JPH084043B2 - How to join superconductors - Google Patents

Description

TECHNICAL FIELD The present invention relates to a superconductor joining method for joining a superconducting layer made of an oxide superconducting material on a substrate.

"Prior art" Conventionally, as a method for joining superconductors such as a superconducting magnet coil, a method of winding a thin wire made of an alloy superconducting material such as an Nb-Ti alloy on a base body made of a normal conductor and joining the wires. Alternatively, there is known a method in which a compound superconducting material such as Nb ₃ Sn is soldered on a substrate and then the compound superconducting material is mechanically cut into a coil shape.

By the way, recently, the critical temperature of La-Ba-Cu-
O-based, Y-Ba-Cu-O-based, etc., so-called AB-Cu-O-based (A: Sc, Y, La ... Periodic Table Group IIIA metal elements, B: Ba, Sr, B
E-based alkaline earth metal oxide superconductors are being found one after another. Since these oxide-based superconductors have excellent characteristics such as a higher critical temperature than the above-mentioned alloy-based or compound-based superconductors and being considered as a superconducting material at a liquid nitrogen temperature or higher, the superconducting magnet coil It is expected to be applied and put to practical use.

"Problems to be Solved by the Invention" However, effective means for applying these oxide-based superconductors to a superconducting magnet coil has not yet been developed.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a joining method capable of providing a superconducting pattern made of an oxide-based superconductor on a base material in a strongly joined state.

[Means for Solving Problems] In the first aspect of the present invention, a coating layer made of an oxide superconducting material is formed on a substrate made of a normal conductor, and then the substrate and the coating layer are added. A method of solving the problem was to perform pressure firing and then remove a part of the coating layer to form a superconducting pattern.

In the second invention, a coating layer made of an oxide superconducting material is formed on a substrate made of a normal conductor and having an oxidized surface, and then the substrate and the coating layer are subjected to pressure firing, and then The removal of a part of the coating layer to form a superconducting pattern was used as a solution to the problem.

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

1 and 2 are diagrams for explaining an example in which the first invention of the present invention is applied to a method for manufacturing a superconducting magnet coil. The example described here is for producing a disc-shaped superconducting magnet coil, and a plurality of superconducting magnet coils are laminated and used as a magnet coil.

In the example shown in FIGS. 1 and 2, first, as shown in FIG. 1, a disk-shaped substrate 3 made of a normal conductor is coated with a powder of an oxide-based superconducting material to cover it to form a coating layer 4. Form.
Here, as the normal conductor, a copper plate whose surface is oxidized is used, but other non-oxidized copper plate, aluminum plate, surface-oxidized aluminum plate, or tin sulfide plate may be used. The reason for oxidizing the surface of the copper plate is
When the surface is made of an oxide, when the oxide-based superconducting material applied to the surface is made into a superconductor as described later, the oxidized surface and the oxide-based coating layer 4 to be the superconductor are formed. This is to increase the strength of the joint. As the oxide-based superconducting material, a material in which an alkaline earth metal carbonate powder, an oxide powder of a Group IIIA metal element of the periodic table and a copper oxide powder are mixed in an appropriate ratio is used.

In this case, as the alkaline earth metal carbonate powder, barium (Ba), strontium (Sr), calcium (Ca), beryllium (Be) and other carbonates, such as barium carbonate, strontium carbonate, calcium carbonate, Powders such as beryllium carbonate are used. The reason why the carbonate is used here is that the oxide of an alkaline earth metal has water absorbency and is inconvenient. In addition, Periodic Table IIIA
As the oxide powder of the group metal element, scandium (S
c), yttrium (Y), lanthanum (La), Ce, Pr, N
Oxides of Group IIIA metal elements including lanthanides such as d, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and the like, such as scandium oxide, yttrium oxide, and lanthanum oxide. Powder is used. Further, as the copper oxide powder, powders of copper oxide such as CuO, Cu ₂ O and Cu ₃ O ₂ are used.

The mixing ratio of these powders varies depending on the oxide-based superconductor to be obtained. For example, in the Y-Ba-Cu-O-based oxide superconductor, the element weight ratio is Y: 0.6, Ba: 0.4, Cu: 1. , O: 3.

Next, pressure is applied to the substrate 3 and the coating layer 4 and firing is performed under this pressure. Then, the powdery oxide-based superconducting material forming the coating layer 4 becomes a disc-shaped superconductor, and the coating layer 4 is integrally joined to the substrate 3. Here, as the pressure at the time of pressurization, a pressure of about 1 to 10 kg / mm ² is applied. In addition, the firing conditions include the coating layer 4
The temperature is set to an appropriate temperature depending on the mixing ratio of the above-mentioned powder of the oxide-based superconductor material that constitutes the heating temperature of 800 to 110.
The temperature is 0 ° C. and the heating time is about 1 to 100 hours. Further, the coating layer 4 which has been fired into a superconductor is strongly bonded to the substrate 3 and a bonding strength of about 6 to 8 kg / mm ² is obtained.

After that, a part of the coating layer 4 made of a disc-shaped oxide-based superconductor is removed to form a spiral superconducting pattern 5 as shown in FIG. In this case, as a means for partially removing the coating layer 4, a known mechanical means such as cutting, a known chemical means such as etching, or the like is used.

In such a method for manufacturing a superconductor magnet coil, since the oxide-based superconducting material forming the coating layer 4 becomes a superconductor by pressure firing and is simultaneously joined to the substrate 3, the superconductor and the substrate 3 are A strong joint strength can be obtained. Further, in the superconducting magnet coil obtained by this manufacturing method, the linear expansion coefficient α of the normal conductor (copper in this example) that constitutes the substrate 3 and the oxide superconductor that constitutes the superconducting pattern are both Both are almost equal to 10 ^-5 units,
Therefore, inconvenience such as distortion due to temperature change is prevented.

FIG. 3 and FIG. 4 are diagrams for explaining another example in which the first invention of the present invention is applied to a method for manufacturing a superconductor magnet coil, and the example described here is one magnet coil. This is an example of a case where a circular tubular superconducting magnet coil that can be used is manufactured.

In this example, first, as shown in FIG. 3, an oxide superconducting material is adhered and coated on the outer peripheral surface of a circular base tube (base) 6 made of a normal conductor to form a coating layer 7. Here, a copper pipe whose surface is oxidized is used as the normal conductor.
In this case as well, the reason why the surface of the copper pipe was oxidized is that the oxide superconducting material applied on this surface is pressure-fired as described later by making the surface an oxide as in the previous example. This is to increase the strength of the bond between the oxidized surface and the oxide-based coating layer 7 that becomes the superconductor when the superconductor is made into a superconductor. Further, as the oxide-based superconducting material, the alkaline earth metal carbonate powder shown in the previous example and the periodic table II
A mixture of an oxide powder of a Group IA metal element and a copper oxide powder, to which water, a binder and the like are appropriately added, and which is prepared into a paste, is used.

Next, pressure is applied to the coating layer 7 and the base tube 6 and the coating layer 7 are fired under this pressure. Then, the oxide-based superconducting material forming the coating layer 7 becomes a cylindrical superconductor and is integrally joined to the base tube 6. In this case, the applied pressure, the firing temperature, and the firing time are almost the same as in the previous example.

After that, a part of the coating layer 7 made of an oxide-based superconductor formed in a tubular shape is removed to form a coil-shaped superconducting pattern 8 as shown in FIG. In this case, as a means for partially removing the coating layer 7, a known mechanical means such as cutting, a known chemical means such as etching, or the like is used.

In this example as well, the same operation and effect as in the case of the previous example shown in FIGS. 1 and 2 can be obtained, and one independent circular tubular shape is formed without stacking a plurality of sheets to form a magnet coil. The superconducting magnet coil can be obtained.

"Effects of the Invention" As described above, in the method for joining a superconductor according to the first aspect of the present invention, a coating layer made of an oxide superconducting material is formed on a substrate made of a normal conductor, and then these substrates are made. And the coating layer is subjected to pressure firing, after which a part of the coating layer is removed to form a superconducting pattern, so that the oxide-based superconducting material forming the coating layer becomes a superconductor by pressure firing. Since it is bonded to the substrate at the same time, a strong bonding strength between the superconducting pattern and the substrate can be obtained, and further, the superconducting pattern can be easily formed on the substrate.

In the method for joining superconductors according to the second aspect of the present invention, a coating layer made of an oxide-based superconducting material is formed on a substrate whose surface is an oxide, and then the substrate and the coating layer are subjected to pressure firing, and thereafter, Since a super-electric pattern is formed by removing a part of the coating layer, the oxide-based superconducting material forming the coating layer becomes a superconductor by pressure firing, and at the same time is firmly bonded to the substrate whose surface is oxide. To be joined to
A strong bonding strength between the superconducting pattern and the base can be obtained, and further, the superconducting pattern can be easily formed on the base.

[Brief description of drawings]

1 and 2 are views for explaining an example of the first invention of the method for joining superconductors according to the present invention, and FIG. 1 is a perspective view showing a state in which a coating layer is formed on a substrate. 2 is a perspective view showing a state in which a superconducting circuit pattern is formed, FIG.
FIGS. 4 and 5 are views for explaining another example of the first invention, FIG. 3 is a side sectional view showing a state in which a coating layer is formed on a base tube, and FIG. 4 is a superconductivity. It is a principal part sectional view which shows the state which formed the circuit pattern. 3 ... Substrate, 4, 7 ... Coating layer, 5, 8 ... Superconducting pattern, 6 ... Base tube (base).

Front page continuation (72) Inventor Shotaro Yoshida 1-5-1, Kiba, Koto-ku, Tokyo Fujikura Electric Line Co., Ltd. (72) Inventor Shoichi Hasegawa 1-1-5, Kiba, Koto-ku, Tokyo Fujikura Electric Line (72) Inventor Hiroshi Yamanouchi 1-5-1, Kiba, Koto-ku, Tokyo Fujikura Electric Line Co., Ltd. (72) Inventor Shigeyoshi Yokoyama 1-1-5, Kiba, Koto-ku, Tokyo Fujikura Electric Line Co., Ltd. In-house (56) Reference JP 63-241818 (JP, A) JP 63-245906 (JP, A)

Claims (2)

[Claims] 1. A coating layer made of an oxide-based superconducting material is formed on a base body made of a normal conductor, and then the base body and the coating layer are pressure-fired, after which a part of the coating layer is removed. A method for joining superconductors, which comprises forming a superconducting pattern. 2. A coating layer made of an oxide-based superconducting material is formed on a substrate which is made of a normal conductor and whose surface is oxidized, and then these substrates and the coating layer are subjected to pressure firing, and then the coating layer is formed. A method for joining superconductors, characterized in that a superconducting pattern is formed by removing a part thereof.