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Graphene used to rust-proof steel

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May 29, 2012

A piece of steel treated with the graphene varnish, in front of an untreated sample

A piece of steel treated with the graphene varnish, in front of an untreated sample

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Hexavalent chromium compounds are a key ingredient in coatings used to rust-proof steel. They also happen to be carcinogenic. Researchers, therefore, have been looking for non-toxic alternatives that could be used to keep steel items from corroding. Recently, scientists from the University at Buffalo announced that they have developed such a substance. It’s a varnish that incorporates graphene, the one-atom-thick carbon sheeting material that is the thinnest and strongest substance known to exist.

The composite coating was created by a team led by chemists Sarbajit Banerjee and Robert Dennis.

Initially, pieces of steel coated with it lasted for only a few days when placed continuously in brine. Once the dispersion and concentration of graphene within the varnish were tweaked, however, treated steel was able to last for about a month under the same conditions – the brine used in the trials was far saltier than regular seawater, so the steel would reportedly last for much longer in real-world scenarios.

Three versions of the varnish, containing varying amounts of graphene
Three versions of the varnish, containing varying amounts of graphene

Although the exact makeup of the coating isn’t being released, Banerjee believes that “the material’s hydrophobic and conductive properties may help prevent corrosion, repelling water and stunting electro-chemical reactions that transform iron into iron oxide, or rust.” Additionally, it is said to be compatible with the existing hardware at facilities that currently perform chrome electroplating.

The university has applied for a patent for the varnish. Tata Steel, which sponsored the research, already reserves some rights to the technology. The scientists are now working on improving its staying power, and the quality of its finish.

This isn’t the first time that the anti-corrosive qualities of graphene have been explored. Earlier this year, scientists from Nashville's Vanderbilt University reported that they had used a process of chemical vapor deposition to grow graphene directly on copper and nickel surfaces. When subjected to corrosive elements, the metals respectively corroded seven and 20 times slower than untreated samples.

Source: University at Buffalo

About the Author
Ben Coxworth An experienced freelance writer, videographer and television producer, Ben's interest in all forms of innovation is particularly fanatical when it comes to human-powered transportation, film-making gear, environmentally-friendly technologies and anything that's designed to go underwater. He lives in Edmonton, Alberta, where he spends a lot of time going over the handlebars of his mountain bike, hanging out in off-leash parks, and wishing the Pacific Ocean wasn't so far away.   All articles by Ben Coxworth
8 Comments

How does epoxy paint compare to graphene as a coating for steel soaked in brine for a month?

David Charles Wallace
29th May, 2012 @ 08:19 pm PDT

Have scientists figured out why Iron pillar of Delhi India doesn't rust?

Gregg Eshelman
30th May, 2012 @ 02:31 pm PDT

I wonder what would happen if graphene was mixed into the molten steel?

Billy Brooks
30th May, 2012 @ 03:20 pm PDT

@ Billy most probably just regular high carbon steel

Michael Vassallo
31st May, 2012 @ 10:14 am PDT

Gregg: Maybe the air is very dry in Delhi. Surely someone could take a sample and analyse it?

I think they have solved the problem of steel rusting. Cars don't rust much these days.

Does anyone know how long nanotubes are? As they are only one atom thick, they are practically invisible.

windykites1
1st June, 2012 @ 09:58 am PDT

@Gregg.....Yes, they have. It has a 'high phosphorus content conferring protection by the formation of an even layer of crystalline iron hydrogen phosphate' [http://en.wikipedia.org/wiki/Iron_pillar_of_Delhi]

Vincent Najger
1st June, 2012 @ 11:39 pm PDT

@ Windykites1: Wikipedia has reference's which states many Indian Universities who have anaylized the pillars composition and replicated the Iron pillars manufacture and compsition. The main reason is Phosphorous which is removed from Iron today, because it makes Iron too soft to use in tools and we now have anodising coatings.

This formulae of Iron manufacture must have been chosen exactly because of its longlevity.

L1ma
2nd June, 2012 @ 01:39 pm PDT

stainless steel. more expensive then reg steel, not good for everything. But I think under used. Study showed a bus with stainless steel frame (ss is stronger then reg steel) and few other changes in materials (like for doors) could reduce the weight of a city bus by almost 50%. Which leads to fuel savings, not to mention longevity of vehicle as it would be fairly rust proof.

telocity
5th June, 2012 @ 12:31 pm PDT
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