A method for integrally preparing a capillary core of a uniform temperature plate and a shell

Abstract

The application discloses a kind of even temperature plate capillary core and shell integrated preparation method, capillary core and shell are prepared by hot-pressing diffusion combination method formation;Capillary core is prepared by one or more layers of composite wire mesh, and the composite wire mesh is formed by 1-5 layers of metal wire mesh of the same material;All metal wire mesh is laminated according to a certain order to form composite wire mesh, the thickness of composite wire mesh is 0.2-1mm, aperture is 30-150 μm, porosity is 30-60%;The melting point of shell and composite wire mesh is less than 100℃, and the ratio of thermal expansion coefficient is 0.9-1.1.The method can complete the lamination of multiple metal wire mesh and the combination of capillary core and shell at one time by hot-pressing diffusion combination method, the method is simple, and the combination effect of the prepared capillary core and shell is good, which does not affect the porous characteristics of capillary core;Capillary core and shell are formed at one time, and the size matching is good;Directly formed by mold, the flatness of shell is high, and the deformation caused by the welding process of capillary core and shell is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of heat management, in particular to a method for integrally preparing a capillary wick and a shell of a vapor chamber. BACKGROUND

[0002] With the development of electronic devices towards miniaturization, functionalization, integration and high frequency, the increase of heat density has become a serious challenge to the development of electronic devices, which limits the application of electronic components. Heat pipes and vapor chambers are considered to be effective electronic heat management materials due to their high thermal conductivity, high stability and high reliability, and have been widely used in various electronic devices, aerospace and military fields.

[0003] The existing preparation technology of the vapor chamber with the silk screen as the capillary wick generally sinter-composites multiple layers of silk screens first, then fixes the silk screen capillary wick and the punched shell through spot welding or brazing, and then performs subsequent steps. Using this preparation technology, there are some problems in the spot welding and brazing links. On the one hand, the combination strength of the capillary wick and the shell is poor, which may cause the capillary wick to fall off, and on the other hand, spot welding only forms contact at some points of the capillary wick and the shell, and there are gaps at the un-welded parts, which are easy to form a vapor film during the heat transfer process, seriously affecting the heat transfer effect. When using brazing to fix, the molten filler will enter the pores of the silk screen through capillary action during the brazing heating process, blocking some mesh holes, thereby affecting the heat transfer performance. SUMMARY

[0004] The present application provides a method for integrally preparing a capillary wick and a shell of a vapor chamber, which aims to solve the above problems existing in the background art.

[0005] The technical solution provided by the present application is as follows:

[0006] A method for integrally preparing a capillary wick and a shell of a vapor chamber is prepared by using a hot-pressing diffusion combination method for the capillary wick and the shell;

[0007] The capillary wick is prepared by one or more layers of composite metal wire screens, and the composite metal wire screen is formed by 1-5 layers of metal wire screens of the same material;

[0008] The metal wire screens are laid and compounded in a certain order to form the composite metal wire screen, the thickness of the composite metal wire screen is 0.2-1mm, the pore size is 30-150μm, and the porosity is 30-60%;

[0009] The melting point difference between the shell and the composite metal wire screen is less than 100℃, and the ratio of the thermal expansion coefficients is 0.9-1.1.

[0010] Further, when the capillary wick and the shell are prepared, the shell is laid on the bottom layer, and the wire mesh is laid on the shell from bottom to top according to the order of average aperture from small to large.

[0011] Further, the mold for preparing the uniform temperature plate is provided with grooves matching the size of the required uniform temperature plate, and the mold comprises one upper mold and one lower mold, and 10-30 intermediate molds, the upper mold is provided with a protrusion, the lower mold is provided with a groove, the upper side and the lower side of the intermediate mold are respectively provided with the groove and the protrusion, the taper of the groove and the protrusion is >1°, the flatness of the assembly surface of the mold is <0.3 mm, the depth of the groove is greater than the height of the protrusion, the height difference is the total thickness of the shell and the capillary wick after compounding-0.1-0.5 mm, and the gap between the groove and the protrusion is the total thickness of the shell and the capillary wick after compounding-0.1-0.5 mm.

[0012] Further, the material of the wire mesh and the shell comprises stainless steel, copper, aluminum, nickel-based alloy, aluminum alloy, and copper alloy.

[0013] Further, the sintering environment of the uniform temperature plate is vacuum, hydrogen, nitrogen or argon, and the sintering temperature is 600-1300°C.

[0014] Further, the integrated preparation method of the capillary wick and the shell of the uniform temperature plate comprises the following steps:

[0015] S1, all the wire meshes and the shell are cut into the required size, and the wire meshes and the plate material are cut into the same size, and the wire meshes and the plate material are cleaned by using a metal cleaning agent to remove the surface oxide scale and oil stains;

[0016] S2, all the wire meshes are laid from bottom to top according to the order of aperture from small to large, the plate material is placed on the lowest layer, the laid plate material and the wire meshes are placed between the molds, and the processing materials and the molds are alternately stacked according to the requirements, and the processing materials are the plate material and the wire meshes;

[0017] S3, the loaded processing materials are loaded into the furnace, and the temperature is raised to 600-1300°C under the atmosphere of vacuum, hydrogen, nitrogen or argon, and the temperature is kept for 0.5-4 h, after the temperature keeping is completed, the furnace is cooled to 45°C, and the uniform temperature plate can be obtained after the furnace is discharged.

[0018] Further, during the sintering process of loading the processing materials into the furnace in step S3, pressure needs to be added, and the specific operation of adding pressure is as follows:

[0019] 0.5T of preliminary pressure is added before the temperature is raised, with the increase of the temperature, the metal begins to deform plastically, and then the pressure is gradually increased to 1-5T.

[0020] Compared with the prior art, the present application has the following advantages:

[0021] The present application provides a method for integrally preparing a capillary wick and a shell of a vapor chamber. The method can complete the compounding of multiple layers of metal wire meshes and the combination of the capillary wick and the shell at one time through a hot-pressing diffusion combination method. The method is simple in process, and the combination of the capillary wick and the shell prepared by the method is good, and the porous characteristics of the capillary wick are not affected. The capillary wick and the shell are formed at one time, and the size matching is good. The shell is directly formed through a mold, and the flatness of the shell is high, and the deformation caused by the welding process of the capillary wick and the shell is avoided. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The figure shows a furnace loading diagram for the plate and mold used for the capillary wick and the shell in the embodiments of the present application.

[0023] The reference signs are as follows:

[0024] 1 - upper mold, 2 - intermediate mold, 3 - lower mold, 4 - metal wire mesh, 5 - shell, 6 - groove, 7 - protrusion. DETAILED DESCRIPTION

[0025] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application in conjunction with the drawings in the embodiments of the present application. Obviously, the embodiments described below are only a part of the embodiments of the present application, rather than all the embodiments of the present application. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0026] Therefore, the detailed description of the embodiments of the present application provided below in conjunction with the drawings is intended to represent only selected embodiments of the present application, and not to limit the scope of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of the present application.

[0027] In the description of the embodiments of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms “arrange”, “mount”, “connect”, “connect” should be understood broadly, for example, can be fixedly connected, or can be detachably connected, or integrally connected; can be mechanically connected, or electrically connected or can communicate with each other; can be directly connected, or indirectly connected through an intermediate medium, or the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0028] Reference Figure 1The application provides a method for integrally preparing a capillary wick and a shell of a vapor chamber.

[0029] The capillary wick is prepared from one or more layers of a composite metal wire mesh, which is formed by 1-5 layers of metal wire meshes 4 of the same material.

[0030] All the metal wire meshes 4 are laid and combined in a certain order to form the composite metal wire mesh, which has a thickness of 0.2-1 mm, a pore size of 30-150 μm and a porosity of 30-60%. Within the range of the pore size and the porosity, the capillary wick can have sufficient capillary force and fluid medium transmission channels.

[0031] The melting point of the shell 5 and the composite metal wire mesh differs by less than 100 ℃, and the ratio of the thermal expansion coefficients is 0.9-1.1.

[0032] The shell 5 and the composite metal wire mesh can be of the same material, or other metal materials that have a melting point difference of less than 100 ℃ and a ratio of the thermal expansion coefficients of 0.9-1.1 and do not react with each other. The small melting point difference can ensure that the two materials can realize solid-phase sintering at the same sintering temperature, avoiding that one of the materials forms a liquid phase and blocks the mesh holes. The small difference in the thermal expansion coefficients can avoid that the capillary wick falls off due to the different shrinkage rates of the capillary wick and the shell during the cooling process.

[0033] Optionally, the mold for preparing the vapor chamber is made of a material that does not react with the metal wire mesh and the shell plate, and the mold is provided with grooves matching the size of the vapor chamber. The mold includes one upper mold 1 and one lower mold 3, and 10-30 middle molds 2. The upper mold 1 is provided with a protrusion 7, the lower mold 3 is provided with a groove 6, and the upper side and the lower side of the middle mold 2 are respectively provided with the groove 6 and the protrusion 7. The taper of the groove 6 and the protrusion 7 is >1°, the flatness of the assembly surface of the mold is <0.3 mm, the depth of the groove 6 is greater than the height of the protrusion 7, the height difference is the total thickness of the shell and the capillary wick after combination-0.1-0.5 mm, and the gap between the groove 6 and the protrusion 7 is the total thickness of the shell and the capillary wick after combination-0.1-0.5 mm.

[0034] Optionally, the material of the metal wire mesh 4 and the shell 5 includes stainless steel, copper, aluminum, nickel-based alloy, aluminum alloy and copper alloy.

[0035] Optionally, the sintering environment during the integrally preparing the capillary wick and the shell of the vapor chamber is vacuum, hydrogen, nitrogen or argon, and the sintering temperature is 600-1300 ℃.

[0036] The method for integrally preparing the capillary wick and the shell of the vapor chamber provided by the application includes the following steps:

[0037] S1, cut all the metal wire mesh 4, shell 5 with sheet material into the required size, and cut the metal wire mesh 4 and sheet material into the same size, use metal cleaner to clean the metal wire mesh 4 and sheet material, remove the surface oxide scale and oil stains.

[0038] S2, lay all the metal wire mesh 4 from bottom to top according to the pore size from small to large, then place the sheet material on the lowest layer, place the laid sheet material and metal wire mesh 4 between the mold, according to the need, alternately stack the processing materials and the mold, the processing materials are metal wire mesh 4 and sheet material.

[0039] S3, load the loaded processing materials into the furnace, heat to 600-1300℃ in vacuum, hydrogen, nitrogen or argon atmosphere, and keep for 0.5-4h, after keeping, cool to 45℃ with the furnace, and get the uniform temperature plate after taking out of the furnace.

[0040] Optionally, in step S3, the processing materials loaded into the furnace also need to be sintered under pressure, and the specific operation of pressure is as follows:

[0041] Preliminary pressure of 0.5T is applied before heating, as the temperature rises, the metal begins to deform plastically, and then the pressure is gradually increased to 1-5T.

[0042] It should be noted that in step S3, the pressure is applied according to the deformation temperature of different materials to control the porosity of the capillary core and ensure the bonding strength of the capillary core and the shell 5.

[0043] Example 1

[0044] The embodiment provides a combination method of stainless steel uniform temperature plate capillary core and shell, wherein the capillary core is prepared by four layers of 316L stainless steel wire mesh, and the shell 5 is prepared by 316L stainless steel metal sheet. The method combines four layers of 316L stainless steel wire mesh by hot pressing diffusion bonding, and combines the composite wire mesh with the shell 5.

[0045] The hot pressing diffusion bonding method is to place the shell 5 of 316L stainless steel metal sheet and four layers of 316L stainless steel wire mesh in a certain order between the upper mold 1 and the lower mold 3, pressurize and heat to a certain temperature, and keep for a certain time, so that the multi-layer metal wire mesh 4 is combined, and the composite wire mesh is combined with the shell 5.

[0046] The four layers of 316L stainless steel wire mesh have an average pore size of 10μm, 50μm, 100μm and 150μm respectively. The thickness of the four-layer stainless steel composite wire mesh after hot pressing diffusion bonding is 0.5mm, the average pore size is 25μm, and the porosity is 35%.

[0047] The sintering environment is a hydrogen atmosphere, the temperature is 1300 DEG C, and the holding time is 2h.

[0048] The mold is a graphite mold with grooves and protrusions, one upper mold 1 and one lower mold 3, 15 middle molds 2, the depth of the groove 6 in the mold is 5mm, the height of the protrusion 7 is 4.6mm, the taper of the groove 6 and the protrusion 7 is 2 DEG, the flatness of the mold assembly surface is 0.2mm, and the upper and lower mold assembly gap is 0.4mm.

[0049] As shown in Figure 1 The stainless steel heat sink capillary core and shell 5 combination method provided by the embodiment is prepared by the following process:

[0050] S1, cut the four layers of 316L stainless steel wire mesh and the shell 5 of 316L stainless steel metal sheet into 400*800mm, and clean the 316L stainless steel wire mesh and the shell 5 with a metal cleaning agent to remove surface oxidation scale, oil stains and the like.

[0051] S2, lay the multiple layers of 316L stainless steel wire mesh and the shell 5 in the order of the shell 5, 10um stainless steel wire mesh, 50um stainless steel wire mesh, 100um stainless steel wire mesh and 150um stainless steel wire mesh from bottom to top. Place the laid shell 5 and 316L stainless steel wire mesh between the molds, and lay 16 layers in total.

[0052] S3, load the prepared material into the furnace, heat to 1300 DEG C under a hydrogen atmosphere, and hold for 2h. Before heating, preliminarily pressurize to 0.5T, pressurize to 1T at 850 DEG C, and pressurize to 3T at 1050 DEG C. After completing the holding procedure, cool to 45 DEG C with the furnace, depressurize, and take out the furnace to obtain a 316L heat sink capillary core and shell composite.

[0053] In this embodiment, the capillary core is composed of four layers of 316L stainless steel wire mesh, the thickness of the capillary core is 0.5mm, the average pore size is 25um, and the porosity is 35%. Within this pore size and porosity range, the capillary core can have sufficient capillary force and fluid medium transmission channels.

[0054] In summary, the present application provides a heat sink capillary core and shell integrated preparation method, which can complete the compounding of the multiple layers of metal wire mesh 4 and the combination of the capillary core and the shell 5 at one time by the hot pressing diffusion combination method. The method is simple in process, has good combination effect of the prepared capillary core and the shell 5, and will not affect the porous characteristics of the capillary core. The capillary core and the shell 5 are formed at one time, and the size matching is good. The shell 5 is directly formed by a mold, the flatness of the shell 5 is high, and the problems such as deformation caused by the welding process of the capillary core and the shell 5 are avoided.

[0055] The above merely provides the most specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any change or replacement within the technical scope disclosed by the present application should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for preparing an integrated heat spreader capillary core and shell, characterized in that, It is prepared by hot-pressing diffusion bonding of capillary core and shell; The capillary core is made of one or more layers of composite metal wire mesh, wherein the composite metal wire mesh is formed by combining 1 to 5 layers of metal wire mesh of the same material. The composite metal wire mesh is formed by laying down layers in a certain order. The thickness of the composite metal wire mesh is 0.2~1mm, the pore size is 30~150μm, and the porosity is 30~60%. The melting point difference between the shell and the composite metal wire mesh is less than 100°C, and the ratio of their coefficients of thermal expansion is 0.9 to 1.

1. The mold for preparing the heat spreader is provided with a groove matching the required size of the heat spreader. The mold includes one upper mold and one lower mold, and 10 to 30 intermediate molds. The upper mold is provided with a protrusion, the lower mold is provided with a groove, and the upper and lower sides of the intermediate molds are respectively provided with the groove and the protrusion. The taper of the groove and the protrusion is >1°, the flatness of the mold assembly surface is <0.3mm, the depth of the groove is greater than the height of the protrusion, and the height difference is -0.1 to -0.5mm of the total thickness of the shell and the capillary core after they are combined. The gap between the groove and the protrusion is -0.1 to -0.5mm of the total thickness of the shell and the capillary core after they are combined. The method includes the following steps: S1. Cut all the metal wire mesh and shell into the required size using sheet metal, and cut the metal wire mesh and the sheet metal into the same size. Clean the metal wire mesh and the sheet metal with a metal cleaning agent to remove surface oxide scale and oil stains. S2. Lay the metal wire mesh from bottom to top according to the increasing aperture size, then place the plate at the bottom layer, and place the laid plate and the metal wire mesh between the molds. As needed, alternately stack the processing materials and the molds. The processing materials are the plate and the metal wire mesh. S3. Load the prepared processing material into the furnace, and heat it to 600~1300℃ in a vacuum, hydrogen, nitrogen or argon atmosphere, hold it at that temperature for 0.5~4h. After holding, cool it down to 45℃ with the furnace, and the integrated capillary core and shell can be obtained by removing it from the furnace. During the sintering process of the processed material in the furnace, pressure is also required. The specific operation of pressure application is as follows: before heating, apply an initial pressure of 0.5T. As the temperature rises, the metal begins to undergo plastic deformation, and then gradually increase the pressure to 1~5T.

2. The method for preparing an integrated heat exchanger capillary core and shell according to claim 1, characterized in that: When preparing the heat exchanger, the capillary core and the shell are arranged as follows: the shell is laid on the bottom layer, and the metal wire mesh is laid on the shell from bottom to top in order of increasing average pore size.

3. The method for preparing an integrated heat exchanger capillary core and shell according to claim 1, characterized in that: The materials of the metal wire mesh and the shell include stainless steel, copper, aluminum, nickel-based alloys, aluminum alloys, and copper alloys.

4. The method for preparing an integrated heat exchanger capillary core and shell according to claim 1, characterized in that: The sintering environment for the capillary core and the shell is vacuum, hydrogen, nitrogen or argon, and the sintering temperature is 600~1300℃.

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