Method for preparing capillary core structure through unidirectional pulse electrodeposition and capillary core structure

Abstract

The invention belongs to the technical field of phase change heat transfer, and particularly relates to a method for preparing a capillary core structure through one-way pulse electrodeposition and the capillary core structure.The method comprises the following steps that after a to-be-deposited copper substrate is polished and cleaned, the copper substrate serves as a cathode, a copper plate serves as an anode, and pulse current electrodeposition is conducted in electrolyte containing sulfuric acid and copper sulfate; and sintering the deposited copper substrate in a reducing atmosphere to obtain the capillary core structure. Compared with a traditional hydrogen bubble template electrodeposition capillary core, the prepared electrodeposition capillary core has the smaller dendritic crystal length and the more complete porous surface, so that the mechanical strength of the capillary core is improved, and the service life of the capillary core is prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of phase change heat transfer, and particularly relates to a method for preparing a capillary wick structure by unidirectional pulse electrodeposition and the capillary wick structure. Background Art

[0002] As electronic devices develop towards high integration and high heat flux density, electronic systems have increasingly higher requirements for heat dissipation capabilities. Taking high-power semiconductor lasers as an example, their heat flux density is usually around 100 W / cm 2 This high heat flux density places extremely stringent demands on the heat dissipation capabilities of electronic systems. However, traditional air and water cooling methods struggle to meet the cooling requirements of high-power semiconductor lasers. Therefore, developing an efficient and reliable heat dissipation technology is crucial to solving this heat dissipation problem for electronic devices.

[0003] As an efficient heat transfer element, heat pipe is an advanced electronic cooling technology. The working principle of heat pipe is to transfer heat through the phase change circulation of liquid in the cavity. Due to its high efficiency, low thermal resistance and flexible structure, it has gradually become a key technology for solving the heat dissipation problem of high-power devices. The operation of heat pipe depends on the phase change cycle of the internal working fluid. The capillary wick, as the core component of the heat pipe, drives the working fluid to circulate between the evaporation section and the condensation section through capillary force, thereby achieving efficient heat transfer and directly affecting the heat transfer performance of the heat pipe. At present, improving the heat transfer efficiency of heat pipes is mainly achieved by controlling the microstructure size, heat transfer area and surface wettability of the capillary wick.

[0004] Currently, common capillary wick manufacturing methods include copper powder sintering, wire mesh sintering, and electrodeposition. The copper powder sintering method involves pressing copper powder into a shape and then sintering it at high temperature to form a porous structure. While the process is simple, it suffers from low porosity, limited specific surface area, and poor heat transfer performance. The wire mesh sintering method involves stacking multiple layers of metal wire mesh and then sintering them at high temperature to form a porous structure. The capillary wicks produced by this method have high porosity, but poor structural uniformity, a complex process, and high costs. The electrodeposition method involves electrodepositing metal in an electrolyte to form a porous structure. This method can produce capillary wick structures with high porosity, large specific surface area, and high heat transfer performance, and has therefore attracted considerable attention. Among these electrodeposition methods, hydrogen bubble template electrodeposition technology is a type of electrodeposition method. By generating hydrogen bubbles during the electrolysis process as a template, a porous structure can be formed on a copper substrate. This allows the production of porous capillary wicks with large surface area, high capillary performance, and high heat transfer efficiency. However, the structure has the problem that the micropore diameter is difficult to control, and the excessively long dendrites during the electrodeposition process can easily cause the structure to collapse. Summary of the Invention

[0005] In order to solve the problem that the porous copper structure prepared by the traditional hydrogen bubble template method has a large pore size and long dendrites, which leads to easy collapse during sintering, the present invention provides a method for preparing a capillary wick structure by unidirectional pulse electrodeposition and a capillary wick structure. By controlling the frequency and duty cycle of the pulse current, the present invention can effectively reduce the micropore diameter and dendrite length, reduce the risk of easy collapse during sintering due to long dendrites, and improve the structural integrity of the capillary wick.

[0006] The present invention is specifically implemented through the following technical solutions.

[0007] The present invention provides a method for preparing a capillary wick structure by unidirectional pulse electrodeposition, comprising the following steps: The copper substrate to be deposited is polished and cleaned to remove the oxide film and oil stains on the surface of the copper substrate. Then, the copper substrate is used as the cathode and the copper plate as the anode. Unidirectional pulse current electrodeposition is carried out in an electrolyte containing sulfuric acid and copper sulfate. The micropore diameter and dendrite length are reduced by controlling the pulse frequency and duty cycle.

[0008] The deposited copper substrate is sintered in a reducing atmosphere to obtain a capillary wick structure.

[0009] The present invention can prepare porous structure liquid-absorbing cores with different shapes and sizes on the sample surface through the above-mentioned production process, and the uniformity is better than that of the non-pulse electrodeposition method.

[0010] Preferably, during unidirectional pulse current electrodeposition, the current density is 0.05 A / cm 2 ~3 A / cm 2 , frequency is 0.03Hz~10 Hz, duty cycle is 10~99%, total time is 30s~7200s. More preferably, current density is 0.6A / cm 2 ~1.2A / cm 2 , frequency is 0.05Hz~0.5Hz, and duty cycle is 10%~99%.

[0011] Preferably, in the electrolyte, the concentration of hydrogen ions is in the range of 0.5 mol / L to 4 mol / L, the concentration of copper ions is in the range of 0.1 mol / L to 0.8 mol / L, and the solvent is water.

[0012] Preferably, the sintering temperature is 680° C. to 840° C., and the sintering time is 10 min to 120 min.

[0013] Preferably, the copper substrate material to be deposited is red copper or pure copper.

[0014] The present invention also provides a capillary wick structure prepared by the above-mentioned preparation method. The capillary wick structure is a honeycomb pore structure with dendrites growing on the pore walls, and the pore diameter is 40μm~300μm, and the branch length of the dendrite is 0.1μm~15μm. Under the same electrolyte concentration, current density, duty cycle and total time, the honeycomb pore diameter of the capillary wick and the length of the dendrite branches on the pore wall decrease as the pulse frequency increases. By controlling the pulse frequency and duty cycle, the diameter of the micropores on the surface of the copper electrodeposited by the hydrogen bubble template method can be regulated, which can effectively reduce the micropore diameter and dendrite length, reduce the risk of collapse during sintering due to long dendrites, and improve the structural integrity of the capillary wick.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention adopts an electrodeposition method to prepare a capillary wick. Copper ions in an electrolyte are deposited on a sample surface under the action of an electric potential field to form copper dendrites. Compared with traditional electrodeposition methods, the present invention adopts unidirectional pulse electrodeposition, which does not require changing the electrolyte composition and electrolyte temperature. By controlling the pulse frequency and duty cycle, the copper dendrite length is adjusted, and the micropore diameter is regulated. The prepared dendrite length is shorter, the dendrite has stronger anti-collapse ability, and the porous structure is more complete, which is conducive to improving the service life of the capillary wick electrodeposited by the hydrogen bubble template method.

[0016] Compared with traditional methods, the present invention does not require changes to the electrolyte composition and electrolyte temperature, reduces the control requirements for electrolyte concentration and temperature, simplifies process operations, reduces frequent adjustments and maintenance of the electrolyte during production, and further reduces production costs and process complexity.

[0017] Compared with traditional copper powder sintering and wire mesh sintering methods, this method eliminates the complex powder preparation, pressing, and sintering processes, resulting in a simpler process flow and significantly shortened production cycles. This not only reduces production costs but also improves the efficiency of capillary wick manufacturing, making it suitable for large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 and Figure 2 The morphology images of the samples prepared in Comparative Example 1 at different magnifications are shown.

[0019] Figure 3 and Figure 4 These are morphology images of the samples prepared in Example 1 at different magnifications.

[0020] Figure 5 and Figure 6 These are morphology images of the samples prepared in comparative example 3 at different magnifications.

[0021] Figure 7 and Figure 8 These are morphology images of the samples prepared in comparative example 2 at different magnifications.

[0022] Figure 9 and Figure 10 These are morphology images of the samples prepared in Comparative Example 4 at different magnifications.

[0023] Figure 11 and Figure 12 These are morphology images of the samples prepared in Example 2 at different magnifications. DETAILED DESCRIPTION

[0024] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention is further described below with reference to specific examples and accompanying drawings. However, the examples are not intended to limit the present invention. The experimental methods and detection methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified.

[0025] The present invention provides a method for preparing a capillary wick structure by unidirectional pulse electrodeposition, comprising the following steps: The copper substrate to be deposited is polished and cleaned to remove the oxide film and oil stains on the surface of the copper substrate. Then, the copper substrate is used as the cathode and the copper plate is used as the anode to carry out unidirectional pulse current electrodeposition in an electrolyte containing sulfuric acid and copper sulfate.

[0026] The deposited copper substrate is sintered in a reducing atmosphere to obtain a capillary wick structure.

[0027] Compared with traditional electrodeposition methods, the present invention uses pulsed current electrodeposition, eliminating the need to change the electrolyte composition and electrolyte temperature. By controlling the pulse frequency and duty cycle to adjust the copper dendrite length, the prepared dendrites are shorter, have stronger dendrite collapse resistance, and have a more complete porous structure, which helps to increase the service life of the hydrogen bubble template electrodeposition capillary wick. The capillary wick structure prepared by the above preparation method has a honeycomb pore structure with dendrites growing on the pore walls. The pore diameter is 40μm to 300μm, and the dendrite branch length is 0.1μm to 15μm.

[0028] The present invention will be described in detail below through the following examples and comparative examples.

[0029] Example 1 A method for preparing a capillary wick structure by unidirectional pulse electrodeposition comprises the following steps: Step 1: Use a copper plate as the copper substrate to be deposited: polish it smooth with 400-grit and 1200-grit sandpaper in sequence, and then use acetone and alcohol ultrasonic cleaning to remove oil stains on the surface of the copper plate.

[0030] Step 2: Prepare a sulfuric acid-copper sulfate mixed electrolyte with a sulfuric acid concentration of 1.8 mol / L and a copper sulfate concentration of 0.4 mol / L, with water as the solvent, the copper sample as the cathode, and the copper plate as the anode. 2 The samples were subjected to unidirectional pulse current electrodeposition under the current conditions of current density, 0.1 Hz frequency, 15% duty cycle and total time of 600 s.

[0031] Step 3: Place the deposited sample in a sintering furnace, introduce a reducing gas of 95% nitrogen and 5% hydrogen, and sinter at 740°C for 20 min to enhance the mechanical properties.

[0032] Comparative Example 1 Compared with Example 1, no sintering treatment was performed, and the preparation steps were as follows: Step 1: Use a copper plate as the copper substrate to be deposited: polish it smooth with 400-grit and 1200-grit sandpaper in sequence, and then use acetone and alcohol ultrasonic cleaning to remove oil stains on the surface of the copper plate.

[0033] Step 2: Prepare a sulfuric acid-copper sulfate mixed electrolyte with a sulfuric acid concentration of 1.8 mol / L and a copper sulfate concentration of 0.4 mol / L. The copper sample is used as the cathode and the copper plate is used as the anode. 2 The samples were subjected to unidirectional pulse current electrodeposition under the current conditions of current density, 0.1 Hz frequency, 15% duty cycle and total time of 600 s.

[0034] Comparative Example 2 Compared with Example 1, pulse electrodeposition is not used, and the preparation steps are as follows: Step 1: Use a copper plate as the copper substrate to be deposited: polish it smooth with 400-grit and 1200-grit sandpaper in sequence, and then use acetone and alcohol ultrasonic cleaning to remove oil stains on the surface of the copper plate.

[0035] Step 2: Prepare a sulfuric acid-copper sulfate mixed electrolyte with a sulfuric acid concentration of 1.8 mol / L and a copper sulfate concentration of 0.4 mol / L. The copper sample is used as the cathode and the copper plate is used as the anode. 2 The samples were electrodeposited under the current conditions of 1000 Å and 2000 Å current density for a total time of 90 s.

[0036] Step 3: Place the deposited sample in a sintering furnace, introduce a reducing gas of 95% nitrogen and 5% hydrogen, and sinter at 740°C for 20 min to enhance the mechanical properties.

[0037] Comparative Example 3 Compared with Comparative Example 2, no sintering was performed, and the preparation steps were: Step 1: Use a copper plate as the copper substrate to be deposited: polish it smooth with 400-grit and 1200-grit sandpaper in sequence, and then use acetone and alcohol ultrasonic cleaning to remove oil stains on the surface of the copper plate.

[0038] Step 2: Prepare a sulfuric acid-copper sulfate mixed electrolyte with a sulfuric acid concentration of 1.8 mol / L and a copper sulfate concentration of 0.4 mol / L. The copper sample is used as the cathode and the copper plate is used as the anode. 2 The samples were electrodeposited under the current conditions of 1000 Å and 2000 Å current density for a total time of 90 s.

[0039] Figure 1 and Figure 2 These are morphology images of the samples prepared in Comparative Example 1 at different magnifications. Figure 3 and Figure 4 The morphology of the samples prepared in Example 1 at different magnifications are shown. Compared with Comparative Example 1, Example 1 was sintered. Figure 4 and Figure 2 It can be seen that when the sample prepared in Example 1 is sintered at a high temperature, the copper dendrites bond with each other to form coarser grains, and the bond between the copper dendrites and the copper plate becomes stronger under the action of sintering.

[0040] Figure 5 and Figure 6 These are morphology images of the samples prepared in comparative example 3 at different magnifications. Figure 7 and Figure 8 The morphology images of the samples prepared in comparative example 2 at different magnifications are shown respectively. Figure 6 and Figure 8 It can be seen that in the sample prepared after sintering in Comparative Example 2, the bonding between the copper dendrite and the copper plate is stronger.

[0041] Comparing Example 1 with Comparative Example 2, the other conditions are the same, and pulse electrodeposition is not used in Comparative Example 2. Compared with the conventional electrodeposition sample structure in Comparative Example 2, the micropore diameter of the sample prepared in Example 1 is smaller, the dendrite length is shorter, and the porous structure is more complete. Figure 3 and Figure 7 This shows that controlling the duty cycle of the pulse current can effectively reduce the micropore diameter and dendrite length. The average micropore diameter of the sample prepared in Example 1 is about 50 μm. The average micropore diameter of the sample prepared in Comparative Example 2 is about 250 μm.

[0042] Example 2 Step 1: Use a copper plate as the copper substrate to be deposited: polish it smooth with 400-grit and 1200-grit sandpaper in sequence, and then use acetone and alcohol ultrasonic cleaning to remove oil stains on the surface of the copper plate.

[0043] Step 2: Prepare a sulfuric acid-copper sulfate mixed electrolyte with a sulfuric acid concentration of 1.8 mol / L and a copper sulfate concentration of 0.4 mol / L. The copper sample is used as the cathode and the copper plate is used as the anode. 2The samples were subjected to unidirectional pulse current electrodeposition under the current conditions of current density, frequency of 0.03 Hz, duty cycle of 15%, and total time of 180 s.

[0044] Step 3: Place the deposited sample in a sintering furnace, introduce a reducing gas of 95% nitrogen and 5% hydrogen, and sinter at 740 °C for 20 min to enhance the mechanical properties.

[0045] Comparative Example 4 Compared with Example 2, no sintering treatment is performed, and the steps are as follows: Step 1: Use a copper plate as the copper substrate to be deposited: polish it smooth with 400-grit and 1200-grit sandpaper in sequence, and then use acetone and alcohol ultrasonic cleaning to remove oil stains on the surface of the copper plate.

[0046] Step 2: Prepare a sulfuric acid-copper sulfate mixed electrolyte with a sulfuric acid concentration of 1.8 mol / L and a copper sulfate concentration of 0.4 mol / L. The copper sample is used as the cathode and the copper plate is used as the anode. 2 The samples were subjected to unidirectional pulse current electrodeposition under the current conditions of current density, frequency of 0.03 Hz, duty cycle of 15%, and total time of 180 s.

[0047] The structure of the unidirectional pulse electrodeposition sample before and after sintering is as follows: Figure 3 As shown, the sample prepared in Comparative Example 4 is the sample before sintering, and the sample prepared in Example 2 is the sample after sintering. It can be seen that after sintering, the copper dendrites bonded to each other to form coarser grains, and the bond between the copper dendrites and the copper plate became stronger under the action of sintering.

[0048] Figure 9 and Figure 10 These are morphology images of the samples prepared in Comparative Example 4 at different magnifications. Figure 11 and Figure 12 These are morphology images of the samples prepared in Example 2 at different magnifications. Compared with Comparative Example 4, after sintering in Example 2, the copper dendrites bonded to each other to form coarser grains, and the bond between the copper dendrites and the copper plate was more firmly established under the action of sintering.

[0049] Comparison between Example 2 and Comparative Example 2 shows that pulse electrodeposition was not used in Comparative Example 2. Figure 11 and Figure 7 ,visible, Figure 11 The sample prepared in Example 2 has a smaller micropore diameter, a shorter dendrite length, and a more complete porous structure. The average micropore diameter of the sample prepared in Example 2 is about 100 μm.

[0050] Example 3 A method for preparing a capillary wick structure by unidirectional pulse electrodeposition comprises the following steps: Step 1: Use a copper plate as the copper substrate to be deposited: polish it smooth with 400-grit and 1200-grit sandpaper in sequence, and then use acetone and alcohol ultrasonic cleaning to remove oil stains on the surface of the copper plate.

[0051] Step 2: Prepare a sulfuric acid-copper sulfate mixed electrolyte with a sulfuric acid concentration of 1.8 mol / L and a copper sulfate concentration of 0.4 mol / L. The copper sample is used as the cathode and the copper plate is used as the anode. 2 The samples were subjected to unidirectional pulse current electrodeposition under the current conditions of current density, 0.1 Hz frequency, 10% duty cycle and total time of 600 s.

[0052] Step 3: Place the deposited sample in a sintering furnace, introduce a reducing gas of 95% nitrogen and 5% hydrogen, and sinter at 740°C for 20 min to enhance the mechanical properties.

[0053] Example 4 A method for preparing a capillary wick structure by unidirectional pulse electrodeposition comprises the following steps: Step 1: Use a copper plate as the copper substrate to be deposited: polish it smooth with 400-grit and 1200-grit sandpaper in sequence, and then use acetone and alcohol ultrasonic cleaning to remove oil stains on the surface of the copper plate.

[0054] Step 2: Prepare a sulfuric acid-copper sulfate mixed electrolyte with a sulfuric acid concentration of 1.8 mol / L and a copper sulfate concentration of 0.4 mol / L. The copper sample is used as the cathode and the copper plate is used as the anode. 2 The samples were subjected to unidirectional pulse current electrodeposition under the current conditions of current density, 0.1 Hz frequency, 15% duty cycle and total time of 180 s.

[0055] Step 3: Place the deposited sample in a sintering furnace, introduce a reducing gas of 95% nitrogen and 5% hydrogen, and sinter at 740°C for 20 min to enhance the mechanical properties.

[0056] Example 5 A method for preparing a capillary wick structure by unidirectional pulse electrodeposition comprises the following steps: Step 1: Use a copper plate as the copper substrate to be deposited: polish it smooth with 400-grit and 1200-grit sandpaper in sequence, and then use acetone and alcohol ultrasonic cleaning to remove oil stains on the surface of the copper plate.

[0057] Step 2: Prepare a sulfuric acid-copper sulfate mixed electrolyte with a sulfuric acid concentration of 1.8 mol / L and a copper sulfate concentration of 0.4 mol / L. The copper sample is used as the cathode and the copper plate is used as the anode. 2 The samples were subjected to unidirectional pulse current electrodeposition under the current conditions of current density, frequency of 10 Hz, duty cycle of 50%, and total time of 600 s.

[0058] Step 3: Place the deposited sample in a sintering furnace, introduce a reducing gas of 95% nitrogen and 5% hydrogen, and sinter at 740°C for 20 min to enhance the mechanical properties.

[0059] Example 6 A method for preparing a capillary wick structure by unidirectional pulse electrodeposition comprises the following steps: Step 1: Use a copper plate as the copper substrate to be deposited: polish it smooth with 400-grit and 1200-grit sandpaper in sequence, and then use acetone and alcohol ultrasonic cleaning to remove oil stains on the surface of the copper plate.

[0060] Step 2: Prepare a sulfuric acid-copper sulfate mixed electrolyte with a sulfuric acid concentration of 1.8 mol / L and a copper sulfate concentration of 0.4 mol / L. The copper sample is used as the cathode and the copper plate is used as the anode. 2 The sample was subjected to unidirectional pulse current electrodeposition under the current conditions of current density, frequency of 0.1 Hz, duty cycle of 15%, and total time of 600 s.

[0061] Step 3: Place the deposited sample in a sintering furnace, introduce a reducing gas of 95% nitrogen and 5% hydrogen, and sinter at 740°C for 20 min to enhance the mechanical properties.

[0062] Example 7 A method for preparing a capillary wick structure by unidirectional pulse electrodeposition comprises the following steps: Step 1: Use a copper plate as the copper substrate to be deposited: polish it smooth with 400-grit and 1200-grit sandpaper in sequence, and then use acetone and alcohol ultrasonic cleaning to remove oil stains on the surface of the copper plate.

[0063] Step 2: Prepare a sulfuric acid-copper sulfate mixed electrolyte with a sulfuric acid concentration of 1.8 mol / L and a copper sulfate concentration of 0.4 mol / L. The copper sample is used as the cathode and the copper plate is used as the anode. 2 The sample was subjected to unidirectional pulse current electrodeposition under the current conditions of current density, frequency of 0.1 Hz, duty cycle of 15%, and total time of 600 s.

[0064] Step 3: Place the deposited sample in a sintering furnace, introduce a reducing gas of 95% nitrogen and 5% hydrogen, and sinter at 740°C for 20 min to enhance the mechanical properties.

[0065] Example 8 A method for preparing a capillary wick structure by unidirectional pulse electrodeposition comprises the following steps: Step 1: Use a copper plate as the copper substrate to be deposited: polish it smooth with 400-grit and 1200-grit sandpaper in sequence, and then use acetone and alcohol ultrasonic cleaning to remove oil stains on the surface of the copper plate.

[0066] Step 2: Prepare a sulfuric acid-copper sulfate mixed electrolyte with a sulfuric acid concentration of 1.8 mol / L and a copper sulfate concentration of 0.4 mol / L. The copper sample is used as the cathode and the copper plate is used as the anode. 2 The samples were subjected to unidirectional pulse current electrodeposition under the current conditions of current density, frequency of 0.5 Hz, duty cycle of 15%, and total time of 600 s.

[0067] Step 3: Place the deposited sample in a sintering furnace, introduce a reducing gas of 95% nitrogen and 5% hydrogen, and sinter at 680°C for 20 min to enhance the mechanical properties.

[0068] Example 9 A method for preparing a capillary wick structure by unidirectional pulse electrodeposition comprises the following steps: Step 1: Use a copper plate as the copper substrate to be deposited: polish it smooth with 400-grit and 1200-grit sandpaper in sequence, and then use acetone and alcohol ultrasonic cleaning to remove oil stains on the surface of the copper plate.

[0069] Step 2: Prepare a sulfuric acid-copper sulfate mixed electrolyte with a sulfuric acid concentration of 1.8 mol / L and a copper sulfate concentration of 0.4 mol / L. The copper sample is used as the cathode and the copper plate is used as the anode. 2 The sample was subjected to unidirectional pulse current electrodeposition under the current conditions of current density, frequency of 0.1 Hz, duty cycle of 15%, and total time of 600 s.

[0070] Step 3: Place the deposited sample in a sintering furnace, introduce a reducing gas of 95% nitrogen and 5% hydrogen, and sinter at 840°C for 20 min to enhance the mechanical properties.

[0071] Similarly, in Examples 3 through 9 above, the capillary wick structures fabricated using pulsed current electrodeposition effectively reduced the micropore diameter and dendrite length compared to capillary wick structures fabricated using conventional electrodeposition, thus avoiding the problem of structural collapse caused by excessively long dendrites during conventional electrodeposition. These details will not be elaborated upon.

[0072] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications of the present invention fall within the scope of the claims and their equivalents, such changes and modifications are intended to be included.

Claims

1. A method for preparing a capillary wick structure by unidirectional pulse electrodeposition, characterized in that: The following steps are involved: After the copper substrate to be deposited is polished and cleaned, the copper substrate is used as the cathode and the copper plate as the anode. Unidirectional pulse electrodeposition is carried out in an electrolyte containing sulfuric acid and copper sulfate. The micropore diameter and dendrite length are reduced by controlling the pulse frequency and duty cycle. The deposited copper substrate is sintered in a reducing atmosphere to obtain a capillary wick structure.

2. The method for preparing a capillary wick structure by unidirectional pulse electrodeposition according to claim 1, wherein: During unidirectional pulse electrodeposition, the current density is 0.05A / cm 2 ~3A / cm 2 , frequency is 0.03Hz~10Hz, and duty cycle is 10%~99%.

3. The method for preparing a capillary wick structure by unidirectional pulse electrodeposition according to claim 2, wherein: The current density is 0.6A / cm 2 ~1.2A / cm 2 , frequency is 0.05Hz~0.5Hz, and duty cycle is 10%~99%.

4. The method for preparing a capillary wick structure by unidirectional pulse electrodeposition according to claim 1, wherein: In the electrolyte, the concentration of hydrogen ions is 0.5 mol / L~4 mol / L, the concentration of copper ions is 0.1 mol / L~0.8 mol / L, and the solvent is water.

5. The method for preparing a capillary wick structure by unidirectional pulse electrodeposition according to claim 1, characterized in that: The sintering temperature is 680°C to 840°C, and the sintering time is 10 minutes to 120 minutes.

6. The method for preparing a capillary wick structure by unidirectional pulse electrodeposition according to claim 1, characterized in that: The copper substrate material to be deposited is red copper or pure copper.

7. A capillary wick structure, characterized in that The method according to any one of claims 1 to 6 is used for preparation.

8. The capillary wick structure according to claim 7, characterized in that The capillary wick structure has macropores with a pore diameter of 40 μm to 300 μm, copper dendrites grow on the pore walls of the macropores, and the branch length of the copper dendrites is 0.1 μm to 15 μm.

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