Graded Nickel Alloy Substrate for Superconducting Wire

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Solution Overview

Problem

Superconducting wires produced using ferromagnetic substrates, such as Ni, experience high saturation magnetization and increased AC loss due to hysteresis loss when current is conducted, which is not effectively addressed by existing methods.

Innovation Solution

A substrate and superconducting wire structure comprising a copper layer, an alloy layer with varying nickel concentration, a nickel layer, and an intermediate layer, where the nickel concentration in the alloy layer is higher at the interface with the nickel layer than with the copper layer, and the nickel layer is alloyed under reduced pressure without hydrogen to reduce magnetism and prevent oxide layer formation, facilitating epitaxial growth and orientation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a ferromagnetic substrate such as Ni is used for the oriented metal substrate, then the crystal orientation of the superconducting layer can be arranged in three dimensions, but the saturation magnetization of the substrate is great and the AC loss caused by hysteresis loss is increased

Engineering Contradiction:
Improvecrystal orientationVSAvoidAC loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The nickel layer is divided into multiple layers with different nickel concentrations. The first nickel layer has a nickel concentration of 5-30 at%, the second nickel layer has a nickel concentration of 70-95 at%, and the third nickel layer has a nickel concentration of 30-70 at%. This segmentation allows different regions to serve different functions: the first layer reduces AC loss by lowering saturation magnetization, while the second and third layers maintain crystal orientation through epitaxial growth

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the nickel layer are given different nickel concentrations to perform different functions. The region adjacent to the oriented metal substrate (first nickel layer) has lower nickel concentration to reduce magnetization and AC loss, while the region adjacent to the intermediate layer (second nickel layer) has higher nickel concentration to maintain crystal orientation for epitaxial growth

Inventive Principle:
Principle #3Local quality

2Loss of energy

If the nickel concentration in the alloy layer is increased to reduce AC loss, then the saturation magnetization decreases, but the crystal orientation and epitaxial growth may be affected

Engineering Contradiction:
Improvehysteresis lossVSAvoidepitaxial growth
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The nickel layer is segmented into three layers with progressively increasing nickel concentrations from the substrate interface toward the intermediate layer interface. This allows the lower nickel concentration region to reduce hysteresis loss while the higher nickel concentration region maintains crystal orientation for epitaxial growth

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The nickel concentration is locally optimized in different regions: lower concentration (5-30 at%) near the substrate to reduce magnetization, and higher concentration (70-95 at%) near the intermediate layer to maintain crystal orientation and enable epitaxial growth

Inventive Principle:
Principle #3Local quality

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 proposed structure reduces AC loss by decreasing hysteresis loss and maintaining favorable crystal orientation, resulting in improved performance of the superconducting wire.

Implementation Method 1

an alloy layer containing copper and nickel, formed on the copper layer

Methodology Applied
Scientific EffectAlloying:

Implementation Method 2

the saturation magnetization of the substrate is great and the AC loss caused by hysteresis loss is increased

Methodology Applied
Scientific EffectHysteresis loss: Magnetic Hysteresis

Implementation Method 3

epitaxial growth of a thin film such as an intermediate layer and a superconducting layer while maintaining the biaxial orientation of the oriented metal substrate

Methodology Applied
Scientific EffectEpitaxial growth: Epitaxy

Data Source

PatentEP2453447B1Substrate, method of producing substrate superconducting wire and method of producing of superconducting wire
Publication Date: 2017.11.01 SUMITOMO ELECTRIC INDUSTRIES LTD
  • EP2453447B1 patent drawingFigure 1~2
  • EP2453447B1 patent drawingFigure 3(a)~3(e)
  • EP2453447B1 patent drawingFigure 4(a)~4(b)

AI summary

A substrate (1) of the present invention includes a copper layer (2), an alloy layer (3) containing copper and nickel, formed on the copper layer (2), a nickel layer (4) formed on the alloy layer (3), and an intermediate layer (5) formed on the nickel layer (4). The concentration of nickel in the alloy layer (3) at the interface between the alloy layer (3) and the nickel layer (4) is greater than the concentration of nickel in the alloy layer (3) at the interface between the alloy layer (3) and the copper layer (2). According to the present invention, there can be provided a substrate (1) that allows the AC loss of a superconducting wire (7) to be reduced, a method of producing a substrate (1), a superconducting wire (7), and a method of producing a superconducting wire (7).