Corrosion-resistant composite coating, and high-energy pulse magnetron sputtering preparation method and application thereof

Abstract

This invention relates to the field of coating preparation technology, and more particularly to a corrosion-resistant composite coating and its preparation method and application by high-energy pulsed magnetron sputtering. The corrosion-resistant composite coating provided by this invention adopts a metal / ceramic bilayer structure, structurally comprising a Cr transition layer and a CrN functional layer, combining the synergistic advantages of the Cr transition layer and the CrN functional layer. The Cr transition layer is in direct contact with the substrate, while the CrN phase in the CrN functional layer exhibits a preferred orientation on the (200) plane. The Cr transition layer has a dense structure and good wettability with the substrate, while the CrN functional layer has high chemical inertness. The synergistic effect of these two layers forms a highly efficient physical and chemical dual protective barrier. The corrosion-resistant composite coating provided by this invention is uniform and dense overall, with no obvious cracks, pores, or other defects on the surface and cross-section. It can effectively block water vapor corrosion, significantly improving the safety and reliability of the substrate under accident conditions, and has good engineering application prospects.

Description

Technical Field

[0001] This invention relates to the field of coating preparation technology, and in particular to a corrosion-resistant composite coating and its preparation method and application by high-energy pulsed magnetron sputtering. Background Technology

[0002] In a nuclear reactor system, the fuel cladding serves to contain nuclear fuel, support fuel assemblies, and isolate the coolant. It is the first line of defense against nuclear fuel leakage and ensures the safe operation of the reactor. Traditional fuel cladding includes zirconium alloy cladding, but under extreme accident conditions, zirconium alloy cladding can react violently with water vapor, causing it to fail and producing large amounts of hydrogen gas, which can easily lead to an explosion.

[0003] To address the aforementioned problems with traditional fuel cladding, engineers have developed a series of accident-resistant materials. Among them, silicon carbide fiber / silicon carbide ceramic (SiC) is an example. f The SiC composite material has significant performance advantages and is expected to replace traditional zirconium alloy fuel cladding in nuclear reactors. f / SiC composite materials exhibit stable performance at high temperatures, possess excellent radiation stability, and have 25% higher neutron economy than zirconium alloys, without any hydrogen-induced degradation mechanism.

[0004] However, SiC f Silicon carbide (SiC) composite materials still face many challenges in actual reactor service environments. For example, under high-temperature conditions, SiC reacts with water, initially forming silicon dioxide (SiO2), which then further reacts to form orthosilicic acid (Si(OH)4). This process leads to a continuous loss of fuel cladding thickness, ultimately causing fuel cladding failure. Furthermore, the corrosion products dissolved in the reactor coolant can negatively impact the reactor cooling system and fuel assemblies, further exacerbating operational risks.

[0005] Therefore, how to improve the corrosion resistance of SiC materials to meet the material performance requirements for fuel cladding is a problem faced in this field. Summary of the Invention

[0006] In view of this, the present invention provides a corrosion-resistant composite coating, its preparation method by high-energy pulsed magnetron sputtering, and its application. The corrosion-resistant composite coating provided by the present invention has a dense structure, strong adhesion, and excellent high-temperature stability.

[0007] The present invention provides a corrosion-resistant composite coating comprising a Cr transition layer and a CrN functional layer covering one side surface of the Cr transition layer; wherein the CrN phase in the CrN functional layer has a preferred orientation of the (200) plane.

[0008] Preferably, the total thickness of the corrosion-resistant composite coating is 2.10~5.14 μm.

[0009] Preferably, the corrosion-resistant composite coating is prepared by high-energy pulsed magnetron sputtering, and the deposition rate of the Cr transition layer is 0.54~0.93 μm / h; the deposition rate of the CrN functional layer is 0.26~1.10 μm / h.

[0010] The present invention also provides a method for preparing the corrosion-resistant composite coating described above, comprising the following steps: The substrate is subjected to ion sputtering cleaning and high-energy pulsed magnetron sputtering in sequence. The high-energy pulsed magnetron sputtering includes the sequential deposition of a Cr transition layer and a CrN functional layer to obtain the corrosion-resistant composite coating.

[0011] Preferably, the ion sputtering cleaning temperature is 245~255 °C, and the vacuum degree is ≤5×10⁻⁶. -3 Pa; The ion sputtering cleaning includes sequentially performing Ar ion sputtering cleaning and Cr ion sputtering cleaning.

[0012] Preferably, the parameters for the Ar ion sputtering cleaning include: argon flow rate of 450~550 sccm, chamber pressure of 1.8~2.2 Pa, bias voltage of -780~-820 V, duty cycle of 22~27%, and cleaning time of 10~20 min.

[0013] Preferably, the parameters for the Cr ion sputtering cleaning include: argon flow rate of 330~350 sccm, chamber pressure of 0.9~1.1 Pa, DC power supply current of Cr target of 950~1050 mA, bias voltage of -380~-420 V, duty cycle of 75~85%, and cleaning time of 10~20 min.

[0014] Preferably, the parameters for depositing the Cr transition layer include: the deposition is carried out in a protective atmosphere; the chamber pressure is 0.2~1.2 Pa, the bias voltage is 0~-200 V, the duty cycle is 75~85%, the high-energy pulse power is 1.8~2.2 kW, the pulse time is 25~100 μs, the pulse frequency is 450~550 Hz, pre-sputtering is performed before deposition, the pre-sputtering time is 5~10 min, and the deposition time is 110~130 min.

[0015] Preferably, the parameters for depositing the CrN functional layer include: being carried out in a protective atmosphere, which is a mixture of argon and nitrogen, with a nitrogen to argon flow rate ratio of 1:0.9~1.1, a chamber pressure of 0.4~1.3 Pa, a bias voltage of 0~-200 V, a duty cycle of 75~85%, a high-energy pulse power of 1.8~2.2 kW, a pulse duration of 95~105 μs, a pulse frequency of 100~700 Hz, pre-sputtering before deposition for 5~10 min, and a deposition time of 230~250 min.

[0016] The present invention also provides the application of the corrosion-resistant composite coating described in the above-described scheme or the corrosion-resistant composite coating obtained by the preparation method described in the above-described scheme as a fuel cladding.

[0017] Compared with the prior art, the present invention has achieved the following beneficial effects: To address the problems encountered in the application of fuel cladding in nuclear reactors, this invention, based on high-energy pulsed magnetron sputtering technology, utilizes stepwise cleaning and precise control of high-energy pulsed magnetron sputtering process parameters (e.g., negative bias voltage, deposition pressure) to achieve the desired effect on a substrate (e.g., SiC material). f By depositing a corrosion-resistant composite coating on the surface of SiC composite materials, the microstructure, density, internal stress, and thickness of the Cr transition layer and CrN functional layer can be systematically controlled to form a corrosion-resistant composite coating with a dense structure, strong bonding, and excellent high-temperature stability. This improves the corrosion resistance of the substrate and provides an effective solution for surface protection when the substrate is used as fuel cladding. It has important practical significance for improving the corrosion resistance and service stability of the substrate in high-temperature water environments.

[0018] The corrosion-resistant composite coating provided by this invention adopts a metal / ceramic dual-layer structure, which includes a Cr transition layer and a CrN functional layer, combining the synergistic advantages of the Cr transition layer and the CrN functional layer. The Cr transition layer is in direct contact with the substrate, while the CrN phase in the CrN functional layer exhibits a preferred orientation on the (200) plane. The Cr transition layer has a dense structure and good wettability with the substrate, while the CrN functional layer has high chemical inertness. Together, they form a highly efficient physical and chemical dual protective barrier. The corrosion-resistant composite coating provided by this invention is uniform and dense overall, with no obvious cracks, pores, or other defects on the surface and cross-section. It can effectively block water vapor corrosion, significantly improving the safety and reliability of the substrate under accident conditions, and has good prospects for engineering applications.

[0019] Compared to traditional coating preparation methods such as chemical vapor deposition (CVD), the preparation method provided by this invention has advantages such as high ionization rate, high deposited particle energy, good coating quality, and low deposition temperature, significantly reducing the risk of thermal damage to the substrate. Furthermore, the steps are simple, process parameters are controllable, and costs are manageable, making it promising for industrial application. Compared to traditional zirconium alloy cladding electroplating coating technology, this invention not only avoids the emission of heavy metal pollutants such as hexavalent chromium, but also provides a corrosion-resistant composite coating with superior diffusion barrier capabilities for fission products. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of this invention, the accompanying drawings used in the embodiments of this invention or in the prior art are briefly described below. For those skilled in the art, other drawings can be derived from the following drawings without creative effort, and all such drawings are within the protection scope of this invention.

[0021] Figure 1 This is a scanning electron microscope image of the surface morphology of the CrN functional layer in Example 1; Figure 2 The images shown are scanning electron microscope (SEM) images of the fracture morphology of the CrN functional layer in Example 1; where a is the SEM image of the fracture morphology of the CrN functional layer prepared under a nitrogen flow rate of 10 sccm, b is the SEM image of the fracture morphology of the CrN functional layer prepared under a nitrogen flow rate of 20 sccm, c is the SEM image of the fracture morphology of the CrN functional layer prepared under a nitrogen flow rate of 30 sccm, d is the SEM image of the fracture morphology of the CrN functional layer prepared under a nitrogen flow rate of 40 sccm, and e is the SEM image of the fracture morphology of the CrN functional layer prepared under a nitrogen flow rate of 50 sccm. Figure 3 The XRD patterns of CrN functional layers prepared under different nitrogen flow rates in Example 1 are shown below. Figure 4 The images show scanning electron microscope (SEM) images of the fracture morphology of the corrosion-resistant composite coatings prepared under different bias conditions in Example 2; where a is the corrosion-resistant composite coating prepared under bias conditions of 0 to -1 V, b is the corrosion-resistant composite coating prepared under bias conditions of -2 to -50 V, and c is the corrosion-resistant composite coating prepared under bias conditions of -3 to -100 V. Figure 5 The images show scanning electron microscope (SEM) images of the fracture morphology of the corrosion-resistant composite coatings prepared under different deposition pressure conditions in Example 3; where a is the corrosion-resistant composite coating prepared under a deposition pressure of 0.4 Pa, b is the corrosion-resistant composite coating prepared under a deposition pressure of 0.7 Pa, and c is the corrosion-resistant composite coating prepared under a deposition pressure of 1.0 Pa. Figure 6The image shows a scanning electron microscope (SEM) image of the corrosion-resistant composite coating in Test Example 1 after high-temperature water-oxygen corrosion at 1200 °C; where 1 represents the corrosion-resistant composite coating. Detailed Implementation

[0022] The present invention provides a corrosion-resistant composite coating comprising a Cr transition layer and a CrN functional layer covering one side surface of the Cr transition layer.

[0023] In this invention, the CrN phase in the CrN functional layer preferably has a preferred orientation of the (200) plane.

[0024] In this invention, the total thickness of the corrosion-resistant composite coating is preferably 2.10~5.14 μm, more preferably 2.5~5 μm, and even more preferably 3~4 μm.

[0025] In this invention, the corrosion-resistant composite coating is preferably prepared by high-energy pulsed magnetron sputtering. The deposition rate of the Cr transition layer is preferably 0.54~0.93 μm / h, and the deposition rate of the CrN functional layer is preferably 0.26~1.10 μm / h. By employing the above deposition rates, this invention controls the thickness or thickness ratio of the Cr transition layer and the CrN functional layer, while ensuring the quality of the corrosion-resistant composite coating and avoiding the formation of a porous structure in the coating that may result from excessively high deposition rates.

[0026] The present invention also provides a method for preparing the corrosion-resistant composite coating described above, comprising the following steps: The substrate was subjected to ion sputtering cleaning and high-energy pulsed magnetron sputtering in sequence to obtain the corrosion-resistant composite coating.

[0027] In this invention, the substrate is preferably SiC material or zirconium alloy material; the SiC material is preferably SiC fuel cladding tube or SiC block; and the zirconium alloy material is preferably zirconium alloy fuel cladding.

[0028] In this invention, the substrate is preferably pretreated before use; the pretreatment preferably includes sequential cleaning and drying; the cleaning is preferably ultrasonic cleaning; the ultrasonic frequency of the ultrasonic cleaning is preferably 35~45 kHz, specifically 40 kHz; the cleaning time is preferably 10~20 min, specifically 15 min; the ultrasonic cleaning is preferably carried out in ethanol; the mass fraction of the ethanol is preferably ≥99.7%; the drying temperature is preferably 38~42 ℃, specifically 40 ℃, and the holding time is preferably 2~4 h, specifically 2.5 h, 3 h or 3.5 h.

[0029] In this invention, the process of evacuation, heating, and heat preservation are preferably performed sequentially before ion sputtering cleaning; the heating time is preferably 22-27 min, specifically 25 min; the heat preservation time is preferably 9.5-10.5 h, specifically 10 h. The target vacuum level and target heating temperature in this invention are the temperature and vacuum level of the ion sputtering cleaning process.

[0030] In this invention, the preferred temperature for ion sputtering cleaning is 245~255 °C, specifically 250 °C, and the preferred vacuum degree is ≤5×10⁻⁶. -3 Pa; the ion sputtering cleaning preferably includes sequential Ar ion sputtering cleaning and Cr ion sputtering cleaning.

[0031] In this invention, the preferred parameters for Ar ion sputtering cleaning include: argon flow rate of 450~550 sccm, specifically 500 sccm; chamber pressure of 1.8~2.2 Pa, specifically 2.0 Pa; bias voltage of -780~-820 V, specifically -800 V; duty cycle of 22~27%, specifically 25%; and cleaning time of 10~20 min, specifically 15 min.

[0032] In this invention, the Ar ion sputtering cleaning preferably includes the following steps: rotating the substrate in front of the Cr target, setting the argon gas flow rate, introducing argon gas, controlling the opening of the gate valve, adjusting the chamber pressure of the vacuum chamber, setting the bias voltage and duty cycle, and performing sputtering cleaning after the parameters stabilize.

[0033] In this invention, the preferred parameters for Cr ion sputtering cleaning include: argon flow rate of 330~350 sccm, specifically 340 sccm; chamber pressure of 0.9~1.1 Pa, specifically 1.0 Pa; DC power supply current for the Cr target of 950~1050 mA, specifically 1000 mA; bias voltage of -380~-420 V, specifically -400 V; duty cycle of 75~85%, specifically 80%; and cleaning time of 10~20 min, specifically 15 min. This invention activates the substrate surface through high-energy Ar ion sputtering cleaning and Cr ion sputtering cleaning.

[0034] In this invention, the Cr ion sputtering cleaning preferably includes the following steps: adjusting the argon gas flow rate, controlling the gate valve opening, adjusting the chamber pressure of the vacuum chamber, adjusting the DC power supply parameters, bias voltage and duty cycle of the Cr target, and performing sputtering cleaning after the parameters stabilize.

[0035] In this invention, the high-energy pulsed magnetron sputtering preferably includes the sequential deposition of a Cr transition layer and a CrN functional layer.

[0036] In this invention, the preferred parameters for depositing the Cr transition layer include: deposition is carried out in a protective atmosphere, specifically argon gas, with an argon flow rate of 30~200 sccm (specifically 50 sccm, 80 sccm, 120 sccm, 150 sccm, or 180 sccm); chamber pressure is 0.2~1.2 Pa (specifically 0.5 Pa, 0.8 Pa, or 1 Pa); bias voltage is 0~-200 V (specifically -100 V); duty cycle is 75~85% (specifically 80%); high-energy pulse power is 1.8~2.2 kW (specifically 2 kW); pulse duration is 25~100 μs (specifically 50 μs, 70 μs, or 85 μs); pulse frequency is 450~550 Hz (specifically 500 Hz); pre-sputtering is performed before deposition for 5~10 min (specifically 7 min); and deposition time is 110~130 min (specifically 120 min).

[0037] In this invention, the preferred parameters for depositing the CrN functional layer include: deposition in a protective atmosphere, specifically a mixture of argon and nitrogen, with an argon flow rate of 10–50 sccm (specifically 20 sccm, 30 sccm, or 40 sccm), a nitrogen to argon flow rate ratio of 1:0.9–1.1 (specifically 1:1), a chamber pressure of 0.4–1.3 Pa, a bias voltage of 0–-200 V (specifically -50 V, -100 V, or -150 V), a duty cycle of 75–85% (specifically 80%), a high-energy pulse power of 1.8–2.2 kW (specifically 2 kW), a pulse duration of 95–105 μs (specifically 100 μs), a pulse frequency of 100–700 Hz (specifically 300 Hz or 500 Hz), and pre-sputtering before deposition for 5–10 min (specifically 7 min). The deposition time is 230-250 min, specifically 240 min.

[0038] The present invention also provides the application of the corrosion-resistant composite coating described in the above-described scheme or the corrosion-resistant composite coating obtained by the preparation method described in the above-described scheme as a fuel cladding.

[0039] To further illustrate the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and embodiments.

[0040] Example 1: In this embodiment, CrN functional layers are prepared under different nitrogen flow rates. The specific steps are as follows: (1) Ultrasonic cleaning: The SiC clad tube was ultrasonically cleaned for 15 min with 99.7% ethanol at a mass fraction of 40 kHz, and then dried in an oven at 40 ℃ for 3 h to obtain the cleaned SiC clad tube. (2) Equipment preparation: After turning on the high-energy pulsed magnetron sputtering equipment, place the cleaned SiC clad tube on the corresponding sample stage, and evacuate the cavity to ≤5×10⁻⁶. -3 Pa, then set the temperature control program, heat to 250 ℃ after 25 min, and keep warm for 10 h; (3) Ar ion sputtering cleaning: Rotate the SiC cladding tube to the front of the Cr target, set the gas flow rate, introduce argon gas at a flow rate of 500 sccm, and at the same time control the opening of the gate valve to adjust the gas pressure in the vacuum chamber to 2.0 Pa. The bias voltage setting parameters are voltage -800V and duty cycle of 25%. After the parameters stabilize, sputter cleaning is performed for 15 min. (4) Cr ion sputtering cleaning: Reduce the argon flow rate to 340 sccm, while controlling the gate valve opening, adjust the vacuum chamber pressure to 1.0 Pa, adjust the Cr target power supply parameters DC to 1000 mA, set the bias voltage parameters to voltage -400 V, and the duty cycle to 80%, and sputter cleaning for 15 min after the parameters stabilize. (5) Deposition of CrN functional layer: Adjust the argon flow rate to 10 sccm, 20 sccm, 30 sccm, 40 sccm and 50 sccm and introduce nitrogen gas. The argon and nitrogen flow rate ratio is 1:1. At the same time, control the gate valve opening and adjust the pressure of the vacuum chamber to 0.4 Pa. The bias voltage setting parameters are voltage -100 V, duty cycle 80%, and high energy pulse setting parameters are power 2 kW, pulse width 100 μs, pulse frequency 500 Hz. After the parameters stabilize, perform pre-sputtering for 7 min and then deposit for 240 min to obtain CrN functional layer on the surface of SiC cladding tube.

[0041] In this embodiment, the thicknesses of the CrN functional layers prepared under different nitrogen flow rates (10 sccm, 20 sccm, 30 sccm, 40 sccm, and 50 sccm) were 2.32 μm, 2.34 μm, 2.56 μm, 2.17 μm, and 2.18 μm, respectively, and the deposition rates of the CrN functional layers were 0.58 μm / h, 0.59 μm / h, 0.64 μm / h, 0.54 μm / h, and 0.54 μm / h, respectively.

[0042] The morphology of the CrN functional layer prepared in this embodiment under a nitrogen flow rate of 30 sccm is as follows. Figure 1 As shown. According to Figure 1It can be seen that the CrN functional layer has a dense structure and a "granular" surface.

[0043] The cross-sections of the CrN functional layers prepared under different nitrogen flow rates in this embodiment were analyzed, and the results are as follows: Figure 2 As shown. According to Figure 2 It can be seen that with the increase of nitrogen flow rate, the thickness and deposition rate of the CrN functional layer first increase and then decrease, reaching the maximum when the nitrogen flow rate is 30 sccm.

[0044] XRD analysis was performed on the CrN functional layers prepared under different nitrogen flow rates in this embodiment. The results are as follows: Figure 3 As shown. According to Figure 3 It can be seen that the CrN functional layer was successfully prepared in this embodiment, and it exhibits a preferred orientation of the (200) plane.

[0045] Example 2: In this embodiment, a corrosion-resistant composite coating is prepared under different bias conditions. Steps (1) to (4) in the preparation method are the same as in Example 1, except that: (5) Deposition of Cr transition layer: Adjust the argon flow rate to 30 sccm, and at the same time control the gate valve opening, adjust the pressure of the vacuum chamber to 0.6 Pa, set the bias voltage parameters as voltage 0~-1 V, -2~-50 V and -3~-100 V, duty cycle 80%, set the high energy pulse parameters as power 2 kW, pulse width 100 μs, pulse frequency 500 Hz, and after the parameters stabilize, perform pre-sputtering for 7 min, and then deposit the Cr transition layer for 120 min; (6) Deposition of CrN functional layer: Adjust the argon flow rate to 30 sccm and introduce nitrogen gas. The flow ratio of argon to nitrogen gas is 1:1. At the same time, control the opening of the gate valve and adjust the pressure of the vacuum chamber to 0.4 Pa. The bias voltage setting parameters are voltage 0~-1V, -2~-50V and -3~-100V, duty cycle 80%, high energy pulse setting parameters are power 2 kW, pulse width 100 μs, pulse frequency 500 Hz. After the parameters stabilize, perform pre-sputtering for 7 min, and then deposit the CrN functional layer for 240 min to obtain corrosion resistant composite coating.

[0046] In this embodiment, the thicknesses of the Cr transition layer prepared under different bias conditions (0~-1 V, -2~-50 V, -3~-100 V) were 1.07 μm, 1.62 μm and 1.38 μm, respectively; the thicknesses of the CrN functional layer were 1.03 μm, 2.43 μm and 2.24 μm, respectively.

[0047] In this embodiment, the deposition rates of the Cr transition layer prepared under different bias voltages (0~-1 V, -2~-50 V, -3~-100 V) were 0.54 μm / h, 0.81 μm / h, and 0.69 μm / h, respectively, and the deposition rates of the CrN functional layer were 0.26 μm / h, 0.61 μm / h, and 0.56 μm / h, respectively.

[0048] Cross-sectional analysis was performed on the corrosion-resistant composite coatings prepared under different bias conditions in this embodiment, and the results are as follows: Figure 4 As shown. According to Figure 4 It can be seen that as the bias voltage increases, the thickness and deposition rate of the corrosion-resistant composite coating first increase and then decrease, reaching the maximum at a bias voltage of -50 V.

[0049] Example 3: In this embodiment, a corrosion-resistant composite coating was prepared under different deposition pressure conditions. The steps (1) to (4) in the preparation method are the same as in Example 1, except that: (5) Deposition of Cr transition layer: Other conditions are the same as in Example 2, except that the bias voltage is a constant value of -100 V; (6) Deposition of CrN functional layer: Other conditions are the same as in Example 2, except that the bias voltage is a constant value of -100V and the deposition gas pressure is adjusted to 0.4 Pa, 0.7 Pa or 1.0 Pa.

[0050] In this embodiment, the thicknesses of the Cr transition layer prepared under different deposition pressures (0.4 Pa, 0.7 Pa, 1.0 Pa) were 1.38 μm, 1.77 μm, and 1.85 μm, respectively; and the thicknesses of the CrN functional layer were 2.24 μm, 2.95 μm, and 3.29 μm, respectively.

[0051] In this embodiment, the deposition rates of the Cr transition layer prepared under different deposition pressures (0.4 Pa, 0.7 Pa, 1.0 Pa) were 0.69 μm / h, 0.89 μm / h, and 0.93 μm / h, respectively, and the deposition rates of the CrN functional layer were 0.56 μm / h, 0.74 μm / h, and 1.1 μm / h, respectively.

[0052] The corrosion-resistant composite coatings prepared under different deposition pressure conditions in this embodiment are as follows: Figure 5 As shown. According to Figure 5 It can be seen that with the increase of deposition pressure, the thickness and deposition rate of the corrosion-resistant composite coating show an upward trend, reaching the maximum at a deposition pressure of 1.0 Pa.

[0053] Test Example 1: High-temperature water-oxygen corrosion test was conducted on the corrosion-resistant composite coating prepared under conditions of -3 to -100 V in Example 2: The SiC clad tube (sample) coated with the corrosion-resistant composite coating was subjected to high-temperature water-oxygen corrosion. First, the sample was placed in a tube furnace, and the temperature was raised along with the furnace. The temperature control was as follows: Initially, the temperature was increased from room temperature at a rate of 5 °C / min, while argon gas (flow rate of 50 sccm) was introduced. When the furnace temperature reached 200 °C, water vapor at 200 °C (flow rate of 0.5 mL / min) was continuously introduced into the sample until the temperature reached 1200 °C. After oxidation under 1200 °C water vapor for 30 min, the water vapor was turned off, and the sample was removed when the furnace cooled to 300 °C. It was then cooled again under an argon atmosphere. The results are as follows: Figure 6 As shown.

[0054] according to Figure 6 It can be seen that a 2 μm thick Cr2O3 oxide layer was formed on the sample surface, which can effectively protect the substrate from oxidation and has good corrosion resistance.

[0055] The embodiments of the present invention have been described above; however, these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. All other embodiments obtained by those skilled in the art based on the above embodiments of the present invention without inventive effort are within the protection scope of the present invention.

Claims

1. A corrosion-resistant composite coating, characterized in that, Includes a Cr transition layer and a CrN functional layer covering one side surface of the Cr transition layer; The CrN phase in the CrN functional layer has a preferred orientation of the (200) plane.

2. The corrosion-resistant composite coating according to claim 1, characterized in that, The total thickness of the corrosion-resistant composite coating is 2.10~5.14 μm.

3. The corrosion-resistant composite coating according to claim 1, characterized in that, The corrosion-resistant composite coating was prepared by high-energy pulsed magnetron sputtering. The deposition rate of the Cr transition layer was 0.54~0.93 μm / h, and the deposition rate of the CrN functional layer was 0.26~1.10 μm / h.

4. A method for preparing a corrosion-resistant composite coating, characterized in that, The corrosion-resistant composite coating is the corrosion-resistant composite coating according to any one of claims 1 to 3, and includes the following steps: The substrate is subjected to ion sputtering cleaning and high-energy pulsed magnetron sputtering in sequence. The high-energy pulsed magnetron sputtering includes the sequential deposition of a Cr transition layer and a CrN functional layer to obtain the corrosion-resistant composite coating.

5. The preparation method according to claim 4, characterized in that, The ion sputtering cleaning temperature is 245~255℃, and the vacuum degree is ≤5×10⁻⁶. -3 Pa; The ion sputtering cleaning includes sequentially performing Ar ion sputtering cleaning and Cr ion sputtering cleaning.

6. The preparation method according to claim 5, characterized in that, The parameters for Ar ion sputtering cleaning include: argon flow rate of 450~550 sccm, chamber pressure of 1.8~2.2 Pa, bias voltage of -780~-820 V, duty cycle of 22~27%, and cleaning time of 10~20 min.

7. The preparation method according to claim 5, characterized in that, The parameters for Cr ion sputtering cleaning include: argon flow rate of 330~350 sccm, chamber pressure of 0.9~1.1 Pa, DC power supply current of Cr target of 950~1050 mA, bias voltage of -380~-420 V, duty cycle of 75~85%, and cleaning time of 10~20 min.

8. The preparation method according to claim 4, characterized in that, The parameters for depositing the Cr transition layer include: the deposition is carried out in a protective atmosphere, with a chamber pressure of 0.2~1.2 Pa, a bias voltage of 0~-200 V, a duty cycle of 75~85%, a high-energy pulse power of 1.8~2.2 kW, a pulse duration of 25~100 μs, a pulse frequency of 450~550 Hz, pre-sputtering before deposition for 5~10 min, and a deposition time of 110~130 min.

9. The preparation method according to claim 4, characterized in that, The parameters for depositing the CrN functional layer include: the deposition is carried out in a protective atmosphere, which is a mixture of argon and nitrogen, with a nitrogen to argon flow rate ratio of 1:0.9~1.1, a chamber pressure of 0.4~1.3 Pa, a bias voltage of 0~-200 V, a duty cycle of 75~85%, a high-energy pulse power of 1.8~2.2 kW, a pulse duration of 95~105 μs, a pulse frequency of 100~700 Hz, pre-sputtering before deposition for 5~10 min, and a deposition time of 230~250 min.

10. The application of a corrosion-resistant composite coating as a fuel cladding, characterized in that, The corrosion-resistant composite coating is the corrosion-resistant composite coating according to any one of claims 1 to 3.

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