Preparation method of high-thermal-conductivity diamond reinforced metal-based composite material

Abstract

The invention relates to the technical field of manufacturing of superhard materials, and discloses a preparation method of a high-thermal-conductivity diamond reinforced metal matrix composite, which comprises the following steps: S1, preparing materials: 18-25 parts of diamond powder, 5-8 parts of metal matrix, 6-8 parts of metal catalyst and 3-6 parts of treating fluid; compared with a common diamond copper heat-conducting material, the high-heat-conductivity diamond composite material has higher hardness and heat-conducting property, the hardness is improved by 15-20 times on the original basis, the heat-conducting property is improved by 2-3 times, the heat-conducting property of the prepared composite material is improved, and the reliability of the prepared composite material is improved; and the method is suitable for preparation of the bulk diamond reinforced metal matrix composite, industrial production and application are easy to achieve, the single-time yield can be remarkably increased, and the production efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of superhard material manufacturing, in particular to a method for preparing a high thermal conductivity diamond-reinforced metal-based composite material. Background Art

[0002] Thermally conductive materials are materials used to transfer heat and are commonly used in electronic devices, electrical appliances, automobiles, and other fields. With the continuous development of science and technology and the increasing performance requirements of electronic devices, the thermal conductive materials industry has a very broad prospect.

[0003] With the rapid development of electronic packaging technology, especially in electronic products such as mobile phones, computers, and televisions, which are increasingly pursuing thinner and lighter dimensions, the integration density of integrated circuits is increasing, while the size of electronic components is shrinking. This leads to an increasing heat generation per unit area and per unit time, and an increasing burden on electronic packaging materials to dissipate heat. Therefore, high thermal conductivity has become a must-have requirement for electronic packaging materials. Therefore, the development of new electronic packaging materials with high thermal conductivity, low density, and sufficient strength and rigidity is urgent. Diamond, with its excellent comprehensive thermophysical properties, is often used as an ideal reinforcement phase, combined with high thermal conductivity matrices such as Ag, Al, and Cu to form a new type of electronic packaging composite material.

[0004] Currently, the market mainly adopts the method of sintering a mixture of copper powder and diamond to make thermal conductive sheets. The thermal conductive sheets made by this method have low hardness and thermal conductivity, which will reduce the service life of the thermal conductive sheets and lead to poor thermal conductivity performance of the thermal conductive sheets, affecting the use of the thermal conductive sheets. Summary of the Invention

[0005] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a method for preparing a diamond-reinforced metal-based composite material with high thermal conductivity, so as to solve one or more problems in the prior art.

[0006] To achieve the above object, the technical solution of the present invention is as follows: A method for preparing a high thermal conductivity diamond-reinforced metal matrix composite material comprises the following steps: S1: Prepare materials: 18-25 parts of diamond powder, 5-8 parts of metal matrix, 6-8 parts of metal catalyst and 3-6 parts of treatment liquid; S2: Diamond powder processing, mixing diamond powder with silicone oil and ball milling, mixing the ball-milled mixed powder with a metal catalyst, sintering at high temperature, and then cooling to room temperature to obtain a polycrystalline diamond composite material; S3: Diamond prefabrication: placing the polycrystalline diamond composite material into a graphite mold and cold pressing to obtain a diamond body. The diamond body and the mold are transferred to a spark plasma sintering furnace and spark plasma sintered under vacuum or inert atmosphere to obtain a diamond preform. S4: metal matrix processing, heating the metal matrix to 300-370°C above the melting point to obtain a molten metal matrix; S5: Diamond soaking: adding the diamond preform in step 2 to the treatment solution and soaking for 5-8 hours to obtain a porous diamond material; S6: Infiltration, under a protective atmosphere, the diamond porous material prepared in step 5 is placed in a mold, and a molten metal matrix is ​​poured onto the diamond porous material in the mold for infiltration. After the molten metal is completely immersed in the diamond porous material, the material is cooled to room temperature and finally demolded to obtain a high thermal conductivity diamond composite material embryo; S7: polishing, polishing the high thermal conductivity diamond composite material embryo after demoulding in step 6 to obtain a high thermal conductivity diamond composite material.

[0007] Furthermore, the particle size of the diamond powder is 5-20 μm, the surface of the diamond powder has a coating, the material of the coating is any one of W, Mo, Cr or Ti, and the thickness of the coating is 10-45 nm.

[0008] On the basis of the above scheme, the high temperature sintering process of the second step is: heating to 750-850° C. at a heating rate of 70-220° C. / min and keeping the temperature for 15-65 minutes.

[0009] As a further solution of the present invention, the cold pressing process in step three is: pressurizing to 6-10 MPa at a pressurizing speed of 5-60 mm / min and maintaining the pressure for 2-5 minutes.

[0010] Furthermore, the spark plasma sintering temperature in step 3 is: heating rate of 55-250℃ / min, sintering temperature of 1100-1550℃, holding time of 10-20min, pulse condition of t on -t off =(2-10):1.

[0011] Based on the above scheme, the method of infiltration of the molten metal matrix in step six is: any one of: melt infiltration, spark plasma sintering, vacuum hot pressing sintering, pressureless infiltration, vacuum gas pressure infiltration or squeeze casting.

[0012] As a further embodiment of the present invention, the metal catalyst is any one of iron, cobalt, nickel, manganese, iron alloy, nickel alloy or cobalt alloy, and the treatment liquid is any one of aqua regia, mixed acid solution, alkali solution and saline solution.

[0013] Furthermore, the metal substrate is any one of copper, aluminum, silver, gold, copper alloy, aluminum alloy or silver alloy, and the inert atmosphere is any one of argon, nitrogen or helium. Compared with the prior art, the beneficial technical effects of the present invention are as follows: (1) The present invention infiltrates a thermally conductive metal into a porous diamond material to form a concrete structure of diamond and thermally conductive metal. This structure not only has thermal conductivity close to that of diamond, but also has a higher density. This makes the high thermal conductivity diamond composite material have higher hardness and thermal conductivity than ordinary diamond copper thermal conductive materials. The hardness is increased by 15-20 times and the thermal conductivity is increased by 2-3 times.

[0014] (2) The present invention utilizes spark plasma sintering to sinter the coating on the surface of the diamond together to form a continuous three-dimensional interconnected network of heat-conducting pathways, thereby improving the thermal conductivity of the prepared composite material. The diamond surface coating is a metal that easily reacts with diamond to form carbides, and the generated carbides do not undergo hydrolysis reactions with water and oxygen and are relatively stable, thereby improving the reliability of the prepared composite material.

[0015] (3) The method of the present invention is low-cost, simple in process, easy to operate, suitable for large-scale preparation, suitable for the preparation of large-block diamond-reinforced metal-based composite materials, easy to realize industrial production and application, and can significantly increase the single-time output, thereby improving production efficiency.

[0016] (IV) The present invention uses silicone oil as raw material and sintering, and the process is simple, easy to operate, and low-cost. It can also achieve the preparation of large-volume diamond preforms or composite materials, meeting the requirements of industrial production and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The schematic diagram of the process structure of the preparation method of the high thermal conductivity diamond reinforced metal matrix composite material of the present invention is shown. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solutions and advantages of the present invention clearer, the device proposed in the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the drawings are in a very simplified form and use non-precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, please refer to the drawings. It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no technical substantive significance. Any structural modification, change in proportional relationship or adjustment of size, without affecting the efficacy and purpose that can be achieved by the present invention, should still fall within the scope of the technical content disclosed by the present invention.

[0019] Example 1 Reference Figure 1 A method for preparing a high thermal conductivity diamond-reinforced metal matrix composite material comprises the following steps: S1: Prepare materials: 25 parts of diamond powder, 8 parts of metal matrix, 8 parts of metal catalyst and 6 parts of treatment liquid; S2: Diamond powder processing, diamond powder is mixed with silicone oil and ball milled, the mixed powder after ball milling is mixed with a metal catalyst, and then sintered at high temperature, and then cooled to room temperature to obtain polycrystalline diamond composite material. The process method is simple, easy to operate, low-cost, and can achieve the preparation of large-volume diamond preforms or composite materials, meeting the requirements of industrial production and application; S3: Diamond prefabrication: placing a polycrystalline diamond composite material into a graphite mold and cold pressing to obtain a diamond blank. The diamond blank and the mold are transferred to a spark plasma sintering furnace and spark plasma sintered under inert atmosphere to obtain a diamond preform. Spark plasma sintering is used to sinter the coating on the diamond surface together to form a continuous three-dimensional interconnected network of heat conduction paths, thereby improving the thermal conductivity of the prepared composite material. The diamond surface coating is a metal that easily reacts with diamond to form carbides, and the generated carbides will not undergo hydrolysis reaction with water and oxygen, and are relatively stable, thereby improving the reliability of the prepared composite material. S4: metal matrix processing, heating the metal matrix to 370°C above the melting point to obtain a molten metal matrix; S5: Diamond soaking: adding the diamond preform prepared in step 2 into the treatment solution and soaking for 8 hours to obtain a porous diamond material; S6: Infiltration. Under a protective atmosphere, the diamond porous material prepared in step 5 is placed in a mold. A molten metal matrix is ​​poured onto the diamond porous material in the mold for infiltration. After the molten metal is completely immersed in the diamond porous material, the material is cooled to room temperature and demolded to obtain a high thermal conductivity diamond composite material embryo. The thermal conductive metal is infiltrated into the diamond porous material to form a concrete structure of diamond and thermal conductive metal. The composite material not only has a thermal conductivity close to that of diamond, but also has a higher density. This makes the high thermal conductivity diamond composite material have higher hardness and thermal conductivity than ordinary diamond copper thermal conductive materials. The hardness is increased by 20 times and the thermal conductivity is increased by 3 times. S7: polishing, polishing the high thermal conductivity diamond composite material embryo after demoulding in step 6 to obtain a high thermal conductivity diamond composite material.

[0020] In the present invention, the particle size of the diamond powder is 20 μm, the surface of the diamond powder has a coating, the material of the coating is Ti, and the coating thickness is 45 nm. The high-temperature sintering process in step 2 is: heating to 850°C at a heating rate of 220°C / min and holding for 65 minutes. The cold pressing process in step 3 is: pressurizing to 6 MPa at a pressing speed of 60 mm / min and holding for 5 minutes. The spark plasma sintering temperature in step 3 is: heating rate of 250°C / min, sintering temperature of 1100°C, holding time of 20 minutes, and pulse condition of t on -t off =10:1; In particular, the method for infiltrating the molten metal matrix in step six is: vacuum hot pressing sintering, the metal catalyst is a cobalt alloy, the treatment liquid is an alkaline solution, the metal matrix is ​​a silver alloy, and the inert atmosphere is nitrogen.

[0021] Example 2 Reference Figure 1 A method for preparing a high thermal conductivity diamond-reinforced metal matrix composite material comprises the following steps: S1: Prepare materials: 20 parts of diamond powder, 6 parts of metal base, 7 parts of metal catalyst and 4 parts of treatment liquid; S2: Diamond powder processing, diamond powder is mixed with silicone oil and ball milled, the mixed powder after ball milling is mixed with a metal catalyst, and then sintered at high temperature, and then cooled to room temperature to obtain polycrystalline diamond composite material. The process method is simple, easy to operate, low-cost, and can achieve the preparation of large-volume diamond preforms or composite materials, meeting the requirements of industrial production and application; S3: Diamond prefabrication: placing a polycrystalline diamond composite material into a graphite mold and cold pressing to obtain a diamond blank. The diamond blank and the mold are transferred to a spark plasma sintering furnace and spark plasma sintered under vacuum protection to obtain a diamond preform. Spark plasma sintering is used to sinter the coating on the diamond surface together to form a continuous three-dimensional interconnected network of heat conduction paths, thereby improving the thermal conductivity of the prepared composite material. The diamond surface coating is a metal that easily reacts with diamond to form carbides. The generated carbides will not undergo hydrolysis reaction with water and oxygen and are relatively stable, thereby improving the reliability of the prepared composite material. S4: metal matrix processing, heating the metal matrix to 350°C above the melting point to obtain a molten metal matrix; S5: Diamond soaking: adding the diamond preform prepared in step 2 into the treatment solution and soaking for 7 hours to obtain a porous diamond material; S6: Infiltration. Under a protective atmosphere, the diamond porous material prepared in step 5 is placed in a mold. A molten metal matrix is ​​poured onto the diamond porous material in the mold for infiltration. After the molten metal is completely immersed in the diamond porous material, the material is cooled to room temperature and demolded to obtain a high thermal conductivity diamond composite material embryo. The thermal conductive metal is infiltrated into the diamond porous material to form a concrete structure of diamond and thermal conductive metal. The composite material not only has a thermal conductivity close to that of diamond, but also has a higher density. This makes the high thermal conductivity diamond composite material have higher hardness and thermal conductivity than ordinary diamond copper thermal conductive materials. The hardness is increased by 16 times and the thermal conductivity is increased by 3 times. S7: polishing, polishing the high thermal conductivity diamond composite material embryo after demoulding in step 6 to obtain a high thermal conductivity diamond composite material.

[0022] In the present invention, the particle size of the diamond powder is 15 μm, the surface of the diamond powder has a coating, the material of the coating is Mo, and the coating thickness is 25 nm. The high-temperature sintering process in step 2 is: heating to 800°C at a heating rate of 135°C / min and holding for 45 minutes. The cold pressing process in step 3 is: pressurizing to 8 MPa at a pressing speed of 25 mm / min and holding for 4 minutes. The spark plasma sintering temperature in step 3 is: heating rate of 150°C / min, sintering temperature of 1350°C, holding time of 15 minutes, and pulse condition of t on -t off =8:1; In particular, the method for infiltrating the molten metal matrix in step six is: vacuum pressure infiltration, the metal catalyst is an iron alloy, the treatment liquid is a mixed acid solution, and the metal matrix is ​​a copper alloy.

[0023] Example 3 Reference Figure 1 A method for preparing a high thermal conductivity diamond-reinforced metal matrix composite material comprises the following steps: S1: Prepare materials: 18 parts of diamond powder, 5 parts of metal matrix, 6 parts of metal catalyst and 3 parts of treatment liquid; S2: Diamond powder processing, diamond powder is mixed with silicone oil and ball milled, the mixed powder after ball milling is mixed with a metal catalyst, and then sintered at high temperature, and then cooled to room temperature to obtain polycrystalline diamond composite material. The process method is simple, easy to operate, low-cost, and can achieve the preparation of large-volume diamond preforms or composite materials, meeting the requirements of industrial production and application; S3: Diamond prefabrication: placing a polycrystalline diamond composite material into a graphite mold and cold pressing to obtain a diamond blank. The diamond blank and the mold are transferred to a spark plasma sintering furnace and spark plasma sintered under inert atmosphere to obtain a diamond preform. Spark plasma sintering is used to sinter the coating on the diamond surface together to form a continuous three-dimensional interconnected network of heat conduction paths, thereby improving the thermal conductivity of the prepared composite material. The diamond surface coating is a metal that easily reacts with diamond to form carbides, and the generated carbides will not undergo hydrolysis reaction with water and oxygen, and are relatively stable, thereby improving the reliability of the prepared composite material. S4: metal matrix processing, heating the metal matrix to 300°C above the melting point to obtain a molten metal matrix; S5: Diamond soaking: adding the diamond preform prepared in step 2 into the treatment solution and soaking for 5 hours to obtain a porous diamond material; S6: Infiltration. Under a protective atmosphere, the diamond porous material prepared in step 5 is placed in a mold. A molten metal matrix is ​​poured onto the diamond porous material in the mold for infiltration. After the molten metal is completely immersed in the diamond porous material, the material is cooled to room temperature and demolded to obtain a high thermal conductivity diamond composite material embryo. The thermal conductive metal is infiltrated into the diamond porous material to form a concrete structure of diamond and thermal conductive metal. The composite material not only has a thermal conductivity close to that of diamond, but also has a higher density. This makes the high thermal conductivity diamond composite material have higher hardness and thermal conductivity than ordinary diamond copper thermal conductive materials. The hardness is increased by 15 times and the thermal conductivity is increased by 2 times. S7: polishing, polishing the high thermal conductivity diamond composite material embryo after demoulding in step 6 to obtain a high thermal conductivity diamond composite material.

[0024] In the present invention, the particle size of the diamond powder is 5 μm, the surface of the diamond powder has a coating, the material of the coating is W, and the coating thickness is 10 nm. The high-temperature sintering process in step 2 is: heating to 850°C at a heating rate of 70°C / min and holding for 15 minutes. The cold pressing process in step 3 is: pressurizing to 10 MPa at a pressing speed of 5 mm / min and holding for 2 minutes. The spark plasma sintering temperature in step 3 is: heating rate of 55°C / min, sintering temperature of 1550°C, holding time of 10 minutes, and pulse condition of t on -t off =2:1; In particular, the method for infiltrating the molten metal matrix in step six is: pressureless infiltration, the metal catalyst is iron, the treatment liquid is aqua regia, the metal matrix is ​​copper, and the inert atmosphere is argon.

[0025] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0026] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A method for preparing a high thermal conductivity diamond-reinforced metal matrix composite material, characterized in that: The following steps are involved: S1: Prepare materials: 18-25 parts of diamond powder, 5-8 parts of metal matrix, 6-8 parts of metal catalyst and 3-6 parts of treatment liquid; S2: Diamond powder processing, mixing diamond powder with silicone oil and ball milling, mixing the ball-milled mixed powder with a metal catalyst, sintering at high temperature, and then cooling to room temperature to obtain a polycrystalline diamond composite material; S3: Diamond prefabrication: placing the polycrystalline diamond composite material into a graphite mold and cold pressing to obtain a diamond body. The diamond body and the mold are transferred to a spark plasma sintering furnace and spark plasma sintered under vacuum or inert atmosphere to obtain a diamond preform. S4: metal matrix processing, heating the metal matrix to 300-370°C above the melting point to obtain a molten metal matrix; S5: Diamond soaking: adding the diamond preform in step 2 to the treatment solution and soaking for 5-8 hours to obtain a porous diamond material; S6: Infiltration, under a protective atmosphere, the diamond porous material prepared in step 5 is placed in a mold, and a molten metal matrix is ​​poured onto the diamond porous material in the mold for infiltration. After the molten metal is completely immersed in the diamond porous material, the material is cooled to room temperature and finally demolded to obtain a high thermal conductivity diamond composite material embryo; S7: polishing, polishing the high thermal conductivity diamond composite material embryo after demoulding in step 6 to obtain a high thermal conductivity diamond composite material.

2. The method for preparing a high thermal conductivity diamond-reinforced metal matrix composite material according to claim 1, characterized in that: The particle size of the diamond powder is 5-20 μm. The surface of the diamond powder is provided with a coating. The material of the coating is any one of W, Mo, Cr or Ti. The thickness of the coating is 10-45 nm.

3. The method for preparing a high thermal conductivity diamond-reinforced metal matrix composite material according to claim 1, characterized in that: The high temperature sintering process in the second step is: heating to 750-850° C. at a heating rate of 70-220° C. / min and keeping the temperature for 15-65 minutes.

4. The method for preparing a high thermal conductivity diamond-reinforced metal matrix composite material according to claim 1, wherein: The cold pressing process in step 3 is: pressing to 6-10 MPa at a pressing speed of 5-60 mm / min and maintaining the pressure for 2-5 minutes.

5. The method for preparing a high thermal conductivity diamond-reinforced metal matrix composite material according to claim 4, characterized in that: The spark plasma sintering temperature in step 3 is: heating rate of 55-250℃ / min, sintering temperature of 1100-1550℃, holding time of 10-20min, pulse condition of t on -t off =(2-10):

1.

6. The method for preparing a high thermal conductivity diamond-reinforced metal matrix composite material according to claim 1, characterized in that: The method of infiltrating the molten metal matrix in step six is ​​any one of: melt infiltration, spark plasma sintering, vacuum hot pressing sintering, pressureless infiltration, vacuum gas pressure infiltration or squeeze casting.

7. The method for preparing a high thermal conductivity diamond-reinforced metal matrix composite material according to claim 1, wherein: The metal catalyst is any one of iron, cobalt, nickel, manganese, iron alloy, nickel alloy or cobalt alloy, and the treatment liquid is any one of aqua regia, mixed acid solution, alkali solution and saline solution.

8. The method for preparing a high thermal conductivity diamond-reinforced metal matrix composite material according to claim 7, characterized in that: The metal matrix is ​​any one of copper, aluminum, silver, gold, copper alloy, aluminum alloy or silver alloy, and the inert atmosphere is any one of argon, nitrogen or helium.

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