[lolc]

The part about shielding radiation sounds dubious to me. I thought shielding from radiation was mostly about mass. How is that foam supposed to shield better than cast metal of the same weight? Maybe the "foam" deteriorates less?

[rdtsc]

> I thought shielding from radiation was mostly about mass.

Not for all types of radiation. Neutron radiation for example is absorbed better by a hydrogen rich material like say polyethylene. But then during absorbtion it would emit gamma rays sometimes, so metal shielding is needed as well.

[dubyah]

They outperformed aluminum because of the iron content in the steel of the sphere walls or the matrix itself of the steel-steel composite metal foam.

The composite metal foam that was comparable to lead utilized steel with higher concentrations of tungsten and vanadium.

[SixSigma]

"foam" is the right way of thinking, it's not some thin bubbles of mostly air, from comment above :

> The metal foam is made of 2mm-diameter hollow steel spheres in a stainless steel matrix (created using powder metallurgy).

[feelix]

if you have something that interrupts the wave it blocks the whole wave. that's why the gauss on the microwave front door works yet you can see through it, because microwaves (the actual waves) are in the order of centimetres wide.