Re: transparent aluminum

From: Doug Jones (
Date: Mon Feb 25 2002 - 00:21:01 MST

justin corwin wrote:
> This small item details the apparent manufacture of small quantities
> of "tranparent aluminum"
> it's listed as a weapon's technology, but i have to wonder, is this kind
> of thing useful as a spacecraft material? and baking extremely finegrained
> aluminum into transparency kind of implies this can be done to other
> metals. titanium windows, anyone?

I get really exasperated with sloppy terminology and incompetent
reporting. It's transLUCENT aluminA, not transparent aluminum, dammit.
It's simply sintered aluminum oxide with particles significantly less
than 500 nm, so that it scatters visible wavelengths poorly. If you
want it actually transparent, hell, just use crystalline alumina- better
known as sapphire. 'Taint cheap, though. The sintered material is
probably tougher than sapphire, but still very brittle. Glass makes
lousy armor.

Metals are inherently opaque precisely because they are electrically
conductive- once you get more than a few skin depths of material, the EM
field gets attenuated away to nothing. Transparent aluminum or any
other metal is physically impossible. It ain't often that I can state
something with such confidence.

While I'm being cranky, I also dislike cutsie writing without capital
letters. e. e. cummings was clever and innovative, anyone else is
either too damn lazy to punctuate, or is trying waaay too hard to be
"artistic". It's childish and derivative.

Doug Jones, Rocket Plumber
Tilting at windmills again

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