JP5432863B2 - Alignment substrate for film formation and superconducting wire - Google Patents

Description

The present invention relates to a film forming oriented substrate and a superconducting wire, and more particularly, to a related to the alignment substrate film, and the film forming oriented substrate superconducting wire superconducting film is formed on the material.

  Since the discovery of high-temperature superconductors, high-temperature superconducting wires have been actively developed for applications in power devices such as cables, current limiters, and magnets. Here, in order to obtain an excellent high-temperature superconducting wire, it is necessary to form a superconducting film with high orientation.

  In order to improve the orientation of the superconducting film, it is necessary to orient the substrate on which the superconducting film is formed. There has been proposed a method in which a superconducting film or an intermediate layer and a superconducting film are sequentially formed on an oriented metal substrate having biaxial orientation as the orientation substrate for forming the superconducting film (for example, Non-Patent Documents 1 to 4). 4).

  Here, an intermediate layer having the same biaxial orientation as the oriented metal substrate is formed by epitaxially growing an intermediate layer on the oriented metal substrate using an oriented metal substrate in which metal atoms constituting the substrate are biaxially oriented as the metal substrate. A layer is formed, and a superconducting film having the same biaxial orientation as that of the intermediate layer is formed by epitaxially growing a superconducting film on the intermediate layer. Such a production method facilitates the production of a high-temperature superconducting wire having a superconducting film having a biaxial orientation suitable for superconductivity.

E. D. Specht et al., "Cube-textured nickel substrates for high-temperature superconductors", Supercond. Sci. Technol. 11 (1998), pp.945-949 J. H. Je et al., "Microstructure of RE2O3layers on cube textured Ni substrates", Physica C, (2003), 384, pp.54-60 BW Kang et al., "Comparative study of thickness dependence of critical current density of YBa2Cu3O7-δ on (100) SrTiO3 and on rolling-assisted biaxially textured substrates", J. Mater. Res., Jul. 2002, Vol.17, No.7, pp.1750-1757 D. Eyidi et al., "Growth of CeO2 thin films deposited on biaxially textured nickel substrates", J. Mater. Res., Jan. 2003, Vol.18, No.1, pp.14-26

  As the above-described biaxially oriented metal substrate, Ni (nickel) or Ni alloy in which several percent of a different metal (for example, W (tungsten)) is added to Ni is the mainstream. However, the material strength of Ni is low and the yield stress is only 30 MPa. Further, the strength can be improved by adding about 5% by mass of W to Ni. However, even in such a Ni alloy, the yield stress remains as low as 195 MPa.

  Since such Ni and Ni alloy have low strength, handling as a wire rod is bad, and when processing into a cable or the like, there is a problem that it is difficult to process with a stranded wire machine or the like.

The present invention has been made to solve the above problems, and an object thereof is to provide a film forming oriented substrate and a superconducting wire having high strength while maintaining excellent orientation.

The oriented substrate for film formation of the present invention comprises a first metal layer made of non-oriented and non-magnetic stainless steel, and a second metal layer bonded to the first metal layer and having a texture in which at least the surface layer is oriented. And a metal layer, wherein the first metal layer has higher strength than the second metal layer. The second metal layer includes a surface-side second metal layer bonded to the surface of the first metal layer and a back-side second metal layer bonded to the back surface of the first metal layer. The second metal layer on the front side and the second metal layer on the back side are separated from each other. Each of the second metal layer on the front surface side and the second metal layer on the rear surface side has a first layer and a second layer laminated on each other, and the first layer is more than the second layer. Is located on the first metal layer side, and the second layer is located on the surface layer side of the first layer. Each first layer of the second metal layer on the front side and the back side is made of copper, and each second layer of the second metal layer on the front side and the back side is made of nickel or a nickel alloy. .

According to the alignment substrate for film formation of the present invention, since the first metal layer has higher strength than the second metal layer, the strength of the alignment substrate for film formation is higher than that of the second metal layer alone. Can also be improved. In addition, since the first metal layer and the second metal layer are bonded together, the alignment substrate for film formation can be formed so that the second metal layer has a texture that is oriented, and good orientation is achieved. Sex can be maintained. Thus, by bonding the first metal layer and the second metal layer together, it is possible to obtain high strength while maintaining good orientation.
Further, since the first layer is located on the first metal layer side with respect to the second layer, and the second layer is located on the surface layer side with respect to the first layer, the first layer Thus, the lattice matching between the first metal layer and the second layer can be relaxed, and the diffusion of elements between the first metal layer and the second layer can be suppressed. Further, the first layer serves to prevent the first metal layer from affecting the orientation of the second layer.
Moreover, since the material of the first metal layer is made of stainless steel, a commercially available high-strength material can be used as the first metal layer, and costs can be reduced.

In the above-mentioned alignment substrate for film formation, at least the surface layer of each of the second metal layers on the front side and the back side preferably has a cubic texture.

  Thereby, when an intermediate | middle layer and a superconducting film are formed on the 2nd metal layer, the orientation of the superconducting film can be made favorable.

The superconducting wire of the present invention is characterized in that an intermediate layer and a superconducting film are formed on each of the second metal layers on the front side and the back side of the above-mentioned film forming alignment substrate.

  According to the superconducting wire of the present invention, a superconducting film having a good orientation can be formed and a superconducting wire having a high orientation can be formed because the orientation substrate for film formation having a high strength while maintaining a good orientation is used. The strength of can be improved.

  Note that the first metal layer and the second metal layer are bonded together by a method such as rolling. Each of the first and second metal layers and the first and second layers may be made of a metal made of a single metal element, or made of an alloy made of a plurality of metal elements. Also good.

  As described above, according to the alignment substrate for film formation of the present invention, since the first metal layer has higher strength than the second metal layer, the strength of the alignment substrate for film formation is increased to the second level. This can be improved as compared with the case of a single metal layer. In addition, since the first metal layer and the second metal layer are bonded together, the alignment substrate for film formation can be formed so that the second metal layer has a texture that is oriented, and good orientation is achieved. Sex can be maintained. Thus, by bonding the first metal layer and the second metal layer together, it is possible to obtain high strength while maintaining good orientation.

  Further, according to the superconducting wire of the present invention, since a film-forming alignment substrate having high mechanical strength while maintaining good orientation can be used, a superconducting film having good orientation can be formed, and The strength of the superconducting wire can be improved.

It is a schematic sectional drawing which shows the structure of the orientation substrate for film formation in Embodiment 1 of this invention. It is a schematic sectional drawing which shows the structure of the superconducting wire using the oriented substrate for film formation in Embodiment 1 of this invention. It is a schematic sectional drawing which shows the structure of the orientation substrate for film formation in Embodiment 2 of this invention. It is a schematic sectional drawing which shows the structure of the superconducting wire using the oriented substrate for film formation in Embodiment 2 of this invention. It is a figure which shows the result of having measured the orientation of Ni orientation foil with the X-ray pole figure. It is a figure which shows the result of having measured the orientation of Cu orientation foil with the X-ray pole figure. It is a figure which shows the result of having measured the orientation of Ni film | membrane by the X-ray pole figure. It is sectional drawing which shows a mode that the 2nd metal layer demonstrated in Embodiment 1 was formed in both surfaces of the 1st metal layer. It is sectional drawing which shows a mode that the 2nd metal layer demonstrated in Embodiment 2 was formed in both surfaces of the 1st metal layer.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Embodiment 1)
FIG. 1 is a schematic cross-sectional view showing the configuration of the film-forming alignment substrate in Embodiment 1 of the present invention. Referring to FIG. 1, film forming alignment substrate 5A has a configuration in which a first metal layer 1 and a second metal layer 2 are bonded to each other. The bonding of the first metal layer 1 and the second metal layer 2 is performed by a method such as rolling.

  The first metal layer 1 is non-oriented and non-magnetic (that is, has no spontaneous magnetization). The second metal layer 2 is a single layer and has a texture in which at least the surface layer is oriented. The first metal layer 1 has higher strength than the second metal layer 2. Further, the strength of the first metal layer 1 is preferably such a strength that it does not stretch even when it is tensioned at a high temperature when the superconducting film is formed.

  In other words, when forming a superconducting film, the base material that forms the base of the superconducting film is formed into a tape shape, and the superconducting film is formed on the tape while feeding the tape in the longitudinal direction of the tape by the rotation of a pair of rolls. Is done. At this time, the tape is exposed to a high temperature and is given a tension when being fed by a roll. Since the first metal layer 1 has such a strength that it does not stretch even when it is tensioned at a high temperature during the formation of the superconducting film, the first metal layer 1 can be used as the base of the superconducting film. It can be used as a tape-shaped substrate.

  As the material having such strength, for example, stainless steel, nickel-based alloy or the like is used for the first metal layer 1. In the present embodiment, first metal layer 1 is made of, for example, stainless steel having a thickness T1 of 100 μm.

  The second metal layer 2 preferably has a very sharp and well-developed cubic texture (cube texture) by thermomechanical processing. The surface of the second metal layer 2 has a strong {100} <001> cubic orientation.

  Further, in this texture, the metal atoms constituting the second metal layer 2 are biaxially oriented. As the orientation direction in this biaxial orientation, the <100> axis is preferably oriented in the direction perpendicular to the substrate surface, and the <010> axis is oriented in the longitudinal direction of the second metal layer 2. The biaxial orientation includes not only perfect biaxial orientation but also crystal axis misalignment angle of 25 ° or less.

  The second metal layer 2 is not particularly limited as long as it has a biaxial orientation as described above, but Ni, Cu (copper), Ag (silver), W, V (vanadium), Cr ( It is preferably a metal made of a simple substance of chromium), Mo (molybdenum), Mn (manganese), Al (aluminum) and Fe (iron) or an alloy made of any combination of these metal elements. In the present embodiment, the second metal layer 2 is made of Ni having a thickness T2 of 30 μm, for example.

In addition, it is preferable that the 2nd metal layer 2 is not only a surface layer but the whole orientation.
According to the present embodiment, since the first metal layer 1 has higher strength than the second metal layer 2, the strength of the film-forming alignment substrate 5A is higher than that of the second metal layer 2 alone. Can also be improved. In addition, since the first metal layer 1 and the second metal layer 2 are bonded together, the film forming alignment substrate 5A can be formed so that the second metal layer 2 has an oriented texture. , Good orientation can be maintained. By bonding the first metal layer 1 and the second metal layer 2 in this way, it is possible to obtain a film-forming alignment substrate 5A having good orientation and high strength.

Next, a superconducting wire using the above-mentioned film forming alignment substrate 5A will be described.
FIG. 2 is a schematic cross-sectional view showing a configuration of a superconducting wire using the film-forming alignment substrate in Embodiment 1 of the present invention. Referring to FIG. 2, superconducting wire 10 </ b> A includes film forming alignment substrate 5 </ b> A shown in FIG. 1 described above, an intermediate layer, and superconducting film 3. An intermediate layer is formed on the film-forming alignment substrate 5A, and a superconducting film is formed on the intermediate layer. This superconducting film is, for example, a rare earth-based superconducting thin film, and is formed by vapor deposition or the like.

  In the present embodiment, since the second metal layer 2 has a good orientation, the orientation of the intermediate layer and the superconducting film 3 formed thereon can also be made good. In addition, since the first metal layer 1 has high strength, the strength of the superconducting wire 10A can be higher than that of a superconducting wire having pure Ni or Ni—W alloy as a substrate.

(Embodiment 2)
FIG. 3 is a schematic cross-sectional view showing the configuration of the film-forming alignment substrate in the second embodiment of the present invention. Referring to FIG. 3, the configuration of the film-forming alignment substrate 5 </ b> B of the present embodiment is different from the configuration of the first embodiment in that the first layer 2 a in which the second metal layers 2 are laminated with each other It differs in having the second layer 2b.

  The first layer 2a is bonded to the first metal layer 1 by, for example, rolling. The second layer 2b is formed on the first layer 2a by, for example, a plating method in order to coat the first layer 2a.

  The first layer 2a serves to relax the lattice matching between the first metal layer 1 and the second layer 2b, and an element is present between the first metal layer 1 and the second layer 2b. It also plays a role in suppressing diffusion. The first layer 2a also serves to prevent the first metal layer 1 from affecting the orientation of the second layer 2b.

  The material of the first layer 2a is preferably a metal made of Ni, Cu, Ag, W, V, Cr, Mo, Mn, Al and Fe or an alloy made of any combination of these metal elements. . In the present embodiment, the first layer 2a is made of Cu having a thickness T2a of 18 μm, for example.

  The material of the second layer 2b is preferably a metal made of Ni, Pd (palladium) and Ag alone or an alloy made of any combination of these metal elements. In the present embodiment, the second layer 2b is made of Ni having a thickness T2b of 1 μm, for example.

  Both the first layer 2a and the second layer 2b are preferably oriented, and the crystal axis shift between the crystal grains of the first layer 2a and the crystal grains of the second layer 2b It is preferably within 15 °. Here, the deviation of the crystal axis means the deviation of all the axes of the a-axis, the b-axis, and the c-axis. When the deviation of the crystal axis is within 15 °, the superconducting characteristics of the superconducting wire on the crystal axis are good.

  Since the other configuration of the film-forming alignment substrate 5B of the present embodiment is the same as that of the first embodiment shown in FIG. 1, the same components are denoted by the same reference numerals. The description is omitted.

  According to the present embodiment, the same effect as that of the first embodiment can be obtained. Furthermore, the first layer 2a can relax the lattice matching between the first metal layer 1 and the second layer 2b, and between the first metal layer 1 and the second layer 2b. It is also possible to suppress the diffusion of elements. The first layer 2a can also prevent the first metal layer 1 from affecting the orientation of the second layer 2b.

Next, a superconducting wire using the above-mentioned film forming alignment substrate 5B will be described.
FIG. 4 is a schematic cross-sectional view showing the configuration of a superconducting wire using the film-forming alignment substrate in the second embodiment of the present invention. Referring to FIG. 4, superconducting wire 10 </ b> B includes film forming alignment substrate 5 </ b> B shown in FIG. 3 described above, an intermediate layer, and superconducting film 3. An intermediate layer is formed on the film-forming alignment substrate 5B, and a superconducting film is formed on the intermediate layer. This superconducting film is, for example, a rare earth-based superconducting thin film, and is formed by vapor deposition or the like.

  In the present embodiment, since the second metal layer 2 having a laminated structure of the first layer 2a and the second layer 2b has a good orientation, an intermediate layer formed thereon and The orientation of the superconducting film 3 can also be made favorable. In addition, since the first metal layer 1 has high strength, the strength of the superconducting wire 10B can be higher than that of the superconducting wire using pure Ni or Ni—W alloy as a substrate.

  In the first and second embodiments, the case where the second metal layer 2 having a texture in which the surface layer is oriented is formed only on one side of the first metal layer 1 has been described. As shown in FIG. 9, the second metal layer 2 described in the first embodiment may be formed on both surfaces of the first metal layer 1, and the second metal layer 2 described in the second embodiment as shown in FIG. The metal layer 2 may be formed on both surfaces of the first metal layer 1.

Hereinafter, Example 1 will be described with reference to the drawings.
Referring to FIG. 1, SUS316L (JIS (Japanese industrial standard) standard stainless steel) is used as a first metal layer 1 having a thickness T1 of 100 μm, and Ni orientation is used as a second metal layer 2 having a thickness T2 of 30 μm. The foil was bonded to produce a tape-shaped film-forming alignment substrate 5A having a width W of 10 mm.

  The orientation of the Ni orientation foil of this film-forming orientation substrate 5A was examined by X-ray pole figure measurement. The result is shown in FIG.

  Referring to FIG. 5, peaks indicating in-plane orientation were observed on the map, and in particular, four diffraction peaks of the Ni (111) plane were observed on the circumference of α = 45 °. . Moreover, the full width at half maximum (FWHM) which shows in-plane orientation property is 15.4 degrees, and it turned out that favorable orientation property is maintained.

  The half-wave height full width value is the half width of the diffraction peak, and the smaller this value is, the better the in-plane orientation is.

  Further, as a result of producing the superconducting wire 10B shown in FIG. 2 using this oriented film forming substrate 5A and measuring the yield stress, a yield stress of 480 MPa or more was obtained, and pure Ni or Ni—W alloy was used as the substrate. As compared with the superconducting wire, a much higher strength can be achieved while maintaining a highly oriented structure.

Hereinafter, Example 2 will be described with reference to the drawings.
Referring to FIG. 3, SUS316L (JIS-regulated stainless steel) is bonded to SUS316L as a first metal layer 1 having a thickness T1 of 100 μm, and Cu-oriented foil is bonded as a first layer 2a having a thickness T2a of 18 μm, A Ni film was formed by plating as a second layer 2b having a thickness T2b of 1 μm on the Cu-oriented foil to produce a tape-shaped film-forming alignment substrate 5B having a width W of 10 mm.

  The orientation of the Cu orientation foil and the Ni film of the orientation substrate for film formation 5B was examined by X-ray pole figure measurement. The results are shown in FIG. 6 for the Cu oriented foil and in FIG. 7 for the Ni film.

  In both FIG. 6 and FIG. 7, a peak indicating in-plane orientation is observed on the map. In particular, in FIG. 6, the diffraction peak of the Cu (111) plane on the circumference of α = 45 °. However, in FIG. 7, four diffraction peaks on the Ni (111) plane were observed. Further, the full width at half maximum (FWHM) indicating the in-plane orientation is 9.3 ° for the Cu oriented foil of FIG. 6 and 9.9 for the Ni film of FIG. It was found that good orientation was maintained.

  Moreover, as a result of producing the superconducting wire 10B shown in FIG. 4 using this film-forming alignment substrate 5B and measuring the yield stress, a yield stress of 480 MPa or more was obtained, and pure Ni or Ni—W alloy was used as the substrate. As compared with the superconducting wire, a much higher strength can be achieved while maintaining a highly oriented structure.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention can be advantageously applied particularly to an alignment substrate for film formation and a superconducting wire having a superconducting film formed on the alignment substrate for film formation.

  DESCRIPTION OF SYMBOLS 1 1st metal layer, 2nd 2nd metal layer, 2a 1st layer, 2b 2nd layer, 3 intermediate | middle layer, and superconducting film, 5A, 5B orientation substrate for film formation, 10A, 10B superconducting wire.

Claims (4)

A first metal layer made of non-oriented and non-magnetic stainless steel;
A second metal layer having a texture that is bonded to the first metal layer and at least a surface layer is oriented,
The first metal layer has a higher strength than the second metal layer;
The second metal layer includes a surface-side second metal layer bonded to the surface of the first metal layer and a back-side second metal layer bonded to the back surface of the first metal layer. And the second metal layer on the front side and the second metal layer on the back side are separated from each other,
Each of the second metal layer on the front surface side and the second metal layer on the back surface side includes a first layer and a second layer stacked on each other, and the first layer is the first layer. 2 is located on the first metal layer side of the second layer, the second layer is located on the surface layer side of the first layer ,
The first layer of each of the front-side and back-side second metal layers is made of copper, and the second layer of each of the front-side and back-side second metal layers is nickel or a nickel alloy are becoming more, the orientation substrate for film formation.   The alignment substrate for film formation according to claim 1, wherein at least the surface layer of each of the second metal layer on the front side and the back side has a cubic texture. 3. A superconducting wire, wherein an intermediate layer and a superconducting film are formed on each of the second metal layer on the front side and the back side of the alignment substrate for film formation according to claim 1 or 2 . The superconducting wire according to claim 3 , wherein the yield stress is 480 MPa or more.

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