A method for preparing a superoleophobic coating for an aircraft engine radial oil pick-up ring

Abstract

The application relates to the technical field of aircraft engine coating, in particular to a super-oleophobic coating preparation method for a radial oil collecting ring of an aircraft engine, which comprises the following steps: cleaning the radial oil collecting ring; performing laser treatment on the surface of the radial oil collecting ring, so that the surface of the radial oil collecting ring has a honeycomb-shaped pit buffer array composed of a plurality of polygonal pits, each of the polygonal pits has a grid structure; spraying coating on the radial oil collecting ring after the laser treatment; performing plasma activation on the radial oil collecting ring with the coating, so that hydroxyl groups are generated on the surface of the coating; immersing the radial oil collecting ring after the plasma activation into a fluorosilicone solution, taking out and drying, and obtaining the radial oil collecting ring with the super-oleophobic coating. The buffer zone formed by the honeycomb-shaped pit buffer array can effectively relieve the impact of oil on the coating, the grid structure in the polygonal pit and the coating form a mechanical interlocking structure, the impact resistance of the coating is strengthened, and the working environment of the oil collecting ring can be adapted.

Description

Technical Field

[0001] This invention relates to the field of aircraft engine coating technology, and in particular to a method for preparing a superoleophobic coating for a radial oil-collecting ring of an aircraft engine. Background Technology

[0002] With the development of science and technology and the improvement of the aviation industry in my country, the main shaft speed in aircraft engines has increased to a high-speed level. Because aircraft engines operate under extreme conditions, requiring them to withstand high temperatures and pressures while maintaining stable performance, the lubrication of main shaft bearings often relies on efficient bearing lubrication technology to reduce wear. For main shaft bearings in aircraft engines, under-ring lubrication is commonly used. This method consists of two main parts: oil collection and oil delivery. The oil collection part is the first and crucial step in achieving under-ring lubrication, and it has two forms: axial and radial oil collection. Radial oil collection refers to the lubricating oil being sprayed out along a plane perpendicular to the rotating shaft after passing through the nozzle, and then collected by a radial oil collection ring, such as the oil collection ring disclosed in CN111878237A.

[0003] Radial oil collection rings are crucial structures in radial oil collection systems used to collect lubricating oil in the high-speed shafts of aircraft engines, and their oil collection efficiency directly affects the lubrication effect of the spindle bearings. However, traditional radial oil collection rings are typically made of stainless steel. Stainless steel has a strong affinity for lubricating oil, and its surface oil contact angle is low, causing lubricating oil to easily adhere to the ring during the oil collection process, leading to oil accumulation. This phenomenon results in poor bearing lubrication, heat buildup, and reduced bearing life.

[0004] Therefore, preparing superoleophobic coatings on the oil-collecting ring can reduce the adhesion of lubricating oil to the ring, thereby improving oil collection efficiency, which is of great significance for improving the lubrication performance of aircraft engine main shaft bearings. Existing technologies include oleophobic coatings, such as the long-lasting hydrophobic and oleophobic surface treatment process disclosed in CN105855151A, which involves etching a rough micro / nano structure on the substrate surface, then coating it with hydrophilic nano-silica sol and perfluoroanhydride alkyltriethoxysilane, and drying to obtain a hydrophobic and oleophobic layer. Another example is the hydrophobic and oleophobic coating and its preparation method disclosed in CN112979175A, which involves immersing the cleaned substrate in an aminoacrylic resin ethanol solution, then immersing it in a heptadecafluorodecyltriethoxysilane solution, and drying to obtain a hydrophobic and oleophobic coating. However, the radial oil-collecting ring of the high-speed shaft of an aircraft engine operates in a high-impact environment. Existing oleophobic coatings have poor adhesion; although the substrate surface has been roughened with micro / nano structures, it is still difficult to withstand the high impact of oil, easily leading to coating failure and ultimately resulting in poor oleophobic effect, failing to improve the ring's oil collection efficiency. Summary of the Invention

[0005] The purpose of this invention is to propose a method for preparing a superoleophobic coating for a radial oil catch ring of an aircraft engine. By setting a buffer zone formed by a honeycomb pit buffer array, the impact of oil on the coating can be effectively mitigated. The grid structure in the polygonal pits forms a mechanical interlocking structure with the coating. The composite structure of buffering and mechanical interlocking plays a synergistic protective role for the coating, enhances the impact resistance of the coating, and can adapt to the working environment of the oil catch ring.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] A method for preparing a superoleophobic coating for a radial oil-collecting ring in an aircraft engine, wherein the inner wall of the radial oil-collecting ring is arc-shaped, the method comprising the following steps:

[0008] (1) Clean the radial oil collection ring;

[0009] (2) The surface of the radial oil collection ring is laser-treated, and the surface of the radial oil collection ring has a honeycomb-shaped pit buffer array composed of multiple polygonal pits, and each polygonal pit has a grid structure.

[0010] (3) Spray coating onto the radial oil-collecting ring after laser treatment;

[0011] (4) Plasma activation is performed on the radial oil-collecting ring with the coating to generate hydroxyl groups on the coating surface;

[0012] (5) Immerse the plasma-activated radial oil-collecting ring in a fluorosiloxane solution, remove and dry it to obtain a radial oil-collecting ring with a superoleophobic coating.

[0013] Furthermore, in step (2), the depth of the polygonal pit is 20-30 μm, the maximum diameter is 80-100 μm, and the distance between two adjacent polygonal pits is less than 10 μm.

[0014] The mesh structure is located at the bottom of the polygonal pit, and the height of the mesh structure is 6 to 10 μm, with a mesh spacing of about 5 μm.

[0015] Furthermore, the sidewall of the polygonal recess includes a vertical wall and an inclined wall, with the bottom edge of the inclined wall connecting to the top edge of the vertical wall;

[0016] The angle between the inclined wall and the vertical wall is 150-160°.

[0017] Furthermore, step (3) includes:

[0018] Preheat the radial oil-collecting ring to be sprayed;

[0019] The preheated radial oil-retaining ring is first coated, and then baked.

[0020] Apply a second coat to the radial oil-collecting ring, then bake it. Repeat this process at least three times.

[0021] Finally, the radial oil-collecting ring is dried at room temperature.

[0022] Furthermore, the coating comprises hydrophobic silica nanoparticles, tetrahydrofuran, isopropanol, and methylphenyl silicone resin.

[0023] The preheating temperature for the radial oil-retaining ring to be sprayed is 50-70℃, the baking temperature after spraying the radial oil-retaining ring is 50-70℃, and the baking temperature after the last spray is 40℃.

[0024] Furthermore, the method for preparing the coating includes:

[0025] Hydrophobic silica nanoparticles were added to a mixture of tetrahydrofuran and isopropanol and then ultrasonically dispersed. Methylphenyl silicone resin was then added and ultrasonically dispersed again.

[0026] The volume ratio of tetrahydrofuran to isopropanol is 2:3, and the mass ratio of the hydrophobic silica nanoparticles to the methylphenyl silicone resin is (4-5):1.

[0027] Furthermore, the coating thickness is 16–20 μm, and the thickness of each spray is 4–5 μm.

[0028] Furthermore, in step (4), the radial oil-collecting ring that has completed step (3) is placed in air at room temperature for more than 2 hours, and then the radial oil-collecting ring is placed in a plasma instrument and plasma-treated for 40 to 60 minutes under oxygen conditions.

[0029] Furthermore, in step (5), the radial oil-collecting ring that has completed step (4) is immersed in a 5 wt% fluorosiloxane ethanol solution for 10 to 15 minutes.

[0030] Remove and dry at room temperature to obtain a superoleophobic coating.

[0031] Furthermore, the fluorosiloxane is one or both of heptadecafluorodecyltriethoxysilane and tridecafluorooctyltriethoxysilane.

[0032] The technical solution provided by this invention may include the following beneficial effects:

[0033] 1. The buffer zone formed by setting up a honeycomb-shaped pit buffer array can effectively reduce the impact of oil on the coating. The grid structure in the polygonal pits forms a mechanical interlocking structure with the coating. The composite structure of buffering and mechanical interlocking plays a synergistic protective role for the coating, enhances the coating's impact resistance, and can adapt to the working environment of the oil recovery ring.

[0034] 2. In this method, the radial oil-collecting ring with the coating is plasma activated, which generates a large number of hydroxyl groups (-OH) on the coating surface. The -Si(OCH3)3 group at one end of the fluorosilane oxygen molecule undergoes a hydrolysis and condensation reaction with the hydroxyl groups on the coating surface to form a strong covalent bond. The long-chain perfluoroalkyl group at the other end is arranged obliquely and densely on the coating surface to form a low surface energy monolayer, which greatly reduces the surface energy. Combined with the coating, a superoleophobic effect is achieved.

[0035] 3. The method of spraying a coating onto the irregular curved surface of the radial oil-collecting ring by preheating and multiple sprayings results in a uniform coating thickness and uniform distribution of nanoparticles, thereby improving the oleophobic effect of the coating. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of a honeycomb-shaped pit buffer array on the surface of a radial oil-collecting ring according to an embodiment of the present invention;

[0037] Figure 2 This is a cross-sectional schematic diagram of a polygonal indentation. Detailed Implementation

[0038] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the present invention.

[0039] This invention discloses a method for preparing a superoleophobic coating for a radial oil-collecting ring in an aircraft engine, wherein the inner wall of the radial oil-collecting ring is arc-shaped. The method includes the following steps:

[0040] (1) Clean the radial oil collection ring;

[0041] (2) The surface of the radial oil collection ring is laser-treated to create a honeycomb-shaped pit buffer array composed of multiple polygonal pits on the surface of the radial oil collection ring. Figure 1 Each of the polygonal recesses has a mesh structure;

[0042] (3) Spray coating onto the radial oil-collecting ring after laser treatment;

[0043] (4) Plasma activation is performed on the radial oil-collecting ring with the coating to generate hydroxyl groups on the coating surface;

[0044] (5) Immerse the plasma-activated radial oil-collecting ring in a fluorosiloxane solution, remove and dry it to obtain a radial oil-collecting ring with a superoleophobic coating.

[0045] In this method, the buffer zone formed by setting up a honeycomb-shaped pit buffer array can effectively alleviate the impact of oil on the coating. The grid structure in the polygonal pits forms a mechanical interlocking structure with the coating. The composite structure of buffering and mechanical interlocking plays a synergistic protective role for the coating, enhances the coating's impact resistance, and can adapt to the working environment of the oil recovery ring.

[0046] Furthermore, in this method, the radial oil-absorbing rings with the coating are plasma-activated, generating a large number of hydroxyl groups (-OH) on the coating surface, providing reaction sites for subsequent chemical bonding of fluorosilanes. When fluorosiloxanes adhere to the coating surface, the -Si(OCH3)3 group at one end of the fluorosilane oxygen molecule undergoes a hydrolytic condensation reaction with the hydroxyl groups on the coating surface, forming a strong covalent bond for stable bonding. The long-chain perfluoroalkyl groups at the other end of the fluorosilane oxygen molecule are arranged obliquely and densely on the coating surface, forming a low surface energy monolayer, significantly reducing surface energy and achieving a superoleophobic effect.

[0047] It should be noted that the unactivated coating surface contains inert methyl (-CH3) and siloxane (-Si-O-) groups (when the coating material contains nano-silica particles and methyl-containing resins). Fluorosiloxanes can only physically adsorb onto the coating surface, forming a sparse and unstable fluorocarbon layer. Furthermore, the presence of high surface energy groups such as -CH3 on the coating surface leads to easy oil spread, ultimately resulting in poor oleophobic performance. In contrast, the plasma activation in this solution transforms the coating surface into a high-density hydroxyl group (-OH) through oxygen free radical bombardment. This allows one end of the fluorosiloxane to achieve dense grafting through covalent condensation, while the other end forms an orderly perfluoroalkyl chain (-CF2-CF3) ultra-low surface energy layer, ultimately achieving an effective and stable oleophobic effect.

[0048] In one embodiment of the present invention, in step (2), the depth of the polygonal pit is 20-30 μm, the maximum diameter is 80-100 μm, and two adjacent polygonal pits ( Figure 2 The spacing between the particles is less than 10 μm;

[0049] The mesh structure is located at the bottom of the polygonal pit, and the height of the mesh structure is 6 to 10 μm, with a mesh spacing of about 5 μm.

[0050] This design utilizes polygonal recesses with relatively large diameters and depths to buffer high-speed oil flow and protect the coating. Recesses that are too large or too small will not provide adequate oil buffering. The mesh structure at the bottom of the polygonal recesses enhances coating adhesion, further improves impact resistance, and reduces oleophobic angle attenuation.

[0051] Specifically, when processing a honeycomb-shaped pit buffer array with laser, a polygonal pit array is first formed, and then a secondary mesh structure is processed within the polygonal pits to form a combination of honeycomb pits and secondary mesh.

[0052] In one embodiment of the present invention, the sidewall of the polygonal recess includes a vertical wall and an inclined wall, the bottom edge of the inclined wall connecting to the top edge of the vertical wall; the angle between the inclined wall and the vertical wall is 150-160°. If the inclination of the inclined wall is too large, the buffering effect on the oil is weakened; if the inclination angle is too small, it creates resistance to the flow of oil, affecting the oil collection effect.

[0053] The irregular curved surface of the radial oil-collecting ring requires ensuring a uniform coating thickness and resistance to cracking. In order to form a highly stable coating on the irregular curved surface of the radial oil-collecting ring, in one embodiment of the present invention, step (3) includes:

[0054] Preheat the radial oil-collecting ring to be sprayed;

[0055] The preheated radial oil-retaining ring is first coated, and then baked.

[0056] Apply a second coat to the radial oil-collecting ring, then bake it. Repeat this process at least three times.

[0057] Finally, the radial oil-collecting ring is dried at room temperature.

[0058] This solution uses a preheated, multi-coat spraying method to apply a coating to the irregular curved surface of the radial oil-collecting ring. This solves the problem of paint dripping on the irregular curved surface of the oil-collecting ring after spraying, and prevents paint accumulation in the edge area, which would lead to nanoparticle agglomeration.

[0059] Preferably, the coating comprises hydrophobic silica nanoparticles, tetrahydrofuran, isopropanol, and methylphenyl silicone resin;

[0060] The preheating temperature for the radial oil-retaining ring to be sprayed is 50-70℃, the baking temperature after spraying the radial oil-retaining ring is 50-70℃, and the baking temperature after the last spray is 40℃.

[0061] The preheating temperature range is 50℃-70℃, with 60℃ being the preferred temperature. Temperatures that are too low cannot effectively evaporate the solvent, while temperatures that are too high will lead to coating defects. More preferably, the radial oil-collecting ring is preheated to 60℃ for later use, followed by spraying with a high-atomization spray gun, and then cured at 60℃. Since the solvent system consists of tetrahydrofuran and isopropanol, with tetrahydrofuran having a boiling point of 66℃, the surface preheating of the substrate combined with the subsequent brief curing helps to quickly evaporate this solvent. The remaining methylphenyl silicone resin results in higher coating adhesion and effectively suppresses sagging. Based on preheating and baking after each spraying, the coating thickness is uniform and the nanoparticles are evenly distributed.

[0062] The honeycomb-shaped pit buffer array, combined with the multi-layered roughness of nano-SiO2 particles constructed through multiple spraying processes, forms a stable Cassie-Baxter state at the fluorosiloxane-modified layer (ultra-low surface energy) on the radial oil-collecting ring surface where oil contacts. An air film within the pits prevents oil penetration, further enhancing the oleophobic properties. Simultaneously, methylphenyl silicone resin in the coating acts as a binder (film-forming agent), adhering the nanoparticles to the part surface. This resin possesses a certain degree of flexibility, preventing cracking on irregular curved surfaces of the ring, and its high-temperature resistance ensures the coating remains stable under high-temperature conditions.

[0063] The hydrophobic silica nanoparticles in this invention have a particle size of 7nm-40nm, and the hydrophobic silica nanoparticles in the embodiments of this invention have a particle size of 15nm.

[0064] Furthermore, the method for preparing the coating includes:

[0065] Hydrophobic silica nanoparticles were added to a mixture of tetrahydrofuran and isopropanol and then ultrasonically dispersed. Methylphenyl silicone resin was then added and ultrasonically dispersed again.

[0066] The volume ratio of tetrahydrofuran to isopropanol is 2:3, and the mass ratio of the hydrophobic silica nanoparticles to the methylphenyl silicone resin is (4-5):1.

[0067] In a solvent system of 40% tetrahydrofuran and 60% isopropanol, tetrahydrofuran can effectively dissolve the resin and prevent it from agglomerating. The addition of isopropanol is used to dilute the tetrahydrofuran and maintain its high solubility. At the same time, the surface tension of the prepared solvent is moderate, which helps the nanoparticles to be stably suspended and not easily agglomerate. It also promotes the orderly accumulation of nanoparticles during solvent evaporation, reduces defects, and thus forms a stable rough structure.

[0068] The coating thickness in this invention is 16–20 μm, with each spray application covering 4–5 μm. This thickness provides good flexibility and sufficient surface roughness. Based on the mesh structure's height of 6–10 μm and mesh spacing of approximately 5 μm, the mesh achieves a good mechanical interlocking structure with the coating.

[0069] In one embodiment of the present invention, in step (4), the radial oil-collecting ring that has completed step (3) is placed in air at room temperature for more than 2 hours, and then placed in a plasma instrument for plasma treatment under oxygen purging for 40-60 minutes. The radial oil-collecting ring with coating is placed in air at room temperature for several hours to ensure complete solvent evaporation. Plasma treatment under oxygen purging allows a large number of hydroxyl groups to be generated on the coating surface.

[0070] In one embodiment of the present invention, in step (5), the radial oil-collecting ring that has completed step (4) is immersed in a 5 wt% fluorosiloxane ethanol solution for 10-15 minutes; it is then removed and dried at room temperature to obtain a superoleophobic coating. During this process, the fluorosiloxane adheres to the coating surface and undergoes a condensation reaction with the hydroxyl groups on the coating surface during the subsequent drying process. If the immersion time in the fluorosiloxane ethanol solution is too long, excessive amounts of fluorosiloxane will adhere, affecting the orderly arrangement of the perfluoroalkyl chains (-CF2-CF3).

[0071] Specifically, the fluorosiloxane is one or both of heptadecafluorodecyltriethoxysilane and tridecafluorooctyltriethoxysilane.

[0072] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments that do not specify specific conditions are generally performed according to conventional methods and conditions or according to the product instructions. Unless otherwise specified, the reagents mentioned are commercially available; and the performance of products from different sources does not have a significant impact.

[0073] Example 1

[0074] The method for preparing a superoleophobic coating for a radial oil-collecting ring of an aircraft engine in this embodiment includes the following steps:

[0075] (1) Cleaning the radial oil-collecting ring: First, put it in acetone solution for ultrasonic cleaning for 5 minutes, then put it in deionized water for ultrasonic cleaning for 5 minutes, and finally take out the radial oil-collecting ring and let it air dry for later use.

[0076] (2) The surface of the radial oil-collecting ring is laser-treated (laser beam power 20W, pulse width 10ns, wavelength 1064nm). The surface of the radial oil-collecting ring has a honeycomb-shaped pit buffer array composed of multiple polygonal pits, each of which has a grid structure. The depth of the polygonal pit is 30μm, the maximum diameter is 100μm, and the distance between two adjacent polygonal pits is less than 10μm. The height of the grid structure is 6μm, and the grid spacing is about 5μm. The angle between the inclined wall of the sidewall of the polygonal pit and the vertical wall is 150-160°.

[0077] (3) Apply coating to the laser-treated radial oil-collecting ring:

[0078] Coating preparation: 13.5g of hydrophobic silica nanoparticles were added to a mixture of 400ml tetrahydrofuran and 600ml isopropanol and ultrasonically dispersed. Then, 3g of methylphenyl silicone resin was added and ultrasonically dispersed again. The volume ratio of tetrahydrofuran to isopropanol was 2:3.

[0079] Spraying: Preheat the radial oil-collecting ring to be sprayed at 50-70℃ for more than 60 minutes;

[0080] The preheated radial oil-collecting ring was first sprayed with a thickness of 4μm, and then baked at 60℃ for 30s.

[0081] A second coating is applied to the radial oil-collecting ring, with a coating thickness of approximately 4 μm. Then, it is baked at 60°C for 30 seconds. This process is repeated four times. The final coating is baked at 40°C for constant temperature curing.

[0082] Finally, the radial oil-collecting ring was dried at room temperature, and the resulting coating thickness was approximately 16 μm.

[0083] (4) Place the radial oil-collecting ring that has completed step (3) in air at room temperature for more than 2 hours, and then place the radial oil-collecting ring in a plasma instrument and plasma treat it for 60 minutes under oxygen conditions.

[0084] (5) Immerse the plasma-activated radial oil-collecting ring in a 5wt% heptadecafluorodecyltriethoxysilane ethanol solution for 15 min, remove and dry to obtain a radial oil-collecting ring with a superoleophobic coating.

[0085] Example 2

[0086] The method for preparing a superoleophobic coating for a radial oil-collecting ring of an aircraft engine in this embodiment includes the following steps:

[0087] (1) Cleaning the radial oil-collecting ring: First, put it in acetone solution for ultrasonic cleaning for 5 minutes, then put it in deionized water for ultrasonic cleaning for 5 minutes, and finally take out the radial oil-collecting ring and let it air dry for later use.

[0088] (2) The surface of the radial oil-collecting ring is laser-treated (laser beam power 20W, pulse width 10ns, wavelength 1064nm). The surface of the radial oil-collecting ring has a honeycomb-shaped pit buffer array composed of multiple polygonal pits, each of which has a grid structure. The depth of the polygonal pit is 20μm, the maximum diameter is 100μm, and the distance between two adjacent polygonal pits is less than 10μm. The height of the grid structure is 6μm, and the grid spacing is about 5μm. The angle between the inclined wall of the sidewall of the polygonal pit and the vertical wall is 150-160°.

[0089] (3) Apply coating to the laser-treated radial oil-collecting ring:

[0090] Coating preparation: 13.5g of hydrophobic silica nanoparticles were added to a mixture of 400ml tetrahydrofuran and 600ml isopropanol and ultrasonically dispersed. Then, 3g of methylphenyl silicone resin was added and ultrasonically dispersed again. The volume ratio of tetrahydrofuran to isopropanol was 2:3.

[0091] Spraying: Preheat the radial oil-collecting ring to be sprayed at 50-70℃ for more than 60 minutes;

[0092] The preheated radial oil-collecting ring was first sprayed with a thickness of 4μm, and then baked at 60℃ for 30s.

[0093] A second coating is applied to the radial oil-collecting ring, with a coating thickness of approximately 4 μm. Then, it is baked at 60°C for 30 seconds. This process is repeated four times. The final coating is baked at 40°C for constant temperature curing.

[0094] Finally, the radial oil-collecting ring was dried at room temperature, and the resulting coating thickness was approximately 16 μm.

[0095] (4) Place the radial oil-collecting ring that has completed step (3) in air at room temperature for more than 2 hours, and then place the radial oil-collecting ring in a plasma instrument and plasma treat it for 60 minutes under oxygen conditions.

[0096] (5) Immerse the plasma-activated radial oil-collecting ring in a 5wt% solution of heptadecafluorodecyltriethoxysilane and tridecafluorooctyltriethoxysilane for 15 min, remove and dry to obtain a radial oil-collecting ring with a superoleophobic coating.

[0097] Example 3

[0098] The method for preparing a superoleophobic coating for a radial oil-collecting ring of an aircraft engine in this embodiment includes the following steps:

[0099] (1) Cleaning the radial oil-collecting ring: First, put it in acetone solution for ultrasonic cleaning for 5 minutes, then put it in deionized water for ultrasonic cleaning for 5 minutes, and finally take out the radial oil-collecting ring and let it air dry for later use.

[0100] (2) The surface of the radial oil-collecting ring is laser-treated (laser beam power 20W, pulse width 10ns, wavelength 1064nm). The surface of the radial oil-collecting ring has a honeycomb-shaped pit buffer array composed of multiple polygonal pits, each of which has a grid structure. The depth of the polygonal pit is 30μm, the maximum diameter is 100μm, and the distance between two adjacent polygonal pits is less than 10μm. The height of the grid structure is 6μm, and the grid spacing is about 5μm. The angle between the inclined wall of the sidewall of the polygonal pit and the vertical wall is 150-160°.

[0101] (3) Apply coating to the laser-treated radial oil-collecting ring:

[0102] Coating preparation: 12g of hydrophobic silica nanoparticles were added to a mixture of 400ml tetrahydrofuran and 600ml isopropanol and ultrasonically dispersed. Then, 3g of methylphenyl silicone resin was added and ultrasonically dispersed again. The volume ratio of tetrahydrofuran to isopropanol was 2:3.

[0103] Spraying: Preheat the radial oil-collecting ring to be sprayed at 50-70℃ for more than 60 minutes;

[0104] The preheated radial oil-collecting ring was first sprayed with a thickness of 4μm, and then baked at 60℃ for 30s.

[0105] A second coating of approximately 5 μm is applied to the radial oil-collecting ring, followed by baking at 60°C for 30 seconds. This process is repeated four times, with the final coating baked at 40°C for constant temperature curing.

[0106] Finally, the radial oil-collecting ring was dried at room temperature, and the resulting coating thickness was approximately 20 μm.

[0107] (4) Place the radial oil-collecting ring that has completed step (3) in air at room temperature for more than 2 hours, and then place the radial oil-collecting ring in a plasma instrument and plasma treat it for 60 minutes under oxygen conditions.

[0108] (5) Immerse the plasma-activated radial oil-collecting ring in a 5wt% solution of heptadecafluorodecyltriethoxysilane and tridecafluorooctyltriethoxysilane for 15 min, remove and dry to obtain a radial oil-collecting ring with a superoleophobic coating.

[0109] Example 4

[0110] The method for preparing a superoleophobic coating for a radial oil-collecting ring of an aircraft engine in this embodiment includes the following steps:

[0111] (1) Cleaning the radial oil-collecting ring: First, put it in acetone solution for ultrasonic cleaning for 5 minutes, then put it in deionized water for ultrasonic cleaning for 5 minutes, and finally take out the radial oil-collecting ring and let it air dry for later use.

[0112] (2) The surface of the radial oil-collecting ring is laser-treated (laser beam power 20W, pulse width 10ns, wavelength 1064nm). The surface of the radial oil-collecting ring has a honeycomb-shaped pit buffer array composed of multiple polygonal pits, each of which has a grid structure. The depth of the polygonal pit is 30μm, the maximum diameter is 80μm, and the distance between two adjacent polygonal pits is less than 10μm. The height of the grid structure is 6μm, and the grid spacing is about 5μm. The angle between the inclined wall of the sidewall of the polygonal pit and the vertical wall is 150-160°.

[0113] (3) Apply coating to the laser-treated radial oil-collecting ring:

[0114] Coating preparation: 13.5g of hydrophobic silica nanoparticles were added to a mixture of 400ml tetrahydrofuran and 600ml isopropanol and ultrasonically dispersed. Then, 3g of methylphenyl silicone resin was added and ultrasonically dispersed again. The volume ratio of tetrahydrofuran to isopropanol was 2:3.

[0115] Spraying: Preheat the radial oil-collecting ring to be sprayed at 50-70℃ for more than 60 minutes;

[0116] The preheated radial oil-collecting ring was first sprayed with a thickness of 4μm, and then baked at 60℃ for 30s.

[0117] A second coating is applied to the radial oil-collecting ring, with a coating thickness of approximately 4 μm. Then, it is baked at 60°C for 30 seconds. This process is repeated four times. The final coating is baked at 40°C for constant temperature curing.

[0118] Finally, the radial oil-collecting ring was dried at room temperature, and the resulting coating thickness was approximately 16 μm.

[0119] (4) Place the radial oil-collecting ring that has completed step (3) in air at room temperature for more than 2 hours, and then place the radial oil-collecting ring in a plasma instrument and plasma treat it for 60 minutes under oxygen conditions.

[0120] (5) Immerse the plasma-activated radial oil-collecting ring in a 5wt% solution of heptadecafluorodecyltriethoxysilane and tridecafluorooctyltriethoxysilane for 15 min, remove and dry to obtain a radial oil-collecting ring with a superoleophobic coating.

[0121] Example 5

[0122] The method for preparing a superoleophobic coating for a radial oil-collecting ring of an aircraft engine in this embodiment includes the following steps:

[0123] (1) Cleaning the radial oil-collecting ring: First, put it in acetone solution for ultrasonic cleaning for 5 minutes, then put it in deionized water for ultrasonic cleaning for 5 minutes, and finally take out the radial oil-collecting ring and let it air dry for later use.

[0124] (2) The surface of the radial oil-collecting ring is laser-treated (laser beam power 20W, pulse width 10ns, wavelength 1064nm). The surface of the radial oil-collecting ring has a honeycomb-shaped pit buffer array composed of multiple polygonal pits, each of which has a grid structure. The depth of the polygonal pit is 30μm, the maximum diameter is 100μm, and the distance between two adjacent polygonal pits is less than 10μm. The height of the grid structure is 6μm, and the grid spacing is about 5μm. The angle between the inclined wall of the sidewall of the polygonal pit and the vertical wall is 150-160°.

[0125] (3) Apply coating to the laser-treated radial oil-collecting ring:

[0126] Coating preparation: 15g of hydrophobic silica nanoparticles were added to a mixture of 400ml tetrahydrofuran and 600ml isopropanol and ultrasonically dispersed. Then, 3g of methylphenyl silicone resin was added and ultrasonically dispersed again. The volume ratio of tetrahydrofuran to isopropanol was 2:3.

[0127] Spraying: Preheat the radial oil collection ring to be sprayed at 60℃ for at least 60 minutes;

[0128] The preheated radial oil-collecting ring was first sprayed with a thickness of 4μm, and then baked at 60℃ for 30s.

[0129] A second coating is applied to the radial oil-collecting ring, with a coating thickness of approximately 4 μm. Then, it is baked at 60°C for 30 seconds. This process is repeated four times. The final coating is baked at 40°C for constant temperature curing.

[0130] Finally, the radial oil-collecting ring was dried at room temperature, and the resulting coating thickness was approximately 16 μm.

[0131] (4) Place the radial oil-collecting ring that has completed step (3) in air at room temperature for more than 2 hours, and then place the radial oil-collecting ring in a plasma instrument and plasma treat it for 60 minutes under oxygen conditions.

[0132] (5) Immerse the plasma-activated radial oil-collecting ring in a 5wt% solution of heptadecafluorodecyltriethoxysilane and tridecafluorooctyltriethoxysilane for 15 min, remove and dry to obtain a radial oil-collecting ring with a superoleophobic coating.

[0133] Example 6

[0134] The method for preparing a superoleophobic coating for a radial oil-collecting ring of an aircraft engine in this embodiment includes the following steps:

[0135] (1) Cleaning the radial oil-collecting ring: First, put it in acetone solution for ultrasonic cleaning for 5 minutes, then put it in deionized water for ultrasonic cleaning for 5 minutes, and finally take out the radial oil-collecting ring and let it air dry for later use.

[0136] (2) The surface of the radial oil-collecting ring is laser-treated (laser beam power 20W, pulse width 10ns, wavelength 1064nm). The surface of the radial oil-collecting ring has a honeycomb-shaped pit buffer array composed of multiple polygonal pits, each of which has a grid structure. The depth of the polygonal pit is 30μm, the maximum diameter is 100μm, and the distance between two adjacent polygonal pits is less than 10μm. The height of the grid structure is 6μm, and the grid spacing is about 5μm. The angle between the inclined wall of the sidewall of the polygonal pit and the vertical wall is 150-160°.

[0137] (3) Apply coating to the laser-treated radial oil-collecting ring:

[0138] Coating preparation: 13.5g of hydrophobic silica nanoparticles were added to a mixture of 400ml tetrahydrofuran and 600ml isopropanol and ultrasonically dispersed. Then, 3g of methylphenyl silicone resin was added and ultrasonically dispersed again. The volume ratio of tetrahydrofuran to isopropanol was 2:3.

[0139] Spraying: Preheat the radial oil collection ring to be sprayed at 70℃ for at least 60 minutes;

[0140] The preheated radial oil-collecting ring was first sprayed with a thickness of 4μm, and then baked at 70℃ for 30s.

[0141] A second coating is applied to the radial oil-collecting ring, with a coating thickness of approximately 4 μm. Then, it is baked at 70°C for 30 seconds. This process is repeated four times. The final coating is baked at 40°C for constant temperature curing.

[0142] Finally, the radial oil-collecting ring was dried at room temperature, and the resulting coating thickness was approximately 16 μm.

[0143] (4) Place the radial oil-collecting ring that has completed step (3) in air at room temperature for more than 2 hours, and then place the radial oil-collecting ring in a plasma instrument and plasma treat it for 60 minutes under oxygen conditions.

[0144] (5) Immerse the plasma-activated radial oil-collecting ring in a 5wt% solution of heptadecafluorodecyltriethoxysilane and tridecafluorooctyltriethoxysilane for 15 min, remove and dry to obtain a radial oil-collecting ring with a superoleophobic coating.

[0145] Example 7

[0146] The method for preparing a superoleophobic coating for a radial oil-collecting ring of an aircraft engine in this embodiment includes the following steps:

[0147] (1) Cleaning the radial oil-collecting ring: First, put it in acetone solution for ultrasonic cleaning for 5 minutes, then put it in deionized water for ultrasonic cleaning for 5 minutes, and finally take out the radial oil-collecting ring and let it air dry for later use.

[0148] (2) The surface of the radial oil-collecting ring is laser-treated (laser beam power 20W, pulse width 10ns, wavelength 1064nm). The surface of the radial oil-collecting ring has a honeycomb-shaped pit buffer array composed of multiple polygonal pits, each of which has a grid structure. The depth of the polygonal pit is 30μm, the maximum diameter is 100μm, and the distance between two adjacent polygonal pits is less than 10μm. The height of the grid structure is 6μm, and the grid spacing is about 5μm. The angle between the inclined wall of the sidewall of the polygonal pit and the vertical wall is 150-160°.

[0149] (3) Apply coating to the laser-treated radial oil-collecting ring:

[0150] Coating preparation: 13.5g of hydrophobic silica nanoparticles were added to a mixture of 400ml tetrahydrofuran and 600ml isopropanol and ultrasonically dispersed. Then, 3g of methylphenyl silicone resin was added and ultrasonically dispersed again. The volume ratio of tetrahydrofuran to isopropanol was 2:3.

[0151] Spraying: Preheat the radial oil collection ring to be sprayed at 50℃ for at least 60 minutes;

[0152] The preheated radial oil-collecting ring was first sprayed with a thickness of 4μm, and then baked at 50℃ for 30s.

[0153] A second coating is applied to the radial oil-collecting ring, with a coating thickness of approximately 4 μm. Then, it is baked at 50°C for 30 seconds. This process is repeated four times. The final coating is baked at 40°C for constant temperature curing.

[0154] Finally, the radial oil-collecting ring was dried at room temperature, and the resulting coating thickness was approximately 16 μm.

[0155] (4) Place the radial oil-collecting ring that has completed step (3) in air at room temperature for more than 2 hours, and then place the radial oil-collecting ring in a plasma instrument and plasma treat it for 60 minutes under oxygen conditions.

[0156] (5) Immerse the plasma-activated radial oil-collecting ring in a 5wt% solution of heptadecafluorodecyltriethoxysilane and tridecafluorooctyltriethoxysilane for 15 min, remove and dry to obtain a radial oil-collecting ring with a superoleophobic coating.

[0157] Example 8

[0158] The method for preparing a superoleophobic coating for a radial oil-collecting ring of an aircraft engine in this embodiment includes the following steps:

[0159] (1) Cleaning the radial oil-collecting ring: First, put it in acetone solution for ultrasonic cleaning for 5 minutes, then put it in deionized water for ultrasonic cleaning for 5 minutes, and finally take out the radial oil-collecting ring and let it air dry for later use.

[0160] (2) The surface of the radial oil-collecting ring is laser-treated (laser beam power 20W, pulse width 10ns, wavelength 1064nm). The surface of the radial oil-collecting ring has a honeycomb-shaped pit buffer array composed of multiple polygonal pits, each of which has a grid structure. The depth of the polygonal pit is 30μm, the maximum diameter is 100μm, and the distance between two adjacent polygonal pits is less than 10μm. The height of the grid structure is 6μm, and the grid spacing is about 5μm. The angle between the inclined wall of the sidewall of the polygonal pit and the vertical wall is 150-160°.

[0161] (3) Apply coating to the laser-treated radial oil-collecting ring:

[0162] Coating preparation: 13.5g of hydrophobic silica nanoparticles were added to a mixture of 400ml tetrahydrofuran and 600ml isopropanol and ultrasonically dispersed. Then, 3g of methylphenyl silicone resin was added and ultrasonically dispersed again. The volume ratio of tetrahydrofuran to isopropanol was 2:3.

[0163] Spraying: Preheat the radial oil collection ring to be sprayed at 60℃ for at least 60 minutes;

[0164] The preheated radial oil-collecting ring was first sprayed with a thickness of 4μm, and then baked at 60℃ for 30s.

[0165] A second coating is applied to the radial oil-collecting ring, with a coating thickness of approximately 4 μm. Then, it is baked at 60°C for 30 seconds. This process is repeated four times. The final coating is baked at 40°C for constant temperature curing.

[0166] Finally, the radial oil-collecting ring was dried at room temperature, and the resulting coating thickness was approximately 16 μm.

[0167] (4) Place the radial oil-collecting ring that has completed step (3) in air at room temperature for more than 2 hours, and then place the radial oil-collecting ring in a plasma instrument and plasma treat it for 60 minutes under oxygen conditions.

[0168] (5) Immerse the plasma-activated radial oil-collecting ring in a 5wt% solution of heptadecafluorodecyltriethoxysilane and tridecafluorooctyltriethoxysilane for 10 min, remove and dry to obtain a radial oil-collecting ring with a superoleophobic coating.

[0169] Comparative Example 1

[0170] The method for preparing the oleophobic coating in this comparative example is basically the same as that in Example 1. The difference is that this comparative example lacks step (2) and does not perform surface laser treatment on the radial oil-collecting ring.

[0171] Comparative Example 2

[0172] The preparation method of the oleophobic coating in this comparative example group is basically the same as that in Example 1. The difference is that the maximum diameters of the polygonal pits in this comparative example group are 40μm, 60μm, 140μm and 180μm, respectively.

[0173] Comparative Example 3

[0174] The preparation method of the oleophobic coating in this comparative example is basically the same as that in Example 1. The difference is that the depth of the polygonal pits and the mesh height in this comparative example are 6μm / 2μm, 45μm / 15μm and 60μm / 20μm, respectively.

[0175] Comparative Example 4

[0176] The method for preparing the oleophobic coating in this comparative example is basically the same as that in Example 1. The difference is that step (4) is missing in this comparative example, and plasma treatment is not performed.

[0177] Comparative Example 5

[0178] The preparation method of the oleophobic coating in this comparative example is basically the same as that in Example 1. The difference is that in step (3) of this comparative example, the preheated radial oil-collecting ring is sprayed once, baked, and then sprayed again. Only two sprays are performed, and the thickness of each spray is about 8 μm.

[0179] The experiment was conducted using a bent stainless steel sheet to simulate the inner wall of the radial oil collection ring. An oleophobic coating was applied to the surface of the stainless steel sheet using the methods of Examples 1-8 and Comparative Examples 1-6, respectively. Then, the oil contact angle was tested. The stainless steel sheet was subjected to oil impact for 60 minutes, and the oil contact angle decay rate was calculated.

[0180] The contact angle and attenuation rate of the oil before impact in Examples 1 to 8 are shown in the table below.

[0181]

[0182] The contact angles and attenuation rates of the oil before impact for Comparative Examples 1-6 are shown in the table below.

[0183] project Comparative Example 1 Comparative Example 2-1 Comparative Example 2-2 Comparative Examples 2-3 Comparative Examples 2-4 Oil contact angle before impact 140° 154° 154° 154° 154° Attenuation rate 26.40％ 6.70％ 4.30％ 5.10％ 8.60％ project Comparative Example 3-1 Comparative Example 3-2 Comparative Example 3-3 Comparative Example 4 Comparative Example 5 Oil contact angle before impact 154° 154° 154° 124° 136° Attenuation rate 22.10％ 10.40％ 23.80％ 4.90％ 6.80％

[0184] The influence of radial oil-collecting ring wetting characteristics (contact angle) on oil collection efficiency was investigated using simulation software. The data obtained are as follows when the lubricating oil injection speed, oil viscosity, and rotation speed are constant:

[0185] Oil contact angle Oil recovery efficiency 45° 59.2％ 75° 70％ 90° 76％ 135° 86％ 165° 96％

[0186] It is evident that increasing the oil contact angle on the surface of the radial oil-collecting ring can significantly improve the oil collection efficiency. The coatings obtained in Examples 1-8 of this invention have a high oil contact angle and excellent impact resistance, which can significantly improve the oil collection performance of the radial oil-collecting ring.

[0187] Comparative Example 1 shows that the honeycomb-shaped pit buffer array formed on the radial oil-collecting ring surface by laser treatment not only improves the coating's impact resistance but also increases the oil contact angle. Comparative Example 2 shows that the diameter of the polygonal pits affects the oil contact angle attenuation rate; the coating exhibits the best impact resistance within the maximum diameter range of 80-100 μm specified in this invention. Comparative Example 3 shows that the depth of the polygonal pits and the grid height significantly affect the oil contact angle attenuation rate; the coating exhibits the best impact resistance within the specified depth range of 20-30 μm and grid height range of 6-10 μm. Comparative Examples 4 and 5 show that plasma treatment effectively improves the coating's oleophobic effect, and multiple sprays result in a smooth and uniform coating surface, giving the coating excellent oleophobic properties.

[0188] Other components and operations of the method for preparing a superoleophobic coating for a radial oil-collecting ring of an aircraft engine according to an embodiment of the present invention are known to those skilled in the art and will not be described in detail here.

[0189] In the description of this specification, references to terms such as "embodiment," "example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0190] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for preparing a superoleophobic coating for a radial oil-collecting ring in an aircraft engine, characterized in that, Includes the following steps: (1) Clean the radial oil collection ring; (2) The surface of the radial oil collection ring is laser-treated, and the surface of the radial oil collection ring has a honeycomb-shaped pit buffer array composed of multiple polygonal pits, and each polygonal pit has a grid structure. (3) Apply coating to the radial oil-collecting ring after laser treatment; (4) Plasma activation is performed on the radial oil-collecting ring with the coating to generate hydroxyl groups on the coating surface; (5) Immerse the plasma-activated radial oil-collecting ring in a fluorosiloxane solution, remove and dry it to obtain a radial oil-collecting ring with a superoleophobic coating. In step (2), the depth of the polygonal pit is 20-30μm, the maximum diameter is 80-100μm, and the distance between two adjacent polygonal pits is less than 10μm. The mesh structure is located at the bottom of the polygonal pit, and the height of the mesh structure is 6~10μm, with a mesh spacing of about 5μm; Step (3) includes: Preheat the radial oil-collecting ring to be sprayed; The preheated radial oil-retaining ring is first coated, and then baked. Apply a second coat to the radial oil-collecting ring, then bake it. Repeat this process at least three times. Finally, the radial oil-collecting ring is dried at room temperature.

2. The method according to claim 1, characterized in that, The sidewalls of the polygonal recess include a vertical wall and an inclined wall, wherein the bottom edge of the inclined wall is connected to the top edge of the vertical wall. The angle between the inclined wall and the vertical wall is 150-160°.

3. The method according to claim 1, characterized in that, The coating comprises hydrophobic silica nanoparticles, tetrahydrofuran, isopropanol, and methylphenyl silicone resin. The preheating temperature for the radial oil-retaining ring to be sprayed is 50-70℃, the baking temperature after spraying the radial oil-retaining ring is 50-70℃, and the baking temperature after the last spray is 40℃.

4. The method according to claim 3, characterized in that, The preparation method of the coating includes: Hydrophobic silica nanoparticles were added to a mixture of tetrahydrofuran and isopropanol and then ultrasonically dispersed. Methylphenyl silicone resin was then added and ultrasonically dispersed again. The volume ratio of tetrahydrofuran to isopropanol is 2:3, and the mass ratio of the hydrophobic silica nanoparticles to the methylphenyl silicone resin is (4~5):

1.

5. The method according to claim 1, characterized in that, The coating thickness is 16~20μm, and the thickness of each spray is 4~5μm.

6. The method according to claim 1, characterized in that, In step (4), the radial oil-collecting ring that has completed step (3) is placed in air at room temperature for more than 2 hours, and then the radial oil-collecting ring is placed in a plasma instrument and plasma-treated for 40 to 60 minutes under oxygen conditions.

7. The method according to claim 1, characterized in that, In step (5), the radial oil-collecting ring that has completed step (4) is immersed in a 5wt% fluorosiloxane ethanol solution for 10-15 minutes. Remove and dry at room temperature to obtain a superoleophobic coating.

8. The method according to claim 7, characterized in that, The fluorosiloxane is one or both of heptadecafluorodecyltriethoxysilane and tridecafluorooctyltriethoxysilane.

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