Corrosion-resistant new energy automobile aluminum alloy die casting

Abstract

The invention discloses a corrosion-resistant new energy automobile aluminum alloy die casting, and belongs to the technical field of aluminum alloys, and the corrosion-resistant new energy automobile aluminum alloy die casting is prepared through the following steps: uniformly stirring rare earth metal salt, acrylic acid modified epoxy resin emulsion, a modified silane coupling agent and a surfactant to obtain a component A, taking an epoxy resin curing agent as a component B, mixing the component A with the component B, and performing extrusion molding to obtain the corrosion-resistant new energy automobile aluminum alloy die casting. The passivating agent is obtained after uniform stirring, the passivating agent is used for dip-coating and passivating a new energy automobile aluminum alloy die casting base material, the corrosion-resistant new energy automobile aluminum alloy die casting is obtained, and the modified silane coupling agent is obtained after hydrosilylation of vinylpyridine and triethoxysilane. The preparation conditions are mild, hexavalent or trivalent chromium harmful to the environment and human bodies is not contained, the modified silane coupling agent is used as an additive, good wear resistance can be better given to a passivation film, and the corrosion resistance effect of the new energy automobile aluminum alloy die casting is further improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of aluminum alloys, and in particular relates to a corrosion-resistant aluminum alloy die-casting for new energy vehicles. Background Art

[0002] To extend driving range, new energy vehicles place high demands on lightweighting. Aluminum alloy, with its low density, can effectively reduce vehicle weight, increasing driving range without sacrificing performance while also reducing energy consumption. Aluminum alloy die-castings offer high strength, hardness, and toughness, meeting the requirements of automotive structural components and parts such as body frames, battery trays, and motor housings. This ensures safety while improving overall vehicle performance.

[0003] The aluminum oxide film on the surface of aluminum alloy die-castings is γ-Al2O3. This film forms quickly and densely, providing a relatively stable corrosion protection. However, in humid air, the film's stability decreases, making it insufficient to meet the corrosion resistance requirements of aluminum alloy die-castings in industry and production. Currently, enhancing and preventing aluminum alloy corrosion and expanding the application range and service life of aluminum alloy die-castings are essential considerations in the production and use of aluminum alloy die-castings. Surface treatment technology can fundamentally improve their corrosion resistance. To improve the corrosion resistance of aluminum alloy die-castings, they undergo surface treatment before they are officially processed and used. Currently, the most common, widespread, and effective surface treatment technology is chemical conversion coating.

[0004] Patent application CN101967633 A discloses a treatment solution and method for preparing a yellow Ti / Zr-containing passivation film on aluminum alloy surfaces. The treatment solution's components and concentrations are: 0.5g / L to 2.0g / L of fluorotitanic acid, 0.4g / L to 2.0g / L of fluorozirconic acid, 2.0g / L to 5.0g / L of a manganese salt, and 0.5g / L to 2.0g / L of an organic acid. The pH of the treatment solution is 2.0 to 3.0. The treatment solution is free of chromium and other toxic substances. The conversion process requires no heating and lasts for 5 to 30 minutes. A yellow Ti / Zr-containing chemical conversion film can be prepared on aluminum alloy surfaces. The chemical conversion film prepared by this method exhibits excellent corrosion resistance, high substrate bonding strength, and is simple to process at room temperature. The coating does not contain hexavalent or trivalent chromium, which is harmful to the environment and human health. However, this treatment method uses highly acidic conditions, which can reduce the density of the passivation film to a certain extent, resulting in a decrease in the passivation effect on aluminum materials. Summary of the Invention

[0005] The purpose of the present invention is to provide a corrosion-resistant aluminum alloy die-casting for new energy vehicles to solve the problem of poor corrosion resistance of aluminum alloy die-castings for new energy vehicles.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A corrosion-resistant aluminum alloy die-casting for new energy vehicles, comprising the following steps:

[0008] Rare earth metal salt, acrylic acid modified epoxy resin emulsion, modified silane coupling agent and surfactant are stirred evenly to obtain component A, epoxy resin curing agent is used as component B, component A and component B are mixed, and stirred evenly to obtain a passivator, and the passivator is used to dip-coat and passivate the substrate of the new energy vehicle aluminum alloy die-casting to obtain a corrosion-resistant new energy vehicle aluminum alloy die-casting. The modified silane coupling agent is obtained by hydrosilylation of vinyl pyridine and triethoxysilane.

[0009] Furthermore, the weight ratio of the rare earth metal salt, acrylic acid modified epoxy resin emulsion, modified silane coupling agent, surfactant and epoxy resin curing agent is 10-11:300:60-70:20:90.

[0010] Furthermore, the passivation time of dip-coating passivation is 1-2 minutes, the passivation temperature is 30°C, after the passivation is completed, it is placed at room temperature for 0.5h-1h until the surface is dry, and then placed in a constant temperature drying oven for drying, the drying temperature is 80°C, and the drying time is 40-50 minutes.

[0011] Furthermore, the acrylic modified epoxy resin emulsion is obtained by homopolymerization of epoxy resin and acrylic monomer.

[0012] Furthermore, the acrylic acid modified epoxy resin emulsion is prepared by the following steps:

[0013] Add epoxy resin to solvent, heat and dissolve, then add 70% initiator, then drop a mixed monomer of α-methyl acrylic acid, styrene and butyl acrylate, add the remaining initiator, raise the temperature to 110-120℃ and keep the temperature for reaction for 4-5 hours. After the reaction is completed, cool to 50-60℃, add a mixed solution of N,N-dimethylaminoethanolamine and water, neutralize the reaction liquid, and continue to keep the temperature for 2-3 hours to obtain acrylic modified epoxy resin emulsion.

[0014] Furthermore, the mass ratio of epoxy resin to mixed monomer is 10:1; the molar ratio of α-methacrylic acid, styrene and butyl acrylate is 1:1:1; and the weight ratio of the added amount of initiator to the mixed monomer is 0.005g:1g.

[0015] Furthermore, the rare earth metal salt is one of cerium salt, lanthanum salt and lanthanum salt.

[0016] Furthermore, the modified silane coupling agent is prepared by the following steps:

[0017] Under nitrogen protection, vinyl pyridine is added to the solvent, the temperature is raised to 50°C, Custer catalyst is added and stirred for 30-60 minutes, and then triethoxysilane is added. After the addition, the temperature is raised to 70°C and stirred for 36-72 hours. After the reaction is completed, the toluene is removed by suction filtration and rotary evaporation to obtain a modified silane coupling agent.

[0018] Furthermore, the molar ratio of vinyl pyridine to triethoxysilane is 1:1-1.1, and the molar ratio of vinyl pyridine, toluene and Custer catalyst is 10 g:300 mL:0.2 mL.

[0019] Furthermore, the vinylpyridine-containing compound includes one of 2-vinylpyridine, 3-vinylpyridine, 2-methyl-6-vinylpyridine, 3-methyl-5-vinylpyridine and 4,4'-divinyl-2,2'-bipyridine.

[0020] Beneficial effects of the present invention:

[0021] In order to improve the corrosion resistance of aluminum alloy die-castings, surface treatment is performed on them. The present invention provides a corrosion-resistant new energy vehicle aluminum alloy die-casting. A passivating agent is used to treat the substrate of the new energy vehicle aluminum alloy die-casting. This method does not need to consider the shape, thickness and other conditions of the aluminum alloy die-casting. The treatment process is simple, and a layer of passivation film is attached to the surface of the obtained new energy vehicle aluminum alloy die-casting. The passivation film has good corrosion resistance and can better protect the new energy vehicle aluminum alloy die-casting. The preparation conditions of the present invention are mild, and it does not contain hexavalent or trivalent chromium that is harmful to the environment and human body. In addition, it has the advantages of using a modified silane coupling agent as an additive, which can better give the passivation film good wear resistance, further improving the corrosion resistance of the new energy vehicle aluminum alloy die-casting. DETAILED DESCRIPTION

[0022] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0023] Aluminum alloy castings are oxidized during production and transportation. An oxide film forms on the surface, causing mechanical wear and stains. Therefore, a pretreatment process is required before passivation to facilitate subsequent processing. The pretreatment process involves conventional grinding, alkaline cleaning, and pickling. Grinding is performed using sandpaper until the surface is free of marks and displays a metallic luster. After grinding, the surface is rinsed and dried. After drying, alkaline solution is used for degreasing, and then pickling is performed to remove the aluminum oxide film on the surface.

[0024] The present invention provides a corrosion-resistant aluminum alloy die-casting for new energy vehicles, comprising the following steps:

[0025] The rare earth metal salt, acrylic acid modified epoxy resin emulsion, modified silane coupling agent and surfactant are stirred evenly to obtain component A, and the epoxy resin curing agent is used as component B. Component A and component B are mixed and stirred evenly to obtain a passivator, and the passivator is used to dip-coat and passivate the new energy vehicle aluminum alloy die-casting substrate to obtain a corrosion-resistant new energy vehicle aluminum alloy die-casting. The passivation time is 1-2 minutes, the passivation temperature is 30°C, and the substrate is placed at room temperature for 0.5h-1h to reach surface dryness, then placed in a constant temperature drying oven for drying, the drying temperature is 80°C, and the drying time is 40-50 minutes.

[0026] The modified silane coupling agent is obtained by the hydrosilylation reaction of vinyl pyridine and triethoxysilane. The vinyl pyridine can introduce pyridine groups, which have potential corrosion inhibition effects. It also forms complexes with rare earth metal ions, encapsulating the rare earth ions and reducing their direct contact with the external environment. This provides a shielding and protective effect, improving the stability of the rare earth ions. When the passivation film is damaged, the rare earth ions can redeposit at the site of damage, forming new rare earth compounds that repair the passivation film and restore its corrosion resistance, fully utilizing the rare earth ions. The modified silane coupling agent also participates in intermolecular condensation between the passivation agent components, hindering the penetration of corrosive media, improving the wear resistance of the passivation film, and further enhancing corrosion resistance.

[0027] In some embodiments, the weight ratio of the rare earth metal salt, acrylic acid-modified epoxy resin emulsion, modified silane coupling agent, surfactant, and epoxy resin curing agent is 10-11:300:60-70:20:90. The rare earth ions introduced by the rare earth metal salt can adsorb on the metal surface and chemically react with other components in the passivation solution, participating in the formation of the passivation film. They can alter the growth mechanism of the passivation film, promote its uniform growth, and improve its integrity and density. The acrylic acid-modified epoxy resin emulsion acts as a film-forming substance, and the modified silane coupling agent participates in intermolecular condensation to form a macromolecular skeleton, hindering the penetration of corrosive media.

[0028] In some embodiments, the acrylic modified epoxy resin emulsion is obtained by homopolymerization of epoxy resin and acrylic monomer.

[0029] In some embodiments, the acrylic acid-modified epoxy resin emulsion is prepared by the following steps:

[0030] Epoxy resin is added to a solvent and heated until dissolved. 70% of the initiator is then added, followed by a dropwise addition of a mixed monomer of α-methacrylic acid, styrene, and butyl acrylate. The remaining initiator is then added. The temperature is raised to 110-120°C and allowed to react for 4-5 hours. After the reaction is complete, the temperature is lowered to 50-60°C, and a mixed solution of N,N-dimethylaminoethanolamine and water is added to neutralize the reaction solution. The reaction mixture is then kept warm for another 3 hours to obtain an acrylic acid-modified epoxy resin emulsion. The mass ratio of epoxy resin to mixed monomers is 10:1; the molar ratio of α-methacrylic acid, styrene, and butyl acrylate is 1:1:1; and the weight ratio of initiator to mixed monomers is 0.005g:1g.

[0031] In some embodiments, the rare earth metal salt is one of a cerium salt, a lanthanum salt, and a lanthanum salt. Cerium is relatively abundant in rare earth elements and is widely distributed in rare earth ores, making its mining and extraction relatively easy and producing a large yield, thereby reducing production costs. Therefore, cerium salts are preferred for cost reasons.

[0032] In some embodiments, the modified silane coupling agent is prepared by the following steps:

[0033] Under nitrogen protection, vinyl pyridine is added to the solvent, the temperature is raised to 50°C, Custer catalyst is added and stirred for 30-60 minutes, and then triethoxysilane is added. After the addition, the temperature is raised to 70°C and stirred for 36-72 hours. After the reaction is completed, the toluene is removed by suction filtration and rotary evaporation to obtain a modified silane coupling agent.

[0034] In some embodiments, the molar ratio of vinyl pyridine to triethoxysilane is 1:1-1.1, and the molar ratio of vinyl pyridine, toluene and Custer catalyst is 10 g:300 mL:0.2 mL.

[0035] In some embodiments, the vinylpyridine-containing compound includes one of 2-vinylpyridine, 3-vinylpyridine, 2-methyl-6-vinylpyridine, 3-methyl-5-vinylpyridine, and 4,4'-divinyl-2,2'-bipyridine.

[0036] A corrosion-resistant aluminum alloy die-casting for new energy vehicles is prepared by the above-mentioned preparation method.

[0037] The following describes the details in conjunction with specific embodiments.

[0038] Example 1

[0039] This embodiment provides a corrosion-resistant aluminum alloy die-casting for new energy vehicles, comprising the following steps:

[0040] Epoxy resin (E-06) was added to a solvent and heated to 110°C until completely dissolved. Afterward, 70% of dibenzoyl peroxide (70% refers to the total amount of dibenzoyl peroxide) was added. A mixed monomer of α-methacrylic acid, styrene, and butyl acrylate was then added dropwise. The remaining dibenzoyl peroxide was added after the addition was complete. The reaction was heated to 120°C and incubated for 5 hours. After the reaction, the temperature was lowered to 60°C. A mixed solution of N,N-dimethylaminoethanolamine and water (N,N-dimethylaminoethanolamine:water ratio of 1:10) was added to neutralize the reaction solution. The reaction mixture was incubated for another 3 hours to obtain an acrylic-modified epoxy resin emulsion. The mass ratio of epoxy resin (E-06) to the mixed monomers was 10:1; the molar ratio of α-methacrylic acid, styrene, and butyl acrylate was 1:1:1; and the weight ratio of the total added dibenzoyl peroxide to the mixed monomers was 0.005g:1g.

[0041] Under nitrogen protection, vinyl pyridine was added to toluene, the temperature was raised to 50°C, a Custer catalyst was added and stirred for 30 minutes, and then triethoxysilane was added. After the addition, the temperature was raised to 70°C and stirred for 36 hours. After the reaction, the toluene was removed by suction filtration and rotary evaporation to obtain a modified silane coupling agent. The molar ratio of vinyl pyridine to triethoxysilane was 1:1, and the ratio of vinyl pyridine to toluene to Custer catalyst was 10g:300mL:0.2mL. The vinyl pyridine was 2-vinyl pyridine.

[0042] Cerium nitrate, acrylic modified epoxy resin emulsion, modified silane coupling agent, sodium lauryl sulfate, and OP-10 (octylphenol polyoxyethylene ether) were mixed to obtain component A. Component B was prepared by mixing components A and B with 810 underwater epoxy curing agent and stirring to obtain a passivator. The passivator was then applied to the substrate of a new energy vehicle aluminum alloy die-casting to passivate the substrate. The passivation time was 1 minute at a temperature of 30°C. The substrate was then allowed to stand at room temperature for 0.5 hours until surface dry, and then dried in a constant temperature drying oven at 80°C for 40 minutes. The cerium nitrate was dissolved in ethanol.

[0043] The weight ratio of the cerium nitrate, acrylic acid modified epoxy resin emulsion, modified silane coupling agent, sodium lauryl sulfate, OP-10 and 810 underwater epoxy curing agent is 10:300:60:5:15:90.

[0044] Example 2

[0045] This embodiment provides a corrosion-resistant aluminum alloy die-casting for new energy vehicles, comprising the following steps:

[0046] Acrylic acid modified epoxy resin emulsion, same as Example 1.

[0047] The modified silane coupling agent is the same as that in Example 1.

[0048] Cerium nitrate, acrylic modified epoxy resin emulsion, modified silane coupling agent, sodium lauryl sulfate, and OP-10 were mixed to obtain component A. 810 underwater epoxy curing agent was used as component B. Components A and B were mixed and stirred to obtain a passivator. The passivator was then used to passivate the substrate of a new energy vehicle aluminum alloy die-casting by dip coating to obtain a corrosion-resistant new energy vehicle aluminum alloy die-casting. The passivation time was 1 minute at a passivation temperature of 30°C. The substrate was allowed to stand at room temperature for 0.5 hours until surface dry, then dried in a constant temperature drying oven at 80°C for 40 minutes. The cerium nitrate was dissolved in ethanol.

[0049] The weight ratio of the cerium nitrate, acrylic acid modified epoxy resin emulsion, modified silane coupling agent, sodium lauryl sulfate, OP-10 and 810 underwater epoxy curing agent is 10:300:65:5:15:90.

[0050] Example 3

[0051] This embodiment provides a corrosion-resistant aluminum alloy die-casting for new energy vehicles, comprising the following steps:

[0052] Acrylic acid modified epoxy resin emulsion, same as Example 1.

[0053] The modified silane coupling agent is the same as that in Example 1.

[0054] Cerium nitrate, acrylic modified epoxy resin emulsion, modified silane coupling agent, sodium lauryl sulfate, and OP-10 were mixed to obtain component A. 810 underwater epoxy curing agent was used as component B. Components A and B were mixed and stirred to obtain a passivator. The passivator was then used to passivate the substrate of a new energy vehicle aluminum alloy die-casting by dip coating to obtain a corrosion-resistant new energy vehicle aluminum alloy die-casting. The passivation time was 1 minute at a passivation temperature of 30°C. The substrate was allowed to stand at room temperature for 0.5 hours until surface dry, then dried in a constant temperature drying oven at 80°C for 40 minutes. The cerium nitrate was dissolved in ethanol.

[0055] The weight ratio of the cerium nitrate, acrylic acid modified epoxy resin emulsion, modified silane coupling agent, sodium lauryl sulfate, OP-10 and 810 underwater epoxy curing agent is 10:300:70:5:15:90.

[0056] Example 4

[0057] This embodiment provides a corrosion-resistant aluminum alloy die-casting for new energy vehicles, comprising the following steps:

[0058] Acrylic acid modified epoxy resin emulsion, same as Example 1.

[0059] The modified silane coupling agent is the same as that in Example 1.

[0060] Cerium nitrate, acrylic modified epoxy resin emulsion, modified silane coupling agent, sodium lauryl sulfate, and OP-10 were mixed to obtain component A. Component B was 810 underwater epoxy curing agent. Components A and B were mixed and stirred to obtain a passivator. The passivator was then applied to the substrate of a new energy vehicle aluminum alloy die-casting to passivate the substrate. The passivation time was 2 minutes at a temperature of 30°C. The substrate was allowed to stand at room temperature for 1 hour until surface dry, then dried in a constant temperature drying oven at 80°C for 50 minutes. The cerium nitrate was dissolved in ethanol.

[0061] The weight ratio of the cerium nitrate, acrylic acid modified epoxy resin emulsion, modified silane coupling agent, sodium lauryl sulfate, OP-10 and 810 underwater epoxy curing agent is 11:300:60:5:15:90.

[0062] Example 5

[0063] This embodiment provides a corrosion-resistant aluminum alloy die-casting for new energy vehicles, comprising the following steps:

[0064] Acrylic acid modified epoxy resin emulsion, same as Example 1.

[0065] The preparation process and dosage ratio of the modified silane coupling agent are the same as those in Example 1, except that the vinyl pyridine is 3-vinyl pyridine.

[0066] The preparation conditions and proportions of the passivating agent are the same as those in Example 1. The weight ratio of the cerium nitrate, acrylic acid-modified epoxy resin emulsion, modified silane coupling agent, sodium lauryl sulfate, OP-10 and 810 underwater epoxy curing agent is 10:300:60:5:15:90.

[0067] Example 6

[0068] This embodiment provides a corrosion-resistant aluminum alloy die-casting for new energy vehicles, comprising the following steps:

[0069] Acrylic acid modified epoxy resin emulsion, same as Example 1.

[0070] The modified silane coupling agent is prepared as follows: under nitrogen protection, vinyl pyridine is added to toluene, the temperature is raised to 50°C, a Custer catalyst is added, and the mixture is stirred for 60 minutes. Triethoxysilane is then added, and the temperature is raised to 70°C after addition, followed by stirring and reaction for 72 hours. After the reaction, the toluene is removed by filtration and rotary evaporation to obtain the modified silane coupling agent. The molar ratio of vinyl pyridine to triethoxysilane is 1:1.1, and the ratio of vinyl pyridine to toluene to Custer catalyst is 10g:300mL:0.2mL. The vinyl pyridine is 2-vinyl pyridine.

[0071] The preparation conditions and proportions of the passivating agent are the same as those in Example 1. The weight ratio of cerium nitrate, acrylic acid-modified epoxy resin emulsion, modified silane coupling agent, sodium lauryl sulfate, OP-10 and 810 underwater epoxy curing agent is 10:300:60:5:15:90.

[0072] Example 7

[0073] This embodiment provides a corrosion-resistant aluminum alloy die-casting for new energy vehicles, comprising the following steps:

[0074] Acrylic acid modified epoxy resin emulsion, same as Example 1.

[0075] The modified silane coupling agent is prepared as follows: under nitrogen, vinyl pyridine is added to toluene, the temperature is raised to 50°C, a Custer catalyst is added, and the mixture is stirred for 60 minutes. Triethoxysilane is then added, the temperature is raised to 70°C, and the mixture is stirred for 72 hours. After the reaction, the toluene is removed by filtration and rotary evaporation to obtain the modified silane coupling agent. The molar ratio of vinyl pyridine to triethoxysilane is 1:1.1, and the ratio of vinyl pyridine to toluene to Custer catalyst is 10 g:300 mL:0.2 mL. The vinyl pyridine is 3-vinyl pyridine.

[0076] The preparation conditions and proportions of the passivating agent are the same as those in Example 1. The weight ratio of cerium nitrate, acrylic acid-modified epoxy resin emulsion, modified silane coupling agent, sodium lauryl sulfate, OP-10 and 810 underwater epoxy curing agent is 10:300:60:5:15:90.

[0077] Example 8

[0078] This embodiment provides a corrosion-resistant aluminum alloy die-casting for new energy vehicles, comprising the following steps:

[0079] Acrylic acid modified epoxy resin emulsion, same as Example 1.

[0080] The preparation process and usage ratio of the modified silane coupling agent are the same as those in Example 1, except that the vinyl pyridine is 2-methyl-6-vinyl pyridine.

[0081] The preparation conditions and proportions of the passivating agent are the same as those in Example 1. The weight ratio of cerium nitrate, acrylic acid-modified epoxy resin emulsion, modified silane coupling agent, sodium lauryl sulfate, OP-10 and 810 underwater epoxy curing agent is 10:300:60:5:15:90.

[0082] Comparative Example 1

[0083] Compared with Example 1, this comparative example differs in that the preparation ratio of the passivating agent is different. Specifically, the weight ratio of cerium nitrate, acrylic acid modified epoxy resin emulsion, modified silane coupling agent, sodium lauryl sulfate, OP-10 and 810 underwater epoxy curing agent is 10:300:100:5:15:90; the remaining raw materials and preparation process are the same as in Example 1.

[0084] Comparative Example 2

[0085] Compared with Example 1, this comparative example differs in that the preparation ratio of the passivating agent is different, and no modified silane coupling agent is added. Specifically, the weight ratio of cerium nitrate, acrylic acid modified epoxy resin emulsion, sodium lauryl sulfate, OP-10 and 810 underwater epoxy curing agent is 10:300:5:15:90; the remaining raw materials and preparation process are the same as in Example 1.

[0086] Comparative Example 3

[0087] Compared with Example 1, this comparative example differs in that the preparation ratio of the passivating agent is different, and cerium nitrate is not added. Specifically, the weight ratio of the acrylic modified epoxy resin emulsion, modified silane coupling agent, sodium lauryl sulfate, OP-10 and 810 underwater epoxy curing agent is 300:60:5:15:90; the remaining raw materials and preparation process are the same as in Example 1.

[0088] Comparative Example 4

[0089] Compared with Example 1, this comparative example differs in that the composition of the passivating agent is different, the modified silane coupling agent is replaced by the silane coupling agent KH-570, and the specific weight ratio of cerium nitrate, acrylic modified epoxy resin emulsion, silane coupling agent KH-570, sodium lauryl sulfate, OP-10 and 810 underwater epoxy curing agent is 10:300:80:5:15:90; the remaining raw materials and preparation process are the same as in Example 1.

[0090] The samples prepared in Examples 1 to 8 and Comparative Examples 1 to 5 were tested:

[0091] Salt spray resistance test: (50±5)g / L NaCl solution, pH 6.5-7.2, temperature 35℃, 24h as one observation period, record the corrosion area.

[0092] Wear test: 30μm SiC sandpaper was used as the counter-abrasive material. The test was conducted under loads of 10, 15, and 20N, with a turntable speed of 0.5m / s and a wear time of 1 minute. The worn sample was weighed using an electronic analytical balance. Each test was repeated three times and the average value was calculated.

[0093] The test results are shown in Table 1 below:

[0094] Table 1

[0095]

[0096] Test results indicate that the corrosion-resistant aluminum alloy die-castings for new energy vehicles produced by the present invention exhibit excellent salt spray corrosion resistance, with a rust area of less than 96% after a 96-hour neutral salt spray test. Furthermore, the passivation film on the surface of the aluminum alloy die-castings for new energy vehicles exhibits excellent wear resistance and chemical stability, ensuring the surface quality of the aluminum alloy die-castings for new energy vehicles. Test results indicate that the amount of modified silane coupling agent used should not be excessive, and conventional silane coupling agents cannot fully exert the protective effect of rare earth metal ions. Excessive modified silane coupling can cause self-polymerization, resulting in poor processing performance, reduced adhesion of the passivation film, and increased flaking or blistering. It can also lead to a decrease in the local hardness of the passivation film, reduced wear resistance, and poor chemical stability. Conventional silane coupling agents are unable to form complexes with rare earth metals, resulting in poor stability of the rare earth ions. Furthermore, the rare earth metal ions and silane coupling agents form a three-dimensional structure on the surface, which effectively blocks the penetration of corrosive media. However, films formed by rare earth ions alone may contain defects and pores, reducing the protective effect.

[0097] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0098] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A corrosion-resistant aluminum alloy die-casting for new energy vehicles, characterized in that: The preparation method is prepared by the following steps: rare earth metal salt, acrylic modified epoxy resin emulsion, modified silane coupling agent and surfactant are stirred evenly to obtain component A, epoxy resin curing agent is used as component B, component A and component B are mixed, and after stirring evenly, a passivator is obtained, and the passivator is used to dip-coat and passivate the substrate of the new energy vehicle aluminum alloy die-casting to obtain a corrosion-resistant new energy vehicle aluminum alloy die-casting; the modified silane coupling agent is obtained by hydrosilylation of vinyl pyridine and triethoxysilane.

2. The corrosion-resistant aluminum alloy die casting for new energy vehicles according to claim 1, characterized in that: The weight ratio of the rare earth metal salt, acrylic acid modified epoxy resin emulsion, modified silane coupling agent, surfactant and epoxy resin curing agent is 10-11:300:60-70:20:

90.

3. The corrosion-resistant aluminum alloy die casting for new energy vehicles according to claim 1, characterized in that: The passivation time of dip coating passivation is 1-2 minutes, the passivation temperature is 30℃, after the passivation is completed, it is placed at room temperature for 0.5h-1h until the surface is dry, and then placed in a constant temperature drying oven for drying, the drying temperature is 80℃, and the drying time is 40-50 minutes.

4. The corrosion-resistant aluminum alloy die casting for new energy vehicles according to claim 1, characterized in that: The acrylic acid-modified epoxy resin emulsion is obtained by homopolymerization of epoxy resin and acrylic monomer.

5. The corrosion-resistant aluminum alloy die casting for new energy vehicles according to claim 1, characterized in that: The acrylic acid modified epoxy resin emulsion is prepared by the following steps: Add epoxy resin to solvent, heat and dissolve, then add 70% initiator, then drop a mixed monomer of α-methyl acrylic acid, styrene and butyl acrylate, add the remaining initiator, raise the temperature to 110-120℃ and keep the temperature for reaction for 4-5 hours. After the reaction is completed, cool to 50-60℃, add a mixed solution of N,N-dimethylaminoethanolamine and water, neutralize the reaction liquid, and continue to keep the temperature for 2-3 hours to obtain acrylic modified epoxy resin emulsion.

6. The corrosion-resistant aluminum alloy die-casting for new energy vehicles according to claim 5, characterized in that: The mass ratio of epoxy resin to mixed monomer is 10:1; the molar ratio of α-methacrylic acid, styrene and butyl acrylate is 1:1:1; and the weight ratio of the added amount of initiator to the mixed monomer is 0.005g:1g.

7. The corrosion-resistant aluminum alloy die casting for new energy vehicles according to claim 1, characterized in that: The rare earth metal salt is one of cerium salt, lanthanum salt and lanthanum salt.

8. The corrosion-resistant aluminum alloy die casting for new energy vehicles according to claim 1, characterized in that: The modified silane coupling agent is prepared by the following steps: Under nitrogen protection, vinyl pyridine is added to the solvent, the temperature is raised to 50°C, Custer catalyst is added and stirred for 30-60 minutes, and then triethoxysilane is added. After the addition, the temperature is raised to 70°C and stirred for 36-72 hours. After the reaction is completed, the toluene is removed by suction filtration and rotary evaporation to obtain a modified silane coupling agent.

9. The corrosion-resistant aluminum alloy die casting for new energy vehicles according to claim 8, characterized in that: The molar ratio of vinyl pyridine to triethoxysilane is 1:1-1.1, and the molar ratio of vinyl pyridine, toluene and Custer catalyst is 10g:300mL:0.2mL.

10. The corrosion-resistant aluminum alloy die casting for new energy vehicles according to claim 1, characterized in that: The vinyl pyridine-containing compound includes one of 2-vinyl pyridine, 3-vinyl pyridine, 2-methyl-6-vinyl pyridine, 3-methyl-5-vinyl pyridine and 4,4'-divinyl-2,2'-bipyridine.

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