Composite Superconductive Wire Using Lead-Free Sn-Bi Solder
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Solution Overview
Problem
Y-based superconductive wire-materials face issues with stabilizing layer erosion during soldering, leading to degraded superconductive properties and insufficient bonding strength, and the use of lead-based solders is environmentally undesirable.
Innovation Solution
A composite superconductive wire-material is formed by immersing a thin-film superconductive wire-material and electroconductive tape into a solder bath using a lead-free Sn-Bi solder alloy at temperatures between 160° C. and 200° C., with specific immersion time and temperature conditions to prevent stabilizing layer erosion and ensure strong bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional soldering is applied to bond electroconductive tape with thin-film superconductive wire-material, then bonding is achieved, but the stabilizing layer is eroded exposing the superconductive layer and degrading superconductive properties
Solution Approach 1:
The invention changes the chemical composition parameters of the solder alloy from conventional formulations to a specific Sn-Bi-based alloy with controlled composition ratios. This parameter change enables the solder to bond effectively while preventing erosion of the stabilizing layer, thus maintaining superconductive properties.
Solution Approach 2:
The invention applies different material properties to different parts of the bonding system: the Sn-Bi-based solder provides protective bonding characteristics at the interface, while the silver stabilizing layer maintains its protective function over the superconductive layer. This local differentiation of material qualities prevents erosion while ensuring bonding.
2Reliability
If soldering process is applied to bond electroconductive tape with thin-film superconductive wire-material, then bonding is achieved, but bonding strength is insufficient due to stabilizing layer erosion
Solution Approach 1:
The invention modifies the solder alloy composition parameters to create a Sn-Bi-based alloy that provides both adequate bonding strength and protection against stabilizing layer erosion. The specific composition parameters enable the solder to penetrate and bond effectively without being excessively aggressive to the silver layer.
3Ease of manufacture
If lead-based solder is used for bonding, then bonding process is conventional and straightforward, but environmental restrictions prohibit its use
Solution Approach 1:
The invention extracts and removes the harmful lead component from the solder alloy, replacing it with environmentally benign Sn-Bi-based composition. This extraction eliminates the environmental harm while maintaining the essential bonding functionality through the alternative alloy formulation.
Solution Approach 2:
The invention changes the chemical composition parameters of the solder from lead-based to lead-free Sn-Bi-based alloy. This parameter change eliminates environmental harm while preserving manufacturing feasibility through established soldering processes adapted to the new alloy composition.
4Manufacturing precision
If stabilizing layer thickness is reduced to several microns, then superconductive wire-material structure is optimized, but excessive heat during soldering erodes the stabilizing layer
Solution Approach 1:
The invention changes the thermal and chemical parameters of the soldering process by using a Sn-Bi-based alloy with lower melting point and reduced thermal aggressiveness compared to conventional solders. This parameter change allows effective bonding while preventing erosion of the thin stabilizing layer.
Solution Approach 2:
The Sn-Bi-based solder acts as an intermediary material that mediates between the bonding requirement and the protection of the thin stabilizing layer. It provides the necessary bonding function while its specific composition properties prevent direct thermal and chemical erosion of the silver stabilizing layer.
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 method stabilizes the superconductive properties of the wire-material, prevents erosion of the stabilizing layer, and allows for environmentally safe manufacturing by using lead-free solders, resulting in high-quality composite superconductive wire-materials.
Implementation Method 1
immersing the thin-film superconductive wire-material and electroconductive tape into and through a solder bath, which bath adopts a solder comprising an Sn (tin)-based alloy including Bi (bismuth)
Data Source
AI summary
A thin film superconductive wire material (16) and an electro conductive tape (15) are immersed in a solder bath (35) containing a solder, which includes Sn(tin) and Bi (bismuth), to bond the thin film superconductive wire material (16) and the electro conductive tape (15) and a composite superconductive wire material (10) is formed.