JP3033593B2 - Aluminum stabilized superconducting wire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an A-stabilized superconducting wire which is excellent in thermal electric conductivity and strength and is suitable for a conductor for magnets and the like.

[Conventional technology and its problems]

Conventionally, a single-core or multi-core superconducting wire in which a desired number of superconducting core materials such as Nb-Ti alloy wires are embedded in a Cu or Cu alloy matrix and compounded has been used as a conductor for magnets. Residual resistance ratio (30
High-purity A, whose electrical resistance ratio at 0K and 10K is much higher than Cu, is used as a stabilizing material to improve the thermal and electrical conductivity at cryogenic temperatures to improve the stabilizer, or to reduce the superconducting wire's weight ratio. Attempts have been made to reduce the cross section.

However, the high-purity A has a low strength, so that the superconductor may be deformed by the electromagnetic force during use.

[Means for solving the problem]

The present invention has been made as a result of intensive research in view of such a situation, and the purpose of the present invention is to provide a material A covering the outer periphery of a superconducting wire with a high-purity electrical resistance at cryogenic temperatures.
A alloy using A alloy which is lower than Cu and has sufficient strength to withstand the electromagnetic force generated in magnets etc.
It is to provide a stabilized superconducting wire.

That is, the present invention is an aluminum-stabilized superconducting wire obtained by coating an outer periphery of a single-core or multi-core superconducting wire in which a superconducting core material is embedded in a copper or copper alloy matrix with an aluminum material as a stabilizing material, The aluminum stabilizing material of the stabilized superconducting wire has a 0.2% proof stress at extremely low temperatures of 3 kg / mm ² or more and a residual resistance ratio (electric resistance ratio at 300K and 10K) of 700 or more.
A- containing 30 to 500 ppm of Zn, with the balance being A
It is a Zn alloy or an A-Si alloy containing 20 to 40 ppm of Si and the balance being A.

In the present invention, the production of the single-core and multi-core superconducting wires coated with the material A is performed as follows.

That is, a single-core superconducting wire is, for example, one core material of Nb-Ti is charged into a hollow body made of Cu, and this is integrated by composite extrusion,
Next, it is manufactured by subjecting it to elongation such as rolling and drawing.

The multi-core superconducting wire is manufactured by filling a plurality of the single-core superconducting wires into a hollow body made of Cu and subjecting them to the same composite extrusion and elongation as described above. By repeating the steps of filling and elongation, a multi-core superconducting wire in which a larger number of superconducting core materials are combined is manufactured.

Thus, the A-stabilized superconducting wire is manufactured by compounding the material A on the outer periphery of the single-core or multi-core superconducting wire manufactured as described above by complex integration processing, and further elongating this.

In the above, the extrusion method is applied to the composite integrated processing, and the rolling or drawing processing is applied to the elongation processing. In the drawing processing, the forced lubrication drawing method in which the processing in the cross-sectional direction is uniformly performed is particularly used. Are suitable.

In the present invention, a single-core or multi-core superconducting wire is coated with A
The reason for limiting the 0.2% proof stress of the stabilizing material to 3 kg / mm ² or more and the residual resistance ratio (RRR) to 700 or more is that the strength of the aluminum stabilized superconducting wire withstands the electromagnetic force when a magnet is used. This is because the strength is not obtained and the thermal and electrical properties at cryogenic temperatures are higher than those of the conventional material.

Thus, alloys satisfying the above-mentioned limits include A-30
-50 ppm Zn alloy or A-20-40 ppm Si alloy is used.

[Action]

Since the A-stabilized superconducting wire of the present invention uses an A-alloy having a 0.2% proof stress of 3 kg / mm ² or more at an extremely low temperature as an A-stabilizing material, the conventional high-purity Cu is used as a magnet conductor in terms of strength.
RRR indicating the thermal and electrical stability of the superconducting wire is 700 or more, significantly higher than 120 of high-purity Cu, and the electric resistance at cryogenic temperature is 1/3 of that of high-purity Cu. As a result, the electrical stability during use is improved. In addition, the cross section of the stabilizing material can be reduced by an amount corresponding to the reduced electric resistance, and as a result, the magnet can be reduced in size and weight when used as a magnet.

〔Example〕

 Hereinafter, the present invention will be described in detail with reference to Examples.

Example 1 An Nb-Ti alloy consisting of 50% of Ti and the balance of Nb and oxygen-free copper were integrated by extrusion, and then extra-fine multi-core Nb-Ti superconductor in which 1200-core NbTi filaments were embedded in a copper matrix by elongation. Make a wire and then
After processing to an alloy of 99.9993% purity, A alloy containing a trace amount of Zn is extruded by extrusion and coated with 6mmφ.
Then, this material was drawn by a forced lubrication drawing method to produce a 2.3 mmφ A-stabilized superconducting wire coated with a dilute A-Zn alloy. In the above, the Zn content in the alloy A was variously changed in the range of 30 to 50 ppm.

Example 2 In Example 1, an A-Si alloy was used for the A alloy,
An A-stabilized superconducting wire was manufactured in the same manner as in Example 1 except that its content was varied in the range of 20 to 40 ppm.

Comparative Example 1 In Example 1, the content of Zn in the A-Zn alloy was 30 pp.
An A-stabilized superconducting wire was manufactured in the same manner as in Example 1, except that the amount was less than 50 m or more than 50 ppm.

Comparative Example 2 In Example 2, the content of Si in the A-Si alloy was set to 20 pp.
An A-stabilized superconducting wire was produced in the same manner as in Example 2 except that the amount was less than 40 m or more than 40 ppm.

Comparative Example 3 In Example 1, 99.9993% was used instead of the A-Zn alloy.
A-stabilized superconducting wire was manufactured in the same manner as in Example 1 except that high-purity A was used.

Comparative Example 4 In Comparative Example 3, Cu was used in the same manner as in Comparative Example 3 except that high-purity Cu having 99.9998% purity was used instead of high-purity A.
A stabilized superconducting wire was manufactured.

With respect to each A-stabilized superconducting wire thus obtained, a current was gradually increased in a liquid He (4.2 K) while applying a magnetic field of 5 T, and the resistance was 10 ⁻¹¹ Ωcm. The critical current value (I _C ) at the time when the _temperature reached was measured for a short material having a length of 1 m. The A-stabilizing material of each A-stabilized superconducting wire was measured for 0.2% proof stress and RRR at 4.2K.

Also, a magnet having an inner diameter of 20 mm and an outer diameter of 50 mm was prepared using the superconducting wire, and the quench current and the maximum generated magnetic field were measured. This magnet is designed to generate a 5T magnetic field when 580 A is energized. The results are shown in Table 1.

As is clear from Table 1, the product of the present invention is I _C of the short member is equivalent to the conventional material (Comparative Example 4), which magnet properties when wound magnets become a greater than conventional material Was.

This is because when the 0.2% proof stress of the A stabilizing material at a very low temperature is not less than a predetermined value (3 kgf / mm ² ), the conductor is not deformed by electromagnetic force, and the RRR is extremely high and the electrical stability is excellent.

In contrast Comparative Examples 1 to 3, since the 0.2% proof stress or RRR of A stabilizing material is below the limit value of the present invention, although I _C of the short member is equivalent conventional materials (Comparative Example 4), a magnet The characteristics were inferior to those of conventional materials, and the design values of the magnet could not be cleared.

〔effect〕

As described above, the A-stabilized superconducting wire of the present invention has excellent strength and thermoelectric properties. For example, when this is used for a magnet conductor, high magnet properties are obtained, and industrially remarkable effects are obtained. Play.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H01B 12/00-13/00 565

Claims (1)

(57) [Claims] An aluminum-stabilized superconducting wire comprising a single-core or multi-core superconducting wire in which a superconducting core material is embedded in a copper or copper alloy matrix and an outer periphery of which is coated with an aluminum material as a stabilizing material. Aluminum stabilizing material of stabilized superconducting wire,
A-Zn with a 0.2% proof stress at cryogenic temperatures of 3 kg / mm ² or more, a residual resistance ratio (electric resistance ratio at 300K and 10K) of 700 or more, containing 30 to 50 ppm of Zn, and the balance of A
An aluminum-stabilized superconducting wire comprising an alloy or an A-Si alloy containing 20 to 40 ppm of Si and the balance being A.