Double-metal MOF-derived corrosion-resistant wave-absorbing material and preparation method thereof

Abstract

The invention belongs to the technical field of electromagnetic wave materials, and discloses a bimetallic MOF-derived corrosion-resistant wave-absorbing material and a preparation method thereof. The preparation method comprises the following steps: preparing a solution A, preparing a solution B, preparing the metal organic framework material and preparing the bimetallic MOF-derived corrosion-resistant wave-absorbing material. The material has good electromagnetic wave absorption performance and good corrosion resistance, and the corrosion-resistant current density is 1.097 * 10 <-6 > A cm <-2 >. And a wormlike structure formed by titanium-nickel-carbon effectively retards permeation of a corrosive medium by increasing the diffusion path length of a corrosive solution in the coating, and the protective capability of an interface is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electromagnetic wave materials, and in particular to a corrosion-resistant wave-absorbing material derived from a bimetallic MOF and a preparation method thereof. Background Art

[0002] Absorbing materials are widely used in stealth technology, communication equipment, and protecting personal safety and health. However, with the large-scale application of absorbing materials, their electromagnetic wave absorption performance and corrosion resistance need to be improved urgently.

[0003] Traditional absorbing materials often face the challenge of corrosion resistance. Although absorbing materials such as ferrites, carbon-based materials and conductive polymers perform well in certain applications, they still lack comprehensive performance. Ferrite materials have a high density, which may increase the weight of the device; carbon-based materials have a narrow absorption band, which limits their effectiveness in broadband applications; and although conductive polymers are light and flexible, their corrosion resistance and environmental stability are generally poor. In addition, these materials often find it difficult to simultaneously possess excellent electromagnetic wave absorption and corrosion resistance in complex environments. Therefore, the development of new materials with high-efficiency electromagnetic wave absorption and excellent corrosion resistance has become one of the hot spots and difficulties in current research. Summary of the Invention

[0004] The purpose of the present invention is to provide a bimetallic MOF-derived corrosion-resistant absorbing material and a preparation method thereof, so as to solve the problem that the existing technology cannot simultaneously take into account excellent electromagnetic wave absorption performance and corrosion resistance.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a method for preparing a bimetallic MOF-derived corrosion-resistant wave-absorbing material, comprising the following steps:

[0007] Mixing titanium precursor, methanol and acetic acid to obtain solution A;

[0008] Mix 1,4-benzenedicarboxylic acid, N,N-dimethylformamide, and nickel salt to obtain solution B;

[0009] adding solution B to solution A to obtain a mixed solution; subjecting the mixed solution to a solvothermal reaction to obtain a metal organic framework material;

[0010] The metal organic framework material is carbonized in a protective atmosphere to obtain a bimetallic MOF-derived corrosion-resistant absorbing material.

[0011] Preferably, the titanium precursor is tetrabutyl titanate or isopropyl titanate.

[0012] Preferably, the molar ratio of the titanium precursor, methanol and acetic acid is 1:0.01-0.05:0.01-0.05.

[0013] Preferably, the nickel salt is nickel acetate or nickel nitrate.

[0014] Preferably, the molar ratio of the 1,4-phthalic acid, N,N-dimethylformamide and nickel salt is 1:0.5-1:0.1-1.

[0015] Preferably, the volume ratio of solution B to solution A is 1:3-10.

[0016] Preferably, the temperature of the solvent thermal reaction is 120 to 180° C.; and the time of the solvent thermal reaction is 24 to 72 hours.

[0017] Preferably, after the solvent thermal reaction is completed, washing with N,N-dimethylformamide and methanol is performed in sequence.

[0018] Preferably, the carbonization temperature is 400-800° C.; and the carbonization time is 2-4 hours.

[0019] The present invention also provides a bimetallic MOF-derived corrosion-resistant wave-absorbing material prepared by a method for preparing the bimetallic MOF-derived corrosion-resistant wave-absorbing material.

[0020] It can be seen from the above technical solutions that compared with the prior art, the present invention has the following beneficial effects:

[0021] The corrosion-resistant absorbing material of the present invention is a composite of titanium, nickel and carbon, has a worm-like structure, enhances the magnetic loss and dielectric loss of the absorbing material, has good electromagnetic wave absorption performance, and the minimum reflection loss can reach -35dB, corresponding to an absorption bandwidth of 2GHz.

[0022] The corrosion-resistant absorbing material of the present invention, when combined with a resin to form a coating, exhibits excellent corrosion resistance. The worm-like structure formed by titanium, nickel, and carbon effectively blocks the penetration of corrosive media by increasing the diffusion path length of the corrosive solution in the coating, thereby enhancing the protective capability of the interface. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for describing the embodiments or the prior art.

[0024] Figure 1 This is an SEM image of the metal organic framework material prepared in Example 1;

[0025] Figure 2 This is the XRD pattern of the bimetallic MOF-derived corrosion-resistant absorbing material prepared in Example 1;

[0026] Figure 3 This is an SEM image of the bimetallic MOF-derived corrosion-resistant absorbing material prepared in Example 1;

[0027] Figure 4 The electromagnetic parameters of the bimetallic MOF-derived corrosion-resistant absorbing material prepared in Example 1;

[0028] Figure 5 The reflection loss of the bimetallic MOF-derived corrosion-resistant absorbing material prepared in Example 1;

[0029] Figure 6 TEM image of the bimetallic MOF-derived corrosion-resistant absorbing material prepared in Example 2;

[0030] Figure 7 Raman spectrum of the bimetallic MOF-derived corrosion-resistant absorbing material prepared in Example 2;

[0031] Figure 8 The electromagnetic parameters of the bimetallic MOF-derived corrosion-resistant absorbing material prepared in Example 2;

[0032] Figure 9 The reflection loss of the bimetallic MOF-derived corrosion-resistant absorbing material prepared in Example 2;

[0033] Figure 10 This is the Tafel curve of the bimetallic MOF-derived corrosion-resistant absorbing material prepared in Example 2. DETAILED DESCRIPTION

[0034] The present invention provides a method for preparing a bimetallic MOF-derived corrosion-resistant wave-absorbing material, comprising the following steps:

[0035] Mixing titanium precursor, methanol and acetic acid to obtain solution A;

[0036] Mix 1,4-benzenedicarboxylic acid, N,N-dimethylformamide, and nickel salt to obtain solution B;

[0037] adding solution B to solution A to obtain a mixed solution; subjecting the mixed solution to a solvothermal reaction to obtain a metal organic framework material;

[0038] The metal organic framework material is carbonized in a protective atmosphere to obtain a bimetallic MOF-derived corrosion-resistant absorbing material.

[0039] In the present invention, the titanium precursor is preferably tetrabutyl titanate or isopropyl titanate, more preferably tetrabutyl titanate. The main function of the titanium precursor is to provide a titanium metal source. Tetrabutyl titanate or isopropyl titanate are selected. They are both products currently sold on the market, such as the titanium precursor sold by Shanghai Aladdin Biochemical Technology Co., Ltd. under the trade name tetrabutyl titanate (AR, ≥99%) or isopropyl titanate (AR, ≥99%).

[0040] In the present invention, the molar ratio of the titanium precursor, methanol, and acetic acid is preferably 1:0.01-0.05:0.01-0.05, more preferably 1:0.03-0.05:0.01-0.02, and even more preferably 1:0.05:0.01. The role of methanol is to dissolve the titanium precursor. If the molar ratio of the titanium precursor to methanol is less than 1:0.01, the titanium precursor cannot be effectively dissolved; if the molar ratio of the titanium precursor to methanol is greater than 1:0.05, the metal-organic framework structure may not be formed.

[0041] In the present invention, the method for mixing the titanium precursor, methanol and acetic acid is preferably ultrasound. The ultrasound equipment used is a product currently sold on the market, such as the ultrasound equipment sold by Branson Ultrasonics (Shanghai) Co., Ltd. under the trade name Branson Ultrasonics.

[0042] In the present invention, the nickel salt is preferably nickel acetate or nickel nitrate, more preferably nickel acetate.

[0043] In the present invention, the molar ratio of 1,4-benzenedicarboxylic acid, N,N-dimethylformamide, and nickel salt is preferably 1:0.5 to 1:0.1 to 1, more preferably 1:0.8 to 1:0.2 to 0.5, and more preferably 1:1:0.3. The main function of 1,4-benzenedicarboxylic acid is to provide metal organic framework ligands, and the main function of N,N-dimethylformamide is to dissolve 1,4-benzenedicarboxylic acid and deprotonate it. If the molar ratio of 1,4-benzenedicarboxylic acid to N,N-dimethylformamide is less than 1:0.5, 1,4-benzenedicarboxylic acid cannot be effectively dissolved; if the molar ratio of 1,4-benzenedicarboxylic acid to N,N-dimethylformamide is greater than 1:1, excessive solvent is wasted, the reactant concentration is too low, and the reaction is uncontrollable. The 1,4-benzenedicarboxylic acid and N,N-dimethylformamide used in the present invention are both products currently sold on the market, such as 1,4-benzenedicarboxylic acid sold by Beijing Wokai Biotechnology Co., Ltd. under the trade name 1,4-benzenedicarboxylic acid, and N,N-dimethylformamide sold by Sinopharm Chemical Reagent Co., Ltd. under the trade name N,N-dimethylformamide (AR (Shanghai test), ≥99.5%).

[0044] In the present invention, the method for mixing 1,4-benzenedicarboxylic acid, N,N-dimethylformamide and nickel salt is: dissolving 1,4-benzenedicarboxylic acid in N,N-dimethylformamide, then adding nickel salt, and mixing using ultrasonic equipment.

[0045] In the present invention, the volume ratio of solution B to solution A is preferably 1:3-10, more preferably 1:4-8, and even more preferably 1:5.

[0046] In the present invention, the temperature of the solvent thermal reaction is preferably 120-180°C, more preferably 120-160°C, and more preferably 120°C; the time of the solvent thermal reaction is preferably 24-72 hours, more preferably 24-36 hours, and more preferably 24 hours. If the reaction temperature is lower than 120°C, the reaction temperature is too low and the reaction cannot proceed effectively; if the reaction temperature is higher than 180°C, the reaction limit of the pressure vessel is exceeded, which is prone to danger; within the reaction temperature range, if the reaction time is less than 24 hours, the reaction time is too short and the reaction is not thorough; if the reaction time is longer than 72 hours, the reaction time is too long, resulting in energy waste.

[0047] In the present invention, after the solvent thermal reaction is completed, the process further comprises cooling to room temperature, centrifuging the precipitate, washing with N,N-dimethylformamide 2 to 4 times, washing with methanol 2 to 4 times, and drying in a vacuum drying oven; the centrifugal rate is preferably 6000 r / min, and the centrifugal time is preferably 6 min; the amount ratio of the precipitate to N,N-dimethylformamide is preferably 1 g:15 to 20 mL, more preferably 1 g:17 to 20 mL, more preferably 1 g:20 mL; the amount ratio of the precipitate to methanol is preferably 1 g:15 to 20 mL, more preferably 1 g:18 to 20 mL, more preferably 1 g:20 mL; the drying temperature is preferably 60 to 100° C., more preferably 60 to 80° C., more preferably 60° C.; the drying time is preferably 22 to 26 h, more preferably 23 to 25 h, more preferably 24 h; the vacuum degree of the drying is preferably 50 to 100 Pa, more preferably 80 to 100 Pa, more preferably 100 Pa. The present invention uses a centrifuge to separate the precipitate and the reaction mother liquor after the reaction. The centrifuge is a product currently sold on the market, such as the centrifuge product sold by Hitachi under the trade name centrifuge (CF15RXII). The main function of using N,N-dimethylformamide for washing is to dissolve and remove precursors that do not participate in the reaction. Relative to 1g of precipitate, if the amount of N,N-dimethylformamide is less than 15mL, the washing is insufficient and there are too many impurities; if the amount of N,N-dimethylformamide is greater than 20mL, solvent waste is caused. The main purpose of using methanol is to exchange and wash out N,N-dimethylformamide. Relative to 1g of precipitate, if the amount of methanol is less than 15mL, the washing is insufficient; if the amount of methanol is greater than 20mL, solvent waste is caused. The purpose of vacuuming during the drying process in the vacuum drying oven is to help the volatilization of methanol.

[0048] In the present invention, the carbonization temperature is preferably 400-800°C, more preferably 450-600°C, and more preferably 500°C; the carbonization time is preferably 2-4h, more preferably 2-3h, and more preferably 2h. If the carbonization temperature is lower than 400°C, the material cannot be effectively carbonized; if the carbonization temperature is higher than 800°C, the reaction temperature is too high, the material loses its original morphology, and energy is wasted. When the carbonization temperature is within the range, if the carbonization time is less than 2h, the carbonization time is short and the reaction is incomplete; if the carbonization time is longer than 4h, the reaction time is too long, which will result in energy waste.

[0049] In the present invention, the protective atmosphere is preferably argon or nitrogen, more preferably nitrogen.

[0050] The present invention also provides a bimetallic MOF-derived corrosion-resistant wave-absorbing material prepared by a method for preparing the bimetallic MOF-derived corrosion-resistant wave-absorbing material.

[0051] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0052] Example 1

[0053] (1) Preparation of Solution A

[0054] According to the molar ratio of tetrabutyl titanate, methanol and acetic acid of 1:0.05:0.01, an ultrasonic device was used for dissolution to obtain solution A;

[0055] (2) Preparation of Solution B

[0056] 1,4-Benzenedicarboxylic acid was dissolved in N,N-dimethylformamide at a molar ratio of 1:1, and nickel acetate was then added at a molar ratio of 1:0.1. Ultrasonication was used to dissolve the solution to form a clear solution B.

[0057] (3) Preparation of metal-organic framework materials

[0058] Solution B was poured into solution A at a volume ratio of 1:5, and the mixture was stirred evenly. The mixture was then placed in a polytetrafluoroethylene-lined reactor and reacted at 120°C for 24 hours. The mixture was cooled to room temperature and centrifuged at 6000 r / min for 6 minutes to separate the precipitate. The precipitate was washed twice with N,N-dimethylformamide at a ratio of 1 g:20 mL, and then washed twice with methanol at a ratio of 1 g:20 mL. The mixture was dried in a vacuum oven at 100 Pa and 60°C for 24 hours to obtain the metal-organic framework material.

[0059] (4) Preparation of bimetallic MOF-derived corrosion-resistant absorber materials

[0060] By heating the metal organic framework material to 500°C in a tube furnace in a nitrogen atmosphere and maintaining this temperature for 2 hours, a bimetallic MOF-derived corrosion-resistant absorbing material can be obtained.

[0061] The SEM image of the metal organic framework material prepared in Example 1 is as follows: Figure 1 As shown. Figure 1 It can be seen that the prepared titanium-nickel bimetallic MOF is a hexagonal rod-like structure.

[0062] The XRD pattern and SEM image of the corrosion-resistant absorbing material derived from the bimetallic MOF prepared in Example 1 are as follows: Figure 2 、 Figure 3 shown. Figure 2 It shows that the composite material is mainly composed of anatase, rutile, metallic nickel and amorphous carbon. Figure 3 The SEM image shows the sample's microscopic morphology, which is a worm-like structure. This indicates that the titanium-nickel bimetallic MOF undergoes carbonization and cracking, transforming from the original hexagonal rod-like structure into a worm-like structure. The particles are approximately 1 μm long and 200 nm in diameter.

[0063] The electromagnetic parameters of the bimetallic MOF-derived corrosion-resistant absorbing material prepared in Example 1 were measured using a coaxial method. The results are as follows: Figure 4 As shown. Figure 4 It can be seen that the real part of the complex dielectric constant fluctuates in the range of 2.5 to 4, and the imaginary part fluctuates in the range of 0 to 0.5. The real part of the complex magnetic permeability fluctuates in the range of 0 to 1.5, and the imaginary part fluctuates in the range of 0 to 2. The composite material has certain dielectric and magnetic properties.

[0064] The reflection loss results of the corrosion-resistant absorber derived from the bimetallic MOF prepared in Example 1 are as follows: Figure 5 As shown. Figure 5 It can be seen that when the thickness is 2.35 mm, the minimum reflection loss is -38.5 dB.

[0065] Example 2

[0066] (1) Preparation of Solution A

[0067] According to the molar ratio of tetrabutyl titanate, methanol and acetic acid of 1:0.05:0.01, an ultrasonic device was used for dissolution to obtain solution A;

[0068] (2) Preparation of Solution B

[0069] 1,4-Benzenedicarboxylic acid was dissolved in N,N-dimethylformamide at a molar ratio of 1:1, and nickel acetate was then added at a molar ratio of 1:0.3. Ultrasonication was used to dissolve the solution to form a clear solution B.

[0070] (3) Preparation of metal-organic framework materials

[0071] Solution B was poured into solution A at a volume ratio of 1:5, and the mixture was stirred evenly. The mixture was then placed in a polytetrafluoroethylene-lined reactor and reacted at 120°C for 24 hours. The mixture was cooled to room temperature and centrifuged at 6000 r / min for 6 minutes to separate the precipitate. The precipitate was washed twice with N,N-dimethylformamide at a ratio of 1 g:20 mL, and then washed twice with methanol at a ratio of 1 g:20 mL. The mixture was dried in a vacuum oven at 100 Pa and 60°C for 24 hours to obtain the metal-organic framework material.

[0072] (4) Preparation of bimetallic MOF-derived corrosion-resistant absorber materials

[0073] By heating the metal organic framework material to 500°C in a tube furnace in a nitrogen atmosphere and maintaining this temperature for 2 hours, a bimetallic MOF-derived corrosion-resistant absorbing material can be obtained.

[0074] The TEM image of the corrosion-resistant absorbing material derived from the bimetallic MOF prepared in Example 2 is as follows: Figure 6 shown. Figure 6 It shows that the composite material is mainly composed of anatase, metallic nickel and amorphous carbon.

[0075] The Raman spectrum of the corrosion-resistant absorbing material derived from the bimetallic MOF prepared in Example 2 is as follows: Figure 7 As shown. Figure 7 It can be seen that the Raman spectrum shows the presence of carbon components in the material, at a wave number of about 1350cm -1 (D belt) and 1590cm -1 There are two characteristic peaks at (G band). Among them, D band is usually 3 The G band corresponds to the structural defects or disordered structure caused by hybridized carbon, while the sp 2 The in-plane vibration of the ordered graphite structure of hybrid carbon indicates that 1,4-phthalic acid undergoes carbonization during pyrolysis, forming a carbon material containing graphite and disordered carbon structures.

[0076] The electromagnetic parameters of the bimetallic MOF-derived corrosion-resistant absorbing material prepared in Example 2 were measured using the coaxial method. The results are as follows: Figure 8 As shown. Figure 8 It can be seen that the real part of the complex dielectric constant fluctuates in the range of 2.5 to 3.5, and the imaginary part fluctuates in the range of 0 to 0.5. The real part of the complex magnetic permeability fluctuates in the range of 0.25 to 1, and the imaginary part fluctuates in the range of 0 to 1, indicating that the material has good electromagnetic properties.

[0077] The reflection loss results of the corrosion-resistant absorber derived from the bimetallic MOF prepared in Example 2 are as follows: Figure 9 As shown. Figure 9It can be seen that when the thickness is 4 mm, the minimum reflection loss is -40 dB and the effective absorption bandwidth (≤10 dB) is 4.54 GHz.

[0078] The corrosion resistance of the coating was evaluated by preparing the corrosion-resistant absorbing material derived from the bimetallic MOF of Example 2: 0.1 g of the corrosion-resistant absorbing material derived from the bimetallic MOF was taken, 5 g of epoxy resin (E-44) and amine curing agent (phenolic amine-ethylenediamine of Shanghai MacLean Biochemical Technology Co., Ltd., amine value: 400-500 mgKOH / g, viscosity (25°C): 800-1300 mPa.s), the mass ratio of epoxy resin to amine curing agent was 1:2, mixed evenly, and prepared into a coating; then the coating was brushed on a 1 cm 2 The coating was coated on a Q235 steel sheet and cured at room temperature for 48 hours to obtain a coating. In NaCl solution, the Tafel curve was tested to evaluate the corrosion resistance of the coating containing the bimetallic MOF-derived corrosion-resistant absorbing material. Pure steel sheets and epoxy resin coatings (without the addition of bimetallic MOF-derived corrosion-resistant absorbing materials) were used as comparisons. The results are shown in Figure 2. Figure 10 As shown. Figure 10 It can be seen that the corrosion current density of the coating containing the bimetallic MOF-derived corrosion-resistant absorber is 1.097×10 -6 A cm -2 , indicating that the composite material has good corrosion resistance.

[0079] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing a bimetallic MOF-derived corrosion-resistant absorbing material, characterized in that: The following steps are involved: Mixing titanium precursor, methanol and acetic acid to obtain solution A; Mix 1,4-benzenedicarboxylic acid, N,N-dimethylformamide, and nickel salt to obtain solution B; adding solution B to solution A to obtain a mixed solution; subjecting the mixed solution to a solvothermal reaction to obtain a metal organic framework material; The metal organic framework material is carbonized in a protective atmosphere to obtain a bimetallic MOF-derived corrosion-resistant absorbing material.

2. The method for preparing a bimetallic MOF-derived corrosion-resistant absorbing material according to claim 1, characterized in that: The titanium precursor is tetrabutyl titanate or isopropyl titanate.

3. The method for preparing a bimetallic MOF-derived corrosion-resistant absorbing material according to claim 2, characterized in that: The molar ratio of the titanium precursor, methanol and acetic acid is 1:0.01-0.05:0.01-0.

05.

4. The method for preparing a bimetallic MOF-derived corrosion-resistant absorbing material according to claim 1 or 2, characterized in that: The nickel salt is nickel acetate or nickel nitrate.

5. The method for preparing a bimetallic MOF-derived corrosion-resistant absorbing material according to claim 3, characterized in that: The molar ratio of the 1,4-phthalic acid, N,N-dimethylformamide and nickel salt is 1:0.5-1:0.1-1.

6. The method for preparing a bimetallic MOF-derived corrosion-resistant absorbing material according to claim 5, characterized in that: The volume ratio of solution B to solution A is 1:3-10.

7. The method for preparing a bimetallic MOF-derived corrosion-resistant absorbing material according to claim 1 or 6, characterized in that: The temperature of the solvent thermal reaction is 120 to 180° C.; the time of the solvent thermal reaction is 24 to 72 hours.

8. The method for preparing a bimetallic MOF-derived corrosion-resistant absorbing material according to claim 7, characterized in that: After the solvent thermal reaction is completed, washing is performed using N,N-dimethylformamide and methanol in sequence.

9. The method for preparing a bimetallic MOF-derived corrosion-resistant absorbing material according to claim 7, characterized in that: The carbonization temperature is 400-800° C.; the carbonization time is 2-4 hours.

10. A bimetallic MOF-derived corrosion-resistant wave-absorbing material obtained by the method for preparing a bimetallic MOF-derived corrosion-resistant wave-absorbing material according to any one of claims 1 to 9.

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