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Transparent Aluminum Is Here 625

Posted by Hemos
from the like-blue-LEDs dept.
Alien54 writes "Scientists in the US have developed a novel technique to make bulk quantities of glass from alumina for the first time. (link includes a picture of samples) Anatoly Rosenflanz and colleagues at 3M in Minnesota used a "flame-spray" technique to alloy alumina (aluminium oxide) with rare-earth metal oxides to produce strong glass with good optical properties. The method avoids many of the problems encountered in conventional glass forming and could, say the team, be extended to other oxides (see also: A Rosenflanz et al. 2004 Nature 430 761). Scotty would be pleased."
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Transparent Aluminum Is Here

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  • by inertia@yahoo.com (156602) * on Monday August 23, 2004 @09:10AM (#10044110) Homepage Journal
    Yes. It seems that he didn't pollute the time-line after all.
  • woohho (Score:5, Funny)

    by obli (650741) on Monday August 23, 2004 @09:11AM (#10044124)
    The whales will have a safe journey home!
    • Re:woohho (Score:5, Insightful)

      by inertia@yahoo.com (156602) * on Monday August 23, 2004 @09:14AM (#10044158) Homepage Journal
      What I don't get is, why did they need it to be transparent for the journey home?
      • Re:woohho (Score:5, Insightful)

        by jayhawk88 (160512) <jayhawk88@gmail.com> on Monday August 23, 2004 @09:17AM (#10044199)
        Because otherwise all that footage taken at Sea World would have been for nothing!
      • Re:woohho (Score:5, Funny)

        by dave1791 (315728) on Monday August 23, 2004 @09:18AM (#10044211)
        Do you know what happens to people who ask such questions?
      • Re:woohho (Score:5, Informative)

        by basics (702099) on Monday August 23, 2004 @09:19AM (#10044231)
        If I remember correctly, they did not need the clear aluminum but they did need something to store the whale in. Since they did not have any money they traded the formula for clear aluminum for the whale tank.
        • He traded the formula of Transparent Aluminum for sufficiently strong plexiglass for the tank.
        • Re:woohho (Score:4, Informative)

          by big_groo (237634) <groovis.gmail@com> on Monday August 23, 2004 @11:43AM (#10046267) Homepage
          You're partially correct. They needed something *light* and *strong* to compensate for the mass of the whales and water. Transparent aluminum was the only material that would satisfy those requirements. I think they said that to use steel or glass, the tank walls would have been far too thick.
          • Re:woohho (Score:4, Informative)

            by Blakey Rat (99501) on Monday August 23, 2004 @12:39PM (#10046916)
            Uh, I'm going to play Star Trek nerd here and correct you.

            Scotty and McCoy went to a plant that manufactored plexiglass because plexiglass was strong enough to hold the water and whales they needed if it were thick enough. (There's one part of the movie where Scotty calculates how thick the plexiglass needs to be to finish building their tank.) Since they had no money, they couldn't pay for the plexiglass needed so instead Scotty drew up a formula for transparent aluminum in exchange for the plexiglass. Even with the formula, it would take that plant years and years to be reconfigured to produce transparent aluminum, and they say so in the movie.

            So... yes. Grandparent is right; they traded the formula for the plexiglass.
    • Re:woohho (Score:5, Interesting)

      by GoodNicsTken (688415) on Monday August 23, 2004 @09:22AM (#10044275)
      You make that joke, but I started thinking about my reef tank as soon as I read this article. When you go over 36" tall you have to use 5/8-3/4 inch low iron (so your fish and corals are not green) glass. If this is really that much stronger, larget tanks could be made cheaper, becuase the glass could be thinner. I wonder what the optical and strength properties really are? Anyone have more information on the testing?
  • by SammysIsland (705274) on Monday August 23, 2004 @09:11AM (#10044129)
    Now I can watch as the food in the fridge turns green... Ye-hah!
  • by Anonymous Coward on Monday August 23, 2004 @09:12AM (#10044139)
    Glass breakthrough
    11 August 2004

    Scientists in the US have developed a novel technique to make bulk quantities of glass from alumina for the first time. Anatoly Rosenflanz and colleagues at 3M in Minnesota used a "flame-spray" technique to alloy alumina (aluminium oxide) with rare-earth metal oxides to produce strong glass with good optical properties. The method avoids many of the problems encountered in conventional glass forming and could, say the team, be extended to other oxides (A Rosenflanz et al. 2004 Nature 430 761).

    Glass is formed when a molten material is cooled so quickly that its constituent atoms do not have time to align themselves into an ordered lattice. However, it is difficult to make glasses from most materials because they need to be cooled -- or quenched -- at rates of up to 10 million degrees per second.

    Silica is widely used in glass-making because the quenching rates are much lower, but researchers would like to make glass from alumina as well because of its superior mechanical and optical properties. Alumina can form glass if it is alloyed with calcium or rare-earth oxides, but the required quenching rate can be as high as 1000 degrees per second, which makes it difficult to produce bulk quantities.

    Rosenflanz and colleagues started by mixing around 80 mole % of powdered alumina with various rare-earth oxide powders -- including lanthanum, gadolinium and yttrium oxides. Next, they fed the powders into a high-temperature hydrogen-oxygen flame to produce molten particles that were then quenched in water. The resulting glass beads, which were less than 140 microns across, were then heat-treated -- or sintered -- at around 1000C. This produced bulk glass samples in which nanocrystalline alumina-rich phases were dispersed throughout a glassy matrix. The new method avoids the need to apply pressures of 1 gigapascal or more, as is required in existing techniques.

    Click to enlarge
    Aluminate glasses

    The 3M scientists characterised the glasses using optical microscopy, scanning electron microscopy, X-ray diffraction and thermal analysis, and tested the strength of the materials with hardness and fracture toughness tests. They found that their samples were much harder than conventional silica-based glasses and were almost as hard as pure polycrystalline alumina.

    Moreover, over 95% of the glasses were transparent (see figure) and had attractive optical properties. For example, fully crystallized alumina-rare earth oxide ceramics showed high refractive indices if the grains were kept below a certain size.

    Author
    Belle Dumé is Science Writer at PhysicsWeb
    • Another /. dupe! (Score:5, Informative)

      by lscotte (450259) on Monday August 23, 2004 @10:53AM (#10045608)
      This news should not be surprising to anyone, since it's essentially a dupe! http://science.slashdot.org/article.pl?sid=02/02/2 0/0358206&tid=126&tid=14 [slashdot.org]

      The amusing thing, is that American scientists are given credit here, but if you look at the original article from 2+1/2 years ago, it was the Germans who discovered it. Hmmm...

      You could argue that this article is just a 'refinement' of the previous article. I could believe that only if a link had been provided to the original article. Ah well... Odd that the article itself doesn't mention previous work by the Germans either...
  • Future echoes (Score:3, Interesting)

    by Space cowboy (13680) * on Monday August 23, 2004 @09:12AM (#10044145) Journal

    I am beginning to suspect that the whole idea of sci-fi is in fact a future society time-travelling back every now and then to make a new 'Star Trek' film to nudge society onto a slightly different path :-)

    The number of Star-Trek-driven ideas that have become reality is astounding -
    • phasers. We have wireless tasers that use a laser to ionise the air then an electric current jumps towards the victim from a battery. The battery is currently an issue)
    • communicators - hell mobile phones are far better than communicators
    • voice recognition - lots available these days
    • transporters - well we've done with an entangled photon. One down, seventeen quadrillion to go. Hey, it's a start!
    • now, transparent aluminium.. someone's having a laugh!


    Ok, we're missing the big one, warp drive, but apparently we have to have a war that more or less wipes out humanity first, so I'll be happy to give it a miss in my lifetime...

    Oh yeah, FOR [insert deity]'s SAKE, STOP THE WHALING!!!

    Simon
    • by abb3w (696381) on Monday August 23, 2004 @09:16AM (#10044198) Journal
      Don't forget the Mark I Tricorder [stim.com].

    • Re:Future echoes (Score:4, Interesting)

      by dave1791 (315728) on Monday August 23, 2004 @09:27AM (#10044332)
      "Ok, we're missing the big one, warp drive,"

      OK, I am not sure how Star Trek warp drives are supposed to work, but I remember a RPC circa 1990 called Traveller 2300 had something called "stutterwarp". The idea was this, take a starship and do the transporter trick to jump a few meters, or a couple of kilometers. Now do this at a few Mhz and you have near lightspeed with very little velocity.
    • by justanyone (308934) on Monday August 23, 2004 @09:46AM (#10044548) Homepage Journal

      I like your list. But, what about the things we haven't invented yet?
      • Defensive shields (no, Mark Shields [washingtonspeakers.com] doesn't count)
      • Andorian Brandy
      • Warp drive
      • subspace communicators
      • reliable space probes
      • orbiting dry docks
      • artificial gravity
      • cheap fusion power
      • drugs that combat radiation sickness
      • a 'sterile field' for doing operations
      • funny little plasma torches they're always using
      • antimatter containment
      • Theme music that plays when something bad is about to happen
      • Doors that swish open when you walk towards them
      • Computers that play __3-D chess__ !
      • (People that play 3-D chess)
      • Food dispensers that assemble the food from component molecules as needed
      • Shuttlecraft that go into orbit without dropping any parts off during the ascent
      • Spacesuits that don't look like medieval suits of armor
      • Deflector shields that work on uncharged objects
      • Glasses (or contacts) that automatically fog up when looking at a beautiful foreign woman that you're destined to seduce and abandon

      Of course, I'm probably forgetting lots of stuff. Anyone have further things I've missed??
    • communicators - hell mobile phones are far better than communicators

      I hate to think what interstellar roaming charges are like though :)
  • Silly submitter (Score:5, Insightful)

    by gowen (141411) <gwowen@gmail.com> on Monday August 23, 2004 @09:13AM (#10044146) Homepage Journal
    who doesn't know the difference between Alumina [wikipedia.org] and Aluminum [wikipedia.org].

    What next, suggesting people use the silicon [wikipedia.org] in their computers as a breast implant [wikipedia.org]?
    • by tonywestonuk (261622) on Monday August 23, 2004 @09:19AM (#10044230)
      Isn't Aluminum a major constituant part of Alumina? (along with Oxygen)... Seams to me that that makes the term 'Transparant Aluminum' valid.
      • by gowen (141411) <gwowen@gmail.com> on Monday August 23, 2004 @09:23AM (#10044280) Homepage Journal
        Well, alumina has almost none of the same properties as aluminium (since you're from the UK too, I'll spell that word correctly from now on). It's extremely tough (used in drilling bits), non-conductive and non-reactive. One would expect something described as "Transparent Aluminium" to behave a bit like Aluminium. Alumina doesn't.
      • by sploo22 (748838) <dwahler@gmai[ ]om ['l.c' in gap]> on Monday August 23, 2004 @09:25AM (#10044310)
        Pure aluminum is a metal. Aluminum oxide is not - it's like the difference between hydrogen and water.

        As I understand it, pure metals can't be transparent because light is an electromagnetic wave which gets "short-circuited" by conductive materials. Presumably the oxides disrupt this conductivity. And anyway, the alumina is combined with other oxides before being used to form glass.
        • by dhovis (303725) on Monday August 23, 2004 @10:06AM (#10044852)
          As I understand it, pure metals can't be transparent because light is an electromagnetic wave which gets "short-circuited" by conductive materials. Presumably the oxides disrupt this conductivity. And anyway, the alumina is combined with other oxides before being used to form glass.

          Sort of....

          A better way of explaining it would be that for a photon to be absorbed by an electron, there must be an empty higher energy state for the electron to move to (E = Eo + hv, where Eo is the energy state of the electron and hv is the energy of the photon). In solids with metallic bonding, there are many electrons floating around and many free electronic states for them to move to, so any photon that enters the solid can be absorbed by an electron that will then jump to a higher energy state (which will be free, because there are so many free energy states).

          In the case of insulating and semiconducting materials, there is a gap in the energy states, so some transitions are not allowed. For pure, single crystal Al2O3, (aka white sapphire), there are (essentially) no transitions available that correspond to the energy of photons of visible light. If you start substituting in Cr3+ ions for the Al3+ ions, your sapphire will turn red and we call it "ruby". In this case, the Cr impurities provide transitions that can absorb wide ranges of visible light, but not red light. What is more is (if this is fairly pure), the ruby will not only absorb light of other wavelengths, but it will emit red light as well. Try putting a synthetic ruby under a UV light, it will glow red.

          However, it should be noted that other defects can scatter and absorb light as well. Grain boundaries, voids, inclusions, etc. will affect your light transmittance. It has been possible for some time now to make polycrystalline alumina that is translucent (Lucalox), but polycrystalline alumina can never be transparant, so there are two ways to make alumina transparant: make it single crystal (only one grain, so no grain boundaries) or amorphous (no grain boundaries, because there is no long range crystal order).

          • by Rich0 (548339) on Monday August 23, 2004 @11:28AM (#10046095) Homepage
            I remember seeing a demonstration on conductive polymers, and I immediately took notice of the fact that they had a metallic sheen to them. The same properties that lead to conduction also lead to the reflective properties of metal.

            If you just want something transparent that is very durable, you can use something like this alumina technology, or even something crazy like panes of diamond glass or something like that (I'm not sure how strong diamond glass would be, but I'm guessing pretty strong).

            On the other hand, a true transparent metal would have lots of desirable properties that none of these materials have. Metals are malleable and ductile, conduct heat well, can withstand stress by deforming, and conduct electricity. All of these properties have to do with the metallic bonds between metal atoms, and consequently they are incompatible with being transparent. That isn't to say that you can't make a nonmetallic material that can transfer heat, or which can bend - but it wouldn't be by the same mechamism as how a metal works.

            I always loved metallic bonds simply because they are such an elegant demonstration of how a microscopic property such as chemical bonding leads to macroscopic properties like conductivity and malleability.

            For those who want to know more, almost any general chemistry textbook will have a short section on metallic bonding which describes how they work and why they lead to these properties.
      • by rco3 (198978) on Monday August 23, 2004 @09:31AM (#10044373) Homepage
        No, it makes the term "transparent alumina" valid. The term 'Aluminum' refers to an element, whereas alumina refers to a compound of aluminum. If you refer to the properties of aluminum (or aluminium, if it makes this easier for you), you are (or at least will be understood by others to be) referring to the properties of a quantity of essentially pure aluminum, which is transparent under no condition.

        Therefore, the term "transparent aluminum" is incorrect. Sorry.
      • by PatrickThomson (712694) on Monday August 23, 2004 @09:35AM (#10044424)
        Yeah, and that reminds me, there's this horrific new danger-chemical being given to children, it's made from hydrogen, the most flammable gas in existence, and oxygen, the pure essense of burning, I mean the safety implications are enormous! stop DHMO now!
      • by kcelery (410487)
        As I remember, the first laser was made from a ruby rod, which is a form of aluminum oxide.
    • Why not link to... (Score:5, Informative)

      by FooAtWFU (699187) on Monday August 23, 2004 @09:24AM (#10044296) Homepage
      Why not link to the article on transparent alumina [wikipedia.org] as well? Though it needs a slight update, mind you.
  • by hal2814 (725639) on Monday August 23, 2004 @09:13AM (#10044147)
    ...but I still can't do something primitive like use my mouse to talk to the computer.
  • by nitehawk214 (222219) on Monday August 23, 2004 @09:14AM (#10044156)
    Oh who am I kidding, there are already a bunch of them by now...
  • by LucidBeast (601749) on Monday August 23, 2004 @09:14AM (#10044160)
    Aren't many jewels aluminum compounds?
    google search of rubies and aluminum:
    http://pearl1.lanl.gov/periodic/element s/13.html
    • Certainly. Sapphire is a crystal form of aluminum oxide and it is quite transparent. For example it doesn't absorb ultraviolet photons close to the visible spectrum which make it a suitable material to have in the windows to my vacuum chamber when I want to shoot UV laser light in to it.
  • by jolyonr (560227) on Monday August 23, 2004 @09:15AM (#10044168) Homepage
    Alumina (aluminium oxide) is not the same as aluminium, that's like saying that water ice(hydrogen oxide) is 'Transparent Hydrogen'.

    Alumina or corundum [mindat.org] as the natural material is known, is found in nature as a clear mineral - different colour variations give you Ruby and Sapphire.

    Jolyon
  • glassish properties (Score:3, Interesting)

    by basics (702099) on Monday August 23, 2004 @09:15AM (#10044176)
    As glass itself is technically not a solid but a slow-moving liquid would glass not made from silica have the same general properites as "normal" glass?

    I generally think of glass as being very inert for example. Anyone know if this would be the case if the glass was composed of differant substances?

    (chemistry maybe?)
  • Yes but... (Score:3, Funny)

    by condour75 (452029) on Monday August 23, 2004 @09:17AM (#10044202) Homepage
    We're so far behind on launching ubermenchen into deep space on the Botany Bay. And where's Voyager VII?
  • by Ubergrendle (531719) on Monday August 23, 2004 @09:19AM (#10044235) Journal
    One of the great things about sci-fi as a thematic backdrop (be it literature or movies/tv) is that it alone of all the genres has the possibility of inspiring a tangible effect upon the real world.

    I remember an interview with James Doohan where he said his greatest pride that came from his career was that he inspired other people to pursue careers where they could make a difference to the world. How many engineers became engineers or went into sciences because of Star Trek?

    I'm familiar with the Arthur C Clarke suggesting satellites; I doubt a similar cause/effect with Star Trek IV happened here. However, the similarities are cool, and at least with this genre there is the POSSIBILITY of changing the world for the better.

    PS Fortunately such transitions from sci-fi fantasy to real world are few and far between. 90%+ of tv SF and pulp SF is dreck, and I myself and not looking forward to a Brave New World...
    • The movie Galaxy Quest illustrated what you're talking about.

      A recent example is the Alcubierre warp drive. A general relativist took a break from computing the gravity fields of real objects to ask himself whether there was any way to create a field with the property of allowing faster-than-light travel.

      Heinlein gave another example when he testified to Congress about space program funding. He got his stroke surgery from a surgeon who excelled at having patients survive. The surgeon did so well because h
  • by evil-osm (203438) on Monday August 23, 2004 @09:20AM (#10044251)
    .. oh... joy.
  • Computer mods? (Score:4, Insightful)

    by CodeMaster (28069) on Monday August 23, 2004 @09:25AM (#10044306)
    Where are all the crazy modders?

    - Transparent aluminum case
    - Transparent hard drives
    - Transparent power supplies
    All without voiding your warranty ;-)

    And for military uses - the sky is the limit (really - think about it...)

    Get a free ipod [freeipods.com] [it really works - my buddy just got his... should have believed it earlier ;-( ]
  • Transparent ALUMINA (Score:5, Informative)

    by caffeineboy (44704) <skidmore DOT 22 AT osu DOT edu> on Monday August 23, 2004 @09:26AM (#10044314)
    Is nothing new - it's called corundum [about.com] or as you more probably know it, sapphire (or ruby when it is red).

    And hard is only one part of the story. Glass is hard, yet I wouldn't want to make structural elements of an aircraft from large hunks of glass... Aluminum is light and Tough (high energy to break). It is also ductile (deforms before breaking) something that no ceramic is...

    So, while this is cool, and will probably be used for super scratch proof layers on spyplane camera transparencies or something like that where they can afford something like this, it isn't what you think it is.

    As an aside, translucent alumina is used in something you see everyday - sodium vapor lamps use alumina to encapsulate the sodium metal that they use as their filament.
  • by MORTAR_COMBAT! (589963) on Monday August 23, 2004 @09:33AM (#10044397)
    Star Trek IV was on CBS on Saturday night. I stayed up to watch the transparent aluminum scene -- who knew the real thing was coming just 2 days later?
  • by nanimo (688603) on Monday August 23, 2004 @09:37AM (#10044440)
    "Attractive optical properties" must be nerd talk for "pretty"...
  • RTFA Editors (Score:5, Informative)

    by pertinax18 (569045) on Monday August 23, 2004 @09:42AM (#10044511) Homepage

    Transparent Aluminum Is Here

    NO IT ISN'T! Commercially developed transparent Alumina (think clear ruby/sapphire) is here, HUGE difference. Sorry Trek fans, you will have to wait longer. There will be no clear planes, no clear cases made of Alumina. If cases were transparent Alumina then they would have the same properties as silica glass and you would have a nice greenhouse effect going on slowly (or not so slowly) frying your computer.

    Alumina is a mineral/glass/ceramic, Aluminum is a metal!

  • PowerBook (Score:5, Funny)

    by "Zow" (6449) on Monday August 23, 2004 @09:45AM (#10044540) Homepage

    Somehow, I get the feeling that Apple is going to use this for the next gen of PowerBooks.

    (It's a joke -- all the materials scientists don't need to correct me.)

    -"Zow"

  • Refraction index (Score:3, Informative)

    by Florian Weimer (88405) <fw@deneb.enyo.de> on Monday August 23, 2004 @09:49AM (#10044582) Homepage
    From the article in Nature:

    Similarly, when the grain size is maintained below the scattering limit, the fully crystallized Al[2]O[3] REO ceramics exhibit attractive optical characteristics including high refractive index (1.8 and higher) and transparency through the mid-infrared range.

    Cool. Finally something to tackle the 1.8 barrier, and smaller glasses for me. 8-)
  • Transparent Alumina (Score:5, Informative)

    by dl107227 (632747) on Monday August 23, 2004 @09:53AM (#10044640)
    Sure it's been said but bears repeating.

    If you have a high quality watch it is likely that the crystal is made from polycrystalline alumina (i.e. corundum...in this case synthetic corundum). The alumina glass is different however in the fact that it is a glass and therefore lacks crystal structure.

    Since it doesn't have to be crystallized it is likely that it will be able to be produced in large sizes. However, being a glass it is not going to have the malleable properties of aluminum metal and will probably shatter if hit hard enough.
  • by anactofgod (68756) on Monday August 23, 2004 @09:59AM (#10044746)
    Now that's a headline I'd get excited about.

    I'd love a pair of sapphire-lensed sunglasses.
  • by MyDixieWrecked (548719) on Monday August 23, 2004 @10:06AM (#10044860) Homepage Journal
    I once knew a guy who had this great idea to use aluminum oxide on DVDs and CDs to prevent scratching. He said the disks could be bulletproof, scratchproof, and unbreakable, although I think he was exagerating...

    If that was the case, that would be an AWESOME application for this. Although the MP/RIAA would see that as a reason for preventing backup copies of your media. I mean, if the disk can't be damaged, why would you need a backup? Although you could still lose it or have it stolen...
    • by mikael (484) on Monday August 23, 2004 @10:28AM (#10045214)
      I once knew a guy who had this great idea to use aluminum oxide on DVDs and CDs to prevent scratching. He said the disks could be bulletproof, scratchproof, and unbreakable, although I think he was exagerating...

      I could just imagine the crime scene:

      Police Officer: Can you describe the person who attempted to raid the bank?

      Witness #1: Yes, he was covered in head to toe with CD's glued to his clothes.

      Police Officer: Can you give me any further details?

      Witness #1: I think the CD's had words on them "AOL trial account - 14 days free service".
  • by Riff6809 (780550) on Monday August 23, 2004 @10:25AM (#10045165)
    "Rosenflanz and colleagues at 3M in Minnesota" One of those colleagues wouldn't happen to be named Guildenstein, would they?
  • by peter303 (12292) on Monday August 23, 2004 @11:00AM (#10045694)
    I read some comprehensive article on "transparent concrete", probably the NY Times Sunday Magazine, but cant locate the reference. There are several related articles on Google. Concrete is seeing a resurgence as a decorative material, i.e. wall and floor coverings. Theres many ways to modify it to have more attractive decorative properties if you willing to sacrifice some structural strength. Concrete is inexpensive and easy to manipulate.

    A more accurate term is translucent concrete. One guy embeds perpendicular optical fibers so some external sunlight gets through. There are other techniques too.

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