A highly thixotropic, low thermal resistance, and ultra-long life thermal conductive silicone grease and its preparation method

Abstract

The present invention discloses a highly thixotropic, low thermal resistance and ultra-long life thermal conductive silicone grease and its preparation method. By the compatibility of silicone oils with different degrees of branching and different end groups, a compound silicone oil with higher wettability and lubricity is obtained, reducing the friction between powders and increasing the powder filling rate; by adding nano-ABS microsphere powders, on the one hand, the thixotropy of the material is improved, and on the other hand, the high-temperature stability and shape retention ability of the thermal conductive silicone grease are improved by utilizing the characteristics of high-temperature softening and swelling of ABS at high temperatures; by adding Ce element to the Al matrix, due to the low electronegativity of Ce, more metals are provided for Al, increasing the electron density of the conduction band; at the same time, the addition of Ce can modulate the electronic structure of Al, further expanding the s-band and p-band of Al, improving the mobility of conduction band electrons, so that AlCe has a higher thermal conductivity than pure Al.

Description

Technical Field

[0001] The invention relates to the field of new materials, and in particular to a high-thixotropic, low-thermal-resistance, ultra-long-life thermal conductive silicone grease and a preparation method thereof. Background Art

[0002] In today's era of rapid development of electronic technology, electronic devices continue to move towards miniaturization, high integration and high performance. This causes the power density per unit area of electronic components to rise sharply. If the heat cannot be dissipated in time, the electronic components will suffer from serious problems such as performance degradation, shortened lifespan or even failure due to overheating. Therefore, the heat dissipation problem has become a key bottleneck restricting the further development of electronic devices.

[0003] At present, the mainstream heat dissipation method uses a metal heat sink to directly contact the heat source, thereby directing the heat from the heat source to the metal heat sink. However, due to the microscopic unevenness between the surface of the electronic component and the heat sink, the actual contact area between the two usually only accounts for a small part of the theoretical contact area, and there are a large number of air gaps on the contact surface. Air is a poor conductor of heat, which greatly hinders the conduction of heat. In order to solve this problem, thermal conductive silicone grease came into being. It is a highly thermally conductive insulating silicone material that can fill these tiny air gaps. With its good fluidity and thermal conductivity, it forms a tighter and lower thermal resistance heat conduction channel between the heat source and the heat sink, thereby significantly improving the heat dissipation efficiency and ensuring the stable and reliable operation of electronic equipment. However, the thermal conductivity of traditional thermal conductive silicone grease is difficult to break through, and the thermal resistance remains high, making it increasingly unable to meet the heat dissipation needs of high-power electronic components. In addition, the current thermal grease products have the following problems that need to be solved: (1) The silicone grease itself has no fixed shape and is prone to flow, overflow or deform due to external forces during use, affecting its effective filling and heat conduction effect between the heating element and the heat dissipation component, especially when the device is vibrated or tilted. (2) In a long-term high temperature environment, it is easy to dry, harden, and age, resulting in a decrease in thermal conductivity, which greatly reduces the heat dissipation effect of the device and further affects the performance and life of the device; and in the long-term use process, the migration, decomposition, and volatilization of the liquid in the silicone grease will also further increase the thermal resistance and reduce the heat transfer effect. Summary of the invention

[0004] Purpose of the invention: The technical problem to be solved by the present invention is to provide a thermally conductive silicone grease with high thixotropy, low thermal resistance and ultra-long life in view of the deficiencies in the prior art, so as to solve the problems of easy deformation and insufficient aging resistance of the existing silicone grease itself, and further improve its thermal conductivity.

[0005] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is as follows:

[0006] A highly thixotropic, low thermal resistance, and ultra-long-life thermal conductive silicone grease, characterized by comprising the following components in mass percentage:

[0007] Micron-sized AlCe microspheres 65 - 87 wt%;

[0008] AlN nanospheres 6 - 26 wt%;

[0009] Acrylonitrile-butadiene-styrene nanoplastic microspheres 2 - 4 wt%;

[0010] Vinyl-terminated silicone oil 2 - 2.5 wt%;

[0011] Methyl-terminated silicone oil 0.5 - 0.75 wt%;

[0012] Hydroxyl-terminated silicone oil 0.5 - 0.75 wt%;

[0013] Polyglycerol-10 laurate 1 - 2 wt%.

[0014] Further, in the micron-sized AlCe microspheres, the mass ratio of Ce element to Al element is 0.02 - 0.025, preferably 0.022.

[0015] Further, the micron-sized AlCe microspheres include AlCe microspheres with a particle size of 4 - 6 microns, AlCe microspheres with a particle size of 1 - 3 microns, and AlCe microspheres with a particle size of 0.3 - 0.5 microns.

[0016] Preferably, the AlCe microspheres with a particle size of 4 - 6 microns account for 40 wt% - 50 wt% of the total mass of the thermal conductive silicone grease,

[0017] the AlCe microspheres with a particle size of 1 - 3 microns account for 20 wt% - 30 wt% of the total mass of the thermal conductive silicone grease,

[0018] the AlCe microspheres with a particle size of 0.3 - 0.5 microns account for 5 wt% - 7 wt% of the total mass of the thermal conductive silicone grease.

[0019] Further, the particle size of the AlN nanospheres is 100 - 300 nanometers.

[0020] Further, the particle size of the acrylonitrile-butadiene-styrene nanoplastic microspheres is 50 - 100 nanometers.

[0021] Further, the dynamic viscosity of the vinyl-terminated silicone oil is 150 cst, and the branching factor is 0.3 - 0.5.

[0022] Further, the dynamic viscosity of the methyl-terminated silicone oil is 100 cst, and the branching factor is 0.7 - 0.9.

[0023] Furthermore, the hydroxyl-terminated silicone oil has a dynamic viscosity of 300 cst and a branching factor of 0.4-0.6.

[0024] Furthermore, the present invention also claims a method for preparing the above-mentioned high thixotropic, low thermal resistance and ultra-long life thermal conductive silicone grease, comprising the following steps:

[0025] (1) Mixing vinyl-terminated silicone oil and methyl-terminated silicone oil, stirring at a speed of 300-500 rpm, and continuously stirring for 10-30 minutes to obtain a first mixed solution;

[0026] (2) Mixing the hydroxyl-terminated silicone oil and polyglycerol-10 laurate, stirring at a speed of 300-500 rpm, and continuously stirring for 10-30 minutes to obtain a second mixed solution;

[0027] (3) adding acrylonitrile-butadiene-styrene plastic microspheres to the second mixed solution obtained in step (2), heating to 60-80° C., 300-500 rpm, stirring continuously for 1-3 hours, and cooling to room temperature to obtain a first mixture;

[0028] (4) adding the first mixed solution obtained in step (1) to the first mixture obtained in step (3), and stirring at a speed of 300 to 500 rpm for 20 to 40 minutes to obtain a second mixture;

[0029] (5) adding micron-sized AlCe microspheres and AlN nano-microspheres to cyclohexane in proportion, and stirring the mixture in a sealed state for 1 to 3 hours at a stirring speed of 100 to 300 rpm to obtain a third mixture, wherein the mass ratio of the sum of the microspheres to the mass of cyclohexane is 3 to 4:1;

[0030] (6) Add the second mixture to the third mixture obtained in step (5) in proportion, seal and stir at a speed of 700-900 rpm for 5-15 minutes to obtain a fourth mixture;

[0031] (7) opening the lid of the container containing the fourth mixture, removing the sealing state, raising the temperature to 40-50° C., evacuating the pressure to below 2 kPa, and maintaining the pressure for 2-4 hours to remove the cyclohexane, and cooling to room temperature to obtain a fifth mixture;

[0032] (8) The fifth mixture obtained in step (7) is subjected to vacuum degassing at room temperature with a stirring speed of 1000-1200 rpm, a vacuum degree of less than 1 kPa, and a degassing time of 10-20 minutes to obtain the fifth mixture. Beneficial Effects

[0033] (1) By the compatibility of silicone oils with different degrees of branching and different end groups, a compound silicone oil with higher wettability and lubricity is obtained, reducing the friction between powders and increasing the powder filling rate. On the other hand, through the silicone oil compatibility described in the present invention, by the entanglement of molecular chains and the interaction of end groups between silicone oils with different degrees of branching and different end groups, good shape retention ability at high temperatures can be obtained. By adding nano-ABS microsphere powders, on the one hand, the thixotropy of the material is improved, and on the other hand, by utilizing the characteristics of high-temperature softening and swelling of ABS at high temperatures, the high-temperature stability and shape retention ability of the thermal conductive grease are improved; by adding Ce element to the Al matrix, due to the low electronegativity of Ce, more metals are provided for Al, increasing the electron density of the conduction band; at the same time, the addition of Ce can modulate the electronic structure of Al, making the s-band and p-band of Al further expand, improving the mobility of conduction band electrons; the above two effects make AlCe have a higher thermal conductivity than pure Al.

[0034] (2) The present invention provides a controllable preparation of a high-thixotropy, low-thermal-resistance, and ultra-long-life thermal conductive grease through the selection of components and ratios and a preparation process with strict parameter control. The obtained thermal conductive grease has a thixotropy index greater than 15 and a thermal resistance (40 psi) less than 0.025 cm 2 .K / W; after 1000 hours of high-temperature aging at 150 ℃ the change rate of the thermal resistance (40 psi) is less than 3%, and after 5000 hours of high-temperature aging at 150 ℃ the change rate of the thermal resistance (40 psi) is less than 5%. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The following further describes the present invention in detail with reference to the drawings and specific embodiments, and the above and / or other advantages of the present invention will become clearer.

[0036] Figure 1 is the change of the thermal resistance data of the thermal conductive grease in Example 1 at 150 o °C over time. SPECIFIC EMBODIMENTS

[0037] The present invention can be better understood according to the following embodiments.

[0038] In the following examples, AlCe0.022 microspheres mean that in the microspheres, the mass ratio of Ce element to Al element is 0.022. AlCe0.023 microspheres mean that in the microspheres, the mass ratio of Ce element to Al element is 0.023. AlCe0.025 microspheres mean that in the microspheres, the mass ratio of Ce element to Al element is 0.025. Example 1

[0039] A highly thixotropic, low thermal resistance and ultra-long life thermal conductive silicone grease: The composition includes 40 wt% of AlCe0.022 microspheres with a particle size of 4 - 5 microns, 20 wt% of AlCe0.022 microspheres with a particle size of 1 - 2 microns, 5 wt% of AlCe0.022 microspheres with a particle size of 0.3 - 0.4 microns, 26 wt% of AlN microspheres with a particle size of 100 - 200 nanometers, 4 wt% of acrylonitrile-butadiene-styrene (ABS) plastic microspheres with a particle size of 50 - 75 nanometers, 2 wt% of vinyl-terminated silicone oil with a dynamic viscosity of 150 cst and a branching factor g of 0.3, 0.5 wt% of methyl-terminated silicone oil with a dynamic viscosity of 100 cst and a branching factor g of 0.7, 0.5 wt% of hydroxyl-terminated silicone oil with a dynamic viscosity of 300 cst and a branching factor g of 0.4, and 2 wt% of polyglycerol-10 laurate.

[0040] It is prepared by the following steps:

[0041] (1) Mix the vinyl-terminated silicone oil with a dynamic viscosity of 150 cst and a branching factor g of 0.3 and the methyl-terminated silicone oil with a dynamic viscosity of 100 cst and a branching factor g of 0.7 in proportion, with a stirring speed of 300 rpm, and continuously stir for 10 minutes to obtain the first mixture;

[0042] (2) Mix the hydroxyl-terminated silicone oil with a dynamic viscosity of 300 cst and a branching factor g of 0.4 and polyglycerol-10 laurate in proportion, with a stirring speed of 300 rpm, and continuously stir for 10 minutes to obtain the second mixture;

[0043] (3) Add the acrylonitrile-butadiene-styrene (ABS) plastic microspheres with a particle size of 50 - 75 nanometers to the second mixture obtained in step (2), heat to 60 °C, stir at 300 rpm for 1 hour, and cool to room temperature to obtain the first mixture;

[0044] (4) Add the first mixture obtained in step (1) to the first mixture obtained in step (3), and stir at a speed of 300 revolutions per minute for 20 minutes to obtain the second mixture;

[0045] (5) Add the AlCe0.022 microspheres with a particle size of 4 - 5 microns, the AlCe0.022 microspheres with a particle size of 1 - 2 microns, the AlCe0.022 microspheres with a particle size of 0.3 - 0.4 microns, and the AlN microspheres with a particle size of 100 - 200 nanometers to cyclohexane in proportion, cover and seal, and stir for 1 hour at a stirring speed of 100 rpm to obtain the third mixture; the mass ratio of the sum of the masses of each microsphere to the mass of cyclohexane is 3:1;

[0046] (6) Add the second mixture to the third mixture obtained in step (5) in proportion, cover and seal, stir at a stirring speed of 700 rpm for 5 minutes to obtain the fourth mixture;

[0047] (7) Unseal the container filled with the fourth mixture, heat it up to 40 °C, evacuate and reduce the pressure to 2 kPa, and maintain for 2 hours. After cooling to room temperature, a fifth mixture is obtained;

[0048] (8) Load the fifth mixture obtained in step (7) into a planetary vacuum stirring and degassing machine for vacuum degassing at room temperature. The stirring speed is 1000 rpm, the vacuum degree is 1 kPa, and the degassing time is 10 minutes to obtain a highly thixotropic, low thermal resistance, and ultra-long life thermal conductive silicone grease.

[0049] After testing, at 25 °C, the thixotropic index (7# rotor, η 10rpm / η 1rpm ) of this thermal conductive silicone grease is 15.6; the thermal resistance (40 psi) is 0.024 cm 2 .K / W; after 1000 hours of high-temperature aging at 150 °C, the change rate of the thermal resistance (40 psi) is 2.9%, and after 5000 hours of high-temperature aging at 150 °C, the change rate of the thermal resistance (40 psi) is 5.0%. Example 2

[0050] A highly thixotropic, low thermal resistance, and ultra-long life thermal conductive silicone grease: The composition includes 50 wt% of AlCe0.025 microspheres with a particle size of 5 - 6 microns, 30 wt% of AlCe0.025 microspheres with a particle size of 2 - 3 microns, 7 wt% of AlCe0.025 microspheres with a particle size of 0.4 - 0.5 microns, 6 wt% of AlN microspheres with a particle size of 200 - 300 nm, 2 wt% of acrylonitrile-butadiene-styrene (ABS) plastic microspheres with a particle size of 75 - 100 nm, 2.5 wt% of vinyl-terminated silicone oil with a dynamic viscosity of 150 cst and a branching factor g of 0.5, 0.75 wt% of methyl-terminated silicone oil with a dynamic viscosity of 100 cst and a branching factor g of 0.9, 0.75 wt% of hydroxyl-terminated silicone oil with a dynamic viscosity of 300 cst and a branching factor g of 0.6, and 1 wt% of polyglycerol-10 laurate

[0051] It is prepared by the following steps:

[0052] (1) Mix the vinyl-terminated silicone oil with a dynamic viscosity of 150 cst and a branching factor g of 0.5 and the methyl-terminated silicone oil with a dynamic viscosity of 100 cst and a branching factor g of 0.9 in proportion, and stir at a speed of 500 rpm for 30 minutes to obtain a first mixed solution;

[0053] (2) Mix the hydroxyl-terminated silicone oil with a dynamic viscosity of 300 cst and a branching factor g of 0.6 and polyglycerol-10 laurate in proportion, and stir at a speed of 500 rpm for 30 minutes to obtain a second mixed solution;

[0054] (3) Adding acrylonitrile-butadiene-styrene (ABS) plastic microspheres with a particle size of 75 to 100 nanometers to the second mixed solution obtained in step (2), heating to 80° C., 500 rpm, stirring continuously for 3 hours, and cooling to room temperature to obtain a first mixture;

[0055] (4) adding the first mixed solution obtained in step (1) to the first mixture obtained in step (3), and stirring at a speed of 500 rpm for 40 minutes to obtain a second mixture;

[0056] (5) Adding AlCe0.025 microspheres with a particle size of 5 to 6 μm, AlCe0.022 microspheres with a particle size of 2 to 3 μm, AlCe0.025 microspheres with a particle size of 0.4 to 0.5 μm, and AlN microspheres with a particle size of 200 to 300 nm to cyclohexane in proportion, sealing the mixture, and stirring for 3 hours at a stirring speed of 300 rpm to obtain a third mixture; wherein the mass ratio of the sum of the microspheres to the mass of cyclohexane is 4:1;

[0057] (6) Add the second mixture to the third mixture obtained in step (5) in proportion, cover and seal, and stir at a speed of 900 rpm for 15 minutes to obtain a fourth mixture;

[0058] (7) opening the lid of the container containing the fourth mixture, removing the sealing state, heating it to 50° C., evacuating the pressure to 2 kPa, and maintaining the pressure for 4 hours, and cooling it to room temperature to obtain a fifth mixture;

[0059] (8) The fifth mixture obtained in step (7) is placed in a planetary vacuum stirring degassing machine for vacuum degassing at room temperature, with a stirring speed of 1200 rpm, a vacuum degree of 1 kPa, and a degassing time of 20 minutes, thereby obtaining a high thixotropic, low thermal resistance, and ultra-long life thermal conductive silicone grease.

[0060] After testing, under 25℃, the thixotropic index of the thermal grease (7# rotor, η 10rpm / η 1rpm ) is 17.7; thermal resistance (40psi) is 0.016cm 2 .K / W, the change rate of thermal resistance (40psi) after aging at 150℃ for 1000 hours is 1.5%, and the change rate of thermal resistance (40psi) after aging at 150℃ for 5000 hours is 2.9%. Example 3

[0061] A high thixotropic, low thermal resistance, and ultra-long-life thermal conductive silicone grease: The composition includes 45 wt% of AlCe0.023 microspheres with a particle size of 4.5 - 5.5 microns, 25 wt% of AlCe0.023 microspheres with a particle size of 1.5 - 2.5 microns, 6 wt% of AlCe0.023 microspheres with a particle size of 0.35 - 0.45 microns, 16 wt% of AlN microspheres with a particle size of 150 - 250 nanometers, 3 wt% of acrylonitrile-butadiene-styrene (ABS) plastic microspheres with a particle size of 65 - 90 nanometers, 2.25 wt% of vinyl-terminated silicone oil with a dynamic viscosity of 150 cst and a branching factor g of 0.4, 0.6 wt% of methyl-terminated silicone oil with a dynamic viscosity of 100 cst and a branching factor g of 0.8, 0.65 wt% of hydroxyl-terminated silicone oil with a dynamic viscosity of 300 cst and a branching factor g of 0.5, and 1.5 wt% of polyglycerol-10 laurate

[0062] It is prepared by the following steps:

[0063] (1) Mix the vinyl-terminated silicone oil with a dynamic viscosity of 150 cst and a branching factor g of 0.4 and the methyl-terminated silicone oil with a dynamic viscosity of 100 cst and a branching factor g of 0.8 in proportion, stir at a speed of 400 rpm, and continuously stir for 20 minutes to obtain the first mixture;

[0064] (2) Mix the hydroxyl-terminated silicone oil with a dynamic viscosity of 300 cst and a branching factor g of 0.5 and polyglycerol-10 laurate in proportion, stir at a speed of 400 rpm, and continuously stir for 20 minutes to obtain the second mixture;

[0065] (3) Add the acrylonitrile-butadiene-styrene (ABS) plastic microspheres with a particle size of 65 - 90 nanometers to the second mixture obtained in step (2), heat up to 70 °C, stir at 400 rpm, and continuously stir for 2 hours. After cooling to room temperature, obtain the first mixture;

[0066] (4) Add the first mixture obtained in step (1) to the first mixture obtained in step (3), stir at a speed of 400 revolutions per minute for 30 minutes to obtain the second mixture;

[0067] (5) Add the AlCe0.023 microspheres with a particle size of 4.5 - 5.5 microns, the AlCe0.023 microspheres with a particle size of 1.5 - 2.5 microns, the AlCe0.023 microspheres with a particle size of 0.35 - 0.45 microns, and the AlN microspheres with a particle size of 150 - 250 nanometers to cyclohexane in proportion, cover and seal, stir for 2 hours, and stir at a speed of 200 rpm to obtain the third mixture; the mass ratio of the sum of the masses of each microsphere to the mass of cyclohexane is 3.5:1;

[0068] (6) Add the second mixture to the third mixture obtained in step (5) in proportion, cover and seal it, and stir at a stirring speed of 800 rpm for 10 minutes to obtain a fourth mixture;

[0069] (7) Open the lid of the container containing the fourth mixture to relieve the sealed state, heat it up to 45 °C, evacuate and reduce the pressure to 2 kPa, and maintain for 3 hours. After cooling to room temperature, a fifth mixture is obtained;

[0070] (8) Load the fifth mixture obtained in step (7) into a planetary vacuum stirring and degassing machine for vacuum degassing at room temperature. The stirring speed is 1100 rpm, the vacuum degree is 1 kPa, and the degassing time is 15 minutes to obtain a highly thixotropic, low thermal resistance, and ultra-long life thermal conductive silicone grease.

[0071] After testing, at 25 °C, the thixotropic index (7# rotor, η 10rpm / η 1rpm ) of this thermal conductive silicone grease is 16.4; the thermal resistance (40 psi) is 0.019 cm 2 .K / W. After high-temperature aging at 150 °C for 1000 hours, the change rate of the thermal resistance (40 psi) is 2.1%. After high-temperature aging at 150 °C for 5000 hours, the change rate of the thermal resistance (40 psi) is less than 3.3%. Comparative Example 1

[0072] Use the commercially available Dow TC5888 thermal conductive silicone grease.

[0073] After testing, at 25 °C, the thixotropic index (7# rotor, η 10rpm / η 1rpm ) of this thermal conductive silicone grease is 8.9; the thermal resistance (40 psi) is 0.044 cm 2 .K / W. After high-temperature aging at 150 °C for 1000 hours, the change rate of the thermal resistance (40 psi) is 5.2%. After high-temperature aging at 150 °C for 5000 hours, the change rate of the thermal resistance (40 psi) is 6.7%. Comparative Example 2

[0074] Use the commercially available Shin-Etsu 7921 thermal conductive silicone grease.

[0075] After testing, at 25 °C, the thixotropic index (7# rotor, η 10rpm / η 1rpm ) of this thermal conductive silicone grease is 7.7; the thermal resistance (40 psi) is 0.042 cm 2 .K / W. After high-temperature aging at 150 °C for 1000 hours, the change rate of the thermal resistance (40 psi) is 6.1%. After high-temperature aging at 150 °C for 5000 hours, the change rate of the thermal resistance (40 psi) is 8.9%. Comparative Example 3

[0076] The difference between this comparative example and Example 1 is that the micron-sized AlCe microspheres are replaced with micron-sized Al microspheres, and the Ce element is not added to the Al matrix.

[0077] The preparation method is the same as that of Example 1. After testing, at 25 °C, the thixotropic index (7# rotor, η 10rpm / η 1rpm ) of this thermal grease is 11.1; the thermal resistance (40 psi) is 0.041 cm 2 .K / W; the change rate of the thermal resistance (40 psi) after 1000 hours of high-temperature aging at 150 °C is 4.7%, and the change rate of the thermal resistance (40 psi) after 5000 hours of high-temperature aging at 150 °C is 7.7%.

[0078] The present invention provides an idea and method for a high-thixotropic, low-thermal-resistance, and ultra-long-life thermal grease and its preparation method. There are many specific methods and ways to implement this technical solution. The above description is only the preferred embodiment of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention. Each component not clearly defined in this embodiment can be implemented by the prior art.

Claims

1. A highly thixotropic, low thermal resistance, ultra-long life thermal conductive silicone grease, characterized in that It comprises the following components by weight percentage: Micron-sized AlCe microspheres: 65 - 87 wt%; AlN nano-microspheres: 6 - 26 wt%; Acrylonitrile-butadiene-styrene nano-plastic microspheres: 2 - 4 wt%; Vinyl-terminated silicone oil: 2 - 2.5 wt%; Methyl-terminated silicone oil: 0.5 - 0.75 wt%; Hydroxyl-terminated silicone oil: 0.5 - 0.75 wt%; Polyglycerol-10 laurate: 1 - 2 wt%; The branching factor of the vinyl-terminated silicone oil is 0.3 - 0.5; The branching factor of the methyl-terminated silicone oil is 0.7 - 0.9; The branching factor of the hydroxyl-terminated silicone oil is 0.4 - 0.

6.

2. The high thixotropic, low thermal resistance and ultra-long life thermal conductive silicone grease according to claim 1, characterized in that, In the micron-sized AlCe microspheres, the mass ratio of Ce element to Al element is 0.02 - 0.

025.

3. The high thixotropic, low thermal resistance, ultra-long life thermal conductive silicone grease according to claim 1, characterized in that The micron-sized AlCe microspheres include AlCe microspheres with a particle size of 4 - 6 microns, AlCe microspheres with a particle size of 1 - 3 microns, and AlCe microspheres with a particle size of 0.3 - 0.5 microns.

4. The highly thixotropic, low thermal resistance, ultra-long life thermal conductive silicone grease according to claim 3, characterized in that, The mass percentage of the AlCe microspheres with a particle size of 4 - 6 microns is 40 wt% - 50 wt%, the mass percentage of the AlCe microspheres with a particle size of 1 - 3 microns is 20 wt% - 30 wt%, and the mass percentage of the AlCe microspheres with a particle size of 0.3 - 0.5 microns is 5 wt% - 7 wt%.

5. The thixotropic thermal grease with high thixotropy, low thermal resistance and ultra-long service life according to claim 1, characterized in that The particle size of the AlN nano-microspheres is 100 - 300 nanometers.

6. The high thixotropic, low thermal resistance and ultra-long life thermal conductive silicone grease according to claim 1, characterized in that, The particle size of the acrylonitrile-butadiene-styrene nano-plastic microspheres is 50 - 100 nanometers.

7. The thixotropic thermal conductive silicone grease with high thixotropy, low thermal resistance and ultra-long service life according to claim 1, wherein The kinematic viscosity of the vinyl-terminated silicone oil is 150 cst.

8. The high thixotropic, low thermal resistance and ultra-long life thermal conductive silicone grease according to claim 1, wherein The kinematic viscosity of the methyl-terminated silicone oil is 100 cst.

9. The high thixotropic, low thermal resistance and ultra-long life thermal conductive silicone grease according to claim 1, wherein The kinematic viscosity of the hydroxyl-terminated silicone oil is 300 cst.

10. The preparation method of the highly thixotropic, low thermal resistance and ultra-long life thermal conductive silicone grease according to claim 1, characterized in that, It comprises the following steps: (1) Mix the vinyl-terminated silicone oil and the methyl-terminated silicone oil, stir at a speed of 300 - 500 rpm, and continuously stir for 10 - 30 minutes to obtain a first mixture; (2) Mix the hydroxyl-terminated silicone oil and the polyglycerol-10 laurate, stir at a speed of 300 - 500 rpm, and continuously stir for 10 - 30 minutes to obtain a second mixture; (3) Add the acrylonitrile-butadiene-styrene plastic microspheres to the second mixture obtained in step (2), heat up to 60 - 80 °C, stir at 300 - 500 rpm, and continuously stir for 1 - 3 hours. After cooling to room temperature, obtain a first mixture; (4) Add the first mixture obtained in step (1) to the first mixture obtained in step (3), stir at a speed of 300 - 500 revolutions per minute for 20 - 40 minutes to obtain a second mixture; (5) Add the micron-sized AlCe microspheres and the AlN nano-microspheres to cyclohexane in proportion, seal and stir for 1 - 3 hours, stir at a speed of 100 - 300 rpm to obtain a third mixture; where the mass sum of the microspheres and the mass ratio of cyclohexane is 3 - 4:1; (6) Add the second mixture to the third mixture obtained in step (5) in proportion, seal and stir, stir at a speed of 700 - 900 rpm, and stir for 5 - 15 minutes to obtain a fourth mixture; (7) opening the lid of the container containing the fourth mixture, removing the sealing state, raising the temperature to 40-50° C., evacuating the pressure to below 2 kPa, and maintaining the pressure for 2-4 hours to remove the cyclohexane, and cooling to room temperature to obtain a fifth mixture; (8) The fifth mixture obtained in step (7) is subjected to vacuum degassing at room temperature with a stirring speed of 1000-1200 rpm, a vacuum degree of less than 1 kPa, and a degassing time of 10-20 minutes to obtain the fifth mixture.

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