A gradient coating for lead-cooled fast reactor cladding tube and its preparation method and application

Abstract

The present invention discloses a gradient coating for lead-cooled fast reactor cladding tubes and a preparation method and application thereof, belonging to the technical field of protective coatings. The coating is composed of three layers of coatings, namely, an innermost layer, an intermediate layer and an outermost layer; the innermost layer is composed of a FeCrAlSiTiMo high entropy alloy coating; the intermediate layer is composed of a WNbMoTaTi high entropy alloy; and the outermost layer is composed of a (HfNbTaTiZr)N high entropy ceramic. The present invention can improve the bonding force between the coating and the substrate and between the coatings through a gradient structure design, and alleviate the cracking and peeling problems of the coating during use. In addition, the gradient coating effectively disperses the stress distribution when impacted through its design of gradually increasing hardness from the substrate to the surface, thereby inhibiting the expansion of cracks. This gradient change in hardness allows the coating to maintain a certain toughness in the bottom layer while maintaining a high hardness on the surface, thereby improving the erosion resistance of the coating.

Description

Technical Field

[0001] The invention belongs to the technical field of protective coatings, and in particular relates to a gradient coating for a lead-cooled fast reactor cladding tube, and a preparation method and application thereof. Background Art

[0002] As one of the main candidate reactor types for the fourth-generation nuclear energy system, the lead-cooled fast reactor using liquid lead or lead-bismuth alloy as coolant has the advantages of excellent neutron economy, high thermal efficiency, good chemical stability and inherent safety. Its development and application are of great significance to the sustainable development of nuclear energy.

[0003] However, in lead-cooled fast reactors, the coolant temperature and flow rate are high in the area where the cladding tubes are located. This high-temperature liquid lead or lead-bismuth coolant will firstly produce strong dissolution and oxidation corrosion on the cladding tube material. When the oxygen content in lead or lead-bismuth is high, the elemental components in the cladding tube will dissolve into the coolant, and dissolution corrosion will occur; when the oxygen content in lead or lead-bismuth is high, oxidation corrosion will occur on the surface of the cladding tube. Secondly, the high-flow coolant will also produce strong friction and erosion on the cladding tube. This corrosion and erosion will not only reduce the structural strength of the cladding tube, but also may affect the safe and stable operation of the reactor, and may even cause the leakage of radioactive materials, thus bringing serious nuclear safety problems.

[0004] Therefore, the development of a new protective coating for cladding tubes that is resistant to high-temperature and high-flow rate lead alloy erosion corrosion can not only improve the corrosion resistance of the cladding tubes and extend their service life, but also improve the safety and reliability of the entire reactor system. It has important scientific and engineering application value for promoting the development and application of lead-cooled fast reactor technology. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the above background technology, and to provide a gradient coating for lead-cooled fast reactor cladding tubes, which has good matching with the cladding tube material matrix and good resistance to high-flow lead alloy erosion corrosion, as well as a preparation method and application thereof.

[0006] In order to solve the above technical problems, the technical solution proposed by the present invention is:

[0007] A gradient coating for a lead-cooled fast reactor cladding tube, comprising an innermost layer, an intermediate layer and an outermost layer; the innermost layer is composed of a FeCrAlSiTiMo high entropy alloy coating; the intermediate layer is composed of a WNbMoTaTi high entropy alloy; and the outermost layer is composed of a (HfNbTaTiZr)N high entropy ceramic.

[0008] As a further improvement, the molar ratio of each element in the innermost layer of FeCrAlSiTiMo high entropy alloy is Fe:Cr:Al:Si:Ti:Mo=(0.9~1.1):(0.9~1.1):(0.9~1.1):(0.2~2):(0.9~1.1):(0.9~1.1); the molar ratio of each element in the middle layer of WNbMoTaTi high entropy alloy is W:Nb:Mo:Ta:Ti=(0.9~1.1):(1.8~2.2):(1.8~2.2):(0.9~1.1):(0.9~1.1); the molar ratio of each metal element in the outermost layer of (HfNbTaTiZr)N high entropy ceramic is Hf:Nb:Ta:Ti:Zr=(0.9~1.1):(0.9~1.1):(0.9~1.1):(0.9~1.1).

[0009] As a further improvement, the molar ratio of the elements in the innermost layer of the FeCrAlSiTiMo high entropy alloy is Fe:Cr:Al:Si:Ti:Mo=1:1:1:1:1:1; the molar ratio of the elements in the middle layer of the WNbMoTaTi high entropy alloy is W:Nb:Mo:Ta:Ti=1:2:2:1:1; the molar ratio of the metal elements in the outermost layer of the (HfNbTaTiZr)N high entropy ceramic is Hf:Nb:Ta:Ti:Zr=1:1:1:1:1.

[0010] As a further improvement, the thickness of the innermost coating layer is 10-15 μm, the thickness of the middle coating layer is 15-20 μm, and the thickness of the outermost coating layer is 15-20 μm.

[0011] The present invention provides a method for preparing a gradient coating for a lead-cooled fast reactor cladding tube, comprising the following steps:

[0012] (1) FeCrAlSiTiMo high entropy alloy coating was prepared on the surface of cladding tube by magnetron sputtering;

[0013] (2) The WNbMoTaTi high entropy alloy coating was prepared on the surface of the FeCrAlSiTiMo high entropy alloy coating by magnetron sputtering;

[0014] (3) A (HfNbTaTiZr)N high entropy ceramic coating is prepared on the surface of the WNbMoTaTi high entropy alloy coating by a glow plasma method to obtain the gradient coating.

[0015] As a further improvement, FeCrAlSiTiMo high entropy alloy is prepared by powder metallurgy, and melted and cast into a target material, and then magnetron sputtering is performed in step (1);

[0016] The magnetron sputtering parameters of step (1) are: sputtering power 100~500W, argon gas flow rate 20~50sccm, spraying distance 60~100mm, sputtering pressure 10 -3 ~10 -2 Pa, sputtering time 20~30min.

[0017] As a further improvement, WNbMoTaTi high entropy alloy is prepared by powder metallurgy, and melted and cast into a target material, and then magnetron sputtering is performed in step (2);

[0018] The magnetron sputtering parameters of step (2) are: sputtering power 300~500W, argon gas flow rate 3~5sccm, spraying distance 5~7cm, sputtering pressure 100~150Pa, and sputtering time 20~30min.

[0019] As a further improvement, HfNbTaTiZr metal powder is prepared by powder metallurgy, and then the surface of the WNbMoTaTi high entropy alloy coating is pretreated using a high-current pulsed electron beam before performing step (3).

[0020] As a further improvement, the parameters of the high-current pulse electron beam are: pulse width 2~3μm, pulse frequency 0.1~0.2Hz, electron beam acceleration voltage 21~27kV, irradiation times 12~18 times, irradiation distance 80~120mm;

[0021] The glow plasma method parameters are: radio frequency power 1000-3000W, nitrogen pressure in the chamber 50-500Pa, and spraying time 30-40min.

[0022] The invention provides a lead-cooled fast reactor cladding tube with a coating on the surface, wherein the coating is the gradient coating.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The gradient coating for the lead-cooled fast reactor cladding tube of the present invention adopts a gradient structure and is divided into three layers. The innermost layer has a lower hardness than the middle layer and is composed of a FeCrAlSiTiMo high entropy alloy whose chemical composition and thermal expansion coefficient match the cladding tube matrix. The FeCrAlSiTiMo high entropy alloy is a simple face-centered cubic structure, which enables it to have high thermodynamic and kinetic stability, and the elements in the alloy diffuse slowly, thereby greatly reducing the possibility of dissolution corrosion in liquid lead or lead-bismuth environments; at the same time, the FeCrAlSiTiMo high entropy alloy is easy to form dense protective oxide films such as A2lO3, SiO2 and TiO2 in oxygen-containing liquid lead or lead-bismuth environments, thereby effectively alleviating oxidative corrosion.

[0025] The middle layer is composed of a WNbMoTaTi high entropy alloy whose chemical composition and thermal expansion coefficient match those of the innermost high entropy alloy coating. Compared with the innermost FeCrAlSiTiMo high entropy alloy, the middle layer WNbMoTaTi high entropy alloy also has better resistance to high-temperature liquid lead or lead-bismuth corrosion, and has a higher hardness, playing an intermediate transition role.

[0026] The outermost layer is composed of (HfNbTaTiZr)N high entropy ceramics whose chemical composition and thermal expansion coefficient match those of the intermediate high entropy alloy coating. Compared with the innermost layer and the intermediate layer, (HfNbTaTiZr)N high entropy ceramics have a stronger ability to resist high-temperature dissolution and oxidation corrosion of liquid lead or lead-bismuth due to its ceramic properties; at the same time, (HfNbTaTiZr)N high entropy ceramics have higher hardness and better wear resistance, thus being more resistant to friction and erosion of high-temperature, high-flow liquid lead or lead-bismuth.

[0027] The present invention can effectively alleviate the thermal stress between the coating and the cladding tube substrate and between the coatings through the gradient structure design, improve the bonding force between the coating and the substrate and between the coatings, and alleviate the cracking and peeling problems of the coating during use. In addition, the gradient coating is designed to gradually increase the hardness from the substrate to the surface, which effectively disperses the stress distribution when it is impacted, thereby inhibiting the expansion of cracks. This gradient change in hardness allows the coating to maintain a certain toughness at the bottom layer while maintaining a high hardness on the surface, thereby improving the erosion resistance of the coating.

[0028] At the same time, the coating preparation process provided by the present invention is simple and easy, and can quickly prepare the coating on the lead-cooled fast reactor cladding tube, which is convenient for industrial production. DETAILED DESCRIPTION

[0029] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and carefully in combination with preferred embodiments below, but the protection scope of the present invention is not limited to the following specific embodiments.

[0030] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0031] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0032] In some specific embodiments, the gradient coating for the lead-cooled fast reactor cladding tube of the present invention is composed of three layers of high entropy coating (two layers of high entropy alloy coating and one layer of high entropy ceramic):

[0033] The innermost layer is composed of a FeCrAlSiTiMo high entropy alloy coating, and the molar ratio is preferably Fe:Cr:Al:Si:Ti:Mo=(0.9~1.1):(0.9~1.1):(0.9~1.1):(0.2~2):(0.9~1.1):(0.9~1.1), and the most preferred ratio is 1:1:1:1:1:1. Too high or too low Si content will cause performance degradation;

[0034] The middle layer is composed of WNbMoTaTi high entropy alloy, and the molar ratio is preferably W:Nb:Mo:Ta:Ti=(0.9~1.1):(1.8~2.2):(1.8~2.2):(0.9~1.1):(0.9~1.1), and most preferably 1:2:2:1:1;

[0035] The outermost layer is composed of (HfNbTaTiZr)N high entropy ceramic, and the molar ratio is preferably Hf:Nb:Ta:Ti:Zr=(0.9~1.1):(0.9~1.1):(0.9~1.1):(0.9~1.1):(0.9~1.1), and most preferably 1:1:1:1:1.

[0036] Preferably, the FeCrAlSiTiMo high entropy alloy coating has a thickness of 10 to 15 μm, the WNbMoTaTi high entropy alloy coating has a thickness of 15 to 20 μm, and the (HfNbTaTiZr)N high entropy ceramic coating has a thickness of 15 to 20 μm.

[0037] The present invention adopts a three-layer gradient composite structure, the innermost layer is composed of a FeCrAlSiTiMo high entropy alloy with good corrosion resistance, low hardness, chemical composition and thermal expansion coefficient matching the cladding tube matrix, the middle layer has a higher hardness than the innermost layer, and is composed of a WNbMoTaTi high entropy alloy with a chemical composition and thermal expansion coefficient matching the innermost high entropy alloy coating, and the outermost layer is composed of a (HfNbTaTiZr)N high entropy ceramic with good wear resistance, good erosion resistance, excellent oxidation resistance, and chemical composition and thermal expansion coefficient matching the middle layer high entropy alloy coating.

[0038] In some specific embodiments, the method for preparing the gradient coating for the lead-cooled fast reactor cladding tube of the present invention, the innermost layer and the middle layer are prepared by magnetron sputtering, and the outermost layer is prepared by glow plasma method, and the specific steps are as follows:

[0039] S1. Preparation of high entropy alloy targets and high entropy ceramic metal powders

[0040] ① The innermost layer uses Fe, Cr, Al, Si, Ti, and Mo metals as raw materials for the high entropy alloy coating, and the FeCrAlSiTiMo high entropy alloy is prepared by powder metallurgy according to the above molar ratio, and then melted and cast into a target material;

[0041] ② The intermediate layer uses W, Nb, Mo, Ta, and Ti metals as the raw materials for the high entropy alloy coating. The WNbMoTaTi high entropy alloy is prepared by powder metallurgy according to the above molar ratio, and then melted and cast into a target material.

[0042] ③ According to the above molar ratio, HfNbTaTiZr metal powder is prepared by powder metallurgy.

[0043] S2. Cladding tube matrix preparation

[0044] The cladding tube is cleaned with ultrasonic vibration using deionized water. Optionally, the stains on the surface of the cladding tube that have not been thoroughly cleaned are wiped with an acetone solution. Finally, the cladding tube is placed in an alcohol solution for ultrasonic vibration cleaning.

[0045] The cladding tube matrix is ​​austenitic stainless steel, types include 15-15Ti stainless steel, 316L stainless steel, etc.

[0046] S3. Preparation of high entropy alloy coating

[0047] ① The FeCrAlSiTiMo high entropy alloy coating was prepared on the surface of the prepared cladding tube by magnetron sputtering.

[0048] Specifically, the prepared FeCrAlSiTiMo high entropy alloy target is fixed at the cathode position of the magnetron sputtering device, and sputtering and annealing are performed on the surface of the cladding tube to obtain the FeCrAlSiTiMo high entropy alloy coating. The specific sputtering parameters are: sputtering power 100~500W, argon flow rate 20~50sccm, spraying distance 60~100mm, sputtering pressure 10 -3 ~10 -2 Pa, sputtering time 20~30min.

[0049] ② A magnetron sputtering method is used to prepare an intermediate layer composed of WNbMoTaTi high entropy alloy on the surface of the coating in step ①.

[0050] Specifically, the prepared WNbMoTaTi high entropy alloy target is fixed at the cathode position of the magnetron sputtering device, and sputtering and annealing are performed on the surface of the FeCrAlSiTiMo high entropy alloy coating to obtain the WNbMoTaTi high entropy alloy coating. The specific sputtering parameters are: sputtering power 300~500W, argon flow rate 3~5sccm, spraying distance 5~7cm, sputtering pressure 100~150Pa, and sputtering time 20~30min.

[0051] S4. Preparation of high entropy ceramic coating

[0052] ① Use a high-current pulsed electron beam to pretreat the surface of the WNbMoTaTi high-entropy alloy coating; the parameters of the high-current electron beam are: pulse width 2~3μm, pulse frequency 0.1~0.2Hz, electron beam acceleration voltage 21~27kV, irradiation times 12~18 times, and irradiation distance 80~120mm.

[0053] ② The outermost layer composed of (HfNbTaTiZr)N high entropy ceramic is sprayed on the surface of the WNbMoTaTi high entropy alloy coating by the glow plasma method.

[0054] Specifically, HfNbTaTiZr metal powder is fed into a glow plasma spray gun, nitrogen is selected as the working gas, the glow is kept stable, and the surface of the WNbMoTaTi high entropy alloy coating is sprayed in the glow discharge area to form a (HfNbTaTiZr)N high entropy ceramic coating. The glow plasma method parameters are: RF power 1000~3000W, nitrogen pressure in the chamber 50~500Pa, and spraying time 30~40min.

[0055] In the following embodiments and comparative examples, the same cladding tube is used, and the cladding tube base material is 316L stainless steel.

[0056] Example 1

[0057] S1. Preparation of high entropy alloy targets and high entropy ceramic metal powders

[0058] ① Innermost layer: Fe, Cr, Al, Si, Ti, and Mo metals are selected as the raw materials for the high entropy alloy coating. FeCrAlSiTiMo high entropy alloy is prepared by powder metallurgy according to the molar ratio of Fe:Cr:Al:Si:Ti:Mo=1:1:1:0.2:1:1, and then it is melted and cast into a target material.

[0059] The specific method for preparing the innermost high entropy alloy by powder metallurgy is as follows (the following embodiments are the same): using pure element powders of Fe, Cr, Al, Si, Ti, and Mo with a purity of 99.95% (wt%) as raw materials, and the particle size is less than 20 μm; according to the high entropy alloy composition, each alloy element powder is weighed using an electronic balance with an accuracy of 0.001g; then, the alloy powder is loaded into a stainless steel ball mill, and a high-energy ball mill is used to prepare the high entropy alloy powder; the ball-to-material ratio is 12:1, the rotation speed is 250r / min, the ball milling time is 15h, and finally the high entropy alloy powder is further screened to a particle size of 20~30μm.

[0060] ②Intermediate layer: W, Nb, Mo, Ta, and Ti metals are selected as the raw materials for the high entropy alloy coating. The WNbMoTaTi high entropy alloy is prepared by powder metallurgy according to the molar ratio of W:Nb:Mo:Ta:Ti=1:2:2:1:1, and then it is melted and cast into a target material.

[0061] The specific method for preparing the intermediate layer high entropy alloy by powder metallurgy is as follows (the following embodiments are the same): using pure element powders of W, Nb, Mo, Ta, and Ti with a purity of 99.95% (wt%) as raw materials, and the particle size is less than 20 μm; according to the high entropy alloy composition, each alloy element powder is weighed using an electronic balance with an accuracy of 0.001g; then, the alloy powder is loaded into a stainless steel ball mill, and a high-energy ball mill is used to prepare the high entropy alloy powder; the ball-to-material ratio is 15:1, the rotation speed is 300 r / min, the ball milling time is 15 hours, and finally the high entropy alloy powder is further screened to a particle size of 20~30 μm.

[0062] ③Outermost layer: Prepare HfNbTaTiZr metal powder by powder metallurgy according to the molar ratio of Hf:Nb:Ta:Ti:Zr=1:1:1:1:1.

[0063] The specific method for preparing HfNbTaTiZr alloy powder by powder metallurgy is as follows (the following embodiments are the same): using pure element powders of Hf, Nb, Ta, Ti, and Zr with a purity of 99.95% (wt%) as raw materials, and the particle size is less than 20 μm; according to the metal composition, each metal element powder is weighed using an electronic balance with an accuracy of 0.001g; then, the metal powder is loaded into a stainless steel ball mill, and the alloy powder is prepared using a high-energy ball mill; the ball-to-material ratio is 18:1, the rotation speed is 300 r / min, the ball milling time is 18 hours, and finally the metal powder is further screened to a particle size of 20~30 μm.

[0064] S2. Preparation of lead-cooled fast reactor cladding tube matrix

[0065] Place the cladding tube in deionized water and clean it with ultrasonic vibration for 20 minutes. Then quickly blow dry the cladding tube with a hair dryer. Use acetone solution to repeatedly wipe the stains on the surface of the cladding tube that have not been thoroughly cleaned. Then blow dry it. Finally, place it in an alcohol solution and clean it with ultrasonic vibration for 20 minutes. After taking it out, blow dry it with a hair dryer. The cladding tube substrate is prepared for sputtering coating.

[0066] S3. Preparation of high entropy alloy coating

[0067] Place the treated cladding tube into the vacuum sputtering chamber, place the FeCrAlSiTiMo high entropy alloy target into the target sample stage, seal the vacuum sputtering chamber, evacuate to create a high vacuum environment, and introduce 99.99% high-purity argon gas to prepare the FeCrAlSiTiMo high entropy alloy coating. The specific parameters are: sputtering power 100W, argon flow rate 20sccm, spraying distance 60mm, sputtering pressure 10 -3 Pa, sputtering time 20min.

[0068] The intermediate layer composed of WNbMoTaTi high entropy alloy was prepared on the surface of FeCrAlSiTiMo high entropy alloy coating by magnetron sputtering method. The specific parameters are: sputtering power 300W, argon gas flow rate 3sccm, spraying distance 5cm, sputtering pressure 100Pa, and sputtering time 20min.

[0069] S4. Preparation of high entropy ceramic coating

[0070] The surface of the WNbMoTaTi high entropy alloy coating was pretreated using a high-current pulsed electron beam. The specific parameters were: pulse width 2 μm, pulse frequency 0.1 Hz, electron beam acceleration voltage 21 kV, irradiation times 12 times, and irradiation distance 80 mm.

[0071] The HfNbTaTiZr metal powder was fed into the glow plasma spray gun, nitrogen was selected as the working gas, the glow was kept stable, and the outermost layer composed of (HfNbTaTiZr)N high entropy ceramic was sprayed on the surface of the WNbMoTaTi high entropy alloy coating. The specific parameters were: RF power 1000W, nitrogen pressure in the chamber 50Pa, and spraying time 30min.

[0072] In this embodiment, the total thickness of the gradient coating is 40 μm, the thickness of the innermost coating is 10 μm, and the thickness of the middle layer and the outermost coating is 15 μm.

[0073] Example 2

[0074] S1. Preparation of high entropy alloy targets and high entropy ceramic metal powders

[0075] Innermost layer: Fe, Cr, Al, Si, Ti, and Mo metals are selected as raw materials for the high entropy alloy coating. FeCrAlSiTiMo high entropy alloy is prepared by powder metallurgy according to the molar ratio of Fe:Cr:Al:Si:Ti:Mo=1:1:1:0.5:1:1, and then it is melted and cast into a target material.

[0076] Intermediate layer: W, Nb, Mo, Ta, and Ti metals are selected as raw materials for the high entropy alloy coating. The WNbMoTaTi high entropy alloy is prepared by powder metallurgy according to the molar ratio of W:Nb:Mo:Ta:Ti=1:2:2:1:1, and then it is melted and cast into a target material.

[0077] Outermost layer: HfNbTaTiZr metal powder was prepared by powder metallurgy according to the molar ratio of Hf:Nb:Ta:Ti:Zr=1:1:1:1:1.

[0078] S2. Preparation of lead-cooled fast reactor cladding tube matrix

[0079] Place the cladding tube in deionized water and clean it with ultrasonic vibration for 20 minutes. Then quickly blow dry the cladding tube with a hair dryer. Use acetone solution to repeatedly wipe the stains on the surface of the cladding tube that have not been thoroughly cleaned. Then blow dry it. Finally, place it in an alcohol solution and clean it with ultrasonic vibration for 20 minutes. After taking it out, blow dry it with a hair dryer. The cladding tube substrate is prepared for sputtering coating.

[0080] S3. Preparation of high entropy alloy coating

[0081] Place the treated cladding tube into the vacuum sputtering chamber, place the FeCrAlSiTiMo high entropy alloy target into the target sample stage, seal the vacuum sputtering chamber, evacuate to create a high vacuum environment, and introduce 99.99% high-purity argon gas to prepare the FeCrAlSiTiMo high entropy alloy coating. The specific parameters are: sputtering power 300W, argon flow rate 30sccm, spraying distance 80mm, sputtering pressure 10 -3 Pa, sputtering time 20min.

[0082] The intermediate layer composed of WNbMoTaTi high entropy alloy was prepared on the surface of FeCrAlSiTiMo high entropy alloy coating by magnetron sputtering method. The specific parameters are: sputtering power 400W, argon gas flow rate 4sccm, spraying distance 6cm, sputtering pressure 100Pa, and sputtering time 20min.

[0083] S4. Preparation of high entropy ceramic coating

[0084] The surface of the WNbMoTaTi high entropy alloy coating was pretreated using a high-current pulsed electron beam. The specific parameters were: pulse width 2 μm, pulse frequency 0.1 Hz, electron beam acceleration voltage 24 kV, irradiation times 15 times, and irradiation distance 100 mm.

[0085] The HfNbTaTiZr metal powder was fed into the glow plasma spray gun, nitrogen was selected as the working gas, the glow was kept stable, and the outermost layer composed of (HfNbTaTiZr)N high entropy ceramic was sprayed on the surface of the WNbMoTaTi high entropy alloy coating. The specific parameters were: RF power 2000W, nitrogen pressure in the chamber 300Pa, and spraying time 30min.

[0086] In this embodiment, the total thickness of the gradient coating is 40 μm, the thickness of the innermost coating is 10 μm, and the thickness of the middle layer and the outermost coating is 15 μm.

[0087] Example 3

[0088] S1. Preparation of high entropy alloy targets and high entropy ceramic metal powders

[0089] Innermost layer: Fe, Cr, Al, Si, Ti, and Mo metals are selected as raw materials for the high entropy alloy coating. FeCrAlSiTiMo high entropy alloy is prepared by powder metallurgy according to the molar ratio of Fe:Cr:Al:Si:Ti:Mo=1:1:1:1:1:1, and then it is melted and cast into a target material.

[0090] Intermediate layer: W, Nb, Mo, Ta, and Ti metals are selected as raw materials for the high entropy alloy coating. The WNbMoTaTi high entropy alloy is prepared by powder metallurgy according to the molar ratio of W:Nb:Mo:Ta:Ti=1:2:2:1:1, and then it is melted and cast into a target material.

[0091] Outermost layer: HfNbTaTiZr metal powder was prepared by powder metallurgy according to the molar ratio of Hf:Nb:Ta:Ti:Zr=1:1:1:1:1.

[0092] S2. Preparation of lead-cooled fast reactor cladding tube matrix

[0093] Place the cladding tube in deionized water and clean it with ultrasonic vibration for 20 minutes. Then quickly blow dry the cladding tube with a hair dryer. Use acetone solution to repeatedly wipe the stains on the surface of the cladding tube that have not been thoroughly cleaned. Then blow dry it. Finally, place it in an alcohol solution and clean it with ultrasonic vibration for 20 minutes. After taking it out, blow dry it with a hair dryer. The cladding tube substrate is prepared for sputtering coating.

[0094] S3. Preparation of high entropy alloy coating

[0095] Place the treated cladding tube into the vacuum sputtering chamber, place the FeCrAlSiTiMo high entropy alloy target into the target sample stage, seal the vacuum sputtering chamber, evacuate to create a high vacuum environment, and introduce 99.99% high-purity argon gas to prepare the FeCrAlSiTiMo high entropy alloy coating. The specific parameters are: sputtering power 300W, argon flow rate 30sccm, spraying distance 80mm, sputtering pressure 10 -3 Pa, sputtering time 20min.

[0096] The intermediate layer composed of WNbMoTaTi high entropy alloy was prepared on the surface of FeCrAlSiTiMo high entropy alloy coating by magnetron sputtering method. The specific parameters are: sputtering power 400W, argon gas flow rate 4sccm, spraying distance 6cm, sputtering pressure 100Pa, and sputtering time 20min.

[0097] S4. Preparation of high entropy ceramic coating

[0098] The surface of the WNbMoTaTi high entropy alloy coating was pretreated using a high-current pulsed electron beam. The specific parameters were: pulse width 2 μm, pulse frequency 0.1 Hz, electron beam acceleration voltage 24 kV, irradiation times 15 times, and irradiation distance 100 mm.

[0099] The HfNbTaTiZr metal powder was fed into the glow plasma spray gun, nitrogen was selected as the working gas, the glow was kept stable, and the outermost layer composed of (HfNbTaTiZr)N high entropy ceramic was sprayed on the surface of the WNbMoTaTi high entropy alloy coating. The specific parameters were: RF power 2000W, nitrogen pressure in the chamber 300Pa, and spraying time 30min.

[0100] In this embodiment, the total thickness of the gradient coating is 40 μm, the thickness of the innermost coating is 10 μm, and the thickness of the middle layer and the outermost coating is 15 μm.

[0101] Example 4

[0102] S1. Preparation of high entropy alloy targets and high entropy ceramic metal powders

[0103] Innermost layer: Fe, Cr, Al, Si, Ti, and Mo metals are selected as raw materials for the high entropy alloy coating. FeCrAlSiTiMo high entropy alloy is prepared by powder metallurgy according to the molar ratio of Fe:Cr:Al:Si:Ti:Mo=1:1:1:1.5:1:1, and then it is melted and cast into a target material.

[0104] Intermediate layer: W, Nb, Mo, Ta, and Ti metals are selected as raw materials for the high entropy alloy coating. The WNbMoTaTi high entropy alloy is prepared by powder metallurgy according to the molar ratio of W:Nb:Mo:Ta:Ti=1:2:2:1:1, and then it is melted and cast into a target material.

[0105] Outermost layer: HfNbTaTiZr metal powder was prepared by powder metallurgy according to the molar ratio of Hf:Nb:Ta:Ti:Zr=1:1:1:1:1.

[0106] S2. Preparation of lead-cooled fast reactor cladding tube matrix

[0107] Place the cladding tube in deionized water and clean it with ultrasonic vibration for 20 minutes. Then quickly blow dry the cladding tube with a hair dryer. Use acetone solution to repeatedly wipe the stains on the surface of the cladding tube that have not been thoroughly cleaned. Then blow dry it. Finally, place it in an alcohol solution and clean it with ultrasonic vibration for 20 minutes. After taking it out, blow dry it with a hair dryer. The cladding tube substrate is prepared for sputtering coating.

[0108] S3. Preparation of high entropy alloy coating

[0109] Place the treated cladding tube into the vacuum sputtering chamber, place the FeCrAlSiTiMo high entropy alloy target into the target sample stage, seal the vacuum sputtering chamber, evacuate to create a high vacuum environment, and introduce 99.99% high-purity argon gas to prepare the FeCrAlSiTiMo high entropy alloy coating. The specific parameters are: sputtering power 300W, argon flow rate 30sccm, spraying distance 80mm, sputtering pressure 10 -3 Pa, sputtering time 20min.

[0110] The intermediate layer composed of WNbMoTaTi high entropy alloy was prepared on the surface of FeCrAlSiTiMo high entropy alloy coating by magnetron sputtering method. The specific parameters are: sputtering power 400W, argon gas flow rate 4sccm, spraying distance 6cm, sputtering pressure 100Pa, and sputtering time 20min.

[0111] S4. Preparation of high entropy ceramic coating

[0112] The surface of the WNbMoTaTi high entropy alloy coating was pretreated using a high-current pulsed electron beam. The specific parameters were: pulse width 2 μm, pulse frequency 0.1 Hz, electron beam acceleration voltage 24 kV, irradiation times 15 times, and irradiation distance 100 mm.

[0113] The HfNbTaTiZr metal powder was fed into the glow plasma spray gun, nitrogen was selected as the working gas, the glow was kept stable, and the outermost layer composed of (HfNbTaTiZr)N high entropy ceramic was sprayed on the surface of the WNbMoTaTi high entropy alloy coating. The specific parameters were: RF power 2000W, nitrogen pressure in the chamber 300Pa, and spraying time 30min.

[0114] In this embodiment, the total thickness of the gradient coating is 40 μm, the thickness of the innermost coating is 10 μm, and the thickness of the middle layer and the outermost coating is 15 μm.

[0115] Example 5

[0116] S1. Preparation of high entropy alloy targets and high entropy ceramic metal powders

[0117] Innermost layer: Fe, Cr, Al, Si, Ti, and Mo metals are selected as raw materials for the high entropy alloy coating. FeCrAlSiTiMo high entropy alloy is prepared by powder metallurgy according to the molar ratio of Fe:Cr:Al:Si:Ti:Mo=1:1:1:2:1:1, and then it is melted and cast into a target material.

[0118] Intermediate layer: W, Nb, Mo, Ta, and Ti metals are selected as raw materials for the high entropy alloy coating. The WNbMoTaTi high entropy alloy is prepared by powder metallurgy according to the molar ratio of W:Nb:Mo:Ta:Ti=1:2:2:1:1, and then it is melted and cast into a target material.

[0119] Outermost layer: HfNbTaTiZr metal powder was prepared by powder metallurgy according to the molar ratio of Hf:Nb:Ta:Ti:Zr=1:1:1:1:1.

[0120] S2. Preparation of lead-cooled fast reactor cladding tube matrix

[0121] Place the cladding tube in deionized water and clean it with ultrasonic vibration for 20 minutes. Then quickly blow dry the cladding tube with a hair dryer. Use acetone solution to repeatedly wipe the stains on the surface of the cladding tube that have not been thoroughly cleaned. Then blow dry it. Finally, place it in an alcohol solution and clean it with ultrasonic vibration for 20 minutes. After taking it out, blow dry it with a hair dryer. The cladding tube substrate is prepared for sputtering coating.

[0122] S3. Preparation of high entropy alloy coating

[0123] Place the treated cladding tube into the vacuum sputtering chamber, place the FeCrAlSiTiMo high entropy alloy target into the target sample stage, seal the vacuum sputtering chamber, evacuate to create a high vacuum environment, and introduce 99.99% high-purity argon gas to prepare the FeCrAlSiTiMo high entropy alloy coating. The specific parameters are: sputtering power 500W, argon flow rate 50sccm, spraying distance 100mm, sputtering pressure 10 -3 Pa, sputtering time 20min.

[0124] The intermediate layer composed of WNbMoTaTi high entropy alloy was prepared on the surface of FeCrAlSiTiMo high entropy alloy coating by magnetron sputtering method. The specific parameters are: sputtering power 500W, argon gas flow rate 5sccm, spraying distance 7cm, sputtering pressure 100Pa, and sputtering time 20min.

[0125] S4. Preparation of high entropy ceramic coating

[0126] The surface of the WNbMoTaTi high entropy alloy coating was pretreated using a high-current pulsed electron beam. The specific parameters were: pulse width 3 μm, pulse frequency 0.1 Hz, electron beam acceleration voltage 27 kV, irradiation times 18 times, and irradiation distance 120 mm.

[0127] The HfNbTaTiZr metal powder was fed into the glow plasma spray gun, nitrogen was selected as the working gas, the glow was kept stable, and the outermost layer composed of (HfNbTaTiZr)N high entropy ceramic was sprayed on the surface of the WNbMoTaTi high entropy alloy coating. The specific parameters were: RF power 3000W, nitrogen pressure in the chamber 300Pa, and spraying time 30min.

[0128] Comparative Example 1

[0129] S1. Preparation of high entropy alloy targets

[0130] Fe, Cr, Al, Si, Ti, and Mo metals are selected as raw materials for high entropy alloy coatings. FeCrAlSiTiMo high entropy alloy is prepared by powder metallurgy at a molar ratio of Fe:Cr:Al:Si:Ti:Mo=1:1:1:1:1:1, and then melted and cast into a target material.

[0131] S2. Preparation of lead-cooled fast reactor cladding tube matrix

[0132] Place the cladding tube in deionized water and clean it with ultrasonic vibration for 20 minutes. Then quickly blow dry the cladding tube with a hair dryer. Use acetone solution to repeatedly wipe the stains on the surface of the cladding tube that have not been thoroughly cleaned. Then blow dry it. Finally, place it in an alcohol solution and clean it with ultrasonic vibration for 20 minutes. After taking it out, blow dry it with a hair dryer. The cladding tube substrate is prepared for sputtering coating.

[0133] S3. Preparation of high entropy alloy coating

[0134] Place the treated cladding tube into the vacuum sputtering chamber, place the FeCrAlSiTiMo high entropy alloy target into the target sample stage, seal the vacuum sputtering chamber, evacuate to create a high vacuum environment, and introduce 99.99% high-purity argon gas to prepare the FeCrAlSiTiMo high entropy alloy coating. The specific parameters are: sputtering power 300W, argon flow rate 30sccm, spraying distance 80mm, sputtering pressure 10 -3 Pa, sputtering time 20min.

[0135] In this comparative example, the total coating thickness is 10 μm.

[0136] Comparative Example 2

[0137] S1. Preparation of high entropy alloy targets

[0138] Inner layer: Fe, Cr, Al, Si, Ti, and Mo metals are selected as raw materials for the high entropy alloy coating. FeCrAlSiTiMo high entropy alloy is prepared by powder metallurgy according to the molar ratio of Fe:Cr:Al:Si:Ti:Mo=1:1:1:1:1:1, and then it is melted and cast into a target material.

[0139] Outer layer: W, Nb, Mo, Ta, and Ti metals are selected as raw materials for the high entropy alloy coating. The WNbMoTaTi high entropy alloy is prepared by powder metallurgy according to the molar ratio of W:Nb:Mo:Ta:Ti=1:2:2:1:1, and then it is melted and cast into a target material.

[0140] S2. Preparation of lead-cooled fast reactor cladding tube matrix

[0141] Place the cladding tube in deionized water and clean it with ultrasonic vibration for 20 minutes. Then quickly blow dry the cladding tube with a hair dryer. Use acetone solution to repeatedly wipe the stains on the surface of the cladding tube that have not been thoroughly cleaned. Then blow dry it. Finally, place it in an alcohol solution and clean it with ultrasonic vibration for 20 minutes. After taking it out, blow dry it with a hair dryer. The cladding tube substrate is prepared for sputtering coating.

[0142] S3. Preparation of double-layer high entropy alloy coating

[0143] Place the treated cladding tube into the vacuum sputtering chamber, place the FeCrAlSiTiMo high entropy alloy target into the target sample stage, seal the vacuum sputtering chamber, evacuate to create a high vacuum environment, and introduce 99.99% high-purity argon gas to prepare the FeCrAlSiTiMo high entropy alloy coating. The specific parameters are: sputtering power 300W, argon flow rate 30sccm, spraying distance 80mm, sputtering pressure 10 -3Pa, sputtering time 20min.

[0144] The intermediate layer composed of WNbMoTaTi high entropy alloy was prepared on the surface of FeCrAlSiTiMo high entropy alloy coating by magnetron sputtering method. The specific parameters are: sputtering power 400W, argon gas flow rate 4sccm, spraying distance 6cm, sputtering pressure 100Pa, and sputtering time 20min.

[0145] In this comparative example, the thicknesses of the FeCrAlSiTiMo high entropy alloy coating and the WNbMoTaTi high entropy alloy coating are 10 μm and 15 μm, respectively.

[0146] Performance test of the gradient coating for lead-cooled fast reactor cladding tube in the above examples and comparative examples:

[0147] The gradient coating's anti-lead alloy erosion corrosion performance test was carried out using a liquid metal rotary corrosion device. During the test, the temperature of the liquid metal (lead-bismuth) on the coating surface was 550°C, the flow rate of the liquid metal was 0.27m / s, and the corrosion time was 1500h. The test results are shown in Table 1.

[0148] Table 1

[0149]

[0150] The results show that the corrosion weight loss of the 316L sample coated with the gradient coating is significantly lower than that of the uncoated sample and the control sample, indicating that the gradient coating can effectively improve the lead-bismuth erosion corrosion resistance of the 316L sample.

[0151] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Therefore, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for preparing a gradient coating for a lead-cooled fast reactor cladding tube, characterized in that: The steps include: (1) The FeCrAlSiTiMo high entropy alloy coating was prepared on the surface of the cladding tube by magnetron sputtering. The magnetron sputtering parameters were: sputtering power 100~500W, argon flow rate 20~50sccm, spraying distance 60~100mm, sputtering pressure 10 -3 ~10 -2 Pa, sputtering time 20~30min; (2) The WNbMoTaTi high entropy alloy coating was prepared on the surface of the FeCrAlSiTiMo high entropy alloy coating by magnetron sputtering. The magnetron sputtering parameters were: sputtering power 300~500W, argon flow rate 3~5sccm, spraying distance 5~7cm, sputtering pressure 100~150Pa, and sputtering time 20~30min. (3) preparing a (HfNbTaTiZr)N high entropy ceramic coating on the surface of the WNbMoTaTi high entropy alloy coating by a glow plasma method to obtain the gradient coating; The parameters of the glow plasma method are: RF power 1000~3000W, nitrogen pressure in the chamber 50~500Pa, spraying time 30~40min; The gradient coating is composed of three layers: an innermost layer, an intermediate layer and an outermost layer; the innermost layer is composed of a FeCrAlSiTiMo high entropy alloy coating; the intermediate layer is composed of a WNbMoTaTi high entropy alloy; and the outermost layer is composed of a (HfNbTaTiZr)N high entropy ceramic. The molar ratio of each element in the innermost layer of FeCrAlSiTiMo high entropy alloy is Fe:Cr:Al:Si:Ti:Mo=(0.9~1.1):(0.9~1.1):(0.9~1.1):(0.2~2):(0.9~1.1):(0.9~1.1); the molar ratio of each element in the middle layer of WNbMoTaTi high entropy alloy is W:Nb:Mo:Ta:Ti=(0.9~1.1):(1.8~2.2):(1.8~2.2):(0.9~1.1):(0.9~1.1); the molar ratio of each metal element in the outermost layer of (HfNbTaTiZr)N high entropy ceramic is Hf:Nb:Ta:Ti:Zr=(0.9~1.1):(0.9~1.1):(0.9~1.1):(0.9~1.1).

2. The method for preparing a gradient coating for a lead-cooled fast reactor cladding tube according to claim 1, characterized in that: The molar ratio of each element of the FeCrAlSiTiMo high entropy alloy in the innermost layer is Fe:Cr:Al:Si:Ti:Mo=1:1:1:1:1:1; the molar ratio of each element of the WNbMoTaTi high entropy alloy in the middle layer is W:Nb:Mo:Ta:Ti=1:2:2:1:1; the molar ratio of each metal element of the (HfNbTaTiZr)N high entropy ceramic in the outermost layer is Hf:Nb:Ta:Ti:Zr=1:1:1:1:

1.

3. The method for preparing a gradient coating for a lead-cooled fast reactor cladding tube according to claim 1 or 2, characterized in that: The thickness of the innermost coating layer is 10-15 μm, the thickness of the middle coating layer is 15-20 μm, and the thickness of the outermost coating layer is 15-20 μm.

4. The method for preparing a gradient coating for a lead-cooled fast reactor cladding tube according to claim 1, characterized in that: The FeCrAlSiTiMo high entropy alloy is prepared by powder metallurgy, melted and cast into a target material, and then magnetron sputtering is performed in step (1).

5. The method for preparing a gradient coating for a lead-cooled fast reactor cladding tube according to claim 1 or 4, characterized in that: The WNbMoTaTi high entropy alloy is prepared by powder metallurgy, melted and cast into a target material, and then magnetron sputtering is performed in step (2).

6. The method for preparing a gradient coating for a lead-cooled fast reactor cladding tube according to claim 1 or 4, characterized in that: The HfNbTaTiZr metal powder is prepared by powder metallurgy, and then the surface of the WNbMoTaTi high entropy alloy coating is pretreated using a high-current pulsed electron beam, and then step (3) is performed.

7. The method for preparing a gradient coating for a lead-cooled fast reactor cladding tube according to claim 6, characterized in that: The parameters of the high-current pulse electron beam are: pulse width 2-3 μm, pulse frequency 0.1-0.2 Hz, electron beam acceleration voltage 21-27 kV, irradiation times 12-18 times, and irradiation distance 80-120 mm.

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