Preparation method of diamond-copper composite heat sink with high-heat-conduction path

Abstract

The invention relates to a preparation method of a diamond-copper composite heat sink with a high-heat-conduction passage. According to the method, a diamond / copper composite heat conduction framework with a bionic fractal structure is prepared through an extrusion type additive manufacturing technology, and then the diamond / copper composite heat sink with high heat conduction, high communication and high density is obtained through degreasing, sintering and infiltration processes. The problem that a complex structure is difficult to achieve through a traditional processing method is solved, meanwhile, a high-speed heat conduction channel with preferred orientation is constructed in the heat sink, and therefore the heat dissipation performance of the composite material is remarkably improved, and the composite material is suitable for heat management of high-power electronic equipment.

Description

TECHNICAL FIELD

[0001] The application relates to a preparation method of a diamond copper composite heat sink with a high heat conduction path, and belongs to the technical field of development of heat dissipation composite materials. BACKGROUND

[0002] With the rapid development of power devices towards high power density and high integration, the heat dissipation capacity has become a key bottleneck restricting the performance breakthrough. At present, the rapid development of new energy vehicles, 5G communication and artificial intelligence promotes the heat flow density of power devices to generally break through 500W / cm 2 The traditional heat dissipation technology is limited by the performance bottleneck of materials, and it is difficult to cope with the heat dissipation challenge of current high power density devices, so innovative solutions are urgently needed. Diamond-based composite materials have high thermal conductivity and low thermal expansion characteristics of diamond, and combine the excellent performance of metal materials in heat conduction and electrical conductivity and mechanical processing, showing outstanding comprehensive advantages. Among them, represented by diamond / copper composite materials, the theoretical thermal conductivity of such materials can exceed 1000W / mK, which is five times that of the third generation packaging materials.

[0003] The actual thermal conductivity of diamond-based composite materials is still significantly lower than expected, and has not yet been widely applied. The main reason for this problem is the insufficient wettability and bonding difficulty of the heterogeneous interface between diamond and metal, as well as the mismatch of C atoms and metal phonon vibration spectrum, which causes high interface thermal resistance. In order to improve the interface bonding, researchers have carried out research from the aspects of diamond surface metallization, matrix alloying and preparation process optimization. However, these studies are mostly focused on the regulation of the interface, and the optimization of the overall heat transfer network structure of the material is relatively insufficient. In fact, the configuration of the diamond skeleton plays a crucial role in determining the spatial distribution of particles and the main heat dissipation path. Through reasonable design and regulation of the skeleton configuration, a preferentially oriented high-speed heat conduction channel can be constructed, thereby further improving the overall heat transfer efficiency of the composite material on a macro scale.

[0004] It is also an important development direction of heat management material configuration to apply biomimetic fractal structure to composite material heat transfer enhancement. As an important branch of the application of fractal theory in the field of heat transfer, biomimetic structures such as tree branches, leaf veins and blood vessels have attracted widespread attention from scholars at home and abroad in recent years due to their excellent heat and mass transfer performance. However, it is difficult to effectively control and accurately shape the biomimetic structure of the material at multiple scales by traditional manufacturing and processing methods. Therefore, it is urgent to develop new composite material design concepts and preparation methods to maximize the designability and composite effect of composite materials to break through the limitations of existing composite methods and material performance. Additive manufacturing breaks through the bottleneck of manufacturing complex special-shaped components in principle, can realize the coordinated and controllable shaping of the microstructure and macrostructure of the material, thereby significantly expanding the structural diversity of heat conduction products and giving the heat conduction composite material a more complete orientation feature, effectively improving its heat management performance. Compared with traditional processing methods, indirect additive manufacturing provides a new technical approach for the complex configuration design of diamond composite materials. Among them, powder extrusion 3D printing (PEP) as an indirect additive manufacturing method similar to FDM, combined with debinding and sintering in powder metallurgy, can realize the alternate extrusion and accurate shaping of multi-component materials at low temperature, thereby preparing a mold-free green body with complex structure. The subsequent densification of the skeleton and copper can be realized by infiltration method, providing ideal samples for the subsequent study of the configuration factor on the thermal physical properties and mechanical properties. Compared with direct additive manufacturing technologies such as laser or electron beam, the use of PEP to build diamond skeletons can effectively avoid the problem of thermal damage, providing a feasible way for fine and controllable heat conduction structure design. However, there are still few reports on the use of additive manufacturing technology to customize diamond copper composite heat conduction skeletons and prepare diamond copper composite heat sinks with high thermal conductivity, high connectivity and high density through subsequent debinding and metal pressure infiltration processes. SUMMARY

[0005] The purpose of the present application is to solve the technical bottleneck of existing diamond-based composite materials in improving the heat conduction performance, especially in the heat management demand of high-power electronic equipment and other high-performance applications, to break through the problem of interfacial thermal resistance between diamond and matrix, and to further improve the overall heat conduction performance of the material. Although diamond composite materials have excellent theoretical thermal conductivity, traditional homogeneous structure design faces a huge interfacial thermal resistance problem, which makes it difficult to fully utilize its heat conduction potential and limits its practical application effect. The present application constructs a diamond copper skeleton structure with directional heat conduction channels, thereby effectively reducing the interfacial thermal resistance and significantly improving the heat conduction performance of the material. However, it is difficult to construct complex structures inside the diamond copper composite material, which is a major obstacle to the realization of efficient heat dissipation.

[0006] In view of the above technical barriers, the application innovatively adopts an extrusion type additive manufacturing technology. The technology can realize accurate control of the geometry, size and distribution of the internal microchannels of the composite material, effectively solving the core problem of difficulty in processing and high manufacturing cost of complex microchannel structures. Through this manufacturing method, an internal three-dimensional network structure with high precision can be formed.

[0007] Based on the above manufacturing process, the application further provides a specific preparation method. The method uses diamond composite particles to first prepare a diamond copper composite heat conduction skeleton with a biomimetic fractal structure by using the extrusion type additive manufacturing technology, and then obtains a high-thermal-conductivity, high-connection and high-density diamond copper composite heat sink product through a debinding, sintering and infiltration process. The diamond copper composite heat conduction skeleton with a biomimetic fractal structure contains copper, and the infiltrating agent is selected from at least one of copper and copper-containing alloys (including copper alloys) during the infiltration.

[0008] In the application, the structure of the diamond copper composite material heat conduction skeleton used can be a biomimetic fractal structure that has been verified in recent years to have excellent heat and mass transfer performance.

[0009] Before the additive manufacturing printing of the diamond copper composite material heat conduction skeleton, the diamond used is a diamond composite particle with a modified layer; in the diamond composite particle, the core is a diamond particle and the outside is a modified layer, and the thickness of the modified layer is 40-60 nm. As a preferred, the particle size of the diamond particle is 10-60 μm, preferably 20-40 μm.

[0010] In industrial applications, the middle modified layer is prepared by a magnetron sputtering method, the metal is added to the internal mixer together with the modified diamond particles in the mixing process, and the metal layer is formed by uniform stirring. The material of the metal shell layer is preferably Cu, and the intermediate transition layer between the diamond and the copper is preferably B, Cr, W or Zr.

[0011] Process parameters of the magnetron sputtering method: vacuum degree: 10 -2 -10 -3 Pa; material: high-purity (≥99.99%) B (Cr, W) target; size: diameter 100-150 mm, preferably 120-130 mm; substrate temperature: 150-250°C, preferably 180-220°C; sputtering power: 180-220 W, preferably 190-210 W; sputtering time: 20-40 min, preferably 25-30 min; gas flow: 30-50 sccm, preferably 35-45 sccm; working gas: high-purity argon (purity ≥99.999%).

[0012] Before additive manufacturing printing the diamond copper composite heat conducting framework, the modified diamond particles, copper and binder are mixed in a volume ratio of 45-47:18-20:34-36, the binder is a wax-based binder system, the wax-based binder system is composed of PW, PE, PA and SA in a mass ratio of PW:PE:PA:SA=59-61:19-21:14-16:4-6, and a composite material feedstock suitable for extrusion molding is prepared.

[0013] In the present application, the modified diamond particles, copper and binder are controlled in a volume ratio of 45-47:18-20:34-36, because this formula ratio can ensure the printing formability while meeting the strength requirements of the sample after sintering, and too much modified diamond particles and / or copper will lead to subsequent printing failure. If the binder is too much, the bonding strength of the sample after debinding and sintering will be reduced. In the present application, the modified diamond particles and copper are controlled in a volume ratio of 45-47:18-20, because under this formula ratio, the sample after debinding and sintering can form a high-connectivity oriented heat conduction path framework structure with certain bonding strength. If the proportion of copper relative to the modified diamond particles is too large, it will lead to problems such as the inability to form a high-connectivity oriented heat conduction path, and if the proportion of the modified diamond particles relative to the copper is too large, it will lead to a decrease in the bonding strength of the sample.

[0014] As a preferred, before additive manufacturing printing the diamond copper composite heat conducting framework, the modified diamond particles, copper and binder are mixed in a volume ratio of 46:19:35, the binder is a wax-based binder system, the wax-based binder system is composed of PW, PE, PA and SA in a mass ratio of PW (paraffin):PE (polyethylene):PA (polyamide):SA (stearic acid)=60:20:15:5, and a composite material feedstock suitable for extrusion molding is prepared. The particle size range of the feedstock is 0.1-0.3mm.

[0015] The additive manufacturing prints the diamond copper composite heat conducting framework, preferably an extrusion molding process, the parameters of the extrusion molding process are controlled as follows: extruder nozzle diameter: 0.8mm; platform temperature: 95-105℃, preferably; printing temperature: 140-170℃, preferably 150-160℃; retraction compensation coefficient: 0.5-0.6, preferably 0.53-0.57. In the present application, the retraction compensation coefficient refers to: the retraction compensation coefficient is a parameter used to adjust the retraction amount of the extruder in powder extrusion printing, and the main function is to prevent material leakage or material breakage when the printing head moves. This parameter needs to be optimized according to the material characteristics (density, melt index, fluidity, and viscous flow state). The default initial value is usually 0.5 in industrial applications. On this basis, the range of the retraction compensation coefficient is determined by two hollow square columns distributed at intervals. The retraction compensation is turned on during the nozzle movement. If there is material overflow at the starting point of the second square column, it means that the retraction compensation coefficient is too small. If there is material shortage at the starting point, it means that the retraction compensation coefficient is too large. By accurately adjusting this parameter, the printing quality can be ensured, and problems such as material accumulation, pore defects, and surface roughness can be avoided.

[0016] The extrusion molding is defatted to obtain a defatted green body, and the defatting includes solvent defatting and thermal defatting.

[0017] During solvent defatting, the solvent is n-heptane; the defatting temperature is 25-35℃, preferably 28-32℃; the defatting time is 5-7h, preferably 5.5-6.5h; during thermal defatting, the defatting atmosphere is hydrogen, the hydrogen flow rate is 2-5L / min, preferably 3-4L / min, and the temperature is raised to 250℃, 400℃, and 600℃ at a heating rate of 1-2℃ / min, and is held for 80-120min respectively. The heating rate is preferably 1-1.5℃ / min, and the holding time is preferably 90-110min.

[0018] The defatted green body is pre-sintered to obtain a sintered body, and the sintering is controlled as follows: the pre-sintering temperature is 1000-1100℃, preferably 1050-1085℃ (including 1075-1085℃); the holding time is 50-80min, preferably 60-70min; the heating rate is 1-4℃ / min, preferably 2-3℃ / min; the sintering atmosphere is hydrogen, and the hydrogen flow rate is 2-5L / min, preferably 3-4L / min;

[0019] The heat-conducting metal particles are used as the infiltrating material, the infiltrating material is placed in the container in a set manner with the sintered blank, and the sample is obtained by heating and infiltrating. The infiltrating temperature is the melting point of the infiltrating material + A degrees Celsius, and the value of A is 50-120. As preferred, when the infiltrating material is copper, the infiltrating process parameters are as follows: infiltrating temperature: 1130-1200 DEG C, preferably 1150-1180 DEG C; infiltrating time: 30-60 min, preferably 40-50 min; pressure range: 5-15 MPa, preferably 8-12 MPa.

[0020] The mass ratio of copper in the printing blank to the mass of copper in the product is 0.2-0.35:1, because the material can form a high-connection-orientation heat-conducting path and maintain uniform density at this ratio. If the copper content in the printing blank is too high, it will lead to the failure to form a high-connection-orientation heat-conducting path. If it is too low, it will not meet the mechanical property requirements of the material during infiltration.

[0021] The present application successfully solves the problems of insufficient heat-conducting performance, poor density and difficulty in preparing complex geometric shapes of existing diamond composite materials by using diamond composite particles, extrusion type additive manufacturing technology and infiltration process, and the specific effects are as follows:

[0022] The extrusion type additive manufacturing technology is used to prepare a diamond copper composite heat-conducting skeleton with a biomimetic fractal structure. This method overcomes the limitations of traditional mechanical processing or mold forming in precision, cost and structural integrity, and avoids the problems of heat loss, cracking and the like of directly additive manufacturing diamond surface. Subsequently, through the defatting, sintering and infiltration processes, a high-heat-conducting, high-connection, high-dense diamond copper composite heat sink is obtained. BRIEF DESCRIPTION OF DRAWINGS

[0023] ATTACHMENT Figure 1 The compression resistance sample and the thermal conductivity sample selected from the product obtained by the extrusion type additive manufacturing of embodiment 1;

[0024] ATTACHMENT Figure 2 The biomimetic diamond copper skeleton structure obtained according to the parameters of embodiment 1 according to the set pattern;

[0025] ATTACHMENT Figure 3 The mechanical property curve of the product obtained in embodiment 2.

[0026] ATTACHMENT Figure 4 The SEM image of the internal diamond micro-morphology of the product obtained in embodiment 2;

[0027] ATTACHMENT Figure 5 The BSE image of the microstructure of the product obtained in embodiment 2;

[0028] ATTACHMENT Figure 6 The BSE image of the microstructure of the product obtained in embodiment 2.

[0029] Appendix Figure 1 This exhibit displays standard mechanical property test specimens and thermal conductivity test specimens prepared using this process. The specimen on the left is the sample required for mechanical property testing, and the three particles on the right are the sample for thermal conductivity testing.

[0030] From the appendix Figure 2 It can be seen that biomimetic fractal diamond framework structures with a certain degree of precision can be successfully prepared through extrusion additive manufacturing technology.

[0031] From the appendix Figure 3 It can be seen that the compressive strength of the sample is greater than 17 MPa, which meets the requirements of the melt infiltration process.

[0032] From the appendix Figure 4 It can be seen that the internal sintering neck size of the sample is moderate, effective connection is formed between copper, and good interfacial bonding is formed between diamond and copper. At the same time, diamonds are in direct contact with each other, forming a highly interconnected and oriented thermally conductive network.

[0033] From the appendix Figure 5 It can be seen that the diamond particles have a smooth surface and no heat loss problems such as cracks or graphitization;

[0034] From the appendix Figure 6 It can be seen that the diamond and copper are evenly distributed inside the sample, and there is no agglomeration.

[0035] Specific implementation methods

[0036] Example 1

[0037] The diamond particles selected have a particle size of approximately 30-40 μm, and are used in a vacuum of 10... -3 Under the conditions of Pa, substrate temperature 200℃, sputtering power 200W, sputtering time 30min, and argon gas flow rate 40sccm, a 50nm thick Cr transition layer was deposited on the surface of diamond particles by magnetron sputtering. Modified diamond particles, copper powder, and wax-based binder (PW:PE:PA:SA = 60:20:15:5) were mixed together in an internal mixer at a volume ratio of 46:19:35 to prepare a uniformly shaped irregular polyhedral feedstock suitable for extrusion molding. The structure was printed using an extruder with a nozzle diameter of 0.8mm at a printing temperature of 155℃, a plateau temperature of 100℃, and a pullback compensation coefficient of 0.55. The surface quality of the printed blank was good, with no collapse, cracks, pores, or fissures.

[0038] Explore Cases 1-4

[0039] The printing process in Example 1 was changed, and the remaining conditions were the same as in Example 1, and the printed copper-diamond composite material was subjected to comparative tests. The results of Examples 1 and Examples 1-4 are shown in Table 1. In Example 1, under the combined action of reasonable printing temperature, platform temperature and backflow compensation coefficient, the material rheological response (shear rate) and device kinetic characteristics (screw response time) are optimally matched, and the dual requirements of extrusion stability and forming precision can be simultaneously realized. In Example 1, when the printing temperature is lower than 150℃, the material will cause insufficient plasticization due to insufficient thermal history, which is manifested by abnormal increase of melt viscosity, resulting in significant decrease of screw conveying efficiency, and finally causing mechanical blockage and extrusion interruption; in Example 2, when the processing temperature exceeds 160℃, the degradation of molecular chain accelerates, resulting in a decrease in melt strength, and the melt exhibits obvious viscoelastic imbalance characteristics, which is prone to cause melt rupture during extrusion molding, accompanied by periodic material breakage; in Example 3, the printing temperature is lower than 100℃, and the temperature difference in the temperature field is large, so the models with a thickness of less than 2.0 mm are prone to cracking; in Example 4, the printing temperature is higher than 100℃, and the bottom temperature of the material after extrusion is too high, which is not easy to form; in Example 5, when the backflow compensation coefficient is lower than 0.5, the residual pressure gradient in the nozzle cavity is insufficient, resulting in melt seepage phenomenon during the non-printing stage, causing material overflow at the edge of the printing path (increasing the surface roughness Ra), resulting in insufficient volume flow recovery during the extrusion restart stage, and forming a microcavity at the starting point of the path; in Example 6, when the backflow compensation coefficient exceeds 0.6, the screw reset delay time is prolonged, causing material supply lag at the printing starting point, resulting in micro-pore defects between layers, causing extrusion overshoot effect, causing feature structure profile distortion and surface waviness defects.

[0040]

[0041] Example 2

[0042] On the basis of Example 1, the printed blank was subjected to debinding and pre-sintering. During solvent debinding, the debinding temperature was 30℃, and the debinding time was 6h; during thermal debinding, the debinding atmosphere was hydrogen, the gas flow rate was 3L / min, the temperature was raised to 250℃ at a rate of 1℃ / min and held for 100min, then the temperature was raised to 400℃ at a rate of 1℃ / min and held for 100min, then the temperature was raised to 600℃ at a rate of 1℃ / min and held for 100min, and finally the temperature was raised to 1080℃ at a rate of 2℃ / min and held for 60min for pre-sintering. The sintered blank had no defects such as collapse and cracking, and had good shape retention; the compressive strength reached 17MPa, meeting the requirements of the subsequent infiltration process.

[0043] Examples 7-10

[0044] The sintering parameters in Example 2 were changed, and the rest of the conditions were the same as in Example 2. The copper-diamond composite material prepared by the debinding and pre-sintering printing blank was subjected to a comparative test. The comparison results of Example 2 and exploration examples 11-14 are shown in Table 3. In Example 2, because the holding time and sintering temperature are both good, the debinding and sintered sample forms a good sintering neck, the diamond-copper interface is well combined, the copper distribution uniformity is good, and no deformation occurs, so as to facilitate the subsequent gas pressure infiltration process; in exploration example 7, long time at high temperature leads to copper aggregation and growth, resulting in uneven distribution of copper matrix, and a large number of diamonds exist in the form of mechanical engagement, resulting in poor sample interface bonding; in exploration example 8, there is not enough time for copper particles to form good neck connection and diffusion, resulting in low skeleton strength; in exploration example 9, the thermal diffusion is low, and the copper particles cannot form good neck connection and diffusion, resulting in low skeleton strength; in exploration example 10, the temperature exceeds the melting point of copper, and pure copper is exuded from the surface of the sample, and there is no sintering neck inside.

[0045]

[0046] Example 3

[0047] On the basis of Example 2, the debinding and pre-sintering blank was subjected to infiltration. The infiltration method was gas pressure infiltration, the infiltration material was Cu, the infiltration temperature was 1150℃, the infiltration time was 50min, and the infiltration pressure was 10MPa. After completing the infiltration, the temperature was reduced to 600℃ at a rate of 5℃ / min, and then the furnace was cooled to room temperature. The temperature was reduced synchronously with the pressure reduction, and a diamond-copper composite material with a high connected orientation skeleton inside was obtained. The density reached 98%, and the thermal conductivity reached 461W / mk.

[0048] Exploration examples 11-14

[0049] The infiltration process in Example 3 was changed, and the rest of the conditions were the same as in Example 3. The copper-diamond composite material prepared was subjected to a comparative test. The comparison results of Example 3 and exploration examples 11-14 are shown in Table 4. In Example 3, the reasonable infiltration time and infiltration temperature, full infiltration, high composite material density, good interface transition layer, and high interface bonding strength; in exploration example 11, the temperature is too low, resulting in high copper melt viscosity and poor flowability, and poor interface wettability, and local incomplete infiltration; in exploration example 12, high temperature accelerates the graphitization transformation of diamond, and causes uneven thermal expansion, resulting in increased internal stress and diamond breakage; in exploration example 13, long time holding causes the graphitization of diamond surface to be intensified through time accumulation effect, and the interface reaction layer is too thick, increasing the interface thermal resistance of the composite material; in exploration example 14, the holding time is too short, and the copper cannot overcome the flow resistance to completely infiltrate, and a uniform organization cannot be formed.

[0050] .

Claims

1. A method for preparing a diamond-copper composite heat sink with high thermal conductive paths, characterized in that: The diamond copper composite heat sink product is prepared by first preparing a diamond copper composite heat conducting skeleton with a biomimetic fractal structure by using an extrusion additive manufacturing technology, and then through a debinding, sintering and infiltration process, wherein the diamond copper composite heat conducting skeleton with a biomimetic fractal structure contains copper, and the infiltrant is at least one selected from copper and copper-containing alloy.

2. The method of claim 1, wherein the method further comprises: In the additive manufacturing printing of the green body of the diamond skeleton structure, the diamond used is diamond composite particles with a modified layer; in the diamond composite particles, the core is a diamond particle, and the outer layer is a modified layer, and the thickness of the modified layer is 40-60 nm; the particle size of the diamond particle is 10-60 μm, preferably 20-40 μm. ​ 3. The method of claim 1, wherein the method further comprises: The external modification layer is prepared by a magnetron sputtering method, the external layer metal is added into the internal mixer together with the modified diamond particles in a mixing process, and is stirred uniformly to form an external metal layer; the material of the metal shell layer includes Cu, and the intermediate modification layer between the diamond and the copper is preferably B, Cr, W or Zr; the process parameters of the magnetron sputtering method are as follows: vacuum degree: 10 -2 -10 -3 Pa; material: target material with purity ≥ 99.99%; target material size: diameter 100-150 mm; substrate temperature: 150-250 ℃; sputtering power: 180-220 W, preferably 190-210 W; sputtering time: 20-40 minn; gas flow: 30-50 sccm; working gas: argon with purity ≥ 99.999%. ​ 4. The method of claim 1, wherein the method further comprises: Before the additive manufacturing printing of the diamond copper composite heat conducting skeleton, the modified diamond particles, copper and a binder are mixed in a volume ratio of 45-47:18-20:34-36, the binder is a wax-based binder system, the wax-based binder system is composed of PW, PE, PA and SA in a mass ratio of PW:PE:PA:SA=59-61:19-21:14-16:4-6, and a composite material feed suitable for extrusion molding is prepared. ​ 5. The method of claim 4, wherein the method further comprises: Before the additive manufacturing printing of the diamond copper composite heat conducting skeleton, the modified diamond particles, copper and a binder are mixed in a volume ratio of 46:19:35, the binder is a wax-based binder system, the wax-based binder system is composed of PW, PE, PA and SA in a mass ratio of PW:PE:PA:SA=60:20:15:5, and a composite material feed suitable for extrusion molding is prepared.

6. The method of claim 1, wherein the method further comprises: The additive manufacturing printing of the diamond copper composite heat conducting skeleton is preferably an extrusion molding process, and the parameters of the extrusion molding process are controlled as follows: the diameter of the extruder nozzle is 0.8 mm; the platform temperature is 95-105°C, preferably; the printing temperature is 140-170°C, preferably 150-160°C; and the back-pull compensation coefficient is 0.5-0.6, preferably 0.53-0.

57.

7. The method of claim 1, wherein the method further comprises: The extrusion molding is debound to obtain a debound green body, and the debinding includes solvent debinding and thermal debinding; in the solvent debinding, the solvent is n-heptane, the debinding temperature is 25-35°C, preferably 28-32°C, and the debinding time is 5-7 h, preferably 5.5-6.5 h; in the thermal debinding, the debinding atmosphere is hydrogen, the hydrogen flow rate is 2-5 L / min, preferably 3-4 L / min, the temperature is raised to 250°C, 400°C and 600°C at a temperature raising rate of 1-2°C / min, and the temperature is maintained for 80-120 min, respectively; the temperature raising rate is preferably 1-1.5°C / min, and the holding time is preferably 90-110 min; the debound green body is pre-sintered to obtain a sintered body, and in the sintering, the pre-sintering temperature is controlled to be 1000-1100°C, preferably 1050-1085°C, the holding time is 50-80 min, preferably 60-70 min, and the temperature raising rate is 1-4°C / min, preferably 2-3°C / min; the sintering atmosphere is hydrogen, and the hydrogen flow rate is 2-5 L / min, preferably 3-4 L / min.

8. The method of claim 1, wherein the method further comprises: The heat-conducting metal particles are used as the infiltrating material, the infiltrating material is placed in the container in a set manner with the sintered blank, and the sample is obtained by heating and infiltrating; the infiltrating temperature is the melting point of the infiltrating material+A degrees Celsius, and the value of A is 50-120.

9. The method of claim 1, wherein the method further comprises: When the infiltrating material is copper, the infiltrating process parameters are as follows: the infiltrating temperature is 1130-1200 DEG C, preferably 1150-1180 DEG C; the infiltrating time is 30-60 min, preferably 40-50 min; and the pressure range is 5-15 MPa, preferably 8-12 MPa. ​ 10. The method of claim 9, wherein the method further comprises: The mass ratio of copper in the printing blank to copper in the product is 0.2-0.35:1.

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