Foamed metal-based atmospheric water-absorbing passive heat dissipation material and preparation method
By growing interconnected carbon nanotubes on a foamed metal framework and introducing a hygroscopic agent, the problem of insufficient heat dissipation of existing passive heat dissipation materials under high power density is solved, achieving efficient and stable heat dissipation and low-cost preparation.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- UNIV OF ELECTRONICS SCI & TECH OF CHINA
- Filing Date
- 2025-02-12
- Publication Date
- 2026-07-10
AI Technical Summary
Existing passive heat dissipation materials are insufficient in heat dissipation capacity under high power density and complex thermal environments. Multi-material composite heat sinks have poor interfacial thermal resistance control and long-term reliability. It is difficult to achieve large-scale preparation of new heat dissipation materials with high consistency and low cost.
Using foamed metal as a framework, interconnected carbon nanotubes are grown on its surface by flame method, and a hygroscopic agent is introduced to prepare a foamed metal-based atmospheric water-absorbing passive heat dissipation material. The high thermal conductivity and radiative heat dissipation capacity of carbon nanotubes are utilized, combined with the phase change process of water molecules to absorb heat.
This technology enables rapid and uniform heat conduction and improved radiative heat dissipation, reducing device temperature, improving heat dissipation efficiency and long-term material stability, and lowering manufacturing costs.
Smart Images
Figure CN119931613B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to high-efficiency passive heat dissipation materials, specifically to a foamed metal-based atmospheric water-absorbing passive heat dissipation material and its preparation method. Background Technology
[0002] With the rapid development of modern electronic technology, electronic devices are playing an increasingly important role in industries such as aerospace and portable electronic devices. High integration, lightweight design, and high power output have become development trends in electronic devices. However, as integration levels continue to increase, feature sizes gradually decrease, leading to a rapid increase in power density and a significant rise in system temperature. Studies show that approximately 55% of electronic device failures are related to high temperatures. Therefore, effectively managing heat to ensure electronic devices operate within their optimal operating temperature range has become a critical issue that urgently needs to be addressed.
[0003] Passive cooling technology is a heat dissipation method that requires no additional energy and is widely used in electronic devices, machinery, and construction. By optimizing materials, structural design, and natural heat exchange processes, passive cooling technology can effectively improve heat transfer efficiency, reduce equipment operating temperature, and extend service life. Its main principles include heat transfer mechanisms such as conduction, convection, and radiation, and performance is improved through the high thermal conductivity, surface properties, and optimized geometry of materials. For example, in the heat dissipation of electronic devices, new materials such as high thermal conductivity metals and graphene, as well as innovative structural designs such as fins and microchannels, are often used to enhance heat dissipation capabilities.
[0004] In recent years, research on passive heat dissipation technology has gradually shifted towards the development of new materials and the design of multifunctional composite structures. Materials with high thermal conductivity and high specific surface area, such as graphene, carbon nanotubes, and metal-organic frameworks (MOFs), have attracted widespread attention due to their excellent thermal conductivity and lightweight properties. Furthermore, multi-material composite heat sinks that combine heat dissipation with other functions have become an important means of improving heat dissipation efficiency and overall equipment performance. For example, transparent heat dissipation coatings, deformable heat dissipation devices, and thermal management systems with integrated power generation functions all demonstrate the diversified development trend of passive heat dissipation technology.
[0005] However, passive heat dissipation technology still faces several pressing issues. On one hand, the thermal conductivity of existing materials is not yet ideal, especially under high power density and complex thermal environments, where their heat dissipation capacity may be insufficient. On the other hand, controlling the interfacial thermal resistance and ensuring long-term reliability of multi-material composite heat sinks remain key technological bottlenecks. Furthermore, the large-scale fabrication of novel heat dissipation materials and devices with high consistency and low cost also restricts the practical application of the technology. Therefore, future research needs to further advance breakthroughs in new material development, structural design optimization, and industrial manufacturing technologies to promote the comprehensive development of passive heat dissipation technology. Summary of the Invention
[0006] The purpose of this invention is to address the problems existing in the background technology by proposing a foamed metal-based atmospheric water-absorbing passive heat dissipation material and its preparation method. This invention uses foamed metal as a framework, and grows a layer of interconnected carbon nanotubes on the surface of the framework using a flame method. Utilizing the interconnected structure of the carbon nanotubes, heat can be rapidly and uniformly conducted to the heat dissipation surface, effectively improving radiative heat dissipation capacity due to their high surface emissivity. Based on this, a hygroscopic agent is introduced into the carbon nanotube system to prepare a foamed metal-based atmospheric water-absorbing passive heat dissipation material with significant heat dissipation performance. This foamed metal-based atmospheric water-absorbing passive heat dissipation material can absorb water molecules from the atmospheric environment and anchor them within the material through a siphon effect. When used for device heat dissipation, water molecules change from a solid / liquid state to a gaseous state during the temperature rise process. This phase transition process absorbs a large amount of heat, thereby effectively suppressing the temperature rise of the device being cooled.
[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0008] A foamed metal-based atmospheric water-absorbing passive heat dissipation material and its preparation method include the following steps:
[0009] Step 1. Using foamed metal as a skeleton, the foamed metal is ultrasonically cleaned in acetone, deionized water, hydrochloric acid and deionized water for 20 minutes in sequence to remove surface oil and impurities, and then placed in a drying oven at 60°C to dry for later use.
[0010] Step 2. Prepare a carbon nanotube growth precursor solution with a concentration of 0.1 g / ml to 0.3 g / ml;
[0011] Step 3. Immerse the dried foam metal from Step 1 in a carbon nanotube growth precursor solution for 10-20 seconds, then remove it and burn it under an alcohol lamp for 10-30 seconds. Repeat the "immersion and burning" process 5-30 times to form interconnected carbon nanotubes on the foam metal framework.
[0012] Step 4. Prepare a desiccant solution with a concentration of 0.1–2 mol / L;
[0013] Step 5. Immerse the carbon nanotube-loaded metal foam obtained in Step 3 in a desiccant solution, sonicate for 1-5 min, and then soak for 30 min; after removal, dry in a vacuum drying oven at 100-150℃ for 10-30 min to obtain a metal foam-based atmospheric water-absorbing passive heat dissipation material.
[0014] Furthermore, the solute in the carbon nanotube growth precursor solution described in step 2 is one or more of cobalt acetylacetone, iron acetylacetone, and silver acetylacetone, and the solvent is ethanol.
[0015] Furthermore, the solute in the desiccant solution described in step 4 is one or more of lithium chloride, calcium chloride, and lithium bromide, and the solvent is water or ethanol.
[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0017] 1. This invention uses foamed metal as a framework and forms interconnected carbon nanotubes on the framework, which can quickly and evenly conduct heat to the heat dissipation surface, effectively improving the radiative heat dissipation capacity due to its high surface emissivity.
[0018] 2. This invention uses a flame method to prepare carbon nanotubes on foamed metal. The process is simple and low-cost, and has the characteristics of high thermal conductivity and high emissivity, which can enable heat to be quickly and evenly conducted to the heat dissipation surface for heat dissipation.
[0019] 3. In the process of preparing carbon nanotubes, this invention adjusts the concentration of the carbon nanotube solution and the number of soaking-burning cycles to load more carbon nanotubes onto the foam metal skeleton, which can effectively improve the thermal conductivity of the heat transfer path and increase the surface thermal emissivity, thereby enhancing the heat dissipation performance.
[0020] 4. In this invention, when loading the desiccant material, ultrasonic treatment is used followed by soaking. Ultrasonic treatment can effectively reduce the agglomeration of the desiccant material, promote its better loading on the foam metal skeleton, and further increase its specific surface area. This is beneficial for phase change materials such as calcium chloride to adsorb moisture in the air. The evaporation phase change of water can remove a large amount of heat, further improving the heat dissipation efficiency. Attached Figure Description
[0021] Figure 1 The images shown are scanning electron microscope (SEM) images of the samples prepared in Example 1; where a is an SEM image of the carbon nanotubes prepared in Example 1, and b is an SEM image of the foam metal-based atmospheric water-absorbing passive heat dissipation material prepared in Example 1.
[0022] Figure 2 Here is an elemental distribution diagram of the copper-based atmospheric water-absorbing passive heat dissipation material prepared in Example 1; where a is a scanning electron microscope image, b is Ca, c is Cl, and d is the content ratio of each element:
[0023] Figure 3 Temperature comparison curves for cyclic stability testing of the copper-based atmospheric water-absorbing passive heat dissipation material prepared in Example 1 and carbon nanotubes;
[0024] Figure 4 Temperature comparison curves for long-term stability testing of the copper-based atmospheric water-absorbing passive heat dissipation material prepared in Example 1 and carbon nanotubes. Detailed Implementation
[0025] The above solution will be further described below with reference to specific embodiments. Preferred embodiments of the present invention are described in detail below:
[0026] In the embodiments, unless otherwise specified, all raw materials are commercially available and do not require further purification.
[0027] Example 1
[0028] Step 1. Using copper foam as a skeleton, the copper foam metal is ultrasonically cleaned in acetone, deionized water, hydrochloric acid and deionized water for 20 minutes in sequence to remove surface oil and impurities. Then it is placed in a drying oven at 60°C to dry for later use.
[0029] Step 2. Weigh 0.3g of cobalt acetylacetonate and dissolve it in 30ml of ethanol. Stir for 1 hour to obtain a carbon nanotube growth precursor solution.
[0030] Step 3. Immerse the dried copper foam in the carbon nanotube growth precursor solution for 10 seconds, then remove it and burn it under an alcohol lamp for 10 seconds. Repeat the "immersion and burning" process 30 times to interconnect carbon nanotubes on the copper foam.
[0031] Step 4. Weigh 4.44g of anhydrous calcium chloride powder and dissolve it in 20ml of ethanol to obtain an ethanol solution of calcium chloride;
[0032] Step 5. Place the interconnected carbon nanotube foam copper metal obtained in Step 3 into an ethanol solution of calcium chloride, sonicate for 5 min, and then soak for 30 min; after taking it out, dry it in a vacuum drying oven at 120℃ for 20 min to obtain carbon nanotube-phase change composite heat dissipation material.
[0033] Example 2
[0034] Step 1. Using aluminum foam as a skeleton, the aluminum foam is ultrasonically cleaned in acetone, deionized water, hydrochloric acid and deionized water for 20 minutes in sequence to remove surface oil and impurities, and then placed in a drying oven at 60°C to dry for later use.
[0035] Step 2. Weigh 0.3g of acetylacetone iron and dissolve it in 30ml of ethanol. Stir for 1 hour to obtain a carbon nanotube growth precursor solution.
[0036] Step 3. Immerse the dried aluminum foam in the carbon nanotube growth precursor solution for 10 seconds, then remove it and burn it under an alcohol lamp for 10 seconds. Repeat the "immersion and burning" process 10 times to interconnect carbon nanotubes on the aluminum foam.
[0037] Step 4. Weigh 4.44g of anhydrous calcium chloride powder and dissolve it in 20ml of ethanol to obtain an ethanol solution of calcium chloride;
[0038] Step 5. Place the interconnected carbon nanotube foam obtained in Step 3 into an ethanol solution of calcium chloride, sonicate for 2 min, and then soak for 30 min; after taking it out, dry it in a vacuum drying oven at 120℃ for 20 min to obtain carbon nanotube-phase change composite heat dissipation material.
[0039] Example 3
[0040] Step 1. Using nickel foam as a skeleton, the nickel foam is ultrasonically cleaned in acetone, deionized water, hydrochloric acid and deionized water for 20 minutes in sequence to remove surface oil and impurities, and then placed in a drying oven at 60°C to dry for later use.
[0041] Step 2. Weigh 0.3g of cobalt acetylacetonate and dissolve it in 30ml of ethanol. Stir for 1 hour to obtain a carbon nanotube growth precursor solution.
[0042] Step 3. Immerse the dried nickel foam in the carbon nanotube growth precursor solution for 10 seconds, then remove it and burn it under an alcohol lamp for 20 seconds. Repeat the "immersion and burning" process 10 times to interconnect carbon nanotubes on the nickel foam.
[0043] Step 4. Weigh 4.44g of anhydrous calcium chloride powder and dissolve it in 20ml of ethanol to obtain an ethanol solution of calcium chloride;
[0044] Step 5. Place the interconnected carbon nanotubes obtained in Step 3 into an ethanol solution of calcium chloride, sonicate for 3 min, and then soak for 30 min; after taking it out, dry it in a vacuum drying oven at 120℃ for 20 min to obtain carbon nanotube-phase change composite heat dissipation material.
[0045] Example 4
[0046] Step 1. Using foamed copper metal as a skeleton, the foamed copper metal is ultrasonically cleaned in acetone, deionized water, hydrochloric acid and deionized water for 20 minutes in sequence to remove surface oil and impurities, and then placed in a drying oven at 60℃ to dry for later use.
[0047] Step 2. Weigh 0.3g of cobalt acetylacetonate and dissolve it in 30ml of ethanol. Stir for 1 hour to obtain a carbon nanotube growth precursor solution.
[0048] Step 3. Immerse the dried copper foam in the carbon nanotube growth precursor solution for 20 seconds, then remove it and burn it under an alcohol lamp for 20 seconds. Repeat the "immersion and burning" process 5 times to interconnect carbon nanotubes on the copper foam.
[0049] Step 4. Weigh 4.44g of anhydrous calcium chloride powder and dissolve it in 20ml of ethanol to obtain an ethanol solution of calcium chloride;
[0050] Step 5. Place the interconnected carbon nanotube foam copper metal obtained in Step 3 into an ethanol solution of calcium chloride, sonicate for 4 min, and then soak for 30 min; after taking it out, dry it in a vacuum drying oven at 120℃ for 20 min to obtain carbon nanotube-phase change composite heat dissipation material.
[0051] Example 5
[0052] Step 1. Using foamed copper metal as a skeleton, the foamed copper metal is ultrasonically cleaned in acetone, deionized water, hydrochloric acid and deionized water for 20 minutes in sequence to remove surface oil and impurities, and then placed in a drying oven at 60℃ to dry for later use.
[0053] Step 2. Weigh 0.3g of cobalt acetylacetonate and dissolve it in 30ml of ethanol. Stir for 1 hour to obtain a carbon nanotube growth precursor solution.
[0054] Step 3. Immerse the dried copper foam in the carbon nanotube growth precursor solution for 10 seconds, then remove it and burn it under an alcohol lamp for 30 seconds. Repeat the "immersion and burning" process 10 times to interconnect carbon nanotubes on the copper foam.
[0055] Step 4. Weigh 4.44g of anhydrous lithium chloride powder and dissolve it in 20ml of ethanol to obtain an ethanol solution of lithium chloride;
[0056] Step 5. Place the interconnected carbon nanotube foam copper metal obtained in Step 3 into an ethanol solution of lithium chloride, sonicate for 5 min, and then soak for 30 min; after taking it out, dry it in a vacuum drying oven at 120℃ for 20 min to obtain carbon nanotube-phase change composite heat dissipation material.
[0057] Figure 1 The images shown are scanning electron microscope (SEM) images of the samples prepared in Example 1; where a is an SEM image of the carbon nanotubes prepared in Example 1, and b is an SEM image of the carbon nanotube-phase change composite heat dissipation material prepared in Example 1. Figure 1 As can be seen from a, the carbon nanotubes prepared in Example 1 grow uniformly on copper foam. When these carbon nanotubes are stacked together, they exhibit a forest-like appearance. Compared with pure copper foam, this greatly enhances the specific surface area of the material, which is beneficial for heat conduction. Figure 1 As shown in b, the carbon nanotube structure is covered, and calcium chloride is well loaded on the carbon nanotube / copper foam framework.
[0058] Figure 2 Mapping image of the carbon nanotube-phase change composite heat dissipation material prepared in Example 1; where a is a scanning electron microscope image, b is Ca, c is Cl, and d is the content ratio of each element: from Figure 2 It can be seen that Ca and Cl elements are uniformly distributed on the three-dimensional framework of copper foam, indicating that calcium chloride is well adsorbed on the carbon nanotube / copper foam framework.
[0059] Figure 3 The temperature comparison curves for the cyclic stability test of the carbon nanotube-phase change composite heat dissipation material prepared in Example 1 and carbon nanotubes are shown; the test was conducted at an ambient humidity of 40% and a heating power density of 0.21 W / cm². 2 The following tests were conducted, involving 10 cycles of heating and cooling. Figure 3 It can be seen that the temperature change is stable throughout the process. Compared with carbon nanotube / copper foam, its temperature steadily decreases by 5℃ and there is no significant temperature change with the increase of heating cycle. This indicates that the prepared carbon nanotube-phase change composite heat dissipation material has good heat dissipation stability during long-term cyclic heat dissipation.
[0060] Figure 4 The temperature comparison curves for long-term stability testing of the carbon nanotube-phase change composite heat dissipation material prepared in Example 1 and carbon nanotubes are shown; the temperature was measured at an ambient humidity of 40% and a heating power density of 0.21 W / cm². 2 Under these conditions, a temperature test lasting up to 10 hours was conducted. Figure 4 It can be seen that the equilibrium temperature of carbon nanotube / copper foam is 4.5℃ lower than that of carbon nanotube-phase change composite heat dissipation material, indicating that the prepared carbon nanotube-phase change composite heat dissipation material has high thermal stability.
Claims
1. A method for preparing a foamed metal-based atmospheric water-absorbing passive heat dissipation material, characterized in that, Includes the following steps: Step 1. Using foamed metal as a framework, the foamed metal is ultrasonically cleaned and dried; Step 2. Prepare a carbon nanotube growth precursor solution with a concentration of 0.1 g / ml to 0.3 g / ml; the solute of the carbon nanotube growth precursor solution is one or more of cobalt acetylacetone, iron acetylacetone, and silver acetylacetone, and the solvent is ethanol; Step 3. Immerse the dried foam metal in the carbon nanotube growth precursor solution for 10-20 seconds, then remove it and burn it under an alcohol lamp for 10-30 seconds. Repeat the "immersion and burning" process 5-30 times to form interconnected carbon nanotubes on the foam metal framework. Step 4. Prepare a desiccant solution with a concentration of 0.1~2 mol / L; the solute of the desiccant solution is one or more of lithium chloride, calcium chloride, and lithium bromide, and the solvent is water or ethanol; Step 5. Place the interconnected carbon nanotube foam metal obtained in Step 3 into a desiccant solution, sonicate for 1-5 minutes, and then soak for 30 minutes; after removal, dry to obtain a foam metal-based atmospheric water-absorbing passive heat dissipation material.
2. The preparation method of the foamed metal-based atmospheric water-absorbing passive heat dissipation material according to claim 1, characterized in that, In step 1, the foamed metal is ultrasonically cleaned in acetone, deionized water, hydrochloric acid, and deionized water for 20 minutes in sequence, and then placed in a drying oven at 60°C to dry for later use.
3. The preparation method of the foamed metal-based atmospheric water-absorbing passive heat dissipation material according to claim 1, characterized in that, The drying process described in step 5 involves drying in a vacuum drying oven at 100–150°C for 10–30 minutes.