Preparation method of MgB2 multi-core superconducting wire hysteresis loop test sample
By using concentrated nitric acid to corrode the outsourcing sleeve of MgB2 multi-core superconducting wire and monitoring the corrosion degree, the problem of easy damage to the core wire by mechanical delamination method is solved, and the effect of efficient preparation of test samples and obtaining complete hysteresis loop data is achieved.
Patent Information
- Application Number
- CN202510242505.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-03
- Publication Date
- 2025-05-02
AI Technical Summary
In the prior art, when testing the magnetic characteristic signals of MgB2 multi-core superconducting wires, the signal disorder is easily caused by strong magnetic interference of the Monel tube, and the mechanical delamination method is prone to damage the superconducting core wire.
Concentrated nitric acid is used to corrode the outsourcing sleeve of MgB2 multi-core superconducting wire, and the corrosion degree of the outsourcing sleeve is monitored during the corrosion process to ensure that the core wire is not damaged, and an undamaged core wire is obtained as a test sample.
The success rate of test sample preparation was improved, the outsourcing sleeve interference was eliminated, and complete hysteresis loop data was obtained, providing a basis for calculating flux pinning and critical current density.
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Figure CN119915579A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of superconducting wire testing, and in particular relates to a MgB 2 A method for preparing a hysteresis loop test sample of a multi-core superconducting wire. Background Art
[0002] The hysteresis loop is the intuitive evidence of the antimagnetic properties of superconducting materials. The hysteresis loop test is a method to obtain the main data for analyzing the magnetic flux pinning performance. For superconductor bulk materials, the critical current density J can be calculated based on the hysteresis loop test. c For MgB 2 For multi-core superconducting wires, researchers need to test their hysteresis loop data to calculate the pinning performance of the wires and improve the wire preparation process by evaluating and improving the pinning performance.
[0003] In order to increase MgB 2 Processability of multi-core superconducting wire, MgB 2 The outer sheath of multi-core superconducting wire is usually made of Monel tube. The material of Monel tube is Ni-Cu alloy, which has strong magnetism. Superconducting material has strong antimagnetism. Therefore, it is not necessary to directly test MgB 2 The magnetic characteristic signal of multi-core superconducting wire will be strongly interfered by the Monel tube. 2 The magnetic characteristic signals of multi-core superconducting wires are usually separated from the Monel tube by mechanical delamination. However, due to the high hardness of the Monel tube, mechanical delamination can easily damage the superconducting core wire. Therefore, a test sample preparation method that can reduce the probability of core wire damage is urgently needed. Summary of the invention
[0004] The purpose of the present invention is to overcome the above-mentioned deficiencies in the prior art and provide a MgB 2 A method for preparing a multi-core superconducting wire hysteresis loop test sample. The preparation method comprises using concentrated nitric acid to treat MgB 2 The multi-core superconducting wire is corroded, and the corrosion degree of the outer sheath is monitored during the corrosion process to obtain undamaged core wires as test samples, thus solving the problem that mechanical delamination may easily lead to core wire damage.
[0005] To achieve the above purpose, the technical solution adopted by the present invention is: a MgB 2 A method for preparing a multi-core superconducting wire hysteresis loop test sample, characterized in that the preparation method comprises the following steps: using concentrated nitric acid to treat MgB 2 The outer sheath of the multi-core superconducting wire is corroded, and the corrosion degree of the outer sheath is monitored during the corrosion process to obtain a test sample.
[0006] The above-mentioned MgB2 A method for preparing a multi-core superconducting wire hysteresis loop test sample, characterized in that the MgB 2 The multi-core superconducting wire is formed into a U-shape or an I-shape before corrosion.
[0007] The present invention comprises the following steps: 2 The multi-core superconducting wire is made into a U-shape or an X-shape, which is convenient for insertion and removal during the process of monitoring the corrosion degree.
[0008] The above-mentioned MgB 2 The method for preparing a multi-core superconducting wire hysteresis loop test sample is characterized in that the mass concentration of the concentrated nitric acid is not less than 68%.
[0009] The above-mentioned MgB 2 The method for preparing a multi-core superconducting wire hysteresis loop test sample is characterized in that the monitoring method is: MgB is taken out from concentrated nitric acid every corrosion time not exceeding 10s. 2 The multi-core superconducting wire was rinsed with deionized water and ethanol in turn and then dried. Then, a magnet was used to surround the MgB 2 The outer surface of the corroded portion of the multi-core superconducting wire stops corroding when there is no attractive force during the winding process.
[0010] The present invention monitors the corrosion process and controls the corrosion time to avoid MgB 2 Excessive corrosion of multi-core superconducting wires leads to MgB 2 The core wires inside the multi-core superconducting wire are separated or scattered, affecting the subsequent magnetic signal test; when the magnet is weakly attracted, the time interval for subsequent monitoring is shortened; by corroding MgB 2 The multi-core superconducting wire is rinsed with deionized water and ethanol in turn and then dried, which can remove the nitric acid solution remaining on the surface and avoid adverse effects on corrosion monitoring and subsequent magnetic signal testing of the test samples.
[0011] The above-mentioned MgB 2 A method for preparing a multi-core superconducting wire hysteresis loop test sample, characterized in that the magnet is close to MgB 2 The maximum dimension of one end of the multi-core superconducting wire is not greater than 0.6 cm.
[0012] The present invention controls the magnet to be close to MgB 2 The length of one end of the multi-core superconducting wire is used to prevent the magnet from being too large, so that MgB 2 The outer sheath of the non-corroded part of the multi-core superconducting wire attracts the magnet, resulting in inaccurate judgment of the corrosion degree, which in turn makes MgB 2 Excessive corrosion of multi-core superconducting wire.
[0013] The above-mentioned MgB 2 A method for preparing a multi-core superconducting wire hysteresis loop test sample, characterized in that the standard of the test sample is: MgB 2 The outer sheath of the corroded part of the multi-core superconducting wire is completely detached, and MgB 2 The core wires inside the multi-core superconducting wire did not show any signs of spreading or separating.
[0014] The present invention limits the standard of the test sample to avoid the outer sheath not being completely detached when the corrosion is incomplete, so that the magnetic signal of the outer sheath seriously affects the subsequent magnetic signal test; avoid the phenomenon that the core wire is scattered or separated when the corrosion is excessive, and the subsequent measured magnetic signal cannot reflect the MgB 2 The real magnetic signature of a multi-core superconducting wire.
[0015] Compared with the prior art, the present invention has the following advantages:
[0016] 1. The present invention uses concentrated nitric acid to treat MgB 2 The multi-core superconducting wire is corroded, and the corrosion degree of the outer sheath is monitored during the corrosion process to obtain undamaged core wires as test samples. Compared with the mechanical delamination method used in the prior art to prepare test samples, the method of the present invention can improve the success rate of preparing test samples.
[0017] 2. The test sample prepared by the present invention can eliminate the interference of the outer sheath and meet the conditions for testing the magnetic signal. After the magnetic signal test, a complete hysteresis loop can be obtained, providing a basis for calculating the magnetic flux pinning and the critical current density.
[0018] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 This is a physical picture of the test sample obtained in Example 1 of the present invention.
[0020] Figure 2 This is the hysteresis loop diagram of the test sample obtained in Example 1 of the present invention.
[0021] Figure 3 This is a physical picture of the test sample obtained in Comparative Example 1 of the present invention.
[0022] Figure 4 MgB is not corroded 2 Hysteresis loop diagram of multi-core superconducting wire.
[0023] Figure 5 This is the hysteresis loop diagram of the test sample obtained in Comparative Example 2 of the present invention. DETAILED DESCRIPTION
[0024] Example 1
[0025] The preparation method of this embodiment comprises the following steps:
[0026] Cut 10cm of MgB with Monel tube as outer sheath 2 The multi-core superconducting wire is made into a "F" shape, and then MgB 2 The two ends of the multi-core superconducting wire were fixed on the top of a container filled with 68% concentrated nitric acid, so that MgB 2 The middle part of the multi-core superconducting wire is immersed in concentrated nitric acid to corrode the outer sheath. During the corrosion process, the corrosion degree of the outer sheath is monitored: MgB is taken out from the concentrated nitric acid every 10 seconds. 2 The multi-core superconducting wire was rinsed with deionized water and ethanol in turn and then dried. Then, a magnet was used to surround the MgB 2 The outer surface of the corroded part of the multi-core superconducting wire is stopped from being corroded when there is no attraction during the winding process to obtain a test sample; the magnet is a cylinder, close to MgB 2 The diameter of one end face of the multi-core superconducting wire is 0.5 cm.
[0027] The test sample obtained in this embodiment has an appearance as follows Figure 1 As shown, the outer sheath of the test sample is completely detached, and MgB 2 There is no phenomenon of core wires inside the multi-core superconducting wire spreading or separating.
[0028] The test sample obtained in this embodiment is tested for magnetic signal in a physical property measurement system (PPMS), and the hysteresis loop is as follows: Figure 2 As shown, MgB 2 Complete hysteresis loop of multi-core superconducting wire.
[0029] Comparative Example 1
[0030] The difference between this comparative example and Example 1 is that the corrosion process is not monitored and the corrosion time is 220s.
[0031] The appearance of the test sample obtained in this comparative example is as follows Figure 3 As shown, the outer sheath of the test sample is completely detached, but MgB 2 The core wires inside the multi-core superconducting wire begin to spread out.
[0032] Comparative Example 2
[0033] The difference between this comparative example and Example 1 is that the corrosion process is not monitored and the corrosion time is 10 s.
[0034] The corrosion time of this comparative example is short, and the outer sheath is not completely separated; the MgB 2The multi-core superconducting wire and the test sample are tested for magnetic signals in the physical property measurement system (PPMS), and the hysteresis loop is as follows: Figure 4 and Figure 5 As shown, compared with the uncorroded MgB 2 Multi-core superconducting wire, from Figure 5 It can be seen that the magnetic signal measured after the outer sheath is corroded is weakened. 2 The magnetic signal interference of the multi-core superconducting wire is reduced, but due to the presence of a partial outer sheath on the surface of the test sample, a complete hysteresis loop is not obtained.
[0035] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural transformation made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.
Claims
1. A method for preparing a MgB2 multi-core superconducting wire hysteresis loop test sample, characterized in that: The preparation method comprises the following steps: using concentrated nitric acid to corrode the outer sheath of the MgB2 multi-core superconducting wire, and monitoring the corrosion degree of the outer sheath during the corrosion process to obtain a test sample.
2. The method for preparing a MgB2 multi-core superconducting wire hysteresis loop test sample according to claim 1, characterized in that: The MgB2 multi-core superconducting wire is formed into a U shape or an I-shape before corrosion.
3. The method for preparing a MgB2 multi-core superconducting wire hysteresis loop test sample according to claim 1, characterized in that: The mass concentration of the concentrated nitric acid is not less than 68%.
4. The method for preparing a MgB2 multi-core superconducting wire hysteresis loop test sample according to claim 1, characterized in that: The monitoring method is as follows: the MgB2 multi-core superconducting wire is taken out from concentrated nitric acid every corrosion time of no more than 10 seconds, the surface is rinsed with deionized water and ethanol in turn and then dried, and then a magnet is used to surround the outer surface of the corroded part of the MgB2 multi-core superconducting wire, and the corrosion is stopped when there is no attraction during the surrounding process.
5. The method for preparing a MgB2 multi-core superconducting wire hysteresis loop test sample according to claim 4, characterized in that: The maximum dimension of the magnet close to one end of the MgB2 multi-core superconducting wire is no more than 0.6 cm.
6. The method for preparing a MgB2 multi-core superconducting wire hysteresis loop test sample according to claim 1, characterized in that: The standard of the test sample is that the outer sheath of the corroded part of the MgB2 multi-core superconducting wire is completely detached, and the core wire does not appear to be scattered or separated.