JP2841933B2 - Manufacturing method of oxide superconducting wire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an oxide superconducting wire.

[0002]

2. Description of the Related Art In recent years, ceramic superconducting materials, that is, oxide superconducting materials, have attracted attention as superconducting materials exhibiting higher critical temperatures. Among them, Bi system is 110K
The Tl system shows a high critical temperature of about 120K, and its practical use is expected.

It is known that such a superconducting material has a plurality of superconducting phases having different crystal structures and critical temperatures. It is also known that when such a superconducting material is manufactured by heat-treating a raw material powder, some superconducting phases are likely to be mixed, and some non-superconducting phases appear. Further, using such a superconducting material, as a method of obtaining a superconducting wire, coating the raw material powder with a metal sheath, or coating on the substrate, or or the raw material powder into a fiber,
There is known a method for producing a superconducting wire by heat-treating the raw material powder to make it superconductive.

[0004]

However, when applying a superconducting wire to a cable or a magnet,
In addition to a high critical temperature, it is necessary to have a high critical current density and a large current. The oxide superconducting wires obtained so far are still insufficient in that a large current can be stably passed at a high critical current density.

An object of the present invention is to provide a method for producing an oxide superconducting wire having a high critical current density and capable of stably flowing a large current.

[0006]

According to the method for manufacturing an oxide superconducting wire of the present invention, a step of adjusting an oxide superconductor covered with a metal sheath, a step of stacking a plurality of oxide superconductors, and placing the superconductors in a range of 200 to 700 Forming an oxide superconducting wire in which a plurality of oxide superconductors are laminated via a metal sheath while simultaneously performing a heat treatment at a temperature of 50 ° C. and a pressure load of 50 to 1000 kg / cm ² .

[0007] When the metal sheath is a silver sheath, the temperature of the heat treatment is preferably 100 ° C to 800 ° C, more preferably 200 ° C to 700 ° C. Further, the load of the pressing is preferably 30 to 2000 kg / cm ² , more preferably 50 to 1000 kg / cm ² .

[0008]

The oxide superconducting wire produced by the method of the present invention has the following properties:
Heat treatment at 00-700 ° C and pressure loading 50-1
The oxide superconductor is formed by laminating through a multi-layer metal sheath by pressure processing at 000 kg / cm ² . For this reason, each oxide superconductor layer has high orientation,
It has a high critical current density. In addition, since a plurality of oxide superconductor layers are stacked, a large current can flow stably, and since the layers are even laminated via a metal sheath, a large current can flow stably.

[0009]

According to the manufacturing method of the present invention, it is possible to obtain an oxide superconducting wire capable of stably flowing a large current. Therefore, it is expected that the oxide superconducting wire produced by the method of the present invention can be put to practical use in cables, magnets and the like.

[0010]

【Example】

Example 1 A Tl-Pb-Ba-Ca-Cu-O-based oxide superconducting material powder was filled in a silver sheath and then processed into a tape shape. This tape-shaped wire was heat-treated at 800 ° C. for 4 hours. The wires were stacked in 10 layers, and were subjected to pressure processing while applying a load of 100 kg / cm ² while being heated to 400 ° C. and heat-treated.

FIG. 1 is a sectional perspective view showing one embodiment of the oxide superconducting wire according to the present invention thus obtained. Referring to FIG. 1, an oxide superconducting wire 1 is formed from an oxide superconductor layer 2 laminated via a metal sheath 3. The arrow A is the longitudinal direction of the wire,
Current direction. The liquid nitrogen temperature (7
The critical current value at 7.3K) was measured, and the results are shown in Table 1.

For comparison, a critical current value was similarly measured for an oxide superconducting wire 11 in which a metal sheath 13 covered one oxide superconductor 12 as shown in FIG. No. of this comparative example. The cross-sectional area of the superconductor portion of the wire of No. 0 and the thickness of the entire wire are as shown in Table 1. This is almost the same as the first embodiment.

[0013]

[Table 1]

Example 2 In the same manner as in Example 1 above, the oxide superconducting material powder was filled into a silver sheath, processed into a tape shape, and the heat-treated wire was heat-treated at the heating temperature and load shown in Table 2 and pressed. Under the processing conditions, an oxide superconducting wire as shown in FIG. 1 was produced in the same manner as in Example 1.

The critical current value of the thus obtained wire at liquid nitrogen temperature (77.3K) was measured and is shown in Table 2.

[0016]

[Table 2]

As is clear from Table 2, the pressure processing
Load is 30-2000kg / cm ^TwoIs preferred, and
Preferably 50 to 1000 kg / cm^TwoIt is. Example 3 A tape-shaped wire was produced in the same manner as in Example 1 above.
Heat treatment, and using this wire, the heating temperature and
Fig. 1 shows the conditions of heat treatment and load
Such an oxide superconducting wire was produced.

The critical current value of the thus obtained wire at liquid nitrogen temperature (77.3K) was measured. The results are shown in Table 3.

[0019]

[Table 3]

As is clear from Table 3, the temperature of the heat treatment at the time of press working is preferably from 100 to 800 ° C., and more preferably from 200 to 700 ° C. Example 4 A Bi-Pb-Sr-Ca-Cu-O-based oxide superconducting material powder was filled in a silver sheath, processed into a tape shape, and this tape-shaped wire was heat-treated at 800 ° C for 10 hours. Using this wire, while heat-treating at a heating temperature of 400 ° C,
Pressure processing was performed with a load of 100 kg / cm ² to produce an oxide superconducting wire as shown in FIG.

The critical current value of this wire at a liquid nitrogen temperature (77.3K) was measured. The results are shown in Table 4. For comparison, an oxide superconducting wire composed of one superconductor layer as shown in FIG. 2 was produced, and the critical current value was measured in the same manner. The results are shown in Table 4. It should be noted that the comparative example No. Table 4 shows the cross-sectional area of the oxide superconductor of No. 0 and the thickness of the wire rod. It is almost the same as 1.

[0022]

[Table 4]

As is clear from Table 4, according to the present invention, No. 2 having a plurality of stacked oxide superconductor layers. No. 1 wire is No. 0 indicates a higher critical current than the comparative example. Example 5 A tape-shaped wire was produced in the same manner as in Example 4 described above, and after this was heat-treated, the wire was subjected to pressure processing while being heat-treated under the conditions of a heating temperature and a load shown in Table 5 below. An oxide superconducting wire as shown in FIG. 1 was produced.

The critical current value of the thus obtained wire at liquid nitrogen temperature (77.3K) was measured. The results are shown in Table 5.

[0025]

[Table 5]

As is apparent from Table 5, the load condition during the pressing is preferably 30 to 2000 kg / cm ² , more preferably 50 to 1000 kg / cm ² . Example 6 A tape-shaped wire was prepared and heat-treated in the same manner as in Example 4, and this wire was heat-treated and pressed under the conditions shown in Table 6 to obtain an oxide superconductor as shown in FIG. A wire was produced.

The critical current value of the thus obtained wire at liquid nitrogen temperature (77.3K) was measured. The results are shown in Table 6.

[0028]

[Table 6]

As is clear from the results in Table 6, the heating temperature of the heat treatment is preferably from 100 to 800 ° C, more preferably from 200 to 700 ° C. Example 7 A powder of Tl-Bi-Sr-Ca-Cu-O-based oxide superconducting material was filled in a silver sheath, and then processed into a tape shape.
This tape-shaped wire was heat-treated at 800 ° C. for 8 hours. Using this wire, heating temperature 400 ° C, load 100kg / cm
Heat treatment and pressure processing were performed simultaneously under the conditions of ² , and FIG.
An oxide superconducting wire as shown in FIG.

For this wire, the temperature of liquid nitrogen (77.
3K) was measured, and the results are shown in Table 7. As a comparison, a wire was prepared in which the periphery of one oxide superconductor was covered with a metal sheath as shown in FIG. 2, and the critical current value was measured for this wire, and the results are shown in Table 7. It should be noted that the comparative example No. As shown in Table 7, the cross-sectional area of the oxide superconductor of the wire of No. 0 and the thickness of the wire were as follows. It is almost the same as 1.

[0031]

[Table 7]

As is clear from Table 7, a wire in which a plurality of oxide superconductor layers are laminated via a metal sheath according to the present invention exhibits a high critical current. Example 8 A tape-shaped wire was produced and heat-treated in the same manner as in Example 7, and an oxide superconducting wire as shown in FIG. 1 was produced under the heat treatment and pressure processing conditions shown in Table 8.

The critical current value of the thus obtained wire at liquid nitrogen temperature (77.3K) was measured. The results are shown in Table 8.

[0034]

[Table 8]

As is clear from Table 8, the load for the pressing is preferably 30 to 2000 kg / cm ² , more preferably 50 to 1000 kg / cm ² . Example 9 A tape-shaped wire was produced in the same manner as in Example 7, and after heat-treating it, it was heat-treated and pressed under the conditions shown in Table 9 to produce an oxide superconducting wire as shown in FIG.

The critical current value of the thus obtained wire at liquid nitrogen temperature (77.3K) was measured. The results are shown in Table 9.

[0037]

[Table 9]

As apparent from Table 9, the heating temperature for the heat treatment is preferably from 100 to 800 ° C., and more preferably from 200 to 700 ° C.

[Brief description of the drawings]

FIG. 1 is a cross-sectional perspective view showing one embodiment of an oxide superconducting wire manufactured by the method of the present invention.

FIG. 2 is a sectional perspective view showing an oxide superconducting wire of a comparative example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Oxide superconducting wire 2 Oxide superconductor layer 3 Metal sheath layer

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-134822 (JP, A) JP-A-2-247906 (JP, A) JP-A-64-12415 (JP, A) JP-A-2-124 227918 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01B 12/10 H01B 13/00 565 D

Claims (2)

(57) [Claims] 1. A method for producing an oxide superconducting wire in which an oxide superconductor is covered with a metal sheath, comprising: adjusting an oxide superconductor covered with a metal sheath; Stack this, 200-70
Heat treatment at 0 ° C and at the same time pressurized 50-1000kg
/ Cm ² to form an oxide superconducting wire in which a plurality of oxide superconductors are laminated via a metal sheath, to form an oxide superconducting wire. 2. A method for producing an oxide superconducting wire in which an oxide superconductor is covered with a metal sheath, comprising: filling a metal pipe with an oxide superconducting material powder; Heat treating at a temperature of 200 to 700 ° C. and simultaneously applying a pressure of 50 to 1000 kg / cm ^2.
Forming an oxide superconducting wire in which a plurality of oxide superconductors are laminated via a metal sheath.