Method for preparing three-dimensional graphite uniformly reinforced copper-based multi-channel heat-conducting interface material

Abstract

The application relates to a method for uniformly enhancing a three-dimensional graphite copper-based multi-channel heat-conducting interface material, and relates to a method for enhancing the heat-conducting performance of an interface material. The application aims at solving the problems that the wetting between existing graphite and metal is poor, the composite material is made by using a powder mixing sintering mode, the carbon material is prone to agglomeration, the material performance uniformity is poor, and the heat-conducting interface material cannot realize the uniform and reliable combination of copper and carbon. The method comprises the following steps: one, loading a carbon source by using a hydrothermal method; and two, annealing at high temperature. The application is used for uniformly enhancing a three-dimensional graphite copper-based multi-channel heat-conducting interface material.

Description

Technical Field

[0001] This invention relates to a method for enhancing the thermal conductivity of interface materials. Background Technology

[0002] The use of an intermediate layer is crucial in brazing, especially in high-power and high-density heat flux applications, where it enhances thermal conductivity and facilitates heat dissipation by connecting the heat source and heat sink, preventing excessive heat buildup and device damage. However, the brazing filler metal is prone to uneven distribution between the intermediate layer and the base material, leading to weak connections in localized areas and affecting the overall strength and reliability of the joint. The intermediate layer material can also deteriorate due to thermal cycling, corrosion, or other environmental factors, reducing the durability and reliability of the joint. Graphite's excellent thermal conductivity and lubrication properties, combined with the lightweight and mechanical strength of copper foam, make it outstanding in thermal management and stress dispersion. Graphite's high thermal conductivity and low coefficient of thermal expansion effectively reduce thermal stress and deformation, while the porous structure of copper foam provides greater space for brazing filler metal, enhancing the strength and toughness of the joint, making it suitable for high-performance and high-reliability thermal management applications. However, graphite has poor wettability with metals, and the interface connection is mainly mechanical. Current research mostly uses powder mixing and sintering to create composite materials, but the tendency of carbon materials to agglomerate results in poor material uniformity. Therefore, there is an urgent need to develop a thermally conductive interface material with uniform and reliable copper-carbon bonding for use as an intermediate layer material in the brazing process. Summary of the Invention

[0003] This invention aims to address the problem that existing graphite-metal composite materials, which have poor wettability and are produced by powder mixing and sintering, suffer from poor uniformity of material properties due to the easy agglomeration of carbon materials, thus failing to achieve a uniform and reliable thermal interface material for copper and carbon bonding. Therefore, this invention provides a method for a three-dimensional graphite-uniformly reinforced copper-based multi-channel thermal interface material.

[0004] A method for a three-dimensional graphite-based uniformly reinforced copper-based multichannel thermally conductive interface material is carried out according to the following steps:

[0005] I. Using hydrothermal methods to load carbon sources:

[0006] ① Dissolve glucose in deionized water and stir until homogeneous at room temperature to obtain a glucose solution;

[0007] ②Immerse copper foam in glucose solution and react under high temperature and pressure;

[0008] ③ After the reaction is complete, cool to room temperature to obtain copper foam supported on a carbon source;

[0009] II. Annealing at high temperature:

[0010] Under protective gas and at a temperature of 550℃~750℃, copper foam loaded with carbon source is kept at a temperature of 1h~2h, and finally cooled in the furnace and taken out to obtain a three-dimensional graphite-reinforced copper-based multi-channel thermal interface material.

[0011] The beneficial effects of this invention are:

[0012] 1. This invention improves the uniformity of graphite and copper-based material distribution. After high-temperature, high-pressure hydrothermal treatment, the raw glucose undergoes a caramelization reaction. The 5-hydroxymethylfurfural in the product is uniformly loaded onto the three-dimensional network framework of copper foam. Then, in step two, high-temperature annealing dehydration leaves a small amount of residual oxygen-containing functional groups to aid interface wetting, and there is no large accumulation of amorphous carbon. Pre-loading with 5-hydroxymethylfurfural avoids direct bonding between carbon materials and copper foam, solving the problem of uneven local distribution.

[0013] 2. This invention ranks among the top in thermal conductivity in the thermal interface material industry. Using foamed metal as a framework and supplemented with graphite, the thermal conductivity is significantly improved compared to the original foamed copper under the coupling effect of phonon and electron dual thermal conduction channels, reaching 20W / (m·K)~30W / (m·K). Compared to the original single matrix, phonon scattering at the interface is effectively suppressed, and the heat transfer rate is much greater than that of traditional thermal interface materials.

[0014] 3. This invention uses glucose as a carbon source, reducing production costs and showing great application potential. Glucose, as one of the most widely distributed monosaccharides in nature, is easy to obtain and has a substantial yield, as well as good biocompatibility, making carbon-copper composite materials using glucose as a carbon source potentially valuable in the biomedical field. The combination of graphite and copper can endow the composite material with different physical and chemical properties, such as high electrical conductivity and high catalytic activity.

[0015] Instruction manual illustrations

[0016] Figure 1 Scanning electron microscope image of graphite on the three-dimensional graphite-reinforced copper-based multichannel thermally conductive interface material prepared in Example 1;

[0017] Figure 2 The image shows the surface-enhanced Raman curve of graphite on the three-dimensional graphite-reinforced copper-based multichannel thermally conductive interface material prepared in Example 1.

[0018] Figure 3 A digital photograph of the three-dimensional graphite-reinforced copper-based multichannel thermally conductive interface material prepared in Example 1;

[0019] Figure 4 To compare the enhanced Raman curves of the products on the surface of copper foam under the experimental conditions. Detailed Implementation

[0020] Specific Implementation Method 1: This implementation method discloses a method for producing a three-dimensional graphite-based uniformly reinforced copper-based multi-channel thermally conductive interface material, which is carried out according to the following steps:

[0021] I. Using hydrothermal methods to load carbon sources:

[0022] ① Dissolve glucose in deionized water and stir until homogeneous at room temperature to obtain a glucose solution;

[0023] ②Immerse copper foam in glucose solution and react under high temperature and pressure;

[0024] ③ After the reaction is complete, cool to room temperature to obtain copper foam supported on a carbon source;

[0025] II. Annealing at high temperature:

[0026] Under protective gas and at a temperature of 550℃~750℃, copper foam loaded with carbon source is kept at a temperature of 1h~2h, and finally cooled in the furnace and taken out to obtain a three-dimensional graphite-reinforced copper-based multi-channel thermal interface material.

[0027] The beneficial effects of this embodiment are:

[0028] 1. This embodiment improves the uniformity of graphite and copper-based material distribution. After the glucose solution is subjected to high-temperature and high-pressure hydrothermal treatment, the raw glucose undergoes a caramelization reaction. The 5-hydroxymethylfurfural in the product is uniformly loaded onto the three-dimensional network framework of the copper foam. Then, in step two, dehydration under high-temperature annealing leaves a small amount of residual oxygen-containing functional groups to help wet the interface, and there is no large accumulation of amorphous carbon. By pre-loading 5-hydroxymethylfurfural, direct bonding between carbon materials and copper foam is avoided, solving the problem of uneven local distribution.

[0029] 2. This embodiment boasts leading thermal conductivity in the thermal interface material industry. Using foamed metal as a framework and supplemented with graphite, the thermal conductivity is significantly improved compared to the original foamed copper under the coupling effect of phonon and electron dual thermal conduction channels, reaching 20 W / (m·K) to 30 W / (m·K). Compared to the original single matrix, phonon scattering at the interface is effectively suppressed, and the heat transfer rate is much greater than that of traditional thermal interface materials.

[0030] 3. This implementation method uses glucose as a carbon source, reducing production costs and showing significant application potential. Glucose, as one of the most widely distributed monosaccharides in nature, is readily available and produced in substantial quantities, exhibiting good biocompatibility. This makes carbon-copper composite materials using glucose as a carbon source potentially valuable in the biomedical field. The combination of graphite and copper can endow the composite material with different physical and chemical properties, such as high electrical conductivity and high catalytic activity.

[0031] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the concentration of the glucose solution mentioned in step one ① is 0.1 mol / L to 1 mol / L. Everything else is the same as in Specific Implementation Method One.

[0032] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that the copper foam described in step one, ②, has a porosity (PPI) of 90-100 per inch. Everything else is the same as in Specific Implementation Method One or Two.

[0033] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that the high-temperature and high-pressure reaction described in step one, ②, is specifically carried out at a reaction temperature of 110℃~180℃ and a pressure of 3MPa~10MPa for 3h~6h. Everything else is the same as in Specific Implementation Methods One to Three.

[0034] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that the high-temperature and high-pressure reaction described in step one, step two, is specifically carried out at a reaction temperature of 110℃ to 150℃ and a pressure of 3MPa to 5MPa for 6 hours. Everything else is the same as in Specific Implementation Methods One to Four.

[0035] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that the protective gas mentioned in step two is one or a mixture of argon, hydrogen, and nitrogen. Everything else is the same as in Specific Implementation Methods One to Five.

[0036] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One to Six in that the flow rate of the protective gas in step two is 20 sccm to 30 sccm. Everything else is the same as in Specific Implementation Methods One to Six.

[0037] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that: in step two, the copper foam loaded with the carbon source is heated to 550°C to 750°C at a heating rate of 5°C / min to 15°C / min. Everything else is the same as in Specific Implementation Methods One to Seven.

[0038] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that: in step two, the carbon-source-loaded copper foam is heated to 600℃ to 750℃ at a heating rate of 5℃ / min to 10℃ / min. Everything else is the same as in Specific Implementation Methods One to Eight.

[0039] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Methods One to Nine in that: in step two, the copper foam loaded with the carbon source is kept at a protective gas temperature of 600℃ to 750℃ for 1 to 2 hours. Everything else is the same as in Specific Implementation Methods One to Nine.

[0040] The beneficial effects of the present invention are verified using the following embodiments:

[0041] Example 1:

[0042] A method for a three-dimensional graphite-based uniformly reinforced copper-based multichannel thermally conductive interface material is carried out according to the following steps:

[0043] I. Using hydrothermal methods to load carbon sources:

[0044] ① Dissolve glucose in deionized water and stir until homogeneous at room temperature to obtain a glucose solution;

[0045] ②The copper foam was immersed in a glucose solution and reacted for 6 hours at a reaction temperature of 110℃ and a pressure of 5MPa.

[0046] ③ After the reaction is complete, cool to room temperature to obtain copper foam supported on a carbon source;

[0047] II. Annealing at high temperature:

[0048] Under an argon flow rate of 20 sccm, the carbon-supported copper foam was heated to 750℃ at a heating rate of 5℃ / min. The carbon-supported copper foam was then held at 750℃ for 1 hour and finally cooled in the furnace before being removed to obtain a three-dimensional graphite-reinforced copper-based multichannel thermal interface material.

[0049] The concentration of the glucose solution mentioned in step 1① is 0.1 mol / L.

[0050] The copper foam described in step 1② has a porosity per inch (PPI) of 90.

[0051] Step 1② The 3×3cm foam copper 2 .

[0052] Figure 1 The image shows a scanning electron microscope (SEM) image of graphite on the three-dimensional graphite-reinforced copper-based multichannel thermal interface material prepared in Example 1. As can be seen from the image, the graphite is uniformly distributed on the foamed copper skeleton to form a three-dimensional structure. There is no large amount of amorphous carbon aggregation. The small amount of exposed part is due to the excessive curvature of the foamed copper surface, which causes the graphite to peel off.

[0053] Figure 2 The figure shows the surface-enhanced Raman curve of graphite on the three-dimensional graphite-reinforced copper-based multichannel thermally conductive interface material prepared in Example 1; as can be seen from the figure, I D / I G With a graphite defect count of 0.7, the graphite defect level is low, which plays a key role in enhancing the thermal conductivity of the foamed copper matrix.

[0054] Figure 3This is a digital photograph of the three-dimensional graphite-reinforced copper-based multichannel thermal interface material prepared in Example 1. Due to the strong absorption of photons by graphite, this example exhibits a distinctly black appearance, with the graphite layer adhering well to the substrate and being evenly distributed.

[0055] The thermal conductivity of the three-dimensional graphite-reinforced copper-based multichannel thermal interface material prepared in Example 1 was measured to be 23.8 W / (m·K) using a laser thermal conductivity meter (LFA467).

[0056] Comparative Experiment: This comparative experiment differs from Example 1 in that step 1② is skipped; the copper foam is immersed in glucose solution and left to stand at room temperature for 6 hours. Everything else is the same as in Example 1.

[0057] Figure 4 To compare the enhanced Raman curves of the products on the surface of copper foam under the experiment; as can be seen from the figure, there is no obvious carbon peak, which means that the graphite precursor 5-hydroxymethylfurfural generated by the hydrothermal glucose method is very important for the generation of three-dimensional graphite.

Claims

1. A method for using three-dimensional graphite uniformly reinforced copper-based multi-channel thermally conductive interface materials, characterized in that... It is done in the following steps: I. Using hydrothermal methods to load carbon sources: ① Dissolve glucose in deionized water and stir until homogeneous at room temperature to obtain a glucose solution; The concentration of the glucose solution is 0.1 mol / L; ② The copper foam was immersed in a glucose solution and reacted for 6 hours at a reaction temperature of 110℃ and a pressure of 5MPa. The glucose underwent a caramelization reaction, and 5-hydroxymethylfurfural in the product was uniformly loaded on the three-dimensional network framework of the copper foam. The copper foam has a porosity per inch (PPI) of 90. ③ After the reaction is complete, cool to room temperature to obtain copper foam supported on a carbon source; II. Annealing at high temperature: Under a protective gas, the carbon-loaded copper foam was heated to 750°C at a heating rate of 5°C / min. Then, under a protective gas and a temperature of 750°C, the carbon-loaded copper foam was kept at this temperature for 1 hour. Finally, it was cooled in the furnace and removed to obtain a three-dimensional graphite-reinforced copper-based multi-channel thermally conductive interface material. The flow rate of the protective gas is 20 sccm; The thermal conductivity of the three-dimensional graphite-reinforced copper-based multichannel thermal interface material is 23.8 W / (m·K).

2. The method for a three-dimensional graphite uniformly reinforced copper-based multi-channel thermally conductive interface material according to claim 1, characterized in that... The protective gas mentioned in step two is one or a mixture of argon, hydrogen, and nitrogen.

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