CN117894548A

CN117894548A - Bi-2212 superconducting coil skeleton

Info

Publication number: CN117894548A
Application number: CN202410090256.XA
Authority: CN
Inventors: 陈文革; 俞雷; 赵航; 丁杭伟; 徐健源; 徐志鹏; 黄鹏程; 陈治友
Original assignee: Hefei Institutes of Physical Science of CAS
Current assignee: Hefei Institutes of Physical Science of CAS
Priority date: 2024-01-22
Filing date: 2024-01-22
Publication date: 2024-04-16

Abstract

The invention discloses a Bi-2212 superconducting coil framework, which comprises a winding framework, a fixed joint and a copper electrode, wherein two ends of the winding framework are respectively provided with a wire inlet slot and a wire outlet slot, and two ends of the winding framework are also provided with T-shaped grooves; and when the superconducting coil is subjected to heat treatment, the two ends of the winding framework are respectively connected with the fixed joints, and after the superconducting coil is subjected to heat treatment, the two ends of the winding framework are respectively connected with the copper electrodes. The invention has the advantages that the first T-shaped boss and the second T-shaped boss which can be embedded into the T-shaped grooves are respectively arranged on the winding framework, the fixed joint and the copper electrode, so that the wire head on the superconducting coil framework cannot be damaged in the process of replacing the fixed joint with the copper electrode during heat treatment.

Description

Bi-2212 superconducting coil skeleton

Technical Field

The invention relates to the technical field of superconducting coils, in particular to a Bi-2212 superconducting coil framework.

Background

The Japanese scientist at the end of the twentieth century found the Bi-Sr-Ca-Cu-O system, and found that three superconducting phases, 2201, 2212 and 2223, were obtained, respectively, as long as the composition and structure were different. The Bi-2201 superconducting transition temperature is about 20K, and is mainly used for researching the high-temperature superconducting mechanism. Bi-2223 superconductive transition temperature is about 110K, and has certain current-carrying performance at 77K. However, current technology can only produce Bi-2223 tapes due to the superconducting imaging mechanism.

Bi-2212 is used as a high-temperature superconducting material, has an extremely high upper critical field, and still has stronger current carrying performance under a high background field. Meanwhile, the Bi-2212 superconducting material is an isotropic material, which is beneficial to manufacturing of armored Cable conductors (Cable-In-Conduit Conductor, CICC). And Bi-2212 is prepared by a powder tubing method (PIT), has simple preparation process and lower cost, and is suitable for large-scale mass production. To date, bi-2212 is the only high temperature superconducting material capable of being prepared into isotropic multi-filament round wires, and is the only viable choice for future high-field fusion stacks and particle collimators magnets. In addition, the current medical magnet and scientific research magnet are made of low-temperature superconducting materials, the round line structure of Bi-2212 means that the magnets can be replaced by Bi-2212, and the performance can be further improved.

As with most superconducting materials, bi-2212 requires heat treatment to exhibit a superconducting phase. However, the heat treatment process of Bi-2212 is very different from other superconducting materials, and the heat treatment of Bi-2212 needs to be performed in a high-temperature high-pressure and oxygen-enriched environment, and has the advantages of more temperature steps and long time. Bi-2212 generally adopts a silver sleeve as a matrix material, and the cost of silver is lower than that of other oxygen-permeable metals. When the heat treatment temperature reaches 884 ℃, bi-2212 powder can be melted into liquid, the liquid Bi-2212 has stronger corrosiveness, can corrode surrounding silver matrix, and the superconductive phase can show dendritic growth in the recrystallization process, and can directly penetrate through matrix material and be exposed to the outside when serious, thereby contacting other external substances, and reducing the performance. In addition, the formation of Bi-2212 superconducting phase requires a certain amount of oxygen doping, but most of the metal substances are extremely reactive with the metal at high temperature, so that oxygen in the heat treatment furnace is consumed, and particularly copper materials frequently used as test electrodes consume oxygen and are liable to react with Bi-2212, so that copper is not generally heat-treated with Bi-2212. The core wire is ceramic after the Bi-2212 is heat treated, so that the manufacturing of the common Bi-2212 coil adopts a route of winding firstly and then reacting. In the low temperature test of the heat treated coil, a tab electrode is required to connect the current leads. Because oxygen-free copper has small resistance at low temperature and low price, oxygen-free copper is generally used as a joint electrode. However, copper material cannot be heat treated with the coil, so two kinds of frameworks are used in the Bi-2212 heat treatment, one for heat treatment and one for test. This means that after the coil has been heat treated, the two bobbins need to be exchanged and the bobbin is fixed, so that only the fixed joints of the protective wire ends in the bobbins need to be exchanged for copper electrodes. However, the wire ends of the superconducting coils after heat treatment are in a ceramic state and are extremely easy to damage, so that a superconducting coil framework which is not easy to damage the wire ends is needed.

Disclosure of Invention

The technical problem to be solved by the invention is how to prevent the damage of the wire ends on the superconducting coil framework.

In order to solve the technical problems, the invention provides the following technical scheme:

the Bi-2212 superconducting coil framework comprises a winding framework, a fixed joint and a copper electrode, wherein a wire inlet groove and a wire outlet groove are respectively formed in the two ends of the winding framework, and T-shaped grooves are formed in the two ends of the winding framework;

When the superconducting coil is subjected to heat treatment, two ends of the winding framework are respectively connected with the fixed joints, a first vertical wire slot communicated with the wire inlet slot or the wire outlet slot is formed in the fixed joints, and the fixed joints are also provided with first T-shaped bosses capable of being embedded into the T-shaped grooves;

After the superconducting coil is subjected to heat treatment, the two ends of the winding framework are respectively connected with the copper electrode, a second vertical wire slot communicated with the wire inlet slot or the wire outlet slot is formed in the copper electrode, and a second T-shaped boss capable of being embedded into the T-shaped groove is further arranged on the copper electrode.

According to the invention, the winding framework is provided with the grooves, the fixed connector and the copper electrode are respectively provided with the first T-shaped boss and the second T-shaped boss which can be embedded into the T-shaped grooves, so that the wire heads on the superconducting coil framework cannot be damaged in the process of replacing the fixed connector with the copper electrode during heat treatment.

Preferably, when a single-layer superconducting coil is wound, a spiral wire groove is further formed in the winding framework, and two ends of the spiral wire groove are respectively communicated with the wire inlet groove and the wire outlet groove.

Preferably, the wire inlet groove and the wire outlet groove are symmetrically arranged with the T-shaped groove along the central line of the winding framework.

Preferably, a chamfer is formed at the top of the copper electrode.

Preferably, the inner wall of the T-shaped groove is also provided with a threaded hole.

Preferably, the second T-shaped boss is provided with a through hole concentric with the threaded hole.

Preferably, the fixed joint is made of non-copper material.

Preferably, the fixed joint is made of nickel-based alloy.

Compared with the prior art, the invention has the beneficial effects that:

Drawings

FIG. 1 is a schematic diagram of a single layer superconducting coil former according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of another embodiment of a single layer superconducting coil former according to the present invention;

FIG. 3 is a schematic view of a single-layer bobbin according to an embodiment of the present invention;

FIG. 4 is a schematic view of a multi-layered superconducting coil former according to an embodiment of the present invention;

FIG. 5 is a schematic view of another construction of a multi-layered superconducting bobbin according to an embodiment of the present invention;

Fig. 6 is a schematic structural diagram of a multi-layer bobbin according to an embodiment of the present invention.

Detailed Description

In order to facilitate the understanding of the technical scheme of the present invention by those skilled in the art, the technical scheme of the present invention will be further described with reference to the accompanying drawings.

In the present application, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; the device can be mechanically connected, electrically connected and communicated; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present application, the terms "first," "second," and "second" are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated unless otherwise explicitly specified and defined. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

Referring to fig. 1 to 6, the present embodiment discloses a Bi-2212 superconducting coil skeleton, which comprises a winding skeleton 1, a fixed joint 2 and a copper electrode 3, wherein two ends of the winding skeleton 1 are respectively provided with a wire inlet slot 101 and a wire outlet slot 102, two ends of the winding skeleton 1 are respectively provided with a T-shaped groove 11, and the inner wall of the T-shaped groove 11 is also provided with a threaded hole 12.

When the superconducting coil is subjected to heat treatment, two ends of the winding framework 1 are respectively connected with the fixed connector 2, a first vertical wire slot 201 communicated with the wire inlet slot 101 or the wire outlet slot 102 is formed in the fixed connector 2, first T-shaped bosses 21 capable of being embedded into the T-shaped grooves 11 are formed in two ends of the fixed connector 2, and the wire inlet slot 101 and the wire outlet slot 102 are symmetrically arranged with the T-shaped grooves 11 along the central line of the winding framework 1.

Further, the fixed joint 2 is made of a non-copper material, and in this embodiment, the fixed joint 2 is made of a nickel-based alloy.

After the heat treatment of the superconducting coil, the two ends of the winding framework 1 are respectively connected with the copper electrode 3, a second vertical wire slot 301 communicated with the wire inlet slot 101 or the wire outlet slot 102 is formed in the copper electrode 3, a second T-shaped boss 31 capable of being embedded into the T-shaped groove 11 is further arranged on the copper electrode 3, a through hole 311 concentric with the threaded hole is formed in the second T-shaped boss 31, and specifically, the copper electrode 3 is fixed on the winding framework 1 through bolts passing through the through hole 311 of the second T-shaped boss 31 and being connected to the threaded hole 12 in the T-shaped groove 11.

And the top of the copper electrode 3 is provided with a chamfer for matching with a barre test rod in the later test.

Further, when the single-layer superconducting coil is wound, the winding framework 1 is further provided with a spiral groove 103, and two ends of the spiral groove 103 are respectively communicated with the wire inlet groove 101 and the wire outlet groove 102 and used for fixing the single-layer superconducting coil.

The working principle of the single-layer superconducting coil framework is as follows: during winding, a wire is wound in the spiral groove 103 on the winding framework 1, and extends out of the wire head along the wire inlet groove 101 and the wire outlet groove 102; then the first T-shaped boss 21 of the fixed joint 2 is horizontally moved towards the direction of the wire end and placed into the T-shaped groove of the winding framework 1, and the wire inlet groove 101 and the wire outlet groove 102 are symmetrically arranged along the central line of the winding framework 1 with the T-shaped groove 11, so that the wire end extending from the wire inlet groove 101 and the wire outlet groove 102 is just positioned in the first vertical wire groove 201 of the fixed joint 2 after the first T-shaped boss 21 of the fixed joint 2 is clamped in the T-shaped groove 11. During heat treatment, the silver wire wrapped with glass fiber cloth is wound around the joint of the first T-shaped boss 21 for one circle, so that the fixed joint 2 is ensured not to fall off in the opposite direction of translational entering. After the heat treatment, the wound silver wire is taken down, and the fixed joint 2 is translated out along the opposite direction. Then the copper electrode 3 is replaced, the copper electrode 3 is translated towards the position of the wire end in the same way as the connection fixing joint 2, and then is connected into the threaded hole 12 in the T-shaped groove 11 by a bolt passing through the through hole 311 of the second T-shaped boss 31, so that the copper electrode 3 is fixed on the winding framework 1. The installed coil also requires a curing process, which is not within the scope of the invention herein. During testing, the superconducting coil framework is only required to be installed in a barrel test sample rod.

The working principle of the multilayer superconducting coil framework is as follows: when the multi-layer coil is wound, a single-layer number of coils are selected as much as possible, so that the wire inlet groove 101 and the wire outlet groove 102 are arranged at two ends of the winding framework 1, the barre test rod is conveniently utilized for testing, and no extra current lead is needed. The wire inlet grooves 101 and the wire outlet grooves 102 of the multilayer coil are not on the same cylindrical surface, so that wire grooves with different depths are formed in the winding framework 1 and are used for wire inlet and wire outlet respectively. The fixed joint 2 and the winding framework 1 are respectively provided with wire grooves which are the same as the wire inlet groove 101 and the wire outlet groove 102 on the winding framework 1. In the same way, the step of replacing the fixed joint 2 with the copper electrode 3 and the step of mounting and testing are identical to the working principle of the single-layer superconducting coil skeleton described above.

According to the invention, the T-shaped groove 11 is formed on the winding framework 1, the fixed joint 2 and the first T-shaped boss 21 and the second T-shaped boss 31 which can be embedded into the T-shaped groove 11 are respectively arranged on the copper electrode 3, so that the wire heads on the superconducting coil framework cannot be damaged in the process of replacing the fixed joint 2 with the copper electrode 3 during heat treatment.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

The above-described embodiments merely represent embodiments of the invention, the scope of the invention is not limited to the above-described embodiments, and it is obvious to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention.

Claims

1. A Bi-2212 superconducting coil skeleton is characterized in that: the wire winding framework comprises a wire winding framework, a fixed joint and a copper electrode, wherein a wire inlet groove and a wire outlet groove are respectively formed in the two ends of the wire winding framework, and T-shaped grooves are formed in the two ends of the wire winding framework;

2. The Bi-2212 superconducting bobbin of claim 1, wherein: when a single-layer superconducting coil is wound, a spiral wire groove is further formed in the winding framework, and two ends of the spiral wire groove are respectively communicated with the wire inlet groove and the wire outlet groove.

3. The Bi-2212 superconducting bobbin of claim 1, wherein: the wire inlet groove and the wire outlet groove are symmetrically arranged with the T-shaped groove along the central line of the winding framework.

4. The Bi-2212 superconducting bobbin of claim 1, wherein: and the top of the copper electrode is provided with a chamfer.

5. The Bi-2212 superconducting bobbin of claim 1, wherein: threaded holes are further formed in the inner wall of the T-shaped groove.

6. The Bi-2212 superconducting bobbin of claim 5, wherein: the second T-shaped boss is provided with a through hole which is concentric with the threaded hole.

7. The Bi-2212 superconducting bobbin of claim 1, wherein: the fixed joint is made of non-copper materials.

8. The Bi-2212 superconducting bobbin of claim 7, wherein: the fixed joint is made of nickel-based alloy.