A nanobase wear-resistant coating material

Abstract

The present application belongs to the technical field of wear-resistant coating, and particularly relates to a nano-based wear-resistant coating material. The present application aims to solve the problem of poor performance stability of the existing wear-resistant coating material under harsh working conditions. The nano-based wear-resistant coating material provided by the present application comprises a hybrid adhesion bottom layer, a gradient transition layer and a hybrid enhancement top layer. The hybrid adhesion bottom layer is obtained by solidification of a bottom layer slurry. The hybrid enhancement top layer is obtained by solidification of a top layer slurry. The gradient transition layer is obtained by co-solidification of the bottom layer slurry and the top layer slurry. The bottom layer slurry comprises epoxy resin, ethyl silicate and gamma-(2,3-epoxypropoxy) propyl trimethoxysilane. The top layer slurry comprises polyamide resin, hybrid filler and oil-loaded microcapsules. After UV light treatment and heat curing, the hybrid adhesion bottom layer, the gradient transition layer and the hybrid enhancement top layer obtain the nano-based wear-resistant coating material product. The coating product prepared by the present application can still maintain good wear resistance and low friction coefficient under harsh working conditions.

Description

Technical Field

[0001] This invention belongs to the field of wear-resistant coating technology, specifically relating to a nano-based wear-resistant coating material. Background Technology

[0002] In modern industry, the failure of mechanical parts due to friction and wear is one of the main causes of economic losses and safety hazards. In order to extend equipment life and improve operating efficiency, surface engineering technology, especially wear-resistant coatings, has emerged.

[0003] Traditional wear-resistant coating technologies mainly include electroplating, thermal spraying, chemical / physical vapor deposition, and high-performance polymer coatings. These various wear-resistant coating materials offer excellent properties such as high hardness and high-temperature resistance. With the rise of nanotechnology, polymer-based nanocomposite coatings have emerged as a revolutionary solution to address the interface problems and limited performance characteristics of traditional wear-resistant coatings. This technology disperses nanoscale fillers, such as hard ceramic particles and self-lubricating materials, within a polymer matrix like epoxy resin or polyamide, attempting to achieve a balance of performance at the molecular scale. While the introduction of nanofillers has indeed brought significant performance leaps, it has also introduced a series of new technical challenges. Nanoparticles, due to their extremely high specific surface area, are prone to aggregation, easily forming defects in the coating and leading to a decline in coating performance. Simultaneously, homogeneous single-layer coatings struggle to maintain performance stability under harsh operating conditions. In most cases, a physical interface with abrupt performance changes still exists between the coating and the metal substrate, and a single coating cannot simultaneously optimize conflicting properties. This means that while nanomaterials possess excellent properties, they are difficult to utilize effectively within a coating material system.

[0004] To address the problem of poor performance stability of existing wear-resistant coating materials under harsh working conditions, a nano-based wear-resistant coating material is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a nano-based wear-resistant coating material. The nano-based wear-resistant coating material comprises: a hybrid adhesion underlayer, a gradient transition layer, and a hybrid reinforcement top layer; the hybrid adhesion underlayer is obtained by curing the underlayer slurry; the hybrid reinforcement top layer is obtained by curing the top layer slurry; the gradient transition layer is obtained by co-spraying and curing the underlayer and top layer slurries. The underlayer slurry comprises: epoxy resin, tetraethyl orthosilicate, and γ-(2,3-epoxypropoxy)propyltrimethoxysilane; the top layer slurry comprises: polyamide resin, hybrid filler, and oil-loaded microcapsules. The hybrid adhesion underlayer, gradient transition layer, and hybrid reinforcement top layer are subjected to UV light treatment and thermosetting to obtain the nano-based wear-resistant coating material product.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A nano-based wear-resistant coating material includes: a hybrid adhesion underlayer, a gradient transition layer, and a hybrid reinforcement top layer.

[0007] The hybrid adhesion underlayer is obtained by curing the underlayer slurry, the gradient transition layer is obtained by spraying the underlayer slurry and the top layer slurry together and then curing, and the hybrid reinforcement top layer is obtained by curing the top layer slurry.

[0008] The target thickness of the hybrid attachment layer is 20-30 μm; the target thickness of the gradient transition layer is 30 μm; and the target thickness of the hybrid enhancement top layer is 30-45 μm.

[0009] The base slurry comprises: 100 parts bisphenol A type epoxy resin E51, 10 parts γ-(2,3-epoxypropoxy)propyltrimethoxysilane, 15-25 parts tetraethyl orthosilicate, 20 parts ethylene glycol butyl ether, 15 parts xylene, 1 part glacial acetic acid, and 4.5 parts deionized water. During the preparation of the base slurry, glacial acetic acid and deionized water are essential components for hydrolysis and polycondensation. They are added after the other components are mixed, heated to 60°C, stirred for 2 hours, and then cooled for later use. Before use, the prepared base slurry is mixed with 80 parts of a thermosetting agent, wherein the thermosetting agent is T31 epoxy resin curing agent. The average viscosity of epoxy resin E51 is 12000 mPa·s, and the average molecular weight is 400 g / mol; the active hydrogen equivalent of T31 epoxy resin curing agent is 75 g / eq, and the viscosity is 400 mPa·s.

[0010] The top layer slurry comprises: 100 parts polyamide resin PA11, 200 parts m-cresol, 5 parts hybrid filler, 3 parts oil-loaded microcapsules, 2 parts photoinitiator 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO), and 10 parts thermosetting agent, wherein the thermosetting agent is ε-caprolactam-terminated hexamethylene diisocyanate. The deblocking temperature range of the ε-caprolactam-terminated hexamethylene diisocyanate used in this invention is 160-180℃. The average molecular weight of polyamide resin PA11 is 20000 g / mol.

[0011] Before spraying, 10 parts of polyurethane acrylate oligomer with an average molecular weight of 2000 g / mol, an acrylate functionality of 2, a hydroxyl value of 55 mg KOH / g, and a viscosity of 12000 mPa·s are added to the top coat slurry. As the main photocurable component, it can rapidly crosslink and cure during subsequent UV light treatment, and undergo sufficient copolymerization with other components during the thermosetting stage.

[0012] The hybrid filler is prepared by the following method: silicon carbide nanoparticles with an average particle size of 50 nm are heated to 900-1000 °C in a mixed atmosphere of argon / hydrogen, wherein the flow rate of argon is 100 sccm and the flow rate of hydrogen is 20 sccm; methane is introduced and reacted for 30 min, wherein the flow rate of methane is 5 sccm. After the reaction is completed, a filler precursor with a core-shell structure is obtained. Ten parts of the filler precursor were dispersed in anhydrous ethanol and ultrasonically treated. Then, one part of γ-aminopropyltriethoxysilane and 0.5 parts of deionized water were added dropwise. The mixture was refluxed and stirred at 75°C for 4 hours. After washing and drying, the resulting solid product was obtained as the hybrid filler. The surface shell of the hybrid filler obtained by this method is a silane-modified graphene nanosheet structure, and the core layer is silicon carbide.

[0013] The silicon carbide nanoparticles used in this invention have a β-silicon carbide crystal form.

[0014] The oil-loaded microcapsules were prepared by the following method: 30 parts of perfluoropolyether glycol and 5 parts of toluene diisocyanate were mixed to obtain an oil phase; 1 part of polyvinyl alcohol was dissolved in 100 parts of deionized water to obtain an aqueous phase; the oil phase was slowly added dropwise to the aqueous phase to form an emulsion, which was then heated to 60°C and stirred at a stirring rate of 8000 rpm. 3 parts of triethylamine were added dropwise and dispersed for 10 min. The mixture was then reacted at 2000 rpm for 3 hours, filtered, washed, and dried to obtain the oil-loaded microcapsules. The average molecular weight of the perfluoropolyether glycol was 2000-3000 g / mol. The oil-loaded microcapsules obtained by this method had a polyurea shell and perfluoropolyether glycol contents, with an average particle size of 10-20 μm. The degree of alcoholysis of the polyvinyl alcohol was 88%, and the average degree of polymerization was 1700. The toluene diisocyanate contained 80% of the 2,4-isomer and 20% of the 2,6-isomer. The perfluoropolyether glycol has an average molecular weight of 2000 g / mol and is a lubricant product obtained by anionic polymerization.

[0015] The hybrid adhesion underlayer is obtained by the following process: after cleaning and sandblasting the steel surface, the spraying distance is set to 25cm, and the underlayer slurry is sprayed onto the steel surface at a spraying pressure of 0.4-0.6MPa until the target thickness is achieved.

[0016] The gradient transition layer is obtained through the following process: A hybrid substrate is sprayed onto its surface using two spray channels, one for the base coat and the other for the top coat. The component ratios are continuously varied during spraying. The spraying distance is 25 cm, and the spraying pressure is 0.4 MPa. Initially, 100% base coat is used, and the proportion of the top coat is linearly increased until the target thickness is reached, at which point the top coat is 100% complete.

[0017] The hybrid-enhanced top layer is obtained by the following process: the spraying distance is 25cm, the spraying pressure is 0.5MPa, and the top layer slurry is sprayed on the surface of the gradient transition layer until the target thickness is achieved.

[0018] After spraying, UV light treatment is performed using a high-pressure mercury lamp with an emission peak of 380nm and a light intensity of 80mW / cm². 2 The irradiation time is 15s, which induces rapid cross-linking in the shallow slurry and forms a pre-cured state. Then, a heat curing treatment is carried out, specifically: after holding at 80℃ for 60min, the temperature is raised to 170℃, held for 120min, and then cooled. The resulting complete coating is the nano-based wear-resistant coating material.

[0019] Unless otherwise specified, the parts in this invention refer to parts by mass.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: An interpenetrating polymer network structure is formed at the bottom of the coating using a base slurry, creating a hybrid adhesion substrate. Epoxy resin, a silane coupling agent, and tetraethyl orthosilicate are co-dissolved. Under the action of a catalyst, tetraethyl orthosilicate undergoes hydrolysis and condensation, forming a siloxane network. Simultaneously, the epoxy end groups of the silane coupling agent react with the curing agent of the epoxy resin, while the silanol end groups co-condense with the hydrolysis products of tetraethyl orthosilicate. The inorganic siloxane network provides extremely high hardness and load-bearing capacity, while the epoxy network ensures excellent adhesion to the substrate. The silane coupling agent acts as a molecular bridge, firmly connecting these two inherently incompatible networks through covalent bonds. The resulting hybrid adhesion substrate is essentially a uniformly interwoven organic-inorganic hybrid at the molecular level. It combines the hardness of ceramics with the adhesiveness of polymers, providing a good adhesion foundation for the upper coating.

[0021] By introducing hybrid fillers into the polyamide matrix to construct a hybrid reinforced top layer, a synergistic reinforced structure of hard core-soft shell-strong interface is formed. The silicon carbide nanoparticles in the hybrid filler provide a load-bearing effect, while its graphene shell is easily peeled off during friction to form a low-shear-strength transfer film, significantly reducing the coefficient of friction of the coating itself. The coupling agent firmly anchors the filler to the tough polyamide matrix, preventing premature detachment under shear force. In this way, the hard load-bearing function of silicon carbide and the solid lubrication function of graphene are integrated into the same nanostructure, combined with a specific composition of the tough polyamide matrix, ensuring both a low coefficient of friction and good wear resistance.

[0022] By employing a gradient spraying process, a gradient transition layer is formed between the hybrid-attached underlayer and the hybrid-reinforced toplayer. Two spray channels are used to load the underlayer and toplayer slurries respectively. During spraying, the component ratios are continuously adjusted to ensure that the coating composition of the gradient transition layer gradually transitions from 100% underlayer slurry (near the hybrid-attached underlayer) to 100% toplayer slurry. This structure allows for a smooth transition in the coating's elastic modulus and hardness from the underlayer to the toplayer, effectively dispersing external loads and thermal stresses, ensuring the structural integrity of the entire coating system, and guaranteeing the long-term stability of the coated material under harsh operating conditions.

[0023] Oil-loaded microcapsules were prepared by in-situ polymerization and introduced into the top-layer slurry, introducing self-lubricating properties to the hybrid-reinforced top layer. Upon severe scratching or impact, stress concentration caused the brittle oil-loaded microcapsules to rupture, releasing a highly lubricating perfluoropolyether glycol lubricant. The liquid lubricant spreads rapidly, providing emergency lubrication in the damaged area, preventing localized severe friction and protecting the coating itself. This liquid-solid dual lubrication mechanism gives the coating both long-lasting and emergency-response properties, significantly improving the service reliability of the coating material.

[0024] Based on specific base and top coat formulations, different photoinitiators and thermosetting agents are introduced into each type of coating. After spraying, low-energy UV light irradiation is applied to induce rapid cross-linking within the shallow layers of the coating, forming a pre-cured state. Subsequent thermosetting ensures complete curing of the coating. In the base coat, only a thermosetting agent is introduced, while in the top coat, both a photoinitiator and a thermosetting agent are introduced. This allows the coating to rapidly cure its internal gradient structure and filler dispersion under UV light after spraying, preventing component sedimentation or flow during subsequent processing. The hybrid substrate is less affected by UV light, allowing subsequent thermosetting to further solidify and shape the substrate structure, achieving deep cross-linking and overall curing of the coating material. This combination of different curing methods ensures the self-lubricating properties of the coating material and optimizes interlayer adhesion, further enhancing its performance stability under harsh conditions. Attached Figure Description

[0025] Figure 1 This is a process flow diagram for preparing the nano-based wear-resistant coating material in this invention. Detailed Implementation

[0026] The technical solution of the present invention will be clearly and completely described below through some embodiments and experimental examples. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0027] Reference Figure 1 The process flow diagram shown illustrates that this invention provides a nano-based wear-resistant coating material, with the technical solution as follows: Example

[0028] A nano-based wear-resistant coating material includes: a hybrid adhesion underlayer, a gradient transition layer, and a hybrid reinforcement top layer.

[0029] The hybrid adhesion underlayer is obtained by curing the underlayer slurry, the gradient transition layer is obtained by spraying the underlayer slurry and the top layer slurry together and then curing, and the hybrid reinforcement top layer is obtained by curing the top layer slurry.

[0030] The target thickness of the hybrid attachment layer is 20 μm; the target thickness of the gradient transition layer is 30 μm; and the target thickness of the hybrid enhancement top layer is 30 μm.

[0031] The base coat consists of: 100 parts bisphenol A type epoxy resin E51, 10 parts γ-(2,3-epoxypropoxy)propyltrimethoxysilane, 15 parts tetraethyl orthosilicate, 20 parts ethylene glycol butyl ether, 15 parts xylene, 1 part glacial acetic acid, and 4.5 parts deionized water. During the preparation of the base coat, glacial acetic acid and deionized water are essential components for hydrolysis and polycondensation. They are added after the other components are mixed, and the mixture is heated to 60°C, stirred for 2 hours, and then cooled for later use. Before use, the prepared base coat is mixed with 80 parts of a thermosetting agent, wherein the thermosetting agent is T31 epoxy resin curing agent.

[0032] The top coat slurry comprises: 100 parts polyamide resin PA11, 200 parts m-cresol, 5 parts hybrid filler, 3 parts oil-loaded microcapsules, 2 parts photoinitiator 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO), and 10 parts thermosetting agent, wherein the thermosetting agent is ε-caprolactam-terminated hexamethylene diisocyanate. Before spraying, 10 parts of polyurethane acrylate oligomer with an average molecular weight of 2000 g / mol, an acrylate functionality of 2, a hydroxyl value of 55 mg KOH / g, and a viscosity of 12000 mPa·s are added to the top coat slurry.

[0033] The hybrid filler was prepared by the following method: silicon carbide nanoparticles with an average particle size of 50 nm were heated to 900 °C in a mixed atmosphere of argon / hydrogen, wherein the flow rate of argon was 100 sccm and the flow rate of hydrogen was 20 sccm; methane was introduced and reacted for 30 min, wherein the flow rate of methane was 5 sccm. After the reaction was completed, a filler precursor with a core-shell structure was obtained. Ten parts of the filler precursor were dispersed in anhydrous ethanol and ultrasonically treated. Then, 1 part of γ-aminopropyltriethoxysilane and 0.5 parts of deionized water were added dropwise. After refluxing and stirring at 75°C for 4 hours, the solid product was washed and dried to obtain the hybrid filler.

[0034] The oil-loaded microcapsules were prepared by the following method: 30 parts of perfluoropolyether glycol and 5 parts of toluene diisocyanate were mixed to obtain an oil phase; 1 part of polyvinyl alcohol was dissolved in 100 parts of deionized water to obtain an aqueous phase; the oil phase was slowly added dropwise to the aqueous phase to form an emulsion, and then the temperature was raised to 60°C for stirring at a stirring rate of 8000 rpm. After adding 3 parts of triethylamine and dispersing for 10 min, the mixture was reacted at a speed of 2000 rpm for 3 hours, and then filtered, washed, and dried to obtain the oil-loaded microcapsules.

[0035] The hybrid adhesion underlayer is obtained by the following process: after cleaning and sandblasting the steel surface, the spraying distance is set to 25cm, and the underlayer slurry is sprayed onto the steel surface at a spraying pressure of 0.4MPa until the target thickness is achieved.

[0036] The gradient transition layer is obtained through the following process: A hybrid substrate is sprayed onto its surface using two spray channels, one for the base coat and the other for the top coat. The component ratios are continuously varied during spraying. The spraying distance is 25 cm, and the spraying pressure is 0.4 MPa. Initially, 100% base coat is used, and the proportion of the top coat is linearly increased until the target thickness is reached, at which point the top coat is 100% complete.

[0037] The hybrid-enhanced top layer is obtained by the following process: the spraying distance is 25cm, the spraying pressure is 0.5MPa, and the top layer slurry is sprayed on the surface of the gradient transition layer until the target thickness is achieved.

[0038] After spraying, UV light treatment is performed using a high-pressure mercury lamp with an emission peak of 380nm and a light intensity of 80mW / cm². 2 The irradiation time is 15s, which induces rapid cross-linking in the shallow slurry and forms a pre-cured state. Then, a heat curing treatment is carried out, specifically: after holding at 80℃ for 60min, the temperature is raised to 170℃, held for 120min, and then cooled. The resulting complete coating is the nano-based wear-resistant coating material.

[0039] Examples 2-18 differ from Example 1 in operating parameters, but the other process steps and the range of raw material selection are the same.

[0040] The specific changes in operating parameters are summarized in Table 1.

[0041] Table 1. Changes in operating parameters in Examples 1-18 Example 1 20 30 15 900 0.4 Example 2 30 45 25 1000 0.6 Example 3 23 35 18 930 0.5 Example 4 28 40 21 975 0.4 Example 5 21 32 16 910 0.6 Example 6 26 44 24 990 0.5 Example 7 29 38 17 925 0.6 Example 8 22 31 20 960 0.4 Example 9 27 42 22 945 0.5 Example 10 24 36 15 905 0.6 Example 11 30 45 25 1000 0.4 Example 12 20 30 15 900 0.5 Example 13 25 39 23 985 0.6 Example 14 23 41 19 915 0.4 Example 15 28 33 16 935 0.5 Example 16 21 43 21 965 0.6 Example 17 26 37 18 955 0.4 Example 18 29 34 24 920 0.5 Comparative Example 1 Unlike Example 1, tetraethyl orthosilicate was not added; instead, 10 parts of nano-silica were used, wherein the average particle size of the nano-silica was 50 nm, and all other process parameters were the same.

[0042] Comparative Example 2 Unlike Example 1, tetraethyl orthosilicate was not added, but all other process parameters remained the same.

[0043] Comparative Example 3 Unlike Example 5, no hybrid filler was added, but all other process parameters remained the same.

[0044] Comparative Example 4 Unlike Example 5, this example uses 1 part graphene nanosheets and 4 parts silicon carbide nanoparticles instead of hybrid fillers, while all other process parameters remain the same.

[0045] Comparative Example 5 Unlike Example 5, methane gas was not introduced into the hybrid filler to generate a graphene shell on its surface during the preparation of the hybrid filler, while all other process parameters remained the same.

[0046] Comparative Example 6 Unlike Example 9, no gradient transition layer is set, but all other process parameters are the same.

[0047] Comparative Example 7 Unlike Example 9, the gradient transition layer is entirely sprayed with a mixture of 50% bottom layer slurry and 50% top layer slurry, without any linear adjustment of the component ratio, and all other process parameters are the same.

[0048] Comparative Example 8 Unlike Example 13, no oil-carrying microcapsules were added, but all other process parameters remained the same.

[0049] Comparative Example 9 Unlike Example 13, an equal number of oil-carrying microcapsules were also added to the bottom slurry, while other process parameters remained the same.

[0050] Comparative Example 10 Unlike Example 16, UV light treatment was not performed; instead, thermosetting was carried out directly, while all other process parameters remained the same.

[0051] Comparative Example 11 Unlike Example 16, the final temperature for thermosetting was adjusted to 200°C, while all other process parameters remained the same.

[0052] Comparative Example 12 Unlike Example 16, two additional parts of photoinitiator TPO were added to the bottom slurry, while all other process parameters remained the same.

[0053] Experimental Example 1 The coating adhesion and interface hardness of the nano-based wear-resistant coating materials prepared in Examples 1-4 and Comparative Examples 1-2 were tested, and the relevant results are summarized in Table 2.

[0054] The coating adhesion test method is as follows: refer to the relevant test method of ASTM D3359 standard, measure the coating adhesion of the individual hybrid adhesion substrate, use the cross-cut test, and record the peeling situation (0B-5B). The hybrid adhesion substrate is cured by single-stage heat curing.

[0055] The method for testing interface hardness is as follows: perform indentation test on the interface of a single hybrid adhesion substrate, record its hardness and elastic modulus, and calculate its nanoindentation hardness (GPa).

[0056] Table 2. Coating adhesion and interfacial hardness of the nano-based wear-resistant coating materials prepared in Examples 1-4 and Comparative Examples 1-2. Example 1 5B 1.8 Example 2 5B 1.8 Example 3 5B 1.7 Example 4 5B 1.8 Comparative Example 1 4B 1.3 Comparative Example 2 3B 0.6 As shown in Table 2, the coating adhesion grade and nanoindentation hardness of Examples 1-4 are significantly better than those of Comparative Example 1 and Comparative Example 2, indicating that the hybrid adhesion substrates prepared in the examples have obvious advantages in terms of adhesion and hardness.

[0057] Comparative Example 2, without the addition of tetraethyl orthosilicate, relied solely on the adhesive properties of the epoxy resin itself, resulting in the lowest coating adhesion grade and the lack of inorganic network reinforcement, leading to the worst nanoindentation hardness. Comparative Example 1 used nano-silica instead of tetraethyl orthosilicate; this physical blending method makes it difficult to form a uniform and dense network structure at the molecular level. The nanoparticles easily aggregated, and their interfacial bonding with the resin was weaker than the in-situ formed chemical bonds, resulting in a significant decrease in both hardness and coating adhesion.

[0058] In summary, this invention co-dissolves epoxy resin, tetraethyl orthosilicate, and a silane coupling agent. Tetraethyl orthosilicate undergoes in-situ hydrolysis and condensation under the action of a catalyst, forming a high-hardness inorganic silicon-oxygen bond network. Simultaneously, the silane coupling agent acts as a molecular bridge, reacting with the epoxy resin at one end and co-condensing with the hydrolysis products of tetraethyl orthosilicate at the other end, firmly connecting the organic and inorganic networks through covalent bonds. These two components produce a significant synergistic effect, forming a uniformly interwoven organic-inorganic hybrid at the molecular level, achieving a balance between adhesion and hardness, and significantly improving the coating's adhesion and load-bearing capacity.

[0059] Experimental Example 2 The wear resistance and coefficient of friction of the nano-based wear-resistant coating materials prepared in Examples 5-8 and Comparative Examples 3-5 were tested, and the relevant results are summarized in Table 3.

[0060] The test methods for wear resistance and coefficient of friction are as follows: referring to the relevant test methods in ASTM G99, using AISI 52100 steel balls as the friction pair, the surface coefficient of friction and wear rate (10 N) of the coated material sample are measured under a load of 10 N. -6 mm 3 / N·m). The lower the wear rate, the better the wear resistance.

[0061] Table 3. Wear resistance and coefficient of friction of the nano-based wear-resistant coating materials prepared in Examples 5-8 and Comparative Examples 3-5. Example 5 0.12 1.5 Example 6 0.12 1.8 Example 7 0.11 1.7 Example 8 0.13 1.5 Comparative Example 3 0.45 118.4 Comparative Example 4 0.28 77.8 Comparative Example 5 0.40 23.1 As shown in Table 3, the friction coefficients and wear rates of Examples 5-8 are significantly better than those of Comparative Examples 3, 4 and 5, indicating that the hybrid reinforced top layer prepared in the examples has obvious advantages in reducing friction and improving wear resistance.

[0062] Comparative Example 3, without the addition of hybrid fillers (i.e., a pure polyamide matrix), exhibited the highest coefficient of friction and the worst wear rate, demonstrating the necessity of functional fillers. Comparative Example 5, which did not introduce methane gas during filler preparation and lacked a graphene shell, showed improved wear resistance due to the load-bearing effect of silicon carbide particles, but its coefficient of friction remained very high. Comparative Example 4 used a physical blend of graphene and silicon carbide without a modified binder, resulting in weak interfacial bonding between the filler and the matrix. Although the coefficient of friction was reduced, the hard silicon carbide particles were easily detached under shear force, causing severe abrasive wear and resulting in a very high wear rate.

[0063] In summary, this invention constructs a hybrid reinforced top layer by introducing hybrid fillers into a polyamide matrix. The silicon carbide nanoparticles in the hybrid filler provide a load-bearing effect, while its graphene shell forms a low-shear-strength transfer film during friction, significantly reducing the coefficient of friction. The coupling agent firmly anchors the filler within the robust polyamide matrix, preventing premature detachment. This synergistic effect of a hard-core load-bearing function, a soft-shell lubrication function, and strong interfacial anchoring, combined with the robust polyamide matrix, optimizes performance, significantly improving the coating's wear resistance while maintaining a low coefficient of friction.

[0064] Experimental Example 3 The thermal cycling stability and interlayer adhesion of the nano-based wear-resistant coating materials prepared in Examples 9-12 and Comparative Examples 6-7 were tested. The relevant results are summarized in Table 4.

[0065] The test method for thermal cycling stability is as follows: the sample coating material product is subjected to 100 cycles of hot and cold cycling in the temperature range of -40℃ to 170℃, with each cycle lasting 4 hours. After completion, the coating product is recorded to see if blistering, cracking or peeling occurs.

[0066] The test method for interlayer adhesion is as follows: For samples that have undergone thermal cycling tests, refer to the relevant test methods of ASTM C1624 standard, and use a scratch tester to test the critical load Lc (N) of the coating material. The larger Lc is, the smaller the tendency for interlayer delamination to occur inside the coating material.

[0067] Table 4. Thermal cycling stability and interlayer adhesion of the nano-based wear-resistant coating materials prepared in Examples 9-12 and Comparative Examples 6-7 Example 9 No bubbles, no cracks, no peeling 65 Example 10 No bubbles, no cracks, no peeling 67 Example 11 No bubbles, no cracks, no peeling 65 Example 12 No bubbles, no cracks, no peeling 66 Comparative Example 6 Edge cracking, interlayer delamination 30 Comparative Example 7 Microcracks and edge blistering appeared 44 As shown in Table 4, no abnormalities were observed in Examples 9-12 after the thermal cycling test, and their critical load Lc values ​​were significantly higher than those of Comparative Examples 6 and 7, indicating that the gradient transition layer structure used in the examples has significant advantages in improving the structural integrity and long-term stability of the coating system.

[0068] Comparative Example 6, lacking a gradient transition layer, creates an abrupt interface of physical properties between the high-hardness hybrid substrate and the high-toughness hybrid reinforced top layer. During thermal cycling, thermal stress is highly concentrated at this interface, ultimately leading to cracking and delamination, and the interlayer bonding strength is also the worst. Comparative Example 7 uses a homogeneous blend layer, which still creates two interfaces with abrupt performance changes. The stress dispersion effect is far inferior to the continuous gradient structure of the examples, therefore its stability and critical load are both inferior to those of the examples.

[0069] In summary, this invention employs a gradient spraying process, using two spray channels to load the bottom and top layers of slurry respectively. During the spraying process, the component ratios are continuously adjusted to allow the coating composition to gradually transition from the bottom layer to the top layer. This structural design and the synergistic effect of the spraying process enable a smooth transition in the coating's elastic modulus and hardness, fundamentally eliminating stress concentration between layers, effectively dispersing thermal stress, and significantly improving the structural integrity and long-term stability of the coating system.

[0070] Experiment Example 4 The friction coefficients and coating states of the nano-based wear-resistant coating materials prepared in Examples 13-16 and Comparative Examples 8-9 under sudden loads were tested, and the relevant results are summarized in Table 5.

[0071] The test method for sudden load is as follows: referring to the relevant test method of ASTM G99 standard, using AISI 52100 steel balls as friction pairs, running for 10 minutes under a friction load of 5N and recording the friction coefficient, then rapidly increasing the load to 30N, recording the instantaneous peak friction coefficient and the state of the coating after the load increase.

[0072] Table 5. Friction loads and coating states of the nano-based wear-resistant coatings prepared in Examples 13-16 and Comparative Examples 8-9 Example 13 0.14 0.08 Minor scratches Example 14 0.15 0.08 Minor scratches Example 15 0.14 0.09 Minor scratches Example 16 0.14 0.08 Minor scratches Comparative Example 8 0.16 0.42 Severe scratches Comparative Example 9 0.15 0.08 Minor scratches As shown in Table 5, the coefficients of friction of Examples 13-16 were significantly lower than those of Comparative Example 8 when the load suddenly increased to 30N, and the coatings remained intact, while Comparative Example 8 showed severe scratches. This indicates that the coatings of the Examples have significant advantages in dealing with sudden load changes and providing emergency protection.

[0073] Comparative Example 8, without the addition of oil-carrying microcapsules, exhibited a friction coefficient similar to that of the Example under a low load of 5N, both relying on solid lubrication from the hybrid filler. However, when the load suddenly increased to 30N, the solid lubrication failed, lacking an emergency lubrication mechanism, leading to a sharp increase in the friction coefficient and severe damage to the coating. Comparative Example 9, although containing microcapsules in the bottom slurry, had the same top slurry as the Example. Therefore, when only surface friction properties were tested, it exhibited the same excellent performance as the Example, further demonstrating the crucial role of the microcapsules in the top layer.

[0074] In summary, this invention synergizes with the solid lubrication provided by the hybrid filler by introducing in-situ polymerized oil-carrying microcapsules into the top slurry. When severe scratching or impact occurs, the brittle oil-carrying microcapsules rupture and release a highly lubricating perfluoropolyether glycol lubricant, providing emergency liquid lubrication in the damaged area. This effectively suppresses the dramatic increase in the coefficient of friction and protects the coating. This liquid-solid dual lubrication mechanism greatly improves the service reliability of the coating material.

[0075] Experimental Example 5 The friction coefficient and adhesion of the nano-based wear-resistant coating materials prepared in Examples 17-18 and Comparative Examples 10-12 under sudden load were tested, and the results are summarized in Table 6. Comparative Example 9 was also included for comparative testing within the same group.

[0076] The method for testing the coefficient of friction under abrupt load is the same as in Experiment Example 4, and the method for testing the coating adhesion is the same as in Experiment Example 1, but the test object is changed to a complete coating material.

[0077] Table 6. Friction load and coating adhesion of the nano-based wear-resistant coating materials prepared in Examples 17-18 and Comparative Examples 10-12 Example 17 0.15 0.09 5B Example 18 0.14 0.08 5B Comparative Example 10 0.35 0.42 5B Comparative Example 11 0.15 0.44 5B Comparative Example 12 0.14 0.09 2B Comparative Example 9 0.15 0.08 3B As shown in Table 6, Examples 17-18 exhibited excellent overall performance in terms of friction coefficient and coating adhesion grade under sudden load, while Comparative Examples 9, 10, 11 and 12 showed significant defects in friction performance or adhesion. This indicates that the composite curing process and slurry formulation used in the examples have significant advantages in ensuring the overall performance of the coating.

[0078] Comparative Example 10, without UV light treatment, experienced sedimentation of the gradient structure and functional fillers during the initial stage of thermosetting, leading to a loss of lubrication function on the coating surface and a significant increase in the coefficient of friction. Comparative Example 11 used an excessively high thermosetting temperature, causing the oil-carrying microcapsules to fail prematurely during curing, losing their emergency lubrication capability and resulting in a sharp increase in the coefficient of friction under high loads. Comparative Example 12 added a photoinitiator to the bottom slurry; however, UV light could not effectively penetrate to the bottom layer and accelerate its curing, while the photoinitiator component severely affected the chemical stability of the bottom slurry, reducing its original adhesion and resulting in the worst coating adhesion grade. Comparative Example 9 introduced microcapsules into the bottom layer, disrupting the structural integrity of the adhesion layer and causing a severe decrease in coating adhesion. In other words, in the technical solution of this invention, photoinitiators and microcapsules, as core components for UV light treatment and reducing surface friction, should be more concentrated in the surface layer, while minimizing their entry into the hybrid adhesion layer. The technical solution of this invention successfully solves this problem through the component design of the bottom and top slurries and the process control of mixed spraying.

[0079] In summary, this invention introduces both a photoinitiator and a thermosetting agent into the top layer slurry, while introducing only the thermosetting agent into the bottom layer slurry. After spraying, UV light treatment is first applied to rapidly cure the top layer and gradient transition layer, locking in the dispersion state and gradient structure of the functional fillers. The bottom layer slurry is less affected by ultraviolet light, and the subsequent medium-low temperature thermosetting process, without damaging the self-lubricating components of the top layer, enables deep cross-linking of the bottom layer slurry and the entire coating body. This synergistic effect of slurry design and curing process ensures the coating's self-lubricating properties and optimizes the interlayer adhesion, achieving overall curing and shaping of the coating material.

[0080] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A nano-based wear-resistant coating material, characterized in that: The nano-based wear-resistant coating material comprises: a hybrid adhesion underlayer, a gradient transition layer, and a hybrid reinforcement top layer; The hybrid adhesion substrate is obtained by curing the substrate slurry; the hybrid reinforcement top layer is obtained by curing the top layer slurry. The gradient transition layer is obtained by spraying and curing the bottom layer slurry and the top layer slurry together; The underlying slurry comprises 100 parts of bisphenol A type epoxy resin E51, 10 parts of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, 15 parts of tetraethyl orthosilicate, 20 parts of ethylene glycol butyl ether, 15 parts of xylene, 1 part of glacial acetic acid, and 4.5 parts of deionized water. During the preparation of the underlying slurry, glacial acetic acid and deionized water are essential components for hydrolysis and polycondensation. They are added after the other components are mixed, heated to 60°C, stirred for 2 hours, and then cooled for later use. Before use, the prepared underlying slurry is mixed with 80 parts of a thermosetting agent, wherein the thermosetting agent is T31 epoxy resin curing agent. The top layer slurry comprises 100 parts polyamide resin PA11, 200 parts m-cresol, 5 parts hybrid filler, 3 parts oil-loaded microcapsules, 2 parts photoinitiator 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO), and 10 parts thermosetting agent, wherein the thermosetting agent is ε-caprolactam-terminated hexamethylene diisocyanate; before spraying, 10 parts polyurethane acrylate oligomer with an average molecular weight of 2000 g / mol, an acrylate functionality of 2, a hydroxyl value of 55 mg KOH / g, and a viscosity of 12000 mPa·s is added to the top layer slurry; The hybrid filler is obtained by the following preparation method: silicon carbide nanoparticles are heated in a mixed atmosphere of argon and hydrogen, and then reacted with methane to obtain a filler precursor; the filler precursor is dispersed in anhydrous ethanol, and then reacted with γ-aminopropyltriethoxysilane to obtain the hybrid filler. The oil-loaded microcapsules are prepared by the following method: mixing perfluoropolyether glycol and toluene diisocyanate to obtain an oil phase; dissolving polyvinyl alcohol in deionized water to obtain an aqueous phase; adding the oil phase dropwise to the aqueous phase, heating and reacting, and adding triethylamine; washing and drying to obtain the oil-loaded microcapsules. The hybrid adhesion bottom layer, the gradient transition layer, and the hybrid reinforcement top layer are treated with UV light and then thermo-cured to obtain the nano-based wear-resistant coating material. The thermo-curing process is as follows: after holding at 80°C for 60 minutes, the temperature is raised to 170°C, held for 120 minutes, and then cooled. The resulting complete coating is the nano-based wear-resistant coating material. During the spraying process of the gradient transition layer, the bottom layer slurry and the top layer slurry are loaded into two spraying channels respectively. At the beginning of the spraying, 100% of the bottom layer slurry is used. During the spraying process, the proportion of the top layer slurry is linearly increased. At the end of the spraying, the proportion of the top layer slurry is 100%.

2. A nanomatrix wear resistant coating material according to claim 1, wherein: The UV light treatment process involves irradiating the hybrid attachment layer, the gradient transition layer, and the hybrid enhancement top layer with a high-pressure mercury lamp.

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