MgF2 EVAP
Grade
also Irtran-1
EVAP = coating/evaporation grade
Use the 99.9–99.99 % granules or crystal pieces as feedstock for e-beam or resistive evaporation of low-index AR coatings; only purity, water/oxygen content and film stress matter, not bulk mechanicals.
Values for the EVAP condition
Other MgF2 tempers and conditions
MgF2 is listed in 3 conditions; see the grade overview at MgF2.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
EVAPThis page Coating/evaporation grade | Use the 99.9–99.99 % granules or crystal pieces as feedstock for e-beam or resistive evaporation of low-index AR coatings; only purity, water/oxygen content and film stress matter, not bulk mechanicals. | — | 40 | 0 | 400 HV | 16 W/m·K |
Hot-pressed polycrystalline | Pick the hot-pressed polycrystal for large-aperture, high-strength IR windows and domes; scatter and absorption above 3–5 µm exceed single crystal and the UV range is unusable. | — | — | — | 560 HV | 15 W/m·K |
SC-UVDefault VUV/UV-grade single crystal | Choose the Bridgman/Stockbarger-grown crystal for deep-UV windows, excimer-laser optics, polarising prisms and space VUV instruments; cut oriented to the optic axis to control birefringence. | — | — | — | — | 21 W/m·K |
What is MgF2 EVAP?
MgF2 EVAP is MgF2 in the EVAP grade — use the 99.9–99.99 % granules or crystal pieces as feedstock for e-beam or resistive evaporation of low-index AR coatings; only purity, water/oxygen content and film stress matter, not bulk mechanicals. The elastic modulus is 115 GPa (16.7 Msi). MgF2 EVAP has a density of 3.15 g/cm³ (0.114 lb/in³), heavier than 58% of glass grades. It melts at 1,255°C (2,291 °F). SC-UV is the default condition FabDigit quotes; EVAP is available on request or by drawing note.
Advantages
- Stiff — 115 GPa (16.7 Msi), better than 85% of glass grades
- Conducts heat well — 16 W/m·K (9.24 BTU/hr·ft·°F), better than 85% of glass grades
Limitations
- Hard to polish — 60/100, worse than 81% of glass grades
MgF2 EVAP properties
Typical room-temperature values for MgF2 EVAP; 16 are specific to this condition. Other listed values are MgF2 reference data and may not represent this condition. Bars are the position among glass grades.
Physical5
MgF2 EVAP has a density of 3.15 g/cm³ (0.114 lb/in³), heavier than 58% of glass grades. It melts at 1,255°C (2,291 °F).
Mechanical10
The elastic modulus is 115 GPa (16.7 Msi).
Thermal5
MgF2 EVAP is rated for continuous service to 400°C (752 °F). It conducts heat at 16 W/m·K (9.24 BTU/hr·ft·°F), better than 85% of glass grades. Thermal expansion is 11.3 µm/m·K (6.28 µin/in·°F).
Electrical3
MgF2 EVAP has an electrical resistivity of 1×10¹¹ Ω·m.
Chemical & Environmental2
Corrosion resistance is good (60/100), worse than 68% of glass grades.
Manufacturability2
MgF2 EVAP's machinability is poor (20/100, better than 56% of glass grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with MgF2 EVAP
Is MgF2 easy to machine?
Grind, saw and cut with diamond tooling only, using light feeds; watch the (110) cleavage plane and keep the birefringent axis orientation under control. Avoid long immersion in water-based coolant.
Can MgF2 be welded?
Not weldable; seal into metal seats with low-stress compliant clamping, epoxy, or low-temperature solder.
Can MgF2 be formed, bent or molded?
Single crystals are grown by the Bridgman crucible-lowering method under a fluorinating atmosphere; polycrystalline parts are vacuum hot-pressed at 900–1000 °C. No cold plastic working is possible.
What surface finishes work on MgF2?
Conventional lapping and polishing reach sub-nanometre RMS roughness. Finished optics are normally coated with MgF2 or multilayer dielectric AR stacks; clean with anhydrous solvents and avoid strong acids and hot, humid conditions.
MgF2 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 |
|---|---|---|
| Mgstoichiometric MgF2 | 38.5 – 39.5 | 39 |
| Ooxygen/oxide impurity, key for VUV transmission | ≤ 0.05 | 0.01 |
| Fetransition-metal impurity limit for UV grade | ≤ 0 | 3×10⁻⁴ |
| F | ≥ 60.5 (balance) | — |
MgF2 EVAP — frequently asked
What is MgF2 EVAP used for?
MgF2 EVAP is typically used for AR coatings, UV windows, waveplates and excimer laser optics. In short: standard low-index AR material; deep-UV to mid-IR transmission; birefringent, needs axis control.
Is MgF2 EVAP easy to machine?
Not especially — machinability is rated poor (20/100, better than 56% of glass grades). Grind, saw and cut with diamond tooling only, using light feeds; watch the (110) cleavage plane and keep the birefringent axis orientation under control. Avoid long immersion in water-based coolant.
Can MgF2 EVAP be welded?
Not weldable; seal into metal seats with low-stress compliant clamping, epoxy, or low-temperature solder.
What surface finishes work on MgF2 EVAP?
Conventional lapping and polishing reach sub-nanometre RMS roughness. Finished optics are normally coated with MgF2 or multilayer dielectric AR stacks; clean with anhydrous solvents and avoid strong acids and hot, humid conditions.
Can MgF2 EVAP be formed, bent or molded?
Single crystals are grown by the Bridgman crucible-lowering method under a fluorinating atmosphere; polycrystalline parts are vacuum hot-pressed at 900–1000 °C. No cold plastic working is possible.
What is the maximum service temperature of MgF2 EVAP?
MgF2 EVAP is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- Magnesium Fluoride (MgF2) Optical Material Data — Crystran Ltd (2023)
- MgF2 Single Crystal Datasheet — Korth Kristalle GmbH (2022)
- Handbook of Optical Constants of Solids (MgF2, Dodge dispersion) — Academic Press (1985)
- CRC Handbook of Chemistry and Physics — CRC Press (2020)
- Infrared window materials: Irtran-1 hot-pressed MgF2 properties — ASM/optical materials compilations (2010)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.