CN116162445A - Heat-conducting composite material and preparation method and application thereof - Google Patents

Heat-conducting composite material and preparation method and application thereof Download PDF

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CN116162445A
CN116162445A CN202111547300.8A CN202111547300A CN116162445A CN 116162445 A CN116162445 A CN 116162445A CN 202111547300 A CN202111547300 A CN 202111547300A CN 116162445 A CN116162445 A CN 116162445A
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silicon carbide
chemical vapor
diamond
composite material
deposition
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虞锦洪
秦越
易剑
褚伍波
江南
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Ningbo Hangzhou Bay New Materials Research Institute
Ningbo Institute of Material Technology and Engineering of CAS
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Ningbo Hangzhou Bay New Materials Research Institute
Ningbo Institute of Material Technology and Engineering of CAS
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    • C09K5/00—Heat-transfer, heat-exchange or heat-storage materials, e.g. refrigerants; Materials for the production of heat or cold by chemical reactions other than by combustion
    • C09K5/08—Materials not undergoing a change of physical state when used
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
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    • C08K3/00—Use of inorganic substances as compounding ingredients
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/34—Silicon-containing compounds
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K9/00—Use of pretreated ingredients
    • C08K9/10—Encapsulated ingredients
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K2201/00—Specific properties of additives
    • C08K2201/002—Physical properties
    • C08K2201/005—Additives being defined by their particle size in general
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K2201/00—Specific properties of additives
    • C08K2201/011—Nanostructured additives

Abstract

The application discloses a heat-conducting composite material, a preparation method and application. The thermally conductive composite material includes silicon carbide nanowires and spherical and/or spheroidal diamond deposited on the silicon carbide nanowires. The diamond is arranged on the silicon carbide nano wire in a spherical or sphere-like shape to form a sugar-like calabash structure. The composite material with the looks can not be agglomerated in the polymer and has good heat conduction performance; and contains a composite thermal interface material formed from the composite material and a high molecular polymer, the thermal conductivity of which is easy to reach the percolation threshold.

Description

Heat-conducting composite material and preparation method and application thereof
Technical Field
The application relates to a heat-conducting composite material, a preparation method and application thereof, and belongs to the field of composite materials.
Background
With the advent of fifth generation (5G) mobile communication technology, the enhancement of heat dissipation capability of 5G materials with high power has also faced a great challenge. Development of a novel Thermal Interface Material (TIM) with excellent thermal conductivity is an effective approach to solve the heat dissipation problem of 5G electronic devices. The polymer composite material is widely applied to the preparation of TIM due to the advantages of light weight, low cost, simple preparation and the like. However, since the high molecular weight polymer without any filler generally has only about 0.1 to 0.5 W.multidot.m -1 ·K -1 The thermal conductivity of the material is far from meeting the requirement of heat dissipation capability required in TIM application, and adding high-thermal-conductivity filler into high-molecular polymer is an effective way for improving the thermal conductivity of the high-molecular composite material.
Diamond with excellent electrical insulation property and 2000 W.m -1 ·K -1 The ultra-high thermal conductivity of (C) becomes a filler with prospect for preparing polymer composite materials. However, the use of diamond as a filler to prepare polymeric composites has several problems. First, diamond fillers may agglomerate in the polymer, resulting in a decrease in heat transfer capacity; secondly, higher interface thermal resistance exists between the diamond and the polymer matrix; in addition, the thermal conductivity of the polymer composite material containing the diamond filler is difficult to achievePercolation threshold. Therefore, it is becoming increasingly important to develop a novel diamond thermally conductive filler.
Disclosure of Invention
According to one aspect of the present application, a thermally conductive composite material is provided that is a novel diamond@silicon carbide nanowire of a sugarcoated haws-like structure. The diamond is arranged on the silicon carbide nano wire in a spherical or sphere-like shape to form a sugar-like calabash structure. The composite material with the looks can not be agglomerated in the polymer and has good heat conduction performance; and contains a composite thermal interface material formed from the composite material and a high molecular polymer, the thermal conductivity of which is easy to reach the percolation threshold.
A thermally conductive composite material comprising silicon carbide nanowires and spherical and/or spheroidal diamond deposited on the silicon carbide nanowires.
Optionally, the shape of the heat-conducting composite material is like a sugarcoated haw. Specifically, spherical and/or spheroidal diamonds are linearly arranged (in a row) on silicon carbide nanowires to form a sugarcoated haws-like shape.
Optionally, the silicon carbide nanowires include 3C-SiC type silicon carbide nanowires, 4H-SiC type silicon carbide nanowires, and 6H-SiC type silicon carbide nanowires.
Optionally, the length L of the silicon carbide nanowire is equal to or less than 10 mu m and equal to or less than 150 mu m;
the diameter of the silicon carbide nanowire is d, and the value range of d is more than or equal to 100nm and less than or equal to 600nm.
Optionally, the diamond has a particle size distribution of 1.5 to 3.0 μm; the average grain diameter of the diamond is 2.0-2.5 mu m.
Alternatively, the length L of the silicon carbide nanowires is independently selected from any value or range of values between any two of 10 μm, 20 μm, 30 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm.
Alternatively, the diameter d of the silicon carbide nanowires is independently selected from any value or range of values between any two of 100nm, 150nm, 200nm, 250nm, 300nm, 350nm, 400nm, 450nm, 500nm, 550nm, 600nm.
Alternatively, the diamond particle size distribution is independently selected from any value or range of values between any two of 1.5 μm, 1.7 μm, 2.0 μm, 2.2 μm, 2.5 μm, 2.7 μm, 3.0 μm.
Alternatively, the average particle size of the diamond is independently selected from any value or range of values between any two of 2.0 μm, 2.1 μm, 2.2 μm, 2.3 μm, 2.4 μm, 2.5 μm.
According to a second aspect of the present application, there is also provided a method of preparing a thermally conductive composite material as claimed in any one of the preceding claims, the method comprising: and performing chemical vapor deposition on the carbon source on the substrate attached with the silicon carbide nanowire to obtain the heat-conducting composite material.
Alternatively, the carbon source is selected from C 1 ～C 5 Alkanes, C 1 ～C 5 At least one of ketones, graphite, carbon fibers, and carbon nanotubes. The carbon source used in the present application to deposit diamond may be methane, graphite, and other carbon-containing substances.
Optionally, the carbon source is selected from at least one of methane, acetone, and graphite.
Specifically, for example, methane, graphite, and the like.
Optionally, the preparation method comprises the following steps:
s100, obtaining a dispersion liquid containing silicon carbide nanowires;
s200, transferring the dispersion liquid onto a substrate, evaporating and removing the solvent;
and S300, depositing a carbon source on the substrate obtained in the step S200 in a plasma chemical vapor deposition mode, and obtaining the heat-conducting composite material.
Alternatively, the solvent of the dispersion in step S100 may be acetone, alcohol or other solvents that are easily evaporated.
The concentration of the silicon carbide nanowires in the dispersion liquid is 0.1g/ml to 1g/ml.
Alternatively, the concentration of silicon carbide nanowires is independently selected from any value or range of values between any two of 0.1g/ml, 0.2g/ml, 0.3g/ml, 0.4g/ml, 0.5g/ml, 0.6g/ml, 0.7g/ml, 0.8g/ml, 0.9g/ml, 1.0 g/ml.
Alternatively, the substrate is a copper plate, a glass plate, a silicon substrate, or the like, and may be in the shape of a cuboid, a cylinder, or other polyhedron.
Optionally, the process conditions of the plasma chemical vapor deposition include:
the carbon-hydrogen mole ratio in the deposition atmosphere is 2.5-10%;
the deposition temperature is 700-1100 ℃;
the deposition pressure is 1.8-8 KPa;
the deposition time is 1-6h.
In the application, the process condition of chemical vapor deposition is critical, and the sugarcoated haws-like morphology can be formed only under the proper process condition.
Specifically, the upper limit of the hydrocarbon molar ratio in the deposition atmosphere is selected from 5%, 7.5% and 10%; the lower limit of the hydrocarbon molar ratio in the deposition atmosphere is selected from 2.5%, 5% and 7.5%.
The upper limit of the deposition temperature is selected from 900 ℃, 1000 ℃ and 1100 ℃; the lower limit of the deposition temperature is selected from 700 ℃, 900 ℃ and 1000 ℃.
The upper limit of the deposition pressure is selected from 2.0KPa, 5.3KPa, 6KPa, 8KPa; the lower limit of the deposition pressure is selected from 1.8KPa, 2.0KPa, 5.3KPa, 6KPa, 8KPa.
The upper limit of the deposition time is selected from 2h, 3h and 6h; the lower limit of the deposition time is selected from 1h, 2h and 3h.
Optionally, the plasma chemical vapor deposition comprises any one of hot filament plasma chemical vapor deposition, direct current plasma chemical vapor deposition, microwave plasma chemical vapor deposition.
Optionally, when hot filament plasma chemical vapor deposition is employed, the process conditions further include:
the power of the hot wire is 4000-4500W;
the distance from the hot wire to the surface of the substrate is 3.5-6 mm.
Specifically, the process conditions matched with hot wire plasma chemical vapor deposition are preferably: the carbon-hydrogen mole ratio in the deposition atmosphere is 8-10%; the deposition temperature is 900-1100 ℃; the deposition pressure is 1.8-2 KPa; the deposition time is 1-3 h.
Optionally, when dc plasma chemical vapor deposition is employed, the process conditions further include:
deposition voltage: 500-800V;
deposition current: 2-6A.
Specifically, the process conditions matched with the direct current plasma chemical vapor deposition are preferably as follows: the carbon-hydrogen mole ratio in the deposition atmosphere is 2-3%; the deposition temperature is 700-900 ℃; the deposition pressure is 5-6 KPa; the deposition time is 5-6 h.
Optionally, when microwave plasma chemical vapor deposition is employed, the process conditions further include:
the microwave power is 1200-1800W.
Specifically, the process conditions matched with the microwave plasma chemical vapor deposition are preferably as follows: the carbon-hydrogen mole ratio in the deposition atmosphere is 7-8%; the deposition temperature is 900-1100 ℃; the deposition pressure is 7-8 KPa; the deposition time is 1-2 h.
According to a third aspect of the present application, there is also provided a thermally conductive filler comprising any one of the thermally conductive composite material described in any one of the above, the thermally conductive composite material obtained by any one of the above preparation methods.
Specifically, the invention provides a preparation method of a novel diamond@silicon carbide nanowire composite material with a sugar-like calabash structure, which can be used as a heat conducting filler and belongs to the field of heat conducting composite materials. Firstly, silicon carbide nanowires are dispersed on a substrate through a solvent, then the substrate is placed in a cavity of Chemical Vapor Deposition (CVD) equipment, and diamond is deposited under certain conditions, so that a sugar-like calabash-shaped diamond@silicon carbide nanowire composite material is formed, and the novel filler for manufacturing a polymer composite material is formed.
Optionally, the heat-conducting filler is any one of the heat-conducting composite material described in any one of the above, and the heat-conducting composite material obtained by the preparation method described in any one of the above.
According to a fourth aspect of the present application, there is also provided a thermal interface material comprising a high molecular polymer and the thermally conductive filler described above.
Optionally, the heat conducting filler accounts for 0.01-95 wt% of the high molecular polymer.
Specifically, the proportion relation between the high molecular polymer and the heat conducting filler is that the proportion of the heat conducting filler in the high molecular polymer is 0.01-95 wt%.
Specifically, the high molecular polymer in the thermal interface material formed with the heat conductive filler in the present application may be a high molecular polymer commonly used in the art, such as epoxy resin, polyvinylidene fluoride (PVDF), polydimethylsiloxane (PDMS), polyvinyl alcohol (PVA), and the like.
According to a fifth aspect of the present application, there is also provided the use of the above-mentioned thermally conductive filler and/or the above-mentioned thermal interface material in the field of 5G mobile communication.
The beneficial effects that this application can produce include:
the heat-conducting composite material provided by the application is a novel diamond@silicon carbide nanowire with a sugar-like calabash structure. Namely diamond is inserted on the silicon carbide nanowire in a spherical or sphere-like shape to form a sugar-like gourd structure. The composite material with the looks can not be agglomerated in the polymer and has good heat conduction performance; and contains a composite thermal interface material formed from the composite material and a high molecular polymer, the thermal conductivity of which is easy to reach the percolation threshold.
Drawings
FIG. 1 is an SEM image of the structure of a diamond@SiC nanowire of a sugar-like calabash shape prepared in example 1 of the present application, wherein (a) is an SEM image at a 10 μm scale, and (b) is an SEM image at a 2 μm scale;
FIG. 2 is a graph showing the results of a diamond particle size test in a diamond-like carbon nanowire structure of the sugarcoated haw-like shape prepared in example 1 of the present application;
fig. 3 is a raman spectrum of the deposited diamond particles of example 1 of the present application.
Fig. 4 is an SEM image of the diamond @ silicon carbide nanowire prepared in comparative example 1, with (a) being an SEM image at a 10 μm scale and (b) being an SEM image at a4 μm scale.
Fig. 5 is an SEM image of the diamond @ silicon carbide nanowire prepared in comparative example 2, with (a) being an SEM image at a 10 μm scale and (b) being an SEM image at a 2 μm scale.
Fig. 6 is a raman spectrum of the deposited diamond particles of comparative example 3.
Fig. 7 is a graph showing a morphology test of a thermal interface material obtained by mixing diamond @ silicon carbide nanowires as a filler and a high polymer PDMS in example 1, in which (a) is an SEM image at 8 μm scale and (b) is an SEM image at 2 μm scale.
Fig. 8 is a thermal conductivity test chart of a thermal interface material obtained by mixing diamond @ silicon carbide nanowires as a filler and a high molecular polymer PDMS in example 1.
Detailed Description
The present application is described in detail below with reference to examples, but the present application is not limited to these examples.
Unless otherwise indicated, all starting materials in the examples of the present application were purchased commercially.
Possible embodiments are described below:
the invention provides a method for preparing a novel diamond@silicon carbide nanowire filler with a sugar-like calabash structure, and belongs to the field of heat-conducting composite materials.
The technical scheme of the invention is as follows:
the preparation method of the heat-conducting composite material filler of diamond@silicon carbide nanowire with a novel sugar-like calabash structure comprises the following steps of firstly dispersing silicon carbide nanowire powder in a solvent, spreading the silicon carbide nanowire powder on a substrate, evaporating the solvent, and then placing the substrate in Chemical Vapor Deposition (CVD) equipment for diamond deposition, so that the diamond@silicon carbide nanowire composite material with the sugar-like calabash structure can be obtained, wherein the steps are as follows:
1) The types of silicon carbide nanowires may be 3C-SiC type silicon carbide nanowires, 4H-SiC type silicon carbide nanowires, and 6H-SiC type silicon carbide nanowires. The length of the adopted silicon carbide nanowire is 10-500 mu m, and the diameter is 100-600nm;
2) The solvent used for dispersing the silicon carbide nanowires can be acetone, alcohol or other solvents easy to evaporate;
3) The adopted substrate is copper plate, glass plate or silicon substrate, etc., and the shape can be cuboid, cylinder or other polyhedron;
4) The CVD apparatus used may be a Hot Filament Chemical Vapor Deposition (HFCVD) apparatus, a Direct Current Chemical Vapor Deposition (DCCVD) apparatus, a microwave chemical vapor deposition (MWCVD) apparatus, and other chemical vapor deposition apparatuses;
5) The silicon carbide nanowires are dispersed in a solvent according to a certain proportion (the proportion is not fixed, so long as the silicon carbide nanowires can be uniformly dispersed), ultrasonic dispersion is carried out for 5-20min, then the obtained solution is uniformly poured on the surface of the selected substrate, and then the solvent is evaporated.
6) After the solvent is evaporated, placing a substrate paved with silicon carbide nanowires in a CVD (chemical vapor deposition) device, forming plasmas through direct current, hot wires, microwaves and the like, and after the conditions required by diamond deposition are met, depositing a carbon source on the surface of the silicon carbide nanowires through energy decomposition of the plasmas to form the diamond@silicon carbide nanowire composite material with a required sugar-like calabash structure;
the carbon source used for depositing diamond can be methane, graphite and other substances containing carbon elements, the ratio of the concentration of carbon to hydrogen in the cavity is 2.5-10%, the pressure in the cavity is 1.8-8kPa, the temperature maintained during deposition is 700-1100 ℃, and the deposition time is 1-6 hours.
In an embodiment, the silicon carbide nanowire powder is purchased from Changsha Siemens New material Co., ltd, and has a length of 50-150 μm and a diameter of 100-600nm.
Example 1:
0.05g of silicon carbide nanowire powder was poured into 10ml of acetone solution, and a suspension was formed after 5min of ultrasound. The resulting suspension was poured uniformly over a 200X 80X 10mm size 3 After the acetone is evaporated, the copper plate paved with the silicon carbide nanowires is placed into an HFCVD cavity. The carbon source is methane. At the position ofThe diamond@silicon carbide nanowire filler with a sugarcoated haw-like structure is successfully prepared under the technological parameters of 10.0% of hydrocarbon ratio, 4000W of hot wire power, 5mm of hot wire-to-copper plate surface distance, 900 ℃ of deposition temperature, 1.8kPa of cavity air pressure and 3 hours of deposition time.
Example 2:
0.05g of silicon carbide nanowire powder was poured into 15ml of an alcohol solution, and a suspension was formed after 20min of ultrasound. The resulting suspension was poured evenly onto a silicon substrate of 100mm diameter and 2mm height, and after evaporation of the alcohol, the silicon substrate with silicon carbide nanowires laid down was placed into a DCCVD chamber. The carbon source is graphite. The diamond@silicon carbide nanowire filler with a sugarcoated haw-like structure is successfully prepared under the technological parameters of 2.5% of hydrocarbon ratio, 600V of voltage, 4A of current, 700 ℃ of deposition temperature, 5.3kPa of cavity air pressure and 6 hours of deposition time.
Example 3:
0.03g of silicon carbide nanowire powder was poured into 12ml of acetone solution, and a suspension was formed after 15min of ultrasound. The resulting suspension was poured uniformly over 200X 80X 10mm 3 After the acetone is evaporated, the copper plate paved with the silicon carbide nanowires is placed into an MWCVD cavity. The carbon source is acetone. The diamond silicon carbide nano filler with the sugar-like calabash structure is successfully prepared under the technological parameters of 7.5 percent of hydrocarbon ratio, 1500W of power, 1000 ℃ of deposition temperature, 8kPa of cavity air pressure and 2 hours of deposition time.
Example 4:
0.05g of silicon carbide nanowire powder was poured into 10ml of an alcohol solution, and a suspension was formed after 20min of ultrasound. The resulting suspension was poured uniformly onto a glass substrate having a diameter of 50mm and a height of 2mm, and after evaporation of the alcohol, the glass substrate with silicon carbide nanowires laid thereon was placed in an HFCVD chamber. The carbon source is methane. The diamond@silicon carbide nanowire filler with a sugarcoated haw-like structure is successfully prepared under the technological parameters of 10.0% of hydrocarbon ratio, 4400W of hot wire power, 5mm of hot wire-copper plate surface distance, 1100 ℃ of deposition temperature, 2.0kPa of cavity air pressure and 1h of deposition time.
Example 5 characterization of morphology
The measuring device was a field emission scanning electron microscope (FE-SEM, S4800, hitachi, japan), and the microscopic morphology of the diamond@silicon carbide nanowires prepared in examples 1 to 4 was observed under an acceleration voltage of 8 kV. The diamond particles can be orderly arranged on the silicon carbide nanowire in a row, and a special novel structure of the sugarcoated haws on a stick is formed.
As typically represented in example 1, as shown in fig. 1, an SEM image of the diamond@silicon carbide nanowire structure of the sugarcoated haw-like structure prepared in example 1, an SEM image of the structure of the sugarcoated haw-like structure was obtained in a 10 μm scale, and an SEM image of the structure of the sugarcoated haw-like structure was obtained in a 2 μm scale, and it was seen that the deposited diamond particles were regularly arranged in a row on the silicon carbide nanowire to form a novel structure of the special sugarcoated haw-like structure.
Example 6 particle size characterization of diamond particles
The measuring equipment is a field emission scanning electron microscope (FE-SEM, S4800, hitachi, japan), the particle size of diamond in the diamond@silicon carbide nanowires prepared in examples 1-4 is tested, the diamond@silicon carbide nanowire in a sugar-like calabash shape prepared in example 1 is taken as a typical example, and FIG. 2 is the particle size test result of diamond in a structure, and the test result shows that the diamond particle size distribution is in the range of 1.5-3.0 μm, and the average value is 2.0-2.5 μm.
Example 7 characterization of substances
The measuring device was a raman spectrometer (inVia-reflex, renishaw, UK) and raman spectroscopic analysis was performed on the diamond@silicon carbide nanowires prepared in examples 1 to 4 with a laser having a wavelength of 532 nm. The characterization result shows that: the obtained substances are all diamond particles.
As typified by example 1, FIG. 3 is a Raman spectrum diagram thereof, from which it can be observed that the Lorentzian peak finding process has been performed at 1140, 1332, 1482 and 1546cm -1 Four peaks, 1332cm -1 The peaks were characteristic peaks of diamond, which also demonstrates that the deposited particles were indeed diamond particles. Located at 1140 and 1482cm -1 The peak of (2) is caused by the grain boundaries of diamond, which usually occur due to nano-scaleThe presence of nanocrystalline diamond. Located at 1546cm -1 Is the G peak of the carbon material.
Comparative example 1
0.05g of silicon carbide nanowire powder was poured into 10ml of an alcohol solution, and a suspension was formed after 20min of ultrasound. The resulting suspension was poured uniformly onto a glass substrate having a diameter of 50mm and a height of 2mm, and after evaporation of the alcohol, the glass substrate with silicon carbide nanowires laid thereon was placed in an HFCVD chamber. The carbon source is methane. Under the technological parameters of 1% of hydrocarbon ratio, 4000W of hot wire power, 5mm of hot wire-to-copper plate surface distance, 1000 ℃ of deposition temperature, 2.0kPa of cavity air pressure and 2 hours of deposition time, diamond@silicon carbide nanowire filler with a sugarcoated haw-like structure cannot be prepared.
Comparative example 2
0.03g of silicon carbide nanowire powder was poured into 12ml of acetone solution, and a suspension was formed after 15min of ultrasound. The resulting suspension was poured uniformly over 200X 80X 10mm 3 After the acetone is evaporated, the copper plate paved with the silicon carbide nanowires is placed into an MWCVD cavity. The carbon source is acetone. Under the technological parameters of 7.5 percent of hydrocarbon ratio, 900W of power, 650 ℃ of deposition temperature, 8kPa of cavity air pressure and 3 hours of deposition time, the diamond silicon carbide nano filler with the sugar-like calabash structure cannot be prepared.
Comparative example 3
0.1g of silicon carbide nanowire powder was poured into 10ml of an alcohol solution, and a suspension was formed after 20min of ultrasound. The resulting suspension was poured uniformly onto a glass substrate having a diameter of 50mm and a height of 2mm, and after evaporation of the alcohol, the glass substrate with silicon carbide nanowires laid thereon was placed in an HFCVD chamber. The carbon source is methane. Under the technological parameters of 15.0 percent of hydrocarbon ratio, 4400W of hot wire power, 5mm of hot wire-to-copper plate surface distance, 1100 ℃ of deposition temperature, 2.0kPa of cavity air pressure and 6 hours of deposition time, the diamond@silicon carbide nanowire filler with the sugar-gourd-like structure cannot be prepared.
The topography test of comparative example 1 was performed, and the test results are shown in fig. 4, in which fig. 4 shows SEM images at a 10 μm scale and fig. 4 shows SEM images at a4 μm scale, and it can be seen that no diamond was formed on the surface of the silicon carbide nanowire.
The morphology test of the comparative example 2 was performed, and the test results are shown in fig. 5, in which fig. 5 shows an SEM image at a 10 μm scale and fig. 5 shows an SEM image at a 2 μm scale, and it can be seen from fig. 5 that diamond particles generated on the surface of the silicon carbide nanowire are too small to form a typical sugar gourd structure.
The deposited diamond particles of comparative example 3 were subjected to raman test, and the test results are shown in fig. 6, and it can be seen from fig. 6 that amorphous diamond, which is a material in which graphite, diamond, and amorphous carbon coexist, is formed on the surface of the silicon carbide nanowire.
Example 8 preparation of thermal interface Material
The diamond@silicon carbide nanowire fillers in examples 1-4 are respectively mixed with a high molecular polymer PDMS, and the mass ratio of the diamond@silicon carbide nanowire fillers to the high molecular polymer PDMS is 5% -80%. Thereby obtaining a thermal interface material.
The obtained thermal interface material is subjected to morphology test respectively, and the test result shows that the diamond@silicon carbide nanowire is not agglomerated in the high molecular polymer.
The thermal interface material formed by the filler in example 1 is typically represented by a mass ratio of the filler to the high molecular polymer of 70%, and the test results are shown in fig. 7, in which fig. 7 (a) is an SEM image at 8 μm scale and fig. 2 μm scale, which shows that the diamond@silicon carbide nanowire filler having a sugar gourd-like structure is well dispersed in PDMS.
The thermal conductivity of the resulting thermal interface materials was tested separately (thermal conductivity λ was represented by the formula λ=α×c p X ρ, where α is the thermal diffusivity, measured by a flash thermal conductivity meter (LFA 467
Figure BDA0003416102410000111
NETZSCH, germany), C p As specific heat capacity, ρ as density), the test result shows that the thermal conductivity of the obtained thermal interface material is 0.2-2W m -1 K -1 。
Typically, the thermal interface material formed by the filler of example 1 is as followsFIG. 8 shows a thermal conductivity of 0.57W m -1 K -1 。
The foregoing description is only a few examples of the present application and is not intended to limit the present application in any way, and although the present application is disclosed in the preferred examples, it is not intended to limit the present application, and any person skilled in the art may make some changes or modifications to the disclosed technology without departing from the scope of the technical solution of the present application, and the technical solution is equivalent to the equivalent embodiments.

Claims (10)

1. A thermally conductive composite material comprising silicon carbide nanowires and spherical and/or spheroidal diamond deposited on the silicon carbide nanowires.
2. The thermally conductive composite of claim 1, wherein the spherical and/or spheroid-like diamonds are arranged on the silicon carbide nanowires to form a sugarcoated haws-like shape.
3. The thermally conductive composite of claim 1, wherein the silicon carbide nanowires comprise 3C-SiC type silicon carbide nanowires, 4H-SiC type silicon carbide nanowires, or 6H-SiC type silicon carbide nanowires;
preferably, the length of the silicon carbide nanowire is L, and the value range of L is more than or equal to 10 mu m and less than or equal to 150 mu m;
the diameter of the silicon carbide nanowire is d, and the value range of d is more than or equal to 100nm and less than or equal to 600nm;
preferably, the diamond has a particle size distribution of 1.5 to 3.0 μm; the average grain diameter of the diamond is 2.0-2.5 mu m.
4. A method of preparing a thermally conductive composite material as claimed in any one of claims 1 to 3, wherein the method of preparing comprises:
and performing chemical vapor deposition on the carbon source on the substrate attached with the silicon carbide nanowire to obtain the heat-conducting composite material.
5. The method according to claim 4, wherein the carbon source is selected from C 1 ～C 5 Alkanes, C 1 ～C 5 At least one of ketones, graphite, carbon fibers, and carbon nanotubes.
6. The preparation method according to claim 4, characterized in that the preparation method comprises:
s100, obtaining a dispersion liquid containing silicon carbide nanowires;
s200, transferring the dispersion liquid onto a substrate, evaporating and removing the solvent;
and S300, depositing a carbon source on the substrate obtained in the step S200 in a plasma chemical vapor deposition mode, and obtaining the heat-conducting composite material.
7. The method of claim 6, wherein the process conditions of the plasma chemical vapor deposition include:
the carbon-hydrogen mole ratio in the deposition atmosphere is 2.5-10%;
the deposition temperature is 700-1100 ℃;
the deposition pressure is 1.8-8 KPa;
the deposition time is 1 to 6 hours;
preferably, the plasma chemical vapor deposition comprises any one of hot filament plasma chemical vapor deposition, direct current plasma chemical vapor deposition and microwave plasma chemical vapor deposition;
preferably, when hot wire plasma chemical vapor deposition is employed, the process conditions further include:
the power of the hot wire is 4000-4500W;
the distance from the hot wire to the surface of the substrate is 3.5-6 mm;
preferably, when direct current plasma chemical vapor deposition is employed, the process conditions further include:
deposition voltage: 500-800V;
deposition current: 2-6A;
preferably, when microwave plasma chemical vapor deposition is employed, the process conditions further include:
the microwave power is 1200-1800W.
8. A heat conductive filler, characterized in that the heat conductive filler comprises any one of the heat conductive composite material according to any one of claims 1 to 3, the heat conductive composite material obtained by the production method according to any one of claims 4 to 7.
9. A thermal interface material comprising a high molecular polymer and the thermally conductive filler of claim 8.
10. Use of the thermally conductive filler of claim 8 and/or the thermal interface material of claim 9 in the field of 5G mobile communications.
CN202111547300.8A 2021-11-24 2021-12-16 Heat-conducting composite material and preparation method and application thereof Pending CN116162445A (en)

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CN2021114069604 2021-11-24

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CN116162445A true CN116162445A (en) 2023-05-26

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