Low-temperature dry-method CrN / AlO nano laminated vacuum coating process and equipment

Abstract

The invention discloses a low-temperature dry-method CrN / AlO plating nano laminated vacuum coating process and equipment, and relates to the technical field of vacuum coating, the low-temperature dry-method CrN / AlO plating nano laminated vacuum coating equipment comprises a shell and a gas injection assembly, an inner layer ring is fixed in the shell, a placement frame is fixed in the inner layer ring, and a gas injection assembly is fixed in the placement frame; a second temperature sensor and a pressure sensor are installed at the rear end of the interior of the shell, a water tank is fixed to the lower side of the shell, a water pump is installed in the water tank, and the low-temperature dry-method CrN / AlO nano laminated vacuum coating process comprises the following steps that S1, base material pretreatment is conducted, specifically, a base material to be coated is subjected to ultrasonic cleaning to remove surface pollutants, and the surface of the base material to be coated is subjected to vacuum drying; drying and then fixing on a placing rack; s2, constructing a vacuum environment: closing a sealing cover, starting a lock head, and vacuumizing an inner cavity of the shell by a vacuumizing pump until the vacuum degree is less than or equal to 5 * 10Pa; and the requirements of low-temperature treatment, nanoscale structure control and large-scale production can be met.

Description

Technical Field

[0001] The present invention relates to the field of vacuum coating technology, in particular to a low-temperature dry-coating CrN / Al2O3 nano-laminated vacuum coating process and equipment. Background Art

[0002] In the field of tool coating and precision component surface treatment, physical vapor deposition (PVD) and chemical vapor deposition (CVD) are the mainstream coating technologies. Traditional PVD processes such as magnetron sputtering need to be carried out at high temperatures above 400°C, which causes thermal deformation of low-melting-point substrates such as aluminum alloys and engineering plastics. For example, after the 7075 aluminum alloy for aviation is treated at 300°C for 2 hours, the surface microhardness drops by about 20%, which seriously restricts its application in precision components. Although CVD technology can generate a dense aluminum oxide film layer, it relies on toxic gases such as titanium tetrachloride (TiCl4). The cost of process waste gas treatment accounts for 15%-20% of the total production cost, and the residual chloride ions in the reaction will cause substrate corrosion. Neither of these two types of technologies can take into account the dual needs of low-temperature processing and high-performance coatings; In recent years, the industry has attempted to improve coating performance by modifying equipment structure, but significant drawbacks remain. Composite coating technologies (such as alternating CrN / TiN deposition) require preheating the substrate to above 380°C to achieve interlayer bonding, leading to stress accumulation within the film and resulting in a bonding force of less than 30N in scratch tests. While the plasma-enhanced CVD process reduces the temperature to below 300°C, the film contains high impurities and exhibits a 40% decrease in wear resistance compared to traditional processes. High-power pulsed magnetron sputtering (HiPIMS) technology can improve film-substrate bonding, but equipment energy consumption is 2-3 times that of conventional magnetron sputtering, and target utilization is less than 50%, making it difficult to meet the demands of large-scale production. The current market is placing higher demands on coating technology: precision medical devices require the preparation of biotoxic nano-laminated films below 200°C; new energy vehicle battery housings require coatings with both high hardness (≥30GPa) and resistance to electrolyte corrosion; and flexible electronic device substrates require uniform coating on complex curved surfaces. However, existing technologies are limited by high-temperature processes, single-layer film structures, and poor equipment compatibility. They are unable to simultaneously meet the requirements of low-temperature processing, nanoscale structure control, and large-scale production, becoming a bottleneck restricting the manufacture of high-end equipment. To address this, we propose a low-temperature dry-process CrN / Al2O3 nano-layer vacuum coating process and equipment. Summary of the Invention

[0003] In response to the shortcomings of the existing technology, the present invention provides a low-temperature dry-plating CrN / Al2O3 nano-laminated vacuum coating process and equipment, which can meet the needs of low-temperature processing, nano-scale structure control and large-scale production, and can effectively solve the problems in the background technology.

[0004] To achieve the above-mentioned object, the present invention provides the following technical solution: a low-temperature dry-process CrN / Al2O3 nano-layer vacuum coating device, comprising a housing and a gas injection component: Outer shell: an inner ring is fixed inside, a placement rack is fixed inside the inner ring, a second temperature sensor and a pressure sensor are installed at the rear end of the inner shell, a water tank is fixed on the lower side of the outer shell, a water pump is installed inside the water tank, a bracket is fixed on the lower side of the outer shell, a PLC controller is installed on the right side of the outer shell, a cooling assembly is installed in the interlayer between the outer shell and the inner ring, the cooling assembly is connected to the water tank, a vacuum assembly and a pressure relief assembly are installed at the rear end of the outer shell, two symmetrical injection assemblies are installed on the left and right ends of the upper end of the inner shell, a sealing assembly is installed at the front end of the outer shell, a refrigeration assembly is installed on the side of the water tank, and the refrigeration assembly cooperates with the cooling assembly; The air injection assembly comprises an air intake barrel, a flow meter, an air guide pipe, a first solenoid valve, an air intake pipe and a second solenoid valve; the rear end of the shell is provided with an air injection hole, an air intake pipe is fixed inside the air injection hole, and the second solenoid valve is installed on the circumferential surface of the air intake pipe; the rear end of the shell is fixed with an air intake barrel, the rear end of the air intake pipe is located inside the air intake barrel, a mounting hole is provided at the lower end of the circumferential surface of the air intake barrel, a flow meter is installed inside the mounting hole, three corresponding air guide holes are provided at the rear end of the air intake barrel, an air guide pipe is fixed inside the air guide hole, and the first solenoid valve is installed on the circumferential surface of the air guide pipe; Wherein: the input end of the PLC controller is electrically connected to the output end of the external power supply, the output end of the PLC controller is electrically connected to the input ends of the water pump, the first solenoid valve and the second solenoid valve respectively, and the PLC controller is bidirectionally electrically connected to the flow meter, the second temperature sensor and the pressure sensor respectively.

[0005] Preferably, the vacuum pump assembly includes a vacuum pump, an exhaust pipe and a third solenoid valve. The vacuum pump is installed at the rear end of the shell. The exhaust pipe is fixed inside the exhaust hole of the vacuum pump. The third solenoid valve is installed on the circumferential surface of the exhaust pipe. The upper end of the exhaust pipe is fixed inside the exhaust hole set at the rear end of the shell. The input ends of the third solenoid valve and the vacuum pump are electrically connected to the output end of the PLC controller.

[0006] Preferably, the injection assembly includes a target material inlet pipe, a sputtering nozzle, an injection hose and a fourth solenoid valve. Two corresponding target material inlet holes are opened at the upper end of the rear end of the shell. The target material inlet hole is fixed inside the target material inlet pipe. The lower end of the circumferential surface of the target material inlet pipe is equipped with evenly distributed sputtering nozzles. The rear end of the target material inlet pipe is fixed with an injection hose. The circumferential surface of the injection hose is equipped with a fourth solenoid valve. The input end of the fourth solenoid valve is electrically connected to the output end of the PLC controller.

[0007] Preferably, the pressure relief assembly includes a pressure relief pipe and a pressure relief valve, a pressure relief hole is provided at the rear end of the shell, a pressure relief pipe is fixed inside the pressure relief hole, a pressure relief valve is installed on the circumferential surface of the pressure relief pipe, and the input end of the pressure relief valve is electrically connected to the output end of the PLC controller.

[0008] Preferably, the cooling assembly includes a spiral cooling pipe, a water inlet pipe and a water outlet pipe. The spiral cooling pipe is sleeved on the circumferential surface of the inner ring, the water inlet pipe is fixed inside the water inlet of the spiral cooling pipe, and the water outlet pipe is fixed inside the water outlet of the spiral cooling pipe. The water inlet pipe is connected to the water outlet of the water pump, and the water outlet pipe is connected to the reflux port arranged on the side of the water tank.

[0009] Preferably, the refrigeration assembly includes a semiconductor refrigeration plate, a connecting frame, a heat dissipation fan, a protective net and a first temperature sensor. A mounting groove is provided on the front side of the water tank, a semiconductor refrigeration plate is installed inside the mounting groove, the heat dissipation end of the semiconductor refrigeration plate is located outside the mounting groove, and the cooling end of the semiconductor refrigeration plate is located inside the mounting groove. A connecting frame is fixed on the front side of the water tank, two corresponding heat dissipation fans are installed inside the connecting frame, and both heat dissipation fans correspond to the semiconductor refrigeration plate. An opening is provided on the right side of the water tank, a first temperature sensor is installed inside the opening, the first temperature sensor is electrically connected to the PLC controller in both directions, and the input ends of the semiconductor refrigeration plate and the heat dissipation fan are electrically connected to the output end of the PLC controller.

[0010] Preferably, the sealing assembly includes a sealing cover, a sealing rubber ring and a lock head. The front end of the shell is hinged with a sealing cover, the rear end of the sealing cover is fixed with a sealing rubber ring, the left end of the front end of the sealing cover is installed with a lock head, and the lock head is connected to the front end of the shell.

[0011] The low-temperature dry-process CrN / Al2O3 nano-layer vacuum coating process comprises the following steps: S1 Substrate pretreatment: The substrate to be coated is ultrasonically cleaned to remove surface contaminants, and then fixed on a placement rack after drying; S2 vacuum environment construction: Close the sealing cover and start the lock, and use the vacuum pump to evacuate the inner cavity of the shell to a vacuum degree of ≤5×10⁻³Pa; Argon gas is introduced into the gas inlet barrel through the gas guide tube, and the gas flow rate is controlled by the flow meter to be 20-50 sccm, and the cavity pressure is adjusted to 0.3-0.6 Pa; S3 low temperature alternating deposition: CrN layer deposition Open the target material inlet pipe connected to the Cr target, deliver the Cr target material through the injection hose, and the fourth solenoid valve controls the sputtering nozzle to open; Adjust the volume ratio of the N2 and Ar mixed gas to 1:3-1:5, the sputtering power to 200-300W, the chamber temperature monitored by the second temperature sensor to be 150-250°C, and deposit a single layer of CrN with a thickness of 50-100nm; Al2O3 layer deposition Close the fourth solenoid valve of the Cr target, switch to the Al target material inlet pipe, introduce a mixed gas of O2 and Ar (volume ratio 1:2-1:4), sputtering power 150-250W, maintain the temperature at 150-250℃, and deposit a single layer of Al2O3 with a thickness of 20-50nm; Inter-layer control Repeat step S3 by programming the PLC controller to alternately deposit 10-20 layers of CrN / Al2O3 with a total film thickness of 1-2 μm; S4 post-processing: Turn off the sputtering power supply, accelerate cooling through the spiral cooling tube and semiconductor refrigeration plate, and after the second temperature sensor shows the temperature is ≤50℃, open the pressure relief valve to restore normal pressure and take out the coating substrate.

[0012] Preferably, in step S3, the thickness ratio of the CrN layer to the Al2O3 layer is (2-5):1, and during the deposition of each layer: The cooling water is driven by a water pump to flow through the spiral cooling tube at a flow rate of 3-5L / min; The semiconductor refrigeration chip sets the cooling temperature to 5-10℃, and the cooling fan forces the heat to dissipate; The cavity temperature fluctuation is controlled by the PLC controller within ±5℃.

[0013] Preferably, in step S3, the uniformity of the film layer is achieved through the following linkage control: The pressure sensor monitors the cavity pressure in real time and feeds back to the PLC controller to dynamically adjust the opening of the first and second solenoid valves. The gas flow error is ≤±0.1sccm. The second temperature sensor collects temperature data every 30 seconds, and the PLC controller adjusts the power of the semiconductor refrigeration chip and the flow rate of the water pump through the PID algorithm, with a response time of ≤3 seconds; Sputtering power fluctuation ≤±2%, film thickness deviation ≤±5% In summary, compared with the prior art, the present invention provides a low-temperature dry-process CrN / Al2O3 nano-laminated vacuum coating process and equipment, which has the following beneficial effects: 1. Breakthrough in low-temperature process compatibility By using a double-layer water cooling system (spiral cooling tube 61) and a semiconductor cooling plate (71) to coordinate temperature control, the deposition temperature is stably controlled at 150-250°C, overcoming the problem of thermal damage to the substrate caused by the traditional high-temperature PVD process, and enabling high-performance coating of heat-sensitive materials such as aluminum alloys and engineering plastics; The application range of the substrate is extended to materials with a melting point below 300°C (such as PEEK and magnesium alloys), avoiding problems such as deformation and grain coarsening caused by high temperatures.

[0014] 2. Nano-laminated structure performance optimization Adopting the CrN / Al2O3 alternating deposition process (layer thickness ratio 2:1-5:1), the nano-level interface coupling effect is used to achieve a synergistic improvement in the hardness and toughness of the film layer, significantly enhancing the crack growth resistance. The film layer bonding strength is improved, solving the peeling problem caused by stress concentration in traditional single-layer films. It is especially suitable for high impact load conditions (such as tool cutting and aerospace components).

[0015] 3. Equipment integration and precise process control The PLC controller (15) dynamically adjusts the gas flow (N2 / O2 / Ar), sputtering power and layer switching sequence, with a gas flow error of <±0.1sccm and a temperature fluctuation of ≤±5°C, ensuring that the film thickness uniformity deviation is ≤±5%; The modularly designed magnetron target group (Cr target and Al target are arranged symmetrically) supports rapid target replacement, adapts to multi-material coating needs, and increases equipment utilization by more than 30%.

[0016] 4. Environmental protection and energy consumption advantages Abandoning the toxic gases (such as TiCl4) in the traditional CVD process, adopting dry magnetron sputtering technology, the process exhaust has no harmful by-products and meets the green manufacturing standards; The low-temperature process reduces equipment energy consumption by more than 35% (compared to traditional high-temperature PVD), and increases target utilization to 65%-70%, reducing material waste.

[0017] 5. Enhanced adaptability to complex working conditions The nano-laminated structure gives the coating excellent high-temperature oxidation resistance (suitable for aircraft engine components) and corrosion resistance (adaptable to marine salt spray and chemical corrosion environments); By adjusting the layer thickness ratio of CrN and Al2O3 (such as 5:1 to enhance hardness, 2:1 to improve toughness), it can be customized to meet the performance requirements of different application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the front side structure of the low-temperature dry-process CrN / Al2O3 nano-layer vacuum coating equipment of the present invention; Figure 2 This is a schematic diagram of the structure of the gas injection component of the low-temperature dry-process CrN / Al2O3 nano-layer vacuum coating equipment of the present invention; Figure 3 This is a schematic diagram of the rear side structure of the low-temperature dry-process CrN / Al2O3 nano-layer vacuum coating equipment of the present invention; Figure 4 This is a schematic diagram of the cooling assembly structure of the present invention low-temperature dry plating CrN / Al2O3 nano-laminated vacuum coating equipment; Figure 5 This is a schematic diagram of the refrigeration component structure of the low-temperature dry-process CrN / Al2O3 nano-laminated vacuum coating equipment of the present invention; In the figure: 1 shell, 2 gas injection assembly, 21 air intake barrel, 22 flow meter, 23 air guide pipe, 24 first solenoid valve, 25 air intake pipe, 26 second solenoid valve, 3 vacuum assembly, 31 vacuum pump, 32 air extraction pipe, 33 third solenoid valve, 4 injection assembly, 41 target material feed pipe, 42 sputtering nozzle, 43 injection hose, 44 fourth solenoid valve, 5 pressure relief assembly, 51 pressure relief pipe, 52 pressure relief valve, 6 cooling assembly, 61 spiral cooling pipe, 62 water inlet pipe, 63 water outlet pipe, 7 refrigeration assembly, 71 semiconductor refrigeration plate, 72 connecting frame, 73 cooling fan, 74 protective net, 75 first temperature sensor, 8 sealing assembly, 81 sealing cover, 82 sealing rubber ring, 83 lock, 9 water tank, 10 water pump, 11 bracket, 12 inner ring, 13 second temperature sensor, 14 pressure sensor, 15 PLC controller, 16 placement rack. DETAILED DESCRIPTION

[0019] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0020] See also Figure 1 The present invention provides a low-temperature dry-process CrN / Al2O3 nano-layer vacuum coating device, comprising a housing 1 and a gas injection component 2: Shell 1: An inner ring 12 is fixed inside, a placement rack 16 is fixed inside the inner ring 12, a second temperature sensor 13 and a pressure sensor 14 are installed at the rear end of the shell 1, a water tank 9 is fixed on the lower side of the shell 1, a water pump 10 is installed inside the water tank 9, a bracket 11 is fixed on the lower side of the shell 1, a PLC controller 15 is installed on the right side of the shell 1, a cooling component 6 is installed in the interlayer between the shell 1 and the inner ring 12, and the cooling component 6 is connected to the water tank 9, a vacuum component 3 and a pressure relief component 5 are installed at the rear end of the shell 1, two symmetrical injection components 4 are installed on the left and right ends of the upper end of the shell 1, and the shell 1 A sealing component 8 is installed at the front end, and a refrigeration component 7 is installed on the side of the water tank 9. The refrigeration component 7 cooperates with the cooling component 6. The outer shell 1 adopts a double-layer 304 stainless steel structure, with an outer wall thickness of 8mm and an inner ring 12 wall thickness of 5mm. The interlayer is filled with a ceramic fiber insulation layer (thermal conductivity coefficient ≤0.03W / m·K) to ensure that the external temperature of the cavity is ≤40°C. The concentricity error between the outer shell 1 and the inner ring 12 is ≤0.1mm to avoid deviation in the coating thickness. The second temperature sensor 13 is a K-type thermocouple with a measurement accuracy of ±0.5°C. The pressure sensor 14 is a piezoelectric crystal type with a range of 0-10Pa and a resolution of 0.01Pa. Gas injection assembly 2 comprises an air inlet barrel 21, a flowmeter 22, an air guide tube 23, a first solenoid valve 24, an air inlet tube 25, and a second solenoid valve 26. The rear end of the housing 1 is provided with an air injection hole, within which the air inlet tube 25 is fixed. A second solenoid valve 26 is mounted on the circumference of the air inlet tube 25. The air inlet barrel 21 is fixed to the rear end of the housing 1. The rear end of the air inlet tube 25 is located within the interior of the air inlet barrel 21. A mounting hole is provided at the lower end of the circumference of the air inlet barrel 21, within which the flowmeter 22 is mounted. The rear end of the air inlet barrel 21 is provided with three corresponding air guide holes, within which the air guide tube 23 is fixed. The first solenoid valve 24 is mounted on the upper circumference of the air guide tube 23. The air inlet barrel 21 has a capacity of 5L and is internally equipped with a honeycomb deflector (2mm aperture) to ensure 99% gas mixing uniformity. The flowmeter 22 is a mass flowmeter (MFC) with a range of 0-100sccm and a repeatability of ±0.1%. The inner diameter of the gas guide tube 23 is 6 mm and the length is uniformly 1.2 m to reduce gas transmission lag; The input end of the PLC controller 15 is electrically connected to the output end of the external power supply, the output end of the PLC controller 15 is electrically connected to the input ends of the water pump 10, the first solenoid valve 24 and the second solenoid valve 26 respectively, and the PLC controller 15 is bidirectionally electrically connected to the flow meter 22, the second temperature sensor 13 and the pressure sensor 14 respectively; The vacuum pump assembly 3 includes a vacuum pump 31, an exhaust pipe 32 and a third solenoid valve 33. The vacuum pump 31 is installed at the rear end of the housing 1. The exhaust pipe 32 is fixed inside the exhaust hole of the vacuum pump 31. The third solenoid valve 33 is installed on the circumferential surface of the exhaust pipe 32. The upper end of the exhaust pipe 32 is fixed inside the exhaust hole set at the rear end of the housing 1. The input ends of the third solenoid valve 33 and the vacuum pump 31 are electrically connected to the output end of the PLC controller 15. The vacuum pump 31 is a series combination of a molecular pump and a vortex pump, and the ultimate vacuum degree is ≤5×10⁻ 4 The inner wall of the exhaust pipe 32 is electropolished (roughness Ra ≤ 0.4 μm). The third solenoid valve 33 is a bellows sealed valve with a leakage rate of ≤ 1×10⁻ 9 Pa·m³ / s; The injection assembly 4 includes a target material inlet pipe 41, a sputtering nozzle 42, an injection hose 43, and a fourth solenoid valve 44. Two corresponding target material inlet holes are provided at the upper end of the rear end of the housing 1. The target material inlet pipe 41 is fixed inside the target material inlet hole. The sputtering nozzles 42 are evenly distributed at the lower end of the circumferential surface of the target material inlet pipe 41. The injection hose 43 is fixed to the rear end of the target material inlet pipe 41. The fourth solenoid valve 44 is installed on the circumferential surface of the injection hose 43. The input end of the fourth solenoid valve 44 is electrically connected to the output end of the PLC controller 15. The target material inlet pipe 41 has an inner diameter of 50mm and a gap of 0.5-1mm with the target material. The magnetic field strength of the magnetron target is 200-300Gs. The sputtering nozzle 42 adopts a ring array design (12 nozzles, aperture Φ2mm±0.05mm), with a distribution angle of 15°, to ensure sputtering uniformity >95%. The pressure relief assembly 5 includes a pressure relief pipe 51 and a pressure relief valve 52. A pressure relief hole is provided at the rear end of the housing 1. The pressure relief pipe 51 is fixed inside the pressure relief hole. The pressure relief valve 52 is installed on the circumferential surface of the pressure relief pipe 51. The input end of the pressure relief valve 52 is electrically connected to the output end of the PLC controller 15. Cooling assembly 6 includes a spiral cooling tube 61, an inlet pipe 62, and an outlet pipe 63. Spiral cooling tube 61 is sleeved onto the circumference of inner ring 12. The inlet of spiral cooling tube 61 is fixed with inlet pipe 62, and the outlet of spiral cooling tube 61 is fixed with outlet pipe 63. Inlet pipe 62 is connected to the outlet of water pump 10, and outlet pipe 63 is connected to the reflux port on the side of water tank 9. Spiral cooling tube 61 is made of copper (purity ≥ 99.9%), with a pitch of 20mm and five turns. At a flow rate of 3L / min through inlet pipe 62, the heat exchange efficiency reaches 1200W / m²·K, reducing the cavity wall temperature from 250°C to below 80°C. The refrigeration assembly 7 includes a semiconductor refrigeration plate 71, a connecting frame 72, a heat dissipation fan 73, a protective net 74, and a first temperature sensor 75. A mounting slot is provided on the front side of the water tank 9, inside which the semiconductor refrigeration plate 71 is mounted. The heat dissipation end of the semiconductor refrigeration plate 71 is located outside the mounting slot, while the cooling end of the semiconductor refrigeration plate 71 is located inside the mounting slot. A connecting frame 72 is fixed to the front side of the water tank 9, inside which two corresponding heat dissipation fans 73 are mounted, each corresponding to the semiconductor refrigeration plate 71. An opening is provided on the right side of the water tank 9, inside which a first temperature sensor 75 is mounted. The first temperature sensor 75 is bidirectionally electrically connected to the PLC controller 15. The input ends of the semiconductor refrigeration plate 71 and the heat dissipation fan 73 are both electrically connected to the output end of the PLC controller 15. The semiconductor refrigeration plate 71 is model TEC1-12706, with a cooling power of 72W and a temperature difference of ≥65°C. The heat dissipation fan 73 has an air volume of 25CFM and a noise level of ≤45dB. The first temperature sensor 75 is a PT100 platinum resistor with an accuracy of ±0.2°C. The sealing assembly 8 includes a sealing cover 81, a sealing rubber ring 82 and a lock 83. The front end of the shell 1 is hinged with the sealing cover 81, the rear end of the sealing cover 81 is fixed with a sealing rubber ring 82, and the left end of the front end of the sealing cover 81 is installed with a lock 83, which is connected to the front end of the shell 1.

[0021] The low-temperature dry-process CrN / Al2O3 nano-layer vacuum coating process comprises the following steps: S1 substrate pretreatment: ultrasonically clean the substrate to be coated to remove surface contaminants, dry it, and then fix it on a placement rack 16; S2 Vacuum Environment Establishment: Close the sealing cover 81 and activate the lock 83. Use the vacuum pump 31 to evacuate the inner cavity of the housing 1 to a vacuum level of ≤5×10⁻³Pa. Argon gas is introduced into the gas inlet barrel 21 through the gas guide tube 23. The gas flow rate is controlled by the flowmeter 22 at 20-50sccm. The cavity pressure is adjusted to 0.3-0.6Pa. The argon purity is ≥99.999%. The gas is preheated to 80°C (to prevent condensation). The pressure in the gas inlet barrel 21 is maintained at 0.5MPa. The flowmeter 22 is calibrated using NIST standard gas and automatically performs zero-point calibration every 24 hours. S3 low temperature alternating deposition: CrN layer deposition Open the target material inlet pipe 41 connected to the Cr target, feed the Cr target material through the injection hose 43, and control the opening of the sputtering nozzle 42 with the fourth solenoid valve 44. Adjust the volume ratio of the N2:Ar mixed gas to 1:3-1:5, the sputtering power to 200-300W, and the chamber temperature monitored by the second temperature sensor 13 at 150-250°C. Deposit a single layer of CrN with a thickness of 50-100nm. When the N2 ratio is greater than 1:3, the nitrogen content of the film increases to 45at% (XPS measurement), the hardness increases from 25GPa to 32GPa, but the internal stress increases to -2.5GPa (XRD measurement). A sputtering power of 250W is preferred for the best balance between deposition rate and stress. Al2O3 layer deposition Close the fourth solenoid valve 44 of the Cr target and switch to the Al target inlet pipe 41. A mixed gas of O2 and Ar is introduced in a volume ratio of 1:2-1:4, with a sputtering power of 150-250W and a temperature maintained at 150-250°C. Deposit a single layer of Al2O3 with a thickness of 20-50nm. When the O2 partial pressure is greater than 0.1Pa, the oxygen content of the Al2O3 film reaches 65at%, but the sputtering rate drops by 40%. Dynamically adjust the O2 flow rate using a PID algorithm to stabilize the deposition rate at 5nm / min±0.3nm / min. Inter-layer control The PLC controller 15 is programmed to repeat step S3, alternately depositing 10-20 layers of CrN / Al2O3, with a total film thickness of 1-2 μm. The thickness ratio of the CrN layer to the Al2O3 layer is 2-5:1, and during each layer deposition: cooling water is driven by the water pump 10 to flow through the spiral cooling tube 61 at a flow rate of 3-5 L / min; the semiconductor cooling plate 71 is set to a cooling temperature of 5-10°C, and the cooling fan 73 is forced to dissipate heat; the cavity temperature fluctuation is controlled by the PLC controller 15 within ±5°C; Film uniformity is achieved through the following linkage controls: The pressure sensor 14 monitors the cavity pressure in real time and feeds it back to the PLC controller 15 to dynamically adjust the opening of the first solenoid valve 24 and the second solenoid valve 26. The gas flow error is ≤±0.1sccm. The second temperature sensor 13 collects temperature data every 30 seconds. The PLC controller 15 adjusts the power of the semiconductor cooling plate 71 and the flow rate of the water pump 10 using the PID algorithm. The response time is ≤3 seconds. The sputtering power fluctuation is ≤±2%, and the film thickness deviation is ≤±5%. S4 post-processing: turn off the sputtering power supply, accelerate cooling through the spiral cooling tube 61 and the semiconductor refrigeration plate 71, and after the second temperature sensor 13 shows that the temperature is ≤50°C, open the pressure relief valve 52 to restore normal pressure and take out the coating substrate.

[0022] The present invention provides the following embodiments Example 1: Coating of aviation aluminum alloy precision parts Substrate: 7075-T6 aluminum alloy plate (size 150 mm × 80 mm × 3 mm), surface roughness Ra = 0.8 μm.

[0023] Preprocessing: 1. Alkaline degreasing: ultrasonic cleaning with 50g / L NaOH solution for 15 minutes (60°C); 2. Pickling activation: soak in HNO3 / HF mixed acid (3:1 volume ratio) for 3 minutes; 3. Plasma bombardment: Ar gas flow rate 20 sccm, -800 V bias treatment for 10 minutes.

[0024] Process parameters: Vacuum degree: 5×10⁻³Pa (molecular pump + vortex pump combined vacuuming); Deposition temperature: 180±5℃ (controlled by double-layer spiral water cooling + semiconductor refrigeration chip); CrN layer: Cr target power 250W, N2 / Ar=1:4, deposition rate 12.5nm / min, single layer 80nm; Al2O3 layer: Al target power 200W, O2 / Ar=1:3, deposition rate 6.8nm / min, single layer 40nm; Laminated structure: 15 layers are deposited alternately (total thickness 1.8 μm).

[0025] Performance testing: Hardness: 34.2GPa (nanoindentation method); Bonding force: Lc2=54.3N (scratch test); Salt spray resistance: no corrosion for 480h (5% NaCl); Thermal shock test: -55℃↔150℃ cycle 50 times without falling off.

[0026] Example 2: PEEK engineering plastic substrate coating Substrate: Victrex450G polyetheretherketone (PEEK) sheet (thickness 0.5 mm).

[0027] Preprocessing: 1. Ultrasonic cleaning in acetone for 10 minutes; 2. Oxygen plasma treatment: power 300 W, O2 flow rate 30 sccm, treatment for 5 minutes.

[0028] Process improvements: Pre-deposited Cr transition layer: 20nm thickness (80W low power sputtering); Temperature control strategy: semiconductor refrigeration chip forced cooling to 5℃, substrate temperature ≤150℃; Al2O3 layer optimization: O2 / Ar=1:4, sputtering power 150W, deposition rate 5.2nm / min.

[0029] Deposition parameters: Vacuum pumping time: 25 minutes (including pre-low vacuum stage); Gas mixing accuracy: flow meter error ≤ ±0.05sccm; Laminated structure: 20 alternating layers of CrN (50nm) / Al2O3 (25nm) (total thickness 1.5μm).

[0030] Performance Verification: Bonding force: 48N (critical load); Surface resistance: 9.8×10 5 Ω (ESD protection meets standards); Wear resistance: friction coefficient 0.21 (load 5N, UMT test); Thermal deformation: 0.018mm / m (150℃ thermal expansion test).

[0031] Example 3: WC-Co carbide tool coating Base material: Φ10 mm WC-8% Co end mill (surface roughness Ra = 0.1 μm).

[0032] Preprocessing: 1. Diamond grinding paste polishing to Ra ≤ 0.05μm; 2. Degrease with alcohol vapor for 30 minutes; 3. Ar ion etching: 1.2 Pa pressure, -1000 V bias, 15 minutes.

[0033] Key processes: Optimized layer thickness ratio: CrN (100nm) / Al2O3 (20nm) 5:1 structure; Gas efficiency enhancement: the introduction of Kr / Ar=1:5 mixed gas increases the sputtering efficiency by 40%; High-precision temperature control: PID algorithm control, temperature fluctuation ≤±3℃.

[0034] Deposition parameters: Vacuum degree: 4×10⁻³Pa (molecular pump ultimate vacuum); CrN layer: 300W pulse sputtering (frequency 40kHz), N2 / Ar=1:5; Al2O3 layer: 250W reactive sputtering, O2 / Ar=1:2; Total number of layers: 12 layers (thickness 1.44 μm).

[0035] Cutting test: Tool life: 380 minutes (TC4 titanium alloy, compared to 110 minutes for uncoated); Cutting temperature: 620℃ (real-time monitoring by infrared thermal imager); Surface quality: workpiece roughness Ra = 0.32μm (meeting mirror processing standards); Coating loss: Flank wear VB = 0.12 mm (ISO3685 standard).

[0036] Example 4: Flexible polyimide (PI) substrate coating Substrate: 50μm thick polyimide film (surface roughness Ra = 1.2μm), used for the encapsulation layer of flexible OLED display devices; Preprocessing: 1. Plasma activation: introduce Ar / H2 mixed gas (volume ratio 3:1) at 150W power for 3 minutes to increase the surface energy from 45mN / m to 72mN / m; 2. Ion beam cleaning: Use low-energy Ar⁺ beam (energy 50eV, beam current density 0.5mA / cm²) irradiation for 5 minutes to remove organic matter adsorbed on the surface.

[0037] Key process optimization: Ultra-low temperature control: The cooling water temperature in the water tank (9) is reduced to 5°C by using the semiconductor refrigeration sheet (71), and the spiral cooling tube (61) is used to force heat dissipation, so that the substrate temperature is stabilized at 120±5°C; Low-stress deposition: The CrN layer is deposited in pulsed sputtering mode (frequency 50kHz, duty cycle 30%) with a power of 180W to reduce thermal stress accumulation. Gradient transition layer: The first layer is deposited with 10nm pure Cr (power 80W, Ar flow rate 30sccm) to enhance the bonding strength between the film and the substrate.

[0038] Deposition parameters: Vacuum degree: 8×10⁻³Pa (the molecular pump is used for separate extraction to avoid vibration interference from the vortex pump); CrN layer: N2 / Ar mixed gas volume ratio 1:5, sputtering power 180W, deposition rate 8nm / min, single layer thickness 40nm; Al2O3 layer: O2 / Ar mixed gas volume ratio 1:4, sputtering power 150W, deposition rate 5nm / min, single layer thickness 20nm; Laminated structure: 25 layers are deposited alternately (total thickness of CrN is 1.0 μm, total thickness of Al2O3 is 0.5 μm), with a layer thickness ratio of 2:1; Performance Verification: 1. Flexibility: Bending radius 1mm, cycle 10 4After bending, there is no crack in the coating (SEM observation), and the critical load Lc2 = 42N (down by <5% compared with the unbent sample); 2. Barrier properties: Water vapor transmission rate (WVTR) ≤5×10⁻ 6 g / m² / day (38°C / 90%RH, MOCON tester); Oxygen transmission rate (OTR) ≤ 0.01cm³ / m² / day (ASTM D3985 standard); 3. Electrical characteristics: Surface resistance 1.2×10 8 Ω / sq (four-probe method, meeting ESD protection requirements); Dielectric constant 3.8 (1MHz), loss tangent 0.002 (measured by impedance analyzer); 4. Thermal stability: There is no delamination after heat treatment at 250℃ for 2 hours, and the barrier performance decay is less than 3% after aging at 85℃ / 85%RH for 1000 hours.

[0039] Technical effects: 1. Breakthrough in low-temperature compatibility: Deposition temperature is 120°C, 60% lower than the traditional CVD process (≥300°C), avoiding yellowing of the PI substrate (yellowing index ΔYI < 1.5); 2. Nano-laminated strengthening: The alternating structure of CrN / Al2O3 inhibits crack propagation, and the bending life is increased by 100% compared with single-layer Al2O3 (from 5×10³ times to 1×10 4 Second-rate); 3. Industrial efficiency: 25 layers of coating take a total of 3.8 hours (compared to 8-12 hours for CVD process), target utilization rate reaches 68%, and production costs are reduced by 40%.

[0040] Through the systematic implementation of the four embodiments, it is verified that the present invention has made breakthrough progress in the following core technological innovation dimensions: 1. Breakthrough in low-temperature process compatibility A 150-250°C low-temperature deposition process system has been successfully constructed, overcoming the bottleneck in the coating technology of heat-sensitive materials. In terms of material adaptability, this process is compatible with a variety of special substrates such as PEEK engineering plastics with a melting point as low as 143°C, flexible polyimide substrates with a thickness of only 50μm, and aviation-grade 7075-T6 aluminum alloy. Verification data shows that the hardness retention rate of the 7075 aluminum alloy substrate is ≥98% (HV185→182), and the thermal deformation of the PEEK material is controlled within 0.018mm / m, which is 3 orders of magnitude higher than the traditional high-temperature process. Through the coordinated temperature control of the double-layer water cooling system and semiconductor active refrigeration, the substrate temperature fluctuation is successfully controlled within the range of ±3°C, providing process guarantee for the manufacturing of precision medical devices.

[0041] 2. Nano-laminated structure performance optimization In terms of structural innovation, the CrN / Al2O3 nano-alternating deposition technology demonstrates a significant synergistic effect. The composite structure of 15-25 layers (total thickness 1-2μm) significantly transforms the overall performance of the coating: the hardness exceeds 34GPa (single-layer CrN is 25GPa), and the fracture toughness KIC value reaches 4.2MPa·m1 / 2, a 2.3-fold improvement over traditional single-layer structures. After a 480-hour 5% NaCl salt spray test, the sample surface showed no pitting corrosion, and the corrosion current density was as low as 1.2×10⁻ 8 A / cm², meeting the requirements of the GJB150.11A-2009 military standard. Specifically in tool applications, this structure increases the cutting life of TC4 titanium alloy to 380 minutes and reduces tool wear by 67%.

[0042] 3. Improved industrial production efficiency The equipment system achieves transformation for large-scale production through modular design. A novel magnetron target assembly configuration reduces the switching response time between Cr / Al dual targets to 8 seconds, increasing target utilization to 68% (compared to ≤50% for conventional processes). An innovative pulsed sputtering process stabilizes the deposition rate at 12.5nm / min, reducing energy consumption per unit area to 0.8kWh / μm·m², a 62% energy saving compared to conventional PVD processes. For a 25-layer coating process, the total production cycle is compressed to 3.8 hours, a 60% reduction compared to CVD technology. A single machine can produce six batches per day, laying the foundation for mass production of precision optical components.

[0043] 4. Intelligent control accuracy verification The PLC-based closed-loop control system demonstrates exceptional process stability. Validated across over 100 parameter sets, gas flow control accuracy reaches ±0.07 sccm (NIST traceable), and temperature fluctuations at a 0.5 Hz sampling frequency are ≤±1.5°C. An intelligent algorithm enables dynamic film thickness compensation, achieving a thickness deviation of <±4% after 15 alternating deposition layers (ISO14916 requires ±10%). In precision tool coating, cutting edge thickness consistency reaches ±0.8μm (Ra 0.05μm substrate), meeting the ISO13399 tool coating grading standard and providing reliable technical support for the manufacture of precision aerospace components.

[0044] The above are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. Low temperature dry plating CrN / Al2O3 nano-layer vacuum coating equipment, characterized in that: It includes a housing (1) and a gas injection assembly (2): Shell (1): an inner ring (12) is fixed inside, a placement rack (16) is fixed inside the inner ring (12), a second temperature sensor (13) and a pressure sensor (14) are installed at the rear end of the shell (1), a water tank (9) is fixed on the lower side of the shell (1), a water pump (10) is installed inside the water tank (9), a bracket (11) is fixed on the lower side of the shell (1), a PLC controller (15) is installed on the right side of the shell (1), a cooling component (6) is installed in the interlayer between the shell (1) and the inner ring (12), the cooling component (6) is connected to the water tank (9), a vacuum assembly (3) and a pressure relief assembly (5) are installed at the rear end of the shell (1), two symmetrical injection assemblies (4) are installed on the left and right ends of the upper end of the shell (1), a sealing assembly (8) is installed at the front end of the shell (1), a refrigeration assembly (7) is installed on the side of the water tank (9), and the refrigeration assembly (7) cooperates with the cooling assembly (6); An air injection assembly (2): comprising an air intake barrel (21), a flow meter (22), an air guide pipe (23), a first solenoid valve (24), an air intake pipe (25) and a second solenoid valve (26); an air injection hole is provided at the rear end of the housing (1); an air intake pipe (25) is fixed inside the air injection hole; a second solenoid valve (26) is installed on the circumferential surface of the air intake pipe (25); an air intake barrel (21) is fixed at the rear end of the housing (1); the rear end of the air intake pipe (25) is located inside the air intake barrel (21); a mounting hole is provided at the lower end of the circumferential surface of the air intake barrel (21); a flow meter (22) is installed inside the mounting hole; three corresponding air guide holes are provided at the rear end of the air intake barrel (21); an air guide pipe (23) is fixed inside the air guide hole; and a first solenoid valve (24) is installed on the circumferential surface of the air guide pipe (23); The input end of the PLC controller (15) is electrically connected to the output end of an external power supply, the output end of the PLC controller (15) is electrically connected to the input ends of the water pump (10), the first solenoid valve (24), and the second solenoid valve (26), respectively, and the PLC controller (15) is bidirectionally electrically connected to the flow meter (22), the second temperature sensor (13), and the pressure sensor (14).

2. The low-temperature dry-process CrN / Al2O3 nano-layer vacuum coating equipment according to claim 1, characterized in that: The vacuum pump assembly (3) comprises a vacuum pump (31), an exhaust pipe (32) and a third solenoid valve (33); the vacuum pump (31) is installed at the rear end of the housing (1); the exhaust pipe (32) is fixed inside the exhaust hole of the vacuum pump (31); the third solenoid valve (33) is installed on the circumferential surface of the exhaust pipe (32); the upper end of the exhaust pipe (32) is fixed inside the exhaust hole provided at the rear end of the housing (1); the input ends of the third solenoid valve (33) and the vacuum pump (31) are both electrically connected to the output end of the PLC controller (15).

3. The low-temperature dry-process CrN / Al2O3 nano-layer vacuum coating equipment according to claim 1, characterized in that: The injection assembly (4) includes a target material inlet pipe (41), a sputtering nozzle (42), an injection hose (43) and a fourth solenoid valve (44). Two corresponding target material inlet holes are provided at the upper end of the rear end of the housing (1). The target material inlet pipe (41) is fixed inside the target material inlet hole. The lower end of the circumferential surface of the target material inlet pipe (41) is installed with evenly distributed sputtering nozzles (42). The rear end of the target material inlet pipe (41) is fixed with an injection hose (43). The circumferential surface of the injection hose (43) is installed with a fourth solenoid valve (44). The input end of the fourth solenoid valve (44) is electrically connected to the output end of the PLC controller (15).

4. The low-temperature dry-process CrN / Al2O3 nano-layer vacuum coating equipment according to claim 1, characterized in that: The pressure relief assembly (5) comprises a pressure relief pipe (51) and a pressure relief valve (52). A pressure relief hole is provided at the rear end of the housing (1). The pressure relief pipe (51) is fixed inside the pressure relief hole. The pressure relief valve (52) is installed on the circumferential surface of the pressure relief pipe (51). The input end of the pressure relief valve (52) is electrically connected to the output end of the PLC controller (15).

5. The low-temperature dry-process CrN / Al2O3 nano-layer vacuum coating equipment according to claim 1, characterized in that: The cooling assembly (6) comprises a spiral cooling pipe (61), a water inlet pipe (62) and a water outlet pipe (63); the spiral cooling pipe (61) is sleeved on the circumferential surface of the inner ring (12); the water inlet pipe (62) is fixed inside the water inlet of the spiral cooling pipe (61); the water outlet pipe (63) is fixed inside the water outlet of the spiral cooling pipe (61); the water inlet pipe (62) is connected to the water outlet of the water pump (10); and the water outlet pipe (63) is connected to a reflux port provided on the side of the water tank (9).

6. The low-temperature dry-process CrN / Al2O3 nano-layer vacuum coating equipment according to claim 1, characterized in that: The refrigeration assembly (7) comprises a semiconductor refrigeration plate (71), a connecting frame (72), a heat dissipation fan (73), a protective net (74) and a first temperature sensor (75). A mounting groove is provided on the front side of the water tank (9), and a semiconductor refrigeration plate (71) is installed inside the mounting groove. The heat dissipation end of the semiconductor refrigeration plate (71) is located outside the mounting groove, and the cooling end of the semiconductor refrigeration plate (71) is located inside the mounting groove. A connecting frame (72) is fixed on the front side of the water tank (9), and two corresponding heat dissipation fans (73) are installed inside the connecting frame (72). Both heat dissipation fans (73) correspond to the semiconductor refrigeration plate (71). An opening is provided on the right side of the water tank (9), and a first temperature sensor (75) is installed inside the opening. The first temperature sensor (75) is bidirectionally electrically connected to the PLC controller (15). The input ends of the semiconductor refrigeration plate (71) and the heat dissipation fan (73) are electrically connected to the output end of the PLC controller (15).

7. The low-temperature dry-process CrN / Al2O3 nano-layer vacuum coating equipment according to claim 1, characterized in that: The sealing assembly (8) comprises a sealing cover (81), a sealing rubber ring (82) and a lock (83); the front end of the housing (1) is hingedly connected to the sealing cover (81); the rear end of the sealing cover (81) is fixed with a sealing rubber ring (82); the left end of the front end of the sealing cover (81) is equipped with a lock (83); and the lock (83) is connected to the front end of the housing (1).

8. The low-temperature dry-coating CrN / Al2O3 nano-layer vacuum coating process according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1 substrate pretreatment: ultrasonically clean the substrate to be coated to remove surface contaminants, dry it, and then fix it on a placement rack (16); S2 vacuum environment construction: Close the sealing cover (81) and start the lock (83), and use the vacuum pump (31) to evacuate the inner cavity of the housing (1) to a vacuum degree of ≤5×10⁻³Pa; Argon gas is introduced into the gas inlet barrel (21) through the gas guide tube (23), the gas flow rate is controlled by the flow meter (22) to be 20-50 sccm, and the cavity pressure is adjusted to 0.3-0.6 Pa; S3 low temperature alternating deposition: CrN layer deposition The target material inlet pipe (41) connected to the Cr target is opened, the Cr target material is transported through the injection hose (43), and the fourth solenoid valve (44) controls the sputtering nozzle (42) to open; The volume ratio of the N2 and Ar mixed gas is adjusted to 1:3-1:5, the sputtering power is 200-300W, the chamber temperature is monitored by the second temperature sensor (13) to be 150-250°C, and a single layer of CrN is deposited with a thickness of 50-100nm; Al2O3 layer deposition Close the fourth electromagnetic valve (44) of the Cr target, switch to the Al target material inlet pipe (41), introduce a mixed gas of O2 and Ar (volume ratio 1:2-1:4), sputter at a power of 150-250W, maintain the temperature at 150-250°C, and deposit a single layer of Al2O3 with a thickness of 20-50nm; Inter-layer control Step S3 is repeated by programming the PLC controller (15) to alternately deposit 10-20 layers of CrN / Al2O3 with a total film thickness of 1-2 μm; S4 post-processing: turn off the sputtering power supply, accelerate cooling through the spiral cooling tube (61) and the semiconductor refrigeration plate (71), and after the second temperature sensor (13) displays a temperature of ≤50°C, open the pressure relief valve (52) to restore normal pressure and remove the coating substrate.

9. The low-temperature dry-process CrN / Al2O3 nano-layer vacuum coating process according to claim 8, characterized in that: In step S3, the thickness ratio of the CrN layer to the Al2O3 layer is (2-5):1, and during the deposition of each layer: The cooling water is driven by a water pump (10) to flow through the spiral cooling tube (61) at a flow rate of 3-5 L / min; The semiconductor refrigeration chip (71) is set to a cooling temperature of 5-10°C, and the heat dissipation fan (73) is forced to dissipate heat; The cavity temperature fluctuation is controlled by the PLC controller (15) within ±5°C.

10. The low-temperature dry-plating CrN / Al2O3 nano-layer vacuum coating process according to claim 8, characterized in that: In step S3, the film uniformity is achieved through the following linkage control: The pressure sensor (14) monitors the cavity air pressure in real time and feeds back to the PLC controller (15) to dynamically adjust the opening of the first solenoid valve (24) and the second solenoid valve (26), with the gas flow error ≤±0.1sccm; The second temperature sensor (13) collects temperature data every 30 seconds, and the PLC controller (15) adjusts the power of the semiconductor refrigeration plate (71) and the flow rate of the water pump (10) through the PID algorithm, with a response time of ≤3 seconds; Sputtering power fluctuation ≤±2%, film thickness deviation ≤±5%.

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