Preparation method of organic high-temperature-resistant abradable seal coating material

Abstract

The application discloses a preparation method of an organic high-temperature-resistant abradable seal coating material, and belongs to the technical field of composite materials. The method comprises the following steps: (1) preparing a solvent-free silicon resin by a co-hydrolysis condensation reaction with methyl triethoxysilane, methyl phenyl diethoxysilane, phenyl trimethoxysilane and gamma-(2,3-epoxypropoxy) propyl trimethoxysilane as necessary monomers; (2) mixing the solvent-free silicon resin with graphite, basalt fiber, serpentine fiber and carbon fiber, and stirring and grinding in a banbury mixer to obtain putty-like abradable seal coating; and (3) coating the coating on a substrate in a smearing manner, and curing at high temperature to obtain the organic high-temperature-resistant abradable seal coating. The coating prepared by the method has no cracking, falling or pulverization phenomenon after being kept at 350 DEG C for 100 hours, has a room-temperature shear strength of 8-12 MPa, a room-temperature tensile strength of 6-8 MPa, and a coating density of 1.30-1.65 g / cm 3 The method is simple, the coating is well combined with a resin-based composite material fan case, has excellent temperature resistance and mechanical properties, and is suitable for the field of aerospace.

Description

Technical Field

[0001] This invention belongs to the field of composite material technology, specifically relating to an organic high-temperature wear-resistant sealing coating material and its preparation method, which is particularly suitable for wear-resistant sealing coatings for resin-based composite fan casings of aero-engines. Background Technology

[0002] As aero-engines develop towards higher power, higher thrust-to-weight ratio, lighter weight, and integrated aerospace capabilities, higher demands are placed on engine efficiency and reliability. As a critical structural component of the engine, the fan casing increasingly utilizes high-strength, high-temperature-resistant resin-based composite materials (such as polyimide / carbon fiber composites) to replace traditional metal materials, achieving significant weight reduction. Correspondingly, higher requirements are placed on the molding method, heat resistance, bonding strength, and safety of the matching wear-resistant sealing coating.

[0003] Abrasion-resistant sealing coatings are sacrificial coatings installed between rotor blades and the casing. They are designed to be preferentially worn away during radial abrasion between the blades and the casing, thereby protecting the blades, reducing tip clearance, and improving engine efficiency. Currently, abrasion-resistant sealing coatings widely used in aero-engines are mostly prepared using thermal spraying techniques, such as plasma spraying and flame spraying. The coating materials are mostly metal-based, ceramic-based, or metal-ceramic composite systems. However, the high temperature (typically >1000℃) and high impact characteristics of thermal spraying processes make it extremely easy to cause thermal damage to the composite substrate, reduced interfacial bonding strength, or even substrate destruction when directly applied to resin-based composite fan casings. Therefore, traditional thermal spraying abrasion-resistant sealing coating technology is difficult to match with resin-based composite casings.

[0004] To overcome the aforementioned problems, organic-based abrasive sealing coatings have gradually attracted attention. For example, Chinese patent application CN102051118A discloses a cyclosilicone resin sealing coating, using cyclosilicone resin as a binder and graphite and other materials as fillers, for use in industrial centrifugal compressors. However, this solution does not involve a fiber-reinforced system, and its mechanical properties and temperature resistance are limited, making it difficult to meet the requirements of aero-engines for higher operating temperatures (such as 350°C) and higher bonding strength. In addition, related research papers (such as "Materials Protection" 2021, No. 2) disclose sealing coatings based on methylphenyl silicone resin, but this coating is a metal-free filler system, with an operating temperature limited to around 300°C, and does not disclose compatibility data with resin-based composite substrates.

[0005] In summary, the existing technology still has the following shortcomings: First, there is a lack of organic wearable sealing coating preparation methods that can be well matched with resin-based composite fan casings (low stress, high bonding strength); second, the temperature resistance (below 300℃) and mechanical properties (shear strength, tensile strength) of existing silicone resin-based sealing coatings cannot meet the 350℃ requirements of the new generation of aero engines; third, there is no technical solution that uses multiple fibers for synergistic reinforcement, epoxy silane modified silicone resin and applied to wearable sealing coatings for resin-based composite casings.

[0006] Therefore, developing an organic sealing coating and its preparation method that can be matched with resin-based composite fan casings, has high bonding strength, excellent temperature resistance (long-term use at 350℃), and good wear resistance has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0007] This invention provides a method for preparing an organic high-temperature wear-resistant sealing coating material and the resulting coating. It aims to address the technical problems in the prior art, such as the inapplicability of traditional thermal spray wear-resistant sealing coatings to resin-based composite fan casings due to high temperature and impact, and the insufficient temperature resistance (typically below 300℃), low mechanical properties, and lack of good compatibility with composite material substrates of existing silicone resin-based sealing coatings.

[0008] The coating prepared by this invention has high bonding strength (room temperature shear strength 8-12 MPa), excellent temperature resistance (no cracking / peeling / powdering after 100 h at 350℃), and good abrasion resistance, which can meet the stringent requirements of the next generation of aero-engines for sealing coatings of resin-based composite material fan casings.

[0009] To achieve the above-mentioned objectives, the present invention provides the following technical solution: A method for preparing an organic high-temperature resistant wear-resistant sealing coating material includes the following steps: (1) Preparation of solvent-free silicone resin: Solvent-free silicone resin is prepared by co-hydrolysis condensation reaction using alkoxysilanes including methyltriethoxysilane, methylphenyldiethoxysilane, phenyltrimethoxysilane and γ-(2,3-epoxypropoxy)propyltrimethoxysilane as necessary monomers.

[0010] Specifically, using toluene and anhydrous ethanol as solvents, the above four alkoxysilane monomers are added to obtain mixed solution 1; mixed solution 1 is heated to 60-70℃, and then phosphoric acid aqueous solution is added dropwise to obtain mixed solution 2; mixed solution 2 is refluxed at 60-70℃ for 7 hours, then heated to 130-150℃ and refluxed for 1.5 hours, and finally distilled at 130-150℃ to obtain solvent-free liquid silicone resin.

[0011] The preferred amounts of each monomer and solvent, by weight, are as follows: 40-60 parts of methyltriethoxysilane, 50-60 parts of methylphenyldiethoxysilane, 10-30 parts of phenyltrimethoxysilane, 5-10 parts of γ-(2,3-epoxypropoxy)propyltrimethoxysilane; 80-100 parts of toluene, 80-100 parts of anhydrous ethanol; and 70-100 parts of the phosphoric acid aqueous solution, which consists of 0.5-1.0 parts of phosphoric acid and 70-90 parts of deionized water.

[0012] (2) Preparation of abrasive sealant: The solvent-free silicone resin prepared in step (1) is mixed with graphite, basalt fiber, serpentine fiber and carbon fiber, and then stirred and ground in a mixer to obtain a uniformly mixed putty-like abrasive sealant.

[0013] Specifically, graphite, basalt fiber, serpentine fiber, and carbon fiber are added to the solvent-free liquid silicone resin for preliminary mixing, and then the resulting mixture is transferred to a mixer for stirring and grinding for 2-6 hours to obtain the abrasive sealing coating.

[0014] The preferred amounts of each component by weight are: 80-100 parts of solvent-free liquid silicone resin, 20-40 parts of graphite with a particle size of 300-350 mesh, 10-15 parts of basalt fiber with a length of 1-3 mm, 5-10 parts of serpentine fiber with a length of 1-3 mm, and 2-5 parts of carbon fiber with a length of 1-2 mm.

[0015] (3) Preparation and curing of coating: The abrasive sealing coating obtained in step (2) is applied to the substrate by smearing, and the organic high temperature abrasive sealing coating is obtained after high temperature curing.

[0016] The preferred heat treatment process for high-temperature curing is as follows: pretreatment at 80-110℃ for 1-2 hours, followed by treatment at 160-200℃ for 2-4 hours, with a heating rate ≤3℃ / min; the typical thickness of the coating is 2-5mm.

[0017] The organic high-temperature wear-resistant sealing coating prepared by the above method has a room temperature shear strength of 8-12 MPa, a room temperature tensile strength of 6-8 MPa, and a coating density of 1.30-1.65 g / cm3. After being kept at 350℃ for 100 hours, the coating showed no cracks, peeling, or powdering.

[0018] Compared with existing technologies, the present invention has the following superior technical effects: 1. This invention uses a coating method to form the coating, avoiding the high temperature and high impact process of thermal spraying technology. It will not cause thermal damage or interface destruction to the resin-based composite material fan casing. The coating has high bonding strength with the composite material substrate (room temperature shear strength 5-7MPa, tested on polyimide / carbon fiber composite material specimens), good processing performance, and will not fall off during machining.

[0019] 2. This invention uses γ-(2,3-epoxypropoxy)propyltrimethoxysilane to copolymerize and modify silicone resin, and selects basalt fiber, serpentine fiber, carbon fiber and other multi-fiber synergistic reinforcement. The prepared coating can be used for a long time at 350℃ (the coating does not crack, peel or powder after 100h of heat preservation at 350℃), which is far beyond the operating temperature of existing organosilicon sealing coatings, which is usually no more than 300℃, and meets the high temperature requirements of the new generation of aero engines.

[0020] 3. The prepared coating exhibits a room temperature shear strength of 8-12 MPa (stainless steel substrate), a room temperature tensile strength of 6-8 MPa, and a tensile strength of 1.5-2.5 MPa at 350℃, demonstrating excellent high-temperature strength retention. The Shore D hardness is 60-70, balancing abrasion resistance and structural integrity.

[0021] 4. This invention creatively combines basalt fiber (high temperature resistance, reinforcement), serpentine fiber (lubrication, wear resistance), carbon fiber (high strength, electrical and thermal conductivity) with graphite (solid lubricant). After being fully ground and dispersed in an internal mixer, a three-dimensional network reinforcement structure is formed, which not only improves the mechanical properties and thermal stability of the coating, but also ensures good wear resistance.

[0022] 5. The resulting abrasive sealing coating is a uniform paste in the form of putty, free of foreign impurities, and can be applied directly without solvent dilution. It is environmentally friendly and suitable for industrial production.

[0023] In summary, this invention provides an organic high-temperature wear-resistant sealing coating and its preparation method that can be well matched with resin-based composite fan casings, has high bonding strength, excellent temperature resistance and wear resistance, and has significant technological advancement and industrial application value. Attached Figure Description

[0024] Figure 1 This is a scanning electron microscope (SEM) image of the organic high-temperature resistant wear-resistant sealing coating of the present invention.

[0025] Figure 2 This is an energy dispersive spectroscopy (EDS) diagram of the organic high-temperature wear-resistant sealing coating of the present invention.

[0026] Figure 3The images show photographs and cross-sectional SEM images of the shear strength test specimens of the organic high-temperature wear-resistant sealing coating of the present invention on a polyimide / carbon fiber composite substrate; wherein (a) is the specimen before testing, (b) is the specimen after testing, and (c) is the cross-sectional SEM image of the shear strength test specimen.

[0027] Figure 4 These are comparative photos of the organic high-temperature wear-resistant sealing coating of the present invention before and after heat aging at 350°C for 100 hours; where (a) is before heat aging, and (b) and (c) are after heat aging.

[0028] Figure 5 The images show photographs and SEM images of the test surfaces of the organic high-temperature wear-resistant sealing coating of the present invention after the bonding strength test; where (a) and (b) are photographs after the test, and (c) is an SEM image of the test surface.

[0029] Figure 6 This is a shear strength-displacement curve of the organic high-temperature wear-resistant sealing coating of the present invention on stainless steel substrates and polyimide / carbon fiber composite substrates. Detailed Implementation

[0030] The present invention will be further described below through specific embodiments. These embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit its scope of protection. All equivalent substitutions or modifications made based on the technical concept of the present invention fall within the protection scope of the present invention.

[0031] 1. Main raw material sources (example): Methyltriethoxysilane, methylphenyldiethoxysilane, phenyltrimethoxysilane: Commercially available, purity ≥98%; γ-(2,3-epoxypropoxy)propyltrimethoxysilane: commercially available, purity ≥97%; Graphite: 300-350 mesh, commercially available; Basalt fiber: 1-3mm in length, commercially available; Serpentine fiber: 1-3mm in length, commercially available; Carbon fiber: 1-2mm in length, commercially available.

[0032] 2. Performance testing methods: Shear strength: According to GB / T 7124, a microcomputer-controlled universal testing machine was used to conduct single lap joint tests on austenitic stainless steel specimens and polyimide / carbon fiber composite specimens, respectively, with a loading rate of 1 mm / min.

[0033] Tensile strength: Using No. 45 steel test bars (diameter 25mm, length 100mm, with threads on the outer diameter), the coating was applied to the end faces of the two test bars and then bonded and cured. Tensile test was performed according to GB / T 7124 at a rate of 1mm / min.

[0034] Coating density: determined according to GB / T 4472-2011, using the specific gravity bottle method or the liquid displacement method.

[0035] Shore D hardness: determined at 24℃ according to GB / T 2411-2008.

[0036] Temperature resistance: Place the coating in a 350℃ oven for 100 hours, remove it and cool it to room temperature, then observe whether the coating has cracks, peeling or powdering.

[0037] Example 1 Synthesis of solvent-free liquid silicone resin: 80.00 g toluene, 80.00 g anhydrous ethanol, 40.00 g methyltriethoxysilane, 50.00 g methylphenyldiethoxysilane, 10.00 g phenyltrimethoxysilane, and 5.00 g γ-(2,3-epoxypropoxy)propyltrimethoxysilane were added to a three-necked flask to obtain mixed solution 1, which was then mechanically stirred. Mixed solution 1 was heated to 60-70°C, and then 70.50 g of phosphoric acid aqueous solution (composed of 0.50 g phosphoric acid and 70.00 g deionized water) was added dropwise to mixed solution 1 to obtain mixed solution 2. Mixed solution 2 was refluxed at 60-70°C for 7 h, then heated to 130-150°C and refluxed for 1.5 h. Finally, mixed solution 2 was distilled at 130-150°C to obtain 57.75 g of solvent-free liquid silicone resin.

[0038] Preparation of abrasive sealing coating 1: 10.00g graphite, 5.00g basalt fiber, 2.50g serpentine fiber and 1.00g carbon fiber were added to 40.00g solvent-free liquid silicone resin for preliminary mixing. Then the mixture was transferred to a mixer and stirred for 2.50h to obtain abrasive sealing coating.

[0039] Preparation of an organic high-temperature resistant abrasive sealing coating: 1. The abrasive sealing coating was applied to the substrate, pretreated at 100℃ for 2 hours, then treated at 200℃ for 4 hours at a heating rate of 3℃ / min, and cured at high temperature to obtain the organic high-temperature resistant abrasive sealing coating. After curing, the coating exhibited a shear strength of 8.25 MPa, a tensile strength of 6.50 MPa, and a density of 1.35 g / cm³. 3 Other properties meet the aforementioned main performance indicators of the material.

[0040] Preparation of abrasive sealing coating 2: 15.00g graphite, 5.00g basalt fiber, 2.50g serpentine fiber and 2.00g carbon fiber were added to 40.00g solvent-free liquid silicone resin for preliminary mixing. Then the mixture was transferred to a mixer and stirred for 2.50h to obtain abrasive sealing coating.

[0041] Preparation of Organic High-Temperature Resistant Abrasive Sealing Coating 2: The abrasive sealing coating was applied to the substrate, pretreated at 100℃ for 2 hours, treated at 200℃ for 4 hours, with a heating rate of 3℃ / min, and cured at high temperature to obtain the organic high-temperature resistant abrasive sealing coating. After curing, the coating exhibited a shear strength of 8.50 MPa, a tensile strength of 6.60 MPa, and a density of 1.38 g / cm³. 3 Other properties meet the aforementioned main performance indicators of the material.

[0042] Preparation of abrasive sealing coating 3: 20.00g graphite, 5.00g basalt fiber, 3.00g serpentine fiber and 2.00g carbon fiber were added to 40.00g solvent-free liquid silicone resin for preliminary mixing. Then the mixture was transferred to a mixer and stirred for 3.00h to obtain abrasive sealing coating.

[0043] Preparation of an organic high-temperature resistant abrasive sealing coating: The abrasive sealing coating was applied to a substrate, pretreated at 100℃ for 2 hours, then treated at 200℃ for 4 hours at a heating rate of 3℃ / min, and cured at high temperature to obtain the organic high-temperature resistant abrasive sealing coating. After curing, the coating exhibited a shear strength of 9.00 MPa, a tensile strength of 7.10 MPa, and a density of 1.40 g / cm³. 3 Other properties meet the aforementioned main performance indicators of the material.

[0044] Example 2 Synthesis of solvent-free liquid silicone resin: 90.00 g toluene, 90.00 g anhydrous ethanol, 40.00 g methyltriethoxysilane, 55.00 g methylphenyldiethoxysilane, 25.00 g phenyltrimethoxysilane, and 10.00 g γ-(2,3-epoxypropoxy)propyltrimethoxysilane were added to a three-necked flask to obtain mixed solution 1, which was then mechanically stirred. Mixed solution 1 was heated to 60-70°C, and then 80.00 g of phosphoric acid aqueous solution (composed of 0.80 g phosphoric acid and 79.20 g deionized water) was added dropwise to mixed solution 1 to obtain mixed solution 2. Mixed solution 2 was refluxed at 60-70°C for 7 h, then heated to 130-150°C and refluxed for 1.5 h. Finally, mixed solution 2 was distilled at 130-150°C to obtain 72.00 g of solvent-free liquid silicone resin.

[0045] Preparation of abrasive sealing coating 1: 10.00g graphite, 5.00g basalt fiber, 2.50g serpentine fiber and 1.00g carbon fiber were added to 40.00g solvent-free liquid silicone resin for preliminary mixing. Then the mixture was transferred to a mixer and stirred for 2.50h to obtain abrasive sealing coating.

[0046] Preparation of an organic high-temperature resistant abrasive sealing coating: 1. The abrasive sealing coating was applied to the substrate, pretreated at 100℃ for 2 hours, then treated at 200℃ for 4 hours at a heating rate of 3℃ / min, and cured at high temperature to obtain the organic high-temperature resistant abrasive sealing coating. After curing, the coating exhibited a shear strength of 9.80 MPa, a tensile strength of 7.50 MPa, and a density of 1.36 g / cm³. 3 Other properties meet the aforementioned main performance indicators of the material.

[0047] Preparation of abrasive sealing coating 2: 15.00g graphite, 5.00g basalt fiber, 2.50g serpentine fiber and 2.00g carbon fiber were added to 40.00g solvent-free liquid silicone resin for preliminary mixing. Then the mixture was transferred to a mixer and stirred for 2.50h to obtain abrasive sealing coating.

[0048] Preparation of Organic High-Temperature Resistant Abrasion-Resistant Sealing Coating 2: The abrasion-resistant sealing coating was applied to the substrate, pretreated at 100℃ for 2 hours, treated at 200℃ for 4 hours, with a heating rate of 3℃ / min, and cured at high temperature to obtain the organic high-temperature resistant abrasion-resistant sealing coating. After curing, the coating exhibited a shear strength of 10.25 MPa, a tensile strength of 7.80 MPa, and a density of 1.40 g / cm³. 3 Other properties meet the aforementioned main performance indicators of the material.

[0049] Preparation of abrasive sealing coating 3: 20.00g graphite, 5.00g basalt fiber, 3.00g serpentine fiber and 2.00g carbon fiber were added to 40.00g solvent-free liquid silicone resin for preliminary mixing. Then the mixture was transferred to a mixer and stirred for 3.00h to obtain abrasive sealing coating.

[0050] Preparation of an organic high-temperature resistant abrasive sealing coating: The abrasive sealing coating was applied to the substrate, pretreated at 100℃ for 2 hours, then treated at 200℃ for 4 hours at a heating rate of 3℃ / min, and cured at high temperature to obtain the organic high-temperature resistant abrasive sealing coating. After curing, the coating exhibited a shear strength of 10.20 MPa, a tensile strength of 7.78 MPa, and a density of 1.41 g / cm³. 3 Other properties meet the aforementioned main performance indicators of the material.

[0051] Example 3 Synthesis of solvent-free liquid silicone resin: 95.00 g toluene, 95.00 g anhydrous ethanol, 50.00 g methyltriethoxysilane, 50.00 g methylphenyldiethoxysilane, 25.00 g phenyltrimethoxysilane, and 8.00 g γ-(2,3-epoxypropoxy)propyltrimethoxysilane were added to a three-necked flask to obtain mixed solution 1, which was then mechanically stirred. Mixed solution 1 was heated to 60-70°C, and then 85.00 g of phosphoric acid aqueous solution (composed of 0.85 g phosphoric acid and 84.15 g deionized water) was added dropwise to mixed solution 1 to obtain mixed solution 2. Mixed solution 2 was refluxed at 60-70°C for 7 h, then heated to 130-150°C and refluxed for 1.5 h. Finally, mixed solution 2 was distilled at 130-150°C to obtain 75.00 g of solvent-free liquid silicone resin.

[0052] Preparation of abrasive sealing coating 1: 10.00g graphite, 5.00g basalt fiber, 2.50g serpentine fiber and 1.00g carbon fiber were added to 40.00g solvent-free liquid silicone resin for preliminary mixing. Then the mixture was transferred to a mixer and stirred for 2.50h to obtain abrasive sealing coating.

[0053] Preparation of an organic high-temperature resistant abrasive sealing coating: 1. The abrasive sealing coating was applied to the substrate, pretreated at 100℃ for 2 hours, then treated at 200℃ for 4 hours at a heating rate of 3℃ / min, and cured at high temperature to obtain the organic high-temperature resistant abrasive sealing coating. After curing, the coating exhibited a shear strength of 10.00 MPa, a tensile strength of 7.60 MPa, and a density of 1.38 g / cm³. 3 Other properties meet the aforementioned main performance indicators of the material.

[0054] Preparation of abrasive sealing coating 2: 15.00g graphite, 5.00g basalt fiber, 2.50g serpentine fiber and 2.00g carbon fiber were added to 40.00g solvent-free liquid silicone resin for preliminary mixing. Then the mixture was transferred to a mixer and stirred for 2.50h to obtain abrasive sealing coating.

[0055] Preparation of Organic High-Temperature Resistant Abrasive Sealing Coating 2: The abrasive sealing coating was applied to the substrate, pretreated at 100℃ for 2 hours, treated at 200℃ for 4 hours, with a heating rate of 3℃ / min, and cured at high temperature to obtain the organic high-temperature resistant abrasive sealing coating. After curing, the coating exhibited a shear strength of 10.20 MPa, a tensile strength of 7.95 MPa, and a density of 1.40 g / cm³. 3 Other properties meet the aforementioned main performance indicators of the material.

[0056] Preparation of abrasive sealing coating 3: 20.00g graphite, 5.00g basalt fiber, 3.00g serpentine fiber and 2.00g carbon fiber were added to 40.00g solvent-free liquid silicone resin for preliminary mixing. Then the mixture was transferred to a mixer and stirred for 3.00h to obtain abrasive sealing coating.

[0057] Preparation of an organic high-temperature resistant abrasive sealing coating: The abrasive sealing coating was applied to the substrate, pretreated at 100℃ for 2 hours, then treated at 200℃ for 4 hours at a heating rate of 3℃ / min, and cured at high temperature to obtain the organic high-temperature resistant abrasive sealing coating. After curing, the coating exhibited a shear strength of 10.50 MPa, a tensile strength of 7.80 MPa, and a density of 1.41 g / cm³. 3 Other properties meet the aforementioned main performance indicators of the material.

[0058] Example 4 Synthesis of solvent-free liquid silicone resin: In a three-necked flask, add 100.00 g toluene, 100.00 g anhydrous ethanol, 55.00 g methyltriethoxysilane, 60.00 g methylphenyldiethoxysilane, 30.00 g phenyltrimethoxysilane, and 10.00 g γ-(2,3-epoxypropoxy)propyltrimethoxysilane to obtain mixed solution 1, and start mechanical stirring. Heat mixed solution 1 to 60-70℃, then add 100.00 g of phosphoric acid aqueous solution (composed of 1.00 g phosphoric acid and 99.00 g deionized water) dropwise to obtain mixed solution 2. Reflux mixed solution 2 at 60-70℃ for 7 h, then reflux at 130-150℃ for 1.5 h. Finally, distill mixed solution 2 at 130-150℃ to obtain 88.00 g of solvent-free liquid silicone resin.

[0059] Preparation of abrasive sealing coating 1: 10.00g graphite, 5.00g basalt fiber, 2.50g serpentine fiber and 1.00g carbon fiber were added to 40.00g solvent-free liquid silicone resin for preliminary mixing. Then the mixture was transferred to a mixer and stirred for 2.50h to obtain abrasive sealing coating.

[0060] Preparation of an organic high-temperature resistant abrasive sealing coating: 1. The abrasive sealing coating was applied to the substrate, pretreated at 100℃ for 2 hours, then treated at 200℃ for 4 hours at a heating rate of 3℃ / min, and cured at high temperature to obtain the organic high-temperature resistant abrasive sealing coating. After curing, the coating exhibited a shear strength of 11.20 MPa, a tensile strength of 7.80 MPa, and a density of 1.40 g / cm³. 3 Other properties meet the aforementioned main performance indicators of the material.

[0061] Preparation of abrasive sealing coating 2: 15.00g graphite, 5.00g basalt fiber, 2.50g serpentine fiber and 2.00g carbon fiber were added to 40.00g solvent-free liquid silicone resin for preliminary mixing. Then the mixture was transferred to a mixer and stirred for 2.50h to obtain abrasive sealing coating.

[0062] Preparation of Organic High-Temperature Resistant Abrasive Sealing Coating 2: The abrasive sealing coating was applied to the substrate, pretreated at 100℃ for 2 hours, then treated at 200℃ for 4 hours at a heating rate of 3℃ / min, and cured at high temperature to obtain the organic high-temperature resistant abrasive sealing coating. After curing, the coating exhibited a shear strength of 11.10 MPa, a tensile strength of 7.90 MPa, and a density of 1.45 g / cm³. 3 Other properties meet the aforementioned main performance indicators of the material.

[0063] Preparation of abrasive sealing coating 3: 20.00g graphite, 5.00g basalt fiber, 3.00g serpentine fiber and 2.00g carbon fiber were added to 40.00g solvent-free liquid silicone resin for preliminary mixing. Then the mixture was transferred to a mixer and stirred for 3.00h to obtain abrasive sealing coating.

[0064] Preparation of an organic high-temperature resistant abrasive sealing coating: The abrasive sealing coating was applied to the substrate, pretreated at 100℃ for 2 hours, then treated at 200℃ for 4 hours at a heating rate of 3℃ / min, and cured at high temperature to obtain the organic high-temperature resistant abrasive sealing coating. After curing, the coating exhibited a shear strength of 11.50 MPa, a tensile strength of 8.00 MPa, and a density of 1.48 g / cm³. 3 Other properties meet the aforementioned main performance indicators of the material.

[0065] Structural characterization and performance evaluation The microstructure, elemental composition, mechanical properties and temperature resistance of the organic high-temperature wear-resistant sealing coating prepared in Example 4 (taking Formulation 3 as an example) were evaluated.

[0066] Figure 1 This is a scanning electron microscope (SEM) image of the coating. The image shows that graphite, basalt fibers, serpentine fibers, and carbon fibers are randomly dispersed in the silicone resin matrix. This avoids the problems of low interlaminar shear strength or easy cracking along the orientation direction caused by parallel fiber arrangement, and is beneficial to enhancing the mechanical properties of the coating.

[0067] Figure 2The image shows the energy dispersive spectroscopy (EDS) analysis of the coating. The results indicate that the coating mainly contains five elements: C, O, Mg, Si, and Ca. C has the highest content and originates from graphite, carbon fiber, and silicone resin; Si has a relatively high content and originates from silicone resin, serpentine fiber, and basalt fiber; Mg and Ca mainly originate from serpentine fiber and basalt fiber, further confirming the material composition of the coating.

[0068] Figure 3 The images show the shear strength test specimen and cross-sectional SEM image of the coating on a polyimide / carbon fiber composite substrate. (a) and (b) show the specimen before and after the test, respectively, showing that the coating is present on both bonding surfaces, indicating that the fracture failure mode is cohesive failure. (c) is a cross-sectional SEM image, showing that the coating and the substrate interface are tightly bonded, proving that the coating has excellent adhesion to the composite substrate.

[0069] Figure 4 These are comparative photographs of the coating before and after 100 hours of heat aging at 350℃. (a) shows the coating before heat aging, and (b) and (c) show it after heat aging. The comparison shows no significant change in the coating, indicating that it has excellent temperature resistance.

[0070] Figure 5 The images show photographs of the sample and SEM images of the test surface after the coating bonding strength test. (a) and (b) show that a large amount of coating adheres to the substrate after the test, indicating that the fracture failure is cohesive failure; (c) is an SEM image of the test surface, where the bright areas are the metal substrates not covered by the coating, and the remaining areas are covered by the coating, indicating that the coating also has excellent adhesion to the metal substrate.

[0071] Figure 6 The figures show the shear strength-displacement curves of the coating on stainless steel and polyimide / carbon fiber composite substrates. The data in the figures indicate that the coating exhibits high mechanical strength on both substrates, demonstrating the potential for multi-scenario applications.

Claims

1. A method for preparing an organic high-temperature resistant, wear-resistant sealing coating material, characterized in that, Includes the following steps: (1) Solvent-free silicone resin is prepared by co-hydrolysis condensation reaction using alkoxysilanes including methyltriethoxysilane, methylphenyldiethoxysilane, phenyltrimethoxysilane and γ-(2,3-epoxypropoxy)propyltrimethoxysilane as necessary monomers. (2) The solvent-free silicone resin prepared in step (1) is mixed with graphite, basalt fiber, serpentine fiber and carbon fiber, and then stirred and ground in a mixer to obtain a uniformly mixed putty-like wearable sealing coating. (3) Apply the abrasive sealing coating obtained in step (2) to the substrate by smearing, and obtain the organic high temperature abrasive sealing coating after high temperature curing.

2. The preparation method according to claim 1, characterized in that, The specific preparation method of the solvent-free liquid silicone resin in step (1) is as follows: using toluene and anhydrous ethanol as solvents, add alkoxysilane monomers methyltriethoxysilane, methylphenyldiethoxysilane, phenyltrimethoxysilane and γ-(2,3-epoxypropoxy)propyltrimethoxysilane to obtain mixed solution 1; heat mixed solution 1 to 60-70℃, and then add phosphoric acid aqueous solution to mixed solution 1 dropwise to obtain mixed solution 2; reflux mixed solution 2 at 60-70℃ for 7h, then heat to 130-150℃ for reflux for 1.5h, and finally distill at 130-150℃ to obtain the solvent-free liquid silicone resin.

3. The preparation method according to claim 2, characterized in that, The amounts of each component by weight are as follows: 40-60 parts of methyltriethoxysilane, 50-60 parts of methylphenyldiethoxysilane, 10-30 parts of phenyltrimethoxysilane, and 5-10 parts of γ-(2,3-epoxypropoxy)propyltrimethoxysilane; solvents: 80-100 parts of toluene, 80-100 parts of anhydrous ethanol, and 70-100 parts of phosphoric acid aqueous solution.

4. The preparation method according to claim 3, characterized in that, The phosphoric acid aqueous solution is composed of 0.5-1.0 parts of phosphoric acid and 70-90 parts of deionized water.

5. The preparation method according to claim 1, characterized in that, The specific preparation method of the abrasive sealing coating in step (2) is as follows: graphite, basalt fiber, serpentine fiber and carbon fiber are added to the solvent-free liquid silicone resin for preliminary mixing, and then the resulting mixture is transferred to a mixer for stirring and grinding for 2-6 hours to obtain the abrasive sealing coating.

6. The preparation method according to claim 5, characterized in that, By weight, the amounts of each component in step (2) are as follows: 80-100 parts of solvent-free liquid silicone resin, 20-40 parts of graphite with a particle size of 300-350 mesh, 10-15 parts of basalt fiber with a length of 1-3 mm, 5-10 parts of serpentine fiber with a length of 1-3 mm, and 2-5 parts of carbon fiber with a length of 1-2 mm.

7. The preparation method according to claim 1, characterized in that, The high-temperature curing heat treatment process in step (3) is as follows: first, pre-treat at 80-110℃ for 1-2 hours, then treat at 160-200℃ for 2-4 hours, with a heating rate ≤3℃ / min.

8. The organic high-temperature wear-resistant sealing coating prepared by the method according to any one of claims 1 to 7, characterized in that, The room temperature shear strength is 8-12 MPa, the room temperature tensile strength is 6-8 MPa, and the coating density is 1.30-1.65 g / cm³. 3 Furthermore, after being kept at 350℃ for 100 hours, the coating showed no cracks, peeling, or powdering.

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