A sheet-shaped metal-based diamond composite material, a method for preparing the same, and an application thereof

Abstract

The present application belongs to the technical field of heat-conducting materials, and particularly relates to a sheet-shaped metal-based diamond composite material, a preparation method and application thereof. The sheet-shaped metal-based diamond composite material comprises a diamond composite material layer; the diamond composite material layer comprises diamond particles, a reinforcing phase and a binder; in the diamond composite material layer, the diamond particles are distributed in a single layer; the reinforcing phase and the binder fill the gaps between the single-layer distributed diamond particles; the reinforcing phase comprises at least one of carbon fibers, flake graphite, carbon nanotubes, graphene and graphene oxide; and the binder comprises a metal-based binder. The single-layer distributed diamond particles can form a rapid heat-conducting channel, the binder consolidates the diamond particles, reduces the hindering of pores to heat conduction, the reinforcing phase fills the gaps between the diamond particles, builds a rapid heat-conducting channel, and the three jointly act to improve the thermal conductivity of the composite material, reduce the thermal expansion coefficient, and improve the mechanical properties and reliability.

Description

Technical Field

[0001] This invention belongs to the field of thermal conductive materials technology, and specifically relates to a sheet-like metal-based diamond composite material, its preparation method, and its application. Background Technology

[0002] With the rapid development of electronic devices towards miniaturization, integration, lightweighting, intelligence, and multifunctionality, heat flux density is increasing dramatically. This rapid increase in heat can damage electronic devices, posing a potential threat to their lifespan, stability, and reliability. To ensure the normal operation and lifespan of electronic devices, higher requirements are placed on heat dissipation materials. Diamond is the material with the highest thermal conductivity in nature (1500-2400 W / (m·K)) and possesses excellent properties such as extremely high hardness, good chemical stability, and a low coefficient of thermal expansion. However, due to the high cost of diamond sheet preparation and the slow growth rate of single-crystal diamond, it is difficult to prepare large-size single-crystal diamond sheets. Furthermore, the thermal conductivity of current heat dissipation materials still cannot meet the needs of practical applications.

[0003] Therefore, there is an urgent need to provide a composite material with good thermal conductivity and mechanical properties, which can meet the application requirements of large size and thin thickness, and can achieve near-net-shape forming with less subsequent processing and low manufacturing cost. Summary of the Invention

[0004] This invention aims to solve one or more technical problems existing in the prior art, and at least provide a beneficial alternative or create conditions. This invention provides a sheet-like metal-based diamond composite material, which has good thermal conductivity and mechanical properties, can meet the needs of large-size applications, and can achieve near-net-shape forming with minimal subsequent processing and low manufacturing cost.

[0005] The inventive concept of this invention is as follows: This invention uses high thermal conductivity diamond particles combined with a metal-based binder. The diamond in the composite material can form rapid heat transfer channels, allowing heat generated by electronic devices to be quickly conducted to the external environment. The metal binder serves to solidify the diamond particles, densifying the material and reducing the obstruction of heat conduction by pores. Furthermore, diamonds are mostly hexahedral, octahedral, and tetrahedral, and a two-dimensional network structure of voids is formed between monolayered diamonds. Therefore, a reinforcing phase with high thermal conductivity is used to fill the voids between diamond particles, creating rapid heat conduction channels within these voids. The combined effect of the monolayered diamond, reinforcing phase, and binder improves the thermal conductivity of the composite material, reduces the coefficient of thermal expansion, and enhances mechanical properties and reliability, meeting the heat dissipation application requirements of high thermal conductivity, high mechanical properties, large size, thin thickness, and high reliability.

[0006] Therefore, a first aspect of the present invention provides a sheet-like metal-based diamond composite material.

[0007] Specifically, a sheet-like metal-based diamond composite material includes a diamond composite layer; the diamond composite layer includes diamond particles, a reinforcing phase, and a binder; in the diamond composite layer, the diamond particles are distributed in a single layer; the reinforcing phase and the binder fill the gaps between the single-layer distributed diamond particles;

[0008] The reinforcing phase includes at least one of carbon fiber, flake graphite, carbon nanotubes, graphene, and graphene oxide.

[0009] The binder includes a metal-based binder.

[0010] Preferably, the diamond particles are distributed in a single layer of close-packed arrangement.

[0011] Preferably, the diamond particles include at least one of unmodified diamond particles and surface-modified diamond particles; the surface-modified diamond particles include at least one of surface-roughened diamond particles and surface-coated diamond particles.

[0012] Preferably, the surface-coated diamond particles include at least one of surface-coated single-layer diamond particles and surface-coated composite-layer diamond particles.

[0013] Preferably, the coating of the single-layer diamond particles on the surface includes a carbide-forming element; the carbide-forming element is selected from at least one of Cr, Ti, W, B, Zr, and Mo.

[0014] Preferably, the coating of the diamond particles with the surface-coated composite layer includes a carbide-forming element and a matrix element; the carbide-forming element is selected from at least one of Cr, Ti, W, B, Zr, and Mo; and the matrix element is copper.

[0015] Specifically, surface modification of diamond particles improves the interfacial bonding between diamond particles and the binder, forming a continuous and dense interfacial carbide layer at the interface. Due to the poor wettability of diamond particles and the binder, gaps easily form at the interface during preparation, hindering heat transfer. The dense interfacial carbide layer effectively improves the thermal conductivity of the composite material.

[0016] Preferably, the diamond particles have a particle size of 45-1200 μm; more preferably, the diamond particles have a particle size of 50-1200 μm.

[0017] Preferably, the particle size of the reinforcing phase is 0.9 nm-750 μm; more preferably, the particle size of the reinforcing phase is 1 nm-700 μm.

[0018] Preferably, the metal-based binder includes a copper-based binder.

[0019] Preferably, the copper-based binder comprises elemental copper.

[0020] Specifically, an electroplating process is used to fill the gaps between diamond particles and the reinforcing phase with copper binder.

[0021] Preferably, the diamond particles account for 27-65% of the volume fraction of the sheet-like metal-based diamond composite material; the reinforcing phase accounts for 9-45% of the volume fraction of the sheet-like metal-based diamond composite material; and the binder accounts for 18-45% of the volume fraction of the sheet-like metal-based diamond composite material.

[0022] More preferably, the diamond particles account for 30-60% of the volume fraction of the sheet-like metal-based diamond composite material; the reinforcing phase accounts for 10-40% of the volume fraction of the sheet-like metal-based diamond composite material; and the binder accounts for 20-40% of the volume fraction of the sheet-like metal-based diamond composite material.

[0023] Preferably, the sheet-like metal-based diamond composite material further includes a metal coating, which is located on the upper and lower surfaces of the diamond composite material layer.

[0024] Preferably, the metal plating layer is a copper layer.

[0025] A second aspect of the present invention provides a method for preparing the sheet-like metal-based diamond composite material described in the first aspect of the present invention.

[0026] Specifically, the preparation method of the sheet-like metal-based diamond composite material includes the following steps:

[0027] The diamond particles are distributed in a single layer and placed on a cathode substrate. The reinforcing phase and electroplating solution are mixed, and a copper-based material is used as the anode to obtain the sheet-like metal-based diamond composite material by electroplating.

[0028] The electroplating solution is a binder precursor solution.

[0029] Preferably, the copper-based material is selected from either phosphor bronze plate or copper plate.

[0030] Preferably, the amount of the reinforcing phase is 4.5-22 g / L; more preferably, the amount of the reinforcing phase is 5-20 g / L.

[0031] Specifically, the amount of the reinforcing phase is based on the volume of the electroplating solution.

[0032] Preferably, the electroplating solution includes copper salt, chloride-containing compound, brightener, leveling agent, inhibitor and solvent.

[0033] Preferably, the copper salt includes at least one of copper-based acidic sulfate and copper methanesulfonate.

[0034] Preferably, the amount of copper salt used is 45-130 g / L; more preferably, the amount of copper salt used is 50-120 g / L.

[0035] Preferably, the chloride-containing compound includes at least one of hydrochloric acid and sodium chloride.

[0036] Preferably, the amount of the chloride-containing compound is 0.045-0.16 g / L; more preferably, the amount of the chloride-containing compound is 0.05-0.15 g / L.

[0037] Preferably, the brightener includes at least one of polydisulfide compounds and thiourea derivatives.

[0038] Preferably, the amount of brightener used is 0.09-1.1 mL / L; more preferably, the amount of brightener used is 0.1-1 mL / L.

[0039] Preferably, the leveling agent comprises at least one of hexadecyltrimethylammonium bromide and polyethyleneimine alkyl salt.

[0040] Preferably, the amount of the leveling agent is 0.09-1.1 mL / L; more preferably, the amount of the leveling agent is 0.1-1 mL / L.

[0041] Preferably, the inhibitor comprises at least one of polyethylene glycol, polypropylene glycol, and a copolymer of propyl oxide and ethyl oxide.

[0042] Preferably, the amount of the inhibitor is 0.9-11 mL / L; more preferably, the amount of the inhibitor is 1-10 mL / L.

[0043] Preferably, the solvent is water; more preferably, the solvent is deionized water.

[0044] Specifically, in the electroplating solution, the amount of each component is based on the volume of the solvent.

[0045] Specifically, after the reinforcing phase and the electroplating solution are mixed and stirred, the reinforcing phase settles into the gaps between the closely packed diamonds under the action of gravity.

[0046] Preferably, the stirring is magnetic stirring.

[0047] Preferably, the stirring speed is 45-550 rpm; more preferably, the stirring speed is 50-500 rpm.

[0048] Preferably, the current density during electroplating is 4.5-220 A / dm². 2 More preferably, the current density during electroplating is 5-200 A / dm³. 2 .

[0049] Preferably, the electroplating is performed at room temperature.

[0050] Specifically, under the influence of electric current, a reduction reaction occurs at the cathode to generate elemental copper, which is then deposited along with the reinforcing agent to fill the gaps between the single-layer diamond particles.

[0051] Specifically, after observing that elemental copper completely covered the single layer of diamond, the power was turned off, resulting in a dense structure.

[0052] Preferably, the electroplating process further includes surface plating and polishing after electroplating.

[0053] Preferably, the surface coating is to coat the upper and lower surfaces of the sheet-like metal-based diamond composite material layer with a metal layer.

[0054] Preferably, the thickness of the metal layer is 45-550 μm; more preferably, the thickness of the metal layer is 50-500 μm.

[0055] Preferably, the metal layer is a copper layer.

[0056] Specifically, the purpose of copper plating on the upper and lower surfaces of the diamond composite material layer is to improve the welding performance of the composite material to electronic components during the packaging process.

[0057] Specifically, the electroplating solution and electroplating process parameters used when plating the metal layer are the same as above.

[0058] Preferably, the process of plating the metal layer further includes polishing the surface of the metal layer.

[0059] Preferably, the polishing is performed using a polishing machine.

[0060] Preferably, the sandpaper used for polishing is silicon carbide sandpaper; the mesh size of the sandpaper is 1500-5000.

[0061] Preferably, the polishing speed is 90-1100 rpm; more preferably, the polishing speed is 100-1000 rpm.

[0062] Preferably, the polishing pressure is 9-110N; more preferably, the polishing pressure is 10-100N.

[0063] Preferably, after polishing, the surface roughness of the metal layer is 0.09-11 μm; more preferably, the surface roughness of the metal layer is 0.1-10 μm.

[0064] Preferably, after polishing, the thickness of the metal-based diamond composite material is 90-2200 μm; more preferably, the thickness of the metal-based diamond composite material is 100-2000 μm.

[0065] Specifically, the purpose of polishing is to meet subsequent packaging requirements.

[0066] A third aspect of the present invention provides an electronic device.

[0067] Specifically, the electronic device includes the sheet-like metal-based diamond composite material described in the first aspect of the present invention.

[0068] Compared with the prior art, the beneficial effects of the technical solution provided by the present invention are as follows:

[0069] (1) This invention uses diamond particles with high thermal conductivity combined with a metal-based binder. The diamond particles can form rapid heat transfer channels in the composite material, enabling the heat generated by electronic devices to be quickly conducted to the external environment. The role of the metal binder is to solidify the diamond particles, making the material denser and reducing the obstruction of heat conduction by pores. In addition, diamond particles are mostly hexahedral, octahedral, and tetrahedral, and the gaps between the closely arranged single-layer diamond particles will form a two-dimensional network structure. Therefore, a reinforcing phase with high thermal conductivity is used to fill the gaps between diamond particles and build rapid heat conduction channels in the gaps. The combined effect of the single-layer diamond particles, reinforcing phase, and binder can improve the thermal conductivity of the composite material, reduce the coefficient of thermal expansion, improve mechanical properties and reliability, and meet the heat dissipation application requirements of high thermal conductivity, high mechanical properties, large size, thin thickness, and high reliability.

[0070] (2) This invention improves the interfacial bonding between diamond particles and binder by modifying the diamond surface, forming a continuous and dense interfacial carbide layer at the interface between the binder and diamond particles, reducing the obstruction of heat conduction by the pores formed between the diamond particles and the copper matrix, which is beneficial to improving the thermal conductivity and bending strength of the metal-coated diamond composite material and reducing the coefficient of thermal expansion.

[0071] (3) The present invention coats the upper and lower surfaces of the sheet-like metal-based diamond composite material layer with a metal layer, which is beneficial for welding with electronic components during the electronic packaging process.

[0072] (4) The preparation method of the present invention is simple, low-cost, efficient and industrializable, and has broad application prospects. Attached Figure Description

[0073] Figure 1 This is a schematic diagram of the preparation process of the sheet-like metal-based diamond composite material in Embodiment 1 of the present invention. Detailed Implementation

[0074] To enable those skilled in the art to more clearly understand the technical solutions described in this invention, the following embodiments are provided for illustration. It should be noted that the following embodiments do not constitute a limitation on the scope of protection claimed by this invention.

[0075] Unless otherwise specified, the raw materials, reagents or devices used in the following examples are available from conventional commercial sources or can be obtained by existing known methods.

[0076] Examples 1-2 used the same electroplating solution. The preparation method of the electroplating solution was as follows: based on the volume of deionized water, copper methanesulfonate (70 g / L), chloride ions (hydrochloric acid 0.1 g / L), brightener (polydisulfide compound 0.3 mL / L), leveling agent (hexadecyltrimethylammonium bromide 0.5 mL / L), inhibitor (polyethylene glycol 6 mL / L), and 800 mL of deionized water were mixed to obtain the electroplating solution.

[0077] Example 1

[0078] A method for preparing a sheet-like metal-based diamond composite material includes the following steps:

[0079] (1) Preparation of diamond composite layer: Under ultrasonic assistance, uncoated diamond particles with a particle size of 900 μm were cleaned with aqua regia to remove surface impurities. After ultrasonication for 30 min, they were repeatedly cleaned with deionized water until the pH test paper showed neutrality. The cleaned diamond particles were placed in a vacuum drying oven and dried at 60℃ for 30 min to obtain dried uncoated diamond particles. The dried diamond particles were arranged in a single layer to form a two-dimensional network structure with a size of 50 mm × 50 mm, which was placed on the cathode substrate. Phosphorus copper was used as the copper plating anode, and 10 μm flake graphite was used as the reinforcing phase. The reinforcing phase was added to the electroplating solution at a rate of 10 g / L (by volume of the electroplating solution). The solution was magnetically stirred at a speed of 80 rpm. Under gravity, the reinforcing phase settled in the voids of the single-layer diamond particles. Electroplating was performed at room temperature with a current density of 20 A / dm³. 2 Under the action of current, the cathode undergoes a reduction reaction to generate elemental copper. The elemental copper binder and reinforcing agent are deposited and filled into the gaps between the single-layer diamond particles. After observing that the copper completely covers the single-layer diamond particles, the power is turned off to obtain a dense diamond composite material layer.

[0080] (2) Copper plating layer: Using the same electroplating solution as in step (1), copper is plated on the upper and lower surfaces of the diamond composite material layer obtained in step (1). Electroplating is performed at room temperature with a current density of 20 A / dm². 2 A copper layer with a thickness of 100 μm was obtained;

[0081] (3) Polishing: The copper layer obtained in step (2) was polished using a polishing machine and 2000-mesh silicon carbide sandpaper. The polishing speed was 400 rpm and the polishing pressure was 10 N. After polishing, the thickness of the diamond composite material was 1000 μm and the surface roughness was 1 μm, thus obtaining a sheet-like metal-based diamond composite material. The volume fraction of diamond was 41%, the volume fraction of the reinforcing phase was 23%, and the volume fraction of the copper binder was 36%.

[0082] Example 2

[0083] A method for preparing a sheet-like metal-based diamond composite material includes the following steps:

[0084] (1) Preparation of diamond composite layer: A single layer of tungsten-plated diamond particles with a particle size of 900 μm was tightly arranged to form a single-layer two-dimensional network structure with a size of 50 mm × 50 mm, and placed on a cathode substrate; phosphor bronze was used as the copper-plating anode, and 10 μm flake graphite was used as the reinforcing phase. The reinforcing phase was added to the electroplating solution at a rate of 10 g / L, and the solution was magnetically stirred at a speed of 80 rpm. Under the action of gravity, the reinforcing phase settled into the voids of the diamond particles. Electroplating was carried out at room temperature, and the current density during electroplating was 20 A / dm³. 2 Under the action of current, the cathode undergoes a reduction reaction to generate elemental copper. The elemental copper binder and reinforcing agent are deposited and filled into the gaps between the single-layer diamond particles. After observing that the copper completely covers the single-layer diamond particles, the power is turned off to obtain a dense diamond composite material layer.

[0085] (2) Copper plating layer: Using the same electroplating solution as in step (1), copper is plated on the upper and lower surfaces of the diamond composite material layer obtained in step (1). Electroplating is performed at room temperature with a current density of 20 A / dm². 2 A copper layer with a thickness of 100 μm was obtained;

[0086] (3) Polishing: The copper layer obtained in step (2) was polished using a polishing machine and 2000-mesh silicon carbide sandpaper. The polishing speed was 400 rpm and the polishing pressure was 10 N. The thickness of the polished diamond composite material was 1000 μm and the surface roughness was 1 μm. A sheet-like metal-based diamond composite material was obtained. The volume fraction of diamond particles was 41%, the volume fraction of reinforcing phase was 23%, and the volume fraction of copper elemental binder was 36%.

[0087] Comparative Example 1

[0088] The only difference between Comparative Example 1 and Example 1 is that Comparative Example 1 does not add a reinforcing phase, so that the volume fraction of diamond particles is 41%, the volume fraction of the reinforcing phase is 0%, and the volume fraction of copper binder is 59%, while the rest is the same as Example 1.

[0089] Performance testing

[0090] The performance of the sheet-like metal-based diamond composite materials of Examples 1-2 and Comparative Example 1 was tested, and the test results are shown in Table 1. The test methods are as follows:

[0091] Thermal conductivity: tested using the laser flare method;

[0092] Coefficient of thermal expansion: Tested using a thermal expansion meter;

[0093] Bending strength: A universal testing machine was used to perform a three-point bending test.

[0094] Table 1: Performance test results of the sheet-like metal-based diamond composite materials prepared in Examples 1-2 and Comparative Example 1

[0095] Thermal conductivity (W / (m·K)) 675 756 536 <![CDATA[Coefficient of thermal expansion (K -1 )]]> <![CDATA[6.8×10 -6 ]]> <![CDATA[5.9×10 -6 ]]> <![CDATA[7.6×10 -6 ]]> Bending strength (MPa) 274 306 215

[0096] As can be seen from Table 1, the sheet-like metal-based diamond composite material of the present invention has good thermal conductivity, flexural strength, and low coefficient of thermal expansion.

[0097] Compared to Example 1, Example 2 used surface-modified diamond particles, specifically tungsten-plated diamond particles. This resulted in the composite material of Example 2 exhibiting higher thermal conductivity and flexural strength, and a lower coefficient of thermal expansion than that of Example 1. This demonstrates that surface modification of the diamond particles improves the interfacial bonding between the diamond particles and the binder, forming a continuous and dense interfacial carbide layer at the interface. This, in turn, enhances the thermal conductivity and flexural strength of the composite material while reducing its coefficient of thermal expansion.

[0098] Compared to Example 1, Comparative Example 1 did not include a reinforcing phase. This resulted in Comparative Example 1 having lower thermal conductivity and flexural strength than Example 1, but a higher coefficient of thermal expansion, leading to inferior material properties. This demonstrates that the reinforcing phase not only creates rapid heat conduction channels in the gaps between the single-layer diamond particles, improving the thermal conductivity of the composite material, but also contributes to improving the material's mechanical properties.

[0099] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A metal-based diamond composite material, characterized in that, The material includes a diamond composite layer; the diamond composite layer includes diamond particles, a reinforcing phase, and a binder; in the diamond composite layer, the diamond particles are distributed in a single layer; the reinforcing phase and the binder fill the gaps between the single-layer diamond particles; The reinforcing phase is flake graphite; The binder is elemental copper; The diamond particles are surface-modified diamond particles, and the surface-modified diamond particles are surface-coated diamond particles. The surface-coated diamond particles are selected from at least one of surface-coated single-layer diamond particles and surface-coated composite-layer diamond particles. The coating of the single-layer diamond particles on the surface is composed of carbide-forming elements; the carbide-forming elements are selected from at least one of Cr, Ti, W, B, Zr, and Mo. The coating of the diamond particles with the surface-coated composite layer consists of a carbide-forming element and a matrix element; the carbide-forming element is selected from at least one of Cr, Ti, W, B, Zr, and Mo; the matrix element is copper. The preparation method of the metal-based diamond composite material includes the following steps: The diamond particles are distributed in a single layer and placed on a cathode substrate; the reinforcing phase and electroplating solution are mixed, and a copper-based material is used as the anode to obtain the metal-based diamond composite material by electroplating. The electroplating solution is a binder precursor solution.

2. The metal-based diamond composite material according to claim 1, characterized in that, The diamond particles have a particle size of 45-1200 μm.

3. The metal-based diamond composite material according to claim 1, characterized in that, The particle size of the reinforcing phase is 0.9 nm to 750 μm.

4. The metal-based diamond composite material according to claim 1, characterized in that, The diamond particles account for 27-65% of the volume fraction of the metal-based diamond composite material; the reinforcing phase accounts for 9-45% of the volume fraction of the metal-based diamond composite material; and the binder accounts for 18-45% of the volume fraction of the metal-based diamond composite material.

5. The metal-based diamond composite material according to claim 1, characterized in that, The metal-based diamond composite material also includes a metal coating, which is located on the upper and lower surfaces of the diamond composite material layer.

6. The metal-based diamond composite material according to claim 1, characterized in that, The electroplating process using the aforementioned electroplating method also includes surface plating and polishing.

7. An electronic device, characterized in that, Including the metal-based diamond composite material as described in any one of claims 1-6.

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