Surface nanocrystallization metal radiator and preparation method thereof

Abstract

The invention relates to the technical field of heat dissipation, in particular to a surface nanocrystallization metal radiator and a preparation method thereof. The nano-structure aims at improving the surface emissivity and promoting natural convection heat dissipation, and the heat dissipation performance of an existing metal radiator is improved. According to the main scheme, metal serves as a substrate layer, and a three-dimensional porous interconnected honeycomb-like structure metal nanometer layer grows on the surface of the metal. By utilizing the three-dimensional porous interconnected nano-structure layer, the flow of air in the three-dimensional pore diameter can be increased, the natural convection heat dissipation capability is effectively improved, and meanwhile, the radiation heat dissipation capability is effectively improved by virtue of the high surface emissivity characteristic, so that the heat dissipation performance of the radiator is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of heat dissipation, and particularly to a surface-nanostructured metal heat sink and a preparation method thereof. Background Art

[0002] With the increasing miniaturization and high performance of electronic devices, the heat dissipation problem has become a major bottleneck restricting the development of electronic devices. In modern electronic products, especially in high-performance computing devices, LED lighting, laser devices, and various power electronic devices, the heat sink, as a key thermal management component, bears the responsibility of quickly transferring the heat generated during the operation of the device. To ensure the stable operation of the device and extend its service life, efficient heat sink design and technology are particularly important.

[0003] Traditional metal heat sinks (such as those made of copper and aluminum) usually improve the heat dissipation efficiency by increasing the macroscopic heat dissipation area (such as fin and pin structures) or optimizing the air duct design. However, such methods have inherent limitations:

[0004] 1. Low thermal radiation efficiency: The thermal emissivity of metal materials themselves is relatively low (for example, the emissivity of copper is about 0.15). Especially in high-temperature environments, the contribution of thermal radiation to the overall heat dissipation is limited, resulting in the heat dissipation performance being difficult to meet the requirements of high-power scenarios.

[0005] 2. Limited specific surface area: The method of relying on macroscopic structures (such as fins) to expand the heat dissipation area is easily restricted by space, and it is difficult to further optimize the solid / gas contact interface at the microscale, which limits the improvement of the natural convection efficiency.

[0006] 3. Process complexity and cost: Although existing surface nanostructuring technologies (such as laser etching and chemical vapor deposition) can improve the heat dissipation performance through micro-nano structures, they generally have problems such as complex processes, expensive equipment, and difficulty in large-scale production. For example, laser processing requires precise control of energy parameters, has poor adaptability to substrate materials, and it is difficult to ensure uniformity on large-area or complex-structure surfaces.

[0007] To address these issues, researchers and engineers have made numerous innovative attempts in the field of heat dissipation technology. Among them, surface nanocrystallization technology, as a new method, has received extensive attention because it can significantly improve the thermophysical properties of materials, especially in terms of heat dissipation efficiency. By fabricating nanostructures on the surface of metal radiators, not only can the surface specific surface area be increased, but also the surface emissivity of the material can be significantly improved, thereby optimizing the heat dissipation effect. Research shows that nanostructures generated on the aluminum surface through simple laser treatment technology significantly increase the thermal radiation rate of the radiator, enabling it to exhibit excellent heat dissipation performance in high-power density applications. In addition, another study also indicates that preparing nanoparticles on the surface of copper radiators can increase the surface specific surface area, thereby improving the heat dissipation efficiency. Especially in high-temperature environments, the copper nano-surface has a higher thermal emissivity. However, the above technologies still have the following problems:

[0008] Insufficient structural stability: Laser treatment is prone to causing thermal damage to the substrate, and the bonding force between the nanoparticle layer and the substrate is weak, making it easy to fall off during long-term use;

[0009] Poor process universality: Existing methods are difficult to uniformly construct nano-layers on the surfaces of complex structures (such as fins, curved surfaces), which limits the actual application scenarios;

[0010] High cost: Fabricating nanostructures on the metal surface using lasers usually requires complex equipment and high process control precision, resulting in high production costs and difficulty in large-scale application.

[0011] Based on this, there is an urgent need to develop a surface nanocrystallization method that is simple in process, low in cost, and applicable to various metal substrates. By designing micro-nano structures with both high radiation rate and enhanced convective characteristics, the performance bottleneck of traditional radiators can be broken through. Summary of the Invention

[0012] The purpose of the present invention is to construct a nanostructure on the surface of a traditional metal radiator that can enhance the surface emissivity and promote natural convection heat dissipation, thereby improving the heat dissipation performance of the existing metal radiator. At the same time, it also has the characteristics of low cost and large-scale preparation.

[0013] To achieve the above purpose, the present invention provides a surface-nanocrystallized metal radiator and its preparation method, which constructs a nanostructure on the surface of a traditional metal radiator that can enhance the surface emissivity and promote natural convection heat dissipation, thereby improving the heat dissipation performance of the existing metal radiator. At the same time, it also has the characteristics of low cost and large-scale preparation.

[0014] To solve the problems existing in the prior art, the technical solution of the present invention is as follows:

[0015] A surface-nanocrystallized metal radiator and its preparation method, at least including:

[0016] A metal substrate layer and a nanostructured layer on the metal surface;

[0017] The material of the metal substrate layer is copper, aluminum, nickel, silver, steel, copper-aluminum alloy, nickel alloy, or magnesium alloy;

[0018] Furthermore, the metal substrate layer can be a flat metal, a thin film metal, or a traditional metal radiator with macroscopic fins or needles;

[0019] Furthermore, the nanostructured layer on the metal surface is a honeycomb-like structure composed of dendritic nano-copper;

[0020] Furthermore, for the honeycomb-like structure, the pore diameter is 20 microns to 50 microns, the pore spacing is 20 microns to 100 microns, and the thickness is 10 microns to 100 microns;

[0021] The present invention also provides a surface-nanostructured metal radiator and its preparation method. The preparation method includes the following steps:

[0022] Step 1. Ultrasonically clean and dry the metal;

[0023] Step 2. Prepare a copper sulfate electrolyte solution with a certain concentration;

[0024] Step 3. Using the metal substrate layer as the working electrode, a Pt sheet as the counter electrode, and the copper sulfate solution as the electrolyte, electro-deposit for a certain time at a current density of 1 A / cm 2 ~3 A / cm 2 to generate a nanostructured layer attached to the metal surface;

[0025] Step 4. Rinse it repeatedly with deionized water and absolute ethanol to remove the excess electrolyte. Dry it in a vacuum drying oven at 100 - 150 °C for 10 - 30 min to obtain the surface-nanostructured metal radiator;

[0026] Furthermore, in Step 1, ultrasonically clean the metal substrate layer in acetone, deionized water, hydrochloric acid, and deionized water for 20 min in sequence, and then place it in a drying oven at 60 °C for drying and reserve it.

[0027] Furthermore, the concentration of the copper sulfate electrolyte solution described in Step 2 is 30 - 60 g / L.

[0028] Furthermore, the deposition current density described in Step 3 is 1 - 3 A / cm 2 .

[0029] Furthermore, the deposition time described in Step 3 is 5 - 25 S.

[0030] Furthermore, the drying described in Step 4 is carried out in a vacuum drying oven at 100 - 150 °C for 10 - 30 min.

[0031] The surface-nanostructured metal heat sink provided by the present invention and its preparation method significantly improve the heat dissipation performance and solve the limitations of the prior art through innovative structural design and process optimization. The specific beneficial effects are as follows:

[0032] 1. Significant improvement in thermal radiation efficiency

[0033] Traditional metal heat sinks (such as copper and aluminum) have a low surface emissivity (usually below 0.2), resulting in limited thermal radiation contribution. In the present invention, a three-dimensional porous interconnected honeycomb-like structure composed of dendritic nano-copper is constructed on the surface of the metal substrate, increasing the surface emissivity from 0.15 to 0.89 (as Figure 4 shown), and the radiation heat dissipation efficiency in the 3-18μm infrared band is increased by nearly 6 times. This structure enhances the multiple scattering effect of infrared radiation through the rough surface and three-dimensional porous morphology of the nano-copper dendrites, thus greatly improving the thermal radiation efficiency.

[0034] 2. Optimization of solid / gas convective heat transfer efficiency

[0035] The nano-structured layer has a honeycomb-like porous feature with a pore diameter of 20-50μm and a pore spacing of 20-100μm (as Figure 1 shown). Its three-dimensional interconnected channels provide an efficient gas flow channel for natural convection, effectively reducing the thickness of the thermal boundary layer. At the same time, the micro-nano composite structure formed by dendritic nano-copper increases the specific surface area by dozens of times compared with the traditional metal surface, significantly increasing the solid / gas contact area. Experiments show that( Figure 5 ) under a heat load of 0.22W / cm 2 , the heat sink of the present invention can stably reduce the temperature by about 13°C compared with the pure copper substrate, fully verifying the improvement of its convective heat dissipation performance.

[0036] 3. Strong compatibility and adaptability to complex structures

[0037] The metal substrate can be made of various materials such as copper, aluminum, and alloys, and supports any macroscopic structure such as flat plates, thin films, fins / pins (as Figure 2 , 3 shown). Through the electrodeposition process, the nano-structured layer can grow uniformly on complex geometric surfaces, overcoming the dependence of traditional micro-nano processing technologies (such as laser etching) on flat surfaces. This characteristic enables the present invention to seamlessly adapt to the existing heat sink design and achieve performance upgrades without additional structural modifications.

[0038] 4. Simple process and significant cost advantage

[0039] The preparation method uses a one-step electrodeposition technique, at 13A / cm 2The construction of the nanostructure layer can be completed in only 5 - 25 seconds under high current density (Examples 1, 5, and 6), and the efficiency is more than 100 times higher than that of processes such as laser nanonization. The electrolyte uses copper sulfate and glucose as raw materials, and the crystallization kinetics is regulated by acidification to achieve the controllable growth of dendritic nanocopper. The entire process (electrodeposition step) does not require complex equipment or a vacuum environment, and the single-piece processing cost is less than 10% of the traditional method, having the potential for large-scale industrial application.

[0040] 5. Excellent structural stability and durability

[0041] The nanostructure layer and the metal substrate form a metallurgical bond through electrodeposition, with high bonding strength, and there is no peeling phenomenon after thermal cycle testing (-40 - 150 °C cycling 100 times). The porosity (30% - 60%) and thickness (10 - 100 μm) of the honeycomb-like structure can be regulated according to requirements, avoiding structural collapse while ensuring mechanical strength. The drying process (vacuum treatment at 100 - 150 °C) further removes residual stress, ensuring long-term use stability.

[0042] 6. The design concept of the present invention is novel and the preparation operation is simple. It can conveniently prepare a nanostructured surface on a metal plate, metal film, or the surface of a complex structure metal, and can effectively solve the problems faced by traditional metal fin heat sinks and micro-nano processing of metal surfaces. Description of the Drawings

[0043] Figure 1 Optical picture of the surface-nanostructured copper sheet and local enlarged microscopic picture in Example 1;

[0044] Figure 2 Optical picture of the surface-nanostructured copper film in Example 2;

[0045] Figure 3 Optical picture of the surface-nanostructured copper fin heat sink in Example 3;

[0046] Figure 4 Emissivity spectrum of the surface-nanostructured copper sheet heat sink prepared in Example 1;

[0047] Figure 5 Comparison chart of the heat dissipation effect of the surface-nanostructured copper sheet heat sink prepared in Example 1. Detailed Description of the Invention

[0048] The above solution is further described below in combination with specific examples. The preferred examples of the present invention are described in detail as follows:

[0049] In the examples, unless otherwise specified, all raw materials are commercially available and do not require further purification.

[0050] Example 1

[0051] Step 1: Using a flat metal Cu as the substrate (with dimensions of 20×20×0.5 mm), ultrasonically clean the Cu in acetone, deionized water, hydrochloric acid, and deionized water for 20 min to remove surface oil stains and impurities, and then place it in a drying oven for drying at 60 °C for later use;

[0052] Step 2: Weigh 7.5 g of CuSO 4 ·5H 2 O and 5 g of glucose into 250 ml of deionized water, stir for a period of time, and then add 10 ml of concentrated sulfuric acid dropwise to prepare a copper sulfate electrolyte solution;

[0053] Step 3: Using the metal substrate as the working electrode, a Pt sheet as the counter electrode, and the copper sulfate solution as the electrolyte, electro-deposit for 25 s at a current density of 3 A / cm 2 to generate a nanostructured layer attached to the metal surface. The thickness of the nanostructured layer is about 70 μm, the pore diameter is about 50 μm, and the pore spacing is about 20 μm;

[0054] Step 4: Rinse it repeatedly with deionized water and absolute ethanol to remove the excess electrolyte. Dry it in a vacuum drying oven at 120 °C for 20 min to obtain a surface-nanostructured metal radiator.

[0055] Example 2

[0056] Step 1: Using a thin-film metal Cu (with a thickness of 10 μm) as the substrate, ultrasonically clean the Cu in acetone, deionized water, hydrochloric acid, and deionized water for 20 min to remove surface oil stains and impurities, and then place it in a drying oven for drying at 60 °C for later use;

[0057] Step 2: Weigh 7.5 g of CuSO 4 ·5H 2 O and 5 g of glucose into 250 ml of deionized water, stir for a period of time, and then add 10 ml of concentrated sulfuric acid dropwise to prepare a copper sulfate electrolyte solution;

[0058] Step 3: Using the metal substrate as the working electrode, a Pt sheet as the counter electrode, and the copper sulfate solution as the electrolyte, electro-deposit for 25 s at a current density of 3 A / cm 2 to generate a nanostructured layer attached to the metal surface. The thickness of the nanostructured layer is about 70 μm, the pore diameter is about 50 μm, and the pore spacing is about 20 μm;

[0059] Step 4: Rinse it repeatedly with deionized water and absolute ethanol to remove the excess electrolyte. Dry it in a vacuum drying oven at 120 °C for 20 min to obtain a surface-nanostructured metal radiator.

[0060] Example 3

[0061] Step 1: Using the finned metal radiator as the substrate, ultrasonically clean the finned metal radiator in acetone, deionized water, hydrochloric acid, and deionized water for 20 min to remove surface oil stains and impurities, and then place it in a drying oven at 60 °C for drying, and set aside;

[0062] Step 2: Weigh 7.5 g of CuSO 4 ·5H 2 O and 5 g of glucose in 250 ml of deionized water, stir for a period of time, and then add 10 ml of concentrated sulfuric acid dropwise to prepare a copper sulfate electrolyte solution;

[0063] Step 3: Using the finned metal radiator as the working electrode, a Pt sheet as the counter electrode, and the copper sulfate solution as the electrolyte, electro-deposit at a current density of 3 A / cm 2 for 25 s to form a nanostructured layer attached to the metal surface. The thickness of the nanostructured layer is about 70 μm, the pore diameter is about 50 μm, and the pore spacing is about 20 μm;

[0064] Step 4: Rinse it repeatedly with deionized water and absolute ethanol to remove the excess electrolyte. Dry it in a vacuum drying oven at 120 °C for 20 min to obtain a surface-nanostructured metal radiator.

[0065] Example 4

[0066] Step 1: Using a flat metal Cu as the substrate, ultrasonically clean the Cu in acetone, deionized water, hydrochloric acid, and deionized water for 20 min to remove surface oil stains and impurities, and then place it in a drying oven at 60 °C for drying, and set aside;

[0067] Step 2: Weigh 7.5 g of CuSO 4 ·5H 2 O and 5 g of glucose in 250 ml of deionized water, stir for a period of time, and then add 20 ml of concentrated sulfuric acid dropwise to prepare a copper sulfate electrolyte solution;

[0068] Step 3: Using the metal substrate as the working electrode, a Pt sheet as the counter electrode, and the copper sulfate solution as the electrolyte, electro-deposit at a current density of 3 A / cm 2 for 25 s to form a nanostructured layer attached to the metal surface. The thickness of the nanostructured layer is about 70 μm, the pore diameter is about 50 μm, and the pore spacing is about 20 μm;

[0069] Step 4: Rinse it repeatedly with deionized water and absolute ethanol to remove the excess electrolyte. Dry it in a vacuum drying oven at 120 °C for 20 min to obtain a surface-nanostructured metal radiator.

[0070] Example 5

[0071] Step 1: Use flat metal Cu as the substrate. Ultrasonically clean the Cu in acetone, deionized water, hydrochloric acid, and deionized water for 20 min to remove surface oil stains and impurities, and then place it in a drying oven at 60 °C for drying for later use;

[0072] Step 2: Weigh 7.5 g of CuSO 4 ·5H 2 O and 5 g of glucose into 500 ml of deionized water, stir for a period of time, and then add 10 ml of concentrated sulfuric acid dropwise to prepare a copper sulfate electrolyte solution;

[0073] Step 3: Use the metal substrate as the working electrode, a Pt sheet as the counter electrode, and the copper sulfate solution as the electrolyte. Electroplate at a current density of 1 A / cm 2 for 25 s to generate a nanostructured layer attached to the metal surface. The thickness of the nanostructured layer is about 70 μm, the pore diameter is about 30 μm, and the pore spacing is about 20 μm;

[0074] Step 4: Rinse it repeatedly with deionized water and absolute ethanol to remove the excess electrolyte. Dry it in a vacuum drying oven at 120 °C for 20 min to obtain a surface-nanostructured metal radiator.

[0075] Example 6

[0076] Step 1: Use flat metal Cu as the substrate. Ultrasonically clean the Cu in acetone, deionized water, hydrochloric acid, and deionized water for 20 min to remove surface oil stains and impurities, and then place it in a drying oven at 60 °C for drying for later use;

[0077] Step 2: Weigh 7.5 g of CuSO 4 ·5H 2 O and 5 g of glucose into 500 ml of deionized water, stir for a period of time, and then add 10 ml of concentrated sulfuric acid dropwise to prepare a copper sulfate electrolyte solution;

[0078] Step 3: Use the metal substrate as the working electrode, a Pt sheet as the counter electrode, and the copper sulfate solution as the electrolyte. Electroplate at a current density of 3 A / cm 2 for 5 s to generate a nanostructured layer attached to the metal surface. The thickness of the nanostructured layer is about 20 μm, the pore diameter is about 50 μm, and the pore spacing is about 20 μm;

[0079] Step 4: Rinse it repeatedly with deionized water and absolute ethanol to remove the excess electrolyte. Dry it in a vacuum drying oven at 120 °C for 20 min to obtain a surface-nanostructured metal radiator.

[0080] Figure 1 It is the optical picture and the partial enlarged microscopic picture of the surface-nanostructured copper sheet in Example 1;

[0081] FromFigure 1 It can be seen from [description] that the surface-nanostructured metal radiator prepared in Example 1 presents a typical three-dimensional porous interconnected network structure, and the pore size ranges from about 40 μm to about 40 μm.

[0082] Figure 2 This is the optical picture of the surface-nanostructured copper film in Example 2;

[0083] Figure 3 This is the optical picture of the surface-nanostructured copper fin radiator in Example 3;

[0084] From Figure 2 、 3 it can be seen that the metal substrate of the surface-nanostructured metal radiator can be any structure of metal.

[0085] Figure 4 This is the emissivity spectrum of the surface-nanostructured copper sheet radiator prepared in Example 1;

[0086] From Figure 4 it can be seen that in the wavelength range of 3 - 18 μm, the average emissivities of pure Cu and the surface-nanostructured metal radiator are 0.15 and 0.89 respectively. The surface-nanostructured metal radiator can effectively increase the emissivity value of the metal substrate.

[0087] Figure 5 This is the comparison chart of the heat dissipation effect of the surface-nanostructured copper sheet radiator prepared in Example 1;

[0088] From Figure 5 it can be seen that under the power density of 0.22 W / cm 2 , a heating test is carried out for up to 10 h. During the test, there is no obvious fluctuation. Compared with pure Cu, the temperature is stably reduced by about 13 °C, which indicates that the prepared surface-nanostructured metal radiator has better heat dissipation effect and thermal stability.

Claims

1. A surface nano-metal heat sink, characterized in that: The invention comprises a metal substrate layer and a nanostructure layer formed on the surface of the metal substrate layer. The nanostructure layer is a three-dimensional porous interconnected honeycomb structure composed of dendrite-shaped nano copper.

2. The surface nano-metal heat sink according to claim 1, characterized in that: The metal substrate layer material is at least one of copper, aluminum, nickel, silver, steel, copper-aluminum alloy, nickel alloy or magnesium alloy.

3. The surface nano-metal heat sink according to claim 2, characterized in that: The metal substrate layer is a flat metal, a thin film metal, or any metal heat sink with macroscopic fins or fin pins.

4. A surface nano-metal heat sink according to claim 1, characterized in that: Honeycomb-like structure, with a pore size of 20 microns to 50 microns, a pore spacing of 20 microns to 100 microns, and a thickness of 10 microns to 100 microns.

5. A surface nano-metal heat sink and a preparation method thereof, characterized in that: The preparation method comprises the following steps: Step 1. Surface pretreatment of the metal substrate: ultrasonic cleaning of the metal substrate with acetone, deionized water, hydrochloric acid and deionized water for 20 minutes each, and drying at 60°C for later use; Step 2. prepare a copper sulfate electrolyte with a concentration of 5 to 20 g / L; Step 3. Electrodeposition treatment: Use the metal substrate layer as the working electrode, the Pt sheet as the counter electrode, and the copper sulfate solution as the electrolyte at 1A / cm 2 ~3A / cm 2 Performing an electrodeposition treatment for 5 to 25 seconds at a current density of , to form a nanostructured layer on the surface of the metal substrate; Step 4. Rinse it repeatedly with deionized water and anhydrous ethanol to remove excess electrolyte, dry it in a vacuum drying oven at 100-150° C. for 10-30 minutes to obtain a surface nano-metal heat sink.

6. The preparation method according to claim 4, characterized in that: The copper sulfate electrolyte in step (2) is prepared by the following method: copper sulfate crystals and glucose are dissolved in deionized water at a mass ratio of 1.5:1, and then 40 to 80 ml of concentrated sulfuric acid is added per liter of electrolyte for acidification.

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