50 yrs. of Star Trek!

[Guy Sotomayor Jr]

> On Sep 9, 2016, at 1:23 PM, Doug Ingraham <dpi at dustyoldcomputers.com> wrote:
> 
> On Fri, Sep 9, 2016 at 12:39 PM, Peter Cetinski <pete at pski.net> wrote:
> 
>> 
>>> On Sep 9, 2016, at 10:55 AM, Doug Ingraham <dpi at dustyoldcomputers.com>
>> wrote:
>>> 
>>> Transparent aluminum exists.  It is called sapphire.  Sapphire is the
>>> crystalline form of aluminum oxide.  If you recall, Apple was thinking of
>>> using it for the touch screen face of the iphone.
>>> 
>> 
>> Ah yes, but can you make in sheets 60 feet by 10 feet by 1 inch thick and
>> withstand the pressure of 18,000 cu ft of water?  :)
> 
> 
> The answer is probably yes, but not for anything like a reasonable amount
> of money or in a reasonable amount of time.  It would probably take a
> couple of years to grow a crystal that size.  There was a company making
> the ovens used to make billets of sapphire about 18 inches in diameter and
> a foot tall from which they would cut out the pieces they would need with
> presumably a diamond saw.  These billets would take something like a month
> to grow so you would need a lot of them to make your screens in the multi
> million quantities.  And these billets had imperfections you had to work
> around.  In 1986 it would probably have taken Mr Scotts technical know how.
> 
> 
Actually it actually *does* exist and is reasonable to manufacture.  Here’s the
article: http://www.nrl.navy.mil/media/news-releases/2015/transparent-armor-from-nrl-spinel-could-also-ruggedize-your-smart-phone

It’s basically a sintered process where the ceramic is formed (this particular one is called spinel)
and the process is to put the powder in a press, raise the temperature and evacuate the air.
The result is a clear crystal that has better properties than glass.  The size of the piece is only
limited by the size of the press.

TTFN - Guy