Composition for hydrogen-resistant coating, hydrogen-resistant coating as well as preparation method and application of hydrogen-resistant coating

Abstract

The invention relates to the field of storage and transportation of hydrogen, and discloses a composition for a hydrogen-resistant coating, the hydrogen-resistant coating as well as a preparation method and application of the hydrogen-resistant coating. The mass ratio of the modified pyrrhotite to the epoxy resin emulsion on a dry basis is 1: (2-14); the modified pyrrhotite is obtained by modifying a raw material pyrrhotite with an amino silane coupling agent. The hydrogen barrier coating prepared on the basis of the composition has higher hydrogen barrier performance and corrosion resistance.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of hydrogen storage and transportation, in particular to a composition for hydrogen barrier coating, a hydrogen barrier coating and a preparation method and application thereof. BACKGROUND

[0002] At present, the demand for clean energy is growing continuously around the world, and hydrogen energy has great development prospects in this environment. However, hydrogen transportation is an important link in the industrialization development of hydrogen energy, and hydrogen damage is a major problem that needs to be faced in the construction of hydrogen infrastructure. In the field of gas energy application, in order to achieve higher economic benefits and shorter goods transportation cycle, the mode of mixing hydrogen with natural gas and using existing natural gas pipeline for transportation has gradually become one of the best feasible solutions for large-scale and long-distance hydrogen transportation.

[0003] This method can make full use of existing infrastructure to reduce the cost of new construction and maintenance. In the process of hydrogen-doped natural gas pipeline transportation, one of the most critical and challenging problems is how to ensure the high compatibility between the pipeline material and hydrogen. Hydrogen damage to the material will reduce its ductility, fracture performance and fatigue performance, promote material degradation, reduce the service life of the material, and even cause accidents, which seriously restricts the future application and development of hydrogen energy industry.

[0004] In order to solve the problem of hydrogen damage, hydrogen barrier coating technology has emerged. Hydrogen barrier coating can slow down or prevent the permeation of hydrogen without damaging the mechanical properties of the material, thereby protecting the hydrogen damage of the metal material from the source. Among the common hydrogen barrier coatings, such as metal and metal oxide hydrogen barrier coatings, carbon / nitride hydrogen barrier coatings, etc., due to the differences in material composition elements and structure, they each have certain limitations, including but not limited to problems such as easy peeling of the coating, high cost, and complex preparation process, etc. Therefore, it is necessary to continuously explore new materials and processes to overcome these limitations.

[0005] Therefore, it is of great importance to develop a coating suitable for hydrogen transportation pipeline that takes into account resistance to hydrogen permeation and corrosion resistance and is suitable for hydrogen-rich environment, in order to ensure the safety and service life of hydrogen transportation pipeline and meet the needs of industrialization. SUMMARY

[0006] The purpose of the present application is to provide a hydrogen barrier coating with excellent hydrogen barrier performance and corrosion resistance.

[0007] In order to achieve the above-mentioned purpose, the first aspect of the present application provides a composition for hydrogen barrier coating, which contains: modified pyrrhotite, epoxy resin emulsion; the mass ratio of the modified pyrrhotite to the epoxy resin emulsion on a dry basis is 1:2-14; The modified pyrrhotite is obtained by modifying raw pyrrhotite with an amino silane coupling agent.

[0008] The second aspect of the present application provides a method for preparing a hydrogen barrier coating, which is performed by using the components in the composition of the first aspect, and the method comprises: (1) mixing the components in the composition to obtain a slurry; the composition comprises modified pyrrhotite and an epoxy resin emulsion; (2) coating and forming the slurry to obtain a hydrogen barrier coating.

[0009] The third aspect of the present application provides a hydrogen barrier coating prepared by the method of the second aspect.

[0010] The fourth aspect of the present application provides application of the hydrogen barrier coating composition of the first aspect or the hydrogen barrier coating of the third aspect in the field of hydrogen storage and transportation.

[0011] Compared with the prior art, the present application has at least the following advantages: 1. The preparation process of the present application is simple, green, low-cost and has a wide range of raw materials, and has a broad application prospect.

[0012] 2. The hydrogen barrier coating provided by the present application has obvious hydrogen barrier performance, and the hydrogen barrier coating can form a uniform barrier structure, which can prolong the hydrogen permeation path on the one hand, and the Fe-Si-O bond formed by the modified pyrrhotite and the epoxy resin can enhance the crosslinking degree of the epoxy resin, and weaken the diffusion path of hydrogen atoms in the coating.

[0013] 3. The hydrogen barrier coating provided by the present application has good adhesion between the epoxy resin-based coating and the substrate, and is not easy to fall off, and has excellent hydrogen barrier performance.

[0014] 4. In the hydrogen barrier coating provided by the present application, the modified pyrrhotite uniformly dispersed in the epoxy resin can better improve the corrosion resistance of the hydrogen barrier coating. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a process schematic diagram of preparing the hydrogen barrier coating in preparation example 1 and example 1 of the present application.

[0016] Figure 2 is an infrared spectrum of the modified pyrrhotite and the raw pyrrhotite in preparation example 1 of the present application.

[0017] Figure 3 is a Raman spectrum of the modified pyrrhotite and the raw pyrrhotite in preparation example 1 of the present application.

[0018] Figure 4Figure 1 is a micro-SEM image of the hydrogen barrier coating prepared in Example 1 and Comparative Example 1 of the present application, wherein (C2) is the result of the hydrogen barrier coating prepared in Example 1, and (C3) is the result of the hydrogen barrier coating prepared in Example 1 at a high magnification.

[0019] Figure 5 Figure 2 is a Nyquist plot of the hydrogen barrier coating prepared in Example 1 and Comparative Example 1 of the present application after immersion in a 3.5wt% NaCl solution.

[0020] Figure 6 Figure 3 is a hydrogen permeation current density plot of the hydrogen barrier coating prepared in Example 1 and Comparative Example 1 of the present application, as well as X80 steel. DETAILED DESCRIPTION

[0021] The endpoints of the ranges and any values disclosed herein are not limited to the precise values stated. The endpoints of the ranges and any values are provided as approximate descriptions of the ranges and values. The ranges and values should be construed as having a range of values including the values provided. For values that are less than one, the value is understood to be zero. For values that are greater than one, the value is understood to be one. For values that are less than zero, the value is understood to be zero. For values that are greater than zero, the value is understood to be one. For ranges provided as "between a and b," this is understood to mean "between about a and about b." The disclosure of ranges and values should be considered to have specifically disclosed the endpoints.

[0022] As previously described, the first aspect of the present application provides a hydrogen barrier coating composition, comprising: modified magnetite, an epoxy resin emulsion; the mass ratio of the modified magnetite to the epoxy resin emulsion on a dry basis is 1:2-14. The modified magnetite is obtained by modifying raw magnetite with an amino silane coupling agent.

[0023] In the present application, the "on a dry basis" means that the mass is measured based on the dry substance in the epoxy resin emulsion. For example, 100g of epoxy resin emulsion (solid content of 50wt%), the mass of the epoxy resin emulsion on a dry basis is 50g.

[0024] The inventors of the present application found in the research that the combination of modified magnetite and epoxy resin is due to the increase in the complexity of the internal channel caused by the curing network formed in the epoxy resin, which can partially prevent the movement of hydrogen, and generally exhibits good hydrogen barrier performance. The addition of magnetite can compensate for the gap between the molecular chains, and can extend the diffusion path of the corrosion medium and hydrogen. In addition, there are a large number of iron vacancies in the magnetite lattice, and the sulfur dangling bonds around the vacancies can form S-H bonds with hydrogen, and the adsorption of hydrogen provides more active sites. The combination of the two can make the coating achieve excellent corrosion resistance and hydrogen barrier performance.

[0025] The inventors of the present application have also found in research that, by using modified pyrrhotite instead of raw pyrrhotite, the organic functional groups on the surface of the pyrrhotite can be increased through covalent grafting of the modifier, so that uniform dispersion and good compatibility in the epoxy resin are achieved, thereby preparing a hydrogen barrier coating with higher hydrogen barrier performance and corrosion resistance.

[0026] Preferably, the chemical formula of the raw pyrrhotite is Fe 1-x S, wherein x is selected from any value from 0 to 0.2.

[0027] Preferably, the solid content of the epoxy resin emulsion is 40-70 wt%, for example, it can be 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt% or any value between 40-70 wt%, preferably 50-60 wt%.

[0028] According to a preferred specific embodiment, the mass ratio of the modified pyrrhotite to the epoxy resin emulsion is 1:5-20.

[0029] Preferably, the molecular weight of the raw pyrrhotite is 500-700 g / mol, and the purity is 99.9-100%.

[0030] Preferably, the amino silane coupling agent is γ-aminopropyl triethoxysilane (KH550) and / or γ-aminopropyl trimethoxysilane (KH540).

[0031] Preferably, the epoxy resin emulsion is a water-based epoxy resin emulsion and / or an oil-based epoxy resin emulsion.

[0032] Preferably, the composition further comprises a curing agent, and the curing agent is an epoxy resin curing agent.

[0033] Preferably, the curing agent is a water-based epoxy resin curing agent.

[0034] More preferably, the water-based epoxy resin curing agent is Bade Fu CA8113 and / or Bade Fu GF-G1.

[0035] The source of the curing agent is not particularly limited in the present application, and it can be self-made or a commonly commercially available product, which will not be described in detail herein.

[0036] Preferably, the mass ratio of the modified pyrrhotite, the epoxy resin emulsion on a dry basis, and the curing agent is 1:2-14:0.5-5.

[0037] Preferably, the mass ratio of the modified pyrrhotite, the epoxy resin emulsion, and the curing agent is 1:5-20:0.5-5.

[0038] Preferably, the raw pyrrhotite is prepared by using the following steps: The surfactant, the sulfur source and the iron salt are contacted in the presence of water to obtain the raw pyrrhotite. The mass ratio of the surfactant, the sulfur source and the iron salt is 1:12-14:10-12. The temperature of the contacting reaction is 100-300℃, and the time is 20-25h.

[0039] Preferably, the surfactant is at least one selected from polyvinylpyrrolidone, cetyltrimethylammonium bromide and thioacetamide.

[0040] Preferably, the sulfur source is thiourea and / or sodium sulfide.

[0041] Preferably, the iron salt is at least one selected from ferrous chloride, ferrous sulfate and ferric chloride.

[0042] The preparation method of the raw pyrrhotite can further comprise that the water, the surfactant, the sulfur source and the iron salt are stirred and mixed to obtain solution I, and then the solution I is subjected to the contacting reaction. The present application does not have any requirement for the specific operation and conditions of the stirring and mixing, as long as the surfactant, the sulfur source and the iron salt can be uniformly mixed. Those skilled in the art can select according to the known technical means in the art. Illustratively, the stirring is performed at a rotation speed of 5000-7000rpm until complete dissolution.

[0043] In some preferred embodiments, the contacting reaction is performed in a polytetrafluoroethylene-lined high-pressure reactor.

[0044] The preparation method of the raw pyrrhotite can further comprise that the solution I is subjected to oxygen removal treatment before the contacting reaction. The specific method of the oxygen removal treatment is not required, and those skilled in the art can select according to the known technical means in the art. Illustratively, the solution I is subjected to oxygen removal treatment by nitrogen bubbling.

[0045] The preparation method of the raw pyrrhotite can further comprise centrifugation, washing, drying and other conventional post-processing means in the art. Illustratively, the mixture obtained after the contacting reaction is subjected to centrifugation, washing and drying at 70-90℃ for 4-6h in sequence to obtain the raw pyrrhotite. The present application does not further describe here, and those skilled in the art should not understand it as a limitation to the present application.

[0046] The crystal structure of the pyrrhotite has monoclinic and hexagonal two types, and is also based on the superstructure of the basic crystal form of NiAs, and the pyrrhotite formed in the hydrogen sulfide corrosion process is hexagonal flaky. More preferably, the crystal morphology of the raw material pyrrhotite in the present application is hexagonal. The inventors found that under the preferred condition of adopting a hexagonal structure, compared with a monoclinic structure, the hexagonal structure is more stable, has a larger specific surface area and edge active site, and can obtain higher hydrogen barrier performance and corrosion resistance when applied to the hydrogen barrier coating of the present application.

[0047] Preferably, the modified pyrrhotite is prepared by the following operation: mixing and reacting an amino silane coupling agent with the raw material pyrrhotite in the presence of a solvent to obtain the modified pyrrhotite.

[0048] Preferably, the solvent is water and / or ethanol.

[0049] More preferably, the solvent is a mixture of water and ethanol with a mass ratio of 1:6-10.

[0050] According to a preferred embodiment, the mass ratio of the amount of the amino silane coupling agent to the raw material pyrrhotite is 10-30:1.

[0051] According to another preferred embodiment, the mixing reaction conditions include a temperature of 80-85℃ and a time of 4-8h.

[0052] Preferably, the rotation speed of the mixing reaction is 200-600rpm.

[0053] Preferably, the preparation method of the modified pyrrhotite further comprises: dispersing the amino silane coupling agent and the raw material pyrrhotite in the solvent before the mixing reaction.

[0054] The present application does not have special limitations on the specific method of the dispersion operation, as long as the amino silane coupling agent and the raw material pyrrhotite can be uniformly dispersed, and those skilled in the art can select according to the known technical means in the art. For example, an ultrasonic disperser with a power of 100-200W is used for dispersion for 10-30min, and then the obtained mixed system is subjected to the mixing reaction. The present application does not further describe here, and those skilled in the art should not understand it as a limitation of the present application.

[0055] The method of the present application can further comprise a post-treatment operation of the mixed solution obtained after the mixing reaction. The present application does not have special limitations on the specific method of the post-treatment operation, and those skilled in the art can select according to the known technical means in the art. For example, the mixed solution is sequentially subjected to suction filtration washing, drying to obtain the modified pyrrhotite.

[0056] As described above, the second aspect of the present application provides a method for preparing a hydrogen barrier coating, which is performed by using the components in the composition of the first aspect, and the method comprises: (1) mixing the components in the composition to obtain a slurry; the composition comprises modified magnetite and an epoxy resin emulsion; (2) coating the slurry to obtain a hydrogen barrier coating.

[0057] Preferably, in step (1), the composition further comprises a curing agent.

[0058] More preferably, the mixing in step (1) comprises: first mixing the modified magnetite and the epoxy resin emulsion to obtain a mixture I, and then second mixing the mixture I and the curing agent to obtain the slurry.

[0059] In the present application, the specific method of the first mixing is not particularly limited as long as the modified magnetite and the epoxy resin emulsion can be uniformly dispersed, and those skilled in the art can select according to the known technical means in the art. Illustratively, an ultrasonic disperser with a power of 100-200 W is used for dispersion for 2-7 min. Illustratively, the conditions of the first mixing include: a rotation speed of 200-400 rpm and a time of 2-7 min.

[0060] In the present application, the specific method and conditions of the second mixing are not particularly limited as long as the mixture I and the curing agent can be uniformly mixed, and those skilled in the art can select according to the known technical means in the art.

[0061] Preferably, in step (2), the coating operation comprises: placing the slurry on a substrate, using a coater to coat and curing.

[0062] Preferably, the coater is selected from at least one of a four-side film coater, a wire bar coater, and a frame coater.

[0063] Preferably, the curing conditions include: a temperature of 50-80 °C and a time of 12-36 h.

[0064] More preferably, in step (2), the thickness of the hydrogen barrier coating is 100-120 µm.

[0065] As described above, the third aspect of the present application provides a hydrogen barrier coating prepared by the method of the second aspect.

[0066] As described above, the fourth aspect of the present application provides the use of the hydrogen barrier coating composition of the first aspect or the hydrogen barrier coating of the third aspect in the field of hydrogen storage and transportation.

[0067] The application will be described in detail below by examples. When the specific experimental procedures or conditions are not specified in the following examples, the known experimental procedures described in the literature in the art can be used. When the raw materials or instruments used are not specified by the manufacturer, they can be obtained by purchase.

[0068] The raw material pyrrhotite A was prepared as follows: 70 mL of water and 0.35 g of polyvinylpyrrolidone (pvp) were weighed, and thiourea and ferrous chloride were placed in a beaker and magnetically stirred at a speed of 6000 rpm to achieve complete dissolution, obtaining solution I; The mass ratio of polyvinylpyrrolidone, thiourea and ferrous chloride was 1:13:11; The solution I was deoxygenated by nitrogen bubbling and then transferred to a polytetrafluoroethylene (PTFE) lined high-pressure reactor, which was then placed in an oven and heated to 200°C and kept for 24 h, obtaining intermediate product I; The intermediate product I was sequentially centrifuged and washed, and then placed in a vacuum drying oven at 80°C for 5 h, obtaining the raw material pyrrhotite A.

[0069] The molecular weight of the raw material pyrrhotite A was 647.43 g / mol, and the purity was 99.9%, as analyzed by scanning electron microscopy (SEM) combined with energy dispersive spectrometer (EDS) and X-ray diffractometer (XRD).

[0070] The raw material pyrrhotite B had a molecular weight of 87.91 g / mol and a purity of 99.5%, which was purchased from Shanghai Macklin Reagent Co., Ltd.

[0071] Pyrite: purchased from Shanghai Macklin Reagent Co., Ltd.

[0072] γ-Aminopropyltriethoxysilane (KH550): purchased from Shanghai Macklin Reagent Co., Ltd., CAS number 919-30-2.

[0073] γ-Glycidyl ether propyltrimethoxysilane (KH560): purchased from Shanghai Macklin Reagent Co., Ltd., CAS number 2530-83-8.

[0074] Water-based epoxy resin emulsion: solid content 57±1 wt%, purchased from Badifu Group Co., Ltd., product name MT-HY02.

[0075] Water-based epoxy resin curing agent: purchased from Badifu Group Co., Ltd., product name Badifu CA8113.

[0076] Preparation Example 1 (1) KH550 (20 g) was slowly put into a mixture of 90 mL of ethanol (17.2 mol / L) and 10 mL of deionized water, and dispersed in an ultrasonic disperser with a power of 150 W for 10 min to obtain a mixed solution I, then the raw material pyrrhotite A (Py) was dispersed in the mixed solution I, and dispersed in an ultrasonic disperser with a power of 150 W for 30 min, and then mixed at 80°C and 600 rpm for 6 h to obtain a mixed solution II; The mass ratio of KH550 to the raw material pyrrhotite A (Py) is 20:1; (2) The mixed solution II was filtered and washed with deionized water and ethanol, and dried at 60°C for 12 h to obtain a modified pyrrhotite, named K-Py.

[0077] Preparation Example 2 The method similar to Preparation Example 1 was used, except that the raw material pyrrhotite A in step (1) was replaced by an equal amount of raw material pyrrhotite B, to obtain a modified pyrrhotite, named K-Py-2.

[0078] Comparative Preparation Example 1 The method similar to Preparation Example 1 was used, except that the KH550 in step (1) was replaced by an equal amount of KH560, to obtain a modified pyrrhotite, named K-Py-D1.

[0079] Example 1 (1) 0.4 g of modified pyrrhotite (K-Py) was added to an aqueous epoxy resin emulsion, and mixed at 300 rpm for 6 min, and then dispersed in an ultrasonic disperser with a power of 150 W for 5 min, followed by adding an aqueous epoxy resin curing agent for second mixing (stirring until mixed evenly) to obtain a slurry; The mass ratio of modified pyrrhotite, epoxy resin emulsion and curing agent on a dry basis was 1:5.7:1.75; (2) The slurry was evenly placed on a steel plate, and coated using a wire bar applicator with a specification of 40 μm, and cured at 60°C for 12 h to obtain a hydrogen barrier coating.

[0080] The present application provides a process for preparing a hydrogen barrier coating. Figure 1 The process for preparing a hydrogen barrier coating of Preparation Example 1 and Example 1 is shown in the schematic diagram.

[0081] Example 2 The method similar to Example 1 was used, except that the mass of the aqueous epoxy resin emulsion on a dry basis was kept unchanged in step (1), and the mass ratio of modified pyrrhotite to aqueous epoxy resin emulsion on a dry basis was adjusted to 1:4.56 to obtain a hydrogen barrier coating.

[0082] Example 3 The method was carried out in a similar manner as in Example 1, except that the mass ratio of the modified pyrrhotite to the water-based epoxy resin emulsion on a dry basis was adjusted to 1:2.85 in step (1), and a hydrogen barrier coating was obtained.

[0083] Example 4 The method was carried out in a similar manner as in Example 1, except that the modified pyrrhotite (K-Py) in step (1) was replaced with an equal mass of modified pyrrhotite (K-Py-2), and a hydrogen barrier coating was obtained.

[0084] Comparative Example 1 The method was carried out in a similar manner as in Example 1, except that no modified pyrrhotite was added, and specifically, 4 g of water-based epoxy resin emulsion and 0.7 g of water-based epoxy resin curing agent were weighed in step (1) for the second mixing (stirring until uniformly mixed) to obtain a slurry. The remaining steps were the same as in Example 1, and a hydrogen barrier coating was obtained.

[0085] Comparative Example 2 The method was carried out in a similar manner as in Example 1, except that the modified pyrrhotite (K-Py) in step (1) was replaced with an equal mass of pyrrhotite, and a hydrogen barrier coating was obtained.

[0086] Comparative Example 3 The method was carried out in a similar manner as in Example 1, except that the modified pyrrhotite (K-Py) in step (1) was replaced with an equal mass of raw pyrrhotite A, and a hydrogen barrier coating was obtained.

[0087] Comparative Example 4 The method was carried out in a similar manner as in Example 1, except that the mass ratio of the modified pyrrhotite to the water-based epoxy resin emulsion on a dry basis was adjusted to 1:1.71 in step (1), and a hydrogen barrier coating was obtained.

[0088] Comparative Example 5 The method was carried out in a similar manner as in Example 1, except that the modified pyrrhotite (K-Py) in step (1) was replaced with an equal mass of modified pyrrhotite (K-Py-D1), and a hydrogen barrier coating was obtained.

[0089] The target thickness of the hydrogen barrier coating prepared in each of the foregoing examples and comparative examples was set to 100 μm.

[0090] Test Example 1 The modified pyrrhotite (K-Py) and the raw material pyrrhotite (Py) in the above Preparation Example 1 were tested by an infrared spectrometer (manufacturer: Bruker, model: TENSOR27), and the infrared spectrum diagram was obtained as shown in Figure 2 From the figure, it can be seen that the modified pyrrhotite mainly has the following absorption peaks: at 3650-3200 cm -1 , the stretching vibration of -OH; at 3500-3000 cm -1 , the characteristic peak of -NH; at 3000-2800 cm -1 , the stretching vibration of -CH2; at 2349 cm -1 , the infrared characteristic peak of CO2 in the air; at 2000-1700 cm -1 , the infrared characteristic peak of -CO; at 1194 cm -1 , the anti-symmetric stretching vibration and bending vibration of Si-O-Si; at 1073 cm -1 , the vibration of Fe-O-Si, and these newly added characteristic peaks prove that the KH550 has successfully modified the raw material pyrrhotite and grafted the siloxane bond on the surface.

[0091] Test Example 2 The modified pyrrhotite (K-Py) and the raw material pyrrhotite (Py) in the above Preparation Example 1 were tested by a Raman spectrometer (manufacturer: Horiba (China) Trade Co., Ltd., model: HORIBA HR-800), and the Raman spectrum diagram was obtained as shown in Figure 3 From the figure, it can be seen that the modified pyrrhotite appears new characteristic peaks, such as the Fe-O-Si bond at 1000-1200 cm -1 and the -NH at 2910-2985 cm -1 , and the appearance of these two peaks proves that the siloxane bond and the amino group in the KH550 are successfully grafted on the surface of the raw material pyrrhotite. These newly added characteristic peaks again prove that the KH550 has successfully modified the raw material pyrrhotite and grafted the siloxane bond on the surface.

[0092] Test Example 3 The hydrogen barrier coating prepared in the above examples was tested by a scanning electron microscope (manufacturer: American Phinix Limited Liability Company, model: KYKY-EM6200), and the micro-SEM diagram of the hydrogen barrier coating prepared by Example 1 and Comparative Example 1 is provided as shown in Figure 4As shown in Figure (C2), the surface of the hydrogen-barrier coating prepared in Example 1 shows obvious spherical epoxy groups, and other positions also show epoxy groups. The modified pyrrhotite is uniformly distributed in the coating. The presence of Fe-Si-O bonds increases the cross-linking degree of the epoxy coating, thereby enhancing the compatibility between the epoxy groups and pyrrhotite. As shown in Figure (C3), the distribution of pyrrhotite in the coating is more uniform compared to the unmodified state. The density of the coating is significantly higher than that of the unmodified coating. The black ferrous sulfate compound matrix is ​​uniformly dispersed on the surface, and in the microstructure, the ferrous sulfate compound also shows a certain degree of dispersion on the surface of the white spheres.

[0093] Test Example 4 1. The hydrogen barrier coating in the above example was immersed in a 3.5wt% NaCl solution for AC impedance testing (instrument: electrochemical workstation, manufacturer: Shanghai Zhenhua Instrument Co., Ltd., model: CHI660E). The oxygen barrier coating sample was used as the working electrode, the saturated calomel electrode as the reference electrode, and the platinum sheet as the counter electrode. The frequency of the electrochemical workstation was 100kHz-10mHz, the perturbation voltage was 20mV / s, and the real part impedance value was measured.

[0094] This invention provides, by way of example, Nyquist curves of the hydrogen-barrier coatings prepared in Example 1 and Comparative Example 1 after immersion in a 3.5 wt% NaCl solution, as shown below. Figure 5 As shown in the figure, "Fitting" refers to the fitting process. The figure shows that the hydrogen-barrier coating prepared in Comparative Example 1 has a local impedance of 6.5 x 10⁻⁶ at the start of immersion. 7 Ω·cm 2 Observing the Nyquist plot of the hydrogen-barrier coating prepared in Example 1, it can be found that its real impedance value during immersion is 2.3 x 10⁻⁶. 8 Ω·cm 2 The corrosion resistance of the hydrogen barrier coating is an order of magnitude higher than that of the hydrogen barrier coating in Comparative Example 1, indicating that the uniform dispersion of modified pyrrhotite in water-based epoxy resin can significantly improve the corrosion resistance of the hydrogen barrier coating.

[0095] 2. Electrochemical hydrogen permeation testing of the hydrogen-barrier coating in the above example was conducted using a Devanathan-Stachurski dual-electrolysis cell apparatus (manufacturer: Beijing Shahe Xinyue Hardware Processing Co., Ltd.). Specifically, the hydrogen-barrier coating was fixed between the hydrogen-charged end steel and the hydrogen-permeation end steel (the surfaces were pre-polished with 1500-grit sandpaper), using a three-electrode system; the hydrogen-charged solution was a mixture of 3 g / L thiourea and 0.2 mol / L NaOH solution, and the hydrogen-permeation solution was 0.2 mol / L NaOH solution; the current density was 20 mA / cm². 2and then the permeation current density was measured by using Squidstat User Interface software.

[0096] The hydrogen permeation current density diagrams of the hydrogen barrier coating prepared by Example 1 and Comparative Example 1 and X80 steel are shown in the following figure. Figure 6 As can be seen from the figure, the hydrogen permeation current density of X80 steel is the highest (16.91 μA / cm 2 ), in contrast, the hydrogen permeation current density of the hydrogen barrier coating prepared by Comparative Example 1 is (11.82 μA / cm 2 ), and the hydrogen permeation current density of the hydrogen barrier coating prepared by Example 1 is the lowest (6.17 μA / cm 2 ).

[0097] After hydrogen charging, the solid solution hydrogen volume content was measured by using a 10-point gas calibrated BRUKER G4 PHOENIX hydrogen measuring instrument (manufacturer: Bruker, model: G4 PHOENIX) heated to 900℃.

[0098] The results are shown in Table 1.

[0099] Table 1

[0100] As can be seen from the results in Table 1, the hydrogen barrier coating prepared by using the hydrogen barrier coating composition provided by the present application has higher hydrogen barrier performance and corrosion resistance. Among them, the smaller the hydrogen permeation current density, the better the hydrogen barrier performance of the coating, indicating that the hydrogen permeation speed in the coating is slower, and the hydrogen permeation is effectively inhibited; the lower the solid solution hydrogen volume content, the less hydrogen permeates into and concentrates in the specific trap area of the steel, and the stronger the hydrogen barrier performance of the coating; the hydrogen barrier coating composition provided by the present application can maximize the extension of the diffusion path of hydrogen, reduce the hydrogen permeation rate, and effectively improve the hydrogen barrier performance of the hydrogen barrier coating.

[0101] The above describes the preferred embodiments of the present application in detail, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the present application, and all fall within the protection scope of the present application.

Claims

1. A composition for a hydrogen-barrier coating, characterized in that, The composition contains: modified pyrrhotite and epoxy resin emulsion; the mass ratio of the modified pyrrhotite to the epoxy resin emulsion on a dry basis is 1:2-14; The modified pyrrhotite is obtained by modifying raw pyrrhotite with an aminosilane coupling agent.

2. The composition according to claim 1, characterized in that, The epoxy resin emulsion has a solid content of 40-70 wt%. And / or, the molecular weight of the raw material pyrrhotite is 500-700 g / mol, and the purity is 99.9-100%; And / or, the aminosilane coupling agent is γ-aminopropyltriethoxysilane and / or γ-aminopropyltrimethoxysilane; And / or, the epoxy resin emulsion is an aqueous epoxy resin emulsion and / or an oil-based epoxy resin emulsion. And / or, the composition further comprises a curing agent; The curing agent is an epoxy resin curing agent; The mass ratio of the modified pyrrhotite, the epoxy resin emulsion (on a dry basis), and the curing agent is 1:2-14:0.5-5.

3. The composition according to claim 1 or 2, characterized in that, The raw material, pyrrhotite, is prepared using the following steps: In the presence of water, a surfactant, a sulfur source, and an iron salt are reacted to obtain the raw material pyrrhotite. The mass ratio of the surfactant, the sulfur source and the iron salt is 1:12-14:10-12; The contact reaction is carried out at a temperature of 100-300℃ for 20-25 hours.

4. The composition according to claim 3, characterized in that, The surfactant is selected from at least one of polyvinylpyrrolidone, hexadecyltrimethylammonium bromide and thioacetamide; And / or, the sulfur source is thiourea and / or sodium sulfide; And / or, the iron salt is selected from at least one of ferrous chloride, ferrous sulfate and ferric chloride.

5. The composition according to claim 1 or 2, characterized in that, The modified pyrrhotite is prepared by the following steps: in the presence of a solvent, an aminosilane coupling agent is mixed and reacted with the raw material pyrrhotite to obtain the modified pyrrhotite.

6. The composition according to claim 5, characterized in that, The mass ratio of the aminosilane coupling agent to the raw material pyrrhotite is 10-30:1; And / or, the conditions for the mixed reaction include: a temperature of 80-85°C and a time of 4-8 hours.

7. A method for preparing a hydrogen-barrier coating, characterized in that, This method is performed using any of the components in the composition according to any one of claims 1-6, and the method includes: (1) The components in the composition are mixed to obtain a slurry; the composition includes modified pyrrhotite and epoxy resin emulsion; (2) The slurry is coated and molded to obtain a hydrogen barrier coating.

8. The method according to claim 7, characterized in that, In step (1), the composition further includes a curing agent; And / or, in step (2), the thickness of the hydrogen barrier coating is 100-120µm.

9. A hydrogen-barrier coating prepared by the method of claim 7 or 8.

10. The application of the hydrogen barrier coating composition according to any one of claims 1-6 or the hydrogen barrier coating according to claim 9 in the field of hydrogen storage and transportation.

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