Superconducting Wire Edge Thickness for Peeling Prevention
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Solution Overview
Problem
Superconducting wires with a ceramic layer on a metal substrate face stress due to thermal expansion differences, leading to local peeling and degradation of superconducting properties.
Innovation Solution
A superconducting wire design where the superconducting material layer covers the side surfaces and part of the second main surface of the substrate, with varying thickness to enhance bonding strength and prioritize protection of the primary current path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ceramic layer is formed on a metal substrate in a superconducting wire, then the superconducting properties are improved, but thermal expansion stress causes local peeling at the edges of the ceramic layer
Solution Approach 1:
The patent applies local quality by making the superconducting material layer thickness non-uniform, specifically making it thicker at the edges and thinner at the center. This local variation in thickness compensates for the thermal expansion stress concentration at the edges, preventing peeling while maintaining superconducting properties.
Solution Approach 2:
The patent changes the thickness parameter of the superconducting material layer from uniform to non-uniform distribution. By adjusting the thickness parameter locally (thicker at edges, thinner at center), the stress distribution is optimized to prevent interface peeling while preserving superconducting functionality.
2Strength
If the superconducting material layer thickness is increased to prevent peeling, then bonding strength is improved, but the wire becomes more complex and harder to manufacture
Solution Approach 1:
Instead of uniformly increasing the layer thickness which would complicate manufacturing, the patent applies local quality by selectively increasing thickness only at the edges where peeling occurs. This targeted approach improves bonding strength where needed without adding overall structural 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
This design suppresses local peeling and maintains stable superconducting properties by increasing bonding strength and prioritizing protection of the critical superconducting material layer.
Implementation Method 1
an oxide superconducting wire is of interest. The oxide superconducting wire includes a superconducting material layer made of an oxide superconductor which is a high-temperature superconductor having a transition temperature equal to or higher than the liquid nitrogen temperature
Implementation Method 2
When such a superconducting wire is cooled to its critical temperature, a difference in thermal expansion coefficient between the metal substrate and the ceramic layer causes a stress to be applied from the metal substrate to the ceramic layer in the multilayer structure
Data Source
AI summary
A superconducting wire includes a substrate and a superconducting material layer. The substrate includes a first main surface and a second main surface opposite to the first main surface. The superconducting material layer is disposed on the first main surface. Along at least a part of the superconducting wire in a direction in which the superconducting wire extends, the superconducting material layer is disposed to cover a side surface of the substrate in a width direction of the substrate and cover at least a part of the second main surface. A thickness of the superconducting material layer located on the first main surface varies along the width direction. A maximum thickness of the superconducting material layer located on the second main surface is smaller than a maximum thickness of the superconducting material layer located on the first main surface.