Copper Substrate Biaxial Texture via Sputter Etching

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Solution Overview

Problem

Existing methods for manufacturing metal laminated substrates for oxide superconducting wires face issues with insufficient copper orientation, surface scratches, and texture degradation due to rolling, leading to compromised superconducting properties.

Innovation Solution

A method involving sputter etching of copper and nonmagnetic metal sheets at temperatures below the crystal orientation temperature, followed by bonding with controlled pressure and subsequent heat treatment to achieve high copper orientation and prevent surface damage, while ensuring adhesion and maintaining the crystal state of copper.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If copper is laminated to stainless steel substrate and biaxially textured, then adhesion is improved, but copper orientation becomes insufficient and scratches form on copper surface

Engineering Contradiction:
ImproveadhesionVSAvoidcopper orientation
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The copper foil is subjected to sputter etching treatment before lamination to remove absorbed materials and activate the surface. This preliminary action improves adhesion without requiring subsequent rolling that would degrade the copper texture, thus resolving the contradiction between adhesion and orientation preservation

Inventive Principle:
Principle #10Preliminary action

2Strength

If textured copper is laminated to stainless steel by cold rolling, then adhesion is enhanced, but copper texture is degraded and scratches are formed

Engineering Contradiction:
ImproveadhesionVSAvoidcopper texture
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

Sputter etching is performed on the copper foil before lamination to activate the surface and remove absorbed materials. This preliminary surface treatment provides sufficient adhesion without requiring aggressive cold rolling, thereby preserving the copper texture and avoiding scratches

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The conventional mechanical cold rolling process for achieving adhesion is replaced with a sputter etching-based bonding approach. This substitution eliminates the mechanical deformation that degrades copper texture while maintaining strong adhesion between layers

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If copper is subjected to high rolling reduction and biaxially textured, then copper orientation is improved, but scratches and grooves form on copper surface

Engineering Contradiction:
Improvecopper orientationVSAvoidsurface scratches
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

Sputter etching is performed as a preliminary treatment to activate the copper surface and remove absorbed materials. This allows the copper to achieve proper adhesion and orientation through controlled bonding rather than aggressive rolling, thus preventing surface scratches while maintaining copper orientation

Inventive Principle:
Principle #10Preliminary action

4Strength

If nickel layer is laminated to copper, then superconducting layer adhesion is improved, but copper texture and superconducting properties are deteriorated

Engineering Contradiction:
ImproveadhesionVSAvoidsuperconducting properties
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The copper foil undergoes sputter etching treatment before lamination, which activates the surface for better adhesion. This preliminary activation allows subsequent layers (nickel and superconducting layer) to bond effectively without requiring aggressive rolling that would degrade copper texture and harm superconducting properties

Inventive Principle:
Principle #10Preliminary action

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 highly oriented copper substrates with improved adhesion and reduced surface defects, enhancing the superconducting properties by maintaining the crystal state and texture integrity during the manufacturing process.

Implementation Method 1

removing, in a state where a copper foil to which rolling is applied at a draft of 90% or more is held at a temperature below a crystal orientation temperature, an absorbed material on a surface of the copper foil by applying sputter etching to the surface of the copper foil

Methodology Applied
Scientific EffectSputter etching: Sputtering

Implementation Method 2

biaxial texture of the copper by heating a laminate obtained by bonding at a crystal orientation temperature of copper or above

Methodology Applied
Scientific EffectHeat treatment: Heat Treatment

Implementation Method 3

biaxial texture of the copper by heating a laminate obtained by bonding at a crystal orientation temperature of copper or above

Methodology Applied
Scientific EffectCrystal orientation: Crystallisation

Data Source

PatentEP2455949B1Metal laminated substrate for use as an oxide superconducting wire material, and manufacturing method therefor
Publication Date: 2016.08.31 TOYO KOHAN CO LTD
  • EP2455949B1 patent drawingFigure 1~2
  • EP2455949B1 patent drawingFigure 3~4
  • EP2455949B1 patent drawingFigure 5

AI summary

Provided are a method of manufacturing a metal laminated substrate for an oxide superconducting wire and a metal laminated substrate for an oxide superconducting wire, where copper can have sharp biaxial texture and the formation of scratches and grooves on a surface of copper can be prevented. The method includes the steps of: removing, in a state where a copper foil to which rolling is applied at a draft of 90% or more is held at a temperature below a recrystallization temperature, an absorbed material on a surface of the copper foil by applying sputter etching to the surface of the copper foil; removing an absorbed material on a surface of a nonmagnetic metal sheet by applying sputter etching to the surface of the nonmagnetic metal sheet; bonding the copper foil and the metal sheet to each other by reduction rolls at an applied pressure of 300MPa to 1500MPa; orienting crystals of the copper by heating a laminated body obtained by bonding at a crystal orientation temperature of copper or above; and forming a protective layer on a copper-side surface of the laminated body by coating.