JPH0525565A - High purity cu alloy for stabilizing material for superconducting use having high residual resistance value - Google Patents

Abstract

PURPOSE:To obtain the Cu alloy by incorporating specific amount of Zr into high purity copper whose oxygen content and purity are regulated to a specific value or below and a specific value or above, respectively. CONSTITUTION:Zr is incorporated as alloy component by 1-15ppm into high purity copper having <=1ppm oxygen content and >=99.998 purity. As compared with Zr-free high purity copper, this Cu alloy has by far the highest residual resistance value by the presence of Zr and can produce superior properties when used as stabilizing material for superconducting wire. In the above- mentioned alloy, when oxygen content exceeds 1ppm and purity is below 99.998% and further Zr content is outside the above range, the desired high residual resistance value cannot be obtained in respective cases.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-purity Cu alloy having a high residual resistance ratio and exhibiting excellent performance particularly when it is used as a stabilizer for superconducting wires which require this characteristic. is there.

In the past, for example, in the fields of particle accelerators, linear motor power, and electric power storage devices, a large number of filament core wires made of Nb-Ti alloy or the like are bundled with a stabilizing material made of high-purity copper interposed therebetween. The multi-conductor superconducting wire is used.

In the above-mentioned stabilizer for superconducting wire, when the superconducting state is broken in some part of the wire due to some external factor, the part is transformed into normal conducting, and accordingly Joule heat is generated. However, in addition to absorbing this heat, it also has the function of returning to the superconducting state by cooling it with the surrounding liquid helium, and also has the bypass function of the current that should flow to the core wire of the heat generating part.

When the above-mentioned stabilizer has an electrical resistivity at room temperature of ρ _273k and an electrical resistivity at liquid helium temperature of ρ _4.2k , the ratio of these is ρ _273k / ρ _4.2k (this It is also known that the higher the residual resistance ratio, the better the performance as a stabilizer.

Further, as a stabilizing material for the superconducting wire,
For example, as described in Japanese Patent Application Laid-Open No. 2-122037, the oxygen content is set to 1 to 50 ppm or less and 99.9.
It is also known that high-purity copper having a purity of 95% or more is used.

[0006]

On the other hand, in recent years, the high performance, high output, and high capacity of the above various mechanical devices are remarkable, and accordingly, the superconducting wire is also required to have high performance. At the present time, a high residual resistance ratio is also required for the stabilizing material to be formed.

[0007]

The inventors of the present invention have conducted research to develop a material having a high residual resistance ratio from the above viewpoints. As a result, the oxygen content has been reduced to 1 ppm or less, A high-purity Cu alloy in which 1 to 15 ppm of Zr is contained as an alloy component in high-purity copper having a purity of .998% or more is higher than a high-purity copper that does not contain Zr due to the inclusion of Zr as an alloy component As a result, we obtained a research result that it has a much higher residual resistance ratio and exhibits excellent performance when used as a stabilizer for superconducting wires.

The present invention has been made based on the above-mentioned research results, and is 1 to 15 ppm as an alloy component in high-purity copper having an oxygen content of 1 ppm or less and a purity of 99.998% or more. Containing Zr,
High-purity Cu for superconducting wire stabilizer having high residual resistance ratio
It is characterized by alloys.

In the high-purity Cu alloy of the present invention, the oxygen and Zr contents and the purity excluding the Zr component are limited as described above because the oxygen content is 1 pp.
Even if it exceeds m or the purity is less than 99.998%, the Zr content is less than 1 ppm, or 15
This is because when the content exceeds ppm, the desired high residual resistance ratio cannot be obtained.

Next, the high-purity Cu alloy of the present invention will be specifically described with reference to examples. Using an electric furnace, N ₂ + CO
In the reducing gas atmosphere, high-purity copper is dissolved, and in a state where the oxygen content and the purity of the high-purity copper are adjusted in the atmosphere, a predetermined amount of Zr is added and contained as an alloy component, and then diameter: 70 mm × Length: cast into an ingot with a diameter of 150 mm, cut out a rectangular piece with a cross-sectional dimension of 25 mm x 25 mm, and hot-roll it at 850 ° C to obtain a diameter of 8 m.
A hot-rolled wire having a diameter of 0.5 mm is formed by cold rolling from this hot-rolled wire, and subjected to strain relief annealing at 500 ° C. for 1 hour. High purity C of the present invention with purity, oxygen and Zr content
u alloy wire rods 1 to 7 and comparative wire rods 1 to 5 were manufactured.

[0011]

[Table 1]

The comparative wires 1 to 5 have at least one of purity, oxygen content and Zr content outside the scope of the present invention. In addition, the numbers in parentheses in the Purity column of Table 1 indicate the purity when Zr is excluded.

Next, the high purity C of the present invention obtained as a result of the above
Regarding the u alloy wire rods 1 to 7 and the comparative wire rods 1 to 5, the room temperature electric resistivity (ρ _273k ) and the electric resistivity at liquid helium temperature (ρ _4.2k ) were measured by the four-terminal method, and the residual resistance ratio was calculated. Calculated. The measurement results are shown in Table 1.

[0014]

From the results shown in Table 1, the high-purity Cu alloy wire rods 1 to 7 of the present invention have much higher residual resistance than the comparative wire rod 1 having the composition corresponding to the above-mentioned conventional high-purity copper. It is clear that it has a ratio, while the comparison wire 2
~ 5, purity, oxygen content, and Zr
It is clear that if any of the contents is out of the range of the present invention, ρ _4.2k becomes particularly high and the desired high residual resistance ratio is not exhibited.

As described above, the high-purity Cu alloy of the present invention has a high residual resistance ratio due to Zr contained as an alloy component. Therefore, when it is used as a stabilizer for superconducting wires, It has industrially useful characteristics such as contributing to further improvement of the performance of the superconducting wire.

Claims (1)

Claims: 1. An oxygen content of 1 ppm or less, 9
A high-purity Cu alloy for superconducting stabilizer having a high residual resistance ratio, which is obtained by containing 1 to 15 ppm of Zr as an alloy component in high-purity copper having a purity of 9.998% or more.