Low-modulus high-thermal-conductivity indium-based thermal interface material and preparation method thereof

Abstract

The invention relates to the technical field of thermal interface materials, in particular to a low-modulus high-thermal-conductivity indium-based thermal interface material and a preparation method thereof. According to the thermal interface material, a matrix is indium, a reinforcing body is high-thermal-conductivity particles, phase change microcapsules and inorganic micro / nanowires, a ball-rod lap joint model is formed, and the thermal interface material comprises the following components in percentage by volume: 10%-40% of the high-thermal-conductivity particles, 0.1%-35% of the phase change microcapsules, 0.1%-10% of the inorganic micro / nanowires and the balance of indium. The invention also discloses a preparation method of the thermal interface material, which comprises the following steps: firstly, uniformly mixing the components according to the proportion, then carrying out vacuum warm pressing, and finally rolling the indium-based composite material subjected to the warm pressing into the required thickness. According to the low-modulus high-thermal-conductivity indium-based thermal interface material prepared through the method, isolated heat conduction components are connected through a ball-rod lap joint model, the number of heat conduction channels is increased, the heat flux is increased, phase change heat absorption can be achieved through the phase change microcapsules, the heat dissipation efficiency is further improved, the modulus of the phase change microcapsules is 55-73 MPa, and the thermal conductivity can reach 110-170 W / m.K.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal interface materials, and in particular to a low-modulus and high-thermal-conductivity indium-based thermal interface material and a preparation method thereof. Background Art

[0002] In recent years, electronic devices have rapidly advanced towards miniaturization, integration, and multifunctionality. This has led to a continuous increase in power density, which can cause localized overheating in devices, impacting their performance and lifespan. Thermal interface materials are typically used to fill the air gap between chips and heat sinks, establishing an effective heat conduction path, reducing contact thermal resistance, improving heat sink efficiency, and extending chip lifespan.

[0003] Currently, thermal interface materials are primarily divided into organic and metallic types. Common organic thermal interface materials typically consist of a composite system composed of a polymer, silicone oil, or resin matrix with a high-thermal-conductivity filler. Their thermal conductivity generally does not exceed 20W / m·K. Among metallic thermal interface materials, solder has a high modulus and is prone to cracking, while liquid metal can easily overflow and cause short circuits. Indium sheets, however, offer the advantages of low modulus, high thermal conductivity (86W / m·K), and resistance to overflow, making them a common thermal interface material for commercial high-power devices.

[0004] To further improve the heat transfer efficiency of indium sheets, existing research focuses on reducing the modulus of indium sheets and increasing their thermal conductivity. Chinese patents CN109957694A, CN109957695A, CN109957696A, and CN101022712A, among others, alloy indium with metals such as Ga, Sn, Zn, and Bi to produce a flexible thermal interface material with a melting point of 30°C-70°C, thereby reducing the modulus of the indium sheet. However, alloying reduces the thermal conductivity of the indium sheet. Chinese patent CN115847947A adds highly thermally conductive particles such as Al, Ag, and Cu to a pure indium matrix to prepare a composite material. Chinese patent CN102504769A composites indium with porous metal sheets such as Cu, Ag, Zn, Ti, Mg, Al, and Au to prepare a thermal interface material, thereby improving the thermal conductivity of the indium sheet. However, both methods increase the modulus of the indium sheet.

[0005] Therefore, it is necessary to develop an indium-based thermal interface material with both low modulus and high thermal conductivity. Summary of the Invention

[0006] Based on the problems of the prior art, the present invention proposes a low modulus and high thermal conductivity indium-based thermal interface material and a preparation method thereof. The specific scheme is as follows:

[0007] A low-modulus, high-thermal-conductivity indium-based thermal interface material comprises a matrix and a reinforcement, wherein the matrix is metallic indium, and the reinforcement is highly thermally conductive particles, phase-change microcapsules, and inorganic micro / nanowires. The phase-change microcapsules are core-shell structures comprising an inner core and an outer shell, wherein the inner core is a phase-change material, and the outer shell is an inorganic and / or organic material. The volume fraction of the highly thermally conductive particles accounts for 10%-40% of the indium-based thermal interface material, the volume fraction of the phase-change microcapsules accounts for 0.1%-35% of the indium-based thermal interface material, and the volume fraction of the inorganic micro / nanowires accounts for 0.1%-10% of the indium-based thermal interface material. The sum of the volume fractions of metallic indium, highly thermally conductive particles, phase-change microcapsules, and inorganic micro / nanowires is 100%, wherein the volume fractions of the phase-change microcapsules and inorganic micro / nanowires are not simultaneously zero. The highly thermally conductive particles are spherical or nearly spherical particles, and the highly thermally conductive particles, phase-change microcapsules, and inorganic micro / nanowires form a "ball-and-stick" overlap model. Preferably, the metallic indium is an indium flake.

[0008] Furthermore, the high thermal conductivity particles are one or more of diamond, silver, copper, and aluminum particles, and have a particle size of 0.1 μm-100 μm.

[0009] Furthermore, the surface of the high thermal conductivity particles is coated with a coating, wherein the coating is one or more of aluminum oxide, gold, silver, chromium, and nickel, and the coating is performed by electroplating, chemical plating, or vapor deposition.

[0010] Furthermore, the phase change microcapsules are one or more and have a particle size of 0.1 μm-100 μm.

[0011] Furthermore, in the phase-change microcapsules, the inorganic material is one or more of silicon dioxide, titanium dioxide, calcium carbonate, or calcium silicate; the organic material is one or more of urea-formaldehyde resin, melamine resin, polyurethane, polymethyl methacrylate, aromatic polyamide, polystyrene, polyurea resin, polyester resin, gelatin, gum arabic, or sodium alginate. The shell material can be a single material or a combination of two or more materials.

[0012] Furthermore, inorganic nanoparticles are additionally added to the shell, and the inorganic nanoparticles include one or more of platinum, silver, tin, zinc, aluminum, iron, calcium, and rare earth elements to improve the airtightness or thermal and hygroscopic stability of the shell.

[0013] Furthermore, the phase change material is a material having a phase change latent heat of 10-10000 J / g.

[0014] Furthermore, the phase change material is one or more of paraffin, higher fatty alcohol, higher fatty acid, hydrocarbon, polyether, aliphatic polyester, polyester ether, and normal alkane. The phase change material can be a single material or a combination of two or more materials.

[0015] Furthermore, the inorganic micro / nanowires are one or more of carbon nanotubes, carbon fibers, and metal micro / nanowires, and have a length of 0.01 μm to 100 μm, wherein the metal micro / nanowires are micro / nanowires of gold, silver, aluminum, copper, or zinc. The inorganic micro / nanowires can be a single material or a combination of two or more materials.

[0016] All micro / nanowires mentioned above refer to microwires, nanowires, or a mixture of microwires and nanowires.

[0017] A method for preparing the above-mentioned low modulus and high thermal conductivity indium-based thermal interface material comprises the following steps:

[0018] Step 1: Mix metal indium powder, high thermal conductivity particles, phase change microcapsules, and inorganic micro / nanowires uniformly according to volume ratio to obtain a mixed powder in a vacuum or inert gas protective atmosphere;

[0019] Step 2: vacuum pressing the mixed powder to prepare an indium-based composite material; the vacuum pressing is performed at a pressure of 5-40 MPa and a temperature of 80-140° C.;

[0020] Step 3: rolling the indium-based composite material to obtain an indium-based thermal interface material; the rolling temperature is 25-110° C., and the rolling rate is 1-5 m / min.

[0021] The size of the indium-based thermal interface material is determined by the size of the heating / heat dissipation device in the actual use scenario.

[0022] The beneficial effects of the present invention are:

[0023] (1) The present invention uses indium as the matrix to maintain the flexibility of the matrix, uses Al, Ag, Cu and other high thermal conductivity particles as reinforcement, and uses phase change microcapsules to replace a certain proportion of high thermal conductivity particles. The two characteristics of phase change materials absorbing latent heat during the phase change process and the low modulus of the phase change materials are utilized to achieve the purpose of high thermal conductivity and low modulus.

[0024] (2) In addition, inorganic micro / nanowires such as metal micro / nanowires, carbon nanotubes, and carbon fibers are used to replace a certain proportion of high thermal conductivity particles and phase change microcapsules to form a "ball-and-stick" lap model, connecting isolated thermal conductive components and increasing the number of thermal conduction pathways and heat flux, thereby achieving the purpose of high thermal conductivity;

[0025] In summary, the thermal interface material of the present invention comprises an indium matrix and a reinforcement (high thermal conductivity particles, phase change microcapsules, inorganic micro / nanowires), and has a high thermal conductivity of 110-170 W / m·K, which is higher than the thermal conductivity of pure indium of 86 W / m·K, and can significantly reduce the interface thermal resistance of the thermal interface material; at the same time, it retains a low compression modulus of 55-73 MPa, which is lower than the compressive elastic modulus of 70-112 MPa of the thermal interface material when the reinforcement is only metal particles; and the heat dissipation efficiency of the thermal interface material of the present invention is higher than that of pure indium, which can further reduce the temperature of the heat-generating device by 2-4°C. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The embodiments of the present invention are further described below with reference to the accompanying drawings, in which:

[0027] Figure 1 Shown are the structural schematics of indium-based thermal interface materials (left) and phase-change microcapsules (right);

[0028] Figure 2 shows an SEM image of the indium-based composite thermal interface material of Example 1;

[0029] Figure 3 The SEM image of the indium-based composite thermal interface material of Example 4 is shown.

[0030] 1- Indium metal matrix; 2- High thermal conductivity particles; 3- Phase change microcapsules; 4- Inorganic micro / nanowires; 5- Phase change material; 6- Shell. The rod-like structure is circled in the SEM image. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below through specific embodiments in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0032] Example 1

[0033] This embodiment relates to the field of thermal interface materials, more specifically, a low modulus and high thermal conductivity indium-based thermal interface material. The method includes the following steps:

[0034] (1) The volume ratios of the components of the low-modulus, high-thermal-conductivity indium-based composite thermal interface material in this embodiment are as follows: the high-thermal-conductivity particles are spherical copper particles with a particle size of 30 μm, the particle surface is coated with a silver layer, and the volume fraction of the copper particles is 20% of the indium-based composite material; the phase-change microcapsules are 20 μm in size, the shell material is Ce-doped silica, and the phase-change core material is paraffin wax, and the volume fraction of the phase-change microcapsules is 15% of the indium-based composite material; the inorganic micro / nanowires are carbon fibers with a length of 50 μm, and the volume fraction of the carbon fibers is 4% of the indium-based composite material; the remainder is indium. The entire powder mixing process is carried out in a vacuum environment.

[0035] (2) The vacuum temperature pressing pressure of the low modulus and high thermal conductivity indium-based composite thermal interface material in this embodiment is 35 MPa and the temperature is 140°C.

[0036] (3) The rolling temperature of the low modulus and high thermal conductivity indium-based composite thermal interface material in this embodiment is 70° C. and the rolling rate is 2 m / min.

[0037] The indium-based thermal interface material prepared in this example has a thermal conductivity of 153 W / m·K and a compression modulus of 58 MPa. The thermal conductivity was measured according to the method specified in GB / T 22588-2008, Flash Method for Determination of Thermal Diffusivity or Thermal Conductivity, and the compression modulus was measured according to GB / T 7314-2005, Room-Temperature Compression Test Method for Metallic Materials. The same method was used in Examples 2-12 and Comparative Example 1.

[0038] Example 2

[0039] This embodiment relates to the field of thermal interface materials, and more specifically to a low modulus and high thermal conductivity indium-based thermal interface material.

[0040] The following steps are involved:

[0041] (1) The volume ratios of the components of the low-modulus, high-thermal-conductivity indium-based composite thermal interface material in this embodiment are as follows: the high-thermal-conductivity particles are spherical copper particles with a particle size of 100 μm and diamond particles with a particle size of 35 μm, both of which are chromium-plated. The volume fractions of the copper particles and diamond particles are 15% and 10% of the indium-based composite material, respectively. The phase-change microcapsules are 0.1 μm in size, the shell material is urea-formaldehyde resin, and the phase-change core material is n-tetradecane. The volume fraction of the phase-change microcapsules is 10% of the indium-based composite material. The inorganic micro / nanowires are carbon nanotubes with a length of 75 μm. The volume fraction of the carbon nanotubes is 7% of the indium-based composite material. The remainder is indium. The entire powder mixing process is carried out under an argon atmosphere.

[0042] (2) The vacuum temperature pressing pressure of the low modulus and high thermal conductivity indium-based composite thermal interface material in this embodiment is 20 MPa and the temperature is 80°C.

[0043] (3) The rolling temperature of the low modulus and high thermal conductivity indium-based composite thermal interface material in this embodiment is 25° C. and the rolling rate is 1 m / min.

[0044] The thermal conductivity of the indium-based thermal interface material prepared in this embodiment is 160 W / m·K, and the compression modulus is 55 MPa.

[0045] Example 3

[0046] This embodiment relates to the field of thermal interface materials, and more specifically to a low modulus and high thermal conductivity indium-based thermal interface material.

[0047] The following steps are involved:

[0048] (1) The volume ratios of the components of the low modulus, high thermal conductivity, indium-based composite thermal interface material in this embodiment are as follows: the high thermal conductivity particles are spherical silver particles with a particle size of 0.1 μm and spherical aluminum particles with a particle size of 25 μm. The silver particles are coated with a nickel layer, and the aluminum particles are coated with an aluminum oxide layer. The volume fractions of the silver particles and aluminum particles are 12% and 17% of the indium-based composite material, respectively. The phase change microcapsules are 30 μm in size, the shell material is silicon dioxide, and the phase change core material is paraffin. The volume fraction of the phase change microcapsules is 15% of the indium-based composite material. The inorganic micro / nanowires are silver microwires with a length of 100 μm. The volume fraction of the silver microwires is 8% of the indium-based composite material. The remainder is indium. The entire powder mixing process is carried out in a vacuum environment.

[0049] (2) The vacuum temperature pressing pressure of the low modulus and high thermal conductivity indium-based composite thermal interface material in this embodiment is 40 MPa and the temperature is 120°C.

[0050] (3) The rolling temperature of the low modulus and high thermal conductivity indium-based composite thermal interface material in this embodiment is 50° C. and the rolling rate is 3 m / min.

[0051] The thermal conductivity of the indium-based thermal interface material prepared in this embodiment is 155 W / m·K, and the compression modulus is 56 MPa.

[0052] Example 4

[0053] This embodiment relates to the field of thermal interface materials, and more specifically to a low modulus and high thermal conductivity indium-based thermal interface material.

[0054] The following steps are involved:

[0055] (1) The volume ratios of the components of the low-modulus, high-thermal-conductivity indium-based composite thermal interface material in this embodiment are as follows: the high-thermal-conductivity particles are 60 μm diamond particles with a silver coating on the particle surface, and the volume fraction of the diamond particles is 40% of the indium-based composite material; the phase-change microcapsules are 40 μm in size, with a shell material of silicon dioxide and a phase-change core material of paraffin wax, and the volume fraction of the phase-change microcapsules is 1% of the indium-based composite material; the inorganic micro / nanowires are 50 μm in length carbon fibers and 18 μm in length gold microwires, and the volume fractions of the carbon fibers and gold microwires are 5% and 4% of the indium-based composite material, respectively; the remainder is indium. The entire powder mixing process is carried out under an argon atmosphere.

[0056] (2) The vacuum temperature pressing of the low modulus and high thermal conductivity indium-based composite thermal interface material in this embodiment is performed at a pressure of 35 MPa and a temperature of 135°C.

[0057] (3) The rolling temperature of the low modulus and high thermal conductivity indium-based composite thermal interface material in this embodiment is 110° C. and the rolling rate is 5 m / min.

[0058] The thermal conductivity of the indium-based thermal interface material prepared in this embodiment is 148 W / m·K, and the compression modulus is 65 MPa.

[0059] Example 5

[0060] This embodiment relates to the field of thermal interface materials, and more specifically to a low modulus and high thermal conductivity indium-based thermal interface material.

[0061] The following steps are involved:

[0062] (1) The volume ratios of the components of the low modulus, high thermal conductivity, indium-based composite thermal interface material in this embodiment are as follows: the high thermal conductivity particles are spherical aluminum particles with a particle size of 45 μm, the particle surface is coated with an aluminum oxide layer, and the volume fraction of the spherical aluminum particles is 12% of the indium-based composite material; there are two types of phase change microcapsules, one with a particle size of 65 μm, a shell material of gelatin, and a phase change core material of paraffin wax, and the volume fraction is 15% of the indium-based composite material; the other with a particle size of 35 μm, a shell material of polystyrene, and a phase change core material of paraffin wax and higher fatty acids, and the volume fraction is 20% of the indium-based composite material; the inorganic micro / nanowires are 18 μm long gold microwires, and the volume fraction of the gold microwires is 4% of the indium-based composite material, with the remainder being indium. The entire powder mixing process is carried out in a nitrogen environment.

[0063] (2) The vacuum temperature pressing pressure of the low modulus and high thermal conductivity indium-based composite thermal interface material in this embodiment is 10 MPa and the temperature is 110°C.

[0064] (3) The rolling temperature of the low modulus and high thermal conductivity indium-based composite thermal interface material in this embodiment is 100° C. and the rolling rate is 2 m / min.

[0065] The thermal conductivity of the indium-based thermal interface material prepared in this embodiment is 150 W / m·K, and the compression modulus is 61 MPa.

[0066] Example 6

[0067] This embodiment relates to the field of thermal interface materials, and more specifically to a low modulus and high thermal conductivity indium-based thermal interface material.

[0068] The following steps are involved:

[0069] (1) The volume ratios of the components of the low-modulus, high-thermal-conductivity indium-based composite thermal interface material in this embodiment are as follows: the high-thermal-conductivity particles are spherical aluminum particles with a particle size of 60 μm and diamond particles with a particle size of 75 μm. The surface of the diamond particles is plated with a chromium layer. The volume fractions of the aluminum particles and diamond particles are 5% and 15% of the indium-based composite material, respectively. The phase-change microcapsules are 50 μm in size, the shell material is calcium carbonate, and the phase-change core material is polyester ether. The volume fraction of the phase-change microcapsules is 12% of the indium-based composite material. The inorganic micro / nanowires are 30 μm in length zinc microwires. The volume fraction of the zinc microwires is 5% of the indium-based composite material, with the remainder being indium. The entire powder mixing process is carried out under an argon atmosphere.

[0070] (2) The vacuum temperature pressing pressure of the low modulus and high thermal conductivity indium-based composite thermal interface material in this embodiment is 25 MPa and the temperature is 80°C.

[0071] (3) The rolling temperature of the low modulus and high thermal conductivity indium-based composite thermal interface material in this embodiment is 40° C. and the rolling rate is 1 m / min.

[0072] The thermal conductivity of the indium-based thermal interface material prepared in this embodiment is 150 W / m·K, and the compression modulus is 65 MPa.

[0073] Example 7

[0074] This embodiment relates to the field of thermal interface materials, and more specifically to a low modulus and high thermal conductivity indium-based thermal interface material.

[0075] The following steps are involved:

[0076] (1) The volume ratios of the components of the low modulus, high thermal conductivity, indium-based composite thermal interface material in this embodiment are as follows: the high thermal conductivity particles are spherical silver particles with a particle size of 30 μm, the particle surface is coated with an aluminum oxide layer, and the volume fraction of the silver particles is 20% of the indium-based composite material; the phase change microcapsules are 60 μm in size, the shell material is titanium dioxide-doped sodium alginate, and the phase change core material is a polyester ether alloy, and the volume fraction of the phase change microcapsules is 10% of the indium-based composite material; the inorganic micro / nanowires are aluminum microwires with a length of 70 μm and silver microwires with a length of 30 μm, and the volume fractions of the aluminum microwires and silver microwires are 4% and 3% of the indium-based composite material, respectively; the remainder is indium. The entire powder mixing process is carried out in a vacuum environment.

[0077] (2) The vacuum temperature pressing pressure of the low modulus and high thermal conductivity indium-based composite thermal interface material in this embodiment is 35 MPa and the temperature is 140°C.

[0078] (3) The rolling temperature of the low modulus and high thermal conductivity indium-based composite thermal interface material in this embodiment is 70° C. and the rolling rate is 2 m / min.

[0079] The thermal conductivity of the indium-based thermal interface material prepared in this embodiment is 170 W / m·K, and the compression modulus is 55 MPa.

[0080] Example 8

[0081] This embodiment relates to the field of thermal interface materials, and more specifically to a low modulus and high thermal conductivity indium-based thermal interface material.

[0082] The following steps are involved:

[0083] (1) The volume ratios of the components of the low modulus, high thermal conductivity, indium-based composite thermal interface material in this embodiment are as follows: the high thermal conductivity particles are spherical silver particles with a particle size of 0.1 μm and spherical copper particles with a particle size of 35 μm. The silver particles are plated with a nickel coating, and the copper particles are plated with an aluminum oxide coating. The volume fractions of the silver particles and copper particles are 7% and 13% of the indium-based composite material, respectively. The phase change microcapsules are 30 μm in size, the shell material is calcium-doped melamine resin, and the phase change core material is n-hexadecane. The volume fraction of the phase change microcapsules is 10% of the indium-based composite material. The inorganic micro / nanowires are copper microwires with a length of 10 μm. The volume fraction of the copper microwires is 8% of the indium-based composite material. The remainder is indium. The entire powder mixing process is carried out under an argon atmosphere.

[0084] (2) The vacuum temperature pressing pressure of the low modulus and high thermal conductivity indium-based composite thermal interface material in this embodiment is 20 MPa and the temperature is 80°C.

[0085] (3) The rolling temperature of the low modulus and high thermal conductivity indium-based composite thermal interface material in this embodiment is 25° C. and the rolling rate is 1 m / min.

[0086] The thermal conductivity of the indium-based thermal interface material prepared in this embodiment is 128 W / m·K, and the compression modulus is 58 MPa.

[0087] Example 9

[0088] This embodiment relates to the field of thermal interface materials, and more specifically to a low modulus and high thermal conductivity indium-based thermal interface material.

[0089] The following steps are involved:

[0090] (1) The volume ratios of the components of the low-modulus, high-thermal-conductivity indium-based composite thermal interface material in this embodiment are as follows: the high-thermal-conductivity particles are spherical aluminum particles with a particle size of 50 μm, the particle surface is coated with a silver layer, and the volume fraction of the aluminum particles is 23% of the indium-based composite material; the phase-change microcapsules are 20 μm in size, the shell materials are gelatin and gum arabic, and the phase-change core material is polyethylene glycol, and the volume fraction of the phase-change microcapsules is 14% of the indium-based composite material; the inorganic micro / nanowires are zinc microwires with a length of 100 μm, and the volume fraction of the zinc microwires is 6% of the indium-based composite material; the remainder is indium. The entire powder mixing process is carried out in a vacuum environment.

[0091] (2) The vacuum temperature pressing pressure of the low modulus and high thermal conductivity indium-based composite thermal interface material in this embodiment is 35 MPa and the temperature is 140°C.

[0092] (3) The rolling temperature of the low modulus and high thermal conductivity indium-based composite thermal interface material in this embodiment is 70° C. and the rolling rate is 2 m / min.

[0093] The thermal conductivity of the indium-based thermal interface material prepared in this embodiment is 168 W / m·K, and the compression modulus is 60 MPa.

[0094] Comparative Example 1

[0095] This embodiment relates to the field of thermal interface materials, and more specifically to a low modulus and high thermal conductivity indium-based thermal interface material.

[0096] The following steps are involved:

[0097] (1) The low-modulus, high-thermal-conductivity indium-based composite thermal interface material in this embodiment has the following volume ratios: the high-thermal-conductivity particles are spherical copper particles with a particle size of 30 μm, coated with a silver layer, and the volume fraction of the copper particles is 20% of the indium-based composite material; the remainder is indium. The entire powder mixing process is performed in a vacuum environment.

[0098] (2) The vacuum temperature pressing pressure of the low modulus and high thermal conductivity indium-based composite thermal interface material in this embodiment is 35 MPa and the temperature is 140°C.

[0099] (3) The rolling temperature of the low modulus and high thermal conductivity indium-based composite thermal interface material in this embodiment is 70° C. and the rolling rate is 2 m / min.

[0100] The thermal conductivity of the indium-based thermal interface material prepared in this embodiment is 98 W / m·K, and the compression modulus is 80 MPa.

[0101] Some exemplary embodiments of the present invention are described above. It will be understood that the above embodiments are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention. The features in these embodiments can be recombined in an appropriate manner, and the solutions obtained thereby are still within the scope of protection claimed by the present invention. Based on the above embodiments, all other embodiments obtained by those skilled in the art without making creative work, that is, all modifications, equivalent substitutions and improvements made within the spirit and principles of this application, fall within the scope of protection claimed by the present invention.

Claims

1. A low modulus and high thermal conductivity indium-based thermal interface material, characterized in that: The invention comprises a matrix and a reinforcement, wherein the matrix is metallic indium, the reinforcement is high thermal conductivity particles, phase change microcapsules, and inorganic micro / nanowires, wherein the phase change microcapsules are a core-shell structure comprising an inner core and an outer shell, the inner core is a phase change material, and the outer shell is an inorganic material and / or an organic material; and the volume fractions of the components are as follows: 10%-40% high thermal conductivity particles, 0.1-35% phase change microcapsules, 0.1-10% inorganic micro / nanowires, and the balance metallic indium.

2. The low modulus and high thermal conductivity indium-based thermal interface material according to claim 1, characterized in that: The high thermal conductivity particles are one or more of diamond, silver, copper, and aluminum particles, and have a particle size of 0.1 μm-100 μm.

3. The low modulus and high thermal conductivity indium-based thermal interface material according to claim 2, characterized in that: The surface of the high thermal conductivity particles is coated with a coating, and the coating is one or more of aluminum oxide, gold, silver, chromium, and nickel.

4. The low modulus and high thermal conductivity indium-based thermal interface material according to claim 1, characterized in that: The phase change microcapsules are one or more and have a particle size of 0.1 μm-100 μm.

5. The low modulus and high thermal conductivity indium-based thermal interface material according to claim 1, characterized in that: In the phase change microcapsules, the inorganic material is one or more of silicon dioxide, titanium dioxide, calcium carbonate or calcium silicate; the organic material is one or more of urea-formaldehyde resin, melamine resin, polyurethane, polymethyl methacrylate, aromatic polyamide, polystyrene, polyurea resin, polyester resin, gelatin, gum arabic or sodium alginate.

6. The low modulus and high thermal conductivity indium-based thermal interface material according to claim 5, characterized in that: Inorganic nanoparticles are additionally added to the shell of the phase-change microcapsule, and the inorganic nanoparticles include one or more of platinum, silver, tin, zinc, aluminum, iron, calcium, and rare earth elements.

7. The low modulus and high thermal conductivity indium-based thermal interface material according to claim 1, characterized in that: The phase change material is a material with a phase change latent heat of 10-10000 J / g.

8. The low modulus and high thermal conductivity indium-based thermal interface material according to claim 7, characterized in that: The phase change material is one or more of paraffin, higher fatty alcohol, higher fatty acid, hydrocarbon, polyether, aliphatic polyester, polyester ether, and normal alkane.

9. The low modulus and high thermal conductivity indium-based thermal interface material according to claim 1, characterized in that: The inorganic micro / nanowires are one or more of carbon nanotubes, carbon fibers, and metal micro / nanowires, and have a length of 0.01 μm-100 μm, wherein the metal micro / nanowires are micro / nanowires of gold, silver, aluminum, copper, or zinc.

10. A method for preparing a low modulus and high thermal conductivity indium-based thermal interface material according to any one of claims 1 to 9, characterized in that: The following steps are involved: Step 1: Mix metal indium powder, high thermal conductivity particles, phase change microcapsules, and inorganic micro / nanowires uniformly according to volume ratio to obtain a mixed powder in a vacuum or inert gas protective atmosphere; Step 2: vacuum pressing the mixed powder to prepare an indium-based composite material; the vacuum pressing is performed at a pressure of 5-40 MPa and a temperature of 80-140° C.; Step 3: rolling the indium-based composite material to obtain an indium-based thermal interface material; the rolling temperature is 25-110° C., and the rolling rate is 1-5 m / min.

Images