Zerodur® (Schott Glass)

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Since 1947, we have been a precision machining and polishing fabricator of parts from all technical ceramics, sapphire, glass and quartz. We machine these materials to very precise tolerances (many times measured in millionths of an inch) for dimension, flatness, wedge and roundness or cylindricity. Our customers typically have a critical application that requires extremely tight tolerances in ultra-hard materials. We also have the capability to grind and polish spherical radius parts in a variety of hard materials, both inside and outside diameters, to optical requirements.

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Zerodur® is a glass ceramic with an extremely low thermal expansion coefficient.

Zerodur is a glass ceramic made by Schott Glass that is designed and formulated to exhibit essentially zero thermal expansion over a wide temperature range. This remarkable property is useful where precision parts will face wide thermal conditions in application. An ideal application is as a mirror substrate for astronomical telescopes or ring laser gyroscopes, as well as spacers for some laser assemblies.

Zerodur is an inorganic, nonporous lithium aluminum silicon oxide glass ceramic. It is transparent, but with an amber color. Precision parts are machined using a diamond grinding process and parts can then be optically polished as necessary using chemo-mechanical methods.

Insaco has many years’ experience fabricating precision parts from this material to exacting customer requirements. The material is readily available in slab form, but can be specified from Schott in large sizes weighing many tons. Since Zerodur is a proprietary material, where absolute material properties are critical to the application, it is best to contact the producer’s website directly to understand availability.

Production is a complicated process requiring melting, casting, annealing, and controlled volume crystallization. For smaller precision parts, Insaco is able to source commercial material in its best form and then fabricate it to customer requirements. We are also willing and able to fabricate from customer supplied material if preferred.

Other Glass Ceramics :
Corning ULE®

2.53 gm/cc

620 Knoop

Modulus of Elasticity

13 x 106 psi

Poisson's Ratio
Dielectric Constant
7.4 (@ 1 MHz)
Volume Resistivity

2 x 1013 ohm-cm

Coefficient of Thermal Expansion

0.00 +/- 0.1 x 10-6/°C

Thermal Conductivity
1.43 W/mK
Specific Heat
0.80 cal/g °C
Maximum Working Temperature
600 °C
Index of Refraction


Transmission Band
0.3 - 2.5 Wavelength (microns)

All properties are at room temperature unless otherwise noted.

Engineering data are representative, and are not intended as absolute nor warrantable. Manufacturer’s Data shown is blended from multiple sources and therefore illustrates the marketplace.

*Click on a Property to see a comparison of up to 10 materials