Composite superconductor and method for manufacturing the same

Abstract

To provide a composite superconductor of various shapes with an increased ratio of superconductor, and a method for producing the superconductor.SOLUTION: A method for producing a composite superconductor 300 that has an area in which a metal thin layer 32a and a superconductor layer 14 are laminated, and includes two layers or more of the metal thin layers 32a and the superconductor layers 14. The method includes polishing at least a part of a surface 12S of an unpolished metal layer 12, which is the opposite side of the superconductor layer 14 of an unpolished laminate layer 11 including the unpolished metal layer 12 and the superconductor layer 14 formed on the unpolished metal layer 12, and forming a unit lamination region 30R including the metal thin layer 32a and the superconductor layer 14 formed on the metal thin layer 32a.SELECTED DRAWING: Figure 2

Description

【Technical Field】 【0001】 The present invention relates to a composite superconductor and a method for manufacturing the same. 【Background Art】 【0002】 Superconductivity can be used in transportation fields such as linear motor cars, medical fields represented by MRI, processing fields such as superconducting-assisted processing, and energy transportation technologies (for example, Patent Document 1). 【0003】 As superconducting materials, superconducting bulks and superconducting wirings are known. A superconducting bulk can have the entire bulk as a superconductor, but on the other hand, it tends to have low brittleness and weak pinning. As superconducting wirings, superconducting wire materials such as Fujikura wires have been developed (for example, Patent Document 2). Since the superconducting wire material is a metal, it is easy to bend and has excellent workability compared to the superconducting bulk. In addition, it can exhibit strong pinning. Taking advantage of such advantages, the superconducting wire material has the potential to replace the superconducting bulk in all areas where the superconducting bulk has been put into practical use. 【Prior Art Documents】 【Patent Documents】 【0004】 【Patent Document 1】 Japanese Patent Application Laid-Open No. 2017-094442 【Patent Document 2】 Japanese Patent No. 6919042 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0005】 In a superconducting wire material, a superconductor layer or the like is formed on a metal film (metal substrate). However, the superconductor layer is thin with respect to the metal film, for example, about 1 / 100, and is not efficient. Therefore, it has been required to increase the proportion of the superconductor. Under these circumstances, the object of the present invention is to provide composite superconductors of various shapes with an increased proportion of superconductors, and a method for manufacturing the same. [Means for solving the problem] 【0006】 The inventors of this invention have conducted extensive research to solve the above problems and have found that the following invention is suitable for the above purpose, leading to the present invention. That is, the present invention relates to the following invention. 【0007】 <1> A method for manufacturing a composite superconductor having a portion in which a thin metal layer and a superconductor layer are laminated, and comprising two or more layers each of the thin metal layer and the superconductor layer, comprising polishing at least a portion of the surface of the unpolished metal layer opposite to the superconductor layer of an unpolished laminate comprising an unpolished metal layer and a superconductor layer formed on the unpolished metal layer, thereby forming a unit laminate region comprising a thin metal layer including the polished metal layer and the superconductor layer formed on the thin metal layer. <2> The polishing is dry polishing, <1> A method for manufacturing the composite superconductor described above. <3> Furthermore, the method includes forming a multilayer structure in which two or more unit stacking regions are stacked alternately, such that the metal thin layer and the superconductor layer are alternately arranged. <1> or <2> A method for manufacturing a composite superconductor as described above. <4> The polishing step A involves polishing at least a portion of the surface of the unpolished metal layer of the unpolished laminate that is opposite to the superconductor layer to obtain a laminate having the unit stacking region, and the stacking step involves stacking the laminates obtained in the polishing step A so that the metal thin layer and the superconductor layer are alternately arranged to form a multi-layer structure. <1> from <3> A method for manufacturing a composite superconductor as described in any of the following. <5> The process includes a winding step of winding the unpolished laminate around a core material so that the unpolished metal layer faces outwards, and a polishing step B of polishing at least a portion of the outer surface of the unpolished laminate wound around the core material. <1> from <3> A method for manufacturing a composite superconductor as described in any of the following. <6> The method for manufacturing a composite superconductor according to <5>, wherein the winding process and the polishing process B are repeated to form a multi-layer structure. <7> The method for manufacturing a composite superconductor according to <6>, wherein at least a part of the outer surface of the unpolished laminate wound around the core material is polished while winding a part of the unpolished laminate around the core material so that the unpolished metal layer is on the outside. <8> The method for manufacturing a composite superconductor according to any one of <1> to <3>, wherein a unit laminate region formed by polishing at least a part of the surface of the unpolished metal layer of the unpolished laminate on the side opposite to the superconductor layer is wound around a core material to form a multi-layer structure. <9> In the unit laminate region, the thickness of the superconductor layer is t s and the thickness of the metal thin layer is t m When, 0.1 × t s ≦ t m ≦ 3 × t s The method for manufacturing a composite superconductor according to any one of <1> to <8>, wherein polishing is performed so that this relationship holds. <10> The method for manufacturing a composite superconductor according to any one of <1> to <9>, wherein polishing is performed so that the average roughness Ra of the polished surface is 0.1 μm or less. 【0008】 <11> A composite superconductor having a portion where a metal thin layer and a superconductor layer are laminated, and including two or more layers of each of the metal thin layer and the superconductor layer. When the thickness of the superconductor layer is t s and the thickness of the metal thin layer is t m When, 0.1 × t s ≦ t m ≦ 3 × t s And the average roughness Ra of at least one surface of the metal thin layer is 0.1 μm or less. <12> The composite superconductor according to <11>, having a portion with a multi-layer structure in which the metal thin layer and the superconductor layer are alternately laminated two or more layers each. <13> A laminate having a unit stacking region including the metal thin layer and the superconductor layer formed on the metal thin layer, and a core material, wherein the unit stacking region is a portion in which the metal thin layer and the superconductor layer are stacked, and the laminate covers at least a portion of the surface of the core material. <11> or <12> The composite superconductor described above. <14> A composite superconductor comprising a rectangular parallelepiped core material and a laminate wrapped around the core material, wherein the laminate includes a metal layer and a superconducting layer formed on the metal layer, and the metal layer of the laminate has a thickness in the portion covering two opposing faces having the largest surface area of ​​the core material that is thinner than the thickness in the portion covering the other face. [Effects of the Invention] 【0009】 The present invention provides a composite superconductor with an increased proportion of superconductors and a method for manufacturing the same. According to the manufacturing method of the present invention, composite superconductors of various shapes with an increased proportion of superconductors can be easily manufactured. [Brief explanation of the drawing] 【0010】 [Figure 1] This is a diagram illustrating an example of the manufacturing method of the present invention. [Figure 2] This is a diagram illustrating an example of the manufacturing method of the present invention. [Figure 3] This is an example of a composite superconductor manufactured by the manufacturing method of the present invention. [Figure 4] This is a diagram illustrating an example of the manufacturing method of the present invention. [Figure 5] This is an example of a composite superconductor manufactured by the manufacturing method of the present invention. [Figure 6] This is an example of a composite superconductor manufactured by the manufacturing method of the present invention. [Figure 7] This figure shows the levitation experiment of a magnet using a superconductor in Example 1. [Figure 8] This figure shows the levitation experiment of a magnet using a superconductor in Comparative Example 1. [Modes for carrying out the invention] 【0011】 The embodiments of the present invention will be described in detail below, but the description of the constituent elements described below is just one example (representative example) of the embodiments of the present invention, and the present invention is not limited to the following unless its gist is changed. In this specification, when the expression "~" is used, it is used to mean an expression that includes the numerical value or physical property value before and after it. 【0012】 <Method for manufacturing composite superconductors> The present invention relates to a method for manufacturing a composite superconductor having a portion in which a thin metal layer and a superconductor layer are laminated, and which includes two or more thin metal layers and superconductor layers, comprising polishing at least a portion of the surface of the unpolished metal layer opposite to the superconductor layer of an unpolished laminate including an unpolished metal layer and a superconductor layer formed on the unpolished metal layer, thereby forming a unit laminate region including a thin metal layer containing a polished metal layer and a superconductor layer formed on the thin metal layer (hereinafter sometimes referred to as "the manufacturing method of the present invention"). 【0013】 In this way, the proportion of superconductors can be easily increased by polishing the unpolished metal layer of the unpolished laminate. The resulting composite superconductor can efficiently exhibit superconducting properties and improve magnetic susceptibility. Furthermore, the manufacturing method of the present invention is also excellent in terms of processability, and the processed shape can be diverse. 【0014】 In other words, because the base metal layer can be made extremely thin, the proportion of superconducting layers (proportion of superconducting material) in the stacked (several to several thousand layers) composite superconductors is dramatically improved, resulting in improved superconducting properties. Therefore, composite superconductors obtained by the manufacturing method of the present invention can achieve a dramatic improvement in properties compared to conventional composite superconductors of the same thickness without polishing the metal layer. 【0015】 The manufacturing method of the present invention provides a composite superconductor having a portion in which a thin metal layer and a superconductor layer are laminated, and which contains two or more layers each of the thin metal layer and the superconductor layer. The unit laminated region formed by polishing the unpolished laminate becomes the portion in which the thin metal layer and the superconductor layer are laminated. The thin metal layer can be formed by polishing the unpolished metal layer of the unpolished laminate, as described later, for example, by setting the thickness of the superconductor layer to t s , the thickness of the thin metal layer m In this case, 0.1 × t s ≤t m ≤3 × t s The average roughness Ra of the metal thin layer on the opposite side of the superconductor layer is 0.1 μm or less. 【0016】 For example, a composite superconductor in which a thin metal layer and a superconducting layer are stacked, and each of the thin metal layer and the superconducting layer contains two or more layers, and the thickness of the superconducting layer is t s , the thickness of the thin metal layer m In this case, 0.1 × t s ≤t m ≤3 × t s Thus, a composite superconductor can be obtained with an average roughness Ra of 0.1 μm or less on at least one surface of the metal thin layer. More preferably, 0.1 × t s ≤t m ≤t s The composite superconductor is characterized by having an average roughness Ra of at least one of the metal thin layers of 0.1 μm or less. Such composite superconductors are preferred because they have a high proportion of superconductors and readily exhibit superconducting properties. 【0017】 Furthermore, the manufactured composite superconductor contains two or more layers each of metal thin layers and superconductor layers. For example, it can have a multi-layer structure with a total of four or more layers, where two or more layers each of metal thin layers and superconductor layers are stacked alternately. Also, since the composite superconductor only needs to contain two or more layers each of metal thin layers and superconductor layers in a certain direction such as the thickness direction, it may have a configuration in which a portion (for example, a unit stack region) of one layer of metal thin layer and one layer of superconductor layer are stacked above and below the core material. The metal thin layers and superconductor layers may be stacked via another layer other than the metal thin layers and superconductor layers. In a multi-layer structure with a total of four or more layers, where two or more layers each of metal thin layers and superconductor layers are stacked alternately, it is sufficient that the metal thin layers and superconductor layers are arranged alternately when viewed from the perspective of the metal thin layers and superconductor layers, even if the configuration includes another layer other than the metal thin layers and superconductor layers. 【0018】 [Unpolished laminate] The unpolished laminate used in the manufacturing method of the present invention includes an unpolished metal layer and a superconductor layer formed on the unpolished metal layer. The unpolished laminate can be in the form of a film, sheet, wire, etc., and its thickness is approximately 5.5 to 210 μm. The unpolished metal layer is preferably composed of a non-magnetic metal or alloy material, for example, a nickel alloy or a copper alloy. The thickness of the unpolished metal layer is approximately 5.0 to 200 μm. The superconductor layer is a layer formed on the unpolished metal layer and can be formed of metal oxides such as GBCO and YBCO, or graphite materials such as fullerene. The method for forming the superconductor layer is not particularly limited and can be formed by methods such as sputtering or vacuum thin film formation techniques such as vapor deposition. The thickness of the superconductor layer is approximately 0.5 to 10 μm. Furthermore, the unpolished laminate may include layers other than the unpolished metal layer and the superconductor layer. For example, it may include layers such as an adhesion-enhancing layer (ceramic material or a metal material different from the material constituting the unpolished metal layer) to strengthen the adhesion between the unpolished metal layer and the superconductor layer, or a strength-enhancing layer (ceramic material or a metal material different from the material constituting the unpolished metal layer) to improve the strength and flexibility of the composite superconductor. However, it is preferable to manufacture the composite superconductor using an unpolished laminate consisting only of the unpolished metal layer and the superconductor layer, as described above, because the density of the superconductor layer (the proportion of superconducting material in the composite superconductor) can be increased in the resulting composite superconductor, thereby improving its properties. 【0019】 Commercially available unpolished laminates can also be used. Furthermore, the unpolished laminate can be wrapped around the core material, ensuring that at least a portion of the core material is covered before polishing. 【0020】 [Formation of Unit Layer Regions] The manufacturing method of the present invention includes polishing at least a portion of the surface of the unpolished metal layer of an unpolished laminate that is opposite to the superconductor layer, thereby forming a unit laminate region that includes a thin metal layer containing the polished metal layer and a superconductor layer formed on the thin metal layer. 【0021】 (Unit layer region) The unit stacking region is the polished portion of the unpolished laminate and includes a thin metal layer containing a polished metal layer and a superconductor layer formed on the thin metal layer. The thin metal layer is the polished portion of the unpolished metal layer and is thinner than the unpolished metal layer. Preferably, the thin metal layer has substantially the same composition as the polished metal layer (i.e., substantially the same composition as the unpolished metal layer except for thickness and surface roughness Ra), but it may contain impurities that are inevitably introduced or generated during polishing. Since polishing forms a thin metal layer that is thinner than the unpolished metal layer, the unit stacking region is thinner than the unpolished laminate. By performing polishing, a laminate is obtained in which the unit stacking region includes a metal layer (a layer after polishing at least a part of the unpolished metal layer) and a superconductor layer formed on the metal layer, and its thickness is thinner than the thickness of the unpolished laminate before polishing. The unit stacking region has substantially the same composition as the unpolished laminate, except that the unpolished metal layer is a thin metal layer. As described above, the unpolished laminate may include layers other than the unpolished metal layer and the superconductor layer (for example, adhesion-enhancing layers or strength-enhancing layers), and the unit laminate region may also include layers other than the thin metal layer and the superconductor layer. 【0022】 Polishing can be performed uniformly, or the amount of polishing can be varied depending on the area being polished, such as gradually thinning the metal layer after polishing. The polishing method is not particularly limited, and known dry polishing or wet polishing methods can be used, but dry polishing is preferred. 【0023】 Dry polishing is a method of processing by bringing the polishing tool into contact with the workpiece without using water or grinding fluid. When the polishing tool and the workpiece come into contact, the contact point becomes hot, so wet polishing, which uses water or grinding fluid to cool it, was thought to be more effective. However, it has been found that when using water or grinding fluid to polish the unpolished metal layer of an unpolished laminate, these liquids may react with the superconductor or unpolished metal layer, or damage may occur, resulting in deterioration of the properties. Therefore, in the manufacturing method of the present invention, it is preferable to polish the unpolished metal layer by dry polishing. The method of dry polishing is not particularly limited and known methods can be used, including methods that use rotation, vibration, or airflow to bring the abrasive material into contact with the unpolished metal layer, or methods that use abrasive paper to polish the unpolished metal layer. 【0024】 Depending on the thickness of the superconductor layer, polishing is preferably performed so that the thickness of the metal thin layer (the polished portion of the unpolished metal layer) in the unit stacking region is 0.05 μm or more and less than 200 μm, more preferably 0.1 to 100 μm, and even more preferably 0.3 to 30 μm. By polishing the unpolished metal layer to such a thickness, the proportion of superconductors in the unit stacking region can be increased without worsening handling properties. Furthermore, the unit stacking region may or may not have a uniform thickness, but it is preferable that it is within the above numerical range. 【0025】 Polishing involves reducing the thickness of the superconductor layer in the unit stack region (the polished portion of the unpolished stack) to t s The thickness of the metal thin layer (the polished part of the unpolished metal layer) is t m In this case, 0.1 × t s ≤t m ≤3 × t s It is preferable to perform the procedure in such a way that the result is 0.1 × t s ≤t m ≤ × t s It is more preferable to do so. Thickness t of the metal thin layer m However, the thickness t of the superconducting layer s If it is less than 0.1 times, it may be difficult to handle. Also, the thickness t of the thin metal layerm However, the thickness t of the superconducting layer s If the ratio becomes greater than three times this value, it is undesirable because the proportion of superconductors in the unit stack region decreases. 【0026】 Furthermore, polishing is preferably performed so that the average roughness Ra of the polished surface (the surface opposite to the superconductor layer) of the metal thin layer (the polished portion of the unpolished metal layer) is 0.1 μm or less. The average roughness Ra of the polished surface is preferably adjusted appropriately according to the thickness of the unpolished metal layer. For example, if the thickness of the unpolished metal layer is 1 μm or more and 200 μm or less, it is preferable to polish the surface so that the average roughness Ra of the polished surface is 0.1 μm or less. Polishing to such an average roughness Ra is preferable because it makes it less likely to damage the superconductor layer when stacking unit stacking regions and improves adhesion with adjacent layers. 【0027】 [Formation of a multi-layered structure] The manufacturing method of the present invention preferably further includes forming a multi-layer structure in which two or more unit layered regions are stacked so that metal thin layers and superconducting layers are alternately arranged. The two or more unit layered regions forming the multi-layer structure may have the same configuration or may have different configurations. The multi-layer structure is a structure in which two or more metal thin layers and superconducting layers are stacked alternately. For example, the multi-layer structure can be formed by stacking two or more unit layered regions, or it may be a structure in which two or more unit layered regions are stacked via another layer. The multi-layer structure can be formed, for example, by stacking or winding multiple laminates having unit layered regions obtained by polishing an unpolished structure, or by polishing an unpolished laminate using a core material or the like so that unit layered regions are formed on top of each other. 【0028】 Furthermore, by using a core material, when polishing the unpolished laminate, the core material functions as a support member for mechanical strength, allowing the unpolished laminate to be processed to an extremely thin degree. In other words, when polishing an unpolished laminate without a core material, there is a possibility that the unpolished laminate will break or wrinkle, rendering it unusable, making it difficult to polish the unpolished metal layer to a very thin degree. Also, attempting to polish the unpolished metal layer to a thin degree requires extremely careful work, making it difficult to improve productivity. On the other hand, when polishing an unpolished laminate using a core material, the core material can increase the mechanical strength of the unpolished laminate, allowing the metal layer to be processed to an extremely thin degree, and the unpolished laminate will not break during processing, improving workability and increasing productivity. 【0029】 (Embodiment 1) The manufacturing method 1 of the present invention may include a polishing step A in which at least a portion of the surface of the unpolished metal layer of an unpolished laminate that is opposite to the superconductor layer is polished to obtain a laminate having unit stacking regions, and a stacking step in which the laminates obtained in polishing step A are stacked so that metal thin layers and superconductor layers are alternated to form a multi-layer structure. 【0030】 The laminate obtained in polishing step A is obtained by polishing at least a portion of the unpolished metal layer of the unpolished laminate, and has a unit laminate region. That is, the laminate has a portion of the polished and formed metal thin layer (thickness t m The laminate includes a metal layer having a portion that is t, and a superconducting layer formed on this metal layer. The configuration of the laminate is substantially the same as that of the unpolished laminate except for the thickness and surface roughness Ra of the metal layer, and the superconducting layer of the laminate is substantially the same as that of the unpolished laminate. The metal layer of the laminate consists of a portion of a thin metal layer, or a portion of a thin metal layer (with a thickness of t m It consists of a polished portion and an unpolished portion. 【0031】 In polishing step A, the thickness of the superconductor layer is t s , the thickness of the thin metal layer m In this case, 0.1 × t s ≤tm ≤3 × t s It is preferable to obtain a laminate having a unit stack region in which the average roughness Ra of the surface opposite to the metal thin layer superconductor is 0.1 μm or less. s ≤t m ≤t s It is more preferable to obtain a laminate having a unit stack region in which the average roughness Ra of the surface opposite to the metal thin-layer superconductor is 0.1 μm or less. That is, the thickness of the superconductor layer of the laminate is t s The thickness of the metal layer of the laminate is t M Therefore, 0.1 × t s ≤t M ≤3 × t s It is preferable to obtain a laminate having a unit stacking region, wherein the average roughness Ra of the metal layer in the unit stacking region on the side opposite to the superconductor layer is 0.1 μm or less, and 0.1 × t s ≤t M ≤t s It is more preferable to obtain a laminate having a unit stacking region, wherein the average roughness Ra of the metal layer in the unit stacking region on the side opposite to the superconductor layer is 0.1 μm or less. 【0032】 The lamination process involves stacking the laminates obtained in polishing process A so that thin metal layers and superconducting layers are stacked alternately, thereby forming a multi-layer structure. A multi-layer structure can be formed by stacking the laminates so that the unit stacking regions of the laminates overlap. The unit stacking regions may also be stacked with other layers in between. The method of stacking the laminates is not particularly limited, and methods such as bonding the laminates together with an adhesive, fixing the laminates with tape after stacking, or curing and fixing the laminates with a curing resin after stacking can be used. 【0033】 In the lamination process, the number of layers in a unit lamination region is two or more. The number of layers is not particularly limited and is appropriately selected according to the specifications of the composite superconductor and the equipment / system on which it is installed. A realistic number of layers is several tens to several thousand. Specifically, 10 to 9000 layers are preferred, and 100 to 600 layers are more preferred. By using a multi-layer structure, the superconducting properties can be further improved. 【0034】 A manufacturing method comprising a polishing step A and a lamination step can be used to obtain, for example, a composite superconductor having a portion of a multi-layer structure formed by stacking two or more unit lamination regions, which include two or more laminates having unit lamination regions. 【0035】 Furthermore, a step of processing the laminate into a desired shape may be included between the polishing step A and the lamination step, and a step of processing the multi-layered laminate, including a multi-layered structure, into a desired shape may be included after the lamination step. Because the laminate is thin, it has excellent bendability and processability, is easy to cut, and is easy to shape into a desired form. The laminate obtained in polishing step A, and the multi-layered laminate having a portion of the unit lamination region of said laminate that is a multi-layered structure, can be easily processed into a desired shape by cutting or punching. Alternatively, a core material of a desired shape may be covered with a multi-layered laminate including a multi-layered structure obtained in the lamination step to obtain a composite superconductor of a desired shape. 【0036】 (Embodiment 2) The manufacturing method, which includes polishing step A and lamination step, will be explained in more detail below based on Figure 1. Note that each schematic diagram in Figure 1 is a view from the front. 【0037】 The manufacturing method 2 of the present invention shown in Figure 1 comprises a polishing step A for obtaining a laminate 20, and a lamination step for stacking the laminate 20 obtained in polishing step A to form a multi-layer structure. This makes it possible to obtain a composite superconductor 200 which is a multi-layer structure consisting of a portion of the laminate 20 in which two or more unit lamination regions 20R are stacked. 【0038】 In the manufacturing method 2 of the present invention shown in Figure 1, an unpolished laminate 10 (Figure 1(A)) is used, which includes an unpolished metal layer 12 and a superconductor layer 14 formed on the unpolished metal layer 12. In polishing step A, as shown in Figure 1(B), the surface 12S of the unpolished metal layer 12 of the unpolished laminate 10 opposite to the superconductor layer 14 is dry polished with a polishing tool 1, thereby forming a thin metal layer 22 that is thinner than the unpolished metal layer 12, and this polished portion becomes a unit laminate region 20R. Thickness t of the unit laminate region 20R 20The thickness T of the unpolished laminate 10 10 To make it thinner, the thickness of the superconducting layer 14 in the unit stacking region 20R is reduced to t s The thickness of the metal thin layer 22 is t m Therefore, t s =t m As a result, the proportion of the superconducting layer 14 is higher compared to the unpolished portion. The polished laminate 20 consists of a unit laminate region 20R including a metal thin layer 22 and a superconducting layer 14 formed on the metal thin layer 22, as shown in Figure 1(C). 【0039】 Although the entire laminate 20 is a unit laminate region 20R, the manufacturing method 2 of the present invention may also involve dry polishing only a portion of the unpolished metal layer 12 of the unpolished laminate 10. 【0040】 Next, a lamination process is performed. In the lamination process, as shown in Figure 1(D), multiple laminates 20 (unit lamination regions 20R) obtained in polishing process A in Figures 1(A) to (C) are stacked so that the metal thin layers 22 and superconductor layers 14 alternate. This allows a composite superconductor 200 to be obtained. In the composite superconductor 200, the number of stacks of the laminate 20 is 2500 to 7500 layers, and the thickness of the composite superconductor 200 is 0.5 cm to 1.5 cm. If a part of the laminate 20 has unit lamination regions 20R, a composite superconductor can be obtained by stacking the laminates 20 so that the unit lamination regions 20R overlap. 【0041】 Furthermore, a composite superconductor 200 that is a multi-layered structure can be obtained by cutting or punching out the laminated structure 20 into a desired shape and then stacking them, or by cutting or punching out the multi-layered composite superconductor 200 into a desired shape. 【0042】 (Embodiment 3) The manufacturing method 3 of the present invention can be a manufacturing method comprising a coating step of covering at least a portion of the core material with an unpolished laminate with an unpolished metal layer on the outside, and a polishing step B of polishing at least a portion of the unpolished laminate covering the core material. 【0043】 This makes it possible to obtain a composite superconductor comprising a core material and a laminate, wherein the laminate comprises a metal layer and a superconducting layer formed on the metal layer, and has a unit laminate region, and at least a portion of the surface of the core material is covered by the unit laminate region. By using the core material, multi-layer structures can also be formed more easily, as will be described later. Furthermore, by selecting the shape of the core, composite superconductors of various shapes can be obtained. 【0044】 The core material is the central component of the composite superconductor and can be a molded body of a ferromagnetic material (iron, cobalt, nickel, alloys thereof, etc.), a molded body of a diamagnetic material (copper, etc.), a magnet, or a composite structure thereof. The shape of the core material is not particularly limited and can be appropriately selected according to the purpose, and can be rectangular, cubic, cylindrical, polyhedral, or an irregular shape with curved or uneven surfaces. 【0045】 The core material is preferably shaped with two opposing surfaces, more preferably thin and flat (flat) in shape with two opposing surfaces having the maximum surface area, and the thickness of the core material is preferably about 0.2 to 1.5 mm. Furthermore, it is preferable that at least two opposing surfaces having the maximum surface area of ​​the core material are covered with a uniformly thin laminate or a thin portion of the laminate. It is preferable that at least two opposing surfaces having the maximum surface area of ​​the core material are covered with a unit laminate region of the laminate, and more preferably that they are covered with a multi-layer structure in which two or more unit laminate regions are stacked. 【0046】 Furthermore, the core material may have two opposing surfaces with the largest surface area positioned approximately parallel to each other, or they may be positioned non-parallel to each other. For example, when forming a multi-layered structure using the core material and then extracting the core material to manufacture a composite superconductor without the core material (for example, a flat structure made of rolled-up layers), using a core material where the two opposing surfaces with the largest surface area are positioned non-parallel to each other makes it easier to extract the core material. 【0047】 Polishing process B is the same as polishing process A, except that the unpolished laminate covers the core material. 【0048】 Furthermore, in the manufacturing method 3 of the present invention, it is preferable to form a multi-layered structure by repeating the coating step and polishing step B. In this case, at least a portion of the core material may be coated with a new unpolished laminate each time the coating step is performed, or polishing step B may be performed on the portion of the unpolished laminate that covers the core material while at least a portion of the core material is covered with an unpolished laminate. 【0049】 (Embodiment 4) The manufacturing method 4 of the present invention may include a winding step of winding a long unpolished laminate around a core material so that the unpolished metal layer faces outwards, and a polishing step B of polishing the unpolished laminate wound around the core material. This method is also an example of the manufacturing method of the present invention having a coating step and a polishing step B. 【0050】 Furthermore, in the manufacturing method 4 of the present invention, it is preferable to form a multi-layer structure by repeating the winding step and the polishing step B. The repetition of the winding step and the polishing step B may be performed by winding a new unpolished laminate onto the core material each time the winding step is performed and then performing the polishing step B, or by winding a portion of the unpolished laminate onto the core material while polishing the unpolished laminate wound onto the core material and repeating the winding step and the polishing step B. There is no particular limit to the number of repetitions of the winding step and the polishing step B as long as it is two or more times, but for example it can be five or more times, ten or more times, fifty or more times, 100 or more times, etc. The upper limit can be 9000 times or less, 4500 times or less, 1200 times or less, 600 times or less, 300 times or less, etc. 【0051】 The manufacturing method, which includes a winding process and a polishing process B, will be described in more detail below based on Figures 2 to 5. Each schematic diagram in Figures 2 to 5 is a view from the front. Elements common to Figure 1 and Figures 2 to 5 are denoted by the same reference numerals, and explanations may be omitted. 【0052】 (Embodiment 5) The manufacturing method 5 of the present invention shown in Figure 2 includes a winding step of winding an unpolished laminate 11 around a core material 16, and a polishing step B of polishing at least a portion of the outer surface of the unpolished laminate 11 wound around the core material 16. This method is also an example of the manufacturing method of the present invention having a coating step and a polishing step B. By doing so, a composite superconductor 300 including a laminate 30 and a core material 16 around which the laminate 30 is wound can be obtained. 【0053】 In the manufacturing method 5 of the present invention shown in Figure 2, an unpolished laminate 11 and a core material 16 are used, as shown in Figure 2(A). The unpolished laminate 11 is a long laminate including an unpolished metal layer 12 and a superconducting layer 14 formed on the unpolished metal layer 12. The core material 16 is a rectangular parallelepiped with a thickness of 0.2 to 1.5 mm, a length of 5 to 20 mm, and a width of 5 to 20 mm, with two opposing surfaces having the largest surface area designated as the upper surface 16a and the lower surface 16b. 【0054】 In the winding process shown in Figure 2(B), the unpolished laminate 11 is wound around the core material 16 with the unpolished metal layer 12 facing outwards, covering the bottom surface 16b, right side surface 16c, and top surface 16a of the core material 16. The starting end 11s and ending end 11e of the unpolished laminate 11 are then bonded and fixed to the left side surface 16d of the core material 16 with an adhesive (not shown). 【0055】 As the adhesive, moisture-curing adhesives such as cyanoacrylate adhesives, or UV-curing adhesives such as acrylic adhesives or epoxy adhesives can be used. In this case, the unpolished laminate 11 is bonded to the core material 16 at its starting end 11s and ending end 11e with adhesive, but the entire unpolished laminate 11 may also be bonded to the core material 16 with adhesive. From the viewpoint of reducing the influence of the adhesive, it is preferable to bond the starting end 11s and ending end 11e of the unpolished laminate 11 to the core material 16. 【0056】 Next, in polishing step B, as shown in Figure 2(C), the surface 12S of the unpolished metal layer 12 covering the upper surface 16a of the core material 16 of the unpolished laminate 11, opposite to the superconductor layer 14, is dry polished using the polishing tool 1. Similarly, the surface 12S of the unpolished metal layer 12 covering the lower surface 16b of the core material 16 of the unpolished laminate 11, opposite to the superconductor layer 14, is dry polished. Dry polishing may be performed by polishing the unpolished metal layer 12 covering the upper surface 16a and the lower surface 16b separately, or by polishing the upper surface 16a and the lower surface 16b simultaneously. By dry polishing the unpolished metal layer 12 covering the upper surface 16a and the lower surface 16b of the core material 16, a unit laminate region 30R is formed in the portions covering the upper surface 16a and the lower surface 16b. 【0057】 As a result, a composite superconductor 300 is obtained, which includes a core material 16 and a laminate 30 wrapped around the core material 16, as shown in Figure 2(D). The laminate 30 includes a metal layer 32 consisting of a metal thin layer 32a portion and an unpolished portion 32b, and a superconductor layer 14 laminated on the metal layer 32, with the metal layer 32 facing outwards, covering the top surface 16a, right side surface 16c, and bottom surface 16b of the core material 16. Furthermore, the portion of the laminate 30 covering the top surface 16a and bottom surface 16b of the core material 16 is a unit laminate region 30R formed by polishing, and the thickness t of the portion of the laminate 30 covering the top surface 16a of the core material 16 a and the thickness t covering the lower surface 16b of the core material 16 b This refers to the thickness T of the portion covering the right side surface 16c of the core material 16 of the laminate 30. c It is thinner than t. In the laminate 30, the thickness of the superconductor layer 14 in the unit laminate region 30R is t s The thickness of the metal layer 32 (thin metal layer) is t m Therefore, t s =t m Therefore, the proportion of the superconducting layer 14 is higher compared to the unpolished portion. 【0058】 Furthermore, a multi-layered structure can be formed by repeating the winding process and polishing process B. Figure 3 shows the result of winding a new unpolished laminate onto the core material each time the winding process is performed, followed by polishing process B. Similar to the winding processes in Figures 2(A) and (B) and polishing process B in Figures 2(C) and (D), by repeating the winding and polishing of the unpolished laminate 11, a composite superconductor 301 is obtained in which the core material 16 is covered with two or more laminated layers 30, as shown in Figure 3. In each laminate 30, the thickness of the metal layer 32 covering the upper surface 16a and lower surface 16b of the core material 16 is thinner than the thickness of the metal layer 32 covering the right side surface 16c and left side surface 16d of the core material 16. That is, the composite superconductor 301 has a multi-layered structure 30RM formed on the upper surface 16a and lower surface 16b of the core material 16, where unit laminated regions 30R are laminated. 【0059】 (Embodiment 6) The manufacturing method 6 of the present invention, shown in Figures 4 and 5, involves wrapping a portion of the unpolished laminate 11 around a core material 16 so that the unpolished metal layer 12 faces outward, while polishing at least a portion of the outer surface of the unpolished laminate 11 wrapped around the core material 16. This method is also an example of the manufacturing method of the present invention, which includes a coating step and a polishing step B. By using such a manufacturing method, a multi-layer structure can be easily formed. Furthermore, when forming a multi-layer structure, even without providing an adhesive layer between the laminates, the starting end of the unpolished laminate 11 can be bonded to the core material 16, followed by wrapping and polishing, and finally the ending end of the unpolished laminate 11 can be bonded to the core material 16, thereby forming a multi-layer structure. For this reason, a structure without an adhesive layer between the laminates can also be created. 【0060】 In the manufacturing method 6 of the present invention shown in Figures 4 and 5, first, as shown in Figure 4(A), the starting end 11s of the unpolished laminate 11 is bonded to the left side surface 16d of the core material 16 with the unpolished metal layer 12 facing outwards, and the first winding is wrapped so as to cover the bottom surface 16b (the surface with the largest area), the right side surface 16c, and the top surface 16a (the surface with the largest area) of the core material 16. 【0061】 Next, as shown in Figure 4(B), the unpolished metal layer 12 covering the upper surface 16a and lower surface 16b of the core material 16 is dry polished. Dry polishing may be performed by polishing the portions covering the upper surface 16a and lower surface 16b separately, or by polishing the upper surface 16a and lower surface 16b simultaneously. This forms a unit laminated region 40R in the portions covering the upper surface 16a and lower surface 16b of the core material 16. 【0062】 Next, as shown in Figure 4(C), after winding the second turn of the unpolished laminate 11, the unpolished metal layer 12 covering the upper surface 16a and lower surface 16b of the core material 16 is dry polished, as shown in Figure 4(D). This polishes the unpolished metal layer 12 covering the upper surface 16a and lower surface 16b of the core material 16 of the second turn of the unpolished laminate 11, and forms a unit laminate region 40R. 【0063】 The process involves repeatedly wrapping the unpolished laminate 11 around the core material 16 and polishing the unpolished metal layer 12 of the unpolished laminate 11 wrapped around the core material 16. The number of times the unpolished laminate 11 is wrapped around the core material 16 is two or more, and can be, for example, 1300 to 3800 times. Finally, the end of the unpolished laminate 11 is bonded and fixed with adhesive. 【0064】 Figure 4 shows a process where the unpolished laminate 11 is wrapped around the core material 16 once and then polished. Alternatively, the unpolished laminate 11 may be wrapped around the core material 16 half a turn at a time, and the unpolished laminate 11 wrapped around the core material 16 may then be polished. 【0065】 As a result, as shown in Figure 5, a composite superconductor 400 is obtained, which includes a core material 16 and a laminate 40 wrapped around the core material 16 two or more times. The laminate 40 includes a metal layer 42 consisting of a thin metal layer 42a portion and an unpolished portion 42b portion, and a superconducting layer 14 laminated on the metal layer 42, and has a unit laminated region 40R. The laminate 40 is wrapped around the core material 16 multiple times with the metal layer 42 on the outside. The portion of the laminate 40 covering the upper surface 16a and lower surface 16b of the core material 16 has a multi-layered structure 40RM in which unit laminated regions 40R formed by polishing are laminated, and the thickness of the metal layer 42 of the laminate 40 covering the upper surface 16a and lower surface 16b of the core material 16 is thinner than the thickness of the portion covering the right side 16c and left side 16d of the core material 16. In the laminate 40, the thickness of the superconducting layer 14 in the unit laminated region 40R is t s The thickness of the metal layer 42 in the unit stacking region 40R is t m Therefore, t s =t m Therefore, the proportion of the superconducting layer 14 is higher compared to the unpolished portion. 【0066】 In Figures 2 to 5, only the portions covering the upper surface 16a and lower surface 16b of the core material 16 of the unpolished laminate 11 are polished. However, the portions covering the right side 16c and left side 16d of the core material 16 may also be polished. Furthermore, in Figures 2 to 5, the amount of polishing of the unpolished metal layer 12 covering the upper surface 16a and lower surface 16b of the core material 16 is the same, and the thickness of the portion covering the upper surface 16a and the thickness covering the lower surface 16b of the core material 16 of the laminates 30 and 40 is the same, but the amount of polishing of the unpolished metal layer 12 covering the upper surface 16a and lower surface 16b of the core material 16 may be different. 【0067】 Furthermore, in Figures 2 to 5, the composite superconductor is constructed while leaving the core material 16 in place. However, for example, in Figure 3, the unpolished laminate 11 can be fixed by bonding its starting and ending ends together, and after repeatedly performing the winding and polishing processes B in the same manner as in Figure 2, the core material 16 can be slowly pulled out to create a form without the core material 16 (for example, a composite superconductor including a flattened wound laminate). In this case, the degree of degradation of properties can be reduced by reducing the number of components that are not involved in superconductivity. Moreover, although a cavity is created after the core material 16 is removed, the composite superconductor can be crushed by applying pressure to the main surface of the composite superconductor (as the cavity exists, the cavity decreases and the thickness of the composite superconductor becomes thinner), thereby improving the proportion of the superconductor layer in the composite superconductor (increasing the amount of superconductor layer per unit thickness). 【0068】 Furthermore, while the core materials in Figures 2 to 5 have two opposing surfaces with the largest surface area positioned approximately parallel to each other, it is also possible to create a configuration that facilitates the extraction of the core material 16 by using a core material 16 in which the two opposing surfaces with the largest surface area are not parallel to each other (for example, a core material 16 in which the cross-sectional area of ​​the back surface (opposite to the side shown in the illustration) is smaller than the cross-sectional area of ​​the front surface (side shown in the illustration) of the core material 16 in Figure 3). Alternatively, the shape of the core material 16 can be made uniform, and when the core material 16 is extracted, it can be cooled with liquid nitrogen or the like to shrink the core material 16, making it easier to extract the core material 16 from the wound laminate 30 or laminate 40. 【0069】 Furthermore, in Figures 2 to 5, the metal layers 32 formed on the upper surface 16a and lower surface 16b of the core material 16 were polished to approximately the same thickness (the thickness of the metal thin layers was made approximately the same), but the amount of polishing can be appropriately set depending on the usage environment of the composite superconductor. 【0070】 For example, in Figure 3, the thickness of the metal layer 32 can be made thinner as you move away from the upper surface 16a and lower surface 16b of the core material 16 (towards the surface), thereby increasing the stacking density of the superconducting layer 14 on the surface of the multi-layered structure 30RM of the composite superconductor 301 compared to other parts. Alternatively, the thickness of the metal layer 32 can be made thicker as you move away from the upper surface 16a and lower surface 16b of the core material 16, thereby lowering the stacking density of the superconducting layer 14 on the surface of the multi-layered structure 30RM of the composite superconductor 301 compared to other parts. Furthermore, the thickness of the metal layer 32 can be made periodically or in different parts to adjust the superconducting properties. By varying the thickness of the metal layer 32, the stacking density of the superconducting layer 14 near the surface of the multi-layered structure 30RM of the composite superconductor 301 can be increased, thereby adjusting the magnetic flux density and the levitation height of magnets and the like. Conversely, by lowering the stacking density of the superconductor layer 14 near the surface of the multi-layer structure 30RM of the composite superconductor 301 (i.e., reducing the amount of polishing of the unpolished metal layer on the surface and increasing the thickness of the metal layer), it is possible to increase the mechanical strength of the composite superconductor 301 and improve its shape retention. 【0071】 (Embodiment 7) Furthermore, in another embodiment, multiple composite superconductors (finished product A) with 500 layers each (including at least a portion where one metal layer and one superconductor layer are stacked) can be prepared. If a 1000-layer composite superconductor is desired, two finished products A can be stacked and joined together with an adhesive. Similarly, a composite superconductor (finished product B) with 200 layers each (including at least a portion where one metal layer and one superconductor layer are stacked) and a composite superconductor (finished product C) with 300 layers each (including at least a portion where one metal layer and one superconductor layer are stacked) can be prepared. If a 5400-layer composite superconductor is desired, this can be achieved by preparing 10 finished products A and 2 finished products B and stacking them. If a 5300-layer composite superconductor is desired, this can be achieved by stacking 10 finished products A and 1 finished product C. This method allows for easy adjustment of the number of layers, improving the design flexibility. 【0072】 (Embodiment 8) In another embodiment, a multi-layer structure may be formed by polishing an unpolished laminate to obtain a laminate, which then covers at least a portion of the core material. For example, a manufacturing method can be used in which a unit laminate region formed by polishing at least a portion of the surface of the unpolished metal layer of the unpolished laminate opposite to the superconductor layer is wrapped around the core material to form a multi-layer structure. 【0073】 Figure 6 shows examples of composite superconductors manufactured using the manufacturing method of the present invention. Figure 6(A) can be used, for example, in bearings (such as bearings) for drive devices, motors, pumps, etc., used in the cryogenic region. Figure 6(B) can be used, for example, as a superconducting member used in linear motors that perform linear motion. Figure 6(C) can be used, for example, as a superconducting member in processing machines (polishing machines, grinding machines, etc.) to levitate magnets and process objects using magnets. Furthermore, since the composite superconductor of the present invention can be processed into various shapes, it can be used, for example, in medical devices (such as MRI and other diagnostic equipment) and in magnetic susceptibility measuring instruments. [Examples] 【0074】 The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples unless its essence is changed. 【0075】 [Example 1] As the unpolished laminate, a wire (1 cm wide, 3 cm long, 9 μm thick) with GBCO deposited on a nickel alloy base was used. The back surface of the wire (the side opposite the superconducting layer) was polished under the following polishing conditions to reduce the wire thickness to 5 μm. Five of these polished 5 μm thick wires and five unpolished 9 μm thick wires were stacked and bonded together with polyimide tape to form a composite superconductor (70 μm thick). 【0076】 (polishing conditions) • Polishing equipment: Maruto ML-160A • Rotation speed: 60 rpm • Abrasive material: silicon carbide • Sandpaper: 400 grit • Polishing time: 30 minutes 【0077】 [Comparative Example 1] Eight unpolished wires with a thickness of 9 μm were stacked and bonded together with polyimide tape to obtain a comparative superconductor (thickness 72 μm). 【0078】 [Magnet levitation experiment] A magnet levitation experiment was conducted using the superconductor from Example 1. First, the superconductor of Example 1 was sufficiently cooled to 77K with liquid nitrogen in a field pool. Then, a levitation experiment was conducted by slowly bringing a ring-shaped neodymium magnet with an outer diameter of 2.5 cm, an inner diameter of 2.0 cm, and a thickness of 0.5 cm closer to the cooled superconductor. As a result, the neodymium magnet levitated by an average of about 2-3 mm. The field pool was filled with liquid nitrogen to a thickness of at least 0.5 mm, ensuring that the superconductor was cooled reliably. 【0079】 Similarly, a magnet levitation experiment was conducted on the superconductor of Comparative Example 1, but the magnet did not levitate. 【0080】 Figure 7 shows the levitation experiment of a magnet using the superconductor of Example 1. Figure 8 shows the levitation experiment of a magnet using the superconductor of Comparative Example 1. As shown in Figures 7 and 8, although the superconductors of Example 1 and Comparative Example 1 were almost the same thickness, the magnet levitated when using the superconductor of Example 1, but did not levitate when using the superconductor of Comparative Example 1. [Industrial applicability] 【0081】 This invention is industrially useful because it can be used in various fields that utilize superconductivity. [Explanation of symbols] 【0082】 1 Polishing tools 10, 11 Unpolished laminate 11s Start part 11e Termination section 12 Unpolished metal layer 12S side 14 Superconducting Layer 16 Core material 16a Top side 16b Bottom side 16c Right side 16d left side 20, 30, 40 laminated layers 20R, 30R, 40R Unit Layer Region 30RM, 40RM multi-layer structure 22, 32, 42 metal layer 32a, 42a thin metal layer 32b, 42b Unpolished portion of the metal layer 200, 300, 301, 400 composite superconductors

Claims

[Claim 1] A method for manufacturing a composite superconductor having a portion in which a thin metal layer and a superconducting layer are laminated, wherein the thin metal layer and the superconducting layer each consist of two or more layers, The method includes polishing at least a portion of the surface of the unpolished metal layer opposite to the superconductor layer of an unpolished laminate comprising an unpolished metal layer and a superconductor layer formed on the unpolished metal layer, thereby forming a unit laminate region comprising a thin metal layer containing the polished metal layer and the superconductor layer formed on the thin metal layer. A winding step in which the unpolished laminate is wrapped around the core material so that the unpolished metal layer is on the outside, A method for manufacturing a composite superconductor, comprising a polishing step B of polishing at least a portion of the outer surface of the unpolished laminate wrapped around the core material. [Claim 2] The method for manufacturing a composite superconductor according to claim 1, wherein the polishing is dry polishing. [Claim 3] Furthermore, the method for manufacturing a composite superconductor according to claim 1 or 2, comprising forming a multi-layer structure in which two or more unit stacking regions are stacked so that the metal thin layer and the superconductor layer are alternately arranged. [Claim 4] A method for manufacturing a composite superconductor according to any one of claims 1 to 3, comprising repeating the winding step and the polishing step B to form a multi-layered structure. [Claim 5] A method for manufacturing a composite superconductor according to claim 4, wherein a portion of the unpolished laminate is wrapped around the core material such that the unpolished metal layer faces outward, and at least a portion of the outer surface of the unpolished laminate wrapped around the core material is polished. [Claim 6] The thickness of the superconductor layer in the unit stacking region is t s , the thickness of the metal thin layer is t m In this case, 0.1 × t s ≤ t m ≤ 3 × t s A method for manufacturing a composite superconductor according to any one of claims 1 to 5, wherein polishing is performed so that the result is as follows. [Claim 7] A method for manufacturing a composite superconductor according to any one of claims 1 to 6, wherein polishing is performed so that the average surface roughness Ra after polishing is 0.1 μm or less.

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