Hydrophobic Fluoropolymer Coating for Anodic Film Crack Sealing
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Solution Overview
Problem
Anodic films on metal substrates, such as aluminum, develop micro-cracks due to thermal expansion differences between the film and the substrate, allowing moisture and contaminants to enter and cause corrosion, especially after laser marking processes.
Innovation Solution
Applying a hydrophobic fluoropolymer coating using a spray-on technique to fill and seal the cracks within the anodic film, preventing moisture and contaminants from reaching the underlying metal substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If laser marking process is applied to anodized metal substrate, then aesthetic and functional markings are achieved, but micro-cracks form in the anodic film allowing moisture and contaminants to reach the metal substrate causing corrosion
Solution Approach 1:
A hydrophobic coating is applied as an intermediary layer between the anodic film and the external environment. This coating specifically targets and seals the micro-cracks created by laser marking, preventing moisture and contaminants from reaching the metal substrate while preserving the laser-marked aesthetic appearance and functionality.
Solution Approach 2:
The patent changes the surface energy parameters of the anodic film by applying a hydrophobic coating. This parameter change transforms the surface from hydrophilic to hydrophobic, causing water and polar contaminants to bead up and roll off rather than penetrate into the micro-cracks, thereby maintaining corrosion resistance despite the presence of cracks.
2Reliability
If anodic film is formed on metal substrate to provide corrosion resistance, then the substrate gains protective coating, but thermal expansion differences cause micro-cracks that compromise the protective function
Solution Approach 1:
The hydrophobic coating is applied in advance to seal the micro-cracks before they can allow moisture and contaminants to penetrate. This preliminary protective action prevents the formation of corrosion pathways, addressing the integrity issue caused by thermal expansion differences before they can compromise the protective function.
Solution Approach 2:
The patent converts the harmful effect of micro-cracks into a beneficial outcome by applying a hydrophobic coating that specifically targets these cracks. The cracks, which would normally be defects compromising protection, become sealed channels that demonstrate where the hydrophobic coating provides its most critical protective function, thereby converting the structural weakness into a showcase for the effectiveness of the hydrophobic treatment.
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 hydrophobic coating effectively seals the cracks, preventing corrosion and maintaining the aesthetic and functional integrity of the anodized surfaces, even after wear and tear, by repelling water and other contaminants.
Implementation Method 1
a polymerized hydrophobic material infused within the channel so as to prevent ingress to the metal substrate
Implementation Method 2
The fluoropolymer material prevents liquid from entering the crack and reaching the metal substrate
Implementation Method 3
The spray nozzle is configured to create a stream of atomized precursor material of a fluoropolymer material
Implementation Method 4
The anodic films are formed by exposing a metal substrate to an anodizing process, whereby a portion of the substrate is converted to its corresponding metal oxide
Implementation Method 5
the differences in thermal expansion of the anodic film, which is generally amorphous similar to glass, and the underlying metal substrate. In particular, the metal substrate will expand more than the anodic film when exposed to heat
Data Source
AI summary
Coatings for filling cracks within anodic films formed from, for example, a laser marking process are described. The cracks generally have widths of nanometers in scale and can extend from an external surface of an anodic film to an underlying metal substrate. The coatings fill the cracks to prevent liquid and contaminants from entering the cracks and reaching the metal substrate, thereby preventing corrosion of the underlying metal substrate. The coatings can be hydrophobic such that water is wicked away from the cracks. In some cases, the coatings are fluoropolymer coatings. Methods include spray-on techniques that provide a thin and uniform layer of the coating. The spray-on technique can be configured to spray on a fluoropolymer precursor onto the anodic film such that the fluoropolymer precursor diffuses into and polymerizes into the fluoropolymer coating within the cracks.