Foam metal-based atmosphere water absorption passive heat dissipation material and preparation method thereof

Abstract

The invention discloses a foam metal-based atmosphere water absorption passive heat dissipation material and a preparation method, and relates to an efficient passive heat dissipation material. Foam metal is adopted as a framework, and a layer of interconnected carbon nanotubes are grown on the surface of the framework through a flame method. By utilizing the interconnection structure of the carbon nanotubes, heat can be quickly and uniformly conducted to the heat dissipation surface, and the radiation heat dissipation capability is effectively improved by virtue of the high surface emissivity characteristic of the carbon nanotubes. On the basis, the moisture absorbent material is anchored to the surface of the carbon nano tube, and the atmospheric water absorption passive heat dissipation material with remarkable heat dissipation performance is prepared.

Description

Technical Field

[0001] The invention relates to a high-efficiency passive heat dissipation material, in particular to a foam metal-based atmospheric water absorption passive heat dissipation material and a preparation method thereof. Background Art

[0002] With the rapid development of modern electronic technology, electronic devices are playing an increasingly important role in the fields of industry, aerospace, and portable electronic devices. High integration, lightweight, and high power of electronic devices have become a development trend. However, with the continuous improvement of integration, its feature size has gradually decreased, and the power density has increased rapidly, resulting in a significant increase in system temperature. Studies have shown that about 55% of the failure causes of electronic devices are related to high temperature. Therefore, how to effectively manage heat to ensure that electronic devices operate within the optimal operating temperature range has become a key issue that needs to be solved urgently.

[0003] Passive heat dissipation technology is a heat dissipation method that does not require additional energy to drive it. It is widely used in electronic devices, mechanical equipment, and construction. By optimizing materials, structural design, and natural heat exchange processes, passive heat dissipation technology can effectively improve the efficiency of heat transfer, reduce the operating temperature of equipment, and extend the service life. Its main principles include heat transfer mechanisms such as thermal conduction, convection, and radiation, and performance is improved through the optimization of the material's high thermal conductivity, surface properties, and geometric structure. 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, the research direction of passive heat dissipation technology has gradually tilted 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, metal organic frameworks (MOF), etc., have attracted widespread attention due to their excellent thermal conductivity and lightweight properties. In addition, multi-material composite heat sinks that combine heat dissipation with other functions have also become an important means to improve 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 reflect the diversified development trend of passive heat dissipation technology.

[0005] However, the current passive heat dissipation technology still faces some urgent problems. On the one hand, the thermal conductivity of existing materials has not yet reached the ideal state, especially in high power density and complex thermal environment, its heat dissipation capacity may be insufficient. On the other hand, the interface thermal resistance control and long-term reliability of multi-material composite heat sinks are still key technical bottlenecks. In addition, the large-scale preparation of new heat dissipation materials and devices with high consistency and low cost has also restricted the practical application of the technology. Therefore, future research needs to further break through new material development, structural design optimization and industrial manufacturing technology to promote the comprehensive development of passive heat dissipation technology. Summary of the invention

[0006] The purpose of the present invention is to propose a foam metal-based atmospheric water-absorbing passive heat dissipation material and a preparation method thereof in view of the problems existing in the background technology. The present invention adopts foam metal as a skeleton, and grows a layer of interconnected carbon nanotubes on the surface of the skeleton by a flame method. Utilizing the interconnected structure of carbon nanotubes, heat can be quickly and evenly conducted to the heat dissipation surface, and the radiation heat dissipation capacity can be effectively improved by virtue of its high surface emissivity characteristics. On this basis, a desiccant is introduced into the carbon nanotube system to prepare a foam metal-based atmospheric water-absorbing passive heat dissipation material with significant heat dissipation performance. The foam metal-based atmospheric water-absorbing passive heat dissipation material can absorb water molecules from the atmospheric environment by itself, and anchor the water molecules in the material body through the siphon effect. When used for device heat dissipation, water molecules are transformed from solid / liquid to gaseous during the temperature increase process, and the phase change process will absorb a large amount of heat, thereby effectively suppressing the increase in the temperature of the heat dissipated device.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0008] A foam metal-based atmospheric water absorption passive heat dissipation material and a preparation method thereof, comprising the following steps:

[0009] Step 1. Using foam metal as a skeleton, ultrasonically clean the foam metal in acetone, deionized water, hydrochloric acid, and deionized water for 20 minutes in sequence to remove surface oil and impurities, and then put it into a drying oven at 60° C. for standby 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. Soak the metal foam after the drying treatment in step 1 in a carbon nanotube growth precursor solution for 10 to 20 seconds, take it out and burn it under an alcohol lamp for 10 to 30 seconds, repeat the "soaking and burning" process 5 to 30 times to form interconnected carbon nanotubes on the metal foam skeleton;

[0012] Step 4. Prepare a moisture absorbent solution with a concentration of 0.1 to 2 mol / L;

[0013] Step 5. Immerse the carbon nanotube-loaded metal foam obtained in step 3 in a desiccant solution, perform ultrasonic treatment for 1 to 5 minutes, and then soak for 30 minutes; after taking out, dry it in a vacuum drying oven at 100 to 150° C. for 10 to 30 minutes to obtain a metal foam-based atmospheric water absorption passive heat dissipation material.

[0014] Furthermore, the solute of the carbon nanotube growth precursor solution in step 2 is one or more of cobalt acetylacetonate, iron acetylacetonate, and silver acetylacetonate, and the solvent is ethanol.

[0015] Furthermore, the solute of the desiccant solution 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 present invention has the following beneficial effects:

[0017] 1. The present invention uses foam metal as a skeleton and forms interconnected carbon nanotubes on the skeleton, which can quickly and evenly conduct heat to the heat dissipation surface, and effectively improve the radiation heat dissipation capacity by virtue of its high surface emissivity characteristics.

[0018] 2. The present invention adopts a flame method to prepare carbon nanotubes on foam metal, which has a simple process, low cost, and has the characteristics of high thermal conductivity, high emissivity, etc., and can quickly and evenly conduct heat to the heat dissipation surface for heat dissipation.

[0019] 3. In the process of preparing carbon nanotubes, the present invention adjusts the concentration of the carbon nanotube solution and the number of immersion-combustion times so that more carbon nanotubes are loaded on 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. When loading the desiccant material, the present invention adopts a method of ultrasonic treatment followed by immersion. The ultrasonic treatment can effectively reduce the agglomeration of the desiccant material, promote its better loading on the foam metal skeleton, further increase its specific surface area, and facilitate phase change materials such as calcium chloride to absorb moisture in the air. The evaporation phase change of water can take away a large amount of heat, further improving the heat dissipation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a scanning electron microscope image of the sample prepared in Example 1; wherein a is a scanning electron microscope image of the carbon nanotube prepared in Example 1, and b is a scanning electron microscope image of the foam metal-based atmospheric water absorption passive heat dissipation material prepared in Example 1;

[0022] Figure 2 This is the element distribution diagram of the copper-based atmospheric water absorption passive heat dissipation material prepared in Example 1; wherein 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 The temperature comparison curve of the cyclic stability test of the copper-based atmospheric water absorption passive heat dissipation material prepared in Example 1 and the carbon nanotubes;

[0024] Figure 4 This is a temperature comparison curve of a long-term stable test of the copper-based atmospheric water absorption passive heat dissipation material prepared in Example 1 and carbon nanotubes. DETAILED DESCRIPTION

[0025] The above scheme is further described below in conjunction with specific embodiments, and preferred embodiments of the present invention are described in detail as follows:

[0026] In the examples, unless otherwise specified, all raw materials are commercially available and no further purification is required.

[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, and then placed in a drying oven at 60° C. for standby use;

[0029] Step 2. Weigh 0.3 g of cobalt acetylacetonate and dissolve it in 30 ml of ethanol, and stir for 1 hour to obtain a carbon nanotube growth precursor solution;

[0030] Step 3. Soak the dried copper foam in a carbon nanotube growth precursor solution for 10 seconds, take it out and burn it under an alcohol lamp for 10 seconds, repeat the "soaking and burning" process 30 times to interconnect carbon nanotubes on the copper foam;

[0031] Step 4. Weigh 4.44 g of anhydrous calcium chloride powder and dissolve it in 20 ml of ethanol to obtain an ethanol solution of calcium chloride;

[0032] Step 5. Place the interconnected carbon nanotube copper foam metal obtained in step 3 in an ethanol solution of calcium chloride, ultrasonically treat for 5 minutes, and then soak for 30 minutes; after taking it out, dry it in a vacuum drying oven at 120°C for 20 minutes to obtain a carbon nanotube-phase change composite heat dissipation material.

[0033] Example 2

[0034] Step 1. Using aluminum foam as a skeleton, ultrasonically clean the aluminum foam in acetone, deionized water, hydrochloric acid, and deionized water for 20 minutes in sequence to remove surface oil and impurities, and then put it into a drying oven to dry at 60°C for standby use;

[0035] Step 2. Weigh 0.3 g of ferric acetylacetonate and dissolve it in 30 ml of ethanol, and stir for 1 hour to obtain a carbon nanotube growth precursor solution;

[0036] Step 3. Soak the dried aluminum foam in a carbon nanotube growth precursor solution for 10 seconds, take it out and burn it under an alcohol lamp for 10 seconds, repeat the "soaking and burning" process 10 times to interconnect carbon nanotubes on the aluminum foam;

[0037] Step 4. Weigh 4.44 g of anhydrous calcium chloride powder and dissolve it in 20 ml of ethanol to obtain an ethanol solution of calcium chloride;

[0038] Step 5. Place the interconnected carbon nanotube aluminum foam obtained in step 3 in an ethanol solution of calcium chloride, ultrasonically treat for 2 minutes, and then soak for 30 minutes; after taking it out, dry it in a vacuum drying oven at 120° C. for 20 minutes to obtain a 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. for standby use;

[0041] Step 2. Weigh 0.3 g of cobalt acetylacetonate and dissolve it in 30 ml of ethanol, and stir for 1 hour to obtain a carbon nanotube growth precursor solution;

[0042] Step 3. Soak the dried nickel foam in a carbon nanotube growth precursor solution for 10 seconds, take it out and burn it under an alcohol lamp for 20 seconds, repeat the "soaking and burning" process 10 times to interconnect carbon nanotubes on the nickel foam;

[0043] Step 4. Weigh 4.44 g of anhydrous calcium chloride powder and dissolve it in 20 ml of ethanol to obtain an ethanol solution of calcium chloride;

[0044] Step 5. Place the interconnected carbon nanotube nickel foam obtained in step 3 in an ethanol solution of calcium chloride, ultrasonically treat for 3 minutes, and then soak for 30 minutes; after taking out, dry it in a vacuum drying oven at 120° C. for 20 minutes to obtain a carbon nanotube-phase change composite heat dissipation material.

[0045] Example 4

[0046] Step 1. Using foam copper metal as a skeleton, ultrasonically cleaning the foam copper metal in acetone, deionized water, hydrochloric acid, and deionized water for 20 minutes in sequence to remove surface oil and impurities, and then drying it in a drying oven at 60° C. for standby use;

[0047] Step 2. Weigh 0.3 g of cobalt acetylacetonate and dissolve it in 30 ml of ethanol, and stir for 1 hour to obtain a carbon nanotube growth precursor solution;

[0048] Step 3. Soak the dried copper foam in a carbon nanotube growth precursor solution for 20 seconds, take it out and burn it under an alcohol lamp for 20 seconds, repeat the "soaking and burning" process 5 times to interconnect carbon nanotubes on the copper foam;

[0049] Step 4. Weigh 4.44 g of anhydrous calcium chloride powder and dissolve it in 20 ml of ethanol to obtain an ethanol solution of calcium chloride;

[0050] Step 5. Place the interconnected carbon nanotube copper foam metal obtained in step 3 in an ethanol solution of calcium chloride, ultrasonically treat for 4 minutes, and then soak for 30 minutes; after taking it out, dry it in a vacuum drying oven at 120°C for 20 minutes to obtain a carbon nanotube-phase change composite heat dissipation material.

[0051] Example 5

[0052] Step 1. Using foam copper metal as a skeleton, ultrasonically cleaning the foam copper metal in acetone, deionized water, hydrochloric acid, and deionized water for 20 minutes in sequence to remove surface oil and impurities, and then drying it in a drying oven at 60° C. for standby use;

[0053] Step 2. Weigh 0.3 g of cobalt acetylacetonate and dissolve it in 30 ml of ethanol, and stir for 1 hour to obtain a carbon nanotube growth precursor solution;

[0054] Step 3. Soak the dried copper foam in a carbon nanotube growth precursor solution for 10 seconds, take it out and burn it under an alcohol lamp for 30 seconds, repeat the "soaking and burning" process 10 times to interconnect carbon nanotubes on the copper foam;

[0055] Step 4. Weigh 4.44 g of anhydrous lithium chloride powder and dissolve it in 20 ml of ethanol to obtain an ethanol solution of lithium chloride;

[0056] Step 5. Place the interconnected carbon nanotubes obtained in step 3 into an ethanol solution of lithium chloride, ultrasonically treat for 5 minutes, and then soak for 30 minutes; after taking it out, dry it in a vacuum drying oven at 120° C. for 20 minutes to obtain a carbon nanotube-phase change composite heat dissipation material.

[0057] Figure 1 is a scanning electron microscope image of the sample prepared in Example 1; wherein a is a scanning electron microscope image of the carbon nanotube prepared in Example 1, and b is a scanning electron microscope image of the carbon nanotube-phase change composite heat dissipation material prepared in Example 1. Figure 1 It can be seen from a that the carbon nanotubes prepared in Example 1 grow uniformly on the copper foam. When these carbon nanotubes are piled together, they present a forest shape. Compared with pure copper foam, this greatly enhances the specific surface area of ​​the material, which is beneficial to the conduction of heat. Figure 1 b It can be seen that the carbon nanotube structure is covered and the calcium chloride is well loaded on the carbon nanotube / foam copper skeleton.

[0058] Figure 2 Mapping diagram of the carbon nanotube-phase change composite heat dissipation material prepared in Example 1; wherein a is a scanning electron microscope image, b is Ca, c is Cl, and d is the content ratio of each element: Figure 2 It can be seen that Ca and Cl elements are evenly 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 curve of the cyclic stability test of the carbon nanotube-phase change composite heat dissipation material prepared in Example 1 and the carbon nanotube; when the ambient humidity is 40% and the heating power density is 0.21W / cm 2 The test was conducted under 10 heating and cooling cycles. Figure 3 It can be seen that the temperature change is stable during the whole process. Compared with carbon nanotubes / foam copper, its temperature is stably reduced at 5°C, and there is no obvious temperature change with the increase of heating cycle, indicating 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 curve of the carbon nanotube-phase change composite heat dissipation material prepared in Example 1 and the carbon nanotubes in the long-term stable test; the ambient humidity is 40% and the heating power density is 0.21W / cm 2 The temperature test was carried out for up to 10 hours. Figure 4 It can be seen that the equilibrium temperature of carbon nanotube / foam copper is reduced by 4.5°C compared with carbon nanotube-phase change composite heat dissipation material, indicating that the prepared carbon nanotube-phase change composite heat dissipation material has higher thermal stability.

Claims

1. A foam metal-based atmospheric water absorption passive heat dissipation material, characterized in that: The foam metal-based atmospheric water absorption passive heat dissipation material uses foam metal as a skeleton, carbon nanotubes are evenly dispersed and anchored on the surface of the foam metal skeleton, and a desiccant is evenly riveted to the surface of the carbon nanotubes; the foam metal and the carbon nanotubes provide a rapid heat transmission channel, and the desiccant forms an adsorption / desorption site for atmospheric water vapor.

2. The foam metal-based atmospheric water absorption passive heat dissipation material according to claim 1, characterized in that: The foam metal is foam copper, foam nickel, foam aluminum, foam zinc-copper alloy or foam nickel-copper alloy.

3. A method for preparing a foam metal-based atmospheric water absorption passive heat dissipation material, characterized in that: The following steps are involved: Step 1. Use foam metal as a skeleton, ultrasonically clean the foam metal, and dry it; Step 2. Prepare a carbon nanotube growth precursor solution with a concentration of 0.1 g / ml to 0.3 g / ml; Step 3. Soak the dried foam metal in a carbon nanotube growth precursor solution for 10 to 20 seconds, take it out and burn it under an alcohol lamp for 10 to 30 seconds, repeat the "soaking and burning" process 5 to 30 times to form interconnected carbon nanotubes on the foam metal skeleton; Step 4. Prepare a moisture absorbent solution with a concentration of 0.1 to 2 mol / L; Step 5. Place the interconnected carbon nanotube metal foam obtained in step 3 in a desiccant solution, perform ultrasonic treatment for 1 to 5 minutes, and then soak for 30 minutes; take it out and dry it to obtain a metal foam-based atmospheric water absorption passive heat dissipation material.

4. The method for preparing the foamed metal-based atmospheric water absorption passive heat dissipation material according to claim 3, 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 to dry at 60° C. for later use.

5. The method for preparing the foamed metal-based atmospheric water absorption passive heat dissipation material according to claim 3, characterized in that: In step 2, the solute of the carbon nanotube growth precursor solution is one or more of cobalt acetylacetonate, iron acetylacetonate, and silver acetylacetonate, and the solvent is ethanol.

6. The method for preparing the foamed metal-based atmospheric water absorption passive heat dissipation material according to claim 3, characterized in that: The solute of the desiccant solution in step 4 is one or more of lithium chloride, calcium chloride, and lithium bromide, and the solvent is water or ethanol.

7. The method for preparing the foamed metal-based atmospheric water absorption passive heat dissipation material according to claim 3, characterized in that: The drying in step 5 is carried out in a vacuum drying oven at 100-150° C. for 10-30 min.

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