ZERODUR® Zero-Expansion Glass Ceramic

Product introduction ZERODUR? glass-ceramic is a non-porous, inorganic glass-ceramic with a completely non-directional and anisotropic structure. Due to the perfect balance between its internal glassy and crystalline states, its coefficient of thermal expansion is close to zero. Since the chemical properties and hardness of the crystalline and glassy states of ZERODUR? glass-ceramic are very similar to those of optical glass, it can be processed using the same equipment and tools used for optical glass and technical glass (such as cutting, grinding and polishing). Our advantages In terms of ZERODUR? glass-ceramic production, SCHOTT Advanced Optics has rich experience and strong capabilities, producing both tiny components and parts weighing several tons, with unique repeatable production capability. We can also supply zero-expansion glass with excellent three-dimensional homogeneity. ZERODUR? glass-ceramic has the following outstanding characteristics: Excellent internal quality Low chemical helium permeability, greatly extending component service life Can be polished to extremely high precision Good coatability Excellent processing performance Outstanding chemical stability Main applications ZERODUR? zero-expansion glass-ceramic is an ideal material for astronomy, microlithography technology, measurement technology, mechanical structures and optical systems. Supply forms ZERODUR? glass-ceramic can be supplied in the following forms: Round blanks Rectangular blocks Prism blanks Rods Cut pieces (lengths from a few centimeters to about 4 meters) In addition, we have advanced CNC processing equipment and various grinding technologies, capable of manufacturing components with complex geometries and fine structures according to customer needs. If you are interested in high-precision optical components made of this material, please click the following link or contact us. Optical processing and components Characteristics Coefficient of thermal expansion: We can provide ZERODUR? glass-ceramic materials in round blanks, square blanks or rods according to customer requirements. In the temperature range of 0° ~ 50°C, the linear coefficient of thermal expansion can be divided into the following three grades: Expansion class 2 0 ± 0.10 x 10-6 K-1 Expansion class 1 0 ± 0.05 x 10-6 K-1 Expansion class 0 0 ± 0.02 x 10-6 K-1 ZERODUR? glass-ceramic exhibits high uniformity of the linear coefficient of thermal expansion, with standard values between 0.01 x 10-6 K-1 and 0.02 x 10-6 K-1. We can also supply products with uniformity < 0.01 x 10-6 as needed. Internal quality The following data reflect the internal quality of standard ZERODUR? glass-ceramic smaller than 500 mm: Average impurity content 5/100 cm3 - Average impurity content 5/100 cm3 Maximum diameter of a single impurity 3.0 (maximum diameter of the evaluation volume 1.4) Striae (stress birefringence) < 60 nm/striae Volume stress (stress birefringence) < 6 nm/cm Other properties: - Density 2.53 g/cm3 - Thermal conductivity at 20°C 1.46 W/(m x K) - Thermal diffusivity at 20°C 0.72 x 10-6 m2/s - Heat capacity 0.8 J/(g x K) - Young's modulus at 20°C 90.3 GPa - Poisson's ratio 0.243 - Knoop hardness 0.1/20 620 Quality assurance From the entire production process to detailed and precise final inspection, we always use advanced measuring instruments to inspect the components of ZERODUR? glass-ceramic. Coefficient of thermal expansion High-precision dilatometer (referenced to PTB standards) Geometry Highly precise movable or fixed three-dimensional coordinate measuring machines Surface quality Roughness meters Internal quality Precision measuring microscopes and stress testing devices using the "de Senarmont" method Optical homogeneity: Interferometers with aperture diameters up to 500 mm

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