Laser-chemical combined processing method for micro-nano structure of metal surface and metal part

Abstract

The application relates to the field of ultrafast laser micro-nano processing technology, in particular to a metal surface patterning micro-nano processing method and a metal piece. The processing method comprises the following steps: irradiating the surface of the metal piece by using an ultrafast laser according to a predetermined path, so as to form a first micro-nano structure on the surface of the metal piece; chemically treating the surface of the metal piece with the first micro-nano structure by using a chemical reagent, so that the first micro-nano structure changes and a second micro-nano structure is formed on the surface of the metal piece; and cleaning the surface of the metal piece after the chemical treatment, so that the metal piece with the micro-nano structure on the surface is obtained. On the basis of preparing the first micro-nano structure on the surface of the metal piece by using the ultrafast laser micro-nano processing, the appearance and contour of the first micro-nano structure on the surface of the metal piece are secondarily regulated by combining with the wet chemical treatment, the processing process is simple and efficient, is free and flexible, the micro-nano structure with the controllable appearance and contour can be obtained on the surface of the metal piece, and the purpose of fine patterning processing is achieved.

Description

Technical Field

[0001] This application belongs to the field of ultrafast laser micro-nano processing technology, specifically relating to a method for patterning metal surfaces and metal parts. Background Technology

[0002] Ultrafast laser micro / nano fabrication technology utilizes the nonlinear interaction between ultrashort laser pulses and materials to fabricate complex micro / nano structures and devices with high precision (down to the nanometer scale). It boasts advantages such as non-contact operation, high controllability, flexible processing, and applicability to various materials, and is widely used in semiconductor manufacturing, micro / nano electromechanical systems (MEMS / NEMS) fabrication, optical component fabrication, flexible electronic devices and sensors, and functional surface preparation. However, in many cases, ultrafast laser micro / nano fabrication alone is insufficient to obtain the desired surface micro / nano patterns or structures, or faces challenges such as insufficient processing efficiency. Combining ultrafast laser fabrication with dry etching and wet chemical processing is an effective strategy to enhance the controllability of surface micro / nano patterns / structures and improve fabrication efficiency. However, both dry etching and wet chemical processing are primarily used on dielectric materials such as glass and silicon, or non-metallic materials. Research on metallic materials is limited, and how to control the morphology and contour of micro / nano patterns / structures on metallic materials remains an unsolved problem. Summary of the Invention

[0003] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, this invention proposes a processing method and a metal part for forming patterned micro / nano structures with controllable morphological contours on the surface of a metal part.

[0004] A first aspect of this application provides a method for patterning micro / nano-scale fabrication of metal surfaces. According to embodiments of this application, the method includes: irradiating the surface of a metal part with an ultrafast laser along a predetermined path to form a first micro / nano-structure on the surface of the metal part; chemically treating the surface of the metal part with the first micro / nano-structure formed thereon with a chemical reagent to change the first micro / nano-structure and form a second micro / nano-structure on the surface of the metal part; and cleaning the surface of the chemically treated metal part to obtain a metal part with a micro / nano-structure on its surface. This method, based on the preparation of a first micro / nano-structure on the surface of a metal part using ultrafast laser micro / nano-scale fabrication, combines wet chemical treatment to further control the morphology and contour of the first micro / nano-structure on the surface of the metal part. The processing is simple, efficient, and flexible, and can obtain micro / nano-structures with controllable morphology and contour on the surface of metal parts.

[0005] According to embodiments of this application, the metal component includes at least one of gold, silver, platinum, aluminum and aluminum alloys, magnesium and magnesium alloys, zinc and zinc alloys, copper and copper alloys, titanium and titanium alloys, tungsten and tungsten alloys, nickel and nickel alloys, manganese and manganese alloys, iron, and steel.

[0006] According to embodiments of this application, the form of the metal component includes at least one of a metal block, a metal foil, a metal mesh, and a metal foam.

[0007] According to embodiments of this application, the ultrafast laser satisfies at least one of the following conditions:

[0008] The ultrafast laser is at least one of ultraviolet, infrared, and visible light;

[0009] The wavelength of the ultrafast laser is 100nm to 2000nm;

[0010] The pulse width of the ultrafast laser is 1 fs to 30 ps;

[0011] The pulse frequency of the ultrafast laser is 1 Hz to 1 GHz;

[0012] The average power of the ultrafast laser is 1mW to 10kW.

[0013] According to embodiments of this application, the predetermined path includes at least one of points, parallel lines, intersecting lines, loops, concentric circles, spirals, meanders, and free patterns.

[0014] According to an embodiment of this application, the first micro / nano structure includes a microstructure and a first nanostructure located on the first microstructure.

[0015] In some embodiments, the first micron structure includes at least one of a first micron protrusion, a first micron pit, and combinations thereof.

[0016] According to embodiments of this application, the shape of the first micrometer protrusion includes at least one of conical, frustum-shaped, cylindrical, truncated square, and irregularly shaped protrusions.

[0017] According to an embodiment of this application, the lateral dimension of the first micrometer protrusion is 0.1 μm to 1000 μm.

[0018] According to embodiments of this application, the shape of the first micron-sized pit includes at least one of the following: circular, elliptical, square, polygonal, groove-shaped, and irregularly shaped hole.

[0019] According to an embodiment of this application, the lateral dimension of the first micron-sized pit is 0.1 μm to 1000 μm.

[0020] According to embodiments of this application, the nanostructure includes at least one of nanoparticles, nanoripples, nanofibers, nanosynapses, and nanoparticle clusters.

[0021] According to embodiments of this application, the chemical reagents include at least one of acids, bases, salts, and their mixed solutions, specifically such as water, hydrochloric acid, nitric acid, sulfuric acid, hydrofluoric acid, potassium hydroxide, sodium hydroxide, sodium aluminate, and their mixed solutions; the above chemical reagents can be used alone or mixed according to a certain concentration ratio before use.

[0022] According to an embodiment of this application, the temperature of the chemical treatment is -100℃ to 300℃;

[0023] According to embodiments of this application, the chemical treatment time can be from 1 second to 120 hours.

[0024] According to embodiments of this application, the change in the first micro / nano structure includes at least one of the following:

[0025] 1) The first nanostructure is removed, and the surface of the first microstructure becomes smoother;

[0026] 2) The microcracks or microgaps at the edge of the first micron-sized pit contour are removed, making the edge of the first micron-sized pit contour clearer;

[0027] 3) The first micrometer-sized protrusion gradually disappears;

[0028] 4) The outline of the first micrometer pit gradually expands and the depth of the first micrometer pit gradually increases;

[0029] 5) The shape of the first micrometer-sized pit changes;

[0030] 6) Precipitates appear on the surface of the first micron protrusion or the first micron pit.

[0031] According to embodiments of this application, the second micro / nano structure includes at least one of a second micrometer protrusion, a second micrometer pit, and combinations thereof.

[0032] According to embodiments of this application, the shape of the second micrometer protrusion includes at least one of conical, frustum-shaped, cylindrical, truncated square, and irregularly shaped protrusions.

[0033] According to an embodiment of this application, the lateral dimension of the second micrometer protrusion is 0.1 μm to 1000 μm.

[0034] According to embodiments of this application, the shape of the second micron-sized pit includes at least one of the following: circular, elliptical, square, polygonal, groove-shaped, and irregularly shaped hole.

[0035] According to an embodiment of this application, the lateral dimension of the second micron-sized pit is 0.1 μm to 1000 μm.

[0036] In a second aspect, this application provides a metal part. According to an embodiment of this application, at least a portion of the surface of the metal part has a micro / nano structure, which is prepared by the aforementioned metal surface patterning micro / nano fabrication method.

[0037] This application has at least the following advantages:

[0038] 1. In this application, wet chemical treatment can simultaneously etch the surface micro-nano structure and achieve patterned control of the structural contour, breaking the limitation that wet chemical treatment can only remove specific areas on the material surface.

[0039] 2. This application enables the etching and morphological contour control of micro-nano structures on metal surfaces, breaking the limitations of the combined laser micro-nano processing and chemical etching method on application materials.

[0040] 3. This application can achieve two-stage patterning and fine control of the micro-nano structure morphology of metal surfaces. By adjusting factors such as the processing path and process parameters of the ultrafast laser, the surface micro-nano structure morphology can be patterned and controlled in one stage. At the same time, by controlling factors such as the concentration and volume of chemical reagents used in the wet chemical treatment process, as well as the temperature and time of the chemical treatment, the surface micro-nano structure morphology can be patterned and controlled in two stages.

[0041] 4. In this application, the treatment of metal surfaces by ultrafast lasers can improve the reaction rate in the subsequent chemical treatment process and guide the site and direction of the chemical reaction. The parallel processing characteristics of chemical treatment improve the processing efficiency of the entire composite processing process. The entire processing process does not require special environmental or procedural requirements. The combination of the advantages of ultrafast laser precision processing and parallel chemical processing is an easy-to-operate, low-cost and efficient method for patterning micro-nano fabrication of controllable morphology and contour of metal surfaces. Attached Figure Description

[0042] Figure 1(a) is a schematic diagram of the femtosecond laser processing path in Example 1.

[0043] Figure 1(b) and Figure 1(c) are scanning electron microscope images of the micro-nano structures obtained on the surface of the aluminum alloy after femtosecond laser irradiation in Example 1 at different magnifications.

[0044] Figures 2(a) and 2(b) show the scanning electron microscope (SEM) images of the micro / nano structures obtained after femtosecond laser processing (i.e., the sample shown in Figure 1) in Example 1, chemically treated at 50°C and held at that temperature for 10 min, at different magnifications. Figures 2(c), 2(d), and 2(e) are the scanning electron microscope (SEM) images of the micro / nano structures obtained after femtosecond laser processing (i.e., the sample shown in Figure 1) in Example 1, chemically treated at 50°C and held at that temperature for 30 min, 50 min, and 70 min, respectively.

[0045] Figures 3(a), 3(b), 3(c), and 3(d) are scanning electron microscope images of the surface patterned micro / nano structures obtained after the samples processed by femtosecond laser in Example 1 were chemically treated at 50°C for 10 min, 30 min, 50 min, and 70 min, respectively, and then ultrasonically cleaned with anhydrous ethanol for 10 min.

[0046] Figure 4 The curve shows the change in the roundness of the micron-sized pits on the surface of the sample processed by femtosecond laser in Example 1 after chemical treatment at 50°C, as a function of the holding time.

[0047] Figure 5(a) is a schematic diagram of the femtosecond laser processing path in Example 2. Figures 5(b) and 5(c) are scanning electron microscope (SEM) images of the micro-nano structures obtained on the aluminum alloy surface after femtosecond laser irradiation in Example 2 at different magnifications. Figures 5(d) and 5(e) are SEM images of the patterned micro-nano structures obtained after the sample shown in Figure 5(b) was chemically treated at 50°C, kept at that temperature for 60 min, and then ultrasonically cleaned with anhydrous ethanol for 10 min.

[0048] Figure 6(a) is a schematic diagram of the femtosecond laser processing path in Example 3. Figure 6(b) is a scanning electron microscope (SEM) image of the micro-nano structure obtained on the surface of the aluminum alloy after femtosecond laser irradiation in Example 3. Figures 6(c), 6(d) and 6(e) are SEM images of the micro-nano structure on the surface of the aluminum alloy after femtosecond laser irradiation in Example 3 after chemical treatment at 50°C for 10 min, 20 min and 30 min respectively, and after ultrasonic cleaning with anhydrous ethanol for 10 min.

[0049] Figure 7(a) is a schematic diagram of the femtosecond laser processing path in Example 4. Figure 7(b) is a scanning electron microscope (SEM) image of the micro-nano structure obtained on the surface of the aluminum alloy after femtosecond laser irradiation in Example 4. Figures 7(c), 7(d) and 7(e) are SEM images of the micro-nano structure on the surface of the aluminum alloy after femtosecond laser irradiation in Example 4 after chemical treatment at 50°C for 30 min, 50 min and 70 min respectively, and after ultrasonic cleaning with anhydrous ethanol for 10 min.

[0050] Figure 8(a) is a scanning electron microscope (SEM) image of the micro / nano structure obtained on the surface of the aluminum alloy after femtosecond laser irradiation in Example 5; Figures 8(b), 8(c) and 8(d) are SEM images of the micro / nano structure on the surface of the aluminum alloy after femtosecond laser irradiation in Example 5 after chemical treatment at 50°C for 30 min, 50 min and 70 min respectively, and after ultrasonic cleaning with anhydrous ethanol for 10 min.

[0051] Figure 9(a) is a schematic diagram of the femtosecond laser processing path in Example 6; Figure 9(b) is a scanning electron microscope (SEM) image of the micro / nano structures obtained on the aluminum alloy surface after femtosecond laser irradiation in Example 6; Figure 9(c) is a SEM image of the micro / nano structures on the surface of the aluminum alloy after femtosecond laser irradiation in Example 6, after two consecutive chemical treatments at 50°C and ultrasonic cleaning with anhydrous ethanol for 10 min. The figures show the microstructures at different locations on the surface of the same sample from left to right.

[0052] Figure 10(a) is a schematic diagram of the femtosecond laser processing path in Example 7; Figure 10(b) is a scanning electron microscope (SEM) image of the micro / nano structures obtained on the aluminum alloy surface after femtosecond laser irradiation in Example 7; Figure 10(c) is a scanning electron microscope (SEM) image of the micro / nano structures on the surface of the aluminum alloy after femtosecond laser irradiation in Example 7, after two consecutive chemical treatments at 50°C and ultrasonic cleaning with anhydrous ethanol for 10 min. The figures show the microstructures at different locations on the surface of the same sample from left to right. Detailed Implementation

[0053] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0054] A first aspect of this application provides a method for patterning micro / nano-scale fabrication of metal surfaces. According to embodiments of this application, the method includes the following steps:

[0055] S10: Irradiate the surface of the metal part using an ultrafast laser along a predetermined path to form a first micro / nano structure on the surface of the metal part.

[0056] According to embodiments of this application, the specific material of the metal component is not particularly limited and can be a metal or alloy, such as at least one of gold, silver, platinum, aluminum and aluminum alloys, magnesium and magnesium alloys, zinc and zinc alloys, copper and copper alloys, titanium and titanium alloys, tungsten and tungsten alloys, nickel and nickel alloys, manganese and manganese alloys, iron, and steel. The specific grade of the aforementioned metal or alloy is not limited. In some specific embodiments, the metal component can be an aluminum alloy component. As an example, the aluminum alloy component includes at least one of 1XXX series, 2XXX series, 3XXX series, 4XXX series, 5XXX series, 6XXX series, 7XXX series, and 8XXX series aluminum alloys, with no specific grade limitation. Therefore, this processing method has a wide range of applications, enabling micro / nano structure processing on various metal surfaces, and is suitable for various uses and application scenarios.

[0057] According to embodiments of this application, the form of the metal component is not particularly limited, and it can be at least one of a metal block, metal foil, metal mesh, or metal foam; the shape of the metal component is also not particularly limited, and it can be any regular or irregular shape. In some embodiments, the metal component includes at least one of a metal block and a metal foil. Therefore, it can be applied to various usage requirements of metal components. It is understood that the metal component can also be various structural components, having the necessary structure and shape for the corresponding structural component, which will not be elaborated further here.

[0058] According to embodiments of this application, the size and thickness of the metal part are not limited. In some embodiments, the thickness of the metal part is 0.01–100 mm. Therefore, it has a wide range of applications and can meet the usage requirements of different scenarios.

[0059] It is understandable that metal parts can be pretreated before ultrafast laser irradiation to remove surface contaminants. Specifically, the surface of the metal parts can be polished or ultrasonically cleaned in a solvent (such as anhydrous ethanol or acetone), then removed and air-dried at room temperature or dried with a dry gas to remove surface contaminants. As an example, the metal parts can be ultrasonically cleaned in anhydrous ethanol or acetone for 1–120 minutes; the gas used to dry the surface of the metal parts can be compressed air, nitrogen, or argon, with a pressure of 1–200 bar and a blowing time of 1–300 seconds.

[0060] In some embodiments, the ultrafast laser irradiation can be performed using an ultrafast laser processing system. Specifically, the metal part can be placed on the processing platform of the ultrafast laser processing system, and the ultrafast laser can be irradiated onto the surface of the metal part and scanned according to a pre-set processing path to obtain a patterned first micro-nano structure on the surface of the metal part.

[0061] In some embodiments, the ultrafast laser processing system may include an ultrafast laser, an external optical path system, a motion system, an observation system, a gas protection system, a dust removal system, etc. The ultrafast laser scanning processing on the surface of the metal part can be achieved by scanning galvanometers (which may be two-dimensional scanning galvanometers, three-dimensional scanning galvanometers, dynamic focusing galvanometers, etc.), polygonal rotating mirrors, multi-beam interference units, spatial light modulators, diffractive optical units, or CNC displacement stages (which may be XY two-axis displacement stages, XYZ three-axis displacement stages, multi-axis displacement stages, etc.) or industrial robots. More complex paths and more refined structures can also be achieved by cooperating scanning galvanometers, polygonal rotating mirrors, multi-beam interference units, spatial light modulators, diffractive optical units, and displacement stages or robots. The relative motion speed between the laser and the metal surface in the scanning processing can be 0.01 to 100,000 mm / s, the scanning interval can be 1 to 1,000 μm, and the number of repeated processing times can be 1 to 1,000.

[0062] Ultrafast lasers, as we understand it, refer to lasers with pulse widths ranging from picoseconds (ps) to femtoseconds (fs). These laser pulses are extremely short, enabling precise processing and measurement of matter with extremely high temporal resolution.

[0063] According to embodiments of this application, the ultrafast laser is at least one of ultraviolet, infrared, and visible light.

[0064] According to embodiments of this application, the wavelength of the ultrafast laser is 100nm to 2000nm, specifically such as 193nm, 206nm, 213nm, 248nm, 258nm, 266nm, 308nm, 337nm, 343nm, 345nm, 355nm, 390nm, 400nm, 445nm, 488nm, 514nm, 515nm, 517nm, 532nm, 633nm, 655nm, 658nm, 780nm, 800nm, 810nm, 900nm, 920nm, 940nm, 980nm, 1030nm, 1035nm, 1064nm, 1315nm, 1470nm, 1500nm, 1550nm, 2000nm, etc.

[0065] According to embodiments of this application, the pulse width of the ultrafast laser is 1fs to 30ps, specifically such as 1fs, 10fs, 50fs, 100fs, 150fs, 190fs, 200fs, 220fs, 240fs, 250fs, 260fs, 280fs, 300fs, 350fs, 400fs, 500fs, 800fs, 1ps, 2ps, 3ps, 4ps, 5ps, 6ps, 7ps, 8ps, 9ps, 10ps, 11ps, 12ps, 15ps, 20ps, 25ps, 30ps, etc.

[0066] According to embodiments of this application, the pulse frequency of the ultrafast laser is 1Hz to 1GHz, specifically such as 1Hz, 10Hz, 100Hz, 1kHz, 10kHz, 20kHz, 25kHz, 30kHz, 40kHz, 50kHz, 100kHz, 110kHz, 150kHz, 200kHz, 220kHz, 250kHz, 300kHz, 330kHz, 350kHz, 400kHz, 450kHz, 500kHz, 550kHz, 600kHz, 650kHz, 700kHz. 750kHz, 800kHz, 850kHz, 900kHz, 950kHz, 1MHz, 2MHz, 3MHz, 4MHz, 5MHz, 6MHz, 7MHz, 8MHz, 9MHz, 10MHz, 20MHz, 30MHz, 40M Hz, 50MHz, 60MHz, 70MHz, 80MHz, 90MHz, 100MHz, 200MHz, 300MHz, 400MHz, 500MHz, 600MHz, 700MHz, 800MHz, 900MHz, 1GHz, etc.

[0067] According to embodiments of this application, the average power of the ultrafast laser is 1mW to 10kW, specifically such as 1mW, 10mW, 100mW, 500mW, 1W, 2W, 3W, 4W, 5W, 6W, 7W, 8W, 9W, 10W, 20W, 30W, 40W, 50W, 60W, 70W, 80W, 90W, 100W, 200W, 500W, 1kW, etc.

[0068] Ultrafast lasers meet the above conditions and can quickly and effectively form the first micro-nano structure on the surface of metal parts. Furthermore, by adjusting the parameters of the ultrafast laser, first micro-nano structures with different shapes, sizes, and distributions can be obtained. Micro-nano structures with controllable morphology can be obtained according to different application scenarios and needs, thus meeting different usage requirements.

[0069] It is understood that in this step, an ultrafast laser is used to scan the surface of the metal part along a predetermined path, thereby forming a first micro / nano structure on the metal part surface. Specifically, the high-energy laser can ablate the metal part, thereby forming the first micro / nano structure on the surface of the metal part. By selecting different scanning paths, a rich variety of patterned first micro / nano structures can be formed on the surface of the metal part.

[0070] According to embodiments of this application, the predetermined path includes at least one of a point, parallel line, intersecting line, ring, concentric circle, spiral, loop, and free pattern. As an example, if the predetermined path is a point, a pit can be formed at the ultrafast laser irradiation location; if the predetermined path is a parallel line, multiple pits distributed along the parallel line or grooves along the parallel line can be formed by adjusting the parameters of the ultrafast laser. In summary, the metal part at the location irradiated by the ultrafast laser is ablated, forming a depression, and corresponding protrusions are formed between adjacent depressions. By irradiating the metal part along different paths with the ultrafast laser, a first micro / nano structure with diverse patterns can be formed.

[0071] Furthermore, the parameters of the ultrafast laser also have a significant impact on the formed first micro / nano structure. For example, different pulse widths, pulse frequencies, and scanning speeds during ultrafast laser irradiation can lead to different patterns in the first micro / nano structure, even when irradiated along the same path. For instance, at a constant pulse frequency, a faster scanning speed may result in multiple spaced pits along the irradiation path, while a slower scanning speed may result in continuous grooves. Based on similar principles, other ultrafast laser parameters also affect the pattern shape of the first micro / nano structure. Therefore, by adjusting the relevant parameters of the ultrafast laser, a rich variety of patterned first micro / nano structures can be obtained.

[0072] In this article, micro- and nanostructures refer to structures at the microscale (micrometer level) and nanoscale, which typically have at least one dimension at the micrometer or nanometer level.

[0073] According to an embodiment of this application, the first micro / nano structure includes a first micrometer structure and a first nanostructure located on the first micrometer structure.

[0074] In some embodiments, the first micron structure includes at least one of a first micron protrusion, a first micron pit, and combinations thereof.

[0075] According to embodiments of this application, the shape of the first micrometer protrusion includes at least one of conical, frustum-shaped, cylindrical, truncated square, and irregularly shaped protrusions.

[0076] According to embodiments of this application, the lateral dimension of the first micrometer protrusion is 0.1μm to 1000μm, specifically such as 0.1μm, 0.2μm, 0.5μm, 1μm, 5μm, 10μm, 20μm, 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, 150μm, 200μm, 250μm, 300μm, 350μm, 400μm, 450μm, 500μm, 750μm, 1000μm, etc. It should be noted that the lateral dimension of the first micrometer protrusion refers to the width of the micrometer protrusion in the horizontal direction.

[0077] According to embodiments of this application, the shape of the first micron-sized pit includes at least one of the following: circular, elliptical, square, polygonal, groove-shaped, and irregularly shaped hole.

[0078] According to embodiments of this application, the lateral dimension of the first micrometer-sized pit is 0.1 μm to 1000 μm, specifically such as 0.1 μm, 0.2 μm, 0.5 μm, 1 μm, 5 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm, 750 μm, 1000 μm, etc. It should be noted that the lateral dimension of the first micrometer-sized pit refers to the width of the pit in the horizontal direction.

[0079] According to embodiments of this application, the arrangement of the first micrometer-sized pits and first micrometer-sized protrusions is not particularly limited and can be adjusted according to the predetermined path of the ultrafast laser, for example, it can be arranged in a regular or random manner. As an example, multiple first micrometer-sized pits and / or multiple first micrometer-sized protrusions can be arranged at intervals along a certain direction, and the size of the multiple first micrometer-sized pits and / or multiple first micrometer-sized protrusions, the spacing between adjacent first micrometer-sized pits or adjacent first micrometer-sized protrusions, etc., can all be flexibly adjusted by adjusting the parameters of the ultrafast laser.

[0080] According to embodiments of this application, the first nanostructure includes at least one of nanoparticles, nanoripples, nanofibers, nanosynapses, and nanoparticle clusters. Specifically, the aforementioned first nanostructure is generated under ultrafast laser irradiation, which induces an extreme non-equilibrium state on the surface of a metal part, leading to complex physical processes such as melting, evaporation, ablation, Coulomb explosion, and phase explosion on the surface of the metal part, thereby generating a nanostructure on the surface of the metal part. The first nanostructure can be nanoparticles, nanoripples, nanofibers, nanosynapses, or nanoparticle clusters, etc.

[0081] It is understood that in this step, first micron structures and first nanostructures of different shapes, sizes, and arrangements can be formed on the surface of the metal part. For example, multiple first micron pits arranged in a matrix, multiple first micron pits arranged along concentric rings, annular grooves arranged in a matrix, multiple first micron protrusions arranged in a matrix, etc., can be formed. Furthermore, the spacing and size between the aforementioned multiple first micron pits, first micron protrusions, and grooves can gradually change along a certain direction (e.g., gradually increasing or gradually decreasing). Even further, the aforementioned first micron structure can possess at least one first nanostructure selected from nanoparticles, nanoripples, nanofibers, nanosynapses, and nanoparticle clusters.

[0082] S20: The surface of the metal part on which the first micro-nano structure is formed is chemically treated with chemical reagents to change the first micro-nano structure and form a second micro-nano structure on the surface of the metal part.

[0083] In this step, chemical reagents can further etch the metal part. Through chemical treatment, the first micro-nano structure can be further shaped and optimized, and the processing speed can be accelerated. That is, the first micro-nano structure changes further during the chemical treatment, thereby quickly obtaining a second micro-nano structure with the target contour and morphology on the surface of the metal part.

[0084] Specifically, the metal part can be immersed in a chemical reagent for chemical treatment, or the chemical reagent can be dripped onto the surface of the metal part for chemical treatment. The specific choice can be made flexibly according to the actual situation, and there are no special restrictions in this application.

[0085] In some embodiments, the chemical treatment can be performed in one step or multiple steps. This can be achieved by immersing the metal part in a chemical reagent for a certain period; or by dripping a certain volume of chemical reagent onto the surface of the metal part and holding it there for a certain period; or by immersing the metal part in a chemical reagent for a certain period, then removing it, and then immersing it in a new chemical reagent for a certain period, repeating this process multiple times as needed; or by dripping a certain volume of chemical reagent onto the surface of the metal part, holding it there for a certain period, removing the chemical reagent from the surface, and then dripping in a new chemical reagent. Of course, multiple chemical reagent replacements can be performed as needed to complete the chemical treatment. Specifically, replacing the chemical reagent can accelerate the reaction rate. Choosing between one-step or multiple-step chemical treatments based on the actual situation allows for a balance between controllable micro / nano structure contours and processing speed.

[0086] According to embodiments of this application, the change in the first micro / nano structure includes at least one of the following:

[0087] 1) The first nanostructure is removed, and the surface of the first microstructure becomes smoother;

[0088] 2) The microcracks or microgaps at the edge of the first micron-sized pit contour are removed, making the contour edge clearer;

[0089] 3) The first micrometer-sized protrusion gradually disappears;

[0090] 4) The outline of the first micrometer pit gradually expands and the depth of the first micrometer pit gradually increases;

[0091] 5) The shape of the first micrometer-sized pit changes;

[0092] 6) Precipitates appear on the surface of the first micron protrusion or the first micron pit.

[0093] Specifically, the chemical processing involves a reaction between chemical reagents and the surface of the metal part, or in other words, a process of chemical reagents corroding the metal part. Both the first nanostructure and the first microstructure in the first micro / nano structure can be corroded, causing the first nanostructure to gradually disappear. As the first microstructure is corroded, its surface gradually becomes smoother. With further corrosion, microcracks or gaps at the edges of the first micro-pit contour can also be removed, making the edges of the first micro-pit contour clearer. Furthermore, the size and depth of the first micro-pit can gradually increase. When the first micro / nano structure includes first micro-protrusions, the size of the first micro-protrusions decreases or disappears with corrosion. For example, the change in the shape of the first micro-pit can manifest as a gradual transition from an irregular elliptical pit to a perfectly circular pit, ultimately exhibiting a polygonal contour.

[0094] It should be noted that as the chemical treatment progresses, the composition of the chemical reagents changes along with the corrosion reaction, and some components of the chemical reagents precipitate out, forming precipitates. Specifically, depending on the different shapes and structures of the first micro / nano structure and the composition of the precipitates, the precipitates may exhibit different structures and shapes. For example, when the first micro / nano structure is a pit, the precipitate may appear as a shell at the bottom of the pit; when the first micro / nano structure is a protrusion, the precipitate may appear as rod-shaped crystals or nanofibers, etc. Since some of the precipitates are not chemically bonded or otherwise connected to the first micro / nano structure, they can be removed in subsequent cleaning steps without affecting the morphology of the second micro / nano structure. As an example, the precipitate with shell-like structural features is typically conical or irregular in shape, generally appearing at the bottom of the first micrometer pit, with a thickness of 0.01–100 μm; the rod-shaped crystals may appear on the surface of the first micrometer pit and / or the first micrometer protrusion, with a diameter of 0.01–100 μm and a length of 0.01–100 μm; and the nanofibers may be densely distributed on the surface of the first micrometer pit and / or the first micrometer protrusion, with a length of approximately 1 nm–100 μm.

[0095] According to the embodiments of this application, it is necessary to select chemical reagents that can react with the metal parts according to the type of metal parts, and the reaction rate between the chemical reagents and the metal parts can be controlled by adjusting the concentration, ratio and volume of the chemical reagents, thereby better adjusting the morphology of the micro-nano structure.

[0096] According to the embodiments of this application, the chemical reagents that can be used include at least one of acids, bases, salts and their mixed solutions, such as water, hydrochloric acid, nitric acid, sulfuric acid, hydrofluoric acid, potassium hydroxide, sodium hydroxide, sodium aluminate, etc. The above chemical reagents can be used alone or mixed in a certain concentration ratio before use.

[0097] As an example, the chemical reagent comprises a mixed aqueous solution of sodium hydroxide with a molar concentration of 0.01 mol / L to 10.0 mol / L and sodium aluminate with a molar concentration of 0.01 mol / L to 10.0 mol / L. This chemical reagent with the above-mentioned composition and concentration can react with aluminum alloy parts, and the reaction rate is controllable, thereby allowing for better regulation of the first micro / nano structure to obtain a metal part with the target micro / nano structure.

[0098] In some embodiments, the molar concentration of sodium hydroxide can be 0.03–0.06 mol / L, 0.09–1.5 mol / L; more specifically, it can be 0.01 mol / L, 0.03 mol / L, 0.05 mol / L, 0.06 mol / L, 0.09 mol / L, 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, 1 mol / L, 2 mol / L, 3 mol / L, 4 mol / L, 5 mol / L, 6 mol / L, 7 mol / L, 8 mol / L, 9 mol / L, or 10 mol / L. / L, etc.; the molar concentration of sodium aluminate can be 0.03~0.06mol / L, 0.09~1.5mol / L; more specifically, it can be 0.01mol / L, 0.03mol / L, 0.05mol / L, 0.06mol / L, 0.09mol / L, 0.1mol / L, 0.2mol / L, 0.3mol / L, 0.4mol / L, 0.5mol / L, 0.6mol / L, 0.7mol / L, 0.8mol / L, 0.9mol / L, 1mol / L, 2mol / L, 3mol / L, 4mol / L, 5mol / L, 6mol / L, 7mol / L, 8mol / L, 9mol / L, 10mol / L, etc.

[0099] According to embodiments of this application, the temperature of the chemical treatment is -100℃ to 300℃, specifically 25℃ to 60℃, and more specifically 0℃, 10℃, 20℃, 25℃, 30℃, 40℃, 50℃, 60℃, 70℃, 80℃, 90℃, 100℃, 120℃, 150℃, 180℃, 200℃, 250℃, etc. Within the above temperature range, the reaction rate between the chemical reagent and the metal part is relatively fast, the processing efficiency is high, and the reaction rate is well controllable. Furthermore, by accurately adjusting the first micro / nano structure, a second micro / nano structure with controllable morphology can be obtained.

[0100] According to embodiments of this application, the chemical treatment time can be from 1 second to 120 hours, specifically from 10 minutes to 120 minutes, and more specifically from 1 second, 30 seconds, 1 minute, 10 minutes, 15 minutes, 20 minutes, 30 minutes, 40 minutes, 50 minutes, 60 minutes, 70 minutes, 80 minutes, 90 minutes, 100 minutes, 2 hours, 5 hours, 10 hours, 20 hours, 30 hours, 40 hours, 50 hours, 60 hours, 70 hours, 80 hours, 90 hours, 100 hours, 120 hours, etc. It can be understood that the longer the reaction time, the greater the range of control over the first micro / nano structure. Within the above time range, a variety of second micro / nano structures can be realized to meet the application needs of different scenarios.

[0101] It is understood that combining ultrafast laser irradiation and chemical processing can yield second micro / nano structures with diverse patterns, which can be flexibly adjusted according to actual application requirements. In some embodiments, the second micro / nano structure includes at least one of second micrometer protrusions, second micrometer pits, and combinations thereof.

[0102] According to embodiments of this application, the shape of the second micrometer protrusion includes at least one of conical, frustum-shaped, cylindrical, truncated square, and irregularly shaped protrusions.

[0103] According to an embodiment of this application, the lateral dimension of the second micrometer protrusion is 0.1μm to 1000μm, specifically such as 0.1μm, 0.2μm, 0.5μm, 1μm, 5μm, 10μm, 20μm, 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, 150μm, 200μm, 250μm, 300μm, 350μm, 400μm, 450μm, 500μm, 750μm, 1000μm, etc.

[0104] According to embodiments of this application, the shape of the second micron-sized pit includes at least one of the following: circular, elliptical, square, polygonal, groove-shaped, and irregularly shaped hole.

[0105] According to an embodiment of this application, the lateral dimension of the second micron-sized pit is 0.1μm to 1000μm, specifically such as 0.1μm, 0.2μm, 0.5μm, 1μm, 5μm, 10μm, 20μm, 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, 150μm, 200μm, 250μm, 300μm, 350μm, 400μm, 450μm, 500μm, 750μm, 1000μm, etc.

[0106] S30: Clean the surface of the metal part after the chemical treatment to obtain a metal part with a micro-nano structure on the surface.

[0107] In this step, cleaning can remove chemical reagents and precipitates from the surface of the metal parts.

[0108] Specifically, there are no particular restrictions on the cleaning method, as long as it effectively removes chemical reagents and precipitates from the surface of the metal parts. For example, ultrasonic cleaning can be performed. Specifically, the chemically treated metal parts can be placed in anhydrous ethanol or acetone for ultrasonic cleaning. After cleaning, they can be removed from the anhydrous ethanol or acetone and then allowed to air dry naturally at room temperature or dried with a dry air source.

[0109] As an example, chemically treated metal parts can be ultrasonically cleaned in anhydrous ethanol or acetone for 1 min to 120 min. The gas used to dry the surface of the metal parts is compressed air, nitrogen or argon, and the gas pressure can be set to 1 bar to 200 bar, and the blowing time can be 1 s to 300 s.

[0110] This method, based on the preparation of the first micro-nano structure on the surface of metal parts using ultrafast laser micro-nano processing, combines wet chemical treatment to perform secondary control on the morphology and contour of the first micro-nano structure on the surface of metal parts. The processing is simple, efficient, free and flexible, and can obtain micro-nano structures with controllable morphology and contour on the surface of metal parts.

[0111] In a second aspect, this application provides a metal part. According to embodiments of this application, at least a portion of the surface of the metal part has micro / nano patterns and / or structures, which are prepared by the processing methods described above. This metal part can adjust the contour and morphology of its surface micro / nano structures as needed, making it suitable for various applications such as semiconductor manufacturing, micro / nano electromechanical systems (MEMS / NEMS) manufacturing, optical component fabrication, flexible electronic devices and sensor manufacturing, functional surface preparation, and biomedical engineering.

[0112] The embodiments of this application are described in detail below.

[0113] Example 1

[0114] This embodiment modulates the morphology and contour of large-spacing micron-sized pits on the surface of 6061 aluminum alloy, including the following steps:

[0115] (1) Place the aluminum alloy sample to be processed in anhydrous ethanol and ultrasonically clean it for 10 minutes. Then take it out and blow it dry with dry nitrogen to remove surface contaminants.

[0116] (2) A femtosecond laser was used for surface processing, with a center wavelength of 343 nm, a pulse width of 500 fs, and a pulse repetition frequency of 330 kHz. The area of ​​the aluminum alloy sample used was 3 × 3 mm. 2 The thickness is 0.22 mm. The parameters used for femtosecond laser processing are: average power 15 W, scanning speed 500 mm / s, and 10 scans. The laser processing path is a 60° close-packed array of three concentric rings as units. The diameters of the concentric rings from the outside to the inside are 50 μm, 35 μm, and 15 μm, respectively. The outermost edge spacing of adjacent concentric ring units is 23 μm. The schematic diagram of the processing path is shown in Figure 1(a).

[0117] Figures 1(b) and 1(c) are scanning electron microscope (SEM) images of the micro / nano structures obtained on the aluminum alloy surface after femtosecond laser irradiation at different magnifications. As shown in the figures, the femtosecond laser irradiation produces a regularly arranged micron-sized pit structure. The pits exhibit irregular elliptical shapes, with a lateral dimension of approximately 35–50 μm, a depth of approximately 40 μm, and a pit spacing of approximately 35–40 μm. The edges of the micron-sized pits are densely covered with nanoparticles and their cluster structures, with a size of approximately 500 nm–3 μm. In addition, microcracks or microslit-like features are visible at the edges of the micron-sized pits, indicating that the pit edges are relatively rough.

[0118] (3) Prepare four 50ml mixed solutions of sodium hydroxide and sodium aluminate, each with a molar concentration of 30mol / L, in beakers. Place the samples obtained from laser processing in step (2) into four beakers containing the mixed solutions, and then place the beakers into a heating furnace. Set the heating temperature to 50℃ and set the holding time of the four beakers to 10min, 30min, 50min and 70min respectively.

[0119] Figures 2(a) and 2(b) show scanning electron microscope (SEM) images of the sample after femtosecond laser processing in step (3) at different magnifications after chemical treatment at 50°C for 10 min. Figures 2(c), 2(d), and 2(e) show SEM images of the micro / nano structures obtained after chemical treatment at 30 min, 50 min, and 70 min, respectively, in step (3). As can be seen from Figures 2(a) and 2(b), after chemical treatment at 50°C for 10 min, the nanoparticles and their cluster structures on the surface of the micro-pits in step (2) are significantly removed. At the same time, the microcracks or micro-slits on the edges and inner walls of the micro-pits disappear, the edges of the micro-pits become sharper and smoother, the outline of the micro-pits becomes clearer, and the size of the micro-pits increases, with the lateral dimension increasing to about 50–55 μm and the pit spacing decreasing to about 18–23 μm. The outline of the micro-pits transitions from an irregular ellipse before chemical treatment to a perfect circle. As shown in Figures 2(c) and 2(d), after chemical treatment at 50℃ for 30 min and 50 min, the size of the micron-sized pits further increased. After 50 min of chemical treatment, the lateral dimension of the micron-sized pits increased to approximately 60–65 μm, the pit spacing decreased to approximately 8–13 μm, and shell-like precipitates appeared at the bottom of the pits. The height of the shell-like precipitates gradually increased with the increase of the holding time of the chemical treatment. When the holding time was 50 min, the height of the shell-like precipitates was approximately 5–10 μm, and the thickness was approximately 1–3 μm. As shown in Figure 2(e), after chemical treatment at 50℃ for 70 min, the outline of the micron-sized pits was close to a perfect circle, the lateral dimension of the pits increased to approximately 65–70 μm, the pit spacing further decreased to approximately 3–8 μm, and adjacent pits almost merged. Meanwhile, rod-shaped crystals further precipitated on the surface of the shell-like precipitate within the micron-depression, with a diameter of approximately 0.5–3 μm and a length of approximately 0.5–5 μm; the surface of the micron-depression structure is covered with densely distributed nanofibrils, with a length of approximately 200–500 nm.

[0120] (4) Place the sample obtained from the chemical treatment in step (3) in anhydrous ethanol for ultrasonic cleaning for 10 minutes, then take it out and air dry it at room temperature.

[0121] Figures 3(a) to 3(d) The images shown are scanning electron microscope (SEM) images of the patterned micro / nano structures on the surface of samples that underwent chemical treatment at 50°C for 10 min, 30 min, 50 min, and 70 min as described in step (3) and were then ultrasonically cleaned as described in step (4). As can be seen from the images, after ultrasonic cleaning, the shell-like precipitates within the micrometer-sized pits discovered in step (3), the rod-like crystals precipitated on the surface of the shell-like precipitates, and the dense nanofibers covering the surface of the micrometer-sized pits have all been removed.

[0122] Figure 4 The roundness (R) of the micron-sized pits obtained by the femtosecond laser processing in step (2) is... max / R min The curve shows the change in the chemical treatment holding time (Time) described in step (3). As can be seen from the figure, with the increase of the chemical treatment holding time, the major axis R of the elliptical-shaped pit... max With the short axis R min The ratio gradually approaches 1, meaning that its shape gradually changes from an irregular ellipse to a perfect circle, thus achieving the control of the morphological contour of the patterned micro-nano structure on the aluminum alloy surface.

[0123] Example 2

[0124] This embodiment controls the morphology and contour of small-pitch micron-sized pits on the surface of 6061 aluminum alloy, including the following steps:

[0125] (1) Place the aluminum alloy sample to be processed in anhydrous ethanol and ultrasonically clean it for 10 minutes. Then take it out and blow it dry with dry nitrogen to remove surface contaminants.

[0126] (2) A femtosecond laser was used for surface processing, with a center wavelength of 343 nm, a pulse width of 500 fs, and a pulse repetition frequency of 330 kHz. The area of ​​the aluminum alloy sample used was 3 × 3 mm. 2 The thickness is 0.22 mm. The parameters used for femtosecond laser processing are: average power 15 W, scanning speed 500 mm / s, and 10 scans. The laser processing path is a 60° close-packed array of three concentric rings as units. The diameters of the concentric rings from the outside to the inside are 50 μm, 35 μm, and 15 μm, respectively. The outermost edge spacing of adjacent concentric ring units is 5 μm. The schematic diagram of the processing path is shown in Figure 5(a).

[0127] Figures 5(b) and 5(c) are scanning electron microscope (SEM) images of the micro / nano structures obtained on the aluminum alloy surface after femtosecond laser irradiation at different magnifications. As shown in the figures, the femtosecond laser irradiation produces a regularly arranged micron-sized pit structure with irregular elliptical shapes. The lateral dimensions of the pits are approximately 35–50 μm, the depth is approximately 40 μm, and the spacing between the pits is approximately 15–20 μm. The edges of the micron-sized pits are densely covered with nanoparticles and their cluster structures, with a size of approximately 500 nm–3 μm. In addition, microcracks or microslits are visible at the edges of the micron-sized pits, indicating that the pit edges are relatively rough.

[0128] (3) Prepare a 50ml mixed solution of sodium hydroxide and sodium aluminate, both with a molar concentration of 30mol / L, in a beaker. Place the sample obtained from laser processing in step (2) into the beaker containing the mixed solution, and then place the beaker into a heating furnace. Set the heating temperature to 50℃ and the holding time to 60min.

[0129] (4) Place the sample obtained from the chemical treatment in step (3) in anhydrous ethanol for ultrasonic cleaning for 10 minutes, then take it out and air dry it at room temperature.

[0130] Figures 5(d) and 5(e) show scanning electron microscope (SEM) images of the micro-nano structures on the surface of the micro-pits obtained by femtosecond laser processing in step (2) after chemical treatment in step (3) and ultrasonic cleaning in step (4) at different magnifications. As can be seen from the figures, the micro-pits obtained by femtosecond laser processing have expanded to a tightly interconnected state after chemical treatment for 60 min and ultrasonic cleaning. The shape of the pits has changed from an irregular ellipse to a near-hexagonal honeycomb structure. The nanoparticles and their cluster structures on the surface of the micro-pits in step (2) have been significantly removed. At the same time, the microcracks or micro-slits on the edges and inner walls of the micro-pits have disappeared. The edges of the micro-pits are sharper and smoother, and the outline of the micro-pits is clearer.

[0131] Example 3

[0132] This embodiment controls the contour of micron-sized protrusions on the surface of 6061 aluminum alloy, including the following steps:

[0133] (1) Place the aluminum alloy sample to be processed in anhydrous ethanol and ultrasonically clean it for 10 minutes. Then take it out and blow it dry with dry nitrogen to remove surface contaminants.

[0134] (2) A femtosecond laser was selected for surface processing, with a center wavelength of 343 nm, a pulse width of 500 fs, and a pulse repetition frequency of 330 kHz. The area of ​​the aluminum alloy sample used was 3 × 3 mm. 2 The thickness is 0.22mm.

[0135] The parameters used for femtosecond laser processing are: average power 14W, scanning speed 500mm / s, and 15 scans. The laser processing path is a vertical intersecting line with a spacing of 25μm between adjacent lines. A schematic diagram of the processing path is shown in Figure 6(a).

[0136] Figure 6(b) is a scanning electron microscope image of the micro / nano structure obtained on the aluminum alloy surface after femtosecond laser irradiation. As shown in the figure, the femtosecond laser irradiation produces a regularly arranged micron-sized protrusion structure. The lateral dimension of the micron-sized protrusion is about 20-25 μm, and the height is about 35 μm. The surface of the micron-sized protrusion is densely covered with nanoparticles and their cluster structures, with a size of about 200 nm to 3 μm.

[0137] (3) Prepare three 50ml mixed solutions of sodium hydroxide and sodium aluminate, each with a molar concentration of 30mol / L, in beakers. Place the samples obtained from laser processing in step (2) into three beakers containing the mixed solutions, and then place the beakers into a heating furnace. Set the heating temperature to 50℃ and set the holding time of the three beakers to 10min, 20min and 30min respectively.

[0138] Figures 6(c) to 6(e) The images show scanning electron microscope (SEM) images of the micro / nano structures on the surface of the micron-sized protrusions obtained by femtosecond laser processing in step (2) after chemical treatment for 10 min, 20 min, and 30 min as described in step (3). As can be seen from the images, after 10 min of chemical treatment, the nanoparticles and their cluster structures covering the surface of the micron-sized protrusions obtained by femtosecond laser processing are significantly removed. Simultaneously, the outline of the micron-sized protrusions changes from a frustum shape to a quadrangular pyramid shape. Furthermore, as the holding time of the chemical treatment increases, the lateral size and height of the micron-sized protrusions gradually decrease. After 30 min of chemical treatment, the depressions around the micron-sized protrusions expand, forming micron-sized pits, within which shell-like precipitates appear.

[0139] Example 4

[0140] This embodiment controls the morphology and contour of the composite pattern of micron-sized pits and protrusions on the surface of 6061 aluminum alloy, including the following steps:

[0141] (1) Place the aluminum alloy sample to be processed in anhydrous ethanol and ultrasonically clean it for 10 minutes. Then take it out and blow it dry with dry nitrogen to remove surface contaminants.

[0142] (2) A femtosecond laser was selected for surface processing, with a center wavelength of 343 nm, a pulse width of 500 fs, and a pulse repetition frequency of 330 kHz. The area of ​​the aluminum alloy sample used was 3 × 3 mm. 2 The thickness is 0.22mm.

[0143] The parameters used for femtosecond laser processing are: average power 14W, scanning speed 500mm / s, and 15 scans. The laser processing path is a 60° close-packed array with individual rings as units. The diameter of the rings is 43μm, and the outermost edge spacing between adjacent concentric ring units is 30μm. The schematic diagram of the processing path is shown in Figure 7(a).

[0144] Figure 7(b) is a scanning electron microscope image of the micro / nano structure obtained on the aluminum alloy surface after femtosecond laser irradiation. As shown in the figure, the femtosecond laser irradiation produces a regular array of composite structures consisting of micron-sized pits and internal micron-sized protrusions. The outline of the micron-sized pits is an irregular rounded rectangle with a lateral dimension of approximately 45–48 μm. The outline of the micron-sized protrusions is a frustum shape with a lateral dimension of approximately 20–25 μm. The depth of the micron-sized pits and the height of the micron-sized protrusions are approximately 40 μm, and the spacing between the micron-sized pits is approximately 30 μm. The micron-sized pits are densely covered with nanoparticles and their cluster structures, with a size of approximately 500 nm to 3 μm. In addition, microcracks or micro-slits are visible at the edges of the micron-sized pits, and the edges of the pits are relatively rough.

[0145] (3) Prepare three 50ml mixed solutions of sodium hydroxide and sodium aluminate, each with a molar concentration of 30mol / L, in beakers. Place the laser-processed sample obtained in step (2) into three beakers containing the mixed solution, and then place the beakers into a heating furnace. Set the heating temperature to 50℃ and the holding time for the three beakers to 30min, 50min and 70min respectively.

[0146] (4) Place the sample obtained from the chemical treatment in step (3) in anhydrous ethanol for ultrasonic cleaning for 10 minutes, then take it out and air dry it at room temperature.

[0147] Figures 7(c) to 7(e) The images shown are scanning electron microscope (SEM) images of the micron-shaped pit / protrusion composite structure obtained by femtosecond laser processing in step (2) after chemical treatment for 30 min, 50 min, and 70 min as described in step (3), followed by ultrasonic cleaning as described in step (4). As can be seen from the images, after chemical treatment for 30 min, the nanoparticles and their cluster structures around the micron-shaped pits are significantly removed. Simultaneously, the microcracks or micro-slits on the edges and inner walls of the micron-shaped pits disappear, the edges of the micron-shaped pits become sharper and smoother, and the contours of the micron-shaped pits become clearer. As the chemical treatment holding time increases, the micron-sized pits gradually expand, and the outline of the micron-sized pits gradually transitions from an irregular rounded rectangle before chemical treatment to a perfect circle. After 70 minutes of chemical treatment, the lateral dimension of the micron-sized pits increases to about 67-70 μm, and the pit spacing decreases to about 3-6 μm. As the chemical treatment holding time increases, the height and lateral dimension of the micron-sized protrusions in the pits gradually decrease. After 70 minutes of chemical treatment, the micron-sized protrusions basically disappear, and the structural form of the sample surface changes to a regularly arranged near-perfect circular array of micron-sized pits.

[0148] Example 5

[0149] In step (2) of Example 4, the spacing between the rings was adjusted to 10 μm, and the remaining conditions were the same as in Example 4. The processing results are as follows:

[0150] Figure 8(a) is a scanning electron microscope image of the micro / nano structure obtained on the aluminum alloy surface after femtosecond laser irradiation. As can be seen from the figure, the femtosecond laser irradiation still produces a regular array of composite structures formed by the combination of micron-sized pits and their internal micron-sized protrusions. The depth of the micron-sized pits and the height and lateral dimensions of the micron-sized protrusions are the same as in Example 4, but the spacing between the micron-sized pits becomes about 10 μm. The micron-sized pits are densely covered with nanoparticles and their cluster structures, with a size of about 500 nm to 3 μm. In addition, microcracks or micro-slit-like features can be seen at the edges of the micron-sized pits, and the edges of the pits are relatively rough.

[0151] Figures 8(b) to 8(d) The images shown are scanning electron microscope (SEM) images of the micron-sized pit / protrusion composite structure obtained by femtosecond laser processing in step (2) after chemical treatment for 30 min, 50 min and 70 min in step (3), and then ultrasonic cleaning in step (4). As shown in the figure, after 30 minutes of chemical treatment, the micro-pit / protrusion composite structure obtained by femtosecond laser processing transforms the outline of the micro-pits from an irregular rounded rectangle to a near-circular shape, with a lateral dimension of approximately 50–53 μm. The micro-protrusions within the pits change from a frustum shape to a cone shape, and the microcracks or micro-slits on the edges and inner walls of the micro-pits disappear, making the edges of the micro-pits sharper and smoother, and the outlines of the micro-pits clearer. As the holding time of the chemical treatment continues to increase, the micro-pits gradually achieve tight interconnection, transitioning from a circular shape to a hexagonal honeycomb structure. The lateral dimension and height of the micro-protrusions gradually decrease, and shell-like structures formed by precipitate accumulation appear on the inner walls of the micro-pits and the bottom of the outer sides of the micro-protrusions. The thickness of the shell-like precipitates is approximately 1–3 μm. After 70 minutes of chemical treatment, the micro-protrusions essentially disappear, and the structure on the sample surface becomes a regularly arranged hexagonal honeycomb array of micro-pits.

[0152] Example 6

[0153] This embodiment controls the morphology and contour of micron-sized pits with varying spacing gradients on the surface of 6061 aluminum alloy, including the following steps:

[0154] (1) Place the aluminum alloy sample to be processed in anhydrous ethanol and ultrasonically clean it for 10 minutes. Then take it out and blow it dry with dry nitrogen to remove surface contaminants.

[0155] (2) A femtosecond laser was selected for surface processing, with a center wavelength of 343 nm, a pulse width of 500 fs, and a pulse repetition frequency of 330 kHz. The area of ​​the aluminum alloy sample used was 3 × 3 mm. 2 The thickness is 0.22mm.

[0156] The parameters used for femtosecond laser processing are: average power 15W, scanning speed 500mm / s, and 15 scans. The laser processing path is a 60° close-packed array of three concentric rings as units. The diameters of the concentric rings from the outside to the inside are 50μm, 35μm, and 15μm, respectively. The spacing between the outermost edges of adjacent concentric ring units increases by 10μm to achieve a gradient change in spacing, ranging from 10 to 70μm. The schematic diagram of the processing path is shown in Figure 9(a).

[0157] Figure 9(b) is a scanning electron microscope image of the micro / nano structure obtained on the aluminum alloy surface after femtosecond laser irradiation. As shown in the figure, the femtosecond laser irradiation produces a micro-pit structure with a gradient spacing. The outline of the micro-pit is an irregular ellipse, with a lateral dimension of approximately 45–48 μm and a depth of approximately 40 μm. The pit spacing varies from 10 to 70 μm. The micro-pits are densely covered with nanoparticles and their cluster structures, with a size of approximately 500 nm to 3 μm.

[0158] (3) Prepare a 50ml mixed solution of sodium hydroxide and sodium aluminate, both with a molar concentration of 30mol / L, in a beaker. Place the sample obtained from laser processing in step (2) into the beaker containing the mixed solution, and then place the beaker in a heating furnace. Set the heating temperature to 50℃ and the holding time to 60min. After the holding time is completed, remove the sample and ultrasonically clean it in anhydrous ethanol for 10min. Then, place the sample again into a freshly prepared 50ml mixed solution of sodium hydroxide and sodium aluminate, both with a molar concentration of 30mol / L, and place the beaker in a heating furnace. Set the heating temperature to 60℃ and the holding time to 40min.

[0159] (4) Place the sample obtained from the chemical treatment in step (3) in anhydrous ethanol for ultrasonic cleaning for 10 minutes, then take it out and air dry it at room temperature.

[0160] Figure 9(c) shows the scanning electron microscope (SEM) image of the micron-shaped pits with varying spacing obtained by femtosecond laser processing in step (2), after two consecutive chemical treatments in step (3) and ultrasonic cleaning in step (4). As can be seen from the figure, after two consecutive chemical treatments, the originally irregularly shaped micron-shaped pits eventually become hexagonal honeycomb structures. Due to the different spacing between the micron-shaped pits in different parts, the pits can expand to different extents during chemical treatment, resulting in a hexagonal honeycomb structure with varying size gradients and a honeycomb side length of 30–65 μm.

[0161] Example 7

[0162] This embodiment controls the morphology profile of micron-sized pits with varying diameters on the surface of 6061 aluminum alloy, including the following steps:

[0163] (1) Place the aluminum alloy sample to be processed in anhydrous ethanol and ultrasonically clean it for 10 minutes. Then take it out and blow it dry with dry nitrogen to remove surface contaminants.

[0164] (2) A femtosecond laser was selected for surface processing, with a center wavelength of 343 nm, a pulse width of 500 fs, and a pulse repetition frequency of 330 kHz. The area of ​​the aluminum alloy sample used was 3 × 3 mm. 2 The thickness is 0.22mm.

[0165] The parameters used for femtosecond laser processing are: average power 15W, scanning speed 500mm / s, and 15 scans. The laser processing path is a 90° array of multiple concentric rings as units. The innermost ring of the concentric ring unit has a diameter of 20μm, and the diameter of the subsequent rings increases by 10μm each time. The diameter of the outermost ring also increases by 10μm each time to achieve a gradient change, ranging from 50 to 130μm. The outermost edge spacing of adjacent concentric ring units is 20μm. The schematic diagram of the processing path is shown in Figure 10(a).

[0166] Figure 10(b) is a scanning electron microscope image of the micro / nano structure obtained on the aluminum alloy surface after femtosecond laser irradiation. As shown in the figure, the femtosecond laser irradiation produces a micro-pit structure with a diameter gradient. The outline of the micro-pit is an irregular ellipse. Some incompletely ablated protrusions appear inside the larger diameter micro-pits. The lateral dimensions of the micro-pits are approximately 50–130 μm, the depth is approximately 40 μm, and the pit spacing is 20 μm. The micro-pits are densely covered with nanoparticles and their cluster structures, with a size of approximately 500 nm–3 μm.

[0167] (3) Prepare a 50ml mixed solution of sodium hydroxide and sodium aluminate, both with a molar concentration of 30mol / L, in a beaker. Place the sample obtained from laser processing in step (2) into the beaker containing the mixed solution, and then place the beaker in a heating furnace. Set the heating temperature to 50℃ and the holding time to 60min. After the holding time is completed, remove the sample and ultrasonically clean it in anhydrous ethanol for 10min. Then, place the sample again into a freshly prepared 50ml mixed solution of sodium hydroxide and sodium aluminate, both with a molar concentration of 30mol / L, and place the beaker in a heating furnace. Set the heating temperature to 60℃ and the holding time to 40min.

[0168] (4) Place the sample obtained from the chemical treatment in step (3) in anhydrous ethanol for ultrasonic cleaning for 10 minutes, then take it out and air dry it at room temperature.

[0169] Figure 10(c) shows the scanning electron microscope (SEM) image of the micron-shaped pits with varying diameters obtained by femtosecond laser processing in step (2), after two consecutive chemical treatments in step (3) and ultrasonic cleaning in step (4). As can be seen from the figure, after two consecutive chemical treatments, the originally irregularly shaped micron-shaped pits become more regular in shape, approaching perfect circles, and are in close contact with each other; the protruding structures inside the large-diameter pits caused by insufficient laser ablation are gradually removed during the chemical treatment; in addition, since the micron-shaped pits are arranged in a 90° array, the pits do not form a hexagonal honeycomb structure after chemical treatment, but rather a quadrilateral grid structure with varying size gradients, with the quadrilateral side lengths ranging from 60 to 150 μm.

[0170] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0171] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0172] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for patterning metal surfaces using micro / nano fabrication, characterized in that, include: Following a predetermined path, an ultrafast laser is used to irradiate the surface of a metal part to form a first micro / nano structure on the surface of the metal part. The surface of the metal part on which the first micro-nano structure is formed is chemically treated with chemical reagents to change the first micro-nano structure and form a second micro-nano structure on the surface of the metal part. The surface of the metal part after the chemical treatment is cleaned to obtain a metal part with a micro-nano structure on the surface.

2. The metal surface patterning micro / nano fabrication method according to claim 1, characterized in that, The metal part satisfies at least one of the following conditions: The metal components include at least one of the following: gold, silver, platinum, aluminum and aluminum alloys, magnesium and magnesium alloys, zinc and zinc alloys, copper and copper alloys, titanium and titanium alloys, tungsten and tungsten alloys, nickel and nickel alloys, manganese and manganese alloys, iron, and steel. The metal component may be in the form of at least one of a metal block, a metal foil, a metal mesh, or a metal foam.

3. The metal surface patterning micro / nano fabrication method according to claim 1, characterized in that, The ultrafast laser satisfies at least one of the following conditions: The ultrafast laser is at least one of ultraviolet, infrared, and visible light; The wavelength of the ultrafast laser is 100nm to 2000nm; The pulse width of the ultrafast laser is 1 fs to 30 ps; The pulse frequency of the ultrafast laser is 1 Hz to 1 GHz; The average power of the ultrafast laser is 1mW to 10kW.

4. The metal surface patterning micro / nano fabrication method according to claim 1, characterized in that, The predetermined path includes at least one of the following: point, parallel line, intersecting line, loop, concentric circle, spiral, meander, and free pattern.

5. The metal surface patterning micro / nano fabrication method according to claim 1, characterized in that, The first micro / nano structure includes a first micrometer structure and a first nanostructure located on the first micrometer structure; The first nanostructure includes at least one of nanoparticles, nanowaves, nanofibers, nanosynapses, and nanoparticle clusters; The first micron structure satisfies at least one of the following conditions: The first micron structure includes at least one of a first micron protrusion, a first micron pit, and combinations thereof; The shape of the first micrometer protrusion includes at least one of the following: conical, frustum-shaped, cylindrical, truncated square, and irregularly shaped protrusions; The lateral dimension of the first micrometer protrusion is 0.1 μm to 1000 μm; The shape of the first micrometer-sized pit includes at least one of the following: circular, elliptical, square, polygonal, groove-shaped, and irregularly shaped hole; The lateral dimension of the first micrometer-sized pit is 0.1 μm to 1000 μm.

6. The method for patterning metal surfaces using micro / nano fabrication according to claim 1, characterized in that, The chemical treatment satisfies at least one of the following conditions: The chemical reagents include at least one of acids, bases, salts, and their mixed solutions; The temperature for the chemical treatment is -100℃ to 300℃; The chemical treatment time is from 1 second to 120 hours.

7. The metal surface patterning micro / nano fabrication method according to claim 5, characterized in that, The changes in the first micro / nano structure include at least one of the following: 1) The first nanostructure is removed, and the surface of the first microstructure becomes smoother; 2) The microcracks or microgaps at the edge of the first micron-sized pit contour are removed, making the edge of the first micron-sized pit contour clearer; 3) The first micrometer-sized protrusion gradually disappears; 4) The outline of the first micrometer pit gradually expands and the depth of the first micrometer pit gradually increases; 5) The shape of the first micrometer-sized pit changes; 6) Precipitates appear on the surface of the first micron protrusion or the first micron pit.

8. The method for patterning metal surfaces using micro / nano fabrication according to claim 1, characterized in that, The second micro / nano structure includes at least one of a second micrometer protrusion, a second micrometer pit, and combinations thereof; The second micro / nano structure satisfies at least one of the following conditions: The shape of the second micrometer protrusion includes at least one of the following: conical, frustum-shaped, cylindrical, truncated square, and irregularly shaped protrusions; The lateral dimension of the second micrometer protrusion is 0.1 μm to 1000 μm; The shape of the second micrometer pit includes at least one of the following: circular, elliptical, square, polygonal, groove-shaped, and irregularly shaped hole; The lateral dimension of the second micrometer pit is 0.1μm to 1000μm.

9. A metal part, characterized in that, At least a portion of the surface of the metal part has micro-nano patterns and / or structures, which are prepared by the metal surface patterning micro-nano processing method according to any one of claims 1 to 8.

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