An arc ion plating equipment cooling method and device

Abstract

The present invention provides a cooling method for an arc ion plating device for a niobium-tungsten alloy engine. By improving the cooling system in the furnace chamber of a vacuum cathodic arc deposition device, the problem of slow cooling rate of the coatings on the inner and outer surfaces of the combustion chamber of the niobium-tungsten alloy engine is solved. After molybdenum is plated on the workpiece surface by using the vacuum cathodic arc deposition technology, the cooling system is optimized so that the internal vacuum degree of the deposition device is maintained in dynamic balance, and the purpose of reducing the cooling time of the molybdenum layer at the body part is achieved by enhancing the convection effect of the molybdenum layer on the inner and outer surfaces of the combustion chamber. The present invention realizes for the first time the combination of a water cooling system and an air cooling system during the cooling process after molybdenum plating is completed on the inner and outer surfaces of the combustion chamber, improving the production efficiency of the attitude and orbit control engine.

Description

Technical Field

[0001] The present invention relates to a bi-propellant liquid propellant orbit and attitude control engine, and particularly to a cooling device and technology after molybdenum coating on the inner and outer surfaces of the thrust chamber body of a high-performance engine, which can be applied to the orbit and attitude control engines of space vehicles. Background Art

[0002] The bi-propellant liquid propellant orbit and attitude control engine is an important part of modern space vehicles and is widely used in orbit control, attitude adjustment, etc.

[0003] In recent years, with the development of aircraft, the requirements for engine performance have been continuously improved, requiring higher specific impulse and longer service life, so as to improve the orbit transfer efficiency and on-orbit life of aircraft or weapons. The allowable temperature of the engine is one of the main factors determining the specific impulse of the engine, while the performance of the matrix material of the engine thrust chamber body and its high-temperature oxidation-resistant coatings on the inner and outer surfaces determines the allowable temperature and service life of the engine.

[0004] At present, the matrix material of the thrust chamber body of the bi-propellant liquid propellant orbit and attitude control engine applied to the orbit injection and attitude control of space vehicles in China is niobium alloy, and the coating system is a silicon-chromium-titanium material system, and the main preparation method is slurry sintering method. The allowable temperature of the engine with this coating system does not exceed 1450 °C, and the service life does not exceed 25000 s.

[0005] In order to further improve the working temperature and service life of the engine nozzle, arc ion plating method is used to prepare ultra-high temperature protective coatings such as molybdenum and iridium, which can effectively improve the allowable temperature of the engine. However, its low production efficiency hinders the large-scale popularization and use of ultra-high temperature protective coatings. Summary of the Invention

[0006] The purpose of the present invention is to make up for the deficiencies in the prior art and provide an arc ion plating equipment cooling device and method. By adding a gas quenching and air cooling system to the furnace cavity of the vacuum cathodic arc deposition equipment, the problem of slow cooling rate of the coatings on the inner and outer surfaces of the niobium-tungsten alloy engine body is solved.

[0007] The above object of the present invention is mainly achieved by the following technical solutions: An arc ion plating equipment cooling method, in which the coating preparation process cools the coating preparation furnace wall and the target through a water cooling channel; it is characterized in that after the coating preparation on the inner and outer surfaces of the engine combustion chamber is completed in sequence, the following cooling treatments are performed:

[0008] After the coating preparation on the inner / outer surface of the engine combustion chamber is completed, it is cooled to 500 °C - 900 °C with the water cooling channel in the open state;

[0009] Introduce a protective gas into the coating preparation furnace, turn on the fan inside the furnace, and control the flow rate of the inlet gas and the amount of the extracted gas so that the air pressure inside the furnace fluctuates within the range of 1×10 0 ~1×10 -3 ;

[0010] When the surface temperature of the engine combustion chamber reaches 30 - 60 °C, stop introducing the protective gas, turn off the fan, and complete the cooling.

[0011] Preferably, on the basis of water - cooling, a stepped air - cooling method is used for cooling. In different temperature ranges, the maintained range of the air pressure inside the furnace is different. The stepped air - cooling method ensures the rapid cooling of the workpiece and has a relatively small impact on the film layer quality.

[0012] Preferably, when the workpiece temperature is between 700 - 900 °C, adjust the fan speed gear to the low - speed gear, and adjust the gas flow rate so that the air pressure inside the furnace fluctuates within the range of 1×10 -2 ~1×10 -3 ; when the workpiece temperature is between 500 - 700 °C, adjust the fan speed gear to the medium - speed gear, and adjust the gas flow rate so that the air pressure inside the furnace fluctuates within the range of 1×10 -1 ~1×10 -3 ; when the workpiece temperature is below 500 °C, adjust the fan speed gear to the high - speed gear, and adjust the gas flow rate so that the air pressure inside the furnace fluctuates within the range of 1×10 0 ~1×10 -2 .

[0013] Preferably, the coating of the engine combustion chamber is prepared by vacuum cathodic arc deposition technology. The combustion chamber matrix material is niobium alloy, and the coating material is molybdenum or iridium.

[0014] Preferably, the inner hole diameter of the engine combustion chamber is 4 - 100 mm, the outer diameter is 4 - 110 mm, and the combustion chamber length is 5 - 300 mm; the coating thickness does not exceed 300 μm.

[0015] A cooling device applicable to the cooling method of the arc ion plating equipment includes a protective gas passage, a workpiece real - time temperature monitoring device, a flow control device for the protective gas, and an adjustable - speed fan;

[0016] A protective gas passage is arranged above the coating preparation furnace and is connected to a gas cylinder through the flow control device for the protective gas; the engine combustion chamber is placed on the workbench inside the coating preparation furnace, and the workpiece real - time temperature monitoring device is installed through the coating preparation furnace for detecting the surface temperature of the engine combustion chamber during the cooling process; the adjustable - speed fan is placed inside the coating preparation furnace and, together with the flow control device for the protective gas, maintains the air pressure inside the furnace within the range of 1×10 0 ~1×10 -3Fluctuate within a range.

[0017] Preferably, the real-time temperature monitoring device for the workpiece includes a thermocouple installed on the structural member and a transmission and control mechanism equipped with an isolation baffle. The position of the thermocouple faces the straight section of the engine combustion chamber. During the preparation of the workpiece coating, the isolation baffle isolates the thermocouple, and during the cooling of the workpiece, the isolation baffle is withdrawn, and the thermocouple works normally, effectively protecting the device from being affected by the coating.

[0018] Preferably, the position of the thermocouple satisfies that after the engine combustion chamber is inverted up and down, it faces the position between the lower part of the nozzle outlet and the throat.

[0019] Preferably, the flow control device for the protective gas includes a gas input and output device, a gas flow controller, a gas channel isolation plate, and a control system. The gas input and output device is used to supply the protective gas to the protective gas channel and to recover the gas in the coating preparation furnace. The gas flow controller controls the gas flow in the protective gas channel. The gas channel isolation plate is used to cut off the protective gas channel and the coating preparation furnace during coating preparation and to open the protective gas channel during cooling. The control system is used to control the gas input and output device, the gas flow controller, and the gas channel isolation plate.

[0020] The present invention has the following beneficial effects compared with the prior art:

[0021] The present invention designs a cooling device and method for an arc ion plating equipment for the niobium-tungsten alloy combustion chamber of a bi-propellant liquid rocket engine. By adding a gas quenching and air cooling technology in the furnace cavity of the vacuum cathodic arc deposition equipment in addition to the water cooling device, the problem of slow cooling after the coating of the inner and outer surfaces of the niobium-tungsten alloy combustion chamber is solved. After the deposition is completed under the corresponding deposition process of the vacuum cathodic arc deposition, the cooling parameters after the coating deposition are optimized, and the thickness of the molybdenum layer deposited is within 300 μm, the coating is smooth, dense, has good adhesion, and has no obvious color difference or color spot.

[0022] The present invention controls the flow rate of the protective gas introduced through the cooling device, can control and adjust the cooling speed of the workpiece surface to a certain extent, and realizes the rapid cooling of the workpiece after molybdenum plating while preparing a molybdenum coating with a smooth, dense surface and good adhesion on the inner and outer surfaces of the combustion chamber.

[0023] The present invention first proposes a preparation method of introducing a protective gas for cooling by a water circuit system and a gas quenching and air cooling system after the molybdenum layer is deposited by arc ion plating. This preparation method will shorten the cooling time by 1-5 hours and increase the production efficiency by 2-6 times, which helps to promote the popularization and application of coatings such as molybdenum and iridium, and promotes the rapid development of surface protection coatings for attitude and orbit control engines.

[0024] Tests have shown that this cooling method is applicable to the cooling of combustion chambers with an inner hole diameter of 4 - 100 mm, an outer diameter of 4 - 110 mm, and a combustion chamber length of 5 - 300 mm. The cooling time for each process step is reduced by 1 - 5 hours, improving production efficiency and solving the problem of slow cooling after coating the inner and outer surfaces of the combustion chamber. Description of the Drawings

[0025] Figure 1 Schematic Diagram of Niobium-Tungsten Alloy Combustion Chamber

[0026] Figure 2 Cooling Device Diagram for the Inner Surface of the Combustion Chamber after Arc Deposition

[0027] Figure 3 Cooling Device Diagram for the Outer Surface of the Combustion Chamber after Arc Deposition Detailed Implementation Manner

[0028] The present invention will be further described in detail below with reference to the drawings and specific embodiments:

[0029] A cooling method for an arc ion plating equipment of the present invention includes the following steps:

[0030] First step: After the deposition of the coating on the inner surface of the engine combustion chamber is completed, it is naturally cooled.

[0031] Inner and outer surface metal cathode targets are processed according to the shape and size of the niobium-tungsten alloy combustion chamber and degreased; the inner and outer surfaces of the qualified engine combustion chamber are degreased and pickled, and after ultrasonic cleaning, they are ready for coating deposition; the cleaned engine combustion chamber is placed on the product table, keeping the inner surface of the combustion chamber and the target on the same center, while avoiding contact between the target and the product, as Figure 2 shown; the vacuum system 4 is used to evacuate to below 1×10 -2 Pa, and a molybdenum layer is deposited according to the corresponding process parameters. After the deposition is completed, the nozzle is cooled.

[0032] During the coating preparation process, the original water-cooling channels in the coating preparation equipment (generally used to cool the target and the furnace wall) are always in the open state. After the molybdenum coating is deposited on the inner and outer surfaces of the combustion chamber, the workpiece is in a high-temperature state. The real-time temperature measuring device monitors the temperature of the workpiece, so that the workpiece is naturally cooled to 500°C - 900°C in the high-vacuum state of the original coating preparation, avoiding the generation of large internal stresses inside the coating and causing phenomena such as peeling and cracking of the coating.

[0033] Second step: Turn on the gas quenching and air cooling device to accelerate the cooling of the workpiece.

[0034] Wait for the workpiece to cool naturally to 500°C - 900°C under high vacuum, turn on the protective gas flow control device to introduce protective gas (such as argon), adjust the fan. When the amount of gas introduced reaches a certain balance with the amount of gas pumped out by the mechanical pump - molecular pump two - stage pump vacuum system, keep the furnace pressure fluctuating within the range of 1×10 0 ~1×10 -3 range.

[0035] Research has found that: when the workpiece temperature is between 700 - 900°C, adjust the fan speed to the low - speed gear, and adjust the gas flow to make the furnace pressure fluctuate within the range of 1×10 -2 ~1×10 -3 range; when the workpiece temperature is between 500 - 700°C, adjust the fan speed to the medium - speed gear, and adjust the gas flow to make the furnace pressure fluctuate within the range of 1×10 -1 ~1×10 -3 range; when the workpiece temperature is below 500°C, adjust the fan speed to the high - speed gear, and adjust the gas flow to make the furnace pressure fluctuate within the range of 1×10 0 ~1×10 -2 range. Under this cooling condition, the cooling speed of the workpiece is relatively fast, and the influence on the film layer quality is relatively small.

[0036] Step 3: Stop introducing protective gas and prepare for taking the workpiece out of the furnace

[0037] When the surface temperature of the workpiece reaches 30 - 60°C, stop the protective gas passage, turn off the fan, and close each stage of the vacuum system step - by - step according to the operation requirements. The molybdenum layer cooling is completed, and the workpiece is taken out of the furnace for inspection.

[0038] Step 4: Treatment of the outer surface of the engine combustion chamber

[0039] Place the cleaned engine combustion chamber vertically on the product platform as Figure 3 shown. Vacuum the vacuum chamber to below 1×10 -2 Pa, deposit a molybdenum layer on the outer surface of the workpiece according to the corresponding process parameters. After the deposition is completed, cool the nozzle.

[0040] After the molybdenum coating is deposited on the outer surface of the combustion chamber, monitor the workpiece temperature through a real - time temperature measuring device. When the workpiece cools naturally to 500°C - 900°C under high vacuum, turn on the protective gas flow control device to introduce protective gas (such as argon), adjust the fan to the corresponding wind speed state, and keep the furnace pressure fluctuating within the range of 1×10 0 ~1×10 -3 range. When the surface temperature of the workpiece reaches 30 - 60°C, close the protective gas passage, turn off the fan and the water - cooling passage, and close each stage of the vacuum system step - by - step according to the operation requirements. The molybdenum layer cooling is completed, and the workpiece is taken out of the furnace for inspection.

[0041] Inspect the surface quality of the workpiece after it comes out of the furnace to ensure that the coating is smooth, dense, has good adhesion, and has no obvious color difference or color spot.

[0042] The present invention provides a cooling device applicable to the above cooling method. Figure 2 Cooling device diagram for the inner surface of the combustion chamber after arc deposition. After the molybdenum layer deposition is completed, start this cooling device together with the water cooling device to accelerate the cooling of the workpiece. Figure 3 Cooling device diagram for the outer surface of the combustion chamber after arc deposition. After the molybdenum layer deposition is completed, start this cooling device together with the water cooling channel to accelerate the cooling of the workpiece. This cooling device includes a protective gas channel 1, a workpiece real-time temperature monitoring device 3, a flow control device 2 for the protective gas, and a variable-speed fan 7, etc.

[0043] A protective gas channel is arranged above the coating preparation furnace and is connected to a gas cylinder through a flow control device for the protective gas; the engine combustion chamber is placed on the workbench inside the coating preparation furnace, and the workpiece real-time temperature monitoring device is installed through the coating preparation furnace for detecting the surface temperature of the engine combustion chamber during the cooling process; the variable-speed fan is placed inside the coating preparation furnace and, together with the flow control device for the protective gas, maintains the air pressure inside the furnace within the range of 1×10 0 ~1×10 -3 during the cooling process.

[0044] The workpiece real-time temperature monitoring device includes a thermocouple installed on the structural member and a transmission and control mechanism equipped with an isolation baffle 9. The position of the thermocouple faces the straight section of the engine combustion chamber; during the workpiece coating preparation process, the isolation baffle isolates the thermocouple, and during the workpiece cooling process, the isolation baffle is withdrawn and the thermocouple works normally, effectively protecting this device from being affected by the coating. In a preferred example given by the present invention, the position of the thermocouple satisfies that after the engine combustion chamber is inverted up and down, it faces the position between the lower part of the nozzle outlet and the throat.

[0045] The flow control device for the protective gas includes a gas input and output device, a gas flow controller, a gas channel isolation plate, and a control system; the gas input and output device is used to supply the protective gas to the protective gas channel and to recover the gas in the coating preparation furnace; the gas flow controller controls the gas flow in the protective gas channel; the gas channel isolation plate is used to cut off the protective gas channel and the coating preparation furnace during coating preparation and to open the protective gas channel during cooling; the control system is used to control the gas input and output device, the gas flow controller, and the gas channel isolation plate.

[0046] Note: Generally, a small industrial fan with three gears of high, medium, and low can be selected for the equipment used, which can meet the equipment requirements.

[0047] Example 1

[0048] To manufacture a niobium-tungsten alloy engine combustion chamber with dimensions of ( being the minimum inner diameter of the combustion chamber and 70 mm being the total length of the combustion chamber) as an example, Figure 1 The figure shows a schematic diagram of a niobium-tungsten alloy engine combustion chamber. A molybdenum coating is deposited on the inner and outer surfaces of the combustion chamber to illustrate the specific implementation method of the present invention.

[0049] 1. Preparation stage of the niobium-tungsten alloy engine combustion chamber and target

[0050] According to the drawing requirements of the engine combustion chamber, the combustion chamber is machined The inner and outer surfaces of the engine combustion chamber are degreased and derusted, waiting for the deposition of the coating; the inner and outer surface metal cathode targets are machined according to the shape and size of the niobium-tungsten alloy combustion chamber, and they are degreased and cleaned.

[0051] 2. Preparation of molybdenum coating on the inner surface of the niobium-tungsten alloy engine combustion chamber

[0052] Place the cleaned engine combustion chamber on the product table, keeping the inner surface of the combustion chamber and the target on the same center, while avoiding contact between the target and the product, as Figure 2 shown. Turn on the water cooling channel 8, and evacuate the vacuum chamber to below 1×10 -2 Pa through the vacuum system 4. Control the arc source system 5 and the operation system 6 to start depositing the molybdenum layer. The process parameters are: the starting arc current is 80 A, the arc voltage is 30 V, and the deposition time is 8 min. After the deposition is completed, the thickness of the deposited molybdenum coating is 50±15 μm.

[0053] After the molybdenum coating is deposited on the inner surface of the combustion chamber, monitor the workpiece temperature through the real-time temperature measuring device 3. When the workpiece naturally cools to below 850 °C in a high vacuum state, turn on the protective gas flow control device 2 to introduce the protective gas, and adjust the fan 7 to a lower wind speed state to keep the furnace pressure fluctuating within the range of 1×10 -2 ~1×10 -3 ; when the workpiece temperature is 680 °C, adjust the wind speed gear of the fan to the medium speed gear, and adjust the gas flow to keep the furnace pressure fluctuating within the range of 1×10 -1 ~1×10 -3 ; when the workpiece temperature is 450 °C, adjust the wind speed gear of the fan to the high speed gear, and adjust the gas flow to keep the furnace pressure fluctuating within the range of 1×10 0 ~1×10 -2 as Figure 2 shown. When the surface temperature of the workpiece reaches 45 °C, stop the protective gas channel 1, turn off the fan 7 and the water cooling channel 8, close each stage of the vacuum system according to the operation requirements in stages, and the molybdenum layer cooling is completed, and the workpiece is taken out of the furnace for inspection.

[0054] 3. Preparation of Molybdenum Coating on the Outer Surface of the Combustion Chamber of Niobium-Tungsten Alloy Engine

[0055] Place the combustion chamber after the inner surface deposition is completed on the product table, as Figure 3 shown. Evacuate to below 1×10 -2 Pa, and start depositing the molybdenum layer. The process parameters are: the starting arc current is 100 A, the arc voltage is 30 V, and the deposition time is 3 h. After the deposition is completed,

[0056] the thickness of the deposited molybdenum coating is 50±15 μm.

[0057] After the molybdenum coating is deposited on the outer surface of the combustion chamber, monitor the workpiece temperature through the real-time temperature measurement device 3. When the workpiece naturally cools to below 800 °C in a high-vacuum state, turn on the protective gas flow control device 2 to introduce the protective gas, and adjust the fan 7 to a lower wind speed state to keep the furnace pressure fluctuating within the range of 1×10 0 ~1×10 -3 ; when the workpiece temperature is 630 °C, adjust the wind speed gear of the fan to the medium speed gear, and adjust the gas flow to keep the furnace pressure fluctuating within the range of 1×10 -1 ~1×10 -3 ; when the workpiece temperature is 480 °C, adjust the wind speed gear of the fan to the high speed gear, and adjust the gas flow to keep the furnace pressure fluctuating within the range of 1×10 0 ~1×10 -2 , as Figure 3 shown. When the surface temperature of the workpiece reaches 45 °C, stop the protective gas passage, turn off the fan and the water-cooling passage, close each stage of the vacuum system step by step according to the operation requirements, the molybdenum layer cooling is completed, and the workpiece is taken out of the furnace for inspection.

[0058] 4. Inspection

[0059] The prepared molybdenum layer is dense and has good adhesion. The thickness of the molybdenum layer is detected by the mechanical measurement method, and the coating thickness meets the technical requirements.

[0060] The test shows that: this preparation and cooling technology realizes the deposition of molybdenum coatings on the inner and outer surfaces of the combustion chamber of the niobium-tungsten alloy engine with a size of ; the thickness of the deposited coating: 50±15 μm; the cooling time is reduced by 2 - 3 h; the coating thickness uniformity is good, and the coating is dense and has good adhesion.

[0061] Example 2

[0062] To manufacture a combustion chamber of a niobium-tungsten alloy engine with a size of ( Taking the minimum inner diameter of the combustion chamber as [ID=], and the total length of the combustion chamber as 20 mm as an example, molybdenum coatings are deposited on the inner and outer surfaces of the combustion chamber to illustrate the specific implementation method of the present invention.

[0063] 1. Preparation stage of the combustion chamber and target of niobium-tungsten alloy engine

[0064] According to the drawing requirements of the engine combustion chamber, the combustion chamber is processed. Degrease and remove rust from the inner and outer surfaces of the engine combustion chamber, and wait for coating deposition; process the inner and outer surface metal cathode targets according to the shape and size of the niobium-tungsten alloy combustion chamber, and degrease and clean them.

[0065] 2. Preparation of molybdenum coating on the inner surface of the niobium-tungsten alloy engine combustion chamber

[0066] Place the cleaned engine combustion chamber on the product table, keep the inner surface of the combustion chamber and the target on the same center of the circle, and at the same time avoid contact between the target and the product, as Figure 2 shown. Open the water-cooling channel, evacuate the vacuum chamber to below 1×10 -2 Pa, and start depositing the molybdenum layer. The process parameters are: the starting arc current is 60 A, the arc voltage is 30 V, and the deposition time is 5 min. After the deposition is completed, the thickness of the deposited molybdenum coating is 50±15 μm.

[0067] After the molybdenum coating is deposited on the inner surface of the combustion chamber, monitor the workpiece temperature through a real-time temperature measurement device. When the workpiece naturally cools to below 800 °C in a high-vacuum state, turn on the protective gas flow control device to introduce the protective gas, and adjust the fan to a lower wind speed state to keep the furnace pressure fluctuating within the range of 1×10 -2 ~1×10 -3 ; when the workpiece temperature is 600 °C, adjust the wind speed gear of the fan to the medium speed gear, and adjust the gas flow to keep the furnace pressure fluctuating within the range of 1×10 -1 ~1×10 -3 ; when the workpiece temperature is 400 °C, adjust the wind speed gear of the fan to the high speed gear, and adjust the gas flow to keep the furnace pressure fluctuating within the range of 1×10 0 ~1×10 -2 . When the surface temperature of the workpiece reaches 45 °C, stop the protective gas channel, turn off the fan and the water-cooling channel, close each stage of the vacuum system step by step according to the operation requirements, the molybdenum layer cooling is completed, and the workpiece is taken out of the furnace for inspection.

[0068] 3. Preparation of molybdenum coating on the outer surface of the niobium-tungsten alloy engine combustion chamber

[0069] Place the combustion chamber after the inner surface deposition on the product table, as Figure 3 shown. Evacuate to 1×10 -2Below Pa, start depositing the molybdenum layer. The process parameters are an arc starting current of 80 A, an arc voltage of 30 V, and a deposition time of 1.5 h. After the deposition is completed, the thickness of the molybdenum coating is 50 ± 15 μm.

[0070] After the molybdenum coating is deposited on the outer surface of the combustion chamber, monitor the workpiece temperature through a real-time temperature measurement device. When the workpiece naturally cools to below 840 °C in a high vacuum state, turn on the protective gas flow control device 2 to introduce the protective gas, and adjust the fan 7 to a lower wind speed state so that the furnace pressure remains within the range of 1×10 0 ~1×10 -3 When the workpiece temperature is 600 °C, adjust the wind speed gear of the fan to the medium speed gear, and adjust the gas flow so that the furnace pressure fluctuates within the range of 1×10 -1 ~1×10 -3 When the workpiece temperature is 450 °C, adjust the wind speed gear of the fan to the high speed gear, and adjust the gas flow so that the furnace pressure fluctuates within the range of 1×10 0 ~1×10 -2 When the surface temperature of the workpiece reaches 45 °C, stop the protective gas passage, turn off the fan and the water cooling passage, close each stage of the vacuum system step by step according to the operation requirements, the molybdenum layer cooling is completed, and the workpiece is taken out of the furnace for inspection.

[0071] 4. Inspection

[0072] The prepared molybdenum layer is dense and has good adhesion. The thickness of the molybdenum layer is detected by mechanical measurement method, and the coating thickness meets the technical requirements.

[0073] The test shows that: the preparation and cooling technology realizes the deposition of molybdenum coatings on the inner and outer surfaces of the niobium-tungsten alloy engine combustion chamber with a size of The deposited coating thickness is: 50 ± 15 μm;; the cooling time is reduced by 2 - 3 h; the coating thickness uniformity is good, and the coating is dense and has good adhesion.

[0074] As described above, only the best specific implementation mode of the present invention is described, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

[0075] The content not detailedly described in the specification of the present invention belongs to the well-known technology of those skilled in the art.

Claims

1. A cooling method for an arc ion plating equipment, wherein the furnace wall and the target are cooled through a water cooling channel during the coating preparation process; characterized in that After the coatings on the inner and outer surfaces of the engine combustion chamber are prepared in sequence, the following cooling treatment is carried out. The engine combustion chamber is a niobium-tungsten alloy combustion chamber of a bi-propellant liquid rocket engine: After the coating on the inner / outer surface of the engine combustion chamber is prepared, it is cooled to 500°C to 900°C with the water cooling channel in the open state; Introduce a protective gas into the coating preparation furnace, turn on the furnace fan, and control the flow rate of the inlet gas and the amount of the extracted gas so that the furnace pressure fluctuates within the range of 1×10 0 ~1×10 -3 ; When the surface temperature of the engine combustion chamber reaches 30 to 60°C, the supply of the protective gas is stopped, the fan is turned off, and the cooling is completed; Based on water-cooling for temperature reduction, a stepped air-cooling method is adopted for temperature reduction. In different temperature ranges, the maintained range of the furnace internal pressure is different. The stepped air-cooling method ensures the rapid cooling of the workpiece and has a relatively small impact on the coating quality. When the workpiece temperature is between 700 - 900 °C, the fan speed gear is adjusted to the low-speed gear, and the gas flow rate is adjusted to make the furnace internal pressure fluctuate within the range of 1×10 -2 ~1×10 -3 ; when the workpiece temperature is between 500 - 700 °C, the fan speed gear is adjusted to the medium-speed gear, and the gas flow rate is adjusted to make the furnace internal pressure fluctuate within the range of 1×10 -1 ~1×10 -3 ; when the workpiece temperature is below 500 °C, the fan speed gear is adjusted to the high-speed gear, and the gas flow rate is adjusted to make the furnace internal pressure fluctuate within the range of 1×10 0 ~1×10 -2 . The coating of the engine combustion chamber is prepared by vacuum cathodic arc deposition technology. The combustion chamber substrate material is niobium alloy, and the coating material is molybdenum or iridium. The inner hole diameter of the engine combustion chamber is 4 to 100 mm, the outer diameter is 4 to 110 mm, and the combustion chamber length is 5 to 300 mm. The coating thickness does not exceed 300 μm.

2. A cooling device applicable to the cooling method of the arc ion plating equipment according to claim 1, characterized in that: It includes a protective gas channel, a workpiece real-time temperature monitoring device, a flow control device for the protective gas, and an adjustable-speed fan; A protective gas channel is arranged above the coating preparation furnace and is connected to a gas cylinder through a flow control device for the protective gas; The engine combustion chamber is placed on the workbench inside the coating preparation furnace. The workpiece real-time temperature monitoring device is installed through the coating preparation furnace and is used to detect the surface temperature of the engine combustion chamber during the cooling process. The adjustable-speed stage fan is placed inside the coating preparation furnace and, together with the flow control device of the protective gas, maintains the air pressure inside the furnace within the range of 1×10 0 to 1×10 -3 during the cooling process.

3. The cooling device according to claim 2, characterized in that: The workpiece real-time temperature monitoring device includes a thermocouple installed on the structural member and a transmission and control mechanism equipped with an isolation baffle. The position of the thermocouple faces the straight section of the engine combustion chamber; During the coating preparation process of the workpiece, the isolation baffle isolates the thermocouple. During the cooling process of the workpiece, the isolation baffle is withdrawn, and the thermocouple works normally, effectively protecting the device from being affected by the coating.

4. The cooling device according to claim 3, characterized in that: The position of the thermocouple is such that after the engine combustion chamber is inverted up and down, it faces the position between the lower part of the nozzle outlet and the throat; 5. The cooling device according to claim 2, characterized in that: The flow control device for the protective gas includes a gas input and output device, a gas flow controller, a gas channel isolation plate, and a control system. The gas input and output device is used to supply the protective gas to the protective gas channel and to recover the gas in the coating preparation furnace. The gas flow controller controls the gas flow in the protective gas channel. The gas channel isolation plate is used to cut off the protective gas channel and the coating preparation furnace during coating preparation and to open the protective gas channel during cooling. The control system is used to control the gas input and output device, the gas flow controller, and the gas channel isolation plate.

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