JP2000034125A - Production of oxide superconductor and its connection - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an oxide superconductor having improved flexibility and critical current density, capable of being readily made into an extra fine state and performing superconducting connection by mixing a Bi-based oxide superconductor powder of a specific composition with Ag-based alloy powder in a prescribed ratio, packing the mixture into an Ag-based alloy base of specified composition, rolling and baking. SOLUTION: Bi-based oxide superconductor powder 24 is mixed with metal powder 25 in the weight ratio of h:1-h ((h) is 0.1-0.9) to give oxide superconducting raw material powder 23. The raw material powder 23 is packed into a base 21, an obtained superconducting material 26 is rolled and baked to give a superconducting wire 20 of filament structure. The composition of the metal powder 25 is AgaCubMc ((a) is 1, (b) is 0-1, (c) is 0-0.05 and M is a metal such as Ti, Zr, Hf, V, Nb, Ta, Cr, etc.). The composition of the superconducting powder 24 is Bi1PbuSrxCayCuzOvMt ((u) is 0-0.3, (x) is 0.8-1.2, (y) is 0.2-1.2, (z) is 0-2.0 and (t) is 0-0.05). The composition of the base 21 is AgdCueMf ((d)is 1, (e) is 0-9 and f is 0-0.05).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an oxide superconductor and a method for connecting the same, and more particularly to a method for manufacturing a wire or bulk using a Bi-based oxide superconductor and an oxide applicable to the method for connecting the same. The present invention relates to a method for manufacturing and connecting a superconductor.

[0002]

2. Description of the Related Art In general, in order to put an oxide superconducting wire into practical use as a coil or a cable conductor, the wire after firing (sintering) must be flexible and have a high critical current density (Jc) at a predetermined level. It is necessary to have In particular,
Various studies have been made on bismuth (Bi) -based oxide superconducting wires, and various production methods have been tried so far. For example, in order to satisfy the above requirements, attempts have been made to increase the number of wires in the wire or to increase the number of wires.

[0003] For example, FIG. 10 is a schematic view showing a method of multicore by a powder-in-tube method. First, a raw material powder 2 of an oxide superconducting material (oxide superconductor) is added to a pure silver pipe 1 as a base material. And thinned to a certain diameter by wire drawing to obtain a single core wire 3. Further, several to several tens of the single-core wires 3 are bundled and packed in another pure silver pipe 1, drawn again, and fired to form a superconducting wire 4 having a composite thin wire structure.

FIG. 11 shows a superconducting wire 4 manufactured as described above.
In this superconducting wire 4, superconducting wires 5 are interposed between silver materials of a pure silver pipe 1 having a multilayer structure.
Are mixed, and there is a problem that it is difficult to make ultrafine multi-core.

Further, in such a manufacturing method, there is a problem that the number of steps for increasing the number of cores is increased as compared with the production of the single core wire 3.

FIG. 12 is a schematic view showing a method of multilayering by the jelly roll method. A composite sheet 8 formed by laminating a silver sheet 6 and an oxide superconducting sheet 7 is spirally wound around a silver core material 9. The wire is wound in a shape, and after a wire drawing process, a finalizing process is performed to obtain a superconducting wire rod 10 having a multilayer structure.

FIG. 13 shows a superconducting wire 1 thus manufactured.
0 is a cross-sectional view, in which the superconducting wire 10 has a form in which the oxide superconducting sheet 7 is mixed in each layer between the silver materials of the silver sheet 6, and it is difficult to make the layers extremely thin between layers. There's a problem.

Further, in such a manufacturing method, there is a problem that the number of steps for multi-layering is increased.

Conventionally, superconductors have been mainly connected by a soldering method for wires and a superconducting paste for bulk materials. FIG. 14 is a schematic perspective view of a connection method for connecting the superconducting tape 11 by soldering, and FIG. 15 is a longitudinal sectional view of the same, in which a connecting member 12 made of silver or superconducting tape is passed between the superconducting tapes 11. Then, the superconducting tape 11 and the connecting member 12 are connected by the solder 13.

However, in such a connection method, there is a problem that a resistance is generated at the connection portion when the power is supplied because the connection portion by the solder 13 is not a superconducting connection. Therefore, when the number of connection portions is increased in order to make the wire longer, there is a problem that the generated resistance increases and energy loss due to heat generation increases.

FIG. 16 is a schematic perspective view of a method for connecting the superconducting bulks 14 with the superconducting paste 15, wherein the end faces of the superconducting bulks 14 are connected via the superconducting paste 15. FIG. 17 is a schematic perspective view of another method of connecting the superconducting bulk 14 with the superconducting paste 15, wherein the side surfaces of the superconducting bulk 14 are superconducting paste 1.
5 is connected.

However, the connection structure using the superconducting paste 15 has a problem in that the superconducting paste 15 contains an organic substance, so that the superconducting bulk 14 is adversely affected. In addition, there is a disadvantage that the connecting portion is weak in strength and the superconductivity is low.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and is an oxide superconductor having excellent flexibility and critical current density required for an oxide superconducting wire. It is an object of the present invention to provide a manufacturing method and a connection method.

Another object of the present invention is to provide a method of manufacturing an oxide superconductor and a method of connecting the same, which can easily realize ultra-fine multi-core and ultra-thin multilayer.

Another object of the present invention is to provide a method of manufacturing and a method of connecting an oxide superconductor which enables mutual superconducting connection between a wire and a bulk of the superconductor.

Another object of the present invention is to provide a method of manufacturing an oxide superconductor and a method of connecting the oxide superconductor, which can easily perform superconducting connection and have good orientation.

[0017]

That is, the present invention pays attention to the fact that a predetermined metal powder is mixed with an oxide superconducting powder, followed by firing, and that the superconductor grows into a filament by this firing. The first invention is a method for manufacturing an oxide superconductor in which an oxide superconductor is manufactured by firing an oxide superconductor raw material powder, wherein Bi is used as a raw material of the oxide superconductor. The oxide-based superconducting powder is adopted, and the Bi-based oxide-based superconducting powder is mixed with a metal powder to form the oxide-based superconducting raw material powder. In the manufacturing step of further firing, the composition of the metal powder is AgaCubMc, where a = 1,
b = 0 to 1, c = 0 to 0.05, M is a metal described below, and the composition of the Bi-based oxide superconducting powder is Bi1Pbu
SrxCayCuzOvMt, where u = 0 to 0.3,
x = 0.8-1.2, y = 0.2-1.2, z = 0
2.0, M is a metal described below, and the metal M is Ti,
Zr, Hf, V, Nb, Ta, Cr, Mo, W, B, M
g, Mn, Fe, Co, Ni, Zn, In, Sn, A
u, at least one of the elements
= 0 to 0.05 and t = 0 to 0.05, and the metal powder and the B
The weight mixing ratio with the i-based oxide superconducting powder is h: 1-h
Where h = 0.1 to 0.9, and the composition of the base material is AgdCueMf, where d = 1 and e = 0 to
9, f = 0 to 0.05, which is a method for producing an oxide superconductor.

The metal M is desirably contained in at least one of the metal powder, the Bi-based oxide superconducting powder, and the base material.

The metal M is desirably 0.001 to 0.5 in total with respect to Bi = 1 of the Bi-based oxide superconducting powder.

The second invention relates to a method of connecting oxide superconductors for connecting oxide superconductors produced by firing an oxide superconductor raw material powder, wherein the method comprises the steps of: A superconducting pellet is adopted as a connecting member to be interposed, and a metal powder is mixed with a Bi-based oxide superconducting powder as a pellet raw material of the superconducting pellet. The composition of the metal powder is AgaCubMc, where a = 1, b = 0 to 1, c = 0 to 0.05, M is a metal described below, and the composition of the Bi-based oxide superconducting powder is as follows:
Bi1PbuSrxCayCuzOvMt, where u = 0
~ 0.3, x = 0.8-1.2, y = 0.2-1.2,
z = 0 to 2.0, M is a metal described later, and the metal M
Are Ti, Zr, Hf, V, Nb, Ta, Cr, Mo,
W, B, Mg, Mn, Fe, Co, Ni, Zn, In,
A material containing at least one of Sn and Au in the range of c = 0 to 0.05 and t = 0 to 0.05 in total of at least one of the elements, and the metal powder And the Bi-based oxide superconducting powder has a weight mixing ratio of h:
1-h, where h = 0.1 to 0.9, and the superconducting pellets are formed into a predetermined shape, and are formed between the superconducting raw material of the oxide superconductor to be connected. A method for connecting an oxide superconductor, characterized in that the superconducting pellet is interposed and then fired together with the superconducting raw material.

The oxide superconductor to be connected is desirably manufactured by the manufacturing method according to the first invention.

In the method for manufacturing an oxide superconductor according to the present invention (first invention), a predetermined metal powder is mixed with the oxide superconductor powder and then fired, and the composition of the metal is changed as described above. Since it was a predetermined ratio, a small amount of a small amount of metal element diffused into the crystal of the oxide superconducting powder,
The superconducting conductor grows in the form of a filament to become a superconducting filament, and a continuous structure of a superfine superconducting conductor can be realized between metal elements, and multifilamentation can be easily performed as compared with the conventional manufacturing method. . Therefore, the flexibility and high critical current density required for the superconducting wire can be achieved.

Further, in the method for connecting an oxide superconductor according to the present invention (second invention), when connecting superconducting conductors such as a superconducting wire or a bulk, the superconducting pellet material of the connecting member between the superconducting conductors is used as a pellet raw material. Since a mixture of metal powder and Bi-based oxide superconducting powder similar to that of the first invention is employed, the superconducting conductor to be connected and the superconducting filament in the superconducting pellet form a superconducting connection structure by firing. A much more reliable superconducting connection structure can be realized as compared with the conventional solder connection method or superconducting paste connection method.

[0024]

Next, a method for manufacturing an oxide superconductor according to the present invention (first invention) will be described with reference to FIGS. However, the same parts as those in FIGS. 10 to 17 are denoted by the same reference numerals, and detailed description thereof will be omitted. FIG.
FIG. 2 is a cross-sectional view of the superconducting wire 20 manufactured according to the present invention, and FIG. 2 is a cross-sectional view of the superconducting wire 20 in the longitudinal direction.
In this embodiment, superconducting filaments 22 in a fine wire state are densely packed instead of superconducting wires 5 between base materials 21 corresponding to (FIG. 10).
In this case, a multifilamentary wire having a filament structure with a much higher density can be obtained as compared with the case (FIG. 11).

FIG. 3 is a schematic explanatory view of a method of manufacturing an oxide superconductor according to the present invention. In the present invention, a substrate 21 corresponding to a pure silver pipe 1 (FIG. 10) in a conventional manufacturing method is oxidized. Material superconducting raw material powder 23 is filled. The oxide superconducting raw material powder 23 is formed by mixing a specific metal powder 25 with a raw material powder of an oxide superconducting material (Bi-based oxide superconducting powder 24). The superconducting material 26 formed by filling the base material 21 with the oxide superconducting raw material powder 23 is subjected to a rolling process such as wire drawing and other spreading processes, and further, a superconducting oxide (superconducting wire 20) is formed by firing. .

By using Bi-based oxide superconducting powder 24 mixed with this specific metal powder 25 (oxide superconducting raw material powder 23), as shown in FIG. It is possible to obtain a multifilamentary wire having the same multifilamentary shape as that of the related art, which has grown into a fiber shape in the longitudinal direction of 20 and has a much higher density.

The composition of the metal powder 25 is AgaCubMc.
Where, as the atomic ratio (at%), a = 1 and b = 0
１1, c = 0０〜0.05, and M is a metal described below.

The composition of the Bi-based oxide superconducting powder 24 is B
i1PbuSrxCayCuzOvMt, where u = 0 to 0.3, x = 0.8 to 1.2, y = 0.
2 to 1.2, z = 0 to 2.0, and M is a metal described below.
The atomic ratio (v) of oxygen (O) can be arbitrarily adjusted because it changes depending on the firing conditions.

The metal M is Ti, Zr, Hf, V, Nb,
Ta, Cr, Mo, W, B, Mg, Mn, Fe, Co,
Any one or more of Ni, Zn, In, Sn, and Au are summed, and c = 0 to 0.05;
A material containing an amount in the range of = 0 to 0.05 is used.

Metal powder 25 and Bi-based oxide superconducting powder 2
4 is h: 1-h, where h = 0.
1 to 0.9.

The composition of the substrate 21 is AgdCueMf, where d = 1, e = 0-9, and f = 0 as atomic ratios.
0.05.

The metal M is desirably contained in at least one of the metal powder 25, the Bi-based oxide superconducting powder 24, and the substrate 21.

When the metal M is Bi-based oxide superconducting powder 2
It is desirable that the total value of Bi for Bi is 0.001 to 0.5.

In the method for producing an oxide superconductor according to the present invention, the reason that the superconducting crystal grows into a fiber shape to form the superconducting filament 22 is that the superconducting crystal is plate-shaped, This is because crystals are aligned in the longitudinal direction, and crystals are generated in the aligned state.

Further, the necessity of the metal M in the metal powder 25 will be described. A small amount of the small amount of the metal element M diffuses into the oxide crystal formed by the Bi-based oxide superconducting powder 24, and the crystal structure of the oxide crystal is partially disturbed. Quality) layer is generated and pins the magnetic flux lines that have penetrated into the superconductor. By this pinning action, the critical current density (Jc) characteristics are significantly improved. Therefore, if the amount of the element to be diffused into the crystal is too small, no amorphous layer is generated, and if it is too large, the entire crystal structure is disturbed and the superconductivity is lost.

Further, when the above-mentioned range is selected as an appropriate addition amount of the metal element M, the critical current density (Jc) characteristic becomes as shown in FIG. Is at least 1.3 times or more, and if it is large, it is about 3 times or more. In FIG. 4,
The ratio of each metal element M below Ti is 0.1 as an atomic ratio.

As an example, FIG. 5 shows the relationship between the content and the critical current density (Jc) when the metal element M is Ti. The content of Ti is determined by
This is represented by the atomic ratio of As shown in the figure, when the Ti content is 0.001 to 0.5, it is 1.3 times or more as compared with the case where no Ti is added.

The firing conditions in the present invention are as follows: a temperature of 800 to 900 ° C .;
At 0 hours, the total is 150 to 300 hours, and the atmosphere is an oxygen gas atmosphere of 5 to 100%. However, FIG.
5 and the above-described experiment in FIG. 5 were performed at a temperature of 827 ° C., a baking treatment time of 200 hours, and an oxygen gas atmosphere with O ₂ of 8%.

Next, a method for connecting an oxide superconductor according to the present invention (second invention) will be described with reference to FIGS. FIG. 6 is a perspective view illustrating a case in which superconducting bulks 30 of an oxide superconductor are connected to each other, and FIG.
FIG. 3 is a sectional view of the same, in which a superconducting pellet 31 is interposed between superconducting bulks 30.

As the pellet raw material for the superconducting pellets 31, an oxide superconducting raw material powder 23 obtained by mixing a metal powder 25 with a Bi-based oxide superconducting powder 24 similar to that of the first invention (FIG. 3) is employed. The superconducting pellet 31
This is formed into a predetermined shape. For example, the cross section has an “E” -shaped cross-section having engagement recesses 32 on both sides that can engage the ends of the superconducting bulk 30. The superconducting pellets 31 are placed between the superconducting raw materials of the superconducting bulk 30 to be connected.
Is lightly pressed and baked together with this superconductor raw material.

When the sintering process is performed in this manner, in the case of the connection process between the superconducting bulks 30, the superconducting pellets 31
Superconducting crystal grows in a filament shape (superconducting filament 33) and is integrated with the base material (superconducting bulk 30), so that a good superconducting connection structure can be realized.

FIG. 8 is a cross-sectional view showing a method of connecting the superconducting wires 40. In the superconducting wires 40, the raw material powder 2 of the oxide superconducting material is filled inside the pure silver pipe 1 (FIG. 10). It may be something. The superconducting pellets 31 are engaged between the superconducting wires 40, and a firing process is performed in a state where they are integrated, so that the superconducting wires 40 are formed.
The core (the raw material powder 2 of the oxide superconducting material) and the superconducting filament 33 of the superconducting pellet 31 are integrated, and the metal M contained in the superconducting pellet 31 and the pure silver pipe 1 are integrated.

FIG. 9 shows the superconducting bulk 30 and the superconducting wire 4.
0 is a cross-sectional view when connecting the superconducting bulk 30.
Superconducting pellets 5 interposed between the superconducting wires 40
0 is a bulk recess 51 that engages the superconducting bulk 30.
And the wire recesses 52 to be engaged with the superconducting wires 40 are respectively formed, and the superconducting bulk 30, the superconducting wires 40 and the superconducting pellets 50 are integrated and fired together as in the above-described connection method (FIGS. 7 and 8). You can connect after processing.

In the second invention, the oxide superconductor to be connected (superconducting bulk 30, superconducting wire 40)
Is desirably manufactured by the manufacturing method according to the first invention, but the present invention can be applied to any other manufacturing method.

[0045]

As described above, according to the present invention (first invention), it is possible to manufacture a multifilamentary wire, tape or bulk composed of an oxide superconducting material and a base material at a high density. As compared with the conventional manufacturing method, the number of cores can be easily increased, and a high critical current density can be obtained, so that high performance can be achieved. Further, according to the second aspect of the present invention, the superconducting pellets can be integrally connected together with the superconducting pellets regardless of the case of the superconducting bulk or the superconducting wire, and the superconducting connection work becomes easy.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a superconducting wire 20 manufactured by a method for manufacturing an oxide superconductor according to the present invention (first invention).

FIG. 2 is a cross-sectional view of the superconducting wire 20 in the length direction.

FIG. 3 is a schematic explanatory view of a method for manufacturing an oxide superconductor according to the present invention.

FIG. 4 shows the critical current density (J
It is a graph which shows the characteristic of c).

FIG. 5 is a graph showing the relationship between the content and the critical current density (Jc) when the metal element M is Ti.

FIG. 6 is a perspective view illustrating a case where superconducting bulks 30 are connected to each other in the method for connecting an oxide superconductor according to the present invention (second invention).

FIG. 7 is a sectional view of the same.

FIG. 8 is a cross-sectional view showing a method of connecting superconducting wires to each other.

FIG. 9 is a cross-sectional view when the superconducting bulk 30 and the superconducting wire 40 are connected.

FIG. 10 is a schematic view showing a conventional method of multicore by a powder-in-tube method.

FIG. 11 is a cross-sectional view of the manufactured superconducting wire 4;

FIG. 12 is a schematic view showing a conventional method of multilayering by a jelly roll method.

FIG. 13 is a cross-sectional view of the manufactured superconducting wire rod 10;

FIG. 14 is a schematic perspective view of a conventional connection method for connecting superconducting tape 11 by soldering.

FIG. 15 is a longitudinal sectional view of the same.

FIG. 16 is a schematic perspective view of a conventional method for connecting a superconducting bulk 14 with a superconducting paste 15;

FIG. 17 is a schematic perspective view of another conventional method for connecting a superconducting bulk 14 with a superconducting paste 15;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pure silver pipe 2 Raw material powder of oxide superconducting material 3 Single core wire 4 Superconducting wire of composite fine wire structure (Fig. 11) 5 Superconducting wire 6 Silver sheet 7 Oxide superconducting sheet 8 Composite sheet 9 Silver core material 10 Superconducting wire of multilayer structure ( 13) 11 Superconducting tape (FIG. 14) 12 Connecting member made of silver or superconducting tape 13 Solder 14 Superconducting bulk (FIG. 16) 15 Superconducting paste 20 Superconducting wire of filament structure (FIG. 1) 21 Substrate 22 Superconducting in a fine wire state Filament (FIGS. 1 and 2) 23 Oxide superconducting raw material powder (FIG. 3) 24 Bi-based oxide superconducting powder 25 Metal powder 26 Superconducting material 30 Superconducting bulk (FIG. 6) 31 Superconducting pellet (FIG. 6) 32 Superconducting pellet 31 Engagement recess 33 Superconducting filament 40 Superconducting wire (Fig. 8) 50 Superconducting pellet (Fig. 9) 51 Bulk recess of superconducting pellet 50 52 Wire recess of superconducting pellet 50

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 39/00 C04B 35/00 ZAAK (72) Inventor Masayuki Ishizuka 63-30 Yuigaoka, Hiratsuka-shi, Kanagawa Prefecture Sumitomo Shigeto Machinery Corporation Hiratsuka Office (72) Inventor Tomoyuki Yanagiya 63-30 Yuigaoka, Hiratsuka-shi, Kanagawa Prefecture Sumitomo Heavy Industries Machinery Corporation Hiratsuka Office (72) Inventor Yoshiaki Tanaka 1-2-1, Sengen, Tsukuba-shi, Ibaraki Within the National Institute for Metals Science and Technology (72) Inventor Tsuneo Kuroda 1-2-1 Sengen, Tsukuba City, Ibaraki Prefecture Within the National Institute for Metals Science and Technology (72) Inventor Yuji Abe 3-chome 19, Namekawakawacho, Hitachi City, Ibaraki Prefecture No. 5 Sukegawa Electric Industry Co., Ltd. (72) Inventor Kuniaki Miura 3-19-5 Namekawa Honcho, Hitachi City, Ibaraki Prefecture F-term (reference) in Kawasaki Electric Industry Co., Ltd. BA09 BA10 BA11 BA13 BA20 BC12 CA11 CA36 DA11 DA31 JA02 JA22 KA36 4M113 BA26 CA35 5G321 AA06 AA98 BA00 BA01 CA15 CA46 DA02 DA08 DB06 DB11 DB29 DB46 DB99

Claims (5)

[Claims] 1. A method for producing an oxide superconductor by firing an oxide superconducting raw material powder to produce an oxide superconductor, wherein a Bi-based oxide superconducting powder is used as a raw material for the oxide superconductor. A manufacturing process in which a metal powder is mixed with the Bi-based oxide superconducting powder to obtain the oxide superconducting raw material powder, and the base material is filled with the oxide superconducting raw material powder, spread, and further fired. In the above, the composition of the metal powder is AgaCubMc, wherein a
= 1, b = 0 to 1, c = 0 to 0.05, M is a metal described below, and the composition of the Bi-based oxide superconducting powder is Bi1PbuSr
xCayCuzOvMt, where u = 0 to 0.3, x =
0.8-1.2, y = 0.2-1.2, z = 0-2.
0 and M are metals described later, and the metal M is Ti, Zr, Hf, V, Nb, Ta, C
r, Mo, W, B, Mg, Mn, Fe, Co, Ni, Z
n = 0, 0.05, and t = 0 by summing at least one of n, In, Sn, and Au.
A material containing an amount in the range of 0.05 is used, and the weight mixing ratio of the metal powder and the Bi-based oxide superconducting powder is h: 1-h, where h = 0.1-0. 9,
Wherein the composition of the substrate is AgdCueMf, where d =
1. A method for producing an oxide superconductor, wherein e = 0 to 9 and f = 0 to 0.05. 2. The method according to claim 1, wherein the metal M is the metal powder,
The method for producing an oxide superconductor according to claim 1, wherein the oxide superconductor is contained in at least one of the i-based oxide superconducting powder and the base material. 3. The total content of the metal M is 0.001 to 0.5 with respect to Bi = 1 of the Bi-based oxide superconducting powder.
The method for producing an oxide superconductor according to claim 1, wherein 4. A method of connecting oxide superconductors for connecting oxide superconductors produced by firing an oxide superconducting raw material powder, wherein the connection member is interposed between the oxide superconductors to be connected. A superconducting pellet is used as a material. As a pellet raw material of the superconducting pellet, a metal powder is mixed with a Bi-based oxide superconducting powder.
= 1, b = 0 to 1, c = 0 to 0.05, M is a metal described below, and the composition of the Bi-based oxide superconducting powder is Bi1PbuSr
xCayCuzOvMt, where u = 0 to 0.3, x =
0.8-1.2, y = 0.2-1.2, z = 0-2.
0 and M are metals described below, and the metal M is Ti, Zr, Hf, V, Nb, Ta, C
r, Mo, W, B, Mg, Mn, Fe, Co, Ni, Z
n = 0, 0.05, and t = 0 by summing at least one of n, In, Sn, and Au.
A material containing an amount in the range of 0.05 is used, and the weight mixing ratio between the metal powder and the Bi-based oxide superconducting powder is h: 1-h, where h = 0.1-0. 9,
The superconducting pellets are formed into a predetermined shape, the superconducting pellets are interposed between the superconducting raw materials of the oxide superconductor to be connected, and then fired together with the superconducting raw materials. A method for connecting an oxide superconductor. 5. A method for connecting an oxide superconductor, wherein the oxide superconductor to be connected is manufactured by the manufacturing method according to claim 1.