Impregnation method for high-temperature superconducting magnet, high-temperature superconducting magnet

Abstract

The present invention discloses an impregnation method for a high-temperature superconducting magnet and a high-temperature superconducting magnet. The impregnation method for a high-temperature superconducting magnet comprises the following steps: S1, heating the inner joint and the outer joint of the skeleton of the high-temperature superconducting magnet, and then impregnating the high-temperature superconducting tape and the skeleton at the inner joint and the outer joint with a first impregnation solder; heating other areas of the high-temperature superconducting magnet, that is, the areas of the high-temperature superconducting magnet other than the high-temperature superconducting tape and the skeleton at the inner joint and the outer joint, and then impregnating the other areas of the high-temperature superconducting magnet with a second impregnation solder. The first impregnation solder is a tin-lead alloy with low resistivity and a high melting point, and the second impregnation solder is a single indium with a low melting point, an indium-tin alloy, or a bismuth-tin alloy. The impregnation method for a high-temperature superconducting magnet can significantly reduce the impregnation temperature of the impregnation operation, expand the impregnation process window, and make the impregnation operation simpler.

Description

Technical Field

[0001] The invention belongs to the field of superconducting magnets, and in particular relates to an impregnation method for a high-temperature superconducting magnet and a high-temperature superconducting magnet. Background Art

[0002] The main feature of an uninsulated high-temperature superconducting magnet is that the electrical insulating material between turns is removed, and conductive material is filled between adjacent superconducting tapes and between the tapes and the skeleton to form a good electrical path between adjacent turns. Its most common structural form is a plurality of parallel flat pancake-shaped coils stacked on each other to form a whole, which are connected in series.

[0003] To reduce the inter-turn resistance of uninsulated superconducting magnets and prevent deformation of superconducting tapes under high current and strong magnetic fields, the production process of uninsulated superconducting magnets generally adopts a vacuum impregnation process, using a low-melting-point alloy with a melting point below 200°C as the impregnation solder. In addition, to reduce the joint resistance between adjacent coils, a low-resistivity solder is generally used. For example, a commonly used impregnation process using tin-lead alloy solder has the advantage of enabling integrated impregnation and very low resistivity. However, its disadvantage is that the melting point of tin-lead alloy is relatively high, reaching 183°C. To minimize the damage to the current-carrying capacity of the superconducting tape caused by high temperatures during the impregnation process, the operating temperature and impregnation time must be strictly controlled, which makes the operation difficult and the process window narrow. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides an impregnation method for a high-temperature superconducting magnet, comprising the following steps:

[0005] S1. Heating the inner joint and the outer joint of the skeleton of the high-temperature superconducting magnet, and then dipping the high-temperature superconducting tape and the skeleton at the inner joint and the outer joint with a first dipping solder;

[0006] S2. Heating other regions of the high-temperature superconducting magnet, that is, regions other than the high-temperature superconducting tape and the frame at the inner and outer joints, and then dipping the other regions of the high-temperature superconducting magnet with a second dipping solder.

[0007] Furthermore, in step S1 , the heating temperature is at least 5-10° C. higher than the melting point of the first dipping solder.

[0008] Furthermore, the first dipping solder is a tin-lead alloy with low resistivity and high melting point, and the heating temperature is 190-200°C.

[0009] Furthermore, in step S2, the heating temperature is at least 5-10°C higher than the melting point of the second dipping solder.

[0010] Furthermore, the second dipping solder is a low-melting-point indium element, and the heating temperature is 165-175°C.

[0011] Furthermore, the second dipping solder is an indium-tin alloy with a low melting point, and the heating temperature is 130-140°C.

[0012] Furthermore, the second dipping solder is a bismuth-tin alloy with a low melting point, and the heating temperature is 150-160°C.

[0013] Furthermore, before step S1, the following steps are also included:

[0014] S0, placing multiple strands of high-temperature superconducting tapes of a high-temperature superconducting magnet side by side in a metal skeleton slot to form a stack of high-temperature superconducting tapes;

[0015] S0', providing a metal protective layer on the stacked high-temperature superconducting tapes.

[0016] Furthermore, the metal protective layer is made of copper and has a thickness of 1-3 mm.

[0017] The present invention also provides a high-temperature superconducting magnet, which is produced by the above-mentioned impregnation method for high-temperature superconducting magnets.

[0018] Compared with the prior art, the impregnation method for a high-temperature superconducting magnet provided by the present invention has the following advantages: the first impregnation step can reduce the exposure time of the high-temperature superconducting magnet to high temperature and reduce the resistance at the joint; the second impregnation step can impregnate the entire high-temperature superconducting magnet into a whole. The above two-step impregnation process can greatly reduce the impregnation temperature of the impregnation operation, expand the impregnation process window, and simplify the impregnation operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A flow chart showing a method for impregnating a high-temperature superconducting magnet according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0020] The following is a detailed description of specific embodiments of the present invention. It should be understood that the embodiments of the present invention are not limited to the embodiments shown in the accompanying drawings, and the scope of protection of the present invention is not limited by the specific embodiments. The terms "first," "second," and similar terms used in the present invention do not indicate any order, quantity, or importance, but are only used to distinguish different components. Similarly, terms such as "one," "an," or "the" do not indicate a quantitative limitation, but rather indicate the presence of at least one. Unless otherwise expressly indicated, throughout the specification and claims, the term "comprise" or variations such as "include" or "comprising" will be understood to include the elements or components stated, without excluding other elements or components. Terms such as "connected" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0021] Unless otherwise defined, the meanings of all technical terms and scientific terms used in the present invention are the same as those commonly understood by ordinary technicians in the field. In addition, the meanings of the technical terms and scientific terms used in the present invention should be interpreted as having the same meanings as the corresponding terms defined in commonly used technical manuals, and should not be interpreted as having idealized or excessive formal meanings, unless explicitly defined in this way in the present invention.

[0022] Figure 1 A flow chart showing a method for impregnating a high-temperature superconducting magnet according to an embodiment of the present invention is shown. Figure 1 The impregnation method of the high-temperature superconducting magnet comprises the following steps:

[0023] S1. Heating the inner joint and the outer joint of the skeleton of the high-temperature superconducting magnet, and then dipping the high-temperature superconducting tape and the skeleton at the inner joint and the outer joint with a first dipping solder.

[0024] Specifically, the first dipping solder is a tin-lead alloy with low resistivity and high melting point.

[0025] Specifically, the heating temperature is at least 5-10° C. higher than the melting point of the first dipping solder.

[0026] Furthermore, in step S1, the melting point of the low-resistivity, high-melting-point tin-lead alloy material is 183°C. The inventors have verified through actual operation that when heating, the heating temperature is 190-200°C, which can ensure that the first dipping solder is fully melted, especially for large-sized high-temperature superconducting magnets, and can also save energy (no need for too high a temperature).

[0027] S2. Heating other regions of the high-temperature superconducting magnet, that is, regions other than the high-temperature superconducting tape and the frame at the inner joint and the outer joint, and then impregnating the other regions of the high-temperature superconducting magnet with a second impregnation solder.

[0028] Specifically, the second dipping solder is a low-melting-point indium single substance, a low-melting-point indium-tin alloy, or a low-melting-point bismuth-tin alloy.

[0029] Specifically, the heating temperature is at least 5-10° C. higher than the melting point of the second dipping solder.

[0030] In step S2, when the second dipping solder is low-melting-point elemental indium (melting point 156.6°C), the heating temperature is 165-175°C; when the second dipping solder is a low-melting-point indium-tin alloy (melting point 118°C), the heating temperature is 130-140°C; and when the second dipping solder is a low-melting-point bismuth-tin alloy (melting point 138°C), the heating temperature is 150-160°C. The inventors have verified through practical experiments that heating at these temperatures ensures that the second dipping solder is fully melted.

[0031] Furthermore, the impregnation method for the high-temperature superconducting magnet further comprises the following steps before step S1:

[0032] S0, placing multiple strands of high-temperature superconducting tapes of a high-temperature superconducting magnet side by side in a metal skeleton slot to form a stack of high-temperature superconducting tapes;

[0033] S0', providing a metal protective layer on the stacked high-temperature superconducting tapes.

[0034] Furthermore, the metal protective layer is made of copper and has a thickness of 1-3 mm.

[0035] The present invention also provides a high-temperature superconducting magnet, which is produced by the above-mentioned impregnation method for the high-temperature superconducting magnet.

[0036] In summary, the impregnation method of the high-temperature superconducting magnet provided by the present invention uses conductive solders with different melting points at different positions of the high-temperature superconducting magnet for two-step impregnation. Specifically, the first step of impregnation is performed at the joint positions inside and outside the skeleton using a low-resistivity, high-melting-point tin-lead alloy. Since the length of the joint accounts for a small proportion of the entire length of the uninsulated high-temperature superconducting magnet coil, the first step of impregnation can reduce the exposure time of the uninsulated high-temperature superconducting magnet to high temperature and reduce the resistance at the joint; then, a second step of impregnation is performed using a low-melting-point indium element, an indium-tin alloy, or a bismuth-tin alloy as a second impregnation solder to fill it into the interior of the high-temperature superconducting magnet, thereby impregnating the entire high-temperature superconducting magnet into a whole. The above-mentioned two-step impregnation process can greatly reduce the impregnation temperature of the impregnation operation, expand the impregnation process window, and simplify the impregnation operation.

[0037] The foregoing descriptions of specific exemplary embodiments of the present invention are for purposes of illustration and description. These descriptions are not intended to limit the invention to the precise forms disclosed, and it is apparent that many modifications and variations are possible in light of the foregoing teachings. The exemplary embodiments have been selected and described for the purpose of explaining the specific principles of the invention and their practical application, thereby enabling those skilled in the art to realize and utilize a variety of exemplary embodiments of the invention and various options and variations. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. A method for impregnating a high-temperature superconducting magnet, characterized in that: The following steps are involved: S1. Heating the inner joint and the outer joint of the skeleton of the high-temperature superconducting magnet, and then dipping the high-temperature superconducting tape and the skeleton at the inner joint and the outer joint with a first dipping solder; S2. Heating other regions of the high-temperature superconducting magnet, i.e., regions other than the high-temperature superconducting tape and the frame at the inner and outer joints, and then impregnating the other regions of the high-temperature superconducting magnet with a second impregnation solder; In step S1, the heating temperature is 5-10° C. higher than the melting point of the first dipping solder; The first dipping solder is a tin-lead alloy with low resistivity and high melting point, and the heating temperature is 190-200°C; In step S2, the heating temperature is 5-10°C higher than the melting point of the second dipping solder. The second dipping solder is a low melting point indium element, and the heating temperature is 165-175°C. or, The second dipping solder is a low melting point indium tin alloy, and the heating temperature is 130-140°C. or, The second dipping solder is a bismuth-tin alloy with a low melting point, and the heating temperature is 150-160°C.

2. The impregnation method for a high-temperature superconducting magnet according to claim 1, characterized in that: Before step S1, the method further includes the following steps: S0, placing multiple strands of high-temperature superconducting tapes of the high-temperature superconducting magnet side by side in the metal skeleton slot to form a stack of high-temperature superconducting tapes; S0', providing a metal protective layer on the stacked high-temperature superconducting tapes.

3. The impregnation method for a high-temperature superconducting magnet according to claim 2, characterized in that: The metal protective layer is made of copper and has a thickness of 1~3mm.

4. A high-temperature superconducting magnet, characterized in that: The high-temperature superconducting magnet is produced by the impregnation method according to any one of claims 1 to 3.

Images