JPH02227248A - Connecting method for oxide conductive material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for connecting oxide superconductors.

[Prior Art and Problems to be Solved by the Invention] Various oxide conductors have been developed in recent years, and it is expected that oxide superconductors will be applied in various fields in the near future. When considering the application of oxide superconductors, it is essential to develop a technology to connect superconductors, but such technology has not yet been developed.

An object of the present invention is to propose a method for connecting oxide superconductors.

[Means for Solving the Problem] In the invention described in claim 1, a pair of oxide superconductors 1.2 to be connected are brought into contact with each other under pressure as shown in FIG. 1 or FIG. , both oxide superconductors are joined by heating the contact portion 3 of the pair of oxide superconductors.

The method of contacting the oxide superconductors 1 and 2 is arbitrary. For example, when the oxide superconductors 1 and 2 are plate-shaped, as shown in FIG. As shown in FIG. 2, the oxide superconductors 1.degree. 2 may be butted against each other in the thickness direction to apply a pressing force f.

The contact portion may be heated by passing an electric current through the contact portion, or may be heated by irradiating the contact portion with a laser.

In the invention set forth in claim 4, as shown in FIG. 3 or 4, the pair of oxide superconductors 1.2 to be connected are connected via an intermediate body 5 containing an oxide superconductor. Both oxide superconductors are pressurized in a direction to bring them closer to each other, and the abutting portions 6 of the paired oxide superconductors are heated to connect both superconductors.

FIG. 3 shows a case in which plate-shaped oxide superconductors 1 and 2 are butted together in the longitudinal direction with an intermediate body 5 interposed therebetween, and FIG. 5 is shown in which they are butted together in the thickness direction.

As the intermediate 5, a paste of an oxide superconductor or a paste containing an oxide superconductor and carbon can be used.

In this case as well, the abutting portion may be heated by passing an electric current through the abutting portion, or may be heated by irradiating the abutting portion with a laser.

When the connection portion formed by each of the above methods exhibits semiconductor-like behavior, the connection portion does not exhibit superconductivity. In this case, by further heat-treating the connecting portion, the connecting portion can be made to have superconductivity.

[Operation] Oxide superconductors could be connected to each other by the method described above. If oxide superconductors are simply connected by butting each other directly or through an intermediate and heating, the connection will exhibit semiconductor-like behavior (the resistance value increases as the temperature decreases), and the connection will may not exhibit superconductivity. In this case, when the connecting portion is heat-treated, the connecting portion exhibits metallic behavior (a characteristic in which the resistance value decreases as the temperature decreases), and the connecting portion can be made to have superconductivity.

[Example 1] Temporarily fired YBa2 Cu307-J (hereinafter referred to as YB
It's called CO. ) powder at 1.0 [ton/cm'
] The length was 15 m as shown in Figure 5.
A cylindrical oxide superconductor pellet (critical temperature 93 [K]) with a diameter of 1 mm and a diameter of 1 mm was prepared.

Oxide superconductor pellets prepared in this manner 11.
12 were abutted against each other as shown in FIG. 6, and one end surface of each in the axial direction was brought into contact, and the other end surface of one of the pellets 11 was brought into contact with an electrode 14 supported on a pedestal 13. An electrode 15 was brought into contact with the other end surface of the other pellet 12, a weight 16 of 1.0 kg was placed on the electrode 15, and the contact portions 17 of the pellets 11 and 12 were pressurized. Further, the electrode 14 is connected to one output terminal of the DC power supply 18, and the electrode 15 is connected to the other output terminal of the DC power supply 18 through the ammeter 19 and the switch 20, and the connection point between the switch 20 and the ammeter 19 is connected. A voltmeter 21 was connected between the electrode 14 and the electrode 14 .

Then, the power supply voltage is 115 [V] and 225 [A]
When the N current was applied for 1.5 minutes and the temperature near the contact area of the pellet 11.12 was measured using the radiation thermometer 22, the temperature at the contact area at the end of the current application was 920°C.

Although the pellets 11 and 12 could be connected by the above-described energization, it became clear that the connected portion exhibited semiconductor-like behavior and did not exhibit superconductivity.

Therefore, when the sample connected as described above was subjected to heat treatment at 950° C. for 10 hours in an oxygen atmosphere, the connected portion began to exhibit metallic behavior. In order to investigate the characteristics of the connection portion after heat treatment, the temperature characteristics of the resistance value of the connection portion were measured by the four-terminal method shown in FIG. That is, the connected pellets 11 and 12 are connected to a constant current source 24 via an ammeter 23, and a voltmeter 25 is connected between the pellets 11 and 12.
The resistance value at each temperature was calculated from the measured values of the ammeter 23 and the voltmeter 25. The results are shown in FIG. 10, and it was possible to obtain an initial critical temperature of YBCO of 93 [K].

[Example 2] YBCO powder was fired at a pressure of 1.0 ton/curl to form a powder of 7 mm x 7 mm x 1 as shown in Fig. 9.
5 mm rectangular parallelepiped oxide superconductor pellets (critical temperature 93 [K]) 31 and 32 were created. As shown in FIG.
was pushed toward the pellet 31 side with a weak spring force to pressurize the abutting portion of both pellets. Furthermore, fixing tables 35, 36 are arranged on both sides of the pellet 31, 32, and tungsten electrodes 37, 38 are supported on these fixing tables, respectively.
The abutting portion (intermediate body 33) having an angle of 32° was contacted from the side. Then, an ammeter 42 is connected to the electrode 37 via a switch 41.
A DC power source 43 was connected between the other end of the ammeter 42 and the electrode 38. A voltmeter 44 was also connected to measure the power supply voltage.

As the intermediate 33, a paste containing oxide superconductor powder, preferably a paste containing a mixture of oxide superconductor powder and carbon powder is used.

In the example, intermediate body 33 was formed by adding 10% carbon powder to YBCO powder and making it into a paste with screen oil, and uniformly applying this to the bonding surface of pellets 31 and 32 to a thickness of 1 μm.

After the above preparations are completed, close the switch 41 and
When a current of 0 A (voltage 90 [V]) was applied for 2.0 minutes, the temperature of the abutted portion reached 1,100° C., and pellets 31 and 32 were joined. When this sample was heat-treated at 950°C for 10 hours in an oxygen atmosphere and the temperature characteristics of the resistance were measured using the four-terminal method, the results shown in Figure 11 were obtained, and the initial critical temperature of YBCO was 93 [K]. ]
I was able to get

[Effects of the Invention] As described above, the method of the present invention has the advantage that oxide superconductors can be connected to each other and the range of application of oxide superconductors can be expanded.

[Brief explanation of the drawing]

1 and 2 show the method of the invention as set forth in claim 1, and in FIG. 1, the method of the invention is carried out by abutting a pair of oxide superconductors in the longitudinal direction. FIG. 2 is an explanatory diagram showing a state in which the method of the present invention is carried out by abutting oxide superconductors in the thickness direction. 3 and 4 show the method of the invention according to claim 4, and in FIG. 3, the method of the invention is carried out by abutting a pair of oxide superconductors in the longitudinal direction. FIG. 4 is an explanatory diagram showing a state in which the method of the present invention is carried out by abutting oxide superconductors in the thickness direction. Fig. 5 is a perspective view showing the pellet used in the first embodiment of the present invention, Fig. 6 is a connection diagram schematically showing the configuration of the device used in the same embodiment, and Fig. 7 is a 4-terminal diagram. An explanatory diagram explaining the law,
FIG. 8 is a connection diagram schematically showing the configuration of the device used in the second embodiment of the present invention, FIG. 9 is a perspective view showing the pellet used in the second embodiment of the present invention, and FIG. FIG. 10 and FIG. 11 are diagrams showing the temperature characteristics of the resistance of samples obtained in the first and second examples of the present invention, respectively. 1.2...Oxide superconductor, 11. 12. 31゜32...Oxide superconductor pellet, 18.43...
DC power supply, 33... intermediate body, 38.39... electrode. π ←1self゛101 ←Wv−self

Claims (9)

[Claims] (1) A pair of oxide superconductors to be connected are brought into contact with each other under pressure, and both oxide superconductors are joined by heating the contact portion of the pair of oxide superconductors. How to connect oxide superconductors. (2) The method for connecting oxide superconductors according to claim 1, wherein the heating of the contact portion is performed by passing current through the contact portion. (3) The method for connecting oxide superconductors according to claim 1, wherein the heating of the contact portion is performed by irradiating the contact portion with a laser. (4) Pairs of oxide superconductors to be connected are butted together via an intermediate containing the oxide superconductors, and pressure is applied in a direction to bring both oxide superconductors closer to each other. A method for connecting oxide superconductors that connects both superconductors by heating the butt portions of the superconductors. (5) The method for connecting an oxide superconductor according to claim 4, wherein the intermediate is a paste of an oxide superconductor. (6) The method for connecting oxide superconductors according to claim 4, wherein the intermediate is a paste containing an oxide superconductor and carbon. (7) The method for connecting oxide superconductors according to any one of claims 4 to 6, wherein the heating is performed by applying electricity through the butt portion. (8) The method for connecting oxide superconductors according to any one of claims 4 to 6, wherein the heating is performed by irradiating the abutted portion with a laser. (9) The oxide superconductor according to any one of claims 1 to 8, wherein after the pair of oxide superconductors are connected, a heat treatment is performed on the connecting portion of both superconductors. Connection method.