A method for preparing a coating

Abstract

The present application mainly solves the technical problem of providing a new preparation method of coating, which has the advantages of good wear resistance for high-temperature-resistant solid lubricating coating, and the technical scheme is: a preparation method of coating, comprising: modifying and treating a mixture comprising polyimide, solid lubricant with polyimide precursor in a solvent; wherein the solvent comprises an aprotic polar solvent; the solid lubricant comprises molybdenum disulfide and graphite.

Description

Technical Field

[0001] This invention relates to a method for preparing a coating, the obtained coating, the application of the coating in the manufacture of a high-temperature resistant solid lubricating coating, and a method for manufacturing a high-temperature resistant solid lubricating coating. Background Technology

[0002] Solid lubrication generally refers to the technique of lubricating the surfaces of friction pairs using solid powders or thin films. Solid lubricant coatings typically possess low shear strength and readily adhere to the friction pair surfaces, forming a continuous and stable film. In this case, the solid lubricant coating isolates the direct contact between the friction pairs, with friction occurring within the film produced by the coating, achieving friction reduction and wear resistance. Matrix resin is a commonly used component in solid lubricant coatings. The purpose of using a matrix resin is that the coating itself can isolate direct contact between the friction pair surfaces, while the coating itself has low frictional damping. The matrix resin coating forms a transfer film on the mating metal surfaces, isolating direct contact between the friction surfaces and achieving friction reduction and wear resistance, among other effects. Due to its low friction and wear characteristics, excellent adhesion, and excellent thermal stability, polyimide solid lubricant coatings are often used as the matrix resin in high-temperature resistant solid lubricant coatings. In solid lubricant coatings, although the matrix resin plays the aforementioned important role, the key friction-reducing and wear-resistant effect is achieved by solid lubricant fillers. They typically have low shear strength and reduce the coefficient of friction and wear rate between friction pairs through their own physical or chemical properties. Molybdenum disulfide and graphite are the most common solid lubricant fillers, and the combined use of molybdenum disulfide and graphite will have a synergistic lubrication effect. For example, CN101463288A discloses a technology using polyimide as the matrix resin and molybdenum disulfide and graphite as solid lubricant fillers. In order to improve the compatibility between polyimide and solid lubricant fillers, γ-glycidoxypropyltrimethylsilane is used as a coupling agent. This coupling agent is difficult to obtain commercially, or it may refer to the common coupling agent γ-glycidoxypropyltrimethoxysilane. However, both γ-glycidoxypropyltrimethylsilane and γ-glycidoxypropyltrimethoxysilane contain a considerable proportion of aliphatic groups. Aliphatic groups have poor high-temperature resistance, which affects the compatibility between the matrix resin and solid lubricant during high-temperature use of the coupling agent in the coating, and affects the wear resistance of the high-temperature solid lubricant coating. Summary of the Invention

[0003] One of the technical problems to be solved by the present invention is to provide a new method for preparing a coating, which has the advantages of low friction coefficient and low wear rate when used as a high-temperature resistant solid lubricating coating.

[0004] To solve one of the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0005] A method for preparing a coating, comprising:

[0006] In a solvent, a mixture comprising the following components is modified with a polyimide precursor: polyimide and a solid lubricant; wherein the solvent includes an aprotic polar solvent; and the solid lubricant includes molybdenum disulfide and graphite.

[0007] We found that coatings obtained by modifying a mixture containing polyimide, molybdenum disulfide, and graphite with polyimide precursors, when manufactured into solid lubricating coatings, exhibit excellent wear resistance, with a low coefficient of friction and low wear rate.

[0008] In the above technical solution, the preferred aprotic polar solvent is at least one of dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone.

[0009] In the above technical solution, the preferred polyimide precursor includes:

[0010] (1) Aromatic dianhydrides;

[0011] (2) Aromatic diamines.

[0012] More preferably, the molar ratio of the above-mentioned component (1) to the above-mentioned component (2) is 0.90 to 1.10, for example, but not limited to 0.92, 0.94, 0.96, 0.98, 1.0, 1.02, 1.04, 1.06, 1.08, etc.

[0013] Of the above technical solutions, the preferred option, by weight, is:

[0014] The polyimide precursor is 30 to 60 parts, for example, but not limited to 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, etc.;

[0015] The polyimide is in the range of 50 to 300 parts, for example, but not limited to 60 parts, 70 parts, 80 parts, 90 parts, 100 parts, 110 parts, 120 parts, 130 parts, 140 parts, 150 parts, 160 parts, 170 parts, 180 parts, 190 parts, 200 parts, 210 parts, 220 parts, 230 parts, 240 parts, 250 parts, 260 parts, 270 parts, 280 parts, 290 parts, etc.

[0016] The molybdenum disulfide is 1 to 20 parts, for example, but not limited to 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, etc.

[0017] The graphite is 1 to 10 parts, for example, but not limited to 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, etc.;

[0018] The aprotic solvent is 1000 parts.

[0019] In the above technical solution, the preferred temperature for modification treatment is 5 to 30°C, such as, but not limited to, 6°C, 7°C, 8°C, 9°C, 10°C, 11°C, 12°C, 13°C, 14°C, 15°C, 16°C, 17°C, 18°C, 19°C, 20°C, 21°C, 22°C, 25°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, etc.

[0020] In the above technical solution, the preferred modification treatment time is 1 to 20 hours, such as, but not limited to, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours, 7.5 hours, 8 hours, 8.5 hours, 9 hours, 9.5 hours, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 hours, etc.

[0021] This invention does not impose any particular limitation on the specific structure of the polyimide; however, the polyimide in the specific embodiments of this invention is synthesized according to the polyimide synthesis method disclosed in CN110713598A, specifically as follows:

[0022] In an aprotic polar solvent, aromatic diamine and aromatic dianhydride react at 5–30°C to obtain a polyamic acid solution, which is then reacted in the presence of an imidization accelerator and a chemical dehydrating agent to obtain a crude polyimide solution. Then, under stirring, the crude polyimide solution is slowly added to a polyimide precipitation solvent, filtered, and dried to obtain polyimide powder.

[0023] The present invention does not impose any particular limitation on the aromatic dianhydride in the polyimide precursor and / or the aromatic dianhydride in the polyimide synthesis method, for example, but not limited to, the aromatic dianhydride in the polyimide precursor and the aromatic dianhydride in the polyimide synthesis method being independently selected from at least one of the following groups: methyl benzoic acid dianhydride, 4,4'-biphenyl ether dianhydride, 2,3,3',4'-diphenyl ether tetracarboxylic acid dianhydride and 3,3',4,4'-benzophenone tetracarboxylic acid dianhydride.

[0024] The present invention does not impose any particular limitation on the aromatic diamine in the polyimide precursor and / or the aromatic diamine in the polyimide synthesis method, for example, but not limited to, the aromatic diamine in the polyimide precursor and the aromatic diamine in the polyimide synthesis method being independently selected from at least one of the substances grouped together with p-phenylenediamine, 4,4'-diaminodiphenyl ether, 4,4'-diaminobenzophenone, 4,4'-ethylenediphenylamine and 3,3'-methylenediphenylamine.

[0025] In particular, when the aromatic diamine used for modification treatment includes both 4,4'-diaminodiphenyl ether and p-phenylenediamine, the two diamines have a significant synergistic effect in reducing wear rate and friction coefficient. In this case, a molar ratio of 4,4'-diaminodiphenyl ether to p-phenylenediamine of 2 to 9 is more preferred, for example, but not limited to, 3, 4, 5, 6, 7, 8, etc.

[0026] In the above technical solution, molybdenum disulfide and graphite are insoluble in the solvent. Throughout the modification process and in the final coatable coating, they are suspended in the solvent as solid particles. To increase suspension stability and achieve a more uniform high-temperature resistant solid lubricant coating with improved wear resistance, a reasonably small particle diameter for molybdenum disulfide and graphite is preferred. Fine-diameter molybdenum disulfide and graphite can be selected from commercially available sources. If the particles obtained from commercial sources are coarse, they can be ground using methods known in the prior art. Since the modification method of this invention uses a solvent, it is also convenient to wet-mill the molybdenum disulfide and graphite together or separately in the solvent before modification.

[0027] For comparative purposes only, in this specific embodiment of the invention, molybdenum disulfide is produced by wet milling commercially available molybdenum disulfide (0.1–10 μm, produced by Shanghai Colloidal Chemical Plant) in a sand mill using N,N-dimethylacetamide as a wet milling solvent until the particle size D95 is 1 μm, resulting in a molybdenum disulfide wet milling solution, which is then used. The weight ratio of N,N-dimethylacetamide to commercially available molybdenum disulfide is 500:10.

[0028] For comparative purposes only, the graphite in the specific embodiment of this invention is produced by wet milling commercially available graphite (0.1-10 μm, produced by Shanghai Colloidal Chemical Plant) in a sand mill using N,N-dimethylacetamide as a wet milling solvent until the particle size D95 is 1 μm, obtaining a graphite wet milling slurry, which is then used in the form of this graphite wet milling slurry. The weight ratio of N,N-dimethylacetamide to commercially available graphite is 500:8.

[0029] For comparison only, the specific operation method of the coating preparation method of the present invention can be as follows:

[0030] The molybdenum disulfide and graphite required for the coating are dispersed in a solvent, and the aromatic diamine in the polyimide and polyimide precursor is dissolved in an aprotic polar solvent. Aromatic dianhydride is added while maintaining the required modification treatment temperature, and then the modification treatment is carried out for the required time.

[0031] The second technical problem to be solved by the present invention is to provide a coating.

[0032] To solve the second technical problem mentioned above, the technical solution of the present invention is as follows:

[0033] The coating obtained by any one of the preparation methods according to one of the technical solutions to the above-mentioned technical problems.

[0034] The third technical problem to be solved by the present invention is to provide an application of the above-mentioned coating.

[0035] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0036] The above-mentioned coatings are used in the manufacture of high-temperature resistant solid lubricating coatings.

[0037] The fourth technical problem to be solved by the present invention is to provide a method for manufacturing a high-temperature resistant solid lubricating coating.

[0038] To solve the fourth technical problem mentioned above, the technical solution of the present invention is as follows:

[0039] A method for manufacturing a high-temperature resistant solid lubricant coating includes:

[0040] (i) Apply the coating to the surface of the material to be coated to obtain a precursor coating;

[0041] (ii) Heat treatment transforms the precursor coating into a high-temperature resistant solid lubricant coating.

[0042] In the above technical solutions, the coating method can be any of those known in the art, such as spraying, brushing, or dipping.

[0043] In the above technical solution, there are no special restrictions on the material to be coated, and those skilled in the art can make reasonable choices. For example, it can be coated on the surface of metal (such as steel and aluminum) or on the surface of non-metallic materials such as ceramics.

[0044] In the above technical solution, the preferred step (ii) heat treatment includes at least two stages:

[0045] Previous stage

[0046] The solvent in the precursor coating is removed below the boiling point of the solvent to obtain a cured intermediate coating;

[0047] Later stage

[0048] The high-temperature resistant solid lubricating coating is obtained by curing the intermediate coating.

[0049] In the above technical solution, the temperature t of the previous stage treatment preferably conforms to t=aB, where B is the boiling point of the solvent and a is 0.4~0.9, for example, but not limited to a being 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, etc.

[0050] In the above technical solution, the preferred processing time for the first stage is 5 to 10 hours, such as, but not limited to, 6 hours, 6.5 hours, 7 hours, 7.5 hours, 8 hours, 8.5 hours, 9 hours, 9.5 hours, etc.

[0051] In the above technical solution, the preferred temperature for the later stage processing is 200-300℃, such as, but not limited to, 210℃, 220℃, 230℃, 240℃, 250℃, 260℃, 270℃, 280℃, and 290℃.

[0052] In the above technical solution, the preferred processing time for the later stage is 1 to 5 hours, such as, but not limited to, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, etc.

[0053] The preparation method of the test block and the method of friction performance testing in this invention are as follows:

[0054] 1. Preparation of test blocks

[0055] The coating obtained in the specific embodiment of the present invention was sprayed onto a Q235 carbon steel plate with a length, width and height of 25×7×4mm using an air spray gun at a pressure of 0.24 bar. It was dried in an oven at 120℃ for 8 hours and then cured by heat treatment in an oven at 250℃ for 2 hours to obtain a solid lubricating coating. The solid lubricating coating with a thickness of 30±2μm was selected as the test block for friction performance testing.

[0056] 2. Friction performance test

[0057] 2.1 Coefficient of friction of the coating

[0058] The friction and wear tester was used to conduct the test at 25℃ according to the standard GB / T 12444-2006 using an M-2000 friction and wear tester. During the test, the friction coefficient data was recorded every 0.1 seconds. Data with an error greater than 6 standard deviations were removed, and the arithmetic mean of the remaining data was used as the friction coefficient of the sample. The test ring was a standard 36mm diameter GCr15 steel ring provided with the tester. The test load was 100N, and the test was conducted for 30 minutes under this load. The linear velocity of the steel ring was 0.42m / s.

[0059] 2.2 Coating Wear Rate

[0060] The wear volume and wear path of the test block were obtained by using an M-2000 friction and wear testing machine at 25℃ according to standard GB / T 12444-2006. The test ring was a standard 36mm diameter GCr15 steel ring provided with the testing machine. The test time was 30 minutes, and the linear velocity of the steel ring was 0.42m / s. The wear rate of the coating was then calculated using the following formula:

[0061] Ws = Vs / (L × F);

[0062] In the formula, Ws represents the wear rate (mm). 3 / (N·m)), Vs - wear volume (mm) 3 L - grinding distance (m), F - load (N);

[0063] Three parallel experiments were conducted, and the arithmetic mean was taken.

[0064] The present invention will now be described in detail through specific embodiments. Detailed Implementation

[0065]

Comparative Example 1

[0066] It has not undergone any modification treatment, specifically:

[0067] 1. Polyimide Synthesis

[0068] The synthesis method of polyimide was carried out according to the method disclosed in CN110713598A, specifically as follows:

[0069] p-Phenylenediamine was dissolved in N,N-dimethylacetamide. While maintaining the temperature at 25°C and stirring, pyromellitic dianhydride was slowly added, and the reaction was continued for 12 hours while maintaining the temperature and stirring to obtain a polyamic acid solution. Then, pyridine was added as an imidization accelerator and acetic anhydride as a chemical dehydrating agent, and the reaction was carried out at 40°C for 12 hours to obtain a crude polyimide solution. Next, while stirring, the crude polyimide solution was slowly added to an aqueous ethanol solution (the weight concentration of ethanol in the aqueous ethanol solution was 50%, and the weight ratio of the crude polyimide solution to the aqueous ethanol solution was 1:10). The mixture was filtered and dried at 90°C for 4 hours to obtain soluble polyimide powder.

[0070] The molar ratio of p-phenylenediamine: N,N-dimethylacetamide: pyridine dianhydride: acetic anhydride is 1:30:1.01:1:4.

[0071] 2. Coating preparation

[0072] Mix 508 parts by weight of graphite wet grinding slurry with 510 parts by weight of molybdenum disulfide wet grinding slurry to obtain mixture 1;

[0073] The coating is obtained by dissolving 250 parts by weight of the polyimide from Section 1 in Mixture I.

[0074] 3. Friction performance test

[0075] The coefficient of friction was measured to be 0.683, and the wear rate was 10.43 × 10⁻⁶. -6 mm 3 / (N·m).

[0076] [Comparative Example 2]

[0077] All polyimides are generated in situ.

[0078] 1. Polyimide Synthesis

[0079] The synthesis method of polyimide was carried out according to the method disclosed in CN110713598A, specifically as follows:

[0080] p-Phenylenediamine was dissolved in N,N-dimethylacetamide. While maintaining the temperature at 25°C and stirring, pyromellitic dianhydride was slowly added, and the reaction was continued for 12 hours while maintaining the temperature and stirring to obtain a polyamic acid solution. Then, pyridine was added as an imidization accelerator and acetic anhydride as a chemical dehydrating agent, and the reaction was carried out at 40°C for 12 hours to obtain a crude polyimide solution. Next, while stirring, the crude polyimide solution was slowly added to an aqueous ethanol solution (the weight concentration of ethanol in the aqueous ethanol solution was 50%, and the weight ratio of the crude polyimide solution to the aqueous ethanol solution was 1:10). The mixture was filtered and dried at 90°C for 4 hours to obtain soluble polyimide powder.

[0081] The molar ratio of p-phenylenediamine: N,N-dimethylacetamide: pyridine dianhydride: acetic anhydride is 1:30:1.01:1:4.

[0082] 2. Coating preparation

[0083] Mix 508 parts by weight of graphite wet grinding slurry with 510 parts by weight of molybdenum disulfide wet grinding slurry to obtain mixture 1;

[0084] p-phenylenediamine was dissolved in mixture I to obtain mixture 2; while stirring and maintaining the temperature of mixture 2 at 25°C, picrophthalic anhydride was slowly added, with a total weight of 250 parts of picrophthalic anhydride and p-phenylenediamine, and a molar ratio of picrophthalic anhydride to p-phenylenediamine of 1.01. Then, the mixture was modified for 12 hours under stirring and 25°C to obtain a coating.

[0085] 3. Friction performance test

[0086] The coefficient of friction was measured to be 0.611, and the wear rate was 9.64 × 10⁻⁶. -6 mm 3 / (N·m).

[0087] [Comparative Example 3]

[0088] First, molybdenum disulfide and graphite are modified, and then polyimide is added.

[0089] 1. Polyimide Synthesis

[0090] The synthesis method of polyimide was carried out according to the method disclosed in CN110713598A, specifically as follows:

[0091] p-Phenylenediamine was dissolved in N,N-dimethylacetamide. While maintaining the temperature at 25°C and stirring, pyromellitic dianhydride was slowly added, and the reaction was continued for 12 hours while maintaining the temperature and stirring to obtain a polyamic acid solution. Then, pyridine was added as an imidization accelerator and acetic anhydride as a chemical dehydrating agent, and the reaction was carried out at 40°C for 12 hours to obtain a crude polyimide solution. Next, while stirring, the crude polyimide solution was slowly added to an aqueous ethanol solution (the weight concentration of ethanol in the aqueous ethanol solution was 50%, and the weight ratio of the crude polyimide solution to the aqueous ethanol solution was 1:10). The mixture was filtered and dried at 90°C for 4 hours to obtain soluble polyimide powder.

[0092] The molar ratio of p-phenylenediamine: N,N-dimethylacetamide: pyridine dianhydride: acetic anhydride is 1:30:1.01:1:4.

[0093] 2. Coating preparation

[0094] Mix 508 parts by weight of graphite wet grinding slurry with 510 parts by weight of molybdenum disulfide wet grinding slurry to obtain mixture 1;

[0095] p-Phenylenediamine was dissolved in mixture I to obtain mixture 2;

[0096] While stirring and maintaining the temperature of mixture 2 at 25°C, picrophthalic dianhydride is slowly added. The total weight parts of picrophthalic dianhydride and p-phenylenediamine are 50 parts, and the molar ratio of picrophthalic dianhydride to p-phenylenediamine is 1.01. Then, the mixture is modified for 12 hours under stirring and 25°C. Finally, 200 parts by weight of polyimide from Section 1 are added to dissolve the polyimide, thus obtaining the coating.

[0097] 3. Friction performance test

[0098] The coefficient of friction was measured to be 0.457, and the wear rate was 9.12 × 10⁻⁶. -6 mm 3 / (N·m).

[0099]

Example 1

[0100] 1. Polyimide Synthesis

[0101] The synthesis method of polyimide was carried out according to the method disclosed in CN110713598A, specifically as follows:

[0102] p-Phenylenediamine was dissolved in N,N-dimethylacetamide. While maintaining the temperature at 25°C and stirring, pyromellitic dianhydride was slowly added, and the reaction was continued for 12 hours while maintaining the temperature and stirring to obtain a polyamic acid solution. Then, pyridine was added as an imidization accelerator and acetic anhydride as a chemical dehydrating agent, and the reaction was carried out at 40°C for 12 hours to obtain a crude polyimide solution. Next, while stirring, the crude polyimide solution was slowly added to an aqueous ethanol solution (the weight concentration of ethanol in the aqueous ethanol solution was 50%, and the weight ratio of the crude polyimide solution to the aqueous ethanol solution was 1:10). The mixture was filtered and dried at 90°C for 4 hours to obtain soluble polyimide powder.

[0103] The molar ratio of p-phenylenediamine: N,N-dimethylacetamide: pyridine dianhydride: acetic anhydride is 1:30:1.01:1:4.

[0104] 2. Coating preparation

[0105] Mix 508 parts by weight of graphite wet grinding slurry with 510 parts by weight of molybdenum disulfide wet grinding slurry to obtain mixture 1;

[0106] Dissolve 200 parts by weight of the polyimide and p-phenylenediamine from Section 1 in Mixture I to obtain Mixture 2;

[0107] While stirring and maintaining the temperature of mixture 2 at 25°C, picrophthalic anhydride is slowly added. The total weight of picrophthalic anhydride and p-phenylenediamine is 50 parts, and the molar ratio of picrophthalic anhydride to p-phenylenediamine is 1.01. Then, the mixture is modified for 12 hours under stirring and 25°C to obtain the coating.

[0108] 3. Friction performance test

[0109] The coefficient of friction was measured to be 0.167, and the wear rate was 7.44 × 10⁻⁶. -6 mm 3 / (N·m).

[0110]

Example 2

[0111] 1. Polyimide Synthesis

[0112] The synthesis method of polyimide was carried out according to the method disclosed in CN110713598A, specifically as follows:

[0113] Diaminodiphenyl ether (CAS101-80-4) was dissolved in N,N-dimethylacetamide. Under controlled temperature of 25°C and stirring, biphenyl ether dianhydride (CAS1823-59-2) was slowly added. The reaction was continued for 12 hours while maintaining the temperature and stirring to obtain a polyamic acid solution. Pyridine was then added as an imidization accelerator and acetic anhydride as a chemical dehydrating agent, and the reaction was carried out at 40°C for 12 hours to obtain a crude polyimide solution. Then, under stirring, the crude polyimide solution was slowly added to an aqueous ethanol solution (the weight concentration of ethanol in the aqueous ethanol solution was 50%, and the weight ratio of the crude polyimide solution to the aqueous ethanol solution was 1:10). The mixture was filtered and dried at 90°C for 4 hours to obtain soluble polyimide powder.

[0114] The molar ratio of diaminodiphenyl ether: N,N-dimethylacetamide: biphenyl ether dianhydride: pyridine: acetic anhydride is 1:30:1.01:1:4.

[0115] 2. Coating preparation

[0116] Mix 508 parts by weight of graphite wet grinding slurry with 510 parts by weight of molybdenum disulfide wet grinding slurry to obtain mixture 1;

[0117] Dissolve 200 parts by weight of the polyimide and p-phenylenediamine from Section 1 in Mixture I to obtain Mixture 2;

[0118] While stirring and maintaining the temperature of mixture 2 at 25°C, diphenyl ether dianhydride is slowly added. The total weight parts of diphenyl ether dianhydride and p-phenylenediamine are 50 parts, and the molar ratio of diphenyl ether dianhydride to p-phenylenediamine is 1.01. Then, the coating is obtained by modification treatment for 12 hours under stirring and 25°C.

[0119] 3. Friction performance test

[0120] The coefficient of friction was measured to be 0.148, and the wear rate was 6.64 × 10⁻⁶. -6 mm 3 / (N·m).

[0121]

Example 3

[0122] 1. Polyimide Synthesis

[0123] The synthesis method of polyimide was carried out according to the method disclosed in CN110713598A, specifically as follows:

[0124] Diaminodiphenyl ether (CAS101-80-4) was dissolved in N,N-dimethylacetamide. Under controlled temperature of 25°C and stirring, biphenyl ether dianhydride (CAS1823-59-2) was slowly added. The reaction was continued for 12 hours while maintaining the temperature and stirring to obtain a polyamic acid solution. Pyridine was then added as an imidization accelerator and acetic anhydride as a chemical dehydrating agent, and the reaction was carried out at 40°C for 12 hours to obtain a crude polyimide solution. Then, under stirring, the crude polyimide solution was slowly added to an aqueous ethanol solution (the weight concentration of ethanol in the aqueous ethanol solution was 50%, and the weight ratio of the crude polyimide solution to the aqueous ethanol solution was 1:10). The mixture was filtered and dried at 90°C for 4 hours to obtain soluble polyimide powder.

[0125] The molar ratio of diaminodiphenyl ether: N,N-dimethylacetamide: biphenyl ether dianhydride: pyridine: acetic anhydride is 1:30:1.01:1:4.

[0126] 2. Coating preparation

[0127] Mix 508 parts by weight of graphite wet grinding slurry with 510 parts by weight of molybdenum disulfide wet grinding slurry to obtain mixture 1;

[0128] Dissolve 200 parts by weight of the polyimide and diaminodiphenyl ether from Section 1 in Mixture I to obtain Mixture 2;

[0129] While stirring and maintaining the temperature of mixture 2 at 25°C, diphenyl ether dianhydride is slowly added. The total weight parts of diphenyl ether dianhydride and diaminodiphenyl ether are 50 parts, and the molar ratio of diphenyl ether dianhydride to diaminodiphenyl ether is 1.01. Then, the coating is obtained by modification treatment for 12 hours under stirring and 25°C.

[0130] 3. Friction performance test

[0131] The coefficient of friction was measured to be 0.124, and the wear rate was 6.45 × 10⁻⁶. -6 mm 3 / (N·m).

[0132]

Example 4

[0133] 1. Polyimide Synthesis

[0134] The synthesis method of polyimide was carried out according to the method disclosed in CN110713598A, specifically as follows:

[0135] Diaminodiphenyl ether (CAS101-80-4) was dissolved in N,N-dimethylacetamide. Under controlled temperature of 25°C and stirring, biphenyl ether dianhydride (CAS1823-59-2) was slowly added. The reaction was continued for 12 hours while maintaining the temperature and stirring to obtain a polyamic acid solution. Pyridine was then added as an imidization accelerator and acetic anhydride as a chemical dehydrating agent, and the reaction was carried out at 40°C for 12 hours to obtain a crude polyimide solution. Then, under stirring, the crude polyimide solution was slowly added to an aqueous ethanol solution (the weight concentration of ethanol in the aqueous ethanol solution was 50%, and the weight ratio of the crude polyimide solution to the aqueous ethanol solution was 1:10). The mixture was filtered and dried at 90°C for 4 hours to obtain soluble polyimide powder.

[0136] The molar ratio of diaminodiphenyl ether: N,N-dimethylacetamide: biphenyl ether dianhydride: pyridine: acetic anhydride is 1:30:1.01:1:4.

[0137] 2. Coating preparation

[0138] Mix 508 parts by weight of graphite wet grinding slurry with 510 parts by weight of molybdenum disulfide wet grinding slurry to obtain mixture 1;

[0139] Dissolve 200 parts by weight of polyimide, p-phenylenediamine and diaminodiphenyl ether from Section 1 in mixture I to obtain mixture 2;

[0140] While stirring and maintaining the temperature of mixture 2 at 25°C, diphenyl ether dianhydride is slowly added. The total weight parts of diphenyl ether dianhydride, p-phenylenediamine, and diaminodiphenyl ether are 50 parts. The molar ratio of diphenyl ether dianhydride to (p-phenylenediamine + diaminodiphenyl ether) is 1.01, and the molar ratio of diaminodiphenyl ether to p-phenylenediamine is 2.0. Then, the coating is obtained by modification treatment for 12 hours under stirring and 25°C.

[0141] 3. Friction performance test

[0142] The coefficient of friction was measured to be 0.054, and the wear rate was 5.83 × 10⁻⁶. -6 mm 3 / (N·m).

[0143]

Example 5

[0144] 1. Polyimide Synthesis

[0145] The synthesis method of polyimide was carried out according to the method disclosed in CN110713598A, specifically as follows:

[0146] Diaminodiphenyl ether (CAS101-80-4) was dissolved in N,N-dimethylacetamide. Under controlled temperature of 25°C and stirring, biphenyl ether dianhydride (CAS1823-59-2) was slowly added. The reaction was continued for 12 hours while maintaining the temperature and stirring to obtain a polyamic acid solution. Pyridine was then added as an imidization accelerator and acetic anhydride as a chemical dehydrating agent, and the reaction was carried out at 40°C for 12 hours to obtain a crude polyimide solution. Then, under stirring, the crude polyimide solution was slowly added to an aqueous ethanol solution (the weight concentration of ethanol in the aqueous ethanol solution was 50%, and the weight ratio of the crude polyimide solution to the aqueous ethanol solution was 1:10). The mixture was filtered and dried at 90°C for 4 hours to obtain soluble polyimide powder.

[0147] The molar ratio of diaminodiphenyl ether: N,N-dimethylacetamide: biphenyl ether dianhydride: pyridine: acetic anhydride is 1:30:1.01:1:4.

[0148] 2. Coating preparation

[0149] Mix 508 parts by weight of graphite wet grinding slurry with 510 parts by weight of molybdenum disulfide wet grinding slurry to obtain mixture 1;

[0150] Dissolve 200 parts by weight of polyimide, p-phenylenediamine and diaminodiphenyl ether from Section 1 in mixture I to obtain mixture 2;

[0151] While stirring and maintaining the temperature of mixture 2 at 25°C, diphenyl ether dianhydride is slowly added. The total weight parts of diphenyl ether dianhydride, p-phenylenediamine, and diaminodiphenyl ether are 50 parts. The molar ratio of diphenyl ether dianhydride to (p-phenylenediamine + diaminodiphenyl ether) is 1.01, and the molar ratio of diaminodiphenyl ether to p-phenylenediamine is 6.0. Then, the coating is obtained by modification treatment for 12 hours under stirring and 25°C.

[0152] 3. Friction performance test

[0153] The coefficient of friction was measured to be 0.031, and the wear rate was 4.96 × 10⁻⁶. -6 mm 3 / (N·m).

[0154]

Example 6

[0155] 1. Polyimide Synthesis

[0156] The synthesis method of polyimide was carried out according to the method disclosed in CN110713598A, specifically as follows:

[0157] Diaminodiphenyl ether (CAS101-80-4) was dissolved in N,N-dimethylacetamide. Under controlled temperature of 25°C and stirring, biphenyl ether dianhydride (CAS1823-59-2) was slowly added. The reaction was continued for 12 hours while maintaining the temperature and stirring to obtain a polyamic acid solution. Pyridine was then added as an imidization accelerator and acetic anhydride as a chemical dehydrating agent, and the reaction was carried out at 40°C for 12 hours to obtain a crude polyimide solution. Then, under stirring, the crude polyimide solution was slowly added to an aqueous ethanol solution (the weight concentration of ethanol in the aqueous ethanol solution was 50%, and the weight ratio of the crude polyimide solution to the aqueous ethanol solution was 1:10). The mixture was filtered and dried at 90°C for 4 hours to obtain soluble polyimide powder.

[0158] The molar ratio of diaminodiphenyl ether: N,N-dimethylacetamide: biphenyl ether dianhydride: pyridine: acetic anhydride is 1:30:1.01:1:4.

[0159] 2. Coating preparation

[0160] Mix 508 parts by weight of graphite wet grinding slurry with 510 parts by weight of molybdenum disulfide wet grinding slurry to obtain mixture 1;

[0161] Dissolve 200 parts by weight of polyimide, p-phenylenediamine and diaminodiphenyl ether from Section 1 in mixture I to obtain mixture 2;

[0162] While stirring and maintaining the temperature of mixture 2 at 25°C, diphenyl ether dianhydride is slowly added. The total weight parts of diphenyl ether dianhydride, p-phenylenediamine, and diaminodiphenyl ether are 50 parts. The molar ratio of diphenyl ether dianhydride to (p-phenylenediamine + diaminodiphenyl ether) is 1.01, and the molar ratio of diaminodiphenyl ether to p-phenylenediamine is 9.0. Then, the coating is obtained by modification treatment for 12 hours under stirring and 25°C.

[0163] 3. Friction performance test

[0164] The coefficient of friction was measured to be 0.046, and the wear rate was 5.69 × 10⁻⁶. -6 mm 3 / (N·m).

Claims

1. A method for preparing a coating for manufacturing a high-temperature resistant solid lubricant coating, comprising: In a solvent, a mixture comprising the following components is modified with a polyimide precursor: polyimide and solid lubricant; The solvents mentioned include aprotic polar solvents; the solid lubricants include molybdenum disulfide and graphite; Polyimide precursors include: (1) Aromatic dianhydrides; (2) Aromatic diamines; Aromatic diamines include both 4,4'-diaminodiphenyl ether and p-phenylenediamine; the molar ratio of 4,4'-diaminodiphenyl ether to p-phenylenediamine is 2 to 9.

2. The preparation method according to claim 1, characterized in that: The aprotic polar solvent is at least one of dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone.

3. The preparation method according to claim 1, characterized in that: The molar ratio of component (1) to component (2) is 0.90~1.

10.

4. The preparation method according to claim 1, characterized in that: By weight, The polyimide precursor is 30-60 parts; The polyimide is in the form of 50-300 parts; The molybdenum disulfide is 1 to 20 parts; The amount of graphite is 1 to 10 parts; The aprotic polar solvent is 1000 parts.

5. The preparation method according to claim 1, characterized in that: The modification treatment temperature is 5~30℃.

6. The preparation method according to claim 1, characterized in that: The modification treatment takes 1 to 10 hours.

7. The coating obtained by the preparation method according to any one of claims 1 to 6.

8. The application of the coating of claim 7 in the manufacture of high-temperature resistant solid lubricating coatings.

9. A method for manufacturing a high-temperature resistant solid lubricant coating, comprising: (i) Applying the coating of claim 7 to the surface of the material to be coated to obtain a precursor coating; (ii) Heat treatment transforms the precursor coating into a high-temperature resistant solid lubricant coating.

10. The manufacturing method according to claim 9, characterized in that: Step (ii) heat treatment includes at least two stages: Previous stage The solvent in the precursor coating is removed below the boiling point of the solvent to obtain a cured intermediate coating; Later stage The high-temperature resistant solid lubricating coating is obtained by curing the intermediate coating.

11. The manufacturing method according to claim 10, characterized in that: The temperature t of the previous stage of treatment conforms to t = aB, where B is the boiling point of the solvent and a is 0.4~0.

9.

12. The manufacturing method according to claim 10, characterized in that: The initial processing time is 5 to 10 hours.

13. The manufacturing method according to claim 10, characterized in that: The temperature for the later stage of processing is 200~300℃.

14. The manufacturing method according to claim 10, characterized in that: The subsequent processing time is 1 to 5 hours.