JP3756322B2 - Manufacturing apparatus and manufacturing method of oxide superconducting conductor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a superconducting power cable, a superconducting magnet, a superconducting energy storage device, a superconducting power generation device, a medical MRI apparatus, a superconducting current lead, and the like.
[0002]
[Prior art]
As a conventional method for producing an oxide superconducting conductor, oxide superconducting powder or a powder that becomes an oxide superconductor by heat treatment is pressed into a cylindrical shape, and this is inserted into a silver tube to be drawn and rolled, and a heat treatment step. In addition to solid-phase methods such as powder-in-tube method (PIT method) for forming wire rods, metal tapes by vapor deposition methods such as chemical vapor deposition method (CVD method) and physical vapor deposition method (PVD method) A film forming method is known in which an oxide-based superconducting layer is continuously formed on a long base material such as the above.
In addition, when an oxide superconducting layer is formed by vapor deposition, if the oxide superconducting layer is directly formed on a metal base material, the base material itself is a polycrystal and the crystal structure thereof is larger than that of the oxide superconductor. There is a problem that an oxide superconducting layer with good crystal orientation cannot be formed due to the difference, and in order to improve this, as shown in FIG. A, a YSZ (YSZ ( A polycrystalline intermediate layer 92 such as yttria-stabilized zirconia), a Y-Ba-Cu-O-based superconducting layer 93 is formed on the polycrystalline intermediate layer 92, and a stabilizing layer made of silver or the like is further formed thereon. Various attempts have been made to produce oxide superconducting conductors with excellent superconducting properties by forming 94.
[0003]
Among such attempts, the present inventors have previously made a tape such as a Hastelloy tape to form a polycrystalline intermediate layer having excellent crystal orientation or to obtain a superconducting conductor having excellent superconducting properties. A method of forming a polycrystalline intermediate layer while irradiating an ion beam from an oblique direction of the substrate film forming surface simultaneously with sputtering when forming a polycrystalline intermediate layer on a substrate with a sputtering device (ion beam assisted sputtering) Method), a polycrystalline intermediate layer having excellent crystal orientation can be formed.
According to this method, the grain boundary inclination angle formed by the a-axis or b-axis of each crystal lattice of a large number of crystal grains forming the polycrystalline intermediate layer can be adjusted to 30 degrees or less, and the crystal orientation is excellent. A polycrystalline intermediate layer (orientation controlled polycrystalline intermediate layer) can be formed. Furthermore, if a Y—Ba—Cu—O-based superconducting layer is formed on this orientation controlled polycrystalline intermediate layer by vapor deposition or the like, the crystal orientation of the oxide superconducting layer will be excellent, thereby An oxide superconductor having a high critical current density can be produced.
[0004]
[Problems to be solved by the invention]
However, an oxide superconducting conductor produced by a vapor phase method such as a laser vapor deposition method or a CVD method has a higher critical current density than an oxide superconducting conductor produced by a solid phase method such as a PIT method. There was a problem that the critical current was small. This is because the oxide superconducting conductor produced by the vapor phase method has good crystal orientation of the oxide superconducting layer, but it is difficult to increase the thickness of the oxide superconducting layer. Therefore, high critical current is important for practical use of long oxide superconducting conductors, and in particular, a critical current of at least several tens of A level is required for application to superconducting magnets. It has been realized.
[0005]
This invention is made | formed in view of the said situation, and it is providing the manufacturing apparatus and manufacturing method of an oxide superconductor which can manufacture an oxide superconductor with a high critical current.
[0006]
[Means for Solving the Problems]
In order to produce an oxide superconductor having a high critical current, the present inventor has paid attention to the structure of the oxide superconductor in particular, and as a result of various studies and experiments, the structure of the oxide superconductor has been converted into a tape-like structure. Compared to an oxide superconducting conductor in which an oxide superconducting layer is formed only on one side of a tape-like substrate by assuming that an oxide superconducting layer is formed on both sides of the substrate via a polycrystalline intermediate layer. It has been estimated that about twice the critical current can be obtained.
[0007]
However, a conventional oxide superconducting conductor manufacturing apparatus using a CVD reactor that deposits a thin film on a substrate can form an oxide superconducting layer on only one surface of a tape-like substrate. When forming an oxide superconducting layer on both sides of the material, after forming the oxide superconducting layer on one side of the tape-shaped substrate first, the oxide superconducting layer must be formed on the other side. Therefore, when the oxide superconducting layer is formed in the second time, the first oxide superconducting layer previously formed is deteriorated or the characteristics of the oxide superconducting layers on both sides are greatly different. In addition, an oxide superconducting conductor manufacturing apparatus and manufacturing method for forming an oxide superconducting layer on both surfaces of a tape-shaped substrate at one time have not been established. It has not yet arrived There.
And, as a result of further various examinations and experiments, the present inventor, according to the following oxide superconducting conductor manufacturing apparatus and manufacturing method, the oxide superconducting layer is formed on both surfaces of the tape-shaped substrate. The present inventors completed the present invention by investigating that an oxide superconducting conductor having a high critical current can be formed at a time.
[0008]
  That is, the invention according to claim 1 is a CVD reaction in which an oxide superconducting layer is formed by chemically reacting a raw material gas of an oxide superconductor on both surfaces during movement of a tape-like substrate fed into the inside. And a gas diffusion part connected to a source gas supply source and supplying the source gas into the reactor,
  The gas diffusion portion is provided at a gas diffusion member attached to the reactor, a gas introduction pipe connected to the gas diffusion member and supplying the source gas to the gas diffusion member, and a tip of the gas introduction pipe The cross-sectional shape formed is a slit nozzle having a rectangular slit,
  The gas diffusion member is provided in a direction intersecting the longitudinal direction of the tape-shaped substrate, a pair of opposing side walls provided along the longitudinal direction of the substrate of the tape fed into the reactor, A front wall and a rear wall connecting the pair of side walls to each other; a distance between the front wall and the rear wall becomes wider as the reactor is approached; and a distance between the pair of side walls is the front wall and the rear wall It is a certain size narrower than the interval of
  The oxide superconducting conductor manufacturing apparatus is characterized in that the slit of the slit nozzle is provided in a direction in which the long side intersects the longitudinal direction of the tape-like substrate moving in the reactor. As a solution to the problem.
  The front wall and the rear wall of the gas diffusion member are preferably provided in a direction orthogonal to the longitudinal direction of the tape-shaped substrate.
  Moreover, it is preferable that the slit of the slit nozzle is provided in a direction perpendicular to the longitudinal direction of the tape-shaped substrate that is moving in the reactor.
[0009]
  Claims2The described invention is claimed.1Using the oxide superconducting conductor manufacturing apparatus described above, the tape-shaped base material was fed into the reactor so that the superconducting layer forming surfaces on both sides thereof were parallel to the flow of the source gas from the slit nozzle, While supplying the raw material gas of the oxide superconductor from the gas supply source through the gas diffusion section into the reactor, and further heating the tape-like base material to deposit reaction products on both sides of the base material A manufacturing method of an oxide superconducting conductor characterized in that a CVD reaction is performed was used as a means for solving the above problems.
  Claims3The invention described in claim 1 is characterized in that the tape-like base material has a polycrystalline intermediate layer formed on both sides.2The manufacturing method of the oxide superconducting conductor described was used as a means for solving the above problems.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in more detail with reference to the drawings.
FIG. 1 shows an example of an apparatus for manufacturing an oxide superconducting conductor according to the present invention. In the manufacturing apparatus of this example, a CVD reactor 30 whose detailed structure is shown in FIGS. In the CVD reactor 30, oxide superconducting layers are formed on both surfaces of a tape-like substrate at once.
The CVD reactor 30 shown in FIGS. 2 to 5 used in the manufacturing apparatus of this example is connected to a cylindrical quartz reactor 31 closed at both ends and a vaporizer (source gas supply source) 62. It has a gas diffusion part 40. The reactor 31 is divided into a base material introduction part 34, a reaction generation chamber 35, and a base material outlet part 36 in order from the left side of FIG. The material constituting the reactor 31 is not limited to quartz but may be a metal having excellent corrosion resistance such as stainless steel.
[0011]
A passage hole 39 through which a long tape-like base material 38 can pass is formed in the lower center of the partition walls 32 and 33, and the base material is conveyed inside the reactor 31 so as to cross the central portion thereof. Region R is formed. Furthermore, an introduction hole for introducing the tape-like base material 38 is formed in the base material introduction part 34, and a lead-out hole for leading out the base material 38 is formed in the base material lead-out part 36. A sealing mechanism (not shown) that holds the base material introduction part 34 and the base material lead-out part 36 in an airtight state by closing the gap between the holes in the peripheral part of the hole and the lead-out hole while allowing the base material 38 to pass therethrough. ) Is provided.
[0012]
A substantially pyramid-shaped gas diffusion section 40 is attached to the ceiling of the reaction generation chamber 35 as shown in FIG. The gas diffusion section 40 is connected to a gas diffusion member 45 attached to the reactor 31 and a ceiling wall 44 of the gas diffusion member 45, and a gas introduction pipe 53 that supplies the raw material gas of the oxide superconductor to the gas diffusion member 45. And a slit nozzle 54 provided at the distal end portion of the gas introduction pipe 53.
[0013]
  The gas diffusion member 45 includes a pair of opposing trapezoidal side walls 41, 41 provided along the longitudinal direction of the base material 38 of the tape fed into the reactor 31, and the longitudinal direction of the tape-shaped base material 38. The front wall 42 and the rear wall 43 are provided in a direction orthogonal to each other and connect the pair of side walls 41 and 41 to each other, and the ceiling wall 44.. in frontThe distance between the face wall 42 and the rear wall 43 becomes wider as the reactor 31 is approached. The bottom surface of the gas diffusion member 45 is an elongated rectangular opening 46, and the gas diffusion member 45 communicates with the reaction generation chamber 35 through the opening 46. As shown in FIG. 6, the slit nozzle 54 has a slit 54 a having a rectangular cross-sectional shape, and the long side 54 c of the slit 54 a is moved in the reactor 31 in the longitudinal direction of the tape-like substrate 38. It is provided in the direction orthogonal to. The size of the long side 54 c of the slit 54 a is about the same size as the inner diameter of the gas introduction pipe 53.
[0014]
On the other hand, an exhaust chamber 70 is provided below the reaction generation chamber 35 along the length direction of the substrate transport region R as shown in FIGS. As shown in FIGS. 2 and 5, rectangular gas exhaust holes 70a and 70a that are elongated along the length direction of the tape-shaped substrate 18 passed through the substrate conveyance region R are formed in the upper portion of the exhaust chamber 70. Each is formed.
One end of a plurality (four in the drawing) of exhaust pipes 70 b is connected to the lower portion of the exhaust chamber 70, while the other end of the plurality of exhaust pipes 70 b is a pressure provided with a vacuum pump 71. The adjustment device 72 is connected. Further, as shown in FIGS. 3 to 5, the exhaust ports 70c of a plurality (two in the drawing) of the plurality of exhaust pipes 70b are tape-shaped through the base material transport region R. The base material 38 is provided along the length direction. Further, the exhaust ports 70c of the remaining (two in the drawing) exhaust pipes 70b among the plurality of exhaust pipes 70b intersect with the length direction of the tape-shaped base material 38 passed through the base material transport region R. Is provided. Each of the plurality of exhaust pipes 70b is provided with a valve (flow rate adjusting mechanism) 70d for adjusting the exhaust amount of gas. Therefore, the gas exhaust mechanism 80 is constituted by the exhaust chamber 70 in which the gas exhaust holes 70a, 70a are formed, the plurality of exhaust pipes 70b,..., The valve 70d, the vacuum pump 71, and the pressure adjusting device 72. . The gas exhaust mechanism 80 having such a configuration can exhaust gases such as source gas, oxygen gas, and inert gas inside the CVD reactor 30 from the gas exhaust holes 70a and 70a through the exhaust chamber 70 and the exhaust pipe 70b. It has become.
[0015]
As shown in FIG. 1, a heater 47 is provided outside the CVD reaction apparatus 30 to cover a portion of the base material introduction section 34 on the reaction generation chamber 35 side and a portion of the base material outlet section 36 on the reaction generation chamber 35 side. The base material introduction part 34 is connected to the inert gas supply source 50, and the base material lead-out part 36 is connected to the oxygen gas supply source 51. In addition, the gas introduction pipe 53 connected to the ceiling wall 44 of the gas diffusion unit 40 is connected to a vaporizer (source gas supply source) 62.
An oxygen gas supply source 52 is branched and connected to an intermediate portion of the gas introduction pipe 53 via an oxygen gas flow rate adjusting mechanism 52 a so that oxygen gas can be supplied to the gas introduction pipe 53. .
[0016]
The vaporizer 62 is connected to the liquid raw material supply device 55 by accommodating the tip from the center of the liquid raw material supply device 55 described later.
Further, a heater 63 for heating the inside of the vaporizer 62 is attached to the outer peripheral portion of the vaporizer 62, and a mist-like raw material solution sprayed from the nozzle 59 of the liquid raw material supply device 55 by the heater 63. 66 is heated to a desired temperature and vaporized to obtain a raw material gas.
[0017]
As shown in FIG. 1, the liquid raw material supply device 55 includes a cylindrical raw material solution supply unit 56, a cylindrical and tapered atomized gas supply unit 57 provided around the outer periphery of the supply unit 56, and The atomizing gas supply unit 57 has a triple structure which is schematically configured from a cylindrical shield gas supply unit 58 provided so as to surround the outer periphery excluding the tip.
The raw material solution supply unit 56 is supplied with a raw material solution 66 sent from a raw solution supply device 65 described later, and a liquid pool 56a for temporarily storing the supplied raw material solution 66 in the center. Is provided. The inner diameter of the liquid pool 56a is larger than the inner diameter of the upper end portion or the lower end portion of the raw material solution supply unit 56, and the raw material solution 66 sent from the stock solution supply device 65 is continuously sent to the tip while accumulating. It is like that.
The atomizing gas supply unit 57 supplies atomizing gas for atomizing the raw material solution 66 into the gap with the raw material solution supply unit 56. An atomizing gas supply source 60 is connected to the upper part of the atomizing gas supply unit 57 via an atomizing gas MFC 60 a so that atomizing gas such as argon gas, helium gas, nitrogen gas, etc. can be supplied into the atomizing gas supply unit 57. It is configured.
[0018]
The shield gas supply unit 58 is supplied with a shield gas for cooling the atomization gas supply unit 57 and shielding the nozzle 59 in a gap with the atomization gas supply unit 57. The nozzle 59 here is composed of a tip portion of the atomizing gas supply unit 57 and a tip portion of the raw material solution supply unit 56. In addition, a shield gas 61 is connected to the upper part of the shield gas supply unit 58 via a shield gas MFC 61a so that a shield gas such as argon gas, helium gas, or nitrogen gas can be supplied into the shield gas supply unit 58. It is configured.
[0019]
In the liquid raw material supply device 55 described above, when the raw material solution 66 is fed into the raw material solution supply unit 56 at a constant flow rate and the atomized gas is fed into the atomizing gas supply unit 57 at a constant flow rate, the raw material solution 66 is accumulated in the liquid pool 56a. Although reaching the tip of the raw material solution supply unit 56, the atomized gas flows from the tip of the atomizing gas supply unit 57 outside the tip, so that the raw material solution 66 is immediately atomized by the atomizing gas when blown from the nozzle 59. A certain amount of mist-like liquid solution can be continuously supplied into the vaporizer (source gas supply source) 62.
In addition, when the shielding gas is sent to the shielding gas supply unit 58 at a constant flow rate, the atomizing gas supply unit 57 and the raw material solution supply unit 56 are cooled, so that the raw material solution 66 flowing in the raw material solution supply unit 56 is also cooled. The raw material solution 66 can be prevented from being vaporized in the middle. Furthermore, since the shielding gas flows outside the nozzle 59 and from the tip of the upper shielding gas supply unit 58, the periphery of the nozzle 59 is shielded by the shielding gas, and the raw material solution 66 is vaporized in the vaporizer 62. Thus, it is possible to prevent the raw material gas from adhering to the nozzle 59 and becoming a solid raw material and reprecipitating.
[0020]
A raw solution supply device 65 is connected to the raw material solution supply unit 56 of the liquid raw material supply device 55 through a connection pipe 67 provided with a pressurized liquid pump 67a.
The stock solution supply device 65 includes a storage container 68 and a purge gas source 69 that makes the inside of the container 68 an inert atmosphere. A raw material solution 66 is stored in the storage container 68. The raw material solution 66 is sucked by the pressurized liquid pump 67 a and transported at a constant flow rate to the raw material solution supply unit 56.
[0021]
Further, a tension drum 73 and a winding drum 74 for winding the tape-shaped substrate 38 that passes through the substrate conveyance region R in the reactor 31 are disposed on the side of the substrate lead-out portion 36 of the CVD reactor 30. The base material conveyance mechanism 75 which consists of these is provided. Further, on the side of the base material introducing portion 34, a base material transport mechanism 78 including a tension drum 76 and a feed drum 77 for supplying the tape-shaped base material 38 to the CVD reactor 30 is provided. .
[0022]
Further, a flow meter (not shown) for measuring the flow of gas such as raw material gas and oxygen gas is attached in the base material conveyance region R of the reactor 31, and a control mechanism 82 is electrically connected to the flow meter and the valve 70d. It is connected to the. The control mechanism 82 adjusts each valve 70d based on the measurement result of the flow meter, and intersects the length direction of the tape-like base material 38 moving in the reactor 31 and the length direction of the base material 38. It is possible to control the flow state of the gas such as the raw material gas and oxygen gas in the direction in which the gas flows.
Further, the control mechanism 82 is electrically connected to the oxygen gas flow rate adjusting mechanism 52a, thereby adjusting the operation of the oxygen gas flow rate adjusting mechanism 52a based on the measurement result of the flow meter in the substrate transport region R, and introducing the gas. It is preferable that the amount of oxygen gas sent to the CVD reactor 30 via the tube 53 can be adjusted.
[0023]
Next, an oxide superconducting layer is formed on a tape-shaped substrate 38 using an oxide superconducting conductor manufacturing apparatus having the CVD reactor 30 configured as described above, and an oxide superconducting conductor is manufactured. Will be described.
In order to manufacture an oxide superconducting conductor using the manufacturing apparatus shown in FIG. 1, first, a tape-shaped substrate 38 and a raw material solution are prepared.
A long substrate can be used as the substrate 38, and in particular, a substrate formed by coating a ceramic intermediate layer on both surfaces of a heat-resistant metal tape having a low thermal expansion coefficient is preferable. As a constituent material of the heat-resistant metal tape, metal materials such as silver, platinum, stainless steel, copper, Hastelloy (C276, etc.) and alloys are preferable. In addition to the metal tape, a tape made of various ceramics such as various glass tapes or mica tapes may be used.
Next, the material constituting the intermediate layer is composed of YSZ (yttrium stabilized zirconia), SrTiO whose thermal expansion coefficient is closer to that of the oxide superconductor than metal._Three, MgO, Al₂O_ThreeLaAlO_ThreeLaGaO_ThreeYAlO_Three, ZrO₂Ceramics such as these are preferable, and among these, it is preferable to use one having as much crystal orientation as possible.
[0024]
Next, the raw material solution for generating the oxide superconductor by the CVD reaction is preferably a solution in which a metal complex of each element constituting the oxide superconductor is dispersed in a solvent. Specifically, Y₁Ba₂Cu_ThreeO_7-xIn the case of forming a Y-based oxide superconducting layer widely known in the composition, Ba-bis-2,2,6,6-tetramethyl-3,5-heptanedione-bis-1,10-phenanthroline (Ba (Thd)₂(Phen)₂) And Y (thd)₂ And Cu (thd)₂Can be used (thd = 2,2,6,6-tetramethyl-3,5-heptanedione, phen = 1,10-phenanthroline), otherwise Y-bis-2,2,6, 6-Tetramethyl-3,5-heptanedionate (Y (DPM)_Three) And Ba (DPM)₂And Cu (DPM)₂Etc. can be used.
[0025]
In addition to the Y-based oxide superconducting layer, La oxide_2-xBa_xCuO_FourLa-based, Bi represented by the composition of₂Sr₂Ca_n-1Cu_nO_{2n + 2}Bi type represented by the composition of (n is a natural number), Tl₂Ba₂Ca_n-1Cu_nO_{2n + 2}Since various types of superconducting layers such as Tl-based materials represented by the composition (n is a natural number) are known, the CVD method may be carried out using a metal complex salt corresponding to the target composition.
Here, for example, in the case of producing an oxide superconducting layer other than Y, triphenylbismuth (III), bis (dipivalomethanato) strontium (II), bis (di A metal complex salt such as pivalloymethanato) calcium (II) or tris (dipivalloymethanato) lanthanum (III) can be appropriately used for the production of the oxide superconducting layer of each system.
[0026]
If the tape-like base material 38 having the polycrystalline intermediate layer formed on both sides is prepared, the base material is introduced into the base material transport region R in the reactor 31 of the CVD reactor 30 by the base material transport mechanism 78. The substrate 34 is fed from the section 34 at a predetermined moving speed, wound by the winding drum 74 of the substrate transport mechanism 68, and further the substrate 38 in the reaction generation chamber 35 is heated to a predetermined temperature by the heater 47. Here, when the tape-shaped substrate 38 is fed into the reactor 31, the tape-shaped substrate 38 is fed so that one end surface 38 b in the width direction of the tape-shaped substrate 38 faces the slit 54 a of the slit nozzle 54. The superconducting layer forming surfaces 38 a on both sides of the base material 38 are fed so as to be parallel to the flow of the source gas from the slit nozzle 54.
Before feeding the tape-shaped substrate 38, the inert gas is fed from the inert gas supply source 50 into the CVD reactor 30 as a purge gas, and at the same time, the gas inside the CVD reactor 30 is gasified by the pressure regulator 72. It is preferable to remove the unnecessary gas such as air in the CVD reactor 30 by cleaning it from the exhaust holes 70a and 70a through the exhaust chamber 70, exhaust port 70c and exhaust pipe 70b.
[0027]
If the base material 38 is sent into the reactor 31, oxygen gas is sent into the CVD reactor 30 from the oxygen gas supply source 51, and the raw material container 66 is further fed from the storage container 68 to the flow rate of 0.1 to 0.1 by the pressurized liquid pump 67a. At about 10 ccm, liquid is fed into the raw material solution supply unit 56, and at the same time, atomized gas is fed into the atomized gas supply unit 57 at a flow rate of about 200 to 550 ccm and shield gas is fed into the shield gas supply unit 58 at a flow rate of about 200 to 550 cc. . At the same time, the gas inside the CVD reactor 30 is exhausted from the gas exhaust holes 70a and 70a through the exhaust chamber 70, the exhaust port 70c, and the exhaust pipe 70b by the pressure adjusting device 72. At this time, the temperature of the shielding gas is adjusted to be about room temperature. Further, the heater 63 is adjusted so that the internal temperature of the vaporizer 62 becomes the optimum temperature of the raw material having the highest vaporization temperature among the raw materials.
[0028]
Then, the liquid raw material 66 reaches the front end of the raw material solution supply unit 56 while accumulating in the liquid pool 56a, and then is immediately atomized by the atomizing gas flowing from the atomizing gas supply unit 57 when blown out from the nozzle 59. A mist-like liquid solution 34 having a constant flow rate is continuously supplied into the vaporizer 62. The mist-like raw material solution 66 supplied to the inside of the vaporizer 62 is heated and vaporized by the heater 63 to become a raw material gas, and this raw material gas continues to the gas diffusion member 45 through the gas introduction pipe 53. Supplied. At this time, it is adjusted by the heating means so that the internal temperature of the gas introduction pipe 53 becomes the optimum temperature of the raw material having the highest vaporization temperature among the raw materials. At the same time, an operation of supplying oxygen gas from the oxygen gas supply source 52 and mixing oxygen into the source gas is also performed.
[0029]
Next, in the CVD reaction apparatus 30, the raw material gas fed into the gas diffusion member 45 from the slit nozzle 54 at the tip of the gas introduction pipe 53 is fed into the reactor 31 in the gas diffusion member 45. It moves to the reaction generation chamber 35 side while diffusing in a direction parallel to the length direction of the substrate 38 (while diffusing along the front wall 42 and the rear wall 43 of the gas diffusion member 45). At this time, the diffusion of the raw material gas in the direction perpendicular to the length direction of the tape-like base material 38 fed into the reactor 31 is suppressed.
[0030]
Next, the raw material gas that has moved to the reaction generation chamber 35 side moves downward from above the reaction generation chamber 35. At this time, the tape-like base material 38 is fed into the reactor 31 so that the superconducting layer forming surfaces 38a on both sides are parallel to the flow of the raw material gas from the slit nozzle 54 as described above. The raw material gas reacts on both sides of the base material 38, and the reaction product is deposited on the superconducting layer forming surfaces 38a on both sides.
The remaining raw material gas that does not contribute to the reaction is drawn into the gas exhaust holes 70a and 70a.
[0031]
When depositing a reaction product on the superconducting formation surface 38a of the tape-like substrate 38, the pressure adjusting device 72 provided in the gas exhaust mechanism 80 is used to discharge the exhaust chamber 70, the exhaust port 70c, and the exhaust pipe from the gas exhaust holes 70a and 70a. The length of the tape-like base material 38 moving in the base material transport region R and the base material are adjusted by adjusting each valve 70d and adjusting the gas flow in each exhaust pipe 70b by exhausting through the base material 70b. The CVD reaction is performed while controlling the flow state of the source gas in the direction intersecting the length direction of 38.
Further, while the reaction proceeds in the reaction generation chamber 35, the raw material in the length direction of the tape-like base material 38 moving in the base material transport region R and the direction orthogonal to the length direction of the base material 38 Since the flow state of gas such as gas or oxygen gas may change and adversely affect the oxide superconducting layer, measure the change in gas flow rate with the flow meter provided in the substrate transport area R. Based on this measurement result, the control mechanism 82 adjusts the amount of oxygen gas supplied from each valve 70d and the oxygen gas supply source 52 to control the gas flow state to always be a preferable flow state.
[0032]
Further, while the reaction proceeds in the reaction generation chamber 35, deposits increase in the reaction generation chamber 35 and the like, and when this deposit undergoes a decomposition reaction by heating to release gas, The oxygen gas partial pressure may be different from the target partial pressure, or the temperature inside the reaction generation chamber 35 may become non-uniform. In such a case, since the oxygen concentration in the exhaust gas discharged through the exhaust pipe 70b changes, this change in concentration is detected by an oxygen analyzer / measurement device (not shown) provided in the middle of the exhaust pipe 70b. When the oxygen concentration decreases, the control mechanism 82 increases the amount of oxygen gas sent to the CVD reactor 30 at a predetermined rate according to the shortage, and when the oxygen concentration increases, the control mechanism 82 increases the predetermined amount according to the increase. At a rate, the control mechanism 82 reduces the amount of oxygen gas sent to the CVD reactor 30. By such an action of the control device 82, the oxygen partial pressure in the reaction generation chamber 35 can be kept constant at all times, so that the CVD reaction can always occur at a constant oxygen partial pressure. Therefore, a uniform oxide superconducting layer can be formed on both surfaces of the tape-shaped substrate 38. After the formation of the oxide superconducting layer, heat treatment for adjusting the crystal structure of the oxide superconducting layer may be performed as necessary.
[0033]
Next, when a stabilizing layer made of silver or the like is formed on the double-sided oxide superconducting layers formed as described above by vapor deposition or the like, an oxide superconducting conductor 85 as shown in FIG. 7 is obtained. In this oxide superconducting conductor 85, an oxide superconducting layer 86 is formed on both surfaces of a tape-like substrate 38 via a polycrystalline intermediate layer 86, and a stabilization layer 88 is formed on each oxide superconducting layer 86. It is a structured.
As a specific example of the thickness of each layer of the oxide superconducting conductor 85 having such a structure, the thickness of the tape-shaped substrate 38 is about 50 to 200 μm, and the thickness of the polycrystalline intermediate layer 86 is about 0.5 to 1.0 μm. The thickness of the oxide superconducting layer 86 is about 1 to 5 μm, and the thickness of the stabilizing layer 88 is about 5 to 10 μm.
[0034]
  In the oxide superconducting conductor manufacturing apparatus of the embodiment, in particular, a pair of opposing side walls 41, 41 provided along the longitudinal direction of the base material 38 of the tape fed into the reactor 31, and a tape shape Provided in a direction crossing the longitudinal direction of the substrate 38,A gas diffusion member 45 having a front wall 42 and a rear wall 43 that connect the pair of side walls 41 and 41 to each other, and the distance between the front wall 42 and the rear wall 43 becomes wider toward the reactor 31, and a slit 54a. The gas diffusion part 40 having the slit nozzle 54 provided in the direction intersecting the longitudinal direction of the tape-like base material 38 moving in the reactor 31 is provided. When the raw material gas is sent from the gas diffusion member 45 to the gas diffusion member 45, the diffusion of the raw material gas in the direction parallel to the length direction of the tape-like base material 38 fed into the reactor 31 is promoted. The diffusion of the raw material gas in the direction orthogonal to the length direction can be suppressed. As a result, when the tape-shaped substrate 38 is fed into the reactor 31, the tape-shaped substrate 38 is fed so that one end surface 38 b in the width direction of the tape-shaped substrate 38 faces the slit 54 a of the slit nozzle 54. Since the superconducting layer forming surfaces 38a on both sides of the substrate 38 are parallel to the flow of the source gas from the slit nozzle 54, the source gas reacts on both sides of the heated tape-like substrate 38 and reacts. An oxide superconducting layer 87 can be formed by efficiently depositing the product on both conductive layer forming surfaces 38a.
[0035]
Therefore, according to the oxide superconducting conductor manufacturing apparatus of the embodiment, the oxide superconducting layer 87 can be formed on both surfaces of the tape-like base material 38 at a time, so that one side of the oxide superconducting material is formed on the tape-like base material 38. It is not necessary to form a layer, and an oxide superconducting conductor 85 having substantially the same superconducting characteristics of the oxide superconducting layer 87 on both sides can be manufactured. The oxide superconducting conductor 85 is formed on both sides of the tape-like substrate 38. Since the oxide superconducting layer 87 is provided, a critical current approximately twice as high as that of a conventional oxide superconducting conductor in which an oxide superconducting layer is formed only on one side of a tape-like substrate can be obtained.
[0036]
Moreover, according to the manufacturing method of the oxide superconducting conductor of the embodiment, when the oxide superconducting conductor is manufactured using the manufacturing apparatus of the oxide superconducting conductor of the embodiment, the tape-like base material 38 is formed on both surfaces of the superconducting conductor 38. By feeding into the reactor 31 so that the layer forming surface 38a is parallel to the flow of the raw material gas from the slit nozzle 54, the raw material gas reacts on both sides of the heated tape-like substrate 38 and reacts. Since the product can be efficiently deposited on the conductive layer forming surfaces 38a on both sides, the oxide superconducting layer 87 can be formed on both sides of the tape-like substrate 38 at a time.
In addition, the oxide superconducting conductor 85 obtained by the oxide superconducting conductor manufacturing method of the embodiment has the oxide superconducting layer 87 on both surfaces of the tape-like base material 38 via the polycrystalline intermediate layer 86. In addition, since the superconducting layers 87 on both sides have substantially the same superconducting characteristics, the oxide superconducting layer is formed on only one side of the tape-like base material, which is about twice as much as the conventional oxide superconducting conductor. High critical current can be obtained.
[0037]
【Example】
EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not limited only to these Examples.
(Example)
A quartz CVD reactor 30 having the structure shown in FIGS. 2 to 5 is incorporated into the oxide superconducting conductor manufacturing apparatus shown in FIG. 1 to form a Y—Ba—Cu—O-based oxide superconducting conductor below. It produced as follows.
As a raw material solution, Y (thd)_Three, Ba (thd)₂, Cu (thd)₂In a molar ratio of Y: Ba: Cu = 1.0: 2.4: 3.3, dissolved in a tetrahydrofuran solution, and stored in a storage container.
This raw material solution was continuously supplied to the raw material solution supply part of the liquid raw material supply apparatus by a pressurized liquid pump (pressure source) at a flow rate of 0.25 ml / min. At the same time, Ar was sent as an atomizing gas to the atomizing gas supply section at a flow rate of about 300 ccm and Ar as a shielding gas was sent into the shielding gas supply section at a flow rate of about 100 ccm. Through the above operation, a certain amount of mist-like liquid material is continuously supplied into the vaporizer, and further, the material gas vaporized from the liquid material is supplied.
A certain amount was continuously supplied to the gas diffusion member of the CVD reactor through the gas introduction pipe. The temperature of the vaporizer and the transport pipe at this time was 230 ° C.
[0038]
The substrate moving speed in the reactor is set to 1.0 m / h, the substrate heating temperature is 800 ° C., the reactor pressure is set to 5 torr, and Y-Ba-Cu having a thickness of 0.6 to 0.7 μm on both surfaces of the substrate. A -O-based oxide superconducting layer was continuously formed to obtain a tape-shaped oxide superconducting conductor. Here, when feeding the substrate into the reactor, the both surfaces of the substrate are slit by feeding so that one end surface in the width direction of the substrate faces the slit of the slit nozzle provided at the tip of the gas introduction pipe. It was sent so as to be parallel to the flow of the raw material gas from the nozzle. As the base material here, a YSZ (yttrium-stabilized zirconia) in-plane oriented intermediate layer (orientation controlled polycrystalline intermediate layer) is formed on both surfaces by ion beam assisted sputtering on a Hastelloy tape (width 1 cm × length). ˜30 cm × thickness 0.02 cm) was used.
[0039]
(Comparative example)
The shape of the gas diffusion member of the gas diffusion part is a truncated pyramid (the distance between the pair of side walls becomes wider as the distance from the reactor approaches, and the distance between the front wall and the rear wall connecting the pair of side walls to each other is also in the reactor. And the width of the slit nozzle provided at the tip of the gas introduction tube is wider in the direction crossing the longitudinal direction of the substrate moving in the reactor. When the substrate is fed into the reactor using an apparatus in which the same CVD reactor as that used in the above is incorporated in the oxide superconductor manufacturing apparatus, the superconducting layer forming surface of the substrate faces the slit of the slit nozzle. The oxide superconducting layer was formed on one surface of the substrate. Subsequently, an oxide superconducting layer was formed in the same manner on the other surface of the substrate using the same apparatus, thereby obtaining a tape-shaped oxide superconducting conductor.
[0040]
The tape-shaped oxide superconducting conductors obtained in Examples and Comparative Examples were subjected to Ag coating using a sputtering apparatus, and after the Ag coating, heat treatment was performed at 500 ° C. for 2 hours in a pure oxygen atmosphere to obtain a measurement sample.
These samples were cooled to 77 K with liquid nitrogen, and the critical currents (Ic) of the oxide superconducting layers on both surfaces of the base material in each sample were measured under the condition of an external magnetic field of 0 T (Tesla). As a result, the critical current of one oxide superconducting layer of the tape-shaped oxide superconducting conductor obtained in the comparative example is 2.1 A, and the critical current of the other oxide superconducting layer is 9.5 A. The superconducting properties of the oxide superconducting layer were significantly different, and a critical current of 11.6 A was obtained as the oxide superconducting conductor. On the other hand, the critical current of one oxide superconducting layer of the tape-shaped oxide superconducting conductor obtained in the example is 10.0 A, and the critical current of the other oxide superconducting layer is 10.3 A. Compared with the oxide superconductor obtained in the comparative example, the superconducting characteristics of the oxide superconducting layers on both sides are substantially equal, and the oxide superconducting conductor has a critical current of 20.3 A, which is about 2 of that in the comparative example. It was found that double the critical current was obtained.
[0041]
【The invention's effect】
As described above, according to the oxide superconducting conductor manufacturing apparatus of the present invention, in particular, a pair of opposing side walls provided along the longitudinal direction of the base material of the tape fed into the reactor, and the tape Provided in a direction intersecting with the longitudinal direction of the substrate, and having a front wall and a rear wall connecting the pair of side walls to each other, and the distance between the front wall and the rear wall becomes wider as the reactor is approached. A gas diffusion member in which the distance between the pair of side walls is a fixed size that is narrower than the distance between the front wall and the rear wall; and a tape-shaped substrate whose long side of the slit is moving in the reactor When the raw material gas is sent from the slit nozzle to the gas diffusion member by being provided with the gas diffusion part having the slit nozzle provided in the direction intersecting with the longitudinal direction of the gas, it was sent into the reactor Since the diffusion of the source gas in the direction parallel to the length direction of the loop-shaped substrate is promoted, the diffusion of the source gas in the direction perpendicular to the length direction of the tape-shaped substrate can be suppressed. When the tape-shaped substrate is fed into the reactor, the superconducting layer forming surfaces on both sides of the tape-shaped substrate are fed in parallel to the flow of the raw material gas from the slit nozzle, thereby heating the tape-shaped substrate. The source gas reacts on both sides of the base material, and the reaction product can be efficiently deposited on the conductive layer forming surfaces on both sides to form an oxide superconducting layer.
Therefore, according to the oxide superconducting conductor manufacturing apparatus of the present invention, an oxide superconducting layer can be formed on both surfaces of a tape-shaped substrate at one time, so that the superconducting properties of the oxide superconducting layers on both sides are substantially equal. A superconducting conductor can be manufactured, and the oxide superconducting conductor has an oxide superconducting layer on both sides of the tape-like substrate, so that an oxide superconducting layer is formed only on one side of the tape-like substrate. A higher critical current can be obtained than the conventional oxide superconducting conductor.
[0042]
Moreover, according to the manufacturing method of the oxide superconducting conductor of the present invention, the superconducting layer forming surface on both sides of the tape-shaped base material is the raw material from the slit nozzle using the oxide superconducting conductor manufacturing apparatus of the present invention. It is fed into the reactor so as to be parallel to the gas flow, the raw material gas of the oxide superconductor is supplied from the raw material gas supply source into the reactor through the gas diffusion section, and the tape-shaped substrate is further supplied. By performing the CVD reaction while heating and depositing the reaction product on both sides of the substrate, the raw material gas reacts on both sides of the heated tape-like substrate and the reaction product is converted into the conductive layer on both sides. Since it can be efficiently deposited on the formation surface, an oxide superconducting layer can be formed on both surfaces of the tape-like substrate at once.
Moreover, the oxide superconducting conductor obtained by the method for producing an oxide superconducting conductor of the present invention has an oxide superconducting layer on both sides of a tape-like substrate, and the oxide superconducting layers on both sides are Since the superconducting characteristics are substantially equal, a higher critical current can be obtained compared to a conventional oxide superconducting conductor in which an oxide superconducting layer is formed only on one side of a tape-like substrate.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an overall configuration of an oxide superconducting conductor manufacturing apparatus according to an embodiment of the present invention.
2 is a schematic diagram showing a structural example of a CVD reactor provided in the apparatus for manufacturing an oxide superconducting conductor in FIG.
3 is a cross-sectional view showing a detailed structure in a direction along a length direction of a tape-like base material fed into the CVD reactor shown in FIG. 2;
4 is a cross-sectional view showing a detailed structure in a direction (thickness direction of the tape-shaped substrate) perpendicular to the length direction of the tape-shaped substrate fed into the CVD reactor shown in FIG. 2;
5 is a plan view showing a detailed structure of the CVD reactor shown in FIG.
6 is a sectional view taken along line II of the slit nozzle of the CVD reactor shown in FIG. 3;
FIG. 7 is a cross-sectional view showing one embodiment of an oxide superconducting conductor obtained by the method for producing an oxide superconducting conductor of the present invention.
FIG. 8 is a cross-sectional view showing a conventional oxide superconducting conductor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 31 ... Reactor, 38 ... Tape-shaped base material, 38a ... Superconducting layer formation surface, 38b ... End surface of the width direction, 40 ... Gas diffusion part, 41 ... Side wall, 42 ... Front wall 43 ... rear wall 45 ... gas diffusion member 53 ... gas introduction pipe 54 ... slit nozzle 54a ... slit 54b ... short side 54c ... long side 85 ... oxide superconducting conductor, 86 ... polycrystalline intermediate layer, 87 ... oxide superconducting layer, 88 ... stabilization layer.

Claims (3)

During the movement of the tape-shaped substrate fed into the inside, a reactor for performing a CVD reaction in which the raw material gas of the oxide superconductor is chemically reacted on both sides to form an oxide superconducting layer, and a raw material gas supply source A gas diffusion section connected to supply the source gas into the reactor is provided,
The gas diffusion part is provided at a gas diffusion member attached to the reactor, a gas introduction pipe connected to the gas diffusion member and supplying the source gas to the gas diffusion member, and a tip of the gas introduction pipe The gas diffusion member comprises a pair of opposing side walls provided along the longitudinal direction of the base material of the tape fed into the reactor. And a front wall and a rear wall that are provided in a direction intersecting with the longitudinal direction of the tape-like base material and connect the pair of side walls to each other, and the distance between the front wall and the rear wall approaches the reactor. The distance between the pair of side walls is a constant size that is narrower than the distance between the front wall and the rear wall;
The apparatus for producing an oxide superconducting conductor, wherein the slit of the slit nozzle has a long side provided in a direction intersecting with a longitudinal direction of a tape-like substrate moving in the reactor. Using the manufacturing apparatus of the oxide superconductor of claim 1 Symbol placement, the reactor as a superconducting layer formed surface of the double-sided tape-like base material of which is parallel to the flow of feed gas from the slit nozzle The raw material gas of the oxide superconductor is supplied from the raw material gas supply source through the gas diffusion section into the reactor, and the tape-shaped base material is further heated so that the reaction product is placed on both sides of the base material. A method for producing an oxide superconducting conductor, wherein a CVD reaction is performed while being deposited on the substrate. 3. The method for producing an oxide superconducting conductor according to claim 2, wherein the tape-shaped base material has a polycrystalline intermediate layer formed on both sides.

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