JP2013025892A - Manufacturing method of tape-like oxide superconductive wire material and heat treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tape-like oxide superconductive wire material having uniform in a longitudinal direction and excellent superconducting properties inside a furnace core tube.SOLUTION: In a heat treatment apparatus 10, a truncated conical rotor 12 is disposed rotatably around the furnace core axis C inside the cylindrical heat treatment space 11a of a furnace core tube 11. In the rotor 12, the surface 12a on which plural through holes 17 are formed is a conical peripheral surface the diameter of which decreases from one end connected with a gas exhaust pipe 14 toward the other end. A tape-like wire material 50 on which the film body of a superconducting precursor is formed is wound on the conical peripheral surface, and the atmosphere gas is supplied from a position facing the film surface of the tape-like wire material 50 while spaced apart therefrom.

Description

  TECHNICAL FIELD The present invention relates to a method for manufacturing a tape-shaped oxide superconducting wire and a heat treatment apparatus, and more particularly to superconductivity using a metal-organic deposition (MOD) method on a metal substrate on which an intermediate layer is formed. The present invention relates to a technique for forming a layer.

Conventionally, as a method for producing a YBa ₂ Cu ₃ O _7-X (YBCO) -based tape-shaped oxide superconducting wire, a superconducting layer can be formed on a metal substrate on which an intermediate layer is formed using a MOD method. Known (see Patent Documents 1, 2, and 3).

  In this MOD method, first, a tape-like base material on which an oxide intermediate layer is formed is octyl such as trifluoroacetate (TFA salt) containing each metal element constituting a superconductor in a predetermined molar ratio. It is immersed in a superconducting raw material solution which is a mixed solution of metal organic acid salts such as acid salts and naphthenates. Next, the mixed solution is applied to the surface of the substrate by pulling up the substrate from the superconducting raw material solution (so-called dip coating method). Next, an oxide superconducting layer is formed by performing preliminary firing and main firing.

  Since the MOD method can continuously form an oxide superconducting layer on a long substrate even in a non-vacuum state, the process is more effective than a gas phase method such as a PLD (Pulse Laser Deposition) method or a CVD (Chemical Vapor Deposition) method. It is attracting attention because it is simple and can be reduced in cost.

  Patent Documents 1 and 2 disclose a batch-type heat treatment apparatus that heat-treats a substrate having a superconducting raw material solution attached to the surface thereof. Compared with the reel-to-reel heat treatment apparatus as shown in Patent Document 3, the batch-type heat treatment apparatus has an advantage that a stable superconducting layer can be formed because the atmosphere in the furnace is easily controlled. In addition, the batch-type heat treatment apparatus has an advantage that the firing can be completed in a short time with a small-sized apparatus, compared with the reel-to-reel type heat treatment apparatus. Incidentally, the heat treatment equipment of the reel-to-reel method performs firing by installing a wire feeding mechanism and a winding mechanism at both ends of a tunnel-shaped furnace core tube, and moving the wire at a constant speed in the furnace. is there.

  The configuration of the heat treatment apparatus disclosed in Patent Documents 1 and 2 will be briefly described. As shown in FIG. 1, the heat treatment apparatus 1 includes a heat treatment furnace 4 including a furnace body 2 and an electric heater 3 disposed outside the furnace body 2, and a drum-shaped rotation disposed in the heat treatment furnace 4. And a body 5. A base material 6 to which a superconducting material is attached is wound around a cylindrical surface of the rotating body 5. The rotating body 5 around which the substrate 6 is wound is rotationally driven by a rotational drive mechanism. A large number of through holes are formed in the rotating body 5. Further, one end side of the rotating body 5 is closed by a lid body to which a gas discharge pipe 7 for discharging the gas inside the rotating body to the outside of the heat treatment furnace 4 is connected, and the other end side is sealed by the lid body 5a. Has been. The base material 6 is heated by the heater 8 provided in the surface direction of the base material 6 in the state wound around the rotating body 5. In addition, an atmospheric gas composed of an inert gas, oxygen gas, and water vapor is ejected from the surface direction of the base material 6 toward the base material 6, and this atmospheric gas is discharged as a gas after reaction (exhaust gas). It is discharged through the pipe 7.

Japanese Patent No. 4468901 JP 2009-48817 A Japanese Patent No. 44011992

  A superconducting precursor obtained by pre-calcining a base material coated with a mixed solution containing trifluoroacetate using the heat treatment apparatus disclosed in Patent Documents 1 and 2, and a precursor containing fluorine (F) In the method (TFA-MOD method) for forming a YBCO film by subjecting this to a film on the intermediate layer and then subjecting it to firing, as the atmospheric gas (reactive gas) supplied to the precursor film during the firing Use water vapor.

The YBCO production reaction formula at this time is
1 / 2Y ₂ Cu ₂ O ₅ + 2BaF ₂ + 2CuO + 2H ₂ O → YBCO + 4HF
It becomes.

  Thus, during the main firing, since the precursor film is heat-treated using water vapor as an atmospheric gas, HF is generated, and hydrogen fluoride (HF) gas is generated as a post-reaction gas after this reaction. .

In the TFA-MOD method, the fluorine removal rate when decomposing the fluorine compound (BaF ₂ ) is the reaction rate-limiting factor for YBCO formation. Therefore, there is a problem that the superconducting characteristics of the fired YBCO film are deteriorated due to the influence of hydrogen fluoride (HF) gas (exhaust gas) generated after the reaction.

  In particular, in order to obtain a long tape-shaped oxide superconducting wire having a critical current density (Jc) of 2.0 or more and a critical current value (Ic) of 300 A or more, the superconducting layer is 1.5 μm or more. It is necessary to form a film with a film thickness. When the film thickness is set to the above, complete removal of hydrogen fluoride (HF) gas becomes more difficult, and the above characteristics cannot be obtained.

  For this reason, in order to improve the superconducting characteristics of the YBCO film, it is important how to remove fluorine contained in the precursor in the main firing.

  However, in the heat treatment apparatus 1 shown in FIG. 1, the rotating body 5 is long in the axial direction. For this reason, as shown in FIG. 2, when exhausting the hydrogen fluoride gas, which is a gas after reaction, from at least one end of the both sides of the rotating body 5 through the gas exhaust pipe 7, the gas exhaust pipe 7 side There is a possibility that a difference in the exhaust amount of hydrogen fluoride gas (indicated by arrows A and B) may occur between the one end of the gas outlet and the other end on the side away from the gas discharge pipe 7. In FIG. 2, exhaust is performed by suction from one end side.

  As described above, when a difference occurs in the exhaust amount in the vicinity of both ends of the rotator 5, the base material wound around the rotator 5 has different fluorine removal speeds in the portions located near both ends of the rotator 5. It will be. As a result, an oxide superconducting wire having uniform superconducting characteristics in the length direction cannot be obtained.

  This invention is made in view of this point, and provides the manufacturing method and heat processing apparatus of a tape-form oxide superconducting wire which can manufacture the tape-form oxide superconducting wire which has the superconducting characteristic which is uniform and excellent in the length direction. For the purpose.

  One aspect of the method for producing a tape-shaped oxide superconducting wire of the present invention is a furnace core tube having a cylindrical heat treatment space, and is rotatable around the furnace core axis of the furnace core tube inside the heat treatment space. And a cylindrical rotating body in which a tape-shaped wire having a superconducting precursor film formed thereon is wound on a surface on which a large number of through holes are formed, and the rotation in the furnace core tube A gas supply pipe for supplying an atmospheric gas to the film surface of the film body in the tape-shaped wire wound around the surface and disposed opposite the surface of the body, and reacted with the film body In the method of manufacturing an oxide superconducting wire using a heat treatment apparatus including a gas discharge pipe for discharging a subsequent gas from the inside of the rotating body to the outside of the furnace core tube, the surface of the rotating body is the furnace A conical circumferential surface having a diameter reduced in the direction of the core axis; The precursor of the membrane body is tape-shaped wire is formed by winding, and to supply the atmospheric gas in the longitudinal direction of the rotating body.

  One aspect of the heat treatment apparatus of the present invention includes a furnace core tube provided with a cylindrical heat treatment space, and is disposed in the heat treatment space so as to be rotatable with respect to the furnace core axis of the furnace core tube, and many A cylindrical rotating body on which a tape-like wire having a superconducting precursor film formed thereon is wound on the surface on which the through-hole is formed, and in the furnace core tube, facing the surface of the rotating body A gas supply pipe for supplying atmospheric gas to the film surface of the film body in the tape-shaped wire rod disposed and wound on the surface; and a gas after reacting with the film body in the rotating body A gas discharge pipe for discharging from the inside to the outside of the furnace core pipe, wherein the gas discharge pipe is provided at least at one end of both ends of the rotating body. The inside is connected to the inside of the rotating body, and the surface of the rotating body is connected to the furnace. A configuration having a conical peripheral surface reduced in diameter in the axial direction.

  According to the present invention, it is possible to produce a tape-shaped oxide superconducting wire that is uniform in the length direction and has excellent superconducting properties.

Schematic cross-sectional view showing the main components of a conventional batch heat treatment apparatus The figure which shows typically the gas displacement in the rotary body of the heat processing apparatus BRIEF DESCRIPTION OF THE DRAWINGS Schematic sectional drawing which shows the principal part structure of the heat processing apparatus of the tape-shaped oxide superconducting wire which concerns on one embodiment of this invention XX sectional drawing of FIG. 3 which shows the principal part structure of the heat processing apparatus Schematic showing the rotating body of the heat treatment equipment Schematic sectional view showing the gas supply pipe of the heat treatment apparatus The figure which shows typically the gas displacement in the rotary body of the heat processing apparatus Schematic showing the manufacturing method of YBCO superconducting wire by MOD method Sectional drawing which shows the structure of the tape-form oxide superconducting wire produced | generated by the MOD method using the heat processing apparatus which concerns on one embodiment of this invention The schematic diagram which shows the modification of the rotary body of the heat processing apparatus which concerns on one embodiment of this invention

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<Outline of MOD Method Using Heat Treatment Apparatus According to this Embodiment>
FIG. 8 shows an outline of a method for producing a tape-shaped oxide superconducting wire (YBCO superconducting wire) having a YBCO superconducting layer by the MOD method.

First, a Gd ₂ Zr ₂ O ₇ intermediate layer is formed as a template by a IBAD method on a tape-shaped Ni alloy substrate (base material), and further a CeO ₂ intermediate layer is formed thereon by a sputtering method. A composite substrate is formed. On this composite substrate, Y: TFA salt (trifluoroacetate salt), Ba-TFA salt and Cu-naphthenic acid salt were added in an organic solvent in the coating step (a). Y: Ba: Cu = 1: 1.5: A mixed solution (superconducting raw material solution) 30 dissolved at a ratio of 3 is applied by a dip coating method. After the mixed solution 30 is applied, it is temporarily fired in the temporary firing step (b). This coating step (a) and pre-baking step (b) are repeated a predetermined number of times to form a film body as a superconducting precursor on the intermediate layer of the composite substrate. In FIG. 8, a wire rod in a state where a film body as a superconducting precursor is formed on the composite substrate is indicated by a wire rod 49. Thereafter, in the main firing step (c), in the tape-like wire 50 in which the film body as the superconducting precursor is formed on the intermediate layer of the composite substrate, the crystallization heat treatment of the film body of the superconducting precursor, that is, YBCO superconductivity. Heat treatment for body production is performed. Next, an Ag stabilizing layer is applied to the produced YBCO superconductor in the step (d) by a sputtering method, and then a post-heat treatment is applied in the step (e) to form a tape-like YBCO superconducting wire (oxide superconducting wire). ) 60 is manufactured.

  The heat treatment apparatus of the embodiment according to the present invention is used for the crystallization heat treatment in the step (c), and heat-treats the superconductor precursor in the tape-shaped wire 50 to generate a YBCO superconductor. Note that the heat treatment apparatus may also be applied to the formation of the intermediate layer.

  The Ni alloy substrate may have a biaxial orientation or may have a biaxial orientation intermediate layer formed on a non-oriented metal substrate. Further, the intermediate layer is formed of one layer or a plurality of layers. As an application method, it is possible to use an inkjet method, a spray method, etc. in addition to the dip coating method described above, but basically, this example is applicable as long as it is a process capable of continuously applying a mixed solution onto a composite substrate. Not constrained by. The film thickness to be applied at one time is 0.01 μm to 2.0 μm, preferably 0.1 μm to 1.0 μm.

  The superconducting raw material solution used here is a mixed solution in which a metal organic acid salt or an organic metal compound containing Y, Ba, and Cu in a predetermined molar ratio is dissolved in an organic solvent. When the number of moles is Y: Ba: Cu = 1: a: 3, a raw material solution having a Ba molar ratio in the range of a <2 is used. In this case, in order to obtain high Jc and Ic values, the Ba molar ratio in the raw material solution is preferably in the range of 1.0 ≦ a ≦ 1.8, and more preferably the Ba molar ratio in the raw material solution. Is in the range of 1.3 ≦ a ≦ 1.7. Thereby, the segregation of Ba can be suppressed, and as a result, the precipitation of Ba-based impurities at the grain boundaries is suppressed. Therefore, generation of cracks is suppressed and electrical connectivity between crystal grains is improved. By forming a superconducting film by the MOD method, a tape-like oxide having a high-speed uniform thick film and excellent superconducting characteristics. Superconducting wire 60 can be easily manufactured. In addition, examples of the metal organic acid salt include octyl acid salt, naphthenic acid salt, neodecanoic acid salt, and trifluoroacetic acid salt of each element, but one or more kinds of the salts are uniformly dissolved in an organic solvent, Any material that can be applied on the composite substrate can be used.

<Oxide superconducting wire>
FIG. 9 is a cross-sectional view schematically showing a tape-shaped oxide superconducting wire produced by the MOD method using the heat treatment apparatus of the present embodiment.

  The oxide superconducting wire 60 shown in FIG. 9 has a tape shape, and an intermediate layer 52, a tape-shaped oxide superconducting layer (hereinafter referred to as “superconducting layer”) 53, and stabilization on a tape-like metal substrate 51. The layer 54 is formed by sequentially stacking layers. Here, the intermediate layer 52 includes a first intermediate layer 52a and a second intermediate layer 52b.

  The tape-shaped metal substrate 51 is, for example, nickel (Ni), nickel alloy, stainless steel, or silver (Ag). Here, the metal substrate 51 is a crystal grain non-oriented, heat-resistant, high-strength metal substrate, and is Ni-Cr-based (specifically, Ni-Cr-Fe-Mo-based Hastelloy (registered trademark) B, C, X). Etc.), W-Mo series, Fe-Cr series (for example, austenitic stainless steel), Fe-Ni series (for example, non-magnetic composition type) and other materials such as cubic Vickers hardness (Hv ) = 150 or more nonmagnetic alloy. The thickness of the metal substrate 51 is, for example, 0.1 mm or less.

The first intermediate layer 52a is a layer made of MgO formed on the tape-shaped metal substrate 51 by the IBAD method. On the first intermediate layer 52a, a second intermediate layer 52b, which is an omniaxially oriented layer in which CeO ₂ is vapor-deposited by a sputtering method (which may be PLD), is formed. The first and second intermediate layers 52a and 52b have a thickness of about 1000 nm. When the second intermediate layer 52b is a Ce—Gd—O film in which Gd is added to a CeO ₂ film, in order to obtain good orientation when a YBCO superconducting layer is formed as the superconducting layer 53, The amount of Gd added is preferably 50 at% or less. A superconducting layer 53 is formed on the second intermediate layer 52b. In the superconducting wire 60, the intermediate layer 52 is formed by the first intermediate layer 52a and the second intermediate layer 52b. An intermediate layer 52 is formed on these metal substrates 51 to constitute a composite substrate. Note that the composite substrate may be one having biaxial orientation, or one in which an intermediate layer 52 having biaxial orientation is formed on a metal substrate 51 having no orientation. Further, the intermediate layer 52 may be formed of one layer or may be formed of three or more layers.

  On the superconducting layer 53, there is provided a stabilizing layer 54 which is a noble metal such as silver, gold or platinum, or an alloy thereof and is a low resistance metal. The stabilization layer 54 is formed immediately above the superconducting layer 53 to prevent the superconducting layer 53 from deteriorating in performance caused by reaction due to direct contact with materials other than precious metals such as gold and silver, or alloys thereof. To do. In addition to this, the stabilization layer 54 disperses heat generated by an accident current or alternating current to prevent destruction and performance degradation due to heat generation. The thickness of the stabilization layer 54 is 10-30 micrometers here.

The superconducting layer 53 is an all-axis oriented REBCO layer, that is, a REBa _y Cu ₃ O _z system (RE represents one or more elements selected from Y, Nd, Sm, Eu, Gd, and Ho, and y ≦ 2 And z = 6.2 to 7.). Here, the superconducting layer 53 is an yttrium-based oxide superconductor (RE123).

  The superconducting raw material solution applied on the intermediate layer 52 to be the superconducting layer 53 is RE (RE represents one or more elements selected from Y, Nd, Sm, Eu, Gd and Ho), Ba And an organometallic complex solution containing Cu and an organometallic complex solution (mixed solution).

  By using these organometallic complex solutions, the molar ratio y of Ba contained in the superconducting raw material solution can be produced within the range of y <2.

In addition, as a superconducting raw material solution, it is preferable to use the following solutions (a) to (d).
(A) Organometallic complex solution containing RE: a solution containing one or more of trifluoroacetate, naphthenate, octylate, levulinate, neodecanoate, and acetate containing RE, particularly RE A trifluoroacetate solution containing is desirable.
(B) Organometallic complex solution containing Ba: trifluoroacetate solution containing Ba (c) Organometallic complex solution containing Cu: Naphthenate, octylate, levulinate, neodecanoate containing Cu, A solution containing any one or more of acetates (d) An organometallic complex solution containing a metal having a high affinity with Ba: at least one metal selected from Zr, Sn, Ce, Ti, Hf, and Nb A solution containing any one or more of trifluoroacetate, naphthenate, octylate, levulinate, neodecanoate and acetate

  Further, it is desirable that the superconducting layer 53 is subjected to a calcination heat treatment in a temperature range of 400 to 500 ° C. in an atmosphere having a water vapor partial pressure of 3 to 76 Torr and an oxygen partial pressure of 300 to 760 Torr on the second intermediate layer 52b. Further, the superconducting layer 53 is preferably subjected to an intermediate firing heat treatment in a temperature range of 400 to 700 ° C. in an atmosphere having a water vapor partial pressure of 30 to 600 Torr and an oxygen partial pressure of 0.05 to 1 Torr. Further, the superconducting layer 53 is preferably subjected to a main firing heat treatment in a temperature range of 700 to 800 ° C. in an atmosphere having a water vapor partial pressure of 30 to 600 Torr and an oxygen partial pressure of 0.05 to 1 Torr.

<Configuration of heat treatment equipment>
The heat treatment apparatus 10 shown in FIG. 3 performs firing of a raw material solution (superconducting raw material solution) applied as a superconducting precursor film body in a tape-shaped wire 50 in a batch type. The heat treatment apparatus 10 includes a furnace core tube 11 having a cylindrical heat treatment space 11 a, a hollow truncated cone-shaped rotating body 12, a gas supply pipe 13, and a gas discharge pipe 14.

  The furnace core tube 11 is formed in a hollow cylindrical shape. The furnace core tube 11 includes a cylindrical furnace core main body (tubular main body) 11b and furnace core flanges 11c and 11d that respectively close openings at both ends of the furnace core main body 11b. The furnace core flange portions 11 c and 11 d constitute both end faces of the furnace core tube 11.

  The heat treatment space 11a of the furnace core tube 11 is defined by a furnace core main body part 11b and furnace core flange parts 11c and 11d. The heat treatment space 11a of the furnace core tube 11 is configured so that a reduced-pressure atmosphere or vacuum in the furnace can be maintained. In the furnace core tube 11, a heater 15 is disposed along the inner peripheral surface, and the inside of the heat treatment space 11 a is heated by the heater 15.

  Inside the furnace core tube 11, a truncated cone-shaped rotating body 12 is rotatably arranged around a furnace core axis C that is an axis of the furnace core tube 11. The rotating body 12 has a truncated cone-shaped rotating body main body 12b around which a tape-shaped wire 50 on which a precursor is formed is wound on the surface 12a.

  As described above, the tape-like wire 50 is coated with the mixed solution (mixed solution 30 in FIG. 8A) and calcined to form a precursor of the YBCO superconducting product on the substrate. It has been done. The tape-shaped wire 50 is spirally wound around the surface 12a of the rotating body 12b (the surface of the rotating body 12) with the film surface of the precursor exposed.

  As shown in FIGS. 3 and 5, a large number of through holes 17 are formed in the rotating body main body 12 b of the rotating body 12. The diameter of the through hole 17 is preferably equal to the tape width of the tape-shaped wire 50. Moreover, the hole area ratio is 50 to 95%, and the hole area ratio in the range of 89 to 91% is particularly preferable. The rotating body 12 is rotated at a constant speed during the heat treatment by a rotating mechanism (not shown). The rotating body 12 is made of a material that is resistant to high temperatures and hardly oxidizes, such as ceramics such as quartz glass and alumina, or metals such as Hastelloy and Inconel.

  The rotating body 12b is a truncated cone-shaped cylinder. The surface of the rotator main body 12b is inclined so as to gradually approach from the one end to the other end with respect to the axis of the rotator main body 12b, that is, the furnace core axis C. That is, the surface 12a of the rotator main body 12b is a conical circumferential surface that decreases in diameter from one end to which the gas discharge pipe 14 is connected toward the other end.

  One end of the rotating body main body 12b that is separated in the core axis direction is closed by a lid 12c. A gas discharge pipe 14 for discharging the atmospheric gas inside the rotating body main body 12b to the outside of the furnace core pipe 11 is inserted into the lid body 12c. The other end side of the rotating body main body 12b is closed by a lid body 12d.

  In this rotating body 12, the outer diameter of the lid body 12c that closes the opening through which the gas discharge pipe 14 is inserted is larger than the outer diameter of the lid body 12d. That is, the outer diameter of the rotating body 12b is formed so as to gradually decrease from the discharge side through the gas discharge pipe 14 as the distance from the discharge side increases. That is, the surface of the rotating body 12 is reduced in diameter from the discharge side (one end side) to which the gas discharge pipe 14 is connected toward the other end side.

  As a result, the distance from the inside of the gas discharge pipe 14 forming the gas discharge flow path to the surface 12a of the rotating body main body 12b is the distance between the both ends of the surface 12a and the end R close to the gas discharge pipe 14. The distance from the end Q away from the gas discharge pipe 14 is longer. For example, the distance from the furnace core axis C located at the center of the gas discharge channel to the surface 12a of the rotating body main body 12b that is vertically separated is closer to the end R than to the end Q. long. Here, as shown in FIGS. 5 and 7, the angle x formed between the generatrix l of the conical circumferential surface passing through one end of the rotating body 12 and the virtual line n parallel to the furnace core axis C passing through the one end is 0 degrees <x ≦ 10 degrees. More preferably, 0 degree <x ≦ 5 degrees. Here, the rotating body 12 is formed with x = 5 degrees.

  As shown in FIGS. 3 and 4, a plurality of gas supply pipes 13 are arranged in the furnace core tube 11 so as to be separated from the surface 12 a of the rotating body main body 12 b. The plurality of gas supply pipes 13 are arranged in parallel to the furnace core axis C and are arranged symmetrically in a cross section perpendicular to the furnace core axis C. Here, four gas supply pipes 13 are arranged in the furnace core tube 11 symmetrically with respect to the furnace core axis C and parallel to each other. That is, in the furnace core tube 11, the plurality of gas intake pipes 13 are arranged at a pitch of 90 ° in the circumferential direction around the furnace core axis C.

  Each gas supply pipe 13 includes a large number of gas ejection holes 20 that eject atmospheric gas to the rotator 12.

  As shown in FIG. 4, the gas ejection holes 20 in the gas supply pipe 13 are uniformly formed in the main body portion of the gas supply pipe 13 at regular intervals along the longitudinal direction. Each gas ejection hole 20 is a circular hole and ejects atmospheric gas uniformly. In order to uniformly eject the atmospheric gas and further remove the hydrogen fluoride gas, the flow rate when the atmospheric gas is supplied, specifically, on the film surface of the film body wound around the rotating body 12 The contact flow rate is preferably 200 m / s or more and 500 m / s or less. If it is less than 200 m / s, not only the atmosphere gas cannot be uniformly supplied to the superconducting precursor, but also the exhaust gas (HF gas) staying on the surface of the film body cannot be removed. Therefore, desired superconducting characteristics cannot be obtained. On the other hand, if it exceeds 500 m / s, the atmospheric gas can be uniformly ejected, but the crystallization reaction proceeds rapidly, so that it is difficult to control the epitaxial growth rate. Therefore, desired superconducting characteristics cannot be obtained.

  As shown in FIGS. 3 to 5, each gas supply pipe 13 is configured so that the atmosphere gas is supplied to the surface 12 a of the rotating body main body 12 b from a direction perpendicular to the furnace core axis C. Arranged along the longitudinal direction. The gas ejection holes 20 in the gas supply pipe 13 are arranged so as to be located at positions spaced upward from the surface 12a of the rotating body main body 12b.

  The gas supply pipe 13 is provided in the furnace core pipe 11 such that the distance between the gas ejection hole 20 and the most distant portion on the surface 12a of the rotating body 12 is in the range of 10 mm to 150 mm. A preferable range of the distance is 50 mm to 100 mm. Within the above range, the atmospheric gas can be uniformly ejected to the superconducting precursor, so that the hydrogen fluoride gas that is the gas after the reaction can be further removed. If it is less than the above range, the atmosphere gas ejected only to a part of the film surface of the film body of the tape-shaped wire 50 wound around the rotating body 12 does not come into contact with the superconducting wire in the longitudinal direction. Superconducting properties cannot be obtained. When the above range is exceeded, not only the gas flow rate increases and the production cost improves, but also the crystallization reaction proceeds rapidly, making it difficult to control the epitaxial growth rate. Therefore, desired superconducting characteristics cannot be obtained.

  The gas supply pipe 13 ejects atmospheric gas from the gas ejection hole 20 in the direction indicated by the arrow D in each figure.

  As a result, the gas supply pipe 13 causes the atmospheric gas to flow into the furnace core C from a position spaced upward from the film surface of the precursor in the tape-shaped wire 50 wound around the surface 12a of the rotating body 12b. Supply in a direction perpendicular to the direction. The diameter of the gas ejection hole 20 needs to be designed so that the gas pressure and the gas flow rate are uniform.

  The atmospheric gas is supplied from an atmospheric gas supply device (not shown) disposed outside the furnace core tube 11 via a connection tube (not shown) connected to the gas supply pipe 13. Incidentally, the gas supply device generates an atmospheric gas composed of an inert gas, oxygen gas, water vapor, or the like, and the atmospheric gas is ejected from the gas supply pipe 13.

  Further, the length of the gas supply pipe 13 is preferably longer than the length of the rotating body 12. That is, the length between the gas ejection holes 20 located at both ends of the gas supply pipe 13 is longer than the length of the rotating body 12. This makes it possible to cause a uniform reaction over the entire length of the tape-shaped wire 50 wound around the cylindrical rotating body 12.

  The gas discharge pipe 14 is continuous with the internal space of the rotating body main body 12b and is connected to the other end side of the rotating body main body 12b. Specifically, the gas discharge pipe 14 is formed with a plurality of holes in a portion inserted into the rotary body main body 12b, and the gas discharge pipe 14 and the rotary body main body 12b are in communication with each other. Yes. Further, one end of the gas exhaust pipe 14 is led out of the furnace core tube 11 through the lid body 12d from the inside of the rotating body main body 12b. The gas exhaust pipe 14 exhausts the atmospheric gas inside the rotating body to the outside of the furnace core pipe. Here, the gas discharge pipe 14 is formed on the rotating shaft (corresponding to the furnace core shaft C) of the rotating body main body 12b. Here, the exhaust gas in the rotating body 12b is sucked by an external device (not shown) through the gas discharge pipe 14.

  The gas supply pipe 13 and the gas discharge pipe 14 are made of a material that is resistant to high temperatures and hardly oxidizes, such as quartz glass, ceramics such as alumina, or metals such as Hastelloy and Inconel.

  In the heat treatment apparatus 10 described above, the cylindrical rotating body 12 around which the tape-like wire 50 is wound is rotated at a constant speed. In addition, the atmosphere gas supplied from a gas supply device (not shown) enters the heat treatment space 11 a held in the heating atmosphere by the heater 15 through the numerous gas ejection holes 20 of the gas supply pipe 13 to the tape. It is sprayed evenly against the film surface of the wire rod 50. The sprayed ambient gas reacts with the film surface and then enters the inside of the rotating body 12b through the numerous through holes 17 of the rotating body 12b in the rotating body 12. The gas after reaction inside the rotator main body 12b is discharged out of the furnace via the gas discharge pipe 14 connected on the other end side of the rotator main body 12b.

  Thus, in the heat treatment apparatus 10, the tape-like wire 50 on which the film body of the superconducting precursor is formed is a surface that is a conical circumferential surface whose diameter decreases from one end to which the gas exhaust pipe 14 is connected toward the other end. 12b is wound spirally. The tape-like wire 50 is supplied with atmospheric gas over the longitudinal direction of the rotating body 12 in the furnace core tube 11. In this rotating body 12, as shown in FIG. 7, at one end portion side (lid body 12c side) on the gas discharge pipe 14 side and at the other end portion (lid body 12d side) on the side away from the gas discharge pipe 14 There is no difference in the displacement of hydrogen fluoride gas.

  As described above, since there is no difference in the gas exhaust amount in the vicinity of both ends of the rotating body 12, in the tape-shaped wire 50 wound around the rotating body 12, the portions R and Q located in the vicinity of both ends of the rotating body 12. There is no difference in the removal rate of fluorine. Thereby, an oxide superconducting wire having uniform superconducting characteristics in the length direction can be easily obtained by applying the MOD method.

<Modification>
FIG. 10 is a diagram schematically showing a modified example of the rotating body of the heat treatment apparatus according to the present invention. The heat treatment apparatus provided with the rotating body 90 has the same basic structure as the heat treatment apparatus 10 corresponding to the first embodiment shown in FIG. 3 except for the rotating body 90 and the gas exhaust pipe 97. Therefore, the description is omitted.

  In other words, the heat treatment apparatus including the rotator 90 as a modification includes the rotator 90 and the gas exhaust pipe 97 illustrated in FIG. 10 instead of the rotator 12 and the gas exhaust pipe 14 in the heat treatment apparatus 10 illustrated in FIG. 3.

  A rotating body 90 shown in FIG. 10 has a cylindrical shape, a cylindrical rotating body main body 91 having an outer diameter at the center portion smaller than the outer diameters at both ends, and a lid for closing both end surfaces of the rotating body main body 91. And bodies 93 and 95. Gas discharge pipes 97 a and 97 b are connected to the lid bodies 93 and 95.

  The surface of the rotator main body 91 in the rotator 90 has two conical circumferences that reduce in diameter from the lids 93 and 95 at both ends to which the gas discharge pipes 97 a and 97 b are connected toward the center of the rotator 90. Surfaces 91 a and 91 b are provided, and the conical circumferential surfaces 91 a and 92 b are continuous at the center of the rotating body 90.

  Specifically, the rotator main body 91 has a cylindrical shape in which the top and bottom of the truncated cone are joined, and is inclined from both end portions separated in the longitudinal direction (axial direction) toward the central portion in the longitudinal direction. It is formed as follows.

  In the rotating body 91, the lower bottom of the truncated cone is closed with lids 93 and 95 to which gas exhaust pipes 97a and 97b are connected. Here, the gas discharge pipes 97a and 97b are both ends of the gas discharge pipe 97 inserted on the rotation shaft (corresponding to the furnace core axis C) of the rotating body main body 91. A plurality of holes are formed in a central portion of the gas discharge pipe 97 and a portion located in the rotary body main body 91, and the inside of the gas discharge pipe 97 and the rotary body main body 91 are in communication with each other. .

  In the heat treatment apparatus including the rotating body 90 configured as described above, the same amount of exhaust gas is exhausted through the exhaust pipes 97a and 97b. For example, the same amount of exhaust gas is sucked from the gas discharge pipes 97a and 97b by a suction device. That is, in the configuration of the rotator 90, exhaust gas (hydrogen fluoride gas) is discharged from both end sides. At this time, as indicated by an arrow, the flow rate of the exhaust gas (hydrogen fluoride gas) is constant in the longitudinal direction. Thereby, similarly to Embodiment 1, an excellent oxide superconducting wire having uniform superconducting characteristics in the length direction can be obtained.

In the heat treatment apparatus 10, the gas supply pipes 13 are formed with a length of 2 m and an inner diameter of 20 mmφ, and the gas injection holes 20 are formed in the gas supply pipes 13 at a pitch of 30 mm in the longitudinal direction of the gas supply pipes 13. (Nozzle diameter) was formed at 1.0 mmφ. At this time, the pressure in the furnace core tube 11, that is, the pressure in the heat treatment space 11a, was set to 50 to 200 torr, and the gas flow rate was set to 250 to 1000 L / min (converted value at normal temperature and normal pressure). Then, the flow rate of the atmospheric gas ejected from the gas ejection holes 20 in the heat treatment apparatus 10 and supplied to the surface 12a of the rotator 12 (the flow rate in contact with the film surface of the film body wound around the rotator) is: It was 300 m / s. The angle x is a rotating body 12 of 5 degrees. The film body of the tape-shaped wire 50 wound around the rotating body 12 is formed by forming a Gd ₂ Zr ₂ O ₇ intermediate layer as a template on the tape-shaped Ni alloy substrate (base material) by the IBAD method, Further, a Y-TFA salt (trifluoroacetate salt), a Ba-TFA salt, and a Cu-naphthenate salt are added in an organic solvent on a composite substrate on which a CeO ₂ intermediate layer is formed by sputtering. A film body obtained by applying a mixed solution (superconducting raw material solution) dissolved at a ratio of Y: Ba: Cu = 1: 1.5: 3 by a dip coating method and then pre-baking in a pre-baking step. The film body was heat-treated by a main baking step at a furnace temperature of 750 ° C. to obtain a 1.5 μm superconducting layer.

  Thus, the heat processing apparatus provided with the rotary body which made the angle x 5 degree | times is made into Example 1, and the example which changed this angle suitably is set as Examples 2-4. The following table shows the difference in the characteristics of each part in the oxide superconducting wire positioned.

  In the second embodiment, the angle x = 3 degrees, in the third embodiment, the angle x = 8 degrees, and in the fourth embodiment, the angle x = 10 degrees. As Reference Example 1, a difference in characteristics between portions located at both ends of the rotating body 12 with an angle x = 0 degrees is described. Further, as Reference Examples 2 and 3, angles x = 15 degrees and 175 degrees, and the difference in characteristics of each part in the oxide superconducting wire positioned at both ends of the rotating body 12 is shown in the following table for each angle. .

  In the oxide superconducting wires made by the heat treatment apparatuses of Examples 1 to 4 and Reference Examples 1 to 3, the difference in the characteristics of the portions located at both ends of the rotating body 12 was as follows.

  Thus, when the angle x is 0 degree <x ≦ 10 degrees, in the generated oxide superconducting wire, the difference in the characteristics of the portions separated in the length direction is 50 Ic or less, and the angle x is 0 degree <x ≦ At 5 degrees, in the generated oxide superconducting wire, the difference in the characteristics of the portions separated in the length direction was 30 Ic or less.

  Thus, the method for producing a tape-shaped oxide superconducting wire using the heat treatment apparatus of the example is more produced than the method for producing a tape-shaped oxide superconducting wire using the heat treatment apparatus of each reference example. There was no difference in the characteristics of the superconducting wire in the length direction, and it was possible to have excellent uniform characteristics.

  Furthermore, since firing is performed in a batch mode, the atmosphere in the furnace can be controlled more easily than in the case of firing in a reel-to-reel mode, so a stable superconducting layer can be formed, and the oxide can be formed in a short time. Superconducting wire can be manufactured.

  The present invention can be variously modified without departing from the spirit of the present invention, and the present invention naturally extends to the modified ones.

  The oxide superconducting wire manufacturing method and heat treatment apparatus according to the present invention have the effect of producing a tape-shaped oxide superconducting wire having excellent superconducting properties that are uniform in the length direction, and tape-shaped oxidation using the MOD method. It is widely applicable when forming a superconducting wire.

DESCRIPTION OF SYMBOLS 10 Heat processing apparatus 11 Furnace core pipe 12, 90 Rotating body 12a Surface 12b, 91 Rotating body main body 13 Gas supply pipe 14, 97, 97a, 97b Gas exhaust pipe 20 Gas ejection hole 50 Tape-like wire rod C Core core

Claims (9)

A furnace core tube with a cylindrical heat treatment space;
Inside the heat treatment space, a tape-like wire rod having a superconducting precursor film formed on a surface on which a large number of through holes are formed and arranged rotatably about the core axis of the furnace core tube is provided. A cylindrical rotating body to be wound;
A gas supply pipe that supplies an atmospheric gas to the film surface of the film body in the tape-like wire rod disposed on the surface of the furnace core so as to face the surface of the rotating body. When,
A gas discharge pipe for discharging the gas after reacting with the film body from the inside of the rotating body to the outside of the furnace core pipe;
In the method of manufacturing an oxide superconducting wire using a heat treatment apparatus comprising:
The surface of the rotating body has a conical circumferential surface whose diameter is reduced in the furnace core axis direction,
A tape-like wire material on which the film body of the superconducting precursor is formed is wound around the conical circumferential surface, and the atmospheric gas is supplied over the longitudinal direction of the rotating body.
Tape-like oxide superconducting wire manufacturing method. The gas exhaust pipe is connected to at least one end of both ends of the rotating body, and the inside of the gas exhaust pipe communicates with the inside of the rotating body,
The conical circumferential surface is reduced in diameter from the one end side to which the gas discharge pipe is connected toward the other end side of the rotating body.
A method for producing a tape-shaped oxide superconducting wire according to claim 1. In the cylindrical rotating body, an angle formed by a generatrix line passing through the one end portion and a virtual line parallel to the furnace core axis passing through the one end portion is greater than 0 degree and 10 degrees. Is
A method for producing a tape-shaped oxide superconducting wire according to claim 2. The gas exhaust pipe is connected to both ends of the rotating body,
The inside of each of the gas discharge pipes communicates with the inside of the rotating body,
The surface of the rotating body includes two conical circumferential surfaces that reduce in diameter from each of both ends to which the gas discharge pipe is connected toward the center of the rotating body,
These conical circumferential surfaces are continuous at the center of the rotating body,
A method for producing a tape-shaped oxide superconducting wire according to claim 1. The gas supply pipe supplies an atmospheric gas to the film surface on the surface of the rotating body through a large number of gas ejection holes arranged in parallel with the furnace core axis.
The manufacturing method of the tape-shaped oxide superconducting wire as described in any one of Claim 1 to 4. The superconducting precursor film body forms an intermediate layer on the substrate, and after applying a mixed solution prepared by dissolving a metal organic acid salt or organic metal compound containing a metal element in an organic solvent on the intermediate layer, pre-baking A film body formed by
The manufacturing method of the tape-shaped oxide superconducting wire as described in any one of Claim 1 to 5. The metal organic acid salt containing a metal element in the mixed solution consists of one or more selected from octylate, naphthenate, neodecanoate or trifluoride acetate.
The manufacturing method of the tape-shaped oxide superconducting wire as described in any one of Claim 1 to 6. The oxide superconducting wire comprises an intermediate layer formed on the substrate, a REBa _y Cu ₃ O _z- based superconducting layer formed on the intermediate layer, a stabilization layer formed on the superconducting layer, The tape-shaped oxide superconducting wire according to any one of claims 1 to 7, wherein the RE is composed of one or more elements selected from Y, Nd, Sm, Eu, Gd, and Ho. Production method. A furnace core tube with a cylindrical heat treatment space;
Inside the heat treatment space, a tape-shaped wire rod is disposed that is rotatable with respect to the furnace core axis of the furnace core tube, and a film body of a superconducting precursor is formed on a surface on which a large number of through holes are formed. A cylindrical rotating body to be wound;
A gas supply pipe that supplies an atmospheric gas to the film surface of the film body in the tape-like wire rod disposed on the surface of the furnace core so as to face the surface of the rotating body. When,
A gas discharge pipe for discharging the gas after reacting with the film body from the inside of the rotating body to the outside of the furnace core pipe;
A heat treatment apparatus comprising:
The gas exhaust pipe is connected to at least one end portion of both end portions of the rotating body so as to communicate the inside of the gas exhaust pipe with the interior of the rotating body,
The surface of the rotating body has a conical circumferential surface whose diameter is reduced in the furnace core axis direction.
Heat treatment equipment.

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