ZERODUR® – Extremely low Expansion Glass Ceramic Applications ZERODUR® has become a performance- and quality-benchmark in many spec- tacular applications within modern tech- nology: • Stages and mirrors for lithography equipment • Mirror substrates for segmented and monolithic large astronomical tele- scopes • Ultra light weighted mirror blanks • Standards for precision measurement technology • High precision mechanical parts, e. g. ring laser gyroscope bodies • Reference standards for precision Extremely low thermal expansion expansion. At ambient temperature the measurement technology and comet ZERODUR® is an inorganic glass ceramic net thermal expansion is nearly zero, probes with 70 to 78 % of high-quartz micro- achieved with an accuracy of down to crystallites 50 to 80 nm in size, embed- 0 ± 7 ppb/K. Thanks to the careful tem- Properties ded in a remaining glassy phase. The perature processing the thermal expan- ZERODUR® is a glass ceramic with micro-crystals contract when they are sion of ZERODUR® is extremely homoge- an extremely low thermal expansion subjected to heating, whereas the glass neous. About 5 ppb/K CTE homogeneity for demanding applications in which itself expands. Size and number of the values have been achieved for 1.5 m class geometrical shape and distance micro-crystallites are carefully adjusted and 4 m class ZERODUR® blanks as well. changes must kept smallest possible to achieve an extremely low thermal under temperature variations. The key properties of ZERODUR® are: • Extremely low coefficient of thermal Properties ZERODUR® expansion (CTE) for a wide tempera- Density [g/cm3] 2.53 ture range Young’s Modulus E [GPa] 90.3 • Excellent CTE homogeneity through- Poisson’s Ratio µ 0.24 out the total volume Knoop Hardness [HK 0.1/20] 620 • Very low content of imperfections 0 ± 0.100 (class 2) • Wide range of precise geometrical 0 ± 0.050 (class 1) Coefficient of thermal expansionα shapes 0 ± 0.020 (class 0) CTE (0 °C; 50 °C) [10–6/K] • Extremely smooth surface with resi- 0 ± 0.010 (SPECIAL) dual roughness below 1 nm 0 ± 0.007 (EXTREME) TAILORED ± 0.020 ppm/K • Excellent chemical stability ZERODUR® TAILORED Optimized for application temperature profile All these properties are realized for small CTE (0 °C; 50 °C) Homogeneity < 0.01 – 0.03*10–6/K components as well as for astronomy Heat Capacity cp (20 °C) [J/(gK)] 0.80 telescope mirror blanks weighting several Thermal Conductivity λ90 °C [W/(mK)] 1.46 tons with extraordinary reproducibility. Max. Application Temperature [°C] 600 Version May 2013 Version Advanced Optics SCHOTT North America, Inc. 400 York Avenue Duryea, PA 18642 USA Phone +1 570/457-7485 Fax +1 570/457-7330 [email protected] www.us.schott.com/advanced_optics.