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ZERODUR® Zero expansion glass ceramic
ZERODUR® glass ceramic is an inorganic, non-porous glass ceramic and has a completely non-directional, isotropic structure. Due to the perfect balance of glass and crystal phases within the material, the thermal expansion coefficient is nearly zero. As the crystalline and glass phases have chemical characteristics and hardness similar to those of optical glass, ZERODUR® glass ceramic can be processed using the same machines and tools as optical and technical glass (e.g. cutting, grinding and polishing). Due to its outstanding characteristics the brand LITHOTEC® describes these kind of ZERODUR® which is being used in lithographic and metrology applications.
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SCHOTT Advanced Optics has the capability and experience of manufacturing ZERODUR® glass ceramic in small components as well as in parts with weights of several tons with extraordinary reproducibility. We also offer a zero expansion material with outstanding 3D homogeneity.
ZERODUR® glass ceramic has several outstanding properties including:
- High internal quality
- Low Helium permeability provides a longer life span for the components
- Can be polished to a very high accuracy
- Can be coated easily
- Good processing behavior
- Good chemical stability
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ZERODUR® zero expansion glass ceramic is the ideal material for applications, such as astronomy, lithography, measurement technology, mechanics and optical systems.
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ZERODUR® glass ceramic can be supplied in the form of:
- Discs
- Rectangular blocks
- Prisms
- Rods
- Cut pieces measuring from a few cm up to approximately 4 m in length
Additionally, modern CNC processing equipment and a variety of grinding technologies allow the generation of complex geometries and filigree structures at the customer’s request.
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Thermal Expansion Coefficient:
Individual pieces of ZERODUR® glass ceramic (discs, plates, rods) can be supplied with a mean coefficient of linear thermal expansion in the temperature range 0° to 50°C in three expansion classes as follows:
- 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 excellent homogeneity of the linear thermal expansion coefficient. Typical values are between 0.01 and 0.02 x 10-6 K-1.
On request homogeneities < 0.01 x 10-6 are possible.
Internal Quality:
The following applies for the internal quality of “standard” ZERODUR® glass ceramic with typical dimensions < 500 mm:
- Average number of inclusions 5/100 cm3
- Maximum diameter of single inclusions 3.0 (1.4 within the critical volume)
- Striae (birefringence) < 60 nm/striae
- Bulk stress (birefringence) < 6 nm/cm
Further 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
- Thermal 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
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Modern measurement equipment is used to inspect the ZERODUR® glass ceramic parts during all stages of fabrication and at the final and most stringent inspection.
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Thermal expansion coefficient:
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Highly accurate dilatometer equipment (with reference standards provided by the PTB)
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Geometry and shape:
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Mobile and stationary 3D coordinate measurement machines with high accuracy
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Surface quality:
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Roughness measurement equipment
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Internal quality:
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Accurate measurement microscopes and stress measurement setups according to the “de Senarmont“ method
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Optical homogeneity:
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Interferometer with aperture up to 500 mm in diameter
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For further information please contact
our sales team:
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Contact
SCHOTT AG
Division
SCHOTT LITHOTEC
Otto-Schott-Str.13 07745 Jena Germany
 | +49 (0)3641/6812-201 |
 | +49 (0)3641/6812-202 |
E-mail
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