Compound Superconducting Twisted Wire With Cr Barrier Against Strand Fusion
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Solution Overview
Problem
Conventional compound superconducting twisted wires produced by the react-and-wind process lack sufficient strength against tension and have a low cross-section compression ratio, leading to adhesion between strands during heat treatment, which hinders uniform bending strain application and can result in strand damage.
Innovation Solution
A compound superconducting twisted wire configuration with a core-like superconductor part, a cylindrical reinforcing part, and a stabilizing part, including a Cr plate layer with a thickness of 0.5 um or less to prevent thermal fusion, enhancing non-adhesiveness and tension strength by optimizing the volume ratios of these components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the cross section compression ratio is increased to enhance the electric current density, then the electric current density is improved, but the strands are likely to partially adhere to each other due to thermal fusion during heat treatment
Solution Approach 1:
A Cr plate layer with thickness of 0.5 µm or less is introduced as an intermediary barrier between adjacent compound superconducting strands. This Cr layer prevents thermal fusion and adhesion between strands during heat treatment while allowing the cross section compression ratio to be increased to enhance electric current density. The Cr plate acts as a physical separator that maintains strand independence even under compression.
Solution Approach 2:
The thickness of the Cr plate layer is controlled to be 0.5 µm or less, optimizing the balance between preventing strand adhesion and minimizing space occupation. This parameter control allows sufficient compression ratio for high current density while maintaining strand separation. The specific thickness parameter resolves the contradiction by providing just enough barrier function without excessive volume.
2Reliability
If a Cr plate layer with thickness of 0.5 um or less is introduced to prevent thermal fusion, then the non-adhesiveness between strands is improved, but the device complexity increases
Solution Approach 1:
The Cr plate layer is applied locally only at the surfaces of compound superconducting strands where adhesion prevention is needed, rather than throughout the entire wire structure. This localized application provides the necessary non-adhesiveness function while minimizing the overall complexity increase. The Cr coating is confined to specific locations (strand surfaces) rather than being a universal structural modification.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution significantly improves the non-adhesiveness and separation of strands, while achieving a tension strength comparable to or exceeding conventional wires, enabling the commercial production of superconducting coils with enhanced bending properties.
Implementation Method 1
a Cr plate layer with a thickness of 0.5 um or less on a surface of the compound superconducting strand for preventing thermal fusion between the compound superconducting strands
Implementation Method 2
a core-like compound superconductor part (11), a cylindrical reinforcing part (12), and a cylindrical stabilizing part (13)... the core-like compound superconductor part (11) includes a plurality of compound superconducting filaments (15) each including a compound superconducting phase
Data Source
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AI summary
The present invention provides: a compound superconducting twisted wire in which non-adhesiveness between compound superconducting strands or separation easiness after adhesion is improved while a strength against tension is improved to a degree to be equivalent to or stronger than that of a conventional compound superconducting twisted wire; and a rewinding method thereof. The compound superconducting twisted wire 1 of the present invention includes a plurality of compound superconducting strands 10 being twisted to form a twisted structure, in which each of the compound superconducting strands 10 includes a compound superconductor part 11, a reinforcing part 12 and a stabilizing part 13, in which the compound superconductor part 11 includes a plurality of compound superconducting filaments 15 and a first matrix 16, the compound superconducting filaments 15 each including a compound superconducting phase, in which the reinforcing part 12 is disposed on an outer circumferential side of the compound superconductor part, and comprises a plurality of reinforcing filaments 18 and a second matrix 19, in which the stabilizing part 13 is disposed on at least one side of an inner circumferential side and an outer circumferential side of the reinforcing part. In the compound superconducting twisted wire, a volume ratio of the reinforcing part relative to the compound superconducting strand is larger than a volume ratio of the compound superconductor part relative to the compound superconducting strand, or a metal layer 20 with a thickness of 2 µm or less is formed on a surface of the compound superconducting strand for preventing thermal fusion between the compound superconducting strands.