Zerodur
ZERODUR® uniquely combines the properties of glass and ceramics, making it ideal for high-precision applications in research and development.
Developed by Schott AG in 1956, it has since proven itself in use under extreme conditions, such as those prevalent in astronomy.
The glass-ceramic material is produced under controlled volume crystallization and the resulting residual glass and crystalline phase determine the exceptional material behaviour.
ZERODUR® is characterized by good material homogeneity, chemical resistance and long-term stability.
A special feature is its zero expansion in the event of temperature fluctuations, resulting in hardly any fluctuating mechanical properties.
These special features make ZERODUR® ideal as a substrate material for optical elements in comet probes, as a mirror substrate for large astronomical telescopes and other applications in precision optics and measurement technology.
Optical properties | |
|---|---|
Refractive index | nd= 1.5424 @587.6 nm |
Abbe number | νd= 56.1 |
Optimum transmission spectrum | 400-1250 nm |
Transmittance @ 580 nm | |
5 mm thickness | 0,95
|
10 mm thickness |
0,90 |
Voltage optical coefficient K @ 589.3 nm | 3.0*10-6 MPa-1 |
Physical properties | |
|---|---|
Thermal expansion coefficient in 1/K | 0,1-0,02*10-6 |
Density in g/cm3 | 2,53 |
Index of thermal diffusivity a at 20 °C in m2/s | 0,72*10-6 |
Heat capacity cp at 20 °C in J/(g – K) | 0,80 |
Modulus of elasticity E at 20 °C in GPa | 90,3 |
Poisson’s ratio | 0,24 |
Knoop hardness HK 0.1/20 (ISO9385) | 620 |
Electrical resistance ρ at 20 °C [Ω – cm] | 2,6 – 1013 |
Tk100 [°C], temperature for ρ = 108 [Ω – cm] | 178 |
Maximum processing temperature | 600 °C |
