High-thermal-conductivity diamond / silver-copper-based composite material and preparation method thereof

Abstract

The application discloses a high-thermal-conductivity diamond / silver-copper-based composite material and a preparation method thereof, and comprises the following steps: placing diamond blank in a lower chamber of a vacuum air pressure infiltration furnace of a split double-temperature-zone pressure infiltration device, placing a silver-copper alloy in an upper chamber of an induction heating furnace, vacuumizing and heating, pouring the silver-copper alloy into the lower chamber after the silver-copper alloy is melted; quickly removing the upper chamber, screwing in a furnace cover of the lower chamber; introducing inert gas into the lower chamber, and the silver-copper alloy melt infiltrates into the diamond particles under the action of air pressure, and chromium or zirconium in the silver-copper alloy reacts with the diamond to generate carbide with a thickness of 100-200 nm on the surface of the diamond; the silver-copper alloy has low melting point and good fluidity, the diamond is not thermally damaged in the infiltration process, the thickness of the carbide can be accurately controlled, and finally, the composite material with higher density and higher thermal conductivity than the diamond / copper composite material can be obtained. Meanwhile, one upper chamber can be combined with 2-5 lower chambers for step-by-step production, and the equipment efficiency and production capacity are high.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of metal matrix composite material preparation, and particularly relates to a high-thermal-conductivity diamond / silver-copper matrix composite material and a preparation method thereof. BACKGROUND

[0002] With the rapid development of electronic devices towards high performance, miniaturization and high integration, the power density of electronic components is increasing, and the heat generation per unit area is rapidly rising. The heat dissipation problem has become one of the technical bottlenecks restricting the development of the electronic information industry.

[0003] In order to improve the working stability and safety and reliability of electronic components, high-performance thermal management materials have emerged. They can promptly remove the excess heat generated by electronic components, so that the temperature always remains within the normal working range. Thermal management materials usually need to have high thermal conductivity, a thermal expansion coefficient matching the semiconductor device, and light weight and high strength.

[0004] The room temperature thermal conductivity of diamond particles is 1500-2200 W / (m·K), and the room temperature thermal conductivity of copper is 400 W / (m·K). Theoretically, the highest thermal conductivity of diamond / copper composite material is greater than 1000 W / (m·K). However, due to material properties and preparation process problems, the actual thermal conductivity of diamond / copper composite material is only about 700-900 W / (m·K). First, the high temperature instability of diamond. Since the melting point of pure copper is high (1083℃), the preparation temperature of diamond / copper composite material is as high as 1150-1300℃. The high temperature environment will cause thermal damage to diamond, reduce the intrinsic thermal conductivity of diamond, and thus affect the thermal conductivity of the composite material. Second, the poor affinity of diamond particles and copper. The interfacial thermal resistance between them is high, and a thin carbide layer must be formed on the surface of diamond through diamond surface modification method to improve it. However, the high preparation temperature easily leads to the thickness of the carbide layer being too large, which reduces the thermal conductivity of the composite material. In addition, the fluidity of pure copper is poor. Due to the large surface tension of liquid copper, the fluidity of copper is poor at high temperature, which is easy to stick to the mold and cannot be well filled into the diamond pores, so the density of the prepared composite material is low. The pores in the composite material increase the thermal resistance of the composite material and reduce the thermal conductivity of the composite material. In addition to the above problems, the existing preparation method of diamond / copper composite material also has the disadvantages of long time, complex process, high requirement for equipment in high temperature environment, and high production cost.

[0005] The above problems limit the improvement of the thermal conductivity of diamond / copper composite material, and it is also difficult to greatly reduce the preparation cost of diamond / copper. Therefore, it is urgent to find a diamond reinforced metal matrix composite material with low preparation temperature and good matrix fluidity, which can be prepared simply, reduce production cost, and improve production rate. SUMMARY

[0006] In view of the above problems of the prior art, the present application provides a high-thermal-conductivity diamond / silver-copper-based composite material and a preparation method thereof, which is a low-cost and high-efficiency preparation method of the high-thermal-conductivity diamond / silver-copper-based composite material.

[0007] To solve the above technical problems, the present application adopts the following technical solutions:

[0008] The preparation method of the high-thermal-conductivity diamond / silver-copper-based composite material comprises the following steps:

[0009] S1: acid washing, alkali washing and anhydrous ethanol cleaning pretreatment are performed on the diamond particles, and the diamond particles are dried;

[0010] S2: the pretreated diamond particles are filled into a forming mold, and then a vibrating machine is used to vibrate the diamond particles to form a diamond blank;

[0011] S3: the diamond blank obtained in the above step is placed in the lower chamber of a vacuum air pressure infiltration furnace of a split double-temperature-zone pressure infiltration device together with the forming mold, and a silver-copper matrix alloy is placed in a molten metal crucible of the upper chamber of an induction heating furnace of the split double-temperature-zone pressure infiltration device; then the upper chamber of the induction heating furnace and the lower chamber of the vacuum air pressure infiltration furnace are vacuumized, and when the vacuum degree is reduced to 10-10 Pa, heating is performed; after the upper chamber of the induction heating furnace and the lower chamber of the vacuum air pressure infiltration furnace reach the set temperature and are kept constant, the molten silver-copper matrix alloy is poured into the forming mold; the heating of the upper chamber of the induction heating furnace and the vacuumization are stopped, high-purity inert gas is introduced into the lower chamber of the vacuum air pressure infiltration furnace, and the pressure in the furnace is increased to normal pressure and then the gas introduction is stopped; -2

[0012] The silver-copper matrix alloy is a silver-copper-chromium alloy or a silver-copper-zirconium alloy, and the composition of the silver-copper matrix alloy is as follows in terms of mass percentage: Ag: 60-70%, Cr or Zr: 0.5-1.2%, and Cu: the balance;

[0013] The set temperature of the upper chamber of the induction heating furnace is 950-1050℃, and the set temperature of the lower chamber of the vacuum air pressure infiltration furnace is 860-950℃;

[0014] S4: the upper chamber of the induction heating furnace is quickly disassembled and assembled, and the furnace cover of the lower chamber of the vacuum air pressure infiltration furnace is screwed; after high-pressure high-purity inert gas is introduced into the lower chamber of the vacuum air pressure infiltration furnace to a pressure of 5-20 MPa, the silver-copper matrix alloy melt is infiltrated into the pores of the diamond particles under the action of the gas pressure, and at the same time, the chromium or zirconium elements in the silver-copper matrix alloy melt react with the diamond particles to generate a carbonized chromium or carbonized zirconium with a thickness of 100-200 nm on the surface of the diamond particles; after constant temperature and pressure for 5-20 min, the heating power is turned off and the furnace is cooled to below 200℃, and a diamond / silver-copper-based composite material is obtained; ​

[0015] The split type double-temperature zone pressure infiltration device of step S3 comprises a quick detachable and quick mountable induction heating furnace upper chamber, a vacuum air pressure infiltration furnace lower chamber, a vacuum system, an air charging system and an electrical control system; the vacuum air pressure infiltration furnace lower chamber is connected with the vacuum system and the air charging system, and the electrical control system controls the whole split type double-temperature zone pressure infiltration device;

[0016] The induction heating furnace upper chamber is a medium frequency induction furnace, and from outside to inside, the induction heating furnace upper chamber comprises a medium frequency induction furnace shell, an induction coil and a molten metal crucible; the induction heating furnace upper chamber is connected with a medium frequency power source through a cable, and the cable is a quick detachable and quick mountable structure;

[0017] The vacuum air pressure infiltration furnace lower chamber comprises, from outside to inside, a bell jar type heat preservation cylinder, a graphite heating body and an infiltration composite mold; the bottom of the vacuum air pressure infiltration furnace lower chamber is provided with an air charging interface and a vacuum interface;

[0018] The bottom of the induction heating furnace upper chamber and the top of the bell jar type heat preservation cylinder of the vacuum air pressure infiltration furnace lower chamber are both provided with a metal liquid flow hole, and the induction heating furnace upper chamber and the vacuum air pressure infiltration furnace lower chamber are connected through a screw-in type clamping groove cooperation;

[0019] The induction heating furnace upper chamber is combined with 1-5 vacuum air pressure infiltration furnace lower chambers to perform step-by-step production.

[0020] In the present application,

[0021] The particle size of the diamond particles in step S1 is 45-450 mu m; when other conditions are the same, with the increase of the particle size of the diamond particles, the interface thermal resistance between the silver-copper matrix alloy and the diamond particles decreases, the thermal conductivity of the diamond / silver-copper matrix composite material increases, but the bending strength of the composite material also decreases; in combination of the two performance indexes of thermal conductivity and bending strength, the particle size of the diamond particles is preferably 45-450 mu m.

[0022] The silver-copper base alloy in step S3 is a silver-copper-chromium alloy or a silver-copper-zirconium alloy, and the silver-copper base alloy has a composition of Ag: 60-70%, Cr or Zr: 0.5-1.2%, and Cu: the balance in terms of mass percentage, and the alloy has a melting point of 779-820°C. Studies have shown that, above 980°C, the surface of the diamond particles will have obvious craters similar to the surface of the moon, and part of the surface layer will fall off, so that the intrinsic thermal conductivity of the diamond will decrease. In the present application, the Ag-30-40wt.% Cu alloy near the eutectic composition is selected as the base alloy, which has a low melting point and good fluidity, and can be prepared at a temperature of 860-950°C (which is 80-130°C higher than the melting point), so that the problem of thermal damage to the diamond can be effectively avoided, and the high thermal conductivity of the diamond can be ensured, and finally a high-thermal-conductivity composite material is obtained. In addition, because the wettability of the diamond and the silver-copper base alloy is poor, the interface bonding between the two is weak, and the interface thermal resistance is high, which seriously affects the thermal conductivity of the composite material. Therefore, 0.5-1.2% of chromium or zirconium elements are added to the silver-copper base alloy, and during the high-temperature and high-pressure infiltration process, the chromium or zirconium will react with the surface of the diamond particles to form a chromium carbide or zirconium carbide reaction layer, so that the interface bonding between the diamond and the silver-copper base alloy is significantly improved, the interface thermal resistance is reduced, and it is beneficial to obtain a composite material with high thermal conductivity. When the content of chromium or zirconium elements is too low, the generated chromium carbide or zirconium carbide reaction layer is too thin to improve the interface bonding effect; when the content of chromium or zirconium elements is too high, the generated chromium carbide or zirconium carbide reaction layer is too thick, which increases the interface thermal resistance, and at the same time, the thermal conductivity of the silver-copper base alloy will also decrease with the increase of the content of chromium or zirconium elements, so the content of chromium or zirconium is preferably 0.5-1.2% in terms of mass percentage.

[0023] In step S3, the temperature of the upper chamber of the induction heating furnace is set to 950-1050°C, and the temperature of the lower chamber of the vacuum air pressure infiltration furnace is set to 860-950°C. The melting point of the silver-copper base alloy is 779-820°C. The temperature of the upper chamber of the induction heating furnace is set to 950-1050°C to ensure that the silver-copper base alloy is fully melted and has good fluidity, which is beneficial to the infiltration and combination of the silver-copper base alloy melt from top to bottom into the lower chamber of the vacuum air pressure infiltration furnace and the forming mold. The temperature of the lower chamber of the vacuum air pressure infiltration furnace is 860-950°C, which is the infiltration temperature, so as to avoid damaging the original thermal conductivity of the diamond particles.

[0024] In step S3, the heating of the upper chamber of the induction heating furnace adopts induction heating, and the temperature rising rate is 200-300℃ / min. The purpose of induction heating is to rapidly heat and melt the silver-copper matrix alloy, so as to avoid alloy oxidation and improve production efficiency. The heating of the lower chamber of the vacuum air pressure infiltration furnace adopts graphite heating element heating, and the temperature rising rate is 10-20℃ / min. The graphite heating element heating can accurately control the infiltration temperature of the lower chamber of the vacuum air pressure infiltration furnace and control the diffusion reaction rate of diamond and chromium or zirconium in the silver-copper matrix alloy, so as to accurately control the thickness of the chromium carbide or zirconium carbide layer on the surface of the diamond.

[0025] The upper chamber of the induction heating furnace in step S3 is provided with a lifting rod, which passes through the bottom of the molten metal crucible and corresponds to the flow hole from the top of the upper chamber of the induction heating furnace. The cable is made into a quick release and quick connection structure, so that the upper chamber of the induction heating furnace can be quickly removed after the silver-copper matrix alloy melt is poured, and the temperature of the lower chamber of the vacuum air pressure infiltration furnace is prevented from fluctuating greatly and air from entering during the removal process.

[0026] The lower chamber of the vacuum air pressure infiltration furnace in step S3 is provided with a furnace cover, and the lower chamber of the vacuum air pressure infiltration furnace is connected with the furnace cover through a rotating slot. The infiltration composite mold of the lower chamber of the vacuum air pressure infiltration furnace includes a graphite crucible and a forming mold. The graphite heating element and the surface of the graphite crucible are both provided with a thin layer of silicon carbide material obtained by chemical vapor deposition, so as to improve the oxidation resistance of the graphite heating element and the graphite crucible.

[0027] The inner and outer layers of the bell jar type heat preservation cylinder in the lower chamber of the vacuum air pressure infiltration furnace in step S3 are metal sheets, which are connected by riveting or welding process, and the heat preservation material is filled between the two sheets.

[0028] The upper chamber of the induction heating furnace and the lower chamber of the vacuum air pressure infiltration furnace in step S3 are both double-layer water circulation metal shells. The upper chamber of the induction heating furnace and the lower chamber of the vacuum air pressure infiltration furnace are connected through a rotating slot, which can meet the requirements of quick release and quick connection of the upper chamber of the induction heating furnace. At the same time, the sealing requirements of the connection between the upper chamber of the induction heating furnace and the lower chamber of the vacuum air pressure infiltration furnace during vacuumizing and air charging are met.

[0029] In step S3, after the constant temperature is ended, the lifting rod in the molten metal crucible of the upper chamber of the induction heating furnace is lifted, and the silver-copper matrix alloy melt flows into the forming mold of the lower chamber of the vacuum air pressure infiltration furnace through the flow hole.

[0030] The upper chamber 1 of the induction heating furnace in step S3 is combined with the lower chambers 2-5 of the vacuum gas pressure infiltration furnace to perform step production. Specifically, when the upper chamber of the induction heating furnace is combined with the lower chamber of the first vacuum gas pressure infiltration furnace to work, the second to fifth vacuum gas pressure infiltration furnaces are placed with the forming molds containing the diamond blanks, and the heating power is sequentially turned on under the protection of inert gas. After the silver-copper matrix alloy is melted and poured into the forming mold in the lower chamber of the first vacuum gas pressure infiltration furnace, the upper chamber of the induction heating furnace is quickly separated from the lower chamber of the first vacuum gas pressure infiltration furnace, and the first vacuum gas pressure infiltration furnace is further operated in step S4. The cover of the lower chamber of the second vacuum gas pressure infiltration furnace is opened, the upper chamber of the induction heating furnace is screwed in, and the cable of the upper chamber of the induction heating furnace is quickly connected. Then, the cover of the induction heating furnace is opened, the silver-copper matrix alloy is put in, the power is turned on to heat and melt the silver-copper matrix alloy. Next, the vacuum system of the lower chamber of the second vacuum gas pressure infiltration furnace is opened, and vacuum is started. When the upper chamber of the induction heating furnace and the lower chamber of the vacuum gas pressure infiltration furnace reach the program set temperature, the operation is performed according to "lift the lifting rod-silver-copper matrix alloy pouring-close the vacuum system-charge to normal pressure-separate the upper chamber of the induction heating furnace from the lower chamber of the vacuum gas pressure infiltration furnace-the lower chamber of the vacuum gas pressure infiltration furnace is operated in step S4". Then, the upper chamber of the induction heating furnace is sequentially combined with the lower chambers of the third, fourth and fifth vacuum gas pressure infiltration furnaces in turn to perform step production.

[0031] In step S4, the screw-in clamping slots on both sides of the upper chamber of the induction heating furnace and the lower chamber of the vacuum gas pressure infiltration furnace are opened, the upper chamber of the induction heating furnace is quickly removed, the cover of the lower chamber of the vacuum gas pressure infiltration furnace is screwed in, and the lower chamber of the vacuum gas pressure infiltration furnace is sealed. After the high-pressure high-purity inert gas is filled into the lower chamber of the vacuum gas pressure infiltration furnace to 5-20 MPa, the temperature and pressure are kept constant for 5-20 min to complete the compounding between the silver-copper matrix alloy and the diamond. The heating of the lower chamber of the vacuum gas pressure infiltration furnace is stopped, and the furnace is cooled down. When the temperature is below 200℃, the diamond / silver-copper matrix composite material is taken out. The purpose of keeping the temperature and pressure constant for 5-20 min is to make the silver-copper matrix alloy melt infiltrate into the pores of the diamond particles, and to make the chromium or zirconium elements in the silver-copper matrix alloy melt react with the diamond particles to form a 100-200 nm thick chromium carbide or zirconium carbide on the surface of the diamond particles. Since the thermal conductivity of zirconium carbide or chromium carbide is 20-120 W / (m·K), the thermal conductivity is low, so when preparing the diamond reinforced metal matrix composite material, on the basis of complete coverage of chromium carbide or zirconium carbide, the thinner the thickness of the chromium carbide or zirconium carbide layer, the higher the thermal conductivity of the diamond reinforced metal matrix composite material.

[0032] In step S4, the volume fraction of the diamond particle reinforced phase in the diamond / silver-copper matrix composite material is 40-80%.

[0033] The application also relates to a high-thermal-conductivity diamond / silver-copper-based composite material prepared by the method.

[0034] Compared with the prior art, the application has the following advantages:

[0035] 1. The high-thermal-conductivity diamond / silver-copper-based composite material uses a silver-copper matrix alloy as the composite material matrix, and the preparation temperature can be as low as 950 DEG C or below, so that the possibility of high-temperature thermal damage of the diamond is greatly reduced; meanwhile, the low preparation temperature can significantly reduce the reaction rate of the chromium or zirconium element in the silver-copper matrix alloy and the diamond, so that the thickness of the chromium carbide or zirconium carbide reaction layer can be accurately controlled, and the diamond / silver-copper-based composite material with low interface thermal resistance and high thermal conductivity can be obtained; in addition, the fluidity of the silver-copper matrix alloy is better than that of pure copper; the melt fluidity is related to the melt surface tension and viscosity, and the addition of silver in the pure copper can reduce the melt surface tension, reduce the viscosity and improve the melt fluidity. For example, the surface tension of the liquid pure Cu at 1085 DEG C is 1330 mN / m, while the surface tension of the liquid Ag-40% Cu alloy is 940 mN / m, and the surface tension decreases with the increase of the Ag content. The better fluidity of the silver-copper matrix alloy is conducive to the infiltration and compounding of the silver-copper matrix alloy from top to bottom into the gap between the diamond particles, so that the better compactness of the composite material is ensured.

[0036] 2. The preparation method of the high-thermal-conductivity diamond / silver-copper-based composite material uses the induction heating furnace upper chamber of the split-type double-temperature-zone pressure infiltration device to be connected with the vacuum air pressure infiltration furnace lower chamber through the screw-in type clamping groove cooperation, so as to meet the sealing requirement of the upper and lower chamber connection when vacuumizing and aerating; meanwhile, the induction heating furnace upper chamber meets the quick disassembly and quick assembly requirement. After the induction heating furnace upper chamber completes the melting and pouring task of the silver-copper matrix alloy, the induction heating furnace upper chamber is quickly removed, and then the furnace cover of the vacuum air pressure infiltration furnace lower chamber is quickly screwed in, so that the vacuum air pressure infiltration furnace lower chamber is sealed, and the air pressure infiltration task in the vacuum air pressure infiltration furnace lower chamber is completed. Compared with the existing pressure infiltration device, the size of the vacuum air pressure infiltration part of the device is obviously reduced, and the equipment manufacturing, maintenance and operation cost is significantly reduced.

[0037] 3. The preparation method of the high-thermal-conductivity diamond / silver-copper-based composite material, the upper cavity of the split double-temperature-zone pressure infiltration device adopts an induction heating furnace, silver-copper matrix alloy can be melted in the upper cavity for 0.5 hours, and the upper cavity can be quickly disassembled and assembled; the lower cavity of the vacuum air pressure infiltration furnace is usually preheated, infiltrated and cooled for several hours, so that the upper cavity of one induction heating furnace can be combined with the lower cavities of 2-5 vacuum air pressure infiltration furnaces to perform step production, the equipment efficiency and production capacity are high, the actual production line can continuously infiltrate products, and the material manufacturing cost is obviously reduced. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 The structure diagram of the split double-temperature-zone pressure infiltration device for preparing the high-thermal-conductivity metal-based composite material is described in the embodiments of the present application.

[0039] Figure 2 The structure diagram of the split double-temperature-zone pressure infiltration device for preparing the high-thermal-conductivity metal-based composite material after the upper cavity of the induction heating furnace is removed is described in the embodiments of the present application.

[0040] Figure 3 The diamond / silver-copper-based composite material obtained by the preparation method of the high-thermal-conductivity diamond / silver-copper-based composite material described in embodiment 1 is shown in the actual object diagram.

[0041] Figure 4 The 100 times optical photograph of the diamond / silver-copper-based composite material obtained by the preparation method of the high-thermal-conductivity diamond / silver-copper-based composite material described in embodiment 1 is shown in the diagram.

[0042] In the drawings, the following marks are marked:

[0043] 1, upper cavity of induction heating furnace; 2, lower cavity of vacuum air pressure infiltration furnace; 3, shell of intermediate frequency induction furnace; 4, molten metal crucible; 5, induction coil; 6, air charging interface; 7, vacuum interface; 8, graphite heating body; 9, forming mold; 10, bell-shaped heat preservation cylinder; 11, flow-through small hole; 12, furnace cover; 13, graphite crucible; 14, lifting rod. DETAILED DESCRIPTION

[0044] The present application will be further described in detail by the following examples, but these examples should not be considered as limiting the present application.

[0045] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative labor fall within the protection scope of the present application.

[0046] Embodiment 1

[0047] A preparation method of a high-thermal-conductivity diamond / silver-copper-based composite material, comprising the following steps:

[0048] S1: performing acid washing, alkali washing and anhydrous ethanol cleaning pretreatment on diamond particles, and drying;

[0049] S2: filling the pretreated diamond particles into a forming mold, and then vibrating the diamond particles with a vibrating machine to form a diamond blank;

[0050] S3: placing the diamond blank together with the forming mold in a lower chamber of a vacuum-air-pressure-infiltration furnace of a split double-temperature-zone pressure infiltration device, and placing a silver-copper matrix alloy in a graphite crucible in an upper chamber of an induction heating furnace of the split double-temperature-zone pressure infiltration device; then vacuumizing and heating the upper and lower chambers, after the upper and lower chambers respectively reach the set temperature and keep constant, pouring the molten silver-copper matrix alloy into the forming mold; stopping heating and vacuumizing the upper chamber of the induction heating furnace, and then introducing high-purity inert gas to increase the pressure in the furnace to normal pressure and then stopping the gas introduction;

[0051] S4: quickly removing the upper chamber of the induction heating furnace, and screwing the furnace cover of the lower chamber of the vacuum-air-pressure-infiltration furnace; introducing high-pressure high-purity inert gas into the lower chamber of the vacuum-air-pressure-infiltration furnace, and infiltrating the silver-copper matrix alloy melt into the pores of the diamond particles under the action of the gas pressure, while the chromium or zirconium elements in the silver-copper matrix alloy melt react with the diamond particles to generate a 100-200nm carbonized chromium or carbonized zirconium layer on the surface of the diamond particles; after constant temperature and pressure for 5-20min, the heating power is turned off and the furnace is cooled to obtain the diamond / silver-copper-based composite material;

[0052] In Embodiments 1-5, the split double-temperature-zone pressure infiltration device is shown in Figures 1-2 , which comprises a quick-detachable and quick-attachable upper chamber 1 of the induction heating furnace, a lower chamber 2 of the vacuum-air-pressure-infiltration furnace, a vacuum system, a gas charging system and an electrical control system;

[0053] The upper chamber 1 of the induction heating furnace is a medium-frequency induction furnace, and from the outside to the inside, it is sequentially a medium-frequency induction furnace shell 3, a molten metal crucible 4 and an induction coil 5; the upper chamber 1 of the induction heating furnace is connected with a medium-frequency power source through a cable, wherein the cable is a quick-detachable and quick-attachable structure; the lower chamber 2 of the vacuum-air-pressure-infiltration furnace comprises a gas charging interface 6, a vacuum interface 7, a graphite heating body 8, an infiltration composite mold and a bell-shaped heat preservation cylinder 10, etc.;

[0054] The metal liquid flow hole 11 is arranged at the bottom of the upper chamber 1 of the induction heating furnace and the top of the bell-shaped heat preservation cylinder of the lower chamber 2 of the vacuum air pressure infiltration furnace, and the upper chamber 1 of the induction heating furnace and the lower chamber 2 of the vacuum air pressure infiltration furnace are connected through the screw-in clamping groove connection; the screw-in clamping groove connection can meet the quick disassembly and quick assembly requirements of the upper chamber 1 of the induction heating furnace; meanwhile, the sealing requirements of the connection between the upper chamber 1 of the induction heating furnace and the lower chamber 2 of the vacuum air pressure infiltration furnace during vacuumizing and air charging are met; the quick disassembly and quick connection structure of the cable is to enable the upper chamber 1 of the induction heating furnace to be quickly disassembled and moved after the metal matrix is melted and poured, so as to avoid the large fluctuation of the temperature of the lower chamber 2 of the vacuum air pressure infiltration furnace and the entry of oxygen during the disassembly and movement process;

[0055] The lifting rod 14 is arranged in the upper chamber 1 of the induction heating furnace, and the lifting rod 14 passes through the bottom of the molten metal crucible 4 and corresponds to the flow hole 11 from the top of the upper chamber 1 of the induction heating furnace;

[0056] The furnace cover 12 is arranged on the lower chamber 2 of the vacuum air pressure infiltration furnace, and the lower chamber 2 of the vacuum air pressure infiltration furnace and the furnace cover 12 are connected through the screw-in clamping groove connection, which can ensure the sealing of the connection part between the lower chamber 2 of the vacuum air pressure infiltration furnace and the furnace cover 12 during air charging and vacuumizing; the infiltration composite mold of the lower chamber 2 of the vacuum air pressure infiltration furnace comprises a graphite crucible 13 and a forming mold 9, the inner and outer layers of the bell-shaped heat preservation cylinder 10 are metal sheets, the metal sheets are connected through riveting or welding process, and the heat preservation material is filled between the two sheets, and the upper chamber 1 of the induction heating furnace and the lower chamber 2 of the vacuum air pressure infiltration furnace are both double-layer water circulation metal shells;

[0057] The specific operation of S3 is as follows: first, the pretreated diamond particles are put into the forming mold 9, and then are put into the graphite crucible 13 of the lower chamber of the vacuum air pressure infiltration furnace of the split double-temperature-zone pressure infiltration device, and the silver-copper matrix alloy is placed in the molten metal crucible 4 of the upper chamber 1 of the induction heating furnace of the split double-temperature-zone pressure infiltration device; second, the vacuum system is used to simultaneously vacuumize the upper chamber 1 and the lower chamber 2 through the vacuum interface 7, and when the vacuum degree of the upper and lower chambers is reduced to 10-10 -2 Pa, the heating device is started to make the upper and lower chambers reach the respective set temperatures for constant temperature; after the constant temperature is ended, the lifting rod 14 in the molten metal crucible of the upper chamber of the induction heating furnace is lifted, the silver-copper matrix alloy liquid flows into the forming mold 13 of the lower chamber 2 of the vacuum air pressure infiltration furnace through the flow hole 11, then the heating of the upper chamber of the induction heating furnace is stopped, and the vacuumizing is also stopped, the high-purity inert gas is filled into the air charging interface 6 of the lower chamber of the vacuum air pressure infiltration furnace, and the air charging is stopped after the upper and lower chambers reach the normal pressure;

[0058] The specific operation of S4 is: quickly remove the upper chamber 1 of the induction heating furnace, screw the furnace cover 12 of the lower chamber of the vacuum gas pressure infiltration furnace; high pressure high purity inert gas is introduced into the lower chamber of the vacuum gas pressure infiltration furnace from the gas inlet 6 to 5-20 MPa, and the substrate silver copper liquid is infiltrated into the diamond particle pores under the action of gas pressure, while the chromium or zirconium element in the silver copper substrate reacts with the diamond particles to generate 100-200 nm of chromium carbide or zirconium carbide on the surface of the diamond particles, and after constant temperature and pressure for 5-20 min, the heating power is turned off and the furnace is cooled to obtain a diamond / silver copper matrix composite material.

[0059] Example 2:

[0060] A preparation method of a high-thermal-conductivity diamond / silver copper matrix composite material, comprising the following steps:

[0061] S1: 5 kg of diamond single crystal particles with a particle size of 200 μm are weighed, pretreated by acid washing, alkali washing, and anhydrous ethanol cleaning, and dried;

[0062] S2: the pretreated diamond particles are filled in a forming mold and vibrated by a vibrating machine to form a diamond blank;

[0063] S3: the forming mold containing the diamond particles is placed in a graphite crucible in the lower chamber of the vacuum gas pressure infiltration furnace of the split double-temperature-zone pressure infiltration device, and 10 kg of 70Ag-29.2Cu-0.8Cr alloy is placed in the molten metal crucible in the upper chamber of the induction heating furnace of the split double-temperature-zone pressure infiltration device; first, the vacuum pump on one side of the lower chamber of the vacuum gas pressure infiltration furnace is used to simultaneously vacuumize the upper chamber of the induction heating furnace and the lower chamber of the vacuum gas pressure infiltration furnace, when the vacuum degree in the chamber is reduced to 10 Pa, the heating device is started to make the temperature of the upper chamber of the induction heating furnace be 950℃ and the temperature of the lower chamber of the vacuum gas pressure infiltration furnace be 890℃, after the 70Ag-29.2Cu-0.8Cr alloy in the upper chamber of the induction heating furnace is melted, the lifting rod in the molten metal crucible of the upper chamber of the induction heating furnace is lifted to make the 70Ag-29.2Cu-0.8Cr alloy melt in the upper chamber of the induction heating furnace flow into the forming mold in the lower chamber of the vacuum gas pressure infiltration furnace through the small hole by itself; then, the heating of the upper chamber of the induction heating furnace is stopped, and the vacuumization is stopped, high-purity inert gas is filled into the lower chamber of the vacuum gas pressure infiltration furnace, and the filling is stopped after the upper and lower chambers reach normal pressure;

[0064] S4: open the screw slot on both sides of the upper chamber of the induction heating furnace and the lower chamber of the vacuum gas pressure infiltration furnace, quickly remove the upper chamber of the induction heating furnace, screw the cover of the lower chamber of the vacuum gas pressure infiltration furnace, and seal the lower chamber of the vacuum gas pressure infiltration furnace; after the lower chamber of the vacuum gas pressure infiltration furnace is filled with high-pressure high-purity inert gas to 5 MPa, it is kept constant temperature and pressure for 15 min, and the compounding between the silver-copper matrix alloy and the diamond is completed; stop heating the lower chamber of the vacuum gas pressure infiltration furnace, and cool down with the furnace; when the temperature is below 200°C, take out the diamond / silver-copper matrix composite material;

[0065] Figure 3 The actual picture of the high-thermal-conductivity diamond / silver-copper matrix composite material prepared in this example has a size of 20x20x3mm, a size accuracy of ±0.1mm, and a surface roughness Ra of 0.8μm. As can be seen from the picture, the surface of the composite material is flat, complete, and has no obvious defects, indicating that the process parameters in this example are reasonable, and the silver-copper matrix alloy achieves excellent infiltration effect.

[0066] Figure 4 The 100x optical photo of the high-thermal-conductivity diamond / silver-copper matrix composite material prepared in this example shows that the diamond particles are uniformly distributed in the silver-copper matrix alloy, the interface is well combined, and the structure is dense.

[0067] It is measured that the volume fraction of diamond in the high-thermal-conductivity diamond / silver-copper matrix composite material obtained in this example is 65%, the thickness of the chromium carbide layer on the surface of the diamond particles is 150nm, the density of the composite material is 99.2%, and the thermal conductivity is 816W / (m·K).

[0068] Example 3:

[0069] A method for preparing a high-thermal-conductivity diamond / silver-copper matrix composite material, comprising the following steps:

[0070] S1: weigh 2.5kg of diamond single crystal particles with a particle size of 45μm and 3.5kg of diamond single crystal particles with a particle size of 450μm, and perform acid washing, alkali washing, and anhydrous ethanol cleaning pretreatment, and then dry them;

[0071] S2: fill the pretreated diamond particles in a forming mold, and vibrate the mold with a vibrating machine to form a diamond blank;

[0072] S3: place the forming mold containing the diamond particles in a graphite crucible in the lower chamber of the vacuum gas pressure infiltration furnace of the split double-temperature-zone pressure infiltration device, and place 8.9kg of 70Ag-29.3Cu-0.5Zr alloy in the molten metal crucible in the upper chamber of the induction heating furnace of the split double-temperature-zone pressure infiltration device; first, simultaneously vacuumize the upper chamber of the induction heating furnace and the lower chamber of the vacuum gas pressure infiltration furnace through the vacuum pump on one side of the lower chamber of the vacuum gas pressure infiltration furnace, and when the vacuum degree in the chamber is reduced to 10-1 After the Pa, start heating device to make the induction heating furnace upper chamber temperature is 980℃, vacuum air pressure infiltration furnace lower chamber temperature is 860℃, after the 70Ag-29.3Cu-0.5Zr alloy in the induction heating furnace upper chamber is melted, lift the lifting rod in the induction heating furnace upper chamber molten metal crucible, make the 70Ag-29.3Cu-0.5Zr alloy melt in the induction heating furnace upper chamber flow from top to bottom into the forming mold in the vacuum air pressure infiltration furnace lower chamber;Subsequently stop the induction heating furnace upper chamber heating, stop vacuumizing again, fill high-purity inert gas into the vacuum air pressure infiltration furnace lower chamber, stop filling gas after the upper and lower chambers reach normal pressure;

[0073] S4: open the induction heating furnace upper chamber and vacuum air pressure infiltration furnace lower chamber both sides of the screw-in type clamping groove, quickly remove the induction heating furnace upper chamber, screw into the vacuum air pressure infiltration furnace lower chamber furnace cover, seal the vacuum air pressure infiltration furnace lower chamber;After the vacuum air pressure infiltration furnace lower chamber is filled with high-pressure high-purity inert gas to 20MPa, keep constant temperature and constant pressure for 5min, complete the composite between silver copper matrix alloy and diamond;Stop heating the vacuum air pressure infiltration furnace lower chamber, cool down with the furnace, take out the diamond / silver copper matrix composite material when it is cooled to below 200℃;

[0074] It is measured that the volume fraction of diamond in the high-thermal-conductivity diamond / silver copper matrix composite material obtained in the embodiment is 80%, the thickness of the carbonized zirconium layer on the surface of the diamond particles is 100nm, the density of the composite material is 99.5%, and the thermal conductivity is 1152W / (m·K).

[0075] Example 4:

[0076] A preparation method of a high-thermal-conductivity diamond / silver copper matrix composite material, comprising the following steps:

[0077] S1: weigh 4kg of diamond single crystal particles with a particle size of 100μm, perform acid washing, alkali washing, and anhydrous ethanol cleaning pretreatment, and dry them;

[0078] S2: mix and fill the pretreated diamond particles and 2kg of pure copper powder with a particle size of 100μm in a forming mold, and vibrate the forming mold with a vibrating machine to form a diamond blank;

[0079] S3: place the forming mold containing the diamond particles into a graphite crucible in the vacuum air pressure infiltration furnace lower chamber of a split double-temperature-zone pressure infiltration device, and place 8kg of 60Ag-38.8Cu-1.2Cr alloy into a molten metal crucible in the induction heating furnace upper chamber of the split double-temperature-zone pressure infiltration device;First, simultaneously vacuumize the induction heating furnace upper chamber and the vacuum air pressure infiltration furnace lower chamber through the vacuum pump on one side of the vacuum air pressure infiltration furnace lower chamber, and when the vacuum degree in the chamber is reduced to 5×10 -1After the Pa, start heating device to make the induction heating furnace upper chamber temperature 1050℃, vacuum air pressure infiltration furnace lower chamber temperature 950℃, after the induction heating furnace upper chamber 60Ag-38.8Cu-1.2Cr alloy melting, lift the induction heating furnace upper chamber molten metal crucible in the lifting rod, make the induction heating furnace upper chamber 60Ag-38.8Cu-1.2Cr alloy melt flow through the small hole into the vacuum air pressure infiltration furnace lower chamber forming mold; Then stop the induction heating furnace upper chamber heating, stop vacuumizing again, fill high-purity inert gas from the vacuum air pressure infiltration furnace lower chamber, stop filling gas after the upper and lower chambers to normal pressure;

[0080] S4: open the induction heating furnace upper chamber and vacuum air pressure infiltration furnace lower chamber both sides of the screw-in type clamping groove, quickly remove the induction heating furnace upper chamber, screw into the vacuum air pressure infiltration furnace lower chamber furnace cover, seal the vacuum air pressure infiltration furnace lower chamber; After the vacuum air pressure infiltration furnace lower chamber is filled with high-pressure high-purity inert gas to 10MPa, keep constant temperature and constant pressure for 20min, complete the composite between silver copper matrix alloy and diamond; Stop heating the vacuum air pressure infiltration furnace lower chamber, cool down with the furnace, and take out the diamond / silver copper matrix composite material when the temperature is below 200℃;

[0081] It is measured that the volume fraction of diamond in the high-thermal-conductivity diamond / silver copper matrix composite material obtained in the embodiment is 40%, the thickness of the chromium carbide layer on the surface of the diamond particles is 200nm, the density of the composite material is 99.3%, and the thermal conductivity is 720W / (m·K).

[0082] Example 5:

[0083] A preparation method of a high-thermal-conductivity diamond / silver copper matrix composite material, comprising the following steps:

[0084] S1: weigh 3.2kg of diamond single crystal particles with a particle size of 200μm, perform acid washing, alkali washing, and anhydrous ethanol cleaning pretreatment, and dry;

[0085] S2: mix and fill the pretreated diamond particles and 1.8kg of pure copper powder with a particle size of 100μm in a forming mold, and vibrate the forming mold with a vibrating machine to form a diamond blank;

[0086] S3: place the forming mold containing the diamond particles into a graphite mold in the vacuum air pressure infiltration furnace lower chamber of a split double-temperature-zone pressure infiltration device, and place 7kg of 65Ag-34Cu-1Zr alloy into a molten metal crucible in the induction heating furnace upper chamber of the split double-temperature-zone pressure infiltration device; first, simultaneously vacuumize the induction heating furnace upper chamber and the vacuum air pressure infiltration furnace lower chamber through the vacuum pump on one side of the vacuum air pressure infiltration furnace lower chamber, and when the vacuum degree in the chamber is reduced to 2×10 -1After Pa, the heating device is started to make the temperature of the upper chamber of the induction heating furnace 990 DEG C, the temperature of the lower chamber of the vacuum gas pressure infiltration furnace 910 DEG C, after the 65Ag-34Cu-1Zr alloy in the upper chamber of the induction heating furnace is melted, the lifting rod in the crucible of the upper chamber of the induction heating furnace is lifted, the 65Ag-34Cu-1Zr alloy melt in the upper chamber of the induction heating furnace flows into the forming mold in the lower chamber of the vacuum gas pressure infiltration furnace through the small hole by itself, then the heating of the upper chamber of the induction heating furnace is stopped, the vacuum is stopped, the high-purity inert gas is filled into the lower chamber of the vacuum gas pressure infiltration furnace, and the filling of the gas is stopped after the upper and lower chambers reach the normal pressure;

[0087] S4: the screw-in clamping slots on both sides of the upper chamber of the induction heating furnace and the lower chamber of the vacuum gas pressure infiltration furnace are opened, the upper chamber of the induction heating furnace is quickly removed, the furnace cover of the lower chamber of the vacuum gas pressure infiltration furnace is screwed in, and the lower chamber of the vacuum gas pressure infiltration furnace is sealed; after the high-pressure high-purity inert gas is filled into the lower chamber of the vacuum gas pressure infiltration furnace to 15 MPa, the temperature and pressure are kept constant for 20 min, the compounding between the silver-copper matrix and the diamond is completed; the heating of the lower chamber of the vacuum gas pressure infiltration furnace is stopped, the furnace is cooled, and the diamond / silver-copper matrix composite material is taken out when the temperature is below 200 DEG C;

[0088] It is found that the volume fraction of diamond in the diamond / silver-copper matrix composite material obtained in the embodiment is 55%, the thickness of the carbonized zirconium layer on the surface of the diamond particles is 175 nm, the density of the composite material is 99.1%, and the thermal conductivity is 790 W / (m·K).

[0089] Example 6:

[0090] A preparation method of a high-thermal-conductivity diamond / silver-copper matrix composite material, comprising the following steps:

[0091] S1: 1.5 kg of diamond single crystal particles with a particle size of 50 μm and 1.6 kg of diamond single crystal particles with a particle size of 350 μm are weighed and uniformly mixed, acid washing, alkali washing, anhydrous ethanol cleaning pretreatment are carried out, and drying is carried out;

[0092] S2: the pretreated diamond particles are evenly filled in two forming molds, and a vibrating machine is used for vibration;

[0093] S3: Put two shaped molds containing diamond particles into the lower chamber of the 1# and 2# split double-temperature zone pressure infiltration device respectively, and put 7 kg of 65.2Ag-34.2Cu-0.6Cr alloy into the molten metal crucible in the upper chamber of the induction heating furnace of the split double-temperature zone pressure infiltration device; first, cover the 2# vacuum air pressure infiltration furnace lower chamber with the furnace cover, introduce inert gas, turn on the heating power, and control the temperature to be 900℃; the 1# vacuum air pressure infiltration furnace lower chamber is connected with the upper chamber of the induction heating furnace through the slot rotation type connection; vacuumize the induction heating furnace upper chamber and the 1# vacuum air pressure infiltration furnace lower chamber at the same time through the vacuum pump on one side of the 1# vacuum air pressure infiltration furnace lower chamber, and when the vacuum degree in the chamber is reduced to 4×10 -1 After the vacuum degree in the chamber is reduced to 4×10

[0094] S4: Open the slot rotation type connection on both sides of the induction heating furnace upper chamber and the 1# vacuum air pressure infiltration furnace lower chamber, quickly remove the induction heating furnace upper chamber, rotate the 1# vacuum air pressure infiltration furnace lower chamber cover, and seal the 1# vacuum air pressure infiltration furnace lower chamber; after the 1# vacuum air pressure infiltration furnace lower chamber is filled with high-pressure high-purity inert gas to 10 MPa, keep the temperature and pressure constant for 10 min, and complete the compounding between the silver-copper matrix and the diamond; stop heating the 1# vacuum air pressure infiltration furnace lower chamber, cool down with the furnace, and take out the diamond / silver-copper matrix composite material when the temperature is below 200℃; during the cooling process of the 1# vacuum air pressure infiltration furnace lower chamber, open the 2# vacuum air pressure infiltration furnace lower chamber cover, quickly rotate the induction heating upper chamber, and quickly connect the cable of the induction heating furnace upper chamber; then open the induction heating furnace cover, put in 7 kg of 65.2Ag-34.2Cu-0.6Cr alloy, vacuumize the induction heating furnace upper chamber and the 2# vacuum air pressure infiltration furnace lower chamber at the same time through the vacuum pump on one side of the 2# vacuum air pressure infiltration furnace lower chamber, and when the vacuum degree in the chamber is reduced to 4×10 -1After Pa, the heating device is started to make the temperature of the upper chamber of the induction heating furnace 970℃, the temperature of the lower chamber of the 2# vacuum gas pressure infiltration furnace keeps at 900℃, after the 65.2Ag-34.2Cu-0.6Cr alloy in the upper chamber of the induction heating furnace is melted, the lifting rod in the crucible of the molten metal in the upper chamber of the induction heating furnace is lifted, and the molten 65.2Ag-34.2Cu-0.6Cr alloy in the upper chamber of the induction heating furnace flows into the forming mold in the lower chamber of the 2# vacuum gas pressure infiltration furnace through the small hole by itself; then the heating of the upper chamber of the induction heating furnace is stopped, the vacuumizing is also stopped, the high-purity inert gas is filled into the lower chamber of the 2# vacuum gas pressure infiltration furnace, and the filling of the gas is stopped after the upper and lower chambers reach the normal pressure; the screw-in clamping slots on the two sides of the upper chamber of the induction heating furnace and the lower chamber of the 2# vacuum gas pressure infiltration furnace are opened, the upper chamber of the induction heating furnace is quickly removed, the cover of the lower chamber of the 2# vacuum gas pressure infiltration furnace is screwed in, and the lower chamber of the 2# vacuum gas pressure infiltration furnace is sealed; after the high-pressure high-purity inert gas is filled into the lower chamber of the 2# vacuum gas pressure infiltration furnace to 10 MPa, the temperature and pressure are kept constant for 10 min, and the compounding between the silver-copper matrix and the diamond is completed; the heating of the lower chamber of the 2# vacuum gas pressure infiltration furnace is stopped, the furnace is cooled, and the diamond / silver-copper matrix composite material is taken out when the temperature is below 200℃.

[0095] Comparative Example 1

[0096] A method for preparing a high-thermal-conductivity diamond / silver-copper matrix composite material, the preparation process is the same as that in Example 2, except that the 70Ag-29.2Cu-0.8Cr alloy in steps S3 and S4 is replaced by a 70Ag-30Cu alloy.

[0097] It is found that the volume fraction of the diamond particles in the diamond / silver-copper composite material obtained in the comparative example is 55%, the surface of the diamond particles has no chromium carbide layer, and the thermal conductivity of the composite material is only 436 W / (m·K); compared with Example 2, the silver-copper matrix alloy in Comparative Example 1 does not contain chromium elements, and the thermal conductivity is reduced by 46.6% under the same preparation conditions.

[0098] Therefore, the chromium element in the silver-copper alloy matrix in Example 2 plays a key role in reducing the interfacial thermal resistance between the diamond particles and the silver-copper matrix alloy and obtaining a high-thermal-conductivity diamond / silver-copper matrix composite material.

[0099] Comparative Example 2

[0100] A method for preparing a high-thermal-conductivity diamond / silver-copper matrix composite material, the preparation process is the same as that in Example 3, except that the 70Ag-29.3Cu-0.5Zr alloy in steps S3 and S4 is replaced by a Cu-1.2Zr alloy, and the temperature of the upper chamber of the induction heating furnace is 1250℃ and the temperature of the lower chamber of the vacuum gas pressure infiltration furnace is 1150℃ in step S3.

[0101] It is measured that the volume fraction of diamond in the diamond / copper-based composite material obtained in the embodiment is 80%, the thickness of the zirconium carbide layer on the surface of the diamond particles is 460 nm, the density of the composite material is 98.5%, and the thermal conductivity is 785 W / (m·K); compared with Example 3, the matrix alloy of Comparative Example 2 is replaced by a high-melting-point copper-zirconium alloy from a low-melting-point silver-copper-zirconium alloy, which causes the temperature of the upper chamber of the induction heating furnace to increase from 980°C to 1250°C, and the temperature of the lower chamber of the vacuum pressure infiltration furnace to increase from 860°C to 1150°C. The higher preparation temperature causes the thickness of the zirconium carbide layer on the surface of the diamond particles to increase by 78.3%, the density of the composite material to decrease by 1%, and finally the thermal conductivity of the composite material to decrease by 31.9%;

[0102] Therefore, the silver in the silver-copper alloy matrix in Example 3 accounts for 60-70% by mass, which plays a key role in reducing the preparation temperature, reducing the thickness of the carbide layer on the surface of the diamond particles, and finally obtaining a high-thermal-conductivity diamond-reinforced silver-copper-based composite material.

[0103] The above is only a preferred embodiment of the present application, and does not limit the present application in any form. Any person skilled in the art can make many possible changes and modifications to the technical solutions of the present application, or modify equivalent embodiments, without departing from the spirit and technical solutions of the present application, by using the disclosed methods and technical contents. Therefore, any simple modification, equivalent replacement, equivalent change and modification of the above embodiments according to the technical essence of the present application, which does not deviate from the technical solutions of the present application, still belongs to the protection scope of the technical solutions of the present application.

Claims

1. A method for preparing a high thermal conductivity diamond / silver copper-based composite material, characterized in that: It comprises the following steps: S1: acid washing, alkali washing, anhydrous ethanol cleaning pretreatment is carried out to diamond particles, and drying is carried out; The particle size of the diamond particles is 45-450 μm; S2: the diamond particles pretreated in the above step are filled in a forming mold (9), and then a vibrating machine is vibrated to form a diamond blank; S3: the diamond blank obtained in the previous step is placed in the lower chamber (2) of the vacuum air pressure infiltration furnace of the split double-temperature-zone pressure infiltration device together with the forming mold (9), and the silver-copper matrix alloy is placed in the molten metal crucible (4) of the upper chamber (1) of the induction heating furnace; then the upper chamber (1) of the induction heating furnace and the lower chamber (2) of the vacuum air pressure infiltration furnace are vacuumized, and when the vacuum degree is reduced to 10-10 Pa, the upper chamber (1) of the induction heating furnace and the lower chamber (2) of the vacuum air pressure infiltration furnace are heated, and after the upper chamber (1) of the induction heating furnace and the lower chamber (2) of the vacuum air pressure infiltration furnace respectively reach the set temperature and are kept constant, the molten silver-copper matrix alloy is poured into the forming mold; the heating and vacuumization of the upper chamber (1) of the induction heating furnace are stopped, high-purity inert gas is introduced from the lower chamber (2) of the vacuum air pressure infiltration furnace, and the pressure in the furnace is increased to atmospheric pressure, and then the gas introduction is stopped; -2 Pa, and after the upper chamber (1) of the induction heating furnace and the lower chamber (2) of the vacuum air pressure infiltration furnace respectively reach the set temperature and are kept constant, the molten silver-copper matrix alloy is poured into the forming mold; the heating and vacuumization of the upper chamber (1) of the induction heating furnace are stopped, high-purity inert gas is introduced from the lower chamber (2) of the vacuum air pressure infiltration furnace, and the pressure in the furnace is increased to atmospheric pressure, and then the gas introduction is stopped; The silver copper matrix alloy is silver copper chromium alloy or silver copper zirconium alloy, and the composition of the silver copper matrix alloy is Ag: 60-70%, Cr or Zr: 0.5-1.2%, Cu: the balance; The upper chamber (1) of the induction heating furnace is provided with a lifting rod (14), and the lifting rod (14) passes through the bottom of the molten metal crucible (4) from the top of the upper chamber (1) of the induction heating furnace and corresponds to the flow hole (11); The lower chamber (2) of the vacuum gas pressure infiltration furnace is provided with a furnace cover (12), and the lower chamber (2) of the vacuum gas pressure infiltration furnace is connected with the furnace cover (12) through a rotating slot; The upper chamber (1) of the induction heating furnace and the lower chamber (2) of the vacuum gas pressure infiltration furnace are both double-layer water circulation metal shells; The heating of the upper chamber (1) of the induction heating furnace adopts induction heating, and the heating rate is 200-300 ℃ / min; The heating of the lower chamber (2) of the vacuum gas pressure infiltration furnace adopts graphite heating element (8) heating, and the heating rate is 10-20 ℃ / min; The infiltration composite mold of the lower chamber (2) of the vacuum gas pressure infiltration furnace comprises a graphite crucible (13) and a forming mold (9); The inner and outer layers of the bell jar type heat preservation cylinder (10) in the lower chamber (2) of the vacuum gas pressure infiltration furnace are metal sheets, which are connected by riveting or welding process, and the heat preservation material is filled between the two sheets; The setting temperature of the upper chamber (1) of the induction heating furnace is 950-1050 ℃, and the setting temperature of the lower chamber (2) of the vacuum gas pressure infiltration furnace is 860-950 ℃; S4: quickly disassemble the upper chamber (1) of the induction heating furnace, and rotate the furnace cover (12) of the lower chamber (2) of the vacuum gas pressure infiltration furnace; After the high-pressure high-purity inert gas is introduced into the lower chamber (2) of the vacuum gas pressure infiltration furnace to 5-20 MPa, the silver copper matrix alloy melt infiltrates into the pores of the diamond particles under the action of gas pressure, while the chromium or zirconium elements in the silver copper matrix alloy melt react with the diamond particles to form a carbonized chromium or zirconium layer with a thickness of 100-200 nm on the surface of the diamond particles; After constant temperature and pressure for 5-20 min, the heating power is turned off and the furnace is cooled to below 200 ℃, a high-thermal-conductivity diamond / silver copper matrix composite material is obtained, the volume fraction of the diamond particle reinforced phase in the high-thermal-conductivity diamond / silver copper matrix composite material is 40-80%, the thickness of the carbonized chromium layer on the surface of the diamond particle is 100-200 nm, the density of the composite material reaches 99.1-99.5%, and the thermal conductivity is 720-1152 W / (m·K); The split type double-temperature zone pressure infiltration device of S3 comprises a detachable induction heating furnace upper chamber (1), a vacuum air pressure infiltration furnace lower chamber (2), a vacuum system, an air charging system and an electrical control system; the vacuum air pressure infiltration furnace lower chamber (2) is connected with the vacuum system and the air charging system, and the electrical control system controls the whole split type double-temperature zone pressure infiltration device. The induction heating furnace upper chamber (1) is a medium-frequency induction furnace, and from outside to inside, it comprises a medium-frequency induction furnace shell (3), an induction coil (5) and a molten metal crucible (4); the induction heating furnace upper chamber (1) is connected with a medium-frequency power source through a cable, wherein the cable is a detachable structure. The vacuum air pressure infiltration furnace lower chamber (2) comprises, from outside to inside, a bell jar type heat preservation cylinder (10), a graphite heating body (8) and an infiltration composite mold; the bottom of the vacuum air pressure infiltration furnace lower chamber (2) is provided with an air charging interface (6) and a vacuum interface (7); The bottom of the induction heating furnace upper chamber (1) and the top of the bell jar type heat preservation cylinder (10) of the vacuum air pressure infiltration furnace lower chamber (2) are both provided with a metal liquid flow hole (11), and the induction heating furnace upper chamber (1) and the vacuum air pressure infiltration furnace lower chamber (2) are connected through a screw-in type clamping groove. The induction heating furnace upper chamber (1) is combined with 2-5 vacuum air pressure infiltration furnace lower chambers (2) to perform step-by-step production.

2. The method of claim 1, wherein the method comprises the steps of: In step S3, the molten silver copper matrix alloy liquid is poured into the forming mold (9) after constant temperature, the lifting rod (14) in the molten metal crucible (4) of the induction heating furnace upper chamber (1) is lifted, and the silver copper matrix alloy liquid flows into the forming mold (9) of the vacuum air pressure infiltration furnace lower chamber (2) through the flow hole (11). ​ 3. The method of claim 1, wherein the method further comprises: The upper chamber (1) of the induction heating furnace in step S3 is combined with the lower chamber (2) of the vacuum gas pressure infiltration furnace 2-5 to perform step-by-step production, specifically: when the upper chamber (1) of the induction heating furnace is combined with the lower chamber (2) of the first vacuum gas pressure infiltration furnace, the second to fifth vacuum gas pressure infiltration furnaces are placed with the forming mold (9) containing the diamond blank; and the heating power is sequentially turned on under the protection of inert gas; after the silver-copper matrix alloy is melted and poured into the forming mold (9) of the lower chamber (2) of the first vacuum gas pressure infiltration furnace, the upper chamber (1) of the induction heating furnace is quickly separated from the lower chamber (2) of the first vacuum gas pressure infiltration furnace, and the first vacuum gas pressure infiltration furnace is further operated in step S4; the cover (12) of the lower chamber of the second vacuum gas pressure infiltration furnace is opened, the upper chamber (1) of the induction heating furnace is screwed in, and the cable of the upper chamber of the induction heating furnace is quickly connected; then the cover of the induction heating furnace is opened, the silver-copper matrix alloy is placed, the power is turned on to heat and melt the silver-copper matrix alloy; next, the vacuum system of the lower chamber (2) of the second vacuum gas pressure infiltration furnace is opened, and vacuum is started; after the upper chamber (1) of the induction heating furnace and the lower chamber (2) of the vacuum gas pressure infiltration furnace reach the program setting temperature, the following steps are performed: "lift the lifting rod (14)-pour the silver-copper matrix alloy melt-close the vacuum system-charge to normal pressure-separate the upper chamber (1) of the induction heating furnace from the lower chamber (2) of the vacuum gas pressure infiltration furnace-perform step S4 operation of the vacuum gas pressure infiltration furnace"; then the upper chamber (1) of the induction heating furnace is sequentially combined with the third, fourth and fifth lower chambers (2) of the vacuum gas pressure infiltration furnace in turn to perform step-by-step production. ​ 4. The method of claim 1, wherein the high thermal conductivity diamond / silver copper composite material is prepared by the steps of: The step S4 is specifically: the screw-in clamping slots on both sides of the upper chamber (1) of the induction heating furnace and the lower chamber (2) of the vacuum gas pressure infiltration furnace are opened, the upper chamber (1) of the induction heating furnace is quickly removed, the cover (12) of the lower chamber of the vacuum gas pressure infiltration furnace is screwed in, and the lower chamber (2) of the vacuum gas pressure infiltration furnace is sealed; after the high-pressure high-purity inert gas is filled into the lower chamber (2) of the vacuum gas pressure infiltration furnace to 5-20 MPa, the temperature and pressure are kept constant for 5-20 min, the compounding between the silver-copper matrix alloy and the diamond is completed; the heating of the lower chamber (2) of the vacuum gas pressure infiltration furnace is stopped, and the furnace is cooled; when the temperature is below 200℃, the diamond / silver-copper matrix composite material is taken out. ​ 5. A high thermal conductivity diamond / silver-copper based composite material, characterized by: The high-thermal-conductivity diamond / silver-copper matrix composite material is prepared by the method of any one of claims 1-4, the volume fraction of the diamond particle reinforcing phase in the high-thermal-conductivity diamond / silver-copper matrix composite material is 40-80%, the thickness of the chromium carbide layer on the surface of the diamond particle is 100-200 nm, the density of the composite material is 99.1-99.5%, and the thermal conductivity is 720-1152 W / (m·K).

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