JPS63294615A - Compound superconduction stabilizing thin plate and its manufacture - Google Patents

Abstract

PURPOSE:To enable a compound superconduction stabilizing thin plate having a wide width costlessly by providing a copper-tin or copper-gallium alloy layer, a superconductor layer composed of niobium or niobium-titanium or vanadium, and a stabilizing metal layer composed of metal good conductors of copper, silver, aluminum etc. CONSTITUTION:Niobium (or niobium containing a small quantity of titanium) 2' and 3' are explosively bonded in both sides of a copper-tin (tin density of 5-15 weight %) alloy 1'. Or vanadium is explosively bonded in both sides of a copper-gallium alloy (gallium density of 10-20 atomic density). Furthermore, metal good conductors 4, and 5, for stabilizing of copper, silver, aluminum, etc. are explosively bonded in both sides of a cladding material of niobium/ copper-tin/niobium or vanadium/copper-gallium/vanadium formed in the first process. This enables a large thin plate to be easily obtained and a compound superconduction stabilizing thin plate obtained which has a good adherence between a superconduction layer and each stabilizing metal layer, and a good electric and thermal conductivity between the superconduction layer and the stabilizing metal layers.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a compound superconducting stabilized thin plate and a method for producing the same.

[Prior art] In recent years, the number of devices that use large superconducting magnets, such as nuclear magnetic resonance tomography devices and superconducting magnet devices for pulling single crystals, has been increasing. It is used as a component. Furthermore, there is a fear that the leakage magnetic field from large magnets as described above may have an adverse effect on surrounding electronics and living things.

Magnetic shielding using iron or magnetic metal is of course possible in order to shield these unnecessary magnetic fields, but the walls must be extremely thick, often exceeding the load capacity of the floors in hospitals and laboratories.

By the way, since a superconductor is a diamagnetic substance, it is known that the rear of the superconductor can be efficiently shielded from a magnetic field by forcibly bending the lines of magnetic flux.

The following methods are conventionally known as methods for manufacturing compound superconducting thin plates that can be used for such purposes. For example, in the case of Nb3Sn, ■Nb thin plates are immersed in a tin solution to adhere tin to the surface. A method in which copper foil is soldered to both surfaces of Nb3Sn by reaction heat treatment in an inert atmosphere at around 950°C to generate Nb3Sn at the boundary between Nb and tin; ■ Copper-tin round bar, niobium pipe, copper pipe In this order, the composite pellets arranged coaxially from the center are extruded, processed by wire drawing, etc., then flat rolled to form a thin plate, which is then heat treated in a vacuum or inert atmosphere at a temperature of around 750°C to produce niobium A method of reacting and producing Nb3Sn at the interface between copper and tin alloy.

In the case of V3Ga, vanadium and gallium can be used instead of tin in each of the above methods.

[Problems to be Solved by the Invention] In the conventional method as described above, in the former method, it is not easy to immerse a large amount of niobium in a tin bath or to heat treat it to make it pliable. Moreover, it is not practical to solder a wide copper foil, and the equipment for carrying out the soldering is large-scale and expensive. Furthermore, the latter method is unsuitable for manufacturing wide thin plates. In other words, in order to obtain sufficient adhesion, it is necessary to increase the processing rate from billet to flat rolling, and for this reason, the diameter of the billet immediately before flat rolling has to be reduced, and as a result, the diameter of the billet just before flat rolling has to be reduced. There were limits to what you could get.

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the prior art and provide an inexpensive and wide compound superconducting stabilized thin plate and a method for manufacturing the same.

[Means for Solving the Problems] In order to achieve the above object, the compound superconducting stabilizing thin plate according to the present invention is made of copper-tin (tin concentration 5 to 15% by weight).
or copper-gallium (gallium concentration 10-20 at%)
an alloy layer, and a superconductor made of niobium, niobium-titanium (titanium concentration 0.1 to 2 at%), or vanadium, which is explosively deposited on both sides of this metal layer and forms a superconductor intermetallic compound boundary layer together with the alloy layer. and a stabilizing metal layer made of a good metal conductor such as copper, silver, aluminum, etc. on both sides, which is explosively bonded or press-bonded to the outside of each superconductor layer, and is processed to the required thickness and heat-treated. P! It is characterized by being formed as a thin plate.

According to another feature of the present invention, the method for manufacturing a compound superconducting stabilized thin plate includes niobium or niobium-titanium (titanium concentration 0%) on both sides of a copper-tin (tin concentration 5-15% by weight) alloy.
．． By explosively bonding a superconductor (1 to 2 atomic%) and further bonding or pressure-welding a good stabilizing metal conductor such as copper, silver, or aluminum to both outer sides of the superconductor, these copper-tin alloys and niobium mana or niobium are bonded. The superconductor and the stabilizing metal good conductor are firmly bonded to each other, and the five-layer body thus obtained is processed to a desired thickness by forging, rolling or other machining, and then heated at a temperature of 500°C to 750°C. 30 minutes ~ 200
It consists of a time heat treatment.

According to yet another feature of the invention, the method for producing the compound superconducting stabilizing thin plate comprises copper-gallium (gallium concentration 10-2
By explosively bonding a vanadium superconductor on both sides of the alloy (0 atomic%) and then explosively bonding or pressure-bonding a stabilizing metal good conductor such as copper, silver, or aluminum to both outer sides, these copper-gallium alloys and vanadium The superconductor and the stabilizing metal good conductor are firmly bonded to each other, and the five-layer body thus obtained is processed to a desired thickness by forging, rolling or other machining, and then heated at a temperature of 71,500°C to 750°C for 30 minutes. minutes ~ 2
00 hours of heat treatment.

Preferably, the thickness ratio of the alloy or superconductor to the stabilizing metal good conductor may be selected in the range of 1:1 to 1:20.

[Function] According to the method of the present invention, in the first step, niobium (or niobium containing a small amount of titanium) is explosively deposited on both sides of a copper-tin (tin concentration: 5 to 15% by weight) alloy. . Alternatively, vanadium is explosively deposited on both sides of a copper-gallium base metal (gallium concentration 10 to 20 H%). In the second step, a good stabilizing metal conductor such as copper, silver, or aluminum is further explosively bonded to both sides of the niobium/copper-tin/niobium or vanadium/copper-gallium/vanadium clad material formed in the first step. .

In the above process, the good conductor (#l, !, aluminum, etc.) and the copper-tin or copper-gallium alloy must not come into direct contact next to each other. This is to prevent the electrical conductivity and thermal conductivity of the good conductor from decreasing due to diffusion.

The thus obtained five-layer clad material, for example, copper/niobium/copper-tin/niobium/I, is machined by forging, rolling, etc. to a desired thickness, for example, 0.05 to 1 Ill+.
is formed. Although it is necessary to perform several annealing operations during this processing step, it is necessary to carry out intermediate annealing at a temperature at which a niobium-tin reaction does not occur at the interface between the niobium and the copper-tin alloy.

The five-layer clad sheet processed to the desired temperature is subjected to a reaction heat treatment in vacuum or in an inert atmosphere at a temperature of 500°C to 150°C for 30 minutes to 200 hours, thereby forming the niobium and copper-tin interface. niobium-tin undergoes a diffusion reaction to form a superconducting intermetallic compound Nb3Sn.

Note that by using vanadium instead of copper-tin or niobium, v3Ga can be obtained instead of NbSn.

[Examples] Examples of the present invention will be described below with reference to the accompanying drawings.

1 and 2 show an embodiment of the method according to the present invention, in which niobium plates 2.3 with a thickness of 1 round are first bombarded on both sides of a tin alloy plate 1 with a thickness of 1.7+m@-13% by weight. A 200 x 300 m thick plate was formed by explosively bonding 4.5 copper plates each having a thickness of 10 m on both sides of the plate.

This thick plate is repeatedly rolled and intermediately annealed to a thickness of 1
m, formed into a thin plate of Fuku 200 m, and then I
Heat treatment was performed at 700° C. for 24 hours in a vacuum of −5 Torr or higher. As a result, as shown in FIG. 2, a copper-13% by weight tin alloy layer 1', niobium layers 2' and 3', and a copper layer 4
', 5', and the copper-13 superimposed pyrotin alloy layer 1' and each niobium layer 2', 3'.
Sn! A compound superconducting stabilized thin plate consisting of 6.7 was obtained. In this case, the thickness of each Nb3Sn layer 6.7 produced by the reaction was 5 to 10 μm.

A sample with a width of 5 m and a length of 50 m was made from the thus obtained wide thin plate, and its superconducting critical current density was measured at 4.2 m in a magnetic field, and the results shown in the following table were obtained.

Next, an example of use of the compound superconducting stabilizing thin plate constructed in this manner will be described.

First, to explain the case of using it as a magnetic shielding body with reference to FIG. 3, the thin compound superconducting stabilizing plate produced according to the above embodiment is cut out to form a disk 8 with a diameter of 10 aa, and this is immersed in liquid of 4.2. The disk 8 was placed in helium, and a magnetic field was applied perpendicularly to the disk 8 using a superconducting magnet 9 for applying a magnetic field. Hall elements 10 are attached to the front and back of this disk 8.
11 and measured the magnetic field, the magnetic field behind the disk was zero until the magnetic field in front exceeded 0.5T. This means that the Nb3Sn compound thin plate manufactured according to the example was able to provide magnetic shielding up to a magnetic field of 0.5T. In these examples the thickness of the copper layer is an important factor (0.04 m+ in the final state in the example above);
The thickness must be optimal so that the superconductor operates in a magnetically stable manner. In the above example, the thin plate serving as the shield body was immersed in liquid helium at step 4.2, but since Nb3Sn has a superconducting critical temperature Tc of 17° to 18°, it must be cooled using a refrigerator. It is also possible to configure it like a magnetic shield panel.

Further, FIGS. 4 to 6 show an example of manufacturing a superconducting magnet using the compound superconducting stabilizing thin plate of the present invention.

In the example shown in Fig. 4, the wide thin plate of the present invention is slit to a width of 5 to 10 m to form a tape-like strip, and the tape-like strip is wound in layers like a pancake as shown in the figure to form a unit magnet. A solenoid magnet is constructed by forming a module and stacking a plurality of unit magnet modules.

In the example shown in FIG. 5, the thickness of the stabilizing metal good conductor is maximized to form a large current wide superconducting magnet that can operate at a large current density (10^/am2 or more).

Furthermore, in the example shown in FIG. 6, a unit disk of a tutar-shaped magnet is manufactured by cutting out the compound H conductive cover plate of the present invention as shown in the figure, and a plurality of disks are stacked to form a continuous current path. A bitter type magnet is constructed by electrical connection.

[Effects of the Invention] As explained above, according to the present invention, the central alloy, the superconducting alloy bodies on both sides, and the good conductors (stabilizing metals) such as copper, silver, and aluminum on the outside can be exploded. After bonding by bonding, pressure welding, etc., the rolling process begins, so that it can be processed based on a sufficiently large explosion-bonded five-layer clad plate (or block), and large thin plates can be easily obtained. The adhesion between the layer and each stabilizing metal layer (JF, )a is very good, and since no solder is used, the conduction of electricity and heat between the superconductor layer and the stabilizing metal layer is good.
Therefore, the compound superconducting stabilizing thin plate according to the present invention is an inexpensive and effective means for magnetic field shielding, and can be operated at high current densities when used to construct a superconducting magnet.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view showing each member constituting the compound superconducting stabilizing thin plate according to the present invention, FIG. 2 is a partially enlarged sectional view showing the structure of the compound superconducting stabilizing thin plate formed by the method of the present invention, and FIG. 3 to 6 are schematic diagrams showing different examples of use of the compound superconducting stabilizing thin plate according to the present invention. In the figure 1': Copper-13 layered tin alloy layer 2', 3': Niobium layer 4', 5': f! 4th layer 6.7: NbaSn layer 1 Figure 13 Figure 4 Figure 5 Figure 6 Figure

Claims (1)

[Claims] 1. A copper-tin (tin concentration: 5 to 15% by weight) or copper-gallium (gallium concentration: 10 to 20 atomic%) alloy layer, which is explosively deposited on both sides of this metal layer, A superconductor layer consisting of niobium, niobium-titanium (titanium concentration 0.1 to 2 at%), or vanadium, which together form a superconductor intermetallic compound boundary layer, and a superconductor layer that is explosively bonded or pressure-welded to the outside of each superconductor layer. 1. A compound superconducting stabilizing thin plate comprising a stabilizing metal layer made of a good metal conductor such as copper, silver, or aluminum, processed to a required thickness and heat treated to form a five-layer thin plate. 2. The compound superconducting stabilizing thin plate according to claim 1, wherein the thickness ratio of the inner alloy layer and superconductor layer to the outer stabilizing metal layer is 1:1 to 1:20. . 3. Superconductors of niobium or niobium-titanium (titanium concentration 0.1 to 2 at%) are explosively bonded to both sides of the copper-tin (tin concentration 5 to 15% by weight) alloy, and copper and silver are further deposited on both sides of the alloy. The copper-tin alloy, the niobium or niobium-titanium superconductor, and the stabilizing metal good conductor are firmly bonded to each other by explosive bonding or pressure welding with a good stabilizing metal conductor such as aluminum. Manufacture of a compound-based conductive stabilized thin plate characterized by processing a five-layer body to a desired thickness by forging, rolling or other machining, and then heat-treating it at a temperature of 500°C to 750°C for 30 minutes to 200 hours. Law. 4. The method for producing a compound superconducting stabilized thin plate according to claim 3, wherein the thickness ratio of the alloy or superconductor to the stabilizing metal good conductor is in the range of 1:1 to 1:20. 5. A vanadium superconductor is explosively bonded to both sides of the copper-gallium (gallium concentration 10 to 20 at%) alloy, and a good stabilizing metal conductor such as copper, silver, or aluminum is bonded or pressure-bonded to both outer sides of the superconductor. By this, the copper-gallium alloy, the vanadium superconductor, and the stabilizing metal good conductor are firmly bonded to each other, and the five-layer body thus obtained is processed to a desired thickness by forging, rolling, or other machining. A method for producing a compound superconducting stabilized thin plate, which is then heat-treated at a temperature of 500°C to 750°C for 30 minutes to 200 hours. 6. The method for producing a compound superconducting stabilized thin plate according to claim 5, wherein the thickness ratio of the alloy or superconductor to the stabilizing metal good conductor is in the range of 1:1 to 1:20.