A high-temperature radiative cooling micro-groove-micro-nano-papilla structure with top-projection high reflection, a manufacturing process and a radiative cooling device

Abstract

This invention discloses a high-temperature radiative cooling microgroove-micro / nanoplasty structure with high top-projection reflectivity, its manufacturing process, and a radiative cooling device, belonging to the field of heat transfer technology. The structure includes a grooved substrate, a high-reflectivity coating, and a micro / nanoplasty radiative structure. The grooved substrate has grooves on its surface; the grooves are arranged in a unidirectional comb-like array or an orthogonal array on the substrate surface; the top-projection surface of the grooves is coated with a high-reflectivity coating; the non-top-projection surface of the grooves is covered with a micro / nanoplasty radiative structure; the micro / nanoplasty radiative structure includes a micrometer-scale core papilla, micrometer-scale multi-level papillae clustered on the surface of the core papilla, and nanometer-scale particles densely distributed on the surface of the multi-level papillae. This invention achieves high reflectivity of solar radiation through the high-reflectivity coating on the top-projection surface and enhances infrared radiation emission by utilizing the hierarchical micro / nanoplasty radiative structure on the non-top-projection surface, significantly improving net radiative cooling power.

Description

Technical Field

[0001] This invention belongs to the field of heat transfer technology and relates to a radiation cooling structure, particularly to a high-temperature radiation cooling micro-groove-micro-nanoplasty structure with high top projection reflectivity, its manufacturing process, and a radiation cooling device. Background Technology

[0002] The global greenhouse effect is increasingly impacting the Earth, causing temperatures to rise annually. The extraction and use of fossil fuels exacerbate this effect, and energy consumption, such as for air conditioning, further intensifies it. Therefore, a new cooling method—radiative cooling—has been discovered in recent years. It consumes no additional energy and produces no greenhouse gases like carbon dioxide, while spontaneously releasing heat. This passive energy-saving method is widely used in aerospace, electronics, and construction.

[0003] The core of radiative cooling is to selectively direct the infrared radiation generated by the thermal vibrations within an object through an 8-13 μm transparent window in the atmosphere to outer space—the ultimate cold source—while simultaneously maximizing the reflection of sunlight to achieve net cooling. Microscopically, the vibration of charged particles within the material converts thermal motion into photon radiation; macroscopically, the energy conservation inequality must be satisfied, meaning the emitted radiation power must exceed the sum of absorbed solar radiation and atmospheric back radiation. Therefore, the material must simultaneously achieve two opposing optical effects within the same structure: near-perfect reflection in the visible-near-infrared band to counteract solar heating, and near-perfect absorption / emission in the infrared window band to release heat. Sheffield et al. designed and fabricated a sawtooth structure that possesses both of these functions; however, due to its manufacturing process, designing such a structure is costly, and the manufacturing process and structure are limited. Furthermore, this structure may fail at high temperatures. Therefore, there is an urgent need for a high-temperature radiative cooling structure that can be fabricated without the need for precision instruments while reducing costs. Summary of the Invention

[0004] This invention provides a high-temperature radiation cooling microgroove-micro-nanoplastic structure with high top projection reflectivity, a manufacturing process, and a radiation cooling device to overcome the deficiencies of the prior art.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a high-temperature radiation cooling microgroove-micro / nanopapillary structure with high top-projection reflectivity, comprising a grooved substrate, a high-reflectivity coating, and a micro / nanopapillary radiation structure; the grooved substrate is a substrate with grooves on its surface; the grooves are arranged in a unidirectional comb-like array or an orthogonal array on the substrate surface; the high-reflectivity coating is provided on the top-projection surface of the grooves; the micro / nanopapillary radiation structure is provided on the non-top-projection surface of the grooves; the micro / nanopapillary radiation structure comprises a micrometer-scale core papilla, micrometer-scale multi-level papillae clustered on the surface of the core papilla, and nanometer-scale particles densely distributed on the surface of the multi-level papillae. Wherein, the top-projection surface refers to the surface visible from directly above, and the non-top-projection surface refers to the surface not visible from directly above.

[0006] To optimize the above technical solution, the specific measures also include: Furthermore, the trenches of the grooved substrate are sawtooth, rectangular, or dovetail-shaped; the sawtooth trench is composed of a sawtooth trench inclined surface and a sawtooth trench steep wall surface, with a sawtooth cross-section; the sawtooth trench inclined surface is provided with the high-reflectivity coating, and the sawtooth trench steep wall surface is provided with the micro-nano papillary radiation structure; the rectangular trench is composed of a rectangular trench bottom surface and a rectangular trench steep wall surface, with a rectangular cross-section; the rectangular trench bottom surface and the rectangular trench body top surface are provided with the high-reflectivity coating, and the rectangular trench steep wall surface is provided with the micro-nano papillary radiation structure; the dovetail-shaped trench is composed of a dovetail-shaped trench bottom surface and a dovetail-shaped trench steep wall surface, with a dovetail-shaped cross-section; the dovetail-shaped trench bottom surface and the dovetail-shaped trench body top surface are provided with the high-reflectivity coating, and the dovetail-shaped trench steep wall surface is provided with the micro-nano papillary radiation structure.

[0007] Further, the serrated grooves have a spacing of 0.1~10 mm and a height of 0.1~10 mm. The angle between the inclined surface of the serrated groove and the surface of the grooved base is 10~60°, and the angle between the steep wall of the serrated groove and the surface of the grooved base is 90° or deviated inward by no more than 20° from the inclined surface of the serrated groove. The rectangular grooves have a spacing of 0.1~10 mm and a height of 0.1~10 mm. The bottom surface of the rectangular groove is coplanar or parallel to the surface of the grooved base, and the angle between the steep wall of the rectangular groove and the surface of the grooved base is 90°. The dovetail grooves have a spacing of 0.1~10 mm and a height of 0.1~10 mm. The bottom surface of the dovetail groove is coplanar or parallel to the surface of the grooved base, and the angle between the steep wall of the dovetail groove and the surface of the grooved base is 60~70°.

[0008] Furthermore, the portion of the surface of the grooved substrate without grooves is also provided with the high-reflectivity coating.

[0009] Furthermore, the thickness of the high-reflectivity coating is 100~1000 nm.

[0010] Furthermore, in the micro / nano papillary radiation structure, the diameter of the core papilla is 6~12 μm, the diameter of the multi-level papilla is 2~4 μm, the height is 3~6 μm, the size of the particles is 10~50 nm, and the cross-section of the micro / nano papillary radiation structure is bear paw shaped.

[0011] Furthermore, the materials of the trench-shaped substrate, the high-reflectivity coating, and the micro / nano papillary radiation structure are all metals.

[0012] Furthermore, the materials of the grooved substrate and the micro / nano papillary radiation structure are stainless steel, copper, titanium, or high-temperature alloys; the material of the high-reflectivity coating is gold, silver, or platinum; and the materials of the grooved substrate and the micro / nano papillary radiation structure are the same.

[0013] Secondly, the present invention also provides a manufacturing process for the above-mentioned high-temperature radiation cooling microgroove-micro-nanoplasty structure with high top projection reflectivity, comprising the following steps: S1: using electrolytic wire cutting technology to process unidirectional comb-shaped arrays or orthogonal arrays of grooves on the substrate surface to form the grooved substrate; for orthogonal arrays of grooves, first process unidirectional comb-shaped arrays of grooves, then rotate the substrate 90° and continue to process orthogonal arrays of grooves, thus forming orthogonal arrays of grooves; the spacing, height, inclined surface, steep wall surface, etc. of the top of the sawtooth, rectangular, or dovetail-shaped groove body are all controlled by the two-dimensional motion trajectory of the electrolytic wire cutting plane; S2: The grooved substrate obtained in S1 is placed on a coating platform, and the high-reflectivity coating is obtained by magnetron sputtering, electron beam evaporation, or chemical / electrochemical coating processes; S3: The grooved substrate with the high-reflectivity coating obtained in S2 is tilted at 45~85° so that the non-top projection surface is exposed to the processing area. Nanosecond, picosecond, or femtosecond pulsed lasers are used to perform line-by-line scanning ablation on the non-top projection surface to obtain a micro-nano papillary radiation structure; For grooves arranged in an orthogonal array, after the first processing, the grooved substrate is rotated 90° and the non-top projection surface in another orthogonal direction is scanned and ablated line by line to construct a micro-nano papillary radiation structure in an orthogonal direction.

[0014] Thirdly, the present invention also provides a radiation cooling device comprising the above-mentioned high-temperature radiation cooling microgroove-micro-nanoplastic structure with high top projection reflectivity.

[0015] The beneficial effects of this invention are as follows: This invention provides a high-temperature radiation cooling micro-groove-micro-nanoplastic structure with high top projection reflectivity. By depositing a high-reflectivity coating on the top projection surface of the groove, solar radiation is effectively reflected. At the same time, a hierarchical micro-nanoplastic radiation structure is constructed on the vertical or near-vertical steep wall surface. The light trapping effect and surface plasmon polaritons enhance the absorption / emissivity of the infrared band, especially the 8~13 μm atmospheric window. The combination of these two factors achieves spatial functional separation between the top reflecting solar heat and the sidewall radiating object heat, significantly improving the net radiation cooling power.

[0016] Specifically, the micro / nanoplastic radiating structures formed by laser phase explosion and fusion effects are spatially randomly staggered and hierarchically distributed, forming a spatially overlapping nanometer to micrometer scale. After incident electromagnetic waves penetrate into the structure, they undergo multiple internal reflections within the slits and cavities, propagating back and forth, effectively extending the optical transmission path and creating a light-trapping effect. Simultaneously, the multiple reflections and light-trapping effects within the slits and cavities, combined with the enhanced absorption by localized surface plasmon resonances at the micro / nanoplastic tips, further strengthen the structure's absorption / radiative heat dissipation in the mid-infrared band. While maximizing the effective projected area of ​​the reflective surface, the staggered spatial arrangement of the micro / nanoplasts, along with the concave and steeply oriented configuration, suppresses the absorption of sunlight in the ultraviolet, visible, and near-infrared direct bands. Furthermore, the close proximity of the high-reflectivity coating to the micro / nanoplastic radiating structures allows the solar radiation heat captured by the high-reflectivity coating to be rapidly transferred to the micro / nanoplastic radiating structures along the shortest heat conduction path, thereby efficiently enhancing the structure's radiative heat transfer and evaporative heat dissipation performance. Furthermore, the trench structure increases the actual heat dissipation area, while the capillary effect of the micro-nano papillary radiation structure can assist evaporative cooling in the presence of the working fluid, achieving synergistic enhancement of radiation cooling and convection / evaporation.

[0017] The trench-shaped substrate and the micro / nano papillary radiation structure of this invention are made of the same material, namely stainless steel, copper, titanium, high-temperature alloys and other metal materials, to avoid coating peeling or oxidation failure at high temperatures. At the same time, the high-reflectivity coating is made of precious metal materials such as gold, silver and platinum, which have good thermal stability and oxidation resistance. The overall structure has excellent high-temperature resistance and is suitable for high-temperature working conditions.

[0018] This invention employs electrolytic wire cutting to fabricate macro / mesoscale trench arrays, offering high efficiency and eliminating the heat-affected zone. It utilizes laser direct writing technology to fabricate hierarchical micro / nano papillary radiating structures on steep walls, eliminating the need for expensive equipment such as photolithography and vacuum deposition. The manufacturing process is simple, low-cost, highly compatible, and easily scalable. Furthermore, the trench structure, size, and arrangement can be flexibly designed according to actual heat dissipation requirements and processing conditions to accommodate selective emission at different wavelengths and incident light from different directions. Attached Figure Description

[0019] Figure 1This is a schematic diagram of the high-temperature radiation cooling microgroove-micro-nanoplasty structure with high top projection reflectivity in Example 1. Figure 2 This is a schematic diagram of the micro / nano papillary radiation structure of Example 1; Figure 3 This is a focused ion beam morphology diagram of the micro / nano papillary radiation structure in Example 1; Figure 4 This is a schematic diagram of the principle of the high-temperature radiation cooling micro-groove-micro-nanoplasty structure with high top projection reflectivity in Example 1. Figure 5 This is a schematic diagram of the high-temperature radiation cooling microgroove-micro-nanoplasty structure with high top projection reflectivity in Example 2. Figure 6 This is a schematic diagram of the high-temperature radiation cooling microgroove-micro-nanoplasty structure with high top projection reflectivity in Example 3. Figure 7 This is a schematic diagram of the high-temperature radiation cooling microgroove-micro-nanoplasty structure with high top projection reflectivity in Example 4. Figure 8 This is a schematic diagram of the high-temperature radiation cooling microgroove-micro-nanoplasty structure with high top projection reflectivity in Example 5. Figure 9 This is a schematic diagram of the high-temperature radiation cooling microgroove-micro-nanoplasty structure with high top projection reflectivity in Example 6. The labels in the attached diagram are as follows: 1. Groove-shaped substrate; 11. Dovetail-shaped groove; 111. Bottom surface of dovetail-shaped groove; 112. Steep wall surface of dovetail-shaped groove; 113. Top surface of dovetail-shaped groove body; 12. Rectangular groove; 121. Bottom surface of rectangular groove; 122. Steep wall surface of rectangular groove; 123. Top surface of rectangular groove body; 13. Serrated groove; 131. Inclined surface of serrated groove; 132. Steep wall surface of serrated groove; 14. Part without serrated groove; 2. High-reflectivity coating; 3. Micro / nano papillary radiation structure; 31. Core papillary; 32. Multilevel papillary. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0021] Example 1 This embodiment provides a high-temperature radiation cooling microgroove-micro-nanoplasty structure with high top projection reflectivity and its manufacturing process.

[0022] like Figure 1As shown, the structure includes a grooved substrate 1 with orthogonally arranged dovetail-shaped grooves 11 on its surface. The dovetail-shaped grooves 11 are composed of a dovetail-shaped bottom surface 111 and a dovetail-shaped steep wall surface 112, with a dovetail-shaped cross-section. A high-reflectivity coating 2 is provided on the dovetail-shaped bottom surface 111 and the top surface 113 of the dovetail-shaped groove body, and micro / nano papillary radiation structures 3 are provided on the dovetail-shaped steep wall surface 112. Figure 2 and Figure 3 As shown, the micro / nanopapillary radiation structure 3 is a hierarchical structure, including a micron-sized core papillary 31, micron-sized multi-level papillary 32 clustered on the surface of the core papillary 31, and nano-sized particles densely distributed on the surface of the multi-level papillary 32.

[0023] The grooved substrate 1 is made of a smooth, cuboid titanium sheet that has been polished and processed by electrolytic wire cutting. The dovetail-shaped groove 11 has a long side width of 1~10 mm, a short side width of 0.5~5 mm, and a height of 1~10 mm. The bottom surface 111 of the dovetail-shaped groove is parallel to the horizontal direction, and the steep wall surface 112 of the dovetail-shaped groove makes an angle of 20~30° with the vertical direction.

[0024] The high-reflectivity coating 2 is a smooth and flat thin-film metal layer, which is deposited on the bottom surface 111 of the dovetail-shaped trench and the top surface 113 of the dovetail-shaped trench body by magnetron sputtering, electron beam evaporation or chemical / electrochemical coating process.

[0025] The micro / nano papillary radiation structure 3 was fabricated by scanning and ablation on the dovetail-shaped groove steep wall surface 112 after fixing the grooved substrate 1 at a 45° angle using a nanosecond pulsed laser. The grooved substrate 1 was then rotated 90° in an orthogonal direction, and the dovetail-shaped groove steep wall surface 112 in another orthogonal direction was scanned and ablated line by line. The processing parameters included a laser power of 4–7 W, a scanning speed of 40 mm / s, a filling spacing of 1 μm, and a repetition frequency of 40 kHz. In the micro / nano papillary radiation structure 3, the core papilla 31 has a diameter of 6–12 μm, the multi-level papilla 32 has a diameter of 2–4 μm and a height of 3–6 μm, and the particle size is 10–50 nm. The cross-section of the entire micro / nano papillary radiation structure 3 is bear paw-shaped.

[0026] like Figure 4 As shown, the high-reflectivity coating 2 is used to achieve high reflectivity in the 0.3~2.5 μm solar radiation band to reduce the absorption of solar energy; the micro / nano papillary radiation structure 3, based on the light-trapping effect and surface plasmon resonance principle, has high absorption / high emission characteristics in the 2~15 μm infrared band, and is used to emit heat into outer space through the atmospheric window in the form of infrared radiation. The two work synergistically to significantly improve the overall radiative cooling effect.

[0027] Example 2 This embodiment provides a high-temperature radiation cooling microgroove-micro-nanoplasty structure with high top projection reflectivity and its manufacturing process.

[0028] like Figure 5 As shown, the structure includes a grooved substrate 1 with dovetail-shaped grooves 11 arranged in a unidirectional comb-like array on its surface. The dovetail-shaped grooves 11 are composed of a dovetail-shaped groove bottom surface 111 and a dovetail-shaped groove steep wall surface 112, with a dovetail-shaped cross-section. A high-reflectivity coating 2 is provided on the dovetail-shaped groove bottom surface 111 and the top surface 113 of the dovetail-shaped groove body, and a micro / nano papillary radiation structure 3 is provided on the dovetail-shaped groove steep wall surface 112. The micro / nano papillary radiation structure 3 is a hierarchical structure, including a micron-sized core papillary 31, micron-sized multi-level papillary 32 clustered on the surface of the core papillary 31, and nano-sized particles densely distributed on the surface of the multi-level papillary 32.

[0029] The grooved substrate 1 is made of a smooth, cuboid titanium sheet that has been polished and processed by electrolytic wire cutting. The dovetail-shaped groove 11 has a long side width of 1~10 mm, a short side width of 0.5~5 mm, and a height of 1~10 mm. The bottom surface 111 of the dovetail-shaped groove is parallel to the horizontal direction, and the steep wall surface 112 of the dovetail-shaped groove makes an angle of 20~30° with the vertical direction.

[0030] The high-reflectivity coating 2 is a smooth and flat thin-film metal layer, which is deposited on the bottom surface 111 of the dovetail-shaped trench and the top surface 113 of the dovetail-shaped trench body by magnetron sputtering, electron beam evaporation or chemical / electrochemical coating process.

[0031] The micro / nano papillary radiation structure 3 was fabricated by scanning the dovetail-shaped groove steep wall surface 112 after fixing the grooved substrate 1 at a 45° angle using a nanosecond pulsed laser. The processing parameters included a laser power of 4–7 W, a scanning speed of 40 mm / s, a filling spacing of 1 μm, and a repetition frequency of 40 kHz. In the micro / nano papillary radiation structure 3, the diameter of the core papilla 31 is 6–12 μm, the diameter of the multi-level papilla 32 is 2–4 μm, the height is 3–6 μm, and the particle size is 10–50 nm. The cross-section of the entire micro / nano papillary radiation structure 3 is bear paw shaped.

[0032] Example 3 This embodiment provides a high-temperature radiation cooling microgroove-micro-nanoplasty structure with high top projection reflectivity and its manufacturing process.

[0033] like Figure 6As shown, the structure includes a trench-shaped substrate 1 with rectangular trenches 12 arranged in an orthogonal array on its surface. The rectangular trenches 12 are composed of a rectangular trench bottom surface 121 and a rectangular trench steep wall surface 122, with a rectangular cross-section. A high-reflectivity coating 2 is provided on the rectangular trench bottom surface 121 and the top surface 123 of the rectangular trench body, and a micro / nano papillary radiation structure 3 is provided on the rectangular trench steep wall surface 122. The micro / nano papillary radiation structure 3 is a hierarchical structure, including a micron-sized core papillary 31, micron-sized multi-level papillary 32 clustered on the surface of the core papillary 31, and nano-sized particles densely distributed on the surface of the multi-level papillary 32.

[0034] The grooved substrate 1 is made of a smooth rectangular titanium sheet that has been polished and processed by electrolytic wire cutting. The rectangular groove 12 is 1~10 mm wide and 1~10 mm high. The bottom surface 121 of the rectangular groove is parallel to the horizontal direction, and the steep wall surface 122 of the rectangular groove makes an angle of 90° with the horizontal direction.

[0035] The high-reflectivity coating 2 is a smooth and flat thin-film metal layer, which is deposited on the bottom surface 121 of the rectangular trench and the top surface 123 of the rectangular trench body by magnetron sputtering, electron beam evaporation or chemical / electrochemical coating process.

[0036] The micro / nano papillary radiation structure 3 was fabricated by scanning and ablation on a rectangular groove steep wall surface 122 after fixing the grooved substrate 1 at a 45° angle using a nanosecond pulsed laser. The grooved substrate 1 was then rotated 90° along an orthogonal direction, and the rectangular groove steep wall surface 122 in another orthogonal direction was scanned and ablated line by line. The processing parameters included a laser power of 4–7 W, a scanning speed of 40 mm / s, a filling spacing of 1 μm, and a repetition frequency of 40 kHz. In the micro / nano papillary radiation structure 3, the core papilla 31 has a diameter of 6–12 μm, the multi-level papilla 32 has a diameter of 2–4 μm and a height of 3–6 μm, and the particle size is 10–50 nm. The cross-section of the entire micro / nano papillary radiation structure 3 is bear paw shaped.

[0037] Example 4 This embodiment provides a high-temperature radiation cooling microgroove-micro-nanoplasty structure with high top projection reflectivity and its manufacturing process.

[0038] like Figure 7 As shown, the structure includes a trench-shaped substrate 1 with rectangular trenches 12 arranged in a unidirectional comb-like array on its surface. The rectangular trenches 12 are composed of a rectangular trench bottom surface 121 and a rectangular trench steep wall surface 122, with a rectangular cross-section. A high-reflectivity coating 2 is provided on the rectangular trench bottom surface 121 and the top surface 123 of the rectangular trench body, and a micro / nano papillary radiation structure 3 is provided on the rectangular trench steep wall surface 122. The micro / nano papillary radiation structure 3 is a hierarchical structure, including a micron-sized core papillary 31, micron-sized multi-level papillary 32 clustered on the surface of the core papillary 31, and nano-sized particles densely distributed on the surface of the multi-level papillary 32.

[0039] The grooved substrate 1 is made of a smooth rectangular titanium sheet that has been polished and processed by electrolytic wire cutting. The rectangular groove 12 is 1~10 mm wide and 1~10 mm high. The bottom surface 121 of the rectangular groove is parallel to the horizontal direction, and the steep wall surface 122 of the rectangular groove makes an angle of 90° with the horizontal direction.

[0040] The high-reflectivity coating 2 is a smooth and flat thin-film metal layer, which is deposited on the bottom surface 121 of the rectangular trench and the top surface 123 of the rectangular trench body by magnetron sputtering, electron beam evaporation or chemical / electrochemical coating process.

[0041] The micro / nano papillary radiation structure 3 was fabricated by scanning the grooved substrate 1 at a 45° angle onto the steep wall surface 122 of a rectangular groove using a nanosecond pulsed laser. The processing parameters included a laser power of 4–7 W, a scanning speed of 40 mm / s, a filling spacing of 1 μm, and a repetition frequency of 40 kHz. In the micro / nano papillary radiation structure 3, the core papilla 31 has a diameter of 6–12 μm, the multi-level papilla 32 has a diameter of 2–4 μm and a height of 3–6 μm, and the particle size is 10–50 nm. The cross-section of the entire micro / nano papillary radiation structure 3 is bear paw shaped.

[0042] Example 5 This embodiment provides a high-temperature radiation cooling microgroove-micro-nanoplasty structure with high top projection reflectivity and its manufacturing process.

[0043] like Figure 8 As shown, the structure includes a grooved substrate 1 with orthogonally arranged sawtooth grooves 13 on its surface. The sawtooth grooves 13 are composed of inclined surfaces 131 and steep walls 132, with a rectangular cross-section. A high-reflectivity coating 2 is provided on the inclined surfaces 131, and micro / nano papillary radiation structures 3 are provided on the steep walls 132. The micro / nano papillary radiation structures 3 are hierarchical structures, including a micron-sized core papillary 31, micron-sized multi-level papillary 32 clustered on the surface of the core papillary 31, and nano-sized particles densely distributed on the surface of the multi-level papillary 32. The portion 14 of the grooved substrate 1 without sawtooth grooves also has a high-reflectivity coating 2.

[0044] The grooved substrate 1 is made of a smooth, cuboid titanium sheet that has been polished and processed by electrolytic wire cutting. The serrated groove 13 is 1-10 mm wide and 1-10 mm high. The angle between the inclined surface 131 of the serrated groove and the horizontal direction is 10-60°. The angle between the steep wall surface 132 of the serrated groove and the horizontal direction is 90° or it deviates inward by no more than 20° from the inclined surface 131 of the serrated groove.

[0045] The high-reflectivity coating 2 is a smooth and flat thin-film metal layer, which is deposited on the inclined surface 131 of the serrated groove and the portion 14 of the grooved substrate 1 where the serrated groove is not provided by magnetron sputtering, electron beam evaporation or chemical / electrochemical coating process.

[0046] The micro / nano papillary radiation structure 3 was fabricated by scanning and ablation of the grooved substrate 1 (1) at a 45° angle using a nanosecond pulsed laser. The substrate 1 was then rotated 90° along an orthogonal direction, and the rectangular grooved steep wall 122 in another orthogonal direction was scanned and ablated line by line. The processing parameters included a laser power of 4–7 W, a scanning speed of 40 mm / s, a filling spacing of 1 μm, and a repetition frequency of 40 kHz. In the micro / nano papillary radiation structure 3, the core papilla 31 has a diameter of 6–12 μm, the multi-level papilla 32 has a diameter of 2–4 μm and a height of 3–6 μm, and the particle size is 10–50 nm. The cross-section of the entire micro / nano papillary radiation structure 3 is bear paw-shaped.

[0047] Example 6 This embodiment provides a high-temperature radiation cooling microgroove-micro-nanoplasty structure with high top projection reflectivity and its manufacturing process.

[0048] like Figure 9 As shown, the structure includes a grooved substrate 1 with serrated grooves 13 arranged in a unidirectional comb-like array on its surface. The serrated grooves 13 are composed of inclined surfaces 131 and steep walls 132, with a rectangular cross-section. A high-reflectivity coating 2 is provided on the inclined surfaces 131, and micro / nano papillary radiation structures 3 are provided on the steep walls 132. The micro / nano papillary radiation structures 3 are hierarchical structures, including a micron-sized core papillary 31, micron-sized multi-level papillary 32 clustered on the surface of the core papillary 31, and nano-sized particles densely distributed on the surface of the multi-level papillary 32. The portion 14 of the grooved substrate 1 without serrated grooves also has a high-reflectivity coating 2.

[0049] The grooved substrate 1 is made of a smooth, cuboid titanium sheet that has been polished and processed by electrolytic wire cutting. The serrated groove 13 is 1-10 mm wide and 1-10 mm high. The angle between the inclined surface 131 of the serrated groove and the horizontal direction is 10-60°. The angle between the steep wall surface 132 of the serrated groove and the horizontal direction is 90° or it deviates inward by no more than 20° from the inclined surface 131 of the serrated groove.

[0050] The high-reflectivity coating 2 is a smooth and flat thin-film metal layer, which is deposited on the inclined surface 131 of the serrated groove and the portion 14 of the grooved substrate 1 where the serrated groove is not provided by magnetron sputtering, electron beam evaporation or chemical / electrochemical coating process.

[0051] The micro / nano papillary radiation structure 3 was fabricated by scanning the serrated grooved steep wall surface 132 with a nanosecond pulsed laser after fixing the grooved substrate 1 at a 45° angle. The processing parameters included a laser power of 4–7 W, a scanning speed of 40 mm / s, a filling spacing of 1 μm, and a repetition frequency of 40 kHz. In the micro / nano papillary radiation structure 3, the diameter of the core papilla 31 is 6–12 μm, the diameter of the multi-level papilla 32 is 2–4 μm, the height is 3–6 μm, and the particle size is 10–50 nm. The cross-section of the entire micro / nano papillary radiation structure 3 is bear paw shaped.

[0052] In this invention, unless otherwise stated, scientific and technical terms used herein have the meanings commonly understood by those skilled in the art. Furthermore, the reagents, materials, and procedures used herein are all widely used in the relevant fields.

[0053] It should be noted that the terms such as "upper", "lower", "left", "right", "front", and "back" used in the invention are only for clarity of description and are not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0054] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-temperature radiation cooling microgroove-micro / nanoplasty structure with high top-projection reflectivity, characterized in that: Including trench-shaped substrates, high-reflectivity coatings, and micro / nano papillary radiation structures; The grooved substrate is a substrate with grooves on its surface; the grooves are arranged in a unidirectional comb-like array or an orthogonal array on the substrate surface; The top projected surface of the trench is provided with the high-reflectivity coating; The non-top projection surface of the trench is provided with the micro / nano papillary radiation structure; The micro / nanopapillary radiation structure includes a micrometer-scale core papilla, micrometer-scale multilevel papillae clustered on the surface of the core papilla, and nanometer-scale particles densely distributed on the surface of the multilevel papillae.

2. The high-temperature radiation cooling microgroove-micro / nanoplasty structure with high top projection reflectivity according to claim 1, characterized in that: The grooves in the grooved substrate are serrated, rectangular, or dovetail-shaped. The serrated groove is composed of a serrated groove inclined surface and a serrated groove steep wall surface; the high-reflectivity coating is provided on the serrated groove inclined surface, and the micro-nano papillary radiation structure is provided on the serrated groove steep wall surface. The rectangular trench is composed of a rectangular trench bottom surface and a rectangular trench steep wall surface; the high-reflectivity coating is provided on the rectangular trench bottom surface and the top surface of the rectangular trench body, and the micro-nano papillary radiation structure is provided on the rectangular trench steep wall surface; The dovetail-shaped groove is composed of a dovetail-shaped groove bottom surface and a dovetail-shaped groove steep wall surface; the dovetail-shaped groove bottom surface and the dovetail-shaped groove body top surface are provided with the high-reflectivity coating, and the dovetail-shaped groove steep wall surface is provided with the micro-nano papillary radiation structure.

3. The high-temperature radiation cooling microgroove-micro / nanoplasty structure with high top projection reflectivity according to claim 2, characterized in that: The serrated grooves are spaced 0.1 to 10 mm apart and have a height of 0.1 to 10 mm. The angle between the inclined surface of the serrated groove and the surface of the grooved base is 10 to 60°. The angle between the steep wall of the serrated groove and the surface of the grooved base is 90° or deviates no more than 20° inward from the inclined surface of the serrated groove. The rectangular grooves are spaced 0.1 to 10 mm apart and have a height of 0.1 to 10 mm. The bottom surface of the rectangular groove is coplanar or parallel to the surface of the grooved base. The angle between the steep wall of the rectangular groove and the surface of the grooved base is 90°. The dovetail grooves are spaced 0.1 to 10 mm apart and have a height of 0.1 to 10 mm. The bottom surface of the dovetail groove is coplanar or parallel to the surface of the grooved base. The angle between the steep wall of the dovetail groove and the surface of the grooved base is 60 to 70°.

4. The high-temperature radiation cooling microgroove-micro / nanoplasty structure with high top projection reflectivity according to claim 1, characterized in that: The high-reflectivity coating is also provided on the portion of the grooved substrate surface where no grooves are provided.

5. The high-temperature radiation cooling microgroove-micro / nanoplasty structure with high top projection reflectivity according to claim 1, characterized in that: The thickness of the high-reflectivity coating is 100 ~ 1000 nm.

6. The high-temperature radiation cooling microgroove-micro / nanoplasty structure with high top projection reflectivity according to claim 1, characterized in that: In the micro / nano papillary radiation structure, the diameter of the core papilla is 6-12 μm, the diameter of the multi-level papilla is 2-4 μm, the height is 3-6 μm, and the size of the particles is 10-50 nm.

7. The high-temperature radiation cooling microgroove-micro / nanoplasty structure with high top projection reflectivity according to claim 1, characterized in that: The materials of the grooved substrate, the high-reflectivity coating, and the micro / nano papillary radiation structure are all metals.

8. The high-temperature radiation cooling microgroove-micro / nanoplasty structure with high top projection reflectivity according to claim 7, characterized in that: The materials of the grooved substrate and the micro / nano papillary radiation structure are stainless steel, copper, titanium, or high-temperature alloys. The material of the high-reflectivity coating is gold, silver, or platinum; The grooved substrate and the micro / nanoplasty radiation structure are made of the same material.

9. The manufacturing process of the high-temperature radiation cooling microgroove-micro / nanopapular structure with high top projection reflectivity as described in any one of claims 1 to 8, characterized in that: Includes the following steps: S1: Grooves arranged in a unidirectional comb-like array or an orthogonal array are processed on the surface of the substrate using an electrolytic wire cutting process to form the grooved substrate; S2: Place the trench-shaped substrate obtained in S1 on a coating platform and process it by magnetron sputtering, electron beam evaporation or chemical / electrochemical coating process to obtain the high-reflectivity coating. S3: Tilt the grooved substrate with the high-reflectivity coating obtained in S2 so that the non-top projection surface is exposed to the processing area. Use nanosecond, picosecond, or femtosecond pulsed lasers to perform line-by-line scanning ablation on the non-top projection surface to obtain a micro-nano papillary radiation structure.

10. A radiation cooling device, characterized in that: It includes the high-temperature radiation cooling microgroove-micro-nanoplastic structure with high top projection reflectivity as described in any one of claims 1 to 8.

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