Vapor chamber based on high thermal conductivity aerogel / micro-groove composite capillary wick and preparation method

Abstract

The present application relates to a heat spreading plate based on high-thermal-conductivity aerogel / micro-groove composite capillary wick and a preparation method thereof, the heat spreading plate comprising an evaporation lower plate and a condensation upper plate, the evaporation lower plate and the condensation upper plate being sealingly connected, the evaporation lower plate having a hollow cavity inside, the evaporation lower plate having a liquid injection port communicated with the hollow cavity, and further comprising four lateral converging micro-groove structures, the four lateral converging micro-groove structures being uniformly arranged on the top surface of the evaporation lower plate and each being communicated with the hollow cavity, each two adjacent lateral converging micro-groove structures having a gap therebetween, the two adjacent lateral converging micro-groove structures being symmetrical along the gap, and the four gaps being communicated with the center of the evaporation lower plate; an MXene-graphene aerogel capillary wick plate being located on the evaporation lower plate and being integrally formed with the evaporation lower plate. The present application also provides a preparation method of the heat spreading plate. The present application improves the temperature uniformity and liquid return capacity of the heat spreading plate.

Description

Technical Field

[0001] This invention belongs to the field of heat dissipation and cooling technology for high power density microelectronic power devices, and specifically relates to a heat spreader based on a high thermal conductivity aerogel / microgroove composite capillary core and its preparation method. Background Technology

[0002] With the advancement of microprocessor (CPU, GPU) manufacturing technology, the increase in core count, and the emergence of new application scenarios such as AI and deep learning, the power and energy consumption of microprocessors are gradually increasing, along with their operating temperatures. Therefore, corresponding thermal management technologies urgently need development. Heat sinks, which operate using the latent heat of vaporization of the working fluid, are particularly suitable for dissipating heat from small-area, high-power-density heat sources. Passive heat sinks combined with active cooling methods, such as air-cooled fins or liquid-cooled water cooling plates, can evenly transfer the heat from a small area of ​​the microprocessor to the condensation end of a large-area heat sink through the rapid longitudinal and lateral movement of vapor in a vacuum environment. This efficiently removes heat from the microprocessor while avoiding the formation of localized hot spots, facilitating long-term high-power operation of the microprocessor.

[0003] The core of a vapor chamber lies in its working fluid, which possesses high surface tension and high latent heat of vaporization, filling the environment into a near-vacuum. Equally important is the capillary structure within the vapor chamber; a well-designed capillary wick should consider both heat diffusion and working fluid transport. Regarding heat diffusion, the capillary wick design ensures uniform heat diffusion from the heat source to the entire vapor chamber, while maintaining an optimal liquid film meniscus within the vapor chamber for efficient evaporation and capillary pressure. Regarding working fluid transport, the capillary wick design should facilitate the rapid return of the condensed working fluid to the heat source center. Currently, most commercially available vapor chambers and their capillary wicks are made of copper, such as copper mesh, copper foam, and copper microgrooves. These three types of capillary structures often have significant room for improvement in heat diffusion and working fluid transport, particularly in terms of liquid return capability. Therefore, developing a vapor chamber based on a high thermal conductivity aerogel / microgroove composite capillary wick and its preparation method to improve temperature uniformity and liquid return capability is of great significance. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a heat spreader based on a high thermal conductivity aerogel / microgroove composite capillary core and its preparation method, which improves the temperature uniformity and liquid return capability of the heat spreader.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a heat spreader based on a high thermal conductivity aerogel / microgroove composite capillary core, comprising a lower evaporation plate and an upper condensation plate, wherein the lower evaporation plate and the upper condensation plate are sealed together, the lower evaporation plate has a hollow cavity inside, and a liquid injection port communicating with the hollow cavity is opened on the side wall of the lower evaporation plate, further comprising:

[0006] The lateral converging microgroove structure is configured as four, and the four lateral converging microgroove structures are evenly distributed on the top surface of the lower evaporation plate and are all connected to the hollow cavity. There is a gap between every two adjacent lateral converging microgroove structures, and every two adjacent lateral converging microgroove structures are symmetrical along the gap. All four gaps are connected to the center of the lower evaporation plate.

[0007] An MXene-graphene aerogel capillary core plate is located on an evaporation plate, and the MXene-graphene aerogel capillary core plate has four MXene-graphene aerogel capillary cores adapted to four laterally converging microgroove structures.

[0008] Four lateral converging microgrooves are used to diffuse heat laterally, and four MXene-graphene aerogel capillaries are used to diffuse heat longitudinally. The combination of the four MXene-graphene aerogel capillaries and the four lateral converging microgrooves is also used to direct the flow of the working fluid.

[0009] Preferably, the four gaps coincide with the cross-shaped center line of the lower evaporation plate, and each lateral converging microgroove structure includes multiple parallel microgrooves arranged at equal intervals, with each microgroove having a width of 1.5 mm and a height of 1 mm.

[0010] Preferably, each microgroove forms a 45° angle with the centerline of the lower evaporation plate.

[0011] Preferably, the MXene-graphene aerogel capillary core plate is integrally formed with the evaporation lower plate by multiple support columns, and the multiple support columns are arranged vertically on each gap. The MXene-graphene aerogel capillary core plate (2) also has multiple grooves that are adapted to the multiple support columns. The multiple support columns are used to make the MXene-graphene aerogel capillary core form mechanical support along the height direction.

[0012] Preferably, multiple support columns 1.2 are evenly distributed in each gap, the distance between two adjacent support columns is 8.5mm, the length of each support column is 1.5mm to 1.8mm, the width of each support column is 1.5mm to 1.8mm, the height of each support column is 2mm, and the thickness of the MXene-graphene aerogel capillary core plate is 0.08mm.

[0013] Preferably, a welding rod groove is provided at the edge of the top wall of the lower evaporator plate, and the upper condenser plate and the lower evaporator plate are welded together by welding rods in the welding rod groove.

[0014] Preferably, both the lower evaporator plate and the upper condenser plate are aluminum-based rectangular plates, and the four lateral converging microgrooves are symmetrically arranged in pairs, with the gap between each pair of lateral converging microgrooves coinciding with the cross-shaped center line of the lower evaporator plate.

[0015] This invention provides a method for preparing a heat spreader based on a high thermal conductivity aerogel / microgroove composite capillary core, comprising the following steps:

[0016] Four lateral converging microgrooves are fabricated on the top surface of the lower evaporator plate;

[0017] An MXene-graphene aerogel capillary core plate is integrally formed on an evaporation lower plate with four lateral converging microgrooves.

[0018] Then, the upper condenser plate and the lower evaporator plate are sealed together to obtain a heat spreader plate;

[0019] The processing steps for the MXene-graphene aerogel capillary core plate integrally formed by evaporation are as follows:

[0020] The prepared MXene-graphene solution was poured into an evaporation plate with four lateral converging microgrooves and freeze-dried to obtain MXene-graphene aerogel with a thermal conductivity of 25 W / m·K to 30 W / m·K. Then, the evaporation plate with MXene-graphene aerogel was integrally molded and calcined at high temperature.

[0021] Preferably, a titanium layer with a thickness of 40mm to 50mm is sputtered onto the four lateral converging microgroove structures, and the condensation upper plate is covered by the evaporation lower plate with MXene-graphene aerogel for integral molding, high-temperature calcination and sealing connection.

[0022] Preferably, the freeze-drying temperature is -60℃, the freeze-drying time is 12h, and the high-temperature calcination is divided into three stages: the first stage calcination is to raise the temperature from 25℃ to 80℃ at a heating rate of 2℃ / min and hold for 0.5h; the second stage calcination is to raise the temperature from 80℃ to 150℃ at a heating rate of 1℃ / min and hold for 1.0h; the third stage is to raise the temperature from 150℃ to 300℃ at a heating rate of 0.5℃ / min and hold for 2h.

[0023] Preferably, the MXene-graphene solution is prepared by the following method: 50 mg of multilayer accordion-shaped MXene is added to 10 ml of graphene oxide aqueous solution with a concentration of 10 mg / ml, mixed and ultrasonicated for 10 min, then 50 mg of L-cysteine ​​and 100 mg of L-ascorbic acid are added, and the mixture is stirred in an ice bath under a helium atmosphere for 30 min, and ultrasonicated for 10 min to obtain the MXene-graphene solution.

[0024] This invention provides an application of a heat spreader based on MXene-graphene aerogel / microgroove composite capillary core in aerospace heat dissipation.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] This invention designs a heat spreader based on a high thermal conductivity aerogel / microgroove composite capillary core, which solves the problems of poor temperature uniformity and liquid return capacity of the original copper heat spreader.

[0027] This is because the lower evaporator plate is machined to form four lateral converging microgrooves. These four microgrooves, with their high permeability, can quickly guide the condensed working fluid to the heat source, maintaining an uninterrupted liquid film at the heat source, preventing it from drying out, and improving the liquid return capability to cool the microprocessor. Simultaneously, due to their unique design, the lateral converging microgrooves allow visible heat to diffuse laterally from the central heat source throughout the lower evaporator plate, reducing the diffusion thermal resistance of the heat spreader. The MXene-graphene aerogel capillary core in the MXene-graphene aerogel capillary core plate has a certain thermal conductivity, especially at the vertical heat source, facilitating the directional transfer of heat to the evaporator liquid film interface for longitudinal diffusion (specifically, the MXene-graphene aerogel capillary core is combined with the lower evaporator plate through a titanium-plated layer, making the contact thermal resistance negligible), reducing the evaporation thermal resistance of the heat spreader and improving the liquid return capability.

[0028] The MXene-graphene aerogel capillary core in the MXene-graphene aerogel capillary core plate possesses extremely high capillary pressure due to the unique two-dimensional layered structure and high electron and phonon mobility of MXene and graphene, the honeycomb structure obtained through directional freeze-drying technology, the repair of lattice defects between MXene and graphene induced by high-temperature calcination during preparation, the inherent micron-sized pores and porosity (over 98%) of the aerogel, and the hydrophilic properties of MXene. Therefore, the combination of the MXene-graphene aerogel capillary core and the lateral converging microgroove structure, along with the directional heat transfer channels and the combination of high permeability and high capillary pressure, can reduce the overall thermal resistance of the heat spreader and improve its temperature uniformity.

[0029] Compared to traditional metal capillary cores (such as sintered copper), the MXene-graphene aerogel capillary core plate of this invention has an extremely low density (approximately 15,000 g / m³). 3 This significantly reduces the weight of the vapor chamber, providing effective technical support for lightweight design. By adopting this MXene-graphene aerogel capillary core plate, the vapor chamber not only improves heat transfer efficiency but also achieves more uniform temperature distribution and faster working fluid circulation, making it particularly suitable for heat dissipation applications with high heat flux density and lightweight requirements.

[0030] The evaporator lower plate and condenser upper plate provided in this invention are both aluminum-based rectangular plates. By introducing MXene-graphene aerogel into the evaporator lower plate and condenser upper plate, the problem of aluminum being easily oxidized and unable to form capillary structures by sintering aluminum foam is overcome. A porous structure is realized on the aluminum heat spreader plate. The porous MXene-graphene aerogel, combined with the lateral converging microgroove structure, realizes directional and rapid liquid return, thereby achieving temperature uniformity under high heat flux density. At the same time, the titanium plating layer also solves the problem of easy corrosion of aluminum-based heat spreader plates.

[0031] Finally, compared to traditional metal capillary cores (such as sintered copper), aerogel capillary cores have an extremely low density (approximately 15,000 g / m³). 3 This significantly reduces the weight of the vapor chamber. Furthermore, both the lower evaporator plate and the upper condenser plate are made of aluminum, further reducing weight and providing effective technical support for lightweight design. By employing this composite aerogel capillary core structure, the vapor chamber not only improves heat transfer efficiency but also achieves a more uniform temperature distribution and faster working fluid circulation, making it particularly suitable for heat dissipation applications with high heat flux density and lightweight requirements. Attached Figure Description

[0032] Figure 1-1 This is a schematic cross-sectional view of the three-dimensional structure of the present invention.

[0033] Figure 1-2 This is an exploded three-dimensional structural view of the present invention.

[0034] Figure 2-1 This is a three-dimensional view of the lower evaporation plate of the present invention.

[0035] Figure 2-2 This is a front view of the lower evaporation plate of the present invention.

[0036] Figure 2-3 This is a top view of the lower evaporation plate of the present invention.

[0037] Figure 2-4 This is a cross-sectional view of the lower evaporation plate of the present invention.

[0038] Figure 3-1 This is a three-dimensional diagram of the MXene-graphene aerogel capillary core of the present invention.

[0039] Figure 3-2 This is a front view of the MXene-graphene aerogel capillary core of the present invention.

[0040] Figure 4-1 This is a three-dimensional view of the condenser plate of the present invention.

[0041] Figure 4-2 This is a front view of the condenser plate of the present invention.

[0042] Figure 4-3 This is a top view of the condenser plate of the present invention.

[0043] Figure Labels

[0044] 1. Evaporation lower plate; 1.1. Titanium plating layer; 1.2. Support column; 1.3. Welding rod groove; 1.4. Lateral converging microgroove structure; 1.5. Liquid injection port; 2. MXene-graphene aerogel capillary core; 3. Condensation upper plate. Detailed Implementation

[0045] The specific embodiments of the present invention are described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention. Unless otherwise specified, the experimental methods described in the embodiments of the present invention are conventional methods.

[0046] The inventors discovered that in current aluminum-based vapor chamber fabrication, due to the easy oxidation of aluminum, microgrooves are often formed through machining. Therefore, aluminum-based vapor chambers often exhibit poor temperature uniformity under high heat flux densities due to a lack of capillary pressure. On the other hand, porous Mxene-graphene composite aerogels, with their customizable porous structures, possess good thermal conductivity. This means that the aerogel can provide good capillary pressure and rapid heat transfer channels, and currently, Mxene-graphene composite aerogels have not been used in vapor chambers.

[0047] In view of this, the present invention provides a vapor chamber based on a high thermal conductivity aerogel / microgroove composite capillary core and its preparation method to overcome the problems existing in the prior art. In the present invention, the inherent high longitudinal thermal conductivity of MXene-graphene aerogel allows heat to be rapidly and vertically conducted from the heat source to the liquid film interface, maintaining the optimal radius of curvature of the liquid film interface, which is beneficial for liquid film evaporation and maintaining maximum capillary pressure. The machined aluminum-based lateral converging microgrooves, due to their distribution and the high thermal conductivity of aluminum, allow heat to spread rapidly laterally from the heat source, ensuring uniform heating of the entire liquid film and avoiding local hot spots. The combination of these two factors reduces the evaporation thermal resistance and diffusion thermal resistance of the vapor chamber, which is beneficial for its temperature uniformity. In particular, in the present invention, a nanoscale titanium coating layer exists between the MXene-graphene aerogel and each lateral converging microgroove structure, which reduces the contact thermal resistance between the aerogel and each lateral converging microgroove structure through chemical bonding. Secondly, the high thermal conductivity aerogel / microgroove composite capillary core of this invention combines the high capillary pressure brought by the high porosity and hydrophilicity of the aerogel with the high permeability brought by the millimeter-scale microgrooves, enabling the working fluid within the heat spreader to be smoothly and unimpededly transported to the heat source center during operation, completing an efficient circulation. Furthermore, the lightweight nature of the aerogel and aluminum gives the overall heat spreader an extremely light weight, facilitating its use in specific applications.

[0048] As attached Figure 1-1 ~Attached Figure 4-3 As shown, this invention provides a heat spreader based on a high thermal conductivity aerogel / microgroove composite capillary core, including a lower evaporation plate 1 and an upper condensation plate 3, which are sealed together. The lower evaporation plate 1 has a hollow cavity inside, and a liquid injection port 1.5 communicating with the hollow cavity is opened on the side wall of the lower evaporation plate 1. It also includes: a lateral converging microgroove structure 1.4 and an MXene-graphene aerogel capillary core plate 2, wherein...

[0049] Four lateral converging microgroove structures 1.4 are set up, and the four lateral converging microgroove structures 1.4 are evenly distributed on the top surface of the lower evaporation plate 1 and are all connected to the hollow cavity. There is a gap between every two adjacent lateral converging microgroove structures 1.4, and every two adjacent lateral converging microgroove structures 1.4 are symmetrical along the gap. All four gaps are connected to the center of the lower evaporation plate 1.

[0050] The MXene-graphene aerogel capillary core plate 2 is located on the lower evaporation plate 1, and the MXene-graphene aerogel capillary core plate 2 has four MXene-graphene aerogel capillary cores adapted to the four laterally converging microgroove structures 1.4.

[0051] This invention proposes a heat spreader based on the principles of high thermal conductivity MXene and graphene structures, directional freezing to control ice crystal growth to form a vertically thermally conductive honeycomb structure, lateral convergence processing of a longitudinally thermally conductive network, high capillary pressure of aerogel on the working fluid, and high permeability of aluminum-based microgrooves. After the lower evaporator plate 1 receives heat from the heat source, the heat is directionally transferred along the lateral convergence microgrooves 1.4 and the MXene-graphene aerogel. This heat transfer design allows the liquid film (deionized water) formed in the MXene-graphene aerogel capillary core plate 2 to be uniformly heated while maintaining an optimal meniscus.

[0052] When a small-volume heat source with high heat flux density is combined with the lower evaporator plate 1 at the bottom of the heat spreader, the heat from the center of the lower evaporator plate 1 to the heat source will dissipate in two directions. One dissipation direction is: the lateral converging microgroove structure 1.4 evenly dissipates the heat from the center of the lower evaporator plate 1 to the surrounding area; the other dissipation direction is: the MXene-graphene aerogel in the MXene-graphene aerogel capillary core plate 2 transfers the heat from the lower evaporator plate 1, through the titanium-plated layer 1.1, vertically to the working fluid (water) liquid film interface. The lateral heat diffusion ensures uniform heat transfer between the entire lower evaporator plate 1 and the working fluid liquid film, avoiding the formation of local hot spots in the center due to insufficient liquid replenishment capacity at high power densities; the longitudinal heat diffusion ensures that the center of the liquid film meniscus corresponding to the heat source always maintains a certain curvature, thus maintaining efficient liquid film evaporation and capillary liquid absorption capacity; the combination of these two factors allows the working fluid to evaporate rapidly and evenly and move to the condenser plate 3. In addition, the MXene-graphene aerogel in the MXene-graphene aerogel capillary core plate 2 has high porosity. The high porosity, combined with the high permeability of the lateral converging microgroove structure 1.4, can directionally transport the liquid working fluid condensed by the self-condensing upper plate 3 back to the heat source center to complete the next working fluid heat transfer cycle.

[0053] The high thermal conductivity of the MXene-graphene aerogel capillary core in the MXene-graphene aerogel capillary core plate 2 is due to the following four points: (1) MXene, one of the constituent materials, has a highly ordered and small-spaced layered structure, resulting in a short heat conduction path. The strong metallic bonds between titanium and carbon atoms in MXene also contribute to heat conduction. (2) Graphene, one of the constituent materials, has a sheet-like structure with extremely strong free electron migration ability, and the sp bonds between carbon atoms are also very strong. 2The hybrid bonds are extremely strong and can effectively transfer heat; the aerogel formed after the two are directionally freeze-dried forms a highly compact vertical honeycomb network structure, which can transfer heat longitudinally; after the aerogel is calcined at 300℃, the defects of MXene and graphene are reduced, the crystal structure is optimized, and its internal heat conduction path is improved. (3) There is a titanium coating between the composite aerogel and the aluminum-based microgroove. After calcination at 300℃, the titanium coating can bond with the carbon in MXene and graphene (mainly the activated carbon atoms in MXene) to generate Ti-C bonds. The tight bonding and the high bonding area brought by the microgroove reduce the contact thermal resistance between the evaporation plate and the capillary wick. The high thermal conductivity of the aerogel and the tight bonding between the aerogel and the evaporation plate make it possible for the evaporation plate with aluminum-based microgroove to quickly transfer heat to the surroundings after receiving heat from the heat source when the aerogel is used as a capillary wick (the aerogel transfers heat efficiently longitudinally, and the aluminum-based microgroove transfers heat efficiently laterally), which greatly reduces the overall thermal resistance of the heat spreader and improves the temperature uniformity. The inherent high porosity and uniformly distributed pore structure of MXene-graphene aerogel enable the capillary wick to have high capillary pressure. Combined with the high permeability of the lateral converging microgrooves of the evaporation plate, the condensing working fluid can be directionally transferred to the heat source area, avoiding flow dead zones and ensuring the efficient operation of the heat spreader. (4) The hydrophilic groups on MXene facilitate the wetting of the working fluid and also contribute to the high capillary pressure of the capillary wick. On the other hand, the aerogel has a unique low density (low density is 15000 g / m³). 3 The combination of aluminum and other materials results in a lightweight vapor chamber, which is advantageous for specific applications such as aerospace. The upper condenser plate and the lower evaporator plate are both made of aluminum alloy.

[0054] Specifically, such as Figure 1-2 and Figure 2-1 As shown, the four gaps coincide with the cross-shaped center line of the lower evaporator plate 1.

[0055] Specifically, each lateral converging microgroove structure 1.4 includes multiple parallel and equally spaced microgrooves, with both ends of each microgroove connected to the gaps on both sides. Each microgroove has a width of 1.5 mm and a height of 1 mm. The width of the microgroove is determined by the viscosity of the aerogel precursor solution; if the microgroove is too narrow, the aerogel solution cannot flow, and if the microgroove is too wide, there is no capillary force, and it cannot absorb water.

[0056] Specifically, each micro-groove forms a 45° angle with the center line of the lower evaporator plate 1. The reason for setting it at 45° is to form micro-grooves that converge laterally around the perimeter, guiding the heat source. Otherwise, under high heat flux density, the heat source would dry out due to the lack of working fluid return, forming a hot spot.

[0057] Specifically, the MXene-graphene aerogel capillary core plate 2 is integrally formed with the evaporation lower plate 1 by multiple support columns 1.2. The multiple support columns 1.2 are arranged vertically in each gap. The MXene-graphene aerogel capillary core plate 2 also has grooves adapted to the multiple support columns 1.2. The multiple support columns 1.2 are used to form mechanical support for the MXene-graphene aerogel capillary core 2 along the height direction.

[0058] Multiple support columns 1.2 and multiple grooves ensure that the heat exchange plate will not deform due to internal and / or external pressure during operation. The injection port 1.5 is connected to an injection pipe, the length of which is arbitrary and can be selected as 20mm. The injection pipe is first evacuated before conveying the working fluid.

[0059] Specifically, multiple support columns 1.2 are evenly distributed in each gap, with a spacing of 8.5 mm between two adjacent support columns 1.2. The length of each support column 1.2 is 1.5 mm to 1.8 mm, the width of each support column 1.2 is 1.5 mm to 1.8 mm, and the height of each support column 1.2 is 2 mm. The height of the MXene-graphene aerogel capillary core plate 2 is 0.08 mm.

[0060] If the height of the MXene-graphene aerogel capillary core plate 2 is too low, the overall liquid storage capacity will be small, and local drying will occur under high heat flux density, which is not conducive to temperature uniformity. If the height of the MXene-graphene aerogel capillary core plate 2 is too high, the overall heat spreader will be too thick, and it will be difficult to excite under low flux density, resulting in excessively high thermal resistance. The thickness of the MXene-graphene aerogel capillary core plate 2 is 0.08 mm, which is just right to match the lateral converging microgroove structure 1.4.

[0061] The length, width, and height of each support column 1.2 are limited here after taking into account the steam pressure drop, in order to reduce the flow resistance between the steam and the main body. The length is fixed so that it can fit tightly against the aluminum plates of the lower evaporator plate 1 and the upper condenser plate 3.

[0062] Specifically, a welding rod groove 1.3 is provided at the top edge of the evaporation lower plate 1. The condensation upper plate 3 and the evaporation lower plate 1 are welded together by welding rods in the welding rod groove 1.3 so that the MXene-graphene aerogel capillary core 2 and the evaporation lower plate 1 form mechanical support along the height direction, which can ensure that the heat spreader will not deform due to internal and / or external pressure during operation.

[0063] Both the lower evaporator plate 1 and the upper condenser plate 3 are aluminum-based rectangular plates. The dimensions of the lower evaporator plate 1 are l1×l2×h1, with a length of l1=78mm, a width of l2=78mm, and an overall height of h1=2.5mm. An internal cavity is machined within the lower evaporator plate to support the microgrooves and support columns. This cavity has dimensions l3×l4×h2, with a length of l3=70mm, a width of l4=70mm, and an overall height of h2=2mm. A 50nm thick titanium layer is deposited on the lower evaporator plate by magnetron sputtering. The lower evaporator plate contains 12 support columns arranged in a cross shape. Each support column has dimensions w1×w2×h3, with a length of w1=1.5mm, a width of w2=1.5mm, and an overall height of h3=2mm. The spacing between each support column is w3=8.5mm. The lower evaporator plate has welding rod grooves machined around its perimeter. The dimensions of these grooves are l5×l6×l7×l8×w4×h4. The outer frame length is l5=76mm, the outer frame width is l6=76mm, the inner frame length is l7=72mm, the inner frame width is l8=72mm, the overall width is w4=2mm, and the overall height is h4=0.15mm. Inside the lower evaporator plate are micro-grooves arranged in a laterally converging pattern. The dimensions of these micro-grooves are w5×r1×h5, the width is w5=1.5mm, the angle along the horizontal (vertical) central axis is r1=45°, and the overall height is h5=1mm. The dimensions of the liquid injection port are d1×d2×h6, the outer diameter is d1=2mm, the inner diameter is d2=1.5mm, and the overall height is h6=20mm. The dimensions of the upper condenser plate are l9×l 10 ×h8, length l9=78mm, width l 10 =78mm, and the overall height is h8=0.5.

[0064] The dimensions provided here are to control the overall thickness of the aluminum-based heat spreader within a certain range. The heat spreader should not be too thick, which reduces weight and improves practicality. This is because if it is too thick, it will not fit into compact power devices with high heat flux density.

[0065] Both the lower evaporator plate 1 and the upper condenser plate 3 are aluminum-based rectangular plates. The four lateral converging microgrooves 1.4 are symmetrically arranged in pairs, and the gap between each pair of lateral converging microgrooves 1.4 coincides with the cross-shaped center line of the lower evaporator plate 1.

[0066] By introducing MXene-graphene aerogel onto the lower evaporator plate 1 and the upper condenser plate 3, the problem of aluminum being easily oxidized and unable to form capillary structures by sintering aluminum foam on aluminum plates is overcome. A porous structure is realized on the aluminum heat exchanger plate. The porous MXene-graphene aerogel, combined with the lateral convergent microgroove structure, realizes directional and rapid liquid return, thereby achieving temperature uniformity under high heat flux density. At the same time, the titanium plating layer also solves the problem of easy corrosion of aluminum-based heat exchangers.

[0067] A heat spreader based on a high thermal conductivity aerogel / microgroove composite capillary core and its preparation method, comprising the following steps:

[0068] Four lateral converging microgroove structures 1.4 are machined on the top surface of the lower evaporator plate 1;

[0069] An MXene-graphene aerogel capillary core plate 2 is integrally formed on an evaporation lower plate 1 with four lateral converging microgroove structures 1.4.

[0070] Then, the upper condenser plate 3 and the lower evaporator plate 1 are sealed together to obtain a heat spreader plate;

[0071] The processing steps for the integrally molded MXene-graphene aerogel capillary core plate 2 of the evaporation lower plate 1 are as follows:

[0072] The prepared MXene-graphene solution was poured onto the lower evaporation plate 1, which has four laterally converging microgrooves 1.4, and freeze-dried to obtain MXene-graphene aerogel with a thermal conductivity of 28 W / m·K. Then, the lower evaporation plate 1 with MXene-graphene aerogel was integrally molded and calcined at high temperature.

[0073] The processing steps for the integrally molded MXene-graphene aerogel capillary core plate 2 of the evaporation lower plate 1 are as follows:

[0074] The prepared MXene-graphene solution was poured onto the lower evaporation plate 1, which has four laterally converging microgrooves 1.4, and freeze-dried to obtain MXene-graphene aerogel with a thermal conductivity of 25 W / m·K. Then, the lower evaporation plate 1 with MXene-graphene aerogel was integrally molded and calcined at high temperature.

[0075] The processing steps for the integrally molded MXene-graphene aerogel capillary core plate 2 of the evaporation lower plate 1 are as follows:

[0076] The prepared MXene-graphene solution was poured onto the lower evaporation plate 1, which has four laterally converging microgrooves 1.4, and freeze-dried to obtain MXene-graphene aerogel with a thermal conductivity of 30 W / m·K. Then, the lower evaporation plate 1 with MXene-graphene aerogel was integrally molded and calcined at high temperature.

[0077] Specifically, a titanium layer with a thickness of 40mm to 50mm is sputtered onto four lateral converging microgroove structures 1.4. The condensation upper plate 3 is covered by the evaporation lower plate 1 with MXene-graphene aerogel and is integrally formed, calcined at high temperature and sealed. The titanium layer with a thickness of 40mm to 50mm mainly solves the problem of easy corrosion of aluminum-based heat spreaders.

[0078] Specifically, the freeze-drying temperature is -60℃, the freeze-drying time is 12h, and the high-temperature calcination is divided into three stages: the first stage calcination is to raise the temperature from 25℃ to 80℃ at a heating rate of 2℃ / min and hold for 0.5h; the second stage calcination is to raise the temperature from 80℃ to 150℃ at a heating rate of 1℃ / min and hold for 1.0h; and the third stage is to raise the temperature from 150℃ to 300℃ at a heating rate of 0.5℃ / min and hold for 2h.

[0079] The control of calcination time and rate is to protect the mechanical properties of the aerogel, ensuring it has a certain degree of elasticity. Secondly, it allows the MXene-graphene within the aerogel to complete lattice repair, improving thermal conductivity and thus reducing the overall thermal resistance of the vapor chamber and improving temperature uniformity. The duration and rate of freeze-drying are not significant; the important aspect is the directional freezing to form a vertical honeycomb structure, enabling directional heat separation and improving the temperature uniformity of the vapor chamber.

[0080] Specifically, the MXene-graphene solution is prepared by the following method: 50 mg of multilayer accordion-shaped MXene is added to 10 ml of graphene oxide solution with a concentration of 10 mg / ml, and the mixture is sonicated for 10 min. Then, 50 mg of L-cysteine ​​and 100 mg of L-ascorbic acid are added, and the mixture is stirred in an ice bath under a helium atmosphere for 30 min. After sonication for 10 min, the MXene-graphene solution is obtained.

[0081] Application of a vapor chamber based on MXene-graphene aerogel / microgroove composite capillary core in aerospace heat dissipation.

[0082] This invention discloses a heat spreader based on a high thermal conductivity aerogel / microgroove composite capillary core, mainly comprising a lower evaporation plate 1, an MXene-graphene aerogel capillary core plate 2, and a condenser upper plate 3. It is manufactured using precision machining, magnetron sputtering coating technology, directional freeze-drying technology, brazing technology, and cold welding technology.

[0083] The evaporation lower plate 1 is fabricated with support columns 1.2, welding rod grooves 1.3, lateral converging microgroove structures 1.4, and injection pipes 1.5. A titanium layer 1.1 is then applied to the evaporation lower plate 1 using a magnetron sputtering coating machine. MXene-graphene aerogel is fabricated using a multi-layer accordion-shaped MXene and graphene oxide (GO) solution through directional freeze-drying technology. The evaporation lower plate 1, MXene-graphene aerogel, and condensation upper plate are then integrated using brazing technology to create an MXene-graphene aerogel capillary core plate 2. A VC vacuum injection system is connected to the injection pipe 1.5 for vacuum treatment and injection. The injection port 1.5 is then sealed using cold welding technology, thus completing the fabrication of an aluminum-based heat spreader based on the MXene-graphene aerogel / microgroove composite directional heat-conducting capillary core. The purpose of sealing the injection port 1.5 using cold welding is to prevent the overall temperature of the aluminum-based heat spreader from becoming too high and causing irreversible deformation.

[0084] Working principle:

[0085] Throughout the operation, the heat source transfers heat to the lower evaporator plate 1. On one hand, the MXene-graphene aerogel on the lower evaporator plate 1, with its vertical honeycomb structure, can directionally and rapidly transfer heat to the meniscus of the liquid film through the titanium plating layer, maintaining the optimal curvature of the meniscus and promoting rapid evaporation and return of the working fluid. On the other hand, the microgroove structure 1.3 with its lateral converging structure directionally diffuses the heat, ensuring uniform heating of the entire liquid film interface and preventing heat accumulation in the center that could lead to drying. In this way, the working fluid is efficiently heated and evaporated, moving to the upper condenser plate 3. After condensation, the working fluid falls back to the MXene-graphene aerogel capillary core plate 2 by gravity. Due to the combination of the high permeability and high capillary pressure of the microgroove structure 1.3 with its lateral converging structure and the MXene-graphene aerogel capillary core plate 2, the working fluid quickly converges to the center of the upper condenser plate 3 to complete the next cycle.

[0086] The directional heat and working fluid circulation loop design ensures uniform and rapid heat diffusion, guaranteeing the rapid evaporation and release of latent heat by the working fluid within the capillary core of the MXene-graphene aerogel capillary core plate 2, and its directional and rapid transport. The overall vapor chamber maintains low thermal resistance while exhibiting excellent temperature uniformity. This invention offers advantages such as good temperature uniformity and high thermal conductivity, making it suitable for meeting the heat dissipation requirements of high heat flux density microprocessors and lightweight equipment needs.

[0087] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A heat spreader based on a high thermal conductivity aerogel / microgroove composite capillary core, characterized in that, It includes a lower evaporation plate (1) and an upper condensation plate (3), which are sealed together. The lower evaporation plate (1) has a hollow cavity inside, and a liquid injection port (1.5) communicating with the hollow cavity is opened on the side wall of the lower evaporation plate (1). It also includes: There are four lateral converging microgroove structures (1.4), and the four lateral converging microgroove structures (1.4) are evenly distributed on the top surface of the lower evaporation plate (1) and are all connected to the hollow cavity. There is a gap between every two adjacent lateral converging microgroove structures (1.4), and every two adjacent lateral converging microgroove structures (1.4) are symmetrical along the gap. All four gaps are connected to the center of the lower evaporation plate (1). The MXene-graphene aerogel capillary core plate (2) is located on the lower evaporation plate (1), and the MXene-graphene aerogel capillary core plate (2) is integrally formed on the lower evaporation plate (1). The MXene-graphene aerogel capillary core plate (2) has four MXene-graphene aerogel capillary cores that are adapted to the four laterally converging microgroove structures (1.4).

2. The heat spreader based on a high thermal conductivity aerogel / microgroove composite capillary core as described in claim 1, characterized in that, The four gaps coincide with the cross-shaped center line of the lower evaporator plate (1).

3. The heat spreader based on a high thermal conductivity aerogel / microgroove composite capillary core as described in claim 2, characterized in that, Each lateral converging microgroove structure (1.4) includes multiple microgrooves that are parallel to each other and equally spaced, with both ends of the multiple microgrooves connected to the gaps on both sides.

4. The heat spreader based on a high thermal conductivity aerogel / microgroove composite capillary core as described in claim 3, characterized in that, Each microgroove forms a 45° angle with the centerline of the lower evaporation plate (1).

5. The heat spreader based on a high thermal conductivity aerogel / microgroove composite capillary core as described in claim 1, characterized in that, The MXene-graphene aerogel capillary core plate (2) is integrally formed with the evaporation lower plate (1) by multiple support columns (1.2). The multiple support columns (1.2) are arranged vertically in each gap. The MXene-graphene aerogel capillary core plate (2) also has multiple grooves that are adapted to the multiple support columns (1.2). The multiple support columns (1.2) are used to make the MXene-graphene aerogel capillary core plate (2) form mechanical support along the height direction.

6. The heat spreader based on a high thermal conductivity aerogel / microgroove composite capillary core as described in claim 5, characterized in that, Multiple support columns (1.2) are evenly distributed in each gap, and the distance between two adjacent support columns (1.2) is 8.5mm. The height of each support column (1.2) is 2mm, and the thickness of the MXene-graphene aerogel capillary core plate (2) is 0.08mm.

7. The heat spreader based on a high thermal conductivity aerogel / microgroove composite capillary core as described in claim 1, characterized in that, The lower evaporator plate (1) has a welding rod groove (1.3) at the top edge of its top wall, and the upper condenser plate (3) and the lower evaporator plate (1) are welded together by welding rods in the welding rod groove (1.3).

8. The heat spreader based on a high thermal conductivity aerogel / microgroove composite capillary core as described in claim 2, characterized in that, The lower evaporation plate (1) and the upper condensation plate (3) are both aluminum-based rectangular plates. The four lateral converging microgroove structures (1.4) are symmetrically arranged in pairs, and the gap between each pair of lateral converging microgroove structures (1.4) coincides with the cross-shaped center line of the lower evaporation plate (1).

9. The method for preparing a heat spreader based on a high thermal conductivity aerogel / microgroove composite capillary core as described in claim 1, characterized in that, Includes the following steps: Four lateral converging microgroove structures (1.4) are fabricated on the top surface of the lower evaporator plate (1); An MXene-graphene aerogel capillary core plate (2) is integrally formed on an evaporation lower plate (1) with four lateral converging microgroove structures (1.4); Then, the upper condenser plate (3) and the lower evaporator plate (1) are sealed together to obtain a heat spreader plate; The processing steps for the integrally formed MXene-graphene aerogel capillary core plate (2) of the evaporation lower plate (1) are as follows: The prepared MXene-graphene solution was poured onto the lower evaporation plate (1) with four lateral converging microgrooves (1.4) and freeze-dried to obtain MXene-graphene aerogel with a thermal conductivity of 25 W / m·K to 30 W / m·K; then the lower evaporation plate (1) with MXene-graphene aerogel was integrally molded and calcined at high temperature.

10. The method for preparing a heat spreader based on a high thermal conductivity aerogel / microgroove composite capillary core as described in claim 9, characterized in that, A titanium layer with a thickness of 40 mm to 50 mm is sputtered onto four lateral converging microgroove structures (1.4). The condenser plate (3) is covered by the evaporation plate (1) with MXene-graphene aerogel and is integrally formed and sealed by high-temperature calcination.

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