Superconducting Wire Stabilizer RRR via Impurity Compounds

Solution Overview

Problem

Current methods for producing superconducting wires with high residual resistance ratio (RRR) are complex and costly, as they require extremely high-purity copper and precise control of impurities, making it difficult to achieve stable and efficient production.

Innovation Solution

Incorporating small amounts of Ca, Sr, Ba, and rare earth elements into copper to form compounds with S, Se, and Te, which are unavoidable impurities, to improve the RRR of the stabilizer material, allowing for a simpler and less expensive production process while maintaining high thermal stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If ultra-high purity copper (99.999% or more) is used to achieve high residual resistance ratio, then the RRR performance is improved, but the production process becomes extremely complex and production costs greatly increase

Engineering Contradiction:

Improveresidual resistance ratioVSAvoidproduction process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces expensive ultra-high purity copper (99.999% or more) with cheaper high-purity copper (99.99% or more) containing controlled impurities. By intentionally adding small amounts of specific elements (Al: 0.01-1.0 ppm, Si: 0.01-1.0 ppm, Fe: 0.01-1.0 ppm, and unavoidable impurities totaling 1-50 ppm), the patent achieves high RRR (200 or more) without requiring extremely complex purification processes, thus reducing production costs and process complexity while maintaining reliable electrical performance

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the chemical composition parameters of the copper stabilizer material by precisely controlling the concentrations of specific impurity elements and unavoidable impurities. Instead of requiring 99.999% purity, the patent defines specific ranges for Al (0.01-1.0 ppm), Si (0.01-1.0 ppm), Fe (0.01-1.0 ppm), and total unavoidable impurities (1-50 ppm), which transforms the production approach from extreme purification to controlled composition, simplifying the manufacturing process while achieving RRR of 200 or more

Inventive Principle:

Principle #35Parameter changes

2Reliability

If ultra-high purity copper is used to achieve high residual resistance ratio, then the RRR performance is improved, but the production costs greatly increase

Engineering Contradiction:

Improveresidual resistance ratioVSAvoidproduction cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive ultra-high purity copper (99.999% or more) with cheaper high-purity copper (99.99% or more) containing controlled impurities. By intentionally adding small amounts of specific elements (Al: 0.01-1.0 ppm, Si: 0.01-1.0 ppm, Fe: 0.01-1.0 ppm, and unavoidable impurities totaling 1-50 ppm), the patent achieves high RRR (200 or more) without requiring extremely complex purification processes, thus reducing production costs and process complexity while maintaining reliable electrical performance

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the chemical composition parameters of the copper stabilizer material by precisely controlling the concentrations of specific impurity elements and unavoidable impurities. Instead of requiring 99.999% purity, the patent defines specific ranges for Al (0.01-1.0 ppm), Si (0.01-1.0 ppm), Fe (0.01-1.0 ppm), and total unavoidable impurities (1-50 ppm), which transforms the production approach from extreme purification to controlled composition, simplifying the manufacturing process while achieving RRR of 200 or more

Inventive Principle:

Principle #35Parameter changes

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 approach results in a superconducting wire with a residual resistance ratio of 250 or more, enabling stable operation and cost-effective production, even under varying temperature conditions, by effectively fixing S, Se, and Te as compounds within the copper matrix.

Implementation Method 1

contains one kind or two kinds or more of additive elements selected from Ca, Sr, Ba, and rare earth elements (RE) for a total amount of 3 ppm by mass or more and 400 ppm by mass or less... compounds including one kind or two kinds or more selected from CaS, CaSO4, SrS, SrSO4, BaS, BaSO4, (RE)S, and (RE)2SO2 are present in the matrix

Methodology Applied

Scientific EffectCompound formation: Chemical Bonding

Data Source

PatentUS10971278B2Superconducting wire and superconducting coil

Publication Date: 2021.04.06 MITSUBISHI MATERIALS CORP

AI summary

This superconducting wire includes: a strand including a superconducting material; and a stabilizer material for superconductor arranged in contact with the strand, wherein the stabilizer material for superconductor includes a copper material which contains one kind or two kinds or more of additive elements selected from Ca, Sr, Ba, and rare earth elements (RE) for a total amount of 3 ppm by mass or more and 400 ppm by mass or less, with the remainder being Cu and unavoidable impurities, the total concentration of the unavoidable impurities other than O, H, C, N, and S, which are gas components, is 5 ppm by mass or more and 100 ppm by mass or less, and compounds including one kind or two kinds or more selected from CaS, CaSO4, SrS, SrSO4, BaS, BaSO4, (RE)S, and (RE)2SO2 are present in the matrix.