A corrosion-resistant hydrogen pipeline based on a stainless steel base body and a preparation method thereof

Abstract

The application discloses a kind of based on stainless steel base's anticorrosive hydrogen pipeline and its preparation method, belong to marine industry metal material technical field.The based on stainless steel base's anticorrosive hydrogen pipeline, including stainless steel base pipe and the inner surface coating and outer surface coating being set on the stainless steel base pipe;Inner surface coating includes enamel layer, hydrogen barrier layer and transition layer in turn from inside to outside;Outer surface coating includes transition layer, first anticorrosive layer and second anticorrosive layer in turn from inside to outside;By setting inner surface coating and outer surface coating, realize the technical effect of inner hydrogen resistance outer anticorrosion;Transition layer enhances the bonding force between hydrogen barrier layer and stainless steel base, the bonding force of first anticorrosive layer and stainless steel base;Hydrogen barrier layer and enamel layer realize comprehensive hydrogen permeation resistance together;First anticorrosive layer and second anticorrosive layer act together, so that the stainless steel base submarine hydrogen pipeline can adapt to the working environment of seabed, with strong corrosion resistance.

Description

Technical Field

[0001] This application relates to a corrosion-resistant hydrogen transport pipeline based on a stainless steel matrix and its preparation method, belonging to the field of marine industry metal materials technology. Background Technology

[0002] Stainless steel is often used in high-pressure hydrogen systems due to its excellent corrosion resistance and plasticity. However, hydrogen pipelines and other equipment are in long-term service in high-pressure (1.0-4.0 MPa) hydrogen-rich environments. Hydrogen can easily penetrate into the interior of the structural materials and interact with the components and structure of the materials, leading to a decrease in mechanical properties such as strength and plasticity. This can cause cracks or brittle fractures, known as hydrogen damage, and ultimately lead to problems such as leaks. This can cause major safety accidents, resulting in casualties and economic losses.

[0003] In existing technologies, hydrogen diffusion into structural materials is typically prevented or delayed by covering the surface of the material with one or more layers of hydrogen-barrier coatings with low hydrogen permeability, while preserving the structural properties of the substrate material. However, localized damage and detachment of the hydrogen-barrier coating can easily lead to its failure. Furthermore, good adhesion between hydrogen-barrier coatings and between the coating and the substrate structural material is necessary to avoid coating detachment and other problems. Therefore, good film-substrate adhesion is also an important characteristic that hydrogen-barrier coatings must possess.

[0004] For the design of materials for submarine hydrogen pipelines, since the transportation equipment is located in the seabed environment, it is not easy to maintain and replace it frequently. Furthermore, since seawater itself has a certain degree of corrosiveness, obtaining a stainless steel matrix submarine hydrogen pipeline with high hydrogen barrier factor and strong bonding force that can adapt to the seabed environment is the prerequisite and guarantee for realizing the application of hydrogen energy. Summary of the Invention

[0005] To address the aforementioned issues, a corrosion-resistant hydrogen transport pipeline based on a stainless steel substrate and its preparation method are provided. This corrosion-resistant hydrogen transport pipeline based on a stainless steel substrate achieves the technical effect of internal hydrogen barrier and external corrosion protection by setting an inner surface coating and an outer surface coating; the enamel layer and the hydrogen barrier layer together achieve comprehensive hydrogen permeation prevention; the first anti-corrosion layer and the second anti-corrosion layer work together to enable the stainless steel substrate subsea hydrogen transport pipeline to adapt to the working environment of the seabed and have strong corrosion resistance.

[0006] According to one aspect of this application, a corrosion-resistant hydrogen transport pipeline based on a stainless steel substrate is provided, comprising a stainless steel substrate pipe and an inner surface coating and an outer surface coating disposed on the stainless steel substrate pipe. The inner surface coating comprises, from the inside out, an enamel layer, a hydrogen barrier layer, and a transition layer; the outer surface coating comprises, from the inside out, a transition layer, a first anti-corrosion layer, and a second anti-corrosion layer. The transition layer is a Ni-Ti-Ce layer; The hydrogen barrier layer is prepared from inorganic silicone adhesive, modified graphene oxide, and oxide powder. The enamel layer is prepared from SiO2, metal oxides and borax; The first anti-corrosion layer is prepared from inorganic silicone adhesive, α-Al2O3, SiO2, low-temperature glass powder and titanate coupling agent; The second anti-corrosion layer is a modified epoxy organic coating.

[0007] Specifically, the thickness of the enamel layer is not less than 50 μm; the thickness of the hydrogen barrier layer is 50~150 μm; the thickness of the transition layer is 10-15 μm; the thickness of the first anti-corrosion layer is 50~100 μm; and the thickness of the second anti-corrosion layer is 200~300 μm.

[0008] Specifically, the transition layer is a Ni-Ti-Ce layer. On the one hand, Ni and Ti have similar crystal structures and atomic radii to the stainless steel substrate, exhibiting good compatibility and forming good chemical bonds at the interface, resulting in a strong bond between the transition layer and the stainless steel substrate. On the other hand, Ni and Ti also have high chemical reactivity. Nickel and titanium can react chemically with components such as SiO2, Al2O3, and low-temperature glass powder in the hydrogen barrier layer and the first anti-corrosion layer, forming chemical bonds such as Ni-O-Si, Ti-O-Si, Ni-O, and Ti-O. Therefore, there is a strong bond between the transition layer and the hydrogen barrier layer, and between the transition layer and the first anti-corrosion layer. The transition layer enhances the bonding performance between the stainless steel substrate and the hydrogen barrier layer, and between the stainless steel substrate and the first anti-corrosion layer, making the hydrogen barrier layer and the first anti-corrosion layer firmly bonded and not easily detached.

[0009] Optionally, the oxide powder includes α-Al2O3, SiO2, low-temperature glass powder, and rare earth oxides; The mass ratio of α-Al2O3, SiO2, low-temperature glass powder, and rare earth oxides is 1:(1.2~1.5):(1~1.5):(1~1.5); Specifically, rare earth oxides include La2O3 and / or CeO2.

[0010] Preferably, the mass ratio of La2O3 to CeO2 is (5~8):1.

[0011] Specifically, in the hydrogen barrier layer, the mass of the inorganic silicone adhesive is 7 to 9 times the combined mass of α-Al2O3, SiO2, low-temperature glass powder, modified graphene oxide, and rare earth oxides.

[0012] Specifically, inorganic silica adhesives include sodium silicate, potassium silicate, or calcium silicate.

[0013] Specifically, this application specifies the proportions of each component in the hydrogen barrier layer and adds a specific proportion of modified graphene oxide and rare earth oxides to obtain a dense, stable hydrogen barrier layer with strong hydrogen barrier ability.

[0014] Specifically, both α-Al₂O₃ and SiO₂ can effectively reduce the diffusion of hydrogen molecules. The addition of SiO₂ can also promote the stability of the hydrogen barrier ceramic coating glaze. 3+ The synergistic effect of the formed aluminum-oxygen tetrahedra and silicon-oxygen tetrahedra makes the overall network structure more compact and further improves the hydrogen barrier performance. The addition of rare earth oxides can refine the grains, thereby improving stability and hydrogen barrier performance. However, the poor dispersibility of rare earth oxides and their agglomeration have an adverse effect on the performance of the hydrogen barrier layer. Adding modified graphene oxide with specific components can improve the dispersibility of rare earth oxides and obtain a hydrogen barrier layer with excellent hydrogen barrier performance.

[0015] Specifically, the mass of the inorganic silicone binder should be 7 to 9 times the sum of the masses of α-Al₂O₃, SiO₂, low-temperature glass powder, modified graphene oxide, and rare earth oxides. If there is too little inorganic silicone binder, interconnected pores are likely to exist in the coating, reducing the hydrogen permeation barrier performance of the coating and potentially leading to insufficient adhesion to the transition layer, resulting in coating peeling. If there is too much inorganic silicone binder, and the mass and proportion of α-Al₂O₃, SiO₂, low-temperature glass powder, modified graphene oxide, and rare earth oxides are too low, the hydrogen permeation barrier performance will decrease, the coating brittleness will increase, and the mechanical properties will be adversely affected.

[0016] The metal oxides include Cr2O3, Na2O, ZrO2, and Nb2O5; the mass ratio of Cr2O3, Na2O, ZrO2, and Nb2O5 is 1:(0.4~0.6):(0.3~0.5):(0.3~0.5).

[0017] Specifically, the enamel layer includes SiO2, metal oxides and borax, wherein the mass ratio of SiO2 to Cr2O3 is (1.5~2):1, and the mass ratio of borax to Cr2O3 is (0.4~0.5):1.

[0018] Optionally, the method for preparing the modified graphene oxide includes the following steps: S1. Graphene oxide is dispersed in ethanol to obtain a graphene oxide dispersion. S2. Add silane coupling agent to the graphene oxide dispersion obtained in step S1, and heat and stir. S3 centrifugation and vacuum drying yielded modified graphene oxide.

[0019] Optionally, the mass ratio of graphene oxide to ethanol is 1:(400~500); the volume fraction of the silane coupling agent is 1.1~2.1%.

[0020] Specifically, the dispersion time in step S1 is 20-30 min; the temperature in step S2 is 65-75℃ and the stirring time is 4-5 h; the centrifugation speed in step S3 is 7500-8500 rpm and the vacuum drying is 45-55℃ for 24-36 h.

[0021] Specifically, graphene oxide modified with silane coupling agents can improve the system's dispersibility and interfacial bonding.

[0022] Specifically, the silane coupling agent is an aminosilane coupling agent.

[0023] Specifically, the aminosilane coupling agent is 3-aminopropyltriethoxysilane or N-(2-aminoethyl)-3-aminopropyltrimethoxysilane.

[0024] Preferably, the aminosilane coupling agent is 3-aminopropyltriethoxysilane.

[0025] Specifically, aminosilane coupling agents can introduce amino groups onto graphene oxide, thereby improving the obtained modified graphene oxide.

[0026] Specifically, modified graphene oxide, modified by a specific method, can act as a hydrogen barrier structure and hydrogen trap, thus playing a role in preventing hydrogen accumulation. On the other hand, it helps to improve the dispersibility of rare earth oxides, prevent their aggregation, and thus enhance hydrogen barrier performance.

[0027] Optionally, by weight, the first anti-corrosion coating comprises 10-15 parts of inorganic silicone adhesive, 1.5-2 parts of α-Al2O3, 1-1.5 parts of SiO2, 0.5-1 parts of low-temperature glass powder, and 1-3 parts of titanate coupling agent.

[0028] Specifically, inorganic silica adhesives include sodium silicate, potassium silicate, or calcium silicate.

[0029] Specifically, phthalate coupling agents include isopropyltris(dioctylpyrophosphate)titanate.

[0030] Specifically, by adding a specific proportion of titanate coupling agent, isopropyl tris(dioctyl pyrophosphate) titanate can undergo a hydrolysis reaction at high temperature to generate active hydroxyl groups. On the one hand, it can generate a strong bonding force with the inorganic materials in the first anti-corrosion coating. On the other hand, it can react with the brominated epoxy resin in the second anti-corrosion coating to enhance the bonding force between the first and second anti-corrosion coatings.

[0031] Optionally, the modified epoxy organic coating comprises, by weight, 25-35 parts of brominated epoxy resin, 0.05-0.15 parts of sulfonic acid-modified graphene oxide, 0.25-0.5 parts of TiO2, 0.02-0.05 parts of polyethyleneimine, and 20-30 parts of acetone.

[0032] Specifically, the modified epoxy coating uses brominated epoxy resin. The brominated epoxy resin has high bonding strength and tighter molecular folding. The steric hindrance of the bound methyl groups effectively prevents hydrogen permeation and diffusion. A specific ratio of sulfonic acid-modified graphene oxide and TiO2 is used. The two work synergistically to give the modified epoxy coating higher hydrogen barrier performance on the one hand, and improve its corrosion resistance on the other hand, so that it can be adapted to long-term service in the seabed environment.

[0033] Specifically, the amino groups on polyethyleneimine interact with the hydroxyl groups on the TiO2 surface, giving the TiO2 surface a positive charge, and the long-chain structure of polyethyleneimine helps reduce the aggregation of TiO2; on the other hand, the interaction between polyethyleneimine and brominated epoxy resin can further improve the adhesion of the coating.

[0034] Optionally, the preparation method of the sulfonic acid-modified graphene oxide includes the following steps: S01 dissolves sodium lignosulfonate in water, adds graphene oxide, and sonicates until completely dispersed; SO2 was then refluxed under a water bath at 60-65℃ and stirred for 3-5 hours. The mixture was then washed 3-5 times each with anhydrous ethanol and deionized water by centrifugation, dried and stored to obtain sulfonic acid-modified graphene oxide.

[0035] Specifically, the mass ratio of sodium lignosulfonate to graphene oxide in SO1 is (1~2):1.

[0036] Specifically, during the modification process, sulfonic acid groups are introduced onto the surface of graphene oxide, giving it a negative charge, while TiO2 has a positive charge. This charge difference creates an electrostatic attraction between the two, which is beneficial for forming a stable composite structure, reducing direct contact between TiO2 particles, preventing agglomeration, and ensuring stable dispersion of TiO2 and sulfonic acid-modified graphene oxide. On the other hand, it also improves the interfacial compatibility between TiO2 and sulfonic acid-modified graphene oxide with brominated epoxy resin, thereby enhancing the overall performance of the coating.

[0037] According to another aspect of this application, a method for preparing the above-mentioned corrosion-resistant hydrogen transport pipeline based on a stainless steel substrate is also provided, comprising the following steps: (1) Pretreatment of stainless steel base tube: The surface of the stainless steel base tube is sandblasted, then ultrasonically cleaned in ethanol, and dried for later use. (2) Preparation of transition layer: The pretreated stainless steel substrate tube is used as the cathode and the nickel plate is used as the anode. It is placed in the electrolyte for electrodeposition to obtain Ni-Ti-Ce layer; the electrolyte includes micron titanium particles, nickel salt, cerium sulfate, complexing agent, sodium chloride, surfactant and buffer. (3) Preparation of hydrogen barrier layer: A mixture of α-Al2O3, SiO2, low temperature glass powder, modified graphene oxide and rare earth oxide is coated on the transition layer on the inner surface of stainless steel substrate tube and cured to obtain hydrogen barrier layer. (4) Preparation of enamel layer: Enamel glaze is coated on top of hydrogen barrier layer and sintered to obtain enamel layer; the enamel glaze includes SiO2, Cr2O3, Na2O, ZrO2, Nb2O5 and borax; (5) Preparation of the first anti-corrosion layer: A mixture of inorganic silicone adhesive, α-Al2O3, SiO2, low-temperature glass powder and titanate coupling agent is coated on the transition layer on the outer surface of the stainless steel base tube, cured and sintered to obtain the first anti-corrosion layer. (6) Preparation of the second anti-corrosion layer: Sulfonic acid-modified graphene oxide and TiO2 are placed in acetone, polyethyleneimine is added, ultrasonic dispersion is performed, brominated epoxy resin is added, and the mixture is stirred evenly to obtain a modified epoxy organic coating. The modified epoxy organic coating is sprayed onto the first anti-corrosion layer on the outer surface of the stainless steel substrate pipe and cured at room temperature to obtain a modified epoxy organic coating; thus, an anti-corrosion hydrogen transport pipeline based on a stainless steel substrate is obtained.

[0038] Specifically, in step (1), the stainless steel base tube is pretreated to remove surface oil and impurities, which facilitates the bonding of subsequent coatings.

[0039] Specifically, in step (2), the preparation method of the electrolyte includes: dissolving nickel salt in pure water at room temperature, adding micron-sized titanium particles, complexing agent, buffer, cerium sulfate, sodium chloride and surfactant, and stirring evenly; The nickel salt includes nickel sulfate or nickel chloride; The complexing agent is one or more of citric acid, potassium pyrophosphate, and sodium pyrophosphate; The surfactant is one or more of sodium 2-ethylhexyl sulfate, sodium dodecyl sulfate, and sodium alkylphenol polyoxyethylene ether sulfate. The buffer is boric acid.

[0040] Specifically, cerium sulfate can further improve the corrosion resistance and oxidation resistance of the transition layer, while also refining the grain structure, thereby enhancing the mechanical properties of the transition layer.

[0041] Specifically, boric acid, as a buffer, can regulate and stabilize the pH value of the electrolyte, preventing pH fluctuations from affecting the quality and process stability of the transition layer; boric acid can also inhibit hydrogen evolution and reduce porosity and defects in the transition layer.

[0042] Specifically, the preparation method of enamel glaze in step (4) includes the following steps: SiO2, Cr2O3, Na2O, ZrO2, Nb2O5 and borax are added to a ball mill according to the ratio and mixed. The mixture is placed in a heating furnace and heated to 600~620℃ and kept at that temperature for 15~20min. Then it is heated to 1100~1200℃ and kept at that temperature for 30~40min to obtain molten enamel glaze. The molten enamel glaze is quenched with water and dried to obtain a frit. The frit is ground to obtain powdered enamel glaze, and then ethanol is added to obtain enamel glaze.

[0043] Specifically, in step (6), before spraying the modified epoxy organic coating, the step of filtering the modified epoxy organic coating is also included.

[0044] Optionally, the electrodeposition temperature in step (2) is 50~60℃, and the current density is 10~50A / dm³. 2 The deposition time is 10-20 min; the electrolyte contains 70-80 g / L of micron-sized titanium particles, 0.5-0.9 mol / L of nickel salt, 0.3-0.6 g / L of cerium sulfate, 10-40 g / L of complexing agent, 0.5-2 mol / L of sodium chloride, 0.02-0.1 g / L of surfactant and 0.2-0.6 mol / L of buffer.

[0045] Optionally, in step (4), the sintering temperature is 750~850℃ and the sintering time is 5~10min; in step (5), the sintering temperature is 650~700℃ and the sintering time is 15~20min.

[0046] Specifically, after the hydrogen barrier layer is cured, an enamel glaze is applied, followed by sintering, which further enhances the bonding force between the hydrogen barrier layer and the enamel layer, forming an enamel layer and a glass-coated hydrogen barrier layer, which together achieve comprehensive hydrogen penetration prevention.

[0047] Specifically, this application specifies the sintering temperature and sintering time to obtain a dense and smooth enamel layer, a glass-coated hydrogen barrier layer, and a first anti-corrosion coating.

[0048] The beneficial effects of this application include, but are not limited to: 1. The anti-corrosion hydrogen transport pipeline based on a stainless steel substrate according to this application achieves the technical effect of internal hydrogen barrier and external corrosion protection by setting an inner surface coating and an outer surface coating; by setting a transition layer between the stainless steel substrate and the hydrogen barrier layer, and between the stainless steel substrate and the first anti-corrosion layer, the transition layer has strong bonding force with the stainless steel substrate, the hydrogen barrier layer, and the first anti-corrosion layer, thereby enhancing the bonding force between the hydrogen barrier layer and the stainless steel, and the bonding force between the first anti-corrosion layer and the stainless steel substrate; the setting of the enamel layer achieves the first-step hydrogen barrier performance; the setting of the hydrogen barrier layer makes the stainless steel substrate subsea hydrogen transport pipeline have better hydrogen barrier performance, improves the hydrogen barrier performance, and together with the enamel layer, achieves comprehensive hydrogen permeation prevention; the first anti-corrosion layer and the second anti-corrosion layer work together to enable the stainless steel substrate subsea hydrogen transport pipeline to adapt to the working environment of the seabed and have strong corrosion resistance.

[0049] 2. The anti-corrosion hydrogen transport pipeline based on stainless steel matrix according to this application specifically defines the proportions of inorganic silicone adhesive, α-Al2O3, SiO2, low-temperature glass powder, modified graphene oxide, and rare earth oxides. The resulting hydrogen barrier layer has a high hydrogen barrier factor. The preparation method of modified graphene oxide is also specified. The addition of modified graphene oxide can, on the one hand, act as a hydrogen barrier structure and hydrogen trap to block hydrogen, and on the other hand, help improve the dispersibility of rare earth oxides, avoid their agglomeration, and improve hydrogen barrier performance.

[0050] 3. According to the stainless steel-based anti-corrosion hydrogen transport pipeline of this application, the modified epoxy organic coating uses brominated epoxy resin. The brominated epoxy resin has high bonding strength, tighter molecular folding, and stronger bonding force. The use of a specific ratio of sulfonic acid-modified graphene oxide and TiO2, the two work synergistically to improve the corrosion resistance of the modified epoxy organic coating, enabling it to adapt to long-term service in the seabed environment.

[0051] 4. The preparation method of the composite coating of stainless steel substrate for submarine hydrogen transport pipeline according to this application has simple process steps, readily available raw materials, and is easy to promote and utilize. Attached Figure Description

[0052] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments of this application and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the structure of a corrosion-resistant hydrogen transport pipeline based on a stainless steel substrate, according to an embodiment of this application.

[0053] 1. Stainless steel base tube; 2. Transition layer; 3. Hydrogen barrier layer; 4. Enamel layer; 5. First anti-corrosion layer; 6. Second anti-corrosion layer. Detailed Implementation

[0054] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0055] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of skill in the art. The reagents and raw materials used in this invention are readily available through conventional means, and unless otherwise specified, they shall be used in accordance with conventional methods in the art or as per the product instructions. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to the methods of this invention. The preferred embodiments and materials described in this patent are for illustrative purposes only.

[0056] Example 1 (1) Pretreatment of stainless steel base tube: The surface of the stainless steel base tube is sandblasted, then ultrasonically cleaned in ethanol, and dried for later use. (2) Preparation of the transition layer: The pretreated stainless steel substrate tube is used as the cathode and the nickel plate is used as the anode. It is placed in the electrolyte for electrodeposition to obtain the Ni-Ti-Ce layer. The electrolyte includes 70 g / L of micron-sized titanium particles, 0.5 mol / L of nickel sulfate, 0.3 g / L of cerium sulfate, 10 g / L of citric acid complexing agent, 0.5 mol / L of sodium chloride, 0.02 g / L of sodium 2-ethylhexyl sulfate surfactant and 0.2 mol / L of boric acid buffer. The electrodeposition temperature was 50℃ and the current density was 10A / dm³. 2 The deposition time was 10 min; the thickness of the Ni-Ti-Ce layer was 10 μm. (3) Preparation of hydrogen barrier layer: A mixture of α-Al2O3, SiO2, low-temperature glass powder, modified graphene oxide and rare earth oxides was coated on the surface of a stainless steel substrate tube. The mass ratio of α-Al2O3, SiO2, low-temperature glass powder, modified graphene oxide and rare earth oxide La2O3 was 1:1.2:1:0.5:1. The mass of the inorganic silicone adhesive sodium silicate was 7 times the sum of the masses of α-Al2O3, SiO2, low-temperature glass powder, modified graphene oxide and rare earth oxides. Sintering was carried out at a temperature of 750℃ for 20 min to obtain a hydrogen barrier layer with a thickness of 150 μm. (4) Preparation of enamel layer: Enamel glaze is coated on top of hydrogen barrier layer and sintered to obtain enamel layer with a thickness of 50 μm; enamel glaze includes SiO2, Cr2O3, Na2O, ZrO2, Nb2O5 and borax; wherein the mass ratio of SiO2, Cr2O3, Na2O, ZrO2, Nb2O5 and borax is 1.5:1:0.4:0.3:0.3:0.4; sintering temperature is 750℃ and sintering time is 5 min; (5) Preparation of the first anti-corrosion layer: A mixture of 10 parts of inorganic silicone adhesive sodium silicate, 1.5 parts of α-Al2O3, 1 part of SiO2, 0.5 parts of low temperature glass powder and 1 part of titanate coupling agent isopropyltris(dioctyl pyrophosphate) titanate was coated on the transition layer on the outer surface of the stainless steel substrate tube, cured at 60°C and sintered to obtain a first anti-corrosion layer with a thickness of 50 μm, a sintering temperature of 650°C and a sintering time of 15 min; (6) Preparation of the second anti-corrosion layer: Sulfonic acid-modified graphene oxide and TiO2 are placed in acetone, polyethyleneimine is added, ultrasonic dispersion is performed, and brominated epoxy resin is added. The composition is as follows: 25 parts brominated epoxy resin, 0.05 parts sulfonic acid-modified graphene oxide, 0.25 parts TiO2, 0.02 parts polyethyleneimine and 20 parts acetone by weight. The mixture is stirred evenly to obtain a modified epoxy organic coating. The modified epoxy organic coating is sprayed onto the first anti-corrosion layer on the outer surface of the stainless steel substrate pipe and cured at room temperature to obtain a modified epoxy organic coating with a thickness of 300 μm. Thus, an anti-corrosion hydrogen transport pipeline based on a stainless steel substrate is obtained.

[0057] The preparation method of modified graphene oxide is as follows: S1. Graphene oxide was dispersed in ethanol at a mass ratio of 1:400 to obtain a graphene oxide dispersion. The dispersion time was 20 min. S2 Add 3-aminopropyltriethoxysilane to the graphene oxide dispersion obtained in step S1. The volume fraction of 3-aminopropyltriethoxysilane is 1.1%. Heat and stir at 65°C for 4 hours. S3 centrifugation and vacuum drying yielded modified graphene oxide. The centrifugation speed was 7500 rpm, and the vacuum drying was carried out at 45℃ for 24 hours.

[0058] The preparation method of enamel glaze is as follows: SiO2, Cr2O3, Na2O, ZrO2, Nb2O5 and borax were added to a ball mill according to the specified ratio and mixed. The mixture was placed in a heating furnace and heated to 600℃ and held for 15 minutes. Then it was heated to 1100℃ and held for 30 minutes to obtain molten enamel glaze. The molten enamel glaze was water-quenched and dried to obtain frit. The frit was ground to obtain powdered enamel glaze, and then ethanol was added to obtain enamel glaze.

[0059] The preparation method of sulfonic acid-modified graphene oxide is as follows: S01 dissolves sodium lignosulfonate in water, adds graphene oxide, and sonicates until completely dispersed; the mass ratio of sodium lignosulfonate to graphene oxide is 1:1. SO2 was then refluxed under a 60°C water bath and stirred for 3 hours. The mixture was then washed three times each with anhydrous ethanol and deionized water by centrifugation, dried and stored to obtain sulfonic acid-modified graphene oxide.

[0060] Example 2 (1) Pretreatment of stainless steel base tube: The surface of the stainless steel base tube is sandblasted, then ultrasonically cleaned in ethanol, and dried for later use. (2) Preparation of the transition layer: The pretreated stainless steel substrate tube is used as the cathode and the nickel plate is used as the anode. It is placed in the electrolyte for electrodeposition to obtain the Ni-Ti-Ce layer. The electrolyte includes 80 g / L of micron-sized titanium particles, 0.9 mol / L of nickel sulfate, 0.6 g / L of cerium sulfate, 40 g / L of citric acid complexing agent, 2 mol / L of sodium chloride, 0.1 g / L of sodium dodecyl sulfate surfactant and 0.6 mol / L of boric acid buffer. The electrodeposition temperature was 60℃ and the current density was 50A / dm³. 2 The deposition time was 20 min; the Ni-Ti-Ce layer thickness was 15 μm. (3) Preparation of hydrogen barrier layer: A mixture of α-Al2O3, SiO2, low-temperature glass powder, modified graphene oxide and rare earth oxide was coated on the surface of a stainless steel substrate tube. The mass ratio of α-Al2O3, SiO2, low-temperature glass powder, modified graphene oxide and rare earth oxide CeO2 was 1:1.5:1.5:0.8:1.5. The mass of the inorganic silicone adhesive calcium silicate was 9 times the sum of the masses of α-Al2O3, SiO2, low-temperature glass powder, modified graphene oxide and rare earth oxide CeO2. Sintering was carried out at a temperature of 850℃ for 30 min to obtain a hydrogen barrier layer with a thickness of 50 μm. (4) Preparation of enamel layer: Enamel glaze is coated on top of hydrogen barrier layer and sintered to obtain enamel layer with a thickness of 60 μm; enamel glaze includes SiO2, Cr2O3, Na2O, ZrO2, Nb2O5 and borax; wherein the mass ratio of SiO2, Cr2O3, Na2O, ZrO2, Nb2O5 and borax is 2:1:0.6:0.5:0.5:0.5; sintering temperature is 850℃ and sintering time is 10 min; (5) Preparation of the first anti-corrosion layer: A mixture of 15 parts of inorganic silicone adhesive calcium silicate, 2 parts of α-Al2O3, 1.5 parts of SiO2, 1 part of low-temperature glass powder and 3 parts of titanate coupling agent isopropyltris(dioctylpyrophosphoryloxy)titanate was coated on the transition layer on the outer surface of the stainless steel substrate tube, cured and sintered to obtain the first anti-corrosion layer with a thickness of 100 μm; the sintering temperature was 700℃ and the sintering time was 20 min. (6) Preparation of the second anti-corrosion layer: Sulfonic acid-modified graphene oxide and TiO2 are placed in acetone, polyethyleneimine is added, ultrasonic dispersion is performed, and brominated epoxy resin is added. According to the weight parts, it includes 35 parts of brominated epoxy resin, 0.15 parts of sulfonic acid-modified graphene oxide, 0.5 parts of TiO2, 0.05 parts of polyethyleneimine and 30 parts of acetone. The mixture is stirred evenly to obtain a modified epoxy organic coating. The modified epoxy organic coating is sprayed onto the first anti-corrosion layer on the outer surface of the stainless steel substrate pipe and cured at room temperature to obtain a modified epoxy organic coating with a thickness of 200 μm. Thus, an anti-corrosion hydrogen transport pipeline based on a stainless steel substrate is obtained.

[0061] The preparation method of modified graphene oxide is as follows: S1. Graphene oxide was dispersed in ethanol at a mass ratio of 1:500 to obtain a graphene oxide dispersion. The dispersion time was 30 min. S2. Add N-(2-aminoethyl)-3-aminopropyltrimethoxysilane to the graphene oxide dispersion obtained in step S1. The volume fraction of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane is 2.1%. Heat and stir at 75°C for 5 hours. Modified graphene oxide was obtained by centrifugation at S3 and vacuum drying at 8500 rpm and 55℃ for 36 h.

[0062] The preparation method of enamel glaze is as follows: SiO2, Cr2O3, Na2O, ZrO2, Nb2O5 and borax were added to a ball mill according to the specified ratio and mixed. The mixture was placed in a heating furnace and heated to 620℃ and held for 20 minutes. Then it was heated to 1200℃ and held for 40 minutes to obtain molten enamel glaze. The molten enamel glaze was water-quenched and dried to obtain frit. The frit was ground to obtain powdered enamel glaze, and then ethanol was added to obtain enamel glaze.

[0063] The preparation method of sulfonic acid-modified graphene oxide is as follows: S01 dissolves sodium lignosulfonate in water, adds graphene oxide, and sonicates until completely dispersed; the mass ratio of sodium lignosulfonate to graphene oxide is 2:1. SO2 was then refluxed under a 60°C water bath and stirred for 5 hours. The mixture was then washed 5 times each with anhydrous ethanol and deionized water by centrifugation, dried and stored to obtain sulfonic acid-modified graphene oxide.

[0064] Example 3 (1) Pretreatment of stainless steel base tube: The surface of the stainless steel base tube is sandblasted, then ultrasonically cleaned in ethanol, and dried for later use. (2) Preparation of the transition layer: The pretreated stainless steel substrate tube is used as the cathode and the nickel plate is used as the anode. It is placed in the electrolyte for electrodeposition to obtain the Ni-Ti-Ce layer. The electrolyte includes 80 g / L of micron-sized titanium particles, 0.7 mol / L of nickel chloride, 0.5 g / L of cerium sulfate, 20 g / L of citric acid complexing agent, 1 mol / L of sodium chloride, 0.05 g / L of sodium dodecyl sulfate surfactant and 0.4 mol / L of boric acid buffer. The electrodeposition temperature was 50℃ and the current density was 10A / dm³. 2 The deposition time was 20 min; the thickness of the Ni-Ti-Ce layer was 15 μm. (3) Preparation of hydrogen barrier layer: A mixture of α-Al2O3, SiO2, low-temperature glass powder, modified graphene oxide and rare earth oxides was coated on the surface of a stainless steel substrate tube. The mass ratio of α-Al2O3, SiO2, low-temperature glass powder, modified graphene oxide and rare earth oxides was 1:1.2:1.5:0.8:1. The rare earth oxides included La2O3 and CeO2, and the mass ratio of La2O3 and CeO2 was 5:1. The mass of the inorganic silicone adhesive sodium silicate was 8 times the sum of the masses of α-Al2O3, SiO2, low-temperature glass powder, modified graphene oxide and rare earth oxides. Sintering was carried out at 800℃ for 25 min to obtain a hydrogen barrier layer with a thickness of 100 μm. (4) Preparation of enamel layer: Enamel glaze is coated on top of hydrogen barrier layer and sintered to obtain enamel layer with a thickness of 50 μm; enamel glaze includes SiO2, Cr2O3, Na2O, ZrO2, Nb2O5 and borax; wherein the mass ratio of SiO2, Cr2O3, Na2O, ZrO2, Nb2O5 and borax is 1.5:1:0.5:0.4:0.5:0.4; sintering temperature is 800℃ and sintering time is 5 min; (5) Preparation of the first anti-corrosion layer: A mixture of 10 parts of inorganic silicone adhesive sodium silicate, 1.5 parts of α-Al2O3, 1.5 parts of SiO2, 1 part of low-temperature glass powder and 2 parts of titanate coupling agent isopropyltris(dioctyl pyrophosphate) titanate was coated on the transition layer on the outer surface of the stainless steel substrate tube, cured and sintered to obtain the first anti-corrosion layer with a thickness of 80 μm, a sintering temperature of 650℃ and a sintering time of 15 min; (4) Preparation of the second anti-corrosion layer: Sulfonic acid-modified graphene oxide and TiO2 are placed in acetone, polyethyleneimine is added, ultrasonic dispersion is performed, and brominated epoxy resin is added. According to the weight parts, it includes 30 parts of brominated epoxy resin, 0.1 parts of sulfonic acid-modified graphene oxide, 0.3 parts of TiO2, 0.03 parts of polyethyleneimine and 30 parts of acetone. The mixture is stirred evenly to obtain a modified epoxy organic coating. The modified epoxy organic coating is sprayed onto the first anti-corrosion coating on the outer surface of the stainless steel substrate pipe and cured at room temperature to obtain a modified epoxy organic coating with a thickness of 200 μm. Thus, an anti-corrosion hydrogen transport pipeline based on a stainless steel substrate is obtained.

[0065] The preparation method of modified graphene oxide is as follows: S1. Graphene oxide was dispersed in ethanol at a mass ratio of 1:450 to obtain a graphene oxide dispersion. The dispersion time was 30 min. S2. Add 3-aminopropyltriethoxysilane to the graphene oxide dispersion obtained in step S1. The volume fraction of 3-aminopropyltriethoxysilane is 1.5%. Heat and stir at 75°C for 5 hours. Modified graphene oxide was obtained by centrifugation at S3 and vacuum drying at 8500 rpm and 55℃ for 36 h.

[0066] The preparation method of sulfonic acid-modified graphene oxide is as follows: S01 dissolves sodium lignosulfonate in water, adds graphene oxide, and sonicates until completely dispersed; the mass ratio of sodium lignosulfonate to graphene oxide is 1.5:1. SO2 was then refluxed under a 60°C water bath and stirred for 3 hours. The mixture was then washed 5 times each with anhydrous ethanol and deionized water by centrifugation, dried and stored to obtain sulfonic acid-modified graphene oxide.

[0067] Example 4 The difference between Example 4 and Example 3 is that the oxide powder does not include rare earth oxides, but all other aspects are the same.

[0068] Example 5 The difference between Example 5 and Example 3 is that the rare earth oxide is Er2O3, while the rest are the same.

[0069] Example 6 The difference between Example 6 and Example 3 is that the mass ratio of La2O3 to CeO2 is 1:1, while all other aspects are the same.

[0070] Example 7 The difference between Example 7 and Example 3 is that in the preparation of modified graphene oxide, the silane coupling agent is KH560, while the rest are the same.

[0071] Example 8 The difference between Example 8 and Example 3 is that step (5) does not include a titanate coupling agent, but the rest are the same.

[0072] Example 9 The difference between Example 9 and Example 3 is that ordinary epoxy resin is used instead of non-brominated epoxy resin, while the rest are the same.

[0073] Example 10 The difference between Example 10 and Example 3 is that the sulfonic acid-modified graphene oxide is 0.4 parts and does not include TiO2, while the rest are the same.

[0074] Example 11 The difference between Example 11 and Example 3 is that 0.4 parts of TiO2 are used, excluding sulfonic acid-modified graphene oxide, while the rest are the same.

[0075] Example 12 The difference between Example 12 and Example 3 is that graphene oxide is used instead of sulfonic acid-modified graphene oxide in the second anti-corrosion layer, while the rest are the same.

[0076] Example 13 The difference between Example 13 and Example 3 is that the electrolyte does not contain cerium sulfate, but all other aspects are the same.

[0077] Comparative Example 1 The difference between Comparative Example 1 and Example 3 is that step (2) is not included, that is, neither the inner surface coating nor the outer surface coating includes a transition layer, while the rest are the same.

[0078] Comparative Example 2 The difference between Comparative Example 2 and Example 3 is that step (4) is not included, that is, the enamel layer is not included, but the rest are the same.

[0079] Comparative Example 3 The difference between Comparative Example 3 and Example 3 is that step (5) is not included, that is, the first anti-corrosion layer is not included, but the rest are the same.

[0080] Comparative Example 4 The difference between Comparative Example 4 and Example 3 is that step (3) does not include modified graphene oxide, but the rest are the same.

[0081] Comparative Example 5 The difference between Comparative Example 5 and Example 3 is that the silane-modified graphene oxide in the hydrogen barrier layer in step (3) is not modified and is graphene oxide, while the rest are the same.

[0082] Comparative Example 6 The difference between Comparative Example 6 and Example 3 is that the second anti-corrosion layer is not included, but all other aspects are the same.

[0083] Experimental Example 1. Hydrogen barrier performance test Hydrogen permeation resistance tests were conducted using a hydrogen permeation container experimental setup, and the hydrogen permeability reduction factor (PRF) was calculated. Coating density tests were performed using a coating density tester, and the test results are shown in Table 1.

[0084] Table 1 Results of hydrogen inhibition and density tests

[0085] 2. Combined strength test The bonding strength of the coating was determined by using a universal testing machine with the bonding tensile method. The test results are shown in Table 2.

[0086] Table 2 Bond Strength Test

[0087] 3. Salt spray resistance test A 3.5 wt% NaCl solution was used to simulate a seawater environment, and spray tests were conducted according to ASTM B117 to evaluate the corrosion resistance of the coating in a simulated marine atmospheric environment. In the experimental setup, the coated samples were placed in a dedicated salt spray chamber and continuously exposed to high salinity conditions at a temperature of 30–40 °C. The concentration of the 3.5 wt% NaCl solution was kept constant throughout the test, which lasted for 1000 hours to simulate the effects of long-term marine climate. The coated samples included both scratched and unscratched surfaces. The test results are shown in Table 3.

[0088] Table 3 Salt spray resistance test

[0089] According to Tables 1-3, the composite coatings obtained in Examples 1-3 have high hydrogen permeability reduction factors and high density, with the highest hydrogen permeability reduction factor being 1025 and the highest density being 99.5%. They also exhibit good salt spray resistance, meeting the requirements for long-term service in the seabed environment. Comparative Example 1, compared to Example 3, does not include a transition layer, severely affecting the hydrogen barrier performance and bonding strength of the composite coating. Comparative Example 6, compared to Example 3, shows varying degrees of decrease in hydrogen barrier performance, bonding strength, and salt spray resistance, with the greatest impact on salt spray resistance, indicating its difficulty in adapting to the seabed service environment. Examples 4-7 show a significant decrease in hydrogen barrier performance compared to Comparative Examples 1-2 and 4-5. Examples 8, 13, 1, and 3 show a significant decrease in bonding performance. Examples 10-12 show a decrease in corrosion resistance compared to Comparative Examples 3 and 6.

[0090] like Figure 1 As shown, by placing the transition layer 2 between the stainless steel substrate 1 and the hydrogen barrier layer 3, and between the stainless steel substrate 1 and the first anti-corrosion layer 5, the transition layer 2 has a strong bonding force with the stainless steel substrate 1, the hydrogen barrier layer 3, and the first anti-corrosion layer 5, thereby enhancing the bonding force between the hydrogen barrier layer 3 and the stainless steel substrate 1, and the bonding force between the first anti-corrosion layer 5 and the stainless steel substrate 1; the setting of the enamel layer 4 achieves the first-step hydrogen barrier performance; the setting of the hydrogen barrier layer 3 makes the stainless steel substrate subsea hydrogen transmission pipeline have better hydrogen barrier performance, improving the hydrogen barrier performance, and together with the enamel layer 4, achieving comprehensive hydrogen permeation prevention; the first anti-corrosion layer 5 and the second anti-corrosion layer 6 work together to enable the stainless steel substrate subsea hydrogen transmission pipeline to adapt to the working environment of the seabed and have strong corrosion resistance.

[0091] The above description is merely an embodiment of this application. Those skilled in the art will recognize that this application can have various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the technical concept and principles of this application should be included within the scope of protection of this application.

Claims

1. A corrosion-resistant hydrogen transport pipeline based on a stainless steel substrate, characterized in that, Includes a stainless steel base tube and an inner surface coating and an outer surface coating disposed on the stainless steel base tube; The inner surface coating consists of a transition layer, a hydrogen barrier layer, and an enamel layer from the stainless steel base tube outwards; the outer surface coating consists of a transition layer, a first anti-corrosion layer, and a second anti-corrosion layer from the inside out. The transition layer is a Ni-Ti-Ce layer; The hydrogen barrier layer is prepared from inorganic silicone adhesive, modified graphene oxide, and oxide powder. The enamel layer is prepared from SiO2, metal oxides and borax; The first anti-corrosion layer is prepared from inorganic silicone adhesive, α-Al2O3, SiO2, low-temperature glass powder and titanate coupling agent; The second anti-corrosion layer is a modified epoxy organic coating; The oxide powder includes α-Al2O3, SiO2, low-temperature glass powder, and rare earth oxides; The mass ratio of α-Al2O3, SiO2, low-temperature glass powder, and rare earth oxides is 1:(1.2~1.5):(1~1.5):(1~1.5); The metal oxides include Cr2O3, Na2O, ZrO2, and Nb2O5; the mass ratio of Cr2O3, Na2O, ZrO2, and Nb2O5 is 1:(0.4~0.6):(0.3~0.5):(0.3~0.5). The modified epoxy organic coating comprises, by weight, 25-35 parts of brominated epoxy resin, 0.05-0.15 parts of sulfonic acid-modified graphene oxide, 0.25-0.5 parts of TiO2, 0.02-0.05 parts of polyethyleneimine, and 20-30 parts of acetone. The preparation method of the modified graphene oxide includes the following steps: S1. Graphene oxide is dispersed in ethanol to obtain a graphene oxide dispersion. S2. Add silane coupling agent to the graphene oxide dispersion obtained in step S1, and heat and stir. S3 centrifugation and vacuum drying yielded modified graphene oxide.

2. The corrosion-resistant hydrogen transport pipeline based on a stainless steel substrate according to claim 1, characterized in that, The mass ratio of graphene oxide to ethanol is 1:(400~500); the volume fraction of silane coupling agent is 1.1~2.1%.

3. The corrosion-resistant hydrogen transport pipeline based on a stainless steel substrate according to claim 1, characterized in that, The first anti-corrosion layer comprises, by weight, 10-15 parts of inorganic silicone adhesive, 1.5-2 parts of α-Al2O3, 1-1.5 parts of SiO2, 0.5-1 parts of low-temperature glass powder, and 1-3 parts of titanate coupling agent.

4. The corrosion-resistant hydrogen transport pipeline based on a stainless steel substrate according to claim 1, characterized in that, The preparation method of the sulfonic acid-modified graphene oxide includes the following steps: S01 dissolves sodium lignosulfonate in water, adds graphene oxide, and sonicates until completely dispersed; SO2 was then refluxed in a water bath at 60-65℃ and stirred for 3-5 hours. The mixture was then washed 3-5 times each with anhydrous ethanol and deionized water by centrifugation, dried and stored to obtain sulfonic acid-modified graphene oxide.

5. A method for preparing a corrosion-resistant hydrogen transport pipeline based on a stainless steel substrate according to any one of claims 1 to 4, characterized in that, Includes the following steps: (1) Pretreatment of stainless steel base tube: The surface of the stainless steel base tube is sandblasted, then ultrasonically cleaned in ethanol, and dried for later use. (2) Preparation of transition layer: The pretreated stainless steel substrate tube is used as the cathode and the nickel plate is used as the anode. It is placed in the electrolyte for electrodeposition to obtain Ni-Ti-Ce layer; the electrolyte includes micron titanium particles, nickel salt, cerium sulfate, complexing agent, sodium chloride, surfactant and buffer. (3) Preparation of hydrogen barrier layer: A mixture of α-Al2O3, SiO2, low temperature glass powder, modified graphene oxide and rare earth oxide is coated on the transition layer on the inner surface of stainless steel substrate tube and cured to obtain hydrogen barrier layer. (4) Preparation of enamel layer: Enamel glaze is coated on top of hydrogen barrier layer and sintered to obtain enamel layer; the enamel glaze includes SiO2, Cr2O3, Na2O, ZrO2, Nb2O5 and borax; (5) Preparation of the first anti-corrosion layer: A mixture of inorganic silicone adhesive, α-Al2O3, SiO2, low-temperature glass powder and titanate coupling agent is coated on the transition layer on the outer surface of the stainless steel base tube, cured and sintered to obtain the first anti-corrosion layer. (6) Preparation of the second anti-corrosion layer: Sulfonic acid-modified graphene oxide and TiO2 are placed in acetone, polyethyleneimine is added, ultrasonic dispersion is performed, brominated epoxy resin is added, and the mixture is stirred evenly to obtain a modified epoxy organic coating. The modified epoxy organic coating is sprayed onto the first anti-corrosion layer on the outer surface of the stainless steel substrate pipe and cured at room temperature to obtain a modified epoxy organic coating; thus, an anti-corrosion hydrogen transport pipeline based on a stainless steel substrate is obtained.

6. The method for preparing a corrosion-resistant hydrogen transport pipeline based on a stainless steel substrate according to claim 5, characterized in that, Step (2) The electrodeposition temperature is 50~60℃, and the current density is 10~50A / dm³. 2 The deposition time is 10-20 min; the electrolyte contains 70-80 g / L of micron-sized titanium particles, 0.5-0.9 mol / L of nickel salt, 0.3-0.6 g / L of cerium sulfate, 10-40 g / L of complexing agent, 0.5-2 mol / L of sodium chloride, 0.02-0.1 g / L of surfactant and 0.2-0.6 mol / L of buffer.

7. The method for preparing a corrosion-resistant hydrogen transport pipeline based on a stainless steel substrate according to claim 5, characterized in that, In step (4), the sintering temperature is 750~850℃ and the sintering time is 5~10min; in step (5), the sintering temperature is 650~700℃ and the sintering time is 15~20min.

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