Technical glass ceramics picture, Zerodur
 
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ZERODUR®

Transparent glass ceramic with zero expansion

Special Properties

  • Extremely low coefficient of thermal expansion
  • Excellent material homogeneity and purity
  • High operating temperature
  • High CTE homogeneity
  • Very good chemical stability

Typical Applications

  • Ultra-precision optics
  • Mirror substrates for large astronomical telescopes
  • Substrates for X-ray telescopes
  • Ring laser gyroscope applications
  • Optical elements for comet probes
  • Flat optics and optical-flats
  • Space technology
  • Laser optics
  • Glass standards for precision measurement technology
  • Mechanical laser resonator components
  • Components and holders for fiber optics
  • Lightweight honeycomb satellite mirror mounts

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ZERODUR® glass ceramic from SCHOTT is an inorganic, non-porous, lithium aluminium silicon oxide material made by a process of controlled volume crystallization. It contains a crystallized phase and a rest glass phase which together create the unique properties of this exceptional material.

Finished block of ZERODUR® glass ceramic from SCHOTT

ZERODUR® glass block
with drilled holes

Unlike most glass materials, ZERODUR® has an ultra low coefficient of thermal expansion (CTE), which even can become zero or slightly negative at some temperatures. The expansion is even much lower than the one of quartz glass.

Another unique characteristic of ZERODUR® low-expansion glass ceramic is its exceptional good homogeneity. Even in large ZERODUR® material blocks, the fluctuations of mechanical and thermal properties are nearly not measurable. A good transparency in the range of about 400 - 2.300 nm allows a verification of the inner quality of ZERODUR®. Therefore, it can be ensured, that neither bubbles nor inclusions are undetected. Our company uses different available material-grades of ZERODUR® glass ceramic to manufacture substrates for high quality optics used for high-end applications in research, science, industry, space technology and astronomy. But also for the design of length standards, large telescope mirror projects, laser cavity systems, as well as for the design of mechanical components for fiber optics, that must not change their length when exposed to temperature changes, ZERODUR® high performance glass ceramic is an ideal material choice.

 

Our company is machining all kind of optics for a broad range of applications from these very interesting glass ceramic materials. In order to request a quotation for a finished part made of original ZERODUR® glass ceramic from SCHOTT at custom dimensions, please use the button below:

 

Request for Quotation

 

Specifications

 

Optical

Mechanical

  • Density: 2,53 g/cm3
  • Young's Modulus: 90,3 Gpa (mean value)
  • Poisson's ratio: 0,24
  • Knoop hardness : 620 ((HK 0,1/20 ; ISO 9385)

Thermal

  • Coefficient of thermal expansion (CTE):
    • Class 0 materials: 0 ± 0,02 x 10-6/K
    • Class 1 materials: 0 ± 0,05 x 10-6/K
    • Class 2 materials: 0 ± 0,10 x 10-6/K
    • Show curve of length expansion
  • Total change of length (-50 to +100 °C):
    • < 10 x 10-6/K per length of the part
  • Recommended cooling rate for applications at temperatures of 130-320 °C:
    • According to SCHOTT, small changes of the CTE might occur, if ZERODUR® glass ceramic is cooled down from between 130 - 320 °C to room temperature at a cooling rate that deviates from the cooling rate used during the production of ZERODUR®. The initial cooling rate during production is between 1°/h and 6°/h. A factor of 10 difference between the production cooling rate and the application's cooling rate may result in a permanent change of the CTE of 0,025 10-6/K.
  • Max. operating temperature:
    • 600 °C
  • Thermal conductivity:
    • 1,46 W/(m x K) (at 20 °C)
  • Thermal diffusivity index:
    • 0,72 x 10-6 m2/s (at 20 °C)
  • Heat capacity:
    • 0,80 J/(g x K) (at 20 °C)

Chemical

Hydrolytic Resistance
  • (ISO 719) HGB 1
Alkali resistance
  • (ISO under construction) Class 1.0
Acid Resistance
  • (ISO 8424) Class 1.0

Stain resistance

  • Class 0

Electrical

Electrical resistivity (at 20 °C)

  • 2,6 x 10-13 (Ohm x cm)
Dielectric Constant
  • 8,0 (1 kHz)
  • 7,4 (1 MHz)
Loss Factor tan d
  • 29 x 10-3 (1 kHz)
  • 15 x 10-3 (1 MHz)

Flatness

Surface Quality

For further detailed specifications and additional data of ZERODUR® glass ceramic, please use our information request page.

 

All given details and specifications are mean reference values and are not guaranteed. In addition, please consider our "Notes on specifications"