A wear-resistant, corrosion-resistant, anti-fouling, and antibacterial composite modified layer for metal surfaces and its preparation method.

Abstract

This invention relates to the field of composite modification technology for metal surfaces, specifically disclosing a wear-resistant, corrosion-resistant, antifouling, and antibacterial composite modified layer for metal surfaces and its preparation method. The composite modified layer of this invention includes a microtextured layer, on which a nitrided layer is disposed. A lubricant and antibacterial silica spheres are coupled within the microtextured layer. The surface of the antibacterial silica spheres is covered with a layer of hydrophobic organic molecules; antibacterial particles are loaded within the pores of the antibacterial silica spheres. The prepared composite modified layer simultaneously possesses wear resistance and antibacterial / anti-bioadhesion properties, thus having a wider range of applications. The preparation method mainly includes the following steps: S1 Preparation of alkylated silver-loaded mesoporous silica spheres; S2 Design of the metal surface microtexture; S3 Preparation of the metal surface nitrided layer; S4 Construction of the metal surface nano-antibacterial lubricant / microtexture / nitrided coupling layer; finally, the antibacterial silica spheres are assembled inside the microtexture to prepare a composite modified layer with better wear resistance and outstanding antibacterial and anti-adhesion properties.

Description

Technical Field

[0001] This invention relates to the field of composite modification technology for metal surfaces, specifically to a wear-resistant, corrosion-resistant, anti-fouling, and antibacterial composite modification layer for metal surfaces and its preparation method. Background Technology

[0002] The statements in this section provide only background information relevant to the disclosure of this application and may not constitute prior art.

[0003] With the rapid development of industrial civilization, metallic materials are widely used in military and civilian fields due to their unique physicochemical properties. However, due to the complex and diverse operating environments, metallic materials are prone to friction, wear, fouling, and corrosion during service, leading to damage to their surface structure and, in severe cases, threatening their application reliability. Therefore, developing anti-fouling and wear-resistant modified layers will greatly improve the reliability of metallic applications.

[0004] Currently, commonly used methods in the field of metal surface protection and modification include metal surface coating treatment, metal surface alloying treatment, and metal surface structure design.

[0005] Metal surface coating treatment involves applying hydrophobic or other water-blocking organic materials to the metal surface. This technology is convenient and quick, rapidly forming a protective layer on the metal surface to prevent damage from the external environment. However, because organic materials generally have strong reactivity, the coating is prone to aging during use and easily detaches from the metal surface during complex wear processes, ultimately leading to protective failure. Furthermore, for some reactive metals, some gases and small monomers produced during the aging of organic materials can easily react with the substrate, accelerating damage and potentially causing the metal substrate to fail.

[0006] Metal surface alloying refers to the process of cladding or depositing an alloying element layer on a metal surface using techniques such as laser surface alloying, pulsed laser deposition, and magnetron sputtering to achieve a protective effect. The alloyed coating formed by this technology has relatively good adhesion to the metal substrate, resulting in ideal metal protection. However, metal surface alloying requires stringent conditions; some techniques need to be performed under specific inert gas environments and pressures, placing high demands on equipment and operators, limiting efficiency, and increasing operating costs. Furthermore, forming only a micron-sized alloy layer on the metal surface is insufficient to provide multiple effective protective effects; for example, it is difficult to simultaneously achieve hydrophobic and antifouling properties as well as antibacterial and friction-reducing effects.

[0007] Metal surface structure design utilizes techniques such as pulsed lasers, ultrasonic rolling, or heat treatment to create specific microstructures on the metal surface or to achieve phase transformation strengthening through grain refinement. This design cleverly leverages the friction-reducing mechanism of microtextures or the metal's own phase transformation strengthening principles, achieving good wear resistance and protection without affecting the metal surface composition. However, this technology has limited protective performance; the treated metal generally only shows some improvement in wear resistance, while its anti-fouling, antibacterial, and biofouling-resistant properties remain largely unimproved, limiting its application in complex real-world environments.

[0008] For example, existing technology provides a method for preparing a micro / nano-textured titanium nitride solid lubricating film, including the following steps: S01, pretreatment of the substrate; S02, surface texturing processing: texturing the substrate surface using a supersonic particle bombardment device; S03, preparation of the nitride layer: preparing a titanium nitride diffusion layer using an activated screen-assisted glow discharge ion nitriding method. Existing technology also provides a gradient ceramic coating microtextured self-lubricating cutting tool and its preparation method. The tool substrate material is high-speed steel or cemented carbide, and the substrate surface has a composite coating. The coating is a gradient coating consisting of alternating silicon nitride-based or alumina-based ceramic layers with added graphene, MoS2, and CaF2, and metal-ceramic layers with added graphene, MoS2, and CaF2, and the coating surface has a micro-protrusion texture. Existing technology also provides a method for preparing a micro / nano-textured coating on a diamond grinding wheel. The method involves depositing a titanium nitride coating on the textured diamond grinding wheel surface using an atmospheric plasma spraying method. The thickness of the titanium nitride coating should be less than the depth of the surface texture after texturing the grinding wheel, in order to retain the properties of the textured grinding wheel. In this invention, the titanium nitride coating on the surface of the grinding wheel can effectively reduce the wear rate of the textured grinding wheel, while improving its surface friction properties, thereby reducing the generation of cutting heat.

[0009] The aforementioned existing technologies all improve the wear resistance of the substrate through surface structure design and composition modification, but none of them mention antifouling and antibacterial properties, which is not conducive to the stability of the protective performance of the modified layer under polluted conditions.

[0010] Porous silica not only possesses characteristics such as large specific surface area, good chemical stability, good biocompatibility, and controllable pore size, but it can also accommodate a large number of guest molecules, such as biopharmaceuticals and inorganic nanoparticles, within its pores. Loading nano-silver into it can endow porous silica with antibacterial properties. However, the fine structure of porous silica, including particle size, particle shape, pore structure, and specific surface area, also affects its physical properties.

[0011] Existing technologies disclose numerous methods for synthesizing porous silica. For example, one existing method for preparing monodisperse silver-loaded mesoporous silica antibacterial powder belongs to the field of antibacterial materials technology. This method uses a quaternary ammonium salt cationic surfactant as a template and tetraethyl orthosilicate as a silicon source. Under alkaline conditions, a double-injection method is used to prepare the antibacterial powder. The resulting powder has a particle size between tens and hundreds of nanometers, and the nano-silver on the powder exhibits good dispersion while retaining the original ordered pore structure of the mesoporous silica. Another existing method for preparing a silver-loaded mesoporous silica antibacterial agent involves dissolving a template agent, a silicon source, and silver nitrate in water to obtain a silver sol. An aqueous chloride solution is then added dropwise to the silver sol, and the mixture is stirred to form a silica / silver chloride gel. The gel is dried, and then heat-treated to obtain a silver-containing mesoporous silica antibacterial agent. Existing technology discloses a silver-loaded mesoporous silica rinse-free antibacterial hand sanitizer and its preparation method, comprising the following steps: adding a skin care agent to an alcoholic substance, heating and stirring to dissolve it to form an alcohol solution; immersing mesoporous silica in a silver nitrate aqueous solution, shaking on a shaker, removing it, and freeze-drying to obtain silver-loaded mesoporous silica; adding a thickener, surfactant, and silver-loaded mesoporous silica to deionized water to form an aqueous solution; then adding the aqueous solution to the alcohol solution, and adding a pH adjuster to obtain the mesoporous silica rinse-free antibacterial hand sanitizer. The existing technology describes the structure and antibacterial properties of silver-loaded mesoporous silica antibacterial agents, utilizing the special pore structure of mesoporous silica SBA-15, and employing a method of incorporating silver during the preparation of the mesoporous carrier to synthesize the silver-loaded mesoporous silica antibacterial agent Ag / SBA-15 in one step.

[0012] However, while the porous silica-supported silver nanoparticles in the aforementioned prior art possess certain antibacterial properties, they cannot be applied to the field of metal surface modification and protection. This is because using water-based lubricants for friction reduction on metal surfaces makes it difficult to impart adequate hydrophobicity to the metal substrate, which is prone to corrosion in humid environments; therefore, oil-based lubricants are required. However, mesoporous silica surfaces contain numerous hydroxyl groups, resulting in highly hydrophilic antibacterial silica spheres. This makes them difficult to disperse uniformly in oil-based lubricants used for friction reduction, thus limiting the antibacterial and anti-adhesion effects on the metal. Summary of the Invention

[0013] The purpose of this invention is to address the problem that current protective layers are difficult to simultaneously possess wear resistance, antifouling and antibacterial properties, and prevent biofouling adhesion. This invention provides a wear-resistant, corrosion-resistant, antifouling and antibacterial composite modified layer for metal surfaces and its preparation method. This layer not only combines wear resistance and antibacterial and anti-adhesion properties, but also further improves wear resistance.

[0014] The technical solution of the present invention is as follows:

[0015] A wear-resistant, corrosion-resistant, anti-fouling, and antibacterial composite modified layer for metal surfaces includes a microtextured layer, on which a nitrided layer is disposed, and a lubricant and antibacterial silicone balls are coupled within the microtextured layer.

[0016] Preferably, the surface of the antibacterial silica sphere is covered with a layer of hydrophobic organic molecules; the pores of the antibacterial silica sphere are loaded with antibacterial particles.

[0017] Preferably, the hydrophobic organic molecule is an alkyl group.

[0018] Preferably, the antibacterial particles are nanoparticles of transition metals such as silver, copper, and zinc, or photocatalytic materials (ZrO2, TiO2).

[0019] Preferably, the particle size of the antibacterial silica spheres is 200nm to 300nm; the pore size of the antibacterial silica spheres is 3 to 10nm.

[0020] Preferably, the microtexture morphology is a recessed shape capable of storing mesoporous silicon spheres and lubricant. More preferably, it is a groove, triangle, rectangle, or mesh.

[0021] Preferably, the microtexture has a diameter of 100–200 μm and a depth of 1–10 μm.

[0022] This invention also provides a method for preparing a wear-resistant, corrosion-resistant, anti-fouling, and antibacterial composite modified layer on a metal surface, comprising the following steps:

[0023] Preparation of S1 alkylated silver-loaded mesoporous silica spheres: Hexadecyltrimethylammonium bromide, polyethylene glycol, dodecane, polyether, ammonia, and tetraethyl orthosilicate were added to an ethanol-water solution and reacted at 60°C for 2–3 h. The mixture was then washed three times each with ethanol and water by centrifugation, dried, and the template was ignited to obtain mesoporous silica spheres with controllable particle size. Finally, the obtained silver-loaded mesoporous silica spheres were uniformly dispersed in an appropriate amount of toluene, and n-octyltriethoxysilane (OTES, 0.01–0.05 parts) was added dropwise. The mixture was reacted at 60°C for 4–6 h, and the alkylated silver-loaded mesoporous silica spheres were obtained after centrifugation, washing, and drying.

[0024] S2 Design of metal surface microtexture: After cleaning the metal surface, a groove microtexture is prepared on the metal surface using a pulsed laser;

[0025] Preparation of S3 metal surface nitriding layer: The metal after laser surface microtexturing is subjected to surface ion nitriding treatment;

[0026] Construction of the S4 metal surface nano-antibacterial lubricating / microtextured / nitrided coupling layer: 0.005–0.03 parts of the prepared alkylated silver-loaded mesoporous silica spheres were ultrasonically dispersed in an appropriate amount of ethanol solution. The dispersion was then collected at a flow rate of 0.1–0.5 mL / cm³. 2The solution is dropped onto the surface of the ion-nitrided metal substrate. After the solvent evaporates, the above operation is repeated twice to ensure that a sufficient amount of alkylated silver-loaded mesoporous silicon spheres are dispersed on the substrate surface. Then, the lubricant is added at a concentration of 0.05–0.3 g / cm³. 2 The lubricant is dropped onto the substrate surface to fully wet the silicon balls; finally, the substrate is heated to 80°C and maintained for 1-2 hours, then returned to room temperature to obtain a nano-antibacterial lubricating / microtextured / nitriding coupling layer on the metal surface.

[0027] Preferably, the diameter of the metal surface microtexture in step S2 is 100-200 μm and the depth is 1-10 μm, which reduces friction and wear and improves the tribological properties of the substrate surface.

[0028] Preferably, the parameters of the pulsed laser in step S2 are: laser beam efficiency of 30% to 100%, frequency of 10 to 30 kHz, and scanning speed of 1000 to 10000 mm / s.

[0029] Preferably, in step S3, the method for preparing the nitrided layer on the metal surface is as follows: the metal sample after laser surface microtexturing treatment is placed in an ion nitriding furnace, and in a low oxygen and low humidity atmosphere, the nitrogen pressure is adjusted to 100-1000 Pa and the nitriding temperature is 300-600℃.

[0030] Preferably, in step S1, the ethanol-water solution consists of 2 parts ethanol and 3 parts water. The components include 0.02–0.05 parts hexadecyltrimethylammonium bromide, 0.03–0.09 parts polyethylene glycol (PEG-400), 0.2–0.5 parts dodecane, 0.02–0.1 parts polyether P123, 0.05–0.12 parts ammonia, and 1.0–2.0 parts tetraethyl orthosilicate.

[0031] Preferably, the dispersion is prepared at a concentration of 0.2–0.3 mL / cm³. 2 It is dropped onto the surface of a metal substrate that has undergone ion nitriding.

[0032] Preferably, the dispersion is prepared at a concentration of 0.05–0.3 g / cm³. 2 It is dropped onto the surface of the substrate.

[0033] Compared with existing technologies, the advantages of this invention are:

[0034] 1. The composite modified layer has good hydrophobic and water-repellent properties: Since the prepared functionalized mesoporous silica spheres have alkyl hydrophobic groups, they have a good loading effect on oily lubricants and impart excellent hydrophobic and water-repellent properties to the metal substrate after being coated on the surface.

[0035] 2. The composite modified layer possesses excellent wear and corrosion resistance: The nitride layer in the modified layer has strong hardness, which can significantly improve the wear resistance of the metal surface and protect the surface microtexture. At the same time, the lubricating material present on the metal surface can effectively reduce friction, and the microtexture provides a reservoir for the lubricant, reducing its loss during the friction process. The nitride layer also has a certain passivation property, which can slow down the corrosion of the metal substrate. In addition, since the modified layer has a certain water repellency, it can effectively isolate moisture from the metal substrate, giving the metal good corrosion resistance.

[0036] 3. The composite modified layer has long-lasting bactericidal and antifouling properties: The prepared functionalized mesoporous silica spheres contain silver oxide nanoparticles, which can continuously release silver ions to achieve long-lasting bactericidal performance. Combined with hydrophobicity, it can prevent the adhesion and growth of fouling organisms, ensuring the cleanliness of the substrate surface. The micro-texture in the modified layer can store the mesoporous silica spheres, ensuring that they play a long-lasting bactericidal role on the metal surface.

[0037] 4. The composite modified layer in this application has both wear resistance and corrosion resistance as well as antibacterial and anti-adhesion properties, which improves the durability of metal materials in extreme environments such as humid conditions. Attached Figure Description

[0038] Figure 1 This is a flowchart illustrating the preparation method of a wear-resistant, corrosion-resistant, anti-fouling, and antibacterial composite modified layer for metal surfaces according to this application.

[0039] Figure 2 A schematic diagram of the preparation process and morphological structure analysis of alkylated silver-loaded mesoporous silicon spheres; such as Figure 2 (a) is a schematic diagram of the preparation process of alkylated silver-loaded mesoporous silica spheres; Figure 2 (b, c, d) are characterization diagrams of the surface morphology and structure of the silicon spheres during the preparation process;

[0040] Figure 3 A schematic diagram showing the hydrophobic and antibacterial properties of alkylated silver-loaded silicon spheres;

[0041] Figure 4 This is a schematic diagram illustrating the changes in surface morphology during metal surface treatment.

[0042] Figure 5 To obtain optical micrographs of the metal surfaces before and after the treatment, after wear testing. Figure 5 (a) is an unmodified metal; Figure 5 (b) is the metal after laser micromachining / ion nitriding; Figure 5 (c) is the metal after laser micromachining / ion nitriding / lubrication; Figure 5 (d) is the metal after ion nitriding / laser micromachining; Figure 5 (e) is the metal after ion nitriding / laser micromachining / lubrication;

[0043] Figure 6The graph shows the antibacterial properties and static water contact angle data of the metal surface before and after treatment. Detailed Implementation

[0044] Unless otherwise specified, the test methods used in the following examples are conventional methods. All test materials used in the following examples are commercially available.

[0045] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0046] Example 1

[0047] according to Figure 1 The flowchart shown illustrates the preparation of a wear-resistant, corrosion-resistant, stain-resistant, and antibacterial composite modified layer for metal surfaces:

[0048] Preparation of S1 alkylated silver-loaded mesoporous silica spheres: using methods such as... Figure 2 Following the procedure in (a), 0.5 g of a 25% hexadecyltrimethylammonium bromide solution, 0.3 g of polyethylene glycol (PEG-400), 12 mL of dodecane, 2.0 g of polyether (P123), 3.2 mL of ammonia, and 10 mL of tetraethyl orthosilicate (TEOS) were added sequentially to 40 mL of an ethanol-water solution (16 mL ethanol, 24 mL water). After thorough mixing and stirring, the mixture was reacted at 60 °C for 3 h. After the reaction, the mixture was washed three times by centrifugation with ethanol and water, dried in a 60 °C oven, and then placed in a muffle furnace to calcine the template at 550 °C to obtain mesoporous silica spheres (MSNs). The structure of the prepared mesoporous silica spheres is as follows: Figure 2 As shown in (b), the internal structure exhibits a porous structure. The template-free mesoporous silica spheres obtained above were dispersed in hydrochloric acid solution for activation, followed by centrifugation, washing, and drying after 24 hours. 2.0 g of the activated mesoporous silica spheres were dispersed in 50 mL of ethanol-water solution, and 2 mL of silver nitrate solution and 1.5 mL of sodium hydroxide solution (1 g / mL) were added sequentially at 50 °C. After reacting for 2 hours, the mixture was centrifuged and washed to obtain silver-loaded mesoporous silica spheres (Ag₂O-MSNs). The structural diagram of the silver-loaded mesoporous silica spheres is shown below. Figure 2 As shown in (c), some black ions are also present in the internal channels, indicating that the negative silver oxide particles were successfully loaded. 1.0 g of the prepared silver-loaded mesoporous silica spheres were dispersed in 100 mL of toluene, and then 2.0 g of n-octyltriethoxysilane (OTES) was added dropwise to the dispersion. The reaction was carried out at 60 °C for 6 h. After centrifugation, washing, and drying, alkylated silver-loaded mesoporous silica spheres (Ag₂O-MSNs@OTES) were obtained. Figure 2 As shown in (d), the surface morphology of the silicon spheres is slightly smooth after alkylation treatment.

[0049] The alkylated silver-loaded mesoporous silica spheres prepared in this embodiment have a particle size of 220–260 nm and a pore size of 3–8 nm.

[0050] like Figure 3 The image shows the hydrophobicity and antibacterial properties of alkylated silver-loaded mesoporous silica spheres. Figure 3 (a) Optical photographs of three types of nanoparticles: Figure (I) shows MSNs, which are white powders; Figure (II) shows Ag₂O-MSNs, which are brownish powders; and Figure (III) shows Ag₂O-MSNs@OTES, which are darker in color, appearing as black powders. Figure 3 (b) When water droplets are added to Ag2O-MSNs powder, the droplets wet the powder quickly, while when added to Ag2O-MSNs@OTES powder, the droplets form ellipsoids. This shows that Ag2O-MSNs@OTES has good hydrophobicity.

[0051] like Figure 3 As shown in (c), when the concentration of Ag2O-MSNs@OTES reached 40 μg / mL, its bactericidal rate against Escherichia coli and Staphylococcus aureus both reached 99.99%; after the Ag2O-MSNs@OTES powder synthesized in this application was directly sprinkled onto an agar plate, the results were as follows. Figure 3 As shown in (d), it can be clearly seen that there is no bacterial growth in the area where Ag2O-MSNs@OTES powder is dispersed on the agar plate, which directly indicates that the synthesized alkylated silver oxide-loaded mesoporous silica spheres have excellent bactericidal effect.

[0052] Design of S2 metal surface microtexture: After cleaning the metal surface, a pulsed laser is used with the laser beam efficiency adjusted to 80%, the frequency to 30kHz, and the scanning speed to 10000mm / s to construct a groove microtexture on the metal surface; the morphology of the metal substrate surface after processing is as follows. Figure 4 As shown in (a).

[0053] Preparation of the S3 metal surface nitriding layer: The metal sample, after laser surface microtexturing treatment, was placed in an ion nitriding furnace. In a low-oxygen, low-humidity atmosphere, the nitrogen pressure was controlled at 200 Pa, and the nitriding temperature at 450℃ to construct a nitriding layer on the metal surface. The surface of the nitrided metal substrate is as follows: Figure 4 As shown in (b).

[0054] Construction of the S4 metal surface nano-antibacterial lubricating / microtextured / nitrided coupling layer: Weigh 0.5g of the above-mentioned alkylated silver-loaded mesoporous silica spheres and ultrasonically disperse them in 20mL of ethanol solution to a concentration of 25000μg / mL. Then, take 2mL of the dispersion and disperse it at 0.2mL / cm 2 The solution is dropped onto the surface of the ion-nitrided metal substrate; after the solvent evaporates, the above operation is repeated twice to ensure that a sufficient amount of alkylated silver-loaded mesoporous silicon spheres are dispersed on the substrate surface; then the lubricant is added at a rate of 0.1 g / cm³. 2The lubricant is dropped onto the substrate surface to fully wet the silicon balls; finally, the substrate is heated to 80°C, kept for 2 hours, and then returned to room temperature to obtain a nano-antibacterial lubricating / microtextured / nitriding coupling layer on the metal surface.

[0055] Example 2

[0056] A wear-resistant, corrosion-resistant, anti-fouling, and antibacterial composite modified layer for metal surfaces is prepared according to the following method:

[0057] Preparation of S1 alkylated silver-loaded mesoporous silica spheres: In 40 mL of ethanol-water solution (16 mL ethanol, 24 mL water), 0.5 g of 25% hexadecyltrimethylammonium bromide solution, 0.3 g of polyethylene glycol (PEG-400), 12 mL of dodecane, 2.0 g of polyether (P123), 3.2 mL of ammonia, and 8.0 mL of tetraethyl orthosilicate were added sequentially. After thorough mixing and stirring, the mixture was reacted at 60 °C for 3 h. After the reaction was completed, the spheres were washed three times by centrifugation with ethanol and water, dried in a 60 °C oven, and then placed in a muffle furnace to ignite the template at 550 °C to obtain mesoporous silica spheres. The template-free mesoporous silica spheres obtained above were dispersed in hydrochloric acid solution for activation, and then centrifuged, washed, and dried after 24 h. 2.0 g of activated mesoporous silica spheres were dispersed in 50 mL of ethanol-water solution. 2 mL of silver nitrate solution and 1.5 mL of sodium hydroxide solution (1 g / mL) were added sequentially at 50 °C. After reacting for 2 h, the mixture was centrifuged and washed to obtain silver-loaded mesoporous silica spheres. Finally, 1.0 g of the silver-loaded mesoporous silica spheres obtained above were weighed and dispersed in 100 mL of toluene. Then, 2.0 g of n-octyltriethoxysilane (OTES) was added dropwise to the dispersion. The mixture was reacted at 60 °C for 6 h. After centrifugation, washing, and drying, alkylated silver-loaded mesoporous silica spheres were obtained.

[0058] The alkylated silver-loaded mesoporous silicon spheres prepared in this embodiment have a particle size of 240–280 nm and a pore size of 4–8 nm.

[0059] Preparation of S2 metal surface nitriding layer: The metal sample is placed in an ion nitriding furnace. In a low oxygen and low humidity atmosphere, the nitrogen pressure is adjusted to 200 Pa and the nitriding temperature is 600 °C to construct a nitriding layer on the metal surface.

[0060] Design of S3 metal surface microtexture: After cleaning the ion-nitrided metal surface, a pulsed laser was used to construct a grooved microtexture on the metal surface, with the laser beam efficiency adjusted to 30%, the frequency to 30kHz, and the scanning speed to 10000mm / s. The morphology after nitriding followed by microtexturing is as follows: Figure 4 As shown in (c), it can be seen that pitted microtextures can still appear on the surface of the metal nitride layer.

[0061] Construction of the S4 metal surface nano-antibacterial lubricating / microtextured / nitrided coupling layer: Weigh 0.5g of the above-mentioned alkylated silver-loaded mesoporous silica spheres and ultrasonically disperse them in 20mL of ethanol solution to a concentration of 25000μg / mL. Then, take 2mL of the solution and disperse it at a concentration of 0.2mL / cm. 2 The dispersion was dropwise added to the surface of the ion-nitrided metal substrate; after the solvent evaporated, the above operation was repeated twice to ensure that a sufficient amount of functionalized silicon spheres were dispersed on the substrate surface; then, at a rate of 0.1 g / cm³, the dispersion was applied. 2 Lubricant is dropped onto the substrate surface to fully wet the silicon spheres; finally, the substrate is heated to 80°C, kept for 2 hours, and then returned to room temperature to obtain a nano-antibacterial lubricating / microtextured / nitriding coupling layer on the metal surface.

[0062] Example 3

[0063] A wear-resistant, corrosion-resistant, anti-fouling, and antibacterial composite modified layer for metal surfaces is prepared according to the following method:

[0064] Preparation of S1 alkylated silver-loaded mesoporous silica spheres: 1) In 40 mL of ethanol-water solution (16 mL ethanol, 24 mL water), 0.5 g of 25% hexadecyltrimethylammonium bromide solution, 0.4 g of polyethylene glycol (PEG-400), 15 mL of dodecane, 2.0 g of polyether (P123), 3.5 mL of ammonia, and 16 mL of tetraethyl orthosilicate were added sequentially. After thorough mixing and stirring, the mixture was reacted at 60 °C for 3 h. After the reaction was completed, the mixture was washed three times by centrifugation with ethanol and water, dried in a 60 °C oven, and then placed in a muffle furnace to ignite the template at 550 °C to obtain mesoporous silica spheres. The template-free mesoporous silica spheres obtained above were dispersed in hydrochloric acid solution for activation, and then centrifuged, washed, and dried after 24 h. 2.0 g of activated mesoporous silica spheres were dispersed in 50 mL of ethanol-water solution. 2 mL of silver nitrate solution and 1.5 mL of sodium hydroxide solution (1 g / mL) were added sequentially at 50 °C. After reacting for 2 h, the mixture was centrifuged and washed to obtain silver-loaded mesoporous silica spheres. Finally, 1.0 g of the silver-loaded mesoporous silica spheres obtained above were weighed and dispersed in 100 mL of toluene. Then, 3.0 g of n-octyltriethoxysilane (OTES) was added dropwise to the dispersion. The mixture was reacted at 60 °C for 6 h. After centrifugation, washing, and drying, alkylated silver-loaded mesoporous silica spheres were obtained.

[0065] The alkylated silver-loaded mesoporous silicon spheres prepared in this embodiment have a particle size of 250–280 nm and a pore size of 5–10 nm.

[0066] S2 Design of metal surface microtexture: After cleaning the metal surface, a pulsed laser is used to construct a groove microtexture on the metal surface by adjusting the laser beam efficiency to 80%, the frequency to 30kHz, and the scanning speed to 10000mm / s.

[0067] Preparation of S3 metal surface nitriding layer: The metal sample after laser surface microtexturing treatment is placed in an ion nitriding furnace. In a low oxygen and low humidity atmosphere, the nitrogen pressure is adjusted to 200 Pa and the nitriding temperature is 300 °C to construct a nitriding layer on the metal surface.

[0068] Construction of the S4 metal surface nano-antibacterial lubricating / microtextured / nitrided coupling layer: Weigh 0.5g of the above-mentioned alkylated silver-loaded mesoporous silica spheres and ultrasonically disperse them in 20mL of ethanol solution. Then, take 2mL of the dispersion and drop it onto the surface of the ion-nitrided metal substrate (0.3mL / cm). 2 After the solvent evaporates, repeat the above operation twice to ensure that a sufficient amount of functionalized silicon spheres are dispersed on the substrate surface; then add lubricant dropwise onto the substrate surface to fully wet the silicon spheres (0.2 g / cm³). 2 Finally, the substrate is heated to 80°C and held for 2 hours, then allowed to return to room temperature to obtain the nano-antibacterial lubricating / microtexture / nitriding coupling layer on the metal surface.

[0069] The data for Example 3 are almost identical to those for Example 1.

[0070] Under a 4N load, a reciprocating wear test was conducted on the untreated metal surface and the metal test materials prepared in Examples 1 and 2 using a 6mm grinding ball. The results are as follows: Figure 5 As shown. Among them. Figure 5 (a) is untreated metal. As can be seen from the figure, the untreated technical surface is extremely easy to wear, and the wear area is very large. Figure 5 (b) is the metal after microtexturing design and nitride layer application in Example 1 (step S3). As can be seen from the figure, the wear-marked area is relatively... Figure 5 (a) Significantly reduced; Figure 5 (c) shows the wear test results after coupling the lubricant in step S4 of Example 1. As can be seen from the figure, the wear area is relatively... Figure 5 (b) Further reduction, with almost no wear marks on the metal surface; it is evident that the surface modification method of this application significantly improves the wear resistance of the metal surface.

[0071] Furthermore, the material prepared in Example 2 after adjusting the order of nitride layer preparation and microtexture design was also subjected to wear tests, and the experimental phenomena were as follows: Figure 5 (d) and Figure 5 As shown in (e), Figure 5 (d) shows the metal surface after only microtexturing design and nitriding layer application, with similar wear marks. Figure 5 (b); Figure 5 (e) shows the wear test results of Example 2 after coupling the lubricant in step S4, and the wear marks are similar. Figure 5 (e) shows that changing the order of the two does not significantly affect the wear resistance of the metal.

[0072] The above data shows that the composite modified layer designed in this invention can effectively improve the friction reduction and wear resistance of the metal substrate surface, slow down the wear of the passivation layer on the substrate surface, and thus avoid accelerated corrosion of the metal after wear occurs in local areas.

[0073] Testing the antibacterial properties of metal surfaces before and after treatment:

[0074] The test samples were immersed in the prepared 10 5 CFU mL -1 After standing for 3 minutes in Escherichia coli and Staphylococcus aureus bacterial suspensions, the test samples were removed and transferred to liquid culture medium, and incubated at 37°C for 24 hours. Following incubation, the test samples were placed in an appropriate amount of phosphate-buffered saline (PBS), sonicated in a water bath for 10 minutes, and then 100 μL was spin-spread onto LB agar plates and incubated at 37°C for 24 hours. Finally, the antibacterial activity of the test samples was calculated by plate colony counting.

[0075] like Figure 6 The figure shows the antibacterial properties and static water contact angle of the metal surface before and after treatment. Figure 6 (a) and Figure 6 (c) The metal surface has not undergone functional modification. The corresponding agar plate is covered with bacterial colonies, indicating that it is ineffective against *E. coli* and *S. aureus*. The agar plate is covered with bacteria. Figure 6 (b) and Figure 6 (d) shows the surface of the metal substrate with the composite modified layer in Example 1. No bacteria grew on the corresponding agar plates, indicating its excellent bactericidal properties. Figure 6 As shown in (e), its killing effect on Escherichia coli and Staphylococcus aureus reached 99.9%, demonstrating good antifouling and antibacterial properties.

[0076] like Figure 6 As shown in (f), the static water contact angle test further demonstrates that, compared with the original substrate, the nitrided metal substrate, and the nitrided / microtextured metal substrate, the surface of the metal substrate containing the composite modified layer has a good water repellency effect, with a static water contact angle of up to 118±3°, which can effectively slow down the corrosion of metal in humid environments.

[0077] In summary, this invention constructs a nano-antibacterial lubricating / microtextured / nitrided composite modified layer on the metal surface by sequentially performing laser micromachining, ion nitriding, and coating with a lubricant containing alkylated silver oxide-supported mesoporous silica spheres. This process imparts long-lasting wear resistance, corrosion resistance, and antifouling and antibacterial properties to the metal surface, making it an excellent metal surface modification technology.

[0078] Example 4

[0079] This embodiment provides a wear-resistant, corrosion-resistant, anti-fouling, and antibacterial composite modified layer for metal surfaces, including a microtextured layer, a nitrided layer disposed on the microtextured layer, and a lubricant and antibacterial silicone balls coupled within the microtextured layer.

[0080] Preferably, the surface of the antibacterial silica sphere is covered with a layer of hydrophobic organic molecules; the pores of the antibacterial silica sphere are loaded with antibacterial particles.

[0081] Preferably, the hydrophobic organic molecule is an alkyl group.

[0082] Preferably, the antibacterial particles are nanoparticles of transition metals such as silver, copper, and zinc, oxides, or photocatalytic materials (ZrO2, TiO2).

[0083] Preferably, the microtexture morphology is a recessed shape capable of storing mesoporous silicon spheres and lubricant. More preferably, it is a groove, triangle, rectangle, or mesh.

[0084] Preferably, the microtexture has a diameter of 100–200 μm and a depth of 1–10 μm.

[0085] Preferably, the antibacterial silica spheres have a particle size of 200–300 nm. This allows for the containment of more than 40 μg / mL of antibacterial silica spheres within the microtexture, ensuring the antibacterial performance of the wear-resistant, corrosion-resistant, stain-resistant, and antibacterial composite modified layer on the metal surface.

[0086] Preferably, when the antibacterial particles are silver oxide nanoparticles, the pore size of the antibacterial silica spheres is 3-10 nm.

[0087] The embodiments described above merely illustrate specific implementation methods of this application, and while the descriptions are detailed and specific, they should not be construed as limiting the scope of protection of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the technical solution of this application, and these modifications and improvements all fall within the scope of protection of this application.

Claims

1. A composite modified layer for metal surfaces that is wear-resistant, corrosion-resistant, stain-resistant, and antibacterial, characterized in that, It includes a microtextured layer, on which a nitrided layer is disposed, and a lubricant and antibacterial silica spheres are coupled within the microtextured layer; the diameter of the microtexture is 100 ~ 200 μm and the depth is 1 ~ 10 μm; the particle size of the antibacterial silica spheres is 200 nm ~ 300 nm.

2. The wear-resistant, corrosion-resistant, stain-resistant, and antibacterial composite modified layer for metal surfaces according to claim 1, characterized in that, The surface of the antibacterial silica sphere is covered with a layer of hydrophobic groups; the pores of the antibacterial silica sphere are loaded with antibacterial particles.

3. The wear-resistant, corrosion-resistant, stain-resistant, and antibacterial composite modified layer for metal surfaces according to claim 2, characterized in that, The hydrophobic groups on the surface of the antibacterial silica spheres are alkyl chains.

4. The wear-resistant, corrosion-resistant, stain-resistant, and antibacterial composite modified layer for metal surfaces according to claim 2, characterized in that, The antibacterial particles are silver oxide nanoparticles, and the pore size of the antibacterial silica spheres is 3 to 10 nm.

5. A method for preparing a wear-resistant, corrosion-resistant, anti-fouling, and antibacterial composite modified layer for metal surfaces as described in any one of claims 1 to 4, characterized in that, Includes the following steps: Preparation of S1 alkylated silver-loaded mesoporous silica spheres: Mesoporous silica spheres with controllable particle size were prepared. The prepared silver-loaded mesoporous silica spheres were uniformly dispersed in an appropriate amount of toluene, and n-octyltriethoxysilane was added dropwise. After reaction, centrifugation, washing and drying were performed to obtain alkylated silver-loaded mesoporous silica spheres. S2 Design of metal surface microtexture: After cleaning the metal surface, a groove microtexture is prepared on the metal surface using a pulsed laser; Preparation of S3 metal surface nitriding layer: The metal is subjected to surface ion nitriding treatment; Construction of the S4 metal surface nano-antibacterial lubricating / microtexturing / nitriding coupling layer: The prepared alkylated silver-loaded mesoporous silica spheres were ultrasonically dispersed in an appropriate amount of ethanol solution. Then, the dispersion was taken and dropped onto the surface of the metal substrate after microtexturing and nitriding layer treatment, and the solvent was allowed to evaporate. Then, the lubricant was dropped onto the substrate surface to fully wet the silica spheres. Finally, the substrate was heated to promote particle dispersion.

6. The method for preparing a wear-resistant, corrosion-resistant, anti-fouling, and antibacterial composite modified layer for metal surfaces according to claim 5, characterized in that, The order of steps S2 and S3 is reversed.

7. The method for preparing a wear-resistant, corrosion-resistant, anti-fouling, and antibacterial composite modified layer for metal surfaces according to claim 5, characterized in that, In step S4, the concentration of alkylated silver-loaded mesoporous silica spheres in the dispersion is greater than or equal to 40 μg / mL, and the dispersion is prepared at a concentration of 0.1 ~ 0.5 mL / cm³. 2 It is dropped onto the surface of a metal substrate that has undergone ion nitriding.

8. The method for preparing a wear-resistant, corrosion-resistant, anti-fouling, and antibacterial composite modified layer for metal surfaces according to claim 5, characterized in that, The lubricant is applied at a concentration of 0.05 ~ 0.3 g / cm³. 2 It is dropped onto the surface of the substrate.

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