Ceramic ZERODUR® K20

Product Information Small thermal expansion for high-temperature applications ZERODUR® K20 has been optimized to withstand higher application temperatures than ZERODUR®. The material is white in color and offers good infrared (IR) transmittance between 3.5 and 5 μm and homogeneous high reflectivity properties. The non-porous ZERODUR® K20 exhibits good polishing abilities, excellent vacuum properties and can be delivered as small, high-precision optical components. Advantages • Optical high long-term temperature stability up to 850 °C at compared to glases with low CTE of 2 x 10-6 • Can be matched with low thermal expansion metal alloys (e.g. Invar®) • Excellent homogeneity and internal quality • A remission of more than 90% in the visible range with a matte brilliant white finish • Free of pores and polishable to low surface roughness levels • Large-scale parts can be produced with dimensions up to 1.5 m Technical Details Properties ZERODUR® K20 Expansion coefficient α (20 - 700 °C) [10-6/K] : 2.4 Expansion coefficient α (20 - 300 °C) [10-6/K] : 2.2 Expansion coefficient α (0 - 50 °C) [10-6/K] : 1.6 Density p [g/cm3] : 2.53 Young’s modulus E [GPa] : 84.7 Heat Capacity cp at 20 °C [J/(gK : 0.90 (extrapolated) Thermal conductivity at 20 °C [W/(mK : 1.63 Max. application temperature [°C] : 850 Quality Assurance State-of-the-art measurement equipment is used to inspect ZERODUR® K20 glass ceramic parts during the entire manufacturing process.