JP5663230B2 - Oxide superconducting wire and method for producing the same - Google Patents

Description

  The present invention relates to an oxide superconducting wire having a laminated structure including an intermediate layer, an oxide superconducting layer, and a stabilizing layer on a substrate, and a method for producing the same.

RE-123 oxide superconductor discovered in recent years (REBa ₂ Cu ₃ O _{7-X, where} RE is a rare earth element including Y) exhibits superconductivity above liquid nitrogen temperature and has low current loss. It is considered as a very promising material for practical use, and it is desired to process it into a wire and use it as a power supply conductor or a magnetic coil. As a method for processing this oxide superconductor into a wire, a metal having high strength, heat resistance, and easy to process into a wire is processed into a long tape shape, and this metal base tape is Methods for forming oxide superconducting layers have been studied.

  Furthermore, since the oxide superconductor has electrical anisotropy, it is necessary to control crystal orientation when forming an oxide superconducting layer on the substrate. A technique is known in which an oxide superconducting layer is stacked on an intermediate layer. As an example of a technique using this intermediate layer, an ion beam assisted deposition method (IBAD method: Ion Beam Assisted Deposition) is known. This method uses constituent particles struck from a target by a sputtering method on a substrate. It is known as a method of depositing an intermediate layer while simultaneously irradiating argon ions generated from an ion gun or the like from an oblique direction (for example, 45 degrees direction). According to this IBAD method, an intermediate layer exhibiting high biaxial orientation can be formed on a base material. Therefore, by forming an oxide superconducting thin film on this intermediate layer, an oxide superconducting conductor having excellent superconducting properties. Can be obtained.

  Further, in the oxide superconducting conductor, a thin silver stabilizing layer is formed on the oxide superconducting layer, and a thick stabilizing layer made of a highly conductive metal material such as copper is provided thereon. A structure in which a stabilization layer having a layer structure is stacked is employed. As an example of a technique for forming the stabilization layer having the two-layer structure, a thin Ag stabilization layer is formed on the oxide superconducting layer by sputtering, and the whole is immersed in an aqueous copper sulfate solution. A technique for forming a Cu stabilization layer on an Ag stabilization layer by electroplating using an aqueous copper solution as a plating bath is known. (See Patent Document 1)

  The Ag stabilizing layer is also provided for the purpose of adjusting fluctuations in the amount of oxygen when the oxide superconducting layer is subjected to oxygen heat treatment, and the Cu stabilizing layer is formed from the superconducting state of the oxide superconducting layer. It is provided for the purpose of functioning as a bypass for commutating the current in the oxide superconducting layer when attempting to transition to the normal conducting state.

  Further, in the oxide superconductor, a structure composed of a substrate, a buffer layer, a multifilament superconductor layer, and a stabilization layer as a structure in which a stabilization layer is combined, and a plurality of multifilament superconductor layers provided on the substrate are provided. A structure encapsulated by a metal stabilization layer is known. (See Patent Document 2)

JP 2007-80780 A Special table 2009-544144

  In the prior art, when an Ag stabilization layer is formed on an oxide superconducting layer, it may be formed by a sputtering method, but in the Ag film formation by a sputtering method, the upper surface side of the oxide superconducting layer is formed. Although film formation is possible, there is a problem that other than that, for example, the stabilization layer cannot be satisfactorily formed on the side surface of the oxide superconducting layer. For this reason, in the prior art in which the electrolytic plating is performed, a portion where there is no Ag stabilizing layer in the process of immersing the wire in the copper sulfate solution, such as the side surface side of the oxide superconducting layer, the side surface side of the intermediate layer, etc. Since the portion is directly immersed in the copper sulfate solution, the immersed portion of the oxide superconducting layer or the intermediate layer may be deteriorated.

Even if the portion not covered by the Ag stabilization layer is not damaged significantly, a Cu plating layer is preferentially deposited on the Ag stabilization layer, so that the side surface side of the oxide superconducting layer is Considering the cover, etc., it is necessary to increase the plating time so that the Cu plating layer is sufficiently grown and the plating layer reaches the side of the oxide superconducting layer. There is a problem that becomes longer.
On the other hand, in the prior art, in the technique of encapsulating the Ag stabilizing layer around the entire circumference of the oxide superconducting wire, the above-mentioned problems can be solved, but expensive Ag is attached to the entire circumference of the superconducting wire. There is a problem that an increase in cost is inevitable.

  The present invention has been made in view of the above-described conventional situation, and an Al hot-dip plating layer is formed on the peripheral surface of an oxide superconducting laminate comprising a base material, an intermediate layer, an oxide superconducting layer, and an Ag stabilizing base layer. Oxide superconducting laminate including the side of the oxide superconducting layer while reducing the amount of Ag used and avoiding cost increases An object of the present invention is to provide a structure in which the peripheral surface of the body is protected by covering with an Al hot-dip plating layer and a metal stabilization layer.

In order to solve the above problems, the present invention comprises a base material, an intermediate layer and an oxide superconducting layer provided on the base material, and an Ag stabilizing base layer provided on the oxide superconducting layer. The oxide superconducting laminate is configured, and the peripheral surface side of the oxide superconducting laminate is coated with an Al molten plating layer covering the entire peripheral surface, and the outer peripheral side of the Al molten plated layer is made of metal by electrolytic plating. The stabilizing layer is laminated.
In the present invention, it is preferable that the thickness of the Al hot-dip plating layer is in the range of 1 to 20 μm.

The production method of the present invention comprises a base material, an intermediate layer provided on the base material, an oxide superconducting layer, and an Ag stabilizing base layer provided on the oxide superconducting layer. A laminated body is configured, and an Al hot-dip plating layer covering the entire peripheral face is coated on the peripheral face side of the oxide superconducting laminate, and a metal stabilization layer by electrolytic plating is provided on the outer peripheral side of the Al hot-dip plating layer. A method of manufacturing a laminated oxide superconducting wire, wherein the oxide superconducting laminate is dipped in a molten aluminum and pulled up to cover the entire circumference of the oxide superconducting laminate with a predetermined thickness of Al melt After the plating layer is formed, the Cu stabilization layer is formed on the entire circumference of the Al hot-dip plating layer by being immersed in an electrolytic plating solution of Cu and performing electrolysis.
In the manufacturing method of this invention, it is preferable to make the thickness of the said Al hot dipping layer into the range of 1-20 micrometers.

According to the present invention, the surface side of the oxide superconducting layer formed on the base material is protected by being covered with the stabilizing base layer of Ag, and the side surface side of the oxide superconducting layer, the back surface side of the base material, and the Ag The surface side of the stabilizing base layer, that is, the entire circumference of the oxide superconducting laminate is covered with an Al hot-dip plating layer to protect it, so that the oxide superconducting laminate and the side surface side of the intermediate layer are plated when the stabilizing layer is formed by electrolytic plating. There is no risk of being immersed in the liquid, and deterioration of superconducting characteristics can be prevented.
Since the Al molten plating layer covers almost the entire periphery of the oxide superconducting laminate, the adhesion of the stabilization layer formed by electrolytic plating formed on the outer peripheral side of the Al molten plated layer is improved.
By making the thickness of the Al hot-dipped layer in the range of 1 to 20 μm, the protection of the side surface of the oxide superconducting laminate is sufficient, and stable plating can be performed all around the electrolytic plating, and there is no uneven electrolysis. A stabilization layer by a plating layer can be obtained.

1 is a schematic cross-sectional view showing a first embodiment of an oxide superconducting wire according to the present invention. FIG. 2 is a schematic cross-sectional view of an oxide superconducting laminate incorporated in the oxide superconducting wire shown in FIG. 1. The block diagram which shows in detail the layer structure of the oxide superconducting laminated body shown in FIG. Explanatory drawing which shows an example of the apparatus structure for implementing an ion beam assist film-forming method, and a film-forming state. Explanatory drawing which shows the state which immerses and raises an oxide superconducting laminated body in the molten aluminum in a molten Al tank.

Hereinafter, embodiments of an oxide superconducting wire according to the present invention will be described with reference to the drawings.
FIG. 1 is a schematic perspective view schematically showing the oxide superconducting wire 1 according to the first embodiment of the present invention, and FIG. 2 is an outline of the oxide superconducting laminate 2 incorporated in the oxide superconducting wire 1. FIG. 3 is a block diagram showing details of the laminated structure of the oxide superconducting laminate 2.
The oxide superconducting laminate 2 is formed by laminating an intermediate layer 5, an oxide superconducting layer 6 and a stabilizing base layer 7 on a tape-like substrate 3, and this oxide superconducting laminate 2 is provided at the center. A stabilizing layer 9 made of an Al hot-dip plating layer 8 and an electrolytic plating layer of Cu is formed so as to cover the entire peripheral surface, and a resin coating layer 10 is formed so as to cover the entire peripheral surface of the stabilizing layer 9, An oxide superconducting wire 1 is configured.
In more detail, the oxide superconducting laminate 2 is formed by laminating an intermediate layer 5 comprising a diffusion prevention layer 11, a bed layer 12, an alignment layer 15 and a cap layer 16 on the upper surface of a base material 3, as shown in FIG. The oxide superconducting layer 6 and the stabilizing base layer 7 are laminated thereon. In FIG. 1 and FIG. 2, the intermediate layer 5 is drawn as one layer for the sake of simplicity. The diffusion preventing layer 11 and the bed layer 12 are not essential and may be omitted depending on circumstances.

  The base material 3 can be used as a base material of a normal superconducting wire, has only to be high strength, is preferably in the form of a tape for making a long cable, and is made of a heat-resistant metal. Is preferred. Examples thereof include various metal materials such as nickel alloys such as stainless steel and hastelloy, or ceramics arranged on these various metal materials. Among various heat resistant metals, nickel alloys are preferable. Especially, if it is a commercial item, Hastelloy (trade name made by US Haynes Co., Ltd.) is suitable. Any type can be used. What is necessary is just to adjust the thickness of the base material 3 suitably according to the objective, Usually, it can be set as the range of 10-500 micrometers.

The diffusion prevention layer 11 is formed for the purpose of preventing the diffusion of the constituent elements of the base material 3, and silicon nitride (Si ₃ N ₄ ), aluminum oxide (Al ₂ O ₃ , also referred to as “alumina”), or consists _{GZO (Gd 2 Zr 2 O 7} ) or the like, a thickness of 10~400nm example. When the thickness of the diffusion preventing layer 11 is less than 10 nm, there is a possibility that the diffusion of the constituent elements of the substrate 3 cannot be sufficiently prevented. On the other hand, when the thickness of the diffusion preventing layer 11 exceeds 400 nm, the internal stress of the diffusion preventing layer 11 increases, and there is a possibility that the whole including the other layers is easily peeled off from the substrate 3. Further, since the crystallinity of the diffusion preventing layer 11 is not particularly limited, it may be formed by a film forming method such as a normal sputtering method.

The bed layer 12 has high heat resistance and is intended to reduce interfacial reactivity, and is used to obtain the orientation of a film disposed thereon. Such a bed layer 12 is, for example, a rare earth oxide such as yttria (Y ₂ O ₃ ), and is represented by a composition formula (α ₁ O ₂ ) _2x (β ₂ O ₃ ) _(1-x). It can be illustrated. More _{specifically, Er 2 O 3, CeO 2} , Dy 2 O 3, Er 2 O 3, Eu 2 O 3, Ho 2 O 3, can be exemplified _La 2 _{O 3} and the like. The bed layer 12 is formed by a film forming method such as a sputtering method, and has a thickness of 10 to 100 nm, for example. Further, since the crystallinity of the bed layer 12 is not particularly limited, it may be formed by a film forming method such as a normal sputtering method.

The alignment layer 15 may have either a single layer structure or a multi-layer structure, and is selected from materials that are biaxially aligned in order to control the crystal orientation of the cap layer 16 laminated thereon. Specifically, preferred materials for the alignment layer 15 are Gd ₂ Zr ₂ O ₇ , MgO, ZrO ₂ —Y ₂ O ₃ (YSZ), SrTiO ₃ , CeO ₂ , Y ₂ O ₃ , Al ₂ O ₃ , Gd _2. Examples thereof include metal oxides such as O ₃ , Zr ₂ O ₃ , Ho ₂ O ₃ , and Nd ₂ O ₃ .
If the orientation layer 15 is formed with a good crystal orientation (for example, a crystal orientation degree of 15 ° or less) by an IBAD (Ion-Beam-Assisted Deposition) method, the crystal orientation of the cap layer 16 formed thereon is increased. A good value (for example, a degree of crystal orientation of about 5 °) can be obtained, and thereby the superconducting characteristics can be exhibited with good crystal orientation of the oxide superconducting layer 6 formed on the cap layer 16. The oxide superconducting layer 6 can be obtained.
For example, the alignment layer 15 made of Gd ₂ Zr ₂ O ₇ , MgO, or ZrO ₂ —Y ₂ O ₃ (YSZ) has a small value of Δφ (FWHM: full width at half maximum) that is an index indicating the degree of crystal orientation in the IBAD method. This is particularly preferable because it can be performed.

The alignment layer 15 by the IBAD method is formed by, for example, the apparatus shown in FIG.
The apparatus shown in FIG. 4 includes a running system (not shown) for running the tape-like base material 3 provided with the diffusion prevention layer 11 and the bed layer 12 in the longitudinal direction, and the surface thereof is on the surface of the base material 3. A target 21 that is opposed obliquely to the surface, a sputter beam irradiation device 22 that irradiates the target 21 with ions, and ions (mixed ions of rare gas ions and oxygen ions) obliquely with respect to the surface of the substrate 3. These devices are arranged in a vacuum vessel (not shown).

In order to form the alignment layer 15 on the bed layer 12 of the substrate 3 using the apparatus shown in FIG. 4, the inside of the vacuum vessel is set in a reduced pressure atmosphere, and the sputter beam irradiation apparatus 22 and the ion source 23 are operated. As a result, the target 21 is irradiated with ions from the sputtering beam irradiation apparatus 22, and the constituent particles of the target 21 are beaten or evaporated to be deposited on the bed layer 12. At the same time, mixed ions of rare gas ions and oxygen ions are radiated from the ion source 23 and irradiated onto the surface of the substrate 3 (bed layer 12) at a predetermined incident angle (θ).
In this way, by irradiating ions at a predetermined incident angle while depositing the constituent particles of the target 21 on the surface of the bed layer 12, the specific crystal axis of the formed sputtered film is fixed in the ion incident direction. Then, the c-axis of the crystal is oriented in a direction perpendicular to the surface of the metal substrate, and the a-axis and b-axis of the crystal are oriented in a certain direction in the plane. Therefore, the alignment layer 102 formed on the bed layer 12 by the IBAD method can obtain a high in-plane alignment degree, for example, Δφ = 12 to 16 °.

Next, the cap layer 16 is epitaxially grown by being formed on the surface of the alignment layer 15 in which the in-plane crystal axes are oriented as described above, and thereafter the grains are grown in the lateral direction so that the crystal grains are in the in-plane direction. material capable of self-orientation, a is not particularly limited as long as it, specifically as _{preferred, CeO 2, Y 2 O 3} , Al 2 O 3, Gd 2 O 3, ZrO 2, Ho 2 O 3, Nd 2 O ₃ etc. can be illustrated. When the material of the cap layer is CeO ₂ , the cap layer may contain a Ce—M—O-based oxide in which part of Ce is substituted with another metal atom or metal ion.
For example constituted by CeO _2. Since the cap layer 16 is self-aligned as described above, a higher in-plane orientation degree, for example, Δφ = about 4 to 6 °, can be obtained.

For example, the CeO ₂ layer can be formed by a PLD method (pulse laser deposition method), a sputtering method, or the like, but it is desirable to use the PLD method in that a high film formation rate can be obtained. The film formation conditions for the CeO ₂ layer by the PLD method can be performed in an oxygen gas atmosphere at a substrate temperature of about 500 to 1000 ° C. and about 0.6 to 100 Pa.
The film thickness of the CeO ₂ layer may be 50 nm or more, but is preferably 100 nm or more in order to obtain sufficient orientation. However, if it is too thick, the crystal orientation deteriorates, so that it can be in the range of 50 to 5000 nm, more preferably in the range of 100 to 5000 nm.

The oxide superconducting layer 6 may be a known one, and specifically, a material made of REBa ₂ Cu ₃ O _y (RE represents a rare earth element such as Y, La, Nd, Sm, Er, Gd) is exemplified. it can. Examples of the oxide superconducting layer 6 include Y123 (YBa ₂ Cu ₃ O _7-X ) or Gd123 (GdBa ₂ Cu ₃ O _7-X ).
The oxide superconducting layer 6 is laminated by a physical vapor deposition method such as sputtering, vacuum vapor deposition, laser vapor deposition, electron beam vapor deposition, chemical vapor deposition (CVD), or thermal coating decomposition (MOD). In particular, from the viewpoint of productivity, the PLD (pulse laser deposition) method, the TFA-MOD method (organic metal deposition method using trifluoroacetate, coating pyrolysis method) or the CVD method may be used. it can.

  Here, as described above, when the oxide superconducting layer 6 is formed on the cap layer 16 having a good orientation, the oxide superconducting layer 6 laminated on the cap layer 16 also matches the orientation of the cap layer 16. Crystallize as follows. Therefore, the oxide superconducting layer 6 formed on the cap layer 16 is hardly disturbed in crystal orientation, and in each of the crystal grains constituting the oxide superconducting layer 6, the thickness of the base material 10 is reduced. The c-axis that hardly allows electricity to flow is oriented in the vertical direction, and the a-axis or the b-axis is oriented in the length direction of the substrate 10. Therefore, the obtained oxide superconducting layer 6 is excellent in quantum connectivity at the crystal grain boundary, and hardly deteriorates in the superconducting characteristics at the crystal grain boundary. High critical current density can be obtained.

The stabilizing base layer 7 laminated on the oxide superconducting layer 6 is formed as a layer made of a metal material having good conductivity such as Ag and low contact resistance with the oxide superconducting layer 6.
The reason why the stabilization base layer 7 is made of Ag is that it has the property of making it difficult for the oxygen doped in the oxide superconducting layer 6 to escape from the oxide superconducting layer 6 in the annealing step of doping the oxide superconducting layer 6 with oxygen. . In order to form the Ag stabilizing base layer 7, a film forming method such as a sputtering method is employed, and the thickness thereof can be formed to about 1 to 30 μm.

The oxide superconducting laminate 2 having the structure shown in FIG. 2 and FIG. 3 covers and covers the upper surface of the oxide superconducting layer 6 with an Ag stabilizing base layer 7. If the oxide superconducting layer 6 is not protected and exposed, the characteristics of the oxide superconducting layer 6 may be deteriorated due to moisture or the like, and the exposed portion of the oxide superconducting layer 6 is damaged in the subsequent process. In consideration of the possibility that the characteristics will deteriorate, it is necessary to protect it with some kind of cover.
In the present embodiment, in order to protect the oxide superconducting layer 6, an Al hot-dip plating layer 8 by Al hot-dip plating and a Cu stabilization layer 9 by electrolytic plating described below are formed to form the oxide superconducting laminate 2. Adopt a structure that covers the entire circumference.

As described so far for the manufacturing process of the oxide superconducting laminate 2, each layer of the diffusion prevention layer 11, the bed layer 12, the alignment layer 15, and the cap layer 16 is formed on the tape-like long base material 10. In the process of forming a film, a film forming method performed by controlling the atmosphere in a vacuum atmosphere is used to move the tape-like long base material 10 within the film forming apparatus, and several hundred degrees Celsius as necessary. Each layer is formed while being repeatedly heated to a high temperature. However, depending on the layer to be formed, the side surface side and the back surface side of the base material 10 are repeatedly exposed to a film forming atmosphere. Heated.
For this reason, unnecessary deposits and high-temperature products are formed on the side surface side and the back surface side of the base material 1 through the process of forming the diffusion prevention layer 11, the bed layer 12, the alignment layer 15, and the cap layer 16. In the case where the material constituting the substrate 1 is Hastelloy, in consideration of the fact that the electroplating is particularly bad, the Al hot-dip plating layer 8 is formed into a tape-like shape by Al hot-dip plating. A necessary thickness is formed so as to cover the entire circumference of the oxide superconducting laminate 2.
As an example of means for forming the Al molten plating layer 8, a guide member comprising a molten aluminum (molten Al bath) 31 in a melting tank 30 shown in FIG. 5 and a heat resistant metal roller provided inside the molten aluminum 31. While the oxide superconducting laminate 2 is caused to travel through 32 and passes through the inside of the molten aluminum 31, the Al molten plating layer 8 having a required thickness can be formed on the peripheral surface of the oxide superconducting laminate 2. The coating thickness of the Al hot-dipped layer 8 can be adjusted by adjusting the speed and time when the oxide superconducting laminate 2 passes through the molten aluminum 31. The temperature of the aluminum melt 31 can be about 680-710 degreeC, for example. The molten metal constituting the molten aluminum 31 may be pure Al or recycled Al, or may be an Al alloy molten metal to which an additive element that does not adversely affect the oxide superconducting layer 6 is added.
The film thickness of the Al hot-dip plating layer 8 formed here is preferably in the range of 1 μm to 20 μm, and more preferably in the range of 1 to 10 μm.

If the thickness of the Al hot-dipped layer 8 is less than 1 μm, unevenness tends to occur on the back side of the base material 1 particularly when the entire surface of the oxide superconducting laminate 2 is covered and the Al hot-dipped layer 8 is thick. When unevenness occurs, when forming the Cu stabilizing layer 9 on the Al hot-dip plated layer 6 by electrolytic plating, it causes electrolytic concentration to hinder electrolytic plating, or causes the unevenness of electrolytic plating. Become.
When the thickness of the Al hot-dipped layer 8 exceeds 20 μm, it becomes too thick and hard, and flexibility is likely to be lost, partial stress concentration is likely to occur, and distortion that degrades the superconducting characteristics occurs. This causes malfunctions. Further, when the thickness of the Al hot-dipped layer 8 exceeds 20 μm, the time for immersing the oxide superconducting laminate 2 in the molten aluminum 31 at a high temperature (about 640 to 710 ° C.) described later becomes longer. There is a possibility that the superconducting laminate 2 may deteriorate in characteristics due to the heat of the molten aluminum 31.

  According to the oxide superconducting wire 1 of the present embodiment described above, the surface side of the oxide superconducting layer 6 formed on the base material 3 via the intermediate layer 5 is covered and protected by the Ag stabilizing base layer 7. In addition, both sides of the oxide superconducting layer 6 and the back side of the base material 3 and the surface side of the Ag stabilizing base layer 7, that is, the entire circumference of the oxide superconducting laminate 2 are covered with an Al molten plating layer 8 for protection. Therefore, when forming the stabilization layer 9 that is immersed in a copper sulfate solution and electrolytically processed when performing electrolytic plating of Cu, both sides of the oxide superconducting laminate 2, that is, both sides of the intermediate layer 15, Specifically, the diffusion preventing layer 11, the bed layer 12, the alignment layer 15, the cap layer 16 and the both sides of the oxide superconducting layer 6 are not susceptible to being immersed in the copper sulfate solution, and the superconducting characteristics are improved. Deterioration can be prevented. Further, since the entire peripheral surface of the oxide superconducting laminate 2 can be completely covered with the Al hot-dip plating layer 8 and the Cu stabilizing layer 9, the oxide superconducting wire 1 can be used in a humid atmosphere for a long period of time. However, the risk of moisture entering the oxide superconducting layer 6 side can be avoided, and deterioration of the characteristics of the oxide superconducting wire 1 can also be prevented.

In the oxide superconducting wire 1 of this embodiment, since the Al hot-dipped layer 8 covers almost the entire circumference of the oxide superconducting laminate 2 without unevenness, the outer periphery of the Al hot-dipped layer 8 is subjected to electrolytic plating. Since the electroplating is improved and the electroplating can be performed without unevenness, the stabilization layer 9 can be formed without unevenness in thickness, and the adhesion of the stabilization layer 9 can be improved.
Further, by setting the thickness of the Al hot-dipped layer 8 within a suitable range of 1 to 20 μm, the side surface side of the oxide superconducting laminate 2 is sufficiently protected, and stable plating during electrolytic plating can be performed all around. Therefore, the oxide superconducting wire 1 having the stabilizing layer 9 which is an electroplating layer without unevenness can be obtained.

"Example 1"
A tape-shaped substrate having a width of 10 mm, a thickness of 0.1 mm, and a length of 1000 mm made of Hastelloy C276 (trade name of Haynes, USA) was prepared, and the surface of the tape-shaped substrate was coated with alumina abrasive grains having an average particle diameter of 3 μm. And polished to a mirror finish.
The tape substrate was degreased and washed using an organic solvent of ethanol and acetone.
Next, a diffusion prevention layer having a thickness of 100 nm made of Al ₂ O ₃ is formed on the surface of the tape substrate by using ion beam sputtering, and further made of Y ₂ O ₃ by using ion beam sputtering. A bed layer having a thickness of 30 nm was formed. In carrying out the ion beam sputtering method, the tape-like base material is wound around a reel inside the sputtering apparatus, and can be formed while being fed from one reel to the other reel, over the entire length of the tape-like base material, A diffusion prevention layer and a bed layer were formed.
Next, an IBAD method was performed using an ion beam assisted sputtering apparatus having a structure shown in FIG. 4, and an MgO alignment layer having a thickness of 5 to 10 nm was formed on the bed layer by ion beam assisted deposition. In this case, the incident angle of the assist ion beam was set to 45 ° with respect to the normal line of the tape-shaped substrate film forming surface. In carrying out the IBAD method, the tape-like base material is wound around a reel inside the sputtering apparatus, and the film is formed while being fed from one reel to the other reel so that the entire length of the tape-like base material is covered with MgO. An alignment layer was formed.

Subsequently, a cap layer of CeO _{2 having} a thickness of 500 nm was formed on the MgO alignment layer using a pulsed laser deposition method (PLD method). Further, an oxide superconducting layer having a thickness of 1 μm of GdBa ₂ Cu ₃ O _7-x was formed on the cap layer by a pulse laser deposition method. In carrying out the pulse laser deposition method, a film-formation apparatus was formed while a tape-shaped substrate was supplied from reel to reel. Next, a 10 μm thick Ag was formed on the oxide superconducting layer by sputtering. A stabilizing base layer was formed. Also in this sputtering method, a film can be formed while a tape-shaped substrate is supplied from reel to reel. Next, oxygen annealing was performed at 500 ° C. and then taken out. By the above method, an oxide superconducting laminate having a structure including a diffusion preventing layer, a bed layer, an orientation layer, a cap layer, an oxide superconducting layer, and a stabilizing base layer was formed on a long tape-like substrate.

The oxide superconducting laminate is wound on a reel, and immersed in an Al bath at 700 ° C. by feeding out from the reel, and after passing through an Al bath via a heat-resistant metal reel provided in the Al bath, The oxide superconducting laminate was dipped in an Al bath and wound up on another reel provided outside the Al bath, and then Al hot dipping was performed. The moving speed of the oxide superconducting laminate when passing through the Al bath is adjusted within a range of 2 to 3 m / min, and the time during which the oxide superconducting laminate is immersed in the Al bath is 4 seconds to 6 seconds. The film thickness of the Al hot dipping layer was adjusted by adjusting the gap between the two.
By this Al hot dipping treatment, an Al hot dipped layer having a film thickness shown in Table 1 below was formed so as to cover the entire peripheral surface of the oxide superconducting laminate.
Next, the oxide superconducting laminate after the formation of the Al molten plating layer was immersed in a plating solution of an aqueous copper sulfate solution to perform electrolytic Cu plating, thereby forming a 5 μm thick Cu electrolytic plating layer. When immersed in an aqueous copper sulfate solution, the oxide superconducting laminate provided with an Al molten plating layer is drawn out from the reel and immersed in the electrolytic plating solution, and then drawn out from the plating solution and wound on another reel to obtain an Al molten plating layer. A stabilization layer made of an electrolytic plating layer of Cu was formed over the entire length of the tape-shaped oxide superconducting laminate including

  As is clear from the results shown in Table 1, if the thickness of the Al hot-dip plating layer is in the range of 1 to 20 μm, there is no unevenness of the Al hot-dip plating layer, and thus a stabilization layer that is an electrolytic plating layer of Cu. It has become clear that it is possible to provide an oxide superconducting wire that does not cause unevenness and does not cause deterioration of superconducting characteristics.

"Example 2"
Substantially the same steps as in Example 1 are performed to form an oxide superconducting laminate, and the oxide superconducting laminate before being subjected to Al hot dipping treatment is oxidized by atmospheric pressure (atmospheric pressure) plasma treatment. The whole superconducting laminate was treated with plasma, and thereafter, an Al hot-dip plating layer and an electrolytic plating layer were formed.

  As a result, the wettability on the back surface side of the base material was improved, and the proportion of unevenness of the Al hot dip plating generated on the back surface side of the base material was reduced even in the sample in which the 0.5 μm thick Al hot dip layer was formed. From this, it is exposed to the film-forming atmosphere when forming the diffusion prevention layer, the bed layer, the orientation layer, the cap layer, the oxide superconducting layer, and the stabilizing base layer, and various materials are applied to the back side of the substrate of the oxide superconducting laminate. Even if impurities and precipitates exist, the surface activity of the oxide superconducting laminate can be improved by atmospheric pressure plasma treatment, which eliminates unevenness of the Al hot-dip plating layer and the electrolytic plating layer. It has been found that an oxide superconducting wire with good plating adhesion can be provided.

  The present invention can be used for an oxide superconducting wire used in various electric power devices such as a superconducting motor and a current limiting device.

  DESCRIPTION OF SYMBOLS 1 ... Oxide superconducting wire, 2 ... Oxide superconducting laminated body, 3 ... Base material, 5 ... Intermediate | middle layer, 6 ... Oxide superconducting layer, 7 ... Stabilization base layer, 8 ... Al hot dip plating layer, 9 ... Electrolytic plating layer DESCRIPTION OF SYMBOLS 10 ... Coating layer, 11 ... Diffusion prevention layer, 12 ... Bed layer, 15 ... Orientation layer, 16 ... Cap layer, 21 ... Target, 22 ... Sputter beam irradiation apparatus, 23 ... Ion source, 30 ... Al melting tank, 31 ... Molten aluminum (molten Al bath).

Claims (4)

  An oxide superconducting laminate comprising a base material, an intermediate layer provided on the base material, an oxide superconducting layer, and an Ag stabilizing base layer provided on the oxide superconducting layer; The peripheral surface side of the oxide superconducting laminate is covered with an Al hot-dip plating layer covering the entire peripheral surface, and a metal stabilization layer is formed by electrolytic plating on the outer peripheral side of the Al hot-dip plating layer. Oxide superconducting wire.   2. The oxide superconducting wire according to claim 1, wherein the thickness of the Al hot-dip plating layer is in the range of 1 to 20 [mu] m.   An oxide superconducting laminate comprising a base material, an intermediate layer provided on the base material, an oxide superconducting layer, and an Ag stabilizing base layer provided on the oxide superconducting layer; An oxide superconducting structure in which an Al molten plating layer covering the entire peripheral surface is coated on the peripheral surface side of the oxide superconducting laminate, and a metal stabilization layer is formed on the outer peripheral side of the Al molten plating layer by electrolytic plating. A method of manufacturing a wire, wherein the oxide superconducting laminate is dipped in a molten aluminum and pulled up, and after forming an Al molten plating layer having a predetermined thickness covering the entire circumference of the oxide superconducting laminate, A method for producing an oxide superconducting wire, characterized in that a Cu stabilizing layer is formed on the entire circumference of an Al hot-dip plating layer by being immersed in an electrolytic plating solution of Cu and electrolyzing.   The method for producing an oxide superconducting wire according to claim 3, wherein the thickness of the Al hot-dip plating layer is in the range of 1 to 20 μm.

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