Nb3Sn Superconductor Wire Precursor with Segmented Filaments
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Solution Overview
Problem
Nb3Sn superconductor wires manufactured by the internal diffusion method face challenges with increased AC loss and magnetic instability due to magnetic coupling between filaments, limiting their critical current performance and magnetic stability.
Innovation Solution
A precursor for Nb3Sn superconductor wires is designed with a plurality of Nb-based single core wires and Sn-based single core wires, each coated with a Cu-based matrix, and a cylindrical diffusion barrier, featuring varying Cu/Nb ratios and arrangements to optimize filament spacing and distribution, reducing magnetic coupling and enhancing critical current density and AC loss characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the internal diffusion method is used to manufacture Nb3Sn superconductor wire with high critical current density, then a large quantity of Sn can be provided and the thickness of the generated Nb3Sn can be increased, but the spacing between Nb-based cores is reduced and AC loss increases due to magnetic coupling between adjacent filaments
Solution Approach 1:
The patent divides the superconductor wire into multiple independent filaments (Nb-based cores) separated by Cu-based matrix regions. This segmentation reduces the magnetic coupling between adjacent filaments, thereby reducing AC loss while maintaining high critical current density through adequate Sn quantity in each filament.
Solution Approach 2:
The patent creates local variations in the Cu-based matrix composition and structure surrounding each Nb-based core. By optimizing the local Cu-Sn alloy composition and matrix density around each filament, the patent achieves adequate spacing to reduce magnetic coupling while maintaining efficient Sn diffusion to generate sufficient Nb3Sn thickness for high critical current density.
2Quantity of substance
If the spacing between Nb-based cores is reduced to increase the number of filaments, then critical current density can be increased, but magnetic coupling between filaments increases and magnetic stability deteriorates
Solution Approach 1:
The patent segments the superconductor wire into multiple isolated filaments embedded in a Cu-based matrix. This segmentation provides electrical and magnetic isolation between filaments, reducing magnetic coupling and improving magnetic stability while maintaining high filament density for increased critical current density.
Solution Approach 2:
The Cu-based matrix acts as an intermediary material between adjacent Nb-based cores. This matrix provides physical separation and magnetic shielding, reducing the direct magnetic coupling between filaments while allowing controlled Sn diffusion to form Nb3Sn superconductor phases around each core.
3Manufacturing precision
If uniform disposition of Nb and Sn elements is achieved, then critical current performance can be optimized, but manufacturing complexity increases
Solution Approach 1:
The patent employs a preliminary structured precursor configuration where Nb-based cores and Cu-based matrix regions are arranged in a predetermined pattern before heat treatment. This preliminary action ensures uniform element distribution and adequate spacing are achieved through the initial structure design, simplifying the subsequent diffusion process and reducing manufacturing complexity.
Solution Approach 2:
The patent optimizes key parameters of the precursor structure, including the size, shape, and spacing of Nb-based cores and Cu-based matrix regions. By carefully controlling these geometric parameters and the Cu/Sn composition ratios, the patent achieves uniform element distribution and optimal magnetic coupling reduction without excessive manufacturing complexity.
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 approach results in Nb3Sn superconductor wires with improved critical current characteristics, reduced AC loss, and enhanced magnetic stability, enabling stable energization and efficient operation in superconducting magnet systems.
Implementation Method 1
reacting Sn of the Sn-based core with Nb via the Cu-based matrix by heat treatment, thereby generating Nb3Sn
Implementation Method 2
a cylindrical diffusion barrier comprising Ta or Nb
Data Source
AI summary
A precursor for a Nb3Sn superconductor wire to be manufactured by the internal diffusion method. The precursor includes Nb-based single core wires, Sn-based single core wires, and a cylindrical diffusion barrier made of Ta or Nb. Each Nb-based single core wire includes a Nb-based core coated with a Cu-based coating made of a Cu-based matrix. Each Sn-based single core wire includes a Sn-based core coated with a Cu-based coating made of a Cu-based matrix. The Nb-based single core wires and the Sn-based single core wires are regularly disposed in the diffusion barrier. The Nb-based single core wires includes at least two kinds of Nb-based single core wires having different Cu/Nb ratios and the Cu/Nb ratio is a cross sectional area ratio of the Cu-based coating to the Nb-based core.