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CN-121852855-B - Multistage coating oxygen-mediated annealing preparation method based on RAFM steel/titanium nitride

CN121852855BCN 121852855 BCN121852855 BCN 121852855BCN-121852855-B

Abstract

The invention discloses a preparation method of a multistage coating oxygen-mediated annealing based on RAFM steel/titanium nitride, and belongs to the technical field of coating preparation. The method comprises the steps of adopting magnetron sputtering to deposit a TiN coating on the surface of a low-activation ferrite/martensite steel matrix, using a pure titanium target material, adopting a nitrogen-argon flow ratio of 1:13-1:18, carrying out background vacuum degree of 4-6 multiplied by 10 ‑5 Pa, carrying out deposition for 60-90min, applying no additional active heating to the matrix in the deposition process, placing a deposited coating sample in a quartz tube for encapsulation, providing trace oxygen atmosphere by virtue of air pressure in the tube, and then carrying out 800-1000 ℃ annealing treatment, and carrying out heat preservation for 90-120min. Through oxygen-mediated element diffusion and reaction, a multistage composite structure which sequentially comprises an inner oxidation layer, an Fe inner enrichment layer, a TiN layer, an Fe outer enrichment layer and an outer oxidation layer from the matrix to the outside is formed in situ in the TiN coating. The method disclosed by the invention is simple in process, no additional deposition of a transition layer is needed, the prepared multi-stage coating is well combined with a matrix interface, and the thermal shock resistance is excellent, so that the thermal shock resistance can bear more than 30 thermal shock cycles.

Inventors

  • ZHOU GANG
  • LUO YICHENG
  • LIU JIANRONG

Assignees

  • 中国科学院金属研究所

Dates

Publication Date
20260508
Application Date
20260318

Claims (10)

  1. 1. A multistage coating oxygen-mediated annealing preparation method based on RAFM steel/titanium nitride is characterized in that a physical vapor deposition technology is utilized to deposit a TiN coating on a low-activation ferrite/martensite steel substrate, an annealing treatment is carried out on a deposited sample, and a composite coating which sequentially comprises an inner oxide layer, an Fe inner enrichment layer, a TiN layer, an optional Fe outer enrichment layer and an outer oxide layer from the substrate to the outside is prepared in situ on the substrate, and the method comprises the following steps: Preparing a TiN coating on the surface of a low-activation ferrite/martensitic steel matrix by adopting a physical vapor deposition method of magnetron sputtering, wherein a pure titanium target is used, the introduced nitrogen-argon gas flow ratio is N 2 :Ar=1:10-1:20, the background vacuum degree is 4-8 multiplied by 10 -5 Pa, the nitrogen-argon gas flow partial pressure is 0.4-0.8Pa during deposition, the deposition time is 40-90min, no additional active heating is applied to the matrix during the deposition, and the temperature of the matrix is always kept in the room temperature range of 20-40 ℃; Placing the sample deposited with the TiN coating in a controllable trace oxygen atmosphere, wherein the controllable trace oxygen atmosphere is an argon-oxygen mixed atmosphere with the oxygen volume fraction of 0.1% -0.5%, and is provided by vacuum packaging treatment of a quartz tube, and the final total air pressure after vacuum packaging in the tube is set to be 4-8 multiplied by 10 -3 Pa; And (3) placing the material into a box furnace for annealing treatment, wherein the annealing temperature is 900-1000 ℃, the heat preservation time is 90-120min, the heating rate is 5-15 ℃ per min, cooling along with the furnace, and forming a multilayer alternating structure comprising at least one TiN layer, at least one oxide layer and at least one metal enrichment layer in situ in the TiN coating through oxygen-mediated element diffusion and reaction.
  2. 2. The preparation method of the multi-stage coating oxygen-mediated annealing based on RAFM steel/titanium nitride according to claim 1, wherein the low-activation ferrite/martensite steel is CLF-1 steel, and the chemical components of the steel comprise, by mass, 8.2-8.8% of Cr, 1.3-1.7% of W, 0.05-0.15% of Ta, 0.3-0.7% of Mn, 0.2-0.4% of V, 0.09-0.14% of C, 0.02-0.04% of N, and the balance of Fe.
  3. 3. The method for preparing the RAFM steel/titanium nitride based multistage coating oxygen mediated annealing according to claim 1, wherein the main component of the outer oxide layer and the inner oxide layer is CrTi 2 O 5 .
  4. 4. The preparation method of the multi-stage coating oxygen-mediated annealing based on RAFM steel/titanium nitride according to claim 1, wherein in the step (1), a titanium target with the purity of 99.99% is used, the introduced nitrogen-argon gas flow ratio is N 2 :Ar=1:13-1:16, the background vacuum degree is 4-6 multiplied by 10 -5 Pa, the partial pressure of nitrogen-argon gas flow is 0.3-0.6Pa during deposition, and the deposition time is 60-90min.
  5. 5. The method for preparing the multi-stage coating oxygen-mediated annealing based on RAFM steel/titanium nitride according to claim 1, wherein in the step (2), the controllable trace oxygen atmosphere is provided by setting the volume fraction of oxygen in a quartz tube to be 0.2% -0.4% and the total air pressure in the tube to be 6-8 x 10 -3 Pa.
  6. 6. The method for preparing the multi-stage coating oxygen-mediated annealing based on RAFM steel/titanium nitride according to claim 1, wherein in step (3), an inner oxide layer with the thickness of 0.2-0.3 μm is formed in situ between the TiN coating and the low-activation ferrite/martensite steel matrix through annealing treatment, the annealing temperature is 900-1000 ℃, the heat preservation time is 90-120min, the heating rate is 10-15 ℃ per min, and the steel is cooled along with a furnace.
  7. 7. The method for preparing the multi-stage coating oxygen-mediated annealing based on RAFM steel/titanium nitride according to claim 1, wherein in the step (3), an Fe inner enriched layer with the thickness of less than 0.2 μm is formed in situ between the TiN coating and the low-activation ferrite/martensite steel matrix through annealing treatment, the annealing temperature is 900-1000 ℃, the heat preservation time is 90-120min, the heating rate is 10-15 ℃ per min, and the alloy is cooled along with a furnace.
  8. 8. The preparation method of the multi-stage coating oxygen-mediated annealing based on RAFM steel/titanium nitride according to claim 1, wherein in the step (3), an Fe outer enrichment layer with the thickness of less than 0.3 μm is formed on one side close to the outer surface in the TiN coating in situ through annealing treatment, the annealing temperature is 1000 ℃, the heat preservation time is 90-120min, the heating rate is 10-15 ℃ per min, and the coating is cooled along with a furnace.
  9. 9. The preparation method of the multi-stage coating oxygen-mediated annealing based on RAFM steel/titanium nitride according to claim 1, wherein in the step (3), an outer oxide layer with the thickness smaller than 0.3 μm is formed on the outer surface of the TiN coating in situ through annealing treatment, the annealing temperature is 800-1000 ℃, the heat preservation time is 90-120min, the heating rate is 10-15 ℃ per min, and the coating is cooled along with a furnace.
  10. 10. The preparation method of the multi-stage coating oxygen-mediated annealing based on RAFM steel/titanium nitride according to claim 1, wherein the total thickness of the TiN coating deposited in the step (1) is 1.2-1.8 μm, the fluctuation of the overall thickness of the coating in the annealing process is not more than +/-10%, the thickness of the inner and outer oxide layers formed in situ in the annealing in the step (3) is 0.2-0.3 μm, the thickness of the Fe inner enrichment layer formed in situ in the annealing is less than 0.2 μm, and the thickness of the Fe outer enrichment layer formed in situ in the annealing is less than 0.3 μm.

Description

Multistage coating oxygen-mediated annealing preparation method based on RAFM steel/titanium nitride Technical Field The invention belongs to the technical field of coating preparation, and particularly relates to a preparation method of a multi-stage coating oxygen-mediated annealing based on RAFM steel/titanium nitride. Background Low-activation ferrite/martensite steel (RAFM steel) is used as an important material in the field of high-temperature structural materials because of its good low-activation characteristics, mechanical properties and irradiation resistance. In order to improve the service performance of the surface in a severe environment, a protective coating needs to be prepared on the surface of RAFM steel. The TiN ceramic coating is one of candidate materials because of its high hardness, high melting point, corrosion resistance and relatively close thermal expansion coefficient to RAFM steel. The difference of thermal expansion coefficients exists between the ceramic coating and the metal matrix, and the difference leads to the easy generation of interface stress of the coating in a high-temperature service environment, so that the peeling of the coating is initiated. The interfacial bonding means of the coating to the substrate include chemical bonding, physical adsorption and mechanical locking, wherein chemical bonding can provide higher interfacial bonding strength. Current common methods for improving the bond strength of ceramic coatings to substrates include high temperature diffusion treatments and the introduction of intermediate transition layers. High temperature diffusion processes form metallurgical bonds by promoting interdiffusion of elements between the coating and the substrate, but often require complex high temperature processing techniques. The introduction of the intermediate transition layer involves a multi-layer deposition process, which is relatively cumbersome in flow. The annealing treatment can promote the mutual diffusion of elements between the coating and the matrix, and form an interface region with gradually changed components. This method is used to optimize the interfacial bonding properties of the ceramic coating to the metal substrate. The diffusion behavior of Fe, cr and other elements in the matrix can be influenced by introducing trace oxygen in the annealing process, so that a multilayer structure is formed in the coating. Therefore, how to provide a relatively simple process, which can improve the interface bonding performance of the TiN coating and the RAFM steel substrate, is a key direction of those skilled in the art. Disclosure of Invention The invention aims to provide a novel multistage coating oxygen-mediated annealing in-situ preparation method based on RAFM steel/titanium nitride. In order to achieve the above object, the present invention provides the following technical solutions: A multistage coating in-situ preparation method based on RAFM steel/titanium nitride utilizes a physical vapor deposition technology to deposit a TiN coating on a low-activation ferrite/martensite steel matrix, carries out oxygen-mediated annealing treatment on a deposited sample, and prepares a composite coating which sequentially comprises an inner oxide layer, an Fe inner enrichment layer, a TiN layer, an optional Fe outer enrichment layer and an outer oxide layer from the matrix to the outside on the matrix in situ, wherein the method comprises the following steps: Preparing a TiN coating on the surface of a low-activation ferrite/martensitic steel matrix by adopting a physical vapor deposition method of magnetron sputtering, wherein a pure titanium target is used, the introduced nitrogen-argon gas flow ratio is N 2:Ar=1:10-1:20, the background vacuum degree is 4-8 multiplied by 10 -5 Pa, the nitrogen-argon gas flow partial pressure is 0.4-0.8Pa during deposition, the deposition time is 40-90min, no additional active heating is applied to the matrix during the deposition, and the temperature of the matrix is always kept in the room temperature range of 20-40 ℃; Placing the sample deposited with the TiN coating in a controllable trace oxygen atmosphere, wherein the controllable trace oxygen atmosphere is an argon-oxygen mixed atmosphere with the oxygen volume fraction of 0.1% -0.5%, and is provided by vacuum packaging treatment of a quartz tube, and the final total air pressure after vacuum packaging in the tube is set to be 4-8 multiplied by 10 -3 Pa; And (3) placing the material into a box furnace for annealing treatment, wherein the annealing temperature is 900-1000 ℃, the heat preservation time is 90-120min, the heating rate is 5-15 ℃ per min, cooling along with the furnace, and forming a multilayer alternating structure comprising at least one TiN layer, at least one oxide layer and at least one metal enrichment layer in situ in the TiN coating through oxygen-mediated element diffusion and reaction. Further, the low-activation ferrite/martensite steel