A metallic thermally conductive material, its preparation method and application

Abstract

This application discloses a metallic thermally conductive material, its preparation method, and its application, relating to the field of gallium-tin-indium alloy preparation technology. The preparation method of this metallic thermally conductive material includes the following steps: mixing molten gallium-tin-indium alloy with SiC, elemental silicon, metallic aluminum, and metallic magnesium, and smelting to obtain a molten composite metal; then, during the solidification of the molten composite metal, applying pressure of 15-30 MPa to obtain the metallic thermally conductive material. This preparation method, through the combination of components and the application of pressure during solidification, endows the resulting metallic thermally conductive material with excellent thermal conductivity, hardness, and dimensional stability. It solves the technical problems of low thermal conductivity, large coefficient of thermal expansion, and easy deformation at high temperatures, which reduces heat dissipation efficiency in metallic thermally conductive materials, thus achieving the technical effects of extending the service life of the metallic thermally conductive material and increasing its operating temperature.

Description

Technical Field

[0001] This application relates to the field of gallium-tin-indium alloy preparation technology, and in particular to a metal thermally conductive material, its preparation method and application. Background Technology

[0002] Heat dissipation components are a type of component that transfers heat from a heat source through physical or chemical means, maintaining the equipment within a safe temperature range. They are key components for ensuring the stable operation of electronic equipment, engines, and other electronic devices, playing an indispensable role in the field of electronic heat dissipation and thermal management. Ideal heat dissipation component materials need to possess excellent thermal conductivity, good dimensional stability, and a wide operating temperature range.

[0003] Aluminum-based and copper-based alloys are often used as metal materials in heat dissipation components due to their excellent thermal conductivity. However, they have drawbacks such as a large coefficient of thermal expansion, making them prone to deformation at high temperatures. This can affect the fit between the heat dissipation component and the heat source, or even damage the structure of the heat dissipation component itself, thus reducing heat dissipation efficiency. They also suffer from decreased thermal conductivity at high temperatures, resulting in a lower operating temperature. Gallium also has outstanding thermal conductivity, but elemental gallium has a low melting point, making it unsuitable for high-temperature applications. While its alloys, such as gallium-tin-indium alloys, have high melting points, their low thermal conductivity and large coefficient of thermal expansion prevent them from being ideal metal thermal conductive materials for heat dissipation components. Summary of the Invention

[0004] This application provides a metallic thermally conductive material, its preparation method, and its application, to at least solve the problems of low thermal conductivity, large coefficient of thermal expansion, easy deformation at high temperatures, and low operating temperature of metallic thermally conductive materials used in heat dissipation components in related technologies.

[0005] This application provides a method for preparing a metallic thermally conductive material, comprising the following steps:

[0006] Step S1: The molten gallium-tin-indium alloy is mixed with SiC, elemental silicon, metallic aluminum, and metallic magnesium, and then heated to obtain a molten composite metal.

[0007] Step S2: Solidify the molten composite metal to obtain a thermally conductive metal material. Apply pressure of 15~30MPa during solidification.

[0008] This application provides a metallic thermally conductive material prepared by the above-described method.

[0009] This application also provides a heat dissipation device, including the aforementioned metallic thermally conductive material.

[0010] This application discloses a metal thermal conductive material whose raw materials include gallium-tin-indium alloy, SiC, elemental silicon, aluminum, and magnesium. During the solidification stage, the material is pressurized to 15-30 MPa. The combination of these components and the pressure applied during solidification endows the metal thermal conductive material with excellent thermal conductivity, hardness, and dimensional stability. Therefore, it solves the technical problems of low thermal conductivity, high coefficient of thermal expansion, and easy deformation at high temperatures, which reduces heat dissipation efficiency. This achieves the technical effect of extending the service life of the metal thermal conductive material and increasing its operating temperature, enabling it to be better applied in high-temperature scenarios such as optoelectronic devices and avionics. Attached Figure Description

[0011] To more clearly illustrate the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 This is a SEM image of the metallic thermally conductive material obtained in Example 1 of this application;

[0013] Figure 2 These are histograms showing the thermal conductivity of the metallic thermally conductive materials prepared in Examples 1-3 and Comparative Example 1 of this application.

[0014] Figure 3 Examples 1-3 of this application and Comparative Example 1 show the hardness graphs of the metal thermally conductive materials prepared.

[0015] Figure 4 The above are bar charts showing the thermal conductivity of the metallic thermally conductive materials prepared in Examples 1, 4, and 5 of this application and Comparative Example 2.

[0016] Figure 5 The graphs show the thermal expansion coefficient of the metallic thermally conductive material prepared in Examples 1-3 of this application and Comparative Example 3, respectively, as a function of temperature.

[0017] Figure 6 This is a graph showing the change in the coefficient of thermal expansion of the metallic thermally conductive materials prepared in Examples 1, 6-8 of this application as a function of temperature.

[0018] Figure 7 Line graphs showing the hardness variation of the metallic thermally conductive materials prepared in Examples 1, 9-11, and Comparative Example 4 of this application. Detailed Implementation

[0019] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this application.

[0020] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagents or instruments.

[0021] To enable those skilled in the art to better understand the present application, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] Embodiments of this application provide a method for preparing a metallic thermally conductive material, comprising the following steps:

[0023] Step S1: The molten gallium-tin-indium alloy is mixed with SiC, elemental silicon, metallic aluminum, and metallic magnesium, and then heated to obtain a molten composite metal.

[0024] Step S2: Solidify the molten composite metal to obtain a thermally conductive metal material. Apply pressure of 15~30MPa during solidification.

[0025] Melting is a first-order phase transformation, which involves an increase in enthalpy, entropy, and volume. The temperature at which melting occurs is called the melting temperature, and the liquid phase that a solid substance transforms into after reaching the melting temperature is called the molten state.

[0026] In the preparation method of the metallic thermally conductive material provided in this application, solidification can typically be carried out at room temperature, such as 25°C, without limitation.

[0027] The metallic thermally conductive material prepared by this method has a lower coefficient of thermal expansion, higher thermal conductivity and hardness. It can be used as a thermally conductive material at higher temperatures without easily deforming and affecting heat dissipation and subsequent use. It has high reliability and durability.

[0028] The use of gallium-tin-indium alloy gives this metal thermal conductive material a certain basic thermal conductivity; the addition of SiC further improves the thermal conductivity and hardness of the metal thermal conductive material; the addition of elemental silicon, metallic aluminum, and metallic magnesium helps to reduce the coefficient of thermal expansion of this metal thermal conductive material; and a certain solidification pressure gives this metal thermal conductive material higher hardness. In this application, through the synergistic combination of the composition of the metal thermal conductive material and the preparation process, the phase composition, microstructure, interfacial bonding, and internal stress state of the material are controlled, thereby optimizing the thermal conductivity, hardness, and coefficient of thermal expansion.

[0029] Specifically, gallium-tin-indium (GaTi) alloys have a high density of free electrons. Under an applied temperature gradient, these free electrons transfer heat through directional movement, resulting in a high basic thermal conductivity. SiC is a high thermal conductivity ceramic phase with strong interatomic covalent bonds and high atomic vibration frequencies in its crystal structure, allowing it to transfer heat via phonon thermal conduction. SiC dispersed within GaTi alloys forms a "thermal conduction network," compensating for potential thermal pathway defects in the GaTi alloy, reducing interfacial thermal resistance, and thus synergistically improving overall thermal conductivity. Simultaneously, SiC itself possesses extremely high hardness and strong interfacial bonding with GaTi alloys. When SiC is embedded as a reinforcing phase in GaTi alloys, it effectively hinders dislocation movement, increases material hardness through dispersion strengthening, and can also bear external loads, reducing matrix deformation and further enhancing material rigidity. Elemental silicon has a stable crystal structure, high interatomic bond energy, small atomic vibration amplitude, and low volume change rate with increasing temperature. Elemental silicon added to GaTi alloys can dilute the high expansion characteristics of the metal matrix through physical mixing effects, thereby reducing the overall coefficient of thermal expansion. The low density of aluminum and magnesium allows for further adjustment of the phase composition and microstructure of the final thermally conductive metallic material. Aluminum can form a solid solution with gallium-tin-indium alloys, which strengthens the lattice and reduces the amplitude of thermal vibrations to some extent. Magnesium can form low-expansion compounds, such as Mg2Si, with other components in the alloy, further optimizing the overall thermal stability through the low-expansion characteristics of the second phase. Applying pressure during solidification can encourage the liquid metal to fill micropores, reducing defects such as porosity and shrinkage, increasing the material's density and enhancing its resistance to plastic deformation. It can also increase the nucleation rate, inhibit grain growth, and create a fine-grain strengthening effect. The finer grains form more grain boundaries, increasing the resistance to dislocation movement and thus increasing the material's hardness. Furthermore, the external pressure can leave some compressive stress after solidification, offsetting the tensile stress caused by the external load, effectively improving the material's yield strength and hardness.

[0030] In some optional embodiments, in step S1, SiC is added to the molten gallium-tin-indium alloy and heated at a first heating temperature to obtain an intermediate molten metal; the first heating temperature is 295~305°C.

[0031] Then, elemental silicon, aluminum, and magnesium are added to the intermediate molten metal, and the mixture is heated sequentially at a second heating temperature and a third heating temperature to obtain a molten composite metal; or, any two of elemental silicon, aluminum, and magnesium are added to the intermediate molten metal, and after heating at the second heating temperature, the mixture is cooled to a third heating temperature, and the remaining portion of elemental silicon, aluminum, and magnesium is added, and the mixture is heated at the third heating temperature to obtain a molten composite metal; wherein the second heating temperature is 745~755℃ and the third heating temperature is 695~705℃.

[0032] In some optional embodiments, the molten composite metal comprises, by mass parts: 100 parts of gallium-tin-indium alloy and SiC, 0.8 to 5.2 parts of elemental silicon, 0.8 to 1.2 parts of aluminum, and 0.8 to 1.2 parts of magnesium.

[0033] In some optional embodiments, the heating treatment time at the first heating temperature, the second heating temperature, or the third heating temperature is 8 to 24 minutes.

[0034] In some optional embodiments, the heat treatment process also includes a stirring operation; the stirring time is 8 to 12 minutes. Typically, and not limited to, the stirring is performed in the first half of the heat treatment to make the components more uniformly mixed; the stirring includes mechanical stirring; further, the stirring speed is 450 to 550 rpm / min.

[0035] In some optional embodiments, step S1, the method for preparing the molten composite metal includes:

[0036] By mass, 0.8-1.2 parts of metallic aluminum and 4.8-5.2 parts of elemental silicon are added to 100 parts of intermediate molten metal. The mixture is heated to a second heating temperature for heat treatment. During the heat treatment, the mixture is stirred for 8-12 minutes, then the stirring is stopped and the temperature is maintained for 8-12 minutes. The mixture is then cooled to a third heating temperature, and 0.8-1.2 parts of metallic magnesium are added. Heat treatment is then carried out at the third heating temperature. During the heat treatment, the mixture is stirred for 8-12 minutes, then the stirring is stopped and the temperature is maintained for 8-12 minutes to obtain a molten composite metal.

[0037] Alternatively, by mass, 0.8-1.2 parts of metallic aluminum, 4.8-5.2 parts of elemental silicon, and 0.8-1.2 parts of metallic magnesium are added to 100 parts of intermediate molten metal. The mixture is heated to a second heating temperature for heat treatment. During the heat treatment, the mixture is stirred for 8-12 minutes, then the stirring is stopped and the temperature is maintained for 8-12 minutes. The mixture is then cooled to a third heating temperature and heated for 8-12 minutes to obtain the molten composite metal.

[0038] Alternatively, by mass, 0.8-1.2 parts of metallic aluminum and 0.8-1.2 parts of metallic magnesium are added to 100 parts of intermediate molten metal. The mixture is heated to a second heating temperature for heat treatment. During the heat treatment, the mixture is stirred for 8-12 minutes, then the stirring is stopped and the temperature is maintained for 8-12 minutes. The mixture is then cooled to a third heating temperature, and 4.8-5.2 parts of elemental silicon are added. Heat treatment is then carried out at the third heating temperature, with the mixture stirred for 8-12 minutes, then the stirring is stopped and the temperature is maintained for 8-12 minutes to obtain the molten composite metal.

[0039] Alternatively, by mass, 0.8-1.2 parts of metallic aluminum and 0.8-1.2 parts of elemental silicon are added to 100 parts of intermediate molten metal. The mixture is heated to a second heating temperature for heat treatment. During the heat treatment, the mixture is stirred for 8-12 minutes, then the stirring is stopped and the temperature is maintained for 8-12 minutes. The mixture is then cooled to a third heating temperature, and 0.8-1.2 parts of metallic magnesium are added. Heat treatment is then carried out at the third heating temperature, with the mixture stirred for 8-12 minutes, then the stirring is stopped and the temperature is maintained for 8-12 minutes to obtain the molten composite metal.

[0040] In some more preferred embodiments, in step S1, the method for preparing the molten composite metal is as follows: 0.8-1.2 parts by mass of metallic aluminum and 4.8-5.2 parts by mass of elemental silicon are added to 100 parts of intermediate molten metal. The mixture is heated to a second heating temperature for heat treatment. During the heat treatment, the mixture is stirred for 8-12 minutes, then the stirring is stopped and the temperature is maintained for 8-12 minutes. The mixture is then cooled to a third heating temperature, and 0.8-1.2 parts by mass of metallic magnesium are added. Heat treatment is then performed at the third heating temperature, with the mixture stirred for 8-12 minutes and maintained for 8-12 minutes, to obtain the molten composite metal. Using the method of first adding metallic aluminum and elemental silicon to the intermediate molten metal, heating for a certain time, cooling down, adding metallic magnesium, and continuing the heating process, and using 0.8-1.2 parts by mass of metallic aluminum, 4.8-5.2 parts by mass of elemental silicon, and 0.8-1.2 parts by mass of metallic magnesium for every 100 parts by mass of intermediate molten metal, can further reduce the coefficient of thermal expansion of the final metal thermally conductive material.

[0041] In some optional embodiments, the gallium-tin-indium alloy contains, by mass percentage, 60% to 70% gallium, 20% to 30% tin, and 5% to 10% indium. For example, the gallium-tin-indium alloy contains, by mass percentage, 65% gallium, 30% tin, and 5% indium; or, 60% gallium, 30% tin, and 10% indium; or, 70% gallium, 20% tin, and 10% indium.

[0042] In some optional embodiments, the mass ratio of gallium tin indium alloy to SiC in the molten composite metal is 7:3 to 9:1. For example, the mass ratio of gallium tin indium alloy to SiC can be 7:3, 8:2, or 9:1.

[0043] In some more preferred embodiments, the mass ratio of gallium tin indium alloy to SiC in the molten composite metal is 7:3. Since SiC itself has extremely high hardness, under the condition of controlling the mass ratio of SiC to a higher level, the resulting metal thermal conductive material can also have higher hardness. At the same time, controlling the mass ratio of the two to 7:2 will not have a negative impact on other properties of the metal thermal conductive material.

[0044] In some optional embodiments, the preparation method of gallium-tin-indium alloy includes: taking gallium, tin and indium by mass percentage, heating to 295~305°C under an inert atmosphere to melt the gallium, tin and indium to a completely molten state, holding at the temperature for 8~12 minutes to ensure that the gallium, tin and indium are fully and uniformly mixed in the molten state to obtain gallium-tin-indium alloy.

[0045] Inert atmospheres include at least one of nitrogen atmospheres and rare gas atmospheres; for example, nitrogen atmospheres, argon atmospheres, or mixed atmospheres of nitrogen and argon can be selected as inert atmospheres.

[0046] In some optional embodiments, the preparation method includes the following steps:

[0047] S1: In a gallium-tin-indium alloy, by mass percentage, it contains 70% gallium, 20% tin, and 10% indium. Take metallic gallium, metallic tin, and metallic indium, heat them to 300°C under an inert atmosphere, and hold for 10 minutes to obtain a gallium-tin-indium alloy. At this gallium-tin-indium ratio, the resulting metal thermally conductive material has higher thermal conductivity.

[0048] S2: At the first heating temperature, 30 parts by mass of SiC are added to 70 parts of gallium-tin-indium alloy, stirred for 20 minutes, and kept at the temperature to obtain intermediate molten metal; at this mass ratio of gallium-tin-indium alloy to SiC, the resulting metal thermally conductive material has higher strength;

[0049] S3: By mass, add 1 part of metallic aluminum and 5 parts of elemental silicon to 100 parts of intermediate molten metal, heat to the second heating temperature for heating treatment, stir for 10 minutes during the heating treatment, then stop stirring and keep warm for 10 minutes, cool down to the third heating temperature, add 1 part of metallic magnesium, and heat at the third heating temperature, stir for 10 minutes during the heating treatment, then stop stirring and keep warm for 10 minutes to obtain molten composite metal;

[0050] S4: At room temperature, the molten composite metal is solidified to obtain a thermally conductive metal material. During solidification, a pressure of 15~30MPa is applied.

[0051] To further improve the purity of the obtained metallic thermally conductive material, before solidification, a third step is included: adding hexachloroethane to the molten composite metal at a third temperature, followed by stirring, settling, and slag removal. The mass ratio of hexachloroethane to the molten composite metal is 1:205~215, the stirring time is 5 minutes, and the settling time is 15 minutes. Hexachloroethane decomposes into gases at high temperatures. These gases form bubbles in the molten composite metal, adsorbing and carrying non-metallic impurities to the surface of the molten composite metal, which are then removed by slag removal. This process further improves the density and mechanical properties of the alloy.

[0052] To facilitate better SiC doping in metallic thermally conductive materials, a cleaning step is included before preparation. Specifically, SiC particles are first cleaned in hydrofluoric acid to remove surface oxides, followed by a second cleaned in a silane coupling agent and ethanol solution at a mass ratio of 1:98-102, and then dried. The hydrofluoric acid concentration is 5 wt%, and the first and second cleansing times are 30 minutes each. The cleaning method includes ultrasonic cleaning. The drying temperature is 60°C, and the time is 2 hours, ensuring the SiC particles are completely dry.

[0053] According to one aspect of the embodiments of this application, a metal thermally conductive material prepared by any of the above-described methods for preparing metal thermally conductive materials is also provided.

[0054] According to one aspect of the embodiments of this application, a heat dissipation device is also provided, including the aforementioned metallic thermally conductive material. It can conduct heat more efficiently, improve the cooling efficiency of the heat dissipation device, and avoid problems such as performance degradation, operational failures, and hardware damage caused by overheating of the device being cooled, thus ensuring the stable operation of the device and extending its service life. At the same time, this heat dissipation device still has good thermal conductivity at high temperatures, making it applicable to a wide range of working conditions and further helping to broaden the application scenarios of the device being cooled.

[0055] Example 1

[0056] This embodiment provides a metallic thermally conductive material and its preparation method, including the following steps:

[0057] (1) Take SiC particles and ultrasonically clean them in 5% hydrofluoric acid for 30 min to remove surface oxides; then ultrasonically clean them in a silane coupling agent KH570 and ethanol solution with a mass ratio of 1:100 for 30 min; then dry them in a drying oven at 60℃ for 2 h to obtain pretreated SiC particles.

[0058] (2) According to the gallium-tin-indium alloy, the mass percentage contains 70% gallium, 20% tin and 10% indium. Weigh out metallic gallium, metallic tin and metallic indium, mix metallic gallium, metallic tin and metallic indium under nitrogen atmosphere and heat to 300°C to completely melt them, and keep them in the molten state for 10 min to obtain gallium-tin-indium alloy.

[0059] (3) By mass, add 30 parts of SiC particles pretreated in step (1) to 70 parts of molten gallium tin indium alloy at 300°C, and heat at 300°C. During the heat treatment, first use a stirrer to stir at a speed of 500 rmp / min for 20 min to make it evenly mixed, then stop stirring and continue to heat at 300°C to obtain intermediate molten metal.

[0060] (4) At 300°C, add 1 part of aluminum and 5 parts of elemental silicon to 100 parts of intermediate molten metal by mass. Heat the mixture to 750°C and stir at 500 rpm for 10 min to mix it evenly. Then stop stirring and continue heating for 10 min. Cool down to 700°C and add 1 part of magnesium. Heat the mixture at 500 rpm for 10 min to mix it evenly. Then stop stirring and continue heating for 10 min to obtain the molten composite metal.

[0061] (5) Add 0.5 parts of C2Cl6 to 107 parts of molten composite metal by mass, stir for 5 min, let stand for 15 min, and then remove the slag.

[0062] (6) The molten composite metal after slag removal is placed into a mold for cooling and solidification. The solidification temperature is 25℃ and the pressure during solidification is 30MPa to obtain a metal thermally conductive material.

[0063] Example 2

[0064] This embodiment provides a metal thermal conductive material and its preparation method. Compared with embodiment 1, the only difference is that step (3) is: by mass, 20 parts of SiC particles pretreated in step (1) are added to 80 parts of molten gallium tin indium alloy at 300°C, and heated at 300°C. During the heating treatment, the mixture is first stirred at 500 rmp / min for 20 min to make it uniform, and then the stirring is stopped. The temperature is maintained at 300°C for the heating treatment to obtain intermediate molten metal.

[0065] Example 3

[0066] This embodiment provides a metal thermally conductive material and its preparation method. Compared with embodiment 1, the only difference is that step (3) is: by mass, 10 parts of SiC particles pretreated in step (1) are added to 90 parts of molten gallium-tin-indium alloy at 300°C, and heated at 300°C. During the heating treatment, the mixture is first stirred at 500 rmp / min for 20 min to make it uniform, and then the stirring is stopped. The temperature is maintained at 300°C for further heating treatment to obtain intermediate molten metal.

[0067] Example 4

[0068] This embodiment provides a metal thermal conductive material and its preparation method. Compared with embodiment 1, the only difference is that step (2) is: according to the mass percentage of gallium-tin-indium alloy, it contains 65% gallium, 30% tin and 5% indium. Weigh out metal gallium, metal tin and metal indium. Under a nitrogen atmosphere, mix metal gallium, metal tin and metal indium and heat to 300°C to completely melt them. Keep them in the molten state for 10 minutes to obtain gallium-tin-indium alloy.

[0069] Example 5

[0070] This embodiment provides a metal thermal conductive material and its preparation method. Compared with embodiment 1, the only difference is that step (2) is: according to the mass percentage of gallium-tin-indium alloy, it contains 60% gallium, 30% tin and 10% indium. Weigh out metal gallium, metal tin and metal indium. Under a nitrogen atmosphere, mix metal gallium, metal tin and metal indium and heat to 300°C to completely melt them. Keep them in the molten state for 10 minutes to obtain gallium-tin-indium alloy.

[0071] Example 6

[0072] This embodiment provides a metal thermal conductive material and its preparation method. Compared with embodiment 1, the only difference is that step (4) is: at 300°C, by mass fraction, 1 part of aluminum, 5 parts of elemental silicon, and 1 part of magnesium are added to 100 parts of intermediate molten metal. The temperature is raised to 750°C for heat treatment. During the heat treatment, the mixture is stirred at 500 rmp / min for 10 min to make it uniform. Then the stirring is stopped, and the heat treatment is continued for 10 min. The temperature is lowered to 700°C, and the heat treatment is continued for 10 min to obtain molten composite metal.

[0073] Example 7

[0074] This embodiment provides a metal thermal conductive material and its preparation method. Compared with embodiment 1, the only difference is that step (4) is: at 300°C, add 1 part of aluminum and 1 part of magnesium to 100 parts of intermediate molten metal by mass, heat to 750°C for heat treatment. During the heat treatment, stir at 500 rpm for 10 minutes to make it evenly mixed, then stop stirring and continue heat treatment for 10 minutes. Cool down to 700°C, add 5 parts of elemental silicon, and heat treatment. During the heat treatment, stir at 500 rpm for 10 minutes to make it evenly mixed, then stop stirring and continue heat treatment for 10 minutes to obtain molten composite metal.

[0075] Example 8

[0076] This embodiment provides a metal thermal conductive material and its preparation method. Compared with embodiment 1, the only difference is that step (4) is: at 300°C, add 1 part of aluminum and 1 part of elemental silicon to 100 parts of intermediate molten metal by mass, heat to 750°C for heating treatment. During the heating treatment, stir at 500 rpm for 10 minutes to make it evenly mixed, then stop stirring and continue heating treatment for 10 minutes. Cool down to 700°C, add 1 part of magnesium, and heat treatment. During the heating treatment, stir at 500 rpm for 10 minutes to make it evenly mixed, then stop stirring and continue heating treatment for 10 minutes to obtain molten composite metal.

[0077] Example 9

[0078] This embodiment provides a metal thermal conductive material and its preparation method. Compared with embodiment 1, the only difference is that step (6) involves placing the molten composite metal after slag removal into a mold for cooling and solidification. The solidification temperature is 25°C, and the pressure during solidification is 15MPa to obtain the metal thermal conductive material.

[0079] Example 10

[0080] This embodiment provides a metal thermal conductive material and its preparation method. Compared with embodiment 1, the only difference is that step (6) involves placing the molten composite metal after slag removal into a mold for cooling and solidification. The solidification temperature is 25°C, and the pressure during solidification is 20 MPa to obtain the metal thermal conductive material.

[0081] Example 11

[0082] This embodiment provides a metal thermal conductive material and its preparation method. Compared with embodiment 1, the only difference is that step (6) involves placing the molten composite metal after slag removal into a mold for cooling and solidification. The solidification temperature is 25°C, and the pressure during solidification is 25 MPa to obtain the metal thermal conductive material.

[0083] Comparative Example 1

[0084] This comparative example provides a metal thermally conductive material and its preparation method. Compared with Example 1, the only difference is that step (1) is not performed. Step (3) is as follows: 100 parts of molten gallium-tin-indium alloy at 300°C are taken by mass and heated at 300°C. During the heating treatment, the mixture is first stirred at a speed of 500 rmp / min for 20 min to further mix it evenly. Then the stirring is stopped and the temperature is maintained at 300°C for heating treatment to obtain intermediate molten metal.

[0085] Comparative Example 2

[0086] This comparative example provides a metal thermal conductive material and its preparation method. Compared with Example 1, the only difference is that step (2) is to prepare a gallium-indium alloy. Specifically, the gallium and indium are weighed according to the mass percentage of 70% gallium and 30% indium in the gallium-indium alloy. Under a nitrogen atmosphere, the gallium and indium are mixed and heated to 300°C to completely melt them and keep them in the molten state for 10 minutes to obtain the gallium-indium alloy.

[0087] Comparative Example 3

[0088] This comparative example provides a metal thermally conductive material and its preparation method. Compared with Example 1, the only difference is that step (4) is not performed, and the intermediate molten metal obtained in step (3) is directly taken to perform step (5) and subsequent operations.

[0089] Comparative Example 4

[0090] This comparative example provides a metal thermal conductive material and its preparation method. Compared with Example 1, the only difference is that step (6) involves placing the molten composite metal after slag removal into a mold for cooling and solidification. The solidification temperature is 25°C, and the pressure during solidification is 5MPa to obtain the metal thermal conductive material.

[0091] Test Example 1

[0092] The metallic thermally conductive material obtained in Example 1 was observed under SEM. The image obtained at 10,000x magnification is shown below. Figure 1 .from Figure 1 As can be seen, a small number of sparse micropores exist on the metal surface. These are tiny micropores formed by SiC dispersed in the molten metal thermal conductive material, which can only be observed at a magnification of 10,000x. Therefore, it can be concluded that the metal thermal conductive material provided in this application has a smooth and flat surface, which can avoid the accumulation of charge at sharp parts when applied to electronic components, thereby avoiding the phenomenon of tip discharge. Furthermore, the smooth and flat metal surface can further improve the fitting accuracy during preparation, thus comprehensively extending the service life of the manufactured electronic components.

[0093] Test Example 2

[0094] The thermal conductivity and hardness of the metallic thermally conductive materials prepared in Examples 1-3 and Comparative Example 1 were tested respectively. Thermal conductivity was tested using a flat-plate thermal conductivity meter at room temperature; hardness was tested using a Rockwell hardness tester. Data processing yielded the thermal conductivity histograms of the metallic thermally conductive materials prepared in Examples 1-3 and Comparative Example 1. Figure 2 Hardness line graph (see) Figure 3 .

[0095] from Figure 2 As can be seen, the thermal conductivity of the metal thermally conductive material obtained in Comparative Example 1 without SiC is the lowest, at approximately 70 W / m·K. The thermal conductivity of the metal thermally conductive materials in Examples 1-3 with added SiC is significantly improved compared to Comparative Example 1. In Example 1, the mass ratio of molten gallium-tin-indium alloy to SiC particles is 7:3, resulting in a thermal conductivity close to 200 W / m·K; in Example 2, the mass ratio of molten gallium-tin-indium alloy to SiC particles is 8:2, resulting in a thermal conductivity of approximately 170 W / m·K; and in Example 3, the mass ratio of molten gallium-tin-indium alloy to SiC particles is 9:1, resulting in a thermal conductivity of approximately 140 W / m·K. Figure 2 In the bar chart, the thermal conductivity shows a clear and gradual increasing trend with the increase of SiC content. In Example 1, where the mass ratio of molten gallium-tin-indium alloy to SiC particles is 7:3, the thermal conductivity of the resulting metal thermal conductive material is significantly higher than that of the metal thermal conductive materials prepared with other mass ratios.

[0096] from Figure 3 As can be seen, the changing trend of metal thermal conductive materials with different SiC addition amounts is similar to... Figure 2 The trends in thermal conductivity changes were generally consistent. The metal thermal conductive material obtained in Comparative Example 1, without SiC, had the lowest hardness, around 40 HRB. The metal thermal conductive materials in Examples 1-3, with SiC added, showed significantly higher hardness compared to Comparative Example 1. Even in Example 3, where the mass ratio of molten gallium-tin-indium alloy to SiC particles was 9:1, its hardness was around 65 HRB, far exceeding that of Comparative Example 1. Compared to Examples 1 and 3, where the mass ratios of molten gallium-tin-indium alloy to SiC particles were 8:2 and 7:3 respectively, the hardness of the metal thermal conductive material gradually increased with the gradual increase in SiC content. The hardness of Example 2 was around 75 HRB, and that of Example 1 was around 87 HRB. The metal thermal conductive material obtained in Example 1, with a mass ratio of molten gallium-tin-indium alloy to SiC particles of 7:3, had the highest hardness.

[0097] Test Example 3

[0098] The thermal conductivity of the metallic thermally conductive materials prepared in Examples 1, 4, and 5, and Comparative Example 2 was tested using the same method as in Example 2. Data processing yielded the thermal conductivity histograms of the metallic thermally conductive materials prepared in Examples 1, 4, and 5, and Comparative Example 2. Figure 4 .

[0099] from Figure 4 As can be seen, Comparative Example 2 has the lowest thermal conductivity, only around 100 W / m·K. This is because Comparative Example 2 uses a gallium-indium alloy without tin as the substrate, instead of a gallium-indium-tin alloy. In Examples 1, 4, and 5, the thermal conductivity of the metal thermally conductive materials prepared using gallium-indium-tin alloy as the substrate is significantly higher than that of Comparative Example 2. In Examples 1, 4, and 5, Example 4, with gallium-indium alloy containing 65%, 30%, and 5% gallium-indium, respectively, has a relatively low thermal conductivity, likely around 170 W / m·K. Example 5, with gallium-indium alloy containing 60%, 30%, and 10% gallium-indium, respectively, has a slightly higher thermal conductivity than Example 4, but only slightly. In contrast, Example 1, with gallium-indium alloy containing 70%, 20%, and 10% gallium-indium, respectively, has a significantly higher thermal conductivity than Examples 4 and 5, reaching nearly 200 W / m·K, which is the optimal gallium-indium-tin alloy ratio in this application.

[0100] Test Example 4

[0101] The thermal expansion coefficients of the metallic thermal conductive materials prepared in Examples 1-3 and Comparative Example 3 were tested using a thermomechanical analyzer. The data were processed to obtain the curves showing the change in the thermal expansion coefficients of the metallic thermal conductive materials prepared in Examples 1-3 and Comparative Example 3 as a function of temperature. Figure 5 .

[0102] from Figure 5 As can be seen, the metallic thermally conductive material prepared in Comparative Example 3, due to the absence of aluminum, magnesium, and elemental silicon, has a significantly higher coefficient of thermal expansion, reaching as high as 16.5 × 10⁻⁶ at 25°C. -6 K -1 The coefficient of thermal expansion is as high as 21 × 10⁻⁶ at 300℃. -6 K -1As mentioned above, this material has a significant risk of deformation at both high and low temperatures, making it unsuitable for use as a thermal conductive material. In Examples 1-3, the mass ratio of molten gallium-tin-indium alloy to SiC particles varied, but all employed a method of first adding aluminum and elemental silicon, heating, stirring to achieve uniform mixing and holding at that temperature for a period, then cooling, adding magnesium, stirring to achieve uniform mixing, and holding at that temperature for a period, resulting in the addition of 1 part by mass of aluminum, 1 part by mass of magnesium, and 5 parts by mass of elemental silicon. The resulting metal thermal conductive materials all showed varying degrees of decrease in thermal expansion coefficient compared to Comparative Example 3. Specifically, in Example 1, the mass ratio of molten gallium-tin-indium alloy to SiC particles was 7:3, and the resulting metal thermal conductive material achieved a thermal expansion coefficient of 15 × 10⁻⁶. -6 K -1 The temperature is relatively high, above 50℃, and the coefficient of thermal expansion is still relatively low at 300℃, around 18×10⁻⁶. -6 K -1 Approximately. In Example 2, the mass ratio of molten gallium-tin-indium alloy to SiC particles was 8:2. Although the coefficient of thermal expansion at 300°C was lower than that of the metallic thermally conductive material obtained in Example 1, the coefficient of thermal expansion still reached 15 × 10⁻⁶. -6 K -1 The temperature was also relatively low, below 50°C. In Example 3, the mass ratio of molten gallium-tin-indium alloy to SiC particles was 9:1, although the coefficient of thermal expansion reached 15 × 10⁻⁶. -6 K -1 The temperature is relatively high, basically similar to the metallic thermally conductive material obtained in Example 1, but the coefficient of thermal expansion reaches 20 × 10⁻⁶ at 300°C. -6 K -1 At approximately the same mass ratio of gallium-tin-indium alloy to SiC, the resulting metallic thermally conductive material is more suitable for use at lower temperatures.

[0103] Test Example 5

[0104] The thermally conductive metallic materials prepared in Examples 1, 6-8 were used to test their coefficients of thermal expansion using the same method as in Test Example 4. The data were processed to obtain the curves showing the change in the coefficients of thermal expansion of the thermally conductive metallic materials prepared in Examples 1, 6-8 as a function of temperature. Figure 6 .

[0105] from Figure 6 As can be seen from Example 1, 1 part by mass of Al and 5 parts by mass of Si are added first, the mixture is heated, stirred to ensure uniform mixing, and then kept at the same temperature for a period of time. After cooling, 1 part by mass of Mg is added, and the mixture is stirred to ensure uniform mixing and then kept at the same temperature for a period of time. This method of adding aluminum, magnesium, and elemental silicon results in a metal thermally conductive material with a low coefficient of thermal expansion at high temperatures, reaching 15 × 10⁻⁶. -6 K-1 The temperature is also relatively low. In Example 7, 1 part by mass of Al and 1 part by mass of Mg were added first, the temperature was raised, and after stirring to mix evenly, the mixture was kept at the same temperature for a period of time. Then the temperature was lowered, and 5 parts by mass of Si were added. After stirring to mix evenly, the mixture was kept at the same temperature for a period of time. In this method of adding metallic aluminum, metallic magnesium, and elemental silicon, although the coefficient of thermal expansion reaches 15 × 10⁻⁶, the temperature is relatively low. -6 K -1 The temperature is also relatively low, but the coefficient of thermal expansion at 300℃ is relatively high, making it more suitable for use at low temperatures. In Example 8, 1 part by mass of Al and 1 part by mass of Si were added first, the temperature was raised, and after stirring to mix evenly, the mixture was kept at the same temperature for a period of time. Then the temperature was lowered, and 1 part by mass of Mg was added. After stirring to mix evenly, the mixture was kept at the same temperature for a period of time. In Example 6, 1 part by mass of Al, 5 parts by mass of Si, and 1 part by mass of Mg were added simultaneously, the temperature was raised, and after stirring to mix evenly, the mixture was kept at the same temperature for a period of time. Then the temperature was lowered, and the mixture was kept at the same temperature for a period of time. The growth trend of the coefficient of thermal expansion of the metal thermally conductive materials prepared by these two methods of adding materials and the mass of materials used is basically similar to that in Example 1, but the initial coefficient of thermal expansion is higher. At 25℃, the coefficient of thermal expansion of Example 8 is 15.7 × 10⁻⁶. -6 K -1 Around, in Example 6 at 16.5 × 10 -6 K -1 The overall value is relatively high. In Example 1, 1 part by mass of Al and 5 parts by mass of Si were added first, and after being kept at a certain temperature for a period of time, the temperature was lowered and then 1 part by mass of Mg was added. This is the optimal feeding method and material mass ratio.

[0106] Test Example 6

[0107] The hardness of the metallic thermally conductive materials prepared in Examples 1, 9-11, and Comparative Example 4 was tested using the same method as in Test Example 2. The obtained data are shown in Table 1. After processing the data, line graphs showing the hardness variation of the metallic thermally conductive materials prepared in Examples 1, 9-11, and Comparative Example 4 were obtained. Figure 7 .

[0108] Table 1

[0109]

[0110] Combined Table 1 and Figure 7It can be seen that in Comparative Example 4, the pressure applied during solidification was too low, only 5 MPa, resulting in a final metal thermal conductive material with a hardness of only 35 HRB, making it difficult to process and use. In Example 9, the pressure applied during solidification was increased to 15 MPa, and the hardness of the resulting metal thermal conductive material reached a relatively high value of 75 HRB. In Examples 10, 11, and 1, the pressure applied during solidification was further increased, and the hardness of the resulting metal thermal conductive material increased slowly. In actual production, a reasonable solidification pressure can be selected based on cost and the hardness requirements of the target product.

[0111] The foregoing has provided a detailed description of a metallic thermally conductive material, its preparation method, and its applications. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of these embodiments are merely illustrative of the methods and core concepts of this application. It should be noted that those skilled in the art can make various improvements and modifications to this application without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims of this application.

Claims

1. A method for producing a metal heat conducting material, characterized by, The method comprises the following steps: S1 step: mixing gallium-tin-indium alloy in a molten state with SiC, elemental silicon, aluminum metal, and magnesium metal, and performing heating treatment to obtain a molten composite metal; The gallium-tin-indium alloy contains 60-70% gallium, 20-30% tin, and 5-10% indium by mass percentage; S2 step: allowing the molten composite metal to solidify at room temperature under a pressure of 15-30 MPa to obtain a metal heat-conducting material; The molten composite metal comprises 100 parts of gallium-tin-indium alloy and SiC, 0.8-5.2 parts of elemental silicon, 0.8-1.2 parts of aluminum metal, and 0.8-1.2 parts of magnesium metal by mass fraction; In the molten composite metal, the mass ratio of gallium-tin-indium alloy to SiC is 7:3-8:

2.

2. The method for preparing the metallic thermally conductive material according to claim 1, characterized in that, In the S1 step, SiC is added to the molten gallium-tin-indium alloy, and heating treatment is performed at a first heating temperature to obtain an intermediate molten metal; the first heating temperature is 295-305 ℃; Then, elemental silicon, aluminum metal, and magnesium metal are added to the intermediate molten metal, and heating treatment is sequentially performed at a second heating temperature and a third heating temperature to obtain the molten composite metal; or, any two of elemental silicon, aluminum metal, and magnesium metal are added to the intermediate molten metal, heating treatment is performed at the second heating temperature, and then the temperature is lowered to the third heating temperature; the remaining part of elemental silicon, aluminum metal, and magnesium metal is added, and heating treatment is performed at the third heating temperature to obtain the molten composite metal; wherein the second heating temperature is 745-755 ℃, and the third heating temperature is 695-705 ℃.

3. The method for preparing the metallic thermally conductive material according to claim 2, characterized in that, The heating treatment is performed at the first heating temperature, at the second heating temperature, or at the third heating temperature for 8-24 min; And / or, stirring is further included in the heating treatment process; the stirring time is 8-12 min.

4. The method of claim 3, wherein the metal heat conducting material is prepared by a process comprising the steps of: In the S1 step, the method for preparing the molten composite metal comprises: 0.8-1.2 parts of aluminum metal, 4.8-5.2 parts of elemental silicon, and 0.8-1.2 parts of magnesium metal are added to 100 parts of the intermediate molten metal, the temperature is raised to the second heating temperature for heating treatment, stirring is first performed for 8-12 min during the heating treatment, then the stirring is stopped and heat preservation is performed for 8-12 min, the temperature is lowered to the third heating temperature, 0.8-1.2 parts of magnesium metal is added, and heating treatment is performed at the third heating temperature; during the heating treatment, stirring is first performed for 8-12 min, then the stirring is stopped and heat preservation is performed for 8-12 min to obtain the molten composite metal; Or, 0.8-1.2 parts of aluminum metal, 4.8-5.2 parts of elemental silicon, and 0.8-1.2 parts of magnesium metal are added to 100 parts of the intermediate molten metal, the temperature is raised to the second heating temperature for heating treatment, stirring is first performed for 8-12 min during the heating treatment, then the stirring is stopped and heat preservation is performed for 8-12 min, the temperature is lowered to the third heating temperature, and heating treatment is performed for 8-12 min to obtain the molten composite metal; Or, 0.8-1.2 parts of metallic aluminum and 0.8-1.2 parts of metallic magnesium are added into 100 parts of the intermediate molten metal, the temperature is raised to the second heating temperature for heating treatment, stirring is first performed for 8-12 min during the heating treatment, then the stirring is stopped and heat preservation is performed for 8-12 min, the temperature is lowered to the third heating temperature, 4.8-5.2 parts of elemental silicon is added, heating treatment is performed at the third heating temperature, stirring is first performed for 8-12 min during the heating treatment, then the stirring is stopped and heat preservation is performed for 8-12 min, and the molten composite metal is obtained. Or, 0.8-1.2 parts of metallic aluminum and 0.8-1.2 parts of metallic magnesium are added into 100 parts of the intermediate molten metal, the temperature is raised to the second heating temperature for heating treatment, stirring is first performed for 8-12 min during the heating treatment, then the stirring is stopped and heat preservation is performed for 8-12 min, the temperature is lowered to the third heating temperature, 4.8-5.2 parts of elemental silicon is added, heating treatment is performed at the third heating temperature, stirring is first performed for 8-12 min during the heating treatment, then the stirring is stopped and heat preservation is performed for 8-12 min, and the molten composite metal is obtained.

5. The method for preparing the metallic thermally conductive material according to claim 4, characterized in that, In the S1 step, the method for preparing the molten composite metal is as follows: 0.8-1.2 parts of metallic aluminum and 4.8-5.2 parts of elemental silicon are added into 100 parts of the intermediate molten metal, the temperature is raised to the second heating temperature for heating treatment, stirring is first performed for 8-12 min during the heating treatment, then the stirring is stopped and heat preservation is performed for 8-12 min, the temperature is lowered to the third heating temperature, 0.8-1.2 parts of metallic magnesium is added, heating treatment is performed at the third heating temperature, stirring is first performed for 8-12 min during the heating treatment, and heat preservation is performed for 8-12 min, and the molten composite metal is obtained.

6. The method for preparing the metallic thermally conductive material according to claim 1, characterized in that, The preparation method of the gallium-tin-indium alloy comprises the following steps: taking metallic gallium, metallic tin and metallic indium according to the mass percentage, heating the metallic gallium, the metallic tin and the metallic indium to 295-305 DEG C under an inert atmosphere, and heat preserving for 8-12 min to obtain the gallium-tin-indium alloy. And / or, the mass ratio of the gallium-tin-indium alloy to SiC in the molten composite metal is 7:

3.

7. The method for preparing the metallic thermally conductive material according to claim 6, characterized in that, The preparation method comprises the following steps: The gallium-tin-indium alloy contains 70% of gallium, 20% of tin and 10% of indium according to the mass percentage, and the metallic gallium, the metallic tin and the metallic indium are taken and heated to 300 DEG C under an inert atmosphere to obtain the gallium-tin-indium alloy; At the first heating temperature, 30 parts of SiC is added into 70 parts of the gallium-tin-indium alloy, stirring is performed for 20 min, and heat preservation is performed to obtain the intermediate molten metal; 1 part of metallic aluminum and 5 parts of elemental silicon are added into 100 parts of the intermediate molten metal, the temperature is raised to the second heating temperature for heating treatment, stirring is first performed for 10 min during the heating treatment, then the stirring is stopped and heat preservation is performed for 10 min, the temperature is lowered to the third heating temperature, 1 part of metallic magnesium is added, heating treatment is performed at the third heating temperature, stirring is first performed for 10 min during the heating treatment, then the stirring is stopped and heat preservation is performed for 10 min, and the molten composite metal is obtained. The molten composite metal is solidified at room temperature under a pressure of 15 to 30 MPa to obtain the metal heat conducting material.

8. A metal heat conducting material produced by the method of any one of claims 1 to 7.

9. A heat dissipating apparatus characterized by comprising: The metal heat conducting material of claim 8. The metal heat conducting material of claim 8.

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