Surface treatment process of high-temperature superconducting foil tape N10276
By employing shot blasting, composite pickling, multi-stage grinding, and texturing rolling processes, the problems of hot-rolled oxidation defects and surface quality of ultra-thin foil strips in N10276 alloy were solved, achieving high surface quality treatment of high-temperature superconducting foil strips.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- 江苏圣珀新材料科技有限公司
- Filing Date
- 2026-02-26
- Publication Date
- 2026-05-05
AI Technical Summary
Existing processes cannot completely eliminate the hot-rolled oxidation defects of N10276 alloy, nor can they achieve high surface quality treatment of ultra-thin foil strips, resulting in unqualified surface roughness and oxide scale indentation defects.
The process employs a multi-stage collaborative design involving shot blasting to break up the oxide layer, composite pickling, multi-stage grinding, and texturing rolling. This includes shot blasting to break up the oxide layer, pickling with a pickling solution of a specific formula, flexible grinding with abrasive belts and flap wheels, and finally rolling with laser texturing rolls.
Completely remove oxide scale indentation defects to obtain a superconducting foil with a bright, uniform surface and high consistency, with a roughness Ra≤0.05μm, meeting production requirements.
Smart Images
Figure CN121972525A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of foil processing technology, specifically to a surface treatment process for high-temperature superconducting foil N10276. Background Technology
[0002] Second-generation high-temperature superconducting (2G-HTS) tapes typically employ a structure where multiple functional thin films are deposited on a metal substrate (such as Hastelloy N10276). The surface quality (roughness, cleanliness, and uniformity) of the N10276 foil, serving as the base tape, directly determines the quality of the epitaxially grown buffer layer and superconducting layer, thus affecting the critical current density of the final superconducting tape. Typically, a surface roughness Ra ≤ 0.05 μm is required, with no oxide scale, indentations, or other defects.
[0003] N10276 alloy is a high-nickel, chromium, molybdenum, and tungsten alloy with extremely high high-temperature strength and good oxidation resistance. This means that conventional high-pressure water descaling processes cannot be used during hot rolling to prevent excessive temperature drop. Consequently, a thick and dense composite oxide layer of Cr2O3, NiO, etc., forms on the surface of the strip after hot rolling, and some of this layer is pressed into the substrate under the rolling force, forming an oxide scale indentation defect. Traditional single pickling or mechanical polishing methods are insufficient to completely remove this defect. Furthermore, when the strip is rolled to ultra-thin specifications of 0.046mm or even thinner, its rigidity is extremely low, making effective direct surface treatment with traditional wire drawing and sanding equipment impossible, and strip breakage and wrinkling are highly likely. Summary of the Invention
[0004] The purpose of this invention is to provide a surface treatment process for high-temperature superconducting foil N10276 in order to solve the problems that existing processes cannot completely eliminate the hot rolling oxidation defects of N10276 alloy and cannot achieve high surface quality surface treatment forming of ultra-thin foil strips.
[0005] To achieve the above objectives, the present invention adopts the following technical solution: a surface treatment process for high-temperature superconducting foil N10276, comprising the following steps:
[0006] S1. Shot blasting to break the oxide layer: The hot-rolled N10276 alloy strip is shot blasted to break the dense oxide layer on its surface and spacers are placed between the strip layers.
[0007] S2. Composite pickling: The shot-blasted strip is immersed in pickling solution and pickled at a set temperature and pickling time.
[0008] The pickling solution contains sulfuric acid, sodium chloride, and sodium nitrate;
[0009] S3. Multi-stage grinding: The pickled semi-finished strip is ground sequentially using multiple sets of abrasive belts and then finely polished;
[0010] S4. Textured rolling: In the process of finally cold rolling the ground strip to a target thickness of less than or equal to 0.046 mm, rolling is performed using rolls with laser-textured surfaces.
[0011] As a further description of the above technical solution:
[0012] In step S1, the shot used in the shot blasting process is stainless steel wire cut shot or cast steel shot, with a particle size of 0.2-0.6 mm and a shot blasting intensity of 0.10-0.25 mmN.
[0013] As a further description of the above technical solution:
[0014] In step S1, the spacer is an iron wire or a stainless steel wire with a diameter of 0.1-0.5 mm.
[0015] As a further description of the above technical solution:
[0016] In step S2, the set temperature is 60-90℃, the set pickling time is 30-90 minutes, and the pickling solution contains 130-140 ml of 98% sulfuric acid, 70-80 g of sodium chloride, and 70-80 g of sodium nitrate per liter of water.
[0017] As a further description of the above technical solution:
[0018] In step S3, the abrasive belts include a combination of 80-mesh and 120-mesh abrasive belts used in the first stage of grinding and a combination of 120-mesh and 180-mesh abrasive belts used in the second stage of grinding. Each stage of abrasive belt grinding is followed by fine polishing using a flap wheel.
[0019] As a further description of the above technical solution:
[0020] The flap wheel is made of nylon or a composite material containing silicon carbide and alumina abrasives.
[0021] As a further description of the above technical solution:
[0022] In step S4, the surface roughness Ra of the roll is 2.8-3.2 μm, and the density of its roughening pits is 50-200 pits / cm².
[0023] As a further description of the above technical solution:
[0024] During the rolling process in step S4, the tension of the strip is controlled, with the tension range being 10%-30% of the yield strength of the foil strip N10276, and lubrication and cooling are carried out in conjunction with rolling oil.
[0025] In summary, due to the adoption of the above technical solution, the present invention has the following beneficial effects compared with the prior art:
[0026] The surface treatment process of this invention, tailored to the characteristics of N10276 material, employs a multi-step collaborative design involving shot blasting to break the oxide layer, composite pickling, multi-stage grinding, and texturing rolling to thoroughly remove stubborn oxide scale indentation defects. Specifically, shot blasting breaks down the oxide layer on the strip surface to increase its exposed area, thereby increasing the efficiency of subsequent pickling without causing severe impact on the N10276 foil body, ensuring its quality. Pickling with a pickling solution composed of sulfuric acid, sodium chloride, and sodium nitrate in a specific ratio improves the oxide layer removal effect. After pickling, a flexible grinding method combining abrasive belts and flap wheels is used to deeply eliminate residual oxide scale indentation defects and remove abrasive belt scratches. Finally, the foil is rolled using laser texturing rolls, thus solving production challenges such as the inability to polish ultra-thin strips, the difficulty in removing surface enrichment layers, and the extremely high requirements for surface consistency. The final N10276 superconducting foil strip has a bright and uniform surface with high consistency, a roughness Ra≤0.05μm, and no oxidation residues or enrichment layer defects, meeting its production and use requirements. Attached Figure Description
[0027] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0028] Figure 1 This is a flowchart of a surface treatment process for high-temperature superconducting foil N10276.
[0029] Figure 2 This is a photograph of the N10276 alloy strip before shot blasting in step S1, as part of a surface treatment process for a high-temperature superconducting foil strip N10276.
[0030] Figure 3 This is a photograph of the surface treatment process of high-temperature superconducting foil N10276 after shot blasting in step S1.
[0031] Figure 4 This is a photograph of the N10276 high-temperature superconducting foil after the pickling process in step S2, which is a surface treatment process for the N10276 high-temperature superconducting foil.
[0032] Figure 5 This is a photograph of the N10276 high-temperature superconducting foil after grinding in step S3, as part of a surface treatment process.
[0033] Figure 6 This is a physical image of the rolls and strip during the rolling process in step S4 of a surface treatment process for high-temperature superconducting foil strip N10276.
[0034] Figure 7 The surface treatment process of high-temperature superconducting foil N10276 is shown in step S4, after rolling. The actual product of foil N10276 is shown. Figure 1 .
[0035] Figure 8 The surface treatment process of high-temperature superconducting foil N10276 is shown in step S4, after rolling. The actual product of foil N10276 is shown. Figure 2 . Detailed Implementation
[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.
[0037] Therefore, the following detailed description of the embodiments of the 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 invention without inventive effort are within the scope of protection of the invention.
[0038] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.
[0039] In the description of the embodiments of the present invention, it should be noted that the terms "upper" and "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the present invention.
[0040] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection, an indirect connection through an intermediate medium, or a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.
[0041] Example 1:
[0042] Please see Figure 1-8 This invention provides a technical solution: a surface treatment process for high-temperature superconducting foil N10276. In this embodiment, the process is used to treat hot-rolled N10276 alloy strip coils, eliminating defects such as the oxide layer on its surface, and rolling it into a foil strip with a thickness of 0.046 mm and a surface roughness Ra ≤ 0.05 μm to form a product that meets customer requirements. The specific steps include:
[0043] Because N10276 alloy material turns blackish-green after hot rolling, its surface has a dense oxide layer, accompanied by the indentation of oxide scale during hot rolling, specifically as follows... Figure 2 As shown, the oxide layer needs to be removed first.
[0044] S1. Shot blasting to break the oxide layer: The hot-rolled N10276 alloy strip is shot blasted to break the dense oxide layer on its surface and spacers are placed between the strip layers; the spacers separate the strip, facilitating further surface treatment; the changes in the strip before and after shot blasting are as follows. Figure 2 , 3 As shown;
[0045] The purpose of shot blasting in this step is not to directly remove the oxide layer, but to use the impact force of high-speed shot to break up the dense and complete oxide layer, generating a large number of microcracks, which greatly increases the contact reaction area for subsequent pickling. To prevent the strip from sticking together due to oxide powder during shot blasting and subsequent stacking, spacers are added between the strip layers.
[0046] S2. Composite pickling: The shot-blasted strip is immersed in pickling solution and pickled at a set temperature and pickling time.
[0047] The pickling solution contains sulfuric acid, sodium chloride, and sodium nitrate;
[0048] Specifically, in step S2, the set temperature is 60-90℃, the set pickling time is 30-90 minutes, and the pickling solution, per liter of water, contains 130-140 ml of 98% sulfuric acid, 70-80 g of sodium chloride, and 70-80 g of sodium nitrate. Preferably, it contains 135 ml of 98% sulfuric acid, 73 g of salt (i.e., sodium chloride), and 73 g of sodium nitrate. See the table below:
[0049]
[0050] The pickling time is based on the actual removal of oxide scale (the strip surface turns white). At this point, some of the oxide scale and most of the oxide scale have been removed. The pickled strip looks like... Figure 4 As shown.
[0051] The strip is pickled using a hot pickling solution with the specific formulation described above. The pickling solution uses a sulfuric acid-sodium chloride-sodium nitrate system. Sulfuric acid (H2SO4) is the main solvent; the addition of sodium chloride (NaCl) allows its Cl- ions to destroy the passivation film of chromium oxide (Cr2O3), significantly accelerating the erosion of the dense oxide layer; sodium nitrate (NaNO3), as an oxidant, can inhibit the over-corrosion of the base metal by the acid solution and promote the dissolution of certain low-valence oxides, making the pickled surface more uniform and bright.
[0052] After pickling, most of the oxide scale is removed, but a very small amount of deep indentation may remain. Therefore, the semi-finished strip is mechanically ground.
[0053] S3. Multi-stage grinding: The pickled semi-finished strip is ground sequentially using multiple sets of abrasive belts and then finely polished;
[0054] In step S3, the abrasive belt includes an abrasive belt with a combination of 80 mesh and 120 mesh used in the first stage of grinding, and an abrasive belt with a combination of 120 mesh and 180 mesh used in the second stage of grinding. After each stage of abrasive belt grinding, a flap wheel is used for fine polishing.
[0055] Multi-stage grinding is achieved using multiple sets of abrasive belts with gradually increasing grit, combined with a flap wheel for surface treatment of the material, thoroughly removing residual oxide scale and oxidized material. A flexible grinding method combining abrasive belts and flap wheels is employed. First, a combination of 80-grit (coarse) and 120-grit (medium) abrasive belts is used to remove macroscopic unevenness; then, a combination of 120-grit (medium) and 180-grit (fine) abrasive belts is used to further improve the surface finish. After each belt change, a flap wheel is used for auxiliary polishing. The flexibility of the flap wheel allows it to conform to the strip surface, removing abrasive belt marks and preparing for the next process. This step is performed when the strip still has sufficient thickness and strength, avoiding the difficulties of processing thin strips.
[0056] S4. Textured rolling: In the process of finally cold rolling the ground strip to a target thickness of less than or equal to 0.046 mm, rolling is performed using rolls with laser-textured surfaces.
[0057] In step S4, the surface roughness Ra of the roll is 2.8-3.2 μm, preferably about 2.973 μm, and the density of its roughening pits is 50-200 pits / cm².
[0058] During the heat treatment of high-nickel materials, the surface is prone to enrichment of C, O, and N, resulting in a bluish tint. Figure 5 As shown, materials with a thickness below 0.35mm are generally beyond the surface treatment capabilities of wire drawing equipment. Therefore, laser texturing rolls are used in the cold rolling process, such as... Figure 6 As shown, the material is rolled, and the surface after rolling is uniform and consistent, meeting the material surface requirements without any abnormalities. The rolled foil strip is as follows. Figure 7 As shown, and Figure 8 This image shows the finished product of the foil strip after subsequent processing. This process ensures excellent consistency in the finished foil strip. The final rolling is performed using laser-textured rolls. The roll surface is laser-dispersed and roughened to form a uniform and controllable array of micro-pits. During rolling, the microscopic morphology of the roll surface assists in shaping the foil strip surface. This process has multiple benefits: First, the uniform micro-morphology makes the rolling oil film more stable, improving lubrication and reducing friction and surface scratches; second, the rolling force causes micro-plastic flow of the surface metal of the foil strip, effectively breaking down or dispersing any possible trace enrichment layers; third, a uniform and controllable matte surface is ultimately formed on the foil strip, with an extremely low roughness Ra value (≤0.05μm) and extremely high consistency, fully meeting the requirements for epitaxial growth of superconducting thin films and fundamentally avoiding the technical bottleneck of not being able to perform independent final polishing of ultrathin foil strips.
[0059] Example 2:
[0060] Please see Figure 1-3 The figure illustrates a surface treatment process for high-temperature superconducting foil N10276 provided in Embodiment 2 of the present invention. Based on the above embodiments, this embodiment further improves upon the following technical solutions: In step S1, the shot used in the shot blasting process is stainless steel wire shot or cast steel shot, with a particle size of 0.2-0.6 mm, preferably 0.3 mm, and a shot blasting intensity of 0.10-0.25 mmN, preferably 0.18 mmN, to achieve the effect of breaking the film without severely impacting the metal substrate. Through the design of the above shot blasting process parameters, the shot blasting quality is further improved.
[0061] In step S1, the spacer is made of iron wire or stainless steel wire with a diameter of 0.1-0.5 mm, preferably 0.2 mm. This ensures the separation of the strip while avoiding significant impact of the spacer on the subsequent processing of the entire surface of the strip.
[0062] Example 3:
[0063] Please see Figure 1 , 5 The figure illustrates a surface treatment process for high-temperature superconducting foil N10276 provided in Embodiment 3 of the present invention. This embodiment further improves upon the above embodiments by employing the following technical solution: the flap wheel is made of nylon or a composite material containing silicon carbide and alumina abrasives. This improves the quality of fine polishing.
[0064] Example 4:
[0065] Please see Figure 1 , 6 Figure -8 illustrates a surface treatment process for high-temperature superconducting foil N10276 provided in Embodiment 4 of the present invention. Based on the above embodiments, this embodiment further improves upon the following technical solutions: During the rolling process in step S4, tension control is applied to the strip, with the tension range being 10%-30% of the yield strength of the foil N10276, specifically 10-15 MPa. Lubrication and cooling are performed using rolling oil, ultimately rolling to a thickness of 0.046 mm. Micro-tension control (e.g., 15% of the foil's yield strength) and specialized rolling oil are employed to ensure rolling stability and surface quality.
[0066] Based on the surface treatment process design of the above embodiments, when inspecting the finished product, a surface profilometer is used to measure the surface roughness of the foil strip. The Ra value is 0.03-0.04 μm, and the measured value fluctuates very little at different locations. Under a metallographic microscope, no oxide scale is indented on the surface, no bluing phenomenon is observed, and the microstructure is uniform.
[0067] In summary, due to the adoption of the above technical solutions, the surface treatment process of high-temperature superconducting foil N10276 in this embodiment has the following advantages compared with the prior art:
[0068] The surface treatment process of this invention, tailored to the characteristics of N10276 material, employs a multi-step collaborative design involving shot blasting to break the oxide layer, composite pickling, multi-stage grinding, and texturing rolling to thoroughly remove stubborn oxide scale indentation defects. Specifically, shot blasting breaks down the oxide layer on the strip surface to increase its exposed area, thereby increasing the efficiency of subsequent pickling without causing severe impact on the N10276 foil body, ensuring its quality. Pickling with a pickling solution composed of sulfuric acid, sodium chloride, and sodium nitrate in a specific ratio improves the oxide layer removal effect. After pickling, a flexible grinding method combining abrasive belts and flap wheels is used to deeply eliminate residual oxide scale indentation defects and remove abrasive belt scratches. Finally, the foil is rolled using laser texturing rolls, thus solving production challenges such as the inability to polish ultra-thin strips, the difficulty in removing surface enrichment layers, and the extremely high requirements for surface consistency. The final N10276 superconducting foil strip has a bright and uniform surface with high consistency, a roughness Ra≤0.05μm, and no oxidation residues or enrichment layer defects, meeting its production and use requirements.
[0069] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.
Claims
1. A surface treatment process for high-temperature superconducting foil N10276, characterized in that, Includes the following steps: S1. Shot blasting to break the oxide layer: The hot-rolled N10276 alloy strip is shot blasted to break the dense oxide layer on its surface and spacers are placed between the strip layers. S2. Composite pickling: The shot-blasted strip is immersed in pickling solution and pickled at a set temperature and pickling time. The pickling solution contains sulfuric acid, sodium chloride, and sodium nitrate; S3. Multi-stage grinding: The pickled semi-finished strip is ground sequentially using multiple sets of abrasive belts and then finely polished; S4. Textured rolling: In the process of finally cold rolling the ground strip to a target thickness of less than or equal to 0.046 mm, rolling is performed using rolls with laser-textured surfaces.
2. The surface treatment process for high-temperature superconducting foil N10276 according to claim 1, characterized in that, In step S1, the shot used in the shot blasting process is stainless steel wire cut shot or cast steel shot, with a particle size of 0.2-0.6 mm and a shot blasting intensity of 0.10-0.25 mmN.
3. The surface treatment process for high-temperature superconducting foil N10276 according to claim 1, characterized in that, In step S1, the spacer is an iron wire or a stainless steel wire with a diameter of 0.1-0.5 mm.
4. The surface treatment process for high-temperature superconducting foil N10276 according to claim 1, characterized in that, In step S2, the set temperature is 60-90℃, the set pickling time is 30-90 minutes, and the pickling solution contains 130-140 ml of 98% sulfuric acid, 70-80 g of sodium chloride, and 70-80 g of sodium nitrate per liter of water.
5. The surface treatment process for high-temperature superconducting foil N10276 according to claim 1, characterized in that, In step S3, the abrasive belts include a combination of 80-mesh and 120-mesh abrasive belts used in the first stage of grinding and a combination of 120-mesh and 180-mesh abrasive belts used in the second stage of grinding. Each stage of abrasive belt grinding is followed by fine polishing using a flap wheel.
6. The surface treatment process for high-temperature superconducting foil N10276 according to claim 5, characterized in that, The flap wheel is made of nylon or a composite material containing silicon carbide and alumina abrasives.
7. The surface treatment process for high-temperature superconducting foil N10276 according to claim 1, characterized in that, In step S4, the surface roughness Ra of the roll is 2.8-3.2 μm, and the density of its roughening pits is 50-200 pits / cm².
8. The surface treatment process for high-temperature superconducting foil N10276 according to claim 1, characterized in that, During the rolling process in step S4, the tension of the strip is controlled, with the tension range being 10%-30% of the yield strength of the foil strip N10276, and lubrication and cooling are carried out in conjunction with rolling oil.