Preparation method of infrared high-emission metasurface

Abstract

The invention discloses a preparation method of an infrared high-emission metasurface, and relates to a preparation method of a high-emission metasurface. The invention aims to solve the technical problem that the high emissivity is difficult to maintain in the processing and using processes of the aluminum-based material at present. According to the method, the substrate is etched through laser, then the aluminum particles are prepared on the micro pits in an electro-deposition mode, multiple scattering of electromagnetic waves on the surfaces of the aluminum particles is achieved, and the emissivity of the material surface is improved. According to the method, the emissivity of the surface of the aluminum base is effectively improved, the average reflectivity within the wavelength range of 2.5-22.5 microns is as low as 0.1, and it is indicated that the average emissivity of the surface of the aluminum base can reach 0.9. According to the method, performance reduction in the machining and using process can be avoided, and continuous large-scale production can be achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to a preparation method of an infrared high-emission super surface. BACKGROUND

[0002] With the development of industrial technology, thermal control materials with high emissivity have broad application prospects in the fields of aerospace, electronics and semiconductors. For high-performance chips, spacecraft electronic components and other equipment that need to dissipate heat, high-emission surfaces can quickly dissipate the heat generated inside in the form of radiation, becoming one of the methods to regulate equipment heat and ensure stable operation of equipment. At present, coating technology is a widely used solution, and by coating a special functional coating on the surface of the substrate, the emissivity of the material surface can be effectively improved. However, the high-temperature resistance of some coating materials is insufficient, and the difference in thermal expansion coefficient between the coating and the substrate can easily cause the coating to peel off, which limits the application range of high-emission coatings. In order to avoid the above drawbacks of coating technology, a high-emission surface based on microstructure can be designed. Microstructure constructs specific geometric patterns on the material surface, and uses electromagnetic wave interference, scattering and absorption to regulate the emissivity of the material. Compared with coating, microstructure is directly prepared on the substrate surface and is not easy to fall off; at the same time, its performance is less affected by the chemical properties of the material, and has better stability and durability.

[0003] Aluminum is a commonly used material in the fields of aerospace and semiconductors, and has the advantages of small density, good thermal conductivity and excellent processing performance. In order to realize high emissivity of aluminum-based material surface, it can be theoretically made into nanorods with a certain aspect ratio. When electromagnetic waves irradiate the surface of the nanorod array, multiple reflections and scattering will occur between the nanorods, significantly lengthening the optical path and strengthening the absorption. According to the Kirchhoff's law of thermal radiation, this strong absorption characteristic can be converted into high emissivity, especially in the infrared waveband. However, in order to ensure that the surface of the aluminum-based nanorod maintains a certain emissivity, nanorods with a large aspect ratio need to be designed, which can easily cause problems such as lodging, breaking or size unevenness during processing and use, resulting in the decay of emission performance. The bottleneck in the preparation process seriously restricts its application prospect. SUMMARY

[0004] The present application is to solve the technical problem that it is difficult to maintain high emissivity during the processing and use of aluminum-based materials, and to provide a preparation method of an infrared high-emission super surface.

[0005] The preparation method of the infrared high-emission super surface of the present application is carried out according to the following steps:

[0006] I. Using a nanosecond laser to etch a micro-pit array on the surface of the substrate;

[0007] II. The substrate prepared in step I is used as a working electrode, an Al piece is used as a counter electrode, and HgO / Hg is used as a reference electrode, and an aluminum particle is prepared by using an electrodeposition method.

[0008] Compared with the prior art, the present application has the following advantages:

[0009] 1. The present application first uses laser etching on the substrate, and then uses an electrodeposition method to prepare aluminum particles on the micro-pits, so that the electromagnetic waves are scattered multiple times on the surface of the aluminum particles, and the emissivity of the material surface is improved.

[0010] 2. The present application effectively improves the emissivity of the aluminum-based surface, and the average reflectivity in the wavelength range of 2.5 μm~22.5 μm is as low as 0.1, which indicates that the average emissivity of the aluminum-based surface can reach 0.9.

[0011] 3. The method of the present application can avoid performance degradation during processing and use, and can realize continuous large-scale production. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 SEM image of the aluminum particles deposited in test one;

[0013] Figure 2 SEM image of the aluminum particles deposited in test two;

[0014] Figure 3 SEM image of the aluminum particles deposited in test three;

[0015] Figure 4 SEM image of the aluminum particles deposited in test four;

[0016] Figure 5 SEM image of the aluminum particles deposited in test five;

[0017] Figure 6 SEM image of the aluminum particles deposited in test six;

[0018] Figure 7 SEM image of the aluminum particles deposited in test seven;

[0019] Figure 8 SEM image of the aluminum particles deposited in test eight

[0020] Figure 9 SEM image of the aluminum particles deposited in test nine;

[0021] Figure 10 Reflectivity test result graph of the surface of the aluminum particles obtained without laser etching under the corresponding electrodeposition conditions in test one, test four, test seven, and the like;

[0022] Figure 11Figure for reflectivity test result of surface of aluminum particles obtained without laser etching under test two, test five, test eight and corresponding electrodeposition conditions;

[0023] Figure 12 Figure for reflectivity test result of surface of aluminum particles obtained without laser etching under test three, test six, test nine and corresponding electrodeposition conditions. DETAILED DESCRIPTION

[0024] Embodiment one: the embodiment is a preparation method of infrared high-emission super surface, which is specifically performed according to the following steps:

[0025] I. etching micro-pit array on surface of substrate by nanosecond laser;

[0026] II. using electrodeposition method to prepare aluminum particles by taking the substrate prepared in step I as working electrode, Al sheet as counter electrode and HgO / Hg as reference electrode.

[0027] Embodiment two: the embodiment is different from embodiment one in that the substrate in step I is indium steel. The other steps are the same as those in embodiment one.

[0028] Embodiment three: the embodiment is different from embodiment two in that the power of laser in step I is 30 W. The other steps are the same as those in embodiment two.

[0029] Embodiment four: the embodiment is different from embodiment three in that the frequency of laser in step I is 100 Hz. The other steps are the same as those in embodiment three.

[0030] Embodiment five: the embodiment is different from embodiment four in that the scanning speed of laser in step I is 10 μm / s. The other steps are the same as those in embodiment four.

[0031] Embodiment six: the embodiment is different from embodiment five in that the line spacing of laser in step I is 30-80 μm. The other steps are the same as those in embodiment five.

[0032] Embodiment seven: the embodiment is different from embodiment six in that the pulse width of laser in step I is 500 ns. The other steps are the same as those in embodiment six.

[0033] Embodiment eight: the embodiment is different from embodiment seven in that the deposition solution used in electrodeposition method in step II is AlCl3 aqueous solution. The other steps are the same as those in embodiment seven.

[0034] Specific embodiment nine: the difference between this embodiment and specific embodiment eight is that the concentration of the AlCl3 aqueous solution in step two is 200 mmol / L. The rest is the same as specific embodiment eight.

[0035] Specific embodiment ten: the difference between this embodiment and specific embodiment nine is that the electrodeposition method in step two is carried out in a constant potential mode, the deposition potential is 2.5V~10V, and the deposition time is 30s. The rest is the same as specific embodiment nine.

[0036] The present application is verified by the following tests:

[0037] Test one: this test is a preparation method of an infrared high-emission super surface, which is carried out according to the following steps:

[0038] I. etching a micro-pit array on the surface of an indium steel substrate with a nanosecond laser; the working parameters of the laser are: power is 30W, frequency is 100Hz, scanning speed is 10μm / s, line spacing is 30μm, and pulse width is 500ns;

[0039] II. using the indium steel substrate prepared in step I as a working electrode, an Al piece as a counter electrode, HgO / Hg as a reference electrode, and an electrodeposition method to prepare aluminum particles;

[0040] The deposition solution used in the electrodeposition method is an AlCl3 aqueous solution with a concentration of 200mmol / L;

[0041] The electrodeposition method is carried out in a constant potential mode, the deposition potential is 10V, and the deposition time is 30s.

[0042] Figure 1 The SEM image of the aluminum particles deposited in test one is shown in the following figure: Figure 1 It can be seen that the aluminum particles can be deposited on the etched indium steel substrate, but the particles are not completely separated and the final prepared nanoparticles have a particle size of 30μm.

[0043] Comparative test one: this test is a non-etching + electrodeposition, the difference between the specific process and test one is that there is no step I, and the unetched indium steel substrate is directly used as a working electrode, an Al piece is used as a counter electrode, HgO / Hg is used as a reference electrode, and an electrodeposition method is used to prepare aluminum particles. The rest is the same as test one.

[0044] Figure 10 The reflectivity test result is shown in the following figure, the dark blue is the product of test one, and the yellow is the product of comparative test one. As can be seen from the figure, the reflectivity of the aluminum particles deposited on the etched indium steel substrate is reduced by 50% compared with the unetched surface, which indicates that the emissivity of the aluminum-based surface is improved.

[0045] Test two: The difference between this test and test one is that the line spacing of the laser in step one is 50 μm. The others are the same as test one.

[0046] Figure 2 The SEM image of the aluminum particles obtained by test two is shown in FIG. 4, from which it can be seen that the aluminum particles can be deposited on the surface of the etched indium steel substrate, and the particle dispersion is good. The particle size of the finally prepared nanoparticles is 50 μm. Figure 2

[0047] Comparative test two: This test is unetched + electrodeposition. The difference between the specific process of this test and test two is that there is no step one. The unetched indium steel substrate is directly used as the working electrode, the Al piece is used as the counter electrode, the HgO / Hg is used as the reference electrode, and the aluminum particles are prepared by electrodeposition. The others are the same as test two.

[0048] Figure 11 The reflectivity test result is shown in FIG. 6. The dark blue is the product of test two, and the yellow is the product of comparative test two. It can be seen from the figure that the reflectivity of the aluminum particles deposited on the surface of the etched indium steel substrate is reduced by 40% compared with the unetched surface, indicating that the emissivity of the aluminum-based surface is improved.

[0049] Test three: The difference between this test and test one is that the line spacing of the laser in step one is 80 μm. The others are the same as test one.

[0050] Figure 3 The SEM image of the aluminum particles obtained by test three is shown in FIG. 8, from which it can be seen that the aluminum particles can be deposited on the surface of the etched indium steel substrate, and the particle dispersion is good. The particle size of the finally prepared nanoparticles is 80 μm. Figure 3

[0051] Comparative test three: This test is unetched + electrodeposition. The difference between the specific process of this test and test three is that there is no step one. The unetched indium steel substrate is directly used as the working electrode, the Al piece is used as the counter electrode, the HgO / Hg is used as the reference electrode, and the aluminum particles are prepared by electrodeposition. The others are the same as test three.

[0052] Figure 12 The reflectivity test result is shown in FIG. 10. The dark blue is the product of test three, and the yellow is the product of comparative test three. It can be seen from the figure that the reflectivity of the aluminum particles deposited on the surface of the etched indium steel substrate is reduced by 40% compared with the unetched surface, indicating that the emissivity of the aluminum-based surface is improved.

[0053] Test four: The difference between this test and test one is that the deposition potential in step two is 5 V. The others are the same as test one.

[0054] Figure 4 The SEM image of the aluminum particles obtained by test four is shown in FIG. 12, from which it can be seen that the aluminum particles can be deposited on the surface of the etched indium steel substrate, and the particle dispersion is good. The particle size of the finally prepared nanoparticles is 50 μm. Figure 4 ​​It can be seen that the aluminum particles can be deposited on the surface of the etched indium steel substrate, and the particles are partially adhered. The particle size of the finally prepared nanoparticles is 30 μm.

[0055] Comparative Test Four: This test is non-etching + electrodeposition. The difference between the specific process and Test Four is that there is no step one. The unetched indium steel substrate is directly used as the working electrode, the Al piece is used as the counter electrode, the HgO / Hg is used as the reference electrode, and the aluminum particles are prepared by electrodeposition. The others are the same as Test Four.

[0056] Figure 10 The figure is the reflectivity test result. The green color is the product of Test Four, and the pink color is the product of Comparative Test Four. It can be seen from the figure that the reflectivity of the aluminum particles deposited on the surface of the etched indium steel substrate is reduced by 60% compared with the unetched surface, indicating that the emissivity of the aluminum-based surface is improved.

[0057] Test Five: The difference between this test and Test Two is that the deposition potential in step two is 5V. The others are the same as Test Two.

[0058] Figure 5 The figure is the SEM image of the aluminum particles deposited in Test Five. It can be seen from the figure that the aluminum particles can be deposited on the surface of the etched indium steel substrate, and the particle size of the finally prepared nanoparticles is 50 μm. Figure 5

[0059] Comparative Test Five: This test is non-etching + electrodeposition. The difference between the specific process and Test Five is that there is no step one. The unetched indium steel substrate is directly used as the working electrode, the Al piece is used as the counter electrode, the HgO / Hg is used as the reference electrode, and the aluminum particles are prepared by electrodeposition. The others are the same as Test Five.

[0060] Figure 11 The figure is the reflectivity test result. The green color is the product of Test Five, and the pink color is the product of Comparative Test Five. It can be seen from the figure that the reflectivity of the aluminum particles deposited on the surface of the etched indium steel substrate is reduced by 60% compared with the unetched surface, indicating that the emissivity of the aluminum-based surface is improved.

[0061] Test Six: The difference between this test and Test Three is that the deposition potential in step two is 5V. The others are the same as Test Three.

[0062] Figure 6 The figure is the SEM image of the aluminum particles deposited in Test Six. It can be seen from the figure that the aluminum particles can be deposited on the surface of the etched indium steel substrate, and the particle size of the finally prepared nanoparticles is 80 μm. Figure 6

[0063] ​​Comparative Test Six: This test is non-etched + electrodeposition, the specific process is different from Test Six, which is: without step one, directly use non-etched indium steel substrate as working electrode, Al piece as counter electrode, HgO / Hg as reference electrode, and prepare aluminum particles by electrodeposition method. The others are the same as Test Six.

[0064] Figure 12 The figure is the reflectivity test result, green is the product of Test Six, and pink is the product of comparative Test Six. As can be seen from the figure, the reflectivity of aluminum particles deposited on the surface of etched indium steel substrate is reduced by 80% compared with the surface without etching, indicating that the emissivity of aluminum-based surface is improved.

[0065] Test Seven: This test is different from Test One in that the deposition potential in step two is 2.5V. The others are the same as Test One.

[0066] Figure 7 The figure is the SEM of aluminum particles deposited by Test Seven. As can be seen from the figure, Figure 7 aluminum particles can be deposited on the surface of etched indium steel substrate, and the particles are partially adhered. The final prepared nanoparticles have a particle size of 30μm.

[0067] Figure 10 The figure is the reflectivity test result, red is the product of Test Seven, and light blue is the product of comparative Test Seven. As can be seen from the figure, Figure 10 the reflectivity of aluminum particles deposited on the surface of etched indium steel substrate is reduced by 60% compared with the surface without etching, indicating that the emissivity of aluminum-based surface is improved.

[0068] Test Eight: This test is different from Test Two in that the deposition potential in step two is 2.5V. The others are the same as Test Two.

[0069] Figure 8 The figure is the SEM of aluminum particles deposited by Test Eight. As can be seen from the figure, aluminum particles can be deposited on the surface of etched indium steel substrate, and the particles are well dispersed. The final prepared nanoparticles have a particle size of 50μm.

[0070] Comparative Test Eight: This test is non-etched + electrodeposition, the specific process is different from Test Eight, which is: without step one, directly use non-etched indium steel substrate as working electrode, Al piece as counter electrode, HgO / Hg as reference electrode, and prepare aluminum particles by electrodeposition method. The others are the same as Test Eight.

[0071] Figure 11 The figure is the reflectivity test result, red is the product of Test Eight, and light blue is the product of comparative Test Eight. As can be seen from the figure, Figure 11 the reflectivity of aluminum particles deposited on the surface of etched indium steel substrate is reduced by 50% compared with the surface without etching, indicating that the emissivity of aluminum-based surface is improved.

[0072] Experiment Nine: This experiment differs from Experiment Three in that the deposition potential in step two is 2.5V. Everything else is the same as Experiment Three.

[0073] Figure 9 The image shows a SEM image of the aluminum particles obtained from the deposition in Experiment 9. Figure 9 It can be seen that aluminum particles can be deposited on the surface of the etched indium steel substrate, and the particle dispersion is good. The final nanoparticle size is 80μm.

[0074] Comparative Experiment Nine: This experiment involved unetched material followed by electrodeposition. The specific process differed from Experiment Nine in that step one was omitted. An unetched indium steel substrate was used directly as the working electrode, an Al sheet as the counter electrode, and HgO / Hg as the reference electrode. Aluminum particles were prepared using electrodeposition. All other aspects were the same as in Experiment Nine.

[0075] Figure 12 The graph shows the reflectance test results. Red represents the product of Experiment Nine, and light blue represents the product of the control Experiment Nine. Figure 12 It can be seen that the reflectivity of aluminum particles deposited on the etched indium steel substrate surface is reduced by 80% compared with the unetched surface, indicating that the emissivity of the aluminum substrate surface is improved.

Claims

1. A method for preparing an infrared hyper-emissive metasurface, characterized in that The method is carried out according to the following steps: I. etching micro-pit array on the surface of the substrate by using nanosecond laser; II. preparing aluminum particles by using electrodeposition method with the substrate prepared in step I as working electrode, Al piece as counter electrode and HgO / Hg as reference electrode.

2. The method of claim 1, wherein The substrate in step I is indium steel.

3. The method of claim 1, wherein The power of the laser in step I is 30 W.

4. The method of claim 3, wherein The frequency of the laser in step I is 100 Hz.

5. The method of claim 4, wherein The scanning speed of the laser in step I is 10 μm / s.

6. The method of claim 5, wherein The line spacing of the laser in step I is 30-80 μm.

7. The method of claim 6, wherein The pulse width of the laser in step I is 500 ns.

8. The method of claim 1, wherein The deposition solution used in the electrodeposition method in step II is AlCl3 aqueous solution.

9. The method of claim 8, wherein The concentration of the AlCl3 aqueous solution in step II is 200 mmol / L.

10. The method of claim 9, wherein The electrodeposition method in step II is carried out by using constant potential mode, the deposition potential is 2.5 V-10 V and the deposition time is 30 s.

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