Heat-conducting gasket and preparation method thereof
By setting a catalyst on the surface of the thermal film of the graphene thermal gasket and growing carbon nanotubes to form a sandwich composite structure, the existing thermal gaskets have been solved, and efficient thermal conductivity and high temperature stability have been achieved.
Patent Information
- Application Number
- CN202510190091.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-20
- Publication Date
- 2025-05-27
AI Technical Summary
The existing graphene thermal conductivity has poor lateral thermal conductivity, and its temperature resistance is generally below 300℃, making it difficult to meet the use of high temperature scenarios.
By providing a catalyst on the surface of the first and second thermal conductive films, carbon nanotubes are grown by chemical vapor deposition method to form a sandwich composite structure of graphene film-carbon nanotube-graphene film, thereby enhancing thermal conductivity and high temperature stability.
It achieves better transverse and longitudinal thermal conductivity of thermal gaskets, has excellent high temperature stability, high strength and good compression, and expands the application scenario.
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Figure CN120041804A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of heat conduction technology. Specifically, it relates to a heat conduction gasket and a preparation method thereof. Background Art
[0002] With the continuous progress of technology, the integration and power consumption of electronic devices have also been increasing continuously, which results in a large amount of heat generated during the operation of electronic devices. If this heat cannot be dissipated in a timely and effective manner, it will lead to a decline in the performance of electronic devices and may even cause safety accidents. Therefore, how to effectively dissipate heat has become a key issue in the design and manufacture of electronic devices.
[0003] In the field of nanotechnology, graphene has become a hot material for solving this problem due to its excellent heat conduction performance. Graphene is a two-dimensional carbon material with an extremely high thermal conductivity, which can reach more than 5300 W / (m·K).
[0004] The existing graphene heat conduction gaskets mainly adopt the method of stacking multiple graphene films, and adhesives are added between the graphene films to improve their mechanical strength and heat conduction performance. However, the heat conduction performance of this structure is limited by the number of graphene film layers and the performance of the adhesive, and its lateral heat conduction performance is poor, and the temperature resistance performance is generally below 300°C, making it difficult to meet the use in high-temperature scenarios. Summary of the Invention
[0005] This application provides a heat conduction gasket and a preparation method thereof, which have both good lateral heat conduction performance and longitudinal heat conduction performance, and have excellent high-temperature stability.
[0006] The embodiments of this application are implemented as follows:
[0007] In a first aspect, an embodiment of this application provides a preparation method of a heat conduction gasket, which includes: preparing a first heat conduction film and a second heat conduction film. The first heat conduction film has a first surface, and a plurality of mutually separated first regions are arranged on the first surface. The second heat conduction film has a second surface, and a plurality of mutually separated second regions are arranged on the second surface. Catalysts for growing carbon nanotubes are arranged in both the plurality of first regions and the plurality of second regions. The first heat conduction film and the second heat conduction film are arranged relatively, with the first surface facing the second surface, and the positive projection of the first region on the first surface on the second surface has no overlapping region with the second region and is staggered. Chemical vapor deposition is used to grow a plurality of carbon nanotubes between the first heat conduction film and the second heat conduction film.
[0008] In the above technical solution, the preparation method of the thermal conductive gasket of the present application is to first set catalysts for growing carbon nanotubes in a plurality of mutually separated first regions on the first surface of the first thermal conductive film and a plurality of mutually separated second regions on the second surface of the second thermal conductive film, and then use chemical vapor deposition to grow a plurality of carbon nanotubes between the first thermal conductive film and the second thermal conductive film. The plurality of carbon nanotubes are precisely arranged and distributed according to the set positions of the catalysts, and a part of the plurality of carbon nanotubes grows out from the first surface of the first thermal conductive film, and the other part grows out from the second surface of the second thermal conductive film. The carbon nanotubes growing out from the first surface of the first thermal conductive film and the carbon nanotubes growing out from the second surface of the second thermal conductive film are staggered and distributed, and are connected with each other, so that the first thermal conductive film and the second thermal conductive film no longer need to be bonded with an adhesive. The preparation method of the thermal conductive gasket of the present application is simple, which is beneficial to reducing the production cost and improving the production efficiency. The prepared thermal conductive gasket has a sandwich composite structure of graphene film - carbon nanotube - graphene film, and has both good lateral thermal conductivity and longitudinal thermal conductivity, and has excellent high-temperature stability, high strength and good compressibility, thereby expanding the application scenarios of the thermal conductive gasket.
[0009] In some possible implementation manners, the orthographic projections of the plurality of first regions on the first surface on the second surface are arranged in an array with the plurality of second regions.
[0010] In the above technical solution, since the growth of carbon nanotubes by chemical vapor deposition uses the regions provided with catalysts as the growth points, by making the orthographic projections of the plurality of first regions on the first surface on the second surface be arranged in an array with the plurality of second regions, it can be ensured that the plurality of carbon nanotubes growing out from the first surface of the first thermal conductive film and the plurality of carbon nanotubes growing out from the second surface of the second thermal conductive film are arranged in an array as a whole.
[0011] In some possible implementation manners, the chemical vapor deposition method includes first introducing a reducing gas, then introducing a mixed gas including a carbon source gas and an inert gas, and keeping the temperature at 600°C to 800°C for 30 min to 300 min.
[0012] In some possible implementation manners, before setting the catalysts in the first region and the second region, the roughness of the first surface and the second surface is increased by surface treatment first.
[0013] In the above technical solution, before setting the catalysts in the first region and the second region, the roughness of the first surface and the second surface is increased by surface treatment first, which is beneficial to improving the adhesion and uniform distribution of the catalysts on the first surface and the second surface, and thus it is easy to precisely control the growth and arrangement distribution of the carbon nanotubes.
[0014] In some possible embodiments, the method of disposing a catalyst in the first region and / or in a plurality of second regions includes: covering the first surface and / or the second surface with a mask, then disposing the catalyst on the first surface and / or the second surface, and finally removing the mask on the first surface and / or the second surface.
[0015] In the above technical solution, after covering the first surface and / or the second surface with a mask, it is beneficial to divide a plurality of separated first regions and / or second regions. Then, when disposing the catalyst on the first surface and / or the second surface, the catalyst can be disposed in the first region and / or the second region. Finally, after removing the mask on the first surface and / or the second surface, the growth of carbon nanotubes can be carried out.
[0016] In some possible embodiments, the catalyst includes a solution containing iron ions;
[0017] Optionally, the catalyst includes a ferric nitrate solution;
[0018] Optionally, the concentration of iron ions in the catalyst is 1 mol / L to 2 mol / L.
[0019] In some possible embodiments, the thickness of the first heat-conducting film and / or the second heat-conducting film is 10 μm to 1000 μm;
[0020] Optionally, the thickness of the first heat-conducting film and / or the second heat-conducting film is 30 μm to 100 μm.
[0021] In the above technical solution, by making the thickness of the first heat-conducting film and / or the second heat-conducting film within the above range, it is beneficial to improve the strength and compression performance of the obtained heat-conducting gasket.
[0022] In some possible embodiments, the distance between the first heat-conducting film and the second heat-conducting film is 50 μm to 1000 μm;
[0023] Optionally, the distance between the first heat-conducting film and the second heat-conducting film is 50 μm to 500 μm.
[0024] In the above technical solution, by making the distance between the first heat-conducting film and the second heat-conducting film within the above range, it is beneficial to precisely control the height of the carbon nanotubes grown by chemical vapor deposition.
[0025] In some possible embodiments, the first heat-conducting film and / or the second heat-conducting film includes a graphene film or a boron nitride film.
[0026] In the above technical solution, the graphene film has good heat conductivity, and the boron nitride film has good insulation.
[0027] In a second aspect, an example of the present application provides a thermal conductive gasket, which is prepared according to the preparation method of the thermal conductive gasket in the above embodiment.
[0028] In the above technical solution, the thermal conductive gasket of the present application has both good lateral thermal conductivity and longitudinal thermal conductivity, and has excellent high-temperature stability, high strength and good compressibility, thereby expanding the application scenarios of the thermal conductive gasket. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required for the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.
[0030] Figure 1 It is a schematic structural diagram of the thermal conductive gasket of the embodiment of the present application;
[0031] Figure 2 It is a distribution diagram of the first carbon nanotubes on the first thermal conductive film of the first embodiment of the present application;
[0032] Figure 3 It is a distribution diagram of the second carbon nanotubes on the second thermal conductive film of the first embodiment of the present application;
[0033] Figure 4 It is a distribution diagram of the first carbon nanotubes on the first thermal conductive film of the second embodiment of the present application;
[0034] Figure 5 It is a distribution diagram of the second carbon nanotubes on the second thermal conductive film of the second embodiment of the present application.
[0035] ICON: 10 - Thermal conductive gasket; 100 - First thermal conductive film; 200 - Second thermal conductive film; 300 - Carbon nanotube group; 301 - Gap; 310 - First carbon nanotube; 320 - Second carbon nanotube. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0036] The following will describe the implementation solutions of the present application in detail in conjunction with the embodiments. However, those skilled in the art will understand that the following embodiments are only used to illustrate the present application and should not be regarded as limiting the scope of the present application. For those not specified in the embodiments, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer. Those reagents or instruments not specified by the manufacturer can be obtained as conventional products through commercial purchase.
[0037] Graphene thermal pads have the defects of poor lateral thermal conductivity and difficulty in meeting the requirements of high-temperature scenarios. At the same time, due to the structure of graphene thermal pads, they usually also have problems of insufficient strength and compressibility, which limits their use in large-scale industrial applications.
[0038] Carbon nanotubes (CNTs) are nanomaterials composed of carbon atoms, with excellent mechanical, electrical, and thermal properties. Carbon nanotubes can be divided into single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs). Among them, single-walled carbon nanotubes are more common in practical applications due to their good structural stability, high thermal conductivity, ease of preparation, and functionalization.
[0039] This application envisions that combining a graphene film and carbon nanotubes can improve the problems of poor lateral thermal conductivity, insufficient strength, and compressibility existing in existing graphene thermal pads. However, how to precisely design the structures of the graphene film and carbon nanotubes and control the arrangement and distribution of carbon nanotubes becomes the key.
[0040] Based on this, this application provides a method for preparing a thermal pad, which includes the following steps:
[0041] S1. Preparation
[0042] First, prepare a first thermal film and a second thermal film. The first thermal film has a first surface, and the second thermal film has a second surface. Set a plurality of mutually separated first regions on the first surface, and set a plurality of mutually separated second regions on the second surface. Then, respectively set catalysts for growing carbon nanotubes in the plurality of first regions and the plurality of second regions. Next, fix the first thermal film and the second thermal film to a special fixture at a certain distance from each other, so that the first thermal film and the second thermal film are arranged opposite to each other. At this time, the first surface faces the second surface, and the orthographic projection of the first region of the first surface on the second surface has no overlapping region with the second region and is staggered. Then, place the special fixture loaded with the first thermal film and the second thermal film in a container for chemical vapor deposition.
[0043] Among them, the first thermal film and / or the second thermal film includes a graphene film or a boron nitride film. The graphene film has good thermal conductivity, and the boron nitride film has good insulation.
[0044] Optionally, both the first thermal film and the second thermal film are graphene films.
[0045] The thickness of the first thermal film and / or the second thermal film is 10 μm to 1000 μm.
[0046] As an example, the thickness of the first heat-conducting film and / or the second heat-conducting film can be 10μm, 20μm, 50μm, 100μm, 200μm, 300μm, 400μm, 500μm, 600μm, 600μm, 700μm, 800μm, 900μm or 1000μm.
[0047] Optionally, the thickness of the first heat-conducting film and / or the second heat-conducting film is 30μm to 100μm.
[0048] By making the thickness of the first heat-conducting film and / or the second heat-conducting film within the above range, it is beneficial to improve the strength and compression performance of the prepared heat-conducting gasket.
[0049] Optionally, before setting the catalyst in the first region and the second region, the roughness of the first surface and the second surface is increased by surface treatment first, which is beneficial to improving the adhesion and uniform distribution of the catalyst on the first surface and the second surface, and then it is easy to precisely control the growth and arrangement distribution of the carbon nanotubes.
[0050] Optionally, the method of setting the catalyst in the first region and / or in multiple second regions includes: covering the first surface and / or the second surface with a mask, which is beneficial to dividing multiple separated first regions and / or second regions, then setting the catalyst on the first surface and / or the second surface, so that the catalyst can be set in the first region and / or the second region, and finally, after removing the mask on the first surface and / or the second surface, the growth of carbon nanotubes can be carried out.
[0051] The catalyst includes a solution containing iron ions;
[0052] Optionally, the catalyst includes ferric nitrate solution;
[0053] Optionally, the concentration of iron ions in the catalyst is 1mol / L to 2mol / L.
[0054] After fixing the first heat-conducting film and the second heat-conducting film on a special fixture, the distance between the first heat-conducting film and the second heat-conducting film is 50μm to 1000μm.
[0055] As an example, the distance between the first heat-conducting film and the second heat-conducting film can be 50μm, 80μm, 100μm, 200μm, 300μm, 400μm, 500μm, 600μm, 600μm, 700μm, 800μm, 900μm or 1000μm.
[0056] Optionally, the distance between the first heat-conducting film and the second heat-conducting film is 50μm to 500μm.
[0057] By making the distance between the first heat-conducting film and the second heat-conducting film within the above range, it is beneficial to precisely control the height of the carbon nanotubes grown by chemical vapor deposition.
[0058] Optionally, the orthographic projections of the multiple first regions on the first surface on the second surface and the multiple second regions are arranged in an array.
[0059] Since the growth of carbon nanotubes by chemical vapor deposition takes the region provided with the catalyst as the growth point, by making the orthographic projections of the multiple first regions on the first surface on the second surface and the multiple second regions be arranged in an array, it can be made that the multiple carbon nanotubes grown from the first surface of the first heat-conducting film and the carbon nanotubes grown from the second surface of the second heat-conducting film are arranged in an array as a whole.
[0060] S2. Grow carbon nanotubes
[0061] Grow multiple carbon nanotubes between the first heat-conducting film and the second heat-conducting film by chemical vapor deposition.
[0062] The chemical vapor deposition method includes first introducing a reducing gas to reduce the iron ions in the catalyst to form iron nanoparticles, and then introducing a mixed gas including a carbon source gas and an inert gas, and keeping it at 600 °C to 800 °C for 30 min to 300 min.
[0063] Among them, the reducing gas includes hydrogen, and the reduction time is 0.5 h to 2 h; the carbon source gas includes C 2 H 2 .
[0064] The preparation method of the heat-conducting gasket of the present application first sets catalysts for growing carbon nanotubes in multiple mutually separated first regions on the first surface of the first heat-conducting film and multiple mutually separated second regions on the second surface of the second heat-conducting film, and then grows multiple carbon nanotubes between the first heat-conducting film and the second heat-conducting film by chemical vapor deposition. The multiple carbon nanotubes are precisely arranged and distributed according to the set catalyst positions, and a part of the multiple carbon nanotubes grows from the first surface of the first heat-conducting film, and the other part grows from the second surface of the second heat-conducting film. The multiple carbon nanotubes grown from the first surface of the first heat-conducting film and the carbon nanotubes grown from the second surface of the second heat-conducting film are staggered and distributed, and are connected with each other, so that the first heat-conducting film and the second heat-conducting film no longer need to be bonded with an adhesive. The preparation method of the heat-conducting gasket of the present application is simple, which is beneficial to reducing the production cost and improving the production efficiency. The prepared heat-conducting gasket has a sandwich composite structure of graphene film - carbon nanotube - graphene film, and has both good lateral heat-conducting performance and longitudinal heat-conducting performance, and has excellent high-temperature stability, high strength and good compressibility, thereby expanding the application scenarios of the heat-conducting gasket.
[0065] It should be noted that the longitudinal thermal conductivity refers to the thermal conductivity of the thermal pad along its thickness direction, and the transverse thermal conductivity refers to the thermal conductivity of the thermal pad along the direction perpendicular to its thickness direction.
[0066] The present application also provides a thermal pad, which is prepared according to the preparation method of the thermal pad in the above embodiment.
[0067] Please refer to Figure 1 , the thermal pad 10 includes a first thermal conductive film 100, a second thermal conductive film 200 and a carbon nanotube group 300. The first thermal conductive film 100 and the second thermal conductive film 200 are spaced apart, and the carbon nanotube group 300 is disposed between the first thermal conductive film 100 and the second thermal conductive film 200.
[0068] Among them, the first thermal conductive film 100 and / or the second thermal conductive film 200 is a graphene film or a boron nitride film. The graphene film has good thermal conductivity, and the boron nitride film has good insulation.
[0069] Optionally, both the first thermal conductive film 100 and the second thermal conductive film 200 are graphene films.
[0070] Optionally, the first thermal conductive film 100 and the second thermal conductive film 200 are parallel to each other, which is beneficial to improving the uniformity of the entire thermal pad 10.
[0071] The carbon nanotube group 300 includes a plurality of first carbon nanotubes 310 and at least one second carbon nanotube 320. One end of the plurality of first carbon nanotubes 310 is connected to the first thermal conductive film 100, and the other end abuts against the second thermal conductive film 200. One end of the at least one second carbon nanotube 320 is connected to the second thermal conductive film 200, and the other end abuts against the first thermal conductive film 100, and there is a gap 301 between the plurality of first carbon nanotubes 310. The at least one second carbon nanotube 320 is inserted into the gap 301 to connect the first thermal conductive film 100 and the second thermal conductive film 200.
[0072] Please refer to Figures 2 - 3 , a plurality of first carbon nanotubes 310 are connected to the first thermal conductive film 100, and a gap 301 is formed between the plurality of first carbon nanotubes 310. One second carbon nanotube 320 is connected to the second thermal conductive film 200, and one second carbon nanotube 320 is used to be inserted into the gap 301 formed between the plurality of first carbon nanotubes 310 to connect the first thermal conductive film 100 and the second thermal conductive film 200.
[0073] Please refer to Figures 4 - 5, a plurality of first carbon nanotubes 310 are connected to the first heat-conducting film 100, and a plurality of gaps 301 are formed between the plurality of first carbon nanotubes 310. A plurality of second carbon nanotubes 320 are connected to the second heat-conducting film 200, and the plurality of second carbon nanotubes 320 are used to be inserted into the plurality of gaps 301 formed between the plurality of first carbon nanotubes 310 one by one, so that the first heat-conducting film 100 and the second heat-conducting film 200 are connected.
[0074] Optionally, the plurality of first carbon nanotubes 310 and the plurality of second carbon nanotubes 320 are staggered, which is beneficial to improving the bonding property between the plurality of first carbon nanotubes 310 and the plurality of second carbon nanotubes 320, and making the structure of the whole heat-conducting gasket 10 more stable.
[0075] Optionally, the carbon nanotube group 300 is arranged in an array. The carbon nanotube group 300 arranged in an array not only has a stable structure, but also can improve the strength and compression performance of the heat-conducting gasket 10.
[0076] Optionally, the included angle between the axis of the first carbon nanotube 310 and the first heat-conducting film 100 is 45° to 90°, and / or; the included angle between the axis of the second carbon nanotube 320 and the second heat-conducting film 200 is 45° to 90°.
[0077] As an example, the included angle between the axis of the first carbon nanotube 310 and the first heat-conducting film 100 and / or the included angle between the axis of the second carbon nanotube 320 and the second heat-conducting film 200 can be 45°, 50°, 60°, 70°, 80° or 90°.
[0078] By making the included angle between the axis of the first carbon nanotube 310 and the first heat-conducting film 100 and / or the included angle between the axis of the second carbon nanotube 320 and the second heat-conducting film 200 within the above range, it is beneficial to make the heat-conducting gasket 10 take into account both heat-conducting performance and compressibility.
[0079] Optionally, the diameter of the carbon nanotube is 1 nm to 1000 nm.
[0080] As an example, the diameter of the carbon nanotube can be 1 nm, 2 nm, 5 nm, 10 nm, 50 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, or 1000 nm.
[0081] The thermal conductive gasket 10 of the present application forms a sandwich composite structure of graphene film - carbon nanotubes - graphene film by arranging a carbon nanotube group 300 including a plurality of carbon nanotubes between the first thermal conductive film 100 and the second thermal conductive film 200 which are distributed at intervals. Moreover, a plurality of first carbon nanotubes 310 in the carbon nanotube group 300 are connected to the first thermal conductive film 100, and at least one second carbon nanotube 320 is connected to the second thermal conductive film 200. The plurality of first carbon nanotubes 310 connected to the first thermal conductive film 100 and at least one second carbon nanotube 320 connected to the second thermal conductive film 200 are connected to each other in cooperation. As a result, the first thermal conductive film 100 and the second thermal conductive film 200 no longer need to be bonded by an adhesive. The thermal conductive gasket 10 has both good lateral thermal conductivity and longitudinal thermal conductivity, and has excellent high - temperature stability, high strength and good compressibility, thereby expanding the application scenarios of the thermal conductive gasket 10.
[0082] The following further describes in detail a thermal conductive gasket and its preparation method of the present application with reference to embodiments.
[0083] Embodiment 1
[0084] The embodiment of the present application provides a thermal conductive gasket and its preparation method, which includes the following steps:
[0085] S1. Preparation work
[0086] First, prepare a first graphene film and a second graphene film. The thicknesses of both the first graphene film and the second graphene film are 50 μm. The first graphene film has a first surface, and the second graphene film has a second surface. The plasma surface treatment is performed on the first surface and the second surface to increase their roughness. The first surface and the second surface are covered with a mask. A plurality of mutually separated first regions are demarcated on the first surface, and a plurality of mutually separated second regions are demarcated on the second surface. Then, spray a ferric nitrate solution with a concentration of 1 mol / L on the first surface and the second surface respectively, so that the ferric nitrate solution is sprayed in the plurality of first regions and the plurality of second regions, and remove the mask on the first surface and the second surface; then fix the first graphene film and the second graphene film to a special fixture with a distance of 50 μm between them respectively, so that the first graphene film and the second graphene film are arranged oppositely. At this time, the first surface faces the second surface, and the orthographic projection of the first region on the first surface on the second surface has no overlapping region with the second region and is arranged in an array. Then, set the special fixture loaded with the first graphene film and the second graphene film in a tube furnace.
[0087] S2. Growing carbon nanotubes
[0088] Heat the tube furnace to 680 °C, and pass H 2 at a flow rate of 30 mL / min, and keep the temperature constant for 1 h; then pass C 2 H 2The mixed gas of C and Ar starts to react. 2 H 2 The flow rate of H is 20 mL / min, and the flow rate of Ar is 300 mL / min. After reacting for 30 min, a plurality of carbon nanotubes are grown between the first graphene film and the second graphene film. Then, the temperature is lowered to room temperature to obtain the thermal conductive gasket.
[0089] Example 2
[0090] The embodiment of the present application provides a thermal conductive gasket and a preparation method thereof, which include the following steps:
[0091] S1. Preparation work
[0092] First, prepare the first graphene film and the second graphene film. The thicknesses of the first graphene film and the second graphene film are both 50 μm. The first graphene film has a first surface, and the second graphene film has a second surface. The first surface and the second surface are subjected to plasma surface treatment to increase their roughness. A mask is used to cover the first surface and the second surface. A plurality of separate first regions are defined on the first surface, and a plurality of separate second regions are defined on the second surface. Then, a ferric nitrate solution with a concentration of 1 mol / L is sprayed onto the first surface and the second surface respectively, so that the ferric nitrate solution is sprayed into the plurality of first regions and the plurality of second regions. The mask on the first surface and the second surface is removed. Then, the first graphene film and the second graphene film are fixed to a special fixture at an interval of 300 μm respectively, so that the first graphene film and the second graphene film are arranged opposite to each other. At this time, the first surface faces the second surface, and the orthographic projection of the first region on the first surface on the second surface has no overlapping region with the second region and is arranged in an array. Then, the special fixture loaded with the first graphene film and the second graphene film is placed in a tube furnace.
[0093] S2. Growing carbon nanotubes
[0094] The tube furnace is heated to 680 °C, and H is passed through at a flow rate of 30 mL / min. 2 After maintaining the temperature for 1 h, C 2 H 2 The mixed gas of C and Ar starts to react. 2 H 2 The flow rate of H is 20 mL / min, and the flow rate of Ar is 300 mL / min. After reacting for 200 min, a plurality of carbon nanotubes are grown between the first graphene film and the second graphene film. Then, the temperature is lowered to room temperature to obtain the thermal conductive gasket.
[0095] Example 3
[0096] The comparative example of the present application provides a thermal conductive gasket and a preparation method thereof, which include the following steps:
[0097] S1. Preparation work
[0098] First, prepare a first graphene film and a second graphene film. The thicknesses of both the first graphene film and the second graphene film are 100 μm. The first graphene film has a first surface, and the second graphene film has a second surface. Perform plasma surface treatment on the first surface and the second surface to increase their roughness. Cover the first surface with a mask, and divide the first surface into multiple separated first regions. Then, spray a ferric nitrate solution with a concentration of 1 mol / L onto the first surface, such that the ferric nitrate solution is sprayed onto multiple first regions and multiple second regions. Remove the mask from the first surface and the second surface. Then, fix the first graphene film and the second graphene film to a special fixture with a distance of 50 μm between them, such that the first graphene film and the second graphene film are arranged opposite to each other. At this time, the first surface faces the second surface, and the orthographic projection of the first region of the first surface on the second surface has no overlapping region with the second region and is arranged in an array. Then, place the special fixture loaded with the first graphene film and the second graphene film into a tube furnace.
[0099] S2. Grow carbon nanotubes
[0100] Heat the tube furnace to 680 °C, and introduce H 2 , and keep it at a constant temperature for 1 h. Then, introduce a mixed gas of C 2 H 2 and Ar to start the reaction. The flow rate of C 2 H 2 is 20 mL / min, and the flow rate of Ar is 300 mL / min. After reacting for 30 min, a plurality of carbon nanotubes grow between the first graphene film and the second graphene film. Cool down to room temperature to obtain a thermal conductive gasket.
[0101] Comparative Example 1
[0102] The comparative example of this application provides a thermal conductive gasket and its preparation method, which includes the following steps:
[0103] S1. Preparation work
[0104] First, prepare the first graphene film and the second graphene film. The thickness of both the first graphene film and the second graphene film is 100 μm. The first graphene film has a first surface, and the second graphene film has a second surface. The first surface and the second surface are subjected to plasma surface treatment to increase their roughness. A mask is used to cover the first surface and the second surface. Multiple separate first regions are demarcated on the first surface. The multiple first regions on the first surface are arranged in an array. Then, a ferric nitrate solution with a concentration of 1 mol / L is sprayed onto the first surface, such that the ferric nitrate solution is sprayed onto the multiple first regions, and the mask on the first surface is removed. Subsequently, the first graphene film and the second graphene film are fixed to a special fixture with a spacing of 50 μm, such that the first graphene film and the second graphene film are arranged opposite to each other. At this time, the first surface faces the second surface, and the orthographic projection of the first regions on the first surface on the second surface has no overlapping regions with the second regions and is arranged in an array. Then, the special fixture loaded with the first graphene film and the second graphene film is placed in a tube furnace.
[0105] S2. Grow carbon nanotubes
[0106] Heat the tube furnace to 680 °C, and pass H 2 , keep it at a constant temperature for 1 h; then pass in a mixed gas of C 2 H 2 and Ar to start the reaction. The flow rate of C 2 H 2 is 20 mL / min, and the flow rate of Ar is 300 mL / min. After reacting for 30 min, multiple carbon nanotubes are grown between the first graphene film and the second graphene film. Cool down to room temperature to obtain a thermal conductive gasket.
[0107] Comparative Example 2
[0108] The comparative example of this application provides a thermal conductive gasket and its preparation method, which includes, on the basis of Comparative Example 1, using an adhesive to bond the top ends of the carbon nanotubes to the second surface of the second graphene film to form a thermal conductive gasket.
[0109] Test Example 1
[0110] Take the thermal conductive gaskets prepared in Examples 1 - 3 and Comparative Examples 1 - 2, observe their structural stability, and measure their transverse thermal conductivity, longitudinal thermal conductivity, compression ratio, strength, and high-temperature stability. The results are shown in Table 1.
[0111] The test methods are as follows:
[0112] 1. Transverse thermal conductivity and longitudinal thermal conductivity
[0113] Transverse thermal conductivity test: The Netzsch LFA467 device was used to test the thermal diffusivity. The gasket was cut into a size with a diameter of 25.4 mm, and the in-plane test mode was selected to measure the thermal diffusivity. Then, the specific heat capacity of the gasket was measured by DSC differential scanning calorimetry, and the density of the gasket was measured by the drainage method. Finally, the thermal conductivity was calculated using the formula: thermal conductivity = thermal diffusivity * specific heat capacity * density.
[0114] Longitudinal thermal conductivity test: The Netzsch LFA467 device was used to test the thermal diffusivity. The gasket was cut into a size with a diameter of 12.7 mm, and the conventional test mode was selected to measure the thermal diffusivity. Then, the specific heat capacity of the gasket was measured by DSC differential scanning calorimetry, and the density of the gasket was measured by the drainage method. Finally, the thermal conductivity was calculated using the formula: thermal conductivity = thermal diffusivity * specific heat capacity * density.
[0115] 2. Compression ratio
[0116] The INSTRON 6800 universal testing machine was used to conduct the compressibility test. The test pressure was 20 psi, and the compression ratio = (initial thickness - compressed thickness) * 100 / initial thickness.
[0117] 3. Strength
[0118] A mechanical tensile machine was used to cut the material into a standard dumbbell shape for strength testing.
[0119] 4. High-temperature stability
[0120] The thermal conductive gasket was placed in an oven at 300 °C for 1 h, and then its damage condition was observed.
[0121] Table 1 Performance of the thermal conductive gaskets in Examples 1-3 and Comparative Examples 1-2
[0122]
[0123] As can be seen from Examples 1-3, the thermal conductive gasket structure of the embodiments of the present application is stable without separation, and the transverse thermal conductivity is 1900 W / mK - 1950 W / mK, the longitudinal thermal conductivity is 1320 W / mK - 1450 W / mK, the compression ratio is 62.5% - 75.8%, the strength is 0.24 MPa - 0.43 MPa, and the high-temperature stability is good.
[0124] By comparing Comparative Example 1 with Example 1, it can be seen that in Comparative Example 1, only a catalyst was set on the first graphene film and carbon nanotubes were grown by chemical vapor deposition. The carbon nanotubes grown on the first graphene film in the thermal conductive gasket could not be combined with the second graphene film, that is, they were in a separated state.
[0125] From the comparison between Comparative Example 2 and Example 1, it can be seen that all the carbon nanotubes in Comparative Example 2 grew on the first graphene film, and the tops of the carbon nanotubes were bonded to the second graphene film through an adhesive to stably link the first graphene film and the second graphene film. The transverse thermal conductivity of the thermal conductive gasket in Comparative Example 2 was only 1350 W / mK, and the longitudinal thermal conductivity was only 950 W / mK, which was far lower than the transverse and longitudinal thermal conductivities of the thermal conductive gasket in Example 1.
[0126] The above are only specific embodiments of the present application and are not intended to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims
1. A method for preparing a thermally conductive gasket, characterized in that: The preparation method of the thermally conductive gasket includes: preparing a first thermally conductive film and a second thermally conductive film, wherein the first thermally conductive film has a first surface, the first surface is provided with a plurality of first regions separated from each other, the second thermally conductive film has a second surface, the second surface is provided with a plurality of second regions separated from each other, a catalyst for growing carbon nanotubes is provided in each of the plurality of first regions and the plurality of second regions, the first thermally conductive film and the second thermally conductive film are arranged relative to each other, the first surface faces the second surface, and the orthographic projection of the first region of the first surface on the second surface has no overlapping region with the second region and is staggeredly distributed, and a plurality of carbon nanotubes are grown between the first thermally conductive film and the second thermally conductive film by using a chemical vapor deposition method.
2. The method for preparing a thermally conductive gasket according to claim 1, characterized in that: The orthographic projections of the plurality of first regions of the first surface on the second surface and the plurality of second regions are distributed in an array.
3. The method for preparing a thermally conductive pad according to claim 1, characterized in that: The chemical vapor deposition method comprises first introducing a reducing gas, then introducing a mixed gas including a carbon source gas and an inert gas, and maintaining the temperature at 600° C. to 800° C. for 30 minutes to 300 minutes.
4. The method for preparing a thermally conductive gasket according to claim 1, characterized in that: Before the catalyst is arranged in the first region and the second region, the roughness of the first surface and the second surface is increased by surface treatment.
5. The method for preparing a thermally conductive pad according to claim 1, characterized in that: The method of setting the catalyst in multiple first regions and / or setting the catalyst in multiple second regions includes: covering the first surface and / or the second surface with a mask, then setting the catalyst on the first surface and / or the second surface, and finally removing the mask on the first surface and / or the second surface.
6. The method for preparing a thermally conductive pad according to claim 1, characterized in that: The catalyst includes a solution containing iron ions; Optionally, the catalyst comprises a ferric nitrate solution; Optionally, the concentration of iron ions in the catalyst is 1 mol / L to 2 mol / L.
7. The method for preparing a thermally conductive gasket according to claim 1, characterized in that: The thickness of the first heat-conducting film and / or the second heat-conducting film is 10 μm to 1000 μm; Optionally, the first heat-conducting film and / or the second heat-conducting film has a thickness of 30 μm to 100 μm.
8. The method for preparing a thermally conductive gasket according to claim 1, characterized in that: The distance between the first heat-conducting film and the second heat-conducting film is 50 μm to 1000 μm; Optionally, a distance between the first heat-conducting film and the second heat-conducting film is 50 μm to 500 μm.
9. The method for preparing a thermally conductive gasket according to claim 1, characterized in that: The first heat-conducting film and / or the second heat-conducting film includes a graphene film or a boron nitride film.
10. A thermally conductive pad, characterized in that: The thermally conductive gasket is prepared according to the method for preparing a thermally conductive gasket according to any one of claims 1 to 9.