Micro-nano diamond reinforced corrosion and wear resistant coating, and preparation method and application thereof

Abstract

The application discloses a kind of micro-nano diamond reinforced corrosion-resistant and wear-resistant coating and its preparation method and application.The preparation method includes: using silane coupling agent to carry out surface functionalization treatment to micro-sized diamond particles and nano-sized diamond particles respectively by hydrolysis reaction;Epoxy resin, the micro-sized diamond particles and nano-sized diamond particles after surface functionalization treatment, organic solvent, activator and curing agent are mixed uniformly, then coated on the surface of substrate, solidified, to obtain micro-nano diamond reinforced corrosion-resistant and wear-resistant coating.The coating prepared by the application has non-smooth surface structure, excellent corrosion resistance and wear resistance, and can be applied to the protection of substrate surface in harsh environment.

Description

Technical Field

[0001] This invention belongs to the field of surface engineering technology, specifically relating to a micro / nano diamond-reinforced corrosion-resistant and wear-resistant coating, its preparation method, and its application. Background Technology

[0002] Epoxy resin (EP) coatings are widely used for corrosion protection of metallic materials due to their excellent adhesion, good chemical stability, and ease of application. However, pure epoxy resin, after curing, has a high cross-linking density and high internal stress, resulting in brittleness and poor impact and wear resistance. In harsh working conditions involving friction and erosion, such as drilling, marine engineering, and mechanical transmission, pure epoxy resin coatings are prone to failure due to wear, leading to the loss of their protective barrier function and corrosion of the base metal. Therefore, relying solely on epoxy resin coatings can no longer meet the dual service requirements of "wear resistance" and "corrosion resistance" under complex working conditions.

[0003] To improve the wear resistance of epoxy resin coatings, existing technologies commonly employ the addition of micron- or nano-sized hard particles. These particles utilize a dispersion strengthening effect to enhance the coating's hardness, scratch resistance, and wear resistance. For example, micron-sized ceramic particles (such as alumina and silicon carbide) or nanoparticles (such as silica and carbon nanotubes) are introduced into the epoxy resin matrix. Diamond, as the hardest natural substance, is an ideal wear-resistant filler. Nanodiamonds, in particular, theoretically offer significant performance improvements to coatings due to their excellent mechanical properties and large specific surface area.

[0004] However, existing technologies still have the following shortcomings in achieving epoxy coatings with both excellent wear resistance and corrosion resistance: (1) Limitations of single-scale particle reinforcement: Although adding only micron-sized particles can improve the macroscopic hardness of the coating, it is easy to cause defects inside the coating, and the barrier performance against corrosive media is limited. (2) Nanodiamond particles are very easy to form strong agglomerates, and it is difficult to achieve uniform and stable dispersion in the epoxy resin matrix. When the amount added exceeds a certain threshold, the agglomeration phenomenon will deteriorate sharply, leading to an increase in internal defects in the coating. The friction and wear performance and corrosion protection performance of the composite coating will decrease instead of increase, which seriously restricts the efficient application of nanodiamonds in wear-resistant and corrosion-resistant coatings. (3) Interface bonding problem: The interface compatibility between diamond particles and organic epoxy resin matrix is ​​poor. The untreated particle surface lacks effective chemical bonding with the resin, and is only physically interlocked. When subjected to external friction or corrosion, the interface area is prone to become a weak link, causing particles to fall off and accelerating coating failure.

[0005] For example, patent CN 118126498 A discloses a modified diamond micron epoxy resin composite material and its preparation method. It uses a silane coupling agent to modify the surface of diamond micron powder (particle size 0.1~10μm), and then mixes and cures it with epoxy resin and a curing agent to create a composite material to improve wear resistance. However, while individual micron particles can bear loads and block abrasive particles, their interface with the matrix is ​​relatively weak, making them prone to detachment during wear. These detached particles then become "third-body abrasive particles," exacerbating wear. While individual nanoparticles can strengthen the matrix, their small size and tendency to agglomerate make them unable to bear macroscopic loads. Furthermore, the low filling rate of single-particle sizes leads to high water absorption and insufficient corrosion resistance. Although existing technology CN 118290894 A provides a solution that mixes micron and nano diamond particles, it primarily focuses on the heat dissipation direction of the polymer and does not improve the wear and corrosion resistance of the epoxy coating.

[0006] In summary, developing an epoxy coating and its preparation method that can fully leverage the synergistic enhancement effect of micron and nanodiamond particles while effectively addressing the issues of nanodiamond agglomeration and its interfacial bonding with the resin matrix is ​​of great significance for improving the wear and corrosion resistance of coatings under harsh environments. Summary of the Invention

[0007] The main objective of this invention is to provide a micro / nano diamond-reinforced corrosion-resistant and wear-resistant coating, its preparation method, and its application, so as to overcome the shortcomings of the prior art.

[0008] To achieve the aforementioned objectives, the technical solution adopted by this invention includes: The first aspect of the present invention provides a method for preparing a micro / nano diamond-reinforced corrosion-resistant and wear-resistant coating, comprising: performing surface functionalization treatment on micron-sized diamond particles and nano-sized diamond particles respectively by hydrolysis reaction using a silane coupling agent; Epoxy resin, surface-functionalized micron-sized diamond particles, surface-functionalized nano-sized diamond particles, organic solvent, activator and curing agent are mixed evenly, then coated on the substrate surface and cured to obtain a micro / nano diamond-reinforced corrosion-resistant and wear-resistant coating.

[0009] A second aspect of the present invention provides a micro / nano diamond-reinforced corrosion-resistant and wear-resistant coating prepared by the above-described preparation method, which has a non-smooth surface structure.

[0010] A third aspect of the invention provides the application of the micro / nano diamond-reinforced corrosion-resistant and wear-resistant coating in the protection of a substrate surface, the substrate comprising at least a partial surface of a drilling, marine engineering, or mechanical transmission component.

[0011] A fourth aspect of the present invention provides a corrosion-resistant and wear-resistant device comprising a substrate and a micro / nano diamond-reinforced corrosion-resistant and wear-resistant coating applied to the surface of the substrate.

[0012] Compared with the prior art, the present invention has at least the following beneficial effects: (1) The present invention uses APTS silane coupling agent to modify the surface of micro / nano diamond particles; the diamond is modified by APTS, and the functional groups connected on the surface effectively prevent the agglomeration between diamond particles, and significantly improve its compatibility and dispersibility in epoxy resin coating. (2) The present invention uses micro-nano diamond-level coordination to form a non-smooth surface on the coating surface that is similar to the "dung beetle head shell" to reduce adhesion and drag. In addition, diamond itself has a large contact angle with water, which makes the coating extremely hydrophobic. (3) The present invention utilizes the high hardness of diamond and the strong interfacial bonding force after surface silanization treatment, which enables the added micro / nano diamond particles to suppress the generation and propagation of cracks during dry friction, thus significantly reducing the wear rate of the coating. In addition, the detached spherical nanodiamonds will produce a polishing effect, making the surface of the wear marks smoother, reducing the coefficient of friction, and improving the wear resistance of the coating; (4) The present invention improves the density of epoxy resin coating by adding micro / nano diamond particles, and nano diamond can occupy the gaps between micro diamonds, hindering the penetration of liquid and significantly slowing down the diffusion of corrosive media to the substrate, thus exhibiting better barrier and corrosion protection performance. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a schematic diagram of the hydrolysis reaction in a typical embodiment of the present invention; Figure 2 This is a surface morphology diagram of the micro / nano diamond-reinforced epoxy coating prepared in Example 1 of this invention; Figure 3 This is a surface morphology diagram of the epoxy coating prepared in Comparative Example 1 of the present invention; Figure 4 This is a surface morphology diagram of the micron-diamond-reinforced epoxy coating prepared in Comparative Example 2 of this invention; Figure 5 This is a comparison chart of the wear amount of the coatings prepared in Example 1, Comparative Example 1 and Comparative Example 2 of the present invention; Figure 6 This is a comparison chart of the water absorption rates of the coatings prepared in Example 1, Comparative Example 1, and Comparative Example 2 of the present invention in a 3.5 wt.% sodium chloride solution. Detailed Implementation

[0015] In view of the problems existing in the above-mentioned prior art, after in-depth research, a micro-nano diamond-reinforced corrosion-resistant and wear-resistant coating, its preparation method and application are provided.

[0016] The following will provide a further explanation of the technical solution, its implementation process, and its principles.

[0017] The first aspect of the present invention provides a method for preparing a micro / nano diamond-reinforced corrosion-resistant and wear-resistant coating, comprising: using a silane coupling agent to perform surface functionalization treatment on micron-sized diamond particles and nano-sized diamond particles respectively through a hydrolysis reaction; Epoxy resin, surface-functionalized micron-sized diamond particles, surface-functionalized nano-sized diamond particles, organic solvent, activator and curing agent are mixed evenly, then coated on the substrate surface and cured to obtain a micro / nano diamond-reinforced corrosion-resistant and wear-resistant coating.

[0018] In some embodiments, the preparation method specifically includes: adding the micron-sized diamond particles, nano-sized diamond particles, and silane coupling agent to an anhydrous alcohol solvent, ultrasonically treating to form a uniformly dispersed mixed system, then adding water to the mixed system, and carrying out the hydrolysis reaction at 70~90°C for 3~5 hours to complete the surface functionalization treatment.

[0019] Furthermore, the mass ratio of the micron-sized diamond particles, nano-sized diamond particles, silane coupling agent, anhydrous alcohol solvent, and water is 0.5:0.1:1~3:80~90:5~10.

[0020] Furthermore, the anhydrous alcohol solvent includes, but is not limited to, anhydrous ethanol.

[0021] In some embodiments, the preparation method specifically includes: adding the epoxy resin to the epoxy resin, dissolving the epoxy resin in an organic solvent, adding an activator, then adding surface-functionalized micron-sized diamond particles and surface-functionalized nano-sized diamond particles, magnetically stirring at a speed of 200~300 r / min for 25~35 min, then adding a curing agent and continuing to stir for 15~25 min to obtain a mixed slurry.

[0022] Furthermore, the mass ratio of the epoxy resin, organic solvent, activator, and curing agent is 10:2~4:0.5~2:4.

[0023] Furthermore, the mass ratio of the surface-functionalized micron-sized diamond particles, the surface-functionalized nano-sized diamond particles, and the epoxy resin is 2~5:0.1~0.5:8~15.

[0024] In some embodiments, the preparation method specifically includes: vacuum defoaming the mixed slurry, then spraying the vacuum defoamed mixed slurry onto the substrate surface, and curing it at 50~80 ℃ for 8~16 h to obtain the micro-nano diamond-reinforced corrosion-resistant and wear-resistant coating.

[0025] Furthermore, the vacuum defoaming includes: maintaining the mixed slurry in a vacuum-sealed environment of 3-5 Pa for 10-20 minutes to remove air bubbles.

[0026] Furthermore, the preparation method specifically includes: cleaning the surface of the substrate, using a spraying device, using compressed air at 0.4~0.8 MPa for 3~6 s, with the distance between the substrate and the spraying device being 10~30 cm, and spraying the vacuum-defoamed mixed slurry onto the surface of the substrate.

[0027] For example, the spraying apparatus used in this invention includes a spray gun, but is not limited thereto.

[0028] In some embodiments, the average particle size of the micron-sized diamond particles is 3 to 7 μm.

[0029] In some embodiments, the average particle size of the nanoscale diamond particles is 3 to 7 nm.

[0030] In some embodiments, the silane coupling agent includes, but is not limited to, at least one of 3-aminopropyltriethoxysilane and 3-aminopropyltrimethoxysilane.

[0031] In some embodiments, the epoxy resin includes at least one of bisphenol A type epoxy resin and bisphenol F type epoxy resin, but is not limited thereto.

[0032] In some embodiments, the organic solvent includes at least one of xylene, ethyl acetate, and propylene glycol, but is not limited thereto.

[0033] In some embodiments, the activator includes, but is not limited to, polydimethylsiloxane.

[0034] In some embodiments, the curing agent includes, but is not limited to, T31 curing agent.

[0035] In some more specific embodiments, the preparation method of the micro / nano diamond-reinforced corrosion-resistant and wear-resistant coating specifically includes the following steps: (1) Surface functionalization of micron-sized diamond particles (MD) and nano-sized diamond particles (ND) was carried out by hydrolysis reaction using 3-aminopropyltriethoxysilane (APTS), followed by washing and drying; (2) Add the surface-functionalized micron-sized diamond particles (MD) and nano-sized diamond particles (ND) to the epoxy resin, using xylene as an organic solvent, polydimethylsiloxane as an activator, and T31 reagent as a curing agent, and stir thoroughly. (3) After vacuum defoaming, the coating is applied to the metal substrate using a spray gun and cured to obtain a micro-nano diamond-reinforced corrosion-resistant and wear-resistant epoxy coating.

[0036] Furthermore, the average particle size of the micron-sized diamond in step (1) is 3~7 μm, and the average particle size of the nano-sized diamond particles is 3~7 nm.

[0037] Further, the hydrolysis reaction in step (1) involves adding micro / nano diamond particles and APTS to anhydrous ethanol, homogenizing the mixture by ultrasonic treatment, and then stirring at 70-90°C for 3-5 hours. Simultaneously, distilled water is slowly added to the solution. The mass ratio of the micron-sized diamond particles, [u1.1]silane coupling agent, anhydrous alcohol solvent, and water is 0.5:1-3:80-90:5-10; the mass ratio of the nano-sized diamond particles, silane coupling agent, anhydrous alcohol solvent, and water is 0.1:1-3:80-90:5-10.

[0038] Further, the filtration and drying process in step (1) involves filtration and washing five times with anhydrous ethanol, followed by drying in an oven at 180~220℃ for 20~30 hours to remove residual APTS, water and ethanol.

[0039] Further, in step (2), epoxy resin is dissolved in the organic solvent xylene, and the activator polydimethylsiloxane is added. The mass ratio of epoxy resin, xylene and polydimethylsiloxane is 10:2~4:0.5~2. The mass ratio of the surface-functionalized micron-sized diamond particles, the surface-functionalized nano-sized diamond particles and epoxy resin is 2~5:0.1~0.5:8~15.

[0040] Further, the stirring process in step (2) is magnetic stirring, with a speed of 200-300 r / min and a stirring time of 25-35 minutes. After adding T31 curing agent, stirring is continued for 15-25 minutes. The weight ratio of T31 curing agent to epoxy resin is 4:10.

[0041] Furthermore, the defoaming method described in step (3) involves placing the suspension in a vacuum tank with a pressure of 3-5 Pa for 10-20 minutes to remove air bubbles.

[0042] Furthermore, the spraying method described in step (3) is characterized in that: the substrate surface is rinsed with deionized water for 1 to 2 minutes to remove dust, compressed air of 0.4 to 0.8 MPa is used for spraying for 3 to 6 seconds, and the distance between the sample and the spray gun is 10 to 30 cm.

[0043] Furthermore, the curing method described in step (3) is characterized in that: the coating is cured at a temperature of 50~80 ℃ for 8~16 hours in a forced-air drying oven to obtain a micro-nano diamond-reinforced corrosion-resistant and wear-resistant coating with a coating thickness of 15~40μm.

[0044] Specifically, the mechanism of the micro / nano diamond-reinforced corrosion-resistant and wear-resistant coating of the present invention is explained as follows: Firstly, at the particle packing level, this invention employs a blend of micron- and nano-sized diamond powders, forming a continuous particle size distribution. Micron-sized diamond powders constitute the hard, load-bearing framework of the coating, while nano-sized diamond powders fill the gaps between micron-sized particles and the micropores formed by the curing shrinkage of the epoxy resin. This significantly increases the packing density of the hard phase, reduces the coating porosity, and minimizes resin-rich areas and internal defects. Compared to single-size fillers, which are difficult to densely fill due to the large number of voids between particles, the micro-nano synergistic system of this invention achieves a more dense structure at the same filler content, laying the foundation for the simultaneous improvement of the coating's wear and corrosion resistance.

[0045] Secondly, regarding the wear resistance mechanism, micron-sized diamond powder, with its high hardness and high modulus, acts as the main anti-wear skeleton, bearing the compressive stress and abrasive wear during the wear process, and reducing the direct wear contact with the epoxy resin matrix through convex support. Nano-sized diamond powder, on the other hand, is dispersed throughout the matrix, improving the micro-area hardness and stiffness of the matrix, and playing a role in crack deflection and pinning under external loads or crack propagation, dissipating energy step by step and inhibiting the initiation and propagation of microcracks. Simultaneously, the surface-modified diamond powder forms a strong interfacial bond with the epoxy resin, effectively inhibiting the overall shedding of micron-sized particles during wear, preventing detached particles from transforming into third-body abrasive particles and exacerbating wear, thereby significantly reducing the coating wear rate and maintaining a stable coefficient of friction.

[0046] Thirdly, regarding the corrosion resistance mechanism, the coating of this invention relies on a multi-level barrier effect and the extension of the diffusion path to block corrosive media. Micron-sized diamond powder forms a large-scale, tortuous diffusion path, forcing corrosive media such as water, oxygen, and chloride ions to penetrate around it. Nano-sized diamond powder further fills and seals the nanoscale interconnected channels remaining between micron-sized particles and the micropores and microcracks within the matrix. Together, they construct a multi-level dense barrier, significantly extending the penetration path of corrosive media and reducing the coating's water absorption and permeability. Compared to the shortcomings of single micron-sized fillers due to interconnected channels between particles, and single nano-sized fillers due to easy agglomeration and the resulting penetration defects, the micro-nano synergistic structure of this invention can more effectively hinder the diffusion of corrosive media into the matrix, thereby significantly improving the coating's corrosion resistance.

[0047] Fourth, after modification treatment with coupling agents, the surface of diamond micropowder introduces functional groups that can chemically react with epoxy resin or form strong interactions, improving the dispersibility of diamond micropowder in the resin and strengthening the interfacial bonding between the two phases. This strong interface, on the one hand, improves the efficiency of load transfer from the matrix to the hard phase, enhancing load-bearing and wear resistance; on the other hand, it eliminates the channels for corrosive media penetration formed by interfacial defects, further improving the density and corrosion resistance of the coating.

[0048] Therefore, this invention achieves a reasonable allocation and synergistic effect of multiple functions such as load-bearing skeleton, matrix strengthening, interface locking and pore sealing at different scales by synergistically distributing the particle size distribution of micron and nano diamond powders and combining them with the strong interfacial bonding established by surface modification. This results in a coating that is significantly superior to coatings using diamond powder of a single particle size in terms of wear resistance and corrosion resistance.

[0049] A second aspect of the present invention provides a micro / nano diamond-reinforced corrosion-resistant and wear-resistant coating prepared by the above-described preparation method, which has a non-smooth surface structure.

[0050] Specifically, the coating has a non-smooth surface that can reduce stickiness and drag, a contact angle of 100~140°, good hydrophobicity, and significantly improved hardness compared with epoxy resin coating.

[0051] In some embodiments, the thickness of the micro-nano diamond-reinforced corrosion-resistant and wear-resistant coating is 15~40 μm.

[0052] In some embodiments, the surface roughness of the micro / nano diamond-reinforced corrosion-resistant and wear-resistant coating is 2 to 8 micrometers.

[0053] In some embodiments, the water absorption of the micro / nano diamond-reinforced corrosion-resistant and wear-resistant coating is less than 5%.

[0054] In some embodiments, the wear rate of the micro / nano diamond-reinforced corrosion-resistant and wear-resistant coating is 10. -4 mm3 N 1 m 1 the following.

[0055] The third aspect of the present invention provides the application of the micro / nano diamond-reinforced corrosion-resistant and wear-resistant coating in the protection of a substrate surface, the substrate comprising at least a partial surface of a drilling, marine engineering, or mechanical transmission component.

[0056] A fourth aspect of the present invention provides a corrosion-resistant and wear-resistant device comprising a substrate and a micro / nano diamond-reinforced corrosion-resistant and wear-resistant coating applied to the surface of the substrate.

[0057] The technical solution of the present invention will be further described below with reference to the embodiments. Where specific experimental steps or conditions are not specified in the embodiments, they can be performed according to the conventional experimental steps or conditions described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available. Other unmentioned raw materials and instruments are all conventionally selected and do not involve the core technical means of the present invention.

[0058] Example 1 This embodiment includes the following steps: Step 1, such as Figure 1 As shown, 0.5 g of micron-sized diamond particles (MD) with an average particle size of 5 μm and 0.1 g of nano-sized diamond particles (ND) with an average particle size of 5 nm were mixed with 2 g of 3-aminopropyltriethoxysilane (APTS), and then added to 90 g of anhydrous ethanol. The mixture was subjected to ultrasonic treatment at 100 W power and 25 °C for 15 min to form a homogenate. Then, the mixture was stirred at 78 °C for 4 hours. During the stirring process, 8 g of distilled water was slowly added to the above solution. Subsequently, the slurry was filtered and washed five times with anhydrous ethanol. Then, it was dried in an oven at 200 °C for 24 hours to remove residual APTS, water and ethanol, resulting in micro / nano diamond particles with surface silanization treatment.

[0059] Step 2: Dissolve 20 g of bisphenol A epoxy resin in 6 g of xylene, and add 2 g of polydimethylsiloxane. Then add 3.8 g of surface-silanized diamond powder with a particle size of 5 μm and 0.2 g of surface-silanized diamond powder with a particle size of 5 nm. Stir with a magnetic stirrer at 240 r / min for 30 minutes, then add 8 g of T31 curing agent and continue stirring for 20 minutes.

[0060] Step 3: Place the stirred suspension in a vacuum chamber at 5 Pa for 15 minutes to remove air bubbles; rinse the substrate surface with deionized water for 2 minutes to remove dust; spray with compressed air at 0.6 MPa for 5 seconds, and keep the distance between the sample and the spray gun at 15 cm. Step 4: After spraying, the sample is cured in a forced-air drying oven at 60 ℃ for 12 hours to obtain a micro-nano diamond-reinforced epoxy coating with a coating thickness of 20±2 μm.

[0061] Figure 2 The image shows the surface morphology of the micro / nano diamond-reinforced epoxy coating prepared in this embodiment. Figure 2 It can be seen that a non-smooth surface similar to the "dung beetle's head shell" has been formed on the surface to reduce adhesion and drag, and the overall color of the coating is darker at a wetting angle of 130°.

[0062] Example 2 The difference between this embodiment and Embodiment 1 is that: Step 1: Mix 0.5 g of micro / nano-sized diamond particles with an average particle size of 3 μm and 0.1 g of nano-sized diamond particles with an average particle size of 3 nm with 2 g of 3-aminopropyltrimethoxysilane, and then add them to 90 g of anhydrous ethanol. The remaining steps are the same as in Example 1.

[0063] Step 2: Dissolve 20 g of bisphenol F epoxy resin in 6 g of ethyl acetate, and add 2 g of polydimethylsiloxane. The remaining steps are the same as in Example 1.

[0064] Step 3 is the same as in Example 1.

[0065] Step four is the same as in Example 1. A micro / nano diamond-reinforced epoxy coating with a thickness of 20 ± 2 μm is obtained.

[0066] Example 3 The difference between this embodiment and Embodiment 1 is that: Step 1: Mix 0.5 g of micro / nano-sized diamond particles with an average particle size of 7 μm and 0.1 g of nano-sized diamond particles with an average particle size of 7 nm with 1 g of APTS, and then add them to 80 g of anhydrous ethanol. The remaining steps are the same as in Example 1.

[0067] Step 2: Dissolve 16 g of bisphenol A epoxy resin in 4 g of xylene, and add 1 g of polydimethylsiloxane. Then add 2 g of surface-silanized diamond powder with a particle size of 7 μm and 0.2 g of surface-silanized diamond powder with a particle size of 7 nm. Stir with a magnetic stirrer at 240 r / min for 30 minutes, then add 8 g of T31 curing agent and continue stirring for 20 minutes.

[0068] Step 3 is the same as in Example 1.

[0069] Step four is the same as in Example 1. A micro / nano diamond-reinforced epoxy coating with a thickness of 20 ± 2 μm is obtained.

[0070] Example 4 The difference between this embodiment and Embodiment 1 is that: Step 1: Mix 0.5 g of micro / nano-sized diamond particles with an average particle size of 7 μm and 0.1 g of nano-sized diamond particles with an average particle size of 7 nm with 3 g of APTS, and then add them to 90 g of anhydrous ethanol. The remaining steps are the same as in Example 1.

[0071] Step 2: Dissolve 30 g of bisphenol A epoxy resin in 8 g of xylene, and add 4 g of polydimethylsiloxane. Then add 5 g of surface-silanized diamond powder with a particle size of 7 μm and 0.2 g of surface-silanized diamond powder with a particle size of 7 nm. Stir with a magnetic stirrer at 240 r / min for 30 minutes, then add 8 g of T31 curing agent and continue stirring for 20 minutes.

[0072] Step 3 is the same as in Example 1.

[0073] Step four is the same as in Example 1. A micro / nano diamond-reinforced epoxy coating with a thickness of 20 ± 2 μm is obtained.

[0074] Comparative Example 1 This comparative example includes the following steps: Step 1: Dissolve 20 g of bisphenol A epoxy resin in 6 g of xylene, add 2 g of polydimethylsiloxane, stir with magnetic stirring at 240 r / min for 30 minutes, then add 8 g of T31 curing agent and continue stirring for 20 minutes.

[0075] Step 2: Place the stirred suspension in a vacuum chamber at 5 Pa for 15 minutes to remove air bubbles; rinse the substrate surface with deionized water for 2 minutes to remove dust; spray with compressed air at 0.6 MPa for 5 seconds, and keep the distance between the sample and the spray gun at 15 cm. Step 3: After spraying, the sample is cured in a forced-air drying oven at 60 ℃ for 12 hours to obtain an epoxy coating with a thickness of 20±2 μm.

[0076] Figure 3 The image shows the surface morphology of the epoxy coating prepared in this comparative example. Figure 3 It can be seen that the surface is smooth and contains some micron-sized pores.

[0077] Comparative Example 2 This comparative example includes the following steps: Step 1: Add 0.5 g of micron-sized diamond particles with an average particle size of 5 μm and 2 g of APTS to 90 g of anhydrous ethanol. Homogenize the mixture by ultrasonic treatment, and then stir at 78 °C for 4 hours. During the stirring process, slowly add 8 g of distilled water to the solution. Subsequently, filter the slurry and wash it five times with anhydrous ethanol. Then dry it in an oven at 200 °C for 24 hours to remove residual APTS, water and ethanol, and obtain micron-sized diamond particles with surface silanization treatment.

[0078] Step 2: Dissolve 20 g of bisphenol A epoxy resin in 6 g of xylene and add 2 g of polydimethylsiloxane. Then add 4 g of diamond micro powder with a particle size of 5 μm after surface silanization treatment, and stir with magnetic stirring at 240 r / min for 30 minutes. Then add 8 g of T31 curing agent and continue stirring for 20 minutes.

[0079] Step 3: Place the stirred suspension in a vacuum chamber at 5 Pa for 15 minutes to remove air bubbles; rinse the substrate surface with deionized water for 2 minutes to remove dust; spray with compressed air at 0.6 MPa for 5 seconds, and keep the distance between the sample and the spray gun at 15 cm. Step 4: After spraying, the sample is cured in a forced-air drying oven at 60 ℃ for 12 hours to obtain a micron diamond-reinforced epoxy coating with a coating thickness of 20±2 μm.

[0080] Figure 4 The image shows the surface morphology of the micron-sized diamond-reinforced epoxy coating prepared in this comparative example. Figure 4 It can be seen that a non-smooth surface similar to the "dung beetle's head shell" has been formed on the surface to reduce adhesion and drag, but the overall color is relatively light.

[0081] Comparative Example 3 This comparative example includes the following steps: Step 1: 0.1 g of nano-sized diamond particles with an average particle size of 5 nm and 2 g of APTS were added to 90 g of anhydrous ethanol. The mixture was homogenized by ultrasonic treatment and then stirred at 78 °C for 4 hours. During the stirring process, 8 g of distilled water was slowly added to the solution. The slurry was then filtered and washed five times with anhydrous ethanol. Finally, it was dried in an oven at 200 °C for 24 hours to remove residual APTS, water and ethanol, resulting in nano-sized diamond particles with surface silanization treatment.

[0082] Step 2: Dissolve 20 g of bisphenol A epoxy resin in 6 g of xylene and add 2 g of polydimethylsiloxane. Then add 4 g of surface-silanized diamond micro powder with a particle size of 5 nm, and stir with a magnetic stirrer at 240 r / min for 30 minutes. Then add 8 g of T31 curing agent and continue stirring for 20 minutes.

[0083] Step 3: Place the stirred suspension in a vacuum chamber at 5 Pa for 15 minutes to remove air bubbles; rinse the substrate surface with deionized water for 2 minutes to remove dust; spray with compressed air at 0.6 MPa for 5 seconds, and keep the distance between the sample and the spray gun at 15 cm. Step 4: After spraying, the sample is cured in a forced-air drying oven at 60 ℃ for 12 hours to obtain a nano-diamond reinforced epoxy coating with a coating thickness of 20±2 μm.

[0084] Comparative Example 4 This comparative example includes the following steps: Step 1: Dissolve 20 g of bisphenol A type epoxy resin in 6 g of xylene, and add 2 g of polydimethylsiloxane. Then add 3.8 g of untreated diamond powder with a particle size of 5 μm and 0.1 g of untreated diamond powder with a particle size of 5 nm. Stir with a magnetic stirrer at 240 r / min for 30 minutes, then add 8 g of T31 curing agent and continue stirring for 20 minutes.

[0085] Step 2: Place the stirred suspension in a vacuum chamber at 5 Pa for 15 minutes to remove air bubbles; rinse the substrate surface with deionized water for 2 minutes to remove dust; spray with compressed air at 0.6 MPa for 5 seconds, and keep the distance between the sample and the spray gun at 15 cm. Step 3: After spraying, the sample is cured in a forced-air drying oven at 60 ℃ for 12 hours to obtain a micro-nano diamond-reinforced epoxy coating with a coating thickness of 20±2 μm.

[0086] Performance testing The coatings prepared in some embodiments and comparative examples of this invention were tested for wear resistance, water resistance, and corrosion resistance. The specific test methods are as follows: (1) Wear resistance: The frictional properties of the coating were measured using a rotary ball-and-disc friction and wear tester. The diameter of the disc-shaped coating sample was 50 mm, and the thickness was approximately 3 mm. Bearing-grade steel balls with a diameter of 6.35 mm were used. An axial force F of 15 N was applied as pressure, and the friction test began after a preload of 15 seconds. The rotation radius r was 10 mm, the rotation speed n was 100 r / min, the linear velocity v was 6.28 m / min, and the duration t was 60 min. After the friction test, the wear tracks of the sample were characterized using a BD-40 metallographic microscope with a profilometer, and the wear volume V was obtained. The wear rate K was calculated using the following formula: (2) Water and corrosion resistance: According to GB / 1738-1979 "Determination of water absorption rate of insulating varnish film", weigh a 2 cm × 2 cm dry aluminum plate and record the mass as W0. Then spray an epoxy resin coating onto the aluminum plate, and weigh it after curing and record the mass as W1. Soak it in deionized water for 7 days, take it out, wipe the residual water on the surface with filter paper, and weigh it and record the mass as W2. Then calculate the water absorption rate of the epoxy coating using the following formula: Figure 5 This is a comparison chart of the wear amount of the coatings prepared in Example 1, Comparative Example 1 and Comparative Example 2 of the present invention.

[0087] like Figure 5 The wear rates of Comparative Example 1, Comparative Example 2, and Example 1 under dry sliding conditions with a load of 15 N are shown (the grinding balls are steel balls). The results show that the wear rate of Comparative Example 2 is 11.79 × 10⁻⁶. 5 mm 3 N 1 m 1 Comparison Example 1: Coating (33.58 × 10⁻⁶) 5 mm 3 N 1 m 1 The value was reduced by 64.9%. Example 1 further reduced it to 8.92 × 10⁻⁶. 5 mm 3 N 1 m 1Compared to a pure EP coating, the wear resistance was reduced by 73.4%. This result indicates that adding uniformly dispersed micro / nano diamond particles can significantly improve the wear resistance of epoxy resin coatings.

[0088] Figure 6 This is a comparison chart showing the water absorption rate of the coatings prepared in Example 1, Comparative Example 1, and Comparative Example 2 of this invention after immersion in a 3.5 wt.% sodium chloride solution for 168 hours. Figure 5 As shown, the epoxy resin coating with added surface-modified micro / nano diamond particles exhibited a significantly lower water absorption rate compared to the epoxy resin coating without added particles (Comparative Example 1). This is because the introduction of diamond particles eliminates the free volume of the epoxy resin coating, restricting the passage of electrolyte solution molecules. The water absorption rate in Comparative Example 1 was 6.91%, and in Comparative Example 2 it was 3.12%. Example 1, which incorporated both micron- and nano-sized diamond particles, showed a water absorption rate of only 2.03% after immersion for 168 hours, demonstrating extremely strong water resistance.

[0089] The coating obtained in Example 2 is a non-smooth surface that reduces viscosity and drag. The overall color of the coating is relatively dark, and the wear rate is 9.2 × 10⁻⁶. 5 mm 3 N 1 m 1 The water absorption rate after soaking for 168 hours was 2.4%.

[0090] The coating obtained in Example 3 is a non-smooth surface that reduces viscosity and drag. The overall color of the coating is relatively dark, and the wear rate is 9.6 × 10⁻⁶. 5 mm 3 N 1 m 1 The water absorption rate after soaking for 168 hours was 2.7%.

[0091] The coating obtained in Example 4 is a non-smooth surface that reduces viscosity and drag. The overall color of the coating is relatively dark, and the wear rate is 9.5 × 10⁻⁶. 5 mm 3 N 1 m 1 The water absorption rate after soaking for 168 hours is 3.0%.

[0092] The coating obtained in Comparative Example 3 had a smooth surface and a wear rate of 13.68 × 10⁻⁶. 5 mm 3 N 1 m 1 The water absorption rate after soaking for 168 hours was 2.41%.

[0093] The coating obtained in Comparative Example 4 exhibits a distinct particle aggregation morphology, accompanied by numerous micropores. The wear rate is 49.19 × 10⁻⁶. 5 mm 3 N 1 m 1 The water absorption rate after soaking for 168 hours was 10.74%.

[0094] In addition, the present invention has also conducted experiments with other raw materials, process operations and process conditions described in this specification, with reference to the foregoing embodiments, and has obtained relatively ideal results in all cases.

[0095] Although the invention has been described with reference to illustrative embodiments, those skilled in the art will understand that various other changes, omissions, and / or additions can be made without departing from the spirit and scope of the invention, and that elements of the embodiments can be substituted with substantially equivalents. Furthermore, many modifications can be made without departing from the scope of the invention to adapt particular situations or materials to the teachings of the invention. Therefore, this invention is not intended to be limited to the specific embodiments disclosed for carrying out the invention, but rather is intended to encompass all embodiments falling within the scope of the appended claims. Moreover, unless specifically stated otherwise, any use of the terms first, second, etc., does not indicate any order or importance, but is used to distinguish one element from another.

Claims

1. A method for preparing a micro / nano diamond-reinforced corrosion-resistant and wear-resistant coating, characterized in that, Includes: Surface functionalization of micron-sized and nano-sized diamond particles was performed using a silane coupling agent via hydrolysis reaction. Epoxy resin, surface-functionalized micron-sized diamond particles, surface-functionalized nano-sized diamond particles, organic solvent, activator and curing agent are mixed evenly, then coated on the substrate surface and cured to obtain a micro / nano diamond-reinforced corrosion-resistant and wear-resistant coating.

2. The preparation method according to claim 1, characterized in that, Specifically, the process includes: adding the micron-sized diamond particles and nano-sized diamond particles, along with a silane coupling agent, to an anhydrous alcohol solvent, followed by ultrasonic treatment to form a uniformly dispersed mixed system; then adding water to the mixed system and carrying out the hydrolysis reaction at 70-90°C for 3-5 hours to complete the surface functionalization treatment. And / or, the preparation method specifically includes: adding to the epoxy resin, dissolving the epoxy resin in an organic solvent, adding an activator, then adding surface-functionalized micron-sized diamond particles and surface-functionalized nano-sized diamond particles, magnetically stirring at a speed of 200~300 r / min for 25~35 min, then adding a curing agent and continuing to stir for 15~25 min to obtain a mixed slurry; And / or, the preparation method specifically includes: vacuum defoaming the mixed slurry, then spraying the vacuum defoamed mixed slurry onto the substrate surface, curing at 50~80 ℃ for 8~16 h, to obtain the micro-nano diamond-reinforced corrosion-resistant and wear-resistant coating.

3. The preparation method according to claim 2, characterized in that... The mass ratio of the micron-sized diamond particles, silane coupling agent, anhydrous alcohol solvent, and water is 0.5:1~3:80~90:5~10; The mass ratio of the nano-sized diamond particles, silane coupling agent, anhydrous alcohol solvent, and water is 0.1:1~3:80~90:5~10; And / or, the mass ratio of the epoxy resin, organic solvent, activator and curing agent is 8~15∶2~4∶0.5~2∶4; And / or, the mass ratio of the surface-functionalized micron-sized diamond particles, the surface-functionalized nano-sized diamond particles, and the epoxy resin is 2~5:0.1~0.5:8~15; And / or, the anhydrous alcohol solvent is anhydrous ethanol.

4. The preparation method according to claim 2, characterized in that, The vacuum defoaming process includes: maintaining the mixed slurry in a vacuum-sealed environment of 3-5 Pa for 10-20 minutes to remove air bubbles.

5. The preparation method according to claim 2, characterized in that, Specifically, the process includes: cleaning the surface of the substrate, using a spraying device with compressed air at 0.4~0.8 MPa for 3~6 seconds, with the distance between the substrate and the spraying device being 10~30 cm, and spraying the vacuum-defoamed mixed slurry onto the surface of the substrate.

6. The preparation method according to claim 1, characterized in that... The average particle size of the micron-sized diamond particles is 3~7 μm; And / or, the average particle size of the nanoscale diamond particles is 3~7 nm; And / or, the silane coupling agent includes at least one of 3-aminopropyltriethoxysilane and 3-aminopropyltrimethoxysilane; And / or, the epoxy resin includes at least one of bisphenol A type epoxy resin and bisphenol F type epoxy resin; And / or, the organic solvent includes at least one of xylene, ethyl acetate, and propylene glycol; And / or, the activator includes polydimethylsiloxane; And / or, the curing agent includes T31 curing agent.

7. The micro / nano diamond-reinforced corrosion-resistant and wear-resistant coating prepared by the method according to any one of claims 1-6, characterized in that... The micro-nano diamond-reinforced corrosion-resistant and wear-resistant coating has a non-smooth surface structure.

8. The nano-diamond-reinforced corrosion-resistant and wear-resistant coating according to claim 7, characterized in that... The thickness of the micro-nano diamond-reinforced corrosion-resistant and wear-resistant coating is 15~40 μm; And / or, the surface roughness of the micro / nano diamond-reinforced corrosion-resistant and wear-resistant coating is 2~8μm; And / or, the water absorption of the micro / nano diamond-reinforced corrosion-resistant and wear-resistant coating is less than 5%; And / or, the wear rate of the micro / nano diamond-reinforced corrosion-resistant and wear-resistant coating is 10 -4 mm 3 N 1 m 1 the following.

9. The application of the micro / nano diamond-reinforced corrosion-resistant and wear-resistant coating of claim 7 or 8 in the protection of a substrate surface, wherein the substrate includes at least a partial surface of a drilling, marine engineering, or mechanical transmission component.

10. A corrosion-resistant and wear-resistant device, characterized in that, Includes a substrate and a micro / nano diamond-reinforced corrosion-resistant and wear-resistant coating as described in claim 7 or 8, applied to the surface of the substrate.

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