Preparation method capable of preparing special-shaped diamond-copper-tungsten composite material

Abstract

The invention provides a preparation method capable of preparing a special-shaped diamond-copper-tungsten composite material, which comprises the following steps: mixing metal tungsten powder and an organic binder, granulating, and injecting into a special-shaped mold to obtain a shell green body; degumming and sintering the shell green body to obtain a first tungsten skeleton shell with a porous structure; filling the first tungsten skeleton shell with a porous structure with the diamond powder coated with the metal tungsten to obtain a second tungsten skeleton shell; and the second tungsten framework shell is placed in a mold, metal copper is placed on the surface of the second tungsten framework shell for vacuum infiltration, and the diamond-copper-tungsten composite material is obtained. According to the preparation method, various special-shaped parts can be directly prepared while the dimensional precision of the product is guaranteed, the finished product can be obtained only by performing fine treatment on the surface, the machining amount is reduced, and the effects of reducing cost and improving efficiency are achieved.

Description

Technical Field

[0001] The invention belongs to the field of heat sink materials, and relates to a method for preparing a diamond-copper-tungsten composite material, and in particular to a method for preparing a special-shaped diamond-copper-tungsten composite material. Background Art

[0002] With the rapid development of integrated circuits, chips, optical modules and other industries, and the increase in power density, higher heat dissipation requirements have been put forward for their supporting packaging heat dissipation materials. The thermal conductivity of traditional heat dissipation materials is generally difficult to exceed 200W / (m·K), and the thermal expansion coefficient does not match that of semiconductor power devices, which can no longer meet the heat dissipation requirements.

[0003] Diamond has a thermal conductivity of up to 1200-2000 W / (m·K) and a thermal conductivity of 1.2×10 -6 The low thermal expansion coefficient of the material can be mixed with metal materials to obtain a variety of high thermal conductivity and low thermal expansion composite materials by adjusting the composition and proportion.

[0004] Conventional preparation methods for diamond-copper composite materials are divided into solid phase molding method and liquid phase molding method. The basic principle is to mix diamond and copper powder and then sinter them, or mix diamond and molten copper and then cool them. However, these processing methods can basically only produce slabs with simple shapes, and diamonds are easy to leak out of the surface of the billet. Subsequent finishing will bring high processing difficulty due to the presence of surface diamonds. Summary of the invention

[0005] In order to solve the above technical problems, the present application provides a preparation method for preparing special-shaped diamond-copper-tungsten composite materials. This preparation method can directly prepare various special-shaped parts while ensuring the dimensional accuracy of the product. The finished product can be obtained by only finely processing the surface, reducing the processing amount and achieving the effect of reducing costs and increasing efficiency.

[0006] In order to achieve the above technical effects, the present invention adopts the following technical solutions:

[0007] The present invention provides a method for preparing a special-shaped diamond-copper-tungsten composite material, and the preparation method comprises:

[0008] The metal tungsten powder is mixed with an organic binder to form granules and then injected into a special-shaped mold to obtain a shell green body;

[0009] Debonding and sintering the shell green body to obtain a first tungsten skeleton shell with a porous structure;

[0010] Filling diamond powder coated with metal tungsten into a first tungsten skeleton shell having a porous structure to obtain a second tungsten skeleton shell;

[0011] The second tungsten skeleton shell is placed in a mold, and metal copper is placed on the surface of the second tungsten skeleton shell for vacuum infiltration to obtain a diamond-copper-tungsten composite material.

[0012] As a preferred technical solution of the present invention, the mass proportion of tungsten powder in mixed granulation is 60-80%.

[0013] As a preferred technical solution of the present invention, the particle size of the tungsten powder is 1 to 5 μm.

[0014] As a preferred technical solution of the present invention, the sintering temperature is 900-1100° C. and the sintering time is 1-4 hours.

[0015] As a preferred technical solution of the present invention, the particle size of the diamond powder is 300 to 1000 μm.

[0016] As a preferred technical solution of the present invention, the thickness of the metal tungsten coating layer of the diamond powder is 100-200 nm.

[0017] As a preferred technical solution of the present invention, the diamond powder is compacted using ultrasound after filling.

[0018] As a preferred technical solution of the present invention, the volume proportion of diamond in the second tungsten skeleton shell is 50-70%.

[0019] As a preferred technical solution of the present invention, the temperature of vacuum infiltration is 1100-1400° C. and the time is 1-2 hours.

[0020] As a preferred technical solution of the present invention, after vacuum infiltration, the surface of the diamond-copper-tungsten composite material is finely processed to remove excess metal copper.

[0021] Compared with the prior art, the present invention has at least the following beneficial effects:

[0022] (1) The present invention provides a method for preparing a special-shaped diamond-copper-tungsten composite material, which can significantly reduce the production difficulty and improve the efficiency while ensuring the dimensional accuracy of the product.

[0023] (2) The present invention provides a method for preparing a special-shaped diamond-copper-tungsten composite material. The method can directly prepare various special-shaped parts. The finished product can be obtained by only finely processing the surface, thereby reducing the processing amount and achieving the effect of reducing costs and increasing efficiency.

[0024] (3) The present invention provides a method for preparing a special-shaped diamond-copper-tungsten composite material. The diamond-copper-tungsten composite material prepared by the preparation method has excellent electrical conductivity, as well as anti-seismic and anti-deformation capabilities. DETAILED DESCRIPTION

[0025] The technical solution of the present invention is further described below through specific implementation methods.

[0026] A specific embodiment of the present invention provides a method for preparing a special-shaped diamond-copper-tungsten composite material, and the preparation method comprises:

[0027] The metal tungsten powder is mixed with an organic binder to form granules and then injected into a special-shaped mold to obtain a shell green body;

[0028] Debonding and sintering the shell green body to obtain a first tungsten skeleton shell with a porous structure;

[0029] Filling diamond powder coated with metal tungsten into a first tungsten skeleton shell having a porous structure to obtain a second tungsten skeleton shell;

[0030] The second tungsten skeleton shell is placed in a mold, and metal copper is placed on the surface of the second tungsten skeleton shell for vacuum infiltration to obtain a diamond-copper-tungsten composite material.

[0031] In the present invention, the diamond can be confined to a specific area by using the tungsten skeleton shell as a support, saving materials and avoiding unnecessary waste; tungsten and copper have good wettability at high temperature, and during infiltration, the copper liquid can penetrate inward well after melting until the inner cavity of the tungsten skeleton is completely filled, and it is also tightly combined with the tungsten-plated diamond powder to form a dense composite material; tungsten has a high melting point and is not easy to deform after pre-sintering. The size after sintering is basically the same as the size of the finished product. Only the excess copper on the overall surface needs to be processed, and the processing is simple; after the infiltration is completed, a tungsten-copper layer is formed on the outer layer of the shell, and the electroplating process is simpler than direct diamond-copper plating. In a specific embodiment of the present invention, the mass proportion of tungsten powder in the mixed granulation is 60-80%, such as 60%, 62%, 65%, 68%, 70%, 72%, 75%, 78% or 80%, etc., but it is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0032] In a specific embodiment of the present invention, the particle size of the tungsten powder is 1 to 5 μm, such as 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm or 5 μm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0033] In a specific embodiment of the present invention, the composition of the organic binder may include 1 to 5 wt % of stearic acid, 20 to 50 wt % of paraffin wax and 45 to 79 wt % of polypropylene.

[0034] In one specific embodiment of the present invention, an injection molding machine may be used to injection mold the granules into a mold.

[0035] In a specific embodiment of the present invention, the shell green body is pre-reserved with powder filling holes.

[0036] In a specific embodiment of the present invention, the shell green body is subjected to degumming treatment, and the degumming treatment conditions are conventional conditions for degumming treatment in the art and are not specifically limited here. The volume of the through holes of the tungsten skeleton obtained after the degumming treatment accounts for 10-30%.

[0037] In a specific embodiment of the present invention, the sintering temperature is 900-1100°C and the time is 1-4 hours. The temperature may be 900°C, 950°C, 1000°C, 1050°C and 1100°C, and the time may be 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours or 4 hours, but is not limited to the listed values. Other values ​​not listed within the above ranges are also applicable.

[0038] In a specific embodiment of the present invention, diamond powder coated with metal tungsten is filled into a first tungsten skeleton shell having a porous structure, and is subjected to a densification treatment using ultrasound. The frequency and time of the ultrasound treatment can be selected according to the volume of the diamond powder added and the processing requirements, and are not specifically limited here.

[0039] In a specific embodiment of the present invention, the mold used for vacuum infiltration can be a graphite grinder.

[0040] In one specific embodiment of the present invention, vacuum infiltration can be performed in a vacuum furnace.

[0041] In a specific embodiment of the present invention, the metallic copper is preferably a TU1 copper plate.

[0042] In a specific embodiment of the present invention, the temperature of vacuum infiltration is 1100-1400°C, and the time is 1-2h. The temperature may be 1100°C, 1150°C, 1200°C, 1250°C, 1300°C, 1350°C, 1400°C, 1450°C or 1500°C, and the time may be 1h, 1.2h, 1.5h, 1.8h or 2h, but is not limited to the listed values, and other values ​​not listed within the above ranges are also applicable.

[0043] In a specific embodiment of the present invention, after vacuum infiltration, the surface of the diamond-copper-tungsten composite material is finely processed by CNC to remove excess metallic copper.

[0044] In a specific embodiment of the present invention, the shell component of the diamond-copper-tungsten composite material is tungsten (10-25wt%) copper alloy, and the content is a composite material of diamond (50-65wt%) copper.

[0045] For the convenience of understanding the present invention, the present invention lists the following embodiments. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0046] Example 1

[0047] This embodiment provides a method for preparing a special-shaped diamond-copper-tungsten composite material, and the preparation method comprises:

[0048] Metal tungsten powder (particle size of 3-5 μm, mass proportion of 80 wt%) and organic binder (5 wt% stearic acid, 35 wt% paraffin, 60 wt% polypropylene) are mixed and granulated and then injection molded into a tubular bottom mold to obtain a shell green body;

[0049] The shell green body is debonded, and the volume of the through holes of the obtained tungsten skeleton accounts for 20%; sintering is performed at a temperature of 980° C. for 2 hours to obtain a first tungsten skeleton shell with a porous structure;

[0050] Diamond powder coated with metal tungsten (particle size 200 μm, coating layer thickness 150 nm) is filled into a first tungsten skeleton shell having a porous structure, and ultrasonically compacted to obtain a second tungsten skeleton shell in which the volume proportion of diamond is 45%;

[0051] The second tungsten skeleton shell was placed in a contoured graphite mold and transferred to a vacuum furnace. The TU1 copper plate was placed on the surface of the second tungsten skeleton shell for vacuum infiltration at a temperature of 1400°C for 2 hours to obtain a diamond-copper-tungsten composite material.

[0052] After vacuum infiltration, the surface of the diamond-copper-tungsten composite material is finely processed by CNC to remove excess metal copper, thereby obtaining a tungsten-copper alloy with a shell thickness of 0.5 mm and a diamond-copper composite material as the content.

[0053] Example 2

[0054] This embodiment provides a method for preparing a special-shaped diamond-copper-tungsten composite material, and the preparation method comprises:

[0055] Metal tungsten powder (particle size of 1-3 μm, mass proportion of 60 wt%) and organic binder (1 wt% stearic acid, 20 wt% paraffin, 79 wt% polypropylene) are mixed and granulated, and then injection molded into a tubular bottom mold to obtain a shell green body;

[0056] The shell green body is debonded, and the volume of the through holes of the obtained tungsten skeleton accounts for 10%; sintering is performed at a temperature of 900° C. for 4 hours to obtain a first tungsten skeleton shell with a porous structure;

[0057] Diamond powder coated with metal tungsten (particle size 200 μm, coating layer thickness 100 nm) is filled into a first tungsten skeleton shell having a porous structure, and ultrasonically compacted to obtain a second tungsten skeleton shell in which the volume proportion of diamond is 50%;

[0058] The second tungsten skeleton shell was placed in a contoured graphite mold and transferred to a vacuum furnace. The TU1 copper plate was placed on the surface of the second tungsten skeleton shell for vacuum infiltration at a temperature of 1100°C for 2 hours to obtain a diamond-copper-tungsten composite material.

[0059] After vacuum infiltration, the surface of the diamond-copper-tungsten composite material is finely processed by CNC to remove excess metal copper, thereby obtaining a composite material with a tungsten-copper alloy shell and a diamond-copper content.

[0060] Example 3

[0061] This embodiment provides a method for preparing a special-shaped diamond-copper-tungsten composite material, and the preparation method comprises:

[0062] Metal tungsten powder (particle size of 2-4 μm, mass proportion of 70 wt%) and organic binder (5 wt% stearic acid, 50 wt% paraffin, 45 wt% polypropylene) are mixed and granulated and then injection molded into a tubular bottom mold to obtain a shell green body;

[0063] The shell green body is debonded, and the volume of the through holes of the obtained tungsten skeleton accounts for 20%; sintering is performed at a temperature of 1100° C. for 1 hour to obtain a first tungsten skeleton shell with a porous structure;

[0064] Diamond powder coated with metal tungsten (particle size 1000 μm, coating layer thickness 200 nm) is filled into a first tungsten skeleton shell having a porous structure, and ultrasonically compacted to obtain a second tungsten skeleton shell with a volume percentage of 55% of diamond;

[0065] The second tungsten skeleton shell was placed in a contoured graphite mold and transferred to a vacuum furnace. The TU1 copper plate was placed on the surface of the second tungsten skeleton shell for vacuum infiltration at a temperature of 1200°C for 1.5 hours to obtain a diamond-copper-tungsten composite material.

[0066] After vacuum infiltration, the surface of the diamond-copper-tungsten composite material is finely processed by CNC to remove excess metal copper, thereby obtaining a composite material with a tungsten-copper alloy shell and a diamond-copper content.

[0067] Example 4

[0068] This embodiment provides a method for preparing a special-shaped diamond-copper-tungsten composite material, and the preparation method comprises:

[0069] Metal tungsten powder (particle size of 2-4 μm, mass proportion of 65 wt%) and organic binder (3 wt% stearic acid, 37 wt% paraffin, 60 wt% polypropylene) are mixed and granulated and then injection molded into a tubular bottom mold to obtain a shell green body;

[0070] The shell green body is debonded, and the volume of the through holes of the obtained tungsten skeleton accounts for 30%; the shell is sintered at a temperature of 1100° C. for 1 hour to obtain a first tungsten skeleton shell with a porous structure;

[0071] Diamond powder coated with metal tungsten (particle size 300 μm, coating layer thickness 120 nm) is filled into a first tungsten skeleton shell having a porous structure, and ultrasonically compacted to obtain a second tungsten skeleton shell in which the volume proportion of diamond is 60%;

[0072] The second tungsten skeleton shell was placed in a contoured graphite mold and transferred to a vacuum furnace. The TU1 copper plate was placed on the surface of the second tungsten skeleton shell for vacuum infiltration at a temperature of 1200°C for 1.5 hours to obtain a diamond-copper-tungsten composite material.

[0073] After vacuum infiltration, the surface of the diamond-copper-tungsten composite material is finely processed by CNC to remove excess metal copper, thereby obtaining a composite material with a tungsten-copper alloy shell and a diamond-copper content.

[0074] Example 5

[0075] In this embodiment, except that the tubular bottom mold is replaced with a mold with a round cake, a square, a special-shaped boss, etc., the other conditions are the same as those in Example 1. In order to ensure that the tungsten copper of the shell fully wraps the contents (surface consistency) and reduce the difficulty of injection molding of the shell, the shell needs to be divided into two parts, one part is a main shell structure with concave and convex shapes (the concave and convex direction is consistent with the demoulding direction after injection molding), and the other part is used as a cover after filling with powder (filled with powder and then covered and vacuum infiltrated, and small holes can even be opened on the cover as supplementary powder filling holes for filling and compaction after ultrasonic vibration).

[0076] Comparative Example 1

[0077] In this comparative example, except that tungsten is replaced by molybdenum, the other conditions are the same as those of Example 1.

[0078] Comparative Example 2

[0079] In this comparative example, except that the diamond surface is not coated with metal tungsten, other conditions are the same as those of Example 1.

[0080] Comparative Example 3

[0081] In this comparative example, except that the tungsten-coated diamond powder and metallic copper are directly placed in a contoured graphite mold (ie, a tungsten skeleton shell is not prepared), the other conditions are the same as those of Example 1.

[0082] The thermal conductivity, thermal expansion coefficient and deformation resistance of the diamond-copper-tungsten composite materials prepared in Examples 1-5 and Comparative Examples 1-3 were tested, and the results are shown in Table 1.

[0083] The test method for thermal conductivity is GB / T 22588.

[0084] The test method for thermal expansion coefficient is GB / T 4339.

[0085] The test method for deformation resistance is GB / T 232-2024.

[0086] Table 1

[0087]

[0088] It can be seen from the test results in Table 1 that the shell prepared by the preparation method for preparing a special-shaped diamond-copper-tungsten composite material provided in Examples 1-5 of the present invention is a tungsten-copper alloy, and the composite material containing diamond-copper has excellent electrical conductivity, shock resistance and deformation resistance. In Comparative Example 1, compared with Example 1, tungsten is replaced with molybdenum to prepare the shell, resulting in an increase in the thermal expansion coefficient of the composite material and a decrease in the deformation resistance; in Comparative Example 2, compared with Example 1, the surface of the diamond powder is not coated with metal tungsten, resulting in a significant decrease in the thermal conductivity of the composite material; in Comparative Example 3, compared with Example 1, no tungsten skeleton is prepared, resulting in a significant decrease in the deformation resistance of the material.

[0089] The applicant declares that the present invention illustrates the detailed process equipment and process flow of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed process equipment and process flow, that is, it does not mean that the present invention must rely on the above-mentioned detailed process equipment and process flow to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a special-shaped diamond-copper-tungsten composite material, characterized in that: The preparation method comprises: The metal tungsten powder is mixed with an organic binder to form granules and then injected into a special-shaped mold to obtain a shell green body; Debonding and sintering the shell green body to obtain a first tungsten skeleton shell with a porous structure; Filling diamond powder coated with metal tungsten into the first tungsten skeleton shell having a porous structure to obtain a second tungsten skeleton shell; The second tungsten skeleton shell is placed in a mold, and metal copper is placed on the surface of the second tungsten skeleton shell for vacuum infiltration to obtain the diamond-copper-tungsten composite material.

2. The preparation method according to claim 1, characterized in that: The mass proportion of tungsten powder in the mixed granulation is 60-80%.

3. The preparation method according to claim 1, characterized in that: The particle size of the tungsten powder is 1-5 μm.

4. The preparation method according to claim 1, characterized in that: The sintering process is carried out at a temperature of 900 to 1100° C. and for a time of 1 to 4 hours.

5. The preparation method according to claim 1, characterized in that: The particle size of the diamond powder is 300-1000 μm.

6. The preparation method according to claim 1, characterized in that: The thickness of the metal tungsten coating layer of the diamond powder is 100-200 nm.

7. The preparation method according to claim 1, characterized in that: The diamond powder is compacted using ultrasound after filling.

8. The preparation method according to claim 1, characterized in that: The volume proportion of diamond in the second tungsten skeleton shell is 50-70%.

9. The preparation method according to claim 1, characterized in that: The vacuum infiltration temperature is 1100-1400° C. and the time is 1-2 hours.

10. The preparation method according to claim 1, characterized in that: After the vacuum infiltration, the surface of the diamond-copper-tungsten composite material is finely processed to remove excess metal copper.

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