An aluminum alloy low-ice-adhesion deicing surface and a method of making the same

Abstract

This invention relates to the field of metal surface functionalization and de-icing technology, and particularly to a low-ice-adhesion de-icing surface for aluminum alloys and its preparation method. The surface comprises an aluminum alloy substrate, a continuous strip-shaped micro / nanostructure layer disposed on the surface of the aluminum alloy substrate, and a low surface energy modification layer covering the surface of the continuous strip-shaped micro / nanostructure layer. The continuous strip-shaped micro / nanostructure layer consists of a micron-scale main structure and nano-scale redeposited particles forming a layered rough surface. The low-ice-adhesion de-icing surface of this invention maintains superhydrophobic properties at room temperature, exhibits low ice adhesion at low temperatures, and demonstrates good cyclic de-icing stability. The formed continuous strip-shaped micro / nanostructure layer helps to enhance local thermal mismatch stress concentration during the continued cooling process after freezing, promotes the initiation and propagation of fine cracks in the ice layer, and reduces subsequent desorption resistance. This provides a new technical route for the design and preparation of low-ice-adhesion de-icing surfaces for aluminum alloys and has good application prospects.

Description

Technical Field

[0001] This invention relates to the field of metal surface functionalization and anti-icing technology, and in particular to an aluminum alloy low-ice adhesion anti-icing surface and its preparation method. Background Technology

[0002] Aluminum alloys are widely used in aerospace, transportation, and energy equipment due to their light weight, high strength, and good corrosion resistance. However, aluminum alloys are prone to icing in low-temperature and high-humidity environments, leading to enhanced interfacial adhesion, increased operating resistance, and decreased service performance, which can seriously affect equipment operational safety. Existing methods such as thermal de-icing, mechanical de-icing, and chemical de-icing typically suffer from high energy consumption, complex processes, high maintenance costs, or heavy environmental burdens. Therefore, developing low-energy-consumption, long-life, and highly stable passive anti-icing surfaces is of great significance.

[0003] Currently, passive anti-icing and de-icing surfaces based on superhydrophobic principles are widely recognized as one of the most promising solutions. By constructing micro- and nano-structures on metal surfaces and combining them with low surface energy modifications, it is possible to achieve the bouncing removal of water droplets before freezing (anti-icing) or reduce the adhesion force after freezing (de-icing). For example, Chinese invention patent CN111846193A discloses a superhydrophobic anti-icing aerospace aluminum alloy surface. This surface, through a combination of ultrafast laser ablation and wet chemical methods, constructs a multi-level structure on the aluminum alloy surface based on three-dimensional micron cones, with nanosheets and nanofloral clusters distributed on the surface. After modification with low surface energy materials, it achieves an ultra-low ice adhesion strength of approximately 6 kPa, demonstrating the enormous potential of micro- and nano-structures in reducing ice adhesion.

[0004] However, despite the extremely low initial ice adhesion force of the micro / nanostructure surface prepared in CN111846193A, the performance stability of this surface still needs improvement under actual repeated icing-de-icing cycle service conditions. This is mainly because the regular and periodically distributed single-size micrometer cone array is relatively monolithic in topology. During the sustained low-temperature stage after icing, the ability of such single-scale regular structures under ice cover to regulate interfacial thermal mismatch stress is limited, which easily leads to strong overall ice layer integrity and performance degradation after repeated icing-de-icing cycles.

[0005] Furthermore, from the perspective of preparation methods, most existing laser-based methods for preparing anti-icing surfaces focus on constructing single-period, single-morphology micro / nano structures through regular scanning paths. Although CN111846193A employs a strategy combining ultrafast lasers with wet chemistry, its laser processing steps are primarily used to form basic regular micron-cone arrays, while subsequent complex nanostructures still rely on chemical growth. While this approach can form multi-level structures, the control of micron-scale morphology mainly remains at the level of uniform arrays, lacking a laser processing strategy to achieve complex, non-uniform (such as gradient or stripe-like) two-dimensional patterns through candidate pattern generation, screening, and scanning path conversion. In particular, there is a lack of a method for preparing anti-icing surfaces of aluminum alloys that can balance pattern machinability, surface mechanical stability, and long-term low ice adhesion performance.

[0006] Therefore, in view of the problems that existing micro-nano structures such as regular microcones, micro-pillars, and grooves have limited topological forms, limited ability to control interfacial thermal mismatch stress during the continuous cooling stage after freezing, strong integrity of ice layers, and easy performance degradation after repeated freezing-de-icing cycles, it is necessary to provide a method for preparing aluminum alloy low-ice adhesion anti-de-icing surfaces based on reaction diffusion pattern screening and ultrafast laser scanning conversion. This is a technical problem that urgently needs to be solved by those skilled in the art.

[0007] In view of this, the present invention is proposed. Summary of the Invention

[0008] The primary objective of this invention is to provide an aluminum alloy surface with low ice adhesion and anti-icing properties. This surface maintains superhydrophobicity at room temperature, exhibits low ice adhesion at low temperatures, and demonstrates good stability during cyclic de-icing.

[0009] The second objective of this invention is to provide a method for preparing a low-ice-adhesion, anti-icing surface for aluminum alloys. This invention generates and screens target two-dimensional patterns through a reaction-diffusion model, and then converts them into an ultrafast laser scanning path, thereby achieving the controllable preparation of complex strip-shaped micro-nano structures on the surface of aluminum alloys and establishing a complete technical route of "pattern generation - pattern screening - scanning path conversion - laser processing - low surface energy modification".

[0010] In a first aspect, the present invention provides an aluminum alloy low-ice-adhesion anti-icing surface, comprising an aluminum alloy substrate, a continuous strip-shaped micro-nano structure layer disposed on the surface of the aluminum alloy substrate, and a low surface energy modification layer covering the surface of the continuous strip-shaped micro-nano structure layer. The continuous strip-shaped micro / nano structure layer consists of a micron-scale main structure and nano-scale redeposited particles, forming a layered rough surface.

[0011] Secondly, this invention also discloses a method for preparing an aluminum alloy low-ice-adhesion anti-icing surface, comprising the following steps: Multiple candidate two-dimensional patterns are generated based on the reaction-diffusion model, and the target pattern is selected from the candidate two-dimensional patterns. The target pattern is converted into an ultrafast laser scanning path, so that the processing area in the target pattern corresponds to the laser scanning area. The ultrafast laser is used to scan and process the surface of the aluminum alloy substrate according to the scanning path to form a continuous strip-shaped microstructure. By modifying the surface after ultrafast laser processing with low surface energy, an aluminum alloy surface with low ice adhesion and anti-icing properties is obtained.

[0012] This invention generates and filters target two-dimensional patterns using a reaction-diffusion model, then converts them into ultrafast laser scanning paths. This enables the controllable fabrication of complex strip-shaped micro / nano structures on aluminum alloy surfaces, establishing a complete technical route of "pattern generation—pattern filtering—scanning path conversion—laser processing—low surface energy modification." This method balances pattern machinability, surface coverage, and low ice adhesion performance, constructing continuous strip-shaped hierarchical micro / nano structures on aluminum alloy surfaces. This results in anti-icing surfaces with low ice adhesion and good cyclic anti-icing stability, overcoming the shortcomings of existing regular single-scale micro / nano structures in terms of cyclic anti-icing stability. It meets the practical needs of high-end equipment such as aerospace for long-life, high-reliability anti-icing surfaces, providing a new technical route for the design and fabrication of low-ice-adhesion anti-icing surfaces on aluminum alloys, and has promising application prospects.

[0013] As a preferred embodiment of this technical solution, the reaction-diffusion model is the Gray-Scott reaction-diffusion model.

[0014] As a preferred embodiment of this technical solution, the candidate two-dimensional pattern is a strip-shaped two-dimensional pattern that can cover the surface of the aluminum alloy substrate.

[0015] More preferably, the steps for generating multiple sets of candidate two-dimensional patterns based on the reaction-diffusion model are as follows: (1) Establish a two-dimensional computational domain and set the initial concentration distribution of the two components within the domain; (2) Set the diffusion parameters, supply parameters and consumption parameters in the Gray-Scott reaction-diffusion model so that the two components diffuse, react and dissipate in a two-dimensional plane; (3) Through numerical iterative calculation, the system evolves over time and gradually forms a stable two-dimensional spatial distribution pattern; (4) When the pattern evolves to a stable state, extract the concentration distribution result of one component and perform binarization according to the set threshold to obtain a black and white two-dimensional pattern. (5) In the obtained black and white two-dimensional pattern, the black area is defined as the area to be processed by laser, and the white area is defined as the unprocessed support area; (6) By adjusting the parameters of the Gray-Scott model, repeat the above process to generate multiple sets of candidate two-dimensional patterns.

[0016] In this invention, the specific parameters involved in the Gray-Scott reaction-diffusion model are not strictly limited, but are based on the fact that the Gray-Scott reaction-diffusion model can generate target patterns with specific conditions.

[0017] More preferably, from the generated candidate two-dimensional patterns, target patterns suitable for whole-surface processing, with high surface coverage, theoretical line spacing matching the laser spot diameter, and theoretical solid-liquid contact ratio meeting the requirements are selected for subsequent ultrafast laser scanning processing.

[0018] The target pattern selected by this invention simultaneously meets the requirements of theoretical line spacing, theoretical solid-liquid contact ratio, and surface coverage, which is beneficial for forming a continuous hierarchical rough structure with high coverage on the surface after processing, thereby taking into account both machinability and anti-icing performance.

[0019] As a preferred embodiment of this technical solution, the target pattern has a high surface coverage rate, excluding patterns with large blank areas, and at least simultaneously meets the following conditions: the theoretical line spacing is 1-2 times the diameter of the ultrafast laser spot used, and the theoretical solid-liquid contact ratio is 15%-20%. Here, the theoretical line spacing refers to the distance between the center lines of adjacent strip-shaped microstructures; the theoretical solid-liquid contact ratio refers to the ratio of the actual contact area of ​​the solid to the apparent projected area, and its calculation formula is: f = S 未加工 / S 总 ×100%, where S 未加工 S represents the area of ​​the white, unprocessed support region in the two-dimensional pattern. 总 The total area of ​​the apparent projection region corresponding to the target pattern; the spot diameter is the actual spot diameter of the ultrafast laser beam focused on the processing surface, which can be obtained through conventional optical measurement methods.

[0020] Studies have shown that when the theoretical line spacing is smaller than the spot diameter, adjacent strips will overlap excessively, resulting in the inability to form a clear strip-shaped microstructure. When the theoretical line spacing is greater than twice the spot diameter, the surface coverage is insufficient, which is not conducive to achieving low-ice adhesion performance. When the theoretical solid-liquid contact ratio is less than 15%, the proportion of unprocessed support area is too low, which is not conducive to forming a stable and continuous strip-shaped microstructure. When the theoretical solid-liquid contact ratio is greater than 20%, the proportion of processed area is insufficient, the effective surface roughness structure coverage decreases, which is not conducive to achieving low-ice adhesion.

[0021] More preferably, the target pattern satisfies at least the following conditions: the theoretical line spacing is 1-2 times the diameter of the ultrafast laser spot used, and the theoretical solid-liquid contact ratio is 16%-18%.

[0022] As a preferred embodiment of this technical solution, the processing depth of the ultrafast laser is 0.4-1.0 times the diameter of the ultrafast laser spot.

[0023] More preferably, the processing depth of the ultrafast laser is 0.5-0.8 times the diameter of the ultrafast laser spot.

[0024] More preferably, the selected target pattern is a two-dimensional black and white image, where the black areas correspond to the processed areas and the white areas correspond to the unprocessed areas. The specific steps for converting the target pattern into an ultrafast laser scanning path and using an ultrafast laser to scan and process the aluminum alloy substrate surface according to the scanning path to form a continuous strip-shaped microstructure are as follows: (1) Import the selected two-dimensional black and white pattern into the path processing software; (2) Extract the boundary information of the black processing area to obtain the laser processing path; (3) Based on the principle that the single processing bandwidth is consistent with the laser spot diameter, the processing path is simulated to obtain the theoretical solid-liquid contact ratio; (4) Convert the laser processing path into a scanning trajectory file that can be recognized by the ultrafast laser processing equipment; (5) Set the size of the laser processing path to adjust the scanning line spacing so that the laser completes the scanning processing line by line on the aluminum alloy surface along the path; (6) After scanning, a continuous strip-shaped microstructure corresponding to the target pattern is formed on the surface of the aluminum alloy.

[0025] For example, the laser spot diameter is 45μm, the theoretical line spacing of the target pattern is 45-90μm, and the processing depth is about 30μm.

[0026] When the laser processes along the scanning path, the bandwidth of a single processing line is determined by the diameter of the laser spot. Therefore, under different laser spot conditions, it is only necessary to adjust the spacing between the path lines and the processing depth accordingly to still obtain similar strip-shaped micro-nano structures and similar technical effects.

[0027] As a preferred embodiment of this technical solution, the ultrafast laser is a femtosecond laser.

[0028] More preferably, the present invention does not strictly limit the process parameters of femtosecond laser processing, but aims to achieve a layered rough surface composed of a continuous strip-shaped micron main structure and nano-scale redeposited particles that can be stably formed on the surface of an aluminum alloy substrate.

[0029] More preferably, the femtosecond laser processing parameters are: laser wavelength 1030nm, average power 2W, pulse width 268fs, repetition frequency 100kHz, scanning speed 50mm / s, and number of scans 3.

[0030] As a preferred embodiment of this technical solution, the low surface energy modification is performed using fluorinated silane modification.

[0031] More preferably, the fluorinated silane includes, but is not limited to, 1H,1H,2H,2H-perfluorodecyltrimethoxysilane.

[0032] This invention does not strictly limit the specific method of fluorinated silane modification, but aims to avoid damaging the continuous strip-shaped microstructure obtained by ultrafast laser processing.

[0033] More preferably, the step of modifying the surface after ultrafast laser processing with low surface energy according to the present invention is as follows: The aluminum alloy substrate, after being processed by ultrafast laser, is cleaned with anhydrous ethanol and dried with high-purity nitrogen. Then, the sample and 1H,1H,2H,2H-perfluorodecyltrimethoxysilane (PFOTS) are placed in the same sealed container, wherein the sample and PFOTS do not come into direct contact. Preferably, the aluminum alloy substrate is placed on the top of the sealed container or on a sample holder, and the PFOTS is placed on the bottom of the sealed container or in a separate small dish. The sample is modified by vapor deposition to form a low surface energy modification layer on the sample surface.

[0034] More preferably, during the vapor deposition process, the processing temperature is 80-100℃ and the time is 1.5-2.5h, so that the perfluorodecyltrimethoxysilane vaporizes and undergoes chemical vapor deposition on the surface of the aluminum alloy substrate to form a low surface energy modification layer; after the modification is completed, the sample is taken out and naturally cooled to room temperature to obtain an aluminum alloy low ice adhesion anti-icing surface.

[0035] More preferably, the amount of perfluorodecyltrimethoxysilane used is sufficient to form a stable vapor environment within a sealed container and achieve uniform vapor phase modification of the aluminum alloy substrate surface. In this embodiment, a sealed container with a volume of approximately 1L is used, and the amount of perfluorodecyltrimethoxysilane is 0.5g. For aluminum alloy substrates with different surface areas, the amount of perfluorodecyltrimethoxysilane or the volume of the sealed container can be adjusted accordingly; this invention does not impose strict limitations on these adjustments.

[0036] As a preferred embodiment of this technical solution, the aluminum alloy substrate is cleaned, dried, and pretreated before use to remove surface contaminants and provide a stable base surface for subsequent laser processing.

[0037] More preferably, the steps of cleaning, drying, and pretreating the aluminum alloy substrate according to the present invention are as follows: The aluminum alloy substrate was ultrasonically cleaned by sequentially placing it in anhydrous ethanol and acetone solutions to make its surface smooth and remove the oxide layer.

[0038] The present invention does not strictly limit the specific type of aluminum alloy substrate, for example, it includes any one of 2024 aluminum alloy, 5052 aluminum alloy, 7075 aluminum alloy and 6061 aluminum alloy.

[0039] More preferably, the aluminum alloy substrate of the present invention is 6061 aluminum alloy, which is more closely related to the application scenarios of aircraft skin and can be directly applied to aircraft surface anti-icing. However, the technical route of the present invention is not limited to 6061 aluminum alloy. From the perspective of process applicability, similar structures can also be prepared from metal substrates such as copper and titanium that can undergo ultrafast laser surface processing.

[0040] The aluminum alloy low-ice adhesion anti-icing and de-icing surface of the present invention has at least the following beneficial effects: 1. Although the complex strip-like structure formed on the low-ice-adhesion anti-icing and de-icing surface of the aluminum alloy of the present invention is not a regular periodic structure, it can still achieve superhydrophobic properties similar to those of regular micro-nano structures.

[0041] 2. The aluminum alloy low-ice-adhesion anti-icing surface of the present invention does not only rely on low surface energy modification and low solid-liquid contact area to reduce ice adhesion. Its superior performance compared to regular micron-shaped pillars and groove structures further endows it with excellent low-ice-adhesion performance and cyclic de-icing stability.

[0042] 3. The continuous strip-shaped topology structure constructed by the aluminum alloy low-ice adhesion anti-icing and de-icing surface of the present invention is conducive to enhancing the local thermal mismatch stress concentration during the continued cooling process after freezing, thereby making it easier to promote the formation and diffusion of a dense and interconnected crack network in the ice layer, weakening the overall integrity of the ice layer, and thus reducing the subsequent desorption resistance.

[0043] 4. Through observation of ice crack morphology and thermal stress analysis, it can be seen that the structure of the aluminum alloy low ice adhesion anti-icing and de-icing surface of the present invention not only changes the ambient temperature wetting state, but also further regulates the distribution of interfacial thermal mismatch stress after freezing. This effect cannot be directly achieved by regular micron columns or unidirectional groove structures.

[0044] 5. The aluminum alloy low-ice adhesion anti-icing surface of the present invention has a static water contact angle greater than 150° at room temperature, an ice adhesion strength of less than 2 kPa at low temperature, and an ice adhesion strength of less than 8 kPa after 10 freezing-de-icing cycles. The first preferred pattern has an ice adhesion strength of 5.94 kPa after the 10th cycle, and the second preferred pattern has an ice adhesion strength of 6.60 kPa after the 10th cycle. Attached Figure Description

[0045] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0046] Figure 1 This is a flowchart of the preparation method of the aluminum alloy low-ice adhesion anti-icing and de-icing surface of the present invention; Figure 2 This is the first preferred pattern of Embodiment 1 of the present invention (black represents the processed area, and white represents the unprocessed area); Figure 3 This is the second preferred pattern in Embodiment 2 of the present invention (black represents the processed area, and white represents the unprocessed area); Figure 4 The surface morphology after femtosecond laser processing according to the present invention is as follows: (a) a first preferred pattern; (b) a second preferred pattern; Figure 5 For the ice adhesion strength test of the present invention: (a) first preferred pattern (Example 1); (b) second preferred pattern (Example 2); (c) regular micropillar structure (Comparative Example 1); (d) regular groove structure (Comparative Example 2); Figure 6 The ice crack morphology diagrams of the present invention are as follows: (a) first preferred pattern (Example 1); (b) second preferred pattern (Example 2); (c) regular micron column structure (Comparative Example 1); (d) regular groove structure (Comparative Example 2).

[0047] Figure 7 The contact angle and roll-off angle diagrams of the present invention are as follows: (a) first preferred pattern (Example 1); (b) second preferred pattern (Example 2); (c) regular micropillar structure (Comparative Example 1); (d) regular groove structure (Comparative Example 2). Detailed Implementation

[0048] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0049] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations according to this application. As used herein, the singular form includes the plural form unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this description, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0050] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] Example 1 like Figure 1 As shown, this embodiment provides a method for preparing an aluminum alloy low-ice-adhesion anti-icing surface, including the following steps: 6061 aluminum alloy was selected as the substrate material, and the aluminum alloy substrate was ultrasonically cleaned in anhydrous ethanol and acetone solutions in sequence to make its surface smooth and remove the oxide layer. Multiple candidate two-dimensional patterns were generated based on the reaction-diffusion model and screened according to the following criteria: the patterns have high surface coverage. The pattern does not contain large blank areas; The theoretical line spacing of the pattern is 1-2 times the diameter of the ultrafast laser spot used; The theoretical solid-liquid contact ratio of the pattern is controlled within the range of 15%-20%.

[0052] The process of generating multiple candidate two-dimensional patterns based on the reaction-diffusion model is as follows: (1) Establish a two-dimensional computational region and set the initial concentration distribution of two components within the region. For example, the initial concentration of component U is set to a higher value, preferably 1, and the initial concentration of component V is set to a lower value, preferably 0. In the local perturbation region, a non-zero initial value of component V is introduced, and the concentration of component U in the region is reduced accordingly to trigger the reaction diffusion process. (2) Set the diffusion parameters, supply parameters and consumption parameters in the Gray-Scott reaction diffusion model. The main parameters to be adjusted are the supply parameter F and the consumption parameter K. The diffusion parameters can be set to default or fixed settings so that the two components diffuse, react and dissipate in the two-dimensional plane. (3) Through numerical iterative calculation, the system evolves over time and gradually forms a stable two-dimensional spatial distribution pattern; (4) When the pattern evolves to a stable state, extract the concentration distribution result of one component and perform binarization according to the set threshold to obtain a black and white two-dimensional pattern. (5) In the obtained black and white two-dimensional pattern, the black area is defined as the area to be processed by laser, and the white area is defined as the unprocessed support area; (6) By adjusting the parameters of the Gray-Scott model, repeat the above process to generate multiple sets of candidate two-dimensional patterns.

[0053] After screening, the first preferred pattern obtained in this embodiment is as follows: Figure 2 As shown, its theoretical solid-liquid contact ratio is 16.58%.

[0054] The target pattern is converted into a femtosecond laser scanning path and scanned on a 6061 aluminum alloy substrate. The diameter of the femtosecond laser spot is 45μm, corresponding to a theoretical line spacing of 45-90μm, and the processing depth is approximately 30μm.

[0055] The process of converting the target pattern into a femtosecond laser scanning path and performing scanning processing is as follows: (1) Import the selected two-dimensional black and white pattern into the path processing software; (2) Extract the boundary information of the black processing area to obtain the laser processing path; (3) Based on the principle that the single processing bandwidth is consistent with the laser spot diameter, the processing path is simulated and the theoretical solid-liquid contact ratio is 16.58%. (4) Convert the laser processing path into a scanning trajectory file that can be recognized by the femtosecond laser processing equipment; (5) Set the size of the laser processing path to adjust the scanning line spacing so that the laser can complete the scanning processing line by line on the surface of the aluminum alloy substrate along the path; (6) After scanning, a continuous strip-shaped microstructure corresponding to the target pattern is formed on the surface of the aluminum alloy substrate.

[0056] In this embodiment, the femtosecond laser processing parameters are: laser wavelength 1030nm, average power 2W, pulse width 268fs, repetition frequency 100kHz, scanning speed 50mm / s, and number of scans 3.

[0057] like Figure 4 As shown in (a), in this embodiment, after femtosecond laser processing, a layered rough structure is formed on the surface, which is composed of a micron-scale main structure and nano-scale redeposited particles.

[0058] The aluminum alloy substrate, after being processed by femtosecond laser, was cleaned with anhydrous ethanol and dried with high-purity nitrogen. Then, the sample and 1H,1H,2H,2H-perfluorodecyltrimethoxysilane were placed in the same sealed container. The aluminum alloy substrate was placed on the sample holder of the sealed container, and the perfluorodecyltrimethoxysilane was placed in a separate small dish in the sealed container. The sealed container was placed in an oven and heated at 90°C for 2 hours to vaporize the perfluorodecyltrimethoxysilane and cause chemical vapor deposition on the sample surface, forming a low surface energy modification layer, thus obtaining a low-ice-adhesion anti-icing surface of the aluminum alloy.

[0059] Example 2 This embodiment is basically the same as embodiment 1, except that the second preferred pattern is selected as the target pattern.

[0060] The second preferred pattern obtained after screening in this embodiment is as follows: Figure 3 As shown, its theoretical solid-liquid contact ratio is 17.01%.

[0061] like Figure 4 As shown in (b), after femtosecond laser processing, the surface of this embodiment forms a layered rough structure composed of a micron-scale main structure and nano-scale redeposited particles.

[0062] Compare with Example 1 This embodiment is basically the same as Embodiment 1, except that: firstly, a regular micron-shaped column structure is prepared on the surface of the pretreated 6061 aluminum alloy substrate using a femtosecond laser cross-line scanning method. The femtosecond laser processing parameters are preferably consistent with those in Embodiment 1, namely, laser wavelength 1030nm, average power 2W, pulse width 268fs, repetition frequency 100kHz, scanning speed 50mm / s, and scanning times 3. Then, a low surface energy modification layer is formed on the surface of the regular micron-shaped column structure using the vapor deposition method of Embodiment 1.

[0063] Compare with Example 2 This embodiment is basically the same as Embodiment 1, except that: firstly, a regular groove structure is prepared on the surface of the pretreated 6061 aluminum alloy substrate using a femtosecond laser parallel line scanning method. The femtosecond laser processing parameters are preferably consistent with those in Embodiment 1, namely, laser wavelength 1030nm, average power 2W, pulse width 268fs, repetition frequency 100kHz, scanning speed 50mm / s, and scanning times 3. Then, a low surface energy modification layer is formed on the surface of the regular micron column structure using the vapor deposition method of Embodiment 1.

[0064] Figures 5-7 The results are as follows: ice adhesion strength test, ice crack morphology diagram and surface contact angle test results of aluminum alloy low ice adhesion anti-icing surface obtained in Examples 1-2 and Comparative Examples 1-2.

[0065] Depend on Figure 5 It can be seen that, compared with Examples 1-2, the aluminum alloy low-ice adhesion anti-icing surface with regular micron column structure and the aluminum alloy low-ice adhesion anti-icing surface with regular groove structure in Comparative Examples 1-2 also have hydrophobicity at room temperature. Figure 7 However, during the low-temperature freezing-de-icing cycle, its ice adhesion strength is significantly higher than that of the continuous strip structure prepared in Examples 1-2 of this invention, and its cycle stability is poor.

[0066] Depend on Figure 6 It can be seen that the aluminum alloy low-ice adhesion anti-icing surface with continuous strip structure prepared in Examples 1-2 of the present invention is more likely to form a dense and interconnected crack network during the continuous low temperature stage, thus its subsequent de-icing resistance is lower. In contrast, the crack propagation path of Comparative Examples 1-2 is singular, especially Comparative Example 2, which mainly propagates in a single direction, and the ice layer has a strong integrity, which to some extent increases the subsequent desorption resistance.

[0067] In summary, the low-ice-adhesion anti-icing surface of this invention maintains superhydrophobic properties at room temperature, with a static water contact angle greater than 150°. It exhibits low ice adhesion at low temperatures, with a low-temperature ice adhesion strength below 2 kPa, and demonstrates good cyclic de-icing stability. The formed continuous strip-shaped micro / nano structure layer helps enhance local thermal mismatch stress concentration during the continued cooling process after freezing, promotes the initiation and propagation of fine cracks in the ice layer, and reduces subsequent desorption resistance. After 10 freezing-de-icing cycles, the ice adhesion strength remains below 8 kPa; the first preferred pattern reaches 5.94 kPa after the 10th cycle, and the second preferred pattern reaches 6.60 kPa after the 10th cycle. Therefore, this invention provides a novel technical route for the design and preparation of low-ice-adhesion anti-icing surfaces for aluminum alloys, with promising application prospects.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An aluminum alloy low-ice-adhesion anti-icing surface, characterized in that, It includes an aluminum alloy substrate, a continuous strip-shaped micro / nano structure layer disposed on the surface of the aluminum alloy substrate, and a low surface energy modification layer covering the surface of the continuous strip-shaped micro / nano structure layer; The continuous strip-shaped micro / nano structure layer consists of a micron-scale main structure and nano-scale redeposited particles, forming a layered rough surface.

2. A method for preparing an aluminum alloy low-ice-adhesion anti-icing surface, characterized in that, Includes the following steps: Multiple candidate two-dimensional patterns are generated based on the reaction-diffusion model, and the target pattern is selected from the candidate two-dimensional patterns. The target pattern is converted into an ultrafast laser scanning path, and an ultrafast laser is used to scan and process the surface of the aluminum alloy substrate according to the scanning path to form a continuous strip-shaped microstructure. By modifying the surface after ultrafast laser processing with low surface energy, an aluminum alloy surface with low ice adhesion and anti-icing properties is obtained.

3. The method for preparing a low-ice-adhesion, anti-icing surface for aluminum alloys according to claim 2, characterized in that, The candidate two-dimensional pattern is a strip-shaped two-dimensional pattern that can cover the surface of the aluminum alloy substrate.

4. The method for preparing a low-ice-adhesion, anti-icing surface for aluminum alloys according to claim 2, characterized in that, The target pattern must simultaneously meet at least the following conditions: the theoretical line spacing is 1-2 times the diameter of the ultrafast laser spot used, and the theoretical solid-liquid contact ratio is 15%-20%.

5. The method for preparing a low-ice-adhesion, anti-icing surface for aluminum alloys according to claim 2, characterized in that, The processing depth of the ultrafast laser is 0.4-1.0 times the diameter of the ultrafast laser spot.

6. The method for preparing an aluminum alloy low-ice adhesion anti-icing surface according to claim 2, characterized in that, The reaction-diffusion model is the Gray-Scott reaction-diffusion model.

7. The method for preparing a low-ice-adhesion, anti-icing surface for aluminum alloys according to claim 2, characterized in that, The ultrafast laser is a femtosecond laser.

8. The method for preparing a low-ice-adhesion, anti-icing surface for aluminum alloys according to claim 2, characterized in that, The low surface energy modification is performed using fluorinated silanes.

9. The method for preparing an aluminum alloy low-ice adhesion anti-icing and de-icing surface according to claim 2, characterized in that, The aluminum alloy substrate is cleaned, dried, and pretreated before use.

10. The method for preparing an aluminum alloy low-ice adhesion anti-icing surface according to claim 2, characterized in that, The aluminum alloy substrate includes any one of 2024 aluminum alloy, 5052 aluminum alloy, 7075 aluminum alloy, and 6061 aluminum alloy.

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