A preparation method and application of copper-diamond-coated copper layer grafted fin

Abstract

The application discloses a preparation method and application of copper-diamond copper-coated layer grafted fin, and relates to the technical field of heat dissipation material manufacturing. The preparation method comprises the following steps: pretreating a copper-diamond bottom plate; laying a pure copper layer on the surface of the bottom plate; forming a dense pure copper coating layer on the surface of the copper-diamond bottom plate through hot-pressing sintering; performing surface treatment on the pure copper coating layer to obtain a copper-diamond bottom plate with a copper coating layer; positioning and clamping the copper-diamond bottom plate with the copper coating layer to a laser printing substrate; directly printing a fin structure on the pure copper coating layer by using a laser selective melting technology; and obtaining a finished product after cooling and demolding. In the application, the pure copper coating layer is used as a laser absorption transition layer, laser penetration is effectively blocked, diamond ablation and graphitization are avoided, interface defects are reduced, and the bonding strength of the fin and the substrate is improved; meanwhile, the process flow is simplified, the production cost is reduced, the design freedom of the fin structure is widened, and high-precision, high-reliability and high-efficiency manufacturing of a copper-diamond liquid cooling heat dissipation component is realized.

Description

Technical Field

[0001] This application relates to the field of heat dissipation material manufacturing technology, and in particular to a method for preparing and applying copper diamond copper-clad fin grafted with copper. Background Technology

[0002] With the rapid development of high-power chips, third-generation semiconductor devices, laser equipment, data center servers, and new energy power control equipment towards higher power density, miniaturization, and integration, heat flux density continues to rise. This places increasingly higher demands on the thermal conductivity, thermal expansion matching, structural precision, and long-term reliability of heat dissipation components. Copper-diamond composite materials, due to their ultra-high thermal conductivity, low coefficient of thermal expansion, and good thermal stability, have become the preferred material for solving the heat dissipation bottleneck of high heat flux density, and their application demand in the field of high-end thermal management continues to increase.

[0003] Copper-diamond composites, using high thermal conductivity diamond as the reinforcing phase and copper or copper alloys as the matrix, exhibit a theoretical thermal conductivity exceeding 1000 W / (m·K), significantly superior to conventional heat dissipation materials such as pure copper, tungsten copper, and molybdenum copper. Their coefficient of thermal expansion can be controlled through composition and structure, achieving better thermal expansion matching with silicon, SiC chips, and ceramic substrates. This helps reduce thermal cycling stress and improve the operational stability of devices under alternating temperature conditions. Furthermore, this material possesses good dimensional stability and resistance to thermal fatigue, making it suitable for long-term use in high-temperature and complex stress environments, demonstrating significant application potential in high-end electronic packaging and liquid-cooled heat dissipation components.

[0004] Copper-diamond composites have high hardness, relatively high brittleness, and strong wear resistance. However, directly using traditional machining methods such as chiseling, milling, and CNC (Computer Numerical Control) cutting to form fins results in rapid tool wear. Machining complex fin structures with thin walls, high density, and high aspect ratios is difficult, easily leading to problems such as fin chipping, breakage, and large dimensional deviations, making it difficult to directly produce fin structures that meet the requirements of high-performance liquid cooling. To improve machinability, a process route combining SPS (Solid Phase Synthesis) copper plating with chiseling is adopted. First, a pure copper plating layer is prepared on the copper-diamond surface, and then the plating layer is chiseled. However, this route usually requires custom-made SPS molds, which are costly and have a long preparation cycle, making it difficult to form complex microchannel and high-density thin-walled fin structures.

[0005] Laser additive manufacturing (grafting printing) technology enables moldless freeform forming, making it suitable for fabricating complex fins and microchannel structures, and has become an important technological direction to replace machining. However, the infrared lasers used for dense copper alloys have high energy and easily penetrate the matrix. Under the action of high-energy lasers, the diamond phase is prone to ablation and graphitization. When directly grafting and printing fins onto the copper diamond matrix, problems such as excessive slag formation, porosity and incomplete fusion defects at the interface, and low bonding strength are likely to occur. The fins are at risk of delamination and detachment, and it is difficult to ensure the consistency of forming and the stability of batch production, making it difficult to meet the long-term use requirements of high-end liquid cooling components. Summary of the Invention

[0006] The main purpose of this application is to provide a method for preparing copper-diamond copper-clad grafted fins and its application, aiming to solve the problems of severe slag formation, interface porosity and incomplete fusion defects, and low interface bonding strength when directly laser grafting and printing fins on the copper-diamond body.

[0007] To achieve the above objectives, this application provides a method for preparing copper-diamond copper-clad fins, comprising the following steps: Pre-treat the copper diamond base plate to remove surface oil, oxide layer and impurities; A pure copper layer is laid on the surface of the pretreated copper-diamond base plate; The copper diamond base plate after the pure copper layer is laid is hot-pressed and sintered to form a dense pure copper cladding on the surface of the copper diamond base plate. The pure copper cladding after hot pressing and sintering is subjected to surface treatment, which includes surface grinding and sandblasting roughening, to obtain a copper-diamond base plate with copper cladding. A positioning groove matching the external dimensions of the copper-clad copper diamond base plate is processed on the laser printing substrate, and the copper-clad copper diamond base plate is embedded in the positioning groove. The laser selective melting technology is used to directly print fin structures on a pure copper cladding layer. The laser energy is absorbed by the pure copper cladding layer and avoids penetrating to the copper diamond substrate. After printing, the material is cooled and demolded to obtain copper-diamond copper-coated grafted fins.

[0008] Optionally, the pretreatment includes grinding, cleaning, and drying to achieve a smooth and clean surface on the copper diamond base plate.

[0009] Optionally, the pure copper layer is a pure copper foil or a pure copper powder layer, and the pure copper layer uniformly covers the bonding surface of the copper diamond substrate.

[0010] Optionally, the hot pressing sintering process parameters are: sintering temperature of 800℃-1050℃, sintering pressure of 10MPa-40MPa, holding time of 10min-60min, and sintering atmosphere of vacuum or protective atmosphere.

[0011] Optionally, the thickness of the pure copper cladding is 0.2mm-1.5mm.

[0012] Optionally, the surface grinding makes the flatness of the pure copper cladding surface ≤0.05mm; the sandblasting roughening uses copper alloy abrasive particles and the sandblasting pressure is 0.3MPa-0.6MPa.

[0013] Optionally, the depth of the positioning groove is 2mm-5mm.

[0014] Optionally, when using laser selective melting technology to directly print fin structures on pure copper cladding, the process parameters are as follows: laser power of 300W-700W, scanning speed of 800mm / s-1300mm / s, layer thickness of 20μm-50μm, scanning spacing of 0.06mm-0.10mm, printing powder of pure copper powder or copper alloy powder, and the particle size of the printing powder of 15μm-50μm; the first layer uses remelting scanning to strengthen the interface bonding.

[0015] In addition, to achieve the above objectives, this application also provides an application of the copper-diamond copper-clad grafted fin prepared by the above-described method for preparing copper-diamond copper-clad grafted fins in high heat flux density heat dissipation components.

[0016] Optionally, the high heat flux density heat dissipation component includes a high-power chip heat sink, a third-generation semiconductor device heat sink, a laser equipment heat sink, a data center server liquid cooling heat sink, or a new energy electronic control heat sink.

[0017] Compared with the prior art, this application has the following beneficial effects: (1) This application adopts a process route that combines hot pressing sintering copper plating with laser grafting printing, replacing the complex process of traditional SPS copper plating followed by tooth removal. Hot pressing sintering does not require customized special molds, which can significantly shorten the mold design and manufacturing cycle and reduce production costs. Laser printing realizes one-time forming of fin structure, avoiding multiple machining processes, and improving production efficiency by more than 50%, which is particularly suitable for multi-variety, small-batch, and rapid iteration production mode.

[0018] (2) The laser selective melting technology used in this application has the characteristics of being moldless and free to form, and can conveniently prepare thin-walled, high-density, high aspect ratio, and complex tortuous microchannel fin structures, breaking through the structural limitations of traditional tooth-scraping processes. The minimum wall thickness of the fins can reach 0.2 mm, which can meet the design requirements of high-end liquid cooling heat dissipation components for complex flow channel structures and significantly improve heat dissipation performance.

[0019] (3) This application uses a pure copper cladding as a laser absorption transition layer, which effectively blocks the transmission of high-energy laser to the copper diamond core, inhibiting the ablation and graphitization of the diamond phase from the source, and reducing defects such as interface slag, pores, and inclusions. The fins and the copper cladding achieve a metallurgical bond of the same material, increasing the interface bonding strength by more than 30%, avoiding failure modes such as delamination and peeling, and ensuring the service stability of the liquid cooling components under long-term thermal cycling conditions. Attached Figure Description

[0020] Figure 1 This is a flowchart illustrating the preparation method of copper-diamond copper-clad fin grafted onto the embodiments of this application. Detailed Implementation

[0021] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0022] Reference Figure 1 This application provides a method for preparing copper-diamond copper-clad grafted fins, comprising the following steps: S1. Pre-treat the copper diamond base plate to remove surface oil, oxide layer and impurities.

[0023] During processing, storage, and transportation, copper-diamond base plates are highly susceptible to the adhesion of oil, dust, and metal debris. A thin oxide layer also forms spontaneously. These impurities directly lead to poor adhesion of the subsequent copper cladding layer, causing defects such as delamination, porosity, and insufficient bonding. Therefore, pretreatment is necessary to achieve surface cleaning and smoothing.

[0024] S2. Lay a pure copper layer on the surface of the pretreated copper diamond base plate.

[0025] A pure copper layer is laid on the surface of the pretreated copper-diamond substrate to create a homogeneous and complete pure copper transition buffer layer, protecting the diamond substrate and adapting to the laser printing process. Unlike traditional partial coating processes, this step uses a full-coverage laying method to avoid exposing the substrate.

[0026] S3. Hot pressing and sintering are performed on the copper diamond base plate after the pure copper layer is laid to form a dense pure copper cladding on the surface of the copper diamond base plate.

[0027] The loose, laid-out pure copper layer is transformed into a dense, high-strength, and integrated pure copper cladding through a high-temperature, high-pressure sintering process. This achieves a metallurgical bond between the pure copper layer and the copper-diamond matrix, thus solving the problems of loose copper layers, easy detachment, and high porosity. Copper foil and copper powder laid at room temperature are only physically bonded, with large interfacial gaps and extremely poor adhesion, which cannot meet the requirements of laser printing and long-term heat dissipation. Hot-pressing sintering is necessary to achieve interface strengthening and structural densification.

[0028] S4. Surface treatment is performed on the pure copper cladding after hot pressing and sintering. The surface treatment includes surface grinding and sandblasting roughening to obtain the copper-coated copper diamond base plate.

[0029] Surface grinding is mainly used to correct slight deformation, surface protrusion and flatness deviation of the copper clad layer after hot pressing and sintering. It controls the flatness of the clad layer surface within 0.05mm, ensuring uniform powder spreading and stable laser focal length in subsequent selective laser melting. It effectively avoids problems such as fin size deviation, poor local melting and poor forming consistency caused by uneven surface.

[0030] Sandblasting roughening involves uniformly sandblasting the surface of the copper-clad layer to create a uniform microscopic rough structure. This treatment method avoids introducing foreign impurities that contaminate the interface and significantly increases the specific surface area of ​​the clad layer. The molten copper powder subsequently laser-printed can be fully embedded in the microscopic rough structure, forming a composite bonding mechanism that combines mechanical interlocking and metallurgical bonding. This greatly improves the bonding strength and thermal fatigue resistance between the fins and the copper-clad layer, resulting in a qualified copper-diamond base plate with a copper-clad layer.

[0031] S5. Process a positioning groove on the laser printing substrate that matches the outer dimensions of the copper-clad copper diamond base plate, and embed the copper-clad copper diamond base plate into the positioning groove.

[0032] Positioning grooves that perfectly match the workpiece's dimensions are machined on the laser printing substrate. The depth of these grooves can be controlled between 2mm and 5mm. This depth ensures the workpiece is fully embedded and stably positioned, preventing it from wobbling or tilting due to insufficient depth, or interfering with powder spreading and the laser path due to excessive depth. A copper-clad diamond base plate is then fully embedded within the positioning grooves, relying on a mechanical limiting structure to achieve zero offset and zero vibration throughout the process. This ensures consistent printing position for each batch of workpieces, improving product dimensional consistency and batch production stability.

[0033] S6. Using laser selective melting technology, fin structures are directly printed on pure copper cladding. The laser energy is absorbed by the pure copper cladding, thus avoiding penetration to the copper diamond substrate.

[0034] In traditional laser printing processes where high-energy lasers directly ablate and graphitize the diamond phase on a copper-diamond substrate, a large number of defects such as slag formation, porosity, and lack of fusion are generated. This step utilizes the characteristic of pure copper cladding preferentially absorbing laser energy, which can prevent the laser from penetrating and damaging the copper-diamond substrate, thus solving the substrate failure problem at its root.

[0035] S7. After printing, cool and demold to obtain copper diamond copper-coated fins.

[0036] After printing, cooling and demolding are performed to eliminate residual thermal stress after printing, ensuring the structural integrity and dimensional stability of the product. During laser selective melting, the workpiece undergoes rapid high-temperature melting in localized areas, generating uneven thermal stress inside. Rapid cooling can easily lead to problems such as microcracks in the fins, interface cracking, and structural deformation.

[0037] In other embodiments, the pretreatment includes grinding, cleaning, and drying processes to bring the surface of the copper diamond substrate to a smooth and clean state.

[0038] Precision grinding can remove tool marks, burrs, and loose surface structures from the base plate, correcting surface flatness; a composite cleaning method combining organic solvents and ultrasonic cleaning can remove surface oil, particulate impurities, and oxide layers; vacuum drying can remove adsorbed moisture from the substrate surface, preventing moisture vaporization and pore defects during subsequent high-temperature sintering, ultimately obtaining a copper diamond substrate surface that is free of impurities, free of oxidation, and flat and uniform.

[0039] In other embodiments, the pure copper layer is a pure copper foil or a pure copper powder layer, which uniformly covers the bonding surface of the copper diamond substrate.

[0040] The pure copper layer can be made from either high-purity copper foil or high-purity copper powder, allowing for flexible selection based on the substrate structure and fin forming requirements. Copper foil is suitable for conventional flat substrates, offering uniform thickness, stable operation, and good consistency. Copper powder is suitable for irregularly shaped substrates with microstructures, precisely filling minute depressions and achieving higher bonding accuracy. The laying process strictly ensures that the pure copper layer completely covers all laser-printed areas of the base plate, with uniform thickness, no gaps, and no wrinkles, forming a continuous and complete copper transition layer. This provides structural protection for subsequent laser energy isolation and homogeneous metallurgical bonding.

[0041] In other embodiments, the hot-pressing sintering process parameters are: sintering temperature of 800℃-1050℃, sintering pressure of 10MPa-40MPa, holding time of 10min-60min, and sintering atmosphere of vacuum or protective atmosphere. The thickness of the pure copper cladding can be 0.2mm-1.5mm.

[0042] The sintering atmosphere can employ a vacuum or inert protective atmosphere to prevent oxidation and deterioration of pure copper at high temperatures. A sintering temperature of 800℃-1050℃ allows for the recrystallization and particle fusion of pure copper, ensuring a dense, non-porous copper layer. Combined with an axial sintering pressure of 10MPa-40MPa, interfacial gaps and air are forcibly expelled, promoting the interdiffusion of copper atoms with the substrate surface atoms, forming a stable metallurgical bonding interface. An adjustable holding time of 10min-60min can accommodate densification requirements for different coating thicknesses. Finally, a dense pure copper coating with a thickness of 0.2mm-1.5mm is formed on the surface of the copper-diamond substrate. This coating structure is stable and firmly bonded, completely isolating subsequent laser energy without affecting the overall heat dissipation performance of the substrate.

[0043] In other embodiments, surface grinding achieves a surface flatness of ≤0.05mm for the pure copper cladding; sandblasting roughening uses copper alloy abrasive particles at a pressure of 0.3MPa-0.6MPa.

[0044] This embodiment controls the flatness of the pure copper cladding surface to within 0.05mm, which ensures that the overall base surface of the copper cladding layer is uniform in height and the surface is flat and uniform. This ensures that the powder thickness of each layer is consistent and the laser energy is applied evenly during the printing process, effectively guaranteeing the dimensional accuracy and structural consistency of the high-density thin-walled fins and high aspect ratio microchannels, while eliminating local stress concentration defects caused by uneven base surface.

[0045] For sandblasting roughening, copper alloy abrasive particles are preferred, with the sandblasting pressure controlled between 0.3 MPa and 0.6 MPa. This parameter range represents the optimal process window for pure copper cladding materials, exhibiting strong process adaptability and stability. Using copper alloy abrasive particles instead of conventional abrasives such as quartz sand or steel grit completely avoids the embedding of dissimilar hard particles into the cladding surface, preventing inclusions and contamination. This eliminates hard inclusions, pores, and incomplete fusion defects at the printing interface, ensuring the purity of the copper cladding material. It also achieves a homogeneous metallurgical bond between the copper printed fins and the copper cladding, further enhancing the interface bonding strength and the heat dissipation stability of the finished product.

[0046] In other embodiments, when using laser selective melting technology to directly print fin structures on pure copper cladding, the process parameters are as follows: laser power of 300W-700W, scanning speed of 800mm / s-1300mm / s, layer thickness of 20μm-50μm, scanning spacing of 0.06mm-0.10mm, printing powder of pure copper powder or copper alloy powder, and particle size of printing powder of 15μm-50μm; the first layer uses remelting scanning to strengthen the interface bonding.

[0047] This embodiment employs refined laser selective melting parameters matched to the forming characteristics of pure copper, using 15μm-50μm pure copper or copper alloy powder, coupled with 300W-700W laser power, 800mm / s-1300mm / s scanning speed, 20μm-50μm layer thickness, and 0.06mm-0.10mm scanning spacing to ensure full melting of the copper powder and continuous, dense forming. Simultaneously, the first layer utilizes a remelting scanning process to perform secondary melting and strengthening of the interface, completely eliminating fine pores and gaps at the interface, achieving an integrated metallurgical bond between the printed fins and the pure copper coating. This allows for the stable forming of complex fin and microchannel structures with thin walls, high density, and high aspect ratio.

[0048] The copper-diamond copper-clad grafted fins obtained by the above-described method can be used in high heat flux density heat dissipation components.

[0049] This application simultaneously protects specific application scenarios for the copper-diamond copper-clad fins obtained by the above-mentioned preparation method. This composite fin product integrates the dual core advantages of copper-diamond composite materials and laser-printed copper fins, perfectly adapting to high-end heat dissipation conditions with high heat flux density, alternating temperature cycling, long-term continuous service, and high reliability requirements. The copper-diamond matrix possesses ultra-high thermal conductivity, low coefficient of thermal expansion, excellent thermal stability, and resistance to thermal fatigue, effectively matching the thermal expansion characteristics of semiconductors, chips, and other devices, and reducing thermal cycling stress damage. The copper precision fins grafted onto the surface feature high structural precision, large heat dissipation specific surface area, and dense, defect-free interface bonding, completely solving the problems of traditional copper-diamond heat dissipation components being difficult to form, prone to failure, and limited in heat dissipation efficiency. It can be widely used in various high-end, high-heat-flux-density heat dissipation components.

[0050] In other embodiments, the high heat flux density heat dissipation component includes a high-power chip heat sink, a third-generation semiconductor device heat sink, a laser equipment heat sink, a data center server liquid cooling heat sink, or a new energy electronic control heat sink.

[0051] In other preferred embodiments of this application, five typical high-end, high-heat-flux-density heat dissipation application scenarios are specifically defined, and the adaptation characteristics and application advantages of each scenario are described in detail below: First, applications in high-power chip heat sinks. High-power computing chips and power chips operate with high heat flux density and concentrated heat generation, and are subject to high-frequency temperature alternation conditions for extended periods. Traditional heat sinks are prone to problems such as thermal expansion mismatch, delayed heat dissipation, and fatigue failure. This product utilizes an ultra-high thermal conductivity substrate to rapidly dissipate the concentrated heat source from the chip, and matches it with precision high-density fins to achieve rapid convection heat dissipation. At the same time, its low thermal expansion characteristics effectively buffer the thermal stress at the chip-heat sink interface, ensuring long-term stable operation of the chip.

[0052] Secondly, applications in heat sinks for third-generation semiconductor devices. Third-generation semiconductor devices such as SiC and GaN operate at high frequencies, high voltages, and high temperatures, under harsh conditions, placing extremely high demands on the heat dissipation components' high-temperature resistance, thermal matching, and structural reliability. This product is free from interface delamination and peeling defects, exhibits excellent thermal stability, and is suitable for the continuous high-temperature operating environment of semiconductor devices. It precisely controls the device's junction temperature, preventing performance degradation and device damage caused by overheating.

[0053] Third, applications in laser equipment heat sinks. During operation, laser equipment experiences high instantaneous peak heat flux density and extremely concentrated heat. Inadequate heat dissipation can easily lead to laser module misalignment, power attenuation, and shortened lifespan. This grafted fin features high thermal conductivity and sensitive heat dissipation response, quickly channeling the instantaneous high heat flux in the core heating area of ​​the laser. Simultaneously, the high-precision molded fin structure adapts to the compact and integrated structural design requirements of laser equipment, meeting the high-end heat dissipation needs of precision laser devices.

[0054] Fourth, applications of liquid cooling radiators for data center servers. With the continuous upgrading of server computing power and the significant increase in heat flux density per unit, traditional air cooling can no longer meet the cooling demands, making liquid cooling a core development direction. This product features a dense fin structure and high dimensional accuracy, adaptable to complex liquid cooling microchannel structures. It is resistant to liquid cooling medium erosion, thermal fatigue, and long-term service without detachment, stably adapting to the high-load, uninterrupted liquid cooling conditions of servers, effectively reducing server energy consumption and the probability of high-temperature failures.

[0055] Fifth, application of radiators for new energy vehicle electronic control systems. The operating conditions of components such as electronic control systems and motor controllers in new energy vehicles are complex, characterized by frequent start-stop cycles, temperature fluctuations, and vibration and shock. This places stringent requirements on the bonding strength, structural stability, and heat dissipation uniformity of the radiator. This product features high interface bonding strength, vibration resistance, and resistance to thermal cycling fatigue. It can effectively adapt to the complex service environment of new energy vehicle electronic control systems, quickly and evenly dissipating heat from the electronic control modules, preventing performance failures caused by localized overheating, and improving the operational stability of the entire new energy vehicle control system.

[0056] The above five application scenarios all belong to the high-end thermal management field with high heat flux density and high reliability requirements. They can give full play to the material performance advantages and structural forming advantages of the copper diamond copper-clad fin grafted by the present invention. Compared with traditional heat dissipation components, they have the characteristics of higher heat dissipation efficiency, longer service life, stronger structural adaptability and better working stability, and have extremely high industrial application value.

[0057] The technical solution of this application will be further described below with reference to specific embodiments.

[0058] Example 1 This embodiment provides a method for preparing copper-diamond copper-clad grafted fins, the specific steps of which are as follows: Step 1: Pre-treatment of copper-diamond base plate A copper-diamond composite preform with a diamond volume fraction of 55% and a pure copper matrix was selected. The preform was machined to a size of 150mm × 100mm × 10mm by wire cutting. The surface to be sintered was then precision ground to a surface roughness controlled within Ra 1.6μm. Subsequently, it was ultrasonically cleaned for 15 minutes each with acetone and anhydrous ethanol to remove surface oil and impurities. Finally, it was dried in a vacuum drying oven at 80℃ for 2 hours to ensure complete surface cleanliness.

[0059] Step 2: Copper Layer Laying Take 99.95% pure copper foil with a thickness of 0.5 mm and cut it to the same size as the surface of the copper-diamond substrate to be sintered. Tightly adhere the pure copper foil to the surface of the pretreated copper-diamond substrate, ensuring no air bubbles or wrinkles and completely covering the area to be sintered.

[0060] Step 3: Hot pressing and sintering to prepare the copper-clad layer The copper-diamond base plate with copper foil was placed in a vacuum hot-pressing sintering furnace, and a vacuum of 1×10⁻⁶ was applied. -2 Below Pa. The temperature was raised to 950℃ at a rate of 10℃ / min, and a pressure of 30MPa was applied, holding for 30 minutes. After holding, the furnace was cooled to below 200℃, and the pressure was released before removal. Testing revealed a pure copper coating thickness of 0.45mm, with a dense bond between the coating and the substrate and no obvious interface defects.

[0061] Step 4: Surface treatment of copper cladding layer The hot-pressed sintered pure copper cladding was surface-ground using an 80# white corundum grinding wheel to a depth of 0.02 mm until the flatness reached 0.03 mm. Subsequently, sandblasting was performed to roughen the surface using 80-mesh copper alloy particles at a pressure of 0.4 MPa, a distance of 100 mm, and a time of 30 seconds, resulting in a uniform rough structure and a surface roughness of Ra 6.3 μm.

[0062] Step 5: Positioning and clamping the printing substrate A positioning groove measuring 150.2mm × 100.2mm × 3mm was machined on a 304 stainless steel laser printing substrate, with a groove bottom flatness of 0.02mm. A copper-diamond base plate with a surface-treated copper clad laminate was embedded into the groove, achieving tight fit positioning with an interference fit of 0.1mm, without the need for additional fixing devices.

[0063] Step Six: Laser Grafting of Printed Fins Selective Laser Melting (SLM) equipment was used, employing pure copper powder with a particle size of 45μm as the printing material. The laser printing process parameters were set as follows: laser power of 500W, scanning speed of 1000mm / s, layer thickness of 30μm, scanning spacing of 0.08mm, a checkerboard scanning strategy, and a rotation angle of 67°. The first layer used remelting scanning with a remelting power of 300W and a scanning speed of 600mm / s. The printed fins had a height of 5mm, a thickness of 0.5mm, and a spacing of 1.5mm, resulting in a total of 100 parallel fins.

[0064] During the printing process, the laser energy is fully absorbed by the pure copper coating, and the surface temperature of the coating reaches above the melting point of copper, forming a molten pool. Due to the blocking effect of the pure copper coating, the laser energy does not penetrate to the copper diamond core, and the core temperature remains below 300℃, effectively preventing the ablation and graphitization of the diamond.

[0065] Step 7: Cooling, Demolding, and Post-processing After printing, the workpiece is cooled to room temperature in the furnace, with inert gas protection maintained during the cooling process. The workpiece is then removed directly from the positioning groove, a small amount of support structure is removed, and the edges of the fins are slightly deburred to obtain a complete copper-diamond copper-clad laminated fin liquid cooling heat dissipation component.

[0066] Example 2 This embodiment is basically the same as embodiment 1, except that: In step three, the hot-pressing sintering process parameters were adjusted to: sintering temperature of 850℃, sintering pressure of 20MPa, and holding time of 45 minutes. The resulting pure copper cladding thickness was 0.6mm.

[0067] In step six, the laser printing process parameters are adjusted as follows: laser power of 400W, scanning speed of 1200mm / s, layer thickness of 25μm, and scanning spacing of 0.07mm. The printed fin structure is wavy, with a peak height of 3mm, a trough depth of 2mm, and a wavelength of 6mm.

[0068] Example 3 This embodiment is basically the same as embodiment 1, except that: In step two, pure copper powder is used for laying, with a particle size of 200 mesh and a laying thickness of 0.8 mm.

[0069] The hot-pressing sintering process parameters in step three are: sintering temperature of 1050℃, sintering pressure of 40MPa, and holding time of 15 minutes. The resulting pure copper cladding thickness is 0.7mm.

[0070] In step six, the printed fins are a grid structure with a grid line width of 0.3mm, a grid aperture of 2mm×2mm, and a grid height of 4mm.

[0071] Comparative Example 1 This comparative example uses the traditional SPS copper-clad post-removal tooth process: A copper-diamond substrate of the same specifications as in Example 1 was used. A 0.5 mm thick pure copper cladding was prepared on the surface of the copper-diamond substrate using the SPS process. The SPS process parameters were: temperature 950℃, pressure 30 MPa, and holding time 10 minutes. Subsequently, the pure copper cladding was machined by tooth removal. The tooth removal tool was made of high-speed steel, the tool rotation speed was 3000 rpm, the feed rate was 0.1 mm / r, and the depth of cut was 0.5 mm, thus producing a fin structure of the same specifications as in Example 1.

[0072] The following problems occurred during the processing: the cutting tools wore out severely and needed to be replaced after processing 20 fins; slight chipping occurred at the edges of the fins; the processing time was about three times that of laser printing; and due to limitations in the tooth-scraping process, it was impossible to process fins with complex structures.

[0073] Comparative Example 2 This comparative example uses laser-printed fins directly onto the copper-diamond substrate: A copper-diamond substrate of the same specifications as in Example 1 was used. Without copper plating, the substrate underwent surface grinding and sandblasting before laser printing. The laser printing process parameters were exactly the same as in Example 1.

[0074] The following problems occurred during the printing process: the laser penetrated into the copper diamond core, the local temperature of the core exceeded 800°C, and the diamond underwent significant ablation and graphitization; a large amount of slag and pores were generated at the interface, with the slag depth reaching 0.3 mm; the bonding strength between the fins and the substrate was low, with a shear strength of only 15 MPa; the molding quality was unstable, and the scrap rate reached 35%.

[0075] Performance comparison test The performance of the samples prepared in Examples 1-3 and Comparative Examples 1-2 was tested, and the results are shown in Table 1: Table 1

[0076] The test results show that: The fin dimensional accuracy and surface roughness of Examples 1-3 of this application are significantly better than those of Comparative Examples 1-2, indicating that the laser printing process has higher forming accuracy and better surface roughness.

[0077] Regarding the interface bonding strength, the interface bonding strength of Examples 1-3 is significantly higher than that of Comparative Example 2, indicating that the pure copper cladding effectively improves the interface quality as a transition layer.

[0078] Regarding the interface defect rate, the defect rates of Examples 1-3 are much lower than those of Comparative Example 2, indicating that this application effectively suppresses the ablation and slag formation problems caused by laser penetration.

[0079] In terms of production efficiency, the production cycle of Examples 1-3 is significantly shorter than that of Comparative Example 1, indicating that the process flow of this application is simplified and the production efficiency is significantly improved.

[0080] In terms of material utilization, the material utilization of Examples 1-3 is much higher than that of Comparative Example 1, indicating that laser printing, as an additive manufacturing technology, has the advantage of high material utilization.

[0081] Example 4 This embodiment provides a method for preparing a copper-diamond copper-clad laminated fin liquid cooling heat dissipation component, the specific steps of which are as follows: Step 1: Pre-treatment of copper-diamond base plate A copper-diamond composite preform with a diamond volume fraction of 45% and a copper-chromium alloy matrix (Cr content 0.6%) was selected. The copper-diamond composite preform was machined to a size of 200mm × 150mm × 8mm. The surface to be sintered was ground to a surface roughness controlled within Ra 2.0μm. Chemical cleaning with an alkaline cleaning agent was performed to remove surface oil, followed by rinsing with deionized water and drying in a 60℃ hot air drying oven for 1 hour.

[0082] Step 2: Copper Layer Laying Electrolytic copper powder with a purity of 99.9% and a particle size of 200 mesh was used to lay a 1.0 mm thick layer on the surface of the pretreated copper-diamond substrate. A special scraper was used during the laying process to ensure that the powder was evenly and evenly distributed. After compaction, the powder layer thickness was 0.8 mm.

[0083] Step 3: Hot pressing and sintering to prepare the copper-clad layer The copper-diamond base plate coated with copper powder was placed in an argon-protected hot-press sintering furnace at a flow rate of 2 L / min. The temperature was raised to 900℃ at a rate of 15℃ / min, a pressure of 25 MPa was applied, and the temperature was held for 40 minutes. After holding, the temperature was cooled to below 400℃ at a rate of 5℃ / min, and then cooled to room temperature with the furnace. Testing showed that the pure copper coating thickness was 0.65 mm, and the coating density reached 99.2%.

[0084] Step 4: Surface treatment of copper cladding layer The hot-pressed sintered pure copper cladding was surface-ground using a 120# silicon carbide grinding wheel at a depth of 0.01 mm in two passes, achieving a final flatness of 0.02 mm. Subsequently, sandblasting was performed to roughen the surface using 100-mesh alumina particles at a pressure of 0.5 MPa, a distance of 80 mm, and a time of 20 seconds, resulting in a uniformly rough surface structure with a surface roughness of Ra 5.0 μm.

[0085] Step 5: Positioning and clamping the printing substrate A positioning groove measuring 200.1mm × 150.1mm × 4mm was machined on an aluminum alloy laser printing substrate, with vacuum adsorption holes at the bottom of the groove. A copper-diamond base plate with a surface-treated copper clad laminate was embedded into the groove, and mechanical positioning was achieved through an interference fit of 0.05mm, while vacuum adsorption was activated to assist in fixation.

[0086] Step Six: Laser Grafting of Printed Fins Laser selective melting was used, employing copper-chromium alloy powder as the printing material. The powder composition was Cu-0.6Cr, and the particle size was 15μm. Laser printing process parameters were set as follows: laser power 600W, scanning speed 1100mm / s, layer thickness 40μm, scanning spacing 0.09mm, using a strip scanning strategy, and a rotation angle of 90°. The first layer used remelting scanning with a remelting power of 400W and a scanning speed of 800mm / s. The printed fins had a height of 8mm, a thickness of 0.8mm, a fin spacing of 2.0mm, and a staggered fin structure, with a total of 150 fins printed.

[0087] During printing, the molten pool status is monitored in real time through an online monitoring system to ensure print quality. The pure copper coating effectively absorbs laser energy, resulting in a stable molten pool with no spatter or smoke.

[0088] Step 7: Cooling, Demolding, and Post-processing After printing, the workpiece is cooled to below 150°C in the furnace under argon protection. Vacuum adsorption is then turned off, and the workpiece is removed from the positioning groove. The printing support structure is removed, and the fins undergo vibration finishing to remove burrs and improve surface quality. Finally, a complete copper-diamond coated copper-plated finned liquid cooling heat dissipation component is obtained.

[0089] Performance test results show that the thermal conductivity of the heat dissipation component reaches 650W / (m·K), the interfacial bonding strength reaches 48MPa, and it can operate stably for 1000 hours without failure under a heat flux density of 300W / cm².

[0090] Example 5 This embodiment provides a method for preparing copper-diamond copper-clad copper-coated fins for liquid cooling of data center servers. A copper-diamond composite material preform is selected, with a diamond volume fraction of 60% and dimensions of 300mm × 200mm × 12mm. The preparation follows the process flow of Example 1, with the following differences: In step three, the hot pressing sintering temperature is 1000℃, the pressure is 35MPa, and the holding time is 25 minutes to obtain a pure copper coating with a thickness of 1.2mm.

[0091] In step six, the printed fins are microchannel structures with a channel width of 0.3 mm, a channel depth of 1.5 mm, and a channel spacing of 0.5 mm, forming a complex microfluidic network. The laser printing parameters are: laser power 350 W, scanning speed 900 mm / s, layer thickness 20 μm, and scanning spacing 0.06 mm.

[0092] This microchannel heatsink is used for cooling a certain type of server CPU. Under the condition of heat flux density of 150W / cm², the heatsink has a thermal resistance of 0.12℃ / W and a voltage drop of 8kPa. The heat dissipation efficiency is 35% higher than that of traditional copper heatsinks, and the energy consumption is reduced by 20%.

[0093] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A method for preparing copper-diamond copper-clad fins, characterized in that, Includes the following steps: Pre-treat the copper diamond base plate to remove surface oil, oxide layer and impurities; A pure copper layer is laid on the surface of the pretreated copper-diamond base plate; The copper diamond base plate after the pure copper layer is laid is hot-pressed and sintered to form a dense pure copper cladding on the surface of the copper diamond base plate. The thickness of the pure copper cladding is 0.2mm-1.5mm; The pure copper cladding after hot pressing and sintering is subjected to surface treatment, which includes surface grinding and sandblasting roughening, to obtain a copper-diamond base plate with copper cladding. A positioning groove matching the outer dimensions of the copper-clad copper diamond base plate is processed on the laser printing substrate, and the copper-clad copper diamond base plate is embedded in the positioning groove; the groove depth is 2mm-5mm. The laser selective melting technology is used to directly print fin structures on pure copper cladding. The laser energy is absorbed by the pure copper cladding and avoids penetrating to the copper diamond substrate. When using laser selective melting technology to directly print fin structures on pure copper cladding, the process parameters are as follows: laser power of 300W-700W, scanning speed of 800mm / s-1300mm / s, layer thickness of 20μm-50μm, scanning spacing of 0.06mm-0.10mm, and printing powder of pure copper powder or copper alloy powder with a particle size of 15μm-50μm; the first layer uses remelting scanning to strengthen the interface bonding. After printing, the material is cooled and demolded to obtain copper-diamond copper-coated fins.

2. The method for preparing copper-diamond copper-clad grafted fins according to claim 1, characterized in that, The pretreatment includes grinding, cleaning and drying to make the surface of the copper diamond base plate smooth and clean.

3. The method for preparing copper-diamond copper-clad grafted fins according to claim 1, characterized in that, The pure copper layer is a pure copper foil or a pure copper powder layer, and the pure copper layer uniformly covers the surface of the copper diamond substrate to be bonded.

4. The method for preparing copper-diamond copper-clad grafted fins according to claim 1, characterized in that, The hot pressing sintering process parameters are as follows: sintering temperature is 800℃-1050℃, sintering pressure is 10MPa-40MPa, holding time is 10min-60min, and sintering atmosphere is vacuum or protective atmosphere.

5. The method for preparing copper-diamond copper-clad grafted fins according to claim 1, characterized in that, The surface grinding process ensures that the flatness of the pure copper cladding surface is ≤0.05mm; the sandblasting roughening process uses copper alloy abrasive particles and the sandblasting pressure is 0.3MPa-0.6MPa.

6. The application of a copper-diamond copper-clad grafted fin prepared by the preparation method of the copper-diamond copper-clad grafted fin as described in any one of claims 1-5 in a high heat flux density heat dissipation component.

7. The application according to claim 6, characterized in that, The high heat flux density heat dissipation components include high-power chip heat sinks, third-generation semiconductor device heat sinks, laser equipment heat sinks, data center server liquid cooling heat sinks, or new energy electronic control heat sinks.

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