Preparation method of nuclear super-thick Zr / Ti / Ti35 corrosion-resistant coating

Abstract

The application discloses a preparation method of a nuclear super-thick Zr / Ti / Ti35 corrosion-resistant coating, and comprises the following steps: 1, installing a nuclear-grade target material in a coating machine; 2, sandblasting, ultrasonic cleaning and blow-drying a base material, and then loading the base material into the coating machine for pretreatment; 3, vacuumizing the coating machine loaded with the pretreated base material, and then cleaning to obtain a clean base material; and 4, sequentially depositing a Zr metal transition layer and a Ti / Ti35 corrosion-resistant functional layer on the clean base material to obtain a super-thick Zr / Ti / Ti35 corrosion-resistant coating on the surface of the clean base material. The super-thick Zr / Ti / Ti35 coating prepared by using the physical vapor deposition technology has a uniform and dense structure and few integral defects, can produce a surface protection effect on low-cost and non-corrosion-resistant base materials in a boiling concentrated strong acid corrosion medium for more than 30 years, greatly reduces the cost of a nuclear material main body, and is suitable for nuclear chemical engineering and can be popularized to surface strengthening of civil materials.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of nuclear chemical engineering and surface treatment, and particularly relates to a preparation method of a nuclear super-thick Zr / Ti / Ti35 corrosion-resistant coating. BACKGROUND

[0002] Physical vapor deposition is an advanced surface treatment technology widely used in the world at present. Its working principle is that under vacuum conditions, gas discharge is used to make gas or evaporated substances partially ionize, and the evaporated substances or their reaction products are deposited on the substrate under the bombardment of gas ions or evaporated substance ions. It has the characteristics of fast deposition speed and clean surface, and has the advantages of strong adhesion of the film layer, good flexibility, and wide range of materials that can be plated.

[0003] In recent years, with the large-scale development and utilization of nuclear energy, the disposal of high-temperature and strong-radiation spent nuclear fuel by landfill has been unable to meet the requirements of the new era. The use of Purex process organic extractant to extract and separate uranium and plutonium in spent fuel for recycling has become the main scheme for handling large amounts of spent fuel by nuclear powers. The nuclear chemical engineering field involved faces many challenges, among which corrosion of equipment materials is a key problem that hinders the development of the field and needs to be solved urgently. The nuclear chemical engineering containers used in spent fuel reprocessing, such as dissolvers and evaporators, need to be in service for the entire life cycle in harsh environments of high temperature, strong nitric acid, and strong radiation. Once corrosion penetration occurs, the consequences will be disastrous, not only delaying the annual spent fuel processing schedule, but also posing a serious threat to the safety of maintenance personnel in the radioactive equipment environment. Therefore, ensuring the safety and reliability of related equipment during operation is the primary goal.

[0004] Currently, international research and development of materials for spent fuel reprocessing equipment mainly focuses on stainless steel, titanium alloy, and zirconium alloy. European countries such as the United Kingdom and Germany use ultra-low carbon stainless steel, Japan and India use Ti-Ta titanium alloy, France uses optimized zirconium-based alloy, and China currently uses Ti35 as the preferred corrosion-resistant titanium alloy, which has been successfully applied to the second phase of the spent fuel reprocessing demonstration project with an annual processing capacity of 200 tons. This alloy has been verified for a long time to have excellent corrosion resistance to nitric acid, and has strong corrosion resistance in the working liquid. The corrosion resistance is mainly due to the addition of tantalum, which forms a stable and super-corrosion-resistant TiO2 and Ta2O5 double passivation film on the alloy surface. However, tantalum is relatively expensive, and even the nuclear industry cannot afford its high price. Therefore, advanced surface treatment technology can be considered to be used to prepare a super-corrosion-resistant Ti35 alloy coating material on the surface of low-cost 316 stainless steel or low-cost titanium alloy to replace some secondary key components, significantly reducing costs.

[0005] In complex spent fuel reprocessing environments, protective coatings on equipment surfaces need to reach a certain thickness to meet operational requirements. This is because thin films contain numerous penetrating defects, including microscopic defects such as vacancies, dislocations, and stacking faults, and macroscopic defects such as pinholes, droplets, grain boundaries, cracks, and uneven microstructure. These defects degrade film performance, thereby accelerating the corrosion rate of the substrate. Ultra-thick coatings can bridge and prevent the interconnection of defects, reduce their presence, enhance the barrier effect of high-coating materials against corrosive media, and significantly improve their corrosion resistance.

[0006] Using Ti35 as a coating is a new idea that extends the excellent corrosion resistance of the alloy. It can not only maintain the structural dimensional stability and integrity of the main material without modifying existing production equipment and manufacturing processes, but also significantly improve the corrosion resistance of the high alloy material surface. This provides a brand-new approach for the design of spent fuel reprocessing structural materials in my country.

[0007] Therefore, a method for preparing an ultra-thick Zr / Ti / Ti35 corrosion-resistant coating for nuclear applications is needed. Summary of the Invention

[0008] The technical problem to be solved by this invention is to address the shortcomings of the prior art by providing a method for preparing an ultra-thick Zr / Ti / Ti35 corrosion-resistant coating for nuclear applications. This method utilizes physical vapor deposition (PVD) technology to prepare a thick Zr / Ti / Ti35 coating with a uniform and dense microstructure and few overall penetration defects. It can provide surface protection for low-cost, non-corrosion-resistant substrate materials for over 30 years in boiling concentrated strong acid corrosive media, significantly reducing the cost of nuclear materials. This method is not only applicable to nuclear chemical engineering but can also be extended to surface strengthening of engineering structural materials in civilian chemical fields such as corrosion-resistant tanks and pipelines.

[0009] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for preparing an ultra-thick Zr / Ti / Ti35 corrosion-resistant coating for nuclear applications, characterized by comprising the following steps:

[0010] Step 1: Install nuclear-grade Zr target, nuclear-grade Ti target, and nuclear-grade Ti35 target into the coating machine to obtain a coating machine containing the targets;

[0011] Step 2: The substrate is sandblasted, ultrasonically cleaned and dried in sequence. Then, it is loaded into the coating machine containing the target material obtained in Step 1 through tooling fixtures to pre-treat the substrate, thus obtaining a coating machine containing the pre-treated substrate.

[0012] Step 3: After vacuuming the coating machine containing the pretreated substrate obtained in Step 2, the pretreated substrate is cleaned to obtain a clean substrate; the cleaning is high bias bombardment cleaning or IET etching cleaning.

[0013] Step 4: Sequentially deposit a Zr metal transition layer and a Ti / Ti35 corrosion-resistant functional layer on the clean substrate obtained in Step 3 to obtain an ultra-thick Zr / Ti / Ti35 corrosion-resistant coating on the surface of the clean substrate.

[0014] This application, which transforms alloy materials into films, must consider the compatibility and matching between the film material and the substrate material at the interface, and also address the bombardment stress introduced into the film during physical vapor deposition. Therefore, a non-ferrous metal Zr is introduced as a transition layer, as well as a Ti metal layer, gradient layer, and cyclic layer to alleviate the compressive stress of the Ti35 main layer. Thus, this application uses Zr as the base layer, i.e., the transition layer. Zirconium metal has strong bonding force and can form a strongly bonded alloy layer with stainless steel and titanium alloy substrates under the bombardment of high-energy particle streams. Ti is used as a composition gradient layer or modulated cyclic layer to alleviate the ion bombardment stress experienced by the Ti35 main layer during deposition, while also enhancing the compatibility and matching between the film and the substrate material at the interface. Zirconium and titanium are both elements in the same subgroup (IVB) of the periodic table and have similar physicochemical properties. They can form an infinite solid solution with a close-packed hexagonal structure at room temperature, which plays a positive role in bonding the transition layer and the main functional layer. The Ti35 main layer is mainly used for corrosion resistance in high-temperature, high-energy concentrated nitric acid environments.

[0015] The above-mentioned method for preparing an ultra-thick Zr / Ti / Ti35 corrosion-resistant coating for nuclear applications is characterized in that, in step one, the nuclear-grade Zr target, nuclear-grade Ti target, and nuclear-grade Ti35 target are all high-density targets prepared by hot isostatic pressing or spraying. The coating machine containing the targets is equipped with 4 to 20 sets of nuclear-grade Ti35 targets, 2 to 5 sets of nuclear-grade Zr targets, and 2 to 10 sets of nuclear-grade Ti targets. The mass purity of the nuclear-grade Zr target, nuclear-grade Ti target, and nuclear-grade Ti35 target is not less than 99.9%. The high-density target material in this invention is close to the theoretical density of each metal material. However, due to differences in preparation processes and methods, a completely dense alloy state without any voids cannot be formed. For example, low pressure can lead to incomplete removal of pores or defects, and the use of spherical powder in target pressing results in numerous pores. Furthermore, targets prepared using traditional methods such as smelting often have coarse grains and many impurities, which are generally not accepted in the coating field. Therefore, this invention generally uses hot isostatic pressing (HIP) to prepare the target material, but for a few types of materials, only spraying can be used. In this invention, titanium alloys and zirconium alloys are available in industrial and nuclear grades. The raw materials are industrial-grade sponge titanium or industrial-grade sponge zirconium, nuclear-grade sponge titanium, and nuclear-grade sponge zirconium. Industrial-grade materials are primarily used in civilian facilities with less complex operating conditions, and the requirements for trace elements such as O, C, N, and H are relatively narrow. While the requirements are lenient, the titanium and zirconium alloys used in nuclear power plants suffer significant damage from the harsh operating environment under various radiation exposures. Trace element control within these materials is extremely stringent. Therefore, this invention employs nuclear-grade Zr, nuclear-grade Ti, and nuclear-grade Ti35 targets. In this invention, "each group" refers to one arc source or plasma generator. Each device supports only one target because the arc sources are uniformly distributed on the furnace wall. For large substrates or numerous substrates, the distribution coverage area of ​​each arc source needs to be considered. Zr is used for the undercoating. For example, if there are four rows of arc sources in the furnace, a Zr target is placed at a different height in each row, thus achieving full-height Zr plating. Similarly, Ti and Ti35 targets are placed at different heights. Since the Zr targets used for undercoating have a small working time, their number should be limited. Ti and Ti35 targets can be mixed in different proportions depending on the gradient layer or cyclic layer design.

[0016] The above-mentioned method for preparing an ultra-thick Zr / Ti / Ti35 corrosion-resistant coating for nuclear applications is characterized in that, in step two, the substrate is nuclear-grade stainless steel, nuclear-grade titanium alloy, or nuclear-grade zirconium alloy; the substrate is fixed on a two-dimensional or three-dimensional rotating sample holder within the vacuum chamber of the coating machine; and the pretreatment process involves maintaining a target-substrate distance of 150mm~270mm and evacuating the vacuum chamber of the coating machine to a back-bottom vacuum degree of 7.0×10⁻⁶. -4 Pa ~ 5.0 × 10 -3Pa, adjust the motor speed of the sample holder to 2 r / min~7 r / min, heat the vacuum chamber to 100℃~350℃ and hold for 1h~3h. In this invention, the target-substrate distance is maintained at 150mm~270mm to ensure a moderate particle density and energy density of the plasma flow, avoiding excessive energy and slow deposition rate due to excessive distance. The vacuum chamber is evacuated to a back-bottom vacuum level of 7.0×10⁻⁶. -4 Pa ~ 5.0 × 10 -3 Pa, high vacuum is beneficial to remove oxygen and other polluting gases in the furnace. Adjust the rotation speed of the rotating frame motor to 2r / min~7r / min. The appropriate rotating frame speed is beneficial to the full exposure and cooling of the substrate during the coating process, avoids stress accumulation, and ensures sufficient film exposure time. The substrate is heated to 100℃~350℃ in the vacuum chamber and fully baked for 1h~3h to further remove surface contaminants, thereby improving the activation energy of the substrate surface.

[0017] The above-mentioned method for preparing an ultra-thick Zr / Ti / Ti35 corrosion-resistant coating for nuclear applications is characterized in that the high-bias bombardment cleaning or IET etching cleaning process in step three is as follows: high-purity argon gas is introduced into the vacuum chamber of the coating machine and the vacuum degree is maintained at 0.5Pa~3Pa. A high-frequency high-voltage arc ignition or mechanical arc ignition is used to ignite the nuclear-grade Zr target material, with an arc target current of 80A~200A. A bias voltage of -600V~-800V is applied to the substrate, with a duty cycle of 60%~80%, and a cleaning time of 10min~30min, reducing the surface layer thickness of the substrate by 20nm~600nm; the purity of the argon gas is not less than 99.99%. This invention further removes contaminants from the substrate surface, activates the surface, and removes the nanoscale thickness oxide layer through high-bias bombardment cleaning or IET etching cleaning.

[0018] The above-mentioned method for preparing an ultra-thick Zr / Ti / Ti35 corrosion-resistant coating for nuclear applications is characterized in that the process of depositing the Zr metal transition layer and the Ti / Ti35 corrosion-resistant functional layer in step four is as follows:

[0019] Step 101: High-purity argon gas is introduced into the vacuum chamber of the coating machine and the vacuum degree is maintained at 0.5Pa~3Pa. The nuclear-grade Zr target material is ignited by mechanical arc ignition or high-frequency high-voltage arc ignition, the current is 80A~150A, the bias voltage is adjusted to -100V~-150V, the duty cycle is 40%~60%, and the deposition time is 5min~30min to obtain a Zr metal transition layer with a thickness of 300nm~2μm.

[0020] Step 102: Extinguish the nuclear-grade Zr targets one by one and turn on the corresponding nuclear-grade Ti targets one by one, while maintaining an arc current of 80A~200A, a bias voltage of -80V~-150V, a duty cycle of 20%~80%, and a deposition time of 2min~30min to obtain a Ti layer with a thickness of 500nm~5μm.

[0021] Step 103: Adjust the parameters of the nuclear-grade Ti target and the nuclear-grade Ti35 target, and deposit for a total of 3h~12h to obtain an ultra-thick Zr / Ti / Ti35 coating with a thickness of 10μm~40μm. This invention maintains an argon environment of 0.5Pa~3Pa, which is beneficial to ensure the rapid movement and complete combustion of the target arc spot. By controlling the parameters for preparing the Zr metal transition layer, continuous bombardment is ensured, reducing stress accumulation, and a Zr metal transition layer with a thickness of 300nm~2μm is obtained. When the transition layer process is about to be completed, this invention does not recommend completely shutting down the Zr target and then completely turning on the Ti target. It is best to turn on the nuclear-grade Ti target in equal numbers, that is, extinguishing one Zr target while simultaneously turning on one Ti target, then turning off another, then turning on another, and so on, gradually shutting down and gradually turning on, gradually transitioning from the Zr layer to the Ti layer, ensuring the connection effect between the Zr metal transition layer and the Ti layer. Similarly, it also ensures the connection effect between the Ti layer and the Ti35 layer. By controlling the parameters, continuous use of high bias voltage is ensured to prevent stress accumulation.

[0022] The above-mentioned method for preparing an ultra-thick Zr / Ti / Ti35 corrosion-resistant coating for nuclear applications is characterized in that the deposition process in step 103 is as follows: extinguishing the nuclear-grade Ti target, opening the nuclear-grade Ti35 target to deposit a Ti35 gradient layer, decreasing the bias voltage from -120V to -140V every 10min to 50min by -3V to -5V until -80V, or conversely increasing the bias voltage, i.e., increasing the bias voltage from -80V every 10min to 50min by -3V to -5V until -120V to -140V, increasing the duty cycle from 20% every 10min to 50min by 2% to 5% until 60% to 80%, or conversely decreasing the duty cycle, i.e., decreasing the duty cycle from 60% to 80% every 10min to 50min by 2% to 5% until 20%. In this invention, the bias voltage and duty cycle are changed simultaneously, but two combinations are given in this step: 1. When the bias voltage is gradually decreased, the duty cycle is gradually increased; 2. When the bias voltage is gradually increased, the duty cycle is gradually decreased. The reason is that the product of bias voltage and duty cycle represents the energy density acting on the coating surface per unit time. When both bias voltage and duty cycle are large, the energy will be high, which will heat the surface, and the film deposition will also be bombarded by high energy, resulting in a large accumulation of internal stress. Therefore, both must not be at large values ​​at the same time, and they need to be increased or decreased in combination. In this invention, a process gradient layer is prepared under this parameter. By adjusting the bias voltage and duty cycle in combination, gradually increasing or decreasing them, the stress and defects inside the overall film layer can be gradually released.

[0023] The above-mentioned method for preparing an ultra-thick Zr / Ti / Ti35 corrosion-resistant coating for nuclear applications is characterized in that the deposition process in step 103 is as follows: extinguishing the nuclear-grade Ti target, setting the arc current of the nuclear-grade Ti35 target to 150A~200A, and cyclically changing the bias voltage from -80V to -140V and the duty cycle from 20% to 80% 1 to 5 times. Each cycle involves increasing the bias voltage from -2V to -5V every 3 to 5 minutes until it reaches -140V, then decreasing it from -2V to -5V every 3 to 5 minutes until it reaches -80V, and increasing the duty cycle from 20% from 2% to 60% to 80% every 3 to 5 minutes, then decreasing it from 2% to 20% every 3 to 5 minutes. The cycle period for each cycle is 90 to 300 minutes. In this invention, the parameters are used to form a process cycle layer. High bias voltage and high duty cycle can obtain a dense and hard layer, while low bias voltage and low duty cycle can obtain a softer layer. After the cycle layer is formed, the alternation between soft and hard layers can bridge defects and prevent the propagation of microcracks.

[0024] The above-mentioned method for preparing an ultra-thick Zr / Ti / Ti35 corrosion-resistant coating for nuclear applications is characterized in that the deposition process in step 103 is as follows: The nuclear-grade Ti target is extinguished, and the nuclear-grade Ti35 target is turned on with an arc current of 120A~200A, a bias voltage of -80~-140V, and a duty cycle of 20%~90% to deposit a Ti35 coating for 5min~15min. Then, the nuclear-grade Ti35 target is turned off, and the nuclear-grade Ti target is turned on again with an arc current of 120A~200A, a bias voltage of -80~-140V, and a duty cycle of 20%~90% to deposit a Ti layer for 2min~10min. This process is repeated 5~100 times. In this invention, the Ti target and Ti35 target are set to alternately operate at full on and full off, without gradually extinguishing and turning on. Under these parameters, a Ti / Ti35 cyclic layer is prepared. Ti has good adhesion and is a soft metal layer, while Ti35 alloy is relatively hard. By setting the soft and hard alternation, the effect of bridging defects and preventing microcrack propagation is achieved.

[0025] The above-mentioned method for preparing an ultra-thick Zr / Ti / Ti35 corrosion-resistant coating for nuclear applications is characterized in that the deposition process in step 103 is as follows: simultaneously turning on the nuclear-grade Ti target and the nuclear-grade Ti35 target, gradually reducing the parameters of the nuclear-grade Ti target until it is extinguished, and gradually increasing the parameters of the nuclear-grade Ti35 target until it is saturated. Specifically, the nuclear-grade Ti target is initially set with a current of 150A~200A, a bias voltage of -140V, and a duty cycle of 20%. Every 5min~15min, the current is reduced by 10A, the bias voltage is reduced by -5V, and the duty cycle is increased by 5% until it is naturally extinguished. For the nuclear-grade Ti35 target, the initial arc source conditions are 80A, a bias voltage of -80V, and a duty cycle of 90%. Every 10min~20min, the current is increased by 5A until it reaches 150A~200A, the bias voltage is increased by -5V until it reaches -130V, and the duty cycle is decreased by 5% until it reaches 20%. In this invention, the deposition of the Ti layer and Ti35 layer in the first layer is controlled under these parameters. Unlike the traditional process, the Ti target is not directly extinguished and separated from the Ti35 layer. Instead, the two layers are organically fused and interlocked, which has a strong effect on the adhesion of the Ti layer and Ti35 layer.

[0026] The above-mentioned method for preparing an ultra-thick Zr / Ti / Ti35 corrosion-resistant coating for nuclear applications is characterized in that, in step four, the deposition of the Zr metal transition layer is carried out using multi-arc ion plating, and the deposition of the Ti / Ti35 corrosion-resistant functional layer is carried out using multi-arc ion plating, high-power pulsed magnetron sputtering, DC magnetron sputtering, radio frequency magnetron sputtering, or evaporation deposition. This invention uses Zr as the base layer, Ti as the transition layer or circulating layer, and Ti35 as the main layer. The method for depositing the Zr transition layer is mainly multi-arc ion plating technology, which includes: target types such as circular targets, rectangular targets, and columnar targets of various sizes, combined with DC or pulsed arc power supplies. Furthermore, the method for depositing the ultra-thick Zr / Ti / Ti35 corrosion-resistant functional layer includes, but is not limited to, multi-arc ion plating technology, and can also employ vacuum PVD coating technologies such as high-power pulsed magnetron sputtering, DC magnetron sputtering, radio frequency magnetron sputtering, and evaporation deposition. The processes used include circulating layers and gradient layers based on process and composition.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] 1. This invention is the first to materialize Ti35 alloy film. The thick Zr / Ti / Ti35 coating, prepared using multi-arc ion plating technology, exhibits a uniform and dense microstructure, aiming to effectively improve the corrosion resistance of the main body material of spent fuel reprocessing equipment. It has few overall penetration defects and provides excellent surface protection in corrosive media, demonstrating superior resistance to boiling nitric acid corrosion. While maintaining good performance, it significantly reduces the cost of the nuclear material body. This invention is not only applicable to nuclear chemical engineering but can also be extended to surface strengthening of engineering structural materials in civilian chemical fields such as corrosion-resistant tanks and pipelines.

[0029] 2. The Zr / Ti / Ti35 ultra-thick corrosion-resistant coating material prepared by the present invention uses Zr as the base layer (transition layer) and Ti as the composition gradient layer or modulation cycle layer. This not only alleviates the ion bombardment stress on the Ti35 main layer during the deposition process, but also enhances the compatibility and matching between the film layer and the substrate material at the interface.

[0030] 3. This invention is the first to use multi-arc ion plating technology to prepare Ti35 coatings. The coating thickness and structure can be controlled by adjusting the deposition parameters, and the operation is simple.

[0031] 4. The Zr / Ti / Ti35 ultra-thick corrosion-resistant coating material prepared by this invention has a uniform and dense structure, and has good coating properties for substrates with complex shapes. It can be used to prepare large-area film systems uniformly on an industrial scale.

[0032] 5. This invention is the first to deposit a thick Zr / Ti / Ti35 coating, which largely compensates for the penetration defects of the film, improves the corrosion resistance, and plays a good protective role for the equipment during long-term service in harsh environments.

[0033] 6. The Zr / Ti / Ti35 ultra-thick corrosion-resistant coating material prepared by this invention can not only meet the urgent needs of nuclear chemical industry, but also be applied to complex working conditions in civilian chemical industry where cost requirements are stringent, and has good economic efficiency and practicality.

[0034] 7. This invention proposes four methods for depositing Ti / Ti35 corrosion-resistant functional layers: ① Depositing a Ti35 layer on top of the original Zr layer and Ti substrate, but the Ti35 layer has a large gradient structure, either by lowering or increasing the parameters, resulting in two Ti35 gradient structures; ② Depositing a Ti35 process cycle layer on top of the original Zr layer and Ti substrate, continuously repeating the process by changing the bias voltage and duty cycle to form a process gradient layer; ③ Depositing a Ti / Ti35 composition cycle layer on top of the original Zr layer + Ti substrate; ④ Depositing a Ti + Ti35 composition gradient layer on top of the original Zr layer + Ti substrate, all in an on state, gradually decreasing the Ti power parameter and gradually increasing the high Ti35 power parameter to form a Ti-to-Ti35 gradient structure, applicable to the preparation of Ti / Ti35 corrosion-resistant functional layers under different conditions.

[0035] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0036] Figure 1 This is a SEM image of the Zr / Ti / Ti35 ultra-thick coating prepared in Example 1 of this invention.

[0037] Figure 2This is a SEM cross-sectional image of the Zr / Ti / Ti35 ultra-thick coating prepared in Example 1 of this invention. Detailed Implementation

[0038] Example 1

[0039] This embodiment includes the following steps:

[0040] Step 1: Nuclear-grade Zr, nuclear-grade Ti, and nuclear-grade Ti35 alloys are respectively prepared into high-density targets with a diameter of 120 mm by hot isostatic pressing. Fifteen sets of nuclear-grade Ti35 targets, three sets of nuclear-grade Zr targets, and five sets of nuclear-grade Ti targets are uniformly distributed and fixed on the target holder in the vacuum chamber of a multi-arc ion plating equipment. The mass purity of the nuclear-grade Zr, nuclear-grade Ti, and nuclear-grade Ti35 targets is not less than 99.9%.

[0041] Step 2: The surface of the TC4 substrate with the dissolver function is sandblasted. Then, the treated substrate is sequentially immersed in acetone, ethanol, and deionized water for ultrasonic cleaning for 20 minutes each. After being dried with cold air, a clean substrate is obtained. Using a specific fixture, the clean substrate is placed into the vacuum chamber from Step 1 and fixed on a two-dimensional rotating sample holder. The target-substrate distance is maintained at 150 mm. The vacuum chamber is then evacuated until the back-bottom vacuum level reaches 5.0 × 10⁻⁶ mm. -3 Pa, adjust the rotation speed of the rotating frame motor to 3r / min, heat the substrate to 300℃ in the vacuum chamber and bake it thoroughly for 2 hours;

[0042] Step 3: Introduce high-purity argon gas with a mass purity of not less than 99.99% into the vacuum chamber in Step 2 and maintain the vacuum degree at 0.5 Pa. Turn on the mechanical arc ignition to burn the nuclear-grade Zr target with an arc target current of 80 A. Apply a bias voltage of -600 V to the substrate with a duty cycle of 60% and bombard the substrate for 15 min to reduce the thickness of the substrate surface layer by 50 nm.

[0043] Step 4: Maintain an argon atmosphere of 0.5 Pa, ignite the nuclear-grade Zr target with an arc current of 80 A, adjust the bias voltage to -100 V, set the duty cycle to 40%, and deposit for 5 min to obtain a 300 nm thick Zr underlayer. Extinguish the nuclear-grade Zr targets one by one, and ignite the nuclear-grade Ti targets one by one with an arc current of 80 A, a bias voltage of -80 V, a duty cycle of 20%, and a deposition time of 2 min to obtain a 500 nm thick Ti transition layer. Extinguish the nuclear-grade Ti targets, and turn on all nuclear-grade Ti35 targets. Set the Ti35 arc source current to 150 A, decrease the bias voltage from -120 V to -80 V every 10 min by -3 V, and increase the duty cycle from 20% to 80% every 13 min by 2%. Deposit for a total of 7 h to obtain an ultra-thick Zr / Ti / Ti35 gradient coating of 25.9 μm.

[0044] Figure 1These are SEM surface morphology images of the Zr / Ti / Ti35 ultra-thick coating prepared in Example 1 of this invention. Figure 1 As can be seen, the Zr / Ti / Ti35 ultra-thick coating has a smooth and dense surface, with some large particles that are weakly adhered.

[0045] Figure 2 This is a SEM cross-sectional image of the Zr / Ti / Ti35 ultra-thick coating prepared in Example 1 of this invention. Figure 2 As can be seen, the process achieves a thickness of 25.9 μm, with a uniform and dense coating overall, no obvious internal defects, good bonding between the film and the substrate, and no film cracking, fully demonstrating the advantages of multi-arc ion plating technology.

[0046] Example 2

[0047] The difference between this embodiment and Embodiment 1 is that: the nuclear-grade Ti target is extinguished, the nuclear-grade Ti35 target is fully turned on, the Ti35 arc source current is set to 150A, the bias voltage is reduced from -140V to -80V every 50 minutes, the duty cycle is increased from 20% to 70% every 50 minutes, and the deposition time is 12 hours.

[0048] Testing revealed that the ultra-thick coating prepared in this embodiment had a smooth and dense surface, no obvious internal defects, good adhesion between the film and the substrate, and no cracking of the film substrate.

[0049] Example 3

[0050] The difference between this embodiment and Embodiment 1 is that: the nuclear-grade Ti target is extinguished, the nuclear-grade Ti35 target is fully turned on, the Ti35 arc source current is set to 150A, the bias voltage is reduced from -130V to -80V every 30 minutes, the duty cycle is increased from 20% to 60% every 10 minutes, and the deposition takes a total of 3 hours.

[0051] Testing revealed that the ultra-thick coating prepared in this embodiment had a smooth and dense surface, no obvious internal defects, good adhesion between the film and the substrate, and no cracking of the film substrate.

[0052] Example 4

[0053] This embodiment includes the following steps:

[0054] Step 1: Nuclear-grade Zr, nuclear-grade Ti, and nuclear-grade Ti35 alloys are respectively prepared into high-density targets with a diameter of 150 mm by hot isostatic pressing. Twenty sets of prepared nuclear-grade Ti35 targets, five sets of nuclear-grade Zr targets, and five sets of nuclear-grade Ti targets are uniformly distributed and fixed on the target holder in the vacuum chamber of a multi-arc ion plating equipment. The mass purity of the nuclear-grade Zr, nuclear-grade Ti, and nuclear-grade Ti35 targets is not less than 99.9%.

[0055] Step 2: The surface of the TC6 substrate with the dissolver function is sandblasted. Then, the treated substrate is sequentially immersed in acetone, ethanol, and deionized water for ultrasonic cleaning for 30 minutes each. After being dried with cold air, a clean substrate is obtained. Using a specific fixture, the clean substrate is placed into the vacuum chamber from Step 1 and fixed on a two-dimensional rotating sample holder, maintaining a target-substrate distance of 160 mm. The vacuum chamber is then evacuated until the back-bottom vacuum level reaches 9.0 × 10⁻⁶ mm. -4 Pa, adjust the rotation speed of the rotating frame motor to 2r / min, heat the substrate to 100℃ in the vacuum chamber and bake it thoroughly for 3 hours;

[0056] Step 3: Introduce high-purity argon gas with a mass purity of not less than 99.99% into the vacuum chamber in Step 2 and maintain the vacuum level at 1.5 Pa. Turn on the mechanical arc ignition to burn the nuclear-grade Zr target with an arc target current of 200 A. Apply a bias voltage of -700 V to the substrate with a duty cycle of 80% and bombard the substrate for 10 min to reduce the thickness of the substrate surface layer by 20 nm.

[0057] Step 4: Maintain an argon atmosphere of 1.5 Pa, ignite the nuclear-grade Zr target with an arc current of 100 A, adjust the bias voltage to -150 V, set the duty cycle to 50%, and deposit for 30 min to obtain a 2 μm thick Zr underlayer. Extinguish the nuclear-grade Zr targets one by one, and ignite the nuclear-grade Ti targets one by one with a current of 200 A, a bias voltage of -150 V, a duty cycle of 80%, and a deposition time of 30 min to obtain a 5 μm thick Ti transition layer. Extinguish the nuclear-grade Ti targets, and turn on all nuclear-grade Ti35 targets. Set the Ti35 arc source current to 150 A, increase the bias voltage from -80 V to -130 V every 30 min, and decrease the duty cycle from 80% to 20% every 50 min, and deposit for 7 h to obtain an ultra-thick Zr / Ti / Ti35 gradient coating of 26 μm.

[0058] Testing revealed that the ultra-thick coating prepared in this embodiment had a smooth and dense surface, no obvious internal defects, good adhesion between the film and the substrate, and no cracking of the film substrate.

[0059] Example 5

[0060] This embodiment includes the following steps:

[0061] Step 1: Nuclear-grade Zr, nuclear-grade Ti, and nuclear-grade Ti35 alloys are respectively prepared into high-density targets with a diameter of 160 mm by hot isostatic pressing. Ten sets of prepared nuclear-grade Ti35 targets, three sets of nuclear-grade Zr targets, and three sets of nuclear-grade Ti targets are uniformly distributed and fixed on the target holder in the vacuum chamber of a multi-arc ion plating equipment. The mass purity of the nuclear-grade Zr, nuclear-grade Ti, and nuclear-grade Ti35 targets is not less than 99.9%.

[0062] Step 2: The surface of the TA18 substrate for the dissolver function is sandblasted. Then, the treated substrate is sequentially immersed in acetone, ethanol, and deionized water for ultrasonic cleaning for 30 minutes each. After being dried with cold air, a clean substrate is obtained. Using a specific fixture, the clean substrate is placed into the vacuum chamber from Step 1 and fixed on a two-dimensional rotating sample holder. The target-substrate distance is maintained at 270 mm. The vacuum chamber is then evacuated until the back-bottom vacuum level reaches 7.0 × 10⁻⁶. -4 Pa, adjust the rotation speed of the rotating frame motor to 7r / min, heat the substrate to 350℃ in the vacuum chamber and bake it thoroughly for 1 hour;

[0063] Step 3: Introduce high-purity argon gas with a mass purity of not less than 99.99% into the vacuum chamber of Step 2 and maintain the vacuum degree at 3.0 Pa. Turn on the mechanical arc ignition to burn the nuclear-grade Zr target with an arc target current of 150 A. Apply a bias voltage of -800 V to the substrate with a duty cycle of 70% and bombard the substrate for 30 min to reduce the thickness of the substrate surface layer by 600 nm.

[0064] Step 4: Maintain an argon atmosphere of 3.0 Pa, ignite the nuclear-grade Zr target with an arc current of 150 A, adjust the bias voltage to -130 V, maintain a duty cycle of 60%, and deposit for 10 min to obtain an 800 nm thick Zr underlayer. Extinguish the nuclear-grade Zr targets one by one, and ignite the nuclear-grade Ti targets one by one with a current of 150 A, a bias voltage of -120 V, a duty cycle of 60%, and a deposition time of 15 min to obtain a 2 μm thick Ti transition layer. Extinguish the nuclear-grade Ti targets, and ignite all nuclear-grade Ti35 targets. Set the Ti35 arc source current to 150 A, increase the bias voltage from -80 V to -120 V every 10 min (-5 V to -120 V), and decrease the duty cycle from 80% to 20% every 34 min (3% to 20%). Deposit for 3 h to obtain an ultra-thick Zr / Ti / Ti35 gradient coating of 14 μm.

[0065] Testing revealed that the ultra-thick coating prepared in this embodiment had a smooth and dense surface, no obvious internal defects, good adhesion between the film and the substrate, and no cracking of the film substrate.

[0066] Example 6

[0067] The difference between this embodiment and embodiment 5 is as follows:

[0068] The nuclear-grade Ti target was turned off, and the nuclear-grade Ti35 target was fully turned on. The Ti35 arc source current was set to 150A, and the bias voltage was increased from -80V to -140V every 50 minutes. The duty cycle was decreased from 80% to 20% every 10 minutes. After deposition for 12 hours, an ultra-thick Zr / Ti / Ti35 gradient coating of 40μm was obtained.

[0069] Testing revealed that the ultra-thick coating prepared in this embodiment had a smooth and dense surface, no obvious internal defects, good adhesion between the film and the substrate, and no cracking of the film substrate.

[0070] Example 7

[0071] This embodiment includes the following steps:

[0072] Step 1: Nuclear-grade Zr, nuclear-grade Ti, and nuclear-grade Ti35 alloys are respectively prepared into high-density targets with a diameter of 100 mm by hot isostatic pressing. Fifteen sets of nuclear-grade Ti35 targets, three sets of nuclear-grade Zr targets, and five sets of nuclear-grade Ti targets are uniformly distributed and fixed on the target holder in the vacuum chamber of a multi-arc ion plating equipment. The mass purity of the nuclear-grade Zr, nuclear-grade Ti, and nuclear-grade Ti35 targets is not less than 99.9%.

[0073] Step 2: The surface of the nuclear-grade 316 stainless steel substrate for the dissolver function is sandblasted. Then, the treated substrate is sequentially immersed in acetone, ethanol, and deionized water for ultrasonic cleaning for 20 minutes each. After being dried with cold air, a clean substrate is obtained. Using a specific fixture, the clean substrate is placed into the vacuum chamber from Step 1 and fixed on a two-dimensional rotating sample holder, maintaining a target-substrate distance of 160 mm. The vacuum chamber is then evacuated until the back-bottom vacuum level reaches 9.0 × 10⁻⁶ mm. -4 Pa, adjust the rotation speed of the rotating frame motor to 2r / min, heat the substrate to 100℃ in the vacuum chamber and bake it thoroughly for 3 hours;

[0074] Step 3: Introduce high-purity argon gas with a mass purity of not less than 99.99% into the vacuum chamber in Step 2 and maintain the vacuum level at 1.5 Pa. Turn on the mechanical arc ignition to burn the nuclear-grade Zr target with an arc target current of 200 A. Apply a bias voltage of -700 V to the substrate with a duty cycle of 80% and bombard the substrate for 10 min to reduce the thickness of the substrate surface layer by 20 nm.

[0075] Step 4: Maintain an argon atmosphere of 0.5 Pa, ignite the nuclear-grade Zr target with an arc current of 80 A, adjust the bias voltage to -100 V, set the duty cycle to 40%, and deposit for 5 min to obtain a 300 nm thick Zr underlayer. Extinguish the nuclear-grade Zr targets one by one, and ignite the nuclear-grade Ti targets one by one with an arc current of 80 A, a bias voltage of -80 V, a duty cycle of 20%, and a deposition time of 2 min to obtain a 500 nm thick Ti transition layer. Extinguish the nuclear-grade Ti targets, set the arc current of the nuclear-grade Ti35 target to 150 A, and increase the bias voltage from -80 V to -140 V every 3 min by -4 V to -80 V, and then decrease it every 3 min by -4 V to -80 V. Correspondingly, adjust the duty cycle from 80% to 20% every 3 min by decreasing it by 4% to 80%, and then increase it every 3 min by increasing it by 4% to 80%. Repeat this cycle 5 times, with each cycle lasting 90 min, for a total deposition time of 7.5 h, to obtain an ultra-thick Zr / Ti / Ti35 cyclic gradient coating of 28 μm thickness.

[0076] Testing revealed that the ultra-thick coating prepared in this embodiment had a smooth and dense surface, no obvious internal defects, good adhesion between the film and the substrate, and no cracking of the film substrate.

[0077] Example 8

[0078] This embodiment includes the following steps:

[0079] Step 1: Nuclear-grade Zr, nuclear-grade Ti, and nuclear-grade Ti35 alloys are respectively prepared into high-density targets with a diameter of 150 mm by hot isostatic pressing. The prepared four sets of nuclear-grade Ti35 targets, two sets of nuclear-grade Zr targets, and two sets of nuclear-grade Ti targets are uniformly distributed and fixed on the target holder in the vacuum chamber of the multi-arc ion plating equipment. The mass purity of the nuclear-grade Zr target, nuclear-grade Ti target, and nuclear-grade Ti35 target is not less than 99.9%.

[0080] Step 2: The surface of the T9 ironclad steel substrate for the dissolver function is sandblasted. Then, the treated substrate is sequentially immersed in acetone, ethanol, and deionized water for ultrasonic cleaning for 30 minutes each. After being dried with cold air, a clean substrate is obtained. Using a specific fixture, the clean substrate is placed into the vacuum chamber from Step 1 and fixed on a two-dimensional rotating sample holder, maintaining a target-substrate distance of 150 mm. The vacuum chamber is then evacuated until the back-bottom vacuum level reaches 5.0 × 10⁻⁶ mm. -3 Pa, adjust the rotation speed of the rotating frame motor to 3r / min, heat the substrate to 300℃ in the vacuum chamber and bake it thoroughly for 2 hours;

[0081] Step 3: Introduce high-purity argon gas with a mass purity of not less than 99.99% into the vacuum chamber in Step 2 and maintain the vacuum degree at 0.5 Pa. Turn on the mechanical arc ignition to burn the nuclear-grade Zr target with an arc target current of 80 A. Apply a bias voltage of -600 V to the substrate with a duty cycle of 60% and bombard the substrate for 15 min to reduce the thickness of the substrate surface layer by 50 nm.

[0082] Step 4: Maintain an argon atmosphere of 1.5 Pa, ignite the nuclear-grade Zr target with an arc at 100 A, adjust the bias voltage to -150 V, maintain a duty cycle of 50%, and deposit for 30 min to obtain a 2 μm thick Zr underlayer. Extinguish the nuclear-grade Zr targets one by one, and ignite the nuclear-grade Ti targets one by one with a current of 200 A, a bias voltage of -150 V, a duty cycle of 80%, and a deposition time of 30 min to obtain a 5 μm thick Ti transition layer. Extinguish the nuclear-grade Ti targets and apply the nuclear-grade Ti... The arc current of the target material was set to 200A. The bias voltage was increased from -80V to -140V every 5 minutes by increasing by -2V to -80V every 5 minutes. Correspondingly, the duty cycle was adjusted from 80% to 20% every 5 minutes by decreasing by 2% to 80% every 5 minutes. This cycle was repeated once, with each cycle lasting 300 minutes. The deposition was carried out for a total of 5 hours, resulting in an ultra-thick Zr / Ti / Ti35 cyclic gradient coating with a thickness of 15μm.

[0083] Testing revealed that the ultra-thick coating prepared in this embodiment had a smooth and dense surface, no obvious internal defects, good adhesion between the film and the substrate, and no cracking of the film substrate.

[0084] Example 9

[0085] This embodiment includes the following steps:

[0086] Step 1: Nuclear-grade Zr, nuclear-grade Ti, and nuclear-grade Ti35 alloys are respectively prepared into high-density targets with a diameter of 160 mm by hot isostatic pressing. Ten sets of prepared nuclear-grade Ti35 targets, three sets of nuclear-grade Zr targets, and three sets of nuclear-grade Ti targets are uniformly distributed and fixed on the target holder in the vacuum chamber of a multi-arc ion plating equipment. The mass purity of the nuclear-grade Zr, nuclear-grade Ti, and nuclear-grade Ti35 targets is not less than 99.9%.

[0087] Step 2: The surface of the nuclear-grade 304 stainless steel substrate for the dissolver function is sandblasted. Then, the treated substrate is sequentially immersed in acetone, ethanol, and deionized water for ultrasonic cleaning for 30 minutes each. After being dried with cold air, a clean substrate is obtained. Using a specific fixture, the clean substrate is placed into the vacuum chamber from Step 1 and fixed on a two-dimensional rotating sample holder, maintaining a target-substrate distance of 270 mm. The vacuum chamber is then evacuated until the back-bottom vacuum level reaches 7.0 × 10⁻⁶. -4 Pa, adjust the rotation speed of the rotating frame motor to 7r / min, heat the substrate to 350℃ in the vacuum chamber and bake it thoroughly for 1 hour;

[0088] Step 3: Introduce high-purity argon gas with a mass purity of not less than 99.99% into the vacuum chamber of Step 2 and maintain the vacuum degree at 3.0 Pa. Turn on the mechanical arc ignition to burn the nuclear-grade Zr target with an arc target current of 150 A. Apply a bias voltage of -800 V to the substrate with a duty cycle of 70% and bombard the substrate for 30 min to reduce the thickness of the substrate surface layer by 600 nm.

[0089] Step 4: Maintain an argon atmosphere of 3.0 Pa, ignite the nuclear-grade Zr target with an arc at 150 A, adjust the bias voltage to -130 V, maintain a duty cycle of 60%, and deposit for 10 min to obtain an 800 nm thick Zr underlayer. Then, extinguish the nuclear-grade Zr targets one by one and ignite the nuclear-grade Ti targets one by one with an arc at 150 A, a bias voltage of -120 V, a duty cycle of 60%, and a deposition time of 15 min to obtain a 2 μm thick Ti transition layer. Finally, extinguish the nuclear-grade Ti targets and apply the nuclear-grade Ti... The arc current of the target material was set to 180A. The bias voltage was increased from -80V to -140V every 4 minutes by increasing the bias voltage from -5V to -80V every 4 minutes. Correspondingly, the duty cycle was adjusted from 80% to 20% by decreasing the duty cycle from 80% to 20% every 4 minutes by decreasing the duty cycle from 80% to 80% every 4 minutes by increasing the duty cycle from 80% to 20% every 4 minutes. This cycle was repeated twice, with each cycle lasting 96 minutes. The total deposition time was 192 minutes, resulting in an ultra-thick Zr / Ti / Ti35 cyclic gradient coating with a thickness of 12μm.

[0090] Testing revealed that the ultra-thick coating prepared in this embodiment had a smooth and dense surface, no obvious internal defects, good adhesion between the film and the substrate, and no cracking of the film substrate.

[0091] Example 10

[0092] This embodiment includes the following steps:

[0093] Step 1: Nuclear-grade Zr, nuclear-grade Ti, and nuclear-grade Ti35 alloys are respectively prepared into high-density targets with a diameter of 100 mm by hot isostatic pressing. Fifteen sets of nuclear-grade Ti35 targets, three sets of nuclear-grade Zr targets, and five sets of nuclear-grade Ti targets are uniformly distributed and fixed on the target holder in the vacuum chamber of a multi-arc ion plating equipment. The mass purity of the nuclear-grade Zr, nuclear-grade Ti, and nuclear-grade Ti35 targets is not less than 99.9%.

[0094] Step 2: The surface of the nuclear-grade 316 stainless steel substrate for the dissolver function is sandblasted. Then, the treated substrate is sequentially immersed in acetone, ethanol, and deionized water for ultrasonic cleaning for 30 minutes each. After being dried with cold air, a clean substrate is obtained. Using a specific fixture, the clean substrate is placed into the vacuum chamber from Step 1 and fixed on a two-dimensional rotating sample holder, maintaining a target-substrate distance of 270 mm. The vacuum chamber is then evacuated until the back-bottom vacuum level reaches 7.0 × 10⁻⁶ mm. -4 Pa, adjust the rotation speed of the rotating frame motor to 7r / min, heat the substrate to 350℃ in the vacuum chamber and bake it thoroughly for 1 hour;

[0095] Step 3: Introduce high-purity argon gas with a mass purity of not less than 99.99% into the vacuum chamber of Step 2 and maintain the vacuum degree at 3.0 Pa. Turn on the mechanical arc ignition to burn the nuclear-grade Zr target with an arc target current of 150 A. Apply a bias voltage of -800 V to the substrate with a duty cycle of 70% and bombard the substrate for 30 min to reduce the thickness of the substrate surface layer by 600 nm.

[0096] Step 4: Maintain an argon atmosphere of 0.5 Pa, ignite the nuclear-grade Zr target with an arc current of 80 A, adjust the bias voltage to -100 V, and set the duty cycle to 40%. Deposit for 5 minutes to obtain a 300 nm thick Zr underlayer. Extinguish the nuclear-grade Zr targets one by one, and ignite the nuclear-grade Ti targets one by one with an arc current of 80 A, a bias voltage of -80 V, and a duty cycle of 20%. Deposit for 2 minutes to obtain a 500 nm thick Ti transition layer. Extinguish the nuclear-grade Ti targets and ignite the nuclear-grade Ti35 targets. The arc current was set to 120A, the bias voltage to -80V, and the duty cycle to 90% to deposit a Ti35 coating for 5 minutes. Then, the nuclear-grade Ti35 target was turned off, the nuclear-grade Ti target was turned on, and the Ti coating was deposited for 2 minutes with an arc current of 120A, a bias voltage to -80V, and a duty cycle of 90%. The above process was repeated 100 times, for a total deposition time of 700 minutes, to obtain an ultra-thick Zr / Ti / Ti35 composition cycle coating (Zr-Ti-Ti35 / Ti) with a thickness of 41μm.

[0097] Testing revealed that the ultra-thick coating prepared in this embodiment had a smooth and dense surface, no obvious internal defects, good adhesion between the film and the substrate, and no cracking of the film substrate.

[0098] Example 11

[0099] This embodiment includes the following steps:

[0100] Step 1: Nuclear-grade Zr, nuclear-grade Ti, and nuclear-grade Ti35 alloys are respectively prepared into high-density targets with a diameter of 150 mm by hot isostatic pressing. The prepared four sets of nuclear-grade Ti35 targets, two sets of nuclear-grade Zr targets, and two sets of nuclear-grade Ti targets are uniformly distributed and fixed on the target holder in the vacuum chamber of the multi-arc ion plating equipment. The mass purity of the nuclear-grade Zr target, nuclear-grade Ti target, and nuclear-grade Ti35 target is not less than 99.9%.

[0101] Step 2: The surface of the T9 ironclad steel substrate for the dissolver function is sandblasted. Then, the treated substrate is sequentially immersed in acetone, ethanol, and deionized water for ultrasonic cleaning for 30 minutes each. After being dried with cold air, a clean substrate is obtained. Using a specific fixture, the clean substrate is placed into the vacuum chamber from Step 1 and fixed on a two-dimensional rotating sample holder, maintaining a target-substrate distance of 160 mm. The vacuum chamber is then evacuated until the back-bottom vacuum level reaches 9.0 × 10⁻⁶ mm. -4Pa, adjust the rotation speed of the rotating frame motor to 2r / min, heat the substrate to 100℃ in the vacuum chamber and bake it thoroughly for 3 hours;

[0102] Step 3: Introduce high-purity argon gas with a mass purity of not less than 99.99% into the vacuum chamber in Step 2 and maintain the vacuum level at 1.5 Pa. Turn on the mechanical arc ignition to burn the nuclear-grade Zr target with an arc target current of 200 A. Apply a bias voltage of -700 V to the substrate with a duty cycle of 80% and bombard the substrate for 10 min to reduce the thickness of the substrate surface layer by 20 nm.

[0103] Step 4: Maintain an argon atmosphere of 1.5 Pa, ignite the nuclear-grade Zr target with an arc at 100 A, adjust the bias voltage to -150 V, maintain a duty cycle of 50%, and deposit for 30 min to obtain a 2 μm thick Zr underlayer. Then, extinguish the nuclear-grade Zr targets one by one and ignite the nuclear-grade Ti targets one by one with an arc at 200 A, a bias voltage of -150 V, a duty cycle of 80%, and a deposition time of 30 min to obtain a 5 μm thick Ti transition layer. Finally, extinguish the nuclear-grade Ti targets and ignite the nuclear-grade Ti35 targets. The arc current was set to 200A, the bias voltage to -140V, and the duty cycle to 20%, and a Ti35 coating was deposited for 15 minutes. Then, the nuclear-grade Ti35 target was turned off, the nuclear-grade Ti target was turned on, and a Ti coating was deposited for 10 minutes with an arc current of 200A, a bias voltage to -140V, and a duty cycle of 20%. The above process was repeated 5 times, for a total deposition time of 125 minutes, to obtain an ultra-thick Zr / Ti / Ti35 composition cycle coating (Zr-Ti-Ti35 / Ti) with a thickness of 15μm.

[0104] Testing revealed that the ultra-thick coating prepared in this embodiment had a smooth and dense surface, no obvious internal defects, good adhesion between the film and the substrate, and no cracking of the film substrate.

[0105] Example 12

[0106] This embodiment includes the following steps:

[0107] Step 1: Nuclear-grade Zr, nuclear-grade Ti, and nuclear-grade Ti35 alloys are respectively prepared into high-density targets with a diameter of 160 mm by hot isostatic pressing. Ten sets of prepared nuclear-grade Ti35 targets, three sets of nuclear-grade Zr targets, and three sets of nuclear-grade Ti targets are uniformly distributed and fixed on the target holder in the vacuum chamber of a multi-arc ion plating equipment. The mass purity of the nuclear-grade Zr, nuclear-grade Ti, and nuclear-grade Ti35 targets is not less than 99.9%.

[0108] Step 2: The surface of the nuclear-grade 304 stainless steel substrate for the dissolver function is sandblasted. Then, the treated substrate is sequentially immersed in acetone, ethanol, and deionized water for ultrasonic cleaning for 20 minutes each. After being dried with cold air, a clean substrate is obtained. Using a specific fixture, the clean substrate is placed into the vacuum chamber from Step 1 and fixed on a two-dimensional rotating sample holder, maintaining a target-substrate distance of 150 mm. The vacuum chamber is then evacuated until the back-bottom vacuum level reaches 5.0 × 10⁻⁶. -3 Pa, adjust the rotation speed of the rotating frame motor to 3r / min, heat the substrate to 300℃ in the vacuum chamber and bake it thoroughly for 2 hours;

[0109] Step 3: Introduce high-purity argon gas with a mass purity of not less than 99.99% into the vacuum chamber in Step 2 and maintain the vacuum degree at 0.5 Pa. Turn on the mechanical arc ignition to burn the nuclear-grade Zr target with an arc target current of 80 A. Apply a bias voltage of -600 V to the substrate with a duty cycle of 60% and bombard the substrate for 15 min to reduce the thickness of the substrate surface layer by 50 nm.

[0110] Step 4: Maintain an argon atmosphere of 3.0 Pa, ignite the nuclear-grade Zr target with an arc at 150 A, adjust the bias voltage to -130 V, maintain a duty cycle of 60%, and deposit for 10 min to obtain an 800 nm thick Zr underlayer. Then, extinguish the nuclear-grade Zr targets one by one and ignite the nuclear-grade Ti targets one by one with an arc at 150 A, a bias voltage of -120 V, a duty cycle of 60%, and a deposition time of 15 min to obtain a 2 μm thick Ti transition layer. Finally, extinguish the nuclear-grade Ti targets and activate the nuclear-grade Ti35 target. The target was set with an arc current of 170A, a bias voltage of -100V, and a duty cycle of 60% to deposit a Ti35 coating for 10 minutes. Then, the nuclear-grade Ti35 target was turned off, and the nuclear-grade Ti target was turned on. The Ti coating was deposited for 3 minutes with an arc current of 170A, a bias voltage of -100V, and a duty cycle of 60%. The above process was repeated 20 times, for a total deposition time of 260 minutes, to obtain an ultra-thick Zr / Ti / Ti35 composition cycle coating (Zr-Ti-Ti35 / Ti) with a thickness of 16μm.

[0111] Testing revealed that the ultra-thick coating prepared in this embodiment had a smooth and dense surface, no obvious internal defects, good adhesion between the film and the substrate, and no cracking of the film substrate.

[0112] Example 13

[0113] This embodiment includes the following steps:

[0114] Step 1: Nuclear-grade Zr, nuclear-grade Ti, and nuclear-grade Ti35 alloys are respectively prepared into high-density targets with a diameter of 100 mm by hot isostatic pressing. Fifteen sets of nuclear-grade Ti35 targets, three sets of nuclear-grade Zr targets, and five sets of nuclear-grade Ti targets are uniformly distributed and fixed on the target holder in the vacuum chamber of a multi-arc ion plating equipment. The mass purity of the nuclear-grade Zr, nuclear-grade Ti, and nuclear-grade Ti35 targets is not less than 99.9%.

[0115] Step 2: The surface of the nuclear-grade 316 stainless steel substrate for the dissolver function is sandblasted. Then, the treated substrate is sequentially immersed in acetone, ethanol, and deionized water for ultrasonic cleaning for 30 minutes each. After being dried with cold air, a clean substrate is obtained. Using a specific fixture, the clean substrate is placed into the vacuum chamber from Step 1 and fixed on a two-dimensional rotating sample holder, maintaining a target-substrate distance of 270 mm. The vacuum chamber is then evacuated until the back-bottom vacuum level reaches 7.0 × 10⁻⁶ mm. -4 Pa, adjust the rotation speed of the rotating frame motor to 7r / min, heat the substrate to 350℃ in the vacuum chamber and bake it thoroughly for 1 hour;

[0116] Step 3: Introduce high-purity argon gas with a mass purity of not less than 99.99% into the vacuum chamber of Step 2 and maintain the vacuum degree at 3.0 Pa. Turn on the mechanical arc ignition to burn the nuclear-grade Zr target with an arc target current of 150 A. Apply a bias voltage of -800 V to the substrate with a duty cycle of 70% and bombard the substrate for 30 min to reduce the thickness of the substrate surface layer by 600 nm.

[0117] Step 4: Maintain an argon atmosphere of 0.5 Pa, ignite the nuclear-grade Zr target with an arc at 80 A, adjust the bias voltage to -100 V, and set the duty cycle to 40%. The deposition time is 5 min, resulting in a 300 nm thick Zr underlayer. Extinguish the nuclear-grade Zr targets one by one, and ignite the nuclear-grade Ti targets one by one with an arc at 80 A, a bias voltage of -80 V, and a duty cycle of 20%. The deposition time is 2 min, resulting in a 500 nm thick Ti transition layer. Simultaneously turn on the nuclear-grade Ti target and the nuclear-grade Ti35 target. Gradually decrease the parameters of the nuclear-grade Ti target until it is extinguished, and gradually increase the parameters of the high-grade Ti35 target until saturation. Specifically, the nuclear-grade... The initial settings for the Ti target were: current 150A, bias voltage -140V, duty cycle 20%. Every 5 minutes, the current was reduced by 10A, the bias voltage was reduced by -5V, and the duty cycle was increased by 5% until natural extinction. For the nuclear-grade Ti35 target, the initial arc source conditions were 80A, bias voltage -80V, and duty cycle 90%. Every 10 minutes, the current was increased by 5A to 150A, the bias voltage was increased by -5V to -130V, and the duty cycle was decreased by 5% to 20%. After stabilization, deposition was carried out for a total of 3 hours to obtain an ultra-thick Zr / Ti / Ti35 compositional cycling coating (Zr-Ti-TiTi35) with a thickness of 13μm.

[0118] Testing revealed that the ultra-thick coating prepared in this embodiment had a smooth and dense surface, no obvious internal defects, good adhesion between the film and the substrate, and no cracking of the film substrate.

[0119] Example 14

[0120] This embodiment includes the following steps:

[0121] Step 1: Nuclear-grade Zr, nuclear-grade Ti, and nuclear-grade Ti35 alloys are respectively prepared into high-density targets with a diameter of 150 mm by hot isostatic pressing. The prepared four sets of nuclear-grade Ti35 targets, two sets of nuclear-grade Zr targets, and two sets of nuclear-grade Ti targets are uniformly distributed and fixed on the target holder in the vacuum chamber of the multi-arc ion plating equipment. The mass purity of the nuclear-grade Zr target, nuclear-grade Ti target, and nuclear-grade Ti35 target is not less than 99.9%.

[0122] Step 2: The surface of the T9 ironclad steel substrate for the dissolver function is sandblasted. Then, the treated substrate is sequentially immersed in acetone, ethanol, and deionized water for ultrasonic cleaning for 20 minutes each. After being dried with cold air, a clean substrate is obtained. Using a specific fixture, the clean substrate is placed into the vacuum chamber from Step 1 and fixed on a two-dimensional rotating sample holder, maintaining a target-substrate distance of 150 mm. The vacuum chamber is then evacuated until the back-bottom vacuum level reaches 5.0 × 10⁻⁶ mm. -3 Pa, adjust the rotation speed of the rotating frame motor to 3r / min, heat the substrate to 300℃ in the vacuum chamber and bake it thoroughly for 2 hours;

[0123] Step 3: Introduce high-purity argon gas with a mass purity of not less than 99.99% into the vacuum chamber in Step 2 and maintain the vacuum degree at 0.5 Pa. Turn on the mechanical arc ignition to burn the nuclear-grade Zr target with an arc target current of 80 A. Apply a bias voltage of -600 V to the substrate with a duty cycle of 60% and bombard the substrate for 15 min to reduce the thickness of the substrate surface layer by 50 nm.

[0124] Step 4: Maintain an argon atmosphere of 1.5 Pa, ignite the nuclear-grade Zr target with an arc at 100 A, adjust the bias voltage to -150 V, and set the duty cycle to 50%. Deposition time is 30 min to obtain a 2 μm thick Zr underlayer. Extinguish the nuclear-grade Zr targets one by one, and ignite the nuclear-grade Ti targets one by one with a current of 200 A, a bias voltage of -150 V, and a duty cycle of 80%. Deposition time is 30 min to obtain a 5 μm thick Ti transition layer. Simultaneously turn on the nuclear-grade Ti target and the nuclear-grade Ti35 target, gradually decreasing the parameters of the nuclear-grade Ti target until it is extinguished, and gradually increasing the parameters of the high-grade Ti35 target until saturation. Specifically, the nuclear-grade... The initial settings for the Ti target were: current 200A, bias voltage -140V, duty cycle 20%. Every 15 minutes, the current was reduced by 10A, the bias voltage was reduced by -5V, and the duty cycle was increased by 5% until natural extinction. For the nuclear-grade Ti35 target, the initial arc source conditions were 80A, bias voltage -80V, and duty cycle 90%. Every 20 minutes, the current was increased by 5A to 200A, the bias voltage was increased by -5V to -130V, and the duty cycle was decreased by 5% to 20%. After stabilization, a total deposition time of 5 hours was obtained to obtain an ultra-thick Zr / Ti / Ti35 compositional cycling coating (Zr-Ti-TiTi35) with a thickness of 16μm.

[0125] Testing revealed that the ultra-thick coating prepared in this embodiment had a smooth and dense surface, no obvious internal defects, good adhesion between the film and the substrate, and no cracking of the film substrate.

[0126] Example 15

[0127] This embodiment includes the following steps:

[0128] Step 1: Nuclear-grade Zr, nuclear-grade Ti, and nuclear-grade Ti35 alloys are respectively prepared into high-density targets with a diameter of 160 mm by hot isostatic pressing. Ten sets of prepared nuclear-grade Ti35 targets, three sets of nuclear-grade Zr targets, and three sets of nuclear-grade Ti targets are uniformly distributed and fixed on the target holder in the vacuum chamber of a multi-arc ion plating equipment. The mass purity of the nuclear-grade Zr, nuclear-grade Ti, and nuclear-grade Ti35 targets is not less than 99.9%.

[0129] Step 2: The surface of the nuclear-grade 304 stainless steel substrate for the dissolver function is sandblasted. Then, the treated substrate is sequentially immersed in acetone, ethanol, and deionized water for ultrasonic cleaning for 30 minutes each. After being dried with cold air, a clean substrate is obtained. Using a specific fixture, the clean substrate is placed into the vacuum chamber from Step 1 and fixed on a two-dimensional rotating sample holder, maintaining a target-substrate distance of 160 mm. The vacuum chamber is then evacuated until the back-bottom vacuum level reaches 9.0 × 10⁻⁶ mm. -4 Pa, adjust the rotation speed of the rotating frame motor to 2r / min, heat the substrate to 100℃ in the vacuum chamber and bake it thoroughly for 3 hours;

[0130] Step 3: Introduce high-purity argon gas with a mass purity of not less than 99.99% into the vacuum chamber in Step 2 and maintain the vacuum level at 1.5 Pa. Turn on the mechanical arc ignition to burn the nuclear-grade Zr target with an arc target current of 200 A. Apply a bias voltage of -700 V to the substrate with a duty cycle of 80% and bombard the substrate for 10 min to reduce the thickness of the substrate surface layer by 20 nm.

[0131] Step 4: Maintain an argon atmosphere of 3.0 Pa, ignite the nuclear-grade Zr target with an arc at 150 A, adjust the bias voltage to -130 V, and set the duty cycle to 60%. The deposition time is 10 min, resulting in an 800 nm thick Zr underlayer. Then, extinguish the nuclear-grade Zr targets one by one and ignite the nuclear-grade Ti targets one by one with an arc at 150 A, a bias voltage of -120 V, and a duty cycle of 60%. The deposition time is 15 min, resulting in a 2 μm thick Ti transition layer. Simultaneously, turn on both the nuclear-grade Ti and nuclear-grade Ti35 targets. Gradually decrease the parameters of the nuclear-grade Ti target until it is extinguished, and gradually increase the parameters of the high-grade Ti35 target until saturation. Specifically, the nuclear-grade Ti target parameters are... The initial settings for the Ti-grade target were: current 180A, bias voltage -140V, and duty cycle 20%. Every 10 minutes, the current was reduced by 10A, the bias voltage was reduced by -5V, and the duty cycle was increased by 5% until it naturally extinguished. For the nuclear-grade Ti35 target, the initial arc source conditions were 80A, bias voltage -80V, and duty cycle 90%. Every 15 minutes, the current was increased by 5A to 180A, the bias voltage was increased by -5V to -130V, and the duty cycle was decreased by 5% to 20%. After stabilization, a total deposition time of 6 hours was obtained to obtain an ultra-thick Zr / Ti / Ti35 compositional cycling coating (Zr-Ti-TiTi35) with a thickness of 20μm.

[0132] Testing revealed that the ultra-thick coating prepared in this embodiment had a smooth and dense surface, no obvious internal defects, good adhesion between the film and the substrate, and no cracking of the film substrate.

[0133] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing an ultra-thick Zr / Ti / Ti35 corrosion-resistant coating for nuclear applications, characterized in that, Includes the following steps: Step 1: Install nuclear-grade Zr target, nuclear-grade Ti target, and nuclear-grade Ti35 target into the coating machine to obtain a coating machine containing the targets; Step 2: The substrate is sandblasted, ultrasonically cleaned and dried in sequence. Then, it is loaded into the coating machine containing the target material obtained in Step 1 through tooling fixtures to pre-treat the substrate, thus obtaining a coating machine containing the pre-treated substrate. Step 3: After vacuuming the coating machine containing the pretreated substrate obtained in Step 2, the pretreated substrate is cleaned to obtain a clean substrate; the cleaning is high bias bombardment cleaning or IET etching cleaning. Step 4: Sequentially deposit a Zr metal transition layer and a Ti / Ti35 corrosion-resistant functional layer on the clean substrate obtained in Step 3 to obtain an ultra-thick Zr / Ti / Ti35 corrosion-resistant coating on the surface of the clean substrate. The process of depositing the Zr metal transition layer and the Ti / Ti35 corrosion-resistant functional layer is as follows: Step 101: High-purity argon gas is introduced into the vacuum chamber of the coating machine and the vacuum degree is maintained at 0.5Pa~3Pa. The nuclear-grade Zr target material is ignited by mechanical arc ignition or high-frequency high-voltage arc ignition, the current is 80A~150A, the bias voltage is adjusted to -100V~-150V, the duty cycle is 40%~60%, and the deposition time is 5min~30min to obtain a Zr metal transition layer with a thickness of 300nm~2μm. Step 102: Extinguish the nuclear-grade Zr targets one by one and turn on the corresponding nuclear-grade Ti targets one by one, while maintaining an arc current of 80A~200A, a bias voltage of -80V~-150V, a duty cycle of 20%~80%, and a deposition time of 2min~30min to obtain a Ti layer with a thickness of 500nm~5μm. Step 103: Adjust the parameters of the nuclear-grade Ti target and the nuclear-grade Ti35 target, and deposit for a total of 3h~12h to obtain an ultra-thick Zr / Ti / Ti35 coating with a thickness of 10μm~40μm.

2. The method for preparing an ultra-thick Zr / Ti / Ti35 corrosion-resistant coating for nuclear applications according to claim 1, characterized in that, The nuclear-grade Zr target, nuclear-grade Ti target, and nuclear-grade Ti35 target mentioned in step one are all high-density targets prepared by hot isostatic pressing or spraying. The coating machine containing the targets is equipped with 4 to 20 sets of nuclear-grade Ti35 targets, 2 to 5 sets of nuclear-grade Zr targets, and 2 to 10 sets of nuclear-grade Ti targets. The mass purity of the nuclear-grade Zr target, nuclear-grade Ti target, and nuclear-grade Ti35 target is not less than 99.9%.

3. The method for preparing an ultra-thick Zr / Ti / Ti35 corrosion-resistant coating for nuclear applications according to claim 1, characterized in that, The substrate mentioned in step two is nuclear-grade stainless steel, nuclear-grade titanium alloy, or nuclear-grade zirconium alloy. The substrate is fixed on a two-dimensional or three-dimensional rotating sample holder in the vacuum chamber of the coating machine. The pretreatment process is as follows: maintaining a target-substrate distance of 150mm~270mm, and evacuating the vacuum chamber of the coating machine to a back-bottom vacuum degree of 7.0×10⁻⁶. -4 Pa ~ 5.0 × 10 -3 Pa, adjust the motor speed of the sample holder to 2r / min~7r / min, heat to 100℃~350℃ in the vacuum chamber and keep warm for 1h~3h.

4. The method for preparing an ultra-thick Zr / Ti / Ti35 corrosion-resistant coating for nuclear applications according to claim 1, characterized in that, The high-bias bombardment cleaning or IET etching cleaning process described in step three is as follows: high-purity argon gas is introduced into the vacuum chamber of the coating machine and the vacuum degree is maintained at 0.5Pa~3Pa. High-frequency high-voltage arc ignition or mechanical arc ignition is used to ignite the nuclear-grade Zr target material with an arc target current of 80A~200A. A bias voltage of -600V~-800V is applied to the substrate with a duty cycle of 60%~80%. The cleaning time is 10min~30min, reducing the surface layer thickness of the substrate by 20nm~600nm. The mass purity of the argon gas is not less than 99.99%.

5. The method for preparing an ultra-thick Zr / Ti / Ti35 corrosion-resistant coating for nuclear applications according to claim 1, characterized in that, The deposition process described in step 103 is as follows: extinguish the nuclear-grade Ti target, turn on the nuclear-grade Ti35 target to deposit a Ti35 gradient layer, decrease the bias voltage from -120V to -140V every 10min to 50min by -3V to -5V until -80V, or in the opposite direction increase the bias voltage from -80V every 10min to 50min by -3V to -5V until -120V to -140V, increase the duty cycle from 20% to 2% to 5% every 10min to 50min until 60% to 80%, or in the opposite direction decrease the duty cycle from 60% to 80% by 2% to 5% every 10min to 50min until 20%.

6. The method for preparing an ultra-thick Zr / Ti / Ti35 corrosion-resistant coating for nuclear applications according to claim 1, characterized in that, The deposition process described in step 103 is as follows: extinguish the nuclear-grade Ti target, set the arc current of the nuclear-grade Ti35 target to 150A~200A, and cycle the bias voltage from -80V to -140V and the duty cycle from 20% to 80% 1 to 5 times. Each cycle involves increasing the bias voltage from -2V to -5V every 3 to 5 minutes until it reaches -140V, then decreasing it from -2V to -5V every 3 to 5 minutes until it reaches -80V. The duty cycle is also increased from 20% to 2% to 5% every 3 to 5 minutes until it reaches 60 to 80%, then decreasing it from 2% to 5% every 3 to 5 minutes until it reaches 20%. The cycle period for each cycle is 90 to 300 minutes.

7. The method for preparing an ultra-thick Zr / Ti / Ti35 corrosion-resistant coating for nuclear applications according to claim 1, characterized in that, The deposition process described in step 103 is as follows: extinguish the nuclear-grade Ti target, turn on the nuclear-grade Ti35 target and deposit the Ti35 coating for 5 min to 15 min with an arc current of 120 A to 200 A, a bias voltage of -80 to -140 V, and a duty cycle of 20% to 90%. Then turn off the nuclear-grade Ti35 target, turn on the nuclear-grade Ti target, and deposit the Ti layer for 2 min to 10 min with an arc current of 120 A to 200 A, a bias voltage of -80 to -140 V, and a duty cycle of 20% to 90%. Repeat the above process 5 to 100 times.

8. The method for preparing an ultra-thick Zr / Ti / Ti35 corrosion-resistant coating for nuclear applications according to claim 1, characterized in that, The deposition process described in step 103 is as follows: simultaneously turn on the nuclear-grade Ti target and the nuclear-grade Ti35 target, gradually reduce the parameters of the nuclear-grade Ti target until it is extinguished, and gradually increase the parameters of the nuclear-grade Ti35 target until it is saturated. Specifically, the nuclear-grade Ti target is initially set to a current of 150A~200A, a bias voltage of -140V, and a duty cycle of 20%. Every 5min~15min, the current is reduced by 10A, the bias voltage is reduced by -5V, and the duty cycle is increased by 5% until it is naturally extinguished. For the nuclear-grade Ti35 target, the initial arc source conditions are 80A, a bias voltage of -80V, and a duty cycle of 90%. Every 10min~20min, the current is increased by 5A until it reaches 150A~200A, the bias voltage is increased by -5V until it reaches -130V, and the duty cycle is decreased by 5% until it reaches 20%.

9. The method for preparing an ultra-thick Zr / Ti / Ti35 corrosion-resistant coating for nuclear applications according to claim 1, characterized in that, In step four, the Zr metal transition layer is deposited using multi-arc ion plating, and the Ti / Ti35 corrosion-resistant functional layer is deposited using multi-arc ion plating, high-power pulsed magnetron sputtering, DC magnetron sputtering, radio frequency magnetron sputtering, or evaporation plating.

Images