Ultrafast laser processing close-packed concentric hexagonal array type solar evaporator and preparation method thereof

Abstract

The invention discloses an ultrafast laser processing close-packed concentric hexagonal array type solar evaporator and a preparation method thereof, and belongs to the technical field of solar evaporators. The front surface of the substrate is processed by using ultrafast laser to obtain a densely-arranged concentric hexagonal array type microstructure surface, and the densely-arranged concentric hexagonal array type microstructure surface is of an array structure formed by closely arranging a plurality of concentric hexagonal structure units. Each concentric hexagonal structure unit is formed by nesting multiple stages of hexagonal grooves with the same center and the spacing of about 30 microns, six edges of the outermost side of each concentric hexagonal structure unit are respectively overlapped with six edges of the outermost side of one concentric hexagonal structure unit in a bordering manner, and the rest can be done in the same manner. The densely-arranged concentric hexagonal array type microstructure surface is obtained through ultrafast laser processing, the absorbance, wettability, surface area and the like of the metal surface are improved, the surface evaporation performance can be improved, and the problems that an existing solar evaporator is complex in preparation process, low in evaporation efficiency and the like can be solved.

Description

Technical Field

[0001] The invention relates to the field of solar evaporation and water collection, and in particular to an ultrafast laser processed close-packed concentric hexagonal array type solar evaporator and a preparation method thereof. Background Art

[0002] With the frequent occurrence of extreme climates around the world and the continued shortage of fresh water resources on Earth, the demand for simple, stable and reliable fresh water resource acquisition devices continues to increase. Solar water evaporators are key devices that can convert sunlight into thermal energy and are used in applications such as seawater desalination and sewage treatment.

[0003] However, the preparation methods of traditional solar water evaporators have many limitations, such as low production efficiency and long preparation cycle. Therefore, a new preparation method is urgently needed to overcome these challenges.

[0004] Based on the above problems existing in the solar evaporator, the present invention designs a close-packed concentric hexagonal array solar evaporator based on ultrafast laser processing with simple process and high evaporation efficiency and a preparation method thereof. Summary of the invention

[0005] The present invention provides a close-packed concentric hexagonal array solar evaporator based on ultrafast laser processing and a preparation method thereof. A close-packed concentric hexagonal array microstructure surface is obtained by using ultrafast laser processing on a copper substrate, so that the surface properties such as absorbance, wettability, surface area and capillary action are improved, which is beneficial to improving the evaporation efficiency of the surface and can solve the problems of complex preparation process and poor durability of the existing solar evaporator.

[0006] In order to achieve the above-mentioned purpose, the present invention provides a close-packed concentric hexagonal array microstructure surface, which is prepared by ultrafast laser processing technology.

[0007] An ultrafast laser processed close-packed concentric hexagonal array solar evaporator is characterized in that the front side of a substrate is processed by ultrafast laser to obtain a close-packed concentric hexagonal array microstructure surface.

[0008] The densely packed concentric hexagonal array microstructure is a close-packed array structure, which is composed of many concentric hexagonal structural units closely arranged in an array structure, each concentric hexagonal structural unit is composed of nested multi-level hexagonal line grooves with the same center and a spacing of about 30um, and the outermost six sides of each concentric hexagonal structural unit are respectively bordered and overlapped with the outermost six sides of a concentric hexagonal structural unit, and so on; the inside and around the grooves are covered with a large number of microparticles due to the use of ultrafast laser processing. By adjusting the ultrafast laser processing parameters, a suitable groove processing depth is obtained.

[0009] The groove width is about 30-50um. When the multi-level hexagonal line grooves are nested, the spacing between two adjacent hexagons is 30, and the groove depth is 3-5um. Each unit is nested with 5-10 levels of hexagons, that is, there are 5-10 hexagons with different side lengths nested.

[0010] The back of the substrate is provided with a foam floating material, and the foam floating material is polystyrene foam.

[0011] The substrate is a polycrystalline copper substrate;

[0012] The center of each concentric hexagonal structural unit is a solid protrusion.

[0013] The ultrafast laser processor is a picosecond laser processor, which comprises a translation stage that can be used for sample positioning.

[0014] The above-mentioned method for preparing a close-packed concentric hexagonal array solar evaporator by ultrafast laser processing is characterized by comprising the following steps:

[0015] First, the substrate is placed in a container containing pickling liquid, and the container is placed in an ultrasonic cleaner for cleaning; then the substrate is taken out and left to dry;

[0016] Then, use sandpaper to grind the substrate to ensure that the oxide layer is completely removed and the connection surface is level, and then polish and dry it;

[0017] Afterwards, the laser control system is started, and the parameters of the ultrafast laser processing equipment are adjusted to prepare for processing the close-packed concentric hexagonal array microstructure;

[0018] Subsequently, the pre-processed substrate is placed within the irradiation range of the laser beam, and the position of the translation stage is adjusted to ensure that the substrate is within the laser processing area; then the ultrafast laser processing equipment is controlled to process the substrate surface according to the target pattern, adjusting the laser processing power and other parameters;

[0019] Finally, polystyrene foam is pasted on the back of the processed substrate to form a floating evaporation device.

[0020] Preferably, the pickling solution is H2SO4 solution.

[0021] When the ultrafast laser processed close-packed concentric hexagonal array solar evaporator is in use, the polystyrene foam faces downward, and the front surface with the close-packed concentric hexagonal array microstructure faces upward, floating in the water, while the front surface with the close-packed concentric hexagonal array microstructure is under the water surface, so that there is a layer of water on the front surface with the close-packed concentric hexagonal array microstructure.

[0022] The advantage of the present invention is that a close-packed concentric hexagonal array microstructure surface is obtained by using ultrafast laser processing, which improves the absorbance, wettability, surface area, etc. of the metal surface, is beneficial to improving the surface evaporation performance, and can solve the problems of complex preparation process and low evaporation efficiency of existing solar evaporators. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of this patent. For ordinary technicians in this field, other drawings can be obtained based on the following drawings without creative work.

[0024] Figure 1 Surface structure schematic diagram and microstructure diagram of laser processed close-packed concentric hexagonal array microstructure surface;

[0025] Figure 2 This is a complete processing flow chart;

[0026] Figure 3 is a reference diagram of evaporation efficiency of Example 1;

[0027] Figure 4 Schematic diagram of the surface structure of the copper substrate processed by ultrafast laser in Comparative Example 2;

[0028] Figure 5 The evaporation efficiency of comparative example 1, the optimal sample in embodiment 1 and comparative example 2 is compared. DETAILED DESCRIPTION

[0029] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. The present invention will be described in detail below with reference to the drawings and in combination with the embodiments.

[0030] The present invention will be further described below in conjunction with examples, but the present invention is not limited to the following examples.

[0031] Example 1: The following specifically describes the implementation method of the patent

[0032] 1. Preparation of copper substrate: Use wire cutting to make a square copper substrate with a size of 40mm×40mm×1mm;

[0033] 2. Preparation of polystyrene: Use a cutter to cut polystyrene foam into the size of 40mm×40mm×1mm;

[0034] 3. Soak the copper sheet with a purity greater than 99.99wt% and a size of 40mm×40mm×1mm in the prepared 30% H2SO4 aqueous solution for a few minutes to remove the oxides and pollutants on the surface of the copper substrate. After cleaning and drying, use sandpaper to polish to ensure that the oxide layer is completely removed and the surface is flat, then polish it for later use;

[0035] 4. Place the pre-processed substrate on the ultrafast laser processing table, use the laser rangefinder to level and focus, and then place it at the processing position. Adjust the laser parameters as follows: scanning power 10~50w, scanning speed 15mm / s, scanning once, scanning frequency 400kHz, pulse width 0.05ms, as shown below Figure 1 The graphics shown were processed with a spacing of 30 μm;

[0036] 5. Paste polystyrene foam on the back of the processed copper substrate to form a solar evaporator;

[0037] 6. Conduct a standard evaporation performance test under sunlight on the manufactured solar evaporator.

[0038] Comparative Example 1: The following specifically describes the implementation method of the patent

[0039] The method is basically the same as that in Example 1 except that the ultrafast laser processing is not performed and the cleaned, ground and polished copper sheet is directly used as the substrate for the evaporator.

[0040] The evaporation performance of the manufactured evaporator was tested.

[0041] Comparative Example 2: The following specifically describes the implementation method of the patent

[0042] Except for the ultrafast laser processing parameters in step 4, the rest is basically the same as in Example 1.

[0043] The ultrafast laser processing of this comparative example was adjusted as follows: scanning power 30W, scanning speed 15mm / s, scanning once (obtaining a line shape, not a grid), scanning frequency 400kHz, pulse width 0.05ms, as shown in Figure 4 The adjacent lines shown are processed with a spacing of 100um;

[0044] The evaporation performance of the manufactured evaporator was tested.

[0045] The implementation steps of the present invention are described in detail above in conjunction with the accompanying drawings. This embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation method and a specific operation process are given. However, the protection scope of the present invention is not limited to the following embodiments. Those skilled in the art can modify and polish it without changing the spirit and content of the present invention.

Claims

1. An ultrafast laser processed close-packed concentric hexagonal array solar evaporator, characterized in that: The front side of the substrate is processed by ultrafast laser to obtain a close-packed concentric hexagonal array microstructure surface. The close-packed concentric hexagonal array microstructure is a close-packed array structure, which is composed of many concentric hexagonal structural units tightly arranged. Each concentric hexagonal structural unit is composed of a nested multi-level hexagonal line groove with the same center and a spacing of about 30um. The outermost six sides of each concentric hexagonal structural unit are respectively bordered and overlapped with the outermost six sides of a concentric hexagonal structural unit, and so on. The inside and around the groove are covered with a large number of microparticles due to ultrafast laser processing. The groove width is about 30-50um, and the spacing between two adjacent hexagons when the multi-level hexagonal line grooves are nested is 30, and the groove depth is 3-5um. Each unit nests 5-10 levels of hexagons, that is, there are 5-10 nested hexagons with different side lengths.

2. An ultrafast laser processed close-packed concentric hexagonal array solar evaporator according to claim 1, characterized in that: The back of the substrate is provided with a foam floating material, and the foam floating material is polystyrene foam.

3. The ultrafast laser processed close-packed concentric hexagonal array solar evaporator according to claim 1, characterized in that: The substrate is a polycrystalline copper substrate.

4. The ultrafast laser processed close-packed concentric hexagonal array solar evaporator according to claim 1, characterized in that: The ultrafast laser processor is a picosecond laser processor, which comprises a translation stage that can be used for sample positioning.

5. A method for preparing a close-packed concentric hexagonal array solar evaporator by ultrafast laser processing according to any one of claims 1 to 4, characterized in that: The following steps are involved: First, the substrate is placed in a container containing pickling liquid, and the container is placed in an ultrasonic cleaner for cleaning; then the substrate is taken out and left to dry; Then, use sandpaper to grind the substrate to ensure that the oxide layer is completely removed and the connection surface is level, and then polish and dry it; Afterwards, the laser control system is started, and the parameters of the ultrafast laser processing equipment are adjusted to prepare for processing the close-packed concentric hexagonal array microstructure; Subsequently, the pre-processed substrate is placed within the irradiation range of the laser beam, and the position of the translation stage is adjusted to ensure that the substrate is within the laser processing area; then the ultrafast laser processing equipment is controlled to process the substrate surface according to the target pattern, adjusting the laser processing power and other parameters; Finally, polystyrene foam is pasted on the back of the processed substrate to form a floating evaporation device.

6. A method for preparing a close-packed concentric hexagonal array solar evaporator by ultrafast laser processing according to claim 5, characterized in that: The pickling solution is H2SO4 solution.

7. The method for preparing a close-packed concentric hexagonal array solar evaporator by ultrafast laser processing according to claim 5, characterized in that: The parameters of the laser were adjusted as follows: scanning power 10-50 W, scanning speed 15 mm / s, scanning once, scanning frequency 400 kHz, and pulse width 0.05 ms.

8. Application of an ultrafast laser processed close-packed concentric hexagonal array solar evaporator as described in any one of claims 1-4. When the ultrafast laser processed close-packed concentric hexagonal array solar evaporator is in use, the polystyrene foam faces downward, and the front surface with the close-packed concentric hexagonal array microstructure faces upward, floating in the water, and at the same time, the front surface with the close-packed concentric hexagonal array microstructure is under the water surface, so that there is a layer of water on the front surface with the close-packed concentric hexagonal array microstructure.

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