Materials

Self-healing coating protects metals from corrosion

Self-healing coating protects ...
The technology could be used to help keep structures such as bridges from corroding 
The technology could be used to help keep structures such as bridges from corroding 
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The technology could be used to help keep structures such as bridges from corroding 
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The technology could be used to help keep structures such as bridges from corroding 

Corrosionin metals can lead to the structural fatigue or failure of bridges,pipelines, and plane fuselages. Anti-corrosion coatings help preventthis, but they become ineffective when pierced, cracked, or scratchedaway. Researchers at Northwestern University have now developed aself-healing coating that can patch up its imperfections in a matterof seconds.

"Localcorrosion in metal is quite dangerous because it is hard to predict,and when it happens, oftentimes it is hard to detect, thus leftunattended," Prof. Jiaxing Huang, who led the research efforts, told NewAtlas. "There are [detection] methods based on visual inspection,or techniques such as those based on electrochemistry to monitor therate of corrosion. But because corrosion is local, finding the spotsin a large metal structure is not easy."

We'vealready seen self-healing coatings powered by the Sun and others inspired by a snake's skin, but these can only repair microscopic defects.In order to heal bigger imperfections on the millimeter scale, Huangand his colleagues took a different inspiration.

"Whena boat cuts through water, the water goes right back together,"says Huang. "The 'cut' quickly heals because water flowsreadily. We were inspired to realize that fluids, such as oils, arethe ultimate self-healing system."

Theoil-based coating had to be fluid enough to quickly self-repair in amatter of seconds, but not so liquid that it would simply drip offthe metal's surface. The "Goldilocks zone" was achieved by addingmicroscopic and lightweight graphene capsules which thicken the oiland help it stick to the metal extremely well even in harshenvironments, whether underwater or in acid baths.

Thescientists showed that the material can heal quickly and repeatedly,even after scratching the same spot for 200 times in a row, on anumber of different metals including aluminum, brass, and steel.Huang tells us that the coating should in principle work with anymetal, since it is not based on a specific surface chemistry.

Nextup, the researchers will work on anti-fouling coatings and findingways to mass-produce their graphene capsules.

Thecoating is further described in the video below.

Fluid-inspired metal coating self-heals before your eyes

Source:Northwestern University

5 comments
jerryd
Corten? steel has been doing this for 50+ yrs now, no coating needed.
Douglas Bennett Rogers
Looks like it might have a wear problem.
c4jjm
Unbelievable...this is nothing new! It took real geniuses to figure this one out! Like Jerryd said, others have been doing this all along...the reason this never went anywhere, is that the environment wouldn't like it, inevitably it will fall off, it will contaminate groundwater, soil, what ever it is near.....also, with any gel like substance, it will be easy to wipe away...this is only good at protecting steel as long as there is ZERO mechanical abrasion....which for bridges, this only sort of works, but again, pollution rules it out immediately.
Kpar
Yes, this seems like it might be something different, but there was a type of steel called "Corfam" , I think- the John Hancock Center in Chicago is clad with it. It was designed to corrode, but unlike rust, it doesn't flake off, giving it a protective coating.
john75
They don't say what oils could be used, even food grade mineral oil might work though graphene capsules will likely totally contaminate the food chain before we know it. If combined with surface textures or cowtungs perhaps automotive frames will last decades in the snow belt.