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Transparent ceramics made with aluminum

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Re: Transparent ceramics made with aluminum

#21
post #16

Other examples of "transparent aluminum": ruby and sapphire, both of them varieties of the mineral corundum, or Al2O3.

Slashdot, 2004:

https://slashdot.org/story/04/08/23/1141217/transparent-alum...

tl;dr: Transparent alumin_a_, not transparent alumin_um_.

Re: Transparent ceramics made with aluminum

#22
post #12
post #10

Earlier quoted context omitted.

I don't think in quite understand. You mean they don't let photons to pass through? In which case do electrons in orbit? Or nuclei for example? Or does this need advanced physics knowledge?

Roughly light is electromagnetic radiation and puts force on electrons it comes in contact with. If the electrons are fixed in a non conductor they don't move much and so don't absorb the energy. If they can move as in most metals the force accelerates them and they absorb energy from the radiation, stoping of reducing it.

What about partial ? or only to some wavelengths ?

Re: Transparent ceramics made with aluminum

#24
The deal is that it isn’t aluminium. Seriusly, what’s with the clickbate headline? If you consider everything that contains aluminium atoms in the structure to be actual aluminium, then Saffire is also transparent aluminium.

The authors are diliberatly misleading their readers in order to cincrease interest. That’s a shitty thing to do in science even if do have a cool materiale on It’s own merits.

Re: Transparent ceramics made with aluminum

#25
post #12

Earlier quoted context omitted.

Roughly light is electromagnetic radiation and puts force on electrons it comes in contact with. If the electrons are fixed in a non conductor they don't move much and so don't absorb the energy. If they can move as in most metals the force accelerates them and they absorb energy from the radiation, stoping of reducing it.

What about partial ? or only to some wavelengths ?

X-rays penetrate metal to some extent, though they also scatter off the atoms. Radiography of high value/risk metal components (such as the stressed parts of gas turbine engines) is a mainstream non-destructive testing technique.

Re: Transparent ceramics made with aluminum

#26

The deal is that it isn’t aluminium. Seriusly, what’s with the clickbate headline? If you consider everything that contains aluminium atoms in the structure to be actual aluminium, then Saffire is also transparent aluminium. The authors are diliberatly misleading their readers in order to cincrease interest. That’s a shitty thing to do in science even if do have a cool materiale on It’s own merits.

The headline relates to a line in an old movie (which is mentioned in TFA At the bottom of the page).

Re: Transparent ceramics made with aluminum

#27
post #8

This definitely looks like something that has the potential to be really useful, and gives the example of replacing gorilla glass. While I get that this is a very tough glass, I did not see anything about it's hardness in relation to gorilla glass, as hardness is the property that provides the scratch resistance that is so highly sought after in smartphone screens. Toughness is how much energy a material can absorb,…

According to wikipedia's AlON page it has a knoop hardness of ~1800 which from my understanding of things (I may have misread sources or be mistaken, I'm not a material scientist or even amateur) looks to be about equivalent to sapphire glass and much higher than gorilla glass (~600). edit: in fact while I skipped the intro it states specifically that AlON has ~85% the hardness of sapphire, which more or less checks…

I believe hardness is actually a bad thing in terms of replacing gorilla glass in phones. It increases the likelihood of shattering when dropped, and is the main reason for sapphire not being adopted.

Re: Transparent ceramics made with aluminum

#28
post #27
post #8

Earlier quoted context omitted.

According to wikipedia's AlON page it has a knoop hardness of ~1800 which from my understanding of things (I may have misread sources or be mistaken, I'm not a material scientist or even amateur) looks to be about equivalent to sapphire glass and much higher than gorilla glass (~600). edit: in fact while I skipped the intro it states specifically that AlON has ~85% the hardness of sapphire, which more or less checks…

I believe hardness is actually a bad thing in terms of replacing gorilla glass in phones. It increases the likelihood of shattering when dropped, and is the main reason for sapphire not being adopted.

> It increases the likelihood of shattering when dropped

AlON seems significantly tougher than glass as well as being way harder. So it looks to be both more scratch-resistant and more shatter-resistant.

> is the main reason for sapphire not being adopted.

Do you have sources (actual sources, not Corning fearing for their business) for that?

Re: Transparent ceramics made with aluminum

#29
post #27
post #8

Earlier quoted context omitted.

According to wikipedia's AlON page it has a knoop hardness of ~1800 which from my understanding of things (I may have misread sources or be mistaken, I'm not a material scientist or even amateur) looks to be about equivalent to sapphire glass and much higher than gorilla glass (~600). edit: in fact while I skipped the intro it states specifically that AlON has ~85% the hardness of sapphire, which more or less checks…

I believe hardness is actually a bad thing in terms of replacing gorilla glass in phones. It increases the likelihood of shattering when dropped, and is the main reason for sapphire not being adopted.

"main reason for sapphire not being adopted"

Edmund Optics sells a sapphire window thats unfortunately round, too thin (2mm) and too small (75 mm about 3 inches) to replace the glass in an iphone; the primary problem is that far too small optical window costs $650. On one hand a sheet large enough for a phone would cost more, on the other hand industrial production would be cheaper, much handwaving and it could be done but it'll cost $1K per phone, perhaps.

Re: Transparent ceramics made with aluminum

#30
post #29
post #27

Earlier quoted context omitted.

I believe hardness is actually a bad thing in terms of replacing gorilla glass in phones. It increases the likelihood of shattering when dropped, and is the main reason for sapphire not being adopted.

"main reason for sapphire not being adopted" Edmund Optics sells a sapphire window thats unfortunately round, too thin (2mm) and too small (75 mm about 3 inches) to replace the glass in an iphone; the primary problem is that far too small optical window costs $650. On one hand a sheet large enough for a phone would cost more, on the other hand industrial production would be cheaper, much handwaving and it could be do…

There have been phone screens made of sapphire, e.g. there was a special edition sapphire version of the HTC U Ultra (https://www.theverge.com/circuitbreaker/2017/5/4/15544426/ht...) which cost 150 Euro more than the glass version. I guess for just screen protection you don't need as high quality as for optical applications.
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