Vapor chamber and preparation method thereof

Abstract

The invention relates to the technical field of heat dissipation devices, in particular to a preparation method of a vapor chamber and the vapor chamber prepared by the preparation method. The preparation method sequentially comprises the following steps that firstly, a shell powder raw material is rolled, and a compact shell green body is formed; 2, arranging a wick powder raw material on the compact shell green body, forming the wick powder raw material through a pressing process, and preliminarily combining the wick powder raw material with the compact shell green body to form a core-shell integrated green body; and thirdly, the core-shell integrated green body is sintered, and the core-shell integrated piece is obtained. Through the combination of a powder rolling and sintering process, one-time sintering integrated forming of the wick and the shell structure is achieved, the complex working procedure of secondary sintering combination and the defects of instability of a powder laying process and powder particle flowing are avoided, the uniformity and controllability of the thickness of the wick can be ensured, and the production efficiency is improved. And meanwhile, firm combination of the wick and the shell structure can be ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of heat dissipation devices, and in particular to a method for preparing a vapor chamber and a vapor chamber. Background Art

[0002] As the power density of electronic devices continues to increase, higher requirements are placed on heat dissipation technology, especially in the fields of high-performance computing, big data processing and mobile communications, the heat dissipation problem of electronic devices is particularly prominent. Traditional heat dissipation technologies, such as fan heat dissipation and heat pipe heat dissipation, have been unable to meet the growing demand for heat dissipation. The heat spreader is a heat dissipation device that uses the absorption and release of latent heat during the phase change process of the working fluid to achieve efficient heat transfer. It has gradually become an ideal heat dissipation device for the current temperature control system. The wick is a key component for the heat spreader to achieve efficient heat transfer. It is responsible for transferring heat from the heat source to the coolant. The structure and preparation process of the wick are the key factors restricting the performance improvement of the heat spreader.

[0003] In the prior art, the wick is mostly prepared by sintering powder or wire mesh. Usually, a heat spreader with a powder sintered porous wick cannot sinter out a sample in one go, but needs to sinter out the porous wick first, then sinter the wick and the shell into a whole, and finally sinter the upper and lower shells together to form a sample. This sintering process has the following problems: (1) The powder spreading process has the disadvantages of instability and powder particle flow, resulting in uneven thickness of the liquid absorbent core; (2) Two sinterings are required to form the overall structure of the liquid absorbent core shell, which is cumbersome and energy-intensive, and the secondary sintering treatment of the porous material has a certain impact on the stability of its porous properties; (3) The conventional secondary sintered porous liquid absorbent core and shell are usually unconstrained sintering, and the sintering process has problems such as the tightness of the bonding between the porous layer and the shell and the weak metallurgical bonding strength, which will lead to the porous liquid absorbent core and the shell being unreliable, the liquid absorbent core peeling off, and residual air inside, thereby affecting the mechanical strength of the heat spreader and causing the problem of greatly reduced heat transfer efficiency due to the increase in thermal resistance of the evaporation end of the heat spreader.

[0004] In addition, in the horizontal heat spreader device, there is a problem that the working fluid at the far end of the condensation end does not flow back in time or cannot flow back. The failure of the working fluid at the condensation end to quickly flow back to the evaporation zone will cause drying, resulting in a decrease in the heat transfer capacity of the heat spreader. Conventional non-gradient porosity wicks have the mutually exclusive characteristics of capillary force and permeability, which makes it impossible for the working fluid to be pumped back from the cold end to the hot end, or even if it can be pumped back to the hot end, it cannot penetrate to the contact position between the wick and the shell, and it is impossible to absorb heat from the hot end, thereby affecting the heat dissipation performance of the device. Conventional gradient porosity wicks have a gradient porosity structure of an upper and lower gradient change type or a single radial gradient change type. Usually, an upper layer of powder and a lower layer of silk screen are used, or the upper and lower layers are powders or silk screens with different pore structures. Since the change in gradient porosity is uniform and gradual, it is essentially similar to a non-gradient porosity structure and cannot effectively promote the timely return of the working fluid. Summary of the invention

[0005] In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is to provide a heat spreader and a preparation method thereof, which can realize one-time sintering of the liquid absorbent core and the shell structure into an integral body.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] The present invention provides a method for preparing a heat spreader, which comprises the following steps in sequence: step 1, rolling a shell powder raw material to form a dense shell green body; step 2, arranging a liquid wick powder raw material on the dense shell green body, forming the liquid wick powder raw material through a pressing process and preliminarily combining it with the dense shell green body to form a core-shell integrated green body; step 3, sintering the core-shell integrated green body to obtain a core-shell integrated part.

[0008] Preferably, in step one, two dense shell green sheets are formed, and a groove is provided on at least one of the dense shell green sheets; in step two, at least one core-shell integrated green sheet is formed using the dense shell green sheet provided with the groove.

[0009] Preferably, in step three, a core-shell integrated green body is used as the lower shell, and another core-shell integrated green body or a dense shell green body with a groove or a dense shell green body without a groove is used as the upper shell. The upper shell and the lower shell are placed relative to each other to form a heat spreader assembly green body. The heat spreader assembly green body is sintered and packaged with furnace welding to obtain a heat spreader sample.

[0010] Preferably, in step three, a core-shell integrated green body is sintered to obtain a core-shell integrated part as a lower shell, and another core-shell integrated green body or a dense shell green body with a groove or a dense shell green body without a groove is sintered to obtain a core-shell integrated part or a shell part with a groove or a shell part without a groove as an upper shell, and the upper shell and the lower shell are placed relative to each other, combined, welded and packaged to obtain a heat spreader sample.

[0011] Preferably, in step 2, the pressing process is rolling or cold isostatic pressing.

[0012] Preferably, in step 2, support columns are arranged on the core-shell integrated green body.

[0013] Preferably, in step 2, the liquid wick powder raw material includes metal powder and pore-forming agent, and the metal powder and the shell powder raw material have the same or different components.

[0014] Preferably, there are multiple types of liquid absorbent core powder raw materials, each of which has different metal powder particle sizes and pore-forming agent contents. The multiple liquid absorbent core powder raw materials are alternately arranged laterally on the dense shell green body, so that the liquid absorbent core of the core-shell integrated component sintered in step three has a laterally alternating gradient porosity.

[0015] The present invention also provides a vapor chamber, which is prepared by the vapor chamber preparation method as described above.

[0016] Preferably, the liquid absorbent core and the shell structure are integrally formed, and the liquid absorbent core has a transversely alternating gradient porosity that changes alternately in the transverse direction.

[0017] Compared with the prior art, the present invention has significant improvements:

[0018] The present invention forms a dense shell green body through powder rolling, and forms the liquid absorbent core powder raw material arranged on the dense shell green body through a pressing process, and has a preliminary combination with the dense shell green body to form a core-shell integrated green body integral part. Therefore, the core-shell integrated green body has a certain structural strength and bonding strength, and will not loosen and lose powder. Then the core-shell integrated green body is sintered, that is, the liquid absorbent core and the shell structure are sintered and formed into one piece in one time, avoiding the complicated process of powder-laying sintering liquid absorbent core and secondary sintering and combining the liquid absorbent core shell in the manufacturing process of the powder sintering liquid absorbent core heat spreader of the prior art, and can avoid the instability of the powder sintering powder-laying process of the prior art and the disadvantages of powder particle flow, can ensure the uniformity and controllability of the liquid absorbent core thickness of the sintered core-shell integrated part, improve production efficiency, and at the same time ensure that the liquid absorbent core and the shell structure are firmly combined, and the two will not be easily separated, and the reduction of contact thermal resistance can greatly improve the heat transfer efficiency, effectively overcoming the problems of unreliable sintering and large thermal resistance of the liquid absorbent core and the shell. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the split structure of the heat spreader according to an embodiment of the present invention.

[0020] Figure 2 1 is a schematic longitudinal section of the lower shell of the heat spreader according to an embodiment of the present invention.

[0021] The reference numerals are described as follows:

[0022] 1 Lower housing

[0023] 2 Upper housing

[0024] 10 Core-shell integrated parts

[0025] 101 wick

[0026] 101a First porous wick structure

[0027] 101b Second porous wick structure

[0028] 102 Shell structure

[0029] 20 Support columns

[0030] 30 Shell parts DETAILED DESCRIPTION

[0031] The specific embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. These embodiments are only used to illustrate the present invention, but not to limit the present invention.

[0032] In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0033] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0034] Furthermore, in the description of the present invention, unless otherwise specified, “plurality” means two or more.

[0035] like Figure 1 and Figure 2 The figure shows an embodiment of the method for preparing the heat spreader provided by the present invention.

[0036] The method for preparing the vapor chamber of this embodiment includes the following steps in sequence.

[0037] Step 1: Roll the shell powder raw material to form a dense shell green body. Through powder rolling, the shell powder raw material is formed into a dense shell green body with a desired thickness as a heat spreader shell material. The dense shell green body can be obtained from the shell powder raw material by one rolling or two rolling. The density of the dense shell green body is not less than 98%. The high density makes the dense shell green body have a certain strength and will not loosen or fall off.

[0038] In step 1, the shell powder raw material is metal powder, and the composition of the shell powder raw material is determined according to the shell material requirements of the heat spreader to be prepared, for example, it can be copper powder, aluminum powder, or nickel powder. The particle size distribution, sphericity, and purity of the shell powder raw material will affect the overall performance of the final heat spreader product, and can be selected and designed according to the performance requirements of the heat spreader to be prepared.

[0039] Preferably, in step 1, two dense shell green sheets are formed to serve as upper and lower shell materials of the heat spreader respectively. A groove is provided on at least one dense shell green sheet, and the groove can be formed by stamping or etching on the dense shell green sheet. The groove is used to form the internal cavity of the heat spreader and to prepare for arranging the wick powder raw material on the dense shell green sheet in the following step 2. Therefore, the groove is provided on the structural surface of the dense shell green sheet, which refers to a side surface of the dense shell green sheet used to form at least part of the cavity wall of the internal cavity of the heat spreader.

[0040] Step 2, arrange the liquid absorbent core powder raw material on the dense shell green body, and shape the liquid absorbent core powder raw material through the pressing process and preliminarily combine it with the dense shell green body to form a core-shell integrated green body. The liquid absorbent core powder raw material arranged on the dense shell green body can be shaped by the pressing pressure and preliminarily combined with the dense shell green body, thereby forming a core-shell integrated green body integral part, and the core-shell integrated green body has a certain structural strength and bonding strength, and will not loosen and fall off. Therefore, when the core-shell integrated green body is sintered in the following step three, the instability of the powder sintering and powdering process of the prior art and the disadvantages of the flow of powder particles are avoided, and the uniformity and controllability of the thickness of the liquid absorbent core 101 of the sintered core-shell integrated part 10 can be ensured, and the production efficiency can be improved. At the same time, it can also ensure that the liquid absorbent core 101 of the core-shell integrated part 10 is firmly combined with the shell structure 102, and the two will not be easily separated, and the decrease in contact thermal resistance can greatly improve the heat transfer efficiency, effectively overcoming the problems of unreliable sintering of the liquid absorbent core and the shell, and large thermal resistance. By controlling parameters such as pressure, speed, and time during the pressing process, the density of the core-shell green body can be ensured to be uniform and free of defects.

[0041] In step 2, the liquid wick powder raw material includes metal powder and pore-forming agent. The composition of the metal powder of the liquid wick powder raw material is determined according to the physical property requirements of the liquid wick of the heat spreader to be prepared, for example, suitable copper powder or aluminum powder or nickel powder can be selected. The particle size distribution, sphericity and purity of the metal powder of the liquid wick powder raw material will affect the performance of the final heat spreader product, and can be selected and designed according to the performance requirements of the heat spreader to be prepared. The composition of the metal powder of the liquid wick powder raw material and the shell powder raw material is preferably the same, so that the shell material and the liquid wick material are the same, which is conducive to the sintering and bonding of the liquid wick powder raw material and the dense shell green body in the following step 3. The metal powder of the liquid absorbent core powder raw material and the shell powder raw material may also have different compositions, so that the shell material and the liquid absorbent core material are different. At this time, in order to facilitate the sintering and combining of the liquid absorbent core powder raw material and the dense shell green body in the following step three, a component that can adjust its sintering performance can be added to the metal powder or shell powder raw material of the liquid absorbent core powder raw material, so that the two different powders are suitable for the same sintering process, thereby facilitating the sintering and combining of the liquid absorbent core powder raw material and the dense shell green body in the following step three. The pore-forming agent is used to decompose into gas and escape during the sintering process of the liquid absorbent core powder raw material in the following step three to form a porous liquid absorbent core structure with a certain porosity (the porosity is preferably 30%-60%). The pore-forming agent can be selected from conventional pore-forming agents, such as PMMA, ammonium bicarbonate, etc. The pore-forming agent is mixed with the metal powder in proportion to form the liquid absorbent core powder raw material. The particle size of the pore-forming agent should match the particle size of the metal powder of the liquid absorbent core powder raw material. The particle size of the pore-forming agent determines the pore size of the porous liquid absorbent core structure to a certain extent. The content of the pore-forming agent and the particle size of the pore-forming agent determine the porosity of the porous liquid absorbent core structure to a certain extent. Therefore, by using liquid absorbent core powder raw materials with different metal powder particle sizes and pore-forming agent contents, porous liquid absorbent core structures with different porosities and pore sizes can be obtained. For example, coarse powder sintering can obtain a porous liquid absorbent core structure with high permeability and low capillary force, and fine powder sintering can obtain a porous liquid absorbent core structure with higher capillary force but low permeability.

[0042] Preferably, in step 2, a plurality of liquid absorbent core powder raw materials are provided, and the plurality of liquid absorbent core powder raw materials have different metal powder particle sizes and pore-forming agent contents, and the plurality of liquid absorbent core powder raw materials are alternately arranged laterally on the dense shell green body, so that the liquid absorbent core 101 of the core-shell integrated part 10 sintered in the following step 3 has a laterally alternating gradient porosity, such as Figure 1 and Figure 2In a preferred embodiment, a first porous wick structure 101a sintered from coarse powder with higher permeability and lower capillary force and a second porous wick structure 101b sintered from fine powder with higher capillary force and lower permeability are alternately arranged in the transverse direction. It should be noted that the "transverse direction" in this article refers to a direction parallel to the dense shell green body. Arranging the wick structure with a transversely alternating gradient porosity is equivalent to effectively placing "water storage points" (the first porous wick structure 101a with higher permeability and lower capillary force) and "water delivery points" (the second porous wick structure 101b with higher capillary force and lower permeability) at different locations inside the wick 101, thereby achieving "relay" reflux of the working fluid, effectively balancing the capillary force and permeability of the wick 101, and assisting the continuous reflux of the remote condensed working fluid through relay capillary suction and penetration, effectively improving the directional reflux capacity and heat transfer efficiency of the working fluid, thereby being able to adapt to the working fluid reflux and heat transfer requirements under different heat loads, and solving the problem of untimely or inability to reflux the working fluid in the prior art.

[0043] Preferably, the pressing process in step 2 is rolling or cold isostatic pressing. The pressure of rolling or cold isostatic pressing can shape the liquid wick powder raw material arranged on the dense shell green body and form a preliminary bond with the dense shell green body, thereby forming a core-shell integrated green body.

[0044] Preferably, in step 2, at least one core-shell integrated green body is formed using a dense shell green body with grooves, that is, a liquid absorbent wick powder raw material is arranged on at least one dense shell green body with grooves, and the liquid absorbent wick powder raw material is formed by rolling or cold isostatic pressing and preliminarily combined with the dense shell green body to form a core-shell integrated green body with grooves.

[0045] Among them, when the liquid absorbent core powder raw material is rolled, in order to facilitate the alternating arrangement of multiple different liquid absorbent core powder raw materials in the horizontal direction on the dense shell green body, different areas for arranging different liquid absorbent core powder raw materials can be divided by arranging grooves on the dense shell green body according to the requirements of the horizontal alternating gradient porosity of the liquid absorbent core 101 of the heat spreader to be prepared. Then, multiple liquid absorbent core powder raw materials can be arranged alternately in the horizontal direction on the dense shell green body according to the areas divided by the grooves on the dense shell green body. After all are arranged, one or two rollings are performed to form a core-shell integrated green body.

[0046] When the wick powder raw material is subjected to cold isostatic pressing, in order to facilitate the alternating arrangement of a variety of different wick powder raw materials in the transverse direction on the dense shell green body, a corresponding mold can be designed according to the transverse alternating gradient porosity requirements of the wick 101 of the heat spreader to be prepared, and the mold material is a special alloy that is resistant to high temperatures and has stable dimensions. The mold is divided into different areas for arranging different wick powder raw materials. The dense shell green body can be placed in the mold, and a variety of wick powder raw materials can be arranged alternately in the transverse direction on the dense shell green body according to the areas divided in the mold. After all are arranged, they are formed by cold isostatic pressing to form a core-shell integrated green body.

[0047] Preferably, in step 2, support columns 20 are arranged on the core-shell integrated green body. Support columns 20 are pre-prepared components. Support columns 20 are located in the internal cavity of the heat spreader in the heat spreader, and play the role of supporting the upper and lower shells of the heat spreader and improving the heat transfer efficiency. They are conventional components of the heat spreader. In this embodiment, support columns 20 are arranged on the core-shell integrated green body, and after the core-shell integrated green body is sintered in the following step 3, a core-shell integrated part 10 with support columns 20 is formed.

[0048] Step 3: Sinter the core-shell green body, so that the liquid absorbent core powder raw material and the dense shell green body are further sintered and combined on the basis of the preliminary combination. At the same time, the dense shell green body is sintered to form the shell structure 102, and the formed liquid absorbent core powder raw material is sintered to form the porous liquid absorbent core 101. The gas generated by the decomposition of the pore-forming agent is discharged through the exhaust channel, thereby obtaining the core-shell integrated part 10, that is, the liquid absorbent core 101 and the shell structure 102 are sintered and formed into one piece at a time. Since the liquid absorbent core 101 material and the shell structure 102 material have been combined into one piece by rolling and pressing before sintering, only one sintering is required to realize the simultaneous and integral formation of the liquid absorbent core 101 and the shell structure 102, thereby avoiding the complex process of the powder sintering liquid absorbent core and the secondary sintering and combining of the liquid absorbent core shell in the manufacturing process of the powder sintering liquid absorbent core soaking plate in the prior art. The sintering is carried out in a high-temperature sintering furnace. The sintering temperature, time, atmosphere and other parameters can be optimized according to the characteristics of the wick powder raw materials and the shell powder raw materials to obtain the best pore structure and mechanical properties.

[0049] In one embodiment, preferably, in step three, a core-shell integrated green body is used as the lower shell 1, and another core-shell integrated green body or a dense shell green body with a groove or a dense shell green body without a groove is used as the upper shell 2. The upper shell 2 and the lower shell 1 are placed relative to each other and combined in the style of a heat spreader to form a heat spreader assembly green body. At least one of the dense shell green bodies in the upper shell 2 and the lower shell 1 has a groove to facilitate the formation of an internal cavity structure of the heat spreader to facilitate the flow of steam. Preferably, a support column 20 is also arranged between the upper shell 2 and the lower shell 1, and the heat spreader assembly green body is formed by combining the upper shell 2, the lower shell 1 and the support column 20. The assembled heat spreader assembly green body is formed with an internal cavity and a liquid injection hole for filling the cavity with a working medium. The assembled heat spreader assembly green body is sintered and packaged with furnace welding to obtain a heat spreader sample, which is also a core-shell integrated part. During sintering, the fixture can be used to limit and fix the heat spreader assembly green body. During the sintering process, the gas generated by the decomposition of the pore-forming agent in the liquid wick powder raw material can escape through the injection hole. Thus, the heat spreader sample can be obtained by only one sintering and the device sealing can be achieved during the sintering process, and the one-time sintering integrated forming of the heat spreader sample is achieved, which greatly simplifies the preparation process of the heat spreader. The powder metallurgy near-net forming method can effectively reduce costs, improve the stability and reliability of batch products, significantly reduce manufacturing energy consumption, and achieve energy conservation and emission reduction. The welding process of the furnace welding package can be selected according to the material of the upper shell 2 and the lower shell 1. For example, when the upper shell 2 and the lower shell 1 are copper materials, diffusion welding is preferably used. During the sintering process, the edges of the upper shell 2 and the lower shell 1 can be diffused and welded at the same time to achieve packaging; when the upper shell 2 and the lower shell 1 are aluminum materials, brazing is preferably used. Before sintering, the brazing material is applied to the edges of the upper shell 2 and the lower shell 1. During the sintering process, the edges of the upper shell 2 and the lower shell 1 can be brazed at the same time to achieve packaging. The welding process parameters (such as temperature, time, atmosphere, etc.) in the furnace are optimized according to the material properties of the upper shell 2 and the lower shell 1.

[0050] In another embodiment, preferably, in step three, a core-shell integrated green body is sintered to obtain a core-shell integrated part 10 as the lower shell 1, and another core-shell integrated green body or a dense shell green body with a groove or a dense shell green body without a groove is sintered to obtain a core-shell integrated part 10 or a shell part 30 with a groove or a shell part 30 without a groove as the upper shell 2, and the upper shell 2 and the lower shell 1 are relatively placed, combined, welded and packaged to obtain a heat spreader sample. At least one of the dense shell green bodies of the upper shell 2 and the lower shell 1 has a groove, so as to form an internal cavity structure of the heat spreader to facilitate the flow of steam. One of the upper shell 2 and the lower shell 1 has a support column 20, so that the heat spreader sample formed after the upper shell 2 and the lower shell 1 are combined, welded and packaged has a support column 20 structure. The heat spreader sample formed after the upper shell 2 and the lower shell 1 are relatively placed, combined, welded and packaged forms an internal cavity and a liquid injection hole for filling the cavity with a working medium. The upper shell 2 and the lower shell 1 that are combined to form the heat spreader sample are both integral parts that are sintered once. The heat spreader sample can be obtained by directly welding and packaging the two without the need for multiple sintering and bonding processes. The welding process for welding and packaging the upper shell 2 and the lower shell 1 preferably uses laser welding or argon arc welding to ensure the sealing and stability of the overall structure. The welding process parameters (such as current, voltage, speed, etc.) are optimized according to the material properties of the upper shell 2 and the lower shell 1.

[0051] In step three, the heat spreader sample or the core-shell integrated part 10 or the shell part 30 with grooves or the shell part 30 without grooves formed after the first sintering can be subjected to necessary post-processing, such as machining, cleaning, etc., to ensure dimensional accuracy and surface quality.

[0052] In step three, after obtaining the soaking plate sample, the soaking plate sample needs to be filled with working fluid and sealed, specifically: welding the injection tube at the injection hole of the soaking plate sample, first select the appropriate working medium (such as water, acetone or thermal oil, etc.) according to the application requirements and the soaking plate material after helium mass spectrometry leak detection, and fill the selected working medium into the internal cavity of the soaking plate sample through the injection tube; then vacuum the internal cavity of the soaking plate sample through the injection tube to remove the air and impurities in the internal cavity; after the vacuum reaches the set value, the injection tube is sealed to ensure the sealing of the soaking plate sample, and then the soaking plate shell is heated to drive the remaining non-condensable gas in the cavity and the liquid wick to the upper end of the injection tube, and then the upper end of the injection tube and the non-condensable gas therein are removed and further sealed. Thus, a soaking plate product is obtained.

[0053] Based on the above-mentioned method for preparing a vapor chamber, an embodiment of the present invention further provides a vapor chamber. The vapor chamber of this embodiment is prepared by the above-mentioned method for preparing a vapor chamber.

[0054] The heat spreader of this embodiment includes an integrally formed absorbent core 101 and a shell structure 102, and the integrally formed absorbent core 101 and the shell structure 102 constitute a core-shell integrated part 10, and the core-shell integrated part 10 serves as the lower shell 1 and / or the upper shell 2. When the core-shell integrated part 10 is used as the lower shell 1, the upper shell 2 can be a core-shell integrated part 10 or a shell part 30 with a groove or a shell part 30 without a groove. At least one of the shell structures 102 of the upper shell 2 and the lower shell 1 has a groove (that is, the dense shell green body used for sintering to form the shell structure has a groove), so as to form an internal cavity structure of the heat spreader to facilitate the flow of steam. A support column 20 is arranged between the upper shell 2 and the lower shell 1.

[0055] The heat spreader of this embodiment can be obtained by combining the upper shell 2 and the lower shell 1 in a green form to form a heat spreader combined green body, sintering it, and welding and packaging it in a furnace, or it can be obtained by sintering the upper shell 2 and the lower shell 1 into one piece at a time, and then combining them and welding and packaging them.

[0056] Preferably, the wick 101 of the heat spreader of this embodiment has a lateral alternating gradient porosity that changes alternately in the lateral direction, which can be achieved by arranging a plurality of wick powder raw materials with different metal powder particle sizes and pore-forming agent contents alternately in the lateral direction on the dense shell green body during preparation.

[0057] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a vapor chamber, characterized in that: The following steps are included in sequence: Step 1: rolling the shell powder raw material to form a dense shell green body; Step 2: arranging a liquid absorbent core powder raw material on the dense shell green body, forming the liquid absorbent core powder raw material through a pressing process and preliminarily combining it with the dense shell green body to form a core-shell integrated green body; Step three: sintering the core-shell integrated green body to obtain a core-shell integrated part.

2. The method for preparing a vapor chamber according to claim 1, characterized in that: In the step 1, two dense shell green sheets are formed, and a groove is provided on at least one of the dense shell green sheets; in the step 2, at least one core-shell integrated green sheet is formed using the dense shell green sheet provided with the groove.

3. The method for preparing a vapor chamber according to claim 2, wherein: In the step three, one of the core-shell integrated green sheets is used as the lower shell, and another of the core-shell integrated green sheets or the dense shell green sheets with the groove or the dense shell green sheets without the groove is used as the upper shell. The upper shell and the lower shell are placed relative to each other and combined to form a heat spreader assembly green sheet. The heat spreader assembly green sheet is sintered and packaged with furnace welding to obtain a heat spreader sample.

4. The method for preparing a vapor chamber according to claim 2, characterized in that: In the step three, one of the core-shell integrated green sheets is sintered to obtain a core-shell integrated part as a lower shell, and another core-shell integrated green sheet or a dense shell green sheet provided with the groove or a dense shell green sheet without the groove is sintered to obtain a core-shell integrated part or a shell part with a groove or a shell part without a groove as an upper shell. The upper shell and the lower shell are placed relative to each other, combined, welded and packaged to obtain a heat spreader sample.

5. The method for preparing a vapor chamber according to claim 1, characterized in that: In the step 2, the pressing process is rolling or cold isostatic pressing.

6. The method for preparing a vapor chamber according to claim 1, characterized in that: In the step 2, support columns are arranged on the core-shell integrated green body.

7. The method for preparing a vapor chamber according to any one of claims 1 to 6, characterized in that: In the step 2, the liquid wick powder raw material includes metal powder and pore-forming agent, and the metal powder and the shell powder raw material have the same or different components.

8. The method for preparing a vapor chamber according to claim 7, characterized in that: In the step 2, the liquid absorbent core powder raw materials are provided with a plurality of types, and the plurality of liquid absorbent core powder raw materials have different metal powder particle sizes and pore-forming agent contents. The plurality of liquid absorbent core powder raw materials are alternately arranged laterally on the dense shell green body, so that the liquid absorbent core of the core-shell integrated component sintered in the step 3 has a laterally alternating gradient porosity.

9. A heat spreader, characterized in that: The heat spreader is prepared by the method for preparing the heat spreader as described in any one of claims 1 to 8.

10. The vapor chamber according to claim 9, characterized in that: The invention comprises an integrally formed liquid absorbent core and a shell structure, wherein the liquid absorbent core has a transversely alternating gradient porosity which changes alternately in the transverse direction.

Images