The Wonders of Transparent Aluminum

AlON Dome

Those of you, um, enthusiastic enough to remember Star Trek IV may recall the scene embedded here. If not, let me set up the clip: The crew of the Enterprise has gone into the past to retrieve some whales, OK? And take them “back to the future,” to coin a phrase. But Scotty has a problem: He needs stuff to build a giant whale tank on the ship, but he has no goods to trade with, because, you know, in the future they only work to better themselves and nobody but a Ferengi would stoop to carrying money around. So Scotty barters his knowledge of 23rd century materials technology with a 20th century engineer, who agrees to make him what he needs in exchange.

The 23rd century material in question is “transparent aluminum,” and today I’m here to tell you: That future has arrived. Sort of. Pretty much.

The scene, as written, seems to imply that Scotty is talking about some fancy way of making metallic aluminum into a transparent form. Which ain’t happening. What has happened, however, (and in fact what was happening in research circles at least as far back as 1981) is the development of a transparent aluminum-based ceramic called aluminum oxynitride, aka “AlON,” that sounds a heckuva lot like the stuff Scotty is peddling. In fact, Star Trek IV came out in 1986, and it’s entirely likely that one of the film’s six (!) credited writers got wind of transparent aluminum from then-ongoing publicity about AlON, and decided to use it in the script.

Transparent aluminum starts out as a pile of white aluminum oxynitride powder. That powder gets packed into a rubber mold in the rough shape of the desired part, and subjected to a procedure called isostatic pressing, in which the mold is compressed in a tank of hydraulic fluid to 15,000 psi, which mashes the AlON into a grainy “green body.” The grainy structure is then fused together by heating at 2000 °C for several days. The surface of the resulting part is cloudy, and has to be mechanically polished to make it optically clear.

All that work pays off. AlON can do amazing things. Here, for instance, a 1.6″ thick AlON plate successfully resists a huge, powerful .50 AP bullet that smashes easily through more than twice that thickness of conventional laminated glass armor, with plenty of energy left over to extremely kill a plastic mannequin head.

It’s expensive, of course, and so generally reserved for high-performance applications, especially in military fields. AlON is manufactured by Massachusetts-based Surmet Corporation for use in armored windows, lenses for battlefield optics, and “seeker domes,” which are the clear round windows covering the sensor heads on the business ends of many missiles. If you want to read further, Tom Scheve has prepared a good bibliography over at HowStuffWorks.

140 thoughts on “The Wonders of Transparent Aluminum

  1. I still like picking up my mouse from time to time, and saying, “hello, computer,” into it. When no one’s watching, of course.
    Cool beans, about the ALON process. Thanks for that.

  2. My question is a sheet of AION in the dimensions listed in the movie able to handle the force of that much water?

    1. Transparent aluminum was not used to make the whale tank, that was good old plexiglass. Scotty ‘paid’ for the plexiglass with the formula for TA.

      1. but scotty said that a piece transparent aluminum at 60 feet by 10 feet by 1 inch could hold back 18,000 cubic feet of water
        Ah, what else indeed? Let me put it
        another way: how thick would a piece
        of your plexiglass need to be at 60
        feet by 10 feet to withstand the
        pressure of 18,000 cubic feet of

        That’s easy: 6 inches. We carry
        stuff that big in stock.

        Yes, I noticed. Now suppose — just
        suppose — I could show you a way to
        manufacture a wall that would do the
        same job but was only an inch thick.
        would that be worth something to
        you, eh?

  3. sorry to be “that guy” but it wasn’t the Enterprise that went back in time but a Klingon warship.

      1. Though I appreciate your leaping to my defense, in fact it originally said “the Enterprise,” and I later corrected it to “the crew of the Enterprise.”

        Now that I think about it, this distinction was a crucial plot point: As I recall, it was significant that they went back in a Klingon ship because they had to be able to hide the ship from 20th century Earth dwellers using a cloaking device. And the Federation doesn’t use cloaking technology. I think. I may be digging myself a hole, here… =]

        1. Actually, the Defiant could cloak…

          The Defiant is the first Starfleet ship to legally carry a cloaking device. Supplied by the Romulan Star Empire, the cloak is initially operated by a Romulan officer serving aboard the Defiant. An agreement between Starfleet and the Romulans limits the use of the cloak to intelligence-gathering missions in the Gamma Quadrant in exchange for all of Starfleet’s intelligence on the Dominion. However, on several occasions, such as the rescue of the Detapa Council (DS9: “The Way of the Warrior”), the cloaking device was used illegally in the Alpha Quadrant.

        2. Also, was the Defiant’s cloak the side effect of the Federation’s research into phase shifting tech? I’m not the ‘ginormous geek’ that some of y’all are, but I seem to remember that part of the reason for the Romulan/Federation Cloak treaty was in part the Defiant herself, and that the fact that the cloak effect also made the ship out of phase, and thus, both immune to damage and able to pass through regular matter. Something to do with Reicher’s alternate self going on a rampage…and the issue with Defiant’s being 100 years later has no functional bearing, since we’re discussing Time Travel, in the first place…

          1. No, Defiant came later too. The treaty was something like 70-80 years old at that point. The one Riker was involved in was the USS Pegasus, which did have a phase cloak. The Defiant was allowed by the Romulans to confront to possible threat of the Dominion. (Yes, I know, I have no life)

      2. @Jake: Note, however, that the Defiant postdates Star Trek IV’s initial timeline (time travel notwithstanding) by approximately 100 years (ST IV set in 2386, U.S.S. Defiant launched in 2370).

        Why yes, I am a ginormous geek. ;)

        1. 2286. Not 2386. I’m trying to work out how you could have thought DS9 was before the launch of the Enterprise A…

          1. LOL I love this discussion. The reason they were in a Klingon Bird of Prey was not that they needed to be able to cloak. it was because the Enterprise was destroyed at the end of Star Trek iii and they took over the Klingon ship. They were on their way home to face the consequences when the Probe came to earth to talk to the whales. As far as the Cloaking device goes. Its not that the federation didn’t have the tech. they stole it in ” the enterprise incident” (Kirk as a Romulan was priceless) episode of the original series. its that they signed an agreement with the Romulans that they would not install it in any federation star ships.

  4. Al2O3 has (clear) sapphire as one of its forms. (The gemstone colors come from impurities.) Pricier to manufacture, but it has some interesting properties as well. Not only clear to the normal visual range, it’s also transparent in the ultraviolet and the vacuum ultraviolet. It doesn’t start start melting until something like 2000C. (I’d give the exact number, but Wikipedia is protesting the insane SOPA thing today.)

    I don’t know about its properties with regards to bullets, but it’s a pretty tough single-crystal type of material. Holding the ‘whale tank’ in something less than an inch-thick plate sounds eminently plausible.

    It also just will -not- burn and is quite chemically inert. You’re at the bottom of the amazing thermite reaction – the oxygens really like being with the aluminum.

    1. sounds like a good window for the Space shuttle….
      oh ya they retired it…
      good window for a space station?

  5. I had seen a similar article on a site that I think used to be called “Sci-Fighter” and it was back in 2001/2002 describing a very similar process that the Germans were using, but as I recall, their results had an orange cast to them instead of being optically clear.

    Cool stuff!

  6. That’s so funny. I have a wireless mouse so I can walk around the house and still give orders to my computer. Man, the old days were so quaint!

  7. As for the transparent aluminum mentioned in StarTrek, it has been around for a long time and was used as a bullet shield at Obama’s Inaguration.

    Another use is as a chrystal on rolex watches.

    1. i dont know much about the glass but i konw for sure his little podium was a ton of kevlar. My Friend in stagehands union built it.

  8. Star Trek was always coming up with stuff that, like Jules Verne, was eerily prophetic. Remember the Shatner days and the computer library chips that were little squares? And know we have thumb drives. The formula for the probability of life sustaining planets in the cosmos? Nobody ever challenged it as total bunk, and was a total guess but remarkably close to what Carl Sagan later came up with.

    The sets were designed by set designers with no outside input, but when NASA scientists and techs toured behind the scenes of Star Trek, the constantly remarked how similar many of the set’s features were like stuff NASA had or was developing.

    And there is a natural “transparent” aluminum… Saphire. So it’s maybe not much of a stretch to a sci-fi writer that a thick, clear, tough, transparent aluminum might be possible.

    1. If you read the article, the aluminum oxynitride was around 5 years before the movie was made. Also much of the “prophetic” stuff in star trek was in scifi novels and stories years before.

    2. …and cell phones!!
      I would have to ask Shatner if he was calling “Spock” If I could stop laughing!
      “Why…Yes… I……………………am.”
      loved them all, (actually met James Doohan!)

    1. Wow. Can’t believe it took a month for anyone to point this out!! thanks Craig. Maybe star trek’s graphic designers were great, but their engineering was not! (OK, i’m totally trolling with that last sentence).

    2. Scotty gave partial dimensions (in feet) so I imagine the guy just did the math in his head to calculate the lateral pressure at the bottom of the column. Remember, there are two types of people in the world: those who can extrapolate from incomplete data

  9. Of course if HAD to be transparent. Otherwise they could have used any plate metal out of a scrap yard.

    1. LOL. How else could they have there own whale tank and to bev able to watch the wales

  10. I never really understood why it HAD to be transparent…i mean they weren’t constructing a permanent Sea World exhibit that would house George & Gracie (the whales’ names) for years. I suppose it’s more humane but for that amount of trouble?

    Anyway, does this new substance block cellular signals as bad as aluminum? If so we may want to keep our gorilla glass for a while.

  11. Nice, probably crazy expensive though.

    I never quite understood why no-one makes copper sheet, grown via electroplating with embedded optical fibres?
    Would make for nice outdoor sculptures with an LED embedded within the grown copper which acts as a nice little heatsink.

    I’ve seen transparent concrete demoed before, essentially the same idea.
    Just my $0.02 worth.

  12. I love that line: “A keyboard, how quaint!” I realize I’ve been misquoting it, saying “Ach! How primative!” …but may way DOES sound better with a Scottish accent!

  13. It would be interesting to compare the matrix materials of the dome structures in ruin found on the Moon & Mars with this formula . We definitely need domes for infrastructure that on earth or any planet can sink beneath the earth during a solar event or other catastrophe.

  14. we’ve manufactured transparent aluminium for years, … its called industrial Sapphire and is used to make lenses, watch crystal faces and so forth

    1. Yes, and no. Yes, sapphire is a transparent aluminum compound. And no, this is not sapphire.

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  16. I could have sworn that “transparent aluminum” was mentioned in Star Trek before 1986… I’m sure the role-playing game from FASA mentioned it, and that was first published in 1982. I just can’t put my finger on WHERE it may have first appeared.

    1. Ah, someone claims that transparent aluminum first appeared in the original 1978 Battlestar Galactica, so that pushes it back a little bit…

  17. It also just will -not- burn and is quite chemically inert. You’re at the bottom of the amazing thermite reaction – the oxygens really like being with the aluminum.

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  19. ACTUALLY, blah blah blah blah blah Star Trek, blah blah blah blah Klingon…Star Fleet blah blah blah blah.

    Case in point: blah blah blah blah and you can’t say that blah blah blah happened because blah blah didn’t even exist until blah blah blah.

    That’s what I don’t get about blah blah blah, always screwing up the details and blah blah blah cuz it’s the details that count blah blah blah Star Trek.

  20. I’m courious, can the AlON also be made leaded to provide ‘some’ protection from solar radiation in space? A book I am writing relies on leaded acrylic to do the job.

  21. you earthlings are quite amusing and lively. we all love you– vicariously from a distance of course. maybe we can get together after your great mutation when you get out of the rut.
    clue: gravity is acceleration. best, galactic center.

  22. Too bad the “Reboot” of Star Trek has made ALL of the old mythology obsolete and part of an alternate universe we’ll never EVER see again. Voyage, DS9, TNG – all can’t happen now because someone has an ego that just HAD to be bigger than Rodenberry’s.

    Sad, how they were allowed to destroy the show…

    1. Right… destroyed… Men in black SUV’s even came to my house and confiscated my old… oh wait… never mind.

      As for the alternate reality issue, this isn’t the first time. The writers have rewritten trek history many times, and each time it’s a travesty, a horror, death to Star Trek… until the next time it happens. It would be wonderful if us trek fans weren’t such drama queens.

    2. As I’ve tried to tell some friends on this topic. It isn’t gone, it’s just….still over there :) Though, I do agree with you about a certain director’s ego. Just like the transformers movies….seen all of them…have YET to see a single Transformer!

  23. Sean,

    What a pity,that you are not enthusiastic enough about Star Trek,to realize that this story took place in the 23rd century,not the 24th century.

  24. would have been nice for some one yet to post how to make white aluminum oxynitride powder included

    1. oxynitride sounds like oxygen and nitrogen are involved, if you have ever seen white powder forming on aluminum, that is aluminum oxide, so im guessing they take that and add nitrogen to it somehow
      its just a guess, i only went to school to eat my lunch

      1. or take a NO of some configuration and mix that with Aluminum powder…

        I want to know how to fix this stuff if/when it gets damaged. We could use it on the moon or for space shuttles and stations or subs… Lot of scientific applications

    1. There’s even a mesh screen that lets air through but not water.
      Screen door on a submarine!

  25. Yet another tech partly influenced (knowledge about it) by Star Trek, although it was already experimented years before the ST IV, I would have never dreamed that something like this could even exist in our time, Or can it? Sean, you just gained a follower,…good stuff man.

  26. Predicted in a Star Trek movie? Nonsense! Everyone knows this technology was provided by the Roswell Aliens who are still in captivity in Studio 54 (they are disco maniacs!)

  27. so, its prohibitively expensive NOW… But in the future is its price come down enough that I can have a motorcycle helmet made of the stuff?

  28. Transparent aluminum in Star Trek predates the fourth movie and might predate the movies themselves. I remember reading it in novels and tech manuals long before it showed up in STIV, it wasn’t first introduced there.

    1. Nope. Look at your periodic table. The symbol for aluminum is upper-case-A-lower-case-l. Sorry if it’s typographically inconvenient for you. Don’t take your serif issues out on me.

  29. This article is poorly written. Pity the author can’t be more ‘enthusiastic’ about ‘enthusiastic’ things on a ‘enthusiastic’ online magazine.

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I am descended from 5,000 generations of tool-using primates. Also, I went to college and stuff. I am a long-time contributor to MAKE magazine and My work has also appeared in ReadyMade, c't – Magazin für Computertechnik, and The Wall Street Journal.

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