A method for preparing a metal nitride MN (M=Al or Cr) / oxide M'2O3 (M'=Al, Y or Er) composite ceramic tritium permeation barrier coating

Abstract

The application discloses a preparation method of a metal nitride MN (M=Al or Cr) / oxide M'2O3 (M'=Al, Y or Er) composite ceramic anti-erosion tritium-resistant coating and belongs to the technical field of coatings. The metal nitride MN (M=Al or Cr) / oxide M'2O3 (M'=Al, Y or Er) composite ceramic anti-erosion tritium-resistant coating is prepared by the following steps: firstly, surface treatment is performed on a substrate by a metal organic decomposition method; then, a prepared metal nitride MN (M=Al or Cr) coating precursor substrate is immersed and pulled up; after drying in an air atmosphere, the metal nitride MN (M=Al or Cr) coating precursor substrate is annealed and sintered in a nitrogen atmosphere to form a metal nitride MN (M=Al or Cr) / oxide M'2O3 (M'=Al, Y or Er) composite anti-erosion tritium-resistant coating. The metal nitride MN (M=Al or Cr) / oxide M'2O3 (M'=Al, Y or Er) composite anti-erosion tritium-resistant coating has the advantages of low tritium permeability, corrosion resistance to liquid lithium alloy, low cost, good compactness, controllable thickness, strong film-substrate adhesion, no easy cracking, no limitation on the size of a workpiece and the like.

Description

Technical Field

[0001] This invention belongs to the field of nuclear functional ceramic materials technology, and relates to a method for preparing a metal nitride MN (M = Al or Cr) / oxide M'2O3 (M' = Al, Y or Er) composite ceramic anti-corrosion and tritium-inhibiting coating. The method is for preparing a metal nitride MN (M = Al or Cr) / oxide M'2O3 (M' = Al, Y or Er) composite anti-corrosion and tritium-inhibiting coating on the fusion reactor blanket structure material. Background Technology

[0002] Low-activation ferritic / martensitic steel (RAFM) is a leading candidate structural material for the blanket modules of future fusion reactors. The primary function of the blanket is to generate fusion tritium fuel, providing sustained high-temperature plasma for the fusion reactor, thus achieving tritium self-sufficiency. However, tritium, as a small molecule, is easily lost through permeation into structural materials, causing radioactive hazards to the environment and leading to material embrittlement. Therefore, a tritium permeation barrier (TPB) must be prepared on the structural material. Common corrosion-resistant and tritium-inhibiting coatings mainly include metal oxides (Al2O3, Cr2O3, Y2O3, ZrO2, and Er2O3, etc.), nitrides (Fe2N, TiN), carbides (TiC, SiC, etc.), and their composites. Different types of corrosion-resistant and tritium-inhibiting coatings have their own advantages and disadvantages. Al2O3 coatings have a high tritium barrier factor (>10). 4 Al2O3 coatings, with their mature component-level fabrication processes and certain self-healing capabilities (Al coatings can spontaneously form a stable Al2O3 passivation film with oxygen), have become the mainstream tritium-blocking coatings, suitable for Li4SiO4 / Li2TiO3 solid spherical bed cladding and tritium external circulation components. Besides Al2O3 coatings, rare earth oxide coatings such as M'2O3 (M = Y, Er) not only possess excellent tritium-blocking properties but also exhibit good compatibility with the more corrosive liquid lithium-lead alloys in liquid tritium breeding claddings, making them highly sought after.

[0003] Er₂O₃ coatings, as rare earth oxides, are also recognized as one of the candidate materials for TPB (transfer-to-phosphorus boron). Er₂O₃ has a cubic crystal structure with a lattice constant of 1.05 nm and a relatively stable crystal structure below 2300℃. Er₂O₃ coatings can be prepared at relatively low temperatures, exhibit good compatibility with liquid Li-Pb, and maintain good electrical insulation properties even under neutron irradiation. Simultaneously, Er₂O₃ also possesses excellent hydrogen barrier properties; a coating approximately 1 μm thick can improve the hydrogen barrier performance of the substrate by 1000 times. However, on the other hand, the adhesion between the Er₂O₃ coating and the structural material is poor. Furthermore, thermal expansion leading to thermal mismatch with the structural material and poor thermal shock resistance can cause stress release, making stress concentration points more prone to cracking or micropores.

[0004] AlN coatings possess advantages such as high stability, high thermal resistivity, excellent radiation resistance, and low manufacturing cost. AlN has a hexagonal crystal structure, with Al and N atoms connected by stable covalent bonds. This results in a much higher activation energy for the dissociation and diffusion of tritium in AlN compared to metallic materials, thus providing tritium blocking properties. Furthermore, due to its hexagonal crystal structure, its thermal expansion characteristics are similar to those of metal substrates, and its thermal conductivity is relatively high among ceramics, effectively reducing thermal stress between the ceramic coating and the metal substrate and improving film-substrate adhesion. However, the hydrolysis reaction of AlN poses serious problems for storage and processing. When stored in an air atmosphere at room temperature and pressure, AlN is easily exposed to moisture, leading to a hydrolysis reaction on its surface. During AlN hydrolysis, amorphous AlOOH first appears on the crystal surface, then gradually transforms into Al(OH)3. Finally, the generated Al(OH)3 grows on the AlN crystal surface, forming a protective layer that encapsulates the AlN crystal. When AlN is hydrolyzed by water, the oxygen content increases, which in turn reduces the thermal conductivity of AlN ceramics.

[0005] Currently, the main methods for preparing metal nitride / oxide coatings include hot-dip galvanizing (HDA), electrodeposition (ECD), chemical vapor deposition (CVD), and magnetron sputtering. These methods typically involve two steps: first, depositing the appropriate reactive metal (Al, Cr, Y, or Er), and then generating an in-situ MN (M = Cr, Al) or M'₂O₃ (M = Al, Y, Er) coating through heat treatment under different atmospheres. However, these methods have limitations, such as complex equipment and toxic byproducts, particularly poor coating performance on complex-shaped surfaces of cladding structures or complex-shaped internal surfaces of tubes and chambers. Therefore, there is an urgent need to develop new preparation methods and improve existing technologies to prepare metal nitride / oxide (TPB) coatings.

[0006] Sol-gel technology is attracting attention due to its versatility, simple process equipment, low-temperature synthesis, cost-effectiveness, and controllable coating composition and microstructure. However, sol-gel ceramic coatings are prone to cracking and porosity during drying and heat treatment due to internal stress. Hydrogen / tritium molecules can more easily penetrate these cracks to reach the underlying matrix, thereby reducing the coating's tritium barrier properties. Therefore, the sol-gel method is a challenging task, which may limit its widespread application in TPB coating preparation. Summary of the Invention

[0007] To address the above shortcomings, this invention proposes an improved sol-gel technique, namely metal-organic decomposition (MOD), to prepare a smooth, crack-free metal nitride MN (M = Al or Cr) / oxide M'₂O₃ (M' = Al, Y, or Er) composite ceramic corrosion-resistant tritium-inhibiting coating (TPB coating) on ​​fusion reactor structural steel. The MOD precursor is a viscous liquid formed by dissolving organic acid salts and additives in an organic solvent. Compared to the sol-gel technique, the initial carboxylate in the MOD process is insensitive to water and does not cause aggregation reactions, making the coating less prone to shrinkage or cracking. Therefore, it has significant advantages such as low cost, good density, controllable thickness, strong adhesion to the substrate, resistance to cracking, no limitation on workpiece size, and the ability to be prepared on the surface of large and complex-shaped workpieces.

[0008] This composite ceramic anti-tritium coating possesses both tritium penetration resistance and liquid lead-lithium corrosion resistance, as well as high insulation performance, solving the problem of difficult coating on the surface of complex structural components in fusion reactors.

[0009] The technical problem solved by this invention is to combine the advantages of metal nitride and metal oxide coatings, compensating for their respective shortcomings, to prepare a composite anti-corrosion and tritium-blocking coating of metal nitride MN (M = Al, Cr) / oxide M'2O3 (M = Al, Y, Er). This composite tritium-blocking coating can further provide better protection and durability to the substrate. The two coatings complement each other, increasing the surface's tritium-blocking performance and corrosion resistance.

[0010] The technical solution adopted in this invention is as follows:

[0011] A method for preparing a metal nitride MN (M = Al or Cr) / oxide M'2O3 (M' = Al, Y or Er) composite ceramic corrosion-resistant and tritium-inhibiting coating includes the following steps:

[0012] (1) Substrate surface treatment

[0013] The substrate was first ground and polished with SiC sandpaper and diamond slurry, and then ultrasonically cleaned at room temperature. The cleaning process was carried out in the following order: the polished substrate was first placed in sodium hydroxide solution, then cleaned with ethanol and acetone, and finally soaked in deionized water. The cleaned substrate was then dried in a drying oven.

[0014] (2) Preparation of precursor solutions of metal nitride MN (M = Al, Cr) and metal oxide M'2O3 (M' = Al, Y or Er)

[0015] Take aluminum chloride hexahydrate (or chromium chloride hexahydrate) and urea, dissolve them in anhydrous methanol, heat and stir the solution to obtain a metal nitride MN (M = Al or Cr) precursor for coating.

[0016] Metal M' salts were weighed and dissolved in a mixed solution of n-butyl acetate and ethylene glycol monomethyl ether. After heating and stirring the solution, ethyl acetate, turpentine oil and diethanolamine were added as stabilizers. Finally, rosin and propionic acid were added as film-forming promoters to prepare a metal oxide M'2O3 (M' = Al, Y or Er) precursor for coating.

[0017] (3) Coating

[0018] First, select the metal nitride MN (M = Al or Cr) precursor solution and apply a coating film using the dip-coating method;

[0019] (4) Drying of metal nitride MN (M = Al or Cr) ceramic anti-corrosion and tritium-inhibiting coating

[0020] The coated substrate is first placed in an air atmosphere to keep it warm and dry the easily volatile solvents;

[0021] (5) Sintering and forming of metal nitride MN (M = Al or Cr) ceramic anti-corrosion and tritium-inhibiting coating

[0022] The substrate after the coating is dried is heated to 800-1000℃ under a nitrogen atmosphere and sintered to obtain a metal nitride MN (M=Al or Cr) ceramic anti-corrosion and tritium barrier coating.

[0023] (6) Preparation of composite coating

[0024] Select the aforementioned metal oxide M'2O3 (M = Al, Y or Er) precursor solution and prepare a composite coating on the previously coated sample using the dip-coating method;

[0025] (7) Drying of metal nitride MN (M = Al or Cr) / oxide M'2O3 (M = Al, Y or Er) composite ceramic corrosion-resistant and tritium-inhibiting coating

[0026] After coating, the sample is first kept in an air atmosphere at 80-120℃ for 15-60 minutes to dry the volatile solvent, and then kept in an air atmosphere at 400-480℃ for 15-120 minutes to dry the non-volatile organic solvent.

[0027] (8) Sintering and forming of metal nitride MN (M = Al or Cr) / oxide M'2O3 (M' = Al, Y or Er) composite ceramic anti-corrosion and tritium-inhibiting coating

[0028] The dried coating sample was heated to 480–800℃ in air or argon atmosphere and sintered for 0.5–3 hours to obtain a metal nitride MN (M = Al or Cr) / oxide M'2O3 (M' = Al, Y or Er) composite ceramic anti-corrosion and tritium barrier coating.

[0029] Furthermore, the source of M' (M' = Al, Y, Er) is a compound containing M', including but not limited to M'Cl3·6H2O (M' = Al or Cr), (CH3COO)3M' (M' = Al, Y, or Er), M'(NO3)3 (M' = Al, Y, Er, or Cr), etc.

[0030] Furthermore, the matrix material is 316L stainless steel, low-activation ferritic / martensitic steel, or high-Cr martensitic steel.

[0031] Furthermore, the precursor material of metal oxide M'2O3 (M' = Al, Y or Er) obtained in step (2) is subjected to sample analysis. The sample analysis includes: grinding the sintered metal oxide M'2O3 (M' = Al, Y or Er) ceramic and determining its crystal structure and elemental composition to further determine the precursor (M' = Al, Y or Er) content.

[0032] Furthermore, the sample analysis also includes: the composition of the metal oxide M'2O3 (M = Al, Y, Er) ceramic is scanned using an X-ray diffractometer.

[0033] Furthermore, the content of M' (M' = Al, Y or Er) in the metal oxide M'2O3 (M' = Al, Y or Er) precursor is 2 to 6 wt%, for example, 2 wt%, 2.2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, 5 wt%, 5.5 wt%, 5.8 wt% or 6 wt%.

[0034] Further, in step 2), the molar ratio of aluminum chloride hexahydrate (or chromium chloride hexahydrate) to urea is 1:4 to 1:8. The solution is heated and stirred at 60°C for 10 to 20 minutes. The ratio of the mixed solution of n-butyl acetate and ethylene glycol monomethyl ether is 1:2 to 2:1. The solution is heated and stirred at 100 to 120°C for 60 to 120 minutes.

[0035] Furthermore, in the mixed solution, the propionic acid content is 1-10 wt%, the turpentine content is 10-20 wt%, the ethyl acetate content is 3-13 wt%, the rosin content is 0.1-10 wt%, and the diethanolamine volume fraction is 4-10%.

[0036] Furthermore, in step (3), the immersion and lifting speed is 1 mm·s. -1 The coating thickness is adjusted by repeatedly dipping and pulling, drying, and then dipping and pulling again.

[0037] Furthermore, in steps (4), (5), (7), and (8), the heating rate is 3–6 °C / min. -1 .

[0038] The advantages of this invention compared to existing technologies are as follows: The first AlN / CrN coating can serve as a base layer. Due to its high thermal conductivity and coefficient of thermal expansion, it is close to that of the outer oxide coating M'2O3 (M' = Al, Y, or Er), enhancing the film-substrate adhesion between the oxide coating and the metal substrate. This acts as a bridge between the two layers, effectively alleviating the thermal mismatch problem of the coating and reducing cracks and pores caused by thermal stress concentration. On the other hand, the outer oxide coating can act as a barrier against moisture, preventing hydrolysis of AlN / CrN during storage and transportation. Simultaneously, the high electrical resistance of AlN and Er2O3 gives the composite coating excellent insulation capabilities, effectively reducing the magnetohydrodynamic (MHD) effect of liquid metals under high-intensity magnetic fields.

[0039] This invention employs a metal-organic decomposition method to prepare a metal nitride MN (M = Al or Cr) / oxide M'₂O₃ (M' = Al, Y, or Er) composite ceramic anti-corrosion and tritium-inhibiting coating. Compared to sputtering technology, this invention does not require an expensive vacuum system and is not limited by workpiece size, allowing the preparation of metal nitride MN (M = Al or Cr) / oxide M'₂O₃ (M' = Al, Y, or Er) composite ceramic anti-corrosion and tritium-inhibiting coatings on the surface of large and complex-shaped workpieces. Compared to the sol-gel method, the initial carboxylates in the metal-organic decomposition process are not sensitive to water and do not cause aggregation reactions. Therefore, the coating is less prone to shrinkage or cracking. Attached Figure Description

[0040] Figure 1 Preparation process diagram of metal nitride MN (M = Al, Cr) / oxide M'2O3 (M' = Al, Y or Er) anti-corrosion and tritium-inhibiting coating;

[0041] Figure 2 The surface morphology and elemental distribution of the erbium oxide coating after sintering at 600℃ are shown in the diagram.

[0042] Figure 3 The TG-DSC curve of the precursor with Er content of 3wt% is shown. Detailed Implementation

[0043] The following will clearly and completely describe the concept and technical effects of the present invention with reference to embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0044] like Figure 1 As shown, a method for preparing a metal nitride MN (M = Al or Cr) / oxide M'2O3 (M' = Al, Y or Er) composite ceramic corrosion-resistant and tritium-inhibiting coating includes the following steps:

[0045] S1: Substrate surface treatment

[0046] The substrate material was first polished using SiC abrasive paper (400#, 600#, 800#, 1200#, and 1800# in sequence) and diamond slurry on an automatic grinding machine, followed by ultrasonic cleaning at room temperature. The cleaning process was carried out in the following order: the polished substrate was first placed in a 10wt% sodium hydroxide solution, then cleaned with ethanol and acetone, and finally soaked in deionized water for 20 minutes before being dried in a drying oven.

[0047] S2: Preparation of precursor solution

[0048] Prepare MCl3·6H2O (M = Al or Cr), urea, methanol, (CH3COO)3M' (M' = Al, Y or Er), n-butyl acetate, ethylene glycolamine, ethylene glycol monomethyl ether, ethyl acetate, turpentine, propionic acid, and rosin.

[0049] Preparation of the metal nitride MN (M = Al or Cr) precursor: Weigh an appropriate amount of aluminum chloride hexahydrate (or chromium chloride hexahydrate) and urea and dissolve them in 10 ml of anhydrous methanol. The molar ratio of the metal chloride to urea is 1:4 to 1:8. Stir the solution at a constant temperature of 50°C for 20 min with a magnetic stirrer until the solution turns completely milky white.

[0050] Preparation of metal oxide M'₂O₃ (M' = Al, Y, or Er) precursors: Weigh an appropriate amount of erbium acetate (or yttrium acetate, aluminum acetate) and dissolve it in a mixed solution of n-butyl acetate and ethylene glycol monomethyl ether to prepare precursor solutions with different metal ion contents. The ratio of n-butyl acetate to ethylene glycol monomethyl ether mixed solutions is 1:2 to 2:1, and the metal ion content in the precursor is 2 to 5 wt%. Place the solution in a magnetically stirred heating mantle and heat to 100–120 °C, stirring for 60–120 min. After the solution boils, add an appropriate amount of ethyl acetate and diethanolamine as stabilizers. The volume fraction of diethanolamine is 4–10%, and the content of ethyl acetate is 3–13 wt%. Stir until the solution becomes completely clear and transparent. Then add an appropriate amount of rosin, propionic acid, and turpentine as film-forming promoters until the solution becomes a dark brown MOD precursor, which is then stored for later use. The content of propionic acid is 1-10 wt%, the content of turpentine is 10-20 wt%, and the content of rosin is 0.1-10 wt%.

[0051] S3: Coating

[0052] The metal nitride MN (M = Al or Cr) precursor solution was coated using a dip-coating method. The dip-coating and lifting speeds were 1 mm / s. -1 The coating thickness is adjusted by repeatedly dipping and pulling, drying, and then dipping and pulling again.

[0053] S4: Drying of metal nitride MN (M = Al, Cr) ceramic anti-corrosion and tritium-inhibiting coating

[0054] The coated substrate was first placed in a drying oven at 60℃ for 300 min, with a heating rate of 3-6℃·min. -1 .

[0055] S5: Sintering and forming of metal nitride MN (M = Al or Cr) ceramic anti-corrosion and tritium-inhibiting coating

[0056] The dried substrate was heated to 800–1000 °C in an annealing furnace under a nitrogen atmosphere and calcined for 6 hours to obtain a metal nitride MN (M = Al or Cr) ceramic anti-corrosion and tritium-inhibiting coating. The heating rate of the muffle furnace was 3–6 °C·min. -1 .

[0057] S6: Preparation of Composite Coating

[0058] The metal oxide M'2O3 (M' = Al, Y, or Er) precursor solution was coated using a dip-coating method. The dip-coating and lifting speeds were 1 mm / s. -1 The coating thickness is adjusted by repeatedly dipping and pulling, drying, and then dipping and pulling again.

[0059] S7: Drying of a metal nitride MN (M = Al or Cr) / oxide M'2O3 (M' = Al, Y, or Er) composite ceramic anti-corrosion and tritium-inhibiting coating

[0060] The coated sample was first placed in a forced-air drying oven at 80–120℃ for 15–60 min to dry the volatile solvents. Then it was placed in a muffle furnace at 400–480℃ for 15–120 min to dry the non-volatile organic solvents. The heating rate of the muffle furnace was 3–6℃·min. -1 .

[0061] S8: Sintering and forming of a metal nitride MN (M = Al or Cr) / oxide M'2O3 (M' = Al, Y or Er) composite ceramic corrosion-resistant and tritium-inhibiting coating

[0062] The dried substrate is heated to 480–800 °C in an annealing furnace under an air or argon atmosphere and sintered for 0.5–3 h to obtain a metal nitride MN (M = Al or Cr) / oxide M'₂O₃ (M' = Al, Y, or Er) composite ceramic anti-corrosion and tritium-inhibiting coating. The muffle furnace heating rate is 3–6 °C·min. -1 .

[0063] S9: Performance testing of metal nitride MN (M = Al or Cr) / oxide M'2O3 (M' = Al, Y or Er) composite ceramic corrosion-resistant and tritium-inhibiting coating

[0064] After sintering, the surface, cross-sectional morphology, phase composition, and thickness of the coating were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The coated samples were placed in a muffle furnace and heated to 600℃ at a heating rate of 10℃·min under air atmosphere and room temperature. -1 The coating was removed and quickly immersed in room temperature deionized water, cooled, and then removed and dried. After repeating this process 50 times, the cross-sectional morphology of the coating was observed using a scanning electron microscope. The number of internal cracks and pores in the coating was used to evaluate the service performance stability of the coating under high temperature conditions.

[0065] In step S1, the base material is 316L stainless steel, low-activation ferritic / martensitic steel, or high-Cr martensitic steel.

[0066] In step S4, thermogravimetric / differential thermal analysis (TG–DTA) is used to monitor the change in sample weight with temperature during heating and the pyrolysis spectrum of the weight change process. The heating rate during sintering is 5–6 °C·min. -1 .

[0067] Example 1

[0068] This embodiment provides a method for preparing an AlN / Er2O3 composite corrosion-resistant and tritium-inhibiting coating, using low-activation ferritic / martensitic steel (RAFM) as the substrate. The specific implementation steps are as follows:

[0069] (1) Surface treatment of the substrate. The substrate material was first polished on an automatic grinding machine using SiC sandpaper (400#, 600#, 800#, 1200#, 1800# in sequence) and diamond slurry, and then ultrasonically cleaned at room temperature. The cleaning process was carried out in the following order: the polished substrate was first placed in a 10% sodium hydroxide solution, then cleaned with ethanol and acetone, and finally soaked in deionized water for 20 minutes. The cleaned substrate was then dried in a drying oven.

[0070] (2) Preparation of precursor solution.

[0071] Preparation of aluminum nitride precursor: Prepare analytical grade (AR) aluminum chloride hexahydrate, urea, and anhydrous methanol. Weigh 1.2 g of aluminum chloride hexahydrate and 1.8 g of urea and dissolve them in 10 ml of anhydrous methanol. Stir the solution at a constant temperature of 50 °C with a magnetic stirrer for 20 min until the solution turns completely milky white, becoming the precursor.

[0072] Preparation of erbium oxide precursor: Prepare analytical grade (AR) erbium acetate tetrahydrate, n-butyl acetate, ethylene glycolamine, ethylene glycol monomethyl ether, ethyl acetate, turpentine oil, propionic acid, and rosin. Weigh 3g of erbium acetate tetrahydrate and dissolve it in a mixed solution of 25ml n-butyl acetate and 25ml ethylene glycol monomethyl ether to prepare the precursor solution. Place the solution in a magnetically stirred heating mantle and heat to 120℃ for 60min. After the solution boils, add 10ml ethyl acetate and 2ml diethanolamine as stabilizers, and stir until the solution becomes completely clear and transparent. Then add 2g rosin, 2ml propionic acid, and 5ml turpentine oil as film-forming promoters until the solution becomes a dark brown MOD erbium oxide precursor, which is then stored for later use.

[0073] (3) Precursor Coating. The aluminum nitride precursor solution is coated using a dip-coating method. The substrate is first dip-coated at a speed of 1 mm / s. -1 Immerse the precursor at a rate of 1 mm / s until the matrix is ​​completely submerged. Hold for 5 minutes, then immerse at a rate of 1 mm / s. -1 The pulling speed is used to pull the substrate out of the precursor. During immersion and pulling, the substrate is kept perpendicular to the liquid surface to maintain liquid stability.

[0074] (4) Drying of the aluminum nitride anti-corrosion and tritium-inhibiting coating. The RAFM steel substrate containing the precursor was dried in air at 60°C for 300 min, and organic matter was evaporated separately. The muffle furnace heating rate was 5°C·min. -1 .

[0075] (5) Sintering and forming of aluminum nitride anti-corrosion and tritium-inhibiting coating. The dried substrate was calcined in an annealing furnace at 1000℃ for 6 hours under a nitrogen atmosphere. The nitrogen flow rate was precisely controlled to be 300 sccm (300 mL·min under standard conditions) using a gas flow meter. -1 The heating and cooling rates are both 3℃·min. -1 .

[0076] (6) Preparation of composite coating. The erbium oxide precursor solution was coated using the dip-coating method. The sample was first dipped at a speed of 1 mm·s. -1 Immerse the sample in the precursor at a rate of 1 mm / s until the sample is completely submerged. Hold for 5 minutes, then immerse in the precursor at a rate of 1 mm / s. -1 The pulling speed is used to pull the substrate out of the precursor. During immersion and pulling, the substrate is kept perpendicular to the liquid surface to maintain liquid stability.

[0077] (7) Drying of the aluminum nitride / erbium oxide composite ceramic anti-corrosion and tritium-inhibiting coating. Drying was performed in air at 120℃ and 470℃ for 15 min to evaporate low-melting-point and high-melting-point organic compounds, respectively. The muffle furnace heating rate was 5℃·min. -1 .

[0078] (8) Sintering and forming of aluminum nitride / erbium oxide composite ceramic anti-corrosion and tritium-inhibiting coating. The dried sample was heated to 700℃ in an annealing furnace under air or argon atmosphere and sintered for 1 h to obtain the aluminum nitride / erbium oxide composite ceramic anti-corrosion and tritium-inhibiting coating. The muffle furnace heating rate was 5℃·min. -1 .

[0079] Figure 1 This is a process diagram for preparing a metal nitride MN (M = Al, Cr) / oxide M'2O3 (M' = Al, Y or Er) anti-corrosion and tritium-inhibiting coating.

[0080] Figure 2 The image shows the surface morphology and elemental distribution of the erbium oxide coating after sintering at 600℃. As can be seen from the image, the coating prepared by this method has a smooth and flat surface, without any cracks or pores. The Er element is uniformly distributed, with a relative content of 75.51 wt%.

[0081] Figure 3 The figure shows the TG-DSC curve of the precursor with an Er content of 3 wt%. As can be seen from the figure, the process of MOD precursor decomposition to form the coating mainly includes solvent evaporation, volatilization and reaction of macromolecules, and decomposition of organometallic compounds. Furthermore, the evaporation and decomposition stages are accompanied by hydrolysis and crystallization processes, respectively. After reaching 510℃, the precursor is completely converted to Er₂O₃ and its mass no longer changes.

[0082] Example 2

[0083] This embodiment provides a method for preparing a CrN / Er2O3 corrosion-resistant and tritium-inhibiting coating, using low-activation ferritic / martensitic steel (RAFM) as the substrate. The specific implementation steps are as follows:

[0084] (1) Surface treatment of the substrate. The substrate material was first polished on an automatic grinding machine using SiC sandpaper (400#, 600#, 800#, 1200#, 1800# in sequence) and diamond slurry, and then ultrasonically cleaned at room temperature. The cleaning process was carried out in the following order: the polished substrate was first placed in a 10wt% sodium hydroxide solution, then cleaned with ethanol and acetone, and finally soaked in deionized water for 20 minutes. The cleaned substrate was then dried in a drying oven.

[0085] (2) Preparation of precursor solution.

[0086] Preparation of chromium nitride precursor: Prepare analytical grade (AR) chromium chloride hexahydrate, urea, and anhydrous methanol. Weigh 1.3 g of chromium chloride hexahydrate and 1.8 g of urea and dissolve them in 10 ml of anhydrous methanol. Stir the solution at a constant temperature of 50 °C with a magnetic stirrer for 20 min until the solution completely turns into a dark green precursor.

[0087] Preparation of erbium oxide precursor: Prepare analytical grade (AR) erbium acetate tetrahydrate, n-butyl acetate, ethylene glycolamine, ethylene glycol monomethyl ether, ethyl acetate, turpentine oil, propionic acid, and rosin. Weigh 3g of erbium acetate tetrahydrate and dissolve it in a mixed solution of 25ml n-butyl acetate and 25ml ethylene glycol monomethyl ether to prepare the precursor solution. Place the solution in a magnetically stirred heating mantle and heat to 120℃ for 60min. After the solution boils, add 10ml ethyl acetate and 2ml diethanolamine as stabilizers, and stir until the solution becomes completely clear and transparent. Then add 2g rosin, 2ml propionic acid, and 5ml turpentine oil as film-forming promoters until the solution becomes a dark brown MOD erbium oxide precursor, which is then stored for later use.

[0088] (3) Precursor Coating. The chromium nitride precursor solution was coated using a dip-coating method. The substrate was first dip-coated at a speed of 1 mm / s. -1 Immerse the precursor at a rate of 1 mm / s until the matrix is ​​completely submerged. Hold for 5 minutes, then immerse at a rate of 1 mm / s. -1 The pulling speed is used to pull the substrate out of the precursor. During immersion and pulling, the substrate is kept perpendicular to the liquid surface to maintain liquid stability.

[0089] (4) Drying of the chromium nitride anti-corrosion and tritium-inhibiting coating. The RAFM steel substrate containing the precursor was dried in air at 60°C for 300 min, and organic matter was evaporated separately. The muffle furnace heating rate was 5°C·min. -1 .

[0090] (5) Sintering and forming of chromium nitride anti-corrosion and tritium-inhibiting coating. The dried substrate was calcined in an annealing furnace at 1000℃ for 6 hours under a nitrogen atmosphere. The nitrogen flow rate was precisely controlled to 300 sccm (300 mL·min under standard conditions) using a gas flow meter. -1 The heating and cooling rates are both 3℃·min. -1 .

[0091] (6) Preparation of composite coating. The erbium oxide precursor solution was coated using the dip-coating method. The sample was first dipped at a speed of 1 mm·s. -1 Immerse the sample in the precursor at a rate of 1 mm / s until the sample is completely submerged. Hold for 5 minutes, then immerse in the precursor at a rate of 1 mm / s. -1 The pulling speed is used to pull the substrate out of the precursor. During immersion and pulling, the substrate is kept perpendicular to the liquid surface to maintain liquid stability.

[0092] (7) Drying of the chromium nitride / erbium oxide composite ceramic anti-corrosion and tritium-inhibiting coating. Drying was performed in air at 120℃ and 470℃ for 15 min to evaporate low-melting-point and high-melting-point organic compounds, respectively. The muffle furnace heating rate was 5℃·min. -1 .

[0093] (8) Sintering and forming of chromium nitride / erbium oxide composite ceramic anti-corrosion and tritium-inhibiting coating. The dried coating sample was heated to 700℃ in an annealing furnace under air or argon atmosphere and sintered for 1 h to obtain the chromium nitride / erbium oxide composite ceramic anti-corrosion and tritium-inhibiting coating. The muffle furnace heating rate was 5℃·min. -1 .

[0094] Example 3

[0095] A method for preparing an AlN / Y2O3 corrosion-resistant and tritium-inhibiting coating, using low-activation ferritic / martensitic steel (RAFM) as the substrate, is described below:

[0096] (1) Surface treatment of the substrate. The substrate material was first polished on an automatic grinding machine using SiC sandpaper (400#, 600#, 800#, 1200#, 1800# in sequence) and diamond slurry, and then ultrasonically cleaned at room temperature. The cleaning process was carried out in the following order: the polished substrate was first placed in a 10% sodium hydroxide solution, then cleaned with ethanol and acetone, and finally soaked in deionized water for 20 minutes. The cleaned substrate was then dried in a drying oven.

[0097] (2) Preparation of precursor solution.

[0098] Preparation of aluminum nitride precursor: Prepare analytical grade (AR) aluminum chloride hexahydrate, urea, and anhydrous methanol. Weigh 1.2 g of aluminum chloride hexahydrate and 1.8 g of urea and dissolve them in 10 ml of anhydrous methanol. Stir the solution at a constant temperature of 50 °C with a magnetic stirrer for 20 min until the solution turns completely milky white, becoming the precursor.

[0099] Preparation of Yttrium Oxide (YO) Precursor Solution. Prepare analytical grade (AR) yttrium acetate, n-butyl acetate, ethylene glycolamine, ethylene glycol monomethyl ether, ethyl acetate, turpentine oil, propionic acid, and rosin. Weigh 3g of yttrium acetate and dissolve it in a 25ml mixture of n-butyl acetate and 25ml of ethylene glycol monomethyl ether to prepare the precursor solution. Place the solution in a magnetically stirred heating mantle and heat to 120℃ for 60min. After the solution boils, add 10ml of ethyl acetate and 2ml of diethanolamine as stabilizers, and stir until the solution becomes completely clear and transparent. Then add 2g of rosin, 2ml of propionic acid, and 5ml of turpentine oil as film-forming promoters until the solution becomes a yellow MOD precursor, which is then stored for later use.

[0100] (3) Precursor Coating. The aluminum nitride precursor solution is coated using a dip-coating method. The substrate is first dip-coated at a speed of 1 mm / s. -1 Immerse the precursor at a rate of 1 mm / s until the matrix is ​​completely submerged. Hold for 5 minutes, then immerse at a rate of 1 mm / s. -1 The pulling speed is used to pull the substrate out of the precursor. During immersion and pulling, the substrate is kept perpendicular to the liquid surface to maintain liquid stability.

[0101] (4) Drying of the aluminum nitride anti-corrosion and tritium-inhibiting coating. The RAFM steel substrate containing the precursor was dried in air at 60°C for 300 min, and organic matter was evaporated separately. The muffle furnace heating rate was 5°C·min. -1 .

[0102] (5) Sintering and forming of aluminum nitride anti-corrosion and tritium-inhibiting coating. The dried substrate was calcined in an annealing furnace at 1000℃ for 6 hours under a nitrogen atmosphere. The nitrogen flow rate was precisely controlled to be 300 sccm (300 mL·min under standard conditions) using a gas flow meter. -1 The heating and cooling rates are both 3℃·min. -1 .

[0103] (6) Preparation of composite coating. The yttrium oxide precursor solution was coated using a dip-coating method. The sample was first dipped at a speed of 1 mm / s... -1 Immerse the sample in the precursor at a rate of 1 mm / s until the sample is completely submerged. Hold for 5 minutes, then immerse in the precursor at a rate of 1 mm / s. -1 The pulling speed is used to pull the substrate out of the precursor. During immersion and pulling, the substrate is kept perpendicular to the liquid surface to maintain liquid stability.

[0104] (7) Drying of the aluminum nitride / yttrium oxide composite ceramic corrosion-resistant and tritium-inhibiting coating. Drying was performed in air at 120℃ and 470℃ for 15 min to evaporate low-melting-point and high-melting-point organic compounds, respectively. The muffle furnace heating rate was 5℃·min. -1 .

[0105] (8) Sintering and forming of aluminum nitride / yttrium oxide composite ceramic anti-corrosion and tritium-inhibiting coating. The dried sample was heated to 700℃ in an annealing furnace under air or argon atmosphere and sintered for 1 h to obtain the aluminum nitride / yttrium oxide composite ceramic anti-corrosion and tritium-inhibiting coating. The muffle furnace heating rate was 5℃·min. -1 .

[0106] Example 4

[0107] A method for preparing an AlN / Al2O3 corrosion-resistant and tritium-inhibiting coating, using low-activation ferritic / martensitic steel (RAFM) as the substrate, is described below:

[0108] (1) Surface treatment of the substrate. The substrate material was first polished on an automatic grinding machine using SiC sandpaper (400#, 600#, 800#, 1200#, 1800# in sequence) and diamond slurry, and then ultrasonically cleaned at room temperature. The cleaning process was carried out in the following order: the polished substrate was first placed in a 10% sodium hydroxide solution, then cleaned with ethanol and acetone, and finally soaked in deionized water for 20 minutes. The cleaned substrate was then dried in a drying oven.

[0109] (2) Preparation of precursor solution.

[0110] Preparation of aluminum nitride precursor: Prepare analytical grade (AR) aluminum chloride hexahydrate, urea, and anhydrous methanol. Weigh 1.2 g of aluminum chloride hexahydrate and 1.8 g of urea and dissolve them in 10 ml of anhydrous methanol. Stir the solution at a constant temperature of 50 °C with a magnetic stirrer for 20 min until the solution turns completely milky white, becoming the precursor.

[0111] Preparation of the alumina precursor solution. Prepare analytical grade (AR) aluminum acetate, n-butyl acetate, ethylene glycolamine, ethylene glycol monomethyl ether, ethyl acetate, turpentine oil, propionic acid, and rosin. Weigh 1 g of aluminum acetate and dissolve it in a 25 ml mixture of n-butyl acetate and 25 ml of ethylene glycol monomethyl ether to prepare the precursor solution. Place the solution in a magnetically stirred heating mantle and heat to 120 °C for 60 min. After the solution boils, add 10 ml of ethyl acetate and 2 ml of diethanolamine as stabilizers, and stir until the solution becomes completely clear and transparent. Then add 2 g of rosin, 2 ml of propionic acid, and 5 ml of turpentine oil as film-forming promoters until the solution becomes a light yellow MOD precursor, which is then stored for later use.

[0112] (3) Precursor Coating. The aluminum nitride precursor solution is coated using a dip-coating method. The substrate is first dip-coated at a speed of 1 mm / s. -1 Immerse the precursor at a rate of 1 mm / s until the matrix is ​​completely submerged. Hold for 5 minutes, then immerse at a rate of 1 mm / s. -1 The pulling speed is used to pull the substrate out of the precursor. During immersion and pulling, the substrate is kept perpendicular to the liquid surface to maintain liquid stability.

[0113] (4) Drying of the aluminum nitride anti-corrosion and tritium-inhibiting coating. The RAFM steel substrate containing the precursor was dried in air at 60°C for 300 min, and organic matter was evaporated separately. The muffle furnace heating rate was 5°C·min. -1 .

[0114] (5) Sintering and forming of aluminum nitride anti-corrosion and tritium-inhibiting coating. The dried substrate was calcined in an annealing furnace at 1000℃ for 6 hours under a nitrogen atmosphere. The nitrogen flow rate was precisely controlled to be 300 sccm (300 mL·min under standard conditions) using a gas flow meter. -1 The heating and cooling rates are both 3℃·min. -1 .

[0115] (6) Preparation of composite coating. The alumina precursor solution was coated using the dip-coating method. The sample was first dipped at a speed of 1 mm / s. -1 Immerse the sample in the precursor at a rate of 1 mm / s until the sample is completely submerged. Hold for 5 minutes, then immerse in the precursor at a rate of 1 mm / s. -1 The pulling speed is used to pull the substrate out of the precursor. During immersion and pulling, the substrate is kept perpendicular to the liquid surface to maintain liquid stability.

[0116] (7) Drying of the aluminum nitride / alumina composite ceramic anti-corrosion and tritium-inhibiting coating. Drying was performed in air at 120℃ and 470℃ for 15 min to evaporate low-melting-point and high-melting-point organic compounds, respectively. The muffle furnace heating rate was 5℃·min. -1 .

[0117] (8) Sintering and forming of aluminum nitride / alumina composite ceramic anti-corrosion and tritium-inhibiting coating. The dried sample was heated to 700℃ in an annealing furnace under air or argon atmosphere and sintered for 1 h to obtain the aluminum nitride / alumina composite ceramic anti-corrosion and tritium-inhibiting coating. The muffle furnace heating rate was 5℃·min. -1 .

[0118] The parts of this invention not described in detail are well-known to those skilled in the art. The embodiments described above are merely preferred embodiments of the invention, and do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Various modifications and improvements to the technical solutions of this invention made by those skilled in the art without departing from the spirit of the invention should fall within the protection scope defined by the claims of this invention.

Claims

1. A method for preparing a metal nitride MN / oxide M'2O3 composite ceramic corrosion-resistant and tritium-inhibiting coating, characterized in that, Includes the following steps: (1) Surface treatment of substrate The substrate was first ground and polished with SiC sandpaper and diamond slurry, and then ultrasonically cleaned at room temperature. The cleaning process was carried out in the following order: the polished substrate was first placed in sodium hydroxide solution, then cleaned with ethanol and acetone, and finally soaked in deionized water. The cleaned substrate was then dried in a drying oven. (2) Preparation of metal nitride MN and metal oxide M'2O3 precursor solutions Aluminum chloride hexahydrate or chromium chloride hexahydrate, along with urea, are dissolved in anhydrous methanol. The solution is heated and stirred to obtain a metal nitride MN precursor for coating; M = Al or Cr. Metal M' salts were dissolved in a mixed solution of n-butyl acetate and ethylene glycol monomethyl ether. The solution was heated and stirred, and then ethyl acetate, turpentine, and diethanolamine were added as stabilizers. Finally, rosin and propionic acid were added as film-forming promoters to prepare the metal oxide M'₂O₃ precursor for coating. M' = Al, Y, or Er; the molar ratio of aluminum chloride hexahydrate or chromium chloride hexahydrate to urea was 1:4 to 1:8; the propionic acid content was 1 to 10 wt%, the turpentine content was 10 to 20 wt%, the ethyl acetate content was 3 to 13 wt%, and the rosin content was 0.1 to 10 wt%; the volume fraction of diethanolamine was 4 to 10%, the volume fraction of n-butyl acetate was 40 to 60%, and the volume fraction of ethylene glycol monomethyl ether was 40 to 60%; the ratio of n-butyl acetate to ethylene glycol monomethyl ether in the mixed solution was 1:2 to 2:1; the M' content in the metal oxide M'₂O₃ precursor was 2 to 6 wt%. (3) Coating First, select the aforementioned metal nitride MN precursor solution and apply a coating film using the dip-coating method; (4) Drying of metal nitride MN ceramic anti-corrosion tritium barrier coating The coated substrate is first placed in an air atmosphere to keep it warm and dry the easily volatile solvents; (5) Sintering and forming of metal nitride MN ceramic anti-corrosion and tritium barrier coating The substrate after the coating is dried is heated to 800~1000 ℃ under a nitrogen atmosphere and sintered to obtain a metal nitride MN ceramic anti-corrosion and tritium barrier coating. (6) Preparation of composite coating The aforementioned metal oxide M'2O3 precursor solution was selected, and a composite coating was prepared on the previously coated sample using the dip-coating method. (7) Drying of metal nitride MN / oxide M'2O3 composite ceramic corrosion-resistant tritium-inhibiting coating After coating, the sample is first kept in an air atmosphere at 80~120℃ for 15~60 min to dry the volatile solvent, and then kept in an air atmosphere at 400~480℃ for 15~120 min to dry the non-volatile organic solvent. (8) Sintering and forming of metal nitride MN / oxide M'2O3 composite ceramic anti-corrosion and tritium barrier coating The dried coating sample was heated to 480~800 ℃ in air or argon atmosphere and sintered for 0.5~3h to obtain a metal nitride MN / oxide M'2O3 composite ceramic anti-corrosion and tritium barrier coating. In steps (4), (5), (7), and (8), the heating rate is 3~10℃·min. -1 .

2. The method according to claim 1, characterized in that: In step (1), the matrix material is selected from 316L stainless steel, low-activation ferritic / martensitic steel or high-Cr martensitic steel.

3. The method according to claim 1, characterized in that: In step (2), the metal M' salts used include one or more of M'Cl3·6H2O, (CH3COO)3M, and M'(NO3)3.

4. The method according to claim 1, characterized in that: In step (2), the solution is heated and stirred at a temperature of 60~80℃ for 10~20 min; or at a temperature of 100~120℃ for 60~120 min.

5. The method according to claim 1, characterized in that: The method further includes sample analysis of the M'2O3 precursor material obtained in step (2). The sample analysis should include grinding the sintered metal oxide M'2O3 ceramic and determining its crystal structure and elemental composition, and further determining the M' atomic content.

6. The method according to claim 3, characterized in that: The Er content measured in the precursor was 2-5 wt%.

7. The method according to claim 3, characterized in that: The mixed solution contains 1-10 wt% propionic acid, 10-20 wt% turpentine, 3-13 wt% ethyl acetate, and 0.1-10 wt% rosin; the volume fraction of diethanolamine is 4-10%, the volume fraction of n-butyl acetate is 40-60%, and the volume fraction of ethylene glycol monomethyl ether is 40-60%.

8. The method according to claim 1, characterized in that: In steps (3) and (6), the immersion and lifting speed is 1 mm × s. -1 The coating thickness is adjusted by repeatedly dipping and pulling, drying, and then dipping and pulling again.

Images