A low-cost preparation method for planar high thermal conductivity graphite film reinforced metal matrix composite material

Abstract

A low-cost preparation method for a planar high-thermal-conductivity graphite film reinforced metal-based composite material relates to a preparation method for a metal-based composite material. The purpose is to solve the problems of weak interfacial bonding and low thermal conductivity of the graphite film reinforced metal-based composite material. Method: Graphite film and metal film are taken, TiH2 powder is coated on both surfaces of the graphite film to obtain a titanium-coated graphite film multi-scale reinforcement, which is alternately stacked with the metal film in a graphite mold for pressure infiltration. The present invention uses microwave heating technology to in-situ grow a titanium coating on the surface of the graphite film. The titanium coating overlaps with the reinforcement and the matrix to form a three-dimensional heat conduction path, thereby improving the thermal conductivity of the composite material; the obtained composite material can be used to prepare heat dissipation for heat dissipation systems such as active digital control radars and hypersonic aircraft. The process is simple, low-cost, easy to operate, and can achieve the preparation of large-area high-thermal-conductivity composite materials, meeting the requirements of industrial production and application.

Description

Technical Field

[0001] The invention relates to a method for preparing a metal-based composite material. Background Art

[0002] With the rapid development of aerospace technology and the advent of the 5G era, electronic components are increasingly trending towards miniaturization, lightweighting, and high power density. Thermal management has become a bottleneck restricting the safe, reliable, and high-power operation of these devices. For example, the highly integrated transmit and receive power within a spaceborne phased array antenna, a device with high heat dissipation loads, concentrates heat flux over a large area, creating a serious heat dissipation problem. However, existing aluminum alloy heat dissipation structures no longer meet these requirements. First-generation electronic packaging materials, primarily Invar and Kovar alloys, have thermal expansion coefficients that match those of semiconductors and offer excellent weldability, but their thermal conductivity is too low (<20 W / (m·K)). Second-generation electronic packaging materials, typically W-Cu alloys and Mo-Cu alloys, have lower thermal expansion coefficients and ideal thermal conductivity, but they still struggle to meet the high-intensity heat dissipation requirements of future aircraft designs. Therefore, the development of a new generation of thermal management materials with low thermal expansion coefficients, high thermal conductivity, and lightweight is urgent.

[0003] Synthetic graphite film currently boasts a thermal conductivity of up to 2400 W / (m·K). Its lightweight, high thermal conductivity, corrosion resistance, and antioxidant properties have led to its widespread use in electronic products such as mobile phones, tablet computers, and digital televisions. Traditional graphite film metal-matrix composites suffer from discontinuity between the graphite film reinforcement and the matrix, leading to poor interfacial compatibility. This results in weak interfacial bonding and an inability to form a thermal pathway, leading to reduced interfacial performance and consequently decreased thermal conductivity. Summary of the Invention

[0004] The present invention aims to solve the problems of weak interface bonding and low thermal conductivity of graphite film reinforced metal matrix composite materials, and proposes a low-cost preparation method of planar high thermal conductivity graphite film reinforced metal matrix composite materials.

[0005] The low-cost preparation method of the planar high thermal conductivity graphite film reinforced metal matrix composite material of the present invention is carried out by the following steps:

[0006] 1. Material: Graphite film and metal film, graphite film and metal film have the same shape, thickness and quantity;

[0007] The metal film in step 1 is aluminum foil, copper foil or aluminum alloy film, and the thickness of the metal film is 25 μm to 30 μm;

[0008] 2. Preparation of multi-scale reinforcements of titanium-coated graphite films:

[0009] ①. Soak the graphite film obtained in step 1 in a hot acetone solution, take it out and dry it, then wash it with anhydrous ethanol at room temperature, and then wash it with sodium hydroxide solution and HCl solution in an ultrasonic cleaner in sequence, and then dry it to obtain a pretreated graphite film; there will be impurities such as plasticizers and graphite particles on the surface of the graphite film. Cleaning with acetone can remove these impurities on the surface and open the wrinkles on the graphite film. The heat transfer of the graphite film depends on phonon heat transfer. After the wrinkles are opened, the surface of the graphite film becomes smoother, which can reduce the path of phonon heat transfer;

[0010] ②, TiH2 powder is coated on both surfaces of the graphite film, then placed in a ceramic crucible and transferred to a microwave oven with a protective atmosphere for heating treatment, taken out and cooled to room temperature, and then the obtained graphite film is placed in a constant temperature water bath for heating and cleaning, taken out and placed in an ultrasonic cleaner for cleaning, and finally transferred to a drying oven for drying to obtain a titanium-coated graphite film multi-scale reinforcement;

[0011] The TiH2 powder coating process comprises: firstly dispersing TiH2 powder in Tris buffer until the pH value of the mixed solution is between 8.5 and 9 to obtain a TiH2 dispersion, and then ultrasonically dispersing the dispersion; then applying a layer of dopamine solution to the graphite film by spin coating; and finally applying the prepared TiH2 dispersion to the surface of the graphite film by spin coating to initiate dopamine polymerization, thereby fixing the TiH2 powder on the graphite film;

[0012] Step 2① The mass fraction of the sodium hydroxide solution is 10-15 wt.%; the mass fraction of the HCl solution is 10-20 wt.%;

[0013] Step 2① The mass ratio of the graphite film to the TiH2 powder is 1:0.5-0.8;

[0014] Step 2② The heating temperature is 750-810°C and the time is 0.5-1h;

[0015] 3. Preparation of a metal matrix composite preform: The metal film is cleaned with nitric acid and sodium hydroxide solution in sequence to remove the oxide film on the surface of the metal film. Subsequently, the titanium-coated graphite film multi-scale reinforcement obtained in step 2 and the treated metal film are alternately stacked in a graphite mold, and the titanium-coated graphite film multi-scale reinforcement and the metal film are pressed together to obtain a composite preform;

[0016] 4. Preparation of preheated and molten liquid metal matrix: placing the composite material preform obtained in step 3 with the mold in a heating furnace for preheating to obtain a preheated composite material preform; weighing the metal matrix, heating and melting it under protective gas protection to obtain a molten liquid metal matrix;

[0017] Step 4: The preheating temperature of the composite material preform is 50°C to 200°C below the melting point of the metal matrix, and the holding time is 0.5h to 2h;

[0018] The metal substrate in step 4 is pure aluminum, pure copper or aluminum alloy;

[0019] The heating temperature of the metal substrate in step 4 is 250° C. to 400° C. above the melting point of the metal substrate;

[0020] 5. Pressure impregnation:

[0021] The composite material preform obtained in step 4 is placed with a mold on the operating table of a press, and a liquid metal matrix is ​​cast onto the surface of the composite material preform in the mold for pressure infiltration, whereby the liquid metal is infiltrated into the preform by pressure; the pressure infiltration process is as follows: a pressure of 90 MPa to 120 MPa and an infiltration rate of 1 mm / s to 4 mm / s. After the liquid metal is completely infiltrated into the preform, the preform is cooled to room temperature and demolded;

[0022] The cooling rate in step 5 is 10-15°C / min, and the cooling is carried out in nitrogen, helium or argon protective gas.

[0023] The present invention has the following beneficial effects:

[0024] 1. The present invention provides a low-cost preparation method for preparing a planar high-thermal-conductivity graphite film-reinforced metal-based composite material. A titanium coating is in situ grown on the surface of the graphite film through microwave heating technology. The titanium coating overlaps with each other between the reinforcement and the matrix to form a three-dimensional heat conduction path, thereby improving the thermal conductivity of the composite material. The thermal conductivity of the obtained composite material in the XY direction (parallel to the plane of the graphite film) is as high as 875W / (m·K), and the thermal conductivity in the Z direction (perpendicular to the plane of the graphite film) can reach 19W / (m·K).

[0025] 2. This invention simply introduces an in-situ titanium coating onto the surface of the reinforcing graphite film. The process is simple, low-cost, and easy to operate. It also enables the preparation of large-scale, highly thermally conductive composite materials, meeting the requirements for industrial production and application. The resulting graphite film-reinforced metal matrix composite can be used to heat dissipation systems in active digital control radars, hypersonic aircraft, and other applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a metallographic microscope (OM) photograph of the graphite film reinforced metal matrix composite material obtained in Example 1. DETAILED DESCRIPTION

[0027] The technical solution of the present invention is not limited to the specific implementation methods listed below, but also includes any reasonable combination of the specific implementation methods.

[0028] Specific embodiment 1: The low-cost preparation method of the planar high thermal conductivity graphite film reinforced metal matrix composite material of this embodiment is carried out in the following steps:

[0029] 1. Material: Graphite film and metal film, graphite film and metal film have the same shape, thickness and quantity;

[0030] The metal film in step 1 is aluminum foil, copper foil or aluminum alloy film, and the thickness of the metal film is 25 μm to 30 μm;

[0031] 2. Preparation of multi-scale reinforcements of titanium-coated graphite films:

[0032] ①, soaking the graphite film obtained in step 1 in a hot acetone solution, taking it out and drying it, then washing it with anhydrous ethanol at room temperature, and then washing it with sodium hydroxide solution and HCl solution in an ultrasonic cleaning machine in sequence, and then drying it to obtain a pretreated graphite film;

[0033] ②, TiH2 powder is coated on both surfaces of the graphite film, then placed in a ceramic crucible and transferred to a microwave oven with a protective atmosphere for heating treatment, taken out and cooled to room temperature, and then the obtained graphite film is placed in a constant temperature water bath for heating and cleaning, taken out and placed in an ultrasonic cleaner for cleaning, and finally transferred to a drying oven for drying to obtain a titanium-coated graphite film multi-scale reinforcement;

[0034] The TiH2 powder coating process comprises: firstly dispersing TiH2 powder in Tris buffer until the pH value of the mixed solution is between 8.5 and 9 to obtain a TiH2 dispersion, and then ultrasonically dispersing the dispersion; then applying a layer of dopamine solution to the graphite film by spin coating; and finally applying the prepared TiH2 dispersion to the surface of the graphite film by spin coating to initiate dopamine polymerization, thereby fixing the TiH2 powder on the graphite film;

[0035] Step 2① The mass fraction of the sodium hydroxide solution is 10-15 wt.%; the mass fraction of the HCl solution is 10-20 wt.%;

[0036] Step 2① The mass ratio of the graphite film to the TiH2 powder is 1:0.5-0.8;

[0037] Step 2② The heating temperature is 750-810°C and the time is 0.5-1h;

[0038] 3. Preparation of a metal matrix composite preform: The metal film is cleaned with nitric acid and sodium hydroxide solution in sequence to remove the oxide film on the surface of the metal film. Subsequently, the titanium-coated graphite film multi-scale reinforcement obtained in step 2 and the treated metal film are alternately stacked in a graphite mold, and the titanium-coated graphite film multi-scale reinforcement and the metal film are pressed together to obtain a composite preform;

[0039] 4. Preparation of preheated and molten liquid metal matrix: placing the composite material preform obtained in step 3 with the mold in a heating furnace for preheating to obtain a preheated composite material preform; weighing the metal matrix, heating and melting it under protective gas protection to obtain a molten liquid metal matrix;

[0040] Step 4: The preheating temperature of the composite material preform is 50°C to 200°C below the melting point of the metal matrix, and the holding time is 0.5h to 2h;

[0041] The metal substrate in step 4 is pure aluminum, pure copper or aluminum alloy;

[0042] The heating temperature of the metal substrate in step 4 is 250° C. to 400° C. above the melting point of the metal substrate;

[0043] 5. Pressure impregnation:

[0044] The composite material preform obtained in step 4 is placed with a mold on the operating table of a press, and a liquid metal matrix is ​​cast onto the surface of the composite material preform in the mold for pressure infiltration, whereby the liquid metal is infiltrated into the preform by pressure; the pressure infiltration process is as follows: a pressure of 90 MPa to 120 MPa and an infiltration rate of 1 mm / s to 4 mm / s. After the liquid metal is completely infiltrated into the preform, the preform is cooled to room temperature and demolded;

[0045] The cooling rate in step 5 is 10-15°C / min, and the cooling is carried out in nitrogen, helium or argon protective gas.

[0046] 1. This embodiment provides a low-cost preparation method for preparing a planar high-thermal conductivity graphite film reinforced metal matrix composite material. A titanium coating is in situ grown on the surface of the graphite film through microwave heating technology. The titanium coating overlaps with each other between the reinforcement and the matrix to form a three-dimensional heat conduction path, thereby improving the thermal conductivity of the composite material. The thermal conductivity of the obtained composite material in the XY direction (parallel to the plane of the graphite film) is as high as 875W / (m·K), and the thermal conductivity in the Z direction (perpendicular to the plane of the graphite film) can reach 19W / (m·K).

[0047] 2. This embodiment simply introduces an in-situ titanium coating onto the surface of the reinforcing graphite film. The process is simple, low-cost, and easy to operate. It also enables the production of large-scale, highly thermally conductive composite materials, meeting the requirements for industrial production and application. The resulting graphite film-reinforced metal matrix composite can be used to heat dissipation systems in active digital control radars, hypersonic aircraft, and other applications.

[0048] Specific embodiment 2: The difference between this embodiment and specific embodiment 1 is that the thickness of the graphite film in step 1 is 25 μm to 30 μm.

[0049] Specific embodiment three: This embodiment differs from specific embodiment one or two in that: the aluminum alloy film in step one is an Al-Si alloy film.

[0050] Specific embodiment 4: This embodiment differs from any one of specific embodiments 1 to 3 in that: the concentration of the dopamine solution is 1 g / L to 10 g / L; the volume ratio of the TiH2 dispersion to the dopamine solution is 1:(1 to 1.5).

[0051] Specific embodiment 5: This embodiment differs from specific embodiments 1 to 4 in that: the drying process in step 2① is: drying in a constant temperature drying oven at 60 to 80° C. for 12 to 18 hours.

[0052] Specific embodiment 6: This embodiment differs from specific embodiments 1 to 5 in that the drying process described in step 2② is: drying in a blast drying oven at 60 to 80°C for 18 to 24 hours.

[0053] Specific embodiment seven: This embodiment differs from any one of specific embodiments one to six in that the concentration of nitric acid in step three is 10-15 wt.%.

[0054] Specific embodiment eight: This embodiment differs from any one of specific embodiments one to seven in that the concentration of the sodium hydroxide solution in step three is 0.2 to 0.5 mol / L.

[0055] Specific embodiment 9: This embodiment differs from any one of specific embodiments 1 to 8 in that: the material of the graphite mold in step 3 is high-purity graphite with a purity of 95% to 99%.

[0056] Specific embodiment ten: This embodiment differs from any one of specific embodiments one to nine in that: the protective gas in step four is nitrogen, helium or argon.

[0057] Example 1:

[0058] The low-cost preparation method of the planar high thermal conductivity graphite film reinforced metal matrix composite material of this embodiment is carried out by the following steps:

[0059] 1. Material: Graphite film and metal film, graphite film and metal film have the same shape, thickness and quantity;

[0060] The graphite film thickness in step 1 is 25 μm;

[0061] The metal film in step 1 is aluminum foil, and the thickness of the metal film is 25 μm;

[0062] 2. Preparation of multi-scale reinforcements of titanium-coated graphite films:

[0063] ①, soaking the graphite film obtained in step 1 in a hot acetone solution, taking it out and drying it, then washing it with anhydrous ethanol at room temperature, and then washing it with sodium hydroxide solution and HCl solution in an ultrasonic cleaning machine in sequence, and then drying it to obtain a pretreated graphite film;

[0064] ②, TiH2 powder is coated on both surfaces of the graphite film, then placed in a ceramic crucible and transferred to a microwave oven with a protective atmosphere for heating treatment, taken out and cooled to room temperature, and then the obtained graphite film is placed in a constant temperature water bath for heating and cleaning, taken out and placed in an ultrasonic cleaner for cleaning, and finally transferred to a drying oven for drying to obtain a titanium-coated graphite film multi-scale reinforcement;

[0065] The coating process of the TiH2 powder is as follows: first, the TiH2 powder is dispersed in a Tris buffer solution until the pH value of the mixed solution reaches 8.5 to obtain a TiH2 dispersion, and then ultrasonically dispersed; then, a layer of dopamine solution is applied to the graphite film by spin coating; finally, the prepared TiH2 dispersion is applied to the surface of the graphite film by spin coating again to initiate dopamine polymerization and fix the TiH2 powder on the graphite film; the concentration of the dopamine solution is 5 g / L; and the volume ratio of the TiH2 dispersion to the dopamine solution is 1:1.

[0066] Step 2① The mass fraction of the sodium hydroxide solution is 10 wt.%; the mass fraction of the HCl solution is 10 wt.%;

[0067] Step 2① The mass ratio of the graphite film to the TiH2 powder is 1:0.5;

[0068] Step 2① The drying process is: drying in a constant temperature drying oven at 60°C for 12 hours;

[0069] Step 2② The heating temperature is 810°C and the time is 0.5h;

[0070] The drying process in step 2② is as follows: drying in a forced air drying oven at 80°C for 24 hours;

[0071] 3. Preparation of a metal matrix composite preform: The metal film is cleaned with nitric acid and sodium hydroxide solution in sequence to remove the oxide film on the surface of the metal film. Subsequently, the titanium-coated graphite film multi-scale reinforcement obtained in step 2 and the treated metal film are alternately stacked in a graphite mold, and the titanium-coated graphite film multi-scale reinforcement and the metal film are pressed together to obtain a composite preform;

[0072] The concentration of nitric acid in step 3 is 10 wt.%;

[0073] The concentration of the sodium hydroxide solution in step 3 is 0.4 mol / L;

[0074] The graphite mold in step 3 is made of high-purity graphite with a purity of 99%;

[0075] 4. Preparation of preheated and molten liquid metal matrix: placing the composite material preform obtained in step 3 with the mold in a heating furnace for preheating to obtain a preheated composite material preform; weighing the metal matrix, heating and melting it under protective gas protection to obtain a molten liquid metal matrix;

[0076] The preheating temperature of the composite material preform in step 4 is 550° C. and the holding time is 1 hour;

[0077] The metal substrate in step 4 is pure aluminum;

[0078] The protective gas in step 4 is nitrogen;

[0079] The heating temperature of the metal substrate in step 4 is 960°C;

[0080] 5. Pressure impregnation:

[0081] The composite material preform obtained in step 4 is placed with the mold on the operating table of the press, and the liquid metal matrix is ​​cast onto the surface of the composite material preform in the mold for pressure infiltration, whereby the liquid metal is infiltrated into the preform by pressure; the pressure infiltration process is as follows: the pressure is 90 MPa, the infiltration rate is 2 mm / s, and after the liquid metal is completely infiltrated into the preform, the preform is cooled to room temperature and demolded;

[0082] The cooling rate in step 5 is 10° C. / min, and the cooling is carried out in an argon protective gas.

[0083] Figure 1 This is a metallographic micrograph (OM) of the graphite film reinforced metal matrix composite material obtained in Example 1. As shown in Figure 1, the composite material has a strong interface bond, and no obvious interface debonding or pores are observed. The density of the composite material is 2.64 g / m 3 The interlaminar shear strength is 109 MPa, the thermal conductivity in the XY direction is 875 W / (m·K), and the thermal conductivity in the Z direction is 19 W / (m·K).

[0084] Example 2:

[0085] The low-cost preparation method of the planar high thermal conductivity graphite film reinforced metal matrix composite material of this embodiment is carried out by the following steps:

[0086] 1. Material: Graphite film and metal film, graphite film and metal film have the same shape, thickness and quantity;

[0087] The graphite film thickness in step 1 is 30 μm;

[0088] The metal film in step 1 is aluminum foil (pure aluminum), and the thickness of the metal film is 30 μm;

[0089] 2. Preparation of multi-scale reinforcements of titanium-coated graphite films:

[0090] ①, soaking the graphite film obtained in step 1 in a hot acetone solution, taking it out and drying it, then washing it with anhydrous ethanol at room temperature, and then washing it with sodium hydroxide solution and HCl solution in an ultrasonic cleaning machine in sequence, and then drying it to obtain a pretreated graphite film;

[0091] ②, TiH2 powder is coated on both surfaces of the graphite film, then placed in a ceramic crucible and transferred to a microwave oven with a protective atmosphere for heating treatment, taken out and cooled to room temperature, and then the obtained graphite film is placed in a constant temperature water bath for heating and cleaning, taken out and placed in an ultrasonic cleaner for cleaning, and finally transferred to a drying oven for drying to obtain a titanium-coated graphite film multi-scale reinforcement;

[0092] The coating process of the TiH2 powder is as follows: first, the TiH2 powder is dispersed in a Tris buffer solution until the pH value of the mixed solution reaches 8.5 to obtain a TiH2 dispersion, and then ultrasonically dispersed; then, a layer of dopamine solution is applied to the graphite film by spin coating; finally, the prepared TiH2 dispersion is applied to the surface of the graphite film by spin coating again to initiate dopamine polymerization and fix the TiH2 powder on the graphite film; the concentration of the dopamine solution is 5 g / L; and the volume ratio of the TiH2 dispersion to the dopamine solution is 1:1.

[0093] Step 2① The mass fraction of the sodium hydroxide solution is 10 wt.%; the mass fraction of the HCl solution is 10 wt.%;

[0094] Step 2① The mass ratio of the graphite film to the TiH2 powder is 1:0.5;

[0095] Step 2① The drying process is: drying in a constant temperature drying oven at 60°C for 12 hours;

[0096] Step 2② The heating temperature is 810°C and the time is 0.5h;

[0097] The drying process in step 2② is as follows: drying in a forced air drying oven at 80°C for 24 hours;

[0098] 3. Preparation of a metal matrix composite preform: The metal film is cleaned with nitric acid and sodium hydroxide solution in sequence to remove the oxide film on the surface of the metal film. Subsequently, the titanium-coated graphite film multi-scale reinforcement obtained in step 2 and the treated metal film are alternately stacked in a graphite mold, and the titanium-coated graphite film multi-scale reinforcement and the metal film are pressed together to obtain a composite preform;

[0099] The concentration of nitric acid in step 3 is 10 wt.%;

[0100] The concentration of the sodium hydroxide solution in step 3 is 0.4 mol / L;

[0101] The graphite mold in step 3 is made of high-purity graphite with a purity of 99%;

[0102] 4. Preparation of preheated and molten liquid metal matrix: placing the composite material preform obtained in step 3 with the mold in a heating furnace for preheating to obtain a preheated composite material preform; weighing the metal matrix, heating and melting it under protective gas protection to obtain a molten liquid metal matrix;

[0103] The preheating temperature of the composite material preform in step 4 is 550° C. and the holding time is 1 hour;

[0104] The metal substrate in step 4 is pure aluminum;

[0105] The protective gas in step 4 is argon;

[0106] The heating temperature of the metal substrate in step 4 is 960°C;

[0107] 5. Pressure impregnation:

[0108] The composite material preform obtained in step 4 is placed with the mold on the operating table of the press, and the liquid metal matrix is ​​cast onto the surface of the composite material preform in the mold for pressure infiltration, whereby the liquid metal is infiltrated into the preform by pressure; the pressure infiltration process is as follows: the pressure is 90 MPa, the infiltration rate is 2 mm / s, and after the liquid metal is completely infiltrated into the preform, the preform is cooled to room temperature and demolded;

[0109] The cooling rate in step 5 is 15° C. / min, and the cooling is performed in a helium protective gas.

[0110] After testing, the density of the composite material was 2.65g / m 3 , the interlaminar shear strength is 115MPa, the thermal conductivity in the XY direction is 683W / (m·K), and the thermal conductivity in the Z direction is 15W / (m·K).

[0111] Example 3:

[0112] The low-cost preparation method of the planar high thermal conductivity graphite film reinforced metal matrix composite material of this embodiment is carried out by the following steps:

[0113] 1. Material: Graphite film and metal film, graphite film and metal film have the same shape, thickness and quantity;

[0114] The graphite film thickness in step 1 is 25 μm;

[0115] The metal film in step 1 is aluminum foil (pure aluminum), and the thickness of the metal film is 25 μm;

[0116] 2. Preparation of multi-scale reinforcements of titanium-coated graphite films:

[0117] ①, soaking the graphite film obtained in step 1 in a hot acetone solution, taking it out and drying it, then washing it with anhydrous ethanol at room temperature, and then washing it with sodium hydroxide solution and HCl solution in an ultrasonic cleaning machine in sequence, and then drying it to obtain a pretreated graphite film;

[0118] ②, TiH2 powder is coated on both surfaces of the graphite film, then placed in a ceramic crucible and transferred to a microwave oven with a protective atmosphere for heating treatment, taken out and cooled to room temperature, and then the obtained graphite film is placed in a constant temperature water bath for heating and cleaning, taken out and placed in an ultrasonic cleaner for cleaning, and finally transferred to a drying oven for drying to obtain a titanium-coated graphite film multi-scale reinforcement;

[0119] The coating process of the TiH2 powder is as follows: first, the TiH2 powder is dispersed in a Tris buffer solution until the pH value of the mixed solution reaches 8.5 to obtain a TiH2 dispersion, and then ultrasonically dispersed; then, a layer of dopamine solution is applied to the graphite film by spin coating; finally, the prepared TiH2 dispersion is applied to the surface of the graphite film by spin coating again to initiate dopamine polymerization and fix the TiH2 powder on the graphite film; the concentration of the dopamine solution is 5 g / L; and the volume ratio of the TiH2 dispersion to the dopamine solution is 1:1.

[0120] Step 2① The mass fraction of the sodium hydroxide solution is 10 wt.%; the mass fraction of the HCl solution is 10 wt.%;

[0121] Step 2① The mass ratio of the graphite film to the TiH2 powder is 1:0.5;

[0122] Step 2① The drying process is: drying in a constant temperature drying oven at 60°C for 12 hours;

[0123] Step 2② The heating temperature is 810°C and the time is 0.5h;

[0124] The drying process in step 2② is as follows: drying in a forced air drying oven at 80°C for 24 hours;

[0125] 3. Preparation of a metal matrix composite preform: The metal film is cleaned with nitric acid and sodium hydroxide solution in sequence to remove the oxide film on the surface of the metal film. Subsequently, the titanium-coated graphite film multi-scale reinforcement obtained in step 2 and the treated metal film are alternately stacked in a graphite mold, and the titanium-coated graphite film multi-scale reinforcement and the metal film are pressed together to obtain a composite preform;

[0126] The concentration of nitric acid in step 3 is 10 wt.%;

[0127] The concentration of the sodium hydroxide solution in step 3 is 0.4 mol / L;

[0128] The graphite mold in step 3 is made of high-purity graphite with a purity of 99%;

[0129] 4. Preparation of preheated and molten liquid metal matrix: placing the composite material preform obtained in step 3 with the mold in a heating furnace for preheating to obtain a preheated composite material preform; weighing the metal matrix, heating and melting it under protective gas protection to obtain a molten liquid metal matrix;

[0130] The preheating temperature of the composite material preform in step 4 is 834° C. and the holding time is 1 hour;

[0131] The metal substrate in step 4 is pure copper;

[0132] The protective gas in step 4 is argon;

[0133] The heating temperature of the metal substrate in step 4 is 1184°C;

[0134] 5. Pressure impregnation:

[0135] The composite material preform obtained in step 4 is placed with the mold on the operating table of the press, and the liquid metal matrix is ​​cast onto the surface of the composite material preform in the mold for pressure infiltration, whereby the liquid metal is infiltrated into the preform by pressure; the pressure infiltration process is as follows: the pressure is 90 MPa, the infiltration rate is 2 mm / s, and after the liquid metal is completely infiltrated into the preform, the preform is cooled to room temperature and demolded;

[0136] The cooling rate in step 5 is 10° C. / min, and the cooling is performed in a helium protective gas.

[0137] After testing, the density of the composite material was 2.95g / m 3 , the interlaminar shear strength is 139 MPa, the thermal conductivity in the XY direction is 983 W / (m·K), and the thermal conductivity in the Z direction is 25 W / (m·K).

Claims

1. A low-cost preparation method for a planar high thermal conductivity graphite film reinforced metal matrix composite material, characterized by: The low-cost preparation method of planar high thermal conductivity graphite film reinforced metal matrix composite material is carried out as follows:

1. Material: Graphite film and metal film, graphite film and metal film have the same shape, thickness and quantity; The metal film in step 1 is aluminum foil, copper foil or aluminum alloy film, and the thickness of the metal film is 25 μm to 30 μm; 2. Preparation of multi-scale reinforcements of titanium-coated graphite films: ①, soaking the graphite film obtained in step 1 in a hot acetone solution, taking it out and drying it, then washing it with anhydrous ethanol at room temperature, and then washing it with sodium hydroxide solution and HCl solution in an ultrasonic cleaning machine in sequence, and then drying it to obtain a pretreated graphite film; ②, TiH2 powder is coated on both surfaces of the graphite film, then placed in a ceramic crucible and transferred to a microwave oven with a protective atmosphere for heating treatment, taken out and cooled to room temperature, and then the obtained graphite film is placed in a constant temperature water bath for heating and cleaning, taken out and placed in an ultrasonic cleaner for cleaning, and finally transferred to a drying oven for drying to obtain a titanium-coated graphite film multi-scale reinforcement; The coating process of the TiH2 powder is as follows: firstly, the TiH2 powder is dispersed in a Tris buffer solution until the pH value of the mixed solution is between 8.5 and 9 to obtain a TiH2 dispersion solution, and then ultrasonically dispersed; Then, a layer of dopamine solution is applied to the graphite film by spin coating, and finally, the prepared TiH2 dispersion is applied to the surface of the graphite film by spin coating to initiate dopamine polymerization and fix the TiH2 powder on the graphite film. Step 2① The mass fraction of the sodium hydroxide solution is 10-15 wt.%; the mass fraction of the HCl solution is 10-20 wt.%; Step 2① The mass ratio of the graphite film to the TiH2 powder is 1:0.5-0.8; Step 2② The heating temperature is 750-810°C and the time is 0.5-1h; 3. Preparation of a metal matrix composite preform: The metal film is cleaned with nitric acid and sodium hydroxide solution in sequence to remove the oxide film on the surface of the metal film. Subsequently, the titanium-coated graphite film multi-scale reinforcement obtained in step 2 and the treated metal film are alternately stacked in a graphite mold, and the titanium-coated graphite film multi-scale reinforcement and the metal film are pressed together to obtain a composite preform; 4. Preparation of preheated and molten liquid metal matrix: placing the composite material preform obtained in step 3 with the mold in a heating furnace for preheating to obtain a preheated composite material preform; weighing the metal matrix, heating and melting it under protective gas protection to obtain a molten liquid metal matrix; Step 4: The preheating temperature of the composite material preform is 50°C to 200°C below the melting point of the metal matrix, and the holding time is 0.5h to 2h; The metal substrate in step 4 is pure aluminum, pure copper or aluminum alloy; The heating temperature of the metal substrate in step 4 is 250° C. to 400° C. above the melting point of the metal substrate; 5. Pressure impregnation: The composite material preform obtained in step 4 is placed with a mold on the operating table of a press, and a liquid metal matrix is ​​cast onto the surface of the composite material preform in the mold for pressure infiltration, whereby the liquid metal is infiltrated into the preform by pressure; the pressure infiltration process is as follows: a pressure of 90 MPa to 120 MPa and an infiltration rate of 1 mm / s to 4 mm / s. After the liquid metal is completely infiltrated into the preform, the preform is cooled to room temperature and demolded; The cooling rate in step 5 is 10-15°C / min, and the cooling is carried out in nitrogen, helium or argon protective gas.

2. The low-cost preparation method of a planar high thermal conductivity graphite film reinforced metal matrix composite material according to claim 1, characterized in that: The graphite film thickness in step 1 is 25 μm to 30 μm.

3. The low-cost preparation method of a planar high thermal conductivity graphite film reinforced metal matrix composite material according to claim 1, characterized in that: The aluminum alloy film in step 1 is an Al-Si alloy film.

4. The low-cost preparation method of a planar high thermal conductivity graphite film reinforced metal matrix composite material according to claim 1, characterized in that: The concentration of the dopamine solution is 1 g / L to 10 g / L; the volume ratio of the TiH2 dispersion to the dopamine solution is 1:(1 to 1.5).

5. The low-cost preparation method of a planar high thermal conductivity graphite film reinforced metal matrix composite material according to claim 1, characterized in that: Step 2① The drying process is: drying in a constant temperature drying oven at 60-80°C for 12-18 hours.

6. The low-cost preparation method of a planar high thermal conductivity graphite film reinforced metal matrix composite material according to claim 1, characterized in that: The drying process of step 2② is: drying in a blast drying oven at 60-80°C for 18-24 hours.

7. The low-cost preparation method of a planar high thermal conductivity graphite film reinforced metal matrix composite material according to claim 1, characterized in that: The concentration of the nitric acid in step 3 is 10-15 wt.%.

8. The low-cost preparation method of a planar high thermal conductivity graphite film reinforced metal matrix composite material according to claim 1, characterized in that: The concentration of the sodium hydroxide solution in step 3 is 0.2-0.5 mol / L.

9. The low-cost preparation method of a planar high thermal conductivity graphite film reinforced metal matrix composite material according to claim 1, characterized in that: The graphite mold in step 3 is made of high-purity graphite with a purity of 95% to 99%.

10. The low-cost preparation method of a planar high thermal conductivity graphite film reinforced metal matrix composite material according to claim 1, characterized in that: The protective gas in step 4 is nitrogen, helium or argon.

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