Superconducting Wire Adhesion Control for Thermal Stress
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Solution Overview
Problem
Conventional superconducting wires and coils face deterioration due to thermal stress from differences in thermal expansion coefficients, leading to complex manufacturing processes and potential breakage of the superconducting layer.
Innovation Solution
A superconducting wire with a substrate, superconducting layer, stabilization layers, and protective layers, where the adhesion strength between the stabilization and protective layers is lower than the superconducting layer, allowing them to detach before the superconducting layer is broken, and a coil with an insulator having a higher thermal expansion coefficient than the wire, reducing thermal stress impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the adhesion strength between stabilization layers and protective layers is made lower than the superconducting layer strength, then the superconducting layer is protected from thermal stress breakage, but the structural integrity and mechanical strength of the wire is reduced
Solution Approach 1:
The patent introduces a release coating layer as an intermediary between the protective coating layer and the superconducting layer. This intermediate layer has controlled adhesion strength that allows it to detach preferentially under thermal stress, protecting the superconducting layer while maintaining overall structural integrity during normal operation
Solution Approach 2:
The patent modifies the adhesion strength parameter of the coating layers by controlling the thickness and material composition of the release coating layer. By adjusting these parameters, the release layer's adhesion is reduced below that of the protective layer, enabling selective detachment behavior under thermal stress
2Ease of manufacture
If conventional insulation coating oxide superconducting wire is used with thermosetting resin impregnation, then the coil structure is formed, but thermal stress causes the resin and releasing material layer to detach, complicating the manufacturing process
Solution Approach 1:
The patent converts the harmful effect of thermal stress-induced detachment into a beneficial protective mechanism. The release coating layer is designed to detach under thermal stress, but this detachment occurs in a controlled manner that protects the superconducting layer rather than causing damage, thus converting the harmful thermal expansion mismatch into a protective feature
Solution Approach 2:
The release coating layer is pre-applied to the superconducting layer before the protective coating layer and impregnation process. This preliminary action ensures that when thermal stress occurs during coil operation, the detachment has already been predetermined and controlled, avoiding the need for post-manufacturing adjustments or repairs
3Reliability
If the carbon layer breaking strength is made lower than the superconducting layer, then thermal stress is absorbed by the carbon layer fracture, but the wire structure becomes more fragile and prone to damage
Solution Approach 1:
The release coating layer serves as an intermediary that absorbs and redistributes thermal stress through controlled detachment, preventing stress concentration that would otherwise require sacrificing structural components like the carbon layer. This intermediary mechanism protects both the superconducting layer and maintains overall structural integrity
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 configuration prevents superconducting property deterioration from thermal stress without complicating the manufacturing process, ensuring the superconducting layer remains intact by allowing the stabilization and protective layers to detach before excessive stress is applied.
Implementation Method 1
thermal stress resulting from a difference between the thermal expansion coefficient of the impregnating material and the thermal expansion coefficient of the superconducting wire
Implementation Method 2
a superconducting layer disposed on the substrate
Data Source
AI summary
A superconducting coil according to the present disclosure includes: a substrate having a first surface and a second surface; a superconducting layer having a third surface and a fourth surface; respective stabilization layers; and respective protective layers. The second surface is opposite to the first surface. The fourth surface is opposite to the third surface. The superconducting layer is disposed on the substrate such that the third surface faces the second surface. The respective stabilization layers are disposed on the first surface and the fourth surface. The respective protective layers are disposed on the stabilization layers. Adhesion strength between each of the stabilization layers and each of the protective layers is lower than strength of the superconducting layer.