Superconducting Wire Surface Roughness for Resin Adhesion
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Solution Overview
Problem
Superconducting wires experience peeling of the insulating resin layer due to inadequate surface texture of the substrate, leading to instability and reduced performance.
Innovation Solution
The superconducting wire design includes a substrate with a second surface having an arithmetic average roughness greater than 0.02 µm and a maximum height roughness less than 5 µm, along with a stabilization layer having specific roughness parameters, to enhance the anchoring effect and prevent peeling of the insulating resin layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the substrate surface is polished to achieve smooth surface (low roughness), then the manufacturing precision is improved, but the insulating resin layer peeling occurs due to insufficient anchoring effect
Solution Approach 1:
The invention changes the surface roughness parameters from conventional smooth values (Ra < 0.03 μm) to a controlled rough range (0.03 μm ≤ Ra ≤ 0.5 μm, with Rz ≤ 5 μm). This parameter modification creates surface irregularities that provide mechanical anchoring for the insulating resin layer, resolving the contradiction between smoothness and adhesion.
Solution Approach 2:
The invention introduces surface curvature variations through controlled roughness, creating microscopic peaks and valleys on the substrate surface. These curved surface features enhance the anchoring effect by providing mechanical interlocking sites for the insulating resin layer, preventing peeling while maintaining manufacturing precision.
2Reliability
If the substrate surface roughness is increased to prevent resin layer peeling, then the adhesion is improved, but the manufacturing precision deteriorates
Solution Approach 1:
The invention defines specific parameter ranges for surface roughness (Ra: 0.03-0.5 μm, Rz: ≤5 μm) that balance adhesion and manufacturing precision. These controlled parameters ensure sufficient anchoring effect while maintaining manufacturability, resolving the contradiction between roughness for adhesion and precision for manufacturing.
Solution Approach 2:
The invention applies localized surface roughness control, where the arithmetic average roughness (Ra) and maximum height roughness (Rz) are independently optimized. This allows different aspects of roughness to serve different functions: Ra provides overall anchoring while Rz limits excessive irregularities, maintaining manufacturing precision.
3Ease of manufacture
If conventional polishing is used to achieve smooth substrate surface, then the manufacturing process is simple, but the critical current performance deteriorates due to resin layer peeling
Solution Approach 1:
The invention modifies the target surface roughness parameters from conventional smooth values to a controlled rough range, which can be achieved through standard polishing processes with adjusted parameters. This maintains manufacturing simplicity while preventing resin layer peeling and preserving critical current performance.
Solution Approach 2:
The invention applies surface roughness control as a preventive measure before resin layer application. By pre-establishing the anchoring effect through controlled roughness, the design prevents future peeling issues that would compromise critical current performance, cushioning against potential failures.
Data Source
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AI summary
A superconducting wire (100) comprises a substrate (1) and a superconducting layer (3). The substrate (1) has a first surface (11) and a second surface (12). The second surface (12) is opposite to the first surface. The superconducting layer (3) faces the first surface. The second surface (12) has an arithmetic average roughness (Ra) larger than 0.02 µm. The second surface (12) has a maximum height roughness (Rz) smaller than 5 µm.