Tubular inner wall double glow plasma processing apparatus and method

Abstract

The application discloses a tubular object inner wall double-glow plasma processing device, which comprises an electrode rod and a bottom disc; the bottom disc is connected with a target material tray through a first ceramic support, and the bottom disc is connected with a workpiece tray through a second ceramic support; the target material tray is provided with a target material one and a target material two, and the target material one and the target material two are in a disc shape; a hole with the same inner diameter as the workpiece is reserved on the workpiece tray, and a hollow heat preservation cover is further arranged on the workpiece tray; the workpiece is arranged at the middle position of the target material one and the target material two, and the center lines of the target material one, the target material two, the workpiece and the hollow heat preservation cover are coincident; the target material tray is connected with an electrode rod one, and the workpiece tray is connected with an electrode rod two. The application further discloses a processing method of the tubular object inner wall double-glow plasma processing device. The outer walls of the two metal target materials and the inner wall of the tubular object are at equal intervals and are located on the upper and lower sides of the tubular object, the film layer is uniform and dense, no hole and crack appear, the film layer is combined with the base body in a metallurgical way, and the service life is improved.

Description

Technical Field

[0001] This invention pertains to dual-glow plasma treatment devices and methods, specifically a dual-glow plasma treatment device and method for the inner wall of a tubular object. Background Technology

[0002] Artillery is the main equipment for land-based firepower and an important component of the firepower systems of other branches of the armed forces. It is one of the most numerous and widely used weapons in the army, navy, and air force. Tubular artillery operates under harsh conditions, including high temperatures, high pressures, ablation, and frictional thermal shocks, which significantly impacts its service life. This severely restricts the realization of high-strength firepower and the improvement of service life, and can even lead to major safety hazards. The service life of tubular artillery in my country is only half that of international advanced levels, making it a critical issue that urgently needs to be addressed in the development of next-generation equipment.

[0003] Dual-glow plasma surface metallurgy technology offers advantages such as rapid alloying speed, a wide range of alloying element selection, and no hydrogen embrittlement. It is well-suited for anti-ablation and wear treatment of the inner walls of artillery tubular structures, and also boasts advantages such as minimal impact on workpiece dimensional accuracy and zero pollution during the process. By adjusting process parameters, the thickness, microstructure, and properties of the surface coating can be controlled, thereby extending the lifespan of the tubular structures.

[0004] To achieve the desired results, the tooling structure for dual-glow plasma surface metallurgical treatment is particularly crucial. In existing dual-glow devices, the target material is often placed on one side of the workpiece, resulting in uneven and dense film thickness, and the appearance of pores and cracks. Summary of the Invention

[0005] Purpose of the invention: In order to overcome the shortcomings of the prior art, the purpose of this invention is to provide a dual-glow plasma treatment device for the inner wall of tubular objects that is suitable for tubular objects and has a uniform coating quality. Another purpose of this invention is to provide a low-cost, simple and convenient method for dual-glow plasma treatment of the inner wall of tubular objects of various sizes.

[0006] Technical Solution: The present invention provides a dual-glow plasma treatment device for the inner wall of a tubular object, comprising an electrode rod and a base. The base is connected to a target tray via a first ceramic support, and to a workpiece tray via a second ceramic support. The target tray is provided with a first target and a second target, both of which are disc-shaped. The workpiece tray has a hole with a diameter equal to that of the workpiece, and a hollow heat-insulating cover is also provided on the workpiece tray. The workpiece is positioned between the first and second targets, with the center lines of the first target, the second target, the workpiece, and the hollow heat-insulating cover coinciding. The target tray is connected to the first electrode rod, and the workpiece tray is connected to the second electrode rod. Further, the first and second ceramic supports are both aluminosilicate tubes, used to fix the positions of the workpiece tray, the target tray, and the first and second targets, ensuring a suitable discharge distance between the two electrodes of the fixture structure.

[0007] Furthermore, the target material tray includes an upper layer and a lower layer, with grooves reserved in the lower and upper layers for placing target material one and target material two, respectively; the grooves in the upper layer are hollow and stepped, and the minimum diameter of the grooves in the upper layer is the same as the inner diameter of the workpiece; the diameter of the grooves in the lower layer is the same as the inner diameter of the workpiece.

[0008] Furthermore, the diameter of target material one is 0-5 mm smaller than the inner diameter of the groove in the lower layer of the target material tray, and the diameter of target material two is 0-5 mm smaller than the inner diameter of the groove in the upper layer of the target material tray. Target material one and target material two are made of Ta-10W alloy with a surface roughness of Ra0.8, which greatly improves the wear resistance, thermal shock resistance and ablation resistance of the inner wall of the tubular object.

[0009] Furthermore, the distances between target material one, target material two and the workpiece are the same, both being 15-20mm.

[0010] Furthermore, the distance between the target material tray and the chassis is 60-70mm.

[0011] Furthermore, the target tray, workpiece tray, and hollow insulation cover are all made of 304 stainless steel with a surface roughness of Ra0.8, exhibiting strong oxidation resistance and durability. The hollow insulation cover serves to maintain heat during the processing and also features an observation window at the front for observing the glow phenomenon of the target material and tubular workpiece.

[0012] The treatment method of the above-mentioned tubular inner wall dual-glow plasma treatment device includes the following steps:

[0013] (a) Perform surface pretreatment on each assembly component, including grinding, polishing, cleaning, and wiping, before loading it into the furnace;

[0014] (b) Evacuate the furnace environment to a low vacuum state;

[0015] (c) Adjust the inlet flow rate to 100–110 sccm to balance the inlet and outlet flow rates within the furnace, maintaining a stable gas pressure of 36–42 Pa during the test. Turn on the source and workpiece electrode voltage adjustment switches on the double-glow furnace. The source electrode voltage is the voltage between electrode rod one and the ground, and the workpiece electrode voltage is the voltage between electrode rod two and the ground. Gradually increase the source electrode voltage to 700–850 V and the workpiece electrode voltage to 420–480 V, with a frequency range of 40.0–41.0 Hz, ensuring the two currents reach 1.3 A and 2.3 A respectively. Maintain the temperature for 2–3.5 hours. Gradually decrease the source and workpiece electrode voltages to 300 V, then turn off the power switches and evacuate the furnace to 10°C. -1 Pa, and finally turn off each power switch in turn;

[0016] (d) After annealing at 590-610℃ for 3-4 hours, the tube is cooled to 400℃ in the furnace and then removed from the furnace and cooled in the air. This is beneficial for efficiently and maximally eliminating residual stress, while avoiding new adverse effects on the tubular material and further improving the mechanical properties of the tubular material.

[0017] Further, in step (a), grinding involves using a small grinder to grind the surface of each assembly component to remove dust splashed onto the surface; polishing involves using metallographic sandpaper to grind from coarse to fine, up to 2000 grit, and then mechanically polishing the surface of each assembly component; cleaning involves placing each assembly component in a container filled with acetone or alcohol for ultrasonic cleaning, and then placing it in a plasma cleaner for further cleaning through argon plasma etching; wiping involves using a clean gauze.

[0018] Furthermore, the process parameters of the plasma cleaner are as follows: chamber wall voltage 420–450V, magnetic induction intensity generated by the permanent magnet 160–180Gs, gas pressure 0.5–0.6Pa, and radio frequency power density 3.8–4.5W / cm². 2 Cleaning temperature 300~350℃, cleaning time 1~2 hours.

[0019] Furthermore, step (b) specifically includes the following steps:

[0020] (b1) Turn on the cooling water circulation device connected to the double glow furnace. The water circulates outside the double glow furnace. Turn on the power to the double glow furnace. After closing the vent valve, start the mechanical pump to pump the furnace environment to 10°C. -1 Below Pa;

[0021] (b2) Open the intake valve switch and adjust the intake flow rate to 30-60 sccm. At this time, the air pressure reading will increase. Evacuate the air pressure in the intake pipe to 10. -1 Below Pa;

[0022] (b3) Open the argon cylinder valve, adjust the inlet flow rate to the maximum reading, turn off the mechanical pump, introduce argon into the furnace to 190-200 Pa, then adjust the inlet flow rate to zero, turn on the mechanical pump, and evacuate again to 10 Pa. -1 If the pressure is below 100 Pa, repeat this step 2-3 times.

[0023] Working Principle: This invention utilizes the double-layer glow discharge phenomenon to generate argon ions within a double-glow furnace. A potential difference exists between the source and workpiece electrodes. The accelerated argon ions bombard a metal target, sputtering out elements that deposit and diffuse to form an alloy layer on the inner surface of the tubular object. Simultaneously, the tubular object is heated to a high temperature, allowing metal elements to diffuse into the interior, forming a diffusion layer and increasing penetration depth and amount. The bonding strength between the tubular substrate and the alloy layer is significantly improved through metallurgical bonding. The dual-target design enhances the bombardment efficiency within the tubular object while also limiting element diffusion direction to some extent, thus improving target utilization.

[0024] A small amount of pure argon gas is introduced into the plasma cleaner chamber. With the target material grounded and maintaining zero potential, a positive voltage is applied to the chamber wall. The magnetic field generated by the permanent magnet surrounding the target's central axis, combined with the applied radial electric field, forms an argon plasma ring. During cleaning, the argon plasma bombards the surface of the object being cleaned, achieving an atomic-level cleaning effect. The etched impurities and contaminants are collected inside the plasma cleaner. Plasma cleaning can remove a large amount of impurities and contaminants from the surface of components, achieving an atomic-level cleaning effect. It avoids the "excessive flickering" phenomenon during the discharge process, reduces the residual stress generated by impurity elements in the alloy layer structure, and helps achieve the desired effect of stress-relief annealing.

[0025] Beneficial effects: Compared with the prior art, the present invention has the following significant features:

[0026] 1. Target material one and target material two are spaced equally with the tubular object, resulting in a film layer with uniform and dense thickness, without pores or cracks.

[0027] 2. The film prepared by the dual-glow plasma metallurgy technology consists of a deposition layer and a diffusion layer, which are metallurgically bonded to the substrate. It has excellent performance and can significantly improve the wear resistance, thermal shock resistance and ablation resistance of the inner wall of the tubular object, thereby increasing the service life of the gun barrel in practical applications.

[0028] 3. The method for preparing the tantalum-tungsten coating on the inner wall of the tubular object of the present invention has low cost, relatively simple process equipment, and is easy to achieve mass production. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of the present invention. Detailed Implementation

[0030] like Figure 1The base 2 of the dual-glow plasma treatment device on the inner wall of the tubular structure is fixedly connected to the target tray 4 via the first ceramic support 3, and the base 2 is fixedly connected to the workpiece tray 8 via the second ceramic support 7. Two disc-shaped metal targets, target 5 and target 6, are mounted on the target tray 4. A hole with the same inner diameter as the workpiece 9 is pre-drilled on the workpiece tray 8, and a hollow insulation cover 10 is also mounted on the workpiece tray 8. The workpiece 9 is positioned between target 5 and target 6, and the center lines of target 5, target 6, workpiece 9, and hollow insulation cover 10 coincide. The target tray 4 is tightly connected to electrode rod 11 via bolts and nuts, and the workpiece tray 8 is tightly connected to electrode rod 11 via bolts and nuts. Both the first ceramic support 3 and the second ceramic support 7 are aluminosilicate tubes. The target tray 4 has a double-layer structure. The lower and upper layers are respectively designed with grooves for placing target material 5 and target material 6. The upper groove is a hollow stepped shape with a central platform width of 3-5mm and a lower hollow diameter that matches the inner diameter of workpiece 9. The lower groove has the same diameter as the inner diameter of workpiece 9. The diameter of target material 5 is slightly smaller than the diameter of the lower groove of target tray 4, and the diameter of target material 6 is slightly smaller than the diameter of the upper hollow section of the upper groove of target tray 4. Target material 5 and target material 6 are equidistant from workpiece 9, both being 15-20mm. The metal targets are made of Ta-10W alloy, with dimensions customized according to workpiece 9, and a surface roughness of Ra0.8. The distance between the lower layer of target tray 4 and the base plate 2 is 60-70mm. Target tray 4, workpiece tray 8, and hollow insulation cover 10 are all made of 304 stainless steel with a surface roughness of Ra0.8, exhibiting strong oxidation resistance and durability. The hollow heat insulation cover 10 plays a role in heat preservation during the process, and at the same time, it has an observation window at the front to observe the glow phenomenon of the target material 5, the target material 6 and the tubular workpiece 9.

[0031] The dual-glow plasma treatment device also includes source electrode and workpiece electrode voltage adjustment switches, various power switches, cooling circulating water device, mechanical pump, etc., which have been disclosed in the paper "γ-TiAl dual-glow plasma W-Mo co-diffusion process and performance study of modified layer".

[0032] Example 1

[0033] A method for treating the inner wall of a tubular object using a dual-glow plasma treatment device includes the following steps:

[0034] a. Perform surface pretreatment on each assembly component, including grinding, polishing, cleaning, and wiping, before loading it into the furnace;

[0035] (a1) Grinding: Use a small grinder to grind the surface of each assembled part to remove dust and other dirt that has splashed onto the surface.

[0036] (a2) Polishing: Use metallographic sandpaper to grind from coarse to fine, up to 2000 grit, and then mechanically polish the surfaces of each assembled component.

[0037] (a3) Cleaning: Each assembled component is placed in a container filled with acetone or alcohol for ultrasonic cleaning, and then placed in a plasma cleaner for further cleaning by argon plasma etching. The process parameters of the plasma cleaner are: chamber wall voltage 420V, magnetic induction intensity generated by the permanent magnet 160Gs, gas pressure 0.5Pa, and radio frequency power density 3.8W / cm². 2 Cleaning temperature 300℃, cleaning time 1 hour.

[0038] (a4) Wiping: Wipe the furnace body and the surface of each assembly component with a clean gauze to ensure that the test device and the surface of each component are dry and clean, and then complete the assembly according to the tooling structure.

[0039] b. Evacuate the furnace environment to a low vacuum state:

[0040] (b1) Turn on the cooling water circulation device connected to the double glow furnace. The water circulates outside the double glow furnace. Turn on the power to the double glow furnace. After closing the vent valve, start the mechanical pump to pump the furnace environment to 10°C. -1 Below Pa.

[0041] (b2) Open the intake valve switch and adjust the intake flow rate to 30 sccm. At this time, the air pressure reading will increase. Evacuate the air pressure in the intake pipe to 10 sccm. -1 Below Pa.

[0042] (b3) Open the argon cylinder valve, adjust the inlet flow rate to the maximum reading, turn off the mechanical pump, introduce argon into the furnace to 200 Pa, then adjust the inlet flow rate to zero, turn on the mechanical pump, and evacuate again to 10 Pa. -1 If the pressure is below 100 Pa, repeat this step twice.

[0043] c. An alloy layer is prepared on the inner wall of the tubular workpiece 9 using a double-layer glow discharge plasma surface metallurgy method:

[0044] (c1) Adjust the air inlet flow rate to 100 sccm, and adjust the mechanical valve knob to keep the air inlet and exhaust flow in the furnace in balance. The air pressure is stable at 36 Pa during the test.

[0045] (c2) Turn on the source electrode and workpiece electrode voltage adjustment switch on the double glow test furnace. The source electrode voltage is the voltage between electrode rod one and the ground, and the workpiece electrode voltage is the voltage between electrode rod two and the ground. Gradually increase the source electrode voltage to 700V and the workpiece electrode voltage to 420V, with a frequency range of 40.0Hz, so that the current of the two stages reaches 1.3A and 2.3A respectively. After the voltage increase is completed, keep it at the temperature for 2 hours. Then gradually adjust the duty cycle of the two stages to keep the current of the two stages near the above values.

[0046] (c3) Gradually reduce the source and workpiece electrode voltages to 300V, then turn off the power switch for both electrodes and evacuate the furnace gas to 10V.-1 Pa, and finally turn off each power switch in turn.

[0047] d. After annealing at 600℃ for 3 hours, remove from the furnace and allow to cool in air after the furnace has cooled to 400℃.

[0048] A Ta-W alloy layer with a thickness of 14 μm was formed on the inner wall of the tubular workpiece 9.

[0049] Example 2

[0050] A method for treating the inner wall of a tubular object using a dual-glow plasma treatment device includes the following steps:

[0051] a. Perform surface pretreatment on each assembly component, including grinding, polishing, cleaning, and wiping, before loading it into the furnace;

[0052] (a1) Grinding: Use a small grinder to grind the surface of each assembled part to remove dust and other dirt that has splashed onto the surface.

[0053] (a2) Polishing: Use metallographic sandpaper to grind from coarse to fine, up to 2000 grit, and then mechanically polish the surfaces of each assembled component.

[0054] (a3) Cleaning: Each assembled component is placed in a container filled with acetone or alcohol for ultrasonic cleaning, and then placed in a plasma cleaner for further cleaning via argon plasma etching. The process parameters of the plasma cleaner are: chamber wall voltage 450V, magnetic induction intensity generated by the permanent magnet 180Gs, gas pressure 0.6Pa, and radio frequency power density 4.5W / cm². 2 Cleaning temperature 350℃, cleaning time 2 hours.

[0055] (a4) Wiping: Wipe the furnace body and the surface of each assembly component with a clean gauze to ensure that the test device and the surface of each component are dry and clean, and then complete the assembly according to the tooling structure.

[0056] b. Evacuate the furnace environment to a low vacuum state:

[0057] (b1) Turn on the cooling water circulation device connected to the double glow furnace. The water circulates outside the double glow furnace. Turn on the power to the double glow furnace. After closing the vent valve, start the mechanical pump to pump the furnace environment to 10°C. -1 Below Pa.

[0058] (b2) Open the intake valve switch and adjust the intake flow rate to 60 sccm. At this time, the air pressure reading will increase. Evacuate the air pressure in the intake pipe to 10 sccm. -1 Below Pa.

[0059] (b3) Open the argon cylinder valve, adjust the inlet flow rate to the maximum reading, turn off the mechanical pump, introduce argon into the furnace to 200 Pa, then adjust the inlet flow rate to zero, turn on the mechanical pump, and evacuate again to 10 Pa. -1 If the pressure is below 100 Pa, repeat this step twice.

[0060] c. An alloy layer is prepared on the inner wall of the tubular workpiece 9 using a double-layer glow discharge plasma surface metallurgy method:

[0061] (c1) Adjust the air inlet flow rate to 100 sccm, and adjust the mechanical valve knob to keep the air inlet and exhaust flow in the furnace in balance. The air pressure is stable at 38 Pa during the test.

[0062] (c2) Turn on the source electrode and workpiece electrode voltage adjustment switch on the double glow test furnace. The source electrode voltage is the voltage between electrode rod one and the ground, and the workpiece electrode voltage is the voltage between electrode rod two and the ground. Gradually increase the source electrode voltage to 750V and the workpiece electrode voltage to 440V, with a frequency range of 41.0Hz, so that the current of the two stages reaches 1.3A and 2.3A respectively. After the voltage increase is completed, keep it at the temperature for 2.5h. That is, gradually adjust the duty cycle of the two stages to keep the current of the two stages near the above values.

[0063] (c3) Gradually reduce the source and workpiece electrode voltages to 300V, then turn off the power switch for both electrodes and evacuate the furnace gas to 10V. -1 Pa, and finally turn off each power switch in turn.

[0064] d. After annealing at 600℃ for 3.5 hours, the furnace is cooled to 400℃ and then removed from the furnace and cooled in air.

[0065] The inner wall of the tubular workpiece 9 is formed with a Ta-W alloy layer with a thickness of 18 μm.

[0066] Example 3

[0067] A method for treating the inner wall of a tubular object using a dual-glow plasma treatment device includes the following steps:

[0068] a. Perform surface pretreatment on each assembly component, including grinding, polishing, cleaning, and wiping, before loading it into the furnace;

[0069] (a1) Grinding: Use a small grinder to grind the surface of each assembled part to remove dust and other dirt that has splashed onto the surface.

[0070] (a2) Polishing: Use metallographic sandpaper to grind from coarse to fine, up to 2000 grit, and then mechanically polish the surfaces of each assembled component.

[0071] (a3) Cleaning: Each assembled component is placed in a container filled with acetone or alcohol for ultrasonic cleaning, and then placed in a plasma cleaner for further cleaning via argon plasma etching. The process parameters of the plasma cleaner are: chamber wall voltage 430V, magnetic induction intensity generated by the permanent magnet 170Gs, gas pressure 0.5Pa, and radio frequency power density 4.2W / cm². 2 Cleaning temperature 320℃, cleaning time 1.5h.

[0072] (a4) Wiping: Wipe the furnace body and the surface of each assembly component with a clean gauze to ensure that the test device and the surface of each component are dry and clean, and then complete the assembly according to the tooling structure.

[0073] b. Evacuate the furnace environment to a low vacuum state:

[0074] (b1) Turn on the cooling water circulation device connected to the double glow furnace. The water circulates outside the double glow furnace. Turn on the power to the double glow furnace. After closing the vent valve, start the mechanical pump to pump the furnace environment to 10°C. -1 Below Pa.

[0075] (b2) Open the intake valve switch and adjust the intake flow rate to 45 sccm. At this time, the air pressure reading will increase. Evacuate the air pressure in the intake pipe to 10. -1 Below Pa.

[0076] (b3) Open the argon cylinder valve, adjust the inlet flow rate to the maximum reading, turn off the mechanical pump, introduce argon into the furnace to 195 Pa, then adjust the inlet flow rate to zero, turn on the mechanical pump, and evacuate again to 10 Pa. -1 If the pressure is below 100 Pa, repeat this step twice.

[0077] c. An alloy layer is prepared on the inner wall of the tubular workpiece 9 using a double-layer glow discharge plasma surface metallurgy method:

[0078] (c1) Adjust the air inlet flow rate to 105 sccm, and adjust the mechanical valve knob to keep the air inlet and exhaust flow in the furnace in balance. The air pressure is stable at 40 Pa during the test.

[0079] (c2) Turn on the source electrode and workpiece electrode voltage adjustment switch on the double glow test furnace. The source electrode voltage is the voltage between electrode rod one and the ground, and the workpiece electrode voltage is the voltage between electrode rod two and the ground. Gradually increase the source electrode voltage to 800V and the workpiece electrode voltage to 460V, with a frequency range of 40.0Hz, so that the current of the two stages reaches 1.3A and 2.3A respectively. After the voltage increase is completed, keep it at the temperature for 3 hours. That is, gradually adjust the duty cycle of the two stages to keep the current of the two stages near the above values.

[0080] (c3) Gradually reduce the source and workpiece electrode voltages to 300V, then turn off the power switch for both electrodes and evacuate the furnace gas to 10V.-1 Pa, and finally turn off each power switch in turn.

[0081] d. After annealing at 605℃ for 4 hours, remove from the furnace and cool to 400℃, then cool in air.

[0082] The inner wall of the tubular workpiece 9 is formed with a Ta-W alloy layer with a thickness of 17 μm.

[0083] Example 4

[0084] A method for treating the inner wall of a tubular object using a dual-glow plasma treatment device includes the following steps:

[0085] a. Perform surface pretreatment on each assembly component, including grinding, polishing, cleaning, and wiping, before loading it into the furnace;

[0086] (a1) Grinding: Use a small grinder to grind the surface of each assembled part to remove dust and other dirt that has splashed onto the surface.

[0087] (a2) Polishing: Use metallographic sandpaper to grind from coarse to fine, up to 2000 grit, and then mechanically polish the surfaces of each assembled component.

[0088] (a3) Cleaning: Each assembled component is placed in a container filled with acetone or alcohol for ultrasonic cleaning, and then placed in a plasma cleaner for further cleaning via argon plasma etching. The process parameters of the plasma cleaner are: chamber wall voltage 440V, magnetic induction intensity generated by the permanent magnet 175Gs, gas pressure 0.6Pa, and radio frequency power density 4.4W / cm². 2 Cleaning temperature 330℃, cleaning time 1 hour.

[0089] (a4) Wiping: Wipe the furnace body and the surface of each assembly component with a clean gauze to ensure that the test device and the surface of each component are dry and clean, and then complete the assembly according to the tooling structure.

[0090] b. Evacuate the furnace environment to a low vacuum state:

[0091] (b1) Turn on the cooling water circulation device connected to the double glow furnace. The water circulates outside the double glow furnace. Turn on the power to the double glow furnace. After closing the vent valve, start the mechanical pump to pump the furnace environment to 10°C. -1 Below Pa.

[0092] (b2) Open the intake valve switch and adjust the intake flow rate to 40 sccm. At this time, the air pressure reading will increase. Evacuate the air pressure in the intake pipe to 10 sccm. -1 Below Pa.

[0093] (b3) Open the argon cylinder valve, adjust the inlet flow rate to the maximum reading, turn off the mechanical pump, introduce argon into the furnace to 190 Pa, then adjust the inlet flow rate to zero, turn on the mechanical pump, and evacuate again to 10 Pa. -1 If the pressure is below 100 Pa, repeat this step 3 times.

[0094] c. An alloy layer is prepared on the inner wall of the tubular workpiece 9 using a double-layer glow discharge plasma surface metallurgy method:

[0095] (c1) Adjust the air inlet flow rate to 110 sccm, and adjust the mechanical valve knob to keep the air inlet and exhaust flow in the furnace in balance. The air pressure is stable at 42 Pa during the test.

[0096] (c2) Turn on the source electrode and workpiece electrode voltage adjustment switch on the double glow test furnace. The source electrode voltage is the voltage between electrode rod one and the ground, and the workpiece electrode voltage is the voltage between electrode rod two and the ground. Gradually increase the source electrode voltage to 850V and the workpiece electrode voltage to 480V, with a frequency range of 41.0Hz, so that the current of the two stages reaches 1.3A and 2.3A respectively. After the voltage increase is completed, keep it at the temperature for 3.5h. That is, gradually adjust the duty cycle of the two stages to keep the current of the two stages near the above values.

[0097] (c3) Gradually reduce the source and workpiece electrode voltages to 300V, then turn off the power switch for both electrodes and evacuate the furnace gas to 10V. -1 Pa, and finally turn off each power switch in turn.

[0098] d. After annealing at 610℃ for 3 hours, the furnace is cooled to 400℃ and then removed from the furnace and cooled in air.

[0099] A Ta-W alloy layer with a thickness of 15 μm is formed on the inner wall of the tubular workpiece 9.

Claims

1. A dual-glow plasma treatment device for the inner wall of a tubular object, characterized in that: It includes an electrode rod (1) and a base plate (2); the base plate (2) is connected to the target tray (4) through a first ceramic support (3), and the base plate (2) is connected to the workpiece tray (8) through a second ceramic support (7); the target tray (4) is provided with a target material (5) and a target material (6), and the target material (5) and the target material (6) are disc-shaped; the workpiece tray (8) has a hole with the same inner diameter as the workpiece (9), and the workpiece tray (8) is also provided with a hollow heat insulation cover (10); the workpiece (9) is provided in the middle position of the target material (5) and the target material (6), and the center lines of the target material (5), the target material (6), the workpiece (9), and the hollow heat insulation cover (10) coincide; the target tray (4) is connected to the electrode rod (1), and the workpiece tray (8) is connected to the electrode rod (11); The distances between the first target (5), the second target (6) and the workpiece (9) are the same, both being 15-20 mm; The target material tray (4) includes an upper layer and a lower layer. The lower layer and the upper layer are respectively reserved with grooves for placing target material one (5) and target material two (6). The groove of the upper layer is hollow and stepped. The minimum diameter of the groove of the upper layer is the same as the inner diameter of the workpiece (9). The diameter of the groove of the lower layer is the same as the inner diameter of the workpiece (9).

2. The dual-glow plasma treatment device for the inner wall of a tubular object according to claim 1, characterized in that: Both the first ceramic support (3) and the second ceramic support (7) are aluminum-silicon tubes.

3. The dual-glow plasma treatment device for the inner wall of a tubular object according to claim 1, characterized in that: The diameter of the first target (5) is 0-5 mm smaller than the inner diameter of the groove in the lower layer of the target tray (4), and the diameter of the second target (6) is 0-5 mm smaller than the inner diameter of the groove in the upper layer of the target tray (4).

4. The dual-glow plasma treatment device for the inner wall of a tubular object according to claim 1, characterized in that: The distance between the lower layer of the target material tray (4) and the base plate (2) is 60-70 mm.

5. The treatment method of the tubular inner wall dual-glow plasma treatment device according to any one of claims 1 to 4, characterized in that, Includes the following steps: (a) Perform surface pretreatment on each assembly component, including grinding, polishing, cleaning, and wiping, before loading it into the furnace; (b) Evacuate the furnace environment to a low vacuum state; (c) Adjust the inlet flow rate to 100~110 sccm to balance the inlet and outlet flow rates in the furnace. During the test, the gas pressure should be stable at 36~42 Pa. Turn on the source and workpiece electrode voltage adjustment switches on the double-glowing test furnace. The source electrode voltage is the voltage between electrode rod one (1) and the ground, and the workpiece electrode voltage is the voltage between electrode rod two (11) and the ground. Gradually increase the source electrode voltage to 700~850V and the workpiece electrode voltage to 420~480V, with a frequency range of 40.0~41.0Hz, so that the currents of the two electrodes reach 1.3A and 2.3A respectively. Keep warm for 2~3.5h. Gradually decrease the source and workpiece electrode voltages to 300V and then turn off the power switches of the two electrodes. Evacuate the gas in the furnace to 10 -1 Pa, and finally turn off each power switch in turn; (d) Hold at annealing temperature of 590~610℃ for 3~4 hours, cool with furnace to 400℃ and then remove from furnace and cool in air.

6. The processing method according to claim 5, characterized in that: In step (a), grinding involves using a small grinder to grind the surface of each assembly component to remove dust splashed on the surface; polishing involves using metallographic sandpaper to grind from coarse to fine, up to 2000 grit, and then mechanically polishing the surface of each assembly component; cleaning involves placing each assembly component in a container filled with acetone or alcohol for ultrasonic cleaning, and then placing it in a plasma cleaner for further cleaning through argon plasma etching; wiping involves using a clean gauze.

7. The processing method according to claim 6, characterized in that: The process parameters of the plasma cleaner are as follows: chamber wall voltage 420~450V, magnetic induction intensity generated by the permanent magnet 160~180Gs, air pressure 0.5~0.6Pa, and radio frequency power density 3.8~4.5W / cm². 2 Cleaning temperature 300~350℃, cleaning time 1~2 hours.

8. The processing method according to claim 7, characterized in that: Step (b) specifically includes the following steps: (b1) Turn on the cooling water circulation device connected to the double glow furnace. The water circulates outside the double glow furnace. Turn on the power to the double glow furnace. After closing the vent valve, start the mechanical pump to pump the furnace environment to 10°C. -1 Below Pa; (b2) Open the intake valve switch and adjust the intake flow rate to 30~60 sccm. At this time, the air pressure reading will increase. Evacuate the air pressure in the intake pipe to 10 sccm. -1 Below Pa; (b3) Open the argon cylinder valve, adjust the inlet flow rate to the maximum reading, turn off the mechanical pump, introduce argon into the furnace to 190~200 Pa, then adjust the inlet flow rate to zero, turn on the mechanical pump, and evacuate again to 10 Pa. -1 For levels below Pa, repeat this step 2-3 times.

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