A wave-absorbing and heat-conducting super-hydrophobic anti-corrosion coating and its preparation method

Abstract

The invention discloses wave-absorbing heat-conducting super-hydrophobic anti-corrosion coating and preparation method thereof, preparation method specifically comprises the following steps: first at BNNS surface load carbon nanoparticles and SiO2Nanoparticles obtain 1 BNNS / C / SiO2, subsequently prepare porous hollow SiO2Coating BNNS / C composite material (2 BNNS / C / SiO2), mix double structure BNNS / C / SiO2As polyurethane filler, obtain wave-absorbing heat-conducting super-hydrophobic anti-corrosion coating.Coating of the present invention is by polyurethane matrix and two kinds of BNNS / C / SiO2 of different structuresComposite material is composed, wherein 1 BNNS / C / SiO2The structure of composite material is: BNNS surface uniformly loads carbon nanoparticles, and then uniformly grows SiO2microspheres on its surface;2 BNNS / C / SiO2The structure of composite material is: porous mesoporous SiO2The BNNS of uniformly loaded carbon nanoparticles is wrapped therein by microspheres. The wave-absorbing, heat-conducting, super-hydrophobic anti-corrosion coating prepared by this invention leverages the close adhesion of carbon nanoparticles and SiO2 nanoparticles on the BNNS surface to create a highly efficient conductive network and heat conduction path. Furthermore, the BNNS and porous SiO2 microspheres optimize impedance and enhance wave absorption.

Description

Technical Field

[0001] The invention belongs to the field of metal surface coating protection and relates to a method for preparing a wave-absorbing and heat-conducting super-hydrophobic anti-corrosion coating. Background Art

[0002] In the field of metal surface coating protection, the rapid advancement of science and technology and the continuous expansion of industrial applications have led to increasingly stringent requirements for the functionality and performance of coating materials. These materials not only need to resist environmental erosion, but also must achieve efficient thermal management, electromagnetic shielding, and excellent waterproof and anti-fouling functions under extreme conditions. For example, in the aerospace field, the extreme conditions such as high temperature, high-speed friction, and strong electromagnetic radiation brought about by high-speed flight require coating materials to have excellent thermal conductivity to quickly dissipate heat, efficient wave absorption to reduce radar reflection cross section, and super hydrophobicity to prevent the accumulation of water droplets in high-altitude environments, thereby ensuring the safety and stability of aircraft. In the field of electronic communications, as electronic equipment develops towards higher integration, electromagnetic interference and thermal management have become key factors restricting their performance.

[0003] Although traditional coating fillers can protect the metal substrate from environmental factors such as corrosion and wear to a certain extent, their limitations are gradually becoming apparent in the face of increasingly complex and diversified demands in modern industry. For example, thermal conductive materials such as graphene and carbon nanotubes are widely used in coating fillers due to their excellent thermal conductivity, which greatly improves the thermal management efficiency of the coating. However, when these materials are used alone, their wave absorption performance is difficult to meet high performance requirements, limiting their application in key areas such as electromagnetic shielding. At the same time, superhydrophobic materials such as fluorinated polymers and nanostructured surfaces effectively reduce the adhesion of moisture and pollutants through their unique surface properties, but often sacrifice other key properties. Therefore, the development of a multifunctional coating that can simultaneously take into account thermal conductivity, wave absorption and superhydrophobic properties has become a hot topic of current research.

[0004] The Chinese patent "A high-temperature resistant absorbing coating with a low thermal expansion coefficient and its preparation method" (application number: CN202311453978.9, publication number: CN117363068A, announcement date: 2024.01.09) provides a high-temperature resistant absorbing coating with a low thermal expansion coefficient and its preparation method. The high-temperature absorbing coating in this application has a low thermal expansion coefficient and can achieve good thermal matching with a substrate formed of a low expansion coefficient material. After annealing in a high-temperature environment, it can still effectively absorb electromagnetic waves, thereby improving the target's absorbing performance and service life in a high-temperature environment. However, its functionality or adaptability is relatively single, and it is difficult to fully cope with complex and changing environmental conditions.

[0005] The Chinese patent "A self-cleaning, waterproof and anti-corrosion powder coating and its preparation method" (application number: CN202410853650.4, publication number: CN118440569A, announcement date: 2024.08.06) provides a self-cleaning, waterproof and anti-corrosion powder coating and its preparation method. The coating is composed of modified polyester-epoxy powder coating, nano-active powder and dispersant. Although it has excellent corrosion resistance, high hardness, wear resistance, waterproof and self-cleaning properties, its performance coverage is not comprehensive, which limits its application in a wider range of fields.

[0006] The Chinese patent "A homogeneous flexible super-hydrophobic absorbing coating and its preparation method and application" (application number: CN202310835078.4, publication number: CN116855120A, announcement date: 2023.10.10) discloses a homogeneous flexible super-hydrophobic absorbing coating and its preparation method and application. By modifying the absorbing material through organic-inorganic hybridization, sulfur radicals are grafted to the surface of the absorber by reverse vulcanization reaction. At the same time, the monomer wraps it, which can reduce the dielectric property of the material and improve the impedance mismatch. A coating with certain super-hydrophobicity and good absorbing performance is obtained. However, materials with high electromagnetic loss are often accompanied by higher thermal conductivity. Excessive thermal conductivity may be detrimental to the local accumulation and control of heat, limiting its application field.

[0007] The Chinese patent "A High Thermal Conductivity Coated Aluminum Foil and Its Preparation Process" (Application Number: CN202410794297.7, Publication Number: CN118359981A, Announcement Date: November 18, 2015) discloses a high thermal conductivity coated aluminum foil and its preparation process. The invention uses polyethylene glycol as a core material, adds benzotriazole as an anticorrosive agent, and then uses lead tungstate (a thermally conductive material) as a shell to create a thermally conductive and corrosion-resistant microcapsule. The surface of the microcapsule is then coated with a layer of silicon dioxide to further enhance its corrosion resistance. However, the invention also suffers from incomplete performance and limited application areas. Summary of the Invention

[0008] The present invention has two objectives. The first objective is to provide a method for preparing a wave-absorbing and heat-conducting super-hydrophobic anti-corrosion coating, which solves the problem that existing coatings are difficult to meet the diversified and high-performance requirements of high-efficiency wave absorption, excellent thermal conductivity, and super-hydrophobic surface properties. The second objective of the present invention is to provide a wave-absorbing and heat-conducting super-hydrophobic anti-corrosion coating, which solves the problem that existing coatings have poor electromagnetic shielding effect and weak thermal conductivity.

[0009] The present invention provides a method for preparing a wave-absorbing and heat-conducting super-hydrophobic anti-corrosion coating, which is specifically implemented according to the following steps:

[0010] Step 1: Preparation of Boron Nitride Nanosheets (BNNS)

[0011] Boron nitride particles were mixed with isopropanol and ball-milled, then ultrasonicated for 30 min using an ultrasonic cell crusher, centrifuged and filtered, washed three times with deionized water and ethanol respectively, and freeze-dried for 6 h to obtain boron nitride nanosheets (BNNS).

[0012] Step 2: Loading carbon nanoparticles

[0013] The BNNS obtained in step 1 and the water-soluble polymer are added to deionized water, heated in a water bath with stirring, dried, and calcined under a nitrogen atmosphere to obtain a BNNS / C composite material.

[0014] Step 3: Constructing a sandwich structure BNNS / C / SiO2 composite material

[0015] The BNNS / C composite material obtained in step 2 was ultrasonically dispersed in a mixed solution of anhydrous ethanol and deionized water, and then N,N,N',N'-tetramethyl-1,4-butanediamine (TMBDM), tetraethyl orthosilicate (TEOS), and hexamethyldisilazane (HMDS) were added in sequence. The mixture was stirred at room temperature for reaction. After centrifugation, it was washed three times with ethanol and deionized water, and finally dried to obtain a sandwich structure 1-BNNS / C / SiO2 composite material.

[0016] Step 4: Preparation of porous hollow SiO2-coated BNNS / C composite materials

[0017] The BNNS / C obtained in step 2 was ultrasonically dispersed in a mixed solution of anhydrous ethanol and deionized water, and then cetyltrimethylammonium bromide (CTAB) and ammonia water were added and stirred evenly; resorcinol was added under continuous stirring and reacted for 30 minutes, after which TEOS and formaldehyde were added dropwise and stirred at room temperature for reaction; the reaction product was centrifuged, washed with anhydrous ethanol and deionized water, dried, and calcined in a muffle furnace to obtain a porous hollow SiO2-coated BNNS / C composite material (2-BNNS / C / SiO2).

[0018] Step 5: Preparation of a wave-absorbing and heat-conducting super-hydrophobic anti-corrosion coating

[0019] The 1-BNNS / C / SiO2 composite material obtained in step 3 and the 2-BNNS / C / SiO2 composite material obtained in step 4 are mixed with polyurethane in a certain mass ratio, mixed evenly by a blender, and then ultrasonically dispersed, and the above stirring and ultrasonic dispersion are repeated multiple times; a curing agent is added, stirred evenly, and then applied to an aluminum plate, and after complete curing, a wave-absorbing and heat-conductive super-hydrophobic anti-corrosion coating is obtained.

[0020] The present invention discloses a wave-absorbing and heat-conducting super-hydrophobic anti-corrosion coating, which is composed of a polyurethane matrix and two BNNS / C / SiO2 composite materials with different structures. The structure of the 1-BNNS / C / SiO2 composite material is as follows: carbon nanoparticles are uniformly loaded on the surface of BNNS, and SiO2 microspheres are then uniformly grown on the surface; the structure of the 2-BNNS / C / SiO2 composite material is as follows: BNNS uniformly loaded with carbon nanoparticles are encapsulated in porous mesoporous SiO2 microspheres.

[0021] The present invention is also characterized in that:

[0022] In step 1, the ball-to-material ratio is 80:1-100:1, the agent-to-material ratio is 50:1-60:1, the rotation speed is 400r / min-500r / min, the ball milling time is 8h-12h; the centrifugal speed is 2000rpm-3000rpm, and the time is 15min-30min.

[0023] The mass ratio of BNNS to water-soluble polymer in step 2 is 1:5 to 1:10, the mass ratio of water-soluble polymer to deionized water is 1:30 to 1:50, the water-soluble polymer is any one of polyvinyl alcohol, sucrose, glucose, chitosan, etc., the stirring temperature is 80°C to 90°C, the stirring time is 1h to 2h, the drying temperature is 80°C, the drying time is 8h to 12h, and the calcination parameters are: heating rate of 3°C / min, calcination temperature of 800°C to 1000°C, and insulation time of 2h to 4h.

[0024] The concentration of BNNS / C in the mixed solution of anhydrous ethanol and deionized water in step 3 is 0.01 g / mL to 0.02 g / mL, the volume ratio of anhydrous ethanol to deionized water is 3:1 to 6:1, the volume ratios of TMBDM, HMDS, and TEOS to deionized water are 1:80 to 1:20, 1:10 to 1:30, and 1:1 to 1:3, respectively, the reaction time is 4 h to 8 h, the centrifugal speed is 2000 rpm to 3000 rpm, the centrifugal time is 15 min to 30 min, the drying temperature is 60 ° C to 80 ° C, and the drying time is 6 h to 12 h.

[0025] The concentration of BNNS / C in the mixed solution of anhydrous ethanol and deionized water in step 4 is 0.01 g / mL to 0.02 g / mL, the volume ratio of anhydrous ethanol to deionized water is 1:2 to 1:4, the mass ratio of BNNS / C to CTAB is 1:3 to 1:5, the volume ratio of ammonia water to anhydrous ethanol is 1:60 to 1:80, the mass ratio of resorcinol to CTAB is 1:2 to 2:1, the volume ratio of TEOS to anhydrous ethanol is 1:5 to 1:10, the volume ratio of formaldehyde to anhydrous ethanol is 1:10 to 1:20, the reaction time is 4 to 6 hours, the centrifugal speed is 2000 to 3000 rpm, the time is 15 to 30 minutes, the drying temperature is 60 to 80 degrees Celsius, the drying time is 6 to 12 hours, and the calcination parameters in the muffle furnace are: heating rate of 5 degrees Celsius / min, temperature of 550 degrees Celsius, and holding time of 4 to 6 hours.

[0026] In step 5, the mass ratio of the 1-BNNS / C / SiO2 composite material and the 2-BNNS / C / SiO2 composite material is 1:5 to 1:1, the filling rate of the total mass of the two composite materials in the polyurethane is 10% to 60%, the stirrer speed is 500 rpm to 800 rpm, the stirring time is 20 min to 60 min, the ultrasonic time is 15 min to 30 min, and the number of repetitions is 2 to 4 times. The curing agent is one of the trimers of toluene diisocyanate (TDI), 1,6-hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI), the mass ratio of the curing agent to the total mass of the 1-BNNS / C / SiO2 composite material and the 2-BNNS / C / SiO2 composite material is 1:500 to 1:1000, and the stirring time is 1 min to 3 min.

[0027] The beneficial effects of the present invention are: a method for preparing a wave-absorbing and heat-conducting super-hydrophobic anti-corrosion coating, which can obtain a multifunctional composite coating that integrates efficient wave absorption, excellent thermal conductivity and super-hydrophobic properties. Carbon nanoparticles are tightly attached to the BNNS surface, constructing an efficient conductive network, accelerating electron migration and polarization, and BNNS acts as an impedance matching layer to optimize electromagnetic absorption. By introducing porous SiO2 microspheres, not only the specific surface area is increased, but also its unique pores are used to achieve effective scattering and absorption of electromagnetic waves. Furthermore, BNNS with excellent thermal conductivity is combined with carbon nanoparticles and SiO2 nanoparticles to construct an efficient heat conduction path. At the same time, SiO2 nanoparticles and porous hollow SiO2 structures form a rough micro-nanostructure on the coating surface, increasing the thickness of the air layer on the coating surface and improving super-hydrophobic properties. Therefore, the coating is expected to be widely used in multiple fields such as electromagnetic shielding, thermal management, waterproofing and anti-fouling, and has important practical value and far-reaching economic and social significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of the microscopic morphology of the 1-BNNS / C / SiO2 composite filler prepared by the present invention.

[0029] Figure 2 This is a schematic diagram of the microscopic morphology of the 2-BNNS / C / SiO2 composite filler prepared by the present invention.

[0030] In the figure, 1-BNNS, 2-carbon nanoparticles, 3-SiO2 nanoparticles, 4-porous SiO2 microspheres DETAILED DESCRIPTION

[0031] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] The technical solution adopted by the present invention is a method for preparing a wave-absorbing and heat-conducting super-hydrophobic anti-corrosion coating, which is specifically implemented by the following steps:

[0033] Step 1, Boron Nitride Nanosheets (BNNS):

[0034] Boron nitride particles were mixed with isopropyl alcohol and ball-milled at a ball-to-material ratio of 80:1 to 100:1, a reagent-to-material ratio of 50:1 to 60:1, a rotation speed of 400 to 500 rpm, and a ball-milling time of 8 to 12 hours. The mixture was then sonicated for 30 minutes using an ultrasonic cell disruptor, centrifuged at 2000 to 3000 rpm for 15 to 30 minutes, and filtered. The mixture was then washed three times with deionized water and anhydrous ethanol, respectively, and freeze-dried for 6 hours to obtain BNNS.

[0035] Step 2, loading carbon nanoparticles;

[0036] The BNNS obtained in step 1 and a water-soluble polymer are added to deionized water in a mass ratio of 1:5 to 1:10, wherein the mass ratio of the water-soluble polymer to deionized water is 1:30 to 1:50, and the water-soluble polymer is any one of polyvinyl alcohol, sucrose, glucose, chitosan, etc., heated in a water bath at 80°C to 90°C with stirring for 1h to 2h, dried at 80°C for 8h to 12h, and then calcined at 800°C to 1000°C at 3°C / min under a nitrogen atmosphere and kept warm for 2h to 4h to obtain a BNNS / C composite material.

[0037] Step 3: Construct a sandwich structure BNNS / C / SiO2 composite material:

[0038] The BNNS / C composite material obtained in step 2 was ultrasonically dispersed in a mixed solution of anhydrous ethanol and deionized water at a concentration of 0.01 g / mL to 0.02 g / mL, wherein the volume ratio of anhydrous ethanol to deionized water was 3:1 to 6:1, and then N, N, N', N'-tetramethyl-1,4-butanediamine (TMBDM), tetraethyl orthosilicate (TEOS), and hexamethyldisilazane (HMDS) were added in sequence, and the volume ratios of TMBDM, HMDS, TEOS and deionized water were 1:80 to 1:20, 1:10 to 1:30, and 1:1 to 1:3, respectively. The reaction was stirred at room temperature for 4 to 8 hours, centrifuged at a speed of 2000 to 3000 rpm for 15 to 30 minutes, separated, washed three times with ethanol and deionized water, and dried at 60 to 80°C for 6 to 12 hours to obtain a sandwich structure 1-BNNS / C / SiO2 composite material.

[0039] Step 4: Preparation of porous hollow SiO2-coated BNNS / C composite material:

[0040] The BNNS / C obtained in step 2 is ultrasonically dispersed in a mixed solution of anhydrous ethanol and deionized water, wherein the concentration of BNNS / C in the mixed solution of anhydrous ethanol and deionized water is 0.01 g / mL to 0.02 g / mL, and the volume ratio of anhydrous ethanol to deionized water is 1:2 to 1:4. Subsequently, hexadecyltrimethylammonium bromide (CTAB) and ammonia water are added and stirred evenly, the mass ratio of BNNS / C to CTAB is 1:3 to 1:5, and the volume ratio of ammonia water to anhydrous ethanol is 1:60 to 1:80; resorcinol is added under continuous stirring and reacted for 30 minutes, and then TEOS and formaldehyde are added dropwise, and the mass ratio of resorcinol to CTAB is 1:3 to 1:5. The ratio is 1:2 to 2:1, the volume ratio of TEOS to anhydrous ethanol is 1:5 to 1:10, and the volume ratio of formaldehyde to anhydrous ethanol is 1:10 to 1:20, and the reaction is stirred at room temperature for 4h to 6h; the reaction product is centrifuged at a speed of 2000rpm to 3000rpm for 15min to 30min, washed with anhydrous ethanol and deionized water, dried at 60℃ to 80℃ for 6h to 12h, and calcined in a muffle furnace at a heating rate of 5℃ / min, the temperature is 550℃, and the holding time is 4h to 6h to obtain a porous hollow SiO2-coated BNNS / C composite material (2-BNNS / C / SiO2).

[0041] Step 5: Preparation of a wave-absorbing and heat-conducting super-hydrophobic anti-corrosion coating

[0042] The 1-BNNS / C / SiO2 composite material obtained in step 3 and the 2-BNNS / C / SiO2 composite material obtained in step 4 are mixed with polyurethane in a mass ratio of 1:5 to 1:1, and the filling rate of the total mass of the two composite materials in the polyurethane is 10% to 60%. The mixture is stirred for 20 min to 60 min at a speed of 500 rpm to 800 rpm by a stirrer, and then ultrasonically dispersed for 15 min to 30 min, and the above stirring and ultrasonic dispersion are repeated 2 to 4 times; a curing agent is added, wherein the curing agent is one of a trimer of toluene diisocyanate (TDI), 1,6-hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI), and the mass ratio of the curing agent to the total mass of the 1-BNNS / C / SiO2 composite material and the 2-BNNS / C / SiO2 composite material is 1:500 to 1:1000. After stirring for 1 min to 3 min, it is applied to an aluminum plate, and after complete curing, a wave-absorbing and heat-conducting super-hydrophobic anti-corrosion coating is obtained.

[0043] The present invention uses fine ball milling technology to peel off boron nitride to prepare BNNS with high specific surface area, providing a basis for subsequent functionalization; water-soluble polymer precursors are used to prepare carbon nanoparticles, and they are tightly attached to the surface of BNNS with SiO2 nanoparticles to construct an efficient conductive and thermal conduction network, enhancing wave absorption and surface roughness, and using CTAB as a template agent to control the proportion of each raw material to form a hollow porous SiO2 microsphere-coated BNNS / C structure, which increases the specific surface area of ​​the material. The unique pores also optimize the impedance matching of the material and achieve effective scattering and absorption of electromagnetic waves; the mixed dual-structure BNNS / C / SiO2 is used as polyurethane filler to optimize the filling rate and construct a multi-level composite structure, which significantly improves the wave absorption, thermal conductivity and super-hydrophobicity properties to meet the needs of high performance and diversity.

[0044] The present invention provides a wave-absorbing and heat-conducting super-hydrophobic anti-corrosion coating. Carbon nanoparticles are tightly attached to the surface of BNNS to construct an efficient conductive network, accelerate electron migration and polarization, and BNNS acts as an impedance matching layer to optimize electromagnetic absorption. By introducing porous SiO2 microspheres, not only the specific surface area is increased, but also its unique pores are used to achieve effective scattering and absorption of electromagnetic waves. Furthermore, BNNS with excellent thermal conductivity is combined with carbon nanoparticles and SiO2 nanoparticles to construct an efficient heat conduction path. At the same time, SiO2 nanoparticles and porous hollow SiO2 structures form a rough micro-nano structure on the coating surface, increase the thickness of the air layer on the coating surface, and enhance super-hydrophobic performance. Therefore, the coating is expected to be widely used in multiple fields such as electromagnetic shielding, thermal management, waterproofing and anti-fouling, and has important practical value.

[0045] Example 1 Preparation of wave-absorbing heat-conducting super-hydrophobic anti-corrosion coating 1

[0046] First, 3 g of boron nitride particles, 150 g of isopropanol, and 240 g of ball milling beads were weighed and placed in a ball mill. The mixture was ball milled at 400 rpm for 8 h. Then, an ultrasonic cell disruptor was used for 30 min. The mixture was centrifuged at 2000 rpm for 15 min. The supernatant was vacuum filtered, washed three times with deionized water and anhydrous ethanol, and freeze-dried for 6 h to obtain BNNS.

[0047] 0.5 g of BNNS and 2.5 g of polyvinyl alcohol were weighed and added to 125 mL of deionized water, heated in a water bath at 80 °C and stirred for 1 h; then dried at 80 °C for 8 h to obtain a BNNS / C precursor; calcined in a nitrogen atmosphere at a heating rate of 3 °C / min to 800 °C, and kept warm for 2 h to obtain a BNNS / C composite material.

[0048] 0.7 g of BNNS / C composite material was weighed and ultrasonically dispersed in a mixed solution of 60 mL of anhydrous ethanol and 10 mL of deionized water. Subsequently, 0.125 mL of TMBDM, 0.333 mL of HMDS and 3.3 mL of LTEOS were added, stirred at room temperature, and reacted for 4 hours. The obtained solution was then centrifuged at 2000 rpm for 15 minutes. After separating the precipitate, it was washed three times with anhydrous ethanol and deionized water, and dried at 60°C for 6 hours to obtain a sandwich structure 1-BNNS / C / SiO2 composite material.

[0049] 0.5 g BNNS / C composite material was weighed and ultrasonically dispersed in a mixed solution of 10 mL anhydrous ethanol and 40 mL deionized water, and then 1.5 g CTAB and 0.125 mL ammonia water were added. After stirring evenly, 0.75 g resorcinol was added under continuous stirring and reacted for 30 min. Then 1 mL LTEOS and 0.5 mL formaldehyde were added and stirred continuously at room temperature for 4 h. The reaction product was centrifuged at 2000 rpm for 15 min, washed with anhydrous ethanol and deionized water, dried at 60 ° C for 6 h, and calcined in a muffle furnace at a heating rate of 5 ° C / min, the temperature was 550 ° C, and the holding time was 4 h to obtain a porous hollow SiO2-coated BNNS / C composite material (2-BNNS / C / SiO2).

[0050] Weigh 0.33g of 1-BNNS / C / SiO2 and 1.67g of 2-BNNS / C / SiO2 and mix them with 20g of polyurethane. Stir in a blender at 500rpm for 20min, then ultrasonically disperse for 15min. Repeat the above stirring and ultrasonic steps twice. Add 0.002g of TDI, stir for 1min, and evenly apply it on an aluminum plate. After complete curing, a wave-absorbing, heat-conducting, super-hydrophobic anti-corrosion coating is obtained.

[0051] Example 2 Preparation of BNNS / C / SiO2 / Fe3O4 composite filler 2

[0052] First, 3 g of boron nitride particles, 180 g of isopropanol, and 300 g of ball milling beads were weighed and placed in a ball mill. The mixture was ball milled at 500 rpm for 12 h. Then, an ultrasonic cell disruptor was used for 30 min. The mixture was centrifuged at 3000 rpm for 30 min. The supernatant was vacuum filtered, washed three times with deionized water and anhydrous ethanol, and freeze-dried for 6 h to obtain BNNS.

[0053] 0.5 g BNNS and 5 g sucrose were weighed and added to 150 mL deionized water, heated in a water bath at 90 ° C and stirred for 2 h; then dried at 80 ° C for 12 h to obtain a BNNS / C precursor; calcined at a heating rate of 3 ° C / min in a nitrogen atmosphere, the calcination temperature was 1000 ° C, and kept warm for 4 h to obtain a BNNS / C composite material.

[0054] 0.8 g of BNNS / C composite material was weighed and ultrasonically dispersed in a mixed solution of 30 mL of anhydrous ethanol and 10 mL of deionized water. Subsequently, 0.5 mL of TMBDM, 1 mL of HMDS and 10 mL of LTEOS were added, stirred at room temperature, and reacted for 8 h. The obtained solution was then centrifuged at 3000 rpm for 30 min. After separating the precipitate, it was washed three times with anhydrous ethanol and deionized water, and dried at 80 °C for 12 h to obtain a sandwich structure 1-BNNS / C / SiO2 composite material.

[0055] 0.6 g BNNS / C composite material was weighed and ultrasonically dispersed in a mixed solution of 10 mL anhydrous ethanol and 20 mL deionized water, and then 3 g CTAB and 0.167 mL ammonia water were added. After stirring evenly, 6 g resorcinol was added under continuous stirring and reacted for 30 minutes, followed by 2 mL LTEOS and 1 mL formaldehyde. The reaction was stirred continuously at room temperature for 6 hours; the reaction product was centrifuged at 3000 rpm for 30 minutes, washed with anhydrous ethanol and deionized water, dried at 80 ° C for 12 hours, and calcined in a muffle furnace at a heating rate of 5 ° C / min, the temperature was 550 ° C, and the holding time was 6 hours to obtain a porous hollow SiO2-coated BNNS / C composite material (2-BNNS / C / SiO2).

[0056] 2g of 1-BNNS / C / SiO2 and 3g of 2-BNNS / C / SiO2 were weighed and mixed with 20g of polyurethane. The mixture was stirred at 800 rpm for 60min in a blender and then ultrasonically dispersed for 30min. The above stirring and ultrasonic steps were repeated 4 times. 0.024g of HDI was added, stirred for 3min, and then evenly applied to an aluminum plate. After complete curing, a wave-absorbing, heat-conductive, super-hydrophobic anti-corrosion coating was obtained.

[0057] Example 3 Preparation of BNNS / C / SiO2 / Fe3O4 composite filler 3

[0058] First, 3 g of boron nitride particles, 160 g of isopropyl alcohol, and 260 g of ball milling beads were weighed and placed in a ball mill. The mixture was ball milled at 450 rpm for 10 h, then ultrasonicated using an ultrasonic cell disruptor for 30 min. The mixture was centrifuged at 2500 rpm for 20 min, and the supernatant was vacuum filtered. The mixture was washed three times with deionized water and anhydrous ethanol, respectively, and freeze-dried for 6 h to obtain BNNS.

[0059] 0.5 g BNNS and 3 g glucose were weighed and added to 120 mL deionized water, heated in a water bath at 85 °C with stirring for 1.5 h; then dried at 85 °C for 10 h to obtain a BNNS / C precursor; calcined in a nitrogen atmosphere at a heating rate of 3 °C / min to a calcination temperature of 900 °C and kept warm for 3 h to obtain a BNNS / C composite material.

[0060] 0.5 g of BNNS / C composite material was weighed and ultrasonically dispersed in a mixed solution of 40 mL of anhydrous ethanol and 10 mL of deionized water. Subsequently, 0.3 mL of TMBDM, 0.5 mL of HMDS and 5 mL of LTEOS were added, stirred at room temperature, and reacted for 6 h. The obtained solution was then centrifuged at 2500 rpm for 20 min. After separating the precipitate, it was washed three times with anhydrous ethanol and deionized water, and dried at 70 °C for 10 h to obtain a sandwich structure 1-BNNS / C / SiO2 composite material.

[0061] 0.4 g BNNS / C composite material was weighed and ultrasonically dispersed in a mixed solution of 10 mL anhydrous ethanol and 30 mL deionized water, and then 1.6 g CTAB and 0.15 mL ammonia water were added. After stirring evenly, 1.6 g resorcinol was added under continuous stirring and reacted for 30 minutes, followed by 1.5 mL LTEOS and 0.7 mL formaldehyde. The reaction was stirred continuously at room temperature for 5 hours; the reaction product was centrifuged at a speed of 2500 rpm for 20 minutes, washed with anhydrous ethanol and deionized water, dried at 70 ° C for 10 hours, and calcined in a muffle furnace at a heating rate of 5 ° C / min, the temperature was 550 ° C, and the holding time was 5 hours to obtain a porous hollow SiO2-coated BNNS / C composite material (2-BNNS / C / SiO2).

[0062] Weigh 3g of 1-BNNS / C / SiO2 and 3g of 2-BNNS / C / SiO2 and mix them with 20g of polyurethane. Stir them in a blender at 600rpm for 40min and then ultrasonically disperse them for 20min. Repeat the above stirring and ultrasonic steps 3 times. Add 0.008g of IPDI trimer, stir for 2min and evenly apply it on an aluminum plate. After complete curing, a wave-absorbing and heat-conductive super-hydrophobic anti-corrosion coating is obtained.

[0063] Example 4 Preparation of BNNS / C / SiO2 / Fe3O4 composite filler 4

[0064] First, 3 g of boron nitride particles, 170 g of isopropanol, and 270 g of ball milling beads were weighed and placed in a ball mill. The mixture was ball milled at 400 rpm for 10 h. Then, an ultrasonic cell disruptor was used for 30 min. The mixture was centrifuged at 2500 rpm for 25 min. The supernatant was vacuum filtered, washed three times with deionized water and anhydrous ethanol, and freeze-dried for 6 h to obtain BNNS.

[0065] 0.5 g BNNS and 4 g chitosan were weighed and added to 150 mL deionized water, heated in a water bath at 80 °C with stirring for 2 h; then dried at 80 °C for 10 h to obtain a BNNS / C precursor; calcined under a nitrogen atmosphere at a heating rate of 3 °C / min to a calcination temperature of 950 °C, and kept warm for 3 h to obtain a BNNS / C composite material.

[0066] 0.75 g of BNNS / C composite material was weighed and ultrasonically dispersed in a mixed solution of 40 mL of anhydrous ethanol and 10 mL of deionized water. Subsequently, 0.25 mL of TMBDM, 0.8 mL of HMDS and 8 mL of LTEOS were added, stirred at room temperature, and reacted for 5 h. The obtained solution was then centrifuged at 3000 rpm for 30 min. After separating the precipitate, it was washed three times with anhydrous ethanol and deionized water, and dried at 80 °C for 10 h to obtain a sandwich structure 1-BNNS / C / SiO2 composite material.

[0067] 0.75g BNNS / C composite material was weighed and ultrasonically dispersed in a mixed solution of 10mL anhydrous ethanol and 40mL deionized water, and then 3g CTAB and 0.14mL ammonia water were added. After stirring evenly, 5g resorcinol was added under continuous stirring and reacted for 30min, followed by 1.5mL LTEOS and 0.8mL formaldehyde. The reaction was stirred continuously at room temperature for 5h. The reaction product was centrifuged at 3000rpm for 30min, washed with anhydrous ethanol and deionized water, dried at 70℃ for 12h, and calcined in a muffle furnace at a heating rate of 5℃ / min, a temperature of 550℃, and a holding time of 6h to obtain a porous hollow SiO2-coated BNNS / C composite material (2-BNNS / C / SiO2).

[0068] 4 g of 1-BNNS / C / SiO2 and 6 g of 2-BNNS / C / SiO2 were weighed and mixed with 20 g of polyurethane. The mixture was stirred at 600 rpm for 50 min and then ultrasonically dispersed for 20 min. The above stirring and ultrasonic steps were repeated 4 times. 0.003 g of HDI was added, stirred for 3 min, and then evenly applied to an aluminum plate. After complete curing, a wave-absorbing, heat-conducting, super-hydrophobic anti-corrosion coating was obtained.

[0069] Comparative Example 1

[0070] The only difference from Example 3 is that the 1-BNNS / C / SiO2 composite material is not added in step 5.

[0071] Comparative Example 2

[0072] The only difference from Example 3 is that the 2-BNNS / C / SiO2 composite material is not added in step 5.

[0073] Comparative Example 3

[0074] The only difference from Example 3 is that no carbon nanoparticles are loaded, and BNNS is directly used for the subsequent steps.

[0075] Table 1 is a comparison of the wave absorption, thermal conductivity and super hydrophobic performance of the wave absorbing and heat conducting super hydrophobic anticorrosion coating, the coating of Comparative Example 1, the coating of Comparative Example 2 and the coating of Comparative Example 3 in Example 3. As can be seen from Table 1, the wave absorbing and heat conducting super hydrophobic anticorrosion coating has the best comprehensive performance in Example 3. The coating of Comparative Example 1 lacks 1-BNNS / C / SiO2 composite material, which seriously affects the rough surface micro-nano structure of the construction. 1-BNNS / C / SiO2 composite material is lacking in Comparative Example 2, and porous SiO2 microspheres extend the electromagnetic wave propagation path, so the wave absorbing performance of the material is significantly affected. In Comparative Example 3, the coating lacks carbon nanoparticles, which reduces the effective channel for heat transfer and weakens the dissipation capacity of electromagnetic waves, and its thermal conductivity and wave absorbing performance are significantly reduced. In the wave-absorbing and heat-conducting super-hydrophobic anti-corrosion coating in Example 3, carbon nanoparticles and BNNS can construct an efficient conductive network and heat conduction path. The loading of nano-SiO2 increases the roughness of the material, and the porous SiO2 microspheres promote the scattering and absorption of electromagnetic waves. At the same time, the composite material also has a complex micro-nano structure, which significantly improves the super-hydrophobic performance. Therefore, it has the best comprehensive performance and is better than all comparative examples.

[0076] Table 1 Comparison of the wave absorbing, thermal conductive and super hydrophobic properties of the wave absorbing and thermal conductive super hydrophobic anti-corrosion coating in Example 3, the coating in Comparative Example 1, the coating in Comparative Example 2 and the coating in Comparative Example 3.

[0077]

[0078] Figure 1 Schematic diagram of the microscopic morphology of 1-BNNS / C / SiO2 prepared by the present invention. Figure 1 It can be seen that carbon nanoparticles and SiO2 nanoparticles are uniformly loaded on the surface of BNNS. Figure 2 Schematic diagram of the microscopic morphology of 2-BNNS / C / SiO2 prepared by the present invention. Figure 2 It can be seen that the hollow porous SiO2 microspheres encapsulate the BNNS uniformly loaded with carbon nanoparticles.

[0079] The above specific embodiments are used to illustrate the present invention rather than to limit the present invention. Any modifications and changes made to the present invention within the spirit of the present invention and the protection scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A method for preparing a wave-absorbing and heat-conducting super-hydrophobic anti-corrosion coating, characterized in that: Please follow the steps below to implement: Step 1, Boron Nitride Nanosheets (BNNS) Boron nitride particles were mixed with isopropanol and ball-milled, then ultrasonicated for 30 min using an ultrasonic cell disruptor, centrifuged and filtered, washed three times with deionized water and ethanol respectively, and freeze-dried for 6 h to obtain BNNS. Step 2: Loading carbon nanoparticles The BNNS obtained in step 1 and the water-soluble polymer were added to deionized water, heated in a water bath, and stirred. After drying, the mixture was calcined under a nitrogen atmosphere to obtain a BNNS / C composite material. Step 3: Constructing a sandwich structure BNNS / C / SiO2 composite material The BNNS / C composite material obtained in step 2 was ultrasonically dispersed in a mixed solution of anhydrous ethanol and deionized water, and then N, N, N', N'-tetramethyl-1, 4-butanediamine (TMBDM), tetraethyl orthosilicate (TEOS), and hexamethyldisilazane (HMDS) were added in sequence. The mixture was stirred at room temperature for reaction. After centrifugation, the mixture was washed three times with ethanol and deionized water, and finally dried to obtain a sandwich structure 1-BNNS / C / SiO2 composite material. Step 4: Preparation of porous hollow SiO2-coated BNNS / C composite materials The BNNS / C obtained in step 2 was ultrasonically dispersed in a mixed solution of anhydrous ethanol and deionized water, followed by the addition of cetyltrimethylammonium bromide (CTAB) and ammonia water and stirred evenly; resorcinol was added under continuous stirring for 30 minutes, and then TEOS and formaldehyde were added dropwise and stirred at room temperature for reaction; the reaction product was centrifuged, washed with anhydrous ethanol and deionized water, dried, and calcined in a muffle furnace to obtain a porous hollow SiO2-coated BNNS / C composite material 2-BNNS / C / SiO2; Step 5: Preparation of a wave-absorbing and heat-conducting super-hydrophobic anti-corrosion coating The 1-BNNS / C / SiO2 composite material obtained in step 3 and the 2-BNNS / C / SiO2 composite material obtained in step 4 are mixed with polyurethane, mixed evenly by a stirrer and then ultrasonically dispersed, and the above stirring and ultrasonic dispersion are repeated multiple times; a curing agent is added, stirred evenly and then applied to an aluminum plate, and after complete curing, a wave-absorbing and heat-conducting super-hydrophobic anti-corrosion coating is obtained; in the step 5, the mass ratio of the 1-BNNS / C / SiO2 composite material to the 2-BNNS / C / SiO2 composite material is 1:5~1:

1.

2. The method for preparing a wave-absorbing heat-conducting super-hydrophobic anti-corrosion coating according to claim 1, wherein: In the step 1, the ball-to-material ratio is 80:1-100:1, the agent-to-material ratio is 50:1-60:1, the rotation speed is 400r / min-500r / min, the ball milling time is 8h-12h; the centrifugal speed is 2000rpm-3000rpm, and the time is 15min-30min.

3. The method for preparing a wave-absorbing heat-conducting super-hydrophobic anti-corrosion coating according to claim 1, wherein: In step 2, the mass ratio of BNNS to water-soluble polymer is 1:5-1:10, the mass ratio of water-soluble polymer to deionized water is 1:30-1:50, the stirring temperature is 80° C.-90° C., and the stirring time is 1 h-2 h.

4. The method for preparing a wave-absorbing heat-conducting super-hydrophobic anti-corrosion coating according to claim 1, wherein: The water-soluble polymer is any one of polyvinyl alcohol, sucrose, glucose and chitosan.

5. The method for preparing a wave-absorbing heat-conducting super-hydrophobic anti-corrosion coating according to claim 1, wherein: In step 3, the concentration of BNNS / C in the mixed solution of anhydrous ethanol and deionized water is 0.01 g / mL to 0.02 g / mL, the volume ratio of anhydrous ethanol to deionized water is 3:1 to 6:1, and the volume ratios of TMBDM, HMDS, and TEOS to deionized water are 1:80 to 1:20, 1:10 to 1:30, and 1:1 to 1:3, respectively.

6. The method for preparing a wave-absorbing heat-conducting super-hydrophobic anti-corrosion coating according to claim 1, wherein: In step 3, the reaction time is 4 h to 8 h, the centrifugal speed is 2000 rpm to 3000 rpm, the centrifugal time is 15 min to 30 min, the drying temperature is 60° C. to 80° C., and the drying time is 6 h to 12 h.

7. The method for preparing a wave-absorbing heat-conducting super-hydrophobic anti-corrosion coating according to claim 1, wherein: In step 4, the concentration of BNNS / C in the mixed solution of anhydrous ethanol and deionized water is 0.01 g / mL to 0.02 g / mL, the volume ratio of anhydrous ethanol to deionized water is 1:2 to 1:4, the mass ratio of BNNS / C to CTAB is 1:3 to 1:5, the volume ratio of ammonia water to anhydrous ethanol is 1:60 to 1:80, the mass ratio of resorcinol to CTAB is 1:2 to 2:1, the volume ratio of TEOS to anhydrous ethanol is 1:5 to 1:10, and the volume ratio of formaldehyde to anhydrous ethanol is 1:10 to 1:

20.

8. The method for preparing a wave-absorbing heat-conducting super-hydrophobic anti-corrosion coating according to claim 1, wherein: In step 4, the reaction time is 4 h to 6 h, the centrifugal speed is 2000 rpm to 3000 rpm, the time is 15 min to 30 min, the drying temperature is 60° C. to 80° C., and the drying time is 6 h to 12 h.

9. The method for preparing a wave-absorbing heat-conducting super-hydrophobic anti-corrosion coating according to claim 1, wherein: In step 5, the stirrer speed is 500 rpm to 800 rpm, the stirring time is 20 min to 60 min, the ultrasonic time is 15 min to 30 min, and the number of repetitions is 2 to 4 times.

10. The wave-absorbing and heat-conducting super-hydrophobic anti-corrosion coating according to any one of claims 1 to 9, characterized in that: The coating consists of a polyurethane matrix and two BNNS / C / SiO2 composite materials with different structures. The structure of the 1-BNNS / C / SiO2 composite material is: carbon nanoparticles are uniformly loaded on the surface of BNNS, and then SiO2 microspheres are uniformly grown on its surface; the structure of the 2-BNNS / C / SiO2 composite material is: porous mesoporous SiO2 microspheres wrap the BNNS uniformly loaded with carbon nanoparticles.

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