Heat-conducting gasket and preparation method thereof

Abstract

The invention provides a heat-conducting gasket and a preparation method thereof, and belongs to the technical field of heat conduction. The heat conduction gasket comprises a first layer structure, a second layer structure and a third layer structure which are sequentially arranged in a stacked mode, the second layer structure comprises binary eutectic alloy, the microstructure of the binary eutectic alloy comprises a first phase and a second phase, the mass ratio of the first phase in the binary eutectic alloy is larger than that of the second phase in the binary eutectic alloy, and the mass ratio of the second phase in the binary eutectic alloy is larger than that of the first phase. The first phase is a solid solution phase. According to the heat-conducting gasket, the binary eutectic alloy and the low-temperature phase-change material are made into the three-layer sandwich structure, the middle layer comprises the binary eutectic alloy, the heat conductivity equivalent to that of pure metal can be achieved, and meanwhile the binary eutectic alloy has good flexibility; the layer structures on the two sides of the middle layer comprise the low-temperature phase-change materials, so that the heat-conducting gasket can be well compounded with a heating element and a heat dissipation element in an electronic device, and the heat-conducting gasket has the advantages of flexibility, high heat conductivity coefficient and low interface thermal resistance.

Description

Technical Field

[0001] The present application relates to the field of heat conduction technology, and in particular to a thermally conductive gasket and a preparation method thereof. Background Art

[0002] As the power density of electronic devices continues to increase, their heat generation also gradually increases, and the heat dissipation of electronic devices becomes increasingly important. The connection between the heating element and the heat dissipation element is not tight enough, resulting in a large amount of interface thermal resistance, which greatly reduces the heat dissipation effect of the device. Thermal interface materials can effectively solve the problem of interface heat dissipation. Currently, most thermal conductive gaskets on the market have a relatively low thermal conductivity coefficient. For metal thermal conductive gaskets such as indium sheets, although their thermal conductivity coefficient is high, their interface thermal resistance is still very high. Summary of the Invention

[0003] The present application provides a thermally conductive gasket and a preparation method thereof, which can have a higher thermal conductivity and a lower interface thermal resistance.

[0004] The embodiment of the present application is implemented as follows:

[0005] In a first aspect, the present application provides an example of a thermally conductive gasket, comprising: a first layer structure, a second layer structure and a third layer structure arranged in sequence, wherein the second layer structure comprises a binary eutectic alloy, the microstructure of the binary eutectic alloy comprises a first phase and a second phase, the mass proportion of the first phase in the binary eutectic alloy is greater than the mass proportion of the second phase in the binary eutectic alloy, the first phase is a solid solution phase, the first layer structure and / or the third layer structure comprise a low-temperature phase change material, and the melting point of the low-temperature phase change material is 40°C to 150°C.

[0006] In the above technical solution, the thermally conductive gasket of the present application is made into a three-layer sandwich structure by making a binary eutectic alloy and a low-temperature phase change material, wherein the middle layer includes the binary eutectic alloy, and the first phase with a larger mass proportion in the binary eutectic alloy is a solid solution phase. The solid solution phase has a crystal structure similar to that of pure metal, and can achieve thermal conductivity equivalent to that of pure metal. At the same time, the binary eutectic alloy has good flexibility; the layer structure on both sides of the middle layer includes low-temperature phase change material, which can enable the thermally conductive gasket to be better composited with the heating elements and heat dissipation elements in electronic devices. The thermally conductive gasket of the present application has flexibility, high thermal conductivity and low interface thermal resistance.

[0007] In some possible embodiments, the second phase is also a solid solution phase.

[0008] In the above technical solution, by making the second phase also a solid solution phase, the thermal conductivity of the second layer structure can be further improved, thereby improving the thermal conductivity coefficient of the thermally conductive gasket and reducing the interface thermal resistance of the thermally conductive gasket.

[0009] In some possible embodiments, the Young's modulus of the binary eutectic alloy is between 10 GPa and 85 GPa.

[0010] In the above technical solution, the present application makes the Young's modulus of the binary eutectic alloy within the above range, which is beneficial to reducing the flexibility of the binary eutectic alloy and thus improving the flexibility of the thermal pad.

[0011] In some possible embodiments, the thermal conductivity of the binary eutectic alloy is 50W to 500W.

[0012] In the above technical solution, the present application helps to reduce the thermal conductivity of the binary eutectic alloy by making the thermal conductivity of the binary eutectic alloy within the above range, thereby improving the thermal conductivity of the thermal conductive gasket and reducing the interface thermal resistance of the thermal conductive gasket.

[0013] In some possible embodiments, the binary eutectic alloy includes at least one of an InZn alloy, an InSn alloy, and a SnMg alloy; wherein the InZn alloy includes an In solid solution phase and a Zn solid solution phase, the InSn alloy includes an In solid solution phase and a Sn solid solution phase, and the SnMg alloy includes a Sn solid solution phase and a Mg2Sn phase.

[0014] In the above technical solution, the present application forms the second layer structure of the thermal gasket by selecting the above binary eutectic alloy as the raw material, which is beneficial to improving the thermal conductivity of the thermal gasket and reducing the interface thermal resistance of the thermal gasket.

[0015] In some possible embodiments, the mass proportion of the Zn element in the InZn alloy is 0.1 wt% to 10 wt%, and / or the mass proportion of the Sn element in the InSn alloy is 38 wt% to 48 wt%, and / or the mass proportion of the Mg element in the SnMg alloy is 0.1 wt% to 6 wt%.

[0016] In the above technical solution, when the mass proportion of the Zn element in the InZn alloy is within the above range, it is conducive to the formation of a binary eutectic alloy by the In element and the Zn element, and / or; when the mass proportion of the Sn element in the InSn alloy is within the above range, it is conducive to the formation of a binary eutectic alloy by the In element and the Sn element, and / or; when the mass proportion of the Mg element in the SnMg alloy is within the above range, it is conducive to the formation of a binary eutectic alloy by the Sn element and the Mg element.

[0017] In some possible embodiments, the low-temperature phase change material includes at least one of an InBiSn eutectic alloy, an InBi eutectic alloy, a GaInSnBi alloy, and a PCM phase change silicone grease.

[0018] In the above technical solution, the present application forms the first layer structure and the third layer structure of the thermal conductive gasket by selecting the above binary eutectic alloy as the raw material, which is conducive to enabling the thermal conductive gasket to achieve better composite with the heating elements and heat dissipation elements in the electronic device.

[0019] In some possible implementations, the thickness of the second layer structure is 0.05 mm to 0.2 mm.

[0020] In the above technical solution, the present application can better conduct the heat of the heating element to the heat dissipation element by making the thickness of the second layer structure within the above range.

[0021] In some possible embodiments, the thickness of the first layer structure and / or the thickness of the third layer structure is 10 μm to 50 μm.

[0022] In the above technical solution, the present application can fill the warping on the surface of the heating element while ensuring that there is no overflow, poor contact, and no impact on thermal conductivity by making the thickness of the first layer structure and / or the thickness of the third layer structure within the above range.

[0023] In the second aspect, the example of the present application provides a method for preparing a thermally conductive gasket, which includes: preparing a second layer structure, setting a low-temperature phase change material on both surfaces of the second layer structure by coating, atomization spraying or PVD film forming process to form a first layer structure and a third layer structure.

[0024] In the above technical scheme, the preparation method of the thermally conductive gasket of the present application is simple. The prepared thermally conductive gasket is made into a three-layer sandwich structure by making a binary eutectic alloy and a low-temperature phase change material, wherein the middle layer includes a binary eutectic alloy, and the first phase with a larger mass proportion in the binary eutectic alloy is a solid solution phase. The solid solution phase has a crystal structure similar to that of pure metal, and can achieve thermal conductivity equivalent to that of pure metal. At the same time, the binary eutectic alloy has good flexibility; the layer structure on both sides of the middle layer includes low-temperature phase change material, which can enable the thermally conductive gasket to be better composited with the heating elements and heat dissipation elements in electronic devices. The thermally conductive gasket of the present application has flexibility, high thermal conductivity and low interface thermal resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 This is a schematic structural diagram of a thermally conductive gasket according to an embodiment of the present application;

[0027] Figure 2 This is a schematic structural diagram of the application of a thermally conductive gasket according to an embodiment of the present application;

[0028] Figure 3 This is a photo of the thermally conductive gasket prepared in Example 1 of the present application.

[0029] Icon: 10-thermal pad; 100-first layer structure; 200-second layer structure; 300-third layer structure; 20-heat sink; 30-chip. DETAILED DESCRIPTION

[0030] The embodiments of the present application will be described in detail below with reference to the examples, but it will be understood by those skilled in the art that the following examples are merely illustrative of the present application and should not be considered as limiting the scope of the present application. In the examples, if specific conditions are not specified, the conditions are carried out according to conventional conditions or manufacturer recommendations. The reagents or instruments used are not specified by the manufacturer and are conventional products that can be purchased commercially.

[0031] The following is a detailed description of a thermally conductive pad and a preparation method thereof according to an embodiment of the present application:

[0032] See also Figure 1 The present application provides a thermally conductive gasket 10 , which includes: a first layer structure 100 , a second layer structure 200 and a third layer structure 300 that are stacked in sequence.

[0033] The second layer structure 200 includes a binary eutectic alloy.

[0034] A binary eutectic alloy refers to an alloy composed of two components that are completely miscible in the liquid state, but only partially miscible or completely insoluble in the solid state, and form an alloy with a specific microstructure through eutectic reaction.

[0035] The microstructure of a binary eutectic alloy includes a first phase and a second phase. The mass proportion of the first phase in the binary eutectic alloy is greater than the mass proportion of the second phase in the binary eutectic alloy, and the first phase is a solid solution phase.

[0036] The solid solution phase refers to an alloy phase in which solute atoms dissolve in the solvent lattice but still maintain the solvent crystal structure type. The solid solution phase has a crystal structure similar to that of pure metal and can achieve thermal conductivity comparable to that of pure metal.

[0037] Optionally, the second phase is also a solid solution phase.

[0038] By making the second phase also a solid solution phase, the thermal conductivity of the second layer structure 200 can be further improved, thereby increasing the thermal conductivity of the thermally conductive pad 10 and reducing the interface thermal resistance of the thermally conductive pad 10 .

[0039] Optionally, the Young's modulus of the binary eutectic alloy is 10 GPa to 85 GPa.

[0040] As an example, the Young's modulus of the binary eutectic alloy may be 10 GPa, 15 GPa, 20 GPa, 30 GPa, 40 GPa, 50 GPa, 60 GPa, 70 GPa, 80 GPa, 85 GPa, or a range of any two numbers therein.

[0041] The present application improves the flexibility of the thermally conductive gasket 10 by making the Young's modulus of the binary eutectic alloy within the above range, thereby enhancing the effective contact between the product and other interfaces.

[0042] Optionally, the thermal conductivity of the binary eutectic alloy is 50W to 500W.

[0043] As an example, the thermal conductivity of the binary eutectic alloy may be 50W, 100W, 150W, 200W, 250W, 300W, 350W, 400W, 450W, 500W, or a range of any two numbers therein.

[0044] The present application makes the thermal conductivity of the binary eutectic alloy within the above range, which is beneficial to improving the thermal conductivity of the thermally conductive gasket 10 and reducing the interface thermal resistance of the thermally conductive gasket 10 .

[0045] The binary eutectic alloy includes at least one of an InZn alloy, an InSn alloy, and a SnMg alloy.

[0046] Among them, the InZn alloy includes an In solid solution phase and a Zn solid solution phase. The mass proportion of the Zn element in the InZn alloy is 0.1wt% to 10wt%. In the InZn alloy, zinc atoms are dissolved in the face-centered tetragonal (FCT) lattice of indium in a substitutional form to form a single-phase solid solution. The solid solution contains other heterogeneous atoms. Due to lattice distortion, impurity scattering and interface effects, its electrical conductivity and thermal conductivity will be lower than that of single-element In metal.

[0047] As an example, the mass proportion of the Zn element in the InZn alloy can be 0.1wt%, 0.2wt%, 0.5wt%, 1wt%, 2wt%, 5wt%, 8wt%, 10wt% or a range of any two numbers therein.

[0048] When the mass proportion of the Zn element in the InZn alloy is within the above range, it is conducive to the formation of a binary eutectic alloy by the In element and the Zn element.

[0049] The InSn alloy includes an In solid solution phase and a Sn solid solution phase. The mass proportion of the Sn element in the InSn alloy is 38wt% to 48wt%. In the InSn alloy, the In solid solution and the Sn solid solution phase are staggered and evenly distributed.

[0050] As an example, the mass percentage of the Sn element in the InSn alloy may be 38 wt %, 40 wt %, 43 wt %, 45 wt %, 48 wt %, or a range of any two of these numbers.

[0051] When the mass ratio of the Sn element in the InSn alloy is within the above range, it is conducive to the formation of a binary eutectic alloy between the In element and the Sn element.

[0052] SnMg alloy includes Sn solid solution phase and Mg2Sn phase. The mass proportion of Mg element in SnMg alloy is 0.1wt% to 6wt%. In SnMg alloy, Sn solid solution is dominant, and MgSn phase is strengthened by nanoparticle dispersion.

[0053] As an example, the mass proportion of Mg element in the SnMg alloy can be 0.1wt%, 0.2wt%, 0.5wt%, 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt% or a range of any two numbers therein.

[0054] When the mass ratio of the Mg element in the SnMg alloy is within the above range, it is conducive to the formation of a binary eutectic alloy between the Sn element and the Mg element.

[0055] The present application selects the above-mentioned binary eutectic alloy as a raw material to form the second layer structure 200 of the thermally conductive gasket 10 , which is beneficial to improving the thermal conductivity of the thermally conductive gasket 10 and reducing the interface thermal resistance of the thermally conductive gasket 10 .

[0056] It should be noted that a small amount of multicomponent eutectic alloy may also exist in the second layer structure 200 .

[0057] Optionally, the thickness of the second layer structure 200 is 0.05 mm to 0.2 mm.

[0058] As an example, the thickness of the second layer structure 200 may be 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, or a range of any two numbers therein.

[0059] In the present application, by making the thickness of the second layer structure 200 within the above range, the heat of the heating element can be better conducted to the heat dissipation element.

[0060] The first layer structure 100 and / or the third layer structure 300 include a low-temperature phase change material, and the melting point of the low-temperature phase change material is 40° C. to 150° C.

[0061] It should be noted that either the first layer structure 100 or the third layer structure 300 may include the low-temperature phase change material, or both the first layer structure 100 and the third layer structure 300 may include the low-temperature phase change material.

[0062] As an example, the melting point of the low temperature phase change material may be 40° C., 50° C., 60° C., 80° C., 100° C., 120° C., 140° C., 150° C., or a range of any two of these values.

[0063] The warm phase change material includes at least one of InBiSn eutectic alloy, InBi eutectic alloy, GaInSnBi alloy and PCM phase change silicone grease.

[0064] Among them, InBiSn eutectic alloy is a low-melting-point eutectic alloy composed of three elements, indium (In), bismuth (Bi) and tin (Sn), in a specific ratio. The melting temperature of InBiSn eutectic alloy is usually lower than 100°C.

[0065] InBi eutectic alloy is a low-melting-point eutectic alloy formed by indium (In) and bismuth (Bi) in a specific proportion. Due to its low melting point, multiphase synergistic effect and controllable microstructure, InBi eutectic alloy shows broad application prospects in electronic packaging, energy storage and catalysis.

[0066] GaInSnBi alloy is a multi-element low-melting-point alloy composed of gallium (Ga), indium (In), tin (Sn) and bismuth (Bi). GaInSnBi alloy has significant advantages in thermal management and energy storage due to its ultra-low melting point, high latent heat and controllable microstructure.

[0067] PCM (Phase Change Material) phase change silicone grease is a thermal interface material based on phase change material. It combines the thermal conductivity of traditional silicone grease with the intelligent response characteristics of phase change material. It is solid at room temperature (similar to an elastic gasket or sheet), which is easy to store and install. When the temperature reaches the phase change point (usually 45-65°C), the material softens or liquefies, filling the microscopic gap between the heat sink and the chip, reducing the contact thermal resistance.

[0068] The present application selects the above binary eutectic alloy as raw material to form the first layer structure 100 and the third layer structure 300 of the thermal conductive gasket 10, which is conducive to enabling the thermal conductive gasket 10 to achieve better combination with the heating elements and heat dissipation elements in the electronic device.

[0069] Optionally, the thickness of the first layer structure 100 and / or the thickness of the third layer structure 300 is 10 μm to 50 μm.

[0070] As an example, the thickness of the first structure layer 100 and / or the thickness of the third structure layer 300 may be 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, or a range of any two thereof.

[0071] It should be noted that the thickness of the first layer structure 100 or the thickness of the third layer structure 300 may be 10 μm to 50 μm, or the thickness of the first layer structure 100 and the thickness of the third layer structure 300 may both be 10 μm to 50 μm. When the thickness of the first layer structure 100 and the thickness of the third layer structure 300 are both 10μm to 50μm, the thickness of the first layer structure 100 and the thickness of the third layer structure 300 can be the same or different. For example, the thickness of the first layer structure 100 and the thickness of the third layer structure 300 can both be 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm or 50μm; or the thickness of the first layer structure 100 is 10μm, and the thickness of the second layer structure 200 is 20μm; or the thickness of the first layer structure 100 is 10μm, and the thickness of the second layer structure 200 is 40μm; or the thickness of the first layer structure 100 is 40μm, and the thickness of the second layer structure 200 is 20μm; or the thickness of the first layer structure 100 is 50μm, and the thickness of the second layer structure 200 is 30μm.

[0072] The present application makes the thickness of the first layer structure 100 and / or the thickness of the third layer structure 300 within the above range, thereby filling the warping of the surface of the heating element and ensuring that there is no overflow, poor contact, and no impact on heat conduction.

[0073] See also Figure 2 The first layer structure 100 of the thermal conductive gasket 10 of the present application is used to combine with the heat sink 20 , and the third layer structure 300 is used to combine with the chip 30 , thereby conducting heat from the chip 30 to the heat sink 20 .

[0074] The thermally conductive gasket 10 of the present application is made into a three-layer sandwich structure by making a binary eutectic alloy and a low-temperature phase change material, wherein the middle layer includes the binary eutectic alloy, and the first phase with a larger mass proportion in the binary eutectic alloy is a solid solution phase. The solid solution phase has a crystal structure similar to that of pure metal, and can achieve thermal conductivity equivalent to that of pure metal. At the same time, the binary eutectic alloy has good flexibility; the layer structures on both sides of the middle layer include low-temperature phase change materials, which can enable the thermally conductive gasket 10 to be better composited with the heating elements and heat dissipation elements in electronic devices. The thermally conductive gasket 10 of the present application has flexibility, high thermal conductivity and low interface thermal resistance.

[0075] The present application also provides a method for preparing a thermally conductive gasket, which includes: preparing a second layer structure, and setting a low-temperature phase change material on both surfaces of the second layer structure by coating, atomization spraying or PVD film forming process to form a first layer structure and a third layer structure.

[0076] The preparation method of the thermally conductive gasket of the present application is simple. The prepared thermally conductive gasket is made into a three-layer sandwich structure by making a binary eutectic alloy and a low-temperature phase change material, wherein the middle layer includes the binary eutectic alloy, and the first phase with a larger mass proportion in the binary eutectic alloy is a solid solution phase. The solid solution phase has a crystal structure similar to that of pure metal, and can achieve thermal conductivity equivalent to that of pure metal. At the same time, the binary eutectic alloy has good flexibility; the layer structures on both sides of the middle layer include low-temperature phase change materials, which can enable the thermally conductive gasket to be better composited with the heating elements and heat dissipation elements in electronic devices. The thermally conductive gasket of the present application has flexibility, high thermal conductivity and low interface thermal resistance.

[0077] The following is a further detailed description of a thermally conductive gasket and a preparation method thereof of the present application in conjunction with embodiments.

[0078] Example 1

[0079] The present invention provides a thermally conductive pad and a method for preparing the same, comprising the following steps:

[0080] S1. Preparation of the second layer structure

[0081] The second layer structure is made of InZn alloy, the mass proportion of Zn element in the InZn alloy is 3.9wt%, and the thickness of the second layer structure is 0.2mm.

[0082] S2. Preparation of thermal pads

[0083] In is set on both surfaces of the second layer structure by coating 51 Bi 34 Sn 15 alloy, forming the first layer structure and the third layer structure on both surfaces of the second layer structure, the thickness of the first layer structure is 20 μm, the thickness of the third layer structure is 20 μm, and a thermal conductive gasket is obtained, such as Figure 3 shown.

[0084] Example 2

[0085] The present invention provides a thermally conductive pad and a method for preparing the same, comprising the following steps:

[0086] S1. Preparation of the second layer structure

[0087] The second layer structure is made of InZn alloy, the mass proportion of Zn element in the InZn alloy is 3.9wt%, and the thickness of the second layer structure is 0.2mm.

[0088] S2. Preparation of thermal pads

[0089] In is set on both surfaces of the second layer structure by coating 67 Bi 33alloy to form a first layer structure and a third layer structure on both surfaces of the second layer structure, the thickness of the first layer structure is 20 μm, and the thickness of the third layer structure is 20 μm, thereby obtaining a thermal conductive gasket.

[0090] Example 3

[0091] The present invention provides a thermally conductive pad and a method for preparing the same, comprising the following steps:

[0092] S1. Preparation of the second layer structure

[0093] The second layer structure is made of InZn alloy, the mass proportion of Zn element in the InZn alloy is 10wt%, and the thickness of the second layer structure is 0.2mm.

[0094] S2. Preparation of thermal pads

[0095] In is set on both surfaces of the second layer structure by coating 51 Bi 34 Sn 15 alloy to form a first layer structure and a third layer structure on both surfaces of the second layer structure, the thickness of the first layer structure is 20 μm, and the thickness of the third layer structure is 20 μm, thereby obtaining a thermal conductive gasket.

[0096] Example 4

[0097] The present invention provides a thermally conductive pad and a method for preparing the same, comprising the following steps:

[0098] S1. Preparation of the second layer structure

[0099] The second layer structure is made of InZn alloy, the mass proportion of Zn element in the InZn alloy is 10wt%, and the thickness of the second layer structure is 0.1mm.

[0100] S2. Preparation of thermal pads

[0101] In is set on both surfaces of the second layer structure by coating 51 Bi 34 Sn 15 alloy to form a first layer structure and a third layer structure on both surfaces of the second layer structure, the thickness of the first layer structure is 20 μm, and the thickness of the third layer structure is 20 μm, thereby obtaining a thermal conductive gasket.

[0102] Example 5

[0103] The present invention provides a thermally conductive pad and a method for preparing the same, comprising the following steps:

[0104] S1. Preparation of the second layer structure

[0105] The second layer structure is made of InSn alloy, the mass proportion of Sn element in the InSn alloy is 38wt%, and the thickness of the second layer structure is 0.2mm.

[0106] S2. Preparation of thermal pads

[0107] In is set on both surfaces of the second layer structure by coating 51 Bi 34 Sn 15 alloy to form a first layer structure and a third layer structure on both surfaces of the second layer structure, the thickness of the first layer structure is 20 μm, and the thickness of the third layer structure is 20 μm, thereby obtaining a thermal conductive gasket.

[0108] Example 6

[0109] The present invention provides a thermally conductive pad and a method for preparing the same, comprising the following steps:

[0110] S1. Preparation of the second layer structure

[0111] The second layer structure is made of SnMg alloy, the mass proportion of Mg element in the SnMg alloy is 1wt%, and the thickness of the second layer structure is 0.2mm.

[0112] S2. Preparation of thermal pads

[0113] In is set on both surfaces of the second layer structure by coating 51 Bi 34 Sn 15 alloy to form a first layer structure and a third layer structure on both surfaces of the second layer structure, the thickness of the first layer structure is 20 μm, and the thickness of the third layer structure is 20 μm, thereby obtaining a thermal conductive gasket.

[0114] Comparative Example 1

[0115] The comparative example of the present application provides a thermally conductive gasket, which is a high-purity indium sheet (99.99%), and the thickness of the indium sheet is 0.2 mm.

[0116] Comparative Example 2

[0117] The comparative example of the present application provides a thermally conductive gasket and a preparation method thereof, comprising the following steps:

[0118] S1. Preparation of the second layer structure

[0119] The second layer structure is made of a high-purity indium sheet (99.99%), and the thickness of the second layer structure is 0.2 mm.

[0120] S2. Preparation of thermal pads

[0121] In is set on both surfaces of the second layer structure by coating51 Bi 34 Sn 15 alloy to form a first layer structure and a third layer structure on both surfaces of the second layer structure, the thickness of the first layer structure is 20 μm, and the thickness of the third layer structure is 20 μm, thereby obtaining a thermal conductive gasket.

[0122] Comparative Example 3

[0123] The comparative example of the present application provides a thermally conductive gasket and a preparation method thereof, comprising the following steps:

[0124] S1. Preparation of the second layer structure

[0125] The second layer structure is made of a high-purity indium sheet (99.99%), and the thickness of the second layer structure is 0.2 mm.

[0126] S2. Preparation of thermal pads

[0127] In is set on both surfaces of the second layer structure by coating 67 Bi 33 alloy to form a first layer structure and a third layer structure on both surfaces of the second layer structure, the thickness of the first layer structure is 20 μm, and the thickness of the third layer structure is 20 μm, thereby obtaining a thermal conductive gasket.

[0128] Test Example 1

[0129] The interfacial thermal resistances of the thermally conductive pads of Examples 1 to 8 and Comparative Examples 1 to 3 were measured, and the results are shown in Table 1.

[0130] The test method of interface thermal resistance is as follows:

[0131] Test instrument: Taiwan Ruiling LW-9389 thermal resistance tester.

[0132] Sample preparation: Usually square (such as 26mm×26mm) with a flat surface.

[0133] Applied pressure: controlled at ~50 psi to simulate actual contact conditions.

[0134] Temperature control: The temperature difference between the upper and lower heat conducting columns is set (e.g. 50±5°C) to ensure that the heat flow passes vertically through the sample.

[0135] Data Acquisition: Precisely measure temperature using thermocouples or platinum resistance thermometers, and calculate heat flow using a heat flow meter or electric power meter. Measure the heat flux (Q) flowing through the sample, the temperature difference between the upper and lower surfaces (ΔT), and the contact area (S). Calculate thermal resistance using the formula R = ΔT / (Q·S).

[0136] Table 1 Thermal conductivity and interface thermal resistance of thermally conductive pads of Examples 1 to 8 and Comparative Examples 1 to 3

[0137]

[0138] From Examples 1 to 6 of the present application, it can be seen that the interface thermal resistance of the thermal conductive pad of the present application is 0.033°C*cm at 80°C and 50PSI. 2 / W~0.056℃*cm 2 / W.

[0139] From the comparison between comparative example 1 and embodiment 1, it can be seen that comparative example 1 uses a 0.02mm thick high-purity indium sheet as a thermal pad, and its interface thermal resistance is as high as 0.2℃*cm at 80℃&50PSI. 2 / W, which is much higher than the interface thermal resistance of the thermal conductive pad of Example 1 at 80°C and 50PSI.

[0140] From the comparison between Comparative Example 2 and Example 1, it can be seen that Comparative Example 2 uses a 0.02mm thick high-purity indium sheet as the second layer structure, and its interface thermal resistance at 80℃ and 50PSI is 0.041℃*cm 2 / W, and the interface thermal resistance of the thermal conductive pad of Example 1 at 80℃ & 50PSI is similar; from the comparison between Comparative Example 3 and Example 2, it can be seen that Comparative Example 3 uses a 0.02mm thick high-purity indium sheet as the second layer structure, and its interface thermal resistance at 80℃ & 50PSI is 0.04℃*cm 2 / W, and the interface thermal resistance at 80°C and 50 PSI is similar to that of the thermal pad of Example 2. The second layer structure of Examples 1 and 2 of the present application is a binary eutectic alloy. Binary eutectic alloy is not only cheaper than high-purity indium sheets, but also has a lower density, which makes the thermal pads of Examples 1 and 2 lighter.

[0141] The foregoing description is merely a specific embodiment of the present application and is not intended to limit the present application. Persons skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A thermally conductive pad, characterized in that: The thermal conductive gasket includes a first layer structure, a second layer structure and a third layer structure which are stacked in sequence, wherein the second layer structure includes a binary eutectic alloy, the microstructure of the binary eutectic alloy includes a first phase and a second phase, the mass proportion of the first phase in the binary eutectic alloy is greater than the mass proportion of the second phase in the binary eutectic alloy, the first phase is a solid solution phase, the first layer structure and / or the third layer structure include a low-temperature phase change material, and the melting point of the low-temperature phase change material is 40°C to 150°C.

2. The thermally conductive pad according to claim 1, wherein: The second phase is also a solid solution phase.

3. The thermally conductive pad according to claim 1, wherein: The Young's modulus of the binary eutectic alloy is 10 GPa to 85 GPa.

4. The thermally conductive pad according to claim 1, wherein: The thermal conductivity of the binary eutectic alloy is 50W to 500W.

5. The thermally conductive pad according to claim 1, wherein: The binary eutectic alloy includes at least one of an InZn alloy, an InSn alloy, and a SnMg alloy; The InZn alloy includes an In solid solution phase and a Zn solid solution phase, the InSn alloy includes an In solid solution phase and a Sn solid solution phase, and the SnMg alloy includes a Sn solid solution phase and a Mg2Sn phase.

6. The thermally conductive pad according to claim 5, characterized in that: The mass proportion of the Zn element in the InZn alloy is 0.1 wt% to 10 wt%, and / or the mass proportion of the Sn element in the InSn alloy is 38 wt% to 48 wt%, and / or the mass proportion of the Mg element in the SnMg alloy is 0.1 wt% to 6 wt%.

7. The thermally conductive pad according to claim 1, wherein: The low-temperature phase change material includes at least one of an InBiSn eutectic alloy, an InBi eutectic alloy, a GaInSnBi alloy and a PCM phase change silicone grease.

8. The thermally conductive pad according to claim 1, wherein: The thickness of the second layer structure is 0.05 mm to 0.2 mm.

9. The thermally conductive pad according to claim 1, wherein: The thickness of the first layer structure and / or the thickness of the third layer structure is 10 μm to 50 μm.

10. A method for preparing the thermally conductive gasket according to any one of claims 1 to 9, characterized in that: The preparation method of the thermal conductive gasket includes: preparing the second layer structure, and arranging the low-temperature phase change material on both surfaces of the second layer structure by coating, atomization spraying or PVD film forming process to form the first layer structure and the third layer structure.

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