FOAM SKELETON REINFORCED COMPOSITE, PREPARATION METHOD THEREFOR, AND APPLICATION THEREOF

Abstract

A foamed skeleton reinforced composite, comprising a foamed skeleton and a matrix material. The foamed skeleton is selected from at least one of a metal foamed skeleton, an inorganic non-metal foamed skeleton, and an organic foamed skeleton. The matrix material is selected from a metal or a polymer.

Claims

1-15. (canceled)

16. A composite material reinforced by a foamed skeleton, comprising: a foamed skeleton having pores, wherein a material of the foamed skeleton is a metal material, an inorganic non-metallic material comprising a ceramic material and carbon, or an organic non-metallic material; and a matrix, wherein a material of the matrix is a metal material or a polymer material.

17. The composite material of claim 16, wherein the metal material of the matrix is selected from a group consisting of Al, Cu, Mg, Ag, Ti, Co, Ni, W, Mo, Ta, Nb, and any alloys thereof; and wherein the polymer material of the matrix is a paraffin, a thermoplastic polymer or a thermosetting polymer; the thermoplastic polymer is polyethylene, polypropylene, polystyrene, polyvinyl chloride, polytetrafluoroethylene, nylon, polycarbonate, polymethyl methacrylate, ethylene glycol, polyterephthalic acid, polyformaldehyde, polyamide, or polysulfone; the thermosetting polymer is an epoxy resin, a phenolic resin, a urea-formaldehyde resin, an amino resin, a melamine resin, an unsaturated polyester resin, a silicone rubber, a foamed polystyrene, or a polyurethane.

18. The composite material of claim 16, wherein the metal material of the foamed skeleton is Ni, Cu, Ti, Co, W, Mo, Cr, Fe Ni or Al; wherein the inorganic non-metallic material of the foamed skeleton is carbon, Al.sub.2O.sub.3, ZrO.sub.2, SiC, Si.sub.3N.sub.4, BN, B.sub.4C, AlN, WC or Cr.sub.7C.sub.3; and wherein the organic non-metallic material of the foamed skeleton is sponge, polyurethane (PUR), polystyrene (PS), polyvinyl chloride (PVC), polyethylene (PE) or phenolic resin (PF).

19. The composite material of claim 16, further comprising a reinforcing layer on the foamed skeleton, wherein the reinforcing layer is a diamond film, a graphene film, a carbon nanotube film, a diamond/graphene film, a diamond/carbon nanotube film, a graphene/carbon nanotubes film, a carbon nanotube/graphene film, a carbon nanotube/graphene film, a diamond/graphene/carbon nanotube film, or a diamond/carbon nanotube/graphene film.

20. The composite material of claim 19, wherein the diamond/graphene film is formed by growing graphene on a diamond film in a direction perpendicular to the diamond film to form graphene walls, or in a direction parallel to the diamond film to form a graphene film; the diamond/carbon nanotube film is formed by catalytically growing carbon nanotubes on a diamond film, a nitrogen-doped diamond film, or a boron-doped diamond film in a direction perpendicular to the diamond film, the nitrogen-doped diamond film, or the boron-doped diamond film to form a carbon nanotube forest; the graphene/carbon nanotube film is formed by catalytically growing carbon nanotubes on a graphene film, and the carbon nanotubes ae perpendicular to the graphene film to form a carbon nanotube forest; the carbon nanotube/graphene film is formed by catalytic growing graphene on the surface of carbon nanotube, and the graphene is perpendicular or parallel to the surface of the carbon nanotubes; the diamond/graphene/carbon nanotube film is formed by growing graphene on a diamond film and then catalytically growing carbon nanotubes on the graphene film, the graphene is parallel to the diamond film to form a graphene film, and the carbon nanotubes are perpendicular to the diamond film to form a carbon nanotube forest; the diamond/carbon nanotubes/graphene film is formed by catalytically growing carbon nanotubes on the diamond film, and then growing graphene walls on the surface of carbon nanotubes.

21. The composite material of claim 19, further comprising an intermediate transition layer between the foamed skeleton and the reinforcing layer, wherein a material of the intermediate transition layer is Nb, Ti, Ni, W, Mo, Cr, Ta, Pt, Ag, Si, or any combinations thereof.

22. The composite material of claim 19, further comprising a modifying layer on the reinforcing layer when a material of the matrix is the metal material, wherein a material of the modifying layer is a metal selected from W, Mo, Cr, Ti, Ni, Cu, Al and Pt, a metal carbide selected from tungsten carbide, molybdenum carbide, chromium carbide and titanium carbide, or an alloy selected from a tungsten alloy, a molybdenum alloy, a chromium alloy, a titanium alloy, a nickel alloy, a copper alloy, an aluminum alloy and a platinum alloy.

23. The composite material of claim 16, wherein the pores of the foamed skeleton have a diameter of 0.01-10 mm, a porosity of the foamed skeleton is 40-99%, and the foamed skeleton is a planar structure or a three dimensional structure.

24. The composite material of claim 16, further comprising reinforcing particles distributed in the pores of the foamed skeleton, wherein the reinforcing particles are highly thermal conductivity particles, super-hard and wear-resistant particles, conductive particles, or any combinations thereof, and wherein the highly thermal conductivity particles are selected from at least one of diamond powders, graphene, carbon nanotubes, graphene coated diamond microspheres, carbon nanotube coated diamond microspheres, and carbon nanotube coated graphene, the super-hard and wear-resistant particles are selected from at least one of the diamond powders, SiC, TiC, TiN, AlN, Si.sub.3N.sub.4, Al.sub.2O.sub.3, BN, WC, MoC and Cr.sub.7C.sub.3, and the conductive particles are selected from at least one of graphite, carbon nanotubes, and graphene.

25. The composite material of claim 24, wherein the volume fraction of the matrix is 10-90%, the volume fraction of the foamed skeleton is 5-80%, and the volume fraction of the reinforcing particles is 0-30%.

26. The composite material of claim 25, wherein the foamed skeleton has a three-dimensional bulk structure to reinforce the matrix in a single-body way, or a sheet like or strip-like structure arranged in parallel to reinforce the matrix in a multi-body way.

27. A method of preparing a composite material reinforced by a foamed skeleton, the method comprising: cleaning a foamed skeleton; depositing an intermediate transition layer on the foamed skeleton by electroplating, electroless plating, evaporation, magnetron sputtering, chemical vapor deposition (CVD), or physical vapor deposition (PVD), wherein the intermediate transition layer is a layer of Nb, Ni, Cu, W, Mo, Ti, Ag, Cr, or any combinations thereof; depositing a reinforcing layer on the intermediate transition layer, wherein the reinforcing layer is a diamond film, a graphene film, a carbon nanotube film, a diamond/graphene film, a diamond/carbon nanotubes film, a graphene/carbon nanotubes film, a carbon nanotube/graphene film, a carbon nanotube/graphene film, a diamond/graphene/carbon nanotube film or a diamond/carbon nanotube/graphene film; and compounding the foamed skeleton with a matrix.

28. The method of claim 27, wherein when the reinforcing layer is the diamond film, the graphene film, or the carbon nanotube film, the deposition method of the reinforcing layer comprises: growing a diamond seed layer on the intermediate transition layer, the growing method comprises: immersing the foamed skeleton covered by the intermediate transition layer in a suspension solution of nanocrystalline and/or microcrystalline diamond particles; and planting the nanocrystalline and/or microcrystalline diamond particles onto the foamed skeleton by ultrasonic oscillation, spray atomization, or electrostatic adsorption; and depositing the diamond film, the graphene film, or the carbon nanotube film on the surface of the intermediate transition layer or the diamond particles by CVD.

29. The method of claim 27, wherein when the reinforcing layer is the diamond/graphene film, the diamond/carbon nanotubes film, the graphene/carbon nanotubes film, the carbon nanotube/graphene film, the carbon nanotube/graphene film, the diamond/graphene/carbon nanotube film or the diamond/carbon nanotube/graphene film, the reinforcing layer is deposited by plasma enhanced CVD to increase the deposition rate and control the growing direction, and wherein the diamond/graphene film is formed by growing graphene on a diamond film in a direction perpendicular to the diamond film to form graphene walls, or in a direction parallel to the diamond film to form a graphene film; the diamond/carbon nanotube film is formed by catalytically growing carbon nanotubes on a diamond film, a nitrogen-doped diamond film, or a boron-doped diamond film in a direction perpendicular to the diamond film, the nitrogen-doped diamond film, or the boron-doped diamond film to form a carbon nanotube forest; the graphene/carbon nanotube film is formed by catalytically growing carbon nanotubes on a graphene film, and the carbon nanotubes ae perpendicular to the graphene film to form a carbon nanotube forest; the carbon nanotube/graphene film is formed by catalytic growing graphene on the surface of carbon nanotube, and the graphene is perpendicular or parallel to the surface of the carbon nanotubes; the diamond/graphene/carbon nanotube film is formed by growing graphene on a diamond film and then catalytically growing carbon nanotubes on the graphene film, the graphene is parallel to the diamond film to form a graphene film, and the carbon nanotubes are perpendicular to the diamond film to form a carbon nanotube forest; the diamond/carbon nanotubes/graphene film is formed by catalytically growing carbon nanotubes on the diamond film, and then growing graphene walls on the surface of carbon nanotubes.

30. The method of claim 27, wherein when the material of the matrix is a metal material, the compounding step comprises: depositing a modifying layer on the reinforcing layer by plating, evaporation, magnetron sputtering, chemical vapor deposition or physical vapor deposition, wherein the modifying layer is a metal selected from W, Mo, Cr, Ti, Ni, Ci, Al and Pt, a metal carbide selected from tungsten carbide, molybdenum carbide, chromium carbide and titanium carbide, or an alloy selected from a tungsten alloy, a molybdenum alloy, a chromium alloy, a titanium alloy, a nickel alloy, a copper alloy, an aluminum alloy and a platinum alloy; and compounding the foamed skeleton with reinforcing particles and the matrix by pressure infiltration, pressure-free infiltration, or vacuum suction casting.

31. The method of claim 27, wherein when a material of the matrix is a polymer, the compounding step comprises: mixing the foamed skeleton, the polymer, reinforcing particles, a coupling agent, an antioxidant and processing aids to form a mixture; heating the mixture to a temperature above a melting point of the polymer and below a decomposition temperature of the polymer; compounding the foamed skeleton and the matrix by impregnation curing, injection molding, pressing, injection molding, rolling molding, extrusion forming, laminating forming, or casting forming; and lowering the temperature of the mixture below the melting point of the polymer.

32. The method of claim 27, wherein when a material of the matrix is a paraffin, the compounding step comprises: melting the paraffin; mixing a flame retardant and the melted paraffin to form a solution; dipping the foamed skeleton into the solution to form a mixture; degassing the mixture at a pressure below 10 Pa until no obvious bubbles coming out; and cooling the mixture under an atmosphere of air, N.sub.2, or Ar.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0090] FIG. 1 is a schematic view showing the structure of a foamed skeleton reinforced matrix as a single-body reinforcement in this invention.

[0091] FIG. 2 is a schematic view showing the structure of a foamed skeleton reinforced matrix as a sheet-like reinforcement in parallel arrangement in this invention.

[0092] FIG. 3 is a schematic view showing the structure of a foamed skeleton reinforced matrix as a columnar-like reinforcement in parallel arrangement in this invention.

[0093] FIG. 4 is a top view of FIG. 3.

[0094] FIG. 5 shows that with gas as a heat dissipating fluid, a three-dimensional network porous electronic packaging material is directly compounded with a fan.

[0095] FIG. 6 shows that with liquid as a heat dissipating fluid, a three-dimensional network porous electronic packaging material is directly compounded with a circulation pump.

[0096] FIG. 7 shows SEM images of surface morphologies of a diamond foam prepared in Example 1, wherein FIG. 7(b) is an enlarged view of FIG. 7(a).

[0097] FIG. 8 shows SEM images of surface morphologies of a graphene-coated diamond foam prepared in Example 3, wherein FIG. 8(b) is an enlarged view of FIG. 8(a).

[0098] FIG. 9 shows SEM images of surface morphologies of a carbon nanotube-coated diamond foam prepared in Example 4, wherein FIG. 9(b) is an enlarged view of FIG. 9(a).

DESCRIPTION OF EMBODIMENTS

[0099] The technical proposal of this invention is further described through specific embodiments.

[0100] The technical aspects of the invention is further described through specific embodiments.

[0101] The metal matrix composite material embodiments of this invention are carried out according to the following process or steps:

[0102] (1) A foamed skeleton substrate is ultrasonically rinsed in ethanol, then taken out and dried for use.

[0103] (2) An intermediate transition layer is prepared on the surface of the foamed skeleton substrate by one method selected from electroplating, electroless plating, evaporation, magnetron sputtering, chemical vapor deposition and physical vapor deposition. The intermediate transition layer comprises one of nickel, copper, tungsten, molybdenum, titanium, silver and chromium or a composite metal layer thereof.

[0104] (3) Nanocrystalline and microcrystalline diamond mixed particles, the foamed skeleton substrate, and a solvent are mixed together, heated to boiling, and then under high-power ultrasonic oscillation for 30 min to be uniformly dispersed. Then the foamed skeleton substrate is taken out for drying to obtain a foamed skeleton substrate with a large number of nanocrystalline and microcrystalline diamond particles embedded in the pores thereof.

[0105] (4) A continuous dense reinforcing layer is deposited on the metal substrate surface by hot filament chemical vapor deposition (HFCVD). The reinforcing layer is selected from a diamond film, a graphene film, a carbon nanotube film, graphene-coated diamond, carbon nanotube-coated diamond, carbon nanotube-coated graphene, carbon nanotube/graphene composite film-coated diamond.

[0106] (5) Before a foamed skeleton with the graphene-reinforcing layer is compounded with a matrix material, in order to improve the bonding performance between the reinforcing layer and the matrix material, surface modification of the reinforcing layer is needed. One or more modifying layers are deposited on the surface of the foamed skeleton with the graphene-reinforcing layer by a method selected from electroplating, electroless plating, evaporation, magnetron sputtering, chemical vapor deposition and physical vapor deposition. The modifying layer is selected from at least one of tungsten, tungsten carbide, molybdenum, molybdenum carbide, chromium, chromium carbide, titanium, titanium carbide, nickel, copper, aluminum, platinum, a tungsten alloy, a molybdenum alloy, a chromium alloy, a titanium alloy, a nickel alloy, a copper alloy, an aluminum alloy and a platinum alloy.

[0107] (6) The arrangement of the foamed skeleton reinforcement after surface modification treatment in the matrix can be divided into the following three ways:

[0108] a. The formed skeleton is compounded with the matrix as an integral reinforcement, and the composite material forms an interpenetrating structure of diamond/metal matrix network as a whole. b. The foamed skeletonis compounded with the matrix as a sheet-like reinforcement, and the arrangement direction of the reinforcement in the matrix is parallel arrangement.

[0109] c. The foamed skeleton is compounded with the matrix as a strip-like reinforcement, and the arrangement direction of the reinforcement in the matrix is parallel arrangement.

[0110] (7) The foamed skeleton with the reinforcing layer is compounded with a metal matrix by pressure infiltration technique.

Example 1: Silver-Matrix Composite Reinforced with Foamed Diamond Skeleton

[0111] In this example of silver-matrix composite reinforced with a foamed diamond skeleton in this example, a copper foam was used as a substrate having a pore size of 0.2 mm. The volume fraction of the foamed diamond reinforcement in the composite was 20%. Firstly, according to step (1), the three-dimensional network substrate of the copper foam was cleaned. Then, according to step (2), a molybdenum film, as an intermediate transition layer with a thickness of 50 nm, was deposited on the surface of three-dimensional network skeleton of the copper foam by magnetron sputtering technique. Afterwards, according to step (3), the substrate of the foamed skeleton with a large number of nano-crystalline and micro-crystalline diamond particles in pores was obtained. According to step (4), a diamond film was deposited by hot filament CVD, and the deposition parameters were as follows: the filament-to-substrate distance was 6 mm; the substrate temperature was 800 C.; the filament temperature was 2200 C.; the deposition pressure was 3 kPa; the volume flow ratio of CH.sub.4/H.sub.2 was 1:99. The thickness of the diamond film was 60 m by controlling the deposition time. A three-dimensional network skeleton of the diamond-coated copper foam substrate was obtained. After that, according to step (5), before compounding with a matrix material, a tungsten film was in-situ evaporated on the surface of the foamed diamond skeleton by vacuum evaporation method for surface modification; wherein the thickness of the tungsten film was 200 nm. (6) The foamed diamond skeleton coated with tungsten film was placed in a mold, serving as a sheet-like reinforcement to be compounded with the matrix in parallel arrangement. (7) The foamed diamond skeleton was covered with a silver alloy having a volume that was twice the volume of the foamed diamond skeleton. Then, the mold was placed in a heating furnace, at a temperature of about 950 C. for 30 min under a high-purity nitrogen atmosphere. A silver-matrix composite reinforced by the foamed diamond skeleton was obtained, and the thermal conductivity of the composite was 862 W/(m.Math.K).

Example 2: Copper-Matrix Composite Reinforced with Foamed Graphene Skeleton

[0112] In this example of copper-matrix composite reinforced with a foamed graphene skeleton, porous ceramic Al.sub.2O.sub.3 was used as the substrate having a pore diameter of 2 mm. The volume fraction of the graphene foam reinforcement in composite was 10%. Firstly, the three-dimensional network substrate of Al.sub.2O.sub.3 foam was cleaned according to step (1). Then, according to step (2), a tungsten film, as an intermediate transition layer and with a thickness of 200 nm, was deposited on the surface of the foamed Al.sub.2O.sub.3 skeleton by magnetron sputtering technique. Afterwards, according to step (4), graphene was in-situ grown on the substrate surface by plasma enhanced chemical vapor deposition. During the deposition process, plasma was applied to the substrate of the foamed skeleton to assist the graphene growth. The plasma was confined to the near surface of the foamed skeleton by adding a magnetic field at the bottom of the substrate to increase the plasma bombardment to the surface of foamed skeleton and making the graphene growth perpendicular to the surface of substrate. A foamed skeleton with a large amount of thermally conductive graphene-coated diamond particles in pores and a large amount of graphene walls grown on the surface of skeleton was obtained. Deposition parameters were as follows: the substrate temperature was 850 C.; the deposition pressure was 5.0 kPa; the volume flow ratio of CH.sub.4/H.sub.2 was 10:90; the plasma current density was 5 mA/cm.sup.2; the magnetic field intensity was 500 Gs. Meanwhile, the orientation of the graphene growth was controlled under the applied electric field to make graphene form graphene walls perpendicular to the surface of substrate. A three-dimensional network skeleton of graphene-coated Al.sub.2O.sub.3 foam substrate was obtained. After that, before being compounded with a matrix material, a 200 nm thick WCu alloy film was sputtered onto the foamed graphene skeleton by magnetron sputtering method for surface modification according to step (5). (6) The foamed graphene skeleton with WCu alloy film was set in the mold, serving as a bulk reinforcement to be compounded with the matrix. (7) The thermally conductive foamed graphene skeleton was covered with a CuSi alloy having a volume that was twice the volume of the foamed graphene skeleton; wherein the mass fraction of Si was 15%. Next, the mold was placed in a heating furnace, at a temperature of about 1350 C. for 30 min under a high purity nitrogen atmosphere. A copper-matrix composite reinforced by the foamed graphene skeleton was obtained, and the thermal conductivity of the composite was 770 W/(m.Math.K).

Example 3: Copper-Matrix Composite Reinforced with Foamed Diamond/Graphene Skeleton

[0113] In this example of copper-matrix composite reinforced with a foamed diamond skeleton, a nickel foam with a pore size of 0.2 mm was used as a substrate. The volume fraction of the diamond foam reinforcement in composite was 30%. Firstly, according to step (1), the three-dimensional network substrate of the copper foam was cleaned. Then, according to step (2), a chromium film as an intermediate transition layer with a thickness of 50 nm, was deposited on the surface of the three-dimensional network of the foamed nickel skeleton by vacuum evaporation method. Afterwards, the substrate of the foamed skeleton was seeded with nano-crystalline and micro-crystalline diamond particles according to step (3). According to step (4), a diamond film was deposited by hot filament CVD, and deposition parameters were as follows: the filament-to-substrate distance was 6.0 mm; the substrate temperature was 850 C.; the filament temperature was 2200 C.; the deposition pressure was 3 kPa; the volume flow ratio of CH.sub.4/H.sub.2 was 1:99. The thickness of the as-deposited diamond film was kept at 300 m by tuning the deposition time. Hence, a three-dimensional network skeleton of the diamond coated copper foam substrate was obtained. Next, a graphene layer was in-situ grown on the diamond surface by plasma-assisted chemical vapor deposition technique. During the deposition process, plasma was applied to the substrate of the foamed skeleton to assist the graphene growth. The plasma was confined to the near surface of the diamond foam by adding a magnetic field at the bottom of the substrate, reinforcing the plasma bombardment on the surface of the foamed skeleton and making the graphene grow perpendicular to the surface of substrate. A foamed skeleton with a large amount of thermally conductive graphene-coated diamond particles in pores and a large amount graphene walls grown on the skeleton surface was obtained. Deposition parameters were as follows: the substrate temperature was 900 C.; the deposition pressure was 5.0 kPa; the volume flow ratio of CH.sub.4/H.sub.2 was 15:85; the plasma current density was 5 mA/cm.sup.2; the magnetic field intensity was 500 Gs. Meanwhile, the orientation of the graphene growth was controlled under the applied electric field to make graphene form graphene walls perpendicular to the surface of the substrate. The reinforcing layer of the graphene-coated diamond film was obtained, and a three-dimensional network skeleton of graphene-coated diamond on the nickel foam substrate was obtained. After that, according to step (5), before compounding with the matrix material, a chromium film was sputtered onto the foamed graphene skeleton by plating method for surface modification; wherein the thickness of the chromium film was 200 nm. (6) The foamed graphene skeleton coated with the chromium film was set in the mold, serving as a strip-like reinforcement to be compounded in the matrix in parallel arrangement. (7) The foamed skeleton with the graphene reinforcing layer was compounded with a copper matrix by vacuum gas pressure casting method. Deposition parameters were as follows: the preform of the foamed graphene skeleton was heated to 1020 C. for 1 h; the mold was heated to 840 C. for 1 h; a copper alloy (Brand T1) was melted at 1160 C. for 0.5 h to remove gas and slag. The copper alloy liquid was poured into the mold until the punch exceeded the sprue gate. After that, the mold was degassed by a die-casting vacuum machine. When the vacuum of the mold was less than 1000 Pa, the punch continued to pressurize, and the final casting pressure was 80 MPa. After holding the pressure for 2 min, the composite was removed from the mold. A copper alloy composite reinforced with the foamed graphene skeleton was obtained. The result of performance test: the overall thermal conductivity of the composite was 954 W/(m.Math.K).

Example 4: Aluminum Alloy Composite Reinforced with Foamed Diamond/Carbon Nanotube Skeleton

[0114] In this example of aluminum alloy composite reinforced with foamed diamond/carbon nanotube skeleton, a tungsten foam with a pore diameter of 1 mm was used as the substrate. The volume fraction of the diamond foam reinforcement in composite was 40%. Firstly, according to step (1), the three-dimensional network substrate of the tungsten foam was cleaned. A graphene film was in-situ deposited directly on the surface of the diamond foam without an intermediate transition layer by CVD. Afterwards, the substrate of the foamed skeleton was seeded with nano-crystalline and micro-crystalline diamond particles according to step (3). According to step (4), a diamond film was deposited by hot filament CVD and process parameters were as follows: the filament-to-substrate distance was 6.0 mm; the substrate temperature was 900 C.; the filament temperature was 2200 C.; the deposition pressure was 3.0 kPa; the volume flow ratio of CH.sub.4/H.sub.2 was 1:99. The thickness of the as-deposited diamond film was kept at 300 m by tuning the deposition time. A three-dimensional network skeleton of diamond coated tungsten foam substrate was then obtained. A layer of nickel was sputtered on the surface of the diamond by magnetron sputtering, and then carbon nanotubes were then catalytically grown on the surface of the diamond by plasma-assisted chemical vapor deposition. Meanwhile, the orientation of the graphene growth was controlled under the applied electric field to make carbon nanotube form carbon nanotube forests perpendicular to the surface of substrate. The reinforcing layer of carbon nanotubes coated foamed substrate was thus obtained. Process parameter were as follows: the mass flow ratio of CH.sub.4/H.sub.2 was 25:75; the growth temperature was 600 C.; the growth pressure was 3000 Pa; the plasma current density was 5 mA/cm.sup.2; the magnetic field intensity in the deposition area was 350 Gs. A three-dimensional network skeleton of carbon nanotubes coated diamond on tungsten foam was obtained after 40 min deposition. Then, according to step (5), before the compounding process, a copper layer was plated on the surface of foamed diamond skeleton with perpendicular carbon nanotubes by electroplating method; wherein the thickness of the copper layer was 500 nm. (6) The foamed diamond skeleton plated with copper layer was set in the mold, serving as a bulk reinforcement to be compounded with the matrix; (7) The foamed skeleton with diamond/carbon nanotubes reinforcing layer was compounded with aluminum matrix by vacuum pressure casting method, and process parameters were as follows: the vacuum chamber pressure was 5 Pa; the network skeleton and the molding die were heated to 720 C. for 2 h; the aluminum alloy (grade 6063) which was melted at 760 C. for 1 h; the infiltration pressure was 8 MPa. The pressure was kept until the temperature was cooled to 400 C., and the composite was removed from the mold. An aluminum-matrix composite reinforced by the skeleton of diamond/carbon nanotube coated on tungsten foam substrate was obtained. The result of performance test: the overall thermal conductivity of the composite was 976 W/(m.Math.K).

Example 5: Magnesium Alloy Composite Reinforced with Foamed Graphene/Carbon Nanotube Skeleton

[0115] In this example of magnesium-matrix composite reinforced with a foamed graphene skeleton, tungsten foam with pore size of 1 mm was used as a substrate. The volume fraction of graphene foam reinforcement in composite was 30%. Firstly, according to step (1), the three-dimensional network substrate of tungsten foam was cleaned. Next, graphene film was in-situ deposited directly on the surface of the diamond foam without an intermediate transition layer by chemical vapor deposition. Then, according to the step (4), a graphene film was deposited by hot wall CVD. Process parameters were as follows: the sample was heated to 950 C. (heating rate: 33 C./min) in an atmosphere of H.sub.2 and Ar (flow rate: 200 mL/min and 500 mL/min); after the furnace temperature was raised to 950 C., the heat treatment was carried out for 10 min; after the heat treatment was over, a mixture of CH.sub.4, H.sub.2 and Ar was introduced (flow rate were respectively 5 mL/min, 200 mL/min and 500 mL/min), and the graphene was grown; cooling rate was 100 C./min. The average thickness of graphene film was 1.7 nm. A three-dimensional network skeleton of graphene on tungsten foam substrate was thus obtained. Next, a layer of nickel was sputtered on the surface of the graphene through magnetron sputtering. Then, the carbon nanotubes were catalytically grown on the surface of the graphene by plasma-assisted chemical vapor deposition. Meanwhile, the orientation of the carbon nanotube growth was controlled under the applied electric field to make carbon nanotube form carbon nanotube forests perpendicular to the substrate surface. The reinforcing layer of carbon nanotubes coated graphene film was thus obtained, and process parameter were as follows: the mass flow ratio of CH.sub.4/H.sub.2 was 10%; the growth temperature was 600 C.; the growth pressure was 3000 Pa; the plasma current density was 5 mA/cm.sup.2; the magnetic field intensity in the deposition area was 500 Gs; the growth time was 30 min. A three-dimensional network skeleton of carbon nanotubes coated graphene on tungsten foam substrate was then obtained. Then, according to step (5), before the compounding process, a titanium layer was evaporated onto the surface of foamed skeleton by vacuum evaporation method for surface modification; wherein the thickness of the layer was 500 nm. (6) The carbon nanotubes-coated foamed graphene skeleton plated by titanium was placed in a mold, serving as a bulk reinforcement to be compounded with a matrix. (7) The foamed skeleton with graphene reinforcing layer was compounded with a magnesium alloy matrix by vacuum pressure casting method, and process parameters were as follows: the vacuum chamber pressure was 5 Pa; the network skeleton and the mold were heated at 700 C. for 2 h; the magnesium alloy was melted at 750 C. for 1 h; the infiltration pressure was 8 MPa. The pressure was kept until the temperature was cooled to 400 C., and the composite was removed from the mold. A magnesium-matrix composite reinforced by the skeleton of carbon nanotube coated on graphene foam was thus obtained. The result of performance test: the overall thermal conductivity of the composite was 540 W/(m.Math.K).

Example 6: Silver-Matrix Composite Reinforced with Foamed Diamond/Graphene/Carbon Nanotube Skeleton

[0116] In this example of silver-matrix composite reinforced with a foamed diamond/graphene/carbon nanotube skeleton, a copper foam with a pore diameter of 0.3 mm was used as the substrate. The volume fraction of the diamond foam reinforcement in composite was 10%. Firstly, according to step (1), the three-dimensional network substrate of a copper foam was cleaned. Then, according to step (2), a molybdenum film, as an intermediate transition layer and with a thickness of 50 nm, was deposited on the surface of the three-dimensional network foamed copper skeleton by magnetron sputtering technique. Next, according to step (3), the substrate of the foamed skeleton was seeded with nano-crystalline and micro-crystalline diamond particles. In Step (4), a diamond film was deposited by hot filament CVD, and process parameter were as follows: the filament-to-substrate distance was 6 mm; the substrate temperature was 850 C.; the filament temperature was 2200 C.; the deposition pressure was 3 kPa; the volume flow ratio of CH.sub.4/H.sub.2 was 1:99. The thickness of the deposited diamond film can be controlled at 60 m by tuning the CVD deposition time. A three-dimensional network skeleton of a diamond coated copper foam substrate was obtained. Then, a graphene film was deposited by hot wall CVD, and process parameters were as follows: the sample was heated to 950 C. (heating rate: 33 C./min) in an atmosphere of H.sub.2 and Ar (flow rate: 200 mL/min and 500 mL/min), and was heat treated for 10 min at 950 C.; after the heat treatment was over, a mixture of CH.sub.4, H.sub.2 and Ar was introduced (flow rate were respectively 5 mL/min, 200 mL/min and 500 mL/min), and the graphene was grown; cooling rate was 100 C./min; the growth time was 50 min. A three-dimensional network skeleton of diamond/graphene on copper foam substrate was obtained. Next, a layer of nickel was sputtered on the surface of the graphene through magnetron sputtering. Then, carbon nanotubes were catalytically grown on the surface of the graphene by plasma-assisted chemical vapor deposition. Meanwhile, the orientation of the carbon nanotubes growth was controlled by an applied electric field, leading to carbon nanotube form carbon nanotube forests perpendicular to the surface of graphene. A three-dimensional network skeleton of diamond/grapheme/carbon nanotube-coated copper foam substrate was thus obtained, and process parameters were as follows: the mass flow ratio of CH.sub.4/H.sub.2 was 10%; the growth temperature was 600 C.; the growth pressure was 3000 Pa; the plasma current density was 5 mA/cm.sup.2; the magnetic field intensity in the deposition area was 30 Gs; the growth time was 60 min. Then, according to step (5), before the compounding process, a tungsten layer was evaporated onto the surface of foamed diamond skeleton by vacuum evaporation method for surface modification; wherein the thickness of the layer was 150 nm. (6) The foamed diamond skeleton coated with a tungsten layer was placed in the mold, serving as a sheet-like reinforcement to be compounded with the matrix in parallel arrangement. (7) The foamed skeleton was covered with the silver alloy that was 2 times in the volume. Then, the mold was placed in a heating furnace, at a temperature of about 950 C. for 30 min under a high-purity nitrogen atmosphere. A silver-matrix composite reinforced with foamed diamond/graphene/carbon nanotube skeleton was obtained and the thermal conductivity of the composite was 697 W/(m.Math.K).

Example 7: Titanium-Matrix Composite Reinforced with Foamed Graphene Skeleton

[0117] In this example of titanium-matrix composite reinforced with a foamed graphene skeleton, porous ceramic SiC was used as a substrate having a pore diameter of 2 mm. The volume fraction of the foamed graphene reinforcement in composite was 15%. Firstly, the three-dimensional network substrate of a SiC foam was cleaned according to step (1). Then, according to step (2), a tungsten film, as an intermediate transition layer and with a thickness of 200 nm, was deposited on the surface of foamed aluminium oxide skeleton by magnetron sputtering technique. Afterwards, graphene was in-situ grown on the surface of substrate by plasma enhanced chemical vapor deposition. During the deposition process, plasma was applied to the substrate of the foamed skeleton to assist the graphene growth according to step (4). The plasma was confined to the near surface of the diamond foam by adding a magnetic field at the bottom of the substrate, reinforcing the plasma bombardment to the surface of the foamed skeleton and making the graphene growth perpendicular to the surface of the substrate. A large amount of graphene-coated diamond highly thermal conductivity particles and skeleton surface growth in the mesh was obtained.

[0118] The foam skeleton of a large number of graphene walls, the deposition parameters were as follows: the substrate temperature was 850 C.; the deposition pressure was 5.0 kPa; the volume flow ratio of CH.sub.4/H.sub.2 was 10:90; the plasma current density was 5 mA/cm.sup.2; the magnetic field intensity was 500 Gs. Meanwhile, the orientation of the graphene growth was controlled under the applied electric field to make graphene form graphene walls perpendicular to the surface of the substrate. A foamed graphene skeleton was then obtained. After that, before being compounded with the matrix material, WCu alloy film was sputtered onto the foamed graphene skeleton by magnetron sputtering method for surface modification according to step (5); wherein the thickness of WCu alloy film was 200 nm. (6) The foamed graphene skeleton coated with WCu alloy film was set in the mold, serving as a bulk reinforcement to be compounded with the matrix. (7) The highly thermal conductive foamed graphene skeleton was covered with the titanium alloy having a volume that was twice the volume of the foamed graphene skeleton. Then, the mold was placed in a heating furnace, at a temperature of about 1750 C. for 30 min under a high-purity nitrogen atmosphere. A titanium-matrix composite reinforced with the foamed graphene skeleton was obtained. The thermal conductivity of the composite was 728 W/(m.Math.K).

Example 8: Magnesium-Matrix Composite Reinforced with Foamed Diamond Skeleton

[0119] In this example of magnesium-matrix composite reinforced with a foamed diamond skeleton, a carbon foam was used as a substrate having a pore diameter of 0.35 mm. The volume fraction of the foamed diamond reinforcement in composite was 30%. Firstly, the three-dimensional network substrate of carbon foam was cleaned according to step (1). Then, according to step (2), a molybdenum film, as an intermediate transition layer and with a thickness of 50 nm, was deposited on the surface of three-dimensional network-like foamed carbon skeleton by magnetron sputtering technique. Afterwards, the substrate of foamed skeleton was seeded with nano-crystalline and micro-crystalline diamond particles according to step (3). According to step (4), a diamond film was deposited by hot filament CVD. Deposition process parameters were as follows: the filament-to-substrate distance was 6 mm; the substrate temperature was 800 C.; the deposition pressure was 3 kPa; the volume flow ratio of CH.sub.4/H.sub.2 was 1:99. The thickness of the as-deposited diamond film was kept at 300 m by tuning the deposition time. A three-dimensional network skeleton of diamond coated carbon foam substrate was obtained. After that, before being compounded with a matrix material, a tungsten film was in-situ evaporated on the surface of the foamed diamond skeleton by vacuum evaporation method for surface modification according to step (5); wherein the thickness of tungsten film was 100 nm. (6) The foamed diamond skeleton coated with the tungsten film was placed in the mold, serving as a sheet-like reinforcement to be compounded with a matrix in parallel arrangement. (7) Foamed diamond skeleton was compounded with magnesium matrix by vacuum gas pressure casting method. Process parameters were as follows: the pressure in vacuum chamber was 5 Pa; the heating temperature of the foamed skeleton and the mold was 700 C. for 2 h; the heating temperature of the magnesium alloy was 750 C. for 1 h; the infiltration pressure was 8 MPa. The pressure was kept until the temperature was cooled to 400 C., and the composite was removed from the mold. A magnesium-matrix composite reinforced by the skeleton of diamond coated carbon foam substrate was obtained. The result of performance test: the overall thermal conductivity of the composite was 875 W/(m.Math.K).

Example 9: Aluminum-Matrix Composite Reinforced with Foamed Boron-Doped Diamond Skeleton

[0120] In this example of aluminum-matrix composite reinforced with a foamed boron-doped diamond skeleton, a copper foam was used as a substrate having a pore diameter of 0.3 mm. The volume fraction of the foamed diamond reinforcement in composite was 20%. Firstly, the three-dimensional network substrate of the copper foam was cleaned according to step (1). Then, according to step (2), a chromium film, as an intermediate transition layer and with a thickness of 50 nm, was deposited on the surface of three-dimensional network-like foamed copper skeleton by magnetron sputtering technique. Afterwards, the substrate of the foamed skeleton was seeded with nano-crystalline and micro-crystalline diamond particles according to step (3). According to step (4), a diamond film was deposited by hot filament CVD. Deposition process parameters were as follows: the filament-to-substrate distance was 6 mm; the substrate temperature was 800 C.; the filament temperature was 2200 C.; the deposition pressure was 3 kPa; the source of boron was B.sub.2H.sub.6, and the volume flow ratio of B.sub.2H.sub.6/CH.sub.4/H.sub.2 was 0.2:1:99. The thickness of the as-deposited boron-doped diamond film was kept at 60 m by tuning the deposition time. A three-dimensional network skeleton of a diamond coated copper foam substrate was obtained. After that, before being compounded with a matrix material, a nickel film was sputtered onto the foamed diamond skeleton by magnetron sputtering method for surface modification according to step (5); wherein the thickness of nickel film was 10 nm. (6) The as-prepared sample in the step (5) was put into a tube furnace with a vacuum device for catalysis. The catalytic temperature was set to 900 C.; the atmosphere for catalytic etching was nitrogen; the pressure of catalytic etching was 1 atm; the catalytic etching time was 3 h. A foamed boron-doped diamond skeleton with pores and sharp cones on the surface was obtained. (7) The as-prepared foamed boron-doped diamond skeleton was placed in the mold, serving as a sheet-like reinforcement to be compounded with a matrix in parallel arrangement. (8) The foamed boron-doped diamond skeleton was compounded with pure aluminum matrix by vacuum pressure infiltration method. Process parameters were as follows: the pressure in vacuum chamber was 5 Pa; the heating temperature of the foamed skeleton and the mold was 700 C. for 2 h; the heating temperature of the pure aluminum was 720 C. for 0.5 h; the infiltration pressure was set to 8 MPa. The pressure was kept until the temperature was cooled to 400 C., and the composite was removed from the mold. An aluminum-matrix composite reinforced with the foamed boron-doped diamond skeleton was obtained. The result of performance test: the overall thermal conductivity of the composite was 676 W/(m.Math.K).

[0121] In this invention, the embodiments of polymer matrix composites is according to the process or steps as follows:

[0122] (1) A foamed skeleton is placed in ethanol for ultrasonic cleaning, and dried for use.

[0123] (2) An intermediate transition layer is deposited on the surface of the foamed skeleton through a method selected from one of electroplating, electroless plating, evaporation, magnetron sputtering, chemical vapor deposition and physical vapor deposition; wherein the intermediate transition layer is selected from one of nickel, copper, tungsten, molybdenum, titanium, silver, chromium, or a composite metal layer thereof.

[0124] (3) The mixture of nano-crystalline and micro-crystalline diamond particles, the foamed skeleton substrate, and the solvent are mixed and heated to boil. Then, the mixture is under high-power ultrasonic oscillation for 30 minutes. After ultrasonic dispersion uniformly, the foamed skeleton is taken out and dried. The substrate of the foamed skeleton with a large amount of nano-crystalline and micro-crystalline diamond particles in pores was obtained.

[0125] (4) A continuous and dense reinforcing layer is deposited on the metal substrates by hot filament chemical vapor deposition; wherein the reinforcing layer is selected from at least one of diamond film, graphene film, carbon nanotube film, graphene coated diamond, carbon nanotube coated diamond, carbon nanotube coated graphene and carbon nanotube/graphene coated diamond.

[0126] (5) The distribution of foamed skeleton reinforcement in a matrix after surface modification can be according to the following three arrangements. a. The foamed skeleton serves as a bulk reinforcement to be compounded with a matrix. The whole composite presents an interpenetrated network configuration of highly thermal conductivity reinforcing layer/polymer. b. The foamed skeleton serves as a sheet-like reinforcement to be compounded with a matrix. The distribution of reinforcement in the matrix is in parallel arrangement. c. The foamed skeleton serves as a strip-like reinforcement to be compounded with a matrix. The distribution of reinforcement in the matrix is in parallel arrangement.

[0127] (6) The impregnation and curing techniques are carried out to integrate the foamed skeleton with the reinforcing layer into polymer matrix.

Example 10: (Diamond)

[0128] In this example of epoxy-matrix composite reinforced with a foamed diamond skeleton, a copper foam was used as a substrate having a pore diameter of 0.2 mm. The volume fraction of the foamed diamond reinforcement in the composite was 20%. Firstly, a three-dimensional network substrate of a copper foam was cleaned according to step (1). Then, according to step (2), a molybdenum film, as an intermediate transition layer and with a thickness of 50 nm, was deposited on the surface of the three-dimensional network-like foamed copper skeleton by magnetron sputtering technique. Afterwards, the substrate of the foamed skeleton was seeded with nano-crystalline and micro-crystalline diamond particles according to step (3). According to step (4), a diamond film was deposited by hot filament CVD. Deposition process parameters were as follows: the filament-to-substrate distance was 6 mm; the substrate temperature was 800 C.; the deposition pressure was 3 kPa; the volume flow ratio of CH.sub.4/H.sub.2 was 1:99. The thickness of the as-deposited diamond film was kept at 160 m by tuning the deposition time. A three-dimensional network skeleton of diamond coated copper foam substrate was hence obtained. (5) The foamed diamond skeleton was set in the mold, serving as a sheet-like reinforcement to be compounded with the matrix in parallel arrangement. (6) A precursor solution of Bisphenol F epoxy (the curing agent was diaminodiphenyl methane (DDM)) was dripped into the foamed diamond skeleton at volume ratio of 1:1 at 80 C. The foamed diamond skeleton was fully infiltrated by the precursor solution of the epoxy resin, and a mixture was obtained. The above mixture was degassed under vacuum for 2 h to remove the bubbles inside, making the precursor solution of the epoxy better impregnate to the pores of the diamond network. The mixture was step cured at 100 C. for 2 h and then at 160 C. for 4 h. Finally, after being cooled to room temperature, a bisphenol F epoxy resin composite reinforced with the foamed diamond skeleton was obtained. The thermal conductivity of the composite was 349 W/(m.Math.K).

Example 11: (Graphene Wall)

[0129] In this example of silicone rubber composite reinforced with a foamed graphene skeleton, a porous ceramic Al.sub.2O.sub.3 was used as a substrate having a pore diameter of 2 mm. The volume fraction of the foamed graphene reinforcement in composite was 10%. Firstly, the three-dimensional network substrate of the Al.sub.2O.sub.3 foam was cleaned according to step (1). Then, according to step (4), graphene was in-situ grown on the surface of substrate by plasma enhanced chemical vapor deposition. During the deposition process, plasma was applied to the substrate of foamed skeleton to assist the graphene growth. The plasma was confined to the near surface of the diamond foam by adding a magnetic field at the bottom of the substrate, reinforcing the plasma bombardment to the surface of foamed skeleton and making the graphene growth perpendicular to the surface of substrate. A foamed skeleton with a large amount of highly thermal conductive graphene-coated diamond particles in pores and a large amount graphene walls grown on the skeleton surface was obtained. Deposition parameters were as follows: the substrate temperature was 800 C.; the deposition pressure was 5.0 kPa; the volume flow ratio of CH.sub.4/H.sub.2 was 30:70; the plasma current density was 5 mA/cm.sup.2; the magnetic field intensity was 500 Gs; the deposition time was 1 h. Meanwhile, the orientation of the graphene growth was controlled under the applied electric field to make graphene form graphene walls perpendicular to the surface of substrate. A three-dimensional network skeleton of graphene coated on the Al.sub.2O.sub.3 foam substrate was obtained. After that, before being compounded with a matrix material, WCu alloy film was sputtered onto the foamed graphene skeleton by magnetron sputtering method for surface modification according to step (5); wherein the thickness of WCu alloy film was 200 nm. (6) The foamed graphene skeleton coated with WCu alloy film was set in the mold, serving as a bulk reinforcement to be compounded with the matrix. (7) A precursor solution of silicone rubber was dripped into the foamed graphene skeleton at a volume ratio of 1:2. The foamed graphene skeleton was fully infiltrated by the precursor solution of the silicone rubber, and a mixture was obtained. The above mixture was degassed under vacuum for 2 h to remove the solvent and bubbles inside, making the precursor solution of silicone rubber to be better impregnated into the pores of the graphene network. The mixture was cured at 80 C. for 4 h. A silicone rubber composite reinforced with a foamed graphene skeleton was obtained. The thermal conductivity of the composite was 278 W/(m.Math.K).

Example 12: (Graphene Coated Diamond)

[0130] In this example of polymethyl methacrylate (PMMA) composite reinforced with a foamed diamond skeleton, a nickel foam was used as a substrate having a pore diameter of 0.3 mm. The volume fraction of the foamed diamond reinforcement in composite was 30%. Firstly, the three-dimensional network substrate of the nickel foam was cleaned according to step (1). Then, according to step (2), a chromium film, as an intermediate transition layer and with a thickness of 300 nm, was deposited on the surface of three-dimensional network-like foamed nickel skeleton by evaporation method. Afterwards, according to step (3), the substrate of foamed skeleton was seeded with nano-crystalline and micro-crystalline diamond particles. (4) Diamond film was deposited by hot filament CVD. Deposition process parameters were as follows: the filament-to-substrate distance was 6 mm; the substrate temperature was 850 C.; the filament temperature was 2200 C.; the deposition pressure was 3 kPa; the volume flow ratio of CH.sub.4/H.sub.2 was 1:99. The thickness of the as-deposited diamond film was kept at 280 m. A three-dimensional network skeleton of diamond coated nickel foam substrate was thus obtained. Next, graphene was in-situ grown on the diamond surface by plasma enhanced chemical vapor deposition. During the deposition process, plasma was applied to the substrate of the foamed skeleton to assist the graphene growth. The plasma was confined to the near surface of the diamond foam by adding a magnetic field at the bottom of the substrate to increase the plasma bombardment to the surface of the foamed skeleton and making the graphene growth perpendicular to the surface of substrate. A foamed skeleton with a large amount of highly thermal conductive graphene-coated diamond particles in pores and a large amount graphene walls grown on the skeleton surface was obtained. Deposition parameters were as follows: the substrate temperature was 800 C.; the deposition pressure was 5.0 kPa; the volume flow ratio of CH.sub.4/H.sub.2 was 25:75; the plasma current density was 15 mA/cm.sup.2; the magnetic field intensity was 500 Gs; the deposition time was 30 min. Meanwhile, the orientation of the graphene growth was controlled under the applied electric field to make graphene form graphene wall perpendicular to the surface of substrate. A reinforcing layer of graphene coated diamond film was obtained, and a three-dimensional network skeleton of graphene coated diamond on the nickel foam substrate was obtained. According to step (6), the foamed graphene skeleton was placed in the mold, serving as a strip-like reinforcement to be compounded with a matrix in parallel arrangement. (7) A PMMA chloroform solution was dripped into the foamed graphene skeleton at volume ratio of 1:5. The foamed diamond skeleton was fully infiltrated by the PMMA solution, and a mixture was obtained. The above mixture was dried under vacuum oven at 60 C. for 24 h to remove the chloroform solvent. The mixture was cured at 110 C. for 1 h. Finally, after being cooled to room temperature, a PMMA composite reinforced with foamed skeleton of graphene-coated diamond was obtained. The thermal conductivity of the composite was 408 W/(m.Math.K).

Example 13: Diamond/Carbon Nanotube

[0131] In this example of epoxy resin composite reinforced with foamed diamond/carbon nanotube skeleton, a tungsten foam was used as a substrate having a pore diameter of 1 mm. The volume fraction of the foamed diamond reinforcement in composite was 50%. Firstly, the three-dimensional network substrate of the tungsten foam was cleaned according to step (1). Afterwards, the substrate of foamed skeleton was seeded with nano-crystalline and micro-crystalline diamond particles according to step (3). According to step (4), a diamond film was deposited by hot filament CVD. The deposition parameters were as follows: filament-to-substrate distance was 6 mm; substrate temperature was 900 C.; filament temperature was 2300 C.; deposition pressure was 3 kPa; the volume flow ratio of CH.sub.4/H.sub.2 was 1:99. The thickness of the as-deposited diamond film was 500 m, and a three-dimensional network skeleton of diamond on the tungsten foam substrate was obtained. Then, a nickel layer was sputtered onto the surface of the diamond through magnetron sputtering, and carbon nanotubes were then catalytically grown on the surface of the nickel by plasma-assisted chemical vapor deposition technique. Meanwhile, the orientation of the carbon nanotube growth was controlled under the applied electric field to make graphene form carbon nanotube forest perpendicular to the surface of substrate. The reinforcing layer of the carbon nanotube coated diamond film was obtained. The deposition parameters were as follows: the ratio of mass flow rate of methane and hydrogen was 25:75; the growth temperature was 600 C.; the growth pressure was 3 kPa; plasma current density was 5 mA/cm.sup.2; the magnetic field intensity was 350 Gs. A three-dimensional network foamed skeleton of carbon nanotube coated diamond on tungsten foam substrate was obtained. According to step (5), the foamed carbon nanotube/diamond skeleton was placed in a mold, serving as a bulk reinforcement to be compounded with a matrix. (6) A precursor solution of Bisphenol F epoxy resin (the curing agent was Diaminodiphenylmethane (DDM)) was dripped into the foamed diamond skeleton at volume ratio of 1:1. The foamed diamond skeleton was fully infiltrated by the precursor solution of the epoxy resin, and a mixture was obtained. Then the above mixture was degassed under vacuum for 2 h to remove the bubbles and make the precursor solution to be better impregnated into the pores of the diamond network. The mixture was step heated and cured at 100 C. for 2 h, and then raised to 160 C. for 4 h. After being cooled to room temperature, a bisphenol F epoxy resin composite reinforced with the foamed diamond/carbon nanotube skeleton was obtained, and the thermal conductivity of the composite was 536 W/(m.Math.K).

Example 14: Graphene/Carbon Nanotube

[0132] In this example of silicone rubber composite reinforced with a foamed graphene/carbon nanotube skeleton, a nickel-iron foam was used as a substrate having a pore diameter of 1 mm. The volume fraction of the foamed graphene reinforcement was 7%. Firstly, the three-dimensional network of nickel-iron foam substrate was cleaned according to step (1). Then, the graphene film was in-situ grown through CVD directly without an intermediate transition layer. Afterwards, the graphene film was deposited by hot wall CVD accordingly, and specifically: the sample was heated to 950 C. in an atmosphere of H.sub.2 and Ar (the flow rate of H.sub.2 and Ar was 200 mL/min and 500 mL/min respectively; the heating rate was 33 C./min), and was heat treated for 10 min after the furnace temperature was raised to 950 C. After the heat treatment, the mixture gas of CH.sub.4, H.sub.2 and Ar was introduced (flow rate: CH.sub.4 was 5 mL/min, H.sub.2 was 200 mL/min and Ar was 500 mL/min respectively), and the graphene was grown. The cooling rate was 100 C./min and deposition time was 2 h. A three-dimensional network skeleton of graphene on the nickel-iron substrate was obtained. Next, a layer of nickel was sputtered onto the surface of the graphene through magnetron sputtering technique. Then carbon nanotubes were catalytically grown on the surface of the graphene by plasma-assisted chemical vapor deposition technique. Meanwhile, the orientation of the carbon nanotube growth was controlled under the applied electric field to make graphene form carbon nanotube forests perpendicular to the surface of the graphene. The reinforcing layer of carbon nanotube coated graphene film was obtained, and the deposition parameters were as follows: mass flow rate of methane was 8%; growth temperature was 600 C.; growth pressure was 3000 Pa; plasma current density was 5 mA/cm.sup.2; magnetic field intensity was 500 Gs; growth time was 30 min. A three-dimensional network skeleton of carbon nanotube coated graphene on the nickel-iron foam substrate was obtained. The carbon nanotube coated foamed diamond skeleton was placed in the mold, serving as a bulk reinforcement to be compounded with the matrix according to step (5). (7) Impregnation curing was used to perform compounding through: a) Preparation of silicone rubber precursor solution: weighing 20 g silicone rubber precursor, mixing it with a curing agent at mass ratio of 10:1, and the mixture was mixed with an organic solvent ethyl acetate at a mass ratio of 1:9. Then stirring vigorously for about 5 min, and the mixture was degassed for 5 min to remove bubbles therein. Finally, an ethyl acetate solution of the silicone rubber precursor was obtained. b) Mixing: the three-dimensional network skeleton of graphene/carbon nanotube was placed in the mold, and the silicone rubber precursor solution was dropped into it at volume ratio of 2:1, so that the solution can fully infiltrate into the macroscopic diamond to obtain the mixture. c) Vacuum treatment: the above mixture was degassed under vacuum for 2 h to remove the solvent and bubbles and make the silicone rubber precursor solution better impregnated into the pores of the diamond network. d) After being heated to 80 C. and cured for 4 h, the silicone rubber composite reinforced with the foamed graphene/carbon nanotube skeleton was obtained, and the thermal conductivity of the composite was 254 W/(m.Math.K).

Example 15: PMMA Composite Reinforced with Foamed Diamond/Graphene/Carbon Nanotube Skeleton

[0133] In this example of PMMA composite reinforced with foamed diamond/graphene/carbon nanotube skeleton, a copper foam was used as a substrate having a pore diameter of 0.3 mm. The volume fraction of the foamed graphene reinforcement was 40%. Firstly, the copper foam three-dimensional network substrate was cleaned according to step (1). Then, according to step (2), a molybdenum film, as an intermediate transition layer and with a thickness of 50 nm, was deposited on the surface of three dimensional network skeleton of the copper foam by magnetron sputtering technique. Then, according to step (3), the foamed skeleton substrate with a large amount of nano-crystalline and micro-crystalline diamond particles in pores was obtained. According to step (4), a diamond film was deposited by hot filament CVD. The deposition parameters were as follows: filament-to-substrate distance was 6 mm; substrate temperature was 800 C.; hot filament temperature was 2200 C.; deposition pressure was 3 kPa; the volume flow ratio of CH.sub.4/H.sub.2 was 1:99, the thickness of the as-deposited diamond film can be controlled at 800 m by tuning the CVD deposition time, and a three-dimensional network skeleton of diamond on the copper foam substrate was obtained. Then the graphene film was deposited by hot wall CVD, and specifically: the sample was heated to 950 C. in an atmosphere of H.sub.2 and Ar (flow rate: H.sub.2 was 200 mL/min and Ar was 500 mL/min respectively, heating rate was 33 C./min), and was heat treated for 10 min after the furnace temperature was raised to 950 C.; after the heat treatment, the mixture gas of CH.sub.4, H.sub.2 and Ar was introduced (flow rate: CH.sub.4 was 5 mL/min, H.sub.2 was 200 mL/min and Ar was 500 mL/min respectively), and the graphene was grown; cooling rate was 100 C./min; deposition time was 3 h; and a three-dimensional network skeleton of diamond/graphene on the copper foam substrate was obtained. Then a layer of nickel was deposited onto the surface of the graphene through magnetron sputtering technique. Next, carbon nanotubes were catalytically grown on the surface of the graphene by plasma-assisted chemical vapor deposition technique. Meanwhile, the orientation of the carbon nanotube growth was controlled by the applied electric field to form carbon nanotube forests perpendicular to the surface of graphene. Then the three-dimensional network skeleton of diamond/graphene/carbon nanotubes on the copper foam substrate was obtained. The deposition parameters were as follows: mass flow rate of methane was 10%; growth temperature was 600 C.; growth pressure was 3000 Pa; plasma current density was 5 mA/cm.sup.2; magnetic field intensity was 500 Gs; growth time was 2 h. After that, before being compounded with a matrix material, a layer of tungsten film was in-situ evaporated onto the surface of foamed diamond skeleton for surface modification by vacuum evaporation method according to step (5). (6) The foamed diamond skeleton coated with tungsten film was placed in a mold to serve as a sheet-like reinforcement to be compounded with a matrix in parallel arrangement. (7) A polymethyl methacrylate (PMMA) chloroform solution was dripped at a volume ratio of 1:1, making the solution fully infiltrate into the foamed diamond skeleton to obtain a mixture. The above mixture was dried under vacuum oven at 60 C. for 24 h to remove the chloroform solvent, and was then heated to 110 C. After being kept for 1 h, then the sample was cooled to room temperature. Finally, the PMMA composite reinforced with foamed diamond/graphene/carbon nanotube skeleton was obtained, and the thermal conductivity of this composite was 567 W/(m.Math.K).

[0134] In this invention, the embodiments of paraffin wax matrix composites were prepared according to the process or steps as follows:

[0135] (1) A foamed skeleton is placed in ethanol for ultrasonic cleaning, and dried for use.

[0136] (2) An intermediate transition layer is deposited on the surface of the foamed skeleton through a method selected from one of electroplating, electroless plating, evaporation, magnetron sputtering, chemical vapor deposition and physical vapor deposition; wherein the intermediate transition layer is selected from one of nickel, copper, tungsten, molybdenum, titanium, silver, chromium, or a composite metal layer.

[0137] (3) The nano-crystalline and micro-crystalline diamond mixture particles, the foamed skeleton substrate, and the solvent are mixed and heated to boil. Then, the mixture is cleaned under the high-power ultrasonic oscillation for 30 minutes. After ultrasonic dispersion uniformly, the foamed skeleton is taken out and dried. The substrate of the foamed skeleton with a large amount of nano-crystalline and micro-crystalline diamond particles in pores was obtained.

[0138] (4) A continuous and dense reinforcing layer is deposited on the metal substrates by hot filament chemical vapor deposition; wherein the reinforcing layer is selected from at least one of diamond film, graphene film, carbon nanotube film, graphene coated diamond, carbon nanotube coated diamond, carbon nanotube coated graphene and carbon nanotube/graphene coated diamond.

[0139] (5) The foamed skeleton reinforcement can be distributed in a matrix after surface modification according to the following three arrangements:

[0140] a. The foamed skeleton serves as a bulk reinforcement to be compounded with a phase change material. The whole composite presents an interpenetrated network configuration of highly thermal conductivity reinforcing layer/phase change material.

[0141] b. The foamed diamond skeleton serves as a sheet-like reinforcement to be compounded with a phase change material. The reinforcement is arranged in the matrix in parallel.

[0142] c. The foamed diamond skeleton serves as a strip-like reinforcement to be compounded with a phase change material. The reinforcement is arranged in the matrix in parallel.

[0143] (6) The foamed skeleton with the reinforcing layer is compounded with a phase change material through vacuum impregnation and curing, or other techniques.

Example 16: Paraffin Phase Change Materials Reinforced with Diamond Foam

[0144] In this example, copper foam was used as a substrate having a pore diameter of 0.3 mm and a porosity of 20%, the volume fraction of the foamed diamond reinforcement in composite was 40%. Firstly, the three-dimensional network of copper foam substrate was cleaned according to step (1). Then, according to step (2), a chromium film, as an intermediate transition layer and with a thickness of 50 nm, was deposited on the surface of three dimensional network foamed copper skeleton by magnetron sputtering technique. And according to step (3), the foamed skeleton substrate with a large amount of nano-crystalline and micro-crystalline diamond particles in pores was obtained. According to step (4), a diamond film was deposited by hot filament CVD. The deposition parameters were as follows: filament-to-substrate distance was 6.0 mm; substrate temperature was 800 C.; filament temperature was 2200 C.; deposition pressure was 3.0 kPa; the volume flow ratio of CH.sub.4/H.sub.2 was 1:99. The thickness of the diamond film can be controlled at 30 m. Then the three dimensional network skeleton of diamond on the copper foam substrate was obtained. (5) The foamed diamond skeleton was placed in a mold and served as a sheet-like reinforcement to be compounded with a matrix in parallel arrangement. (7) The foamed diamond skeleton was placed into paraffin at a volume ratio of 1:5 at 90 C., after the paraffin fully infiltrated into the foamed diamond skeleton, a mixture was obtained. The above mixture was degassed under vacuum for 0.5 h at 100 C. to remove the bubbles therein, and making the paraffin to better impregnate into the pores of the diamond network. The temperature was continuously held for 1 h at 100 C. After being cooled to room temperature, the paraffin phase-change energy-storage composites reinforced with foamed diamond skeleton was obtained, and the thermal conductivity of the composite was 19.78 W/(m.Math.K).

Example 17: Paraffin Phase Change Materials Reinforced with Diamond Foam

[0145] In this example, copper foam was used as a substrate having a pore diameter of 0.2 mm and a porosity of 50%. The volume fraction of foamed diamond reinforcement in composite was 20%. Firstly, the three-dimensional network of a copper foam substrate was cleaned according to step (1). Then, according to step (2), a chromium film, as an intermediate transition layer and with a thickness of 50 nm, was deposited on the surface of three-dimensional network foamed copper skeleton by magnetron sputtering technique. And according to step (3), the foamed skeleton substrate with a large amount of nano-crystalline and micro-crystalline diamond particles in pores was obtained. According to step (4), a diamond film was deposited by hot filament CVD. The deposition parameters were as follows: filament-to-substrate distance was 6 mm; substrate temperature was 800 C.; filament temperature was 2200 C.; deposition pressure was 3 kPa; the volume flow ratio of CH.sub.4/H.sub.2 was 1:99. The thickness of the diamond film was controlled at 100 m. Then a three-dimensional network diamond skeleton on the copper foam substrate was obtained. (5) The foamed diamond skeleton was placed in a mold and served as a sheet-like reinforcement to be compounded with a matrix in parallel arrangement. (7) The foamed diamond skeleton was placed into the paraffin at a volume ratio of 1:5 at 90 C. After the paraffin fully infiltrated into the foamed diamond skeleton, a mixture was obtained. The above mixture was degassed under vacuum for 0.5 h at 100 C. to remove the bubbles therein and make the paraffin better impregnate into the pores of the diamond network. The sample was continuously kept for 1 h at 100 C. Finally, after being cooled to room temperature, the paraffin phase-change energy-storage composites reinforced with the foamed diamond skeleton was obtained. The thermal conductivity of this composite was 36.51 W/(m.Math.K).

Example 18: Paraffin Phase-Change Energy-Storage Materials Reinforced with Copper Foam

[0146] In this example, a copper foam was used as a substrate having a pore diameter of 0.2 mm and a porosity of 50%. The volume fraction of the foamed diamond reinforcement in the composite was 20%. Firstly, the three-dimensional network of copper foam substrate was cleaned according to step (1). (2) The foamed copper skeleton was placed in a mold and served as a sheet-like reinforcement to be compounded with a matrix in parallel arrangement. The foamed copper skeleton was placed into the paraffin at a volume ratio of 1:5 at 90 C. After the paraffin fully infiltrated into the foamed copper skeleton, a mixture was obtained. The above mixture was degassed in vacuum for 0.5 h at 100 C. to remove the bubbles therein and make the paraffin better impregnate into the pores of the diamond network. And the sample was continuously kept for 1 h at 100 C. Finally, after being cooled to room temperature, the paraffin phase change composites reinforced with copper foam was obtained. The thermal conductivity of the composite was 4.73 W/(m.Math.K).

Example 19: Paraffin Phase Change Composite Reinforced with Nickel Foam

[0147] Paraffin phase change composite reinforced with nickel foam in this example, nickel foam was used as a reinforcement having a pore size of 0.2 mm and a porosity of 50%. The volume fraction of nickel foam in composite was 20%. Firstly, the nickel foam was cleaned according to step (1). (2) Then, the nickel foam was set in the mold, serving as a sheet-like reinforcement to be compounded with the matrix in parallel arrangement. (6) Afterwards, the nickel foam was covered with paraffin that was 5 times in the volume at 90 C., making the paraffin wax fully infiltrate the nickel foam, and a mixture was obtained. The mixture was degassed under vacuum at 100 C. for 0.5 h, removing the bubbles and making the paraffin better impregnate to the pores of the nickel network. Next, the sample was kept at 100 C. for 1 h. Finally, after being cooled to room temperature, paraffin phase-change energy-storage composite reinforced with the nickel foam was obtained. The thermal conductivity of the composite was 1.64 W/(m.Math.K).

Example 20: Paraffin Phase-Change Energy-Storage Materials Reinforced with Diamond/Graphene Foam

[0148] In this example, a copper foam was used as a substrate having a pore size of 0.2 mm. The volume fraction of the diamond foam in the composite was 40%. Firstly, the three-dimensional network substrate of the copper foam was cleaned according to step (1). Then, a chromium film, as an intermediate transition layer and with a thickness of 300 nm, was in-situ evaporated on the surface of the copper foam substrate by vacuum evaporation method according to step (2). According to step (3), the foamed skeleton substrate with a large amount of nano-crystalline and micro-crystalline diamond particles in pores was obtained. According to step (4), diamond film was deposited by hot filament CVD. The deposition parameters were as follows: filament-to-substrate distance was 6 mm; substrate temperature was 850 C.; filament temperature was 2200 C.; deposition pressure was 3 kPa; the volume flow ratio of CH.sub.4/H.sub.2 was 1:99. The thickness of the as-deposited diamond film was controlled at 100 m. A three-dimensional network skeleton of diamond on the copper foam substrate was obtained. Afterwards, a graphene layer was in-situ grown on the surface of diamond substrate by plasma-assisted chemical vapor deposition technique. The plasma was confined to the near surface of the diamond by adding a magnetic field at the bottom of the substrate to increase the plasma bombardment to the surface of the substrate. Deposition parameters were as follows: the substrate temperature was 800 C.; the deposition pressure was 5.0 kPa; the volume flow ratio of CH.sub.4/H.sub.2 was 1:99; the plasma current density was 15 mA/cm.sup.2; the magnetic field intensity was 500 Gs; the deposition time was 30 min. At the same time, the orientation of the graphene growth was controlled by the applied electric field to make the graphene form graphene walls perpendicular to the surface of diamond. The reinforcing layer of the graphene-coated diamond film was obtained, and the three-dimensional network skeleton of the graphene coated diamond on the nickel foam substrate was obtained. (5) Then the foamed diamond skeleton coated by graphene was set in the mold, serving as a strip-like reinforcement to be compounded with the matrix in parallel arrangement. According to step (6), the foamed diamond skeleton was placed in the paraffin at a volume ratio of 2:3. Then the oven temperature was set to 90 C. After making the paraffin wax fully infiltrate the foamed diamond skeleton, a mixture was obtained. The mixture was degassed under vacuum at 100 C. for 0.5 h to remove the bubbles and make the paraffin better impregnated into the pores of the diamond network. Next, the sample was kept at 100 C. for 1 h. Finally, after being cooled to room temperature, a paraffin phase-change energy-storage composite reinforced with diamond/graphene foam was obtained. The thermal conductivity of the composite was 47.49 W/(m.Math.K).

Example 21: Paraffin Composite Reinforced with Diamond/Graphene/Carbon Nanotube Foam

[0149] In this example, a copper foam was used as a substrate having a pore size of 0.2 mm. The volume fraction of foamed diamond reinforcement in composite was 40%. Firstly, the copper foam substrate was cleaned according to step (1). Next, a chromium film, as an intermediate transition layer with a thickness of about 500 nm, was sputtered onto the surface of the three-dimensional network skeleton of the copper foam through magnetron sputtering method according to step (2). According to step (3), the foamed skeleton substrate with a large amount of nano-crystalline and micro-crystalline diamond particles in pores was obtained. According to step (4), a diamond film was deposited by hot filament CVD. The deposition parameters were as follows: filament-to-substrate distance was 6 mm; substrate temperature was 800 C.; filament temperature was 2200 C.; deposition pressure was 3 kPa; the volume flow ratio of CH.sub.4/H.sub.2 was 1:99. The thickness of the as-deposited diamond film was controlled at 500 m. After the deposition, a three-dimensional network skeleton of diamond on the copper foam substrate was obtained. Then a graphene film was then in-situ deposited on the surface of the diamond foam by hot-wall CVD. The process parameters were as follows: the sample was heated to 950 C. (heating rate was 33 C./min) in an atmosphere of H.sub.2 and Ar (flow rate: H.sub.2 was 200 mL/min and Ar was 500 mL/min respectively), and was heat treated for 10 min; then the mixture gas of CH.sub.4, H.sub.2 and Ar was introduced (flow rate: CH.sub.4 was 5 mL/min, H.sub.2 was 200 mL/min and Ar was 500 mL/min respectively) to grow the graphene. The cooling rate was 100 C. min; the growth time was 3 h. After the deposition, a three-dimensional network skeleton of diamond/graphene on copper foam was obtained. And a nickel film was deposited onto the surface of the graphene through magnetron sputtering. The carbon nanotubes were catalytically grown on the surface of the graphene by plasma-assisted chemical vapor deposition technique. Then the orientation of the carbon nanotube growth was controlled by the applied electric field to make carbon nanotubes form carbon nanotube forests perpendicular to the surface of graphene. A three-dimensional network skeleton of the foamed diamond/graphene/carbon nanotube was obtained. Deposition parameters were as follows: mass flow rate of methane was 10%; growth temperature was 600 C.; growth pressure was 3 kPa; plasma current density was 5 mA/cm.sup.2; magnetic field intensity was 500 Gs; growth time was 2 h. Then, the foamed skeleton coated with diamond/graphene/carbon nanotube on the surface was placed in a mold and served as a sheet-like reinforcement to be compounded with a matrix in parallel arrangement. According to step (6), the foamed skeleton was placed in paraffin at a volume ratio of 2:3. Then the oven temperature was set to 90 C., making the paraffin wax fully infiltrated the foamed diamond skeleton, and a mixture was obtained. The mixture was degassed under vacuum at 100 C. for 0.5 h, removing the bubbles and making the paraffin better impregnated to the pores of the diamond network. Finally, the sample was kept at 100 C. for 1 h and was then cooled to room temperature. A paraffin phase-change energy-storage material reinforced with foamed diamond/graphene/carbon nanotube skeleton was obtained, and the thermal conductivity of the composite was 79.38 W/(m.Math.K).

Example 22: Ba(OH).SUB.2..8H.SUB.2.O Phase Change Composite Reinforced with Foamed Diamond Skeleton

[0150] In this example, a porous nickel was used as a substrate having a pore diameter of 2 mm. The volume fraction of the foamed diamond reinforcement in composite was 40%. Firstly, the nickel foam substrate was cleaned according to step (1). Then, according to step (2), a tungsten film, as an intermediate transition layer with a thickness of about 200 nm, was deposited onto the surface of nickel foam substrate by magnetron sputtering method. According to step (3), the substrate of the foamed skeleton with a large amount of nano-crystalline and micro-crystalline diamond particles in pores was obtained. According to step (4), a diamond film was deposited by hot filament CVD. Deposition process parameters were as follows: the filament-to-substrate distance was 6 mm; the substrate temperature was 800 C.; the filament temperature was 2200 C.; the deposition pressure was 3 kPa; the volume flow ratio of CH.sub.4/H.sub.2 was 1:99. The thickness of the as-deposited diamond film was kept at 300 m. After the deposition, a three-dimensional network skeleton of diamond on the nickel foam substrate was obtained. Then, the foamed diamond skeleton was placed in a mold and served as a sheet-like reinforcement to be compounded with the matrix in parallel arrangement. According to step (6), the foamed diamond skeleton was put into Ba(OH).sub.2.8H.sub.2O at a volume ratio of 2:3. After making the paraffin wax fully infiltrated the foamed diamond skeleton, a mixture was obtained. The mixture was degassed under vacuum at 100 C. for 0.5 h to remove the bubbles and making the paraffin better impregnated into the pores of the diamond network. Finally, the sample was kept at 100 C. for 1 h and was then cooled to room temperature. A paraffin phase-change energy-storage material reinforced with the foamed diamond skeleton was obtained, and the thermal conductivity of the composite was 9.59 W/(m.Math.K).

Example 23: Epoxy Resin Composite Reinforced with Foamed Nitrogen-Doped Diamond Skeleton

[0151] In this example of epoxy resin composite reinforced with foamed nitrogen-doped diamond skeleton, a copper foam was used as a substrate having a pore diameter of 0.3 mm. The volume fraction of the diamond foam in the composite was 20%. Firstly, the copper foam substrate was cleaned according to step (1). Then, according to step (2), a chromium film, as an intermediate transition layer with a thickness of about 50 nm, was sputtered onto the surface of the copper foam substrate by magnetron sputtering method. According to step (3), the substrate of the foamed skeleton with a large amount of nano-crystalline and micro-crystalline diamond particles in pores was obtained. According to step (4), nitrogen-doped diamond film was deposited by hot filament CVD. Deposition process parameters were as follows: the filament-to-substrate distance was 6 mm; the substrate temperature was 2200 C.; the deposition pressure was 3 kPa; the nitrogen source was N.sub.2; the volume flow ratio of N.sub.2/CH.sub.4/H.sub.2 was 0.2:1:99. The thickness of the as-deposited diamond film was kept at 60 m by tuning the CVD diamond deposition time. A three-dimensional network skeleton of nitrogen-doped diamond on copper foam was obtained. Then, the foamed nitrogen-doped diamond skeleton was placed in a mold and served as a sheet-like reinforcement to be compounded with a matrix in parallel arrangement. Afterwards, the mixture was obtained through dripping the bisphenol F epoxy resin precursor solution (a curing agent was diaminodiphenyl (DDM)) into the foamed skeleton at a volume ratio of 1:1, making the paraffin wax fully infiltrated the foamed diamond skeleton, and a mixture was obtained. The mixture was degassed under vacuum for 2 h to remove the bubbles and make the resin precursor solution better impregnate to the pores of the diamond network. Step heating and curing was performed at 100 C. for 2 h, and then raised to 160 C. for 4 h. Finally, after being cooled to room temperature, a bisphenol F epoxy resin matrix composite reinforced with the foamed diamond skeleton was obtained. The thermal conductivity of the composite was 128 W/(m.Math.K).

[0152] According to the thermal conductivity data in the above embodiments, the thermal conductivity of the composite material reinforced with a foamed skeleton prepared by the present invention was greatly improved. The thermal conductivity of the metal matrix composites was up to 976 W/(m.Math.K), and the polymer matrix composites was up to 567 W/(m.Math.K). The thermal conductivity of the paraffin phase change material reinforced with the foamed diamond skeleton, which was up to 79.38 W/(m.Math.K), which was greatly improved compared to paraffin phase change material reinforced with the metal foam. The paraffin phase change material reinforced with the foamed diamond skeleton also has better comprehensive performance than the traditional phase-change energy-storage material. The spatially continuous interpenetrated structure of the foamed skeleton reinforcement and the matrix prepared by the invention can effectively weaken the influence of interface on the thermal properties of materials. It can not only maintain the good plasticity and toughness of the matrix, but also make the reinforcement phase as a whole to maximize the potential of the thermal conductivity, electrical conductivity and excellent mechanical properties of the reinforcement, leading to extremely improved thermal conductivity, electrical conductivity and mechanical strength compared to traditional composite materials and apparently superior comprehensive performance to traditional metal-matrix or polymer-matrix composites. Such a composite possesses much better potential to be utilized as a kind of multifunctional material.

Example 24: Carbon Nanotube/Graphene

[0153] In this example of silicone rubber composite reinforced with a foamed carbon nanotubes/graphene skeleton, a NiFe foam was used as a substrate having a pore diameter of 1 mm. The volume fraction of the foamed graphene reinforcement in the composite was 7%. Firstly, the NiFe foam was cleaned according to step (1). Next, carbon nanotubes were in-situ deposited on the surface of the substrate with no intermediate transition layer by chemical vapor deposition. According to step (4), the carbon nanotubes were catalytically grown on the surface of the graphene by plasma-assisted chemical vapor deposition. Meanwhile, the orientation of the carbon nanotube growth was controlled by the applied electric field, making carbon nanotube form carbon nanotube forests perpendicular to the surface of the graphene. Then a reinforcing layer of carbon nanotubes coated graphene films was obtained. Process parameters are as follows: the mass flow rate of methane was 8%; the deposition temperature was 600 C.; the deposition pressure was 3000 Pa; the plasma current density was 5 mA/cm.sup.2; the magnetic induction intensity was 500 Gs; the deposition time was 30 min. Then the graphene film was deposited by hot-wall CVD, and Specifically, the sample was heated to 950 C. in an atmosphere of H.sub.2 and Ar (flow rate: H.sub.2 was 200 mL/min and Ar was 500 mL/min respectively, heating rate was 33 C./min), and was heat treated for 10 min after the furnace temperature was raised to 950 C. After the heat treatment, the mixture gas of CH.sub.4, H.sub.2 and Ar was introduced (flow rate: CH.sub.4 was 5 mL/min, H.sub.2 was 200 mL/min and Ar was 500 mL/min respectively), and the graphene was grown; cooling rate was 100 C./min; deposition time was 2 h. A three-dimensional network skeleton of graphene coated carbon nanotube on the NiFe foam was obtained. Then, the foamed skeleton of graphene coated carbon nanotube was placed in a mold and served as a bulk reinforcement to be compounded with the matrix. (7) The composite was prepared by impregnation curing: a) Preparation of silicone rubber precursor fluid: weighing 209 silicone rubber precursor, mixing it with a curing agent at a mass ratio of 10:1, and the mixture was mixed with an organic solvent of ethyl acetate at a mass ratio of 1:9, and then stirring vigorously for about 5 min, and the mixture was subjected to vacuum treatment for 5 min to remove bubbles therein. Finally, an ethyl acetate solution of the silicone rubber precursor was obtained. b): Mixing: three-dimensional network skeleton of graphene-coated carbon nanotube was put in a mold. Then the silicone rubber precursor solution was dripped into the graphene/carbon nanotube skeleton at a volume ratio of 2:1, making the solution fully infiltrate into the macroscopic diamond to obtain the mixture. c) Vacuum treatment: the above mixture was degassed under vacuum for 2 h to remove the solvent and bubbles therein and making the silicone rubber precursor solution better impregnate into the pores of the diamond network. d) Heating to 80 C., and insulatingly curing for 4 h, a silicone rubber matrix composite reinforced with graphene foam/carbon nanotube was obtained. The thermal conductivity of the composite was 139 W/(m.Math.K).