Oxide Superconductor Filament Grooving via Laser Ablation
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Solution Overview
Problem
Existing methods for forming a multi-filament structure in rare-earth-based oxide superconducting wires face challenges such as limited groove width reduction, over-etching, and poor insulation resistance due to thermal processing and etching techniques, which affect critical current and peeling of superconducting filaments.
Innovation Solution
The use of an excimer laser with a uniform intensity distribution in the ultraviolet region to form dividing grooves that reach the intermediate layer but not the substrate, ensuring high insulation resistance between filament conductors by covering the groove walls with an insulating coating layer formed from the intermediate and oxide superconducting layer constituents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If chemical etching is used to form dividing grooves, then the oxide superconducting layer can be divided, but the groove width becomes wider than 100 μm and over-etching occurs
Solution Approach 1:
The patent replaces chemical etching with laser irradiation to form dividing grooves. The laser beam (1030 nm fiber laser or 1064 nm solid-state laser) directly ablates or melts the oxide superconducting layer and metal stabilizing layer to create precise grooves without chemical over-etching, achieving groove widths of 100 μm or less while maintaining clean edges and preventing peeling.
Solution Approach 2:
The patent changes the processing method from chemical to physical (laser) and adjusts laser parameters (wavelength, pulse duration, power, scanning speed) to control groove dimensions. By optimizing these parameters, the groove width is precisely controlled at 100 μm or less, and groove depth is controlled to stop at the intermediate layer without reaching the substrate, eliminating over-etching issues.
2Ease of manufacture
If laser irradiation in the far-infrared region (1030 nm) is used to divide the oxide superconducting layer, then dividing grooves can be formed, but thermal processing reduces critical current
Solution Approach 1:
The patent utilizes phase transition (melting and vaporization) of materials under laser irradiation to form dividing grooves. The laser energy causes localized melting and subsequent ejection of molten material, creating clean grooves without excessive thermal diffusion that would damage superconducting properties. The rapid cooling after laser passage prevents thermal degradation.
Solution Approach 2:
The patent employs pulsed laser irradiation instead of continuous laser. The periodic pulse structure allows heat to dissipate between pulses, preventing cumulative thermal damage to the superconducting layer while still achieving effective material removal during each pulse. This pulsed action maintains critical current by limiting thermal exposure.
3Reliability
If picosecond laser with Gaussian intensity distribution is used, then thermal processing effect is reduced, but cutting depth is non-uniform and insulation resistance is insufficient
Solution Approach 1:
The patent addresses the Gaussian intensity distribution issue by intentionally designing an asymmetric groove profile or using asymmetric scanning strategies. The laser parameters are optimized so that the deeper cut at the center is compensated by controlling the groove shape, or multiple passes are used to achieve uniform effective cutting depth across the groove width, ensuring consistent insulation resistance.
Solution Approach 2:
The patent implements process control through monitoring and adjustment of laser parameters based on observed groove characteristics. By measuring groove depth and width during processing and adjusting laser power, pulse duration, or scanning speed in real-time, uniform cutting depth is achieved across the entire groove region, ensuring adequate insulation resistance between filaments.
4Manufacturing precision
If multiple laser irradiation operations (20-30 times) are performed to form uniform dividing grooves, then groove uniformity is improved, but productivity decreases
Solution Approach 1:
The patent achieves uniform dividing grooves in a single continuous laser irradiation pass by optimizing the laser parameters (power, pulse duration, scanning speed, focal position) from the outset. The continuous action with properly tuned parameters eliminates the need for multiple repeated operations, maintaining groove uniformity while dramatically improving productivity.
Solution Approach 2:
The patent performs preliminary optimization of laser processing parameters before actual production. Through pre-experiments, the optimal parameter combination is determined that achieves uniform groove formation in one pass. This preliminary setup ensures that subsequent production runs require minimal repetitions, balancing groove quality with manufacturing efficiency.
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 achieves high insulation resistance and maintains the superconducting properties of the oxide superconducting layer, reducing AC loss and improving peel strength by eliminating over-etching and ensuring uniform groove depth, with resistance values exceeding 1 MΩcm between adjacent filaments.
Implementation Method 1
The use of an excimer laser with a uniform intensity distribution in the ultraviolet region to form dividing grooves
Data Source
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AI summary
An oxide superconductor includes: a substrate made of a metal; an insulating intermediate layer provided on the substrate; an oxide superconducting layer provided on the intermediate layer; a metal stabilizing layer provided on the oxide superconducting layer; and a plurality of dividing grooves which divide the metal stabilizing layer and the oxide superconducting layer along a longitudinal direction of the substrate, reach the inside of the intermediate layer through the oxide superconducting layer from the metal stabilizing layer, and do not reach the substrate. The metal stabilizing layer and the oxide superconducting layer are divided to form a plurality of filament conductors by the plurality of dividing grooves, and in each dividing groove of the plurality of dividing grooves, a width of a groove opening portion of the dividing groove is equal to or greater than a width of a groove bottom portion of the dividing groove.