- Zerodur
Zerodur®is a
glass-ceramic made bySchott AG . It has both anamorphous (vitreous) component and acrystalline component. The most important properties of Zerodur are* Nearly zero thermal expansion (~0.02 x 10-6/K at 0-50°C) with outstanding 3D homogeneity
* High internal quality
* Good processing behaviour
* Can be polished to a very high accuracy
* Can be coated easily
* Low Helium permeability
* Non-porous
* Good chemical stabilityApplications
# Optics: Many optical applications such as telescopes, optical cavities etc require a substrate material with a near-zero coefficient of thermal expansion and/or excellent thermal shock resistance.
# Microlithography: Zerodur is used as a movable mechanical part in wafer stepper and scanner machines to achieve precise and reproducible wafer positioning. Zerodur is an ideal substrate material for reflective optics in the forthcoming EUV lithography due to its almost zero thermal expansion, outstanding homogeneity and good processing behavior.
# Measurement Technology: The extremely low thermal expansion and proven long-term dimensional stability of Zerodur make it an ideal reference standard for measurement instruments. [ [http://www.schott.com/optics_devices/english/products/zerodur/index.html SCHOTT AG - Schott Optik ] ]Properties
* Dispersion: (nf - nc) = 0.00967
*Density : 2.53 g/cm3 at 25°C
*Young's Modulus : 9.1 x 1010Pa
*Poisson Ratio : 0.24
*Specific heat capacity at 25°C: 0.196 cal/(g*K) = 0.82 J/(g*K)
*Coefficient of thermal expansion (20° to 300°C) : 0.05 ± 0.10 x 10-6/°C
* Maximum Temperature: 600°C [ [http://www.mellesgriot.com/products/optics/mp_3_6.htm Melles Griot Optics Guide - ZERODUR ] ]References
External links
* [http://www.schott.com SCHOTT AG - glass made of ideas ]
Wikimedia Foundation. 2010.
