Oxide Superconducting Wire Ag Protective Layer Uniformity
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Solution Overview
Problem
Oxide superconducting wires face issues with pinholes in protective layers, leading to moisture penetration and degradation of superconducting characteristics, especially when Ag is used, as it aggregates and becomes brittle, requiring a solution that limits Ag usage while maintaining protective functionality.
Innovation Solution
An oxide superconducting wire with a protective layer of Ag or Ag alloy, formed with an average thickness of 0.1 µm to 5 µm and a standard deviation ratio of 0.4 or less, is created after oxygen annealing, ensuring uniformity and preventing pinhole formation, and further stabilized with a plating coating layer and metal tape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the protective layer is made thick to prevent pinholes, then the protective function is improved, but the cost increases due to more Ag usage
Solution Approach 1:
The patent changes the parameter of film thickness uniformity by controlling the standard deviation ratio (Tσ/Tave) to be 0.4 or less. This parameter change allows the protective layer to maintain adequate thickness throughout, preventing pinholes without requiring excessive overall thickness, thus reducing Ag usage while maintaining protective function.
Solution Approach 2:
The patent applies oxygen annealing treatment (a thermal-hygrotic process) to the intermediate body before forming the protective layer. This preliminary treatment modifies the substrate properties to enable more uniform Ag deposition, reducing thickness variation and preventing pinhole formation with thinner, more uniform protective layers.
2Quantity of substance
If the protective layer is made thin to reduce cost, then Ag usage is reduced, but pinholes may occur allowing moisture penetration
Solution Approach 1:
The patent changes the parameter of thickness uniformity by controlling the standard deviation ratio (Tσ/Tave) to be 0.4 or less. This ensures that even when the average thickness is reduced to minimize Ag usage, the actual thickness remains sufficiently uniform throughout the layer to prevent pinhole formation and moisture penetration.
Solution Approach 2:
The patent performs oxygen annealing treatment on the intermediate body before depositing the protective layer. This preliminary action prepares the substrate surface and structure to receive the Ag layer more uniformly, enabling thin protective layers to be formed without pinholes, thus maintaining protective function while reducing material usage.
3Object-affected harmful factors
If Ag is used as protective layer material, then reactivity with oxide superconducting layer is reduced, but Ag atoms aggregate during heating forming pinholes
Solution Approach 1:
The patent performs oxygen annealing treatment on the intermediate body before depositing the Ag protective layer. This preliminary action stabilizes the substrate and intermediate layers, creating conditions that prevent Ag atom aggregation during subsequent heating processes, thus maintaining film thickness uniformity while preserving Ag's low reactivity advantage.
Solution Approach 2:
The patent controls the standard deviation ratio (Tσ/Tave) of film thickness to be 0.4 or less by optimizing deposition parameters and preliminary treatment conditions. This parameter control prevents Ag atom aggregation and pinhole formation during heating, maintaining both the low reactivity and manufacturing precision requirements.
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 reduces the cost of the protective layer while maintaining its effectiveness, preventing moisture penetration and maintaining the superconducting characteristics by ensuring a uniform and non-brittle protective layer, thus enhancing the wire's durability and performance.
Implementation Method 1
a protective layer formed on the intermediate body
Implementation Method 2
The oxygen annealing treatment is performed such that the oxide superconducting wire is heated at 300 °C to 500 °C under an oxygen atmosphere
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
An oxide superconducting wire includes an oxide superconducting laminate, the oxide superconducting laminate including: an intermediate body having a tape-shaped substrate, an intermediate layer formed on a main surface of the substrate, and an oxide superconducting layer formed on the intermediate layer; and a protective layer formed on the intermediate body. An average film thickness Tave of the protective layer is 0.1 µm to 5 µm. The ratio Tσ/Tave between a standard deviation Tσ and the average film thickness Tave of a film thickness of the protective layer is 0.4 or less.