JP2007073314A - Nb3Al COMPOUND BASED SUPERCONDUCTING WIRE, AND ITS MANUFACTURING METHOD AND DEVICE OF MANUFACTURING THE SAME - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing an Nb<SB>3</SB>Al compound based superconducting wire capable of applying quick heating and quick cooling to longitudinal wire material with uniform condition, and to provide the Nb<SB>3</SB>Al compound based superconducting wire manufactured by the above manufacturing method, and a manufacturing device used for the above manufacturing method. <P>SOLUTION: An Nb-Al super-saturable solid solution is generated by quickly cooling it by making a multi-wire material 12 pass through cooling liquid Ga27 after applying quick heating treatment to the multi-wire material 12 containing Nb (Nb alloy) and Al (Al alloy) by joule heat generation of the wire material. Afterwards, a compound phase of Nb<SB>3</SB>Al is deposited by heating it again. On the manufacturing method of the Nb<SB>3</SB>Al compound based superconducting wire using a rapid heating and quenching transformation method, as a treatment for making the length of a joule heat generating section constant during production, the height of the surface of the liquid Ga27 is measured by a liquid face sensor 34 so as to control the height of surface of the liquid Ga27 constant, and the liquid Ga is injected from a Ga injection port 35. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a Nb ₃ Al compound-based superconducting wire, a manufacturing method thereof, and a manufacturing apparatus thereof, and more particularly, to a Nb ₃ Al compound-based superconducting wire having a long wire length, a manufacturing method thereof, and a manufacturing apparatus thereof.

Nb ₃ Al compound-based superconducting wires have superior critical current density characteristics in a high magnetic field compared to alloy-based / compound-based superconducting wires such as NbTi and Nb ₃ Sn. It is expected to be put to practical use as a superconducting material such as high energy particle accelerators and fusion reactor magnets.

Conventionally, as a method of manufacturing a Nb ₃ Al compound-based superconducting wire, for example, Nb and Al are combined at a predetermined composition ratio and heated to a temperature of 600 to 1050 ° C. with a mutual diffusion distance shortened to about several tens of nm. A manufacturing method called a diffusion method in which an Nb ₃ Al compound is generated by a solid phase diffusion reaction is known.

However, according to this production method, the Nb ₃ Al phase that is stable (can be single-phased) only at a high temperature of about 1300 ° C. or more in the stoichiometric composition is in a shortage of temperature (unstable temperature). Region)). For this reason, deviation from the stoichiometric composition may occur, or a mixed phase with phases having different composition ratios may occur. As a result, it is difficult to obtain a high critical current density. For example, it is almost impossible to deal with an NMR magnet or the like that needs to satisfy required characteristics in a high magnetic field of 20 T or more by a diffusion method.

On the other hand, as another manufacturing method for obtaining a Nb ₃ Al compound-based superconducting wire, Nb and Al are combined at a predetermined composition ratio, and this is rapidly heated to a temperature of 1500 ° C. or higher and immediately cooled, thereby Nb A production method called a rapid heating / quenching / transformation method in which an Nb ₃ Al compound phase is precipitated by producing an -Al supersaturated solid solution and then reheating it is known (for example, see Patent Document 1).

In this manufacturing method, since the heating temperature is high, there is no deviation from the stoichiometric composition or reduction of the critical current density due to the mixed phase, and it is possible to manufacture a superconducting wire having a high critical current density. It is regarded as a promising manufacturing method that can meet the demand. In other words, the rapid heating / quenching / transformation method can be said to be the only manufacturing method at present when considering application to an Nb ₃ Al compound-based superconducting wire NMR magnet or the like.

Usually, the superconducting wire is manufactured by the rapid heating / quenching / transformation method according to the following procedure. First, an Nb and Al sheet is prepared and laminated and wound, and then this is covered with an Nb pipe to produce a single wire. Next, a plurality of the obtained single wires are covered again with an Nb pipe, and this is subjected to wire drawing and the like to obtain a multi-composite wire of Nb and Al, which is then heated to 1500 ° C. by Joule heat generation by continuous energization. Heat to above high temperature and cool immediately. After the Nb-Al supersaturated solid solution is formed in the Nb and Al laminated parts by this rapid heating and rapid cooling, it is further heated again at a temperature of 600 to 1050 ° C., thereby precipitating Nb ₃ Al to form a superconducting wire It is.

  FIG. 13 is a schematic configuration diagram of a conventional manufacturing apparatus (rapid heating / quenching apparatus) used for manufacturing a superconducting wire by a rapid heating / quenching / transformation method. The rapid heating and quenching device 20 includes a feed reel 21 that sends out the multi-wire 12, a current-carrying capstan 22 that receives the multi-wire 12 from the reel 21, a DC power source 23 that rapidly heats the multi-wire 12, and a current-carrying capstan 22. The reel 24 that receives the multi-wire material 12 from the reel 24, the take-up reel 25 that receives the multi-wire material 12 from the reel 24, the cooling container 26 in which the reel 24 is housed (arranged inside), and the cooling container 26. In addition, the multi-wire material 12 is roughly constituted by a cooling metal material 27 for rapidly cooling the multi-wire material 12.

In order to generate an Nb—Al supersaturated solid solution in the wire rod in such a rapid heating / cooling device 20, first, the multi-wire material 12 is sent out and wound around the reel 21, and one end is sent out from the reel 21 to the energized capstan 22, the reel. 24 is wound around the take-up reel 25. Next, the take-up reel 25 is rotated at a predetermined speed to take up the multi wire 12. Then, the multi wire 12 delivered from the delivery reel 21 is continuously energized and heated by the DC power source 23 between the energized capstan 22 and the liquid surface of the cooling metal material 27 (joule heat generation), and then cooled. The metal material 27 is rapidly cooled and taken up by the take-up reel 25.
JP 2004-356046 A

However, the conventional rapid heating / quenching / transformation method has the following problems. That is, in order to apply the Nb ₃ Al wire to an NMR magnet or the like, a km-class wire length having a homogeneous characteristic is required. For such a long wire, the Nb ₃ Al wire is subjected to rapid thermal quenching treatment. Since the metal material for cooling and the compound of Nb or Nb alloy and the metal material for cooling adhere to the surface of the wire that has been subjected to the rapid heating and quenching treatment, cooling is performed as the rapid heating and quenching treatment length increases. The cooling metal in the container is reduced. If the metal material for cooling, which also serves as an electrode during rapid heating, decreases, the length of the current heating section (the length of the Joule heating section of the wire) increases and the processing conditions change, so the maximum temperature reached during rapid heating is There is a problem that it becomes high and it becomes difficult to produce a long wire homogeneous in the longitudinal direction of the wire.

Accordingly, an object of the present invention, uniform method for manufacturing a rapid heating and quenching treatment capable Nb 3 _Al compound superconducting wire long wire in condition, Nb 3 _Al compound superconducting wire manufactured using this manufacturing method, And it is providing the manufacturing apparatus used for this manufacturing method.

In order to achieve the above object, the present invention rapidly heats a wire containing Nb or Nb alloy and Al or Al alloy by Joule heat generation of the wire, and then rapidly passes the wire through a cooling liquid metal material. A method for producing a Nb ₃ Al compound-based superconducting wire using a rapid heating / quenching / transformation method in which a Nb—Al supersaturated solid solution is generated by cooling treatment, and then an Nb ₃ Al compound phase is precipitated by reheating. The Nb ₃ Al compound is characterized in that the treatment for making the liquid surface height of the cooling liquid metal material constant is performed as a treatment for making the Joule heat generation section length constant during manufacture. A method of manufacturing a system superconducting wire is provided.

In order to achieve the above object, according to the present invention, a wire containing Nb or Nb alloy and Al or Al alloy is rapidly heated by Joule heat generation of the wire, and then the wire is passed through the cooling liquid metal material. Production of Nb ₃ Al compound-based superconducting wire using a rapid thermal quenching / transformation method in which an Nb—Al supersaturated solid solution is formed by rapid cooling treatment and then an Nb ₃ Al compound phase is precipitated by reheating. A method for producing an Nb ₃ Al compound-based superconducting wire, wherein when the cooling treatment is performed, the wire is fed by a plurality of reels entirely embedded in the cooling liquid metal material Provide a method.

Further, the present invention in order to achieve the above object, provides a Nb 3 _Al compound superconducting wire which is characterized by being manufactured by the manufacturing method of the Nb 3 _Al compound superconducting wire of the present invention described above.

In order to achieve the above object, the present invention provides a feed reel for feeding a wire containing Nb or Nb alloy and Al or Al alloy, a heating means for rapidly heating the wire, and a cooling liquid metal for rapidly cooling the wire. An apparatus for manufacturing an Nb ₃ Al compound superconducting wire, comprising a cooling container for containing a material, a reel for feeding the wire provided in the cooling container, and a take-up reel for winding the wire. Nb ₃ Al, further comprising an injection port for injecting the cooling liquid metal material in accordance with the liquid level of the cooling liquid metal material in order to make the Joule heating section length in the inside constant An apparatus for manufacturing a compound superconducting wire is provided.

In order to achieve the above object, the present invention provides a feed reel for feeding a wire containing Nb or Nb alloy and Al or Al alloy, a heating means for rapidly heating the wire, and a cooling liquid metal for rapidly cooling the wire. An apparatus for producing an Nb ₃ Al compound-based superconducting wire, comprising: a cooling container that contains a material; a reel that feeds the wire provided in the cooling container; and a take-up reel that winds the wire. Nb ₃ further comprising a substance having a surface that does not substantially cause a chemical reaction with the metal material submerged in the cooling liquid metal material according to a liquid level of the liquid metal material for cooling. An apparatus for producing an Al compound-based superconducting wire is provided.

In order to achieve the above object, the present invention provides a feed reel for feeding a wire containing Nb or Nb alloy and Al or Al alloy, a heating means for rapidly heating the wire, and a cooling liquid metal for rapidly cooling the wire. An apparatus for manufacturing an Nb ₃ Al compound superconducting wire, comprising a cooling container for containing a material, a reel for feeding the wire provided in the cooling container, and a take-up reel for winding the wire. Nb ₃ Al compound further comprising a control mechanism for moving the cooling container up and down according to the liquid level of the cooling liquid metal material in order to make the Joule heat generation section length in the inside constant A superconducting wire manufacturing apparatus is provided.

According to the present invention, an Nb ₃ Al compound-based superconducting wire capable of rapid heating and quenching of a long wire under uniform conditions and having a stable (homogeneous) critical current density characteristic in the longitudinal direction of the wire is manufactured. Is possible.

Hereinafter, a method for manufacturing a Nb 3 _Al compound superconducting wire according to an embodiment of the present invention.
FIG. 1 shows the shape of a wire in each manufacturing process in the present embodiment.

  FIG. 1A shows a cross-sectional structure of the composite strand 7. The composite strand 7 is formed by laminating an Nb sheet 2 and an Al sheet 3 and winding the core sheet 4 around the central member 4 without any gaps on the jelly roll type laminate 1 to form an Nb matrix. 5 and a Cu coating 6 is formed on the Nb coating 5. Here, for example, Nb is used as the central member 4.

  FIG. 1 (b) shows a single wire 8. This single wire 8 can be produced by reducing the surface of the composite wire 7 to a hexagonal cross section by hydrostatic extrusion and die drawing, and then removing the Cu coating 6. This single wire 8 has a structure capable of being closely assembled by a hexagon.

  FIG. 1 (c) shows the composite wire 11. This composite wire 11 can be obtained by forming an Nb tube 9 and a Cu—Ni alloy tube 10 to be an external matrix on a bundle of single wires 8 by hydrostatic pressure extrusion. The composite wire 11 is subjected to surface reduction processing to a predetermined size by die drawing, and then the outermost Cu-Ni alloy tube 10 is removed to obtain a multi-wire 12 having a predetermined size.

  FIG. 1D shows a cross-sectional structure of the multi-wire 12 obtained by the above steps. In the figure, 9 'indicates an external matrix constituting the outer layer portion of the multi-wire material 12. The multi wire 12 may be either a round wire or a flat wire as shown in the figure.

The multi-wire 12 is rapidly heated to a predetermined temperature (for example, about 1500 to 2000 ° C.) using a rapid heating / quenching device to be described later, and this is immersed in, for example, liquid gallium (Ga) and rapidly cooled. after generating the Nb-Al supersaturated solid solution in the portion of laminate 1 of the wire 8, a predetermined temperature (e.g., about 600 to 1050 ° C.) _Nb to precipitate _Nb 3 Al compound phase by reheating 3 Al A compound superconducting wire is manufactured.

  As a means for rapid heating, a method of heating the multi wire 12 by self-heating (Joule heat generation) due to Joule loss is suitable, and an energization heating method in which a current is directly supplied to the multi wire 12 is adopted. On the other hand, in consideration of continuous rapid cooling (rapid cooling) of the multi-wire 12 heated to a high temperature, as a rapid cooling means, it is continuously immersed in a liquid having a high boiling point or decomposition temperature (for example, liquid Ga). The method is preferred.

The superconducting characteristics of superconducting wires are greatly affected by the maximum temperature of the wire during Joule heating, but the maximum temperature varies depending on the amount of electricity supplied to the wire (energization time x current value). It is necessary to. It is defined by “energization time = energization distance / transmission speed”. Since the energization current value is controlled by the power source and the line speed is controlled by the rotation speed of the energization capstan motor, these are considered to be constant. That is, it is important how to keep the energization distance (distance from the energization capstan to the liquid Ga liquid surface, the Joule heat generation section length) constant. However, the rapidly cooled multi-wire 12 goes out of the cooling vessel containing liquid Ga in a state where Ga and a compound of Ga and the outer peripheral matrix 9 ′ are adhered to the surface thereof, so that the cooling process proceeds. As a result, the liquid Ga in the cooling container may decrease. Here, since the energizing capstan rotates but does not move, the fluctuation of the liquid Ga level may be controlled in order to keep the Joule heat generation section length constant. As a main factor of the liquid level fluctuation of the liquid Ga,
(1) The rise of the liquid level due to the temperature increase of the liquid Ga during the passage into the liquid Ga for the purpose of cooling the heating wire (2) The fluctuation of the Ga liquid level due to the passage (3) For example, the adhesion of Ga to the wire and the decrease of the liquid level due to the decrease of the liquid Ga in the cooling container may be mentioned.

  FIG. 2 summarizes the manufacturing process of the superconducting wire described above in a flowchart, and FIGS. 2 (a) to (d) correspond to FIGS. 1 (a) to (d), respectively.

[First Embodiment]
FIG. 3 is a schematic configuration diagram of the manufacturing apparatus (rapid heating / cooling apparatus) according to the first embodiment of the present invention. The rapid heating and quenching device 30 is arranged inside the first casing 31A in a vacuum state (for example, 5 × 10 ⁻⁵ Torr), and sends out the multi-wire 12 and the multi-wire 12 from the reel 21 and the reel 21. Receiving the energizing capstan 22 for energizing, the DC power source 23 for rapidly heating the multi wire 12 (joule heating), the reel 24 receiving the multi wire 12 from the energizing capstan 22, and receiving the multi wire 12 from the reel 24. A take-up reel 25 for winding, a cooling container 26 in which the reel 24 is accommodated, a cooling metal material (for example, liquid Ga27) for rapidly cooling the multi-wire material 12 placed in the cooling container 26, and a first The adjustment container 32 communicated with the cooling container 26 disposed inside the second casing 31B outside the casing 31A, and for cooling in the adjustment container 32 Controlled by a metal material (for example, liquid Ga33), a liquid level sensor 34 for measuring the liquid level of the liquid Ga33, and a control mechanism (not shown) so as to keep the liquid level constant according to the change in the liquid level. And a Ga injection port 35 for injecting liquid Ga33 into the adjustment container 32. The Ga injection port 35 is installed on the side wall or the like of the second housing 31B and communicates with the outside of the housing 31B.

  The rapid heating and quenching device 30 has substantially the same configuration as that of the conventional rapid heating and quenching device 20, but the cooling vessel is adjusted by adjusting the liquid level of the liquid Ga 33 in the adjustment vessel 32 to be constant. 26 is greatly different in that it has the above-described mechanism capable of keeping the liquid level of the liquid Ga27 in the liquid 26 constant.

  As the cooling metal material, gallium (Ga) is most suitable because of its high conductivity, high boiling point, and low melting point.

The inside of the second housing 31B is in a vacuum state, for example, 5 × 10 ⁻⁵ Torr. The insides of the first casing 31A and the second casing 31B are preferably in a vacuum state having an equivalent degree of vacuum. If the degree of vacuum in the two housings is significantly different, either the cooling container 26 in the first housing 31A or the adjustment container 32 in the second housing 31B or the inside of the second housing 31B Is the atmospheric air, the cooling metal material is sucked from the adjustment container 32 in the second casing 31B to the cooling container 26 side in the first casing 31A, and the liquid level height is accurate. Measurement becomes difficult.

  The liquid level sensor 34 may be configured to use a sensor that can be used in a vacuum inside the second casing 31B. However, the sensor that can be used at atmospheric pressure is disposed outside the second casing 31B. Is desirable. Further, when the liquid Ga33 is injected from the Ga injection port 35, it is desirable that the liquid surface of the liquid Ga33 in the adjustment container 32 is not shaken as much as possible.

[Second Embodiment]
FIG. 4 is a schematic configuration diagram of a manufacturing apparatus (rapid heating / cooling apparatus) according to the second embodiment of the present invention. The rapid heating and quenching device 40 has the same configuration as the rapid heating and quenching device 30, but differs in an adjustment mechanism (method) for keeping the liquid level constant.

  The rapid heating and quenching apparatus 40 is not shown so as to keep the liquid level constant according to the change in the liquid level measured by the liquid level sensor 34 instead of the Ga injection port 35 in the rapid heating and quenching apparatus 30. A raising jig 36 is provided which is controlled by the control mechanism and is taken in and out of the liquid Ga 33 in the adjustment container 32. Thereby, the liquid level height of the liquid Ga27 in the cooling container 26 can be kept constant. When the raising jig 36 is taken in and out of the liquid Ga33 in the adjustment container 32, it is desirable to prevent the liquid surface of the liquid Ga33 from shaking as much as possible.

  The raising jig 36 may be a substance having a surface that does not substantially cause a chemical reaction with the cooling metal material. For example, a substance coated with alumina is preferably used. Alumina is chemically stable even at high temperatures, so it is effective as a surface treatment that does not cause a chemical reaction with the metal material for cooling even when the metal material for cooling becomes high temperature by rapid heating / cooling treatment. .

[Third Embodiment]
FIG. 5 is a schematic configuration diagram of a manufacturing apparatus (rapid heating / cooling apparatus) according to a third embodiment of the present invention. The rapid heating and quenching device 50 is disposed inside a casing 31 that is in a vacuum state (for example, 5 × 10 ⁻⁵ Torr), and is supplied with a feeding reel 21 that sends out the multi-wire 12, and energization that receives the multi-wire 12 from the reel 21. Current-carrying capstan 22, DC power source 23 for rapidly heating multi-wire material 12, reel 24 receiving multi-wire material 12 from current-carrying capstan 22, take-up reel 25 receiving multi-wire material 12 from reel 24, and reel 24 is a horizontally long cooling container 26 in the figure, a cooling metal material (for example, liquid Ga27) for rapidly cooling the multi wire 12 placed in the cooling container 26, and a horizontally long cooling in the figure A liquid level sensor 34 that measures the liquid level of the liquid Ga 27 at a position away from the reel 24 in the container 26, and keeps the liquid level constant according to changes in the liquid level. Thus, it is schematically constituted by a Ga injection port 35 that is controlled by a control mechanism (not shown) and injects liquid Ga 27 into the adjustment container 32. The Ga injection port 35 is installed on the side wall of the housing 31 and communicates with the outside of the housing 31. The cooling container 26 may have a longer vertical or horizontal width, but a part of the vertical or horizontal width may protrude. The liquid level height of the protruded portion is measured, and liquid Ga27 is injected there from the Ga injection port 35 according to the changed liquid level height.

  The liquid level sensor 34 may be configured to use a sensor that can be used in a vacuum inside the casing 31, but is preferably configured to have a sensor that can be used under atmospheric pressure outside the casing 31. Further, when the liquid Ga27 is injected from the Ga injection port 35, it is desirable to prevent the liquid surface from shaking as much as possible.

[Fourth Embodiment]
FIG. 6 is a schematic configuration diagram of a manufacturing apparatus (rapid heating / cooling apparatus) according to a fourth embodiment of the present invention. The rapid heating and quenching device 60 has the same configuration as the rapid heating and quenching device 50, but differs in an adjustment mechanism (method) for keeping the liquid level constant. It has the same configuration.

  The rapid heating and quenching device 60 is not shown so as to keep the liquid level constant according to the change in the liquid level measured by the liquid level sensor 34 instead of the Ga injection port 35 in the rapid heating and quenching device 50. A raising jig 36 is provided that is controlled by the control mechanism and is taken in and out of the liquid Ga 27 in the cooling container 26. When the raising jig 36 is taken in and out of the liquid Ga27 in the cooling container 26, it is desirable to prevent the liquid surface of the liquid Ga27 from shaking as much as possible.

[Fifth Embodiment]
FIG. 7 is a schematic diagram showing a configuration of a reel accommodated in a cooling container, (a) relates to a conventional rapid heating and quenching apparatus, and (b) is a fifth embodiment of the present invention. The present invention relates to a rapid heating and quenching apparatus according to the embodiment.

  Since the reel 24A according to the conventional rapid heating / cooling device rotates in accordance with the operation of the wire 12 when the multi-wire 12 is wound by the take-up reel 25, the liquid surface of the liquid Ga27 undulates and the liquid surface shakes (vibrates). ) Is likely to occur. For this reason, a change may occur in the distance between the energizing capstan 22 and the liquid surface of the liquid Ga 27, that is, the energizing distance.

  On the other hand, the reel 24B according to the rapid heating and quenching apparatus according to the fifth embodiment of the present invention is fixed and does not rotate, and a plurality of small reels 24b provided along the circumference of the reel 24B are wound. The multi-wire 12 is rotated when the multi-wire 12 is taken up by the take-up reel 25, and since the entire small reel 24b is buried in the liquid Ga27, even if it rotates, the Ga liquid level does not generate a vibration (vibration). Or it is hard to generate.

  The plurality of small reels 24b are provided, for example, at least at a portion in contact with the multi wire 12 along the circumference of the reel 24B at intervals of about 15 ° (about 10 to 20 °) of the central angle of the reel 24B. The method of attaching the small reel 24b to the reel 24B is not particularly limited, but a small hole is provided at each attachment position of the small reel 24b along the circumference of the two disks constituting the reel 24B. The small reel 24b can be attached using a small hole.

  When the size of the reel 24B is about 120 mm, it is desirable to use a small reel 24b having a diameter of about 5 to 15 mm (about 1/24 to 1/8). Further, the material of the small reel 24b is not required to substantially chemically react with the liquid Ga, and alumina, stainless steel, or the like can be used.

[Sixth Embodiment]
FIG. 8 is a partially enlarged schematic view of the rapid heating and quenching apparatus according to the sixth embodiment of the present invention. The rapid heating and quenching apparatus according to the sixth embodiment includes a sensor head 37 provided above the liquid Ga27 liquid level and the liquid Ga27 liquid level directly below the sensor head 37 for measuring the liquid Ga27 liquid level height. A liquid level sensor that can be used in a vacuum made of a special metal 38 (object to be measured) that is floated on the surface is provided, and a control mechanism (not shown) is used to keep the liquid level constant according to changes in the liquid level. Controlled, the cooling container 26 is moved up and down by an operating mechanism (not shown). The configuration of the reel 24B accommodated in the cooling container 26 is the same as that of the rapid heating and quenching device according to the fifth embodiment described above.

  The operation mechanism preferably includes a mechanism for minimizing the fluctuation of the liquid Ga 27 when the cooling container 26 is moved up and down. Moreover, the structure which can be operated manually from the exterior of the housing | casing (vacuum container) of a rapid thermal quenching apparatus may be sufficient as the said operation mechanism.

  The liquid level sensor may be configured such that a sensor that can be used under atmospheric pressure is arranged outside the casing as shown in FIG. 3 instead of the liquid level sensor that can be used in the vacuum.

  Further, the reel accommodated in the cooling container 26 may be a conventional rotating reel 24A as shown in FIG. 7A. However, since the energization distance may change, as shown in FIG. It is desirable to use a non-rotating reel 24B provided with a plurality of small reels 24b. Similarly, in the first to fourth embodiments, it is desirable to use a non-rotating reel 24B provided with a plurality of small reels 24b.

[Modification]
In the above embodiment, the distance to the liquid level is measured using the liquid level sensor provided above the liquid level, but the object to be measured is floated on the liquid Ga, and the height from the side is measured. It is also possible to apply a method of knowing the liquid level by monitoring the fluctuation of the liquid level.

  Further, the multi-wire material 12 that has passed through the cooling container 26 is sandwiched between sheets of Teflon (registered trademark) (substance name: polytetrafluoroethylene) or silicone resin (substance name: polydimethylsiloxane). ) Or a silicone resin sheet is passed through a jig, and the liquid Ga adhering to the surface of the multi-wire material is wiped, and this is returned to the cooling container 26 to simplify the liquid level. Although a method for suppressing the decrease in height can also be adopted, this method cannot completely wipe the liquid Ga and cannot eliminate the change in the liquid level, so it is used in combination with the first to sixth embodiments. It is desirable to do.

[Effect of the embodiment]
(1) By maintaining the liquid level height of the liquid Ga in the cooling container constant, the energization distance (joule heating section length) between the energizing capstan and the liquid Ga liquid level is made constant, and uniform conditions This makes it possible to rapidly heat and cool long wires.

(2) By fixing the reel accommodated in the cooling container and providing a plurality of small reels that rotate along the circumference of the reel, the fluctuation (vibration) of the liquid Ga liquid surface can be reduced. Therefore, the energizing distance (joule heat generation section length) between the energizing capstan and the liquid Ga liquid surface is constant, and the rapid heating and quenching treatment of the long wire can be performed under uniform conditions.

(3) It is possible to produce an Nb ₃ Al compound-based superconducting wire having a stable (homogeneous) critical current density characteristic in the longitudinal direction of the wire.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.

  Initially, the multi-wire 12 used for Examples 1-6 and Comparative Examples 1-3 was produced as follows. First, a single wire 8 as shown in FIG. 1 is manufactured using an Nb center member 4 having an outer diameter of 5 mm, a pure Nb sheet 2 having a thickness of 80 μm, and a pure Al sheet 3 having a thickness of 25 μm. Next, 85 single wires 8 were inserted into the Nb tube 9, and then inserted into the Cu—Ni tube 10, followed by hydrostatic extrusion, and wire drawing was performed to produce a multi-wire 12. The produced multi-wire 12 has a wire diameter of 1.35 mm and a length of 300 m (in Example 6, a length of 400 m).

Example 1
Using the rapid heating and quenching apparatus 30 (first embodiment) shown in FIG. 3, the produced multi-wire 12 was subjected to rapid heating and quenching treatment to generate a supersaturated solid solution.

(Example 2)
Using the rapid heating and quenching apparatus 40 (second embodiment) shown in FIG. 4, the produced multi-wire 12 was subjected to rapid heating and quenching treatment to generate a supersaturated solid solution. Here, as the raising jig 36, a stainless steel rod having an alumina coating on its surface was used.

(Example 3)
Using the rapid heating and quenching device 50 (third embodiment) shown in FIG. 5, the produced multi-wire 12 was subjected to rapid heating and quenching treatment to generate a supersaturated solid solution.

Example 4
Using the rapid heating and quenching apparatus 60 (fourth embodiment) shown in FIG. 6, the produced multi-wire 12 was subjected to rapid heating and quenching treatment to generate a supersaturated solid solution. Here, as the raising jig 36, a stainless steel rod having an alumina coating on its surface was used.

(Comparative Example 1)
Using the rapid heating and quenching apparatus 20 shown in FIG. 13, the produced multi-wire 12 was subjected to rapid heating and quenching treatment to generate a supersaturated solid solution.

Table 1 shows the rapid heating and quenching treatment conditions in Examples 1 to 4 and Comparative Example 1 (the main points of the device used, the energization current value during the treatment), the measurement results of the generated voltage at the start and end of the treatment, and the produced wire The critical current values in the magnetic field 21T and the temperature of 4.2K at the front and rear ends (at the start and end of processing) of FIG. Here, the process was conducted with a constant current, and the voltage between the energized capstan 22 and the liquid Ga27 was defined as the generated voltage. In addition, the sample for measuring the critical current characteristics is subjected to a reheating treatment at 800 ° C. for 10 hours for precipitating the Nb ₃ Al compound phase. In addition, since the wire composition in each example is the same, the comparison of critical current characteristics can be regarded as a comparison of critical current density characteristics.

  According to Table 1, in Examples 1 to 4 in which the rapid heating and quenching treatment was performed using a mechanism that keeps the liquid level constant, the change in the liquid level before and after the treatment was -0.01 to It can be seen that the liquid level is kept almost constant, being as small as −0.02 mm. In addition, since the liquid level is constant, the energization distance (joule heat generation section length) does not change, and accordingly, the generated voltage also varies as small as 0 to 0.1 V from the start to the end of the process. It can be seen that the rapid heating and quenching process is performed while the processing conditions are kept constant. Furthermore, a superconducting wire having a very uniform characteristic in the longitudinal direction of the wire, in which the change in critical current value is 2% or less at the front and rear ends of the wire, has been produced.

  On the other hand, in Comparative Example 1 in which the rapid heating and quenching process was performed without using a mechanism for keeping the liquid level constant, the liquid level decreased by 1.42 mm before and after the process, and the energization distance (the Joule heating section length) ) Increases with an increase of 0.9 V, indicating that the rapid heating and quenching process under stable (uniform) processing conditions has not been performed. In addition, since the processing conditions change in the longitudinal direction of the wire, the superconducting characteristics at the front and rear ends of the wire also change, and only about 90% of the critical current at the front end flows at the rear end where the conditions change. As a result, it can be seen that a superconducting wire inhomogeneous in the longitudinal direction of the wire is produced.

  From these results, in order to produce a superconducting wire having uniform critical current density characteristics by performing rapid heating and quenching treatment under uniform processing conditions in the longitudinal direction of the wire, the liquid level of the cooling metal material (Ga) It can be seen that measures to maintain a constant value are effective.

(Example 5)
In the rapid heating / cooling apparatus 30 shown in FIG. 3, a multi-piece manufactured by an apparatus (fifth embodiment) using a reel 24B provided with a small reel 24b shown in FIG. The wire 12 was subjected to rapid heating and quenching treatment to produce a supersaturated solid solution. The energizing current value at the time of processing was 223A.

(Comparative Example 2)
On the other hand, using the rapid heating and quenching apparatus 20 shown in FIG. 13 (including the reel 24A of FIG. 7A), the produced multi-wire 12 was subjected to rapid heating and quenching treatment to generate a supersaturated solid solution. The energizing current value at the time of processing was 228A.

  About the comparative example 2 and Example 5, the measurement of the generated voltage in the energization at the time of a rapid heating quenching process was performed. FIGS. 9 and 10 show part of the measurement results of the generated voltage in the wires of Comparative Example 2 and Example 5 (wire length 10 m), respectively.

  As is clear from FIGS. 9 and 10, in Comparative Example 2, the energized distance fluctuates when the liquid surface of the liquid Ga shakes (vibrates), and thus the generated voltage fluctuates. On the other hand, in Example 5, since the fluctuation of the liquid Ga liquid level was suppressed, the fluctuation of the generated voltage could be extremely reduced.

(Example 6)
In the rapid heating / quenching apparatus 30 shown in FIG. 3, the produced multi-wire 12 (400 m) is rapidly heated and cooled by the apparatus (sixth embodiment) in which the cooling container 26 moves up and down as shown in FIG. To produce a supersaturated solid solution. The energization current value at the time of processing was 217A.

(Comparative Example 3)
On the other hand, using the rapid heating and quenching apparatus 20 shown in FIG. 13, the produced multi-wire 12 was subjected to rapid heating and quenching treatment to generate a supersaturated solid solution. The current value during processing is
At 217A.

  The generated voltage was measured for each of Example 6 and Comparative Example 3, and the measurement results of the generated voltage at a length of about 153 m (Comparative Example 3) and about 400 m (Example 6) of the wire material subjected to the rapid heating and quenching treatment are shown in FIG. , Shown in FIG.

  As is apparent from FIGS. 11 and 12, in Comparative Example 3, the energized distance fluctuates due to a decrease in the liquid Ga, and thus the generated voltage fluctuated (which was on the rise, about 0 at about 150 m). .2V increase). On the other hand, in Example 6, since the liquid surface height of the liquid Ga was kept almost constant, the generated voltage could be made almost constant (the fluctuation at about 400 m is within about 0.1 V).

And shows the shape of the wire in each manufacturing step in a manufacturing method of Nb 3 _Al compound superconducting wire according to an embodiment of the present invention, (a) is a sectional view of a composite strand, (b) is The perspective view which shows a single wire, (c) is a perspective view which shows a composite wire, (d) is sectional drawing which shows a multi wire. It is a flow chart of a method for manufacturing a Nb 3 _Al compound superconducting wire according to an embodiment of the present invention. It is a schematic block diagram of the manufacturing apparatus (rapid heating rapid cooling apparatus) which concerns on the 1st Embodiment of this invention. It is a schematic block diagram of the manufacturing apparatus (rapid heating rapid cooling apparatus) which concerns on the 2nd Embodiment of this invention. It is a schematic block diagram of the manufacturing apparatus (rapid heating rapid cooling apparatus) which concerns on the 3rd Embodiment of this invention. It is a schematic block diagram of the manufacturing apparatus (rapid heat quenching apparatus) which concerns on the 4th Embodiment of this invention. It is the schematic which shows the structure of the reel accommodated in the container for cooling, (a) is based on the conventional rapid thermal quenching apparatus, (b) is the rapid change which concerns on the 5th Embodiment of this invention. This relates to a thermal quenching device. It is a partially expanded schematic diagram of the rapid heating and quenching apparatus according to the sixth embodiment of the present invention. It is a figure which shows the measurement result of the generated voltage in the comparative example 2. It is a figure which shows the measurement result of the generated voltage in Example 5. FIG. It is a figure which shows the measurement result of the generated voltage in the comparative example 3. It is a figure which shows the measurement result of the generated voltage in Example 6. FIG. It is a schematic block diagram of the conventional manufacturing apparatus (rapid heating rapid cooling apparatus) used for manufacture of the superconducting wire by the rapid heating rapid cooling transformation method.

Explanation of symbols

1: Laminated body 2: Nb sheet 3: Al sheet 4: Center material 5: Nb coating 6: Cu coating 7: Composite wire 8: Single wire 9: Nb tube 9 ': External matrix 10: Cu-Ni alloy tube 11 : Composite wire 12: Multi-wire 20, 20, 40, 50, 60: Rapid heating / cooling device 21: Feeding reel 22: Current supply capstan 23: DC power supply 24, 24A, 24B: Reel 24b: Small reel 25: Winding Reel 26: Cooling container 27, 33: Liquid Ga
34: Liquid level sensor 31: Housing 31A: First housing 31B: Second housing 32: Adjustment container 35: Ga injection port 36: Raising jig 37: Sensor head 38: Special metal

Claims (17)

A wire containing Nb or Nb alloy and Al or Al alloy is rapidly heat-treated by Joule heat generation of the wire, and then rapidly cooled through the wire through the wire to form a Nb-Al supersaturated solid solution. A method for producing a Nb ₃ Al compound-based superconducting wire using a rapid heating / quenching / transformation method, in which an Nb ₃ Al compound phase is precipitated by reheating,
An Nb ₃ Al compound-based superconducting wire characterized in that a treatment for making the liquid surface height of the cooling liquid metal material constant is performed as a treatment for making the Joule heating section length constant during manufacture Manufacturing method. The wire is formed by coating a matrix material of Nb or Nb alloy around a laminate made of Nb or Nb alloy and Al or Al alloy to form a single wire, and a plurality of the single wires are bundled around Nb. 2. The method for producing an Nb ₃ Al compound-based superconducting wire according to claim 1, wherein the wire is a multi-wire formed by coating a matrix material of an Nb alloy. The treatment for making the liquid level constant is performed by measuring the liquid level of the cooling liquid metal material and injecting the cooling liquid metal material according to the changed liquid level height. The method for producing an Nb ₃ Al compound-based superconducting wire according to claim 1. The treatment for making the liquid level height constant is to measure the liquid level height of the cooling liquid metal material, and to change the liquid material for cooling to the metal material according to the changed liquid level height. 2. The method for producing a Nb ₃ Al compound-based superconducting wire according to claim 1, wherein the method is carried out by sinking a substance having a surface that does not substantially cause a reaction. 5. The method of manufacturing an Nb ₃ Al compound-based superconducting wire according to claim 4, wherein the substance having a surface that does not substantially cause a chemical reaction with the cooling metal material is an alumina-coated substance. . The treatment for making the liquid level height constant is performed by measuring the liquid level height of the cooling liquid metal material and moving the cooling container up and down according to the changed liquid level height. the method according to claim 1 Nb 3 _Al compound superconducting wire, wherein. A wire containing Nb or Nb alloy and Al or Al alloy is rapidly heat-treated by Joule heat generation of the wire, and then rapidly cooled through the wire through the wire to form a Nb-Al supersaturated solid solution. A method for producing a Nb ₃ Al compound-based superconducting wire using a rapid heating / quenching / transformation method, in which an Nb ₃ Al compound phase is precipitated by reheating,
When the cooling treatment is performed, the wire is sent by a plurality of reels that are entirely embedded in the cooling liquid metal material. A method for producing an Nb ₃ Al compound-based superconducting wire. The method for producing a Nb ₃ Al compound-based superconducting wire according to any one of claims 1 to 7, wherein the cooling metal material is liquid gallium (Ga). It claims 1 to Nb 3 _Al compound superconducting wire which is characterized by being manufactured by the manufacturing method of the Nb 3 _Al compound superconducting wire according to any one of claims 8. Sending reel for feeding wire containing Nb or Nb alloy and Al or Al alloy, heating means for rapidly heating the wire, cooling container for storing a cooling liquid metal material for rapidly cooling the wire, inside the cooling container A Nb ₃ Al compound-based superconducting wire manufacturing apparatus provided with a reel for feeding the wire provided on a winding and a take-up reel for winding the wire,
Nb ₃ further comprising an injection port for injecting the cooling liquid metal material in accordance with the liquid level of the cooling liquid metal material in order to make the length of the Joule heating section during manufacture constant. Al compound superconducting wire manufacturing equipment. A first casing in which the cooling container is disposed; and a second casing in which an adjustment container communicating with the cooling container is disposed; and the injection port includes the adjustment container The apparatus for producing a Nb ₃ Al compound-based superconducting wire according to claim 10, wherein the cooling liquid metal material is poured into a container. Sending reel for feeding wire containing Nb or Nb alloy and Al or Al alloy, heating means for rapidly heating the wire, cooling container for storing a cooling liquid metal material for rapidly cooling the wire, inside the cooling container A Nb ₃ Al compound-based superconducting wire manufacturing apparatus provided with a reel for feeding the wire provided on a winding and a take-up reel for winding the wire,
Nb further comprising a substance having a surface that does not substantially cause a chemical reaction with the metal material submerged in the cooling liquid metal material according to a liquid level of the cooling liquid metal material. ₃ Al compound-based superconducting wire manufacturing equipment. A first casing in which the cooling container is disposed; and a second casing in which an adjustment container communicating with the cooling container is disposed; 13. The Nb ₃ Al compound-based superconducting wire according to claim 12, wherein the substance having a surface that does not cause a chemical reaction is submerged in the cooling liquid metal material in the adjustment container. apparatus. 13. The apparatus for producing an Nb ₃ Al compound-based superconducting wire according to claim 12, wherein the substance having a surface that does not substantially cause a chemical reaction with the cooling metal material is an alumina-coated substance. 14. The apparatus for producing a Nb ₃ Al compound-based superconducting wire according to claim 11 or 13, wherein the first casing and the second casing are in an equal vacuum state. Sending reel for feeding wire containing Nb or Nb alloy and Al or Al alloy, heating means for rapidly heating the wire, cooling container for storing a cooling liquid metal material for rapidly cooling the wire, inside the cooling container A Nb ₃ Al compound-based superconducting wire manufacturing apparatus provided with a reel for feeding the wire provided on a winding and a take-up reel for winding the wire,
Nb ₃ Al, further comprising a control mechanism for moving the cooling container up and down according to the liquid level of the cooling liquid metal material in order to make the Joule heat generation section length during manufacture constant. Compound superconducting wire manufacturing equipment. The Nb ₃ Al compound-based superconducting wire manufacturing apparatus according to any one of claims 10 to 16, wherein the cooling metal material is liquid gallium (Ga).

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