Superconducting Stabilizer Material High Residual Resistance Ratio

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Solution Overview

Problem

The production of superconducting wires with high residual resistance ratio (RRR) stabilizer materials is complex and costly due to the need for ultra-high purity copper and precise control of impurities, and existing methods struggle to maintain a high RRR across a wide temperature range.

Innovation Solution

Incorporating small amounts of Mg into copper to form compounds with unavoidable impurities like S, Se, and Te, which fixes these elements and improves the RRR, allowing for a simpler and less expensive production process while maintaining thermal stability across a wide temperature range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If ultra-high purity copper (99.999% or more) is used to produce stabilizer material with high RRR, then the residual resistance ratio is sufficiently high, 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 invention changes the purity parameter from ultra-high purity (99.999%) to high purity (99.99%), and introduces a new parameter - additive elements (B, Ti, Zr, Hf) at specific concentrations (0.003-0.1 mass%). This parameter transformation resolves the contradiction by achieving high RRR through controlled composition rather than extreme purity, simplifying the production process while maintaining electrical performance

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention transitions from pure copper material to a composite copper alloy system containing base copper (99.94-99.99 mass%) plus controlled impurities and additive elements. This composite approach allows the material to achieve high RRR through the synergistic effect of copper matrix with controlled trace elements, avoiding the need for ultra-high purity copper and its associated complex production processes

Inventive Principle:
Principle #40Composite materials

2Reliability

If ultra-high purity copper is used to produce stabilizer material with high RRR, then the residual resistance ratio is sufficiently high, but the production costs greatly increase

Engineering Contradiction:
Improveresidual resistance ratioVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention changes the purity parameter from ultra-high purity (99.999%) to high purity (99.99%), and introduces a new parameter - additive elements (B, Ti, Zr, Hf) at specific concentrations (0.003-0.1 mass%). This parameter transformation resolves the contradiction by achieving high RRR through controlled composition rather than extreme purity, simplifying the production process while maintaining electrical performance

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses more readily available high purity copper (99.99%) instead of rare ultra-high purity copper (99.999%), making the material more economically accessible. The controlled addition of inexpensive elements like B, Ti, Zr, or Hf further reduces costs while achieving the desired high RRR performance, making the stabilizer material more cost-effective for superconducting wire production

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Reliability

If existing methods are used to produce high RRR stabilizer material, then the residual resistance ratio is improved, but the RRR cannot be maintained across a wide temperature range

Engineering Contradiction:
Improveresidual resistance ratioVSAvoidtemperature stability of RRR
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The invention optimizes the composition parameters by controlling impurity levels (O: 0.005-0.05 mass%, S: 0.003-0.03 mass%) and adding specific elements (B, Ti, Zr, Hf: 0.003-0.1 mass%) that stabilize the copper lattice structure across temperature variations. This compositional optimization enables the RRR to remain high and stable across a wide temperature range from 4.2K to 77K, resolving the temperature stability issue

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention establishes compositional feedback control where the presence of specific elements (B, Ti, Zr, Hf) compensates for variations in impurity content and temperature effects. These additive elements act as feedback mechanisms that maintain stable electrical resistance characteristics across temperature changes, ensuring consistent RRR performance through controlled composition rather than extreme purity

Inventive Principle:
Principle #23Feedback

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

The approach results in a stabilizer material with a residual resistance ratio of 250 or more, effectively bypassing current at extremely low temperatures and preventing the transition to a normal conducting state, making it suitable for superconducting wires and coils.

Implementation Method 1

In a copper, one kind or more of additive elements selected from Mg, Mn, Ti, Y, and Zr are contained... compounds including one kind or more selected from MgS and MgSO4 are present in a matrix

Methodology Applied
Scientific EffectChemical Bonding: Chemical Bonding

Data Source

PatentEP3441485B1Stabilizer material for superconductor, superconducting wire and superconducting coil
Publication Date: 2022.06.01 MITSUBISHI MATERIALS CORP
  • EP3441485B1 patent drawingFigure 1~2
  • EP3441485B1 patent drawingFigure 3~4
  • EP3441485B1 patent drawingFigure 5

AI summary

The stabilizer material for superconductor of the present invention is used for a superconducting wire, and the stabilizer material for superconductor includes a copper material, the copper material contains one kind or more of additive elements selected from Mg, Mn, Ti, Y, and Zr for a total amount of 3 ppm by mass or more and 100 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 more selected from MgS, MgSO4, MnS, TiS, YS, Y2SO2, and ZrS are present in the matrix.