Graphene films—highly resistant to damage—could protect metals in harsh environments

Sep 27, 2012
A graphene coating can make copper nearly 100 times more resistant to corrosion. Credit: Derek Lobo

(Phys.org)—A coating so thin it's invisible to the human eye has been shown to make copper nearly 100 times more resistant to corrosion, creating tremendous potential for metal protection even in harsh environments.

In a paper published in the September issue of Carbon, researchers from Monash University and Rice University in the USA say their findings could mean paradigm changes in the development of anti-corrosion coatings using extremely thin graphene films.

Graphene is a microscopically thin layer of . It is already in use in such things as smartphone screens, and is attracting research attention for its possibilities as a means of increasing metal's resistance to corrosion.

"We have obtained one of the best improvements that have been reported so far," said study co-author Dr Mainak Majumder. "At this point we are almost 100 times better than untreated copper. Other people are maybe five or six times better, so it's a pretty big jump."

Dr Parama Banerjee, who performed most of the experiments for this study, said graphene had excellent and great strength.

The that are often used on metals can be scratched, compromising their protective ability, but the invisible layer of graphene – although it changes neither the feel nor the appearance of the metal – is much harder to damage.

"I call it a magic material," Dr Banerjee said.

The researchers applied the graphene to copper at temperatures between 800 and 900 degrees, using a technique known as , and tested it in .

"In nations like Australia, where we are surrounded by ocean, it is particularly significant that such an atomically thin coating can provide protection in that environment," Dr Banerjee said.

Initial experiments were confined to copper, but Dr Banerjee said research was already under way on using the same technique with other metals.

This would open up uses for a huge range of applications, from ocean-going vessels to electronics: anywhere that metal is used and at risk of corrosion. Such a dramatic extension of metal's useful life could mean tremendous cost savings for many industries.

The process is still in the laboratory-testing stage, but Dr Majumder said the group was not only looking at different metals, but also investigating ways of applying the coating at lower temperatures, which would simplify production and enhance market potential.  

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User comments : 12

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gopher65
5 / 5 (2) Sep 27, 2012
This is awesome:).
antialias_physorg
5 / 5 (1) Sep 27, 2012
It will be interesting how this scales with the number of graphene layers - and what will be the optimum layer thickness.
ScooterG
1 / 5 (1) Sep 27, 2012
It will be interesting how this scales with the number of graphene layers - and what will be the optimum layer thickness.


I was wondering the same thing, thinking about copper and brass plumbing products. And I wonder how it would hold up to acidic liquids, such as found in canned tomatoes?
ddietle
not rated yet Sep 27, 2012
I wonder how it would hold up to acidic liquids, such as found in canned tomatoes?

Hopefully well. Graphene doesn't seem to be very reactive, and since it isn't a base, I bet it will do wonders. Now, if we could just find a way to scrub the excess carbon in the atmosphere, we could kill two birds with one stone.
ddietle
not rated yet Sep 27, 2012
Scooter, I just happened to be reading the wikipedia page on carbon and found this:
It does not react with sulfuric acid, hydrochloric acid, chlorine or any alkalis.


So apparently it would do an awesome job.
antialias_physorg
5 / 5 (2) Sep 27, 2012
Now, if we could just find a way to scrub the excess carbon in the atmosphere, we could kill two birds with one stone.

I doubt it. After screwing around a bit with numbers I found (unless I miscalculated) that if you were to cover the entire Earth surface with a single layer of graphene you'd need roughly 3*10E5 tons.
The carbon in the atmophere as CO2, by weight, is about 1.3*10E21 tons (the weight of the oxygen atoms is already deducted).

So even if you'd take all the carbon for that graphene coat out of the atmosphere you'd only have removed
0.000000000000023 percent.
ScooterG
3.7 / 5 (3) Sep 27, 2012
Scooter, I just happened to be reading the wikipedia page on carbon and found this:
It does not react with sulfuric acid, hydrochloric acid, chlorine or any alkalis.


So apparently it would do an awesome job.


Awesome indeed. Maybe this will allow us to get bisphenol-A (BPA) out of our food supply.
sstritt
1 / 5 (1) Sep 27, 2012
Awesome indeed. Maybe this will allow us to get bisphenol-A (BPA) out of our food supply.

My thoughts exactly, although we need to find a substitute for thermal paper as well (BPS not looking so good)
islatas
5 / 5 (1) Sep 27, 2012
...if you were to cover the entire Earth surface with a single layer of graphene...


We have enough paper to cover the world over many times yet we keep pressing it. I don't think that comparison is relevant.
ScooterG
3.7 / 5 (3) Sep 27, 2012
It might also be a replacement for galvanizing on mild steel, or any sort of paint primer. I was also wondering if it might have a place in cathodic protection for underground pipelines?

These researchers are on to something huge. And we have lots and lots of carbon at our disposal.
antialias_physorg
not rated yet Sep 27, 2012
We have enough paper to cover the world over many times yet we keep pressing it. I don't think that comparison is relevant.

I'm sure that we can use more graphene than covers the Earth. But that much more? We're not talkin 10 or 100 or even a billion times more. We're talking 14 orders of magnitude if we want to reduce the carbon content in the atmosphere even by a single percent of what it currently is.
scatter
1 / 5 (1) Sep 27, 2012
^With 14 orders of magnitude to cover, we'd need to start shooting grapite flakes into space or something or we'd be coating things with graphite.. (assuming "human sized" objects with low surface to volume ratio compared to microscopic things)