Stainless steel ultrathin vapor chamber and preparation method thereof

Abstract

The invention relates to a stainless steel vapor chamber and a preparation method thereof. The stainless steel vapor chamber comprises an upper shell plate, a condensing surface structure, a supporting column, a liquid absorbing core and a lower shell plate; the upper shell plate is a flat plate, the middle of the lower shell plate is sunken to form an inner cavity, the upper shell plate and the lower shell plate are attached to each other and connected in a sealed mode to form a vapor chamber cavity, a liquid injection opening is formed in the side edge of the lower shell plate, the liquid injection opening is communicated with the inner cavity, and a liquid working medium is injected through the liquid injection opening. The condensing surface is the inner surface of the upper shell plate, and a plurality of hydrophobic bud structures are arranged on the surface; the liquid absorbing core is a stainless steel fiber felt with a plurality of hydrophilic nano needle-shaped structures, and the stainless steel fiber felt is connected with the bottom surface of the inner cavity of the lower shell plate. On the premise that the overall structural strength, stability and reliability of a product are guaranteed, liquid-vapor-liquid circulation in the inner cavity of the vapor chamber is accelerated, and the overall heat conduction performance of the vapor chamber is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of thermal management of electronic components, and in particular relates to a stainless steel soaking plate and a preparation method thereof. Background Art

[0002] As a core component of the vapor chamber, the wick plays a crucial role in its performance. Two key factors influence vapor chamber performance: first, the ability of internal vapor chamber vapor to rapidly release heat and condense into a liquid working medium at the condensation surface; and second, the ability of the liquid working medium to rapidly flow back to the heat source through the wick structure, absorb heat, and transform into vapor, thereby achieving sustained, rapid, and cyclical heat transfer from liquid to vapor to liquid within the vapor chamber. This is specifically manifested in the super-hydrophilicity of the wick and the super-hydrophobicity of the condensation surface.

[0003] Currently, the primary materials used to manufacture vapor chambers are aluminum and copper alloys. However, for increasingly thinner vapor chambers or those requiring higher mechanical strength, copper-aluminum vapor chambers no longer meet the strength requirements. Furthermore, copper vapor chambers are susceptible to rust and dirt on their exterior surfaces. Stainless steel, a high-strength material, has a thermal conductivity of only 16 W / m∙K and a hydrophobic surface. Due to its inherent properties, stainless steel vapor chambers suffer from poor capillary properties and slow internal steam condensation, resulting in poor overall heat transfer performance. Summary of the Invention

[0004] The object of the present invention is to provide a stainless steel vapor chamber with good heat exchange performance and high mechanical strength and a preparation method thereof.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: A stainless steel soaking plate, comprising an upper shell, a condensing surface structure, a support column, a liquid wick and a lower shell; The upper shell is a flat plate, and the middle of the lower shell is recessed to form an inner cavity. The upper and lower shells fit together and are sealed to form a heat spreader cavity. A liquid injection port is provided on the side of the lower shell, which is connected to the inner cavity and through which liquid working medium is injected. The upper shell, support column, and lower shell are all made of stainless steel. The condensation surface structure is the inner surface of the upper shell plate, and has a plurality of hydrophobic bud structures on the surface; The liquid wick is a stainless steel fiber felt with a plurality of hydrophilic nano-needle structures, and the stainless steel fiber felt is connected to the bottom surface of the inner cavity of the lower shell plate; The support column is arranged on the bottom surface of the inner cavity of the lower shell plate; The stainless steel fiber felt is provided with through holes corresponding to the support columns, and the upper ends of the support columns pass through the through holes on the stainless steel fiber felt and are connected to the inner surface of the upper shell plate; The liquid working medium is filled in the closed inner cavity formed by the upper shell plate and the lower shell plate.

[0006] In a preferred embodiment, the thickness of the upper shell plate is 0.03-0.05 mm, the thickness of the lower shell plate is 0.12-0.15 mm, the depth of the heat sink cavity is 0.07-0.12 mm, and the thickness of the upper shell plate is the same as the thickness of the lower shell plate after deducting the cavity depth.

[0007] Stainless steel shell plates of appropriate thickness can significantly reduce the heat conduction distance while ensuring structural strength, thereby reducing the impact of poor thermal conductivity of stainless steel on the overall heat transfer performance of the heat sink.

[0008] In a preferred embodiment, the depth of the inner cavity of the lower shell plate is 0.01-0.09 mm greater than the thickness of the stainless steel fiber felt.

[0009] In a preferred embodiment, the thickness of the stainless steel fiber felt is 0.03-0.06 mm, and the equivalent micropore radius of the stainless steel fiber felt is about 6-10 μm, preferably 8-10 μm.

[0010] Under the premise of ensuring the heat transfer performance and stability of the product, the thickness of the stainless steel fiber felt should be as thin as possible. Too thick stainless steel fiber felt will increase the overall thickness of the heat spreader, prolong the preparation time of the subsequent super-hydrophilic absorbent core, thereby reducing the overall heat transfer efficiency of the heat spreader and failing to meet the demand for lighter products.

[0011] In a preferred embodiment, the stainless steel fiber felt is made of stainless steel fibers with a wire diameter of 5-15 μm and a pore size of 10-100 μm.

[0012] The original stainless steel fiber has a smooth surface and a diameter of about 5-15μm. After pressing and high-temperature sintering, it forms a three-dimensional porous structure with a pore size of 10-100μm.

[0013] In a preferred embodiment, the material of the bud structure is copper hydroxide.

[0014] In a preferred embodiment, the diameter of the bud structure is 2-8 μm, the height is 2-5 μm, and the torsion angle is 5°-45°.

[0015] In a preferred embodiment, the nano-needle-like structure has a length of 1.5-2 μm, a bottom diameter of 0.1-0.2 μm, a tip diameter of 0.05-0.15 μm, and is radial.

[0016] In a preferred embodiment, the liquid working medium is one or more of deionized water, propylene glycol, ethylene glycol or liquid nitrogen.

[0017] Based on the same inventive concept, the present invention also claims protection for a method for preparing the stainless steel soaking plate, comprising the following steps: S1, performing double-anodic electrodeposition and double-cathode electrochemical oxidation on the inner surface of the upper shell plate in sequence to obtain a condensation surface structure with a flower bud structure; S2. Etching a support column structure on the inner surface of the lower shell plate, and fixing a stainless steel fiber felt on the inner surface of the lower shell plate to obtain a lower shell plate fixed with the stainless steel fiber felt; S3, performing double-anodic electrodeposition and double-cathode electrochemical oxidation on the surface of the stainless steel fiber felt in sequence to obtain a stainless steel fiber felt with a nano-needle structure on the surface, which is used as a liquid wick; S4. Assemble the upper shell plate with the flower bud structure and the lower shell plate with the nano-needle structure, seal, evacuate, and inject liquid working medium to obtain a stainless steel soaking plate.

[0018] In a preferred embodiment, in step S1, the electrolyte for dual-anode electrodeposition includes 0.6-1.0 mol / L of CuSO4•5H2O and 0.9-1.3 mol / L of H2SO4.

[0019] In a preferred embodiment, in step S1, the temperature of the double anode electrodeposition is 20-30°C, and the constant current density is 15-25 mA / cm 2 , the deposition time is 10-60 minutes, preferably 20-40 minutes.

[0020] Use a non-conductive clamp to clamp the upper shell of the stainless steel soaking plate, connect the negative pole of the power supply to the upper shell of the stainless steel soaking plate, connect the positive pole of the power supply to pure copper and place them on the left and right sides of the stainless steel upper shell, immerse them in the electrolyte, ensure that only the inner side of the upper shell of the soaking plate is in contact with the electrolyte, and perform double-anodic electrodeposition. Since the surface of the original stainless steel plate is smooth, after power is applied, the copper ions in the electrolyte solution will be attracted by the anode surface and deposited on the inner surface of the upper shell to form a copper coating.

[0021] In a preferred embodiment, in step S1, the electrolyte for dual cathode electrochemical oxidation is a 1-2 mol / L NaOH solution.

[0022] In a preferred embodiment, in step S1, the temperature of the double cathode electrochemical oxidation is 20-30°C, and the constant current density is 5-15 mA / cm 2 , the deposition time is 5-15 minutes.

[0023] The electroplated stainless steel soaking plate is clamped with a non-conductive fixture. The positive pole of the power supply is connected to the soaking plate. The negative pole of the power supply is connected to pure copper and placed on the left and right sides of the stainless steel upper shell. The plate is immersed in an electrolyte for dual-cathode electrochemical oxidation. After electrochemical oxidation, the copper coating on the surface of the stainless steel plate changes structure, forming a dense "bud-shaped" copper hydroxide structure. The size of the bud structure is affected by the electroplating time. As the electroplating time increases, the average size of the bud structure also increases.

[0024] After electrochemical treatment, a "bud"-shaped copper hydroxide structure is deposited on the inner surface of the stainless steel upper shell plate. This structure significantly increases the surface roughness of the plate, making the condensation surface structure on the inner surface of the upper shell plate super-hydrophobic to water infiltration.

[0025] In a preferred embodiment, in step S2, the stainless steel fiber felt is fixed to the inner surface of the lower shell plate by laser welding.

[0026] In a preferred embodiment, in step S3, the electrolyte for dual-anode electrodeposition includes 0.6-1.0 mol / L of CuSO4•5H2O and 0.9-1.3 mol / L of H2SO4.

[0027] In a preferred embodiment, in step S3, the temperature of the double anode electrodeposition is 20-30°C, and the constant current density is 15-25 mA / cm 2 , the deposition time is 20-40 minutes.

[0028] Wrap the stainless steel vapor chamber lower shell with a non-conductive clamp, connect the negative power supply to the stainless steel vapor chamber lower shell, and connect the positive power supply to pure copper and place it on the left and right sides of the stainless steel lower shell. Immerse it in an electrolyte, ensuring that only the stainless steel fiber felt welded to the inner side of the vapor chamber lower shell comes into contact with the electrolyte. Double-anodic electrodeposition is performed. Due to the different surface porous structures of the stainless steel fiber and the stainless steel plain plate, the stainless steel fiber will produce a different surface structure than the stainless steel plain plate during the same treatment process. During the electroplating process, the uneven distribution of charge within the porous structure causes copper particles to nucleate and grow unevenly across the fiber surface, forming a "beaded" transition structure - copper particles. The copper particles are approximately 10-20μm in diameter, significantly increasing the surface roughness of the fiber.

[0029] In a preferred embodiment, in step S3, the electrolyte for cathode electrochemical oxidation is a 1-2 mol / L NaOH solution.

[0030] In a preferred embodiment, in step S3, the temperature of the double cathode electrochemical oxidation is 20-30°C, and the constant current density is 5-15 mA / cm2 , the deposition time is 5-15 minutes.

[0031] After electrochemical treatment, a "velvety" nano-needle liquid-absorbing core structure is deposited on the inner side of the stainless steel fiber felt. This structure makes the liquid-absorbing core deposited on the lower shell of the heat spreader super-hydrophilic to water.

[0032] The beneficial effects of the present invention are: (1) The present invention deposits a dense bud-shaped copper hydroxide structure as the condensation surface structure on the heat spreader condensation surface structure by electrochemical deposition. The structure has super hydrophobicity and can effectively increase the speed at which the steam at the condensation end condenses into droplets, thereby ensuring a long-lasting liquid-vapor-liquid cycle.

[0033] (2) The present invention uses electrochemical deposition to produce a nano-scale needle-like copper hydroxide structure on the surface of a stainless steel fiber felt fixed to the bottom surface of the lower shell cavity. The stainless steel fiber felt with this structure on its surface is used as a liquid wick, and the surface of the liquid wick has super-hydrophilicity. The present invention overcomes the inherent hydrophobicity of the stainless steel liquid wick, effectively increases the capillary pressure of the liquid wick, and increases the speed at which the liquid working medium after condensation flows back to the evaporation end, thereby enhancing the overall heat transfer performance of the heat spreader.

[0034] (3) After electrochemical deposition, the bud-shaped copper hydroxide coating on the inner surface of the upper shell plate and the needle-shaped copper hydroxide structure on the inner side of the lower shell plate and the surface of the stainless steel fiber felt can isolate water (a liquid working medium commonly used in stainless steel heat sinks) from contacting the stainless steel substrate on the inner wall of the chamber, thereby preventing the occurrence of hydrogen evolution reaction, ensuring the reliability of the product and improving the service life of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is the overall structural diagram of the stainless steel soaking plate of the present invention; Figure 2 A perspective view of a stainless steel soaking plate according to the present invention; Figure 3 is a cross-sectional view of a stainless steel soaking plate of the present invention; Figure 4 This is the morphology of the stainless steel upper shell after electrochemical deposition; Figure 5 This is the morphology of stainless steel fiber felt after electrochemical deposition; Figure 6 Schematic diagram comparing the wettability of a stainless steel vapor chamber in Example 1 of the present invention to deionized water; (a) stainless steel plain plate; (b) condensing surface structure; (c) stainless steel fiber; (d) super-hydrophilic wick structure; Among them, 1-upper shell plate; 2-stainless steel fiber felt; 3-lower shell plate, 11-condensation surface structure; 21-liquid absorption core; 31-support column, 4-liquid injection port. DETAILED DESCRIPTION

[0036] The present invention is not limited to the following specific embodiments. Based on the disclosure of the present invention, a person skilled in the art may adopt a variety of other specific embodiments to implement the present invention. Any simple changes or modifications made to the design structure and concept of the present invention fall within the scope of protection of the present invention. It should be noted that the embodiments and features of the embodiments of the present invention may be combined with each other unless they conflict. Example 1

[0037] like Figures 1 to 3 As shown, a stainless steel vapor chamber comprises an upper shell 1, a condensing surface structure 11, a support column 31, a liquid wick 21 and a lower shell 3; The upper shell plate 1 is a flat plate, and the middle part of the lower shell plate 3 is recessed to form an inner cavity. The edge of the upper shell plate 1 and the lower shell plate 3 are in contact with each other and are sealed to form a heat plate cavity. A liquid injection port 4 is opened on the side of the lower shell plate 3, and the liquid injection port 4 is connected to the inner cavity. The liquid working medium is injected through the liquid injection port 4. The upper shell plate 1, support column 31, and lower shell plate 3 are all made of stainless steel. The condensation surface structure 11 is located on the inner surface of the upper shell plate and has a plurality of hydrophobic bud structures on the surface; The liquid wick 21 is a stainless steel fiber felt 2 with a plurality of hydrophilic nano-needle structures, connected to the lower shell plate 3, and the thickness of the stainless steel fiber felt 2 is less than the depth of the inner cavity; The support column 31 is provided on the inner surface of the lower shell plate 3; The stainless steel fiber felt 2 is provided with a through hole corresponding to the support column 31, and the upper end of the support column 31 passes through the through hole on the stainless steel fiber felt 2 and is connected to the upper shell plate 1; The liquid working medium is filled in the closed inner cavity formed by the upper shell plate 1 and the lower shell plate 3.

[0038] The thickness of the upper shell 1 is 0.05 mm, the thickness of the lower shell 3 is 0.15 mm, the inner cavity depth is 0.1 mm, and the thickness of the stainless steel fiber felt 2 is 0.05 mm.

[0039] Stainless steel fiber felt is made of stainless steel fibers with a diameter of 5-10μm and a pore size of 50-60μm. The equivalent micropore radius of the stainless steel fiber felt is about 8μm.

[0040] The material of the bud structure is copper hydroxide.

[0041] The nano needle-like structure has a length of 1.5-2 μm, a bottom diameter of 0.1-0.2 μm, a tip diameter of 0.05-0.15 μm, and is radial.

[0042] The liquid working medium is deionized water.

[0043] The preparation process of the stainless steel soaking plate includes the following steps: 1. The specific preparation process of the condensation surface structure is as follows: Step 1: Cut the stainless steel plate into pieces with a size of 100 mm*20 mm*0.05 mm to obtain a stainless steel substrate.

[0044] Step 2: dissolving copper sulfate pentahydrate in water, controlling the concentration of copper ions at 0.8 mol / L, and adding a sulfuric acid solution having a sulfuric acid concentration of 1.1 mol / L to obtain an electrolyte for dual-anode electrodeposition.

[0045] Step 3: dissolving sodium hydroxide in water to obtain a double-cathode electrochemical oxidation sodium hydroxide electrolyte with a concentration of 1.0 mol / L.

[0046] Step 4: Place the stainless steel plate obtained in step 1 in the solution in step 2, and apply a power supply for double-anodic electrodeposition. The negative electrode of the power supply is connected to the stainless steel plate, and the positive electrode is connected to two 5 mm*10 mm pure copper sheets. The constant current density is 20 mA / cm 2 , the electrodeposition time is 30 minutes, and a stainless steel plate with a copper coating on the surface is obtained.

[0047] Step 5: Place the stainless steel plate obtained in step 4 in the solution of step 3, and apply a power supply for double cathode electrochemical oxidation. The positive electrode of the power supply is connected to the treated stainless steel plate, and the negative electrode is connected to two 5 mm*10 mm pure copper sheets. The constant current density is 10 mA / cm 2 , the plating time is 10 minutes, and the Figure 4 The surface of the superhydrophobic absorbent core shown is covered with a "bud"-shaped copper hydroxide structure. The average diameter of the "bud"-shaped copper hydroxide structure is about 4 μm, the average height is about 5 μm, and the average torsion angle is about 15°.

[0048] 2. The specific preparation process of the super-hydrophilic absorbent core is similar to that of the super-hydrophobic condensation surface structure, with the only difference being: The electrochemical deposition object is the stainless steel fiber felt spot-welded on the stainless steel lower shell plate.

[0049] The size of the stainless steel plate obtained in step 1 is 100 mm*20 mm*0.15 mm.

[0050] The surface structure of the stainless steel fiber felt obtained in step 4 is a "beaded" copper structure.

[0051] The super hydrophilic absorbent core structure obtained in step 5 is as follows: Figure 5As shown, a "hairy" copper hydroxide nanoneedle structure is formed on the fiber surface. The average length of the nanoneedles is 1.5 μm, the average diameter at the bottom is 0.15 μm, and the average diameter at the tip is 0.08 μm, and they are radial. Example 2

[0052] The difference from Example 1 is: The deposition time for the superhydrophobic condensation surface structure is longer. The electrodeposition time in step 4 of the superhydrophobic condensation surface structure preparation process is 60 minutes. The electrolyte concentration of the double-anode electrodeposition is 0.6 mol / L of CuSO4·5H2O and 0.9 mol / L of H2SO4.

[0053] Other details are the same as in Example 1. Example 3

[0054] The difference from Example 1 is: The deposition time for the superhydrophobic condensation surface structure is shorter. The electrodeposition time in step 4 during the preparation of the superhydrophobic condensation surface structure is 10 minutes. The electrolyte for the dual-anode electrodeposition includes a concentration of 1.0 mol / L of CuSO₄•5H₂O and a concentration of 1.3 mol / L of H₂SO₄. Other conditions are the same as in Example 1. Example 4

[0055] The difference from Example 1 is: The deposition time of the super-hydrophilic wick structure is longer. The electrodeposition time in step 4 during the preparation of the super-hydrophilic wick is 60 minutes. The electrolyte for the dual-anode electrodeposition contains 0.6 mol / L of CuSO₄•5H₂O and 0.9 mol / L of H₂SO₄. Other conditions are the same as in Example 1. Example 5

[0056] The difference from Example 1 is: The deposition time of the super-hydrophilic wick structure is shortened. The dual-cathode electrochemical oxidation time in step 5 of the super-hydrophilic wick preparation process is 15 minutes. The electrolyte for the dual-cathode electrochemical oxidation is a 2 mol / L NaOH solution. Other modifications are the same as in Example 1.

[0057] Figure 6 Schematic diagram of the wettability of the wicks prepared according to Examples 1-5 to deionized water. The results show that, compared with the hydrophobic surface of normal stainless steel fiber felt, the surface of the stainless steel fiber after electrochemical treatment has a micro-nano structure, making the wettability to deionized water super-hydrophilic and providing good capillary properties. The stainless steel plate after electrochemical treatment also has more hydrophobic wettability, which can provide a faster vapor-liquid conversion rate. At the same time, the copper hydroxide structure of the wick can also improve the compatibility of stainless steel with water vapor.

[0058] Comparative Example 1 The difference from Example 1 is: The lower cover of the stainless steel vapor chamber uses the super-hydrophilic liquid wick of the present invention as the liquid wick, and the upper cover uses a stainless steel plate as the condensation surface. Other aspects are the same as in Example 1.

[0059] Comparative Example 2 The difference from Example 1 is: The super-hydrophilic absorbent core structure is different. The super-hydrophilic absorbent core structure is a needle-like copper oxide nanoneedle structure formed on the fiber surface. The preparation method of the needle-like copper oxide nanoneedle structure formed on the fiber surface is: The previous steps 1-4 are the same as in Example 1.

[0060] Step 5: Immerse the stainless steel plate obtained in step 4 in a mixed solution of 2.5 mol / L potassium hydroxide and 0.065 mol / L potassium persulfate at 70°C for 30 minutes. After taking it out, washing it, and baking it in a high-temperature furnace at 180°C for 2 hours, a super-hydrophilic absorbent core with a needle-like copper oxide nanoneedle structure on the surface is obtained. The diameter of the needle-like nanoparticles formed is 500~800 μm, and the equivalent micropore radius is about 8 μm.

[0061] Comparative Example 3 The difference from Example 1 is: The deposition time for the superhydrophobic condensation surface structure is longer. The electrodeposition time in step 4 of the superhydrophobic condensation surface structure preparation process is 90 minutes. The electrolyte concentration of the dual-anode electrodeposition is 0.6 mol / L of CuSO₄•5H₂O and 0.9 mol / L of H₂SO₄.

[0062] Comparative Example 4 The difference from Example 1 is: The deposition time for the superhydrophobic condensation surface structure is shortened. The electrodeposition time in step 4 of the superhydrophobic condensation surface structure preparation process is 5 minutes. The electrolyte concentration of the dual-anode electrodeposition is 0.6 mol / L of CuSO₄•5H₂O and 0.9 mol / L of H₂SO₄.

[0063] The performance of the vapor chambers prepared in Examples 1-5 and Comparative Examples 1-6 was tested. The vapor chamber heat transfer performance test consisted of a power supply, a temperature sensor (measuring temperature range 0-100°C with a measurement accuracy of 0.1°C), and a heat source. The heat source power was 5W, and the test points were mainly tested at two locations: one near the heat source end T1 and the other far from the heat source end T2. The time it took for the heat source to stabilize and work was recorded, which was recorded as the start-up time t. The temperature equalization performance was determined by the temperature difference T1-T2 after the vapor chamber stabilized and was recorded as ΔTmax.

[0064]

[0065] As can be seen in Table 1, the comprehensive heat transfer performance of the examples is superior to that of the comparative examples, with the best temperature uniformity and fastest startup speed. The super-hydrophilic wick on the vapor chamber's evaporation end provides sufficient capillary pressure, ensuring the vapor chamber's overall temperature uniformity. The super-hydrophobic structure on the condensation end accelerates liquid backflow from the vapor chamber, making the vapor chamber start up even faster.

[0066] Comparative Example 3 shows that the electroplating time of the stainless steel fiber felt is too long, and larger copper particles are formed at the intersection of the stainless steel fibers, which reduces the porosity of the stainless steel fibers and is easy to fall off, thereby destroying the integrity of the coating. At the same time, it affects the formation of micro-nano structures on the surface of the stainless steel fibers during subsequent electrochemical oxidation, causing the stainless steel heat sink to fail.

[0067] Comparative Example 4 shows that the electrodeposition time of the stainless steel fiber felt is too short, and a dense surface film cannot form on the stainless steel surface, which cannot provide a good insulation effect. Incomplete coating can cause hydrogen evolution reaction when the stainless steel contacts the working medium deionized water, thus affecting the overall reliability of the heat sink.

[0068] It should be noted that the above embodiments are merely examples for the purpose of clearly illustrating the present invention and are not intended to limit the embodiments of the present invention. A person skilled in the art would be able to make other variations or modifications based on the above description. It is not possible to enumerate all embodiments here. Any obvious variations or modifications arising from the technical solution of the present invention remain within the scope of protection of the present invention.

Claims

1. A stainless steel soaking plate, characterized in that: It includes an upper shell plate, a condensing surface structure, a supporting column, a liquid wick and a lower shell plate; The upper shell is a flat plate, and the middle of the lower shell is recessed to form an inner cavity. The upper and lower shells fit together and are sealed to form a heat spreader cavity. A liquid injection port is provided on the side of the lower shell, which is connected to the inner cavity and through which liquid working medium is injected. The upper shell, support column, and lower shell are all made of stainless steel. The condensation surface structure is the inner surface of the upper shell plate, and has a plurality of hydrophobic bud structures on the surface; The liquid wick is a stainless steel fiber felt with a plurality of hydrophilic nano-needle structures, and the stainless steel fiber felt is connected to the bottom surface of the inner cavity of the lower shell plate; The support column is arranged on the bottom surface of the inner cavity of the lower shell plate; The stainless steel fiber felt is provided with through holes corresponding to the support columns, and the upper ends of the support columns pass through the through holes on the stainless steel fiber felt and are connected to the inner surface of the upper shell plate; The liquid working medium is filled in the closed inner cavity formed by the upper shell plate and the lower shell plate.

2. The stainless steel soaking plate according to claim 1, characterized in that: The thickness of the upper shell plate is 0.03-0.05 mm, the thickness of the lower shell plate is 0.12-0.15 mm, the depth of the heat sink cavity is 0.07-0.12 mm, and the thickness of the upper shell plate is the same as the thickness of the lower shell plate after deducting the cavity depth.

3. The stainless steel soaking plate according to claim 1, characterized in that: The thickness of the stainless steel fiber felt is 0.03-0.06 mm, and the equivalent micropore radius of the stainless steel fiber felt is about 6-10 μm. The stainless steel fiber felt is paved with stainless steel fibers with a wire diameter of 5-15 μm, and the pore diameter is 10-100 μm.

4. The stainless steel soaking plate according to claim 1, characterized in that: The material of the flower bud structure is copper hydroxide; the diameter of the flower bud structure is 2-8 μm, the height is 2-5 μm, and the torsion angle is 5°-45°.

5. The stainless steel soaking plate according to claim 1, characterized in that: The nano needle-like structure has a length of 1.5-2 μm, a bottom diameter of 0.1-0.2 μm, a tip diameter of 0.05-0.15 μm, and is radial.

6. The method for preparing a stainless steel soaking plate according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1, performing double-anodic electrodeposition and double-cathode electrochemical oxidation on the inner surface of the upper shell plate in sequence to obtain an upper shell plate with a bud structure; S2. Etching a support column structure on the inner surface of the lower shell plate, and fixing a stainless steel fiber felt on the inner surface of the lower shell plate to obtain a lower shell plate fixed with the stainless steel fiber felt; S3, performing double-anodic electrodeposition and double-cathode electrochemical oxidation on the surface of the stainless steel fiber felt in sequence to obtain a stainless steel fiber felt with a nano-needle structure on the surface, which is used as a liquid wick; S4. Assemble the upper shell plate with the flower bud structure and the lower shell plate with the nano-needle structure liquid wick, seal, evacuate, and inject liquid working medium to obtain a stainless steel heat sink.

7. The preparation method according to claim 6, characterized in that In step S1, the electrolyte for dual-anode electrodeposition includes 0.6-1.0 mol / L CuSO4•5H2O and 0.9-1.3 mol / L H2SO4; the temperature for dual-anode electrodeposition is 20-30°C, and the constant current density is 15-25 mA / cm 2 , the deposition time is 10-60 minutes.

8. The preparation method according to claim 6, characterized in that In step S1, the electrolyte for the dual cathode electrochemical oxidation is a 1-2 mol / L NaOH solution; the temperature for the dual cathode electrochemical oxidation is 20-30°C, and the constant current density is 5-15 mA / cm 2 , the deposition time is 5-15 minutes.

9. The preparation method according to claim 6, characterized in that In step S3, the electrolyte for dual-anode electrodeposition includes 0.6-1.0 mol / L CuSO4•5H2O and 0.9-1.3 mol / L H2SO4; the temperature for dual-anode electrodeposition is 20-30°C, and the constant current density is 15-25 mA / cm 2 , the deposition time is 20-40 minutes.

10. The preparation method according to claim 6, characterized in that In step S3, the electrolyte for cathode electrochemical oxidation is a 1-2 mol / L NaOH solution; the temperature for dual cathode electrochemical oxidation is 20-30°C, and the constant current density is 5-15 mA / cm 2 , the deposition time is 5-15 minutes.

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