphragm material; poor surface smoothness; stress concentration caused by surface residues and impurities; and the fact that a thin diaphragm is prone to breakage, while an excessively thick diaphragm reduces its flexural deformation capacity.

[0004] The study on the interlayer contact mechanical behavior of metal diaphragm in diaphragm compressors (Shi Ting et al., Fluid Machinery, 2016, Vol. 44, No. 10) points out that insufficient maximum tensile stress in the slip zone of the metal diaphragm is the main cause of its failure. Meanwhile, the study on the theoretical analysis of diaphragm rupture in diaphragm compressors (Li Jiyang et al., Engineering Mechanics, 2015, Vol. 32, No. 1) also indicates that insufficient radial stress of the diaphragm is a major cause of gas rupture.

[0005] For hydrogen diaphragm compressors, the gas-side diaphragm, which comes into contact with hydrogen, is constantly exposed to a high-pressure hydrogen environment. This often leads to hydrogen embrittlement failure due to hydrogen accumulation after it seeps into the diaphragm. Solving this problem involves reducing the amount of hydrogen entering the diaphragm and slowing its propagation within the diaphragm. Current technology typically uses a coating on the diaphragm surface to prevent hydrogen from entering. However, because the diaphragm impacts and collides with the cylinder head wall during each operation, the coating, whether inorganic (e.g., ceramic) or organic (e.g., polytetrafluoroethylene), will eventually peel off over long-term use.

[0006] CN110566444A discloses a diaphragm for a diaphragm compressor and a method for improving the service life of the diaphragm. This patent describes a diaphragm fabricated by coating the surface of a substrate diaphragm with multiple coatings. While this diaphragm can prevent hydrogen from entering the interior to some extent, the coatings on the diaphragm surface will peel off during long-term use, significantly increasing the likelihood of diaphragm failure.

[0007] The paper "On the influence of heat treatment on microstructure and mechanical behavior of laser powder bed fused Inconel 718" (Schrder J, Mishurova T, Fritsch T, et al. Materials Science and Engineering A, 2021, 805, 140555.) describes the effects of different treatment temperatures and holding times on the grain size and mechanical properties of the material, but does not explain how to obtain hydrogen-resistant metallic materials through surface treatment.

[0008] Therefore, there is an urgent need to provide a metal membrane with high tensile strength and hardness, which can prevent hydrogen from entering. Summary of the Invention

[0009] The purpose of this invention is to overcome the problems in existing hydrogen diaphragm compressors, such as hydrogen embrittlement failure caused by hydrogen accumulation after permeation into the diaphragm, easy peeling of the coating on the diaphragm surface, and insufficient tensile stress of the diaphragm. This invention provides a metal diaphragm, its preparation method, and its application. The metal diaphragm has high hardness and tensile strength, excellent wear resistance, and can confine hydrogen to the diaphragm surface and prevent it from diffusing into the diaphragm, thus preventing hydrogen embrittlement.

[0010] To achieve the above objectives, the first aspect of the present invention provides a metal film, wherein at least one surface layer of the metal film is a modified layer having a nanostructure and vacancy clusters.

[0011] A second aspect of the present invention provides a method for preparing a metal film, the method comprising the following steps:

[0012] (1) The surface of the metal substrate film is sprayed with a projectile, and the resulting metal substrate film has a surface nano-layer.

[0013] (2) The surface nano-layer of the metal substrate film is bombarded with an ion beam to obtain the metal film.

[0014] A third aspect of the present invention provides a metal film prepared by the method described in the second aspect above.

[0015] The fourth aspect of the present invention provides an application of the metal diaphragm described in the first or third aspect above in a hydrogen diaphragm compressor.

[0016] Through the above technical solution, the present invention can achieve the following beneficial effects:

[0017] This invention modifies a substrate membrane using projectile blasting and ion beam bombardment, resulting in a metal membrane surface with nanostructures and vacancy clusters. The nanostructures effectively improve the wear resistance, hardness, and tensile strength of the metal membrane surface, while the vacancy clusters confine hydrogen to the membrane surface, preventing diffusion into the membrane interior and thus preventing hydrogen embrittlement. The metal membrane provided by this invention exhibits a hardness of up to 260 HB, a tensile strength of up to 880 MPa, excellent wear resistance, and effectively prevents hydrogen from entering the membrane interior. The surface hydrogen content of the metal membrane is higher than 16 ppm (by mass). Attached Figure Description

[0018] Figure 1 This is a cross-sectional SEM image of the metal film obtained in Example 1.

[0019] Figure 2 This is an EBSD cross-sectional image of the metal film prepared in Example 1.

[0020] Figure 3 This is an EBSD image of the surface of the metal film obtained in Example 1. Detailed Implementation

[0021] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0022] The first aspect of the present invention provides a metal film, wherein at least one surface layer of the metal film is a modified layer having a nanostructure and vacancy clusters.

[0023] In some embodiments of the present invention, the metal film includes a substrate and upper and lower surface layers, wherein any one or both surface layers have a nanostructure and vacancy clusters, and the substrate is stainless steel, preferably 316 stainless steel, 00Cr15Ni5 stainless steel, Hastelloy, or nickel metal alloy.

[0024] In some embodiments of the present invention, the average grain size of the metal grains in the nanostructure is 10-50 nm, which is much smaller than the size of the metal grains in the matrix (5-100 μm). This can be determined by electron backscatter diffraction (EBSD).

[0025] In this invention, the vacancy clusters refer to the pores formed between grain boundaries, distributed in the middle of the nanostructure, and the average pore size of the vacancy clusters is 20-50 nm.

[0026] In this invention, the "average aperture" of the vacancy cluster refers to the average longest distance between two points on the vacancy. It can be determined by electron backscatter diffraction (EBSD).

[0027] In some embodiments of the present invention, the thickness of the metal film is 0.3-0.5 mm; the thickness of the surface layer is 0.1-100 μm, preferably 1-60 μm.

[0028] In some embodiments of the present invention, preferably, the tensile strength of the metal diaphragm is 820-880 MPa; the hydrogen content in the surface layer of the metal diaphragm is 16-58 ppm (mass); and the hardness of the metal diaphragm is 240-260 HB. In the present invention, the hardness of the metal diaphragm refers to the surface hardness of the metal diaphragm.

[0029] In some embodiments of the present invention, the metal diaphragm is made of stainless steel, preferably 316 stainless steel, 00Cr15Ni5 stainless steel, Hastelloy, or nickel alloy.

[0030] A second aspect of the present invention provides a method for preparing a metal film, the method comprising the following steps:

[0031] (1) The surface of the metal substrate film is sprayed with a projectile, and the resulting metal substrate film has a surface nano-layer.

[0032] (2) The surface nano-layer of the metal substrate film is bombarded with an ion beam to obtain the metal film.

[0033] The inventors of this invention discovered in their research that, firstly, projectiles are used to blast the surface of a metal substrate film, which nanoscales the surface of the metal substrate film, forming a surface layer with a nanostructure. This nanostructure can effectively improve the wear resistance, hardness, and tensile strength of the metal film surface. Secondly, an ion beam is used to bombard the surface nanoscale layer of the metal substrate film, which forms vacancy clusters on the surface of the metal substrate film. These vacancy clusters can effectively prevent hydrogen from entering the interior of the film, thus preventing hydrogen embrittlement.

[0034] In some embodiments of the present invention, one or both surfaces of the metal substrate film may be modified, i.e., subjected to shot blasting and ion beam bombardment treatments. Those skilled in the art may choose according to actual needs.

[0035] In this invention, in order to make the surface of the prepared metal film have a nanostructure, a shot is used to spray the surface of the metal substrate film, and the resulting substrate film has a surface nanostructure layer.

[0036] In some embodiments of the present invention, repeatedly blasting the surface of a metal substrate film with projectiles will cause strong plastic deformation on the surface of the metal substrate film and form high-density dislocations, which will then form nanocrystals under alternating stress.

[0037] The present invention does not particularly limit the type of the metal substrate film, and can use conventional choices in the art. Preferably, the metal substrate film is selected from stainless steel substrate films, and more preferably from 316 stainless steel substrate films, 00Cr15Ni5 stainless steel substrate films, Hastelloy substrate films, or nickel metal alloy substrate films.

[0038] In some embodiments of the present invention, shot blasting can be performed in conventional shot blasting equipment, such as shot blasting machines or sandblasting machines.

[0039] In some embodiments of the present invention, the particle size of the projectile is 0.05-1.5 mm.

[0040] The present invention does not particularly limit the type of projectile, and any conventional choice in the art can be used. Preferably, the projectile is selected from glass projectiles or stainless steel projectiles.

[0041] In some embodiments of the present invention, the glass pellets are selected from SiO2 pellets, Al2O3 pellets, MgO pellets or Na2O pellets, preferably SiO2 pellets.

[0042] In some embodiments of the present invention, the stainless steel projectile is preferably a GCr15 projectile.

[0043] In some embodiments of the present invention, preferably, the spraying conditions include: a projectile velocity of 10-500 m / s, a spraying time of 10-500 min, a gas pressure carrying the projectile of 0.1 MPa-10 MPa, and a gas source of helium or nitrogen. Using this preferred method, the surface thickness of the prepared metal film can be 0.1-100 μm, and the average grain size of the surface layer grains can be 10-50 nm, effectively improving the wear resistance, hardness, and tensile strength of the prepared metal film surface.

[0044] The inventors of this invention discovered in their research that when the spraying time is too short, the surface grains do not have time to be refined and nano-sized, resulting in an excessively thin surface layer of the metal film, which affects the performance of the metal film; when the spraying time is too long, it will cause the surface stress concentration to increase, the film to warp, and affect subsequent use.

[0045] In this invention, if the velocity of the projectile is too low, the energy will be too low and the surface grains will not be refined. If the velocity of the projectile is too high, the projectile particles will be embedded in the metal surface layer, and the purpose of grain refinement will not be achieved.

[0046] In this invention, in order to make the surface layer of the prepared metal film have vacancy clusters, an ion beam is used to bombard the surface nano-layer of the metal substrate film to obtain the metal film.

[0047] In some embodiments of the present invention, the ion beam bombardment can be performed in conventional magnetron sputtering equipment, such as vapor deposition or physical deposition ion excitation equipment.

[0048] In some embodiments of the present invention, the type of ion beam can be a conventional choice in the art, as long as the particle size of the ions in the ion beam is within the range of 53.5-78 pm. Preferably, the ion beam is selected from iron ion beam or aluminum ion beam.

[0049] In some embodiments of the present invention, preferably, the bombardment conditions include: bombardment energy of 1 MeV-10 MeV, bombardment time of 1-30 min, and ion flow rate of 1 × 10⁻⁶. 14 -5×10 14 pcs / (m) 2 s), the total number of ions is 3×10 18 -5×10 18 pcs / m 2 When the bombardment conditions meet the preferred range described above, the surface of the prepared metal film can contain vacancy clusters with an average pore size of 20-50 nm, effectively blocking hydrogen from entering the interior of the metal film and preventing hydrogen embrittlement.

[0050] The inventors of this invention discovered in their research that when the bombardment energy is too low, the surface of the prepared metal film will lack vacancy clusters or have a small number of vacancy clusters, affecting the hydrogen embrittlement resistance of the metal film; when the bombardment energy is too high, it will lead to an increase in surface vacancy clusters, an increase in surface defects of the metal film, and a decrease in the mechanical properties of the metal.

[0051] A third aspect of this invention provides a metal film prepared by the method described in the second aspect above. The metal film provided by this invention has a nanostructure and vacancy clusters on its surface, and exhibits high hardness, tensile strength, and excellent wear resistance.

[0052] A fourth aspect of this invention provides the application of the metal diaphragm described in the first or third aspect above in a hydrogen diaphragm compressor. Applying the metal diaphragm obtained by this invention to a hydrogen diaphragm compressor can effectively prevent hydrogen from entering the interior of the metal diaphragm, thus preventing hydrogen embrittlement.

[0053] The present invention will be described in detail below through embodiments. In the following embodiments and comparative examples,

[0054] The morphology of the prepared metal film was characterized using scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). Specifically, the metal film was mounted on the sample preparation resin matrix and subjected to SEM and EBSD tests.

[0055] The surface thickness of the metal film was measured using SEM.

[0056] The average grain size of the surface grains and the average pore size of the vacancy clusters of the metal film were tested using EBSD.

[0057] The tensile strength, hardness, and surface hydrogen content of the prepared metal films were tested using a universal testing machine, a hardness tester, and a mass spectrometer, respectively.

[0058] Example 1

[0059] (1) A 00Cr15Ni5 stainless steel substrate film was obtained by spraying high-speed SiO2 pellets with a particle size of 0.05 mm onto the surface of the film. The surface of the 00Cr15Ni5 stainless steel substrate film was nano-sized. The pellet speed was 500 m / s, the gas pressure carrying the pellet was 10 MPa, the spraying time was 10 min, and the gas source was helium.

[0060] (2) A metal film was obtained by bombarding a nano-sized 00Cr15Ni5 stainless steel substrate film with an iron ion beam; wherein the bombardment energy was 1MeV and the ion flow rate was 1×10⁻⁶. 14 pcs / (m) 2 s), the total number of ions is 3×10 18 pcs / m 2 The bombardment time is 5 minutes.

[0061] The morphology of the prepared metal film was measured using SEM, such as... Figure 1 As shown. Figure 1 For the cross-sectional SEM image of the fabricated metal film, from Figure 1 As can be seen, the surface morphology of the metal film is completely different from that of the substrate, indicating that the surface of the metal film has been modified.

[0062] The morphology of the metal films was tested using EBSD. Figure 2 EBSD images of the prepared metal film cross-section, from Figure 2 As can be seen, the surface of the metal film has a nanostructure, and the grain size of its surface layer is significantly different from that of the substrate. Figure 3 To obtain the EBSD image of the surface of the fabricated metal film, from Figure 3 The vacancy clusters can be seen located between the nanocrystals.

[0063] Example 2

[0064] (1) High-speed SiO2 pellets with a particle size of 0.05 mm were used to spray the surface of a 00Cr15Ni5 stainless steel substrate film to obtain a nano-sized 00Cr15Ni5 stainless steel substrate film; wherein, the pellet velocity was 500 m / s, the gas pressure carrying the pellet was 10 MPa, the spraying time was 20 min, and the gas source was helium.

[0065] (2) A metal film was obtained by bombarding a nano-sized 00Cr15Ni5 stainless steel substrate film with an iron ion beam; wherein the bombardment energy was 5MeV and the ion flow rate was 1×10⁻⁶. 14 pcs / (m) 2 s), the total number of ions is 3×10 18 pcs / m 2 The bombardment time is 5 minutes.

[0066] Example 3

[0067] (1) A 00Cr15Ni5 stainless steel substrate film was obtained by spraying high-speed SiO2 pellets with a particle size of 0.05 mm onto the surface of the film. The surface of the 00Cr15Ni5 stainless steel substrate film was nano-sized. The pellet velocity was 500 m / s, the gas pressure carrying the pellet was 10 MPa, the spraying time was 300 min, and the gas source was helium.

[0068] (2) A metal film was obtained by bombarding a nano-sized 00Cr15Ni5 stainless steel substrate film with an iron ion beam; wherein the bombardment energy was 10MeV and the ion flow rate was 1×10⁻⁶. 14 pcs / (m) 2 s), the total number of ions is 5×10 18 pcs / m 2 The bombardment time is 10 minutes.

[0069] Example 4

[0070] (1) A Hastelloy substrate film with a surface nanostructure was obtained by spraying a high-speed GCr15 projectile with a particle size of 1 mm onto the surface of the film. The projectile velocity was 100 m / s, the gas pressure carrying the projectile was 5 MPa, the spraying time was 500 min, and the gas source was helium.

[0071] (2) A metal film was obtained by bombarding a nano-sized Hastelloy substrate film with an aluminum ion beam; wherein the bombardment energy was 1 MeV and the ion flow rate was 5 × 10⁻⁶. 14 pcs / (m) 2 s), the total number of ions is 3×10 18 pcs / m 2 The bombardment time is 30 minutes.

[0072] Example 5

[0073] (1) High-speed GCr15 projectiles with a particle size of 1.5 mm were used to spray the surface of Hastelloy substrate film to obtain surface nano-sized Hastelloy substrate film; wherein, the projectile velocity was 10 m / s, the gas pressure carrying the projectile was 0.1 MPa, the spraying time was 500 min, and the gas source was nitrogen.

[0074] (2) A metal film was obtained by bombarding a nano-sized Hastelloy substrate film with an aluminum ion beam; wherein the bombardment energy was 8 MeV and the ion flow rate was 3 × 10⁻⁶. 14 pcs / (m) 2 s), the total number of ions is 3×10 18 pcs / m 2 The bombardment time is 30 minutes.

[0075] Comparative Example 1

[0076] The metal film was prepared according to the method of Example 3, except that the spraying time in step (1) was 10s.

[0077] Comparative Example 2

[0078] The metal film was prepared according to the method of Example 3, except that in step (1), the spraying time was 500 min; and in step (2), the bombardment energy was 100 eV.

[0079] Test case

[0080] The surface thickness, average grain size of surface grains, and average pore size of vacancy clusters of the metal films prepared in Examples 1-5 and Comparative Examples 1-2 were measured, and the results are shown in Table 1.

[0081] The tensile strength, hardness, and surface hydrogen content of the prepared metal film were measured, and the results are shown in Table 1.

[0082] Table 1

[0083]

[0084] As can be seen from the results in Table 1, the metal film prepared by the method provided in this invention has a hardness of 240-260 HB, a tensile strength of 820-880 MPa, and a surface hydrogen content of 16-58 ppm (mass), which are significantly higher than those of the comparative example.

[0085] Furthermore, as can be seen from Example 3 and Comparative Example 1, when the spraying time is too short, the surface grains do not become refined or nano-sized, and no nano-structure is formed on the surface of the film. Although it can block hydrogen from entering the interior of the metal film, the hardness and tensile strength are significantly reduced. As can be seen from Example 3 and Comparative Example 2, when the bombardment energy of the iron ion beam is too low, it cannot effectively prevent hydrogen from entering the interior of the metal film. This is mainly because the surface layer of the prepared metal film has fewer vacancy clusters.

[0086] In summary, the surface of the metal diaphragm provided by this invention has a nanostructure and vacancy clusters. The nanostructure can effectively improve the wear resistance, hardness and tensile strength of the metal diaphragm surface; the vacancy clusters can effectively prevent hydrogen from entering the interior of the diaphragm and prevent hydrogen embrittlement.

[0087] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing a metal diaphragm, characterized in that, The method includes the following steps: (1) The surface of the metal substrate film is sprayed with a projectile, and the resulting metal substrate film has a surface nano-layer. (2) The surface nano-layer of the metal substrate film is bombarded with an ion beam to obtain the metal film; The diameter of the projectile is 0.05-1.5 mm; The conditions for the injection include: the velocity of the projectile is 10-500 m / s, the injection time is 10-500 min, the gas pressure carrying the projectile is 0.1 MPa-10 MPa, and the gas source is helium or nitrogen. The bombardment conditions include: bombardment energy of 1 MeV-10 MeV, bombardment time of 1-30 min, and ion flow rate of 1 × 10⁻⁶. 14 -5×10 14 pcs / (m) 2 s), the total number of ions is 3×10 18 -5×10 18 pcs / m 2 ; The metal substrate film is selected from stainless steel substrate film, Hastelloy substrate film or nickel metal alloy substrate film; Wherein, at least one surface layer of the metal film is a modified layer having a nanostructure and vacancy clusters; The average grain size of the metal grains in the nanostructure is 10-50 nm, and the average pore size of the vacancy clusters is 20-50 nm.

2. The method according to claim 1, wherein, The thickness of the metal film is 0.3-0.5 mm, and the thickness of the surface layer is 0.1-100 μm.

3. The method according to claim 1, wherein, The metal diaphragm has a hardness of 240-260 HB, a hydrogen content of 16-58 ppm (mass) in the surface layer of the metal diaphragm, and a tensile strength of 820-880 MPa.

4. The method according to claim 1, wherein, The particle size of the ions in the ion beam is 53.5-78 pm.

5. The method according to claim 1, wherein, The projectiles are selected from SiO2 projectiles, Al2O3 projectiles, MgO projectiles, Na2O projectiles, or GCr15 projectiles.

6. The method according to claim 5, wherein, The projectile is a SiO2 projectile.

7. The method according to claim 5, wherein, The projectile was selected from GCr15 projectiles.

8. The method according to claim 1, wherein, The ion beam is selected from either an iron ion beam or an aluminum ion beam.

9. The method according to claim 1, wherein, The stainless steel substrate film is selected from 316 stainless steel substrate film or 00Cr15Ni5 stainless steel substrate film.

10. The metal film prepared by the method according to any one of claims 1-9.

11. The application of the metal diaphragm according to claim 10 in a hydrogen diaphragm compressor.

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