Plasma-assisted cold spraying device and method for repairing 2xxx aluminum alloy component through plasma heat-assisted cold spraying

Abstract

The invention discloses a plasma-assisted cold spraying device and a method for repairing a 2xxx aluminum alloy component through plasma heat-assisted cold spraying, and relates to a plasma-assisted cold spraying device and a method for repairing an aluminum alloy component through cold spraying. The method comprises the steps that a to-be-repaired area is preprocessed, the surface of the to-be-repaired area is pretreated, aluminum alloy powder and the to-be-sprayed area are synchronously heated through a plasma spray gun, and the aluminum alloy powder is deposited on the surface of a base body through a cold spraying device; a thermocouple is used for monitoring the temperature in real time, the distance between a plasma spray gun and a base body is adjusted based on temperature feedback, and the temperature is maintained to enable particles to be thermally softened without damaging the base body; and plasma heat treatment is carried out after spraying is completed. According to the method, the powder and the matrix are synchronously heated through the plasma heat source, the plastic deformation capacity and the interface bonding strength of particles are remarkably improved, the porosity and the internal residual stress of the coating are reduced, high-performance, large-thickness and low-heat-influence repair of the aluminum alloy is achieved, and the method is suitable for in-service repair of aviation aluminum alloy components.

Description

Technical Field

[0001] This invention relates to a plasma-assisted cold spraying device and a method for cold spraying repair of aluminum alloy components. Background Technology

[0002] 2xxx series aluminum alloys are aluminum alloys with Cu as the main alloying element. They include Al-Cu-Mg alloys, Al-Cu-Mg-Fe-Ni alloys, and Al-Cu-Mn alloys, among others. These alloys are heat-treatable aluminum alloys and occupy an irreplaceable and important position in the aerospace field. Their core advantages lie in their high specific strength, excellent heat resistance, and good machinability, enabling them to significantly reduce the structural weight of aircraft while meeting the stringent requirements for structural safety and service reliability of critical load-bearing components such as fuselage skin, stringers, and spacecraft tanks. However, in complex service environments, these components are prone to damage such as cracks, corrosion pits, and wear due to fatigue, corrosion, or foreign object impacts. If these damages are not repaired in a timely and effective manner, they will become stress concentration points, accelerating crack propagation, significantly weakening the structure's load-bearing capacity and fatigue life, and potentially leading to catastrophic consequences, directly threatening flight safety. Therefore, developing high-performance repair technologies for 2xxx series aluminum alloys is of great significance for restoring or even improving the original performance of components, extending their service life, reducing life-cycle costs, and ensuring the continuous safe operation of aerospace equipment.

[0003] To address this issue, effective remanufacturing repair measures are needed. Compared to traditional welding, thermal spraying, and plasma spraying techniques, cold spraying offers obvious advantages. Due to its low heat input, it has less thermal impact on the workpiece during the repair process, reducing the risk of deformation and cracking, and helping to maintain the original shape and structural stability of the workpiece. Furthermore, cold spraying technology offers flexible processing capabilities, allowing for precise control of the repair layer's thickness and shape, enabling accurate repair and remanufacturing of damaged areas of different sizes and shapes, thus improving the controllability of the repair effect. However, the cold spray repair layer is deposited through the plastic deformation of powder, resulting in a solid-phase bond; its bonding strength and performance still need improvement. Therefore, it is difficult to directly manufacture high-performance repair coatings using cold spraying.

[0004] CN117604513A discloses a method for preparing a high-strength aluminum alloy coating under cold conditions using cold spraying. This method promotes the dynamic precipitation of the second phase during the coating deposition process by preheating the substrate and controlling the cold spraying gas parameters. CN119640254A discloses a high-performance repair method for damaged aluminum alloy parts using dual-beam laser-assisted cold spraying. This method uses low-power-density laser to simultaneously assist cold spraying deposition, and then uses high-power-density laser to perform intermittent impact strengthening on the repair layer. Both methods aim to improve the performance of cold-sprayed aluminum alloy repair layers. However, CN117604513A mainly relies on indirect thermal assistance through substrate preheating and gas temperature, which has limited effect on the instantaneous softening of powder particles and the improvement of interfacial bonding strength. While CN119640254A introduces a laser heat source and strengthening method, its process system is complex, requiring two sets of laser equipment to work alternately, resulting in a cumbersome process and high cost, which is not conducive to on-site in-situ repair applications. CN119776821A discloses a method for cold-spraying a hard repair coating on ultra-high strength aluminum alloy. This method utilizes plasma arc light to perform online heat treatment on the substrate and coating during the cold spraying process. However, this method uses plasma arc light as a fixed-point heat source for continuous heating, resulting in concentrated heat input and a long treatment time. This can easily lead to localized overheating of the heat-sensitive material substrate, causing phase transformation and performance degradation. Summary of the Invention

[0005] To address the issues of weak adhesion and low performance in existing cold-sprayed hard repair coatings for aluminum alloys, this invention proposes a plasma-assisted cold spraying device and a method for plasma-assisted cold spraying repair of 2xxx aluminum alloy components. By simultaneously combining plasma jets with the cold spraying process, the device can clean the substrate surface, soften powder particles, and achieve efficient in-service repair of aerospace 2xxx aluminum alloys.

[0006] The plasma-assisted cold spraying device of the present invention consists of a Laval nozzle (3), a temperature measuring device (5), a clamping device (6), a slide rail (7), and a plasma spray gun (8). The Laval nozzle (3) is provided with an air inlet device (1) and a powder inlet device (2). The rear end of the plasma spray gun (8) is mounted on the slide rail (7). The clamping device (6) is provided with an alloy component (4) to be sprayed. The Laval nozzle (3) and the plasma spray gun (8) are located on one side of the alloy component (4) to be sprayed. The temperature measuring device (5) is located on the alloy component (4) to be sprayed. The clamping device (6) is a robotic arm. The temperature measuring device (5) is a thermocouple.

[0007] The present invention describes a method for repairing 2xxx aluminum alloy components using plasma-assisted cold spraying with a plasma-assisted thermal spraying device, comprising the following steps:

[0008] 1. Pre-process the area to be repaired of the 2xxx aluminum alloy component to obtain the aluminum alloy damaged component;

[0009] 2. The aluminum alloy defective component is fixed on the clamping device (6), and 2xxx aluminum alloy powder is added to the powder feeding device (2);

[0010] 3. Use a plasma spray gun (8) to preheat the area to be repaired in the aluminum alloy defective component;

[0011] During the preheating process, the current of the plasma spray gun (8) is 400-1000A and the output power is 16-40kW; the plasma spray gun (8) generates a plasma flame to continuously preheat the area to be sprayed.

[0012] 4. Using the air intake device (1) to deliver spraying gas to the Laval nozzle (3), and using the powder feeding device (2) to feed powder into the Laval nozzle (3), the Laval nozzle (3) performs cold spraying on the area to be sprayed. The 2xxx aluminum alloy powder undergoes plastic deformation and deposits on the area to be sprayed to form a repair coating. During the cold spraying process, the plasma spray gun (8) is used to synchronously heat the 2xxx aluminum alloy powder sprayed from the Laval nozzle (3) and the area to be sprayed. The distance between the plasma spray gun (8) and the aluminum alloy defective component is adjusted to control the temperature of the area to be sprayed to 400℃-500℃. When the temperature of the area to be sprayed is higher than 500℃, the plasma spray gun (8) is controlled to move away from the area to be sprayed along the slide rail (7). When the temperature is lower than 400℃, the plasma spray gun (8) is controlled to move closer to the area to be sprayed along the slide rail (7).

[0013] The cold spraying process is as follows: the angle between the spray jet generated by the Laval nozzle (3) and the area to be sprayed is 90°; the vertical distance between the Laval nozzle (3) and the area to be sprayed is 30-40mm; N2 with a pressure of 3-5MPa and a temperature of 500℃-600℃ is used as the spraying gas; the spraying trajectory is "S" shaped and the spacing between the spraying trajectories is 2-3mm; the moving speed of the Laval nozzle (3) is 150mm / s-200mm / s;

[0014] 5. After the cold spraying is completed, close the Laval nozzle (3) and continue to heat treat the formed repair coating with the plasma spray gun (8);

[0015] The heat treatment time is 120 seconds, and the temperature of the repair coating is controlled at 400℃-500℃.

[0016] The principles and beneficial effects of this invention are as follows:

[0017] This invention addresses the issue that the high hardness and strength of 2xxx series aluminum alloys necessitate more stringent thermodynamic conditions during powder deposition, leading to common problems such as weak interfacial bonding and high porosity in 2xxx series aluminum alloy coatings prepared using a single cold spraying process. By introducing a synchronous plasma heat source, this invention effectively solves the key problems of weak interfacial bonding and high porosity encountered in preparing 2xxx series aluminum alloy coatings using a single cold spraying process. The invention utilizes a plasma-assisted heating system to achieve precise and coordinated control of the temperature of the 2xxx series aluminum alloy particles and the substrate during cold spraying. This ensures that the particles are heated to a high thermal softening state (below the melting point) before impact, significantly improving the plastic deformation capacity of the aluminum alloy particles while strictly preventing particle melting, thus guaranteeing the solid-state deposition characteristics of the cold spraying technology. The controlled, instantaneous heating of the aluminum alloy powder and the area to be sprayed by plasma significantly reduces the yield strength of the material due to the thermal softening effect, allowing for more complete plastic deformation of the particles upon impact. This greatly promotes the bonding between the particles and the substrate, as well as among the particles themselves, enhancing the interfacial bonding strength. Meanwhile, the softening of particles by heat effectively fills the gaps between particles, and the subsequent impact compaction of particles achieves the densification of the coating, thereby significantly reducing the porosity and obtaining a dense coating with uniform structure and excellent performance.

[0018] Existing single-layer cold spraying methods, due to the accumulation of residual stress within the coating as the coating thickness increases, eventually lead to coating detachment, making it difficult to repair defects with large thicknesses. Therefore, the resulting 2xxx aluminum alloy deposits are relatively thin. This invention utilizes plasma-assisted cold spraying technology, enabling additive repair of 2xxx aluminum alloys. During plasma-assisted cold spraying, the high temperature of the plasma jet causes dynamic recovery of deformed particles, thereby reducing residual stress within the coating and achieving a large deposition thickness. This invention employs a combination of cold spraying and plasma-assisted techniques for defect repair. The temperature increase brought by plasma remains below the solidus of 2xxx aluminum alloys. Compared to traditional techniques, it does not involve high heat input and does not have a thermal impact on the substrate area. Therefore, it is highly suitable for in-situ repair of heat-sensitive materials such as aerospace aluminum alloys. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the plasma-assisted cold spraying device in Example 1;

[0020] Figure 2 Scanning electron microscope images of cross sections of the repair coatings obtained in Example 1 and Comparative Example 1;

[0021] Figure 3 This is a comparison diagram of the bonding strength of the repair coatings obtained in Example 1 and Comparative Example 1;

[0022] Figure 4 This is a comparison chart of the Vickers hardness of the repair coatings obtained in Example 1 and Comparative Example 1. Detailed Implementation

[0023] The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any reasonable combination of the specific embodiments.

[0024] Specific Implementation Method 1: The plasma-assisted cold spraying device in this implementation method consists of a Laval nozzle (3), a temperature measuring device (5), a clamping device (6), a slide rail (7), and a plasma spray gun (8). The Laval nozzle (3) is equipped with an air inlet device (1) and a powder inlet device (2). The rear end of the plasma spray gun (8) is mounted on the slide rail (7). The clamping device (6) is equipped with an alloy component (4) to be sprayed. The Laval nozzle (3) and the plasma spray gun (8) are located on one side of the alloy component (4) to be sprayed. The temperature measuring device (5) is located on the alloy component (4) to be sprayed. The clamping device (6) is a robotic arm. The temperature measuring device (5) is a thermocouple.

[0025] This embodiment has the following beneficial effects:

[0026] This embodiment employs plasma-assisted cold spraying technology. By introducing a synchronous plasma heat source, it effectively solves the key problems of weak interfacial bonding and high porosity encountered in the preparation of 2xxx series aluminum alloy coatings using single cold spraying. This embodiment utilizes a plasma-assisted heating system to achieve precise and coordinated control of the temperature of the 2xxx series aluminum alloy particles and the substrate during the cold spraying process. This ensures that the particles are heated to a relatively high thermal softening state (below the melting point) before impact, thereby significantly improving the plastic deformation capacity of the aluminum alloy particles. Simultaneously, it strictly prevents particle melting, ensuring the solid-state deposition characteristics of the cold spraying technology. The plasma provides controllable instantaneous heating to the aluminum alloy powder and the area to be sprayed. The resulting thermal softening effect significantly reduces the yield strength of the material, allowing the particles to undergo more complete plastic deformation upon impact. This greatly promotes the bonding between particles and the substrate, as well as among the particles themselves, enhancing the interfacial bonding strength. Simultaneously, the thermal softening of the particles effectively fills the voids between them, and the subsequent particle impact compaction achieves coating densification, thereby significantly reducing porosity and obtaining a dense coating with uniform structure and excellent performance.

[0027] This embodiment utilizes plasma-assisted cold spraying technology to achieve additive repair of 2xxx aluminum alloys. During the plasma-assisted cold spraying process, the high temperature of the plasma jet causes dynamic recovery of deformed particles, thereby reducing residual stress within the coating and achieving a large thickness deposition. This embodiment employs a combination of cold spraying and plasma-assisted technology for defect repair. The temperature increase brought by plasma remains below the solidus line of 2xxx aluminum alloys. Compared to traditional technologies, it does not involve high heat input and does not have a thermal impact on the substrate area. Therefore, it is highly suitable for in-situ repair of heat-sensitive material components such as aerospace aluminum alloys.

[0028] Specific Implementation Method Two: This implementation method utilizes a plasma-assisted cold spraying device for plasma-assisted hot spraying repair of 2xxx aluminum alloy components, and proceeds as follows:

[0029] 1. Pre-process the area to be repaired of the 2xxx aluminum alloy component to obtain the aluminum alloy damaged component;

[0030] 2. The aluminum alloy defective component is fixed on the clamping device (6), and 2xxx aluminum alloy powder is added to the powder feeding device (2);

[0031] 3. Use a plasma spray gun (8) to preheat the area to be repaired in the aluminum alloy defective component;

[0032] During the preheating process, the current of the plasma spray gun (8) is 400-1000A and the output power is 16-40kW; the plasma spray gun (8) generates a plasma flame to continuously preheat the area to be sprayed.

[0033] 4. Using the air intake device (1) to deliver spraying gas to the Laval nozzle (3), and using the powder feeding device (2) to feed powder into the Laval nozzle (3), the Laval nozzle (3) performs cold spraying on the area to be sprayed. The 2xxx aluminum alloy powder undergoes plastic deformation and deposits on the area to be sprayed to form a repair coating. During the cold spraying process, the plasma spray gun (8) is used to synchronously heat the 2xxx aluminum alloy powder sprayed from the Laval nozzle (3) and the area to be sprayed. The distance between the plasma spray gun (8) and the aluminum alloy defective component is adjusted to control the temperature of the area to be sprayed to 400℃-500℃. When the temperature of the area to be sprayed is higher than 500℃, the plasma spray gun (8) is controlled to move away from the area to be sprayed along the slide rail (7). When the temperature is lower than 400℃, the plasma spray gun (8) is controlled to move closer to the area to be sprayed along the slide rail (7).

[0034] The cold spraying process is as follows: the angle between the spray jet generated by the Laval nozzle (3) and the area to be sprayed is 90°; the vertical distance between the Laval nozzle (3) and the area to be sprayed is 30-40mm; N2 with a pressure of 3-5MPa and a temperature of 500℃-600℃ is used as the spraying gas; the spraying trajectory is "S" shaped and the spacing between the spraying trajectories is 2-3mm; the moving speed of the Laval nozzle (3) is 150mm / s-200mm / s;

[0035] 5. After the cold spraying is completed, close the Laval nozzle (3) and continue to heat treat the formed repair coating with the plasma spray gun (8);

[0036] The heat treatment time is 120 seconds, and the temperature of the repair coating is controlled at 400℃-500℃.

[0037] This embodiment addresses the issue that the high hardness and strength of 2xxx series aluminum alloys necessitate more stringent thermodynamic conditions during powder deposition. This results in common problems with 2xxx series aluminum alloy coatings prepared using a single cold spraying process, such as weak interfacial bonding and high porosity. By employing plasma-assisted cold spraying technology and introducing a synchronous plasma heat source, this key problem of weak interfacial bonding and high porosity encountered with single cold spraying of 2xxx series aluminum alloy coatings is effectively solved. This embodiment utilizes a plasma-assisted heating system to achieve precise and coordinated control of the temperature of the 2xxx series aluminum alloy particles and the substrate during cold spraying. This ensures that the particles are heated to a high thermal softening state (below the melting point) before impact, significantly improving the plastic deformation capacity of the aluminum alloy particles while strictly preventing particle melting, thus guaranteeing the solid-state deposition characteristics of the cold spraying technology. The controlled, instantaneous heating of the aluminum alloy powder and the area to be sprayed by plasma produces a thermal softening effect that significantly reduces the yield strength of the material, allowing for more complete plastic deformation of the particles upon impact. This greatly promotes the bonding between the particles and the substrate, as well as among the particles themselves, enhancing the interfacial bonding strength. Meanwhile, the softening of particles by heat effectively fills the gaps between particles, and the subsequent impact compaction of particles achieves the densification of the coating, thereby significantly reducing the porosity and obtaining a dense coating with uniform structure and excellent performance.

[0038] Existing single-layer cold spraying methods, due to the accumulation of residual stress within the coating as the coating thickness increases, eventually lead to coating detachment, making it difficult to repair defects with large thicknesses. Therefore, the resulting 2xxx aluminum alloy deposits are relatively thin. This embodiment utilizes plasma-assisted cold spraying technology, which enables additive repair of 2xxx aluminum alloys. During plasma-assisted cold spraying, the high temperature of the plasma jet causes dynamic recovery of deformed particles, thereby reducing residual stress within the coating and achieving a large deposition thickness. This embodiment employs a combination of cold spraying and plasma-assisted techniques for defect repair. The temperature increase brought by plasma remains below the solidus of 2xxx aluminum alloys. Compared to traditional techniques, it does not involve high heat input and does not have a thermal impact on the substrate area. Therefore, it is highly suitable for in-situ repair of heat-sensitive material components such as aerospace aluminum alloys.

[0039] Specific Implementation Method 3: This implementation method differs from Specific Implementation Method 2 in that the pre-processing described in step one is as follows: grinding, ultrasonic cleaning, drying and sandblasting are performed in sequence.

[0040] Specific Implementation Method Four: This implementation method differs from Specific Implementation Method Three in that the area to be sprayed is sanded with sandpaper.

[0041] Specific Implementation Method Five: This implementation method differs from Specific Implementation Method Three in that: ultrasonic cleaning uses anhydrous ethanol to remove surface oxide film and stains.

[0042] Specific Implementation Method Six: This implementation method differs from Specific Implementation Method Three in that: the roughness Sa of the area to be coated is not higher than 2.5 after sandblasting.

[0043] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Method Two in that: during the preheating treatment described in step three, the current of the plasma spray gun (8) is 800A and the output power is 32kW; the plasma spray gun (8) generates a plasma flame to continuously preheat the area to be sprayed.

[0044] Specific Implementation Method 8: The difference between this implementation method and Specific Implementation Method 2 is that the distance between the nozzle of the plasma spray gun (8) in step 4 and the area to be sprayed is 5cm-50cm.

[0045] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Method Two in that: the cold spraying process described in step four is as follows: the angle between the spray jet generated by the Laval nozzle (3) and the area to be sprayed is 90°; the vertical distance between the Laval nozzle (3) and the area to be sprayed is 30mm; N2 with a pressure of 5MPa and a temperature of 600℃ is used as the spraying gas; the spraying trajectory is "S" shaped and the spacing between the spraying trajectories is 2mm; the moving speed of the Laval nozzle (3) is 160mm / s.

[0046] Specific Implementation Method 10: This implementation method differs from Specific Implementation Method 2 in that the heat treatment time in step 5 is 120 seconds, and the temperature of the repair coating is controlled at 450°C.

[0047] Example 1

[0048] This embodiment of the plasma-assisted cold spraying device consists of a Laval nozzle (3), a temperature measuring device (5), a clamping device (6), a slide rail (7), and a plasma spray gun (8). The Laval nozzle (3) is equipped with an air inlet device (1) and a powder inlet device (2). The rear end of the plasma spray gun (8) is mounted on the slide rail (7). The clamping device (6) is equipped with an alloy component (4) to be sprayed. The Laval nozzle (3) and the plasma spray gun (8) are located on one side of the alloy component (4) to be sprayed. The temperature measuring device (5) is located on the alloy component (4) to be sprayed. The clamping device (6) is a robotic arm. The temperature measuring device (5) is a thermocouple. Figure 1 This is a schematic diagram of the plasma-assisted cold spraying device in Example 1.

[0049] This embodiment describes a method for repairing 2219 aluminum alloy components using plasma-assisted cold spraying with a plasma-assisted thermal spraying device, which is performed according to the following steps:

[0050] 1. Pre-process the area to be repaired of the 2219 aluminum alloy component to obtain the aluminum alloy damaged component;

[0051] The pre-processing is as follows: grinding, ultrasonic cleaning, drying and sandblasting are performed in sequence; the area to be sprayed is sanded with sandpaper; ultrasonic cleaning is performed with anhydrous ethanol to remove surface oxide film and stains; sandblasting is performed until the roughness Sa of the area to be sprayed is not higher than 2.5.

[0052] 2. The aluminum alloy defective component is fixed on the clamping device (6), and 2219 aluminum alloy powder is added to the powder feeding device (2);

[0053] 3. Use a plasma spray gun (8) to preheat the area to be repaired in the aluminum alloy defective component;

[0054] During the preheating process, the current of the plasma spray gun (8) is 800A and the output power is 32kW; the plasma spray gun (8) generates a plasma flame to continuously preheat the area to be sprayed.

[0055] 4. Using the air intake device (1) to deliver spraying gas to the Laval nozzle (3), and using the powder feeding device (2) to feed powder into the Laval nozzle (3), the Laval nozzle (3) performs cold spraying on the area to be sprayed. The 2219 aluminum alloy powder undergoes plastic deformation and deposits on the area to be sprayed to form a repair coating. During the cold spraying process, the plasma spray gun (8) is used to synchronously heat the 2219 aluminum alloy powder sprayed from the Laval nozzle (3) and the area to be sprayed. The distance between the plasma spray gun (8) and the aluminum alloy defective component is adjusted to control the temperature of the area to be sprayed to 400℃-500℃. When the temperature of the area to be sprayed is higher than 500℃, the plasma spray gun (8) is controlled to move away from the area to be sprayed along the slide rail (7). When the temperature is lower than 400℃, the plasma spray gun (8) is controlled to move closer to the area to be sprayed along the slide rail (7).

[0056] The distance between the nozzle of the plasma spray gun (8) and the area to be sprayed is 15cm; at this time, the temperature of the area to be sprayed is measured to be 450℃.

[0057] The cold spraying process is as follows: the angle between the spray jet generated by the Laval nozzle (3) and the area to be sprayed is 90°; the vertical distance between the Laval nozzle (3) and the area to be sprayed is 30mm; N2 with a pressure of 5MPa and a temperature of 600℃ is used as the spraying gas; the spraying trajectory is "S" shaped and the spacing between the spraying trajectories is 2mm; the moving speed of the Laval nozzle (3) is 160mm / s;

[0058] 5. After the cold spraying is completed, close the Laval nozzle (3) and continue to heat treat the formed repair coating with the plasma spray gun (8);

[0059] The heat treatment time is 120 seconds, and the temperature of the repair coating is controlled at 450°C.

[0060] Comparative Example 1

[0061] This comparative example uses a cold spraying device, which is a Laval nozzle (3). The Laval nozzle (3) is equipped with an air inlet device (1) and a powder inlet device (2).

[0062] The method for cold spraying repair of 2219 aluminum alloy components in this embodiment is carried out according to the following steps:

[0063] 1. Pre-process the area to be repaired of the 2219 aluminum alloy component to obtain the aluminum alloy damaged component;

[0064] The pre-processing is as follows: grinding, ultrasonic cleaning, drying and sandblasting are performed in sequence; the area to be sprayed is sanded with sandpaper; ultrasonic cleaning is performed with anhydrous ethanol to remove surface oxide film and stains; sandblasting is performed until the roughness Sa of the area to be sprayed is not higher than 2.5.

[0065] 2. Add 2219 aluminum alloy powder to the powder feeding device (2);

[0066] 3. Using the air intake device (1) to deliver spraying gas to the Laval nozzle (3), and using the powder feeding device (2) to feed powder into the Laval nozzle (3), the Laval nozzle (3) performs cold spraying on the area to be sprayed, and the 2219 aluminum alloy powder undergoes plastic deformation and deposits on the area to be sprayed to form a repair coating.

[0067] The cold spraying process is as follows: the angle between the spray jet generated by the Laval nozzle (3) and the area to be sprayed is 90°; the vertical distance between the Laval nozzle (3) and the area to be sprayed is 30mm; N2 with a pressure of 5MPa and a temperature of 600℃ is used as the spraying gas; the spraying trajectory is "S" shaped and the spacing between the spraying trajectories is 2mm; the moving speed of the Laval nozzle (3) is 160mm / s.

[0068] Figure 2 The images show scanning electron microscope (SEM) images of the cross sections of the repair coatings obtained in Example 1 and Comparative Example 1. The coating in Example 1 is denser and the substrate and coating are well bonded together, while the coating in Comparative Example 1 has more defects inside and at the interface between the coating and the substrate. Figure 3 The image shows a comparison of the bonding strength of the repair coatings obtained in Example 1 and Comparative Example 1. Compared with the single cold spraying in Comparative Example 1, the plasma-assisted cold spraying in Example 1 greatly improved the bonding strength of the 2219 aluminum repair coating. The bonding strength of the repair coating obtained in Example 1 was 43.32 MPa. Figure 4 This is a comparison chart of the Vickers hardness of the repair coatings obtained in Example 1 and Comparative Example 1. The 2219 aluminum repair coating prepared by plasma-assisted cold spraying in Example 1 has higher hardness, with a Vickers hardness of 111.2 HV.

Claims

1. A plasma-assisted cold spraying device, characterized in that: The plasma-assisted cold spraying device consists of a Laval nozzle (3), a temperature measuring device (5), a clamping device (6), a slide rail (7), and a plasma spray gun (8). The Laval nozzle (3) is equipped with an air inlet device (1) and a powder inlet device (2). The rear end of the plasma spray gun (8) is mounted on the slide rail (7). The clamping device (6) is equipped with an alloy component (4) to be sprayed. The Laval nozzle (3) and the plasma spray gun (8) are located on one side of the alloy component (4) to be sprayed. The temperature measuring device (5) is located on the alloy component (4) to be sprayed. The clamping device (6) is a robotic arm. The temperature measuring device (5) is a thermocouple.

2. A method for repairing 2xxx aluminum alloy components by plasma-assisted cold spraying using the plasma-assisted cold spraying device as described in claim 1, characterized in that: This method is performed in the following steps:

1. Pre-process the area to be repaired of the 2xxx aluminum alloy component to obtain the aluminum alloy damaged component; 2. The aluminum alloy defective component is fixed on the clamping device (6), and 2xxx aluminum alloy powder is added to the powder feeding device (2); 3. Use a plasma spray gun (8) to preheat the area to be repaired in the aluminum alloy defective component; During the preheating process, the current of the plasma spray gun (8) is 400-1000A and the output power is 16-40kW; the plasma spray gun (8) generates a plasma flame to continuously preheat the area to be sprayed.

4. Using the air intake device (1) to deliver spraying gas to the Laval nozzle (3), and using the powder feeding device (2) to feed powder into the Laval nozzle (3), the Laval nozzle (3) performs cold spraying on the area to be sprayed. The 2xxx aluminum alloy powder undergoes plastic deformation and deposits on the area to be sprayed to form a repair coating. During the cold spraying process, the plasma spray gun (8) is used to synchronously heat the 2xxx aluminum alloy powder sprayed from the Laval nozzle (3) and the area to be sprayed. The distance between the plasma spray gun (8) and the aluminum alloy defective component is adjusted to control the temperature of the area to be sprayed to 400℃-500℃. When the temperature of the area to be sprayed is higher than 500℃, the plasma spray gun (8) is controlled to move away from the area to be sprayed along the slide rail (7). When the temperature is lower than 400℃, the plasma spray gun (8) is controlled to move closer to the area to be sprayed along the slide rail (7). The cold spraying process is as follows: the angle between the spray jet generated by the Laval nozzle (3) and the area to be sprayed is 90°; the vertical distance between the Laval nozzle (3) and the area to be sprayed is 30-40mm; N2 with a pressure of 3-5MPa and a temperature of 500℃-600℃ is used as the spraying gas; the spraying trajectory is "S" shaped and the spacing between the spraying trajectories is 2-3mm; the moving speed of the Laval nozzle (3) is 150mm / s-200mm / s; 5. After the cold spraying is completed, close the Laval nozzle (3) and continue to heat treat the formed repair coating with the plasma spray gun (8); The heat treatment time is 120 seconds, and the temperature of the repair coating is controlled at 400℃-500℃.

3. The method for repairing 2xxx aluminum alloy components by plasma-assisted cold spraying using a plasma-assisted cold spraying device according to claim 2, characterized in that: The pre-processing described in step one consists of grinding, ultrasonic cleaning, drying, and sandblasting in sequence.

4. The method for repairing 2xxx aluminum alloy components by plasma-assisted thermal spraying using a plasma-assisted cold spraying device according to claim 3, characterized in that: Use sandpaper to sand the areas to be sprayed.

5. The method for repairing 2xxx aluminum alloy components by plasma-assisted thermal spraying using a plasma-assisted cold spraying device according to claim 3, characterized in that: Ultrasonic cleaning uses anhydrous ethanol to remove surface oxide films and stains.

6. The method for repairing 2xxx aluminum alloy components by plasma-assisted thermal spraying using a plasma-assisted cold spraying device according to claim 3, characterized in that: Sandblasting is performed until the surface roughness Sa of the area to be coated is no higher than 2.

5.

7. The method for repairing 2xxx aluminum alloy components by plasma-assisted thermal spraying using a plasma-assisted cold spraying device according to claim 2, characterized in that: During the preheating process described in step three, the current of the plasma spray gun (8) is 800A and the output power is 32kW; the plasma spray gun (8) generates a plasma flame to continuously preheat the area to be sprayed.

8. The method for repairing 2xxx aluminum alloy components by plasma-assisted thermal spraying using a plasma-assisted cold spraying device according to claim 2, characterized in that: The distance between the nozzle of the plasma spray gun (8) in step four and the area to be sprayed is 5cm-50cm.

9. The method for repairing 2xxx aluminum alloy components by plasma-assisted thermal spraying using a plasma-assisted cold spraying device according to claim 2, characterized in that: The cold spraying process described in step four is as follows: the angle between the spray jet generated by the Laval nozzle (3) and the area to be sprayed is 90°; the vertical distance between the Laval nozzle (3) and the area to be sprayed is 30mm; N2 with a pressure of 5MPa and a temperature of 600℃ is used as the spraying gas; the spraying trajectory is "S" shaped and the spacing between the spraying trajectories is 2mm; the moving speed of the Laval nozzle (3) is 160mm / s.

10. The method for repairing 2xxx aluminum alloy components by plasma-assisted thermal spraying using a plasma-assisted cold spraying device according to claim 2, characterized in that: The heat treatment time in step five is 120 seconds, and the temperature of the repair coating is controlled at 450°C.

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