Gold-copper alloy anti-abrasion antibacterial composite coating and preparation method and application thereof

Abstract

The invention discloses a gold-copper alloy anti-abrasion antibacterial composite coating and a preparation method and application thereof.The gold-copper alloy anti-abrasion antibacterial composite coating comprises a bottom layer and an anti-abrasion antibacterial modified layer, the bottom layer comprises chromium and chromium nitride, and the anti-abrasion antibacterial modified layer comprises an anti-abrasion antibacterial modifier and polysiloxane modified acrylic resin; the wear-resistant antibacterial modifier is prepared from the following raw material components in parts by mass: 30 to 50 parts of zinc-doped mesoporous silicon dioxide nanospheres, 5 to 10 parts of hydroxyethyl methacrylate phosphate, 1 to 5 parts of nano cerium oxide, 1 to 3 parts of carboxylated graphene oxide, 1 to 5 parts of a polyacrylic acid dispersant, 3 to 5 parts of a polyether modified polysiloxane flatting agent and 2 to 6 parts of a polymer defoaming agent. 1-3 parts of a photoinitiator; the composite coating has excellent wear resistance and antibacterial property.

Description

Technical Field

[0001] This application relates to the field of gold-copper alloy surface protection technology, and in particular to a gold-copper alloy anti-wear and antibacterial composite coating, its preparation method and application. Background Technology

[0002] Due to their unique metallic properties, gold-copper alloys are an ideal material for personal decorative components. In traditional metal surface treatment techniques, gold-copper alloys are often enhanced through electroplating, heat treatment, or physical vapor deposition (PVD). Electroplating improves corrosion resistance and wear resistance by depositing metal or alloy coatings on the alloy surface; heat treatment optimizes the internal structure of the alloy by controlling the heating and cooling process, enhancing hardness and wear resistance; and physical vapor deposition utilizes physical processes in a vacuum environment to form a dense, uniform coating on the alloy surface, further strengthening wear resistance. These techniques all focus on improving the wear resistance of gold-copper alloys by altering the surface microstructure or adding protective layers, thereby extending the service life of decorative components.

[0003] Although the above technologies are effective in improving wear resistance, it is difficult to achieve a lasting antibacterial effect while ensuring wear resistance. There is a conflict between the functional requirements of antibacterial coatings and wear-resistant coatings. Antibacterial coatings need to expose active antibacterial components to perform their function, but during the wear-resistant strengthening process, the coating is easily damaged by mechanical wear or surface smoothing treatment, resulting in a decrease in antibacterial performance. On the other hand, in order to reduce surface roughness and increase hardness, wear-resistant strengthening treatment often reduces the micro-uneven structure of the surface, weakens the adhesion sites of antibacterial agents, and reduces their load and stability. Summary of the Invention

[0004] To address the technical challenge of achieving both wear resistance and antibacterial properties, a gold-copper alloy wear-resistant and antibacterial composite coating, its preparation method, and its application are provided.

[0005] The first inventive objective of this invention is achieved through the following technical solution: A gold-copper alloy anti-wear and antibacterial composite coating includes a base layer and a wear-resistant and antibacterial modified layer. The base layer includes chromium and chromium nitride. The wear-resistant and antibacterial modified layer includes a wear-resistant and antibacterial modifier and polysiloxane-modified acrylic resin. The wear-resistant and antibacterial modifier comprises the following raw material components in parts by weight: 30-50 parts of zinc-doped mesoporous silica nanospheres 5-10 parts of hydroxyethyl methacrylate phosphate 1-5 parts of nano-cerium oxide 1-3 parts of carboxylated graphene oxide 1-5 parts of polyacrylic acid dispersant 3-5 parts of polyether-modified polysiloxane leveling agent, 2-6 parts of polymer defoamer 1-3 parts of photoinitiator.

[0006] By adopting the above technical solution, the bottom layer is composed of chromium and chromium nitride, forming a dense film with strong adhesion to the metal substrate. This strengthens the substrate's resistance to plastic deformation, provides wear resistance, and effectively blocks the penetration of external corrosive media. The wear-resistant and antibacterial modified layer imparts wear resistance and antibacterial properties to the coating through wear-resistant and antibacterial modifiers and polysiloxane-modified acrylic resin. The polysiloxane-modified acrylic resin combines the curability of acrylic segments with the flexibility and low surface energy of polysiloxane segments to form a cross-linked network, giving the coating good toughness and surface smoothness, and providing a continuous phase for the dispersion of functional fillers. Zinc-doped mesoporous silica nanospheres have a high specific surface area and pore volume due to their mesoporous structure. They can load zinc ions and release antibacterial ions in a sustained manner through a slow-release mechanism. Zinc ions can interfere with bacterial metabolism. At the same time, the silica nanospheres themselves are rigid particles and, as a hard reinforcing phase, can effectively hinder the propagation of microcracks during friction and improve the wear resistance of the coating. Hydroxyethyl methacrylate phosphate is a functional monomer. The phosphate groups in its molecule can form stable phosphorus-oxygen bonds with the oxides on the underlying surface, enhancing the chemical bonding between the modified layer and the underlying layer. Meanwhile, the methacryloyl group at its end participates in the photocuring crosslinking reaction and becomes part of the resin network. Nano-cerium oxide, as a nano-hard filler, has extremely high hardness and can be uniformly dispersed in the resin matrix, filling the gaps between polymer chains and other nanoparticles, improving the density and load-bearing capacity of the coating, reducing the actual contact area and adhesive wear during friction. Furthermore, nano-cerium oxide has photocatalytic activity and can generate reactive oxygen species under visible light or ultraviolet light irradiation. These reactive oxygen species can attack the cell structure of microorganisms. Carboxylated graphene oxide, as a two-dimensional nanosheet material, can form physical barriers and entanglements in resins through its sheet structure, effectively transferring and dispersing stress and inhibiting crack propagation. The abundant carboxyl functional groups not only improve its dispersibility in resins, but also form strong interfacial interactions with resins and other fillers, synergistically enhancing the toughness, hardness, and wear resistance of the coating. Furthermore, graphene oxide itself has a physical cutting effect on microbial cell membranes and produces antibacterial synergy with zinc ions and reactive oxygen species. Polyacrylic acid dispersants adsorb onto the surface of nanoparticles through their anchoring groups, and the steric hindrance effect prevents particle agglomeration, ensuring that nano-components such as zinc-doped mesoporous silica, nano-cerium oxide, and graphene oxide are uniformly and stably dispersed in the resin, thus achieving uniform coating performance. Polyether-modified polysiloxane leveling agents reduce the surface tension of the coating, promote its leveling before curing, eliminate defects such as orange peel and pinholes, and form a smooth and flat surface. Polymer defoamers destroy the elasticity of the foam film and promote the merging and escape of bubbles, preventing the coating from being trapped by bubbles during construction and curing, and avoiding the formation of structural weaknesses. Photoinitiators absorb light energy under ultraviolet irradiation of a specific wavelength, generate free radicals or cations, and initiate a rapid polymerization and cross-linking reaction between the resin and active monomers to form a solid coating with a three-dimensional network structure. In summary, the coating exhibits excellent wear resistance through the action of each component of the wear-resistant and antibacterial modifier, resisting repeated friction and scratches. It also possesses long-lasting antibacterial properties, effectively inhibiting bacterial adhesion and proliferation. The coating has strong adhesion, a smooth surface, and good durability, making it suitable for metal surface protection.

[0007] Optionally, the nano-cerium oxide is modified with an epoxy silane coupling agent.

[0008] By adopting the above technical solution, the epoxy silane coupling agent molecule has a hydrolyzable silanoxy group at one end, which can undergo a condensation reaction with the hydroxyl groups on the surface of nano-cerium oxide to form a chemical bond. The other end is an epoxy group, which can undergo a ring-opening reaction with the carboxyl or hydroxyl groups in the polysiloxane-modified acrylic resin during the curing process. This creates a molecular bridge between the nano-cerium oxide and the resin matrix, improves the dispersion stability of nano-cerium oxide in the organic phase, reduces the tendency of nanoparticles to agglomerate, and enhances the interfacial bonding force between the filler and the matrix. This reduces stress concentration and interfacial defects, makes the load more uniformly transferred in the coating, improves the reinforcing efficiency of nano-cerium oxide, further improves the wear resistance of the coating, and ensures that the nano-cerium oxide does not easily fall off the coating during long-term use, maintaining performance stability.

[0009] Optionally, the photoinitiator is 2,4,6-trimethylbenzoyl-diphenylphosphine oxide.

[0010] By adopting the above technical solution, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide belongs to the acylphosphine oxide class. Under ultraviolet light irradiation, it undergoes homolytic cleavage to generate benzoyl and phosphonyl free radicals. These highly active free radicals can efficiently initiate the polymerization of carbon-carbon double bonds in acrylic resins and promote the cross-linking reaction of monomers such as hydroxyethyl methacrylate phosphate. Moreover, it has a wide absorption spectrum, high matching degree with commonly used ultraviolet light sources, high initiation efficiency, and deep curing ability, which helps to form a uniform and dense cross-linked network, reduce unreacted monomer residues, make the coating structure more complete, and thus improve the coating hardness, wear resistance and chemical stability.

[0011] The second objective of this invention is achieved through the following technical solution: The preparation method of the above-mentioned gold-copper alloy anti-wear and antibacterial composite coating includes the following steps: S1. Substrate pretreatment: The substrate is degreased and surface activated to obtain a pretreated substrate; S2. Preparation of the bottom layer: Chromium and chromium nitride are deposited on the substrate surface using a low-temperature PVD magnetron sputtering process to obtain the bottom layer; S3. Preparation of wear-resistant and antibacterial modified layer: Mix wear-resistant and antibacterial modifier and resin, coat it on the bottom surface, and cure to obtain wear-resistant and antibacterial modified layer.

[0012] By adopting the above technical solutions, in the S1 substrate pretreatment, oil removal removes surface contaminants, and surface activation increases the surface energy of the substrate, providing a clean and activated interface for the bottom layer deposition and enhancing the coating adhesion. In the S2 preparation of the bottom layer, a low-temperature PVD magnetron sputtering process is used. This process uses plasma to bombard the target material in a vacuum environment, causing chromium atoms and chromium nitride to be deposited on the substrate surface at the atomic scale, forming a dense and high-purity coating. The low-temperature process avoids thermal damage to the substrate, and magnetron sputtering ensures that the coating is uniform and has strong adhesion. In the S3 preparation of the wear-resistant and antibacterial modified layer, the functional filler is evenly distributed in the resin through mixing and coating. After curing, a functional surface layer is formed. The entire preparation method ensures the interfacial compatibility and structural integrity between the layers. The prepared coating has a strong interlayer bond, no peeling, and uniform coverage of the wear-resistant and antibacterial functional layer.

[0013] Optionally, in step S1, the substrate is degreased and then subjected to argon and oxygen mixed plasma treatment.

[0014] By adopting the above technical solution, oxygen plasma treatment generates highly active oxygen ions, free radicals, and ultraviolet light through the ionization of oxygen. These active substances undergo physical bombardment and chemical reaction with the substrate surface, effectively removing organic residues and introducing oxygen-containing polar functional groups such as hydroxyl and carboxyl groups into the metal surface, thereby improving surface free energy and wettability, promoting chemical bonding and physical anchoring between the underlying coating and the substrate, significantly enhancing the adhesion between the coating and the substrate, reducing interface defects, and improving the durability and peel resistance of the coating.

[0015] Optionally, the deposition sequence in step S1 is chromium followed by chromium nitride.

[0016] By adopting the above technical solution, a pure chromium layer is first deposited as a transition layer. Since chromium and the gold-copper alloy substrate are similar in crystal structure and atomic radius, they are easy to form a solid solution or diffusion layer to achieve metallurgical bonding, thereby improving the adhesion strength. Subsequently, a chromium nitride layer is deposited. The chromium transition layer can alleviate the stress caused by the difference in thermal expansion coefficient and elastic modulus between chromium nitride and the substrate, avoid coating cracking or peeling, and make the coating have a gradual transition of mechanical properties from the substrate to the surface, thereby improving the overall bonding strength and load-bearing capacity.

[0017] Optionally, the mass ratio of the wear-resistant antibacterial modifier to the polysiloxane-modified acrylic resin is (1-2):10.

[0018] By adopting the above technical solution, the wear-resistant and antibacterial modifier has a sufficiently high carrying ratio in the resin matrix to exert the wear-resistant and antibacterial effect, while ensuring that the resin can fully coat and wet all filler particles to form a continuous and dense coating film. If the wear-resistant and antibacterial modifier is too little, the functional performance will be insufficient; if it is too much, it may lead to difficulty in dispersion, increased coating brittleness, and increased surface roughness.

[0019] Optionally, the thickness of the base layer is 1-5µm, and the thickness of the wear-resistant and antibacterial modified layer is 10-15µm.

[0020] By adopting the above technical solution, the 1-5µm thick base layer is sufficient to ensure excellent adhesion and wear resistance, while the 10-15µm thick wear-resistant and antibacterial modified layer provides sufficient space for the functional filler to ensure that the surface has sufficient abrasive capacity, ion slow-release capacity and catalytic active sites, thereby ensuring the long-term wear resistance and antibacterial life of the coating.

[0021] The third objective of this invention is as follows: Application of the aforementioned gold-copper alloy anti-wear and antibacterial composite coating.

[0022] In summary, this application has at least the following beneficial effects: (1) Zinc-doped mesoporous silica nanospheres load and release zinc ions through their high specific surface area mesoporous structure, thus playing an antibacterial role. At the same time, they act as a hard reinforcing phase to hinder crack propagation and improve the wear resistance of the coating. (2) The two-dimensional sheet structure of carboxylated graphene oxide forms a physical barrier, which transmits stress and inhibits cracking; the carboxyl group promotes dispersion and interfacial interaction, and synergistically improves the coating hardness and antibacterial properties. (3) Nano-cerium oxide, as a hard nanofiller, has extremely high hardness. It is uniformly dispersed and fills the resin matrix, improving density and load-bearing capacity, and reducing friction and wear. Detailed Implementation

[0023] raw material Carboxylated graphene oxide, with a sheet diameter of 0.5-5µm and a thickness of 0.8-1.2nm, was purchased from Jiangsu Xianfeng Nanomaterials Technology Co., Ltd. Polyacrylic acid dispersant, brand name PROX® A 987, purchased from Guangzhou Oupeng Chemical Co., Ltd.; Hydroxyethyl methacrylate phosphate was purchased from Shanghai Huayong New Materials Co., Ltd. The polyether-modified polysiloxane leveling agent, brand name RianPont8407, was purchased from Sichuan Ruikaibang Chemical Materials Co., Ltd. Polymer-based defoamer, brand name BYK-1642, sourced from commercially available products; 2,4,6-Trimethylbenzoyl-diphenylphosphine oxide, purity ≥99.0 wt%, purchased from Nanjing Milan Chemical Co., Ltd. Benzophenone (99wt% purity), triethanolamine (98wt% purity), tetraethyl silicate (99.999wt% purity), 3-mercaptopropionic acid (98wt% purity), and hexadecyltrimethylammonium chloride (99wt% purity) were all purchased from Shanghai Maclean Biochemical Technology Co., Ltd. γ-glycidoxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and γ-aminopropyltriethoxysilane were all purchased from Hangzhou Jessica Chemical Co., Ltd. The nano-cerium oxide (average particle size 30nm), chromium target, zinc acetate dihydrate, anhydrous ethanol, and glacial acetic acid were all sourced from commercially available materials.

[0024] Preparation Example A1 A zinc-doped mesoporous silica nanosphere is prepared by the following method: 6.5 L of triethanolamine, 11.25 L of tetraethyl silicate, and 2.2 L of 3-mercaptopropionic acid were stirred at 100 rpm for 5 min to obtain an oil phase mixture. 3.34 L of hexadecyltrimethylammonium chloride was dissolved in 130 L of deionized water to obtain a hexadecyltrimethylammonium chloride solution. The hexadecyltrimethylammonium chloride solution was heated to 60 °C in a water bath, and the oil phase mixture was placed in a 90 °C constant temperature oil bath and allowed to stand for 25 min. The preheated hexadecyltrimethylammonium chloride solution was added to the oil phase mixture, and the mixture was stirred at 300 rpm for 10 min to obtain a mixture. The mixture was ultrasonically reacted at a frequency of 40 kHz and a power density of 50 W / L for 3 h. 250 L of anhydrous ethanol was added, and the mixture was ultrasonically reacted for 1 h to obtain a reaction solution. The reaction solution was separated at 7000 rpm to obtain a filter cake. The filter cake was washed three times with anhydrous ethanol to obtain mesoporous silica microspheres. 32 kg of zinc acetate dihydrate was added to 500 L of deionized water and stirred at 500 rpm for 15 min to obtain a zinc acetate solution. Mesoporous silica microspheres were added to the zinc acetate solution and dispersed by ultrasonication at 40 kHz for 30 min. The mixture was stirred at 300 rpm for 12 h and then separated at 7000 rpm for 6 min. The mixture was then vacuum dried at 60 °C for 24 h to obtain zinc-doped mesoporous silica nanospheres.

[0025] Preparation Example A2 A modified cerium oxide nanoparticle is prepared as follows: Mix 15g of γ-glycidoxypropyltrimethoxysilane, 1L of anhydrous ethanol and 10g of deionized water at 300rpm for 5min, add glacial acetic acid to adjust the pH to 4.5±0.1, and stir at 100rpm for 2h to obtain an aqueous solution of γ-glycidoxypropyltrimethoxysilane in ethanol. 1 kg of nano-cerium oxide was added to a reaction vessel, along with 4 L of anhydrous ethanol. The mixture was stirred at 500 rpm for 30 min and then dispersed at 8000 rpm for 20 min using a high-speed disperser. While stirring at 400 rpm, an aqueous solution of γ-glycidoxypropyltrimethoxysilane in ethanol was added dropwise to the reaction vessel at a rate of 5 mL / s. After the addition was complete, the temperature was raised to 60 °C, and the reaction was carried out at 60 °C for 6 h. Heating was then stopped, and the mixture was allowed to cool naturally to room temperature (25 °C) to obtain the reactant. The reactant was filtered to obtain a filter cake, which was washed four times with anhydrous ethanol. The filter cake was then vacuum dried at 80 °C for 24 h at a vacuum degree of -0.09 MPa to obtain modified nano-cerium oxide.

[0026] Preparation Example A3 A modified nano-cerium oxide, which differs from Preparation Example A2 in that: γ-methacryloyloxypropyltrimethoxysilane is used in place of γ-glycidoxypropyltrimethoxysilane by an equal mass; the rest is the same as Preparation Example A2.

[0027] Preparation Example A4 A modified nano-cerium oxide, which differs from preparation example A2 in that: γ-aminopropyltriethoxysilane is used in place of γ-glycidoxypropyltrimethoxysilane by an equal mass; the rest is the same as preparation example A2.

[0028] Preparation Example B1 A wear-resistant and antibacterial modifier, the preparation method of which is as follows: 4 kg of zinc-doped mesoporous silica nanospheres, 0.3 kg of modified nano-cerium oxide, 0.2 kg of carboxylated graphene oxide, and 0.3 kg of polyacrylic acid dispersant were added to 0.8 kg of hydroxyethyl methacrylate phosphate. The mixture was stirred at 1200 rpm for 30 min using a high-speed dispersant to obtain a premixed slurry. This premixed slurry was then added to a mill with a spindle speed of 2000 rpm, using 0.8 mm zirconia beads as the grinding media (75% filler) for 3 h to obtain abrasive material. This abrasive material was transferred to a mixing tank, and under light-protected conditions, 0.4 kg of polyether-modified polysiloxane leveling agent, 0.4 kg of polymeric defoamer, and 0.2 kg of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide were added at a concentration of 300... The wear-resistant and antibacterial modifier was obtained by stirring at rpm for 45 min; the zinc-doped mesoporous silica nanospheres were derived from preparation example A1, and the modified cerium nanoparticles were derived from preparation example A2.

[0029] Preparation Example B2 A wear-resistant and antibacterial modifier, which differs from Preparation Example B1 in that: no zinc-doped mesoporous silica nanospheres are added; the rest is the same as Preparation Example B1.

[0030] Preparation Example B3 A wear-resistant and antibacterial modifier, which differs from Preparation Example B1 in that: no zinc-doped mesoporous silica nanospheres are added, and 3.5 kg of mesoporous silica nanospheres and 0.5 kg of zinc acetate dihydrate are added; the rest is the same as Preparation Example B1.

[0031] Preparation Example B4 A wear-resistant and antibacterial modifier, which differs from Preparation Example B1 in that it does not contain carboxylated graphene oxide; the rest is the same as Preparation Example B1.

[0032] Preparation Example B5 A wear-resistant and antibacterial modifier, which differs from preparation example B1 in that the modified nano-cerium oxide is derived from preparation example A3; the rest is the same as preparation example B1.

[0033] Preparation Example B6 A wear-resistant and antibacterial modifier, which differs from preparation example B1 in that the modified nano-cerium oxide is derived from preparation example A4; the rest is the same as preparation example B1.

[0034] Preparation Example B7 A wear-resistant and antibacterial modifier, which differs from Preparation Example B1 in that: nano-cerium oxide of equal mass is used instead of modified nano-cerium oxide; the rest is the same as Preparation Example B1.

[0035] Preparation Example B8 A wear-resistant and antibacterial modifier, which differs from Preparation Example B1 in that: benzophenone is used in place of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide by mass; the rest is the same as Preparation Example B1.

[0036] Preparation Example B9 A wear-resistant and antibacterial modifier differs from Preparation Example B1 in that: 3 kg of zinc-doped mesoporous silica nanospheres, 0.5 kg of hydroxyethyl methacrylate phosphate, 0.1 kg of modified nano-cerium oxide, 0.1 kg of carboxylated graphene oxide, 0.1 kg of polyacrylic acid dispersant, 0.3 kg of polyether-modified polysiloxane leveling agent, 0.2 kg of polymeric defoamer, and 0.1 kg of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide; the remaining components are the same as in Preparation Example B1.

[0037] Preparation Example B10 A wear-resistant and antibacterial modifier differs from Preparation Example B1 in that: 5 kg of zinc-doped mesoporous silica nanospheres, 1 kg of hydroxyethyl methacrylate phosphate, 0.5 kg of nano-cerium oxide, 0.3 kg of carboxylated graphene oxide, 0.5 kg of polyacrylic acid dispersant, 0.5 kg of polyether-modified polysiloxane leveling agent, 0.6 kg of polymeric defoamer, and 0.3 kg of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide; the remaining components are the same as in Preparation Example B1.

[0038] Example 1 A gold-copper alloy wear-resistant and antibacterial composite coating, consisting of a base layer and a wear-resistant and antibacterial modified layer, is prepared as follows: S1. Substrate Pretreatment: After ultrasonically cleaning the substrate (gold-copper alloy plate) for 15 minutes with an alkaline metal detergent, rinse the substrate surface with deionized water to remove surface oil and dry at 80℃ for 30 minutes. Place the dried substrate in a plasma treatment machine and treat it with a mixed argon and oxygen plasma at a vacuum degree of 5×10⁻⁶. -3 Under Pa conditions, a mixture of argon and oxygen gas is introduced, with an argon flow rate of 50 sccm, an oxygen flow rate of 5 sccm, a working pressure of 0.5 Pa, a radio frequency power of 100 W, and a processing time of 5 min, to obtain a pretreated substrate.

[0039] S2. Preparation of the substrate: The pretreated substrate is placed in the vacuum chamber of the PVD magnetron sputtering equipment and evacuated to a vacuum level of 5 × 10⁻⁶. -3Pa, chromium target activated, argon gas introduced at a flow rate of 55 sccm, working pressure of 0.2 Pa, sputtering power of 3.5 kW, deposition time of 12 min, obtaining a chromium layer with a thickness of 0.3 µm; nitrogen gas introduced at a flow rate of 40 sccm, while maintaining an argon gas flow rate of 55 sccm, working pressure of 0.25 Pa, sputtering frequency of 4.5 kW, deposition time of 80 min, obtaining a 2 µm chromium nitride layer; cooled to room temperature (25 °C) to obtain the bottom layer; S3. Preparation of wear-resistant and antibacterial modified layer: 1.5 kg of wear-resistant and antibacterial modifier and 10 kg of polysiloxane modified acrylic resin are mixed at 500 rpm for 30 min. The wear-resistant and antibacterial modifier is derived from preparation example B1. It is sprayed onto the bottom layer obtained in S2, with a wet film thickness of 44 µm. It is cured at 80 °C for 20 min, then heated to 120 °C and cured for 1 h to form a 12 µm wear-resistant and antibacterial modified layer, thus obtaining a gold-copper alloy wear-resistant and antibacterial composite coating.

[0040] Comparative Example 1 A gold-copper alloy wear-resistant and antibacterial composite coating differs from Example 1 in that the wear-resistant and antibacterial modifier is derived from Preparation Example B2; the rest is the same as Example 1.

[0041] Comparative Example 2 A gold-copper alloy wear-resistant and antibacterial composite coating differs from Example 1 in that the wear-resistant and antibacterial modifier is derived from Preparation Example B3; the rest is the same as Example 1.

[0042] Comparative Example 3 A gold-copper alloy wear-resistant and antibacterial composite coating differs from Example 1 in that the wear-resistant and antibacterial modifier is derived from Preparation Example B4; the rest is the same as Example 1.

[0043] Example 2 A gold-copper alloy wear-resistant and antibacterial composite coating differs from Example 1 in that the wear-resistant and antibacterial modifier is derived from Preparation Example B5; the rest is the same as Example 1.

[0044] Example 3 A gold-copper alloy wear-resistant and antibacterial composite coating differs from Example 1 in that the wear-resistant and antibacterial modifier is derived from Preparation Example B6; the rest is the same as Example 1.

[0045] Example 4 A gold-copper alloy wear-resistant and antibacterial composite coating differs from Example 1 in that the wear-resistant and antibacterial modifier is derived from Preparation Example B7; the rest is the same as in Example 1.

[0046] Example 5 A gold-copper alloy wear-resistant and antibacterial composite coating differs from Example 1 in that the wear-resistant and antibacterial modifier is derived from Preparation Example B8; the rest is the same as Example 1.

[0047] Example 6 A gold-copper alloy anti-wear and antibacterial composite coating differs from Example 1 in that: S1, substrate pretreatment: the substrate is ultrasonically cleaned for 15 minutes using an alkaline metal detergent. The substrate is a gold-copper alloy plate. The surface of the substrate is rinsed with deionized water to remove surface oil stains. It is then dried at 80°C for 30 minutes to obtain a pretreated substrate. The rest is the same as in Example 1.

[0048] Example 7 A gold-copper alloy anti-wear and antibacterial composite coating differs from Example 1 in that: S2, preparing the underlayer: the pretreated substrate is placed in the vacuum chamber of a PVD magnetron sputtering equipment and evacuated to a vacuum degree of 5×10⁻⁶. -3 Pa, chromium target activated, argon and nitrogen introduced, nitrogen flow rate 40 sccm, argon flow rate 55 sccm, working pressure 0.25 Pa, sputtering frequency 4.5 kW, deposition time 80 min, to obtain a 2.2 µm chromium nitride layer, nitrogen introduction stopped, while maintaining argon flow rate 55 sccm, working pressure 0.2 Pa, sputtering power 3.5 kW, deposition time 12 min, to obtain a chromium layer with a thickness of 0.3 µm, cooled to room temperature (25 °C) to obtain the bottom layer; the rest is the same as in Example 1.

[0049] Example 8 A gold-copper alloy wear-resistant and antibacterial composite coating differs from Example 1 in that the wear-resistant and antibacterial modifier is 1 kg; the rest is the same as in Example 1.

[0050] Example 9 A gold-copper alloy wear-resistant and antibacterial composite coating differs from Example 1 in that the wear-resistant and antibacterial modifier is 2 kg; the rest is the same as in Example 1.

[0051] Example 10 A gold-copper alloy wear-resistant and antibacterial composite coating differs from Example 1 in that the wear-resistant and antibacterial modifier is 0.5 kg; the rest is the same as in Example 1.

[0052] Example 11 A gold-copper alloy wear-resistant and antibacterial composite coating differs from Example 1 in that the wear-resistant and antibacterial modifier is 2.5 kg; the rest is the same as in Example 1.

[0053] Example 12 A gold-copper alloy wear-resistant and antibacterial composite coating differs from Example 1 in that: in step S2, the deposition time of the chromium layer is 8 min, resulting in a 0.1 µm chromium layer; the deposition time of the chromium nitride layer is 36 min, resulting in a 0.9 µm chromium nitride layer; in step S3, the wet film thickness is 36 µm, and after curing, a 10 µm wear-resistant and antibacterial modified layer is formed; the rest is the same as in Example 1.

[0054] Example 13 A gold-copper alloy wear-resistant and antibacterial composite coating differs from Example 1 in that: in step S2, the deposition time of the chromium layer is 20 min, resulting in a 0.5 µm chromium layer; the deposition time of the chromium nitride layer is 180 min, resulting in a 4.5 µm chromium nitride layer; in step S3, the wet film thickness is 52 µm, and after curing, a 15 µm wear-resistant and antibacterial modified layer is formed; the rest is the same as in Example 1.

[0055] Example 14 A gold-copper alloy wear-resistant and antibacterial composite coating differs from Example 1 in that: in step S2, the deposition time of the chromium layer is 8 min, resulting in a 0.1 µm chromium layer; the deposition time of the chromium nitride layer is 32 min, resulting in a 0.8 µm chromium nitride layer; in step S3, the wet film thickness is 28 µm, and after curing, an 8 µm wear-resistant and antibacterial modified layer is formed; the rest is the same as in Example 1.

[0056] Example 15 A gold-copper alloy wear-resistant and antibacterial composite coating differs from Example 1 in that: in step S2, the deposition time of the chromium layer is 20 min to obtain a 0.5 µm chromium layer, and the deposition time of the chromium nitride layer is 200 min to obtain a 5 µm chromium nitride layer; in step S3, the wet film thickness is 60 µm, and after curing, a 16 µm wear-resistant and antibacterial modified layer is formed; the rest is the same as in Example 1.

[0057] Example 16 A gold-copper alloy wear-resistant and antibacterial composite coating differs from Example 1 in that the wear-resistant and antibacterial modifier is derived from Preparation Example B9; the rest is the same as Example 1.

[0058] Example 17 A gold-copper alloy wear-resistant and antibacterial composite coating differs from Example 1 in that the wear-resistant and antibacterial modifier is derived from Preparation Example B10; the rest is the same as in Example 1.

[0059] The following tests were conducted on Examples 1-17 and Comparative Examples 1-3: Abrasion resistance was tested according to GB / T 23988-2009 "Determination of Abrasion Resistance of Coatings - Rotary Rubber Grinding Wheel Method". The abrasion resistance was obtained and the test results are shown in Table 1. Antibacterial properties were tested according to GB / T 21866-2008 "Determination of Antibacterial Properties and Antibacterial Effects of Antibacterial Coatings (Films)". The sample size was 50mm × 50mm. The tested bacteria were Escherichia coli (ATCC 25922) and Staphylococcus aureus (ATCC 6538). The concentration of the bacterial suspension used for inoculation was (1.0-5.0) × 10⁻⁶. 5 The inoculum was 0.2 mL, and the culture was carried out at 37℃ and 92% relative humidity for 3 days. The antibacterial rate was then measured, and the results are shown in Table 1.

[0060] Table 1. Test results of wear resistance and antibacterial properties

[0061] Based on Table 1, the test results are analyzed as follows: Compared with Example 1 and Comparative Examples 1-2, the wear resistance of the composite coating in Example 1 is greater than that of the composite coating in Comparative Examples 1-2. The antibacterial rates of Escherichia coli and Staphylococcus aureus in the composite coating of Example 1 are also greater than those in the composite coatings of Comparative Examples 1-2. The difference between Example 1 and Comparative Examples 1-2 is that: in Example 1, the wear-resistant and antibacterial modified layer of the composite coating incorporates zinc-doped mesoporous silica nanospheres; the zinc-doped mesoporous silica nanospheres, with their high specific surface area and mesoporous structure, load and slowly release zinc ions, synergistically enhancing the antibacterial efficacy; at the same time, as a rigid reinforcing phase, they can effectively inhibit the propagation of microcracks and significantly improve the wear resistance of the coating; therefore, it is necessary for the wear-resistant and antibacterial modified layer of the composite coating to include zinc-doped mesoporous silica nanospheres.

[0062] Compared with Example 1 and Comparative Example 3, the wear resistance of the composite coating in Example 1 is greater than that of the composite coating in Comparative Example 3. The antibacterial rates of Escherichia coli and Staphylococcus aureus in the composite coating of Example 1 are also greater than those in the composite coating of Comparative Example 3. The difference between Example 1 and Comparative Example 3 is that: in Example 1, the wear-resistant and antibacterial modified layer of the composite coating incorporates carboxylated graphene oxide; its two-dimensional sheet structure forms a physical barrier and entanglement network in the resin, effectively transferring stress and inhibiting cracks; its abundant carboxyl groups not only improve dispersion, but also synergistically enhance the toughness, hardness and wear resistance of the coating through strong interfacial interactions, while the sheets themselves also have the antibacterial ability to physically cut microbial cell membranes; therefore, it is necessary for the wear-resistant and antibacterial modified layer of the composite coating to include carboxylated graphene oxide.

[0063] Comparing Examples 1 and 2-4, the wear resistance of the composite coating in Examples 1-2 is greater than that in Examples 3-4, and the antibacterial rates of Escherichia coli and Staphylococcus aureus in the composite coatings of Examples 1-2 are both greater than those in Examples 3-4. The wear resistance of the composite coating in Example 3 is greater than that in Example 4, and the antibacterial rates of Escherichia coli and Staphylococcus aureus in the composite coatings of Example 3 are both greater than those in Example 4.

[0064] The difference between Examples 1 and Examples 2-4 is that the wear-resistant and antibacterial modified cerium oxide nano-coating in Examples 1-3 was modified with a silane coupling agent, while the cerium oxide nano-coating in Examples 1-2 was modified with an epoxy-based silane coupling agent. The epoxy-based silane coupling agent, through its silanoxy and epoxy groups at both ends, forms chemical bonds between the cerium oxide nano-coating surface and the resin matrix, constructing a stable molecular bridge. This significantly improves the dispersibility and interfacial bonding of the filler, resulting in more uniform load transfer and thus synergistically enhancing the wear resistance and long-term stability of the coating. Therefore, modification of the wear-resistant and antibacterial modified cerium oxide nano-coating with an epoxy-based silane coupling agent is superior in the composite coating.

[0065] Comparing Example 1 and Example 5, the wear resistance of the composite coating in Example 1 is greater than that in Example 5. The antibacterial rates of Escherichia coli and Staphylococcus aureus in the composite coating of Example 1 are also greater than those in the composite coating of Example 5.

[0066] The difference between Example 1 and Example 5 is as follows: In Example 1, the photoinitiator for the wear-resistant and antibacterial modified layer of the composite coating is 2,4,6-trimethylbenzoyl-diphenylphosphine oxide. This type of photoinitiator homolytically cleaves under ultraviolet irradiation to generate highly active free radicals, which can efficiently initiate resin polymerization and crosslinking. Its broad absorption spectrum matches well with the ultraviolet light source, possesses deep curing capability, and helps to form a uniform and dense crosslinked network, thereby significantly improving the hardness, wear resistance, and chemical stability of the coating; therefore, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide is the preferred photoinitiator for the wear-resistant and antibacterial modified layer of the composite coating.

[0067] Comparing Examples 1 and 8-11, the wear resistance of the composite coating in Example 1 is greater than that in Examples 8-11, and the antibacterial rates of Escherichia coli and Staphylococcus aureus in the composite coating of Example 1 are both greater than those in Examples 8-11. The wear resistance of the composite coating in Examples 8-9 is greater than that in Examples 10-11, and the antibacterial rates of Escherichia coli and Staphylococcus aureus in the composite coating of Examples 8-9 are both greater than those in Examples 10-11.

[0068] The difference between Example 1 and Examples 8-11 is that in Example 1, the mass ratio of the wear-resistant antibacterial modifier to the polysiloxane-modified acrylic resin in the wear-resistant and antibacterial modified layer of the composite coating is (1-2):10. This ratio allows the wear-resistant and antibacterial modifier to fully bear the function in the resin and be completely encapsulated and wetted by the resin to form a continuous and dense coating film. Therefore, the mass ratio of the wear-resistant and antibacterial modifier to the polysiloxane-modified acrylic resin in the wear-resistant and antibacterial modified layer of the composite coating is (1-2):10, which is preferred.

[0069] Comparing Examples 1 and 12-15, the wear resistance of the composite coating in Example 1 is greater than that in Examples 12-15, and the inhibition rates of Escherichia coli and Staphylococcus aureus in the composite coating of Example 1 are both greater than those in Examples 12-15. The wear resistance of the composite coating in Examples 12-13 is greater than that in Examples 14-15, and the inhibition rates of Escherichia coli and Staphylococcus aureus in the composite coating of Example 12-13 are both greater than those in Examples 14-15.

[0070] The difference between Example 1 and Examples 12-15 is that in Example 1, the thickness of the bottom layer in the composite coating is 1-5µm, and the thickness of the wear-resistant and antibacterial modified layer is 10-15µm. This thickness range ensures the basic adhesion and wear-resistant performance of the bottom layer, provides sufficient distribution space for the filler, and ensures sufficient abrasive grain containment capacity, ion slow-release effect and catalytic activity, thus ensuring the long-term wear resistance and antibacterial performance of the coating. Therefore, a bottom layer thickness of 1-5µm and a wear-resistant and antibacterial modified layer thickness of 10-15µm in the composite coating is preferred.

[0071] Comparing Example 1 and Example 16-17, the wear resistance of the composite coating in Example 1 is greater than that of the composite coating in Example 16-17. The antibacterial rates of Escherichia coli and Staphylococcus aureus in the composite coating of Example 1 are also greater than those in the composite coating of Example 16-17.

[0072] The difference between Example 1 and Examples 16-17 is that in Example 1, the mass ratio of the wear-resistant and antibacterial modifiers—zinc-doped mesoporous silica nanospheres, hydroxyethyl methacrylate phosphate, modified nano-cerium oxide, carboxylated graphene oxide, polyacrylic acid dispersant, polyether-modified polysiloxane leveling agent, polymer defoamer, and 2,4,6-trimethylbenzoyl-diphenylphosphine oxide—is 4:0.8:0.3:0.3:0.3:0.4. Therefore, the optimal mass ratio of the wear-resistant and antibacterial modifiers in the wear-resistant and antibacterial modified layer is 4:0.8:0.3:0.3:0.3:0.4:0.4:0.2.

[0073] This specific embodiment is merely an explanation of the present invention and is not intended to limit the present invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but as long as they are within the scope of protection claimed by the present invention, they are protected by patent law.

Claims

1. A gold-copper alloy anti-wear and antibacterial composite coating, characterized in that, It includes a base layer and a wear-resistant and antibacterial modified layer, wherein the base layer includes chromium and chromium nitride. The wear-resistant and antibacterial modified layer comprises a wear-resistant and antibacterial modifier and polysiloxane-modified acrylic resin. The wear-resistant and antibacterial modifier comprises the following raw material components in parts by weight: 30-50 parts of zinc-doped mesoporous silica nanospheres 5-10 parts of hydroxyethyl methacrylate phosphate 1-5 parts of nano-cerium oxide 1-3 parts of carboxylated graphene oxide 1-5 parts of polyacrylic acid dispersant 3-5 parts of polyether-modified polysiloxane leveling agent, 2-6 parts of polymer defoamer 1-3 parts of photoinitiator.

2. The gold-copper alloy anti-wear and antibacterial composite coating according to claim 1, characterized in that, The nano-cerium oxide was modified with an epoxy silane coupling agent.

3. The gold-copper alloy anti-wear and antibacterial composite coating according to claim 1, characterized in that, The photoinitiator is 2,4,6-trimethylbenzoyl-diphenylphosphine oxide.

4. A method for preparing the gold-copper alloy anti-wear and antibacterial composite coating according to any one of claims 1-3, characterized in that, Includes the following steps: S1. Substrate pretreatment: The substrate is degreased to obtain a pretreated substrate; S2. Preparation of the bottom layer: Chromium and chromium nitride are deposited on the substrate surface using a low-temperature PVD magnetron sputtering process to obtain the bottom layer; S3. Preparation of wear-resistant and antibacterial modified layer: Mix wear-resistant and antibacterial modifier with polysiloxane-modified acrylic resin, coat it on the bottom surface, and cure to obtain wear-resistant and antibacterial modified layer.

5. The method for preparing a gold-copper alloy anti-wear and antibacterial composite coating according to claim 4, characterized in that, In step S1, the substrate is degreased and then subjected to argon and oxygen mixed plasma treatment.

6. The method for preparing a gold-copper alloy anti-wear and antibacterial composite coating according to claim 4, characterized in that, In step S1, the deposition sequence is chromium followed by chromium nitride.

7. The method for preparing a gold-copper alloy anti-wear and antibacterial composite coating according to claim 4, characterized in that, The mass ratio of the wear-resistant antibacterial modifier to the polysiloxane-modified acrylic resin is (1-2):

10.

8. The method for preparing a gold-copper alloy anti-wear and antibacterial composite coating according to claim 4, characterized in that, The thickness of the bottom layer is 1-5µm, and the thickness of the wear-resistant and antibacterial modified layer is 10-15µm.

9. The application of the gold-copper alloy anti-wear and antibacterial composite coating according to any one of claims 1-3.

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