JP5695921B2 - Manufacturing method of oxide superconducting wire and oxide superconducting wire - Google Patents

Description

  The present invention relates to a method for producing an oxide superconducting wire having a laminated structure in which an intermediate layer, an oxide superconducting layer, and a stabilizing layer are provided on a metal substrate, and an oxide superconducting wire.

The RE-123 oxide superconductor (REBa ₂ Cu ₃ O _7-X : RE is a rare earth element including Y) exhibits superconductivity at a liquid nitrogen temperature and has low current loss. Application development has been made as a conductor for coils. As an example of a method for processing this oxide superconductor into a wire, a metal having a high strength, heat resistance, and easy to process into a wire is processed into a long tape, and this metal base tape A technique for forming an oxide superconducting layer thereon is provided.

  In addition, since the oxide superconductor crystals have electrical anisotropy, it is necessary to control the crystal orientation when forming the oxide superconducting layer on the base tape. A technique for laminating an oxide superconducting layer on a base material via an intermediate layer has been implemented. As an example of a technique using this intermediate layer, an ion beam assisted film formation method (IBAD method: Ion Beam Assisted Deposition) is known, and an intermediate layer exhibiting high biaxial orientation by this IBAD method is formed on a substrate. An oxide superconducting conductor having excellent superconducting properties can be obtained by forming an oxide superconducting layer on the intermediate layer.

  In order to obtain the target line width in this kind of oxide superconductor, prepare a base tape of the target line width from the start of production, and then form an intermediate layer and an oxide superconducting layer thereon, An oxide superconducting wire is manufactured by forming a stabilizing layer, or a base tape having a certain line width is prepared in advance, and an intermediate layer and an oxide superconducting layer are formed thereon, and the stabilizing layer is formed. Research has been made on a method of forming a superconducting oxide to form an oxide superconducting conductor and then cutting it to have a desired line width. In addition, considering the ease of manufacturing and the ability to handle various line widths among these manufacturing methods, an oxide superconducting conductor is prepared in advance with a constant line width, and then cut to the target line width. It is considered that the method of using an oxide superconducting wire is advantageous in terms of production efficiency.

Conventionally, as an example of a method for cutting an oxide superconductor, using a cutter bit having a plurality of sets of two cutting portions, the tape-shaped oxide superconducting conductor is mechanically sandwiched by the cutting edge of the cutting portion of the cutter bit, A method of cutting a plurality of oxide superconducting wires along the width direction of the oxide superconducting conductor has been proposed. (See Patent Document 1)
In addition, a laser beam is irradiated along the length direction of the tape-shaped oxide superconducting conductor, and the oxide superconducting layer is divided by fusing in the width direction, and a plurality of oxide superconducting layers are provided on the substrate. A method of manufacturing an oxide superconducting wire having a structure has been proposed. (See Patent Document 2)

JP 2007-287629 A JP 2007-141688 A

In the conventional method for manufacturing an oxide superconducting wire, when the oxide superconducting conductor is mechanically cut using a cutter tool having a cutting portion as described in Patent Document 1, the oxide superconducting conductor has a laminated structure. Therefore, there is a problem that there is a high possibility that the oxide superconducting layer is peeled or deformed in the vicinity of the cut surface and the superconducting property is deteriorated. Thus, the part where peeling has occurred in the oxide superconducting layer becomes a part that is easily peeled off after cutting, and there is a problem that the peeling strength is lowered.
In the method of irradiating an oxide superconducting conductor with a laser beam and dividing the oxide superconducting layer as described in Patent Document 2, as an example, a pulse laser having a laser frequency of 10 kHz and energy of 4 W is used. Is reduced to about 30 μm and irradiated to the tape-shaped oxide superconducting conductor to melt the oxide superconducting layer.
However, when the present inventor cuts the oxide superconducting conductor having the above-mentioned laminated structure by using this pulse laser and manufactured a plurality of oxide superconducting wires from one oxide superconducting conductor having a predetermined width, It has been found that a corrugated irregular concavo-convex portion is continuously generated in the melted portion from the metal base tape to the Ag stabilizing layer thereabove.

Since the base tape used for the oxide superconducting conductor is made of a high-strength metal, irregular irregularities are continuously formed along the melted portion of the base tape, including the stabilizing layer. If this is the case, the concavo-convex portion is processed into a shape like a blade.
By the way, even if the oxide superconductor is used for a superconducting coil for a superconducting magnet or a superconducting cable for power transmission, it is insulated in any application. For example, as shown in FIG. 7, this insulation treatment is performed on a base material tape 100 made of resin with respect to an oxide superconducting wire 102 having a laminate 101 such as an intermediate layer, an oxide superconducting layer, and a stabilizing layer. This is done by winding the insulating tape 103.
However, as a result of the trial production by the present inventors, when insulating treatment is performed by winding the insulating superconductor wire 103 around the oxide superconducting wire 102 having continuous blade-like uneven portions at both end edges of the base tape 100, the insulating tape 103 is continuously processed. In particular, it has been found that the insulating tape 103 is cut by sharply uneven portions, which makes it difficult to perform the insulation coating.

  The present invention has been made in view of the above-described conventional situation, and even if a method of cutting an oxide superconducting conductor with a laser beam is performed, an uneven portion that becomes an obstacle to insulation treatment is formed on the cut surface of the substrate. An object of the present invention is to provide a method for producing an oxide superconducting wire that can be cut so as not to occur, and an oxide superconducting wire obtained.

In order to solve the above problems, the present invention provides a tape-shaped base material, an intermediate layer provided on the base material, an oxide superconducting layer provided on the intermediate layer, and the oxide superconducting layer. An oxide superconducting conductor having a stabilization layer provided thereon is irradiated with a laser beam from the outside on the stabilization layer forming side along the length direction of the substrate to oxidize the stabilization layer and the oxide superconductor. When an oxide superconducting wire is manufactured by fusing the superconducting layer, the intermediate layer, and the base material to divide the oxide superconducting conductor into multiple parts in the width direction, a laser beam of a continuous wave laser is used as the laser beam. The uneven portion formed on the melt cross section of the substrate by the laser beam of the continuous wave laser is set to 5 μm or less at the maximum height Rz, and is ejected to the oxide superconductor along with the irradiation of the laser beam. seal Gas with the stabilizing layer was melted by the laser beam, the oxide superconducting layer, and the intermediate layer and wherein that you remove blowing a melt of the substrate.
Irradiate a continuous wave laser beam, melt the oxide superconducting conductor including the base material, and divide the oxide superconducting conductor melted by the continuous wave laser laser beam. It is possible to make the uneven portion much smaller than when melted by a conventional pulse laser. For this reason, the fusing part of the oxide superconducting conductor by a laser beam can be formed more smoothly than before. Also, if it is an oxide superconducting wire provided with this smooth fusing part, when insulating treatment is performed by winding an insulating tape around its outer periphery, there is no risk that the insulating tape will be cut by the uneven part of the fusing part, Does not interfere with the insulation treatment of oxide superconducting wire.

If an uneven portion for generating the blown surface of the substrate and the stabilizing layer by Les Zabimu to 5μm or less at the maximum height Rz, it can smoothly form the substrate fusing unit. Therefore, in the case where the oxide superconducting wire is insulated by applying tension so as to surround the melted portion and winding the insulating tape, the insulating tape is not cut.
In the present invention, a step of winding an insulating tape so as to surround the entire periphery of the base material, the intermediate layer, the oxide superconducting layer, and the stabilizing layer after fusing by the continuous wave laser beam can be provided.
The unevenness of the melted cross section of the base material side edge and the stabilization layer side edge is small, and the melt cross section is processed smoothly, so even if an insulating tape is wound around the outer periphery of the oxide superconducting wire by applying tension, The insulation tape does not break. For this reason, the oxide superconducting wire which performed the insulation process by winding of the insulating tape can be obtained.

The oxide superconducting wire of the present invention is provided on a tape-shaped substrate, an intermediate layer provided on the substrate, an oxide superconducting layer provided on the intermediate layer, and the oxide superconducting layer. An oxide superconducting wire formed by fusing a plurality of oxide superconducting conductors having a stabilization layer formed by a laser beam in the width direction thereof, along the length direction of the base material The maximum height Rz of the concavo-convex portion formed in the melted portion by the formed laser beam is 5 μm or less.
If the uneven portion generated on the melted surface of the base material by the laser beam is 5 μm or less at the maximum height Rz, the melted surface of the base material side edge can be made smooth.

The oxide superconducting wire of the present invention is formed by winding an insulating tape so as to surround the laminate of the base material, the intermediate layer, the oxide superconducting layer, and the stabilizing layer.
Since the unevenness of the melted portion on the side edge of the base material is formed to a maximum height Rz of 5 μm or less, the insulating tape is difficult to cut even if the insulating tape is wound with tension applied. For this reason, the insulation coating can be reliably formed by winding the insulating tape.

  ADVANTAGE OF THE INVENTION According to this invention, the smooth oxide superconducting wire of the fusing part which the big uneven | corrugated part has not produced in the fusing part of the base material by a laser beam can be provided.

FIG. 1 is an explanatory diagram showing an example of a state in which an oxide superconducting conductor is melted by a continuous wave laser using a fiber laser device. Schematic which shows the whole structure of the fiber laser apparatus shown in FIG. FIG. 3 shows an oxide superconducting conductor fused by the fiber laser device shown in FIG. 1, FIG. 3 (a) is a perspective view showing an example structure of the oxide superconducting conductor before fusing, and FIG. 3 (b) is after fusing. The perspective view which shows an example structure of an oxide superconducting wire. FIG. 4 is a perspective view showing a state in which an insulating coating with an insulating tape is formed on the oxide superconducting wire after fusing. FIG. 5 is an explanatory view showing an example of an uneven portion formed on the base material of the oxide superconducting wire after fusing. FIG. 6 is an explanatory diagram of a peel test of the oxide superconducting wire manufactured in the example. FIG. 7 is a perspective view showing an example of a state in which an insulating tape is wound around a conventional oxide superconducting wire.

Hereinafter, an embodiment of a method for producing an oxide superconducting wire according to the present invention will be described with reference to the drawings.
FIG. 1 is an explanatory view showing a state where a tape-shaped oxide superconductor is cut by a continuous wave laser based on the method according to the present invention, and FIG. 2 is a diagram of a fiber laser device used for generating the continuous wave laser. FIG. 3 is a schematic configuration diagram, and FIG. 3 is a perspective view showing an oxide superconducting conductor to be cut and an oxide superconducting wire after cutting.

The oxide superconducting conductor 1 to be cut in the present invention has an intermediate layer 5, an oxide superconducting layer 6 and a stabilizing layer 7 on a metal tape-like substrate 3 as shown in FIG. The oxide superconducting conductor 1 is laminated and cut by a laser beam of a continuous wave laser as will be described later, so that a plurality of oxide superconducting conductors 1 having a width narrower than that of the oxide superconducting conductor 1 (FIG. 3) are obtained. In (b), four oxide superconducting wires 10 can be obtained.
Since this oxide superconducting wire 10 is formed by cutting the oxide superconducting conductor 1 in its width direction, the oxide superconducting wire 10 has exactly the same structure except for its narrow width. The intermediate layer 5a, the oxide superconducting layer 6a, and the stabilizing layer 7a are laminated on the tape-like base material 3a made of the product.

More specifically, the oxide superconducting wire 10 has an intermediate layer 5 composed of a diffusion prevention layer 11, a bed layer 12, an orientation layer 15 and a cap layer 16 laminated on the upper surface of the base material 3a, as shown in FIG. The oxide superconducting layer 6a and the stabilizing layer 7a are laminated thereon, but in FIG. 3, the intermediate layer 5 is drawn as one layer for the sake of simplicity. Note that the diffusion preventing layer 11, the bed layer 12, and the cap layer 16 are not essential and may be omitted in some cases.
The oxide superconducting wire 10 shown in FIG. 4 shows a state in which a thicker stabilizing layer 8 is laminated on the stabilizing layer 7a, and the entire circumference of the laminate composed of the oxide superconducting wire 10 and the stabilizing layer 8 is shown. An insulating layer 18 is formed by winding the resin tape 17 around the insulating tape 18.
The stabilization layer 8 is formed by pasting or plating after obtaining the superconducting wire 10 as shown in FIG. 3B by cutting with a laser beam.
As the structure shown in FIG. 4, the oxide superconducting wire 10 insulated with the insulating layer 18 can be coiled to be used for a superconducting coil or the like, and the oxide superconducting wire 10 insulated with the insulating layer 18 is used. It can be used for applications such as superconducting cables for power transmission.
Hereinafter, each element of the oxide superconducting wire 10 will be described.

  The base material 3 (3a) can be used as a base material for a normal superconducting wire, has only to be high strength, is in the form of a tape to make a long cable, and is made of a heat-resistant metal. Is preferred. For example, various high-strength, high-heat-resistant metal materials such as nickel alloys such as stainless steel and hastelloy, or ceramics disposed on these various metal materials, and the like can be given. 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 (3a), and silicon nitride (Si ₃ N ₄ ), aluminum oxide (Al ₂ O ₃ , also referred to as “alumina”). Alternatively, it is made of GZO (Gd ₂ Zr ₂ O ₇ ) or the like, and is formed by a film forming method such as a sputtering method, and the thickness thereof is, for example, 10 to 400 nm.
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.

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 cap layer 16 is epitaxially grown by being formed on the surface of the orientation layer 15 in which the in-plane crystal axes are oriented as described above, and then grows laterally, so that the crystal grains are self-oriented in the in-plane direction. may material, 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. The thickness of the CeO ₂ layer is preferably 100 nm or more in order to obtain sufficient orientation, but if it is too thick, the crystal orientation deteriorates, so it can be in the range of 50 to 5000 nm.

The oxide superconducting layer 6 (6a) may be a known one, and specifically, is a material made of REBa ₂ Cu ₃ O _y (RE represents a rare earth element such as Y, La, Nd, Sm, Er, Gd). The thing can be illustrated. 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.

The first stabilizing layer 7a laminated on the oxide superconducting layer 6 is formed as a layer made of a metal material having good conductivity, such as Ag, and a low contact resistance with the oxide superconducting layer 6, which is compatible. The In order to form the Ag stabilizing 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 second stabilization layer 8 is provided for stabilizing the oxide superconducting layer 6a, and is provided for bypassing the current to prevent the oxide superconducting layer 6a from transitioning to the normal conducting state. Therefore, it is formed from a highly conductive metal material such as Cu, Al, or an alloy thereof. When the oxide superconducting wire 10 is applied for the purpose of a current limiting device or the like, it is preferable to use a high resistance material as the stabilization layer 8, and thus a metal material having a high resistance to Cu, Ag, Al, such as NiCr It can consist of
The stabilization layer 8 is formed thicker than the stabilization layer 7 and has a thickness of about 100 to 300 μm in order to ensure a sufficient capacity as a current bypass path. In that case, it can be formed on the stabilization layer 7 by using a soldering or conductive adhesive bonding method or a plating method.

In this embodiment, before the thick stabilization layer 8 is provided, this is cut from the state of the oxide superconducting conductor 1 shown in FIG. 3A in which the Ag stabilizing layer 7 is formed on the oxide superconducting layer 6. Then, when the oxide superconducting wire 10 having a narrow width is manufactured, it is cut using a laser beam of a continuous wave laser.
FIG. 1 shows a schematic configuration of a cutting device 20 used for generating a continuous wave laser to cut the oxide superconductor 1, and the cutting device 20 of this example includes a plurality of (three in the example of FIG. 1). A light source 21 for excitation laser, a coupler 22 as a beam combiner for coupling excitation lasers from the plurality of light sources 21, and a double clad fiber connected to the coupler 22 for amplification. The fiber 23, a transmission fiber 24 connected to the amplification fiber 23, and an output unit 25 connected to the tip of the transmission fiber 24 are mainly configured.

  As an example, the amplifying fiber 23 may be a rare earth-doped fiber that is an optical amplifying medium. As a rare earth-doped fiber, a rare-earth element, for example, a core to which rare-earth elements such as Yb (ytterbium), Er (erbium), Tm (thulium), Nd (neodymium), Pr (praseodymium) are added, and the outer periphery of the core are surrounded. A rare earth-doped double clad fiber composed of a first clad and a second clad surrounding the first clad can be used.

The output unit 25 is connected to a cylindrical guide unit 26 for introducing a laser output from the transmission fiber 24, an optical device 27 accommodated on the upper side of the guide unit 26, and a lower side of the guide unit 26. The nozzle body 28 and the gas supply source 29 connected to the lower side of the nozzle body 28 are mainly configured.
The optical device 27 includes a plurality of optical lenses, and by adjusting the mutual position of these optical lenses, the diameter of the laser light incident from the transmission fiber 24 is reduced to the outside of the tip of the nozzle body 28. The laser beam can be focused and irradiated so as to obtain an appropriate beam diameter. A gas introduction part 30 is formed on the upper side wall of the nozzle body 28, and a gas supply source 29 such as an inert gas is connected to the gas introduction part 30. By sending a shielding gas such as an inert gas from the gas supply source 29 to the inside of the nozzle body 28, the shielding gas can be ejected from the opening at the tip of the nozzle body 28.

In order to cut the oxide superconductor 1 using the cutting device 20, the tip of the nozzle body 28 is positioned, for example, at the center of the oxide superconductor 1 installed horizontally as shown in FIG. The central portion of the object superconductor 1 is irradiated with a laser beam of a continuous wave laser, and the oxide superconductor 1 is moved in the length direction at a predetermined speed.
The multimode excitation light input from the excitation light emitting device 21 to the coupler 22 via the connection fiber 21 a in the cutting device 20 is optically coupled in the coupler 22 and input to the amplification fiber 23. The wavelength is amplified and the output is amplified at 1, converted into a single mode, and output as a continuous wave laser through the transmission fiber 24.
As an example of a continuous wave laser applied in the present embodiment, a continuous wave laser having a center wavelength of 1080 nm can be used, and the beam output side when a laser beam is focused and irradiated to the outside of the tip of the nozzle body 8 with a beam output of 300 W. The beam diameter can be about 10 μm to 100 μm, for example, 20 μm. The center wavelength of the continuous wave laser can be about 1050 to 1100 nm.

For the laser beam reaching the output unit 25 from the transmission fiber 24, the optical device 27 is adjusted to reduce the laser beam diameter of the continuous wave laser having a center wavelength of 1080 nm to about 20 μm, and is oxidized from the tip of the nozzle body 28 as described above. When the central portion of the object superconducting conductor 1 is irradiated, the stabilization layer 7, the oxide superconducting layer 6, the intermediate layer 5, and the base material 3 in the central portion of the oxide superconducting conductor 1 can be fused by a laser beam.
Further, since the laser beam is irradiated from the outside of the stabilization layer 7, the laser beam irradiation portion is sequentially formed in the order of the stabilization layer 7, the oxide superconducting layer 6, the intermediate layer 5, and the substrate 3 in the oxide superconductor 1. Although it can be melted sequentially, the shield gas ejected from the tip of the nozzle body 28 blows away the melted melt of the stabilized layer 7, oxide superconducting layer 6, intermediate layer 5, and substrate 3. Further, the shield gas ejected from the tip of the nozzle body 28 in a state where the laser beam penetrates the substrate 3 oxidizes the melted stabilization layer 7, oxide superconducting layer 6, intermediate layer 5, and substrate 3. The rear surface side of the object superconducting conductor 1 is also blown away and removed. By these actions, adhesion of molten dross caused by the melt of the stabilization layer 7, the oxide superconducting layer 6, the intermediate layer 5, and the base material 3 can be prevented in the portion melted by the laser beam. The irradiation angle of the laser beam to the oxide superconducting conductor 1 may be 90 °, but may be inclined by about 1 to 2 °. This is to prevent the return light from returning to the optical fibers 24 and 23 side because the light reflectance of the Ag stabilizing layer 7 is high.
From the melting start state by this laser beam, the oxide superconducting conductor 1 is moved in the length direction sequentially at a predetermined speed, for example, 150 mm / s, so that the oxide superconducting conductor 1 is centered over the entire length in the length direction. And can be divided into two oxide superconducting wires.
If the above operation is repeated a plurality of times at predetermined intervals in the width direction of the oxide superconductor 1, the oxide superconductor 1 can be divided into four as shown in FIG. . When the oxide superconducting conductor 1 is long, it takes time to scan the laser beam over its entire length, so four output units 25 are provided in parallel and four laser beams are provided. By adopting a configuration capable of simultaneous irradiation, the entire length of the oxide superconductor 1 may be divided into four by one laser beam scanning.

As described above, when the oxide superconductor 1 is melted by a continuous wave laser beam, the melted portion of the oxide superconductor 1 can be formed more smoothly than the conventional method using a pulse laser. FIG. 5 is a partial enlarged view showing an example of a plan view of a fused portion of the oxide superconducting wire 10 obtained by fusing with a laser beam of a continuous wave laser.
As described above, the melted portion of the oxide superconducting wire 10 has a large number of concave and convex portions 10c formed in the length direction of the oxide superconducting wire 10 (in the left-right direction in FIG. 5) in an enlarged plan view. In this way, when the beam diameter is set to 20 μm using a continuous wave laser beam and blown under the above-described conditions, the maximum height Rz of the uneven portion 10 c can be formed to 5 μm or less.

The laser beam of the pulse laser used in the prior art melts an object by repeatedly outputting a laser beam having a very high peak output alternately in a pulse shape. In the laser beam of this pulse laser, when the oxide superconductor 1 is melted, the maximum height Rz of the concavo-convex portion is larger than 10 μm. For example, when fusing with a YAG laser, the concavo-convex with a maximum height of 10-20 μm Generated.
In addition, the short wavelength laser lacks the output for fusing the oxide superconductor 1 and the oxide superconductor 1 cannot be melted itself. In addition, the CO ₂ laser having a long wavelength or the like does not emit light from the Ag stabilizing layer 7. Since the reflectivity is high, even if the CO ₂ laser is irradiated, the light reflection of the stabilization layer 7 increases and the oxide superconducting conductor 1 cannot be fused at high speed.
On the other hand, with the laser beam of the continuous wave laser used in the present embodiment, the melted surface can be processed more smoothly than the conventional technique so as to have an uneven portion with a maximum height of 5 μm or less.

  When the oxide superconducting conductor 1 is long, the oxide superconducting conductor 1 is wound around a reel or the like, and the oxide superconducting is performed by irradiating a laser beam while the reel is sequentially drawn out and wound around another reel. The conductor 1 is preferably divided into oxide superconducting wires 10 over its entire length.

"Example 1"
A tape-like base material having a width of 10 mm, a thickness of 0.1 mm, and a length of 100 m made of Hastelloy C276 (trade name of Haynes, USA) is prepared, and a thickness of 100 nm made of Al ₂ O ₃ is formed on the surface of the tape-like base material. Then, a 30 nm thick bed layer made of Y ₂ O ₃ was formed thereon by ion beam sputtering. 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 alignment layer of MgO having a thickness of 10 nm was formed on the bed layer by ion beam assisted vapor 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.

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.
Next, an Ag stabilizing base layer having a thickness of 10 μm was formed on the oxide superconducting layer by sputtering, and oxygen annealing was performed at 500 ° C. Through the above steps, an oxide superconducting conductor having a structure including a diffusion preventing layer, a bed layer, an alignment layer, a cap layer, an oxide superconducting layer, and a stabilizing layer was formed on a long tape-like substrate.

The oxide superconducting conductor is irradiated with a fiber laser beam of a continuous wave laser having a central wavelength of 1080 nm, using a cutting processing apparatus having a schematic configuration shown in FIG. 1, and an output of 300 W, a beam diameter of 20 μm, and a processing speed of 150 mm / s. A cutting process was performed to divide the oxide superconducting conductor having a width of 10 mm into two oxide superconducting wires. In the cutting process, nitrogen gas was blown from the tip of the nozzle body onto the upper surface of the oxide superconducting conductor so that the molten dross did not adhere to the cut surface. By this operation, an uneven portion having a maximum height Rz = 3 to 5 μm was generated on the cut surface of the Hastelloy tape base material, but a large uneven portion was not seen by naked eye observation, and the surface was smooth.
When the insulating superconducting wire with a width of 5 mm and a thickness of 12.5 μm was wound on the obtained oxide superconducting wire with a width of 12.5 μm with a tension of 150 g, the insulating tape could be wound without cutting. I was able to process it.
Further, an aluminum alloy pin member 37 having a disc portion 35 and a rod portion 36 having an outer diameter of 2.7 mm on the upper surface of the stabilization layer 7 of the oxide superconducting wire 10 cut and processed as shown in FIG. 6 is an epoxy resin adhesive. Then, a peel test was performed in which the rod portion 36 was pulled in a direction perpendicular to the oxide superconducting wire 10. When a similar peel test was performed on five samples of the oxide superconducting wire cut with the laser beam of the continuous wave laser, the average value of the peel force was about 30 kgf.

"Comparative Example 1"
An oxide superconductor having the same configuration as that of the oxide superconductor used in the examples was prepared. Using a YAG laser with a center wavelength of 355 nm, cutting was performed to divide the 10 mm-wide oxide superconductor into two under the conditions of a frequency of 30 KHz, an output of 2.4 W, a beam diameter of 20 nm, and a processing speed of 5 mm / s.
In the YAG laser, when the processing speed was increased from the above-mentioned value, the oxide superconducting conductor could not be cut. Alternatively, when the processing speed is increased from the above values, large uneven portions are generated on the cut surface of the base material of the oxide superconducting conductor. Therefore, cutting is performed so that the uneven portions are not generated by setting the above processing speed, and oxidation is performed. A superconducting wire was obtained. In the cutting with the YAG laser, the cutting was performed while blowing nitrogen gas on the upper surface of the oxide superconducting conductor. Note that, on the cut surface by the YAG laser, an uneven portion having a maximum height Rz of 10 to 20 μm was generated on the cut surface even at the above processing speed.
When a resin tape equivalent to that used in the examples was wound around the oxide superconducting wire with the same tension, a part of the resin tape was cut.
A peel test using the pin member 37 was performed on the obtained oxide superconducting wire under the same conditions as in the example. When a similar peel test was performed on five oxide superconducting wire samples obtained by cutting with the YAG laser, the average value of the peel force was about 28 kgf.
In the sample of Comparative Example 1, the resin tape was partially cut, but could be wound. In addition, since the processing speed at the time of producing the sample of this comparative example 1 is 5 mm / s and it is very slow, it is slow and unsuitable for processing a long superconductor like an oxide superconductor. .

"Comparative Example 2"
Of the cutting conditions using the YAG laser used in Comparative Example 1, the cutting process test was performed in which only the processing speed was changed to 10 mm / s and the oxide superconductor having a width of 10 mm was divided into two.
As a result, a large sharp concavo-convex portion exceeding Rz: 20 μm was generated on the cut surface of the oxide superconductor. When the resin tape was wound around the oxide superconducting conductor having this cut surface under the same conditions as in Comparative Example 1, a phenomenon that the resin tape was cut during the winding occurred. When the cutting position of this resin tape was examined, a cut portion was generated along the uneven portion of the cut surface of the base edge, so that the resin tape pressed against the uneven portion by the winding tension was sharp and large uneven portions. It seems to have been cut.
As described above, when cutting the oxide superconductor using the YAG laser, if the processing speed is increased, a large uneven portion is generated on the cut surface, and the wound resin tape is cut, so that the long oxide superconductor is cut. It has been found that when cutting the film, it cannot be cut at a speed that allows efficient cutting.

“Comparative Example 3”
An oxide superconductor having the same configuration as that of the oxide superconductor used in the examples was prepared. Using a fiber laser having a center wavelength of 1080 nm, cutting was performed to divide the oxide superconductor having a width of 10 mm into two under the conditions of a frequency of 60 KHz, an output of 30 W, a beam diameter of 20 nm, and a processing speed of 10 mm / s.
In the fiber laser (pulse output) under this condition, when the processing speed was increased from the above-mentioned value, a portion that could not be cut into the oxide superconductor was generated. Alternatively, when the processing speed is increased from the above values, large uneven portions are generated on the cut surface of the base material of the oxide superconducting conductor. Therefore, cutting is performed so that the uneven portions are not generated by setting the above processing speed, and oxidation is performed. A superconducting wire was obtained. In this fiber laser cutting, cutting was performed while blowing nitrogen gas on the upper surface of the oxide superconducting conductor. In the cut surface by this fiber laser, even at the above-described processing speed, an uneven portion having a maximum height Rz of 10 to 20 μm was generated on the cut surface.
When a resin tape equivalent to that used in the examples was wound around the oxide superconducting wire with the same tension, the resin tape was partially cut.
When a similar peel test was performed on five oxide superconducting wire samples obtained by cutting with the fiber laser, the average peel force was about 29 kgf.
When the cutting speed was set to 20 m / s using a fiber laser with a pulse output, the Rz of the concavo-convex part generated on the cut surface increased to 20 to 30 μm. This is presumably because the overlap of the pulse waves applied to the cut portion of the oxide superconductor becomes worse as the cutting speed increases.

“Comparative Example 4”
An oxide superconductor having the same configuration as that of the oxide superconductor used in the examples was prepared. The oxide superconducting conductor was mechanically divided into two parts by a cutting blade, but a defect portion where the Ag stabilizing layer was peeled off at two points during the cutting process was generated.
When a similar peeling test was performed on five oxide superconducting wire samples obtained by cutting with the cutting blade, the average value of the peeling force was about 3 Kgf.

  The present invention can be used for oxide superconducting wires used in various superconducting devices such as superconducting coils, superconducting cables for power transmission, superconducting motors, and current limiters.

  DESCRIPTION OF SYMBOLS 1 ... Oxide superconductor, 3, 3a ... Base material, 5, 5a ... Intermediate layer, 6, 6a ... Oxide superconductor layer, 7, 7a ... Stabilization layer, 8 ... Stabilization layer, 10 ... Oxide superconducting wire DESCRIPTION OF SYMBOLS 11 ... Diffusion prevention layer, 12 ... Bed layer, 15 ... Orientation layer, 16 ... Cap layer, 17 ... Insulating tape, 18 ... Insulating layer, 20 ... Cutting device, 21 ... Light emitting device of excitation laser, 22 ... Coupler , 23 ... Amplifying fiber, 24 ... Transmission fiber, 25 ... Output unit, 27 ... Optical system, 28 ... Nozzle body, 29 ... Gas supply source.

Claims (4)

A tape-shaped base material, an intermediate layer provided on the base material, an oxide superconducting layer provided on the intermediate layer, and a stabilization layer provided on the oxide superconducting layer The irradiated oxide superconductor is irradiated with a laser beam from the outside on the stabilization layer forming side along the length direction of the substrate to melt the stabilization layer, the oxide superconducting layer, the intermediate layer, and the substrate. it makes the case where the oxide superconductor is divided into a plurality in the width direction to produce an oxide superconducting wire, a laser beam of a continuous wave laser used as the laser beam, the substrate with a laser beam of the continuous-wave laser The concave and convex portions formed on the molten cross-section of the metal are set to 5 μm or less at the maximum height Rz, and the laser beam is produced by the shielding gas ejected to the oxide superconducting conductor with the laser beam irradiation. Wherein the stabilizing layer is melted, the oxide superconducting layer, said intermediate layer and a method of manufacturing an oxide superconducting wire which is characterized that you remove blowing a melt of the substrate. The oxide according to claim 1, further comprising a step of winding an insulating tape so as to surround the laminate of the base material, the intermediate layer, the oxide superconducting layer, and the stabilization layer after the continuous wave laser is melted by a laser beam. Manufacturing method of superconducting wire.   A tape-shaped base material, an intermediate layer provided on the base material, an oxide superconducting layer provided on the intermediate layer, and a stabilization layer provided on the oxide superconducting layer The oxide superconducting conductor is formed by fusing a plurality of oxide superconducting conductors with a laser beam in the width direction thereof, and is formed on a fusing portion by a laser beam formed along the length direction of the base material. An oxide superconducting wire characterized in that the maximum height Rz of the formed uneven portion is 5 μm or less. The oxide superconducting wire according to claim 3 , wherein an insulating tape is wound so as to surround the periphery of the laminate including the base material, the intermediate layer, the oxide superconducting layer, and the stabilizing layer.

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