CN116043222A - High-temperature-resistant corrosion-resistant protective coating containing multilayer structure and preparation method thereof - Google Patents

Abstract

The invention belongs to the technical field of accident-tolerant fuel cladding coatings, and in particular relates to a high-temperature and corrosion-resistant protective coating with a multilayer structure and a preparation method thereof. The high-temperature and corrosion-resistant protective coating containing a multilayer structure sequentially includes a Mo-Zr layer, a Cr-Mo layer and a metal Cr layer from the inside to the outside. The multi-layer structure coating prepared by the invention is uniform and dense, which effectively blocks the contact between the external corrosive medium and the zirconium alloy substrate, greatly improves the stability and corrosion resistance of the zirconium alloy, thereby solving the problem of the zirconium alloy cladding in a dehydration accident. the issue of nuclear fuel leakage.

Description

A high-temperature and corrosion-resistant protective coating containing a multilayer structure and its preparation method

technical field

The invention belongs to the technical field of accident-tolerant fuel cladding coatings, and in particular relates to a high-temperature and corrosion-resistant protective coating with a multilayer structure and a preparation method thereof.

Background technique

Zirconium alloys have low thermal neutron absorption cross section, good thermal conductivity and moderate mechanical properties, etc., and are widely used in the preparation of nuclear fuel cladding tubes. However, under the conditions of a water loss accident in a pressurized water reactor power station, the zirconium alloy cladding tube is rapidly oxidized and generates a large amount of hydrogen and heat, which will cause a "hydrogen explosion" and lead to a nuclear leakage accident in severe cases.

Coating modification on the surface of zirconium alloys not only has a short development period and low cost, but also does not change the traditional fuel system. Therefore, under short-term conditions, coating modification is the key to improving the high temperature steam oxidation resistance of zirconium alloy cladding. As a coating candidate material, metal Cr coating is considered to be the most promising zirconium alloy cladding protection due to its excellent thermal conductivity, high temperature steam oxidation resistance, thermal expansion coefficient similar to zirconium alloy and good compatibility. coating.

However, serious interdiffusion of elements occurred inside the Cr-plated cladding under the service conditions of high-temperature steam environment in accident conditions. On the one hand, the Cr element diffuses to the zirconium matrix, forming a brittle ZrCr ₂ layer and reducing the toughness of the coating; on the other hand, the Zr element diffuses along the grain boundaries of the Cr coating to the surface, and preferentially reacts with oxygen to form ZrO ₂ , resulting in the Cr coating The rapid diffusion channel of oxygen appears in the layer, which causes the damage and failure of the coating.

Contents of the invention

Aiming at the deficiencies in the prior art, the present invention provides a high-temperature and corrosion-resistant protective coating containing a multilayer structure and a preparation method thereof. The protective coating of the multilayer structure is well bonded to the substrate, and the surface is smooth and structured Dense, with excellent resistance to high temperature steam oxidation.

One object of the present invention is to provide a kind of high temperature and corrosion resistant protective coating that contains multilayer structure, and described high temperature and corrosion resistant protective coating that contains multilayer structure comprises Mo-Zr layer, Cr-Mo layer and metal Cr layer.

Preferably, the composition of the Mo-Zr layer is ZrMo ₂ , the composition of the Cr-Mo layer is Cr ₃ Mo, and the composition of the metal Cr layer is Cr crystal.

Preferably, the thickness of the Mo-Zr layer is 0.3-3 μm, the thickness of the Cr-Mo layer is 0.5-5 μm, and the thickness of the metal Cr layer is 5-20 μm.

Another object of the present invention is to provide a method for preparing a high temperature and corrosion resistant protective coating containing a multilayer structure, comprising the following steps:

A high temperature and corrosion resistant protective coating with a multilayer structure is obtained by direct current magnetron sputtering Mo coating on the zirconium alloy substrate, then high power pulse magnetron sputtering Cr coating on the Mo coating, and then annealing.

Preferably, in the above preparation method, the parameters of DC magnetron sputtering include: the target material is Mo, the sputtering pressure is 0.1-0.3Pa, the bias voltage is -60--100V, the sputtering power is 500-2000W, and the deposition The temperature is 100-300° C., and the deposition time is 2-8 hours.

The present invention adopts the above-mentioned parameters to carry out DC magnetron sputtering Mo coating, and the Mo coating has a compact structure and has excellent combination with the zirconium alloy substrate.

Preferably, in the above preparation method, the parameters of high-power pulse magnetron sputtering include: the target material is Cr, the sputtering pressure is 0.1-0.3Pa, the bias voltage is -60--100V, and the pulse frequency is 300-600Hz, The sputtering power is 2000-4000W, the deposition temperature is 100-300°C, and the deposition time is 6-12h.

The present invention uses high-power pulse magnetron sputtering technology (pulse frequency is 300-600Hz, sputtering power is 2000-4000W) to deposit the Cr layer on the surface. A high-density and high-energy plasma is obtained, and the prepared coating has a smooth surface, a dense structure, and a good combination with the Mo layer.

Preferably, the purity of the Mo target material and the Cr target material mentioned above are both above 99.999%.

Preferably, during the magnetron sputtering process, the rotational speed of the sample stage is maintained at 10-30 rpm, and the distance between the target and the sample during the coating sputtering deposition process is 10-13 cm.

Preferably, in the above preparation method, the sputtered Mo coating has a thickness of 1-5 μm, and the sputtered Cr coating has a thickness of 8-22 μm.

The present invention controls the thickness of the Mo coating to be 1-5 μm. During the subsequent annealing treatment, part of the Mo diffuses into the Zr matrix, and the rest of the Mo diffuses into the Cr layer, thereby forming a Mo-Zr layer and a Cr-Mo layer, and no Mo elemental layer remains .

Preferably, before performing magnetron sputtering on the zirconium alloy substrate, the Mo target and the Cr target are pre-sputtered to remove oxides or adsorbed impurities on the target surface; the pre-sputtering power is 500-2000W, and the cavity The vacuum is 1-3Pa, and the pre-sputtering time is 5-15min.

Preferably, in the above preparation method, the zirconium alloy substrate is first subjected to argon plasma etching before sputtering the Mo coating, and the etching time is 10-30 minutes. Plasma etching is performed on the zirconium alloy substrate to further clean the substrate and remove surface pollutants and oxides.

Preferably, the parameters of the argon plasma etching include: a bias voltage of -200--400V, an argon flow rate of 30-60 sccm, and an ion source current of 0.1-0.3A.

Preferably, the zirconium alloy substrate is subjected to pretreatment before argon plasma etching, and the pretreatment includes: grinding, polishing, cleaning, etc., to remove impurities on the surface of the zirconium alloy substrate.

Preferably, in the above preparation method, the annealing temperature is 800-1200° C., and the annealing time is 0.5-4 hours.

Compared with the prior art, the present invention has the following beneficial effects:

1. The protective coating of the present invention includes a Mo-Zr layer, a Cr-Mo layer and a metal Cr layer sequentially from the inside and outside, which is well bonded to the substrate, has a smooth surface and a compact structure, and is conducive to inhibiting the Cr coating from interacting with the zirconium alloy. Severe interdiffusion of elements between the substrates enhances the interface stability between the coating and the zirconium alloy substrate under the service conditions of high-temperature steam environment in accident conditions, and improves the high-temperature steam oxidation resistance of the coating;

2. The present invention uses high-power pulse magnetron sputtering technology to deposit the Cr layer on the surface. Compared with traditional DC magnetron sputtering, it can obtain high-density and high-energy plasma under high-power pulse conditions, and the prepared coating The surface is smooth, the structure is dense and it is well combined with the Mo layer.

3. Before the zirconium alloy substrate of the present invention is sputtered with the Mo coating, it is etched with argon plasma to further clean the substrate, remove surface pollutants and oxides, and improve the bonding between the coating and the substrate;

4. The thickness of the sputtered Mo layer in the present invention is further controlled to be 1-5 μm. During the subsequent annealing treatment, part of the Mo diffuses into the Zr matrix, and the remaining part of Mo diffuses into the Cr layer, thereby forming a Mo-Zr layer and a Cr-Mo layer. Mo monolayer remains.

Description of drawings

Fig. 1 is the schematic diagram that the zirconium alloy surface of the embodiment of the present invention contains the high temperature and corrosion resistant protective coating of multilayer structure;

Fig. 2 is the cross-sectional scanning electron microscope picture that the surface of the zirconium alloy of Example 1 of the present invention contains the high temperature and corrosion resistant protective coating of multilayer structure;

3 is a cross-sectional scanning electron microscope image of a single-layer Cr coating on the surface of a zirconium alloy in Comparative Example 1 of the present invention.

Detailed ways

The technical solutions of the present invention will be further described below through specific embodiments and drawings. It should be understood that the specific embodiments described here are only used to help understand the present invention, and are not intended to specifically limit the present invention. And the drawings used herein are only for better illustrating the disclosed content of the present invention, and do not limit the scope of protection. Unless otherwise specified, the raw materials used in the examples of the present invention are commonly used raw materials in the art, and the methods used in the examples are conventional methods in the art.

Example 1

The high temperature and corrosion resistant protective coating containing multilayer structure of the present embodiment includes Mo-Zr layer, Cr-Mo layer and metal Cr layer successively from inside to outside, as shown in Figure 1, and its preparation method is as follows:

a. Substrate material pretreatment: Prepare Zirlo zirconium alloy with a size of 15mm×10mm×2mm, polish the surface with 1000#, 2000#, 3000# water sandpaper in turn, then polish it, and then use acetone to ultrasonically clean it for 30min After cleaning, put it in the drying box to dry;

b. Substrate installation: fix the zirconium alloy substrate after the above treatment on the sample stage of the magnetron sputtering chamber;

c. Chamber heating and vacuum preparation: heat the magnetron sputtering chamber to 200°C, and vacuum the chamber to 3×10 ^-3 Pa;

d. Etching the substrate: Under the conditions of bias voltage of -300V, argon flow rate of 40sccm, and ion source current of 0.2A, argon plasma glow etching is performed on the substrate, and the etching time is 15 minutes;

e. Pre-sputtering: The chamber of the magnetron sputtering instrument is filled with argon gas, and the Mo target and the Cr target are pre-sputtered to remove oxides or adsorbed impurities on the target surface; the pre-sputtering power is 1000W, vacuum The temperature is 2.5Pa, and the pre-sputtering time is 15min;

f. Sputtering Mo coating: adjust the distance between the sample stage and the Mo target, feed argon gas and turn on the DC sputtering power supply, the sputtering pressure is 0.2Pa, the bias voltage is -80V, and the sputtering power is 1000W 1. The Mo target was sputtered at a deposition temperature of 200° C. for 3 hours to obtain a zirconium alloy sample deposited with a Mo coating, and then the sputtering was stopped; the thickness of the Mo coating was 3.21 μm.

g. Sputtering Cr coating: adjust the distance between the sample stage and the Cr target, pass in argon gas and turn on the high-power pulse sputtering power supply, the sputtering pressure is 0.2Pa, the bias voltage is -80V, and the pulse frequency is The Cr target was sputtered at 500Hz, the sputtering power was 3000W, and the deposition temperature was 200°C. After 8 hours of deposition, a zirconium alloy sample with a Cr/Mo coating was obtained. Stop sputtering, and the thickness of the Cr coating was 12.43 μm. , take out the sample after the temperature drops to room temperature;

h. Heat treatment: place the coated sample in an annealing furnace, and perform annealing treatment in a high vacuum (2×10 ^-3 Pa) environment at a temperature of 900° C. for 1 hour.

Through the above steps, a zirconium alloy workpiece covered with a multi-layer structural protective coating is finally obtained.

Fig. 2 is the cross-sectional scanning electron microscope picture that the surface of the zirconium alloy of the embodiment 1 of the present invention contains the high temperature and corrosion resistant protective coating of multilayer structure, it can be clearly seen that the surface of the substrate forms a three-layer structure, which is respectively Mo-Zr layer, Cr- Mo layer and metallic Cr layer. The energy spectrum point scanning analysis is carried out to the multi-layer structure coating in Fig. 2, the atomic percent of Mo in the metallic Cr layer is approximately 0, the atomic percent of Mo in the Cr-Mo layer is about 25%, and the Mo atomic percent in the Mo-Zr layer The atomic percentage is about 67%; the atomic percentage of Mo element in each layer structure is far less than 95%, indicating that there is no residual Mo elemental layer in the multilayer structure coating. After testing, the total thickness of the multilayer protective coating prepared in this example is 15.66 μm, in which the thickness of the Mo-Zr layer is 1.54 μm, the thickness of the Cr-Mo layer is 2.08 μm, and the thickness of the Cr layer is 12.04 μm.

Example 2

The high-temperature and corrosion-resistant protective coating containing a multi-layer structure in this embodiment includes a Mo-Zr layer, a Cr-Mo layer and a metal Cr layer in sequence from the inside to the outside, and the preparation method is as follows:

a. Substrate material pretreatment: prepare Zirlo zirconium alloy with a size of 15mm×10mm×2mm, use 1000#, 2000#, 3000# water sandpaper to polish the surface, then polish it, and then use alcohol to ultrasonically clean it for 30 minutes After cleaning, put it in the drying box to dry;

b. Substrate installation: fix the zirconium alloy substrate after the above treatment on the sample stage of the magnetron sputtering chamber;

c. Chamber heating and vacuum preparation: heat the magnetron sputtering chamber to 300°C, and vacuum the chamber to 3×10 ^-3 Pa;

d. Etching the substrate: Under the conditions of bias voltage of -250V, argon gas flow rate of 50sccm, and ion source current of 0.15A, argon plasma glow etching is performed on the substrate, and the etching time is 20min;

e. Pre-sputtering: The chamber of the magnetron sputtering instrument is filled with argon gas, and the Mo target and the Cr target are pre-sputtered to remove oxides or adsorbed impurities on the target surface; the pre-sputtering power is 1500W, vacuum The temperature is 2.5Pa, and the pre-sputtering time is 10min;

f. Sputtering Mo coating: adjust the distance between the sample stage and the Mo target, pass in argon gas and turn on the DC sputtering power supply, the sputtering pressure is 0.3Pa, the bias voltage is -90V, and the sputtering power is 1300W 1. The Mo target was sputtered at a deposition temperature of 300° C. for 3 hours to obtain a zirconium alloy sample deposited with a Mo coating, and then the sputtering was stopped; the thickness of the Mo coating was 4.48 μm.

g. Sputtering Cr coating: adjust the distance between the sample stage and the Cr target, pass in argon gas and turn on the high-power sputtering power supply. The sputtering pressure is 0.3Pa, the bias voltage is -80V, and the pulse frequency is 550Hz. 1. The sputtering power is 3500W, and the deposition temperature is 300°C, and the Cr target is sputtered for 7 hours to obtain a zirconium alloy sample deposited with a Cr/Mo coating. Stop sputtering, and the thickness of the Cr coating is 11.02 μm. Take out the sample after the temperature drops to room temperature;

h. Heat treatment: place the coating sample in an annealing furnace, and perform annealing treatment in a high vacuum (vacuum degree of 1×10 ^-3 Pa) environment, the temperature is 1000°C, and the time is 1h, to obtain a smooth surface and a dense structure. Layer structure protective coating.

Through the above steps, a zirconium alloy workpiece covered with a multi-layer structural protective coating is finally obtained.

After testing, the total thickness of the multilayer protective coating prepared in this example is 15.85 μm, in which the thickness of the Mo-Zr layer is 2.41 μm, the thickness of the Cr-Mo layer is 3.32 μm, and the thickness of the Cr layer is 10.12 μm.

Example 3

The difference between embodiment 3 and embodiment 1 is that the zirconium alloy substrate is not subjected to argon plasma glow etching in embodiment 3, and the others are the same as embodiment 1.

After testing, the total thickness of the multilayer structure protective coating prepared in this example is 15.32 μm, in which the thickness of the Mo-Zr layer is 1.43 μm, the thickness of the Cr-Mo layer is 1.92 μm, and the thickness of the Cr layer is 11.97 μm.

Example 4

The difference between Comparative Example 4 and Example 1 is that step g of Comparative Example 4 is: sputtering Cr coating: adjust the distance between the sample stage and the Cr target, feed argon and turn on the DC sputtering power supply, The sputtering pressure was 0.2Pa, the bias voltage was -80V, the sputtering power was 3000W, and the deposition temperature was 200°C, and the Cr target was sputtered for 3.5h to obtain a zirconium alloy sample deposited with a Cr/Mo coating. Stop sputtering, the thickness of the Cr coating is 12.41 μm, and take out the sample after the temperature drops to room temperature.

After testing, the total thickness of the multilayer protective coating prepared in this example is 15.58 μm, in which the thickness of the Mo-Zr layer is 1.53 μm, the thickness of the Cr-Mo layer is 2.16 μm, and the thickness of the Cr layer is 11.89 μm.

Comparative example 1:

The difference between this Comparative Example 1 and Example 1 is that this Comparative Example 1 only prepares a zirconium alloy workpiece covered with a single-layer Cr coating, and the preparation method is as follows:

a. Substrate material pretreatment: prepare Zirlo zirconium alloy with a size of 15mm×10mm×2mm, use 1000#, 2000#, 3000# water sandpaper to polish the surface, then polish it, and then use acetone to ultrasonically clean it for 30min After cleaning, put it in the drying box to dry;

b. Substrate installation: fix the zirconium alloy substrate after the above treatment on the sample stage of the magnetron sputtering chamber;

c. Chamber heating and vacuum preparation: heat the magnetron sputtering chamber to 200°C, and vacuum the chamber to 3×10 ^-3 Pa;

d. Etching the substrate: Under the conditions of bias voltage of -300V, argon flow rate of 40sccm, and ion source current of 0.2A, argon plasma glow etching is performed on the substrate, and the etching time is 15 minutes;

e. Pre-sputtering: The chamber of the magnetron sputtering instrument is filled with argon gas, and the Cr target is pre-sputtered to remove oxides or adsorbed impurities on the target surface; the pre-sputtering power is 1000W, and the vacuum degree is 2.5Pa , the pre-sputtering time is 15min;

f. Sputtering Cr coating: adjust the distance between the sample stage and the Cr target, pass in argon gas and turn on the high-power sputtering power supply, at a sputtering pressure of 0.2Pa, a bias voltage of -80V, and a pulse frequency of 500Hz. The sputtering power was 3000W and the deposition temperature was 200°C, and the Cr target was sputtered for 10 hours to obtain a zirconium alloy sample with a Cr coating. The sputtering was stopped, and the sample was taken out after the temperature dropped to room temperature.

Through the above steps, a zirconium alloy workpiece covered with a single-layer Cr coating on the surface is finally obtained. After testing, the thickness of the single-layer Cr coating prepared in Comparative Example 1 was 15.32 μm.

Comparative example 2

The difference between Comparative Example 2 and Example 1 is that Al ₂ O ₃ is sputtered on the surface of the zirconium alloy substrate in Comparative Example 2, and its preparation method is as follows:

a. Substrate material pretreatment: Prepare Zirlo zirconium alloy with a size of 15mm×10mm×2mm, use 1000#, 2000#, 3000# water sandpaper to polish the surface in turn, then polish it, and then use acetone alcohol to clean it ultrasonically 30min, after cleaning, put it into the drying box to dry;

b. Substrate installation: fix the zirconium alloy substrate after the above treatment on the sample stage of the magnetron sputtering chamber;

c. Chamber heating and vacuum preparation: Vacuum the magnetron sputtering chamber to 3×10 ^-3 Pa;

d. Etching the substrate: Under the conditions of bias voltage of -300V, argon gas flow rate of 40sccm, and ion source current of 0.2A, argon plasma glow etching is performed on the substrate, and the etching time is 15 minutes;

e. Pre-sputtering: The magnetron sputtering chamber is filled with argon gas, and the Al ₂ O ₃ target and the Cr target are pre-sputtered to remove oxides or adsorbed impurities on the target surface; the pre-sputtering power is 1000W, vacuum degree is 2.5Pa, pre-sputtering time is 15min;

f. Sputtering Al ₂ O ₃ coating: Adjust the distance between the sample stage and the Al target, feed in argon and oxygen and turn on the DC sputtering power supply. The sputtering pressure is 0.2Pa, the bias voltage is -80V, The sputtering power is 250W, and the deposition temperature is room temperature, and the Al target is sputtered for 6 hours to obtain a zirconium alloy sample deposited with an Al ₂ O ₃ coating, and then the sputtering is stopped;

g. Close the oxygen and Ar valves, continue the vacuuming operation, wait for the vacuum to be 3×10 ^-3 Pa, then heat the sample stage, and set the temperature to 200°C;

h. Sputtering Cr coating: adjust the distance between the sample stage and the Cr target, feed argon gas and turn on the high-power pulse sputtering power supply, the sputtering pressure is 0.2Pa, the bias voltage is -80V, and the pulse frequency is 500Hz 1. The sputtering power is 3000W, the deposition temperature is 200°C, and the Cr target is sputtered for 8 hours to obtain a zirconium alloy sample with a Cr coating. Stop sputtering, and the thickness of the Cr coating is 12.17 μm. Take out the sample after the temperature is lowered to room temperature;

i. Heat treatment: place the coated sample in an annealing furnace, and perform annealing treatment in a high vacuum (2×10 ^-3 Pa) environment at a temperature of 900° C. for 1 hour.

Through the above steps, a zirconium alloy workpiece covered with multi-layer coatings is finally obtained.

Comparative example 3

The difference between Comparative Example 3 and Example 1 is that step f of Comparative Example 3 is:

Sputtering Mo coating: adjust the distance between the sample stage and the Mo target, feed argon gas and turn on the DC sputtering power supply, at the sputtering pressure of 0.2Pa, the bias voltage of -80V, the sputtering power of 1000W, the deposition The Mo target was sputtered at a temperature of 200° C. and deposited for 15 hours to obtain a Mo coating thickness of 16.25 μm.

After testing, it was found that the surface of the zirconium alloy substrate formed a four-layer structure, which were Mo-Zr layer, Mo layer, Cr-Mo layer and metal Cr layer.

Water Vapor Corrosion Experiment of Protective Coating

The Zirlo zirconium alloy substrate, the zirconium alloy workpieces with protective coatings prepared in Examples 1-4 and Comparative Examples 1-3 were oxidized in a water vapor environment at 1200° C. for 0.5 h, and the water vapor flow rate was 1.5 g/min. In order to ensure the accuracy of the oxidation weight gain data, the number of oxidation test samples under each parameter is not less than three, and the average value of the oxidation weight gain is taken. See Table 1 for specific testing data.

Table 1

As can be seen from the data in the above table, the present invention prepares a multilayer protective coating on the Zirlo zirconium alloy surface, and its oxidation weight gain is significantly lower than the Zirlo zirconium alloy substrate and the single-layer Cr coating sample, indicating that the multilayer structure of the present invention The structural protective coating greatly enhances the accident resistance and fault tolerance of zirconium alloy workpieces. In addition, compared with the single-layer Cr coating sample, there is no obvious Zr-Cr interdiffusion layer inside the multi-layer structure protective coating sample after high-temperature steam corrosion, indicating that the multi-layer structure protective coating can effectively block Zr-Cr at high temperature. , Cr interdiffusion of two elements.

The aspects, embodiments, and features of the invention are to be considered in all respects as illustrative and not limiting, the scope of which is defined only by the claims. Other embodiments, modifications, and uses will be apparent to those skilled in the art without departing from the spirit and scope of the invention as claimed.

In the preparation method of the present invention, the order of each step is not limited to the listed order. For those of ordinary skill in the art, on the premise of not paying creative work, the sequence change of each step is also protected by the present invention. within range. Furthermore, two or more steps or actions may be performed simultaneously.

Finally, it should be noted that the specific embodiments described herein are only for illustrating the present invention, rather than limiting the implementation of the present invention. Those skilled in the technical field to which the present invention pertains may make various modifications or supplements to the described specific embodiments, or replace them in similar ways, and it is not necessary and impossible to give a full example of all the implementation modes here. However, the obvious changes or variations derived from the essential spirit of the present invention still belong to the protection scope of the present invention, and interpreting them as any additional limitation is contrary to the spirit of the present invention.

Claims (10)

1. The high-temperature-resistant corrosion-resistant protective coating containing the multilayer structure is characterized by sequentially comprising a Mo-Zr layer, a Cr-Mo layer and a metal Cr layer from inside to outside.

2. The high temperature and corrosion resistant protective coating containing a multilayer structure according to claim 1, wherein the mo—zr layer is composed of ZrMo ₂ The Cr-Mo layer comprises Cr ₃ Mo, wherein the component of the metal Cr layer is Cr crystal.

3. The high temperature and corrosion resistant protective coating containing a multilayer structure according to claim 1, wherein the thickness of the Mo-Zr layer is 0.3 to 3 μm, the thickness of the Cr-Mo layer is 0.5 to 5 μm, and the thickness of the metallic Cr layer is 5 to 20 μm.

4. A method of preparing a high temperature corrosion resistant protective coating comprising a multilayer structure as claimed in claim 1, comprising the steps of:

and performing direct-current magnetron sputtering on the Mo coating, performing high-power pulse magnetron sputtering on the Mo coating to obtain the Cr coating, and performing annealing treatment to obtain the high-temperature-resistant corrosion-resistant protective coating with the multilayer structure.

5. The method according to claim 4, wherein the parameters of the direct current magnetron sputtering include: the target material is Mo, the sputtering air pressure is 0.1-0.3 Pa, the bias voltage is-60 to-100V, the sputtering power is 500-2000W, the deposition temperature is 100-300 ℃, and the deposition time is 2-8 h.

6. The method of claim 4, wherein the parameters of high power pulsed magnetron sputtering include: the target material is Cr, the sputtering air pressure is 0.1-0.3 Pa, the bias voltage is-60 to-100V, the pulse frequency is 300-600 Hz, the sputtering power is 2000-4000W, the deposition temperature is 100-300 ℃, and the deposition time is 6-12 h.

7. The method according to claim 4, wherein the sputtered Mo coating has a thickness of 1 to 5 μm and the sputtered Cr coating has a thickness of 8 to 22. Mu.m.

8. The method according to claim 4, wherein the zirconium alloy substrate is subjected to argon plasma etching for 10 to 30 minutes before sputtering the Mo coating.

9. The method of claim 8, wherein the parameters of the argon plasma etch include: the bias voltage is-200 to-400V, the argon flow is 30-60 sccm, and the ion source current is 0.1-0.3A.

10. The method according to claim 4, wherein the annealing treatment temperature is 800 to 1200 ℃ and the time is 0.5 to 4 hours.

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