A high thermal conductivity composite material, its preparation method and application

Abstract

This invention provides a high thermal conductivity composite material, its preparation method, and its application. The high thermal conductivity composite material includes a mesh metal layer and an in-situ grown indium whisker layer on the surface of the mesh metal layer. This invention grows indium whiskers in-situ on the surface of the mesh metal layer. The mesh metal layer has high thermal conductivity, indium has a low melting point and good ductility, and indium whiskers are easier to adhere to heat-generating elements compared to indium grains. The in-situ grown indium whiskers on the surface of the mesh metal layer increases the contact area between the thermally conductive material and the heat-generating element, enabling the heat-generating element to effectively dissipate heat and effectively solving the heat generation problem caused by insufficient heat dissipation efficiency of the heat-generating element.

Description

Technical Field

[0001] This invention belongs to the field of electronic packaging materials, and relates to a high thermal conductivity composite material, its preparation method and application. Background Technology

[0002] With societal progress and development, the high integration of electronic components has become a trend. However, in actual operation, high heat flux density can lead to device overheating and failure. Therefore, solving the heat dissipation problem is urgent to extend device lifespan. In general, heat dissipation has always been one of the major obstacles to the high integration of electronic components.

[0003] Commercially available thermal interface materials are often used to fill the gap between heat-generating elements and heat sinks. Traditional thermal interface materials are mostly polymer-based, such as thermal pastes and adhesives. For example, patent CN107446525A discloses a paste-like thermal adhesive containing a conductive polymer. This patent uses a conductive polymer as a thermally conductive filler to create a thermally conductive adhesive. The adhesive components include a polymer, a conductive polymer thermally conductive filler, nano-ceramic thermally conductive filler, nano-metal thermally conductive filler, and functional carbon materials. Patent CN1916105 also discloses a thermal paste comprising a polymer matrix with different thermal conductivity coefficients and a thermally conductive filler. The thermally conductive filler and polymer matrix are mixed in a mass ratio of 3:1 to 7:1 to form the thermal paste. However, polymers themselves have low thermal conductivity, and adding highly thermally conductive microparticles as fillers cannot significantly improve thermal conductivity, thus failing to improve heat dissipation efficiency. Since metals have a thermal conductivity an order of magnitude higher than that of polymers, researchers are now turning their attention to high thermal conductivity metals as thermal interface materials to improve heat dissipation efficiency.

[0004] However, the current contact effect between metal thermal conductive materials and heat-generating components is poor, which affects the heat dissipation effect to a certain extent. Therefore, how to overcome the shortcomings of insufficient thermal conductivity of traditional thermal interface materials and prepare composite thermal conductive materials with better morphology to achieve the effect and function of optimizing heat dissipation efficiency is an urgent problem to be solved in thermal conductive materials. Summary of the Invention

[0005] To address the problems existing in the prior art, the present invention aims to provide a high thermal conductivity composite material, its preparation method, and its application. The present invention involves in-situ growth of indium whiskers on the surface of a mesh metal layer. The mesh metal layer has high thermal conductivity, while indium has a low melting point and good ductility. Furthermore, indium whiskers are easier to adhere to heat-generating elements compared to indium grains. The in-situ growth of indium whiskers on the surface of the mesh metal layer increases the contact area between the thermally conductive material and the heat-generating element, enabling the heat-generating element to effectively dissipate heat and effectively solving the overheating problem caused by insufficient heat dissipation efficiency of the heat-generating element.

[0006] In this invention, the thermal conductivity of the high thermal conductivity composite material is not less than 80 W / m·K.

[0007] To achieve this objective, the present invention employs the following technical solution:

[0008] In a first aspect, the present invention provides a high thermal conductivity composite material, the high thermal conductivity composite material comprising a mesh metal layer and an indium whisker layer grown in situ on the surface of the mesh metal layer.

[0009] The high thermal conductivity composite material of the present invention includes a mesh metal layer and an indium whisker layer grown in situ on the surface of the mesh metal layer. The mesh metal layer has high thermal conductivity, and indium has a low melting point and good ductility. The metal mesh structure of the mesh metal layer allows indium whiskers to be grown on the surface of the mesh metal layer by electroplating under a certain current density. Compared with indium grains, indium whiskers are easier to adhere to the heat-generating element. The indium whiskers grown on the surface of the mesh metal layer can increase the contact area between the thermally conductive material and the heat-generating element, enabling the heat-generating element to dissipate heat effectively. Furthermore, the in-situ growth method makes the indium whiskers bond more tightly to the mesh metal layer, reducing heat transfer resistance and effectively solving the heat generation problem caused by insufficient heat dissipation efficiency of the heat-generating element.

[0010] Preferably, the mesh metal layer comprises a copper mesh, which has high thermal conductivity.

[0011] Preferably, the mesh size of the copper mesh is 300 to 500 mesh, for example, it can be 300 mesh, 320 mesh, 340 mesh, 360 mesh, 380 mesh, 400 mesh, 420 mesh, 440 mesh, 460 mesh, 480 mesh or 500 mesh, etc. The mesh size of the copper mesh within a suitable range can enable better growth of whiskers. When the copper mesh aperture is too large, the actual area of ​​the cathode is small, and the area of ​​the substrate on which the seed crystal can attach is small, which is insufficient to support the growth of whiskers. When the copper mesh aperture is too small, the edges and tips are dense, and the grains tend to merge into sheets after nucleation and growth, making it difficult to form whiskers.

[0012] Preferably, the thickness of the mesh metal layer is 30 to 100 μm, for example, it can be 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm or 100 μm.

[0013] Preferably, the thickness of the high thermal conductivity composite material is 150-250 μm, for example, it can be 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, 200 μm, 210 μm, 220 μm, 230 μm, 240 μm or 250 μm.

[0014] In this invention, by further optimizing the thickness of the mesh metal layer and the thickness of the high thermal conductivity composite material, the overall thermal conductivity can be optimized. When the thickness of the mesh metal layer is >100μm, the overall hardness of the thermally conductive composite material increases, resulting in insufficient material flexibility. When the thickness of the high thermal conductivity composite material is >250μm, due to the low thermal conductivity of indium, when indium accounts for a large proportion in the composite material, the overall thermal conductivity will be reduced.

[0015] Preferably, the purity of the metal in the mesh metal layer and the indium in the indium whisker layer is not less than 99.99%, for example, it can be 99.99%, 99.999%, or 99.9999%.

[0016] In a second aspect, the present invention provides a method for preparing a high thermal conductivity composite material according to the first aspect, the method comprising:

[0017] The mesh metal layer was used as the cathode for electroplating in an indium-containing plating bath at a current density of 2.5–3.5 A / dm³. 2 The electroplating time is 2.5 to 3 hours to obtain a high thermal conductivity composite material.

[0018] In this invention, the electroplating current density is 2.5–3.5 A / dm². 2 For example, it could be 2.5A / dm 2 2.6A / dm 2 2.7A / dm 2 2.8A / dm 2 2.9A / dm 2 3A / dm 2 3.1A / dm 2 3.2A / dm 2 3.3A / dm 2 3.4A / dm 2 Or 3.5A / dm 2 wait.

[0019] In this invention, the electroplating time is 2.5 to 3 hours, for example, 2.5 hours, 2.6 hours, 2.7 hours, 2.8 hours, 2.9 hours or 3 hours, and more preferably 3 hours. When the electroplating time is too short, the whisker growth is not obvious. When the electroplating time is too long, the thickness of the indium whisker layer in the high thermal conductivity composite material will be too high, and the thermal conductivity will decrease.

[0020] In this invention, the electroplating temperature is room temperature, and the high thermal conductivity composite material obtained after electroplating is cleaned with alcohol and sealed for storage.

[0021] Existing technologies have not yet achieved in-situ growth of indium whiskers on a metal layer. This invention uses a mesh metal layer as the cathode and indium as the anode, employing electroplating. Combining the high thermal conductivity of the mesh metal layer with the low melting point and good ductility of indium, the microstructure of the coating is altered by changing the current density and electroplating time—indium whiskers grow on the cathode, thus depositing an indium whisker layer on the mesh metal layer substrate. Compared to indium grains, indium whiskers are easier to adhere to the heat-generating element, increasing the contact area between the thermally conductive material and the heat-generating element, enabling the heat-generating element to effectively dissipate heat, and effectively solving the heat generation problem caused by insufficient heat dissipation efficiency of the heat-generating element.

[0022] The in-situ growth principle of indium whiskers in this invention is as follows: The mesh metal layer has many edges and corners, and the actual current density at the edges and corners is much greater than the average current density. At the same time, according to the Tafel formula, the overpotential is large at the high current density. Indium first nucleates at the edges and corners. The cation concentration at the nucleation site is low. Since ion diffusion takes time and there is no substrate attached to the crystal nuclei at the mesh of the mesh metal layer, the nucleated crystal nuclei grow rapidly in the direction of high cation concentration, forming an indium whisker coating.

[0023] Preferably, during the electroplating process, the distance between the anode and cathode is 3 to 12 cm, for example, it can be 3 cm, 4 cm, 5 cm, 6 cm, 7 cm, 8 cm, 9 cm, 10 cm, 10.5 cm, 11 cm, 11.5 cm or 12 cm, etc.

[0024] Preferably, the indium-containing electroplating solution includes indium aminosulfonate, sodium aminosulfonate, aminosulfonic acid, and sodium chloride.

[0025] Preferably, the pH of the indium-containing electroplating solution is 1.8 to 2.0, for example, it can be 1.8, 1.85, 1.9, 1.95 or 2.0.

[0026] As a preferred embodiment of the preparation method described in this invention, the concentration of indium sulfamate in the indium-containing electroplating solution is 100-110 g / L, for example, it can be 100 g / L, 102 g / L, 105 g / L, 108 g / L or 110 g / L, etc.

[0027] Preferably, the concentration of sodium aminosulfonate in the indium-containing electroplating solution is 140-160 g / L, for example, it can be 140 g / L, 142 g / L, 146 g / L, 148 g / L, 150 g / L, 152 g / L, 155 g / L, 158 g / L or 160 g / L, etc.

[0028] Preferably, the concentration of aminosulfonic acid in the indium-containing electroplating solution is 20-30 g / L, for example, it can be 20 g / L, 22 g / L, 25 g / L, 28 g / L or 30 g / L.

[0029] Preferably, the concentration of sodium chloride in the indium-containing electroplating solution is 40-50 g / L, for example, it can be 40 g / L, 42 g / L, 45 g / L, 48 g / L or 50 g / L.

[0030] As a preferred technical solution of the preparation method described in this invention, the mesh metal layer can be pretreated to obtain a fresh surface before electroplating.

[0031] As a preferred embodiment of the preparation method of the present invention, the preparation method includes:

[0032] (1) A copper mesh with a thickness of 30-100 μm is used as the cathode and ultrasonically washed in a mixed solvent of ethanol and acetone. After washing, it is soaked in hydrochloric acid to obtain a pretreated copper mesh.

[0033] (2) The pretreated copper mesh from step (1) is electroplated in an indium-containing electroplating solution, wherein the electroplating current density is 2.5–3.5 A / dm². 2 The time was 2.5 to 3 hours, the distance between the anode and cathode was 10 to 12 cm, and a high thermal conductivity composite material with a thickness of 150 to 250 μm was obtained.

[0034] The indium-containing electroplating solution contains indium sulfamate, sodium sulfamate, sulfamic acid, and sodium chloride. The concentration of indium sulfamate is 100–110 g / L, the concentration of sodium sulfamate is 140–160 g / L, the concentration of sulfamic acid is 20–30 g / L, and the concentration of sodium chloride is 40–50 g / L. The pH of the indium-containing electroplating solution is 1.8–2.0.

[0035] Thirdly, the present invention provides an application of the high thermal conductivity composite material as described in the first aspect in the field of electronic packaging.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] The high thermal conductivity composite material of the present invention includes a mesh metal layer and an indium whisker layer grown in situ on the surface of the mesh metal layer. The mesh metal layer has high thermal conductivity, and indium has a low melting point and good ductility. The metal mesh structure of the mesh metal layer allows indium whiskers to be grown on the surface of the mesh metal layer by electroplating under a certain current density. Compared with indium grains, indium whiskers are easier to adhere to the heat-generating element. The indium whiskers grown on the surface of the mesh metal layer can increase the contact area between the thermally conductive material and the heat-generating element, enabling the heat-generating element to dissipate heat effectively. Furthermore, the in-situ growth method makes the indium whiskers bond more tightly to the mesh metal layer, reducing heat transfer resistance and effectively solving the heat generation problem caused by insufficient heat dissipation efficiency of the heat-generating element. Attached Figure Description

[0038] Figure 1 This is a SEM image of the high thermal conductivity composite material prepared in Example 1 of the present invention.

[0039] Figure 2 This is a SEM image of the high thermal conductivity composite material prepared in Example 1 of the present invention.

[0040] Figure 3 This is a SEM image of the high thermal conductivity composite material prepared in Example 2 of the present invention.

[0041] Figure 4 This is a SEM image of the high thermal conductivity composite material prepared in Example 3 of the present invention.

[0042] Figure 5 This is a SEM image of the high thermal conductivity composite material prepared in Comparative Example 1 of this invention.

[0043] Figure 6 This is a SEM image of the high thermal conductivity composite material prepared in Comparative Example 2 of this invention.

[0044] Figure 7 This is a physical image of the cathode during the electroplating process in Comparative Example 3 of this invention.

[0045] Figure 8 This is a SEM image of the high thermal conductivity composite material prepared in Comparative Example 5 of this invention. Detailed Implementation

[0046] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0047] Example 1

[0048] This embodiment provides a high thermal conductivity composite material, which includes a copper mesh and an in-situ grown indium whisker layer on the surface of the copper mesh. The thickness of the high thermal conductivity composite material is 200 μm, the thickness of the copper mesh is 75 μm, and the mesh size is 400 mesh.

[0049] This embodiment also provides a method for preparing the above-mentioned high thermal conductivity composite material, including:

[0050] (1) Preparation of indium-containing electroplating solution: The composition of indium-containing electroplating solution is 105.36 g / L indium aminosulfonate, 150 g / L sodium aminosulfonate, 26.48 g / L aminosulfonic acid, and 45.54 g / L sodium chloride. The pH of indium-containing electroplating solution is 1.8.

[0051] (2) Preparation of cathode: A 75μm thick, 500-mesh copper mesh was used as the cathode and cut into sheet-like copper mesh with a size of 25mm×25mm to prepare the cathode;

[0052] (3) Pretreatment: The cathode prepared in step (2) is ultrasonically washed in anhydrous ethanol and anhydrous acetone for 15 min, repeated three times to remove organic contaminants adhering to the copper surface; then it is immersed and washed in 200 mL of 100 g / L 37% HCl for 10 min to remove surface oxide scale and other substances, thus completing the pretreatment of the cathode.

[0053] (4) Electroplating: The distance between the anode and cathode for electroplating is 12cm. Prepare electroplating equipment such as a DC power supply and electroplating tank, as well as electroplating raw materials such as the anode, the cathode after pretreatment in step (3), and the indium-containing electroplating solution prepared in step (1). Electroplating is carried out at room temperature with a current density of 3A / dm³. 2 The process was carried out over 3 hours, resulting in a high thermal conductivity composite material with a thickness of 200 μm.

[0054] The morphology and structure of the high thermal conductivity composite material prepared in this embodiment were observed using a scanning electron microscope. The SEM image of the high thermal conductivity composite material prepared in this embodiment is shown below. Figure 1 and Figure 2 As shown, from Figure 1 and Figure 2 As can be seen, the preparation method of this embodiment produces whisker morphology, and the thermal conductivity of the high thermal conductivity composite material is 82.14 W / mK, and the hardness is 7.7 HV.

[0055] Example 2

[0056] This embodiment provides a high thermal conductivity composite material, which includes a copper mesh and an in-situ grown indium whisker layer on the surface of the copper mesh. The thickness of the high thermal conductivity composite material is 150 μm, the thickness of the copper mesh is 100 μm, and the mesh size is 300 mesh.

[0057] This embodiment also provides a method for preparing the above-mentioned high thermal conductivity composite material, including:

[0058] (1) Preparation of indium-containing electroplating solution: The composition of indium-containing electroplating solution is 105.36 g / L indium aminosulfonate, 150 g / L sodium aminosulfonate, 26.48 g / L aminosulfonic acid, and 45.54 g / L sodium chloride. The pH of indium-containing electroplating solution is 1.9.

[0059] (2) Preparation of cathode: A 100μm thick, 300-mesh copper mesh was used as the cathode and cut into sheet-like copper mesh with a size of 25mm×25mm to prepare the cathode;

[0060] (3) Pretreatment: The cathode prepared in step (2) is ultrasonically washed in anhydrous ethanol and anhydrous acetone for 15 min, repeated three times to remove organic contaminants adhering to the copper surface; then it is immersed and washed in 200 mL of 100 g / L 37% HCl for 10 min to remove surface oxide scale and other substances, thus completing the pretreatment of the cathode.

[0061] (4) Electroplating: The distance between the anode and cathode in the electroplating process is 12cm. Prepare a DC power supply, electroplating tank, and other electroplating equipment, as well as the anode, the cathode after pretreatment in step (3), and the indium-containing electroplating solution prepared in step (1). Electroplating is carried out at room temperature with a current density of 2.5A / dm². 2 The process took 3 hours, resulting in a high thermal conductivity composite material with a thickness of 150 μm.

[0062] The SEM image of the high thermal conductivity composite material prepared in this embodiment is shown below. Figure 3 As shown, from Figure 3 It can be seen that the preparation method of this embodiment can grow whisker morphology, and the thermal conductivity of the high thermal conductivity composite material is 92.9 W / mK and the hardness is 8.9 HV.

[0063] Example 3

[0064] This embodiment provides a high thermal conductivity composite material, which includes a copper mesh and an in-situ grown indium whisker layer on the surface of the copper mesh. The thickness of the high thermal conductivity composite material is 250 μm, the thickness of the copper mesh is 30 μm, and the mesh size is 500 mesh.

[0065] This embodiment also provides a method for preparing the above-mentioned high thermal conductivity composite material, including:

[0066] (1) Preparation of indium-containing electroplating solution: The composition of indium-containing electroplating solution is 105.36 g / L indium aminosulfonate, 150 g / L sodium aminosulfonate, 26.48 g / L aminosulfonic acid, and 45.54 g / L sodium chloride. The pH of indium-containing electroplating solution is 2.0.

[0067] (2) Preparation of cathode: A 30μm thick, 500-mesh copper mesh was used as the cathode and cut into sheet-like copper mesh with a size of 25mm×25mm to prepare the cathode;

[0068] (3) Pretreatment: The cathode prepared in step (2) is ultrasonically washed in anhydrous ethanol and anhydrous acetone for 15 min, repeated three times to remove organic contaminants adhering to the copper surface; then it is immersed and washed in 200 mL of 100 g / L 37% HCl for 10 min to remove surface oxide scale and other substances, thus completing the pretreatment of the cathode.

[0069] (4) Electroplating: The distance between the anode and cathode in the electroplating process is 10 cm. Prepare a DC power supply, electroplating tank, and other electroplating equipment, as well as the anode, the cathode after pretreatment in step (3), and the indium-containing electroplating solution prepared in step (1). Electroplating is carried out at room temperature with a current density of 3.5 A / dm². 2 The process was carried out over 3 hours, resulting in a high thermal conductivity composite material with a thickness of 250 μm.

[0070] The SEM image of the high thermal conductivity composite material prepared in this embodiment is shown below. Figure 4 As shown, from Figure 4 It can be seen that the preparation method of this embodiment can grow whisker morphology, and the thermal conductivity of the high thermal conductivity composite material is 83.89 W / mK and the hardness is 6.2 HV.

[0071] Example 4

[0072] This embodiment provides a high thermal conductivity composite material, including a copper mesh and an in-situ grown indium whisker layer on the surface of the copper mesh. The thickness of the high thermal conductivity composite material is 215 μm, the thickness of the copper mesh is 75 μm, and the mesh size is 500 mesh.

[0073] This embodiment also provides a method for preparing the above-mentioned high thermal conductivity composite material, including:

[0074] (1) Preparation of indium-containing electroplating solution: The composition of indium-containing electroplating solution is 105.36 g / L indium aminosulfonate, 150 g / L sodium aminosulfonate, 26.48 g / L aminosulfonic acid, and 45.54 g / L sodium chloride. The pH of indium-containing electroplating solution is 1.8.

[0075] (2) Preparation of cathode: A 75μm thick, 500-mesh copper mesh was used as the cathode and cut into sheet-like copper mesh with a size of 25mm×25mm to prepare the cathode;

[0076] (3) Pretreatment: The cathode prepared in step (2) is ultrasonically washed in anhydrous ethanol and anhydrous acetone for 15 min, repeated three times to remove organic contaminants adhering to the copper surface; then it is immersed and washed in 200 mL of 100 g / L 37% HCl for 10 min to remove surface oxide scale and other substances, thus completing the pretreatment of the cathode.

[0077] (4) Electroplating: The distance between the anode and cathode in the electroplating process is 3 cm. Prepare a DC power supply, electroplating tank, and other electroplating equipment, as well as the anode, the cathode after pretreatment in step (3), and the indium-containing electroplating solution prepared in step (1). Electroplating is carried out at room temperature with a current density of 2.5 A / dm². 2 The process was carried out over 3 hours, resulting in a high thermal conductivity composite material with a thickness of 215 μm.

[0078] The high thermal conductivity composite material prepared in this embodiment has a thermal conductivity of 82.16 W / mK and a hardness of 7.1 HV.

[0079] Example 5

[0080] This embodiment provides a high thermal conductivity composite material, including a copper mesh and an in-situ grown indium whisker layer on the surface of the copper mesh. The thickness of the high thermal conductivity composite material is 245 μm, the thickness of the copper mesh is 75 μm, and the mesh size is 500 mesh.

[0081] This embodiment also provides a method for preparing the above-mentioned high thermal conductivity composite material, including:

[0082] (1) Preparation of indium-containing electroplating solution: The composition of indium-containing electroplating solution is 105.36 g / L indium aminosulfonate, 150 g / L sodium aminosulfonate, 26.48 g / L aminosulfonic acid, and 45.54 g / L sodium chloride. The pH of indium-containing electroplating solution is 1.8.

[0083] (2) Preparation of cathode: A 75μm thick, 500-mesh copper mesh was used as the cathode and cut into sheet-like copper mesh with a size of 25mm×25mm to prepare the cathode;

[0084] (3) Pretreatment: The cathode prepared in step (2) is ultrasonically washed in anhydrous ethanol and anhydrous acetone for 15 min, repeated three times to remove organic contaminants adhering to the copper surface; then it is immersed and washed in 200 mL of 100 g / L 37% HCl for 10 min to remove surface oxide scale and other substances, thus completing the pretreatment of the cathode.

[0085] (4) Electroplating: The distance between the anode and cathode in the electroplating process is 10 cm. Prepare electroplating equipment such as a DC power supply and electroplating tank, as well as electroplating raw materials such as the anode, the cathode after pretreatment in step (3), and the indium-containing electroplating solution prepared in step (1). Electroplating is carried out at room temperature with a current density of 3 A / dm³. 2 The process was carried out over 3 hours, resulting in a high thermal conductivity composite material with a thickness of 245 μm.

[0086] The high thermal conductivity composite material prepared in this embodiment has a thermal conductivity of 81.24 W / mK and a hardness of 8.8 HV.

[0087] Comparative Example 1

[0088] This comparative example provides a high thermal conductivity composite material, which is the same as Example 1 except that the copper mesh is replaced with copper foil.

[0089] The SEM image of the high thermal conductivity composite material prepared in this comparative example is shown below. Figure 5 As shown, from Figure 5As can be seen from the figure, after electroplating, indium forms a coating on the surface of copper foil. This coating has an amorphous whisker structure, resulting in a small contact area with the heat-generating element and poor heat dissipation. The hardness of the high thermal conductivity composite material in this comparative example is 14.9 HV.

[0090] Comparative Example 2

[0091] Except that the current density in step (4) is replaced with 2A / dm 2 Except for the above, everything else is the same as in Example 1.

[0092] The SEM image of the high thermal conductivity composite material prepared in this comparative example is shown below. Figure 6 As shown in the figure, the current density is 2 A / dm. 2 At that time, no whiskers are formed.

[0093] Comparative Example 3

[0094] Except that the current density in step (4) is replaced with 4A / dm 2 Except for the above, everything else is the same as in Example 1.

[0095] This comparative example demonstrates the preparation of high thermal conductivity composite materials via electroplating, such as... Figure 7 As shown, a large number of bubbles are generated on the cathode surface, making it impossible to obtain a dense plated part.

[0096] Comparative Example 4

[0097] This comparative example provides a high thermal conductivity composite material, comprising a mesh metal layer and an indium plating layer, wherein the indium plating layer does not contain whisker structures. The high thermal conductivity composite material has a thickness of 176 μm, the copper mesh has a thickness of 75 μm, and a mesh count of 500.

[0098] This comparative example also provides a method for preparing the above-mentioned high thermal conductivity composite material, including:

[0099] (1) Preparation of indium-containing electroplating solution: The composition of indium-containing electroplating solution is 105.36 g / L indium aminosulfonate, 150 g / L sodium aminosulfonate, 26.48 g / L aminosulfonic acid, and 45.54 g / L sodium chloride. The pH of indium-containing electroplating solution is 1.8.

[0100] (2) Preparation of cathode: A 75μm thick, 500-mesh copper mesh was used as the cathode and cut into sheet-like copper mesh with a size of 25mm×25mm to prepare the cathode;

[0101] (3) Pretreatment: The cathode prepared in step (2) is ultrasonically washed in anhydrous ethanol and anhydrous acetone for 15 min, repeated three times to remove organic contaminants adhering to the copper surface; then it is immersed and washed in 200 mL of 100 g / L 37% HCl for 10 min to remove surface oxide scale and other substances, thus completing the pretreatment of the cathode.

[0102] (4) Electroplating: The electrode spacing for electroplating is 10cm. Prepare electroplating equipment such as DC power supply and electroplating tank, as well as electroplating raw materials such as anode, cathode after pretreatment in step (3), and indium-containing electroplating solution prepared in step (1). Electroplating is carried out at room temperature with a current density of 2A / dm³. 2 The process was carried out over 3 hours, resulting in a high thermal conductivity composite material with a thickness of 176 μm.

[0103] The high thermal conductivity composite material prepared in this embodiment has a thermal conductivity of 73 W / mK and a hardness of 7.5 HV.

[0104] Comparative Example 5

[0105] This comparative example provides a high thermal conductivity composite material, which includes a copper mesh and an in-situ grown indium whisker layer on the surface of the copper mesh. The thickness of the high thermal conductivity composite material is 175 μm, the thickness of the copper mesh is 75 μm, and the mesh size is 400 mesh.

[0106] This comparative example also provides a method for preparing the above-mentioned high thermal conductivity composite material, including:

[0107] (1) Preparation of indium-containing electroplating solution: The composition of indium-containing electroplating solution is 105.36 g / L indium aminosulfonate, 150 g / L sodium aminosulfonate, 26.48 g / L aminosulfonic acid, and 45.54 g / L sodium chloride. The pH of indium-containing electroplating solution is 1.8.

[0108] (2) Preparation of cathode: A 75μm thick, 500-mesh copper mesh was used as the cathode and cut into sheet-like copper mesh with a size of 25mm×25mm to prepare the cathode;

[0109] (3) Pretreatment: The cathode prepared in step (2) is ultrasonically washed in anhydrous ethanol and anhydrous acetone for 15 min, repeated three times to remove organic contaminants adhering to the copper surface; then it is immersed and washed in 200 mL of 100 g / L 37% HCl for 10 min to remove surface oxide scale and other substances, thus completing the pretreatment of the cathode.

[0110] (4) Electroplating: The distance between the anode and cathode for electroplating is 12cm. Prepare electroplating equipment such as a DC power supply and electroplating tank, as well as electroplating raw materials such as the anode, the cathode after pretreatment in step (3), and the indium-containing electroplating solution prepared in step (1). Electroplating is carried out at room temperature with a current density of 3A / dm³. 2 The process was carried out over 2 hours, resulting in a high thermal conductivity composite material with a thickness of 175 μm.

[0111] The morphology and structure of the high thermal conductivity composite material prepared in this comparative example were observed using a scanning electron microscope. The SEM images of the high thermal conductivity composite material prepared in this comparative example are shown below. Figure 8 As shown, from Figure 8It can be seen that the preparation method of this embodiment produces the morphology of whiskers, but the electroplating time is relatively short, the indium whisker layer is relatively thin, and the thermal conductivity of the high thermal conductivity composite material is 68.35W / mK and the hardness is 6.9HV.

[0112] Comparative Example 6

[0113] This comparative example provides a high thermal conductivity composite material, including a copper mesh and an in-situ grown indium whisker layer on the surface of the copper mesh. The high thermal conductivity composite material has a thickness of 165 μm, the copper mesh has a thickness of 75 μm, and a mesh size of 500.

[0114] This comparative example also provides a method for preparing the above-mentioned high thermal conductivity composite material, including:

[0115] (1) Preparation of indium-containing electroplating solution: The composition of indium-containing electroplating solution is 105.36 g / L indium aminosulfonate, 150 g / L sodium aminosulfonate, 26.48 g / L aminosulfonic acid, and 45.54 g / L sodium chloride. The pH of indium-containing electroplating solution is 1.8.

[0116] (2) Preparation of cathode: A 75μm thick, 500-mesh copper mesh was used as the cathode and cut into sheet-like copper mesh with a size of 25mm×25mm to prepare the cathode;

[0117] (3) Pretreatment: The cathode prepared in step (2) is ultrasonically washed in anhydrous ethanol and anhydrous acetone for 15 min, repeated three times to remove organic contaminants adhering to the copper surface; then it is immersed and washed in 200 mL of 100 g / L 37% HCl for 10 min to remove surface oxide scale and other substances, thus completing the pretreatment of the cathode.

[0118] (4) Electroplating: The distance between the anode and cathode in the electroplating process is 10 cm. Prepare a DC power supply, electroplating tank, and other electroplating equipment, as well as the anode, the cathode after pretreatment in step (3), and the indium-containing electroplating solution prepared in step (1). Electroplating is carried out at room temperature with a current density of 2.5 A / dm². 2 The process was carried out over 2 hours, resulting in a high thermal conductivity composite material with a thickness of 165 μm.

[0119] The high thermal conductivity composite material prepared in this comparative example has a thermal conductivity of 68.3 W / mK and a hardness of 6.5 HV.

[0120] Comparative Example 7

[0121] This comparative example provides a high thermal conductivity composite material, including a copper mesh and an in-situ grown indium whisker layer on the surface of the copper mesh. The high thermal conductivity composite material has a thickness of 122 μm, the copper mesh has a thickness of 75 μm, and a mesh size of 500.

[0122] This comparative example also provides a method for preparing the above-mentioned high thermal conductivity composite material, including:

[0123] (1) Preparation of indium-containing electroplating solution: The composition of indium-containing electroplating solution is 105.36 g / L indium aminosulfonate, 150 g / L sodium aminosulfonate, 26.48 g / L aminosulfonic acid, and 45.54 g / L sodium chloride. The pH of indium-containing electroplating solution is 1.8.

[0124] (2) Preparation of cathode: A 75μm thick, 500-mesh copper mesh was used as the cathode and cut into sheet-like copper mesh with a size of 25mm×25mm to prepare the cathode;

[0125] (3) Pretreatment: The cathode prepared in step (2) is ultrasonically washed in anhydrous ethanol and anhydrous acetone for 15 min, repeated three times to remove organic contaminants adhering to the copper surface; then it is immersed and washed in 200 mL of 100 g / L 37% HCl for 10 min to remove surface oxide scale and other substances, thus completing the pretreatment of the cathode.

[0126] (4) Electroplating: The distance between the anode and cathode in the electroplating process is 10 cm. Prepare a DC power supply, electroplating tank, and other electroplating equipment, as well as the anode, the cathode after pretreatment in step (3), and the indium-containing electroplating solution prepared in step (1). Electroplating is carried out at room temperature with a current density of 2.5 A / dm². 2 The process was carried out for 1 hour, resulting in a high thermal conductivity composite material with a thickness of 122 μm.

[0127] The high thermal conductivity composite material prepared in this comparative example has a thermal conductivity of 33.2 W / mK and a hardness of 6.7 HV.

[0128] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing a high thermal conductivity composite material, characterized in that, The preparation method includes: (1) A copper mesh with a thickness of 30~100μm is used as the cathode and ultrasonically washed in a mixed solvent of ethanol and acetone. After washing, it is soaked in hydrochloric acid to obtain a pretreated copper mesh. (2) The pretreated copper mesh from step (1) is electroplated in an indium-containing electroplating solution, wherein the electroplating current density is 2.5~3.5A / dm. 2 The time was 2.5~3h, the distance between the anode and cathode was 10~12cm, and a high thermal conductivity composite material with a thickness of 150~250μm was obtained; The indium-containing electroplating solution contains indium sulfamate, sodium sulfamate, sulfamic acid, and sodium chloride. The concentration of indium sulfamate in the indium-containing electroplating solution is 100-110 g / L, the concentration of sodium sulfamate is 140-160 g / L, the concentration of sulfamic acid is 20-30 g / L, and the concentration of sodium chloride is 40-50 g / L. The pH of the indium-containing electroplating solution is 1.8-2.

0. The high thermal conductivity composite material includes a copper mesh and an in-situ grown indium whisker layer on the surface of the copper mesh.

2. The preparation method according to claim 1, characterized in that, The copper mesh has a mesh count of 300-500.

3. The preparation method according to claim 1, characterized in that, The purity of copper in the copper mesh and indium in the indium whisker layer is not less than 99.99%.

4. The application of a high thermal conductivity composite material obtained by the preparation method according to any one of claims 1-3 in the field of electronic packaging.

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