High-thermal-conductivity liquid metal thermal interface composite material and preparation method thereof

Abstract

The invention belongs to the technical field of heat conduction materials, and discloses a high-heat-conductivity liquid metal thermal interface composite material and a preparation method thereof.The composite material comprises, by weight, 60-90 parts of gallium, 10-25 parts of indium, 0-20 parts of tin, 1-3 parts of nickel-coated carbon and 0.01-1 part of silicon carbide; the nickel-coated carbon and the silicon carbide are compounded into the liquid metal gallium indium tin, so that the high-thermal-conductivity liquid metal thermal interface composite material can be obtained; wherein the nickel-coated carbon is added, so that the heat-conducting property of the gallium-indium-tin liquid metal can be remarkably improved, because on one hand, a nickel layer is used as a thermal bridge for connecting a carbon material and the liquid metal, the interface thermal resistance can be reduced, the wettability of nickel and gallium-indium-tin is good, and on the other hand, the viscosity of gallium-indium-tin can be improved to a certain extent; therefore, random flowing of the liquid metal is inhibited; and silicon carbide does not react with gallium indium tin at normal temperature, so that the internal friction resistance of the liquid metal can be increased, and the silicon carbide can be embedded into the interface of the liquid metal and the substrate, thereby improving the affinity of the material.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of heat-conducting materials, and particularly relates to a high-heat-conducting liquid metal thermal interface composite material and a preparation method thereof. BACKGROUND

[0002] In recent years, with the gradual increase of the power consumption of electronic products, the thermal management of electronic devices has become a key factor of the quality of electronic products. The commonly used method is to remove excessive heat by using a heat sink to achieve thermal management. However, due to the poor contact between the electronic chip and the heat sink, the thermal resistance between them is large, thereby leading to the decrease of the thermal diffusion coefficient of the electronic product. In order to solve this problem, some thermal interface materials can be filled in the gap between the electronic chip and the heat sink to improve the heat dissipation performance. Traditional thermal interface materials include silicone grease, silicone pad and phase change material, which are mainly based on high molecular materials, and the thermal conductivity of these traditional thermal interface materials is improved by adding heat-conducting fillers. However, the highest thermal conductivity can only be increased to 10 W / (m·K), and their cooling capacity still cannot meet the needs of high-performance electronic components.

[0003] The liquid metal thermal interface composite material is a high-end interface material with high thermal conductivity and high temperature resistance. The common liquid metal thermal interface composite material is mainly gallium-based liquid metal material, which has the characteristics of high thermal conductivity and simple production, and can meet different heat transfer requirements. However, due to the large surface tension and good flowability of the liquid metal, there are problems such as overflow and poor affinity between the electronic chip and the heat sink in the application process, which seriously restricts the application and development of the liquid metal as a thermal interface material.

[0004] The information disclosed in this BACKGROUND section is only intended to increase an understanding of the general background of the application and should not be construed as a recognition of the information being the prior art in any form. SUMMARY

[0005] The present application aims to provide a high-heat-conducting liquid metal thermal interface composite material and a preparation method thereof, so as to overcome the defects in the prior art.

[0006] In order to achieve the above-mentioned purpose, the present application provides a high-heat-conducting liquid metal thermal interface composite material, which comprises the following raw materials by weight: 60-90 parts of gallium, 10-25 parts of indium, 0-20 parts of tin, 1-3 parts of nickel-coated carbon and 0.01-1 part of silicon carbide.

[0007] Further, as a preferred embodiment, the content of nickel in the nickel-coated carbon is 40-50%.

[0008] Further, as a preferred embodiment, the particle size of the silicon carbide is 30 nm-1 μm.

[0009] Further, as more preferably, the weight ratio of gallium, indium and tin is 68.5:21.5:10, and the weight ratio of gallium, indium, tin, nickel-coated carbon and silicon carbide is 98.5:1:0.5.

[0010] The application also provides a method for preparing the high-thermal-conductivity liquid metal thermal interface composite material, comprising the following steps: S1: preparing solid gallium, solid indium, solid tin, NiSO4·6H2O, NaH2PO2·H2O, sodium citrate, carbon powder and silicon carbide as raw materials, and placing the solid gallium into an oven and keeping it at 80-100℃; S2: taking out the melted liquid gallium, weighing the liquid gallium, solid indium and solid tin according to the mass ratio, and placing them into a quartz crucible, and placing the crucible into the oven and keeping it at 240-260℃, and mixing the gallium, indium and tin materials uniformly by using a stirring paddle during the keeping process, and naturally cooling to room temperature to obtain a gallium, indium and tin liquid alloy; S3: placing the carbon powder into a 5% HNO3 solution and performing ultrasonic activation treatment, mixing NiSO4·6H2O, NaH2PO2·H2O and sodium citrate to prepare a plating solution, and adjusting the PH of the plating solution to alkaline by using ammonia; S4: adding the activated carbon powder into the plating solution and performing water bath stirring, then performing centrifugal separation, washing with deionized water and placing into an oven for vacuum drying treatment to obtain a nickel-coated carbon material; S5: placing the gallium, indium and tin liquid alloy, the nickel-coated carbon and the silicon carbide into a zirconia ball mill jar according to the proportion and performing ball milling to obtain a liquid metal composite material; S6: performing defoaming treatment on the liquid metal composite material obtained in S5 in a vacuum environment to obtain the final high-thermal-conductivity liquid metal thermal interface composite material.

[0011] Further, as preferably, the temperature is raised to 80-100℃ at a temperature rising rate of 3-6℃ / min in the step S1, and the keeping time is 60-90min.

[0012] Further, as preferably, the temperature is raised to 240-260℃ at a temperature rising rate of 8-12℃ / min in the step S2, and the keeping time is 40-60min.

[0013] Further, as preferably, the weight ratio of NiSO4·6H2O, NaH2PO2·H2O and sodium citrate is 5:5:3 in the step S3.

[0014] Further, as preferably, the ultrasonic treatment is performed at 50-70℃ in the step S3, and the ultrasonic time is 20-40min.

[0015] Further, as preferred, the speed of centrifugal separation in step S4 is 2500-3500 rpm, the time is 3-10 min; the vacuum drying temperature is 80-90 DEG C, the drying time is 1-3 h; the water bath stirring temperature is 80-90 DEG C, and the stirring time is 30-40 min.

[0016] Further, as preferred, the ball milling time in step S5 is 30-60 min, and the ball milling speed is 250-300 rpm.

[0017] Compared with the prior art, the present application has the following beneficial effects: The present application can obtain high-thermal-conductivity liquid metal thermal interface composite material by adding nickel-coated carbon and silicon carbide into liquid gallium-indium-tin metal; the addition of nickel-coated carbon can significantly improve the thermal conductivity of the liquid gallium-indium-tin metal, because on the one hand, the nickel layer can connect the carbon material and the liquid metal as a "thermal bridge", which can reduce the interfacial thermal resistance, and the wettability of nickel and gallium-indium-tin is good, which is easier to form an effective thermal path than directly adding carbon material, on the other hand, the addition of nickel-coated carbon can improve the viscosity of gallium-indium-tin to some extent, thereby inhibiting the random flow of liquid metal; the silicon carbide does not react with gallium-indium-tin at room temperature, and the nanoscale can increase the internal friction resistance of the liquid metal, and can be embedded into the interface between the liquid metal and the substrate, thereby improving the affinity of the material. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 The figure is the thermal conductivity coefficient diagram of the high-thermal-conductivity liquid metal thermal interface composite material prepared in Example 1-Example 3 and Comparative Example 1-Comparative Example 3 of the present application. Figure 2 The figure is the picture of the material prepared in Example 1, Comparative Example 1-3 of the present application smeared on the surface of an aluminum substrate. DETAILED DESCRIPTION

[0019] The specific embodiments of the present application are described in detail below, but it should be understood that the scope of protection of the present application is not limited by the specific embodiments.

[0020] The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

[0021] Example 1: A method for preparing high-thermal-conductivity liquid metal thermal interface composite material, comprising the following steps: S1: solid gallium (purity 99.99%), solid indium (purity 99.995%), solid tin (purity 99.9%), NiSO4·6H2O, NaH2PO2·H2O, sodium citrate, carbon powder, silicon carbide (particle size 200 nm) were prepared as raw materials, and the solid gallium was placed in an oven and kept at 80-100℃ for 60-90min, with a heating rate of 5℃ / min, and the whole experiment was carried out in an argon atmosphere; S2: The molten liquid gallium was taken out, and liquid gallium, solid indium and solid tin were weighed according to the mass ratio of 68.5:21.5:10 and placed in a quartz crucible, and the crucible was placed in an oven and kept at 240-260℃ for 40-60min, with a heating rate of 10℃ / min, and a polytetrafluoroethylene stirring rod was used to stir every 8min, and the natural cooling to room temperature obtained a gallium-indium-tin liquid alloy; S3: The carbon powder was activated by ultrasonic treatment in 5% HNO3 solution at 60℃ for 30min, and the NiSO4·6H2O, NaH2PO2·H2O and sodium citrate were mixed in a ratio of 5:5:3 to prepare a plating solution, and then the pH of the plating solution was adjusted to 9 with 25% ammonia solution; S4: The activated carbon powder was added to the plating solution and stirred in a water bath, the water bath temperature was 80-90℃, the water bath time was 30-40min, then centrifugal separation was carried out, the centrifugal speed was 3000rmp, the time was 5min, and then it was placed in a 80℃ oven for vacuum drying treatment for 2h, and a nickel-coated carbon material with a carbon content of 40-50% was obtained, wherein the particle size of the nickel-coated carbon material was 40μm; S5: The gallium-indium-tin liquid alloy, nickel-coated carbon and silicon carbide were weighed according to the ratio of 98.5:1:0.5 and placed in a zirconia ball mill jar for ball milling, wherein the ratio of balls to materials was 5:1. The ball milling time was 30-60min, and the ball milling speed was 250-300rpm, and a liquid metal composite material was obtained; S6: The liquid metal composite material obtained in S5 was kept in a vacuum environment for 10-20min for defoaming treatment, and a final high thermal conductivity liquid metal thermal interface composite material was obtained.

[0022] The thermal conductivity of the obtained liquid metal thermal interface composite material was measured, and the thermal conductivity was 80.8 W / (m·K).

[0023] Example 2: A method for preparing a high thermal conductivity liquid metal thermal interface composite material, comprising the following steps: S1: Prepare solid gallium (purity 99.99%), solid indium (purity 99.995%), solid tin (purity 99.9%), NiSO4·6H2O, NaH2PO2·H2O, sodium citrate, carbon powder, and silicon carbide (particle size 200nm) as raw materials. Place the solid gallium in an oven and keep it at 80-100℃ for 60-90min, with a heating rate of 5℃ / min. The entire experiment is carried out under an argon atmosphere. S2: Take out the molten liquid gallium, weigh the liquid gallium, solid indium and solid tin in a mass ratio of 68.5:21.5:10, and put them into a quartz crucible. Place the crucible in an oven and keep it at 240-260℃ for 40-60 minutes, with a heating rate of 10℃ / min. Stir with a polytetrafluoroethylene stirring rod every 8 minutes. Let it cool naturally to room temperature to obtain a gallium indium tin liquid alloy. S3: Place the carbon powder in a 5% HNO3 solution and sonicate at 60°C for 30 minutes to activate it. Mix NiSO4·6H2O, NaH2PO2·H2O and sodium citrate in a ratio of 5:5:3 to prepare a plating solution. Then adjust the pH of the plating solution to 9 with 25% ammonia water. S4: Add the activated carbon powder to the plating solution and stir in a water bath at a temperature of 80-90℃ for 30-40 minutes. Then, centrifuge at 3000 rpm for 5 minutes. After washing with deionized water, place the material in an 80℃ oven for vacuum drying for 2 hours to obtain a nickel-coated carbon material with a carbon content of 40-50% and a particle size of 40μm. S5: After weighing the gallium indium tin liquid alloy, nickel-coated carbon, and silicon carbide in a ratio of 97.5:2:0.5, put them into a zirconia ball mill jar for ball milling, where the ratio of balls to materials is 5:1. The ball milling time is 30-60 minutes and the ball milling speed is 250-300 rpm to obtain a liquid metal composite material. S6: The liquid metal composite material obtained in S5 is kept in a vacuum environment for 10-20 minutes to perform degassing treatment, and the final high thermal conductivity liquid metal thermal interface composite material is obtained.

[0024] The thermal conductivity of the liquid metal thermal interface composite material was measured to be 77.7 W / (m·K).

[0025] Example 3: A method for preparing a high thermal conductivity liquid metal thermal interface composite material includes the following steps: S1: solid gallium (purity 99.99%), solid indium (purity 99.995%), solid tin (purity 99.9%), NiSO4·6H2O, NaH2PO2·H2O, sodium citrate, carbon powder, silicon carbide (particle size 200 nm) were prepared as raw materials, and the solid gallium was placed in an oven and kept at 80-100℃ for 60-90min, with a heating rate of 5℃ / min, and the whole experiment was carried out in an argon atmosphere; S2: The molten liquid gallium was taken out, and liquid gallium, solid indium and solid tin were weighed according to the mass ratio of 68.5:21.5:10 and placed in a quartz crucible, and the crucible was placed in an oven and kept at 240-260℃ for 40-60min, with a heating rate of 10℃ / min, and a polytetrafluoroethylene stirring rod was used to stir every 8min, and the gallium-indium-tin liquid alloy was obtained by natural cooling to room temperature; S3: The carbon powder was activated by ultrasonic treatment in 5% HNO3 solution at 60℃ for 30min, and the NiSO4·6H2O, NaH2PO2·H2O and sodium citrate were mixed in a ratio of 5:5:3 to prepare a plating solution, and then the pH of the plating solution was adjusted to 9 by using 25% ammonia water; S4: The activated carbon powder was added to the plating solution and stirred in a water bath, the water bath temperature was 80-90℃, the water bath time was 30-40min, then centrifugal separation was carried out, the centrifugal speed was 3000rmp, the time was 5min, and then it was placed in a 80℃ oven for vacuum drying treatment for 2h, and a nickel-coated carbon material with a carbon content of 40-50% was obtained, wherein the particle size of the nickel-coated carbon material was 40μm; S5: The gallium-indium-tin liquid alloy, nickel-coated carbon and silicon carbide were weighed according to the ratio of 96.5:3:0.5 and placed in a zirconia ball mill jar for ball milling, wherein the ratio of balls to materials was 5:1. The ball milling time was 30-60min, and the ball milling speed was 250-300rpm, and the liquid metal composite material was obtained; S6: The liquid metal composite material obtained in S5 was subjected to debubbling treatment in a vacuum environment for 10-20min to obtain the final high thermal conductivity liquid metal thermal interface composite material.

[0026] The thermal conductivity of the obtained liquid metal thermal interface composite material was measured, and the thermal conductivity was 76.7 W / (m·K).

[0027] Comparative Example 1: A method for preparing a high thermal conductivity liquid metal thermal interface composite material, comprising the following steps: S1: prepare solid gallium (purity 99.99%), solid indium (purity 99.995%), solid tin (purity 99.9%), silicon carbide (particle size 200 nm) as raw materials, put the solid gallium into the oven, heat at 80-100℃ for 60-90min, the heating rate is 5℃ / min, the whole experiment is carried out in argon atmosphere; S2: take out the melted liquid gallium, take liquid gallium, solid indium and solid tin according to the mass ratio of 68.5:21.5:10, and put them into a quartz crucible, put the crucible into the oven, heat at 240-260℃ for 40-60min, the heating rate is 10℃ / min, stir once every 8min using a polytetrafluoroethylene stirring rod, and naturally cool to room temperature to obtain a gallium-indium-tin liquid alloy; S3: put the gallium-indium-tin liquid alloy and silicon carbide into a zirconia ball mill jar according to the ratio of 99.5:0.5, and ball mill, the ratio of ball to material is 5:1, the ball milling time is 30-60min, the ball milling speed is 250-300rpm, and the liquid metal composite material is obtained; S4: keep the liquid metal composite material obtained in S3 in a vacuum environment for 10-20min for defoaming treatment to obtain the final high thermal conductivity liquid metal thermal interface composite material.

[0028] The thermal conductivity of the obtained liquid metal thermal interface composite material is measured, and the thermal conductivity is 79.4W / (m·K).

[0029] Comparative example 2: A method for preparing a high thermal conductivity liquid metal thermal interface composite material, comprising the following steps: S1: prepare solid gallium (purity 99.99%), solid indium (purity 99.995%), solid tin (purity 99.9%), NiSO4·6H2O, NaH2PO2·H2O, sodium citrate, and carbon powder as raw materials, put the solid gallium into the oven, heat at 80-100℃ for 60-90min, the heating rate is 5℃ / min, the whole experiment is carried out in argon atmosphere; S2: take out the melted liquid gallium, take liquid gallium, solid indium and solid tin according to the mass ratio of 68.5:21.5:10, and put them into a quartz crucible, put the crucible into the oven, heat at 240-260℃ for 40-60min, the heating rate is 10℃ / min, stir once every 8min using a polytetrafluoroethylene stirring rod, and naturally cool to room temperature to obtain a gallium-indium-tin liquid alloy; S3: Put the carbon powder into a 5% concentration HNO3 solution and ultrasonic for 30 min at 60℃ for activation treatment. Mix NiSO4·6H2O, NaH2PO2·H2O and sodium citrate according to the ratio of 5:5:3 to prepare the plating solution. Then adjust the pH of the plating solution to 9 by using 25% ammonia water; S4: Add the activated carbon powder into the plating solution and stir in a water bath. The water bath temperature is 80-90℃ and the water bath time is 30-40 min. Then centrifugal separation is performed at a speed of 3000 rmp for 5 min. After washing with deionized water, the material is placed in an 80℃ oven for vacuum drying treatment for 2 h to obtain a nickel-coated carbon material with a carbon content of 40-50%. The particle size of the nickel-coated carbon material is 40 μm. S5: Put the gallium-indium-tin liquid alloy and nickel-coated carbon into a zirconia ball mill jar according to the ratio of 99:1 for ball milling. The ratio of balls to material is 5:1. The ball milling time is 30-60 min and the ball milling speed is 250-300 rpm to obtain a liquid metal composite material. S6: The liquid metal composite material obtained in S5 is subjected to degassing treatment in a vacuum environment for 10-20 min to obtain the final high thermal conductivity liquid metal thermal interface composite material.

[0030] The thermal conductivity of the obtained liquid metal thermal interface composite material is measured, and the thermal conductivity coefficient is 80.7 W / (m·K).

[0031] Comparative Example 3: A method for preparing a high thermal conductivity liquid metal thermal interface composite material, comprising the following steps: S1: Prepare solid gallium (purity 99.99%), solid indium (purity 99.995%) and solid tin (purity 99.9%) as raw materials. Put the solid gallium into an oven and heat at 80-100℃ for 60-90 min. The heating rate is 5℃ / min. The experiment is carried out in an argon atmosphere. S2: Take out the melted liquid gallium, and weigh the liquid gallium, solid indium and solid tin according to the mass ratio of 68.5:21.5:10, and put them into a quartz crucible. Put the crucible into an oven and heat at 240-260℃ for 40-60 min. The heating rate is 10℃ / min. Stir every 8 min with a polytetrafluoroethylene stirring rod. Naturally cool to room temperature to obtain a gallium-indium-tin liquid alloy. S3: The gallium-indium-tin liquid alloy material obtained in S2 is subjected to degassing treatment in a vacuum environment for 10-20 min to obtain the final high thermal conductivity liquid metal thermal interface composite material.

[0032] The thermal conductivity of the obtained liquid metal thermal interface composite material is measured, and the thermal conductivity coefficient is 79.2 W / (m·K).

[0033] Performance testing and results analysis: Appendix Figure 1 The figure shows the thermal conductivity of the high thermal conductivity liquid metal thermal interface composite materials prepared in Examples 1-3 and Comparative Examples 1-3. It can be seen from the figure that adding appropriate amounts of nickel-coated carbon and silicon carbide can significantly improve the thermal conductivity of the liquid metal thermal interface composite material. Appendix Figure 2 The images shown are of the materials prepared in Example 1 and Comparative Examples 1-3 coated on the surface of an aluminum substrate. As can be seen from the images, the liquid metal thermal interface composite material with appropriate amounts of nickel-coated carbon and silicon carbide has better affinity, can be evenly coated on the surface of the aluminum substrate, and does not flow easily.

[0034] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A high thermal conductive liquid metal thermal interface composite, characterized in that, The raw materials include the following components by weight: 60-90 parts of gallium, 10-25 parts of indium, 0-20 parts of tin, 1-3 parts of carbon-coated nickel, and 0.01-1 parts of silicon carbide.

2. The high thermal conductive liquid metal thermal interface composite of claim 1, wherein, The content of nickel in the carbon-coated nickel is 40-50%.

3. The high thermal conductive liquid metal thermal interface composite of claim 1, wherein, The particle size of the silicon carbide is 30 nm-1 μm.

4. A method of making the high thermal conductive liquid metal thermal interface composite of any one of claims 1-3, characterized in that, The method comprises the following steps: S1: preparing solid gallium, solid indium, solid tin, NiSO4·6H2O, NaH2PO2·H2O, sodium citrate, carbon powder, and silicon carbide as raw materials, and placing the solid gallium into an oven and keeping it at 80-100°C; S2: taking out the molten liquid gallium, weighing the liquid gallium, solid indium, and solid tin according to the mass ratio, and placing them into a quartz crucible, and placing the crucible into an oven and keeping it at 240-260°C, and mixing the gallium-indium-tin material uniformly with a stirring paddle during the keeping process, and naturally cooling it to room temperature to obtain a gallium-indium-tin liquid alloy; S3: placing the carbon powder into a 5% concentration HNO3 solution and performing ultrasonic activation treatment, mixing NiSO4·6H2O, NaH2PO2·H2O, and sodium citrate to prepare a plating solution, and adjusting the PH of the plating solution to alkaline with ammonia water; S4: adding the activated carbon powder into the plating solution and water-bath stirring, and then performing centrifugal separation, and washing with deionized water and then placing it into an oven for vacuum drying treatment to obtain a carbon-coated nickel material; S5: placing the gallium-indium-tin liquid alloy, carbon-coated nickel, and silicon carbide into a zirconia ball mill jar according to the proportion and performing ball milling to obtain a liquid metal composite material; S6: performing defoaming treatment on the liquid metal composite material obtained in S5 in a vacuum environment to obtain a final high-thermal-conductivity liquid metal thermal interface composite material.

5. The method of claim 4, wherein the high thermally conductive liquid metal thermal interface composite is prepared by the steps of: In the step S1, the temperature is raised to 80-100°C at a rate of 3-6°C / min, and the keeping time is 60-90 min.

6. The method of claim 4, wherein the high thermally conductive liquid metal thermal interface composite is prepared by the steps of: In the step S2, the temperature is raised to 240-260°C at a rate of 8-12°C / min, and the keeping time is 40-60 min.

7. The method for preparing a high thermal conductivity liquid metal thermal interface composite material according to claim 4, characterized in that, In the step S3, the weight ratio of NiSO4·6H2O, NaH2PO2·H2O, and sodium citrate is 5:5:

3.

8. The method for preparing a high thermal conductivity liquid metal thermal interface composite material according to claim 4, characterized in that, In the step S3, the ultrasonic treatment is performed at 50-70°C, and the ultrasonic time is 20-40 min.

9. The method for preparing a high thermal conductivity liquid metal thermal interface composite material according to claim 4, characterized in that, In the step S4, the centrifugal separation speed is 2500-3500 rmp, and the time is 3-10 min; the vacuum drying temperature is 80-90°C, and the drying time is 1-3 h; and the water-bath stirring temperature is 80-90°C, and the stirring time is 30-40 min.

10. The method for preparing a high thermal conductivity liquid metal thermal interface composite material according to claim 4, characterized in that, In the step S5, the ball milling time is 30-60 min, and the ball milling speed is 250-300 rpm.

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