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Transparent Aluminium
Lynx writes "As the german magazine Spiegel reports, scientists at the Fraunhofer Institute for Ceramic Technologies have developed a transparent tile made from aluminium oxide pellets baked at 1200C. The material is very hard, and could be used as bulletproof windows." Use the fish.
Ha! That guy finally figured out those equations Scotty gave to him back in Star Trek IV! Another technological breakthough thanks to good 'ol Scotty.
Sorry. I should have read the blurb more carefully.
This isn't transparent aluminum; this is a transparent aluminum oxide. That is just not the same thing as aluminum anymore then water is Hydrogen gas, or table salt is the same thing as Sodium metal or Chlorine gas (both very harmful chemicals, sodium can explode when it comes in contact with water, and Chlorine can kill you in a few breaths, yet we eat salt all the time)
And secondly we have known about aluminum based compounds for a long time, in fact, longer then we have known about Aluminum or even about elements in general. Alum, the compound from which aluminum gets it's name (and which we extract aluminum from) has been known to man for ages and is, in fact, transparent.
autopr0n is like, down and stuff.
> this material is 3 times as strong as steal,
No, it says it is three times as _hard_ as hardened steel, which isn't the same thing (though they are related). Considering that corundum (i.e. ruby, sapphire) is made of aluminium oxide, that isn't that surprising.
Forming that hard material into tiles of unspecified but obviously reasonable toughness and strenth while keeping it transparent is the impressive bit.
rant
This material is nothing new: I covered the distinction between alumina and aluminum in this comment attached to the transparent concrete article that speculated about transparent aluminum. Bottom line is that alumina (Al2O3) and aluminum (Al) are totally different materials, so naturally they have different properties such as hardness, stiffness, transparency, etc. Alumina is what sapphires and rubies are made of. Pure alumina is clear, but the addition of color centers like chromium ions results in the color of gemstone rubies and sapphires. A search for sapphire conformal optics will show you that making windows out of sapphire for military applications is nothing new. Just about the only thing that might be new is how they make the sapphire, but the article does not provide any details about that. Yes, sapphire is cool stuff, but it's not some magical new material.
"It take 9 months to bear a child, no matter how many women you assign to the job."
P.S. Considering the number of people who are confused about the difference between silicon and silicone, it's not surprising some can't tell the difference between aluminium and alumina (aluminium oxide).
(Aluminum/aluminium is just US/international spelling. Looking at the original German article it uses "Aluminiumoxid" where the fish translation has alumina.)
rant
let out a giant yawn.
Alumina being transparent or strong is hardly new. Although the bullet proof glass thing is pretty funny. Alumina is not tough, it may be strong, and even greatly stronger than steel should we be talking about specific strength, but it is not tough at all. And I don't know about you, but the last thing I was between me and a bullet is a sheet of something that will shatter with countless sharp edges to cut me to ribbons.
I'm sure there are a great many chemical concerns that would be thrilled to tell you all about their alumina powders should you care to ask. But trust me, until we can do with alumina what clams can do with chalk the most interesting thing one is likely to do with alumina is make a crucible.
--Jimmy has fancy plans; and pants to match.
as Babelfish & Co are not really up to it yet, here's my human-made translation of the German article. I'm a German native speaker, but I can't guarantee the English spelling, so take with a grain of salt ;-).
Things in [brackets] are my remarks.
- - - -
Der Spiegel [leading German magazine, a la Times or Newsweek]
February 19, 2002
TRANSPARENT
Armour-like tile protects from projectiles
Researchers in Dresden [German city] have developed transparent and extremely hard tiles. The Pentagon, among others, is fascinated by this material, which can be used to produce e.g. bullet-proof visors.
[PICTURE] picture caption: "transparent Aluminium tile"
America's weapon technicians show interest for an armour-like tile from Dresden. At the "Fraunhofer-Institut für Keramische Technologien" [Fraunhofer institute for ceramics technologies] there, fine-grained aluminium oxide was successfully baked in an oven at 1200 C to produce an extremely hard, transparent material.
A plate sized 10x10 cm (thickness: 1 cm) only weighs about 400 g, but is three times as hard as hardened [tempered?] steel. During shooting trials on behalf of the "Bundeswehrbeschaffungsamt" [federal procurement office] in Koblenz, "outstanding results" were achieved, according to the researcher Andreas Krell.
The tiles are also being examined in the US state of Idaho: The Pentagon is fascinated by the transparency of the material, which can be used to build bullet-proof visors or big windows for armoured personnel carriers [Panzerspähwagen?].