JPH06314609A - Abacuo based superconducting coil and its manufacture - Google Patents

Abstract

PURPOSE:To provide the structure of a superconducting coil wherein the reduction ratio of critical current density can be made small when a superconducting tape is worked into a coil, and critical current density is large. CONSTITUTION:A superconducting tape 2 is constituted by forming an ABaCuO based oxide superconducting layer 5 on a base member 3 of a metal tape, via an intermediate layer 4. The title superconducting coil 1 is constituted by working the superconducting tape 2 into a coil. The tape 2 is worked by a radius of curvature wherein the strain loaded on the oxide superconducting layer 5 is 0.25% or larger. The tape 2 is so worked that the oxide superconducting layer 5 is positioned inside the base member. The above ABCuO based superconducting coil is characterized by that compression stress is loaded on the oxide superconducting layer 5. In the composition formula, A shows one kind or two kinds or more out of Y and rare earth elements.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of an ABaCuO-based superconducting coil which is known to have a high critical temperature and a method for manufacturing the same, and a superconducting coil of this kind includes a superconducting magnet, a superconducting energy storage device and a superconducting coil. Applied development is underway in fields such as power generation.

[0002]

2. Description of the Related Art Conventionally, a superconducting tape has been formed by forming an oxide superconducting layer on a base material by a film forming method such as a laser vapor deposition method or a CVD method. Then, the thin-film superconducting layer formed by this type of film-forming method is a type obtained by filling a copper pipe with powder of the constituent elements of the oxide superconductor, subjecting it to a diameter reduction process, and further subjecting it to heat treatment. It is known to have a higher critical current density (Jc) than superconducting conductors. In addition, this type of superconducting tape is also considered to have a low rate of deterioration of superconducting properties due to a magnetic field when a magnetic field is applied after cooling to a superconducting state by cooling at liquid nitrogen temperature (77K). Attempts have been made to manufacture a compact and lightweight superconducting magnet by subjecting a coil to the superconducting tape of.

However, when the oxide superconducting layer is directly formed on a long base material such as a metal tape, the metal tape is a polycrystal, and the crystal structure of the metal tape is the crystal structure of the oxide superconductor. However, since the crystal orientation is not uniform, the crystal orientation of the oxide superconducting layer formed on it is also disordered, and in the oxide superconducting layer with disordered crystal orientation, However, there is a problem that good superconducting characteristics cannot be obtained. In addition, since the thermal expansion coefficient of the metal tape and that of the oxide superconductor are greatly different, thermal strain due to the difference in thermal expansion coefficient is accumulated during the heating / cooling process during the heat treatment for forming the oxide superconducting layer. As a result, cracks may occur in the oxide superconducting layer in some cases, and there is a problem that the critical current density is significantly reduced. Furthermore, during the heat treatment, if an element diffusion phenomenon occurs between the metal tape and the oxide superconducting layer, some of the constituent elements of the metal tape enter the oxide superconducting layer side or the oxide superconducting layer. Therefore, there is a problem that the composition of the oxide superconducting layer is destroyed and the superconducting characteristics are deteriorated, because a part of the constituent elements of (3) is diffused to the metal tape side.

Therefore, conventionally, an intermediate layer having a superior crystal orientation on a metal tape, for example, an intermediate layer having a crystal structure similar to that of an oxide superconductor such as MgO, SrTiO ₃ , or yttrium-stabilized zirconia (YSZ). Is formed and an oxide superconducting layer is formed on this intermediate layer, whereby an oxide superconducting layer having excellent crystal orientation is formed on a long base material such as a metal tape. If such an intermediate layer is formed between the metal tape and the oxide superconducting layer,
Since the accumulation of thermal strain due to the difference in thermal expansion coefficient can be mitigated and the element diffusion between the oxide superconducting layer and the metal tape can be suppressed, the superconducting tape provided with the oxide superconducting layer having excellent characteristics. Can be obtained.

[0005]

Therefore, the present inventors have found that
An intermediate layer of yttrium-stabilized zirconia (YSZ) is formed on a metal tape made of hastelloy, and YBaCu, which is excellent in stability among oxide superconductors, is formed on the intermediate layer.
A superconducting tape was manufactured by forming an O-based superconducting layer, and the superconducting tape was coiled. First, a metal tape made of Hastelloy having a width of 10 mm and a thickness of 0.1 mm is used, and the thickness of the metal tape is 0.1 mm.
A 5 μm YSZ intermediate layer is formed by a sputtering apparatus, and a thickness of about 1.
An oxide superconducting layer having a composition of 0 μm Y ₁ Ba ₂ Cu ₃ O _7-x was formed to obtain a superconducting tape. The critical current density (Jc) of this superconducting tape shows a value of 1 × 10 ⁴ A / cm ² under the conditions of liquid nitrogen temperature (77K) and magnetic field of 0 Tesla, especially in the linear state without coiling. It was

Next, a plurality of these samples were prepared, coiled with various bending radii, and the critical current density was measured for each of the obtained coils under the conditions of liquid nitrogen temperature (77 K) and magnetic field of 0 Tesla. Is shown in FIG. In addition,
At the time of coiling, the coiling was performed by winding the base material on the inside and the oxide superconducting layer on the outside with respect to a winding cylinder having a predetermined diameter. Furthermore, the strain applied to the oxide superconducting layer with various bending radii is
It was calculated from the following formula. {D / (2r + d)} × 100 = strain (%) However, in this formula, d represents the value of the thickness of the intermediate layer, and r represents the value of the bending radius. The vertical axis of FIG. 5 represents the critical current density Jc of the superconducting tape before coiling.
The value of the ratio Jc / Jc (0) of both is shown as (0), where Jc is the critical current density when a predetermined strain is applied. Therefore, when the strain is 0, that is, in the linear state where the superconducting tape is not coiled, the data is 1.00.
Is shown.

As is clear from the results shown in FIG. 5, the change state of the critical current density when the coil processing is performed shows that the rate of decrease in the critical current density is small up to a strain of 0.2%. When the strain exceeds 0.2%, it begins to decrease greatly, and when the strain exceeds 0.25%, it falls below 80% of the sample that has not been coiled. When the strain is 0.3%, it is before coiling. There was a problem that the critical current density was reduced to 50% or less.

The present invention has been made in view of the above circumstances, and provides a structure of a superconducting coil having a high critical current density, which can reduce a decrease rate of the critical current density even when the superconducting tape is coiled. And a method for manufacturing a superconducting coil.

[0009]

In order to solve the above-mentioned problems, a superconducting tape comprising an ABaCuO-based oxide superconducting layer formed on a base material of a metal tape via an intermediate layer. Is a superconducting coil formed by coiling, wherein strain applied to the oxide superconducting layer is 0.25.
%, The superconducting tape is coiled with a radius of curvature of not less than%, the superconducting tape is coiled so that the oxide superconducting layer is positioned inside the base material, and the oxide superconducting layer is subjected to compressive stress. It is a thing. However, in the above composition formula, A represents one or more of Y and rare earth elements.

In order to solve the above-mentioned problems, the invention according to claim 2 is the superconducting coil according to claim 1, wherein the strain ε applied to the oxide superconducting layer during coil processing is defined as the strain calculated by the following equation. It was done. ε = {d / (2r + d)} × 100 However, in the above formula, d represents the thickness of the base material, and r represents the bending radius.

In order to solve the above-mentioned problems, the invention according to claim 3 has an ABaC layer on a base material of a metal tape via an intermediate layer.
When the superconducting tape formed by forming the uO-based oxide superconducting layer is coiled and the strain applied to the oxide superconducting layer itself is 0.25% or more, the oxide superconducting layer is used as a base material. The coil is processed so as to face the inside, and compressive stress is applied to the oxide superconducting layer.

In order to solve the above problems, the invention according to claim 4 is to calculate the strain ε applied to the oxide superconducting layer during the coil processing according to claim 3 by the following formula. ε = {d / (2r + d)} × 100 However, in the above formula, d represents the thickness of the base material, and r represents the bending radius.

[0013]

When a superconducting tape having a base material, an intermediate layer, and an ABaCuO-based superconducting layer is coiled and the strain applied to the superconducting layer exceeds 0.25%, the oxide superconducting material is placed inside the base material. When the superconducting tape is coiled so that the layers are positioned, a compressive stress can be applied to the oxide superconducting layer during coiling, whereby a tensile stress can be prevented from acting on the oxide superconducting layer.
By applying the compressive stress in this way, it is possible to suppress a decrease in the critical current density of the oxide superconducting layer during coil processing.
In the calculation of the strain ε during coiling, ε = {d / (2r +) where d is the thickness of the base material and r is the bending radius.
It is preferable to apply the distortion calculated by the equation d)} × 100. The strain of the superconducting layer can be easily grasped by this calculation formula, and the strain at the time of coil processing can be grasped by the magnitude of the value to form the coil without lowering the critical current density of the oxide superconducting layer. .

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1A shows a schematic structure of an embodiment of a superconducting coil manufactured by carrying out the method of the present invention.
(B) shows a partial cross-sectional structure of the superconducting coil 1 of this embodiment. As shown in FIG. 1A, the superconducting coil 1 is constructed by winding a superconducting tape 2 in a coil shape, and the superconducting tape 2 of this example has a base material 3 made of a metal tape and one surface of the base material 3. It is mainly composed of the coated intermediate layer 4 and the oxide superconducting layer 5. In practice, when the superconducting tape 2 is wound in multiple layers, an interlayer insulating layer may be arranged together with the superconducting tape 2 for the purpose of performing insulation treatment for each layer, or the superconducting characteristics may be stabilized when energized. A tape made of a conductive copper stabilizing material is wound together with the superconducting tape 2 to form a coil. In this embodiment, members such as an insulating tape and a stabilizing base material tape are omitted.

The substrate 3 is made of silver, platinum, stainless steel,
It consists of a long metal tape such as copper or hastelloy. The intermediate layer 4 is made of YSZ, MgO, SrTiO ₃
Made of materials such as. The material forming the intermediate layer 4 is preferably similar to the crystal structure of the oxide superconducting layer 5 to be used, and is preferably close to the thermal expansion coefficient of the oxide superconducting layer 5. The intermediate layer 4 is provided between the base material 3 and the oxide superconducting layer 5 so as not to come into direct contact with each other, and the crystal structure of the oxide superconducting layer 5 formed thereon is It is for adjustment. By providing this intermediate layer 4, the difference in the coefficient of thermal expansion between the two is relaxed to eliminate the thermal strain, element diffusion between the base material 3 and the oxide superconducting layer 5 is suppressed, and the intermediate layer 4 is formed. By epitaxially growing the oxide superconducting layer 5 by the film forming method, the crystal orientation of the oxide superconducting layer 5 can be adjusted.

The oxide superconducting layer 5 is made of A ₁ Ba ₂ Cu ₃
It is composed of a thin film of an oxide superconductor represented by a composition formula of O _7-x . Here, A is Y and a rare earth element (L
a, Ce, Pr, Nd, Pm, Sm, Eu, Gd, T
b, Dy, Ho, Er, Tm, Yb, Lu), or one or more elements selected from the group.

The superconducting tape 2 is coiled with the oxide superconducting layer 5 facing inward and the substrate 3 facing outward. Therefore, compressive stress is applied to the oxide superconducting layer 5 in a coiled state.

The coiling of the superconducting tape 2 can be easily carried out, for example, by winding the oxide superconducting layer 5 around the outer periphery of the cylindrical body 6 as shown in FIG. 1 (a). In this case, the oxide superconducting layer 5 is wound so as to be positioned inside the base material 3. As a result, compressive stress can be applied to the oxide superconducting layer 5, and a decrease in the critical current density of the oxide superconducting layer 5 due to the compressive stress can be suppressed. When the superconducting tape 2 is coiled so that the oxide superconducting layer 5 is located outside the base material 3 by reversing the above relationship, tensile stress acts on the oxide superconducting layer 5 to lower the critical current density. However, if the bending radius is small, the rate of decrease in the critical current density is small.

Next, an example of an apparatus and method for forming the intermediate layer 4 and the oxide superconducting layer 5 on the base material 3 will be described.
In this example, the intermediate layer 4 is formed on the base material 3 using the sputtering apparatus shown in FIG. This sputtering apparatus includes a base 11 that holds a base material 3 and a plate-shaped target 12 that is disposed diagonally above the base 11 so as to face each other with a predetermined gap.
And a target holder 1 for holding this target 12.
3 and the target 1 below the target 12.
Sputtering beam irradiation device 1 arranged toward the lower surface of 2
4 is the main component.

The apparatus of this embodiment is housed in a vacuum container (not shown) so that the surroundings of the base material 3 can be kept in a vacuum atmosphere. Further, an atmosphere gas supply source such as a gas cylinder is connected to the vacuum container, the inside of the vacuum container is in a low pressure state such as vacuum, and argon gas or another inert gas atmosphere or an inert gas containing oxygen. It can be adjusted appropriately according to the atmosphere.

In this example, since a long metal tape is used as the base material 3, the metal tape feeding device 15 and the winding device 16 are provided inside the vacuum container, and the feeding device 15 is provided.
So that the tape-shaped base material 3 is continuously fed out onto the base 11 and then wound by the winding device 16 so that a polycrystalline thin film can be continuously formed on the tape-shaped base material 3. It is configured.

The base 11 is provided with a heater inside so that the base material 3 sequentially fed onto the base 11 can be heated to a desired temperature. The target 12 is
It is for forming a target polycrystalline thin film, and the same or similar composition to the polycrystalline thin film having a target composition is used. Specifically as the target 12, M
Zirconia stabilized with gO or Y ₂ O ₃ (YS
Z), MgO, SrTiO ₃ or the like can be appropriately used, but the present invention is not limited to these, and a target suitable for the polycrystalline thin film to be formed may be used.

The sputter beam irradiation device 14 ionizes a part of atoms or molecules generated from the evaporation source housed inside, and controls the ionized particles by an electric field generated by an extraction electrode to form an ion beam. The irradiation device is a device that can irradiate the target 12 with ions to knock out the constituent particles of the target 12.

Next, an example of an apparatus for forming the oxide superconducting layer 5 will be described. FIG. 3 shows an example of an apparatus for forming an oxide superconducting layer by a film forming method, and FIG. 3 shows a laser vapor deposition apparatus. Laser vapor deposition apparatus 30 of this example
Has a processing container 31, and a substrate 3 and a target 33 can be installed in a vapor deposition processing chamber 32 inside the processing container 31. That is, a base 34 is provided at the bottom of the vapor deposition processing chamber 32, the base material 3 can be installed on the upper surface of the base 34, and the base 34 is supported diagonally above the base 34 by a support holder 36. The target 33 is provided in an inclined state. The processing container 31 has an exhaust hole 37.
It is connected to a vacuum exhaust device (not shown) via the so that the inside pressure can be reduced.

The target 33 has a composition similar to or close to that of the oxide superconducting layer 5 to be formed, or a sintered body of a complex oxide containing a large amount of components that easily escape during film formation or oxide superconducting. It consists of a plate such as a body. The base 34 has a built-in heater so that the substrate 3 can be heated to a desired temperature. Further, an atmosphere gas supply source such as a gas cylinder is connected to the processing container 31, the inside of the processing container 31 is in a low pressure state such as vacuum, and the atmosphere of argon gas or another inert gas atmosphere or an inert gas containing oxygen. It can be adjusted to an active gas atmosphere.

On the other hand, a laser emitting device 38, a first reflecting mirror 39, a condenser lens 40 and a second reflecting mirror 41 are provided on the side of the processing container 31, and a laser beam generated by the laser emitting device 38 is provided. The target 33 can be focused and irradiated through the transparent window 42 attached to the side wall of the processing container 31. The laser emitting device 38 is the target 33.
If it is possible to knock out the constituent particles from
Any of AG laser, CO ₂ laser, excimer laser, etc. may be used.

Next, an intermediate layer 4 of YSZ is formed on the base material 3 by using the sputtering apparatus shown in FIG. 2, and then an oxide is formed on the intermediate layer 4 by using the laser vapor deposition apparatus shown in FIG. The case of forming the superconducting layer 5 will be described. In order to form the YSZ intermediate layer 4 on the substrate 3, a target 12 made of YSZ is used. Further, the inside of the container accommodating the base material 3 is evacuated to create a reduced pressure atmosphere. Then, the sputter beam irradiation device 14 is operated, and the substrate 3 is sent from the sending device 15 onto the base 11 at a predetermined speed.

When the target 12 is irradiated with ions from the sputter beam irradiation device 14, the constituent particles of the target 12 are knocked out and fly onto the moving base material 3. Then, the constituent particles struck from the target 12 are deposited on the base material 3. By performing such sputtering, the intermediate layer 4 made of a polycrystalline thin film of YSZ is formed on the base material 3.
Can be formed.

As described above, the YSZ intermediate layer 4 is formed on the substrate 3.
, The oxide superconducting layer 5 is formed on the intermediate layer 4.
To form. In order to form the oxide superconducting layer 5 on the intermediate layer 4, the laser vapor deposition apparatus 30 shown in FIG. 3 is used in this example. To this end, if the substrate 3 having the intermediate layer 4 formed thereon is taken out from the sputtering apparatus shown in FIG. 2, it is set in the delivery device 45 of the laser vapor deposition apparatus 30 shown in FIG. 3, and the vapor deposition processing chamber 32 is vacuum pumped. Decompress. Here, if necessary, an oxygen gas may be introduced into the vapor deposition processing chamber 32 so that the vapor deposition processing chamber 32 has an oxygen atmosphere. Further, after the heater of the base 34 is operated to heat the base material 3 to a desired temperature, the base material 3 is sent out from the delivery device 45 and moved onto the base 34.

Next, the laser beam generated from the laser emitting device 38 is focused and irradiated on the target 33 in the vapor deposition processing chamber 32. As a result, the constituent particles of the target 33 are scooped out or evaporated and the particles are deposited on the intermediate layer 4. Simultaneously with the deposition, the deposited particles are heated to a predetermined temperature on the base 34, gradually cooled after passing through the base 34, and then wound up by the winding device 46, and the oxide superconducting layer 5
Becomes If necessary, after depositing the particles, the oxide superconducting layer 5 may be subjected to a desired heat treatment to adjust the crystal structure of the oxide superconducting layer.

During the film formation or the heat treatment, the substrate 3, the intermediate layer 4 and the oxide superconducting layer 5 are heated and cooled, so that thermal strain may act between the layers. Since the intermediate layer 4 is interposed between the oxide superconducting layer 3 and the oxide superconducting layer 5, the accumulation of thermal strain is reduced, and element diffusion between the base material 3 and the oxide superconducting layer 5 does not occur.
The composition of the oxide superconducting layer 5 does not collapse. Therefore, the superconducting tape 2 having excellent superconducting properties can be obtained, and if the superconducting tape 2 is used for coil processing as described above, the superconducting coil 1 shown in FIG. 1 can be obtained.

The superconducting tape 2 has an intermediate layer 4 between a base material 3 and an oxide superconducting layer 5, and inherently has high superconducting properties. Therefore, if the superconducting tape 2 is coiled by the above-described method, compressive stress can be applied to the oxide superconducting layer 5, so that an excellent oxide superconducting coil 1 can be obtained without lowering the critical current density. it can. The reason why the oxide superconducting layer 5 having excellent critical current characteristics is obtained is that if a tensile stress is applied to the oxide superconducting layer 5, defects such as microcracks are introduced into the oxide superconducting layer 5. However, there is a possibility that the introduction of this defect will significantly reduce the critical current density of the oxide superconducting layer 5, but when compressive stress is applied, the defect may be introduced. It is due to the small number. Therefore, by superposing the oxide superconducting layer 5 inside, coiling and applying compressive stress, the superconducting tape 2 having a high critical current density can be obtained.

(Manufacturing Example) The sputtering apparatus having the structure shown in FIG. 2 was used, and the inside of the vacuum container of this sputtering apparatus was evacuated by a vacuum pump to reduce the pressure to 3.0 × 10 ⁻⁴ Torr.
As the base material, a Hastelloy C276 tape having a width of 10 mm, a thickness of 0.1 mm and a length of 10 cm was used. Target is Y
Using SZ (stabilized zirconia), the sputtering voltage was set to 1000 V and the sputtering current was set to 100 mA, and sputtering was performed on the substrate to form a 0.5 μm thick YSZ film-shaped intermediate layer.

Next, an oxide superconducting layer having a thickness of 1 μm was formed on the YSZ intermediate layer by using a laser vapor deposition apparatus having the structure shown in FIG. As a target, Y _0.7 Ba _1.7 Cu
_A target made of an oxide superconductor having a composition of _3.0 O _7-x was used. In addition, the inside of the vapor deposition processing chamber is set to 200 mTorr
The pressure was reduced to 1, and laser deposition was performed at room temperature. An ArF laser with a wavelength of 193 nm was used as a laser for target evaporation. Then, the obtained tape was heat-treated at 400 ° C. for 60 minutes in an oxygen atmosphere to obtain an oxide superconducting tape. The oxide superconducting tape obtained has a width of 5.0 m.
m, 10 cm in length.

The oxide superconducting tape was cooled and the critical temperature and the critical current density were measured. As a result, the critical temperature = 9.
The value was 0 K, and the critical current density was 1 × 10 ₄ A / cm.

Next, a plurality of these superconducting tapes were prepared, and the superconducting tapes were coiled with various bending radii, and the critical current density was measured for each superconducting coil obtained under the conditions of liquid nitrogen temperature (77K) and magnetic field of 0 Tesla. Figure 4 shows the result
Shown in. For comparison, FIG. 4 also shows the critical current characteristics of the conventional superconducting tape shown in FIG. In addition, at the time of coiling, the superconducting tape was wound and coiled so that the base material was located inside and the oxide superconducting layer was located outside with respect to the winding cylinder having a predetermined diameter. The strain applied to the oxide superconducting layer with various bending radii was calculated from the following calculation formula. {D / (2r + d)} × 100 = strain (%) However, in this formula, d represents the value of the thickness of the intermediate layer, and r represents the value of the bending radius. Here, for example, the outer diameter is 16.6 cm
When the coil processing of winding the superconducting tape around the wound copper is applied to the wound copper, the strain ε applied to the oxide superconducting layer is
Is ε = {0.1 / (16.6 × 0.1)} × 100 = 0.
It becomes 3%.

As is clear from the results shown in FIG. 4, when the tensile strain exceeds 0.25%, the conventional example breaks 80% of the sample before coiling at the critical current density. When a tensile strain exceeds 0.3%, there arises a problem that the sample becomes 50% of the sample before coiling. On the other hand, in the superconducting coil coiled by the method according to the present invention, the critical current density does not decrease until the compressive strain reaches 0.3%, but rather the critical current density improves slightly. I was able to confirm that I am doing. From the above, it has been clarified that the superconducting coil manufactured by the method of the present invention has a smaller reduction rate of the critical current density than the conventional one even when coiled with a large curvature. Therefore, it was found that the superconducting coil can be obtained by carrying out the method of the present invention without lowering the critical current density.

In the above example, the case where the intermediate layer 4 is formed by the sputtering device and the oxide superconducting layer 5 is formed by the laser vapor deposition device has been described.
Alternatively, it is needless to say that the intermediate layer 4 and the oxide superconducting layer 5 may be continuously formed using either one of the laser vapor deposition devices, and other methods such as the CVD method and the vacuum vapor deposition method,
Various methods such as an electron beam vapor deposition method, a screen printing sintering method, a plasma spray method, and a molecular beam epitaxy method may be used. Then, even when these various intermediate layers 4 or oxide superconducting layers 5 are formed, the same as in the above case by coiling the superconducting tape 2 so that the oxide superconducting layers 5 are arranged inside. Thus, a superconducting coil in which the critical current density is not lowered can be obtained. Further, in the above-mentioned example, an example in which the oxide superconducting layer 5 has a composition of Y _0.7 Ba _1.7 Cu _3.0 O _7-x is described, but the oxide superconducting layer 5 is made of another system. Needless to say, may be used. So, for example, Y
Alternatively, a rare earth metal such as La or Ce may be used, or two or more of these elements may be used in combination, and one of the elements A of the composition formula A ₁ Ba ₂ Cu ₃ O _7-x may be used. The parts may be appropriately replaced with these elements before use.

[0039]

As described above, according to the present invention,
A superconducting tape having a base material, an intermediate layer, and an ABaCuO-based superconducting layer is coiled, and the oxide superconducting layer has a strain of 0.
In the case of more than 25%, if the superconducting tape is coiled with the oxide superconducting layer positioned inside the base material, a compressive stress can be applied to the oxide superconducting layer during coiling. This makes it possible to prevent tensile stress from acting on the oxide superconducting layer. By thus applying the compressive stress during coil processing, it is possible to suppress a decrease in the critical current density of the oxide superconducting layer during coil processing. Therefore, according to the present invention, it is possible to obtain a superconducting coil that exhibits excellent superconducting characteristics without a decrease in critical current density.

In the calculation of the strain ε during coiling, ε is the bending radius when d is the thickness of the substrate.
= {D / (2r + d)} × 100 The strain that is applied to the oxide superconducting layer during coil processing can be easily calculated and understood by calculating the strain using the formula: The present invention can be easily applied to a superconducting coil.

[Brief description of drawings]

FIG. 1 (a) is a perspective view showing a superconducting coil according to the present invention obtained by coiling a superconducting tape, FIG.
FIG. 1B is a cross-sectional view showing a part of the superconducting tape forming the superconducting coil shown in FIG.

FIG. 2 is a configuration diagram showing an example of a sputtering apparatus used for forming an intermediate layer such as YSZ on a base material such as a metal tape.

FIG. 3 is a configuration diagram showing an example of a laser vapor deposition apparatus used for forming an oxide superconducting layer on a substrate having an intermediate layer.

FIG. 4 shows the critical current densities obtained when a superconducting tape obtained by forming an intermediate layer and an oxide superconducting layer on a substrate is coiled with various curvatures by the conventional method and the method of the present invention. It is a figure which shows the change of.

FIG. 5 shows a change in critical current density obtained when a superconducting tape obtained by forming an intermediate layer and an oxide superconducting layer on a substrate is coiled with various curvatures by a conventional method. It is a figure.

[Explanation of symbols]

 1 superconducting coil, 2 superconducting tape, 3 base material, 4 intermediate layer, 5 oxide superconducting layer, ε strain, d base material thickness, r bending radius,

Front page continued (72) Inventor Nobuyuki Tekata 1-5-1 Kiba, Koto-ku, Tokyo Fujikura Ltd. (72) Inventor Takashi Saito 1-1-5 Kiba, Koto-ku, Tokyo Fujikura Ltd. (72) Inventor, Satoshi Kono 1-5-1, Kiba, Koto-ku, Tokyo Inside Fujikura Stock Company

Claims (4)

[Claims] 1. A metal tape base material with an intermediate layer interposed therebetween.
A superconducting coil obtained by coiling a superconducting tape formed by forming a BaCuO-based oxide superconducting layer, wherein the superconducting tape has a radius of curvature such that strain applied to the oxide superconducting layer is 0.25% or more. An ABaCuO-based superconducting coil, characterized in that the superconducting tape is coiled, and the superconducting tape is coiled so that the oxide superconducting layer is located inside the substrate, and the oxide superconducting layer is subjected to compressive stress. However, in the above composition formula, A represents one or more of Y and rare earth elements. 2. The ABaCuO-based superconducting coil according to claim 1, wherein the strain ε applied to the oxide superconducting layer during coil processing is a strain calculated by the following formula. ε = {d / (2r + d)} × 100 However, in the above formula, d represents the thickness of the base material, and r represents the bending radius. 3. A metal tape base material with an intermediate layer interposed therebetween.
When a superconducting tape formed by forming a BaCuO-based oxide superconducting layer is coiled and the strain applied to the oxide superconducting layer itself is 0.25% or more, the oxide superconducting layer is used as a base material. A method for manufacturing an ABaCuO-based superconducting coil, which is characterized in that a coil is processed so as to face the inside and a compressive stress is applied to the oxide superconducting layer. However, in the composition formula, A represents one or more of Y and rare earth elements. 4. The method for manufacturing an ABaCuO-based superconducting coil according to claim 3, wherein the strain ε loaded on the oxide superconducting layer during coil processing is calculated by the following formula. ε = {d / (2r + d)} × 100 However, in the above formula, d represents the thickness of the base material, and r represents the bending radius.