Coating on inner surface of laser discharge cavity and method for preparing the same

Abstract

The application provides a laser discharge cavity inner surface coating and a preparation method thereof, and belongs to the technical field of plating. The method comprises the following steps: step S1, high-power pulse magnetron sputtering deposition plating is performed on a pretreated discharge cavity base material by using a NiCrAlHf alloy target, to obtain a discharge cavity base material after bottom layer plating; step S2, polystyrene microspheres are sprayed on the surface of the discharge cavity base material after bottom layer plating, and high-power pulse magnetron sputtering gradient plating is performed on the discharge cavity base material after bottom layer plating by using a NiCrAlHf alloy target and a yttrium oxide target, and then vacuum annealing treatment is performed, to obtain a discharge cavity base material after gradient plating; step S3, high-power pulse magnetron sputtering deposition plating is performed on the discharge cavity base material after gradient plating by using a yttrium oxide target, to obtain a discharge cavity base material after top layer plating, and then vacuum annealing treatment is performed, to obtain a laser discharge cavity inner surface coating. The application can achieve the purposes of erosion resistance and non-falling of the laser discharge cavity inner surface coating.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of plating, in particular to a laser discharge cavity inner surface plating layer and a preparation method thereof. BACKGROUND

[0002] The laser discharge cavity is subjected to a severe service environment under high-energy particle bombardment, high temperature and working gas chemical reaction. For example, when the discharge cavity of a quasi-molecule laser (such as a fluorine-based gas laser) works at a kilovolt-level high voltage and a kilohertz-level pulse frequency, the fluorine-containing working gas (such as ArF / KrF) will have an electrochemical reaction with the metal substrate (such as aluminum alloy or stainless steel) on the inner wall of the cavity, thereby generating solid fluorides or carbides impurities. These by-products and impurities will deteriorate the discharge stability, induce electric arc, and cause arc spots on the surface of the laser discharge cavity, thereby reducing the discharge stability and durability of the laser.

[0003] At present, the inner wall of the discharge cavity is mostly plated with nickel by chemical plating. However, the hydrogen evolution side reaction in the chemical plating process easily leads to pinholes in the plating layer, thereby increasing the porosity of the plating layer. When the corrosive medium penetrates, local microcells will be formed at the pinholes of the plating layer, which will accelerate the pitting corrosion of the plating layer and cause peeling, and finally expose and fail the cavity substrate.

[0004] The patent application file with the publication number CN113151791A discloses a method for rapidly depositing a silver plating film on the surface of an electrical contact material. The electrical contact substrate is placed in the sputtering cavity in the middle of the tubular sputtering source, and the inner wall of the sputtering cavity has a silver target layer. The sputtering cavity is vacuumized, then the process gas is introduced to a preset reverse sputtering cleaning gas pressure value, and reverse sputtering cleaning is performed. The process gas is adjusted to a sputtering plating gas pressure value, a sputtering voltage is applied between the tubular sputtering source and the electrical contact substrate, a bias voltage is applied between the electrical contact substrate and the upper and lower covers of the sputtering source, and the electrical contact substrate is driven to rotate, thereby performing bias sputtering plating. The electrical contact substrate is placed in the cylindrical sputtering source, so that the electrical contact substrate is located in the plasma discharge zone, thereby improving the deposition rate and target material utilization rate. At the same time, a negative bias voltage is applied to the electrical contact substrate during sputtering, which effectively guides the ion bombardment of the electrical contact substrate and the silver plating layer in the plasma discharge zone, thereby achieving the purpose of effectively improving the compactness and adhesion of the plating layer. Although this scheme improves the compactness and adhesion of the plating layer, the prepared plating film still has deficiencies in the anti-erosion ability in actual use.

[0005] Therefore, it is necessary to provide a laser discharge cavity inner surface plating layer and a preparation method thereof to solve the problems existing in the prior art. SUMMARY

[0006] Therefore, the application provides a laser discharge cavity inner surface coating and a preparation method thereof.

[0007] To achieve the above-mentioned purpose, the application provides a preparation method of a laser discharge cavity inner surface coating, comprising the following steps:

[0008] In step S1, a NiCrAlHf alloy target is used to perform high-power pulse magnetron sputtering deposition coating on the pretreated discharge cavity substrate to obtain a discharge cavity substrate after bottom layer coating.

[0009] In step S2, polystyrene microspheres are sprayed on the surface of the discharge cavity substrate after bottom layer coating, and a NiCrAlHf alloy target and a yttrium oxide target are used to perform high-power pulse magnetron sputtering gradient coating on the discharge cavity substrate after bottom layer coating, and then vacuum annealing treatment is performed to obtain a discharge cavity substrate after gradient coating.

[0010] In step S3, a yttrium oxide target is used to perform high-power pulse magnetron sputtering deposition coating on the discharge cavity substrate after gradient coating to obtain a discharge cavity substrate after top layer coating, and then vacuum annealing treatment is performed to obtain a laser discharge cavity inner surface coating.

[0011] The high-power pulse magnetron sputtering technology is used to perform deposition coating on the inner surface of the discharge cavity, the high ionization rate is realized by using the high pulse peak power and the low duty cycle, the peak power is 100 times of that of the ordinary magnetron sputtering, the plasma density is high, the large particles do not appear on the surface of the sputtering deposition coating, the high density of the coating can be realized, and the microstructure of the coating can be controlled, the internal stress of the coating is reduced, and the bonding force between the coating and the substrate is improved.

[0012] In the scheme, the NiCrAlHf alloy is used as the bottom layer coating, and Ni is used as the main component of the coating, the NiCrAlHf alloy has a high melting point and a low diffusion coefficient, can provide high-temperature structural stability for the coating, and the Ni can form a face-centered cubic structure substrate and has good ductility, can relieve thermal stress and reduce the cracking of the coating. Al and Cr can be oxidized to form aluminum oxide and chromium oxide, the aluminum oxide has a very low oxygen diffusion coefficient and can effectively block the inward diffusion of oxygen, the chromium oxide can resist the corrosion of the corrosion gas generated during the operation of the laser, and the corrosion resistance of the discharge cavity is improved. Hf is also introduced into the bottom layer coating, has a very high melting point, can improve the thermal stability of the coating, and has the function of pinning grain boundaries, can improve the bonding force of the aluminum oxide and the chromium oxide, promote the improvement of the adhesion strength of the coating, and avoid the peeling phenomenon.

[0013] The polystyrene microspheres are sprayed on the substrate of the discharge cavity during gradient plating, and nanoscale holes can be formed in the gradient plating layer during subsequent vacuum annealing, which can reduce the thermal conductivity and relieve the deformation of the plating layer caused by thermal stress, and improve the thermal shock resistance of the plating layer. The gradient plating layer can form the continuity of the thermal expansion coefficient values from the bottom layer to the top layer of the plating layer, play the role of smooth transition of the thermal expansion coefficient, avoid the cracking of the plating layer caused by thermal stress, and then make the corrosion elements penetrate the top layer of the plating layer and erode the bottom layer of the plating layer, and the phenomenon of peeling off the plating layer.

[0014] Yttrium oxide is used as the top layer of plating. During the laser discharge process, the probability of yttrium oxide atoms being sputtered off the surface under high-energy particle bombardment is much smaller than that of commonly used metals, and the resistance to plasma erosion is strong. The surface of yttrium oxide has less gas adsorption and low outgassing rate, which helps to maintain the stability of the vacuum degree in the discharge cavity. At the same time, the top layer of plating can cover the holes formed by the polystyrene microspheres during gradient plating, avoid the corrosion of the plating layer caused by the holes, and make the bonding force between the top layer of plating and the gradient plating layer stronger.

[0015] Finally, the vacuum annealing treatment of the plating layer can release the internal stress accumulated in the multi-layer deposition, promote the further interdiffusion between the interfaces of the layers, enhance the interlayer bonding force, and help to improve the integrity of the three layers of plating.

[0016] Preferably, in the step S1, the preparation step of pre-treating the discharge cavity substrate includes: polishing the discharge cavity substrate to make Ra≤0.8μm, sandblasting and roughening using alumina sand after cleaning, and then performing glow discharge to obtain the pre-treated discharge cavity substrate.

[0017] Preferably, the cleaning step includes: putting the polished discharge cavity substrate into acetone, ultrasonic treatment to remove oil, then immersing the discharge cavity substrate into anhydrous ethanol, ultrasonic treatment to remove organic matter, and finally washing with deionized water and blowing dry with nitrogen.

[0018] The discharge cavity substrate is pre-treated to completely remove grease, organic matter, oxides and small particle pollutants by using acetone, ethanol and deionized water, and then sandblasting and roughening is performed using alumina sand to form a uniform micron-level concave-convex structure on the surface of the discharge cavity, which significantly increases the actual contact area between the plating layer and the substrate, which is beneficial to providing a strong mechanical interlocking effect for the subsequent deposited plating layer, and can effectively improve the bonding strength between the plating layer and the surface of the discharge cavity.

[0019] Preferably, the mesh number of the alumina sand is 180-220 mesh.

[0020] Preferably, the preparation of the NiCrAlHf alloy target material comprises the following steps: weighing high-purity Ni, Cr, Al and Ni-Hf intermediate alloy according to the atomic ratio of Ni, Cr, Al and Hf as 60:15:23:2, melting and crushing into powder under argon protection, then sintering densification by hot isostatic pressing, annealing, cutting and polishing to obtain the NiCrAlHf alloy target material.

[0021] The preparation of the NiCrAlHf alloy target material is carried out in an oxygen-free environment to avoid oxidation of Al and Hf, and sintering densification by hot isostatic pressing eliminates pores and improves the densification degree of the target material.

[0022] Preferably, the high power of the high-power magnetron sputtering is 9-10 kW; in step S1, the pulse power of the magnetron sputtering deposition plating is 10 kW, the pulse width is 100 μs, the frequency is 500 Hz, the substrate bias is -100 V, the atmosphere is Ar, the gas pressure is 0.3 Pa, and the time is 3-4 h; in step S2, the temperature of the vacuum annealing treatment is 600-650℃, and the time is 1.5-2.5 h.

[0023] Preferably, the operation of the gradient plating comprises the following steps:

[0024] Step S21, sputtering plating according to the use amount of the NiCrAlHf alloy target material and the yttrium oxide target material in the metal atomic ratio of 7:3, the pulse power is 9 kW, the pulse width is 100 μs, the frequency is 1000 Hz, the bias is -120 V, the gas pressure is 0.35 Pa, the atmosphere is Ar / O2 mixed gas, and the time is 3-4 h;

[0025] Step S22, sputtering plating according to the use amount of the NiCrAlHf alloy target material and the yttrium oxide target material in the metal atomic ratio of 1:1, the gas pressure is 0.4 Pa, the time is 3-4 h, and the other conditions remain unchanged;

[0026] Step S23, sputtering plating according to the use amount of the NiCrAlHf alloy target material and the yttrium oxide target material in the metal atomic ratio of 3:7, the gas pressure is 0.5 Pa, the atmosphere is Ar / O2 mixed gas, the time is 4-5 h, and the other conditions remain unchanged, to complete the gradient plating.

[0027] The first step is to coat mainly with the NiCrAlHf alloy and introduce a small amount of yttrium oxide to form a composite structure coating layer with the metal matrix inlaid with yttrium oxide particles, and the thermal expansion coefficient value is close to the bottom layer coating; the second step is to use the same amount of NiCrAlHf alloy and yttrium oxide to form a continuous composite structure on the basis of the coating prepared in the first step, and the thermal expansion coefficient value is close to the coating formed in the first step; the third step is to use the NiCrAlHf alloy as an auxiliary and the yttrium oxide as a main part, and the thermal expansion coefficient value is close to the top layer coating.

[0028] Preferably, in the step S21, the molar ratio of Ar to O2 in the Ar / O2 mixed gas is 97:3; and in the step S23, the molar ratio of Ar to O2 in the Ar / O2 mixed gas is 95:5.

[0029] During the gradient coating process, oxygen is introduced into the atmosphere to ensure that the yttrium oxide is fully oxidized and deposited.

[0030] Preferably, in the step S3, an erbium oxide target is also used when the yttrium oxide target is used for high-power pulse magnetron sputtering deposition coating of the discharge cavity substrate.

[0031] The erbium oxide introduced in the top layer coating has high melting point and high stability, which can increase the stability of the coating. Moreover, the radius of erbium ion is matched with the radius of yttrium ion, which can form a stable solid solution with small lattice distortion, thereby reducing the sputtering weak point and further improving the erosion resistance of the coating. At the same time, the erbium oxide can improve the electrical conductivity of the top layer coating, avoid the influence of charge accumulation on the discharge uniformity, and reduce the risk of electric arc.

[0032] Preferably, the total atomic proportion of the erbium oxide target is 3%-5%.

[0033] To achieve the above-mentioned purposes, the application further provides a laser discharge cavity inner surface coating prepared by the preparation method of the laser discharge cavity inner surface coating.

[0034] The laser discharge cavity inner surface coating prepared by the scheme can realize strong erosion resistance, strong adhesion to the substrate, and the coating is not easy to fall off.

[0035] The above technical scheme of the application at least has the following beneficial effects:

[0036] 1. The high-power pulse magnetron sputtering technology can utilize higher pulse peak power and lower duty cycle to achieve high ionization rate, and the peak power is 100 times that of ordinary magnetron sputtering, the plasma density is high, which can realize high density of the coating and improve the adhesion between the coating and the substrate.

[0037] 2. The NiCrAlHf alloy is used as the bottom layer plating layer, which can provide high temperature structural stability for the plating layer, relieve thermal stress, reduce the cracking phenomenon of the plating layer, and improve the corrosion resistance of the discharge cavity; the pinning grain boundary effect of Hf promotes the improvement of the adhesion strength of the plating layer.

[0038] 3. The gradient plating layer forms the continuity of the thermal expansion coefficient values of the bottom layer plating layer to the top layer plating layer, plays a role of smooth transition, can avoid the cracking of the plating layer caused by thermal stress, and further makes the corrosion elements penetrate the top layer plating layer, corrode the bottom layer plating layer, and appear the peeling phenomenon of the plating layer. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme of the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. The described embodiments are part of the embodiments of the present application, and all other embodiments obtained by those skilled in the art based on the described embodiments of the present application belong to the scope of protection of the present application.

[0040] Embodiment 1

[0041] The discharge cavity substrate is polished to Ra≤0.8 μm, then the discharge cavity substrate is immersed in acetone, ultrasonic treatment is performed for 10 min, cleaning and oil removal are performed, then the discharge cavity substrate is immersed in anhydrous ethanol, ultrasonic treatment is performed for 15 min, cleaning and organic matter removal are performed, finally, 60℃ deionized water is used to rinse for 10 min, nitrogen blowing is performed to dry, and the cleaning operation is completed.

[0042] The discharge cavity substrate is sandblasted and roughened by using 180-220 mesh alumina sand, the surface roughness Ra is increased to 2-3 μm, finally, the plasma cleaning machine is used to perform glow discharge cleaning on the sandblasted and roughened discharge cavity substrate for 30 min, and the pretreated discharge cavity substrate is obtained.

[0043] High-purity Ni, Cr, Al and Ni-Hf intermediate alloy are weighed according to the atomic ratio of Ni, Cr, Al and Hf being 60:15:23:2, melted under the protection of argon, then the melt is crushed into a powder with a particle size of ≤75 μm, and hot isostatic pressing sintering is performed, the sintering temperature is 1200℃, the pressure is 125 MPa, finally, hot rolling, annealing and cutting and polishing are performed to obtain the NiCrAlHf alloy target material.

[0044] The NiCrAlHf alloy target material is used for high-power pulsed magnetron sputtering deposition plating on the pretreated discharge cavity substrate. The atomic ratio of Ni, Cr, Al and Hf in the NiCrAlHf alloy target material is 60:15:23:2. The pulse power is 10 kW, the pulse width is 100 μs, the frequency is 500 Hz, the substrate bias is -100 V, the atmosphere is Ar, the gas pressure is 0.3 Pa, and the deposition time is 3.5 h. The bottom layer plating is completed.

[0045] The polystyrene microspheres with a particle size of 90-110 nm are sprayed on the surface of the discharge cavity substrate after the bottom layer plating. The NiCrAlHf alloy target material and the yttrium oxide target material are used for gradient plating on the discharge cavity substrate after the bottom layer plating. In the first stage, the sputtering plating is carried out with the metal atomic ratio of the NiCrAlHf alloy target material to the yttrium oxide target material being 7:3. The power is 9 kW, the pulse frequency is 1000 Hz, the pulse width is 100 μs, the bias is -120 V, the gas pressure is 0.35 Pa, the atmosphere is Ar / O2 mixed gas, the ratio of Ar to O2 is 97:3, and the deposition time is 3 h. In the second stage, the sputtering plating is carried out with the metal atomic ratio of the NiCrAlHf alloy target material to the yttrium oxide target material being 1:1. The power, pulse width, pulse frequency, bias and atmosphere remain unchanged, the gas pressure is adjusted to 0.4 Pa, and the deposition time is 3.5 h. In the third stage, the sputtering plating is carried out with the metal atomic ratio of the NiCrAlHf alloy target material to the yttrium oxide target material being 3:7. The power, pulse width, pulse frequency and bias remain unchanged, the atmosphere is Ar / O2 mixed gas, the ratio of Ar to O2 is 95:5, the gas pressure is 0.5 Pa, and the deposition time is 5 h. The vacuum annealing treatment is carried out at 650 ℃ for 2 h, and the gradient plating is completed.

[0046] The top layer plating is carried out by using the yttrium oxide target material doped with 4% erbium oxide for sputtering. The power is 9 kW, the pulse width is 100 μs, the gas pressure is 0.45 Pa, the bias is -100 V, the atmosphere is Ar / O2 mixed gas, the ratio of Ar to O2 is 95:5, and the deposition time is 5 h. The top layer plating is completed.

[0047] The discharge cavity substrate after the magnetron sputtering is placed into a vacuum annealing furnace for post-treatment. The temperature is raised to 650 ℃ at a rate of 5 ℃ / min, the temperature is kept for 2 h, and then the temperature is slowly cooled to room temperature. The laser discharge cavity inner surface plating layer is obtained.

[0048] Example 2

[0049] The discharge cavity substrate is polished to Ra≤0.8 μm, then the discharge cavity substrate is immersed in acetone, ultrasonic treatment for 10 min, cleaning and degreasing, then the discharge cavity substrate is immersed in anhydrous ethanol, ultrasonic treatment for 15 min, cleaning and removing organic matter, finally the discharge cavity substrate is washed with 60℃ deionized water for 10 min, dried with nitrogen, and the cleaning operation is completed.

[0050] The discharge cavity substrate is sandblasted with 180-220 mesh alumina sand to increase the surface roughness Ra to 2-3 μm, and finally the sandblasted discharge cavity substrate is cleaned by glow discharge cleaning for 30 min using a plasma cleaning machine to obtain a pretreated discharge cavity substrate.

[0051] High-purity Ni, Cr, Al and Ni-Hf intermediate alloy are weighed according to the atomic ratio of Ni, Cr, Al and Hf of 60:15:23:2, melted under argon protection, then the melt is crushed into a powder with a particle size of ≤75 μm, and hot isostatic pressing sintering is performed, the sintering temperature is 1200℃, the pressure is 125 MPa, and finally hot rolling, annealing and cutting and polishing are performed to obtain a NiCrAlHf alloy target material.

[0052] The pretreated discharge cavity substrate is coated by high-power pulsed magnetron sputtering deposition using the NiCrAlHf alloy target material, the atomic ratio of Ni, Cr, Al and Hf in the NiCrAlHf alloy target material is 60:15:23:2, the pulse power in the process parameters is 10 kW, the pulse width is 100 μs, the frequency is 500 Hz, the substrate bias is -100 V, the atmosphere is Ar, the gas pressure is 0.3 Pa, and the deposition time is 4 h to complete the bottom coating.

[0053] The polystyrene microspheres with a particle size of 90-110 nm are sprayed on the surface of the base material of the discharge cavity after the bottom layer plating is completed, and the base material of the discharge cavity after the bottom layer plating is gradient plated by using the NiCrAlHf alloy target and the yttrium oxide target, in the first stage, the amount of the metal atom ratio of the NiCrAlHf alloy target and the yttrium oxide target is 7:3, the power is 9 kW, the pulse frequency is 1000 Hz, the pulse width is 100 μs, the bias voltage is-120 V, the gas pressure is 0.35 Pa, the atmosphere is the Ar / O2 mixed gas, the ratio of Ar and O2 is 97:3, and the deposition time is 3 h; in the second stage, the amount of the metal atom ratio of the NiCrAlHf alloy target and the yttrium oxide target is 1:1, the power, the pulse width, the pulse frequency, the bias voltage and the atmosphere are unchanged, the gas pressure is adjusted to 0.4 Pa, and the deposition time is 4 h; in the third stage, the amount of the metal atom ratio of the NiCrAlHf alloy target and the yttrium oxide target is 3:7, the power, the pulse width, the pulse frequency and the bias voltage are unchanged, the atmosphere is the Ar / O2 mixed gas, the ratio of Ar and O2 is 95:5, the gas pressure is 0.5 Pa, and the deposition time is 4 h, vacuum annealing treatment is carried out at 650℃ for 1.5 h, and the gradient plating is completed.

[0054] The top layer plating is carried out by using the yttrium oxide target doped with 3% erbium oxide for sputtering, the power is 9 kW, the pulse width is 100 μs, the gas pressure is 0.45 Pa, the bias voltage is-100 V, the atmosphere is the Ar / O2 mixed gas, the ratio of Ar and O2 is 95:5, the deposition time is 6 h, and the top layer plating is completed.

[0055] The base material of the discharge cavity after the magnetron sputtering is placed into a vacuum annealing furnace for post-treatment, the temperature is increased to 650℃ at a rate of 5℃ / min, the temperature is kept for 2 h, and then the temperature is slowly cooled to room temperature, and the laser discharge cavity inner surface coating is obtained.

[0056] Example 3

[0057] The base material of the discharge cavity is polished to make Ra≤0.8 μm, then the base material of the discharge cavity is immersed in acetone, ultrasonic treatment is carried out for 10 min, cleaning and oil removal are carried out, then the base material of the discharge cavity is put into anhydrous ethanol, ultrasonic treatment is carried out for 15 min, cleaning and organic matter removal are carried out, finally, deionized water at 60℃ is used to wash for 10 min, nitrogen blowing is carried out to dry, and the cleaning operation is completed.

[0058] The base material of the discharge cavity is sandblasted by using 180-220 mesh aluminum oxide sand to increase the surface roughness Ra to 2-3 μm, finally, the base material of the discharge cavity after the sandblasting is cleaned by using a plasma cleaning machine for glow discharge cleaning for 30 min, and the pretreated base material of the discharge cavity is obtained.

[0059] High-purity Ni, Cr, Al and Ni-Hf intermediate alloy are weighed according to the atomic ratio of 60:15:23:2, melted under argon protection, crushed into powder with particle size ≤75 μm, sintered by hot isostatic pressing method, sintering temperature is 1200 ℃, pressure is 125 MPa, and finally hot rolling, annealing, cutting and polishing are performed to obtain the NiCrAlHf alloy target material.

[0060] The NiCrAlHf alloy target material is used for high-power pulsed magnetron sputtering deposition plating on the pretreated discharge cavity substrate, the atomic ratio of Ni, Cr, Al and Hf in the NiCrAlHf alloy target material is 60:15:23:2, the pulse power in the process parameter is 10 kW, the pulse width is 100 μs, the frequency is 500 Hz, the substrate bias is -100 V, the atmosphere is Ar, the gas pressure is 0.3 Pa, and the deposition time is 4 h to complete the bottom layer plating.

[0061] Polystyrene microspheres with a particle size of 90-110 nm are sprayed on the surface of the discharge cavity substrate after the bottom layer plating, and the NiCrAlHf alloy target material and yttrium oxide target material are used for gradient plating on the discharge cavity substrate after the bottom layer plating, in the first stage, the NiCrAlHf alloy target material and the yttrium oxide target material are sputtered in a metal atomic ratio of 7:3, the power in the process parameter is 9 kW, the pulse frequency is 1000 Hz, the pulse width is 100 μs, the bias is -120 V, the gas pressure is 0.35 Pa, the atmosphere is Ar / O2 mixed gas, the ratio of Ar to O2 is 97:3, and the deposition time is 3.5 h; in the second stage, the NiCrAlHf alloy target material and the yttrium oxide target material are sputtered in a metal atomic ratio of 1:1, the power, pulse width, pulse frequency, bias and atmosphere in the process parameter remain unchanged, the gas pressure is adjusted to 0.4 Pa, and the deposition time is 3.5 h; in the third stage, the NiCrAlHf alloy target material and the yttrium oxide target material are sputtered in a metal atomic ratio of 3:7, the power, pulse width, pulse frequency and bias in the process parameter remain unchanged, the atmosphere is Ar / O2 mixed gas, the ratio of Ar to O2 is 95:5, the gas pressure is 0.5 Pa, and the deposition time is 5 h, vacuum annealing treatment is performed at 600 ℃ for 2.5 h to complete the gradient plating.

[0062] The top layer plating is performed by sputtering the yttrium oxide target material doped with 5% erbium oxide, the power in the parameter is 9 kW, the pulse width is 100 μs, the gas pressure is 0.45 Pa, the bias is -100 V, the atmosphere is Ar / O2 mixed gas, the ratio of Ar to O2 is 95:5, the deposition time is 4 h, and the top layer plating is completed.

[0063] The substrate in the discharge cavity after magnetron sputtering is put into a vacuum annealing furnace for post-processing, and is heated to 650℃ at a rate of 5℃ / min, and is slowly cooled to room temperature after being kept for 2h, to obtain the plated layer on the inner surface of the laser discharge cavity.

[0064] Example 4

[0065] The substrate in the discharge cavity is polished to Ra≤0.8μm, and then is immersed in acetone, and is ultrasonically treated for 10min for cleaning and removing oil, and then is immersed in anhydrous ethanol, and is ultrasonically treated for 15min for cleaning and removing organic matter, and finally is washed with 60℃ deionized water for 10min, and is dried with nitrogen, to complete the cleaning operation.

[0066] The substrate in the discharge cavity is sandblasted with 180-220 mesh alumina sand to increase the surface roughness Ra to 2-3μm, and finally is cleaned by glow discharge for 30min using a plasma cleaning machine, to obtain the pretreated substrate in the discharge cavity.

[0067] High-purity Ni, Cr, Al and Ni-Hf intermediate alloy are weighed according to the atomic ratio of Ni, Cr, Al and Hf of 60:15:23:2, and are smelted under argon protection, and then the melt is crushed into powder with a particle size of ≤75μm, and is sintered by hot isostatic pressing, with a sintering temperature of 1200℃ and a pressure of 125MPa, and finally is hot-rolled, annealed, cut and polished to obtain the NiCrAlHf alloy target material.

[0068] The pretreated substrate in the discharge cavity is coated by high-power pulsed magnetron sputtering using the NiCrAlHf alloy target material, with the atomic ratio of Ni, Cr, Al and Hf in the NiCrAlHf alloy target material being 60:15:23:2, the pulse power being 10kW, the pulse width being 100μs, the frequency being 500Hz, the substrate bias being-100V, the atmosphere being Ar, the gas pressure being 0.3Pa, and the deposition time being 3h, to complete the bottom coating.

[0069] The polystyrene microspheres with a particle size of 90-110 nm are sprayed on the surface of the base material of the discharge cavity after the bottom layer plating is completed, and the base material of the discharge cavity after the bottom layer plating is gradient plated by using the NiCrAlHf alloy target and the yttrium oxide target, in the first stage, the amount of the metal atom ratio of the NiCrAlHf alloy target and the yttrium oxide target is 7:3, the power is 9 kW, the pulse frequency is 1000 Hz, the pulse width is 100 μs, the bias voltage is-120 V, the gas pressure is 0.35 Pa, the atmosphere is the Ar / O2 mixed gas, the ratio of Ar and O2 is 97:3, and the deposition time is 4 h; in the second stage, the amount of the metal atom ratio of the NiCrAlHf alloy target and the yttrium oxide target is 1:1, the power, the pulse width, the pulse frequency, the bias voltage and the atmosphere are unchanged, the gas pressure is adjusted to 0.4 Pa, and the deposition time is 3 h; in the third stage, the amount of the metal atom ratio of the NiCrAlHf alloy target and the yttrium oxide target is 3:7, the power, the pulse width, the pulse frequency and the bias voltage are unchanged, the atmosphere is the Ar / O2 mixed gas, the ratio of Ar and O2 is 95:5, the gas pressure is 0.5 Pa, and the deposition time is 4.5 h, vacuum annealing treatment is carried out at 600 ℃ for 2 h, and the gradient plating is completed.

[0070] The top layer plating is carried out by using the yttrium oxide target doped with 4% erbium oxide for sputtering, the power is 9 kW, the pulse width is 100 μs, the gas pressure is 0.45 Pa, the bias voltage is-100 V, the atmosphere is the Ar / O2 mixed gas, the ratio of Ar and O2 is 95:5, the deposition time is 5.5 h, and the top layer plating is completed.

[0071] The base material of the discharge cavity after the magnetron sputtering is placed into a vacuum annealing furnace for post-treatment, the temperature is increased to 650 ℃ at a rate of 5 ℃ / min, the temperature is kept for 2 h, and then the temperature is slowly cooled to room temperature, and the plating layer on the inner surface of the laser discharge cavity is obtained.

[0072] Example 5

[0073] The base material of the discharge cavity is polished to make Ra≤0.8 μm, then the base material of the discharge cavity is immersed into acetone, ultrasonic treatment is carried out for 10 min, cleaning and oil removal are carried out, then the base material of the discharge cavity is put into anhydrous ethanol, ultrasonic treatment is carried out for 15 min, cleaning and organic matter removal are carried out, finally, deionized water at 60 ℃ is used to wash the base material of the discharge cavity for 10 min, nitrogen blowing is carried out to dry, and the cleaning operation is completed.

[0074] The base material of the discharge cavity is sandblasted by using 180-220 mesh aluminum oxide sand to increase the surface roughness Ra to 2-3 μm, finally, the base material of the discharge cavity after the sandblasting is cleaned by using a plasma cleaning machine for glow discharge cleaning for 30 min, and the pretreated base material of the discharge cavity is obtained.

[0075] High-purity Ni, Cr, Al and Ni-Hf intermediate alloy are weighed according to the atomic ratio of 60:15:23:2, melted under argon protection, crushed into powder with particle size of ≤75 μm, sintered by hot isostatic pressing method, sintering temperature is 1200 ℃, pressure is 125 MPa, and finally hot rolling, annealing, cutting and polishing are performed to obtain the NiCrAlHf alloy target material.

[0076] The NiCrAlHf alloy target material is used for high-power pulsed magnetron sputtering deposition plating on the pretreated discharge cavity substrate, the atomic ratio of Ni, Cr, Al and Hf in the NiCrAlHf alloy target material is 60:15:23:2, the pulse power in the process parameter is 10 kW, the pulse width is 100 μs, the frequency is 500 Hz, the substrate bias is -100 V, the atmosphere is Ar, the gas pressure is 0.3 Pa, and the deposition time is 4 h to complete the bottom layer plating.

[0077] Polystyrene microspheres with particle size of 90-110 nm are sprayed on the surface of the discharge cavity substrate after the bottom layer plating, and the NiCrAlHf alloy target material and yttrium oxide target material are used for gradient plating on the discharge cavity substrate after the bottom layer plating, in the first stage, the NiCrAlHf alloy target material and the yttrium oxide target material are sputtered in the proportion of 7:3, the power in the process parameter is 9 kW, the pulse frequency is 1000 Hz, the pulse width is 100 μs, the bias is -120 V, the gas pressure is 0.35 Pa, the atmosphere is Ar / O2 mixed gas, the ratio of Ar to O2 is 97:3, and the deposition time is 3.5 h; in the second stage, the NiCrAlHf alloy target material and the yttrium oxide target material are sputtered in the proportion of 1:1, the power, pulse width, pulse frequency, bias and atmosphere in the process parameter remain unchanged, the gas pressure is adjusted to 0.4 Pa, and the deposition time is 3.5 h; in the third stage, the NiCrAlHf alloy target material and the yttrium oxide target material are sputtered in the proportion of 3:7, the power, pulse width, pulse frequency and bias in the process parameter remain unchanged, the atmosphere is Ar / O2 mixed gas, the ratio of Ar to O2 is 95:5, the gas pressure is 0.5 Pa, and the deposition time is 4.5 h, vacuum annealing treatment is performed at 650 ℃ for 2 h to complete the gradient plating.

[0078] The top layer plating is performed, the yttrium oxide target material doped with 4.5% erbium oxide is sputtered, the power in the parameter is 9 kW, the pulse width is 100 μs, the gas pressure is 0.45 Pa, the bias is -100 V, the atmosphere is Ar / O2 mixed gas, the ratio of Ar to O2 is 95:5, the deposition time is 4.5 h, and the top layer plating is completed.

[0079] The substrate in the discharge cavity after magnetron sputtering is put into a high vacuum annealing furnace for post-processing, and is heated to 650 DEG C at a rate of 5 DEG C / min, and is slowly cooled to room temperature after being kept for 2 h, to obtain the plated layer on the inner surface of the laser discharge cavity.

[0080] Example 6

[0081] The substrate in the discharge cavity is polished to Ra≤0.8 μm, and then is immersed in acetone, and is ultrasonically treated for 10 min for cleaning and removing oil, and then is immersed in anhydrous ethanol, and is ultrasonically treated for 15 min for cleaning and removing organic matter, and finally is washed with 60 DEG C deionized water for 10 min, and is dried with nitrogen, to complete the cleaning operation.

[0082] The substrate in the discharge cavity is sandblasted with 180-220 mesh alumina sand to increase the surface roughness Ra to 2-3 μm, and finally is cleaned by glow discharge for 30 min using a plasma cleaning machine, to obtain the pretreated substrate in the discharge cavity.

[0083] High-purity Ni, Cr, Al and Ni-Hf intermediate alloy are weighed according to the atomic ratio of Ni, Cr, Al and Hf of 60:15:23:2, and are smelted under argon protection, and then the melt is crushed into powder with a particle size of ≤75 μm, and is sintered by hot isostatic pressing, with a sintering temperature of 1200 DEG C and a pressure of 125 MPa, and finally is hot-rolled, annealed, cut and polished to obtain the NiCrAlHf alloy target material.

[0084] The pretreated substrate in the discharge cavity is coated by high-power pulsed magnetron sputtering using the NiCrAlHf alloy target material, and the atomic ratio of Ni, Cr, Al and Hf in the NiCrAlHf alloy target material is 60:15:23:2, the pulse power in the process parameters is 10 kW, the pulse width is 100 μs, the frequency is 500 Hz, the substrate bias is -100 V, the atmosphere is Ar, the gas pressure is 0.3 Pa, and the deposition time is 4 h, to complete the bottom coating.

[0085] The polystyrene microspheres with a particle size of 90-110 nm are sprayed on the surface of the base material of the discharge cavity after the bottom layer plating, and the base material of the discharge cavity after the bottom layer plating is gradient plated by using the NiCrAlHf alloy target and the yttrium oxide target, in the first stage, the amount of the NiCrAlHf alloy target and the yttrium oxide target with a metal atom ratio of 7:3 is used for sputtering plating, the power is 9 kW, the pulse frequency is 1000 Hz, the pulse width is 100 mu s, the bias voltage is-120 V, the gas pressure is 0.35 Pa, the atmosphere is the Ar / O2 mixed gas, the ratio of Ar to O2 is 97:3, and the deposition time is 3.5 h; in the second stage, the amount of the NiCrAlHf alloy target and the yttrium oxide target with a metal atom ratio of 1:1 is used for sputtering plating, the power, the pulse width, the pulse frequency, the bias voltage and the atmosphere are unchanged, the gas pressure is adjusted to 0.4 Pa, and the deposition time is 3.5 h; in the third stage, the amount of the NiCrAlHf alloy target and the yttrium oxide target with a metal atom ratio of 3:7 is used for sputtering plating, the power, the pulse width, the pulse frequency and the bias voltage are unchanged, the atmosphere is the Ar / O2 mixed gas, the ratio of Ar to O2 is 95:5, the gas pressure is 0.5 Pa, and the deposition time is 4.5 h, vacuum annealing treatment is carried out at 650 DEG C for 2 h, and the gradient plating is completed.

[0086] The top layer plating is carried out by using the yttrium oxide target for sputtering, the power is 9 kW, the pulse width is 100 mu s, the gas pressure is 0.45 Pa, the bias voltage is-100 V, the atmosphere is the Ar / O2 mixed gas, the ratio of Ar to O2 is 95:5, the deposition time is 4.5 h, and the top layer plating is completed.

[0087] The base material of the discharge cavity after the magnetron sputtering is placed into a high-vacuum annealing furnace for post-treatment, the temperature is increased to 650 DEG C at a rate of 5 DEG C / min, the temperature is kept for 2 h, and then the temperature is slowly cooled to room temperature, so that the laser discharge cavity inner surface plating layer is obtained.

[0088] The present application also carries out comparative examples and related tests.

[0089] Comparative Example 1

[0090] The difference between Comparative Example 1 and Example 1 is that the NiCrAl target is used instead of the NiCrAlHf target in Comparative Example 1, and the other components and preparation methods are the same as those in Example 1, so that the laser discharge cavity inner surface plating layer is prepared.

[0091] Comparative Example 2

[0092] The difference between Comparative Example 2 and Example 1 is that the gradient plating is not carried out in Comparative Example 2, but the NiCrAlHf target and the yttrium oxide target with an atom ratio of 1:1 are directly used for sputtering plating, and the other components and preparation methods are the same as those in Example 1, so that the laser discharge cavity inner surface plating layer is prepared.

[0093] Comparative Example 3

[0094] Comparative Example 3 is different from Example 1 in that Comparative Example 3 uses ordinary sputtering plating, and other compositions and preparation methods are the same as those of Example 1, to prepare the inner surface plating layer of the laser discharge cavity.

[0095] Performance detection test

[0096] The inner surface plating layers of the laser discharge cavities prepared in Examples 1-6 and Comparative Examples 1-3 are heated to 800℃, and after holding for 10 min, they are put into 25℃ deionized water. After cooling and drying, it is checked whether the samples crack or fall off. The above operation is repeated until the samples crack and fall off obviously. The number of repetitions is recorded, and the thermal shock resistance performance test results are obtained. The test results are shown in Table 1 below.

[0097] The inner surface plating layers of the laser discharge cavities prepared in Examples 1-6 and Comparative Examples 1-3 are subjected to anti-electric erosion performance test and anti-corrosion performance test using a quasi-molecular laser with Ar / F2 mixed gas (the molar ratio of Ar to F2 is 95:5) as the working gas for 50 million pulses. The test results are shown in Table 1 below, taking arc spot density and fluorine corrosion thickness as the test results.

[0098] The inner surface plating layers of the laser discharge cavities prepared in Examples 1-6 and Comparative Examples 1-3 are subjected to adhesion strength test using ASTM C1624-05 as the test standard. The load at which the first obvious peeling occurs is taken as the result. The test results are shown in Table 1 below.

[0099] Table 1

[0100]

[0101] As can be seen from Table 1 above, compared with the inner surface plating layer of the laser discharge cavity prepared in Example 5, the inner surface plating layer of the laser discharge cavity prepared in Comparative Example 1 has a certain gap in thermal shock resistance and a relatively obvious gap in adhesion strength, indicating that the addition of Hf can improve the thermal stability of the plating layer and improve the adhesion strength of the plating layer. The inner surface plating layer of the laser discharge cavity prepared in Comparative Example 2 has a large gap in thermal shock resistance compared with the inner surface plating layer of the laser discharge cavity prepared in Example 5, indicating that gradient plating helps to form a stable transition in the thermal expansion coefficient between the bottom layer plating layer, the gradient plating layer and the top layer plating layer, improve the thermal shock resistance of the overall plating layer, and avoid cracking and peeling of the plating layer. The inner surface plating layer of the laser discharge cavity prepared in Comparative Example 3 has a gap in various performances compared with the inner surface plating layer of the laser discharge cavity prepared in Example 5, indicating that high-power magnetron sputtering plating can make the performance of the plating layer better.

[0102] Compared with Example 5, Example 6 does not use erbium oxide when performing top layer plating, and the arc spot density and fluorine etching depth are obviously increased, indicating that erbium oxide can enhance the etching resistance of the plating layer.

[0103] The above is the preferred embodiment of the present application, and those skilled in the art can make several improvements and refinements without departing from the principles of the present application, and these improvements and refinements should also be considered within the scope of protection of the present application.

Claims

1. A method of producing a coating on the inner surface of a discharge chamber of a laser, characterized in that The method comprises the following steps: Step S1, using a NiCrAlHf alloy target to perform high-power pulse magnetron sputtering deposition plating on a pretreated discharge cavity substrate to obtain a bottom-layer plated discharge cavity substrate; Step S2, spraying polystyrene microspheres on the surface of the bottom-layer plated discharge cavity substrate, and using a NiCrAlHf alloy target and a yttrium oxide target to perform high-power pulse magnetron sputtering gradient plating on the bottom-layer plated discharge cavity substrate, and then performing vacuum annealing treatment to obtain a gradient-plated discharge cavity substrate; Step S3, using an yttrium oxide target doped with erbium oxide to perform high-power pulse magnetron sputtering deposition plating on the gradient-plated discharge cavity substrate to obtain a top-layer plated discharge cavity substrate, and then performing vacuum annealing treatment to obtain a laser discharge cavity inner surface plating layer; The gradient plating operation comprises the following steps: Step S21, performing sputtering plating according to the use amount of the metal atom ratio of the NiCrAlHf alloy target to the yttrium oxide target being 7:3, the pulse power being 9kW, the pulse width being 100μs, the frequency being 1000Hz, the bias voltage being-120V, the gas pressure being 0.35Pa, the atmosphere being Ar / O2 mixed gas, and the time being 3-4h; Step S22, performing sputtering plating according to the use amount of the metal atom ratio of the NiCrAlHf alloy target to the yttrium oxide target being 1:1, the gas pressure being 0.4Pa, the time being 3-4h, and other conditions being unchanged; Step S23, performing sputtering plating according to the use amount of the metal atom ratio of the NiCrAlHf alloy target to the yttrium oxide target being 3:7, the gas pressure being 0.5Pa, the atmosphere being Ar / O2 mixed gas, the time being 4-5h, and other conditions being unchanged, to complete the gradient plating.

2. The method for preparing a coating on the inner surface of a discharge chamber of a laser as claimed in claim 1, characterized in that, In the step S1, the preparation step of the pretreated discharge cavity substrate comprises: polishing the discharge cavity substrate so that Ra≤0.8μm, performing sand blasting roughening on the polished discharge cavity substrate using alumina sand after cleaning, and then performing glow discharge to obtain the pretreated discharge cavity substrate.

3. The method of claim 2, wherein the laser discharge chamber inner surface coating is prepared by, The cleaning step comprises: placing the polished discharge cavity substrate into acetone, performing ultrasonic treatment to remove oil, immersing the discharge cavity substrate into anhydrous ethanol, performing ultrasonic treatment to remove organic matter, and finally washing with deionized water and blowing dry with nitrogen.

4. The method of claim 2, wherein the laser discharge chamber inner surface coating is prepared by, The mesh number of the alumina sand is 180-220.

5. The method of claim 1, wherein the laser discharge chamber inner surface coating is prepared by the steps of: a) providing a laser discharge chamber inner surface; b) providing a coating material; c) providing a coating material applicator; d) applying the coating material to the laser discharge chamber inner surface; and e) curing the coating material. The preparation of the NiCrAlHf alloy target comprises the following steps: weighing high-purity Ni, Cr, Al and Ni-Hf intermediate alloy according to the atomic ratio of Ni:Cr:Al:Hf being 60:15:23:2, melting and crushing into powder under argon protection, sintering densification by using hot isostatic pressing method, annealing, cutting and polishing to obtain the NiCrAlHf alloy target.

6. The method of claim 1, wherein the method further comprises: The high power of the high-power magnetron sputtering is 9-10kW; in step S1, the pulse power of the magnetron sputtering deposition plating is 10kW, the pulse width is 100us, the frequency is 500Hz, the substrate bias is-100V, the atmosphere is Ar, the gas pressure is 0.3Pa, and the time is 3-4h; in step S2, the temperature of the vacuum annealing treatment is 600-650℃, and the time is 1.5-2.5h.

7. The method of claim 1, wherein the laser discharge chamber inner surface coating is prepared by a process comprising: In step S21, the molar ratio of Ar to O2 in the Ar / O2 mixed gas is 97:3; in step S23, the molar ratio of Ar to O2 in the Ar / O2 mixed gas is 95:

5.

8. A coating for the interior surface of a laser discharge chamber, characterized in that The laser discharge cavity inner surface coating is prepared by the method in any one of the preceding claims 1-7.

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