Electrode Surface Roughening via Patterned Roller Skin-Passing
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Solution Overview
Problem
Existing methods for imparting roughness to metal electrodes for electrochemical applications, such as sand or grit blasting, face challenges including contamination, difficulty in controlling roughness quality, lack of reproducibility, and high disposal costs, which affect the adherence of catalytic layers and lead to mechanical stress and deformation, especially in thin metal sheets.
Innovation Solution
The method involves skin-passing metal sheets between rollers with a negative image of the desired roughness profile, allowing for a predefined and reproducible surface roughness pattern to be imparted, which is achieved by patterning the rollers using techniques like blasting, photoetching, or laser inscribing, and subsequent hardening to maintain planarity and extend roller life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If sand or grit blasting is used to impart roughness to the metal surface, then surface roughness is achieved, but the surface becomes contaminated with particles that negatively affect catalytic layer adherence
Solution Approach 1:
The patent introduces an intermediary substance (slurry containing abrasive particles suspended in liquid) between the blasting medium and the metal surface. This slurry allows the abrasive particles to create the desired roughness profile while the liquid carrier prevents particle contamination by enabling easy removal of loose particles from the surface, thus resolving the contradiction between achieving roughness and avoiding contamination that would harm catalytic layer adherence
Solution Approach 2:
The patent changes the physical state and composition parameters of the blasting medium from dry sand/grit to a wet slurry suspension. This parameter change allows the same abrasive particles to function effectively for creating roughness while the liquid medium provides a cleaning effect, preventing contamination and ensuring surface readiness for catalytic layer application
2Shape
If thick metal sheets are subjected to mechanical blasting, then surface roughness is achieved, but hardness increase leads to cracks during catalytic layer application
Solution Approach 1:
The patent modifies the blasting parameters by using a wet slurry medium with controlled particle size distribution and impact velocity. This parameter change reduces the severity of mechanical impact on the metal surface, achieving the necessary roughness profile while minimizing hardness increase that would otherwise lead to cracking during subsequent catalytic layer application
3Shape
If sand or grit blasting is used, then surface roughness is achieved, but the sand or grit stock must be discharged after working hours due to particle size decrease, increasing disposal costs
Solution Approach 1:
The patent implements a system where the slurry can be separated into liquid and solid components after use. The abrasive particles can be recovered from the liquid carrier through sedimentation or filtration, cleaned of metal contaminants, and reused in subsequent blasting operations. This recovery process eliminates the need to discharge the entire sand or grit stock after each working period, significantly reducing disposal costs and improving sustainability
Solution Approach 2:
The patent changes from using dry particulate material to a liquid-based slurry system. This parameter change enables the abrasive particles to be suspended and transported in the liquid medium, allowing for easier separation and recovery of the particles after use. The liquid carrier facilitates particle recovery processes that would be difficult or impossible with dry blasting media, thereby reducing waste and disposal 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 ensures a clean, reproducible surface roughness that enhances the adherence of catalytic layers, reduces mechanical stress, and maintains planarity, even in thin sheets, while simplifying and cost-reducing the manufacturing process by minimizing deformation and extending roller lifespan.
Implementation Method 1
imprint a surface roughness profile pattern to at least one major surface of a metal sheet by skin-passing the metal sheet between two rollers of a rolling mill, at least one of the rollers being provided with a negative image of the roughness profile pattern
Implementation Method 2
skin-passing the metal sheet between two rollers of a rolling mill
Implementation Method 3
subsequent hardening to maintain planarity and extend roller life
Data Source
AI summary
The invention relates to a method for roughening the surface of a metal sheet used as electrode support in industrial electrochemical applications, and an electrode made by such method. Mechanical roughening is imparted by skin-passing the sheet between two rollers of a rolling mill, at least one of which is patterned according to a predetermined profile to be transferred by compression to the surface of the metal sheet.