Low-activation ferrite martensitic steel self-oxidation film, preparation method and application

Abstract

The invention discloses a low-activation ferrite martensitic steel self-oxidation film, a preparation method and application, and relates to the technical field of fusion reactor cladding structure materials. Comprising the following steps that a low-activation ferrite martensitic steel substrate is ground, polished and cleaned; vacuumizing the vacuum heating system and carrying out empty burning; after the empty burning is finished and the vacuum heating system is cooled to room temperature, putting the substrate into a sample chamber of the vacuum heating system and sealing; the sample chamber is vacuumized to enable the vacuum degree to reach 1.0 * 10 <-7 >-1.0 * 10 <-3 > Pa, the heating temperature is 500-700 DEG C, heat treatment is conducted for 1-15 days under the condition, and the self-oxidation film is prepared on the surface of the low-activation ferrite martensitic steel; the prepared self-oxidation film has good tritium permeation resistance, the preparation method of the self-oxidation film is simple, and compared with a tritium permeation resistance coating preparation method in the prior art, the cost is lower.

Description

Technical Field

[0001] The invention relates to the technical field of fusion reactor cladding structural materials, and in particular to a low-activated ferrite martensitic steel self-oxidation film, a preparation method and application thereof. Background Art

[0002] The tritium breeder blanket is one of the core components of the fusion reactor, which is responsible for obtaining energy and maintaining the self-sustaining function of tritium fuel. The working environment of the blanket is harsh, and it needs to work under strong neutron irradiation, electromagnetic radiation, high heat load, complex mechanical load and physical and chemical shock. The penetration and retention of tritium in the blanket structure material will damage the performance of the material, accelerate the failure process, and cause the leakage of radioactive tritium. Therefore, reducing the penetration of tritium through the blanket structure material and improving the tritium barrier of the blanket material are one of the important factors that need to be considered in the design of the blanket structure material.

[0003] Low-activated ferritic martensitic steel (RAFM steel) is the best candidate structural material for the fusion demonstration reactor (DEMO) and ITER tritium breeder experimental blanket module. It exhibits good structural stability, thermal expansion coefficient, radiation resistance, mechanical properties and high thermal conductivity, and has low manufacturing cost and mature industrial base.

[0004] In order to improve the tritium barrier performance of cladding structural materials, surface engineering has attracted much attention as a performance improvement method that is both economical and practical. Among them, there are many studies on Al2O3 tritium barrier coatings, but there are no reports on using the substrate to self-oxidize to improve the tritium barrier ability and modify the tritium barrier performance of structural materials. In addition, the oxide film obtained under conventional heat treatment conditions does not have good tritium penetration resistance. Summary of the invention

[0005] The present invention aims to solve the technical problem that the prior art lacks the application of low-activated ferrite martensitic steel self-oxidation film in blocking tritium and inhibiting tritium penetration, and aims to provide a low-activated ferrite martensitic steel self-oxidation film, a preparation method and an application. The self-oxidation film prepared by the present invention has good tritium penetration resistance, and the preparation method of the self-oxidation film is simple. Compared with the prior art method for preparing tritium barrier coatings, the present invention has lower cost.

[0006] The present invention is achieved through the following technical solutions:

[0007] The first object of the present invention is to provide a method for preparing a low-activated ferrite martensitic steel self-oxidation film, comprising the following steps:

[0008] The low-activated ferrite martensitic steel substrate is ground, polished and cleaned;

[0009] Evacuate the vacuum heating system and perform empty firing;

[0010] After the vacuum heating system is cooled to room temperature, the substrate is placed in the sample chamber of the vacuum heating system and sealed;

[0011] The sample chamber was evacuated to a vacuum degree of 1.0×10 -7 ~1.0×10 -3 Pa, the heating temperature is 500-700°C, and the heat treatment is performed for 1-15 days under this condition to prepare a self-oxidation film on the surface of low-activated ferrite martensitic steel.

[0012] Furthermore, the low-activation ferrite martensitic steel is CLF-1 steel, and the mass fractions of the components of the CLF-1 steel are: 8.0% Cr, 1.5% W, 0.5% Mn, 0.3% V, 0.1% Ta, 0.11% C, ≤0.0015% O, ≤0.0048% N, and the rest is Fe.

[0013] Furthermore, it is characterized in that the grinding and polishing comprises:

[0014] Use 800#, 1000#, 2000#, 3000# metallographic polishing sandpaper to perform preliminary polishing on the surface of the substrate;

[0015] Finely polish the substrate surface using a polishing cloth and polishing compound.

[0016] Furthermore, the step of evacuating the vacuum heating system and performing empty burning comprises:

[0017] The vacuum heating system was evacuated to a vacuum better than 1×10 -6 Pa, the heating temperature is 500-800°C, and the processing time is 1-2h.

[0018] Furthermore, the empty burning operation is repeated 2 times or more.

[0019] Furthermore, the vacuum heating system comprises a sample chamber, a heating system and a vacuum pipeline, wherein the sample chamber is arranged in the heating system, the sample chamber has an openable and sealable sample inlet chamber, and the sample chamber is connected to the vacuum pipeline.

[0020] Furthermore, the vacuum pumping pipeline has two branch pipelines, one branch pipeline is provided with a pre-evacuation valve and connected to a mechanical pump, and the other branch pipeline is provided with a molecular pump valve and connected to a molecular pump.

[0021] The second object of the present invention is to provide a self-oxidation film prepared by the above method.

[0022] The third object of the present invention is to provide the use of the self-oxidized film prepared by the above method in tritium breeding blanket materials.

[0023] Furthermore, the tritium breeder blanket material includes CLF-1 steel and a self-oxidation film arranged on the surface thereof.

[0024] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0025] The present invention prepares a self-oxidation film on the surface of CLF-1 low-activated steel. The surface is uniform and dense, has a high surface flatness, and is free of defects such as cracks and holes. The self-oxidation film is subjected to a hydrogen isotope gas driven permeation test. The permeation signal is 10 -10 The signal of deuterium penetration is 2 orders of magnitude lower than that of substrate deuterium penetration, which proves that the self-oxidation film prepared on the surface of CLF-1 low-activated steel by this method has good tritium penetration resistance. The preparation method of the self-oxidation film is simple, and compared with the prior art method for preparing tritium barrier coating, the cost of the present invention is lower. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without creative work. In the drawings:

[0027] Figure 1 The XRD spectrum of the CLF-1 low-activated steel self-oxidation film prepared in Example 2 of the present invention;

[0028] Figure 2 The SEM cross-sectional image (100 μm) and oxygen content distribution of the CLF-1 low-activated steel self-oxidation film prepared in Example 2 of the present invention;

[0029] Figure 3 This is a SEM cross-sectional image (20 μm) of the CLF-1 low-activated steel self-oxidation film prepared in Example 2 of the present invention;

[0030] Figure 4 This is a hydrogen isotope (D2) gas phase permeation test curve of the CLF-1 low-activated steel self-oxidation film prepared in Example 2 of the present invention;

[0031] Figure 5 It is a structural schematic diagram of the vacuum heating system of the present invention.

[0032] Marks and corresponding parts names in the attached drawings:

[0033] 1-sample chamber, 2-sample injection chamber, 3-heating system, 4-vacuum pipeline, 5-main valve, 6-pre-evacuation valve, 7-mechanical pump, 8-molecular pump valve, 9-molecular pump. DETAILED DESCRIPTION

[0034] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the technical solutions in the embodiments of the present invention are clearly and completely described below in combination with the embodiments and drawings. Obviously, the schematic implementation modes of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0035] The following is a detailed description of the embodiments of the low-activated ferrite martensitic steel self-oxidation film, preparation method and application of the present invention with appropriate reference to the accompanying drawings. However, there may be cases where unnecessary detailed descriptions are omitted. For example, there are cases where detailed descriptions and repeated descriptions of well-known matters are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art.

[0036] The "range" disclosed in this application is defined in the form of a lower limit and an upper limit, and a given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of the particular range. The range defined in this way can be inclusive or exclusive of the end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a range.

[0037] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0038] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0039] Unless otherwise specified, the terms "include" and "comprising" mentioned in this application may be open-ended or closed-ended. For example, the terms "include" and "comprising" may mean that other substances not listed may also be included or only the listed substances may be included.

[0040] If there is no special explanation, all steps of the present application can be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), which means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0041] The technical solution of the present invention is to provide a method for preparing a low-activated ferrite martensitic steel self-oxidation film, comprising the following steps:

[0042] The low-activated ferrite martensitic steel substrate is ground, polished and cleaned;

[0043] Evacuate the vacuum heating system and perform empty firing;

[0044] After the vacuum heating system is cooled to room temperature, the substrate is placed in the sample chamber of the vacuum heating system and sealed;

[0045] The sample chamber was evacuated to a vacuum degree of 1.0×10 -7 ~1.0×10 -3 Pa, the heating temperature is 500-700°C, and the heat treatment is performed for 1-15 days under this condition to prepare a self-oxidation film on the surface of low-activated ferrite martensitic steel.

[0046] By the preparation method of the present invention, a self-oxidation film is prepared on the surface of low-activated ferrite martensitic steel. The film surface is uniform and flat, with high density. It has good tritium penetration resistance as verified by experiments, and shows good engineering application prospects.

[0047] Preferably, the low-activated ferrite martensitic steel is CLF-1 steel, and the mass fractions of the components of the CLF-1 steel are: 8.0% Cr, 1.5% W, 0.5% Mn, 0.3% V, 0.1% Ta, 0.11% C, ≤0.0015% O, ≤0.0048% N, and the rest is Fe. CLF-1 steel is a RAFM steel independently developed by my country, with low cost, and has been widely used in tritium breeding blanket materials.

[0048] Preferably, the grinding and polishing comprises:

[0049] Use 800#, 1000#, 2000#, 3000# metallographic polishing sandpaper to perform preliminary polishing on the surface of the substrate;

[0050] The substrate surface is finely polished using a polishing cloth and a polishing agent, wherein the polishing agent is preferably a metallographic polishing agent, and the particle size of the metallographic polishing agent is preferably 0.5 μm.

[0051] Preferably, the step of evacuating the vacuum heating system and performing empty burning comprises:

[0052] The vacuum heating system was evacuated to a vacuum better than 1×10 -6 Pa, the heating temperature is 500-800°C, and the processing time is 1-2h.

[0053] Preferably, the empty burning operation is repeated 2 times or more. Repeating the empty burning operation multiple times can ensure that the system is in a clean state.

[0054] The vacuum heating system 3 used in the preparation process of the present invention includes a sample chamber 1, a heating system 3 and a vacuum pipeline 4. The sample chamber 1 is arranged in the heating system 3, and a heat source is provided for the sample through the heating system 3. The sample chamber 1 has an openable and sealable sample injection chamber 2 for easy injection and sampling. The sample chamber 1 is connected to the vacuum pipeline 4 for easy vacuuming of the system. The vacuum pipeline 4 is provided with a main valve 5 and has two branch pipelines, one of which is provided with a pre-pumping valve 6 and connected to a mechanical pump 7, and the other branch pipeline is provided with a molecular pump valve 8 and connected to a molecular pump 9.

[0055] The self-oxidation film prepared by the invention is used in a tritium breeding blanket material. The tritium breeding blanket material comprises CLF-1 steel and a self-oxidation film arranged on the surface of the steel.

[0056] The technical solution of the present invention is further described in detail below in conjunction with embodiments.

[0057] It should be noted that the experimental methods used in the examples are conventional methods unless otherwise specified. The materials, reagents, methods and instruments used are conventional materials, reagents, methods and instruments in the art unless otherwise specified, and can be obtained by those skilled in the art through commercial channels.

[0058] Example 1

[0059] A method for preparing a low-activated ferrite martensitic steel self-oxidation film, the specific steps of which are as follows:

[0060] (1) The CLF-1 low-activated ferrite-martensitic steel matrix was processed into a disc with a diameter of 12 mm.

[0061] (2) Grinding and polishing the substrate, the specific operations are as follows:

[0062] Use 800# metallographic polishing sandpaper to polish the processed samples, remove the burrs and scratches generated during the processing, and obtain a smooth surface.

[0063] Use 1000#, 2000#, and 3000# metallographic polishing sandpaper successively to perform preliminary polishing on the polished surface, gradually polishing the scratches in the polishing process to obtain a smooth surface.

[0064] The substrate surface was finely polished using a polishing cloth and a 0.5 μm metallographic polishing agent to obtain a smooth mirror surface.

[0065] (3) Cleaning the substrate, the specific operation is as follows:

[0066] Place the polished substrate in a 50 mL beaker, add 20 mL of anhydrous ethanol, place the beaker in an ultrasonic cleaning machine, and perform ultrasonic cleaning at room temperature for 10 minutes. After the cleaning is completed, take it out and blow dry it with a hair dryer for later use.

[0067] (4) Pre-treat the pipelines of the heat treatment system equipment. The specific operations are as follows:

[0068] The sealed system is evacuated to a high vacuum, and the predetermined pressure is 8.0×10 -7 Pa, turn on the heating system and set the system temperature to 800℃ for 2h.

[0069] (5) After the empty burning is completed, wait for the system temperature to cool to room temperature before placing the substrate. The specific operation is as follows:

[0070] Close the molecular pump valve, close the molecular pump, close the main valve, close the mechanical pump, open the injection chamber, place the sample on the sample table in the sample chamber, close the injection chamber, seal the pipeline, and note that the copper gasket needs to be replaced when sealing.

[0071] (6) Perform an airtightness check on the sealed system. The specific operations are as follows:

[0072] Open the main valve, open the pre-pumping valve, use a mechanical pump to pre-pump, and wait until the pressure drops to 1Pa, which proves that the air tightness is good.

[0073] (7) The system that has passed the airtightness inspection is subjected to ultra-high vacuum pumping and oxide film preparation. The specific operations are as follows:

[0074] Close the pre-evacuation valve, open the molecular pump valve, and after the air pressure stabilizes, turn on the molecular pump to pump ultra-high vacuum into the system and adjust the vacuum degree to 1.0×10 -4 Pa, the heat treatment temperature is 700℃, and the heat treatment time is 6 days.

[0075] (8) After the substrate is heated, take out the sample. The specific operation is as follows:

[0076] After the system cools down to room temperature, close the molecular pump valve, turn off the molecular pump, close the main valve, turn off the mechanical pump, open the sample chamber, take out the sample, close the sample chamber, seal the pipeline, turn on the mechanical pump to pre-vacuum the system, keep the system clean, and prevent atmospheric contamination of the pipeline.

[0077] The self-oxidation film of CLF-1 low-activation steel prepared in this example has a uniform and dense surface, high surface flatness, no defects such as cracks and holes, a thickness of about 5 μm, and a phase mainly composed of iron-chromium oxides. This shows that this method can prepare a uniform self-oxidation film on the surface of CLF-1 low-activation steel.

[0078] Example 2

[0079] A method for preparing a low-activated ferrite martensitic steel self-oxidation film, the specific steps of which are as follows:

[0080] (1) Process the CLF-1 low-activated ferrite martensitic steel matrix into a 20 mm diameter disc

[0081] (2) Grinding and polishing the substrate, the specific operation is as follows:

[0082] Use 800# metallographic polishing sandpaper to polish the processed samples, remove the burrs and scratches generated during the processing, and obtain a smooth surface.

[0083] Use 1000#, 2000#, and 3000# metallographic polishing sandpaper successively to perform preliminary polishing on the polished surface, gradually polishing the scratches in the polishing process to obtain a smooth surface.

[0084] The substrate surface was finely polished using a polishing cloth and a 0.5 μm metallographic polishing agent to obtain a smooth mirror surface.

[0085] (3) Cleaning the substrate, the specific operation is as follows:

[0086] Place the polished substrate in a 50 mL beaker, add 20 mL of anhydrous ethanol, place the beaker in an ultrasonic cleaning machine, and perform ultrasonic cleaning at room temperature for 10 minutes. After the cleaning is completed, take it out and blow dry it with a hair dryer for later use.

[0087] (4) Pre-treat the pipelines of the heat treatment system equipment. The specific operations are as follows:

[0088] The sealed system is evacuated to a high vacuum, and the predetermined pressure is 1.0×10 -6 Pa, turn on the heating system and set the system temperature to 800℃ for 2h.

[0089] (5) After the empty burning is completed, wait for the system temperature to cool to room temperature before placing the substrate. The specific operation is as follows:

[0090] Close the molecular pump valve, close the molecular pump, close the main valve, close the mechanical pump, open the injection chamber, place the sample on the sample table in the sample chamber, close the injection chamber, seal the pipeline, and note that the copper gasket needs to be replaced when sealing.

[0091] (6) Perform an airtightness check on the sealed system. The specific operations are as follows:

[0092] Open the main valve, open the pre-pumping valve, use a mechanical pump to pre-pump, and wait until the pressure drops to about 0.8Pa, which proves that the air tightness is good.

[0093] (7) The system that has passed the airtightness inspection is subjected to ultra-high vacuum pumping and oxide film preparation. The specific operations are as follows:

[0094] Close the pre-evacuation valve, open the molecular pump valve, and after the air pressure stabilizes, turn on the molecular pump to pump ultra-high vacuum into the system and adjust the vacuum degree to 1.0×10 -5Pa, the heat treatment temperature is 500℃, and the heat treatment time is 15 days.

[0095] (8) After the substrate is heated, take out the sample. The specific operation is as follows:

[0096] After the system cools down to room temperature, close the molecular pump valve, turn off the molecular pump, close the main valve, turn off the mechanical pump, open the sample chamber, take out the sample, close the sample chamber, seal the pipeline, turn on the mechanical pump to pre-vacuum the system, keep the system clean, and prevent atmospheric contamination of the pipeline.

[0097] The surface of the CLF-1 low-activated steel self-oxidation film prepared in this example is uniform and dense, has a high surface flatness, and has no defects such as cracks and holes. The self-oxidation film is subjected to a hydrogen isotope gas driven permeation test, and the permeation signal is 10 -10 The deuterium permeation signal of the substrate is 2 orders of magnitude lower than that of the substrate, indicating that the self-oxidized film prepared on the surface of CLF-1 low-activated steel by this method has good tritium permeation resistance.

[0098] Finally, it should be noted that the above specific embodiments are only used to explain in detail the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above description is only a specific implementation method of the present invention and is not used to limit the protection scope of the present invention. Although the present invention is described in detail with reference to the above specific embodiments, ordinary technicians in this field should understand that it is still possible to modify the technical solutions recorded in the above embodiments, or to replace or improve some or all of the technical features therein. These modifications, equivalent replacements and improvements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and description of the present invention.

Claims

1. A method for preparing a low-activated ferrite martensitic steel self-oxidation film, characterized in that: The following steps are involved: The low-activated ferrite martensitic steel substrate is ground, polished and cleaned; Evacuate the vacuum heating system and perform empty firing; After the vacuum heating system is cooled to room temperature, the substrate is placed in the sample chamber of the vacuum heating system and sealed; The sample chamber was evacuated to a vacuum degree of 1.0×10 -7 ~1.0×10 -3 Pa, the heating temperature is 500-700°C, and the heat treatment is performed for 1-15 days under this condition to prepare a self-oxidation film on the surface of low-activated ferrite martensitic steel.

2. The method for preparing a low-activated ferrite martensitic steel self-oxidation film according to claim 1, characterized in that: The low-activation ferrite martensitic steel is CLF-1 steel, and the mass fractions of the components of the CLF-1 steel are: 8.0% Cr, 1.5% W, 0.5% Mn, 0.3% V, 0.1% Ta, 0.11% C, ≤0.0015% O, ≤0.0048% N, and the rest is Fe.

3. The method for preparing a low-activated ferrite martensitic steel self-oxidation film according to claim 1, characterized in that: The grinding and polishing comprises: Use 800#, 1000#, 2000#, 3000# metallographic polishing sandpaper to perform preliminary polishing on the surface of the substrate; Finely polish the substrate surface using a polishing cloth and polishing compound.

4. The method for preparing a low-activated ferrite martensitic steel self-oxidation film according to claim 1, characterized in that: The vacuum heating system is evacuated and then subjected to empty burning, which comprises: The vacuum heating system was evacuated to a vacuum better than 1×10 -6 Pa, the heating temperature is 500-800°C, and the processing time is 1-2h.

5. The method for preparing a low-activated ferrite martensitic steel self-oxidation film according to claim 1, characterized in that: The empty burning operation is repeated 2 times or more.

6. The method for preparing a low-activated ferrite martensitic steel self-oxidation film according to claim 1, characterized in that: The vacuum heating system (3) comprises a sample chamber (1), a heating system (3) and a vacuum pipeline (4); the sample chamber (1) is arranged in the heating system (3); the sample chamber (1) has an openable and sealable sample inlet chamber (2); and the sample chamber (1) is connected to the vacuum pipeline (4).

7. The method for preparing a low-activated ferrite martensitic steel self-oxidation film according to claim 6, characterized in that: The vacuum pumping pipeline (4) has two branch pipelines, one branch pipeline is provided with a pre-evacuation valve (6) and is connected to a mechanical pump (7), and the other branch pipeline is provided with a molecular pump valve (8) and is connected to a molecular pump (9).

8. A low-activated ferrite martensitic steel self-oxidation film, characterized in that: Prepared by the method according to any one of claims 1 to 7.

9. Use of the self-oxidized film as claimed in claim 8 in tritium breeding blanket materials.

10. The use according to claim 9, characterized in that: The tritium breeder blanket material comprises CLF-1 steel and a self-oxidation film arranged on the surface of the steel.

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