Transparent Aluminum is real!

[kaborka]

Link. This stuff is right out of Star Trek IV (remember the whale tank?)

 

[f95toli]

Even sapphire (Al203, aluminiumoxide) is transparant (milky-white) so this is not very suprising.

 

[cheesehead]

This will be a terrific boon for aerospace and deep-sea diving. A 747's windows are more or less bulletproof and cost something like 400,000 USD each. If this stuff was used instead, the price could very likely be dropped. Deep sea divers will likely use it for windows in submersibles, and this new ceramic will very likely find itself in the space shuttle and fighter jets as well.

 

[alienal99]

how did you come up with a 747's windows being 400,000.00 each. there are close to 200 windows on a 747....that would bring the cost of windows alone to 80,000,000 (that's 80 million) dollars. considering list price on a 747 is around 218 million dollars, which would make windows about 40% of this cost....no chance in hell that that is right.

 

[xTYBALTx]

The pilot's windows you dufus.

 

[Tiamat]

Sorry to bust your bubble, but aluminum is not transparent. Alumina can be transparent and the example you provided can also be transparent. Once you react aluminum, it no longer can be considered as pure aluminum obviously...

 

[Soccerman06]

Originally posted by: Tiamat
Sorry to bust your bubble, but aluminum is not transparent. Alumina can be transparent and the example you provided can also be transparent. Once you react aluminum, it no longer can be considered as pure aluminum obviously...

So by your logic, since iron is never pure iron, once iron touches water (humidity in air you could say) it cant be considered pure iron from rust? Nothing in the world of chemistry nothing is every pure, there is always a random molecule floating around here and there. There are ways you can get most of a undesirable molecules out, but its never completely clean.

 

[DrPizza]

Originally posted by: Soccerman06

Originally posted by: Tiamat
Sorry to bust your bubble, but aluminum is not transparent. Alumina can be transparent and the example you provided can also be transparent. Once you react aluminum, it no longer can be considered as pure aluminum obviously...

So by your logic, since iron is never pure iron, once iron touches water (humidity in air you could say) it cant be considered pure iron from rust? Nothing in the world of chemistry nothing is every pure, there is always a random molecule floating around here and there. There are ways you can get most of a undesirable molecules out, but its never completely clean.

Regardless, Tiamat is correct. It's not Aluminum that's transparent. It's a compound containing aluminum.

It would be similar to me arguing that Silicon is transparent because glass is made from silicon dioxide. Or that Carbon is transparent, because carbon dioxide is transparent.

This also brings up another point: the crystal structure of the solid is one of the factors determining transparency. i.e. diamond vs. graphite

Furthermore, if you really want to get deep on the subject, "transparent to what wavelengths of electromagnetic radiation?" Some substances are transparent to visible light, but not transparent to other frequencies of light. i.e. some glass filters out UV-A or UV-B radiation. Many substances are transparent to radio frequencies or x-ray frequencies, but not transparent to visible light. Similarly, some materials are transparent to light, but not to radio frequencies. Example of the latter: Aluminum window screen. Wrap a radio or cell phone in aluminum window screen. You can see through it, but it won't receive a signal due to the wavelengths compared to the spacing of aluminum in the screen. SOoooo, going full circle, we can say that an aluminum window screen is transparent to visible light, but not to other frequencies. (it also blocks out infrared fairly well.)

 

[Soccerman06]

Originally posted by: DrPizza

Originally posted by: Soccerman06

Originally posted by: Tiamat
Sorry to bust your bubble, but aluminum is not transparent. Alumina can be transparent and the example you provided can also be transparent. Once you react aluminum, it no longer can be considered as pure aluminum obviously...

So by your logic, since iron is never pure iron, once iron touches water (humidity in air you could say) it cant be considered pure iron from rust? Nothing in the world of chemistry nothing is every pure, there is always a random molecule floating around here and there. There are ways you can get most of a undesirable molecules out, but its never completely clean.

Regardless, Tiamat is correct. It's not Aluminum that's transparent. It's a compound containing aluminum.

It would be similar to me arguing that Silicon is transparent because glass is made from silicon dioxide. Or that Carbon is transparent, because carbon dioxide is transparent.

This also brings up another point: the crystal structure of the solid is one of the factors determining transparency. i.e. diamond vs. graphite

Furthermore, if you really want to get deep on the subject, "transparent to what wavelengths of electromagnetic radiation?" Some substances are transparent to visible light, but not transparent to other frequencies of light. i.e. some glass filters out UV-A or UV-B radiation. Many substances are transparent to radio frequencies or x-ray frequencies, but not transparent to visible light. Similarly, some materials are transparent to light, but not to radio frequencies. Example of the latter: Aluminum window screen. Wrap a radio or cell phone in aluminum window screen. You can see through it, but it won't receive a signal due to the wavelengths compared to the spacing of aluminum in the screen. SOoooo, going full circle, we can say that an aluminum window screen is transparent to visible light, but not to other frequencies. (it also blocks out infrared fairly well.)

Yes true, I know, I was just making a point that nothing is pure .

 

[f95toli]

Exactly, as I wrote above sapphire (a.k.a alumina, the word sapphire is usually reserved for single crystals) is transparent.
Most oxides have properties that are very different from the metals they are made from. It is a complettely different material.

Note that there is a huge difference between an alloy (or a metal with impurities) and a chemical compound. In an alloy there are no bonds between different kind atoms and there is no definite crystal structure (steel is a good example).

 

[kaborka]

I was struck by the similarity to the "transparent aluminum" of Star Trek IV -- wasn't as concerned with chemical accuracy.

Re gemstones: Granted many of these are (close to) transparent, but what seems to be significant about this is the near-term feasibility of producing windows from the stuff.

 

[f95toli]

True, sapphire is not as transparant as glass so if this new(?) compound is really transparant it will be very useful. However, I suspect it might turn out to be difficult to use. There are pleny of complex oxides which are potentially useful but fabrication is almost always an issue.

Btw, when I write sapphire I refer to Al2O3 which is NOT a gemstone.
The name "sapphire" is of course also used for the gemstone, but then the name refers to Al2O3 with some cromium impurites, if you instead add iron impurities you get ruby.

Sapphire is a relatively common substrate used in microelectronics and you can actually buy small sapphire waffers. Sapphire has good high-frequency properties and conduct heat fairly well.
It is also often used as a substrate for the high-temperatures superconductor YBCO (which is why I use it).

 

[DrPizza]

I wonder what the index of refraction is...
This may make GREAT lens material for eyeglasses!
My #1 problem, by far, is scratches on my glasses... if sand doesn't affect this, then I'd be willing to pay a little extra for lenses.

btw, big :thumbsup: to the ceramic engineering.
Here's an example for people wondering what the heck ceramic engineering is actually about.

 

[CycloWizard]

Originally posted by: Soccerman06
So by your logic, since iron is never pure iron, once iron touches water (humidity in air you could say) it cant be considered pure iron from rust? Nothing in the world of chemistry nothing is every pure, there is always a random molecule floating around here and there. There are ways you can get most of a undesirable molecules out, but its never completely clean.

There's a difference between having a mixture of multiple species (what you describe here) and having a different species (what Tiamat was talking about). If I react something, its properties change. This has nothing to do with its purity.

 

[grant2]

Originally posted by: Cheesehead
This will be a terrific boon for aerospace and deep-sea diving. A 747's windows are more or less bulletproof and cost something like 400,000 USD each. If this stuff was used instead, the price could very likely be dropped.

Did you read the article? it said normal armoured glass is $3/square inch. This stuff is $15/square inch. That makes it 5 times as expensive currently.

Even if you're correct about the cost of the windows it's a drop in the bucket compared to the overall cost of the plane.

 

[Sunner]

Originally posted by: CycloWizard

Originally posted by: Soccerman06
So by your logic, since iron is never pure iron, once iron touches water (humidity in air you could say) it cant be considered pure iron from rust? Nothing in the world of chemistry nothing is every pure, there is always a random molecule floating around here and there. There are ways you can get most of a undesirable molecules out, but its never completely clean.

There's a difference between having a mixture of multiple species (what you describe here) and having a different species (what Tiamat was talking about). If I react something, its properties change. This has nothing to do with its purity.

Cyclo, I know you have lots of interesting information about this new compound, so spill it
Always loved your posts about this or that armor tech.

Or maybe you haven't been in touch with this work?

 

[MobiusPizza]

Originally posted by: f95toli
True, sapphire is not as transparant as glass so if this new(?) compound is really transparant it will be very useful. However, I suspect it might turn out to be difficult to use. There are pleny of complex oxides which are potentially useful but fabrication is almost always an issue.

Btw, when I write sapphire I refer to Al2O3 which is NOT a gemstone.
The name "sapphire" is of course also used for the gemstone, but then the name refers to Al2O3 with some cromium impurites, if you instead add iron impurities you get ruby.

Sapphire is a relatively common substrate used in microelectronics and you can actually buy small sapphire waffers. Sapphire has good high-frequency properties and conduct heat fairly well.
It is also often used as a substrate for the high-temperatures superconductor YBCO (which is why I use it).

The articles mentions "Aluminum Oxynitride" which is not "Aluminium (III) oxide".

 

[f95toli]

Yes, the reason why I mentioned sapphire was simply to point out that there are already several well-known aluminium compounds that are transparant (LAO is also somewhat transparant).

 

[patentman]

some glass filters out UV-A or UV-B radiation

1) Depends on what you mean by "glass." Technically anything that is has an amorphous crystal strucutre can be considered a glass;

2) Assuming you mean Silicon Dioxide based glass, pure silicon dioxide doesn't filter out UVA or UVB. Additives or impurities in do that (e.g. Iron Oxide or Cerium Oxide usually).

But your point is well taken.

 

[0roo0roo]

yay, nonscratch ipod nano!

 

[DrPizza]

Originally posted by: patentman

some glass filters out UV-A or UV-B radiation

1) Depends on what you mean by "glass." Technically anything that is has an amorphous crystal strucutre can be considered a glass;

2) Assuming you mean Silicon Dioxide based glass, pure silicon dioxide doesn't filter out UVA or UVB. Additives or impurities in do that (e.g. Iron Oxide or Cerium Oxide usually).

But your point is well taken.

By glass, I was using the term in the way most people would think of "glass" - as the clear stuff in windows, lenses, etc. Hence, in that context, "some glass filters..." made more sense. Ahhhh, the memories of a couple of classes devoted entirely to learning about glass (in ceramics engineering.)

 

[gsellis]

Please note that Lt. Cmdr. Montgomery Scott never says that Transparent Aluminum is actually Al and not a compound. Otherwise Pleathers are probably endangered now.

Beware of marketing!

 

[gsellis]

Originally posted by: f95toli
Even sapphire (Al203, aluminiumoxide) is transparant (milky-white) so this is not very suprising.

Poor ones are. Good ones are not milky (owns a clear sapphire). One I found is pink indoors and almost green in regular sunlight (called a "color change sapphire").

 

[tigertunes]

Pretty cool article

 

[f95toli]

Originally posted by: gsellis

Originally posted by: f95toli
Even sapphire (Al203, aluminiumoxide) is transparant (milky-white) so this is not very suprising.

Poor ones are. Good ones are not milky (owns a clear sapphire). One I found is pink indoors and almost green in regular sunlight (called a "color change sapphire").

The ones I use are actually single crystals (cut from a waffer) so the crystal can't really be more perfect. However, the sapphire chips we use are only polished on one side (they are 5x5x0.5 mm) so I guess the "milky white" color might be due to the rough surface.