Controllable oxidation high performance nanometal multilayer film and manufacturing method thereof

Abstract

This invention provides a method for preparing a controllable oxidation high-performance nano-metal multilayer film. Using stainless steel as a substrate and a yttrium target as an arc source, yttrium deposition is performed on the substrate using a yttrium arc to obtain a transition layer containing yttrium oxide and yttrium. The thickness of the transition layer is 100-200 nm, and the yttrium oxide content in the transition layer ranges from 7% to 12%. Yttrium deposition is then performed on the transition layer using a yttrium arc to obtain a yttrium layer. Using a niobium target as an arc source, niobium deposition is performed on the yttrium layer using a niobium arc to obtain a niobium layer. One cycle of the yttrium layer and niobium layer is used as a loop layer, and this process is repeated N times to obtain a controllable oxidation high-performance nano-metal multilayer film containing the transition layer and N loop layers, where 10 ≤ N ≤ 50. This method yields a nano-metal multilayer film with good adhesion to the substrate, uniform grain size, and a large number of columnar crystals that enhance system stability. The film also exhibits controllable oxidation at high temperatures to enhance thermodynamic stability and mechanical properties.

Description

Technical Field

[0001] This invention relates to the field of coating technology, and in particular to a controllable oxidation high-performance nano-metal multilayer film and its fabrication method. Background Technology

[0002] Nuclear energy, along with hydropower and wind power, stands as one of the world's three major energy pillars. In fact, nuclear energy is far more stable than the latter two. However, with the continuous development of nuclear energy technology and the alternation of old and new reactor types, higher demands are placed on the materials used in nuclear reactors. The materials used in the loop piping of a nuclear power plant are a crucial part of the entire nuclear reactor, especially the critical piping in the primary and secondary loops. During operation, these piping systems face high radiation flux and high-temperature, high-pressure environments, which places even greater demands on their performance in complex environments.

[0003] Currently, the main material of these pipes is mostly austenitic stainless steel, but its performance is gradually becoming unsatisfactory with technological advancements. Nanoscale metal multilayer films can be fabricated on austenitic stainless steel pipes. The high-density interfaces of these nanoscale multilayer films can annihilate radiation-induced defects, greatly enhancing the pipe's radiation resistance to prevent failure. However, the thermal stability and mechanical properties require consideration of the metal composition. Summary of the Invention

[0004] In view of this, the present invention provides a controllable oxidation high-performance nano-metal multilayer film with excellent radiation resistance, thermal stability and mechanical properties, and a method for fabricating the same, which can maintain the integrity of the structure and excellent mechanical properties at 800℃.

[0005] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0006] In a first aspect, embodiments of the present invention provide a method for preparing a controllable oxidation high-performance nano-metal multilayer film, the preparation method comprising:

[0007] Using stainless steel as a substrate and yttrium target as an arc source, yttrium deposition is performed on the substrate based on the yttrium arc to obtain a transition layer containing yttrium oxide and yttrium. The thickness of the transition layer is 100-200 nm, and the yttrium oxide content in the transition layer is in the range of 7%-12%.

[0008] Yttrium deposition is performed on the transition layer using a yttrium arc to obtain a yttrium layer;

[0009] Using a niobium target as an electric arc source, niobium is deposited on the yttrium layer based on the niobium arc to obtain a niobium layer;

[0010] Using one yttrium layer and one niobium layer as a cycle layer, N cycles are repeated to obtain a controllable oxidation high-performance nano-metal multilayer film containing a transition layer and N cycle layers, wherein 10 ≤ N ≤ 50.

[0011] Preferably, before the step of using stainless steel as a substrate, a yttrium target as an arc source, and performing yttrium deposition on the substrate based on a yttrium arc to obtain a transition layer containing yttrium oxide and yttrium, the method includes:

[0012] The vacuum level in the deposition chamber was evacuated to 4 × 10⁻⁴ using both mechanical and molecular pumps. -2 Pa-4×10 -3 Pa, the bending magnetic field is 2.0A, the deposition temperature is 25℃, and when the FCVA equipment starts the arc, the Y arc starting current is first controlled to be 90-120A, the duty cycle is 90%, and the bias voltage is -800V, -600V, -400V, -200V decreasing sequentially every 40s.

[0013] Preferably, the process of using stainless steel as a substrate, a yttrium target as an arc source, and depositing yttrium on the substrate based on a yttrium arc to obtain a transition layer comprising yttrium oxide and yttrium includes:

[0014] Using stainless steel as a substrate, a yttrium target is used as an arc source with a bias voltage of -100V and a duty cycle of 30% for yttrium deposition. Yttrium reacts with residual oxygen on the substrate surface to generate a yttrium oxide thin layer. The yttrium oxide thin layer forms chemical bonds with the substrate to obtain a transition layer containing yttrium oxide and yttrium.

[0015] Preferably, the step of using a niobium target as an arc source to deposit niobium on the yttrium layer to obtain a niobium layer includes:

[0016] On the yttrium layer, a niobium target is used as an arc source, the niobium arc ignition current is set to 130A, the bias voltage is kept at -100V, and the duty cycle is kept at 30% to deposit the niobium layer.

[0017] Preferably, after repeating the process of using one yttrium layer and one niobium layer as a cycle as a loop layer, and repeating N cycles to obtain a controllable oxidation high-performance nano-metal multilayer film containing a transition layer and N loop layers, the process further includes:

[0018] The controllable oxidation high-performance nano-metal multilayer film was placed in a tube furnace and annealed at 800°C for one hour under a vacuum of 3×10-3 Pa, followed by furnace cooling.

[0019] Secondly, the controllable oxidation high-performance nano-metal multilayer film prepared by the controllable oxidation high-performance nano-metal multilayer film preparation method described above, according to the embodiments of the present invention, includes:

[0020] A transition layer, a yttrium layer, and a niobium layer are sequentially grown on a stainless steel substrate; the transition layer comprises yttrium oxide and yttrium, wherein the thickness of the transition layer is 100-200 nm, and the yttrium oxide content in the transition layer ranges from 7% to 12%;

[0021] Using one yttrium layer and one niobium layer as a cycle layer, N cycles are repeated to obtain a controllable oxidation high-performance nano-metal multilayer film containing a transition layer and N cycle layers, wherein 10 ≤ N ≤ 50.

[0022] This invention provides a method for preparing a controllable oxidation high-performance nano-metal multilayer film. Using stainless steel as a substrate and a yttrium target as an arc source, yttrium deposition is performed on the substrate based on a yttrium arc to obtain a transition layer containing yttrium oxide and yttrium. The thickness of the transition layer is 100-200 nm, and the yttrium oxide content in the transition layer ranges from 7% to 12%. Yttrium deposition is then performed on the transition layer based on a yttrium arc to obtain a yttrium layer. Using a niobium target as an arc source, niobium deposition is then performed on the yttrium layer based on a niobium arc to obtain a niobium layer. One cycle of the yttrium layer and niobium layer is used as a loop layer, and this process is repeated N times to obtain a controllable oxidation high-performance nano-metal multilayer film containing a transition layer and N loop layers, wherein 10 ≤ N ≤ 50. Compared with the prior art, the method for preparing a controllable oxidation high-performance nano-metal multilayer film provided by this invention has the following beneficial effects:

[0023] Y reacts with the small amount of residual oxygen on the substrate surface to form a Y₂O₃ thin layer. This thin layer forms chemical bonds with the substrate, greatly improving the adhesion of the coating. The selected Nb / Y system has a high positive enthalpy of mixing (+30 KJ / mol), meaning that this system is immiscible at high temperatures, which is crucial for ensuring its structural stability. At high temperatures, the Y layer undergoes controlled oxidation to produce yttrium oxide, enhancing the overall structure, thermal stability, and mechanical properties. This invention prepares a Nb / Y nanoscale metal multilayer film with good adhesion to the substrate, uniform grain size, and a large number of columnar crystals that enhance the system's stability. Furthermore, it exhibits controllable oxidation at high temperatures to enhance thermodynamic stability and mechanical properties. Attached Figure Description

[0024] Figure 1 This is a SEM cross-sectional image of the Nb / Y nano-metal multilayer film in Example 1 of the present invention.

[0025] Figure 2 This is a SEM cross-sectional image of the Nb / Y nano-metal multilayer film in the annealed state at 700℃ in Example 1 of the present invention;

[0026] Figure 3 for Figure 2 High-resolution transmission electron microscopy (TEM) diagram of the interface structure of a medium-Nb / Y nano-metal multilayer film in annealed state at 700℃.

[0027] Figure 4 for Figure 1 Element content diagram of the transition layer (red box) in the middle and lower layers;

[0028] Figure 5 This is a diagram showing the elemental composition in Example 2 of the present invention;

[0029] Figure 6 This is a diagram showing the elemental composition in Example 3 of the present invention;

[0030] Figure 7 This is a SEM cross-sectional view of the annealed temperature of 800℃ in Example 4 of the present invention;

[0031] Figure 8 This is a SEM cross-sectional view of the annealed temperature of 800℃ in Example 5 of the present invention;

[0032] Figure 9 This is a SEM cross-sectional view of the annealed temperature of 800℃ in Example 6 of the present invention;

[0033] Figure 10 This is a SEM cross-sectional view of the annealed material at 800℃ in Comparative Example 1 of this invention;

[0034] Figure 11 This is a SEM cross-sectional view of the annealed material at 800℃ in Comparative Example 2 of this invention;

[0035] Figure 12 This is a SEM cross-sectional view of the annealed material at 800℃ in Comparative Example 3 of this invention. Detailed Implementation

[0036] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0038] Before providing a further detailed description of the present invention, the nouns and terms used in the embodiments of the present invention will be explained, and the nouns and terms used in the embodiments of the present invention shall be interpreted as follows.

[0039] The technical solution of this invention mainly includes two steps: pretreatment and preparation process. While the preparation processes differ, the sample pretreatment is completely identical. The pretreatment mainly includes:

[0040] (1) Magnetic filtration ion plating vacuum system treatment: Before placing the sample, use a vacuum cleaner to clean the deposition chamber to remove dust and adhering substances. Use anhydrous ethanol and gauze to wipe the target and sample stage.

[0041] (2) SUS304 substrate treatment: The substrate was polished with sandpaper of different grits to remove surface oxides and scratches. After polishing, it was ultrasonically cleaned with anhydrous ethanol. After drying with a hair dryer, it was placed in the sample stage and the vacuum chamber was closed for deposition.

[0042] The preparation process will be described through the following specific examples.

[0043] Example 1

[0044] (a) Using SUS304 stainless steel with a smooth surface free of oxides and scratches as the substrate, and 99.99% pure Nb and Y targets as the arc source, before the deposition process officially begins, the vacuum level in the deposition chamber is evacuated to 4 × 10⁻³ Pa using mechanical and molecular pumps. The magnetic field of the bent tube is 2.0 A, and the deposition temperature is 25 °C. When the FCVA equipment initiates the arc, the Y arc initiation current is first controlled at 90-120 A, the duty cycle is 90%, and the bias voltage is -800 V, -600 V, and -40 V. The voltage is decreased sequentially from 0V to -200V every 40 seconds. Then, the bias parameter is changed to -100V, and the duty cycle is adjusted to 30% for Y layer deposition for 50 seconds. After the Y layer is deposited, the Y arc is closed and the Nb arc is opened. The Nb arc starting current is set to 130A, the bias is kept at -100V, and the duty cycle is kept at 30% for Nb layer deposition for 40 seconds. Y layer 50s + Nb layer 40s = one cycle. The deposition is repeated for 15 cycles to obtain a uniformly distributed and strongly bonded Nb / Y nano metal multilayer film with Y and Nb layers.

[0045] (b) The deposited Nb / Y nano-metal multilayer film was subjected to high-temperature annealing. The Nb / Y nano-metal multilayer film was annealed at 800°C for one hour in an OTF-1200x tube furnace under a vacuum of 3×10-3 Pa. After cooling in the furnace, the Nb / Y nano-metal multilayer film deposition state and the cross section of the sample annealed at 800°C were observed by SEM.

[0046] from Figure 1 It can be seen that the Nb / Y nano-metal multilayer film modulation structure in Example 1 of the present invention is clear, the grains are columnar crystals that can improve the thermal stability of the system, the element distribution is uniform, and the structure is dense. Figure 2 It can be seen that after annealing at 800℃, the structure remains intact and the grain growth is appropriate. Figure 3The image shows a high-resolution TEM (HRTEM) microstructure of the sample annealed at 700℃, indicating that yttrium oxide with different structures was formed at the Nb layer interface. The transformation of yttrium oxide from a monoclinic structure to a cubic structure is beneficial to the reduction of the interface system energy and can inhibit the growth of Nb layer grains, thus maintaining the overall layered structure. Figure 4 for Figure 1 The red box shows the TEM-EDX elemental content table, which represents the bottommost bonding-enhancing transition layer. This transition layer is 150 nm thick and is a yttrium oxide + pure yttrium mixture formed by the reaction of yttrium with Y when oxygen content is low. It uniformly covers the substrate surface, enhancing the adhesion between the substrate and the film. From the oxygen atom percentage in Table 1, we can calculate the yttrium oxide percentage to be 9.41%. Since O is present in yttrium oxide, the relative yttrium oxide content is calculated as: O atomic percentage / (O atomic percentage + Y atomic percentage). The table contains a small amount of Nb because a small amount of Nb layer sputtered onto the transition layer during high-energy sputtering deposition enters the transition layer; this does not affect the accuracy of our analysis results. Comparative analysis with Examples 2 and 3 leads to the conclusion that a yttrium oxide content range of 7%-12% and a thickness of 100-200 nm in the transition layer yields the best results. Figure 3 c. Figure 3 d、 Figure 3 e and Figure 3 As can be seen from the comparison, the high-temperature resistant Nb / Y nano-metal multilayer film prepared by this invention exhibits excellent thermal stability at high temperatures. Its nanoindentation hardness also increases from 7.04 GPa in the deposited state to 8.95 GPa.

[0047] element mass percentage Atomic percentage % O 1.4 7.40 Y 75 71.17 Nb 23.6 21.43

[0048] Table 1

[0049] Example 2

[0050] All other conditions are the same as in Example 1, except that the transition layer thickness is adjusted to 50 nm. Figure 5 Based on the TEM-EDX elemental content table, we can calculate the yttrium oxide content as 2.23% from the percentage of O atoms in Table 2, which is not ideal.

[0051] element mass percentage Atomic percentage % O 0.39 2.13 Y 94.60 93.15 Nb 5.01 4.72

[0052] Table 2

[0053] Example 3

[0054] All other conditions are the same as in Example 1, except that the transition layer thickness is adjusted to 250 nm. Figure 6Based on the TEM-EDX elemental content table, we can calculate the yttrium oxide content as 15.1% from the percentage of O atoms in Table 3, which is not ideal.

[0055] element mass percentage Atomic percentage % O 2.39 12.10 Y 74.78 68.03 Nb 22.82 19.87

[0056] Table 3

[0057] Example 4

[0058] All other conditions are the same as in Example 1, except that the Y monolayer deposition time is adjusted to 20 s. Figure 7 The results showed that after annealing at 800°C for one hour, the film layer had cracked and the overall structure was destroyed.

[0059] Example 5

[0060] Other conditions are the same as in Example 1, except that the Y monolayer deposition time is adjusted to 80 seconds, and after annealing at 800°C for one hour... Figure 8 It shows obvious grain growth and destruction of the layered modulation structure.

[0061] Example 6, with all other conditions the same as Example 1, except that the deposition time of the Y layer was 120 s, and after annealing at 800℃ for one hour, Figure 9 The Y layer is intact, but the Nb layer structure is damaged, and the overall modulation structure fails.

[0062] Comparative Example 1

[0063] Using SUS304 stainless steel with a smooth surface free of oxides and scratches as the substrate, and Zr and Y targets with a purity of 99.99% as the arc source, the vacuum level in the deposition chamber was evacuated to 4 × 10⁻³ Pa using mechanical and molecular pumps before the deposition process began. The bending magnetic field was 2.0 A, the deposition temperature was 25 °C, the Y-arc ignition current was 90-120 A, the duty cycle was 90%, and the bias voltage was -800 V, -600 V, -400 V, and -2 V. The bias voltage was gradually decreased from 0.0V every 40 seconds, then changed to -100V, and the duty cycle was adjusted to 30% for Y-layer deposition for 17 seconds. After the Y-layer was deposited, the Y-arc was closed and the Zr arc was opened. The Zr arc starting current was set to 130A, the bias voltage was maintained at -100V, and the duty cycle was maintained at 30% for Zr layer deposition for 20 seconds. One cycle consisted of 17 seconds for Y-layer deposition and 20 seconds for Zr layer deposition. This process was repeated 20 times to obtain a Zr / Y nanoscale metal multilayer film with uniformly distributed Y and Zr layers. The Zr / Y multilayer film was then subjected to vacuum annealing at 800℃ for one hour, consistent with Example 1. Figure 10As can be seen, the layered structure composed of Zr and Y layers in the multilayer film mostly maintains its structure, with only a small portion showing structural damage. However, compared to the Nb / Y nano-metal multilayer film in Example 1, the thermal stability of the Zr / Y nano-metal multilayer film in Comparative Example 1 is significantly worse.

[0064] Comparative Example 2

[0065] Other conditions were the same as in Comparative Example 1, with Zr deposition time of 25 s and Y deposition time of 40 s, followed by vacuum annealing at 800 °C for one hour. Figure 11 The Zr and Y layers in the middle layer are mutually soluble, and the layered modulation structure is destroyed.

[0066] Comparative Example 3

[0067] Other conditions were the same as in Comparative Example 1: the Y-layer arc current was 120 A, the Y deposition time was 67 s, the Zr deposition time was 80 s, and the mixture was annealed in a vacuum at 800 °C for one hour. Figure 12 The Zr and Y layers in the middle layer are completely destroyed, and the grains grow in a disordered manner.

[0068] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0069] In this document, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, which includes not only the elements listed but also other elements not expressly listed.

[0070] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing a controllable oxidation high-performance nano-metal multilayer film, characterized in that, The preparation method includes: Using stainless steel as a substrate and yttrium target as an arc source, yttrium deposition is performed on the substrate based on the yttrium arc to obtain a transition layer containing yttrium oxide and yttrium. The thickness of the transition layer is 100-200 nm, and the yttrium oxide content in the transition layer is in the range of 7%-12%. Yttrium deposition is performed on the transition layer using a yttrium arc to obtain a yttrium layer; Using a niobium target as an electric arc source, niobium is deposited on the yttrium layer based on the niobium arc to obtain a niobium layer; Using one yttrium layer and one niobium layer as a cycle layer, N cycles are repeated to obtain a controllable oxidation high-performance nano-metal multilayer film containing a transition layer and N cycle layers, wherein 10 ≤ N ≤ 50.

2. The method for preparing a controllable oxidation high-performance nano-metal multilayer film according to claim 1, characterized in that, Before obtaining a transition layer containing yttrium oxide and yttrium on the substrate using a stainless steel substrate and a yttrium target as an arc source, the process includes: The vacuum level in the deposition chamber was evacuated to 4 × 10⁻⁴ using both mechanical and molecular pumps. -2 Pa-4×10 -3 Pa, the bending magnetic field is 2.0A, the deposition temperature is 25℃, and when the FCVA equipment starts the arc, the Y arc starting current is first controlled to be 90-120A, the duty cycle is 90%, and the bias voltage is -800V, -600V, -400V, -200V decreasing sequentially every 40s.

3. The method for preparing a controllable oxidation high-performance nano-metal multilayer film according to claim 2, characterized in that, The method of using stainless steel as a substrate, yttrium target as an arc source, and performing yttrium deposition on the substrate based on a yttrium arc to obtain a transition layer containing yttrium oxide and yttrium includes: Using stainless steel as a substrate, a yttrium target is used as an arc source with a bias voltage of -100V and a duty cycle of 30% for yttrium deposition. Yttrium reacts with residual oxygen on the substrate surface to generate a yttrium oxide thin layer. The yttrium oxide thin layer forms chemical bonds with the substrate to obtain a transition layer containing yttrium oxide and yttrium.

4. The method for preparing a controllable oxidation high-performance nano-metal multilayer film according to claim 2, characterized in that, The method of using a niobium target as an electric arc source to deposit niobium on the yttrium layer to obtain a niobium layer includes: On the yttrium layer, a niobium target is used as an arc source, the niobium arc ignition current is set to 130A, the bias voltage is kept at -100V, and the duty cycle is kept at 30% to deposit the niobium layer.

5. The method for preparing a controllable oxidation high-performance nano-metal multilayer film according to claim 2, characterized in that, After repeating the process of using one yttrium layer and one niobium layer as a cycle as a loop layer, and repeating N cycles to obtain a controllable oxidation high-performance nano-metal multilayer film containing a transition layer and N loop layers, the process further includes: The controllable oxidation high-performance nano-metal multilayer film was placed in a tube furnace and annealed at 800°C for one hour under a vacuum of 3×10-3 Pa, followed by furnace cooling.

6. A controllable oxidation high-performance nano-metal multilayer film prepared by the method for preparing a controllable oxidation high-performance nano-metal multilayer film according to any one of claims 1-5, characterized in that, include: A transition layer, a yttrium layer, and a niobium layer are sequentially grown on a stainless steel substrate; the transition layer comprises yttrium oxide and yttrium, wherein the thickness of the transition layer is 100-200 nm, and the yttrium oxide content in the transition layer ranges from 7% to 12%; Using one yttrium layer and one niobium layer as a cycle layer, N cycles are repeated to obtain a controllable oxidation high-performance nano-metal multilayer film containing a transition layer and N cycle layers, wherein 10 ≤ N ≤ 50.

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