Method for repairing sealing ring through laser-assisted cold spraying

Abstract

The invention discloses a method for repairing a sealing ring through laser-assisted cold spraying. The method comprises the steps that a base body of the sealing ring is pretreated; high-pressure cold spraying equipment is adopted for depositing copper-aluminum alloy powder on the to-be-repaired position, preheated through laser, of the base body, a repairing coating is formed on the to-be-repaired position of the base body, and the temperature of the to-be-repaired position of the base body is preheated to 300-1000 DEG C through laser; and carrying out post-treatment on the cold spraying deposition body. According to the method, firstly, the surface roughness of the base body is increased through a technical means, and then the plastic deformation degree of the surface of the sealing ring base body is increased through a laser-assisted technology, so that powder particles more easily impact the base body to form a sedimentary body, the bonding strength between a coating and the sealing ring is enhanced, and the sealing ring with few pores and without cracks is obtained; and the wear resistance and corrosion resistance of the repaired part are improved, and the service life of the sealing ring is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of sealing ring repair, and in particular to a method for repairing a sealing ring by laser-assisted cold spraying. Background Art

[0002] The sealing ring is a kind of seal installed between the bearing cover and the engine cover of the aircraft engine. It plays a sealing and protective role, which can prevent dust, water vapor, liquid, etc. in the atmosphere from entering the engine to ensure its normal operation. In addition, the sealing ring can also reduce air resistance, improve engine power performance, and improve fuel economy. Sealing rings are widely used in aircraft engines and can significantly improve engine performance. In actual processes, sealing rings are often worn and scratched, and the damaged parts need to be repaired before they can continue to be used.

[0003] The traditional repair method is complicated and requires completely grinding away the original coating before using laser cladding or plasma spraying for repair. During thermal spraying, due to the large thermal impact on the substrate, oxidation and phase change will occur. For easily oxidized copper metal alloys, uncontrollable changes will occur, causing deformation of the main material of the sealing ring.

[0004] Cold spray technology is a process that accelerates powder particles to supersonic speed and then deposits them on the substrate surface to form a coating by plastic deformation. However, in actual application, due to the low deposition efficiency, it is difficult to obtain a coating with high bonding strength while wasting materials. The repaired coating is very easy to crack or even fall off through the gaps and cracks inside the coating.

[0005] Therefore, there is an urgent need to develop a sealing ring repair method that can reduce the oxidation and phase change of the sealing ring, reduce the influence of uncontrollable factors, and at the same time ensure the bonding strength between the repair layer and the sealing ring matrix. Summary of the invention

[0006] The purpose of the present invention is to provide a method for repairing a sealing ring by laser-assisted cold spraying, which is beneficial to improving the bonding strength between the repair coating and the sealing ring substrate.

[0007] The present invention is achieved in that:

[0008] In a first aspect, the present invention provides a method for repairing a sealing ring by laser-assisted cold spraying, comprising:

[0009] Step A, pre-treating the surface of the sealing ring substrate;

[0010] Step B, using high pressure cold spraying equipment to deposit copper-aluminum alloy powder on the laser preheated substrate to be repaired position, forming a repair coating on the substrate to be repaired position, wherein the laser is used to preheat the substrate to be repaired position to a temperature of 300-1000°C.

[0011] Step C, post-processing the cold spray deposited body.

[0012] In an optional embodiment, the pretreatment includes removing rust, oil, oxide film, cracks and increasing roughness of the position to be repaired on the substrate;

[0013] And / or, the pretreatment includes at least one of sandblasting, laser cleaning and laser engraving; wherein the sandblasting material used in the sandblasting step is at least one of aluminum oxide, silicon dioxide, silicon nitride and diamond, and the average particle size of the sandblasting material is 20 to 30 μm.

[0014] In an optional embodiment, the high-pressure cold spraying equipment is a laser-assisted cold spraying equipment, which uses high-temperature and high-pressure gas to carry the copper-aluminum alloy powder in the chamber and deposit it on the position to be repaired on the substrate through a Laval nozzle;

[0015] And / or, the copper-aluminum alloy powder is a spherical powder, and the Cu content of the copper-aluminum alloy powder is 85%-95%, and the Al content is 5%-15%.

[0016] In an optional embodiment, the high pressure gas is selected from N 2 At least one of and He;

[0017] And / or, the diverging section and throat of the Laval nozzle are both spherical in shape.

[0018] In an optional embodiment, the temperature in the chamber is 600-1000°C, the rate at which the nozzle sprays the copper-aluminum alloy powder is 600-1200m / s, the powder feeding amount of the high-pressure cold spraying equipment is 100-400g / min, the distance from the nozzle to the position to be repaired on the substrate is 20-60mm, and the scanning speed of the nozzle is 100-600mm / s.

[0019] In an optional embodiment, the spot shape of the laser used for laser preheating is circular, elliptical or square;

[0020] and / or, the diameter of the laser beam is larger than the diameter of the copper-aluminum alloy powder beam ejected from the nozzle;

[0021] And / or, the laser used for laser preheating is Nd:YAG laser, CO2 laser or semiconductor laser;

[0022] In an optional embodiment, during laser preheating, the laser power of the laser is 2 kW to 4 kW, and the spot diameter is 2 mm to 12 mm;

[0023] In an optional embodiment, the center of the copper-aluminum alloy powder deposition coincides with the center of a spot of the laser;

[0024] And / or, the angle between the spray direction of the nozzle and the laser emitted by the laser is in the range of 15° to 60°.

[0025] In an optional embodiment, the post-treatment includes mechanical treatment and thermal treatment.

[0026] In an optional embodiment, the heat treatment includes: heating the repair coating to 300-500° C. in a vacuum atmosphere furnace, keeping the temperature for 3-5 hours, and then cooling in the furnace.

[0027] The present invention has the following beneficial effects:

[0028] In the present invention, laser is used to heat the sealing ring substrate to soften the substrate, thereby increasing the degree of plastic deformation of the substrate and enhancing the bonding strength between the coating and the sealing ring, thereby obtaining a sealing ring with few pores, no cracks, and a metallurgical bonding method, and the wear resistance and corrosion resistance of the repaired part are improved, obtaining excellent performance similar to that of a cast block, which is beneficial to improving the service life of the sealing ring. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0030] Figure 1 This is a schematic diagram of the overall equipment for laser-assisted cold spray repair of sealing rings;

[0031] Figure 2 This is a schematic diagram of the sealing ring structure after sandblasting and roughening;

[0032] Figure 3 A schematic diagram of the sealing ring structure after the repair coating is formed;

[0033] Figure 4 This is the metallographic structure of the coating in Example 1.

[0034] Illustration: 1-high pressure gas; 2-powder feeder; 3-heater; 4-chamber; 6-nozzle; 7-laser; 9-sealing ring; 10-damaged part; 12-repair coating. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0036] The embodiment of the present invention provides a method for repairing a sealing ring 9 by laser-assisted cold spraying, comprising:

[0037] Step A, pre-treating the surface of the sealing ring substrate;

[0038] Step B, using high pressure cold spraying equipment to deposit copper-aluminum alloy powder on the laser preheated substrate to be repaired position, forming a repair coating on the substrate to be repaired position, wherein the laser is used to preheat the substrate to be repaired position to a temperature of 300-1000°C.

[0039] Step C, post-processing the cold spray deposit. In the embodiment of the present invention, laser is used to heat the sealing ring 9 substrate to soften the substrate, increase the degree of plastic deformation of the substrate, enhance the bonding strength between the coating and the sealing ring 9, obtain a sealing ring 9 with few pores, no cracks, and high bonding, and improve the wear resistance and corrosion resistance of the repaired part, obtain excellent performance similar to that of the cast block, which is conducive to improving the service life of the sealing ring 9.

[0040] It should be noted that the use of laser to preheat the position of the substrate to be repaired is beneficial to increase the degree of plastic deformation of the substrate, and thus is beneficial to improving the density, uniformity and compactness of the repair coating 12. At the same time, it will also improve the bonding strength between the repair coating 12 and the sealing ring 9 substrate. However, too high a temperature may cause deformation of the sealing ring 9 substrate and degradation of the coating performance. Therefore, the temperature of the substrate to be repaired should not be too high.

[0041] In an optional embodiment, the pretreatment includes removing rust, oil, oxide film, cracks and increasing roughness of the position to be repaired on the substrate;

[0042] And / or, the pretreatment includes at least one of sandblasting, laser cleaning and laser engraving; wherein the sandblasting material used in the sandblasting step is at least one of aluminum oxide, silicon dioxide, silicon nitride and diamond, and the average particle size of the sandblasting material is 20 to 30 μm.

[0043] Before spraying, the substrate to be repaired is first derusted and degreased, and the cracks are removed; then sandblasting, laser cleaning and laser engraving are performed. The sandblasting step is to improve the roughness, cleanliness and adhesion of the substrate to be repaired, and at the same time can improve the absorption of the laser beam at the substrate to be repaired; the laser cleaning step can remove the oxide film of the substrate; the laser engraving step is mainly to increase the surface roughness of the substrate so that the powder particles are in full contact with the substrate surface.

[0044] In an optional embodiment, the high-pressure cold spraying equipment is a laser-assisted cold spraying equipment, which uses high-temperature and high-pressure gas to carry the copper-aluminum alloy powder in the chamber 4 and deposit it on the position to be repaired on the substrate through a Laval nozzle;

[0045] And / or, the copper-aluminum alloy powder is a vacuum gas atomized spherical powder, and the copper-aluminum alloy powder has a Cu content of 85%-95% and an Al content of 5%-15%.

[0046] Different types of nozzles 6 will have an impact on the acceleration and spraying effect of the particles.

[0047] In an optional embodiment, the high pressure gas 1 is selected from N 2 At least one of He and He; different gas types have different accelerating effects on particles. Helium has a small molecular weight and is easier to reach high speed, which is more conducive to improving the density of the repair coating 12.

[0048] In an optional embodiment, the expansion section and throat of the Laval nozzle 6 are both spherical in shape. Compared with a square shape, a spherical expansion section and throat are more conducive to improving the bonding force between the substrate to be repaired and the repair coating 12.

[0049] In an optional embodiment, the temperature in the chamber 4 is 600-1000°C, the rate at which the nozzle 6 sprays the copper-aluminum alloy powder is 600-1200m / s, the powder feeding amount of the high-pressure cold spraying equipment is 100-400g / min, the distance from the nozzle 6 to the position to be repaired on the substrate is 20-60mm, and the scanning speed of the nozzle 6 is 100-600mm / s.

[0050] The cold spraying parameters will affect the compactness of the repair coating 12 and the bonding strength between the repair coating 12 and the substrate, so they need to be reasonably selected. The spray gun and the workpiece form a certain angle to protect the workpiece and the spray gun from being bumped during operation, but the maximum angle between them should be less than the critical limit of spraying, that is, the angle between the spray gun and the workpiece is 35-65°.

[0051] In an optional embodiment, the spot shape of the laser used for laser preheating is circular, elliptical or square; preferably, compared with circular and elliptical spots, square spots are more conducive to improving the bonding strength between the repair coating 12 and the substrate, and ensuring the uniformity and density of the repair coating 12.

[0052] In an optional embodiment, the diameter of the laser beam is larger than the diameter of the copper-aluminum alloy powder beam ejected from the nozzle 6, so that the copper-aluminum alloy deposition positions can all be heated.

[0053] In an optional embodiment, the laser 7 used for laser preheating is a Nd:YAG laser 7, a CO2 laser 7 or a semiconductor laser 7.

[0054] In an optional embodiment, the laser power of the laser 7 is 2kW to 4kW, and the spot diameter is 2mm to 12mm during laser preheating; the laser power and spot diameter will affect the laser heating depth, heating speed, heating area size and temperature gradient of the position to be repaired on the substrate, thereby affecting the uniformity of the repair layer and the bonding strength between the repair layer and the substrate.

[0055] In an optional embodiment, the center of the copper-aluminum alloy powder deposition coincides with the center of a spot of the laser 7 , which is beneficial to improving the bonding strength between the repair coating 12 and the substrate.

[0056] In an optional embodiment, the angle between the spray direction of the nozzle 6 and the laser emitted by the laser 7 is in the range of 15° to 60°.

[0057] In an optional embodiment, the post-treatment includes mechanical treatment and thermal treatment.

[0058] The repair coating 12 is subjected to mechanical post-processing, for example, the repaired coating surface is ground and polished according to the actual application size to obtain the same structural shape as the original sealing ring 9, to obtain a repaired sealing ring 9, and to ensure that the repair layer has no peeling, delamination, etc.

[0059] In an optional embodiment, the heat treatment includes: heating the repair coating to 300-500° C. in a vacuum atmosphere furnace, keeping the temperature for 3-5 hours, and then cooling in the furnace.

[0060] Heat treatment can increase the density of the coating, and oxidation of the coating and the substrate should be avoided during the heat treatment process.

[0061] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0062] Example 1

[0063] This embodiment provides a method for repairing the sealing ring 9 by laser-assisted cold spraying, and the equipment used is as follows: Figure 1 As shown, the specific steps include:

[0064] (1) The damaged part 10 on the surface of the sealing ring 9 to be repaired is subjected to rust and oil removal treatment, and the cracked part is removed. Then, a sandblasting treatment is performed using silicon dioxide with an average particle size of 15 μm to obtain the following: Figure 2 The sealing ring 9 shown improves the absorption of the laser beam by the damaged part 10;

[0065] (2) A special copper-aluminum metal alloy powder is placed in a powder feeder 2, wherein the copper-aluminum alloy powder includes 7 wt% Al, and the remainder is Cu and inevitable impurities; after the high-pressure gas 1 passes through the heater 3, it drives the powder through the Laval nozzle 6 to achieve supersonic speed, and the powder particles are deposited on the damaged part 10 of the copper surface of the sealing ring 9, and a repair coating 12 is formed at the position to be repaired of the substrate preheated by the laser, such as Figure 3 As shown,

[0066] The high-pressure gas 1 is He, the expansion section and throat shape of the Laval nozzle 6 are both spherical, the temperature in the chamber 4 is 800°C, the nozzle 6 sprays the copper-aluminum alloy powder at a rate of 900m / s, the nozzle 6 is vertically arranged to the position of the substrate to be repaired, the powder feeding amount of the high-pressure cold spraying equipment is 250g / min, the distance from the nozzle 6 to the position of the substrate to be repaired is 40mm, and the scanning speed of the nozzle 6 is 350mm / s;

[0067] The temperature of the position to be repaired of the substrate is preheated to 650° C. by using laser, wherein the laser 7 used for laser preheating is a semiconductor laser 7; the spot shape of the laser used for laser preheating is square, the laser power is 7 kW, and the spot diameter is 7 mm; the beam diameter of the laser is larger than the diameter of the copper-aluminum alloy powder beam ejected from the nozzle 6;

[0068] The six-axis industrial robot is used to move the nozzle 6 and the laser 7 so that the center of the copper-aluminum alloy powder deposition coincides with the center of a spot of the laser 7. The angle between the spray direction of the nozzle 6 and the laser 7 is 35°.

[0069] (3) The repair coating is heated to 400° C. in a vacuum atmosphere furnace, kept at this temperature for 4 hours, and then cooled in the furnace; the repair coating 12 is then subjected to mechanical post-treatment to obtain a repaired sealing ring 9. The coating metallographic structure is as follows: Figure 4 shown.

[0070] Example 2

[0071] This embodiment provides a method for repairing the sealing ring 9 by laser-assisted cold spraying, and the equipment used is as follows: Figure 1 As shown, the specific steps include:

[0072] (1) The damaged part 10 on the surface of the sealing ring 9 to be repaired is subjected to rust and oil removal treatment, and the cracked part is removed. Then, a sandblasting treatment is performed using silicon dioxide with an average particle size of 20 μm to obtain the following: Figure 2 The sealing ring 9 shown improves the absorption of the laser beam by the damaged part 10;

[0073] (2) A special copper-aluminum metal alloy powder is placed in a powder feeder 2, wherein the copper-aluminum alloy powder includes 9wt% Al, and the remainder is Cu and inevitable impurities; after the high-pressure gas 1 passes through the heater 3, it drives the powder through the Laval nozzle 6 to achieve supersonic speed, and the powder particles are deposited on the damaged part 10 of the copper surface of the sealing ring 9, and a repair coating 12 is formed at the position to be repaired of the substrate preheated by the laser, wherein:

[0074] The high pressure gas 1 is selected from N 2 The expansion section and throat shape of the Laval nozzle 6 are both spherical, the temperature in the chamber 4 is 1000° C., the rate at which the nozzle 6 sprays the copper-aluminum alloy powder is 600 m / s, the nozzle 6 is vertically arranged to the position of the substrate to be repaired, the powder feeding amount of the high-pressure cold spraying equipment is 400 g / min, the distance from the nozzle 6 to the position of the substrate to be repaired is 60 mm, and the scanning speed of the nozzle 6 is 600 mm / s;

[0075] The temperature of the substrate to be repaired is preheated to 1000°C by laser, wherein the laser 7 used for laser preheating is CO 2 Laser 7; the spot shape of the laser used for laser preheating is square, the laser power is 6kW, and the spot diameter is 2mm; the beam diameter of the laser is larger than the diameter of the copper-aluminum alloy powder beam ejected from the nozzle 6;

[0076] The six-axis industrial robot is used to move the nozzle 6 and the laser 7 so that the center of the copper-aluminum alloy powder deposition coincides with the center of a spot of the laser 7. The angle between the spray direction of the nozzle 6 and the laser 7 is 60°.

[0077] (3) The repair coating is heated to 300° C. in a vacuum atmosphere furnace, kept at this temperature for 5 hours, and then cooled in the furnace; the repair coating 12 is then subjected to mechanical post-treatment to obtain a repaired sealing ring 9.

[0078] Example 3

[0079] This embodiment provides a method for repairing the sealing ring 9 by laser-assisted cold spraying, and the equipment used is as follows: Figure 1 As shown, the specific steps include:

[0080] (1) The damaged part 10 on the surface of the sealing ring 9 to be repaired is subjected to rust and oil removal treatment, and the cracked part is removed. Then, a sandblasting treatment is performed using silicon dioxide with an average particle size of 30 μm to obtain the following: Figure 2 The sealing ring 9 shown improves the absorption of the laser beam by the damaged part 10;

[0081] (2) A special copper-aluminum metal alloy powder is placed in a powder feeder 2, wherein the copper-aluminum alloy powder includes 5wt% Al, and the remainder is Cu and inevitable impurities; after the high-pressure gas 1 passes through the heater 3, it drives the powder through the Laval nozzle 6 to achieve supersonic speed, and the powder particles are deposited on the copper surface of the sealing ring 9 The position to be repaired 10 forms a repair coating 12 at the position to be repaired of the substrate preheated by the laser, wherein

[0082] The high-pressure gas 1 is selected from He, the expansion section and throat shape of the Laval nozzle 6 are both spherical, the temperature in the chamber 4 is 600°C, the nozzle 6 sprays the copper-aluminum alloy powder at a rate of 1200m / s, the nozzle 6 is vertically arranged to the position of the substrate to be repaired, the powder feeding amount of the high-pressure cold spraying equipment is 100g / min, the distance from the nozzle 6 to the position of the substrate to be repaired is 20mm, and the scanning speed of the nozzle 6 is 100mm / s;

[0083] The temperature of the position to be repaired of the substrate is preheated to 300° C. by using laser, wherein the laser 7 used for laser preheating is Nd:YAG laser 7; the spot shape of the laser used for laser preheating is square, the laser power is 5 kW, and the spot diameter is 12 mm; the beam diameter of the laser is larger than the diameter of the copper-aluminum alloy powder beam ejected from the nozzle 6;

[0084] The six-axis industrial robot is used to move the nozzle 6 and the laser 7 so that the center of the copper-aluminum alloy powder deposition coincides with the center of a spot of the laser 7. The angle between the spray direction of the nozzle 6 and the laser 7 is 15°.

[0085] (3) The repair coating is heated to 500° C. in a vacuum atmosphere furnace, kept at this temperature for 3 hours, and then cooled in the furnace; the repair coating 12 is then subjected to mechanical post-treatment to obtain a repaired sealing ring 9.

[0086] Example 4

[0087] This embodiment provides a method for laser-assisted cold spray repair of the sealing ring 9, which differs from Embodiment 1 mainly in that the laser power and preheating temperature are slightly lower, that is, the laser power is 5500W, and the laser is used to preheat the temperature of the substrate to be repaired to 400°C.

[0088] Example 5

[0089] This embodiment provides a method for laser-assisted cold spray repair of the sealing ring 9, which differs from Embodiment 1 mainly in that the laser power and preheating temperature are slightly higher, that is, the laser power is 4500W, and the laser is used to preheat the temperature of the substrate to be repaired to 800°C.

[0090] Comparative Example 1

[0091] This comparative example provides a method for laser-assisted cold spraying to repair the sealing ring 9 , which is different from Example 1 mainly in that the laser 7 is turned off and the sealing ring 9 is not preheated.

[0092] Comparative Example 2

[0093] This comparative example provides a method for laser-assisted cold spray repair of the sealing ring 9, which differs from Example 1 mainly in that the laser power and preheating temperature are too low, that is, the laser power is 2000W, and the laser is used to preheat the temperature of the substrate to be repaired to 200°C.

[0094] Comparative Example 3

[0095] This comparative example provides a method for laser-assisted cold spray repair of the sealing ring 9, which differs from Example 1 mainly in that the laser power and preheating temperature are too high, that is, the laser power is 10000W, and the laser is used to preheat the temperature of the substrate to be repaired to 900°C.

[0096] Comparative Example 4

[0097] This comparative example provides a method for repairing a sealing ring 9 by laser-assisted cold spraying, which is different from Example 1 mainly in that the expansion section and throat of the Laval nozzle 6 are both square in shape.

[0098] Comparative Example 5

[0099] This comparative example provides a method for laser-assisted cold spraying to repair a sealing ring 9. The main difference from Example 1 is that the cold spraying parameters are unreasonable, namely: the temperature in the chamber 4 is 800°C, the rate at which the nozzle 6 sprays the copper-aluminum alloy powder is 900m / s, the nozzle 6 is arranged vertically to the position of the substrate to be repaired, the powder feeding amount of the high-pressure cold spraying equipment is 250g / min, the distance from the nozzle 6 to the position of the substrate to be repaired is 40mm, and the scanning speed of the nozzle 6 is 350mm / s.

[0100] The crack conditions and bonding strength test methods of the sealing rings 9 repaired in the above embodiments and comparative examples refer to GB / T8642, and the coating porosity refers to ASTM E2109, and the results are shown in Table 1.

[0101]

[0102]

[0103] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for repairing a sealing ring by laser-assisted cold spraying, characterized in that: include: Step A, pre-treating the surface of the sealing ring substrate; Step B, using high pressure cold spraying equipment to deposit copper-aluminum alloy powder on the laser preheated substrate to be repaired position, forming a repair coating on the substrate to be repaired position, wherein the laser is used to preheat the substrate to be repaired position to a temperature of 300-1000° C.; Step C, post-processing the cold spray deposited body.

2. The method for repairing a sealing ring by laser-assisted cold spraying according to claim 1, characterized in that: The pretreatment includes removing rust, oil, oxide film, cracks and increasing roughness of the position to be repaired on the substrate; And / or, the pretreatment includes at least one of sandblasting, laser cleaning and laser engraving; wherein the sandblasting material used in the sandblasting step is at least one of aluminum oxide, silicon dioxide, silicon nitride and diamond, and the average particle size of the sandblasting material is 20 to 30 μm.

3. The method for repairing a sealing ring by laser-assisted cold spraying according to claim 1, characterized in that: The high-pressure cold spraying equipment is a laser-assisted cold spraying equipment, which uses high-temperature and high-pressure gas to carry the copper-aluminum alloy powder in the chamber and deposit it on the position to be repaired on the substrate through a Laval nozzle; And / or, the copper-aluminum alloy powder is a spherical powder, and the Cu content of the copper-aluminum alloy powder is 85%-95%, and the Al content is 5%-15%.

4. The method for repairing a sealing ring by laser-assisted cold spraying according to claim 1, characterized in that: The high pressure gas is selected from at least one of N2 and He; And / or, the diverging section and throat of the Laval nozzle are both spherical in shape.

5. The method for repairing a sealing ring by laser-assisted cold spraying according to claim 3, characterized in that: The temperature in the chamber is 600-1000° C., the rate at which the nozzle sprays the copper-aluminum alloy powder is 600-1200 m / s, the powder delivery rate of the high-pressure cold spraying equipment is 100-400 g / min, the distance from the nozzle to the position to be repaired on the substrate is 20-60 mm, and the scanning speed of the nozzle is 100-600 mm / s.

6. The method for repairing a sealing ring by laser-assisted cold spraying according to claim 1, characterized in that: The spot shape of the laser used for laser preheating is circular, elliptical or square; and / or, the diameter of the laser beam is larger than the diameter of the copper-aluminum alloy powder beam ejected from the nozzle; And / or, the laser used for laser preheating is Nd:YAG laser, CO2 laser or semiconductor laser.

7. The method for repairing a sealing ring by laser-assisted cold spraying according to claim 1, characterized in that: During laser preheating, the laser power of the laser is 2kW to 4kW, and the spot diameter is 2mm to 12mm.

8. The method for repairing a sealing ring by laser-assisted cold spraying according to claim 1, characterized in that: The center of the copper-aluminum alloy powder deposition coincides with the center of a laser spot; And / or, the angle between the spray direction of the nozzle and the laser emitted by the laser is in the range of 15° to 60°.

9. The method for repairing a sealing ring by laser-assisted cold spraying according to claim 1, characterized in that: The post-treatment includes mechanical treatment and thermal treatment.

10. The method for repairing a sealing ring by laser-assisted cold spraying according to claim 9, characterized in that: The heat treatment comprises: heating the repair coating to 300-500° C. in a vacuum atmosphere furnace, keeping the temperature for 3-5 hours, and then cooling it in the furnace.

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