17 March 2008

Foam Metals: Lighter than Water and More Uses than You Can Imagine

Scientists are just beginning to find uses for foam metals: metals that are 90% air bubbles, many of which will float on water. One interesting new use was discovered by University of Quebec at Montreal researchers: producing hydrogen from water.
Metafoam Technologies Inc. proudly announces that its metal foam electrodes have yielded promising results for hydrogen production....Metafoam's nickel foams used as porous electrodes in water electrolysis have shown exciting results thanks to their high surface area. Actually, Metafoam's material has reached roughness factors 2 to 25 times higher than standard porous meshes and competing metal foams.____Source__via__NextEnergy
Metal foams can be made to possess a wide range of properties.
Metal foams are a new class of material, as yet imperfectly characterised, but with alluring properties.

They are light and stiff, they have good energy-absorbing characteristics (making them good for crash-protection and packaging) and they have attractive heat-transfer properties (used to cool electronic equipment and as heat exchangers in engines).

Some have open cells (Figure 1), very much like polymer foams but with the characteristics of metals (ductility, electrical conductivity, weld ability, and so forth).

Others have closed cells, like metallic cork.

And they are visually appealing, suggesting use in industrial design.

There are currently some 12 producers marketing a range of metal foams, mostly based on aluminum, but other metals – copper, nickel, stainless steel and titanium – can be foamed and are available on order.

The most promising applications for metal foams appear to be as cores for light-stiff sandwich panels; as stiffeners to inhibit buckling in light shell structures; as energy absorbing units, both inside and outside of motor vehicles and trains; as efficient heat exchanges to cool high powered electronics (by blowing air through the open cells of the aluminum foam, like that of Figure 1, attached to the heat source) and as light cores for shell casting. Several industrial designers have seen potential in exploiting the reflectivity and light-filtering of open cell foams, and the interesting textures of those with closed cells.___Source

The uses for metal foams listed in the above paragraph are clearly already out of date, given the entry of metal foams into the catalysis and electrode business. Many more uses for these interesting materials are waiting to be found.

We at Al Fin have been looking for suitable materials for building "Seasteads"--floating cities on the ocean. Such materials would need to be lightweight but strong, and resistant to corrosive forces common on the sea. It is easy to visualize many areas of seastead construction that might involve the use of closed cell metal foams.

As better forms of molecular manufacturing come on line, we should expect better metal foams, with custom designed surface area ratios, and complex mixes of materials for specific purposes, to be created.

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Blogger Snake Oil Baron said...

Metal foams will no doubt have lots of applications. Material science is having an impressive influence on the world of technology and engineering.

If a version of the foam or composite material can be obtained that is sufficiently strong as well as have the stiffness and low mass properties it might be quite useful in making large scale cargo and cruise blimps.

Monday, 17 March, 2008  
Blogger al fin said...

Interesting idea, Baron.

Currently, these foams are being made in fairly small sizes and quantities, but once production methods are developed to scale up sizes and quantities I suspect more structural uses for these foams will be tested.

Finding ways to maintain the lightness while improving the resistance to various stresses, will make some engineer a lot of money.

Tuesday, 18 March, 2008  
Blogger IConrad said...

If this sort of thing could be made combinitively productive with carbon nanotubes, we could get all the ductility and malleability of metals with the strength characteristics of the carbon nanotube structures...

That's big. That's more than big.

Tuesday, 18 March, 2008  

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