A porous suction filter material and its preparation method and application

Abstract

This application relates to the technical field of electronic device components, and particularly to a multi-porous suction filtration material, a preparation method thereof, and an application thereof. The preparation method includes: mixing magnesium-based alloy powder, a part of graphene, and a part of aluminum alloy powder to obtain a first mixed powder; mixing the remaining aluminum alloy powder and the remaining graphene to obtain a second mixed powder; preliminarily performing additive manufacturing on the second mixed powder to obtain a substrate layer; according to a preset wick structure, using the first mixed powder and the second mixed powder to perform gradient additive manufacturing including two-stage additive manufacturing on the surface of the substrate layer to obtain a wick substrate; dissolving and molding the wick substrate in a water vapor environment, and then performing vacuum drying to obtain a multi-porous suction filtration material. This preparation method uses two kinds of mixed powders, combines soluble magnesium-based alloy powder and additive manufacturing technology, and can prepare a wick product with a capillary performance coefficient greater than 5.50×10-6 m, meeting the heat dissipation requirements of electronic chips.

Description

Technical Field

[0001] The present application relates to the technical field of electronic equipment components, and in particular to a porous suction filter material and a preparation method and application thereof. Background Art

[0002] With the increasing power of electronic chips and the pursuit of miniaturization of electronic chips, the heat flux density of electronic chips is increasing. The higher the operating temperature of electronic chips, the more serious their failure problem will be. Therefore, at this stage, it is necessary to explore the heat dissipation components and equipment of electronic chips. At present, the commonly used heat dissipation equipment for electronic chips is mainly air cooling. Compared with traditional air-cooled radiators, the new flat heat pipe is based on the principle of phase change heat transfer, has higher heat dissipation capacity and efficiency, and can meet the heat dissipation requirements of high-power electronic components. The key component of the flat heat pipe is the wick structure. Through the capillary action of the wick, liquid can be transferred without the participation of external power. If the wick is to have good capillary properties, the wick is required to have a small effective pore size and a high permeability. The raw materials of traditional liquid absorbent cores are generally metal wire mesh, sintered metal powder and metal fiber. By directly stacking metal wire mesh or metal fiber into core material, or sintering metal powder through high temperature sintering, a liquid absorbent core with smaller effective pore size and higher permeability can be formed. However, due to the characteristics of the metal wire mesh and metal fiber themselves, they are very easy to bend or even break after stacking and use, and adhesion will occur during the liquid absorption process, reducing the liquid absorption capacity of the liquid absorbent core; in addition, the liquid absorbent core formed by sintering metal powder has a relatively simple structure and is difficult to prepare to cope with complex flat heat pipe shapes and working requirements; in addition, the size of the pore structure formed by sintering metal powder is difficult to fix, which will undoubtedly affect the normal operation of the liquid absorbent core.

[0003] For these problems existing in traditional wicks, additive manufacturing technology can be used to prepare wicks at this stage. However, when preparing complex wick structures, it is difficult to obtain wick products with sufficient precision using additive manufacturing technology. In addition, general additive manufacturing technology will cause pore blockage when preparing fine pore structures (0.001mm~0.2mm). For such fine pore structures, only fine printing technology can be used, which will undoubtedly increase the preparation cost of the wick. Therefore, traditional additive manufacturing technology can only prepare larger and evenly distributed pore structures, and it is difficult to obtain relatively small and regular pore structures. Summary of the invention

[0004] The present application provides a porous suction filter material and a preparation method and application thereof to solve the following technical problem: how to obtain a liquid-absorbing core with fine pore structure and uniform arrangement.

[0005] In a first aspect, the present application provides a method for preparing a porous suction filter material, the preparation method comprising:

[0006] Mixing magnesium-based alloy powder, part of graphene and part of aluminum alloy powder to obtain a first mixed powder;

[0007] Mixing the remaining aluminum alloy powder and the remaining graphene to obtain a second mixed powder;

[0008] Performing preliminary additive manufacturing on the second mixed powder to obtain a substrate layer;

[0009] According to the preset liquid wick structure, the first mixed powder and the second mixed powder are used to perform gradient additive manufacturing on the surface of the substrate layer to obtain a liquid wick substrate with a multi-layer overlapping structure; wherein the gradient additive manufacturing includes a first-level additive manufacturing and a second-level additive manufacturing, the first-level additive manufacturing is used for molding the first mixed powder, and the second-level additive manufacturing is used for molding the second mixed powder;

[0010] The liquid absorbent core substrate is dissolved and formed in a water vapor environment, and then vacuum dried to obtain a porous filter material.

[0011] Optionally, the laser power of the first-level additive manufacturing is 100W-150W, the scanning speed of the first-level additive manufacturing is 800mm / s-1200mm / s, the scanning pitch of the first-level additive manufacturing is 80μm-120μm, the layer thickness of the first-level additive manufacturing is 15μm-25μm, and the spot diameter of the first-level additive manufacturing is 5μm-10μm; and / or

[0012] The laser power of the second-level additive manufacturing is 180W-200W, the scanning speed of the second-level additive manufacturing is 1400mm / s-1600mm / s, the scanning pitch of the second-level additive manufacturing is 150μm-180μm, the layer thickness of the second-level additive manufacturing is 55μm-65μm, and the spot diameter of the second-level additive manufacturing is 25μm-35μm; and / or

[0013] The laser power of the preliminary additive manufacturing is 180W to 200W, the scanning speed of the preliminary additive manufacturing is 1400mm / s to 1600mm / s, the scanning spacing of the preliminary additive manufacturing is 150μm to 180μm, the layer thickness of the preliminary additive manufacturing is 55μm to 65μm, and the spot diameter of the preliminary additive manufacturing is 25μm to 35μm.

[0014] Optionally, the method of using the first mixed powder and the second mixed powder to perform gradient additive manufacturing on the surface of the substrate layer according to the preset liquid absorbent core structure to obtain a liquid absorbent core substrate with a multi-layer overlapping structure comprises the following steps:

[0015] According to the preset liquid wick structure, the first mixed powder is laid on the surface of the substrate layer to perform the first-level additive manufacturing to obtain a first functional layer;

[0016] Laying the second mixed powder on the surface of the first functional layer to perform the second-level additive manufacturing to obtain a second functional layer;

[0017] The first-level additive manufacturing and the second-level additive manufacturing processes are repeated to form a plurality of the first functional layers and a plurality of the second functional layers on the surface of the substrate layer, and the second functional layer is located at the outermost layer, so as to obtain a liquid-absorbing core substrate with a multi-layer overlapping structure.

[0018] Optionally, the mass ratio of the magnesium-based alloy powder, part of the graphene and part of the aluminum alloy powder is (20-30): (10-20): 100; and / or

[0019] The mass ratio of the remaining aluminum alloy powder to the remaining graphene is 100:(5-15).

[0020] Optionally, the particle size of the magnesium-based alloy powder is 5 μm to 10 μm, the particle size of the graphene is 15 μm to 30 μm, and the particle size of the aluminum alloy powder is 25 μm to 50 μm.

[0021] Optionally, the water vapor environment is a mixed gas of water vapor and an inert gas, and the volume ratio of the water vapor to the inert gas is (15-25): (85-75); and / or

[0022] The flow rate of the mixed gas is 100 mL / min to 150 mL / min.

[0023] Optionally, the temperature of the dissolution molding is 85°C to 95°C, and the time of the dissolution molding is 20min to 40min.

[0024] Optionally, the preset wick structure includes a lattice structure having a plurality of pores of different shapes, and the different shapes include at least one of the following: triangle, quadrilateral, pentagon and hexagon.

[0025] In a second aspect, the present application provides a porous suction filter material, wherein the porous suction filter material is prepared by the preparation method described in the first aspect.

[0026] In a third aspect, the present application provides a flat-plate heat pipe, which includes the porous suction filter material described in the second aspect or includes the porous suction filter material prepared by the preparation method described in the first aspect.

[0027] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0028] The present application provides a method for preparing a porous filter material, which uses magnesium-based alloy powder, graphene and aluminum alloy as raw materials to form a first mixed powder, and then uses aluminum alloy powder and graphite phase as raw materials to form a second mixed powder, and then performs preliminary additive manufacturing on the second mixed powder. Since the second mixed powder including aluminum alloy powder and graphene is used, a small amount of aluminum alloy powder can be melted to form a molten metal during the preliminary additive manufacturing process, and the addition of graphene can accelerate the flow of the financial solution formed by the aluminum alloy powder on the one hand, and on the other hand, it can also be added to the aluminum alloy powder as a solid phase particle to optimize the particle distribution of the aluminum alloy powder and form a relatively fine pore structure; in addition, according to the preset liquid wick structure, the first mixed powder and the second mixed powder are used as raw materials, and the gradient additive manufacturing method is used. The method is to distribute two functional layers of different thicknesses and structures on the substrate layer in a gradient manner, so that a wick substrate with an expected thickness and structure can be obtained; then the obtained wick substrate is dissolved and formed in a water vapor environment, and based on the solubility of the magnesium-based alloy powder of the first mixed powder, the magnesium-based alloy powder of the wick substrate will dissolve to form salt in a water vapor environment, so that a dense pore structure with gap distribution is formed on the surface of the wick substrate, so that a wick structure with a fine pore structure can be obtained; in addition, the water vapor environment will also passivate part of the aluminum alloy powder to form a stable passivation layer structure, which can not only improve the flatness of the fine pore structure formed by dissolution molding to stabilize these fine pore structures, but also improve the strength of the fine pore structure to ensure the normal function of the fine pore structure in the wick. Therefore, the preparation method can prepare a wick product with a fine pore structure and uniform arrangement by combining two different mixed powders, the solubility of the magnesium-based alloy powder and the additive manufacturing technology to meet the heat dissipation requirements of high-power miniaturized electronic chips. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0031] Figure 1 A schematic diagram of a method for preparing a porous suction filter material provided in an embodiment of the present application;

[0032] Figure 2 A detailed schematic diagram of a method for preparing a porous suction filter material provided in an embodiment of the present application;

[0033] Figure 3 A schematic diagram of the structure of two functional layers of a porous filtration material provided in an embodiment of the present application. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0035] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity and should not be understood as a rigid limitation on the scope of the present application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within the range; for example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which applies regardless of the range; in addition, whenever a numerical range is indicated in this document, it is meant to include any cited numbers (fractions or integers) within the indicated range.

[0036] In this document, the terms including "including" and "including" mean "including but not limited to". Relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. "And / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone; where A and B can be singular or plural. "At least one" means one or more, "plurality" means two or more; "at least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items; for example, "at least one of a, b, or c", or "at least one of a, b, and c" can all mean: a, b, c, ab (i.e. a and b), ac, bc, or abc, where a, b, and c can be single or plural, respectively. "Parts" such as parts by weight and parts by mass indicate the proportional relationship between the components. In the proportional relationship involved in this article, the parameters that need to be described by proportion should be understood as the first term of the proportional formula in the order of description, and the proportional numbers should be understood as the second term of the proportional formula. For example, if the mass ratio of substance A, substance B and substance C is 1:2:3, then substance A, substance B and substance C should correspond to the proportional numbers in the proportional formula in the order of description, that is, the mass of substance A: the mass of substance B: the mass of substance C = 1:2:3.

[0037] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this article can be purchased from the market or prepared by existing methods.

[0038] Figure 1 A schematic diagram of a process for preparing a porous suction filter material provided in an embodiment of the present application is exemplarily shown;

[0039] Figure 3 The schematic diagram of the structure of two functional layers of a porous suction filter material provided in an embodiment of the present application is exemplarily shown;

[0040] like Figure 1 As shown, the present application embodiment provides a method for preparing a porous suction filter material, the preparation method comprising:

[0041] S1. Mixing a magnesium-based alloy powder, a portion of graphene and a portion of an aluminum alloy powder to obtain a first mixed powder;

[0042] S2. mixing the remaining aluminum alloy powder and the remaining graphene to obtain a second mixed powder;

[0043] S3. performing preliminary additive manufacturing on the second mixed powder to obtain a substrate layer;

[0044] S4. According to the preset liquid wick structure, the first mixed powder and the second mixed powder are used to perform gradient additive manufacturing on the surface of the substrate layer to obtain a liquid wick substrate with a multi-layer overlapping structure; wherein the gradient additive manufacturing includes a first-level additive manufacturing and a second-level additive manufacturing, the first-level additive manufacturing is used for molding the first mixed powder, and the second-level additive manufacturing is used for molding the second mixed powder;

[0045] S5. Dissolving and molding the liquid absorbent core substrate in a water vapor environment, and then vacuum drying to obtain a porous filter material.

[0046] It should be noted that, in terms of mass fraction, the chemical composition of the magnesium-based alloy powder may be: magnesium: 80% to 95%, aluminum: 3% to 19%, zinc: 0.5% to 3%, chromium: 0.05% to 0.10%, and the rest are unavoidable impurities. In addition, the dissolution rate of the magnesium-based alloy powder in a potassium chloride solution with a mass concentration of 3% at room temperature is 25 mg·cm to 30 mg·cm.

[0047] It should be noted that the mixing method can be mechanical stirring, magnetic stirring, or grinding.

[0048] It should be noted that the general process of the first-level additive manufacturing and the second-level additive manufacturing can be carried out with reference to the general process described in CN202410368681.0.

[0049] It should be noted that the present application embodiment provides a method for preparing a porous suction filter material, which is an innovative and valuable process. Specifically:

[0050] (1) First, magnesium-based alloy powder, graphene and aluminum alloy are selected as basic raw materials, and the first mixed powder is prepared through precise proportioning and mixing process. Among them, magnesium-based alloy powder plays a key role in the subsequent process steps due to its unique physical and chemical properties; graphene brings more functionality and optimization possibilities to the entire material system due to its excellent conductivity, high strength and high toughness. At the same time, aluminum alloy powder and graphite phase are used as raw materials to form the second mixed powder through a specific mixing process. Aluminum alloy powder has good plasticity and metallic properties, while graphite phase has stable chemical properties and special structure. The combination of the two gives the second mixed powder special properties.

[0051] (2) Next, the second mixed powder is subjected to preliminary additive manufacturing. In this process, since the second mixed powder contains aluminum alloy powder and graphene, a small amount of aluminum alloy powder will melt and transform into molten metal under the temperature conditions of additive manufacturing. The addition of graphene has multiple important meanings: on the one hand, it can accelerate the flow rate of the molten metal formed by the aluminum alloy powder with its own high thermal conductivity and special atomic structure, making the molten metal more evenly distributed during the molding process; on the other hand, graphene, as a solid phase particle, can be evenly incorporated into the aluminum alloy powder, effectively optimizing the particle distribution of the aluminum alloy powder, thereby promoting the formation of the material. Figure 3 The relatively small and evenly distributed pore structure shown in the figure. This unique pore structure lays a solid foundation for the subsequent improvement of material performance.

[0052] (3) Then, according to the pre-designed wick structure, the first mixed powder and the second mixed powder are used as raw materials, and the gradient additive manufacturing technology is used to perform a fine gradient distribution operation on the substrate layer to construct two functional layers with different thicknesses and structures. By precisely controlling the parameters in the additive manufacturing process, such as temperature, pressure, material delivery speed, etc., it is ensured that the thickness and structure of each functional layer can accurately meet the expected design requirements, thereby successfully preparing a wick substrate with just the right thickness and structure.

[0053] (4) Subsequently, the obtained liquid absorbent core substrate is placed in a water vapor environment for dissolution molding. Based on the key characteristic of the solubility of the magnesium-based alloy powder in the first mixed powder, the magnesium-based alloy powder in the liquid absorbent core substrate will react chemically with the water vapor in the water vapor environment and gradually dissolve to form salt substances. This process causes the surface of the liquid absorbent core substrate to form a gap distribution such as Figure 3 The dense pore structure shown in the figure is extremely small, which greatly improves the absorption and filtration performance of the absorbent core. In addition, the water vapor environment will also affect the aluminum alloy powder, causing it to partially undergo a passivation reaction, thereby forming a stable passivation layer structure on the surface of the material. These passivation layer structures have multiple functions. They can not only significantly improve the flatness of the fine pore structure formed during the dissolution molding process and ensure the stability of these fine pore structures; they can also effectively improve the strength of the fine pore structure, so that it can withstand a certain amount of pressure and external force during the normal use of the absorbent core, ensuring that the absorbent core can function normally and meet the heat dissipation needs of high-power and miniaturized electronic chips.

[0054] In summary, this preparation method cleverly utilizes two different mixed powders, fully combines the solubility of magnesium-based alloy powders and advanced additive manufacturing technology, and successfully achieves the preparation of a liquid absorbent core product with fine pore structure and uniform arrangement. This liquid absorbent core product has broad application prospects and potential practical value in many fields, such as aerospace, electronic equipment heat dissipation, chemical filtration, etc., and can be especially suitable for heat dissipation equipment for electronic chips.

[0055] In some optional embodiments, the laser power of the first-level additive manufacturing is 100W-150W, the scanning speed of the first-level additive manufacturing is 800mm / s-1200mm / s, the scanning pitch of the first-level additive manufacturing is 80μm-120μm, the layer thickness of the first-level additive manufacturing is 15μm-25μm, and the spot diameter of the first-level additive manufacturing is 5μm-10μm; and / or

[0056] The laser power of the second-level additive manufacturing is 180W-200W, the scanning speed of the second-level additive manufacturing is 1400mm / s-1600mm / s, the scanning pitch of the second-level additive manufacturing is 150μm-180μm, the layer thickness of the second-level additive manufacturing is 55μm-65μm, and the spot diameter of the second-level additive manufacturing is 25μm-35μm; and / or

[0057] The laser power of the preliminary additive manufacturing is 180W to 200W, the scanning speed of the preliminary additive manufacturing is 1400mm / s to 1600mm / s, the scanning spacing of the preliminary additive manufacturing is 150μm to 180μm, the layer thickness of the preliminary additive manufacturing is 55μm to 65μm, and the spot diameter of the preliminary additive manufacturing is 25μm to 35μm.

[0058] In these embodiments, the laser power of the first-level additive manufacturing can be 100W to 150W, and the scanning speed of the first-level additive manufacturing can be 800mm / s to 1200mm / s, and the scanning pitch of the first-level additive manufacturing can be 80μm to 120μm, and the layer thickness of the first-level additive manufacturing can be 15μm to 25μm, and the spot diameter of the first-level additive manufacturing can be 5μm to 10μm, so that the first mixed powder can form a first functional layer structure with sufficient thickness and uniform distribution of components through the first-level additive manufacturing method; in addition, the laser power of the second-level additive manufacturing can be 180W to 200W, and the scanning speed of the second-level additive manufacturing can be 1400mm / s to 1600mm / s, and the scanning pitch of the second-level additive manufacturing can be 150 μm~180μm, and the layer thickness of the second-level additive manufacturing can be 55μm~65μm, and the spot diameter of the second-level additive manufacturing can be 25μm~35μm, so that the second mixed powder can form a second functional layer structure with sufficient thickness and uniform composition distribution through the second-level additive manufacturing method; in addition, the laser power of the preliminary additive manufacturing can be 180W~200W, and the scanning speed of the preliminary additive manufacturing can be 1400mm / s~1600mm / s, and the scanning spacing of the preliminary additive manufacturing can be 150μm~180μm, and the layer thickness of the preliminary additive manufacturing can be 55μm~65μm, and the spot diameter of the preliminary additive manufacturing can be 25μm~35μm, so that the second mixed powder can form a substrate layer with sufficient thickness and uniform composition through the preliminary additive manufacturing.

[0059] The laser power for this first stage additive manufacturing may be 100W, 110W, 120W, 130W, 140W or 150W.

[0060] The scanning speed of the first level additive manufacturing can be 800mm / s, 850mm / s, 900mm / s, 950mm / s, 1000mm / s, 1050mm / s, 1100mm / s, 1150mm / s or 1200mm / s.

[0061] The scanning pitch of the first level additive manufacturing can be 80μm, 90μm, 100μm, 110μm or 120μm.

[0062] The layer thickness of this first level additive manufacturing may be 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm or 25 μm.

[0063] The spot diameter of the first-stage additive manufacturing can be 5μm, 6μm, 7μm, 8μm, 9μm or 10μm.

[0064] The laser power for this second-stage additive manufacturing can be 180W, 185W, 190W, 195W or 200W.

[0065] The scanning speed of the second level additive manufacturing can be 1400mm / s, 1450mm / s, 1500mm / s, 1550mm / s or 1600mm / s.

[0066] The scanning pitch of the second level additive manufacturing may be 150 μm, 155 μm, 160 μm, 165 μm, 170 μm, 175 μm or 180 μm.

[0067] The layer thickness of the second stage additive manufacturing can be 55μm, 56μm, 57μm, 58μm, 59μm, 60μm, 61μm, 62μm, 63μm, 64μm or 65μm.

[0068] The spot diameter of the second-level additive manufacturing can be 25μm, 26μm, 27μm, 28μm, 29μm, 30μm, 31μm, 32μm, 33μm, 34μm or 35μm.

[0069] The laser power for this initial additive manufacturing can be 180W, 185W, 190W, 195W or 200W.

[0070] The scanning speed of the preliminary additive manufacturing can be 1400 mm / s, 1450 mm / s, 1500 mm / s, 1550 mm / s or 1600 mm / s.

[0071] The scan pitch of the preliminary additive manufacturing may be 150 μm, 155 μm, 160 μm, 165 μm, 170 μm, 175 μm or 180 μm.

[0072] The layer thickness of the preliminary additive manufacturing can be 55 μm, 56 μm, 57 μm, 58 μm, 59 μm, 60 μm, 61 μm, 62 μm, 63 μm, 64 μm or 65 μm.

[0073] The spot diameter of the preliminary additive manufacturing can be 25μm, 26μm, 27μm, 28μm, 29μm, 30μm, 31μm, 32μm, 33μm, 34μm or 35μm.

[0074] Figure 2 A schematic diagram of a process for preparing a porous suction filter material provided in an embodiment of the present application is exemplarily shown;

[0075] In some optional embodiments, such as Figure 2As shown, according to the preset liquid absorbent core structure, the first mixed powder and the second mixed powder are used to perform gradient additive manufacturing on the surface of the substrate layer to obtain a liquid absorbent core substrate with a multi-layer overlapping structure, including the steps of:

[0076] S401. According to the preset wick structure, the first mixed powder is laid on the surface of the substrate layer to perform the first level additive manufacturing to obtain a first functional layer;

[0077] S402. Laying the second mixed powder on the surface of the first functional layer to perform the second-level additive manufacturing to obtain a second functional layer;

[0078] S403. Repeat the first-level additive manufacturing and the second-level additive manufacturing processes to form a plurality of the first functional layers and a plurality of the second functional layers on the surface of the substrate layer, with the second functional layer being located at the outermost layer, to obtain a liquid-absorbing core substrate with a multi-layer overlapping structure.

[0079] In these embodiments, a first mixed powder is first laid on the surface of a substrate layer for a first-level additive manufacturing to obtain a first functional layer, and then a second mixed powder is laid on the surface of the first functional layer for a second-level additive manufacturing to obtain a second functional layer. Then, by repeating these first-level additive manufacturing and second-level additive manufacturing steps, a plurality of overlapping layered structures can be formed on the surface of the substrate layer to obtain a wick substrate having a preset wick structure.

[0080] In some optional embodiments, the mass ratio of the magnesium-based alloy powder, part of the graphene and part of the aluminum alloy powder is (20-30): (10-20): 100; and / or

[0081] The mass ratio of the remaining aluminum alloy powder to the remaining graphene is 100:(5-15).

[0082] In these embodiments, the mass ratio of the magnesium-based alloy powder, part of the graphene and part of the aluminum alloy powder can be (20-30): (10-20): 100, so that the magnesium-based alloy powder, the graphene and the aluminum alloy powder are fully mixed, and a sufficient amount of magnesium-based alloy powder is provided in the first functional layer, and the sufficient amount of magnesium-based alloy powder can be dissolved in a water vapor environment and separated from the liquid absorbent core substrate, so that a dense pore structure with interstitial distribution can be formed on the surface of the liquid absorbent core substrate, and these pore structures are extremely fine, which greatly improves the liquid absorption and filtration performance of the liquid absorbent core; in addition The mass ratio of the remaining aluminum alloy powder to the remaining graphene can be 100:(5-15), so that the aluminum alloy powder has a sufficient amount of graphene. On the one hand, the sufficient amount of graphene can accelerate the flow rate of the molten metal formed by the aluminum alloy powder by virtue of its own high thermal conductivity and special atomic structure, so that the molten metal is more evenly distributed during the forming process; on the other hand, the sufficient amount of graphene can be used as solid phase particles and can be evenly incorporated into the aluminum alloy powder, effectively optimizing the particle distribution of the aluminum alloy powder, thereby promoting the formation of a relatively small and evenly distributed pore structure inside the material.

[0083] The mass of the magnesium-based alloy powder can be 20, 21, 22, 23, 24, 25, 26, 27, 28, 29 or 30.

[0084] The mass of the portion of graphene can be 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20.

[0085] The value of the mass of the remaining graphene can be 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15.

[0086] In some optional embodiments, the particle size of the magnesium-based alloy powder is 5 μm to 10 μm, the particle size of the graphene is 15 μm to 30 μm, and the particle size of the aluminum alloy powder is 25 μm to 50 μm.

[0087] In these embodiments, the particle size of the magnesium-based alloy powder can be 5μm to 10μm, the particle size of the graphene can be 15μm to 30μm, and the particle size of the aluminum alloy powder can be 25μm to 50μm, so that the magnesium-based alloy powder, graphene and aluminum alloy powder have sufficiently fine particle sizes. Sufficiently fine graphene and aluminum alloy powders can form a sufficiently dense substrate layer and a second functional layer. In addition, sufficiently fine magnesium-based alloy powders will fully react with water vapor during the dissolution and molding stage to form an intermittently distributed dense pore structure on the surface of the wick substrate. These pore structures can greatly improve the wicking performance of the wick, so that the wick can meet the heat dissipation requirements of high-power and miniaturized electronic chips.

[0088] The particle size of the magnesium-based alloy powder may be 5 μm, 6 μm, 7 μm, 8 μm, 9 μm or 10 μm.

[0089] The particle size of the graphene may be 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 25 μm or 30 μm.

[0090] The particle size of the aluminum alloy powder may be 25 μm, 30 μm, 35 μm, 40 μm, 45 μm or 50 μm.

[0091] In some optional embodiments, the water vapor environment is a mixed gas of water vapor and an inert gas, and the volume ratio of the water vapor to the inert gas is (15-25): (85-75); and / or

[0092] The flow rate of the mixed gas is 100 mL / min to 150 mL / min.

[0093] In these embodiments, the water vapor environment is a mixed gas of water vapor and an inert gas, and the volume ratio of water vapor to inert gas can be (15-25): (85-75), so that the mixed gas has sufficient water vapor. On the one hand, sufficient water vapor can cause the magnesium-based alloy powder in the absorbent core substrate to gradually dissolve to form salt substances, so that the surface of the absorbent core substrate forms an intermittently distributed dense and fine pore structure, and these pore structures can greatly improve the liquid absorption and filtration performance of the absorbent core; on the other hand, sufficient water vapor will also affect the aluminum alloy powder, causing it to partially undergo a passivation reaction, thereby forming a stable passivation layer structure on the surface of the material. These passivation layer structures have multiple functions, which can not only significantly improve the flatness of the fine pore structure formed during the dissolution molding process, ensure the stability of these fine pore structures, but also effectively improve the strength of the fine pore structure, so that it can withstand a certain pressure and external force during the normal use of the absorbent core, and ensure that the absorbent core can function normally. In addition, the flow rate of the mixed gas can be 100 mL / min to 150 mL / min, so that the water vapor of the mixed gas can fully contact with the magnesium-based alloy powder, so as to promote the dissolution of the magnesium-based alloy powder and form salt substances, thereby promoting the formation of intermittently distributed dense and fine pore structures on the surface of the liquid absorbent core substrate. These pore structures can greatly improve the liquid absorption and filtration performance of the liquid absorbent core, so that the liquid absorbent core can meet the heat dissipation requirements of high-power and miniaturized electronic chips.

[0094] The volume of the water vapor can be 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 or 25.

[0095] The volume of the inert gas can be 85, 84, 83, 82, 81, 80, 79, 78, 77, 76 or 75.

[0096] The flow rate of the mixed gas can be 100 mL / min, 105 mL / min, 110 mL / min, 115 mL / min, 120 mL / min, 125 mL / min, 130 mL / min, 135 mL / min, 140 mL / min, 145 mL / min or 150 mL / min.

[0097] In some optional embodiments, the dissolution molding temperature is 85°C to 95°C, and the dissolution molding time is 20min to 40min.

[0098] In these embodiments, the dissolution molding temperature can be 85° C. to 95° C., and the dissolution molding time can be 20 min to 40 min, so that the magnesium-based alloy powder in the wick substrate is gradually dissolved to form salt substances, so that the surface of the wick substrate forms an intermittently distributed dense and fine pore structure, and these pore structures can greatly improve the wick's liquid absorption and filtration performance; in addition, the dissolution molding can also promote the passivation reaction of the aluminum alloy powder, thereby forming a stable passivation layer structure on the material surface to stabilize the pore structure of the wick substrate.

[0099] The temperature of the dissolution molding may be 85°C, 86°C, 87°C, 88°C, 89°C, 90°C, 91°C, 92°C, 93°C, 94°C or 95°C.

[0100] The dissolution and molding time can be 20 min, 25 min, 30 min, 35 min or 40 min.

[0101] In some optional embodiments, the preset wick structure includes a lattice structure having a plurality of pores of different shapes, and the different shapes include at least one of the following: triangle, quadrilateral, pentagon and hexagon.

[0102] In these embodiments, the preset absorbent core structure may include a lattice structure having multiple pores of different shapes, and the different shapes include at least one of the following: triangle, quadrilateral, pentagon and hexagon. Different shapes can be set according to the actual absorbent core structure to meet the actual use requirements of the absorbent core.

[0103] Based on a general inventive concept, an embodiment of the present application provides a porous suction filter material, and the porous suction filter material is prepared by the preparation method.

[0104] The porous suction filter material is prepared based on the above-mentioned preparation method. The specific steps of the preparation method can refer to the above-mentioned embodiment. Since the porous suction filter material adopts part or all of the technical solutions of the above-mentioned embodiment, it at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiment, which will not be repeated here one by one.

[0105] Based on a general inventive concept, an embodiment of the present application provides a flat-plate heat pipe, which includes the porous suction filter material or the porous suction filter material prepared by the preparation method.

[0106] The flat plate heat pipe is realized based on the above-mentioned porous suction filter material or preparation method. The composition of the porous suction filter material or the specific steps of the preparation method can refer to the above-mentioned embodiments. Since the flat plate heat pipe adopts part or all of the technical solutions of the above-mentioned embodiments, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be repeated here one by one.

[0107] The present application is further described below in conjunction with specific examples. The experimental methods in the following examples where specific conditions are not specified are usually measured in accordance with national standards / industry standards; if there are no corresponding national standards / industry standards, they are measured in accordance with common international standards, conventional conditions or conditions recommended by the manufacturer.

[0108] Example 1

[0109] like Figure 2 As shown, a method for preparing a porous suction filter material comprises:

[0110] S1. Mixing a magnesium-based alloy powder, a portion of graphene and a portion of an aluminum alloy powder to obtain a first mixed powder;

[0111] S2. mixing the remaining aluminum alloy powder and the remaining graphene to obtain a second mixed powder;

[0112] S3. Preliminary additive manufacturing of the second mixed powder to obtain a substrate layer;

[0113] S401. According to the preset wick structure, the first mixed powder is laid on the surface of the substrate layer to perform the first level of additive manufacturing to obtain a first functional layer;

[0114] S402. Laying the second mixed powder on the surface of the first functional layer to perform a second level of additive manufacturing to obtain a second functional layer;

[0115] S403. Repeat the process of the first-level additive manufacturing and the second-level additive manufacturing to form a plurality of first functional layers and a plurality of second functional layers on the surface of the substrate layer, and the second functional layer is located at the outermost layer, to obtain a liquid absorbent core substrate with a multi-layer overlapping structure; wherein the gradient additive manufacturing includes the first-level additive manufacturing and the second-level additive manufacturing, the first-level additive manufacturing is used for the first mixed powder molding, and the second-level additive manufacturing is used for the second mixed powder molding;

[0116] S5. Dissolving and molding the liquid absorbent core substrate in a water vapor environment, and then vacuum drying to obtain a porous filter material.

[0117] The laser power of the first-level additive manufacturing is 130W, the scanning speed of the first-level additive manufacturing is 1000mm / s, the scanning pitch of the first-level additive manufacturing is 100μm, the layer thickness of the first-level additive manufacturing is 20μm, and the spot diameter of the first-level additive manufacturing is 8μm;

[0118] The laser power of the second-level additive manufacturing is 190W, the scanning speed of the second-level additive manufacturing is 1500mm / s, the scanning pitch of the second-level additive manufacturing is 170μm, the layer thickness of the second-level additive manufacturing is 60μm, and the spot diameter of the second-level additive manufacturing is 30μm;

[0119] The laser power of the preliminary additive manufacturing is 185W, the scanning speed of the preliminary additive manufacturing is 1450mm / s, the scanning pitch of the preliminary additive manufacturing is 160μm, the layer thickness of the preliminary additive manufacturing is 60μm, and the spot diameter of the preliminary additive manufacturing is 28μm.

[0120] The mass ratio of magnesium-based alloy powder, part of graphene and part of aluminum alloy powder is 25:15:100;

[0121] The mass ratio of the remaining aluminum alloy powder to the remaining graphene is 100:10.

[0122] The particle size of the magnesium-based alloy powder is 5 μm to 10 μm, the particle size of the graphene is 15 μm to 30 μm, and the particle size of the aluminum alloy powder is 25 μm to 50 μm.

[0123] The water vapor environment is a mixture of water vapor and inert gas, and the volume ratio of water vapor to inert gas is 20:80;

[0124] The flow rate of the mixed gas was 130 mL / min.

[0125] The temperature for dissolving and molding was 90°C, and the time for dissolving and molding was 30 minutes.

[0126] The preset wick structure includes a lattice structure having quadrilateral pores.

[0127] Example 2

[0128] Based on the contents disclosed in Example 1, the following modifications are further made:

[0129] The laser power of the first-level additive manufacturing is 100W, the scanning speed of the first-level additive manufacturing is 800mm / s, the scanning pitch of the first-level additive manufacturing is 80μm, the layer thickness of the first-level additive manufacturing is 15μm, and the spot diameter of the first-level additive manufacturing is 5μm;

[0130] The laser power of the second-level additive manufacturing is 180W, the scanning speed of the second-level additive manufacturing is 1400mm / s, the scanning pitch of the second-level additive manufacturing is 150μm, the layer thickness of the second-level additive manufacturing is 55μm, and the spot diameter of the second-level additive manufacturing is 25μm;

[0131] The laser power of the preliminary additive manufacturing is 180W, the scanning speed of the preliminary additive manufacturing is 1400mm / s, the scanning pitch of the preliminary additive manufacturing is 150μm, the layer thickness of the preliminary additive manufacturing is 55μm, and the spot diameter of the preliminary additive manufacturing is 25μm.

[0132] Example 3

[0133] Based on the contents disclosed in Example 1, the following modifications are further made:

[0134] The laser power of the first-level additive manufacturing is 150W, the scanning speed of the first-level additive manufacturing is 1200mm / s, the scanning pitch of the first-level additive manufacturing is 120μm, the layer thickness of the first-level additive manufacturing is 25μm, and the spot diameter of the first-level additive manufacturing is 10μm;

[0135] The laser power of the second-level additive manufacturing is 200W, the scanning speed of the second-level additive manufacturing is 1600mm / s, the scanning pitch of the second-level additive manufacturing is 180μm, the layer thickness of the second-level additive manufacturing is 65μm, and the spot diameter of the second-level additive manufacturing is 35μm;

[0136] The laser power of the preliminary additive manufacturing is 200W, the scanning speed of the preliminary additive manufacturing is 1600mm / s, the scanning pitch of the preliminary additive manufacturing is 180μm, the layer thickness of the preliminary additive manufacturing is 65μm, and the spot diameter of the preliminary additive manufacturing is 35μm.

[0137] Example 4

[0138] Based on the contents disclosed in Example 1, the following modifications are further made:

[0139] The mass ratio of magnesium-based alloy powder, part of graphene and part of aluminum alloy powder is 30:20:100;

[0140] The mass ratio of the remaining aluminum alloy powder to the remaining graphene is 100:15.

[0141] Example 5

[0142] Based on the contents disclosed in Example 1, the following modifications are further made:

[0143] The mass ratio of magnesium-based alloy powder, part of graphene and part of aluminum alloy powder is 20:10:100;

[0144] The mass ratio of the remaining aluminum alloy powder to the remaining graphene is 100:5.

[0145] Example 6

[0146] Based on the contents disclosed in Example 1, the following modifications are further made:

[0147] The volume ratio of water vapor to inert gas is 15:85;

[0148] The flow rate of the mixed gas was 100 mL / min.

[0149] The temperature for dissolving and molding was 85°C, and the time for dissolving and molding was 20 minutes.

[0150] Example 7

[0151] Based on the contents disclosed in Example 1, the following modifications are further made:

[0152] The volume ratio of water vapor to inert gas is 25:75;

[0153] The flow rate of the mixed gas was 150 mL / min.

[0154] The temperature for dissolving and molding was 95°C, and the time for dissolving and molding was 40 minutes.

[0155] Comparative Example 1

[0156] Based on the contents disclosed in Example 1, the following modifications are further made:

[0157] No magnesium-based alloy powder is added.

[0158] Comparative Example 2

[0159] Based on the contents disclosed in Example 1, the following modifications are further made:

[0160] The mass ratio of magnesium-based alloy powder, part of graphene and part of aluminum alloy powder is 10:5:100;

[0161] The mass ratio of the remaining aluminum alloy powder to the remaining graphene is 100:0.

[0162] Comparative Example 3

[0163] Based on the contents disclosed in Example 1, the following modifications are further made:

[0164] The mass ratio of magnesium-based alloy powder, part of graphene and part of aluminum alloy powder is 40:30:100;

[0165] The mass ratio of the remaining aluminum alloy powder to the remaining graphene is 100:20.

[0166] Comparative Example 4

[0167] Based on the contents disclosed in Example 1, the following modifications are further made:

[0168] The volume ratio of water vapor to inert gas is 10:90.

[0169] Comparative Example 5

[0170] Based on the contents disclosed in Example 1, the following modifications are further made:

[0171] The volume ratio of water vapor to inert gas is 30:70.

[0172] Comparative Example 6

[0173] Based on the contents disclosed in Example 1, the following modifications are further made:

[0174] The flow rate of the mixed gas was 80 mL / min.

[0175] Comparative Example 7

[0176] Based on the contents disclosed in Example 1, the following modifications are further made:

[0177] The flow rate of the mixed gas was 200 mL / min.

[0178] Comparative Example 8

[0179] Based on the contents disclosed in Example 1, the following modifications are further made:

[0180] The temperature for dissolving and molding was 80°C, and the time for dissolving and molding was 50 minutes.

[0181] Comparative Example 9

[0182] Based on the contents disclosed in Example 1, the following modifications are further made:

[0183] The temperature of the dissolution molding is 100°C, and the time of the dissolution molding is 20 minutes.

[0184] Related experiments and effect data:

[0185] The porous suction filtration materials obtained in each embodiment and comparative example were analyzed using the capillary rise method, and the relationship curves between the liquid absorption mass and time were statistically obtained. Then, these relationship curves were fitted in combination with the mt model, and the permeability K and the effective pore radius Reff were directly calculated according to the fitting formula to obtain the capillary performance coefficient K / Reff. The specific measurement process was carried out according to the contents described in CN202410368681.0, and the capillary performance coefficient finally obtained is shown in Table 1.

[0186] Table 1 Results of capillary performance coefficient K / Reff of various embodiments and comparative examples

[0187]

[0188] It can be seen from Table 1 that compared with Comparative Example 1, the capillary performance coefficients of each embodiment are all above 5.50×10 -6 m or more, which shows that the preparation method of a porous suction filter material provided in the embodiment of the present application, the liquid absorbent core product prepared by the preparation method has a finer pore structure. In addition, the embodiment is compared with the comparative example 5. Although the capillary performance coefficient of the comparative example 5 is similar to that of the embodiment, the comparative example 5 uses more water vapor, resulting in an increase in the cost of the overall method; and the embodiment is compared with the comparative example 9. Although the capillary performance coefficient of the comparative example 9 is similar to that of the embodiment, the comparative example 9 uses a higher dissolution molding temperature, which makes the energy consumption cost of the overall method larger.

[0189] In summary, the present invention provides a method for preparing a porous filter material. The method uses two different mixed powders, fully combines the solubility of magnesium-based alloy powders and advanced additive manufacturing technology, and successfully prepares a liquid absorbent core product with fine pore structure and uniform arrangement. The capillary performance coefficient of the liquid absorbent core product is 5.50×10 -6 m or more, it can meet the heat dissipation requirements of high-power and miniaturized electronic chips.

[0190] In addition, the embodiment of the present application provides a porous suction filter material, which has broad application prospects and potential practical value in many fields, such as aerospace, electronic equipment heat dissipation, chemical filtration, etc., and is particularly suitable for the field of heat dissipation equipment for high-power and miniaturized electronic chips.

[0191] In addition, a flat heat pipe provided in an embodiment of the present application has excellent thermal conductivity based on the above-mentioned porous filter material with good capillary performance coefficient, and can be widely used in aviation weather, electronic equipment, electric vehicles and other fields.

[0192] The above is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. It will be apparent to those skilled in the art that various modifications to these embodiments are possible, and the general principles defined in the present application can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown in the present application, but will conform to the widest range consistent with the principles and novel features applied for by the present application.

Claims

1. A method for preparing a porous suction filter material, characterized in that: The preparation method comprises: Mixing magnesium-based alloy powder, part of graphene and part of aluminum alloy powder to obtain a first mixed powder; Mixing the remaining aluminum alloy powder and the remaining graphene to obtain a second mixed powder; Performing preliminary additive manufacturing on the second mixed powder to obtain a substrate layer; According to the preset liquid wick structure, the first mixed powder and the second mixed powder are used to perform gradient additive manufacturing on the surface of the substrate layer to obtain a liquid wick substrate with a multi-layer overlapping structure; wherein the gradient additive manufacturing includes a first-level additive manufacturing and a second-level additive manufacturing, the first-level additive manufacturing is used for molding the first mixed powder, and the second-level additive manufacturing is used for molding the second mixed powder; The liquid wick substrate is dissolved and formed in a water vapor environment, and then vacuum dried to obtain a porous filter material; The laser power of the first-level additive manufacturing is 100W-150W, the scanning speed of the first-level additive manufacturing is 800mm / s-1200mm / s, the scanning pitch of the first-level additive manufacturing is 80μm-120μm, the layer thickness of the first-level additive manufacturing is 15μm-25μm, and the spot diameter of the first-level additive manufacturing is 5μm-10μm; and / or The laser power of the second-level additive manufacturing is 180W-200W, the scanning speed of the second-level additive manufacturing is 1400mm / s-1600mm / s, the scanning pitch of the second-level additive manufacturing is 150μm-180μm, the layer thickness of the second-level additive manufacturing is 55μm-65μm, and the spot diameter of the second-level additive manufacturing is 25μm-35μm; and / or The laser power of the preliminary additive manufacturing is 180W to 200W, the scanning speed of the preliminary additive manufacturing is 1400mm / s to 1600mm / s, the scanning pitch of the preliminary additive manufacturing is 150μm to 180μm, the layer thickness of the preliminary additive manufacturing is 55μm to 65μm, and the spot diameter of the preliminary additive manufacturing is 25μm to 35μm; The mass ratio of the magnesium-based alloy powder, part of the graphene and part of the aluminum alloy powder is (20-30): (10-20): 100; and / or The mass ratio of the remaining aluminum alloy powder to the remaining graphene is 100:(5-15); The temperature of the dissolution molding is 85° C. to 95° C., and the time of the dissolution molding is 20 min to 40 min.

2. The preparation method according to claim 1, characterized in that: The method of using the first mixed powder and the second mixed powder to perform gradient additive manufacturing on the surface of the substrate layer according to the preset liquid absorbent core structure to obtain a liquid absorbent core substrate with a multi-layer overlapping structure includes the following steps: According to the preset liquid wick structure, the first mixed powder is laid on the surface of the substrate layer to perform the first-level additive manufacturing to obtain a first functional layer; Laying the second mixed powder on the surface of the first functional layer to perform the second-level additive manufacturing to obtain a second functional layer; The first-level additive manufacturing and the second-level additive manufacturing processes are repeated to form a plurality of the first functional layers and a plurality of the second functional layers on the surface of the substrate layer, and the second functional layer is located at the outermost layer, so as to obtain a liquid-absorbing core substrate with a multi-layer overlapping structure.

3. The preparation method according to claim 1 or 2, characterized in that: The particle size of the magnesium-based alloy powder is 5 μm to 10 μm, the particle size of the graphene is 15 μm to 30 μm, and the particle size of the aluminum alloy powder is 25 μm to 50 μm.

4. The preparation method according to claim 1, characterized in that: The water vapor environment is a mixed gas of water vapor and an inert gas, and the volume ratio of the water vapor to the inert gas is (15-25): (85-75); and / or The flow rate of the mixed gas is 100 mL / min to 150 mL / min.

5. The preparation method according to claim 1, characterized in that: The preset liquid-absorbing core structure is a lattice structure having a plurality of pores of different shapes, wherein the different shapes include at least one of the following: triangle, quadrilateral, pentagon and hexagon.

6. A porous suction filter material, characterized in that: The porous suction filter material is prepared by the preparation method according to any one of claims 1 to 5.

7. A flat heat pipe, characterized in that: The flat plate heat pipe comprises the porous suction filter material according to claim 6 or comprises the porous suction filter material prepared by the preparation method according to any one of claims 1 to 5.

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