Aluminum alloy composite material based on corrosion-resistant coating and preparation method thereof

Abstract

The present invention relates to the technical field of coatings, and discloses an aluminum alloy composite material based on a corrosion-resistant coating and a preparation method thereof. Preparation steps: S1: taking catechin aldehyde and 4-fluoro-1-aminonaphthalene, adding them to anhydrous methanol and stirring evenly, heating to reflux reaction, removing the solvent, and obtaining a fluorine-containing Schiff base; taking 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 1,4-dioxane, and a fluorine-containing Schiff base, heating and stirring the reaction, removing the solvent, and obtaining a flame retardant; S2: stirring and dispersing epoxy resin, reactive diluent, modified filler, flame retardant, curing agent, imidazole, leveling agent, and photoinitiator evenly to obtain a corrosion-resistant coating; S3: applying the corrosion-resistant coating to the surface of the aluminum alloy material, curing, drying and cooling, and obtaining an aluminum alloy composite material with a corrosion-resistant coating on the surface.

Description

Technical Field

[0001] The invention relates to the technical field of coatings and discloses an aluminum alloy composite material based on a corrosion-resistant coating and a preparation method thereof. Background Art

[0002] Aluminum alloys, with their advantages of high strength, low density, and excellent processability, are widely used in aerospace, transportation, and other fields. However, aluminum alloys are susceptible to corrosion in humid environments, seriously affecting their service life. Existing technologies often use organic coatings to protect aluminum alloys, isolating the metal substrate from the surrounding media and thus slowing the corrosion process.

[0003] Epoxy resin-based coatings have strong adhesion to aluminum alloy surfaces and possess good chemical stability and mechanical strength. However, due to their poor flame retardancy, they cannot prevent the spread of fire. Furthermore, their insufficient toughness makes them susceptible to crack propagation when impacted, leading to coating failure. Therefore, research on aluminum alloy composite materials with coatings that exhibit corrosion resistance, flame retardancy, and impact resistance, as well as methods for their preparation, is of great significance. Summary of the Invention

[0004] The object of the present invention is to provide an aluminum alloy composite material based on a corrosion-resistant coating and a preparation method thereof, so as to solve the problems raised in the above background technology.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: A method for preparing an aluminum alloy composite material based on a corrosion-resistant coating, comprising the following steps: S1: taking catechin aldehyde and 4-fluoro-1-aminonaphthalene, adding them to anhydrous methanol and stirring evenly, heating and refluxing the mixture, removing the solvent to obtain a fluorine-containing Schiff base; taking 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 1,4-dioxane, and a fluorine-containing Schiff base, heating and stirring the mixture to react, and removing the solvent to obtain a flame retardant;

[0006] S2: stirring and dispersing epoxy resin, reactive diluent, modified filler, flame retardant, curing agent, imidazole, leveling agent, and photoinitiator to obtain a corrosion-resistant coating;

[0007] S3: applying the corrosion-resistant coating to the surface of the aluminum alloy material, solidifying, drying and cooling, and obtaining an aluminum alloy composite material having the corrosion-resistant coating on the surface.

[0008] More optimally, the fluorinated Schiff base comprises the following raw materials, in parts by mass: 1 to 1.5 parts of catechin aldehyde, 1.5 to 2 parts of 4-fluoro-1-aminonaphthalene, and 20 to 30 parts of anhydrous methanol; the flame retardant comprises the following raw materials, in parts by mass: 2 to 2.5 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 20 to 50 parts of 1,4-dioxane, and 2 to 4 parts of fluorinated Schiff base.

[0009] More optimally, the corrosion-resistant coating includes the following raw materials, calculated by mass: 35~45 parts of epoxy resin, 8~12 parts of active diluent, 25~30 parts of modified filler, 5~8 parts of flame retardant, 6~10 parts of curing agent (small molecule curing agent, preferably m-phenylenediamine), 1~2 parts of imidazole, 0.5~1 part of leveling agent, and 0.1~0.2 part of photoinitiator.

[0010] More optimally, the preparation of the modified filler includes the following steps: taking carboxylated carbon nanotubes, adding thionyl chloride and N,N-dimethylformamide under nitrogen protection, stirring for 5-6 minutes, ultrasonically dispersing at 20-30°C for 2-3 hours, refluxing for 20-25 hours, filtering the solid, washing and drying to obtain acyl chloride carbon nanotubes;

[0011] Add acyl chloride carbon nanotubes to tetrahydrofuran and stir evenly, add trihydroxy heptaoctyl poss, stir and react at 40-50°C for 70-75h, filter and collect the solid, wash and dry to obtain a composite filler;

[0012] The composite filler is added to the ethanol-water mixed solution and stirred evenly, 3-(2,3-epoxypropoxy)propyltrimethoxysilane is added and mixed evenly, and the mixture is stirred at 60-70° C. for 4-8 hours, and the solid is filtered and washed to obtain the epoxidized composite filler;

[0013] Add the epoxidized composite filler to benzene, add hydroxyl-terminated methyl vinyl silicone oil and triethanolamine, stir evenly, stir and react at 100-120°C under nitrogen protection for 2-3 hours, add hydroxyl fluorosilicone oil, keep warm and stir for 2-3 hours, remove the solvent and catalyst to obtain the modified filler.

[0014] More optimally, the chlorinated carbon nanotubes include the following raw materials, calculated by weight: 0.3-0.5 parts of carboxylated carbon nanotubes, 50-60 parts of thionyl chloride, and 1-2 parts of N,N-dimethylformamide;

[0015] The composite filler comprises the following raw materials, calculated by weight: 1-2 parts of acyl chloride carbon nanotubes and 1-2 parts of trihydroxy heptaoctyl poss.

[0016] More optimally, the epoxidized composite filler comprises the following raw materials, calculated by weight: 10-15 parts of composite filler, 1-2 parts of 3-(2,3-epoxypropoxy)propyltrimethoxysilane;

[0017] The modified filler comprises the following raw materials, calculated by mass: 10-15 parts of epoxidized composite filler, 2-4 parts of hydroxyl-terminated vinyl silicone oil, 0.1-0.2 parts of triethanolamine, and 5-8 parts of hydroxyl fluorosilicone oil.

[0018] More optimally, the curing conditions are: UV light irradiation for 1~2 hours, curing at 80~100℃ for 3~4 hours, and curing at 120~130℃ for 2~3 hours.

[0019] More optimally, the active diluent is allyl glycidyl ether.

[0020] More optimally, the aluminum alloy material includes the following components: 0.1~0.3% Cu, 0.3~0.5% Mn, 0.2~0.4% Fe, 0.2~0.4% Si, 0.6~1% Mg, 0.01~0.02% Ti, 0.03~0.05% Zn, 0.05~0.25% Cr, and the balance is Al and unavoidable impurities.

[0021] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: (1) a fluorine-containing Schiff base is prepared by reacting catechol and 4-fluoro-1-aminonaphthalene, and then 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is introduced by reacting the fluorine-containing Schiff base with PH to obtain a flame retardant; wherein the fluorine element can effectively improve the corrosion resistance of the epoxy resin-based material, and the naphthalene ring can increase the rigid structure, which helps to improve the overall heat resistance and strength; at the same time, the phenolic hydroxyl structure contained in the phenolic hydroxyl group can participate in curing and improve the compatibility of the flame retardant with the epoxy resin;

[0022] (2) After the carbon nanotubes are chlorinated, they are connected with trihydroxy heptaoctyl poss, and then modified with an epoxy silane coupling agent, and grafted with vinyl-containing silicone oil and fluorine-containing silicone oil; after cross-linking, the two inorganic fillers with different structures can improve the surface morphology and penetrate into the resin matrix by anchoring to improve the bonding strength; the introduced organic silicon segment has high thermal stability and can also improve the compatibility of epoxy resin and composite filler. Due to the flexibility of the silicone oil itself, it can alleviate the problem of excessive brittleness caused by excessive rigid structure and enhance the overall impact strength. Therefore, the amount of flame retardant and modified filler added needs to be controlled to balance rigidity and flexibility; at the same time, due to the presence of fluorine element, the corrosion resistance is further improved, and the affinity with the flame retardant can also be improved; the modified filler contains a double bond structure, which helps in the subsequent steps of curing and improving the overall compatibility;

[0023] (3) Allyl glycidyl ether is selected as the active diluent to introduce double bonds, which helps with subsequent curing and helps improve compatibility with modified fillers;

[0024] (4) A step-by-step curing process is used. First, ultraviolet light is used to pre-crosslink the double bonds in the system. Then the temperature is gradually increased to allow the groups in the curing agent and flame retardant to react with the epoxy groups. This gradual curing can reduce internal stress, improve the quality of the coating, and further improve its impact strength and corrosion resistance. DETAILED DESCRIPTION

[0025] 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.

[0026] It should be noted that the purchasers of all raw materials involved in the present invention are not particularly restricted, and illustratively include: ethanol (CAS: 64-17-5); catechin aldehyde (CAS: 139-85-5); 4-fluoro-1-aminonaphthalene (CAS: 438-32-4); 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (CAS: 35948-25-5); 1,4-dioxane (CAS: 123-91-1); trihydroxy heptaoctyl poss (JH-P302); carboxylated carbon nanotubes (Kramer 180117142215); N,N-dimethylformamide (CAS: 68-12-2); 3-(2,3-epoxypropoxy)propyltrimethoxysilane (CAS: 2530-83-8); hydroxyl-terminated methyl vinyl silicone oil (IOTA 1203V); triethanolamine (anhydrous tin tetrachloride); hydroxy fluorosilicone oil (TPD-FS8014); epoxy resin (E51, Jinan Shanhai Chemical); allyl glycidyl ether (CAS: 106-92-3); curing agent (m-phenylenediamine); imidazole (CAS: 288-32-4); sodium polyacrylate (S30249, Yuanye); photoinitiator (CAS: 119-61-9);

[0027] Unless otherwise specified, the following are parts by mass and mass ratios;

[0028] The aluminum alloy material includes the following components: 0.2% Cu, 0.4% Mn, 0.3% Fe, 0.3% Si, 1% Mg, 0.01% Ti, 0.03% Zn, 0.15% Cr, and the balance is Al and unavoidable impurities;

[0029] Example 1: S1: 1.4 parts of catechin aldehyde and 1.6 parts of 4-fluoro-1-aminonaphthalene were added to 25 parts of anhydrous methanol, stirred evenly, heated to reflux for 8 hours, and the solvent was removed to obtain a fluorinated Schiff base; 2.2 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 40 parts of 1,4-dioxane, and 3 parts of a fluorinated Schiff base were added, heated to 70°C, stirred for reaction for 6 hours, and the solvent was removed to obtain a flame retardant;

[0030] S2: Take 0.5 parts of carboxylated carbon nanotubes, add 60 parts of thionyl chloride and 1 part of N,N-dimethylformamide under nitrogen protection, stir for 5 minutes, ultrasonically disperse at 30°C for 3 hours, reflux at 70°C for 24 hours, filter and take the solid, wash and dry to obtain chlorinated carbon nanotubes; take 2 parts of chlorinated carbon nanotubes, add them to 100 parts of tetrahydrofuran and stir evenly, add 1 part of trihydroxy heptaoctyl poss, stir at 50°C for 72 hours, filter and take the solid, wash and dry to obtain a composite filler; add 10 parts of the composite filler to 100 parts of Stirring the mixture of ethanol and water (volume ratio of ethanol to water 7:3) evenly, adding 1 part of 3-(2,3-epoxypropoxy)propyltrimethoxysilane, mixing evenly, stirring and reacting at 70°C for 8 hours, filtering and collecting the solid, and washing to obtain an epoxidized composite filler; adding 12 parts of the epoxidized composite filler to 100 parts of benzene, adding 3 parts of hydroxyl-terminated methyl vinyl silicone oil and 0.01 parts of triethanolamine, stirring and reacting at 120°C under nitrogen protection for 3 hours, adding 6 parts of hydroxyl fluorosilicone oil, continuing to stir and maintain the temperature for 3 hours, removing the solvent and catalyst to obtain a modified filler;

[0031] S3: 40 parts of epoxy resin, 10 parts of active diluent allyl glycidyl ether, 28 parts of modified filler, 6 parts of flame retardant, 8 parts of m-xylenediamine, 1 part of imidazole, 0.5 parts of leveling agent sodium polyacrylate, and 0.1 parts of photoinitiator are placed in a high-speed disperser and stirred and dispersed to obtain a corrosion-resistant coating;

[0032] S4: Apply the corrosion-resistant coating to the surface of the aluminum alloy material with a coating thickness of 25 μm, irradiate with 350 nm ultraviolet light for 1 hour, heat to 80° C. and cure for 4 hours, then cure at 130° C. for 2 hours, dry and cool to obtain an aluminum alloy composite material with a corrosion-resistant coating on the surface.

[0033] Example 2: S1: Take 1 part of catechin aldehyde and 1.5 parts of 4-fluoro-1-aminonaphthalene, add them to 25 parts of anhydrous methanol, stir evenly, heat to reflux for 8 hours, remove the solvent to obtain a fluorinated Schiff base; take 2 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 40 parts of 1,4-dioxane, and 2 parts of a fluorinated Schiff base, heat to 70°C, stir to react for 6 hours, and remove the solvent to obtain a flame retardant;

[0034] S2: Take 0.5 parts of carboxylated carbon nanotubes, add 60 parts of thionyl chloride and 1 part of N,N-dimethylformamide under nitrogen protection, stir for 5 minutes, ultrasonically disperse at 30°C for 3 hours, reflux at 70°C for 24 hours, filter and take the solid, wash and dry to obtain chlorinated carbon nanotubes; take 2 parts of chlorinated carbon nanotubes, add them to 100 parts of tetrahydrofuran and stir evenly, add 1 part of trihydroxy heptaoctyl poss, stir at 50°C for 72 hours, filter and take the solid, wash and dry to obtain a composite filler; add 10 parts of the composite filler to 100 parts of Stirring the mixture of ethanol and water (volume ratio of ethanol to water 7:3) evenly, adding 1 part of 3-(2,3-epoxypropoxy)propyltrimethoxysilane, mixing evenly, stirring and reacting at 70°C for 8 hours, filtering and collecting the solid, and washing to obtain an epoxidized composite filler; adding 12 parts of the epoxidized composite filler to 100 parts of benzene, adding 4 parts of hydroxyl-terminated methyl vinyl silicone oil and 0.01 parts of triethanolamine, stirring and reacting at 110°C under nitrogen protection for 3 hours, adding 6 parts of hydroxyl fluorosilicone oil, continuing to stir and maintain the temperature for 3 hours, removing the solvent and catalyst to obtain a modified filler;

[0035] S3: 38 parts of epoxy resin, 10 parts of active diluent allyl glycidyl ether, 30 parts of modified filler, 8 parts of flame retardant, 8 parts of m-xylenediamine, 1 part of imidazole, 0.5 parts of leveling agent sodium polyacrylate, and 0.1 parts of photoinitiator are placed in a high-speed disperser and stirred and dispersed to obtain a corrosion-resistant coating;

[0036] S4: Apply the corrosion-resistant coating to the surface of the aluminum alloy material with a coating thickness of 25 μm, irradiate with 350 nm ultraviolet light for 1 hour, heat to 100° C. and cure for 3 hours, cure at 120° C. for 2 hours, dry and cool to obtain an aluminum alloy composite material with a corrosion-resistant coating on the surface.

[0037] Example 3: S1: Take 1.5 parts of catechin aldehyde and 2 parts of 4-fluoro-1-aminonaphthalene, add them to 25 parts of anhydrous methanol, stir evenly, heat to reflux for 8 hours, remove the solvent to obtain a fluorinated Schiff base; take 2.5 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 40 parts of 1,4-dioxane, and 4 parts of a fluorinated Schiff base, heat to 70°C, stir to react for 6 hours, and remove the solvent to obtain a flame retardant;

[0038] S2: Take 0.5 parts of carboxylated carbon nanotubes, add 60 parts of thionyl chloride and 1 part of N,N-dimethylformamide under nitrogen protection, stir for 5 minutes, ultrasonically disperse at 30°C for 3 hours, reflux at 70°C for 24 hours, filter and take the solid, wash and dry to obtain chlorinated carbon nanotubes; take 2 parts of chlorinated carbon nanotubes, add them to 100 parts of tetrahydrofuran and stir evenly, add 1 part of trihydroxy heptaoctyl poss, stir at 50°C for 72 hours, filter and take the solid, wash and dry to obtain a composite filler; add 10 parts of the composite filler to 100 parts of Stirring the mixture of ethanol and water (volume ratio of ethanol to water 7:3) evenly, adding 1 part of 3-(2,3-epoxypropoxy)propyltrimethoxysilane, mixing evenly, stirring and reacting at 70°C for 8 hours, filtering and collecting the solid, and washing to obtain an epoxidized composite filler; adding 12 parts of the epoxidized composite filler to 100 parts of benzene, adding 2 parts of hydroxyl-terminated methyl vinyl silicone oil and 0.01 parts of triethanolamine, stirring and reacting at 100°C under nitrogen protection for 3 hours, adding 6 parts of hydroxyl fluorosilicone oil, continuing to stir and maintain the temperature for 3 hours, removing the solvent and catalyst to obtain a modified filler;

[0039] S3: 45 parts of epoxy resin, 10 parts of active diluent allyl glycidyl ether, 30 parts of modified filler, 6 parts of flame retardant, 8 parts of m-xylenediamine, 1 part of imidazole, 0.5 parts of leveling agent sodium polyacrylate, and 0.1 parts of photoinitiator are placed in a high-speed disperser and stirred and dispersed to obtain a corrosion-resistant coating;

[0040] S4: Apply the corrosion-resistant coating to the surface of the aluminum alloy material with a coating thickness of 25 μm, irradiate with 350 nm ultraviolet light for 1 hour, heat to 80° C. and cure for 3 hours, then cure at 130° C. for 3 hours, dry and cool to obtain an aluminum alloy composite material with a corrosion-resistant coating on the surface.

[0041] Comparative Example 1 (the addition ratio of the modified filler and the flame retardant was changed, and the remaining method steps were consistent with Example 1): S1: 1.4 parts of catechin aldehyde and 1.6 parts of 4-fluoro-1-aminonaphthalene were added to 25 parts of anhydrous methanol, stirred evenly, heated to reflux for 8 hours, and the solvent was removed to obtain a fluorinated Schiff base; 2.2 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 40 parts of 1,4-dioxane, and 3 parts of a fluorinated Schiff base were added, the temperature was raised to 70° C., stirred for reaction for 6 hours, and the solvent was removed to obtain a flame retardant;

[0042] S2: Take 0.5 parts of carboxylated carbon nanotubes, add 60 parts of thionyl chloride and 1 part of N,N-dimethylformamide under nitrogen protection, stir for 5 minutes, ultrasonically disperse at 30°C for 3 hours, reflux at 70°C for 24 hours, filter and take the solid, wash and dry to obtain chlorinated carbon nanotubes; take 2 parts of chlorinated carbon nanotubes, add them to 100 parts of tetrahydrofuran and stir evenly, add 1 part of trihydroxy heptaoctyl poss, stir at 50°C for 72 hours, filter and take the solid, wash and dry to obtain a composite filler; add 10 parts of the composite filler to 100 parts of Stirring the mixture of ethanol and water (volume ratio of ethanol to water 7:3) evenly, adding 1 part of 3-(2,3-epoxypropoxy)propyltrimethoxysilane, mixing evenly, stirring and reacting at 70°C for 8 hours, filtering and collecting the solid, and washing to obtain an epoxidized composite filler; adding 12 parts of the epoxidized composite filler to 100 parts of benzene, adding 3 parts of hydroxyl-terminated methyl vinyl silicone oil and 0.01 parts of triethanolamine, stirring and reacting at 120°C under nitrogen protection for 3 hours, adding 6 parts of hydroxyl fluorosilicone oil, continuing to stir and maintain the temperature for 3 hours, removing the solvent and catalyst to obtain a modified filler;

[0043] S3: 40 parts of epoxy resin, 10 parts of active diluent allyl glycidyl ether, 22 parts of modified filler, 10 parts of flame retardant, 8 parts of m-xylenediamine, 1 part of imidazole, 0.5 parts of leveling agent sodium polyacrylate, and 0.1 parts of photoinitiator are placed in a high-speed disperser and stirred and dispersed to obtain a corrosion-resistant coating;

[0044] S4: Apply the corrosion-resistant coating to the surface of the aluminum alloy material with a coating thickness of 25 μm, irradiate with 350 nm ultraviolet light for 1 hour, heat to 80° C. and cure for 4 hours, then cure at 130° C. for 2 hours, dry and cool to obtain an aluminum alloy composite material with a corrosion-resistant coating on the surface.

[0045] Comparative Example 2 (the addition ratio of the modified filler and the flame retardant was changed, and the remaining method steps were consistent with Example 1): S1: 1.4 parts of catechin aldehyde and 1.6 parts of 4-fluoro-1-aminonaphthalene were added to 25 parts of anhydrous methanol, stirred evenly, heated to reflux for 8 hours, and the solvent was removed to obtain a fluorinated Schiff base; 2.2 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 40 parts of 1,4-dioxane, and 3 parts of a fluorinated Schiff base were added, the temperature was raised to 70° C., stirred for reaction for 6 hours, and the solvent was removed to obtain a flame retardant;

[0046] S2: Take 0.5 parts of carboxylated carbon nanotubes, add 60 parts of thionyl chloride and 1 part of N,N-dimethylformamide under nitrogen protection, stir for 5 minutes, ultrasonically disperse at 30°C for 3 hours, reflux at 70°C for 24 hours, filter and take the solid, wash and dry to obtain chlorinated carbon nanotubes; take 2 parts of chlorinated carbon nanotubes, add them to 100 parts of tetrahydrofuran and stir evenly, add 1 part of trihydroxy heptaoctyl poss, stir at 50°C for 72 hours, filter and take the solid, wash and dry to obtain a composite filler; add 10 parts of the composite filler to 100 parts of Stirring the mixture of ethanol and water (volume ratio of ethanol to water 7:3) evenly, adding 1 part of 3-(2,3-epoxypropoxy)propyltrimethoxysilane, mixing evenly, stirring and reacting at 70°C for 8 hours, filtering and collecting the solid, and washing to obtain an epoxidized composite filler; adding 12 parts of the epoxidized composite filler to 100 parts of benzene, adding 3 parts of hydroxyl-terminated methyl vinyl silicone oil and 0.01 parts of triethanolamine, stirring and reacting at 120°C under nitrogen protection for 3 hours, adding 6 parts of hydroxyl fluorosilicone oil, continuing to stir and maintain the temperature for 3 hours, removing the solvent and catalyst to obtain a modified filler;

[0047] S3: 40 parts of epoxy resin, 10 parts of active diluent allyl glycidyl ether, 32 parts of modified filler, 4 parts of flame retardant, 8 parts of m-xylenediamine, 1 part of imidazole, 0.5 parts of leveling agent sodium polyacrylate, and 0.1 parts of photoinitiator are placed in a high-speed disperser and stirred and dispersed to obtain a corrosion-resistant coating;

[0048] S4: Apply the corrosion-resistant coating to the surface of the aluminum alloy material with a coating thickness of 25 μm, irradiate with 350 nm ultraviolet light for 1 hour, heat to 80° C. and cure for 4 hours, then cure at 130° C. for 2 hours, dry and cool to obtain an aluminum alloy composite material with a corrosion-resistant coating on the surface.

[0049] Comparative Example 3 (using 1,4-butanediol diglycidyl ether as the active diluent and no photoinitiator is added, and the remaining method steps are the same as Example 1): S1: Take 1.4 parts of catechin aldehyde and 1.6 parts of 4-fluoro-1-aminonaphthalene, add them to 25 parts of anhydrous methanol, stir evenly, heat to reflux for 8 hours, and remove the solvent to obtain a fluorine-containing Schiff base; take 2.2 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 40 parts of 1,4-dioxane, and 3 parts of a fluorine-containing Schiff base, heat to 70°C, stir to react for 6 hours, and remove the solvent to obtain a flame retardant;

[0050] S2: Take 0.5 parts of carboxylated carbon nanotubes, add 60 parts of thionyl chloride and 1 part of N,N-dimethylformamide under nitrogen protection, stir for 5 minutes, ultrasonically disperse at 30°C for 3 hours, reflux at 70°C for 24 hours, filter and take the solid, wash and dry to obtain chlorinated carbon nanotubes; take 2 parts of chlorinated carbon nanotubes, add them to 100 parts of tetrahydrofuran and stir evenly, add 1 part of trihydroxy heptaoctyl poss, stir at 50°C for 72 hours, filter and take the solid, wash and dry to obtain a composite filler; add 10 parts of the composite filler to 100 parts of Stir evenly in an ethanol-water mixed solution (ethanol to water volume ratio of 7:3), add 1 part of 3-(2,3-epoxypropoxy)propyltrimethoxysilane, mix evenly, and react at 70°C with stirring for 8 hours. Filter and wash the solid to obtain an epoxidized composite filler. Add 12 parts of the epoxidized composite filler to 100 parts of benzene, add 3 parts of hydroxyl-terminated methyl vinyl silicone oil and 0.01 parts of triethanolamine, and react at 120°C with stirring for 3 hours under nitrogen protection. Add 6 parts of hydroxyfluorosilicone oil, continue to stir at this temperature for 3 hours, and remove the solvent and catalyst to obtain a modified filler.

[0051] S3: 40 parts of epoxy resin, 10 parts of active diluent 1,4-butanediol diglycidyl ether, 28 parts of modified filler, 6 parts of flame retardant, 8 parts of m-xylylenediamine, 1 part of imidazole, and 0.5 parts of leveling agent sodium polyacrylate are placed in a high-speed disperser and stirred and dispersed to obtain a corrosion-resistant coating;

[0052] S4: Apply the corrosion-resistant coating to the surface of the aluminum alloy material with a coating thickness of 25 μm, irradiate with 350 nm ultraviolet light for 1 hour, heat to 80° C. and cure for 4 hours, then cure at 130° C. for 2 hours, dry and cool to obtain an aluminum alloy composite material with a corrosion-resistant coating on the surface.

[0053] Comparative Example 4 (the preparation method of the modified filler was changed, and the remaining steps were the same as those in Example 1): S1: 1.4 parts of catechin aldehyde and 1.6 parts of 4-fluoro-1-aminonaphthalene were added to 25 parts of anhydrous methanol, stirred evenly, heated to reflux for 8 hours, and the solvent was removed to obtain a fluorinated Schiff base; 2.2 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 40 parts of 1,4-dioxane, and 3 parts of a fluorinated Schiff base were added, the temperature was raised to 70° C., stirred for reaction for 6 hours, and the solvent was removed to obtain a flame retardant;

[0054] S2: Take 0.5 parts of carboxylated carbon nanotubes, add 60 parts of thionyl chloride and 1 part of N,N-dimethylformamide under nitrogen protection, stir for 5 minutes, ultrasonically disperse at 30°C for 3 hours, reflux at 70°C for 24 hours, filter out the solid, wash and dry to obtain chlorinated carbon nanotubes; take 2 parts of chlorinated carbon nanotubes, add them to 100 parts of tetrahydrofuran and stir evenly, add 1 part of trihydroxy heptaoctyl poss, stir at 50°C for 72 hours, filter out the solid, wash and dry to obtain a composite filler; add 10 parts of composite The composite filler was added to 100 parts of an ethanol-water mixed solution (ethanol to water volume ratio of 7:3) and stirred evenly. 1 part of 3-(2,3-epoxypropoxy)propyltrimethoxysilane was added and mixed evenly. The mixture was stirred at 120°C for 8 hours. The solid was filtered and washed to obtain an epoxidized composite filler. 12 parts of the epoxidized composite filler was added to 100 parts of benzene. 6 parts of hydroxy-terminated methyl vinyl silicone oil, 0.01 parts of triethanolamine, and 3 parts of hydroxy fluorosilicone oil were added. The mixture was stirred at this temperature for 6 hours. The solvent and catalyst were removed to obtain a modified filler.

[0055] S3: 40 parts of epoxy resin, 10 parts of active diluent allyl glycidyl ether, 28 parts of modified filler, 6 parts of flame retardant, 8 parts of m-xylenediamine, 1 part of imidazole, 0.5 parts of leveling agent sodium polyacrylate, and 0.1 parts of photoinitiator are placed in a high-speed disperser and stirred and dispersed to obtain a corrosion-resistant coating;

[0056] S4: Apply the corrosion-resistant coating to the surface of the aluminum alloy material with a coating thickness of 25 μm, irradiate with 350 nm ultraviolet light for 1 hour, heat to 80° C. and cure for 4 hours, then cure at 130° C. for 2 hours, dry and cool to obtain an aluminum alloy composite material with a corrosion-resistant coating on the surface.

[0057] Performance test: The aluminum alloy composite materials with corrosion-resistant coatings prepared in Examples 1 to 3 and Comparative Examples 1 to 4 were tested for (1) impact resistance of the coatings according to GB / T1843-2008; (2) flame retardancy was evaluated by testing the limiting oxygen index; see Table 1 for details.

[0058] Table 1:

[0059]

[0060] (3) The corrosion potentials of Examples 1 to 3 were tested, as shown in Table 2.

[0061] Table 2:

[0062]

[0063] Conclusion: The aluminum alloy composite material with a corrosion-resistant coating on the surface prepared by this scheme has excellent corrosion resistance; Comparative Example 1 and Comparative Example 2 change the addition ratio of modified filler and flame retardant, which leads to a decrease in performance, so it can be seen that the addition amount needs to be controlled; Comparative Example 3 uses 1,4-butanediol diglycidyl ether as an active diluent and does not add a photoinitiator, which leads to a decrease in performance due to changes in cross-linking degree and overall compatibility; Comparative Example 4 changes the preparation method of the modified filler and changes the addition amount of the two silicone oils, and the performance is not as good as the embodiment; In summary, the aluminum alloy composite material with a corrosion-resistant coating on the surface has excellent corrosion resistance, flame retardancy and impact resistance.

[0064] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for preparing an aluminum alloy composite material based on a corrosion-resistant coating, characterized in that: The following steps are involved: S1: Take catecholaldehyde and 4-fluoro-1-aminonaphthalene, add them to anhydrous methanol, stir evenly, heat under reflux for reaction, remove the solvent to obtain a fluorinated Schiff base; take 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 1,4-dioxane, and a fluorinated Schiff base, heat and stir for reaction, remove the solvent to obtain a flame retardant; S2: stirring and dispersing epoxy resin, reactive diluent, modified filler, flame retardant, curing agent, imidazole, leveling agent, and photoinitiator to obtain a corrosion-resistant coating; S3: applying the corrosion-resistant coating to the surface of the aluminum alloy material, solidifying, drying and cooling, and obtaining an aluminum alloy composite material having the corrosion-resistant coating on the surface.

2. The method for preparing an aluminum alloy composite material based on a corrosion-resistant coating according to claim 1, characterized in that: The fluorine-containing Schiff base includes the following raw materials, in parts by mass: 1-1.5 parts of catechin aldehyde, 1.5-2 parts of 4-fluoro-1-aminonaphthalene, and 20-30 parts of anhydrous methanol; the flame retardant includes the following raw materials, in parts by mass: 2-2.5 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 20-50 parts of 1,4-dioxane, and 2-4 parts of fluorine-containing Schiff base.

3. The method for preparing an aluminum alloy composite material based on a corrosion-resistant coating according to claim 1, characterized in that: The corrosion-resistant coating includes the following raw materials, calculated by mass: 35-45 parts of epoxy resin, 8-12 parts of active diluent, 25-30 parts of modified filler, 5-8 parts of flame retardant, 6-10 parts of curing agent, 1-2 parts of imidazole, 0.5-1 part of leveling agent, and 0.1-0.2 part of photoinitiator.

4. The method for preparing an aluminum alloy composite material based on a corrosion-resistant coating according to claim 1, characterized in that: The preparation of the modified filler comprises the following steps: Take carboxylated carbon nanotubes, add thionyl chloride and N,N-dimethylformamide under nitrogen protection, stir for 5-6 minutes, ultrasonically disperse at 20-30°C for 2-3 hours, reflux for 20-25 hours, filter and collect the solid, wash and dry to obtain acyl chloride carbon nanotubes; Add acyl chloride carbon nanotubes to tetrahydrofuran and stir evenly, add trihydroxy heptaoctyl poss, stir and react at 40-50°C for 70-75h, filter and collect the solid, wash and dry to obtain a composite filler; The composite filler is added to the ethanol-water mixed solution and stirred evenly, 3-(2,3-epoxypropoxy)propyltrimethoxysilane is added and mixed evenly, and the mixture is stirred at 60-70° C. for 4-8 hours, and the solid is filtered and washed to obtain the epoxidized composite filler; Add the epoxidized composite filler to benzene, add hydroxyl-terminated methyl vinyl silicone oil and triethanolamine, stir evenly, stir and react at 100-120°C under nitrogen protection for 2-3 hours, add hydroxyl fluorosilicone oil, keep warm and stir for 2-3 hours, remove the solvent and catalyst to obtain the modified filler.

5. The method for preparing an aluminum alloy composite material based on a corrosion-resistant coating according to claim 4, characterized in that: The acyl chloride carbon nanotubes include the following raw materials, calculated by weight: 0.3-0.5 parts of carboxylated carbon nanotubes, 50-60 parts of thionyl chloride, and 1-2 parts of N,N-dimethylformamide; The composite filler comprises the following raw materials, calculated by weight: 1-2 parts of acyl chloride carbon nanotubes and 1-2 parts of trihydroxy heptaoctyl poss.

6. The method for preparing an aluminum alloy composite material based on a corrosion-resistant coating according to claim 4, characterized in that: The epoxidized composite filler comprises the following raw materials, calculated by weight: 10 to 15 parts of composite filler, 1 to 2 parts of 3-(2,3-epoxypropoxy)propyltrimethoxysilane; The modified filler comprises the following raw materials, calculated by mass: 10-15 parts of epoxidized composite filler, 2-4 parts of hydroxyl-terminated vinyl silicone oil, 0.1-0.2 parts of triethanolamine, and 5-8 parts of hydroxyl fluorosilicone oil.

7. The method for preparing an aluminum alloy composite material based on a corrosion-resistant coating according to claim 1, characterized in that: Curing conditions are: UV light irradiation for 1~2 hours, curing at 80~100℃ for 3~4 hours, and curing at 120~130℃ for 2~3 hours.

8. The method for preparing an aluminum alloy composite material based on a corrosion-resistant coating according to claim 1, characterized in that: The active diluent is allyl glycidyl ether.

9. The method for preparing an aluminum alloy composite material based on a corrosion-resistant coating according to claim 1, characterized in that: The aluminum alloy material includes the following components: 0.1-0.3% Cu, 0.3-0.5% Mn, 0.2-0.4% Fe, 0.2-0.4% Si, 0.6-1% Mg, 0.01-0.02% Ti, 0.03-0.05% Zn, 0.05-0.25% Cr, and the balance is Al and unavoidable impurities.

10. The aluminum alloy composite material prepared according to the method for preparing an aluminum alloy composite material based on a corrosion-resistant coating according to any one of claims 1 to 9.

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