High-thermal-conductivity graphene heat spreading plate and preparation method thereof

Abstract

The application relates to the technical field of heat management materials, and particularly discloses a high-thermal-conductivity graphene heat spreading plate and a preparation method thereof. The preparation method comprises the following steps: adding 80-90 parts of modified graphene into anhydrous ethanol to prepare a suspension after oscillation, adding 5-8 parts of 20-100 nm doped titanium into the suspension, spraying the mixture on a metal substrate after oscillation and mixing, peeling off in water, and reducing at 2000-2500 DEG C to form a graphene layer; mixing 2-7 parts of modified carbon nanotubes, 2-7 parts of silicon nitride ultra-thin sheets and the graphene layer in ethanol, and mechanically pressing and forming at 150-200 DEG C to obtain a graphene heat spreading plate; wherein the modified graphene is obtained by carbonization reduction of nematic liquid crystal modification of graphene oxide; the modified carbon nanotube is obtained by modification of a nematic liquid crystal modifier on a carbon nanotube; the thickness of the silicon nitride ultra-thin sheet is 1-10 nm; and the doped titanium is formed by vaporization and penetration of titanium particles with a particle size of 20-200 mu m at 1800-2800 DEG C. The graphene heat spreading plate prepared by the method has excellent heat conduction efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of heat management materials, and particularly relates to a high-thermal-conductivity graphene heat spreading plate and a preparation method thereof. BACKGROUND

[0002] Electronic products usually release a large amount of heat when working, and the excess heat will seriously affect the performance and service life of the electronic products if it cannot be diffused in time; in order to diffuse the excess heat in time and efficiently, a heat spreading plate is usually used to diffuse the excess heat.

[0003] The heat spreading plate is usually made of thermal interface materials (TIMs), but the conventional TIMs are generally composed of polymers and thermal conductive fillers, and the in-plane thermal conductivity is low, and the heat spreading effect is limited; the heat spreading plate made of the thermal interface materials (TIMs) has to be improved in terms of heat conduction efficiency.

[0004] Therefore, there is an urgent need for a heat spreading plate with higher heat conduction efficiency. SUMMARY

[0005] In view of the deficiencies in the prior art, the purpose of the present application is to provide a high-thermal-conductivity graphene heat spreading plate and a preparation method thereof.

[0006] In order to achieve the above-mentioned purpose, the present application specifically adopts the following technical solutions:

[0007] A high-thermal-conductivity graphene heat spreading plate and a preparation method thereof, comprising the following steps:

[0008] 80-90 parts by weight of modified graphene is added to anhydrous ethanol to prepare a suspension after oscillation, and then 5-8 parts of 20-100 nm doped titanium is added to the suspension, mixed after oscillation, and sprayed on a metal substrate; after peeling off in water, a graphene layer is formed by reduction at 2000-2500 DEG C;

[0009] 2-7 parts of modified carbon nanotubes, 2-7 parts of silicon nitride ultra-thin sheets and the graphene layer are mixed in ethanol, and mechanically pressed at 150-200 DEG C to obtain a graphene heat spreading plate;

[0010] The modified graphene is obtained by carbonization reduction of graphene oxide modified by nematic liquid crystal;

[0011] The modified carbon nanotubes are obtained by modifying carbon nanotubes with nematic liquid crystal modifier;

[0012] The thickness of the silicon nitride ultra-thin sheet is 1-10 nm;

[0013] The doped titanium is formed by vaporization and penetration of titanium particles with a particle size of 20-200 microns at 1800-2800 DEG C.

[0014] Further, the modified graphene is prepared by mixing the graphene oxide and the nematic liquid crystal in a mass ratio of 1:(1-1.5), stirring at 40-50 DEG C, and drying at 60-70 DEG C to obtain the modified graphene.

[0015] The nematic liquid crystal comprises two of liquid crystal modifier A, liquid crystal modifier B, and liquid crystal modifier C, and the addition weight ratio is 1:1.

[0016] The molecular formula of the liquid crystal modifier A is as follows:

[0017]

[0018] The molecular formula of the liquid crystal modifier B is as follows:

[0019]

[0020] The molecular formula of the liquid crystal modifier C is as follows:

[0021]

[0022] Further, the modified carbon nanotube is prepared by mixing the carbon nanotube and the nematic liquid crystal modifier in a weight ratio of 1:(5-10), heating at 40-80 DEG C for 1-2 h, and ultrasonic oscillation for 10-20 h to obtain the modified carbon nanotube.

[0023] The nematic liquid crystal modifier is the liquid crystal modifier A, and the molecular formula of the liquid crystal modifier A is as follows:

[0024]

[0025] Further, the carbon nanotube has a tube diameter of 35-45 nm, a length of 0.5-2 mu m, and a thermal conductivity of 1500-2500 W / (m.K).

[0026] Further, the modified graphene has a thickness of 1-5 mu m, a density of 2.0-5.5 g / cm 3 , and a thermal conductivity of 1000-3500 W / (m.K).

[0027] Further, the silicon nitride ultra-thin sheet has a thermal conductivity of 500-1000 W / (m.K), and is a circular sheet with a diameter of 1-8 mu m.

[0028] Further, the micron titanium particle has a density of 4.5 g / cm 3 , and a thermal conductivity of 15-20 W / (m.K).

[0029] A high-thermal-conductivity graphene heat spreading plate is prepared by the preparation method of the high-thermal-conductivity graphene heat spreading plate.

[0030] Compared with the prior art, the present application has the following technical effects:

[0031] The modified carbon nanotubes, silicon nitride ultra-thin sheets and micron titanium powder are embedded between the modified graphene in the sintering process, a high-density graphene three-dimensional network structure is constructed, the heat conduction efficiency of the graphene heat spreading plate in the longitudinal and vertical directions is enhanced, and the efficient heat dissipation problem of the graphene heat spreading material in the three-dimensional direction is solved.

[0032] The modified graphene used in the raw material is obtained by carbonization and reduction of graphene oxide modified by nematic liquid crystal, in the process of sintering the modified graphene at high temperature, the modification of the graphene oxide with high orientation degree is realized, and the heat conduction efficiency in the orientation direction of the graphene oxide is enhanced, wherein the graphene heat spreading plate can enhance the heat conduction efficiency of the graphene heat spreading plate in the plane perpendicular to the orientation direction. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 The figure is a structural schematic diagram of the graphene heat spreading plate in embodiment 1 of the present application.

[0034] Figure 2 The figure is a tensile test diagram of the graphene heat spreading plate in embodiments 1-3 and comparative examples 1-3 of the present application. DETAILED DESCRIPTION

[0035] The specific content of the present application is further explained and described in detail in combination with the embodiments.

[0036] The CAS number of the titanium-doped used in the present application is 25583-20-4.

[0037] Preparation example of modified graphene

[0038] Preparation example 1

[0039] A preparation method of modified graphene, comprising the following steps:.

[0040] Mixing the graphene oxide and the nematic liquid crystal with a mass ratio of 1:1, stirring at 40 DEG C for 48 min, and then drying in a drying oven at 60 DEG C for 5 h to obtain the modified graphene.

[0041] The nematic liquid crystal is composed of liquid crystal modifier A and liquid crystal modifier B with a weight ratio of 1:1.

[0042] Preparation example 2

[0043] A preparation method of modified graphene, comprising the following steps:.

[0044] Mixing graphene oxide and nematic liquid crystal with mass ratio of 1:1.2, after stirring for 60 min at 45℃, drying in drying oven at 65℃ for 3h to obtain modified graphene;

[0045] The nematic liquid crystal is composed of liquid crystal modifier A and liquid crystal modifier C with weight ratio of 1:1.

[0046] Preparation Example 3

[0047] A preparation method of modified graphene, comprising the following steps:

[0048] Mixing graphene oxide and nematic liquid crystal with mass ratio of 1:1.5, after stirring for 72 min at 50℃, drying in drying oven at 70℃ for 0.5h to obtain modified graphene;

[0049] The nematic liquid crystal is composed of liquid crystal modifier B and liquid crystal modifier C with weight ratio of 1:1.

[0050] Preparation Example of modified carbon nanotube

[0051] Preparation Example 4

[0052] A preparation method of modified carbon nanotube, comprising the following steps: mixing carbon nanotube and nematic liquid crystal modifier with weight ratio of 1:5, then heating at 40℃ for 1-2h, and ultrasonic oscillation for 10-20h to obtain modified carbon nanotube.

[0053] Preparation Example 5

[0054] A preparation method of modified carbon nanotube, comprising the following steps: mixing carbon nanotube and nematic liquid crystal modifier with weight ratio of 1:8, then heating at 40-80℃ for 1-2h, and ultrasonic oscillation for 10-20h to obtain modified carbon nanotube.

[0055] Preparation Example 6

[0056] A preparation method of modified carbon nanotube, comprising the following steps: mixing carbon nanotube and nematic liquid crystal modifier with weight ratio of 1:10, then heating at 80℃ for 2h, and ultrasonic oscillation for 20h to obtain modified carbon nanotube.

[0057] Example

[0058] Example 1

[0059] A preparation method of high-thermal-conductivity graphene heat spreading plate, comprising the following steps:

[0060] A suspension was prepared by adding 80 parts by weight of the modified graphene prepared by the method in Preparation Example 1 into anhydrous ethanol and shaking for 5 hours, and then 5 parts of titanium doping was added into the suspension, and the mixture was shaken for 5 hours, and then electrostatic spraying was performed on a metal substrate, and after peeling in water, a graphene layer was formed by reduction at 2000°C.

[0061] A graphene heat spreading plate was prepared by mixing 2 parts of the modified carbon nanotube prepared by the method in Preparation Example 4, 2 parts of silicon nitride ultra-thin sheet, and graphene layer, and mechanically pressing at 150°C.

[0062] Example 2

[0063] A method for preparing a high-thermal-conductivity graphene heat spreading plate, comprising the following steps:

[0064] A suspension was prepared by adding 85 parts by weight of the modified graphene prepared by the method in Preparation Example 2 into anhydrous ethanol and shaking for 5 hours, and then 7 parts of titanium doping was added into the suspension, and the mixture was shaken for 5 hours, and then electrostatic spraying was performed on a metal substrate, and after peeling in water, a graphene layer was formed by reduction at 2300°C.

[0065] A graphene heat spreading plate was prepared by mixing 3 parts of the modified carbon nanotube prepared by the method in Preparation Example 5, 3 parts of silicon nitride ultra-thin sheet, and graphene layer, and mechanically pressing at 180°C.

[0066] Example 3

[0067] A method for preparing a high-thermal-conductivity graphene heat spreading plate, comprising the following steps:

[0068] A suspension was prepared by adding 90 parts by weight of the modified graphene prepared by the method in Preparation Example 3 into anhydrous ethanol and shaking for 5 hours, and then 8 parts of titanium doping was added into the suspension, and the mixture was shaken for 5 hours, and then electrostatic spraying was performed on a metal substrate, and after peeling in water, a graphene layer was formed by reduction at 2500°C.

[0069] A graphene heat spreading plate was prepared by mixing 7 parts of the modified carbon nanotube prepared by the method in Preparation Example 6, 7 parts of silicon nitride ultra-thin sheet, and graphene layer, and mechanically pressing at 200°C.

[0070] Comparative Example

[0071] Comparative Example 1

[0072] A method for preparing a high-thermal-conductivity graphene heat spreading plate, according to the method in Example 1, except that the modified graphene in the raw material was replaced by graphene oxide.

[0073] Comparative Example 2

[0074] A method for preparing a high thermal conductivity graphene heat spreader plate is carried out according to the method in Example 1, except that no titanium dopant is added to the raw materials.

[0075] Comparative Example 3

[0076] A method for preparing a high thermal conductivity graphene heat spreader plate is carried out according to the method in Example 1, except that the silicon nitride ultrathin sheets in the raw materials are replaced by modified carbon nanotubes by weight.

[0077] Performance testing

[0078] The brazing rate, tensile strength, tensile modulus, operating temperature range, surface thermal conductivity, longitudinal thermal conductivity, and heat flux of the above embodiments and comparative examples were tested, and the test results are shown in Table 1.

[0079] Table 1:

[0080]

[0081]

[0082] As can be seen from Table 1, the surface thermal conductivity, longitudinal thermal conductivity, and heat flux of the graphene heat spreader in Examples 1-3 of the present invention are all much greater than those of the graphene heat spreader in Comparative Examples 1-3. This indicates that the graphene heat spreader prepared by the preparation method of the present invention has higher thermal conductivity.

[0083] at the same time, Figure 1 This is a schematic diagram of the graphene heat spreader plate in Example 1. Figure 1 As can be seen, the graphene heat spreader plate prepared by the method of the present invention is a dense plate with a high-density three-dimensional graphene network structure inside. This structure can effectively enhance the heat conduction efficiency of the graphene heat spreader plate in the longitudinal and vertical directions, and solve the problem of efficient heat dissipation of graphene heat dissipation materials in the three-dimensional direction. Figure 2 These are tensile test diagrams of the graphene heat spreader plates in Examples 1-3 and Comparative Examples 1-3 of the present invention. Figure 1 It can be seen that, compared with comparative examples 1-3, the tensile stresses of embodiments 1-3 of the present invention are 85MPa, 92MPa, and 96MPa, which are significantly higher than those of comparative examples 1-3; indicating that the graphene heat expansion plate in the present invention effectively improves the tensile strength for better application.

Claims

1. A method for preparing a high thermal conductivity graphene heat spreader, characterized in that: Includes the following steps: A suspension was prepared by adding 80-90 parts by weight of modified graphene to anhydrous ethanol and shaking. Then, 5-8 parts of 20-100 nm doped titanium were added to the suspension, shaken and mixed, and then sprayed onto a metal substrate. After being peeled off in water, the graphene layer was reduced at 2000-2500℃. 2-7 parts of modified carbon nanotubes, 2-7 parts of silicon nitride ultrathin sheets and graphene layers are mixed in ethanol and mechanically pressed at 150-200℃ to obtain a graphene heat spreader plate. The modified graphene is obtained by modifying graphene oxide with nematic liquid crystal. The modified carbon nanotubes are obtained by modifying carbon nanotubes with a nematic liquid crystal modifier; The thickness of the silicon nitride ultrathin sheet is 1~10nm; The doped titanium is formed by vaporization and infiltration of titanium particles with a particle size of 20~200μm at 1800~2800℃; The modified graphene was prepared by the following method: graphene oxide and nematic liquid crystal were mixed in a mass ratio of 1:(1~1.5), stirred at 40~50°C, and dried at 60~70°C to obtain modified graphene. The nematic liquid crystal includes two of liquid crystal modifiers A, B, and C, and the weight ratio of the added modifiers is 1:

1. The molecular formula of the liquid crystal modifier A is as follows: ； The molecular formula of the liquid crystal modifier B is as follows: ； The molecular formula of the liquid crystal modifier C is as follows: 。 2. The method for preparing a high thermal conductivity graphene heat spreader plate as described in claim 1, characterized in that, The modified carbon nanotubes are prepared by the following method: carbon nanotubes and nematic liquid crystal modifiers are mixed in a weight ratio of 1:(5~10), then heated at 40~80℃ for 1~2h, and ultrasonically vibrated for 10~20h to obtain modified carbon nanotubes. The nematic liquid crystal modifier is liquid crystal modifier A, and the molecular formula of liquid crystal modifier A is as follows: 。 3. The method for preparing a high thermal conductivity graphene heat spreader plate as described in claim 2, characterized in that, The carbon nanotubes have a diameter of 35-45 nm, a length of 0.5-2 μm, and a thermal conductivity of 1500-2500 W / (m·K).

4. The method for preparing a high thermal conductivity graphene heat spreader plate as described in claim 1, characterized in that, The modified graphene has a thickness of 1-5 μm and a density of 2.0-5.5 g / cm³. 3 Its thermal conductivity is 1000~3500W / (m·K).

5. The method for preparing a high thermal conductivity graphene heat spreader plate as described in claim 1, characterized in that, The silicon nitride ultrathin sheet has a thermal conductivity of 500~1000W / (m·K) and is a circular sheet with a diameter of 1~8μm.

6. The method for preparing a high thermal conductivity graphene heat spreader plate as described in claim 1, characterized in that, The density of the micron-sized titanium particles is 4.5 g / cm³. 3 Its thermal conductivity is 15~20 W / (m·K).

7. A high thermal conductivity graphene heat spreader plate, characterized in that: It is prepared by the method for preparing a high thermal conductivity graphene heat spreader as described in any one of claims 1-6.

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