Method for producing single-sided nano carbon radiating fin through electrophoresis

Abstract

The invention relates to the technical field of electrophoresis of cooling fins, in particular to a method for producing a single-sided nanocarbon cooling fin through electrophoresis, which comprises the following steps: stamping and slicing an aluminum alloy to obtain a cooling fin workpiece; single-sided adhesive insulation paper is attached to the back face of the cooling fin workpiece; the method comprises the following steps: uniformly hanging a plurality of cooling fin workpieces on a hook of a hanger at intervals, and then carrying out demolding and oil removal treatment, water washing and spraying treatment, ultrasonic treatment and clean water cleaning treatment to obtain pretreated cooling fin workpieces; performing electrophoretic deposition treatment by taking the pretreated cooling fin workpiece as an anode, an inert material as a cathode and a water-based carbon nano coating as an electrolyte to obtain an electrophoretic cooling fin workpiece; and after an electrophoresis cooling fin workpiece is subjected to clean water cleaning treatment and baking curing treatment, the workpiece is taken down from the hook of the hanging tool in a hanging mode, then the single-face adhesive insulation paper is torn off, and the single-face nanometer carbon cooling fin is obtained. The carbon nano coating obtained by the method is uniform and thin in thickness, low in cost and high in efficiency.

Description

Technical Field

[0001] This invention relates to the field of electrophoresis technology for heat sinks, and specifically to a method for producing single-sided nano-carbon heat sinks by electrophoresis. Background Technology

[0002] Electrophoretic coatings have the advantages of being full, uniform, flat, and smooth. Their hardness, adhesion, corrosion resistance, impact resistance, and penetration performance are significantly better than other coating processes.

[0003] Heat sinks are typically made of aluminum alloy heat dissipation material. With increasingly demanding heat dissipation requirements and miniaturized product designs, a nano-carbon heat dissipation coating needs to be sprayed or electrophoretically applied during the aluminum extrusion molding process to transfer heat through radiation and improve heat dissipation. If a single-sided carbon nano-coating is achieved using a spraying process, the film thickness is difficult to control, typically ranging from 40-80µm, containing micropores, and only achieving 50% material utilization, resulting in significant waste. Excess carbon nano-coating material is not recyclable, leading to high raw material costs and low utilization. Furthermore, the need to add organic solvents such as thinner for dilution is environmentally unfriendly, and the production process generates VOC emissions and dust. The spraying process also requires high electrostatic safety standards. On the other hand, electrophoresis, a traditional method, is usually performed in an open or semi-open environment, allowing the solution to easily contact all surfaces of the material, resulting in carbon nano-coating deposition on all sides, which is costly. Even with attempts to achieve single-sided deposition through localized electric field control, it is difficult to completely prevent particle deposition on non-target surfaces, making it challenging to obtain a single-sided carbon nano-coating. Summary of the Invention

[0004] In order to overcome the shortcomings and deficiencies of the existing technology, the present invention aims to provide a method for producing single-sided nano-carbon heat sinks by electrophoresis. This preparation method is simple to operate, easy to control, has high production efficiency, low production cost, and can be used for large-scale production.

[0005] The objective of this invention is achieved through the following technical solution: a method for producing single-sided nano-carbon heat sinks by electrophoresis, comprising the following steps:

[0006] (S1) Take aluminum alloy and stamp and slice it to obtain heat sink workpiece;

[0007] (S2) Apply single-sided adhesive insulating paper to the back of the heat sink workpiece;

[0008] (S3) Hang multiple heat sink workpieces evenly on the hooks of the hanger, and then perform degreasing, water washing and spraying, ultrasonic treatment and clean water cleaning to obtain pre-treated heat sink workpieces.

[0009] (S4) Using the pretreated heat sink workpiece as the anode, an inert material as the cathode, and water-based carbon nanotube coating as the electrolyte, electrophoretic deposition is performed to obtain the electrophoretic heat sink workpiece.

[0010] (S5) After cleaning the electrophoretic heat sink workpiece with clean water and baking and curing, the workpiece is taken out from the hook of the hanger and the single-sided adhesive insulation paper is removed to obtain a single-sided nano carbon heat sink.

[0011] The present invention discloses a method for producing single-sided nano-carbon heat sinks via electrophoresis. A single-sided adhesive insulating paper is attached to the back of the heat sink workpiece, effectively modifying the back surface to repel carbon nanoparticles. Since electrophoresis involves the deposition of positively charged resin and pigment particles onto the heat sink surface under an electric field, forming a uniform coating film, the single-sided adhesive insulating paper prevents the deposition of positively charged resin and pigment particles. This method not only utilizes the advantages of electrophoresis to produce single-sided coated heat sinks, improving product quality, but also offers lower costs compared to traditional electrophoretic double-sided carbon nanoparticle coatings and spray-applied single-sided carbon nanoparticle coatings. It also meets environmental protection requirements, improves the safety level of the production workshop, and eliminates the need to consider electrostatic safety requirements of spray-applied processes, ensuring the safety of employees. Multiple heat sink workpieces are suspended at even intervals to prevent collisions or coating loss, ensuring a uniform electric field distribution and resulting in a coating film of consistent thickness. After degreasing, water washing, ultrasonic treatment, and rinsing with clean water, surface contaminants are removed from the heat sink workpieces, ensuring heat dissipation performance and equipment safety. Using water-based carbon nanotube coatings as the electrolyte achieves a utilization rate of 90%-95%, reducing VOC emissions. During electrophoretic deposition, water electrolysis on the anode surface generates OH-, forming a highly alkaline boundary layer. Positively charged resin particles (encapsulating pigments) migrate towards the anode (heat sink), where they neutralize and precipitate uniformly onto the heat sink surface, including the fin gaps. The electric field drives water molecules to seep out from the coating's capillaries, densifying the paint film. If the electrophoretic coating contains trace amounts of moisture, vaporization during high-temperature reflow soldering can cause blistering or substrate cracking. However, with this solution, the electrophoretic heat sink workpiece undergoes water cleaning and baking curing, which evaporates residual moisture, reducing the welding defect rate by more than 30%.

[0012] Preferably, in step (S2), the single-sided adhesive insulating paper covers the back of the heat sink workpiece and has an easy-to-tear edge.

[0013] The above technical solution includes a pre-reserved tear-off edge to facilitate the subsequent removal of the single-sided adhesive insulating paper from the back of the heat sink workpiece along this edge. Furthermore, the single-sided adhesive insulating paper includes, but is not limited to, single-sided adhesive-backed insulating paper, utilizing its high-temperature resistance and insulation properties to prevent coating deposition during electrophoresis.

[0014] Preferably, in step (S3), the hanger is a mechanically assembled hanger, the hanger is made of corrosion-resistant stainless steel 316L, and the hook of the hanger is a spring steel wire hook with a hook tip angle of 45°.

[0015] Currently, in the traditional electrophoresis hanging process, similar processes directly suspend the heat sink on the hanger hook. The workpiece is prone to shaking, which can lead to collision damage. Furthermore, after electrophoresis, the hook is completely covered by an insulating varnish layer. After each batch of production, the hanger needs to be stripped of the varnish (such as through chemical dissolution or mechanical polishing), which significantly increases production costs and time consumption. If copper soldering or tin soldering is used to assemble the hook, the high temperature of copper soldering causes the spring hook to anneal and lose its elasticity, while tin soldering becomes brittle and falls off at the electrophoresis drying temperature (≥160℃). The above technical solution utilizes corrosion-resistant 316L stainless steel to reduce heavy metal pollution and extend service life. The hanger design features a double-sided cleaning structure, recovering and filtering floating paint for reuse, reducing paint waste. By replacing traditional welding methods with mechanically assembled hangers, durability is improved (no damage after 3 years of continuous use) and maintenance costs are reduced. In addition, the spring steel wire hooks with a 45° angled tip can buffer vibration or impact, preventing the heat sink from shifting or damaging the coating due to mechanical stress in the electrophoresis tank. Compared to right-angle hooks, which have a smaller contact area, insufficient friction, and are prone to falling off under slight vibration, this solution optimizes the contact area with a 45° angled tip, increasing friction and preventing slippage or shaking during suspension. The workpiece rotation scratches the paint layer at the contact point, avoiding paint stripping and ensuring conductivity stability. Overall, it avoids workpiece collisions or coating loss, ensuring uniform electric field distribution, thereby obtaining a paint film with a more consistent thickness, improving coating adhesion, corrosion resistance, and production efficiency.

[0016] Preferably, in step (S3), the degreasing treatment is to remove oil stains from the heat sink workpiece using a neutral degreasing agent; the water washing and spraying treatment is to spray the heat sink workpiece with an aqueous solution of corrosion inhibitor with a concentration of 0.1wt%-0.2wt%.

[0017] Using the above technical solution, the neutral degreaser is selected from Bio-oil Clean D3 to remove grease, dirt, and other contaminants without corroding the substrate. This avoids residual grease affecting the adhesion of coatings, welds, or passivation treatments, thus preventing delamination or corrosion risks. The corrosion inhibitor is selected from siloxane ketone aluminum corrosion inhibitor AC-3S, which facilitates the formation of a protective film, effectively removes surface-accumulated contaminants, and prevents accelerated oxidation.

[0018] Preferably, in step (S3), the ultrasonic treatment is performed by pulsed ultrasonic cleaning in a cleaning solution at 50-70°C for 5-10 minutes; the water rinsing treatment is performed by removing the cleaning solution from the heat sink workpiece with clean water.

[0019] The above technical solution utilizes the cavitation effect generated by ultrasonic vibration to achieve efficient cleaning and performance optimization. Pulsed ultrasound is emitted intermittently at low frequencies (25-40kHz) and high frequencies (≥80kHz). The low-frequency cavitation bubbles are large and have strong impact, suitable for removing stubborn oil or oxide layers from deep holes in heat sinks. The high-frequency bubbles are fine and dense, resulting in more uniform cleaning and avoiding surface damage. The cleaning solution temperature needs to be controlled at 50-70℃ for 5-10 minutes to activate the cleaning solution and soften the dirt. A biodegradable (citrus-based cleaning agent) is used as the cleaning solution, replacing traditional alkane solvents.

[0020] Preferably, in step (S4), the inert material is graphite or stainless steel, the temperature of the electrophoretic deposition bath is 28-32℃, the initial voltage is 180-220V, the voltage after 1-2 minutes is 280-320V, and the electrophoresis time is 2.5-3 minutes.

[0021] Using the above technical solution, the voltage is increased in stages (initial 180-220V → target 280-320V), prioritizing the coverage of edges and corners to avoid roughness caused by high voltage. The bath temperature is maintained at 28-32℃, and the electrophoresis time is extended to 2.5-3 minutes, which is beneficial for increasing the deposition thickness at the edges and corners. During electrophoresis, water is electrolyzed on the anode surface to generate OH-, forming a highly alkaline boundary layer. Positively charged resin particles (encapsulating pigments) migrate towards the anode (heat sink workpiece). The resin particles neutralize with OH- and precipitate, uniformly depositing on the surface of the heat sink, including the gaps between the fins. The electric field drives water molecules to seep out from the coating capillaries, densifying the paint film.

[0022] Preferably, in step (S4), the water-based carbon nanomaterial coating comprises the following raw materials in parts by weight:

[0023]

[0024]

[0025] Using the above technical solution, water-based resin is used as the matrix and the coating skeleton. If the proportion is too low, the adhesion will be affected; if the proportion is too high, the thermal conductivity will be reduced. This type of water-based resin has a controllable cost and can effectively encapsulate fillers to form a stable coating. Adding 0.5-2 parts of carbon nanotubes can maintain a thermal conductivity of 15-20 W / m·K. If the amount is too low (<0.5%), the thermal conductivity will be insufficient; if the amount is too high (>2%), the cost will be significantly increased and agglomeration will easily occur. The amount of micron-sized alumina added within this range can improve the thermal emissivity to 0.90-0.95, while avoiding the use of expensive materials such as boron nitride, which is beneficial to reducing costs. The carbon nanotube-coated heat sink, which combines aluminum and carbon, can not only conduct heat vertically, but also release heat into the air through lateral thermal radiation using carbon nanotubes. Furthermore, the particle size of the micron-sized alumina is 1-10 μm.

[0026] Preferably, the waterborne resin is a waterborne acrylic resin or a silicone-modified waterborne polyurethane, the dispersant is polyvinylpyrrolidone, and the curing agent is Qirun EH 3504 and / or polyetheramine curing agent T-5000.

[0027] Furthermore, the waterborne acrylic resin is selected from AC6013, and the silicone-modified waterborne polyurethane is selected from Evonik SILIKOPUR 8081.

[0028] Preferably, in step (S5), the water cleaning process involves removing the electrolyte from the heat sink workpiece with clean water; the baking and curing process involves baking at 80±3℃ for 25-35 minutes, then baking at 120±3℃ for 50-70 minutes, then baking at 150±3℃ for 40-50 minutes, and finally cooling down to 80℃ at a rate of less than 5℃ per minute.

[0029] Using the above technical solution, baking cross-links and cures the electrophoretic paint resin, increasing the bonding strength between the coating and the metal substrate by 50%, preventing the heat sink from vibrating and falling off. After curing, the coating forms a dense structure, improving thermal radiation efficiency. If the electrophoretic coating contains trace amounts of moisture, the moisture vaporizes during high-temperature reflow soldering, causing blistering of the coating or cracking of the substrate. However, this solution uses a final baking at 150℃ to evaporate residual moisture, reducing the welding defect rate by more than 30%. In addition, current baking processes often use direct baking at a constant temperature of 150℃. Aluminum alloys have fast thermal conductivity, and a sudden temperature increase causes a difference in the expansion rate between the substrate and the coating. This solution, however, heats from room temperature to 80℃, which helps eliminate temperature differences in the workpiece and pre-dehumidifies. Heating from 80℃ to 120℃ helps evaporate microporous moisture, heating from 120℃ to 150℃ helps cross-link and harden the resin, and cooling from 150℃ to 80℃ at a rate of less than 5℃ per minute helps release thermal stress. Using a stepped heating method (80℃→120℃→150℃) can balance interfacial stress and prevent the formation of microcracks.

[0030] Preferably, in step (S1), the aluminum alloy is made of aluminum alloy 6063; in step (S5), after the single-sided adhesive insulating paper is removed, the back of the single-sided nano carbon heat sink is aluminum white.

[0031] Using the above technical solution, the thermal conductivity of aluminum alloy 6063 is 200-227W. Although this is lower than the thermal conductivity of copper (398W), it offers better cost-effectiveness. A nano-carbon heat dissipation coating is electrophoretically applied during the extrusion molding of the aluminum material, transferring heat through radiation and improving heat dissipation performance.

[0032] The beneficial effects of this invention are as follows:

[0033] The present invention provides a method for producing single-sided nano-carbon heat sinks by electrophoresis. Compared with the spraying process, electrophoresis has a higher film thickness uniformity. The electrophoresis process does not use organic additives, is non-toxic, has no discharge, is water-based and environmentally friendly, and has no VOC emissions. The thickness of the electrophoretic film can be controlled at 12-18 μm. Compared with the spraying process, the thickness is uniform and thin, and it has advantages in material utilization and recyclability. At the same time, it is a single-sided coating, and the cost of single-sided electrophoresis is lower than that of double-sided electrophoresis coating.

[0034] Applying single-sided adhesive insulating paper to the back of the heat sink workpiece modifies its surface, giving it properties that repel carbon nanoparticles. Since electrophoresis deposits positively charged resin and pigment particles onto the heat sink surface under an electric field, forming a uniform paint film, the single-sided adhesive insulating paper prevents these particles from depositing. This not only leverages the advantages of electrophoresis to produce single-sided coated heat sinks, improving product quality, but also offers lower costs compared to traditional electrophoretic double-sided carbon nanoparticle coatings and spray-applied single-sided carbon nanoparticle coatings. It also meets environmental requirements, improves production workshop safety, and eliminates the need to consider electrostatic safety requirements for spray-applied processes, ensuring employee safety. Multiple heat sink workpieces are suspended with even spacing to prevent collisions or coating loss, ensuring a uniform electric field distribution and resulting in a consistent paint film thickness. After degreasing, water washing, ultrasonic treatment, and rinsing, surface contaminants are removed from the heat sink workpieces, ensuring heat dissipation performance and equipment safety. Using water-based carbon nanotube coatings as the electrolyte achieves a utilization rate of 90%-95%, reducing VOC emissions. During electrophoretic deposition, water electrolysis on the anode surface generates OH-, forming a highly alkaline boundary layer. Positively charged resin particles (encapsulating pigments) migrate towards the anode (heat sink), where they neutralize and precipitate uniformly onto the heat sink surface, including the fin gaps. The electric field drives water molecules to seep out from the coating's capillaries, densifying the paint film. If the electrophoretic coating contains trace amounts of moisture, vaporization during high-temperature reflow soldering can cause blistering or substrate cracking. However, with this solution, the electrophoretic heat sink workpiece undergoes water cleaning and baking curing, which evaporates residual moisture, reducing the welding defect rate by more than 30%.

[0035] This method is simple to operate, easy to control, has high production efficiency, low production cost, and can be used for large-scale production. Detailed Implementation

[0036] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments. The content mentioned in the embodiments is not intended to limit the present invention.

[0037] Example 1

[0038] A method for producing single-sided nano-carbon heat sinks by electrophoresis includes the following steps:

[0039] (S1) Take aluminum alloy and stamp and slice it to obtain heat sink workpiece;

[0040] (S2) Apply single-sided adhesive insulating paper to the back of the heat sink workpiece;

[0041] (S3) Hang multiple heat sink workpieces evenly on the hooks of the hanger, and then perform degreasing, water washing and spraying, ultrasonic treatment and clean water cleaning to obtain pre-treated heat sink workpieces.

[0042] (S4) Using the pretreated heat sink workpiece as the anode, an inert material as the cathode, and water-based carbon nanotube coating as the electrolyte, electrophoretic deposition is performed to obtain the electrophoretic heat sink workpiece.

[0043] (S5) After cleaning the electrophoretic heat sink workpiece with clean water and baking and curing, the workpiece is taken out from the hook of the hanger and the single-sided adhesive insulation paper is removed to obtain a single-sided nano carbon heat sink.

[0044] In step (S2), the single-sided adhesive insulating paper covers the back of the heat sink workpiece and has an easy-to-tear edge. The single-sided adhesive insulating paper is single-sided adhesive-backed insulating paper.

[0045] In step (S3), the hanger is a mechanically assembled hanger, the hanger is made of corrosion-resistant stainless steel 316L, and the hook of the hanger is a spring steel wire hook with a hook tip angle of 45°.

[0046] In step (S3), the degreasing treatment involves using a neutral degreasing agent (Bio-oilclean D3) to remove oil stains from the heat sink workpiece; the water washing and spraying treatment involves spraying the heat sink workpiece with an aqueous solution of a 0.1wt% corrosion inhibitor (siloxane ketone aluminum corrosion inhibitor ac-3s).

[0047] In step (S3), the ultrasonic treatment involves pulsed ultrasonic cleaning for 6 minutes in a cleaning solution (citrus-based cleaning agent) at 60°C; the water rinsing treatment involves rinsing the heat sink workpiece with clean water to remove the cleaning solution. The pulsed ultrasonic waves are emitted intermittently at low frequency (25kHz) and high frequency (80kHz).

[0048] In step (S4), the inert material is graphite, the temperature of the electrophoretic deposition bath is 30°C, the initial voltage is 200V, the voltage is 320V after 1 minute, and the electrophoresis time is 2.5 minutes.

[0049] In step (S4), the water-based carbon nanomaterial coating comprises the following raw materials in parts by weight:

[0050]

[0051] The method for preparing the waterborne carbon nanotube coating includes mixing waterborne resin, deionized water, dispersant, carbon nanotubes and micron-sized alumina evenly according to the weight parts, and then adding curing agent and mixing evenly to obtain the waterborne carbon nanotube coating.

[0052] The particle size of micron-sized alumina is 5 μm.

[0053] The waterborne resin is silicone-modified waterborne polyurethane SILIKOPUR 8081, the dispersant is polyvinylpyrrolidone, and the curing agent is Qirun EH 3504.

[0054] In step (S5), the water cleaning process is to remove the electrolyte from the heat sink workpiece with clean water; the baking and curing process is to bake at 80°C for 30 minutes, then at 120°C for 60 minutes, then at 150°C for 45 minutes, and finally cool down to 80°C at a rate of less than 5°C per minute.

[0055] In step (S1), the aluminum alloy is made of aluminum alloy 6063; in step (S5), after the single-sided adhesive insulating paper is removed, the back of the single-sided nano carbon heat sink is aluminum white.

[0056] Example 2

[0057] A method for producing single-sided nano-carbon heat sinks by electrophoresis includes the following steps:

[0058] (S1) Take aluminum alloy and stamp and slice it to obtain heat sink workpiece;

[0059] (S2) Apply single-sided adhesive insulating paper to the back of the heat sink workpiece;

[0060] (S3) Hang multiple heat sink workpieces evenly on the hooks of the hanger, and then perform degreasing, water washing and spraying, ultrasonic treatment and clean water cleaning to obtain pre-treated heat sink workpieces.

[0061] (S4) Using the pretreated heat sink workpiece as the anode, an inert material as the cathode, and water-based carbon nanotube coating as the electrolyte, electrophoretic deposition is performed to obtain the electrophoretic heat sink workpiece.

[0062] (S5) After cleaning the electrophoretic heat sink workpiece with clean water and baking and curing, the workpiece is taken out from the hook of the hanger and the single-sided adhesive insulation paper is removed to obtain a single-sided nano carbon heat sink.

[0063] In step (S2), the single-sided adhesive insulating paper covers the back of the heat sink workpiece and has an easy-to-tear edge. The single-sided adhesive insulating paper is single-sided adhesive-backed insulating paper.

[0064] In step (S3), the hanger is a mechanically assembled hanger, the hanger is made of corrosion-resistant stainless steel 316L, and the hook of the hanger is a spring steel wire hook with a hook tip angle of 45°.

[0065] In step (S3), the degreasing treatment involves using a neutral degreasing agent (Bio-oilclean D3) to remove oil stains from the heat sink workpiece; the water washing and spraying treatment involves spraying the heat sink workpiece with an aqueous solution of a 0.1wt% corrosion inhibitor (siloxane ketone aluminum corrosion inhibitor ac-3s).

[0066] In step (S3), the ultrasonic treatment involves cleaning the heat sink workpiece with pulsed ultrasonic waves in a cleaning solution (citrus-based cleaning agent) at 50°C for 10 minutes; the water rinsing treatment involves rinsing the workpiece with clean water to remove the cleaning solution. The pulsed ultrasonic waves are emitted intermittently at low frequency (25kHz) and high frequency (80kHz).

[0067] In step (S4), the inert material is graphite, the temperature of the electrophoretic deposition bath is 28°C, the initial voltage is 180V, the voltage is 320V after 2 minutes, and the electrophoresis time is 3 minutes.

[0068] In step (S4), the water-based carbon nanomaterial coating comprises the following raw materials in parts by weight:

[0069]

[0070] The method for preparing the waterborne carbon nanotube coating includes mixing waterborne resin, deionized water, dispersant, carbon nanotubes and micron-sized alumina evenly according to the weight parts, and then adding curing agent and mixing evenly to obtain the waterborne carbon nanotube coating.

[0071] The particle size of micron-sized alumina is 1 μm.

[0072] The water-based resin is water-based acrylic resin AC6013, the dispersant is polyvinylpyrrolidone, and the curing agent is Qirun EH 3504.

[0073] In step (S5), the water cleaning process is to remove the electrolyte from the heat sink workpiece with clean water; the baking and curing process is to bake at 80°C for 25 minutes, then at 120°C for 50 minutes, then at 150°C for 50 minutes, and finally cool down to 80°C at a rate of less than 5°C per minute.

[0074] In step (S1), the aluminum alloy is made of aluminum alloy 6063; in step (S5), after the single-sided adhesive insulating paper is removed, the back of the single-sided nano carbon heat sink is aluminum white.

[0075] Example 3

[0076] A method for producing single-sided nano-carbon heat sinks by electrophoresis includes the following steps:

[0077] (S1) Take aluminum alloy and stamp and slice it to obtain heat sink workpiece;

[0078] (S2) Apply single-sided adhesive insulating paper to the back of the heat sink workpiece;

[0079] (S3) Hang multiple heat sink workpieces evenly on the hooks of the hanger, and then perform degreasing, water washing and spraying, ultrasonic treatment and clean water cleaning to obtain pre-treated heat sink workpieces.

[0080] (S4) Using the pretreated heat sink workpiece as the anode, an inert material as the cathode, and water-based carbon nanotube coating as the electrolyte, electrophoretic deposition is performed to obtain the electrophoretic heat sink workpiece.

[0081] (S5) After cleaning the electrophoretic heat sink workpiece with clean water and baking and curing, the workpiece is taken out from the hook of the hanger and the single-sided adhesive insulation paper is removed to obtain a single-sided nano carbon heat sink.

[0082] In step (S2), the single-sided adhesive insulating paper covers the back of the heat sink workpiece and has an easy-to-tear edge. The single-sided adhesive insulating paper is single-sided adhesive-backed insulating paper.

[0083] In step (S3), the hanger is a mechanically assembled hanger, the hanger is made of corrosion-resistant stainless steel 316L, and the hook of the hanger is a spring steel wire hook with a hook tip angle of 45°.

[0084] In step (S3), the degreasing treatment involves using a neutral degreasing agent (Bio-oilclean D3) to remove oil stains from the heat sink workpiece; the water washing and spraying treatment involves spraying the heat sink workpiece with an aqueous solution of a 0.2wt% corrosion inhibitor (siloxane ketone aluminum corrosion inhibitor ac-3s).

[0085] In step (S3), the ultrasonic treatment involves pulsed ultrasonic cleaning for 10 minutes in a cleaning solution (citrus-based cleaning agent) at 70°C; the water rinsing treatment involves rinsing the heat sink workpiece with clean water to remove the cleaning solution. The pulsed ultrasonic waves are emitted intermittently at low frequency (25kHz) and high frequency (80kHz).

[0086] In step (S4), the inert material is graphite, the temperature of the electrophoretic deposition bath is 32°C, the initial voltage is 220V, the voltage is 280V after 1 minute, and the electrophoresis time is 3 minutes.

[0087] In step (S4), the water-based carbon nanomaterial coating comprises the following raw materials in parts by weight:

[0088]

[0089] The method for preparing the waterborne carbon nanotube coating includes mixing waterborne resin, deionized water, dispersant, carbon nanotubes and micron-sized alumina evenly according to the weight parts, and then adding curing agent and mixing evenly to obtain the waterborne carbon nanotube coating.

[0090] The particle size of micron-sized alumina is 10 μm.

[0091] The waterborne resin is silicone-modified waterborne polyurethane SILIKOPUR 8081, the dispersant is polyvinylpyrrolidone, and the curing agent is Qirun EH 3504.

[0092] In step (S5), the water cleaning process is to remove the electrolyte from the heat sink workpiece with clean water; the baking and curing process is to bake at 80°C for 25-35 minutes, then at 120°C for 50-70 minutes, then at 150°C for 40-50 minutes, and finally cool down to 80°C at a rate of less than 5°C per minute.

[0093] In step (S1), the aluminum alloy is made of aluminum alloy 6063; in step (S5), after the single-sided adhesive insulating paper is removed, the back of the single-sided nano carbon heat sink is aluminum white.

[0094] Comparative Example 1

[0095] The difference between this comparative example and Example 1 is as follows:

[0096] In the water-based carbon nanomaterial coating, micron-sized alumina is replaced by a mixture of micron-sized alumina and micron-sized calcium oxide at a mass ratio of 4:6.

[0097] Comparative Example 2

[0098] The difference between this comparative example and Example 1 is as follows:

[0099] A method for producing single-sided nano-carbon heat sinks by electrophoresis includes the following steps:

[0100] (S1) Take aluminum alloy and stamp and slice it to obtain heat sink workpiece;

[0101] (S2) Do not apply stickers to the back of the heat sink component;

[0102] (S3) Hang multiple heat sink workpieces evenly on the hooks of the hanger, and then perform degreasing, water washing and spraying, ultrasonic treatment and clean water cleaning to obtain pre-treated heat sink workpieces.

[0103] (S4) Spray a layer of water-based carbon nanofiber coating onto the pretreated heat sink workpiece to obtain the sprayed heat sink workpiece.

[0104] (S5) After the sprayed heat sink workpiece is cleaned with water and baked to cure, it is taken out from the hook of the hanger to obtain a single-sided nano carbon heat sink.

[0105] Comparative Example 3

[0106] The difference between this comparative example and Example 1 is as follows:

[0107] A method for producing a heat sink includes the following steps:

[0108] (S1) Take aluminum alloy and stamp and slice it to obtain heat sink workpiece;

[0109] (S2) Hang multiple heat sink workpieces evenly on the hooks of the hanger, and then after degreasing, water washing and spraying, ultrasonic treatment, water cleaning and baking curing, the workpieces are taken out from the hooks of the hanger to obtain the heat sink.

[0110] The hanger is a mechanically assembled hanger, the material of which is corrosion-resistant stainless steel 316L, and the hook of which is a spring steel wire hook with a hook tip angle of 45°.

[0111] The degreasing treatment involves using a neutral degreasing agent (Bio-oil clean D3) to remove oil stains from the heat sink workpiece; the water washing and spraying treatment involves spraying the heat sink workpiece with an aqueous solution of a 0.1wt% corrosion inhibitor (siloxane ketone aluminum corrosion inhibitor ac-3s).

[0112] The ultrasonic treatment involves pulsed ultrasonic cleaning for 6 minutes in a cleaning solution (citrus-based cleaning agent) at 60°C; the water rinsing treatment involves rinsing the heat sink workpiece with clean water to remove the cleaning solution. The pulsed ultrasonic waves are emitted intermittently at low frequency (25kHz) and high frequency (80kHz).

[0113] The baking and curing process involves baking at 80℃ for 30 minutes, then at 120℃ for 60 minutes, then at 150℃ for 45 minutes, and finally cooling down to 80℃ at a rate of less than 5℃ per minute.

[0114] Performance testing

[0115] The single-sided nano-carbon heat sink products of Examples 1-3 and Comparative Examples 1-2, as well as the heat sink product of Comparative Example 3, were used to test their coating thickness and heat dissipation effect.

[0116] The testing steps for coating thickness are as follows:

[0117] The maximum and minimum coating thicknesses of the heat sink products were measured using a MikroTest coating thickness gauge, in μm.

[0118] The testing steps for heat dissipation performance are as follows:

[0119] 1) Attach the back of the heat sink product to the surface of the heat source with silicone.

[0120] 2) Use temperature-measuring adhesive to firmly attach the thermocouple to the surface of the heat source;

[0121] 3) Secure the spray fastening agent sensor to ensure it is not loose;

[0122] 4) Record the current ambient temperature T0;

[0123] 5) The entire product is in a normal power-on state;

[0124] 6) Observe the changes in thermocouple data until the data stabilizes, and record the current stable temperature data T;

[0125] 7) Calculate the current temperature rise ΔT as T-T0, and determine whether it meets the design requirement of ΔT being less than 50℃.

[0126] The test records are shown in Table 1 below:

[0127]

[0128] As shown in Table 1 above, the single-sided nano-carbon heat sink produced by electrophoresis in this scheme has a better heat dissipation effect than the heat sink without coating.

[0129] The above embodiments are preferred implementations of the present invention. In addition, the present invention can be implemented in other ways. Any obvious substitutions without departing from the concept of the present invention are within the protection scope of the present invention.

Claims

1. A method for producing single-sided nano-carbon heat sinks by electrophoresis, characterized in that, Includes the following steps: (S1) Take aluminum alloy and stamp and slice it to obtain heat sink workpiece; (S2) Apply single-sided adhesive insulating paper to the back of the heat sink workpiece; (S3) Hang multiple heat sink workpieces evenly on the hooks of the hanger, and then perform degreasing, water washing and spraying, ultrasonic treatment and clean water cleaning to obtain pre-treated heat sink workpieces. (S4) Using the pretreated heat sink workpiece as the anode, an inert material as the cathode, and water-based carbon nanotube coating as the electrolyte, electrophoretic deposition is performed to obtain the electrophoretic heat sink workpiece. (S5) After cleaning the electrophoretic heat sink workpiece with clean water and baking and curing, the workpiece is taken out from the hook of the hanger, and then the single-sided adhesive insulation paper is removed to obtain a single-sided nano carbon heat sink.

2. The method for producing single-sided nano-carbon heat sinks by electrophoresis according to claim 1, characterized in that: In step (S2), the single-sided adhesive insulating paper covers the back of the heat sink workpiece and leaves an easy-to-tear edge.

3. The method for producing single-sided nano-carbon heat sinks by electrophoresis according to claim 1, characterized in that: In step (S3), the hanger is a mechanically assembled hanger, the hanger is made of corrosion-resistant stainless steel 316L, and the hook of the hanger is a spring steel wire hook with a hook tip angle of 45°.

4. The method for producing single-sided nano-carbon heat sinks by electrophoresis according to claim 1, characterized in that: In step (S3), the degreasing treatment involves removing oil stains from the heat sink workpiece using a neutral degreasing agent; the water washing and spraying treatment involves spraying the heat sink workpiece with an aqueous solution of a corrosion inhibitor at a concentration of 0.1wt%-0.2wt%.

5. The method for producing single-sided nano-carbon heat sinks by electrophoresis according to claim 1, characterized in that: In step (S3), the ultrasonic treatment is to clean the heat sink workpiece with pulsed ultrasonic waves in a cleaning solution at 50-70°C for 5-10 minutes; the water rinsing treatment is to remove the cleaning solution from the heat sink workpiece with clean water.

6. The method for producing single-sided nano-carbon heat sinks by electrophoresis according to claim 1, characterized in that: In step (S4), the inert material is graphite or stainless steel, the temperature of the electrophoretic deposition bath is 28-32℃, the initial voltage is 180-220V, the voltage is 280-320V after 1-2 minutes, and the electrophoresis time is 2.5-3 minutes.

7. The method for producing single-sided nano-carbon heat sinks by electrophoresis according to claim 1, characterized in that: In step (S4), the water-based carbon nanomaterial coating comprises the following raw materials in parts by weight:

8. The method for producing single-sided nano-carbon heat sinks by electrophoresis according to claim 7, characterized in that: The waterborne resin is a waterborne acrylic resin or an organosilicon-modified waterborne polyurethane, the dispersant is polyvinylpyrrolidone, and the curing agent is Qirun EH 3504 and / or polyetheramine curing agent T-5000.

9. The method for producing single-sided nano-carbon heat sinks by electrophoresis according to claim 1, characterized in that: In step (S5), the water cleaning process involves using clean water to remove the electrolyte from the heat sink workpiece. The baking and curing process involves baking at 80±3℃ for 25-35 minutes, then at 120±3℃ for 50-70 minutes, then at 150±3℃ for 40-50 minutes, and finally cooling down to 80℃ at a rate of less than 5℃ per minute.

10. The method for producing single-sided nano-carbon heat sinks by electrophoresis according to claim 1, characterized in that: In step (S1), the aluminum alloy is made of aluminum alloy 6063; in step (S5), after the single-sided adhesive insulating paper is removed, the back of the single-sided nano carbon heat sink is aluminum white.

Images