Corrosion-resistant super-hydrophobic wave-absorbing coating and preparation method thereof

Abstract

The application belongs to the technical field of wave-absorbing materials, and particularly relates to a corrosion-resistant super-hydrophobic wave-absorbing coating and a preparation method thereof, which comprises sequentially spraying an epoxy wave-absorbing bottom layer and a fluorocarbon super-hydrophobic surface layer on a substrate, and the specific steps comprise: (1) preparation of a core-shell structure corrosion-resistant wave-absorbing agent; (2) preparation of the epoxy wave-absorbing bottom layer; (3) preparation of fluorosilane modified micro-nano hierarchical titanium dioxide powder; and (4) preparation of the fluorocarbon super-hydrophobic surface layer. The epoxy wave-absorbing bottom layer and the fluorocarbon super-hydrophobic surface layer synergistically exhibit excellent super-hydrophobic performance, and the excellent super-hydrophobic performance enables the wave-absorbing coating to have excellent corrosion resistance and self-cleaning performance. Meanwhile, the maximum loss intensity of the corrosion-resistant wave-absorbing coating of the application can reach -69.8 dB at 2-18 GHz, and the effective wave-absorbing bandwidth can reach 11.3 GHz. The application has a wide range of applications, and is suitable for being applied to various types of ships and the like in a corrosive marine environment.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of inorganic composite wave-absorbing materials, and particularly relates to a corrosion-resistant super-hydrophobic wave-absorbing coating and a preparation method thereof. BACKGROUND

[0002] Under the condition of information warfare, various advanced detection means and precise attack systems pose a great threat to the penetration and survival capability of weapon equipment. Among various military detection means, radar detection accounts for more than 60%, which is the main battlefield threat to weapon equipment. Using wave-absorbing coating to absorb and attenuate electromagnetic waves is an important means for equipment to achieve radar stealth. In actual engineering applications, not only is it required that the wave-absorbing coating has excellent wave-absorbing performance, but also is it required that the wave-absorbing coating has good corrosion resistance, especially for equipment such as ships that work in a corrosive marine environment, the corrosion resistance of the wave-absorbing coating is required to be higher.

[0003] At present, traditional wave-absorbing coatings mostly use magnetic wave-absorbing agent materials such as carbonyl iron and ferrite. Although the magnetic wave-absorbing agent materials have excellent wave-absorbing performance, they have defects such as easy oxidation and poor salt mist corrosion resistance, which limit their application in marine and other environments with high requirements for corrosion resistance. Therefore, a corrosion-resistant shell layer material is usually coated on the surface of the magnetic wave-absorbing agent to enhance the corrosion resistance of the magnetic wave-absorbing material.

[0004] Therefore, people usually composite carbon materials with magnetic wave-absorbing agents to prepare carbon-based composite wave-absorbing agents to improve the impedance matching performance of carbon materials and introduce diversified loss mechanisms to solve the above problems of single carbon material wave-absorbing agents. For example, patent CN202311017696 discloses a magnetic composite corrosion-resistant wave-absorbing material, which has a heterogeneous core-shell structure, the core is a magnetic powder, and the shell is an inorganic / organic heterogeneous shell; patent CN201911267053 discloses a preparation method of a corrosion-resistant wave-absorbing coating containing a core-shell structure type magnetic absorber, a polystyrene coated magnetic absorber is prepared by in-situ polymerization; patent CN202311018301 proposes a composite wave-absorbing and corrosion-resistant material with carbonyl iron as the core, and mesoporous SiO2 is used to coat the carbonyl iron particles to improve the corrosion resistance of the carbonyl iron particles. The above methods coat inert shell layer materials on the surface of the magnetic wave-absorbing materials to improve the corrosion resistance of the magnetic wave-absorbing materials to a certain extent, but there are still the following problems: 1. The corrosion resistance of the magnetic wave-absorbing material is limited by the simple inorganic or organic inert shell coating; 2. The shell layer materials used not only improve the corrosion resistance, but also do not have or have weak wave-absorbing performance, and the inert shell coating reduces the overall ferromagnetic performance of the material, which may weaken the magnetic loss and reduce the wave-absorbing performance; 3. The impedance matching performance of the single-layer wave-absorbing coating is poor, which limits the wave-absorbing performance of the coating; 4. These wave-absorbing coatings do not have a self-cleaning function, which is troublesome to clean, and frequent cleaning may accelerate the aging of the coating. Summary of the Invention

[0005] This invention provides a corrosion-resistant superhydrophobic microwave absorbing coating and its preparation method, in order to solve the problems of existing microwave absorbing coating technologies, such as easy corrosion in salt spray environment, unsatisfactory corrosion resistance, poor impedance matching performance, limited microwave absorption performance, lack of self-cleaning function, troublesome cleaning, and poor compatibility between microwave absorption performance and corrosion resistance.

[0006] To achieve the objectives of this invention, a method for preparing a corrosion-resistant superhydrophobic microwave absorbing coating is provided, comprising the following steps:

[0007] (1) Preparation of core-shell structure corrosion-resistant microwave absorbing agent: First, magnetic microwave absorbing particles are added to titanium dioxide sol and stirred, collected, washed and dried to obtain core-shell structure powder of titanium dioxide coated magnetic microwave absorbing particles; then the core-shell structure powder is heat-treated at 400~550℃ for 2~6 hours in hydrogen atmosphere to obtain composite microwave absorbing agent powder; finally, the composite microwave absorbing agent is uniformly dispersed in anhydrous ethanol / water mixed solution, and titanium tetrabutyl ester, ammonia and fluorosilane are added in sequence, stirred and collected and dried to obtain core-shell structure microwave absorbing agent powder with superhydrophobic properties;

[0008] (2) Preparation of epoxy microwave absorbing substrate: After diluting the epoxy resin with a diluent, add the core-shell structure microwave absorbing agent powder, stir at high speed to make it evenly mixed, add the epoxy curing agent, continue stirring, and then spray it on the substrate and cure to obtain the epoxy microwave absorbing substrate;

[0009] (3) Preparation of fluorosilane-modified micro-nano graded titanium dioxide powder: First, micron-sized and nano-sized titanium dioxide powders are uniformly mixed, and then heat-treated at 400-450℃ for 2-4 hours in a hydrogen atmosphere to obtain hydrogenated micro-nano graded titanium dioxide powder; finally, the hydrogenated micro-nano graded titanium dioxide powder is uniformly dispersed in anhydrous ethanol / water mixed solution, and tetraethyl orthosilicate, organosilicon hydrophobic agent and fluorosilane are added in sequence, stirred for 1-3 hours, collected by centrifugation, and dried at 60℃ for 48 hours to obtain fluorosilane-modified micro-nano graded titanium dioxide powder;

[0010] (4) Preparation of fluorocarbon superhydrophobic surface layer: First, dilute the fluorocarbon resin with a diluent, then add fluorosilane-modified micro-nano graded titanium dioxide powder, stir with a high-speed mixer to make it evenly mixed, then add fluorocarbon curing agent, continue stirring, then spray it on the epoxy microwave absorbing substrate, dry at room temperature, the fluorocarbon superhydrophobic surface layer is cured, and a corrosion-resistant superhydrophobic microwave absorbing coating is obtained.

[0011] Furthermore, the thickness of the aforementioned fluorocarbon superhydrophobic surface layer is 0.1~1mm; the thickness of the epoxy microwave absorbing bottom layer is 0.8~3mm.

[0012] Further, in the step (1) of the preparation of the core-shell structure powder, the mass ratio of the magnetic wave-absorbing particles to the titanium dioxide sol is 1:4-1:10; in the preparation of the core-shell structure wave-absorbing agent powder, the mass ratio of the anhydrous ethanol / water mixed solution, the composite wave-absorbing agent, butyl titanate, ammonia water and fluorosilane is 500:10-20:1-1.5:0.3-2:5-8.

[0013] Further, in the step (1) of the preparation of the core-shell structure powder, the mass ratio of the magnetic wave-absorbing particles to the titanium dioxide sol is 1:4-1:10; in the preparation of the core-shell structure wave-absorbing agent powder, the mass ratio of the anhydrous ethanol / water mixed solution, the composite wave-absorbing agent, butyl titanate, ammonia water and fluorosilane is 500:10-20:1-1.5:0.3-2:5-8.

[0014] Further, in the step (2), the mass ratio of the epoxy resin to the epoxy curing agent is controlled to be 10:1-10:3, the mass ratio of the epoxy resin to the diluent is controlled to be 11:1-5:1, and the mass ratio of the epoxy resin to the core-shell structure corrosion-resistant wave-absorbing agent powder is controlled to be 1:3-2:1.

[0015] Further, in the step (3), the crystal phase structure of the titanium dioxide powder is one of anatase phase, rutile phase or mixed crystal of the two, the particle size of the micron-level titanium dioxide powder is 1-3 um, the particle size of the nano-level titanium dioxide powder is 5-30 nm, and the mass ratio of the micron-level titanium dioxide powder to the nano-level titanium dioxide powder is 1:1-1:4.

[0016] Further, in the step (3), the mass ratio of the anhydrous ethanol / water to the micro-nano hierarchical titanium dioxide powder is controlled to be 50:1-50:3, the mass ratio of the micro-nano hierarchical titanium dioxide powder to the tetraethyl orthosilicate is 12:1-10:1, the mass ratio of the organic silicon hydrophobic agent to the fluorosilane is 3:4-3:5, and the mass ratio of the micro-nano hierarchical titanium dioxide powder to the fluorosilane is 3:1-2:1.

[0017] Further, in the step (4), the mass ratio of the fluorocarbon resin to the fluorocarbon curing agent is controlled to be 5:1-7:1, the mass ratio of the fluorocarbon resin to the diluent is 5:1-4:1, and the mass ratio of the fluorocarbon resin to the fluorosilane modified micro-nano hierarchical titanium dioxide powder is controlled to be 5:1-1:1.

[0018] Further, in the step (1), the fluorosilane is perfluorodecyltrimethoxysilane, perfluorodecyltriethoxysilane, perfluorodecyltrichlorosilane or perfluorooctyltrichlorosilane.

[0019] Further, the preparation method prepares a kind of corrosion-resistant super-hydrophobic wave-absorbing coating.

[0020] Compared with the prior art, the present application has the following beneficial effects:

[0021] 1、The present application adopts hydrogenation and fluorosilane modification of micro-nano hierarchical titanium dioxide powder and strong hydrophobic fluorocarbon resin to construct a fluorocarbon super-hydrophobic surface layer, (1) hydrogenation treatment enhances the dielectric properties of titanium dioxide powder and improves the wave absorption performance, in addition, by controlling the hydrogenation treatment time, the dielectric properties of titanium dioxide can be controlled to have better impedance matching characteristics, (2) the micro-nano hierarchical titanium dioxide powder treated by fluorosilane can not only construct a better surface rough structure on the super-hydrophobic surface to make the surface layer have excellent super-hydrophobic performance and obtain stronger super-hydrophobic performance, but also can improve the dielectric properties of titanium dioxide powder and enhance the wave absorption performance of the fluorocarbon super-hydrophobic surface layer, in combination with the strong hydrophobicity and corrosion resistance of fluorocarbon resin, the super-hydrophobicity and corrosion resistance of the coating are further improved, (3) the mixture of micro-sized titanium dioxide powder and nano-sized titanium dioxide powder can obtain a better rough structure to enhance the super-hydrophobicity and wear resistance of the coating. Therefore, the present application can obtain excellent super-hydrophobicity, the water contact angle of the coating can reach 167°, and the rolling angle can reach 2°, the excellent super-hydrophobicity makes the wave absorption coating have excellent corrosion resistance and self-cleaning performance, the salt spray test time can reach more than 4000 hours, and the water contact angle of the coating can be maintained at 159°, the rolling angle can be maintained at 9°, still having good super-hydrophobicity and self-cleaning performance, which can meet the application requirements of equipment in marine and other high corrosion resistance required occasions.

[0022] 2、The present application adopts titanium dioxide coated magnetic wave absorber, and then hydrogenation treatment is carried out to produce a disorder layer on the surface of titanium dioxide, forming a composite wave absorber with multi-level core-shell structure, which can not only improve the corrosion resistance of magnetic absorber, but also greatly enhance the interface polarization loss and dielectric loss of titanium dioxide, and improve its wave absorption performance. The composite wave absorber with core-shell structure can further improve the corrosion resistance of the wave absorber after super-hydrophobic modification, therefore, the composite wave absorber with multi-level core-shell structure is combined with epoxy resin, the environmental stability and strong adhesion of epoxy resin are utilized, and the mixture forms an epoxy wave absorption bottom layer, which can enhance the corrosion resistance and bonding strength of the coating.

[0023] 3、The wave-absorbing coating of the present application adopts a double-layer structure design of an epoxy wave-absorbing bottom layer and a fluorocarbon super-hydrophobic surface layer, the epoxy wave-absorbing bottom layer can improve the binding force of the fluorocarbon super-hydrophobic surface layer while playing excellent wave-absorbing performance through the multi-stage core-shell structure wave-absorbing agent; the fluorocarbon super-hydrophobic surface layer plays a protective role through the super-hydrophobic characteristics to improve the corrosion resistance and self-cleaning performance of the wave-absorbing coating, and on the other hand, the dielectric properties of titanium dioxide can be adjusted through hydrogenation treatment time, which can play the effect of an impedance matching layer to improve the overall wave-absorbing effect of the coating. The corrosion-resistant wave-absorbing coating provided by the present application can reach a maximum loss intensity of -69.8 dB at 2-18 GHz, and the effective wave-absorbing bandwidth can reach 11.3 GHz, and the excellent wave-absorbing performance is combined with excellent corrosion resistance.

[0024] 4、The present application has a wide range of applications, and the base materials used include aluminum alloy, magnesium alloy, titanium alloy or stainless steel, etc., and is suitable for equipping various ships, etc. in a marine environment with strong corrosion. DETAILED DESCRIPTION

[0025] The technical solutions provided by the present application are further described in detail below in combination with specific embodiments, and the examples are only used to explain the present application and not to limit the scope of the present application.

[0026] The magnetic wave-absorbing particles described in the present application are commercially available products such as carbonyl iron powder, ferrite powder and magnetic alloy powder.

[0027] Embodiment 1: A preparation method of a corrosion-resistant super-hydrophobic wave-absorbing coating, comprising the following steps:

[0028] (1) Preparation of a core-shell structure corrosion-resistant wave-absorbing agent:

[0029] First, 20g of carbonyl iron powder with a particle size of 1um is added to 150g of titanium dioxide sol, stirred at 900rpm for 2 hours at 60℃, and then collected by centrifugation, washed with anhydrous ethanol and dried at 60℃, to obtain a core-shell structure powder of titanium dioxide coated carbonyl iron powder;

[0030] Then, the core-shell structure powder is heat-treated at 550℃ for 6 hours in a hydrogen atmosphere of 0.5MPa to obtain a composite wave-absorbing agent powder;

[0031] Finally, the composite wave-absorbing agent powder is uniformly dispersed in a mixed solution of 800g of anhydrous ethanol / water (volume ratio 11:1), 2.5g of butyl titanate, 1.2g of ammonia water and 7.5g of perfluorodecyltrimethoxysilane are added in sequence, stirred for 2 hours, collected by centrifugation and dried at 60℃ for 48 hours to obtain a core-shell structure wave-absorbing agent powder with super-hydrophobic properties.

[0032] The preparation process of the titanium dioxide sol is as follows: 10 mL of butyl titanate is added dropwise into 50 mL of anhydrous ethanol and stirred to mix uniformly, then 10 mL of deionized water is slowly added, and the pH value of the solution is adjusted to 3 with glacial acetic acid, and the stirring is continued for 0.5 hours to obtain a transparent titanium dioxide sol.

[0033] (2) Preparation of the epoxy wave-absorbing bottom layer: 60 g of epoxy resin is diluted with 10 g of diluent, then 168 g of the above-mentioned core-shell structure wave-absorbing agent powder is added and stirred with a high-speed mixer for 2 hours to mix uniformly, then 8 g of an epoxy curing agent is added and stirred for 15 minutes, and then the mixture is sprayed on an aluminum alloy substrate and cured at 60°C for 5 hours to obtain an epoxy wave-absorbing bottom layer, and the thickness of the bottom layer coating is 2.4 mm.

[0034] (3) Preparation of fluorosilane-modified micro-nano hierarchical titanium dioxide powder:

[0035] First, 5 g of anatase titanium dioxide with a particle size of 1 um and 12 g of anatase titanium dioxide powder with a particle size of 15 nm are uniformly mixed;

[0036] Then, the mixture is heat-treated at 425°C for 3 hours in a hydrogen atmosphere at 0.5 MPa to obtain hydrogen-treated micro-nano hierarchical titanium dioxide powder;

[0037] Finally, 10 g of the hydrogen-treated micro-nano hierarchical titanium dioxide powder is uniformly dispersed in a mixed solution of 500 g of anhydrous ethanol / water (volume ratio 10:1), 0.8 g of tetraethyl orthosilicate, 3 g of an organic silicon hydrophobic agent, and 5 g of perfluorodecyltrimethoxysilane are sequentially added, stirred for 2 hours, collected by centrifugation, and dried at 60°C for 48 hours to obtain fluorosilane-modified micro-nano hierarchical titanium dioxide powder.

[0038] (4) Preparation of a fluorocarbon super-hydrophobic surface layer:

[0039] First, 10 g of a diluent is added to 50 g of fluorocarbon resin, then 20 g of fluorosilane-modified micro-nano hierarchical titanium dioxide powder is added, and the mixture is stirred with a high-speed mixer for 2 hours to mix uniformly, then 8 g of a fluorocarbon curing agent is added and stirred for 15 minutes, and then the mixture is sprayed on the epoxy wave-absorbing bottom layer, dried at room temperature for 24 hours, and the fluorocarbon super-hydrophobic surface layer is cured, and the thickness of the surface layer is controlled to be 0.4 mm to obtain a corrosion-resistant super-hydrophobic wave-absorbing coating.

[0040] It is detected that the water contact angle of the corrosion-resistant super-hydrophobic wave-absorbing coating obtained in the embodiment is 167°, the rolling angle is 2°, the coating has excellent super-hydrophobic performance and self-cleaning performance; the maximum loss intensity of the coating in the frequency range of 2-18 GHz is -69.8 dB, the effective wave-absorbing bandwidth is 11.3 GHz, and the coating has excellent wave-absorbing performance; after 4000 hours of salt spray test, the water contact angle of the coating is maintained at 159°, the rolling angle is maintained at 9°, and the wave-absorbing performance is basically unchanged, so the coating has good corrosion resistance and wave-absorbing performance.

[0041] Example 2, a method for preparing a corrosion-resistant super-hydrophobic wave-absorbing coating, comprising the following steps:

[0042] (1) Preparation of a core-shell structure corrosion-resistant wave-absorbing agent:

[0043] First, 20 g of ferrite powder with a particle size of 2 um is added to 100 g of titanium dioxide sol, stirred at 1000 revolutions per minute for 2 hours at 60°C, then collected by centrifugation, washed with anhydrous ethanol, and dried at 60°C to obtain a core-shell structure powder of titanium dioxide coated ferrite powder;

[0044] Then, the core-shell structure powder is heat treated at 500°C for 6 hours in a hydrogen atmosphere of 0.5 MPa to obtain a composite wave-absorbing agent powder;

[0045] Finally, the composite wave-absorbing agent powder is uniformly dispersed in a mixed solution of 750 g of anhydrous ethanol / water (volume ratio 11:1), 2 g of butyl titanate, 2 g of ammonia water, and 10 g of perfluorodecyl triethoxysilane are added in turn, stirred for 2 hours, collected by centrifugation, and dried at 60°C for 48 hours to obtain a core-shell structure wave-absorbing agent powder with super-hydrophobic properties.

[0046] The preparation process of the titanium dioxide sol is as follows: first, 10 mL of butyl titanate is added dropwise to 50 mL of anhydrous ethanol and stirred to mix uniformly, then 10 mL of deionized water is slowly added, and the pH value of the solution is adjusted to 3 with glacial acetic acid, and stirring is continued for 0.5 hours to obtain a transparent titanium dioxide sol.

[0047] (2) Preparation of an epoxy wave-absorbing bottom layer: 60 g of epoxy resin is diluted with 10 g of diluent, then 130 g of the above-mentioned core-shell structure wave-absorbing agent powder is added, and a high-speed mixer is used to stir for 2 hours to make the mixture uniform, then 9 g of an epoxy curing agent is added and stirred for 15 minutes, then it is sprayed on an aluminum alloy substrate and cured at 60°C for 5 hours to obtain an epoxy wave-absorbing bottom layer, with a bottom layer coating thickness of 2 mm.

[0048] (3) Preparation of fluorosilane-modified micro-nano hierarchical titanium dioxide powder:

[0049] First, 4 g of anatase phase titanium dioxide with a particle size of 2 um and 10 g of anatase phase titanium dioxide powder with a particle size of 20 nm are uniformly mixed;

[0050] Then, the micro-nano hierarchical titanium dioxide powder is heat treated at 425°C for 2 hours in a hydrogen atmosphere of 0.5 MPa to obtain a hydrogenated micro-nano hierarchical titanium dioxide powder;

[0051] Finally, 11 g of the hydrogen-treated micro-nano hierarchical titanium dioxide powder was uniformly dispersed in a mixed solution of 500 g of anhydrous ethanol / water (volume ratio 10:1), 1 g of tetraethyl orthosilicate, 3.3 g of an organic silicon hydrophobic agent, and 5 g of perfluorodecyltrimethoxysilane were added in sequence, stirred for 2 hours, collected by centrifugation, and dried at 60°C for 48 hours to obtain fluorosilane-modified micro-nano hierarchical titanium dioxide powder.

[0052] (4) Preparation of a fluorocarbon super-hydrophobic surface layer: 10 g of a diluent was added to 50 g of a fluorocarbon resin, then 15 g of the fluorosilane-modified micro-nano hierarchical titanium dioxide powder was added, and a high-speed blender was used for stirring for 2 hours to make the mixture uniform, 9 g of a fluorocarbon curing agent was then added, and stirring was continued for 15 minutes, after which the fluorocarbon super-hydrophobic surface layer was sprayed on the epoxy wave-absorbing bottom layer, dried at room temperature for 24 hours, and the fluorocarbon super-hydrophobic surface layer was cured, with the surface layer thickness controlled at 0.2 mm, to obtain a corrosion-resistant super-hydrophobic wave-absorbing coating.

[0053] It was detected that the corrosion-resistant super-hydrophobic wave-absorbing coating obtained in this embodiment had a water contact angle of 162° and a rolling angle of 4°, had good super-hydrophobic performance and self-cleaning performance, had a maximum loss intensity of -55.2 dB at 2-18 GHz and an effective wave-absorbing bandwidth of 7.9 GHz, and had excellent wave-absorbing performance; after a 3800-hour salt spray test, the water contact angle remained at 159°, the rolling angle remained at 9°, and the wave-absorbing performance remained basically unchanged, so the coating had good corrosion resistance and wave-absorbing performance.

[0054] Example 3, a method for preparing a corrosion-resistant super-hydrophobic wave-absorbing coating, comprising the following steps:

[0055] (1) Preparation of a core-shell structure corrosion-resistant wave-absorbing agent:

[0056] First, 18 g of Co3Fe7 magnetic alloy powder with a particle size of 1 um was added to 140 g of titanium dioxide sol, and stirring was performed at 1000 rpm at 60°C for 2.5 hours, after which the core-shell structure powder of titanium dioxide-coated Co3Fe7 powder was collected by centrifugation, washed with anhydrous ethanol, and dried at 60°C;

[0057] Then, the core-shell structure powder was heat-treated at 550°C for 5 hours in a hydrogen atmosphere at 0.5 MPa to obtain a composite wave-absorbing agent powder.

[0058] Finally, the composite wave-absorbing agent powder was uniformly dispersed in a mixed solution of 650 g of anhydrous ethanol / water (volume ratio 11:1), 1.6 g of butyl titanate, 1.4 g of ammonia water, and 8 g of perfluorodecyltrichlorosilane were added in sequence, stirred for 2 hours, collected by centrifugation, and dried at 60°C for 48 hours to obtain a core-shell structure wave-absorbing agent powder with super-hydrophobic properties.

[0059] The preparation process of the titanium dioxide sol is as follows: 10 mL of butyl titanate is added dropwise into 50 mL of anhydrous ethanol and stirred to mix uniformly, then 10 mL of deionized water is slowly added, and the pH value of the solution is adjusted to 2.5 with glacial acetic acid, and the stirring is continued for 0.5 hours to obtain a transparent titanium dioxide sol.

[0060] (2) Preparation of the epoxy wave-absorbing bottom layer: 70 g of epoxy resin is diluted with 10 g of diluent, then 94 g of the above-mentioned core-shell structure wave-absorbing agent powder is added and stirred with a high-speed stirrer for 2 hours to mix uniformly, then 14 g of an epoxy curing agent is added and stirred for 15 minutes, and then the mixture is sprayed on an aluminum alloy substrate and cured at 60°C for 5 hours to obtain an epoxy wave-absorbing bottom layer, and the thickness of the bottom layer coating is 2.2 mm.

[0061] (3) Preparation of fluorosilane-modified micro-nano hierarchical titanium dioxide powder:

[0062] First, 6 g of rutile titanium dioxide with a particle size of 1 um and 11 g of rutile titanium dioxide powder with a particle size of 10 nm are uniformly mixed;

[0063] Then, the mixture is heat-treated at 425°C for 3 hours in a hydrogen atmosphere at 0.5 MPa to obtain hydrogen-treated micro-nano hierarchical titanium dioxide powder;

[0064] Finally, 8 g of the hydrogen-treated micro-nano hierarchical titanium dioxide powder is uniformly dispersed in a mixed solution of 350 g of anhydrous ethanol / water (volume ratio 10:1), 0.7 g of tetraethyl orthosilicate, 3 g of an organic silicon hydrophobic agent, and 4 g of perfluorodecyltrimethoxysilane are added in sequence, stirred for 2 hours, collected by centrifugation, and dried at 60°C for 48 hours to obtain fluorosilane-modified micro-nano hierarchical titanium dioxide powder.

[0065] (4) Preparation of a fluorocarbon super-hydrophobic surface layer: 10 g of a diluent is added to 50 g of a fluorocarbon resin, then 18 g of the fluorosilane-modified micro-nano hierarchical titanium dioxide powder is added and stirred with a high-speed stirrer for 2 hours to mix uniformly, then 8 g of a fluorocarbon curing agent is added and stirred for 15 minutes, and then the mixture is sprayed on the epoxy wave-absorbing bottom layer, dried at room temperature for 24 hours, and the fluorocarbon super-hydrophobic surface layer is cured, and the thickness of the surface layer is controlled to be 0.3 mm to obtain a corrosion-resistant super-hydrophobic wave-absorbing coating.

[0066] It is detected that the water contact angle of the corrosion-resistant super-hydrophobic wave-absorbing coating obtained in the embodiment is 165°, the rolling angle is 3°, the coating has good super-hydrophobic performance and self-cleaning performance, the maximum loss intensity of the coating in the frequency range of 2-18 GHz is -61.3 dB, the effective wave-absorbing bandwidth is 8.5 GHz, and the coating has excellent wave-absorbing performance; after 4000 hours of salt spray test, the water contact angle of the coating is maintained at 160°, the rolling angle is maintained at 7°, and the wave-absorbing performance is basically unchanged, so the coating has good corrosion resistance and wave-absorbing performance.

[0067] Example 4, a method for preparing a corrosion-resistant super-hydrophobic wave-absorbing coating, comprising the following steps:

[0068] (1) Preparation of a core-shell structure corrosion-resistant wave-absorbing agent:

[0069] First, 18 g of carbonyl iron powder with a particle size of 2 um is added to 200 g of titanium dioxide sol, stirred at 1000 revolutions per minute for 3 hours at 60°C, then collected by centrifugation, washed with anhydrous ethanol, and dried at 60°C to obtain a core-shell structure powder of titanium dioxide coated carbonyl iron powder;

[0070] Then, the core-shell structure powder is heat treated at 450°C for 6 hours in a hydrogen atmosphere of 0.5 MPa to obtain a composite wave-absorbing agent powder;

[0071] Finally, the composite wave-absorbing agent powder is uniformly dispersed in a mixed solution of 500 g of anhydrous ethanol / water (volume ratio 11:1), 1.2 g of butyl titanate, 1 g of ammonia water, and 7 g of perfluorooctyltrichlorosilane are added in turn, stirred for 2 hours, collected by centrifugation, and dried at 60°C for 48 hours to obtain a core-shell structure wave-absorbing agent powder with super-hydrophobic properties.

[0072] The preparation process of the titanium dioxide sol is as follows: first, 10 mL of butyl titanate is added dropwise to 50 mL of anhydrous ethanol and stirred to mix uniformly, then 10 mL of deionized water is slowly added, and the pH value of the solution is adjusted to 2.5 with glacial acetic acid, and stirring is continued for 0.5 hours to obtain a transparent titanium dioxide sol.

[0073] (2) Preparation of an epoxy wave-absorbing bottom layer: 80 g of epoxy resin is diluted with 10 g of diluent, then 100 g of the above-mentioned core-shell structure wave-absorbing agent powder is added, and a high-speed mixer is used to stir for 2 hours to make the mixture uniform, then 10 g of an epoxy curing agent is added, and stirring is continued for 15 minutes, then it is sprayed onto an aluminum alloy substrate, and cured at 60°C for 6 hours to obtain an epoxy wave-absorbing bottom layer, with a bottom layer coating thickness of 1.5 mm.

[0074] (3) Preparation of fluorosilane-modified micro-nano hierarchical titanium dioxide powder:

[0075] First, 5 g of rutile phase titanium dioxide powder with a particle size of 1 um and 15 g of anatase phase titanium dioxide powder with a particle size of 10 nm are uniformly mixed;

[0076] Then, the micro-nano hierarchical titanium dioxide powder is heat treated at 425°C for 4 hours in a hydrogen atmosphere of 0.5 MPa to obtain a hydrogenated micro-nano hierarchical titanium dioxide powder;

[0077] Finally, 5 g of the hydrogen-treated micro-nano hierarchical titanium dioxide powder was uniformly dispersed in 250 g of a mixed solution of anhydrous ethanol / water (volume ratio 10:1), 0.45 g of tetraethyl orthosilicate, 3 g of an organic silicon hydrophobic agent, and 2 g of perfluorodecyltrimethoxysilane were sequentially added, stirring was performed for 2 hours, centrifugal collection was performed, and then 60°C drying was performed for 48 hours to obtain fluorosilane-modified micro-nano hierarchical titanium dioxide powder.

[0078] (4) Fluorocarbon super-hydrophobic surface layer preparation: 10 g of a diluent was added to 45 g of fluorocarbon resin, then 25 g of fluorosilane-modified micro-nano hierarchical titanium dioxide powder was added, and a high-speed mixer was used for stirring for 2 hours to uniformly mix the same, 8 g of a fluorocarbon curing agent was then added, stirring was continued for 15 minutes, and then the fluorocarbon super-hydrophobic surface layer was sprayed on the epoxy wave-absorbing bottom layer, drying was performed at room temperature for 24 hours, the fluorocarbon super-hydrophobic surface layer was cured, the surface layer thickness was controlled to be 0.3 mm, and a corrosion-resistant super-hydrophobic wave-absorbing coating was obtained.

[0079] It was detected that the water contact angle of the corrosion-resistant super-hydrophobic wave-absorbing coating obtained in this embodiment was 167°, the rolling angle was 2°, the super-hydrophobic performance and the self-cleaning performance were good, the maximum loss intensity of the coating was -60.5 dB at 2-18 GHz, the effective wave-absorbing bandwidth was 7.6 GHz, the wave-absorbing performance was excellent, the water contact angle remained at 161° after 4100 hours of salt spray testing, the rolling angle remained at 7°, and the wave-absorbing performance remained basically unchanged, so that the corrosion resistance and the wave-absorbing performance were both good.

[0080] Embodiment 5, a preparation method of a corrosion-resistant super-hydrophobic wave-absorbing coating, comprising the following steps:

[0081] (1) Preparation of a core-shell structure corrosion-resistant wave-absorbing agent:

[0082] First, 10 g of ferrite powder with a particle size of 1 um was added to 60 g of titanium dioxide sol, stirring was performed at 1000 revolutions / minute at 60°C for 3 hours, and then centrifugal collection, anhydrous ethanol cleaning, and 60°C drying treatment were performed to obtain a core-shell structure powder of titanium dioxide-coated ferrite powder;

[0083] Then, the core-shell structure powder was heat-treated at 550°C for 6 hours in a hydrogen atmosphere at 0.5 MPa to obtain a composite wave-absorbing agent powder;

[0084] Finally, the composite wave-absorbing agent powder was uniformly dispersed in 500 g of a mixed solution of anhydrous ethanol / water (volume ratio 11:1), 1.5 g of butyl titanate, 1 g of ammonia water, and 8 g of perfluorodecyltrimethoxysilane were sequentially added, stirring was performed for 2 hours, centrifugal collection was performed, and then 60°C drying was performed for 48 hours to obtain a core-shell structure wave-absorbing agent powder with super-hydrophobic properties.

[0085] The preparation process of the titanium dioxide sol is as follows: 10 mL of butyl titanate is added dropwise into 50 mL of anhydrous ethanol, stirred and mixed uniformly, then 10 mL of deionized water is slowly added, the pH value of the solution is adjusted to 4 with glacial acetic acid, and continuous stirring is performed for 0.5 hours to obtain a transparent titanium dioxide sol.

[0086] (2) Preparation of the epoxy wave-absorbing bottom layer: 100 g of epoxy resin is diluted after 15 g of diluent is added, then 310 g of the above-mentioned core-shell structure wave-absorbing agent powder is added, and a high-speed stirrer is used for stirring for 2 hours, so that the mixture is uniformly mixed, then 15 g of an epoxy curing agent is added, and stirring is continuously performed for 15 minutes, then the mixture is sprayed on an aluminum alloy substrate, and curing is performed at 60℃ for 6 hours to obtain an epoxy wave-absorbing bottom layer, and the thickness of the bottom layer coating is 2.5 mm.

[0087] (3) Preparation of fluorosilane-modified micro-nano hierarchical titanium dioxide powder: 10 g of anatase phase titanium dioxide with a particle size of 1 um and 25 g of anatase phase titanium dioxide powder with a particle size of 10 nm are uniformly mixed, then hydrogenation treatment of the micro-nano hierarchical titanium dioxide powder is performed at 425℃ for 4 hours in a hydrogen atmosphere at a pressure of 0.5 MPa, 6 g of the hydrogenation-treated micro-nano hierarchical titanium dioxide powder is uniformly dispersed in a mixed solution of 300 g of anhydrous ethanol / water (a volume ratio of 10:1), 0.57 g of tetraethyl orthosilicate, 6 g of an organic silicon hydrophobic agent and 10 g of perfluorodecyltrimethoxysilane are sequentially added, stirring is performed for 2 hours, centrifugal collection is performed, and 60℃ drying is performed for 48 hours to obtain fluorosilane-modified micro-nano hierarchical titanium dioxide powder.

[0088] (4) Preparation of a fluorocarbon super-hydrophobic surface layer: 10 g of a diluent is added to 40 g of fluorocarbon resin, then 20 g of fluorosilane-modified micro-nano hierarchical titanium dioxide powder is added, a high-speed stirrer is used for stirring for 2 hours, so that the mixture is uniformly mixed, then 8 g of a fluorocarbon curing agent is added, and stirring is continuously performed for 15 minutes, then the mixture is sprayed on the epoxy wave-absorbing bottom layer, drying is performed at room temperature for 24 hours, and the fluorocarbon super-hydrophobic surface layer is cured, the thickness of the surface layer is controlled to be 0.5 mm, and an anti-corrosion super-hydrophobic wave-absorbing coating is obtained.

[0089] It is detected that the water contact angle of the anti-corrosion super-hydrophobic wave-absorbing coating obtained in the embodiment is 166°, the rolling angle is 2°, the coating has excellent super-hydrophobic performance and self-cleaning performance, the maximum loss intensity of the coating in a frequency range of 2-18 GHz is-66.2 dB, the effective wave-absorbing bandwidth is 10.5 GHz, the coating has excellent wave-absorbing performance, the water contact angle of the coating remains at 158° after a 4000-hour salt spray test, the rolling angle remains at 8°, and the wave-absorbing performance remains basically unchanged, so that the coating has good anti-corrosion and wave-absorbing performance.

[0090] In the above-mentioned embodiments, the embodiment 1 is the best embodiment.

[0091] The above merely illustrates some embodiments of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a corrosion-resistant superhydrophobic microwave absorbing coating, characterized in that: Includes the following steps: (1) Preparation of core-shell structure corrosion-resistant microwave absorbing agent powder: First, magnetic microwave absorbing particles are added to titanium dioxide sol and stirred, collected, washed and dried to obtain core-shell structure powder of titanium dioxide coated magnetic microwave absorbing particles; then, the core-shell structure powder is heat-treated at 400~550℃ for 2~6 hours in a hydrogen atmosphere to obtain composite microwave absorbing agent powder; finally, the composite microwave absorbing agent is uniformly dispersed in anhydrous ethanol / water mixed solution, and tetrabutyl titanate, ammonia and fluorosilane are added in sequence, stirred and collected and dried to obtain core-shell structure corrosion-resistant microwave absorbing agent powder with superhydrophobic properties; (2) Preparation of epoxy microwave absorbing substrate: After diluting the epoxy resin with a diluent, add the core-shell structure corrosion-resistant microwave absorbing agent powder, stir at high speed to make it evenly mixed, add the epoxy curing agent, continue stirring, and then spray it on the substrate and cure to obtain the epoxy microwave absorbing substrate. (3) Preparation of fluorosilane-modified micro-nano hierarchical titanium dioxide powder: First, micron-sized and nano-sized titanium dioxide powders are uniformly mixed, and then heat-treated at 400-450℃ for 2-4 hours in a protective hydrogen atmosphere to obtain hydrogenated micro-nano hierarchical titanium dioxide powder; finally, the hydrogenated micro-nano hierarchical titanium dioxide powder is uniformly dispersed in anhydrous ethanol / water mixed solution, and tetraethyl orthosilicate, organosilicon hydrophobic agent and fluorosilane are added in sequence, stirred for 1-3 hours, collected by centrifugation, and dried at 60℃ for 48 hours to obtain fluorosilane-modified micro-nano hierarchical titanium dioxide powder; (4) Preparation of fluorocarbon superhydrophobic surface layer: First, dilute the fluorocarbon resin with a diluent, then add fluorosilane-modified micro-nano graded titanium dioxide powder, stir with a high-speed mixer to make it evenly mixed, then add fluorocarbon curing agent, continue stirring, then spray it on the epoxy microwave absorbing substrate, dry at room temperature, the fluorocarbon superhydrophobic surface layer is cured, and a corrosion-resistant superhydrophobic microwave absorbing coating is obtained.

2. The method for preparing a corrosion-resistant superhydrophobic absorbing coating according to claim 1, characterized in that: The thickness of the fluorocarbon superhydrophobic surface layer is 0.1~1mm; the thickness of the epoxy microwave absorbing bottom layer is 0.8~3mm.

3. The method for preparing a corrosion-resistant superhydrophobic absorbing coating according to claim 2, characterized in that: In step (1) of the preparation of the core-shell structure powder, the mass ratio of magnetic absorbing particles to titanium dioxide sol is 1:4~1:10; in the preparation of the core-shell structure corrosion-resistant absorbing agent powder, the mass ratio of anhydrous ethanol / water mixed solution, composite absorbing agent, tetrabutyl titanate, ammonia and fluorosilane is 500:10~20:1~1.5:0.3~2:5~8.

4. The method for preparing a corrosion-resistant superhydrophobic absorbing coating according to claim 2, characterized in that: The preparation process of titanium dioxide sol in step (1) is as follows: first, tetrabutyl titanate is added dropwise to anhydrous ethanol and stirred until evenly mixed. Then, deionized water is slowly added and the pH value of the solution is adjusted to 2~4 with glacial acetic acid. The solution is stirred continuously to obtain transparent titanium dioxide sol. The volume ratio of anhydrous ethanol, tetrabutyl titanate and deionized water is 5:1:

1.

5. A method for preparing a corrosion-resistant superhydrophobic absorbing coating according to claim 3 or 4, characterized in that: In step (2), the mass ratio of epoxy resin to epoxy curing agent is controlled at 10:1 to 10:3, the mass ratio of epoxy resin to diluent is controlled at 11:1 to 5:1, and the mass ratio of epoxy resin to core-shell structure corrosion-resistant microwave absorbing agent powder is controlled at 1:3 to 2:

1.

6. The method for preparing a corrosion-resistant superhydrophobic absorbing coating according to claim 5, characterized in that: In step (3), the crystal phase structure of the titanium dioxide powder is one of anatase phase, rutile phase or a mixture of the two. The particle size of the micron-sized titanium dioxide powder is 1~3um, the particle size of the nano-sized titanium dioxide powder is 5~30nm, and the mass ratio of the micron-sized titanium dioxide powder to the nano-sized titanium dioxide powder is 1:1~1:

4.

7. The method for preparing a corrosion-resistant superhydrophobic absorbing coating according to claim 6, characterized in that: In step (3), the mass ratio of anhydrous ethanol / water to micro / nano graded titanium dioxide powder is controlled at 50:1 to 50:3, the mass ratio of micro / nano graded titanium dioxide powder to tetraethyl orthosilicate is 12:1 to 10:1, the mass ratio of organosilicon hydrophobic agent to fluorosilane is 3:4 to 3:5, and the mass ratio of micro / nano graded titanium dioxide powder to fluorosilane is 3:1 to 2:

1.

8. The method for preparing a corrosion-resistant superhydrophobic absorbing coating according to claim 7, characterized in that: In step (4), the mass ratio of fluorocarbon resin to fluorocarbon curing agent is controlled at 5:1 to 7:1, the mass ratio of fluorocarbon resin to diluent is 5:1 to 4:1, and the mass ratio of fluorocarbon resin to fluorosilane-modified micro-nano graded titanium dioxide powder is controlled at 5:1 to 1:

1.

9. The method for preparing a corrosion-resistant superhydrophobic absorbing coating according to claim 8, characterized in that: In step (1), the fluorosilane is perfluorodecyltrimethoxysilane, perfluorodecyltriethoxysilane, perfluorodecyltrichlorosilane or perfluorooctyltrichlorosilane.

10. A corrosion-resistant superhydrophobic microwave absorbing coating prepared by the method according to claim 1.