Vacuum brazing process for a target cooling system

Abstract

The application discloses a vacuum brazing process of a target material cooling system, and comprises the following steps: S1, assembling: after the non-water channel part of the copper-chromium bottom plate is smeared with nickel-based soldering paste, the copper-chromium bottom plate is assembled into a copper-chromium square cavity, then nickel-based soldering paste is applied to the surrounding of the internal joint of the copper-chromium square cavity, the surrounding of the joint of the stainless steel water nozzle, the copper-chromium square cavity and the copper-chromium bottom plate; and after the assembling is completed, the copper-chromium bottom plate and the stainless steel water nozzle are provided with certain pressure; S2, vacuum brazing: the assembled component of step S1 is placed into a vacuum furnace, and the vacuum brazing is completed by adopting a gradient heating mode; and oil immersion treatment is carried out after the vacuum brazing; S3, water pressure detection: water pressure detection is carried out by using a water pressure detection device; the vacuum brazing process is one-time assembling of copper-chromium parts and stainless steel parts, and the vacuum brazing is carried out in a vacuum furnace, so that the one-time welding and the deformation problem of post-welding leak detection are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of welding technology, in particular to a vacuum brazing process of a target cooling system. BACKGROUND

[0002] The target cooling system, namely the target cooling back plate, is formed by welding the cover plate and the base with the cooling water channel. In the process of magnetron sputtering coating, the target must withstand the cooling water pressure on the back and the vacuum negative pressure on the front, so the target back plate is particularly important. Generally, aluminum alloy, copper and copper alloy back plates are selected as the target back plate, mainly because the materials have high strength and good thermal conductivity, which can meet the needs of the semiconductor industry.

[0003] Vacuum brazing refers to the heating of workpieces in a vacuum chamber, mainly used for the welding of high-quality products and easily oxidized materials. The vacuum brazing furnace includes a pressure vessel with a cylindrical sidewall and a door, the size and position of the door are designed to close one end of the cylindrical sidewall. A workpiece handling system is installed on the door of the pressure vessel to support the metal workpiece for heat treatment or brazing. The workpiece handling system includes a device that rotates the workpiece during the treatment process. A vacuum system can be connected to the workpiece to make the internal pressure of the workpiece lower than atmospheric pressure during brazing.

[0004] The existing welding method of the target cooling system is mainly diffusion welding, but diffusion welding is prone to deformation of parts, and materials such as oxygen-free copper are often used for welding, but materials such as oxygen-free copper are prone to deformation under high pressure. Therefore, the process of the present application adopts vacuum brazing technology to weld the target cooling system of copper-chromium materials. SUMMARY

[0005] To solve the above technical problems, the present application provides a vacuum brazing process of a target cooling system.

[0006] The technical scheme of the present application is: a vacuum brazing process of a target cooling system, comprising the following steps:

[0007] S1, assembling the target cooling system:

[0008] After the copper-chromium back plate, stainless steel nozzle and copper-chromium square cavity are cleaned to be free of oil, oxidation and pollutants, the copper-chromium back plate, stainless steel nozzle and copper-chromium square cavity are activated at each welding position. The activation treatment is: etching each welding position with etching liquid, the etching thickness is 1 / 35~1 / 40 of the welding position thickness, the etching time is 9~11min, then applying an activating agent on the etched position, and drying in an inert gas with a temperature of 150~180℃ after the application is completed.

[0009] Applying nickel-based solder paste to the non-water channel portion of the copper-chromium base plate, then assembling the copper-chromium base plate coated with nickel-based solder paste into the copper-chromium square cavity, applying nickel-based solder paste around the inner joint of the copper-chromium square cavity, and applying nickel-based solder paste around the portion where the stainless steel water nozzle, the copper-chromium square cavity, and the copper-chromium base plate are connected to each other;

[0010] The amount of the activator applied is 2-5% of the mass of the nickel-based solder paste;

[0011] Then, with an extrusion pressure of 2~5MPa and a 2 Extrude the nickel-based solder paste onto the area where it is applied. Repeat the extrusion 3 to 5 times after extruding all the areas to evenly disperse the nickel-based solder paste layer.

[0012] After the assembly is completed, the copper-chromium base plate and the stainless steel water nozzle are equipped with weights to obtain the assembled target cooling system;

[0013] S2. Vacuum brazing:

[0014] The target cooling system assembled in step S1 is placed in a vacuum chamber with a degree of 5×10 -2 In the vacuum furnace of pa, the vacuum furnace control program is started and the vacuum brazing is completed by using the gradient heating method;

[0015] After vacuum brazing, immerse the target cooling system in 90-100°C engine oil for 1.5-2 hours, and pass a current of 50 Hz and 50-70 mA / mm during the immersion process. After immersion, dry the target under 25-30 W UV power for 5-10 minutes.

[0016] S3. Water pressure detection:

[0017] The target material cooling system obtained in step S2 is subjected to a water pressure test using a water pressure test device, and the pressure leakage rate per minute is less than 0.1%, and the deformation is ≤5%.

[0018] Furthermore, in step S2, the gradient heating method is: first, the temperature is raised to 345~355℃ within 35~40min, and kept warm for 20~30min; then, the temperature is raised to 645~655℃ within 40~60min, and kept warm for 30~40min; then, the temperature is raised to 965~975℃ within 40~60min, and kept warm for 30~40min; finally, the temperature is raised to 1045~1055℃ within 20~30min, and kept warm for 5~8min; after the insulation is completed, the power is turned off and the temperature is cooled. When the temperature drops to 595~605℃, nitrogen or argon is filled in, and the furnace is taken out of the furnace after the temperature drops to 45~55℃.

[0019] Note: The temperature rising time and the holding time of each gradient in the above gradient heating are not much different, and the temperature of each gradient is 300 DEG C, which can make the heating effect more uniform.

[0020] Further, the nickel-based welding paste is BNi2 welding paste, and the thickness of the nickel-based welding paste applied to each part is 2-3 mm.

[0021] Note: The BNi-2 welding paste has a lower melting temperature and good wettability during brazing, and the brazed joint formed has good high-temperature strength, excellent oxidation resistance and corrosion resistance; too thick welding paste can easily cause the welding paste to collapse, and too thin welding paste can cause insufficient welding paste or virtual welding problems.

[0022] Further, the weight is: placing a weight block on the contact surface of the copper-chromium bottom plate and the contact surface of the stainless steel nozzle at a ratio of 95-105 g / cm 2 .

[0023] Note: The weight can make the center of gravity of the copper-chromium bottom plate and the stainless steel nozzle more stable, and too much weight can damage the assembly of the copper-chromium bottom plate and the stainless steel nozzle, and too little weight can not achieve the stability effect.

[0024] Further, in step S3, the water pressure detection method is: holding pressure for 25-35 min under 0.55-0.65 MPa water pressure.

[0025] Note: The above water pressure detection method is simple, and the leak detection effect can be known at a glance, and the strength test can also be achieved.

[0026] Further, in step S1, the cleaning method is: ultrasonic cleaning in a 99% pure acetone solution for 25-40 s, the ultrasonic frequency is 30-40 KHz, and the ultrasonic power is 500-1500 W.

[0027] Note: Acetone has good cleaning performance and is safe for metals without corrosion, which can meet the cleaning needs of parts in many fields; and ultrasonic assisted cleaning can greatly improve the cleanliness of the surface of the cleaned parts, and the cleaning speed is fast.

[0028] Further, in step S1, before applying the nickel-based welding paste, each part where the nickel-based welding paste is applied is sandblasted to a roughness of 1.5-2.5 μm.

[0029] Note: Sandblasting can greatly improve the bonding force of the workpiece and the filler metal, making the nickel-based welding paste more firm and better quality after welding.

[0030] Further, in step S1, the etching solution is composed of 5-15wt% hydrofluoric acid, 35-55wt% nitric acid, 5-15wt% fluorosilicic acid and the balance of water.

[0031] Description: The acidic etching solution has the advantages of uniform etching, fast speed, low cost, reproducibility and the like.

[0032] Further, in step S1, the activator is composed of sodium dodecyl sulfate, polydimethylsiloxane and diphenylsilanediol in a mass ratio of 9:1:0.5-0.7.

[0033] Description: The addition of appropriate polydimethylsiloxane and a small amount of diphenylsilanediol in the commonly used activator components can improve the activation performance of the activator.

[0034] The present application has the following advantages:

[0035] (1) The vacuum brazing process selects nickel-based welding paste as the material for vacuum brazing, assembles copper-chromium parts and stainless steel parts of different materials at one time, and completes the welding of metals of different materials in a vacuum furnace at one time using corresponding tooling; solves the problems of one-time welding and deformation after welding; the vacuum brazing process has fewer steps and a short process, can weld at one time at high temperature, has good welding strength and high reliability.

[0036] (2) The vacuum brazing process etches each welding position with an etching solution, the etched product has no burrs, and the efficiency and precision are high; an etching thickness that is too thick or too thin will affect the application effect of the activator at the welding position, and applying a certain amount of activator at the etching position can enhance the activity of the welding paste, so that the components of the subsequent welding paste can volatilize and melt faster at high temperature, thereby improving the efficiency of vacuum brazing; drying in inert gas can make the activator firmly adhere to the etching position, preventing affecting other positions.

[0037] (3) The vacuum brazing process uniformly disperses the welding paste after applying the welding paste through extrusion, so that the welding paste can be more closely attached to the inside of the welding position under pressure, and the welding paste and the welding position body are more firmly combined; and the thickness distribution is more uniform under pressure, thereby improving the vacuum brazing effect, reducing the deformation amount and pressure penetration rate generated during long-term use, and improving the service life of the target cooling system.

[0038] (4) The vacuum brazing process of the application carries out oil immersion treatment on the target material cooling system after vacuum brazing, and the hot oil is soaked into the target material cooling system for a period of time, so that the corrosion resistance and wear resistance of the target material cooling system are improved, thereby prolonging the service life of the target material cooling system; and during the oil immersion process, an electric current is passed to make the target material cooling system surface adhere to an oil film, further improving the corrosion resistance and wear resistance of the target material cooling system and accelerating the penetration rate of the hot oil; after the oil immersion is completed, the oil film is stably adhered to the surface of the target material cooling system through ultraviolet drying, so that the target material cooling system is protected while preventing uneven drying and oil film rupture. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 is a schematic diagram of a target material cooling system assembly;

[0040] Figure 2 is a schematic diagram of a target material cooling system water channel cross-sectional structure;

[0041] Among them, 1-copper-chromium bottom plate, 2-stainless steel nozzle, 3-copper-chromium square cavity. DETAILED DESCRIPTION

[0042] The application will be further described in detail below in conjunction with specific embodiments to better embody the advantages of the application. EMBODIMENT

[0043] A vacuum brazing process of a target material cooling system, comprising the following steps:

[0044] S1, assemble the target material cooling system:

[0045] After the copper-chromium bottom plate 1, the stainless steel nozzle 2, and the copper-chromium square cavity 3 are cleaned to be free of oil, oxidation, and contaminants on the surface, the cleaning method is ultrasonic cleaning in a 99% pure acetone solution for 30s, with an ultrasonic frequency of 35KHz and an ultrasonic power of 1000W;

[0046] Each welding position of the copper-chromium bottom plate 1, the stainless steel nozzle 2, and the copper-chromium square cavity 3 is subjected to activation treatment, which is etching each welding position with an etching solution to a thickness of 1 / 38 of the welding position, and etching for 10min, and then applying an activator to the etched position and drying in a helium gas at a temperature of 165℃;

[0047] The etching solution is composed of 10wt% hydrofluoric acid, 40wt% nitric acid, 10wt% fluorosilicic acid, and the balance of water; the activator is composed of sodium dodecyl sulfate, polydimethylsiloxane, and diphenylsilanediol in a mass ratio of 9:1:0.6;

[0048] The BNi2 solder paste is applied to the non-waterway part of the copper-chromium bottom plate 1, the copper-chromium bottom plate 1 coated with the BNi2 solder paste is assembled into the copper-chromium square cavity 3, the BNi2 solder paste is applied to the periphery of the internal joint of the copper-chromium square cavity 3, and the BNi2 solder paste is applied to the periphery of the part connecting the stainless steel nozzle 2, the copper-chromium square cavity 3 and the copper-chromium bottom plate 1;

[0049] The application amount of the activator is 3.5% of the mass of the nickel-based solder paste;

[0050] The nickel-based solder paste coated part is extruded at an extrusion pressure of 4 MPa and a single extrusion area of 0.8 cm 2 , and after all the areas are extruded, the nickel-based solder paste layer is uniformly dispersed by repeating the extrusion for 4 times, so that the thickness of the BNi2 solder paste applied to each part is 2.5 mm;

[0051] After the assembly is completed, a weight is placed on the contact surface of the copper-chromium bottom plate 1 and the contact surface of the stainless steel nozzle 3 at a ratio of 100 g / cm 2 , so as to obtain the assembled target cooling system;

[0052] S2, vacuum brazing:

[0053] The target cooling system assembled in step S1 is placed into a vacuum furnace with a vacuum degree of 5*10 -2 pa, a vacuum furnace control program is started, and the vacuum brazing is completed by using a gradient heating mode;

[0054] The gradient heating mode is that the temperature is first increased to 350℃ within 38 min, and then kept for 25 min; then the temperature is increased to 650℃ within 50 min, and then kept for 35 min; then the temperature is increased to 970℃ within 50 min, and then kept for 35 min; finally, the temperature is increased to 1050℃ within 25 min, and then kept for 7 min; after the keeping, the power is turned off to cool the target cooling system with the furnace, nitrogen is filled in when the temperature drops to 600℃ to make the pressure value reach 60 KPa, and the furnace is taken out when the temperature drops to 50℃;

[0055] After the furnace is taken out, the target cooling system is immersed in machine oil at 95℃ for 1.8 h, and a current with a frequency of 50 Hz and a density of 60 mA / mm is passed through during the oil immersion; after the oil immersion, the target cooling system is dried under a UV power of 28 W for 8 min;

[0056] S3, water pressure detection:

[0057] The target cooling system obtained in step S2 is subjected to water pressure detection by using a commercially available water pressure detection device, the pressure is kept for 30 min under a water pressure of 0.6 MPa, the pressure leakage rate per minute is 0.07%, and the deformation amount is 3.5%. Embodiment

[0058] The difference between this embodiment and embodiment 1 is that in step S1, the nickel-based solder paste is extruded on the contact surface of the copper-chromium base plate 1 and the contact surface of the stainless steel nozzle 2 at an extrusion pressure of 2 MPa and a single extrusion area of 0.5 cm 2 After extruding on all areas, the extrusion is repeated 3 times. The thickness of the BNi2solder paste applied on each area is 2 mm. Embodiment

[0059] The difference between this embodiment and embodiment 1 is that in step S1, the nickel-based solder paste is extruded on the contact surface of the copper-chromium base plate 1 and the contact surface of the stainless steel nozzle 2 at an extrusion pressure of 5 MPa and a single extrusion area of 1 cm 2 After extruding on all areas, the extrusion is repeated 5 times. The thickness of the BNi2solder paste applied on each area is 3 mm. Embodiment

[0060] The difference between this embodiment and embodiment 1 is that in step S1, the contact surface of the copper-chromium base plate 1 and the contact surface of the stainless steel nozzle 2 are placed with a weight of 95 g / cm 2 . Embodiment

[0061] The difference between this embodiment and embodiment 1 is that in step S1, the contact surface of the copper-chromium base plate 1 and the contact surface of the stainless steel nozzle 2 are placed with a weight of 105 g / cm 2 . Embodiment

[0062] The difference between this embodiment and embodiment 1 is that in step S1, the cleaning method is ultrasonic cleaning in a 99% pure acetone solution for 25 s, with an ultrasonic frequency of 30 KHz and an ultrasonic power of 500 W. Embodiment

[0063] The difference between this embodiment and embodiment 1 is that in step S1, the cleaning method is ultrasonic cleaning in a 99% pure acetone solution for 40 s, with an ultrasonic frequency of 40 KHz and an ultrasonic power of 1500 W. Embodiment

[0064] The difference between this embodiment and embodiment 1 is that in step S1, before applying the nickel-based solder paste, each area where the nickel-based solder paste is to be applied is sandblasted to a roughness of 2.0 μm. Embodiment

[0065] The difference between this embodiment and embodiment 8 is that in step S1, before applying the nickel-based solder paste, each area where the nickel-based solder paste is to be applied is sandblasted to a roughness of 1.5 μm. Embodiment

[0066] The difference between this embodiment and embodiment 8 is that, in step S1, before the nickel-based solder paste is applied, sand blasting is performed on each part to which the nickel-based solder paste is to be applied until the roughness of each part is 2.5 μm. Embodiment

[0067] The difference between this embodiment and embodiment 1 is that, in step S2, the gradient heating mode is: first, the temperature is raised to 345°C within 35 min, and then kept for 20 min; then the temperature is raised to 645°C within 40 min, and then kept for 30 min; then the temperature is raised to 965°C within 40 min, and then kept for 30 min; finally, the temperature is raised to 1045°C within 20 min, and then kept for 5 min; after the keeping step is completed, the power is turned off to allow the target cooling system to cool down with the furnace, and when the temperature drops to 595°C, nitrogen is filled to make the pressure value reach 60 KPa, and when the temperature drops to 45°C, the furnace is discharged. Embodiment

[0068] The difference between this embodiment and embodiment 1 is that, in step S2, the gradient heating mode is: first, the temperature is raised to 355°C within 40 min, and then kept for 30 min; then the temperature is raised to 655°C within 60 min, and then kept for 40 min; then the temperature is raised to 975°C within 60 min, and then kept for 40 min; finally, the temperature is raised to 1055°C within 30 min, and then kept for 8 min; after the keeping step is completed, the power is turned off to allow the target cooling system to cool down with the furnace, and when the temperature drops to 605°C, nitrogen or argon is filled to make the pressure value reach 60 KPa, and when the temperature drops to 55°C, the furnace is discharged. Embodiment

[0069] The difference between this embodiment and embodiment 1 is that, in step S2, the target cooling system is immersed in machine oil at 90°C for 1.5 h. Embodiment

[0070] The difference between this embodiment and embodiment 1 is that, in step S2, the target cooling system is immersed in machine oil at 100°C for 2 h. Embodiment

[0071] The difference between this embodiment and embodiment 1 is that, in step S2, the current density is 50 mA / mm. Embodiment

[0072] The difference between this embodiment and embodiment 1 is that, in step S2, the current density is 70 mA / mm. Embodiment

[0073] The difference between this embodiment and embodiment 1 is that, in step S2, the power of the ultraviolet drying is 25 W, and the time is 5 min. Embodiment

[0074] The difference between this embodiment and embodiment 1 is that in step S2, the power of the ultraviolet drying is 30 W, and the time is 10 min. Embodiment

[0075] The difference between this embodiment and embodiment 1 is that in step S3, the water pressure detection method is to maintain the pressure for 25 min under 0.65 MPa water pressure. Embodiment

[0076] The difference between this embodiment and embodiment 1 is that in step S3, the water pressure detection method is to maintain the pressure for 35 min under 0.55 MPa water pressure. Embodiment

[0077] The difference between this embodiment and embodiment 1 is that the etching thickness is 1 / 40 of the thickness of the welding site, and the etching time is 9 min. Embodiment

[0078] The difference between this embodiment and embodiment 1 is that the etching thickness is 1 / 35 of the thickness of the welding site, and the etching time is 11 min. Embodiment

[0079] The difference between this embodiment and embodiment 1 is that the etching site is smeared with an activator accounting for 2% of the mass of the nickel-based welding paste. Embodiment

[0080] The difference between this embodiment and embodiment 1 is that the etching site is smeared with an activator accounting for 5% of the mass of the nickel-based welding paste. Embodiment

[0081] The difference between this embodiment and embodiment 1 is that the activator is composed of sodium dodecyl sulfate, polydimethylsiloxane, and diphenylsilanediol in a mass ratio of 9:1:0.5. Embodiment

[0082] The difference between this embodiment and embodiment 1 is that the activator is composed of sodium dodecyl sulfate, polydimethylsiloxane, and diphenylsilanediol in a mass ratio of 9:1:0.7. Embodiment

[0083] The difference between this embodiment and embodiment 1 is that after the smearing is completed, it is placed in helium gas with a temperature of 150°C for drying. Embodiment

[0084] The difference between this embodiment and embodiment 1 is that after the smearing is completed, it is placed in helium gas with a temperature of 180°C for drying. Embodiment

[0085] The difference between the present embodiment and embodiment 1 is that the etching solution is composed of 5wt% hydrofluoric acid, 55wt% nitric acid, 5wt% fluorosilicic acid and the balance of water. Embodiment

[0086] The difference between the present embodiment and embodiment 1 is that the etching solution is composed of 15wt% hydrofluoric acid, 35wt% nitric acid, 15wt% fluorosilicic acid and the balance of water.

[0087] For each target material cooling system welded in each embodiment, 5 samples of each embodiment are taken to test the performance of the target material cooling system, and the average of the performance measurement results of the 5 samples of each embodiment is taken as the performance measurement result of the embodiment. The specific exploration is as follows:

[0088] 1. Explore the influence of parameters in the whole process on the deformation amount of the target material cooling system.

[0089] Examples 1-18, 21-31 and control examples 1-3 are used for experimental comparison, and the results are shown in Table 1:

[0090] Table 1 Influence of examples and control examples on the deformation amount of the target material cooling system

[0091]

[0092] The difference between control example 1 and embodiment 1 is that the activator is composed of sodium dodecyl sulfate and polydimethylsiloxane in a mass ratio of 9.6:1;

[0093] The difference between control example 2 and embodiment 1 is that it is dried in air at 165℃;

[0094] The difference between control example 3 and embodiment 1 is that the activator is not etched but directly applied;

[0095] From the results in Table 1, it can be seen that when the activator lacks diphenylsilanediol, lacks an inert gas environment, and lacks etching, the welding effect will be weakened compared to embodiment 15;

[0096] From the examples 1-18 and 21-30, it can be seen that when the parameters of the etching treatment are too large or too small, the thickness of the BNi2 solder paste is too thick or too thin, the weight of the weight block is too heavy or too light, the current of the oil immersion treatment is too large or too small, and the power of the ultraviolet drying is too large or too small, the effect of vacuum brazing will be reduced. The effects of examples 13 and 14 on the brazing effect can be ignored in the water pressure test, so they are not discussed. The deformation of examples 7, 12 and 14 is relatively small compared with examples 1-6. However, example 7 requires more time and more ultrasonic power, but the effect of reducing the deformation is not outstanding. Examples 12 and 14 require higher temperature and longer time, but the effect is improved slightly, so the effect of example 1 is better. Compared with examples 8-10, the sand blasting treatment reduces the deformation degree.

Claims

1. A vacuum brazing process for a target cooling system, characterized by, The method comprises the following steps: S1, assembling a target cooling system: After the copper-chromium base plate (1), the stainless steel nozzle (2), and the copper-chromium square cavity (3) are cleaned to be free of oil, oxidation, and pollutants, the copper-chromium base plate (1), the stainless steel nozzle (2), and the copper-chromium square cavity (3) are activated at the welding positions, the activation treatment is etching the welding positions with an etching solution, the etching thickness is 1 / 35~1 / 40 of the welding position thickness, the etching time is 9~11min, and then the activated agent is applied to the etching positions, and the copper-chromium base plate (1), the stainless steel nozzle (2), and the copper-chromium square cavity (3) are dried in an inert gas at a temperature of 150~180℃; The nickel-based solder paste is applied to the non-waterway position of the copper-chromium base plate (1), the copper-chromium base plate (1) coated with the nickel-based solder paste is assembled into the copper-chromium square cavity (3), the nickel-based solder paste is applied to the four sides of the internal junction of the copper-chromium square cavity (3), and the nickel-based solder paste is applied to the positions around the connection between the stainless steel nozzle (2), the copper-chromium square cavity (3), and the copper-chromium base plate (1). The application amount of the activated agent is 2~5% of the mass of the nickel-based solder paste. Then, the area of 0.5-1 cm 2 squeezed by 2-5 MPa is coated with nickel-based solder paste, and after all the areas are squeezed, the nickel-based solder paste layer is evenly dispersed by repeating the squeezing for 3-5 times. The copper-chromium base plate (1) and the stainless steel nozzle (2) are provided with a weight after assembly, and a target cooling system is obtained. S2, vacuum brazing: The step S1 assembled target material cooling system is placed into a vacuum furnace with a vacuum degree of 5*10 -2 Pa, a vacuum furnace control program is started, and vacuum brazing is completed in a gradient heating manner. After the vacuum brazing is completed, the target cooling system is immersed in machine oil at 90~100℃ for 1.5~2h, a current with a frequency of 50Hz and a density of 50~70mA / mm is introduced during the oil immersion process, and the target cooling system is dried under ultraviolet power of 25~30W for 5~10min after the oil immersion. S3, water pressure detection: The target cooling system obtained in step S2 is subjected to water pressure detection by using a water pressure detection device, the pressure leakage rate per minute is less than 0.1%, and the deformation amount is less than or equal to 5%.

2. A vacuum brazing process of a target cooling system according to claim 1, wherein, In step S2, the gradient temperature heating mode is: the temperature is raised to 345~355℃ within 35~40min, and the temperature is maintained for 20~30min; then the temperature is raised to 645~655℃ within 40~60min, and the temperature is maintained for 30~40min; then the temperature is raised to 965~975℃ within 40~60min, and the temperature is maintained for 30~40min; finally, the temperature is raised to 1045~1055℃ within 20~30min, and the temperature is maintained for 5~8min; after the temperature maintaining is completed, the power is turned off to cool the target cooling system with the furnace, nitrogen or argon is filled when the temperature drops to 595~605℃ to make the pressure value reach 60KPa, and the furnace is discharged when the temperature drops to 45~55℃.

3. A vacuum brazing process of a target cooling system according to claim 1, wherein In step S1, the nickel-based solder paste is BNi2 solder paste, and the thickness of the nickel-based solder paste applied to each position is 2~3mm.

4. A vacuum brazing process of a target cooling system according to claim 1, wherein In step S1, the weight is placed on the contact surface of the copper-chromium base plate (1) and the contact surface of the stainless steel nozzle (2) in a proportion of 95-105 g / cm 2 .

5. A vacuum brazing process of a target cooling system according to claim 1, wherein, In step S3, the water pressure detection mode is: the pressure is maintained for 25~35min under water pressure of 0.55~0.65MPa.

6. A vacuum brazing process of a target cooling system according to claim 1, wherein, In step S1, the cleaning mode is: ultrasonic cleaning in a 99% pure acetone solution for 25~40s, the ultrasonic frequency is 30~40KHz, and the ultrasonic power is 500~1500W.

7. A vacuum brazing process of a target cooling system according to claim 1, wherein In step S1, before the nickel-based solder paste is applied, each position requiring the application of the nickel-based solder paste is subjected to sand blasting treatment until the roughness of each position is 1.5~2.5μm.

8. A vacuum brazing process of a target cooling system according to claim 1, wherein, In step S1, the etching solution is composed of 5-15wt% hydrofluoric acid, 35-55wt% nitric acid, 5-15wt% fluosilicic acid, and the balance of water.

9. A vacuum brazing process of a target cooling system according to claim 1, wherein, In step S1, the activator is composed of sodium dodecyl sulfate, polydimethylsiloxane, and diphenylsilanediol in a mass ratio of 9:1:0.5-0.7.

Images