CN116043222A

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

Info

Publication number: CN116043222A
Application number: CN202211693574.2A
Authority: CN
Inventors: 柯培玲; 王郑; 汪爱英; 王振玉; 韩志超
Original assignee: Ningbo Institute of Material Technology and Engineering of CAS
Current assignee: Ningbo Institute of Material Technology and Engineering of CAS
Priority date: 2022-12-28
Filing date: 2022-12-28
Publication date: 2023-05-02

Abstract

The invention belongs to the technical field of accident-tolerant fuel cladding coatings, and particularly relates to a high-temperature-resistant corrosion-resistant protective coating with a multi-layer structure and a preparation method thereof. The high-temperature-resistant corrosion-resistant protective coating with the multilayer structure sequentially comprises a Mo-Zr layer, a Cr-Mo layer and a metal Cr layer from inside to outside. The multilayer structure coating prepared by the method is uniform and compact, effectively blocks the contact between an external corrosion medium and a zirconium alloy matrix, and greatly improves the stability and corrosion resistance of the zirconium alloy, thereby solving the problem of nuclear fuel leakage of the zirconium alloy cladding under the water loss accident working condition.

Description

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

Technical Field

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

Background

Zirconium alloy has low thermal neutron absorption section, good thermal conductivity, moderate mechanical property and the like, and is widely used for preparing nuclear fuel cladding tubes. However, under the water loss accident condition of the pressurized water reactor power station, the zirconium alloy cladding pipe is rapidly oxidized and generates a large amount of hydrogen and heat, and the nuclear leakage accident is caused by hydrogen explosion in severe cases.

The coating modification is carried out on the surface of the zirconium alloy, so that the research and development period is short, the cost is low, and the traditional fuel system is not changed, therefore, the coating modification is the key for improving the high-temperature steam oxidation resistance of the zirconium alloy cladding under the short-term condition. As a coating candidate, metallic Cr coatings are considered to be the most promising protective coating for zirconium alloy cladding due to their excellent thermal conductivity, resistance to high temperature steam oxidation, coefficient of thermal expansion close to that of zirconium alloys, and good compatibility.

However, under the service conditions of the high-temperature steam environment of the accident working condition, serious inter-diffusion of elements occurs in the Cr-plated cladding. On the one hand, cr element diffuses into the zirconium matrix to form brittle ZrCr ₂ Layer and reduce toughness of the coating; on the other hand, zr element diffuses along the grain boundary of the Cr coating to the surface and preferentially reacts with oxygen to generate ZrO ₂ Resulting in rapid diffusion of oxygen in the Cr coating, which in turn causes damage and failure of the coating.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides the high-temperature-resistant corrosion-resistant protective coating with the multilayer structure and the preparation method thereof, wherein the protective coating with the multilayer structure is better combined with a matrix, has smooth surface and compact structure, and has excellent high-temperature steam oxidation resistance.

It is an object of the present invention to provide a high temperature and corrosion resistant protective coating comprising a multi-layered structure, which comprises a Mo-Zr layer, a Cr-Mo layer and a metallic Cr layer in this order from the inside to the outside.

Preferably, the component of the Mo-Zr layer is ZrMo ₂ The Cr-Mo layer comprises Cr ₃ Mo, wherein the component of the metal Cr layer is Cr crystal.

Preferably, the thickness of the Mo-Zr layer is 0.3 to 3. Mu.m, the thickness of the Cr-Mo layer is 0.5 to 5. Mu.m, and the thickness of the metallic Cr layer is 5 to 20. Mu.m.

Another object of the present invention is to provide a method for preparing a high temperature resistant corrosion resistant protective coating comprising a multi-layered structure, 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.

Preferably, in the above preparation method, 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.

The invention adopts the parameters to carry out the direct current magnetron sputtering Mo coating, and the Mo coating has compact structure and excellent combination property with the zirconium alloy matrix.

Preferably, in the above preparation method, the parameters of the high-power pulse 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.

The invention uses high-power pulse magnetron sputtering technology (the pulse frequency is 300-600 Hz, the sputtering power is 2000-4000W) to deposit the surface Cr layer, compared with the traditional direct-current magnetron sputtering, the invention can obtain high-density high-energy plasmas under the high-power pulse condition, and the prepared coating has smooth surface, compact structure and good combination with the Mo layer.

Preferably, the purities of the Mo target and the Cr target are both 99.999% or more.

Preferably, in the magnetron sputtering process, the rotating speed of the sample table is kept at 10-30 rpm, and the distance between the target and the sample in the coating sputtering deposition process is 10-13 cm.

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

The thickness of the Mo coating is controlled to be 1-5 mu m, part of Mo is diffused into the Zr matrix during subsequent annealing treatment, and the rest of Mo is diffused into the Cr layer, so that a Mo-Zr layer and a Cr-Mo layer are formed, and no Mo simple substance layer remains.

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

Preferably, in the preparation method, the zirconium alloy substrate is subjected to argon plasma etching for 10-30 min before the Mo coating is sputtered. And performing plasma etching on the zirconium alloy matrix to further clean the matrix and remove surface pollutants and oxides.

Preferably, the parameters of the argon plasma etching 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.

Preferably, the zirconium alloy substrate is pre-treated prior to argon plasma etching, the pre-treatment comprising: grinding, polishing, cleaning and the like to remove impurities on the surface of the zirconium alloy substrate.

Preferably, in the above preparation method, the annealing treatment temperature is 800 to 1200 ℃ and the annealing time is 0.5 to 4 hours.

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

1. the protective coating comprises a Mo-Zr layer, a Cr-Mo layer and a metal Cr layer sequentially from inside to outside, is well combined with a matrix, has smooth surface and compact structure, is favorable for inhibiting serious element interdiffusion between the Cr coating and a zirconium alloy matrix, enhances the interface stability of the coating and the zirconium alloy matrix under the service condition of a high-temperature steam environment under the accident working condition, and improves the high-temperature steam oxidation resistance of the coating;

2. compared with the traditional direct current magnetron sputtering, the high-density high-energy plasma can be obtained under the high-power pulse condition, and the prepared coating has smooth surface, compact structure and good combination with the Mo layer.

3. Before sputtering the Mo coating, the zirconium alloy substrate is etched by argon plasma to further clean the substrate, remove surface pollutants and oxides and improve the combination property of the coating and the substrate;

4. the thickness of the sputtered Mo layer is further controlled to be 1-5 mu m, part of Mo is diffused into the Zr matrix during subsequent annealing treatment, and the rest of Mo is diffused into the Cr layer, so that a Mo-Zr layer and a Cr-Mo layer are formed, and no Mo simple substance layer remains.

Drawings

FIG. 1 is a schematic view of a zirconium alloy surface having a multi-layer structured high temperature corrosion resistant protective coating in accordance with an embodiment of the present invention;

FIG. 2 is a cross-sectional scanning electron microscope image of the zirconium alloy surface of example 1 of the present invention containing a multi-layer structure of a high temperature resistant corrosion resistant protective coating;

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

Detailed Description

The technical solution of the present invention will be further described by means of specific examples and drawings, it being understood that the specific examples described herein are only for aiding in understanding the present invention and are not intended to be limiting. And the drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure. Unless otherwise indicated, all materials used in the examples of the present invention are those commonly used in the art, and all methods used in the examples are those commonly used in the art.

Example 1

The high temperature resistant and corrosion resistant protective coating with a multilayer structure in this embodiment sequentially comprises a Mo-Zr layer, a Cr-Mo layer and a metallic Cr layer from inside to outside, as shown in fig. 1, and the preparation method thereof is as follows:

a. pretreatment of a matrix material: preparing Zirlo zirconium alloy with the size of 15mm multiplied by 10mm multiplied by 2mm, sequentially polishing the surface by using No. 1000, no. 2000 and No. 3000 water sand paper, polishing, ultrasonically cleaning the zirconium alloy by using acetone for 30min, and drying in a drying oven after cleaning;

b. and (3) base body installation: fixing the zirconium alloy matrix after the treatment on a sample stage of a magnetron sputtering instrument cavity;

c. cavity heating and vacuum preparation: heating the cavity of the magnetron sputtering instrument to 200 ℃ and vacuumizing the cavity to 3 multiplied by 10 ^-3 Pa；

d. Etching a substrate: performing argon plasma glow etching on the substrate under the conditions of a bias voltage of-300V, an argon flow of 40sccm and an ion source current of 0.2A for 15min;

e. pre-sputtering: argon is introduced into the cavity of the magnetron sputtering instrument, and pre-sputtering is carried out on the Mo target and the Cr target so as to remove oxides or adsorbed impurities on the surface of the target; the pre-sputtering power is 1000W, the vacuum degree is 2.5Pa, and the pre-sputtering time is 15min;

f. sputtering a Mo coating: adjusting the distance between a sample stage and a Mo target, introducing argon and starting a direct-current sputtering power supply, sputtering the Mo target under the conditions of sputtering air pressure of 0.2Pa, bias voltage of-80V, sputtering power of 1000W and deposition temperature of 200 ℃ for 3 hours to obtain a zirconium alloy sample deposited with a Mo coating, and then stopping sputtering; the Mo coating thickness was 3.21 μm.

g. Sputtering Cr coating: adjusting the distance between a sample stage and a Cr target, introducing argon, starting a high-power pulse sputtering power supply, sputtering the Cr target under the conditions of sputtering air pressure of 0.2Pa, bias voltage of-80V, pulse frequency of 500Hz, sputtering power of 3000W and deposition temperature of 200 ℃, depositing for 8 hours to obtain a zirconium alloy sample deposited with a Cr/Mo coating, stopping sputtering, keeping the thickness of the Cr coating at 12.43 mu m, and taking out the sample after isothermal reduction to room temperature;

h. and (3) heat treatment: the coating sample was placed in an annealing furnace under high vacuum (vacuum degree of 2×10 ^-3 Pa) and annealing at 900 ℃ for 1h.

Through the steps, the zirconium alloy workpiece with the surface covered with the protective coating with the multilayer structure is finally obtained.

FIG. 2 is a cross-sectional scanning electron microscope image of the zirconium alloy surface of the embodiment 1 of the invention containing a high temperature and corrosion resistant protective coating with a multi-layer structure, and it can be clearly seen that the surface of the substrate forms a three-layer structure, which is a Mo-Zr layer, a Cr-Mo layer and a metallic Cr layer respectively. The multi-layer structural coating of FIG. 2 was analyzed by energy point scan analysis, wherein the atomic percent of Mo in the metallic Cr layer was approximately 0, the atomic percent of Mo in the Cr-Mo layer was approximately 25%, and the atomic percent of Mo in the Mo-Zr layer was approximately 67%; the atomic percentage of Mo element in each layer of structure is far less than 95%, which indicates that the multi-layer structure coating has no Mo simple substance layer residue. The total thickness of the protective coating layer of the multilayer structure prepared in this example was found to be 15.66. Mu.m, wherein the thickness of the Mo-Zr layer was 1.54. Mu.m, the thickness of the Cr-Mo layer was 2.08. Mu.m, and the thickness of the Cr layer was 12.04. Mu.m.

Example 2

The high-temperature-resistant corrosion-resistant protective coating with the multilayer structure comprises a Mo-Zr layer, a Cr-Mo layer and a metal Cr layer from inside to outside, and the preparation method comprises the following steps:

a. pretreatment of a matrix material: preparing Zirlo zirconium alloy with the size of 15mm multiplied by 10mm multiplied by 2mm, sequentially polishing the surface by using No. 1000, no. 2000 and No. 3000 water sand paper, polishing, ultrasonically cleaning the zirconium alloy for 30min by using alcohol, and drying in a drying oven after cleaning;

c. cavity heating and vacuum preparation: heating the cavity of the magnetron sputtering instrument to 300 ℃ and vacuumizing the cavity to 3 multiplied by 10 ^-3 Pa；

d. Etching a substrate: performing argon plasma glow etching on the substrate under the conditions of a bias voltage of-250V, an argon flow of 50sccm and an ion source current of 0.15A for 20min;

e. pre-sputtering: argon is introduced into the cavity of the magnetron sputtering instrument, and pre-sputtering is carried out on the Mo target and the Cr target so as to remove oxides or adsorbed impurities on the surface of the target; the pre-sputtering power is 1500W, the vacuum degree is 2.5Pa, and the pre-sputtering time is 10min;

f. sputtering a Mo coating: adjusting the distance between a sample stage and a Mo target, introducing argon, starting a direct-current sputtering power supply, sputtering the Mo target under the conditions of sputtering air pressure of 0.3Pa, bias voltage of-90V, sputtering power of 1300W and deposition temperature of 300 ℃ for 3 hours to obtain a zirconium alloy sample deposited with a Mo coating, and then stopping sputtering; the Mo coating thickness was 4.48 μm.

g. Sputtering Cr coating: adjusting the distance between a sample table and a Cr target, introducing argon and starting a high-power sputtering power supply, sputtering the Cr target under the conditions of sputtering air pressure of 0.3Pa, bias voltage of-80V, pulse frequency of 550Hz, sputtering power of 3500W and deposition temperature of 300 ℃, depositing for 7 hours to obtain a zirconium alloy sample deposited with a Cr/Mo coating, stopping sputtering, keeping the thickness of the Cr coating at 11.02 mu m, and taking out the sample after isothermal reduction to room temperature;

h. and (3) heat treatment: the coating sample was placed in an annealing furnace under high vacuum (vacuum degree 1×10 ^-3 Pa) and annealing at 1000 ℃ for 1h to obtain the multilayer structure protective coating with smooth surface and compact structure.

The total thickness of the protective coating layer of the multilayer structure prepared in this example was found to be 15.85. Mu.m, wherein the thickness of the Mo-Zr layer was 2.41. Mu.m, the thickness of the Cr-Mo layer was 3.32. Mu.m, and the thickness of the Cr layer was 10.12. Mu.m.

Example 3

Example 3 differs from example 1 in that the zirconium alloy substrate of example 3 is not subjected to argon plasma glow etching, and otherwise is the same as example 1.

The total thickness of the protective coating layer of the multilayer structure prepared in this example was found to be 15.32. Mu.m, wherein the thickness of the Mo-Zr layer was 1.43. Mu.m, the thickness of the Cr-Mo layer was 1.92. Mu.m, and the thickness of the Cr layer was 11.97. Mu.m.

Example 4

Comparative example 4 differs from example 1 in that step g of comparative example 4 is: sputtering Cr coating: and adjusting the distance between the sample stage and the Cr target, introducing argon, starting a direct-current sputtering power supply, sputtering the Cr target under the conditions of sputtering air pressure of 0.2Pa, bias voltage of-80V, sputtering power of 3000W and deposition temperature of 200 ℃ for 3.5 hours to obtain a zirconium alloy sample deposited with a Cr/Mo coating, stopping sputtering, keeping the thickness of the Cr coating at 12.41 mu m, and taking out the sample after isothermal reduction to room temperature.

The total thickness of the protective coating layer of the multilayer structure prepared in this example was found to be 15.58. Mu.m, wherein the thickness of the Mo-Zr layer was 1.53. Mu.m, the thickness of the Cr-Mo layer was 2.16. Mu.m, and the thickness of the Cr layer was 11.89. Mu.m.

Comparative example 1:

this comparative example 1 differs from example 1 in that this comparative example 1 only a zirconium alloy workpiece covered with a single layer Cr coating was prepared as follows:

e. pre-sputtering: argon is introduced into the cavity of the magnetron sputtering instrument, and the Cr target is subjected to pre-sputtering to remove oxides or adsorbed impurities on the surface of the target; the pre-sputtering power is 1000W, the vacuum degree is 2.5Pa, and the pre-sputtering time is 15min;

f. sputtering Cr coating: adjusting the distance between the sample stage and the Cr target, introducing argon and starting a high-power sputtering power supply, sputtering the Cr target for 10 hours under the conditions that the sputtering air pressure is 0.2Pa, the bias voltage is-80V, the pulse frequency is 500Hz, the sputtering power is 3000W and the deposition temperature is 200 ℃, obtaining a zirconium alloy sample deposited with a Cr coating, stopping sputtering, and taking out the sample after the isothermal temperature is reduced to room temperature.

Through the steps, the zirconium alloy workpiece with the surface covered with the single-layer Cr coating is finally obtained. The single-layer Cr coating prepared in this comparative example 1 was found to have a thickness of 15.32. Mu.m.

Comparative example 2

Comparative example 2 differs from example 1 in that comparative example 2 is a zirconium alloy substrate surface sputtered with Al ₂ O ₃ The preparation method comprises the following steps:

a. pretreatment of a matrix material: preparing Zirlo zirconium alloy with the size of 15mm multiplied by 10mm multiplied by 2mm, sequentially polishing the surface by using No. 1000, no. 2000 and No. 3000 water sand paper, polishing, ultrasonically cleaning the zirconium alloy for 30min by using acetone alcohol, and drying in a drying oven after cleaning;

c. cavity heating and vacuum preparation: vacuum pumping the cavity of the magnetron sputtering instrument to 3X 10 ^-3 Pa；

e. pre-sputtering: argon is introduced into the cavity of the magnetron sputtering instrument to lead Al to be ₂ O ₃ Pre-sputtering the target material and the Cr target material to remove oxide or adsorption impurities on the surface of the target material; the pre-sputtering power is 1000W, the vacuum degree is 2.5Pa, and the pre-sputtering time is 15min;

f. sputtering Al ₂ O ₃ And (3) coating: adjusting the distance between the sample stage and the Al target, introducing argon and oxygen and openingStarting a direct-current sputtering power supply, sputtering an Al target material under the conditions of sputtering air pressure of 0.2Pa, bias voltage of-80V, sputtering power of 250W and deposition temperature of room temperature, and depositing for 6 hours to obtain the deposited Al ₂ O ₃ A sample of the coated zirconium alloy, followed by stopping sputtering;

g. closing the oxygen and Ar valves, continuing the vacuumizing operation, and waiting for vacuumizing to 3X 10 ^-3 Heating the sample stage after Pa, and setting the temperature to 200 ℃;

h. sputtering Cr coating: adjusting the distance between a sample stage and a Cr target, introducing argon, starting a high-power pulse sputtering power supply, sputtering the Cr target under the conditions of sputtering air pressure of 0.2Pa, bias voltage of-80V, pulse frequency of 500Hz, sputtering power of 3000W and deposition temperature of 200 ℃ for 8 hours to obtain a zirconium alloy sample deposited with a Cr coating, stopping sputtering, keeping the thickness of the Cr coating at 12.17 mu m, and taking out the sample after the vacuum temperature is reduced to room temperature;

i. and (3) heat treatment: the coating sample was placed in an annealing furnace under high vacuum (vacuum degree of 2×10 ^-3 Pa) and annealing at 900 ℃ for 1h.

Through the steps, the zirconium alloy workpiece with the surface covered with the multilayer coating is finally obtained.

Comparative example 3

Comparative example 3 differs from example 1 in that step f of comparative example 3 is:

sputtering a Mo coating: and adjusting the distance between the sample stage and the Mo target material, introducing argon, starting a direct-current sputtering power supply, and sputtering the Mo target material for 15 hours under the conditions of 0.2Pa sputtering air pressure, -80V bias voltage, 1000W sputtering power and 200 ℃ deposition temperature to obtain the Mo coating with the thickness of 16.25 mu m.

The detection shows that the surface of the zirconium alloy matrix forms four layers of structures, namely a Mo-Zr layer, a Mo layer, a Cr-Mo layer and a metal Cr layer.

Steam corrosion test of protective coating

The zirconium alloy substrates, the zirconium alloy workpieces with protective coatings prepared in examples 1-4 and comparative examples 1-3, respectively, were oxidized in a 1200 c water vapor environment for 0.5h at a water vapor flow rate of 1.5g/min. In order to ensure the accuracy of the oxidation weight gain data, the number of oxidation test samples is not less than three under each parameter, and the oxidation weight gain is averaged. Specific test data are shown in Table 1.

TABLE 1

As can be seen from the data in the table, the invention prepares the multilayer structure protective coating on the surface of the Zirlo zirconium alloy, the oxidation weight gain of the multilayer structure protective coating is obviously lower than that of the Zirlo zirconium alloy matrix and a single-layer Cr coating sample, and the multilayer structure protective coating greatly enhances the accident-resistant fault-tolerant capability of the zirconium alloy workpiece. In addition, compared with a single-layer Cr coating sample, the multilayer structure protective coating sample has no obvious Zr-Cr interdiffusion layer in the interior after high-temperature steam corrosion, so that the multilayer structure protective coating can effectively block interdiffusion of two elements, namely Zr and Cr at high temperature.

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

In the preparation method of the invention, the sequence of each step is not limited to the listed sequence, and the sequential change of each step is also within the protection scope of the invention without the inventive labor for the person skilled in the art. Furthermore, two or more steps or actions may be performed simultaneously.

Finally, it should be noted that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention's embodiments. Those skilled in the art may make various modifications or additions to the described embodiments or substitutions in a similar manner, and need not and cannot fully practice all of the embodiments. While these obvious variations and modifications, which come within the spirit of the invention, are within the scope of the invention, they are to be construed as being without departing from the spirit of the invention.

Claims

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:

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.