An irregularly shaped water-cooled backplate and its preparation method

Abstract

This invention discloses a method for preparing an irregularly shaped water-cooled backplate, relating to the field of water-cooled backplate technology, comprising the following steps: annealing an oxygen-free copper blank and then trimming its flatness, followed by precision milling into an oxygen-free copper backplate body and an oxygen-free copper cover plate; machining a stainless steel blank into a stainless steel plug; first, electron beam welding the oxygen-free copper backplate body and the oxygen-free copper cover plate, then electron beam welding the stainless steel plug to the plugging hole of the oxygen-free copper backplate body; coating the weld area between the stainless steel plug and the oxygen-free copper backplate body with a nano-Al₂O₃-TiC composite coating, and then performing in-situ sintering by electron beam to obtain the irregularly shaped water-cooled backplate; performing a water channel sealing test on the irregularly shaped water-cooled backplate to ensure that the sealing performance is qualified; by electron beam welding and setting the Al₂O₃-TiC composite coating, the sealing performance of the weld area, as well as its high temperature resistance, wear resistance, and corrosion resistance, can be improved.

Description

Technical Field

[0001] This invention relates to the field of water-cooled backplate technology, specifically to an irregularly shaped water-cooled backplate and its preparation method. Background Technology

[0002] Water-cooled backplanes are widely used in semiconductor chip manufacturing processes. Magnetron sputtering is a commonly used thin film deposition technique. During high-power sputtering, the target material generates a large amount of heat due to ion bombardment. Water-cooled backplanes can quickly remove this heat, preventing the target material from overheating, deforming, cracking, and desoldering. This ensures the stability and repeatability of the sputtering process, improves the uniformity and quality of thin film deposition, and guarantees the precision and performance of chip manufacturing.

[0003] Currently, the main technology for backplate processing of sputtering targets focuses on backplates with integrated cooling channels. These channels are typically machined onto the backplate, and the process involves forming cooling channels and welding them together. However, welding defects caused by unstable welding processes can significantly lead to serious damage to the sputtering equipment, such as water leakage, during use. Therefore, developing a superior backplate welding process is crucial.

[0004] Patent document CN113667945A discloses a method for preparing an oxygen-free copper backplate with water channels. The method includes: performing a first hot annealing treatment on a billet; shaping a first product and then performing rough milling to obtain a base plate; performing a second hot annealing treatment on the billet; shaping a second product and then performing a first fine milling to obtain a cover plate; assembling the base plate and the cover plate and then welding them; and testing the sealing performance of the water channels after the second fine milling to obtain the oxygen-free copper backplate with water channels. The oxygen-free copper backplate prepared by this method has good cooling and rust prevention effects, and the method can shorten the production cycle and improve production efficiency.

[0005] Patent document CN112045309B discloses a method for preparing a water channel backplate for a target material. The method includes the following steps: machining a T-groove on a copper backplate body, the T-groove comprising a cover plate groove and a water channel arranged from top to bottom; placing a cover plate on the cover plate groove to obtain the copper backplate for the water channel to be welded; fixing the workpiece to be welded on a rigid fixture; setting a laser above the copper backplate for the water channel to be welded; firstly spot welding the copper backplate for the water channel to be welded; performing a first welding operation; and then performing a second welding operation: gradually rotating the welding needle into the joint so that the focal point is located at the joint between the copper backplate body and the cover plate, then simultaneously turning on the stirring friction head and the laser, and simultaneously feeding the stirring friction head and the focal point in the welding direction with the same feed rate, thereby improving the welding efficiency of the target material for the water channel backplate and the service life of the stirring friction head.

[0006] However, in the water-cooled backplates welded using the above-mentioned existing technologies, since the backplate and cover plate are made of the same material, a good welding effect can be obtained. However, in practical applications, the materials of the backplate and the plug are not the same. The plug is often made of stainless steel. Stainless steel and copper have significantly different melting points, coefficients of thermal expansion, and thermal conductivity. Using traditional argon arc welding can easily produce defects such as cracks, reducing the welding strength. Using brazing to weld dissimilar metals such as copper and steel can easily result in weak joints and poor sealing. Summary of the Invention

[0007] The purpose of this invention is to provide an irregularly shaped water-cooled backplate and its preparation method, thereby solving the following technical problems:

[0008] How to improve the welding effect of oxygen-free copper backing plate and stainless steel plug.

[0009] The objective of this invention can be achieved through the following technical solutions:

[0010] In a first aspect, the present invention discloses a method for preparing an irregularly shaped water-cooled backplate, the water-cooled backplate comprising an oxygen-free copper backplate body with water channels, an oxygen-free copper cover plate, and a stainless steel plug; comprising the following steps:

[0011] Step 1: After annealing the oxygen-free copper blank, the flatness is adjusted, and then it is precision milled into the main body of the oxygen-free copper back plate and the oxygen-free copper cover plate. The main body of the oxygen-free copper back plate has a water channel on one side, and the two ends of the water channel have water inlet and water outlet respectively. The center of the water channel has a plug hole for connecting with the stainless steel plug. The stainless steel blank is machined into a stainless steel plug.

[0012] Step 2: First, the oxygen-free copper backplate body and the oxygen-free copper cover plate are electron beam welded together. Then, the stainless steel plug is electron beam welded to the plug hole of the oxygen-free copper backplate body.

[0013] Step 3: Apply a nano-Al2O3-TiC composite coating to the weld area between the stainless steel plug and the oxygen-free copper backplate body, and then perform in-situ sintering by electron beam to obtain the irregular water-cooled backplate.

[0014] Step 4: Conduct a water channel sealing test on the irregularly shaped water-cooled backplate, including helium leakage and water pressure testing, to ensure it passes the test.

[0015] Furthermore, in step one, the annealing conditions are: annealing at 400-500℃ for 2-4 hours;

[0016] Preferably, the annealing conditions are as follows: annealing at 450°C for 3 hours to eliminate processing stress, followed by cooling to 200°C at a cooling rate of 10°C / min and then air cooling.

[0017] Furthermore, in step one, the method for correcting the flatness is to rough mill it until the flatness is ≤1mm.

[0018] Furthermore, in step two, the method for electron beam welding the oxygen-free copper backplate body and the oxygen-free copper cover plate is as follows: first, assemble the oxygen-free copper backplate body and the oxygen-free copper cover plate; then, use a spot punching tool to fix the weld around the seam; then, place the entire assembly into the vacuum chamber of the electron beam welding machine and fix it with a clamp; then, evacuate to 5×10⁻⁶. -3 Pa is used for three-stage welding. The first stage uses a welding current of 20-30mA and a welding speed of 300-600mm / min. This stage is for preheating welding to eliminate internal stress in the material. The second stage uses a welding current of 60-80mA and a welding speed of 300-600mm / min. This stage is used to achieve deep penetration welding. The third stage uses a welding current of 30-40mA and a welding speed of 300-600mm / min. This stage is for surface finishing to reduce weld porosity.

[0019] Preferably, in step two, the method for electron beam welding the oxygen-free copper backplate body and the oxygen-free copper cover plate is as follows: first, assemble the oxygen-free copper backplate body and the oxygen-free copper cover plate; then, use a spot punching tool to fix the weld around the weld seam; then, place the entire assembly into the vacuum chamber of the electron beam welding machine and fix it with a clamp; then, evacuate to 5×10⁻⁶. -3 Pa was used for three-stage welding. The first round of welding used a welding current of 25mA and a welding speed of 450mm / min. The second round used a welding current of 70mA and a welding speed of 450mm / min. The third round used a welding current of 35mA and a welding speed of 450mm / min.

[0020] Furthermore, in step two, the method for electron beam welding the stainless steel plug to the plugging hole of the oxygen-free copper backplate body is as follows: the stainless steel plug is screwed into the plugging hole of the oxygen-free copper backplate body, and then the entire assembly is placed in the vacuum chamber of the electron beam welding machine and fixed with a fixture, and then a vacuum of 5×10 is drawn. -3 Pa, using a 0.3mm thick copper filler for three-stage welding. Copper has a higher thermal conductivity than stainless steel, and the 0.3mm thick copper filler prevents the heat from being conducted away first, thus avoiding the problem of the stainless steel melting first. The welding current for the first pass is 20-30mA, and the welding speed is 300-600mm / min; the welding current for the second pass is 60-80mA, and the welding speed is 300-600mm / min; the welding current for the third pass is 30-40mA, and the welding speed is 500-700mm / min.

[0021] Preferably, in step two, the method for electron beam welding the stainless steel plug to the plugging hole of the oxygen-free copper backplate body is as follows: the stainless steel plug is screwed into the plugging hole of the oxygen-free copper backplate body, and then the entire assembly is placed in the vacuum chamber of the electron beam welding machine and fixed with a fixture, and then a vacuum of 5×10 is drawn. -3 Pa, copper 0.3mm thick, is welded in three stages; the first round of welding current is 25mA and welding speed is 450mm / min; the second round of welding current is 70mA and welding speed is 450mm / min; the third round of welding current is 35mA and welding speed is 600mm / min.

[0022] Further, in step three, the preparation method of the nano-Al2O3-TiC composite coating is as follows: Al2O3 nanoparticles with a particle size of 20-50nm and TiC nanoparticles with a particle size of 30-60nm are mixed at a weight ratio of 3:7 to obtain a mixture. The mixture and 1wt% polyvinylpyrrolidone are added to anhydrous ethanol and stirred evenly to form a suspension with a solid content of 0.5-1.0wt%. The suspension is ultrasonically treated at 300W for 30min to ensure uniform dispersion of particles, thereby obtaining the nano-Al2O3-TiC composite coating.

[0023] Preferably, in step three, the preparation method of the nano-Al2O3-TiC composite coating is as follows: Al2O3 nanoparticles with a particle size of 35nm and TiC nanoparticles with a particle size of 45nm are mixed at a weight ratio of 3:7 to obtain a mixture. The mixture and 1wt% polyvinylpyrrolidone of the mixture mass are added to anhydrous ethanol and stirred evenly to form a suspension with a solid content of 0.8wt%. The suspension is ultrasonically treated at 300W for 30min to ensure uniform dispersion of particles, thereby obtaining the nano-Al2O3-TiC composite coating.

[0024] Furthermore, in step three, the method for coating the weld area between the stainless steel plug and the oxygen-free copper backplate body with a nano-Al2O3-TiC composite coating is as follows: after pretreating the weld area, the nano-Al2O3-TiC composite coating is loaded into a high-pressure airless spray gun and sprayed at a pressure of 0.3-0.5MPa and a distance of 12-20cm, with a final coating thickness of 50-100nm.

[0025] Preferably, in step three, the method for coating the weld area between the stainless steel plug and the oxygen-free copper backplate body with a nano-Al2O3-TiC composite coating is as follows: after pretreating the weld area, the nano-Al2O3-TiC composite coating is loaded into a high-pressure airless spray gun and sprayed at a pressure of 0.4MPa and a distance of 15cm. The spraying is divided into 3-5 thin-layer sprays. After each layer is sprayed, it is left to stand for 5 minutes to dry naturally before the next spray is applied. The final total thickness of the coating is 75nm.

[0026] Furthermore, the method for pre-treating the weld area is as follows: the weld area is ground to remove the oxide layer and flatten the surface, and then the weld area is ultrasonically cleaned by immersing it in acetone or anhydrous ethanol to remove oil and small particles. After drying, it is placed in a vacuum chamber, argon gas is introduced into the vacuum chamber, and then 200-300W plasma treatment is applied for 5 minutes to improve surface activity.

[0027] Preferably, the method for pre-treating the weld area is as follows: the weld area is polished with 600-grit sandpaper, then the weld area is immersed in acetone and ultrasonically cleaned with 300W for 10 minutes, dried and placed in a vacuum chamber, argon gas is introduced into the vacuum chamber, and then 250W plasma treatment is applied for 5 minutes to improve surface activity.

[0028] Furthermore, in step three, the method for in-situ sintering using an electron beam is as follows: the entire assembly is placed inside the vacuum chamber of an electron beam welding machine and fixed with a fixture, then a vacuum of 5 × 10⁻⁶ is drawn. -3 Pa, three-stage sintering is performed in the weld area and the surrounding 2mm range. The first round of welding current is 15mA and welding speed is 800mm / min; the second round of welding current is 20-25mA and welding speed is 500mm / min; the third round of welding current is 10mA and welding speed is 500mm / min.

[0029] Based on this, a preferred method for preparing an irregularly shaped water-cooled backplate is obtained, comprising the following steps:

[0030] Step 1: The oxygen-free copper blank is annealed at 450℃ for 3 hours, then cooled to 200℃ at a cooling rate of 10℃ / min and air-cooled. It is then rough milled to a flatness of ≤1mm and then fine milled into a matching oxygen-free copper back plate body and oxygen-free copper cover plate. The 304 stainless steel blank is machined into a stainless steel plug that matches the oxygen-free copper back plate body.

[0031] Step 2: First, assemble the oxygen-free copper backplate body and the oxygen-free copper cover plate. Then, use a spot punching tool to fix the weld around the seam. Next, place the entire assembly into the vacuum chamber of the electron beam welding machine and fix it with clamps. Then, evacuate to 5×10. -3Pa, three-stage welding is performed: the first round with a welding beam current of 25mA and a welding speed of 450mm / min; the second round with a welding beam current of 70mA and a welding speed of 450mm / min; and the third round with a welding beam current of 35mA and a welding speed of 450mm / min. Then, a stainless steel plug is screwed into the plugging hole of the oxygen-free copper backplate body, and the entire assembly is placed in the vacuum chamber of the electron beam welding machine and fixed with a clamp. A vacuum of 5×10⁻⁶ is then applied. -3 Pa, copper 0.3mm thick, is welded in three stages; the first round of welding current is 25mA and welding speed is 450mm / min; the second round of welding current is 70mA and welding speed is 450mm / min; the third round of welding current is 35mA and welding speed is 600mm / min.

[0032] Step 3: Grind the weld area with 600-grit sandpaper, then immerse the weld area in acetone and ultrasonically clean it at 300W for 10 minutes. After drying, place it in a vacuum chamber, introduce argon gas into the vacuum chamber, and then apply 250W plasma treatment for 5 minutes to improve surface activity. Next, load the nano-Al2O3-TiC composite coating into a high-pressure gasless spray gun and spray it at a pressure of 0.4MPa and a distance of 15cm. Spraying is done in 3-5 thin layers, allowing each layer to dry naturally for 5 minutes before applying the next layer. The final total coating thickness is 75nm. Place the entire assembly into the vacuum chamber of an electron beam welding machine and fix it with clamps, then evacuate to 5×10⁻⁶. -3 Pa, three-stage sintering is carried out in the weld area and the surrounding 2mm range. The first round of welding current is 15mA and welding speed is 800mm / min; the second round of welding current is 23mA and welding speed is 500mm / min; the third round of welding current is 10mA and welding speed is 500mm / min; after natural cooling, an irregular water-cooled backplate is obtained.

[0033] Step 4: Perform helium leakage and water pressure tests on the irregularly shaped water-cooled backplate to ensure that the sealing performance is up to standard.

[0034] Secondly, the present invention also discloses an irregularly shaped water-cooled backplate, which is prepared by the irregularly shaped water-cooled backplate preparation method described above.

[0035] The beneficial effects of this invention are:

[0036] 1. In the preparation process of the irregular water-cooled backplate of the present invention, electron beam welding is used to weld the oxygen-free copper backplate body, the oxygen-free copper cover plate and the stainless steel plug. The electron beam welding process is divided into three stages: the first stage is preheating welding, the second stage is deep melting, and the third stage is surface treatment. This can increase the welding depth and improve the welding quality. At the same time, through high-precision beam current control, welding deformation can be reduced, thereby improving the strength and heat resistance of the weld position.

[0037] 2. In the preparation process of the irregular water-cooled backplate of the present invention, when welding the oxygen-free copper backplate body to the stainless steel plug, a 3mm offset copper is used for welding. This is because the thermal conductivity of copper is greater than that of stainless steel. A 0.3mm offset copper can avoid the problem of the heat of the copper being carried away first, causing the stainless steel to melt first. This makes the transition of the weld area more uniform and beautiful, and the density more uniform, thereby improving its sealing performance and preventing water leakage.

[0038] 3. In the manufacturing process of the irregularly shaped water-cooled backplate of the present invention, an Al2O3-TiC composite coating is applied to the weld area between the oxygen-free copper backplate body and the stainless steel end cap. The melting point of the Al2O3-TiC composite coating is higher than 2000℃, while the melting point of traditional brazing layers is usually lower than 800℃. Therefore, it can significantly improve the high-temperature oxidation resistance of the weld area. At the same time, the coating hardness is 3-5 times higher than that of pure metal welds, thereby reducing wear caused by mechanical friction. Al2O3-TiC is a nano-ceramic material, which can also isolate corrosive media and improve its corrosion resistance. Electron beam in-situ calcination is used. Its high energy density can eliminate residual pores in the coating and improve its density. Moreover, the thermal gradient of in-situ sintering is small, which can reduce microcracks caused by thermal stress and improve product quality. Attached Figure Description

[0039] The invention will now be further described with reference to the accompanying drawings.

[0040] Figure 1 This is a schematic diagram of the structure of the oxygen-free copper backplate body in Embodiment 1 of the present invention;

[0041] Figure 2 This is a schematic diagram of the structure of the oxygen-free copper cover plate in Embodiment 1 of the present invention;

[0042] Figure 3 This is a schematic diagram of the stainless steel plug in Embodiment 1 of the present invention. Detailed Implementation

[0043] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0045] Preparation Example 1

[0046] Preparation of nano-Al₂O₃-TiC composite coating:

[0047] Al₂O₃ nanoparticles with a particle size of 35 nm and TiC nanoparticles with a particle size of 45 nm were mixed at a weight ratio of 3:7 to obtain a mixture. The mixture, along with 1 wt% polyvinylpyrrolidone, was added to anhydrous ethanol and stirred until homogeneous to form a suspension with a solid content of 0.8 wt%. The suspension was ultrasonically treated at 300 W for 30 min to obtain a nano-Al₂O₃-TiC composite coating.

[0048] Example 1

[0049] Fabrication of irregularly shaped water-cooled backplate:

[0050] Step 1: Anneal the oxygen-free copper blank at 450℃ for 3 hours, then cool it to 200℃ at a cooling rate of 10℃ / min and air cool it. Roughly mill it to a flatness of ≤1mm, then finish mill it into the matching oxygen-free copper backplate body as shown in Figure 1 and the figure 2. Figure 2 The oxygen-free copper cover plate shown; the 304 stainless steel blank is machined into a shape that matches the main body of the oxygen-free copper back plate. Figure 3 The stainless steel plug shown.

[0051] Step 2: First, assemble the oxygen-free copper backplate body and the oxygen-free copper cover plate. Then, use a spot punching tool to fix the weld around the seam. Next, place the entire assembly into the vacuum chamber of the electron beam welding machine and fix it with clamps. Then, evacuate to 5×10. -3Pa, three-stage welding is performed: the first round with a welding beam current of 25mA and a welding speed of 450mm / min; the second round with a welding beam current of 70mA and a welding speed of 450mm / min; and the third round with a welding beam current of 35mA and a welding speed of 450mm / min. Then, a stainless steel plug is screwed into the plugging hole of the oxygen-free copper backplate body, and the entire assembly is placed in the vacuum chamber of the electron beam welding machine and fixed with a clamp. A vacuum of 5×10⁻⁶ is then applied. -3 Pa, copper 0.3mm thick, is welded in three stages; the first round of welding current is 25mA and welding speed is 450mm / min; the second round of welding current is 70mA and welding speed is 450mm / min; the third round of welding current is 35mA and welding speed is 600mm / min.

[0052] Step 3: Grind the weld area with 600-grit sandpaper, then immerse the weld area in acetone and ultrasonically clean it at 300W for 10 minutes. After drying, place it in a vacuum chamber, introduce argon gas into the vacuum chamber, and then apply 250W plasma treatment for 5 minutes to improve surface activity. Then, load the nano-Al2O3-TiC composite coating of Preparation Example 1 into a high-pressure gasless spray gun and spray it at a pressure of 0.4MPa and a distance of 15cm. Spraying is done in 3-5 thin layers, and each layer is allowed to stand for 5 minutes to dry naturally before the next layer is sprayed. The final total thickness of the coating is 75nm (monitored in real time by an ellipsometry). Place the whole assembly in the vacuum chamber of an electron beam welding machine and fix it with a clamp, then evacuate to 5×10⁻⁶. -3 Pa, three-stage sintering is carried out in the weld area and the surrounding 2mm range. The first round of welding current is 15mA and welding speed is 800mm / min; the second round of welding current is 23mA and welding speed is 500mm / min; the third round of welding current is 10mA and welding speed is 500mm / min; after natural cooling, an irregular water-cooled backplate is obtained.

[0053] Example 2

[0054] Compared with Example 1, the only difference is that in step two: when performing three-stage welding, the welding current for the first round is 20mA, the welding current for the second round is 60mA, and the welding current for the third round is 30mA; when performing three-stage welding on a copper 0.3mm thick sheet, the welding current for the first round is 20mA, the welding current for the second round is 60mA, and the welding current for the third round is 30mA; other steps and conditions remain the same, and the irregularly shaped water-cooled backplate is finally obtained.

[0055] Example 3

[0056] Compared with Example 1, the only difference is that in step two: when performing three-stage welding, the welding current for the first round is 30mA, the welding current for the second round is 80mA, and the welding current for the third round is 40mA; when performing three-stage welding on a copper 0.3mm thick sheet, the welding current for the first round is 30mA, the welding current for the second round is 80mA, and the welding current for the third round is 40mA; other steps and conditions remain the same, and finally, an irregularly shaped water-cooled backplate is obtained.

[0057] Example 4

[0058] Compared with Example 1, the only difference is that in step three: the welding current for the second round is 20mA; the other steps and conditions remain the same, and the irregular water-cooled backplate is finally obtained.

[0059] Example 5

[0060] Compared with Example 1, the only difference is that in step three: the welding current for the second round is 25mA; the other steps and conditions remain the same, and the irregular water-cooled backplate is finally obtained.

[0061] Comparison Machine 1

[0062] Compared with Example 1, the only difference is that step three is omitted, and the product obtained in step two is directly cooled naturally to be used as the final irregular water-cooled back plate. Other steps and conditions remain the same.

[0063] Comparative Example 2

[0064] Compared with Example 1, the only difference is that in step two, the three-segment welding of the 0.3mm copper was changed to a three-segment welding of the center section; the other steps and conditions remain the same, and the irregular water-cooled backplate is finally obtained.

[0065] Comparative Example 3

[0066] Compared with Example 1, the only difference is that in step two, the three-segment welding of the copper 0.3mm was changed to a one-segment welding, and the welding beam current was 80mA; the other steps and conditions remained the same, and the irregular water-cooled backplate was finally obtained.

[0067] Comparative Example 4

[0068] Compared with Example 1, the only difference is that in step two: when performing three-segment welding, the three-segment welding with 0.3mm copper is changed to argon arc welding; other steps and conditions remain the same, and finally, the irregular water-cooled backplate is obtained.

[0069] Comparative Example 5

[0070] Compared with Example 1, the only difference is that in step two, the three-segment welding of the copper 0.3mm is replaced by argon arc welding; at the same time, step three is cancelled, and the product obtained in step two is directly cooled naturally to be used as the final irregular water-cooled back plate, while other steps and conditions remain the same.

[0071] The irregularly shaped water-cooled backplates prepared in Examples 1-5 and Comparative Examples 1-5 were subjected to sealing tests, including helium gas testing and water pressure testing. The weld area was also observed. The testing methods are as follows:

[0072] Helium detection: Connect the irregularly shaped water-cooled backplate to the helium mass spectrometer and evacuate it. Then, purge helium around the irregularly shaped water-cooled backplate at a pressure of 0.8 MPa. Detect the helium inside the irregularly shaped water-cooled backplate using the helium mass spectrometer and record the time from the start to the detection of helium. The total detection time is 1 hour.

[0073] Water pressure test: Water at a pressure of 0.6 MPa is introduced into the irregular water-cooling backplate. The water pressure is increased by 0.1 MPa every 5 minutes. Observe whether the irregular water-cooling backplate leaks water and record the highest water pressure that the irregular water-cooling backplate can withstand.

[0074] Weld zone: Observation method.

[0075] The test results are listed in Table 1, as follows:

[0076] Table 1

[0077] Example 1 No detection within 1 hour 1.9 The transition is smooth and aesthetically pleasing. Example 2 No detection within 1 hour 1.8 The transition is smooth and aesthetically pleasing. Example 3 No detection within 1 hour 1.8 The transition is smooth and aesthetically pleasing. Example 4 No detection within 1 hour 1.8 The transition is smooth and aesthetically pleasing. Example 5 No detection within 1 hour 1.8 The transition is smooth and aesthetically pleasing. Comparative Example 1 48 1.2 The transition is smooth and aesthetically pleasing. Comparative Example 2 No detection within 1 hour 1.7 Uneven transition Comparative Example 3 55 1.5 The transition is relatively even Comparative Example 4 40 0.9 Uneven transition Comparative Example 5 35 0.8 Uneven transition

[0078] Analysis of the data in Table 1 shows that, compared with Comparative Examples 1-5, the irregular water-cooled backplates prepared in Examples 1-5 have significantly better helium gas detection and water pressure detection effects, and the transition of the weld area is more uniform and aesthetically pleasing.

[0079] The high-temperature resistance, wear resistance, and corrosion resistance of the weld area of ​​the irregularly shaped water-cooled backplates prepared in Examples 1-5 and Comparative Examples 1-5 were tested. The testing methods were as follows:

[0080] High temperature resistance: The welded sample was placed in a high temperature furnace and kept at a constant temperature of 1000℃ for 100 hours in an air environment. After natural cooling, the mass change before and after oxidation was measured by a precision balance, and the oxidation weight gain rate was calculated.

[0081] Wear resistance: The weld area was tested using a friction and wear tester. The wear material was SiC ball (6mm in diameter), the load was 10N, the sliding speed was 0.1m / s, and the total sliding distance was 1000m. The wear volume was calculated.

[0082] Corrosion resistance: Perform salt spray test (neutral salt spray, ASTM B 117) and calculate the corrosion area.

[0083] The test results are listed in Table 2, as follows:

[0084] Table 2

[0085] Example 1 0.08 <![CDATA[≤5×10 -6 ]]> 0.85 Example 2 0.09 <![CDATA[≤5×10 -6 ]]> 0.91 Example 3 0.09 <![CDATA[≤5×10 -6 ]]> 0.92 Example 4 0.09 <![CDATA[≤5×10 -6 ]]> 0.89 Example 5 0.09 <![CDATA[≤5×10 -6 ]]> 0.88 Comparative Example 1 2.65 <![CDATA[≥2×10 -4 ]]> 41.2 Comparative Example 2 1.01 <![CDATA[≤5×10 -6 ]]> 0.95 Comparative Example 3 1.00 <![CDATA[≤5×10 -6 ]]> 0.96 Comparative Example 4 1.25 <![CDATA[≤5×10 -6 ]]> 0.99 Comparative Example 5 2.72 <![CDATA[≥2×10 -4 ]]> 49.6

[0086] Analysis of the data in Table 2 shows that, except for Comparative Examples 1 and 5, the oxidation weight gain rate, wear volume, and corrosion area of ​​the weld seam of the other irregular water-cooled backplates are significantly lower. This indicates that the nano Al2O3-TiC composite coating can improve the high temperature resistance, wear resistance, and corrosion resistance of the weld seam.

[0087] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A method for preparing an irregularly shaped water-cooled backplate, the water-cooled backplate comprising an oxygen-free copper backplate body with water channels, an oxygen-free copper cover plate, and a stainless steel plug; characterized in that, Includes the following steps: Step 1: After annealing the oxygen-free copper blank, adjust its flatness and then precision mill it into the main body of the oxygen-free copper back plate and the oxygen-free copper cover plate; process the stainless steel blank into stainless steel plugs using a machine tool. Step 2: First, the oxygen-free copper backplate body and the oxygen-free copper cover plate are electron beam welded together. Then, the stainless steel plug is electron beam welded to the plug hole of the oxygen-free copper backplate body. Step 3: Apply a nano-Al2O3-TiC composite coating to the weld area between the stainless steel plug and the oxygen-free copper backplate body, and then perform in-situ sintering by electron beam to obtain the irregular water-cooled backplate. Step 4: Conduct a water channel sealing test on the irregularly shaped water-cooled backplate to ensure that the sealing is up to standard; In step three, the preparation method of the nano-Al2O3-TiC composite coating is as follows: Al2O3 nanoparticles with a particle size of 20-50nm and TiC nanoparticles with a particle size of 30-60nm are mixed at a weight ratio of 3:7 to obtain a mixture. The mixture and 1wt% polyvinylpyrrolidone are added to anhydrous ethanol and stirred evenly to form a suspension with a solid content of 0.5-1.0wt%. The suspension is ultrasonically treated at 300W for 30min to obtain the nano-Al2O3-TiC composite coating. In step three, the method for in-situ sintering using an electron beam is as follows: the entire assembly is placed inside the vacuum chamber of an electron beam welding machine and fixed with clamps, then a vacuum of 5×10⁻⁶ is drawn. -3 Pa, three-stage sintering is carried out in the weld area and the surrounding 2mm range. The first round of welding current is 15mA and welding speed is 800mm / min; the second round of welding current is 20-25mA and welding speed is 500mm / min; the third round of welding current is 10mA and welding speed is 500mm / min.

2. The method for preparing the irregularly shaped water-cooled backplate according to claim 1, characterized in that, In step one, the annealing conditions are as follows: annealing at 400-500℃ for 2-4 hours, followed by cooling to 200℃ at a cooling rate of 10℃ / min and then air cooling.

3. The method for preparing the irregularly shaped water-cooled backplate according to claim 1, characterized in that, In step one, the method for correcting the flatness is to rough mill it until the flatness is ≤1mm.

4. The method for preparing the irregularly shaped water-cooled backplate according to claim 1, characterized in that, In step two, the method for electron beam welding the oxygen-free copper backplate body and the oxygen-free copper cover plate is as follows: First, assemble the oxygen-free copper backplate body and the oxygen-free copper cover plate, then use a spot punching tool to fix the weld around the seam, then place the whole assembly into the vacuum chamber of the electron beam welding machine and fix it with a clamp, and then evacuate to 5×10 -3 Pa is used for three-stage welding. The welding current in the first round is 20-30mA and the welding speed is 300-600mm / min; the welding current in the second round is 60-80mA and the welding speed is 300-600mm / min; and the welding current in the third round is 30-40mA and the welding speed is 300-600mm / min.

5. The method for preparing the irregularly shaped water-cooled backplate according to claim 1, characterized in that, In step two, the method for electron beam welding the stainless steel plug to the plugging hole of the oxygen-free copper backplate body is as follows: the stainless steel plug is screwed into the plugging hole of the oxygen-free copper backplate body, and then the entire assembly is placed in the vacuum chamber of the electron beam welding machine and fixed with a fixture. Then, a vacuum of 5×10⁻⁶ is drawn. -3 Pa, copper 0.3mm thick, is welded in three stages. The first round of welding uses a welding current of 20-30mA and a welding speed of 300-600mm / min; the second round uses a welding current of 60-80mA and a welding speed of 300-600mm / min; and the third round uses a welding current of 30-40mA and a welding speed of 500-700mm / min.

6. The method for preparing the irregularly shaped water-cooled backplate according to claim 1, characterized in that, In step three, the method for applying a nano-Al2O3-TiC composite coating to the weld area between the stainless steel plug and the oxygen-free copper backplate body is as follows: after pretreating the weld area, the nano-Al2O3-TiC composite coating is loaded into a high-pressure airless spray gun and sprayed at a pressure of 0.3-0.5MPa and a distance of 12-20cm, with a final coating thickness of 50-100nm.

7. The method for preparing the irregularly shaped water-cooled backplate according to claim 6, characterized in that, The method for pre-treating the weld area is as follows: grind the weld area, then immerse the weld area in acetone or anhydrous ethanol for ultrasonic cleaning, dry it, place it in a vacuum chamber, introduce argon gas into the vacuum chamber, and then apply 200-300W plasma treatment for 5 minutes.

8. An irregularly shaped water-cooled backplate, characterized in that, The irregularly shaped water-cooled backplate is prepared by the method described in any one of claims 1-7.

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