Ceramic Barrier Layer for HTS Tape Substrate Oxidation Protection

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Solution Overview

Problem

High-temperature superconductor (HTS) production faces challenges in protecting the reverse side of strip-shaped substrates from oxidative damage during crystallization annealing or pyrolysis, which can impair mechanical and electrical properties and disrupt electrical coupling.

Innovation Solution

A ceramic barrier layer with a different chemical composition and/or texture than the buffer layer on the front side is applied to the metallic substrate's underside, using chemical solution deposition methods like CSD, to prevent oxidation and maintain mechanical and electrical integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the metallic substrate is exposed during HTS crystallization annealing or pyrolysis, then the superconducting layer can be formed, but the substrate suffers oxidative damage that impairs mechanical and electrical properties

Engineering Contradiction:
Improvesuperconducting layer formationVSAvoidoxidative damage to substrate
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A ceramic barrier layer is introduced as an intermediary between the metallic substrate and the oxidizing atmosphere during HTS crystallization annealing or pyrolysis. This barrier layer prevents oxygen from reaching and oxidizing the substrate, thereby protecting mechanical and electrical properties while allowing the superconducting layer to form on the front side.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The substrate surface is segmented into two distinct sides with different functionalities: the front side (first longitudinal side) is exposed for superconducting layer formation, while the back side (second longitudinal side) is protected by a ceramic barrier layer during thermal processing. This segmentation allows simultaneous achievement of superconducting layer formation and substrate protection.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If the ceramic barrier layer has the same composition as the buffer layer, then manufacturing is simplified, but electrical coupling is disrupted

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidelectrical coupling
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The ceramic barrier layer on the back side of the substrate is given a different chemical composition and/or texture compared to the buffer layer on the front side. This local differentiation allows the barrier layer to provide oxidation protection while maintaining electrical coupling properties, as the specific composition is selected to be electrically conductive or semi-conductive.

Inventive Principle:
Principle #3Local quality

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 ceramic barrier layer effectively protects the substrate from oxidative processes, preserving mechanical and electrical properties and allowing controlled oxygen partial pressure, ensuring the substrate's strength and conductivity are maintained.

Implementation Method 1

protecting the substrate against oxidation

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 2

protects the substrate from oxidative processes

Methodology Applied
Scientific EffectDiffusion barrier: Diffusion Barrier

Implementation Method 3

using chemical solution deposition methods like CSD

Methodology Applied
Scientific EffectChemical solution deposition: Chemical Vapour Deposition

Implementation Method 4

during the pyrolysis

Methodology Applied
Scientific EffectPyrolysis: Pyrolysis

Implementation Method 5

crystallization annealing

Methodology Applied
Scientific EffectCrystallization: Crystallisation

Implementation Method 6

crystallization annealing or pyrolysis

Methodology Applied
Scientific EffectAnnealing: Annealing

Data Source

PatentEP3175463B1Precursor and method for producing a tape-shaped high-temperature superconductor
Publication Date: 2019.09.11 BASF SE
  • EP3175463B1 patent drawingFigure 1

AI summary

The present invention relates to an pre-product (1) for producing a strip-like high-temperature superconductor (HTS), comprising a metallic strip-like substrate (10) which has a first strip side (11) and a second strip side (12), wherein on the first strip side (11) (a) the substrate (10) has a predefined texture as a template for a crystallographically oriented growth of a buffer layer or an HTS layer and (b) there is an exposed surface of the substrate (10) or there are one or more layers (20, 30) which are chosen from the group consisting of: buffer precursor layer, pyrolyzed buffer precursor layer, buffer layer, HTS precursor layer, pyrolyzed HTS buffer precursor layer and pyrolyzed and further compressed HTS buffer precursor layer, and on the second strip side (12) there is at least one ceramic barrier layer (40) protecting the substrate (10) from oxidation or a precursor which transforms into such during HTS crystallization annealing or pyrolysis, wherein if on the first strip side (11) there are one or more layers (20, 30), the ceramic barrier layer (40) or precursor thereof has a chemical composition and/or a texture different from those of the layer (20) on the first strip side (11) immediately adjacent to the substrate (10). In this case, the barrier layer (40) is a layer which is made of conductive ceramic material and delays or hinders the access of oxygen to the second strip side (12) or a precursor which transforms into such during HTS crystallization annealing or pyrolysis and the ceramic material is an electrically conductive metal oxide or an electrically conductive mixture of metal oxides, wherein the conductive metal oxide or one or more metal oxides in the conductive mixture is preferably a metal oxide doped with a foreign metal.