ZERODUR
also Schott ZERODUR, Astronomical Mirror Glass
ZERODUR is a lithium-aluminosilicate glass-ceramic whose crystalline and glassy phases are balanced during ceramization to give a near-zero coefficient of thermal expansion, with an elastic modulus of 90.3 GPa and service to 500 °C.
Reference datasheet — ZERODUR is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the Annealed Glass condition
ZERODUR tempers and conditions
ZERODUR is supplied in 6 conditions, soft to hard. Annealed Glass is the default FabDigit quotes; the values on this page are for it.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed GlassDefault standard ceramized & fine-annealed ZERODUR, Expansion Class 2 | Default commercial delivery state: ceramized, fine-annealed blank with CTE 0 ± 0.10 ×10⁻⁶/K — use for general precision optics and mechanical metrology parts. | 30 | 620 HV | 1 W/m·K | ||
Expansion Class 1 | Tighter-CTE selection for telescope mirror blanks and stable structures where thermal drift budget is a few nanometres. | 30 | 620 HV | 1 W/m·K | ||
Expansion Class 0 | Premium selected class for EUV lithography optics, ring-laser gyros and length standards; long ceramization/selection cycle raises price and lead time. | 30 | 620 HV | 1 W/m·K | ||
Expansion Class 0 EXTREME | Highest-specification tolerance class, reserved for EUV mask blanks and ultra-stable metrology where CTE must be near-perfectly zero. | 30 | 620 HV | 1 W/m·K | ||
Thermomechanically controlled processed | Shorter ceramization route giving lower cost and shorter lead time at somewhat wider CTE tolerance — for large mirror substrates and mounts. | 30 | 0 | 620 HV | 1 W/m·K | |
ZERODUR K20 | Companion glass-ceramic with a deliberate small positive CTE, chosen to CTE-match metals/coatings or as a lower-cost mechanically similar substrate. | 30 | 620 HV | 2 W/m·K |
What is ZERODUR?
ZERODUR is a lithium-aluminosilicate glass-ceramic whose crystalline and glassy phases are balanced during ceramization to give a near-zero coefficient of thermal expansion, with an elastic modulus of 90.3 GPa and service to 500 °C. It is chosen for optical and metrology structures that must hold figure through temperature swings, supplied as cast blanks, plates and lightweighted mirror substrates in expansion classes from annealed through EC1, EC0 and EC0-EXTREME. It cannot be welded, hot-formed or thermally toughened, and is shaped only by diamond processes. Fused silica is the usual lower-cost alternative when CTE tolerance is looser. ZERODUR has a density of 2.53 g/cm³ (0.0914 lb/in³), lighter than 66% of glass grades. ZERODUR has a tensile strength of 30 MPa (4.35 ksi), weaker than 80% of glass grades. The elastic modulus is 90.3 GPa (13.1 Msi).
What is ZERODUR used for?
- Telescope mirror blanks
- Astronomical optics
- Lightweighted honeycomb mirror substrates
- Metrology reference plates and straightedges
- Ring laser gyroscope bodies
- Lithography stages and mask blanks
- Interferometer base structures
Advantages
- Tough — resists crack growth — 0.9 MPa·√m (0.819 ksi·√in), better than 79% of glass grades
- Stiff — 90.3 GPa (13.1 Msi), better than 75% of glass grades
ZERODUR properties
Typical room-temperature values for ZERODUR-Annealed Glass; bars are the position among glass grades.
Physical4
ZERODUR has a density of 2.53 g/cm³ (0.0914 lb/in³), lighter than 66% of glass grades.
Mechanical11
ZERODUR has a tensile strength of 30 MPa (4.35 ksi), weaker than 80% of glass grades. The elastic modulus is 90.3 GPa (13.1 Msi).
Thermal5
ZERODUR is rated for continuous service to 500°C (932 °F). It conducts heat at 1.5 W/m·K (0.844 BTU/hr·ft·°F), better than 59% of glass grades. Thermal expansion is 0 µm/m·K (0 µin/in·°F).
Electrical5
ZERODUR is an electrical insulator with a dielectric strength of 20 kV/mm (508 V/mil) and a resistivity of 1×10¹² Ω·m.
Chemical & Environmental2
Corrosion resistance is excellent (85/100), better than 65% of glass grades.
Sustainability4
Producing a kilogram of ZERODUR takes about 90 MJ of energy and emits 6.5 kg of CO₂ — more than 66% of glass grades. Typical recycled content is 0%.
Manufacturability3
ZERODUR's machinability is poor (20/100, better than 56% of glass grades).
Common Calculations3
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the glass family
Yield strength against density for every glass grade FabDigit runs. ZERODUR is highlighted; hover a dot for its name, or open the interactive family chart.
Working with ZERODUR
Is ZERODUR easy to machine?
Diamond grinding, core drilling, lapping and ultrasonic machining only — no conventional cutting; keep coolant flooded and avoid edge chipping, then acid-etch or fine-grind to remove subsurface damage.
Can ZERODUR be welded?
Not weldable; parts are joined by optical contacting, low-stress epoxy/silicate bonding, frit bonding or Invar/steel flexure mounts.
Can ZERODUR be formed, bent or molded?
Supplied as cast, ceramized blanks; near-net shapes (lightweighted honeycomb mirrors) are produced by machining the blank, not by hot forming, since re-heating above ~600 °C alters the crystal phase and CTE.
ZERODUR chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| SiO2network former | 54 – 58 | 55.5 |
| Al2O3 | 24 – 26 | 25.3 |
| P2O5 | 6.5 – 8.5 | 7.5 |
| Li2Oforms high-quartz solid solution crystals | 3 – 4.5 | 3.7 |
| TiO2nucleating agent | 2 – 2.6 | 2.3 |
| ZrO2nucleating agent | 1.5 – 2.2 | 1.9 |
| ZnO | 1 – 1.8 | 1.4 |
| MgO | 0.5 – 1.5 | 1 |
| Na2O | 0.2 – 0.8 | 0.5 |
| K2O | 0 – 0.8 | 0.5 |
| As2O3fining agent in classic composition; arsenic-free melts also offered | 0 – 0.6 | 0.4 |
What surface finishes work on ZERODUR?
Polishes to sub-nanometre rms and accepts ion-beam figuring plus Al/Ag/dielectric and multilayer coatings; a light etch after grinding recovers much of the bending strength.
Equivalent designations
Standards and trade names that resolve to ZERODUR in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Trade names
- Schott ZERODURAstronomical Mirror Glass
- Also called
- Lithium Aluminosilicate Glass-Ceramic
How much does ZERODUR cost?
ZERODUR is a standard-cost glass ($$), cheaper than about 60% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
ZERODUR — frequently asked
What is ZERODUR used for?
ZERODUR is typically used for telescope mirror blanks, astronomical optics, lightweighted honeycomb mirror substrates, metrology reference plates and straightedges, ring laser gyroscope bodies and lithography stages and mask blanks. In short: zero-expansion glass-ceramic.
What is the tensile strength of ZERODUR?
ZERODUR has a typical tensile strength of 30 MPa (4.35 ksi) — weaker than 80% of glass grades. Strength varies by condition: see the 6 listed tempers.
Is ZERODUR easy to machine?
Not especially — machinability is rated poor (20/100, better than 56% of glass grades). Diamond grinding, core drilling, lapping and ultrasonic machining only — no conventional cutting; keep coolant flooded and avoid edge chipping, then acid-etch or fine-grind to remove subsurface damage.
Can ZERODUR be welded?
Not weldable; parts are joined by optical contacting, low-stress epoxy/silicate bonding, frit bonding or Invar/steel flexure mounts.
What surface finishes work on ZERODUR?
Polishes to sub-nanometre rms and accepts ion-beam figuring plus Al/Ag/dielectric and multilayer coatings; a light etch after grinding recovers much of the bending strength.
Can ZERODUR be formed, bent or molded?
Supplied as cast, ceramized blanks; near-net shapes (lightweighted honeycomb mirrors) are produced by machining the blank, not by hot forming, since re-heating above ~600 °C alters the crystal phase and CTE.
What is the maximum service temperature of ZERODUR?
ZERODUR is rated for continuous use to about 500°C (932 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does ZERODUR cost?
ZERODUR is a standard-cost glass ($$), cheaper than about 60% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ZERODUR — Zero Expansion Glass Ceramic, technical data — SCHOTT AG (2023)
- Strength of ZERODUR (TIE-33 / strength brochure) — SCHOTT AG (2021)
- ASM Engineered Materials Handbook Vol. 4: Ceramics and Glasses — ASM International (1991)
- Glass-ceramic property compilations (LAS system) — MatWeb / Ceramic Industry data (2022)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.