JPH09120720A - Auxiliary superconductive composite wire and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the quality of a superconductive composite wire by forming a conductor as initial winding from Ag-Au-Mn alloy, thereby heightening the mechanical strength of the initial winding conductor to ensure enhancement of the yield and the easiness in works, and also reducing the thermal conductivity. SOLUTION: An auxiliary superconductive composite wire for use as a reserve consists of a laminate 4 of superconductive element wires 1 of such a structure that a metal film 3B is provided on the peripheral surface of a superconductive core 3A made of a superconductive material. An initial winding conductor 2 made of Ag-Au-An alloy is wound on the periphery of this laminate 4 at a certain pitch, followed by fixation and a prescribed heat treatment, and thus the intended superconductive composite wire is obtained. The Au and Mn contents of the conductor 2 should be 0.01-30at.% and 0.01-5at.%, respectively, and thereby the low thermal conductivity and tensile strength are improved. This should enhance the quality of the resultant composite wire, give a good yield, and improve the easiness in works of initial winding.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a preliminary superconducting composite wire,
And a method for manufacturing a superconducting composite wire, in particular, a preliminary superconducting composite wire in which the mechanical strength of a wound conductor wire is increased to improve yield and workability, and the thermal conductivity is reduced to improve quality, and a superconducting composite wire. The present invention relates to a method for manufacturing a composite wire.

[0002]

2. Description of the Related Art As a conventional method for manufacturing a superconducting composite wire,
For example, there is one disclosed in Japanese Patent Laid-Open No. 4-334820.

In this superconducting composite wire manufacturing method, first, a plurality of sheet-shaped superconducting element wires each having a metal coating on the outer periphery of a superconducting material are superposed to form a laminated body, and then the laminated body is manufactured. A superconducting composite wire is obtained by winding a small-diameter winding conductive wire made of Ag around the outer periphery to fix the laminated body, and finally performing heat treatment.

[0004]

However, according to the conventional method for manufacturing a superconducting composite wire, since the winding wire for fixing the laminated body is made of soft Ag, the winding wire is not wound during winding and after heat treatment. There is a risk that it may break, resulting in a decrease in yield and workability. Further, when low intrusion heat is required for the superconducting composite wire, Ag has a very high thermal conductivity, so that heat may intrude through Ag and deteriorate the quality.

Therefore, an object of the present invention is to improve the mechanical strength of the wound wire to improve the yield and workability, and at the same time, to reduce the thermal conductivity and improve the quality, and a superconducting composite wire and a superconducting wire. A method of manufacturing a composite wire is provided.

[0006]

In view of the above problems, the present invention improves the mechanical strength of wound wires to improve yield and workability, and reduces thermal conductivity to improve quality. The present invention provides a preliminary superconducting composite wire in which a wound copper wire is composed of an Ag-Au-Mn alloy.

Further, the method for producing a superconducting composite wire of the present invention which achieves the above object, comprises forming a metal coating on the outer periphery of a superconducting material to form a superconducting element wire, and laminating a plurality of superconducting element wires. Forming a wire laminated body, winding a wound copper wire made of an Ag-Au-Mn alloy around the outer periphery of the superconducting element wire laminated body to form a preliminary superconducting composite wire, and subjecting the preliminary superconducting composite wire to a predetermined heat treatment. Has become.

In the above Ag-Au-Mn alloy, Au
Content of 0.01 to 30 at% and Mn content of 0.
It is preferably from 01 to 5 at%.

When the wound conductor wire is made of an Ag-Au-Mn alloy, the inclusion of Au improves the low thermal conductivity and the inclusion of Mn enhances the mechanical strength. Here, the reason for setting the content of Au in the range of 0.01 to 30 at% is that the effect of improving the low thermal conductivity is not obtained when the content is 0.01 at% or less, and the effect becomes flat when the content exceeds 30 at%. is there. Further, the content of Mn is 0.01
The reason for setting the content to 5 at% is that there is no effect of improving the tensile strength if the content is 0.01 at% or less, and the tensile strength decreases conversely if the content exceeds 5 at%, and the elongation increases by 1% up to 5 at%. If it exceeds that, it will hardly grow. In addition, Mn also plays a role of re-strengthening the alloy material by internally oxidizing and dispersing and strengthening the alloy after heat treatment.

The cross-sectional area of the winding wire is 0.01 to
A range of 20 mm ² is preferred. Set the cross-sectional area of the winding wire to 0.
The reason why it is set to 01 to ²⁰ mm ² is that the conductive wire is apt to break at 0.01 mm ² or less, and the heat penetration amount becomes large at 20 mm ² or more. Further, the winding pitch of the winding conductor wire is appropriately in the range of 5 to 50 mm. Furthermore, as the shape of the winding conductor wire, a round wire shape or a tape shape can be applied.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION A preliminary superconducting composite wire and a method for producing a superconducting composite wire according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows the structure of a preliminary superconducting composite wire according to the first embodiment of the present invention. This preliminary superconducting composite wire is a spare part of the superconducting composite wire, and is formed by laminating a plurality of superconducting element wires 1 each having a metal coating 3B on the outer periphery of a superconducting core 3A made of a superconducting material. The superconducting composite wire comprises a body 4 and a winding wire 2 wound around the outer circumference of the superconducting element wire laminated body 4 at a predetermined pitch and made of an Ag-Au-Mn alloy for fixing them. Becomes

In the wound conductor wire 2, the Au content is 0.
01-30at%, Mn content is 0.01-5at%
It is preferred that The content of Au is 0.01 to 30
The reason for setting the range of at% is that the effect of improving the low thermal conductivity is not obtained when the content is 0.01 at% or less, and the improvement does not occur when the content exceeds 30 at%. The reason for setting the Mn content to 0.01 to 5 at% is that the effect of improving the tensile strength is not obtained when the content is 0.01 at% or less, and the tensile strength is decreased on the contrary when it exceeds 5 at% ( See FIG. 2).

The method of manufacturing the superconducting composite wire will be described in detail below with reference to FIG. First, Bi ₂ S as a superconducting material
A metal coating 3B made of Ag is applied to the outer periphery of a superconducting core 3A made of r ₂ Ca ₁ Cu ₂ O _x to have a thickness of 0.5 mm,
A superconducting element wire 1 having a width of 5 mm is manufactured.

Next, 10 superconducting element wires 1 thus obtained are laminated into a conductor shape to form a superconducting element wire laminated body 4. afterwards,
Ag-10 at% Au-2a having a cross-sectional area of 1 mm ^2.
A winding wire 2 of a round wire of t% Mn alloy is wound at a pitch of 10 m.
A preliminary superconducting composite wire (FIG. 1) is formed by winding the superconducting wire laminated body 4 around the outer periphery of the superconducting element laminated body 4 with m.

Finally, this preliminary superconducting composite wire was first heated in air to 855 ° C., kept constant for 10 minutes, then gradually cooled at 10 ° C./h, and further heated at 840 ° C. for about 10 hours. After holding the temperature constant for about 10 hours, a heat treatment for cooling the furnace was carried out for each to produce a Bi ₂ Sr ₂ Ca ₁ Cu ₂ O _x oxide superconducting composite wire.

On the other hand, as a comparative example, Ag-10 at% Au.
A winding wire made of pure Ag and a winding wire made of pure Ag are respectively wound around the outer circumference of the superconducting element wire laminate 4, and heat treated in the same manner to obtain a Bi ₂ Sr ₂ Ca ₁ Cu ₂ O _X oxide superconducting composite wire. Each was manufactured.

FIGS. 2 and 3 show a wound conductor wire made of Ag-10 at% Au-2 at% Mn alloy of the first embodiment and a wound conductor wire 2 made of Ag-10 at% Au alloy of the comparative example.
And the thermal conductivity and tensile strength characteristics of the pure Ag winding wire.

As can be seen from these figures, in terms of thermal conductivity (FIG. 2), the wound conductor wire according to the first embodiment does not decrease in resistivity even when the temperature is low, and the thermal conductivity increases. It is suppressed. On the other hand, the wound conductor wire of the comparative example does not have a resistivity comparable to that of the wound conductor wire of the first embodiment, and in particular, the pure silver wire has a drastic decrease in resistivity at low temperature. , The thermal conductivity is high. Also in the tensile strength characteristics (FIG. 3), the wound conductor wire of the first embodiment has much higher tensile strength than the wound conductor wire of the comparative example.

Further, in the superconducting composite wire manufactured according to the first embodiment, Mn in the Ag-10 at% Au-2 at% Mn alloy of the wound conductive wire is internally oxidized at the time of heat treatment to disperse the alloy. It was confirmed that the winding wire was strengthened and the winding wire was strengthened again. On the other hand, the wound conductor wire of the comparative example was not dispersion strengthened.

The preliminary superconducting composite wire of the first embodiment described above is constructed by laminating 10 superconducting element wires and winding the winding wire around the superconducting element wire, but about 10 sets of superconducting composite wires are combined. When manufacturing such a large-scale superconducting composite conductor, the diameter of the wound conductor wire should be 5 to improve the strength.
It is necessary to make it about mm. At this time, invasion heat increases, and an alloy having a large amount of Mn, for example, Ag-30 at% Au-5, is used to improve low thermal conductivity so as to prevent this.
It is preferable to use an at% Mn alloy.

[0022]

As described above, according to the preliminary superconducting composite wire and the method for manufacturing the superconducting composite wire of the present invention, since the Ag-Au-Mn alloy is used for the wound copper wire, the mechanical strength of the wound wire is improved. The strength can be increased to improve the yield and workability during winding, and the thermal conductivity can be reduced to improve the quality of the superconducting composite wire.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a graph showing the relationship between the Mn content in the wound wire and the tensile strength.

FIG. 3 is a graph showing the thermal conductivity of a wound conductor wire.

FIG. 4 is a graph showing the tensile strength characteristics of a wound wire.

[Explanation of symbols]

 1 superconducting element wire 2 winding wire 3A superconducting core 3B metal coating 4 superconducting element laminated body

Claims (4)

[Claims] 1. A spare superconducting composite wire, which is a spare part of a superconducting composite wire, wherein a bundle of a plurality of superconducting element wires is secured to a bundle by winding a copper wire around the outer periphery of the bundle. The attached copper wire is made of an Ag-Au-Mn alloy, and is a wound conductor wire for a superconducting collective conductor. 2. The Ag-Au-Mn alloy has an Au content of 0.01 to 30 at% and a Mn content of 0.01.
The method for producing a superconducting collective conductor according to claim 1, wherein the superconducting collective conductor has a content of 5 at%. 3. The wound copper wire is 0.01 to ²⁰ mm ²
The method for producing a superconducting collective conductor according to claim 1, having a cross-sectional area of 4. A superconducting wire is formed by forming a metal coating on the outer periphery of a superconducting material, and a plurality of superconducting element wires are laminated to form a superconducting element wire laminated body. A method for producing a superconducting composite wire, comprising winding a wound copper wire made of an Ag-Au-Mn alloy to form a preliminary superconducting composite wire, and subjecting the preliminary superconducting composite wire to a predetermined heat treatment.