A wide-temperature-range self-lubricating coating based on boron nitride / graphene composite filler, its preparation method and application

Abstract

This invention provides a wide-temperature-range self-lubricating coating based on boron nitride / graphene composite filler, its preparation method, and its application, belonging to the field of surface protective coating technology. In this invention, modified phenolic resin is used as a high-temperature resistant binder; modified boron nitride / graphene composite material, tungsten disulfide, and fluoride are used as high-temperature lubricating and wear-resistant functional fillers, which can impart excellent temperature resistance, lubrication, and wear resistance to the coating, as well as good bonding ability with the metal substrate. Tungsten disulfide and fluoride can further improve lubricity and wear resistance. The modified boron nitride / graphene composite material can improve its dispersion performance in the system and can improve the interfacial bonding strength with the modified phenolic resin matrix through chemical reaction with the modified phenolic resin. The additives ensure that the coating does not easily settle, the raw materials are uniformly dispersed, and the surface wetting and leveling properties are good. The resulting coating is dense and free of defects such as bubbles and nodules.

Description

Technical Field

[0001] This invention relates to the field of surface protective coating technology, and in particular to a wide-temperature-range self-lubricating coating based on boron nitride / graphene composite filler, its preparation method, and its application. Background Technology

[0002] Engines are the primary power source for high-end equipment such as aircraft, rockets, and ships, playing a crucial role. However, a type of critical metal component within the engine, which is pressed together, is susceptible to high-temperature sintering and fretting wear. Employing advanced lubrication and protection technologies is one of the effective ways to reduce wear and prevent high-temperature sintering.

[0003] Currently, there are three main methods for lubrication protection against high-temperature fretting wear: applying high-temperature grease, surface silver plating, and applying a lubricating coating. At high temperatures, grease oxidizes, deteriorates, thins, and leaks when in contact with air. Furthermore, the acidic substances produced by oxidation promote the decomposition of the thickener, causing the base oil to leak from the thickener and easily contaminate other parts. Another commonly used method is surface silver plating to ensure good anti-adhesion properties of fasteners in high-temperature environments. However, silver plating can cause hydrogen embrittlement, and long-term storage can lead to sulfidation. In recent years, surface treatment methods using lubricating coatings have been increasingly used for lubrication protection of components in high-temperature fretting environments. They are widely used due to their simple and efficient preparation process, strong coating designability, excellent overall performance, and low cost. Molybdenum disulfide coatings are suitable for low-temperature applications, while phosphate-based lubricating coatings offer excellent lubrication performance at medium temperatures, although their load-bearing capacity is slightly lower.

[0004] With the implementation of major equipment projects such as space stations and high thrust-to-weight ratio aero engines, higher demands are being placed on lubrication materials technology that resist high-temperature sintering and fretting wear. For example, components in medium-to-high temperature fretting environments will be subjected to higher temperatures and higher load conditions, and existing coatings can no longer meet lubrication requirements. Therefore, it is urgent to develop a high-temperature resistant self-lubricating coating to solve the problem of high-temperature sintering seizing and fretting wear that easily occurs in connecting and fixing components in medium-to-high temperature / high-to-low temperature alternating, heavy-load, and fretting environments. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a wide-temperature-range self-lubricating coating based on boron nitride / graphene composite filler, its preparation method, and its application. The wide-temperature-range self-lubricating coating provided by this invention is used for lubrication and wear protection of components under harsh and complex working conditions such as fretting, high temperature / high and low temperature alternation, and high load-bearing capacity, significantly improving the stability and service life of the coating.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] This invention provides a wide-temperature-range self-lubricating coating based on boron nitride / graphene composite filler, which is prepared from raw materials comprising the following parts by weight:

[0008] The mixture contains 10-30 parts of modified phenolic resin, 0.5-2 parts of modified boron nitride / graphene composite material, 5-20 parts of tungsten disulfide, 2-8 parts of fluoride, 40-60 parts of dispersion medium, and 0.2-0.3 parts of additives.

[0009] Preferably, the modified phenolic resin includes one or more of silicon-modified phenolic resin, boron-modified phenolic resin, silicon-boron-modified phenolic resin, and molybdenum-modified phenolic resin.

[0010] Preferably, the modified boron nitride / graphene composite material is a boron nitride / graphene composite material modified with single-molecule dopamine.

[0011] Preferably, the monomolecular dopamine-modified boron nitride / graphene composite material is prepared by a method comprising the following steps:

[0012] Under a protective atmosphere, dopamine aqueous solution and boron nitride / graphene composite material are sequentially mixed, separated into solids, washed, and dried to obtain the monomolecular dopamine-modified boron nitride / graphene composite material.

[0013] Preferably, the mass ratio of dopamine to boron nitride / graphene composite material in the dopamine aqueous solution is 10:1 to 1:2, and the mass ratio of boron nitride to graphene in the boron nitride / graphene composite material is 1:1 to 1:4.

[0014] Preferably, the fluoride includes one or more of cerium fluoride, lanthanum fluoride, and barium fluoride.

[0015] Preferably, the additives include wetting and dispersing agents, leveling agents, defoamers, and antisettling agents.

[0016] This invention also provides a method for preparing the wide-temperature-range self-lubricating coating described in the above technical solution, comprising the following steps:

[0017] The modified phenolic resin, modified boron nitride / graphene composite material, tungsten disulfide, fluoride, dispersion medium and additives are mixed to obtain a coating liquid;

[0018] The coating liquid is applied to the substrate surface and then cured to obtain the wide-temperature-range self-lubricating coating based on boron nitride / graphene composite filler.

[0019] Preferably, the curing process involves first drying at 60–80°C for 20–60 min, then holding at 120–150°C for 60–90 min, and finally holding at 180–200°C for 60–180 min.

[0020] This invention also provides the application of the wide-temperature-range self-lubricating coating described above in the field of lubrication, wear resistance and protection.

[0021] This invention provides a wide-temperature-range self-lubricating coating based on boron nitride / graphene composite filler, which is prepared from the following raw materials in parts by weight: 10-30 parts modified phenolic resin, 0.5-2 parts modified boron nitride / graphene composite material, 5-20 parts tungsten disulfide, 2-8 parts fluoride, 40-60 parts dispersion medium, and 0.2-0.3 parts additives.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] In this invention, modified phenolic resin is used as a high-temperature resistant adhesive; modified boron nitride / graphene composite material, tungsten disulfide, and fluorides are used as high-temperature lubricating and wear-resistant functional fillers, which can impart excellent temperature resistance, lubrication, and wear resistance to the coating, as well as good bonding ability with the metal substrate. Tungsten disulfide and fluorides can further improve lubricity and wear resistance. The modified boron nitride / graphene composite material can improve dispersion performance in the system and can enhance interfacial bonding strength with the modified phenolic resin matrix through chemical reaction with the modified phenolic resin. The additives ensure that the coating does not easily settle, the raw materials are uniformly dispersed, and the coating has good wetting and leveling properties on the substrate surface, resulting in a dense coating free of bubbles, nodules, and other defects. The wide-temperature-range self-lubricating coating of this invention can be used for lubrication and wear protection of components under harsh and complex working conditions such as fretting, high / low temperature alternation, and high load-bearing capacity, such as mating surfaces, tenon-and-groove joints, and fastening mechanisms where metal surfaces are pressed together, significantly improving the stability and service life of the coating. Attached Figure Description

[0024] Figure 1 This is a TEM image of the boron nitride / graphene composite material. Detailed Implementation

[0025] This invention provides a wide-temperature-range self-lubricating coating based on boron nitride / graphene composite filler, which is prepared from raw materials comprising the following parts by weight:

[0026] The mixture contains 10-30 parts of modified phenolic resin, 0.5-2 parts of modified boron nitride / graphene composite material, 5-20 parts of tungsten disulfide, 2-8 parts of fluoride, 40-60 parts of dispersion medium, and 0.2-0.3 parts of additives.

[0027] Unless otherwise specified, all raw materials used in this invention are commercially available products in the field.

[0028] In this invention, the raw materials preferably include 15 to 26 parts by weight of modified phenolic resin, more preferably 20 parts by weight. The modified phenolic resin is a high-temperature resistant adhesive that can be cross-linked and cured by heat.

[0029] In this invention, the modified phenolic resin preferably includes one or more of silicon-modified phenolic resin, boron-modified phenolic resin, silicon-boron-modified phenolic resin, and molybdenum-modified phenolic resin.

[0030] Based on the mass fraction of the modified phenolic resin, the raw materials preferably include 0.75 to 1 part by mass of modified boron nitride / graphene composite material, more preferably 0.8 parts by mass. The modified boron nitride / graphene composite material is a high-temperature lubricating and wear-resistant functional filler, which can impart excellent temperature resistance, lubrication, wear resistance and good bonding ability with metal substrate to the coating.

[0031] In this invention, the modified boron nitride / graphene composite material is preferably a boron nitride / graphene composite material modified with single-molecule dopamine.

[0032] In this invention, the monomolecular dopamine-modified boron nitride / graphene composite material is preferably prepared by a method comprising the following steps:

[0033] Under a protective atmosphere, dopamine aqueous solution and boron nitride / graphene composite material are sequentially mixed, separated into solids, washed, and dried to obtain the monomolecular dopamine-modified boron nitride / graphene composite material.

[0034] In this invention, the mass ratio of dopamine to boron nitride / graphene composite material in the dopamine aqueous solution is preferably 1:2 to 1:10, and the mass ratio of boron nitride to graphene in the boron nitride / graphene composite material is preferably 1:1 to 1:4, more preferably 1:2 to 1:3.

[0035] In this invention, the concentration of the dopamine aqueous solution is preferably 0.5 mg / mL.

[0036] In this invention, the protective atmosphere is preferably nitrogen.

[0037] In this invention, the mixing is preferably stirring, the stirring speed is preferably 500 rpm, and the stirring time is preferably 4 hours.

[0038] In this invention, the solid-liquid separation is preferably performed by centrifugation. This invention does not impose any special limitations on the parameters of the centrifugation, and parameters well known to those skilled in the art can be used.

[0039] The present invention does not impose any particular limitation on the specific method of washing and drying; any method known to those skilled in the art can be used.

[0040] In this invention, the boron nitride / graphene composite material is preferably prepared by a method comprising the following steps:

[0041] Boron nitride was mixed with urea and wet-milled to obtain amino-modified boron nitride;

[0042] The amino-modified boron nitride and graphene were mixed with water and then subjected to modification, solid-liquid separation and drying in sequence to obtain the boron nitride / graphene composite material.

[0043] In this invention, the mass ratio of boron nitride to urea is preferably 1:10.

[0044] In this invention, the wet milling time is preferably 24 hours.

[0045] After the wet milling is completed, the present invention preferably removes the suspended impurities by centrifugation to obtain the amino-modified boron nitride.

[0046] In this invention, the mixing is preferably ultrasonically treated, and the ultrasonic treatment time is preferably 20 minutes.

[0047] In this invention, the modification temperature is preferably 80°C, and the modification time is preferably 6 hours.

[0048] In this invention, the solid-liquid separation is preferably performed by vacuum filtration.

[0049] Based on the mass fraction of the modified phenolic resin, the raw material preferably includes 6 to 18 parts by mass of tungsten disulfide, more preferably 10 to 17 parts, and most preferably 16 parts, wherein the tungsten disulfide can improve lubrication performance.

[0050] In this invention, the particle size of the tungsten disulfide is preferably 500 nm to 10 μm, more preferably 1 to 5 μm.

[0051] Based on the mass fraction of the modified phenolic resin, the raw material preferably includes 3 to 7 parts by mass of fluoride, more preferably 6 parts by mass, and the fluoride can improve lubricity and wear resistance.

[0052] In this invention, the fluoride preferably includes one or more of cerium fluoride, lanthanum fluoride, and barium fluoride.

[0053] In this invention, the particle size of the fluoride is preferably 5 to 10 μm.

[0054] Based on the mass fraction of the modified phenolic resin, the raw materials preferably include 0.23 to 0.25 parts by mass of additives.

[0055] In this invention, the additives preferably include wetting and dispersing agents, leveling agents, defoamers, and antisettling agents.

[0056] Based on the mass fraction of the modified phenolic resin, the mass fractions of the wetting and dispersing agent, leveling agent, defoamer, and anti-settling agent in the raw materials are preferably 0.05 to 0.075 parts each.

[0057] In this invention, the wetting and dispersing agent is preferably Tech-5065, Tech-5063 or Tech-5611.

[0058] In this invention, the leveling agent is preferably Tech-2733 or Tech-100A.

[0059] In this invention, the defoamer is preferably Tech-386N.

[0060] In this invention, the anti-settling agent is preferably polyamide wax.

[0061] Based on the mass fraction of the modified phenolic resin, the raw material preferably includes 50 to 55 parts by mass of a dispersion medium.

[0062] In this invention, the dispersion medium is preferably a mixed solvent of n-butanol, butyl acetate and N-methylpyrrolidone.

[0063] In this invention, the mass fraction of n-butanol in the mixed solvent is preferably 30% to 50%, the mass fraction of butyl acetate is preferably 30% to 50%, and the mass fraction of N-methylpyrrolidone is preferably 10% to 20%.

[0064] This invention also provides a method for preparing the wide-temperature-range self-lubricating coating described in the above technical solution, comprising the following steps:

[0065] The modified phenolic resin, modified boron nitride / graphene composite material, tungsten disulfide, fluoride, dispersion medium and additives are mixed to obtain a coating liquid;

[0066] The coating liquid is applied to the substrate surface and then cured to obtain the wide-temperature-range self-lubricating coating based on boron nitride / graphene composite filler.

[0067] The present invention mixes the modified phenolic resin, the modified boron nitride / graphene composite material, tungsten disulfide, fluoride, dispersion medium and additives to obtain a coating liquid.

[0068] In this invention, the coating liquid preferably also includes butanone.

[0069] In this invention, the mixture obtained by mixing is preferably ground in a planetary ball mill to obtain a dry film lubricant, and the dry film lubricant is diluted with methyl ethyl ketone to obtain the coating liquid.

[0070] In this invention, the grinding speed is preferably 300-600 rpm, the grinding time is preferably 6-24 h, and the grinding is preferably filtered using a 200-mesh filter cloth.

[0071] In this invention, the mass ratio of butanone to dry film lubricant is preferably 2 to 3:1.

[0072] The present invention obtains the coating liquid, coats the coating liquid on the substrate surface, and then cures it to obtain the wide temperature range self-lubricating coating based on boron nitride / graphene composite filler.

[0073] In this invention, the substrate is preferably a metal substrate.

[0074] In this invention, the substrate is preferably sandblasted before coating to achieve a surface roughness of 1.5 to 2.5 μm.

[0075] In this invention, the coating is preferably applied by spraying.

[0076] In this invention, the coating thickness is preferably 5 to 40 μm.

[0077] In this invention, the curing process is preferably carried out by first drying at 60-80°C for 20-60 min, then holding at 120-150°C for 60-90 min, and finally holding at 180-200°C for 60-180 min. More preferably, it is carried out by first drying at 60-80°C for 30 min, then holding at 120-150°C for 75-80 min, and finally holding at 180-200°C for 120-150 min.

[0078] This invention also provides the application of the wide-temperature-range self-lubricating coating described above in the field of lubrication, wear resistance and protection.

[0079] The present invention preferably uses the wide temperature range self-lubricating coating for lubrication and wear protection of components under harsh and complex working conditions such as micro-motion, high temperature / high and low temperature alternation, and high load-bearing capacity.

[0080] In this invention, the high temperature is preferably no greater than 400°C; the micro-motion is preferably less than 100μm; the temperature range of the high and low temperature alternation is preferably room temperature to 400°C; and the maximum load is preferably at the GPa level.

[0081] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0082] Test methods and standards:

[0083] 1) Bonding strength test:

[0084] Cross-cut adhesion test, paint film cross-cut tester, adhesion ≤ Grade 1.

[0085] 2) Alternating high and low temperatures:

[0086] The coating will not peel off after 100 cycles of high and low temperature shocks (400℃ for 4 hours, then alternating with room temperature for 4 hours) from room temperature to 400℃.

[0087] 3) Friction coefficient test:

[0088] CSM high-temperature friction testing machine, point-to-surface contact, with a 6mm diameter high-temperature alloy ball as the mating element, frequency 1Hz, load 5N, time 4h, temperature: 25℃, 400℃.

[0089] 4) Wear rate test:

[0090] The wear resistance of the coating was tested using a CSM high-temperature friction testing machine. The wear rate was obtained using the formula W = ΔV / (S·P), where ΔV is the wear volume change (measured using a probe-type surface wear gauge), S is the stroke, and P is the load. All friction and wear performance tests were performed three times, and the average value was calculated.

[0091] 5) Load-bearing life test:

[0092] The bearing time of 4450N was tested using a Falex pin and V-block friction and wear tester.

[0093] The preparation steps of the boron nitride / graphene composite material in this embodiment of the invention are as follows: First, boron nitride and urea are mixed at a mass ratio of 1:10 and wet-milled for 24 hours to obtain amino-modified boron nitride. The suspension impurities are removed by centrifugation. Then, amino-modified boron nitride and GO are mixed in deionized water at a mass ratio of 1:3 and ultrasonically treated for 20 minutes. The mixture is then stirred and reacted at 80°C for 6 hours. Finally, the mixture is filtered and dried at 80°C to obtain the boron nitride / graphene composite material.

[0094] TEM images of the obtained boron nitride / graphene composite material are shown below. Figure 1 .

[0095] The preparation steps of the modified boron nitride / graphene composite material in this embodiment of the invention are as follows:

[0096] 0.5 g of boron nitride / graphene composite material was added to 100 mL of a 0.5 mg / mL dopamine aqueous solution. The mixture was stirred at 500 rpm for 4 h under nitrogen protection. After centrifugation, washing, and drying, monomolecular dopamine-modified boron nitride / graphene composite material was obtained.

[0097] In embodiments of the present invention, the term "parts" refers to parts by mass.

[0098] Example 1

[0099] Weigh 0.5 parts of modified boron nitride / graphene composite material, 10 parts of tungsten disulfide, 2 parts of cerium fluoride, 15 parts of silicon-modified phenolic resin, 0.07 parts of Tech-5063, 0.05 parts of Tech-2733, 0.04 parts of Tech-386N, 0.05 parts of polyamide wax, 10 parts of butyl acetate, 10 parts of n-butanol, and 20 parts of N-methylpyrrolidone. After mixing evenly, place the mixture into a ball mill jar and grind the coating at a speed of 400 r / min for 18 h. After filtering with a 200-mesh filter cloth, obtain a dry film lubricant.

[0100] Five parts of the ball-milled dry film lubricant were dispersed in 10 parts of methyl ethyl ketone and stirred thoroughly. The mixture was then sprayed onto the surface of a sandblasted metal substrate (roughness Ra = 1.2 μm). After the coating was surface dry, it was cured at 60°C for 30 min, then at 120°C for 60 min, and finally heat-treated at 180°C for 120 min to obtain a wide-temperature-range self-lubricating coating. Performance tests were then conducted.

[0101] Example 2

[0102] Weigh out 0.75 parts of modified boron nitride graphene composite material, 15 parts of tungsten disulfide, 2 parts of cerium fluoride, 15 parts of silicon-modified phenolic resin, 0.05 parts of Tech-5065, 0.05 parts of Tech-100A, 0.05 parts of Tech-386N, 0.05 parts of polyamide wax, 15 parts of butyl acetate, 5 parts of n-butanol, and 20 parts of N-methylpyrrolidone. After mixing evenly, place the mixture into a ball mill jar and grind the coating at a speed of 300 r / min for 18 h. Then filter it with a 200-mesh filter cloth to obtain a dry film lubricant.

[0103] Five parts of the ball-milled dry film lubricant were dispersed in 10 parts of methyl ethyl ketone and stirred thoroughly. The mixture was then sprayed onto the surface of a sandblasted metal substrate (roughness Ra = 1.5 μm). After the coating was surface dry, it was cured at 60°C for 60 min, then at 120°C for 60 min, and finally heat-treated at 180°C for 180 min to obtain a wide-temperature-range self-lubricating coating. Performance tests were then conducted.

[0104] Example 3

[0105] Weigh 1.0 part of modified boron nitride / graphene composite material, 6 parts of tungsten disulfide, 3 parts of cerium fluoride, 20 parts of silicon-modified phenolic resin, 0.05 parts of Tech-5063, 0.05 parts of Tech-2733, 0.05 parts of Tech-386N, 0.1 parts of polyamide wax, 15 parts of butyl acetate, 10 parts of n-butanol, and 15 parts of N-methylpyrrolidone. After mixing evenly, place the mixture into a ball mill jar and grind the coating at a speed of 400 r / min for 10 h. Then filter it with a 200 mesh filter cloth to obtain a dry film lubricant.

[0106] Five parts of the ball-milled dry film lubricant were dispersed in 10 parts of methyl ethyl ketone and stirred thoroughly. The mixture was then sprayed onto the surface of a sandblasted metal substrate (roughness Ra = 2.0 μm). After the coating was surface dry, it was cured at 60°C for 30 min, then at 120°C for 60 min, and finally heat-treated at 180°C for 120 min to obtain a wide-temperature-range self-lubricating coating. Performance tests were then conducted.

[0107] Example 4

[0108] Weigh out 0.8 parts of modified boron nitride / graphene composite material, 18 parts of tungsten disulfide, 6 parts of cerium fluoride, 26 parts of silicon-modified phenolic resin, 0.05 parts of Tech-5611, 0.05 parts of Tech-100A, 0.05 parts of Tech-386N, 0.05 parts of polyamide wax, 15 parts of butyl acetate, 20 parts of n-butanol, and 20 parts of N-methylpyrrolidone. After mixing evenly, place the mixture into a ball mill jar and grind the coating at a speed of 500 r / min for 12 h. Then filter it with a 200-mesh filter cloth to obtain a dry film lubricant.

[0109] Five parts of the ball-milled dry film lubricant were dispersed in 10 parts of methyl ethyl ketone and stirred thoroughly. The mixture was then sprayed onto the surface of a sandblasted metal substrate (roughness Ra = 2.2 μm). After the coating was surface dry, it was cured at 60°C for 30 min, then at 120°C for 75 min, and finally heat-treated at 180°C for 180 min to obtain a wide-temperature-range self-lubricating coating. Performance tests were then conducted.

[0110] Example 5

[0111] Weigh out 0.8 parts of modified boron nitride / graphene composite material, 17 parts of tungsten disulfide, 7 parts of lanthanum fluoride, 26 parts of boron-modified phenolic resin, 0.05 parts of Tech-5065, 0.05 parts of Tech-2733, 0.05 parts of Tech-386N, 0.05 parts of polyamide wax, 25 parts of butyl acetate, 20 parts of n-butanol, and 10 parts of N-methylpyrrolidone. After mixing evenly, place the mixture into a ball mill jar and grind the coating at a speed of 500 r / min for 10 h. Then filter it with a 200-mesh filter cloth to obtain a dry film lubricant.

[0112] Five parts of the ball-milled dry film lubricant were dispersed in 10 parts of methyl ethyl ketone and stirred thoroughly. The mixture was then sprayed onto the surface of a sandblasted metal substrate (roughness Ra = 1.2 μm). After the coating was surface dry, it was cured at 80°C for 30 min, then at 150°C for 75 min, and finally heat-treated at 200°C for 180 min to obtain a wide-temperature-range self-lubricating coating. Performance tests were then conducted.

[0113] Example 6

[0114] Weigh out 0.8 parts of modified boron nitride / graphene composite material, 17 parts of tungsten disulfide, 1 part of lanthanum fluoride, 6 parts of barium fluoride, 26 parts of borosilicate modified phenolic resin, 0.06 parts of Tech-5063, 0.05 parts of Tech-2733, 0.06 parts of Tech-386N, 0.06 parts of polyamide wax, 25 parts of butyl acetate, 20 parts of n-butanol, and 10 parts of N-methylpyrrolidone. After mixing evenly, place the mixture into a ball mill jar and grind the coating at a speed of 500 r / min for 10 h. Then filter it with a 200 mesh filter cloth to obtain a dry film lubricant.

[0115] Five parts of the ball-milled dry film lubricant were dispersed in 10 parts of methyl ethyl ketone and stirred thoroughly. The mixture was then sprayed onto the surface of a sandblasted metal substrate (roughness Ra = 1.2 μm). After the coating was surface dry, it was cured at 80°C for 30 min, then at 150°C for 75 min, and finally heat-treated at 200°C for 180 min to obtain a wide-temperature-range self-lubricating coating. Performance tests were then conducted.

[0116] Example 7

[0117] Weigh out 0.6 parts of modified boron nitride / graphene composite material, 17 parts of tungsten disulfide, 3 parts of lanthanum fluoride, 4 parts of barium fluoride, 25 parts of borosilicate modified phenolic resin, 0.06 parts of Tech-5063, 0.05 parts of Tech-2733, 0.06 parts of Tech-386N, 0.06 parts of polyamide wax, 25 parts of butyl acetate, 20 parts of n-butanol, and 10 parts of N-methylpyrrolidone. After mixing evenly, place the mixture into a ball mill jar and grind the coating at a speed of 500 r / min for 10 h. Then filter it with a 200 mesh filter cloth to obtain a dry film lubricant.

[0118] Five parts of the ball-milled dry film lubricant were dispersed in 10 parts of methyl ethyl ketone and stirred thoroughly. The mixture was then sprayed onto the surface of a sandblasted metal substrate (roughness Ra = 1.2 μm). After the coating was surface dry, it was cured at 80°C for 30 min, then at 150°C for 75 min, and finally heat-treated at 200°C for 180 min to obtain a wide-temperature-range self-lubricating coating. Performance tests were then conducted.

[0119] Example 8

[0120] Weigh out 0.8 parts of modified boron nitride / graphene composite material, 17 parts of tungsten disulfide, 1 part of lanthanum fluoride, 6 parts of barium fluoride, 26 parts of boron-modified phenolic resin, 0.06 parts of Tech-5063, 0.05 parts of Tech-2733, 0.06 parts of Tech-386N, 0.06 parts of polyamide wax, 25 parts of butyl acetate, 20 parts of n-butanol, and 10 parts of N-methylpyrrolidone. After mixing evenly, place the mixture into a ball mill jar and grind the coating at a speed of 500 r / min for 10 h. Then filter it with a 200-mesh filter cloth to obtain a dry film lubricant.

[0121] Five parts of the ball-milled dry film lubricant were dispersed in 10 parts of methyl ethyl ketone and stirred thoroughly. The mixture was then sprayed onto the surface of a sandblasted metal substrate (roughness Ra = 1.2 μm). After the coating was surface dry, it was cured at 80°C for 30 min, then at 150°C for 75 min, and finally heat-treated at 200°C for 180 min to obtain a wide-temperature-range self-lubricating coating. Performance tests were then conducted.

[0122] Table 1 shows the performance test results of the wide temperature range self-lubricating coatings in Examples 1 to 8. It can be seen that the wide temperature range self-lubricating coating of the present invention is suitable for lubrication and protection of connected and fixed components under multiple working conditions such as high temperature / high and low temperature alternation, micro-motion, and high load-bearing capacity. For example, it is suitable for metal surfaces that are pressed together, such as joint surfaces, tenon and mortise fits and fastening mechanisms. It can greatly improve the stability and service life of the components.

[0123] Table 1. Performance test results of the wide-temperature-range self-lubricating coatings in Examples 1-8

[0124]

[0125]

[0126] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A wide-temperature-range self-lubricating coating based on boron nitride / graphene composite filler, characterized in that, It is made from raw materials comprising the following parts by weight: 10-30 parts of modified phenolic resin, 0.5-2 parts of modified boron nitride / graphene composite material, 5-20 parts of tungsten disulfide, 2-8 parts of fluoride, 40-60 parts of dispersion medium and 0.2-0.3 parts of additives; The modified phenolic resin includes one or more of the following: silicon-modified phenolic resin, boron-modified phenolic resin, silicon-boron-modified phenolic resin, and molybdenum-modified phenolic resin. The modified boron nitride / graphene composite material is a boron nitride / graphene composite material modified with single-molecule dopamine. The fluoride includes one or more of cerium fluoride, lanthanum fluoride and barium fluoride; The boron nitride / graphene composite material is prepared by a method comprising the following steps: Boron nitride was mixed with urea and wet-milled to obtain amino-modified boron nitride; The amino-modified boron nitride and graphene were mixed with water and then subjected to modification, solid-liquid separation and drying to obtain the boron nitride / graphene composite material.

2. The wide temperature range self-lubricating coating according to claim 1, characterized in that, The monomolecule dopamine-modified boron nitride / graphene composite material is prepared by a method comprising the following steps: Under a protective atmosphere, dopamine aqueous solution and boron nitride / graphene composite material are sequentially mixed, separated into solids, washed, and dried to obtain the monomolecular dopamine-modified boron nitride / graphene composite material.

3. The wide temperature range self-lubricating coating according to claim 2, characterized in that, The mass ratio of dopamine to boron nitride / graphene composite material in the dopamine aqueous solution is 1:2 to 1:10, and the mass ratio of boron nitride to graphene in the boron nitride / graphene composite material is 1:1 to 1:

4.

4. The wide temperature range self-lubricating coating according to claim 1, characterized in that, The additives include wetting and dispersing agents, leveling agents, defoamers, and anti-settling agents.

5. The method for preparing the wide-temperature-range self-lubricating coating according to any one of claims 1 to 4, characterized in that, Includes the following steps: The modified phenolic resin, modified boron nitride / graphene composite material, tungsten disulfide, fluoride, dispersion medium and additives are mixed to obtain a coating liquid; The coating liquid is applied to the substrate surface and then cured to obtain the wide-temperature-range self-lubricating coating based on boron nitride / graphene composite filler.

6. The preparation method according to claim 5, characterized in that, The curing process involves first drying at 60–80°C for 20–60 minutes, then holding at 120–150°C for 60–90 minutes, and finally holding at 180–200°C for 60–180 minutes.

7. The application of the wide temperature range self-lubricating coating according to any one of claims 1 to 4 in the field of lubrication, wear resistance and protection.

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