A method for compounding a superhydrophobic coating on the surface of a stainless steel array

Abstract

The present invention relates to the technical field of stainless steel surface treatment, and discloses a method for compounding a superhydrophobic coating on the surface of a stainless steel array, including: Step 1, processing a photoresist structure on the surface of a substrate material to obtain a substrate containing the photoresist structure; Step 2, etching the substrate containing the photoresist structure successively in an HF solution and a mixed solution of HF and H2O2 to obtain a substrate with an array structure; Step 3, removing the surface photoresist of the substrate with the array structure to obtain the surface of the substrate material array; Step 4, spraying a mixed solution of low-density polyethylene micron particles, PTFE nano particles and absolute ethanol on the surface of the substrate material array, and drying to obtain a substrate material with a compound superhydrophobic coating sprayed on the surface; Step 5, sintering the obtained substrate material and then cooling to obtain the compound superhydrophobic coating. The compound superhydrophobic coating prepared by the method of the present invention has excellent hydrophobicity, corrosion resistance and wear resistance.

Description

Technical Field

[0001] The invention relates to the technical field of stainless steel surface treatment, and in particular to a method for compounding a super-hydrophobic coating on the surface of a stainless steel array. Background Art

[0002] When an aircraft flies in a high-altitude, low-temperature, and high-humidity environment, the surface is very prone to ice, which seriously affects the flight safety of the aircraft. The complex and changeable ice formation directly changes the lift shape of the wing, seriously affecting the aerodynamic characteristics of the aircraft, causing a series of hazards such as reduced lift, increased drag, early stall angle of attack, and reduced maximum available lift coefficient, which greatly limits the transportation capacity of aircraft, especially civil aircraft, and causes a waste of transportation resources. To this day, the problem of aircraft icing is still an important issue that needs to be solved in the aviation field.

[0003] In recent years, bionic super-hydrophobic materials have emerged and developed rapidly. Micro-nanostructured super-hydrophobic surfaces have excellent dynamic super-hydrophobic properties, ice delay properties and ice layer adhesion properties due to their low surface energy and rough microstructures. They are considered to be an ideal ultra-low energy consumption anti-icing / de-icing technology with good application prospects. However, during the high-altitude flight of aircraft, the micro-nanostructure, one of the anti-icing factors of the super-hydrophobic surface, is easily damaged, thereby changing the wetting state of the droplets on the surface and ultimately destroying the anti-icing properties of the surface. Therefore, research on the long-term anti-icing performance and environmental stability enhancement of super-hydrophobic surfaces is particularly important. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, an object of the present invention is to provide a method for composite super-hydrophobic coating on the surface of a stainless steel array.

[0005] To achieve the above objectives, the present invention adopts the following technical solutions:

[0006] A method for compounding a super-hydrophobic coating on the surface of a stainless steel array comprises the following steps:

[0007] Step 1, processing a photoresist structure on the surface of a substrate material to obtain a substrate containing the photoresist structure;

[0008] Step 2, etching the substrate containing the photoresist structure in HF solution and a mixed solution of HF and H2O2 in sequence to obtain a substrate with an array structure;

[0009] Step 3, removing the surface photoresist of the substrate having the array structure to obtain the substrate material array surface;

[0010] Step 4, spraying a mixture of low-density polyethylene microparticles, PTFE nanoparticles and anhydrous ethanol onto the surface of the substrate material array, and drying to obtain a substrate material with a composite super-hydrophobic coating sprayed on the surface;

[0011] Step 5: Sinter and then cool the substrate material obtained in Step 4 to obtain a composite superhydrophobic coating.

[0012] Preferably, before Step 1, the substrate material is pretreated, and the pretreatment includes grinding, degreasing and cleaning the substrate material, and then drying for standby.

[0013] Preferably, Step 1 uses a maskless lithography technology based on a digital micromirror device to process a photoresist structure on the surface of the substrate material.

[0014] Preferably, the substrate material is stainless steel.

[0015] Preferably, in Step 1, the area where the photoresist remains is a square area of 80×80 μm.

[0016] Preferably, the array structure is a micro-scale square column with a height of 40 μm and a side length of 80 μm, and the spacing between the square columns is 60 μm.

[0017] Preferably, in Step 4, first prepare an anhydrous ethanol-based aqueous concentrate of PTFE nanoparticles as a dispersion medium, and then add low-density polyethylene micron particles.

[0018] In a preferred embodiment of the present application, an anhydrous ethanol-based aqueous concentrate of 24-60 g / L of PTFE nanoparticles is prepared as a dispersion medium, and 30 g / L of low-density polyethylene micron particles are added.

[0019] Preferably, in Step 2, in the mixed solution of HF and H2O2, the concentration of HF is 2-8 mol / L, and the concentration of H2O2 is 0.2-0.8 mol / L.

[0020] Preferably, Step 2 further includes: after etching in the mixed solution of HF and H2O2, cleaning in a 50 wt% nitric acid solution to obtain a substrate with a dense and stable structure.

[0021] Preferably, in Step 3, the substrate with the array structure is placed in an alcohol solution at 70-90 °C to heat and remove the photoresist.

[0022] The present invention further finds that after two-step etching and then heating in an alcohol solution at 70-90 °C to remove the photoresist, not only can the photoresist be removed more cleanly, but also the time used for the photoresist removal step can be shortened, and the preparation efficiency can be improved. Removing the photoresist in an alcohol solution at room temperature has a poor removal effect. And using acetone to remove the photoresist has a good removal effect, but acetone has a large evaporation amount and has a certain risk of combustion and explosion.

[0023] Further preferably, the substrate with the array structure is placed in an alcohol solution at 75-85 °C to heat and remove the photoresist to obtain a surface with a micro-scale regular square column array structure; more preferably, heat for more than 2 h.

[0024] Preferably, the alcohol solution is an ethanol solution.

[0025] Preferably, in step 4, the spraying pressure is 2 MPa, and the spraying treatment is carried out using a spray gun at a constant speed of 2 cm / s. One cycle is from left to right, and after four cycles, the spraying is uniform, and the coating thickness is 40 - 60 μm.

[0026] Preferably, in step 4, it also includes that the sprayed sample is dried in an electrothermal blast drying oven at 65°C.

[0027] Preferably, in step 5, the temperature of the sintering treatment is 200°C, and the heat preservation time is 30 min.

[0028] Preferably, in step 5, the cooling temperature is 25°C.

[0029] Preferably, the particle size of the PTFE nanoparticles is 200 nm, and the particle size of the low - density polyethylene particles is 25 μm.

[0030] Preferably, in step 4, the composite resin slurry solution is stirred for 20 min and ultrasonically treated for 30 min before spraying.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) The present invention utilizes PTFE nanoparticles to adhere to the surface of relatively larger - sized polyethylene particles, and at the same time mechanically stirs the composite slurry to achieve uniform distribution of PTFE particles inside the composite slurry. After spraying and sintering, the polyethylene particles are bonded to each other to achieve densification of the coating. The un - melted PTFE nanoparticles act as low - surface - energy nanostructures, and finally a composite super - hydrophobic coating with low - surface - energy micro - nano structures is prepared. This composite super - hydrophobic coating has excellent hydrophobicity, corrosion resistance and wear resistance.

[0033] (2) According to the solid and molten state characteristics of PTFE and PE, as well as their dispersion in absolute ethanol, the present invention can form a micro - nano structure polymer coating on the stainless - steel micron - scale array structure during the spraying process. Through subsequent sintering treatment, the distribution of the two polymers is further made uniform, the coating density is increased, and the overall structural mechanical properties are improved, enabling the surface to withstand high - speed droplet and particle impacts and maintaining the structural integrity, which has more obvious advantages compared with a single flat resin component.

[0034] (3) Compared with the low surface energy modification technology on the surface layer of metal-based superhydrophobic surfaces, the superhydrophobic coating obtained by the blending technology of PTFE nanoparticles and PE resin in the present invention has low surface energy substances distributed in the overall structure. The newly exposed surface after abrasion of the surface layer components still has low surface energy nanoparticles distributed, meeting the requirements for surface superhydrophobicity and showing more excellent durability.

[0035] (4) The method for compounding a superhydrophobic coating on the surface of a stainless steel array involved in the present invention has a simple process, low cost, and is not limited by the size and shape of the metal surface. It can be used for different curved surfaces of aircraft in various complex environments, and is of great significance for the technical development of long-term anti-icing on the aircraft surface. Brief Description of the Drawings

[0036] Figure 1 is the process flow chart of a method for compounding a superhydrophobic coating on the surface of a stainless steel array involved in the present invention;

[0037] Figure 2 A is the three-dimensional topography map of the lithographed surface in Example 3, and B is the microscopic optical image of the compound superhydrophobic coating;

[0038] Figure 3 is the water droplet diagram on the surface of the compound superhydrophobic coating in the embodiment of the present invention;

[0039] Figure 4 is the schematic diagram of the wear resistance degree of the compound superhydrophobic coating in the embodiment of the present invention;

[0040] Figure 5 is the schematic diagram of the acid and alkali resistance degree of the compound superhydrophobic coating in the embodiment of the present invention;

[0041] Figure 6 is the structural diagram of the de-icing experimental device involved in the present invention;

[0042] Figure 7 is the schematic diagram of the change in ice adhesion strength under de-icing cycles of the compound superhydrophobic coating in the embodiment of the present invention;

[0043] Reference numerals in the drawings: 1 is the test bench, 2 is the slide rail, 3 is the dynamometer, 4 is the stainless steel substrate to be tested with the compound superhydrophobic coating, 5 is the ice layer, and 6 is the fixture. Detailed Embodiments

[0044] The present invention will be described in detail below with reference to specific embodiments. It should be noted that the following embodiments are only further descriptions of the present invention, but the protection scope of the present invention is not limited to the following embodiments.

[0045] The following Examples 1-3 are elaborated in detail using 304 stainless steel commonly used in daily life as samples, and the stainless steel can be purchased commercially.

[0046] Example 1

[0047] As Figure 1 shown, a method for preparing a composite superhydrophobic coating on the surface of a stainless steel array includes the following steps:

[0048] S1. Pretreat the stainless steel surface

[0049] Polishing: Laser cut the stainless steel sample into a 30*30 mm sample, and polish it successively with 600-mesh, 1000-mesh, 2000-mesh, and 5000-mesh SiC sandpaper.

[0050] In this example, a 0.2-mm-thick 304 stainless steel sheet is used as the base material. 304 stainless steel has excellent mechanical properties, which are sufficient to withstand the harsh environment during high-altitude flight of an aircraft. At the same time, the thin sheet design effectively reduces the weight gain of the aircraft.

[0051] Degreasing: After polishing, put the stainless steel sample into anhydrous ethanol and acetone successively for ultrasonic cleaning for 10 minutes each time. After taking it out, blow it dry with nitrogen to remove the surface grease and debris.

[0052] S2. Use maskless lithography technology based on a digital micromirror device to process a photoresist structure on the surface of the stainless steel sample to obtain a substrate containing a photoresist structure;

[0053] In this example, AR-N 4400 05 negative photoresist is used as the mask for wet etching to prepare a patterned structure. Specifically, it is divided into 5 steps:

[0054] ① Coating: Spin-coat a layer of photoresist on the silicon wafer surface with a spin coater at a speed of 4 krpm / min for 60 s;

[0055] ② Pre-baking: Place the silicon wafer coated with photoresist on a hot plate at 85 °C and bake for 60 s;

[0056] ③ Exposure: Use a femtosecond laser two-photon micro-nano processing system to process the photoresist structure. In this experiment, a 50x lens is used, the DMD mask pattern is square, the designed DMD size is 1024×768 pixels, and the side line width of the designed mask pattern is 65.8 pixel;

[0057] ④ Post-baking: Place the exposed sample on an electric hot plate at 85 °C and bake for 60 s;

[0058] ⑤ Development: Cool the sample processed in step ④ to room temperature and immerse it successively in the developer and deionized water.

[0059] The area where the photoresist remains is a square area of 80×80 μm; the array structure is a micro-scale square column with a height of 40 μm and a side length of 80 μm, and the spacing between the square columns is 60 μm.

[0060] S3. Etching: The substrate with the photoresist structure is etched in a 4.8 mol / L HF solution for 2 min, and then etched in a mixed solution of 4.8 mol / L HF and 0.4 mol / L H2O2 for 10 min. After the etching is completed, the sample is rinsed with deionized water.

[0061] Passivation: The sample is immersed in a 50 wt% nitric acid solution for 30 min.

[0062] Cleaning: The sample is rinsed with deionized water, then ultrasonically cleaned in anhydrous ethanol and acetone for 10 min each, taken out and dried with nitrogen for standby.

[0063] S4. Removing photoresist: The passivated sample is placed in an ethanol solution at 80 °C, taken out after water bath heating for 2 h, rinsed with a large amount of anhydrous ethanol, dried for standby, and thus a stainless steel sheet with a square (80 μm) pattern array on the surface is obtained.

[0064] S5. Spraying

[0065] Preparing composite slurry: Prepare an anhydrous ethanol solution of a 24 g / L PTFE nanoparticle aqueous concentrate as a dispersion medium, and add 30 g / L low-density polyethylene microparticles; stir for 20 min and ultrasonicate for 30 min before spraying.

[0066] Spraying composite superhydrophobic coating: Using an air pump as the air flow source, the spraying pressure is 2 MPa. The spraying process is carried out using a spray gun at a constant speed of 2 cm / s, with one cycle from left to right, and after four cycles, the spraying is uniform, the coating thickness is 40 - 60 μm, and the sprayed sample is dried at 65 °C.

[0067] S6. Sinter the stainless steel sample with the composite superhydrophobic coating sprayed on its surface at 200 °C for 30 min, and then cool it to room temperature at 25 °C to obtain the composite superhydrophobic coating.

[0068] Example 2

[0069] A method for preparing a composite superhydrophobic coating on the surface of a stainless steel array, comprising the following steps:

[0070] S1. Pretreating the stainless steel surface

[0071] Polishing: Laser cut the stainless steel sample into a 30*30 mm sample, and polish it successively with 600-mesh, 1000-mesh, 2000-mesh, and 5000-mesh SiC sandpapers.

[0072] Degreasing: After polishing, the stainless steel sample is ultrasonically cleaned in anhydrous ethanol and acetone successively, with each cleaning for 10 min, taken out and dried with nitrogen to remove surface grease and debris.

[0073] S2. Use maskless lithography technology based on digital micromirror device to process a photoresist structure on the surface of a stainless-steel sample, and obtain a substrate with a photoresist structure.

[0074] In this embodiment, AR-N 4400 05 negative photoresist is used as a mask for wet etching to prepare a patterned structure. Specifically, it is divided into 5 steps:

[0075] ① Coating: Spin-coat a layer of photoresist on the surface of the silicon wafer with a spin coater at a speed of 4 krpm / min for 60 s.

[0076] ② Pre-baking: Place the silicon wafer coated with photoresist on a hot plate at 85 °C and bake for 60 s.

[0077] ③ Exposure: Use a femtosecond laser two-photon micro-nano processing system to process the photoresist structure. In this experiment, a 50x lens is used, the DMD mask pattern is square, the designed DMD size is 1024×768 pixels, and the side line width of the designed mask pattern is 65.8 pixel.

[0078] ④ Post-baking: Place the exposed sample on an electric hot plate at 85 °C and bake for 60 s.

[0079] ⑤ Development: Cool the sample processed in step ④ to room temperature, and immerse it in the developer and deionized water in sequence.

[0080] S3. Etching: Immerse the substrate with the photoresist structure in a 4.8 mol / L HF solution for 2 min, and then in a mixed solution of 4.8 mol / L HF and 0.4 mol / L H2O2 for 10 min. After etching, rinse the sample with deionized water.

[0081] Passivation: Immerse the sample in a 50 wt% nitric acid solution for 30 min.

[0082] Cleaning: Rinse the sample with deionized water, then ultrasonically clean it in anhydrous ethanol and acetone for 10 min each. After taking it out, dry it with nitrogen for standby.

[0083] S4. Remove photoresist: Place the passivated sample in an ethanol solution at 80 °C, take it out after water bath heating for 2 h, rinse it with a large amount of anhydrous ethanol, and dry it for standby, then obtain a stainless-steel sheet with a square (80 μm) pattern array on the surface.

[0084] S5. Spraying

[0085] Prepare composite slurry: Prepare an anhydrous ethanol solution of a 48 g / L PTFE nanoparticle aqueous concentrate as a dispersion medium, and add 30 g / L low-density polyethylene micron particles; stir for 20 min and ultrasonically treat for 30 min before spraying.

[0086] Spraying of composite superhydrophobic coating: Using an air pump as the air flow source, the spraying pressure is 2 MPa. The spraying process uses a spray gun to move from left to right at a constant speed of 2 cm / s for one cycle, and after four cycles, the spraying is uniform. The coating thickness is 40 - 60 μm, and the sprayed sample is dried at 65 °C.

[0087] S6. Sinter the stainless - steel sample with the composite superhydrophobic coating sprayed on its surface at 200 °C for 30 min, and then cool it to room temperature at 25 °C to obtain the composite superhydrophobic coating.

[0088] Example 3

[0089] A method for preparing a composite superhydrophobic coating on the surface of a stainless - steel array, comprising the following steps:

[0090] S1. Pretreat the stainless - steel surface

[0091] Grinding: Laser - cut the stainless - steel sample into a 30 * 30 mm sample, and polish it successively with 600 - mesh, 1000 - mesh, 2000 - mesh, and 5000 - mesh SiC sandpaper.

[0092] Degreasing: After grinding, put the stainless - steel sample into anhydrous ethanol and acetone successively for ultrasonic cleaning for 10 min each time. After taking it out, blow it dry with nitrogen to remove surface grease and debris.

[0093] S2. Use a maskless lithography technology based on a digital micromirror device to process a photoresist structure on the surface of the stainless - steel sample to obtain a substrate containing a photoresist structure;

[0094] In this example, AR - N 4400 05 negative photoresist is used as the mask for wet etching to prepare a patterned structure. Specifically, it is divided into 5 steps:

[0095] ① Coating: Use a spin coater to coat a layer of photoresist on the silicon wafer surface at a rotation speed of 4 krpm / min for 60 s;

[0096] ② Pre - baking: Place the silicon wafer coated with photoresist on a hot plate at 85 °C and bake for 60 s;

[0097] ③ Exposure: Use a femtosecond laser two - photon micro - nano processing system to process the photoresist structure. In this experiment, a 50 - fold lens is used, the DMD mask pattern is square, the designed DMD size is 1024×768 pixels, and the side - length line width of the designed mask pattern is 65.8 pixel;

[0098] ④ Post - baking: Place the exposed sample on an electric hot plate at 85 °C and bake for 60 s;

[0099] ⑤ Development: Cool the sample processed in step ④ to room temperature and immerse it successively in the developer and deionized water.

[0100] S3. Etching: Immerse the substrate with the photoresist structure successively in a 4.8 mol / L HF solution for 2 min and then in a mixed solution of 4.8 mol / L HF and 0.4 mol / L H2O2 for 10 min. After etching, rinse the sample with deionized water.

[0101] Passivation: Immerse the sample in a 50 wt% nitric acid solution for 30 min.

[0102] Cleaning: Rinse the sample with deionized water, then ultrasonically clean it in anhydrous ethanol and acetone for 10 min each. After taking it out, dry it with nitrogen for standby.

[0103] S4. Removing photoresist: Place the passivated sample in an ethanol solution at 80 °C, take it out after water bath heating for 2 h, rinse it with a large amount of anhydrous ethanol, and dry it for standby, thus obtaining a stainless steel sheet with a square (80 μm) pattern array on the surface.

[0104] S5. Spraying

[0105] Preparing composite slurry: Prepare an anhydrous ethanol solution of a 60 g / L PTFE nanoparticle aqueous concentrate as the dispersion medium and add 30 g / L low-density polyethylene microparticles; stir for 20 min and ultrasonicate for 30 min before spraying.

[0106] Spraying composite superhydrophobic coating: Use an air pump as the air flow source, with a spraying pressure of 2 MPa. The spraying process is to use a spray gun, at a constant speed of 2 cm / s, from left to right as one cycle, and after four cycles, spray evenly. The coating thickness is 40 - 60 μm, and the sprayed sample is dried at 65 °C.

[0107] S6. Sinter the stainless steel sample with the composite superhydrophobic coating sprayed on its surface at 200 °C for 30 min, and then cool it to room temperature at 25 °C to obtain the composite superhydrophobic coating.

[0108] Performance testing

[0109] 1. Hydrophobicity testing

[0110] Take the composite superhydrophobic coating prepared in Example 3; as Figure 2 shown, the surface water droplet diagram of the composite superhydrophobic coating prepared in Example 3 indicates that the composite superhydrophobic coating prepared by the method of Example 3 has a tight combination with the stainless steel substrate, a uniform and complete surface. It can be seen from Figure 3 this that the surface of this coating has excellent superhydrophobicity, with a static contact angle of the liquid droplet of 162 ± 2° and a rolling angle of 5 ± 1°.

[0111] 2. Wear Resistance Performance Test

[0112] Take the composite superhydrophobic coating prepared in Example 3. The test results are as follows Figure 4 shown. Select 240-mesh SiC sandpaper as the wear test medium. Invert the sample on the sandpaper and place a 250-g weight on the top. Drag the sample forward for 10 cm, turn 90° and then move forward for 10 cm as one wear test cycle. After the test, measure the static contact angle of the surface droplets.

[0113] The results show that: the coating surface prepared by the method of this example has superhydrophobicity after being worn. Compared with the traditional metal-based micro-nano structured superhydrophobic surface, it can resist up to 10 cycles and has good wear resistance performance.

[0114] The coating prepared by the method of the present invention has a strong overall structure, a uniform and complete surface, and excellent wear resistance performance.

[0115] 3. Acid and Alkali Resistance Performance Test

[0116] Take the PTFE superhydrophobic coating prepared in Example 3. Immerse the sample in acid and alkali solutions with pH values of 1, 3, 5, 7, 9, 11, and 13 for 12 hours. After rinsing with deionized water and drying, measure the static contact angle of the surface droplets. The results are as follows Figure 5 shown. The coating has superhydrophobicity in alkali solutions, but the hydrophobicity decreases in strong acid solutions. At the same time, compared with the traditional metal-based micro-nano structured superhydrophobic surface, the decrease in hydrophobicity of the composite superhydrophobic coating is smaller, showing good acid and alkali resistance performance.

[0117] The composite superhydrophobic coating prepared by the method of the present invention has a strong overall structure, a uniform and complete surface, and excellent acid and alkali resistance performance.

[0118] 4. Anti-icing Performance Test

[0119] Take the PTFE superhydrophobic coating prepared in Example 3. Measure the external force required to remove the ice layer through a self-made ice adhesion experimental device. One measurement of the external force is one cycle.

[0120] Invert the sample on the top of a plastic open square column filled with deionized water. The square opening size is 10*10 mm. The hydrophobic surface of the sample contacts the water. Put the sample together with the square column into a -20°C environment and freeze for 12 hours. Then, remove it and place it in a -10°C environment. Use a thrust meter to push the ice cube horizontally along the side of the square column from the surface and measure the maximum thrust required. For the experimental device, see Figure 6 , 1 is the test bench, the fixture 6 fixes the stainless steel substrate 4 coated with the composite superhydrophobic coating. The forward movement of the slide rail 2 drives the dynamometer 3 to push the ice layer 5, and record the stress when the ice layer breaks. The results are as follows Figure 7As shown, the results indicate that compared with the stainless-steel surface, the ice adheres weakly to the coated surface, and only a very small thrust is required to remove the ice from the coated surface. At the same time, after 20 cycles, the adhesion strength is still much lower than that of the stainless-steel surface. The composite superhydrophobic coating exhibits good anti-icing performance. The composite superhydrophobic coating prepared by the present invention has a solid overall structure, a uniform and complete surface, and excellent anti-icing performance.

[0121] The method of this application uses photolithography to control the chemical etching path and prepares regular micron-scale square-column structures on the surface of a stainless-steel material thin film. Taking the square-column substrate as the hydrophobic structure support, the material of the hydrophobic structure itself uses a hybrid resin to further enhance stability; low surface energy particles are doped inside the polyethylene to ensure that the structure can still function even if damaged, breaking through the technical bottleneck of the insufficient mechanical / environmental durability of the micro-nano structured superhydrophobic surface, improving the anti-icing ability of the superhydrophobic metal thin film, and promoting the engineering application of the superhydrophobic metal thin film in the field of aircraft anti-icing and de-icing.

[0122] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various deformations or modifications within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A method for compounding a superhydrophobic coating on the surface of a stainless steel array, characterized in that, It includes the following steps: Step 1, process a photoresist structure on the surface of a substrate material to obtain a substrate containing the photoresist structure; The substrate material is stainless steel; Step 2, etch the substrate containing the photoresist structure successively in an HF solution and a mixed solution of HF and H2O2 to obtain a substrate with an array structure; The array structure is a micron-scale square column with a height of 40 μm and a side length of 80 μm, and the spacing between the square columns is 60 μm; Step 3, remove the surface photoresist of the substrate with the array structure to obtain the surface of the substrate material array; Step 4, spray a mixed solution of low-density polyethylene micron particles, PTFE nano particles and absolute ethanol on the surface of the substrate material array, and dry it to obtain a substrate material with a composite superhydrophobic coating sprayed on the surface; Step 5, sinter the substrate material obtained in Step 4 and then cool it to obtain a composite superhydrophobic coating; The temperature of the sintering treatment is 200 °C, and the heat preservation time is 30 min.

2. The method for compounding a superhydrophobic coating on the surface of a stainless steel array according to claim 1, characterized in that, Before Step 1, pre-treat the substrate material. The pre-treatment includes grinding, degreasing and cleaning the substrate material, and then drying it for standby.

3. The method for compounding a superhydrophobic coating on the surface of a stainless steel array according to claim 1, wherein Step 1 uses a maskless lithography technology based on a digital micromirror device to process a photoresist structure on the surface of the substrate material.

4. The method for compounding a superhydrophobic coating on the surface of a stainless steel array according to claim 1, wherein, In Step 1, the area where the photoresist remains is a square area of 80×80 μm.

5. The method for compounding a superhydrophobic coating on the surface of a stainless steel array according to claim 1, wherein In Step 4, first configure absolute ethanol of a PTFE nano particle aqueous concentrate as a dispersion medium, and then add low-density polyethylene micron particles.

6. The method for compositing a superhydrophobic coating on the surface of a stainless steel array according to claim 1, characterized in that, Step 2 also includes: after etching in the mixed solution of HF and H2O2, cleaning in a 50wt% nitric acid solution.

7. The method for compounding a superhydrophobic coating on the surface of a stainless steel array according to claim 1, wherein In Step 3, place the substrate with the array structure in an alcohol solution at 70-90 °C to heat and remove the photoresist.

8. The method for compositing a superhydrophobic coating on the surface of a stainless steel array according to claim 7, characterized in that, Place the substrate with the array structure in an alcohol solution at 75-85 °C to heat and remove the photoresist; the alcohol solution is an ethanol solution.

9. The method for compositing a superhydrophobic coating on the surface of a stainless steel array according to claim 1, wherein The particle size of the PTFE nano particles is 200 nm, and the particle size of the low-density polyethylene particles is 25 μm.

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