Preparation method of graphene copper-based reinforced heat-conducting film

Abstract

The application discloses a preparation method of a graphene copper-based reinforced heat-conducting film, and comprises the following steps: (1) foam copper powder pretreatment; (2) chemical deposition of graphene on the pretreated foam copper powder to obtain graphene composite foam copper powder; (3) mixing the graphene composite foam copper powder with foam graphene powder, adding graphene / pure copper mixed powder, and ball milling; (4) copper evaporation of the obtained mixture; (5) uniformly mixing the mixture obtained in the step (4), laying the mixture on the bottom of a plane mold, covering the upper surface with a copper foil, and casting copper liquid under oscillation conditions; (6) and mold, programmed cooling under vacuum oscillation conditions, to obtain the graphene copper-based reinforced heat-conducting film. The heat-dissipating film prepared by the method provided by the application does not involve an electroplating process, has low energy consumption, is environment-friendly, has a relatively stable heat-conducting film structure, high strength, excellent mechanical properties, high controllability of film size, and stable mechanical and electrical properties when the size is increased, and is suitable for various fields.

Description

Technical Field

[0001] This invention relates to the field of thermally conductive composite material preparation technology, specifically to a method for preparing a graphene copper-based reinforced thermally conductive film. Background Technology

[0002] In recent years, with the rapid rise of the electronics industry, especially the rapid development of the mobile phone industry, there have been higher requirements for the performance of components, especially those that have a huge impact on the intelligence, configuration, computing speed, and CPU frequency of mobile phones. Among these performance requirements, due to the multitasking and high-performance requirements of mobile phones, heat generation is difficult to avoid when the phone is running at high speed. Therefore, the thermal performance of components, especially their thermal conductivity and heat dissipation performance, has become more important.

[0003] Currently, graphite thermal conductive films or metal sheets remain common heat dissipation technologies in mobile phone technology. By contacting these heat-conducting films with heat-generating components, heat is absorbed and conducted to achieve heat dissipation, thereby reducing the temperature of operating components and improving mobile phone performance. However, with further improvements in mobile phone performance, these simple thermal conductive materials are gradually becoming insufficient to meet the performance requirements, leading to the development of composite materials that better meet production and usage requirements.

[0004] Graphene-copper composites have also attracted attention during this period. Since both pure copper and graphene possess excellent electrical properties, and graphene also has superior mechanical properties, researchers strive to combine their advantages through specific composite technologies to prepare composite thermally conductive films with excellent electrical and mechanical properties. However, current methods for obtaining such composite thermally conductive films mainly focus on electroplating. While these methods produce products with uniform composite material distribution, they suffer from poor mechanical properties. Especially as the thickness of the thermally conductive film increases, its strength no longer meets production requirements, and its thermal conductivity also significantly decreases. Furthermore, these methods also involve high energy consumption and environmental pollution. Other methods, such as preparing the composite material first and then hot-pressing and sintering, generally suffer from the inability to flexibly control the film thickness, or the film thickness having a significant impact on material properties, making large-scale production applications impossible. Summary of the Invention

[0005] To address the above problems, this invention provides a method for preparing a graphene copper-based enhanced thermally conductive film, comprising the following steps:

[0006] (1) Take copper foam powder and pretreat it;

[0007] (2) Graphene was chemically deposited onto the pretreated copper foam powder to obtain graphene composite copper foam powder.

[0008] (3) Mix the graphene composite foamed copper powder obtained in step (2) with the foamed graphene powder, add the graphene / pure copper mixed powder, and ball mill;

[0009] (4) Copper is vapor-deposited into the mixture obtained in step (3);

[0010] (5) After mixing the mixture obtained in step (4), spread it evenly on the bottom of the flat mold, cover the upper surface with copper foil, and cast copper liquid under vibration conditions;

[0011] (6) The graphene copper-based enhanced thermal conductive film was obtained by cooling the film under vacuum oscillation conditions.

[0012] Preferably, the copper foam powder in step (1) has a porosity of 70-85% and a particle size of 38-74 μm.

[0013] Preferably, the pretreatment in step (1) specifically includes: placing the copper foam in deionized water, sonicating for 10-30 minutes, taking it out and placing it in ethanol, sonicating for 10-30 minutes, taking it out and placing it in acetone, sonicating for 10-30 minutes.

[0014] Preferably, the specific conditions for the chemical deposition of graphene in step (2) include: annealing in a hydrogen atmosphere: the atmosphere is hydrogen, the hydrogen gas flow rate is 15 sccm-25 sccm; the pressure is 100 Pa; the temperature is 700-850 ℃, and the time is 5-8 min; chemical deposition: the atmosphere is methane, the methane gas flow rate is 10 sccm-30 sccm; the deposition pressure is 100 Pa; the deposition temperature is 700-850 ℃; and the deposition time is 5 min-20 min.

[0015] Preferably, the foamed graphene powder in step (3) has a foam pore size of 0.005-0.1 mm, an open porosity of 40-99.9%, and a powder particle size of 38-74 μm.

[0016] Preferably, the mass ratio of the graphene composite copper foam powder obtained in step (2) to the graphene foam powder in step (3) is (1.7-9.2):1.

[0017] Preferably, the mass ratio of the graphene composite foam copper powder obtained in step (2) to the graphene / pure copper mixed powder in step (3) is (1.7-9.2):(0.3-4.9).

[0018] Preferably, in the graphene / pure copper mixed powder in step (3), the particle size of both is 3-20 μm, and the mass ratio of graphene powder to pure copper powder is (1.1-3.7):1.

[0019] Preferably, the ball milling in step (3) is dry ball milling, and the ball milling time is 10-30 min.

[0020] Preferably, the copper vapor deposition in step (4) is performed under the following conditions: a vacuum degree of 5 × 10⁻⁶. -4 For pressures below Pa, the evaporation current is 100A-120A, and the evaporation time is 1s-30s.

[0021] Preferably, the copper foil in step (5) has a thickness of 20-600 μm.

[0022] Preferably, the mixture obtained in step (4) in step (5) has a thickness of 40-1000 μm after being mixed evenly.

[0023] Preferably, in step (5), a gap is left between the copper foil and the side wall of the mold, and the gap width is 0.3-0.8 mm.

[0024] Preferably, the temperature of the copper liquid in step (5) is 1090-1150℃, and more preferably 1125℃.

[0025] Preferably, the volume ratio of the copper liquid in step (5) to the mixture obtained in step (4) is (0.2-3.1):1, and the casting process is based on the copper liquid filling the gaps in the powder below the copper foil after the vacuum oscillation is completed.

[0026] Preferably, the vacuum in step (6) has a pressure of 4-10 Pa.

[0027] Preferably, the programmed cooling in step (6) includes: first cooling to 450°C at a rate of 200-400°C / min, and then naturally cooling to room temperature.

[0028] Beneficial effects

[0029] The beneficial effects of this invention are as follows:

[0030] (1) The method for preparing graphene copper-based enhanced thermal conductive film provided by the present invention does not involve electroplating, has relatively low energy consumption, low equipment requirements, generates few pollutants during the process, and is environmentally friendly;

[0031] (2) The graphene copper-based enhanced thermal conductive film prepared by the method provided in this invention has a relatively complex three-dimensional structure, stable structure, high strength, and all mechanical properties are superior to those of the graphene copper-based enhanced thermal conductive film prepared by traditional methods.

[0032] (3) The graphene copper-based enhanced thermal conductive film prepared by the method provided by the present invention has a wide range of controllable film thickness, and the product is applicable to various fields with no limitation on application scope;

[0033] (4) The graphene copper-based enhanced thermal conductive film prepared by the method provided in this invention can maintain very stable mechanical properties and electrical properties that are basically unaffected by thickness when the film thickness decreases or increases. This is very different from the traditional method of preparing graphene copper-based enhanced thermal conductive film. Detailed Implementation

[0034] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0035] Unless otherwise specified, the following examples and comparative examples are parallel experiments, using the same processing steps and parameters.

[0036] Example 1: Preparation of a graphene-copper-based enhanced thermal conductive film:

[0037] (1) Take copper foam powder and pretreat it;

[0038] (2) Graphene was chemically deposited onto the pretreated copper foam powder to obtain graphene composite copper foam powder.

[0039] (3) Mix the graphene composite foamed copper powder obtained in step (2) with the foamed graphene powder, add the graphene / pure copper mixed powder, and ball mill;

[0040] (4) Copper is vapor-deposited into the mixture obtained in step (3);

[0041] (5) After mixing the mixture obtained in step (4), spread it evenly on the bottom of the flat mold, cover the upper surface with copper foil, and cast copper liquid under vibration conditions;

[0042] (6) The graphene copper-based enhanced thermal conductive film was obtained by cooling the film under vacuum oscillation conditions.

[0043] The copper foam powder in step (1) has a porosity of 70-85% and a particle size of 38-45 μm.

[0044] The pretreatment described in step (1) specifically includes: placing the copper foam in deionized water, sonicating for 10 minutes, taking it out and placing it in ethanol, sonicating for 10 minutes, taking it out and placing it in acetone, sonicating for 10 minutes.

[0045] The specific conditions for the chemical deposition of graphene in step (2) include: annealing in a hydrogen atmosphere: the atmosphere is hydrogen, the hydrogen gas flow rate is 15 sccm, the pressure is 100 Pa, the temperature is 700 °C, and the time is 5 min; chemical deposition: the atmosphere is methane, the methane gas flow rate is 10 sccm, the deposition pressure is 100 Pa, the deposition temperature is 700 °C, and the deposition time is 5 min.

[0046] The foamed graphene powder in step (3) has a foam pore size of 0.005-0.1 mm, an open porosity of 40-99.9%, and a powder particle size of 38-45 μm.

[0047] The mass ratio of the graphene composite foam copper powder to the foam graphene powder obtained in step (2) is 1.7:1.

[0048] The mass ratio of the graphene composite foam copper powder obtained in step (2) to the graphene / pure copper mixed powder in step (3) is 1.7:0.3.

[0049] In step (3), the graphene / pure copper mixed powder has a particle size of 3-20 μm, and the mass ratio of graphene powder to pure copper powder is 1.1:1.

[0050] The ball milling in step (3) is a dry ball milling process, and the milling time is 10 minutes.

[0051] The conditions for copper vapor deposition in step (4) include: a vacuum degree of 5 × 10⁻⁶. -4 Below Pa, the evaporation current is 100A and the evaporation time is 10s.

[0052] The copper foil in step (5) has a thickness of 20 μm.

[0053] The mixture obtained in step (4) in step (5) has a thickness of about 80 μm after being mixed evenly.

[0054] In step (5), a gap is left between the copper foil and the side wall of the mold, with a gap width of 0.3-0.8 mm.

[0055] The temperature of the copper liquid in step (5) is 1090℃.

[0056] The volume ratio of the copper liquid in step (5) to the mixture obtained in step (4) is (0.2-3.1):1. The casting process is based on the copper liquid filling the gaps in the powder below the copper foil after the vacuum oscillation is completed.

[0057] The vacuum in step (6) has a pressure of 4 Pa.

[0058] The programmed cooling in step (6) includes: first cooling to 450°C at a rate of 200°C / min, and then cooling naturally to room temperature.

[0059] The resulting finished product has dimensions of 10mm × 10mm × 0.1mm and a film thickness of approximately 100μm.

[0060] Example 2: Preparation of a graphene-copper-based enhanced thermal conductive film:

[0061] (1) Take copper foam powder and pretreat it;

[0062] (2) Graphene was chemically deposited onto the pretreated copper foam powder to obtain graphene composite copper foam powder.

[0063] (3) Mix the graphene composite foamed copper powder obtained in step (2) with the foamed graphene powder, add the graphene / pure copper mixed powder, and ball mill;

[0064] (4) Copper is vapor-deposited into the mixture obtained in step (3);

[0065] (5) After mixing the mixture obtained in step (4), spread it evenly on the bottom of the flat mold, cover the upper surface with copper foil, and cast copper liquid under vibration conditions;

[0066] (6) The graphene copper-based enhanced thermal conductive film was obtained by cooling the film under vacuum oscillation conditions.

[0067] The copper foam powder in step (1) has a porosity of 70-85% and a particle size of 63-74 μm.

[0068] The pretreatment described in step (1) specifically includes: placing the copper foam in deionized water, sonicating for 30 minutes, taking it out and placing it in ethanol, sonicating for 30 minutes, taking it out and placing it in acetone, sonicating for 30 minutes.

[0069] The specific conditions for the chemical deposition of graphene in step (2) include: annealing in a hydrogen atmosphere: the atmosphere is hydrogen, the hydrogen gas flow rate is 25 sccm, the pressure is 100 Pa, the temperature is 850 ℃, and the time is 8 min; chemical deposition: the atmosphere is methane, the methane gas flow rate is 30 sccm, the deposition pressure is 100 Pa, the deposition temperature is 850 ℃, and the deposition time is 20 min.

[0070] The foamed graphene powder in step (3) has a foam pore size of 0.005-0.1 mm, an open porosity of 40-99.9%, and a powder particle size of 63-74 μm.

[0071] The mass ratio of the graphene composite foam copper powder to the foam graphene powder obtained in step (2) is 9.2:1.

[0072] The mass ratio of the graphene composite foam copper powder obtained in step (2) to the graphene / pure copper mixed powder is 9.2:4.9.

[0073] In step (3), the graphene / pure copper mixed powder has a particle size of 3-20 μm, and the mass ratio of graphene powder to pure copper powder is 3.7:1.

[0074] The ball milling in step (3) is a dry ball milling process, and the milling time is 30 minutes.

[0075] The conditions for copper vapor deposition in step (4) include: a vacuum degree of 5 × 10⁻⁶. -4 Below Pa, the evaporation current is 120A and the evaporation time is 30s.

[0076] The copper foil in step (5) has a thickness of 20 μm.

[0077] The mixture obtained in step (4) in step (5) has a thickness of about 80 μm after being mixed evenly.

[0078] In step (5), a gap is left between the copper foil and the side wall of the mold, with a gap width of 0.3-0.8 mm.

[0079] The temperature of the copper liquid in step (5) is 1150℃.

[0080] The volume ratio of the copper liquid in step (5) to the mixture obtained in step (4) is 3.1:1. The casting process is based on the copper liquid filling the gaps in the powder below the copper foil after the vacuum oscillation is completed.

[0081] The vacuum in step (6) has a pressure of 10 Pa.

[0082] Step (6) of the programmed cooling includes: first cooling to 450°C at a rate of 00°C / min, and then naturally cooling to room temperature.

[0083] The resulting finished product has dimensions of 10mm × 10mm × 0.1mm and a film thickness of approximately 100μm.

[0084] Example 3: Preparation of a graphene-copper-based enhanced thermal conductive film:

[0085] (1) Take copper foam powder and pretreat it;

[0086] (2) Graphene was chemically deposited onto the pretreated copper foam powder to obtain graphene composite copper foam powder.

[0087] (3) Mix the graphene composite foamed copper powder obtained in step (2) with the foamed graphene powder, add the graphene / pure copper mixed powder, and ball mill;

[0088] (4) Copper is vapor-deposited into the mixture obtained in step (3);

[0089] (5) After mixing the mixture obtained in step (4), spread it evenly on the bottom of the flat mold, cover the upper surface with copper foil, and cast copper liquid under vibration conditions;

[0090] (6) The graphene copper-based enhanced thermal conductive film was obtained by cooling the film under vacuum oscillation conditions.

[0091] The copper foam powder in step (1) has a porosity of 70-85% and a particle size of 53-63 μm.

[0092] The pretreatment described in step (1) specifically includes: placing the copper foam in deionized water, sonicating for 20 minutes, taking it out and placing it in ethanol, sonicating for 20 minutes, taking it out and placing it in acetone, sonicating for 20 minutes.

[0093] The specific conditions for the chemical deposition of graphene in step (2) include: annealing in a hydrogen atmosphere: the atmosphere is hydrogen, the hydrogen gas flow rate is 20 sccm, the pressure is 100 Pa, the temperature is 750 ℃, and the time is 7 min; chemical deposition: the atmosphere is methane, the methane gas flow rate is 20 sccm, the deposition pressure is 100 Pa, the deposition temperature is 750 ℃, and the deposition time is 15 min.

[0094] The foamed graphene powder in step (3) has a foam pore size of 0.005-0.1 mm, an open porosity of 40-99.9%, and a powder particle size of 53-63 μm.

[0095] The mass ratio of the graphene composite copper foam powder to the graphene foam powder obtained in step (2) is 5.5:1.

[0096] The mass ratio of the graphene composite foam copper powder obtained in step (2) to the graphene / pure copper mixed powder is 5.5:1.

[0097] In step (3), the graphene / pure copper mixed powder has a particle size of 3-20 μm, and the mass ratio of graphene powder to pure copper powder is 2.2:1.

[0098] The ball milling in step (3) is a dry ball milling process, and the milling time is 20 minutes.

[0099] The conditions for copper vapor deposition in step (4) include: a vacuum degree of 5 × 10⁻⁶. -4 Below Pa, the evaporation current is 110A and the evaporation time is 20s.

[0100] The copper foil in step (5) has a thickness of 20 μm.

[0101] The mixture obtained in step (4) in step (5) has a thickness of about 80 μm after being mixed evenly.

[0102] In step (5), a gap is left between the copper foil and the side wall of the mold, with a gap width of 0.3-0.8 mm.

[0103] The temperature of the copper liquid in step (5) is 1125℃.

[0104] The volume ratio of the copper liquid in step (5) to the mixture obtained in step (4) is (0.2-3.1):1. The casting process is based on the copper liquid filling the gaps in the powder below the copper foil after the vacuum oscillation is completed.

[0105] The vacuum in step (6) has a pressure of 7 Pa.

[0106] The programmed cooling in step (6) includes: first cooling to 450°C at a rate of 300°C / min, and then cooling naturally to room temperature.

[0107] The resulting finished product has dimensions of 10mm × 10mm × 0.1mm and a film thickness of approximately 100μm.

[0108] Example 4: Preparation of a graphene-copper-based enhanced thermal conductive film:

[0109] (1) Take copper foam powder and pretreat it;

[0110] (2) Graphene was chemically deposited onto the pretreated copper foam powder to obtain graphene composite copper foam powder.

[0111] (3) Mix the graphene composite foamed copper powder obtained in step (2) with the foamed graphene powder, add the graphene / pure copper mixed powder, and ball mill;

[0112] (4) Copper is vapor-deposited into the mixture obtained in step (3);

[0113] (5) After mixing the mixture obtained in step (4), spread it evenly on the bottom of the flat mold, cover the upper surface with copper foil, and cast copper liquid under vibration conditions;

[0114] (6) The graphene copper-based enhanced thermal conductive film was obtained by cooling the film under vacuum oscillation conditions.

[0115] The copper foam powder in step (1) has a porosity of 70-85% and a particle size of 53-63 μm.

[0116] The pretreatment described in step (1) specifically includes: placing the copper foam in deionized water, sonicating for 20 minutes, taking it out and placing it in ethanol, sonicating for 20 minutes, taking it out and placing it in acetone, sonicating for 20 minutes.

[0117] The specific conditions for the chemical deposition of graphene in step (2) include: annealing in a hydrogen atmosphere: the atmosphere is hydrogen, the hydrogen gas flow rate is 20 sccm, the pressure is 100 Pa, the temperature is 750 ℃, and the time is 7 min; chemical deposition: the atmosphere is methane, the methane gas flow rate is 20 sccm, the deposition pressure is 100 Pa, the deposition temperature is 750 ℃, and the deposition time is 15 min.

[0118] The foamed graphene powder in step (3) has a foam pore size of 0.005-0.1 mm, an open porosity of 40-99.9%, and a powder particle size of 53-63 μm.

[0119] The mass ratio of the graphene composite copper foam powder to the graphene foam powder obtained in step (2) is 5.5:1.

[0120] The mass ratio of the graphene composite foam copper powder obtained in step (2) to the graphene / pure copper mixed powder is 5.5:1.

[0121] In step (3), the graphene / pure copper mixed powder has a particle size of 3-20 μm, and the mass ratio of graphene powder to pure copper powder is 2.2:1.

[0122] The ball milling in step (3) is a dry ball milling process, and the milling time is 20 minutes.

[0123] The conditions for copper vapor deposition in step (4) include: a vacuum degree of 5 × 10⁻⁶. -4 Below Pa, the evaporation current is 110A and the evaporation time is 20s.

[0124] The copper foil in step (5) has a thickness of 100 μm.

[0125] Step (5) The mixture obtained in step (4) is spread evenly to a thickness of about 400 μm.

[0126] In step (5), a gap is left between the copper foil and the side wall of the mold, with a gap width of 0.3-0.8 mm.

[0127] The temperature of the copper liquid in step (5) is 1125℃.

[0128] The volume ratio of the copper liquid in step (5) to the mixture obtained in step (4) is (0.2-3.1):1. The casting process is based on the copper liquid filling the gaps in the powder below the copper foil after the vacuum oscillation is completed.

[0129] The vacuum in step (6) has a pressure of 7 Pa.

[0130] The programmed cooling in step (6) includes: first cooling to 450°C at a rate of 300°C / min, and then cooling naturally to room temperature.

[0131] The resulting finished product has dimensions of 10mm × 10mm × 0.5mm and a film thickness of approximately 500μm.

[0132] Example 5: Preparation of a graphene-copper-based enhanced thermal conductive film:

[0133] (1) Take copper foam powder and pretreat it;

[0134] (2) Graphene was chemically deposited onto the pretreated copper foam powder to obtain graphene composite copper foam powder.

[0135] (3) Mix the graphene composite foamed copper powder obtained in step (2) with the foamed graphene powder, add the graphene / pure copper mixed powder, and ball mill;

[0136] (4) Copper is vapor-deposited into the mixture obtained in step (3);

[0137] (5) After mixing the mixture obtained in step (4), spread it evenly on the bottom of the flat mold, cover the upper surface with copper foil, and cast copper liquid under vibration conditions;

[0138] (6) The graphene copper-based enhanced thermal conductive film was obtained by cooling the film under vacuum oscillation conditions.

[0139] The copper foam powder in step (1) has a porosity of 70-85% and a particle size of 53-63 μm.

[0140] The pretreatment described in step (1) specifically includes: placing the copper foam in deionized water, sonicating for 20 minutes, taking it out and placing it in ethanol, sonicating for 20 minutes, taking it out and placing it in acetone, sonicating for 20 minutes.

[0141] The specific conditions for the chemical deposition of graphene in step (2) include: annealing in a hydrogen atmosphere: the atmosphere is hydrogen, the hydrogen gas flow rate is 20 sccm, the pressure is 100 Pa, the temperature is 750 ℃, and the time is 7 min; chemical deposition: the atmosphere is methane, the methane gas flow rate is 20 sccm, the deposition pressure is 100 Pa, the deposition temperature is 750 ℃, and the deposition time is 15 min.

[0142] The foamed graphene powder in step (3) has a foam pore size of 0.005-0.1 mm, an open porosity of 40-99.9%, and a powder particle size of 53-63 μm.

[0143] The mass ratio of the graphene composite copper foam powder to the graphene foam powder obtained in step (2) is 5.5:1.

[0144] The mass ratio of the graphene composite foam copper powder obtained in step (2) to the graphene / pure copper mixed powder is 5.5:1.

[0145] In step (3), the graphene / pure copper mixed powder has a particle size of 3-20 μm, and the mass ratio of graphene powder to pure copper powder is 2.2:1.

[0146] The ball milling in step (3) is a dry ball milling process, and the milling time is 20 minutes.

[0147] The conditions for copper vapor deposition in step (4) include: a vacuum degree of 5 × 10⁻⁶. -4 Below Pa, the evaporation current is 110A and the evaporation time is 20s.

[0148] The copper foil in step (5) has a thickness of 400 μm.

[0149] The mixture obtained in step (4) in step (5) is spread evenly to a thickness of about 600 μm.

[0150] In step (5), a gap is left between the copper foil and the side wall of the mold, with a gap width of 0.3-0.8 mm.

[0151] The temperature of the copper liquid in step (5) is 1125℃.

[0152] The volume ratio of the copper liquid in step (5) to the mixture obtained in step (4) is (0.2-3.1):1. The casting process is based on the copper liquid filling the gaps in the powder below the copper foil after the vacuum oscillation is completed.

[0153] The vacuum in step (6) has a pressure of 7 Pa.

[0154] The programmed cooling in step (6) includes: first cooling to 450°C at a rate of 300°C / min, and then cooling naturally to room temperature.

[0155] The resulting finished product has dimensions of 10mm × 10mm × 1.0mm and a film thickness of approximately 1000μm.

[0156] Comparative Example 1: Preparation of a graphene-reinforced copper-based composite material:

[0157] 1. Place the foamed copper in acetone and sonicate for 10 min to obtain pretreated foamed copper. Place the pretreated foamed copper in a chemical vapor deposition apparatus, evacuate, and then introduce hydrogen gas. Adjust the hydrogen gas flow rate to 10 sccm and the pressure in the chemical vapor deposition apparatus to 105 Pa. Under the pressure of 105 Pa and hydrogen atmosphere, raise the temperature to 980℃ and anneal at 980℃ for 20 min.

[0158] 2. Methane was introduced and the methane gas flow rate was adjusted to 40 sccm. Deposition was carried out under the conditions of 105 Pa pressure and 980 °C temperature for 20 min. After deposition, the heating power was turned off and the methane supply was stopped. The mixture was cooled to room temperature under a hydrogen atmosphere to obtain three-dimensional graphene / copper foam.

[0159] 3. Place the three-dimensional graphene / foamed copper in a vacuum coating apparatus and evacuate to a vacuum level of 5×10⁻⁶. -4 Below Pa, using copper as the vapor deposition material, the vapor deposition current was adjusted to 100A and the vapor deposition time to 10s, resulting in three-dimensional graphene / copper foam with copper vapor deposition.

[0160] 4. Place the three-dimensional graphene / copper foam with copper vapor deposited on it and copper powder into a graphite mold. Under the conditions of sintering pressure of 40MPa, current on-off time ratio of 32ms:8ms and heating rate of 50℃ / min, raise the temperature to 900℃, and then perform discharge plasma sintering for 3min under the conditions of sintering pressure of 40MPa, current on-off time ratio of 32ms:8ms and sintering temperature of 900℃.

[0161] The mass ratio of the three-dimensional graphene / copper foam coated with copper to copper powder is 1:15.

[0162] The current on-time ratio of 32ms:8ms mentioned in step four is specifically achieved by cycling the current on time for 32ms and the current off time for 8ms within 1 to 5 minutes of heating and discharge plasma sintering.

[0163] 5. Turn off the discharge plasma sintering equipment, use water cooling to cool down, and take out the block composite material to obtain the three-dimensional graphene-reinforced copper-based composite material with a material size of 10mm×10mm×0.1mm.

[0164] Comparative Example 2: Preparation of a graphene-reinforced copper-based composite material:

[0165] 1. Place the foamed copper in acetone and sonicate for 10 min to obtain pretreated foamed copper. Place the pretreated foamed copper in a chemical vapor deposition apparatus, evacuate, and then introduce hydrogen gas. Adjust the hydrogen gas flow rate to 10 sccm and the pressure in the chemical vapor deposition apparatus to 105 Pa. Under the pressure of 105 Pa and hydrogen atmosphere, raise the temperature to 980℃ and anneal at 980℃ for 20 min.

[0166] 2. Methane was introduced and the methane gas flow rate was adjusted to 40 sccm. Deposition was carried out under the conditions of 105 Pa pressure and 980 °C temperature for 20 min. After deposition, the heating power was turned off and the methane supply was stopped. The mixture was cooled to room temperature under a hydrogen atmosphere to obtain three-dimensional graphene / copper foam.

[0167] 3. Place the three-dimensional graphene / foamed copper in a vacuum coating apparatus and evacuate to a vacuum level of 5×10⁻⁶. -4 Below Pa, using copper as the vapor deposition material, the vapor deposition current was adjusted to 100A and the vapor deposition time to 10s, resulting in three-dimensional graphene / copper foam with copper vapor deposition.

[0168] 4. Place the three-dimensional graphene / copper foam with copper vapor deposited on it and copper powder into a graphite mold. Under the conditions of sintering pressure of 40MPa, current on-off time ratio of 32ms:8ms and heating rate of 50℃ / min, raise the temperature to 900℃, and then perform discharge plasma sintering for 3min under the conditions of sintering pressure of 40MPa, current on-off time ratio of 32ms:8ms and sintering temperature of 900℃.

[0169] The mass ratio of the three-dimensional graphene / copper foam coated with copper to copper powder is 1:15.

[0170] The current on-time ratio of 32ms:8ms mentioned in step four is specifically achieved by cycling the current on time for 32ms and the current off time for 8ms within 1 to 5 minutes of heating and discharge plasma sintering.

[0171] 5. Turn off the discharge plasma sintering equipment, use water cooling to cool down, and take out the block composite material to obtain a three-dimensional graphene-reinforced copper-based composite material with a material size of 10mm×10mm×0.5mm.

[0172] Comparative Example 3: Preparation of a graphene-reinforced copper-based composite material:

[0173] 1. Place the foamed copper in acetone and sonicate for 10 min to obtain pretreated foamed copper. Place the pretreated foamed copper in a chemical vapor deposition apparatus, evacuate, and then introduce hydrogen gas. Adjust the hydrogen gas flow rate to 10 sccm and the pressure in the chemical vapor deposition apparatus to 105 Pa. Under the pressure of 105 Pa and hydrogen atmosphere, raise the temperature to 980℃ and anneal at 980℃ for 20 min.

[0174] 2. Methane was introduced and the methane gas flow rate was adjusted to 40 sccm. Deposition was carried out under the conditions of 105 Pa pressure and 980 °C temperature for 20 min. After deposition, the heating power was turned off and the methane supply was stopped. The mixture was cooled to room temperature under a hydrogen atmosphere to obtain three-dimensional graphene / copper foam.

[0175] 3. Place the three-dimensional graphene / foamed copper in a vacuum coating apparatus and evacuate to a vacuum level of 5×10⁻⁶. -4 Below Pa, using copper as the vapor deposition material, the vapor deposition current was adjusted to 100A and the vapor deposition time to 10s, resulting in three-dimensional graphene / copper foam with copper vapor deposition.

[0176] 4. Place the three-dimensional graphene / copper foam with copper vapor deposited on it and copper powder into a graphite mold. Under the conditions of sintering pressure of 40MPa, current on-off time ratio of 32ms:8ms and heating rate of 50℃ / min, raise the temperature to 900℃, and then perform discharge plasma sintering for 3min under the conditions of sintering pressure of 40MPa, current on-off time ratio of 32ms:8ms and sintering temperature of 900℃.

[0177] The mass ratio of the three-dimensional graphene / copper foam coated with copper to copper powder is 1:15.

[0178] The current on-time ratio of 32ms:8ms mentioned in step four is specifically achieved by cycling the current on time for 32ms and the current off time for 8ms within 1 to 5 minutes of heating and discharge plasma sintering.

[0179] 5. Turn off the discharge plasma sintering equipment, use water cooling to cool down, and take out the block composite material to obtain the three-dimensional graphene-reinforced copper-based composite material with a material size of 10mm×10mm×1.0mm.

[0180] Performance testing:

[0181] The products obtained in the above embodiments and comparative examples were tested for hardness, electrical conductivity, and thermal conductivity using the same method. The results are as follows:

[0182] Tensile strength (MPa) <![CDATA[Thermal conductivity W / m -1 ·K -1 > Conductivity S / m Example 1 847 487 <![CDATA[7.1×10 7 ]]> Example 2 859 471 <![CDATA[6.6×10 7 ]]> Example 3 863 469 <![CDATA[8.0×10 7 ]]> Example 4 854 461 <![CDATA[7.5×10 7 ]]> Example 5 838 449 <![CDATA[7.3×10 7 ]]> Comparative Example 1 808 415 <![CDATA[6.3×10 7 ]]> Comparative Example 2 773 390 <![CDATA[5.8×10 7 ]]> Comparative Example 3 732 371 <![CDATA[4.4×10 7 ]]>

[0183] The test results above show that the graphene copper-based reinforced thermal conductive material (film) prepared by the traditional method exhibits a significant decrease in performance as the film thickness increases. However, the graphene copper-based reinforced thermal conductive film prepared by the method provided in this application has high strength and better mechanical properties than the graphene copper-based reinforced thermal conductive film prepared by the traditional method. The film thickness can be controlled within a very large range, and within the controllable film thickness range, the mechanical and electrical properties of the film remain stable. The prepared product can be widely produced and applied.

[0184] The preferred embodiments and examples of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments and examples. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the concept of the present invention.

Claims

1. A method for preparing a graphene copper-based enhanced thermally conductive film, characterized in that: Includes the following steps: (1) Take copper foam powder and pretreat it; (2) Graphene was chemically deposited onto the pretreated copper foam powder to obtain graphene composite copper foam powder. (3) Mix the graphene composite copper foam powder obtained in step (2) with the graphene foam powder, add the graphene / pure copper mixed powder, and ball mill; (4) Copper is vapor-deposited into the mixture obtained in step (3); (5) After mixing the mixture obtained in step (4), spread it evenly on the bottom of the flat mold, cover the upper surface with copper foil, and cast the copper liquid under vibration conditions; (6) Under vacuum oscillation conditions, the temperature was programmed to obtain a graphene copper-based enhanced thermal conductive film; The copper foam powder in step (1) has a porosity of 70-85% and a particle size of 38-74 μm. The pretreatment in step (1) specifically includes: placing the copper foam in deionized water, ultrasonically treating it for 10-30 min, taking it out and placing it in ethanol, ultrasonically treating it for 10-30 min, taking it out and placing it in acetone, ultrasonically treating it for 10-30 min. The specific conditions for the chemical deposition of graphene in step (2) include: annealing in a hydrogen atmosphere: the atmosphere is hydrogen, the hydrogen gas flow rate is 15 sccm-25 sccm; the pressure is 100 Pa; the temperature is 700-850 ℃, and the time is 5-8 min; chemical deposition: the atmosphere is methane, the methane gas flow rate is 10 sccm-30 sccm; the deposition pressure is 100 Pa; the deposition temperature is 700-850 ℃; and the deposition time is 5 min-20 min. The foamed graphene powder in step (3) has a foam pore size of 0.005-0.1 mm, an open porosity of 40-99.9%, and a powder particle size of 38-74 μm. The mass ratio of the graphene composite foamed copper powder obtained in step (2) to the foamed graphene powder in step (3) is (1.7-9.2):1; the mass ratio of the graphene composite foamed copper powder obtained in step (2) to the graphene / pure copper mixed powder in step (3) is (1.7-9.2):(0.3-4.9); In step (3), the graphene / pure copper mixed powder has a particle size of 3-20 μm, and the mass ratio of graphene powder to pure copper powder is (1.1-3.7):1; the ball milling in step (3) is dry ball milling, and the ball milling time is 10-30 min. The conditions for copper vapor deposition in step (4) include: a vacuum degree of 5 × 10⁻⁶. -4 For pressures below Pa, the vapor deposition current is 100A-120A, and the vapor deposition time is 1s-30s. The copper foil in step (5) has a thickness of 20-600 μm; the mixture obtained in step (4) in step (5) has a thickness of 40-1000 μm after being mixed evenly and laid flat; a gap is left between the copper foil in step (5) and the side wall of the mold, and the gap width is 0.3-0.8 mm; The temperature of the copper liquid in step (5) is 1090-1150℃; the volume ratio of the copper liquid in step (5) to the mixture obtained in step (4) is (0.2-3.1):1; the casting process is based on the copper liquid filling the gaps in the powder below the copper foil after the vacuum oscillation is completed. The vacuum in step (6) has a pressure of 4-10 Pa; the programmed cooling in step (6) includes: first cooling to 450°C at a rate of 200-400°C / min, and then cooling naturally to room temperature.