Zerodur (notation of the manufacturer: ZERODUR®), a registered trademark of Schott AG, is a lithium aluminosilicate glass-ceramic produced by Schott AG since 1968. It has been used for a number of very large telescope mirrors including Keck I, Keck II, and SOFIA. With its very low coefficient of thermal expansion it can be used to produce mirrors which retain acceptable figures in extremely cold environments such as deep space. Although it has advantages for applications requiring a coefficient of thermal expansion less than that of borosilicate glass it remains very expensive as compared to borosilicate. The tight tolerance on allows for highly accurate applications which require high-precision.
Zerodur has both an amorphous (vitreous) component and a crystalline component. Its most important properties are:
Bless my soul
Herc was on a roll
Person of the week in every Greek opinion poll
What a pro
Herc could stop a show
Point him at a monster and you're talking SRO
He was a no one
A zero, zero
Now he's a honcho
He's a hero
Here was a kid with his act down pat
From zero to hero in no time flat
Zero to hero just like that
When he smiled
The girls went wild with
Oohs and aahs
And they slapped his face
On ev'ry vase
(On ev'ry "vahse")
From appearance fees and royalties
Our Herc had cash to burn
Now nouveau riche and famous
He could tell you
What's a Grecian urn?
Say amen
There he goes again
Sweet and undefeated
And an awesome 10 for 10
Folks lined up
Just to watch him flex
And this perfect package
Packed a pair of pretty pecs
Hercie, he comes
He sees, he conquers
Honey, the crowds were
Going bonkers
He showed the moxie brains, and spunk
From zero to hero a major hunk
Zero to hero and who'da thunk
Who put the glad in gladiator?
Hercules!
Whose daring deeds are great theater?
Hercules
Is he bold?
No one braver
Is he sweet
Our fav'rite flavor
Hercules, Hercules ...
Bless my soul
Herc was on a roll
Undefeated
Riding high
And the nicest guy
Not conceited
He was a nothin'
A zero, zero
Now he's a honcho
He's a hero
He hit the heights at breackneck speed
From zero to hero
Herc is a hero
Now he's a hero
Yes indeed!