High-thermal-conductivity diamond composite material and preparation method thereof

Abstract

The invention relates to the technical field of diamond composite materials, in particular to a high-thermal-conductivity diamond composite material and a preparation method thereof. The diamond composite material comprises the following components in parts by weight: 50 parts of diamond powder, 5-10 parts of a graphene quantum dot solution, 10-30 parts of Cr / Cu-MOF and 10-20 parts of polyvinyl alcohol. The graphene quantum dots and the Cr / Cu-MOF are introduced as the composite interface modifier, the interface structure and the bonding state of the diamond composite material are synergistically optimized, the heat conductivity of the composite material is effectively improved, and the requirement of a high-power electronic device for a heat dissipation material is fully met.

Description

Technical Field

[0001] This invention relates to the field of diamond composite material technology, specifically to a high thermal conductivity diamond composite material and its preparation method. Background Technology

[0002] With the rapid development of microelectronics integration technology, the continuous shrinking of chip feature sizes and the widespread application of three-dimensional heterogeneous integration architectures have led to a sharp increase in device power density and a significant increase in heat generation per unit volume. This places unprecedented demands on the heat dissipation performance of electronic packaging materials. Research shows that for every 10°C increase in semiconductor device temperature, its lifespan is reduced by approximately 50%, and the thermal stress caused by temperature fluctuations is the main cause of thermal fatigue failure in microcircuits. This makes the development of advanced thermal management materials with both ultra-high thermal conductivity and a controllable coefficient of thermal expansion crucial for continuing Moore's Law. Other traditional materials, such as tungsten copper, molybdenum copper alloys, and aluminum nitride ceramics, also struggle to achieve an ideal balance between ultra-high thermal conductivity, a controllable coefficient of thermal expansion, and good processing performance, failing to meet the stringent requirements of next-generation electronic packaging for heat dissipation efficiency and reliability.

[0003] Diamond, as the substance with the best known thermal conductivity in nature, is an ideal reinforcing phase for high thermal conductivity composite materials. However, diamond alone is difficult to use directly as an encapsulation material. Combining it with a metal with high thermal conductivity, however, promises to synergistically leverage the ultra-high thermal conductivity of diamond and the excellent processing properties of the metal, achieving ultra-high thermal conductivity materials with adjustable coefficients of thermal expansion. However, the practical application of existing diamond composite materials faces a core technological bottleneck: the bonding performance between diamond and the doped metal is poor, and there is no solid-state reaction between the two at high temperatures, making densification and sintering difficult, resulting in high interfacial thermal resistance. Therefore, how to minimize interfacial thermal resistance through innovative material design and preparation processes has become a core issue in promoting the industrial application of this composite material in microelectronics integration technology. Summary of the Invention

[0004] In view of the above situation and to overcome the shortcomings of the prior art, the present invention provides a diamond composite material with high thermal conductivity and a method for preparing the same.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This invention proposes a diamond composite material with high thermal conductivity, which comprises the following components by weight: 50 parts diamond powder, 5-10 parts graphene quantum dot solution, 10-30 parts Cr / Cu-MOF, and 10-20 parts polyvinyl alcohol.

[0006] Preferably, the method for preparing the graphene quantum dot solution includes the following steps: A1. Citric acid and urea are used as precursors and dispersed in water to form a solution mixture; A2. Transfer the solution mixture to a reaction vessel with a polytetrafluoroethylene liner, heat at 170~200℃ for 5~8 h, cool to room temperature, centrifuge at 4000~6000 rpm to remove large particles, and use a dialysis membrane of 2000~10000 Da to remove unreacted small molecules to obtain a graphene quantum dot solution.

[0007] Preferably, in step A1, the ratio of citric acid, urea, and water is 1 mol: 1~2 mol: 10 L.

[0008] Preferably, the preparation method of the Cr / Cu-MOF includes the following steps: B1. Chromium chloride and copper chloride are used as mixed metal precursors, and added to DMF along with terephthalic acid and acetic acid. The mixture is stirred and dissolved evenly to form the precursor. B2. The precursor prepared in step A1 is transferred to a reaction vessel with a polytetrafluoroethylene liner and heated at 100-140°C for 22-26 h. After cooling to room temperature, the precipitate is collected by centrifugation. The precipitate is washed three times with alternating ethanol and deionized water and then dried in a vacuum drying oven at 40-80°C for 12-24 h to obtain Cr / Cu-MOF.

[0009] Preferably, in step B1, the molar ratio of chromium chloride to copper chloride is 1:1~2, the total molar ratio of terephthalic acid to the mixed metal precursor is 1:1, the molar ratio of acetic acid to terephthalic acid is 10:1, and the volume ratio of DMF to terephthalic acid is 20 mL:1 mmol.

[0010] This invention also proposes a method for preparing a diamond composite material with high thermal conductivity, specifically including the following steps: S1. Weigh diamond powder, graphene quantum dot solution, and Cr / Cu-MOF according to their weight parts, then ultrasonically stir and mix them evenly. Add polyvinyl alcohol and water to prepare a polyvinyl alcohol aqueous solution with a mass fraction of 8~12%, granulate, and then press into shape. S2. Under a nitrogen atmosphere, the blank formed by pressing in S1 is heated to 550~700℃ to remove the glue for 1~2 hours, then heated to 1100~1500℃ for sintering for 3~5 hours, and then cooled to room temperature at a cooling rate of 2~4℃ / min to obtain diamond composite material.

[0011] The beneficial effects achieved by this invention are as follows: This invention synergistically optimizes the interfacial structure and bonding state of diamond composite materials by introducing graphene quantum dots and Cr / Cu-MOF as composite interface modifiers. Graphene quantum dots, with their ultra-high specific surface area and abundant surface functional groups, can effectively coat diamond particles, fill microscopic pores, and improve powder dispersibility. Further carbonization of graphene quantum dots at high temperatures generates active carbon species that help form a thin carbon transition zone at the diamond interface, thereby enhancing interfacial bonding. During high-temperature sintering, Cr / Cu-MOF transforms into Cr / Cu-MOF derivatives, reducing thermal damage to the diamond powder and uniformly dispersing it at the diamond interface, acting as an interface modifier and providing a continuous pathway for heat transfer, achieving efficient heat transport. Simultaneously, during sintering in an inert gas atmosphere, graphene quantum dots and Cr / Cu-MOF derivatives transform into chemical bonds, significantly enhancing interfacial bonding and synergistically improving the thermal conductivity of the composite material. The polyvinyl alcohol-assisted granulation and stepped temperature-controlled sintering process employed significantly improves process controllability and molding quality while ensuring high material density. The high thermal conductivity diamond composite material proposed in this invention fully meets the requirements of high-power electronic devices for high thermal conductivity, low expansion, and high reliability in heat dissipation materials. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a transmission electron microscope image of the graphene quantum dots prepared in Example 1; Figure 2 This is a scanning electron microscope image of the Cr / Cu-MOF prepared in Example 1. Detailed Implementation

[0014] The present invention will be further described in detail below through embodiments and comparative examples, but it should not be construed as the scope of the present invention being limited to the following embodiments. All technologies implemented based on the above content of the present invention fall within the scope of the present invention.

[0015] Unless otherwise specified, the experimental methods used in the following examples are conventional methods; unless otherwise specified, the experimental materials used in the following examples and comparative examples were all purchased from commercial channels.

[0016] Example 1: This embodiment proposes a diamond composite material with high thermal conductivity, which comprises the following raw materials in parts by weight: 50 parts diamond powder, 10 parts graphene quantum dot solution, 20 parts Cr / Cu-MOF, and 20 parts polyvinyl alcohol.

[0017] The preparation method of the graphene quantum dot solution in this embodiment includes the following steps: A1. Using 1 mmol citric acid and 1 mmol urea as precursors, disperse them in 10 mL of water to form a solution mixture; A2. The solution mixture was transferred to a reaction vessel with a polytetrafluoroethylene liner, heated at 200°C for 5 h, cooled to room temperature, centrifuged at 6000 rpm to remove large particles, and unreacted small molecules were removed using a 10000 Da dialysis membrane to obtain a graphene quantum dot solution.

[0018] The preparation method of Cr / Cu-MOF in this embodiment includes the following steps: B1. Take 1 mmol of chromium chloride and 1 mmol of copper chloride as a mixed metal precursor, add them to 40 mL of DMF along with 2 mmol of terephthalic acid and 20 mmol of acetic acid, stir and dissolve evenly to form the precursor. B2. The precursor prepared in step B1 was transferred to a reaction vessel with a polytetrafluoroethylene liner, heated at 120°C for 24 h, cooled to room temperature, centrifuged to collect the precipitate, washed three times alternately with ethanol and deionized water, and dried in a vacuum drying oven at 40°C for 24 h to obtain Cr / Cu-MOF.

[0019] This embodiment also proposes a method for preparing a diamond composite material with high thermal conductivity, which specifically includes the following steps: S1. Weigh diamond powder, graphene quantum dot solution, and Cr / Cu-MOF according to their weight parts, then ultrasonically stir and mix them evenly. Add a 10% polyvinyl alcohol aqueous solution prepared with polyvinyl alcohol and water, granulate, and then press into shape. S2. Under a nitrogen atmosphere, the blank formed by pressing in S1 is heated to 600℃ for 2 hours to remove the glue, then heated to 1500℃ for 3 hours to sinter, and then cooled to room temperature at a cooling rate of 4℃ / min to obtain the diamond composite material.

[0020] Example 2: This embodiment proposes a diamond composite material with high thermal conductivity, which comprises the following raw materials in parts by weight: 50 parts diamond powder, 7 parts graphene quantum dot solution, 30 parts Cr / Cu-MOF, and 15 parts polyvinyl alcohol.

[0021] The preparation method of the graphene quantum dot solution in this embodiment includes the following steps: A1. Using 1 mmol citric acid and 2 mmol urea as precursors, disperse them in 10 mL of water to form a solution mixture; A2. The solution mixture was transferred to a reaction vessel with a polytetrafluoroethylene liner, heated at 170°C for 6 h, cooled to room temperature, centrifuged at 4000 rpm to remove large particles, and unreacted small molecules were removed using a 2000 Da dialysis membrane to obtain a graphene quantum dot solution.

[0022] The preparation method of Cr / Cu-MOF in this embodiment includes the following steps: B1. Take 1 mmol of chromium chloride and 2 mmol of copper chloride as a mixed metal precursor, add them to 60 mL of DMF along with 3 mmol of terephthalic acid and 30 mmol of acetic acid, stir and dissolve evenly to form the precursor; B2. The precursor prepared in step B1 was transferred to a reaction vessel with a polytetrafluoroethylene liner, heated at 100°C for 26 h, cooled to room temperature, centrifuged to collect the precipitate, washed three times with alternating ethanol and deionized water, and dried in a vacuum drying oven at 60°C for 12 h to obtain Cr / Cu-MOF.

[0023] This embodiment also proposes a method for preparing a diamond composite material with high thermal conductivity, which specifically includes the following steps: S1. Weigh diamond powder, graphene quantum dot solution, and Cr / Cu-MOF according to their weight parts, then ultrasonically stir and mix them evenly. Add polyvinyl alcohol and water to prepare an 8% polyvinyl alcohol aqueous solution, granulate, and then press into shape. S2. Under a nitrogen atmosphere, the blank formed by pressing in S1 is heated to 700℃ for 1 hour to remove the glue, then heated to 1100℃ for sintering for 5 hours, and then cooled to room temperature at a cooling rate of 3℃ / min to obtain the diamond composite material.

[0024] Example 3: This embodiment proposes a diamond composite material with high thermal conductivity, which comprises the following raw materials in parts by weight: 50 parts diamond powder, 5 parts graphene quantum dot solution, 10 parts Cr / Cu-MOF, and 10 parts polyvinyl alcohol.

[0025] The preparation method of the graphene quantum dot solution in this embodiment includes the following steps: A1. Using 1 mmol citric acid and 1.5 mmol urea as precursors, disperse them in 10 mL of water to form a solution mixture; A2. The solution mixture was transferred to a reaction vessel with a polytetrafluoroethylene liner, heated at 180°C for 8 h, cooled to room temperature, centrifuged at 5000 rpm to remove large particles, and unreacted small molecules were removed using a 60000 Da dialysis membrane to obtain a graphene quantum dot solution.

[0026] The preparation method of Cr / Cu-MOF in this embodiment includes the following steps: B1. Take 1 mmol of chromium chloride and 1.5 mmol of copper chloride as a mixed metal precursor, add them to 50 mL of DMF along with 2.5 mmol of terephthalic acid and 25 mmol of acetic acid, stir and dissolve evenly to form the precursor; B2. The precursor prepared in step B1 was transferred to a reaction vessel with a polytetrafluoroethylene liner, heated at 140°C for 22 h, cooled to room temperature, centrifuged to collect the precipitate, washed three times with alternating ethanol and deionized water, and dried in a vacuum drying oven at 80°C for 16 h to obtain Cr / Cu-MOF.

[0027] This embodiment also proposes a method for preparing a diamond composite material with high thermal conductivity, which specifically includes the following steps: S1. Weigh diamond powder, graphene quantum dot solution, and Cr / Cu-MOF according to their weight parts, then ultrasonically stir and mix them evenly. Add a 12% polyvinyl alcohol aqueous solution prepared with polyvinyl alcohol and water, granulate, and then press into shape. S2. Under a nitrogen atmosphere, the blank formed by pressing in S1 is heated to 600℃ for 1.5 h to remove the glue, then heated to 1400℃ for 4 h to sinter, and then cooled to room temperature at a cooling rate of 3℃ / min to obtain the diamond composite material.

[0028] Comparative Example 1: This comparative example presents a diamond composite material with high thermal conductivity. The only difference between this example and Example 1 is that no graphene quantum dot solution is added. All other components, component contents, and experimental steps are the same as in Example 1.

[0029] Comparative Example 2: This comparative example presents a diamond composite material with high thermal conductivity. The only difference between this example and Example 1 is that Cr / Cu-MOF is not added. All other components, component contents, and experimental procedures are the same as in Example 1.

[0030] Comparative Example 3: This comparative example presents a diamond composite material with high thermal conductivity, which differs from Example 1 only in that Cr / Cu-MOF is replaced with Cu-MOF; the remaining components, component contents, and experimental procedures are the same as in Example 1.

[0031] The preparation method of Cu-MOF includes the following steps: B1. Take 2 mmol of copper chloride as a metal precursor, add it to 40 mL of DMF along with 2 mmol of terephthalic acid and 20 mmol of acetic acid, and stir until dissolved to form a precursor. B2. The precursor prepared in step B1 is transferred to a reaction vessel with a polytetrafluoroethylene liner, heated at 120°C for 24 h, cooled to room temperature, centrifuged to collect the precipitate, washed three times with alternating ethanol and deionized water, and dried in a vacuum drying oven at 40°C for 24 h to obtain Cu-MOF.

[0032] Comparative Example 4: This comparative example presents a diamond composite material with high thermal conductivity, which differs from Example 1 only in that Cr / Cu-MOF is replaced with Cr-MOF; the other components, component contents, and experimental procedures are the same as in Example 1.

[0033] The preparation method of Cr-MOF includes the following steps: B1. Take 2 mmol of chromium chloride as a metal precursor, add it, along with 2 mmol of terephthalic acid and 20 mmol of acetic acid, into 40 mL of LDM, stir and dissolve evenly to form a precursor. B2. The precursor prepared in step B1 is transferred to a reaction vessel with a polytetrafluoroethylene liner, heated at 120°C for 24 h, cooled to room temperature, centrifuged to collect the precipitate, washed three times alternately with ethanol and deionized water, and dried in a vacuum drying oven at 40°C for 24 h to obtain Cr-MOF.

[0034] Experimental Example 1: The graphene quantum dot solution prepared in Example 1 was observed using transmission electron microscopy, and the microstructure of Cr / Cu-MOF was analyzed using scanning electron microscopy.

[0035] Figure 1 The image shows a transmission electron microscope (TEM) image of the graphene quantum dots prepared in Example 1. As shown in the figure, the graphene quantum dots in the solution have a uniform particle size of about 2 nm and obvious graphene lattice fringes, indicating the successful preparation of the graphene quantum dot solution. Figure 2 The image shows a scanning electron microscope (SEM) image of the Cr / Cu-MOF prepared in Example 1. As shown in the figure, the Cr / Cu-MOF has a polygonal structure, and the non-uniform morphology is due to the bimetallic mixed MOFs, indicating the successful preparation of the Cr / Cu-MOF.

[0036] Experiment Example 2: Performance Testing The density of the samples was tested using the Archimede water displacement method; Bending strength was tested using the three-point bending method on an Xww universal testing machine. Hardness was tested using an MC010 hardness tester. First, the sample surface was polished with a polishing machine to remove surface defects. Then, a flat and smooth area was selected for testing. The average value of the five sampling points was taken as the final hardness value. The fracture toughness of the sample was tested using the indentation method. Thermal conductivity was tested using a laser thermal conductivity meter (DFX-500) (25℃); The coefficient of thermal expansion was tested using a PCY series high-temperature thermal expansion meter (thermal expansion coefficient meter) (25~700℃).

[0037] As shown in the table above, the performance of the diamond composite material with graphene quantum dot solution and Cr / Cu-MOF is significantly improved. Example 1 exhibits extremely high overall performance, with a thermal conductivity as high as 655 W / (m·K) and a coefficient of thermal expansion as low as [missing value]. It exhibits excellent thermal compatibility with semiconductor chips. In contrast, the absence of any key component (such as the absence of graphene quantum dot solution in Comparative Example 1 or Cr / Cu-MOF in Comparative Example 2) leads to deterioration of interfacial bonding, resulting in decreased density and thermal conductivity. Meanwhile, Comparative Examples 3-4 show that Cr / Cu has a synergistic promoting effect on the interfacial layer performance of the composite material, confirming the core role of this synergistic interfacial modification design in achieving ultra-high thermal conductivity, high strength and toughness, and low thermal expansion of the material. This fully demonstrates the enormous potential of this composite material as a new generation of high-performance electronic packaging heat dissipation material.

[0038] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention. The actual application is not limited to this. In conclusion, if those skilled in the art are inspired by this description and design similar methods and embodiments without departing from the spirit of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A diamond composite material with high thermal conductivity, characterized in that, The diamond composite material comprises the following raw materials in parts by weight: 50 parts diamond powder, 5-10 parts graphene quantum dot solution, 10-30 parts Cr / Cu-MOF, and 10-20 parts polyvinyl alcohol.

2. The high thermal conductivity diamond composite material according to claim 1, characterized in that, The method for preparing the graphene quantum dots includes the following steps: A1. Citric acid and urea are used as precursors and dispersed in water to form a solution mixture; A2. Transfer the solution mixture to a reaction vessel with a polytetrafluoroethylene liner, heat at 170~200℃ for 5~8 h, cool to room temperature, centrifuge at 4000~6000 rpm to remove large particles, and use a dialysis membrane of 2000~10000 Da to remove unreacted small molecules to obtain a graphene quantum dot solution.

3. The high thermal conductivity diamond composite material according to claim 2, characterized in that, In step A1, the ratio of citric acid, urea, and water is 1 mol: 1~2 mol: 10 L.

4. The high thermal conductivity diamond composite material according to claim 1, characterized in that, The preparation method of the Cr / Cu-MOF, Includes the following steps B1. Chromium chloride and copper chloride are used as mixed metal precursors, and added to DMF along with terephthalic acid and acetic acid. The mixture is stirred and dissolved evenly to form the precursor. B2. The precursor prepared in step B1 is transferred to a reaction vessel with a polytetrafluoroethylene liner and heated at 100-140°C for 22-26 h. After cooling to room temperature, the precipitate is collected by centrifugation. The precipitate is washed alternately with ethanol and deionized water and then dried in a vacuum drying oven at 40-80°C for 12-24 h to obtain Cr / Cu-MOF.

5. The high thermal conductivity diamond composite material according to claim 4, characterized in that, In step B1, the molar ratio of chromium chloride to copper chloride is 1:1~2, the total molar ratio of terephthalic acid to mixed metal precursor is 1:1, the molar ratio of acetic acid to terephthalic acid is 10:1, and the volume ratio of DMF to terephthalic acid is 20 mL:1 mmol.

6. A method for preparing a high thermal conductivity diamond composite material as described in any one of claims 1 to 5, characterized in that, Specifically, the following steps are included: S1. Weigh diamond powder, graphene quantum dot solution, and Cr / Cu-MOF according to their weight parts, then ultrasonically stir and mix them evenly. Add polyvinyl alcohol and water to prepare a polyvinyl alcohol aqueous solution with a mass fraction of 8~12%, granulate, and then press into shape. S2. Under a nitrogen atmosphere, the blank formed by pressing in S1 is heated to 550~700℃ for 1~2 hours to remove the glue, then heated to 1100~1500℃ for sintering for 3~5 hours, and then cooled to room temperature at a cooling rate of 2~4℃ / min to obtain diamond composite material.

Images