A robust super-hydrophobic surface for low-temperature steel and a preparation method and application thereof

Abstract

The present application relates to a kind of solid super-hydrophobic surface for low-temperature steel and its preparation method and application.The preparation method includes the following steps: laser ablation treatment is carried out on the surface of low-temperature steel after pretreatment, and then heat treatment is carried out to obtain solid super-hydrophobic low-temperature steel surface.The hydrophobic surface prepared has staggered inverted cone-shaped armor structure, which includes inverted cone-shaped pits and nanoparticles on the surface of the pits, and the inverted cone-shaped pits are periodically staggered.Compared with the prior art, the present application provides good super-hydrophobicity and mechanical durability for the surface of marine low-temperature steel, and can meet the requirements of ice resistance and mechanical durability of low-temperature steel in polar ship applications.

Description

Technical Field

[0001] This invention belongs to the field of surface engineering technology of metallic materials, and in particular relates to a robust superhydrophobic surface for low-temperature steel, its preparation method and application. Background Technology

[0002] Superhydrophobic metallic surfaces possess excellent corrosion resistance, self-cleaning properties, and anti-icing / de-icing capabilities, making them highly promising for applications in automotive, medical, aerospace, marine, and oil pipeline transportation. However, in practical applications, superhydrophobic metallic surfaces inevitably suffer from friction, impact, and scratches, leading to surface damage and loss of protective function. Particularly in polar marine applications, higher performance in mechanical durability is required. Furthermore, achieving superhydrophobic surfaces necessitates a rough structure and low surface energy. Therefore, chemical modification is often employed in the preparation of superhydrophobic metallic surfaces. However, chemical modification suffers from complex operations and the use of toxic chemical modifiers. In practical applications, it damages the ecological environment, limiting the application of superhydrophobic metallic surfaces in polar waters. Therefore, developing a simple and environmentally friendly preparation method to manufacture robust superhydrophobic metallic surfaces with excellent mechanical durability has become a current research focus.

[0003] To overcome the problem of poor mechanical durability of superhydrophobic metal surfaces failing to meet practical application requirements, numerous researchers have enhanced the mechanical durability of superhydrophobic surfaces by designing surface structures with excellent robustness, using high-strength hydrophobic materials, and strengthening interfacial adhesion. Although some progress has been made in preparing robust superhydrophobic metal surfaces, most research strategies have only limited impact on improving their robustness. Faced with this challenge, the concept of "armor" structures has emerged, protecting hydrophobic nanostructures from mechanical wear and achieving a substantial breakthrough in improving the mechanical durability of superhydrophobic metal surfaces. However, current preparation processes are complex, expensive, and lack versatility, requiring not only custom-designed molds but also the subsequent filling with hydrophobic materials. Therefore, a simple, flexible, and robust superhydrophobic metal surface preparation method remains needed.

[0004] Laser processing is a simple, efficient, flexible, and high-precision technology that has been widely applied in advanced manufacturing, 3D printing, and surface modification. It allows for the fabrication of micro- and nano-structures on metal surfaces such as copper, aluminum, titanium, and stainless steel without any chemical treatment, providing a flexible and environmentally friendly way to create various superhydrophobic metal surfaces with excellent anti-icing properties and mechanical durability. However, cryogenic steel has received relatively little attention. Considering the harsh operating environments of polar cryogenic marine steel, obtaining robust superhydrophobic surfaces with good wear resistance and anti-icing properties is highly necessary.

[0005] Therefore, in order to solve the huge challenges of icebreaking and ice prevention faced by cryogenic steel in polar ship applications, it is still necessary to develop superhydrophobic surfaces for cryogenic steel. Summary of the Invention

[0006] The purpose of this invention is to provide a robust superhydrophobic surface for low-temperature steel, its preparation method and application, to meet the requirements of anti-icing performance and mechanical durability in polar marine applications.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] A method for preparing a robust superhydrophobic surface for low-temperature steel includes the following steps:

[0009] A robust, superhydrophobic low-temperature steel surface can be obtained by laser ablation treatment on the pretreated low-temperature steel surface followed by heat treatment.

[0010] Furthermore, the pretreatment includes cleaning and polishing.

[0011] Furthermore, the cleaning process uses anhydrous ethanol.

[0012] Furthermore, the cleaning is performed under ultrasound for 5-10 minutes.

[0013] Furthermore, the polishing is performed using metallographic sandpaper.

[0014] Furthermore, the polishing process employs gradient polishing, preferably using 180#, 600#, 1200#, and 2000# metallographic sandpaper in sequence.

[0015] Furthermore, the low-temperature steel is preferably FH36.

[0016] Furthermore, the laser ablation process is performed on a path of uniformly arranged concentric circles, wherein the outer circle has a diameter of 25-35 μm, the inner circle has a diameter of 10-20 μm, and the distance between the centers of the concentric circles is 45-55 μm.

[0017] Furthermore, the concentric circles are arranged at equal intervals and do not intersect each other.

[0018] Furthermore, the outer and inner circles are subjected to laser ablation treatment alternately.

[0019] Furthermore, one cycle consists of one laser processing of the outer circle followed by two processing of the inner circle, and the alternating processing cycles are 1-7 times.

[0020] Furthermore, the laser ablation treatment employs an ultraviolet picosecond laser.

[0021] Furthermore, the diameter of the laser spot is 10-15 μm, preferably 10 μm.

[0022] Furthermore, the laser power is 2-3W.

[0023] Furthermore, the laser frequency is 1000-2000kHz.

[0024] Furthermore, the laser operates at a speed of 50-100 mm / s.

[0025] Furthermore, the heat treatment is a vacuum heat treatment.

[0026] Furthermore, the vacuum level is preferably 1 bar.

[0027] Furthermore, the heat treatment temperature is 100-150℃.

[0028] Furthermore, the heat treatment time is 3-6 hours.

[0029] The present invention also provides a robust superhydrophobic surface for low-temperature steel prepared by the above method.

[0030] Furthermore, the superhydrophobic surface has an alternating inverted conical armor structure.

[0031] Furthermore, the inverted conical armor structure includes periodically staggered inverted conical recesses and nanoparticles on the surface of the recesses. The staggered arrangement of the inverted conical armor structure provides excellent superhydrophobicity and mechanical durability to the marine low-temperature steel surface.

[0032] The present invention also provides an application of a robust superhydrophobic surface for low-temperature steel in polar vessels.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] (1) This invention uses picosecond laser processing technology to laser ablation treatment on the surface of low-temperature steel to finally construct a robust superhydrophobic surface with an armor structure on the surface of low-temperature steel. The staggered inverted conical armor structure provides good superhydrophobicity and mechanical durability for the surface of marine low-temperature steel, which can meet the requirements of ice resistance and mechanical durability of low-temperature steel in polar ship applications.

[0035] (2) The processing of the present invention is simple and does not use any toxic or harmful chemical reagents or chemical processes, making the process simple and environmentally friendly.

[0036] (3) The robust superhydrophobic surface prepared by the present invention has an alternating inverted conical armor structure, which balances the hydrophobicity and mechanical stability of the low-temperature steel surface, providing good superhydrophobicity and mechanical durability for marine low-temperature steel surfaces. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the process flow for the preparation method of the present invention.

[0038] Figure 2 This is a schematic diagram of the processing path for laser ablation treatment in Embodiment 1 of the present invention.

[0039] Figure 3 The image shows a scanning electron microscope (SEM) image of the FH36 low-temperature steel in Comparative Example 1 that has not undergone laser ablation treatment.

[0040] Figure 4 Scanning electron microscope images (50 μm and 1 μm) of the robust superhydrophobic surface of low-temperature steel prepared in Example 1.

[0041] Figure 5 The images show (a) a three-dimensional profile and (b) a 2D dimension scan of the marine cryogenic steel surface obtained by seven cycles of laser etching in Example 1.

[0042] Figure 6 The results are for the water droplet contact angle test of the robust superhydrophobic surface of low-temperature steel prepared in (a) Comparative Example 1 and (b) Example 1.

[0043] Figure 7 The results are from the sandpaper abrasion test on the surface of the robust marine low-temperature steel prepared in Examples 1-3.

[0044] Figure 8 The image shows the SEM image of the robust superhydrophobic surface of low-temperature steel prepared in Example 1 after 10 sandpaper abrasion cycles.

[0045] Figure 9 The image shows a comparison of the water droplet freezing process on the robust superhydrophobic surface of low-temperature steel prepared in Example 1 and the surface of Comparative Example 1. Detailed Implementation

[0046] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0047] Unless otherwise specified, the reagents, methods, instruments, and equipment used in this invention are conventional in the art. Unless otherwise specified, the reagents and materials used in the following examples are all commercially available and of analytical grade.

[0048] Example 1:

[0049] A robust superhydrophobic surface for low-temperature steel and its preparation method, such as Figure 1 As shown, it includes the following steps:

[0050] Step (1): Select FH36 marine low-temperature steel and make a 10×10mm square sample by wire cutting. Clean the sample with anhydrous ethanol for 5 minutes. Polish the cleaned sample with 180#, 600#, 1200# and 2000# metallographic sandpaper respectively.

[0051] Step (2): Picosecond laser etching is performed on the surface of the sample prepared in step (1). The path of the picosecond laser etching is designed as staggered concentric circles (e.g., Figure 2 As shown, the outer circle has a diameter of 30 μm, the inner circle has a diameter of 15 μm, and the center-to-center distance between the concentric circles is 50 μm. The outer circle is laser-processed once, followed by the inner circle twice. This process is recorded as one laser processing cycle. The laser etching process parameters are set as follows: laser diameter 10 μm, laser power 2.42 W, laser frequency 2000 kHz, and operating speed 70 mm / s. The picosecond laser processing cycle is 7 times.

[0052] Step (3): The sample obtained in step (2) is subjected to vacuum heat treatment to obtain a robust superhydrophobic marine low-temperature steel surface. The vacuum treatment parameters are 1 bar, the temperature is 100℃, and the treatment time is 6h.

[0053] Example 2:

[0054] A robust superhydrophobic surface for low-temperature steel and its preparation method, comprising the following steps:

[0055] Step (1): Select FH36 marine low-temperature steel and make a 10×10mm square sample by wire cutting. Clean the sample with anhydrous ethanol for 5 minutes. Polish the cleaned sample with 180#, 600#, 1200# and 2000# metallographic sandpaper respectively.

[0056] Step (2): Picosecond laser etching is performed on the surface of the sample prepared in step (1). The path of the picosecond laser etching is designed as staggered concentric circles, with an outer circle diameter of 30 μm, an inner circle diameter of 15 μm, and a center-to-center distance of 50 μm. The outer circle is laser-processed once, followed by the inner circle twice. This process is recorded as one laser processing cycle. The laser etching process parameters are set as follows: laser diameter 10 μm, laser power 2.1 W, laser frequency 1500 kHz, and running speed 50 mm / s. The picosecond laser processing cycle is 4 times.

[0057] Step (3): The sample obtained in step (2) is subjected to vacuum heat treatment to obtain a robust superhydrophobic marine low-temperature steel surface. The vacuum treatment parameters are 1 bar, the temperature is 150℃, and the treatment time is 3h.

[0058] Example 3:

[0059] A robust superhydrophobic surface for low-temperature steel and its preparation method, comprising the following steps:

[0060] Step (1): Select FH36 marine low-temperature steel and make a 10×10mm square sample by wire cutting. Clean the sample with anhydrous ethanol for 5 minutes. Polish the cleaned sample with 180#, 600#, 1200# and 2000# metallographic sandpaper respectively.

[0061] Step (2): Picosecond laser etching is performed on the surface of the sample prepared in step (1). The path of the picosecond laser etching is designed as staggered concentric circles, with an outer circle diameter of 30 μm, an inner circle diameter of 15 μm, and a center-to-center distance of 50 μm. The outer circle is laser-processed once, followed by the inner circle twice. This process is recorded as one laser processing cycle. The laser etching process parameters are set as follows: laser diameter 10 μm, laser power 3 W, laser frequency 1000 kHz, and running speed 50 mm / s. The picosecond laser processing cycle is 1 time.

[0062] Step (3): The sample obtained in step (2) is subjected to vacuum heat treatment to obtain a robust superhydrophobic marine low-temperature steel surface. The vacuum treatment parameters are 1 bar, the temperature is 130℃, and the treatment time is 4h.

[0063] Comparative Example 1:

[0064] Comparative Example 1 is FH36 low-temperature steel that has not undergone laser ablation treatment. Figure 3 Here is its scanning electron microscope image.

[0065] The relevant test conditions involved in the above embodiments are as follows:

[0066] Scanning electron microscope (SEM) images were taken using a JSM7500F field emission scanning electron microscope. Three-dimensional profiles and surface roughness were captured using a KEYENCE VK-X150 laser microscope. The water contact angle was measured using a contact angle meter by placing a 5 μL deionized water droplet on a marine-grade low-temperature steel superhydrophobic surface. The sandpaper abrasion test involved placing a 50g-loaded sample, surface-down, on 800# SiC sandpaper. The sample size was 10 × 10 mm, and the surface pressure was 5.18 kPa. The test sample was moved horizontally 10 cm on the sandpaper, then rotated 90°, and moved another 10 cm. This process was defined as one abrasion cycle. The freezing process of a 10 μL water droplet at -10℃ was captured using an industrial-grade camera.

[0067] Figure 4The images show scanning electron microscope (SEM) images (50 μm and 1 μm) of the robust superhydrophobic surface for marine cryogenic steel prepared in Example 1. As shown, the inverted conical armor structure consists of periodically staggered inverted conical pits and surface nanoparticles. This staggered arrangement of inverted conical armor provides excellent superhydrophobicity and mechanical durability to the marine cryogenic steel surface. The diameter of the inverted conical pits on the marine cryogenic steel surface is close to 50 μm, almost the same as the center distance, indicating a relatively small area at the inverted conical pit framework. High-magnification SEM images show that the surface of the inverted conical pits is covered with a large number of nanoscale particles, and the staggered, interconnected inverted conical micron-sized framework structure protects these nanoscale particles like armor.

[0068] Figure 5 The three-dimensional contour map and 2D dimension scanning results of the marine low-temperature steel surface obtained by the 7-cycle laser etching process described in Example 1 show that the surface of the sample in Example 1 exhibits an alternating inverted conical distribution, with a pit depth of about 27 μm, a pit angle of about 60°, and a surface roughness of about 8.43 μm.

[0069] Water droplet contact angle tests were performed on the robust superhydrophobic surfaces of low-temperature steel prepared in Comparative Example 1 and Example 1, such as... Figure 6 As shown, the contact angle changed from 60° to 164°, indicating that the robust superhydrophobic surface for low-temperature steel prepared by this invention has good hydrophobic properties.

[0070] A sandpaper abrasion test was conducted on the surface of the robust marine low-temperature steel prepared in Example 1. Figure 7 As shown. The robust marine cryogenic steel surface prepared in Example 1 can withstand 38 sandpaper abrasion cycles, that is, after moving 7.6m, it still retains superhydrophobic properties, indicating that the robust superhydrophobic surface for cryogenic steel prepared in this invention has good mechanical durability. Figure 7 The images show SEM images (50 μm and 25 μm) of the robust superhydrophobic surface for low-temperature steel prepared in Example 1 after 10 sandpaper abrasion cycles. In the sandpaper abrasion test, only the frame of the robust superhydrophobic surface for low-temperature steel prepared in Example 1 showed wear marks; the nanoparticles inside the inverted conical structure remained intact. The inverted conical frame acts like armor, resisting wear and protecting the inner nanoparticles. This demonstrates that the robust superhydrophobic surface for low-temperature steel prepared according to this invention possesses excellent mechanical durability.

[0071] A water droplet contact angle test was performed on the robust superhydrophobic surface of the low-temperature steel prepared in Example 2, and the contact angle was approximately 159°. A sandpaper abrasion test was also performed on the surface of the robust marine low-temperature steel prepared in Example 2. Figure 7As shown in the figure, the robust marine cryogenic steel surface prepared in Example 2 can withstand 25 sandpaper abrasion cycles, i.e., after moving 5m, it still retains its superhydrophobic properties, indicating that the robust superhydrophobic surface for cryogenic steel prepared in this invention has good mechanical durability. An icing time test was conducted on the robust superhydrophobic surface for cryogenic steel prepared in Example 2. The icing time of water droplets on the surface of the robust superhydrophobic marine cryogenic steel prepared in Example 2 was 152s, significantly longer than the icing time of the original steel surface. Therefore, the robust superhydrophobic surface for cryogenic steel prepared in Example 2 has good wear resistance and anti-icing properties.

[0072] A water droplet contact angle test was performed on the robust superhydrophobic surface of the low-temperature steel prepared in Example 3, and the contact angle was approximately 155°. A sandpaper abrasion test was also performed on the surface of the robust marine low-temperature steel prepared in Example 3. Figure 8 As shown in the figure, the robust marine cryogenic steel surface prepared in Example 3 can withstand 8 sandpaper abrasion cycles, i.e., after moving 1.6m, and still retains its superhydrophobic properties, indicating that the robust superhydrophobic surface for cryogenic steel prepared in this invention has good mechanical durability. An icing time test was conducted on the robust superhydrophobic surface for cryogenic steel prepared in Example 3. The icing time of water droplets on the robust superhydrophobic marine cryogenic steel surface prepared in Example 3 was 98s, significantly longer than the icing time of the original steel surface. Therefore, the robust superhydrophobic surface for cryogenic steel prepared in Example 3 also has good wear resistance and anti-icing properties.

[0073] Figure 9 This image shows a comparison of the water droplet freezing process between the robust superhydrophobic surface for low-temperature steel prepared in Example 1 and the surface of Comparative Example 1. Water droplets on the FH36 steel surface rapidly freeze into ice droplets within 10 seconds. The freezing time of water droplets on the robust superhydrophobic marine low-temperature steel surface prepared in Example 1 is significantly longer, increasing to 192 seconds. This is due to the superhydrophobic properties of the coating in Example 1. Based on the Cassie-Baxter model, a water-air-solid interface can be formed on its surface, reducing the contact area between the water droplet and the coating in Example 1, effectively preventing the nucleation and growth of water droplets, and delaying their freezing time. Furthermore, a high contact angle indicates a larger free energy barrier that water droplet nucleation and growth must overcome, making freezing more difficult. Therefore, the robust superhydrophobic surface for low-temperature steel prepared in Example 1 exhibits good anti-icing performance at low temperatures.

[0074] In summary, this invention utilizes picosecond laser processing technology to ultimately construct a robust superhydrophobic surface with an armor structure on the surface of low-temperature steel. The staggered inverted conical armor structure provides excellent superhydrophobicity and mechanical durability for marine low-temperature steel surfaces, which can meet the requirements of ice resistance and mechanical durability of low-temperature steel in polar ship applications.

[0075] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A method for preparing a robust superhydrophobic surface for low-temperature steel, characterized in that, Includes the following steps: S1: Pretreatment of the surface of low-temperature steel; S2: The pretreated low-temperature steel surface undergoes laser ablation treatment; The laser ablation process is performed by uniformly arranged concentric circles, with an outer circle diameter of 25-35 μm, an inner circle diameter of 10-20 μm, and a center-to-center distance of 45-55 μm. The outer and inner circles are alternately subjected to laser ablation treatment. One laser processing of the outer circle and two processing of the inner circle are counted as one cycle. The cycle of alternating treatment is 1-7 times. The laser ablation process uses an ultraviolet picosecond laser with a laser spot diameter of 10-15 μm, a laser power of 2-3 W, a laser frequency of 1000-2000 kHz, and a running speed of 50-100 mm / s. S3: Vacuum heat treatment is performed on the low-temperature steel surface after ablation treatment. The heat treatment temperature is 100-150℃ and the heat treatment time is 3-6h. The superhydrophobic surface has an arranged inverted conical armor structure, providing superhydrophobicity and mechanical durability to the marine low-temperature steel surface; the inverted conical armor structure includes inverted conical pits and nanoparticles on the surface of the pits, and the inverted conical pits are periodically staggered.

2. The method for preparing a robust superhydrophobic surface for low-temperature steel according to claim 1, characterized in that, In step S1, the pretreatment includes cleaning and polishing; The cleaning process uses anhydrous ethanol. The polishing process uses metallographic sandpaper.

3. The method for preparing a robust superhydrophobic surface for low-temperature steel according to claim 2, characterized in that, The cleaning is performed under ultrasonic conditions for 5-10 minutes. The polishing process employs gradient polishing.

4. A robust superhydrophobic surface for low-temperature steel, characterized in that, It is obtained by the preparation method described in any one of claims 1-3.

5. The application of the robust superhydrophobic surface for low-temperature steel as described in claim 4 in polar vessels.

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