MgF2 HP (Hot-pressed polycrystalline)
Other
also Irtran-1
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.
Values for the HP 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 |
|---|---|---|---|---|---|---|
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 |
HPThis page 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 HP?
MgF2 HP is MgF2 in the HP condition — 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. The elastic modulus is 114 GPa (16.5 Msi). MgF2 HP has a density of 3.18 g/cm³ (0.115 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; HP is available on request or by drawing note.
Advantages
- Tough — resists crack growth — 1 MPa·√m (0.91 ksi·√in), better than 87% of glass grades
- Stiff — 114 GPa (16.5 Msi), better than 85% of glass grades
- Conducts heat well — 14.6 W/m·K (8.44 BTU/hr·ft·°F), better than 85% of glass grades
Limitations
- Hard to polish — 65/100, worse than 78% of glass grades
MgF2 HP properties
Typical room-temperature values for MgF2 HP; 14 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 HP has a density of 3.18 g/cm³ (0.115 lb/in³), heavier than 58% of glass grades. It melts at 1,255°C (2,291 °F).
Mechanical10
The elastic modulus is 114 GPa (16.5 Msi).
Thermal5
MgF2 HP is rated for continuous service to 600°C (1,112 °F). It conducts heat at 14.6 W/m·K (8.44 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 HP has an electrical resistivity of 1×10¹² Ω·m.
Chemical & Environmental2
Corrosion resistance is very good (70/100), worse than 58% of glass grades.
Manufacturability2
MgF2 HP's machinability is poor (30/100, better than 71% of glass grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with MgF2 HP
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 HP — frequently asked
What is MgF2 HP used for?
MgF2 HP 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 HP easy to machine?
Not especially — machinability is rated poor (30/100, better than 71% 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 HP be welded?
Not weldable; seal into metal seats with low-stress compliant clamping, epoxy, or low-temperature solder.
What surface finishes work on MgF2 HP?
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 HP 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 HP?
MgF2 HP is rated for continuous use to about 600°C (1,112 °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.