A method for coating a molybdenum disulfide protective layer on the surface of a titanium aviation fastener

Abstract

The present application relates to the field of metal protection technology and specifically discloses a method for coating a titanium aviation fastener with a molybdenum disulfide protective layer, comprising the following steps: S1. Fastener surface treatment: polishing the fastener surface to obtain a fastener with a surface roughness of 0.05-0.07 microns, cleaning it with an organic solvent, and then using a pulsed laser beam to form a honeycomb micropore array on the material surface with a pore size of 5-10 μm and a depth of 20-50 μm, thereby obtaining a pre-treated fastener; S2. Molybdenum disulfide coating: applying the molybdenum disulfide coating to the pre-treated fastener surface, storing it at room temperature for 12 hours, and then coating it with a hydrophobic protective layer; S3. Room temperature curing: curing the fastener coated with the hydrophobic protective layer at room temperature for 4-6 hours to obtain. The method of the present application can be used for surface protection of titanium aviation fasteners and has the advantages of good wear resistance and corrosion resistance.

Description

Technical Field

[0001] The present application relates to the field of metal protection technology, and more specifically, to a method for coating a molybdenum disulfide protective layer on the surface of a titanium aviation fastener. Background Art

[0002] In the aerospace industry, titanium and its alloys are widely used in the manufacture of various critical components, especially fasteners, due to their excellent strength-to-weight ratio, outstanding corrosion resistance, and biocompatibility. However, titanium aerospace fasteners face multiple challenges in actual use, mainly due to their specific service environments and application requirements.

[0003] First, while titanium alloys offer high mechanical strength, they have a relatively low surface hardness, making them susceptible to wear in applications involving high loads and frequent movement. Especially in high-temperature environments, titanium alloys' wear resistance decreases significantly, increasing the risk of component failure. Therefore, effectively reducing the coefficient of friction and improving the wear resistance of titanium aviation fasteners have become key challenges that need to be addressed.

[0004] Secondly, although titanium alloys inherently possess good corrosion resistance, they can still suffer from serious problems such as localized corrosion or stress corrosion cracking under certain special environmental conditions, such as humid environments containing chloride ions. Furthermore, when titanium alloys come into contact with other metals, galvanic corrosion may occur, further exacerbating the risk of material damage. Therefore, it is crucial to implement effective anti-corrosion measures to extend the service life of titanium aviation fasteners. Summary of the Invention

[0005] In order to improve the wear resistance and corrosion resistance of aviation fasteners, the present application provides a method for coating a molybdenum disulfide protective layer on the surface of titanium aviation fasteners.

[0006] This application provides a method for coating a molybdenum disulfide protective layer on the surface of a titanium aviation fastener, using the following technical solution:

[0007] A method for coating a molybdenum disulfide protective layer on the surface of a titanium aviation fastener comprises the following steps:

[0008] S1. Fastener Surface Treatment: The fastener surface is polished to a surface roughness of 0.05-0.07 microns. After cleaning with an organic solvent, a pulsed laser beam is used to form a honeycomb micropore array on the fastener surface with a pore diameter of 5-10 μm and a depth of 20-50 μm, resulting in a pre-treated fastener.

[0009] S2. Coating with molybdenum disulfide coating: Apply the molybdenum disulfide coating to the pretreated fastener surface, store it at room temperature for 12 hours, and then apply a hydrophobic protective layer;

[0010] S3. Room temperature curing: Curing the fasteners coated with the hydrophobic protective layer at room temperature for 4-6 hours.

[0011] By adopting the above technical solution, the surface of the fastener is finely polished and a honeycomb micropore array is created using a pulsed laser beam, which increases the surface area and coating attachment points, thereby significantly improving the adhesion and uniformity of the coating. Next, a coating containing molybdenum disulfide is applied, and a hydrophobic protective layer is applied thereon. This not only utilizes the characteristics of molybdenum disulfide as a solid lubricant to reduce the friction coefficient and enhance wear resistance, but also further improves the corrosion resistance and water resistance through the hydrophobic layer. Finally, the coating is cured at room temperature to ensure that the coating can achieve optimal physical and chemical stability without destroying its structure. The design of this composite coating significantly enhances the wear resistance, corrosion resistance and service life of titanium aviation fasteners, while simplifying the processing process, making it more suitable for use in the aerospace field where durability and reliability are extremely high requirements.

[0012] Optionally, the molybdenum disulfide coating contains 20-30 parts of polyimide resin, 8-12 parts of molybdenum disulfide, 1-2 parts of aminosilane coupling agent, 0.5-1.5 parts of titanate coupling agent, 20-25 parts of 1-butyl-3-methylimidazole hexafluorophosphate, 5-8 parts of graphene oxide, and 0.5-0.8 parts of benzotriazole.

[0013] Through this technical solution, polyimide resin serves as a high-temperature-resistant matrix, providing mechanical strength and film-forming properties. MoS2 reduces wear through its layered slip structure, and its surface is modified with an aminosilane coupling agent, enhancing interfacial bonding with the resin through -Si-O-Mo bonds. A titanane coupling agent bridges the gap between graphene oxide and the resin, leveraging the two-dimensional interpenetrating structure of GO (graphene oxide) to enhance load-bearing capacity and inhibit MoS2 (molybdenum disulfide) oxidation. Benzotriazole adsorbs on the metal surface to form a passivating film, synergizing with the GO physical barrier to block corrosion pathways. The core mechanism is a "resin matrix - enhanced lubrication - interfacial bonding - corrosion protection" synergy, achieving integrated high wear resistance, high-temperature resistance, and long-term corrosion protection.

[0014] Optionally, the preparation of the molybdenum disulfide coating comprises the following steps:

[0015] (1) dispersing molybdenum disulfide and aminosilane coupling agent in ethanol, ultrasonically treating, centrifuging, washing, and drying to obtain pretreated molybdenum disulfide;

[0016] (2) mixing graphene oxide and titanane coupling agent and ball milling to obtain pretreated graphene oxide;

[0017] (3) Dissolve the polyimide resin in 1-butyl-3-methylimidazole hexafluorophosphate, heat to 55-65°C and stir until completely dissolved, add the pretreated molybdenum disulfide, graphene oxide and benzotriazole in sequence, and ultrasonically disperse them to obtain a slurry, which is the molybdenum disulfide coating.

[0018] By employing the above technical solution, molybdenum disulfide and an aminosilane coupling agent are first ultrasonically dispersed in ethanol and centrifugally washed and dried to enhance their interfacial bonding with the resin matrix. Graphene oxide and the titanane coupling agent are then ball-milled to improve their dispersibility and compatibility with the matrix. Subsequently, the pretreated molybdenum disulfide, graphene oxide, and benzotriazole are sequentially added to a polyimide resin dissolved in an ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate). Ultrasonic dispersion forms a uniform slurry, resulting in a molybdenum disulfide coating with excellent wear resistance and durability.

[0019] Optionally, the hydrophobic protective layer comprises the following raw materials in parts by weight: 3-5 parts of fluorosilane compounds, 1-2 parts of glycidoxypropyltrimethoxysilane, 5-8 parts of perfluoropolyether, 10-15 parts of hydrofluoroether, and 0.5-1 part of methyltrimethoxysilane.

[0020] By adopting the above technical solution, fluorosilane compounds provide low surface energy through long fluorocarbon chains, while perfluoropolyether dynamically wets and fills micropores and reduces the friction coefficient, and the two work together to create a superhydrophobic state. Glycidoxypropyltrimethoxysilane and methyltrimethoxysilane form a dense Si-O-Si network through hydrolysis and condensation. The epoxy group of the former reacts with the underlying polyimide to enhance interfacial bonding, while the latter accelerates crosslinking and shortens the curing time. Hydrofluoroether acts as a solvent to regulate viscosity, and after volatilization, it induces the directional alignment of fluorosilane and perfluoropolyether, forming a micro-nano rough structure. The core mechanism is "low surface energy + micro-nano structure + strong interfacial bonding", ultimately achieving multifunctional protection against wear and corrosion.

[0021] Optionally, the fluorosilane compound is tridecafluorooctyltrimethoxysilane.

[0022] By adopting the above technical solution, tridecafluorooctyltrimethoxysilane has an ultra-low surface energy, which can impart excellent hydrophobic properties to the surface of the protective layer. At the same time, its short carbon chain structure helps to improve solubility in solvents, thereby effectively avoiding the occurrence of crystallization problems. Tridecafluorooctyltrimethoxysilane works synergistically with the glycidoxypropyltrimethoxysilane and methyltrimethoxysilane in the formula to jointly construct a dense Si-O-Si network structure. This structure not only significantly enhances the overall stability and mechanical strength of the coating, but also greatly improves the interfacial bonding between the coating and the underlying molybdenum disulfide coating.

[0023] Optionally, during the pulse laser beam treatment, nitrogen is used as a carrier gas, and hydrogen sulfide gas with a volume concentration of 5-10% is introduced.

[0024] By adopting the above technical solution, hydrogen sulfide gas decomposes into active sulfur atoms and hydrogen under the high temperature of the laser. The sulfur atoms react with the surface of the titanium alloy to form a nano-scale titanium sulfide layer, which significantly improves its wear resistance. At the same time, the sulfur atoms form Ti-S-Mo chemical bonds with the subsequently applied molybdenum disulfide coating, improving the bonding strength of the coating. The honeycomb micropore array enhances the shear resistance of the molybdenum disulfide coating through a mechanical interlocking effect and stores sulfides as a self-lubricating reserve; nitrogen inhibits the oxidation of the titanium surface and maintains the purity of the sulfidation reaction, thereby improving the friction and corrosion resistance of the fastener surface.

[0025] Optionally, the molybdenum disulfide coating is applied at a temperature of 70-90°C.

[0026] By adopting the above technical solution, when heated to 70-90°C, the π electrons in the graphene oxide in the coating and the positrons in the ionic liquid induce the ionic liquid molecules to arrange into a loose structure through the π-π stacking effect, which significantly reduces the overall viscosity of the coating. This helps it form a smoother and continuous coating on the substrate, achieve a more uniform and delicate coating effect, and reduce the possibility of internal defects in the coating. After the temperature drops, the material will return to a viscous state, and the molybdenum disulfide particles will be neatly arranged and fixed on the surface of the material. This vertically arranged structure greatly improves the lubrication performance of the coating and improves the wear resistance of the material.

[0027] Optionally, the molybdenum disulfide coating further includes 1-3 parts of magnesium hydroxysilicate.

[0028] By adopting the above technical solution, hydroxy magnesium silicate has a layered silicate structure, which can synergize with the hexagonal lattice of molybdenum disulfide to further reduce the friction coefficient and improve the load-bearing capacity of the coating.

[0029] In summary, this application has the following beneficial effects:

[0030] 1. This application greatly increases the contact area and adhesion points between the coating and the substrate by finely pre-treating the surface of titanium aviation fasteners and combining it with a honeycomb micropore array formed by a pulsed laser beam, significantly improving the adhesion and uniformity of the coating. A composite coating containing high-performance materials such as molybdenum disulfide is applied, and a hydrophobic protective layer is applied thereon. This not only utilizes the solid lubrication properties of molybdenum disulfide, but also improves corrosion resistance and water resistance through the hydrophobic layer. With these measures working together, the wear resistance and service life of titanium aviation fasteners have been significantly improved, meeting the extremely high durability and reliability requirements of the aerospace field.

[0031] 2. In this application, polyimide resin, graphene oxide, magnesium hydroxysilicate and other ingredients are added to the molybdenum disulfide coating, leveraging its excellent mechanical strength and layered slip properties to significantly reduce the friction coefficient and wear rate. At the same time, the introduction of a hydrophobic protective layer, particularly fluorosilane compounds and perfluoropolyethers, gives the coating ultra-low surface energy and excellent water-repellent properties, effectively preventing the intrusion of moisture and other corrosive media and slowing the oxidative degradation of MoS2.

[0032] 3. The present method significantly reduces the overall viscosity of the molybdenum disulfide coating when applied at 70-90°C, resulting in a smoother and more continuous coating and reducing the likelihood of internal defects. Upon cooling, the material returns to a viscous state, neatly arranging and fixing the molybdenum disulfide particles on the surface, significantly improving the coating's wear resistance. DETAILED DESCRIPTION

[0033] The present application is further described in detail below with reference to the embodiments.

[0034] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or those recommended by the manufacturer. All reagents or instruments used, if the manufacturer is not specified, are commercially available conventional products.

[0035] Molybdenum disulfide (MS) with a particle size of 1-2 μm and a purity of >99% (CAS: 1317-33-5) was purchased from Hubei Xingyan New Materials Technology Co., Ltd. (CAS: 174501-64-5). Diamond polishing fluid was purchased from Shanghai Shuangjin Electronic Technology Co., Ltd.

[0036] Preparation Example

[0037] Preparation Example 1

[0038] A molybdenum disulfide coating, the preparation of which comprises the following steps:

[0039] (1) 1 kg of molybdenum disulfide and 0.15 kg of γ-aminopropyltriethoxysilane (aminosilane coupling agent) were dispersed in 20 L of ethanol and ultrasonically treated at 500 W and 40 kHz for 30 min. The supernatant was removed by centrifugation, and the precipitate was washed 2-3 times with ethanol and dried to obtain pretreated molybdenum disulfide;

[0040] (2) 0.5 kg of graphene oxide and 0.05 kg of isopropyl tris(dioctyl pyrophosphate) titanate were mixed and added to a ball mill. 3 mm zirconium oxide balls were used as the ball milling medium. The mixture was ball milled at 400 rpm / min for 2 h, washed with deionized water, and centrifuged and dried to obtain pretreated graphene oxide.

[0041] (3) 2.5 kg of polyimide resin was dissolved in 2 kg of 1-butyl-3-methylimidazole hexafluorophosphate solution, heated to 60 ° C and stirred until completely dissolved, and pretreated molybdenum disulfide and graphene oxide and 0.05 kg of benzotriazole were added in sequence, and the molybdenum disulfide coating was obtained after ultrasonic dispersion.

[0042] Preparation Example 2

[0043] A molybdenum disulfide coating, the preparation of which comprises the following steps:

[0044] (1) 0.8 kg of molybdenum disulfide and 0.1 kg of γ-aminopropyltriethoxysilane (aminosilane coupling agent) were dispersed in 20 L of ethanol and ultrasonically treated at 500 W and 40 kHz for 30 min. The supernatant was removed by centrifugation, and the precipitate was washed 2-3 times with ethanol and dried to obtain pretreated molybdenum disulfide;

[0045] (2) 0.8 kg of graphene oxide and 0.15 kg of isopropyl tris(dioctyl pyrophosphate) titanate were mixed and added to a ball mill. 3 mm zirconium oxide balls were used as the ball milling medium. The mixture was ball milled at 400 rpm / min for 2 h, washed with deionized water, and centrifuged and dried to obtain pretreated graphene oxide.

[0046] (3) 2 kg of polyimide resin was dissolved in 2.25 kg of 1-butyl-3-methylimidazole hexafluorophosphate solution, heated to 65 ° C and stirred until completely dissolved, and pretreated molybdenum disulfide and graphene oxide and 0.065 kg of benzotriazole were added in sequence, and ultrasonic dispersion was performed to obtain the molybdenum disulfide coating.

[0047] Preparation Example 3

[0048] A molybdenum disulfide coating, the preparation of which comprises the following steps:

[0049] (1) 1.2 kg of molybdenum disulfide and 0.2 kg of γ-aminopropyltriethoxysilane (aminosilane coupling agent) were dispersed in 20 L of ethanol and ultrasonically treated at 500 W and 40 kHz for 30 min. The supernatant was removed by centrifugation, and the precipitate was washed 2-3 times with ethanol and dried to obtain pretreated molybdenum disulfide;

[0050] (2) 0.65 kg of graphene oxide and 0.1 kg of isopropyl tris(dioctyl pyrophosphate) titanate were mixed and added to a ball mill. 3 mm zirconium oxide balls were used as the ball milling medium. The mixture was ball milled at 400 rpm / min for 2 h, washed with deionized water, and centrifuged and dried to obtain pretreated graphene oxide.

[0051] (3) 3 kg of polyimide resin was dissolved in 2.5 kg of 1-butyl-3-methylimidazole hexafluorophosphate solution, heated to 55 °C and stirred until completely dissolved, and pretreated molybdenum disulfide and graphene oxide and 0.08 kg of benzotriazole were added in sequence, and ultrasonic dispersion was performed to obtain the molybdenum disulfide coating.

[0052] Preparation Example 4

[0053] A molybdenum disulfide coating, which differs from Preparation Example 1 in that 0.1 kg of magnesium hydroxysilicate is added in this Preparation Example, and the preparation comprises the following steps:

[0054] (1) 1 kg of molybdenum disulfide and 0.15 kg of γ-aminopropyltriethoxysilane (aminosilane coupling agent) were dispersed in 20 L of ethanol and ultrasonically treated at 500 W and 40 kHz for 30 min. The supernatant was removed by centrifugation, and the precipitate was washed 2-3 times with ethanol and dried to obtain pretreated molybdenum disulfide;

[0055] (2) 0.5 kg of graphene oxide and 0.05 kg of isopropyl tris(dioctyl pyrophosphate) titanate were mixed and added to a ball mill. 3 mm zirconium oxide balls were used as the ball milling medium. The mixture was ball milled at 400 rpm / min for 2 h, washed with deionized water, and centrifuged and dried to obtain pretreated graphene oxide.

[0056] (3) 2.5 kg of polyimide resin was dissolved in 2 kg of 1-butyl-3-methylimidazole hexafluorophosphate solution, heated to 60 ° C and stirred until completely dissolved, and pretreated molybdenum disulfide and graphene oxide, 0.05 kg of benzotriazole, and 0.1 kg of hydroxy magnesium silicate were added in sequence, and ultrasonic dispersion was performed to obtain the molybdenum disulfide coating.

[0057] Preparation Example 5

[0058] A molybdenum disulfide coating, which is different from Preparation Example 4 in that 0.2 kg of hydroxy magnesium silicate is added in this Preparation Example.

[0059] Preparation Example 6

[0060] A molybdenum disulfide coating, which is different from Preparation Example 4 in that 0.3 kg of hydroxy magnesium silicate is added in this Preparation Example.

[0061] Example

[0062] Example 1

[0063] A method for coating a molybdenum disulfide protective layer on the surface of a titanium aviation fastener comprises the following steps:

[0064] S1. Fastener Surface Treatment: The surface of a TC4 titanium alloy screw fastener was mechanically polished using a 0.5 μm diamond polishing slurry to a surface roughness of 0.06 μm. The fastener was then ultrasonically cleaned using acetone and then anhydrous ethanol. After drying, a pulsed laser beam (wavelength 1064 nm, pulse width 100 ns, power 80 W) was used in a nitrogen and 8 vol% hydrogen sulfide mixture to form a honeycomb micropore array on the surface. The pores had a diameter of 8 μm and a depth of 35 μm, resulting in a pretreated fastener.

[0065] S2. Coating of molybdenum disulfide coating: The molybdenum disulfide coating slurry prepared in Preparation Example 1 was heated to 80°C and sprayed onto the screw surface preheated to 80°C using a high-pressure airless spray gun. The wet film thickness was 60 μm. After standing at room temperature for 12 hours, a hydrophobic protective layer was sprayed. The hydrophobic protective layer had a wet film thickness of 20 μm. The hydrophobic layer included: 4 kg of tridecafluorooctyltrimethoxysilane (a fluorosilane compound), 1.5 kg of glycidoxypropyltrimethoxysilane, 8 kg of perfluoropolyether, 12.5 kg of hydrofluoroether, and 0.65 kg of methyltrimethoxysilane.

[0066] S3. Room temperature curing: Curing the screw fastener coated with the hydrophobic protective layer at room temperature for 5 hours to obtain a titanium aviation fastener coated with a molybdenum disulfide protective layer.

[0067] Example 2

[0068] A method for coating a molybdenum disulfide protective layer on the surface of a titanium aviation fastener comprises the following steps:

[0069] S1. Fastener Surface Treatment: The surface of a TC4 titanium alloy screw fastener was mechanically polished using a 0.5 μm diamond polishing slurry to a surface roughness of 0.07 μm. The fastener was then ultrasonically cleaned using acetone and then wastewater ethanol. After drying, a pulsed laser beam (wavelength 1064 nm, pulse width 100 ns, power 80 W) was used in a nitrogen and 5 vol% hydrogen sulfide mixture to form a honeycomb micropore array on the surface. The pores had a diameter of 10 μm and a depth of 50 μm, resulting in the pretreated fastener.

[0070] S2. Coating of molybdenum disulfide coating: The molybdenum disulfide coating slurry prepared in Preparation Example 2 was heated to 70°C and sprayed onto the surface of the fastener preheated to 70°C using a high-pressure airless spray gun to a wet film thickness of 60 μm. After standing at room temperature for 12 hours, a hydrophobic protective layer was sprayed to a wet film thickness of 20 μm; the hydrophobic layer included: 3 kg of tridecafluorooctyltrimethoxysilane (a fluorosilane compound), 2 kg of glycidoxypropyltrimethoxysilane, 5 kg of perfluoropolyether, 10 kg of hydrofluoroether, and 0.5 kg of methyltrimethoxysilane;

[0071] S3. Room temperature curing: The fastener coated with the hydrophobic protective layer is cured at room temperature for 6 hours to obtain a titanium aviation fastener coated with a molybdenum disulfide protective layer.

[0072] Example 3

[0073] A method for coating a molybdenum disulfide protective layer on the surface of a titanium aviation fastener comprises the following steps:

[0074] S1. Fastener Surface Treatment: The surface of a TC4 titanium alloy screw fastener was mechanically polished using a 0.5 μm diamond polishing slurry to a surface roughness of 0.05 μm. The fastener was then ultrasonically cleaned using acetone and then wastewater ethanol. After drying, a pulsed laser beam (wavelength 1064 nm, pulse width 100 ns, power 80 W) was used in a nitrogen and 10 vol% hydrogen sulfide mixture to form a honeycomb micropore array on the surface with a pore diameter of 5 μm and a depth of 20 μm, yielding the pretreated fastener.

[0075] S2. Coating of molybdenum disulfide coating: The molybdenum disulfide coating slurry prepared in Preparation Example 3 was heated to 90°C and sprayed onto the surface of the fastener preheated to 90°C using a high-pressure airless spray gun to a wet film thickness of 60 μm. After standing at room temperature for 12 hours, a hydrophobic protective layer was sprayed. The hydrophobic protective layer had a wet film thickness of 20 μm. The hydrophobic layer included: 5 kg of tridecafluorooctyltrimethoxysilane (a fluorosilane compound), 1 kg of glycidoxypropyltrimethoxysilane, 6.5 kg of perfluoropolyether, 15 kg of hydrofluoroether, and 1 kg of methyltrimethoxysilane.

[0076] S3. Room temperature curing: Curing the fastener coated with the hydrophobic protective layer at room temperature for 4 hours to obtain a titanium aviation fastener coated with a molybdenum disulfide protective layer.

[0077] Example 4

[0078] A method for coating a molybdenum disulfide protective layer on the surface of a titanium aviation fastener is different from Example 1 in that the fluorosilane compound added to the hydrophobic protective layer in this embodiment is trityl fluorosilane.

[0079] Example 5

[0080] A method for coating a molybdenum disulfide protective layer on the surface of a titanium aviation fastener is different from Example 1 in that nitrogen is introduced during pulsed laser beam pretreatment of the fastener in this embodiment.

[0081] Example 6

[0082] A method for coating a molybdenum disulfide protective layer on the surface of a titanium aviation fastener is disclosed. The method differs from Example 1 in that the molybdenum disulfide coating is coated at 50° C. in this embodiment.

[0083] Example 7

[0084] A method for coating a molybdenum disulfide protective layer on the surface of a titanium aviation fastener is different from Example 1 in that the molybdenum disulfide coating is coated at 100° C. in this embodiment.

[0085] Example 8

[0086] A method for coating a molybdenum disulfide protective layer on the surface of a titanium aviation fastener is disclosed. The method differs from Example 1 in that the molybdenum disulfide coating applied in this embodiment is the one prepared in Preparation Example 4.

[0087] Example 9

[0088] A method for coating a molybdenum disulfide protective layer on the surface of a titanium aviation fastener is disclosed. The method differs from Example 1 in that the molybdenum disulfide coating applied in this embodiment is the one prepared in Preparation Example 5.

[0089] Example 10

[0090] A method for coating a molybdenum disulfide protective layer on the surface of a titanium aviation fastener is different from Example 1 in that the molybdenum disulfide coating applied in this embodiment is prepared in Preparation Example 6.

[0091] Comparative Example

[0092] Comparative Example 1

[0093] A method for coating a molybdenum disulfide protective layer on the surface of a titanium aviation fastener is disclosed. The method differs from Example 1 in that a pulsed laser beam is not used to treat the material surface in this comparative example.

[0094] Comparative Example 2

[0095] A method for coating a molybdenum disulfide protective layer on the surface of a titanium aviation fastener is disclosed. The method differs from Example 1 in that graphene oxide and titanane coupling agent are not added to the molybdenum disulfide coating of this comparative example.

[0096] Comparative Example 3

[0097] A method for coating a molybdenum disulfide protective layer on the surface of a titanium aviation fastener is disclosed. The method differs from Example 1 in that an equal amount of methanol is used instead of 1-butyl-3-methylimidazole hexafluorophosphate in the molybdenum disulfide coating of this comparative example.

[0098] Comparative Example 4

[0099] A method for coating a molybdenum disulfide protective layer on the surface of a titanium aviation fastener is disclosed. The method differs from Example 1 in that no aminosilane coupling agent and titanane coupling agent are added to the molybdenum disulfide coating of this comparative example.

[0100] Performance testing

[0101] Detection method

[0102] Friction test: Sliding wear test was conducted using an MMU-10G high-temperature end-face friction and wear tester with a speed of 200 r / min and a load of 10 N to test the friction coefficient.

[0103] High temperature durability: After heat treatment at 300℃ for 2h, the friction coefficient is tested again and the rate of change of the friction coefficient is recorded;

[0104] Corrosion resistance: According to GB / T 10125-2012 "Artificial atmosphere corrosion test salt spray test", the time for no white corrosion products to appear in the neutral salt spray test is recorded.

[0105] Table 1 Test results

[0106]

[0107] Combining Examples 1-3 and Comparative Example 1 and Table 1, it can be seen that the experimental data of Examples 1-3 are all better than those of Comparative Example 1, indicating that pretreatment of the material surface with a pulsed laser beam can enhance the mechanical interlocking effect between the coating and the substrate by forming a honeycomb micropore array, thereby improving the adhesion of the coating and thus improving the corrosion resistance and durability of the coating.

[0108] Combining Examples 1-3 and Comparative Example 2 and Table 1, it can be seen that the experimental data of Examples 1-3 are all better than those of Comparative Example 2, indicating that the addition of graphene oxide treated with a titanane coupling agent to the molybdenum disulfide coating can improve the wear resistance of the coating through interfacial chemical bonding and synergistic effects of two-dimensional sheets.

[0109] Combining Examples 1-3 and Comparative Example 3 and Table 1, it can be seen that the experimental data of Examples 1-3 are all better than those of Comparative Example 3. The failure to add 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid results in an increase in the viscosity of the dispersion system and microcracks in the coating, resulting in a significant decrease in corrosion resistance and durability.

[0110] Combining Examples 1-3 and Comparative Example 4 and Table 1, it can be seen that the experimental data of Examples 1-3 are better than those of Comparative Example 4. When the aminosilane coupling agent and the titanane coupling agent are not added, a better interfacial bonding cannot be formed between the raw materials of the coating, resulting in a decrease in its various performances.

[0111] Combining Example 1 with Example 4 and Table 1, it can be seen that the experimental data of Example 1 are all better than those of Example 4, indicating that the selection of tridecafluorooctyltrimethoxysilane as a fluorosilane compound to be added to the hydrophobic protective layer can form a denser low surface energy film and significantly inhibit the Cl -Penetrate and improve the corrosion resistance of the coating.

[0112] Combining Example 1 with Example 5 and Table 1, it can be seen that the experimental data of Example 1 are all better than those of Example 5. The addition of hydrogen sulfide gas can generate titanium sulfide in situ during laser irradiation, thereby enhancing the friction resistance of the coating.

[0113] Combining Example 1 with Examples 6-7 and Table 1, it can be seen that the experimental data of Example 1 are all better than those of Examples 6-7, indicating that the control of temperature during the coating of the molybdenum disulfide coating affects the performance of the final coating. At an appropriate temperature, the ionic liquid in the molybdenum disulfide coating is aligned with the graphene oxide to form a smooth and continuous coating, thereby improving the wear resistance of the material.

[0114] Combining Example 1 with Examples 8-10 and Table 1, it can be seen that the experimental data of Examples 8-10 are all better than those of Example 1, indicating that the addition of hydroxy magnesium silicate to the molybdenum disulfide coating can synergistically act with molybdenum disulfide to reduce the friction coefficient and improve the wear resistance of the material.

[0115] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A method for coating a molybdenum disulfide protective layer on the surface of a titanium aviation fastener, characterized in that: The steps include: S1. Fastener Surface Treatment: The fastener surface is polished to a surface roughness of 0.05-0.07 microns. After cleaning with an organic solvent, a pulsed laser beam is used to form a honeycomb micropore array on the fastener surface with a pore diameter of 5-10 μm and a depth of 20-50 μm, resulting in a pre-treated fastener. S2. Coating with molybdenum disulfide coating: Apply the molybdenum disulfide coating to the pretreated fastener surface, store it at room temperature for 12 hours, and then apply a hydrophobic protective layer; S3 room temperature curing: The fastener coated with a hydrophobic protective layer is cured at room temperature for 4-6h; The molybdenum disulfide coating preparation comprises the following steps: (1) dispersing molybdenum disulfide and aminosilane coupling agent in ethanol, ultrasonically treating, centrifuging, washing, and drying to obtain pretreated molybdenum disulfide; (2) mixing graphene oxide and titanane coupling agent and ball milling to obtain pretreated graphene oxide; (3) Dissolve the polyimide resin in 1-butyl-3-methylimidazole hexafluorophosphate, heat to 55-65°C and stir until completely dissolved, add the pretreated molybdenum disulfide, graphene oxide and benzotriazole in sequence, and ultrasonically disperse them to obtain a slurry, which is the molybdenum disulfide coating.

2. The method for coating a molybdenum disulfide protective layer on the surface of a titanium aviation fastener according to claim 1, characterized in that: The molybdenum disulfide coating contains the following raw materials in parts by weight: 20-30 parts of polyimide resin, 8-12 parts of molybdenum disulfide, 1-2 parts of aminosilane coupling agent, 0.5-1.5 parts of titanate coupling agent, 20-25 parts of 1-butyl-3-methylimidazole hexafluorophosphate, 5-8 parts of graphene oxide, and 0.5-0.8 parts of benzotriazole.

3. The method for coating a molybdenum disulfide protective layer on the surface of a titanium aviation fastener according to claim 1, characterized in that: The hydrophobic protective layer comprises the following raw materials in parts by weight: 3-5 parts of fluorosilane compounds, 1-2 parts of glycidoxypropyltrimethoxysilane, 5-8 parts of perfluoropolyether, 10-15 parts of hydrofluoroether, and 0.5-1 part of methyltrimethoxysilane.

4. The method for coating a molybdenum disulfide protective layer on the surface of a titanium aviation fastener according to claim 3, characterized in that: The fluorosilane compound is tridecafluorooctyltrimethoxysilane.

5. The method for coating a molybdenum disulfide protective layer on the surface of a titanium aviation fastener according to claim 1, characterized in that: During the pulse laser beam treatment, nitrogen was used as a carrier gas, and hydrogen sulfide gas with a volume concentration of 5-10% was introduced.

6. The method for coating a molybdenum disulfide protective layer on the surface of a titanium aviation fastener according to claim 1, characterized in that: The coating of the molybdenum disulfide coating is carried out at a temperature of 70-90°C.

7. The method for coating a molybdenum disulfide protective layer on the surface of a titanium aviation fastener according to claim 2, characterized in that: The molybdenum disulfide coating further comprises 1-3 parts of magnesium hydroxysilicate.

Images