Marine cryogenic steel and method for regulating surface wettability thereof

Abstract

The application relates to a low-temperature steel surface treatment method, in particular to a marine low-temperature steel and a surface wettability regulation method thereof, which comprises the following steps: forming a micro-nano structure array on the surface of the pretreated marine low-temperature steel through at least one laser ablation treatment, and completing the regulation of the surface wettability of the marine low-temperature steel through a post-treatment process; the surface of the marine low-temperature steel has the micro-nano structure array, and forms a super-hydrophobic surface. Compared with the prior art, the application solves the problem that in the prior art, the regulation of the surface wettability of the metal needs to change the laser ablation process parameters, so that the regulation complexity is extremely high; the micro-nano structure of the surface is accurately regulated through different times of laser ablation treatment without changing the laser ablation process parameters, so that the marine low-temperature steel surface shows the adhesive behavior of rose state or lotus leaf state.

Description

Technical Field

[0001] This invention relates to a method for surface treatment of low-temperature steel, specifically to a method for controlling the surface wettability of marine low-temperature steel. Background Technology

[0002] Superhydrophobic surfaces, defined as surfaces with a water contact angle greater than 150°, have attracted widespread attention due to their excellent water repellency in areas such as self-cleaning, antibacterial, corrosion resistance, anti-icing, and droplet transport. To meet these diverse practical applications, superhydrophobic surfaces also require varying degrees of adhesion. For example, in applications involving non-destructive droplet transport and selective droplet transport, superhydrophobic surfaces should exhibit high adhesion to droplets; while in applications requiring self-cleaning, anti-icing, and anti-microbial adhesion, superhydrophobic surfaces must possess extremely low adhesion. Just as water droplets on lotus and rose petals in nature exhibit near-perfect spherical shapes, lotus leaf surfaces have low adhesion, allowing for high droplet flow, while rose surfaces have high adhesion, preventing droplets from sliding off regardless of the angle of inclination. Therefore, the manipulation of superhydrophobic surfaces between the rose and lotus leaf states has become a current research focus.

[0003] Current methods primarily involve adjusting surface morphology or chemical composition to alter the surface roughness or surface energy of superhydrophobic surfaces, thereby changing their water adhesion. Much research currently focuses on preparing superhydrophobic surfaces with tunable adhesion using organic materials, but these methods suffer from limitations in application or poor adhesion between organic materials and substrates. Therefore, directly preparing superhydrophobic metal surfaces with tunable adhesion on metal surfaces will become a future trend.

[0004] In recent years, laser ablation technology has attracted increasing attention due to its advantages such as high processing speed, simple and safe operation, precise control of surface structure, and high repeatability. Laser ablation directly constructs micro- and nano-structures on material surfaces and is widely applicable to materials including glass, graphene, ceramics, and metals such as aluminum, copper, and stainless steel. However, there is currently no research on using laser ablation to prepare superhydrophobic surfaces for marine cryogenic steel. Furthermore, laser ablation of intrinsically hydrophobic non-metallic materials readily yields superhydrophobic surfaces, while metallic surfaces, mostly hydrophilic, often exhibit superhydrophilicity after laser ablation, requiring modification with low surface energy chemicals. For example, CN202210487053.5 requires coating deposition after laser ablation, and CN201410657627.4 requires surface modification with low surface energy materials after crystalline laser ablation. However, chemical modification techniques suffer from increased manufacturing costs, operational complexity, poor durability, and limited application scenarios. Therefore, the preparation of superhydrophobic metallic surfaces without chemical modification has become a research hotspot. This includes the question of how to adjust the wettability of superhydrophobic surfaces using laser ablation. Laser ablation can control the adhesion of superhydrophobic surfaces by adjusting laser process parameters, including output power, scanning speed, and scanning spacing. Currently, this technology is mainly used in the field of non-metallic materials, such as polydimethylsiloxane and polytetrafluoroethylene. Controlling the adhesion of superhydrophobic surfaces by adjusting one or even multiple laser process parameters is a very complex and cumbersome process. Furthermore, the laser process parameters do not work independently; adjusting any one parameter will affect the actual output of other parameters, thus affecting the overall laser ablation effect, making it impossible to accurately control and predict the surface morphology of the material.

[0005] Chinese patent CN202110564332.2 discloses a method for rapidly preparing a biomimetic superhydrophobic surface of titanium alloy using a femtosecond laser. The steps are as follows: S1, pre-treating the titanium alloy surface; S2, laser etching is performed on the titanium alloy surface using a femtosecond laser to form a dual-scale micro / nano structure, namely, forming an ordered, periodic micron-scale papillary structure on the titanium alloy surface, with densely distributed nano-scale rod-shaped particles on the papillary structure; after laser etching, the ablation on the titanium alloy surface is removed by cleaning. The molten particles or impurities are removed. Specific laser etching parameters are: laser pulse width 275 fs, single pulse energy 3.1-3.6 μJ, frequency 50-900 kHz, scanning speed 50-900 mm / s, scanning spacing 10-50 μm, number of scans 10-30, and scanning path in a grid pattern. S3: The laser-etched titanium alloy is placed in a furnace at 130-170℃ for 7.5-8.5 hours. After removal, it is cleaned to remove ablation fragments or contaminants from the titanium alloy surface. This scheme involves laser etching and aging of the titanium alloy to obtain a superhydrophobic surface. However, this scheme only works on titanium alloys and can only obtain lotus leaf-like superhydrophobic surfaces, not rose-like superhydrophobic surfaces. Therefore, the applications of the products prepared are still limited.

[0006] Therefore, in view of the problems and defects in the existing technology, there is a need for a new process to effectively control the wettability of the low-temperature bar surface. Summary of the Invention

[0007] The purpose of this invention is to provide a method for controlling the surface wettability of marine cryogenic steel in order to solve at least one of the above-mentioned problems. This method addresses the issue that controlling the surface wettability of metals in the prior art requires changing the laser ablation process parameters, which results in extremely high complexity. This invention achieves precise control of the micro-nano structure of the surface through different laser ablation treatments without changing the laser ablation process parameters, so that the surface of marine cryogenic steel exhibits rose-like or lotus-leaf-like adhesion behavior.

[0008] The objective of this invention is achieved through the following technical solution:

[0009] The first aspect of this invention discloses a method for controlling the surface wettability of marine low-temperature steel, comprising the following steps:

[0010] A micro-nano structure array is formed by performing at least one laser ablation treatment on the pretreated marine low-temperature steel surface, and the wettability of the marine low-temperature steel surface is controlled by a post-processing process.

[0011] Preferably, the pretreatment includes cleaning and sanding, wherein the cleaning uses anhydrous ethanol and the sanding uses metallographic sandpaper.

[0012] More preferably, the cleaning is ultrasonic cleaning, in which the marine low-temperature steel is ultrasonically cleaned in anhydrous ethanol for 5 minutes; the sanding is performed sequentially using 180#, 600#, 1200#, and 2000# metallographic sandpaper.

[0013] Preferably, the marine low-temperature steel is DH36, EH40, or FH36.

[0014] Preferably, the laser ablation process is performed along vertical grid lines with a spacing of 30-70 μm.

[0015] Preferably, the laser ablation treatment uses an ultraviolet picosecond laser with a laser diameter of 10 μm, a laser power of 2.1-4 W, a laser frequency of 500-2000 kHz, and an operating speed of 100-300 mm / s.

[0016] Preferably, the laser ablation process is performed 1-20 times.

[0017] Among them, when the number of laser ablation treatments is 1-2 times, the resulting marine low-temperature steel has a conventional hydrophobic surface; when the number of laser ablation treatments is 3-7 times, the resulting marine low-temperature steel has a rose-shaped (state) superhydrophobic surface; when the number of laser ablation treatments is 8-20 times, the resulting marine low-temperature steel has a lotus leaf-shaped (state) superhydrophobic surface.

[0018] Preferably, the post-processing is vacuum treatment or natural aging treatment.

[0019] Preferably, the vacuum degree of the vacuum treatment is 8×10⁻⁶. -5 -2×10 -4 Pa, processing time is 6-10 hours.

[0020] Preferably, the natural aging treatment is carried out at a temperature of 20-25°C for 5-15 days.

[0021] The second aspect of the present invention discloses a marine cryogenic steel treated by any of the control methods described above, wherein the surface of the marine cryogenic steel has a micro-nano structure array to form a superhydrophobic surface.

[0022] Preferably, the micro-nano structure is composed of periodically matrix-distributed nanoparticles and micron-sized prisms, which provides roughness to the surface of marine low-temperature steel.

[0023] The working principle of this invention is as follows:

[0024] Changes in surface morphology and roughness affect the wettability of the sample. After 1-2 laser treatments, the surface roughness is very small, the contact area between the water droplet and the sample surface is large, and nanoscale grooves occupy the entire prism surface, exhibiting a normal hydrophobic state. At this time, the adhesion force on the sample surface is extremely high. After 3-7 laser treatments, the surface roughness of the sample increases slightly, the nanoparticles on the prism surface begin to increase in size and agglomerate slightly, some grooves are covered, and the contact area between the sample surface and the water droplet decreases. Under the combined action of van der Waals forces and the negative pressure generated by the sealed air, the surface has strong adhesion and exhibits a rose-like state. As the number of laser treatments continues to increase, the prism height and prism spacing continue to increase, and the particles on the prism surface also gradually increase in size. The increase in sample surface roughness and the disappearance of nanogrooves result in a large Laplace pressure on the surface, thus forming a lotus leaf-like state.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) This invention uses laser ablation process to prepare a superhydrophobic surface with adjustable adhesion on a low-temperature steel surface for the first time. No toxic or harmful chemical reagents or chemical processes are used in the process, making the process simple and environmentally friendly.

[0027] (2) Without changing the laser ablation process parameters, the present invention precisely controls the micro-nano structure of the surface by laser ablation treatment of different times, thereby achieving precise control of the wettability of the marine low-temperature steel surface, so that the marine low-temperature steel surface not only exhibits superhydrophobicity, but also exhibits rose-like or lotus-leaf-like adhesion behavior.

[0028] (3) Based on the analysis of the surface morphology and wettability of different grades of marine low-temperature steel after laser ablation treatment, the process method for controlling the surface wettability of marine low-temperature steel provided by the present invention is generally applicable to marine low-temperature steel and has wide applicability.

[0029] (4) The process method of the present invention for controlling the wettability of marine low-temperature steel surface can produce marine low-temperature steel surfaces with different wettability that can be used in fields such as droplet non-destructive transportation, thus broadening the application range of marine low-temperature steel. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the process flow for the control method;

[0031] Figure 2 The images are scanning electron microscope (SEM) images (25 μm, 2 μm) of marine cryogenic steel surfaces with different wettability obtained in Example 1, where (a), (b) and (c) correspond to marine cryogenic steel surfaces obtained by 1, 5 and 15 laser etching processes, respectively.

[0032] Figure 3This is a three-dimensional contour image of the surface of marine low-temperature steel obtained by 15 laser etching processes in Example 1.

[0033] Figure 4 The results of water droplet contact angle tests on marine low-temperature steel surfaces with different wettability obtained in Example 1 are shown. (a), (b) and (c) correspond to marine low-temperature steel surfaces obtained by 1, 5 and 15 laser etching processes, respectively.

[0034] Figure 5 The results of water adhesion behavior tests on marine low-temperature steel surfaces with different wettability prepared in Example 1;

[0035] Figure 6 The image shows a test of non-destructive water droplet transport of marine cryogenic steels with different wettability prepared in Example 1. Detailed Implementation

[0036] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0037] The test conditions involved in the following examples are as follows: 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 10 μL droplet of deionized water onto a marine-grade low-temperature steel superhydrophobic surface. Water droplet adhesion behavior and the non-destructive transport process were captured using an industrial-grade camera.

[0038] like Figure 1 As shown, a process for controlling the surface wettability of marine low-temperature steel includes the following steps:

[0039] (1) Clean the marine low-temperature steel and polish it with sandpaper;

[0040] (2) The surface of the marine low-temperature steel obtained in step (1) is subjected to laser ablation treatment by ultraviolet picosecond laser equipment for different numbers of times to obtain a micro-nano structure array composed of nanoparticles and micron prisms.

[0041] (3) The samples obtained in step (2) are subjected to high vacuum treatment or natural aging treatment to obtain marine low temperature steel surfaces with different wettability.

[0042] Example 1

[0043] Step (1): Select EH40 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.

[0044] Step (2): The sample surface prepared in step (1) was subjected to picosecond laser etching of different numbers of times. The path of the picosecond laser etching was designed as vertical grid lines with a spacing of 40 μm. The laser etching process parameters were set as follows: laser diameter 10 μm, laser power 2.26 W, laser frequency 2000 kHz, and running speed 200 mm / s. The number of picosecond laser etchings were 1, 5, and 15 times, respectively.

[0045] Step (3): The sample obtained in step (2) is subjected to high vacuum treatment to obtain marine low-temperature steel surfaces with different wettability. The high vacuum treatment parameters are a vacuum degree of 8×10⁻⁶. -5 Pa, vacuum treatment time 6h.

[0046] Figure 2 The images show scanning electron microscope (SEM) images (25 μm and 2 μm) of marine cryogenic steel surfaces with different wettability obtained in Example 1. As shown in (a), (b) and (c), the marine cryogenic steel surface has a periodic matrix distribution of micro-nano structures composed of nanoparticles and prisms, which provides roughness to the marine cryogenic steel surface. Figure 2 (a) shows the surface morphology of EH40 marine low-temperature steel after one laser treatment. It is observed that the surface is relatively flat, with nanoscale grooves occupying the entire prism surface, randomly covered by a small number of extremely small nanoparticles. For example... Figure 2 As shown in (b), after five laser treatments, the nanoparticles on the prism surface began to increase in size and agglomerate slightly, and some of the grooves were covered. Figure 2 As shown in (c), when the number of laser irradiations is 15, the nanoparticles on the prism surface continue to increase in size and aggregate toward the center.

[0047] Figure 3 The image shows a three-dimensional contour of the marine low-temperature steel surface obtained by the 15 laser etching processes described in Example 1. It can be seen that the surface of the sample in Example 1 exhibits a uniform and regular prismatic distribution.

[0048] Water droplet contact angle tests were performed on the surfaces of marine low-temperature steels with different wettability prepared in Example 1, such as... Figure 4 As shown in the figure, (a), (b), and (c) are the marine low-temperature steel surfaces obtained by laser etching processes of 1, 5, and 15 times, respectively, with contact angles of approximately 142°, 153°, and 158°, respectively. This indicates that the process method of the present invention for controlling the wettability of marine low-temperature steel surfaces has a good control effect on the wettability of marine low-temperature steel surfaces.

[0049] Water adhesion behavior tests were conducted on the surfaces of marine low-temperature steels with different wettability prepared in Example 1, such as... Figure 5 As shown, when a 10 μL water droplet is pressed onto the surface of marine cryogenic steel prepared by 1 and 5 laser etching processes, the water droplet adheres to the surface of the sample. The sample prepared by 1 laser etching process has a larger contact area with the water droplet and stronger surface adhesion compared to the sample prepared by 5 laser etching processes. When a 10 μL water droplet is pressed onto the surface of marine cryogenic steel prepared by 15 laser etching processes, it does not adhere. This indicates that the process method of the present invention for controlling the surface wettability of marine cryogenic steel has a good control effect on the surface wettability of marine cryogenic steel.

[0050] Figure 6 Water droplet non-destructive transport tests were conducted on marine cryogenic steel surfaces with different wettability prepared in Example 1. The marine cryogenic steel surface prepared by five laser etching processes was effectively used as a transport tool, transferring water droplets from the marine cryogenic steel surface prepared by 15 laser etching processes to the marine cryogenic steel surface prepared by one laser etching process without any loss. This demonstrates that the process method of the present invention for controlling the wettability of marine cryogenic steel surfaces has a good controllable effect on the wettability of marine cryogenic steel surfaces.

[0051] Example 2

[0052] 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.

[0053] Step (2): The sample surface prepared in step (1) was subjected to picosecond laser etching for different numbers of times. The path of the picosecond laser etching was designed as vertical grid lines with a spacing of 50 μm. The laser etching process parameters were set as follows: laser diameter 10 μm, laser power 2.35 W, laser frequency 1800 kHz, and running speed 180 mm / s. The number of picosecond laser etchings were 1, 4, and 10 times, respectively.

[0054] Step (3): The sample obtained in step (2) is subjected to natural aging treatment to obtain marine low temperature steel surfaces with different wettability. The natural aging treatment environment temperature is 20℃ and the placement time is 15 days.

[0055] Water droplet contact angle tests were conducted on marine cryogenic steel surfaces with different wettability prepared in Example 2. The contact angles were approximately 138°, 152°, and 157°, respectively. Water adhesion behavior tests were also conducted on the marine cryogenic steel surfaces with different wettability prepared in Example 2. When a 10 μL water droplet was pressed onto the marine cryogenic steel surfaces prepared with 1 and 4 laser etching processes, the water droplet adhered to the surface of the sample. The sample with 1 laser etching process had a larger contact area with the water droplet and stronger surface adhesion compared to the sample with 4 laser etching processes. A 10 μL water droplet pressed onto the marine cryogenic steel surface prepared with 10 laser etching processes did not adhere. Water droplet non-destructive transport tests were conducted on the marine cryogenic steel surfaces with different wettability prepared in Example 2. The marine cryogenic steel surface prepared with 4 laser etching processes was effectively used as a transport tool, transferring water droplets from the marine cryogenic steel surface prepared with 10 laser etching processes to the marine cryogenic steel surface prepared with 1 laser etching process without any loss. Therefore, it is demonstrated that the process method of the present invention for controlling the surface wettability of marine low-temperature steel has a good control effect on the surface wettability of marine low-temperature steel.

[0056] Example 3

[0057] Step (1): Select DH36 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 in sequence.

[0058] Step (2): The sample surface prepared in step (1) was subjected to picosecond laser etching for different numbers of times. The path of the picosecond laser etching was designed as vertical grid lines with a spacing of 70 μm. The laser etching process parameters were set as follows: laser diameter 10 μm, laser power 4 W, laser frequency 500 kHz, and running speed 300 mm / s. The number of picosecond laser etchings were 1, 3, and 8 times, respectively.

[0059] Step (3): The sample obtained in step (2) is subjected to natural aging treatment to obtain marine low temperature steel surfaces with different wettability. The natural aging treatment environment temperature is 25℃ and the placement time is 5 days.

[0060] Water droplet contact angle tests were conducted on marine cryogenic steel surfaces with different wettability prepared in Example 3. The contact angles were approximately 142°, 153°, and 156°, respectively. Water adhesion behavior tests were also conducted on the marine cryogenic steel surfaces with different wettability prepared in Example 3. When a 10 μL water droplet was pressed onto the marine cryogenic steel surfaces prepared with 1 and 3 laser etching processes, the water droplet adhered to the surface of the sample. The sample with 1 laser etching process had a larger contact area with the water droplet and stronger surface adhesion compared to the sample with 3 laser etching processes. A 10 μL water droplet pressed onto the marine cryogenic steel surface prepared with 8 laser etching processes did not adhere. Water droplet non-destructive transport tests were conducted on the marine cryogenic steel surfaces with different wettability prepared in Example 3. The marine cryogenic steel surface prepared with 3 laser etching processes was effectively used as a transport tool, transferring water droplets from the marine cryogenic steel surface prepared with 8 laser etching processes to the marine cryogenic steel surface prepared with 1 laser etching process without any loss. Therefore, it is demonstrated that the process method of the present invention for controlling the surface wettability of marine low-temperature steel has a good control effect on the surface wettability of marine low-temperature steel.

[0061] Example 4

[0062] Step (1): Select DH36 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 in sequence.

[0063] Step (2): The sample surface prepared in step (1) was subjected to picosecond laser etching for different numbers of times. The path of the picosecond laser etching was designed as vertical grid lines with a spacing of 30 μm. The laser etching process parameters were set as follows: laser diameter 10 μm, laser power 2.1 W, laser frequency 2000 kHz, and running speed 100 mm / s. The number of picosecond laser etchings were 2, 7, and 20 times, respectively.

[0064] Step (3): The sample obtained in step (2) is subjected to high vacuum treatment to obtain marine low-temperature steel surfaces with different wettability. The high vacuum treatment parameters are a vacuum degree of 2×10⁻⁶. -4 Pa, vacuum treatment time 10h.

[0065] Water droplet contact angle tests were conducted on marine cryogenic steel surfaces with different wettability prepared in Example 4, and the contact angles were approximately 144°, 153°, and 157°, respectively. Water adhesion behavior tests were also conducted on the marine cryogenic steel surfaces with different wettability prepared in Example 4. When a 10 μL water droplet was pressed onto the marine cryogenic steel surfaces prepared with 2 and 7 laser etching processes, the water droplet adhered to the surface of the sample. The sample prepared with 2 laser etching processes had a larger contact area with the water droplet and stronger surface adhesion compared to the sample prepared with 7 laser etching processes. A 10 μL water droplet pressed onto the marine cryogenic steel surface prepared with 20 laser etching processes did not adhere. Water droplet non-destructive transport tests were conducted on the marine cryogenic steel surfaces with different wettability prepared in Example 4. The marine cryogenic steel surface prepared with 7 laser etching processes was effectively used as a transport tool, transferring water droplets from the marine cryogenic steel surface prepared with 20 laser etching processes to the marine cryogenic steel surface prepared with 2 laser etching processes without any loss. Therefore, it is demonstrated that the process method of the present invention for controlling the surface wettability of marine low-temperature steel has a good control effect on the surface wettability of marine low-temperature steel.

[0066] In summary, this invention provides a process for controlling the wettability of marine cryogenic steel surfaces. This invention, for the first time, prepares a superhydrophobic surface with tunable adhesion on cryogenic steel surfaces using laser ablation, without using any toxic or harmful chemical reagents or processes. Without changing the laser ablation process parameters, the micro-nano structure of the marine cryogenic steel surface is adjusted by different numbers of laser ablation treatments, exhibiting different rose-like and lotus-leaf-like adhesion behaviors. Analysis of the surface morphology and wettability of different grades of marine cryogenic steel after laser treatment shows that the process for controlling the wettability of marine cryogenic steel surfaces provided by this invention is generally applicable to marine cryogenic steel. It demonstrates that superhydrophobic metal surfaces treated with different numbers of laser ablation treatments can be used in fields such as droplet non-destructive transport. Due to its excellent multifunctionality and simple, environmentally friendly preparation method, it has excellent practical application prospects.

[0067] 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 controlling the surface wettability of marine low-temperature steel, characterized in that, Includes the following steps: A micro-nano structure array is formed by performing at least one laser ablation treatment on the pretreated marine low-temperature steel surface, and the wettability of the marine low-temperature steel surface is controlled through a post-processing process. The laser ablation process uses an ultraviolet picosecond laser with a diameter of 10 μm, a laser power of 2.1-4 W, a laser frequency of 500-2000 kHz, and a running speed of 100-300 mm / s. The laser ablation path consists of vertical grid lines with a grid spacing of 30-70 μm. The laser ablation treatment is performed 1-20 times. When the laser ablation treatment is performed 1-2 times, the resulting marine low-temperature steel has a conventional hydrophobic surface. When the laser ablation treatment is performed 3-7 times, the resulting marine low-temperature steel has a rose-shaped superhydrophobic surface. When the laser ablation treatment is performed 8-20 times, the resulting marine low-temperature steel has a lotus leaf-shaped superhydrophobic surface.

2. The method for controlling the surface wettability of marine low-temperature steel according to claim 1, characterized in that, The pretreatment includes cleaning and sanding. The cleaning uses anhydrous ethanol, and the sanding uses metallographic sandpaper.

3. The method for controlling the surface wettability of marine low-temperature steel according to claim 1, characterized in that, The post-processing process is either vacuum treatment or natural aging treatment.

4. The method for controlling the surface wettability of marine low-temperature steel according to claim 3, characterized in that, The vacuum degree of the vacuum treatment is 8×10⁻⁶. -5 -2×10 -4 Pa, processing time is 6-10 hours.

5. The method for controlling the surface wettability of marine low-temperature steel according to claim 3, characterized in that, The natural aging process is carried out at a temperature of 20-25℃ for 5-15 days.

6. A marine low-temperature steel treated using the control method described in any one of claims 1-5, characterized in that, The surface of the marine low-temperature steel has a micro-nano structure array, forming a superhydrophobic surface.

7. The marine low-temperature steel surface according to claim 6, characterized in that, The micro-nano structure is composed of periodically matrix-distributed nanoparticles and micron-sized prisms.

Images