High-strength high-toughness brass material and method for producing the same

Abstract

This invention relates to the field of brass material technology, specifically a high-strength, high-toughness brass material and its preparation method. A porous oxide film is pre-formed on the brass surface through plasma electrolytic oxidation. A double-bonded silver-loaded graphene oxide-doped oxide film is then constructed on the brass surface. A photocurable sealing coating is then prepared for sealing. In the photocurable sealing coating, double-bonded silver-loaded graphene oxide and modified MXene are introduced as fillers. MXene is first thiolated with 3-mercaptopropyltriethoxysilane, and then grafted with a double-bonded dibenzimidazole ring derivative via photo-clicking to obtain modified MXene. A vinyl-terminated polyurethane is used as a crosslinking agent, and a complex crosslinking network is constructed using a blend of o-phenylphenoxyethyl acrylate, butyl acrylate, glycidyl methacrylate, and octadecyl acrylate as acrylic monomers. A diluent and solvent are introduced to extend the service life of the brass material.

Description

Technical Field

[0001] This invention relates to the field of brass materials technology, specifically a high-strength, high-toughness brass material and its preparation method. Background Technology

[0002] Copper and copper alloys play an important role in aerospace, marine engineering, transportation, machinery and instrumentation, electronics and electrical appliances, information and communication industries due to their good machinability, electrical conductivity and thermal conductivity. The research and application of high-strength and high-toughness copper alloys are particularly important to meet the comprehensive performance requirements of modern equipment for structural materials. However, these materials still face inherent performance defects, such as insufficient wear resistance and corrosion resistance, which restrict their long-term application under harsh working conditions. Especially in corrosive environments such as high temperature, high humidity and high salt spray, the surface is prone to electrochemical corrosion, which not only destroys the integrity of the material surface, but also significantly deteriorates its thermal and electrical conductivity and mechanical properties, leading to decreased device efficiency or even premature failure.

[0003] Existing technologies typically improve the corrosion resistance of copper alloy surfaces through coatings or platings. However, most electroplated layers often suffer from inherent defects such as non-dense structures and high porosity. These micropores become channels for corrosive media to penetrate into the substrate during service, thus accelerating material failure. Traditional polymer coatings, such as epoxy resin coatings and acrylic resin coatings, provide good isolation and protection, but their interfacial bonding strength with the metal substrate is insufficient, making them prone to peeling under thermal or mechanical stress. Furthermore, most polymer coatings have insulating properties, which can reduce the conductivity of surface-strengthened brass materials, limiting their application scenarios. Summary of the Invention

[0004] The purpose of this invention is to provide a high-strength, high-toughness brass material and its preparation method, so as to solve the problems in the prior art.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0006] A method for preparing a high-strength, high-toughness brass material includes the following steps:

[0007] S1: Take a brass rod as the substrate, and perform sanding, polishing, cleaning and drying in sequence to obtain a brass substrate;

[0008] S2: The brass substrate is transferred into the electrolyte, subjected to plasma electrolytic oxidation treatment, and dried to obtain the pretreated substrate;

[0009] S3: Mix vinyl-terminated polyurethane, acrylate monomer, reactive diluent, double-bonded silver-loaded graphene oxide, modified MXene, and solvent, add photoinitiator, and ultrasonically stir to obtain a sealing coating.

[0010] S4: Apply sealing coating to the surface of the pretreated substrate and perform photocuring to obtain a high-strength and high-toughness brass material.

[0011] Furthermore, the electrolyte composition is as follows: using deionized water as a solvent, it contains 8 g / L sodium silicate nonahydrate, 1 g / L sodium hydroxide, 1 g / L disodium ethylenediaminetetraacetate, and 0.2 g / L double-bonded silver-loaded graphene oxide.

[0012] Furthermore, the working conditions for plasma electrolytic oxidation treatment are as follows: positive voltage of 520V, positive current of 1.4A, frequency of 2000Hz, negative voltage of 30V, oxidation time of 30min, positive and negative duty cycles of 20%, and temperature of 40-45℃.

[0013] Furthermore, by mass parts, the sealing coating contains 5-12 parts vinyl-terminated polyurethane, 8-19 parts acrylate monomer, 4-11 parts reactive diluent, 20-25 parts solvent, and 1-3 parts photoinitiator; the mass ratio of the sum of the masses of double-bonded silver-loaded graphene oxide and modified MXene to the mass ratio of acrylate monomer is (0.1-0.15):1; the mass ratio of double-bonded silver-loaded graphene oxide to modified MXene is 1:1.

[0014] Furthermore, the reactive diluent is one or more of butyl acrylate, dipropylene glycol diacrylate, dipropylene glycol diacrylate, and trimethylolpropane trimethacrylate; the acrylate monomer is obtained by compounding o-phenylphenoxyethyl acrylate, butyl acrylate, glycidyl methacrylate, and octadecyl acrylate in a mass ratio of 4:1:1:0.3.

[0015] Furthermore, the reactive diluent is a mixture of dipropylene glycol diacrylate and trimethylolpropane trimethacrylate in a mass ratio of 3:1.

[0016] Furthermore, the preparation of double-bonded silver-supported graphene oxide includes the following steps:

[0017] (1) Mix silver nitrate and deionized water, protect from light, add ammonia water to obtain silver ammonia solution, add graphene oxide aqueous solution, stir at 48-50℃ in the dark for 20-30 min, add glucose aqueous solution, stir for 20-30 min, wash with deionized water and anhydrous ethanol by centrifugation 3-5 times in sequence, dry to obtain silver-loaded graphene oxide.

[0018] (2) Mix silver-loaded graphene oxide and ethanol aqueous solution, ultrasonically disperse for 1-2 hours, adjust the pH value to 4-5, add ethanol aqueous solution and KH-570 mixture, heat to 55-60℃ and keep warm for 11-12 hours, centrifuge, wash and dry to obtain double-bonded silver-loaded graphene oxide.

[0019] Furthermore, the preparation of vinyl-terminated polyurethane includes the following steps:

[0020] Under a nitrogen atmosphere, isophorone diisocyanate, polypropylene glycol, and hydroxyl-terminated polydimethylsiloxane are mixed, and dibutyltin dilaurate is added and mixed. The mixture is heated to 82-85℃ and stirred for 1-2 hours, then cooled to 45-50℃, and hydroxyethyl methacrylate is added and kept at the temperature for another 2-3 hours to obtain vinyl-terminated polyurethane.

[0021] Furthermore, the preparation of modified MXene includes the following steps:

[0022] 1) Under a nitrogen atmosphere, MXene and ethanol are mixed and ultrasonically stirred for 8-12 min. Triethylamine is added, the temperature is raised to 38-42℃ and stirred for 160-200 min. A mixture of 3-mercaptopropyltriethoxysilane and an aqueous ethanol solution is added, and stirring is continued for 11-12 h. The mixture is centrifuged, washed, and freeze-dried under vacuum to obtain thiolized MXene.

[0023] 2) Under a nitrogen atmosphere, thiolized MXene and ethanol are mixed and ultrasonically stirred for 5-10 min. A double-bonded dibenzimidazole ring derivative and a photoinitiator are added. The mixture is then irradiated under 365 nm ultraviolet light for 2-3 h. After centrifugation, washing, drying, and grinding, the modified MXene is obtained.

[0024] Furthermore, the preparation of the double-bonded dibenzimidazole ring derivative includes the following steps:

[0025] A. Under a nitrogen atmosphere, lauric acid, o-phenylenediamine, and xylene are mixed, heated to 158-160℃ and held for 4-5 hours, then heated to 218-220℃ and held for 160-200 minutes, cooled, and distilled under reduced pressure to obtain the benzimidazole matrix.

[0026] B. At 58-60℃, benzimidazole matrix and sodium hydroxide are mixed, dimethyl sulfoxide is added, and the mixture is stirred for 50-70 min. Epichlorohydrin is added, and the mixture is stirred for 11-12 h. After cooling, hydroxylated bisbenzimidazole ring derivative is obtained.

[0027] C. The hydroxylated bisbenzimidazole ring derivative and acryloyl chloride were mixed, and a mixture of sodium hydroxide solution and dimethyl sulfoxide solution was added. The mixture was kept at 48-50℃ for 9-10 h to obtain the bisbenzimidazole ring derivative containing double bonds.

[0028] Compared with the prior art, the beneficial effects of the present invention are:

[0029] This invention provides a high-strength, high-toughness brass material and its preparation method. By optimizing the composition and process, a hydrophobic, wear-resistant, and corrosion-resistant high-strength, high-toughness brass material is prepared, thereby significantly extending the service life of the brass material.

[0030] In this invention, a porous oxide film is pre-formed on the surface of brass by plasma electrolytic oxidation, and then a photocurable sealing coating is prepared for sealing treatment. While maintaining the electrical conductivity and heat dissipation of brass, the mechanical strength and water resistance of brass are synergistically improved, thereby enhancing the durability of brass.

[0031] By adjusting the composition of the electrolyte and process parameters, a double-bonded silver-loaded graphene oxide doped oxide film in the form of metal oxides of Cu, Zn, and Si and amorphous silicon dioxide was constructed on the surface of brass. The KH-570-modified silver-loaded graphene oxide was uniformly dispersed in the electrolyte and participated in the film formation process. While refining and homogenizing the microporous structure of the oxide film, the pre-loaded silver nanoparticles and graphene oxide sheets provided preliminary conductivity enhancement for the oxide film. The carbon-carbon double bonds on its surface provided chemical bonding sites for subsequent coatings, thereby improving the interfacial bonding strength between the subsequent coatings and the substrate.

[0032] In photocurable sealing coatings, double-bonded silver-loaded graphene oxide and modified MXene are introduced as fillers. By modifying MXene, the uniformity of MXene dispersion in the coating is improved. Together with the double-bonded silver-loaded graphene oxide, a conductive heat dissipation network is constructed. First, MXene is thiolized with 3-mercaptopropyltriethoxysilane. Then, by photo-clicking, a double-bonded bisbenzimidazole ring derivative is grafted. The double-bonded bisbenzimidazole ring derivative uses lauric acid and o-phenylenediamine as the main raw materials. Through amide cyclization, substitution and other reactions, a green, efficient and stable corrosion inhibitor is obtained. Its benzimidazole ring structure has a strong coordination adsorption capacity for copper and zinc ions, thus providing long-term protection for brass materials.

[0033] In a photocurable sealing coating, vinyl-terminated polyurethane is prepared using hydroxyl-terminated polydimethylsiloxane as a modifier. The vinyl-terminated polyurethane is then used as a crosslinking agent, and a compound of o-phenylphenoxyethyl acrylate, butyl acrylate, glycidyl methacrylate, and octadecyl acrylate is used as an acrylic monomer. Diluent and solvent are introduced, and together with double-bonded silver-loaded graphene oxide and modified MXene, a complex crosslinking network is constructed by controlling the raw material ratio. This effectively blocks the penetration of water and corrosive media, extending the service life of brass materials. Detailed Implementation

[0034] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0035] Furthermore, the technical solutions of the various embodiments can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0036] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are only used to explain the present invention and are not intended to limit the present invention.

[0037] Example 1: A method for preparing a high-strength, high-toughness brass material, comprising the following steps:

[0038] S1: Take a brass rod as the substrate, and perform sanding, polishing, cleaning and drying in sequence to obtain a brass substrate;

[0039] S2: The brass substrate is transferred into the electrolyte, subjected to plasma electrolytic oxidation treatment, and dried to obtain the pretreated substrate;

[0040] The electrolyte is composed of: deionized water as solvent, containing 8 g / L sodium silicate nonahydrate, 1 g / L sodium hydroxide, 1 g / L disodium ethylenediaminetetraacetate and 0.2 g / L double-bonded silver-loaded graphene oxide;

[0041] The working conditions for plasma electrolytic oxidation treatment are: positive voltage of 520V, positive current of 1.4A, frequency of 2000Hz, negative voltage of 30V, oxidation time of 30min, positive and negative duty cycles of 20%, and temperature of 40℃.

[0042] The preparation of the double-bonded silver-loaded graphene oxide includes the following steps:

[0043] (1) Mix 0.5g silver nitrate and 25mL deionized water, protect from light, add 5mL of 3% ammonia water to obtain silver ammonia solution, add 250mL of graphene oxide aqueous solution, stir at 48℃ in the dark for 30min, add 250mL of 2mg / mL glucose aqueous solution, stir for 20min, wash with deionized water and anhydrous ethanol three times by centrifugation, dry to obtain silver-loaded graphene oxide;

[0044] (2) Mix 0.5g of silver-loaded graphene oxide and 300mL of 95% ethanol aqueous solution, ultrasonically disperse for 1h, adjust the pH value to 4, add 50mL of 95% ethanol aqueous solution and 1.5g of KH-570 mixture, heat to 55℃ and keep warm for 12h, centrifuge, wash and dry to obtain double-bonded silver-loaded graphene oxide;

[0045] S3: Mix vinyl-terminated polyurethane, acrylate monomer, reactive diluent, double-bonded silver-loaded graphene oxide, modified MXene, and solvent, add photoinitiator, and ultrasonically stir to obtain a sealing coating.

[0046] By mass fraction, the sealing coating contains: 5 parts vinyl-terminated polyurethane, 8 parts acrylate monomer, 4 parts reactive diluent, 20 parts solvent, and 1 part photoinitiator; the mass ratio of the sum of the masses of double-bonded silver-loaded graphene oxide and modified MXene to the mass ratio of acrylate monomer in the sealing coating is 0.1:1; the mass ratio of double-bonded silver-loaded graphene oxide to modified MXene is 1:1.

[0047] The preparation of the vinyl-terminated polyurethane includes the following steps:

[0048] Under a nitrogen atmosphere, 9g of isophorone diisocyanate, 15g of polypropylene glycol, and 1g of hydroxyl-terminated polydimethylsiloxane were mixed, and 7µL of dibutyltin dilaurate was added and mixed. The mixture was heated to 82°C and stirred for 2 hours, then cooled to 45°C, and 1g of hydroxyethyl methacrylate was added and kept at the temperature for 3 hours to obtain vinyl-terminated polyurethane.

[0049] The preparation of the modified MXene includes the following steps:

[0050] (1) Mix 0.5g MXene and 30mL ethanol, sonicate for 8min, add 3mL triethylamine, heat to 38℃ and stir for 200min, add 2mL 3-mercaptopropyltriethoxysilane and 10mL deionized water mixture, continue stirring for 11h, centrifuge, wash, and freeze dry under vacuum to obtain thiolized MXene;

[0051] (2) Under a nitrogen atmosphere, 2.1g of mercapto-MXene and 30mL of ethanol were mixed, ultrasonically stirred for 5min, heated to 70℃, 1.2g of a double-bonded dibenzimidazole ring derivative and 0.4g of photoinitiator were added, and the mixture was irradiated under 365nm ultraviolet light for 2h. After centrifugation, washing, drying and grinding, the modified MXene was obtained.

[0052] The preparation of the double-bonded dibenzimidazole ring derivative includes the following steps:

[0053] 1) Under a nitrogen atmosphere, 0.1 mol of lauric acid, 0.12 mol of o-phenylenediamine, and 100 mL of xylene were mixed, heated to 158 °C and held for 4 h, then heated to 218 °C and held for 200 min, cooled, and distilled under reduced pressure to obtain the benzimidazole matrix.

[0054] 2) At 58℃, 0.1 mol of benzimidazole matrix and 0.1 mol of sodium hydroxide were mixed, 10 mL of dimethyl sulfoxide was added, and the mixture was stirred for 50 min. Then, 0.1 mol of epichlorohydrin was added, and the mixture was stirred for 11 h. After cooling, the hydroxylated bisbenzimidazole ring derivative was obtained.

[0055] 3) Mix 0.1 mol of hydroxylated bisbenzimidazole ring derivative and 0.102 mol of acryloyl chloride, add a mixture of 6 mL sodium hydroxide solution and 12 mL dimethyl sulfoxide solution, and keep warm at 48 °C for 10 h to obtain a bisbenzimidazole ring derivative containing double bonds.

[0056] S4: Apply sealing coating to the surface of the pretreated substrate and perform photocuring to obtain a high-strength and high-toughness brass material.

[0057] Example 2: A method for preparing a high-strength, high-toughness brass material, comprising the following steps:

[0058] S1: Take a brass rod as the substrate, and perform sanding, polishing, cleaning and drying in sequence to obtain a brass substrate;

[0059] S2: The brass substrate is transferred into the electrolyte, subjected to plasma electrolytic oxidation treatment, and dried to obtain the pretreated substrate;

[0060] The electrolyte is composed of: deionized water as solvent, containing 8 g / L sodium silicate nonahydrate, 1 g / L sodium hydroxide, 1 g / L disodium ethylenediaminetetraacetate and 0.2 g / L double-bonded silver-loaded graphene oxide;

[0061] The working conditions for plasma electrolytic oxidation treatment are: positive voltage of 520V, positive current of 1.4A, frequency of 2000Hz, negative voltage of 30V, oxidation time of 30min, positive and negative duty cycles of 20%, and temperature of 42℃.

[0062] The preparation of the double-bonded silver-loaded graphene oxide includes the following steps:

[0063] (1) Mix 0.5g silver nitrate and 25mL deionized water, protect from light, add 5mL of 3% ammonia water to obtain silver ammonia solution, add 250mL of graphene oxide aqueous solution, stir at 49℃ in the dark for 25min, add 250mL of 2mg / mL glucose aqueous solution, stir for 25min, wash with deionized water and anhydrous ethanol by centrifugation 4 times, dry to obtain silver-loaded graphene oxide;

[0064] (2) Mix 0.5g of silver-loaded graphene oxide and 300mL of 95% ethanol aqueous solution, ultrasonically disperse for 1.5h, adjust the pH to 4.5, add 50mL of 95% ethanol aqueous solution and 1.5g of KH-570 mixture, heat to 58℃ and keep warm for 11.5h, centrifuge, wash and dry to obtain double-bonded silver-loaded graphene oxide;

[0065] S3: Mix vinyl-terminated polyurethane, acrylate monomer, reactive diluent, double-bonded silver-loaded graphene oxide, modified MXene, and solvent, add photoinitiator, and ultrasonically stir to obtain a sealing coating.

[0066] By mass fraction, the sealing coating contains: 8 parts vinyl-terminated polyurethane, 13 parts acrylate monomer, 8 parts reactive diluent, 22 parts solvent, and 2 parts photoinitiator; the mass ratio of the sum of the masses of double-bonded silver-loaded graphene oxide and modified MXene to the mass ratio of acrylate monomer in the sealing coating is 0.11:1; the mass ratio of double-bonded silver-loaded graphene oxide to modified MXene is 1:1.

[0067] The preparation of the vinyl-terminated polyurethane includes the following steps:

[0068] Under a nitrogen atmosphere, 9g of isophorone diisocyanate, 15g of polypropylene glycol, and 1g of hydroxyl-terminated polydimethylsiloxane were mixed, and 7µL of dibutyltin dilaurate was added. The mixture was heated to 83°C and stirred for 1.5h, then cooled to 48°C, and 1g of hydroxyethyl methacrylate was added. The mixture was then kept at this temperature for another 2.5h to obtain vinyl-terminated polyurethane.

[0069] The preparation of the modified MXene includes the following steps:

[0070] (1) Mix 0.5g MXene and 30mL ethanol, sonicate for 10min, add 3mL triethylamine, heat to 40℃ and stir for 180min, add 2mL 3-mercaptopropyltriethoxysilane and 10mL deionized water mixture, continue stirring for 11.5h, centrifuge, wash, and freeze dry under vacuum to obtain thiolized MXene;

[0071] (2) Under a nitrogen atmosphere, 2.1g of mercapto-MXene and 30mL of ethanol were mixed, ultrasonically stirred for 8min, heated to 75℃, 1.2g of a double-bonded dibenzimidazole ring derivative and 0.4g of photoinitiator were added, and the mixture was irradiated under 365nm ultraviolet light for 2.5h. After centrifugation, washing, drying and grinding, the modified MXene was obtained.

[0072] The preparation of the double-bonded dibenzimidazole ring derivative includes the following steps:

[0073] 1) Under a nitrogen atmosphere, 0.1 mol of lauric acid, 0.12 mol of o-phenylenediamine, and 100 mL of xylene were mixed, heated to 159 °C and held for 3.5 h, then heated to 219 °C and held for 180 min, cooled, and distilled under reduced pressure to obtain the benzimidazole matrix.

[0074] 2) At 59℃, 0.1 mol of benzimidazole matrix and 0.1 mol of sodium hydroxide were mixed, 10 mL of dimethyl sulfoxide was added, and the mixture was stirred for 60 min. Then, 0.1 mol of epichlorohydrin was added, and the mixture was stirred for 11.5 h. After cooling, the hydroxylated bisbenzimidazole ring derivative was obtained.

[0075] 3) Mix 0.1 mol of hydroxylated bisbenzimidazole ring derivative and 0.102 mol of acryloyl chloride, add a mixture of 6 mL sodium hydroxide solution and 12 mL dimethyl sulfoxide solution, and keep warm at 49 °C for 9.5 h to obtain a bisbenzimidazole ring derivative containing double bonds.

[0076] S4: Apply sealing coating to the surface of the pretreated substrate and perform photocuring to obtain a high-strength and high-toughness brass material.

[0077] Example 3: A method for preparing a high-strength, high-toughness brass material, comprising the following steps:

[0078] S1: Take a brass rod as the substrate, and perform sanding, polishing, cleaning and drying in sequence to obtain a brass substrate;

[0079] S2: The brass substrate is transferred into the electrolyte, subjected to plasma electrolytic oxidation treatment, and dried to obtain the pretreated substrate;

[0080] The electrolyte is composed of: deionized water as solvent, containing 8 g / L sodium silicate nonahydrate, 1 g / L sodium hydroxide, 1 g / L disodium ethylenediaminetetraacetate and 0.2 g / L double-bonded silver-loaded graphene oxide;

[0081] The working conditions for plasma electrolytic oxidation treatment are: positive voltage of 520V, positive current of 1.4A, frequency of 2000Hz, negative voltage of 30V, oxidation time of 30min, positive and negative duty cycles of 20%, and temperature of 45℃.

[0082] The preparation of the double-bonded silver-loaded graphene oxide includes the following steps:

[0083] (1) Mix 0.5g silver nitrate and 25mL deionized water, protect from light, add 5mL of 3% ammonia water to obtain silver ammonia solution, add 250mL of graphene oxide aqueous solution, stir at 50℃ in the dark for 20min, add 250mL of 2mg / mL glucose aqueous solution, stir for 30min, wash with deionized water and anhydrous ethanol five times by centrifugation, and dry to obtain silver-loaded graphene oxide;

[0084] (2) Mix 0.5g of silver-loaded graphene oxide and 300mL of 95% ethanol aqueous solution, ultrasonically disperse for 2h, adjust the pH value to 5, add 50mL of 95% ethanol aqueous solution and 1.5g of KH-570 mixture, heat to 60℃ and keep warm for 11h, centrifuge, wash and dry to obtain double-bonded silver-loaded graphene oxide;

[0085] S3: Mix vinyl-terminated polyurethane, acrylate monomer, reactive diluent, double-bonded silver-loaded graphene oxide, modified MXene, and solvent, add photoinitiator, and ultrasonically stir to obtain a sealing coating.

[0086] By mass fraction, the sealing coating contains: 12 parts vinyl-terminated polyurethane, 19 parts acrylate monomer, 11 parts reactive diluent, 25 parts solvent, and 3 parts photoinitiator; the mass ratio of the sum of the masses of double-bonded silver-loaded graphene oxide and modified MXene to the mass ratio of acrylate monomer in the sealing coating is 0.15:1; the mass ratio of double-bonded silver-loaded graphene oxide to modified MXene is 1:1.

[0087] The preparation of the vinyl-terminated polyurethane includes the following steps:

[0088] Under a nitrogen atmosphere, 9g of isophorone diisocyanate, 15g of polypropylene glycol, and 1g of hydroxyl-terminated polydimethylsiloxane were mixed, and 7µL of dibutyltin dilaurate was added and mixed. The mixture was heated to 85°C and stirred for 1 hour, then cooled to 50°C, and 1g of hydroxyethyl methacrylate was added and kept at the temperature for another 3 hours to obtain vinyl-terminated polyurethane.

[0089] The preparation of the modified MXene includes the following steps:

[0090] (1) Mix 0.5g MXene and 30mL ethanol, sonicate for 12min, add 3mL triethylamine, heat to 42℃ and stir for 160min, add 2mL 3-mercaptopropyltriethoxysilane and 10mL deionized water mixture, continue stirring for 12h, centrifuge, wash, and freeze dry under vacuum to obtain thiolized MXene.

[0091] (2) Under a nitrogen atmosphere, 2.1g of mercapto-modified MXene and 30mL of ethanol were mixed, ultrasonically stirred for 10min, heated to 70℃, 1.2g of a double-bonded dibenzimidazole ring derivative and 0.4g of photoinitiator were added, and the mixture was irradiated under 365nm ultraviolet light for 3h. After centrifugation, washing, drying and grinding, modified MXene was obtained.

[0092] The preparation of the double-bonded dibenzimidazole ring derivative includes the following steps:

[0093] 1) Under a nitrogen atmosphere, 0.1 mol of lauric acid, 0.12 mol of o-phenylenediamine, and 100 mL of xylene were mixed, heated to 160 °C and held for 3 h, then heated to 220 °C and held for 160 min, cooled, and distilled under reduced pressure to obtain the benzimidazole matrix.

[0094] 2) At 60℃, 0.1 mol of benzimidazole matrix and 0.1 mol of sodium hydroxide were mixed, 10 mL of dimethyl sulfoxide was added, and the mixture was stirred for 70 min. Then, 0.1 mol of epichlorohydrin was added, and the mixture was stirred for 12 h. After cooling, the hydroxylated bisbenzimidazole ring derivative was obtained.

[0095] 3) Mix 0.1 mol of hydroxylated bisbenzimidazole ring derivative and 0.102 mol of acryloyl chloride, add a mixture of 6 mL sodium hydroxide solution and 12 mL dimethyl sulfoxide solution, and keep warm at 50 °C for 9 h to obtain a bisbenzimidazole ring derivative containing double bonds.

[0096] S4: Apply sealing coating to the surface of the pretreated substrate and perform photocuring to obtain a high-strength and high-toughness brass material.

[0097] Comparative Example 1: Example 3 was used as the control group. MXene was replaced with modified MXene, and other processes were normal.

[0098] Comparative Example 2: Using Example 3 as the control group, double-bonded silver-loaded graphene oxide was replaced with graphene oxide, while other processes were normal.

[0099] Comparative Example 3: Using Example 3 as the control group, the mass ratio of the sum of the masses of double-bonded silver-loaded graphene oxide and modified MXene to the mass ratio of acrylate monomer was 0.08, and other processes were normal.

[0100] In the examples and comparative examples:

[0101] Working conditions for photocuring: 365nm wavelength light irradiation for 30s; the thickness of the sealed coating after curing is 5µm.

[0102] The acrylate monomers are o-phenylphenoxyethyl acrylate, butyl acrylate, glycidyl methacrylate, and octadecyl acrylate in a mass ratio of 4:1:1:0.3; the reactive diluents are dipropylene glycol diacrylate and trimethylolpropane trimethacrylate in a mass ratio of 3:1.

[0103] The preparation of an aqueous solution of graphene oxide includes the following steps:

[0104] In an ice-water bath, 25 mL of concentrated sulfuric acid and 1 g of graphite powder were mixed, and 5 g of potassium permanganate was added. The mixture was stirred for 1-2 hours, then transferred to a 40°C oil bath and kept warm for 30 minutes. 45 mL of deionized water was added, and the temperature was raised to 90°C and kept warm for 1 hour. 30 mL of deionized water was added, and 30% hydrogen peroxide was added until no gas was produced. The mixture was centrifuged, and washed with 10% hydrochloric acid until no white precipitate was formed when tested with barium chloride and silver nitrate. The mixture was washed with deionized water until neutral, and then freeze-dried to obtain graphene oxide. 0.5 g of graphene oxide and 250 mL of deionized water were mixed, ultrasonically stirred for 60 minutes, and then broken up and exfoliated using an ultrasonic cell disruptor for 60 minutes to obtain an aqueous solution of graphene oxide.

[0105] The preparation of MXene includes the following steps:

[0106] 3g of titanium aluminum carbide powder was mixed with 70mL of 49% hydrofluoric acid, kept at 70℃ for 24h, cooled, washed, centrifuged until pH 7, and freeze-dried to obtain pretreated titanium aluminum carbide; 1g of pretreated titanium aluminum carbide was mixed with 17mL of DMSO, sonicated for 10min, stirred at 70℃ for 18h, centrifuged, washed, and freeze-dried to obtain MXene.

[0107] Sources of raw materials used (for illustrative purposes only):

[0108] Brass rod (H62 brass rod, Ф58, tensile strength of 380MPa at 23.5℃), graphite powder (average particle size 1µm, 99.9%), KH-570 (3-(methacryloyloxy)propyltrimethoxysilane, 2530-85-0, 99%), titanium aluminum carbide powder (200 mesh, 99%), photoinitiator (2959, 99%): commercially available; polypropylene glycol P103210, hydroxyl-terminated polydimethylsiloxane C303004, isophorone diisocyanate I109582: Aladdin reagent.

[0109] Performance testing: The brass materials prepared in the examples and comparative examples were tested.

[0110] Elongation after fracture: Tested according to GB / T228.1-2021, at a test temperature of 23.5%;

[0111] Hydrophobicity: Characterized by water contact angle testing using a contact angle tester; Adhesion: Tested according to GB / T9286-2021, temperature 25℃, relative humidity 50%, rating characterization: Grade 0 - cutting gap 3mm, with completely smooth cutting edges and no peeling; Grade 1: slight peeling at the cut, but the affected cross-cutting area is no more than 5%; Grade 2: peeling at the cut and the affected cross-cutting area is greater than 5% but not more than 15%; Abrasion resistance: Used a multi-functional surface testing machine, with 6mm GCr bearing steel balls, load 20N, reciprocating speed 100mm / min, time 30min, and characterized by volumetric wear rate; Corrosion resistance: Refer to GB / T10125-2021 neutral salt spray test, test temperature 35℃, using a 3% sodium chloride aqueous solution, after 1800h, observe whether blistering, damage, rust, etc. appear on the sample surface, no phenomenon is qualified; The results are shown in Table 1.

[0112] Table 1

[0113]

[0114] This invention provides a high-strength, high-toughness brass material and its preparation method. By optimizing the composition and process, a brass material with good conductivity, high strength, high toughness, and corrosion resistance is prepared, thereby significantly extending the service life of the brass material.

[0115] Comparing Example 3 with Comparative Example 1, it can be seen that by modifying MXene, the uniformity of MXene dispersion in the coating is improved, and a conductive network is constructed together with double-bonded silver-loaded graphene oxide. First, MXene is thiolized with 3-mercaptopropyltriethoxysilane, and then a double-bonded bisbenzimidazole ring derivative is grafted by photoclick. The double-bonded bisbenzimidazole ring derivative uses lauric acid and o-phenylenediamine as the main raw materials. Through amide cyclization, substitution and other reactions, a green, efficient, stable corrosion inhibitor that can provide long-term protection for brass materials in extreme environments is obtained. Its benzimidazole ring structure has a strong coordination adsorption capacity for copper / zinc ions, thereby providing long-term protection for brass materials.

[0116] Comparing Example 3 with Comparative Example 2, it can be seen that by adjusting the composition of the electrolyte and the process parameters, an oxide film layer consisting of silver-loaded graphene oxide doped with metal oxides of Cu, Zn, and Si elements and amorphous silicon dioxide can be constructed on the surface of brass. The silver-loaded graphene oxide modified with silane coupling agent is uniformly dispersed in the electrolyte and participates in the film formation process. While refining and homogenizing the microporous structure of the oxide film layer and improving its density, the pre-loaded silver nanoparticles and graphene oxide sheets provide preliminary conductivity enhancement for the oxide film layer. The carbon-carbon double bonds on its surface provide chemical bonding sites for subsequent coatings, thereby improving the interfacial bonding strength between the subsequent coating and the substrate.

[0117] Comparing Example 3 with Comparative Example 3, it can be seen that in the photocurable sealing coating, vinyl-terminated polyurethane is used as a crosslinking agent, dibutyltin dilaurate is used as an initiator, and isophorone diisocyanate, hydroxyl-terminated polydimethylsiloxane, polypropylene glycol and hydroxyethyl methacrylate are used as raw materials to prepare vinyl-terminated polyurethane. o-Phenylphenoxyethyl acrylate, butyl acrylate, glycidyl methacrylate and octadecyl acrylate are used as acrylic monomers, and diluents and solvents are introduced. Together with double-bonded silver-loaded graphene oxide and modified MXene conductive filler, a complex crosslinking network is constructed under photoinitiation, effectively blocking the penetration of water and corrosive media, effectively improving the corrosion resistance and hydrophobicity of the coating, achieving a balance between protection and conductivity, and effectively extending the service life of brass materials.

[0118] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the present invention's specification under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for preparing a high-strength, high-toughness brass material, characterized in that, Includes the following steps: S1: Take a brass rod as the substrate, and perform sanding, polishing, cleaning and drying in sequence to obtain a brass substrate; S2: The brass substrate is transferred into the electrolyte, subjected to plasma electrolytic oxidation treatment, and dried to obtain the pretreated substrate; S3: Mix vinyl-terminated polyurethane, acrylate monomer, reactive diluent, double-bonded silver-loaded graphene oxide, modified MXene, and solvent, add photoinitiator, and ultrasonically stir to obtain a sealing coating. S4: Apply sealing coating to the surface of pretreated substrate and perform photocuring to obtain a high-strength and high-toughness brass material; The mass ratio of the sum of the masses of double-bonded silver-loaded graphene oxide and modified MXene to the mass ratio of acrylate monomers was (0.1-0.15):1; The preparation of the double-bonded silver-loaded graphene oxide includes the following steps: (1) Mix silver nitrate and deionized water, protect from light, add ammonia water to obtain silver ammonia solution, add graphene oxide aqueous solution, stir at 48-50℃ in the dark for 20-30 min, add glucose aqueous solution, stir for 20-30 min, centrifuge, wash, and dry to obtain silver-loaded graphene oxide. (2) Mix silver-loaded graphene oxide and ethanol aqueous solution, ultrasonically disperse for 1-2 hours, adjust the pH value to 4-5, add ethanol aqueous solution and KH-570 mixture, heat to 55-60℃ and keep warm for 11-12 hours, centrifuge, wash and dry to obtain double-bonded silver-loaded graphene oxide. The preparation of the modified MXene includes the following steps: 1) Mix MXene and ethanol, sonicate and stir, add triethylamine, heat to 38-42℃ and stir for 160-200 min, add a mixture of 3-mercaptopropyltriethoxysilane and deionized water, continue stirring for 11-12 h, centrifuge, wash, and freeze dry under vacuum to obtain thiolized MXene; 2) Under a nitrogen atmosphere, thiolized MXene and ethanol were mixed and ultrasonically stirred. A double-bonded dibenzimidazole ring derivative and a photoinitiator were added. The mixture was irradiated with 365nm light for 2-3 hours, centrifuged, washed, dried and ground to obtain modified MXene.

2. The method for preparing a high-strength, high-toughness brass material according to claim 1, characterized in that, The electrolyte is composed of deionized water as solvent and contains 8 g / L sodium silicate nonahydrate, 1 g / L sodium hydroxide, 1 g / L disodium ethylenediaminetetraacetate and 0.2 g / L double-bonded silver-loaded graphene oxide.

3. The method for preparing a high-strength, high-toughness brass material according to claim 1, characterized in that, The working conditions for plasma electrolytic oxidation treatment are as follows: positive voltage 520V, positive current 1.4A, frequency 2000Hz, negative voltage 30V, oxidation time 30min, positive and negative duty cycles of 20%, and temperature 40-45℃.

4. The method for preparing a high-strength, high-toughness brass material according to claim 1, characterized in that, By mass, the sealing coating contains 5-12 parts vinyl-terminated polyurethane, 8-19 parts acrylate monomer, 4-11 parts reactive diluent, 20-25 parts solvent, and 1-3 parts photoinitiator; the mass ratio of double-bonded silver-loaded graphene oxide to modified MXene is 1:

1.

5. The method for preparing a high-strength, high-toughness brass material according to claim 1, characterized in that, The reactive diluent is one or more of butyl acrylate, dipropylene glycol diacrylate, dipropylene glycol diacrylate, and trimethylolpropane trimethacrylate; the acrylate monomer is obtained by compounding o-phenylphenoxyethyl acrylate, butyl acrylate, glycidyl methacrylate, and octadecyl acrylate in a mass ratio of 4:1:1:0.

3.

6. The method for preparing a high-strength, high-toughness brass material according to claim 1, characterized in that, The preparation of the vinyl-terminated polyurethane includes the following steps: Under a nitrogen atmosphere, isophorone diisocyanate, polypropylene glycol, and hydroxyl-terminated polydimethylsiloxane are mixed, and dibutyltin dilaurate is added and mixed. The mixture is heated to 82-85℃ and stirred for 1-2 hours, then cooled to 45-50℃, and hydroxyethyl methacrylate is added and kept at the temperature for another 2-3 hours to obtain vinyl-terminated polyurethane.

7. The method for preparing a high-strength, high-toughness brass material according to claim 1, characterized in that, The preparation of modified MXene, specifically the preparation of the double-bonded dibenzimidazole ring derivative, includes the following steps: A. Under a nitrogen atmosphere, lauric acid, o-phenylenediamine, and xylene are mixed, heated to 158-160℃ and held for 4-5 hours, then heated to 218-220℃ and held for 160-200 minutes, cooled, and distilled under reduced pressure to obtain the benzimidazole matrix. B. Mix benzimidazole matrix and sodium hydroxide, add dimethyl sulfoxide, stir at 58-60℃ for 50-70 min, add epichlorohydrin, stir for 11-12 h, cool, and obtain hydroxylated bisbenzimidazole ring derivative. C. The hydroxylated bisbenzimidazole ring derivative and acryloyl chloride were mixed and added to a mixture of sodium hydroxide solution and dimethyl sulfoxide solution. The mixture was kept at 48-50℃ for 9-10 hours to obtain the bisbenzimidazole ring derivative containing double bonds.

8. A high-strength, high-toughness brass material, characterized in that, It is prepared by the preparation method described in any one of claims 1-7.

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